From 2828de4d3f04e9382559b83e3002894da3dbf937 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <m.kroening@hotmail.de>
Date: Sun, 8 Sep 2019 13:05:52 +0200
Subject: [PATCH 01/65] Don't enforce line endings

Line endings are currently very inconsistent.
To be able to make concise commits easily without having every line's ending changed automatically, we should not enforce the line ending.
Another reason to unset the line endings setting is to be able to make use of git's autocrlf. See [editorconfig/editorconfig#226](https://github.com/editorconfig/editorconfig/issues/226#issuecomment-339153692)
---
 .editorconfig | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/.editorconfig b/.editorconfig
index 815d8b54c0..33a6320099 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -4,7 +4,6 @@ root = true
 [*]
 indent_style = tab
 indent_size = 4
-end_of_line = lf
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
@@ -18,6 +17,3 @@ indent_style = space
 
 [*.md]
 trim_trailing_whitespace = false
-
-[configure.ac]
-end_of_line = lf

From 1099c8297ab878b6f3250bc136c4bc7a83711d5f Mon Sep 17 00:00:00 2001
From: Elias Kunnas <elias@kunnas.com>
Date: Wed, 23 Oct 2019 20:50:50 +0300
Subject: [PATCH 02/65] Fix LRC parsing crash for unrecognized values

---
 src/LyricsLoader.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/LyricsLoader.cpp b/src/LyricsLoader.cpp
index ca2bb8da43..ea820716d5 100644
--- a/src/LyricsLoader.cpp
+++ b/src/LyricsLoader.cpp
@@ -90,10 +90,11 @@ bool LyricsLoader::LoadFromLRCFile(const RString& sPath, Song& out)
 		// offsets each timestamp after the offset by that amount.
 		//float fLyricOffset = 0.0f;
 
+		// Enforce strict timestamp format to prevent crashing the program.
+		vector<RString> dummy;
+		static Regex timestamp("^([0-9]+:){0,2}[0-9]+(.[0-9]*)?$");
+		if (timestamp.Compare(sValueName, dummy))
 		{
-			/* If we've gotten this far, and no other statement caught this
-			 * value before this does, assume it's a time value. */
-
 			LyricSegment seg;
 			seg.m_Color = CurrentColor;
 			seg.m_fStartTime = HHMMSSToSeconds(sValueName);

From cb10b61d34a4d29437f1569a99e35bd4b7c52c4b Mon Sep 17 00:00:00 2001
From: Matias Hilden <domewolf@gmail.com>
Date: Sun, 8 Dec 2019 13:48:25 +0200
Subject: [PATCH 03/65] fix leftover macro loop in JACK sound driver

---
 src/arch/Sound/RageSoundDriver_JACK.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/arch/Sound/RageSoundDriver_JACK.cpp b/src/arch/Sound/RageSoundDriver_JACK.cpp
index f0b291173e..5a68402fbe 100644
--- a/src/arch/Sound/RageSoundDriver_JACK.cpp
+++ b/src/arch/Sound/RageSoundDriver_JACK.cpp
@@ -4,7 +4,6 @@
 #include "RageUtil.h"
 #include "PrefsManager.h"
 #include "ProductInfo.h"
-#include "Foreach.h"
 
 REGISTER_SOUND_DRIVER_CLASS( JACK );
 
@@ -144,9 +143,9 @@ RString RageSoundDriver_JACK::ConnectPorts()
 		// jack_port_name to use their canonical name.  (I'm not sure 
 		// if that second step is necessary, I've seen something about 
 		// "aliases" in the docs.)
-		FOREACH( RString, portNames, portName )
+		for ( RString const &portName : portNames )
 		{
-			jack_port_t *out = jack_port_by_name( client, *portName );
+			jack_port_t *out = jack_port_by_name( client, portName );
 			// Make sure the port is a sink.
 			if( ! ( jack_port_flags( out ) & JackPortIsInput ) )
 				continue;

From 123b01930e104851aec3daa491066fceff98ab48 Mon Sep 17 00:00:00 2001
From: Prcuvu <prcuvu@gmail.com>
Date: Sun, 22 Dec 2019 18:38:07 +0800
Subject: [PATCH 04/65] Force Lua to be compiled as C++ code when using MSVC

The setjmp/longjmp error handling mechanism may fail with Microsoft C++ since
they utilize the same stack-unwinding mechanism with C++ exception handling.
Lua calling longjmp after luaD_rawrunprotected returns causes unpredictable
behaviour. On Windows x64 build, this causes lua_error to crash the whole
StepMania program.

Lua provides the same macros to utilize C++ throw/catch, which effectively
solve the problem. Just specify Lua library as C++ code to enable them.

Reference: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/longjmp
---
 extern/CMakeProject-lua.cmake | 1 +
 src/EnumHelper.h              | 4 ++++
 src/LuaManager.h              | 4 ++++
 3 files changed, 9 insertions(+)

diff --git a/extern/CMakeProject-lua.cmake b/extern/CMakeProject-lua.cmake
index b2106d4878..70d45a95c7 100644
--- a/extern/CMakeProject-lua.cmake
+++ b/extern/CMakeProject-lua.cmake
@@ -64,6 +64,7 @@ set_property(TARGET "lua-5.1" PROPERTY FOLDER "External Libraries")
 
 if(MSVC)
   sm_add_compile_definition("lua-5.1" _CRT_SECURE_NO_WARNINGS)
+  sm_add_compile_flag("lua-5.1" /TP)
 endif(MSVC)
 
 disable_project_warnings("lua-5.1")
diff --git a/src/EnumHelper.h b/src/EnumHelper.h
index 230e21624b..d620830ecc 100644
--- a/src/EnumHelper.h
+++ b/src/EnumHelper.h
@@ -5,10 +5,14 @@
 #include "RageUtil.h"
 #include <memory>
 
+#ifndef _MSC_VER
 extern "C"
 {
+#endif
 #include "../extern/lua-5.1/src/lua.h"
+#ifndef _MSC_VER
 }
+#endif
 
 /** @brief A general foreach loop for enumerators, going up to a max value. */
 #define FOREACH_ENUM_N( e, max, var )	for( e var=(e)0; var<max; enum_add<e>( var, +1 ) )
diff --git a/src/LuaManager.h b/src/LuaManager.h
index b69d24e865..e0df497a9b 100644
--- a/src/LuaManager.h
+++ b/src/LuaManager.h
@@ -8,12 +8,16 @@ class RageMutex;
 class XNode;
 class LuaReference;
 
+#ifndef _MSC_VER
 extern "C"
 {
+#endif
 #include "../extern/lua-5.1/src/lua.h"
 #include "../extern/lua-5.1/src/lualib.h"
 #include "../extern/lua-5.1/src/lauxlib.h"
+#ifndef _MSC_VER
 }
+#endif
 
 // For Dialog::Result
 #include "arch/Dialog/Dialog.h"

From 532c430d8f9e7484da207f63b180187388bcc9a4 Mon Sep 17 00:00:00 2001
From: Prcuvu <prcuvu@gmail.com>
Date: Tue, 31 Dec 2019 16:04:17 +0800
Subject: [PATCH 05/65] Fix XInput library linkage for compatibility down to
 Windows Vista

---
 src/arch/InputHandler/InputHandler_DirectInput.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/arch/InputHandler/InputHandler_DirectInput.cpp b/src/arch/InputHandler/InputHandler_DirectInput.cpp
index d04196bf05..deb9a9a8be 100644
--- a/src/arch/InputHandler/InputHandler_DirectInput.cpp
+++ b/src/arch/InputHandler/InputHandler_DirectInput.cpp
@@ -14,7 +14,11 @@
 
 #include "InputHandler_DirectInputHelper.h"
 
+#ifdef NTDDI_WIN8 // Link to Xinput9_1_0.lib on Windows 8 SDK and above to ensure linkage to Xinput9_1_0.dll
+#pragma comment(lib, "Xinput9_1_0.lib")
+#else
 #pragma comment(lib, "xinput.lib")
+#endif
 
 #include <XInput.h>
 #include <WbemIdl.h>

From a124b129d112d59898dd136a8ceb390e5d0afd61 Mon Sep 17 00:00:00 2001
From: Prcuvu <prcuvu@gmail.com>
Date: Tue, 31 Dec 2019 23:19:03 +0800
Subject: [PATCH 06/65] Update URLs in README.md

---
 README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 86ffc7ebb1..a6a00f4149 100644
--- a/README.md
+++ b/README.md
@@ -23,9 +23,9 @@ StepMania can be compiled using [CMake](http://www.cmake.org/). More information
 
 ## Resources
 
-* Website: http://www.stepmania.com/
+* Website: https://www.stepmania.com/
 * IRC: irc.freenode.net/#stepmania-devs
-* Lua for SM5: https://dguzek.github.io/Lua-For-SM5/
+* Lua for SM5: https://quietly-turning.github.io/Lua-For-SM5/
 * Lua API Documentation can be found in the Docs folder.
 
 ## Licensing Terms

From de4dc62846ab958834a5d6bc2f63fd2eb36d522b Mon Sep 17 00:00:00 2001
From: Prcuvu <prcuvu@gmail.com>
Date: Sat, 8 Feb 2020 15:46:00 +0800
Subject: [PATCH 07/65] Split Chinese language into Simplified script and
 Traditional script

ArchHooks function modified for Windows.
---
 Themes/_fallback/Languages/de.ini                  |  3 ++-
 Themes/_fallback/Languages/en.ini                  |  3 ++-
 Themes/_fallback/Languages/es.ini                  |  3 ++-
 Themes/_fallback/Languages/fr.ini                  |  3 ++-
 Themes/_fallback/Languages/ja.ini                  |  3 ++-
 Themes/_fallback/Languages/nl.ini                  |  3 ++-
 Themes/_fallback/Languages/pl.ini                  |  3 ++-
 Themes/_fallback/Languages/{zh.ini => zh-Hant.ini} |  3 ++-
 Themes/legacy/Languages/{zh.ini => zh-Hant.ini}    |  0
 src/RageUtil.cpp                                   |  4 ++--
 src/arch/ArchHooks/ArchHooks_Win32Static.cpp       | 14 +++++++++++++-
 11 files changed, 31 insertions(+), 11 deletions(-)
 rename Themes/_fallback/Languages/{zh.ini => zh-Hant.ini} (99%)
 rename Themes/legacy/Languages/{zh.ini => zh-Hant.ini} (100%)

diff --git a/Themes/_fallback/Languages/de.ini b/Themes/_fallback/Languages/de.ini
index ce7a5c844a..49e39ae524 100644
--- a/Themes/_fallback/Languages/de.ini
+++ b/Themes/_fallback/Languages/de.ini
@@ -2594,7 +2594,8 @@ Wolof=Wolof
 Xhosa=isiXhosa
 Yiddish=Yiddish
 Yoruba=Yorùbá
-Chinese=中文
+Chinese (Simplified)=简体中文
+Chinese (Traditional)=繁體中文
 Zulu=isiZulu
 
 [ScreenPlayerOptions]
diff --git a/Themes/_fallback/Languages/en.ini b/Themes/_fallback/Languages/en.ini
index d9fec0ab49..28e05ce007 100644
--- a/Themes/_fallback/Languages/en.ini
+++ b/Themes/_fallback/Languages/en.ini
@@ -2645,7 +2645,8 @@ Wolof=Wolof
 Xhosa=isiXhosa
 Yiddish=Yiddish
 Yoruba=Yorùbá
-Chinese=中文
+Chinese (Simplified)=简体中文
+Chinese (Traditional)=繁體中文
 Zulu=isiZulu
 
 [ScreenPlayerOptions]
diff --git a/Themes/_fallback/Languages/es.ini b/Themes/_fallback/Languages/es.ini
index d48a6102c9..21d79f6e72 100644
--- a/Themes/_fallback/Languages/es.ini
+++ b/Themes/_fallback/Languages/es.ini
@@ -2564,7 +2564,8 @@ Wolof=Wolof
 Xhosa=isiXhosa
 Yiddish=Yiddish
 Yoruba=Yorùbá
-Chinese=中文
+Chinese (Simplified)=简体中文
+Chinese (Traditional)=繁體中文
 Zulu=isiZulu
 
 [ScreenPlayerOptions]
diff --git a/Themes/_fallback/Languages/fr.ini b/Themes/_fallback/Languages/fr.ini
index 36d2830bf4..8f293d688d 100644
--- a/Themes/_fallback/Languages/fr.ini
+++ b/Themes/_fallback/Languages/fr.ini
@@ -2576,7 +2576,8 @@ Wolof=Wolof
 Xhosa=isiXhosa
 Yiddish=Yiddish
 Yoruba=Yorùbá
-Chinese=中文
+Chinese (Simplified)=简体中文
+Chinese (Traditional)=繁體中文
 Zulu=isiZulu
 
 [ScreenPlayerOptions]
diff --git a/Themes/_fallback/Languages/ja.ini b/Themes/_fallback/Languages/ja.ini
index 8bbd65d2bf..88dfad34be 100644
--- a/Themes/_fallback/Languages/ja.ini
+++ b/Themes/_fallback/Languages/ja.ini
@@ -2785,7 +2785,8 @@ Wolof=Wolof
 Xhosa=isiXhosa
 Yiddish=Yiddish
 Yoruba=Yorùbá
-Chinese=中文
+Chinese (Simplified)=简体中文
+Chinese (Traditional)=繁體中文
 Zulu=isiZulu
 
 
diff --git a/Themes/_fallback/Languages/nl.ini b/Themes/_fallback/Languages/nl.ini
index 7165044ed0..25f3c078a2 100644
--- a/Themes/_fallback/Languages/nl.ini
+++ b/Themes/_fallback/Languages/nl.ini
@@ -2576,7 +2576,8 @@ Wolof=Wolof
 Xhosa=isiXhosa
 Yiddish=Yiddish
 Yoruba=Yorùbá
-Chinese=中文
+Chinese (Simplified)=简体中文
+Chinese (Traditional)=繁體中文
 Zulu=isiZulu
 
 [ScreenPlayerOptions]
diff --git a/Themes/_fallback/Languages/pl.ini b/Themes/_fallback/Languages/pl.ini
index 0a920f6b57..0903860618 100644
--- a/Themes/_fallback/Languages/pl.ini
+++ b/Themes/_fallback/Languages/pl.ini
@@ -2551,7 +2551,8 @@ Wolof=Wolof
 Xhosa=isiXhosa
 Yiddish=Yiddish
 Yoruba=Yorùbá
-Chinese=中文
+Chinese (Simplified)=简体中文
+Chinese (Traditional)=繁體中文
 Zulu=isiZulu
 
 [ScreenPlayerOptions]
diff --git a/Themes/_fallback/Languages/zh.ini b/Themes/_fallback/Languages/zh-Hant.ini
similarity index 99%
rename from Themes/_fallback/Languages/zh.ini
rename to Themes/_fallback/Languages/zh-Hant.ini
index 92ac6f2d91..3e2b83195d 100644
--- a/Themes/_fallback/Languages/zh.ini
+++ b/Themes/_fallback/Languages/zh-Hant.ini
@@ -2622,7 +2622,8 @@ Wolof=Wolof
 Xhosa=isiXhosa
 Yiddish=Yiddish
 Yoruba=Yorùbá
-Chinese=中文
+Chinese (Simplified)=简体中文
+Chinese (Traditional)=繁體中文
 Zulu=isiZulu
 
 [ScreenPlayerOptions]
diff --git a/Themes/legacy/Languages/zh.ini b/Themes/legacy/Languages/zh-Hant.ini
similarity index 100%
rename from Themes/legacy/Languages/zh.ini
rename to Themes/legacy/Languages/zh-Hant.ini
diff --git a/src/RageUtil.cpp b/src/RageUtil.cpp
index a882ba962c..24f41b32f0 100644
--- a/src/RageUtil.cpp
+++ b/src/RageUtil.cpp
@@ -547,7 +547,6 @@ RString ConvertI64FormatString( const RString &sStr ) { return sStr; }
 #endif
 
 /* ISO-639-1 codes: http://www.loc.gov/standards/iso639-2/php/code_list.php
- * native forms: http://people.w3.org/rishida/names/languages.html
  * We don't use 3-letter codes, so we don't bother supporting them. */
 static const LanguageInfo g_langs[] =
 {
@@ -688,7 +687,8 @@ static const LanguageInfo g_langs[] =
 	{"xh", "Xhosa"},
 	{"yi", "Yiddish"},
 	{"yo", "Yoruba"},
-	{"zh", "Chinese"},
+	{"zh-Hans", "Chinese (Simplified)"},
+	{"zh-Hant", "Chinese (Traditional)"},
 	{"zu", "Zulu"},
 };
 
diff --git a/src/arch/ArchHooks/ArchHooks_Win32Static.cpp b/src/arch/ArchHooks/ArchHooks_Win32Static.cpp
index 9e6ce39a6a..369e93d6a6 100644
--- a/src/arch/ArchHooks/ArchHooks_Win32Static.cpp
+++ b/src/arch/ArchHooks/ArchHooks_Win32Static.cpp
@@ -98,7 +98,19 @@ static RString LangIdToString( LANGID l )
 	case LANG_ARABIC: return "ar";
 	case LANG_BULGARIAN: return "bg";
 	case LANG_CATALAN: return "ca";
-	case LANG_CHINESE: return "zh";
+	case LANG_CHINESE:
+	{
+		switch (SUBLANGID(l))
+		{
+		case SUBLANG_CHINESE_TRADITIONAL:
+		case SUBLANG_CHINESE_HONGKONG:
+		case SUBLANG_CHINESE_MACAU:
+			return "zh-Hant";
+		case SUBLANG_CHINESE_SIMPLIFIED:
+		case SUBLANG_CHINESE_SINGAPORE:
+			return "zh-Hans";
+		}
+	}
 	case LANG_CZECH: return "cs";
 	case LANG_DANISH: return "da";
 	case LANG_GERMAN: return "de";

From d893c84b7bc15229338928f3b092fdcbbd414a70 Mon Sep 17 00:00:00 2001
From: Prcuvu <prcuvu@gmail.com>
Date: Sat, 8 Feb 2020 16:08:02 +0800
Subject: [PATCH 08/65] ArchHooks modified for Unix

---
 src/arch/ArchHooks/ArchHooks_Unix.cpp | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/arch/ArchHooks/ArchHooks_Unix.cpp b/src/arch/ArchHooks/ArchHooks_Unix.cpp
index 8f67a19c2f..ce2e1dfd72 100644
--- a/src/arch/ArchHooks/ArchHooks_Unix.cpp
+++ b/src/arch/ArchHooks/ArchHooks_Unix.cpp
@@ -179,13 +179,29 @@ RString ArchHooks::GetPreferredLanguage()
 {
 	RString locale;
 
-	if(getenv("LANG"))
+	if (getenv("LANG"))
 	{
 		locale = getenv("LANG");
-		locale = locale.substr(0,2);
+		RString region = locale.substr(3, 2);
+		locale = locale.substr(0, 2);
+
+		if (locale == "zh")
+		{
+			if (region == "CN" || region == "SG")
+			{
+				locale = "zh-Hans";
+			}
+			else if (region == "HK" || region == "TW")
+			{
+				locale = "zh-Hant";
+			}
+		}
 	}
 	else
+	{
+		LOG->Warn("Unable to determine system language. Using English.");
 		locale = "en";
+	}
 
 	return locale;
 }

From 2baade1dd7a90caacad96a2874dfdb06833ac27c Mon Sep 17 00:00:00 2001
From: Prcuvu <prcuvu@gmail.com>
Date: Sat, 8 Feb 2020 17:03:27 +0800
Subject: [PATCH 09/65] ArchHooks modified for macOS

---
 src/arch/ArchHooks/ArchHooks_MacOSX.mm | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/arch/ArchHooks/ArchHooks_MacOSX.mm b/src/arch/ArchHooks/ArchHooks_MacOSX.mm
index def9a1b7a5..627c1ba84e 100644
--- a/src/arch/ArchHooks/ArchHooks_MacOSX.mm
+++ b/src/arch/ArchHooks/ArchHooks_MacOSX.mm
@@ -261,7 +261,14 @@ RString ArchHooks::GetPreferredLanguage()
 		// MacRoman agrees with ASCII in the low-order 7 bits.
 		const char *str = CFStringGetCStringPtr( lang, kCFStringEncodingMacRoman );
 		if( str )
+		{
 			ret = RString( str, 2 );
+			if (ret == "zh")
+			{
+				ret = RString(str, 7);
+				ret[2] = '-';
+			}
+		}
 		else
 			LOG->Warn( "Unable to determine system language. Using English." );
 	}

From b38377403ebd7cc3dcad9bd884f9ccc97ec74a29 Mon Sep 17 00:00:00 2001
From: Prcuvu <prcuvu@gmail.com>
Date: Sat, 8 Feb 2020 17:08:25 +0800
Subject: [PATCH 10/65] Add LOG->Warn on fallback to English, for consistency
 on all platforms

---
 src/arch/ArchHooks/ArchHooks_Win32Static.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/arch/ArchHooks/ArchHooks_Win32Static.cpp b/src/arch/ArchHooks/ArchHooks_Win32Static.cpp
index 369e93d6a6..6325bc5df0 100644
--- a/src/arch/ArchHooks/ArchHooks_Win32Static.cpp
+++ b/src/arch/ArchHooks/ArchHooks_Win32Static.cpp
@@ -1,6 +1,7 @@
 #include "global.h"
 #include "ArchHooks.h"
 #include "RageUtil.h"
+#include "RageLog.h"
 #include "archutils/Win32/SpecialDirs.h"
 #include "ProductInfo.h"
 #include "RageFileManager.h"
@@ -166,7 +167,7 @@ static RString LangIdToString( LANGID l )
 	// These aren't present in the VC6 headers. We'll never have translations to these languages anyway. -C
 	//case LANG_MONGOLIAN: return "mn";
 	//case LANG_GALICIAN: return "gl";
-	default:
+	default: LOG->Warn("Unable to determine system language. Using English.");
 	case LANG_ENGLISH: return "en";
 	}
 }

From 360db59e0db7a7324dbd641ec6f7e9510a644a36 Mon Sep 17 00:00:00 2001
From: Prcuvu <prcuvu@gmail.com>
Date: Tue, 11 Feb 2020 01:46:29 +0800
Subject: [PATCH 11/65] Fix Texture Font Generator for Windows x64 build

---
 src/CMakeProject-texture.cmake             |  5 ++++-
 src/Texture Font Generator/TextureFont.cpp |  2 +-
 src/Texture Font Generator/Utils.h         | 21 +++++++++++++++++++--
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/CMakeProject-texture.cmake b/src/CMakeProject-texture.cmake
index 1e4c0fa38e..70ccd5ab16 100644
--- a/src/CMakeProject-texture.cmake
+++ b/src/CMakeProject-texture.cmake
@@ -41,6 +41,8 @@ if(NOT WITH_STATIC_LINKING)
   sm_add_compile_definition("TextureFontGenerator" _AFXDLL)
 endif()
 
+sm_add_compile_definition("TextureFontGenerator" CMAKE_POWERED)
+
 list(APPEND TEXTURE_LINK_LIB "zlib" "png")
 
 target_link_libraries("TextureFontGenerator" ${TEXTURE_LINK_LIB})
@@ -49,7 +51,8 @@ list(APPEND TEXTURE_INCLUDE_DIRS
             "${TEXTURE_DIR}"
             "${TEXTURE_DIR}/res"
             "${SM_EXTERN_DIR}/zlib"
-            "${SM_EXTERN_DIR}/libpng/include")
+            "${SM_EXTERN_DIR}/libpng/include"
+            "${SM_SRC_DIR}/generated")
 
 target_include_directories("TextureFontGenerator"
                            PUBLIC ${TEXTURE_INCLUDE_DIRS})
diff --git a/src/Texture Font Generator/TextureFont.cpp b/src/Texture Font Generator/TextureFont.cpp
index 170f8ce420..8b00a3c403 100644
--- a/src/Texture Font Generator/TextureFont.cpp	
+++ b/src/Texture Font Generator/TextureFont.cpp	
@@ -335,7 +335,7 @@ void TextureFont::FormatFontPage( int iPage, HDC hDC )
 		}
 
 		++iCol;
-		if( iCol == pPage->m_iNumFramesY )
+		if( iCol == pPage->m_iNumFramesX )
 		{
 			iCol = 0;
 			++iRow;
diff --git a/src/Texture Font Generator/Utils.h b/src/Texture Font Generator/Utils.h
index 6bae2913e5..0ca0bddfbf 100644
--- a/src/Texture Font Generator/Utils.h	
+++ b/src/Texture Font Generator/Utils.h	
@@ -1,9 +1,22 @@
 #ifndef UTILS_H
 #define UTILS_H
 
-inline float truncf( float f )	{ return float(int(f)); };
-inline float roundf( float f )	{ if(f < 0) return truncf(f-0.5f); return truncf(f+0.5f); };
+#if defined(CMAKE_POWERED)
+#include "config.hpp"
+#elif defined(HAVE_CONFIG_H)
+#include "config.h"
+#endif
 
+#if !defined(HAVE_TRUNCF)
+inline float truncf( float f )	{ return float(int(f)); };
+#endif
+
+#if !defined(HAVE_ROUNDF)
+inline float roundf( float f )	{ if(f < 0) return truncf(f-0.5f); return truncf(f+0.5f); };
+#endif
+
+#if !defined(HAVE_LRINTF)
+#if defined(_MSC_VER) && defined(_X86_)
 inline long int lrintf( float f )
 {
 	int retval;
@@ -13,6 +26,10 @@ inline long int lrintf( float f )
 
 	return retval;
 }
+#else
+#define lrintf(x) ((int)rint(x))
+#endif
+#endif
 
 struct Surface
 {

From 50de3a1f2ddfe11d7f466638fb0d5be7ca90a9b0 Mon Sep 17 00:00:00 2001
From: x0rbl <46559321+x0rbl@users.noreply.github.com>
Date: Tue, 11 Feb 2020 12:15:16 -0800
Subject: [PATCH 12/65] Fix two disqualification bugs: C-mods and rate mods now
 properly disqualify (#1965)

---
 src/GameState.cpp | 6 ++++++
 src/Steps.cpp     | 4 +++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/GameState.cpp b/src/GameState.cpp
index febaf7b235..be32f36790 100644
--- a/src/GameState.cpp
+++ b/src/GameState.cpp
@@ -1915,6 +1915,12 @@ bool GameState::CurrentOptionsDisqualifyPlayer( PlayerNumber pn )
 		return false;
 
 	const PlayerOptions &po = m_pPlayerState[pn]->m_PlayerOptions.GetPreferred();
+	const SongOptions &so = m_SongOptions.GetPreferred();
+
+	// Playing a song/course at a slower music rate should disqualify score. -x0rbl
+	if (so.m_fMusicRate < 1.0) {
+		return true;
+	}
 
 	// Check the stored player options for disqualify.  Don't disqualify because
 	// of mods that were forced.
diff --git a/src/Steps.cpp b/src/Steps.cpp
index 8b6643dfc9..38129a57c7 100644
--- a/src/Steps.cpp
+++ b/src/Steps.cpp
@@ -595,7 +595,9 @@ bool Steps::HasSignificantTimingChanges() const
 	if( timing->HasBpmChanges() )
 	{
 		// check to see if these changes are significant.
-		if( (GetMaxBPM() - GetMinBPM()) > 3.000f )
+		DisplayBpms bpms;
+		m_pSong->GetDisplayBpms(bpms);
+		if (bpms.GetMax() - bpms.GetMin() > 3.000f)
 			return true;
 	}
 

From 0b34a0df3adc33a5e66147a04a2d7e9d5721a98c Mon Sep 17 00:00:00 2001
From: x0rbl <46559321+x0rbl@users.noreply.github.com>
Date: Wed, 12 Feb 2020 06:10:28 -0800
Subject: [PATCH 13/65] Fix crash with AllowMultipleHighScoreWithSameName
 (#1963)

---
 src/HighScore.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/HighScore.cpp b/src/HighScore.cpp
index 38ce9420b2..626df6c22f 100644
--- a/src/HighScore.cpp
+++ b/src/HighScore.cpp
@@ -405,7 +405,7 @@ void HighScoreList::LoadFromNode( const XNode* pHighScoreList )
 
 void HighScoreList::RemoveAllButOneOfEachName()
 {
-	for (vector<HighScore>::iterator i = vHighScores.begin(); i != vHighScores.end() - 1; ++i)
+	for (vector<HighScore>::iterator i = vHighScores.begin(); i != vHighScores.end(); ++i)
 	{
 		for( vector<HighScore>::iterator j = i+1; j != vHighScores.end(); j++ )
 		{

From 1d365fbc1800767128996b415126c343e503f3d3 Mon Sep 17 00:00:00 2001
From: teejusb <5017202+teejusb@users.noreply.github.com>
Date: Wed, 8 Apr 2020 22:01:16 -0700
Subject: [PATCH 14/65] Fix float parsing errors

---
 src/RageUtil.cpp | 37 ++++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/src/RageUtil.cpp b/src/RageUtil.cpp
index 24f41b32f0..ae801f501a 100644
--- a/src/RageUtil.cpp
+++ b/src/RageUtil.cpp
@@ -1877,27 +1877,38 @@ void MakeLower( wchar_t *p, size_t iLen )
 
 float StringToFloat( const RString &sString )
 {
-	RString toTrim = sString;
-	Trim(toTrim);
-	if (toTrim.size() == 0)
+	try
 	{
-		return 0;
+		float fOut = std::stof(sString);
+		if (!isfinite(fOut))
+		{
+			fOut = 0.0f;
+		}
+		return fOut;
 	}
-	return std::stof(toTrim);
+	catch(...)
+	{
+		return 0.0f;
+	}	
 }
 
 bool StringToFloat( const RString &sString, float &fOut )
 {
-	RString toTrim = sString;
-	Trim(toTrim);
-	if (toTrim.size() == 0)
+	try
 	{
-		return false;
+		fOut = std::stof(sString);
+		if (!isfinite(fOut))
+		{
+			fOut = 0.0f;
+			return false;
+		}
+		return true;
 	}
-	char *endPtr;
-
-	fOut = strtof( toTrim, &endPtr );
-	return *endPtr == '\0' && isfinite( fOut );
+	catch(...)
+	{
+		fOut = 0.0f;
+		return false;
+	}	
 }
 
 RString FloatToString( const float &num )

From 620ef3609df6f7fe21b6654bbca426cfdd45ef86 Mon Sep 17 00:00:00 2001
From: teejusb <5017202+teejusb@users.noreply.github.com>
Date: Wed, 8 Apr 2020 22:41:19 -0700
Subject: [PATCH 15/65] Revert to use std::strtof insted of std::stof to make
 travis happy

---
 src/RageUtil.cpp | 34 ++++++++--------------------------
 1 file changed, 8 insertions(+), 26 deletions(-)

diff --git a/src/RageUtil.cpp b/src/RageUtil.cpp
index ae801f501a..445f4a776d 100644
--- a/src/RageUtil.cpp
+++ b/src/RageUtil.cpp
@@ -1877,38 +1877,20 @@ void MakeLower( wchar_t *p, size_t iLen )
 
 float StringToFloat( const RString &sString )
 {
-	try
+	float fOut = std::strtof(sString, nullptr);
+	if (!isfinite(fOut))
 	{
-		float fOut = std::stof(sString);
-		if (!isfinite(fOut))
-		{
-			fOut = 0.0f;
-		}
-		return fOut;
+		fOut = 0.0f;
 	}
-	catch(...)
-	{
-		return 0.0f;
-	}	
+	return fOut;
 }
 
 bool StringToFloat( const RString &sString, float &fOut )
 {
-	try
-	{
-		fOut = std::stof(sString);
-		if (!isfinite(fOut))
-		{
-			fOut = 0.0f;
-			return false;
-		}
-		return true;
-	}
-	catch(...)
-	{
-		fOut = 0.0f;
-		return false;
-	}	
+	char *endPtr = nullptr;
+
+	fOut = std::strtof(sString, &endPtr);
+	return sString.size() && *endPtr == '\0' && isfinite(fOut);
 }
 
 RString FloatToString( const float &num )

From c306c13112851aa60e218aa473fec6890d3a8bf8 Mon Sep 17 00:00:00 2001
From: tertu <flameshadowxeroshin@gmail.com>
Date: Thu, 16 Apr 2020 08:39:32 -0500
Subject: [PATCH 16/65] fix documentation for lua.RunWithThreadVariables

---
 Docs/Luadoc/LuaDocumentation.xml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Docs/Luadoc/LuaDocumentation.xml b/Docs/Luadoc/LuaDocumentation.xml
index d058433376..92c27526a1 100644
--- a/Docs/Luadoc/LuaDocumentation.xml
+++ b/Docs/Luadoc/LuaDocumentation.xml
@@ -823,7 +823,8 @@ save yourself some time, copy this for undocumented things:
 		error is optional an defaults to "Script error occurred.".  error_type is optional and defaults to "LUA_ERROR".
 	</Function>
 	<Function name='RunWithThreadVariables' return='int' arguments='function func, table t, ...'>
-		Calls <code>func(...)</code> with two LuaThreadVariables set, and returns the return values of <code>func()</code>.
+		Calls <code>func(...)</code> with LuaThreadVariables set according to the keys and values of <code>t</code>, and returns the return values of <code>func()</code>.<br/>
+		For example, if <code>t</code> is <code>{x=12}</code>, calling <code>Var "x"</code> from <code>func</code> will return 12.
 	</Function>
 	<Function name='Trace' return='void' arguments='string sString'>
 		Writes <code>sString</code> to log.txt. Aliased by

From 79272eedde9ab0b7259836dfb328a7445863770c Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Fri, 17 Apr 2020 17:30:26 -0400
Subject: [PATCH 17/65] fix+clarify multiple issues in LuaDocumentation

* removed ClearEnterMappedKeys from global functions
* typo fix in rawequal
* fix explanations of global SecondsToXXXX functions
* add to explanation of lua.ReportScriptError
* explain how ActorSound class can be used in Lua as "Sound"
* fix explanation for Course.GetCouseDir
* fix specified args for GAMESTATE.GetPreferredDifficulty
* remove HighScore.GetHighScore since it doesn't exist
* document special args for ScreenSelectProfile.SetProfileIndex
* fix specified args for Style.GetColumnInfo
* add examples of return value for Style.GetColumnInfo
* remove lingering mentions of SM4
---
 Docs/Luadoc/LuaDocumentation.xml | 57 +++++++++++++++++---------------
 1 file changed, 30 insertions(+), 27 deletions(-)

diff --git a/Docs/Luadoc/LuaDocumentation.xml b/Docs/Luadoc/LuaDocumentation.xml
index 92c27526a1..d4583be1dc 100644
--- a/Docs/Luadoc/LuaDocumentation.xml
+++ b/Docs/Luadoc/LuaDocumentation.xml
@@ -67,9 +67,6 @@ save yourself some time, copy this for undocumented things:
 		CLAMP is an all-female Japanese mangaka group that formed in the mid 1980s.
 		Erm, I mean... Clamps <code>fValue</code> between <code>fLow</code> and <code>fHigh</code>.
 	</Function>
-	<Function name='ClearEnterMappedKeys' theme='_fallback' return='void' arguments=''>
-		[04 KeymapGuard.lua]
-	</Function>
 	<Function name='CloseConnection' return='void' arguments=''>
 		Closes any connection to an online server.
 	</Function>
@@ -465,7 +462,7 @@ save yourself some time, copy this for undocumented things:
 	<Function name='ProductVersion' return='string' arguments=''>
 		Returns the product version.
 	</Function>
-	<Function name='rawequal' return='bool' arguments='various v1, varoius v2'>
+	<Function name='rawequal' return='bool' arguments='various v1, various v2'>
 		"Checks whether <code>v1</code> is equal to <code>v2</code>, without invoking any metamethod."
 	</Function>
 	<Function name='rawget' return='various' arguments='table t, various index'>
@@ -530,22 +527,22 @@ save yourself some time, copy this for undocumented things:
 		Returns the current second.
 	</Function>
 	<Function name='SecondsToHHMMSS' return='string' arguments='float fSecs'>
-		Converts <code>fSecs</code> to Minutes:Seconds:Milliseconds format using two digits for each section.
+		Converts <code>fSecs</code> to Hours:Minutes:Seconds format using two digits for each section.
 	</Function>
 	<Function name='SecondsToMSS' return='string' arguments='float fSecs'>
-		Converts <code>fSecs</code> to Minutes:Seconds.Milliseconds format using two digits for each section except Minutes (uses 1).
+		Converts <code>fSecs</code> to Minutes:Seconds format using one digit for Minutes and two digits for Seconds.
 	</Function>
 	<Function name='SecondsToMMSS' return='string' arguments='float fSecs'>
-		Converts <code>fSecs</code> to Minutes:Seconds format.
+		Converts <code>fSecs</code> to Minutes:Seconds format using two digits for both sections.
 	</Function>
 	<Function name='SecondsToMSSMsMs' return='string' arguments='float fSecs'>
-		Converts <code>fSecs</code> to Minutes:Seconds.Milliseconds format.
+		Converts <code>fSecs</code> to Minutes:Seconds.Milliseconds format using one digit for Minutes, two digits for Seconds, and two digits for Milliseconds.
 	</Function>
 	<Function name='SecondsToMMSSMsMs' return='string' arguments='float fSecs'>
 		Converts <code>fSecs</code> to Minutes:Seconds.Milliseconds format using two digits for each section.
 	</Function>
 	<Function name='SecondsToMMSSMsMsMs' return='string' arguments='float fSecs'>
-		Converts <code>fSecs</code> to Minutes:Seconds.Milliseconds format using two digits for each section except Milliseconds (uses 3).
+		Converts <code>fSecs</code> to Minutes:Seconds.Milliseconds format using two digits for Minutes, two digits for Seconds, and three digits for Milliseconds.
 	</Function>
 	<Function name='select' return='various' arguments='various index, ...'>
 		"If <code>index</code> is a number, returns all arguments after argument
@@ -819,8 +816,9 @@ save yourself some time, copy this for undocumented things:
 		If unsuccessful, it returns two values: <code>nil</code> and <code>"error"</code>.
 	</Function>
 	<Function name='ReportScriptError' return='void' arguments='string error, string error_type'>
-		Reports the error through the error reporting system.  error_type is the type used for the dialog that is presented, a dialog will not appear for a type the user has chosen to ignore.<br/>
-		error is optional an defaults to "Script error occurred.".  error_type is optional and defaults to "LUA_ERROR".
+		Reports the error through the error reporting system.<br/>
+		<code>error</code> is optional and defaults to "Script error occurred.".<br/>
+		<code>error_type</code> is optional and defaults to "LUA_ERROR".  Errors of type "LUA_ERROR" will be shown in-game if the <code>ShowThemeErrors</code> preference is enabled. A dialog will not appear for an <code>error_type</code> the user has chosen to ignore.
 	</Function>
 	<Function name='RunWithThreadVariables' return='int' arguments='function func, table t, ...'>
 		Calls <code>func(...)</code> with LuaThreadVariables set according to the keys and values of <code>t</code>, and returns the return values of <code>func()</code>.<br/>
@@ -1849,10 +1847,11 @@ save yourself some time, copy this for undocumented things:
 </Class>
 <Class name='ActorSound'>
 	<Description>
-		This Actor represents a playable sound. There are two attributes that can be set on load.<br />
-		* <code>SupportPan</code> - Let the sound pan from side to side.<br />
-		* <code>SupportRateChanging</code> - Let the sound change rate and pitch.<br />
-		* <code>IsAction</code> - If true, the sound is an action sound, and will be muted if the MuteActions preference is turned on.
+		This Actor represents a playable sound.  Though the C++ class is ActorSound, it is accessible to Lua via <code>Def.Sound</code>.<br/>
+		There are three attributes that can be set as booleans on load:<br />
+		• <code>SupportPan</code> - Let the sound pan from side to side.<br />
+		• <code>SupportRateChanging</code> - Let the sound change rate and pitch.<br />
+		• <code>IsAction</code> - If true, the sound is an action sound, and will be muted if the MuteActions preference is turned on.
 	</Description>
 	<Function name='get' return='RageSound' arguments=''>
 		Returns the <Link class='RageSound' /> that can be played by this Actor.
@@ -2128,7 +2127,7 @@ save yourself some time, copy this for undocumented things:
 		Returns the path to the Course's banner.
 	</Function>
 	<Function name='GetCourseDir' return='string' arguments=''>
-		Returns the Course's directory.
+		Returns the path to the crs file for this Course, for example "/Courses/Default/MostPlayed_01_04.crs".
 	</Function>
 	<Function name='GetCourseEntries' return='{CourseEntry}' arguments=''>
 		Returns a table of CourseEntry items.
@@ -2137,7 +2136,7 @@ save yourself some time, copy this for undocumented things:
 		Gets the CourseEntry at <code>iIndex</code> from the Course.
 	</Function>
 	<Function name='GetCourseType' renamed='true' return='CourseType' arguments=''>
-		Returns the Course's <Link class='ENUM' function='CourseType' />. (Returns CourseType in SM5; integer in SM4)
+		Returns the Course's <Link class='ENUM' function='CourseType' />.
 	</Function>
 	<Function name='GetDescription' return='string' arguments=''>
 		Returns the description for this Course.
@@ -2155,7 +2154,7 @@ save yourself some time, copy this for undocumented things:
 		Returns the Course's group name.
 	</Function>
 	<Function name='GetPlayMode' renamed='true' return='PlayMode' arguments=''>
-		Returns the Course's <Link class='ENUM' function='PlayMode' />. (Returns PlayMode in SM5; integer in SM4)
+		Returns the Course's <Link class='ENUM' function='PlayMode' />.
 	</Function>
 	<Function name='GetScripter' return='string' arguments=''>
 		Returns the name of the person who scripted the Course.
@@ -2771,8 +2770,8 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetPlayMode' return='PlayMode' arguments=''>
 		Returns the current PlayMode.
 	</Function>
-	<Function name='GetPreferredDifficulty' return='Difficulty' arguments=''>
-		Returns the preferred difficulty.
+	<Function name='GetPreferredDifficulty' return='Difficulty' arguments='PlayerNumber pn'>
+		Returns the preferred difficulty for player <code>pn</code>.
 	</Function>
 	<Function name='GetPreferredSong' return='Song' arguments=''>
 		Returns the preferred song.
@@ -3040,9 +3039,6 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetGrade' return='Grade' arguments=''>
 		Returns the Grade of this high score.
 	</Function>
-	<Function name='GetHighScore' return='HighScore' arguments=''>
-		Returns the HighScore for this PlayerStageStats.
-	</Function>
 	<Function name='GetHoldNoteScore' return='int' arguments='HoldNoteScore hns'>
 		Return the number of HoldNoteScores that match <code>hns</code>.
 	</Function>
@@ -3900,7 +3896,7 @@ save yourself some time, copy this for undocumented things:
 		Returns the player's grade.
 	</Function>
 	<Function name='GetHighScore' return='HighScore' arguments=''>
-		Returns the player's HighScore.
+		Returns the HighScore for this PlayerStageStats.
 	</Function>
 	<Function name='GetHoldNoteScores' return='int' arguments='HoldNoteScore hns'>
 		Returns the number of judgments for a specified HoldNoteScore.
@@ -4813,7 +4809,10 @@ save yourself some time, copy this for undocumented things:
 		Returns the profile index of the specified Player.
 	</Function>
 	<Function name='SetProfileIndex' return='bool' arguments='PlayerNumber pn, int iProfileIndex'>
-		Sets the profile index of Player <code>pn</code> to <code>iProfileIndex</code>.
+		Sets the profile index of Player <code>pn</code> to <code>iProfileIndex</code>.<br/>
+		The following values of <code>iProfileIndex</code> have special, hardcoded behavior:<br/>
+		• <code>-1</code>: join the player and play the theme's start sound effect<br/>
+		• <code>-2</code>: unjoin the player, unlock their MemoryCard, and unmount their MemoryCard
 	</Function>
 </Class>
 <Class name='ScreenTextEntry'>
@@ -5497,8 +5496,12 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetStyleType' return='StyleType' arguments=''>
 		Returns the StyleType for this Style.
 	</Function>
-	<Function name='GetColumnInfo' return='{int, int, string}' arguments='int column'>
-		Returns a table containing the Track, XOffset, and Name of the column.
+	<Function name='GetColumnInfo' return='{int, int, string}' arguments='PlayerNumber pn, int column'>
+		Returns a table containing the <code>Track</code>, <code>XOffset</code>, and <code>Name</code> of the column.<br/>
+		For example, calling <code>GAMESTATE:GetCurrentStyle():GetColumnInfo('PlayerNumber_P1', 2)</code> when the current
+		game is dance will return <code>{Track=2, XOffset=-32, Name="Down"}</code>.<br/>
+		Calling <code>GAMESTATE:GetCurrentStyle():GetColumnInfo('PlayerNumber_P1', 1)</code> when the current
+		game is pump will return <code>{Track=1, XOffset=-96, Name="DownLeft"}</code>.<br/>
 	</Function>
 	<Function name='GetColumnDrawOrder' return='int' arguments='int column'>
 		Returns the draw order of the column.

From 21eed3f23560dcab687363e307bfdba5b657ac03 Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Tue, 28 Apr 2020 22:47:54 -0400
Subject: [PATCH 18/65] add 21:9 and 9:16 to ConfAspectRatio in _fallback

This adds choices for 21:9 (Ultrawide) and 9:16 (widescreen display in
portrait mode) to the _fallback theme.  Previously, users would have to
manually edit Preferences.ini to achieve either of these.

Since "21:9" is the common marketing term for what is actually 64:27,
I've slightly extended GenChoices() in ConfAspectRatio() to use a "name"
string from the winFracs table is one is provided. If not, the original
behavior of generating user-facing choices from the raw values is
preserved.

See: https://wikipedia.org/wiki/21:9_aspect_ratio

I updated the global AspectRatios table in _fallback/02 Utilities.lua to
match.
---
 Themes/_fallback/Scripts/02 Utilities.lua    | 16 +++++++++-------
 Themes/_fallback/Scripts/03 DisplaySpecs.lua | 15 +++++++++------
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/Themes/_fallback/Scripts/02 Utilities.lua b/Themes/_fallback/Scripts/02 Utilities.lua
index da1f966b83..5a4d1ccc87 100644
--- a/Themes/_fallback/Scripts/02 Utilities.lua	
+++ b/Themes/_fallback/Scripts/02 Utilities.lua	
@@ -329,13 +329,15 @@ end
 
 -- supported aspect ratios
 AspectRatios = {
-	ThreeFour   = 0.75,		-- (576x760 at 1024x768; meant for rotated monitors?)
-	OneOne      = 1.0,		-- 480x480  (uses Y value of specified resolution)
-	FiveFour    = 1.25,		-- 600x480 (1280x1024 is a real use case)
-	FourThree   = 1.33333,	-- 640x480 (common)
-	SixteenTen  = 1.6,		-- 720x480 (common)
-	SixteenNine = 1.77778,	-- 853x480 (common)
-	EightThree  = 2.66666	-- 1280x480 (two monitors)
+	ThreeFour    = 0.75,    -- (576x760 at 1024x768; meant for rotated monitors?)
+	OneOne       = 1.0,     -- 480x480  (uses Y value of specified resolution)
+	FiveFour     = 1.25,    -- 600x480 (1280x1024 is a real use case)
+	FourThree    = 1.33333, -- 640x480 (common)
+	SixteenTen   = 1.6,     -- 720x480 (common)
+	SixteenNine  = 1.77778, -- 853x480 (common)
+	EightThree   = 2.66666, -- 1280x480 (two monitors)
+	TwentyOneNine= 2.37,    -- 1138x480 (Ultrawide)
+	NineSixteen  = 0.5625,  -- 480x720  (16:9 widescreen as portrait display)
 }
 
 function WideScale(AR4_3, AR16_9)
diff --git a/Themes/_fallback/Scripts/03 DisplaySpecs.lua b/Themes/_fallback/Scripts/03 DisplaySpecs.lua
index e8782fc5ad..2980f160bd 100644
--- a/Themes/_fallback/Scripts/03 DisplaySpecs.lua	
+++ b/Themes/_fallback/Scripts/03 DisplaySpecs.lua	
@@ -94,14 +94,17 @@ end
 
 -- TODO: here, I'm replicating the AspectRatios table from "02 Utilities.lua",
 -- but in a friendly format
+-- name can optionally be provided as a user-facing string for ConfAspectRatio
 local winFracs = {
-	{n=3, d=4},
-	{n=1, d=1},
-	{n=5, d=4},
-	{n=4, d=3},
+	{n=3,  d=4},
+	{n=1,  d=1},
+	{n=5,  d=4},
+	{n=4,  d=3},
 	{n=16, d=10},
 	{n=16, d=9},
-	{n=8, d=3}
+	{n=8,  d=3},
+	{n=64, d=27, name="21:9"},
+	{n=9,  d=16},
 }
 -- Maximum distance between aspect ratios to be considered equivalent
 -- (approximately half the distance between 16:9 and 16:10)
@@ -243,7 +246,7 @@ function ConfAspectRatio()
 			local vals = {}
 			foreach_ordered(ratios, function(v, f)
 						vals[#vals + 1] = f.n/f.d
-						choices[#choices + 1] = tostring(f.n) .. ':' .. tostring(f.d)
+						choices[#choices + 1] = (type(f.name)=="string" and f.name) or ("%d:%d"):format(f.n, f.d)
 			end)
 			self.Choices = choices
 			self.ChoiceVals = vals

From e16017bd1a7e6cfa105481b311a8df48b97c61c4 Mon Sep 17 00:00:00 2001
From: aeubanks <ayueubanks@gmail.com>
Date: Thu, 30 Apr 2020 13:24:23 -0700
Subject: [PATCH 19/65] Clean up InputHandler_SextetStream (#1985)

Before, this ended up calling a virtual method in the constructor,
which C++ does not allow, and I got weird crashes.

This removes a lot of unused code and gets rid of unnecessary abstractions.
---
 .../InputHandler_SextetStream.cpp             | 207 +++++-------------
 .../InputHandler/InputHandler_SextetStream.h  |  11 +-
 2 files changed, 59 insertions(+), 159 deletions(-)

diff --git a/src/arch/InputHandler/InputHandler_SextetStream.cpp b/src/arch/InputHandler/InputHandler_SextetStream.cpp
index e0cde24bdd..c91ac4e69e 100644
--- a/src/arch/InputHandler/InputHandler_SextetStream.cpp
+++ b/src/arch/InputHandler/InputHandler_SextetStream.cpp
@@ -33,22 +33,44 @@ namespace
 {
 	class LineReader
 	{
-		protected:
+		private:
+			// The buffer size isn't critical; the RString will simply be
+			// extended until the line is done.
+			static const size_t BUFFER_SIZE = 64;
+			char buffer[BUFFER_SIZE];
+			std::FILE * file;
 			int timeout_ms;
 
 		public:
-			LineReader()
+			LineReader(const RString& filename)
 			{
 				timeout_ms = DEFAULT_TIMEOUT_MS;
+
+				LOG->Info("Starting InputHandler_SextetStreamFromFile from std::FILE with filename '%s'",
+					filename.c_str());
+				file = std::fopen(filename.c_str(), "rb");
+
+				if(file == nullptr) {
+					LOG->Warn("Error opening file '%s' for input (cstdio): %s", filename.c_str(),
+						std::strerror(errno));
+				}
+				else {
+					LOG->Info("File opened");
+					// Disable buffering on the file
+					std::setbuf(file, nullptr);
+				}
 			}
 
-			virtual ~LineReader()
+			~LineReader()
 			{
+				if(file != nullptr) {
+					std::fclose(file);
+				}
 			}
 
-			virtual bool IsValid()
+			bool IsValid()
 			{
-				return false;
+				return file != nullptr;
 			}
 
 			// Ideally, this method should return if timeout_ms passes
@@ -74,7 +96,26 @@ namespace
 			// false (line undefined) if there is an error or EOF condition,
 			// true (line = next line from stream) if a whole line is available,
 			// true (line = "") if no error but still waiting for next line.
-			virtual bool ReadLine(RString& line) = 0;
+			bool ReadLine(RString& line)
+			{
+				bool afterFirst = false;
+				size_t len;
+
+				line = "";
+
+				if(file != nullptr) {
+					while(fgets(buffer, BUFFER_SIZE, file) != nullptr) {
+						afterFirst = true;
+						line += buffer;
+						len = line.length();
+						if(len > 0 && line[len - 1] == 0xA) {
+							break;
+						}
+					}
+				}
+
+				return afterFirst;
+			}
 	};
 }
 
@@ -82,6 +123,7 @@ class InputHandler_SextetStream::Impl
 {
 	private:
 		InputHandler_SextetStream * handler;
+		RString filename;
 
 	protected:
 		void ButtonPressed(const DeviceInput& di)
@@ -94,12 +136,6 @@ class InputHandler_SextetStream::Impl
 		RageThread inputThread;
 		bool continueInputThread;
 
-		// Construct and return the LineReader that makes sense for this
-		// object. getLineReader() calls this; if the returned object claims
-		// it is valid, it is returned. Otherwise, it is destroyed and nullptr
-		// is returned.
-		virtual LineReader * getUnvalidatedLineReader() = 0;
-
 		inline void clearStateBuffer()
 		{
 			memset(stateBuffer, 0, STATE_BUFFER_SIZE);
@@ -114,30 +150,29 @@ class InputHandler_SextetStream::Impl
 
 		LineReader * getLineReader()
 		{
-			LineReader * linereader = getUnvalidatedLineReader();
-			if(linereader != nullptr) {
-				if(!linereader->IsValid()) {
-					delete linereader;
-					linereader = nullptr;
-				}
+			LineReader * linereader = new LineReader(filename);
+			if(!linereader->IsValid()) {
+				delete linereader;
+				linereader = nullptr;
 			}
 			return linereader;
 		}
 
 	public:
-		Impl(InputHandler_SextetStream * _this)
+		Impl(InputHandler_SextetStream * _this, const RString& filename)
 		{
 			LOG->Info("Number of button states supported by current InputHandler_SextetStream: %u",
 				(unsigned)BUTTON_COUNT);
 			continueInputThread = false;
 			timeout_ms = DEFAULT_TIMEOUT_MS;
 
+			this->filename = filename;
 			handler = _this;
 			clearStateBuffer();
 			createThread();
 		}
 
-		virtual ~Impl()
+		~Impl()
 		{
 			if(inputThread.IsCreated()) {
 				continueInputThread = false;
@@ -145,7 +180,7 @@ class InputHandler_SextetStream::Impl
 			}
 		}
 
-		virtual void GetDevicesAndDescriptions(vector<InputDeviceInfo>& vDevicesOut)
+		void GetDevicesAndDescriptions(vector<InputDeviceInfo>& vDevicesOut)
 		{
 			vDevicesOut.push_back(InputDeviceInfo(FIRST_DEVICE, "SextetStream"));
 		}
@@ -287,137 +322,9 @@ REGISTER_INPUT_HANDLER_CLASS (SextetStreamFromFile);
 #endif
 static Preference<RString> g_sSextetStreamInputFilename("SextetStreamInputFilename", DEFAULT_INPUT_FILENAME);
 
-namespace
-{
-	class StdCFileLineReader: public LineReader
-	{
-		private:
-			// The buffer size isn't critical; the RString will simply be
-			// extended until the line is done.
-			static const size_t BUFFER_SIZE = 64;
-			char buffer[BUFFER_SIZE];
-		protected:
-			std::FILE * file;
-
-		public:
-			StdCFileLineReader(std::FILE * file)
-			{
-				LOG->Info("Starting InputHandler_SextetStreamFromFile from open std::FILE");
-				this->file = file;
-			}
-
-			StdCFileLineReader(const RString& filename)
-			{
-				LOG->Info("Starting InputHandler_SextetStreamFromFile from std::FILE with filename '%s'",
-					filename.c_str());
-				file = std::fopen(filename.c_str(), "rb");
-
-				if(file == nullptr) {
-					LOG->Warn("Error opening file '%s' for input (cstdio): %s", filename.c_str(),
-						std::strerror(errno));
-				}
-				else {
-					LOG->Info("File opened");
-					// Disable buffering on the file
-					std::setbuf(file, nullptr);
-				}
-			}
-
-			~StdCFileLineReader()
-			{
-				if(file != nullptr) {
-					std::fclose(file);
-				}
-			}
-
-			virtual bool IsValid()
-			{
-				return file != nullptr;
-			}
-
-			virtual bool ReadLine(RString& line)
-			{
-				bool afterFirst = false;
-				size_t len;
-
-				line = "";
-
-				if(file != nullptr) {
-					while(fgets(buffer, BUFFER_SIZE, file) != nullptr) {
-						afterFirst = true;
-						line += buffer;
-						len = line.length();
-						if(len > 0 && line[len - 1] == 0xA) {
-							break;
-						}
-					}
-				}
-
-				return afterFirst;
-			}
-	};
-
-	class StdCFileHandleImpl: public InputHandler_SextetStream::Impl
-	{
-		protected:
-			std::FILE * file;
-
-		public:
-			StdCFileHandleImpl(InputHandler_SextetStreamFromFile * handler, std::FILE * file) :
-				InputHandler_SextetStream::Impl(handler)
-			{
-				this->file = file;
-			}
-
-			virtual LineReader * getUnvalidatedLineReader()
-			{
-				return new StdCFileLineReader(this->file);
-			}
-
-			virtual ~StdCFileHandleImpl()
-			{
-				// line reader dtor will close file for us
-			}
-	};
-
-	class StdCFileNameImpl: public InputHandler_SextetStream::Impl
-	{
-		protected:
-			RString filename;
-
-		public:
-			StdCFileNameImpl(InputHandler_SextetStreamFromFile * handler, const RString& filename) :
-				InputHandler_SextetStream::Impl(handler)
-			{
-				this->filename = filename;
-			}
-
-			virtual LineReader * getUnvalidatedLineReader()
-			{
-				return new StdCFileLineReader(filename);
-			}
-
-			virtual ~StdCFileNameImpl()
-			{
-				// Nothing to destroy
-			}
-	};
-}
-
-
-InputHandler_SextetStreamFromFile::InputHandler_SextetStreamFromFile(FILE * file)
-{
-	_impl = new StdCFileHandleImpl(this, file);
-}
-
-InputHandler_SextetStreamFromFile::InputHandler_SextetStreamFromFile(const RString& filename)
-{
-	_impl = new StdCFileNameImpl(this, filename);
-}
-
 InputHandler_SextetStreamFromFile::InputHandler_SextetStreamFromFile()
 {
-	_impl = new StdCFileNameImpl(this, g_sSextetStreamInputFilename);
+	_impl = new Impl(this, g_sSextetStreamInputFilename);
 }
 
 /*
diff --git a/src/arch/InputHandler/InputHandler_SextetStream.h b/src/arch/InputHandler/InputHandler_SextetStream.h
index ee019cd1ea..b0b3748fde 100644
--- a/src/arch/InputHandler/InputHandler_SextetStream.h
+++ b/src/arch/InputHandler/InputHandler_SextetStream.h
@@ -8,9 +8,8 @@ class InputHandler_SextetStream: public InputHandler
 {
 public:
 	InputHandler_SextetStream();
-	virtual ~InputHandler_SextetStream();
-	//virtual void Update();
-	virtual void GetDevicesAndDescriptions(vector<InputDeviceInfo>& vDevicesOut);
+	~InputHandler_SextetStream();
+	void GetDevicesAndDescriptions(vector<InputDeviceInfo>& vDevicesOut);
 
 public:
 	class Impl;
@@ -36,12 +35,6 @@ public:
 	// couldn't get RageFile to work here, possibly because I haven't
 	// determined how to disable buffering on an input file.) 
 	InputHandler_SextetStreamFromFile();
-	InputHandler_SextetStreamFromFile(const RString& filename);
-
-	// The file object passed here must already be open and buffering should
-	// be disabled. The file object will be closed in the destructor.
-	InputHandler_SextetStreamFromFile(std::FILE * file);
-
 };
 
 #endif

From bbafb49b3a151b6434bf825c1240df41b7ee85ff Mon Sep 17 00:00:00 2001
From: aeubanks <ayueubanks@gmail.com>
Date: Thu, 30 Apr 2020 13:24:58 -0700
Subject: [PATCH 20/65] Don't force libc++ with clang (#1984)

Clang works with libstdc++.
---
 extern/CMakeProject-cppformat.cmake | 3 ---
 extern/CMakeProject-json.cmake      | 3 ---
 src/CMakeData-gtk.cmake             | 4 ----
 src/CMakeLists.txt                  | 6 ------
 4 files changed, 16 deletions(-)

diff --git a/extern/CMakeProject-cppformat.cmake b/extern/CMakeProject-cppformat.cmake
index 37309e099e..dc63134864 100644
--- a/extern/CMakeProject-cppformat.cmake
+++ b/extern/CMakeProject-cppformat.cmake
@@ -32,7 +32,4 @@ elseif(APPLE)
   sm_add_compile_flag("cppformat" "-stdlib=libc++")
 else() # Unix
   sm_add_compile_flag("cppformat" "-std=${SM_CPP_STANDARD}")
-  if(CMAKE_CXX_COMPILER MATCHES "clang")
-    sm_add_compile_flag("cppformat" "-stdlib=libc++")
-  endif()
 endif()
diff --git a/extern/CMakeProject-json.cmake b/extern/CMakeProject-json.cmake
index ed149904fb..ec133ea2be 100644
--- a/extern/CMakeProject-json.cmake
+++ b/extern/CMakeProject-json.cmake
@@ -40,8 +40,5 @@ else()
     sm_add_compile_flag("jsoncpp" "-stdlib=libc++")
   else() # Unix/Linux
     sm_add_compile_flag("jsoncpp" "-std=gnu++11")
-    if(CMAKE_CXX_COMPILER MATCHES "clang")
-      sm_add_compile_flag("jsoncpp" "-stdlib=libc++")
-    endif()
   endif()
 endif()
diff --git a/src/CMakeData-gtk.cmake b/src/CMakeData-gtk.cmake
index 87946873de..10f9ea6b83 100644
--- a/src/CMakeData-gtk.cmake
+++ b/src/CMakeData-gtk.cmake
@@ -8,10 +8,6 @@ add_library("GtkModule"
             "arch/LoadingWindow/LoadingWindow_GtkModule.h")
 
 sm_add_compile_flag("GtkModule" "-std=${SM_CPP_STANDARD}")
-if(CMAKE_CXX_COMPILER MATCHES "clang")
-  sm_add_compile_flag("GtkModule" "-stdlib=libc++")
-  set_target_properties("GtkModule" PROPERTIES LINK_FLAGS "-stdlib=libc++")
-endif()
 
 # It is normally not appropriate to set the prefix to the empty string. This is
 # to maintain compatibility with the current source. At some point, it may be
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index aadde32fd7..f772ae3123 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -390,12 +390,6 @@ else() # Linux
   endif()
 
   sm_add_compile_flag("${SM_EXE_NAME}" "-std=${SM_CPP_STANDARD}")
-  if(CMAKE_CXX_COMPILER MATCHES "clang")
-    sm_add_compile_flag("${SM_EXE_NAME}" "-stdlib=libc++")
-    set_target_properties("${SM_EXE_NAME}"
-                          PROPERTIES LINK_FLAGS "-stdlib=libc++")
-    sm_add_compile_flag("jsoncpp" "-stdlib=libc++")
-  endif()
 endif()
 
 set_property(TARGET "${SM_EXE_NAME}" PROPERTY FOLDER "Internal Libraries")

From e799b292daedbcfd9985893f517a340b2b714532 Mon Sep 17 00:00:00 2001
From: din <dinsfire64@gmail.com>
Date: Fri, 8 May 2020 19:49:40 -0500
Subject: [PATCH 21/65] ITGIO Support for Linux

---
 src/CMakeData-arch.cmake                     |   2 +
 src/arch/Lights/LightsDriver_Linux_ITGIO.cpp | 157 +++++++++++++++++++
 src/arch/Lights/LightsDriver_Linux_ITGIO.h   |  46 ++++++
 3 files changed, 205 insertions(+)
 create mode 100644 src/arch/Lights/LightsDriver_Linux_ITGIO.cpp
 create mode 100644 src/arch/Lights/LightsDriver_Linux_ITGIO.h

diff --git a/src/CMakeData-arch.cmake b/src/CMakeData-arch.cmake
index f39517f300..896506fb50 100644
--- a/src/CMakeData-arch.cmake
+++ b/src/CMakeData-arch.cmake
@@ -230,11 +230,13 @@ if(NOT APPLE)
       list(APPEND SMDATA_ARCH_LIGHTS_SRC
                   "arch/Lights/LightsDriver_Linux_PIUIO.cpp"
                   "arch/Lights/LightsDriver_Linux_PIUIO_Leds.cpp"
+                  "arch/Lights/LightsDriver_Linux_ITGIO.cpp"
                   "arch/Lights/LightsDriver_LinuxWeedTech.cpp"
                   "arch/Lights/LightsDriver_LinuxParallel.cpp")
       list(APPEND SMDATA_ARCH_LIGHTS_HPP
                   "arch/Lights/LightsDriver_Linux_PIUIO.h"
                   "arch/Lights/LightsDriver_Linux_PIUIO_Leds.h"
+                  "arch/Lights/LightsDriver_Linux_ITGIO.h"
                   "arch/Lights/LightsDriver_LinuxWeedTech.h"
                   "arch/Lights/LightsDriver_LinuxParallel.h")
       if(WITH_PARALLEL_PORT)
diff --git a/src/arch/Lights/LightsDriver_Linux_ITGIO.cpp b/src/arch/Lights/LightsDriver_Linux_ITGIO.cpp
new file mode 100644
index 0000000000..21c4ab6c2b
--- /dev/null
+++ b/src/arch/Lights/LightsDriver_Linux_ITGIO.cpp
@@ -0,0 +1,157 @@
+#include "global.h"
+#include <stdio.h>
+#if defined(HAVE_UNISTD_H)
+#include <unistd.h>
+#endif
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#if defined(HAVE_FCNTL_H)
+#include <fcntl.h>
+#endif
+
+#include <errno.h>
+#include "LightsDriver_Linux_ITGIO.h"
+#include "GameState.h"
+#include "Game.h"
+#include "RageLog.h"
+
+REGISTER_LIGHTS_DRIVER_CLASS2(ITGIO, Linux_ITGIO);
+
+//NOTE: light index 14 is not mapped, this is the coin drop "light"
+
+namespace {
+	const char *cabinet_leds[NUM_CabinetLight] = {
+		//UL, UR, LL, LR, Bass L, Bass R
+		"/sys/class/leds/itgio::output8/brightness",
+		"/sys/class/leds/itgio::output10/brightness",
+		"/sys/class/leds/itgio::output9/brightness",
+		"/sys/class/leds/itgio::output11/brightness",
+		"/sys/class/leds/itgio::output15/brightness",
+		"/sys/class/leds/itgio::output15/brightness",
+	};
+
+	const char *dance_leds[NUM_GameController][NUM_GameButton] = {
+		{
+			nullptr, nullptr, nullptr, nullptr,
+			//player start
+			"/sys/class/leds/itgio::output13/brightness",
+			nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
+			//left right up down
+			"/sys/class/leds/itgio::output1/brightness",
+			"/sys/class/leds/itgio::output0/brightness",
+			"/sys/class/leds/itgio::output3/brightness",
+			"/sys/class/leds/itgio::output2/brightness",
+		},
+		{
+			nullptr, nullptr, nullptr, nullptr,
+			//player start
+			"/sys/class/leds/itgio::output12/brightness",
+			nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
+			//left right up down
+			"/sys/class/leds/itgio::output5/brightness",
+			"/sys/class/leds/itgio::output4/brightness",
+			"/sys/class/leds/itgio::output7/brightness",
+			"/sys/class/leds/itgio::output6/brightness",
+		},
+	};
+
+	bool SetLight(const char *filename, bool on)
+	{
+		if (filename == nullptr)
+			return true;
+		FILE *f = fopen(filename, "w");
+		if (f == nullptr)
+		{
+			return false;
+		}
+		fprintf(f, "%d", on ? 255 : 0);
+		fclose(f);
+		return true;
+	}
+}
+
+LightsDriver_Linux_ITGIO::LightsDriver_Linux_ITGIO()
+{
+}
+
+LightsDriver_Linux_ITGIO::~LightsDriver_Linux_ITGIO()
+{
+}
+
+void LightsDriver_Linux_ITGIO::SetGameControllerLight(const LightsState *ls, GameController c, GameButton gb)
+{
+	//only push a change in the light iff it's an actual change.
+	if (ls->m_bGameButtonLights[c][gb] == previousLS.m_bGameButtonLights[c][gb])
+	{
+		return;
+	}
+
+	if (!SetLight(dance_leds[c][gb], ls->m_bGameButtonLights[c][gb]))
+	{
+		//grab the game info for a proper debug log.
+		const InputScheme *pInput = &GAMESTATE->GetCurrentGame()->m_InputScheme;
+		RString sInputName = pInput->m_szName;
+
+		LOG->Warn("Error setting button light %s", GameButtonToString(pInput, gb).c_str());
+	}
+}
+
+void LightsDriver_Linux_ITGIO::Set( const LightsState *ls )
+{
+	FOREACH_CabinetLight(light)
+	{
+		// Only SetLight if LightsState has changed since previous iteration.
+		// This reduces unncessary strain on udev.  -dguzek
+		if (ls->m_bCabinetLights[light] == previousLS.m_bCabinetLights[light] )
+		{
+			continue;
+		}
+
+		if (!SetLight(cabinet_leds[light], ls->m_bCabinetLights[light]))
+		{
+			LOG->Warn("Error setting cabinet light %s",
+					CabinetLightToString(light).c_str());
+			return;
+		}
+	}
+
+	FOREACH_ENUM(GameController, c)
+	{
+		//takes care of each of the player buttons (UDLR)
+		FOREACH_GameButton_Custom(gb)
+		{
+			SetGameControllerLight(ls, c, gb);
+		}
+
+		//Takes care of the cabinet based player lights.
+		SetGameControllerLight(ls, c, GAME_BUTTON_START);
+	}
+
+	previousLS = *ls;
+}
+
+/*
+ * (c) 2020 StepMania team
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, and/or sell copies of the Software, and to permit persons to
+ * whom the Software is furnished to do so, provided that the above
+ * copyright notice(s) and this permission notice appear in all copies of
+ * the Software and that both the above copyright notice(s) and this
+ * permission notice appear in supporting documentation.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
+ * THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
+ * INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
+ * OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
diff --git a/src/arch/Lights/LightsDriver_Linux_ITGIO.h b/src/arch/Lights/LightsDriver_Linux_ITGIO.h
new file mode 100644
index 0000000000..b5131b05ec
--- /dev/null
+++ b/src/arch/Lights/LightsDriver_Linux_ITGIO.h
@@ -0,0 +1,46 @@
+/* LightsDriver_Linux_ITGIO: Control ITGIO lights via /sys/class/leds */
+
+#ifndef LightsDriver_Linux_ITGIO_H
+#define LightsDriver_Linux_ITGIO_H
+
+#include "arch/Lights/LightsDriver.h"
+
+class LightsDriver_Linux_ITGIO : public LightsDriver
+{
+private:
+	LightsState previousLS;
+	void SetGameControllerLight(const LightsState *ls, GameController c, GameButton gb);
+
+public:
+	LightsDriver_Linux_ITGIO();
+	virtual ~LightsDriver_Linux_ITGIO();
+
+	virtual void Set( const LightsState *ls );
+};
+
+#endif
+
+/*
+ * (c) 2020 StepMania team
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, and/or sell copies of the Software, and to permit persons to
+ * whom the Software is furnished to do so, provided that the above
+ * copyright notice(s) and this permission notice appear in all copies of
+ * the Software and that both the above copyright notice(s) and this
+ * permission notice appear in supporting documentation.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
+ * THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
+ * INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
+ * OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */

From a892cbc4dd8d16bbdbb800159c404b0a52239f1d Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Mon, 11 May 2020 05:59:08 -0400
Subject: [PATCH 22/65] update Classes and Enums in bundled Lua.xml

This updates Actor classes, class methods, and Enums listed in the
bundled copy of Lua.xml to be current.

I used the command-line arg --ExportLuaInformation, to generate a wholly
new file, then manually removed some methods (e.g. literally numbered
PlayerOptions methods ported from notitg, CamelCase aliases of
spline-related methods) to keep previous manual modifications intact.

This doesn't touch GlobalFunctions in Lua.xml; those need further
review.
---
 Docs/Luadoc/Lua.xml | 105 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 88 insertions(+), 17 deletions(-)

diff --git a/Docs/Luadoc/Lua.xml b/Docs/Luadoc/Lua.xml
index 11d9021434..0cc660c3ce 100644
--- a/Docs/Luadoc/Lua.xml
+++ b/Docs/Luadoc/Lua.xml
@@ -414,6 +414,7 @@
 			<Function name='rotationy'/>
 			<Function name='rotationz'/>
 			<Function name='scale_or_crop_background'/>
+			<Function name='scale_or_crop_background_no_move'/>
 			<Function name='scaletocover'/>
 			<Function name='scaletofit'/>
 			<Function name='setsize'/>
@@ -571,6 +572,7 @@
 			<Function name='SetTransformFromFunction'/>
 			<Function name='SetTransformFromHeight'/>
 			<Function name='SetTransformFromWidth'/>
+			<Function name='SetWrap'/>
 			<Function name='getsecondtodestination'/>
 			<Function name='scrollthroughallitems'/>
 			<Function name='scrollwithpadding'/>
@@ -580,10 +582,12 @@
 		</Class>
 		<Class base='Actor' name='ActorSound'>
 			<Function name='get'/>
+			<Function name='get_is_action'/>
 			<Function name='load'/>
 			<Function name='pause'/>
 			<Function name='play'/>
 			<Function name='playforplayer'/>
+			<Function name='set_is_action'/>
 			<Function name='stop'/>
 		</Class>
 		<Class name='AnnouncerManager'>
@@ -604,7 +608,6 @@
 			<Function name='SetFromSteps'/>
 		</Class>
 		<Class base='Sprite' name='Banner'>
-			<Function name='GetDecodeMovie'/>
 			<Function name='GetPercentScrolling'/>
 			<Function name='GetScrolling'/>
 			<Function name='LoadBackgroundFromUnlockEntry'/>
@@ -617,7 +620,6 @@
 			<Function name='LoadFromSortOrder'/>
 			<Function name='LoadIconFromCharacter'/>
 			<Function name='ScaleToClipped'/>
-			<Function name='SetDecodeMovie'/>
 			<Function name='SetScrolling'/>
 			<Function name='scaletoclipped'/>
 		</Class>
@@ -631,6 +633,7 @@
 			<Function name='Stroke'/>
 			<Function name='distort'/>
 			<Function name='get_mult_attrs_with_diffuse'/>
+			<Function name='getstrokecolor'/>
 			<Function name='jitter'/>
 			<Function name='max_dimension_use_zoom'/>
 			<Function name='maxheight'/>
@@ -669,6 +672,10 @@
 			<Function name='Load'/>
 			<Function name='Set'/>
 		</Class>
+		<Class base='ActorFrame' name='ControllerStateDisplay'>
+			<Function name='LoadGameController'/>
+			<Function name='LoadMultiPlayer'/>
+		</Class>
 		<Class name='Course'>
 			<Function name='AllSongsAreFixed'/>
 			<Function name='GetAllTrails'/>
@@ -683,6 +690,7 @@
 			<Function name='GetEstimatedNumStages'/>
 			<Function name='GetGoalSeconds'/>
 			<Function name='GetGroupName'/>
+			<Function name='GetNumCourseEntries'/>
 			<Function name='GetPlayMode'/>
 			<Function name='GetScripter'/>
 			<Function name='GetTotalSeconds'/>
@@ -842,6 +850,7 @@
 			<Function name='Dopefish'/>
 			<Function name='EnoughCreditsToJoin'/>
 			<Function name='Env'/>
+			<Function name='GetAutoGenFarg'/>
 			<Function name='GetCharacter'/>
 			<Function name='GetCoinMode'/>
 			<Function name='GetCoins'/>
@@ -870,6 +879,7 @@
 			<Function name='GetGameplayLeadIn'/>
 			<Function name='GetHardestStepsDifficulty'/>
 			<Function name='GetHumanPlayers'/>
+			<Function name='GetLastGameplayDuration'/>
 			<Function name='GetLoadingCourseSongIndex'/>
 			<Function name='GetMasterPlayerNumber'/>
 			<Function name='GetMultiPlayerState'/>
@@ -931,6 +941,7 @@
 			<Function name='ResetPlayerOptions'/>
 			<Function name='SaveLocalData'/>
 			<Function name='SaveProfiles'/>
+			<Function name='SetAutoGenFarg'/>
 			<Function name='SetCharacter'/>
 			<Function name='SetCurrentCourse'/>
 			<Function name='SetCurrentPlayMode'/>
@@ -946,10 +957,12 @@
 			<Function name='SetPreferredSong'/>
 			<Function name='SetPreferredSongGroup'/>
 			<Function name='SetSongOptions'/>
+			<Function name='SetStepsForEditMode'/>
 			<Function name='SetTemporaryEventMode'/>
 			<Function name='ShowW1'/>
 			<Function name='StoreRankingName'/>
 			<Function name='UnjoinPlayer'/>
+			<Function name='prepare_song_for_gameplay'/>
 		</Class>
 		<Class base='ActorFrame' name='GradeDisplay'>
 			<Function name='Load'/>
@@ -1049,6 +1062,7 @@
 			<Function name='ChangeSort'/>
 			<Function name='GetSelectedSection'/>
 			<Function name='IsRouletting'/>
+			<Function name='Move'/>
 			<Function name='SelectCourse'/>
 			<Function name='SelectSong'/>
 		</Class>
@@ -1120,6 +1134,8 @@
 			<Function name='GetPlayerTimingData'/>
 			<Function name='SetActorWithComboPosition'/>
 			<Function name='SetActorWithJudgmentPosition'/>
+			<Function name='get_oitg_zoom_mode'/>
+			<Function name='set_oitg_zoom_mode'/>
 		</Class>
 		<Class name='PlayerInfo'>
 			<Function name='GetLifeMeter'/>
@@ -1209,6 +1225,7 @@
 			<Function name='FailSetting'/>
 			<Function name='Flip'/>
 			<Function name='Floored'/>
+			<Function name='FromString'/>
 			<Function name='GetReversePercentForColumn'/>
 			<Function name='GetStepAttacks'/>
 			<Function name='IsEasierForSongAndSteps'/>
@@ -1458,6 +1475,7 @@
 			<Function name='SetLastUsedHighScoreName'/>
 			<Function name='SetWeightPounds'/>
 			<Function name='SetVoomax'/>
+			<Function name='get_songs'/>
 		</Class>
 		<Class name='ProfileManager'>
 			<Function name='GetLocalProfile'/>
@@ -1556,6 +1574,7 @@
 			<Function name='GetImageHeight'/>
 			<Function name='GetPath'/>
 			<Function name='GetTextureCoordRect'/>
+			<Function name='GetNumFrames'/>
 			<Function name='loop'/>
 			<Function name='position'/>
 			<Function name='rate'/>
@@ -1569,6 +1588,9 @@
 			<Function name='Load'/>
 			<Function name='targetnumber'/>
 		</Class>
+		<Class base='WheelBase' name='RoomWheel'>
+			<Function name='Move'/>
+		</Class>
 		<Class base='BitmapText' name='ScoreDisplayAliveTime'/>
 		<Class base='BitmapText' name='ScoreDisplayCalories'/>
 		<Class base='ActorFrame' name='Screen'>
@@ -1639,6 +1661,28 @@
 		<Class base='ScreenEvaluation' name='ScreenNetEvaluation'>
 			<Function name='GetNumActivePlayers'/>
 		</Class>
+		<Class base='ScreenNetSelectBase' name='ScreenNetRoom'>
+			<Function name='GetMusicWheel'/>
+			<Function name='SelectCurrent'/>
+		</Class>
+		<Class base='ScreenWithMenuElements' name='ScreenNetSelectBase'>
+			<Function name='ChatboxInput'/>
+			<Function name='ChatboxVisible'/>
+			<Function name='GetChatLines'/>
+			<Function name='GetChatScroll'/>
+			<Function name='GetUser'/>
+			<Function name='GetUserQty'/>
+			<Function name='GetUserState'/>
+			<Function name='ScrollChatDown'/>
+			<Function name='ScrollChatUp'/>
+			<Function name='ShowNextMsg'/>
+			<Function name='ShowPreviousMsg'/>
+			<Function name='UsersVisible'/>
+		</Class>
+		<Class base='ScreenNetSelectBase' name='ScreenNetSelectMusic'>
+			<Function name='GetMusicWheel'/>
+			<Function name='SelectCurrent'/>
+		</Class>
 		<Class base='ScreenWithMenuElements' name='ScreenOptions'>
 			<Function name='AllAreOnLastRow'/>
 			<Function name='FocusedItemEndsScreen'/>
@@ -1738,6 +1782,7 @@
 			<Function name='HasSignificantBPMChangesOrStops'/>
 			<Function name='HasStepsType'/>
 			<Function name='HasStepsTypeAndDifficulty'/>
+			<Function name='IsCustomSong'/>
 			<Function name='IsDisplayBpmConstant'/>
 			<Function name='IsDisplayBpmRandom'/>
 			<Function name='IsDisplayBpmSecret'/>
@@ -1749,6 +1794,7 @@
 			<Function name='IsTutorial'/>
 			<Function name='MusicLengthSeconds'/>
 			<Function name='NormallyDisplayed'/>
+			<Function name='ReloadFromSongDir'/>
 			<Function name='ShowInDemonstrationAndRanking'/>
 		</Class>
 		<Class name='SongManager'>
@@ -1818,6 +1864,7 @@
 		<Class base='Actor' name='Sprite'>
 			<Function name='CropTo'/>
 			<Function name='GetAnimationLengthSeconds'/>
+			<Function name='GetDecodeMovie'/>
 			<Function name='GetNumStates'/>
 			<Function name='GetState'/>
 			<Function name='GetTexture'/>
@@ -1832,6 +1879,7 @@
 			<Function name='SetAllStateDelays'/>
 			<Function name='SetCustomImageRect'/>
 			<Function name='SetCustomPosCoords'/>
+			<Function name='SetDecodeMovie'/>
 			<Function name='SetEffectMode'/>
 			<Function name='SetSecondsIntoAnimation'/>
 			<Function name='SetStateProperties'/>
@@ -1979,6 +2027,7 @@
 			<Function name='ReloadMetrics'/>
 			<Function name='RunLuaScripts'/>
 			<Function name='SetTheme'/>
+			<Function name='get_theme_fallback_list'/>
 		</Class>
 		<Class name='TimingData'>
 			<Function name='GetActualBPM'/>
@@ -2193,11 +2242,12 @@
 			<EnumValue name='&apos;AutosyncType_Machine&apos;' value='2'/>
 			<EnumValue name='&apos;AutosyncType_Tempo&apos;' value='3'/>
 		</Enum>
-		<Enum name='BannerCacheMode'>
-			<EnumValue name='&apos;BannerCacheMode_Off&apos;' value='0'/>
-			<EnumValue name='&apos;BannerCacheMode_LowResPreload&apos;' value='1'/>
-			<EnumValue name='&apos;BannerCacheMode_LowResLoadOnDemand&apos;' value='2'/>
-			<EnumValue name='&apos;BannerCacheMode_Full&apos;' value='3'/>
+		<Enum name='BackgroundFitMode'>
+			<EnumValue name='&apos;BackgroundFitMode_CoverDistort&apos;' value='0'/>
+			<EnumValue name='&apos;BackgroundFitMode_CoverPreserve&apos;' value='1'/>
+			<EnumValue name='&apos;BackgroundFitMode_FitInside&apos;' value='2'/>
+			<EnumValue name='&apos;BackgroundFitMode_FitInsideAvoidLetter&apos;' value='3'/>
+			<EnumValue name='&apos;BackgroundFitMode_FitInsideAvoidPillar&apos;' value='4'/>
 		</Enum>
 		<Enum name='BlendMode'>
 			<EnumValue name='&apos;BlendMode_Normal&apos;' value='0'/>
@@ -2294,6 +2344,7 @@
 			<EnumValue name='&apos;FileType_Xml&apos;' value='5'/>
 			<EnumValue name='&apos;FileType_Model&apos;' value='6'/>
 			<EnumValue name='&apos;FileType_Lua&apos;' value='7'/>
+			<EnumValue name='&apos;FileType_Ini&apos;' value='8'/>
 		</Enum>
 		<Enum name='GameController'>
 			<EnumValue name='&apos;GameController_1&apos;' value='0'/>
@@ -2361,6 +2412,12 @@
 			<EnumValue name='&apos;HorizAlign_Center&apos;' value='1'/>
 			<EnumValue name='&apos;HorizAlign_Right&apos;' value='2'/>
 		</Enum>
+		<Enum name='ImageCacheMode'>
+			<EnumValue name='&apos;ImageCacheMode_Off&apos;' value='0'/>
+			<EnumValue name='&apos;ImageCacheMode_LowResPreload&apos;' value='1'/>
+			<EnumValue name='&apos;ImageCacheMode_LowResLoadOnDemand&apos;' value='2'/>
+			<EnumValue name='&apos;ImageCacheMode_Full&apos;' value='3'/>
+		</Enum>
 		<Enum name='InputEventType'>
 			<EnumValue name='&apos;InputEventType_FirstPress&apos;' value= '0'/>
 			<EnumValue name='&apos;InputEventType_Repeat&apos;' value= '1'/>
@@ -2402,6 +2459,10 @@
 			<EnumValue name='&apos;Maybe_No&apos;' value='1'/>
 			<EnumValue name='&apos;Maybe_Yes&apos;' value='2'/>
 		</Enum>
+		<Enum name='MemoryCardDriverType'>
+			<EnumValue name='&apos;MemoryCardDriverType_USB&apos;' value='0'/>
+			<EnumValue name='&apos;MemoryCardDriverType_Directory&apos;' value='1'/>
+		</Enum>
 		<Enum name='MemoryCardState'>
 			<EnumValue name='&apos;MemoryCardState_ready&apos;' value='0'/>
 			<EnumValue name='&apos;MemoryCardState_checking&apos;' value='1'/>
@@ -2475,6 +2536,11 @@
 			<EnumValue name='&apos;MusicWheelUsesSections_Always&apos;' value='1'/>
 			<EnumValue name='&apos;MusicWheelUsesSections_ABCOnly&apos;' value='2'/>
 		</Enum>
+		<Enum name='NoteColorType'>
+			<EnumValue name='&apos;NoteColorType_Denominator&apos;' value='0'/>
+			<EnumValue name='&apos;NoteColorType_Progress&apos;' value='1'/>
+			<EnumValue name='&apos;NoteColorType_ProgressAlternate&apos;' value='2'/>
+		</Enum>
 		<Enum name='NoteColumnSplineMode'>
 			<EnumValue name='&apos;NoteColumnSplineMode_Disabled&apos;' value='0'/>
 			<EnumValue name='&apos;NoteColumnSplineMode_Offset&apos;' value='1'/>
@@ -2574,14 +2640,15 @@
 			<EnumValue name='&apos;RadarCategory_Air&apos;' value='2'/>
 			<EnumValue name='&apos;RadarCategory_Freeze&apos;' value='3'/>
 			<EnumValue name='&apos;RadarCategory_Chaos&apos;' value='4'/>
-			<EnumValue name='&apos;RadarCategory_TapsAndHolds&apos;' value='5'/>
-			<EnumValue name='&apos;RadarCategory_Jumps&apos;' value='6'/>
-			<EnumValue name='&apos;RadarCategory_Holds&apos;' value='7'/>
-			<EnumValue name='&apos;RadarCategory_Mines&apos;' value='8'/>
-			<EnumValue name='&apos;RadarCategory_Hands&apos;' value='9'/>
-			<EnumValue name='&apos;RadarCategory_Rolls&apos;' value='10'/>
-			<EnumValue name='&apos;RadarCategory_Lifts&apos;' value='11'/>
-			<EnumValue name='&apos;RadarCategory_Fakes&apos;' value='12'/>
+			<EnumValue name='&apos;RadarCategory_Notes&apos;' value='5'/>
+			<EnumValue name='&apos;RadarCategory_TapsAndHolds&apos;' value='6'/>
+			<EnumValue name='&apos;RadarCategory_Jumps&apos;' value='7'/>
+			<EnumValue name='&apos;RadarCategory_Holds&apos;' value='8'/>
+			<EnumValue name='&apos;RadarCategory_Mines&apos;' value='9'/>
+			<EnumValue name='&apos;RadarCategory_Hands&apos;' value='10'/>
+			<EnumValue name='&apos;RadarCategory_Rolls&apos;' value='11'/>
+			<EnumValue name='&apos;RadarCategory_Lifts&apos;' value='12'/>
+			<EnumValue name='&apos;RadarCategory_Fakes&apos;' value='13'/>
 		</Enum>
 		<Enum name='RandomBackgroundMode'>
 			<EnumValue name='&apos;RandomBackgroundMode_Off&apos;' value='0'/>
@@ -2726,6 +2793,10 @@
 			<EnumValue name='&apos;StepsType_Pnm_Five&apos;' value='31'/>
 			<EnumValue name='&apos;StepsType_Pnm_Nine&apos;' value='32'/>
 			<EnumValue name='&apos;StepsType_Lights_Cabinet&apos;' value='33'/>
+			<EnumValue name='&apos;StepsType_Kickbox_Human&apos;' value='34'/>
+			<EnumValue name='&apos;StepsType_Kickbox_Quadarm&apos;' value='35'/>
+			<EnumValue name='&apos;StepsType_Kickbox_Insect&apos;' value='36'/>
+			<EnumValue name='&apos;StepsType_Kickbox_Arachnid&apos;' value='37'/>
 		</Enum>
 		<Enum name='StyleType'>
 			<EnumValue name='&apos;StyleType_OnePlayerOneSide&apos;' value='0'/>
@@ -2858,6 +2929,6 @@
 		<Constant name='right' value='&apos;HorizAlign_Right&apos;'/>
 		<Constant name='top' value='&apos;VertAlign_Top&apos;'/>
 	</Constants>
-	<Version>StepMania v5.0 beta 3</Version>
-	<Date>2014-09-15</Date>
+	<Version>StepMania5.1-git-d03ec2658f</Version>
+	<Date>2020-05-11</Date>
 </Lua>

From 653e8ff6fe4a077bb01d451daaa279e37f8f1a0c Mon Sep 17 00:00:00 2001
From: din <dinsfire64@gmail.com>
Date: Thu, 14 May 2020 16:19:23 -0500
Subject: [PATCH 23/65] Small memory fixes.

---
 src/RageSurface_Load_PNG.cpp                | 6 +++++-
 src/arch/InputHandler/LinuxInputManager.cpp | 2 ++
 src/archutils/Unix/SignalHandler.cpp        | 9 +++++----
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/RageSurface_Load_PNG.cpp b/src/RageSurface_Load_PNG.cpp
index 17d0de9390..4549eccfb8 100644
--- a/src/RageSurface_Load_PNG.cpp
+++ b/src/RageSurface_Load_PNG.cpp
@@ -123,7 +123,6 @@ static RageSurface *RageSurface_Load_PNG( RageFile *f, const char *fn, char erro
 		CHECKPOINT_M("Header only png about to be processed.");
 		img = CreateSurfaceFrom( width, height, 32, 0, 0, 0, 0, nullptr, width*4 );
 		png_destroy_read_struct( &png, &info_ptr, nullptr );
-
 		return img;
 	}
 
@@ -255,6 +254,11 @@ static RageSurface *RageSurface_Load_PNG( RageFile *f, const char *fn, char erro
 	png_read_end( png, info_ptr );
 	png_destroy_read_struct( &png, &info_ptr, nullptr );
 
+	if(row_pointers != nullptr)
+	{
+		delete[] row_pointers;
+	}
+
 	return img;
 }
 
diff --git a/src/arch/InputHandler/LinuxInputManager.cpp b/src/arch/InputHandler/LinuxInputManager.cpp
index 2981eccd53..3961687100 100644
--- a/src/arch/InputHandler/LinuxInputManager.cpp
+++ b/src/arch/InputHandler/LinuxInputManager.cpp
@@ -80,6 +80,8 @@ LinuxInputManager::LinuxInputManager()
 	// Sort devices for more consistent numbering.
 	std::sort(m_vsPendingEventDevices.begin(), m_vsPendingEventDevices.end(), cmpDevices);
 	std::sort(m_vsPendingJoystickDevices.begin(), m_vsPendingJoystickDevices.end(), cmpDevices);
+
+	closedir(sysClassInput);
 }
 
 void LinuxInputManager::InitDriver(InputHandler_Linux_Event* driver)
diff --git a/src/archutils/Unix/SignalHandler.cpp b/src/archutils/Unix/SignalHandler.cpp
index e049cbb849..5ec0ee8ea6 100644
--- a/src/archutils/Unix/SignalHandler.cpp
+++ b/src/archutils/Unix/SignalHandler.cpp
@@ -3,6 +3,7 @@
 #include "RageLog.h"
 #include "SignalHandler.h"
 #include "GetSysInfo.h"
+#include <memory>
 
 #if defined(HAVE_LIBPTHREAD)
 #include "archutils/Common/PthreadHelpers.h"
@@ -31,7 +32,7 @@ static int find_stack_direction2( char *p ) NOINLINE;
 static int find_stack_direction() NOINLINE;
 
 static vector<SignalHandler::handler> handlers;
-SaveSignals *saved_sigs;
+unique_ptr<SaveSignals> saved_sigs;
 
 static int signals[] =
 {
@@ -143,10 +144,10 @@ static void *CreateStack( int size )
 /* Hook up events to fatal signals, so we can clean up if we're killed. */
 void SignalHandler::OnClose( handler h )
 {
-	if( saved_sigs == nullptr )
+	//if the unique_ptr has not been set, then enter.
+	if( !saved_sigs )
 	{
-		saved_sigs = new SaveSignals;
-
+		saved_sigs.reset(new SaveSignals());
 		bool bUseAltSigStack = true;
 
 #if defined(LINUX)

From a10f16cb3c618fd040a4e010ad5b914a0d900363 Mon Sep 17 00:00:00 2001
From: Marshall Polaris <marshall@pol.rs>
Date: Fri, 15 May 2020 21:24:16 -0700
Subject: [PATCH 24/65] Log errors while reading joystick input

---
 src/arch/InputHandler/InputHandler_Linux_Joystick.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/arch/InputHandler/InputHandler_Linux_Joystick.cpp b/src/arch/InputHandler/InputHandler_Linux_Joystick.cpp
index d61c2082eb..38728d11dc 100644
--- a/src/arch/InputHandler/InputHandler_Linux_Joystick.cpp
+++ b/src/arch/InputHandler/InputHandler_Linux_Joystick.cpp
@@ -140,6 +140,15 @@ void InputHandler_Linux_Joystick::InputThread()
 
 			js_event event;
 			int ret = read(fds[i], &event, sizeof(event));
+
+			if(ret == -1)
+			{
+				LOG->Warn("Error reading from joystick %i: %s; disabled", i, strerror(errno));
+				close(fds[i]);
+				fds[i] = -1;
+				continue;
+			}
+
 			if(ret != sizeof(event))
 			{
 				LOG->Warn("Unexpected packet (size %i != %i) from joystick %i; disabled", ret, (int)sizeof(event), i);

From 12e983ba51e9edb3ae7e2cf1c917f5710c3aad39 Mon Sep 17 00:00:00 2001
From: RhythmLunatic <kirbyrulez@att.net>
Date: Tue, 26 May 2020 22:36:53 -0500
Subject: [PATCH 25/65] add GetCurrentSections

---
 src/MusicWheel.cpp | 18 ++++++++++++++++++
 src/MusicWheel.h   |  1 +
 2 files changed, 19 insertions(+)

diff --git a/src/MusicWheel.cpp b/src/MusicWheel.cpp
index 5a94cf75fb..ce7a8f3324 100644
--- a/src/MusicWheel.cpp
+++ b/src/MusicWheel.cpp
@@ -1468,6 +1468,16 @@ void MusicWheel::SetOpenSection( RString group )
 	RebuildWheelItems();
 }
 
+void MusicWheel::GetCurrentSections(vector<RString> &sections)
+{
+	vector<MusicWheelItemData *> &wiWheelItems = getWheelItemsData(GAMESTATE->m_SortOrder);
+	for( unsigned i = 0; i < wiWheelItems.size(); i++ )
+	{
+		if ( wiWheelItems[i]->m_Type == WheelItemDataType_Section && !wiWheelItems[i]->m_sText.empty())
+			sections.push_back(wiWheelItems[i]->m_sText);
+	}
+}
+
 // sm-ssc additions: jump to group
 RString MusicWheel::JumpToNextGroup()
 {
@@ -1693,6 +1703,13 @@ public:
 		return 1;
 	}
 	DEFINE_METHOD(GetSelectedSection, GetSelectedSection());
+	static int GetCurrentSections( T* p, lua_State *L )
+	{
+		vector<RString> v;
+		p->GetCurrentSections(v);
+		LuaHelpers::CreateTableFromArray<RString>( v, L );
+		return 1;
+	}
 	static int IsRouletting( T* p, lua_State *L ){ lua_pushboolean( L, p->IsRouletting() ); return 1; }
 	static int SelectSong( T* p, lua_State *L )
 	{
@@ -1733,6 +1750,7 @@ public:
 		ADD_METHOD( SelectSong );
 		ADD_METHOD( SelectCourse );
 		ADD_METHOD( Move );
+		ADD_METHOD( GetCurrentSections );
 	}
 };
 
diff --git a/src/MusicWheel.h b/src/MusicWheel.h
index e894820066..232e8bd9da 100644
--- a/src/MusicWheel.h
+++ b/src/MusicWheel.h
@@ -52,6 +52,7 @@ public:
 
 	virtual void ReloadSongList();
 
+	void GetCurrentSections(vector<RString> &sections);
 	// Lua
 	void PushSelf( lua_State *L );
 

From 6bcae89aaf1adaa2b241e10c522a657ee4ce0d64 Mon Sep 17 00:00:00 2001
From: RhythmLunatic <kirbyrulez@att.net>
Date: Tue, 26 May 2020 22:45:50 -0500
Subject: [PATCH 26/65] Update documentation

---
 Docs/Luadoc/Lua.xml              | 1 +
 Docs/Luadoc/LuaDocumentation.xml | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/Docs/Luadoc/Lua.xml b/Docs/Luadoc/Lua.xml
index 0cc660c3ce..bec2e01f46 100644
--- a/Docs/Luadoc/Lua.xml
+++ b/Docs/Luadoc/Lua.xml
@@ -1065,6 +1065,7 @@
 			<Function name='Move'/>
 			<Function name='SelectCourse'/>
 			<Function name='SelectSong'/>
+			<Function name='GetCurrentSections' />
 		</Class>
 		<Class name='NCSplineHandler'>
 			<Function name='get_spline'/>
diff --git a/Docs/Luadoc/LuaDocumentation.xml b/Docs/Luadoc/LuaDocumentation.xml
index d4583be1dc..fa3d5be716 100644
--- a/Docs/Luadoc/LuaDocumentation.xml
+++ b/Docs/Luadoc/LuaDocumentation.xml
@@ -3235,6 +3235,9 @@ save yourself some time, copy this for undocumented things:
 	<Function name='SelectCourse' return='bool' arguments='Course cCourse'>
 		Selects a course. Returns <code>false</code> on failure.
 	</Function>
+	<Function name='GetCurrentSections' return='{string}' arguments=''>
+		Returns the current sections in the MusicWheel, for use with a custom group select that supports sorting.
+	</Function>
 </Class>
 <Class name='NoteSkinManager'>
 	<Function name='GetMetric' return='string' arguments='string sElement, string sValue'>

From 88f7d346326fb3a009a5e75af0e2119a5950db5e Mon Sep 17 00:00:00 2001
From: RhythmLunatic <kirbyrulez@att.net>
Date: Tue, 26 May 2020 23:15:16 -0500
Subject: [PATCH 27/65] Slightly more clear documentation

---
 Docs/Luadoc/LuaDocumentation.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Docs/Luadoc/LuaDocumentation.xml b/Docs/Luadoc/LuaDocumentation.xml
index fa3d5be716..765ecc3aaa 100644
--- a/Docs/Luadoc/LuaDocumentation.xml
+++ b/Docs/Luadoc/LuaDocumentation.xml
@@ -3236,7 +3236,7 @@ save yourself some time, copy this for undocumented things:
 		Selects a course. Returns <code>false</code> on failure.
 	</Function>
 	<Function name='GetCurrentSections' return='{string}' arguments=''>
-		Returns the current sections in the MusicWheel, for use with a custom group select that supports sorting.
+		Returns a string array of the currently displayed sections in the MusicWheel.
 	</Function>
 </Class>
 <Class name='NoteSkinManager'>

From 9ab72f4fb5bf678db6ad3eb8b99130363dd58990 Mon Sep 17 00:00:00 2001
From: Richard Loxley <4620670+richardloxley@users.noreply.github.com>
Date: Thu, 4 Jun 2020 16:40:28 +0100
Subject: [PATCH 28/65] Fix issue 2005: incorrect announcer sound files are
 played on the evaluation screen if the current theme doesn't have exactly 7
 grade tiers. This change maps the new grade tiers evenly to the 7 old grade
 tiers to trigger the correct sound files. It also extends that mapping to the
 grade tiers used for playing cheering for the top few tiers.

---
 src/Grade.cpp            | 12 +++++++++++-
 src/Grade.h              |  1 +
 src/ScreenEvaluation.cpp |  2 +-
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/Grade.cpp b/src/Grade.cpp
index bcf34cc01a..5b04df78a0 100644
--- a/src/Grade.cpp
+++ b/src/Grade.cpp
@@ -33,7 +33,7 @@ RString GradeToLocalizedString( Grade g )
 RString GradeToOldString( Grade g )
 {
 	// string is meant to be human readable
-	switch( g )
+	switch( GradeToOldGrade(g) )
 	{
 	case Grade_Tier01:	return "AAAA";
 	case Grade_Tier02:	return "AAA";
@@ -48,6 +48,16 @@ RString GradeToOldString( Grade g )
 	}
 };
 
+Grade GradeToOldGrade( Grade g )
+{
+	// There used to be 7 grades (plus fail) but grades can now be defined by themes.
+	// So we need to re-scale the grade bands based on how many actual grades the theme defines.
+	if( g < NUM_GRADE_TIERS_USED )
+		g = (Grade)round((double)g * Grade_Tier07 / (NUM_GRADE_TIERS_USED - 1));
+
+	return g;
+}
+
 Grade StringToGrade( const RString &sGrade )
 {
 	RString s = sGrade;
diff --git a/src/Grade.h b/src/Grade.h
index e1703a8dee..aa3c740a9e 100644
--- a/src/Grade.h
+++ b/src/Grade.h
@@ -67,6 +67,7 @@ static inline RString GradeToString( Grade g )
  * @param g the current Grade.
  * @return the old styled grade string. */
 RString GradeToOldString( Grade g );
+Grade GradeToOldGrade( Grade g );
 RString GradeToLocalizedString( Grade g );
 /**
  * @brief Convert the given RString into a proper Grade.
diff --git a/src/ScreenEvaluation.cpp b/src/ScreenEvaluation.cpp
index 79ab877702..d77e57c745 100644
--- a/src/ScreenEvaluation.cpp
+++ b/src/ScreenEvaluation.cpp
@@ -709,7 +709,7 @@ void ScreenEvaluation::Init()
 		}
 	}
 
-	switch( best_grade )
+	switch( GradeToOldGrade(best_grade) )
 	{
 		case Grade_Tier01:
 		case Grade_Tier02:

From ff75af1f20a7821e40dad3994e5845c5b3bd2d87 Mon Sep 17 00:00:00 2001
From: Jonathan Albert <47063257+jalbert-dev@users.noreply.github.com>
Date: Thu, 16 May 2019 13:46:03 -0400
Subject: [PATCH 29/65] Fix song selection in trail generation (for
 nonstop/oni)

---
 src/Course.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Course.cpp b/src/Course.cpp
index 90bb15faa4..1a7c0eda1d 100644
--- a/src/Course.cpp
+++ b/src/Course.cpp
@@ -454,9 +454,9 @@ bool Course::GetTrailUnsorted( StepsType st, CourseDifficulty cd, Trail &trail )
 	}
 	else
 	{
-		vector<SongAndSteps> vSongAndSteps;
-		for (std::vector<CourseEntry>::const_iterator e = entries.begin(); e != entries.end(); ++e)
+		for (auto e = entries.begin(); e != entries.end(); ++e)
 		{
+			vector<SongAndSteps> vSongAndSteps;
 			SongAndSteps resolved;	// fill this in
 			SongCriteria soc = e->songCriteria;
 

From 3bb1045ce13eebbd13570109126528c53a1ffc21 Mon Sep 17 00:00:00 2001
From: Jonathan Albert <47063257+jalbert-dev@users.noreply.github.com>
Date: Thu, 16 May 2019 21:12:32 -0400
Subject: [PATCH 30/65] Fix crash when getting matching steps in endless
 courses

---
 src/StepsUtil.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/StepsUtil.cpp b/src/StepsUtil.cpp
index 6df151b2c5..7f82eb9112 100644
--- a/src/StepsUtil.cpp
+++ b/src/StepsUtil.cpp
@@ -74,7 +74,7 @@ void StepsUtil::GetAllMatchingEndless( Song *pSong, const StepsCriteria &stc, ve
 		successful = true;
 	}
 
-	if( !successful )
+	if( !successful && vSteps.size() > 0 )
 	{
 		Difficulty difficulty = ( *( vSteps.begin() ) )->GetDifficulty();
 		Difficulty previousDifficulty = difficulty;

From 1e6b0d7f35e8f4613d368a17ff0e0f2691c9e7b3 Mon Sep 17 00:00:00 2001
From: Jonathan Albert <47063257+jalbert-dev@users.noreply.github.com>
Date: Thu, 23 May 2019 23:30:26 -0400
Subject: [PATCH 31/65] Fix trail generation in endless mode courses

---
 src/Course.cpp | 108 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 71 insertions(+), 37 deletions(-)

diff --git a/src/Course.cpp b/src/Course.cpp
index 1a7c0eda1d..c16ae4c378 100644
--- a/src/Course.cpp
+++ b/src/Course.cpp
@@ -651,15 +651,12 @@ bool Course::GetTrailUnsorted( StepsType st, CourseDifficulty cd, Trail &trail )
 void Course::GetTrailUnsortedEndless( const vector<CourseEntry> &entries, Trail &trail, StepsType &st, 
 	CourseDifficulty &cd, RandomGen &rnd, bool &bCourseDifficultyIsSignificant ) const
 {
-	vector<Song*> vpAllPossibleSongs;
-	vector<SongAndSteps> vSongAndSteps;
-	vector<Song*> vpSongs;
 	typedef vector<Steps*> StepsVector;
-	map<Song*, StepsVector> mapSongToSteps;
-	int songIndex = 0;
-	bool vpSongsSorted = false;
-	// Resolve each entry to a Song and Steps.
-	for (std::vector<CourseEntry>::const_iterator e = entries.begin(); e != entries.end(); ++e)
+
+	std::set<Song*> alreadySelected;
+	Song* lastSongSelected;
+	vector<SongAndSteps> vSongAndSteps;
+	for (auto e = entries.begin(); e != entries.end(); ++e)
 	{
 
 		SongAndSteps resolved;	// fill this in
@@ -684,8 +681,11 @@ void Course::GetTrailUnsortedEndless( const vector<CourseEntry> &entries, Trail
 		const bool bSameSongCriteria = e != entries.begin() && ( e - 1 )->songCriteria == soc;
 		const bool bSameStepsCriteria = e != entries.begin() && ( e - 1 )->stepsCriteria == stc;
 
+		// If we're doing the same wildcard search as last entry,
+		// we can just reuse the vSongAndSteps vector.
 		if( pSong )
 		{
+			vSongAndSteps.clear();
 			StepsUtil::GetAllMatchingEndless( pSong, stc, vSongAndSteps );
 		}
 		else if( vSongAndSteps.empty() || !( bSameSongCriteria && bSameStepsCriteria ) )
@@ -698,40 +698,74 @@ void Course::GetTrailUnsortedEndless( const vector<CourseEntry> &entries, Trail
 		if( vSongAndSteps.empty() )
 			continue;
 
-		if( !vpSongsSorted && !vSongAndSteps.empty() ) {
-			vector<Song*> vpSongs;
-			typedef vector<Steps*> StepsVector;
-			map<Song*,StepsVector> mapSongToSteps;
-			for (SongAndSteps const &sas : vSongAndSteps)
+		// if we're doing a RANDOM wildcard search, try to avoid repetition
+		if (vSongAndSteps.size() > 1 && e->songSort == SongSort::SongSort_Randomize)
+		{
+			// Make a backup of the steplist so we can revert if we overfilter
+			std::vector<SongAndSteps> revertList = vSongAndSteps;
+			// Filter candidate list via blacklist
+			vSongAndSteps.erase(std::remove_if(
+				vSongAndSteps.begin(),
+				vSongAndSteps.end(),
+				[&](const SongAndSteps& ss) {
+					return std::find(alreadySelected.begin(), alreadySelected.end(), ss.pSong) != alreadySelected.end();
+				}),
+				vSongAndSteps.end());
+			// If every candidate is in the blacklist, pick random song that wasn't played last
+			// (Repeat songs may still occur if song after this is fixed; this algorithm doesn't look ahead)
+			if (vSongAndSteps.empty())
 			{
-				StepsVector &v = mapSongToSteps[sas.pSong];
-				v.push_back( sas.pSteps );
-				if( v.size() == 1 )
-					vpSongs.push_back( sas.pSong );
+				vSongAndSteps = revertList;
+				vSongAndSteps.erase(std::remove_if(
+					vSongAndSteps.begin(),
+					vSongAndSteps.end(),
+					[&](const SongAndSteps& ss) {
+						return ss.pSong == lastSongSelected;
+					}),
+					vSongAndSteps.end());
+
+				// If the song that was played last was the only candidate, forget it
+				if (vSongAndSteps.empty())
+				{
+					vSongAndSteps = revertList;
+				}
 			}
-			vpSongsSorted = true;
-			CourseSortSongs( e->songSort, vpSongs, rnd );
-			songIndex = 0;
 		}
 
-		ASSERT( e->iChooseIndex >= 0 );
-		if( e->iChooseIndex < static_cast<int>(vSongAndSteps.size()) )
+		std::vector<Song*> vpSongs;
+		std::map<Song*, StepsVector> songStepMap;
+		// Build list of songs for sorting, and mapping of songs to steps simultaneously
+		for (auto& ss : vSongAndSteps)
 		{
-			if( songIndex >= int(vpSongs.size()) ) {
-				songIndex = 0;
+			StepsVector& stepsForSong = songStepMap[ss.pSong];
+			// If we haven't noted this song yet, add it to the song list
+			if (stepsForSong.size() == 0)
+			{
+				vpSongs.push_back(ss.pSong);
 			}
-			resolved.pSong = vpSongs[ songIndex ];
-			const vector<Steps*> &mappedSongs = mapSongToSteps[ resolved.pSong ];
-			songIndex++;
-			resolved.pSteps = mappedSongs[ RandomInt( mappedSongs.size() ) ];
+
+			stepsForSong.push_back(ss.pSteps);
 		}
-		else
-		{
+
+		ASSERT(e->iChooseIndex >= 0);
+		// If we're trying to pick BEST100 when only 99 songs exist,
+		// we have a problem, so bail out
+		if (e->iChooseIndex >= vpSongs.size()) {
 			continue;
 		}
 
-		/* If we're not COURSE_DIFFICULTY_REGULAR, then we should be choosing steps that are 
-		 * either easier or harder than the base difficulty.  If no such steps exist, then 
+
+		// Otherwise, pick random steps corresponding to the selected song
+		CourseSortSongs(e->songSort, vpSongs, rnd);
+		resolved.pSong = vpSongs[e->iChooseIndex];
+		const vector<Steps*>& songSteps = songStepMap[resolved.pSong];
+		resolved.pSteps = songSteps[random_up_to(rnd, songSteps.size())];
+
+		lastSongSelected = resolved.pSong;
+		alreadySelected.emplace(resolved.pSong);
+
+		/* If we're not COURSE_DIFFICULTY_REGULAR, then we should be choosing steps that are
+		 * either easier or harder than the base difficulty.  If no such steps exist, then
 		 * just use the one we already have. */
 		Difficulty dc = resolved.pSteps->GetDifficulty();
 		int iLowMeter = e->stepsCriteria.m_iLowMeter;
@@ -825,11 +859,11 @@ void Course::GetTrailUnsortedEndless( const vector<CourseEntry> &entries, Trail
 		}
 
 		trail.m_vEntries.push_back( te );
-		if( trail.m_vEntries.size() > 0 && te.dc != cd )
-		{
-			trail.m_vEntries.reserve( trail.m_vEntries.size() - 1 );
-			trail.m_vEntries.resize( trail.m_vEntries.size() - 1 );
-		}
+		//if( trail.m_vEntries.size() > 0 && te.dc != cd )
+		//{
+		//	trail.m_vEntries.reserve( trail.m_vEntries.size() - 1 );
+		//	trail.m_vEntries.resize( trail.m_vEntries.size() - 1 );
+		//}
 		// LOG->Trace( "Chose: %s, %d", te.pSong->GetSongDir().c_str(), te.pSteps->GetMeter() );
 
 		if( IsAnEdit() && MAX_SONGS_IN_EDIT_COURSE > 0 &&

From f49229809d64fa12f99be1316836b4548bf1816b Mon Sep 17 00:00:00 2001
From: Jonathan Albert <47063257+jalbert-dev@users.noreply.github.com>
Date: Fri, 24 May 2019 00:15:17 -0400
Subject: [PATCH 32/65] Minor fixes

---
 src/Course.cpp | 28 +++++++---------------------
 1 file changed, 7 insertions(+), 21 deletions(-)

diff --git a/src/Course.cpp b/src/Course.cpp
index c16ae4c378..0ef38c2a1b 100644
--- a/src/Course.cpp
+++ b/src/Course.cpp
@@ -454,9 +454,9 @@ bool Course::GetTrailUnsorted( StepsType st, CourseDifficulty cd, Trail &trail )
 	}
 	else
 	{
+		vector<SongAndSteps> vSongAndSteps;
 		for (auto e = entries.begin(); e != entries.end(); ++e)
 		{
-			vector<SongAndSteps> vSongAndSteps;
 			SongAndSteps resolved;	// fill this in
 			SongCriteria soc = e->songCriteria;
 
@@ -480,6 +480,7 @@ bool Course::GetTrailUnsorted( StepsType st, CourseDifficulty cd, Trail &trail )
 
 			if( pSong )
 			{
+				vSongAndSteps.clear();
 				StepsUtil::GetAllMatching( pSong, stc, vSongAndSteps );
 			}
 			else if( vSongAndSteps.empty() || !( bSameSongCriteria && bSameStepsCriteria ) )
@@ -704,27 +705,17 @@ void Course::GetTrailUnsortedEndless( const vector<CourseEntry> &entries, Trail
 			// Make a backup of the steplist so we can revert if we overfilter
 			std::vector<SongAndSteps> revertList = vSongAndSteps;
 			// Filter candidate list via blacklist
-			vSongAndSteps.erase(std::remove_if(
-				vSongAndSteps.begin(),
-				vSongAndSteps.end(),
-				[&](const SongAndSteps& ss) {
-					return std::find(alreadySelected.begin(), alreadySelected.end(), ss.pSong) != alreadySelected.end();
-				}),
-				vSongAndSteps.end());
+			RemoveIf(vSongAndSteps, [&](const SongAndSteps& ss) {
+				return std::find(alreadySelected.begin(), alreadySelected.end(), ss.pSong) != alreadySelected.end();
+			});
 			// If every candidate is in the blacklist, pick random song that wasn't played last
 			// (Repeat songs may still occur if song after this is fixed; this algorithm doesn't look ahead)
 			if (vSongAndSteps.empty())
 			{
 				vSongAndSteps = revertList;
-				vSongAndSteps.erase(std::remove_if(
-					vSongAndSteps.begin(),
-					vSongAndSteps.end(),
-					[&](const SongAndSteps& ss) {
-						return ss.pSong == lastSongSelected;
-					}),
-					vSongAndSteps.end());
+				RemoveIf(vSongAndSteps, SongIsEqual(lastSongSelected));
 
-				// If the song that was played last was the only candidate, forget it
+				// If the song that was played last was the only candidate, give up pick randomly
 				if (vSongAndSteps.empty())
 				{
 					vSongAndSteps = revertList;
@@ -859,11 +850,6 @@ void Course::GetTrailUnsortedEndless( const vector<CourseEntry> &entries, Trail
 		}
 
 		trail.m_vEntries.push_back( te );
-		//if( trail.m_vEntries.size() > 0 && te.dc != cd )
-		//{
-		//	trail.m_vEntries.reserve( trail.m_vEntries.size() - 1 );
-		//	trail.m_vEntries.resize( trail.m_vEntries.size() - 1 );
-		//}
 		// LOG->Trace( "Chose: %s, %d", te.pSong->GetSongDir().c_str(), te.pSteps->GetMeter() );
 
 		if( IsAnEdit() && MAX_SONGS_IN_EDIT_COURSE > 0 &&

From 3ba2b8ba541138a4301ca35fd248b4fa45ed2779 Mon Sep 17 00:00:00 2001
From: quietly turning <quietly.turning@gmail.com>
Date: Sun, 7 Jun 2020 20:09:37 -0400
Subject: [PATCH 33/65] fix Course.cpp for 5_1-new

random_up_to() was written for SM5.2 and RageUtil's RandomInt() seems
a suitable replacement for 5_1-new.
---
 src/Course.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Course.cpp b/src/Course.cpp
index 0ef38c2a1b..93ed2950f7 100644
--- a/src/Course.cpp
+++ b/src/Course.cpp
@@ -750,7 +750,7 @@ void Course::GetTrailUnsortedEndless( const vector<CourseEntry> &entries, Trail
 		CourseSortSongs(e->songSort, vpSongs, rnd);
 		resolved.pSong = vpSongs[e->iChooseIndex];
 		const vector<Steps*>& songSteps = songStepMap[resolved.pSong];
-		resolved.pSteps = songSteps[random_up_to(rnd, songSteps.size())];
+		resolved.pSteps = songSteps[RandomInt(songSteps.size())];
 
 		lastSongSelected = resolved.pSong;
 		alreadySelected.emplace(resolved.pSong);

From 0befd8bf104d36f30f7ad07ad0b48c5253b3040b Mon Sep 17 00:00:00 2001
From: RhythmLunatic <kirbyrulez@att.net>
Date: Fri, 12 Jun 2020 15:19:26 -0500
Subject: [PATCH 34/65] Write description tag to cache

---
 src/CourseWriterCRS.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/CourseWriterCRS.cpp b/src/CourseWriterCRS.cpp
index 8a52095667..c479f45181 100644
--- a/src/CourseWriterCRS.cpp
+++ b/src/CourseWriterCRS.cpp
@@ -48,6 +48,8 @@ bool CourseWriterCRS::Write( const Course &course, RageFileBasic &f, bool bSavin
 		f.PutLine( ssprintf("#COURSETRANSLIT:%s;", course.m_sMainTitleTranslit.c_str()) );
 	if( course.m_sScripter != "" )
 		f.PutLine( ssprintf("#SCRIPTER:%s;", course.m_sScripter.c_str()) );
+	if (course.m_sDescription != "")
+	    f.PutLine( ssprintf("#DESCRIPTION:%s;", course.m_sDescription.c_str()) );
 	if( course.m_bRepeat )
 		f.PutLine( "#REPEAT:YES;" );
 	if( course.m_iLives != -1 )

From b300bb516d28283437ad8b6c86c65bd1444ab388 Mon Sep 17 00:00:00 2001
From: RhythmLunatic <kirbyrulez@att.net>
Date: Fri, 12 Jun 2020 15:21:08 -0500
Subject: [PATCH 35/65] Format it like the other lines

---
 src/CourseWriterCRS.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/CourseWriterCRS.cpp b/src/CourseWriterCRS.cpp
index c479f45181..684a26e215 100644
--- a/src/CourseWriterCRS.cpp
+++ b/src/CourseWriterCRS.cpp
@@ -48,7 +48,7 @@ bool CourseWriterCRS::Write( const Course &course, RageFileBasic &f, bool bSavin
 		f.PutLine( ssprintf("#COURSETRANSLIT:%s;", course.m_sMainTitleTranslit.c_str()) );
 	if( course.m_sScripter != "" )
 		f.PutLine( ssprintf("#SCRIPTER:%s;", course.m_sScripter.c_str()) );
-	if (course.m_sDescription != "")
+	if ( course.m_sDescription != "" )
 	    f.PutLine( ssprintf("#DESCRIPTION:%s;", course.m_sDescription.c_str()) );
 	if( course.m_bRepeat )
 		f.PutLine( "#REPEAT:YES;" );

From 10e3a2f2e827307da455618c39a473c142a2fd73 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Sat, 13 Jun 2020 15:40:50 +0200
Subject: [PATCH 36/65] Don't cast doubles to enums

C:\Repos\StepMania\src\Grade.cpp(56): error C2440: 'type cast': cannot convert from 'double' to 'Grade' [C:\Repos\StepMania\Build\src\StepMania.vcxproj]
  C:\Repos\StepMania\src\Grade.cpp(56): note: Conversions between enumeration and floating point values are no longer allowed
---
 src/Grade.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Grade.cpp b/src/Grade.cpp
index 5b04df78a0..82a1de93be 100644
--- a/src/Grade.cpp
+++ b/src/Grade.cpp
@@ -53,7 +53,7 @@ Grade GradeToOldGrade( Grade g )
 	// There used to be 7 grades (plus fail) but grades can now be defined by themes.
 	// So we need to re-scale the grade bands based on how many actual grades the theme defines.
 	if( g < NUM_GRADE_TIERS_USED )
-		g = (Grade)round((double)g * Grade_Tier07 / (NUM_GRADE_TIERS_USED - 1));
+		g = (Grade)std::lround((double)g * Grade_Tier07 / (NUM_GRADE_TIERS_USED - 1));
 
 	return g;
 }

From ecdad57d7050773dd5ecd678af955e129e2c09db Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Sat, 13 Jun 2020 16:18:45 +0200
Subject: [PATCH 37/65] Add GitHub Actions CI

---
 .github/workflows/ci.yml | 97 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 .github/workflows/ci.yml

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000000..c753c82a09
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,97 @@
+on: [push, pull_request]
+
+name: Continuous integration
+
+jobs:
+  ubuntu-build-bundled:
+    name: "Ubuntu: Build with bundled libraries"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        run: sudo apt-get update && sudo apt-get install -y
+          libasound2-dev
+          libgl-dev
+          libglew-dev
+          libgtk2.0-dev
+          libjack-dev
+          libmad0-dev
+          libpulse-dev
+          libva-dev
+          libvorbis-dev
+          libxinerama-dev
+          libx11-dev
+          libxrandr-dev
+          libxtst-dev
+          nasm
+      - name: Configure
+        run: cmake -B build
+      - name: Build
+        run: cmake --build build
+
+  ubuntu-build-system:
+    name: "Ubuntu: Build with system libraries"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        run: sudo apt-get update && sudo apt-get install -y
+          ffmpeg
+          libasound2-dev
+          libgl-dev
+          libglew-dev
+          libgtk2.0-dev
+          libjack-dev
+          libjsoncpp-dev
+          libmad0-dev
+          libpulse-dev
+          libtomcrypt-dev
+          libtommath-dev
+          libva-dev
+          libvorbis-dev
+          libxinerama-dev
+          libx11-dev
+          libxrandr-dev
+          libxtst-dev
+          ninja-build
+      - name: Configure
+        # TODO: jsoncpp: https://github.com/stepmania/stepmania/issues/1883
+        # TODO: png: https://github.com/stepmania/stepmania/issues/1881
+        # TODO: tomcrypt: https://github.com/stepmania/stepmania/issues/1885
+        run: cmake -G Ninja -B build
+          -DWITH_SYSTEM_FFMPEG=ON
+          -DWITH_SYSTEM_GLEW=ON
+          -DWITH_SYSTEM_JPEG=ON
+          -DWITH_SYSTEM_JSONCPP=OFF
+          -DWITH_SYSTEM_MAD=ON
+          -DWITH_SYSTEM_OGG=ON
+          -DWITH_SYSTEM_PCRE=ON
+          -DWITH_SYSTEM_PNG=OFF
+          -DWITH_SYSTEM_TOMCRYPT=OFF
+          -DWITH_SYSTEM_TOMMATH=ON
+          -DWITH_SYSTEM_ZLIB=ON
+      - name: Build
+        run: cmake --build build
+
+  macos-build-bundled:
+    name: "macOS: Build with bundled libraries"
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        run: brew install
+          nasm
+      - name: Configure
+        run: cmake -B build
+      - name: Build
+        run: cmake --build build
+
+  windows-build-bundled:
+    name: "Windows: Build with bundled libraries"
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Configure
+        run: cmake -B build
+      - name: Build
+        run: cmake --build build

From b24abc6f1f0d724e5a82cb20392ac27d47ae8bfc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Sat, 13 Jun 2020 20:00:58 +0200
Subject: [PATCH 38/65] Add GitHub Actions badge

---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index a6a00f4149..fa9073e440 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,7 @@ StepMania is an advanced cross-platform rhythm game for home and arcade use.
 
 Advanced cross-platform rhythm game for home and arcade use.
 
+[![Continuous integration](https://github.com/stepmania/stepmania/workflows/Continuous%20integration/badge.svg?branch=master)](https://github.com/stepmania/stepmania/actions?query=workflow%3A%22Continuous+integration%22+branch%3Amaster)
 [![Build Status](https://travis-ci.org/stepmania/stepmania.svg?branch=master)](https://travis-ci.org/stepmania/stepmania)
 [![Build status](https://ci.appveyor.com/api/projects/status/uvoplsnyoats81r2?svg=true)](https://ci.appveyor.com/project/Nickito12/stepmania)
 

From dc25295879a4222794ae9a27971710cc97ccfee6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <m.kroening@hotmail.de>
Date: Mon, 9 Sep 2019 11:09:52 +0200
Subject: [PATCH 39/65] Catch stoi invalid_argument in BGCHANGES

---
 src/NotesLoaderSM.cpp | 41 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 36 insertions(+), 5 deletions(-)

diff --git a/src/NotesLoaderSM.cpp b/src/NotesLoaderSM.cpp
index 8f2c219912..fa2a6c0279 100644
--- a/src/NotesLoaderSM.cpp
+++ b/src/NotesLoaderSM.cpp
@@ -976,9 +976,18 @@ bool SMLoader::LoadFromBGChangesVector( BackgroundChange &change, std::vector<RS
 		// Backward compatibility:
 		if( change.m_def.m_sEffect.empty() )
 		{
-			bool bLoop = std::stoi( aBGChangeValues[5] ) != 0;
-			if( !bLoop )
+			try
+			{
+				if( std::stoi( aBGChangeValues[5] ) != 0 )
+				{
+					change.m_def.m_sEffect = SBE_StretchNoLoop;
+				}
+			}
+			catch ( const std::invalid_argument & )
+			{
+				// Failed conversions mean it's not 0 as well
 				change.m_def.m_sEffect = SBE_StretchNoLoop;
+			}
 		}
 		// fall through
 	case 5:
@@ -986,16 +995,38 @@ bool SMLoader::LoadFromBGChangesVector( BackgroundChange &change, std::vector<RS
 		// Backward compatibility:
 		if( change.m_def.m_sEffect.empty() )
 		{
-			bool bRewindMovie = std::stoi( aBGChangeValues[4] ) != 0;
-			if( bRewindMovie )
+			try
+			{
+				if( std::stoi( aBGChangeValues[4] ) != 0 )
+				{
+					change.m_def.m_sEffect = SBE_StretchRewind;
+				}
+			}
+			catch ( const std::invalid_argument & )
+			{
+				// Failed conversions mean it's not 0 as well
 				change.m_def.m_sEffect = SBE_StretchRewind;
+			}
 		}
 		// fall through
 	case 4:
 		// param 9 overrides this.
 		// Backward compatibility:
 		if( change.m_sTransition.empty() )
-			change.m_sTransition = (std::stoi( aBGChangeValues[3] ) != 0) ? "CrossFade" : "";
+		{
+			try
+			{
+				if( std::stoi( aBGChangeValues[3] ) != 0 )
+				{
+					change.m_sTransition = SBT_CrossFade;
+				}
+			}
+			catch ( const std::invalid_argument & )
+			{
+				// Failed conversions mean it's not 0 as well
+				change.m_sTransition = SBT_CrossFade;
+			}
+		}
 		// fall through
 	case 3:
 		change.m_fRate = StringToFloat( aBGChangeValues[2] );

From 67bce173824e2ee99d858aa97145c6e1b3e81ff1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Sat, 13 Jun 2020 13:46:02 +0200
Subject: [PATCH 40/65] Extract logic to NoteDataUtil::StringInterpretsAs

---
 src/NoteDataUtil.cpp  | 11 +++++++++++
 src/NoteDataUtil.h    |  5 +++++
 src/NotesLoaderSM.cpp | 46 +++++++------------------------------------
 3 files changed, 23 insertions(+), 39 deletions(-)

diff --git a/src/NoteDataUtil.cpp b/src/NoteDataUtil.cpp
index 330b3f0b58..ee5e321258 100644
--- a/src/NoteDataUtil.cpp
+++ b/src/NoteDataUtil.cpp
@@ -11,6 +11,17 @@
 #include "TimingData.h"
 #include <utility>
 
+bool NoteDataUtil::StringInterpretsAs( const std::string& str, int integer ) {
+	try
+	{
+		return std::stoi( str ) == integer;
+	}
+	catch ( const std::invalid_argument & )
+	{
+		return false;
+	}
+}
+
 // TODO: Remove these constants that aren't time signature-aware
 static const int BEATS_PER_MEASURE = 4;
 static const int ROWS_PER_MEASURE = ROWS_PER_BEAT * BEATS_PER_MEASURE;
diff --git a/src/NoteDataUtil.h b/src/NoteDataUtil.h
index a855ddd2a6..8b9ea53432 100644
--- a/src/NoteDataUtil.h
+++ b/src/NoteDataUtil.h
@@ -23,6 +23,11 @@ void LightTransformHelper( const NoteData &in, NoteData &out, const vector<int>
  * and makes it much easier to change NoteData internally in the future. */
 namespace NoteDataUtil
 {
+	/**
+	 * @brief Whether a string can be interpreted as the provided signed integer
+	 */
+	bool StringInterpretsAs( const std::string& str, int integer );
+
 	NoteType GetSmallestNoteTypeForMeasure( const NoteData &nd, int iMeasureIndex );
 	NoteType GetSmallestNoteTypeInRange( const NoteData &nd, int iStartIndex, int iEndIndex );
 	void LoadFromSMNoteDataString( NoteData &out, const RString &sSMNoteData, bool bComposite );
diff --git a/src/NotesLoaderSM.cpp b/src/NotesLoaderSM.cpp
index fa2a6c0279..b0b52148a2 100644
--- a/src/NotesLoaderSM.cpp
+++ b/src/NotesLoaderSM.cpp
@@ -3,6 +3,7 @@
 #include "BackgroundUtil.h"
 #include "GameManager.h"
 #include "MsdFile.h"
+#include "NoteDataUtil.h"
 #include "NoteTypes.h"
 #include "RageFileManager.h"
 #include "RageLog.h"
@@ -974,58 +975,25 @@ bool SMLoader::LoadFromBGChangesVector( BackgroundChange &change, std::vector<RS
 	case 6:
 		// param 7 overrides this.
 		// Backward compatibility:
-		if( change.m_def.m_sEffect.empty() )
+		if( change.m_def.m_sEffect.empty() && !NoteDataUtil::StringInterpretsAs( aBGChangeValues[5], 0 ) )
 		{
-			try
-			{
-				if( std::stoi( aBGChangeValues[5] ) != 0 )
-				{
-					change.m_def.m_sEffect = SBE_StretchNoLoop;
-				}
-			}
-			catch ( const std::invalid_argument & )
-			{
-				// Failed conversions mean it's not 0 as well
-				change.m_def.m_sEffect = SBE_StretchNoLoop;
-			}
+			change.m_def.m_sEffect = SBE_StretchNoLoop;
 		}
 		// fall through
 	case 5:
 		// param 7 overrides this.
 		// Backward compatibility:
-		if( change.m_def.m_sEffect.empty() )
+		if( change.m_def.m_sEffect.empty() && !NoteDataUtil::StringInterpretsAs( aBGChangeValues[4], 0 ) )
 		{
-			try
-			{
-				if( std::stoi( aBGChangeValues[4] ) != 0 )
-				{
-					change.m_def.m_sEffect = SBE_StretchRewind;
-				}
-			}
-			catch ( const std::invalid_argument & )
-			{
-				// Failed conversions mean it's not 0 as well
-				change.m_def.m_sEffect = SBE_StretchRewind;
-			}
+			change.m_def.m_sEffect = SBE_StretchRewind;
 		}
 		// fall through
 	case 4:
 		// param 9 overrides this.
 		// Backward compatibility:
-		if( change.m_sTransition.empty() )
+		if( change.m_sTransition.empty() && !NoteDataUtil::StringInterpretsAs( aBGChangeValues[3], 0 ) )
 		{
-			try
-			{
-				if( std::stoi( aBGChangeValues[3] ) != 0 )
-				{
-					change.m_sTransition = SBT_CrossFade;
-				}
-			}
-			catch ( const std::invalid_argument & )
-			{
-				// Failed conversions mean it's not 0 as well
-				change.m_sTransition = SBT_CrossFade;
-			}
+			change.m_sTransition = SBT_CrossFade;
 		}
 		// fall through
 	case 3:

From 98e1a20cc3f9c35e1a9e11f2f6ad3c6fcecad830 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Sat, 13 Jun 2020 15:19:50 +0200
Subject: [PATCH 41/65] Don't disable exceptions on macOS

---
 src/CMakeLists.txt | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index f772ae3123..c29df4338d 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -247,8 +247,6 @@ elseif(APPLE)
       "${SM_XCODE_DIR}/plistHelper.hpp"
       XCODE_ATTRIBUTE_GCC_PREFIX_HEADER
       "${CMAKE_CURRENT_SOURCE_DIR}/archutils/Darwin/StepMania.pch"
-      XCODE_ATTRIBUTE_GCC_ENABLE_CPP_EXCEPTIONS
-      "NO"
       XCODE_ATTRIBUTE_LIBRARY_SEARCH_PATHS
       "${SM_XCODE_DIR}/Libraries")
 

From 6cb69c5e2a3a4c8eae8dbf3c946e37d19abf1646 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Sun, 14 Jun 2020 16:46:15 +0200
Subject: [PATCH 42/65] Actions Badge: Branch Fixup

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index fa9073e440..ab046f4553 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ StepMania is an advanced cross-platform rhythm game for home and arcade use.
 
 Advanced cross-platform rhythm game for home and arcade use.
 
-[![Continuous integration](https://github.com/stepmania/stepmania/workflows/Continuous%20integration/badge.svg?branch=master)](https://github.com/stepmania/stepmania/actions?query=workflow%3A%22Continuous+integration%22+branch%3Amaster)
+[![Continuous integration](https://github.com/stepmania/stepmania/workflows/Continuous%20integration/badge.svg?branch=5_1-new)](https://github.com/stepmania/stepmania/actions?query=workflow%3A%22Continuous+integration%22+branch%3A5_1-new)
 [![Build Status](https://travis-ci.org/stepmania/stepmania.svg?branch=master)](https://travis-ci.org/stepmania/stepmania)
 [![Build status](https://ci.appveyor.com/api/projects/status/uvoplsnyoats81r2?svg=true)](https://ci.appveyor.com/project/Nickito12/stepmania)
 

From 46f3e8aa9d081d5ab7ea10881439e0074db5caf3 Mon Sep 17 00:00:00 2001
From: Arusekk <arek_koz@o2.pl>
Date: Fri, 12 Jun 2020 00:53:17 +0200
Subject: [PATCH 43/65] Unix backtrace call detection

If the supposed return address is a pointer to the beginning of an
executable page, and the page before is an oversized file mapping,
like vvar before vdso, the backtrace would be terminated by SIGBUS.

To avoid this, check not for readable, but for executable instead.
---
 src/archutils/Unix/Backtrace.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/archutils/Unix/Backtrace.cpp b/src/archutils/Unix/Backtrace.cpp
index f55be5b130..fbf9a1c4d3 100644
--- a/src/archutils/Unix/Backtrace.cpp
+++ b/src/archutils/Unix/Backtrace.cpp
@@ -236,8 +236,7 @@ static bool PointsToValidCall( const void *ptr )
 	int len = 7;
 	while( len )
 	{
-		int val = find_address( buf-len, g_ReadableBegin, g_ReadableEnd );
-		if( val != -1 )
+		if( IsExecutableAddress( buf - len ) )
 			break;
 		--len;
 	}

From 76f805fe9cbbdf3edd20863381dde6fb5b6120f1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Thu, 18 Jun 2020 20:35:17 +0200
Subject: [PATCH 44/65] jsoncpp: Reset existing files to svn-release-0.5.0

---
 extern/jsoncpp/include/json/value.h         | 7 -------
 extern/jsoncpp/src/lib_json/json_reader.cpp | 7 +++----
 extern/jsoncpp/src/lib_json/json_value.cpp  | 6 +++---
 extern/jsoncpp/src/lib_json/json_writer.cpp | 8 ++++----
 4 files changed, 10 insertions(+), 18 deletions(-)

diff --git a/extern/jsoncpp/include/json/value.h b/extern/jsoncpp/include/json/value.h
index 0cf4ca76cf..58bfd88e7a 100644
--- a/extern/jsoncpp/include/json/value.h
+++ b/extern/jsoncpp/include/json/value.h
@@ -234,13 +234,6 @@ namespace Json {
       double asDouble() const;
       bool asBool() const;
 
-      bool TryGet( std::string &out ) const { if(!isString()) return false; out=asString(); return true; }
-      bool TryGet( int &out ) const { if(!isInt()) return false; out=asInt(); return true; }
-      bool TryGet( UInt &out ) const { if(!isUInt()) return false; out=asUInt(); return true; }
-      bool TryGet( double &out ) const { if(!isDouble()) return false; out=asDouble(); return true; }
-      bool TryGet( float &out ) const { if(!isDouble()) return false; out=(float)asDouble(); return true; }
-      bool TryGet( bool &out ) const { if(!isBool()) return false; out=asBool(); return true; }
-
       bool isNull() const;
       bool isBool() const;
       bool isInt() const;
diff --git a/extern/jsoncpp/src/lib_json/json_reader.cpp b/extern/jsoncpp/src/lib_json/json_reader.cpp
index 3e79ab733e..4eb2d11fd3 100644
--- a/extern/jsoncpp/src/lib_json/json_reader.cpp
+++ b/extern/jsoncpp/src/lib_json/json_reader.cpp
@@ -1,5 +1,5 @@
-#include "json/reader.h"
-#include "json/value.h"
+#include <json/reader.h>
+#include <json/value.h>
 #include <utility>
 #include <cstdio>
 #include <cassert>
@@ -877,8 +877,7 @@ std::istream& operator>>( std::istream &sin, Value &root )
     Json::Reader reader;
     bool ok = reader.parse(sin, root, true);
     //JSON_ASSERT( ok );
-//    if (!ok) throw std::runtime_error(reader.getFormatedErrorMessages());
-    assert(ok);
+    if (!ok) throw std::runtime_error(reader.getFormatedErrorMessages());
     return sin;
 }
 
diff --git a/extern/jsoncpp/src/lib_json/json_value.cpp b/extern/jsoncpp/src/lib_json/json_value.cpp
index 1ecacd45d0..573205f13e 100644
--- a/extern/jsoncpp/src/lib_json/json_value.cpp
+++ b/extern/jsoncpp/src/lib_json/json_value.cpp
@@ -1,6 +1,6 @@
 #include <iostream>
-#include "json/value.h"
-#include "json/writer.h"
+#include <json/value.h>
+#include <json/writer.h>
 #include <utility>
 #include <stdexcept>
 #include <cstring>
@@ -15,7 +15,7 @@
 
 #define JSON_ASSERT_UNREACHABLE assert( false )
 #define JSON_ASSERT( condition ) assert( condition );  // @todo <= change this into an exception throw
-#define JSON_ASSERT_MESSAGE( condition, message ) if (!( condition )) assert(false); /* throw std::runtime_error( message ); */
+#define JSON_ASSERT_MESSAGE( condition, message ) if (!( condition )) throw std::runtime_error( message );
 
 namespace Json {
 
diff --git a/extern/jsoncpp/src/lib_json/json_writer.cpp b/extern/jsoncpp/src/lib_json/json_writer.cpp
index 8412670e2f..cdf4188f2e 100644
--- a/extern/jsoncpp/src/lib_json/json_writer.cpp
+++ b/extern/jsoncpp/src/lib_json/json_writer.cpp
@@ -1,4 +1,4 @@
-#include "json/writer.h"
+#include <json/writer.h>
 #include <utility>
 #include <assert.h>
 #include <stdio.h>
@@ -111,7 +111,7 @@ std::string valueToString( bool value )
 std::string valueToQuotedString( const char *value )
 {
    // Not sure how to handle unicode...
-   if (strpbrk(value, "\"\\\b\f\n\r\t") == nullptr && !containsControlCharacter( value ))
+   if (strpbrk(value, "\"\\\b\f\n\r\t") == NULL && !containsControlCharacter( value ))
       return std::string("\"") + value + "\"";
    // We have to walk value and escape any special characters.
    // Appending to std::string is not efficient, but this should be rare.
@@ -542,7 +542,7 @@ StyledWriter::normalizeEOL( const std::string &text )
 // //////////////////////////////////////////////////////////////////
 
 StyledStreamWriter::StyledStreamWriter( std::string indentation )
-   : document_(nullptr)
+   : document_(NULL)
    , rightMargin_( 74 )
    , indentation_( indentation )
 {
@@ -559,7 +559,7 @@ StyledStreamWriter::write( std::ostream &out, const Value &root )
    writeValue( root );
    writeCommentAfterValueOnSameLine( root );
    *document_ << "\n";
-   document_ = nullptr; // Forget the stream, for safety.
+   document_ = NULL; // Forget the stream, for safety.
 }
 
 

From f075d6a6176ca8906b5d34da61b841aa069fd26c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Thu, 18 Jun 2020 20:56:40 +0200
Subject: [PATCH 45/65] JsonUtil: Adapt functions to vanilla jsoncpp

---
 src/JsonUtil.cpp        | 13 ++++++++
 src/JsonUtil.h          | 69 ++---------------------------------------
 src/NotesLoaderJson.cpp |  2 +-
 3 files changed, 16 insertions(+), 68 deletions(-)

diff --git a/src/JsonUtil.cpp b/src/JsonUtil.cpp
index 755036e770..33e97e6cd2 100644
--- a/src/JsonUtil.cpp
+++ b/src/JsonUtil.cpp
@@ -75,6 +75,19 @@ bool JsonUtil::WriteFile(const Json::Value &root, const RString &sFile, bool bMi
 	return true;
 }
 
+std::vector<RString> JsonUtil::DeserializeArrayStrings(const Json::Value &value)
+{
+	std::vector<RString> values;
+	for(auto &&inner_value : value)
+	{
+		if(inner_value.isConvertibleTo(Json::stringValue))
+		{
+			values.push_back(inner_value.asString());
+		}
+	}
+	return values;
+}
+
 /*
  * (c) 2001-2004 Chris Danford
  * All rights reserved.
diff --git a/src/JsonUtil.h b/src/JsonUtil.h
index 3cb1bdf673..582f91e342 100644
--- a/src/JsonUtil.h
+++ b/src/JsonUtil.h
@@ -14,6 +14,8 @@ namespace JsonUtil
 
 	bool WriteFile(const Json::Value &root, const RString &sFile, bool bMinified);
 
+	std::vector<RString> DeserializeArrayStrings(const Json::Value &array);
+
 	template<class T>
 	static void SerializeVectorObjects(const vector<T> &v, void fn(const T &, Json::Value &), Json::Value &root)
 	{
@@ -195,57 +197,6 @@ namespace JsonUtil
 		}
 	}
 
-	template<class T>
-	static void DeserializeArrayValues(vector<T> &v, const Json::Value &root)
-	{
-		v.clear();
-		for( unsigned i=0; i<root.size(); i++ )
-		{
-			T t;
-			if( root[i].TryGet( t ) )
-				v.push_back( t );
-		}
-	}
-
-	// don't pull in the set header here
-	template<typename S, typename T>
-	static void DeserializeArrayValuesIntoSet(S &s, const Json::Value &root)
-	{
-		s.clear();
-		for( unsigned i=0; i<root.size(); i++ )
-		{
-			T t;
-			if( root[i].TryGet( t ) )
-				s.insert( t );
-		}
-	}
-
-	template<typename T>
-	static void DeserializeArrayValuesIntoVector(vector<T> &v, const Json::Value &root)
-	{
-		v.clear();
-		for( unsigned i=0; i<root.size(); i++ )
-		{
-			T t;
-			if( root[i].TryGet( t ) )
-				v.push_back( t );
-		}
-	}
-
-	template <typename M>
-	static void DeserializeValueToValueMap(M &m, const Json::Value &root)
-	{
-		for( Json::Value::const_iterator iter = root.begin(); iter != root.end(); iter++ )
-			(*iter).TryGet( m[ iter.memberName() ] );
-	}
-
-	template <typename M, typename E, typename F>
-	static void DeserializeStringToValueMap(M &m, F fnToValue(E e), const Json::Value &root)
-	{
-		for( Json::Value::const_iterator iter = root.begin(); iter != root.end(); iter++ )
-			(*iter).TryGet( m[ fnToValue(iter.memberName()) ] );
-	}
-
 	template <typename M, typename E, typename F>
 	static void DeserializeStringToObjectMap(M &m, F fnToValue(E e), const Json::Value &root)
 	{
@@ -272,22 +223,6 @@ namespace JsonUtil
 		}
 	}
 
-	template <typename K, typename V>
-	static void DeserializeObjectToValueMapAsArray(map<K,V> &m, const RString &sKeyName, const RString &sValueName, const Json::Value &root)
-	{
-		for( unsigned i=0; i<root.size(); i++ )
-		{
-			const Json::Value &root2 = root[i];
-			K k;
-			if( !k.Deserialize( root2[sKeyName] ) )
-				continue;
-			V v;
-			if( !root2[sValueName].TryGet(v) )
-				continue;
-			m[k] = v;
-		}
-	}
-
 	template<class T>
 	static void DeserializeVectorValues(vector<T> &v, const Json::Value &root)
 	{
diff --git a/src/NotesLoaderJson.cpp b/src/NotesLoaderJson.cpp
index 18d2486bb8..b7c38405f1 100644
--- a/src/NotesLoaderJson.cpp
+++ b/src/NotesLoaderJson.cpp
@@ -214,7 +214,7 @@ static void Deserialize( Song &out, const Json::Value &root )
 		JsonUtil::DeserializeVectorObjects( vBgc, Deserialize, root["ForegroundChanges"] );
 	}
 
-	JsonUtil::DeserializeArrayValuesIntoVector( out.m_vsKeysoundFile, root["KeySounds"] );
+	out.m_vsKeysoundFile = JsonUtil::DeserializeArrayStrings(root["KeySounds"]);
 
 	{
 		vector<Steps*> vpSteps;

From 4ef5078b2da1045a7090379ab8ee81c8f2f3d2e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Thu, 18 Jun 2020 21:56:58 +0200
Subject: [PATCH 46/65] CI: Test system jsoncpp

---
 .github/workflows/ci.yml | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c753c82a09..8c153b0af6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -55,14 +55,13 @@ jobs:
           libxtst-dev
           ninja-build
       - name: Configure
-        # TODO: jsoncpp: https://github.com/stepmania/stepmania/issues/1883
         # TODO: png: https://github.com/stepmania/stepmania/issues/1881
         # TODO: tomcrypt: https://github.com/stepmania/stepmania/issues/1885
         run: cmake -G Ninja -B build
           -DWITH_SYSTEM_FFMPEG=ON
           -DWITH_SYSTEM_GLEW=ON
           -DWITH_SYSTEM_JPEG=ON
-          -DWITH_SYSTEM_JSONCPP=OFF
+          -DWITH_SYSTEM_JSONCPP=ON
           -DWITH_SYSTEM_MAD=ON
           -DWITH_SYSTEM_OGG=ON
           -DWITH_SYSTEM_PCRE=ON

From 960c57c4f303f3396d0a851c247bab3fa22a82cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <m.kroening@hotmail.de>
Date: Sun, 8 Sep 2019 12:51:36 +0200
Subject: [PATCH 47/65] Only add bundled inc dirs, when using bundled libs

Fixes #1881
---
 src/CMakeLists.txt             | 23 +++++++++++++++++------
 src/CMakeProject-texture.cmake | 12 ++++++++++--
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index c29df4338d..6e0f28e364 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -612,10 +612,21 @@ list(APPEND SM_INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}
             "${SM_SRC_DIR}/generated")
 list(APPEND SM_INCLUDE_DIRS "${JPEG_INCLUDE_DIR}")
 if(NOT APPLE)
-  list(APPEND SM_INCLUDE_DIRS
-              "${SM_EXTERN_DIR}/glew-1.5.8/include"
-              "${SM_EXTERN_DIR}/jsoncpp/include"
-              "${SM_EXTERN_DIR}/zlib")
+  if(NOT WITH_SYSTEM_GLEW)
+    list(APPEND SM_INCLUDE_DIRS
+                "${SM_EXTERN_DIR}/glew-1.5.8/include")
+  endif()
+
+  if(NOT WITH_SYSTEM_JSONCPP)
+    list(APPEND SM_INCLUDE_DIRS
+                "${SM_EXTERN_DIR}/jsoncpp/include")
+  endif()
+
+  if(NOT WITH_SYSTEM_ZLIB)
+    list(APPEND SM_INCLUDE_DIRS
+                "${SM_EXTERN_DIR}/zlib")
+  endif()
+
   if(MSVC)
     if(WITH_OGG)
       list(APPEND SM_INCLUDE_DIRS
@@ -625,7 +636,7 @@ if(NOT APPLE)
     endif()
     list(APPEND SM_INCLUDE_DIRS "${SM_EXTERN_DIR}/ffmpeg/include")
   else()
-    if(WITH_OGG)
+    if(WITH_OGG AND NOT WITH_SYSTEM_OGG)
       list(APPEND SM_INCLUDE_DIRS "${SM_EXTERN_DIR}/vorbis")
     endif()
     if(HAS_FFMPEG)
@@ -664,7 +675,7 @@ endif()
 if(WIN32)
   # FIXME: This makes no sense...
   #list(APPEND SM_INCLUDE_DIRS ${DIRECTX_INCLUDE_DIR})
-else()
+elseif(NOT WITH_SYSTEM_PNG)
   list(APPEND SM_INCLUDE_DIRS "${SM_EXTERN_DIR}/libpng/include")
 endif()
 
diff --git a/src/CMakeProject-texture.cmake b/src/CMakeProject-texture.cmake
index 70ccd5ab16..c46cbe14f0 100644
--- a/src/CMakeProject-texture.cmake
+++ b/src/CMakeProject-texture.cmake
@@ -50,10 +50,18 @@ target_link_libraries("TextureFontGenerator" ${TEXTURE_LINK_LIB})
 list(APPEND TEXTURE_INCLUDE_DIRS
             "${TEXTURE_DIR}"
             "${TEXTURE_DIR}/res"
-            "${SM_EXTERN_DIR}/zlib"
-            "${SM_EXTERN_DIR}/libpng/include"
             "${SM_SRC_DIR}/generated")
 
+if(NOT WITH_SYSTEM_ZLIB)
+  list(APPEND TEXTURE_INCLUDE_DIRS
+              "${SM_EXTERN_DIR}/zlib")
+endif()
+
+if(NOT WITH_SYSTEM_PNG)
+  list(APPEND TEXTURE_INCLUDE_DIRS
+              "${SM_EXTERN_DIR}/libpng/include")
+endif()
+
 target_include_directories("TextureFontGenerator"
                            PUBLIC ${TEXTURE_INCLUDE_DIRS})
 

From 092cffa1823e7d046be09ccc846f2ed7f7a7e95a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Thu, 18 Jun 2020 23:15:44 +0200
Subject: [PATCH 48/65] Find system jsoncpp via pkg-config, add system include

---
 extern/CMakeProject-json.cmake | 6 ++----
 src/CMakeLists.txt             | 6 ++++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/extern/CMakeProject-json.cmake b/extern/CMakeProject-json.cmake
index ec133ea2be..953a8d82d4 100644
--- a/extern/CMakeProject-json.cmake
+++ b/extern/CMakeProject-json.cmake
@@ -1,8 +1,6 @@
 if(WITH_SYSTEM_JSONCPP)
-  find_library(JSONCPP_LIBRARY jsoncpp)
-  if(JSONCPP_LIBRARY MATCHES "JSONCPP_LIBRARY-NOTFOUND")
-    message(FATAL_ERROR "Need jsoncpp.")
-  endif()
+  find_package(PkgConfig REQUIRED)
+  pkg_check_modules(JSONCPP REQUIRED jsoncpp)
 else()
   list(APPEND JSON_SRC
               "jsoncpp/src/lib_json/json_reader.cpp"
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 6e0f28e364..72cb54a493 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -449,7 +449,7 @@ else()
 endif()
 
 if(WITH_SYSTEM_JSONCPP)
-  list(APPEND SMDATA_LINK_LIB ${JSONCPP_LIBRARY})
+  list(APPEND SMDATA_LINK_LIB ${JSONCPP_LIBRARIES})
 else()
   list(APPEND SMDATA_LINK_LIB "jsoncpp")
 endif()
@@ -617,7 +617,9 @@ if(NOT APPLE)
                 "${SM_EXTERN_DIR}/glew-1.5.8/include")
   endif()
 
-  if(NOT WITH_SYSTEM_JSONCPP)
+  if(WITH_SYSTEM_JSONCPP)
+    list(APPEND SM_INCLUDE_DIRS ${JSONCPP_INCLUDE_DIRS})
+  else()
     list(APPEND SM_INCLUDE_DIRS
                 "${SM_EXTERN_DIR}/jsoncpp/include")
   endif()

From d4caf2c8f85a806ae036fc5dfb93eb0b9742b86e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Fri, 19 Jun 2020 00:04:28 +0200
Subject: [PATCH 49/65] Replace in-tree libpng 1.5.10 src with submodule at tag
 v1.5.30

---
 .gitmodules                                   |    3 +
 extern/libpng                                 |    1 +
 extern/libpng/include/ANNOUNCE                |   64 -
 extern/libpng/include/CHANGES                 | 3864 -------
 extern/libpng/include/CMakeLists.txt          |  340 -
 extern/libpng/include/INSTALL                 |  155 -
 extern/libpng/include/LICENSE                 |  111 -
 extern/libpng/include/Makefile.am             |  228 -
 extern/libpng/include/README                  |  202 -
 extern/libpng/include/TODO                    |   27 -
 extern/libpng/include/autogen.sh              |   34 -
 extern/libpng/include/config.guess            | 1522 ---
 extern/libpng/include/config.h.in             |  109 -
 extern/libpng/include/config.sub              | 1771 ---
 extern/libpng/include/configure.ac            |  204 -
 extern/libpng/include/contrib/README.txt      |    4 -
 .../libpng/include/contrib/gregbook/COPYING   |  340 -
 .../libpng/include/contrib/gregbook/LICENSE   |   50 -
 .../include/contrib/gregbook/Makefile.mingw32 |  130 -
 .../include/contrib/gregbook/Makefile.sgi     |  104 -
 .../include/contrib/gregbook/Makefile.unx     |  132 -
 .../include/contrib/gregbook/Makefile.w32     |  113 -
 extern/libpng/include/contrib/gregbook/README |  186 -
 .../include/contrib/gregbook/makevms.com      |  132 -
 .../libpng/include/contrib/gregbook/readpng.c |  311 -
 .../libpng/include/contrib/gregbook/readpng.h |   88 -
 .../include/contrib/gregbook/readpng2.c       |  511 -
 .../include/contrib/gregbook/readpng2.h       |  116 -
 .../libpng/include/contrib/gregbook/readppm.c |  179 -
 .../include/contrib/gregbook/rpng-win.c       |  728 --
 .../libpng/include/contrib/gregbook/rpng-x.c  |  904 --
 .../include/contrib/gregbook/rpng2-win.c      | 1253 ---
 .../libpng/include/contrib/gregbook/rpng2-x.c | 2107 ----
 .../include/contrib/gregbook/toucan.png       |  Bin 12901 -> 0 bytes
 extern/libpng/include/contrib/gregbook/wpng.c |  853 --
 .../include/contrib/gregbook/writepng.c       |  400 -
 .../include/contrib/gregbook/writepng.h       |  133 -
 .../include/contrib/libtests/pngvalid.c       | 9837 -----------------
 extern/libpng/include/contrib/pngminim/README |    4 -
 .../include/contrib/pngminim/decoder/README   |   10 -
 .../include/contrib/pngminim/decoder/makefile |  150 -
 .../contrib/pngminim/decoder/pngusr.dfa       |   39 -
 .../include/contrib/pngminim/decoder/pngusr.h |   24 -
 .../include/contrib/pngminim/encoder/README   |   10 -
 .../include/contrib/pngminim/encoder/makefile |  149 -
 .../contrib/pngminim/encoder/pngusr.dfa       |   35 -
 .../include/contrib/pngminim/encoder/pngusr.h |   24 -
 .../include/contrib/pngminim/preader/README   |   15 -
 .../include/contrib/pngminim/preader/makefile |  165 -
 .../contrib/pngminim/preader/pngusr.dfa       |   40 -
 .../include/contrib/pngminim/preader/pngusr.h |   24 -
 extern/libpng/include/contrib/pngminus/README |  153 -
 .../include/contrib/pngminus/makefile.std     |   65 -
 .../include/contrib/pngminus/makefile.tc3     |   38 -
 .../include/contrib/pngminus/makevms.com      |   92 -
 .../include/contrib/pngminus/png2pnm.bat      |   41 -
 .../libpng/include/contrib/pngminus/png2pnm.c |  430 -
 .../include/contrib/pngminus/png2pnm.sh       |   42 -
 .../include/contrib/pngminus/pngminus.bat     |    4 -
 .../include/contrib/pngminus/pngminus.sh      |    5 -
 .../include/contrib/pngminus/pnm2png.bat      |   41 -
 .../libpng/include/contrib/pngminus/pnm2png.c |  533 -
 .../include/contrib/pngminus/pnm2png.sh       |   42 -
 extern/libpng/include/contrib/pngsuite/README |  102 -
 .../include/contrib/pngsuite/basn0g01.png     |  Bin 164 -> 0 bytes
 .../include/contrib/pngsuite/basn0g02.png     |  Bin 104 -> 0 bytes
 .../include/contrib/pngsuite/basn0g04.png     |  Bin 145 -> 0 bytes
 .../include/contrib/pngsuite/basn0g08.png     |  Bin 138 -> 0 bytes
 .../include/contrib/pngsuite/basn0g16.png     |  Bin 167 -> 0 bytes
 .../include/contrib/pngsuite/basn2c08.png     |  Bin 145 -> 0 bytes
 .../include/contrib/pngsuite/basn2c16.png     |  Bin 302 -> 0 bytes
 .../include/contrib/pngsuite/basn3p01.png     |  Bin 112 -> 0 bytes
 .../include/contrib/pngsuite/basn3p02.png     |  Bin 146 -> 0 bytes
 .../include/contrib/pngsuite/basn3p04.png     |  Bin 216 -> 0 bytes
 .../include/contrib/pngsuite/basn3p08.png     |  Bin 1286 -> 0 bytes
 .../include/contrib/pngsuite/basn4a08.png     |  Bin 126 -> 0 bytes
 .../include/contrib/pngsuite/basn4a16.png     |  Bin 2206 -> 0 bytes
 .../include/contrib/pngsuite/basn6a08.png     |  Bin 184 -> 0 bytes
 .../include/contrib/pngsuite/basn6a16.png     |  Bin 3435 -> 0 bytes
 .../include/contrib/pngsuite/ftbbn1g04.png    |  Bin 429 -> 0 bytes
 .../include/contrib/pngsuite/ftbbn2c16.png    |  Bin 2041 -> 0 bytes
 .../include/contrib/pngsuite/ftbbn3p08.png    |  Bin 1499 -> 0 bytes
 .../include/contrib/pngsuite/ftbgn2c16.png    |  Bin 2041 -> 0 bytes
 .../include/contrib/pngsuite/ftbgn3p08.png    |  Bin 1499 -> 0 bytes
 .../include/contrib/pngsuite/ftbrn2c08.png    |  Bin 1633 -> 0 bytes
 .../include/contrib/pngsuite/ftbwn1g16.png    |  Bin 1313 -> 0 bytes
 .../include/contrib/pngsuite/ftbwn3p08.png    |  Bin 1496 -> 0 bytes
 .../include/contrib/pngsuite/ftbyn3p08.png    |  Bin 1499 -> 0 bytes
 .../include/contrib/pngsuite/ftp0n1g08.png    |  Bin 719 -> 0 bytes
 .../include/contrib/pngsuite/ftp0n2c08.png    |  Bin 1594 -> 0 bytes
 .../include/contrib/pngsuite/ftp0n3p08.png    |  Bin 1476 -> 0 bytes
 .../include/contrib/pngsuite/ftp1n3p08.png    |  Bin 1483 -> 0 bytes
 .../libpng/include/contrib/visupng/PngFile.c  |  450 -
 .../libpng/include/contrib/visupng/PngFile.h  |   30 -
 .../libpng/include/contrib/visupng/README.txt |   61 -
 .../include/contrib/visupng/VisualPng.c       |  969 --
 .../include/contrib/visupng/VisualPng.dsp     |  147 -
 .../include/contrib/visupng/VisualPng.dsw     |   29 -
 .../include/contrib/visupng/VisualPng.ico     |  Bin 766 -> 0 bytes
 .../include/contrib/visupng/VisualPng.png     |  Bin 208 -> 0 bytes
 .../include/contrib/visupng/VisualPng.rc      |  152 -
 .../libpng/include/contrib/visupng/cexcept.h  |  248 -
 .../libpng/include/contrib/visupng/resource.h |   23 -
 extern/libpng/include/depcomp                 |  688 --
 extern/libpng/include/example.c               |  875 --
 extern/libpng/include/libpng-config.in        |  127 -
 extern/libpng/include/libpng-manual.txt       | 4652 --------
 extern/libpng/include/libpng.3                | 5982 ----------
 extern/libpng/include/libpng.pc.in            |   11 -
 extern/libpng/include/libpngpf.3              |   28 -
 extern/libpng/include/ltmain.sh               | 9655 ----------------
 extern/libpng/include/missing                 |  376 -
 extern/libpng/include/png.5                   |   74 -
 extern/libpng/include/png.c                   | 2874 -----
 extern/libpng/include/png.h                   | 2666 -----
 extern/libpng/include/pngbar.jpg              |  Bin 2498 -> 0 bytes
 extern/libpng/include/pngbar.png              |  Bin 2399 -> 0 bytes
 extern/libpng/include/pngconf.h               |  596 -
 extern/libpng/include/pngdebug.h              |  157 -
 extern/libpng/include/pngerror.c              |  685 --
 extern/libpng/include/pngget.c                | 1124 --
 extern/libpng/include/pnginfo.h               |  269 -
 extern/libpng/include/pnglibconf.h            |  186 -
 extern/libpng/include/pngmem.c                |  667 --
 extern/libpng/include/pngnow.png              |  Bin 2069 -> 0 bytes
 extern/libpng/include/pngpread.c              | 1314 ---
 extern/libpng/include/pngpriv.h               | 1677 ---
 extern/libpng/include/pngread.c               | 1305 ---
 extern/libpng/include/pngrio.c                |  176 -
 extern/libpng/include/pngrtran.c              | 5032 ---------
 extern/libpng/include/pngrutil.c              | 4159 -------
 extern/libpng/include/pngset.c                | 1309 ---
 extern/libpng/include/pngstruct.h             |  357 -
 extern/libpng/include/pngtest.c               | 1820 ---
 extern/libpng/include/pngtest.png             |  Bin 8695 -> 0 bytes
 extern/libpng/include/pngtrans.c              |  781 --
 extern/libpng/include/pngusr.dfa              |   14 -
 extern/libpng/include/pngvalid.c              | 6658 -----------
 extern/libpng/include/pngwio.c                |  254 -
 extern/libpng/include/pngwrite.c              | 1667 ---
 extern/libpng/include/pngwtran.c              |  633 --
 extern/libpng/include/pngwutil.c              | 3179 ------
 .../include/projects/owatcom/libpng.tgt       |  383 -
 .../include/projects/owatcom/libpng.wpj       |   92 -
 .../include/projects/owatcom/pngconfig.mak    |  160 -
 .../include/projects/owatcom/pngtest.tgt      |  179 -
 .../include/projects/owatcom/pngvalid.tgt     |  210 -
 .../include/projects/visualc71/PRJ0041.mak    |   21 -
 .../include/projects/visualc71/README.txt     |   58 -
 .../projects/visualc71/README_zlib.txt        |   44 -
 .../include/projects/visualc71/libpng.sln     |   60 -
 .../include/projects/visualc71/libpng.vcproj  |  419 -
 .../include/projects/visualc71/pngtest.vcproj |  267 -
 .../include/projects/visualc71/zlib.vcproj    |  391 -
 .../projects/vstudio/libpng/libpng.vcxproj    |  233 -
 .../vstudio/pnglibconf/pnglibconf.vcxproj     |   60 -
 .../projects/vstudio/pngtest/pngtest.vcxproj  |  219 -
 .../vstudio/pngvalid/pngvalid.vcxproj         |  218 -
 .../include/projects/vstudio/readme.txt       |   64 -
 .../include/projects/vstudio/vstudio.sln      |   87 -
 .../include/projects/vstudio/zlib.props       |   37 -
 .../projects/vstudio/zlib/zlib.vcxproj        |  174 -
 extern/libpng/include/scripts/README.txt      |   76 -
 extern/libpng/include/scripts/SCOPTIONS.ppc   |    7 -
 extern/libpng/include/scripts/checksym.awk    |  161 -
 extern/libpng/include/scripts/chkfmt          |  137 -
 extern/libpng/include/scripts/def.dfn         |   38 -
 extern/libpng/include/scripts/descrip.mms     |   52 -
 .../include/scripts/libpng-config-body.in     |   96 -
 .../include/scripts/libpng-config-head.in     |   24 -
 extern/libpng/include/scripts/libpng.pc.in    |   10 -
 extern/libpng/include/scripts/makefile.32sunu |  241 -
 extern/libpng/include/scripts/makefile.64sunu |  241 -
 extern/libpng/include/scripts/makefile.acorn  |   57 -
 extern/libpng/include/scripts/makefile.aix    |  121 -
 extern/libpng/include/scripts/makefile.amiga  |   56 -
 extern/libpng/include/scripts/makefile.atari  |   63 -
 extern/libpng/include/scripts/makefile.bc32   |  151 -
 extern/libpng/include/scripts/makefile.beos   |  215 -
 extern/libpng/include/scripts/makefile.bor    |  161 -
 extern/libpng/include/scripts/makefile.cegcc  |  116 -
 extern/libpng/include/scripts/makefile.darwin |  220 -
 extern/libpng/include/scripts/makefile.dec    |  202 -
 extern/libpng/include/scripts/makefile.dj2    |   62 -
 extern/libpng/include/scripts/makefile.elf    |  263 -
 .../libpng/include/scripts/makefile.freebsd   |   53 -
 extern/libpng/include/scripts/makefile.gcc    |   87 -
 extern/libpng/include/scripts/makefile.hp64   |  224 -
 extern/libpng/include/scripts/makefile.hpgcc  |  230 -
 extern/libpng/include/scripts/makefile.hpux   |  221 -
 extern/libpng/include/scripts/makefile.ibmc   |   82 -
 extern/libpng/include/scripts/makefile.intel  |  110 -
 extern/libpng/include/scripts/makefile.knr    |  109 -
 extern/libpng/include/scripts/makefile.linux  |  239 -
 extern/libpng/include/scripts/makefile.mips   |   94 -
 extern/libpng/include/scripts/makefile.msc    |   95 -
 .../libpng/include/scripts/makefile.ne12bsd   |   50 -
 extern/libpng/include/scripts/makefile.netbsd |   50 -
 .../libpng/include/scripts/makefile.openbsd   |   82 -
 extern/libpng/include/scripts/makefile.sco    |  218 -
 extern/libpng/include/scripts/makefile.sggcc  |  228 -
 extern/libpng/include/scripts/makefile.sgi    |  229 -
 extern/libpng/include/scripts/makefile.so9    |  239 -
 .../libpng/include/scripts/makefile.solaris   |  236 -
 .../include/scripts/makefile.solaris-x86      |  236 -
 extern/libpng/include/scripts/makefile.std    |  123 -
 extern/libpng/include/scripts/makefile.sunos  |  107 -
 extern/libpng/include/scripts/makefile.tc3    |   93 -
 .../libpng/include/scripts/makefile.vcwin32   |  108 -
 extern/libpng/include/scripts/makevms.com     |  142 -
 extern/libpng/include/scripts/options.awk     |  777 --
 extern/libpng/include/scripts/pnglibconf.dfa  |  590 -
 .../include/scripts/pnglibconf.h.prebuilt     |  186 -
 extern/libpng/include/scripts/pnglibconf.mak  |   58 -
 extern/libpng/include/scripts/pngwin.rc       |  112 -
 extern/libpng/include/scripts/smakefile.ppc   |   34 -
 extern/libpng/include/scripts/sym.dfn         |   15 -
 extern/libpng/include/scripts/symbols.def     |  242 -
 extern/libpng/include/scripts/symbols.dfn     |   57 -
 extern/libpng/include/scripts/vers.dfn        |   26 -
 extern/libpng/include/test-pngtest.sh         |   16 -
 extern/libpng/include/test-pngvalid-full.sh   |   21 -
 extern/libpng/include/test-pngvalid-simple.sh |   30 -
 223 files changed, 4 insertions(+), 105650 deletions(-)
 create mode 100644 .gitmodules
 create mode 160000 extern/libpng
 delete mode 100644 extern/libpng/include/ANNOUNCE
 delete mode 100644 extern/libpng/include/CHANGES
 delete mode 100644 extern/libpng/include/CMakeLists.txt
 delete mode 100644 extern/libpng/include/INSTALL
 delete mode 100644 extern/libpng/include/LICENSE
 delete mode 100644 extern/libpng/include/Makefile.am
 delete mode 100644 extern/libpng/include/README
 delete mode 100644 extern/libpng/include/TODO
 delete mode 100755 extern/libpng/include/autogen.sh
 delete mode 100644 extern/libpng/include/config.guess
 delete mode 100644 extern/libpng/include/config.h.in
 delete mode 100644 extern/libpng/include/config.sub
 delete mode 100644 extern/libpng/include/configure.ac
 delete mode 100644 extern/libpng/include/contrib/README.txt
 delete mode 100644 extern/libpng/include/contrib/gregbook/COPYING
 delete mode 100644 extern/libpng/include/contrib/gregbook/LICENSE
 delete mode 100644 extern/libpng/include/contrib/gregbook/Makefile.mingw32
 delete mode 100644 extern/libpng/include/contrib/gregbook/Makefile.sgi
 delete mode 100644 extern/libpng/include/contrib/gregbook/Makefile.unx
 delete mode 100644 extern/libpng/include/contrib/gregbook/Makefile.w32
 delete mode 100644 extern/libpng/include/contrib/gregbook/README
 delete mode 100644 extern/libpng/include/contrib/gregbook/makevms.com
 delete mode 100644 extern/libpng/include/contrib/gregbook/readpng.c
 delete mode 100644 extern/libpng/include/contrib/gregbook/readpng.h
 delete mode 100644 extern/libpng/include/contrib/gregbook/readpng2.c
 delete mode 100644 extern/libpng/include/contrib/gregbook/readpng2.h
 delete mode 100644 extern/libpng/include/contrib/gregbook/readppm.c
 delete mode 100644 extern/libpng/include/contrib/gregbook/rpng-win.c
 delete mode 100644 extern/libpng/include/contrib/gregbook/rpng-x.c
 delete mode 100644 extern/libpng/include/contrib/gregbook/rpng2-win.c
 delete mode 100644 extern/libpng/include/contrib/gregbook/rpng2-x.c
 delete mode 100644 extern/libpng/include/contrib/gregbook/toucan.png
 delete mode 100644 extern/libpng/include/contrib/gregbook/wpng.c
 delete mode 100644 extern/libpng/include/contrib/gregbook/writepng.c
 delete mode 100644 extern/libpng/include/contrib/gregbook/writepng.h
 delete mode 100644 extern/libpng/include/contrib/libtests/pngvalid.c
 delete mode 100644 extern/libpng/include/contrib/pngminim/README
 delete mode 100644 extern/libpng/include/contrib/pngminim/decoder/README
 delete mode 100644 extern/libpng/include/contrib/pngminim/decoder/makefile
 delete mode 100644 extern/libpng/include/contrib/pngminim/decoder/pngusr.dfa
 delete mode 100644 extern/libpng/include/contrib/pngminim/decoder/pngusr.h
 delete mode 100644 extern/libpng/include/contrib/pngminim/encoder/README
 delete mode 100644 extern/libpng/include/contrib/pngminim/encoder/makefile
 delete mode 100644 extern/libpng/include/contrib/pngminim/encoder/pngusr.dfa
 delete mode 100644 extern/libpng/include/contrib/pngminim/encoder/pngusr.h
 delete mode 100644 extern/libpng/include/contrib/pngminim/preader/README
 delete mode 100644 extern/libpng/include/contrib/pngminim/preader/makefile
 delete mode 100644 extern/libpng/include/contrib/pngminim/preader/pngusr.dfa
 delete mode 100644 extern/libpng/include/contrib/pngminim/preader/pngusr.h
 delete mode 100644 extern/libpng/include/contrib/pngminus/README
 delete mode 100644 extern/libpng/include/contrib/pngminus/makefile.std
 delete mode 100644 extern/libpng/include/contrib/pngminus/makefile.tc3
 delete mode 100644 extern/libpng/include/contrib/pngminus/makevms.com
 delete mode 100644 extern/libpng/include/contrib/pngminus/png2pnm.bat
 delete mode 100644 extern/libpng/include/contrib/pngminus/png2pnm.c
 delete mode 100644 extern/libpng/include/contrib/pngminus/png2pnm.sh
 delete mode 100644 extern/libpng/include/contrib/pngminus/pngminus.bat
 delete mode 100644 extern/libpng/include/contrib/pngminus/pngminus.sh
 delete mode 100644 extern/libpng/include/contrib/pngminus/pnm2png.bat
 delete mode 100644 extern/libpng/include/contrib/pngminus/pnm2png.c
 delete mode 100644 extern/libpng/include/contrib/pngminus/pnm2png.sh
 delete mode 100644 extern/libpng/include/contrib/pngsuite/README
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn0g01.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn0g02.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn0g04.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn0g08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn0g16.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn2c08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn2c16.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn3p01.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn3p02.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn3p04.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn3p08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn4a08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn4a16.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn6a08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/basn6a16.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftbbn1g04.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftbbn2c16.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftbbn3p08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftbgn2c16.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftbgn3p08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftbrn2c08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftbwn1g16.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftbwn3p08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftbyn3p08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftp0n1g08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftp0n2c08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftp0n3p08.png
 delete mode 100644 extern/libpng/include/contrib/pngsuite/ftp1n3p08.png
 delete mode 100644 extern/libpng/include/contrib/visupng/PngFile.c
 delete mode 100644 extern/libpng/include/contrib/visupng/PngFile.h
 delete mode 100644 extern/libpng/include/contrib/visupng/README.txt
 delete mode 100644 extern/libpng/include/contrib/visupng/VisualPng.c
 delete mode 100644 extern/libpng/include/contrib/visupng/VisualPng.dsp
 delete mode 100644 extern/libpng/include/contrib/visupng/VisualPng.dsw
 delete mode 100644 extern/libpng/include/contrib/visupng/VisualPng.ico
 delete mode 100644 extern/libpng/include/contrib/visupng/VisualPng.png
 delete mode 100644 extern/libpng/include/contrib/visupng/VisualPng.rc
 delete mode 100644 extern/libpng/include/contrib/visupng/cexcept.h
 delete mode 100644 extern/libpng/include/contrib/visupng/resource.h
 delete mode 100755 extern/libpng/include/depcomp
 delete mode 100644 extern/libpng/include/example.c
 delete mode 100755 extern/libpng/include/libpng-config.in
 delete mode 100644 extern/libpng/include/libpng-manual.txt
 delete mode 100644 extern/libpng/include/libpng.3
 delete mode 100644 extern/libpng/include/libpng.pc.in
 delete mode 100644 extern/libpng/include/libpngpf.3
 delete mode 100755 extern/libpng/include/ltmain.sh
 delete mode 100755 extern/libpng/include/missing
 delete mode 100644 extern/libpng/include/png.5
 delete mode 100644 extern/libpng/include/png.c
 delete mode 100644 extern/libpng/include/png.h
 delete mode 100644 extern/libpng/include/pngbar.jpg
 delete mode 100644 extern/libpng/include/pngbar.png
 delete mode 100644 extern/libpng/include/pngconf.h
 delete mode 100644 extern/libpng/include/pngdebug.h
 delete mode 100644 extern/libpng/include/pngerror.c
 delete mode 100644 extern/libpng/include/pngget.c
 delete mode 100644 extern/libpng/include/pnginfo.h
 delete mode 100644 extern/libpng/include/pnglibconf.h
 delete mode 100644 extern/libpng/include/pngmem.c
 delete mode 100644 extern/libpng/include/pngnow.png
 delete mode 100644 extern/libpng/include/pngpread.c
 delete mode 100644 extern/libpng/include/pngpriv.h
 delete mode 100644 extern/libpng/include/pngread.c
 delete mode 100644 extern/libpng/include/pngrio.c
 delete mode 100644 extern/libpng/include/pngrtran.c
 delete mode 100644 extern/libpng/include/pngrutil.c
 delete mode 100644 extern/libpng/include/pngset.c
 delete mode 100644 extern/libpng/include/pngstruct.h
 delete mode 100644 extern/libpng/include/pngtest.c
 delete mode 100644 extern/libpng/include/pngtest.png
 delete mode 100644 extern/libpng/include/pngtrans.c
 delete mode 100644 extern/libpng/include/pngusr.dfa
 delete mode 100644 extern/libpng/include/pngvalid.c
 delete mode 100644 extern/libpng/include/pngwio.c
 delete mode 100644 extern/libpng/include/pngwrite.c
 delete mode 100644 extern/libpng/include/pngwtran.c
 delete mode 100644 extern/libpng/include/pngwutil.c
 delete mode 100644 extern/libpng/include/projects/owatcom/libpng.tgt
 delete mode 100644 extern/libpng/include/projects/owatcom/libpng.wpj
 delete mode 100644 extern/libpng/include/projects/owatcom/pngconfig.mak
 delete mode 100644 extern/libpng/include/projects/owatcom/pngtest.tgt
 delete mode 100644 extern/libpng/include/projects/owatcom/pngvalid.tgt
 delete mode 100644 extern/libpng/include/projects/visualc71/PRJ0041.mak
 delete mode 100644 extern/libpng/include/projects/visualc71/README.txt
 delete mode 100644 extern/libpng/include/projects/visualc71/README_zlib.txt
 delete mode 100644 extern/libpng/include/projects/visualc71/libpng.sln
 delete mode 100644 extern/libpng/include/projects/visualc71/libpng.vcproj
 delete mode 100644 extern/libpng/include/projects/visualc71/pngtest.vcproj
 delete mode 100644 extern/libpng/include/projects/visualc71/zlib.vcproj
 delete mode 100644 extern/libpng/include/projects/vstudio/libpng/libpng.vcxproj
 delete mode 100644 extern/libpng/include/projects/vstudio/pnglibconf/pnglibconf.vcxproj
 delete mode 100644 extern/libpng/include/projects/vstudio/pngtest/pngtest.vcxproj
 delete mode 100644 extern/libpng/include/projects/vstudio/pngvalid/pngvalid.vcxproj
 delete mode 100644 extern/libpng/include/projects/vstudio/readme.txt
 delete mode 100644 extern/libpng/include/projects/vstudio/vstudio.sln
 delete mode 100644 extern/libpng/include/projects/vstudio/zlib.props
 delete mode 100644 extern/libpng/include/projects/vstudio/zlib/zlib.vcxproj
 delete mode 100644 extern/libpng/include/scripts/README.txt
 delete mode 100644 extern/libpng/include/scripts/SCOPTIONS.ppc
 delete mode 100755 extern/libpng/include/scripts/checksym.awk
 delete mode 100755 extern/libpng/include/scripts/chkfmt
 delete mode 100644 extern/libpng/include/scripts/def.dfn
 delete mode 100644 extern/libpng/include/scripts/descrip.mms
 delete mode 100755 extern/libpng/include/scripts/libpng-config-body.in
 delete mode 100755 extern/libpng/include/scripts/libpng-config-head.in
 delete mode 100644 extern/libpng/include/scripts/libpng.pc.in
 delete mode 100644 extern/libpng/include/scripts/makefile.32sunu
 delete mode 100644 extern/libpng/include/scripts/makefile.64sunu
 delete mode 100644 extern/libpng/include/scripts/makefile.acorn
 delete mode 100644 extern/libpng/include/scripts/makefile.aix
 delete mode 100644 extern/libpng/include/scripts/makefile.amiga
 delete mode 100644 extern/libpng/include/scripts/makefile.atari
 delete mode 100644 extern/libpng/include/scripts/makefile.bc32
 delete mode 100644 extern/libpng/include/scripts/makefile.beos
 delete mode 100644 extern/libpng/include/scripts/makefile.bor
 delete mode 100644 extern/libpng/include/scripts/makefile.cegcc
 delete mode 100644 extern/libpng/include/scripts/makefile.darwin
 delete mode 100644 extern/libpng/include/scripts/makefile.dec
 delete mode 100644 extern/libpng/include/scripts/makefile.dj2
 delete mode 100644 extern/libpng/include/scripts/makefile.elf
 delete mode 100644 extern/libpng/include/scripts/makefile.freebsd
 delete mode 100644 extern/libpng/include/scripts/makefile.gcc
 delete mode 100644 extern/libpng/include/scripts/makefile.hp64
 delete mode 100644 extern/libpng/include/scripts/makefile.hpgcc
 delete mode 100644 extern/libpng/include/scripts/makefile.hpux
 delete mode 100644 extern/libpng/include/scripts/makefile.ibmc
 delete mode 100644 extern/libpng/include/scripts/makefile.intel
 delete mode 100644 extern/libpng/include/scripts/makefile.knr
 delete mode 100644 extern/libpng/include/scripts/makefile.linux
 delete mode 100644 extern/libpng/include/scripts/makefile.mips
 delete mode 100644 extern/libpng/include/scripts/makefile.msc
 delete mode 100644 extern/libpng/include/scripts/makefile.ne12bsd
 delete mode 100644 extern/libpng/include/scripts/makefile.netbsd
 delete mode 100644 extern/libpng/include/scripts/makefile.openbsd
 delete mode 100644 extern/libpng/include/scripts/makefile.sco
 delete mode 100644 extern/libpng/include/scripts/makefile.sggcc
 delete mode 100644 extern/libpng/include/scripts/makefile.sgi
 delete mode 100644 extern/libpng/include/scripts/makefile.so9
 delete mode 100644 extern/libpng/include/scripts/makefile.solaris
 delete mode 100644 extern/libpng/include/scripts/makefile.solaris-x86
 delete mode 100644 extern/libpng/include/scripts/makefile.std
 delete mode 100644 extern/libpng/include/scripts/makefile.sunos
 delete mode 100644 extern/libpng/include/scripts/makefile.tc3
 delete mode 100644 extern/libpng/include/scripts/makefile.vcwin32
 delete mode 100644 extern/libpng/include/scripts/makevms.com
 delete mode 100755 extern/libpng/include/scripts/options.awk
 delete mode 100644 extern/libpng/include/scripts/pnglibconf.dfa
 delete mode 100644 extern/libpng/include/scripts/pnglibconf.h.prebuilt
 delete mode 100755 extern/libpng/include/scripts/pnglibconf.mak
 delete mode 100644 extern/libpng/include/scripts/pngwin.rc
 delete mode 100644 extern/libpng/include/scripts/smakefile.ppc
 delete mode 100644 extern/libpng/include/scripts/sym.dfn
 delete mode 100644 extern/libpng/include/scripts/symbols.def
 delete mode 100644 extern/libpng/include/scripts/symbols.dfn
 delete mode 100644 extern/libpng/include/scripts/vers.dfn
 delete mode 100755 extern/libpng/include/test-pngtest.sh
 delete mode 100755 extern/libpng/include/test-pngvalid-full.sh
 delete mode 100755 extern/libpng/include/test-pngvalid-simple.sh

diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000000..19358079f0
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "libpng"]
+	path = extern/libpng
+	url = https://git.code.sf.net/p/libpng/code
diff --git a/extern/libpng b/extern/libpng
new file mode 160000
index 0000000000..5944b94730
--- /dev/null
+++ b/extern/libpng
@@ -0,0 +1 @@
+Subproject commit 5944b9473083c5d03c4600ac5d1675394598e41c
diff --git a/extern/libpng/include/ANNOUNCE b/extern/libpng/include/ANNOUNCE
deleted file mode 100644
index dbc2ed1730..0000000000
--- a/extern/libpng/include/ANNOUNCE
+++ /dev/null
@@ -1,64 +0,0 @@
-
-Libpng 1.5.10 - March 29, 2012
-
-This is a public release of libpng, intended for use in production codes.
-
-Files available for download:
-
-Source files with LF line endings (for Unix/Linux) and with a
-"configure" script
-
-   libpng-1.5.10.tar.xz (LZMA-compressed, recommended)
-   libpng-1.5.10.tar.gz
-   libpng-1.5.10.tar.bz2
-
-Source files with CRLF line endings (for Windows), without the
-"configure" script
-
-   lpng1510.7z  (LZMA-compressed, recommended)
-   lpng1510.zip
-
-Other information:
-
-   libpng-1.5.10-README.txt
-   libpng-1.5.10-LICENSE.txt
-
-Changes since the last public release (1.5.9):
-
-  Removed two useless #ifdef directives from pngread.c and one from pngrutil.c
-  Always put the CMAKE_LIBRARY in "lib" (removed special WIN32 case).
-  Removed empty vstudio/pngstest directory (Clifford Yapp).
-  Eliminated redundant png_push_read_tEXt|zTXt|iTXt|unknown code from
-    pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
-    now that png_ptr->buffer is inaccessible to applications, the special
-    handling is no longer useful.
-  Fixed bug with png_handle_hIST with odd chunk length (Frank Busse).
-  Added PNG_SAFE_LIMITS feature to pnglibconf.dfa and code in pngconf.h
-    to reset the user limits to safe ones if PNG_SAFE_LIMITS is defined.
-    To enable, use "CPPFLAGS=-DPNG_SAFE_LIMITS_SUPPORTED" on the configure
-    command or put "#define PNG_SAFE_LIMITS_SUPPORTED" in pnglibconf.h.
-  Revised the SAFE_LIMITS feature to be the same as the feature in libpng16.
-  Added information about the new limits in the manual.
-  Updated Makefile.in
-  Removed unused "current_text" members of png_struct and the png_free()
-    of png_ptr->current_text from pngread.c
-  Fixed PNG_LIBPNG_BUILD_BASE_TYPE definition.
-  Fixed CMF optimization of non-IDAT compressed chunks, which was added at
-    libpng-1.5.4.  It sometimes produced too small of a window.
-  Reject all iCCP chunks after the first, even if the first one is invalid.
-  Added palette-index checking. Issue a png_benign_error() if an invalid
-    index is found.
-  Revised example.c to put text strings in a temporary character array
-    instead of directly assigning string constants to png_textp members.
-    This avoids compiler warnings when -Wwrite-strings is enabled.
-  Prevent PNG_EXPAND+PNG_SHIFT doing the shift twice.
-  Revised png_set_text_2() to avoid potential memory corruption (fixes
-    CVE-2011-3048).
-
-Send comments/corrections/commendations to png-mng-implement at lists.sf.net
-(subscription required; visit
-https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe)
-or to glennrp at users.sourceforge.net
-
-Glenn R-P
diff --git a/extern/libpng/include/CHANGES b/extern/libpng/include/CHANGES
deleted file mode 100644
index 70af8273e7..0000000000
--- a/extern/libpng/include/CHANGES
+++ /dev/null
@@ -1,3864 +0,0 @@
-#if 0
-CHANGES - changes for libpng
-
-Version 0.2
-  added reader into png.h
-  fixed small problems in stub file
-
-Version 0.3
-  added pull reader
-  split up pngwrite.c to several files
-  added pnglib.txt
-  added example.c
-  cleaned up writer, adding a few new transformations
-  fixed some bugs in writer
-  interfaced with zlib 0.5
-  added K&R support
-  added check for 64 KB blocks for 16-bit machines
-
-Version 0.4
-  cleaned up code and commented code
-  simplified time handling into png_time
-  created png_color_16 and png_color_8 to handle color needs
-  cleaned up color type defines
-  fixed various bugs
-  made various names more consistent
-  interfaced with zlib 0.71
-  cleaned up zTXt reader and writer (using zlib's Reset functions)
-  split transformations into pngrtran.c and pngwtran.c
-
-Version 0.5
-  interfaced with zlib 0.8
-  fixed many reading and writing bugs
-  saved using 3 spaces instead of tabs
-
-Version 0.6
-  added png_large_malloc() and png_large_free()
-  added png_size_t
-  cleaned up some compiler warnings
-  added png_start_read_image()
-
-Version 0.7
-  cleaned up lots of bugs
-  finished dithering and other stuff
-  added test program
-  changed name from pnglib to libpng
-
-Version 0.71 [June, 1995]
-  changed pngtest.png for zlib 0.93
-  fixed error in libpng.txt and example.c
-
-Version 0.8
-  cleaned up some bugs
-  added png_set_filler()
-  split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
-  added #define's to remove unwanted code
-  moved png_info_init() to png.c
-  added old_size into png_realloc()
-  added functions to manually set filtering and compression info
-  changed compression parameters based on image type
-  optimized filter selection code
-  added version info
-  changed external functions passing floats to doubles (k&r problems?)
-  put all the configurable stuff in pngconf.h
-  enabled png_set_shift to work with paletted images on read
-  added png_read_update_info() - updates info structure with transformations
-
-Version 0.81 [August, 1995]
-  incorporated Tim Wegner's medium model code (thanks, Tim)
-
-Version 0.82 [September, 1995]
-  [unspecified changes]
-
-Version 0.85 [December, 1995]
-  added more medium model code (almost everything's a far)
-  added i/o, error, and memory callback functions
-  fixed some bugs (16-bit, 4-bit interlaced, etc.)
-  added first run progressive reader (barely tested)
-
-Version 0.86 [January, 1996]
-  fixed bugs
-  improved documentation
-
-Version 0.87 [January, 1996]
-  fixed medium model bugs
-  fixed other bugs introduced in 0.85 and 0.86
-  added some minor documentation
-
-Version 0.88 [January, 1996]
-  fixed progressive bugs
-  replaced tabs with spaces
-  cleaned up documentation
-  added callbacks for read/write and warning/error functions
-
-Version 0.89 [July, 1996]
-  Added new initialization API to make libpng work better with shared libs
-    we now have png_create_read_struct(), png_create_write_struct(),
-    png_create_info_struct(), png_destroy_read_struct(), and
-    png_destroy_write_struct() instead of the separate calls to
-    malloc and png_read_init(), png_info_init(), and png_write_init()
-  Changed warning/error callback functions to fix bug - this means you
-    should use the new initialization API if you were using the old
-    png_set_message_fn() calls, and that the old API no longer exists
-    so that people are aware that they need to change their code
-  Changed filter selection API to allow selection of multiple filters
-    since it didn't work in previous versions of libpng anyways
-  Optimized filter selection code
-  Fixed png_set_background() to allow using an arbitrary RGB color for
-    paletted images
-  Fixed gamma and background correction for paletted images, so
-    png_correct_palette is not needed unless you are correcting an
-    external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
-    in pngconf.h) - if nobody uses this, it may disappear in the future.
-  Fixed bug with Borland 64K memory allocation (Alexander Lehmann)
-  Fixed bug in interlace handling (Smarasderagd, I think)
-  Added more error checking for writing and image to reduce invalid files
-  Separated read and write functions so that they won't both be linked
-    into a binary when only reading or writing functionality is used
-  New pngtest image also has interlacing and zTXt
-  Updated documentation to reflect new API
-
-Version 0.90 [January, 1997]
-  Made CRC errors/warnings on critical and ancillary chunks configurable
-  libpng will use the zlib CRC routines by (compile-time) default
-  Changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
-  Added external C++ wrapper statements to png.h (Gilles Dauphin)
-  Allow PNG file to be read when some or all of file signature has already
-    been read from the beginning of the stream.  ****This affects the size
-    of info_struct and invalidates all programs that use a shared libpng****
-  Fixed png_filler() declarations
-  Fixed? background color conversions
-  Fixed order of error function pointers to match documentation
-  Current chunk name is now available in png_struct to reduce the number
-    of nearly identical error messages (will simplify multi-lingual
-    support when available)
-  Try to get ready for unknown-chunk callback functions:
-    - previously read critical chunks are flagged, so the chunk handling
-      routines can determine if the chunk is in the right place
-    - all chunk handling routines have the same prototypes, so we will
-      be able to handle all chunks via a callback mechanism
-  Try to fix Linux "setjmp" buffer size problems
-  Removed png_large_malloc, png_large_free, and png_realloc functions.
-
-Version 0.95 [March, 1997]
-  Fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
-  Fixed bug in PNG file signature compares when start != 0
-  Changed parameter type of png_set_filler(...filler...) from png_byte
-    to png_uint_32
-  Added test for MACOS to ensure that both math.h and fp.h are not #included
-  Added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
-  Added "packswap" transformation, which changes the endianness of
-    packed-pixel bytes (Kevin Bracey)
-  Added "strip_alpha" transformation, which removes the alpha channel of
-    input images without using it (not necessarily a good idea)
-  Added "swap_alpha" transformation, which puts the alpha channel in front
-    of the color bytes instead of after
-  Removed all implicit variable tests which assume NULL == 0 (I think)
-  Changed several variables to "png_size_t" to show 16/32-bit limitations
-  Added new pCAL chunk read/write support
-  Added experimental filter selection weighting (Greg Roelofs)
-  Removed old png_set_rgbx() and png_set_xrgb() functions that have been
-     obsolete for about 2 years now (use png_set_filler() instead)
-  Added macros to read 16- and 32-bit ints directly from buffer, to be
-    used only on those systems that support it (namely PowerPC and 680x0)
-    With some testing, this may become the default for MACOS/PPC systems.
-  Only calculate CRC on data if we are going to use it
-  Added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
-  Added macros for simple libpng debugging output selectable at compile time
-  Removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
-  More description of info_struct in libpng.txt and png.h
-  More instructions in example.c
-  More chunk types tested in pngtest.c
-  Renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
-    png_set_<chunk>.  We now have corresponding png_get_<chunk>
-    functions in pngget.c to get information in info_ptr.  This isolates
-    the application from the internal organization of png_info_struct
-    (good for shared library implementations).
-
-Version 0.96 [May, 1997]
-  Fixed serious bug with < 8bpp images introduced in 0.95
-  Fixed 256-color transparency bug (Greg Roelofs)
-  Fixed up documentation (Greg Roelofs, Laszlo Nyul)
-  Fixed "error" in pngconf.h for Linux setjmp() behavior
-  Fixed DOS medium model support (Tim Wegner)
-  Fixed png_check_keyword() for case with error in static string text
-  Added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
-  Added typecasts to quiet compiler errors
-  Added more debugging info
-
-Version 0.97 [January, 1998]
-  Removed PNG_USE_OWN_CRC capability
-  Relocated png_set_crc_action from pngrutil.c to pngrtran.c
-  Fixed typecasts of "new_key", etc. (Andreas Dilger)
-  Added RFC 1152 [sic] date support
-  Fixed bug in gamma handling of 4-bit grayscale
-  Added 2-bit grayscale gamma handling (Glenn R-P)
-  Added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
-  Minor corrections in libpng.txt
-  Added simple sRGB support (Glenn R-P)
-  Easier conditional compiling, e.g.,
-    define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
-    all configurable options can be selected from command-line instead
-    of having to edit pngconf.h (Glenn R-P)
-  Fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
-  Added more conditions for png_do_background, to avoid changing
-    black pixels to background when a background is supplied and
-    no pixels are transparent
-  Repaired PNG_NO_STDIO behavior
-  Tested NODIV support and made it default behavior (Greg Roelofs)
-  Added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
-  Regularized version numbering scheme and bumped shared-library major
-    version number to 2 to avoid problems with libpng 0.89 apps
-    (Greg Roelofs)
-
-Version 0.98 [January, 1998]
-  Cleaned up some typos in libpng.txt and in code documentation
-  Fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
-  Cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
-  Changed recommendation about file_gamma for PC images to .51 from .45,
-    in example.c and libpng.txt, added comments to distinguish between
-    screen_gamma, viewing_gamma, and display_gamma.
-  Changed all references to RFC1152 to read RFC1123 and changed the
-    PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
-  Added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
-  Changed srgb_intent from png_byte to int to avoid compiler bugs
-
-Version 0.99 [January 30, 1998]
-  Free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
-  Fixed a longstanding "packswap" bug in pngtrans.c
-  Fixed some inconsistencies in pngconf.h that prevented compiling with
-    PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
-  Fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
-  Changed recommendation about file_gamma for PC images to .50 from .51 in
-    example.c and libpng.txt, and changed file_gamma for sRGB images to .45
-  Added a number of functions to access information from the png structure
-    png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
-  Added TARGET_MACOS similar to zlib-1.0.8
-  Define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
-  Added type casting to all png_malloc() function calls
-
-Version 0.99a [January 31, 1998]
-  Added type casts and parentheses to all returns that return a value.(Tim W.)
-
-Version 0.99b [February 4, 1998]
-  Added type cast png_uint_32 on malloc function calls where needed.
-  Changed type of num_hist from png_uint_32 to int (same as num_palette).
-  Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
-  Renamed makefile.elf to makefile.lnx.
-
-Version 0.99c [February 7, 1998]
-  More type casting.  Removed erroneous overflow test in pngmem.c.
-  Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
-  Added UNIX manual pages libpng.3 (incorporating libpng.txt) and  png.5.
-
-Version 0.99d [February 11, 1998]
-  Renamed "far_to_near()" "png_far_to_near()"
-  Revised libpng.3
-  Version 99c "buffered" operations didn't work as intended.  Replaced them
-    with png_memcpy_check() and png_memset_check().
-  Added many "if (png_ptr == NULL) return" to quell compiler warnings about
-    unused png_ptr, mostly in pngget.c and pngset.c.
-  Check for overlength tRNS chunk present when indexed-color PLTE is read.
-  Cleaned up spelling errors in libpng.3/libpng.txt
-  Corrected a problem with png_get_tRNS() which returned undefined trans array
-
-Version 0.99e [February 28, 1998]
-  Corrected png_get_tRNS() again.
-  Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
-  Touched up example.c to make more of it compileable, although the entire
-    file still can't be compiled (Willem van Schaik)
-  Fixed a bug in png_do_shift() (Bryan Tsai)
-  Added a space in png.h prototype for png_write_chunk_start()
-  Replaced pngtest.png with one created with zlib 1.1.1
-  Changed pngtest to report PASS even when file size is different (Jean-loup G.)
-  Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
-
-Version 0.99f [March 5, 1998]
-  Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
-  Moved makefiles into a "scripts" directory, and added INSTALL instruction file
-  Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
-  Added pointers to "note on libpng versions" in makefile.lnx and README
-  Added row callback feature when reading and writing nonprogressive rows
-    and added a test of this feature in pngtest.c
-  Added user transform callbacks, with test of the feature in pngtest.c
-
-Version 0.99g [March 6, 1998, morning]
-  Minor changes to pngtest.c to suppress compiler warnings.
-  Removed "beta" language from documentation.
-
-Version 0.99h [March 6, 1998, evening]
-  Minor changes to previous minor changes to pngtest.c
-  Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
-    and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
-  Added user transform capability
-
-Version 1.00 [March 7, 1998]
-  Changed several typedefs in pngrutil.c
-  Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
-  Replaced "while(1)" with "for(;;)"
-  Added PNGARG() to prototypes in pngtest.c and removed some prototypes
-  Updated some of the makefiles (Tom Lane)
-  Changed some typedefs (s_start, etc.) in pngrutil.c
-  Fixed dimensions of "short_months" array in pngwrite.c
-  Replaced ansi2knr.c with the one from jpeg-v6
-
-Version 1.0.0 [March 8, 1998]
-  Changed name from 1.00 to 1.0.0 (Adam Costello)
-  Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
-
-Version 1.0.0a [March 9, 1998]
-  Fixed three bugs in pngrtran.c to make gamma+background handling consistent
-    (Greg Roelofs)
-  Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
-    for major, minor, and bugfix releases.  This is 10001. (Adam Costello,
-    Tom Lane)
-  Make months range from 1-12 in png_convert_to_rfc1123
-
-Version 1.0.0b [March 13, 1998]
-  Quieted compiler complaints about two empty "for" loops in pngrutil.c
-  Minor changes to makefile.s2x
-  Removed #ifdef/#endif around a png_free() in pngread.c
-
-Version 1.0.1 [March 14, 1998]
-  Changed makefile.s2x to reduce security risk of using a relative pathname
-  Fixed some typos in the documentation (Greg).
-  Fixed a problem with value of "channels" returned by png_read_update_info()
-
-Version 1.0.1a [April 21, 1998]
-  Optimized Paeth calculations by replacing abs() function calls with intrinsics
-  plus other loop optimizations. Improves avg decoding speed by about 20%.
-  Commented out i386istic "align" compiler flags in makefile.lnx.
-  Reduced the default warning level in some makefiles, to make them consistent.
-  Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
-  Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
-  Added grayscale and 16-bit capability to png_do_read_filler().
-  Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
-    too large when writing an image with bit_depth < 8 (Bob Dellaca).
-  Corrected some bugs in the experimental weighted filtering heuristics.
-  Moved a misplaced pngrutil code block that truncates tRNS if it has more
-    than num_palette entries -- test was done before num_palette was defined.
-  Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
-  Changed compiler flags in makefile.wat for better optimization
-    (Pawel Mrochen).
-
-Version 1.0.1b [May 2, 1998]
-  Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
-  Relocated the png_composite macros from pngrtran.c to png.h (Greg).
-  Added makefile.sco (contributed by Mike Hopkirk).
-  Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
-  Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
-  More work on the Paeth-filtering, achieving imperceptible speedup
-    (A Kleinert).
-  More work on loop optimization which may help when compiled with C++
-    compilers.
-  Added warnings when people try to use transforms they've defined out.
-  Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
-  Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
-
-Version 1.0.1c [May 11, 1998]
-  Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
-    filler bytes should have been 0xff instead of 0xf.
-  Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
-  Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
-    out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
-  Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
-    for consistency, in pngconf.h
-  Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
-    to remove unwanted capabilities via the compile line
-  Made some corrections to grammar (which, it's) in documentation (Greg).
-  Corrected example.c, use of row_pointers in png_write_image().
-
-Version 1.0.1d [May 24, 1998]
-  Corrected several statements that used side effects illegally in pngrutil.c
-    and pngtrans.c, that were introduced in version 1.0.1b
-  Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
-  More corrections to example.c, use of row_pointers in png_write_image()
-    and png_read_rows().
-  Added pngdll.mak and pngdef.pas to scripts directory, contributed by
-    Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
-  Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
-  Changed several loops from count-down to count-up, for consistency.
-
-Version 1.0.1e [June 6, 1998]
-  Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
-    added warnings when people try to set png_read_fn and png_write_fn in
-    the same structure.
-  Added a test such that png_do_gamma will be done when num_trans==0
-    for truecolor images that have defined a background.  This corrects an
-    error that was introduced in libpng-0.90 that can cause gamma processing
-    to be skipped.
-  Added tests in png.h to include "trans" and "trans_values" in structures
-    when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
-  Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
-  Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
-  Added capability for user-provided malloc_fn() and free_fn() functions,
-    and revised pngtest.c to demonstrate their use, replacing the
-    PNGTEST_DEBUG_MEM feature.
-  Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
-
-Version 1.0.2 [June 14, 1998]
-  Fixed two bugs in makefile.bor .
-
-Version 1.0.2a [December 30, 1998]
-  Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
-  Fixed a bug in png_do_filler() that made it fail to write filler bytes in
-    the left-most pixel of each row (Kevin Bracey).
-  Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
-    in pngtest.c (Duncan Simpson).
-  Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
-    even when no tIME chunk was present in the source file.
-  Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
-  Fixed a problem in png_read_push_finish_row(), which would not skip some
-    passes that it should skip, for images that are less than 3 pixels high.
-  Interchanged the order of calls to png_do_swap() and png_do_shift()
-    in pngwtran.c (John Cromer).
-  Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
-  Changed "bad adaptive filter type" from error to warning in pngrutil.c .
-  Fixed a documentation error about default filtering with 8-bit indexed-color.
-  Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
-    (L. Peter Deutsch).
-  Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
-  Added png_get_copyright() and png_get_header_version() functions.
-  Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
-  Added information about debugging in libpng.txt and libpng.3 .
-  Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and
-    makefile.sco.
-  Removed lines after Dynamic Dependencies" in makefile.aco .
-  Revised makefile.dec to make a shared library (Jeremie Petit).
-  Removed trailing blanks from all files.
-
-Version 1.0.2a [January 6, 1999]
-  Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
-  Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
-  Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
-  Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
-    which is obsolete.
-
-Version 1.0.3 [January 14, 1999]
-  Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
-  Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
-
-Version 1.0.3a [August 12, 1999]
-  Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
-     if an attempt is made to read an interlaced image when it's not supported.
-  Added check if png_ptr->trans is defined before freeing it in pngread.c
-  Modified the Y2K statement to include versions back to version 0.71
-  Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
-  Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
-  Replaced leading blanks with tab characters in makefile.hux
-  Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
-  Changed (float)red and (float)green to (double)red, (double)green
-     in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
-  Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
-  Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
-  Updated documentation to refer to the PNG-1.2 specification.
-  Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
-    in makefile.knr, INSTALL, and README (L. Peter Deutsch)
-  Fixed bugs in calculation of the length of rowbytes when adding alpha
-    channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
-  Added function png_set_user_transform_info() to store user_transform_ptr,
-    user_depth, and user_channels into the png_struct, and a function
-    png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
-  Added function png_set_empty_plte_permitted() to make libpng useable
-    in MNG applications.
-  Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
-  Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
-    consistent with PNG-1.2, and allow variance of 500 before complaining.
-  Added assembler code contributed by Intel in file pngvcrd.c and modified
-    makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation,
-    Gilles Vollant)
-  Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
-  Added some aliases for png_set_expand() in pngrtran.c, namely
-    png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
-    (Greg Roelofs, in "PNG: The Definitive Guide").
-  Added makefile.beo for BEOS on X86, contributed by Sander Stok.
-
-Version 1.0.3b [August 26, 1999]
-  Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
-  Changed leading blanks to tabs in all makefiles.
-  Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
-  Made alternate versions of  png_set_expand() in pngrtran.c, namely
-    png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
-    (Greg Roelofs, in "PNG: The Definitive Guide").  Deleted the 1.0.3a aliases.
-  Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
-  Revised calculation of num_blocks in pngmem.c to avoid a potentially
-    negative shift distance, whose results are undefined in the C language.
-  Added a check in pngset.c to prevent writing multiple tIME chunks.
-  Added a check in pngwrite.c to detect invalid small window_bits sizes.
-
-Version 1.0.3d [September 4, 1999]
-  Fixed type casting of igamma in pngrutil.c
-  Added new png_expand functions to scripts/pngdef.pas and pngos2.def
-  Added a demo read_user_transform_fn that examines the row filters in pngtest.c
-
-Version 1.0.4 [September 24, 1999]
-  Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
-  Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
-  Made several minor corrections to pngtest.c
-  Renamed the makefiles with longer but more user friendly extensions.
-  Copied the PNG copyright and license to a separate LICENSE file.
-  Revised documentation, png.h, and example.c to remove reference to
-    "viewing_gamma" which no longer appears in the PNG specification.
-  Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
-  Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
-  Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
-    assembler code) and makefile.vcwin32 (doesn't).
-  Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
-  Added a copy of pngnow.png to the distribution.
-
-Version 1.0.4a [September 25, 1999]
-  Increase max_pixel_depth in pngrutil.c if a user transform needs it.
-  Changed several division operations to right-shifts in pngvcrd.c
-
-Version 1.0.4b [September 30, 1999]
-  Added parentheses in line 3732 of pngvcrd.c
-  Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
-
-Version 1.0.4c [October 1, 1999]
-  Added a "png_check_version" function in png.c and pngtest.c that will generate
-    a helpful compiler error if an old png.h is found in the search path.
-  Changed type of png_user_transform_depth|channels from int to png_byte.
-
-Version 1.0.4d [October 6, 1999]
-  Changed 0.45 to 0.45455 in png_set_sRGB()
-  Removed unused PLTE entries from pngnow.png
-  Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
-
-Version 1.0.4e [October 10, 1999]
-  Fixed sign error in pngvcrd.c (Greg Roelofs)
-  Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
-
-Version 1.0.4f [October 15, 1999]
-  Surrounded example.c code with #if 0 .. #endif to prevent people from
-    inadvertently trying to compile it.
-  Changed png_get_header_version() from a function to a macro in png.h
-  Added type casting mostly in pngrtran.c and pngwtran.c
-  Removed some pointless "ptr = NULL" in pngmem.c
-  Added a "contrib" directory containing the source code from Greg's book.
-
-Version 1.0.5 [October 15, 1999]
-  Minor editing of the INSTALL and README files.
-
-Version 1.0.5a [October 23, 1999]
-  Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
-  Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
-  Further optimization and bugfix of pngvcrd.c
-  Revised pngset.c so that it does not allocate or free memory in the user's
-    text_ptr structure.  Instead, it makes its own copy.
-  Created separate write_end_info_struct in pngtest.c for a more severe test.
-  Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
-
-Version 1.0.5b [November 23, 1999]
-  Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
-    PNG_FLAG_WROTE_tIME from flags to mode.
-  Added png_write_info_before_PLTE() function.
-  Fixed some typecasting in contrib/gregbook/*.c
-  Updated scripts/makevms.com and added makevms.com to contrib/gregbook
-    and contrib/pngminus (Martin Zinser)
-
-Version 1.0.5c [November 26, 1999]
-  Moved png_get_header_version from png.h to png.c, to accommodate ansi2knr.
-  Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
-    accommodate making DLL's: Moved usr_png_ver from global variable to function
-    png_get_header_ver() in png.c.  Moved png_sig to png_sig_bytes in png.c and
-    eliminated use of png_sig in pngwutil.c.  Moved the various png_CHNK arrays
-    into pngtypes.h.  Eliminated use of global png_pass arrays.  Declared the
-    png_CHNK and png_pass arrays to be "const".  Made the global arrays
-    available to applications (although none are used in libpng itself) when
-    PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
-  Removed some extraneous "-I" from contrib/pngminus/makefile.std
-  Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
-  Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
-
-Version 1.0.5d [November 29, 1999]
-  Add type cast (png_const_charp) two places in png.c
-  Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
-  Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
-    to applications a macro "PNG_USE_LOCAL_ARRAYS".
-  comment out (with #ifdef) all the new declarations when
-    PNG_USE_GLOBAL_ARRAYS is defined.
-  Added PNG_EXPORT_VAR macro to accommodate making DLL's.
-
-Version 1.0.5e [November 30, 1999]
-  Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
-    structure; refactored the inflate/deflate support to make adding new chunks
-    with trailing compressed parts easier in the future, and added new functions
-    png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
-    png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
-  NOTE: Applications that write text chunks MUST define png_text->lang
-    before calling png_set_text(). It must be set to NULL if you want to
-    write tEXt or zTXt chunks.  If you want your application to be able to
-    run with older versions of libpng, use
-
-      #ifdef PNG_iTXt_SUPPORTED
-         png_text[i].lang = NULL;
-      #endif
-
-  Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
-    offsets (Eric S. Raymond).
-  Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
-    PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
-    macros, leaving the separate macros also available.
-  Removed comments on #endifs at the end of many short, non-nested #if-blocks.
-
-Version 1.0.5f [December 6, 1999]
-  Changed makefile.solaris to issue a warning about potential problems when
-    the ucb "ld" is in the path ahead of the ccs "ld".
-  Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
-  Added sCAL chunk support (Eric S. Raymond).
-
-Version 1.0.5g [December 7, 1999]
-  Fixed "png_free_spallettes" typo in png.h
-  Added code to handle new chunks in pngpread.c
-  Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
-  Added "translated_key" to png_text structure and png_write_iTXt().
-  Added code in pngwrite.c to work around a newly discovered zlib bug.
-
-Version 1.0.5h [December 10, 1999]
-  NOTE: regarding the note for version 1.0.5e, the following must also
-    be included in your code:
-        png_text[i].translated_key = NULL;
-  Unknown chunk handling is now supported.
-  Option to eliminate all floating point support was added.  Some new
-    fixed-point functions such as png_set_gAMA_fixed() were added.
-  Expanded tabs and removed trailing blanks in source files.
-
-Version 1.0.5i [December 13, 1999]
-  Added some type casts to silence compiler warnings.
-  Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
-  Removed leading blanks from a #define in pngvcrd.c
-  Added some parameters to the new png_set_keep_unknown_chunks() function.
-  Added a test for up->location != 0 in the first instance of writing
-    unknown chunks in pngwrite.c
-  Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
-    prevent recursion.
-  Added png_free_hIST() function.
-  Various patches to fix bugs in the sCAL and integer cHRM processing,
-    and to add some convenience macros for use with sCAL.
-
-Version 1.0.5j [December 21, 1999]
-  Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
-    around buggy compilers.
-  Added new type "png_fixed_point" for integers that hold float*100000 values
-  Restored backward compatibility of tEXt/zTXt chunk processing:
-    Restored the first four members of png_text to the same order as v.1.0.5d.
-    Added members "lang_key" and "itxt_length" to png_text struct.  Set
-    text_length=0 when "text" contains iTXt data.  Use the "compression"
-    member to distinguish among tEXt/zTXt/iTXt types.  Added
-    PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
-    The "Note" above, about backward incompatibility of libpng-1.0.5e, no
-    longer applies.
-  Fixed png_read|write_iTXt() to read|write parameters in the right order,
-    and to write the iTXt chunk after IDAT if it appears in the end_ptr.
-  Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
-  Reversed the order of trying to write floating-point and fixed-point gAMA.
-
-Version 1.0.5k [December 27, 1999]
-  Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
-  Added png_handle_as_unknown() function (Glenn)
-  Added png_free_chunk_list() function and chunk_list and num_chunk_list members
-    of png_ptr.
-  Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
-  Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
-    about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
-  Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
-  Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
-  Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
-
-Version 1.0.5l [January 1, 2000]
-  Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
-    for setting a callback function to handle unknown chunks and for
-    retrieving the associated user pointer (Glenn).
-
-Version 1.0.5m [January 7, 2000]
-  Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
-
-Version 1.0.5n [January 9, 2000]
-  Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
-    own memory for info_ptr->palette.  This makes it safe for the calling
-    application to free its copy of the palette any time after it calls
-    png_set_PLTE().
-
-Version 1.0.5o [January 20, 2000]
-  Cosmetic changes only (removed some trailing blanks and TABs)
-
-Version 1.0.5p [January 31, 2000]
-  Renamed pngdll.mak to makefile.bd32
-  Cosmetic changes in pngtest.c
-
-Version 1.0.5q [February 5, 2000]
-  Relocated the makefile.solaris warning about PATH problems.
-  Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
-  Revised makefile.gcmmx
-  Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
-
-Version 1.0.5r [February 7, 2000]
-  Removed superfluous prototype for png_get_itxt from png.h
-  Fixed a bug in pngrtran.c that improperly expanded the background color.
-  Return *num_text=0 from png_get_text() when appropriate, and fix documentation
-    of png_get_text() in libpng.txt/libpng.3.
-
-Version 1.0.5s [February 18, 2000]
-  Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
-    new error handler that's planned for the next libpng release, and changed
-    example.c, pngtest.c, and contrib programs to use this macro.
-  Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
-  Fixed a bug in png_read_png() that caused it to fail to expand some images
-    that it should have expanded.
-  Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
-    in pngget.c
-  Changed the allocation of palette, history, and trans arrays back to
-    the version 1.0.5 method (linking instead of copying) which restores
-    backward compatibility with version 1.0.5.  Added some remarks about
-    that in example.c.  Added "free_me" member to info_ptr and png_ptr
-    and added png_free_data() function.
-  Updated makefile.linux and makefile.gccmmx to make directories conditionally.
-  Made cosmetic changes to pngasmrd.h
-  Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
-  Modified png_read_png() to allocate info_ptr->row_pointers only if it
-    hasn't already been allocated.
-
-Version 1.0.5t [March 4, 2000]
-  Changed png_jmp_env() migration aiding macro to png_jmpbuf().
-  Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
-  Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
-    PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
-  Files in contrib/gregbook were revised to use png_jmpbuf() and to select
-    a 24-bit visual if one is available, and to allow abbreviated options.
-  Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
-  Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
-
-Version 1.0.5u [March 5, 2000]
-  Simplified the code that detects old png.h in png.c and pngtest.c
-  Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
-  Increased precision of rgb_to_gray calculations from 8 to 15 bits and
-    added png_set_rgb_to_gray_fixed() function.
-  Added makefile.bc32 (32-bit Borland C++, C mode)
-
-Version 1.0.5v [March 11, 2000]
-  Added some parentheses to the png_jmpbuf macro definition.
-  Updated references to the zlib home page, which has moved to freesoftware.com.
-  Corrected bugs in documentation regarding png_read_row() and png_write_row().
-  Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
-  Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
-    revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
-
-Version 1.0.6 [March 20, 2000]
-  Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
-  Added makefile.sggcc (SGI IRIX with gcc)
-
-Version 1.0.6d [April 7, 2000]
-  Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
-  Added data_length parameter to png_decompress_chunk() function
-  Revised documentation to remove reference to abandoned png_free_chnk functions
-  Fixed an error in png_rgb_to_gray_fixed()
-  Revised example.c, usage of png_destroy_write_struct().
-  Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
-  Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c
-  Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
-
-Version 1.0.6e [April 9, 2000]
-  Added png_data_freer() function.
-  In the code that checks for over-length tRNS chunks, added check of
-    info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
-  Minor revisions of libpng.txt/libpng.3.
-  Check for existing data and free it if the free_me flag is set, in png_set_*()
-    and png_handle_*().
-  Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
-    is defined.
-  Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
-    and mentioned the purposes of the two macros in libpng.txt/libpng.3.
-
-Version 1.0.6f [April 14, 2000]
-  Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
-  Add checks in png_set_text() for NULL members of the input text structure.
-  Revised libpng.txt/libpng.3.
-  Removed superfluous prototype for png_set_iTXt from png.h
-  Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
-  Changed several png_errors about malformed ancillary chunks to png_warnings.
-
-Version 1.0.6g [April 24, 2000]
-  Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
-  Relocated paragraph about png_set_background() in libpng.3/libpng.txt
-    and other revisions (Matthias Benckmann)
-  Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
-    png_ptr members to restore binary compatibility with libpng-1.0.5
-    (breaks compatibility with libpng-1.0.6).
-
-Version 1.0.6h [April 24, 2000]
-  Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
-    libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
-    This is a temporary change for test purposes.
-
-Version 1.0.6i [May 2, 2000]
-  Rearranged some members at the end of png_info and png_struct, to put
-    unknown_chunks_num and free_me within the original size of the png_structs
-    and free_me, png_read_user_fn, and png_free_fn within the original png_info,
-    because some old applications allocate the structs directly instead of
-    using png_create_*().
-  Added documentation of user memory functions in libpng.txt/libpng.3
-  Modified png_read_png so that it will use user_allocated row_pointers
-    if present, unless free_me directs that it be freed, and added description
-    of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
-  Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
-    1.00) members of png_struct and png_info, to regain binary compatibility
-    when you define this macro.  Capabilities lost in this event
-    are user transforms (new in version 1.0.0),the user transform pointer
-    (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
-    the high-level interface, and unknown chunks support (all new in 1.0.6).
-    This was necessary because of old applications that allocate the structs
-    directly as authors were instructed to do in libpng-0.88 and earlier,
-    instead of using png_create_*().
-  Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
-    can be used to detect codes that directly allocate the structs, and
-    code to check these modes in png_read_init() and png_write_init() and
-    generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
-    was not defined.
-  Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
-
-Version 1.0.6j [May 3, 2000]
-  Overloaded png_read_init() and png_write_init() with macros that convert
-    calls to png_read_init_2() or png_write_init_2() that check the version
-    and structure sizes.
-
-Version 1.0.7beta11 [May 7, 2000]
-  Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
-    which are no longer used.
-  Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
-    defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXT_SUPPORTED
-    is defined.
-  Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
-    overrun when old applications fill the info_ptr->text structure directly.
-  Added PNGAPI macro, and added it to the definitions of all exported functions.
-  Relocated version macro definitions ahead of the includes of zlib.h and
-    pngconf.h in png.h.
-
-Version 1.0.7beta12 [May 12, 2000]
-  Revised pngset.c to avoid a problem with expanding the png_debug macro.
-  Deleted some extraneous defines from pngconf.h
-  Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
-  Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
-  Added png_access_version_number() function.
-  Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
-  Expanded libpng.3/libpng.txt information about png_data_freer().
-
-Version 1.0.7beta14 [May 17, 2000] (beta13 was not published)
-  Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as
-    warnings instead of errors, as pngrutil.c does.
-  Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png()
-    will actually write IDATs.
-  Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32.
-  Make png_free_data() ignore its final parameter except when freeing data
-    that can have multiple instances (text, sPLT, unknowns).
-  Fixed a new bug in png_set_rows().
-  Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5.
-  Added png_set_invalid() function.
-  Fixed incorrect illustrations of png_destroy_write_struct() in example.c.
-
-Version 1.0.7beta15 [May 30, 2000]
-  Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce
-    fewer error messages.
-  Rearranged checks for Z_OK to check the most likely path first in pngpread.c
-    and pngwutil.c.
-  Added checks in pngtest.c for png_create_*() returning NULL, and mentioned
-    in libpng.txt/libpng.3 the need for applications to check this.
-  Changed names of png_default_*() functions in pngtest to pngtest_*().
-  Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32.
-  Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c
-  Set each pointer to NULL after freeing it in png_free_data().
-  Worked around a problem in pngconf.h; AIX's strings.h defines an "index"
-    macro that conflicts with libpng's png_color_16.index. (Dimitri
-    Papadapoulos)
-  Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux).
-
-Version 1.0.7beta16 [June 4, 2000]
-  Revised the workaround of AIX string.h "index" bug.
-  Added a check for overlength PLTE chunk in pngrutil.c.
-  Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer
-    indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler.
-  Added a warning in png_decompress_chunk() when it runs out of data, e.g.
-    when it tries to read an erroneous PhotoShop iCCP chunk.
-  Added PNG_USE_DLL macro.
-  Revised the copyright/disclaimer/license notice.
-  Added contrib/msvctest directory
-
-Version 1.0.7rc1 [June 9, 2000]
-  Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA  (0x0400 not 0x0200)
-  Added contrib/visupng directory (Willem van Schaik)
-
-Version 1.0.7beta18 [June 23, 2000]
-  Revised PNGAPI definition, and pngvcrd.c to work with __GCC__
-    and do not redefine PNGAPI if it is passed in via a compiler directive.
-  Revised visupng/PngFile.c to remove returns from within the Try block.
-  Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros.
-  Updated contrib/visupng/cexcept.h to version 1.0.0.
-  Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks.
-
-Version 1.0.7rc2 [June 28, 2000]
-  Updated license to include disclaimers required by UCITA.
-  Fixed "DJBPP" typo in pnggccrd.c introduced in beta18.
-
-Version 1.0.7 [July 1, 2000]
-  Revised the definition of "trans_values" in libpng.3/libpng.txt
-
-Version 1.0.8beta1 [July 8, 2000]
-  Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
-  Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
-     pngwutil.c.
-  Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
-  Removed unused "#include <assert.h>" from png.c
-  Added WindowsCE support.
-  Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment.
-
-Version 1.0.8beta2 [July 10, 2000]
-  Added project files to the wince directory and made further revisions
-     of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
-
-Version 1.0.8beta3 [July 11, 2000]
-  Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
-     for indexed-color input files to avoid potential double-freeing trans array
-     under some unusual conditions; problem was introduced in version 1.0.6f.
-  Further revisions to pngtest.c and files in the wince subdirectory.
-
-Version 1.0.8beta4 [July 14, 2000]
-  Added the files pngbar.png and pngbar.jpg to the distribution.
-  Added makefile.cygwin, and cygwin support in pngconf.h
-  Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory)
-
-Version 1.0.8rc1 [July 16, 2000]
-  Revised png_debug() macros and statements to eliminate compiler warnings.
-
-Version 1.0.8 [July 24, 2000]
-  Added png_flush() in pngwrite.c, after png_write_IEND().
-  Updated makefile.hpux to build a shared library.
-
-Version 1.0.9beta1 [November 10, 2000]
-  Fixed typo in scripts/makefile.hpux
-  Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
-  Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
-  Changed "cdrom.com" in documentation to "libpng.org"
-  Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
-  Changed type of "params" from voidp to png_voidp in png_read|write_png().
-  Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h.
-  Revised the 3 instances of WRITEFILE in pngtest.c.
-  Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory.
-  Updated png.rc in dll/msvc project
-  Revised makefile.dec to define and use LIBPATH and INCPATH
-  Increased size of global png_libpng_ver[] array from 12 to 18 chars.
-  Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const.
-  Removed duplicate png_crc_finish() from png_handle_bKGD() function.
-  Added a warning when application calls png_read_update_info() multiple times.
-  Revised makefile.cygwin
-  Fixed bugs in iCCP support in pngrutil.c and pngwutil.c.
-  Replaced png_set_empty_plte_permitted() with png_permit_mng_features().
-
-Version 1.0.9beta2 [November 19, 2000]
-  Renamed the "dll" subdirectory "projects".
-  Added borland project files to "projects" subdirectory.
-  Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate.
-  Add error message in png_set_compression_buffer_size() when malloc fails.
-
-Version 1.0.9beta3 [November 23, 2000]
-  Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project.
-  Removed the png_flush() in pngwrite.c that crashes some applications
-    that don't set png_output_flush_fn.
-  Added makefile.macosx and makefile.aix to scripts directory.
-
-Version 1.0.9beta4 [December 1, 2000]
-  Change png_chunk_warning to png_warning in png_check_keyword().
-  Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
-
-Version 1.0.9beta5 [December 15, 2000]
-  Added support for filter method 64 (for PNG datastreams embedded in MNG).
-
-Version 1.0.9beta6 [December 18, 2000]
-  Revised png_set_filter() to accept filter method 64 when appropriate.
-  Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
-    help prevent applications from using MNG features in PNG datastreams.
-  Added png_permit_mng_features() function.
-  Revised libpng.3/libpng.txt.  Changed "filter type" to "filter method".
-
-Version 1.0.9rc1 [December 23, 2000]
-  Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c
-  Fixed error handling of unknown compression type in png_decompress_chunk().
-  In pngconf.h, define __cdecl when _MSC_VER is defined.
-
-Version 1.0.9beta7 [December 28, 2000]
-  Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places.
-  Revised memory management in png_set_hIST and png_handle_hIST in a backward
-    compatible manner.  PLTE and tRNS were revised similarly.
-  Revised the iCCP chunk reader to ignore trailing garbage.
-
-Version 1.0.9beta8 [January 12, 2001]
-  Moved pngasmrd.h into pngconf.h.
-  Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop.
-
-Version 1.0.9beta9 [January 15, 2001]
-  Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to
-    wince and msvc project module definition files.
-  Minor revision of makefile.cygwin.
-  Fixed bug with progressive reading of narrow interlaced images in pngpread.c
-
-Version 1.0.9beta10 [January 16, 2001]
-  Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined.
-  Fixed "png_mmx_supported" typo in project definition files.
-
-Version 1.0.9beta11 [January 19, 2001]
-  Updated makefile.sgi to make shared library.
-  Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED
-    by default, for the benefit of DLL forward compatibility.  These will
-    be re-enabled in version 1.2.0.
-
-Version 1.0.9rc2 [January 22, 2001]
-  Revised cygwin support.
-
-Version 1.0.9 [January 31, 2001]
-  Added check of cygwin's ALL_STATIC in pngconf.h
-  Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
-
-Version 1.0.10beta1 [March 14, 2001]
-  Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
-  Reformatted libpng.3 to eliminate bad line breaks.
-  Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
-  Added prototype for png_mmx_support() near the top of pnggccrd.c
-  Moved some error checking from png_handle_IHDR to png_set_IHDR.
-  Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
-  Revised png_mmx_support() function in pnggccrd.c
-  Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
-  Fixed memory leak in contrib/visupng/PngFile.c
-  Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
-  Added warnings when retrieving or setting gamma=0.
-  Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
-
-Version 1.0.10rc1 [March 23, 2001]
-  Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
-    and png_strlen.
-  Revised png_mmx_supported() function in pnggccrd.c to return proper value.
-  Fixed bug in progressive reading (pngpread.c) with small images (height < 8).
-
-Version 1.0.10 [March 30, 2001]
-  Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
-  Added beos project files (Chris Herborth)
-
-Version 1.0.11beta1 [April 3, 2001]
-  Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
-  Removed a no-longer needed AIX work-around from pngconf.h
-  Changed several "//" single-line comments to C-style in pnggccrd.c
-
-Version 1.0.11beta2 [April 11, 2001]
-  Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
-  Updated scripts/pngos2.def
-
-Version 1.0.11beta3 [April 14, 2001]
-  Added checking the results of many instances of png_malloc() for NULL
-
-Version 1.0.11beta4 [April 20, 2001]
-  Undid the changes from version 1.0.11beta3.  Added a check for NULL return
-    from user's malloc_fn().
-  Removed some useless type casts of the NULL pointer.
-  Added makefile.netbsd
-
-Version 1.0.11 [April 27, 2001]
-  Revised makefile.netbsd
-
-Version 1.0.12beta1 [May 14, 2001]
-  Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
-  Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
-  Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
-  Eliminated the png_error about apps using png_read|write_init().  Instead,
-    libpng will reallocate the png_struct and info_struct if they are too small.
-    This retains future binary compatibility for old applications written for
-    libpng-0.88 and earlier.
-
-Version 1.2.0beta1 [May 6, 2001]
-  Bumped DLLNUM to 2.
-  Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED
-    by default.
-  Added runtime selection of MMX features.
-  Added png_set_strip_error_numbers function and related macros.
-
-Version 1.2.0beta2 [May 7, 2001]
-  Finished merging 1.2.0beta1 with version 1.0.11
-  Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
-
-Version 1.2.0beta3 [May 17, 2001]
-  Enabled user memory function by default.
-  Modified png_create_struct so it passes user mem_ptr to user memory allocator.
-  Increased png_mng_features flag from png_byte to png_uint_32.
-  Bumped shared-library (so-number) and dll-number to 3.
-
-Version 1.2.0beta4 [June 23, 2001]
-  Check for missing profile length field in iCCP chunk and free chunk_data
-     in case of truncated iCCP chunk.
-  Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
-  Bumped dll-number from 2 to 3 in makefile.cygwin
-  Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
-     if user attempts to run it on an 8-bit display.
-  Updated contrib/gregbook
-  Use png_malloc instead of png_zalloc to allocate palette in pngset.c
-  Updated makefile.ibmc
-  Added some typecasts to eliminate gcc 3.0 warnings.  Changed prototypes
-     of png_write_oFFS width and height from png_uint_32 to png_int_32.
-  Updated example.c
-  Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
-
-Version 1.2.0beta5 [August 8, 2001]
-  Revised contrib/gregbook
-  Revised makefile.gcmmx
-  Revised pnggccrd.c to conditionally compile some thread-unsafe code only
-     when PNG_THREAD_UNSAFE_OK is defined.
-  Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
-     value exceeding 2^bit_depth-1
-  Revised makefile.sgi and makefile.sggcc
-  Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
-  Removed restriction that do_invert_mono only operate on 1-bit opaque files
-
-Version 1.2.0 [September 1, 2001]
-  Changed a png_warning() to png_debug() in pnggccrd.c
-  Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC().
-
-Version 1.2.1beta1 [October 19, 2001]
-  Revised makefile.std in contrib/pngminus
-  Include background_1 in png_struct regardless of gamma support.
-  Revised makefile.netbsd and makefile.macosx, added makefile.darwin.
-  Revised example.c to provide more details about using row_callback().
-
-Version 1.2.1beta2 [October 25, 2001]
-  Added type cast to each NULL appearing in a function call, except for
-    WINCE functions.
-  Added makefile.so9.
-
-Version 1.2.1beta3 [October 27, 2001]
-  Removed type casts from all NULLs.
-  Simplified png_create_struct_2().
-
-Version 1.2.1beta4 [November 7, 2001]
-  Revised png_create_info_struct() and png_creat_struct_2().
-  Added error message if png_write_info() was omitted.
-  Type cast NULLs appearing in function calls when _NO_PROTO or
-    PNG_TYPECAST_NULL is defined.
-
-Version 1.2.1rc1 [November 24, 2001]
-  Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL
-    is defined.
-  Changed typecast of "size" argument to png_size_t in pngmem.c calls to
-    the user malloc_fn, to agree with the prototype in png.h
-  Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev)
-  Updated makefile.sgi to recognize LIBPATH and INCPATH.
-  Updated various makefiles so "make clean" does not remove previous major
-    version of the shared library.
-
-Version 1.2.1rc2 [December 4, 2001]
-  Always allocate 256-entry internal palette, hist, and trans arrays, to
-    avoid out-of-bounds memory reference caused by invalid PNG datastreams.
-  Added a check for prefix_length > data_length in iCCP chunk handler.
-
-Version 1.2.1 [December 7, 2001]
-  None.
-
-Version 1.2.2beta1 [February 22, 2002]
-  Fixed a bug with reading the length of iCCP profiles (Larry Reeves).
-  Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate
-    libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h
-  Revised makefile.darwin to remove "-undefined suppress" option.
-  Added checks for gamma and chromaticity values over 21474.83, which exceed
-    the limit for PNG unsigned 32-bit integers when encoded.
-  Revised calls to png_create_read_struct() and png_create_write_struct()
-    for simpler debugging.
-  Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK)
-
-Version 1.2.2beta2 [February 23, 2002]
-  Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths.
-  Check for invalid image dimensions in png_get_IHDR.
-  Added missing "fi;" in the install target of the SGI makefiles.
-  Added install-static to all makefiles that make shared libraries.
-  Always do gamma compensation when image is partially transparent.
-
-Version 1.2.2beta3 [March 7, 2002]
-  Compute background.gray and background_1.gray even when color_type is RGB
-    in case image gets reduced to gray later.
-  Modified shared-library makefiles to install pkgconfig/libpngNN.pc.
-  Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown
-  Removed unused png_write_destroy_info prototype from png.h
-  Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case
-  Added install-shared target to all makefiles that make shared libraries.
-  Stopped a double free of palette, hist, and trans when not using free_me.
-  Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64.
-
-Version 1.2.2beta4 [March 8, 2002]
-  Compute background.gray and background_1.gray even when color_type is RGB
-    in case image gets reduced to gray later (Jason Summers).
-  Relocated a misplaced /bin/rm in the "install-shared" makefile targets
-  Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library.
-
-Version 1.2.2beta5 [March 26, 2002]
-  Added missing PNGAPI to several function definitions.
-  Check for invalid bit_depth or color_type in png_get_IHDR(), and
-    check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen).
-  Revised iTXt support to accept NULL for lang and lang_key.
-  Compute gamma for color components of background even when color_type is gray.
-  Changed "()" to "{}" in scripts/libpng.pc.in.
-  Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN
-  Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so
-
-Version 1.2.2beta6 [March 31, 2002]
-
-Version 1.0.13beta1 [March 31, 2002]
-  Prevent png_zalloc() from trying to memset memory that it failed to acquire.
-  Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate).
-  Ensure that the right function (user or default) is used to free the
-    png_struct after an error in png_create_read_struct_2().
-
-Version 1.2.2rc1 [April 7, 2002]
-
-Version 1.0.13rc1 [April 7, 2002]
-  Save the ebx register in pnggccrd.c (Sami Farin)
-  Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner).
-  Updated makefiles to put headers in include/libpng and remove old include/*.h.
-
-Version 1.2.2 [April 15, 2002]
-
-Version 1.0.13 [April 15, 2002]
-  Revised description of png_set_filter() in libpng.3/libpng.txt.
-  Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd
-
-Version 1.0.13patch01 [April 17, 2002]
-
-Version 1.2.2patch01 [April 17, 2002]
-  Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and
-    makefile.sggcc
-  Fixed VER -> PNGVER typo in makefile.macosx and added install-static to
-    install
-  Added install: target to makefile.32sunu and makefile.64sunu
-
-Version 1.0.13patch03 [April 18, 2002]
-
-Version 1.2.2patch03 [April 18, 2002]
-  Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng
-  subdirectory to libpngNN subdirectory without the full pathname.
-  Moved generation of libpng.pc from "install" to "all" in 15 makefiles.
-
-Version 1.2.3rc1 [April 28, 2002]
-  Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos).
-  Added $(DESTDIR) feature to 24 makefiles (Tim Mooney)
-  Fixed bug with $prefix, should be $(prefix) in makefile.hpux.
-  Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin
-  Added a link from libpngNN.pc to libpng.pc in 15 makefiles.
-  Added links from include/libpngNN/*.h to include/*.h in 24 makefiles.
-  Revised makefile.darwin to make relative links without full pathname.
-  Added setjmp() at the end of png_create_*_struct_2() in case user forgets
-    to put one in their application.
-  Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and
-    removed them from module definition files.
-
-Version 1.2.3rc2 [May 1, 2002]
-  Fixed bug in reporting number of channels in pngget.c and pngset.c,
-    that was introduced in version 1.2.2beta5.
-  Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(),
-    png_default_flush(), and png_push_fill_buffer() and included them in
-    module definition files.
-  Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles.
-
-Version 1.2.3rc3 [May 1, 2002]
-  Revised prototype for png_default_flush()
-  Remove old libpng.pc and libpngNN.pc before installing new ones.
-
-Version 1.2.3rc4 [May 2, 2002]
-  Typos in *.def files (png_default_read|write -> png_default_read|write_data)
-  In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc
-  Added libpng-config and libpngNN-config and modified makefiles to install
-    them.
-  Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles
-  Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp
-
-Version 1.2.3rc5 [May 11, 2002]
-  Changed "error" and "message" in prototypes to "error_message" and
-    "warning_message" to avoid namespace conflict.
-  Revised 15 makefiles to build libpng-config from libpng-config-*.in
-  Once more restored png_zalloc and png_zfree to regular nonexported form.
-  Restored png_default_read|write_data, png_default_flush, png_read_fill_buffer
-    to nonexported form, but with PNGAPI, and removed them from module def
-    files.
-
-Version 1.2.3rc6 [May 14, 2002]
-  Removed "PNGAPI" from png_zalloc() and png_zfree() in png.c
-  Changed "Gz" to "Gd" in projects/msvc/libpng.dsp and zlib.dsp.
-  Removed leftover libpng-config "sed" script from four makefiles.
-  Revised libpng-config creating script in 16 makefiles.
-
-Version 1.2.3 [May 22, 2002]
-  Revised libpng-config target in makefile.cygwin.
-  Removed description of png_set_mem_fn() from documentation.
-  Revised makefile.freebsd.
-  Minor cosmetic changes to 15 makefiles, e.g., $(DI) = $(DESTDIR)/$(INCDIR).
-  Revised projects/msvc/README.txt
-  Changed -lpng to -lpngNN in LDFLAGS in several makefiles.
-
-Version 1.2.4beta1 [May 24, 2002]
-  Added libpng.pc and libpng-config to "all:" target in 16 makefiles.
-  Fixed bug in 16 makefiles: $(DESTDIR)/$(LIBPATH) to $(DESTDIR)$(LIBPATH)
-  Added missing "\" before closing double quote in makefile.gcmmx.
-  Plugged various memory leaks; added png_malloc_warn() and png_set_text_2()
-    functions.
-
-Version 1.2.4beta2 [June 25, 2002]
-  Plugged memory leak of png_ptr->current_text (Matt Holgate).
-  Check for buffer overflow before reading CRC in pngpread.c (Warwick Allison)
-  Added -soname to the loader flags in makefile.dec, makefile.sgi, and
-    makefile.sggcc.
-  Added "test-installed" target to makefile.linux, makefile.gcmmx,
-    makefile.sgi, and makefile.sggcc.
-
-Version 1.2.4beta3 [June 28, 2002]
-  Plugged memory leak of row_buf in pngtest.c when there is a png_error().
-  Detect buffer overflow in pngpread.c when IDAT is corrupted with extra data.
-  Added "test-installed" target to makefile.32sunu, makefile.64sunu,
-    makefile.beos, makefile.darwin, makefile.dec, makefile.macosx,
-    makefile.solaris, makefile.hpux, makefile.hpgcc, and makefile.so9.
-
-Version 1.2.4rc1 and 1.0.14rc1 [July 2, 2002]
-  Added "test-installed" target to makefile.cygwin and makefile.sco.
-  Revised pnggccrd.c to be able to back out version 1.0.x via PNG_1_0_X macro.
-
-Version 1.2.4 and 1.0.14 [July 8, 2002]
-  Changed png_warning() to png_error() when width is too large to process.
-
-Version 1.2.4patch01 [July 20, 2002]
-  Revised makefile.cygwin to use DLL number 12 instead of 13.
-
-Version 1.2.5beta1 [August 6, 2002]
-  Added code to contrib/gregbook/readpng2.c to ignore unused chunks.
-  Replaced toucan.png in contrib/gregbook (it has been corrupt since 1.0.11)
-  Removed some stray *.o files from contrib/gregbook.
-  Changed png_error() to png_warning() about "Too much data" in pngpread.c
-    and about "Extra compressed data" in pngrutil.c.
-  Prevent png_ptr->pass from exceeding 7 in png_push_finish_row().
-  Updated makefile.hpgcc
-  Updated png.c and pnggccrd.c handling of return from png_mmx_support()
-
-Version 1.2.5beta2 [August 15, 2002]
-  Only issue png_warning() about "Too much data" in pngpread.c when avail_in
-    is nonzero.
-  Updated makefiles to install a separate libpng.so.3 with its own rpath.
-
-Version 1.2.5rc1 and 1.0.15rc1 [August 24, 2002]
-  Revised makefiles to not remove previous minor versions of shared libraries.
-
-Version 1.2.5rc2 and 1.0.15rc2 [September 16, 2002]
-  Revised 13 makefiles to remove "-lz" and "-L$(ZLIBLIB)", etc., from shared
-    library loader directive.
-  Added missing "$OBJSDLL" line to makefile.gcmmx.
-  Added missing "; fi" to makefile.32sunu.
-
-Version 1.2.5rc3 and 1.0.15rc3 [September 18, 2002]
-  Revised libpng-config script.
-
-Version 1.2.5 and 1.0.15 [October 3, 2002]
-  Revised makefile.macosx, makefile.darwin, makefile.hpgcc, and makefile.hpux,
-    and makefile.aix.
-  Relocated two misplaced PNGAPI lines in pngtest.c
-
-Version 1.2.6beta1 [October 22, 2002]
-  Commented out warning about uninitialized mmx_support in pnggccrd.c.
-  Changed "IBMCPP__" flag to "__IBMCPP__" in pngconf.h.
-  Relocated two more misplaced PNGAPI lines in pngtest.c
-  Fixed memory overrun bug in png_do_read_filler() with 16-bit datastreams,
-    introduced in version 1.0.2.
-  Revised makefile.macosx, makefile.dec, makefile.aix, and makefile.32sunu.
-
-Version 1.2.6beta2 [November 1, 2002]
-  Added libpng-config "--ldopts" output.
-  Added "AR=ar" and "ARFLAGS=rc" and changed "ar rc" to "$(AR) $(ARFLAGS)"
-    in makefiles.
-
-Version 1.2.6beta3 [July 18, 2004]
-  Reverted makefile changes from version 1.2.6beta2 and some of the changes
-    from version 1.2.6beta1; these will be postponed until version 1.2.7.
-    Version 1.2.6 is going to be a simple bugfix release.
-  Changed the one instance of "ln -sf" to "ln -f -s" in each Sun makefile.
-  Fixed potential overrun in pngerror.c by using strncpy instead of memcpy.
-  Added "#!/bin/sh" at the top of configure, for recognition of the
-    'x' flag under Cygwin (Cosmin).
-  Optimized vacuous tests that silence compiler warnings, in png.c (Cosmin).
-  Added support for PNG_USER_CONFIG, in pngconf.h (Cosmin).
-  Fixed the special memory handler for Borland C under DOS, in pngmem.c
-    (Cosmin).
-  Removed some spurious assignments in pngrutil.c (Cosmin).
-  Replaced 65536 with 65536L, and 0xffff with 0xffffL, to silence warnings
-    on 16-bit platforms (Cosmin).
-  Enclosed shift op expressions in parentheses, to silence warnings (Cosmin).
-  Used proper type png_fixed_point, to avoid problems on 16-bit platforms,
-    in png_handle_sRGB() (Cosmin).
-  Added compression_type to png_struct, and optimized the window size
-    inside the deflate stream (Cosmin).
-  Fixed definition of isnonalpha(), in pngerror.c and pngrutil.c (Cosmin).
-  Fixed handling of unknown chunks that come after IDAT (Cosmin).
-  Allowed png_error() and png_warning() to work even if png_ptr == NULL
-    (Cosmin).
-  Replaced row_info->rowbytes with row_bytes in png_write_find_filter()
-    (Cosmin).
-  Fixed definition of PNG_LIBPNG_VER_DLLNUM (Simon-Pierre).
-  Used PNG_LIBPNG_VER and PNG_LIBPNG_VER_STRING instead of the hardcoded
-    values in png.c (Simon-Pierre, Cosmin).
-  Initialized png_libpng_ver[] with PNG_LIBPNG_VER_STRING (Simon-Pierre).
-  Replaced PNG_LIBPNG_VER_MAJOR with PNG_LIBPNG_VER_DLLNUM in png.rc
-    (Simon-Pierre).
-  Moved the definition of PNG_HEADER_VERSION_STRING near the definitions
-    of the other PNG_LIBPNG_VER_... symbols in png.h (Cosmin).
-  Relocated #ifndef PNGAPI guards in pngconf.h (Simon-Pierre, Cosmin).
-  Updated scripts/makefile.vc(a)win32 (Cosmin).
-  Updated the MSVC project (Simon-Pierre, Cosmin).
-  Updated the Borland C++ Builder project (Cosmin).
-  Avoided access to asm_flags in pngvcrd.c, if PNG_1_0_X is defined (Cosmin).
-  Commented out warning about uninitialized mmx_support in pngvcrd.c (Cosmin).
-  Removed scripts/makefile.bd32 and scripts/pngdef.pas (Cosmin).
-  Added extra guard around inclusion of Turbo C memory headers, in pngconf.h
-    (Cosmin).
-  Renamed projects/msvc/ to projects/visualc6/, and projects/borland/ to
-    projects/cbuilder5/ (Cosmin).
-  Moved projects/visualc6/png32ms.def to scripts/pngw32.def,
-    and projects/visualc6/png.rc to scripts/pngw32.rc (Cosmin).
-  Added projects/visualc6/pngtest.dsp; removed contrib/msvctest/ (Cosmin).
-  Changed line endings to DOS style in cbuilder5 and visualc6 files, even
-    in the tar.* distributions (Cosmin).
-  Updated contrib/visupng/VisualPng.dsp (Cosmin).
-  Updated contrib/visupng/cexcept.h to version 2.0.0 (Cosmin).
-  Added a separate distribution with "configure" and supporting files (Junichi).
-
-Version 1.2.6beta4 [July 28, 2004]
-  Added user ability to change png_size_t via a PNG_SIZE_T macro.
-  Added png_sizeof() and png_convert_size() functions.
-  Added PNG_SIZE_MAX (maximum value of a png_size_t variable.
-  Added check in png_malloc_default() for (size_t)size != (png_uint_32)size
-    which would indicate an overflow.
-  Changed sPLT failure action from png_error to png_warning and abandon chunk.
-  Changed sCAL and iCCP failures from png_error to png_warning and abandon.
-  Added png_get_uint_31(png_ptr, buf) function.
-  Added PNG_UINT_32_MAX macro.
-  Renamed PNG_MAX_UINT to PNG_UINT_31_MAX.
-  Made png_zalloc() issue a png_warning and return NULL on potential
-    overflow.
-  Turn on PNG_NO_ZALLOC_ZERO by default in version 1.2.x
-  Revised "clobber list" in pnggccrd.c so it will compile under gcc-3.4.
-  Revised Borland portion of png_malloc() to return NULL or issue
-    png_error() according to setting of PNG_FLAG_MALLOC_NULL_MEM_OK.
-  Added PNG_NO_SEQUENTIAL_READ_SUPPORTED macro to conditionally remove
-    sequential read support.
-  Added some "#if PNG_WRITE_SUPPORTED" blocks.
-  Added #ifdef to remove some redundancy in png_malloc_default().
-  Use png_malloc instead of png_zalloc to allocate the pallete.
-
-Version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
-  Fixed buffer overflow vulnerability in png_handle_tRNS()
-  Fixed integer arithmetic overflow vulnerability in png_read_png().
-  Fixed some harmless bugs in png_handle_sBIT, etc, that would cause
-    duplicate chunk types to go undetected.
-  Fixed some timestamps in the -config version
-  Rearranged order of processing of color types in png_handle_tRNS().
-  Added ROWBYTES macro to calculate rowbytes without integer overflow.
-  Updated makefile.darwin and removed makefile.macosx from scripts directory.
-  Imposed default one million column, one-million row limits on the image
-    dimensions, and added png_set_user_limits() function to override them.
-  Revised use of PNG_SET_USER_LIMITS_SUPPORTED macro.
-  Fixed wrong cast of returns from png_get_user_width|height_max().
-  Changed some "keep the compiler happy" from empty statements to returns,
-  Revised libpng.txt to remove 1.2.x stuff from the 1.0.x distribution
-
-Version 1.0.16rc2 and 1.2.6rc2 [August 7, 2004]
-  Revised makefile.darwin and makefile.solaris.  Removed makefile.macosx.
-  Revised pngtest's png_debug_malloc() to use png_malloc() instead of
-    png_malloc_default() which is not supposed to be exported.
-  Fixed off-by-one error in one of the conversions to PNG_ROWBYTES() in
-    pngpread.c.  Bug was introduced in 1.2.6rc1.
-  Fixed bug in RGB to RGBX transformation introduced in 1.2.6rc1.
-  Fixed old bug in RGB to Gray transformation.
-  Fixed problem with 64-bit compilers by casting arguments to abs()
-    to png_int_32.
-  Changed "ln -sf" to "ln -f -s" in three makefiles (solaris, sco, so9).
-  Changed "HANDLE_CHUNK_*" to "PNG_HANDLE_CHUNK_*" (Cosmin)
-  Added "-@/bin/rm -f $(DL)/$(LIBNAME).so.$(PNGMAJ)" to 15 *NIX makefiles.
-  Added code to update the row_info->colortype in png_do_read_filler() (MSB).
-
-Version 1.0.16rc3 and 1.2.6rc3 [August 9, 2004]
-  Eliminated use of "abs()" in testing cHRM and gAMA values, to avoid
-    trouble with some 64-bit compilers.  Created PNG_OUT_OF_RANGE() macro.
-  Revised documentation of png_set_keep_unknown_chunks().
-  Check handle_as_unknown status in pngpread.c, as in pngread.c previously.
-  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_INTERNAL section of png.h
-  Added "rim" definitions for CONST4 and CONST6 in pnggccrd.c
-
-Version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004]
-  Fixed mistake in pngtest.c introduced in 1.2.6rc2 (declaration of
-    "pinfo" was out of place).
-
-Version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004]
-  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED
-     section of png.h where they were inadvertently placed in version rc3.
-
-Version 1.2.6 and 1.0.16 [August 15, 2004]
-  Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1.
-
-Version 1.2.7beta1 [August 26, 2004]
-  Removed unused pngasmrd.h file.
-  Removed references to uu.net for archived files.  Added references to
-    PNG Spec (second edition) and the PNG ISO/IEC Standard.
-  Added "test-dd" target in 15 makefiles, to run pngtest in DESTDIR.
-  Fixed bug with "optimized window size" in the IDAT datastream, that
-    causes libpng to write PNG files with incorrect zlib header bytes.
-
-Version 1.2.7beta2 [August 28, 2004]
-  Fixed bug with sCAL chunk and big-endian machines (David Munro).
-  Undid new code added in 1.2.6rc2 to update the color_type in
-    png_set_filler().
-  Added png_set_add_alpha() that updates color type.
-
-Version 1.0.17rc1 and 1.2.7rc1 [September 4, 2004]
-  Revised png_set_strip_filler() to not remove alpha if color_type has alpha.
-
-Version 1.2.7 and 1.0.17 [September 12, 2004]
-  Added makefile.hp64
-  Changed projects/msvc/png32ms.def to scripts/png32ms.def in makefile.cygwin
-
-Version 1.2.8beta1 [November 1, 2004]
-  Fixed bug in png_text_compress() that would fail to complete a large block.
-  Fixed bug, introduced in libpng-1.2.7, that overruns a buffer during
-    strip alpha operation in png_do_strip_filler().
-  Added PNG_1_2_X definition in pngconf.h
-  Use #ifdef to comment out png_info_init in png.c and png_read_init in
-    pngread.c (as of 1.3.0)
-
-Version 1.2.8beta2 [November 2, 2004]
-  Reduce color_type to a nonalpha type after strip alpha operation in
-    png_do_strip_filler().
-
-Version 1.2.8beta3 [November 3, 2004]
-  Revised definitions of PNG_MAX_UINT_32, PNG_MAX_SIZE, and PNG_MAXSUM
-
-Version 1.2.8beta4 [November 12, 2004]
-  Fixed (again) definition of PNG_LIBPNG_VER_DLLNUM in png.h (Cosmin).
-  Added PNG_LIBPNG_BUILD_PRIVATE in png.h (Cosmin).
-  Set png_ptr->zstream.data_type to Z_BINARY, to avoid unnecessary detection
-    of data type in deflate (Cosmin).
-  Deprecated but continue to support SPECIALBUILD and PRIVATEBUILD in favor of
-    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
-
-Version 1.2.8beta5 [November 20, 2004]
-  Use png_ptr->flags instead of png_ptr->transformations to pass
-    PNG_STRIP_ALPHA info to png_do_strip_filler(), to preserve ABI
-    compatibility.
-  Revised handling of SPECIALBUILD, PRIVATEBUILD,
-    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
-
-Version 1.2.8rc1 [November 24, 2004]
-  Moved handling of BUILD macros from pngconf.h to png.h
-  Added definition of PNG_LIBPNG_BASE_TYPE in png.h, inadvertently
-    omitted from beta5.
-  Revised scripts/pngw32.rc
-  Despammed mailing addresses by masking "@" with "at".
-  Inadvertently installed a supposedly faster test version of pngrutil.c
-
-Version 1.2.8rc2 [November 26, 2004]
-  Added two missing "\" in png.h
-  Change tests in pngread.c and pngpread.c to
-    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
-       png_do_read_transformations(png_ptr);
-
-Version 1.2.8rc3 [November 28, 2004]
-  Reverted pngrutil.c to version libpng-1.2.8beta5.
-  Added scripts/makefile.elf with supporting code in pngconf.h for symbol
-    versioning (John Bowler).
-
-Version 1.2.8rc4 [November 29, 2004]
-  Added projects/visualc7 (Simon-pierre).
-
-Version 1.2.8rc5 [November 29, 2004]
-  Fixed new typo in scripts/pngw32.rc
-
-Version 1.2.8 [December 3, 2004]
-  Removed projects/visualc7, added projects/visualc71.
-
-Version 1.2.9beta1 [February 21, 2006]
-  Initialized some structure members in pngwutil.c to avoid gcc-4.0.0 complaints
-  Revised man page and libpng.txt to make it clear that one should not call
-    png_read_end or png_write_end after png_read_png or png_write_png.
-  Updated references to png-mng-implement mailing list.
-  Fixed an incorrect typecast in pngrutil.c
-  Added PNG_NO_READ_SUPPORTED conditional for making a write-only library.
-  Added PNG_NO_WRITE_INTERLACING_SUPPORTED conditional.
-  Optimized alpha-inversion loops in pngwtran.c
-  Moved test for nonzero gamma outside of png_build_gamma_table() in pngrtran.c
-  Make sure num_trans is <= 256 before copying data in png_set_tRNS().
-  Make sure num_palette is <= 256 before copying data in png_set_PLTE().
-  Interchanged order of write_swap_alpha and write_invert_alpha transforms.
-  Added parentheses in the definition of PNG_LIBPNG_BUILD_TYPE (Cosmin).
-  Optimized zlib window flag (CINFO) in contrib/pngsuite/*.png (Cosmin).
-  Updated scripts/makefile.bc32 for Borland C++ 5.6 (Cosmin).
-  Exported png_get_uint_32, png_save_uint_32, png_get_uint_16, png_save_uint_16,
-    png_get_int_32, png_save_int_32, png_get_uint_31 (Cosmin).
-  Added type cast (png_byte) in png_write_sCAL() (Cosmin).
-  Fixed scripts/makefile.cygwin (Christian Biesinger, Cosmin).
-  Default iTXt support was inadvertently enabled.
-
-Version 1.2.9beta2 [February 21, 2006]
-  Check for png_rgb_to_gray and png_gray_to_rgb read transformations before
-    checking for png_read_dither in pngrtran.c
-  Revised checking of chromaticity limits to accommodate extended RGB
-    colorspace (John Denker).
-  Changed line endings in some of the project files to CRLF, even in the
-    "Unix" tar distributions (Cosmin).
-  Made png_get_int_32 and png_save_int_32 always available (Cosmin).
-  Updated scripts/pngos2.def, scripts/pngw32.def and projects/wince/png32ce.def
-    with the newly exported functions.
-  Eliminated distributions without the "configure" script.
-  Updated INSTALL instructions.
-
-Version 1.2.9beta3 [February 24, 2006]
-  Fixed CRCRLF line endings in contrib/visupng/VisualPng.dsp
-  Made libpng.pc respect EXEC_PREFIX (D. P. Kreil, J. Bowler)
-  Removed reference to pngasmrd.h from Makefile.am
-  Renamed CHANGES to ChangeLog.
-  Renamed LICENSE to COPYING.
-  Renamed ANNOUNCE to NEWS.
-  Created AUTHORS file.
-
-Version 1.2.9beta4 [March 3, 2006]
-  Changed definition of PKGCONFIG from $prefix/lib to $libdir in configure.ac
-  Reverted to filenames LICENSE and ANNOUNCE; removed AUTHORS and COPYING.
-  Removed newline from the end of some error and warning messages.
-  Removed test for sqrt() from configure.ac and configure.
-  Made swap tables in pngtrans.c PNG_CONST (Carlo Bramix).
-  Disabled default iTXt support that was inadvertently enabled in
-    libpng-1.2.9beta1.
-  Added "OS2" to list of systems that don't need underscores, in pnggccrd.c
-  Removed libpng version and date from *.c files.
-
-Version 1.2.9beta5 [March 4, 2006]
-  Removed trailing blanks from source files.
-  Put version and date of latest change in each source file, and changed
-    copyright year accordingly.
-  More cleanup of configure.ac, Makefile.am, and associated scripts.
-  Restored scripts/makefile.elf which was inadvertently deleted.
-
-Version 1.2.9beta6 [March 6, 2006]
-  Fixed typo (RELEASE) in configuration files.
-
-Version 1.2.9beta7 [March 7, 2006]
-  Removed libpng.vers and libpng.sym from libpng12_la_SOURCES in Makefile.am
-  Fixed inconsistent #ifdef's around png_sig_bytes() and png_set_sCAL_s()
-    in png.h.
-  Updated makefile.elf as suggested by debian.
-  Made cosmetic changes to some makefiles, adding LN_SF and other macros.
-  Made some makefiles accept "exec_prefix".
-
-Version 1.2.9beta8 [March 9, 2006]
-  Fixed some "#if defined (..." which should be "#if defined(..."
-    Bug introduced in libpng-1.2.8.
-  Fixed inconsistency in definition of png_default_read_data()
-  Restored blank that was lost from makefile.sggcc "clean" target in beta7.
-  Revised calculation of "current" and "major" for irix in ltmain.sh
-  Changed "mkdir" to "MKDIR_P" in some makefiles.
-  Separated PNG_EXPAND and PNG_EXPAND_tRNS.
-  Added png_set_expand_gray_1_2_4_to_8() and deprecated
-    png_set_gray_1_2_4_to_8() which also expands tRNS to alpha.
-
-Version 1.2.9beta9 [March 10, 2006]
-  Include "config.h" in pngconf.h when available.
-  Added some checks for NULL png_ptr or NULL info_ptr (timeless)
-
-Version 1.2.9beta10 [March 20, 2006]
-  Removed extra CR from contrib/visualpng/VisualPng.dsw (Cosmin)
-  Made pnggccrd.c PIC-compliant (Christian Aichinger).
-  Added makefile.mingw (Wolfgang Glas).
-  Revised pngconf.h MMX checking.
-
-Version 1.2.9beta11 [March 22, 2006]
-  Fixed out-of-order declaration in pngwrite.c that was introduced in beta9
-  Simplified some makefiles by using LIBSO, LIBSOMAJ, and LIBSOVER macros.
-
-Version 1.2.9rc1 [March 31, 2006]
-  Defined PNG_USER_PRIVATEBUILD when including "pngusr.h" (Cosmin).
-  Removed nonsensical assertion check from pngtest.c (Cosmin).
-
-Version 1.2.9 [April 14, 2006]
-  Revised makefile.beos and added "none" selector in ltmain.sh
-
-Version 1.2.10beta1 [April 15, 2006]
-  Renamed "config.h" to "png_conf.h" and revised Makefile.am to add
-    -DPNG_BUILDING_LIBPNG to compile directive, and modified pngconf.h
-    to include png_conf.h only when PNG_BUILDING_LIBPNG is defined.
-
-Version 1.2.10beta2 [April 15, 2006]
-  Manually updated Makefile.in and configure.  Changed png_conf.h.in
-    back to config.h.
-
-Version 1.2.10beta3 [April 15, 2006]
-  Change png_conf.h back to config.h in pngconf.h.
-
-Version 1.2.10beta4 [April 16, 2006]
-  Change PNG_BUILDING_LIBPNG to PNG_CONFIGURE_LIBPNG in config/Makefile*.
-
-Version 1.2.10beta5 [April 16, 2006]
-  Added a configure check for compiling assembler code in pnggccrd.c
-
-Version 1.2.10beta6 [April 17, 2006]
-  Revised the configure check for pnggccrd.c
-  Moved -DPNG_CONFIGURE_LIBPNG into @LIBPNG_DEFINES@
-  Added @LIBPNG_DEFINES@ to arguments when building libpng.sym
-
-Version 1.2.10beta7 [April 18, 2006]
-  Change "exec_prefix=$prefix" to "exec_prefix=$(prefix)" in makefiles.
-
-Version 1.2.10rc1 [April 19, 2006]
-  Ensure pngconf.h doesn't define both PNG_USE_PNGGCCRD and PNG_USE_PNGVCRD
-  Fixed "LN_FS" typo in makefile.sco and makefile.solaris.
-
-Version 1.2.10rc2 [April 20, 2006]
-  Added a backslash between -DPNG_CONFIGURE_LIBPNG and -DPNG_NO_ASSEMBLER_CODE
-   in configure.ac and configure
-  Made the configure warning about versioned symbols less arrogant.
-
-Version 1.2.10rc3 [April 21, 2006]
-  Added a note in libpng.txt that png_set_sig_bytes(8) can be used when
-    writing an embedded PNG without the 8-byte signature.
-  Revised makefiles and configure to avoid making links to libpng.so.*
-
-Version 1.2.10 [April 23, 2006]
-  Reverted configure to "rc2" state.
-
-Version 1.2.11beta1 [May 31, 2006]
-  scripts/libpng.pc.in contained "configure" style version info and would
-    not work with makefiles.
-  The shared-library makefiles were linking to libpng.so.0 instead of
-    libpng.so.3 compatibility as the library.
-
-Version 1.2.11beta2 [June 2, 2006]
-  Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
-    buffer overflow.
-  Fixed bug in example.c (png_set_palette_rgb -> png_set_palette_to_rgb)
-
-Version 1.2.11beta3 [June 5, 2006]
-  Prepended "#! /bin/sh" to ltmail.sh and contrib/pngminus/*.sh (Cosmin).
-  Removed the accidental leftover Makefile.in~ (Cosmin).
-  Avoided potential buffer overflow and optimized buffer in
-    png_write_sCAL(), png_write_sCAL_s() (Cosmin).
-  Removed the include directories and libraries from CFLAGS and LDFLAGS
-    in scripts/makefile.gcc (Nelson A. de Oliveira, Cosmin).
-
-Version 1.2.11beta4 [June 6, 2006]
-  Allow zero-length IDAT chunks after the entire zlib datastream, but not
-    after another intervening chunk type.
-
-Version 1.0.19rc1, 1.2.11rc1 [June 13, 2006]
-  Deleted extraneous square brackets from [config.h] in configure.ac
-
-Version 1.0.19rc2, 1.2.11rc2 [June 14, 2006]
-  Added prototypes for PNG_INCH_CONVERSIONS functions to png.h
-  Revised INSTALL and autogen.sh
-  Fixed typo in several makefiles (-W1 should be -Wl)
-  Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
-
-Version 1.0.19rc3, 1.2.11rc3 [June 15, 2006]
-  Removed the new typedefs for 64-bit systems (delay until version 1.4.0)
-  Added one zero element to png_gamma_shift[] array in pngrtran.c to avoid
-    reading out of bounds.
-
-Version 1.0.19rc4, 1.2.11rc4 [June 15, 2006]
-  Really removed the new typedefs for 64-bit systems.
-
-Version 1.0.19rc5, 1.2.11rc5 [June 22, 2006]
-  Removed png_sig_bytes entry from scripts/pngw32.def
-
-Version 1.0.19, 1.2.11 [June 26, 2006]
-  None.
-
-Version 1.0.20, 1.2.12 [June 27, 2006]
-  Really increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
-    buffer overflow.
-
-Version 1.2.13beta1 [October 2, 2006]
-  Removed AC_FUNC_MALLOC from configure.ac
-  Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
-  Change "logical" to "bitwise" throughout documentation.
-  Detect and fix attempt to write wrong iCCP profile length (CVE-2006-7244)
-
-Version 1.0.21, 1.2.13 [November 14, 2006]
-  Fix potential buffer overflow in sPLT chunk handler.
-  Fix Makefile.am to not try to link to noexistent files.
-  Check all exported functions for NULL png_ptr.
-
-Version 1.2.14beta1 [November 17, 2006]
-  Relocated three misplaced tests for NULL png_ptr.
-  Built Makefile.in with automake-1.9.6 instead of 1.9.2.
-  Build configure with autoconf-2.60 instead of 2.59
-
-Version 1.2.14beta2 [November 17, 2006]
-  Added some typecasts in png_zalloc().
-
-Version 1.2.14rc1 [November 20, 2006]
-  Changed "strtod" to "png_strtod" in pngrutil.c
-
-Version 1.0.22, 1.2.14    [November 27, 2006]
-  Added missing "$(srcdir)" in Makefile.am and Makefile.in
-
-Version 1.2.15beta1 [December 3, 2006]
-  Generated configure with autoconf-2.61 instead of 2.60
-  Revised configure.ac to update libpng.pc and libpng-config.
-
-Version 1.2.15beta2 [December 3, 2006]
-  Always export MMX asm functions, just stubs if not building pnggccrd.c
-
-Version 1.2.15beta3 [December 4, 2006]
-  Add "png_bytep" typecast to profile while calculating length in pngwutil.c
-
-Version 1.2.15beta4 [December 7, 2006]
-  Added scripts/CMakeLists.txt
-  Changed PNG_NO_ASSEMBLER_CODE to PNG_NO_MMX_CODE in scripts, like 1.4.0beta
-
-Version 1.2.15beta5 [December 7, 2006]
-  Changed some instances of PNG_ASSEMBLER_* to PNG_MMX_* in pnggccrd.c
-  Revised scripts/CMakeLists.txt
-
-Version 1.2.15beta6 [December 13, 2006]
-  Revised scripts/CMakeLists.txt and configure.ac
-
-Version 1.2.15rc1 [December 18, 2006]
-  Revised scripts/CMakeLists.txt
-
-Version 1.2.15rc2 [December 21, 2006]
-  Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
-  Added scripts/makefile.nommx
-
-Version 1.2.15rc3 [December 25, 2006]
-  Fixed shared library numbering error that was introduced in 1.2.15beta6.
-
-Version 1.2.15rc4 [December 27, 2006]
-  Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set.
-
-Version 1.2.15rc5 [December 31, 2006]
-  Revised handling of rgb_to_gray.
-
-Version 1.2.15 [January 5, 2007]
-  Added some (unsigned long) typecasts in pngtest.c to avoid printing errors.
-
-Version 1.2.16beta1 [January 6, 2007]
-  Fix bugs in makefile.nommx
-
-Version 1.2.16beta2 [January 16, 2007]
-  Revised scripts/CMakeLists.txt
-
-Version 1.2.16 [January 31, 2007]
-  No changes.
-
-Version 1.2.17beta1 [March 6, 2007]
-  Revised scripts/CMakeLists.txt to install both shared and static libraries.
-  Deleted a redundant line from pngset.c.
-
-Version 1.2.17beta2 [April 26, 2007]
-  Relocated misplaced test for png_ptr == NULL in pngpread.c
-  Change "==" to "&" for testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN
-    flags.
-  Changed remaining instances of PNG_ASSEMBLER_* to PNG_MMX_*
-  Added pngerror() when write_IHDR fails in deflateInit2().
-  Added "const" to some array declarations.
-  Mention examples of libpng usage in the libpng*.txt and libpng.3 documents.
-
-Version 1.2.17rc1 [May 4, 2007]
-  No changes.
-
-Version 1.2.17rc2 [May 8, 2007]
-  Moved several PNG_HAVE_* macros out of PNG_INTERNAL because applications
-    calling set_unknown_chunk_location() need them.
-  Changed transformation flag from PNG_EXPAND_tRNS to PNG_EXPAND in
-    png_set_expand_gray_1_2_4_to_8().
-  Added png_ptr->unknown_chunk to hold working unknown chunk data, so it
-    can be free'ed in case of error.  Revised unknown chunk handling in
-    pngrutil.c and pngpread.c to use this structure.
-
-Version 1.2.17rc3 [May 8, 2007]
-  Revised symbol-handling in configure script.
-
-Version 1.2.17rc4 [May 10, 2007]
-  Revised unknown chunk handling to avoid storing unknown critical chunks.
-
-Version 1.0.25 [May 15, 2007]
-Version 1.2.17 [May 15, 2007]
-  Added "png_ptr->num_trans=0" before error return in png_handle_tRNS,
-    to eliminate a vulnerability (CVE-2007-2445, CERT VU#684664)
-
-Version 1.0.26 [May 15, 2007]
-Version 1.2.18 [May 15, 2007]
-  Reverted the libpng-1.2.17rc3 change to symbol-handling in configure script
-
-Version 1.2.19beta1 [May 18, 2007]
-  Changed "const static" to "static PNG_CONST" everywhere, mostly undoing
-    change of libpng-1.2.17beta2.  Changed other "const" to "PNG_CONST"
-  Changed some handling of unused parameters, to avoid compiler warnings.
-    "if (unused == NULL) return;" becomes "unused = unused".
-
-Version 1.2.19beta2 [May 18, 2007]
-  Only use the valid bits of tRNS value in png_do_expand() (Brian Cartier)
-
-Version 1.2.19beta3 [May 19, 2007]
-  Add some "png_byte" typecasts in png_check_keyword() and write new_key
-  instead of key in zTXt chunk (Kevin Ryde).
-
-Version 1.2.19beta4 [May 21, 2007]
-  Add png_snprintf() function and use it in place of sprint() for improved
-    defense against buffer overflows.
-
-Version 1.2.19beta5 [May 21, 2007]
-  Fixed png_handle_tRNS() to only use the valid bits of tRNS value.
-  Changed handling of more unused parameters, to avoid compiler warnings.
-  Removed some PNG_CONST in pngwutil.c to avoid compiler warnings.
-
-Version 1.2.19beta6 [May 22, 2007]
-  Added some #ifdef PNG_MMX_CODE_SUPPORTED where needed in pngvcrd.c
-  Added a special "_MSC_VER" case that defines png_snprintf to _snprintf
-
-Version 1.2.19beta7 [May 22, 2007]
-  Squelched png_squelch_warnings() in pnggccrd.c and added
-    an #ifdef PNG_MMX_CODE_SUPPORTED block around the declarations that caused
-    the warnings that png_squelch_warnings was squelching.
-
-Version 1.2.19beta8 [May 22, 2007]
-  Removed __MMX__ from test in pngconf.h.
-
-Version 1.2.19beta9 [May 23, 2007]
-  Made png_squelch_warnings() available via PNG_SQUELCH_WARNINGS macro.
-  Revised png_squelch_warnings() so it might work.
-  Updated makefile.sgcc and makefile.solaris; added makefile.solaris-x86.
-
-Version 1.2.19beta10 [May 24, 2007]
-  Resquelched png_squelch_warnings(), use "__attribute__((used))" instead.
-
-Version 1.4.0beta1 [April 20, 2006]
-  Enabled iTXt support (changes png_struct, thus requires so-number change).
-  Cleaned up PNG_ASSEMBLER_CODE_SUPPORTED vs PNG_MMX_CODE_SUPPORTED
-  Eliminated PNG_1_0_X and PNG_1_2_X macros.
-  Removed deprecated functions png_read_init, png_write_init, png_info_init,
-    png_permit_empty_plte, png_set_gray_1_2_4_to_8, png_check_sig, and
-    removed the deprecated macro PNG_MAX_UINT.
-  Moved "PNG_INTERNAL" parts of png.h and pngconf.h into pngintrn.h
-  Removed many WIN32_WCE #ifdefs (Cosmin).
-  Reduced dependency on C-runtime library when on Windows (Simon-Pierre)
-  Replaced sprintf() with png_sprintf() (Simon-Pierre)
-
-Version 1.4.0beta2 [April 20, 2006]
-  Revised makefiles and configure to avoid making links to libpng.so.*
-  Moved some leftover MMX-related defines from pngconf.h to pngintrn.h
-  Updated scripts/pngos2.def, pngw32.def, and projects/wince/png32ce.def
-
-Version 1.4.0beta3 [May 10, 2006]
-  Updated scripts/pngw32.def to comment out MMX functions.
-  Added PNG_NO_GET_INT_32 and PNG_NO_SAVE_INT_32 macros.
-  Scripts/libpng.pc.in contained "configure" style version info and would
-    not work with makefiles.
-  Revised pngconf.h and added pngconf.h.in, so makefiles and configure can
-    pass defines to libpng and applications.
-
-Version 1.4.0beta4 [May 11, 2006]
-  Revised configure.ac, Makefile.am, and many of the makefiles to write
-    their defines in pngconf.h.
-
-Version 1.4.0beta5 [May 15, 2006]
-  Added a missing semicolon in Makefile.am and Makefile.in
-  Deleted extraneous square brackets from configure.ac
-
-Version 1.4.0beta6 [June 2, 2006]
-  Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
-    buffer overflow.
-  Changed sonum from 0 to 1.
-  Removed unused prototype for png_check_sig() from png.h
-
-Version 1.4.0beta7 [June 16, 2006]
-  Exported png_write_sig (Cosmin).
-  Optimized buffer in png_handle_cHRM() (Cosmin).
-  Set pHYs = 2835 x 2835 pixels per meter, and added
-    sCAL = 0.352778e-3 x 0.352778e-3 meters, in pngtest.png (Cosmin).
-  Added png_set_benign_errors(), png_benign_error(), png_chunk_benign_error().
-  Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
-  Added "(unsigned long)" typecast on png_uint_32 variables in printf lists.
-
-Version 1.4.0beta8 [June 22, 2006]
-  Added demonstration of user chunk support in pngtest.c, to support the
-    public sTER chunk and a private vpAg chunk.
-
-Version 1.4.0beta9 [July 3, 2006]
-  Removed ordinals from scripts/pngw32.def and removed png_info_int and
-    png_set_gray_1_2_4_to_8 entries.
-  Inline call of png_get_uint_32() in png_get_uint_31().
-  Use png_get_uint_31() to get vpAg width and height in pngtest.c
-  Removed WINCE and Netware projects.
-  Removed standalone Y2KINFO file.
-
-Version 1.4.0beta10 [July 12, 2006]
-  Eliminated automatic copy of pngconf.h to pngconf.h.in from configure and
-    some makefiles, because it was not working reliably.  Instead, distribute
-    pngconf.h.in along with pngconf.h and cause configure and some of the
-    makefiles to update pngconf.h from pngconf.h.in.
-  Added pngconf.h to DEPENDENCIES in Makefile.am
-
-Version 1.4.0beta11 [August 19, 2006]
-  Removed AC_FUNC_MALLOC from configure.ac.
-  Added a warning when writing iCCP profile with mismatched profile length.
-  Patched pnggccrd.c to assemble on x86_64 platforms.
-  Moved chunk header reading into a separate function png_read_chunk_header()
-    in pngrutil.c.  The chunk header (len+sig) is now serialized in a single
-    operation (Cosmin).
-  Implemented support for I/O states. Added png_ptr member io_state, and
-    functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
-    (Cosmin).
-  Added png_get_io_chunk_name and png_get_io_state to scripts/*.def (Cosmin).
-  Renamed scripts/pngw32.* to scripts/pngwin.* (Cosmin).
-  Removed the include directories and libraries from CFLAGS and LDFLAGS
-    in scripts/makefile.gcc (Cosmin).
-  Used png_save_uint_32() to set vpAg width and height in pngtest.c (Cosmin).
-  Cast to proper type when getting/setting vpAg units in pngtest.c (Cosmin).
-  Added pngintrn.h to the Visual C++ projects (Cosmin).
-  Removed scripts/list (Cosmin).
-  Updated copyright year in scripts/pngwin.def (Cosmin).
-  Removed PNG_TYPECAST_NULL and used standard NULL consistently (Cosmin).
-  Disallowed the user to redefine png_size_t, and enforced a consistent use
-    of png_size_t across libpng (Cosmin).
-  Changed the type of png_ptr->rowbytes, PNG_ROWBYTES() and friends
-    to png_size_t (Cosmin).
-  Removed png_convert_size() and replaced png_sizeof with sizeof (Cosmin).
-  Removed some unnecessary type casts (Cosmin).
-  Changed prototype of png_get_compression_buffer_size() and
-    png_set_compression_buffer_size() to work with png_size_t instead of
-    png_uint_32 (Cosmin).
-  Removed png_memcpy_check() and png_memset_check() (Cosmin).
-  Fixed a typo (png_byte --> png_bytep) in libpng.3 and libpng.txt (Cosmin).
-  Clarified that png_zalloc() does not clear the allocated memory,
-    and png_zalloc() and png_zfree() cannot be PNGAPI (Cosmin).
-  Renamed png_mem_size_t to png_alloc_size_t, fixed its definition in
-    pngconf.h, and used it in all memory allocation functions (Cosmin).
-  Renamed pngintrn.h to pngpriv.h, added a comment at the top of the file
-    mentioning that the symbols declared in that file are private, and
-    updated the scripts and the Visual C++ projects accordingly (Cosmin).
-  Removed circular references between pngconf.h and pngconf.h.in in
-    scripts/makefile.vc*win32 (Cosmin).
-  Removing trailing '.' from the warning and error messages (Cosmin).
-  Added pngdefs.h that is built by makefile or configure, instead of
-    pngconf.h.in (Glenn).
-  Detect and fix attempt to write wrong iCCP profile length.
-
-Version 1.4.0beta12 [October 19, 2006]
-  Changed "logical" to "bitwise" in the documentation.
-  Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
-  Add a typecast to stifle compiler warning in pngrutil.c
-
-Version 1.4.0beta13 [November 10, 2006]
-  Fix potential buffer overflow in sPLT chunk handler.
-  Fix Makefile.am to not try to link to noexistent files.
-
-Version 1.4.0beta14 [November 15, 2006]
-  Check all exported functions for NULL png_ptr.
-
-Version 1.4.0beta15 [November 17, 2006]
-  Relocated two misplaced tests for NULL png_ptr.
-  Built Makefile.in with automake-1.9.6 instead of 1.9.2.
-  Build configure with autoconf-2.60 instead of 2.59
-  Add "install: all" in Makefile.am so "configure; make install" will work.
-
-Version 1.4.0beta16 [November 17, 2006]
-  Added a typecast in png_zalloc().
-
-Version 1.4.0beta17 [December 4, 2006]
-  Changed "new_key[79] = '\0';" to "(*new_key)[79] = '\0';" in pngwutil.c
-  Add "png_bytep" typecast to profile while calculating length in pngwutil.c
-
-Version 1.4.0beta18 [December 7, 2006]
-  Added scripts/CMakeLists.txt
-
-Version 1.4.0beta19 [May 16, 2007]
-  Revised scripts/CMakeLists.txt
-  Rebuilt configure and Makefile.in with newer tools.
-  Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
-  Added scripts/makefile.nommx
-
-Version 1.4.0beta20 [July 9, 2008]
-  Moved several PNG_HAVE_* macros from pngpriv.h to png.h because applications
-    calling set_unknown_chunk_location() need them.
-  Moved several macro definitions from pngpriv.h to pngconf.h
-  Merge with changes to the 1.2.X branch, as of 1.2.30beta04.
-  Deleted all use of the MMX assembler code and Intel-licensed optimizations.
-  Revised makefile.mingw
-
-Version 1.4.0beta21 [July 21, 2008]
-  Moved local array "chunkdata" from pngrutil.c to the png_struct, so
-    it will be freed by png_read_destroy() in case of a read error (Kurt
-    Christensen).
-
-Version 1.4.0beta22 [July 21, 2008]
-  Change "purpose" and "buffer" to png_ptr->chunkdata to avoid memory leaking.
-
-Version 1.4.0beta23 [July 22, 2008]
-  Change "chunkdata = NULL" to "png_ptr->chunkdata = NULL" several places in
-    png_decompress_chunk().
-
-Version 1.4.0beta24 [July 25, 2008]
-  Change all remaining "chunkdata" to "png_ptr->chunkdata" in
-    png_decompress_chunk(), and remove "chunkdata" from parameter list.
-  Put a call to png_check_chunk_name() in png_read_chunk_header().
-  Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte.
-  Removed two calls to png_check_chunk_name() occuring later in the process.
-  Define PNG_NO_ERROR_NUMBERS by default in pngconf.h
-
-Version 1.4.0beta25 [July 30, 2008]
-  Added a call to png_check_chunk_name() in pngpread.c
-  Reverted png_check_chunk_name() to accept a name with a lowercase 3rd byte.
-  Added png_push_have_buffer() function to pngpread.c
-  Eliminated PNG_BIG_ENDIAN_SUPPORTED and associated png_get_* macros.
-  Made inline expansion of png_get_*() optional with PNG_USE_READ_MACROS.
-  Eliminated all PNG_USELESS_TESTS and PNG_CORRECT_PALETTE_SUPPORTED code.
-  Synced contrib directory and configure files with libpng-1.2.30beta06.
-  Eliminated no-longer-used pngdefs.h (but it's still built in the makefiles)
-  Relocated a misplaced "#endif /* PNG_NO_WRITE_FILTER */" in pngwutil.c
-
-Version 1.4.0beta26 [August 4, 2008]
-  Removed png_push_have_buffer() function in pngpread.c.  It increased the
-    compiled library size slightly.
-  Changed "-Wall" to "-W -Wall" in the CFLAGS in all makefiles (Cosmin Truta)
-  Declared png_ptr "volatile" in pngread.c and pngwrite.c to avoid warnings.
-  Updated contrib/visupng/cexcept.h to version 2.0.1
-  Added PNG_LITERAL_CHARACTER macros for #, [, and ].
-
-Version 1.4.0beta27 [August 5, 2008]
-  Revised usage of PNG_LITERAL_SHARP in pngerror.c.
-  Moved newline character from individual png_debug messages into the
-    png_debug macros.
-  Allow user to #define their own png_debug, png_debug1, and png_debug2.
-
-Version 1.4.0beta28 [August 5, 2008]
-  Revised usage of PNG_LITERAL_SHARP in pngerror.c.
-  Added PNG_STRING_NEWLINE macro
-
-Version 1.4.0beta29 [August 9, 2008]
-  Revised usage of PNG_STRING_NEWLINE to work on non-ISO compilers.
-  Added PNG_STRING_COPYRIGHT macro.
-  Added non-ISO versions of png_debug macros.
-
-Version 1.4.0beta30 [August 14, 2008]
-  Added premultiplied alpha feature (Volker Wiendl).
-
-Version 1.4.0beta31 [August 18, 2008]
-  Moved png_set_premultiply_alpha from pngtrans.c to pngrtran.c
-  Removed extra crc check at the end of png_handle_cHRM().  Bug introduced
-    in libpng-1.4.0beta20.
-
-Version 1.4.0beta32 [August 19, 2008]
-  Added PNG_WRITE_FLUSH_SUPPORTED block around new png_flush() call.
-  Revised PNG_NO_STDIO version of png_write_flush()
-
-Version 1.4.0beta33 [August 20, 2008]
-  Added png_get|set_chunk_cache_max() to limit the total number of sPLT,
-    text, and unknown chunks that can be stored.
-
-Version 1.4.0beta34 [September 6, 2008]
-  Shortened tIME_string to 29 bytes in pngtest.c
-  Fixed off-by-one error introduced in png_push_read_zTXt() function in
-    libpng-1.2.30beta04/pngpread.c (Harald van Dijk)
-
-Version 1.4.0beta35 [October 6, 2008]
-  Changed "trans_values" to "trans_color".
-  Changed so-number from 0 to 14.  Some OS do not like 0.
-  Revised makefile.darwin to fix shared library numbering.
-  Change png_set_gray_1_2_4_to_8() to png_set_expand_gray_1_2_4_to_8()
-    in example.c (debian bug report)
-
-Version 1.4.0beta36 [October 25, 2008]
-  Sync with tEXt vulnerability fix in libpng-1.2.33rc02.
-
-Version 1.4.0beta37 [November 13, 2008]
-  Added png_check_cHRM in png.c and moved checking from pngget.c, pngrutil.c,
-    and pngwrite.c
-
-Version 1.4.0beta38 [November 22, 2008]
-  Added check for zero-area RGB cHRM triangle in png_check_cHRM() and
-    png_check_cHRM_fixed().
-
-Version 1.4.0beta39 [November 23, 2008]
-  Revised png_warning() to write its message on standard output by default
-    when warning_fn is NULL.
-
-Version 1.4.0beta40 [November 24, 2008]
-  Eliminated png_check_cHRM().  Instead, always use png_check_cHRM_fixed().
-  In png_check_cHRM_fixed(), ensure white_y is > 0, and removed redundant
-    check for all-zero coordinates that is detected by the triangle check.
-
-Version 1.4.0beta41 [November 26, 2008]
-  Fixed string vs pointer-to-string error in png_check_keyword().
-  Rearranged test expressions in png_check_cHRM_fixed() to avoid internal
-    overflows.
-  Added PNG_NO_CHECK_cHRM conditional.
-
-Version 1.4.0beta42, 43 [December 1, 2008]
-  Merge png_debug with version 1.2.34beta04.
-
-Version 1.4.0beta44 [December 6, 2008]
-  Removed redundant check for key==NULL before calling png_check_keyword()
-    to ensure that new_key gets initialized and removed extra warning
-    (Merge with version 1.2.34beta05 -- Arvan Pritchard).
-
-Version 1.4.0beta45 [December 9, 2008]
-  In png_write_png(), respect the placement of the filler bytes in an earlier
-    call to png_set_filler() (Jim Barry).
-
-Version 1.4.0beta46 [December 10, 2008]
-  Undid previous change and added PNG_TRANSFORM_STRIP_FILLER_BEFORE and
-    PNG_TRANSFORM_STRIP_FILLER_AFTER conditionals and deprecated
-    PNG_TRANSFORM_STRIP_FILLER (Jim Barry).
-
-Version 1.4.0beta47 [December 15, 2008]
-  Support for dithering was disabled by default, because it has never
-    been well tested and doesn't work very well.  The code has not
-    been removed, however, and can be enabled by building libpng with
-    PNG_READ_DITHER_SUPPORTED defined.
-
-Version 1.4.0beta48 [February 14, 2009]
-  Added new exported function png_calloc().
-  Combined several instances of png_malloc(); png_memset() into png_calloc().
-  Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
-    but was never defined.
-
-Version 1.4.0beta49 [February 28, 2009]
-  Added png_fileno() macro to pngconf.h, used in pngwio.c
-  Corrected order of #ifdef's in png_debug definition in png.h
-  Fixed bug introduced in libpng-1.4.0beta48 with the memset arguments
-    for pcal_params.
-  Fixed order of #ifdef directives in the png_debug defines in png.h
-    (bug introduced in libpng-1.2.34/1.4.0beta29).
-  Revised comments in png_set_read_fn() and png_set_write_fn().
-
-Version 1.4.0beta50 [March 18, 2009]
-  Use png_calloc() instead of png_malloc() to allocate big_row_buf when
-    reading an interlaced file, to avoid a possible UMR.
-  Undid revision of PNG_NO_STDIO version of png_write_flush().  Users
-    having trouble with fflush() can build with PNG_NO_WRITE_FLUSH defined
-    or supply their own flush_fn() replacement.
-  Revised libpng*.txt and png.h documentation about use of png_write_flush()
-    and png_set_write_fn().
-  Removed fflush() from pngtest.c.
-  Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
-
-Version 1.4.0beta51 [March 21, 2009]
-  Removed new png_fileno() macro from pngconf.h .
-
-Version 1.4.0beta52 [March 27, 2009]
-  Relocated png_do_chop() ahead of building gamma tables in pngrtran.c
-    This avoids building 16-bit gamma tables unnecessarily.
-  Removed fflush() from pngtest.c.
-  Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
-  Added a section on differences between 1.0.x and 1.2.x to libpng.3/libpng.txt
-
-Version 1.4.0beta53 [April 1, 2009]
-  Removed some remaining MMX macros from pngpriv.h
-  Fixed potential memory leak of "new_name" in png_write_iCCP() (Ralph Giles)
-
-Version 1.4.0beta54 [April 13, 2009]
-  Added "ifndef PNG_SKIP_SETJMP_CHECK" block in pngconf.h to allow
-    application code writers to bypass the check for multiple inclusion
-    of setjmp.h when they know that it is safe to ignore the situation.
-  Eliminated internal use of setjmp() in pngread.c and pngwrite.c
-  Reordered ancillary chunks in pngtest.png to be the same as what
-    pngtest now produces, and made some cosmetic changes to pngtest output.
-  Eliminated deprecated png_read_init_3() and png_write_init_3() functions.
-
-Version 1.4.0beta55 [April 15, 2009]
-  Simplified error handling in pngread.c and pngwrite.c by putting
-    the new png_read_cleanup() and png_write_cleanup() functions inline.
-
-Version 1.4.0beta56 [April 25, 2009]
-  Renamed "user_chunk_data" to "my_user_chunk_data" in pngtest.c to suppress
-    "shadowed declaration" warning from gcc-4.3.3.
-  Renamed "gamma" to "png_gamma" in pngset.c to avoid "shadowed declaration"
-    warning about a global "gamma" variable in math.h on some platforms.
-
-Version 1.4.0beta57 [May 2, 2009]
-  Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
-    but was never defined (again).
-  Rebuilt configure scripts with autoconf-2.63 instead of 2.62
-  Removed pngprefs.h and MMX from makefiles
-
-Version 1.4.0beta58 [May 14, 2009]
-  Changed pngw32.def to pngwin.def in makefile.mingw (typo was introduced
-    in beta57).
-  Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri)
-
-Version 1.4.0beta59 [May 15, 2009]
-  Reformated sources in libpng style (3-space intentation, comment format)
-  Fixed typo in libpng docs (PNG_FILTER_AVE should be PNG_FILTER_AVG)
-  Added sections about the git repository and our coding style to the
-    documentation
-  Relocated misplaced #endif in pngwrite.c, sCAL chunk handler.
-
-Version 1.4.0beta60 [May 19, 2009]
-  Conditionally compile png_read_finish_row() which is not used by
-    progressive readers.
-  Added contrib/pngminim/preader to demonstrate building minimal progressive
-    decoder, based on contrib/gregbook with embedded libpng and zlib.
-
-Version 1.4.0beta61 [May 20, 2009]
-  In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there
-    is only one makefile in those directories, and revised the README files
-    accordingly.
-  More reformatting of comments, mostly to capitalize sentences.
-
-Version 1.4.0beta62 [June 2, 2009]
-  Added "#define PNG_NO_WRITE_SWAP" to contrib/pngminim/encoder/pngusr.h
-    and "define PNG_NO_READ_SWAP" to decoder/pngusr.h and preader/pngusr.h
-  Reformatted several remaining "else statement" into two lines.
-  Added a section to the libpng documentation about using png_get_io_ptr()
-    in configure scripts to detect the presence of libpng.
-
-Version 1.4.0beta63 [June 15, 2009]
-  Revised libpng*.txt and libpng.3 to mention calling png_set_IHDR()
-    multiple times and to specify the sample order in the tRNS chunk,
-    because the ISO PNG specification has a typo in the tRNS table.
-  Changed several PNG_UNKNOWN_CHUNK_SUPPORTED to
-    PNG_HANDLE_AS_UNKNOWN_SUPPORTED, to make the png_set_keep mechanism
-    available for ignoring known chunks even when not saving unknown chunks.
-  Adopted preference for consistent use of "#ifdef" and "#ifndef" versus
-    "#if defined()" and "if !defined()" where possible.
-
-Version 1.4.0beta64 [June 24, 2009]
-  Eliminated PNG_LEGACY_SUPPORTED code.
-  Moved the various unknown chunk macro definitions outside of the
-     PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks.
-
-Version 1.4.0beta65 [June 26, 2009]
-  Added a reference to the libpng license in each file.
-
-Version 1.4.0beta66 [June 27, 2009]
-  Refer to the libpng license instead of the libpng license in each file.
-
-Version 1.4.0beta67 [July 6, 2009]
-  Relocated INVERT_ALPHA within png_read_png() and png_write_png().
-  Added high-level API transform PNG_TRANSFORM_GRAY_TO_RGB.
-  Added an "xcode" project to the projects directory (Alam Arias).
-
-Version 1.4.0beta68 [July 19, 2009]
-  Avoid some tests in filter selection in pngwutil.c
-
-Version 1.4.0beta69 [July 25, 2009]
-  Simplified the new filter-selection test.  This runs faster in the
-    common "PNG_ALL_FILTERS" and PNG_FILTER_NONE cases.
-  Removed extraneous declaration from the new call to png_read_gray_to_rgb()
-    (bug introduced in libpng-1.4.0beta67).
-  Fixed up xcode project (Alam Arias)
-  Added a prototype for png_64bit_product() in png.c
-
-Version 1.4.0beta70 [July 27, 2009]
-  Avoid a possible NULL dereference in debug build, in png_set_text_2().
-    (bug introduced in libpng-0.95, discovered by Evan Rouault)
-
-Version 1.4.0beta71 [July 29, 2009]
-  Rebuilt configure scripts with autoconf-2.64.
-
-Version 1.4.0beta72 [August 1, 2009]
-  Replaced *.tar.lzma with *.tar.xz in distribution.  Get the xz codec
-    from <http://tukaani.org/xz>.
-
-Version 1.4.0beta73 [August 1, 2009]
-  Reject attempt to write iCCP chunk with negative embedded profile length
-    (JD Chen) (CVE-2009-5063).
-
-Version 1.4.0beta74 [August 8, 2009]
-  Changed png_ptr and info_ptr member "trans" to "trans_alpha".
-
-Version 1.4.0beta75 [August 21, 2009]
-  Removed an extra png_debug() recently added to png_write_find_filter().
-  Fixed incorrect #ifdef in pngset.c regarding unknown chunk support.
-
-Version 1.4.0beta76 [August 22, 2009]
-  Moved an incorrectly located test in png_read_row() in pngread.c
-
-Version 1.4.0beta77 [August 27, 2009]
-  Removed lpXYZ.tar.bz2 (with CRLF), KNOWNBUG, libpng-x.y.z-KNOWNBUG.txt,
-    and the "noconfig" files from the distribution.
-  Moved CMakeLists.txt from scripts into the main libpng directory.
-  Various bugfixes and improvements to CMakeLists.txt (Philip Lowman)
-
-Version 1.4.0beta78 [August 31, 2009]
-  Converted all PNG_NO_* tests to PNG_*_SUPPORTED everywhere except pngconf.h
-  Eliminated PNG_NO_FREE_ME and PNG_FREE_ME_SUPPORTED macros.
-  Use png_malloc plus a loop instead of png_calloc() to initialize
-    row_pointers in png_read_png().
-
-Version 1.4.0beta79 [September 1, 2009]
-  Eliminated PNG_GLOBAL_ARRAYS and PNG_LOCAL_ARRAYS; always use local arrays.
-  Eliminated PNG_CALLOC_SUPPORTED macro and always provide png_calloc().
-
-Version 1.4.0beta80 [September 17, 2009]
-  Removed scripts/libpng.icc
-  Changed typecast of filler from png_byte to png_uint_16 in png_set_filler().
-    (Dennis Gustafsson)
-  Fixed typo introduced in beta78 in pngtest.c ("#if def " should be "#ifdef ")
-
-Version 1.4.0beta81 [September 23, 2009]
-  Eliminated unused PNG_FLAG_FREE_* defines from pngpriv.h
-  Expanded TAB characters in pngrtran.c
-  Removed PNG_CONST from all "PNG_CONST PNG_CHNK" declarations to avoid
-    compiler complaints about doubly declaring things "const".
-  Changed all "#if [!]defined(X)" to "if[n]def X" where possible.
-  Eliminated unused png_ptr->row_buf_size
-
-Version 1.4.0beta82 [September 25, 2009]
-  Moved redundant IHDR checking into new png_check_IHDR() in png.c
-    and report all errors found in the IHDR data.
-  Eliminated useless call to png_check_cHRM() from pngset.c
-
-Version 1.4.0beta83 [September 25, 2009]
-  Revised png_check_IHDR() to eliminate bogus complaint about filter_type.
-
-Version 1.4.0beta84 [September 30, 2009]
-  Fixed some inconsistent indentation in pngconf.h
-  Revised png_check_IHDR() to add a test for width variable less than 32-bit.
-
-Version 1.4.0beta85 [October 1, 2009]
-  Revised png_check_IHDR() again, to check info_ptr members instead of
-    the contents of the returned parameters.
-
-Version 1.4.0beta86 [October 9, 2009]
-  Updated the "xcode" project (Alam Arias).
-  Eliminated a shadowed declaration of "pp" in png_handle_sPLT().
-
-Version 1.4.0rc01 [October 19, 2009]
-  Trivial cosmetic changes.
-
-Version 1.4.0beta87 [October 30, 2009]
-  Moved version 1.4.0 back into beta.
-
-Version 1.4.0beta88 [October 30, 2009]
-  Revised libpng*.txt section about differences between 1.2.x and 1.4.0
-    because most of the new features have now been ported back to 1.2.41
-
-Version 1.4.0beta89 [November 1, 2009]
-  More bugfixes and improvements to CMakeLists.txt (Philip Lowman)
-  Removed a harmless extra png_set_invert_alpha() from pngwrite.c
-  Apply png_user_chunk_cache_max within png_decompress_chunk().
-  Merged libpng-1.2.41.txt with libpng-1.4.0.txt where appropriate.
-
-Version 1.4.0beta90 [November 2, 2009]
-  Removed all remaining WIN32_WCE #ifdefs except those involving the
-    time.h "tm" structure
-
-Version 1.4.0beta91 [November 3, 2009]
-  Updated scripts/pngw32.def and projects/wince/png32ce.def
-  Copied projects/wince/png32ce.def to the scripts directory.
-  Added scripts/makefile.wce
-  Patched ltmain.sh for wince support.
-  Added PNG_CONVERT_tIME_SUPPORTED macro.
-
-Version 1.4.0beta92 [November 4, 2009]
-  Make inclusion of time.h in pngconf.h depend on PNG_CONVERT_tIME_SUPPORTED
-  Make #define PNG_CONVERT_tIME_SUPPORTED depend on PNG_WRITE_tIME_SUPPORTED
-  Revised libpng*.txt to describe differences from 1.2.40 to 1.4.0 (instead
-    of differences from 1.2.41 to 1.4.0)
-
-Version 1.4.0beta93 [November 7, 2009]
-  Added PNG_DEPSTRUCT, PNG_DEPRECATED, PNG_USE_RESULT, PNG_NORETURN, and
-    PNG_ALLOCATED macros to detect deprecated direct access to the
-    png_struct or info_struct members and other deprecated usage in
-    applications (John Bowler).
-  Updated scripts/makefile* to add "-DPNG_CONFIGURE_LIBPNG" to CFLAGS,
-    to prevent warnings about direct access to png structs by libpng
-    functions while building libpng.  They need to be tested, especially
-    those using compilers other than gcc.
-  Updated projects/visualc6 and visualc71 with "/d PNG_CONFIGURE_LIBPNG".
-    They should work but still need to be updated to remove
-    references to pnggccrd.c or pngvcrd.c and ASM building.
-  Added README.txt to the beos, cbuilder5, netware, and xcode projects warning
-    that they need to be updated, to remove references to pnggccrd.c and
-    pngvcrd.c and to depend on pngpriv.h
-  Removed three direct references to read_info_ptr members in pngtest.c
-    that were detected by the new PNG_DEPSTRUCT macro.
-  Moved the png_debug macro definitions and the png_read_destroy(),
-    png_write_destroy() and png_far_to_near() prototypes from png.h
-    to pngpriv.h (John Bowler)
-  Moved the synopsis lines for png_read_destroy(), png_write_destroy()
-    png_debug(), png_debug1(), and png_debug2() from libpng.3 to libpngpf.3.
-
-Version 1.4.0beta94 [November 9, 2009]
-  Removed the obsolete, unused pnggccrd.c and pngvcrd.c files.
-  Updated CMakeLists.txt to add "-DPNG_CONFIGURE_LIBPNG" to the definitions.
-  Removed dependency of pngtest.o on pngpriv.h in the makefiles.
-  Only #define PNG_DEPSTRUCT, etc. in pngconf.h if not already defined.
-
-Version 1.4.0beta95 [November 10, 2009]
-  Changed png_check_sig() to !png_sig_cmp() in contrib programs.
-  Added -DPNG_CONFIGURE_LIBPNG to contrib/pngminm/*/makefile
-  Changed png_check_sig() to !png_sig_cmp() in contrib programs.
-  Corrected the png_get_IHDR() call in contrib/gregbook/readpng2.c
-  Changed pngminim/*/gather.sh to stop trying to remove pnggccrd.c and pngvcrd.c
-  Added dependency on pngpriv.h in contrib/pngminim/*/makefile
-
-Version 1.4.0beta96 [November 12, 2009]
-  Renamed scripts/makefile.wce to scripts/makefile.cegcc
-  Revised Makefile.am to use libpng.sys while building libpng.so
-    so that only PNG_EXPORT functions are exported.
-  Removed the deprecated png_check_sig() function/macro.
-  Removed recently removed function names from scripts/*.def
-  Revised pngtest.png to put chunks in the same order written by pngtest
-    (evidently the same change made in libpng-1.0beta54 was lost).
-  Added PNG_PRIVATE macro definition in pngconf.h for possible future use.
-
-Version 1.4.0beta97 [November 13, 2009]
-  Restored pngtest.png to the libpng-1.4.0beta7 version.
-  Removed projects/beos and netware.txt; no one seems to be supporting them.
-  Revised Makefile.in
-
-Version 1.4.0beta98 [November 13, 2009]
-  Added the "xcode" project to zip distributions,
-  Fixed a typo in scripts/pngwin.def introduced in beta97.
-
-Version 1.4.0beta99 [November 14, 2009]
-  Moved libpng-config.in and libpng.pc-configure.in out of the scripts
-    directory, to libpng-config.in and libpng-pc.in, respectively, and
-    modified Makefile.am and configure.ac accordingly.  Now "configure"
-    needs nothing from the "scripts" directory.
-  Avoid redefining PNG_CONST in pngconf.h
-
-Version 1.4.0beta100 [November 14, 2009]
-  Removed ASM builds from projects/visualc6 and projects/visualc71
-  Removed scripts/makefile.nommx and makefile.vcawin32
-  Revised CMakeLists.txt to account for new location of libpng-config.in
-    and libpng-pc.in
-  Updated INSTALL to reflect removal and relocation of files.
-
-Version 1.4.0beta101 [November 14, 2009]
-  Restored the binary files (*.jpg, *.png, some project files) that were
-    accidentally deleted from the zip and 7z distributions when the xcode
-    project was added.
-
-Version 1.4.0beta102 [November 18, 2009]
-  Added libpng-config.in and libpng-pc.in to the zip and 7z distributions.
-  Fixed a typo in projects/visualc6/pngtest.dsp, introduced in beta100.
-  Moved descriptions of makefiles and other scripts out of INSTALL into
-    scripts/README.txt
-  Updated the copyright year in scripts/pngwin.rc from 2006 to 2009.
-
-Version 1.4.0beta103 [November 21, 2009]
-  Removed obsolete comments about ASM from projects/visualc71/README_zlib.txt
-  Align row_buf on 16-byte boundary in memory.
-  Restored the PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED guard around the call
-    to png_flush() after png_write_IEND().  See 1.4.0beta32, 1.4.0beta50
-    changes above and 1.2.30, 1.2.30rc01 and rc03 in 1.2.41 CHANGES.  Someone
-    needs this feature.
-  Make the 'png_jmpbuf' macro expand to a call that records the correct
-    longjmp function as well as returning a pointer to the setjmp
-    jmp_buf buffer, and marked direct access to jmpbuf 'deprecated'.
-    (John Bowler)
-
-Version 1.4.0beta104 [November 22, 2009]
-  Removed png_longjmp_ptr from scripts/*.def and libpng.3
-  Rebuilt configure scripts with autoconf-2.65
-
-Version 1.4.0beta105 [November 25, 2009]
-  Use fast integer PNG_DIVIDE_BY_255() or PNG_DIVIDE_BY_65535()
-    to accomplish alpha premultiplication when
-    PNG_READ_COMPOSITE_NODIV_SUPPORTED is defined.
-  Changed "/255" to "/255.0" in background calculations to make it clear
-    that the 255 is used as a double.
-
-Version 1.4.0beta106 [November 27, 2009]
-  Removed premultiplied alpha feature.
-
-Version 1.4.0beta107 [December 4, 2009]
-  Updated README
-  Added "#define PNG_NO_PEDANTIC_WARNINGS" in the libpng source files.
-  Removed "-DPNG_CONFIGURE_LIBPNG" from the makefiles and projects.
-  Revised scripts/makefile.netbsd, makefile.openbsd, and makefile.sco
-    to put png.h and pngconf.h in $prefix/include, like the other scripts,
-    instead of in $prefix/include/libpng.  Also revised makefile.sco
-    to put them in $prefix/include/libpng15 instead of in
-    $prefix/include/libpng/libpng15.
-
-Version 1.4.0beta108 [December 11, 2009]
-  Removed leftover "-DPNG_CONFIGURE_LIBPNG" from contrib/pngminim/*/makefile
-  Relocated png_do_chop() to its original position in pngrtran.c; the
-    change in version 1.2.41beta08 caused transparency to be handled wrong
-    in some 16-bit datastreams (Yusaku Sugai).
-
-Version 1.4.0beta109 [December 13, 2009]
-  Added "bit_depth" parameter to the private png_build_gamma_table() function.
-  Pass bit_depth=8 to png_build_gamma_table() when bit_depth is 16 but the
-    PNG_16_TO_8 transform has been set, to avoid unnecessary build of 16-bit
-    tables.
-
-Version 1.4.0rc02 [December 20, 2009]
-  Declared png_cleanup_needed "volatile" in pngread.c and pngwrite.c
-
-Version 1.4.0rc03 [December 22, 2009]
-  Renamed libpng-pc.in back to libpng.pc.in and revised CMakeLists.txt
-    (revising the change in 1.4.0beta99)
-
-Version 1.4.0rc04 [December 25, 2009]
-  Swapped PNG_UNKNOWN_CHUNKS_SUPPORTED and PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-    in pngset.c to be consistent with other changes in version 1.2.38.
-
-Version 1.4.0rc05 [December 25, 2009]
-  Changed "libpng-pc.in" to "libpng.pc.in" in configure.ac, configure, and
-    Makefile.in to be consistent with changes in libpng-1.4.0rc03
-
-Version 1.4.0rc06 [December 29, 2009]
-  Reverted the gamma_table changes from libpng-1.4.0beta109.
-  Fixed some indentation errors.
-
-Version 1.4.0rc07 [January 1, 2010]
-  Revised libpng*.txt and libpng.3 about 1.2.x->1.4.x differences.
-  Use png_calloc() instead of png_malloc(); png_memset() in pngrutil.c
-  Update copyright year to 2010.
-
-Version 1.4.0rc08 [January 2, 2010]
-  Avoid deprecated references to png_ptr-io_ptr and png_ptr->error_ptr
-    in pngtest.c
-
-Version 1.4.0 [January 3, 2010]
-  No changes.
-
-Version 1.4.1beta01 [January 8, 2010]
-  Updated CMakeLists.txt for consistent indentation and to avoid an
-    unclosed if-statement warning (Philip Lowman).
-  Revised Makefile.am and Makefile.in to remove references to Y2KINFO,
-    KNOWNBUG, and libpng.la (Robert Schwebel).
-  Revised the makefiles to install the same files and symbolic
-    links as configure, except for libpng.la and libpng14.la.
-  Make png_set|get_compression_buffer_size() available even when
-    PNG_WRITE_SUPPORTED is not enabled.
-  Revised Makefile.am and Makefile.in to simplify their maintenance.
-  Revised scripts/makefile.linux to install a link to libpng14.so.14.1
-
-Version 1.4.1beta02 [January 9, 2010]
-  Revised the rest of the makefiles to install a link to libpng14.so.14.1
-
-Version 1.4.1beta03 [January 10, 2010]
-  Removed png_set_premultiply_alpha() from scripts/*.def
-
-Version 1.4.1rc01 [January 16, 2010]
-  No changes.
-
-Version 1.4.1beta04 [January 23, 2010]
-  Revised png_decompress_chunk() to improve speed and memory usage when
-    decoding large chunks.
-  Added png_set|get_chunk_malloc_max() functions.
-
-Version 1.4.1beta05 [January 26, 2010]
-  Relocated "int k" declaration in pngtest.c to minimize its scope.
-
-Version 1.4.1beta06 [January 28, 2010]
-  Revised png_decompress_chunk() to use a two-pass method suggested by
-    John Bowler.
-
-Version 1.4.1beta07 [February 6, 2010]
-  Folded some long lines in the source files.
-  Added defineable PNG_USER_CHUNK_CACHE_MAX, PNG_USER_CHUNK_MALLOC_MAX,
-    and a PNG_USER_LIMITS_SUPPORTED flag.
-  Eliminated use of png_ptr->irowbytes and reused the slot in png_ptr as
-    png_ptr->png_user_chunk_malloc_max.
-  Revised png_push_save_buffer() to do fewer but larger png_malloc() calls.
-
-Version 1.4.1beta08 [February 6, 2010]
-  Minor cleanup and updating of dates and copyright year.
-
-Version 1.5.0beta01 [February 7, 2010]
-  Moved declaration of png_struct into private pngstruct.h and png_info
-    into pnginfo.h
-
-Version 1.4.1beta09 and 1.5.0beta02 [February 7, 2010]
-  Reverted to original png_push_save_buffer() code.
-
-Version 1.4.1beta10 and 1.5.0beta03 [February 8, 2010]
-  Return allocated "old_buffer" in png_push_save_buffer() before
-    calling png_error(), to avoid a potential memory leak.
-  Updated configure script to use SO number 15.
-
-Version 1.5.0beta04 [February 9, 2010]
-  Removed malformed "incomplete struct declaration" of png_info from png.h
-
-Version 1.5.0beta05 [February 12, 2010]
-  Removed PNG_DEPSTRUCT markup in pngstruct.h and pnginfo.h, and undid the
-    linewrapping that it entailed.
-  Revised comments in pngstruct.h and pnginfo.h and added pointers to
-    the libpng license.
-  Changed PNG_INTERNAL to PNG_EXPOSE_INTERNAL_STRUCTURES
-  Removed the cbuilder5 project, which has not been updated to 1.4.0.
-
-Version 1.4.1beta12 and 1.5.0beta06 [February 14, 2010]
-  Fixed type declaration of png_get_chunk_malloc_max() in pngget.c (Daisuke
-    Nishikawa)
-
-Version 1.5.0beta07 [omitted]
-
-Version 1.5.0beta08 [February 19, 2010]
-  Changed #ifdef PNG_NO_STDIO_SUPPORTED to #ifdef PNG_NO_CONSOLE_IO_SUPPORTED
-    wherever png_snprintf() is used to construct error and warning messages.
-  Noted in scripts/makefile.mingw that it expects to be run under MSYS.
-  Removed obsolete unused MMX-querying support from contrib/gregbook
-  Added exported png_longjmp() function.
-  Removed the AIX redefinition of jmpbuf in png.h
-  Added -D_ALLSOURCE in configure.ac, makefile.aix, and CMakeLists.txt
-    when building on AIX.
-
-Version 1.5.0beta09 [February 19, 2010]
-  Removed -D_ALLSOURCE from configure.ac, makefile.aix, and CMakeLists.txt.
-  Changed the name of png_ptr->jmpbuf to png_ptr->png_jmpbuf in pngstruct.h
-
-Version 1.5.0beta10 [February 25, 2010]
-  Removed unused gzio.c from contrib/pngminim gather and makefile scripts
-  Removed replacement error handlers from contrib/gregbook.  Because of
-    the new png_longjmp() function they are no longer needed.
-
-Version 1.5.0beta11 [March 6, 2010]
-  Removed checking for already-included setjmp.h from pngconf.h
-  Fixed inconsistent indentations and made numerous cosmetic changes.
-  Revised the "SEE ALSO" style of libpng.3, libpngpf.3, and png.5
-
-Version 1.5.0beta12 [March 9, 2010]
-  Moved "#include png.h" inside pngpriv.h and removed "#include png.h" from
-    the source files, along with "#define PNG_EXPOSE_INTERNAL_STRUCTURES"
-    and "#define PNG_NO_PEDANTIC_WARNINGS" (John Bowler).
-  Created new pngdebug.h and moved debug definitions there.
-
-Version 1.5.0beta13 [March 10, 2010]
-  Protect pngstruct.h, pnginfo.h, and pngdebug.h from being included twice.
-  Revise the "#ifdef" blocks in png_inflate() so it will compile when neither
-    PNG_USER_CHUNK_MALLOC_MAX nor PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
-    is defined.
-  Removed unused png_measure_compressed_chunk() from pngpriv.h and libpngpf.3
-  Moved the 'config.h' support from pngconf.h to pngpriv.h
-  Removed PNGAPI from the png_longjmp_ptr typedef.
-  Eliminated dependence of pngtest.c on the private pngdebug.h file.
-  Make all png_debug macros into *unterminated* statements or
-    expressions (i.e. a trailing ';' must always be added) and correct
-    the format statements in various png_debug messages.
-
-Version 1.5.0beta14 [March 14, 2010]
-  Removed direct access to png_ptr->io_ptr from the Windows code in pngtest.c
-  Revised Makefile.am to account for recent additions and replacements.
-  Corrected CE and OS/2 DEF files (scripts/png*def) for symbols removed and
-    added ordinal numbers to the Windows DEF file and corrected the duplicated
-    ordinal numbers on CE symbols that are commented out.
-  Added back in export symbols that can be present in the Windows build but
-    are disabled by default.
-  PNG_EXPORT changed to include an 'ordinal' field for DEF file generation.
-    PNG_CALLBACK added to make callback definitions uniform.  PNGAPI split
-    into PNGCAPI (base C form), PNGAPI (exports) and PNGCBAPI (callbacks),
-    and appropriate changes made to all files.  Cygwin builds re-hinged to
-    allow procedure call standard changes and to remove the need for the DEF
-    file (fixes build on Cygwin).
-  Enabled 'attribute' warnings that are relevant to library APIs and callbacks.
-  Changed rules for generation of the various symbol files and added a new
-    rule for a DEF file (which is also added to the distribution).
-  Updated the symbol file generation to stop it adding spurious spaces
-    to EOL (coming from preprocessor macro expansion).  Added a facility
-    to join tokens in the output and rewrite *.dfn to use this.
-  Eliminated scripts/*.def in favor of libpng.def; updated projects/visualc71
-    and removed scripts/makefile.cygwin.
-  Made PNG_BUILD_DLL safe: it can be set whenever a DLL is being built.
-  Removed the include of sys/types.h - apparently unnecessary now on the
-    platforms on which it happened (all but Mac OS and RISC OS).
-  Moved the Mac OS test into pngpriv.h (the only place it is used.)
-
-Version 1.5.0beta15 [March 17, 2010]
-  Added symbols.chk target to Makefile.am to validate the symbols in png.h
-    against the new DEF file scripts/symbols.def.
-  Changed the default DEF file back to pngwin.def.
-  Removed makefile.mingw.
-  Eliminated PNG_NO_EXTERN and PNG_ALL_EXTERN
-
-Version 1.5.0beta16 [April 1, 2010]
-  Make png_text_struct independent of PNG_iTXt_SUPPORTED, so that
-    fields are initialized in all configurations.  The READ/WRITE
-    macros (PNG_(READ|WRITE)_iTXt_SUPPORTED) still function as
-    before to disable code to actually read or write iTXt chunks
-    and iTXt_SUPPORTED can be used to detect presence of either
-    read or write support (but it is probably better to check for
-    the one actually required - read or write.)
-  Combined multiple png_warning() calls for a single error.
-  Restored the macro definition of png_check_sig().
-
-Version 1.5.0beta17 [April 17, 2010]
-  Added some "(long)" typecasts to printf calls in png_handle_cHRM().
-  Documented the fact that png_set_dither() was disabled since libpng-1.4.0.
-  Reenabled png_set_dither() but renamed it to png_set_quantize() to reflect
-    more accurately what it actually does.  At the same time, renamed
-    the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros to
-    PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS.
-  Added some "(long)" typecasts to printf calls in png_handle_cHRM().
-  Freeze build-time only configuration in the build.
-    In all prior versions of libpng most configuration options
-    controlled by compiler #defines had to be repeated by the
-    application code that used libpng.  This patch changes this
-    so that compilation options that can only be changed at build
-    time are frozen in the build.  Options that are compiler
-    dependent (and those that are system dependent) are evaluated
-    each time - pngconf.h holds these.  Options that can be changed
-    per-file in the application are in png.h.  Frozen options are
-    in the new installed header file pnglibconf.h (John Bowler)
-  Removed the xcode project because it has not been updated to work
-    with libpng-1.5.0.
-  Removed the ability to include optional pngusr.h
-
-Version 1.5.0beta18 [April 17, 2010]
-  Restored the ability to include optional pngusr.h
-  Moved replacements for png_error() and png_warning() from the
-    contrib/pngminim project to pngerror.c, for use when warnings or
-    errors are disabled via PNG_NO_WARN or PNG_NO_ERROR_TEXT, to avoid
-    storing unneeded error/warning text.
-  Updated contrib/pngminim project to work with the new pnglibconf.h
-  Added some PNG_NO_* defines to contrib/pngminim/*/pngusr.h to save space.
-
-Version 1.5.0beta19 [April 24, 2010]
-  Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the functions
-    to read and write ints to be disabled independently of PNG_USE_READ_MACROS,
-    which allows libpng to be built with the functions even though the default
-    is to use the macros - this allows applications to choose at app build
-    time whether or not to use macros (previously impossible because the
-    functions weren't in the default build.)
-  Changed Windows calling convention back to __cdecl for API functions.
-    For Windows/x86 platforms only:
-      __stdcall is no longer needed for Visual Basic, so libpng-1.5.0 uses
-      __cdecl throughout (both API functions and callbacks) on Windows/x86
-      platforms.
-  Replaced visualc6 and visualc71 projects with new vstudio project
-  Relaxed the overly-restrictive permissions of some files.
-
-Version 1.5.0beta20 [April 24, 2010]
-  Relaxed more overly-restrictive permissions of some files.
-
-Version 1.5.0beta21 [April 27, 2010]
-  Removed some unwanted binary bytes and changed CRLF to NEWLINE in the new
-    vstudio project files, and some trivial editing of some files in the
-    scripts directory.
-  Set PNG_NO_READ_BGR, PNG_NO_IO_STATE, and PNG_NO_TIME_RFC1123 in
-    contrib/pngminim/decoder/pngusr.h to make a smaller decoder application.
-
-Version 1.5.0beta22 [April 28, 2010]
-  Fixed dependencies of GET_INT_32 - it does not require READ_INT_FUNCTIONS
-    because it has a macro equivalent.
-  Improved the options.awk script; added an "everything off" option.
-  Revised contrib/pngminim to use the "everything off" option in pngusr.dfa.
-
-Version 1.5.0beta23 [April 29, 2010]
-  Corrected PNG_REMOVED macro to take five arguments.
-    The macro was documented with two arguments (name,ordinal), however
-    the symbol checking .dfn files assumed five arguments.  The five
-    argument form seems more useful so it is changed to that.
-  Corrected PNG_UNKNOWN_CHUNKS_SUPPORTED to PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-    in gregbook/readpng2.c
-  Corrected protection of png_get_user_transform_ptr. The API declaration in
-    png.h is removed if both READ and WRITE USER_TRANSFORM are turned off
-    but was left defined in pngtrans.c
-  Added logunsupported=1 to cause pnglibconf.h to document disabled options.
-    This makes the installed pnglibconf.h more readable but causes no
-    other change.  The intention is that users of libpng will find it
-    easier to understand if an API they need is missing.
-  Include png_reset_zstream() in png.c only when PNG_READ_SUPPORTED is defined.
-  Removed dummy_inflate.c from contrib/pngminim/encoder
-  Removed contrib/pngminim/*/gather.sh; gathering is now done in the makefile.
-
-Version 1.5.0beta24 [May 7, 2010]
-  Use bitwise "&" instead of arithmetic mod in pngrutil.c calculation of the
-    offset of the png_ptr->rowbuf pointer into png_ptr->big_row_buf.
-  Added more blank lines for readability.
-
-Version 1.5.0beta25 [June 18, 2010]
-  In pngpread.c: png_push_have_row() add check for new_row > height
-  Removed the now-redundant check for out-of-bounds new_row from example.c
-
-Version 1.5.0beta26 [June 18, 2010]
-  In pngpread.c: png_push_process_row() add check for too many rows.
-
-Version 1.5.0beta27 [June 18, 2010]
-  Removed the check added in beta25 as it is now redundant.
-
-Version 1.5.0beta28 [June 20, 2010]
-  Rewrote png_process_IDAT_data to consistently treat extra data as warnings
-    and handle end conditions more cleanly.
-  Removed the new (beta26) check in png_push_process_row().
-
-Version 1.5.0beta29 [June 21, 2010]
-  Revised scripts/options.awk to work on Sunos (but still doesn't work)
-  Added comment to options.awk and contrib/pngminim/*/makefile to try nawk.
-
-Version 1.5.0beta30 [June 22, 2010]
-  Stop memory leak when reading a malformed sCAL chunk.
-
-Version 1.5.0beta31 [June 26, 2010]
-  Revised pngpread.c patch of beta28 to avoid an endless loop.
-  Removed some trailing blanks.
-
-Version 1.5.0beta32 [June 26, 2010]
-  Removed leftover scripts/options.patch and scripts/options.rej
-
-Version 1.5.0beta33 [July 6, 3010]
-  Made FIXED and FLOATING options consistent in the APIs they enable and
-    disable.  Corrected scripts/options.awk to handle both command line
-    options and options specified in the .dfa files.
-  Changed char *msg to PNG_CONST char *msg in pngrutil.c
-  Make png_set_sRGB_gAMA_and_cHRM set values using either the fixed or
-    floating point APIs, but not both.
-  Reversed patch to remove error handler when the jmp_buf is stored in the
-    main program structure, not the png_struct.
-    The error handler is needed because the default handler in libpng will
-    always use the jmp_buf in the library control structure; this is never
-    set.  The gregbook code is a useful example because, even though it
-    uses setjmp/longjmp, it shows how error handling can be implemented
-    using control mechanisms not directly supported by libpng.  The
-    technique will work correctly with mechanisms such as Microsoft
-    Structure Exceptions or C++ exceptions (compiler willing - note that gcc
-    does not by default support interworking of C and C++ error handling.)
-  Reverted changes to call png_longjmp in contrib/gregbook where it is not
-    appropriate.  If mainprog->jmpbuf is used by setjmp, then png_longjmp
-    cannot be used.
-  Changed "extern PNG_EXPORT" to "PNG_EXPORT" in png.h (Jan Nijtmans)
-  Changed "extern" to "PNG_EXTERN" in pngpriv.h (except for the 'extern "C" {')
-
-Version 1.5.0beta34 [July 12, 2010]
-  Put #ifndef PNG_EXTERN, #endif around the define PNG_EXTERN in pngpriv.h
-
-Version 1.5.0beta35 [July 24, 2010]
-  Removed some newly-added TAB characters.
-  Added -DNO_PNG_SNPRINTF to CFLAGS in scripts/makefile.dj2
-  Moved the definition of png_snprintf() outside of the enclosing
-    #ifdef blocks in pngconf.h
-
-Version 1.5.0beta36 [July 29, 2010]
-  Patches by John Bowler:
-  Fixed point APIs are now supported throughout (no missing APIs).
-  Internal fixed point arithmetic support exists for all internal floating
-    point operations.
-  sCAL validates the floating point strings it is passed.
-  Safe, albeit rudimentary, Watcom support is provided by PNG_API_RULE==2
-  Two new APIs exist to get the number of passes without turning on the
-    PNG_INTERLACE transform and to get the number of rows in the current
-    pass.
-  A new test program, pngvalid.c, validates the gamma code.
-  Errors in the 16-bit gamma correction (overflows) have been corrected.
-  cHRM chunk testing is done consistently (previously the floating point
-    API bypassed it, because the test really didn't work on FP, now the test
-    is performed on the actual values to be stored in the PNG file so it
-    works in the FP case too.)
-  Most floating point APIs now simply call the fixed point APIs after
-    converting the values to the fixed point form used in the PNG file.
-  The standard headers no longer include zlib.h, which is currently only
-    required for pngstruct.h and can therefore be internal.
-  Revised png_get_int_32 to undo the PNG two's complement representation of
-    negative numbers.
-
-Version 1.5.0beta37 [July 30, 2010]
-  Added a typecast in png_get_int_32() in png.h and pngrutil.h to avoid
-    a compiler warning.
-  Replaced oFFs 0,0 with oFFs -10,20 in pngtest.png
-
-Version 1.5.0beta38 [July 31, 2010]
-  Implemented remaining "_fixed" functions.
-  Corrected a number of recently introduced warnings mostly resulting from
-    safe but uncast assignments to shorter integers.  Also added a zlib
-    VStudio release library project because the latest zlib Official Windows
-    build does not include such a thing.
-  Revised png_get_int_16() to be similar to png_get_int_32().
-  Restored projects/visualc71.
-
-Version 1.5.0beta39 [August 2, 2010]
-  VisualC/GCC warning fixes, VisualC build fixes
-  The changes include support for function attributes in VC in addition to
-    those already present in GCC - necessary because without these some
-    warnings are unavoidable.  Fixes include signed/unsigned fixes in
-    pngvalid and checks with gcc -Wall -Wextra -Wunused.
-  VC requires function attributes on function definitions as well as
-    declarations, PNG_FUNCTION has been added to enable this and the
-    relevant function definitions changed.
-
-Version 1.5.0beta40 [August 6, 2010]
-  Correct use of _WINDOWS_ in pngconf.h
-  Removed png_mem_ #defines; they are no longer used.
-  Added the sRGB chunk to pngtest.png
-
-Version 1.5.0beta41 [August 11, 2010]
-  Added the cHRM chunk to pngtest.png
-  Don't try to use version-script with cygwin/mingw.
-  Revised contrib/gregbook to work under cygwin/mingw.
-
-Version 1.5.0beta42 [August 18, 2010]
-  Add .dll.a to the list of extensions to be symlinked by Makefile.am (Yaakov)
-  Made all API functions that have const arguments and constant string
-    literal pointers declare them (John Bowler).
-
-Version 1.5.0beta43 [August 20, 2010]
-  Removed spurious tabs, shorten long lines (no source change)
-    Also added scripts/chkfmt to validate the format of all the files that can
-    reasonably be validated (it is suggested to run "make distclean" before
-    checking, because some machine generated files have long lines.)
-  Reformatted the CHANGES file to be more consistent throughout.
-  Made changes to address various issues identified by GCC, mostly
-    signed/unsigned and shortening problems on assignment but also a few
-    difficult to optimize (for GCC) loops.
-  Fixed non-GCC fixed point builds.  In png.c a declaration was misplaced
-    in an earlier update.  Fixed to declare the auto variables at the head.
-  Use cexcept.h in pngvalid.c.
-
-Version 1.5.0beta44 [August 24, 2010]
-  Updated CMakeLists.txt to use CMAKE_INSTALL_LIBDIR variable; useful for
-    installing libpng in /usr/lib64 (Funda Wang).
-  Revised CMakeLists.txt to put the man pages in share/man/man* not man/man*
-  Revised CMakeLists.txt to make symlinks instead of copies when installing.
-  Changed PNG_LIB_NAME from pngNN to libpngNN in CMakeLists.txt (Philip Lowman)
-  Implemented memory checks within pngvalid
-  Reformatted/rearranged pngvalid.c to assist use of progressive reader.
-  Check interlaced images in pngvalid
-  Clarified pngusr.h comments in pnglibconf.dfa
-  Simplified the pngvalid error-handling code now that cexcept.h is in place.
-  Implemented progressive reader in pngvalid.c for standard tests
-  Implemented progressive read in pngvalid.c gamma tests
-  Turn on progressive reader in pngvalid.c by default and tidy code.
-
-Version 1.5.0beta45 [August 26, 2010]
-  Added an explicit make step to projects/vstudio for pnglibconf.h
-    Also corrected zlib.vcxproj into which Visual Studio had introduced
-    what it calls an "authoring error".  The change to make pnglibconf.h
-    simply copies the file; in the future it may actually generate the
-    file from scripts/pnglibconf.dfa as the other build systems do.
-  Changed pngvalid to work when floating point APIs are disabled
-  Renamed the prebuilt scripts/pnglibconf.h to scripts/pnglibconf.h.prebuilt
-  Supply default values for PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX
-    in pngpriv.h in case the user neglected to define them in their pngusr.h
-
-Version 1.5.0beta46 [August 28, 2010]
-  Added new private header files to libpng_sources in CMakeLists.txt
-  Added PNG_READ_16BIT, PNG_WRITE_16BIT, and PNG_16BIT options.
-  Added reference to scripts/pnglibconf.h.prebuilt in the visualc71 project.
-
-Version 1.5.0beta47 [September 11, 2010]
-  Fixed a number of problems with 64-bit compilation reported by Visual
-    Studio 2010 (John Bowler).
-
-Version 1.5.0beta48 [October 4, 2010]
-  Updated CMakeLists.txt (Philip Lowman).
-  Revised autogen.sh to recognize and use $AUTOCONF, $AUTOMAKE, $AUTOHEADER,
-    $AUTOPOINT, $ACLOCAL and $LIBTOOLIZE
-  Fixed problem with symbols creation in Makefile.am which was assuming that
-    all versions of ccp write to standard output by default (Martin Banky). The
-    bug was introduced in libpng-1.2.9beta5.
-  Removed unused mkinstalldirs.
-
-Version 1.5.0beta49 [October 8, 2010]
-  Undid Makefile.am revision of 1.5.0beta48.
-
-Version 1.5.0beta50 [October 14, 2010]
-  Revised Makefile.in to account for mkinstalldirs being removed.
-  Added some "(unsigned long)" typecasts in printf statements in pngvalid.c.
-  Suppressed a compiler warning in png_handle_sPLT().
-  Check for out-of-range text compression mode in png_set_text().
-
-Version 1.5.0beta51 [October 15, 2010]
-  Changed embedded dates to "(PENDING RELEASE) in beta releases (and future
-    rc releases) to minimize the difference between releases.
-
-Version 1.5.0beta52 [October 16, 2010]
-  Restored some of the embedded dates (in png.h, png.c, documentation, etc.)
-
-Version 1.5.0beta53 [October 18, 2010]
-  Updated INSTALL to mention using "make maintainer-clean" and to remove
-    obsolete statement about a custom ltmain.sh
-  Disabled "color-tests" by default in Makefile.am so it will work with
-    automake versions earlier than 1.11.1
-  Use document name "libpng-manual.txt" instead of "libpng-<version>.txt"
-    to simplify version differences.
-  Removed obsolete remarks about setjmp handling from INSTALL.
-  Revised and renamed the typedef in png.h and png.c that was designed
-    to catch library and header mismatch.
-
-Version 1.5.0beta54 [November 10, 2010]
-  Require 48 bytes, not 64 bytes, for big_row_buf in overflow checks.
-  Used a consistent structure for the pngget.c functions.
-
-Version 1.5.0beta55 [November 21, 2010]
-  Revised png_get_uint_32, png_get_int_32, png_get_uint_16 (Cosmin)
-  Moved reading of file signature into png_read_sig (Cosmin)
-  Fixed atomicity of chunk header serialization (Cosmin)
-  Added test for io_state in pngtest.c (Cosmin)
-  Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts.
-  Changes to remove gcc warnings (John Bowler)
-    Certain optional gcc warning flags resulted in warnings in libpng code.
-    With these changes only -Wconversion and -Wcast-qual cannot be turned on.
-    Changes are trivial rearrangements of code.  -Wconversion is not possible
-    for pngrutil.c (because of the widespread use of += et al on variables
-    smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
-    with pngwio.c and pngwutil.c because the 'write' callback and zlib
-    compression both fail to declare their input buffers with 'const'.
-
-Version 1.5.0beta56 [December 7, 2010]
-  Added the private PNG_UNUSED() macro definition in pngpriv.h.
-  Added some commentary about PNG_EXPORT in png.h and pngconf.h
-  Revised PNG_EXPORT() macro and added PNG_EXPORTA() macro, with the
-    objective of simplifying and improving the cosmetic appearance of png.h.
-  Fixed some incorrect "=" macro names in pnglibconf.dfa
-  Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt
-
-Version 1.5.0beta57 [December 9, 2010]
-  Documented the pngvalid gamma error summary with additional comments and
-    print statements.
-  Improved missing symbol handling in checksym.awk; symbols missing in both
-    the old and new files can now be optionally ignored, treated as errors
-    or warnings.
-  Removed references to pngvcrd.c and pnggccrd.c from the vstudio project.
-  Updated "libpng14" to "libpng15" in the visualc71 project.
-  Enabled the strip16 tests in pngvalid.`
-  Don't display test results (except PASS/FAIL) when running "make test".
-    Instead put them in pngtest-log.txt
-  Added "--with-zprefix=<string>" to configure.ac
-  Updated the prebuilt configuration files to autoconf version 2.68
-
-Version 1.5.0beta58 [December 19, 2010]
-  Fixed interlace image handling and add test cases (John Bowler)
-  Fixed the clean rule in Makefile.am to remove pngtest-log.txt
-  Made minor changes to work around warnings in gcc 3.4
-
-Version 1.5.0rc01 [December 27, 2010]
-  No changes.
-
-Version 1.5.0rc02 [December 27, 2010]
-  Eliminated references to the scripts/*.def files in project/visualc71.
-
-Version 1.5.0rc03 [December 28, 2010]
-  Eliminated scripts/*.def and revised Makefile.am accordingly
-
-Version 1.5.0rc04 [December 29, 2010]
-  Fixed bug in background transformation handling in pngrtran.c (it was
-    looking for the flag in png_ptr->transformations instead of in
-    png_ptr->flags) (David Raymond).
-
-Version 1.5.0rc05 [December 31, 2010]
-  Fixed typo in a comment in CMakeLists.txt (libpng14 => libpng15) (Cosmin)
-
-Version 1.5.0rc06 [January 4, 2011]
-  Changed the new configure option "zprefix=string" to "zlib-prefix=string"
-
-Version 1.5.0rc07 [January 4, 2011]
-  Updated copyright year.
-
-Version 1.5.0 [January 6, 2011]
-  No changes.
-
-version 1.5.1beta01 [January 8, 2011]
-  Added description of png_set_crc_action() to the manual.
-  Added a note in the manual that the type of the iCCP profile was changed
-    from png_charpp to png_bytepp in png_get_iCCP().  This change happened
-    in version 1.5.0beta36 but is not noted in the CHANGES.  Similarly,
-    it was changed from png_charpp to png_const_bytepp in png_set_iCCP().
-  Ensure that png_rgb_to_gray ignores palette mapped images, if libpng
-    internally happens to call it with one, and fixed a failure to handle
-    palette mapped images correctly.  This fixes CVE-2690.
-
-Version 1.5.1beta02 [January 14, 2011]
-  Fixed a bug in handling of interlaced images (bero at arklinux.org).
-  Updated CMakeLists.txt (Clifford Yapp)
-
-Version 1.5.1beta03 [January 14, 2011]
-  Fixed typecasting of some png_debug() statements (Cosmin)
-
-Version 1.5.1beta04 [January 16, 2011]
-  Updated documentation of png_set|get_tRNS() (Thomas Klausner).
-  Mentioned in the documentation that applications must #include "zlib.h"
-    if they need access to anything in zlib.h, and that a number of
-    macros such as png_memset() are no longer accessible by applications.
-  Corrected pngvalid gamma test "sample" function to access all of the color
-    samples of each pixel, instead of sampling the red channel three times.
-  Prefixed variable names index, div, exp, gamma with "png_" to avoid "shadow"
-    warnings, and (mistakenly) changed png_exp() to exp().
-
-Version 1.5.1beta05 [January 16, 2011]
-  Changed variable names png_index, png_div, png_exp, and png_gamma to
-    char_index, divisor, exp_b10, and gamma_val, respectively, and
-    changed exp() back to png_exp().
-
-Version 1.5.1beta06 [January 20, 2011]
-  Prevent png_push_crc_skip() from hanging while reading an unknown chunk
-    or an over-large compressed zTXt chunk with the progressive reader.
-  Eliminated more GCC "shadow" warnings.
-  Revised png_fixed() in png.c to avoid compiler warning about reaching the
-    end without returning anything.
-
-Version 1.5.1beta07 [January 22, 2011]
-  In the manual, describe the png_get_IHDR() arguments in the correct order.
-  Added const_png_structp and const_png_infop types, and used them in
-    prototypes for most png_get_*() functions.
-
-Version 1.5.1beta08 [January 23, 2011]
-  Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name()
-  Added synopses for the IO_STATE functions and other missing synopses
-    to the manual. Removed the synopses from libpngpf.3 because they
-    were out of date and no longer useful.  Better information can be
-    obtained by reading the prototypes and comments in pngpriv.h
-  Attempted to fix cpp on Solaris with S. Studio 12 cc, fix build
-    Added a make macro DFNCPP that is a CPP that will accept the tokens in
-    a .dfn file and adds configure stuff to test for such a CPP.  ./configure
-    should fail if one is not available.
-  Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace.
-  Added png_get_current_row_number and png_get_current_pass_number for the
-    benefit of the user transform callback.
-  Added png_process_data_pause and png_process_data_skip for the benefit of
-    progressive readers that need to stop data processing or want to optimize
-    skipping of unread data (e.g., if the reader marks a chunk to be skipped.)
-
-Version 1.5.1beta09 [January 24, 2011]
-  Enhanced pngvalid, corrected an error in gray_to_rgb, corrected doc error.
-    pngvalid contains tests of transforms, which tests are currently disabled
-    because they are incompletely tested.  gray_to_rgb was failing to expand
-    the bit depth for smaller bit depth images; this seems to be a long
-    standing error and resulted, apparently, in invalid output
-    (CVE-2011-0408, CERT VU#643140).  The documentation did not accurately
-    describe what libpng really does when converting RGB to gray.
-
-Version 1.5.1beta10 [January 27, 2010]
-  Fixed incorrect examples of callback prototypes in the manual, that were
-    introduced in libpng-1.0.0.
-  In addition the order of the png_get_uint macros with respect to the
-    relevant function definitions has been reversed.  This helps the
-    preprocessing of the symbol files be more robust.  Furthermore, the
-    symbol file preprocessing now uses -DPNG_NO_USE_READ_MACROS even when
-    the library may actually be built with PNG_USE_READ_MACROS; this stops
-    the read macros interfering with the symbol file format.
-  Made the manual, synopses, and function prototypes use the function
-    argument names file_gamma, int_file_gamma, and srgb_intent consistently.
-
-Version 1.5.1beta11 [January 28, 2011]
-  Changed PNG_UNUSED from "param=param;" to "{if(param){}}".
-  Corrected local variable type in new API png_process_data_skip()
-    The type was self-evidently incorrect but only causes problems on 64-bit
-    architectures.
-  Added transform tests to pngvalid and simplified the arguments.
-
-Version 1.5.1rc01 [January 29, 2011]
-  No changes.
-
-Version 1.5.1rc02 [January 31, 2011]
-  Added a request in the manual that applications do not use "png_" or
-    "PNG_" to begin any of their own symbols.
-  Changed PNG_UNUSED to "(void)param;" and updated the commentary in pngpriv.h
-
-Version 1.5.1 [February 3, 2011]
-  No changes.
-
-Version 1.5.2beta01 [February 13, 2011]
-  More -Wshadow fixes for older gcc compilers.  Older gcc versions apparently
-    check formal parameters names in function declarations (as well as
-    definitions) to see if they match a name in the global namespace.
-  Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the
-    old VisualC++ preprocessor.
-  Turned on interlace handling in png_read_png().
-  Fixed gcc pendantic warnings.
-  Handle longjmp in Cygwin.
-  Fixed png_get_current_row_number() in the interlaced case.
-  Cleaned up ALPHA flags and transformations.
-  Implemented expansion to 16 bits.
-
-Version 1.5.2beta02 [February 19, 2011]
-  Fixed mistake in the descriptions of user read_transform and write_transform
-    function prototypes in the manual.  The row_info struct is png_row_infop.
-  Reverted png_get_current_row_number() to previous (1.5.2beta01) behavior.
-  Corrected png_get_current_row_number documentation
-  Fixed the read/write row callback documentation.
-    This documents the current behavior, where the callback is called after
-    every row with information pertaining to the next row.
-
-Version 1.5.2beta03 [March 3, 2011]
-  Fixed scripts/makefile.vcwin32
-  Updated contrib/pngsuite/README to add the word "modify".
-  Define PNG_ALLOCATED to blank when _MSC_VER<1300.
-
-Version 1.5.2rc01 [March 19, 2011]
-  Define remaining attributes to blank when MSC_VER<1300.
-  ifdef out mask arrays in pngread.c when interlacing is not supported.
-
-Version 1.5.2rc02 [March 22, 2011]
-  Added a hint to try CPP=/bin/cpp if "cpp -E" fails in scripts/pnglibconf.mak
-    and in contrib/pngminim/*/makefile, eg., on SunOS 5.10, and removed "strip"
-    from the makefiles.
-  Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail
-    to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill)
-
-Version 1.5.2rc03 [March 24, 2011]
-  Don't include standard header files in png.h while building the symbol table,
-    to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro).
-
-Version 1.5.2 [March 31, 2011]
-  No changes.
-
-Version 1.5.3beta01 [April 1, 2011]
-  Re-initialize the zlib compressor before compressing non-IDAT chunks.
-  Added API functions (png_set_text_compression_level() and four others) to
-    set parameters for zlib compression of non-IDAT chunks.
-
-Version 1.5.3beta02 [April 3, 2011]
-  Updated scripts/symbols.def with new API functions.
-  Only compile the new zlib re-initializing code when text or iCCP is
-    supported, using PNG_WRITE_COMPRESSED_TEXT_SUPPORTED macro.
-  Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03).
-  Optimize the zlib CMF byte in non-IDAT compressed chunks
-
-Version 1.5.3beta03 [April 16, 2011]
-  Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
-    snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
-    than __STDC__ (John Bowler).
-  Removed the PNG_PTR_NORETURN attribute because it too dangerous. It tells
-    the compiler that a user supplied callback (the error handler) does not
-    return, yet there is no guarantee in practice that the application code
-    will correctly implement the error handler because the compiler only
-    issues a warning if there is a mistake (John Bowler).
-  Removed the no-longer-used PNG_DEPSTRUCT macro.
-  Updated the zlib version to 1.2.5 in the VStudio project.
-  Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
-    pngwutil.c (John Bowler).
-  Fixed bug with stripping the filler or alpha channel when writing, that
-    was introduced in libpng-1.5.2beta01 (bug report by Andrew Church).
-
-Version 1.5.3beta04 [April 27, 2011]
-  Updated pngtest.png with the new zlib CMF optimization.
-  Cleaned up conditional compilation code and of background/gamma handling
-    Internal changes only except a new option to avoid compiling the
-    png_build_grayscale_palette API (which is not used at all internally.)
-    The main change is to move the transform tests (READ_TRANSFORMS,
-    WRITE_TRANSFORMS) up one level to the caller of the APIs.  This avoids
-    calls to spurious functions if all transforms are disabled and slightly
-    simplifies those functions.  Pngvalid modified to handle this.
-    A minor change is to stop the strip_16 and expand_16 interfaces from
-    disabling each other; this allows the future alpha premultiplication
-    code to use 16-bit intermediate values while still producing 8-bit output.
-    png_do_background and png_do_gamma have been simplified to take a single
-    pointer to the png_struct rather than pointers to every item required
-    from the png_struct. This makes no practical difference to the internal
-    code.
-  A serious bug in the pngvalid internal routine 'standard_display_init' has
-    been fixed - this failed to initialize the red channel and accidentally
-    initialized the alpha channel twice.
-  Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
-    avoid a possible clash with the png_jmpbuf macro on some platforms.
-
-Version 1.5.3beta05 [May 6, 2011]
-  Added the "_POSIX_SOURCE" feature test macro to ensure libpng sees the
-    correct API. _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and
-    pngvalid.c to ensure that POSIX conformant systems disable non-POSIX APIs.
-  Removed png_snprintf and added formatted warning messages.  This change adds
-    internal APIs to allow png_warning messages to have parameters without
-    requiring the host OS to implement snprintf.  As a side effect the
-    dependency of the tIME-supporting RFC1132 code on stdio is removed and
-    PNG_NO_WARNINGS does actually work now.
-  Pass "" instead of '\0' to png_default_error() in png_err().  This mistake
-    was introduced in libpng-1.2.20beta01.  This fixes CVE-2011-2691.
-  Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
-    optimization configureable.
-  IDAT compression failed if preceded by a compressed text chunk (bug
-    introduced in libpng-1.5.3beta01-02).  This was because the attempt to
-    reset the zlib stream in png_write_IDAT happened after the first IDAT
-    chunk had been deflated - much too late.  In this change internal
-    functions were added to claim/release the z_stream and, hopefully, make
-    the code more robust.  Also deflateEnd checking is added - previously
-    libpng would ignore an error at the end of the stream.
-
-Version 1.5.3beta06 [May 8, 2011]
-  Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
-  Implemented premultiplied alpha support: png_set_alpha_mode API
-
-Version 1.5.3beta07 [May 11, 2011]
-  Added expand_16 support to the high level interface.
-  Added named value and 'flag' gamma support to png_set_gamma.  Made a minor
-    change from the previous (unreleased) ABI/API to hide the exact value used
-    for Macs - it's not a good idea to embed this in the ABI!
-  Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
-    from pngpriv.h to png.h because they must be visible to applications
-    that call png_set_unknown_chunks().
-  Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
-    before IDAT.
-
-Version 1.5.3beta08 [May 16, 2011]
-  Improved "pngvalid --speed" to exclude more of pngvalid from the time.
-  Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
-  The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
-    parameters are supplied by the caller), while in the absence of cHRM
-    sRGB/Rec 709 values are still used.  This introduced a divide-by-zero
-    bug in png_handle_cHRM().
-  The bKGD chunk no longer overwrites the background value set by
-    png_set_background(), allowing the latter to be used before the file
-    header is read. It never performed any useful function to override
-    the default anyway.
-  Added memory overwrite and palette image checks to pngvalid.c
-    Previously palette image code was poorly checked. Since the transformation
-    code has a special palette path in most cases this was a severe weakness.
-  Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
-    expanding an indexed image, always expand to RGBA if transparency is
-    present.
-
-Version 1.5.3beta09 [May 17, 2011]
-  Reversed earlier 1.5.3 change of transformation order; move png_expand_16
-    back where it was.  The change doesn't work because it requires 16-bit
-    gamma tables when the code only generates 8-bit ones.  This fails
-    silently; the libpng code just doesn't do any gamma correction.  Moving
-    the tests back leaves the old, inaccurate, 8-bit gamma calculations, but
-    these are clearly better than none!
-
-Version 1.5.3beta10 [May 20, 2011]
-
-  png_set_background() and png_expand_16() did not work together correctly.
-    This problem is present in 1.5.2; if png_set_background is called with
-    need_expand false and the matching 16 bit color libpng erroneously just
-    treats it as an 8-bit color because of where png_do_expand_16 is in the
-    transform list.  This simple fix reduces the supplied colour to 8-bits,
-    so it gets smashed, but this is better than the current behavior.
-  Added tests for expand16, more fixes for palette image tests to pngvalid.
-    Corrects the code for palette image tests and disables attempts to
-    validate palette colors.
-
-Version 1.5.3rc01 [June 3, 2011]
-  No changes.
-
-Version 1.5.3rc02 [June 8, 2011]
-  Fixed uninitialized memory read in png_format_buffer() (Bug report by
-    Frank Busse, CVE-2011-2501, related to CVE-2004-0421).
-
-Version 1.5.3beta11 [June 11, 2011]
-  Fixed png_handle_sCAL which is broken in 1.5. This fixes CVE 2011-2692.
-  Added sCAL to pngtest.png
-  Revised documentation about png_set_user_limits() to say that it also affects
-    png writing.
-  Revised handling of png_set_user_limits() so that it can increase the
-    limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only
-    reduce it.
-  Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is
-    wrong (high by one) 25% of the time. Dividing by 257 with rounding is
-    wrong in 128 out of 65536 cases. Getting the right answer all the time
-    without division is easy.
-  Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro.
-  Added projects/owatcom, an IDE project for OpenWatcom to replace
-    scripts/makefile.watcom.  This project works with OpenWatcom 1.9. The
-    IDE autogenerates appropriate makefiles (libpng.mk) for batch processing.
-    The project is configurable, unlike the Visual Studio project, so long
-    as the developer has an awk.
-  Changed png_set_gAMA to limit the gamma value range so that the inverse
-    of the stored value cannot overflow the fixed point representation,
-    and changed other things OpenWatcom warns about.
-  Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows
-    pngvalid to build when ALPHA_MODE is not supported, which is required if
-    it is to build on libpng 1.4.
-  Removed string/memory macros that are no longer used and are not
-    necessarily fully supportable, particularly png_strncpy and png_snprintf.
-  Added log option to pngvalid.c and attempted to improve gamma messages.
-
-Version 1.5.3 [omitted]
-  People found the presence of a beta release following an rc release
-    to be confusing; therefore we bump the version to libpng-1.5.4beta01
-    and there will be no libpng-1.5.3 release.
-
-Version 1.5.4beta01 [June 14, 2011]
-  Made it possible to undefine PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
-    to get the same (inaccurate) output as libpng-1.5.2 and earlier.
-  Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE
-    outside of an unknown-chunk block in png.h because they are also
-    needed for other uses.
-
-Version 1.5.4beta02 [June 14, 2011]
-  Fixed and clarified LEGACY 16-to-8 scaling code.
-  Added png_set_chop_16() API, to match inaccurate results from previous
-    libpng versions.
-  Removed the ACCURATE and LEGACY options (they are no longer useable)
-  Use the old scaling method for background if png_set_chop_16() was
-    called.
-  Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED
-
-Version 1.5.4beta03 [June 15, 2011]
-  Fixed a problem in png_do_expand_palette() exposed by optimization in
-    1.5.3beta06
-  Also removed a spurious and confusing "trans" member ("trans") from png_info.
-  The palette expand optimization prevented expansion to an intermediate RGBA
-    form if tRNS was present but alpha was marked to be stripped; this exposed
-    a check for tRNS in png_do_expand_palette() which is inconsistent with the
-    code elsewhere in libpng.
-  Correction to the expand_16 code; removed extra instance of
-    png_set_scale_16_to_8 from pngpriv.h
-
-Version 1.5.4beta04 [June 16, 2011]
-  Added a missing "#ifdef PNG_READ_BACKGROUND_SUPPORTED/#endif" in pngrtran.c
-  Added PNG_TRANSFORM_CHOP_16 to the high-level read transforms.
-  Made PNG_READ_16_TO_8_ACCURATE_SCALE configurable again.  If this is
-    not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built.
-  Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8
-
-Version 1.5.4beta05 [June 16, 2011]
-  Renamed png_set_strip_16() to png_set_scale_16() and renamed
-    png_set_chop_16() to png_set_strip(16) in an attempt to minimize the
-    behavior changes between libpng14 and libpng15.
-
-Version 1.5.4beta06 [June 18, 2011]
-  Fixed new bug that was causing both strip_16 and scale_16 to be applied.
-
-Version 1.5.4beta07 [June 19, 2011]
-  Fixed pngvalid, simplified macros, added checking for 0 in sCAL.
-    The ACCURATE scale macro is no longer defined in 1.5 - call the
-    png_scale_16_to_8 API.  Made sure that PNG_READ_16_TO_8 is still defined
-    if the png_strip_16_to_8 API is present.  png_check_fp_number now
-    maintains some state so that positive, negative and zero values are
-    identified.  sCAL uses these to be strictly spec conformant.
-
-Version 1.5.4beta08 [June 23, 2011]
-  Fixed pngvalid if ACCURATE_SCALE is defined.
-  Updated scripts/pnglibconf.h.prebuilt.
-
-Version 1.5.4rc01 [June 30, 2011]
-  Define PNG_ALLOCATED to "restrict" only if MSC_VER >= 1400.
-
-Version 1.5.4 [July 7, 2011]
-  No changes.
-
-Version 1.5.5beta01 [July 13, 2011]
-  Fixed some typos and made other minor changes in the manual.
-  Updated contrib/pngminus/makefile.std (Samuli Souminen)
-
-Version 1.5.5beta02 [July 14, 2011]
-  Revised Makefile.am and Makefile.in to look in the right directory for
-    pnglibconf.h.prebuilt
-
-Version 1.5.5beta03 [July 27, 2011]
-  Enabled compilation with g++ compiler.  This compiler does not recognize
-    the file extension, so it always compiles with C++ rules.  Made minor
-    changes to pngrutil.c to cast results where C++ expects it but C does not.
-  Minor editing of libpng.3 and libpng-manual.txt.
-
-Version 1.5.5beta04 [July 29, 2011]
-  Revised CMakeLists.txt (Clifford Yapp)
-  Updated commentary about the png_rgb_to_gray() default coefficients
-    in the manual and in pngrtran.c
-
-Version 1.5.5beta05 [August 17, 2011]
-  Prevent unexpected API exports from non-libpng DLLs on Windows.  The "_DLL"
-    is removed from the test of whether a DLL is being built (this erroneously
-    caused the libpng APIs to be marked as DLL exports in static builds under
-    Microsoft Visual Studio).  Almost all of the libpng building configuration
-    is moved from pngconf.h to pngpriv.h, but PNG_DLL_EXPORT remains in
-    pngconf.h, though, so that it is colocated with the import definition (it
-    is no longer used anywhere in the installed headers).  The VStudio project
-    definitions have been cleaned up: "_USRDLL" has been removed from the
-    static library builds (this was incorrect), and PNG_USE_DLL has been added
-    to pngvalid to test the functionality (pngtest does not supply it,
-    deliberately).  The spurious "_EXPORTS" has been removed from the
-    libpng build (all these errors were a result of copy/paste between project
-    configurations.)
-  Added new types and internal functions for CIE RGB end point handling to
-    pngpriv.h (functions yet to be implemented).
-
-Version 1.5.5beta06 [August 26, 2011]
-  Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set in CMakeLists.txt
-    (Clifford Yap)
-  Fixes to rgb_to_gray and cHRM XYZ APIs (John Bowler):
-    The rgb_to_gray code had errors when combined with gamma correction.
-    Some pixels were treated as true grey when they weren't and such pixels
-    and true grey ones were not gamma corrected (the original value of the
-    red component was used instead).  APIs to get and set cHRM using color
-    space end points have been added and the rgb_to_gray code that defaults
-    based on cHRM, and the divide-by-zero bug in png_handle_cHRM (CERT
-    VU#477046, CVE-2011-3328, introduced in 1.5.4) have been corrected.
-  A considerable number of tests has been added to pngvalid for the
-    rgb_to_gray transform.
-  Arithmetic errors in rgb_to_gray whereby the calculated gray value was
-    truncated to the bit depth rather than rounded have been fixed except in
-    the 8-bit non-gamma-corrected case (where consistency seems more important
-    than correctness.)  The code still has considerable inaccuracies in the
-    8-bit case because 8-bit linear arithmetic is used.
-
-Version 1.5.5beta07 [September 7, 2011]
-  Added "$(ARCH)" option to makefile.darwin
-  Added SunOS support to configure.ac and Makefile.am
-  Changed png_chunk_benign_error() to png_warning() in png.c, in
-    png_XYZ_from_xy_checked().
-
-Version 1.5.5beta08 [September 10, 2011]
-  Fixed 64-bit compilation errors (gcc). The errors fixed relate
-    to conditions where types that are 32 bits in the GCC 32-bit
-    world (uLong and png_size_t) become 64 bits in the 64-bit
-    world.  This produces potential truncation errors which the
-    compiler correctly flags.
-  Relocated new HAVE_SOLARIS_LD definition in configure.ac
-  Constant changes for 64-bit compatibility (removal of L suffixes). The
-    16-bit cases still use "L" as we don't have a 16-bit test system.
-
-Version 1.5.5rc01 [September 15, 2011]
-  Removed "L" suffixes in pngpriv.h
-
-Version 1.5.5 [September 22, 2011]
-  No changes.
-
-Version 1.5.6beta01 [September 22, 2011]
-  Fixed some 64-bit type conversion warnings in pngrtran.c
-  Moved row_info from png_struct to a local variable.
-  The various interlace mask arrays have been made into arrays of
-    bytes and made PNG_CONST and static (previously some arrays were
-    marked PNG_CONST and some weren't).
-  Additional checks have been added to the transform code to validate the
-    pixel depths after the transforms on both read and write.
-  Removed some redundant code from pngwrite.c, in png_destroy_write_struct().
-  Changed chunk reading/writing code to use png_uint_32 instead of png_byte[4].
-    This removes the need to allocate temporary strings for chunk names on
-    the stack in the read/write code.  Unknown chunk handling still uses the
-    string form because this is exposed in the API.
-
-Version 1.5.6beta02 [September 26, 2011]
-  Added a note in the manual the png_read_update_info() must be called only
-    once with a particular info_ptr.
-  Fixed a typo in the definition of the new PNG_STRING_FROM_CHUNK(s,c) macro.
-
-Version 1.5.6beta03 [September 28, 2011]
-  Revised test-pngtest.sh to report FAIL when pngtest fails.
-  Added "--strict" option to pngtest, to report FAIL when the failure is
-    only because the resulting valid files are different.
-  Revised CMakeLists.txt to work with mingw and removed some material from
-    CMakeLists.txt that is no longer useful in libpng-1.5.
-
-Version 1.5.6beta04 [October 5, 2011]
-  Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")."
-
-Version 1.5.6beta05 [October 12, 2011]
-  Speed up png_combine_row() for interlaced images. This reduces the generality
-    of the code, allowing it to be optimized for Adam7 interlace.  The masks
-    passed to png_combine_row() are now generated internally, avoiding
-    some code duplication and localizing the interlace handling somewhat.
-  Align png_struct::row_buf - previously it was always unaligned, caused by
-    a bug in the code that attempted to align it; the code needs to subtract
-    one from the pointer to take account of the filter byte prepended to
-    each row.
-  Optimized png_combine_row() when rows are aligned. This gains a small
-    percentage for 16-bit and 32-bit pixels in the typical case where the
-    output row buffers are appropriately aligned. The optimization was not
-    previously possible because the png_struct buffer was always misaligned.
-  Fixed bug in png_write_chunk_header() debug print, introduced in 1.5.6beta01.
-
-Version 1.5.6beta06 [October 17, 2011]
-  Removed two redundant tests for unitialized row.
-  Fixed a relatively harmless memory overwrite in compressed text writing
-    with a 1 byte zlib buffer.
-  Add ability to call png_read_update_info multiple times to pngvalid.c.
-  Fixes for multiple calls to png_read_update_info. These fixes attend to
-    most of the errors revealed in pngvalid, however doing the gamma work
-    twice results in inaccuracies that can't be easily fixed.  There is now
-    a warning in the code if this is going to happen.
-  Turned on multiple png_read_update_info in pngvalid transform tests.
-  Prevent libpng from overwriting unused bits at the end of the image when
-    it is not byte aligned, while reading. Prior to libpng-1.5.6 libpng would
-    overwrite the partial byte at the end of each row if the row width was not
-    an exact multiple of 8 bits and the image is not interlaced.
-
-Version 1.5.6beta07 [October 21, 2011]
-  Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row
-    (Mans Rullgard).
-
-Version 1.5.6rc01 [October 26, 2011]
-  Changed misleading "Missing PLTE before cHRM" warning to "Out of place cHRM"
-
-Version 1.5.6rc02 [October 27, 2011]
-  Added LSR() macro to defend against buggy compilers that evaluate non-taken
-    code branches and complain about out-of-range shifts.
-
-Version 1.5.6rc03 [October 28, 2011]
-  Renamed the LSR() macro to PNG_LSR() and added PNG_LSL() macro.
-  Fixed compiler warnings with Intel and MSYS compilers. The logical shift
-    fix for Microsoft Visual C is required by other compilers, so this
-    enables that fix for all compilers when using compile-time constants.
-    Under MSYS 'byte' is a name declared in a system header file, so we
-    changed the name of a local variable to avoid the warnings that result.
-  Added #define PNG_ALIGN_TYPE PNG_ALIGN_NONE to contrib/pngminim/*/pngusr.h
-
-Version 1.5.6 [November 3, 2011]
-  No changes.
-
-Version 1.5.7beta01 [November 4, 2011]
-  Added support for ARM processor (Mans Rullgard)
-  Fixed bug in pngvalid on early allocation failure; fixed type cast in
-    pngmem.c; pngvalid would attempt to call png_error() if the allocation
-    of a png_struct or png_info failed. This would probably have led to a
-    crash.  The pngmem.c implementation of png_malloc() included a cast
-    to png_size_t which would fail on large allocations on 16-bit systems.
-  Fix for the preprocessor of the Intel C compiler. The preprocessor
-    splits adjacent @ signs with a space; this changes the concatentation
-    token from @-@-@ to PNG_JOIN; that should work with all compiler
-    preprocessors.
-  Paeth filter speed improvements from work by Siarhei Siamashka. This
-    changes the 'Paeth' reconstruction function to improve the GCC code
-    generation on x86. The changes are only part of the suggested ones;
-    just the changes that definitely improve speed and remain simple.
-    The changes also slightly increase the clarity of the code.
-
-Version 1.5.7beta02 [November 11, 2011]
-  Check compression_type parameter in png_get_iCCP and remove spurious
-    casts. The compression_type parameter is always assigned to, so must
-    be non-NULL. The cast of the profile length potentially truncated the
-    value unnecessarily on a 16-bit int system, so the cast of the (byte)
-    compression type to (int) is specified by ANSI-C anyway.
-  Fixed FP division by zero in pngvalid.c; the 'test_pixel' code left
-    the sBIT fields in the test pixel as 0, which resulted in a floating
-    point division by zero which was irrelevant but causes systems where
-    FP exceptions cause a crash. Added code to pngvalid to turn on FP
-    exceptions if the appropriate glibc support is there to ensure this is
-    tested in the future.
-  Updated scripts/pnglibconf.mak and scripts/makefile.std to handle the
-    new PNG_JOIN macro.
-  Added versioning to pnglibconf.h comments.
-  Simplified read/write API initial version; basic read/write tested on
-    a variety of images, limited documentation (in the header file.)
-  Installed more accurate linear to sRGB conversion tables. The slightly
-    modified tables reduce the number of 16-bit values that
-    convert to an off-by-one 8-bit value.  The "makesRGB.c" code that was used
-    to generate the tables is now in a contrib/sRGBtables sub-directory.
-
-Version 1.5.7beta03 [November 17, 2011]
-  Removed PNG_CONST from the sRGB table declarations in pngpriv.h and png.c
-  Added run-time detection of NEON support.
-  Added contrib/libtests; includes simplified API test and timing test and
-    a color conversion utility for rapid checking of failed 'pngstest' results.
-  Multiple transform bug fixes plus a work-round for double gamma correction.
-    libpng does not support more than one transform that requires linear data
-    at once - if this is tried typically the results is double gamma
-    correction. Since the simplified APIs can need rgb to gray combined with
-    a compose operation it is necessary to do one of these outside the main
-    libpng transform code. This check-in also contains fixes to various bugs
-    in the simplified APIs themselves and to some bugs in compose and rgb to
-    gray (on palette) itself.
-  Fixes for C++ compilation using g++ When libpng source is compiled
-    using g++. The compiler imposes C++ rules on the C source; thus it
-    is desireable to make the source work with either C or C++ rules
-    without throwing away useful error information.  This change adds
-    png_voidcast to allow C semantic (void*) cases or the corresponding
-    C++ static_cast operation, as appropriate.
-  Added --noexecstack to assembler file compilation. GCC does not set
-    this on assembler compilation, even though it does on C compilation.
-    This creates security issues if assembler code is enabled; the
-    work-around is to set it by default in the flags for $(CCAS)
-  Work around compilers that don't support declaration of const data. Some
-    compilers fault 'extern const' data declarations (because the data is
-    not initialized); this turns on const-ness only for compilers where
-    this is known to work.
-
-Version 1.5.7beta04 [November 17, 2011]
-  Since the gcc driver does not recognize the --noexecstack flag, we must
-    use the -Wa prefix to have it passed through to the assembler.
-    Also removed a duplicate setting of this flag.
-  Added files that were omitted from the libpng-1.5.7beta03 zip distribution.
-
-Version 1.5.7beta05 [November 25, 2011]
-  Removed "zTXt" from warning in generic chunk decompression function.
-  Validate time settings passed to pngset() and png_convert_to_rfc1123()
-    (Frank Busse).
-  Added MINGW support to CMakeLists.txt
-  Reject invalid compression flag or method when reading the iTXt chunk.
-  Backed out 'simplified' API changes. The API seems too complex and there
-    is a lack of consensus or enthusiasm for the proposals.  The API also
-    reveals significant bugs inside libpng (double gamma correction and the
-    known bug of being unable to retrieve a corrected palette). It seems
-    better to wait until the bugs, at least, are corrected.
-  Moved pngvalid.c into contrib/libtests
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.68
-
-Version 1.5.7rc01 [December 1, 2011]
-  Replaced an "#if" with "#ifdef" in pngrtran.c
-  Revised #if PNG_DO_BC block in png.c (use #ifdef and add #else)
-
-Version 1.5.7rc02 [December 5, 2011]
-  Revised project files and contrib/pngvalid/pngvalid.c to account for
-    the relocation of pngvalid into contrib/libtests.
-  Revised pngconf.h to use " __declspec(restrict)" only when MSC_VER >= 1400,
-    as in libpng-1.5.4.
-  Put CRLF line endings in the owatcom project files.
-
-Version 1.5.7rc03 [December 7, 2011]
-  Updated CMakeLists.txt to account for the relocation of pngvalid.c
-
-Version 1.5.7 [December 15, 2011]
-  Minor fixes to pngvalid.c for gcc 4.6.2 compatibility to remove warnings
-    reported by earlier versions.
-
-Version 1.5.8beta01 [January 15, 2011]
-  Removed '#include config.h"' from contrib/libtests/pngvalid.c.  It's not
-    needed and causes trouble for VPATH building.
-  Moved AC_MSG_CHECKING([if libraries can be versioned]) later to the proper
-    location in configure.ac (Gilles Espinasse).
-  Fix bug in pngerror.c: some long warnings were being improperly truncated
-    (CVE-2011-3464, bug introduced in libpng-1.5.3beta05).
-
-Version 1.5.8rc01 [January 21, 2012]
-  No changes.
-
-Version 1.5.8rc02 [January 25, 2012]
-  Fixed Min/GW uninstall to remove libpng.dll.a
-  Conditionalize the install rules for MINGW and CYGWIN in CMakeLists.txt
-
-Version 1.5.8 [February 1, 2012]
-  No changes.
-
-Version 1.5.9beta01 [February 3, 2012]
-  Rebuilt configure scripts in the tar distributions.
-
-Version 1.5.9beta02 [February 16, 2012]
-  Removed two unused definitions from scripts/pnglibconf.h.prebuilt
-  Removed some unused arrays (with #ifdef) from png_read_push_finish_row().
-  Removed tests for no-longer-used *_EMPTY_PLTE_SUPPORTED from pngstruct.h
-
-Version 1.5.9rc01 [February 17, 2012]
-  Fixed CVE-2011-3026 buffer overrun bug.  This bug was introduced when
-    iCCP chunk support was added at libpng-1.0.6. Deal more correctly with the
-    test on iCCP chunk length. Also removed spurious casts that may hide
-    problems on 16-bit systems.
-
-Version 1.5.9 [February 18, 2012]
-  No changes.
-
-Version 1.5.10beta01 [February 24, 2012]
-  Removed two useless #ifdef directives from pngread.c and one from pngrutil.c
-  Always put the CMAKE_LIBRARY in "lib" (removed special WIN32 case).
-  Removed empty vstudio/pngstest directory (Clifford Yapp).
-  Eliminated redundant png_push_read_tEXt|zTXt|iTXt|unknown code from
-    pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
-    now that png_ptr->buffer is inaccessible to applications, the special
-    handling is no longer useful.
-  Fixed bug with png_handle_hIST with odd chunk length (Frank Busse).
-  Added PNG_SAFE_LIMITS feature to pnglibconf.dfa and code in pngconf.h
-    to reset the user limits to safe ones if PNG_SAFE_LIMITS is defined.
-    To enable, use "CPPFLAGS=-DPNG_SAFE_LIMITS_SUPPORTED" on the configure
-    command or put "#define PNG_SAFE_LIMITS_SUPPORTED" in pnglibconf.h.
-  Revised the SAFE_LIMITS feature to be the same as the feature in libpng16.
-  Added information about the new limits in the manual.
-
-Version 1.5.10beta02 [February 27, 2012]
-  Updated Makefile.in
-
-Version 1.5.10beta03 [March 6, 2012]
-  Removed unused "current_text" members of png_struct and the png_free()
-    of png_ptr->current_text from pngread.c
-  Added palette-index checking. Issue a png_warning() if an invalid index is
-    found.
-
-Version 1.5.10beta04 [March 10, 2012]
-  Fixed PNG_LIBPNG_BUILD_BASE_TYPE definition.
-  Fixed CMF optimization of non-IDAT compressed chunks, which was added at
-    libpng-1.5.4.  It sometimes produced too small of a window.
-
-Version 1.5.10beta05 [March 10, 2012]
-  Reject all iCCP chunks after the first, even if the first one is invalid.
-  Issue a png_benign_error() instead of png_warning() about bad palette index.
-  Fixed an off-by-one error in the palette index checking function.
-  Revised example.c to put text strings in a temporary character array
-    instead of directly assigning string constants to png_textp members.
-    This avoids compiler warnings when -Wwrite-strings is enabled.
-
-Version 1.5.10 [March 29, 2012]
-  Prevent PNG_EXPAND+PNG_SHIFT doing the shift twice.
-  Revised png_set_text_2() to avoid potential memory corruption (fixes
-    CVE-2011-3048).
-
-Send comments/corrections/commendations to png-mng-implement at lists.sf.net
-(subscription required; visit
-https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe)
-or to glennrp at users.sourceforge.net
-
-Glenn R-P
-#endif
diff --git a/extern/libpng/include/CMakeLists.txt b/extern/libpng/include/CMakeLists.txt
deleted file mode 100644
index 15f7e3a8fc..0000000000
--- a/extern/libpng/include/CMakeLists.txt
+++ /dev/null
@@ -1,340 +0,0 @@
-# CMakeLists.txt
-
-# Copyright (C) 2007-2011 Glenn Randers-Pehrson
-
-# This code is released under the libpng license. For conditions of distribution
-# and use, see the disclaimer and license in png.h
-
-cmake_minimum_required(VERSION 2.4.4)
-set(CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS true)
-
-if(UNIX AND NOT DEFINED CMAKE_BUILD_TYPE)
-  if(CMAKE_MAJOR_VERSION EQUAL 2 AND CMAKE_MINOR_VERSION EQUAL 4)
-    # workaround CMake 2.4.x bug
-    set(CMAKE_BUILD_TYPE "RelWithDebInfo"
-        CACHE STRING "Choose the type of build, options are:
-           None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used)
-           Debug
-           Release
-           RelWithDebInfo
-           MinSizeRel.")
-  else()
-    set(CMAKE_BUILD_TYPE "RelWithDebInfo"
-        CACHE STRING "Choose the type of build, options are:
-           None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used)
-           Debug
-           Release
-           RelWithDebInfo
-           MinSizeRel.")
-  endif()
-endif()
-
-project(libpng C)
-enable_testing()
-
-set(PNGLIB_MAJOR 1)
-set(PNGLIB_MINOR 5)
-set(PNGLIB_RELEASE 10)
-set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
-set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})
-
-# needed packages
-find_package(ZLIB REQUIRED)
-include_directories(${ZLIB_INCLUDE_DIR})
-
-if(NOT WIN32)
-  find_library(M_LIBRARY NAMES m PATHS /usr/lib /usr/local/lib)
-  if(NOT M_LIBRARY)
-    message(
-      STATUS "math library 'libm' not found - floating point support disabled")
-  endif()
-else()
-  # not needed on windows
-  set(M_LIBRARY "")
-endif()
-
-# COMMAND LINE OPTIONS
-if(DEFINED PNG_SHARED)
-  option(PNG_SHARED "Build shared lib" ${PNG_SHARED})
-else()
-  option(PNG_SHARED "Build shared lib" ON)
-endif()
-if(DEFINED PNG_STATIC)
-  option(PNG_STATIC "Build static lib" ${PNG_STATIC})
-else()
-  option(PNG_STATIC "Build static lib" ON)
-endif()
-
-option(PNG_TESTS "Build libpng tests" YES)
-
-# Many more configuration options could be added here
-option(PNG_DEBUG "Build with debug output" NO)
-option(PNGARG "Disable ANSI-C prototypes" NO)
-
-# SET LIBNAME
-set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR})
-
-# to distinguish between debug and release lib
-set(CMAKE_DEBUG_POSTFIX "d")
-
-# Use the prebuilt pnglibconf.h file from the scripts folder TODO: fix this by
-# building with awk; without this no cmake build can be configured directly (to
-# do so indirectly use your local awk to build a pnglibconf.h in the build
-# directory.)
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt
-               ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h)
-include_directories(${CMAKE_CURRENT_BINARY_DIR})
-
-# OUR SOURCES
-set(libpng_public_hdrs png.h pngconf.h ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h)
-set(libpng_sources
-    ${libpng_public_hdrs}
-    pngdebug.h
-    pnginfo.h
-    pngpriv.h
-    pngstruct.h
-    png.c
-    pngerror.c
-    pngget.c
-    pngmem.c
-    pngpread.c
-    pngread.c
-    pngrio.c
-    pngrtran.c
-    pngrutil.c
-    pngset.c
-    pngtrans.c
-    pngwio.c
-    pngwrite.c
-    pngwtran.c
-    pngwutil.c)
-set(pngtest_sources pngtest.c)
-set(pngvalid_sources contrib/libtests/pngvalid.c)
-# SOME NEEDED DEFINITIONS
-
-add_definitions(-DPNG_CONFIGURE_LIBPNG)
-
-if(MSVC)
-  add_definitions(-D_CRT_SECURE_NO_DEPRECATE)
-endif(MSVC)
-
-if(PNG_DEBUG)
-  add_definitions(-DPNG_DEBUG)
-endif()
-
-# NOW BUILD OUR TARGET
-include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${ZLIB_INCLUDE_DIR})
-
-if(PNG_SHARED)
-  add_library(${PNG_LIB_NAME} SHARED ${libpng_sources})
-  if(MSVC)
-    # msvc does not append 'lib' - do it here to have consistent name
-    set_target_properties(${PNG_LIB_NAME} PROPERTIES PREFIX "lib")
-    set_target_properties(${PNG_LIB_NAME} PROPERTIES IMPORT_PREFIX "lib")
-  endif()
-  target_link_libraries(${PNG_LIB_NAME} ${ZLIB_LIBRARY} ${M_LIBRARY})
-endif()
-
-if(PNG_STATIC)
-  # does not work without changing name
-  set(PNG_LIB_NAME_STATIC ${PNG_LIB_NAME}_static)
-  add_library(${PNG_LIB_NAME_STATIC} STATIC ${libpng_sources})
-  if(MSVC)
-    # msvc does not append 'lib' - do it here to have consistent name
-    set_target_properties(${PNG_LIB_NAME_STATIC} PROPERTIES PREFIX "lib")
-  endif()
-  target_link_libraries(${PNG_LIB_NAME_STATIC} ${ZLIB_LIBRARY} ${M_LIBRARY})
-endif()
-
-if(PNG_SHARED AND WIN32)
-  set_target_properties(${PNG_LIB_NAME} PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
-endif()
-
-if(PNG_TESTS AND PNG_SHARED)
-  # does not work with msvc due to png_lib_ver issue
-  add_executable(pngtest ${pngtest_sources})
-  target_link_libraries(pngtest ${PNG_LIB_NAME})
-  add_test(pngtest ./pngtest ${CMAKE_CURRENT_SOURCE_DIR}/pngtest.png)
-  #
-  add_executable(pngvalid ${pngvalid_sources})
-  target_link_libraries(pngvalid ${PNG_LIB_NAME})
-  add_test(pngvalid ./pngvalid)
-endif()
-
-# Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set
-if(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
-  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "lib")
-endif(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
-
-# Set a variable with CMake code which: Creates a symlink from src to dest (if
-# possible) or alternatively copies if different.
-macro(CREATE_SYMLINK SRC_FILE DEST_FILE)
-  file(REMOVE ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
-  if(WIN32 AND NOT CYGWIN AND NOT MINGW)
-    add_custom_command(OUTPUT ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}
-                              ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
-                       COMMAND ${CMAKE_COMMAND} -E copy
-                               ${CMAKE_CURRENT_BINARY_DIR}/${SRC_FILE}
-                               ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}
-                       COMMAND ${CMAKE_COMMAND} -E copy
-                               ${CMAKE_CURRENT_BINARY_DIR}/${SRC_FILE}
-                               ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
-                       DEPENDS ${PNG_LIB_NAME} ${PNG_LIB_NAME_STATIC})
-    add_custom_target(${DEST_FILE}_COPY ALL
-                      DEPENDS ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
-  else(WIN32 AND NOT CYGWIN AND NOT MINGW)
-    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink ${SRC_FILE}
-                            ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}
-                    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
-    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink ${SRC_FILE}
-                            ${DEST_FILE}
-                    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
-  endif(WIN32 AND NOT CYGWIN AND NOT MINGW)
-endmacro()
-
-# libpng is a library so default to 'lib'
-if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
-  set(CMAKE_INSTALL_LIBDIR lib)
-endif(NOT DEFINED CMAKE_INSTALL_LIBDIR)
-
-# CREATE PKGCONFIG FILES we use the same files like ./configure, so we have to
-# set its vars Only do this on Windows for Cygwin - the files don't make much
-# sense outside a UNIX look alike
-if(NOT WIN32 OR CYGWIN OR MINGW)
-  set(prefix ${CMAKE_INSTALL_PREFIX})
-  set(exec_prefix ${CMAKE_INSTALL_PREFIX})
-  set(libdir ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR})
-  set(includedir ${CMAKE_INSTALL_PREFIX}/include)
-  set(LIBS "-lz -lm")
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in
-                 ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc @ONLY)
-  create_symlink(${PNGLIB_NAME}.pc libpng.pc)
-
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in
-                 ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config @ONLY)
-  create_symlink(${PNGLIB_NAME}-config libpng-config)
-endif(NOT WIN32 OR CYGWIN OR MINGW)
-
-# SET UP LINKS
-if(PNG_SHARED)
-  set_target_properties(${PNG_LIB_NAME}
-                        PROPERTIES # VERSION 15.${PNGLIB_RELEASE}.1.5.10
-                                   VERSION
-                                   15.${PNGLIB_RELEASE}.0
-                                   SOVERSION
-                                   15
-                                   CLEAN_DIRECT_OUTPUT
-                                   1)
-endif()
-if(PNG_STATIC)
-  # MSVC doesn't use a different file extension for shared vs. static libs.  We
-  # are able to change OUTPUT_NAME to remove the _static for all other
-  # platforms.
-  if(NOT MSVC)
-    set_target_properties(${PNG_LIB_NAME_STATIC}
-                          PROPERTIES OUTPUT_NAME
-                                     ${PNG_LIB_NAME}
-                                     CLEAN_DIRECT_OUTPUT
-                                     1)
-  endif()
-endif()
-
-# If CMake > 2.4.x, we set a variable used below to export targets to an export
-# file. TODO: Use VERSION_GREATER after our cmake_minimum_required >= 2.6.2
-if(CMAKE_MAJOR_VERSION GREATER 1 AND CMAKE_MINOR_VERSION GREATER 4)
-  set(PNG_EXPORT_RULE EXPORT libpng)
-elseif(CMAKE_MAJOR_VERSION GREATER 2) # future proof
-  set(PNG_EXPORT_RULE EXPORT libpng)
-endif()
-
-# INSTALL
-if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL)
-  if(PNG_SHARED)
-    install(TARGETS ${PNG_LIB_NAME} ${PNG_EXPORT_RULE}
-            RUNTIME DESTINATION bin
-            LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-            ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
-
-    # Create a symlink for libpng.dll.a => libpng15.dll.a on Cygwin
-    if(CYGWIN OR MINGW)
-      get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME}
-                          LOCATION_${CMAKE_BUILD_TYPE})
-      get_filename_component(BUILD_TARGET_FILE ${BUILD_TARGET_LOCATION} NAME)
-      create_symlink(${BUILD_TARGET_FILE} libpng${CMAKE_IMPORT_LIBRARY_SUFFIX})
-      install(
-        FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_IMPORT_LIBRARY_SUFFIX}
-        DESTINATION ${CMAKE_INSTALL_LIBDIR})
-    endif(CYGWIN OR MINGW)
-
-    if(NOT WIN32)
-      get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME}
-                          LOCATION_${CMAKE_BUILD_TYPE})
-      get_filename_component(BUILD_TARGET_FILE ${BUILD_TARGET_LOCATION} NAME)
-      create_symlink(${BUILD_TARGET_FILE} libpng${CMAKE_SHARED_LIBRARY_SUFFIX})
-      install(
-        FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
-        DESTINATION ${CMAKE_INSTALL_LIBDIR})
-    endif(NOT WIN32)
-  endif(PNG_SHARED)
-
-  if(PNG_STATIC)
-    install(TARGETS ${PNG_LIB_NAME_STATIC} ${PNG_EXPORT_RULE}
-            LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-            ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
-    if(NOT WIN32 OR CYGWIN OR MINGW)
-      get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME_STATIC}
-                          LOCATION_${CMAKE_BUILD_TYPE})
-      get_filename_component(BUILD_TARGET_FILE ${BUILD_TARGET_LOCATION} NAME)
-      create_symlink(${BUILD_TARGET_FILE} libpng${CMAKE_STATIC_LIBRARY_SUFFIX})
-      install(
-        FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
-        DESTINATION ${CMAKE_INSTALL_LIBDIR})
-    endif(NOT WIN32 OR CYGWIN OR MINGW)
-  endif()
-endif()
-
-if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL)
-  install(FILES ${libpng_public_hdrs} DESTINATION include)
-  install(FILES ${libpng_public_hdrs} DESTINATION include/${PNGLIB_NAME})
-endif()
-if(NOT SKIP_INSTALL_EXECUTABLES AND NOT SKIP_INSTALL_ALL)
-  if(NOT WIN32 OR CYGWIN OR MINGW)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config DESTINATION bin)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
-            DESTINATION bin)
-  endif(NOT WIN32 OR CYGWIN OR MINGW)
-endif()
-
-if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL)
-  # Install man pages
-  if(NOT PNG_MAN_DIR)
-    set(PNG_MAN_DIR "share/man")
-  endif()
-  install(FILES libpng.3 libpngpf.3 DESTINATION ${PNG_MAN_DIR}/man3)
-  install(FILES png.5 DESTINATION ${PNG_MAN_DIR}/man5)
-  # Install pkg-config files
-  if(NOT WIN32 OR CYGWIN OR MINGW)
-    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc
-            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config DESTINATION bin)
-    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc
-            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
-            DESTINATION bin)
-  endif(NOT WIN32 OR CYGWIN OR MINGW)
-endif()
-
-# On versions of CMake that support it, create an export file CMake users can
-# include() to import our targets
-if(PNG_EXPORT_RULE AND NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL)
-  install(EXPORT libpng DESTINATION lib/libpng FILE lib${PNG_LIB_NAME}.cmake)
-endif()
-
-# what's with libpng-$VER%.txt and all the extra files?
-
-# UNINSTALL do we need this?
-
-# DIST do we need this?
-
-# to create msvc import lib for mingw compiled shared lib pexports libpng.dll >
-# libpng.def lib /def:libpng.def /machine:x86
diff --git a/extern/libpng/include/INSTALL b/extern/libpng/include/INSTALL
deleted file mode 100644
index e6979c6fb0..0000000000
--- a/extern/libpng/include/INSTALL
+++ /dev/null
@@ -1,155 +0,0 @@
-
-Installing libpng
-
-On Unix/Linux and similar systems, you can simply type
-
-    ./configure [--prefix=/path]
-    make check
-    make install
-
-and ignore the rest of this document.
-
-If configure does not work on your system and you have a reasonably
-up-to-date set of tools, running ./autogen.sh before running ./configure
-may fix the problem.  You can also run the individual commands in
-autogen.sh with the --force option, if supported by your version of
-the tools.  To be really sure that you aren't using any of the included
-pre-built scripts, you can do this:
-
-    ./configure --enable-maintainer-mode
-    make maintainer-clean
-    ./autogen.sh
-    ./configure [--prefix=/path] [other options]
-    make
-    make install
-    make check
-
-Instead, you can use one of the custom-built makefiles in the
-"scripts" directory
-
-    cp scripts/makefile.system makefile
-    make test
-    make install
-
-The files that are presently available in the scripts directory
-are listed and described in scripts/README.txt.
-
-Or you can use one of the "projects" in the "projects" directory.
-
-Before installing libpng, you must first install zlib, if it
-is not already on your system.  zlib can usually be found
-wherever you got libpng.  zlib can be placed in another directory,
-at the same level as libpng.
-
-If you want to use "cmake" (see www.cmake.org), type
-
-   cmake . -DCMAKE_INSTALL_PREFIX=/path
-   make
-   make install
-
-If your system already has a preinstalled zlib you will still need
-to have access to the zlib.h and zconf.h include files that
-correspond to the version of zlib that's installed.
-
-You can rename the directories that you downloaded (they
-might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.5"
-or "zlib125") so that you have directories called "zlib" and "libpng".
-
-Your directory structure should look like this:
-
-   ..       (the parent directory)
-      libpng  (this directory)
-          INSTALL (this file)
-          README
-          *.h
-          *.c
-          CMakeLists.txt    =>  "cmake" script
-          configuration files:
-             configure.ac, configure, Makefile.am, Makefile.in,
-             autogen.sh, config.guess, ltmain.sh, missing, libpng.pc.in,
-             libpng-config.in, aclocal.m4, config.h.in, config.sub,
-             depcomp, install-sh, mkinstalldirs, test-pngtest.sh
-          contrib
-             gregbook
-             pngminim
-             pngminus
-             pngsuite
-             visupng
-          projects
-             visualc71
-             vstudio
-          scripts
-             makefile.*
-             *.def (module definition files)
-             etc.
-          pngtest.png
-          etc.
-      zlib
-          README
-          *.h
-          *.c
-          contrib
-          etc.
-
-If the line endings in the files look funny, you may wish to get the other
-distribution of libpng.  It is available in both tar.gz (UNIX style line
-endings) and zip (DOS style line endings) formats.
-
-If you are building libpng with MSVC, you can enter the
-libpng projects\visualc6 or visualc71 directory and follow the instructions
-in README.txt.
-
-Otherwise enter the zlib directory and follow the instructions in zlib/README,
-then come back here and run "configure" or choose the appropriate
-makefile.sys in the scripts directory.
-
-Copy the file (or files) that you need from the
-scripts directory into this directory, for example
-
-   MSDOS example: copy scripts\makefile.msc makefile
-   UNIX example:    cp scripts/makefile.std makefile
-
-Read the makefile to see if you need to change any source or
-target directories to match your preferences.
-
-Then read pnglibconf.dfa to see if you want to make any configuration
-changes.
-
-Then just run "make" which will create the libpng library in
-this directory and "make test" which will run a quick test that reads
-the "pngtest.png" file and writes a "pngout.png" file that should be
-identical to it.  Look for "9782 zero samples" in the output of the
-test.  For more confidence, you can run another test by typing
-"pngtest pngnow.png" and looking for "289 zero samples" in the output.
-Also, you can run "pngtest -m contrib/pngsuite/*.png" and compare
-your output with the result shown in contrib/pngsuite/README.
-
-Most of the makefiles will allow you to run "make install" to
-put the library in its final resting place (if you want to
-do that, run "make install" in the zlib directory first if necessary).
-Some also allow you to run "make test-installed" after you have
-run "make install".
-
-Further information can be found in the README and libpng-manual.txt
-files, in the individual makefiles, in png.h, and the manual pages
-libpng.3 and png.5.
-
-Using the ./configure script -- 16 December 2002.
-=================================================
-
-The ./configure script should work compatibly with what scripts/makefile.*
-did, however there are some options you might need to add to configure
-explicitly, which previously was done semi-automatically (if you didn't edit
-scripts/makefile.* yourself, that is)
-
-CFLAGS="-Wall -O -funroll-loops \
--malign-loops=2 -malign-functions=2" ./configure --prefix=/usr/include \
---with-pkgconfigdir=/usr/lib/pkgconfig --includedir=/usr/include
-
-You can alternatively specify --includedir=/usr/include, /usr/local/include,
-/usr/include/libpng%NN%, or whatever.
-
-If you find that the configure script is out-of-date or is not supporting
-your platform properly, try running autogen.sh to regenerate "configure",
-"Makefile.in", and the other configuration files. Then try configure again.
-
diff --git a/extern/libpng/include/LICENSE b/extern/libpng/include/LICENSE
deleted file mode 100644
index b72d1258e3..0000000000
--- a/extern/libpng/include/LICENSE
+++ /dev/null
@@ -1,111 +0,0 @@
-
-This copy of the libpng notices is provided for your convenience.  In case of
-any discrepancy between this copy and the notices in the file png.h that is
-included in the libpng distribution, the latter shall prevail.
-
-COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
-
-If you modify libpng you may insert additional notices immediately following
-this sentence.
-
-This code is released under the libpng license.
-
-libpng versions 1.2.6, August 15, 2004, through 1.5.10, March 29, 2012, are
-Copyright (c) 2004, 2006-2011 Glenn Randers-Pehrson, and are
-distributed according to the same disclaimer and license as libpng-1.2.5
-with the following individual added to the list of Contributing Authors
-
-   Cosmin Truta
-
-libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
-Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
-distributed according to the same disclaimer and license as libpng-1.0.6
-with the following individuals added to the list of Contributing Authors
-
-   Simon-Pierre Cadieux
-   Eric S. Raymond
-   Gilles Vollant
-
-and with the following additions to the disclaimer:
-
-   There is no warranty against interference with your enjoyment of the
-   library or against infringement.  There is no warranty that our
-   efforts or the library will fulfill any of your particular purposes
-   or needs.  This library is provided with all faults, and the entire
-   risk of satisfactory quality, performance, accuracy, and effort is with
-   the user.
-
-libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
-Copyright (c) 1998, 1999 Glenn Randers-Pehrson, and are
-distributed according to the same disclaimer and license as libpng-0.96,
-with the following individuals added to the list of Contributing Authors:
-
-   Tom Lane
-   Glenn Randers-Pehrson
-   Willem van Schaik
-
-libpng versions 0.89, June 1996, through 0.96, May 1997, are
-Copyright (c) 1996, 1997 Andreas Dilger
-Distributed according to the same disclaimer and license as libpng-0.88,
-with the following individuals added to the list of Contributing Authors:
-
-   John Bowler
-   Kevin Bracey
-   Sam Bushell
-   Magnus Holmgren
-   Greg Roelofs
-   Tom Tanner
-
-libpng versions 0.5, May 1995, through 0.88, January 1996, are
-Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-
-For the purposes of this copyright and license, "Contributing Authors"
-is defined as the following set of individuals:
-
-   Andreas Dilger
-   Dave Martindale
-   Guy Eric Schalnat
-   Paul Schmidt
-   Tim Wegner
-
-The PNG Reference Library is supplied "AS IS".  The Contributing Authors
-and Group 42, Inc. disclaim all warranties, expressed or implied,
-including, without limitation, the warranties of merchantability and of
-fitness for any purpose.  The Contributing Authors and Group 42, Inc.
-assume no liability for direct, indirect, incidental, special, exemplary,
-or consequential damages, which may result from the use of the PNG
-Reference Library, even if advised of the possibility of such damage.
-
-Permission is hereby granted to use, copy, modify, and distribute this
-source code, or portions hereof, for any purpose, without fee, subject
-to the following restrictions:
-
-1. The origin of this source code must not be misrepresented.
-
-2. Altered versions must be plainly marked as such and must not
-   be misrepresented as being the original source.
-
-3. This Copyright notice may not be removed or altered from any
-   source or altered source distribution.
-
-The Contributing Authors and Group 42, Inc. specifically permit, without
-fee, and encourage the use of this source code as a component to
-supporting the PNG file format in commercial products.  If you use this
-source code in a product, acknowledgment is not required but would be
-appreciated.
-
-
-A "png_get_copyright" function is available, for convenient use in "about"
-boxes and the like:
-
-   printf("%s",png_get_copyright(NULL));
-
-Also, the PNG logo (in PNG format, of course) is supplied in the
-files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
-
-Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is a
-certification mark of the Open Source Initiative.
-
-Glenn Randers-Pehrson
-glennrp at users.sourceforge.net
-March 29, 2012
diff --git a/extern/libpng/include/Makefile.am b/extern/libpng/include/Makefile.am
deleted file mode 100644
index 19652c4bda..0000000000
--- a/extern/libpng/include/Makefile.am
+++ /dev/null
@@ -1,228 +0,0 @@
-# Makefile.am:
-#   Source file for Makefile.in (and hence Makefile)
-#
-
-PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
-
-# libpng does not follow GNU file name conventions
-
-# "color-tests" requires automake 1.11.1 or later.  Enable it if you like,
-# to get red "FAIL" and green "PASS" notations during tests.
-# AUTOMAKE_OPTIONS = foreign color-tests
-AUTOMAKE_OPTIONS = foreign
-
-# test programs - run on make check, make distcheck
-TESTS_ENVIRONMENT= srcdir=$(srcdir)
-check_PROGRAMS= pngtest
-pngtest_SOURCES = pngtest.c
-pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-TESTS = test-pngtest.sh
-
-# Only do the following if the contrib directory is present.
-check_PROGRAMS+= pngvalid
-pngvalid_SOURCES = contrib/libtests/pngvalid.c
-pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-TESTS += test-pngvalid-simple.sh test-pngvalid-full.sh
-
-# man pages
-dist_man_MANS= libpng.3 libpngpf.3 png.5
-
-# generate the -config scripts if required
-binconfigs= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
-EXTRA_SCRIPTS= libpng-config libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
-bin_SCRIPTS= @binconfigs@
-
-# rules to build libpng, only build the old library on request
-lib_LTLIBRARIES=libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-# EXTRA_LTLIBRARIES= libpng.la
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c\
-	pngget.c pngmem.c pngpread.c pngread.c pngrio.c pngrtran.c pngrutil.c\
-	pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c\
-	png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h pngusr.dfa
-
-if PNG_ARM_NEON
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += arm/filter_neon.S
-endif
-
-nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
-
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_CPPFLAGS = @LIBPNG_DEFINES@
-
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined -export-dynamic \
-	-version-number @PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0
-
-if HAVE_LD_VERSION_SCRIPT
-#   Versioned symbols and restricted exports
-if HAVE_SOLARIS_LD
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,-M -Wl,libpng.vers
-else
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,--version-script=libpng.vers
-endif
-
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.vers
-else
-#   Only restricted exports when possible
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -export-symbols libpng.sym
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.sym
-endif
-
-#distribute headers in /usr/include/libpng/*
-pkgincludedir= $(includedir)/$(PNGLIB_BASENAME)
-pkginclude_HEADERS= png.h pngconf.h
-nodist_pkginclude_HEADERS= pnglibconf.h
-
-# pkg-config stuff, note that libpng.pc is always required in order
-# to get the correct library
-pkgconfigdir = @pkgconfigdir@
-pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc
-
-#extra source distribution files.
-EXTRA_DIST= \
-	ANNOUNCE CHANGES INSTALL LICENSE README TODO \
-	pngtest.png pngbar.png pngnow.png pngbar.jpg autogen.sh \
-	${srcdir}/contrib ${srcdir}/projects ${srcdir}/scripts \
-	$(TESTS) \
-	CMakeLists.txt example.c libpng-manual.txt
-
-SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk scripts/pnglibconf.dfn
-
-CLEANFILES= dfn.c dfn?.out pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
-	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
-	check.new pnglibconf.* symbols.new pngtest-log.txt \
-	$(SCRIPT_CLEANFILES)
-
-MAINTAINERCLEANFILES = Makefile.in aclocal.m4 config.guess config.h.in \
-config.sub configure depcomp install-sh ltmain.sh missing
-
-# DFNCPP is normally just CPP - the C preprocessor - but on Solaris and maybe
-# other operating systems (NeXT?) the C preprocessor selected by configure
-# checks input tokens for validity - effectively it performs part of the ANSI-C
-# parsing - and therefore fails with the .df files.  configure.ac has special
-# checks for this and sets DFNCPP appropriately.
-DFNCPP = @DFNCPP@
-
-SUFFIXES = .chk .dfn .out
-
-$(PNGLIB_BASENAME).pc: libpng.pc
-	cp libpng.pc $@
-
-$(PNGLIB_BASENAME)-config: libpng-config
-	cp libpng-config $@
-
-scripts/sym.out scripts/vers.out: png.h pngconf.h pnglibconf.h
-scripts/symbols.out: png.h pngconf.h $(srcdir)/scripts/pnglibconf.h.prebuilt
-
-libpng.sym: scripts/sym.out
-	rm -f $@
-	cp $? $@
-libpng.vers: scripts/vers.out
-	rm -f $@
-	cp $? $@
-pnglibconf.h: pnglibconf.out
-	rm -f $@
-	cp $? $@
-$(srcdir)/scripts/pnglibconf.h.prebuilt:
-	@echo "Attempting to build $@" >&2
-	@echo "This is a machine generated file, but if you want to make" >&2
-	@echo "a new one simply make 'scripts/pnglibconf.out' and copy that" >&2
-	@exit 1
-
-# The following is necessary to ensure that the local pnglibconf.h is used, not
-# an installed one (this can happen immediately after on a clean system if
-# 'make test' is the first thing the user does.)
-contrib/libtests/pngvalid.o pngtest.o: pnglibconf.h
-
-# We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
-# be built with PNG_USE_READ_MACROS; this prevents the read macros from
-# interfering with the symbol file format.
-SYMBOL_CFLAGS = -DPNGLIB_LIBNAME='PNG@PNGLIB_MAJOR@@PNGLIB_MINOR@_0'\
-		-DPNGLIB_VERSION='@PNGLIB_VERSION@'\
-		-DSYMBOL_PREFIX='$(SYMBOL_PREFIX)'\
-		-DPNG_NO_USE_READ_MACROS -DPNG_BUILDING_SYMBOL_TABLE
-
-.dfn.out:
-	rm -f $@ dfn.c dfn?.out
-	test -d scripts || mkdir scripts
-	echo '#include "$<"' >dfn.c
-	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) @LIBPNG_DEFINES@\
-	    $(CPPFLAGS) $(SYMBOL_CFLAGS) dfn.c > dfn1.out
-	$(SED) -n -e 's|^.*PNG_DEFN_MAGIC *-\(.*\)- *PNG_DEFN_END.*$$|\1|p'\
-	    dfn1.out >dfn2.out
-	$(SED) -e 's| *PNG_JOIN *||g' -e 's| *$$||' dfn2.out >dfn3.out
-	rm -f dfn.c dfn[12].out
-	mv dfn3.out $@
-
-# The .dfn file for pnglibconf.h is machine generated
-pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
-	rm -f $@ dfn?.out
-	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out version=search\
-	    ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
-	    ${srcdir}/pngusr.dfa $(DFA_XTRA) 1>&2
-	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn2.out dfn1.out 1>&2
-	rm dfn1.out
-	mv dfn2.out $@
-
-# Symbol checks (.def and .out files should match)
-scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.out
-.out.chk:
-	rm -f $@ symbols.new
-	$(AWK) -f ${srcdir}/scripts/checksym.awk ${srcdir}/scripts/${*F}.def\
-	    $< >&2
-	mv symbols.new $@
-
-# used on demand to regenerate the standard header, CPPFLAGS should
-# be empty - no non-standard defines
-scripts/pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
-	rm -f $@ dfn?.out
-	test -z "$(CPPFLAGS)"
-	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
-	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out logunsupported=1
-		version=search ${srcdir}/pngconf.h -\
-		${srcdir}/scripts/pnglibconf.dfa 1>&2
-	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn2.out dfn1.out 1>&2
-	rm dfn1.out
-	mv dfn2.out $@
-
-$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS): png.h pngconf.h \
-	pnglibconf.h pngpriv.h pngdebug.h pnginfo.h pngstruct.h
-
-test: check-am
-
-# Extra checks
-check: scripts/symbols.chk
-
-# Don't distribute the generated script files
-dist-hook:
-	cd '$(top_distdir)'; rm -f $(SCRIPT_CLEANFILES)
-
-# install the .../include headers as links to the new ones
-install-data-hook:
-	cd $(DESTDIR)$(includedir); rm -f png.h pngconf.h pnglibconf.h
-	cd $(DESTDIR)$(includedir); $(LN_S) $(PNGLIB_BASENAME)/png.h png.h
-	cd $(DESTDIR)$(includedir); $(LN_S) $(PNGLIB_BASENAME)/pngconf.h \
-		pngconf.h
-	cd $(DESTDIR)$(includedir); $(LN_S) $(PNGLIB_BASENAME)/pnglibconf.h \
-		pnglibconf.h
-	cd $(DESTDIR)$(pkgconfigdir); rm -f libpng.pc
-	cd $(DESTDIR)$(pkgconfigdir); $(LN_S) $(PNGLIB_BASENAME).pc libpng.pc
-
-# do evil things to libpng to cause libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ to be used
-install-exec-hook:
-	cd $(DESTDIR)$(bindir); rm -f libpng-config
-	cd $(DESTDIR)$(bindir); $(LN_S) $(PNGLIB_BASENAME)-config libpng-config
-	@set -x;\
-	cd $(DESTDIR)$(libdir);\
-	for ext in a la so so.@PNGLIB_MAJOR@@PNGLIB_MINOR@.@PNGLIB_RELEASE@ sl dylib dll.a; do\
-		rm -f libpng.$$ext;\
-                if test -f $(PNGLIB_BASENAME).$$ext; then\
-                       $(LN_S) $(PNGLIB_BASENAME).$$ext libpng.$$ext;\
-                fi;\
-	done
-
-uninstall-hook:
-	cd $(DESTDIR)$(includedir); rm -f png.h pngconf.h pnglibconf.h
-	rm -f $(DESTDIR)$(pkgconfigdir)/libpng.pc
-	rm -f $(DESTDIR)$(bindir)/libpng-config
-	rm -f $(DESTDIR)$(libdir)/libpng.a
-	rm -f $(DESTDIR)$(libdir)/libpng.la
-	rm -f $(DESTDIR)$(libdir)/libpng.dll.a
diff --git a/extern/libpng/include/README b/extern/libpng/include/README
deleted file mode 100644
index e821ee4c87..0000000000
--- a/extern/libpng/include/README
+++ /dev/null
@@ -1,202 +0,0 @@
-README for libpng version 1.5.10 - March 29, 2012 (shared library 15.0)
-See the note about version numbers near the top of png.h
-
-See INSTALL for instructions on how to install libpng.
-
-Libpng comes in several distribution formats.  Get libpng-*.tar.gz,
-libpng-*.tar.xz or libpng-*.tar.bz2 if you want UNIX-style line endings
-in the text files, or lpng*.zip if you want DOS-style line endings.
-
-Version 0.89 was the first official release of libpng.  Don't let the
-fact that it's the first release fool you.  The libpng library has been in
-extensive use and testing since mid-1995.  By late 1997 it had
-finally gotten to the stage where there hadn't been significant
-changes to the API in some time, and people have a bad feeling about
-libraries with versions < 1.0.  Version 1.0.0 was released in
-March 1998.
-
-****
-Note that some of the changes to the png_info structure render this
-version of the library binary incompatible with libpng-0.89 or
-earlier versions if you are using a shared library.  The type of the
-"filler" parameter for png_set_filler() has changed from png_byte to
-png_uint_32, which will affect shared-library applications that use
-this function.
-
-To avoid problems with changes to the internals of png_info_struct,
-new APIs have been made available in 0.95 to avoid direct application
-access to info_ptr.  These functions are the png_set_<chunk> and
-png_get_<chunk> functions.  These functions should be used when
-accessing/storing the info_struct data, rather than manipulating it
-directly, to avoid such problems in the future.
-
-It is important to note that the APIs do not make current programs
-that access the info struct directly incompatible with the new
-library.  However, it is strongly suggested that new programs use
-the new APIs (as shown in example.c and pngtest.c), and older programs
-be converted to the new format, to facilitate upgrades in the future.
-****
-
-Additions since 0.90 include the ability to compile libpng as a
-Windows DLL, and new APIs for accessing data in the info struct.
-Experimental functions include the ability to set weighting and cost
-factors for row filter selection, direct reads of integers from buffers
-on big-endian processors that support misaligned data access, faster
-methods of doing alpha composition, and more accurate 16->8 bit color
-conversion.
-
-The additions since 0.89 include the ability to read from a PNG stream
-which has had some (or all) of the signature bytes read by the calling
-application.  This also allows the reading of embedded PNG streams that
-do not have the PNG file signature.  As well, it is now possible to set
-the library action on the detection of chunk CRC errors.  It is possible
-to set different actions based on whether the CRC error occurred in a
-critical or an ancillary chunk.
-
-The changes made to the library, and bugs fixed are based on discussions
-on the PNG-implement mailing list and not on material submitted
-privately to Guy, Andreas, or Glenn.  They will forward any good
-suggestions to the list.
-
-For a detailed description on using libpng, read libpng-manual.txt.  For
-examples of libpng in a program, see example.c and pngtest.c.  For usage
-information and restrictions (what little they are) on libpng, see
-png.h.  For a description on using zlib (the compression library used by
-libpng) and zlib's restrictions, see zlib.h
-
-I have included a general makefile, as well as several machine and
-compiler specific ones, but you may have to modify one for your own needs.
-
-You should use zlib 1.0.4 or later to run this, but it MAY work with
-versions as old as zlib 0.95.  Even so, there are bugs in older zlib
-versions which can cause the output of invalid compression streams for
-some images.  You will definitely need zlib 1.0.4 or later if you are
-taking advantage of the MS-DOS "far" structure allocation for the small
-and medium memory models.  You should also note that zlib is a
-compression library that is useful for more things than just PNG files.
-You can use zlib as a drop-in replacement for fread() and fwrite() if
-you are so inclined.
-
-zlib should be available at the same place that libpng is, or at.
-ftp://ftp.info-zip.org/pub/infozip/zlib
-
-You may also want a copy of the PNG specification.  It is available
-as an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find
-these at http://www.libpng.org/pub/png/documents/
-
-This code is currently being archived at libpng.sf.net in the
-[DOWNLOAD] area, and on CompuServe, Lib 20 (PNG SUPPORT)
-at GO GRAPHSUP.  If you can't find it in any of those places,
-e-mail me, and I'll help you find it.
-
-If you have any code changes, requests, problems, etc., please e-mail
-them to me.  Also, I'd appreciate any make files or project files,
-and any modifications you needed to make to get libpng to compile,
-along with a #define variable to tell what compiler/system you are on.
-If you needed to add transformations to libpng, or wish libpng would
-provide the image in a different way, drop me a note (and code, if
-possible), so I can consider supporting the transformation.
-Finally, if you get any warning messages when compiling libpng
-(note: not zlib), and they are easy to fix, I'd appreciate the
-fix.  Please mention "libpng" somewhere in the subject line.  Thanks.
-
-This release was created and will be supported by myself (of course
-based in a large way on Guy's and Andreas' earlier work), and the PNG
-development group.
-
-Send comments/corrections/commendations to png-mng-implement at
-lists.sourceforge.net (subscription required; visit 
-https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe) or to glennrp at users.sourceforge.net
-
-You can't reach Guy, the original libpng author, at the addresses
-given in previous versions of this document.  He and Andreas will
-read mail addressed to the png-implement list, however.
-
-Please do not send general questions about PNG.  Send them to
-png-mng-misc at lists.sf.net (subscription required; visit
-https://lists.sourceforge.net/lists/listinfo/png-mng-misc to
-subscribe).  If you have a question about something
-in the PNG specification that is related to using libpng, send it
-to me.  Send me any questions that start with "I was using libpng,
-and ...".  If in doubt, send questions to me.  I'll bounce them
-to others, if necessary.
-
-Please do not send suggestions on how to change PNG.  We have
-been discussing PNG for sixteen years now, and it is official and
-finished.  If you have suggestions for libpng, however, I'll
-gladly listen.  Even if your suggestion is not used immediately,
-it may be used later.
-
-Files in this distribution:
-
-      ANNOUNCE      =>  Announcement of this version, with recent changes
-      CHANGES       =>  Description of changes between libpng versions
-      KNOWNBUG      =>  List of known bugs and deficiencies
-      LICENSE       =>  License to use and redistribute libpng
-      README        =>  This file
-      TODO          =>  Things not implemented in the current library
-      Y2KINFO       =>  Statement of Y2K compliance
-      example.c     =>  Example code for using libpng functions
-      libpng.3      =>  manual page for libpng (includes libpng-manual.txt)
-      libpng-manual.txt  =>  Description of libpng and its functions
-      libpngpf.3    =>  manual page for libpng's private functions
-      png.5         =>  manual page for the PNG format
-      png.c         =>  Basic interface functions common to library
-      png.h         =>  Library function and interface declarations (public)
-      pngpriv.h     =>  Library function and interface declarations (private)
-      pngconf.h     =>  System specific library configuration (public)
-      pngstruct.h   =>  png_struct declaration (private)
-      pnginfo.h     =>  png_info struct declaration (private)
-      pngdebug.h    =>  debugging macros (private)
-      pngerror.c    =>  Error/warning message I/O functions
-      pngget.c      =>  Functions for retrieving info from struct
-      pngmem.c      =>  Memory handling functions
-      pngbar.png    =>  PNG logo, 88x31
-      pngnow.png    =>  PNG logo, 98x31
-      pngpread.c    =>  Progressive reading functions
-      pngread.c     =>  Read data/helper high-level functions
-      pngrio.c      =>  Lowest-level data read I/O functions
-      pngrtran.c    =>  Read data transformation functions
-      pngrutil.c    =>  Read data utility functions
-      pngset.c      =>  Functions for storing data into the info_struct
-      pngtest.c     =>  Library test program
-      pngtest.png   =>  Library test sample image
-      pngtrans.c    =>  Common data transformation functions
-      pngwio.c      =>  Lowest-level write I/O functions
-      pngwrite.c    =>  High-level write functions
-      pngwtran.c    =>  Write data transformations
-      pngwutil.c    =>  Write utility functions
-      contrib       =>  Contributions
-       gregbook         =>  source code for PNG reading and writing, from
-                            Greg Roelofs' "PNG: The Definitive Guide",
-                            O'Reilly, 1999
-       msvctest     =>  Builds and runs pngtest using a MSVC workspace
-       pngminus     =>  Simple pnm2png and png2pnm programs
-       pngsuite     =>  Test images
-       visupng      =>  Contains a MSVC workspace for VisualPng
-      projects      =>  Contains project files and workspaces for
-                        building a DLL
-       cbuilder5        =>  Contains a Borland workspace for building
-                            libpng and zlib
-       visualc6         =>  Contains a Microsoft Visual C++ (MSVC)
-                            workspace for building libpng and zlib
-       visualc71        =>  Contains a Microsoft Visual C++ (MSVC)
-                            workspace for building libpng and zlib
-       xcode            =>  Contains an Apple xcode
-                            workspace for building libpng and zlib
-      scripts       =>  Directory containing scripts for building libpng:
-                            (see scripts/README.txt for the list of scripts)
-
-Good luck, and happy coding.
-
--Glenn Randers-Pehrson (current maintainer, since 1998)
- Internet: glennrp at users.sourceforge.net
-
--Andreas Eric Dilger (former maintainer, 1996-1997)
- Internet: adilger at enel.ucalgary.ca
- Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/
-
--Guy Eric Schalnat (original author and former maintainer, 1995-1996)
- (formerly of Group 42, Inc)
- Internet: gschal at infinet.com
diff --git a/extern/libpng/include/TODO b/extern/libpng/include/TODO
deleted file mode 100644
index 6e1f028bd7..0000000000
--- a/extern/libpng/include/TODO
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
-TODO - list of things to do for libpng:
-
-Final bug fixes.
-Better C++ wrapper/full C++ implementation?
-Fix problem with C++ and EXTERN "C".
-cHRM transformation.
-Remove setjmp/longjmp usage in favor of returning error codes.
-Add "grayscale->palette" transformation and "palette->grayscale" detection.
-Improved dithering.
-Multi-lingual error and warning message support.
-Complete sRGB transformation (presently it simply uses gamma=0.45455).
-Man pages for function calls.
-Better documentation.
-Better filter selection
-   (counting huffman bits/precompression?  filter inertia?  filter costs?).
-Histogram creation.
-Text conversion between different code pages (Latin-1 -> Mac and DOS).
-Avoid building gamma tables whenever possible.
-Use greater precision when changing to linear gamma for compositing against
-  background and doing rgb-to-gray transformation.
-Investigate pre-incremented loop counters and other loop constructions.
-Add interpolated method of handling interlacing.
-Switch to the simpler zlib (zlib/libpng) license if legally possible.
-Extend pngvalid.c to validate more of the libpng transformations.
-
-*/
diff --git a/extern/libpng/include/autogen.sh b/extern/libpng/include/autogen.sh
deleted file mode 100755
index 5be104eb1d..0000000000
--- a/extern/libpng/include/autogen.sh
+++ /dev/null
@@ -1,34 +0,0 @@
-#! /bin/sh
-# a quick hack script to generate necessary files from 
-# auto* tools.
-#
-# WARNING: if you run this you will change the versions
-# of the tools which are used and, maybe, required!
-
-# You can define your own replacements in your environment.
-# $AUTOCONF,  $AUTOMAKE, $AUTOHEADER, $AUTOPOINT, $ACLOCAL and $LIBTOOLIZE
-
-touch Makefile.am configure.ac
-{
-   LT=${LIBTOOLIZE-libtoolize}
-   echo "running $LT" >&2
-   $LT --force --copy --automake
-} && {
-   AL=${ACLOCAL-aclocal}
-   echo "running $AL" >&2
-   $AL
-} && {
-   AH=${AUTOHEADER-autoheader}
-   echo "running $AH [ignore the warnings]" >&2
-   $AH
-} && {
-   AM=${AUTOMAKE-automake}
-   echo "running $AM" >&2
-   $AM --force-missing --foreign -a -c
-} && {
-   AC=${AUTOCONF-autoconf}
-   echo "running $AC" >&2
-   $AC
-} &&
-   echo "autogen complete" >&2 ||
-   echo "ERROR: autogen.sh failed, autogen is incomplete" >&2
diff --git a/extern/libpng/include/config.guess b/extern/libpng/include/config.guess
deleted file mode 100644
index 8152efd675..0000000000
--- a/extern/libpng/include/config.guess
+++ /dev/null
@@ -1,1522 +0,0 @@
-#! /bin/sh
-# Attempt to guess a canonical system name.
-#   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
-#   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
-#   2011 Free Software Foundation, Inc.
-
-timestamp='2011-11-11'
-
-# This file is free software; you can redistribute it and/or modify it
-# under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful, but
-# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
-# 02110-1301, USA.
-#
-# As a special exception to the GNU General Public License, if you
-# distribute this file as part of a program that contains a
-# configuration script generated by Autoconf, you may include it under
-# the same distribution terms that you use for the rest of that program.
-
-
-# Originally written by Per Bothner.  Please send patches (context
-# diff format) to <config-patches@gnu.org> and include a ChangeLog
-# entry.
-#
-# This script attempts to guess a canonical system name similar to
-# config.sub.  If it succeeds, it prints the system name on stdout, and
-# exits with 0.  Otherwise, it exits with 1.
-#
-# You can get the latest version of this script from:
-# http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD
-
-me=`echo "$0" | sed -e 's,.*/,,'`
-
-usage="\
-Usage: $0 [OPTION]
-
-Output the configuration name of the system \`$me' is run on.
-
-Operation modes:
-  -h, --help         print this help, then exit
-  -t, --time-stamp   print date of last modification, then exit
-  -v, --version      print version number, then exit
-
-Report bugs and patches to <config-patches@gnu.org>."
-
-version="\
-GNU config.guess ($timestamp)
-
-Originally written by Per Bothner.
-Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free
-Software Foundation, Inc.
-
-This is free software; see the source for copying conditions.  There is NO
-warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
-
-help="
-Try \`$me --help' for more information."
-
-# Parse command line
-while test $# -gt 0 ; do
-  case $1 in
-    --time-stamp | --time* | -t )
-       echo "$timestamp" ; exit ;;
-    --version | -v )
-       echo "$version" ; exit ;;
-    --help | --h* | -h )
-       echo "$usage"; exit ;;
-    -- )     # Stop option processing
-       shift; break ;;
-    - )	# Use stdin as input.
-       break ;;
-    -* )
-       echo "$me: invalid option $1$help" >&2
-       exit 1 ;;
-    * )
-       break ;;
-  esac
-done
-
-if test $# != 0; then
-  echo "$me: too many arguments$help" >&2
-  exit 1
-fi
-
-trap 'exit 1' 1 2 15
-
-# CC_FOR_BUILD -- compiler used by this script. Note that the use of a
-# compiler to aid in system detection is discouraged as it requires
-# temporary files to be created and, as you can see below, it is a
-# headache to deal with in a portable fashion.
-
-# Historically, `CC_FOR_BUILD' used to be named `HOST_CC'. We still
-# use `HOST_CC' if defined, but it is deprecated.
-
-# Portable tmp directory creation inspired by the Autoconf team.
-
-set_cc_for_build='
-trap "exitcode=\$?; (rm -f \$tmpfiles 2>/dev/null; rmdir \$tmp 2>/dev/null) && exit \$exitcode" 0 ;
-trap "rm -f \$tmpfiles 2>/dev/null; rmdir \$tmp 2>/dev/null; exit 1" 1 2 13 15 ;
-: ${TMPDIR=/tmp} ;
- { tmp=`(umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null` && test -n "$tmp" && test -d "$tmp" ; } ||
- { test -n "$RANDOM" && tmp=$TMPDIR/cg$$-$RANDOM && (umask 077 && mkdir $tmp) ; } ||
- { tmp=$TMPDIR/cg-$$ && (umask 077 && mkdir $tmp) && echo "Warning: creating insecure temp directory" >&2 ; } ||
- { echo "$me: cannot create a temporary directory in $TMPDIR" >&2 ; exit 1 ; } ;
-dummy=$tmp/dummy ;
-tmpfiles="$dummy.c $dummy.o $dummy.rel $dummy" ;
-case $CC_FOR_BUILD,$HOST_CC,$CC in
- ,,)    echo "int x;" > $dummy.c ;
-	for c in cc gcc c89 c99 ; do
-	  if ($c -c -o $dummy.o $dummy.c) >/dev/null 2>&1 ; then
-	     CC_FOR_BUILD="$c"; break ;
-	  fi ;
-	done ;
-	if test x"$CC_FOR_BUILD" = x ; then
-	  CC_FOR_BUILD=no_compiler_found ;
-	fi
-	;;
- ,,*)   CC_FOR_BUILD=$CC ;;
- ,*,*)  CC_FOR_BUILD=$HOST_CC ;;
-esac ; set_cc_for_build= ;'
-
-# This is needed to find uname on a Pyramid OSx when run in the BSD universe.
-# (ghazi@noc.rutgers.edu 1994-08-24)
-if (test -f /.attbin/uname) >/dev/null 2>&1 ; then
-	PATH=$PATH:/.attbin ; export PATH
-fi
-
-UNAME_MACHINE=`(uname -m) 2>/dev/null` || UNAME_MACHINE=unknown
-UNAME_RELEASE=`(uname -r) 2>/dev/null` || UNAME_RELEASE=unknown
-UNAME_SYSTEM=`(uname -s) 2>/dev/null`  || UNAME_SYSTEM=unknown
-UNAME_VERSION=`(uname -v) 2>/dev/null` || UNAME_VERSION=unknown
-
-# Note: order is significant - the case branches are not exclusive.
-
-case "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" in
-    *:NetBSD:*:*)
-	# NetBSD (nbsd) targets should (where applicable) match one or
-	# more of the tupples: *-*-netbsdelf*, *-*-netbsdaout*,
-	# *-*-netbsdecoff* and *-*-netbsd*.  For targets that recently
-	# switched to ELF, *-*-netbsd* would select the old
-	# object file format.  This provides both forward
-	# compatibility and a consistent mechanism for selecting the
-	# object file format.
-	#
-	# Note: NetBSD doesn't particularly care about the vendor
-	# portion of the name.  We always set it to "unknown".
-	sysctl="sysctl -n hw.machine_arch"
-	UNAME_MACHINE_ARCH=`(/sbin/$sysctl 2>/dev/null || \
-	    /usr/sbin/$sysctl 2>/dev/null || echo unknown)`
-	case "${UNAME_MACHINE_ARCH}" in
-	    armeb) machine=armeb-unknown ;;
-	    arm*) machine=arm-unknown ;;
-	    sh3el) machine=shl-unknown ;;
-	    sh3eb) machine=sh-unknown ;;
-	    sh5el) machine=sh5le-unknown ;;
-	    *) machine=${UNAME_MACHINE_ARCH}-unknown ;;
-	esac
-	# The Operating System including object format, if it has switched
-	# to ELF recently, or will in the future.
-	case "${UNAME_MACHINE_ARCH}" in
-	    arm*|i386|m68k|ns32k|sh3*|sparc|vax)
-		eval $set_cc_for_build
-		if echo __ELF__ | $CC_FOR_BUILD -E - 2>/dev/null \
-			| grep -q __ELF__
-		then
-		    # Once all utilities can be ECOFF (netbsdecoff) or a.out (netbsdaout).
-		    # Return netbsd for either.  FIX?
-		    os=netbsd
-		else
-		    os=netbsdelf
-		fi
-		;;
-	    *)
-		os=netbsd
-		;;
-	esac
-	# The OS release
-	# Debian GNU/NetBSD machines have a different userland, and
-	# thus, need a distinct triplet. However, they do not need
-	# kernel version information, so it can be replaced with a
-	# suitable tag, in the style of linux-gnu.
-	case "${UNAME_VERSION}" in
-	    Debian*)
-		release='-gnu'
-		;;
-	    *)
-		release=`echo ${UNAME_RELEASE}|sed -e 's/[-_].*/\./'`
-		;;
-	esac
-	# Since CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM:
-	# contains redundant information, the shorter form:
-	# CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM is used.
-	echo "${machine}-${os}${release}"
-	exit ;;
-    *:OpenBSD:*:*)
-	UNAME_MACHINE_ARCH=`arch | sed 's/OpenBSD.//'`
-	echo ${UNAME_MACHINE_ARCH}-unknown-openbsd${UNAME_RELEASE}
-	exit ;;
-    *:ekkoBSD:*:*)
-	echo ${UNAME_MACHINE}-unknown-ekkobsd${UNAME_RELEASE}
-	exit ;;
-    *:SolidBSD:*:*)
-	echo ${UNAME_MACHINE}-unknown-solidbsd${UNAME_RELEASE}
-	exit ;;
-    macppc:MirBSD:*:*)
-	echo powerpc-unknown-mirbsd${UNAME_RELEASE}
-	exit ;;
-    *:MirBSD:*:*)
-	echo ${UNAME_MACHINE}-unknown-mirbsd${UNAME_RELEASE}
-	exit ;;
-    alpha:OSF1:*:*)
-	case $UNAME_RELEASE in
-	*4.0)
-		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $3}'`
-		;;
-	*5.*)
-		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $4}'`
-		;;
-	esac
-	# According to Compaq, /usr/sbin/psrinfo has been available on
-	# OSF/1 and Tru64 systems produced since 1995.  I hope that
-	# covers most systems running today.  This code pipes the CPU
-	# types through head -n 1, so we only detect the type of CPU 0.
-	ALPHA_CPU_TYPE=`/usr/sbin/psrinfo -v | sed -n -e 's/^  The alpha \(.*\) processor.*$/\1/p' | head -n 1`
-	case "$ALPHA_CPU_TYPE" in
-	    "EV4 (21064)")
-		UNAME_MACHINE="alpha" ;;
-	    "EV4.5 (21064)")
-		UNAME_MACHINE="alpha" ;;
-	    "LCA4 (21066/21068)")
-		UNAME_MACHINE="alpha" ;;
-	    "EV5 (21164)")
-		UNAME_MACHINE="alphaev5" ;;
-	    "EV5.6 (21164A)")
-		UNAME_MACHINE="alphaev56" ;;
-	    "EV5.6 (21164PC)")
-		UNAME_MACHINE="alphapca56" ;;
-	    "EV5.7 (21164PC)")
-		UNAME_MACHINE="alphapca57" ;;
-	    "EV6 (21264)")
-		UNAME_MACHINE="alphaev6" ;;
-	    "EV6.7 (21264A)")
-		UNAME_MACHINE="alphaev67" ;;
-	    "EV6.8CB (21264C)")
-		UNAME_MACHINE="alphaev68" ;;
-	    "EV6.8AL (21264B)")
-		UNAME_MACHINE="alphaev68" ;;
-	    "EV6.8CX (21264D)")
-		UNAME_MACHINE="alphaev68" ;;
-	    "EV6.9A (21264/EV69A)")
-		UNAME_MACHINE="alphaev69" ;;
-	    "EV7 (21364)")
-		UNAME_MACHINE="alphaev7" ;;
-	    "EV7.9 (21364A)")
-		UNAME_MACHINE="alphaev79" ;;
-	esac
-	# A Pn.n version is a patched version.
-	# A Vn.n version is a released version.
-	# A Tn.n version is a released field test version.
-	# A Xn.n version is an unreleased experimental baselevel.
-	# 1.2 uses "1.2" for uname -r.
-	echo ${UNAME_MACHINE}-dec-osf`echo ${UNAME_RELEASE} | sed -e 's/^[PVTX]//' | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz'`
-	# Reset EXIT trap before exiting to avoid spurious non-zero exit code.
-	exitcode=$?
-	trap '' 0
-	exit $exitcode ;;
-    Alpha\ *:Windows_NT*:*)
-	# How do we know it's Interix rather than the generic POSIX subsystem?
-	# Should we change UNAME_MACHINE based on the output of uname instead
-	# of the specific Alpha model?
-	echo alpha-pc-interix
-	exit ;;
-    21064:Windows_NT:50:3)
-	echo alpha-dec-winnt3.5
-	exit ;;
-    Amiga*:UNIX_System_V:4.0:*)
-	echo m68k-unknown-sysv4
-	exit ;;
-    *:[Aa]miga[Oo][Ss]:*:*)
-	echo ${UNAME_MACHINE}-unknown-amigaos
-	exit ;;
-    *:[Mm]orph[Oo][Ss]:*:*)
-	echo ${UNAME_MACHINE}-unknown-morphos
-	exit ;;
-    *:OS/390:*:*)
-	echo i370-ibm-openedition
-	exit ;;
-    *:z/VM:*:*)
-	echo s390-ibm-zvmoe
-	exit ;;
-    *:OS400:*:*)
-	echo powerpc-ibm-os400
-	exit ;;
-    arm:RISC*:1.[012]*:*|arm:riscix:1.[012]*:*)
-	echo arm-acorn-riscix${UNAME_RELEASE}
-	exit ;;
-    arm:riscos:*:*|arm:RISCOS:*:*)
-	echo arm-unknown-riscos
-	exit ;;
-    SR2?01:HI-UX/MPP:*:* | SR8000:HI-UX/MPP:*:*)
-	echo hppa1.1-hitachi-hiuxmpp
-	exit ;;
-    Pyramid*:OSx*:*:* | MIS*:OSx*:*:* | MIS*:SMP_DC-OSx*:*:*)
-	# akee@wpdis03.wpafb.af.mil (Earle F. Ake) contributed MIS and NILE.
-	if test "`(/bin/universe) 2>/dev/null`" = att ; then
-		echo pyramid-pyramid-sysv3
-	else
-		echo pyramid-pyramid-bsd
-	fi
-	exit ;;
-    NILE*:*:*:dcosx)
-	echo pyramid-pyramid-svr4
-	exit ;;
-    DRS?6000:unix:4.0:6*)
-	echo sparc-icl-nx6
-	exit ;;
-    DRS?6000:UNIX_SV:4.2*:7* | DRS?6000:isis:4.2*:7*)
-	case `/usr/bin/uname -p` in
-	    sparc) echo sparc-icl-nx7; exit ;;
-	esac ;;
-    s390x:SunOS:*:*)
-	echo ${UNAME_MACHINE}-ibm-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
-	exit ;;
-    sun4H:SunOS:5.*:*)
-	echo sparc-hal-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
-	exit ;;
-    sun4*:SunOS:5.*:* | tadpole*:SunOS:5.*:*)
-	echo sparc-sun-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
-	exit ;;
-    i86pc:AuroraUX:5.*:* | i86xen:AuroraUX:5.*:*)
-	echo i386-pc-auroraux${UNAME_RELEASE}
-	exit ;;
-    i86pc:SunOS:5.*:* | i86xen:SunOS:5.*:*)
-	eval $set_cc_for_build
-	SUN_ARCH="i386"
-	# If there is a compiler, see if it is configured for 64-bit objects.
-	# Note that the Sun cc does not turn __LP64__ into 1 like gcc does.
-	# This test works for both compilers.
-	if [ "$CC_FOR_BUILD" != 'no_compiler_found' ]; then
-	    if (echo '#ifdef __amd64'; echo IS_64BIT_ARCH; echo '#endif') | \
-		(CCOPTS= $CC_FOR_BUILD -E - 2>/dev/null) | \
-		grep IS_64BIT_ARCH >/dev/null
-	    then
-		SUN_ARCH="x86_64"
-	    fi
-	fi
-	echo ${SUN_ARCH}-pc-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
-	exit ;;
-    sun4*:SunOS:6*:*)
-	# According to config.sub, this is the proper way to canonicalize
-	# SunOS6.  Hard to guess exactly what SunOS6 will be like, but
-	# it's likely to be more like Solaris than SunOS4.
-	echo sparc-sun-solaris3`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
-	exit ;;
-    sun4*:SunOS:*:*)
-	case "`/usr/bin/arch -k`" in
-	    Series*|S4*)
-		UNAME_RELEASE=`uname -v`
-		;;
-	esac
-	# Japanese Language versions have a version number like `4.1.3-JL'.
-	echo sparc-sun-sunos`echo ${UNAME_RELEASE}|sed -e 's/-/_/'`
-	exit ;;
-    sun3*:SunOS:*:*)
-	echo m68k-sun-sunos${UNAME_RELEASE}
-	exit ;;
-    sun*:*:4.2BSD:*)
-	UNAME_RELEASE=`(sed 1q /etc/motd | awk '{print substr($5,1,3)}') 2>/dev/null`
-	test "x${UNAME_RELEASE}" = "x" && UNAME_RELEASE=3
-	case "`/bin/arch`" in
-	    sun3)
-		echo m68k-sun-sunos${UNAME_RELEASE}
-		;;
-	    sun4)
-		echo sparc-sun-sunos${UNAME_RELEASE}
-		;;
-	esac
-	exit ;;
-    aushp:SunOS:*:*)
-	echo sparc-auspex-sunos${UNAME_RELEASE}
-	exit ;;
-    # The situation for MiNT is a little confusing.  The machine name
-    # can be virtually everything (everything which is not
-    # "atarist" or "atariste" at least should have a processor
-    # > m68000).  The system name ranges from "MiNT" over "FreeMiNT"
-    # to the lowercase version "mint" (or "freemint").  Finally
-    # the system name "TOS" denotes a system which is actually not
-    # MiNT.  But MiNT is downward compatible to TOS, so this should
-    # be no problem.
-    atarist[e]:*MiNT:*:* | atarist[e]:*mint:*:* | atarist[e]:*TOS:*:*)
-	echo m68k-atari-mint${UNAME_RELEASE}
-	exit ;;
-    atari*:*MiNT:*:* | atari*:*mint:*:* | atarist[e]:*TOS:*:*)
-	echo m68k-atari-mint${UNAME_RELEASE}
-	exit ;;
-    *falcon*:*MiNT:*:* | *falcon*:*mint:*:* | *falcon*:*TOS:*:*)
-	echo m68k-atari-mint${UNAME_RELEASE}
-	exit ;;
-    milan*:*MiNT:*:* | milan*:*mint:*:* | *milan*:*TOS:*:*)
-	echo m68k-milan-mint${UNAME_RELEASE}
-	exit ;;
-    hades*:*MiNT:*:* | hades*:*mint:*:* | *hades*:*TOS:*:*)
-	echo m68k-hades-mint${UNAME_RELEASE}
-	exit ;;
-    *:*MiNT:*:* | *:*mint:*:* | *:*TOS:*:*)
-	echo m68k-unknown-mint${UNAME_RELEASE}
-	exit ;;
-    m68k:machten:*:*)
-	echo m68k-apple-machten${UNAME_RELEASE}
-	exit ;;
-    powerpc:machten:*:*)
-	echo powerpc-apple-machten${UNAME_RELEASE}
-	exit ;;
-    RISC*:Mach:*:*)
-	echo mips-dec-mach_bsd4.3
-	exit ;;
-    RISC*:ULTRIX:*:*)
-	echo mips-dec-ultrix${UNAME_RELEASE}
-	exit ;;
-    VAX*:ULTRIX*:*:*)
-	echo vax-dec-ultrix${UNAME_RELEASE}
-	exit ;;
-    2020:CLIX:*:* | 2430:CLIX:*:*)
-	echo clipper-intergraph-clix${UNAME_RELEASE}
-	exit ;;
-    mips:*:*:UMIPS | mips:*:*:RISCos)
-	eval $set_cc_for_build
-	sed 's/^	//' << EOF >$dummy.c
-#ifdef __cplusplus
-#include <stdio.h>  /* for printf() prototype */
-	int main (int argc, char *argv[]) {
-#else
-	int main (argc, argv) int argc; char *argv[]; {
-#endif
-	#if defined (host_mips) && defined (MIPSEB)
-	#if defined (SYSTYPE_SYSV)
-	  printf ("mips-mips-riscos%ssysv\n", argv[1]); exit (0);
-	#endif
-	#if defined (SYSTYPE_SVR4)
-	  printf ("mips-mips-riscos%ssvr4\n", argv[1]); exit (0);
-	#endif
-	#if defined (SYSTYPE_BSD43) || defined(SYSTYPE_BSD)
-	  printf ("mips-mips-riscos%sbsd\n", argv[1]); exit (0);
-	#endif
-	#endif
-	  exit (-1);
-	}
-EOF
-	$CC_FOR_BUILD -o $dummy $dummy.c &&
-	  dummyarg=`echo "${UNAME_RELEASE}" | sed -n 's/\([0-9]*\).*/\1/p'` &&
-	  SYSTEM_NAME=`$dummy $dummyarg` &&
-	    { echo "$SYSTEM_NAME"; exit; }
-	echo mips-mips-riscos${UNAME_RELEASE}
-	exit ;;
-    Motorola:PowerMAX_OS:*:*)
-	echo powerpc-motorola-powermax
-	exit ;;
-    Motorola:*:4.3:PL8-*)
-	echo powerpc-harris-powermax
-	exit ;;
-    Night_Hawk:*:*:PowerMAX_OS | Synergy:PowerMAX_OS:*:*)
-	echo powerpc-harris-powermax
-	exit ;;
-    Night_Hawk:Power_UNIX:*:*)
-	echo powerpc-harris-powerunix
-	exit ;;
-    m88k:CX/UX:7*:*)
-	echo m88k-harris-cxux7
-	exit ;;
-    m88k:*:4*:R4*)
-	echo m88k-motorola-sysv4
-	exit ;;
-    m88k:*:3*:R3*)
-	echo m88k-motorola-sysv3
-	exit ;;
-    AViiON:dgux:*:*)
-	# DG/UX returns AViiON for all architectures
-	UNAME_PROCESSOR=`/usr/bin/uname -p`
-	if [ $UNAME_PROCESSOR = mc88100 ] || [ $UNAME_PROCESSOR = mc88110 ]
-	then
-	    if [ ${TARGET_BINARY_INTERFACE}x = m88kdguxelfx ] || \
-	       [ ${TARGET_BINARY_INTERFACE}x = x ]
-	    then
-		echo m88k-dg-dgux${UNAME_RELEASE}
-	    else
-		echo m88k-dg-dguxbcs${UNAME_RELEASE}
-	    fi
-	else
-	    echo i586-dg-dgux${UNAME_RELEASE}
-	fi
-	exit ;;
-    M88*:DolphinOS:*:*)	# DolphinOS (SVR3)
-	echo m88k-dolphin-sysv3
-	exit ;;
-    M88*:*:R3*:*)
-	# Delta 88k system running SVR3
-	echo m88k-motorola-sysv3
-	exit ;;
-    XD88*:*:*:*) # Tektronix XD88 system running UTekV (SVR3)
-	echo m88k-tektronix-sysv3
-	exit ;;
-    Tek43[0-9][0-9]:UTek:*:*) # Tektronix 4300 system running UTek (BSD)
-	echo m68k-tektronix-bsd
-	exit ;;
-    *:IRIX*:*:*)
-	echo mips-sgi-irix`echo ${UNAME_RELEASE}|sed -e 's/-/_/g'`
-	exit ;;
-    ????????:AIX?:[12].1:2)   # AIX 2.2.1 or AIX 2.1.1 is RT/PC AIX.
-	echo romp-ibm-aix     # uname -m gives an 8 hex-code CPU id
-	exit ;;               # Note that: echo "'`uname -s`'" gives 'AIX '
-    i*86:AIX:*:*)
-	echo i386-ibm-aix
-	exit ;;
-    ia64:AIX:*:*)
-	if [ -x /usr/bin/oslevel ] ; then
-		IBM_REV=`/usr/bin/oslevel`
-	else
-		IBM_REV=${UNAME_VERSION}.${UNAME_RELEASE}
-	fi
-	echo ${UNAME_MACHINE}-ibm-aix${IBM_REV}
-	exit ;;
-    *:AIX:2:3)
-	if grep bos325 /usr/include/stdio.h >/dev/null 2>&1; then
-		eval $set_cc_for_build
-		sed 's/^		//' << EOF >$dummy.c
-		#include <sys/systemcfg.h>
-
-		main()
-			{
-			if (!__power_pc())
-				exit(1);
-			puts("powerpc-ibm-aix3.2.5");
-			exit(0);
-			}
-EOF
-		if $CC_FOR_BUILD -o $dummy $dummy.c && SYSTEM_NAME=`$dummy`
-		then
-			echo "$SYSTEM_NAME"
-		else
-			echo rs6000-ibm-aix3.2.5
-		fi
-	elif grep bos324 /usr/include/stdio.h >/dev/null 2>&1; then
-		echo rs6000-ibm-aix3.2.4
-	else
-		echo rs6000-ibm-aix3.2
-	fi
-	exit ;;
-    *:AIX:*:[4567])
-	IBM_CPU_ID=`/usr/sbin/lsdev -C -c processor -S available | sed 1q | awk '{ print $1 }'`
-	if /usr/sbin/lsattr -El ${IBM_CPU_ID} | grep ' POWER' >/dev/null 2>&1; then
-		IBM_ARCH=rs6000
-	else
-		IBM_ARCH=powerpc
-	fi
-	if [ -x /usr/bin/oslevel ] ; then
-		IBM_REV=`/usr/bin/oslevel`
-	else
-		IBM_REV=${UNAME_VERSION}.${UNAME_RELEASE}
-	fi
-	echo ${IBM_ARCH}-ibm-aix${IBM_REV}
-	exit ;;
-    *:AIX:*:*)
-	echo rs6000-ibm-aix
-	exit ;;
-    ibmrt:4.4BSD:*|romp-ibm:BSD:*)
-	echo romp-ibm-bsd4.4
-	exit ;;
-    ibmrt:*BSD:*|romp-ibm:BSD:*)            # covers RT/PC BSD and
-	echo romp-ibm-bsd${UNAME_RELEASE}   # 4.3 with uname added to
-	exit ;;                             # report: romp-ibm BSD 4.3
-    *:BOSX:*:*)
-	echo rs6000-bull-bosx
-	exit ;;
-    DPX/2?00:B.O.S.:*:*)
-	echo m68k-bull-sysv3
-	exit ;;
-    9000/[34]??:4.3bsd:1.*:*)
-	echo m68k-hp-bsd
-	exit ;;
-    hp300:4.4BSD:*:* | 9000/[34]??:4.3bsd:2.*:*)
-	echo m68k-hp-bsd4.4
-	exit ;;
-    9000/[34678]??:HP-UX:*:*)
-	HPUX_REV=`echo ${UNAME_RELEASE}|sed -e 's/[^.]*.[0B]*//'`
-	case "${UNAME_MACHINE}" in
-	    9000/31? )            HP_ARCH=m68000 ;;
-	    9000/[34]?? )         HP_ARCH=m68k ;;
-	    9000/[678][0-9][0-9])
-		if [ -x /usr/bin/getconf ]; then
-		    sc_cpu_version=`/usr/bin/getconf SC_CPU_VERSION 2>/dev/null`
-		    sc_kernel_bits=`/usr/bin/getconf SC_KERNEL_BITS 2>/dev/null`
-		    case "${sc_cpu_version}" in
-		      523) HP_ARCH="hppa1.0" ;; # CPU_PA_RISC1_0
-		      528) HP_ARCH="hppa1.1" ;; # CPU_PA_RISC1_1
-		      532)                      # CPU_PA_RISC2_0
-			case "${sc_kernel_bits}" in
-			  32) HP_ARCH="hppa2.0n" ;;
-			  64) HP_ARCH="hppa2.0w" ;;
-			  '') HP_ARCH="hppa2.0" ;;   # HP-UX 10.20
-			esac ;;
-		    esac
-		fi
-		if [ "${HP_ARCH}" = "" ]; then
-		    eval $set_cc_for_build
-		    sed 's/^		//' << EOF >$dummy.c
-
-		#define _HPUX_SOURCE
-		#include <stdlib.h>
-		#include <unistd.h>
-
-		int main ()
-		{
-		#if defined(_SC_KERNEL_BITS)
-		    long bits = sysconf(_SC_KERNEL_BITS);
-		#endif
-		    long cpu  = sysconf (_SC_CPU_VERSION);
-
-		    switch (cpu)
-			{
-			case CPU_PA_RISC1_0: puts ("hppa1.0"); break;
-			case CPU_PA_RISC1_1: puts ("hppa1.1"); break;
-			case CPU_PA_RISC2_0:
-		#if defined(_SC_KERNEL_BITS)
-			    switch (bits)
-				{
-				case 64: puts ("hppa2.0w"); break;
-				case 32: puts ("hppa2.0n"); break;
-				default: puts ("hppa2.0"); break;
-				} break;
-		#else  /* !defined(_SC_KERNEL_BITS) */
-			    puts ("hppa2.0"); break;
-		#endif
-			default: puts ("hppa1.0"); break;
-			}
-		    exit (0);
-		}
-EOF
-		    (CCOPTS= $CC_FOR_BUILD -o $dummy $dummy.c 2>/dev/null) && HP_ARCH=`$dummy`
-		    test -z "$HP_ARCH" && HP_ARCH=hppa
-		fi ;;
-	esac
-	if [ ${HP_ARCH} = "hppa2.0w" ]
-	then
-	    eval $set_cc_for_build
-
-	    # hppa2.0w-hp-hpux* has a 64-bit kernel and a compiler generating
-	    # 32-bit code.  hppa64-hp-hpux* has the same kernel and a compiler
-	    # generating 64-bit code.  GNU and HP use different nomenclature:
-	    #
-	    # $ CC_FOR_BUILD=cc ./config.guess
-	    # => hppa2.0w-hp-hpux11.23
-	    # $ CC_FOR_BUILD="cc +DA2.0w" ./config.guess
-	    # => hppa64-hp-hpux11.23
-
-	    if echo __LP64__ | (CCOPTS= $CC_FOR_BUILD -E - 2>/dev/null) |
-		grep -q __LP64__
-	    then
-		HP_ARCH="hppa2.0w"
-	    else
-		HP_ARCH="hppa64"
-	    fi
-	fi
-	echo ${HP_ARCH}-hp-hpux${HPUX_REV}
-	exit ;;
-    ia64:HP-UX:*:*)
-	HPUX_REV=`echo ${UNAME_RELEASE}|sed -e 's/[^.]*.[0B]*//'`
-	echo ia64-hp-hpux${HPUX_REV}
-	exit ;;
-    3050*:HI-UX:*:*)
-	eval $set_cc_for_build
-	sed 's/^	//' << EOF >$dummy.c
-	#include <unistd.h>
-	int
-	main ()
-	{
-	  long cpu = sysconf (_SC_CPU_VERSION);
-	  /* The order matters, because CPU_IS_HP_MC68K erroneously returns
-	     true for CPU_PA_RISC1_0.  CPU_IS_PA_RISC returns correct
-	     results, however.  */
-	  if (CPU_IS_PA_RISC (cpu))
-	    {
-	      switch (cpu)
-		{
-		  case CPU_PA_RISC1_0: puts ("hppa1.0-hitachi-hiuxwe2"); break;
-		  case CPU_PA_RISC1_1: puts ("hppa1.1-hitachi-hiuxwe2"); break;
-		  case CPU_PA_RISC2_0: puts ("hppa2.0-hitachi-hiuxwe2"); break;
-		  default: puts ("hppa-hitachi-hiuxwe2"); break;
-		}
-	    }
-	  else if (CPU_IS_HP_MC68K (cpu))
-	    puts ("m68k-hitachi-hiuxwe2");
-	  else puts ("unknown-hitachi-hiuxwe2");
-	  exit (0);
-	}
-EOF
-	$CC_FOR_BUILD -o $dummy $dummy.c && SYSTEM_NAME=`$dummy` &&
-		{ echo "$SYSTEM_NAME"; exit; }
-	echo unknown-hitachi-hiuxwe2
-	exit ;;
-    9000/7??:4.3bsd:*:* | 9000/8?[79]:4.3bsd:*:* )
-	echo hppa1.1-hp-bsd
-	exit ;;
-    9000/8??:4.3bsd:*:*)
-	echo hppa1.0-hp-bsd
-	exit ;;
-    *9??*:MPE/iX:*:* | *3000*:MPE/iX:*:*)
-	echo hppa1.0-hp-mpeix
-	exit ;;
-    hp7??:OSF1:*:* | hp8?[79]:OSF1:*:* )
-	echo hppa1.1-hp-osf
-	exit ;;
-    hp8??:OSF1:*:*)
-	echo hppa1.0-hp-osf
-	exit ;;
-    i*86:OSF1:*:*)
-	if [ -x /usr/sbin/sysversion ] ; then
-	    echo ${UNAME_MACHINE}-unknown-osf1mk
-	else
-	    echo ${UNAME_MACHINE}-unknown-osf1
-	fi
-	exit ;;
-    parisc*:Lites*:*:*)
-	echo hppa1.1-hp-lites
-	exit ;;
-    C1*:ConvexOS:*:* | convex:ConvexOS:C1*:*)
-	echo c1-convex-bsd
-	exit ;;
-    C2*:ConvexOS:*:* | convex:ConvexOS:C2*:*)
-	if getsysinfo -f scalar_acc
-	then echo c32-convex-bsd
-	else echo c2-convex-bsd
-	fi
-	exit ;;
-    C34*:ConvexOS:*:* | convex:ConvexOS:C34*:*)
-	echo c34-convex-bsd
-	exit ;;
-    C38*:ConvexOS:*:* | convex:ConvexOS:C38*:*)
-	echo c38-convex-bsd
-	exit ;;
-    C4*:ConvexOS:*:* | convex:ConvexOS:C4*:*)
-	echo c4-convex-bsd
-	exit ;;
-    CRAY*Y-MP:*:*:*)
-	echo ymp-cray-unicos${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
-	exit ;;
-    CRAY*[A-Z]90:*:*:*)
-	echo ${UNAME_MACHINE}-cray-unicos${UNAME_RELEASE} \
-	| sed -e 's/CRAY.*\([A-Z]90\)/\1/' \
-	      -e y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/ \
-	      -e 's/\.[^.]*$/.X/'
-	exit ;;
-    CRAY*TS:*:*:*)
-	echo t90-cray-unicos${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
-	exit ;;
-    CRAY*T3E:*:*:*)
-	echo alphaev5-cray-unicosmk${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
-	exit ;;
-    CRAY*SV1:*:*:*)
-	echo sv1-cray-unicos${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
-	exit ;;
-    *:UNICOS/mp:*:*)
-	echo craynv-cray-unicosmp${UNAME_RELEASE} | sed -e 's/\.[^.]*$/.X/'
-	exit ;;
-    F30[01]:UNIX_System_V:*:* | F700:UNIX_System_V:*:*)
-	FUJITSU_PROC=`uname -m | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz'`
-	FUJITSU_SYS=`uname -p | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz' | sed -e 's/\///'`
-	FUJITSU_REL=`echo ${UNAME_RELEASE} | sed -e 's/ /_/'`
-	echo "${FUJITSU_PROC}-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
-	exit ;;
-    5000:UNIX_System_V:4.*:*)
-	FUJITSU_SYS=`uname -p | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz' | sed -e 's/\///'`
-	FUJITSU_REL=`echo ${UNAME_RELEASE} | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz' | sed -e 's/ /_/'`
-	echo "sparc-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
-	exit ;;
-    i*86:BSD/386:*:* | i*86:BSD/OS:*:* | *:Ascend\ Embedded/OS:*:*)
-	echo ${UNAME_MACHINE}-pc-bsdi${UNAME_RELEASE}
-	exit ;;
-    sparc*:BSD/OS:*:*)
-	echo sparc-unknown-bsdi${UNAME_RELEASE}
-	exit ;;
-    *:BSD/OS:*:*)
-	echo ${UNAME_MACHINE}-unknown-bsdi${UNAME_RELEASE}
-	exit ;;
-    *:FreeBSD:*:*)
-	UNAME_PROCESSOR=`/usr/bin/uname -p`
-	case ${UNAME_PROCESSOR} in
-	    amd64)
-		echo x86_64-unknown-freebsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'` ;;
-	    *)
-		echo ${UNAME_PROCESSOR}-unknown-freebsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'` ;;
-	esac
-	exit ;;
-    i*:CYGWIN*:*)
-	echo ${UNAME_MACHINE}-pc-cygwin
-	exit ;;
-    *:MINGW*:*)
-	echo ${UNAME_MACHINE}-pc-mingw32
-	exit ;;
-    i*:MSYS*:*)
-	echo ${UNAME_MACHINE}-pc-msys
-	exit ;;
-    i*:windows32*:*)
-	# uname -m includes "-pc" on this system.
-	echo ${UNAME_MACHINE}-mingw32
-	exit ;;
-    i*:PW*:*)
-	echo ${UNAME_MACHINE}-pc-pw32
-	exit ;;
-    *:Interix*:*)
-	case ${UNAME_MACHINE} in
-	    x86)
-		echo i586-pc-interix${UNAME_RELEASE}
-		exit ;;
-	    authenticamd | genuineintel | EM64T)
-		echo x86_64-unknown-interix${UNAME_RELEASE}
-		exit ;;
-	    IA64)
-		echo ia64-unknown-interix${UNAME_RELEASE}
-		exit ;;
-	esac ;;
-    [345]86:Windows_95:* | [345]86:Windows_98:* | [345]86:Windows_NT:*)
-	echo i${UNAME_MACHINE}-pc-mks
-	exit ;;
-    8664:Windows_NT:*)
-	echo x86_64-pc-mks
-	exit ;;
-    i*:Windows_NT*:* | Pentium*:Windows_NT*:*)
-	# How do we know it's Interix rather than the generic POSIX subsystem?
-	# It also conflicts with pre-2.0 versions of AT&T UWIN. Should we
-	# UNAME_MACHINE based on the output of uname instead of i386?
-	echo i586-pc-interix
-	exit ;;
-    i*:UWIN*:*)
-	echo ${UNAME_MACHINE}-pc-uwin
-	exit ;;
-    amd64:CYGWIN*:*:* | x86_64:CYGWIN*:*:*)
-	echo x86_64-unknown-cygwin
-	exit ;;
-    p*:CYGWIN*:*)
-	echo powerpcle-unknown-cygwin
-	exit ;;
-    prep*:SunOS:5.*:*)
-	echo powerpcle-unknown-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
-	exit ;;
-    *:GNU:*:*)
-	# the GNU system
-	echo `echo ${UNAME_MACHINE}|sed -e 's,[-/].*$,,'`-unknown-gnu`echo ${UNAME_RELEASE}|sed -e 's,/.*$,,'`
-	exit ;;
-    *:GNU/*:*:*)
-	# other systems with GNU libc and userland
-	echo ${UNAME_MACHINE}-unknown-`echo ${UNAME_SYSTEM} | sed 's,^[^/]*/,,' | tr '[A-Z]' '[a-z]'``echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`-gnu
-	exit ;;
-    i*86:Minix:*:*)
-	echo ${UNAME_MACHINE}-pc-minix
-	exit ;;
-    alpha:Linux:*:*)
-	case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo` in
-	  EV5)   UNAME_MACHINE=alphaev5 ;;
-	  EV56)  UNAME_MACHINE=alphaev56 ;;
-	  PCA56) UNAME_MACHINE=alphapca56 ;;
-	  PCA57) UNAME_MACHINE=alphapca56 ;;
-	  EV6)   UNAME_MACHINE=alphaev6 ;;
-	  EV67)  UNAME_MACHINE=alphaev67 ;;
-	  EV68*) UNAME_MACHINE=alphaev68 ;;
-	esac
-	objdump --private-headers /bin/sh | grep -q ld.so.1
-	if test "$?" = 0 ; then LIBC="libc1" ; else LIBC="" ; fi
-	echo ${UNAME_MACHINE}-unknown-linux-gnu${LIBC}
-	exit ;;
-    arm*:Linux:*:*)
-	eval $set_cc_for_build
-	if echo __ARM_EABI__ | $CC_FOR_BUILD -E - 2>/dev/null \
-	    | grep -q __ARM_EABI__
-	then
-	    echo ${UNAME_MACHINE}-unknown-linux-gnu
-	else
-	    if echo __ARM_PCS_VFP | $CC_FOR_BUILD -E - 2>/dev/null \
-		| grep -q __ARM_PCS_VFP
-	    then
-		echo ${UNAME_MACHINE}-unknown-linux-gnueabi
-	    else
-		echo ${UNAME_MACHINE}-unknown-linux-gnueabihf
-	    fi
-	fi
-	exit ;;
-    avr32*:Linux:*:*)
-	echo ${UNAME_MACHINE}-unknown-linux-gnu
-	exit ;;
-    cris:Linux:*:*)
-	echo cris-axis-linux-gnu
-	exit ;;
-    crisv32:Linux:*:*)
-	echo crisv32-axis-linux-gnu
-	exit ;;
-    frv:Linux:*:*)
-	echo frv-unknown-linux-gnu
-	exit ;;
-    hexagon:Linux:*:*)
-	echo hexagon-unknown-linux-gnu
-	exit ;;
-    i*86:Linux:*:*)
-	LIBC=gnu
-	eval $set_cc_for_build
-	sed 's/^	//' << EOF >$dummy.c
-	#ifdef __dietlibc__
-	LIBC=dietlibc
-	#endif
-EOF
-	eval `$CC_FOR_BUILD -E $dummy.c 2>/dev/null | grep '^LIBC'`
-	echo "${UNAME_MACHINE}-pc-linux-${LIBC}"
-	exit ;;
-    ia64:Linux:*:*)
-	echo ${UNAME_MACHINE}-unknown-linux-gnu
-	exit ;;
-    m32r*:Linux:*:*)
-	echo ${UNAME_MACHINE}-unknown-linux-gnu
-	exit ;;
-    m68*:Linux:*:*)
-	echo ${UNAME_MACHINE}-unknown-linux-gnu
-	exit ;;
-    mips:Linux:*:* | mips64:Linux:*:*)
-	eval $set_cc_for_build
-	sed 's/^	//' << EOF >$dummy.c
-	#undef CPU
-	#undef ${UNAME_MACHINE}
-	#undef ${UNAME_MACHINE}el
-	#if defined(__MIPSEL__) || defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL)
-	CPU=${UNAME_MACHINE}el
-	#else
-	#if defined(__MIPSEB__) || defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB)
-	CPU=${UNAME_MACHINE}
-	#else
-	CPU=
-	#endif
-	#endif
-EOF
-	eval `$CC_FOR_BUILD -E $dummy.c 2>/dev/null | grep '^CPU'`
-	test x"${CPU}" != x && { echo "${CPU}-unknown-linux-gnu"; exit; }
-	;;
-    or32:Linux:*:*)
-	echo or32-unknown-linux-gnu
-	exit ;;
-    padre:Linux:*:*)
-	echo sparc-unknown-linux-gnu
-	exit ;;
-    parisc64:Linux:*:* | hppa64:Linux:*:*)
-	echo hppa64-unknown-linux-gnu
-	exit ;;
-    parisc:Linux:*:* | hppa:Linux:*:*)
-	# Look for CPU level
-	case `grep '^cpu[^a-z]*:' /proc/cpuinfo 2>/dev/null | cut -d' ' -f2` in
-	  PA7*) echo hppa1.1-unknown-linux-gnu ;;
-	  PA8*) echo hppa2.0-unknown-linux-gnu ;;
-	  *)    echo hppa-unknown-linux-gnu ;;
-	esac
-	exit ;;
-    ppc64:Linux:*:*)
-	echo powerpc64-unknown-linux-gnu
-	exit ;;
-    ppc:Linux:*:*)
-	echo powerpc-unknown-linux-gnu
-	exit ;;
-    s390:Linux:*:* | s390x:Linux:*:*)
-	echo ${UNAME_MACHINE}-ibm-linux
-	exit ;;
-    sh64*:Linux:*:*)
-	echo ${UNAME_MACHINE}-unknown-linux-gnu
-	exit ;;
-    sh*:Linux:*:*)
-	echo ${UNAME_MACHINE}-unknown-linux-gnu
-	exit ;;
-    sparc:Linux:*:* | sparc64:Linux:*:*)
-	echo ${UNAME_MACHINE}-unknown-linux-gnu
-	exit ;;
-    tile*:Linux:*:*)
-	echo ${UNAME_MACHINE}-unknown-linux-gnu
-	exit ;;
-    vax:Linux:*:*)
-	echo ${UNAME_MACHINE}-dec-linux-gnu
-	exit ;;
-    x86_64:Linux:*:*)
-	echo x86_64-unknown-linux-gnu
-	exit ;;
-    xtensa*:Linux:*:*)
-	echo ${UNAME_MACHINE}-unknown-linux-gnu
-	exit ;;
-    i*86:DYNIX/ptx:4*:*)
-	# ptx 4.0 does uname -s correctly, with DYNIX/ptx in there.
-	# earlier versions are messed up and put the nodename in both
-	# sysname and nodename.
-	echo i386-sequent-sysv4
-	exit ;;
-    i*86:UNIX_SV:4.2MP:2.*)
-	# Unixware is an offshoot of SVR4, but it has its own version
-	# number series starting with 2...
-	# I am not positive that other SVR4 systems won't match this,
-	# I just have to hope.  -- rms.
-	# Use sysv4.2uw... so that sysv4* matches it.
-	echo ${UNAME_MACHINE}-pc-sysv4.2uw${UNAME_VERSION}
-	exit ;;
-    i*86:OS/2:*:*)
-	# If we were able to find `uname', then EMX Unix compatibility
-	# is probably installed.
-	echo ${UNAME_MACHINE}-pc-os2-emx
-	exit ;;
-    i*86:XTS-300:*:STOP)
-	echo ${UNAME_MACHINE}-unknown-stop
-	exit ;;
-    i*86:atheos:*:*)
-	echo ${UNAME_MACHINE}-unknown-atheos
-	exit ;;
-    i*86:syllable:*:*)
-	echo ${UNAME_MACHINE}-pc-syllable
-	exit ;;
-    i*86:LynxOS:2.*:* | i*86:LynxOS:3.[01]*:* | i*86:LynxOS:4.[02]*:*)
-	echo i386-unknown-lynxos${UNAME_RELEASE}
-	exit ;;
-    i*86:*DOS:*:*)
-	echo ${UNAME_MACHINE}-pc-msdosdjgpp
-	exit ;;
-    i*86:*:4.*:* | i*86:SYSTEM_V:4.*:*)
-	UNAME_REL=`echo ${UNAME_RELEASE} | sed 's/\/MP$//'`
-	if grep Novell /usr/include/link.h >/dev/null 2>/dev/null; then
-		echo ${UNAME_MACHINE}-univel-sysv${UNAME_REL}
-	else
-		echo ${UNAME_MACHINE}-pc-sysv${UNAME_REL}
-	fi
-	exit ;;
-    i*86:*:5:[678]*)
-	# UnixWare 7.x, OpenUNIX and OpenServer 6.
-	case `/bin/uname -X | grep "^Machine"` in
-	    *486*)	     UNAME_MACHINE=i486 ;;
-	    *Pentium)	     UNAME_MACHINE=i586 ;;
-	    *Pent*|*Celeron) UNAME_MACHINE=i686 ;;
-	esac
-	echo ${UNAME_MACHINE}-unknown-sysv${UNAME_RELEASE}${UNAME_SYSTEM}${UNAME_VERSION}
-	exit ;;
-    i*86:*:3.2:*)
-	if test -f /usr/options/cb.name; then
-		UNAME_REL=`sed -n 's/.*Version //p' </usr/options/cb.name`
-		echo ${UNAME_MACHINE}-pc-isc$UNAME_REL
-	elif /bin/uname -X 2>/dev/null >/dev/null ; then
-		UNAME_REL=`(/bin/uname -X|grep Release|sed -e 's/.*= //')`
-		(/bin/uname -X|grep i80486 >/dev/null) && UNAME_MACHINE=i486
-		(/bin/uname -X|grep '^Machine.*Pentium' >/dev/null) \
-			&& UNAME_MACHINE=i586
-		(/bin/uname -X|grep '^Machine.*Pent *II' >/dev/null) \
-			&& UNAME_MACHINE=i686
-		(/bin/uname -X|grep '^Machine.*Pentium Pro' >/dev/null) \
-			&& UNAME_MACHINE=i686
-		echo ${UNAME_MACHINE}-pc-sco$UNAME_REL
-	else
-		echo ${UNAME_MACHINE}-pc-sysv32
-	fi
-	exit ;;
-    pc:*:*:*)
-	# Left here for compatibility:
-	# uname -m prints for DJGPP always 'pc', but it prints nothing about
-	# the processor, so we play safe by assuming i586.
-	# Note: whatever this is, it MUST be the same as what config.sub
-	# prints for the "djgpp" host, or else GDB configury will decide that
-	# this is a cross-build.
-	echo i586-pc-msdosdjgpp
-	exit ;;
-    Intel:Mach:3*:*)
-	echo i386-pc-mach3
-	exit ;;
-    paragon:*:*:*)
-	echo i860-intel-osf1
-	exit ;;
-    i860:*:4.*:*) # i860-SVR4
-	if grep Stardent /usr/include/sys/uadmin.h >/dev/null 2>&1 ; then
-	  echo i860-stardent-sysv${UNAME_RELEASE} # Stardent Vistra i860-SVR4
-	else # Add other i860-SVR4 vendors below as they are discovered.
-	  echo i860-unknown-sysv${UNAME_RELEASE}  # Unknown i860-SVR4
-	fi
-	exit ;;
-    mini*:CTIX:SYS*5:*)
-	# "miniframe"
-	echo m68010-convergent-sysv
-	exit ;;
-    mc68k:UNIX:SYSTEM5:3.51m)
-	echo m68k-convergent-sysv
-	exit ;;
-    M680?0:D-NIX:5.3:*)
-	echo m68k-diab-dnix
-	exit ;;
-    M68*:*:R3V[5678]*:*)
-	test -r /sysV68 && { echo 'm68k-motorola-sysv'; exit; } ;;
-    3[345]??:*:4.0:3.0 | 3[34]??A:*:4.0:3.0 | 3[34]??,*:*:4.0:3.0 | 3[34]??/*:*:4.0:3.0 | 4400:*:4.0:3.0 | 4850:*:4.0:3.0 | SKA40:*:4.0:3.0 | SDS2:*:4.0:3.0 | SHG2:*:4.0:3.0 | S7501*:*:4.0:3.0)
-	OS_REL=''
-	test -r /etc/.relid \
-	&& OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
-	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
-	  && { echo i486-ncr-sysv4.3${OS_REL}; exit; }
-	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
-	  && { echo i586-ncr-sysv4.3${OS_REL}; exit; } ;;
-    3[34]??:*:4.0:* | 3[34]??,*:*:4.0:*)
-	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
-	  && { echo i486-ncr-sysv4; exit; } ;;
-    NCR*:*:4.2:* | MPRAS*:*:4.2:*)
-	OS_REL='.3'
-	test -r /etc/.relid \
-	    && OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
-	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
-	    && { echo i486-ncr-sysv4.3${OS_REL}; exit; }
-	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
-	    && { echo i586-ncr-sysv4.3${OS_REL}; exit; }
-	/bin/uname -p 2>/dev/null | /bin/grep pteron >/dev/null \
-	    && { echo i586-ncr-sysv4.3${OS_REL}; exit; } ;;
-    m68*:LynxOS:2.*:* | m68*:LynxOS:3.0*:*)
-	echo m68k-unknown-lynxos${UNAME_RELEASE}
-	exit ;;
-    mc68030:UNIX_System_V:4.*:*)
-	echo m68k-atari-sysv4
-	exit ;;
-    TSUNAMI:LynxOS:2.*:*)
-	echo sparc-unknown-lynxos${UNAME_RELEASE}
-	exit ;;
-    rs6000:LynxOS:2.*:*)
-	echo rs6000-unknown-lynxos${UNAME_RELEASE}
-	exit ;;
-    PowerPC:LynxOS:2.*:* | PowerPC:LynxOS:3.[01]*:* | PowerPC:LynxOS:4.[02]*:*)
-	echo powerpc-unknown-lynxos${UNAME_RELEASE}
-	exit ;;
-    SM[BE]S:UNIX_SV:*:*)
-	echo mips-dde-sysv${UNAME_RELEASE}
-	exit ;;
-    RM*:ReliantUNIX-*:*:*)
-	echo mips-sni-sysv4
-	exit ;;
-    RM*:SINIX-*:*:*)
-	echo mips-sni-sysv4
-	exit ;;
-    *:SINIX-*:*:*)
-	if uname -p 2>/dev/null >/dev/null ; then
-		UNAME_MACHINE=`(uname -p) 2>/dev/null`
-		echo ${UNAME_MACHINE}-sni-sysv4
-	else
-		echo ns32k-sni-sysv
-	fi
-	exit ;;
-    PENTIUM:*:4.0*:*)	# Unisys `ClearPath HMP IX 4000' SVR4/MP effort
-			# says <Richard.M.Bartel@ccMail.Census.GOV>
-	echo i586-unisys-sysv4
-	exit ;;
-    *:UNIX_System_V:4*:FTX*)
-	# From Gerald Hewes <hewes@openmarket.com>.
-	# How about differentiating between stratus architectures? -djm
-	echo hppa1.1-stratus-sysv4
-	exit ;;
-    *:*:*:FTX*)
-	# From seanf@swdc.stratus.com.
-	echo i860-stratus-sysv4
-	exit ;;
-    i*86:VOS:*:*)
-	# From Paul.Green@stratus.com.
-	echo ${UNAME_MACHINE}-stratus-vos
-	exit ;;
-    *:VOS:*:*)
-	# From Paul.Green@stratus.com.
-	echo hppa1.1-stratus-vos
-	exit ;;
-    mc68*:A/UX:*:*)
-	echo m68k-apple-aux${UNAME_RELEASE}
-	exit ;;
-    news*:NEWS-OS:6*:*)
-	echo mips-sony-newsos6
-	exit ;;
-    R[34]000:*System_V*:*:* | R4000:UNIX_SYSV:*:* | R*000:UNIX_SV:*:*)
-	if [ -d /usr/nec ]; then
-		echo mips-nec-sysv${UNAME_RELEASE}
-	else
-		echo mips-unknown-sysv${UNAME_RELEASE}
-	fi
-	exit ;;
-    BeBox:BeOS:*:*)	# BeOS running on hardware made by Be, PPC only.
-	echo powerpc-be-beos
-	exit ;;
-    BeMac:BeOS:*:*)	# BeOS running on Mac or Mac clone, PPC only.
-	echo powerpc-apple-beos
-	exit ;;
-    BePC:BeOS:*:*)	# BeOS running on Intel PC compatible.
-	echo i586-pc-beos
-	exit ;;
-    BePC:Haiku:*:*)	# Haiku running on Intel PC compatible.
-	echo i586-pc-haiku
-	exit ;;
-    SX-4:SUPER-UX:*:*)
-	echo sx4-nec-superux${UNAME_RELEASE}
-	exit ;;
-    SX-5:SUPER-UX:*:*)
-	echo sx5-nec-superux${UNAME_RELEASE}
-	exit ;;
-    SX-6:SUPER-UX:*:*)
-	echo sx6-nec-superux${UNAME_RELEASE}
-	exit ;;
-    SX-7:SUPER-UX:*:*)
-	echo sx7-nec-superux${UNAME_RELEASE}
-	exit ;;
-    SX-8:SUPER-UX:*:*)
-	echo sx8-nec-superux${UNAME_RELEASE}
-	exit ;;
-    SX-8R:SUPER-UX:*:*)
-	echo sx8r-nec-superux${UNAME_RELEASE}
-	exit ;;
-    Power*:Rhapsody:*:*)
-	echo powerpc-apple-rhapsody${UNAME_RELEASE}
-	exit ;;
-    *:Rhapsody:*:*)
-	echo ${UNAME_MACHINE}-apple-rhapsody${UNAME_RELEASE}
-	exit ;;
-    *:Darwin:*:*)
-	UNAME_PROCESSOR=`uname -p` || UNAME_PROCESSOR=unknown
-	case $UNAME_PROCESSOR in
-	    i386)
-		eval $set_cc_for_build
-		if [ "$CC_FOR_BUILD" != 'no_compiler_found' ]; then
-		  if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
-		      (CCOPTS= $CC_FOR_BUILD -E - 2>/dev/null) | \
-		      grep IS_64BIT_ARCH >/dev/null
-		  then
-		      UNAME_PROCESSOR="x86_64"
-		  fi
-		fi ;;
-	    unknown) UNAME_PROCESSOR=powerpc ;;
-	esac
-	echo ${UNAME_PROCESSOR}-apple-darwin${UNAME_RELEASE}
-	exit ;;
-    *:procnto*:*:* | *:QNX:[0123456789]*:*)
-	UNAME_PROCESSOR=`uname -p`
-	if test "$UNAME_PROCESSOR" = "x86"; then
-		UNAME_PROCESSOR=i386
-		UNAME_MACHINE=pc
-	fi
-	echo ${UNAME_PROCESSOR}-${UNAME_MACHINE}-nto-qnx${UNAME_RELEASE}
-	exit ;;
-    *:QNX:*:4*)
-	echo i386-pc-qnx
-	exit ;;
-    NEO-?:NONSTOP_KERNEL:*:*)
-	echo neo-tandem-nsk${UNAME_RELEASE}
-	exit ;;
-    NSE-?:NONSTOP_KERNEL:*:*)
-	echo nse-tandem-nsk${UNAME_RELEASE}
-	exit ;;
-    NSR-?:NONSTOP_KERNEL:*:*)
-	echo nsr-tandem-nsk${UNAME_RELEASE}
-	exit ;;
-    *:NonStop-UX:*:*)
-	echo mips-compaq-nonstopux
-	exit ;;
-    BS2000:POSIX*:*:*)
-	echo bs2000-siemens-sysv
-	exit ;;
-    DS/*:UNIX_System_V:*:*)
-	echo ${UNAME_MACHINE}-${UNAME_SYSTEM}-${UNAME_RELEASE}
-	exit ;;
-    *:Plan9:*:*)
-	# "uname -m" is not consistent, so use $cputype instead. 386
-	# is converted to i386 for consistency with other x86
-	# operating systems.
-	if test "$cputype" = "386"; then
-	    UNAME_MACHINE=i386
-	else
-	    UNAME_MACHINE="$cputype"
-	fi
-	echo ${UNAME_MACHINE}-unknown-plan9
-	exit ;;
-    *:TOPS-10:*:*)
-	echo pdp10-unknown-tops10
-	exit ;;
-    *:TENEX:*:*)
-	echo pdp10-unknown-tenex
-	exit ;;
-    KS10:TOPS-20:*:* | KL10:TOPS-20:*:* | TYPE4:TOPS-20:*:*)
-	echo pdp10-dec-tops20
-	exit ;;
-    XKL-1:TOPS-20:*:* | TYPE5:TOPS-20:*:*)
-	echo pdp10-xkl-tops20
-	exit ;;
-    *:TOPS-20:*:*)
-	echo pdp10-unknown-tops20
-	exit ;;
-    *:ITS:*:*)
-	echo pdp10-unknown-its
-	exit ;;
-    SEI:*:*:SEIUX)
-	echo mips-sei-seiux${UNAME_RELEASE}
-	exit ;;
-    *:DragonFly:*:*)
-	echo ${UNAME_MACHINE}-unknown-dragonfly`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`
-	exit ;;
-    *:*VMS:*:*)
-	UNAME_MACHINE=`(uname -p) 2>/dev/null`
-	case "${UNAME_MACHINE}" in
-	    A*) echo alpha-dec-vms ; exit ;;
-	    I*) echo ia64-dec-vms ; exit ;;
-	    V*) echo vax-dec-vms ; exit ;;
-	esac ;;
-    *:XENIX:*:SysV)
-	echo i386-pc-xenix
-	exit ;;
-    i*86:skyos:*:*)
-	echo ${UNAME_MACHINE}-pc-skyos`echo ${UNAME_RELEASE}` | sed -e 's/ .*$//'
-	exit ;;
-    i*86:rdos:*:*)
-	echo ${UNAME_MACHINE}-pc-rdos
-	exit ;;
-    i*86:AROS:*:*)
-	echo ${UNAME_MACHINE}-pc-aros
-	exit ;;
-esac
-
-#echo '(No uname command or uname output not recognized.)' 1>&2
-#echo "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" 1>&2
-
-eval $set_cc_for_build
-cat >$dummy.c <<EOF
-#ifdef _SEQUENT_
-# include <sys/types.h>
-# include <sys/utsname.h>
-#endif
-main ()
-{
-#if defined (sony)
-#if defined (MIPSEB)
-  /* BFD wants "bsd" instead of "newsos".  Perhaps BFD should be changed,
-     I don't know....  */
-  printf ("mips-sony-bsd\n"); exit (0);
-#else
-#include <sys/param.h>
-  printf ("m68k-sony-newsos%s\n",
-#ifdef NEWSOS4
-	"4"
-#else
-	""
-#endif
-	); exit (0);
-#endif
-#endif
-
-#if defined (__arm) && defined (__acorn) && defined (__unix)
-  printf ("arm-acorn-riscix\n"); exit (0);
-#endif
-
-#if defined (hp300) && !defined (hpux)
-  printf ("m68k-hp-bsd\n"); exit (0);
-#endif
-
-#if defined (NeXT)
-#if !defined (__ARCHITECTURE__)
-#define __ARCHITECTURE__ "m68k"
-#endif
-  int version;
-  version=`(hostinfo | sed -n 's/.*NeXT Mach \([0-9]*\).*/\1/p') 2>/dev/null`;
-  if (version < 4)
-    printf ("%s-next-nextstep%d\n", __ARCHITECTURE__, version);
-  else
-    printf ("%s-next-openstep%d\n", __ARCHITECTURE__, version);
-  exit (0);
-#endif
-
-#if defined (MULTIMAX) || defined (n16)
-#if defined (UMAXV)
-  printf ("ns32k-encore-sysv\n"); exit (0);
-#else
-#if defined (CMU)
-  printf ("ns32k-encore-mach\n"); exit (0);
-#else
-  printf ("ns32k-encore-bsd\n"); exit (0);
-#endif
-#endif
-#endif
-
-#if defined (__386BSD__)
-  printf ("i386-pc-bsd\n"); exit (0);
-#endif
-
-#if defined (sequent)
-#if defined (i386)
-  printf ("i386-sequent-dynix\n"); exit (0);
-#endif
-#if defined (ns32000)
-  printf ("ns32k-sequent-dynix\n"); exit (0);
-#endif
-#endif
-
-#if defined (_SEQUENT_)
-    struct utsname un;
-
-    uname(&un);
-
-    if (strncmp(un.version, "V2", 2) == 0) {
-	printf ("i386-sequent-ptx2\n"); exit (0);
-    }
-    if (strncmp(un.version, "V1", 2) == 0) { /* XXX is V1 correct? */
-	printf ("i386-sequent-ptx1\n"); exit (0);
-    }
-    printf ("i386-sequent-ptx\n"); exit (0);
-
-#endif
-
-#if defined (vax)
-# if !defined (ultrix)
-#  include <sys/param.h>
-#  if defined (BSD)
-#   if BSD == 43
-      printf ("vax-dec-bsd4.3\n"); exit (0);
-#   else
-#    if BSD == 199006
-      printf ("vax-dec-bsd4.3reno\n"); exit (0);
-#    else
-      printf ("vax-dec-bsd\n"); exit (0);
-#    endif
-#   endif
-#  else
-    printf ("vax-dec-bsd\n"); exit (0);
-#  endif
-# else
-    printf ("vax-dec-ultrix\n"); exit (0);
-# endif
-#endif
-
-#if defined (alliant) && defined (i860)
-  printf ("i860-alliant-bsd\n"); exit (0);
-#endif
-
-  exit (1);
-}
-EOF
-
-$CC_FOR_BUILD -o $dummy $dummy.c 2>/dev/null && SYSTEM_NAME=`$dummy` &&
-	{ echo "$SYSTEM_NAME"; exit; }
-
-# Apollos put the system type in the environment.
-
-test -d /usr/apollo && { echo ${ISP}-apollo-${SYSTYPE}; exit; }
-
-# Convex versions that predate uname can use getsysinfo(1)
-
-if [ -x /usr/convex/getsysinfo ]
-then
-    case `getsysinfo -f cpu_type` in
-    c1*)
-	echo c1-convex-bsd
-	exit ;;
-    c2*)
-	if getsysinfo -f scalar_acc
-	then echo c32-convex-bsd
-	else echo c2-convex-bsd
-	fi
-	exit ;;
-    c34*)
-	echo c34-convex-bsd
-	exit ;;
-    c38*)
-	echo c38-convex-bsd
-	exit ;;
-    c4*)
-	echo c4-convex-bsd
-	exit ;;
-    esac
-fi
-
-cat >&2 <<EOF
-$0: unable to guess system type
-
-This script, last modified $timestamp, has failed to recognize
-the operating system you are using. It is advised that you
-download the most up to date version of the config scripts from
-
-  http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD
-and
-  http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub;hb=HEAD
-
-If the version you run ($0) is already up to date, please
-send the following data and any information you think might be
-pertinent to <config-patches@gnu.org> in order to provide the needed
-information to handle your system.
-
-config.guess timestamp = $timestamp
-
-uname -m = `(uname -m) 2>/dev/null || echo unknown`
-uname -r = `(uname -r) 2>/dev/null || echo unknown`
-uname -s = `(uname -s) 2>/dev/null || echo unknown`
-uname -v = `(uname -v) 2>/dev/null || echo unknown`
-
-/usr/bin/uname -p = `(/usr/bin/uname -p) 2>/dev/null`
-/bin/uname -X     = `(/bin/uname -X) 2>/dev/null`
-
-hostinfo               = `(hostinfo) 2>/dev/null`
-/bin/universe          = `(/bin/universe) 2>/dev/null`
-/usr/bin/arch -k       = `(/usr/bin/arch -k) 2>/dev/null`
-/bin/arch              = `(/bin/arch) 2>/dev/null`
-/usr/bin/oslevel       = `(/usr/bin/oslevel) 2>/dev/null`
-/usr/convex/getsysinfo = `(/usr/convex/getsysinfo) 2>/dev/null`
-
-UNAME_MACHINE = ${UNAME_MACHINE}
-UNAME_RELEASE = ${UNAME_RELEASE}
-UNAME_SYSTEM  = ${UNAME_SYSTEM}
-UNAME_VERSION = ${UNAME_VERSION}
-EOF
-
-exit 1
-
-# Local variables:
-# eval: (add-hook 'write-file-hooks 'time-stamp)
-# time-stamp-start: "timestamp='"
-# time-stamp-format: "%:y-%02m-%02d"
-# time-stamp-end: "'"
-# End:
diff --git a/extern/libpng/include/config.h.in b/extern/libpng/include/config.h.in
deleted file mode 100644
index d154742738..0000000000
--- a/extern/libpng/include/config.h.in
+++ /dev/null
@@ -1,109 +0,0 @@
-/* config.h.in.  Generated from configure.ac by autoheader.  */
-
-/* Define to 1 if you have the <dlfcn.h> header file. */
-#undef HAVE_DLFCN_H
-
-/* Define to 1 if you have the `feenableexcept' function. */
-#undef HAVE_FEENABLEEXCEPT
-
-/* Define to 1 if you have the <inttypes.h> header file. */
-#undef HAVE_INTTYPES_H
-
-/* Define to 1 if you have the `m' library (-lm). */
-#undef HAVE_LIBM
-
-/* Define to 1 if you have the `z' library (-lz). */
-#undef HAVE_LIBZ
-
-/* Define to 1 if you have the <malloc.h> header file. */
-#undef HAVE_MALLOC_H
-
-/* Define to 1 if you have the <memory.h> header file. */
-#undef HAVE_MEMORY_H
-
-/* Define to 1 if you have the `memset' function. */
-#undef HAVE_MEMSET
-
-/* Define to 1 if you have the `pow' function. */
-#undef HAVE_POW
-
-/* Define to 1 if you have the <stdint.h> header file. */
-#undef HAVE_STDINT_H
-
-/* Define to 1 if you have the <stdlib.h> header file. */
-#undef HAVE_STDLIB_H
-
-/* Define to 1 if you have the <strings.h> header file. */
-#undef HAVE_STRINGS_H
-
-/* Define to 1 if you have the <string.h> header file. */
-#undef HAVE_STRING_H
-
-/* Define to 1 if you have the <sys/stat.h> header file. */
-#undef HAVE_SYS_STAT_H
-
-/* Define to 1 if you have the <sys/types.h> header file. */
-#undef HAVE_SYS_TYPES_H
-
-/* Define to 1 if you have the <unistd.h> header file. */
-#undef HAVE_UNISTD_H
-
-/* Define to the sub-directory in which libtool stores uninstalled libraries.
-   */
-#undef LT_OBJDIR
-
-/* Name of package */
-#undef PACKAGE
-
-/* Define to the address where bug reports for this package should be sent. */
-#undef PACKAGE_BUGREPORT
-
-/* Define to the full name of this package. */
-#undef PACKAGE_NAME
-
-/* Define to the full name and version of this package. */
-#undef PACKAGE_STRING
-
-/* Define to the one symbol short name of this package. */
-#undef PACKAGE_TARNAME
-
-/* Define to the home page for this package. */
-#undef PACKAGE_URL
-
-/* Define to the version of this package. */
-#undef PACKAGE_VERSION
-
-/* Align row buffers */
-#undef PNG_ALIGNED_MEMORY_SUPPORTED
-
-/* Enable ARM NEON optimizations */
-#undef PNG_ARM_NEON
-
-/* Define to 1 if you have the ANSI C header files. */
-#undef STDC_HEADERS
-
-/* Define to 1 if your <sys/time.h> declares `struct tm'. */
-#undef TM_IN_SYS_TIME
-
-/* Version number of package */
-#undef VERSION
-
-/* Define to empty if `const' does not conform to ANSI C. */
-#undef const
-
-/* Define to the equivalent of the C99 'restrict' keyword, or to
-   nothing if this is not supported.  Do not define if restrict is
-   supported directly.  */
-#undef restrict
-/* Work around a bug in Sun C++: it does not support _Restrict or
-   __restrict__, even though the corresponding Sun C compiler ends up with
-   "#define restrict _Restrict" or "#define restrict __restrict__" in the
-   previous line.  Perhaps some future version of Sun C++ will work with
-   restrict; if so, hopefully it defines __RESTRICT like Sun C does.  */
-#if defined __SUNPRO_CC && !defined __RESTRICT
-# define _Restrict
-# define __restrict__
-#endif
-
-/* Define to `unsigned int' if <sys/types.h> does not define. */
-#undef size_t
diff --git a/extern/libpng/include/config.sub b/extern/libpng/include/config.sub
deleted file mode 100644
index e76eaf472a..0000000000
--- a/extern/libpng/include/config.sub
+++ /dev/null
@@ -1,1771 +0,0 @@
-#! /bin/sh
-# Configuration validation subroutine script.
-#   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
-#   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
-#   2011 Free Software Foundation, Inc.
-
-timestamp='2011-11-11'
-
-# This file is (in principle) common to ALL GNU software.
-# The presence of a machine in this file suggests that SOME GNU software
-# can handle that machine.  It does not imply ALL GNU software can.
-#
-# This file is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
-# 02110-1301, USA.
-#
-# As a special exception to the GNU General Public License, if you
-# distribute this file as part of a program that contains a
-# configuration script generated by Autoconf, you may include it under
-# the same distribution terms that you use for the rest of that program.
-
-
-# Please send patches to <config-patches@gnu.org>.  Submit a context
-# diff and a properly formatted GNU ChangeLog entry.
-#
-# Configuration subroutine to validate and canonicalize a configuration type.
-# Supply the specified configuration type as an argument.
-# If it is invalid, we print an error message on stderr and exit with code 1.
-# Otherwise, we print the canonical config type on stdout and succeed.
-
-# You can get the latest version of this script from:
-# http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub;hb=HEAD
-
-# This file is supposed to be the same for all GNU packages
-# and recognize all the CPU types, system types and aliases
-# that are meaningful with *any* GNU software.
-# Each package is responsible for reporting which valid configurations
-# it does not support.  The user should be able to distinguish
-# a failure to support a valid configuration from a meaningless
-# configuration.
-
-# The goal of this file is to map all the various variations of a given
-# machine specification into a single specification in the form:
-#	CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM
-# or in some cases, the newer four-part form:
-#	CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM
-# It is wrong to echo any other type of specification.
-
-me=`echo "$0" | sed -e 's,.*/,,'`
-
-usage="\
-Usage: $0 [OPTION] CPU-MFR-OPSYS
-       $0 [OPTION] ALIAS
-
-Canonicalize a configuration name.
-
-Operation modes:
-  -h, --help         print this help, then exit
-  -t, --time-stamp   print date of last modification, then exit
-  -v, --version      print version number, then exit
-
-Report bugs and patches to <config-patches@gnu.org>."
-
-version="\
-GNU config.sub ($timestamp)
-
-Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free
-Software Foundation, Inc.
-
-This is free software; see the source for copying conditions.  There is NO
-warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
-
-help="
-Try \`$me --help' for more information."
-
-# Parse command line
-while test $# -gt 0 ; do
-  case $1 in
-    --time-stamp | --time* | -t )
-       echo "$timestamp" ; exit ;;
-    --version | -v )
-       echo "$version" ; exit ;;
-    --help | --h* | -h )
-       echo "$usage"; exit ;;
-    -- )     # Stop option processing
-       shift; break ;;
-    - )	# Use stdin as input.
-       break ;;
-    -* )
-       echo "$me: invalid option $1$help"
-       exit 1 ;;
-
-    *local*)
-       # First pass through any local machine types.
-       echo $1
-       exit ;;
-
-    * )
-       break ;;
-  esac
-done
-
-case $# in
- 0) echo "$me: missing argument$help" >&2
-    exit 1;;
- 1) ;;
- *) echo "$me: too many arguments$help" >&2
-    exit 1;;
-esac
-
-# Separate what the user gave into CPU-COMPANY and OS or KERNEL-OS (if any).
-# Here we must recognize all the valid KERNEL-OS combinations.
-maybe_os=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\2/'`
-case $maybe_os in
-  nto-qnx* | linux-gnu* | linux-android* | linux-dietlibc | linux-newlib* | \
-  linux-uclibc* | uclinux-uclibc* | uclinux-gnu* | kfreebsd*-gnu* | \
-  knetbsd*-gnu* | netbsd*-gnu* | \
-  kopensolaris*-gnu* | \
-  storm-chaos* | os2-emx* | rtmk-nova*)
-    os=-$maybe_os
-    basic_machine=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\1/'`
-    ;;
-  *)
-    basic_machine=`echo $1 | sed 's/-[^-]*$//'`
-    if [ $basic_machine != $1 ]
-    then os=`echo $1 | sed 's/.*-/-/'`
-    else os=; fi
-    ;;
-esac
-
-### Let's recognize common machines as not being operating systems so
-### that things like config.sub decstation-3100 work.  We also
-### recognize some manufacturers as not being operating systems, so we
-### can provide default operating systems below.
-case $os in
-	-sun*os*)
-		# Prevent following clause from handling this invalid input.
-		;;
-	-dec* | -mips* | -sequent* | -encore* | -pc532* | -sgi* | -sony* | \
-	-att* | -7300* | -3300* | -delta* | -motorola* | -sun[234]* | \
-	-unicom* | -ibm* | -next | -hp | -isi* | -apollo | -altos* | \
-	-convergent* | -ncr* | -news | -32* | -3600* | -3100* | -hitachi* |\
-	-c[123]* | -convex* | -sun | -crds | -omron* | -dg | -ultra | -tti* | \
-	-harris | -dolphin | -highlevel | -gould | -cbm | -ns | -masscomp | \
-	-apple | -axis | -knuth | -cray | -microblaze)
-		os=
-		basic_machine=$1
-		;;
-	-bluegene*)
-		os=-cnk
-		;;
-	-sim | -cisco | -oki | -wec | -winbond)
-		os=
-		basic_machine=$1
-		;;
-	-scout)
-		;;
-	-wrs)
-		os=-vxworks
-		basic_machine=$1
-		;;
-	-chorusos*)
-		os=-chorusos
-		basic_machine=$1
-		;;
-	-chorusrdb)
-		os=-chorusrdb
-		basic_machine=$1
-		;;
-	-hiux*)
-		os=-hiuxwe2
-		;;
-	-sco6)
-		os=-sco5v6
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-sco5)
-		os=-sco3.2v5
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-sco4)
-		os=-sco3.2v4
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-sco3.2.[4-9]*)
-		os=`echo $os | sed -e 's/sco3.2./sco3.2v/'`
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-sco3.2v[4-9]*)
-		# Don't forget version if it is 3.2v4 or newer.
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-sco5v6*)
-		# Don't forget version if it is 3.2v4 or newer.
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-sco*)
-		os=-sco3.2v2
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-udk*)
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-isc)
-		os=-isc2.2
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-clix*)
-		basic_machine=clipper-intergraph
-		;;
-	-isc*)
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
-		;;
-	-lynx*)
-		os=-lynxos
-		;;
-	-ptx*)
-		basic_machine=`echo $1 | sed -e 's/86-.*/86-sequent/'`
-		;;
-	-windowsnt*)
-		os=`echo $os | sed -e 's/windowsnt/winnt/'`
-		;;
-	-psos*)
-		os=-psos
-		;;
-	-mint | -mint[0-9]*)
-		basic_machine=m68k-atari
-		os=-mint
-		;;
-esac
-
-# Decode aliases for certain CPU-COMPANY combinations.
-case $basic_machine in
-	# Recognize the basic CPU types without company name.
-	# Some are omitted here because they have special meanings below.
-	1750a | 580 \
-	| a29k \
-	| alpha | alphaev[4-8] | alphaev56 | alphaev6[78] | alphapca5[67] \
-	| alpha64 | alpha64ev[4-8] | alpha64ev56 | alpha64ev6[78] | alpha64pca5[67] \
-	| am33_2.0 \
-	| arc | arm | arm[bl]e | arme[lb] | armv[2345] | armv[345][lb] | avr | avr32 \
-        | be32 | be64 \
-	| bfin \
-	| c4x | clipper \
-	| d10v | d30v | dlx | dsp16xx \
-	| epiphany \
-	| fido | fr30 | frv \
-	| h8300 | h8500 | hppa | hppa1.[01] | hppa2.0 | hppa2.0[nw] | hppa64 \
-	| hexagon \
-	| i370 | i860 | i960 | ia64 \
-	| ip2k | iq2000 \
-	| le32 | le64 \
-	| lm32 \
-	| m32c | m32r | m32rle | m68000 | m68k | m88k \
-	| maxq | mb | microblaze | mcore | mep | metag \
-	| mips | mipsbe | mipseb | mipsel | mipsle \
-	| mips16 \
-	| mips64 | mips64el \
-	| mips64octeon | mips64octeonel \
-	| mips64orion | mips64orionel \
-	| mips64r5900 | mips64r5900el \
-	| mips64vr | mips64vrel \
-	| mips64vr4100 | mips64vr4100el \
-	| mips64vr4300 | mips64vr4300el \
-	| mips64vr5000 | mips64vr5000el \
-	| mips64vr5900 | mips64vr5900el \
-	| mipsisa32 | mipsisa32el \
-	| mipsisa32r2 | mipsisa32r2el \
-	| mipsisa64 | mipsisa64el \
-	| mipsisa64r2 | mipsisa64r2el \
-	| mipsisa64sb1 | mipsisa64sb1el \
-	| mipsisa64sr71k | mipsisa64sr71kel \
-	| mipstx39 | mipstx39el \
-	| mn10200 | mn10300 \
-	| moxie \
-	| mt \
-	| msp430 \
-	| nds32 | nds32le | nds32be \
-	| nios | nios2 \
-	| ns16k | ns32k \
-	| open8 \
-	| or32 \
-	| pdp10 | pdp11 | pj | pjl \
-	| powerpc | powerpc64 | powerpc64le | powerpcle \
-	| pyramid \
-	| rl78 | rx \
-	| score \
-	| sh | sh[1234] | sh[24]a | sh[24]aeb | sh[23]e | sh[34]eb | sheb | shbe | shle | sh[1234]le | sh3ele \
-	| sh64 | sh64le \
-	| sparc | sparc64 | sparc64b | sparc64v | sparc86x | sparclet | sparclite \
-	| sparcv8 | sparcv9 | sparcv9b | sparcv9v \
-	| spu \
-	| tahoe | tic4x | tic54x | tic55x | tic6x | tic80 | tron \
-	| ubicom32 \
-	| v850 | v850e | v850e1 | v850e2 | v850es | v850e2v3 \
-	| we32k \
-	| x86 | xc16x | xstormy16 | xtensa \
-	| z8k | z80)
-		basic_machine=$basic_machine-unknown
-		;;
-	c54x)
-		basic_machine=tic54x-unknown
-		;;
-	c55x)
-		basic_machine=tic55x-unknown
-		;;
-	c6x)
-		basic_machine=tic6x-unknown
-		;;
-	m6811 | m68hc11 | m6812 | m68hc12 | picochip)
-		# Motorola 68HC11/12.
-		basic_machine=$basic_machine-unknown
-		os=-none
-		;;
-	m88110 | m680[12346]0 | m683?2 | m68360 | m5200 | v70 | w65 | z8k)
-		;;
-	ms1)
-		basic_machine=mt-unknown
-		;;
-
-	strongarm | thumb | xscale)
-		basic_machine=arm-unknown
-		;;
-
-	xscaleeb)
-		basic_machine=armeb-unknown
-		;;
-
-	xscaleel)
-		basic_machine=armel-unknown
-		;;
-
-	# We use `pc' rather than `unknown'
-	# because (1) that's what they normally are, and
-	# (2) the word "unknown" tends to confuse beginning users.
-	i*86 | x86_64)
-	  basic_machine=$basic_machine-pc
-	  ;;
-	# Object if more than one company name word.
-	*-*-*)
-		echo Invalid configuration \`$1\': machine \`$basic_machine\' not recognized 1>&2
-		exit 1
-		;;
-	# Recognize the basic CPU types with company name.
-	580-* \
-	| a29k-* \
-	| alpha-* | alphaev[4-8]-* | alphaev56-* | alphaev6[78]-* \
-	| alpha64-* | alpha64ev[4-8]-* | alpha64ev56-* | alpha64ev6[78]-* \
-	| alphapca5[67]-* | alpha64pca5[67]-* | arc-* \
-	| arm-*  | armbe-* | armle-* | armeb-* | armv*-* \
-	| avr-* | avr32-* \
-	| be32-* | be64-* \
-	| bfin-* | bs2000-* \
-	| c[123]* | c30-* | [cjt]90-* | c4x-* \
-	| clipper-* | craynv-* | cydra-* \
-	| d10v-* | d30v-* | dlx-* \
-	| elxsi-* \
-	| f30[01]-* | f700-* | fido-* | fr30-* | frv-* | fx80-* \
-	| h8300-* | h8500-* \
-	| hppa-* | hppa1.[01]-* | hppa2.0-* | hppa2.0[nw]-* | hppa64-* \
-	| hexagon-* \
-	| i*86-* | i860-* | i960-* | ia64-* \
-	| ip2k-* | iq2000-* \
-	| le32-* | le64-* \
-	| lm32-* \
-	| m32c-* | m32r-* | m32rle-* \
-	| m68000-* | m680[012346]0-* | m68360-* | m683?2-* | m68k-* \
-	| m88110-* | m88k-* | maxq-* | mcore-* | metag-* | microblaze-* \
-	| mips-* | mipsbe-* | mipseb-* | mipsel-* | mipsle-* \
-	| mips16-* \
-	| mips64-* | mips64el-* \
-	| mips64octeon-* | mips64octeonel-* \
-	| mips64orion-* | mips64orionel-* \
-	| mips64r5900-* | mips64r5900el-* \
-	| mips64vr-* | mips64vrel-* \
-	| mips64vr4100-* | mips64vr4100el-* \
-	| mips64vr4300-* | mips64vr4300el-* \
-	| mips64vr5000-* | mips64vr5000el-* \
-	| mips64vr5900-* | mips64vr5900el-* \
-	| mipsisa32-* | mipsisa32el-* \
-	| mipsisa32r2-* | mipsisa32r2el-* \
-	| mipsisa64-* | mipsisa64el-* \
-	| mipsisa64r2-* | mipsisa64r2el-* \
-	| mipsisa64sb1-* | mipsisa64sb1el-* \
-	| mipsisa64sr71k-* | mipsisa64sr71kel-* \
-	| mipstx39-* | mipstx39el-* \
-	| mmix-* \
-	| mt-* \
-	| msp430-* \
-	| nds32-* | nds32le-* | nds32be-* \
-	| nios-* | nios2-* \
-	| none-* | np1-* | ns16k-* | ns32k-* \
-	| open8-* \
-	| orion-* \
-	| pdp10-* | pdp11-* | pj-* | pjl-* | pn-* | power-* \
-	| powerpc-* | powerpc64-* | powerpc64le-* | powerpcle-* \
-	| pyramid-* \
-	| rl78-* | romp-* | rs6000-* | rx-* \
-	| sh-* | sh[1234]-* | sh[24]a-* | sh[24]aeb-* | sh[23]e-* | sh[34]eb-* | sheb-* | shbe-* \
-	| shle-* | sh[1234]le-* | sh3ele-* | sh64-* | sh64le-* \
-	| sparc-* | sparc64-* | sparc64b-* | sparc64v-* | sparc86x-* | sparclet-* \
-	| sparclite-* \
-	| sparcv8-* | sparcv9-* | sparcv9b-* | sparcv9v-* | sv1-* | sx?-* \
-	| tahoe-* \
-	| tic30-* | tic4x-* | tic54x-* | tic55x-* | tic6x-* | tic80-* \
-	| tile*-* \
-	| tron-* \
-	| ubicom32-* \
-	| v850-* | v850e-* | v850e1-* | v850es-* | v850e2-* | v850e2v3-* \
-	| vax-* \
-	| we32k-* \
-	| x86-* | x86_64-* | xc16x-* | xps100-* \
-	| xstormy16-* | xtensa*-* \
-	| ymp-* \
-	| z8k-* | z80-*)
-		;;
-	# Recognize the basic CPU types without company name, with glob match.
-	xtensa*)
-		basic_machine=$basic_machine-unknown
-		;;
-	# Recognize the various machine names and aliases which stand
-	# for a CPU type and a company and sometimes even an OS.
-	386bsd)
-		basic_machine=i386-unknown
-		os=-bsd
-		;;
-	3b1 | 7300 | 7300-att | att-7300 | pc7300 | safari | unixpc)
-		basic_machine=m68000-att
-		;;
-	3b*)
-		basic_machine=we32k-att
-		;;
-	a29khif)
-		basic_machine=a29k-amd
-		os=-udi
-		;;
-	abacus)
-		basic_machine=abacus-unknown
-		;;
-	adobe68k)
-		basic_machine=m68010-adobe
-		os=-scout
-		;;
-	alliant | fx80)
-		basic_machine=fx80-alliant
-		;;
-	altos | altos3068)
-		basic_machine=m68k-altos
-		;;
-	am29k)
-		basic_machine=a29k-none
-		os=-bsd
-		;;
-	amd64)
-		basic_machine=x86_64-pc
-		;;
-	amd64-*)
-		basic_machine=x86_64-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	amdahl)
-		basic_machine=580-amdahl
-		os=-sysv
-		;;
-	amiga | amiga-*)
-		basic_machine=m68k-unknown
-		;;
-	amigaos | amigados)
-		basic_machine=m68k-unknown
-		os=-amigaos
-		;;
-	amigaunix | amix)
-		basic_machine=m68k-unknown
-		os=-sysv4
-		;;
-	apollo68)
-		basic_machine=m68k-apollo
-		os=-sysv
-		;;
-	apollo68bsd)
-		basic_machine=m68k-apollo
-		os=-bsd
-		;;
-	aros)
-		basic_machine=i386-pc
-		os=-aros
-		;;
-	aux)
-		basic_machine=m68k-apple
-		os=-aux
-		;;
-	balance)
-		basic_machine=ns32k-sequent
-		os=-dynix
-		;;
-	blackfin)
-		basic_machine=bfin-unknown
-		os=-linux
-		;;
-	blackfin-*)
-		basic_machine=bfin-`echo $basic_machine | sed 's/^[^-]*-//'`
-		os=-linux
-		;;
-	bluegene*)
-		basic_machine=powerpc-ibm
-		os=-cnk
-		;;
-	c54x-*)
-		basic_machine=tic54x-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	c55x-*)
-		basic_machine=tic55x-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	c6x-*)
-		basic_machine=tic6x-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	c90)
-		basic_machine=c90-cray
-		os=-unicos
-		;;
-	cegcc)
-		basic_machine=arm-unknown
-		os=-cegcc
-		;;
-	convex-c1)
-		basic_machine=c1-convex
-		os=-bsd
-		;;
-	convex-c2)
-		basic_machine=c2-convex
-		os=-bsd
-		;;
-	convex-c32)
-		basic_machine=c32-convex
-		os=-bsd
-		;;
-	convex-c34)
-		basic_machine=c34-convex
-		os=-bsd
-		;;
-	convex-c38)
-		basic_machine=c38-convex
-		os=-bsd
-		;;
-	cray | j90)
-		basic_machine=j90-cray
-		os=-unicos
-		;;
-	craynv)
-		basic_machine=craynv-cray
-		os=-unicosmp
-		;;
-	cr16 | cr16-*)
-		basic_machine=cr16-unknown
-		os=-elf
-		;;
-	crds | unos)
-		basic_machine=m68k-crds
-		;;
-	crisv32 | crisv32-* | etraxfs*)
-		basic_machine=crisv32-axis
-		;;
-	cris | cris-* | etrax*)
-		basic_machine=cris-axis
-		;;
-	crx)
-		basic_machine=crx-unknown
-		os=-elf
-		;;
-	da30 | da30-*)
-		basic_machine=m68k-da30
-		;;
-	decstation | decstation-3100 | pmax | pmax-* | pmin | dec3100 | decstatn)
-		basic_machine=mips-dec
-		;;
-	decsystem10* | dec10*)
-		basic_machine=pdp10-dec
-		os=-tops10
-		;;
-	decsystem20* | dec20*)
-		basic_machine=pdp10-dec
-		os=-tops20
-		;;
-	delta | 3300 | motorola-3300 | motorola-delta \
-	      | 3300-motorola | delta-motorola)
-		basic_machine=m68k-motorola
-		;;
-	delta88)
-		basic_machine=m88k-motorola
-		os=-sysv3
-		;;
-	dicos)
-		basic_machine=i686-pc
-		os=-dicos
-		;;
-	djgpp)
-		basic_machine=i586-pc
-		os=-msdosdjgpp
-		;;
-	dpx20 | dpx20-*)
-		basic_machine=rs6000-bull
-		os=-bosx
-		;;
-	dpx2* | dpx2*-bull)
-		basic_machine=m68k-bull
-		os=-sysv3
-		;;
-	ebmon29k)
-		basic_machine=a29k-amd
-		os=-ebmon
-		;;
-	elxsi)
-		basic_machine=elxsi-elxsi
-		os=-bsd
-		;;
-	encore | umax | mmax)
-		basic_machine=ns32k-encore
-		;;
-	es1800 | OSE68k | ose68k | ose | OSE)
-		basic_machine=m68k-ericsson
-		os=-ose
-		;;
-	fx2800)
-		basic_machine=i860-alliant
-		;;
-	genix)
-		basic_machine=ns32k-ns
-		;;
-	gmicro)
-		basic_machine=tron-gmicro
-		os=-sysv
-		;;
-	go32)
-		basic_machine=i386-pc
-		os=-go32
-		;;
-	h3050r* | hiux*)
-		basic_machine=hppa1.1-hitachi
-		os=-hiuxwe2
-		;;
-	h8300hms)
-		basic_machine=h8300-hitachi
-		os=-hms
-		;;
-	h8300xray)
-		basic_machine=h8300-hitachi
-		os=-xray
-		;;
-	h8500hms)
-		basic_machine=h8500-hitachi
-		os=-hms
-		;;
-	harris)
-		basic_machine=m88k-harris
-		os=-sysv3
-		;;
-	hp300-*)
-		basic_machine=m68k-hp
-		;;
-	hp300bsd)
-		basic_machine=m68k-hp
-		os=-bsd
-		;;
-	hp300hpux)
-		basic_machine=m68k-hp
-		os=-hpux
-		;;
-	hp3k9[0-9][0-9] | hp9[0-9][0-9])
-		basic_machine=hppa1.0-hp
-		;;
-	hp9k2[0-9][0-9] | hp9k31[0-9])
-		basic_machine=m68000-hp
-		;;
-	hp9k3[2-9][0-9])
-		basic_machine=m68k-hp
-		;;
-	hp9k6[0-9][0-9] | hp6[0-9][0-9])
-		basic_machine=hppa1.0-hp
-		;;
-	hp9k7[0-79][0-9] | hp7[0-79][0-9])
-		basic_machine=hppa1.1-hp
-		;;
-	hp9k78[0-9] | hp78[0-9])
-		# FIXME: really hppa2.0-hp
-		basic_machine=hppa1.1-hp
-		;;
-	hp9k8[67]1 | hp8[67]1 | hp9k80[24] | hp80[24] | hp9k8[78]9 | hp8[78]9 | hp9k893 | hp893)
-		# FIXME: really hppa2.0-hp
-		basic_machine=hppa1.1-hp
-		;;
-	hp9k8[0-9][13679] | hp8[0-9][13679])
-		basic_machine=hppa1.1-hp
-		;;
-	hp9k8[0-9][0-9] | hp8[0-9][0-9])
-		basic_machine=hppa1.0-hp
-		;;
-	hppa-next)
-		os=-nextstep3
-		;;
-	hppaosf)
-		basic_machine=hppa1.1-hp
-		os=-osf
-		;;
-	hppro)
-		basic_machine=hppa1.1-hp
-		os=-proelf
-		;;
-	i370-ibm* | ibm*)
-		basic_machine=i370-ibm
-		;;
-# I'm not sure what "Sysv32" means.  Should this be sysv3.2?
-	i*86v32)
-		basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
-		os=-sysv32
-		;;
-	i*86v4*)
-		basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
-		os=-sysv4
-		;;
-	i*86v)
-		basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
-		os=-sysv
-		;;
-	i*86sol2)
-		basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
-		os=-solaris2
-		;;
-	i386mach)
-		basic_machine=i386-mach
-		os=-mach
-		;;
-	i386-vsta | vsta)
-		basic_machine=i386-unknown
-		os=-vsta
-		;;
-	iris | iris4d)
-		basic_machine=mips-sgi
-		case $os in
-		    -irix*)
-			;;
-		    *)
-			os=-irix4
-			;;
-		esac
-		;;
-	isi68 | isi)
-		basic_machine=m68k-isi
-		os=-sysv
-		;;
-	m68knommu)
-		basic_machine=m68k-unknown
-		os=-linux
-		;;
-	m68knommu-*)
-		basic_machine=m68k-`echo $basic_machine | sed 's/^[^-]*-//'`
-		os=-linux
-		;;
-	m88k-omron*)
-		basic_machine=m88k-omron
-		;;
-	magnum | m3230)
-		basic_machine=mips-mips
-		os=-sysv
-		;;
-	merlin)
-		basic_machine=ns32k-utek
-		os=-sysv
-		;;
-	microblaze)
-		basic_machine=microblaze-xilinx
-		;;
-	mingw32)
-		basic_machine=i386-pc
-		os=-mingw32
-		;;
-	mingw32ce)
-		basic_machine=arm-unknown
-		os=-mingw32ce
-		;;
-	miniframe)
-		basic_machine=m68000-convergent
-		;;
-	*mint | -mint[0-9]* | *MiNT | *MiNT[0-9]*)
-		basic_machine=m68k-atari
-		os=-mint
-		;;
-	mips3*-*)
-		basic_machine=`echo $basic_machine | sed -e 's/mips3/mips64/'`
-		;;
-	mips3*)
-		basic_machine=`echo $basic_machine | sed -e 's/mips3/mips64/'`-unknown
-		;;
-	monitor)
-		basic_machine=m68k-rom68k
-		os=-coff
-		;;
-	morphos)
-		basic_machine=powerpc-unknown
-		os=-morphos
-		;;
-	msdos)
-		basic_machine=i386-pc
-		os=-msdos
-		;;
-	ms1-*)
-		basic_machine=`echo $basic_machine | sed -e 's/ms1-/mt-/'`
-		;;
-	msys)
-		basic_machine=i386-pc
-		os=-msys
-		;;
-	mvs)
-		basic_machine=i370-ibm
-		os=-mvs
-		;;
-	nacl)
-		basic_machine=le32-unknown
-		os=-nacl
-		;;
-	ncr3000)
-		basic_machine=i486-ncr
-		os=-sysv4
-		;;
-	netbsd386)
-		basic_machine=i386-unknown
-		os=-netbsd
-		;;
-	netwinder)
-		basic_machine=armv4l-rebel
-		os=-linux
-		;;
-	news | news700 | news800 | news900)
-		basic_machine=m68k-sony
-		os=-newsos
-		;;
-	news1000)
-		basic_machine=m68030-sony
-		os=-newsos
-		;;
-	news-3600 | risc-news)
-		basic_machine=mips-sony
-		os=-newsos
-		;;
-	necv70)
-		basic_machine=v70-nec
-		os=-sysv
-		;;
-	next | m*-next )
-		basic_machine=m68k-next
-		case $os in
-		    -nextstep* )
-			;;
-		    -ns2*)
-		      os=-nextstep2
-			;;
-		    *)
-		      os=-nextstep3
-			;;
-		esac
-		;;
-	nh3000)
-		basic_machine=m68k-harris
-		os=-cxux
-		;;
-	nh[45]000)
-		basic_machine=m88k-harris
-		os=-cxux
-		;;
-	nindy960)
-		basic_machine=i960-intel
-		os=-nindy
-		;;
-	mon960)
-		basic_machine=i960-intel
-		os=-mon960
-		;;
-	nonstopux)
-		basic_machine=mips-compaq
-		os=-nonstopux
-		;;
-	np1)
-		basic_machine=np1-gould
-		;;
-	neo-tandem)
-		basic_machine=neo-tandem
-		;;
-	nse-tandem)
-		basic_machine=nse-tandem
-		;;
-	nsr-tandem)
-		basic_machine=nsr-tandem
-		;;
-	op50n-* | op60c-*)
-		basic_machine=hppa1.1-oki
-		os=-proelf
-		;;
-	openrisc | openrisc-*)
-		basic_machine=or32-unknown
-		;;
-	os400)
-		basic_machine=powerpc-ibm
-		os=-os400
-		;;
-	OSE68000 | ose68000)
-		basic_machine=m68000-ericsson
-		os=-ose
-		;;
-	os68k)
-		basic_machine=m68k-none
-		os=-os68k
-		;;
-	pa-hitachi)
-		basic_machine=hppa1.1-hitachi
-		os=-hiuxwe2
-		;;
-	paragon)
-		basic_machine=i860-intel
-		os=-osf
-		;;
-	parisc)
-		basic_machine=hppa-unknown
-		os=-linux
-		;;
-	parisc-*)
-		basic_machine=hppa-`echo $basic_machine | sed 's/^[^-]*-//'`
-		os=-linux
-		;;
-	pbd)
-		basic_machine=sparc-tti
-		;;
-	pbb)
-		basic_machine=m68k-tti
-		;;
-	pc532 | pc532-*)
-		basic_machine=ns32k-pc532
-		;;
-	pc98)
-		basic_machine=i386-pc
-		;;
-	pc98-*)
-		basic_machine=i386-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	pentium | p5 | k5 | k6 | nexgen | viac3)
-		basic_machine=i586-pc
-		;;
-	pentiumpro | p6 | 6x86 | athlon | athlon_*)
-		basic_machine=i686-pc
-		;;
-	pentiumii | pentium2 | pentiumiii | pentium3)
-		basic_machine=i686-pc
-		;;
-	pentium4)
-		basic_machine=i786-pc
-		;;
-	pentium-* | p5-* | k5-* | k6-* | nexgen-* | viac3-*)
-		basic_machine=i586-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	pentiumpro-* | p6-* | 6x86-* | athlon-*)
-		basic_machine=i686-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	pentiumii-* | pentium2-* | pentiumiii-* | pentium3-*)
-		basic_machine=i686-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	pentium4-*)
-		basic_machine=i786-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	pn)
-		basic_machine=pn-gould
-		;;
-	power)	basic_machine=power-ibm
-		;;
-	ppc | ppcbe)	basic_machine=powerpc-unknown
-		;;
-	ppc-* | ppcbe-*)
-		basic_machine=powerpc-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	ppcle | powerpclittle | ppc-le | powerpc-little)
-		basic_machine=powerpcle-unknown
-		;;
-	ppcle-* | powerpclittle-*)
-		basic_machine=powerpcle-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	ppc64)	basic_machine=powerpc64-unknown
-		;;
-	ppc64-*) basic_machine=powerpc64-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	ppc64le | powerpc64little | ppc64-le | powerpc64-little)
-		basic_machine=powerpc64le-unknown
-		;;
-	ppc64le-* | powerpc64little-*)
-		basic_machine=powerpc64le-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	ps2)
-		basic_machine=i386-ibm
-		;;
-	pw32)
-		basic_machine=i586-unknown
-		os=-pw32
-		;;
-	rdos)
-		basic_machine=i386-pc
-		os=-rdos
-		;;
-	rom68k)
-		basic_machine=m68k-rom68k
-		os=-coff
-		;;
-	rm[46]00)
-		basic_machine=mips-siemens
-		;;
-	rtpc | rtpc-*)
-		basic_machine=romp-ibm
-		;;
-	s390 | s390-*)
-		basic_machine=s390-ibm
-		;;
-	s390x | s390x-*)
-		basic_machine=s390x-ibm
-		;;
-	sa29200)
-		basic_machine=a29k-amd
-		os=-udi
-		;;
-	sb1)
-		basic_machine=mipsisa64sb1-unknown
-		;;
-	sb1el)
-		basic_machine=mipsisa64sb1el-unknown
-		;;
-	sde)
-		basic_machine=mipsisa32-sde
-		os=-elf
-		;;
-	sei)
-		basic_machine=mips-sei
-		os=-seiux
-		;;
-	sequent)
-		basic_machine=i386-sequent
-		;;
-	sh)
-		basic_machine=sh-hitachi
-		os=-hms
-		;;
-	sh5el)
-		basic_machine=sh5le-unknown
-		;;
-	sh64)
-		basic_machine=sh64-unknown
-		;;
-	sparclite-wrs | simso-wrs)
-		basic_machine=sparclite-wrs
-		os=-vxworks
-		;;
-	sps7)
-		basic_machine=m68k-bull
-		os=-sysv2
-		;;
-	spur)
-		basic_machine=spur-unknown
-		;;
-	st2000)
-		basic_machine=m68k-tandem
-		;;
-	stratus)
-		basic_machine=i860-stratus
-		os=-sysv4
-		;;
-	strongarm-* | thumb-*)
-		basic_machine=arm-`echo $basic_machine | sed 's/^[^-]*-//'`
-		;;
-	sun2)
-		basic_machine=m68000-sun
-		;;
-	sun2os3)
-		basic_machine=m68000-sun
-		os=-sunos3
-		;;
-	sun2os4)
-		basic_machine=m68000-sun
-		os=-sunos4
-		;;
-	sun3os3)
-		basic_machine=m68k-sun
-		os=-sunos3
-		;;
-	sun3os4)
-		basic_machine=m68k-sun
-		os=-sunos4
-		;;
-	sun4os3)
-		basic_machine=sparc-sun
-		os=-sunos3
-		;;
-	sun4os4)
-		basic_machine=sparc-sun
-		os=-sunos4
-		;;
-	sun4sol2)
-		basic_machine=sparc-sun
-		os=-solaris2
-		;;
-	sun3 | sun3-*)
-		basic_machine=m68k-sun
-		;;
-	sun4)
-		basic_machine=sparc-sun
-		;;
-	sun386 | sun386i | roadrunner)
-		basic_machine=i386-sun
-		;;
-	sv1)
-		basic_machine=sv1-cray
-		os=-unicos
-		;;
-	symmetry)
-		basic_machine=i386-sequent
-		os=-dynix
-		;;
-	t3e)
-		basic_machine=alphaev5-cray
-		os=-unicos
-		;;
-	t90)
-		basic_machine=t90-cray
-		os=-unicos
-		;;
-	tile*)
-		basic_machine=$basic_machine-unknown
-		os=-linux-gnu
-		;;
-	tx39)
-		basic_machine=mipstx39-unknown
-		;;
-	tx39el)
-		basic_machine=mipstx39el-unknown
-		;;
-	toad1)
-		basic_machine=pdp10-xkl
-		os=-tops20
-		;;
-	tower | tower-32)
-		basic_machine=m68k-ncr
-		;;
-	tpf)
-		basic_machine=s390x-ibm
-		os=-tpf
-		;;
-	udi29k)
-		basic_machine=a29k-amd
-		os=-udi
-		;;
-	ultra3)
-		basic_machine=a29k-nyu
-		os=-sym1
-		;;
-	v810 | necv810)
-		basic_machine=v810-nec
-		os=-none
-		;;
-	vaxv)
-		basic_machine=vax-dec
-		os=-sysv
-		;;
-	vms)
-		basic_machine=vax-dec
-		os=-vms
-		;;
-	vpp*|vx|vx-*)
-		basic_machine=f301-fujitsu
-		;;
-	vxworks960)
-		basic_machine=i960-wrs
-		os=-vxworks
-		;;
-	vxworks68)
-		basic_machine=m68k-wrs
-		os=-vxworks
-		;;
-	vxworks29k)
-		basic_machine=a29k-wrs
-		os=-vxworks
-		;;
-	w65*)
-		basic_machine=w65-wdc
-		os=-none
-		;;
-	w89k-*)
-		basic_machine=hppa1.1-winbond
-		os=-proelf
-		;;
-	xbox)
-		basic_machine=i686-pc
-		os=-mingw32
-		;;
-	xps | xps100)
-		basic_machine=xps100-honeywell
-		;;
-	xscale-* | xscalee[bl]-*)
-		basic_machine=`echo $basic_machine | sed 's/^xscale/arm/'`
-		;;
-	ymp)
-		basic_machine=ymp-cray
-		os=-unicos
-		;;
-	z8k-*-coff)
-		basic_machine=z8k-unknown
-		os=-sim
-		;;
-	z80-*-coff)
-		basic_machine=z80-unknown
-		os=-sim
-		;;
-	none)
-		basic_machine=none-none
-		os=-none
-		;;
-
-# Here we handle the default manufacturer of certain CPU types.  It is in
-# some cases the only manufacturer, in others, it is the most popular.
-	w89k)
-		basic_machine=hppa1.1-winbond
-		;;
-	op50n)
-		basic_machine=hppa1.1-oki
-		;;
-	op60c)
-		basic_machine=hppa1.1-oki
-		;;
-	romp)
-		basic_machine=romp-ibm
-		;;
-	mmix)
-		basic_machine=mmix-knuth
-		;;
-	rs6000)
-		basic_machine=rs6000-ibm
-		;;
-	vax)
-		basic_machine=vax-dec
-		;;
-	pdp10)
-		# there are many clones, so DEC is not a safe bet
-		basic_machine=pdp10-unknown
-		;;
-	pdp11)
-		basic_machine=pdp11-dec
-		;;
-	we32k)
-		basic_machine=we32k-att
-		;;
-	sh[1234] | sh[24]a | sh[24]aeb | sh[34]eb | sh[1234]le | sh[23]ele)
-		basic_machine=sh-unknown
-		;;
-	sparc | sparcv8 | sparcv9 | sparcv9b | sparcv9v)
-		basic_machine=sparc-sun
-		;;
-	cydra)
-		basic_machine=cydra-cydrome
-		;;
-	orion)
-		basic_machine=orion-highlevel
-		;;
-	orion105)
-		basic_machine=clipper-highlevel
-		;;
-	mac | mpw | mac-mpw)
-		basic_machine=m68k-apple
-		;;
-	pmac | pmac-mpw)
-		basic_machine=powerpc-apple
-		;;
-	*-unknown)
-		# Make sure to match an already-canonicalized machine name.
-		;;
-	*)
-		echo Invalid configuration \`$1\': machine \`$basic_machine\' not recognized 1>&2
-		exit 1
-		;;
-esac
-
-# Here we canonicalize certain aliases for manufacturers.
-case $basic_machine in
-	*-digital*)
-		basic_machine=`echo $basic_machine | sed 's/digital.*/dec/'`
-		;;
-	*-commodore*)
-		basic_machine=`echo $basic_machine | sed 's/commodore.*/cbm/'`
-		;;
-	*)
-		;;
-esac
-
-# Decode manufacturer-specific aliases for certain operating systems.
-
-if [ x"$os" != x"" ]
-then
-case $os in
-	# First match some system type aliases
-	# that might get confused with valid system types.
-	# -solaris* is a basic system type, with this one exception.
-	-auroraux)
-		os=-auroraux
-		;;
-	-solaris1 | -solaris1.*)
-		os=`echo $os | sed -e 's|solaris1|sunos4|'`
-		;;
-	-solaris)
-		os=-solaris2
-		;;
-	-svr4*)
-		os=-sysv4
-		;;
-	-unixware*)
-		os=-sysv4.2uw
-		;;
-	-gnu/linux*)
-		os=`echo $os | sed -e 's|gnu/linux|linux-gnu|'`
-		;;
-	# First accept the basic system types.
-	# The portable systems comes first.
-	# Each alternative MUST END IN A *, to match a version number.
-	# -sysv* is not here because it comes later, after sysvr4.
-	-gnu* | -bsd* | -mach* | -minix* | -genix* | -ultrix* | -irix* \
-	      | -*vms* | -sco* | -esix* | -isc* | -aix* | -cnk* | -sunos | -sunos[34]*\
-	      | -hpux* | -unos* | -osf* | -luna* | -dgux* | -auroraux* | -solaris* \
-	      | -sym* | -kopensolaris* \
-	      | -amigaos* | -amigados* | -msdos* | -newsos* | -unicos* | -aof* \
-	      | -aos* | -aros* \
-	      | -nindy* | -vxsim* | -vxworks* | -ebmon* | -hms* | -mvs* \
-	      | -clix* | -riscos* | -uniplus* | -iris* | -rtu* | -xenix* \
-	      | -hiux* | -386bsd* | -knetbsd* | -mirbsd* | -netbsd* \
-	      | -openbsd* | -solidbsd* \
-	      | -ekkobsd* | -kfreebsd* | -freebsd* | -riscix* | -lynxos* \
-	      | -bosx* | -nextstep* | -cxux* | -aout* | -elf* | -oabi* \
-	      | -ptx* | -coff* | -ecoff* | -winnt* | -domain* | -vsta* \
-	      | -udi* | -eabi* | -lites* | -ieee* | -go32* | -aux* \
-	      | -chorusos* | -chorusrdb* | -cegcc* \
-	      | -cygwin* | -msys* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
-	      | -mingw32* | -linux-gnu* | -linux-android* \
-	      | -linux-newlib* | -linux-uclibc* \
-	      | -uxpv* | -beos* | -mpeix* | -udk* \
-	      | -interix* | -uwin* | -mks* | -rhapsody* | -darwin* | -opened* \
-	      | -openstep* | -oskit* | -conix* | -pw32* | -nonstopux* \
-	      | -storm-chaos* | -tops10* | -tenex* | -tops20* | -its* \
-	      | -os2* | -vos* | -palmos* | -uclinux* | -nucleus* \
-	      | -morphos* | -superux* | -rtmk* | -rtmk-nova* | -windiss* \
-	      | -powermax* | -dnix* | -nx6 | -nx7 | -sei* | -dragonfly* \
-	      | -skyos* | -haiku* | -rdos* | -toppers* | -drops* | -es*)
-	# Remember, each alternative MUST END IN *, to match a version number.
-		;;
-	-qnx*)
-		case $basic_machine in
-		    x86-* | i*86-*)
-			;;
-		    *)
-			os=-nto$os
-			;;
-		esac
-		;;
-	-nto-qnx*)
-		;;
-	-nto*)
-		os=`echo $os | sed -e 's|nto|nto-qnx|'`
-		;;
-	-sim | -es1800* | -hms* | -xray | -os68k* | -none* | -v88r* \
-	      | -windows* | -osx | -abug | -netware* | -os9* | -beos* | -haiku* \
-	      | -macos* | -mpw* | -magic* | -mmixware* | -mon960* | -lnews*)
-		;;
-	-mac*)
-		os=`echo $os | sed -e 's|mac|macos|'`
-		;;
-	-linux-dietlibc)
-		os=-linux-dietlibc
-		;;
-	-linux*)
-		os=`echo $os | sed -e 's|linux|linux-gnu|'`
-		;;
-	-sunos5*)
-		os=`echo $os | sed -e 's|sunos5|solaris2|'`
-		;;
-	-sunos6*)
-		os=`echo $os | sed -e 's|sunos6|solaris3|'`
-		;;
-	-opened*)
-		os=-openedition
-		;;
-	-os400*)
-		os=-os400
-		;;
-	-wince*)
-		os=-wince
-		;;
-	-osfrose*)
-		os=-osfrose
-		;;
-	-osf*)
-		os=-osf
-		;;
-	-utek*)
-		os=-bsd
-		;;
-	-dynix*)
-		os=-bsd
-		;;
-	-acis*)
-		os=-aos
-		;;
-	-atheos*)
-		os=-atheos
-		;;
-	-syllable*)
-		os=-syllable
-		;;
-	-386bsd)
-		os=-bsd
-		;;
-	-ctix* | -uts*)
-		os=-sysv
-		;;
-	-nova*)
-		os=-rtmk-nova
-		;;
-	-ns2 )
-		os=-nextstep2
-		;;
-	-nsk*)
-		os=-nsk
-		;;
-	# Preserve the version number of sinix5.
-	-sinix5.*)
-		os=`echo $os | sed -e 's|sinix|sysv|'`
-		;;
-	-sinix*)
-		os=-sysv4
-		;;
-	-tpf*)
-		os=-tpf
-		;;
-	-triton*)
-		os=-sysv3
-		;;
-	-oss*)
-		os=-sysv3
-		;;
-	-svr4)
-		os=-sysv4
-		;;
-	-svr3)
-		os=-sysv3
-		;;
-	-sysvr4)
-		os=-sysv4
-		;;
-	# This must come after -sysvr4.
-	-sysv*)
-		;;
-	-ose*)
-		os=-ose
-		;;
-	-es1800*)
-		os=-ose
-		;;
-	-xenix)
-		os=-xenix
-		;;
-	-*mint | -mint[0-9]* | -*MiNT | -MiNT[0-9]*)
-		os=-mint
-		;;
-	-aros*)
-		os=-aros
-		;;
-	-kaos*)
-		os=-kaos
-		;;
-	-zvmoe)
-		os=-zvmoe
-		;;
-	-dicos*)
-		os=-dicos
-		;;
-	-nacl*)
-		;;
-	-none)
-		;;
-	*)
-		# Get rid of the `-' at the beginning of $os.
-		os=`echo $os | sed 's/[^-]*-//'`
-		echo Invalid configuration \`$1\': system \`$os\' not recognized 1>&2
-		exit 1
-		;;
-esac
-else
-
-# Here we handle the default operating systems that come with various machines.
-# The value should be what the vendor currently ships out the door with their
-# machine or put another way, the most popular os provided with the machine.
-
-# Note that if you're going to try to match "-MANUFACTURER" here (say,
-# "-sun"), then you have to tell the case statement up towards the top
-# that MANUFACTURER isn't an operating system.  Otherwise, code above
-# will signal an error saying that MANUFACTURER isn't an operating
-# system, and we'll never get to this point.
-
-case $basic_machine in
-	score-*)
-		os=-elf
-		;;
-	spu-*)
-		os=-elf
-		;;
-	*-acorn)
-		os=-riscix1.2
-		;;
-	arm*-rebel)
-		os=-linux
-		;;
-	arm*-semi)
-		os=-aout
-		;;
-	c4x-* | tic4x-*)
-		os=-coff
-		;;
-	tic54x-*)
-		os=-coff
-		;;
-	tic55x-*)
-		os=-coff
-		;;
-	tic6x-*)
-		os=-coff
-		;;
-	# This must come before the *-dec entry.
-	pdp10-*)
-		os=-tops20
-		;;
-	pdp11-*)
-		os=-none
-		;;
-	*-dec | vax-*)
-		os=-ultrix4.2
-		;;
-	m68*-apollo)
-		os=-domain
-		;;
-	i386-sun)
-		os=-sunos4.0.2
-		;;
-	m68000-sun)
-		os=-sunos3
-		# This also exists in the configure program, but was not the
-		# default.
-		# os=-sunos4
-		;;
-	m68*-cisco)
-		os=-aout
-		;;
-	mep-*)
-		os=-elf
-		;;
-	mips*-cisco)
-		os=-elf
-		;;
-	mips*-*)
-		os=-elf
-		;;
-	or32-*)
-		os=-coff
-		;;
-	*-tti)	# must be before sparc entry or we get the wrong os.
-		os=-sysv3
-		;;
-	sparc-* | *-sun)
-		os=-sunos4.1.1
-		;;
-	*-be)
-		os=-beos
-		;;
-	*-haiku)
-		os=-haiku
-		;;
-	*-ibm)
-		os=-aix
-		;;
-	*-knuth)
-		os=-mmixware
-		;;
-	*-wec)
-		os=-proelf
-		;;
-	*-winbond)
-		os=-proelf
-		;;
-	*-oki)
-		os=-proelf
-		;;
-	*-hp)
-		os=-hpux
-		;;
-	*-hitachi)
-		os=-hiux
-		;;
-	i860-* | *-att | *-ncr | *-altos | *-motorola | *-convergent)
-		os=-sysv
-		;;
-	*-cbm)
-		os=-amigaos
-		;;
-	*-dg)
-		os=-dgux
-		;;
-	*-dolphin)
-		os=-sysv3
-		;;
-	m68k-ccur)
-		os=-rtu
-		;;
-	m88k-omron*)
-		os=-luna
-		;;
-	*-next )
-		os=-nextstep
-		;;
-	*-sequent)
-		os=-ptx
-		;;
-	*-crds)
-		os=-unos
-		;;
-	*-ns)
-		os=-genix
-		;;
-	i370-*)
-		os=-mvs
-		;;
-	*-next)
-		os=-nextstep3
-		;;
-	*-gould)
-		os=-sysv
-		;;
-	*-highlevel)
-		os=-bsd
-		;;
-	*-encore)
-		os=-bsd
-		;;
-	*-sgi)
-		os=-irix
-		;;
-	*-siemens)
-		os=-sysv4
-		;;
-	*-masscomp)
-		os=-rtu
-		;;
-	f30[01]-fujitsu | f700-fujitsu)
-		os=-uxpv
-		;;
-	*-rom68k)
-		os=-coff
-		;;
-	*-*bug)
-		os=-coff
-		;;
-	*-apple)
-		os=-macos
-		;;
-	*-atari*)
-		os=-mint
-		;;
-	*)
-		os=-none
-		;;
-esac
-fi
-
-# Here we handle the case where we know the os, and the CPU type, but not the
-# manufacturer.  We pick the logical manufacturer.
-vendor=unknown
-case $basic_machine in
-	*-unknown)
-		case $os in
-			-riscix*)
-				vendor=acorn
-				;;
-			-sunos*)
-				vendor=sun
-				;;
-			-cnk*|-aix*)
-				vendor=ibm
-				;;
-			-beos*)
-				vendor=be
-				;;
-			-hpux*)
-				vendor=hp
-				;;
-			-mpeix*)
-				vendor=hp
-				;;
-			-hiux*)
-				vendor=hitachi
-				;;
-			-unos*)
-				vendor=crds
-				;;
-			-dgux*)
-				vendor=dg
-				;;
-			-luna*)
-				vendor=omron
-				;;
-			-genix*)
-				vendor=ns
-				;;
-			-mvs* | -opened*)
-				vendor=ibm
-				;;
-			-os400*)
-				vendor=ibm
-				;;
-			-ptx*)
-				vendor=sequent
-				;;
-			-tpf*)
-				vendor=ibm
-				;;
-			-vxsim* | -vxworks* | -windiss*)
-				vendor=wrs
-				;;
-			-aux*)
-				vendor=apple
-				;;
-			-hms*)
-				vendor=hitachi
-				;;
-			-mpw* | -macos*)
-				vendor=apple
-				;;
-			-*mint | -mint[0-9]* | -*MiNT | -MiNT[0-9]*)
-				vendor=atari
-				;;
-			-vos*)
-				vendor=stratus
-				;;
-		esac
-		basic_machine=`echo $basic_machine | sed "s/unknown/$vendor/"`
-		;;
-esac
-
-echo $basic_machine$os
-exit
-
-# Local variables:
-# eval: (add-hook 'write-file-hooks 'time-stamp)
-# time-stamp-start: "timestamp='"
-# time-stamp-format: "%:y-%02m-%02d"
-# time-stamp-end: "'"
-# End:
diff --git a/extern/libpng/include/configure.ac b/extern/libpng/include/configure.ac
deleted file mode 100644
index 023aba43b3..0000000000
--- a/extern/libpng/include/configure.ac
+++ /dev/null
@@ -1,204 +0,0 @@
-# configure.ac
-
-dnl Process this file with autoconf to produce a configure script.
-dnl
-dnl Minor upgrades (compatible ABI): increment the package version
-dnl (third field in two places below) and set the PNGLIB_RELEASE
-dnl variable.
-dnl
-dnl Major upgrades (incompatible ABI): increment the package major
-dnl version (second field, or first if desired), set the minor
-dnl to 0, set PNGLIB_MAJOR below *and* follow the instructions in
-dnl Makefile.am to upgrade the package name.
-
-dnl This is here to prevent earlier autoconf from being used, it
-dnl should not be necessary to regenerate configure if the time
-dnl stamps are correct
-AC_PREREQ(2.59)
-
-dnl Version number stuff here:
-
-AC_INIT([libpng], [1.5.10], [png-mng-implement@lists.sourceforge.net])
-AM_INIT_AUTOMAKE
-dnl stop configure from automagically running automake
-AM_MAINTAINER_MODE
-
-PNGLIB_VERSION=1.5.10
-PNGLIB_MAJOR=1
-PNGLIB_MINOR=5
-PNGLIB_RELEASE=10
-
-dnl End of version number stuff
-
-AC_CONFIG_SRCDIR([pngget.c])
-AM_CONFIG_HEADER(config.h)
-
-# Checks for programs.
-AC_LANG([C])
-AC_PROG_CC
-AM_PROG_AS
-AC_PROG_LD
-AC_PROG_CPP
-AC_CHECK_TOOL(SED, sed, :)
-AC_CHECK_TOOL(AWK, awk, :)
-AC_PROG_INSTALL
-AC_PROG_LN_S
-AC_PROG_MAKE_SET
-LT_INIT([win32-dll])
-
-# On Solaris 10 and 12 CPP gets set to cc -E, however this still
-# does some input parsing.  We need strict ANSI-C style tokenization,
-# check this:
-AC_REQUIRE_CPP
-AC_MSG_CHECKING([for a C preprocessor that does not parse its input])
-AC_TRY_CPP([1.5.0 16BIT],
-   [DFNCPP="$CPP"],
-   [DFNCPP=""
-   sav_CPP="$CPP"
-   for CPP in "${CC-cc} -E" "${CC-cc} -E -traditional-cpp" "/lib/cpp" "cpp"; do
-      AC_TRY_CPP([1.5.0 16BIT],
-         [DFNCPP="$CPP"]
-         [break],,)
-   done
-   CPP="$sav_CPP"])
-if test -n "$DFNCPP"; then
-   AC_MSG_RESULT([$DFNCPP])
-   AC_SUBST(DFNCPP)
-else
-   AC_MSG_FAILURE([not found], 1)
-fi
-
-# Checks for header files.
-AC_HEADER_STDC
-AC_CHECK_HEADERS([malloc.h stdlib.h string.h strings.h])
-
-# Checks for typedefs, structures, and compiler characteristics.
-AC_C_CONST
-AC_TYPE_SIZE_T
-AC_STRUCT_TM
-AC_C_RESTRICT
-
-# Checks for library functions.
-AC_FUNC_STRTOD
-AC_CHECK_FUNCS([memset], , AC_ERROR([memset not found in libc]))
-AC_CHECK_FUNCS([pow], , AC_CHECK_LIB(m, pow, , AC_ERROR([cannot find pow])) )
-AC_ARG_WITH(zlib-prefix,
-   AC_HELP_STRING([--with-zlib-prefix],
-                  [prefix that may have been used in installed zlib]),
-                  [ZPREFIX=${withval}],
-                  [ZPREFIX='z_'])
-AC_CHECK_LIB(z, zlibVersion, ,
-    AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, ,
-                 AC_ERROR([zlib not installed])))
-
-# The following is for pngvalid, to ensure it catches FP errors even on
-# platforms that don't enable FP exceptions, the function appears in the math
-# library (typically), it's not an error if it is not found.
-AC_CHECK_LIB([m], [feenableexcept])
-AC_CHECK_FUNCS([feenableexcept])
-
-LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG
-LIBPNG_DEFINES=$LIBPNG_DEFINES
-AC_SUBST(LIBPNG_DEFINES)
-
-AC_MSG_CHECKING([if using Solaris linker])
-SLD=`$LD --version 2>&1 | grep Solaris`
-if test "$SLD"; then
-    have_solaris_ld=yes
-    AC_MSG_RESULT(yes)
-else
-    have_solaris_ld=no
-    AC_MSG_RESULT(no)
-fi
-AM_CONDITIONAL(HAVE_SOLARIS_LD, test "$have_solaris_ld" = "yes")
-
-AC_MSG_CHECKING([if libraries can be versioned])
-# Special case for PE/COFF platforms: ld reports
-# support for version-script, but doesn't actually
-# DO anything with it.
-case $host in
-*cygwin* | *mingw32* | *interix* )
-    have_ld_version_script=no
-    AC_MSG_RESULT(no)
-;;
-* )
-
-if test "$have_solaris_ld" = "yes"; then
-    GLD=`$LD --help < /dev/null 2>&1 | grep 'M mapfile'`
-else
-    GLD=`$LD --help < /dev/null 2>/dev/null | grep version-script`
-fi
-
-if test "$GLD"; then
-    have_ld_version_script=yes
-    AC_MSG_RESULT(yes)
-else
-    have_ld_version_script=no
-    AC_MSG_RESULT(no)
-    AC_MSG_WARN(*** You have not enabled versioned symbols.)
-fi
-;;
-esac
-
-AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
-
-if test "$have_ld_version_script" = "yes"; then
-    AC_MSG_CHECKING([for symbol prefix])
-    SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
-                   | ${CPP-${CC-gcc} -E} - 2>&1 \
-                   | ${EGREP-grep} "^PREFIX=" \
-                   | ${SED-sed} "s:^PREFIX=::"`
-    AC_SUBST(SYMBOL_PREFIX)
-    AC_MSG_RESULT($SYMBOL_PREFIX)
-fi
-
-# Substitutions for .in files
-AC_SUBST(PNGLIB_VERSION)
-AC_SUBST(PNGLIB_MAJOR)
-AC_SUBST(PNGLIB_MINOR)
-AC_SUBST(PNGLIB_RELEASE)
-
-# Additional arguments (and substitutions)
-# Allow the pkg-config directory to be set
-AC_ARG_WITH(pkgconfigdir,
-	AC_HELP_STRING([--with-pkgconfigdir],
-	[Use the specified pkgconfig dir (default is libdir/pkgconfig)]),
-	[pkgconfigdir=${withval}],
-	[pkgconfigdir='${libdir}/pkgconfig'])
-
-AC_SUBST([pkgconfigdir])
-AC_MSG_NOTICE([pkgconfig directory is ${pkgconfigdir}])
-
-# Make the *-config binary config scripts optional
-AC_ARG_WITH(binconfigs,
-	AC_HELP_STRING([--with-binconfigs],
-		[Generate shell libpng-config scripts as well as pkg-config data]
-		[@<:@default=yes@:>@]),
-	[if test "${withval}" = no; then
-		binconfigs=
-		AC_MSG_NOTICE([libpng-config scripts will not be built])
-	else
-		binconfigs='${binconfigs}'
-	fi],
-	[binconfigs='${binconfigs}'])
-AC_SUBST([binconfigs])
-
-# Because GCC by default assembles code with an executable stack, even though it
-# compiles C code with a non-executable stack, it is necessary to do a fixup
-# here (this may by GCC specific)
-AC_SUBST([AM_CCASFLAGS], [-Wa,--noexecstack])
-
-AC_ARG_ENABLE([arm-neon],
-	AC_HELP_STRING([--enable-arm-neon], [Enable ARM NEON optimizations]),
-	[if test "${enableval}" = yes; then
-		AC_DEFINE([PNG_ARM_NEON], [1], [Enable ARM NEON optimizations])
-		AC_DEFINE([PNG_ALIGNED_MEMORY_SUPPORTED], [1], [Align row buffers])
-	fi])
-AM_CONDITIONAL([PNG_ARM_NEON], [test "${enable_arm_neon:-no}" = yes])
-
-# Config files, substituting as above
-AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])
-AC_CONFIG_FILES([libpng-config:libpng-config.in],
-		[chmod +x libpng-config])
-
-AC_OUTPUT
diff --git a/extern/libpng/include/contrib/README.txt b/extern/libpng/include/contrib/README.txt
deleted file mode 100644
index bcd433d352..0000000000
--- a/extern/libpng/include/contrib/README.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-
-This "contrib" directory contains contributions which are not necessarily under
-the libpng license, although all are open source.  They are not part of
-libpng proper and are not used for building the library.
diff --git a/extern/libpng/include/contrib/gregbook/COPYING b/extern/libpng/include/contrib/gregbook/COPYING
deleted file mode 100644
index a3e9774796..0000000000
--- a/extern/libpng/include/contrib/gregbook/COPYING
+++ /dev/null
@@ -1,340 +0,0 @@
-                    GNU GENERAL PUBLIC LICENSE
-                       Version 2, June 1991
-
- Copyright (C) 1989, 1991 Free Software Foundation, Inc.
-     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
-                            Preamble
-
-  The licenses for most software are designed to take away your
-freedom to share and change it.  By contrast, the GNU General Public
-License is intended to guarantee your freedom to share and change free
-software--to make sure the software is free for all its users.  This
-General Public License applies to most of the Free Software
-Foundation's software and to any other program whose authors commit to
-using it.  (Some other Free Software Foundation software is covered by
-the GNU Library General Public License instead.)  You can apply it to
-your programs, too.
-
-  When we speak of free software, we are referring to freedom, not
-price.  Our General Public Licenses are designed to make sure that you
-have the freedom to distribute copies of free software (and charge for
-this service if you wish), that you receive source code or can get it
-if you want it, that you can change the software or use pieces of it
-in new free programs; and that you know you can do these things.
-
-  To protect your rights, we need to make restrictions that forbid
-anyone to deny you these rights or to ask you to surrender the rights.
-These restrictions translate to certain responsibilities for you if you
-distribute copies of the software, or if you modify it.
-
-  For example, if you distribute copies of such a program, whether
-gratis or for a fee, you must give the recipients all the rights that
-you have.  You must make sure that they, too, receive or can get the
-source code.  And you must show them these terms so they know their
-rights.
-
-  We protect your rights with two steps: (1) copyright the software, and
-(2) offer you this license which gives you legal permission to copy,
-distribute and/or modify the software.
-
-  Also, for each author's protection and ours, we want to make certain
-that everyone understands that there is no warranty for this free
-software.  If the software is modified by someone else and passed on, we
-want its recipients to know that what they have is not the original, so
-that any problems introduced by others will not reflect on the original
-authors' reputations.
-
-  Finally, any free program is threatened constantly by software
-patents.  We wish to avoid the danger that redistributors of a free
-program will individually obtain patent licenses, in effect making the
-program proprietary.  To prevent this, we have made it clear that any
-patent must be licensed for everyone's free use or not licensed at all.
-
-  The precise terms and conditions for copying, distribution and
-modification follow.
-
-                    GNU GENERAL PUBLIC LICENSE
-   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
-
-  0. This License applies to any program or other work which contains
-a notice placed by the copyright holder saying it may be distributed
-under the terms of this General Public License.  The "Program", below,
-refers to any such program or work, and a "work based on the Program"
-means either the Program or any derivative work under copyright law:
-that is to say, a work containing the Program or a portion of it,
-either verbatim or with modifications and/or translated into another
-language.  (Hereinafter, translation is included without limitation in
-the term "modification".)  Each licensee is addressed as "you".
-
-Activities other than copying, distribution and modification are not
-covered by this License; they are outside its scope.  The act of
-running the Program is not restricted, and the output from the Program
-is covered only if its contents constitute a work based on the
-Program (independent of having been made by running the Program).
-Whether that is true depends on what the Program does.
-
-  1. You may copy and distribute verbatim copies of the Program's
-source code as you receive it, in any medium, provided that you
-conspicuously and appropriately publish on each copy an appropriate
-copyright notice and disclaimer of warranty; keep intact all the
-notices that refer to this License and to the absence of any warranty;
-and give any other recipients of the Program a copy of this License
-along with the Program.
-
-You may charge a fee for the physical act of transferring a copy, and
-you may at your option offer warranty protection in exchange for a fee.
-
-  2. You may modify your copy or copies of the Program or any portion
-of it, thus forming a work based on the Program, and copy and
-distribute such modifications or work under the terms of Section 1
-above, provided that you also meet all of these conditions:
-
-    a) You must cause the modified files to carry prominent notices
-    stating that you changed the files and the date of any change.
-
-    b) You must cause any work that you distribute or publish, that in
-    whole or in part contains or is derived from the Program or any
-    part thereof, to be licensed as a whole at no charge to all third
-    parties under the terms of this License.
-
-    c) If the modified program normally reads commands interactively
-    when run, you must cause it, when started running for such
-    interactive use in the most ordinary way, to print or display an
-    announcement including an appropriate copyright notice and a
-    notice that there is no warranty (or else, saying that you provide
-    a warranty) and that users may redistribute the program under
-    these conditions, and telling the user how to view a copy of this
-    License.  (Exception: if the Program itself is interactive but
-    does not normally print such an announcement, your work based on
-    the Program is not required to print an announcement.)
-
-These requirements apply to the modified work as a whole.  If
-identifiable sections of that work are not derived from the Program,
-and can be reasonably considered independent and separate works in
-themselves, then this License, and its terms, do not apply to those
-sections when you distribute them as separate works.  But when you
-distribute the same sections as part of a whole which is a work based
-on the Program, the distribution of the whole must be on the terms of
-this License, whose permissions for other licensees extend to the
-entire whole, and thus to each and every part regardless of who wrote it.
-
-Thus, it is not the intent of this section to claim rights or contest
-your rights to work written entirely by you; rather, the intent is to
-exercise the right to control the distribution of derivative or
-collective works based on the Program.
-
-In addition, mere aggregation of another work not based on the Program
-with the Program (or with a work based on the Program) on a volume of
-a storage or distribution medium does not bring the other work under
-the scope of this License.
-
-  3. You may copy and distribute the Program (or a work based on it,
-under Section 2) in object code or executable form under the terms of
-Sections 1 and 2 above provided that you also do one of the following:
-
-    a) Accompany it with the complete corresponding machine-readable
-    source code, which must be distributed under the terms of Sections
-    1 and 2 above on a medium customarily used for software interchange; or,
-
-    b) Accompany it with a written offer, valid for at least three
-    years, to give any third party, for a charge no more than your
-    cost of physically performing source distribution, a complete
-    machine-readable copy of the corresponding source code, to be
-    distributed under the terms of Sections 1 and 2 above on a medium
-    customarily used for software interchange; or,
-
-    c) Accompany it with the information you received as to the offer
-    to distribute corresponding source code.  (This alternative is
-    allowed only for noncommercial distribution and only if you
-    received the program in object code or executable form with such
-    an offer, in accord with Subsection b above.)
-
-The source code for a work means the preferred form of the work for
-making modifications to it.  For an executable work, complete source
-code means all the source code for all modules it contains, plus any
-associated interface definition files, plus the scripts used to
-control compilation and installation of the executable.  However, as a
-special exception, the source code distributed need not include
-anything that is normally distributed (in either source or binary
-form) with the major components (compiler, kernel, and so on) of the
-operating system on which the executable runs, unless that component
-itself accompanies the executable.
-
-If distribution of executable or object code is made by offering
-access to copy from a designated place, then offering equivalent
-access to copy the source code from the same place counts as
-distribution of the source code, even though third parties are not
-compelled to copy the source along with the object code.
-
-  4. You may not copy, modify, sublicense, or distribute the Program
-except as expressly provided under this License.  Any attempt
-otherwise to copy, modify, sublicense or distribute the Program is
-void, and will automatically terminate your rights under this License.
-However, parties who have received copies, or rights, from you under
-this License will not have their licenses terminated so long as such
-parties remain in full compliance.
-
-  5. You are not required to accept this License, since you have not
-signed it.  However, nothing else grants you permission to modify or
-distribute the Program or its derivative works.  These actions are
-prohibited by law if you do not accept this License.  Therefore, by
-modifying or distributing the Program (or any work based on the
-Program), you indicate your acceptance of this License to do so, and
-all its terms and conditions for copying, distributing or modifying
-the Program or works based on it.
-
-  6. Each time you redistribute the Program (or any work based on the
-Program), the recipient automatically receives a license from the
-original licensor to copy, distribute or modify the Program subject to
-these terms and conditions.  You may not impose any further
-restrictions on the recipients' exercise of the rights granted herein.
-You are not responsible for enforcing compliance by third parties to
-this License.
-
-  7. If, as a consequence of a court judgment or allegation of patent
-infringement or for any other reason (not limited to patent issues),
-conditions are imposed on you (whether by court order, agreement or
-otherwise) that contradict the conditions of this License, they do not
-excuse you from the conditions of this License.  If you cannot
-distribute so as to satisfy simultaneously your obligations under this
-License and any other pertinent obligations, then as a consequence you
-may not distribute the Program at all.  For example, if a patent
-license would not permit royalty-free redistribution of the Program by
-all those who receive copies directly or indirectly through you, then
-the only way you could satisfy both it and this License would be to
-refrain entirely from distribution of the Program.
-
-If any portion of this section is held invalid or unenforceable under
-any particular circumstance, the balance of the section is intended to
-apply and the section as a whole is intended to apply in other
-circumstances.
-
-It is not the purpose of this section to induce you to infringe any
-patents or other property right claims or to contest validity of any
-such claims; this section has the sole purpose of protecting the
-integrity of the free software distribution system, which is
-implemented by public license practices.  Many people have made
-generous contributions to the wide range of software distributed
-through that system in reliance on consistent application of that
-system; it is up to the author/donor to decide if he or she is willing
-to distribute software through any other system and a licensee cannot
-impose that choice.
-
-This section is intended to make thoroughly clear what is believed to
-be a consequence of the rest of this License.
-
-  8. If the distribution and/or use of the Program is restricted in
-certain countries either by patents or by copyrighted interfaces, the
-original copyright holder who places the Program under this License
-may add an explicit geographical distribution limitation excluding
-those countries, so that distribution is permitted only in or among
-countries not thus excluded.  In such case, this License incorporates
-the limitation as if written in the body of this License.
-
-  9. The Free Software Foundation may publish revised and/or new versions
-of the General Public License from time to time.  Such new versions will
-be similar in spirit to the present version, but may differ in detail to
-address new problems or concerns.
-
-Each version is given a distinguishing version number.  If the Program
-specifies a version number of this License which applies to it and "any
-later version", you have the option of following the terms and conditions
-either of that version or of any later version published by the Free
-Software Foundation.  If the Program does not specify a version number of
-this License, you may choose any version ever published by the Free Software
-Foundation.
-
-  10. If you wish to incorporate parts of the Program into other free
-programs whose distribution conditions are different, write to the author
-to ask for permission.  For software which is copyrighted by the Free
-Software Foundation, write to the Free Software Foundation; we sometimes
-make exceptions for this.  Our decision will be guided by the two goals
-of preserving the free status of all derivatives of our free software and
-of promoting the sharing and reuse of software generally.
-
-                            NO WARRANTY
-
-  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
-FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
-OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
-PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
-OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
-TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
-PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
-REPAIR OR CORRECTION.
-
-  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
-REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
-INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
-OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
-TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
-YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
-PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
-POSSIBILITY OF SUCH DAMAGES.
-
-                     END OF TERMS AND CONDITIONS
-
-            How to Apply These Terms to Your New Programs
-
-  If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
-  To do so, attach the following notices to the program.  It is safest
-to attach them to the start of each source file to most effectively
-convey the exclusion of warranty; and each file should have at least
-the "copyright" line and a pointer to where the full notice is found.
-
-    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-
-Also add information on how to contact you by electronic and paper mail.
-
-If the program is interactive, make it output a short notice like this
-when it starts in an interactive mode:
-
-    Gnomovision version 69, Copyright (C) year  name of author
-    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
-    This is free software, and you are welcome to redistribute it
-    under certain conditions; type `show c' for details.
-
-The hypothetical commands `show w' and `show c' should show the appropriate
-parts of the General Public License.  Of course, the commands you use may
-be called something other than `show w' and `show c'; they could even be
-mouse-clicks or menu items--whatever suits your program.
-
-You should also get your employer (if you work as a programmer) or your
-school, if any, to sign a "copyright disclaimer" for the program, if
-necessary.  Here is a sample; alter the names:
-
-  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
-  `Gnomovision' (which makes passes at compilers) written by James Hacker.
-
-  <signature of Ty Coon>, 1 April 1989
-  Ty Coon, President of Vice
-
-This General Public License does not permit incorporating your program into
-proprietary programs.  If your program is a subroutine library, you may
-consider it more useful to permit linking proprietary applications with the
-library.  If this is what you want to do, use the GNU Library General
-Public License instead of this License.
diff --git a/extern/libpng/include/contrib/gregbook/LICENSE b/extern/libpng/include/contrib/gregbook/LICENSE
deleted file mode 100644
index d9567178cb..0000000000
--- a/extern/libpng/include/contrib/gregbook/LICENSE
+++ /dev/null
@@ -1,50 +0,0 @@
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------
diff --git a/extern/libpng/include/contrib/gregbook/Makefile.mingw32 b/extern/libpng/include/contrib/gregbook/Makefile.mingw32
deleted file mode 100644
index e70a59aef2..0000000000
--- a/extern/libpng/include/contrib/gregbook/Makefile.mingw32
+++ /dev/null
@@ -1,130 +0,0 @@
-# Sample makefile for rpng-win / rpng2-win / wpng using mingw32-gcc and make.
-# Greg Roelofs
-# Last modified:  2 June 2007
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
-#	generally for sale anymore, but it's the thought that counts,
-#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
-#
-# Invoke this makefile from a DOS-prompt window via:
-#
-#	make -f Makefile.mingw32
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are in subdirectories at the same level as the current subdirectory
-# (as indicated by the PNGDIR and ZDIR macros below).  It makes no assumptions
-# at all about the mingw32 installation tree (W32DIR).  Edit as appropriate.
-#
-# Note that the names of the dynamic and static libpng and zlib libraries
-# used below may change in later releases of the libraries.  This makefile
-# builds both statically and dynamically linked executables by default.
-# (You need only one set, but for testing it can be handy to have both.)
-
-
-# macros --------------------------------------------------------------------
-
-#PNGDIR = ../..#		for libpng-x.y.z/contrib/gregbook builds
-PNGDIR = ../libpng-win32
-PNGINC = -I$(PNGDIR)
-PNGLIBd = $(PNGDIR)/libpng.dll.a	# dynamically linked
-PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
-
-#ZDIR = ../../../zlib-win32#	for libpng-x.y.z/contrib/gregbook builds
-ZDIR = ../zlib-win32
-ZINC = -I$(ZDIR)
-ZLIBd = $(ZDIR)/libzdll.a
-ZLIBs = $(ZDIR)/libz.a
-
-# change this to be the path where mingw32 installs its stuff:
-W32DIR =
-#W32DIR = /usr/local/cross-tools/i386-mingw32msvc
-W32INC = -I$(W32DIR)/include
-W32LIB = $(W32DIR)/lib/libuser32.a $(W32DIR)/lib/libgdi32.a
-
-CC = gcc
-#CC = i386-mingw32msvc-gcc #	e.g., Linux -> Win32 cross-compilation
-LD = $(CC)
-RM = rm -f
-CFLAGS = -O -Wall $(INCS) $(MINGW_CCFLAGS)
-# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
-# [-ansi, -pedantic and -W can also be used]
-LDFLAGS = $(MINGW_LDFLAGS)
-O = .o
-E = .exe
-
-INCS = $(PNGINC) $(ZINC) $(W32INC)
-RLIBSd = $(PNGLIBd) $(ZLIBd) $(W32LIB) -lm
-RLIBSs = $(PNGLIBs) $(ZLIBs) $(W32LIB) -lm
-WLIBSd = $(PNGLIBd) $(ZLIBd)
-WLIBSs = $(PNGLIBs) $(ZLIBs)
-
-RPNG   = rpng-win
-RPNG2  = rpng2-win
-WPNG   = wpng
-
-ROBJSd  = $(RPNG)$(O) readpng.pic$(O)
-ROBJS2d = $(RPNG2)$(O) readpng2.pic$(O)
-WOBJSd  = $(WPNG)$(O) writepng.pic$(O)
-
-RPNGs  = $(RPNG)-static
-RPNG2s = $(RPNG2)-static
-WPNGs  = $(WPNG)-static
-
-ROBJSs  = $(RPNG)$(O) readpng$(O)
-ROBJS2s = $(RPNG2)$(O) readpng2$(O)
-WOBJSs  = $(WPNG)$(O) writepng$(O)
-
-STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
-DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-%.pic$(O): %.c
-	$(CC) -c $(CFLAGS) -DPNG_BUILD_DLL -o $@ $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNGs)$(E): $(ROBJSs)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJSs) $(RLIBSs)
-
-$(RPNG)$(E): $(ROBJSd)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJSd) $(RLIBSd)
-
-$(RPNG2s)$(E): $(ROBJS2s)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2s) $(RLIBSs)
-
-$(RPNG2)$(E): $(ROBJS2d)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2d) $(RLIBSd)
-
-$(WPNGs)$(E): $(WOBJSs)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJSs) $(WLIBSs)
-
-$(WPNG)$(E): $(WOBJSd)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJSd) $(WLIBSd)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O) readpng.pic$(O):	readpng.c readpng.h
-readpng2$(O) readpng2.pic$(O):	readpng2.c readpng2.h
-writepng$(O) writepng.pic$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-	$(RM) $(EXES)
-	$(RM) $(ROBJSs) $(ROBJS2s) $(WOBJSs)
-	$(RM) $(ROBJSd) $(ROBJS2d) $(WOBJSd)
diff --git a/extern/libpng/include/contrib/gregbook/Makefile.sgi b/extern/libpng/include/contrib/gregbook/Makefile.sgi
deleted file mode 100644
index 91623acf06..0000000000
--- a/extern/libpng/include/contrib/gregbook/Makefile.sgi
+++ /dev/null
@@ -1,104 +0,0 @@
-# Sample makefile for rpng-x / rpng2-x / wpng for SGI using cc and make.
-# Greg Roelofs
-# Last modified:  7 March 2002
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Buy some for friends
-#	and family, too.  (Not that this is a blatant plug or anything.)
-#
-# Invoke this makefile from a shell prompt in the usual way; for example:
-#
-#	make -f Makefile.sgi
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are both installed in /usr/local/{include,lib} (as indicated by the
-# PNG* and Z* macros below).  Edit as appropriate--choose only ONE each of
-# the PNGINC, PNGLIB, ZINC and ZLIB lines.
-#
-# This makefile builds dynamically linked executables (against libpng and zlib,
-# that is), but that can be changed by uncommenting the appropriate PNGLIB and
-# ZLIB lines.
-
-
-# macros --------------------------------------------------------------------
-
-PNGINC = -I/usr/local/include/libpng15
-PNGLIB = -L/usr/local/lib -lpng15	  # dynamically linked against libpng
-#PNGLIB = /usr/local/lib/libpng15.a # statically linked against libpng
-# or:
-#PNGINC = -I../..
-#PNGLIB = -L../.. -lpng
-#PNGLIB = ../../libpng.a
-
-ZINC = -I/usr/local/include
-ZLIB = -L/usr/local/lib -lz		# dynamically linked against zlib
-#ZLIB = /usr/local/lib/libz.a		# statically linked against zlib
-#ZINC = -I../zlib
-#ZLIB = -L../zlib -lz
-#ZLIB = ../../../zlib/libz.a
-
-XINC = -I/usr/include/X11		# old-style, stock X distributions
-XLIB = -L/usr/lib/X11 -lX11
-#XINC = -I/usr/openwin/include    	# Sun workstations (OpenWindows)
-#XLIB = -L/usr/openwin/lib -lX11
-#XINC = -I/usr/X11R6/include		# new X distributions (XFree86, etc.)
-#XLIB = -L/usr/X11R6/lib -lX11
-
-INCS = $(PNGINC) $(ZINC) $(XINC)
-RLIBS = $(PNGLIB) $(ZLIB) $(XLIB) -lm
-WLIBS = $(PNGLIB) $(ZLIB)
-
-CC = cc
-LD = cc
-RM = rm -f
-# ABI must be the same as that used to build libpng.
-ABI=
-CFLAGS = $(ABI) -O -fullwarn $(INCS)
-LDFLAGS = $(ABI)
-O = .o
-E =
-
-RPNG  = rpng-x
-RPNG2 = rpng2-x
-WPNG  = wpng
-
-ROBJS  = $(RPNG)$(O) readpng$(O)
-ROBJS2 = $(RPNG2)$(O) readpng2$(O)
-WOBJS  = $(WPNG)$(O) writepng$(O)
-
-EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNG)$(E): $(ROBJS)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBS)
-
-$(RPNG2)$(E): $(ROBJS2)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBS)
-
-$(WPNG)$(E): $(WOBJS)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBS)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O):	readpng.c readpng.h
-readpng2$(O):	readpng2.c readpng2.h
-writepng$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/extern/libpng/include/contrib/gregbook/Makefile.unx b/extern/libpng/include/contrib/gregbook/Makefile.unx
deleted file mode 100644
index b52d8b6aa6..0000000000
--- a/extern/libpng/include/contrib/gregbook/Makefile.unx
+++ /dev/null
@@ -1,132 +0,0 @@
-# Sample makefile for rpng-x / rpng2-x / wpng using gcc and make.
-# Greg Roelofs
-# Last modified:  2 June 2007
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
-#	generally for sale anymore, but it's the thought that counts,
-#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
-#
-# Invoke this makefile from a shell prompt in the usual way; for example:
-#
-#	make -f Makefile.unx
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are installed in /usr/local/{include,lib} or as otherwise indicated by
-# the PNG* and Z* macros below.  Edit as appropriate--choose only ONE each of
-# the PNGINC, PNGLIBd, PNGLIBs, ZINC, ZLIBd and ZLIBs lines.
-#
-# This makefile builds both dynamically and statically linked executables
-# (against libpng and zlib, that is), but that can be changed by modifying
-# the "EXES =" line.  (You need only one set, but for testing it can be handy
-# to have both.)
-
-
-# macros --------------------------------------------------------------------
-
-#PNGDIR = /usr/local/lib
-#PNGINC = -I/usr/local/include/libpng15
-#PNGLIBd = -L$(PNGDIR) -lpng15 # dynamically linked, installed libpng
-#PNGLIBs = $(PNGDIR)/libpng15.a # statically linked, installed libpng
-# or:
-PNGDIR = ../..#	this one is for libpng-x.y.z/contrib/gregbook builds
-#PNGDIR = ../libpng
-PNGINC = -I$(PNGDIR)
-PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng15	# dynamically linked
-PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
-
-ZDIR = /usr/local/lib
-#ZDIR = /usr/lib64
-ZINC = -I/usr/local/include
-ZLIBd = -L$(ZDIR) -lz			# dynamically linked against zlib
-ZLIBs = $(ZDIR)/libz.a			# statically linked against zlib
-# or:
-#ZDIR = ../zlib
-#ZINC = -I$(ZDIR)
-#ZLIBd = -Wl,-rpath,$(ZDIR) -L$(ZDIR) -lz  # -rpath allows in-place testing
-#ZLIBs = $(ZDIR)/libz.a
-
-#XINC = -I/usr/include			# old-style, stock X distributions
-#XLIB = -L/usr/lib/X11 -lX11		#  (including SGI IRIX)
-#XINC = -I/usr/openwin/include		# Sun workstations (OpenWindows)
-#XLIB = -L/usr/openwin/lib -lX11
-XINC = -I/usr/X11R6/include		# new X distributions (X.org, etc.)
-XLIB = -L/usr/X11R6/lib -lX11
-#XLIB = -L/usr/X11R6/lib64 -lX11	# e.g., Red Hat on AMD64
-
-INCS = $(PNGINC) $(ZINC) $(XINC)
-RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
-RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
-WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
-WLIBSs = $(PNGLIBs) $(ZLIBs)
-
-CC = gcc
-LD = gcc
-RM = rm -f
-CFLAGS = -O -Wall $(INCS) -DFEATURE_LOOP
-# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
-# [-ansi, -pedantic and -W can also be used]
-LDFLAGS =
-O = .o
-E =
-
-RPNG   = rpng-x
-RPNG2  = rpng2-x
-WPNG   = wpng
-
-RPNGs  = $(RPNG)-static
-RPNG2s = $(RPNG2)-static
-WPNGs  = $(WPNG)-static
-
-ROBJS  = $(RPNG)$(O) readpng$(O)
-ROBJS2 = $(RPNG2)$(O) readpng2$(O)
-WOBJS  = $(WPNG)$(O) writepng$(O)
-
-STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
-DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNGs)$(E): $(ROBJS)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSs)
-
-$(RPNG)$(E): $(ROBJS)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSd)
-
-$(RPNG2s)$(E): $(ROBJS2)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSs)
-
-$(RPNG2)$(E): $(ROBJS2)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSd)
-
-$(WPNGs)$(E): $(WOBJS)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSs)
-
-$(WPNG)$(E): $(WOBJS)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSd)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O):	readpng.c readpng.h
-readpng2$(O):	readpng2.c readpng2.h
-writepng$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/extern/libpng/include/contrib/gregbook/Makefile.w32 b/extern/libpng/include/contrib/gregbook/Makefile.w32
deleted file mode 100644
index 41cfb231a2..0000000000
--- a/extern/libpng/include/contrib/gregbook/Makefile.w32
+++ /dev/null
@@ -1,113 +0,0 @@
-# Sample makefile for rpng-win / rpng2-win / wpng using MSVC and NMAKE.
-# Greg Roelofs
-# Last modified:  2 June 2007
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
-#	generally for sale anymore, but it's the thought that counts,
-#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
-#
-# Invoke this makefile from a DOS prompt window via:
-#
-#	%devstudio%\vc\bin\vcvars32.bat
-#	nmake -nologo -f Makefile.w32
-#
-# where %devstudio% is the installation directory for MSVC / DevStudio.  If
-# you get "environment out of space" errors, create a desktop shortcut with
-# "c:\windows\command.com /e:4096" as the program command line and set the
-# working directory to this directory.  Then double-click to open the new
-# DOS-prompt window with a bigger environment and retry the commands above.
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are in subdirectories at the same level as the current subdirectory
-# (as indicated by the PNGPATH and ZPATH macros below).  Edit as appropriate.
-#
-# Note that the names of the dynamic and static libpng and zlib libraries
-# used below may change in later releases of the libraries.  This makefile
-# builds statically linked executables, but that can be changed by uncom-
-# menting the appropriate PNGLIB and ZLIB lines.
-
-!include <ntwin32.mak>
-
-
-# macros --------------------------------------------------------------------
-
-PNGPATH = ../libpng
-PNGINC = -I$(PNGPATH)
-#PNGLIB = $(PNGPATH)/pngdll.lib
-PNGLIB = $(PNGPATH)/libpng.lib
-
-ZPATH = ../zlib
-ZINC = -I$(ZPATH)
-#ZLIB = $(ZPATH)/zlibdll.lib
-ZLIB = $(ZPATH)/zlibstat.lib
-
-WINLIBS = -defaultlib:user32.lib gdi32.lib
-# ["real" apps may also need comctl32.lib, comdlg32.lib, winmm.lib, etc.]
-
-INCS = $(PNGINC) $(ZINC)
-RLIBS = $(PNGLIB) $(ZLIB) $(WINLIBS)
-WLIBS = $(PNGLIB) $(ZLIB)
-
-CC = cl
-LD = link
-RM = del
-CFLAGS = -nologo -O -W3 $(INCS) $(cvars)
-# [note that -W3 is an MSVC-specific compilation flag ("all warnings on")]
-# [see %devstudio%\vc\include\win32.mak for cvars macro definition]
-O = .obj
-E = .exe
-
-RLDFLAGS = -nologo -subsystem:windows
-WLDFLAGS = -nologo
-
-RPNG  = rpng-win
-RPNG2 = rpng2-win
-WPNG  = wpng
-
-ROBJS  = $(RPNG)$(O) readpng$(O)
-ROBJS2 = $(RPNG2)$(O) readpng2$(O)
-WOBJS  = $(WPNG)$(O) writepng$(O)
-
-EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNG)$(E): $(ROBJS)
-	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS) $(RLIBS)
-
-$(RPNG2)$(E): $(ROBJS2)
-	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS2) $(RLIBS)
-
-$(WPNG)$(E): $(WOBJS)
-	$(LD) $(WLDFLAGS) -out:$@ $(WOBJS) $(WLIBS)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O):	readpng.c readpng.h
-readpng2$(O):	readpng2.c readpng2.h
-writepng$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-#	ideally we could just do this:
-#	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
-#	...but the Windows "DEL" command is none too bright, so:
-	$(RM) r*$(E)
-	$(RM) w*$(E)
-	$(RM) r*$(O)
-	$(RM) w*$(O)
diff --git a/extern/libpng/include/contrib/gregbook/README b/extern/libpng/include/contrib/gregbook/README
deleted file mode 100644
index 7b1f6a3ea6..0000000000
--- a/extern/libpng/include/contrib/gregbook/README
+++ /dev/null
@@ -1,186 +0,0 @@
-                     ===========================
-                      PNG: The Definitive Guide
-                     ===========================
-
-                             Source Code
-
-Chapters 13, 14 and 15 of "PNG: The Definitive Guide" discuss three free,
-cross-platform demo programs that show how to use the libpng reference
-library:  rpng, rpng2 and wpng.  rpng and rpng2 are viewers; the first is
-a very simple example that that shows how a standard file-viewer might use
-libpng, while the second is designed to process streaming data and shows
-how a web browser might be written.  wpng is a simple command-line program
-that reads binary PGM and PPM files (the ``raw'' grayscale and RGB subsets
-of PBMPLUS/NetPBM) and converts them to PNG.
-
-The source code for all three demo programs currently compiles under
-Unix, OpenVMS, and 32-bit Windows.  (Special thanks to Martin Zinser,
-zinser@decus.de, for making the necessary changes for OpenVMS and for
-providing an appropriate build script.)  Build instructions can be found
-below.
-
-Files:
-
-   README             this file
-   LICENSE            terms of distribution and reuse (BSD-like or GNU GPL)
-   COPYING            GNU General Public License (GPL)
-
-   Makefile.unx       Unix makefile
-   Makefile.w32       Windows (MSVC) makefile
-   makevms.com        OpenVMS build script
-
-   rpng-win.c         Windows front end for the basic viewer
-   rpng-x.c           X Window System (Unix, OpenVMS) front end
-   readpng.c          generic back end for the basic viewer
-   readpng.h          header file for the basic viewer
-
-   rpng2-win.c        Windows front end for the progressive viewer
-   rpng2-x.c          X front end for the progressive viewer
-   readpng2.c         generic back end for the progressive viewer
-   readpng2.h         header file for the progressive viewer
-
-   wpng.c             generic (text) front end for the converter
-   writepng.c         generic back end for the converter
-   writepng.h         header file for the converter
-
-   toucan.png         transparent PNG for testing (by Stefan Schneider)
-
-Note that, although the programs are designed to be functional, their
-primary purpose is to illustrate how to use libpng to add PNG support to
-other programs.  As such, their user interfaces are crude and definitely
-are not intended for everyday use.
-
-Please see http://www.libpng.org/pub/png/pngbook.html for further infor-
-mation and links to the latest version of the source code, and Chapters
-13-15 of the book for detailed discussion of the three programs.
-
-Greg Roelofs
-http://pobox.com/~newt/greg_contact.html
-16 March 2008
-
-
-BUILD INSTRUCTIONS
-
- - Prerequisites (in order of compilation):
-
-      - zlib            http://zlib.net/
-      - libpng          http://www.libpng.org/pub/png/libpng.html
-      - pngbook         http://www.libpng.org/pub/png/book/sources.html
-
-     The pngbook demo programs are explicitly designed to demonstrate proper
-     coding techniques for using the libpng reference library.  As a result,
-     you need to download and build both zlib (on which libpng depends) and
-     libpng.  A common build setup is to place the zlib, libpng and pngbook
-     subdirectory trees ("folders") in the same parent directory.  Then the
-     libpng build can refer to files in ../zlib (or ..\zlib or [-.zlib]),
-     and similarly for the pngbook build.
-
-     Note that all three packages are designed to be built from a command
-     line by default; those who wish to use a graphical or other integrated
-     development environments are on their own.
-
-
- - Unix:
-
-     Unpack the latest pngbook sources (which should correspond to this
-     README file) into a directory and change into that directory.
-
-     Copy Makefile.unx to Makefile and edit the PNG* and Z* variables
-     appropriately (possibly also the X* variables if necessary).
-
-     make
-
-     There is no "install" target, so copy the three executables somewhere
-     in your path or run them from the current directory.  All three will
-     print a basic usage screen when run without any command-line arguments;
-     see the book for more details.
-
-
- - Windows:
-
-     Unpack the latest pngbook sources (which should correspond to this
-     README file) into a folder, open a "DOS shell" or "command prompt"
-     or equivalent command-line window, and cd into the folder where you
-     unpacked the source code.
-
-     For MSVC, set up the necessary environment variables by invoking
-
-        %devstudio%\vc\bin\vcvars32.bat
-
-     where where %devstudio% is the installation directory for MSVC /
-     DevStudio.  If you get "environment out of space" errors under 95/98,
-     create a desktop shortcut with "c:\windows\command.com /e:4096" as
-     the program command line and set the working directory to the pngbook
-     directory.  Then double-click to open the new DOS-prompt window with
-     a bigger environment and retry the commands above.
-
-     Copy Makefile.w32 to Makefile and edit the PNGPATH and ZPATH variables
-     appropriately (possibly also the "INC" and "LIB" variables if needed).
-     Note that the names of the dynamic and static libpng and zlib libraries
-     used in the makefile may change in later releases of the libraries.
-     Also note that, as of libpng version 1.0.5, MSVC DLL builds do not work.
-     This makefile therefore builds statically linked executables, but if
-     the DLL problems ever get fixed, uncommenting the appropriate PNGLIB
-     and ZLIB lines will build dynamically linked executables instead.
-
-     Do the build by typing
-
-        nmake
-
-     The result should be three executables:  rpng-win.exe, rpng2-win.exe,
-     and wpng.exe.  Copy them somewhere in your PATH or run them from the
-     current folder.  Like the Unix versions, the two windowed programs
-     (rpng and rpng2) now display a usage screen in a console window when
-     invoked without command-line arguments; this is new behavior as of
-     the June 2001 release.  Note that the programs use the Unix-style "-"
-     character to specify options, instead of the more common DOS/Windows
-     "/" character.  (For example:  "rpng2-win -bgpat 4 foo.png", not
-     "rpng2-win /bgpat 4 foo.png")
-
-
- - OpenVMS:
-
-     Unpack the pngbook sources into a subdirectory and change into that
-     subdirectory.
-
-     Edit makevms.com appropriately, specifically the zpath and pngpath
-     variables.
-
-     @makevms
-
-     To run the programs, they probably first need to be set up as "foreign
-     symbols," with "disk" and "dir" set appropriately:
-
-     $ rpng  == "$disk:[dir]rpng-x.exe"
-     $ rpng2 == "$disk:[dir]rpng2-x.exe"
-     $ wpng  == "$disk:[dir]wpng.exe"
-
-     All three will print a basic usage screen when run without any command-
-     line arguments; see the book for more details.  Note that the options
-     style is Unix-like, i.e., preceded by "-" rather than "/".
-
-
-RUNNING THE PROGRAMS:  (VERY) BRIEF INTRO
-
-     rpng is a simple PNG viewer that can display transparent PNGs with a
-     specified background color; for example,
-
-        rpng -bgcolor \#ff0000 toucan.png
-
-     would display the image with a red background.  rpng2 is a progressive
-     viewer that simulates a web browser in some respects; it can display
-     images against either a background color or a dynamically generated
-     background image.  For example:
-
-        rpng2 -bgpat 16 toucan.png
-
-     wpng is a purely command-line image converter from binary PBMPLUS/NetPBM
-     format (.pgm or .ppm) to PNG; for example,
-
-        wpng -time < toucan-notrans.ppm > toucan-notrans.png
-
-     would convert the specified PPM file (using redirection) to PNG, auto-
-     matically setting the PNG modification-time chunk.
-
-     All options can be abbreviated to the shortest unique value; for example,
-     "-bgc" for -bgcolor (versus "-bgp" for -bgpat), or "-g" for -gamma.
diff --git a/extern/libpng/include/contrib/gregbook/makevms.com b/extern/libpng/include/contrib/gregbook/makevms.com
deleted file mode 100644
index f32bcaba7f..0000000000
--- a/extern/libpng/include/contrib/gregbook/makevms.com
+++ /dev/null
@@ -1,132 +0,0 @@
-$!------------------------------------------------------------------------------
-$! make "PNG: The Definitive Guide" demo programs (for X) under OpenVMS
-$!
-$! Script created by Martin Zinser for libpng; modified by Greg Roelofs
-$! for standalone pngbook source distribution.
-$!
-$!
-$!    Set locations where zlib and libpng sources live.
-$!
-$ zpath   = ""
-$ pngpath = ""
-$!
-$ if f$search("[---.zlib]zlib.h").nes."" then zpath = "[---.zlib]"
-$ if f$search("[--]png.h").nes."" then pngpath = "[--]"
-$!
-$ if f$search("[-.zlib]zlib.h").nes."" then zpath = "[-.zlib]"
-$ if f$search("[-.libpng]png.h").nes."" then pngpath = "[-.libpng]"
-$!
-$ if zpath .eqs. ""
-$ then
-$   write sys$output "zlib include not found. Exiting..."
-$   exit 2
-$ endif
-$!
-$ if pngpath .eqs. ""
-$ then
-$   write sys$output "libpng include not found. Exiting..."
-$   exit 2
-$ endif
-$!
-$!    Look for the compiler used.
-$!
-$ ccopt="/include=(''zpath',''pngpath')"
-$ if f$getsyi("HW_MODEL").ge.1024
-$ then
-$  ccopt = "/prefix=all"+ccopt
-$  comp  = "__decc__=1"
-$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$ else
-$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
-$   then
-$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
-$     then
-$      comp  = "__gcc__=1"
-$      CC :== GCC
-$     else
-$      comp = "__vaxc__=1"
-$     endif
-$   else
-$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
-$    ccopt = "/decc/prefix=all"+ccopt
-$    comp  = "__decc__=1"
-$  endif
-$ endif
-$ open/write lopt lib.opt
-$ write lopt "''pngpath'libpng.olb/lib"
-$ write lopt "''zpath'libz.olb/lib"
-$ close lopt
-$ open/write xopt x11.opt
-$ write xopt "sys$library:decw$xlibshr.exe/share"
-$ close xopt
-$!
-$!    Build 'em.
-$!
-$ write sys$output "Compiling PNG book programs ..."
-$   CALL MAKE readpng.OBJ "cc ''CCOPT' readpng" -
-	readpng.c readpng.h
-$   CALL MAKE readpng2.OBJ "cc ''CCOPT' readpng2" -
-	readpng2.c readpng2.h
-$   CALL MAKE writepng.OBJ "cc ''CCOPT' writepng" -
-	writepng.c writepng.h
-$   write sys$output "Building rpng-x..."
-$   CALL MAKE rpng-x.OBJ "cc ''CCOPT' rpng-x" -
-	rpng-x.c readpng.h
-$   call make rpng-x.exe -
-	"LINK rpng-x,readpng,lib.opt/opt,x11.opt/opt" -
-	rpng-x.obj readpng.obj
-$   write sys$output "Building rpng2-x..."
-$   CALL MAKE rpng2-x.OBJ "cc ''CCOPT' rpng2-x" -
-	rpng2-x.c readpng2.h
-$   call make rpng2-x.exe -
-	"LINK rpng2-x,readpng2,lib.opt/opt,x11.opt/opt" -
-	rpng2-x.obj readpng2.obj
-$   write sys$output "Building wpng..."
-$   CALL MAKE wpng.OBJ "cc ''CCOPT' wpng" -
-	wpng.c writepng.h
-$   call make wpng.exe -
-	"LINK wpng,writepng,lib.opt/opt" -
-	wpng.obj writepng.obj
-$ exit
-$!
-$!
-$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
-$ V = 'F$Verify(0)
-$! P1 = What we are trying to make
-$! P2 = Command to make it
-$! P3 - P8  What it depends on
-$
-$ If F$Search(P1) .Eqs. "" Then Goto Makeit
-$ Time = F$CvTime(F$File(P1,"RDT"))
-$arg=3
-$Loop:
-$       Argument = P'arg
-$       If Argument .Eqs. "" Then Goto Exit
-$       El=0
-$Loop2:
-$       File = F$Element(El," ",Argument)
-$       If File .Eqs. " " Then Goto Endl
-$       AFile = ""
-$Loop3:
-$       OFile = AFile
-$       AFile = F$Search(File)
-$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
-$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
-$       Goto Loop3
-$NextEL:
-$       El = El + 1
-$       Goto Loop2
-$EndL:
-$ arg=arg+1
-$ If arg .Le. 8 Then Goto Loop
-$ Goto Exit
-$
-$Makeit:
-$ VV=F$VERIFY(0)
-$ write sys$output P2
-$ 'P2
-$ VV='F$Verify(VV)
-$Exit:
-$ If V Then Set Verify
-$ENDSUBROUTINE
diff --git a/extern/libpng/include/contrib/gregbook/readpng.c b/extern/libpng/include/contrib/gregbook/readpng.c
deleted file mode 100644
index df42c301b3..0000000000
--- a/extern/libpng/include/contrib/gregbook/readpng.c
+++ /dev/null
@@ -1,311 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                              readpng.c
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "png.h"        /* libpng header; includes zlib.h */
-#include "readpng.h"    /* typedefs, common macros, public prototypes */
-
-/* future versions of libpng will provide this macro: */
-#ifndef png_jmpbuf
-#  define png_jmpbuf(png_ptr)   ((png_ptr)->jmpbuf)
-#endif
-
-
-static png_structp png_ptr = NULL;
-static png_infop info_ptr = NULL;
-
-png_uint_32  width, height;
-int  bit_depth, color_type;
-uch  *image_data = NULL;
-
-
-void readpng_version_info(void)
-{
-    fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
-      PNG_LIBPNG_VER_STRING, png_libpng_ver);
-    fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
-      ZLIB_VERSION, zlib_version);
-}
-
-
-/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
-
-int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
-{
-    uch sig[8];
-
-
-    /* first do a quick check that the file really is a PNG image; could
-     * have used slightly more general png_sig_cmp() function instead */
-
-    fread(sig, 1, 8, infile);
-    if (png_sig_cmp(sig, 0, 8))
-        return 1;   /* bad signature */
-
-
-    /* could pass pointers to user-defined error handlers instead of NULLs: */
-
-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-    if (!png_ptr)
-        return 4;   /* out of memory */
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr) {
-        png_destroy_read_struct(&png_ptr, NULL, NULL);
-        return 4;   /* out of memory */
-    }
-
-
-    /* we could create a second info struct here (end_info), but it's only
-     * useful if we want to keep pre- and post-IDAT chunk info separated
-     * (mainly for PNG-aware image editors and converters) */
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return 2;
-    }
-
-
-    png_init_io(png_ptr, infile);
-    png_set_sig_bytes(png_ptr, 8);  /* we already read the 8 signature bytes */
-
-    png_read_info(png_ptr, info_ptr);  /* read all PNG info up to image data */
-
-
-    /* alternatively, could make separate calls to png_get_image_width(),
-     * etc., but want bit_depth and color_type for later [don't care about
-     * compression_type and filter_type => NULLs] */
-
-    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
-      NULL, NULL, NULL);
-    *pWidth = width;
-    *pHeight = height;
-
-
-    /* OK, that's all we need for now; return happy */
-
-    return 0;
-}
-
-
-
-
-/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
- * scales values to 8-bit if necessary */
-
-int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
-{
-    png_color_16p pBackground;
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return 2;
-    }
-
-
-    if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
-        return 1;
-
-    /* it is not obvious from the libpng documentation, but this function
-     * takes a pointer to a pointer, and it always returns valid red, green
-     * and blue values, regardless of color_type: */
-
-    png_get_bKGD(png_ptr, info_ptr, &pBackground);
-
-
-    /* however, it always returns the raw bKGD data, regardless of any
-     * bit-depth transformations, so check depth and adjust if necessary */
-
-    if (bit_depth == 16) {
-        *red   = pBackground->red   >> 8;
-        *green = pBackground->green >> 8;
-        *blue  = pBackground->blue  >> 8;
-    } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
-        if (bit_depth == 1)
-            *red = *green = *blue = pBackground->gray? 255 : 0;
-        else if (bit_depth == 2)
-            *red = *green = *blue = (255/3) * pBackground->gray;
-        else /* bit_depth == 4 */
-            *red = *green = *blue = (255/15) * pBackground->gray;
-    } else {
-        *red   = (uch)pBackground->red;
-        *green = (uch)pBackground->green;
-        *blue  = (uch)pBackground->blue;
-    }
-
-    return 0;
-}
-
-
-
-
-/* display_exponent == LUT_exponent * CRT_exponent */
-
-uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
-{
-    double  gamma;
-    png_uint_32  i, rowbytes;
-    png_bytepp  row_pointers = NULL;
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return NULL;
-    }
-
-
-    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
-     * transparency chunks to full alpha channel; strip 16-bit-per-sample
-     * images to 8 bits per sample; and convert grayscale to RGB[A] */
-
-    if (color_type == PNG_COLOR_TYPE_PALETTE)
-        png_set_expand(png_ptr);
-    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
-        png_set_expand(png_ptr);
-    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
-        png_set_expand(png_ptr);
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-    if (bit_depth == 16)
-#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-        png_set_scale_16(png_ptr);
-#  else
-        png_set_strip_16(png_ptr);
-#  endif
-#endif
-    if (color_type == PNG_COLOR_TYPE_GRAY ||
-        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-        png_set_gray_to_rgb(png_ptr);
-
-
-    /* unlike the example in the libpng documentation, we have *no* idea where
-     * this file may have come from--so if it doesn't have a file gamma, don't
-     * do any correction ("do no harm") */
-
-    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
-        png_set_gamma(png_ptr, display_exponent, gamma);
-
-
-    /* all transformations have been registered; now update info_ptr data,
-     * get rowbytes and channels, and allocate image memory */
-
-    png_read_update_info(png_ptr, info_ptr);
-
-    *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr);
-    *pChannels = (int)png_get_channels(png_ptr, info_ptr);
-
-    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return NULL;
-    }
-    if ((row_pointers = (png_bytepp)malloc(height*sizeof(png_bytep))) == NULL) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        free(image_data);
-        image_data = NULL;
-        return NULL;
-    }
-
-    Trace((stderr, "readpng_get_image:  channels = %d, rowbytes = %ld, height = %ld\n",
-        *pChannels, rowbytes, height));
-
-
-    /* set the individual row_pointers to point at the correct offsets */
-
-    for (i = 0;  i < height;  ++i)
-        row_pointers[i] = image_data + i*rowbytes;
-
-
-    /* now we can go ahead and just read the whole image */
-
-    png_read_image(png_ptr, row_pointers);
-
-
-    /* and we're done!  (png_read_end() can be omitted if no processing of
-     * post-IDAT text/time/etc. is desired) */
-
-    free(row_pointers);
-    row_pointers = NULL;
-
-    png_read_end(png_ptr, NULL);
-
-    return image_data;
-}
-
-
-void readpng_cleanup(int free_image_data)
-{
-    if (free_image_data && image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-
-    if (png_ptr && info_ptr) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        png_ptr = NULL;
-        info_ptr = NULL;
-    }
-}
diff --git a/extern/libpng/include/contrib/gregbook/readpng.h b/extern/libpng/include/contrib/gregbook/readpng.h
deleted file mode 100644
index fad9fe3b4c..0000000000
--- a/extern/libpng/include/contrib/gregbook/readpng.h
+++ /dev/null
@@ -1,88 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                              readpng.h
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#ifndef TRUE
-#  define TRUE 1
-#  define FALSE 0
-#endif
-
-#ifndef MAX
-#  define MAX(a,b)  ((a) > (b)? (a) : (b))
-#  define MIN(a,b)  ((a) < (b)? (a) : (b))
-#endif
-
-#ifdef DEBUG
-#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
-#else
-#  define Trace(x)  ;
-#endif
-
-typedef unsigned char   uch;
-typedef unsigned short  ush;
-typedef unsigned long   ulg;
-
-
-/* prototypes for public functions in readpng.c */
-
-void readpng_version_info(void);
-
-int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight);
-
-int readpng_get_bgcolor(uch *bg_red, uch *bg_green, uch *bg_blue);
-
-uch *readpng_get_image(double display_exponent, int *pChannels,
-                       ulg *pRowbytes);
-
-void readpng_cleanup(int free_image_data);
diff --git a/extern/libpng/include/contrib/gregbook/readpng2.c b/extern/libpng/include/contrib/gregbook/readpng2.c
deleted file mode 100644
index b9746b7560..0000000000
--- a/extern/libpng/include/contrib/gregbook/readpng2.c
+++ /dev/null
@@ -1,511 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                 readpng2.c
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-
-#include <stdlib.h>     /* for exit() prototype */
-#include <setjmp.h>
-
-#include <zlib.h>
-#include "png.h"        /* libpng header from the local directory */
-#include "readpng2.h"   /* typedefs, common macros, public prototypes */
-
-
-/* local prototypes */
-
-static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr);
-static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
-                                 png_uint_32 row_num, int pass);
-static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr);
-static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg);
-
-
-
-
-void readpng2_version_info(void)
-{
-    fprintf(stderr, "   Compiled with libpng %s; using libpng %s\n",
-      PNG_LIBPNG_VER_STRING, png_libpng_ver);
-
-    fprintf(stderr, "   and with zlib %s; using zlib %s.\n",
-      ZLIB_VERSION, zlib_version);
-}
-
-
-
-
-int readpng2_check_sig(uch *sig, int num)
-{
-    return !png_sig_cmp(sig, 0, num);
-}
-
-
-
-
-/* returns 0 for success, 2 for libpng problem, 4 for out of memory */
-
-int readpng2_init(mainprog_info *mainprog_ptr)
-{
-    png_structp  png_ptr;       /* note:  temporary variables! */
-    png_infop  info_ptr;
-
-
-    /* could also replace libpng warning-handler (final NULL), but no need: */
-
-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
-      readpng2_error_handler, NULL);
-    if (!png_ptr)
-        return 4;   /* out of memory */
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr) {
-        png_destroy_read_struct(&png_ptr, NULL, NULL);
-        return 4;   /* out of memory */
-    }
-
-
-    /* we could create a second info struct here (end_info), but it's only
-     * useful if we want to keep pre- and post-IDAT chunk info separated
-     * (mainly for PNG-aware image editors and converters) */
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function, unless an alternate error handler was installed--
-     * but compatible error handlers must either use longjmp() themselves
-     * (as in this program) or exit immediately, so here we are: */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return 2;
-    }
-
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-    /* prepare the reader to ignore all recognized chunks whose data won't be
-     * used, i.e., all chunks recognized by libpng except for IHDR, PLTE, IDAT,
-     * IEND, tRNS, bKGD, gAMA, and sRGB (small performance improvement) */
-    {
-        /* These byte strings were copied from png.h.  If a future libpng
-         * version recognizes more chunks, add them to this list.  If a
-         * future version of readpng2.c recognizes more chunks, delete them
-         * from this list. */
-        static /* const */ png_byte chunks_to_ignore[] = {
-             99,  72,  82,  77, '\0',  /* cHRM */
-            104,  73,  83,  84, '\0',  /* hIST */
-            105,  67,  67,  80, '\0',  /* iCCP */
-            105,  84,  88, 116, '\0',  /* iTXt */
-            111,  70,  70, 115, '\0',  /* oFFs */
-            112,  67,  65,  76, '\0',  /* pCAL */
-            112,  72,  89, 115, '\0',  /* pHYs */
-            115,  66,  73,  84, '\0',  /* sBIT */
-            115,  67,  65,  76, '\0',  /* sCAL */
-            115,  80,  76,  84, '\0',  /* sPLT */
-            115,  84,  69,  82, '\0',  /* sTER */
-            116,  69,  88, 116, '\0',  /* tEXt */
-            116,  73,  77,  69, '\0',  /* tIME */
-            122,  84,  88, 116, '\0'   /* zTXt */
-        };
-
-        png_set_keep_unknown_chunks(png_ptr, 1 /* PNG_HANDLE_CHUNK_NEVER */,
-          chunks_to_ignore, sizeof(chunks_to_ignore)/5);
-    }
-#endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */
-
-
-    /* instead of doing png_init_io() here, now we set up our callback
-     * functions for progressive decoding */
-
-    png_set_progressive_read_fn(png_ptr, mainprog_ptr,
-      readpng2_info_callback, readpng2_row_callback, readpng2_end_callback);
-
-
-    /* make sure we save our pointers for use in readpng2_decode_data() */
-
-    mainprog_ptr->png_ptr = png_ptr;
-    mainprog_ptr->info_ptr = info_ptr;
-
-
-    /* and that's all there is to initialization */
-
-    return 0;
-}
-
-
-
-
-/* returns 0 for success, 2 for libpng (longjmp) problem */
-
-int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        mainprog_ptr->png_ptr = NULL;
-        mainprog_ptr->info_ptr = NULL;
-        return 2;
-    }
-
-
-    /* hand off the next chunk of input data to libpng for decoding */
-
-    png_process_data(png_ptr, info_ptr, rawbuf, length);
-
-    return 0;
-}
-
-
-
-
-static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr)
-{
-    mainprog_info  *mainprog_ptr;
-    int  color_type, bit_depth;
-    png_uint_32 width, height;
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-    double  gamma;
-#else
-    png_fixed_point gamma;
-#endif
-
-
-    /* setjmp() doesn't make sense here, because we'd either have to exit(),
-     * longjmp() ourselves, or return control to libpng, which doesn't want
-     * to see us again.  By not doing anything here, libpng will instead jump
-     * to readpng2_decode_data(), which can return an error value to the main
-     * program. */
-
-
-    /* retrieve the pointer to our special-purpose struct, using the png_ptr
-     * that libpng passed back to us (i.e., not a global this time--there's
-     * no real difference for a single image, but for a multithreaded browser
-     * decoding several PNG images at the same time, one needs to avoid mixing
-     * up different images' structs) */
-
-    mainprog_ptr = png_get_progressive_ptr(png_ptr);
-
-    if (mainprog_ptr == NULL) {         /* we be hosed */
-        fprintf(stderr,
-          "readpng2 error:  main struct not recoverable in info_callback.\n");
-        fflush(stderr);
-        return;
-        /*
-         * Alternatively, we could call our error-handler just like libpng
-         * does, which would effectively terminate the program.  Since this
-         * can only happen if png_ptr gets redirected somewhere odd or the
-         * main PNG struct gets wiped, we're probably toast anyway.  (If
-         * png_ptr itself is NULL, we would not have been called.)
-         */
-    }
-
-
-    /* this is just like in the non-progressive case */
-
-    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
-       NULL, NULL, NULL);
-    mainprog_ptr->width = (ulg)width;
-    mainprog_ptr->height = (ulg)height;
-
-
-    /* since we know we've read all of the PNG file's "header" (i.e., up
-     * to IDAT), we can check for a background color here */
-
-    if (mainprog_ptr->need_bgcolor &&
-        png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
-    {
-        png_color_16p pBackground;
-
-        /* it is not obvious from the libpng documentation, but this function
-         * takes a pointer to a pointer, and it always returns valid red,
-         * green and blue values, regardless of color_type: */
-        png_get_bKGD(png_ptr, info_ptr, &pBackground);
-
-        /* however, it always returns the raw bKGD data, regardless of any
-         * bit-depth transformations, so check depth and adjust if necessary */
-        if (bit_depth == 16) {
-            mainprog_ptr->bg_red   = pBackground->red   >> 8;
-            mainprog_ptr->bg_green = pBackground->green >> 8;
-            mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
-        } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
-            if (bit_depth == 1)
-                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-                  mainprog_ptr->bg_blue = pBackground->gray? 255 : 0;
-            else if (bit_depth == 2)
-                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-                  mainprog_ptr->bg_blue = (255/3) * pBackground->gray;
-            else /* bit_depth == 4 */
-                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-                  mainprog_ptr->bg_blue = (255/15) * pBackground->gray;
-        } else {
-            mainprog_ptr->bg_red   = (uch)pBackground->red;
-            mainprog_ptr->bg_green = (uch)pBackground->green;
-            mainprog_ptr->bg_blue  = (uch)pBackground->blue;
-        }
-    }
-
-
-    /* as before, let libpng expand palette images to RGB, low-bit-depth
-     * grayscale images to 8 bits, transparency chunks to full alpha channel;
-     * strip 16-bit-per-sample images to 8 bits per sample; and convert
-     * grayscale to RGB[A] */
-
-    if (color_type == PNG_COLOR_TYPE_PALETTE)
-        png_set_expand(png_ptr);
-    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
-        png_set_expand(png_ptr);
-    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
-        png_set_expand(png_ptr);
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-    if (bit_depth == 16)
-#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-        png_set_scale_16(png_ptr);
-#  else
-        png_set_strip_16(png_ptr);
-#  endif
-#endif
-    if (color_type == PNG_COLOR_TYPE_GRAY ||
-        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-        png_set_gray_to_rgb(png_ptr);
-
-
-    /* Unlike the basic viewer, which was designed to operate on local files,
-     * this program is intended to simulate a web browser--even though we
-     * actually read from a local file, too.  But because we are pretending
-     * that most of the images originate on the Internet, we follow the recom-
-     * mendation of the sRGB proposal and treat unlabelled images (no gAMA
-     * chunk) as existing in the sRGB color space.  That is, we assume that
-     * such images have a file gamma of 0.45455, which corresponds to a PC-like
-     * display system.  This change in assumptions will have no effect on a
-     * PC-like system, but on a Mac, SGI, NeXT or other system with a non-
-     * identity lookup table, it will darken unlabelled images, which effec-
-     * tively favors images from PC-like systems over those originating on
-     * the local platform.  Note that mainprog_ptr->display_exponent is the
-     * "gamma" value for the entire display system, i.e., the product of
-     * LUT_exponent and CRT_exponent. */
-
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
-        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, gamma);
-    else
-        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, 0.45455);
-#else
-    if (png_get_gAMA_fixed(png_ptr, info_ptr, &gamma))
-        png_set_gamma_fixed(png_ptr,
-            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), gamma);
-    else
-        png_set_gamma_fixed(png_ptr,
-            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), 45455);
-#endif
-
-    /* we'll let libpng expand interlaced images, too */
-
-    mainprog_ptr->passes = png_set_interlace_handling(png_ptr);
-
-
-    /* all transformations have been registered; now update info_ptr data and
-     * then get rowbytes and channels */
-
-    png_read_update_info(png_ptr, info_ptr);
-
-    mainprog_ptr->rowbytes = (int)png_get_rowbytes(png_ptr, info_ptr);
-    mainprog_ptr->channels = png_get_channels(png_ptr, info_ptr);
-
-
-    /* Call the main program to allocate memory for the image buffer and
-     * initialize windows and whatnot.  (The old-style function-pointer
-     * invocation is used for compatibility with a few supposedly ANSI
-     * compilers that nevertheless barf on "fn_ptr()"-style syntax.) */
-
-    (*mainprog_ptr->mainprog_init)();
-
-
-    /* and that takes care of initialization */
-
-    return;
-}
-
-
-
-
-
-static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
-                                  png_uint_32 row_num, int pass)
-{
-    mainprog_info  *mainprog_ptr;
-
-
-    /* first check whether the row differs from the previous pass; if not,
-     * nothing to combine or display */
-
-    if (!new_row)
-        return;
-
-
-    /* retrieve the pointer to our special-purpose struct so we can access
-     * the old rows and image-display callback function */
-
-    mainprog_ptr = png_get_progressive_ptr(png_ptr);
-
-
-    /* save the pass number for optional use by the front end */
-
-    mainprog_ptr->pass = pass;
-
-
-    /* have libpng either combine the new row data with the existing row data
-     * from previous passes (if interlaced) or else just copy the new row
-     * into the main program's image buffer */
-
-    png_progressive_combine_row(png_ptr, mainprog_ptr->row_pointers[row_num],
-      new_row);
-
-
-    /* finally, call the display routine in the main program with the number
-     * of the row we just updated */
-
-    (*mainprog_ptr->mainprog_display_row)(row_num);
-
-
-    /* and we're ready for more */
-
-    return;
-}
-
-
-
-
-
-static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)
-{
-    mainprog_info  *mainprog_ptr;
-
-
-    /* retrieve the pointer to our special-purpose struct */
-
-    mainprog_ptr = png_get_progressive_ptr(png_ptr);
-
-
-    /* let the main program know that it should flush any buffered image
-     * data to the display now and set a "done" flag or whatever, but note
-     * that it SHOULD NOT DESTROY THE PNG STRUCTS YET--in other words, do
-     * NOT call readpng2_cleanup() either here or in the finish_display()
-     * routine; wait until control returns to the main program via
-     * readpng2_decode_data() */
-
-    (*mainprog_ptr->mainprog_finish_display)();
-
-
-    /* all done */
-
-    return;
-}
-
-
-
-
-
-void readpng2_cleanup(mainprog_info *mainprog_ptr)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-    if (png_ptr && info_ptr)
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-
-    mainprog_ptr->png_ptr = NULL;
-    mainprog_ptr->info_ptr = NULL;
-}
-
-
-
-
-
-static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg)
-{
-    mainprog_info  *mainprog_ptr;
-
-    /* This function, aside from the extra step of retrieving the "error
-     * pointer" (below) and the fact that it exists within the application
-     * rather than within libpng, is essentially identical to libpng's
-     * default error handler.  The second point is critical:  since both
-     * setjmp() and longjmp() are called from the same code, they are
-     * guaranteed to have compatible notions of how big a jmp_buf is,
-     * regardless of whether _BSD_SOURCE or anything else has (or has not)
-     * been defined. */
-
-    fprintf(stderr, "readpng2 libpng error: %s\n", msg);
-    fflush(stderr);
-
-    mainprog_ptr = png_get_error_ptr(png_ptr);
-    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
-        fprintf(stderr,
-          "readpng2 severe error:  jmpbuf not recoverable; terminating.\n");
-        fflush(stderr);
-        exit(99);
-    }
-
-    /* Now we have our data structure we can use the information in it
-     * to return control to our own higher level code (all the points
-     * where 'setjmp' is called in this file.)  This will work with other
-     * error handling mechanisms as well - libpng always calls png_error
-     * when it can proceed no further, thus, so long as the error handler
-     * is intercepted, application code can do its own error recovery.
-     */
-    longjmp(mainprog_ptr->jmpbuf, 1);
-}
diff --git a/extern/libpng/include/contrib/gregbook/readpng2.h b/extern/libpng/include/contrib/gregbook/readpng2.h
deleted file mode 100644
index 6b3660d7c1..0000000000
--- a/extern/libpng/include/contrib/gregbook/readpng2.h
+++ /dev/null
@@ -1,116 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                 readpng2.h
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#ifndef TRUE
-#  define TRUE 1
-#  define FALSE 0
-#endif
-
-#ifndef MAX
-#  define MAX(a,b)  ((a) > (b)? (a) : (b))
-#  define MIN(a,b)  ((a) < (b)? (a) : (b))
-#endif
-
-#ifdef DEBUG
-#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
-#else
-#  define Trace(x)  ;
-#endif
-
-enum rpng2_states {
-    kPreInit = 0,
-    kWindowInit,
-    kDone
-};
-
-typedef unsigned char   uch;
-typedef unsigned short  ush;
-typedef unsigned long   ulg;
-
-typedef struct _mainprog_info {
-    double display_exponent;
-    ulg width;
-    ulg height;
-    void *png_ptr;
-    void *info_ptr;
-    void (*mainprog_init)(void);
-    void (*mainprog_display_row)(ulg row_num);
-    void (*mainprog_finish_display)(void);
-    uch *image_data;
-    uch **row_pointers;
-    jmp_buf jmpbuf;
-    int passes;              /* not used */
-    int pass;
-    int rowbytes;
-    int channels;
-    int need_bgcolor;
-    int state;
-    uch bg_red;
-    uch bg_green;
-    uch bg_blue;
-} mainprog_info;
-
-
-/* prototypes for public functions in readpng2.c */
-
-void readpng2_version_info(void);
-
-int readpng2_check_sig(uch *sig, int num);
-
-int readpng2_init(mainprog_info *mainprog_ptr);
-
-int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length);
-
-void readpng2_cleanup(mainprog_info *mainprog_ptr);
diff --git a/extern/libpng/include/contrib/gregbook/readppm.c b/extern/libpng/include/contrib/gregbook/readppm.c
deleted file mode 100644
index be9a56d95f..0000000000
--- a/extern/libpng/include/contrib/gregbook/readppm.c
+++ /dev/null
@@ -1,179 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                              readppm.c
-
-  ---------------------------------------------------------------------------
-
-   This is a special-purpose replacement for readpng.c that allows binary
-   PPM files to be used in place of PNG images.
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "readpng.h"    /* typedefs, common macros, public prototypes */
-
-
-ulg  width, height;
-int  bit_depth, color_type, channels;
-uch  *image_data = NULL;
-FILE *saved_infile;
-
-
-void readpng_version_info()
-{
-    fprintf(stderr, "   Compiled without libpng, zlib or PBMPLUS/NetPBM.\n");
-}
-
-
-/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
-
-int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
-{
-    static uch ppmline[256];
-    int maxval;
-
-
-    saved_infile = infile;
-
-    fgets(ppmline, 256, infile);
-    if (ppmline[0] != 'P' || ppmline[1] != '6') {
-        fprintf(stderr, "ERROR:  not a PPM file\n");
-        return 1;
-    }
-    /* possible color types:  P5 = grayscale (0), P6 = RGB (2), P8 = RGBA (6) */
-    if (ppmline[1] == '6') {
-        color_type = 2;
-        channels = 3;
-    } else if (ppmline[1] == '8') {
-        color_type = 6;
-        channels = 4;
-    } else /* if (ppmline[1] == '5') */ {
-        color_type = 0;
-        channels = 1;
-    }
-
-    do {
-        fgets(ppmline, 256, infile);
-    } while (ppmline[0] == '#');
-    sscanf(ppmline, "%lu %lu", &width, &height);
-
-    do {
-        fgets(ppmline, 256, infile);
-    } while (ppmline[0] == '#');
-    sscanf(ppmline, "%d", &maxval);
-    if (maxval != 255) {
-        fprintf(stderr, "ERROR:  maxval = %d\n", maxval);
-        return 2;
-    }
-    bit_depth = 8;
-
-    *pWidth = width;
-    *pHeight = height;
-
-    return 0;
-}
-
-
-
-
-/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
- * scales values to 8-bit if necessary */
-
-int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
-{
-    return 1;
-}
-
-
-
-
-/* display_exponent == LUT_exponent * CRT_exponent */
-
-uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
-{
-    ulg  rowbytes;
-
-
-    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
-     * transparency chunks to full alpha channel; strip 16-bit-per-sample
-     * images to 8 bits per sample; and convert grayscale to RGB[A] */
-
-    /* GRR WARNING:  grayscale needs to be expanded and channels reset! */
-
-    *pRowbytes = rowbytes = channels*width;
-    *pChannels = channels;
-
-    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
-        return NULL;
-    }
-
-    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
-
-
-    /* now we can go ahead and just read the whole image */
-
-    fread(image_data, 1L, rowbytes*height, saved_infile);
-
-
-    return image_data;
-}
-
-
-void readpng_cleanup(int free_image_data)
-{
-    if (free_image_data && image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-}
diff --git a/extern/libpng/include/contrib/gregbook/rpng-win.c b/extern/libpng/include/contrib/gregbook/rpng-win.c
deleted file mode 100644
index f53ddc8ece..0000000000
--- a/extern/libpng/include/contrib/gregbook/rpng-win.c
+++ /dev/null
@@ -1,728 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                             rpng-win.c
-
-   This program decodes and displays PNG images, with gamma correction and
-   optionally with a user-specified background color (in case the image has
-   transparency).  It is very nearly the most basic PNG viewer possible.
-   This version is for 32-bit Windows; it may compile under 16-bit Windows
-   with a little tweaking (or maybe not).
-
-   to do:
-    - handle quoted command-line args (especially filenames with spaces)
-    - have minimum window width:  oh well
-    - use %.1023s to simplify truncation of title-bar string?
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.00:  initial public release
-    - 1.01:  modified to allow abbreviated options; fixed long/ulong mis-
-              match; switched to png_jmpbuf() macro
-    - 1.02:  added extra set of parentheses to png_jmpbuf() macro; fixed
-              command-line parsing bug
-    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed improper display of usage screen on PNG error(s)
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng-win"
-#define LONGNAME  "Simple PNG Viewer for Windows"
-#define VERSION   "2.01 of 16 March 2008"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-#include <windows.h>
-#ifdef __CYGWIN__
-/* getch replacement. Turns out, we don't really need this,
- * but leave it here if we ever enable any of the uses of
- * _getch in the main code
- */
-#include <unistd.h>
-#include <termio.h>
-#include <sys/ioctl.h>
-int repl_getch( void )
-{
-  char ch;
-  int fd = fileno(stdin);
-  struct termio old_tty, new_tty;
-
-  ioctl(fd, TCGETA, &old_tty);
-  new_tty = old_tty;
-  new_tty.c_lflag &= ~(ICANON | ECHO | ISIG);
-  ioctl(fd, TCSETA, &new_tty);
-  fread(&ch, 1, sizeof(ch), stdin);
-  ioctl(fd, TCSETA, &old_tty);
-
-  return ch;
-}
-#define _getch repl_getch
-#else
-#include <conio.h>      /* only for _getch() */
-#endif
-
-/* #define DEBUG  :  this enables the Trace() macros */
-
-#include "readpng.h"    /* typedefs, common macros, readpng prototypes */
-
-
-/* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
-
-#define alpha_composite(composite, fg, alpha, bg) {               \
-    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
-                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
-    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
-}
-
-
-/* local prototypes */
-static int        rpng_win_create_window(HINSTANCE hInst, int showmode);
-static int        rpng_win_display_image(void);
-static void       rpng_win_cleanup(void);
-LRESULT CALLBACK  rpng_win_wndproc(HWND, UINT, WPARAM, LPARAM);
-
-
-static char titlebar[1024];
-static char *progname = PROGNAME;
-static char *appname = LONGNAME;
-static char *filename;
-static FILE *infile;
-
-static char *bgstr;
-static uch bg_red=0, bg_green=0, bg_blue=0;
-
-static double display_exponent;
-
-static ulg image_width, image_height, image_rowbytes;
-static int image_channels;
-static uch *image_data;
-
-/* Windows-specific variables */
-static ulg wimage_rowbytes;
-static uch *dib;
-static uch *wimage_data;
-static BITMAPINFOHEADER *bmih;
-
-static HWND global_hwnd;
-
-
-
-
-int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
-{
-    char *args[1024];                 /* arbitrary limit, but should suffice */
-    char *p, *q, **argv = args;
-    int argc = 0;
-    int rc, alen, flen;
-    int error = 0;
-    int have_bg = FALSE;
-    double LUT_exponent;              /* just the lookup table */
-    double CRT_exponent = 2.2;        /* just the monitor */
-    double default_display_exponent;  /* whole display system */
-    MSG msg;
-
-
-    filename = (char *)NULL;
-
-#ifndef __CYGWIN__
-    /* First reenable console output, which normally goes to the bit bucket
-     * for windowed apps.  Closing the console window will terminate the
-     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
-     * incantation. */
-
-    AllocConsole();
-    freopen("CONOUT$", "a", stderr);
-    freopen("CONOUT$", "a", stdout);
-#endif
-
-
-    /* Next set the default value for our display-system exponent, i.e.,
-     * the product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  This is not an
-     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
-     * ones), but it should cover 99% of the current possibilities.  And
-     * yes, these ifdefs are completely wasted in a Windows program... */
-
-#if defined(NeXT)
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to get the
-     * "gamma" value, so we do it the hard way */
-    infile = fopen("/etc/config/system.glGammaVal", "r");
-    if (infile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, infile);
-        fclose(infile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL)
-        display_exponent = atof(p);
-    else
-        display_exponent = default_display_exponent;
-
-
-    /* Windows really hates command lines, so we have to set up our own argv.
-     * Note that we do NOT bother with quoted arguments here, so don't use
-     * filenames with spaces in 'em! */
-
-    argv[argc++] = PROGNAME;
-    p = cmd;
-    for (;;) {
-        if (*p == ' ')
-            while (*++p == ' ')
-                ;
-        /* now p points at the first non-space after some spaces */
-        if (*p == '\0')
-            break;    /* nothing after the spaces:  done */
-        argv[argc++] = q = p;
-        while (*q && *q != ' ')
-            ++q;
-        /* now q points at a space or the end of the string */
-        if (*q == '\0')
-            break;    /* last argv already terminated; quit */
-        *q = '\0';    /* change space to terminator */
-        p = q + 1;
-    }
-    argv[argc] = NULL;   /* terminate the argv array itself */
-
-
-    /* Now parse the command line for options and the PNG filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                display_exponent = atof(*argv);
-                if (display_exponent <= 0.0)
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else
-                    have_bg = TRUE;
-            }
-        } else {
-            if (**argv != '-') {
-                filename = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-    if (!filename)
-        ++error;
-
-
-    /* print usage screen if any errors up to this point */
-
-    if (error) {
-#ifndef __CYGWIN__
-        int ch;
-#endif
-
-        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
-        readpng_version_info();
-        fprintf(stderr, "\n"
-          "Usage:  %s [-gamma exp] [-bgcolor bg] file.png\n"
-          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
-          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
-          "    bg  \tdesired background color in 7-character hex RGB format\n"
-          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
-          "\t\t  used with transparent images\n"
-          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
-#ifndef __CYGWIN__
-          "Press Q or Esc to quit this usage screen.\n"
-#endif
-          "\n", PROGNAME, default_display_exponent);
-#ifndef __CYGWIN__
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-#endif
-        exit(1);
-    }
-
-
-    if (!(infile = fopen(filename, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
-        ++error;
-    } else {
-        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
-            switch (rc) {
-                case 1:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] is not a PNG file: incorrect signature\n",
-                      filename);
-                    break;
-                case 2:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
-                    break;
-                case 4:
-                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                    break;
-                default:
-                    fprintf(stderr, PROGNAME
-                      ":  unknown readpng_init() error\n");
-                    break;
-            }
-            ++error;
-        }
-        if (error)
-            fclose(infile);
-    }
-
-
-    if (error) {
-#ifndef __CYGWIN__
-        int ch;
-#endif
-
-        fprintf(stderr, PROGNAME ":  aborting.\n");
-#ifndef __CYGWIN__
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-#endif
-        exit(2);
-    } else {
-        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
-#ifndef __CYGWIN__
-        fprintf(stderr,
-          "\n   [console window:  closing this window will terminate %s]\n\n",
-          PROGNAME);
-#endif
-    }
-
-
-    /* set the title-bar string, but make sure buffer doesn't overflow */
-
-    alen = strlen(appname);
-    flen = strlen(filename);
-    if (alen + flen + 3 > 1023)
-        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
-    else
-        sprintf(titlebar, "%s:  %s", appname, filename);
-
-
-    /* if the user didn't specify a background color on the command line,
-     * check for one in the PNG file--if not, the initialized values of 0
-     * (black) will be used */
-
-    if (have_bg) {
-        unsigned r, g, b;   /* this approach quiets compiler warnings */
-
-        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-        bg_red   = (uch)r;
-        bg_green = (uch)g;
-        bg_blue  = (uch)b;
-    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
-        readpng_cleanup(TRUE);
-        fprintf(stderr, PROGNAME
-          ":  libpng error while checking for background color\n");
-        exit(2);
-    }
-
-
-    /* do the basic Windows initialization stuff, make the window and fill it
-     * with the background color */
-
-    if (rpng_win_create_window(hInst, showmode))
-        exit(2);
-
-
-    /* decode the image, all at once */
-
-    Trace((stderr, "calling readpng_get_image()\n"))
-    image_data = readpng_get_image(display_exponent, &image_channels,
-      &image_rowbytes);
-    Trace((stderr, "done with readpng_get_image()\n"))
-
-
-    /* done with PNG file, so clean up to minimize memory usage (but do NOT
-     * nuke image_data!) */
-
-    readpng_cleanup(FALSE);
-    fclose(infile);
-
-    if (!image_data) {
-        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
-        exit(3);
-    }
-
-
-    /* display image (composite with background if requested) */
-
-    Trace((stderr, "calling rpng_win_display_image()\n"))
-    if (rpng_win_display_image()) {
-        free(image_data);
-        exit(4);
-    }
-    Trace((stderr, "done with rpng_win_display_image()\n"))
-
-
-    /* wait for the user to tell us when to quit */
-
-    printf(
-#ifndef __CYGWIN__
-      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n"
-#else
-      "Done.  Press mouse button 1 (within image window) to quit.\n"
-#endif
-    );
-    fflush(stdout);
-
-    while (GetMessage(&msg, NULL, 0, 0)) {
-        TranslateMessage(&msg);
-        DispatchMessage(&msg);
-    }
-
-
-    /* OK, we're done:  clean up all image and Windows resources and go away */
-
-    rpng_win_cleanup();
-
-    return msg.wParam;
-}
-
-
-
-
-
-static int rpng_win_create_window(HINSTANCE hInst, int showmode)
-{
-    uch *dest;
-    int extra_width, extra_height;
-    ulg i, j;
-    WNDCLASSEX wndclass;
-
-
-/*---------------------------------------------------------------------------
-    Allocate memory for the display-specific version of the image (round up
-    to multiple of 4 for Windows DIB).
-  ---------------------------------------------------------------------------*/
-
-    wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;
-
-    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
-                              wimage_rowbytes*image_height)))
-    {
-        return 4;   /* fail */
-    }
-
-/*---------------------------------------------------------------------------
-    Initialize the DIB.  Negative height means to use top-down BMP ordering
-    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
-    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
-    directly => wimage_data begins immediately after BMP header.
-  ---------------------------------------------------------------------------*/
-
-    memset(dib, 0, sizeof(BITMAPINFOHEADER));
-    bmih = (BITMAPINFOHEADER *)dib;
-    bmih->biSize = sizeof(BITMAPINFOHEADER);
-    bmih->biWidth = image_width;
-    bmih->biHeight = -((long)image_height);
-    bmih->biPlanes = 1;
-    bmih->biBitCount = 24;
-    bmih->biCompression = 0;
-    wimage_data = dib + sizeof(BITMAPINFOHEADER);
-
-/*---------------------------------------------------------------------------
-    Fill in background color (black by default); data are in BGR order.
-  ---------------------------------------------------------------------------*/
-
-    for (j = 0;  j < image_height;  ++j) {
-        dest = wimage_data + j*wimage_rowbytes;
-        for (i = image_width;  i > 0;  --i) {
-            *dest++ = bg_blue;
-            *dest++ = bg_green;
-            *dest++ = bg_red;
-        }
-    }
-
-/*---------------------------------------------------------------------------
-    Set the window parameters.
-  ---------------------------------------------------------------------------*/
-
-    memset(&wndclass, 0, sizeof(wndclass));
-
-    wndclass.cbSize = sizeof(wndclass);
-    wndclass.style = CS_HREDRAW | CS_VREDRAW;
-    wndclass.lpfnWndProc = rpng_win_wndproc;
-    wndclass.hInstance = hInst;
-    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
-    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
-    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
-    wndclass.lpszMenuName = NULL;
-    wndclass.lpszClassName = progname;
-    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
-
-    RegisterClassEx(&wndclass);
-
-/*---------------------------------------------------------------------------
-    Finally, create the window.
-  ---------------------------------------------------------------------------*/
-
-    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
-                      GetSystemMetrics(SM_CXDLGFRAME));
-    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
-                      GetSystemMetrics(SM_CYDLGFRAME)) +
-                      GetSystemMetrics(SM_CYCAPTION);
-
-    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
-      CW_USEDEFAULT, CW_USEDEFAULT, image_width+extra_width,
-      image_height+extra_height, NULL, NULL, hInst, NULL);
-
-    ShowWindow(global_hwnd, showmode);
-    UpdateWindow(global_hwnd);
-
-    return 0;
-
-} /* end function rpng_win_create_window() */
-
-
-
-
-
-static int rpng_win_display_image()
-{
-    uch *src, *dest;
-    uch r, g, b, a;
-    ulg i, row, lastrow;
-    RECT rect;
-
-
-    Trace((stderr, "beginning display loop (image_channels == %d)\n",
-      image_channels))
-    Trace((stderr, "(width = %ld, rowbytes = %ld, wimage_rowbytes = %d)\n",
-      image_width, image_rowbytes, wimage_rowbytes))
-
-
-/*---------------------------------------------------------------------------
-    Blast image data to buffer.  This whole routine takes place before the
-    message loop begins, so there's no real point in any pseudo-progressive
-    display...
-  ---------------------------------------------------------------------------*/
-
-    for (lastrow = row = 0;  row < image_height;  ++row) {
-        src = image_data + row*image_rowbytes;
-        dest = wimage_data + row*wimage_rowbytes;
-        if (image_channels == 3) {
-            for (i = image_width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                *dest++ = b;
-                *dest++ = g;   /* note reverse order */
-                *dest++ = r;
-            }
-        } else /* if (image_channels == 4) */ {
-            for (i = image_width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                a = *src++;
-                if (a == 255) {
-                    *dest++ = b;
-                    *dest++ = g;
-                    *dest++ = r;
-                } else if (a == 0) {
-                    *dest++ = bg_blue;
-                    *dest++ = bg_green;
-                    *dest++ = bg_red;
-                } else {
-                    /* this macro (copied from png.h) composites the
-                     * foreground and background values and puts the
-                     * result into the first argument; there are no
-                     * side effects with the first argument */
-                    alpha_composite(*dest++, b, a, bg_blue);
-                    alpha_composite(*dest++, g, a, bg_green);
-                    alpha_composite(*dest++, r, a, bg_red);
-                }
-            }
-        }
-        /* display after every 16 lines */
-        if (((row+1) & 0xf) == 0) {
-            rect.left = 0L;
-            rect.top = (LONG)lastrow;
-            rect.right = (LONG)image_width;      /* possibly off by one? */
-            rect.bottom = (LONG)lastrow + 16L;   /* possibly off by one? */
-            InvalidateRect(global_hwnd, &rect, FALSE);
-            UpdateWindow(global_hwnd);     /* similar to XFlush() */
-            lastrow = row + 1;
-        }
-    }
-
-    Trace((stderr, "calling final image-flush routine\n"))
-    if (lastrow < image_height) {
-        rect.left = 0L;
-        rect.top = (LONG)lastrow;
-        rect.right = (LONG)image_width;      /* possibly off by one? */
-        rect.bottom = (LONG)image_height;    /* possibly off by one? */
-        InvalidateRect(global_hwnd, &rect, FALSE);
-        UpdateWindow(global_hwnd);     /* similar to XFlush() */
-    }
-
-/*
-    last param determines whether or not background is wiped before paint
-    InvalidateRect(global_hwnd, NULL, TRUE);
-    UpdateWindow(global_hwnd);
- */
-
-    return 0;
-}
-
-
-
-
-
-static void rpng_win_cleanup()
-{
-    if (image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-
-    if (dib) {
-        free(dib);
-        dib = NULL;
-    }
-}
-
-
-
-
-
-LRESULT CALLBACK rpng_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
-{
-    HDC         hdc;
-    PAINTSTRUCT ps;
-    int rc;
-
-    switch (iMsg) {
-        case WM_CREATE:
-            /* one-time processing here, if any */
-            return 0;
-
-        case WM_PAINT:
-            hdc = BeginPaint(hwnd, &ps);
-                    /*                    dest                          */
-            rc = StretchDIBits(hdc, 0, 0, image_width, image_height,
-                    /*                    source                        */
-                                    0, 0, image_width, image_height,
-                                    wimage_data, (BITMAPINFO *)bmih,
-                    /*              iUsage: no clue                     */
-                                    0, SRCCOPY);
-            EndPaint(hwnd, &ps);
-            return 0;
-
-        /* wait for the user to tell us when to quit */
-        case WM_CHAR:
-            switch (wP) {      /* only need one, so ignore repeat count */
-                case 'q':
-                case 'Q':
-                case 0x1B:     /* Esc key */
-                    PostQuitMessage(0);
-            }
-            return 0;
-
-        case WM_LBUTTONDOWN:   /* another way of quitting */
-        case WM_DESTROY:
-            PostQuitMessage(0);
-            return 0;
-    }
-
-    return DefWindowProc(hwnd, iMsg, wP, lP);
-}
diff --git a/extern/libpng/include/contrib/gregbook/rpng-x.c b/extern/libpng/include/contrib/gregbook/rpng-x.c
deleted file mode 100644
index 6d10e1b84e..0000000000
--- a/extern/libpng/include/contrib/gregbook/rpng-x.c
+++ /dev/null
@@ -1,904 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                               rpng-x.c
-
-   This program decodes and displays PNG images, with gamma correction and
-   optionally with a user-specified background color (in case the image has
-   transparency).  It is very nearly the most basic PNG viewer possible.
-   This version is for the X Window System (tested by author under Unix and
-   by Martin Zinser under OpenVMS; may work under OS/2 with some tweaking).
-
-   to do:
-    - 8-bit (colormapped) X support
-    - use %.1023s to simplify truncation of title-bar string?
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.01:  initial public release
-    - 1.02:  modified to allow abbreviated options; fixed long/ulong mis-
-              match; switched to png_jmpbuf() macro
-    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
-    - 1.11:  added extra set of parentheses to png_jmpbuf() macro; fixed
-              command-line parsing bug
-    - 1.12:  fixed some small X memory leaks (thanks to Fran�ois Petitjean)
-    - 1.13:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
-    - 1.14:  added support for X resources (thanks to Gerhard Niklasch)
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed improper display of usage screen on PNG error(s)
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng-x"
-#define LONGNAME  "Simple PNG Viewer for X"
-#define VERSION   "2.01 of 16 March 2008"
-#define RESNAME   "rpng"        /* our X resource application name */
-#define RESCLASS  "Rpng"        /* our X resource class name */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-#include <X11/Xlib.h>
-#include <X11/Xutil.h>
-#include <X11/Xos.h>
-#include <X11/keysym.h>
-
-/* #define DEBUG  :  this enables the Trace() macros */
-
-#include "readpng.h"   /* typedefs, common macros, readpng prototypes */
-
-
-/* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
-
-#define alpha_composite(composite, fg, alpha, bg) {               \
-    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
-                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
-    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
-}
-
-
-/* local prototypes */
-static int  rpng_x_create_window(void);
-static int  rpng_x_display_image(void);
-static void rpng_x_cleanup(void);
-static int  rpng_x_msb(ulg u32val);
-
-
-static char titlebar[1024], *window_name = titlebar;
-static char *appname = LONGNAME;
-static char *icon_name = PROGNAME;
-static char *res_name = RESNAME;
-static char *res_class = RESCLASS;
-static char *filename;
-static FILE *infile;
-
-static char *bgstr;
-static uch bg_red=0, bg_green=0, bg_blue=0;
-
-static double display_exponent;
-
-static ulg image_width, image_height, image_rowbytes;
-static int image_channels;
-static uch *image_data;
-
-/* X-specific variables */
-static char *displayname;
-static XImage *ximage;
-static Display *display;
-static int depth;
-static Visual *visual;
-static XVisualInfo *visual_list;
-static int RShift, GShift, BShift;
-static ulg RMask, GMask, BMask;
-static Window window;
-static GC gc;
-static Colormap colormap;
-
-static int have_nondefault_visual = FALSE;
-static int have_colormap = FALSE;
-static int have_window = FALSE;
-static int have_gc = FALSE;
-/*
-ulg numcolors=0, pixels[256];
-ush reds[256], greens[256], blues[256];
- */
-
-
-
-
-int main(int argc, char **argv)
-{
-#ifdef sgi
-    char tmpline[80];
-#endif
-    char *p;
-    int rc, alen, flen;
-    int error = 0;
-    int have_bg = FALSE;
-    double LUT_exponent;               /* just the lookup table */
-    double CRT_exponent = 2.2;         /* just the monitor */
-    double default_display_exponent;   /* whole display system */
-    XEvent e;
-    KeySym k;
-
-
-    displayname = (char *)NULL;
-    filename = (char *)NULL;
-
-
-    /* First set the default value for our display-system exponent, i.e.,
-     * the product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  This is not an
-     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
-     * ones), but it should cover 99% of the current possibilities. */
-
-#if defined(NeXT)
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to get the
-     * "gamma" value, so we do it the hard way */
-    infile = fopen("/etc/config/system.glGammaVal", "r");
-    if (infile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, infile);
-        fclose(infile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL)
-        display_exponent = atof(p);
-    else
-        display_exponent = default_display_exponent;
-
-
-    /* Now parse the command line for options and the PNG filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-display", 2)) {
-            if (!*++argv)
-                ++error;
-            else
-                displayname = *argv;
-        } else if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                display_exponent = atof(*argv);
-                if (display_exponent <= 0.0)
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else
-                    have_bg = TRUE;
-            }
-        } else {
-            if (**argv != '-') {
-                filename = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-    if (!filename)
-        ++error;
-
-
-    /* print usage screen if any errors up to this point */
-
-    if (error) {
-        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
-        readpng_version_info();
-        fprintf(stderr, "\n"
-          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg] file.png\n"
-          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
-          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
-          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
-          "    bg  \tdesired background color in 7-character hex RGB format\n"
-          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
-          "\t\t  used with transparent images\n"
-          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
-          "\n", PROGNAME, default_display_exponent);
-        exit(1);
-    }
-
-
-    if (!(infile = fopen(filename, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
-        ++error;
-    } else {
-        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
-            switch (rc) {
-                case 1:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] is not a PNG file: incorrect signature\n",
-                      filename);
-                    break;
-                case 2:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
-                    break;
-                case 4:
-                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                    break;
-                default:
-                    fprintf(stderr, PROGNAME
-                      ":  unknown readpng_init() error\n");
-                    break;
-            }
-            ++error;
-        } else {
-            display = XOpenDisplay(displayname);
-            if (!display) {
-                readpng_cleanup(TRUE);
-                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
-                  displayname? displayname : "default");
-                ++error;
-            }
-        }
-        if (error)
-            fclose(infile);
-    }
-
-
-    if (error) {
-        fprintf(stderr, PROGNAME ":  aborting.\n");
-        exit(2);
-    }
-
-
-    /* set the title-bar string, but make sure buffer doesn't overflow */
-
-    alen = strlen(appname);
-    flen = strlen(filename);
-    if (alen + flen + 3 > 1023)
-        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
-    else
-        sprintf(titlebar, "%s:  %s", appname, filename);
-
-
-    /* if the user didn't specify a background color on the command line,
-     * check for one in the PNG file--if not, the initialized values of 0
-     * (black) will be used */
-
-    if (have_bg) {
-        unsigned r, g, b;   /* this approach quiets compiler warnings */
-
-        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-        bg_red   = (uch)r;
-        bg_green = (uch)g;
-        bg_blue  = (uch)b;
-    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
-        readpng_cleanup(TRUE);
-        fprintf(stderr, PROGNAME
-          ":  libpng error while checking for background color\n");
-        exit(2);
-    }
-
-
-    /* do the basic X initialization stuff, make the window and fill it
-     * with the background color */
-
-    if (rpng_x_create_window())
-        exit(2);
-
-
-    /* decode the image, all at once */
-
-    Trace((stderr, "calling readpng_get_image()\n"))
-    image_data = readpng_get_image(display_exponent, &image_channels,
-      &image_rowbytes);
-    Trace((stderr, "done with readpng_get_image()\n"))
-
-
-    /* done with PNG file, so clean up to minimize memory usage (but do NOT
-     * nuke image_data!) */
-
-    readpng_cleanup(FALSE);
-    fclose(infile);
-
-    if (!image_data) {
-        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
-        exit(3);
-    }
-
-
-    /* display image (composite with background if requested) */
-
-    Trace((stderr, "calling rpng_x_display_image()\n"))
-    if (rpng_x_display_image()) {
-        free(image_data);
-        exit(4);
-    }
-    Trace((stderr, "done with rpng_x_display_image()\n"))
-
-
-    /* wait for the user to tell us when to quit */
-
-    printf(
-      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
-    fflush(stdout);
-
-    do
-        XNextEvent(display, &e);
-    while (!(e.type == ButtonPress && e.xbutton.button == Button1) &&
-           !(e.type == KeyPress &&    /*  v--- or 1 for shifted keys */
-             ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape) ));
-
-
-    /* OK, we're done:  clean up all image and X resources and go away */
-
-    rpng_x_cleanup();
-
-    return 0;
-}
-
-
-
-
-
-static int rpng_x_create_window(void)
-{
-    uch *xdata;
-    int need_colormap = FALSE;
-    int screen, pad;
-    ulg bg_pixel = 0L;
-    ulg attrmask;
-    Window root;
-    XEvent e;
-    XGCValues gcvalues;
-    XSetWindowAttributes attr;
-    XTextProperty windowName, *pWindowName = &windowName;
-    XTextProperty iconName, *pIconName = &iconName;
-    XVisualInfo visual_info;
-    XSizeHints *size_hints;
-    XWMHints *wm_hints;
-    XClassHint *class_hints;
-
-
-    screen = DefaultScreen(display);
-    depth = DisplayPlanes(display, screen);
-    root = RootWindow(display, screen);
-
-#ifdef DEBUG
-    XSynchronize(display, True);
-#endif
-
-#if 0
-/* GRR:  add 8-bit support */
-    if (/* depth != 8 && */ depth != 16 && depth != 24 && depth != 32) {
-        fprintf(stderr,
-          "screen depth %d not supported (only 16-, 24- or 32-bit TrueColor)\n",
-          depth);
-        return 2;
-    }
-
-    XMatchVisualInfo(display, screen, depth,
-      (depth == 8)? PseudoColor : TrueColor, &visual_info);
-    visual = visual_info.visual;
-#else
-    if (depth != 16 && depth != 24 && depth != 32) {
-        int visuals_matched = 0;
-
-        Trace((stderr, "default depth is %d:  checking other visuals\n",
-          depth))
-
-        /* 24-bit first */
-        visual_info.screen = screen;
-        visual_info.depth = 24;
-        visual_list = XGetVisualInfo(display,
-          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
-        if (visuals_matched == 0) {
-/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
-            fprintf(stderr, "default screen depth %d not supported, and no"
-              " 24-bit visuals found\n", depth);
-            return 2;
-        }
-        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
-          visuals_matched))
-        visual = visual_list[0].visual;
-        depth = visual_list[0].depth;
-/*
-        colormap_size = visual_list[0].colormap_size;
-        visual_class = visual->class;
-        visualID = XVisualIDFromVisual(visual);
- */
-        have_nondefault_visual = TRUE;
-        need_colormap = TRUE;
-    } else {
-        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
-        visual = visual_info.visual;
-    }
-#endif
-
-    RMask = visual->red_mask;
-    GMask = visual->green_mask;
-    BMask = visual->blue_mask;
-
-/* GRR:  add/check 8-bit support */
-    if (depth == 8 || need_colormap) {
-        colormap = XCreateColormap(display, root, visual, AllocNone);
-        if (!colormap) {
-            fprintf(stderr, "XCreateColormap() failed\n");
-            return 2;
-        }
-        have_colormap = TRUE;
-    }
-    if (depth == 15 || depth == 16) {
-        RShift = 15 - rpng_x_msb(RMask);    /* these are right-shifts */
-        GShift = 15 - rpng_x_msb(GMask);
-        BShift = 15 - rpng_x_msb(BMask);
-    } else if (depth > 16) {
-#define NO_24BIT_MASKS
-#ifdef NO_24BIT_MASKS
-        RShift = rpng_x_msb(RMask) - 7;     /* these are left-shifts */
-        GShift = rpng_x_msb(GMask) - 7;
-        BShift = rpng_x_msb(BMask) - 7;
-#else
-        RShift = 7 - rpng_x_msb(RMask);     /* these are right-shifts, too */
-        GShift = 7 - rpng_x_msb(GMask);
-        BShift = 7 - rpng_x_msb(BMask);
-#endif
-    }
-    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
-        fprintf(stderr, "rpng internal logic error:  negative X shift(s)!\n");
-        return 2;
-    }
-
-/*---------------------------------------------------------------------------
-    Finally, create the window.
-  ---------------------------------------------------------------------------*/
-
-    attr.backing_store = Always;
-    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
-    attrmask = CWBackingStore | CWEventMask;
-    if (have_nondefault_visual) {
-        attr.colormap = colormap;
-        attr.background_pixel = 0;
-        attr.border_pixel = 1;
-        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
-    }
-
-    window = XCreateWindow(display, root, 0, 0, image_width, image_height, 0,
-      depth, InputOutput, visual, attrmask, &attr);
-
-    if (window == None) {
-        fprintf(stderr, "XCreateWindow() failed\n");
-        return 2;
-    } else
-        have_window = TRUE;
-
-    if (depth == 8)
-        XSetWindowColormap(display, window, colormap);
-
-    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
-        pWindowName = NULL;
-    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
-        pIconName = NULL;
-
-    /* OK if any hints allocation fails; XSetWMProperties() allows NULLs */
-
-    if ((size_hints = XAllocSizeHints()) != NULL) {
-        /* window will not be resizable */
-        size_hints->flags = PMinSize | PMaxSize;
-        size_hints->min_width = size_hints->max_width = (int)image_width;
-        size_hints->min_height = size_hints->max_height = (int)image_height;
-    }
-
-    if ((wm_hints = XAllocWMHints()) != NULL) {
-        wm_hints->initial_state = NormalState;
-        wm_hints->input = True;
-     /* wm_hints->icon_pixmap = icon_pixmap; */
-        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
-    }
-
-    if ((class_hints = XAllocClassHint()) != NULL) {
-        class_hints->res_name = res_name;
-        class_hints->res_class = res_class;
-    }
-
-    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
-      size_hints, wm_hints, class_hints);
-
-    /* various properties and hints no longer needed; free memory */
-    if (pWindowName)
-       XFree(pWindowName->value);
-    if (pIconName)
-       XFree(pIconName->value);
-    if (size_hints)
-        XFree(size_hints);
-    if (wm_hints)
-       XFree(wm_hints);
-    if (class_hints)
-       XFree(class_hints);
-
-    XMapWindow(display, window);
-
-    gc = XCreateGC(display, window, 0, &gcvalues);
-    have_gc = TRUE;
-
-/*---------------------------------------------------------------------------
-    Fill window with the specified background color.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        bg_pixel = ((ulg)bg_red   << RShift) |
-                   ((ulg)bg_green << GShift) |
-                   ((ulg)bg_blue  << BShift);
-    } else if (depth == 16) {
-        bg_pixel = ((((ulg)bg_red   << 8) >> RShift) & RMask) |
-                   ((((ulg)bg_green << 8) >> GShift) & GMask) |
-                   ((((ulg)bg_blue  << 8) >> BShift) & BMask);
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-    XSetForeground(display, gc, bg_pixel);
-    XFillRectangle(display, window, gc, 0, 0, image_width, image_height);
-
-/*---------------------------------------------------------------------------
-    Wait for first Expose event to do any drawing, then flush.
-  ---------------------------------------------------------------------------*/
-
-    do
-        XNextEvent(display, &e);
-    while (e.type != Expose || e.xexpose.count);
-
-    XFlush(display);
-
-/*---------------------------------------------------------------------------
-    Allocate memory for the X- and display-specific version of the image.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        xdata = (uch *)malloc(4*image_width*image_height);
-        pad = 32;
-    } else if (depth == 16) {
-        xdata = (uch *)malloc(2*image_width*image_height);
-        pad = 16;
-    } else /* depth == 8 */ {
-        xdata = (uch *)malloc(image_width*image_height);
-        pad = 8;
-    }
-
-    if (!xdata) {
-        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
-        return 4;
-    }
-
-    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
-      (char *)xdata, image_width, image_height, pad, 0);
-
-    if (!ximage) {
-        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
-        free(xdata);
-        return 3;
-    }
-
-    /* to avoid testing the byte order every pixel (or doubling the size of
-     * the drawing routine with a giant if-test), we arbitrarily set the byte
-     * order to MSBFirst and let Xlib worry about inverting things on little-
-     * endian machines (like Linux/x86, old VAXen, etc.)--this is not the most
-     * efficient approach (the giant if-test would be better), but in the
-     * interest of clarity, we take the easy way out... */
-
-    ximage->byte_order = MSBFirst;
-
-    return 0;
-
-} /* end function rpng_x_create_window() */
-
-
-
-
-
-static int rpng_x_display_image(void)
-{
-    uch *src;
-    char *dest;
-    uch r, g, b, a;
-    ulg i, row, lastrow = 0;
-    ulg pixel;
-    int ximage_rowbytes = ximage->bytes_per_line;
-/*  int bpp = ximage->bits_per_pixel;  */
-
-
-    Trace((stderr, "beginning display loop (image_channels == %d)\n",
-      image_channels))
-    Trace((stderr, "   (width = %ld, rowbytes = %ld, ximage_rowbytes = %d)\n",
-      image_width, image_rowbytes, ximage_rowbytes))
-    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
-    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
-      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
-
-    if (depth == 24 || depth == 32) {
-        ulg red, green, blue;
-
-        for (lastrow = row = 0;  row < image_height;  ++row) {
-            src = image_data + row*image_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (image_channels == 3) {
-                for (i = image_width;  i > 0;  --i) {
-                    red   = *src++;
-                    green = *src++;
-                    blue  = *src++;
-#ifdef NO_24BIT_MASKS
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    /* GRR BUG:  this assumes bpp == 32, but may be 24: */
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-#else
-                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
-                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
-                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
-                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-#endif
-                }
-            } else /* if (image_channels == 4) */ {
-                for (i = image_width;  i > 0;  --i) {
-                    r = *src++;
-                    g = *src++;
-                    b = *src++;
-                    a = *src++;
-                    if (a == 255) {
-                        red   = r;
-                        green = g;
-                        blue  = b;
-                    } else if (a == 0) {
-                        red   = bg_red;
-                        green = bg_green;
-                        blue  = bg_blue;
-                    } else {
-                        /* this macro (from png.h) composites the foreground
-                         * and background values and puts the result into the
-                         * first argument */
-                        alpha_composite(red,   r, a, bg_red);
-                        alpha_composite(green, g, a, bg_green);
-                        alpha_composite(blue,  b, a, bg_blue);
-                    }
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-            /* display after every 16 lines */
-            if (((row+1) & 0xf) == 0) {
-                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-                  (int)lastrow, image_width, 16);
-                XFlush(display);
-                lastrow = row + 1;
-            }
-        }
-
-    } else if (depth == 16) {
-        ush red, green, blue;
-
-        for (lastrow = row = 0;  row < image_height;  ++row) {
-            src = image_data + row*image_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (image_channels == 3) {
-                for (i = image_width;  i > 0;  --i) {
-                    red   = ((ush)(*src) << 8);
-                    ++src;
-                    green = ((ush)(*src) << 8);
-                    ++src;
-                    blue  = ((ush)(*src) << 8);
-                    ++src;
-                    pixel = ((red   >> RShift) & RMask) |
-                            ((green >> GShift) & GMask) |
-                            ((blue  >> BShift) & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            } else /* if (image_channels == 4) */ {
-                for (i = image_width;  i > 0;  --i) {
-                    r = *src++;
-                    g = *src++;
-                    b = *src++;
-                    a = *src++;
-                    if (a == 255) {
-                        red   = ((ush)r << 8);
-                        green = ((ush)g << 8);
-                        blue  = ((ush)b << 8);
-                    } else if (a == 0) {
-                        red   = ((ush)bg_red   << 8);
-                        green = ((ush)bg_green << 8);
-                        blue  = ((ush)bg_blue  << 8);
-                    } else {
-                        /* this macro (from png.h) composites the foreground
-                         * and background values and puts the result back into
-                         * the first argument (== fg byte here:  safe) */
-                        alpha_composite(r, r, a, bg_red);
-                        alpha_composite(g, g, a, bg_green);
-                        alpha_composite(b, b, a, bg_blue);
-                        red   = ((ush)r << 8);
-                        green = ((ush)g << 8);
-                        blue  = ((ush)b << 8);
-                    }
-                    pixel = ((red   >> RShift) & RMask) |
-                            ((green >> GShift) & GMask) |
-                            ((blue  >> BShift) & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-            /* display after every 16 lines */
-            if (((row+1) & 0xf) == 0) {
-                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-                  (int)lastrow, image_width, 16);
-                XFlush(display);
-                lastrow = row + 1;
-            }
-        }
-
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-    Trace((stderr, "calling final XPutImage()\n"))
-    if (lastrow < image_height) {
-        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-          (int)lastrow, image_width, image_height-lastrow);
-        XFlush(display);
-    }
-
-    return 0;
-}
-
-
-
-
-static void rpng_x_cleanup(void)
-{
-    if (image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-
-    if (ximage) {
-        if (ximage->data) {
-            free(ximage->data);           /* we allocated it, so we free it */
-            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
-        }
-        XDestroyImage(ximage);
-        ximage = NULL;
-    }
-
-    if (have_gc)
-        XFreeGC(display, gc);
-
-    if (have_window)
-        XDestroyWindow(display, window);
-
-    if (have_colormap)
-        XFreeColormap(display, colormap);
-
-    if (have_nondefault_visual)
-        XFree(visual_list);
-}
-
-
-
-
-
-static int rpng_x_msb(ulg u32val)
-{
-    int i;
-
-    for (i = 31;  i >= 0;  --i) {
-        if (u32val & 0x80000000L)
-            break;
-        u32val <<= 1;
-    }
-    return i;
-}
diff --git a/extern/libpng/include/contrib/gregbook/rpng2-win.c b/extern/libpng/include/contrib/gregbook/rpng2-win.c
deleted file mode 100644
index 223e737409..0000000000
--- a/extern/libpng/include/contrib/gregbook/rpng2-win.c
+++ /dev/null
@@ -1,1253 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                rpng2-win.c
-
-   This program decodes and displays PNG files progressively, as if it were
-   a web browser (though the front end is only set up to read from files).
-   It supports gamma correction, user-specified background colors, and user-
-   specified background patterns (for transparent images).  This version is
-   for 32-bit Windows; it may compile under 16-bit Windows with a little
-   tweaking (or maybe not).  Thanks to Adam Costello and Pieter S. van der
-   Meulen for the "diamond" and "radial waves" patterns, respectively.
-
-   to do (someday, maybe):
-    - handle quoted command-line args (especially filenames with spaces)
-    - finish resizable checkerboard-gradient (sizes 4-128?)
-    - use %.1023s to simplify truncation of title-bar string?
-    - have minimum window width:  oh well
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.01:  initial public release
-    - 1.02:  fixed cut-and-paste error in usage screen (oops...)
-    - 1.03:  modified to allow abbreviated options
-    - 1.04:  removed bogus extra argument from usage fprintf() [Glenn R-P?];
-              fixed command-line parsing bug
-    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
-    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
-    - 1.21:  made minor tweak to usage screen to fit within 25-line console
-    - 1.22:  added AMD64/EM64T support (__x86_64__)
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed 64-bit typo in readpng2.c
-    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
-              unexpected-EOF and file-read-error cases
-    - 2.03:  removed runtime MMX-enabling/disabling and obsolete -mmx* options
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng2-win"
-#define LONGNAME  "Progressive PNG Viewer for Windows"
-#define VERSION   "2.02 of 16 March 2008"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <setjmp.h>    /* for jmpbuf declaration in readpng2.h */
-#include <time.h>
-#include <math.h>      /* only for PvdM background code */
-#include <windows.h>
-#ifdef __CYGWIN__
-/* getch replacement. Turns out, we don't really need this,
- * but leave it here if we ever enable any of the uses of
- * _getch in the main code
- */
-#include <unistd.h>
-#include <termio.h>
-#include <sys/ioctl.h>
-int repl_getch( void )
-{
-  char ch;
-  int fd = fileno(stdin);
-  struct termio old_tty, new_tty;
-
-  ioctl(fd, TCGETA, &old_tty);
-  new_tty = old_tty;
-  new_tty.c_lflag &= ~(ICANON | ECHO | ISIG);
-  ioctl(fd, TCSETA, &new_tty);
-  fread(&ch, 1, sizeof(ch), stdin);
-  ioctl(fd, TCSETA, &old_tty);
-
-  return ch;
-}
-#define _getch repl_getch
-#else
-#include <conio.h>     /* only for _getch() */
-#endif
-
-/* all for PvdM background code: */
-#ifndef PI
-#  define PI             3.141592653589793238
-#endif
-#define PI_2             (PI*0.5)
-#define INV_PI_360       (360.0 / PI)
-#define MAX(a,b)         (a>b?a:b)
-#define MIN(a,b)         (a<b?a:b)
-#define CLIP(a,min,max)  MAX(min,MIN((a),max))
-#define ABS(a)           ((a)<0?-(a):(a))
-#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
-#define ROUNDF(f)        ((int)(f + 0.5))
-
-#define rgb1_max   bg_freq
-#define rgb1_min   bg_gray
-#define rgb2_max   bg_bsat
-#define rgb2_min   bg_brot
-
-/* #define DEBUG */     /* this enables the Trace() macros */
-
-#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
-
-
-/* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
-
-#define alpha_composite(composite, fg, alpha, bg) {               \
-    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
-                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
-    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
-}
-
-
-#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
-                          *  block size corresponds roughly to a download
-                          *  speed 10% faster than theoretical 33.6K maximum
-                          *  (assuming 8 data bits, 1 stop bit and no other
-                          *  overhead) */
-
-/* local prototypes */
-static void       rpng2_win_init(void);
-static int        rpng2_win_create_window(void);
-static int        rpng2_win_load_bg_image(void);
-static void       rpng2_win_display_row(ulg row);
-static void       rpng2_win_finish_display(void);
-static void       rpng2_win_cleanup(void);
-LRESULT CALLBACK  rpng2_win_wndproc(HWND, UINT, WPARAM, LPARAM);
-
-
-static char titlebar[1024];
-static char *progname = PROGNAME;
-static char *appname = LONGNAME;
-static char *filename;
-static FILE *infile;
-
-static mainprog_info rpng2_info;
-
-static uch inbuf[INBUFSIZE];
-static int incount;
-
-static int pat = 6;         /* must be less than num_bgpat */
-static int bg_image = 0;
-static int bgscale = 16;
-static ulg bg_rowbytes;
-static uch *bg_data;
-
-static struct rgb_color {
-    uch r, g, b;
-} rgb[] = {
-    {  0,   0,   0},    /*  0:  black */
-    {255, 255, 255},    /*  1:  white */
-    {173, 132,  57},    /*  2:  tan */
-    { 64, 132,   0},    /*  3:  medium green */
-    {189, 117,   1},    /*  4:  gold */
-    {253, 249,   1},    /*  5:  yellow */
-    {  0,   0, 255},    /*  6:  blue */
-    {  0,   0, 120},    /*  7:  medium blue */
-    {255,   0, 255},    /*  8:  magenta */
-    { 64,   0,  64},    /*  9:  dark magenta */
-    {255,   0,   0},    /* 10:  red */
-    { 64,   0,   0},    /* 11:  dark red */
-    {255, 127,   0},    /* 12:  orange */
-    {192,  96,   0},    /* 13:  darker orange */
-    { 24,  60,   0},    /* 14:  dark green-yellow */
-    { 85, 125, 200}     /* 15:  ice blue */
-};
-/* not used for now, but should be for error-checking:
-static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
- */
-
-/*
-    This whole struct is a fairly cheesy way to keep the number of
-    command-line options to a minimum.  The radial-waves background
-    type is a particularly poor fit to the integer elements of the
-    struct...but a few macros and a little fixed-point math will do
-    wonders for ya.
-
-    type bits:
-       F E D C B A 9 8 7 6 5 4 3 2 1 0
-                             | | | | |
-                             | | +-+-+-- 0 = sharp-edged checkerboard
-                             | |         1 = soft diamonds
-                             | |         2 = radial waves
-                             | |       3-7 = undefined
-                             | +-- gradient #2 inverted?
-                             +-- alternating columns inverted?
- */
-static struct background_pattern {
-    ush type;
-    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
-    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
-} bg[] = {
-    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
-    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
-    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
-    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
-    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
-    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
-    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
-    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
-    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
-    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
-    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
-    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
-    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
-    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
-    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
-    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
-};
-static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
-
-
-/* Windows-specific global variables (could go in struct, but messy...) */
-static ulg wimage_rowbytes;
-static uch *dib;
-static uch *wimage_data;
-static BITMAPINFOHEADER *bmih;
-
-static HWND global_hwnd;
-static HINSTANCE global_hInst;
-static int global_showmode;
-
-
-
-
-int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
-{
-    char *args[1024];                 /* arbitrary limit, but should suffice */
-    char **argv = args;
-    char *p, *q, *bgstr = NULL;
-    int argc = 0;
-    int rc, alen, flen;
-    int error = 0;
-    int timing = FALSE;
-    int have_bg = FALSE;
-    double LUT_exponent;              /* just the lookup table */
-    double CRT_exponent = 2.2;        /* just the monitor */
-    double default_display_exponent;  /* whole display system */
-    MSG msg;
-
-
-    /* First initialize a few things, just to be sure--memset takes care of
-     * default background color (black), booleans (FALSE), pointers (NULL),
-     * etc. */
-
-    global_hInst = hInst;
-    global_showmode = showmode;
-    filename = (char *)NULL;
-    memset(&rpng2_info, 0, sizeof(mainprog_info));
-
-#ifndef __CYGWIN__
-    /* Next reenable console output, which normally goes to the bit bucket
-     * for windowed apps.  Closing the console window will terminate the
-     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
-     * incantation. */
-
-    AllocConsole();
-    freopen("CONOUT$", "a", stderr);
-    freopen("CONOUT$", "a", stdout);
-#endif
-
-    /* Set the default value for our display-system exponent, i.e., the
-     * product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  This is not an
-     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
-     * ones), but it should cover 99% of the current possibilities.  And
-     * yes, these ifdefs are completely wasted in a Windows program... */
-
-#if defined(NeXT)
-    /* third-party utilities can modify the default LUT exponent */
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to
-     * get the "gamma" value, so we do it the hard way */
-    infile = fopen("/etc/config/system.glGammaVal", "r");
-    if (infile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, infile);
-        fclose(infile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL)
-        rpng2_info.display_exponent = atof(p);
-    else
-        rpng2_info.display_exponent = default_display_exponent;
-
-
-    /* Windows really hates command lines, so we have to set up our own argv.
-     * Note that we do NOT bother with quoted arguments here, so don't use
-     * filenames with spaces in 'em! */
-
-    argv[argc++] = PROGNAME;
-    p = cmd;
-    for (;;) {
-        if (*p == ' ')
-            while (*++p == ' ')
-                ;
-        /* now p points at the first non-space after some spaces */
-        if (*p == '\0')
-            break;    /* nothing after the spaces:  done */
-        argv[argc++] = q = p;
-        while (*q && *q != ' ')
-            ++q;
-        /* now q points at a space or the end of the string */
-        if (*q == '\0')
-            break;    /* last argv already terminated; quit */
-        *q = '\0';    /* change space to terminator */
-        p = q + 1;
-    }
-    argv[argc] = NULL;   /* terminate the argv array itself */
-
-
-    /* Now parse the command line for options and the PNG filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                rpng2_info.display_exponent = atof(*argv);
-                if (rpng2_info.display_exponent <= 0.0)
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else {
-                    have_bg = TRUE;
-                    bg_image = FALSE;
-                }
-            }
-        } else if (!strncmp(*argv, "-bgpat", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                pat = atoi(*argv) - 1;
-                if (pat < 0 || pat >= num_bgpat)
-                    ++error;
-                else {
-                    bg_image = TRUE;
-                    have_bg = FALSE;
-                }
-            }
-        } else if (!strncmp(*argv, "-timing", 2)) {
-            timing = TRUE;
-        } else {
-            if (**argv != '-') {
-                filename = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-    if (!filename)
-        ++error;
-
-
-    /* print usage screen if any errors up to this point */
-
-    if (error) {
-#ifndef __CYGWIN__
-        int ch;
-#endif
-
-        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
-        readpng2_version_info();
-        fprintf(stderr, "\n"
-          "Usage:  %s [-gamma exp] [-bgcolor bg | -bgpat pat] [-timing]\n"
-          "        %*s file.png\n\n"
-          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
-          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
-          "    bg  \tdesired background color in 7-character hex RGB format\n"
-          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
-          "\t\t  used with transparent images; overrides -bgpat option\n"
-          "    pat \tdesired background pattern number (1-%d); used with\n"
-          "\t\t  transparent images; overrides -bgcolor option\n"
-          "    -timing\tenables delay for every block read, to simulate modem\n"
-          "\t\t  download of image (~36 Kbps)\n"
-          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
-#ifndef __CYGWIN__
-          "Press Q or Esc to quit this usage screen. ",
-#else
-          ,
-#endif
-          PROGNAME,
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__)) && \
-    !(defined(__CYGWIN__) || defined(__MINGW32__))
-          (int)strlen(PROGNAME), " ",
-#endif
-          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat);
-        fflush(stderr);
-#ifndef __CYGWIN__
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-#endif
-        exit(1);
-    }
-
-
-    if (!(infile = fopen(filename, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
-        ++error;
-    } else {
-        incount = fread(inbuf, 1, INBUFSIZE, infile);
-        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
-            fprintf(stderr, PROGNAME
-              ":  [%s] is not a PNG file: incorrect signature\n",
-              filename);
-            ++error;
-        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
-            switch (rc) {
-                case 2:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
-                    break;
-                case 4:
-                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                    break;
-                default:
-                    fprintf(stderr, PROGNAME
-                      ":  unknown readpng2_init() error\n");
-                    break;
-            }
-            ++error;
-        }
-        if (error)
-            fclose(infile);
-    }
-
-
-    if (error) {
-#ifndef __CYGWIN__
-        int ch;
-#endif
-
-        fprintf(stderr, PROGNAME ":  aborting.\n");
-#ifndef __CYGWIN__
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-#endif
-        exit(2);
-    } else {
-        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
-#ifndef __CYGWIN__
-        fprintf(stderr,
-          "\n   [console window:  closing this window will terminate %s]\n\n",
-          PROGNAME);
-#endif
-        fflush(stderr);
-    }
-
-
-    /* set the title-bar string, but make sure buffer doesn't overflow */
-
-    alen = strlen(appname);
-    flen = strlen(filename);
-    if (alen + flen + 3 > 1023)
-        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
-    else
-        sprintf(titlebar, "%s:  %s", appname, filename);
-
-
-    /* set some final rpng2_info variables before entering main data loop */
-
-    if (have_bg) {
-        unsigned r, g, b;   /* this approach quiets compiler warnings */
-
-        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-        rpng2_info.bg_red   = (uch)r;
-        rpng2_info.bg_green = (uch)g;
-        rpng2_info.bg_blue  = (uch)b;
-    } else
-        rpng2_info.need_bgcolor = TRUE;
-
-    rpng2_info.state = kPreInit;
-    rpng2_info.mainprog_init = rpng2_win_init;
-    rpng2_info.mainprog_display_row = rpng2_win_display_row;
-    rpng2_info.mainprog_finish_display = rpng2_win_finish_display;
-
-
-    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
-     * the loop to deal with our first buffer of data (read in above to verify
-     * that the file is a PNG image), then loop through the file and continue
-     * calling the same routine to handle each chunk of data.  It in turn
-     * passes the data to libpng, which will invoke one or more of our call-
-     * backs as decoded data become available.  We optionally call Sleep() for
-     * one second per iteration to simulate downloading the image via an analog
-     * modem. */
-
-    for (;;) {
-        Trace((stderr, "about to call readpng2_decode_data()\n"))
-        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
-            ++error;
-        Trace((stderr, "done with readpng2_decode_data()\n"))
-
-        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
-            if (rpng2_info.state == kDone) {
-                Trace((stderr, "done decoding PNG image\n"))
-            } else if (ferror(infile)) {
-                fprintf(stderr, PROGNAME
-                  ":  error while reading PNG image file\n");
-                exit(3);
-            } else if (feof(infile)) {
-                fprintf(stderr, PROGNAME ":  end of file reached "
-                  "(unexpectedly) while reading PNG image file\n");
-                exit(3);
-            } else /* if (error) */ {
-                /* will print error message below */
-            }
-            break;
-        }
-
-        if (timing)
-            Sleep(1000L);
-
-        incount = fread(inbuf, 1, INBUFSIZE, infile);
-    }
-
-
-    /* clean up PNG stuff and report any decoding errors */
-
-    fclose(infile);
-    Trace((stderr, "about to call readpng2_cleanup()\n"))
-    readpng2_cleanup(&rpng2_info);
-
-    if (error) {
-        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
-        exit(3);
-    }
-
-
-    /* wait for the user to tell us when to quit */
-
-    while (GetMessage(&msg, NULL, 0, 0)) {
-        TranslateMessage(&msg);
-        DispatchMessage(&msg);
-    }
-
-
-    /* we're done:  clean up all image and Windows resources and go away */
-
-    Trace((stderr, "about to call rpng2_win_cleanup()\n"))
-    rpng2_win_cleanup();
-
-    return msg.wParam;
-}
-
-
-
-
-
-/* this function is called by readpng2_info_callback() in readpng2.c, which
- * in turn is called by libpng after all of the pre-IDAT chunks have been
- * read and processed--i.e., we now have enough info to finish initializing */
-
-static void rpng2_win_init()
-{
-    ulg i;
-    ulg rowbytes = rpng2_info.rowbytes;
-
-    Trace((stderr, "beginning rpng2_win_init()\n"))
-    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
-    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
-    Trace((stderr, "  height = %ld\n", rpng2_info.height))
-
-    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
-    if (!rpng2_info.image_data) {
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
-    if (!rpng2_info.row_pointers) {
-        free(rpng2_info.image_data);
-        rpng2_info.image_data = NULL;
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    for (i = 0;  i < rpng2_info.height;  ++i)
-        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
-
-/*---------------------------------------------------------------------------
-    Do the basic Windows initialization stuff, make the window, and fill it
-    with the user-specified, file-specified or default background color.
-  ---------------------------------------------------------------------------*/
-
-    if (rpng2_win_create_window()) {
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    rpng2_info.state = kWindowInit;
-}
-
-
-
-
-
-static int rpng2_win_create_window()
-{
-    uch bg_red   = rpng2_info.bg_red;
-    uch bg_green = rpng2_info.bg_green;
-    uch bg_blue  = rpng2_info.bg_blue;
-    uch *dest;
-    int extra_width, extra_height;
-    ulg i, j;
-    WNDCLASSEX wndclass;
-    RECT rect;
-
-
-/*---------------------------------------------------------------------------
-    Allocate memory for the display-specific version of the image (round up
-    to multiple of 4 for Windows DIB).
-  ---------------------------------------------------------------------------*/
-
-    wimage_rowbytes = ((3*rpng2_info.width + 3L) >> 2) << 2;
-
-    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
-                              wimage_rowbytes*rpng2_info.height)))
-    {
-        return 4;   /* fail */
-    }
-
-/*---------------------------------------------------------------------------
-    Initialize the DIB.  Negative height means to use top-down BMP ordering
-    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
-    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
-    directly => wimage_data begins immediately after BMP header.
-  ---------------------------------------------------------------------------*/
-
-    memset(dib, 0, sizeof(BITMAPINFOHEADER));
-    bmih = (BITMAPINFOHEADER *)dib;
-    bmih->biSize = sizeof(BITMAPINFOHEADER);
-    bmih->biWidth = rpng2_info.width;
-    bmih->biHeight = -((long)rpng2_info.height);
-    bmih->biPlanes = 1;
-    bmih->biBitCount = 24;
-    bmih->biCompression = 0;
-    wimage_data = dib + sizeof(BITMAPINFOHEADER);
-
-/*---------------------------------------------------------------------------
-    Fill window with the specified background color (default is black), but
-    defer loading faked "background image" until window is displayed (may be
-    slow to compute).  Data are in BGR order.
-  ---------------------------------------------------------------------------*/
-
-    if (bg_image) {   /* just fill with black for now */
-        memset(wimage_data, 0, wimage_rowbytes*rpng2_info.height);
-    } else {
-        for (j = 0;  j < rpng2_info.height;  ++j) {
-            dest = wimage_data + j*wimage_rowbytes;
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                *dest++ = bg_blue;
-                *dest++ = bg_green;
-                *dest++ = bg_red;
-            }
-        }
-    }
-
-/*---------------------------------------------------------------------------
-    Set the window parameters.
-  ---------------------------------------------------------------------------*/
-
-    memset(&wndclass, 0, sizeof(wndclass));
-
-    wndclass.cbSize = sizeof(wndclass);
-    wndclass.style = CS_HREDRAW | CS_VREDRAW;
-    wndclass.lpfnWndProc = rpng2_win_wndproc;
-    wndclass.hInstance = global_hInst;
-    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
-    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
-    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
-    wndclass.lpszMenuName = NULL;
-    wndclass.lpszClassName = progname;
-    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
-
-    RegisterClassEx(&wndclass);
-
-/*---------------------------------------------------------------------------
-    Finally, create the window.
-  ---------------------------------------------------------------------------*/
-
-    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
-                      GetSystemMetrics(SM_CXDLGFRAME));
-    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
-                      GetSystemMetrics(SM_CYDLGFRAME)) +
-                      GetSystemMetrics(SM_CYCAPTION);
-
-    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
-      CW_USEDEFAULT, CW_USEDEFAULT, rpng2_info.width+extra_width,
-      rpng2_info.height+extra_height, NULL, NULL, global_hInst, NULL);
-
-    ShowWindow(global_hwnd, global_showmode);
-    UpdateWindow(global_hwnd);
-
-/*---------------------------------------------------------------------------
-    Now compute the background image and display it.  If it fails (memory
-    allocation), revert to a plain background color.
-  ---------------------------------------------------------------------------*/
-
-    if (bg_image) {
-        static const char *msg = "Computing background image...";
-        int x, y, len = strlen(msg);
-        HDC hdc = GetDC(global_hwnd);
-        TEXTMETRIC tm;
-
-        GetTextMetrics(hdc, &tm);
-        x = (rpng2_info.width - len*tm.tmAveCharWidth)/2;
-        y = (rpng2_info.height - tm.tmHeight)/2;
-        SetBkMode(hdc, TRANSPARENT);
-        SetTextColor(hdc, GetSysColor(COLOR_HIGHLIGHTTEXT));
-        /* this can still begin out of bounds even if x is positive (???): */
-        TextOut(hdc, ((x < 0)? 0 : x), ((y < 0)? 0 : y), msg, len);
-        ReleaseDC(global_hwnd, hdc);
-
-        rpng2_win_load_bg_image();   /* resets bg_image if fails */
-    }
-
-    if (!bg_image) {
-        for (j = 0;  j < rpng2_info.height;  ++j) {
-            dest = wimage_data + j*wimage_rowbytes;
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                *dest++ = bg_blue;
-                *dest++ = bg_green;
-                *dest++ = bg_red;
-            }
-        }
-    }
-
-    rect.left = 0L;
-    rect.top = 0L;
-    rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
-    rect.bottom = (LONG)rpng2_info.height;     /* possibly off by one? */
-    InvalidateRect(global_hwnd, &rect, FALSE);
-    UpdateWindow(global_hwnd);                 /* similar to XFlush() */
-
-    return 0;
-
-} /* end function rpng2_win_create_window() */
-
-
-
-
-
-static int rpng2_win_load_bg_image()
-{
-    uch *src, *dest;
-    uch r1, r2, g1, g2, b1, b2;
-    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
-    int k, hmax, max;
-    int xidx, yidx, yidx_max = (bgscale-1);
-    int even_odd_vert, even_odd_horiz, even_odd;
-    int invert_gradient2 = (bg[pat].type & 0x08);
-    int invert_column;
-    ulg i, row;
-
-/*---------------------------------------------------------------------------
-    Allocate buffer for fake background image to be used with transparent
-    images; if this fails, revert to plain background color.
-  ---------------------------------------------------------------------------*/
-
-    bg_rowbytes = 3 * rpng2_info.width;
-    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
-    if (!bg_data) {
-        fprintf(stderr, PROGNAME
-          ":  unable to allocate memory for background image\n");
-        bg_image = 0;
-        return 1;
-    }
-
-/*---------------------------------------------------------------------------
-    Vertical gradients (ramps) in NxN squares, alternating direction and
-    colors (N == bgscale).
-  ---------------------------------------------------------------------------*/
-
-    if ((bg[pat].type & 0x07) == 0) {
-        uch r1_min  = rgb[bg[pat].rgb1_min].r;
-        uch g1_min  = rgb[bg[pat].rgb1_min].g;
-        uch b1_min  = rgb[bg[pat].rgb1_min].b;
-        uch r2_min  = rgb[bg[pat].rgb2_min].r;
-        uch g2_min  = rgb[bg[pat].rgb2_min].g;
-        uch b2_min  = rgb[bg[pat].rgb2_min].b;
-        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
-        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
-        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
-        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
-        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
-        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = row % bgscale;
-            even_odd_vert = (row / bgscale) & 1;
-
-            r1 = r1_min + (r1_diff * yidx) / yidx_max;
-            g1 = g1_min + (g1_diff * yidx) / yidx_max;
-            b1 = b1_min + (b1_diff * yidx) / yidx_max;
-            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
-            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
-            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
-
-            r2 = r2_min + (r2_diff * yidx) / yidx_max;
-            g2 = g2_min + (g2_diff * yidx) / yidx_max;
-            b2 = b2_min + (b2_diff * yidx) / yidx_max;
-            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
-            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
-            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
-
-            dest = bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                even_odd_horiz = (i / bgscale) & 1;
-                even_odd = even_odd_vert ^ even_odd_horiz;
-                invert_column =
-                  (even_odd_horiz && (bg[pat].type & 0x10));
-                if (even_odd == 0) {         /* gradient #1 */
-                    if (invert_column) {
-                        *dest++ = r1_inv;
-                        *dest++ = g1_inv;
-                        *dest++ = b1_inv;
-                    } else {
-                        *dest++ = r1;
-                        *dest++ = g1;
-                        *dest++ = b1;
-                    }
-                } else {                     /* gradient #2 */
-                    if ((invert_column && invert_gradient2) ||
-                        (!invert_column && !invert_gradient2))
-                    {
-                        *dest++ = r2;        /* not inverted or */
-                        *dest++ = g2;        /*  doubly inverted */
-                        *dest++ = b2;
-                    } else {
-                        *dest++ = r2_inv;
-                        *dest++ = g2_inv;    /* singly inverted */
-                        *dest++ = b2_inv;
-                    }
-                }
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
-    M. Costello.
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 1) {
-
-        hmax = (bgscale-1)/2;   /* half the max weight of a color */
-        max = 2*hmax;           /* the max weight of a color */
-
-        r1 = rgb[bg[pat].rgb1_max].r;
-        g1 = rgb[bg[pat].rgb1_max].g;
-        b1 = rgb[bg[pat].rgb1_max].b;
-        r2 = rgb[bg[pat].rgb2_max].r;
-        g2 = rgb[bg[pat].rgb2_max].g;
-        b2 = rgb[bg[pat].rgb2_max].b;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = row % bgscale;
-            if (yidx > hmax)
-                yidx = bgscale-1 - yidx;
-            dest = bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                xidx = i % bgscale;
-                if (xidx > hmax)
-                    xidx = bgscale-1 - xidx;
-                k = xidx + yidx;
-                *dest++ = (k*r1 + (max-k)*r2) / max;
-                *dest++ = (k*g1 + (max-k)*g2) / max;
-                *dest++ = (k*b1 + (max-k)*b2) / max;
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
-    soids will equal bgscale?].  This one is slow but very cool.  Code con-
-    tributed by Pieter S. van der Meulen (originally in Smalltalk).
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 2) {
-        uch ch;
-        int ii, x, y, hw, hh, grayspot;
-        double freq, rotate, saturate, gray, intensity;
-        double angle=0.0, aoffset=0.0, maxDist, dist;
-        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
-
-        fprintf(stderr, "%s:  computing radial background...",
-          PROGNAME);
-        fflush(stderr);
-
-        hh = rpng2_info.height / 2;
-        hw = rpng2_info.width / 2;
-
-        /* variables for radial waves:
-         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
-         *   freq:  number of color beams originating from the center
-         *   grayspot:  size of the graying center area (anti-alias)
-         *   rotate:  rotation of the beams as a function of radius
-         *   saturate:  saturation of beams' shape azimuthally
-         */
-        angle = CLIP(angle, 0.0, 360.0);
-        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
-        freq = MAX((double)bg[pat].bg_freq, 0.0);
-        saturate = (double)bg[pat].bg_bsat * 0.1;
-        rotate = (double)bg[pat].bg_brot * 0.1;
-        gray = 0.0;
-        intensity = 0.0;
-        maxDist = (double)((hw*hw) + (hh*hh));
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            y = row - hh;
-            dest = bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                x = i - hw;
-                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
-                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
-                gray = MIN(1.0, gray);
-                dist = (double)((x*x) + (y*y)) / maxDist;
-                intensity = cos((angle+(rotate*dist*PI)) * freq) *
-                  gray * saturate;
-                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
-                hue = (angle + PI) * INV_PI_360 + aoffset;
-                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
-                s = MIN(MAX(s,0.0), 1.0);
-                v = MIN(MAX(intensity,0.0), 1.0);
-
-                if (s == 0.0) {
-                    ch = (uch)(v * 255.0);
-                    *dest++ = ch;
-                    *dest++ = ch;
-                    *dest++ = ch;
-                } else {
-                    if ((hue < 0.0) || (hue >= 360.0))
-                        hue -= (((int)(hue / 360.0)) * 360.0);
-                    hue /= 60.0;
-                    ii = (int)hue;
-                    f = hue - (double)ii;
-                    p = (1.0 - s) * v;
-                    q = (1.0 - (s * f)) * v;
-                    t = (1.0 - (s * (1.0 - f))) * v;
-                    if      (ii == 0) { red = v; green = t; blue = p; }
-                    else if (ii == 1) { red = q; green = v; blue = p; }
-                    else if (ii == 2) { red = p; green = v; blue = t; }
-                    else if (ii == 3) { red = p; green = q; blue = v; }
-                    else if (ii == 4) { red = t; green = p; blue = v; }
-                    else if (ii == 5) { red = v; green = p; blue = q; }
-                    *dest++ = (uch)(red * 255.0);
-                    *dest++ = (uch)(green * 255.0);
-                    *dest++ = (uch)(blue * 255.0);
-                }
-            }
-        }
-        fprintf(stderr, "done.\n");
-        fflush(stderr);
-    }
-
-/*---------------------------------------------------------------------------
-    Blast background image to display buffer before beginning PNG decode;
-    calling function will handle invalidation and UpdateWindow() call.
-  ---------------------------------------------------------------------------*/
-
-    for (row = 0;  row < rpng2_info.height;  ++row) {
-        src = bg_data + row*bg_rowbytes;
-        dest = wimage_data + row*wimage_rowbytes;
-        for (i = rpng2_info.width;  i > 0;  --i) {
-            r1 = *src++;
-            g1 = *src++;
-            b1 = *src++;
-            *dest++ = b1;
-            *dest++ = g1;   /* note reverse order */
-            *dest++ = r1;
-        }
-    }
-
-    return 0;
-
-} /* end function rpng2_win_load_bg_image() */
-
-
-
-
-
-static void rpng2_win_display_row(ulg row)
-{
-    uch bg_red   = rpng2_info.bg_red;
-    uch bg_green = rpng2_info.bg_green;
-    uch bg_blue  = rpng2_info.bg_blue;
-    uch *src, *src2=NULL, *dest;
-    uch r, g, b, a;
-    ulg i;
-    static int rows=0;
-    static ulg firstrow;
-
-/*---------------------------------------------------------------------------
-    rows and firstrow simply track how many rows (and which ones) have not
-    yet been displayed; alternatively, we could call InvalidateRect() for
-    every row and not bother with the records-keeping.
-  ---------------------------------------------------------------------------*/
-
-    Trace((stderr, "beginning rpng2_win_display_row()\n"))
-
-    if (rows == 0)
-        firstrow = row;   /* first row not yet displayed */
-
-    ++rows;   /* count of rows received but not yet displayed */
-
-/*---------------------------------------------------------------------------
-    Aside from the use of the rpng2_info struct and the lack of an outer
-    loop (over rows), this routine is identical to rpng_win_display_image()
-    in the non-progressive version of the program.
-  ---------------------------------------------------------------------------*/
-
-    src = rpng2_info.image_data + row*rpng2_info.rowbytes;
-    if (bg_image)
-        src2 = bg_data + row*bg_rowbytes;
-    dest = wimage_data + row*wimage_rowbytes;
-
-    if (rpng2_info.channels == 3) {
-        for (i = rpng2_info.width;  i > 0;  --i) {
-            r = *src++;
-            g = *src++;
-            b = *src++;
-            *dest++ = b;
-            *dest++ = g;   /* note reverse order */
-            *dest++ = r;
-        }
-    } else /* if (rpng2_info.channels == 4) */ {
-        for (i = rpng2_info.width;  i > 0;  --i) {
-            r = *src++;
-            g = *src++;
-            b = *src++;
-            a = *src++;
-            if (bg_image) {
-                bg_red   = *src2++;
-                bg_green = *src2++;
-                bg_blue  = *src2++;
-            }
-            if (a == 255) {
-                *dest++ = b;
-                *dest++ = g;
-                *dest++ = r;
-            } else if (a == 0) {
-                *dest++ = bg_blue;
-                *dest++ = bg_green;
-                *dest++ = bg_red;
-            } else {
-                /* this macro (copied from png.h) composites the
-                 * foreground and background values and puts the
-                 * result into the first argument; there are no
-                 * side effects with the first argument */
-                alpha_composite(*dest++, b, a, bg_blue);
-                alpha_composite(*dest++, g, a, bg_green);
-                alpha_composite(*dest++, r, a, bg_red);
-            }
-        }
-    }
-
-/*---------------------------------------------------------------------------
-    Display after every 16 rows or when on last row.  (Region may include
-    previously displayed lines due to interlacing--i.e., not contiguous.)
-  ---------------------------------------------------------------------------*/
-
-    if ((rows & 0xf) == 0 || row == rpng2_info.height-1) {
-        RECT rect;
-
-        rect.left = 0L;
-        rect.top = (LONG)firstrow;
-        rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
-        rect.bottom = (LONG)row + 1L;              /* possibly off by one? */
-        InvalidateRect(global_hwnd, &rect, FALSE);
-        UpdateWindow(global_hwnd);                 /* similar to XFlush() */
-        rows = 0;
-    }
-
-} /* end function rpng2_win_display_row() */
-
-
-
-
-
-static void rpng2_win_finish_display()
-{
-    Trace((stderr, "beginning rpng2_win_finish_display()\n"))
-
-    /* last row has already been displayed by rpng2_win_display_row(), so
-     * we have nothing to do here except set a flag and let the user know
-     * that the image is done */
-
-    rpng2_info.state = kDone;
-    printf(
-#ifndef __CYGWIN__
-      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n"
-#else
-      "Done.  Press mouse button 1 (within image window) to quit.\n"
-#endif
-    );
-    fflush(stdout);
-}
-
-
-
-
-
-static void rpng2_win_cleanup()
-{
-    if (bg_image && bg_data) {
-        free(bg_data);
-        bg_data = NULL;
-    }
-
-    if (rpng2_info.image_data) {
-        free(rpng2_info.image_data);
-        rpng2_info.image_data = NULL;
-    }
-
-    if (rpng2_info.row_pointers) {
-        free(rpng2_info.row_pointers);
-        rpng2_info.row_pointers = NULL;
-    }
-
-    if (dib) {
-        free(dib);
-        dib = NULL;
-    }
-}
-
-
-
-
-
-LRESULT CALLBACK rpng2_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
-{
-    HDC         hdc;
-    PAINTSTRUCT ps;
-    int rc;
-
-    switch (iMsg) {
-        case WM_CREATE:
-            /* one-time processing here, if any */
-            return 0;
-
-        case WM_PAINT:
-            hdc = BeginPaint(hwnd, &ps);
-            rc = StretchDIBits(hdc, 0, 0, rpng2_info.width, rpng2_info.height,
-                                    0, 0, rpng2_info.width, rpng2_info.height,
-                                    wimage_data, (BITMAPINFO *)bmih,
-                                    0, SRCCOPY);
-            EndPaint(hwnd, &ps);
-            return 0;
-
-        /* wait for the user to tell us when to quit */
-        case WM_CHAR:
-            switch (wP) {       /* only need one, so ignore repeat count */
-                case 'q':
-                case 'Q':
-                case 0x1B:      /* Esc key */
-                    PostQuitMessage(0);
-            }
-            return 0;
-
-        case WM_LBUTTONDOWN:    /* another way of quitting */
-        case WM_DESTROY:
-            PostQuitMessage(0);
-            return 0;
-    }
-
-    return DefWindowProc(hwnd, iMsg, wP, lP);
-}
diff --git a/extern/libpng/include/contrib/gregbook/rpng2-x.c b/extern/libpng/include/contrib/gregbook/rpng2-x.c
deleted file mode 100644
index 7f24b632be..0000000000
--- a/extern/libpng/include/contrib/gregbook/rpng2-x.c
+++ /dev/null
@@ -1,2107 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                  rpng2-x.c
-
-   This program decodes and displays PNG files progressively, as if it were
-   a web browser (though the front end is only set up to read from files).
-   It supports gamma correction, user-specified background colors, and user-
-   specified background patterns (for transparent images).  This version is
-   for the X Window System (tested by the author under Unix and by Martin
-   Zinser under OpenVMS; may work under OS/2 with a little tweaking).
-
-   Thanks to Adam Costello and Pieter S. van der Meulen for the "diamond"
-   and "radial waves" patterns, respectively.
-
-   to do (someday, maybe):
-    - fix expose/redraw code:  don't draw entire row if only part exposed
-    - 8-bit (colormapped) X support
-    - finish resizable checkerboard-gradient (sizes 4-128?)
-    - use %.1023s to simplify truncation of title-bar string?
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.01:  initial public release
-    - 1.02:  modified to allow abbreviated options; fixed char/uchar mismatch
-    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
-    - 1.11:  added -usleep option for demos; fixed command-line parsing bug
-    - 1.12:  added -pause option for demos and testing
-    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
-    - 1.21:  fixed some small X memory leaks (thanks to Fran�ois Petitjean)
-    - 1.22:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
-    - 1.23:  added -bgpat 0 mode (std white/gray checkerboard, 8x8 squares)
-    - 1.30:  added -loop option for -bgpat (ifdef FEATURE_LOOP); fixed bpp =
-              24; added support for X resources (thanks to Gerhard Niklasch)
-    - 1.31:  added code to skip unused chunks (thanks to Glenn Randers-Pehrson)
-    - 1.32:  added AMD64/EM64T support (__x86_64__); added basic expose/redraw
-              handling
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed 64-bit typo in readpng2.c; fixed -pause usage description
-    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
-              unexpected-EOF and file-read-error cases; fixed Trace() cut-and-
-              paste bugs
-    - 2.03:  deleted runtime MMX-enabling/disabling and obsolete -mmx* options
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng2-x"
-#define LONGNAME  "Progressive PNG Viewer for X"
-#define VERSION   "2.03 of 25 February 2010"
-#define RESNAME   "rpng2"       /* our X resource application name */
-#define RESCLASS  "Rpng"       /* our X resource class name */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <ctype.h>
-#include <string.h>
-#include <setjmp.h>       /* for jmpbuf declaration in readpng2.h */
-#include <time.h>
-#include <math.h>         /* only for PvdM background code */
-#include <X11/Xlib.h>
-#include <X11/Xutil.h>
-#include <X11/Xos.h>
-#include <X11/keysym.h>   /* defines XK_* macros */
-
-#ifdef VMS
-#  include <unistd.h>
-#endif
-
-/* all for PvdM background code: */
-#ifndef PI
-#  define PI             3.141592653589793238
-#endif
-#define PI_2             (PI*0.5)
-#define INV_PI_360       (360.0 / PI)
-#define MAX(a,b)         (a>b?a:b)
-#define MIN(a,b)         (a<b?a:b)
-#define CLIP(a,min,max)  MAX(min,MIN((a),max))
-#define ABS(a)           ((a)<0?-(a):(a))
-#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
-#define ROUNDF(f)        ((int)(f + 0.5))
-
-#define QUIT(e,k) ((e.type == ButtonPress && e.xbutton.button == Button1) ||  \
-                  (e.type == KeyPress &&   /*  v--- or 1 for shifted keys */  \
-                  ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape)))
-
-#define NO_24BIT_MASKS /* undef case not fully written--only for redisplay() */
-
-#define rgb1_max   bg_freq
-#define rgb1_min   bg_gray
-#define rgb2_max   bg_bsat
-#define rgb2_min   bg_brot
-
-/* #define DEBUG */     /* this enables the Trace() macros */
-
-#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
-
-
-/* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
-
-#define alpha_composite(composite, fg, alpha, bg) {               \
-    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
-                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
-    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
-}
-
-
-#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
-                          *  block size corresponds roughly to a download
-                          *  speed 10% faster than theoretical 33.6K maximum
-                          *  (assuming 8 data bits, 1 stop bit and no other
-                          *  overhead) */
-
-/* local prototypes */
-static void rpng2_x_init (void);
-static int  rpng2_x_create_window (void);
-static int  rpng2_x_load_bg_image (void);
-static void rpng2_x_display_row (ulg row);
-static void rpng2_x_finish_display (void);
-static void rpng2_x_redisplay_image (ulg startcol, ulg startrow,
-                                     ulg width, ulg height);
-#ifdef FEATURE_LOOP
-static void rpng2_x_reload_bg_image (void);
-static int  is_number (char *p);
-#endif
-static void rpng2_x_cleanup (void);
-static int  rpng2_x_msb (ulg u32val);
-
-
-static char titlebar[1024], *window_name = titlebar;
-static char *appname = LONGNAME;
-static char *icon_name = PROGNAME;
-static char *res_name = RESNAME;
-static char *res_class = RESCLASS;
-static char *filename;
-static FILE *infile;
-
-static mainprog_info rpng2_info;
-
-static uch inbuf[INBUFSIZE];
-static int incount;
-
-static int pat = 6;        /* must be less than num_bgpat */
-static int bg_image = 0;
-static int bgscale, bgscale_default = 16;
-static ulg bg_rowbytes;
-static uch *bg_data;
-
-int pause_after_pass = FALSE;
-int demo_timing = FALSE;
-ulg usleep_duration = 0L;
-
-static struct rgb_color {
-    uch r, g, b;
-} rgb[] = {
-    {  0,   0,   0},    /*  0:  black */
-    {255, 255, 255},    /*  1:  white */
-    {173, 132,  57},    /*  2:  tan */
-    { 64, 132,   0},    /*  3:  medium green */
-    {189, 117,   1},    /*  4:  gold */
-    {253, 249,   1},    /*  5:  yellow */
-    {  0,   0, 255},    /*  6:  blue */
-    {  0,   0, 120},    /*  7:  medium blue */
-    {255,   0, 255},    /*  8:  magenta */
-    { 64,   0,  64},    /*  9:  dark magenta */
-    {255,   0,   0},    /* 10:  red */
-    { 64,   0,   0},    /* 11:  dark red */
-    {255, 127,   0},    /* 12:  orange */
-    {192,  96,   0},    /* 13:  darker orange */
-    { 24,  60,   0},    /* 14:  dark green-yellow */
-    { 85, 125, 200},    /* 15:  ice blue */
-    {192, 192, 192}     /* 16:  Netscape/Mosaic gray */
-};
-/* not used for now, but should be for error-checking:
-static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
- */
-
-/*
-    This whole struct is a fairly cheesy way to keep the number of
-    command-line options to a minimum.  The radial-waves background
-    type is a particularly poor fit to the integer elements of the
-    struct...but a few macros and a little fixed-point math will do
-    wonders for ya.
-
-    type bits:
-       F E D C B A 9 8 7 6 5 4 3 2 1 0
-                             | | | | |
-                             | | +-+-+-- 0 = sharp-edged checkerboard
-                             | |         1 = soft diamonds
-                             | |         2 = radial waves
-                             | |       3-7 = undefined
-                             | +-- gradient #2 inverted?
-                             +-- alternating columns inverted?
- */
-static struct background_pattern {
-    ush type;
-    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
-    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
-} bg[] = {
-    {0,     1,1, 16,16},        /* checkered:  white vs. light gray (basic) */
-    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
-    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
-    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
-    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
-    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
-    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
-    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
-    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
-    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
-    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
-    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
-    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
-    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
-    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
-    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
-    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
-};
-static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
-
-
-/* X-specific variables */
-static char *displayname;
-static XImage *ximage;
-static Display *display;
-static int depth;
-static Visual *visual;
-static XVisualInfo *visual_list;
-static int RShift, GShift, BShift;
-static ulg RMask, GMask, BMask;
-static Window window;
-static GC gc;
-static Colormap colormap;
-
-static int have_nondefault_visual = FALSE;
-static int have_colormap = FALSE;
-static int have_window = FALSE;
-static int have_gc = FALSE;
-
-
-
-
-int main(int argc, char **argv)
-{
-#ifdef sgi
-    char tmpline[80];
-#endif
-    char *p, *bgstr = NULL;
-    int rc, alen, flen;
-    int error = 0;
-    int timing = FALSE;
-    int have_bg = FALSE;
-#ifdef FEATURE_LOOP
-    int loop = FALSE;
-    long loop_interval = -1;            /* seconds (100,000 max) */
-#endif
-    double LUT_exponent;                /* just the lookup table */
-    double CRT_exponent = 2.2;          /* just the monitor */
-    double default_display_exponent;    /* whole display system */
-    XEvent e;
-    KeySym k;
-
-
-    /* First initialize a few things, just to be sure--memset takes care of
-     * default background color (black), booleans (FALSE), pointers (NULL),
-     * etc. */
-
-    displayname = (char *)NULL;
-    filename = (char *)NULL;
-    memset(&rpng2_info, 0, sizeof(mainprog_info));
-
-
-    /* Set the default value for our display-system exponent, i.e., the
-     * product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  This is not an
-     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
-     * ones), but it should cover 99% of the current possibilities. */
-
-#if defined(NeXT)
-    /* third-party utilities can modify the default LUT exponent */
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to
-     * get the "gamma" value, so we do it the hard way */
-    infile = fopen("/etc/config/system.glGammaVal", "r");
-    if (infile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, infile);
-        fclose(infile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL)
-        rpng2_info.display_exponent = atof(p);
-    else
-        rpng2_info.display_exponent = default_display_exponent;
-
-
-    /* Now parse the command line for options and the PNG filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-display", 2)) {
-            if (!*++argv)
-                ++error;
-            else
-                displayname = *argv;
-        } else if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                rpng2_info.display_exponent = atof(*argv);
-                if (rpng2_info.display_exponent <= 0.0)
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else {
-                    have_bg = TRUE;
-                    bg_image = FALSE;
-                }
-            }
-        } else if (!strncmp(*argv, "-bgpat", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                pat = atoi(*argv);
-                if (pat >= 0 && pat < num_bgpat) {
-                    bg_image = TRUE;
-                    have_bg = FALSE;
-                } else
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-usleep", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                usleep_duration = (ulg)atol(*argv);
-                demo_timing = TRUE;
-            }
-        } else if (!strncmp(*argv, "-pause", 2)) {
-            pause_after_pass = TRUE;
-        } else if (!strncmp(*argv, "-timing", 2)) {
-            timing = TRUE;
-#ifdef FEATURE_LOOP
-        } else if (!strncmp(*argv, "-loop", 2)) {
-            loop = TRUE;
-            if (!argv[1] || !is_number(argv[1]))
-                loop_interval = 2;
-            else {
-                ++argv;
-                loop_interval = atol(*argv);
-                if (loop_interval < 0)
-                    loop_interval = 2;
-                else if (loop_interval > 100000)   /* bit more than one day */
-                    loop_interval = 100000;
-            }
-#endif
-        } else {
-            if (**argv != '-') {
-                filename = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-    if (!filename)
-        ++error;
-
-
-    /* print usage screen if any errors up to this point */
-
-    if (error) {
-        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
-        readpng2_version_info();
-        fprintf(stderr, "\n"
-          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
-#ifdef FEATURE_LOOP
-          "        %*s [-usleep dur | -timing] [-pause] [-loop [sec]] file.png\n\n"
-#else
-          "        %*s [-usleep dur | -timing] [-pause] file.png\n\n"
-#endif
-          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
-          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
-          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
-          "    bg  \tdesired background color in 7-character hex RGB format\n"
-          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
-          "\t\t  used with transparent images; overrides -bgpat\n"
-          "    pat \tdesired background pattern number (0-%d); used with\n"
-          "\t\t  transparent images; overrides -bgcolor\n"
-#ifdef FEATURE_LOOP
-          "    -loop\tloops through background images after initial display\n"
-          "\t\t  is complete (depends on -bgpat)\n"
-          "    sec \tseconds to display each background image (default = 2)\n"
-#endif
-          "    dur \tduration in microseconds to wait after displaying each\n"
-          "\t\t  row (for demo purposes)\n"
-          "    -timing\tenables delay for every block read, to simulate modem\n"
-          "\t\t  download of image (~36 Kbps)\n"
-          "    -pause\tpauses after displaying each pass until mouse clicked\n"
-          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
-          "\n", PROGNAME,
-          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat-1);
-        exit(1);
-    }
-
-
-    if (!(infile = fopen(filename, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
-        ++error;
-    } else {
-        incount = fread(inbuf, 1, INBUFSIZE, infile);
-        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
-            fprintf(stderr, PROGNAME
-              ":  [%s] is not a PNG file: incorrect signature\n",
-              filename);
-            ++error;
-        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
-            switch (rc) {
-                case 2:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
-                    break;
-                case 4:
-                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                    break;
-                default:
-                    fprintf(stderr, PROGNAME
-                      ":  unknown readpng2_init() error\n");
-                    break;
-            }
-            ++error;
-        } else {
-            Trace((stderr, "about to call XOpenDisplay()\n"))
-            display = XOpenDisplay(displayname);
-            if (!display) {
-                readpng2_cleanup(&rpng2_info);
-                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
-                  displayname? displayname : "default");
-                ++error;
-            }
-        }
-        if (error)
-            fclose(infile);
-    }
-
-
-    if (error) {
-        fprintf(stderr, PROGNAME ":  aborting.\n");
-        exit(2);
-    }
-
-
-    /* set the title-bar string, but make sure buffer doesn't overflow */
-
-    alen = strlen(appname);
-    flen = strlen(filename);
-    if (alen + flen + 3 > 1023)
-        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
-    else
-        sprintf(titlebar, "%s:  %s", appname, filename);
-
-
-    /* set some final rpng2_info variables before entering main data loop */
-
-    if (have_bg) {
-        unsigned r, g, b;   /* this approach quiets compiler warnings */
-
-        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-        rpng2_info.bg_red   = (uch)r;
-        rpng2_info.bg_green = (uch)g;
-        rpng2_info.bg_blue  = (uch)b;
-    } else
-        rpng2_info.need_bgcolor = TRUE;
-
-    rpng2_info.state = kPreInit;
-    rpng2_info.mainprog_init = rpng2_x_init;
-    rpng2_info.mainprog_display_row = rpng2_x_display_row;
-    rpng2_info.mainprog_finish_display = rpng2_x_finish_display;
-
-
-    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
-     * the loop to deal with our first buffer of data (read in above to verify
-     * that the file is a PNG image), then loop through the file and continue
-     * calling the same routine to handle each chunk of data.  It in turn
-     * passes the data to libpng, which will invoke one or more of our call-
-     * backs as decoded data become available.  We optionally call sleep() for
-     * one second per iteration to simulate downloading the image via an analog
-     * modem. */
-
-    for (;;) {
-        Trace((stderr, "about to call readpng2_decode_data()\n"))
-        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
-            ++error;
-        Trace((stderr, "done with readpng2_decode_data()\n"))
-
-        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
-            if (rpng2_info.state == kDone) {
-                Trace((stderr, "done decoding PNG image\n"))
-            } else if (ferror(infile)) {
-                fprintf(stderr, PROGNAME
-                  ":  error while reading PNG image file\n");
-                exit(3);
-            } else if (feof(infile)) {
-                fprintf(stderr, PROGNAME ":  end of file reached "
-                  "(unexpectedly) while reading PNG image file\n");
-                exit(3);
-            } else /* if (error) */ {
-                /* will print error message below */
-            }
-            break;
-        }
-
-        if (timing)
-            sleep(1);
-
-        incount = fread(inbuf, 1, INBUFSIZE, infile);
-    }
-
-
-    /* clean up PNG stuff and report any decoding errors */
-
-    fclose(infile);
-    Trace((stderr, "about to call readpng2_cleanup()\n"))
-    readpng2_cleanup(&rpng2_info);
-
-    if (error) {
-        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
-        exit(3);
-    }
-
-
-#ifdef FEATURE_LOOP
-
-    if (loop && bg_image) {
-        Trace((stderr, "entering -loop loop (FEATURE_LOOP)\n"))
-        for (;;) {
-            int i, use_sleep;
-            struct timeval now, then;
-
-            /* get current time and add loop_interval to get target time */
-            if (gettimeofday(&then, NULL) == 0) {
-                then.tv_sec += loop_interval;
-                use_sleep = FALSE;
-            } else
-                use_sleep = TRUE;
-
-            /* do quick check for a quit event but don't wait for it */
-            /* GRR BUG:  should also check for Expose events and redraw... */
-            if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask, &e))
-                if (QUIT(e,k))
-                    break;
-
-            /* generate next background image */
-            if (++pat >= num_bgpat)
-                pat = 0;
-            rpng2_x_reload_bg_image();
-
-            /* wait for timeout, using whatever means are available */
-            if (use_sleep || gettimeofday(&now, NULL) != 0) {
-                for (i = loop_interval;  i > 0;  --i) {
-                    sleep(1);
-                    /* GRR BUG:  also need to check for Expose (and redraw!) */
-                    if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask,
-                        &e) && QUIT(e,k))
-                        break;
-                }
-            } else {
-                /* Y2038 BUG! */
-                if (now.tv_sec < then.tv_sec ||
-                    (now.tv_sec == then.tv_sec && now.tv_usec < then.tv_usec))
-                {
-                    int quit = FALSE;
-                    long seconds_to_go = then.tv_sec - now.tv_sec;
-                    long usleep_usec;
-
-                    /* basically chew up most of remaining loop-interval with
-                     *  calls to sleep(1) interleaved with checks for quit
-                     *  events, but also recalc time-to-go periodically; when
-                     *  done, clean up any remaining time with usleep() call
-                     *  (could also use SIGALRM, but signals are a pain...) */
-                    while (seconds_to_go-- > 1) {
-                        int seconds_done = 0;
-
-                        for (i = seconds_to_go;  i > 0 && !quit;  --i) {
-                            sleep(1);
-                            /* GRR BUG:  need to check for Expose and redraw */
-                            if (XCheckMaskEvent(display, KeyPressMask |
-                                ButtonPressMask, &e) && QUIT(e,k))
-                                quit = TRUE;
-                            if (++seconds_done > 1000)
-                                break;   /* time to redo seconds_to_go meas. */
-                        }
-                        if (quit)
-                            break;
-
-                        /* OK, more than 1000 seconds since last check:
-                         *  correct the time-to-go measurement for drift */
-                        if (gettimeofday(&now, NULL) == 0) {
-                            if (now.tv_sec >= then.tv_sec)
-                                break;
-                            seconds_to_go = then.tv_sec - now.tv_sec;
-                        } else
-                            ++seconds_to_go;  /* restore what we subtracted */
-                    }
-                    if (quit)
-                        break;   /* breaks outer do-loop, skips redisplay */
-
-                    /* since difference between "now" and "then" is already
-                     *  eaten up to within a couple of seconds, don't need to
-                     *  worry about overflow--but might have overshot (neg.) */
-                    if (gettimeofday(&now, NULL) == 0) {
-                        usleep_usec = 1000000L*(then.tv_sec - now.tv_sec) +
-                          then.tv_usec - now.tv_usec;
-                        if (usleep_usec > 0)
-                            usleep((ulg)usleep_usec);
-                    }
-                }
-            }
-
-            /* composite image against new background and display (note that
-             *  we do not take into account the time spent doing this...) */
-            rpng2_x_redisplay_image (0, 0, rpng2_info.width, rpng2_info.height);
-        }
-
-    } else /* FALL THROUGH and do the normal thing */
-
-#endif /* FEATURE_LOOP */
-
-    /* wait for the user to tell us when to quit */
-
-    if (rpng2_info.state >= kWindowInit) {
-        Trace((stderr, "entering final wait-for-quit-event loop\n"))
-        do {
-            XNextEvent(display, &e);
-            if (e.type == Expose) {
-                XExposeEvent *ex = (XExposeEvent *)&e;
-                rpng2_x_redisplay_image (ex->x, ex->y, ex->width, ex->height);
-            }
-        } while (!QUIT(e,k));
-    } else {
-        fprintf(stderr, PROGNAME ":  init callback never called:  probable "
-          "libpng error while decoding PNG metadata\n");
-        exit(4);
-    }
-
-
-    /* we're done:  clean up all image and X resources and go away */
-
-    Trace((stderr, "about to call rpng2_x_cleanup()\n"))
-    rpng2_x_cleanup();
-
-    return 0;
-}
-
-
-
-
-
-/* this function is called by readpng2_info_callback() in readpng2.c, which
- * in turn is called by libpng after all of the pre-IDAT chunks have been
- * read and processed--i.e., we now have enough info to finish initializing */
-
-static void rpng2_x_init(void)
-{
-    ulg i;
-    ulg rowbytes = rpng2_info.rowbytes;
-
-    Trace((stderr, "beginning rpng2_x_init()\n"))
-    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
-    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
-    Trace((stderr, "  height = %ld\n", rpng2_info.height))
-
-    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
-    if (!rpng2_info.image_data) {
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
-    if (!rpng2_info.row_pointers) {
-        free(rpng2_info.image_data);
-        rpng2_info.image_data = NULL;
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    for (i = 0;  i < rpng2_info.height;  ++i)
-        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
-
-
-    /* do the basic X initialization stuff, make the window, and fill it with
-     * the user-specified, file-specified or default background color or
-     * pattern */
-
-    if (rpng2_x_create_window()) {
-
-        /* GRR TEMPORARY HACK:  this is fundamentally no different from cases
-         * above; libpng should call our error handler to longjmp() back to us
-         * when png_ptr goes away.  If we/it segfault instead, seems like a
-         * libpng bug... */
-
-        /* we're here via libpng callback, so if window fails, clean and bail */
-        readpng2_cleanup(&rpng2_info);
-        rpng2_x_cleanup();
-        exit(2);
-    }
-
-    rpng2_info.state = kWindowInit;
-}
-
-
-
-
-
-static int rpng2_x_create_window(void)
-{
-    ulg bg_red   = rpng2_info.bg_red;
-    ulg bg_green = rpng2_info.bg_green;
-    ulg bg_blue  = rpng2_info.bg_blue;
-    ulg bg_pixel = 0L;
-    ulg attrmask;
-    int need_colormap = FALSE;
-    int screen, pad;
-    uch *xdata;
-    Window root;
-    XEvent e;
-    XGCValues gcvalues;
-    XSetWindowAttributes attr;
-    XTextProperty windowName, *pWindowName = &windowName;
-    XTextProperty iconName, *pIconName = &iconName;
-    XVisualInfo visual_info;
-    XSizeHints *size_hints;
-    XWMHints *wm_hints;
-    XClassHint *class_hints;
-
-
-    Trace((stderr, "beginning rpng2_x_create_window()\n"))
-
-    screen = DefaultScreen(display);
-    depth = DisplayPlanes(display, screen);
-    root = RootWindow(display, screen);
-
-#ifdef DEBUG
-    XSynchronize(display, True);
-#endif
-
-    if (depth != 16 && depth != 24 && depth != 32) {
-        int visuals_matched = 0;
-
-        Trace((stderr, "default depth is %d:  checking other visuals\n",
-          depth))
-
-        /* 24-bit first */
-        visual_info.screen = screen;
-        visual_info.depth = 24;
-        visual_list = XGetVisualInfo(display,
-          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
-        if (visuals_matched == 0) {
-/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
-            fprintf(stderr, "default screen depth %d not supported, and no"
-              " 24-bit visuals found\n", depth);
-            return 2;
-        }
-        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
-          visuals_matched))
-        visual = visual_list[0].visual;
-        depth = visual_list[0].depth;
-/*
-        colormap_size = visual_list[0].colormap_size;
-        visual_class = visual->class;
-        visualID = XVisualIDFromVisual(visual);
- */
-        have_nondefault_visual = TRUE;
-        need_colormap = TRUE;
-    } else {
-        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
-        visual = visual_info.visual;
-    }
-
-    RMask = visual->red_mask;
-    GMask = visual->green_mask;
-    BMask = visual->blue_mask;
-
-/* GRR:  add/check 8-bit support */
-    if (depth == 8 || need_colormap) {
-        colormap = XCreateColormap(display, root, visual, AllocNone);
-        if (!colormap) {
-            fprintf(stderr, "XCreateColormap() failed\n");
-            return 2;
-        }
-        have_colormap = TRUE;
-        if (depth == 8)
-            bg_image = FALSE;   /* gradient just wastes palette entries */
-    }
-    if (depth == 15 || depth == 16) {
-        RShift = 15 - rpng2_x_msb(RMask);    /* these are right-shifts */
-        GShift = 15 - rpng2_x_msb(GMask);
-        BShift = 15 - rpng2_x_msb(BMask);
-    } else if (depth > 16) {
-        RShift = rpng2_x_msb(RMask) - 7;     /* these are left-shifts */
-        GShift = rpng2_x_msb(GMask) - 7;
-        BShift = rpng2_x_msb(BMask) - 7;
-    }
-    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
-        fprintf(stderr, "rpng2 internal logic error:  negative X shift(s)!\n");
-        return 2;
-    }
-
-/*---------------------------------------------------------------------------
-    Finally, create the window.
-  ---------------------------------------------------------------------------*/
-
-    attr.backing_store = Always;
-    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
-    attrmask = CWBackingStore | CWEventMask;
-    if (have_nondefault_visual) {
-        attr.colormap = colormap;
-        attr.background_pixel = 0;
-        attr.border_pixel = 1;
-        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
-    }
-
-    window = XCreateWindow(display, root, 0, 0, rpng2_info.width,
-      rpng2_info.height, 0, depth, InputOutput, visual, attrmask, &attr);
-
-    if (window == None) {
-        fprintf(stderr, "XCreateWindow() failed\n");
-        return 2;
-    } else
-        have_window = TRUE;
-
-    if (depth == 8)
-        XSetWindowColormap(display, window, colormap);
-
-    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
-        pWindowName = NULL;
-    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
-        pIconName = NULL;
-
-    /* OK if either hints allocation fails; XSetWMProperties() allows NULLs */
-
-    if ((size_hints = XAllocSizeHints()) != NULL) {
-        /* window will not be resizable */
-        size_hints->flags = PMinSize | PMaxSize;
-        size_hints->min_width = size_hints->max_width = (int)rpng2_info.width;
-        size_hints->min_height = size_hints->max_height =
-          (int)rpng2_info.height;
-    }
-
-    if ((wm_hints = XAllocWMHints()) != NULL) {
-        wm_hints->initial_state = NormalState;
-        wm_hints->input = True;
-     /* wm_hints->icon_pixmap = icon_pixmap; */
-        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
-    }
-
-    if ((class_hints = XAllocClassHint()) != NULL) {
-        class_hints->res_name = res_name;
-        class_hints->res_class = res_class;
-    }
-
-    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
-      size_hints, wm_hints, class_hints);
-
-    /* various properties and hints no longer needed; free memory */
-    if (pWindowName)
-       XFree(pWindowName->value);
-    if (pIconName)
-       XFree(pIconName->value);
-    if (size_hints)
-        XFree(size_hints);
-    if (wm_hints)
-       XFree(wm_hints);
-    if (class_hints)
-       XFree(class_hints);
-
-    XMapWindow(display, window);
-
-    gc = XCreateGC(display, window, 0, &gcvalues);
-    have_gc = TRUE;
-
-/*---------------------------------------------------------------------------
-    Allocate memory for the X- and display-specific version of the image.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        xdata = (uch *)malloc(4*rpng2_info.width*rpng2_info.height);
-        pad = 32;
-    } else if (depth == 16) {
-        xdata = (uch *)malloc(2*rpng2_info.width*rpng2_info.height);
-        pad = 16;
-    } else /* depth == 8 */ {
-        xdata = (uch *)malloc(rpng2_info.width*rpng2_info.height);
-        pad = 8;
-    }
-
-    if (!xdata) {
-        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
-        return 4;
-    }
-
-    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
-      (char *)xdata, rpng2_info.width, rpng2_info.height, pad, 0);
-
-    if (!ximage) {
-        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
-        free(xdata);
-        return 3;
-    }
-
-    /* to avoid testing the byte order every pixel (or doubling the size of
-     * the drawing routine with a giant if-test), we arbitrarily set the byte
-     * order to MSBFirst and let Xlib worry about inverting things on little-
-     * endian machines (e.g., Linux/x86, old VAXen, etc.)--this is not the
-     * most efficient approach (the giant if-test would be better), but in
-     * the interest of clarity, we'll take the easy way out... */
-
-    ximage->byte_order = MSBFirst;
-
-/*---------------------------------------------------------------------------
-    Fill window with the specified background color (default is black) or
-    faked "background image" (but latter is disabled if 8-bit; gradients
-    just waste palette entries).
-  ---------------------------------------------------------------------------*/
-
-    if (bg_image)
-        rpng2_x_load_bg_image();    /* resets bg_image if fails */
-
-    if (!bg_image) {
-        if (depth == 24 || depth == 32) {
-            bg_pixel = (bg_red   << RShift) |
-                       (bg_green << GShift) |
-                       (bg_blue  << BShift);
-        } else if (depth == 16) {
-            bg_pixel = (((bg_red   << 8) >> RShift) & RMask) |
-                       (((bg_green << 8) >> GShift) & GMask) |
-                       (((bg_blue  << 8) >> BShift) & BMask);
-        } else /* depth == 8 */ {
-
-            /* GRR:  add 8-bit support */
-
-        }
-        XSetForeground(display, gc, bg_pixel);
-        XFillRectangle(display, window, gc, 0, 0, rpng2_info.width,
-          rpng2_info.height);
-    }
-
-/*---------------------------------------------------------------------------
-    Wait for first Expose event to do any drawing, then flush and return.
-  ---------------------------------------------------------------------------*/
-
-    do
-        XNextEvent(display, &e);
-    while (e.type != Expose || e.xexpose.count);
-
-    XFlush(display);
-
-    return 0;
-
-} /* end function rpng2_x_create_window() */
-
-
-
-
-
-static int rpng2_x_load_bg_image(void)
-{
-    uch *src;
-    char *dest;
-    uch r1, r2, g1, g2, b1, b2;
-    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
-    int k, hmax, max;
-    int xidx, yidx, yidx_max;
-    int even_odd_vert, even_odd_horiz, even_odd;
-    int invert_gradient2 = (bg[pat].type & 0x08);
-    int invert_column;
-    int ximage_rowbytes = ximage->bytes_per_line;
-    ulg i, row;
-    ulg pixel;
-
-/*---------------------------------------------------------------------------
-    Allocate buffer for fake background image to be used with transparent
-    images; if this fails, revert to plain background color.
-  ---------------------------------------------------------------------------*/
-
-    bg_rowbytes = 3 * rpng2_info.width;
-    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
-    if (!bg_data) {
-        fprintf(stderr, PROGNAME
-          ":  unable to allocate memory for background image\n");
-        bg_image = 0;
-        return 1;
-    }
-
-    bgscale = (pat == 0)? 8 : bgscale_default;
-    yidx_max = bgscale - 1;
-
-/*---------------------------------------------------------------------------
-    Vertical gradients (ramps) in NxN squares, alternating direction and
-    colors (N == bgscale).
-  ---------------------------------------------------------------------------*/
-
-    if ((bg[pat].type & 0x07) == 0) {
-        uch r1_min  = rgb[bg[pat].rgb1_min].r;
-        uch g1_min  = rgb[bg[pat].rgb1_min].g;
-        uch b1_min  = rgb[bg[pat].rgb1_min].b;
-        uch r2_min  = rgb[bg[pat].rgb2_min].r;
-        uch g2_min  = rgb[bg[pat].rgb2_min].g;
-        uch b2_min  = rgb[bg[pat].rgb2_min].b;
-        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
-        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
-        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
-        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
-        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
-        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = (int)(row % bgscale);
-            even_odd_vert = (int)((row / bgscale) & 1);
-
-            r1 = r1_min + (r1_diff * yidx) / yidx_max;
-            g1 = g1_min + (g1_diff * yidx) / yidx_max;
-            b1 = b1_min + (b1_diff * yidx) / yidx_max;
-            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
-            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
-            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
-
-            r2 = r2_min + (r2_diff * yidx) / yidx_max;
-            g2 = g2_min + (g2_diff * yidx) / yidx_max;
-            b2 = b2_min + (b2_diff * yidx) / yidx_max;
-            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
-            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
-            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
-
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                even_odd_horiz = (int)((i / bgscale) & 1);
-                even_odd = even_odd_vert ^ even_odd_horiz;
-                invert_column =
-                  (even_odd_horiz && (bg[pat].type & 0x10));
-                if (even_odd == 0) {        /* gradient #1 */
-                    if (invert_column) {
-                        *dest++ = r1_inv;
-                        *dest++ = g1_inv;
-                        *dest++ = b1_inv;
-                    } else {
-                        *dest++ = r1;
-                        *dest++ = g1;
-                        *dest++ = b1;
-                    }
-                } else {                    /* gradient #2 */
-                    if ((invert_column && invert_gradient2) ||
-                        (!invert_column && !invert_gradient2))
-                    {
-                        *dest++ = r2;       /* not inverted or */
-                        *dest++ = g2;       /*  doubly inverted */
-                        *dest++ = b2;
-                    } else {
-                        *dest++ = r2_inv;
-                        *dest++ = g2_inv;   /* singly inverted */
-                        *dest++ = b2_inv;
-                    }
-                }
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
-    M. Costello.
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 1) {
-
-        hmax = (bgscale-1)/2;   /* half the max weight of a color */
-        max = 2*hmax;           /* the max weight of a color */
-
-        r1 = rgb[bg[pat].rgb1_max].r;
-        g1 = rgb[bg[pat].rgb1_max].g;
-        b1 = rgb[bg[pat].rgb1_max].b;
-        r2 = rgb[bg[pat].rgb2_max].r;
-        g2 = rgb[bg[pat].rgb2_max].g;
-        b2 = rgb[bg[pat].rgb2_max].b;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = (int)(row % bgscale);
-            if (yidx > hmax)
-                yidx = bgscale-1 - yidx;
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                xidx = (int)(i % bgscale);
-                if (xidx > hmax)
-                    xidx = bgscale-1 - xidx;
-                k = xidx + yidx;
-                *dest++ = (k*r1 + (max-k)*r2) / max;
-                *dest++ = (k*g1 + (max-k)*g2) / max;
-                *dest++ = (k*b1 + (max-k)*b2) / max;
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
-    soids will equal bgscale?].  This one is slow but very cool.  Code con-
-    tributed by Pieter S. van der Meulen (originally in Smalltalk).
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 2) {
-        uch ch;
-        int ii, x, y, hw, hh, grayspot;
-        double freq, rotate, saturate, gray, intensity;
-        double angle=0.0, aoffset=0.0, maxDist, dist;
-        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
-
-        fprintf(stderr, "%s:  computing radial background...",
-          PROGNAME);
-        fflush(stderr);
-
-        hh = (int)(rpng2_info.height / 2);
-        hw = (int)(rpng2_info.width / 2);
-
-        /* variables for radial waves:
-         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
-         *   freq:  number of color beams originating from the center
-         *   grayspot:  size of the graying center area (anti-alias)
-         *   rotate:  rotation of the beams as a function of radius
-         *   saturate:  saturation of beams' shape azimuthally
-         */
-        angle = CLIP(angle, 0.0, 360.0);
-        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
-        freq = MAX((double)bg[pat].bg_freq, 0.0);
-        saturate = (double)bg[pat].bg_bsat * 0.1;
-        rotate = (double)bg[pat].bg_brot * 0.1;
-        gray = 0.0;
-        intensity = 0.0;
-        maxDist = (double)((hw*hw) + (hh*hh));
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            y = (int)(row - hh);
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                x = (int)(i - hw);
-                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
-                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
-                gray = MIN(1.0, gray);
-                dist = (double)((x*x) + (y*y)) / maxDist;
-                intensity = cos((angle+(rotate*dist*PI)) * freq) *
-                  gray * saturate;
-                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
-                hue = (angle + PI) * INV_PI_360 + aoffset;
-                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
-                s = MIN(MAX(s,0.0), 1.0);
-                v = MIN(MAX(intensity,0.0), 1.0);
-
-                if (s == 0.0) {
-                    ch = (uch)(v * 255.0);
-                    *dest++ = ch;
-                    *dest++ = ch;
-                    *dest++ = ch;
-                } else {
-                    if ((hue < 0.0) || (hue >= 360.0))
-                        hue -= (((int)(hue / 360.0)) * 360.0);
-                    hue /= 60.0;
-                    ii = (int)hue;
-                    f = hue - (double)ii;
-                    p = (1.0 - s) * v;
-                    q = (1.0 - (s * f)) * v;
-                    t = (1.0 - (s * (1.0 - f))) * v;
-                    if      (ii == 0) { red = v; green = t; blue = p; }
-                    else if (ii == 1) { red = q; green = v; blue = p; }
-                    else if (ii == 2) { red = p; green = v; blue = t; }
-                    else if (ii == 3) { red = p; green = q; blue = v; }
-                    else if (ii == 4) { red = t; green = p; blue = v; }
-                    else if (ii == 5) { red = v; green = p; blue = q; }
-                    *dest++ = (uch)(red * 255.0);
-                    *dest++ = (uch)(green * 255.0);
-                    *dest++ = (uch)(blue * 255.0);
-                }
-            }
-        }
-        fprintf(stderr, "done.\n");
-        fflush(stderr);
-    }
-
-/*---------------------------------------------------------------------------
-    Blast background image to display buffer before beginning PNG decode.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        ulg red, green, blue;
-        int bpp = ximage->bits_per_pixel;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            src = bg_data + row*bg_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (bpp == 32) {    /* slightly optimized version */
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    red   = *src++;
-                    green = *src++;
-                    blue  = *src++;
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            } else {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    red   = *src++;
-                    green = *src++;
-                    blue  = *src++;
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
-                    /*           (probably need to use RShift, RMask, etc.) */
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-        }
-
-    } else if (depth == 16) {
-        ush red, green, blue;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            src = bg_data + row*bg_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                red   = ((ush)(*src) << 8);  ++src;
-                green = ((ush)(*src) << 8);  ++src;
-                blue  = ((ush)(*src) << 8);  ++src;
-                pixel = ((red   >> RShift) & RMask) |
-                        ((green >> GShift) & GMask) |
-                        ((blue  >> BShift) & BMask);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                *dest++ = (char)((pixel >>  8) & 0xff);
-                *dest++ = (char)( pixel        & 0xff);
-            }
-        }
-
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-    XPutImage(display, window, gc, ximage, 0, 0, 0, 0, rpng2_info.width,
-      rpng2_info.height);
-
-    return 0;
-
-} /* end function rpng2_x_load_bg_image() */
-
-
-
-
-
-static void rpng2_x_display_row(ulg row)
-{
-    uch bg_red   = rpng2_info.bg_red;
-    uch bg_green = rpng2_info.bg_green;
-    uch bg_blue  = rpng2_info.bg_blue;
-    uch *src, *src2=NULL;
-    char *dest;
-    uch r, g, b, a;
-    int ximage_rowbytes = ximage->bytes_per_line;
-    ulg i, pixel;
-    static int rows=0, prevpass=(-1);
-    static ulg firstrow;
-
-/*---------------------------------------------------------------------------
-    rows and firstrow simply track how many rows (and which ones) have not
-    yet been displayed; alternatively, we could call XPutImage() for every
-    row and not bother with the records-keeping.
-  ---------------------------------------------------------------------------*/
-
-    Trace((stderr, "beginning rpng2_x_display_row()\n"))
-
-    if (rpng2_info.pass != prevpass) {
-        if (pause_after_pass && rpng2_info.pass > 0) {
-            XEvent e;
-            KeySym k;
-
-            fprintf(stderr,
-              "%s:  end of pass %d of 7; click in image window to continue\n",
-              PROGNAME, prevpass + 1);
-            do
-                XNextEvent(display, &e);
-            while (!QUIT(e,k));
-        }
-        fprintf(stderr, "%s:  pass %d of 7\r", PROGNAME, rpng2_info.pass + 1);
-        fflush(stderr);
-        prevpass = rpng2_info.pass;
-    }
-
-    if (rows == 0)
-        firstrow = row;   /* first row that is not yet displayed */
-
-    ++rows;   /* count of rows received but not yet displayed */
-
-/*---------------------------------------------------------------------------
-    Aside from the use of the rpng2_info struct, the lack of an outer loop
-    (over rows) and moving the XPutImage() call outside the "if (depth)"
-    tests, this routine is identical to rpng_x_display_image() in the non-
-    progressive version of the program.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        ulg red, green, blue;
-        int bpp = ximage->bits_per_pixel;
-
-        src = rpng2_info.image_data + row*rpng2_info.rowbytes;
-        if (bg_image)
-            src2 = bg_data + row*bg_rowbytes;
-        dest = ximage->data + row*ximage_rowbytes;
-        if (rpng2_info.channels == 3) {
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                red   = *src++;
-                green = *src++;
-                blue  = *src++;
-                pixel = (red   << RShift) |
-                        (green << GShift) |
-                        (blue  << BShift);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                if (bpp == 32) {
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                } else {
-                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
-                    /*           (probably need to use RShift, RMask, etc.) */
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-        } else /* if (rpng2_info.channels == 4) */ {
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                a = *src++;
-                if (bg_image) {
-                    bg_red   = *src2++;
-                    bg_green = *src2++;
-                    bg_blue  = *src2++;
-                }
-                if (a == 255) {
-                    red   = r;
-                    green = g;
-                    blue  = b;
-                } else if (a == 0) {
-                    red   = bg_red;
-                    green = bg_green;
-                    blue  = bg_blue;
-                } else {
-                    /* this macro (from png.h) composites the foreground
-                     * and background values and puts the result into the
-                     * first argument */
-                    alpha_composite(red,   r, a, bg_red);
-                    alpha_composite(green, g, a, bg_green);
-                    alpha_composite(blue,  b, a, bg_blue);
-                }
-                pixel = (red   << RShift) |
-                        (green << GShift) |
-                        (blue  << BShift);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                if (bpp == 32) {
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                } else {
-                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
-                    /*           (probably need to use RShift, RMask, etc.) */
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-        }
-
-    } else if (depth == 16) {
-        ush red, green, blue;
-
-        src = rpng2_info.row_pointers[row];
-        if (bg_image)
-            src2 = bg_data + row*bg_rowbytes;
-        dest = ximage->data + row*ximage_rowbytes;
-        if (rpng2_info.channels == 3) {
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                red   = ((ush)(*src) << 8);
-                ++src;
-                green = ((ush)(*src) << 8);
-                ++src;
-                blue  = ((ush)(*src) << 8);
-                ++src;
-                pixel = ((red   >> RShift) & RMask) |
-                        ((green >> GShift) & GMask) |
-                        ((blue  >> BShift) & BMask);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                *dest++ = (char)((pixel >>  8) & 0xff);
-                *dest++ = (char)( pixel        & 0xff);
-            }
-        } else /* if (rpng2_info.channels == 4) */ {
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                a = *src++;
-                if (bg_image) {
-                    bg_red   = *src2++;
-                    bg_green = *src2++;
-                    bg_blue  = *src2++;
-                }
-                if (a == 255) {
-                    red   = ((ush)r << 8);
-                    green = ((ush)g << 8);
-                    blue  = ((ush)b << 8);
-                } else if (a == 0) {
-                    red   = ((ush)bg_red   << 8);
-                    green = ((ush)bg_green << 8);
-                    blue  = ((ush)bg_blue  << 8);
-                } else {
-                    /* this macro (from png.h) composites the foreground
-                     * and background values and puts the result back into
-                     * the first argument (== fg byte here:  safe) */
-                    alpha_composite(r, r, a, bg_red);
-                    alpha_composite(g, g, a, bg_green);
-                    alpha_composite(b, b, a, bg_blue);
-                    red   = ((ush)r << 8);
-                    green = ((ush)g << 8);
-                    blue  = ((ush)b << 8);
-                }
-                pixel = ((red   >> RShift) & RMask) |
-                        ((green >> GShift) & GMask) |
-                        ((blue  >> BShift) & BMask);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                *dest++ = (char)((pixel >>  8) & 0xff);
-                *dest++ = (char)( pixel        & 0xff);
-            }
-        }
-
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-
-/*---------------------------------------------------------------------------
-    Display after every 16 rows or when on one of last two rows.  (Region
-    may include previously displayed lines due to interlacing--i.e., not
-    contiguous.  Also, second-to-last row is final one in interlaced images
-    with odd number of rows.)  For demos, flush (and delay) after every 16th
-    row so "sparse" passes don't go twice as fast.
-  ---------------------------------------------------------------------------*/
-
-    if (demo_timing && (row - firstrow >= 16 || row >= rpng2_info.height-2)) {
-        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
-          (int)firstrow, rpng2_info.width, row - firstrow + 1);
-        XFlush(display);
-        rows = 0;
-        usleep(usleep_duration);
-    } else
-    if (!demo_timing && ((rows & 0xf) == 0 || row >= rpng2_info.height-2)) {
-        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
-          (int)firstrow, rpng2_info.width, row - firstrow + 1);
-        XFlush(display);
-        rows = 0;
-    }
-
-}
-
-
-
-
-
-static void rpng2_x_finish_display(void)
-{
-    Trace((stderr, "beginning rpng2_x_finish_display()\n"))
-
-    /* last row has already been displayed by rpng2_x_display_row(), so we
-     * have nothing to do here except set a flag and let the user know that
-     * the image is done */
-
-    rpng2_info.state = kDone;
-    printf(
-      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
-    fflush(stdout);
-}
-
-
-
-
-
-static void rpng2_x_redisplay_image(ulg startcol, ulg startrow,
-                                    ulg width, ulg height)
-{
-    uch bg_red   = rpng2_info.bg_red;
-    uch bg_green = rpng2_info.bg_green;
-    uch bg_blue  = rpng2_info.bg_blue;
-    uch *src, *src2=NULL;
-    char *dest;
-    uch r, g, b, a;
-    ulg i, row, lastrow = 0;
-    ulg pixel;
-    int ximage_rowbytes = ximage->bytes_per_line;
-
-
-    Trace((stderr, "beginning display loop (image_channels == %d)\n",
-      rpng2_info.channels))
-    Trace((stderr, "   (width = %ld, rowbytes = %d, ximage_rowbytes = %d)\n",
-      rpng2_info.width, rpng2_info.rowbytes, ximage_rowbytes))
-    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
-    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
-      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
-
-/*---------------------------------------------------------------------------
-    Aside from the use of the rpng2_info struct and of src2 (for background
-    image), this routine is identical to rpng_x_display_image() in the non-
-    progressive version of the program--for the simple reason that redisplay
-    of the image against a new background happens after the image is fully
-    decoded and therefore is, by definition, non-progressive.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        ulg red, green, blue;
-        int bpp = ximage->bits_per_pixel;
-
-        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
-            src = rpng2_info.image_data + row*rpng2_info.rowbytes;
-            if (bg_image)
-                src2 = bg_data + row*bg_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (rpng2_info.channels == 3) {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    red   = *src++;
-                    green = *src++;
-                    blue  = *src++;
-#ifdef NO_24BIT_MASKS
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    if (bpp == 32) {
-                        *dest++ = (char)((pixel >> 24) & 0xff);
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    } else {
-                        /* this assumes bpp == 24 & bits are packed low */
-                        /* (probably need to use RShift, RMask, etc.) */
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    }
-#else
-                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
-                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
-                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
-                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    if (bpp == 32) {
-                        *dest++ = (char)((pixel >> 24) & 0xff);
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    } else {
-                        /* GRR BUG */
-                        /* this assumes bpp == 24 & bits are packed low */
-                        /* (probably need to use RShift/RMask/etc. here, too) */
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    }
-#endif
-                }
-
-            } else /* if (rpng2_info.channels == 4) */ {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    r = *src++;
-                    g = *src++;
-                    b = *src++;
-                    a = *src++;
-                    if (bg_image) {
-                        bg_red   = *src2++;
-                        bg_green = *src2++;
-                        bg_blue  = *src2++;
-                    }
-                    if (a == 255) {
-                        red   = r;
-                        green = g;
-                        blue  = b;
-                    } else if (a == 0) {
-                        red   = bg_red;
-                        green = bg_green;
-                        blue  = bg_blue;
-                    } else {
-                        /* this macro (from png.h) composites the foreground
-                         * and background values and puts the result into the
-                         * first argument */
-                        alpha_composite(red,   r, a, bg_red);
-                        alpha_composite(green, g, a, bg_green);
-                        alpha_composite(blue,  b, a, bg_blue);
-                    }
-#ifdef NO_24BIT_MASKS
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    if (bpp == 32) {
-                        *dest++ = (char)((pixel >> 24) & 0xff);
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    } else {
-                        /* this assumes bpp == 24 & bits are packed low */
-                        /* (probably need to use RShift, RMask, etc.) */
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    }
-#else
-                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
-                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
-                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
-                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    if (bpp == 32) {
-                        *dest++ = (char)((pixel >> 24) & 0xff);
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    } else {
-                        /* GRR BUG */
-                        /* this assumes bpp == 24 & bits are packed low */
-                        /* (probably need to use RShift/RMask/etc. here, too) */
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    }
-#endif
-                }
-            }
-            /* display after every 16 lines */
-            if (((row+1) & 0xf) == 0) {
-                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-                  (int)lastrow, rpng2_info.width, 16);
-                XFlush(display);
-                lastrow = row + 1;
-            }
-        }
-
-    } else if (depth == 16) {
-        ush red, green, blue;
-
-        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
-            src = rpng2_info.row_pointers[row];
-            if (bg_image)
-                src2 = bg_data + row*bg_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (rpng2_info.channels == 3) {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    red   = ((ush)(*src) << 8);
-                    ++src;
-                    green = ((ush)(*src) << 8);
-                    ++src;
-                    blue  = ((ush)(*src) << 8);
-                    ++src;
-                    pixel = ((red   >> RShift) & RMask) |
-                            ((green >> GShift) & GMask) |
-                            ((blue  >> BShift) & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            } else /* if (rpng2_info.channels == 4) */ {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    r = *src++;
-                    g = *src++;
-                    b = *src++;
-                    a = *src++;
-                    if (bg_image) {
-                        bg_red   = *src2++;
-                        bg_green = *src2++;
-                        bg_blue  = *src2++;
-                    }
-                    if (a == 255) {
-                        red   = ((ush)r << 8);
-                        green = ((ush)g << 8);
-                        blue  = ((ush)b << 8);
-                    } else if (a == 0) {
-                        red   = ((ush)bg_red   << 8);
-                        green = ((ush)bg_green << 8);
-                        blue  = ((ush)bg_blue  << 8);
-                    } else {
-                        /* this macro (from png.h) composites the foreground
-                         * and background values and puts the result back into
-                         * the first argument (== fg byte here:  safe) */
-                        alpha_composite(r, r, a, bg_red);
-                        alpha_composite(g, g, a, bg_green);
-                        alpha_composite(b, b, a, bg_blue);
-                        red   = ((ush)r << 8);
-                        green = ((ush)g << 8);
-                        blue  = ((ush)b << 8);
-                    }
-                    pixel = ((red   >> RShift) & RMask) |
-                            ((green >> GShift) & GMask) |
-                            ((blue  >> BShift) & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-            /* display after every 16 lines */
-            if (((row+1) & 0xf) == 0) {
-                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-                  (int)lastrow, rpng2_info.width, 16);
-                XFlush(display);
-                lastrow = row + 1;
-            }
-        }
-
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-    Trace((stderr, "calling final XPutImage()\n"))
-    if (lastrow < startrow+height) {
-        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-          (int)lastrow, rpng2_info.width, rpng2_info.height-lastrow);
-        XFlush(display);
-    }
-
-} /* end function rpng2_x_redisplay_image() */
-
-
-
-
-
-#ifdef FEATURE_LOOP
-
-static void rpng2_x_reload_bg_image(void)
-{
-    char *dest;
-    uch r1, r2, g1, g2, b1, b2;
-    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
-    int k, hmax, max;
-    int xidx, yidx, yidx_max;
-    int even_odd_vert, even_odd_horiz, even_odd;
-    int invert_gradient2 = (bg[pat].type & 0x08);
-    int invert_column;
-    ulg i, row;
-
-
-    bgscale = (pat == 0)? 8 : bgscale_default;
-    yidx_max = bgscale - 1;
-
-/*---------------------------------------------------------------------------
-    Vertical gradients (ramps) in NxN squares, alternating direction and
-    colors (N == bgscale).
-  ---------------------------------------------------------------------------*/
-
-    if ((bg[pat].type & 0x07) == 0) {
-        uch r1_min  = rgb[bg[pat].rgb1_min].r;
-        uch g1_min  = rgb[bg[pat].rgb1_min].g;
-        uch b1_min  = rgb[bg[pat].rgb1_min].b;
-        uch r2_min  = rgb[bg[pat].rgb2_min].r;
-        uch g2_min  = rgb[bg[pat].rgb2_min].g;
-        uch b2_min  = rgb[bg[pat].rgb2_min].b;
-        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
-        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
-        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
-        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
-        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
-        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = (int)(row % bgscale);
-            even_odd_vert = (int)((row / bgscale) & 1);
-
-            r1 = r1_min + (r1_diff * yidx) / yidx_max;
-            g1 = g1_min + (g1_diff * yidx) / yidx_max;
-            b1 = b1_min + (b1_diff * yidx) / yidx_max;
-            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
-            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
-            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
-
-            r2 = r2_min + (r2_diff * yidx) / yidx_max;
-            g2 = g2_min + (g2_diff * yidx) / yidx_max;
-            b2 = b2_min + (b2_diff * yidx) / yidx_max;
-            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
-            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
-            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
-
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                even_odd_horiz = (int)((i / bgscale) & 1);
-                even_odd = even_odd_vert ^ even_odd_horiz;
-                invert_column =
-                  (even_odd_horiz && (bg[pat].type & 0x10));
-                if (even_odd == 0) {        /* gradient #1 */
-                    if (invert_column) {
-                        *dest++ = r1_inv;
-                        *dest++ = g1_inv;
-                        *dest++ = b1_inv;
-                    } else {
-                        *dest++ = r1;
-                        *dest++ = g1;
-                        *dest++ = b1;
-                    }
-                } else {                    /* gradient #2 */
-                    if ((invert_column && invert_gradient2) ||
-                        (!invert_column && !invert_gradient2))
-                    {
-                        *dest++ = r2;       /* not inverted or */
-                        *dest++ = g2;       /*  doubly inverted */
-                        *dest++ = b2;
-                    } else {
-                        *dest++ = r2_inv;
-                        *dest++ = g2_inv;   /* singly inverted */
-                        *dest++ = b2_inv;
-                    }
-                }
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
-    M. Costello.
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 1) {
-
-        hmax = (bgscale-1)/2;   /* half the max weight of a color */
-        max = 2*hmax;           /* the max weight of a color */
-
-        r1 = rgb[bg[pat].rgb1_max].r;
-        g1 = rgb[bg[pat].rgb1_max].g;
-        b1 = rgb[bg[pat].rgb1_max].b;
-        r2 = rgb[bg[pat].rgb2_max].r;
-        g2 = rgb[bg[pat].rgb2_max].g;
-        b2 = rgb[bg[pat].rgb2_max].b;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = (int)(row % bgscale);
-            if (yidx > hmax)
-                yidx = bgscale-1 - yidx;
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                xidx = (int)(i % bgscale);
-                if (xidx > hmax)
-                    xidx = bgscale-1 - xidx;
-                k = xidx + yidx;
-                *dest++ = (k*r1 + (max-k)*r2) / max;
-                *dest++ = (k*g1 + (max-k)*g2) / max;
-                *dest++ = (k*b1 + (max-k)*b2) / max;
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
-    soids will equal bgscale?].  This one is slow but very cool.  Code con-
-    tributed by Pieter S. van der Meulen (originally in Smalltalk).
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 2) {
-        uch ch;
-        int ii, x, y, hw, hh, grayspot;
-        double freq, rotate, saturate, gray, intensity;
-        double angle=0.0, aoffset=0.0, maxDist, dist;
-        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
-
-        hh = (int)(rpng2_info.height / 2);
-        hw = (int)(rpng2_info.width / 2);
-
-        /* variables for radial waves:
-         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
-         *   freq:  number of color beams originating from the center
-         *   grayspot:  size of the graying center area (anti-alias)
-         *   rotate:  rotation of the beams as a function of radius
-         *   saturate:  saturation of beams' shape azimuthally
-         */
-        angle = CLIP(angle, 0.0, 360.0);
-        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
-        freq = MAX((double)bg[pat].bg_freq, 0.0);
-        saturate = (double)bg[pat].bg_bsat * 0.1;
-        rotate = (double)bg[pat].bg_brot * 0.1;
-        gray = 0.0;
-        intensity = 0.0;
-        maxDist = (double)((hw*hw) + (hh*hh));
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            y = (int)(row - hh);
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                x = (int)(i - hw);
-                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
-                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
-                gray = MIN(1.0, gray);
-                dist = (double)((x*x) + (y*y)) / maxDist;
-                intensity = cos((angle+(rotate*dist*PI)) * freq) *
-                  gray * saturate;
-                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
-                hue = (angle + PI) * INV_PI_360 + aoffset;
-                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
-                s = MIN(MAX(s,0.0), 1.0);
-                v = MIN(MAX(intensity,0.0), 1.0);
-
-                if (s == 0.0) {
-                    ch = (uch)(v * 255.0);
-                    *dest++ = ch;
-                    *dest++ = ch;
-                    *dest++ = ch;
-                } else {
-                    if ((hue < 0.0) || (hue >= 360.0))
-                        hue -= (((int)(hue / 360.0)) * 360.0);
-                    hue /= 60.0;
-                    ii = (int)hue;
-                    f = hue - (double)ii;
-                    p = (1.0 - s) * v;
-                    q = (1.0 - (s * f)) * v;
-                    t = (1.0 - (s * (1.0 - f))) * v;
-                    if      (ii == 0) { red = v; green = t; blue = p; }
-                    else if (ii == 1) { red = q; green = v; blue = p; }
-                    else if (ii == 2) { red = p; green = v; blue = t; }
-                    else if (ii == 3) { red = p; green = q; blue = v; }
-                    else if (ii == 4) { red = t; green = p; blue = v; }
-                    else if (ii == 5) { red = v; green = p; blue = q; }
-                    *dest++ = (uch)(red * 255.0);
-                    *dest++ = (uch)(green * 255.0);
-                    *dest++ = (uch)(blue * 255.0);
-                }
-            }
-        }
-    }
-
-} /* end function rpng2_x_reload_bg_image() */
-
-
-
-
-
-static int is_number(char *p)
-{
-    while (*p) {
-        if (!isdigit(*p))
-            return FALSE;
-        ++p;
-    }
-    return TRUE;
-}
-
-#endif /* FEATURE_LOOP */
-
-
-
-
-
-static void rpng2_x_cleanup(void)
-{
-    if (bg_image && bg_data) {
-        free(bg_data);
-        bg_data = NULL;
-    }
-
-    if (rpng2_info.image_data) {
-        free(rpng2_info.image_data);
-        rpng2_info.image_data = NULL;
-    }
-
-    if (rpng2_info.row_pointers) {
-        free(rpng2_info.row_pointers);
-        rpng2_info.row_pointers = NULL;
-    }
-
-    if (ximage) {
-        if (ximage->data) {
-            free(ximage->data);           /* we allocated it, so we free it */
-            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
-        }
-        XDestroyImage(ximage);
-        ximage = NULL;
-    }
-
-    if (have_gc)
-        XFreeGC(display, gc);
-
-    if (have_window)
-        XDestroyWindow(display, window);
-
-    if (have_colormap)
-        XFreeColormap(display, colormap);
-
-    if (have_nondefault_visual)
-        XFree(visual_list);
-}
-
-
-
-
-
-static int rpng2_x_msb(ulg u32val)
-{
-    int i;
-
-    for (i = 31;  i >= 0;  --i) {
-        if (u32val & 0x80000000L)
-            break;
-        u32val <<= 1;
-    }
-    return i;
-}
diff --git a/extern/libpng/include/contrib/gregbook/toucan.png b/extern/libpng/include/contrib/gregbook/toucan.png
deleted file mode 100644
index 03960d4939938541ca3f8efee4bf13ffdecbb2f5..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 12901
zcma*NWpo@(vMt(@TFlH07Be$5GlRv<%*<@D#mr!V#mp>=(Xz$NEcMklbI#m(>%AXu
zud1#cJ2EmWGkdMBijHVyMJYr$JU9RVfG8s^uKIZ``aIKNAOHX`!oF1CrvbDSQ4j%u
zMHH|cr5gbN5CCO)b%{^?{|#6GI1B*%zje6(GU5NlRXmX=`N0_(A%xV>KIS3t$)QLv
zQPAKaY!jf6!6DFKA+BP;aS(tXOVE|;Uwp<0CBPx<gdhY=ASnbPaj_s&5?~~tAV{$x
z?!SYd{AT5&W8qaq0s{bkCqss(un;4lvcf_(Mj(IQ10fvj(>ek%2QX+9N}6AR78ggv
z7y<(tDDvfVZh(LUC<bE)7P^08xm_SQ82=GfJ%LDw{}4J(IQKEc^f9RWNoW`_fRPIn
z5jg}J7!Vs8ic=lJegKLF4<d~doQ4I$A_3Wm34#C%^4K1nUkmNCH!v^&9z4WDA2<pG
z1OfsCHu67f_=!)~f8*aRKNaMEEeq6t`N{sJ-~qr<0FeLo{&(PiIO6A4{0s2^75gb5
z{Y(Gci~qFz4?zHcA^dODf5cA$|NkZarvc3Wvwsvw@XtAZ9-sL4q@<yMpX9k0{NLuk
z_5bislb8x<Ywpd(hR7EJ0R|4>aDtRFhN+r_B0_*rDFZ%cgL7s9GZxYKaNytiAy8o<
zK4ankJ;1+)_%uHc3<!wNDPhAwzD+@J5PxY|MikG0d@ci5uR|t-hxoY&En<qn?|}B%
zzfcgIBo9JdcnUE&3@Y3|>!1etPoK|Y|FdGB%Ksn01O8|4J{$jgBVYkwFaQWRFz_wD
zcdvi$%1u>K4FFaS4p9LFfgquvVL)(YupoHQKUfBRfZqSbKFR+@Ea>gi5dR<H15^qE
zEtr5n{Gc*~f3&gxae)36bgiB7X}i5D7C7>;(-VdVC4xLbxrnJC%1@d03#v_sPy`DI
z#TlfBgvIoM42mg1!!%U~fzbW3@x?JfxW%NBWH@-~(jYE^qPPz?TWuREkU7XeRz^L5
z)zI>vp=|&8_%|jKPuzGs^^^~C_x@J`fdc-aA1WYukOQ_TO;%<;MIbQ=x!`vn5GPw2
zDEZULr+>x^0FVG=#6{G-*3W$5xfh>5grL|M$^WKI4*jfQiPuZU9gHbtfkr=&WwSL%
zv5i1cx)_WYB{v`4mr;p<qg0P+hN4`MfaXxov7_E{`?2(E?H1%G)v|teaCZFt_El)M
z=NFEV(WSTlcH8Xh`$t!=s%l_JNR86QFVjTX+1>~|&T`^d9t;6jdFSmVAcQM70jBuR
z?DCrr)rN21M1F^DwpOHf(0Mmq*4qpki|KZmt3(dweY4NV@07ejk{o^Dj1K4fcG!3)
zmiU_>G75d9f^4;3ONXdK8*Syu3Oq-&Fs{+WHBQPe)5^eBia)QXHevUq^>0j=YYxq1
zB+txJ=r8k!mYI=D>GaJw4tvu-T~01;PbspQHcxpxJu_VUW+NH;R(d179U8i_FNCbA
zwTha**o3-x!OATw-r&eCuV9z{C@*n8#^%rlbXQfCAf#?XG)O8QO22baFPc2fG>~X|
zd~hg+BxsqcH*37}8-u?KBY`s-bLaVS8kzFrX8E&GN<CbDM-Re~ku}U;rP%!D!~aL;
zq7yTUx01}z@mCnh^GffTWbB-+-Bc9%mDsA${h!E7<DB|DW{V$dVCP1t6yP-+?WJ_O
zmyK~7Eg$EJhmRY}0?^oqQVyOtxF*a~m;0@0>^6>mDhQ10CbQ3L<H`F;(NSX04XkZE
z8#d(Q+}^!@w+y0B)LOE#0W(ORg1p*hxbIce-+Ru7BNMeYO<wUl_~kk29M#^TZIcy)
zD`odX_s5kSlha=uQwFb&e+@3jm8||2`UwkbS>xi=&_;aGYt|XqdtN;~3<tl1Q(fr%
zjeDYTzR`j?Wu_BjYKT2zpQ)LIV%Atz{%{vp(NPvpNj+j;U?-;@_&Ti+FgK~g@aLPL
zWmeo&|H4y9^W-C5eb~?QtV91AMH>6;Z*~)4-@L|zt7WFJnPXDgMrr8A21>xD4=rh$
zx`f?YYcTI(hX3>x!gd7Bzll48xv8_uIG!QIPa7CH@SCu)u$W9qWmWB{dV;-)lU;gy
zrZ~1WzKNTO9kl4yIfN7!cOx6JS>3&o@MfSeR}o<2s$6g5b~aL{=3Thj#yPk%H&T%k
zMei>yxv*|<cGJIO1yYj_Rt<BAT3^hdvU&i;1WaSP!zup)!MBFOfG-+Zk(Kpi$XySh
z-Jx{u=f{w*3pTU36XQ!BrtxOq{hU}8_j?O~az&4$!8_w4gg=EG?H4D@Gg(;^kul@!
zqmbQm-{*-jC#4+56w^U&_dKKUMa3sJs?A1bE8R0fC`A221eeXTfv@F0VH({&nybo%
z6s1Z0N#zufLk3>_41?~8XXWyxJEjpdU9Ytvo!J9{E6bqAMJ|57^@09uM(LNqjWbvT
z=vO{Z`o4IWFz~a-5L!6QqXIU&K;9!WpZ#muwl3C|aK~E3-!<A2<&n>kGZ^AhQkMD-
zNVB@qHx)LBh%*!J=)fRmn(Md1ij+BYU#uIq!iaudTOu^1NOBc$-e6LMS-%EXuu?gO
zOO8z476;7!Q)fx5+da3Z(6O%^&*3B|=+Q5DhO92EIW?TE&H6}N&MUQ|`=)W~N5d8q
zeZo`dV`JR*KInu?DgHw(6|6s=R?OM@9kyZPjJBuxf^aGV4I3B)NA54~PWJ?oeO+TU
z0{6K^)5-3oX|(o{5Umk8vaAb^um_P!DySz0jftfY9h<A#no8T+q&NB4*(sNqn94U8
ze`?aGZnSW4b#444*w(q8`<CU57Wg1B0q!DMEWy6XL4btcsYy>|BQH<!t+&fd%|965
z`Xo1m?F0;GYY5g9B|Kr>Z>4u};|3qQZ&8o^Qu2Et)yj?hmk6_-CjWtv)m5?}1ryI;
z&^H#i94EsMvA(`WXZqyIvH9nNpGf%$l`VZgv`n88sQFF55!H0Cc~3rg(wXkcGw_{_
zt;m$MVBwIOexEax%UEk}WVC6%5bw}av9fyUw9l{+f9MLhh%5Jj&KmEsm);H3icisL
z+BH8OoOg#*(ZqFs^_+<Y#8Mh@9h)2<XV;wl@o;YU7z1L!NJAF#U6^+@R^gAu`C-#M
zYgf@E@D6kfDpFP7-Ydhx!Zx~e7K`FlacXgPlwGQ(_<vDzv)79(XTpo*NEu9#+UrZ0
z!X6XoY10wW6{K7{zppQ{JULG0-`mSvab{)R;C)G71pl$`I2M4kOk3M5z<M|sZ+YfZ
zvF^eu_q}0t>l!;V2TmCV!|!p*b~q6ndvDZ!*IIy8@s%}mJCUoS%mJZR9PUZ3C~-fq
zNGyCRYe}(mtu>VkSwi7p?PUWz@tDaz?rliToGWq!+wLxr-p|QvBv5N2^h&_+2R>4|
zSwNGJj3cu3rVx(~Wp#6DW4pX2&+z+)@SO;q-lLMB9wnKp<y!hz>&kC;6Z%QCvUGyd
zE!hf*uX~bfZv;Btn7@zV%#}1K^HDQ&bktgdP6xNgWpzIc&LS#DXeMRfB|v;|trpze
z+7MrXq_F-Vi#&&2W9OHI_p1hh)qt~e1~(j;kQ<w!XQ37)UrN}?Ua}*U8bbQBbESN!
zvxwT%iDW~x6Q(H@jc@N-Pai>lT)9V(bPqf)j<iF~zM1T6dV5yeo_5;_7v9&F$2>$z
zh+EL~V@);)wPv${r7UT@SP;d1+<~o}_4oHzha%+wy6OGz4$ceX(s@_LQ_XE+*{_tj
zzY;3hmCedgXs;rJ5L%^xZy81b(eV;PqG5~A8<n+@v7&ZLg3~%?2Wm(wbC(<>ND9{+
znpdmTKs1^HJ!GU-vo_A1TKW3%II9ZohSLBC=bn?VYBVL1=&QKCq~EIRCxQ^MOA4-4
zeyrWs#@9`2y+J3eb%aat*UPFrBZ%EW)7V5IHb?0ySbF1~QoQwTcNMxB`MKSZR)@qj
zr>9I7O6k9U`NfuRLGux8qwmyq03Q48TZB$MnE2Pmo`|4J>K|qsf2ADZi*&y>sTtH`
zgcG#o1~}93vpG(tHbJIM7d27<mK=qX6=WC`8Jfpy+B_$MtWa<&>Ss~Y;g1~`RAcQ1
z6(#w-bz8cbg=P#SG<0NSRAf|4L}K-42a-$7B^L25OH5?LeQ$2^$bIi;6>;V7W6HC^
zhxv2z!)0W!V+Y7@533S}kAfHDw_#;9tA4Q6qLcl^RqBN;suUJJMVm-Hx?4NAn+}g{
zK1BV_n@+Yc<PpQ)n2-P*B|*sT)ig2!)nxs&W^iU0BeDaEim19xEjL*5+{EsB{ar^C
zmZ!~GoM!#9O@bD^@;#J_eHl$l!HJ55l~Yl;5ZEaPe<I)zynZxD9AmW@9y{)Vj#qh@
z-Odv~z%Rv$JcmE}w5@IwlhKfEYGo&eZ2aRo8$*FpVvmpWz}{L0vJ$)0|K59EltAZ*
zh=6Jgb>o90byI|G;J4EXf`D85l{mgB{$JR?;=aC&dGU{>4TNic0e#d01+hgdP$wU^
zcY>MpA`HFEkY|R($Fb`U3ko-P6v;l)B&MWU#?}HjYHFt@j1l-jxWj*IYd8E?i@&Li
zuJ`y`*M5O|v*qA;eOV9Xl1eA^%6t5?x|M{D+)6jQq9c{#!+>Qkeoo@)=61w-{#{{o
zDLyWaUqHb3ZG;eF=Et*v9T@mM;TWHXqmS#Z=v!MLs1s?!oU_wi%JzLfUPXmcii$i2
z^RSRY<=lz9%yw)mPf{o=rE|XQ<fNm+L;eb^&H3ks?VFp(rbxk)+Zb-f*|sts^2uae
zh*jKVG1oOVoNkkWl6ud2D#uPgBBaMEn}CpWy_!Ntyn|_oU%XqR8S9J{LFh4@@giK3
zGzFo0Aq)@C@6BuLM<n7v)B{a#Zg)<bzx%{*<+phbvo2cc`ApLEFZ%cowl%Z3`5fHI
z(K|}3t;vGzoUB>V5LtNCI?n}F3ev)`DlT%IL!%hof=Ts7HQBvf?PV^;fC9Pa#k0m4
z0iVD6JFX>pIW9sid^x`xJhs-2!$YYE)mfh|Af?_y#0ONCv@-Yw)gAR%v=I6+)Zxfe
zZ^`l)`sT|+Evh{0%F9P#Nx%uxO&oo_e8;&7f%pLQL*M|?8y~QWU|4E`ATAMhE#-dO
zv1C7O%XKpi8wN|e%3$_I&7MpsirDxL&C$B@qIq{CBz-L%!J=!)?yu0~t|*vMpQlgO
z{1cg~IZ?$9ECKiM=G6f^lViao;%gCOYinJ(*QGB`Z{xkge&b-gQ1gq@N(g%zlkold
zww4RGYv&)!zlj-sCgSsUZ)KxQ#NF@n?mm;Z(CO=S*u_On(5(5ARFO(rioF-u6!R;m
z-aPhEGlI)Wpl2^IHJ;xGynN_tJ3b}X;$CSnMY7kacWUnLdbU;S-xfV2FQU5wd;42C
zPIfQsOI7$bC)9<ADfVyke<~2wdnbKAKEP_!!h{kmt|=S47gtDYYQ~T^R8bM>7hpYG
zlz*F)g1k>t`XksYBS%+CP{Ey4RI}IPda1}Urf)*4ftq2cwHG+%W>VFu7;#qNxYZ%#
znlV8}R^QxJlmadtQ)<$5Sp!yvk&#x+JBwX{>H46_@7-EGXMp<f<rnMmPBzq?bL^(o
zM^Wz)hz>k0t|X6?c_I}m6lCDQh%|_Wq<qi9kD$G9?1%C7YG>E7pZnbDaOSEZ{Qa1(
zpd{GG8=M>bx!l=@<!G4~NT@vfy~h<=bX*z@E(u1QgH@a8p`OpHH>oF~R*YmSO~1S_
zC6>fb%f*}0tdeFNWXn=PyvU3&vtEjXB%Bab+Rd>=w`srb0lNO1)_R<wDCp%OWb|xA
z^EXU7Nr1{J>YzMWFhYs%Zbe=RE7wLoP2KrX)$=J*zBeGHnyS|-{Vs5h2MHbhaC(}d
z=J@WzX`^$x5?gM86-h$OjheicqVrnZXUH&3!jtBABkcDuSR^r{z%;QGjZ#o@KeGGo
z<U(XY6OD9E?W2+-wYolqw1{0zJQPVl!LxUc`)T?Y6aqIlz-kFa$Mmy^J)JV;^zssy
z*1?vRL5YX5Q(?r1PUFXkN?mujI}ZU4!W;Herzkqu7w(@SqPG`~4SSmsuHsH!3bv8U
z0mCeZwGlT`745O&!2=PBUyNbm3JSF9*>1@=wf31jmag{sS=3!?W%c`i35#roAw>4~
zWct=gq_&#udL!parJql4W&NpZmY((^WuJ;bi12}!p7~Oz%OYv4Z{X5!C%P`7Y#7pX
zFEKqH6=7-KPUBn!7t0|XjOZ98{XHA)^p;(+yWnKWdXT(2E4EMy&+{keYd%b{&Dq}A
zxwCBk?o<CeDxQKa6qMS_3*L7?A96_=;O|CUb36kB1Lcp5AD0|?H~HTK()81AN5_R<
zxh{9WqQt~QX|8n;6N=+D^<{gHRo*s^;3I2Ti#S{L>#7~?dh~Qs{XobY82wh~kBrlN
ze84+V1R&<?k$!xG{oth3b)QyI5Mjh}+l3Vrcy8UAD(0h<0s!mWe_3{g%a)Y{JW1iD
z%UzUr5#aR<b<-95h?nzzsTd-?t9i@IM)th+07;0y#i_;hr(nQ9SJTii{nz3mJO@~F
z_LLW%sL29aL3+yB@<9=bUYk}HD&j01Sz*tphp_<sM6&pg(62(3x17cm1$c*bQ#>0b
zr5x<+928i$UIrogsj|q!-?QbBXXWa+odPX26FTu0A(YisRrR^gd{PSbeX5OI!4S4w
zk<|?j*uhK*7P7N#SbrTl_c11YTh`9fX>8-(G0>0^F~p+ckx5EV|H$P>JeTQ2O!f5W
zA!T5=G`uHqjm4HSs^KtW=D?ulv|U*F4G#n#K-$<lw?Qcx)^=mA-q2}GTwkj_BEOOJ
zjqSQ$=C~f3tAZF-P_yU)78dZ+ygGQ9Z5APKi&LC%txwHV+0L-z)ut}<<dFzg3oR}3
zm15%H{9K;W*3KKUEQv5nZ)f8DnyS6ME@vQKgP*%?<a?Cx6$R>r<eNw?MxXPR_`qyP
zNeOkI%L*C!1I$dxbQ7Y$@|wRweR@#kFf$4PLtal0t~OipSXL&pB0V;hw?rvX?3jk(
zqF}t_-#IJP@kF28rBH~WJJc)hAu6_OT{35e#aHH5)B@o9>jECg!}V?X>oS9N>0FQQ
zrQg9OM@6bAg$Jws@^zH$7w*#o9~#c+f|*Seqb7|lRsU_3q#r*<FHOWB8~n72+c#aU
zTw`ePLs^!@WD}~sP;EQQ3l|=R_MDt>t)&MrGP-)KUYvK|RYU60s1i{L<gH9iJ8HYk
z)*QD-vkW^iEIGbV3D+bLLE6Q~$D@Zza*VFoDJVQ-mX?)9*~pX@Nu<kdZ1n0X*X2>9
z?5aBC9OH!hMVLkH7Rd-49Hc)r7NaY>TKqY30*7EWwf(b}ZSWg0L&4gSxLA4hyc!mv
zHMXW};7c7h>z`=z;s$N1U*&^)*$#X&Yja7})v@x-f;JFXXU6t;b4!vYe>pnY36I|x
z!Hi=^ZJWSk2CvqgX~LgrdwCR>Oije)+2Ix5@#HQFk{hRHY$tzqAYly*4Ux!akc*8%
z%<ikMV#uQGcNUO*JR<OulLW;c{?JHUYVr`+L7P`j2RXywnW*Sc%o3qR53y3lYWK`E
zb6$9z6Z%R5pa%PX6S|-IE3BQ7#F);NiDBnJD;ndNhWhg|BGV#$6Ho{+$9HLCeY2jC
z+NSuL<z}iNkl7}mSyrZ9%!wxBDIjU(=vXCn2rqSQ0E8#$6fYrKwI#xwT3&kRmL`dN
zcY+*}Z95*PyLVrUPtAH1I+1ByuRE<fz7FM8wQaz$jPa~3-O-nuII;lb680hf`6!9i
zUPcbTiM+<%4$yn?tPg4=KJD9{%QiquYizub)!vhORY*jxn~vPv`t{5IVzZr%JWsNX
zmv_vJiUgg&mJ&Y{w4dK1O%YhfaDzjkT3Wgjz_;xVc4ndisR?PFajFz1;GRD_9~F0R
zH(1AFa?k9(A-OKK{>E>k&}il|nti(BY+KQ0vm0dtd?(fdo1|2P<~omUo%no*-)ni9
zZ@YG^EwV_|&kAemd9EHYIiI<EO8WdlS;Xr<zQOwbiafJ)Q(K9Q1;bnVb*}-fqx6+b
zf8g5K+HHM!k&sW9Y36Qt)F_I!^0B@q+N+1|u=uWA0Xz1*2gxY3I1ksP1uV0}!|cqy
zI7gp9K!8d(D5Mzp`69a%t?Y<w$IS<2H#krxrhlqi6oBBKTVq{8JEiix>eCQJzErP}
z7+uU-kDry@itDT}Zgz%OoSzgzl3UQ;szU|`tC}`C&!YE>JTFZ{Al?bzNx-G#S=&pZ
z5N_35&;!qr3iq^sXx;q@Jl)d4^sFv%tTu9wy9n_Ho#|&7Ibrxw>Y8Tuyv;_#mVu5=
z?US|P%N`)<cO9gMo#Uao{i^dX*R7RCd3JY1+%Z4{ICB<7l(~>-Ql_+2e=<VWR-#2~
z#HB`BT6(&M+idL^ystB?(;Ison{`=&eaE4s4?_2z{Ja%9Yq||EOI8m$3z$m{vkL=6
z3;r_*Hkv+|#YZWdl&&$c_R3FIZ*mFF21z&*(BfmJnV5{-EM2#QONGS+qZ5Oj9tXks
z6Mw>SS5(A(r!~@AZ_st85|gSvyNRx;M*ChZ&bETRn=_sC_(31*z+ASq<VB?YSDC`P
z8DDuQQwHqsC2EW&{=Q@LkuIzZc6k-bFH+{gEJ#MI3iX|lvK-&}ICcJnS>xYA5j~!7
zz+Z>95r=MK1&J5-92TeZ3%b?cJl9{4GQcLlhi$U4*St8lbI?cqP1(Zd>^6Jx;j`ax
zBeid(n5O%%*FAC|1;2iO^fTLuc*^WV4TlSyGxPZ(oj!W|ckPt&@K2}QUwGE5^rC*m
zQq2rK1HB)5oHLwA^kM_g;DW3Gm>czJ#{JogNO|<f!`C0hG;IYx%8ycBmS0$sABv?k
z-KR%sq4iG#opKSx3co)4y*w)B)Tr7&{tV<qHh!qqSlx~dsJUo9cYd2n7(bR(P?48x
zUb1ubu_)7v>IIo;_W~FJ^Dg6GCJi(BjjNK6YjH~xxza9vOb~g!o4Mv!P`6MP4{>zw
z3QOeamD+0q;b?H)VE;DzCQqhoc7SYb<=ptC;{xq!<+t-%y8qlaE~lhuZhQ%UZuh-0
zH0QKKc+s<wJa!mwqT3WQYNsg?4-1<K8v1!J{li`?Jw;Vt!$SIG|HX7%M|MJ|la_YE
zh1>{xSX^kk73{>Q+^;8*?$j{3r{!Kf%6@+<_%4DTGPBEfj}qitn~L1$3)xchji99_
z2Agl;!G5)&eh9QjmOZ^N;mbxRR(6Zmx>(Y?p2~#0aQJO+;^1InkN(O~Q$$6?u#%gM
zV&lZb+HXAV>Qy%Xup;y3&E4y!ZeTNpVO-<lMj5}2{!KedFT4aAfs(h07TTtD#0;Zk
zt1~C-)jL78$>uR%VA5Snb-E+a$fW{CSP;2BxjA>oze05R;I6jvp6{YVU|d)H1wqYC
zX<St;Xq>jHVoD>iiFPCZyfWMK23~DDkHEtAH2vAH{N$^uK_)o0VnG?l;%lz0VD+A*
zzdB&N3QJ0G2R$pNzU!x({!3dpr1IEkumm2jh`W}`3)^&s(1jsr>G&=7pC@;w7xZ#G
z|3ReXWgvL)j4?`0<ZB419sqyw!{SI=TN^<vbQ~?^4baDWBqK_Za@`w-clO6v0O9IL
zSc<%y)XbF~fpn3SIVB|p2oAO=Z;1e6GVb6;IePHC5RTM9T26t;_*H%>4TF~lK|)G;
zBccI|GD3!Ob=%)dsQH1cn$Ka-*Ee^JVC)JENl4h^he0a=GP7?&yE!1jqK1csx*%S|
z19T9v^E6c;tz+rWggSS9??Wfx6N+wm{%D*FX8=ekgkyQ|n<D|>*QhBe1cjl@)mJ<r
zitJ=5T)q<NTRX6<dgej5LKHK~71&9}2q$)h5SB4k4qm!s%t6lD;Iknp7<-rj<M!(h
zpNV#r`Q2K*oE)WG-lZ;gI=3WrmrYIqdVbf*)Uobi9*`#E!)p&}n5eLnE2q>Ks&qX+
zb7KdGo|}YsX0RA0q~*Jho^0&aQK+}Jj@Gj6$sQawJyy2Vhdc{e*{_TiD{UQyJS^7u
z9<0x6+ZZiO$W2N?6$uKz<tca(n4s&!H2z>((2WGirarxE?mDEAeoV*Tudz_#7qiwB
z761LabLM+@L|Pz~_;9{~O$_3EQ5I3xo!me3(E=qMYw6`398}Qy>BMP;15DgQBA}#1
zIo%R^dNQqg7J}!6{Lkthp7*5^Mb+M<GMJ1U$O~_SprE1U<cI~=AE}7&vgpU6LXaTD
z^m3F|m&N(F@`~w^UsF&ZuTECAKf)rQlx~J~I8Az7?A+L$zX9l-ahjxUB~yf>!U%9k
zqghj=LxtyYi#e+aKRDqr2z{71Ftf2BC+eare&&PBhmR<O2CMDay}Eu_{OPNtYFyL8
zqPxt@splmI3OL@t6ENadhl>@UM4i|G$zWfw;Opz^B*~J0)8@~4+69)@)}G(p#WrYV
zAwQ^Nb_D9!VvwMMGUtBh+OuYop|wP*1<!=QHsVq!%JcYLoZVS^@u+GuVq6^qZEXqd
z3-)^Y`#V$CmKw6JQZ@ZEdm_HfKAu&2VR;wOwq42bwP1q>>(}+8b6MkB;mX$<;8Pn0
zV>2Ee-+J-4q8J)7qEJw>;Ala=5{(#*t!jgRrg%DBz6!gjdLA#Gc11CaE71a)UfcQL
z)tX%XEUFi*K1p<!8VMg>%^+Fhq97tflx1fRef9SzvdmQgC;xr&yC5#C;9z~wtGXg9
zlQ(GYUi}smg#HCelqykcW}Jo1QSRo}653-Q%W}Aqnr19;H<_9{AA&F+7e`pCqYrHs
z{Mp)Rna4+Db??9eDi<&$rL0t5N<meIr0n5gWo706o-8@e?>^tR7eMWC=pVh>jqw<r
z2PXPnX($~bUZl+roy3NE1@@Wax#&k^BJS~qM>K<&0AOHZLK4bkOc~a}cSBRq@suj`
zerx~C24D9&1$^i&l%?nkt~~{%`;x+<6=q$ORhIn#6p!$}G=1=Z&A1DK4Jk0m6>=jM
z{SFt?oNELK!+_O<M!b?nCHX5xc1JLG(1B!lbpL#Je8(b7DGt=!gqJ~00&}jYgiRq=
z8iev1Z+d(xFgzLbPcZ<79c7_Wqipjn@LGQRknn^SO*n6BQ3yo!_)LQq?H<<+42xns
zLj}?gpjzTRugt*8yTtK>>9@D76pR;Sz_iEq&&{n<`Hval4BX_W;s8kc9<LPKL>3X6
zF?ZzbH=W@o@DoIk2sLkM-^{4Ko$yO<BZMdp|0qv3_w}@BXVRRXVMoh;-Ys{OCZFMQ
z>UVuIzJZgSn3#xxyZLVD@9gNvbd^pDX!Mk(Qzoz~Ll&Lk6^sg%k(opS*J6~8ZC~*@
zX`n#qFn|-vf^Mo8P=?urCp^H$E-NwHKO7R-ySS(;>v#&AN|hj+ce<olQ^XVT^yuh1
zwWO)u$G+Iq`M$s1TlHAu1%pQ9l?6WV9nKC8s0vK>ZC6%C`k04xWV1L`+NyPfpY?5M
z|8pE{@Ysf3zBf9J2u&?QUJiG2bJKJS(|VLCX5QE#lS_{+Z9`<${1}g);tZYH)#STd
zSFVJI_aN@muVsB48|g!eiEkwW0k5k|!VC^xrHBCoIdDTkx<%(Zx^;X7J?jx%Q4WR3
z0Fb{dNBo$Mk}_%3w!)i~Ff5$iP+DA*frpAS4{Z_Pr_Yj?lS4+f@76}bsPru-2^0I>
zBEwJNz-k*3LBgIOI_MNaQE=YBIQYsW!QY9j@ZEn`MguN(XrOSupJ!bi{ZKJmt|7Lx
z?Z=O{F?<xfq<n|78yXhmC%4q)Ib}ztRlNxCoFU<ruZ?Rl?jvvc;iAF9FwEP0m?;5G
zg=cc*(8`pNRLK?Fi^le4`y7YHaA{PyfS|nFpYt*<56fmSJw{8mP<F^ecr1X`4Pd;#
zyn+H`ok7FTFV3H}L{I<J0#twgNt&vS<QIW7?#$W3Lm}Yms<DebUGds%(7cvzWmz?r
zQcZIM-*`3@Kj*W~+|rWZBjVFhrtc7BiZ&o=M{;mo5Gg$)8|PF-<8;2L8!BuC{8Ql!
zPAp3fl!-g4SX-<mb@29m2pCsSf+ENkFZSMc_=TZUG-^dgoOnu~UC6sMG!!;I^x|?K
zf|F2jB95dYNAEoa3FB%b3lH~)j{DMr#10Kjg&IuxamjyPg{3y~amC8^u@Z7;F90`6
zxN-&HzVJPm&;z`$=3;|<i`~@;QeU*#nOo=t?@S3KojJ!0(NN~If~J)jJxu3yc|9F(
zJvS+`8&f34rpC5b7wC&x<G|x0_b@qjJwh;qzvA=ecdyCEGz^T-`hGg%Zpapia5K`P
zXlaRh*D%e!1%*ej>$FVR(wLR0G%_-01}O^zq&eDo|2eylkDZ}MbkgRq^+x3tOcgzb
zOLpmqwIeitcYohla(@T#f8-9$6eDEYujBDVdWs`$d&u9(c`;^A@WD}w+ZK9`Mj0z6
z&cl8Qn$sqe<fa{Kgs-oxl(8<SZ_!_mu#6Qis+S;PR+eCNP3B#N1V)#V%`cRinwoAi
z#)gj#u;lt`=LshX1QeB$S>pL1?06hZ;S!v$PcR}t6^~-ZC;1>Cip<+N{8R;|dG`qc
zv}O9apixC}f+C3=zP>iCVJN_b$6Kn6^kq<GfJ?JO&BauZS<Wx8B=0}r<k%06)Dxvn
zo%adu9A4jvr)mpO)FAN*9}NyA<b3V1d2BpAIx0x1t92V{aHeO^hC;#fiAy{kcoyCo
zNxEK}f?dG*7T|fuoB(DZXa`VAT_`&aT`7428h3Q8f?;q*prXu46k54(1lL;CS=28R
z*diPAc_4Ne!`NXbfmc+C@|6q_JFLi4WlMb3&CYaTv6rWXS=?5qT|ydwNm?_>q*6D|
zh=?F+p`PMSqJfi8Y6!MtVj=BMo-wkppKTyMeEAKrn)GyKdd3I`HMqR@>-mo4n`u(e
z?9srF>*9ppD_#%OzUq<FOY=~jEg>mYzD~{;br8wP=AEtOLzT220VMZBtU5jVaA_O^
zA!DgPg=_t`TT;)Y`DWA_CQb3vv%6n<juT6WO@j8$QswYb@=U_Bs8P_f!@n5Z&KUeR
z{FniQHk`tumo5ljPZ2DH!4^0Ly6f|mMiZ@h7mnZN3&dMF_;6_Jn^a?5tMfR-yXu^M
z!DyGe_Qp2-(sukgmq+o1$u{DBe``z5x!UCY9!^~{Y0HzbNQvt>r?+O$?x>?7>Ar+5
zC!}9KHDTUll=4wl7RJt*H0IMqKlAtV`w7^z$_Of|Y}=N*iPP?%8h(+~S{WhUgL+07
zIJspM`uT!<mX8E+Y&Vq7fa+b(RC-B#<>&#KRSMd3^STKZZP^(-Vsr7Gj;fo*!<tNt
zyPr3>{2M#GzP6UNTqNIU<h%Y{ATuNA({bv)l9<>Qt69f>qXxZ^R7~C`#}tLcUlLm@
z<vH}1rlq)8#OXx{@;!yu_Aw&kbz2m@UPVPy6T9agPk+|kEb;vbwBEj+S++pm6(=fJ
zC@eQ3Z-y_*c5eR$mZi{9IgZj*C@QN!V;C0?i-(=mDxB6dtWAy4;TJZgT-6MuQ&tv)
zLm-t<$*y&yOj1W7{UA}Giq(l%5yrv5XU@$PxGarJRYCY6#<@0h3oQ%7|HyMFuyc9d
z$(MZ=r0(hQP)Tz-qa2v;SW;kYcCe|esh82(&i*wrXb;U4hYMXO78R((k2`v>%iWH^
z!5JZ!+tjH37;J@$zqJ5CcLfDJGf82PGo>Wr?eFj;Q%UopnpXtD#=IkRP&D)fR{<w)
ztWhTMT@2pb&ay@mdx49}%t236kR5Mu75z8xe*VSC`K8o`Em0l?EUqr!=}5ZHLUA(K
zBufT_645)U^!1NZzo<U!4*uoO`(-%JJ4`8k#4Qql3Afu>?`@ZrTF5J2u8d<wr#Wn_
zzggF+%<wC<Q`M|7Nuc~|?~W0F2BGieWLt%l2XR<UkECD32kB_7<$l3&SuVT4@o>8$
z7|V=dAM?Pz?r)gxtUuh_<K86jZF0rk^a#YMjlC~KKSsZ1{yLWb>jK-{Ermi*s63YH
zOoPFjCR)xcE6Z9@)$WPnt2rmhN^1$;bxi9c@JQ6_=l$Z=2nqn7vlO=7;lftqEU>b7
zP`y;QAKt~$3fdMRwQyyrbjoWZ*_-lZTib@b_G^8w>6^xC_zs9hXLyZy@4f?i94Vhg
z`!<fL<rfws7P5UgcjNubx}Gxe)A_HG9=jyfeT{aE@9p$2^Y|s@nY}%J4vjAvxPFkB
zu+lflki2<@Mj3R?=MxFo45cSggj-0j#-*|V9N4_LY5%XI+<&_k)f1co^v}|ov^_{N
z&xe_5u)m`O!+YC#yj89aX=|RX{lJYLt*>BZWtEj3qhtgoyA&>jk`(1$%ouJxvqG!0
z;rmd(r(?L^U<Awv-*`p{R#aVvcsSNg2J@R1#63xeLVM=BCA9wxQW=Y;`mQ=hfh=5x
zHsGDb#fSBmw_h2uKgA9#Aq?fF%kc9-rvYeb)Shz9*4LX}QKwotI{(#ARcU@B?6X#O
zrA|k$;I5j<zLAC_264}th?k%u_pQJIvl$=Li)m8otFf-n6!^?Ql0WQs#pBf>AY)oU
zys`^7JnJTs5R};PJSWaN88C?;PdnmaDM=a!1zoNcbpbaG+hGcl94!OhJ%Vrc24f;U
zn_Ar}JZzz$!0y;;Y1zJn{$^u+&i~oNmc|vEiS2g>$XR~m>#$2Zjz>~vW)L}pVN~0O
zkWxHP3etDfsNc>^j;A<NGN|%o_sp~CR;jD=CS_Vx>TZj0=K3X?K7z4btqW^>3qpOp
zTOSwMqH{g(q$a2*3+opi_FD%d5&FH04&iWLu~Dw?Oh>ut`A!!_rZ|$ly<Au?g2E_{
z5^=&VAxV+HAad}|bwtNa3ChInR%UJXN%8T{{dPIRpj{6rF?wS24(z>(JY0I)s2wqK
zs4lnwlPS|!tHWJv_E^z8kB}JPNDm0hMdTqBB*hvX9_C3Egx|)B7T~n+-zWR51WFF~
zykOM&Gvu7d%$jn>t}qXVw-0sCx)1l4)<ELj841Jw`cUZ$vM1uYO@IV?5-#3M4UIi3
zo*tf!hepJExRY}N0XkqnK8m4|<*UbnM=vvp8g%ZEjOR--6Zp&wc*1$<FvRF2#LSw@
zdj1vq(bJAP+~1QOTHLBw^)zV049BVBvYU>Uvd1>q<OyqP<WPD$t$5wpOuB<i5?_;)
zcc$5Sb<Zg?<9e1p+$5@Je!-6lzIS1>y|xNZ2tzL7cugWy?lA5^(SCVm2*j-lF52V@
z+T%x*`0$QnzCi=sQ)sQE))$@5i!5n_%E;WVC-CQKJ}4QyFA?w54K&f~&R7^d6jIU6
zPj`1xfXC^L*Jscf-{V`m$+~`0;&)~W=mb49C_HNA&mUfMHzy)W1G*D==8R-$N%7Zr
zbF6;+e6*#WbR$n3w-0m&PQ^MyQ7YqO`kFbBryEFO%AgS@5>jnOMe3u_t_d?%4X*TH
z{5+BTylYAX%v=|+#TsxTno;spmmLhP@5DYGb;_LLVILP@C>fFS;v)~!tu~=`PTn(w
z@kq2sccr}peszs_a|jf~@0}a(6)VWFA|VbDn}oBIbW&_Bdy?$OI#a2_7$wSqVNMW8
zQ7moec)LT|o}Km&ELgd(qU71jCs@!EQ?R)buGTAc`(&6qv-!Bwc!oQ3r~BS{UR<7w
zzki8DO>^bD?$zuVE?6~FS0Elv9U$D^?!mf^V8)z$rNjVY<Ergxa#z~C8&<4`*1c=F
z)9>%ID;{EdFzTiE1K=;e9Qk<?4tmEtSmd;9{Kew`eW;$OnB(4&+(Y`SD4?Z%S$iX{
zNMifNM>gXl#UrL)nNm{m6wV0io`SMJnp7jViK_}}T?)OW`2<^`_|QGc(qUi8*gRgx
z{-!?xiX#<PMWk}R905W)-@B~$<z=LxMHZvK#=3z<t0n0axs^62t=gT2#}h&5&I9Y-
zFUQT^yuG3CH_o=#4$p@cj@ZDdedtYVaG~q3U$av48WI@iKP;XBjc}s=(pEn!3dMem
zb5ROivfc6J?K5y_Nr+rYuuNP1&?U{U3K`Wt>CoA7{3v@;VAO`^mfBIAxo(5^u@`?-
z)!O(Kd=k9Yde7M2WlPxo!YWbUs9DH}eX_B<*m^qYN+4D&rZb3)BF-KJ&P71fPk}$O
zJEdAJIYUf+tAU{x<D#`);C5(|^X6Xb!(_EdOvOseG_Hm<dAk?0@|lC=h!<tbSg~HQ
zfiN|F!gRN{HJG@nt*KcXR)}YC(!y@vtv%ofYt6>4?>CGnbMGE@jD1gHO+dQh(lR=O
z91<c)iJMrW9HyMkt`%WGTVh}9FzVJlW&Y6LO~Emu>6my<lCe%xwteIEIfsW;!#4^R
z;hpF+o9;ROko<KI4QGz-ioD6iLrPM6A|Z###*cwZtY%=Op#eeM3gYLF=qUBQPZ4bd
zwnQ93Oaaf!S#mmBZf;D_wc}vnQlZ_mFR<KK^WrYY#iQA)Y8`lGWkju;=ZwtGuINlq
z?-g1&@w2G{lW@EiD)3Ant3-Qc6b;wYIBzKReSbAc6wED6dv1L^UJ9nnqGF<=Vq$fO
zVL=9lVKG)YvMv|RyLM;eD#CAVw7bqR5}ECc9`aIv*ztH!;GPlD3qUPENJxJlsj)B5
f6#07~#Se&Sk-?3tS&oo@%Ijq$6vgXAjYIwqf?o_r

diff --git a/extern/libpng/include/contrib/gregbook/wpng.c b/extern/libpng/include/contrib/gregbook/wpng.c
deleted file mode 100644
index a06e3529ec..0000000000
--- a/extern/libpng/include/contrib/gregbook/wpng.c
+++ /dev/null
@@ -1,853 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   wpng - simple PNG-writing program                                 wpng.c
-
-   This program converts certain NetPBM binary files (grayscale and RGB,
-   maxval = 255) to PNG.  Non-interlaced PNGs are written progressively;
-   interlaced PNGs are read and written in one memory-intensive blast.
-
-   Thanks to Jean-loup Gailly for providing the necessary trick to read
-   interactive text from the keyboard while stdin is redirected.  Thanks
-   to Cosmin Truta for Cygwin fixes.
-
-   NOTE:  includes provisional support for PNM type "8" (portable alphamap)
-          images, presumed to be a 32-bit interleaved RGBA format; no pro-
-          vision for possible interleaved grayscale+alpha (16-bit) format.
-          THIS IS UNLIKELY TO BECOME AN OFFICIAL NETPBM ALPHA FORMAT!
-
-   to do:
-    - delete output file if quit before calling any writepng routines
-    - process backspace with -text option under DOS/Win? (currently get ^H)
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.01:  initial public release
-    - 1.02:  modified to allow abbreviated options
-    - 1.03:  removed extraneous character from usage screen; fixed bug in
-              command-line parsing
-    - 1.04:  fixed DOS/OS2/Win32 detection, including partial Cygwin fix
-              (see http://home.att.net/~perlspinr/diffs/GregBook_cygwin.diff)
-    - 2.00:  dual-licensed (added GNU GPL)
-
-        [REPORTED BUG (win32 only):  "contrib/gregbook/wpng.c - cmd line
-         dose not work!  In order to do something useful I needed to redirect
-         both input and output, with cygwin and with bcc32 as well.  Under
-         Linux, the same wpng appears to work fine.  I don't know what is
-         the problem."]
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "wpng"
-#define VERSION   "2.00 of 2 June 2007"
-#define APPNAME   "Simple PGM/PPM/PAM to PNG Converter"
-
-#if defined(__MSDOS__) || defined(__OS2__)
-#  define DOS_OS2_W32
-#elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
-#  ifndef __GNUC__   /* treat Win32 native ports of gcc as Unix environments */
-#    define DOS_OS2_W32
-#  endif
-#endif
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <setjmp.h>     /* for jmpbuf declaration in writepng.h */
-#include <time.h>
-
-#ifdef DOS_OS2_W32
-#  include <io.h>       /* for isatty(), setmode() prototypes */
-#  include <fcntl.h>    /* O_BINARY for fdopen() without text translation */
-#  ifdef __EMX__
-#    ifndef getch
-#      define getch() _read_kbd(0, 1, 0)    /* need getche() */
-#    endif
-#  else /* !__EMX__ */
-#    ifdef __GO32__
-#      include <pc.h>
-#      define getch() getkey()  /* GRR:  need getche() */
-#    else
-#      include <conio.h>        /* for getche() console input */
-#    endif
-#  endif /* ?__EMX__ */
-#  define FGETS(buf,len,stream)  dos_kbd_gets(buf,len)
-#else
-#  include <unistd.h>           /* for isatty() prototype */
-#  define FGETS fgets
-#endif
-
-/* #define DEBUG  :  this enables the Trace() macros */
-
-/* #define FORBID_LATIN1_CTRL  :  this requires the user to re-enter any
-   text that includes control characters discouraged by the PNG spec; text
-   that includes an escape character (27) must be re-entered regardless */
-
-#include "writepng.h"   /* typedefs, common macros, writepng prototypes */
-
-
-
-/* local prototypes */
-
-static int  wpng_isvalid_latin1(uch *p, int len);
-static void wpng_cleanup(void);
-
-#ifdef DOS_OS2_W32
-   static char *dos_kbd_gets(char *buf, int len);
-#endif
-
-
-
-static mainprog_info wpng_info;   /* lone global */
-
-
-
-int main(int argc, char **argv)
-{
-#ifndef DOS_OS2_W32
-    FILE *keybd;
-#endif
-#ifdef sgi
-    FILE *tmpfile;      /* or we could just use keybd, since no overlap */
-    char tmpline[80];
-#endif
-    char *inname = NULL, outname[256];
-    char *p, pnmchar, pnmline[256];
-    char *bgstr, *textbuf = NULL;
-    ulg rowbytes;
-    int rc, len = 0;
-    int error = 0;
-    int text = FALSE;
-    int maxval;
-    double LUT_exponent;                /* just the lookup table */
-    double CRT_exponent = 2.2;          /* just the monitor */
-    double default_display_exponent;    /* whole display system */
-    double default_gamma = 0.0;
-
-
-    wpng_info.infile = NULL;
-    wpng_info.outfile = NULL;
-    wpng_info.image_data = NULL;
-    wpng_info.row_pointers = NULL;
-    wpng_info.filter = FALSE;
-    wpng_info.interlaced = FALSE;
-    wpng_info.have_bg = FALSE;
-    wpng_info.have_time = FALSE;
-    wpng_info.have_text = 0;
-    wpng_info.gamma = 0.0;
-
-
-    /* First get the default value for our display-system exponent, i.e.,
-     * the product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  If the PNM image
-     * looks correct on the user's display system, its file gamma is the
-     * inverse of this value.  (Note that this is not an exhaustive list
-     * of LUT values--e.g., OpenStep has a lot of weird ones--but it should
-     * cover 99% of the current possibilities.  This section must ensure
-     * that default_display_exponent is positive.) */
-
-#if defined(NeXT)
-    /* third-party utilities can modify the default LUT exponent */
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to
-     * get the "gamma" value, so we do it the hard way */
-    tmpfile = fopen("/etc/config/system.glGammaVal", "r");
-    if (tmpfile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, tmpfile);
-        fclose(tmpfile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL) {
-        double exponent = atof(p);
-
-        if (exponent > 0.0)
-            default_gamma = 1.0 / exponent;
-    }
-
-    if (default_gamma == 0.0)
-        default_gamma = 1.0 / default_display_exponent;
-
-
-    /* Now parse the command line for options and the PNM filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-i", 2)) {
-            wpng_info.interlaced = TRUE;
-        } else if (!strncmp(*argv, "-time", 3)) {
-            wpng_info.modtime = time(NULL);
-            wpng_info.have_time = TRUE;
-        } else if (!strncmp(*argv, "-text", 3)) {
-            text = TRUE;
-        } else if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                wpng_info.gamma = atof(*argv);
-                if (wpng_info.gamma <= 0.0)
-                    ++error;
-                else if (wpng_info.gamma > 1.01)
-                    fprintf(stderr, PROGNAME
-                      " warning:  file gammas are usually less than 1.0\n");
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else {
-                    unsigned r, g, b;  /* this way quiets compiler warnings */
-
-                    sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-                    wpng_info.bg_red   = (uch)r;
-                    wpng_info.bg_green = (uch)g;
-                    wpng_info.bg_blue  = (uch)b;
-                    wpng_info.have_bg = TRUE;
-                }
-            }
-        } else {
-            if (**argv != '-') {
-                inname = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-
-    /* open the input and output files, or register an error and abort */
-
-    if (!inname) {
-        if (isatty(0)) {
-            fprintf(stderr, PROGNAME
-              ":  must give input filename or provide image data via stdin\n");
-            ++error;
-        } else {
-#ifdef DOS_OS2_W32
-            /* some buggy C libraries require BOTH setmode() and fdopen(bin) */
-            setmode(fileno(stdin), O_BINARY);
-            setmode(fileno(stdout), O_BINARY);
-#endif
-            if ((wpng_info.infile = fdopen(fileno(stdin), "rb")) == NULL) {
-                fprintf(stderr, PROGNAME
-                  ":  unable to reopen stdin in binary mode\n");
-                ++error;
-            } else
-            if ((wpng_info.outfile = fdopen(fileno(stdout), "wb")) == NULL) {
-                fprintf(stderr, PROGNAME
-                  ":  unable to reopen stdout in binary mode\n");
-                fclose(wpng_info.infile);
-                ++error;
-            } else
-                wpng_info.filter = TRUE;
-        }
-    } else if ((len = strlen(inname)) > 250) {
-        fprintf(stderr, PROGNAME ":  input filename is too long [%d chars]\n",
-          len);
-        ++error;
-    } else if (!(wpng_info.infile = fopen(inname, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open input file [%s]\n", inname);
-        ++error;
-    }
-
-    if (!error) {
-        fgets(pnmline, 256, wpng_info.infile);
-        if (pnmline[0] != 'P' || ((pnmchar = pnmline[1]) != '5' &&
-            pnmchar != '6' && pnmchar != '8'))
-        {
-            fprintf(stderr, PROGNAME
-              ":  input file [%s] is not a binary PGM, PPM or PAM file\n",
-              inname);
-            ++error;
-        } else {
-            wpng_info.pnmtype = (int)(pnmchar - '0');
-            if (wpng_info.pnmtype != 8)
-                wpng_info.have_bg = FALSE;  /* no need for bg if opaque */
-            do {
-                fgets(pnmline, 256, wpng_info.infile);  /* lose any comments */
-            } while (pnmline[0] == '#');
-            sscanf(pnmline, "%ld %ld", &wpng_info.width, &wpng_info.height);
-            do {
-                fgets(pnmline, 256, wpng_info.infile);  /* more comment lines */
-            } while (pnmline[0] == '#');
-            sscanf(pnmline, "%d", &maxval);
-            if (wpng_info.width <= 0L || wpng_info.height <= 0L ||
-                maxval != 255)
-            {
-                fprintf(stderr, PROGNAME
-                  ":  only positive width/height, maxval == 255 allowed \n");
-                ++error;
-            }
-            wpng_info.sample_depth = 8;  /* <==> maxval 255 */
-
-            if (!wpng_info.filter) {
-                /* make outname from inname */
-                if ((p = strrchr(inname, '.')) == NULL ||
-                    (p - inname) != (len - 4))
-                {
-                    strcpy(outname, inname);
-                    strcpy(outname+len, ".png");
-                } else {
-                    len -= 4;
-                    strncpy(outname, inname, len);
-                    strcpy(outname+len, ".png");
-                }
-                /* check if outname already exists; if not, open */
-                if ((wpng_info.outfile = fopen(outname, "rb")) != NULL) {
-                    fprintf(stderr, PROGNAME ":  output file exists [%s]\n",
-                      outname);
-                    fclose(wpng_info.outfile);
-                    ++error;
-                } else if (!(wpng_info.outfile = fopen(outname, "wb"))) {
-                    fprintf(stderr, PROGNAME ":  can't open output file [%s]\n",
-                      outname);
-                    ++error;
-                }
-            }
-        }
-        if (error) {
-            fclose(wpng_info.infile);
-            wpng_info.infile = NULL;
-            if (wpng_info.filter) {
-                fclose(wpng_info.outfile);
-                wpng_info.outfile = NULL;
-            }
-        }
-    }
-
-
-    /* if we had any errors, print usage and die horrible death...arrr! */
-
-    if (error) {
-        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, APPNAME);
-        writepng_version_info();
-        fprintf(stderr, "\n"
-"Usage:  %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] pnmfile\n"
-"or: ... | %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] | ...\n"
-         "    exp \ttransfer-function exponent (``gamma'') of the image in\n"
-         "\t\t  floating-point format (e.g., ``%.5f''); if image looks\n"
-         "\t\t  correct on given display system, image gamma is equal to\n"
-         "\t\t  inverse of display-system exponent, i.e., 1 / (LUT * CRT)\n"
-         "\t\t  (where LUT = lookup-table exponent and CRT = CRT exponent;\n"
-         "\t\t  first varies, second is usually 2.2, all are positive)\n"
-         "    bg  \tdesired background color for alpha-channel images, in\n"
-         "\t\t  7-character hex RGB format (e.g., ``#ff7700'' for orange:\n"
-         "\t\t  same as HTML colors)\n"
-         "    -text\tprompt interactively for text info (tEXt chunks)\n"
-         "    -time\tinclude a tIME chunk (last modification time)\n"
-         "    -interlace\twrite interlaced PNG image\n"
-         "\n"
-"pnmfile or stdin must be a binary PGM (`P5'), PPM (`P6') or (extremely\n"
-"unofficial and unsupported!) PAM (`P8') file.  Currently it is required\n"
-"to have maxval == 255 (i.e., no scaling).  If pnmfile is specified, it\n"
-"is converted to the corresponding PNG file with the same base name but a\n"
-"``.png'' extension; files read from stdin are converted and sent to stdout.\n"
-"The conversion is progressive (low memory usage) unless interlacing is\n"
-"requested; in that case the whole image will be buffered in memory and\n"
-"written in one call.\n"
-         "\n", PROGNAME, PROGNAME, default_gamma);
-        exit(1);
-    }
-
-
-    /* prepare the text buffers for libpng's use; note that even though
-     * PNG's png_text struct includes a length field, we don't have to fill
-     * it out */
-
-    if (text &&
-#ifndef DOS_OS2_W32
-        (keybd = fdopen(fileno(stderr), "r")) != NULL &&
-#endif
-        (textbuf = (char *)malloc((5 + 9)*75)) != NULL)
-    {
-        int i, valid, result;
-
-        fprintf(stderr,
-          "Enter text info (no more than 72 characters per line);\n");
-        fprintf(stderr, "to skip a field, hit the <Enter> key.\n");
-        /* note:  just <Enter> leaves len == 1 */
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_TITLE_OFFSET;
-            fprintf(stderr, "  Title: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.title = p;
-                wpng_info.have_text |= TEXT_TITLE;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_TITLE;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_TITLE;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_AUTHOR_OFFSET;
-            fprintf(stderr, "  Author: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.author = p;
-                wpng_info.have_text |= TEXT_AUTHOR;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_AUTHOR;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_AUTHOR;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_DESC_OFFSET;
-            fprintf(stderr, "  Description (up to 9 lines):\n");
-            for (i = 1;  i < 10;  ++i) {
-                fprintf(stderr, "    [%d] ", i);
-                fflush(stderr);
-                if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1)
-                    p += len;   /* now points at NULL; char before is newline */
-                else
-                    break;
-            }
-            if ((len = p - (textbuf + TEXT_DESC_OFFSET)) > 1) {
-                if (p[-1] == '\n') {
-                    p[-1] = '\0';
-                    --len;
-                }
-                wpng_info.desc = textbuf + TEXT_DESC_OFFSET;
-                wpng_info.have_text |= TEXT_DESC;
-                p = textbuf + TEXT_DESC_OFFSET;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_DESC;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_DESC;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_COPY_OFFSET;
-            fprintf(stderr, "  Copyright: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.copyright = p;
-                wpng_info.have_text |= TEXT_COPY;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_COPY;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_COPY;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_EMAIL_OFFSET;
-            fprintf(stderr, "  E-mail: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.email = p;
-                wpng_info.have_text |= TEXT_EMAIL;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_EMAIL;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_EMAIL;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_URL_OFFSET;
-            fprintf(stderr, "  URL: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.url = p;
-                wpng_info.have_text |= TEXT_URL;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_URL;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_URL;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-#ifndef DOS_OS2_W32
-        fclose(keybd);
-#endif
-
-    } else if (text) {
-        fprintf(stderr, PROGNAME ":  unable to allocate memory for text\n");
-        text = FALSE;
-        wpng_info.have_text = 0;
-    }
-
-
-    /* allocate libpng stuff, initialize transformations, write pre-IDAT data */
-
-    if ((rc = writepng_init(&wpng_info)) != 0) {
-        switch (rc) {
-            case 2:
-                fprintf(stderr, PROGNAME
-                  ":  libpng initialization problem (longjmp)\n");
-                break;
-            case 4:
-                fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                break;
-            case 11:
-                fprintf(stderr, PROGNAME
-                  ":  internal logic error (unexpected PNM type)\n");
-                break;
-            default:
-                fprintf(stderr, PROGNAME
-                  ":  unknown writepng_init() error\n");
-                break;
-        }
-        exit(rc);
-    }
-
-
-    /* free textbuf, since it's a completely local variable and all text info
-     * has just been written to the PNG file */
-
-    if (text && textbuf) {
-        free(textbuf);
-        textbuf = NULL;
-    }
-
-
-    /* calculate rowbytes on basis of image type; note that this becomes much
-     * more complicated if we choose to support PBM type, ASCII PNM types, or
-     * 16-bit-per-sample binary data [currently not an official NetPBM type] */
-
-    if (wpng_info.pnmtype == 5)
-        rowbytes = wpng_info.width;
-    else if (wpng_info.pnmtype == 6)
-        rowbytes = wpng_info.width * 3;
-    else /* if (wpng_info.pnmtype == 8) */
-        rowbytes = wpng_info.width * 4;
-
-
-    /* read and write the image, either in its entirety (if writing interlaced
-     * PNG) or row by row (if non-interlaced) */
-
-    fprintf(stderr, "Encoding image data...\n");
-    fflush(stderr);
-
-    if (wpng_info.interlaced) {
-        long i;
-        ulg bytes;
-        ulg image_bytes = rowbytes * wpng_info.height;   /* overflow? */
-
-        wpng_info.image_data = (uch *)malloc(image_bytes);
-        wpng_info.row_pointers = (uch **)malloc(wpng_info.height*sizeof(uch *));
-        if (wpng_info.image_data == NULL || wpng_info.row_pointers == NULL) {
-            fprintf(stderr, PROGNAME ":  insufficient memory for image data\n");
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(5);
-        }
-        for (i = 0;  i < wpng_info.height;  ++i)
-            wpng_info.row_pointers[i] = wpng_info.image_data + i*rowbytes;
-        bytes = fread(wpng_info.image_data, 1, image_bytes, wpng_info.infile);
-        if (bytes != image_bytes) {
-            fprintf(stderr, PROGNAME ":  expected %lu bytes, got %lu bytes\n",
-              image_bytes, bytes);
-            fprintf(stderr, "  (continuing anyway)\n");
-        }
-        if (writepng_encode_image(&wpng_info) != 0) {
-            fprintf(stderr, PROGNAME
-              ":  libpng problem (longjmp) while writing image data\n");
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(2);
-        }
-
-    } else /* not interlaced:  write progressively (row by row) */ {
-        long j;
-        ulg bytes;
-
-        wpng_info.image_data = (uch *)malloc(rowbytes);
-        if (wpng_info.image_data == NULL) {
-            fprintf(stderr, PROGNAME ":  insufficient memory for row data\n");
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(5);
-        }
-        error = 0;
-        for (j = wpng_info.height;  j > 0L;  --j) {
-            bytes = fread(wpng_info.image_data, 1, rowbytes, wpng_info.infile);
-            if (bytes != rowbytes) {
-                fprintf(stderr, PROGNAME
-                  ":  expected %lu bytes, got %lu bytes (row %ld)\n", rowbytes,
-                  bytes, wpng_info.height-j);
-                ++error;
-                break;
-            }
-            if (writepng_encode_row(&wpng_info) != 0) {
-                fprintf(stderr, PROGNAME
-                  ":  libpng problem (longjmp) while writing row %ld\n",
-                  wpng_info.height-j);
-                ++error;
-                break;
-            }
-        }
-        if (error) {
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(2);
-        }
-        if (writepng_encode_finish(&wpng_info) != 0) {
-            fprintf(stderr, PROGNAME ":  error on final libpng call\n");
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(2);
-        }
-    }
-
-
-    /* OK, we're done (successfully):  clean up all resources and quit */
-
-    fprintf(stderr, "Done.\n");
-    fflush(stderr);
-
-    writepng_cleanup(&wpng_info);
-    wpng_cleanup();
-
-    return 0;
-}
-
-
-
-
-
-static int wpng_isvalid_latin1(uch *p, int len)
-{
-    int i, result = -1;
-
-    for (i = 0;  i < len;  ++i) {
-        if (p[i] == 10 || (p[i] > 31 && p[i] < 127) || p[i] > 160)
-            continue;           /* character is completely OK */
-        if (result < 0 || (p[result] != 27 && p[i] == 27))
-            result = i;         /* mark location of first questionable one */
-    }                           /*  or of first escape character (bad) */
-
-    return result;
-}
-
-
-
-
-
-static void wpng_cleanup(void)
-{
-    if (wpng_info.outfile) {
-        fclose(wpng_info.outfile);
-        wpng_info.outfile = NULL;
-    }
-
-    if (wpng_info.infile) {
-        fclose(wpng_info.infile);
-        wpng_info.infile = NULL;
-    }
-
-    if (wpng_info.image_data) {
-        free(wpng_info.image_data);
-        wpng_info.image_data = NULL;
-    }
-
-    if (wpng_info.row_pointers) {
-        free(wpng_info.row_pointers);
-        wpng_info.row_pointers = NULL;
-    }
-}
-
-
-
-
-#ifdef DOS_OS2_W32
-
-static char *dos_kbd_gets(char *buf, int len)
-{
-    int ch, count=0;
-
-    do {
-        buf[count++] = ch = getche();
-    } while (ch != '\r' && count < len-1);
-
-    buf[count--] = '\0';        /* terminate string */
-    if (buf[count] == '\r')     /* Enter key makes CR, so change to newline */
-        buf[count] = '\n';
-
-    fprintf(stderr, "\n");      /* Enter key does *not* cause a newline */
-    fflush(stderr);
-
-    return buf;
-}
-
-#endif /* DOS_OS2_W32 */
diff --git a/extern/libpng/include/contrib/gregbook/writepng.c b/extern/libpng/include/contrib/gregbook/writepng.c
deleted file mode 100644
index f07f4a8a02..0000000000
--- a/extern/libpng/include/contrib/gregbook/writepng.c
+++ /dev/null
@@ -1,400 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   wpng - simple PNG-writing program                             writepng.c
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-
-#include <stdlib.h>     /* for exit() prototype */
-
-#include "png.h"        /* libpng header; includes zlib.h and setjmp.h */
-#include "writepng.h"   /* typedefs, common macros, public prototypes */
-
-
-/* local prototype */
-
-static void writepng_error_handler(png_structp png_ptr, png_const_charp msg);
-
-
-
-void writepng_version_info(void)
-{
-  fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
-    PNG_LIBPNG_VER_STRING, png_libpng_ver);
-  fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
-    ZLIB_VERSION, zlib_version);
-}
-
-
-
-
-/* returns 0 for success, 2 for libpng problem, 4 for out of memory, 11 for
- *  unexpected pnmtype; note that outfile might be stdout */
-
-int writepng_init(mainprog_info *mainprog_ptr)
-{
-    png_structp  png_ptr;       /* note:  temporary variables! */
-    png_infop  info_ptr;
-    int color_type, interlace_type;
-
-
-    /* could also replace libpng warning-handler (final NULL), but no need: */
-
-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
-      writepng_error_handler, NULL);
-    if (!png_ptr)
-        return 4;   /* out of memory */
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr) {
-        png_destroy_write_struct(&png_ptr, NULL);
-        return 4;   /* out of memory */
-    }
-
-
-    /* setjmp() must be called in every function that calls a PNG-writing
-     * libpng function, unless an alternate error handler was installed--
-     * but compatible error handlers must either use longjmp() themselves
-     * (as in this program) or some other method to return control to
-     * application code, so here we go: */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        return 2;
-    }
-
-
-    /* make sure outfile is (re)opened in BINARY mode */
-
-    png_init_io(png_ptr, mainprog_ptr->outfile);
-
-
-    /* set the compression levels--in general, always want to leave filtering
-     * turned on (except for palette images) and allow all of the filters,
-     * which is the default; want 32K zlib window, unless entire image buffer
-     * is 16K or smaller (unknown here)--also the default; usually want max
-     * compression (NOT the default); and remaining compression flags should
-     * be left alone */
-
-    png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
-/*
-    >> this is default for no filtering; Z_FILTERED is default otherwise:
-    png_set_compression_strategy(png_ptr, Z_DEFAULT_STRATEGY);
-    >> these are all defaults:
-    png_set_compression_mem_level(png_ptr, 8);
-    png_set_compression_window_bits(png_ptr, 15);
-    png_set_compression_method(png_ptr, 8);
- */
-
-
-    /* set the image parameters appropriately */
-
-    if (mainprog_ptr->pnmtype == 5)
-        color_type = PNG_COLOR_TYPE_GRAY;
-    else if (mainprog_ptr->pnmtype == 6)
-        color_type = PNG_COLOR_TYPE_RGB;
-    else if (mainprog_ptr->pnmtype == 8)
-        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-    else {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        return 11;
-    }
-
-    interlace_type = mainprog_ptr->interlaced? PNG_INTERLACE_ADAM7 :
-                                               PNG_INTERLACE_NONE;
-
-    png_set_IHDR(png_ptr, info_ptr, mainprog_ptr->width, mainprog_ptr->height,
-      mainprog_ptr->sample_depth, color_type, interlace_type,
-      PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
-
-    if (mainprog_ptr->gamma > 0.0)
-        png_set_gAMA(png_ptr, info_ptr, mainprog_ptr->gamma);
-
-    if (mainprog_ptr->have_bg) {   /* we know it's RGBA, not gray+alpha */
-        png_color_16  background;
-
-        background.red = mainprog_ptr->bg_red;
-        background.green = mainprog_ptr->bg_green;
-        background.blue = mainprog_ptr->bg_blue;
-        png_set_bKGD(png_ptr, info_ptr, &background);
-    }
-
-    if (mainprog_ptr->have_time) {
-        png_time  modtime;
-
-        png_convert_from_time_t(&modtime, mainprog_ptr->modtime);
-        png_set_tIME(png_ptr, info_ptr, &modtime);
-    }
-
-    if (mainprog_ptr->have_text) {
-        png_text  text[6];
-        int  num_text = 0;
-
-        if (mainprog_ptr->have_text & TEXT_TITLE) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "Title";
-            text[num_text].text = mainprog_ptr->title;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_AUTHOR) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "Author";
-            text[num_text].text = mainprog_ptr->author;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_DESC) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "Description";
-            text[num_text].text = mainprog_ptr->desc;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_COPY) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "Copyright";
-            text[num_text].text = mainprog_ptr->copyright;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_EMAIL) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "E-mail";
-            text[num_text].text = mainprog_ptr->email;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_URL) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "URL";
-            text[num_text].text = mainprog_ptr->url;
-            ++num_text;
-        }
-        png_set_text(png_ptr, info_ptr, text, num_text);
-    }
-
-
-    /* write all chunks up to (but not including) first IDAT */
-
-    png_write_info(png_ptr, info_ptr);
-
-
-    /* if we wanted to write any more text info *after* the image data, we
-     * would set up text struct(s) here and call png_set_text() again, with
-     * just the new data; png_set_tIME() could also go here, but it would
-     * have no effect since we already called it above (only one tIME chunk
-     * allowed) */
-
-
-    /* set up the transformations:  for now, just pack low-bit-depth pixels
-     * into bytes (one, two or four pixels per byte) */
-
-    png_set_packing(png_ptr);
-/*  png_set_shift(png_ptr, &sig_bit);  to scale low-bit-depth values */
-
-
-    /* make sure we save our pointers for use in writepng_encode_image() */
-
-    mainprog_ptr->png_ptr = png_ptr;
-    mainprog_ptr->info_ptr = info_ptr;
-
-
-    /* OK, that's all we need to do for now; return happy */
-
-    return 0;
-}
-
-
-
-
-
-/* returns 0 for success, 2 for libpng (longjmp) problem */
-
-int writepng_encode_image(mainprog_info *mainprog_ptr)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-
-    /* as always, setjmp() must be called in every function that calls a
-     * PNG-writing libpng function */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        mainprog_ptr->png_ptr = NULL;
-        mainprog_ptr->info_ptr = NULL;
-        return 2;
-    }
-
-
-    /* and now we just write the whole image; libpng takes care of interlacing
-     * for us */
-
-    png_write_image(png_ptr, mainprog_ptr->row_pointers);
-
-
-    /* since that's it, we also close out the end of the PNG file now--if we
-     * had any text or time info to write after the IDATs, second argument
-     * would be info_ptr, but we optimize slightly by sending NULL pointer: */
-
-    png_write_end(png_ptr, NULL);
-
-    return 0;
-}
-
-
-
-
-
-/* returns 0 if succeeds, 2 if libpng problem */
-
-int writepng_encode_row(mainprog_info *mainprog_ptr)  /* NON-interlaced only! */
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-
-    /* as always, setjmp() must be called in every function that calls a
-     * PNG-writing libpng function */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        mainprog_ptr->png_ptr = NULL;
-        mainprog_ptr->info_ptr = NULL;
-        return 2;
-    }
-
-
-    /* image_data points at our one row of image data */
-
-    png_write_row(png_ptr, mainprog_ptr->image_data);
-
-    return 0;
-}
-
-
-
-
-
-/* returns 0 if succeeds, 2 if libpng problem */
-
-int writepng_encode_finish(mainprog_info *mainprog_ptr)   /* NON-interlaced! */
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-
-    /* as always, setjmp() must be called in every function that calls a
-     * PNG-writing libpng function */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        mainprog_ptr->png_ptr = NULL;
-        mainprog_ptr->info_ptr = NULL;
-        return 2;
-    }
-
-
-    /* close out PNG file; if we had any text or time info to write after
-     * the IDATs, second argument would be info_ptr: */
-
-    png_write_end(png_ptr, NULL);
-
-    return 0;
-}
-
-
-
-
-
-void writepng_cleanup(mainprog_info *mainprog_ptr)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-    if (png_ptr && info_ptr)
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-}
-
-
-
-
-
-static void writepng_error_handler(png_structp png_ptr, png_const_charp msg)
-{
-    mainprog_info  *mainprog_ptr;
-
-    /* This function, aside from the extra step of retrieving the "error
-     * pointer" (below) and the fact that it exists within the application
-     * rather than within libpng, is essentially identical to libpng's
-     * default error handler.  The second point is critical:  since both
-     * setjmp() and longjmp() are called from the same code, they are
-     * guaranteed to have compatible notions of how big a jmp_buf is,
-     * regardless of whether _BSD_SOURCE or anything else has (or has not)
-     * been defined. */
-
-    fprintf(stderr, "writepng libpng error: %s\n", msg);
-    fflush(stderr);
-
-    mainprog_ptr = png_get_error_ptr(png_ptr);
-    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
-        fprintf(stderr,
-          "writepng severe error:  jmpbuf not recoverable; terminating.\n");
-        fflush(stderr);
-        exit(99);
-    }
-
-    /* Now we have our data structure we can use the information in it
-     * to return control to our own higher level code (all the points
-     * where 'setjmp' is called in this file.)  This will work with other
-     * error handling mechanisms as well - libpng always calls png_error
-     * when it can proceed no further, thus, so long as the error handler
-     * is intercepted, application code can do its own error recovery.
-     */
-    longjmp(mainprog_ptr->jmpbuf, 1);
-}
diff --git a/extern/libpng/include/contrib/gregbook/writepng.h b/extern/libpng/include/contrib/gregbook/writepng.h
deleted file mode 100644
index 78b966b587..0000000000
--- a/extern/libpng/include/contrib/gregbook/writepng.h
+++ /dev/null
@@ -1,133 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   wpng - simple PNG-writing program                             writepng.h
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#ifndef TRUE
-#  define TRUE 1
-#  define FALSE 0
-#endif
-
-#ifndef MAX
-#  define MAX(a,b)  ((a) > (b)? (a) : (b))
-#  define MIN(a,b)  ((a) < (b)? (a) : (b))
-#endif
-
-#ifdef DEBUG
-#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
-#else
-#  define Trace(x)  ;
-#endif
-
-#define TEXT_TITLE    0x01
-#define TEXT_AUTHOR   0x02
-#define TEXT_DESC     0x04
-#define TEXT_COPY     0x08
-#define TEXT_EMAIL    0x10
-#define TEXT_URL      0x20
-
-#define TEXT_TITLE_OFFSET        0
-#define TEXT_AUTHOR_OFFSET      72
-#define TEXT_COPY_OFFSET     (2*72)
-#define TEXT_EMAIL_OFFSET    (3*72)
-#define TEXT_URL_OFFSET      (4*72)
-#define TEXT_DESC_OFFSET     (5*72)
-
-typedef unsigned char   uch;
-typedef unsigned short  ush;
-typedef unsigned long   ulg;
-
-typedef struct _mainprog_info {
-    double gamma;
-    long width;
-    long height;
-    time_t modtime;
-    FILE *infile;
-    FILE *outfile;
-    void *png_ptr;
-    void *info_ptr;
-    uch *image_data;
-    uch **row_pointers;
-    char *title;
-    char *author;
-    char *desc;
-    char *copyright;
-    char *email;
-    char *url;
-    int filter;    /* command-line-filter flag, not PNG row filter! */
-    int pnmtype;
-    int sample_depth;
-    int interlaced;
-    int have_bg;
-    int have_time;
-    int have_text;
-    jmp_buf jmpbuf;
-    uch bg_red;
-    uch bg_green;
-    uch bg_blue;
-} mainprog_info;
-
-
-/* prototypes for public functions in writepng.c */
-
-void writepng_version_info(void);
-
-int writepng_init(mainprog_info *mainprog_ptr);
-
-int writepng_encode_image(mainprog_info *mainprog_ptr);
-
-int writepng_encode_row(mainprog_info *mainprog_ptr);
-
-int writepng_encode_finish(mainprog_info *mainprog_ptr);
-
-void writepng_cleanup(mainprog_info *mainprog_ptr);
diff --git a/extern/libpng/include/contrib/libtests/pngvalid.c b/extern/libpng/include/contrib/libtests/pngvalid.c
deleted file mode 100644
index 3dd6f2133c..0000000000
--- a/extern/libpng/include/contrib/libtests/pngvalid.c
+++ /dev/null
@@ -1,9837 +0,0 @@
-
-/* pngvalid.c - validate libpng by constructing then reading png files.
- *
- * Last changed in libpng 1.5.8 [%RDATE%]
- * Copyright (c) 2012 Glenn Randers-Pehrson
- * Written by John Cunningham Bowler
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * NOTES:
- *   This is a C program that is intended to be linked against libpng.  It
- *   generates bitmaps internally, stores them as PNG files (using the
- *   sequential write code) then reads them back (using the sequential
- *   read code) and validates that the result has the correct data.
- *
- *   The program can be modified and extended to test the correctness of
- *   transformations performed by libpng.
- */
-
-#define _POSIX_SOURCE 1
-#define _ISOC99_SOURCE 1 /* For floating point */
-#define _GNU_SOURCE 1 /* For the floating point exception extension */
-
-#include <signal.h>
-
-#ifdef HAVE_FEENABLEEXCEPT
-#  include <fenv.h>
-#endif
-
-/* Define the following to use this test against your installed libpng, rather
- * than the one being built here:
- */
-#ifdef PNG_FREESTANDING_TESTS
-#  include <png.h>
-#else
-#  include "../../png.h"
-#endif
-
-#if PNG_LIBPNG_VER < 10500
-/* This deliberately lacks the PNG_CONST. */
-typedef png_byte *png_const_bytep;
-
-/* This is copied from 1.5.1 png.h: */
-#define PNG_INTERLACE_ADAM7_PASSES 7
-#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
-#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
-#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
-#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
-#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
-   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
-#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
-   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
-#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
-   (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
-#define PNG_COL_FROM_PASS_COL(xIn, pass) \
-   (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
-#define PNG_PASS_MASK(pass,off) ( \
-   ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
-   ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
-#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
-   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
-#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
-   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
-
-/* These are needed too for the default build: */
-#define PNG_WRITE_16BIT_SUPPORTED
-#define PNG_READ_16BIT_SUPPORTED
-
-/* This comes from pnglibconf.h afer 1.5: */
-#define PNG_FP_1 100000
-#define PNG_GAMMA_THRESHOLD_FIXED\
-   ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
-#endif
-
-#include "zlib.h"   /* For crc32 */
-
-#include <float.h>  /* For floating point constants */
-#include <stdlib.h> /* For malloc */
-#include <string.h> /* For memcpy, memset */
-#include <math.h>   /* For floor */
-
-/* Unused formal parameter errors are removed using the following macro which is
- * expected to have no bad effects on performance.
- */
-#ifndef UNUSED
-#  if defined(__GNUC__) || defined(_MSC_VER)
-#     define UNUSED(param) (void)param;
-#  else
-#     define UNUSED(param)
-#  endif
-#endif
-
-/***************************** EXCEPTION HANDLING *****************************/
-#include "../visupng/cexcept.h"
-
-#ifdef __cplusplus
-#  define this not_the_cpp_this
-#  define new not_the_cpp_new
-#  define voidcast(type, value) static_cast<type>(value)
-#else
-#  define voidcast(type, value) (value)
-#endif /* __cplusplus */
-
-struct png_store;
-define_exception_type(struct png_store*);
-
-/* The following are macros to reduce typing everywhere where the well known
- * name 'the_exception_context' must be defined.
- */
-#define anon_context(ps) struct exception_context *the_exception_context = \
-   &(ps)->exception_context
-#define context(ps,fault) anon_context(ps); png_store *fault
-
-/******************************* UTILITIES ************************************/
-/* Error handling is particularly problematic in production code - error
- * handlers often themselves have bugs which lead to programs that detect
- * minor errors crashing.  The following functions deal with one very
- * common class of errors in error handlers - attempting to format error or
- * warning messages into buffers that are too small.
- */
-static size_t safecat(char *buffer, size_t bufsize, size_t pos,
-   PNG_CONST char *cat)
-{
-   while (pos < bufsize && cat != NULL && *cat != 0)
-      buffer[pos++] = *cat++;
-
-   if (pos >= bufsize)
-      pos = bufsize-1;
-
-   buffer[pos] = 0;
-   return pos;
-}
-
-static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
-{
-   char number[64];
-   sprintf(number, "%d", n);
-   return safecat(buffer, bufsize, pos, number);
-}
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
-    int precision)
-{
-   char number[64];
-   sprintf(number, "%.*f", precision, d);
-   return safecat(buffer, bufsize, pos, number);
-}
-#endif
-
-static PNG_CONST char invalid[] = "invalid";
-static PNG_CONST char sep[] = ": ";
-
-static PNG_CONST char *colour_types[8] =
-{
-   "grayscale", invalid, "truecolour", "indexed-colour",
-   "grayscale with alpha", invalid, "truecolour with alpha", invalid
-};
-
-/* Convert a double precision value to fixed point. */
-static png_fixed_point
-fix(double d)
-{
-   d = floor(d * PNG_FP_1 + .5);
-   return (png_fixed_point)d;
-}
-
-/* Generate random bytes.  This uses a boring repeatable algorithm and it
- * is implemented here so that it gives the same set of numbers on every
- * architecture.  It's a linear congruential generator (Knuth or Sedgewick
- * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
- * Hill, "The Art of Electronics".
- */
-static void
-make_random_bytes(png_uint_32* seed, void* pv, size_t size)
-{
-   png_uint_32 u0 = seed[0], u1 = seed[1];
-   png_bytep bytes = voidcast(png_bytep, pv);
-
-   /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
-    * bit-20.  The top 1 bit is in u1, the bottom 32 are in u0.
-    */
-   size_t i;
-   for (i=0; i<size; ++i)
-   {
-      /* First generate 8 new bits then shift them in at the end. */
-      png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
-      u1 <<= 8;
-      u1 |= u0 >> 24;
-      u0 <<= 8;
-      u0 |= u;
-      *bytes++ = (png_byte)u;
-   }
-
-   seed[0] = u0;
-   seed[1] = u1;
-}
-
-static void
-make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
-{
-   make_random_bytes(seed, bytes, 4);
-}
-
-static void
-randomize(void *pv, size_t size)
-{
-   static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
-   make_random_bytes(random_seed, pv, size);
-}
-
-#define RANDOMIZE(this) randomize(&(this), sizeof (this))
-
-static unsigned int
-random_mod(unsigned int max)
-{
-   unsigned int x;
-
-   RANDOMIZE(x);
-
-   return x % max; /* 0 .. max-1 */
-}
-
-static int
-random_choice(void)
-{
-   unsigned char x;
-
-   RANDOMIZE(x);
-
-   return x & 1;
-}
-
-/* A numeric ID based on PNG file characteristics.  The 'do_interlace' field
- * simply records whether pngvalid did the interlace itself or whether it
- * was done by libpng.  Width and height must be less than 256.  'palette' is an
- * index of the palette to use for formats with a palette (0 otherwise.)
- */
-#define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
-   ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
-    (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
-
-#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
-#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
-#define PALETTE_FROM_ID(id) ((int)(((id) >> 8) & 0x1f))
-#define INTERLACE_FROM_ID(id) ((int)(((id) >> 13) & 0x3))
-#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
-#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
-#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
-
-/* Utility to construct a standard name for a standard image. */
-static size_t
-standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
-    int bit_depth, int npalette, int interlace_type,
-    png_uint_32 w, png_uint_32 h, int do_interlace)
-{
-   pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
-   if (npalette > 0)
-   {
-      pos = safecat(buffer, bufsize, pos, "[");
-      pos = safecatn(buffer, bufsize, pos, npalette);
-      pos = safecat(buffer, bufsize, pos, "]");
-   }
-   pos = safecat(buffer, bufsize, pos, " ");
-   pos = safecatn(buffer, bufsize, pos, bit_depth);
-   pos = safecat(buffer, bufsize, pos, " bit");
-
-   if (interlace_type != PNG_INTERLACE_NONE)
-   {
-      pos = safecat(buffer, bufsize, pos, " interlaced");
-      if (do_interlace)
-         pos = safecat(buffer, bufsize, pos, "(pngvalid)");
-      else
-         pos = safecat(buffer, bufsize, pos, "(libpng)");
-   }
-
-   if (w > 0 || h > 0)
-   {
-      pos = safecat(buffer, bufsize, pos, " ");
-      pos = safecatn(buffer, bufsize, pos, w);
-      pos = safecat(buffer, bufsize, pos, "x");
-      pos = safecatn(buffer, bufsize, pos, h);
-   }
-
-   return pos;
-}
-
-static size_t
-standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
-{
-   return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
-      DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
-      WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
-}
-
-/* Convenience API and defines to list valid formats.  Note that 16 bit read and
- * write support is required to do 16 bit read tests (we must be able to make a
- * 16 bit image to test!)
- */
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-#  define WRITE_BDHI 4
-#  ifdef PNG_READ_16BIT_SUPPORTED
-#     define READ_BDHI 4
-#     define DO_16BIT
-#  endif
-#else
-#  define WRITE_BDHI 3
-#endif
-#ifndef DO_16BIT
-#  define READ_BDHI 3
-#endif
-
-/* The following defines the number of different palettes to generate for
- * each log bit depth of a colour type 3 standard image.
- */
-#define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1 : 16)
-
-static int
-next_format(png_bytep colour_type, png_bytep bit_depth, int* palette_number)
-{
-   if (*bit_depth == 0)
-   {
-      *colour_type = 0, *bit_depth = 1, *palette_number = 0;
-      return 1;
-   }
-
-   if (*colour_type == 3)
-   {
-      /* Add multiple palettes for colour type 3. */
-      if (++*palette_number < PALETTE_COUNT(*bit_depth))
-         return 1;
-
-      *palette_number = 0;
-   }
-
-   *bit_depth = (png_byte)(*bit_depth << 1);
-
-   /* Palette images are restricted to 8 bit depth */
-   if (*bit_depth <= 8
-#     ifdef DO_16BIT
-         || (*colour_type != 3 && *bit_depth <= 16)
-#     endif
-      )
-      return 1;
-
-   /* Move to the next color type, or return 0 at the end. */
-   switch (*colour_type)
-   {
-      case 0:
-         *colour_type = 2;
-         *bit_depth = 8;
-         return 1;
-
-      case 2:
-         *colour_type = 3;
-         *bit_depth = 1;
-         return 1;
-
-      case 3:
-         *colour_type = 4;
-         *bit_depth = 8;
-         return 1;
-
-      case 4:
-         *colour_type = 6;
-         *bit_depth = 8;
-         return 1;
-
-      default:
-         return 0;
-   }
-}
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-static unsigned int
-sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
-    png_uint_32 x, unsigned int sample_index)
-{
-   png_uint_32 bit_index, result;
-
-   /* Find a sample index for the desired sample: */
-   x *= bit_depth;
-   bit_index = x;
-
-   if ((colour_type & 1) == 0) /* !palette */
-   {
-      if (colour_type & 2)
-         bit_index *= 3;
-
-      if (colour_type & 4)
-         bit_index += x; /* Alpha channel */
-
-      /* Multiple channels; select one: */
-      if (colour_type & (2+4))
-         bit_index += sample_index * bit_depth;
-   }
-
-   /* Return the sample from the row as an integer. */
-   row += bit_index >> 3;
-   result = *row;
-
-   if (bit_depth == 8)
-      return result;
-
-   else if (bit_depth > 8)
-      return (result << 8) + *++row;
-
-   /* Less than 8 bits per sample. */
-   bit_index &= 7;
-   return (result >> (8-bit_index-bit_depth)) & ((1U<<bit_depth)-1);
-}
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-/* Copy a single pixel, of a given size, from one buffer to another -
- * while this is basically bit addressed there is an implicit assumption
- * that pixels 8 or more bits in size are byte aligned and that pixels
- * do not otherwise cross byte boundaries.  (This is, so far as I know,
- * universally true in bitmap computer graphics.  [JCB 20101212])
- *
- * NOTE: The to and from buffers may be the same.
- */
-static void
-pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
-   png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize)
-{
-   /* Assume we can multiply by 'size' without overflow because we are
-    * just working in a single buffer.
-    */
-   toIndex *= pixelSize;
-   fromIndex *= pixelSize;
-   if (pixelSize < 8) /* Sub-byte */
-   {
-      /* Mask to select the location of the copied pixel: */
-      unsigned int destMask = ((1U<<pixelSize)-1) << (8-pixelSize-(toIndex&7));
-      /* The following read the entire pixels and clears the extra: */
-      unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
-      unsigned int sourceByte = fromBuffer[fromIndex >> 3];
-
-      /* Don't rely on << or >> supporting '0' here, just in case: */
-      fromIndex &= 7;
-      if (fromIndex > 0) sourceByte <<= fromIndex;
-      if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
-
-      toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
-   }
-   else /* One or more bytes */
-      memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
-}
-
-/* Copy a complete row of pixels, taking into account potential partial
- * bytes at the end.
- */
-static void
-row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth)
-{
-   memcpy(toBuffer, fromBuffer, bitWidth >> 3);
-
-   if ((bitWidth & 7) != 0)
-   {
-      unsigned int mask;
-
-      toBuffer += bitWidth >> 3;
-      fromBuffer += bitWidth >> 3;
-      /* The remaining bits are in the top of the byte, the mask is the bits to
-       * retain.
-       */
-      mask = 0xff >> (bitWidth & 7);
-      *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
-   }
-}
-
-/* Compare pixels - they are assumed to start at the first byte in the
- * given buffers.
- */
-static int
-pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
-{
-#if PNG_LIBPNG_VER < 10506
-   if (memcmp(pa, pb, bit_width>>3) == 0)
-   {
-      png_uint_32 p;
-
-      if ((bit_width & 7) == 0) return 0;
-
-      /* Ok, any differences? */
-      p = pa[bit_width >> 3];
-      p ^= pb[bit_width >> 3];
-
-      if (p == 0) return 0;
-
-      /* There are, but they may not be significant, remove the bits
-       * after the end (the low order bits in PNG.)
-       */
-      bit_width &= 7;
-      p >>= 8-bit_width;
-
-      if (p == 0) return 0;
-   }
-#else
-   /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
-    * bits too:
-    */
-   if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
-      return 0;
-#endif
-
-   /* Return the index of the changed byte. */
-   {
-      png_uint_32 where = 0;
-
-      while (pa[where] == pb[where]) ++where;
-      return 1+where;
-   }
-}
-
-/*************************** BASIC PNG FILE WRITING ***************************/
-/* A png_store takes data from the sequential writer or provides data
- * to the sequential reader.  It can also store the result of a PNG
- * write for later retrieval.
- */
-#define STORE_BUFFER_SIZE 500 /* arbitrary */
-typedef struct png_store_buffer
-{
-   struct png_store_buffer*  prev;    /* NOTE: stored in reverse order */
-   png_byte                  buffer[STORE_BUFFER_SIZE];
-} png_store_buffer;
-
-#define FILE_NAME_SIZE 64
-
-typedef struct store_palette_entry /* record of a single palette entry */
-{
-   png_byte red;
-   png_byte green;
-   png_byte blue;
-   png_byte alpha;
-} store_palette_entry, store_palette[256];
-
-typedef struct png_store_file
-{
-   struct png_store_file*  next;      /* as many as you like... */
-   char                    name[FILE_NAME_SIZE];
-   png_uint_32             id;        /* must be correct (see FILEID) */
-   png_size_t              datacount; /* In this (the last) buffer */
-   png_store_buffer        data;      /* Last buffer in file */
-   int                     npalette;  /* Number of entries in palette */
-   store_palette_entry*    palette;   /* May be NULL */
-} png_store_file;
-
-/* The following is a pool of memory allocated by a single libpng read or write
- * operation.
- */
-typedef struct store_pool
-{
-   struct png_store    *store;   /* Back pointer */
-   struct store_memory *list;    /* List of allocated memory */
-   png_byte             mark[4]; /* Before and after data */
-
-   /* Statistics for this run. */
-   png_alloc_size_t     max;     /* Maximum single allocation */
-   png_alloc_size_t     current; /* Current allocation */
-   png_alloc_size_t     limit;   /* Highest current allocation */
-   png_alloc_size_t     total;   /* Total allocation */
-
-   /* Overall statistics (retained across successive runs). */
-   png_alloc_size_t     max_max;
-   png_alloc_size_t     max_limit;
-   png_alloc_size_t     max_total;
-} store_pool;
-
-typedef struct png_store
-{
-   /* For cexcept.h exception handling - simply store one of these;
-    * the context is a self pointer but it may point to a different
-    * png_store (in fact it never does in this program.)
-    */
-   struct exception_context
-                      exception_context;
-
-   unsigned int       verbose :1;
-   unsigned int       treat_warnings_as_errors :1;
-   unsigned int       expect_error :1;
-   unsigned int       expect_warning :1;
-   unsigned int       saw_warning :1;
-   unsigned int       speed :1;
-   unsigned int       progressive :1; /* use progressive read */
-   unsigned int       validated :1;   /* used as a temporary flag */
-   int                nerrors;
-   int                nwarnings;
-   char               test[128]; /* Name of test */
-   char               error[256];
-
-   /* Read fields */
-   png_structp        pread;    /* Used to read a saved file */
-   png_infop          piread;
-   png_store_file*    current;  /* Set when reading */
-   png_store_buffer*  next;     /* Set when reading */
-   png_size_t         readpos;  /* Position in *next */
-   png_byte*          image;    /* Buffer for reading interlaced images */
-   png_size_t         cb_image; /* Size of this buffer */
-   png_size_t         cb_row;   /* Row size of the image(s) */
-   png_uint_32        image_h;  /* Number of rows in a single image */
-   store_pool         read_memory_pool;
-
-   /* Write fields */
-   png_store_file*    saved;
-   png_structp        pwrite;   /* Used when writing a new file */
-   png_infop          piwrite;
-   png_size_t         writepos; /* Position in .new */
-   char               wname[FILE_NAME_SIZE];
-   png_store_buffer   new;      /* The end of the new PNG file being written. */
-   store_pool         write_memory_pool;
-   store_palette_entry* palette;
-   int                  npalette;
-} png_store;
-
-/* Initialization and cleanup */
-static void
-store_pool_mark(png_bytep mark)
-{
-   static png_uint_32 store_seed[2] = { 0x12345678, 1};
-
-   make_four_random_bytes(store_seed, mark);
-}
-
-/* Use this for random 32 bit values; this function makes sure the result is
- * non-zero.
- */
-static png_uint_32
-random_32(void)
-{
-
-   for(;;)
-   {
-      png_byte mark[4];
-      png_uint_32 result;
-
-      store_pool_mark(mark);
-      result = png_get_uint_32(mark);
-
-      if (result != 0)
-         return result;
-   }
-}
-
-static void
-store_pool_init(png_store *ps, store_pool *pool)
-{
-   memset(pool, 0, sizeof *pool);
-
-   pool->store = ps;
-   pool->list = NULL;
-   pool->max = pool->current = pool->limit = pool->total = 0;
-   pool->max_max = pool->max_limit = pool->max_total = 0;
-   store_pool_mark(pool->mark);
-}
-
-static void
-store_init(png_store* ps)
-{
-   memset(ps, 0, sizeof *ps);
-   init_exception_context(&ps->exception_context);
-   store_pool_init(ps, &ps->read_memory_pool);
-   store_pool_init(ps, &ps->write_memory_pool);
-   ps->verbose = 0;
-   ps->treat_warnings_as_errors = 0;
-   ps->expect_error = 0;
-   ps->expect_warning = 0;
-   ps->saw_warning = 0;
-   ps->speed = 0;
-   ps->progressive = 0;
-   ps->validated = 0;
-   ps->nerrors = ps->nwarnings = 0;
-   ps->pread = NULL;
-   ps->piread = NULL;
-   ps->saved = ps->current = NULL;
-   ps->next = NULL;
-   ps->readpos = 0;
-   ps->image = NULL;
-   ps->cb_image = 0;
-   ps->cb_row = 0;
-   ps->image_h = 0;
-   ps->pwrite = NULL;
-   ps->piwrite = NULL;
-   ps->writepos = 0;
-   ps->new.prev = NULL;
-   ps->palette = NULL;
-   ps->npalette = 0;
-}
-
-static void
-store_freebuffer(png_store_buffer* psb)
-{
-   if (psb->prev)
-   {
-      store_freebuffer(psb->prev);
-      free(psb->prev);
-      psb->prev = NULL;
-   }
-}
-
-static void
-store_freenew(png_store *ps)
-{
-   store_freebuffer(&ps->new);
-   ps->writepos = 0;
-   if (ps->palette != NULL)
-   {
-      free(ps->palette);
-      ps->palette = NULL;
-      ps->npalette = 0;
-   }
-}
-
-static void
-store_storenew(png_store *ps)
-{
-   png_store_buffer *pb;
-
-   if (ps->writepos != STORE_BUFFER_SIZE)
-      png_error(ps->pwrite, "invalid store call");
-
-   pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
-
-   if (pb == NULL)
-      png_error(ps->pwrite, "store new: OOM");
-
-   *pb = ps->new;
-   ps->new.prev = pb;
-   ps->writepos = 0;
-}
-
-static void
-store_freefile(png_store_file **ppf)
-{
-   if (*ppf != NULL)
-   {
-      store_freefile(&(*ppf)->next);
-
-      store_freebuffer(&(*ppf)->data);
-      (*ppf)->datacount = 0;
-      if ((*ppf)->palette != NULL)
-      {
-         free((*ppf)->palette);
-         (*ppf)->palette = NULL;
-         (*ppf)->npalette = 0;
-      }
-      free(*ppf);
-      *ppf = NULL;
-   }
-}
-
-/* Main interface to file storeage, after writing a new PNG file (see the API
- * below) call store_storefile to store the result with the given name and id.
- */
-static void
-store_storefile(png_store *ps, png_uint_32 id)
-{
-   png_store_file *pf = voidcast(png_store_file*, malloc(sizeof *pf));
-   if (pf == NULL)
-      png_error(ps->pwrite, "storefile: OOM");
-   safecat(pf->name, sizeof pf->name, 0, ps->wname);
-   pf->id = id;
-   pf->data = ps->new;
-   pf->datacount = ps->writepos;
-   ps->new.prev = NULL;
-   ps->writepos = 0;
-   pf->palette = ps->palette;
-   pf->npalette = ps->npalette;
-   ps->palette = 0;
-   ps->npalette = 0;
-
-   /* And save it. */
-   pf->next = ps->saved;
-   ps->saved = pf;
-}
-
-/* Generate an error message (in the given buffer) */
-static size_t
-store_message(png_store *ps, png_structp pp, char *buffer, size_t bufsize,
-   size_t pos, PNG_CONST char *msg)
-{
-   if (pp != NULL && pp == ps->pread)
-   {
-      /* Reading a file */
-      pos = safecat(buffer, bufsize, pos, "read: ");
-
-      if (ps->current != NULL)
-      {
-         pos = safecat(buffer, bufsize, pos, ps->current->name);
-         pos = safecat(buffer, bufsize, pos, sep);
-      }
-   }
-
-   else if (pp != NULL && pp == ps->pwrite)
-   {
-      /* Writing a file */
-      pos = safecat(buffer, bufsize, pos, "write: ");
-      pos = safecat(buffer, bufsize, pos, ps->wname);
-      pos = safecat(buffer, bufsize, pos, sep);
-   }
-
-   else
-   {
-      /* Neither reading nor writing (or a memory error in struct delete) */
-      pos = safecat(buffer, bufsize, pos, "pngvalid: ");
-   }
-
-   if (ps->test[0] != 0)
-   {
-      pos = safecat(buffer, bufsize, pos, ps->test);
-      pos = safecat(buffer, bufsize, pos, sep);
-   }
-   pos = safecat(buffer, bufsize, pos, msg);
-   return pos;
-}
-
-/* Verbose output to the error stream: */
-static void
-store_verbose(png_store *ps, png_structp pp, png_const_charp prefix,
-   png_const_charp message)
-{
-   char buffer[512];
-
-   if (prefix)
-      fputs(prefix, stderr);
-
-   (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
-   fputs(buffer, stderr);
-   fputc('\n', stderr);
-}
-
-/* Log an error or warning - the relevant count is always incremented. */
-static void
-store_log(png_store* ps, png_structp pp, png_const_charp message, int is_error)
-{
-   /* The warning is copied to the error buffer if there are no errors and it is
-    * the first warning.  The error is copied to the error buffer if it is the
-    * first error (overwriting any prior warnings).
-    */
-   if (is_error ? (ps->nerrors)++ == 0 :
-       (ps->nwarnings)++ == 0 && ps->nerrors == 0)
-      store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
-
-   if (ps->verbose)
-      store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
-}
-
-/* Internal error function, called with a png_store but no libpng stuff. */
-static void
-internal_error(png_store *ps, png_const_charp message)
-{
-   store_log(ps, NULL, message, 1 /* error */);
-
-   /* And finally throw an exception. */
-   {
-      struct exception_context *the_exception_context = &ps->exception_context;
-      Throw ps;
-   }
-}
-
-/* Functions to use as PNG callbacks. */
-static void
-store_error(png_structp pp, png_const_charp message) /* PNG_NORETURN */
-{
-   png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
-
-   if (!ps->expect_error)
-      store_log(ps, pp, message, 1 /* error */);
-
-   /* And finally throw an exception. */
-   {
-      struct exception_context *the_exception_context = &ps->exception_context;
-      Throw ps;
-   }
-}
-
-static void
-store_warning(png_structp pp, png_const_charp message)
-{
-   png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
-
-   if (!ps->expect_warning)
-      store_log(ps, pp, message, 0 /* warning */);
-   else
-      ps->saw_warning = 1;
-}
-
-/* These somewhat odd functions are used when reading an image to ensure that
- * the buffer is big enough, the png_structp is for errors.
- */
-/* Return a single row from the correct image. */
-static png_bytep
-store_image_row(PNG_CONST png_store* ps, png_structp pp, int nImage,
-   png_uint_32 y)
-{
-   png_size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
-
-   if (ps->image == NULL)
-      png_error(pp, "no allocated image");
-
-   if (coffset + ps->cb_row + 3 > ps->cb_image)
-      png_error(pp, "image too small");
-
-   return ps->image + coffset;
-}
-
-static void
-store_image_free(png_store *ps, png_structp pp)
-{
-   if (ps->image != NULL)
-   {
-      png_bytep image = ps->image;
-
-      if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
-      {
-         if (pp != NULL)
-            png_error(pp, "png_store image overwrite (1)");
-         else
-            store_log(ps, NULL, "png_store image overwrite (2)", 1);
-      }
-
-      ps->image = NULL;
-      ps->cb_image = 0;
-      --image;
-      free(image);
-   }
-}
-
-static void
-store_ensure_image(png_store *ps, png_structp pp, int nImages, png_size_t cbRow,
-   png_uint_32 cRows)
-{
-   png_size_t cb = nImages * cRows * (cbRow + 5);
-
-   if (ps->cb_image < cb)
-   {
-      png_bytep image;
-
-      store_image_free(ps, pp);
-
-      /* The buffer is deliberately mis-aligned. */
-      image = voidcast(png_bytep, malloc(cb+2));
-      if (image == NULL)
-      {
-         /* Called from the startup - ignore the error for the moment. */
-         if (pp == NULL)
-            return;
-
-         png_error(pp, "OOM allocating image buffer");
-      }
-
-      /* These magic tags are used to detect overwrites above. */
-      ++image;
-      image[-1] = 0xed;
-      image[cb] = 0xfe;
-
-      ps->image = image;
-      ps->cb_image = cb;
-   }
-
-   /* We have an adequate sized image; lay out the rows.  There are 2 bytes at
-    * the start and three at the end of each (this ensures that the row
-    * alignment starts out odd - 2+1 and changes for larger images on each row.)
-    */
-   ps->cb_row = cbRow;
-   ps->image_h = cRows;
-
-   /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
-    * This deliberately doesn't match the bits in the size test image which are
-    * outside the image; these are set to 0xff (all 1).  To make the row
-    * comparison work in the 'size' test case the size rows are pre-initialized
-    * to the same value prior to calling 'standard_row'.
-    */
-   memset(ps->image, 178, cb);
-
-   /* Then put in the marks. */
-   while (--nImages >= 0)
-   {
-      png_uint_32 y;
-
-      for (y=0; y<cRows; ++y)
-      {
-         png_bytep row = store_image_row(ps, pp, nImages, y);
-
-         /* The markers: */
-         row[-2] = 190;
-         row[-1] = 239;
-         row[cbRow] = 222;
-         row[cbRow+1] = 173;
-         row[cbRow+2] = 17;
-      }
-   }
-}
-
-static void
-store_image_check(PNG_CONST png_store* ps, png_structp pp, int iImage)
-{
-   png_const_bytep image = ps->image;
-
-   if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
-      png_error(pp, "image overwrite");
-   else
-   {
-      png_size_t cbRow = ps->cb_row;
-      png_uint_32 rows = ps->image_h;
-
-      image += iImage * (cbRow+5) * ps->image_h;
-
-      image += 2; /* skip image first row markers */
-
-      while (rows-- > 0)
-      {
-         if (image[-2] != 190 || image[-1] != 239)
-            png_error(pp, "row start overwritten");
-
-         if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
-            image[cbRow+2] != 17)
-            png_error(pp, "row end overwritten");
-
-         image += cbRow+5;
-      }
-   }
-}
-
-static void
-store_write(png_structp pp, png_bytep pb, png_size_t st)
-{
-   png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
-
-   if (ps->pwrite != pp)
-      png_error(pp, "store state damaged");
-
-   while (st > 0)
-   {
-      size_t cb;
-
-      if (ps->writepos >= STORE_BUFFER_SIZE)
-         store_storenew(ps);
-
-      cb = st;
-
-      if (cb > STORE_BUFFER_SIZE - ps->writepos)
-         cb = STORE_BUFFER_SIZE - ps->writepos;
-
-      memcpy(ps->new.buffer + ps->writepos, pb, cb);
-      pb += cb;
-      st -= cb;
-      ps->writepos += cb;
-   }
-}
-
-static void
-store_flush(png_structp pp)
-{
-   UNUSED(pp) /*DOES NOTHING*/
-}
-
-static size_t
-store_read_buffer_size(png_store *ps)
-{
-   /* Return the bytes available for read in the current buffer. */
-   if (ps->next != &ps->current->data)
-      return STORE_BUFFER_SIZE;
-
-   return ps->current->datacount;
-}
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-/* Return total bytes available for read. */
-static size_t
-store_read_buffer_avail(png_store *ps)
-{
-   if (ps->current != NULL && ps->next != NULL)
-   {
-      png_store_buffer *next = &ps->current->data;
-      size_t cbAvail = ps->current->datacount;
-
-      while (next != ps->next && next != NULL)
-      {
-         next = next->prev;
-         cbAvail += STORE_BUFFER_SIZE;
-      }
-
-      if (next != ps->next)
-         png_error(ps->pread, "buffer read error");
-
-      if (cbAvail > ps->readpos)
-         return cbAvail - ps->readpos;
-   }
-
-   return 0;
-}
-#endif
-
-static int
-store_read_buffer_next(png_store *ps)
-{
-   png_store_buffer *pbOld = ps->next;
-   png_store_buffer *pbNew = &ps->current->data;
-   if (pbOld != pbNew)
-   {
-      while (pbNew != NULL && pbNew->prev != pbOld)
-         pbNew = pbNew->prev;
-
-      if (pbNew != NULL)
-      {
-         ps->next = pbNew;
-         ps->readpos = 0;
-         return 1;
-      }
-
-      png_error(ps->pread, "buffer lost");
-   }
-
-   return 0; /* EOF or error */
-}
-
-/* Need separate implementation and callback to allow use of the same code
- * during progressive read, where the io_ptr is set internally by libpng.
- */
-static void
-store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
-{
-   if (ps->current == NULL || ps->next == NULL)
-      png_error(ps->pread, "store state damaged");
-
-   while (st > 0)
-   {
-      size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
-
-      if (cbAvail > 0)
-      {
-         if (cbAvail > st) cbAvail = st;
-         memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
-         st -= cbAvail;
-         pb += cbAvail;
-         ps->readpos += cbAvail;
-      }
-
-      else if (!store_read_buffer_next(ps))
-         png_error(ps->pread, "read beyond end of file");
-   }
-}
-
-static void
-store_read(png_structp pp, png_bytep pb, png_size_t st)
-{
-   png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
-
-   if (ps == NULL || ps->pread != pp)
-      png_error(pp, "bad store read call");
-
-   store_read_imp(ps, pb, st);
-}
-
-static void
-store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
-{
-   /* Notice that a call to store_read will cause this function to fail because
-    * readpos will be set.
-    */
-   if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
-      png_error(pp, "store state damaged (progressive)");
-
-   do
-   {
-      if (ps->readpos != 0)
-         png_error(pp, "store_read called during progressive read");
-
-      png_process_data(pp, pi, ps->next->buffer, store_read_buffer_size(ps));
-   }
-   while (store_read_buffer_next(ps));
-}
-
-/* The caller must fill this in: */
-static store_palette_entry *
-store_write_palette(png_store *ps, int npalette)
-{
-   if (ps->pwrite == NULL)
-      store_log(ps, NULL, "attempt to write palette without write stream", 1);
-
-   if (ps->palette != NULL)
-      png_error(ps->pwrite, "multiple store_write_palette calls");
-
-   /* This function can only return NULL if called with '0'! */
-   if (npalette > 0)
-   {
-      ps->palette = voidcast(store_palette_entry*, malloc(npalette *
-         sizeof *ps->palette));
-
-      if (ps->palette == NULL)
-         png_error(ps->pwrite, "store new palette: OOM");
-
-      ps->npalette = npalette;
-   }
-
-   return ps->palette;
-}
-
-static store_palette_entry *
-store_current_palette(png_store *ps, int *npalette)
-{
-   /* This is an internal error (the call has been made outside a read
-    * operation.)
-    */
-   if (ps->current == NULL)
-      store_log(ps, ps->pread, "no current stream for palette", 1);
-
-   /* The result may be null if there is no palette. */
-   *npalette = ps->current->npalette;
-   return ps->current->palette;
-}
-
-/***************************** MEMORY MANAGEMENT*** ***************************/
-/* A store_memory is simply the header for an allocated block of memory.  The
- * pointer returned to libpng is just after the end of the header block, the
- * allocated memory is followed by a second copy of the 'mark'.
- */
-typedef struct store_memory
-{
-   store_pool          *pool;    /* Originating pool */
-   struct store_memory *next;    /* Singly linked list */
-   png_alloc_size_t     size;    /* Size of memory allocated */
-   png_byte             mark[4]; /* ID marker */
-} store_memory;
-
-/* Handle a fatal error in memory allocation.  This calls png_error if the
- * libpng struct is non-NULL, else it outputs a message and returns.  This means
- * that a memory problem while libpng is running will abort (png_error) the
- * handling of particular file while one in cleanup (after the destroy of the
- * struct has returned) will simply keep going and free (or attempt to free)
- * all the memory.
- */
-static void
-store_pool_error(png_store *ps, png_structp pp, PNG_CONST char *msg)
-{
-   if (pp != NULL)
-      png_error(pp, msg);
-
-   /* Else we have to do it ourselves.  png_error eventually calls store_log,
-    * above.  store_log accepts a NULL png_structp - it just changes what gets
-    * output by store_message.
-    */
-   store_log(ps, pp, msg, 1 /* error */);
-}
-
-static void
-store_memory_free(png_structp pp, store_pool *pool, store_memory *memory)
-{
-   /* Note that pp may be NULL (see store_pool_delete below), the caller has
-    * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
-    * pointer (for sure), but the contents may have been trashed.
-    */
-   if (memory->pool != pool)
-      store_pool_error(pool->store, pp, "memory corrupted (pool)");
-
-   else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
-      store_pool_error(pool->store, pp, "memory corrupted (start)");
-
-   /* It should be safe to read the size field now. */
-   else
-   {
-      png_alloc_size_t cb = memory->size;
-
-      if (cb > pool->max)
-         store_pool_error(pool->store, pp, "memory corrupted (size)");
-
-      else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
-         != 0)
-         store_pool_error(pool->store, pp, "memory corrupted (end)");
-
-      /* Finally give the library a chance to find problems too: */
-      else
-         {
-         pool->current -= cb;
-         free(memory);
-         }
-   }
-}
-
-static void
-store_pool_delete(png_store *ps, store_pool *pool)
-{
-   if (pool->list != NULL)
-   {
-      fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
-         pool == &ps->read_memory_pool ? "read" : "write",
-         pool == &ps->read_memory_pool ? (ps->current != NULL ?
-            ps->current->name : "unknown file") : ps->wname);
-      ++ps->nerrors;
-
-      do
-      {
-         store_memory *next = pool->list;
-         pool->list = next->next;
-         next->next = NULL;
-
-         fprintf(stderr, "\t%lu bytes @ %p\n",
-             (unsigned long)next->size, (PNG_CONST void*)(next+1));
-         /* The NULL means this will always return, even if the memory is
-          * corrupted.
-          */
-         store_memory_free(NULL, pool, next);
-      }
-      while (pool->list != NULL);
-   }
-
-   /* And reset the other fields too for the next time. */
-   if (pool->max > pool->max_max) pool->max_max = pool->max;
-   pool->max = 0;
-   if (pool->current != 0) /* unexpected internal error */
-      fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
-         ps->test, pool == &ps->read_memory_pool ? "read" : "write",
-         pool == &ps->read_memory_pool ? (ps->current != NULL ?
-            ps->current->name : "unknown file") : ps->wname);
-   pool->current = 0;
-
-   if (pool->limit > pool->max_limit)
-      pool->max_limit = pool->limit;
-
-   pool->limit = 0;
-
-   if (pool->total > pool->max_total)
-      pool->max_total = pool->total;
-
-   pool->total = 0;
-
-   /* Get a new mark too. */
-   store_pool_mark(pool->mark);
-}
-
-/* The memory callbacks: */
-static png_voidp
-store_malloc(png_structp pp, png_alloc_size_t cb)
-{
-   store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
-   store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
-      (sizeof pool->mark)));
-
-   if (new != NULL)
-   {
-      if (cb > pool->max)
-         pool->max = cb;
-
-      pool->current += cb;
-
-      if (pool->current > pool->limit)
-         pool->limit = pool->current;
-
-      pool->total += cb;
-
-      new->size = cb;
-      memcpy(new->mark, pool->mark, sizeof new->mark);
-      memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
-      new->pool = pool;
-      new->next = pool->list;
-      pool->list = new;
-      ++new;
-   }
-
-   else
-   {
-      /* NOTE: the PNG user malloc function cannot use the png_ptr it is passed
-       * other than to retrieve the allocation pointer!  libpng calls the
-       * store_malloc callback in two basic cases:
-       *
-       * 1) From png_malloc; png_malloc will do a png_error itself if NULL is
-       *    returned.
-       * 2) From png_struct or png_info structure creation; png_malloc is
-       *    to return so cleanup can be performed.
-       *
-       * To handle this store_malloc can log a message, but can't do anything
-       * else.
-       */
-      store_log(pool->store, pp, "out of memory", 1 /* is_error */);
-   }
-
-   return new;
-}
-
-static void
-store_free(png_structp pp, png_voidp memory)
-{
-   store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
-   store_memory *this = voidcast(store_memory*, memory), **test;
-
-   /* Because libpng calls store_free with a dummy png_struct when deleting
-    * png_struct or png_info via png_destroy_struct_2 it is necessary to check
-    * the passed in png_structp to ensure it is valid, and not pass it to
-    * png_error if it is not.
-    */
-   if (pp != pool->store->pread && pp != pool->store->pwrite)
-      pp = NULL;
-
-   /* First check that this 'memory' really is valid memory - it must be in the
-    * pool list.  If it is, use the shared memory_free function to free it.
-    */
-   --this;
-   for (test = &pool->list; *test != this; test = &(*test)->next)
-   {
-      if (*test == NULL)
-      {
-         store_pool_error(pool->store, pp, "bad pointer to free");
-         return;
-      }
-   }
-
-   /* Unlink this entry, *test == this. */
-   *test = this->next;
-   this->next = NULL;
-   store_memory_free(pp, pool, this);
-}
-
-/* Setup functions. */
-/* Cleanup when aborting a write or after storing the new file. */
-static void
-store_write_reset(png_store *ps)
-{
-   if (ps->pwrite != NULL)
-   {
-      anon_context(ps);
-
-      Try
-         png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
-
-      Catch_anonymous
-      {
-         /* memory corruption: continue. */
-      }
-
-      ps->pwrite = NULL;
-      ps->piwrite = NULL;
-   }
-
-   /* And make sure that all the memory has been freed - this will output
-    * spurious errors in the case of memory corruption above, but this is safe.
-    */
-   store_pool_delete(ps, &ps->write_memory_pool);
-
-   store_freenew(ps);
-}
-
-/* The following is the main write function, it returns a png_struct and,
- * optionally, a png_info suitable for writiing a new PNG file.  Use
- * store_storefile above to record this file after it has been written.  The
- * returned libpng structures as destroyed by store_write_reset above.
- */
-static png_structp
-set_store_for_write(png_store *ps, png_infopp ppi,
-   PNG_CONST char * volatile name)
-{
-   anon_context(ps);
-
-   Try
-   {
-      if (ps->pwrite != NULL)
-         png_error(ps->pwrite, "write store already in use");
-
-      store_write_reset(ps);
-      safecat(ps->wname, sizeof ps->wname, 0, name);
-
-      /* Don't do the slow memory checks if doing a speed test. */
-      if (ps->speed)
-         ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
-            ps, store_error, store_warning);
-
-      else
-         ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
-            ps, store_error, store_warning, &ps->write_memory_pool,
-            store_malloc, store_free);
-
-      png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
-
-      if (ppi != NULL)
-         *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
-   }
-
-   Catch_anonymous
-      return NULL;
-
-   return ps->pwrite;
-}
-
-/* Cleanup when finished reading (either due to error or in the success case).
- */
-static void
-store_read_reset(png_store *ps)
-{
-   if (ps->pread != NULL)
-   {
-      anon_context(ps);
-
-      Try
-         png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
-
-      Catch_anonymous
-      {
-         /* error already output: continue */
-      }
-
-      ps->pread = NULL;
-      ps->piread = NULL;
-   }
-
-   /* Always do this to be safe. */
-   store_pool_delete(ps, &ps->read_memory_pool);
-
-   ps->current = NULL;
-   ps->next = NULL;
-   ps->readpos = 0;
-   ps->validated = 0;
-}
-
-static void
-store_read_set(png_store *ps, png_uint_32 id)
-{
-   png_store_file *pf = ps->saved;
-
-   while (pf != NULL)
-   {
-      if (pf->id == id)
-      {
-         ps->current = pf;
-         ps->next = NULL;
-         store_read_buffer_next(ps);
-         return;
-      }
-
-      pf = pf->next;
-   }
-
-      {
-      size_t pos;
-      char msg[FILE_NAME_SIZE+64];
-
-      pos = standard_name_from_id(msg, sizeof msg, 0, id);
-      pos = safecat(msg, sizeof msg, pos, ": file not found");
-      png_error(ps->pread, msg);
-      }
-}
-
-/* The main interface for reading a saved file - pass the id number of the file
- * to retrieve.  Ids must be unique or the earlier file will be hidden.  The API
- * returns a png_struct and, optionally, a png_info.  Both of these will be
- * destroyed by store_read_reset above.
- */
-static png_structp
-set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
-   PNG_CONST char *name)
-{
-   /* Set the name for png_error */
-   safecat(ps->test, sizeof ps->test, 0, name);
-
-   if (ps->pread != NULL)
-      png_error(ps->pread, "read store already in use");
-
-   store_read_reset(ps);
-
-   /* Both the create APIs can return NULL if used in their default mode
-    * (because there is no other way of handling an error because the jmp_buf
-    * by default is stored in png_struct and that has not been allocated!)
-    * However, given that store_error works correctly in these circumstances
-    * we don't ever expect NULL in this program.
-    */
-   if (ps->speed)
-      ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps,
-          store_error, store_warning);
-
-   else
-      ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
-          store_error, store_warning, &ps->read_memory_pool, store_malloc,
-          store_free);
-
-   if (ps->pread == NULL)
-   {
-      struct exception_context *the_exception_context = &ps->exception_context;
-
-      store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
-         1 /*error*/);
-
-      Throw ps;
-   }
-
-   store_read_set(ps, id);
-
-   if (ppi != NULL)
-      *ppi = ps->piread = png_create_info_struct(ps->pread);
-
-   return ps->pread;
-}
-
-/* The overall cleanup of a store simply calls the above then removes all the
- * saved files.  This does not delete the store itself.
- */
-static void
-store_delete(png_store *ps)
-{
-   store_write_reset(ps);
-   store_read_reset(ps);
-   store_freefile(&ps->saved);
-   store_image_free(ps, NULL);
-}
-
-/*********************** PNG FILE MODIFICATION ON READ ************************/
-/* Files may be modified on read.  The following structure contains a complete
- * png_store together with extra members to handle modification and a special
- * read callback for libpng.  To use this the 'modifications' field must be set
- * to a list of png_modification structures that actually perform the
- * modification, otherwise a png_modifier is functionally equivalent to a
- * png_store.  There is a special read function, set_modifier_for_read, which
- * replaces set_store_for_read.
- */
-typedef enum modifier_state
-{
-   modifier_start,                        /* Initial value */
-   modifier_signature,                    /* Have a signature */
-   modifier_IHDR                          /* Have an IHDR */
-} modifier_state;
-
-typedef struct CIE_color
-{
-   /* A single CIE tristimulus value, representing the unique response of a
-    * standard observer to a variety of light spectra.  The observer recognizes
-    * all spectra that produce this response as the same color, therefore this
-    * is effectively a description of a color.
-    */
-   double X, Y, Z;
-} CIE_color;
-
-static double
-chromaticity_x(CIE_color c)
-{
-   return c.X / (c.X + c.Y + c.Z);
-}
-
-static double
-chromaticity_y(CIE_color c)
-{
-   return c.Y / (c.X + c.Y + c.Z);
-}
-
-typedef struct color_encoding
-{
-   /* A description of an (R,G,B) encoding of color (as defined above); this
-    * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
-    * (0,0,1) plus an encoding value that is used to encode the linear
-    * components R, G and B to give the actual values R^gamma, G^gamma and
-    * B^gamma that are stored.
-    */
-   double    gamma;            /* Encoding (file) gamma of space */
-   CIE_color red, green, blue; /* End points */
-} color_encoding;
-
-static CIE_color
-white_point(PNG_CONST color_encoding *encoding)
-{
-   CIE_color white;
-   
-   white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
-   white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
-   white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
-
-   return white;
-}
-
-static void
-normalize_color_encoding(color_encoding *encoding)
-{
-   PNG_CONST double whiteY = encoding->red.Y + encoding->green.Y +
-      encoding->blue.Y;
-
-   if (whiteY != 1)
-   {
-      encoding->red.X /= whiteY;
-      encoding->red.Y /= whiteY;
-      encoding->red.Z /= whiteY;
-      encoding->green.X /= whiteY;
-      encoding->green.Y /= whiteY;
-      encoding->green.Z /= whiteY;
-      encoding->blue.X /= whiteY;
-      encoding->blue.Y /= whiteY;
-      encoding->blue.Z /= whiteY;
-   }
-}
-
-static size_t
-safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
-   PNG_CONST color_encoding *e, double encoding_gamma)
-{
-   if (e != 0)
-   {
-      if (encoding_gamma != 0)
-         pos = safecat(buffer, bufsize, pos, "(");
-      pos = safecat(buffer, bufsize, pos, "R(");
-      pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
-      pos = safecat(buffer, bufsize, pos, ",");
-      pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
-      pos = safecat(buffer, bufsize, pos, ",");
-      pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
-      pos = safecat(buffer, bufsize, pos, "),G(");
-      pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
-      pos = safecat(buffer, bufsize, pos, ",");
-      pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
-      pos = safecat(buffer, bufsize, pos, ",");
-      pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
-      pos = safecat(buffer, bufsize, pos, "),B(");
-      pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
-      pos = safecat(buffer, bufsize, pos, ",");
-      pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
-      pos = safecat(buffer, bufsize, pos, ",");
-      pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
-      pos = safecat(buffer, bufsize, pos, ")");
-      if (encoding_gamma != 0)
-         pos = safecat(buffer, bufsize, pos, ")");
-   }
-
-   if (encoding_gamma != 0)
-   {
-      pos = safecat(buffer, bufsize, pos, "^");
-      pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
-   }
-
-   return pos;
-}
-
-typedef struct png_modifier
-{
-   png_store               this;             /* I am a png_store */
-   struct png_modification *modifications;   /* Changes to make */
-
-   modifier_state           state;           /* My state */
-
-   /* Information from IHDR: */
-   png_byte                 bit_depth;       /* From IHDR */
-   png_byte                 colour_type;     /* From IHDR */
-
-   /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
-    * other chunks to be inserted.
-    */
-   png_uint_32              pending_len;
-   png_uint_32              pending_chunk;
-
-   /* Test values */
-   double                   *gammas;
-   unsigned int              ngammas;
-   unsigned int              ngamma_tests;     /* Number of gamma tests to run*/
-   double                    current_gamma;    /* 0 if not set */
-   PNG_CONST color_encoding *encodings;
-   unsigned int              nencodings;
-   PNG_CONST color_encoding *current_encoding; /* If an encoding has been set */
-   unsigned int              encoding_counter; /* For iteration */
-   int                       encoding_ignored; /* Something overwrote it */
-
-   /* Control variables used to iterate through possible encodings, the
-    * following must be set to 0 and tested by the function that uses the
-    * png_modifier because the modifier only sets it to 1 (true.)
-    */
-   unsigned int              repeat :1;   /* Repeat this transform test. */
-   unsigned int              test_uses_encoding :1;
-
-   /* Lowest sbit to test (libpng fails for sbit < 8) */
-   png_byte                 sbitlow;
-
-   /* Error control - these are the limits on errors accepted by the gamma tests
-    * below.
-    */
-   double                   maxout8;  /* Maximum output value error */
-   double                   maxabs8;  /* Absolute sample error 0..1 */
-   double                   maxcalc8; /* Absolute sample error 0..1 */
-   double                   maxpc8;   /* Percentage sample error 0..100% */
-   double                   maxout16; /* Maximum output value error */
-   double                   maxabs16; /* Absolute sample error 0..1 */
-   double                   maxcalc16;/* Absolute sample error 0..1 */
-   double                   maxpc16;  /* Percentage sample error 0..100% */
-
-   /* This is set by transforms that need to allow a higher limit, it is an
-    * internal check on pngvalid to ensure that the calculated error limits are
-    * not ridiculous; without this it is too easy to make a mistake in pngvalid
-    * that allows any value through.
-    */
-   double                   limit;    /* limit on error values, normally 4E-3 */
-
-   /* Log limits - values above this are logged, but not necessarily
-    * warned.
-    */
-   double                   log8;     /* Absolute error in 8 bits to log */
-   double                   log16;    /* Absolute error in 16 bits to log */
-
-   /* Logged 8 and 16 bit errors ('output' values): */
-   double                   error_gray_2;
-   double                   error_gray_4;
-   double                   error_gray_8;
-   double                   error_gray_16;
-   double                   error_color_8;
-   double                   error_color_16;
-   double                   error_indexed;
-
-   /* Flags: */
-   /* Whether to call png_read_update_info, not png_read_start_image, and how
-    * many times to call it.
-    */
-   int                      use_update_info;
-
-   /* Whether or not to interlace. */
-   int                      interlace_type :9; /* int, but must store '1' */
-
-   /* Run the standard tests? */
-   unsigned int             test_standard :1;
-
-   /* Run the odd-sized image and interlace read/write tests? */
-   unsigned int             test_size :1;
-
-   /* Run tests on reading with a combiniation of transforms, */
-   unsigned int             test_transform :1;
-
-   /* When to use the use_input_precision option: */
-   unsigned int             use_input_precision :1;
-   unsigned int             use_input_precision_sbit :1;
-   unsigned int             use_input_precision_16to8 :1;
-
-   /* If set assume that the calculation bit depth is set by the input
-    * precision, not the output precision.
-    */
-   unsigned int             calculations_use_input_precision :1;
-
-   /* If set assume that the calculations are done in 16 bits even if both input
-    * and output are 8 bit or less.
-    */
-   unsigned int             assume_16_bit_calculations :1;
-
-   /* Which gamma tests to run: */
-   unsigned int             test_gamma_threshold :1;
-   unsigned int             test_gamma_transform :1; /* main tests */
-   unsigned int             test_gamma_sbit :1;
-   unsigned int             test_gamma_scale16 :1;
-   unsigned int             test_gamma_background :1;
-   unsigned int             test_gamma_alpha_mode :1;
-   unsigned int             test_gamma_expand16 :1;
-   unsigned int             test_exhaustive :1;
-
-   unsigned int             log :1;   /* Log max error */
-
-   /* Buffer information, the buffer size limits the size of the chunks that can
-    * be modified - they must fit (including header and CRC) into the buffer!
-    */
-   size_t                   flush;           /* Count of bytes to flush */
-   size_t                   buffer_count;    /* Bytes in buffer */
-   size_t                   buffer_position; /* Position in buffer */
-   png_byte                 buffer[1024];
-} png_modifier;
-
-/* This returns true if the test should be stopped now because it has already
- * failed and it is running silently.
- */
-static int fail(png_modifier *pm)
-{
-   return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
-       (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
-}
-
-static void
-modifier_init(png_modifier *pm)
-{
-   memset(pm, 0, sizeof *pm);
-   store_init(&pm->this);
-   pm->modifications = NULL;
-   pm->state = modifier_start;
-   pm->sbitlow = 1U;
-   pm->ngammas = 0;
-   pm->ngamma_tests = 0;
-   pm->gammas = 0;
-   pm->current_gamma = 0;
-   pm->encodings = 0;
-   pm->nencodings = 0;
-   pm->current_encoding = 0;
-   pm->encoding_counter = 0;
-   pm->encoding_ignored = 0;
-   pm->repeat = 0;
-   pm->test_uses_encoding = 0;
-   pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
-   pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
-   pm->limit = 4E-3;
-   pm->log8 = pm->log16 = 0; /* Means 'off' */
-   pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
-   pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
-   pm->error_indexed = 0;
-   pm->use_update_info = 0;
-   pm->interlace_type = PNG_INTERLACE_NONE;
-   pm->test_standard = 0;
-   pm->test_size = 0;
-   pm->test_transform = 0;
-   pm->use_input_precision = 0;
-   pm->use_input_precision_sbit = 0;
-   pm->use_input_precision_16to8 = 0;
-   pm->calculations_use_input_precision = 0;
-   pm->test_gamma_threshold = 0;
-   pm->test_gamma_transform = 0;
-   pm->test_gamma_sbit = 0;
-   pm->test_gamma_scale16 = 0;
-   pm->test_gamma_background = 0;
-   pm->test_gamma_alpha_mode = 0;
-   pm->test_gamma_expand16 = 0;
-   pm->test_exhaustive = 0;
-   pm->log = 0;
-
-   /* Rely on the memset for all the other fields - there are no pointers */
-}
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-/* If pm->calculations_use_input_precision is set then operations will happen
- * with only 8 bit precision unless both the input and output bit depth are 16.
- *
- * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
- * bit precision.  This only affects those of the following limits that pertain
- * to a calculation - not a digitization operation - unless the following API is
- * called directly.
- */
-static double digitize(PNG_CONST png_modifier *pm, double value,
-   int sample_depth, int do_round)
-{
-   /* 'value' is in the range 0 to 1, the result is the same value rounded to a
-    * multiple of the digitization factor - 8 or 16 bits depending on both the
-    * sample depth and the 'assume' setting.  Digitization is normally by
-    * rounding and 'do_round' should be 1, if it is 0 the digitized value will
-    * be truncated.
-    */
-   PNG_CONST unsigned int digitization_factor =
-      (pm->assume_16_bit_calculations || sample_depth == 16) ? 65535 : 255;
-
-   /* Limiting the range is done as a convenience to the caller - it's easier to
-    * do it once here than every time at the call site.
-    */
-   if (value <= 0)
-      value = 0;
-   else if (value >= 1)
-      value = 1;
-
-   value *= digitization_factor;
-   if (do_round) value += .5;
-   return floor(value)/digitization_factor;
-}
-
-static double abserr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
-   /* Absolute error permitted in linear values - affected by the bit depth of
-    * the calculations.
-    */
-   if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
-      !pm->calculations_use_input_precision)))
-      return pm->maxabs16;
-   else
-      return pm->maxabs8;
-}
-
-static double calcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
-   /* Error in the linear composition arithmetic - only relevant when
-    * composition actually happens (0 < alpha < 1).
-    */
-   if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
-      !pm->calculations_use_input_precision)))
-      return pm->maxcalc16;
-   else
-      return pm->maxcalc8;
-}
-
-static double pcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
-   /* Percentage error permitted in the linear values.  Note that the specified
-    * value is a percentage but this routine returns a simple number.
-    */
-   if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
-      !pm->calculations_use_input_precision)))
-      return pm->maxpc16 * .01;
-   else
-      return pm->maxpc8 * .01;
-}
-
-/* Output error - the error in the encoded value.  This is determined by the
- * digitization of the output so can be +/-0.5 in the actual output value.  In
- * the expand_16 case with the current code in libpng the expand happens after
- * all the calculations are done in 8 bit arithmetic, so even though the output
- * depth is 16 the output error is determined by the 8 bit calculation.
- *
- * This limit is not determined by the bit depth of internal calculations.
- *
- * The specified parameter does *not* include the base .5 digitization error but
- * it is added here.
- */
-static double outerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
-   /* There is a serious error in the 2 and 4 bit grayscale transform because
-    * the gamma table value (8 bits) is simply shifted, not rounded, so the
-    * error in 4 bit grayscale gamma is up to the value below.  This is a hack
-    * to allow pngvalid to succeed:
-    *
-    * TODO: fix this in libpng
-    */
-   if (out_depth == 2)
-      return .73182-.5;
-
-   if (out_depth == 4)
-      return .90644-.5;
-
-   if (out_depth == 16 && (in_depth == 16 ||
-      !pm->calculations_use_input_precision))
-      return pm->maxout16;
-
-   /* This is the case where the value was calculated at 8-bit precision then
-    * scaled to 16 bits.
-    */
-   else if (out_depth == 16)
-      return pm->maxout8 * 257;
-
-   else
-      return pm->maxout8;
-}
-
-/* This does the same thing as the above however it returns the value to log,
- * rather than raising a warning.  This is useful for debugging to track down
- * exactly what set of parameters cause high error values.
- */
-static double outlog(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
-   /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
-    * and so must be adjusted for low bit depth grayscale:
-    */
-   if (out_depth <= 8)
-   {
-      if (pm->log8 == 0) /* switched off */
-         return 256;
-
-      if (out_depth < 8)
-         return pm->log8 / 255 * ((1<<out_depth)-1);
-
-      return pm->log8;
-   }
-
-   if (out_depth == 16 && (in_depth == 16 ||
-      !pm->calculations_use_input_precision))
-   {
-      if (pm->log16 == 0)
-         return 65536;
-
-      return pm->log16;
-   }
-
-   /* This is the case where the value was calculated at 8-bit precision then
-    * scaled to 16 bits.
-    */
-   if (pm->log8 == 0)
-      return 65536;
-
-   return pm->log8 * 257;
-}
-
-/* This complements the above by providing the appropriate quantization for the
- * final value.  Normally this would just be quantization to an integral value,
- * but in the 8 bit calculation case it's actually quantization to a multiple of
- * 257!
- */
-static int output_quantization_factor(PNG_CONST png_modifier *pm, int in_depth,
-   int out_depth)
-{
-   if (out_depth == 16 && in_depth != 16
-      && pm->calculations_use_input_precision)
-      return 257;
-   else
-      return 1;
-}
-
-/* One modification structure must be provided for each chunk to be modified (in
- * fact more than one can be provided if multiple separate changes are desired
- * for a single chunk.)  Modifications include adding a new chunk when a
- * suitable chunk does not exist.
- *
- * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
- * or 'added' as appropriate if the modify_fn returns 1 (true).  If the
- * modify_fn is NULL the chunk is simply removed.
- */
-typedef struct png_modification
-{
-   struct png_modification *next;
-   png_uint_32              chunk;
-
-   /* If the following is NULL all matching chunks will be removed: */
-   int                    (*modify_fn)(struct png_modifier *pm,
-                               struct png_modification *me, int add);
-
-   /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
-    * found and modified (and there is a modify_fn) the modify_fn will be called
-    * to add the chunk before the relevant chunk.
-    */
-   png_uint_32              add;
-   unsigned int             modified :1;     /* Chunk was modified */
-   unsigned int             added    :1;     /* Chunk was added */
-   unsigned int             removed  :1;     /* Chunk was removed */
-} png_modification;
-
-static void
-modification_reset(png_modification *pmm)
-{
-   if (pmm != NULL)
-   {
-      pmm->modified = 0;
-      pmm->added = 0;
-      pmm->removed = 0;
-      modification_reset(pmm->next);
-   }
-}
-
-static void
-modification_init(png_modification *pmm)
-{
-   memset(pmm, 0, sizeof *pmm);
-   pmm->next = NULL;
-   pmm->chunk = 0;
-   pmm->modify_fn = NULL;
-   pmm->add = 0;
-   modification_reset(pmm);
-}
-
-static void
-modifier_current_encoding(PNG_CONST png_modifier *pm, color_encoding *ce)
-{
-   if (pm->current_encoding != 0)
-      *ce = *pm->current_encoding;
-
-   else
-      memset(ce, 0, sizeof *ce);
-
-   ce->gamma = pm->current_gamma;
-}
-
-static size_t
-safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
-   PNG_CONST png_modifier *pm)
-{
-   pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
-      pm->current_gamma);
-
-   if (pm->encoding_ignored)
-      pos = safecat(buffer, bufsize, pos, "[overridden]");
-
-   return pos;
-}
-
-/* Iterate through the usefully testable color encodings.  An encoding is one
- * of:
- *
- * 1) Nothing (no color space, no gamma).
- * 2) Just a gamma value from the gamma array (including 1.0)
- * 3) A color space from the encodings array with the corresponding gamma.
- * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
- *
- * The iterator selects these in turn, the randomizer selects one at random,
- * which is used depends on the setting of the 'test_exhaustive' flag.  Notice
- * that this function changes the colour space encoding so it must only be
- * called on completion of the previous test.  This is what 'modifier_reset'
- * does, below.
- *
- * After the function has been called the 'repeat' flag will still be set; the
- * caller of modifier_reset must reset it at the start of each run of the test!
- */
-static unsigned int
-modifier_total_encodings(PNG_CONST png_modifier *pm)
-{
-   return 1 +                 /* (1) nothing */
-      pm->ngammas +           /* (2) gamma values to test */
-      pm->nencodings +        /* (3) total number of encodings */
-      /* The following test only works after the first time through the
-       * png_modifier code because 'bit_depth' is set when the IHDR is read.
-       * modifier_reset, below, preserves the setting until after it has called
-       * the iterate function (also below.)
-       *
-       * For this reason do not rely on this function outside a call to
-       * modifier_reset.
-       */
-      ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
-         pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
-}
-
-static void
-modifier_encoding_iterate(png_modifier *pm)
-{
-   if (!pm->repeat && /* Else something needs the current encoding again. */
-      pm->test_uses_encoding) /* Some transform is encoding dependent */
-   {
-      if (pm->test_exhaustive)
-      {
-         if (++pm->encoding_counter >= modifier_total_encodings(pm))
-            pm->encoding_counter = 0; /* This will stop the repeat */
-      }
-
-      else
-      {
-         /* Not exhaustive - choose an encoding at random; generate a number in
-          * the range 1..(max-1), so the result is always non-zero:
-          */
-         if (pm->encoding_counter == 0)
-            pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
-         else
-            pm->encoding_counter = 0;
-      }
-
-      if (pm->encoding_counter > 0)
-         pm->repeat = 1;
-   }
-
-   else if (!pm->repeat)
-      pm->encoding_counter = 0;
-}
-
-static void
-modifier_reset(png_modifier *pm)
-{
-   store_read_reset(&pm->this);
-   pm->limit = 4E-3;
-   pm->pending_len = pm->pending_chunk = 0;
-   pm->flush = pm->buffer_count = pm->buffer_position = 0;
-   pm->modifications = NULL;
-   pm->state = modifier_start;
-   modifier_encoding_iterate(pm);
-   /* The following must be set in the next run.  In particular
-    * test_uses_encodings must be set in the _ini function of each transform
-    * that looks at the encodings.  (Not the 'add' function!)
-    */
-   pm->test_uses_encoding = 0;
-   pm->current_gamma = 0;
-   pm->current_encoding = 0;
-   pm->encoding_ignored = 0;
-   /* These only become value after IHDR is read: */
-   pm->bit_depth = pm->colour_type = 0;
-}
-
-/* The following must be called before anything else to get the encoding set up
- * on the modifier.  In particular it must be called before the transform init
- * functions are called.
- */
-static void
-modifier_set_encoding(png_modifier *pm)
-{
-   /* Set the encoding to the one specified by the current encoding counter,
-    * first clear out all the settings - this corresponds to an encoding_counter
-    * of 0.
-    */
-   pm->current_gamma = 0;
-   pm->current_encoding = 0;
-   pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
-
-   /* Now, if required, set the gamma and encoding fields. */
-   if (pm->encoding_counter > 0)
-   {
-      /* The gammas[] array is an array of screen gammas, not encoding gammas,
-       * so we need the inverse:
-       */
-      if (pm->encoding_counter <= pm->ngammas)
-         pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
-
-      else
-      {
-         unsigned int i = pm->encoding_counter - pm->ngammas;
-
-         if (i >= pm->nencodings)
-         {
-            i %= pm->nencodings;
-            pm->current_gamma = 1; /* Linear, only in the 16 bit case */
-         }
-
-         else
-            pm->current_gamma = pm->encodings[i].gamma;
-
-         pm->current_encoding = pm->encodings + i;
-      }
-   }
-}
-
-/* Enquiry functions to find out what is set.  Notice that there is an implicit
- * assumption below that the first encoding in the list is the one for sRGB.
- */
-static int
-modifier_color_encoding_is_sRGB(PNG_CONST png_modifier *pm)
-{
-   return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
-      pm->current_encoding->gamma == pm->current_gamma;
-}
-
-static int
-modifier_color_encoding_is_set(PNG_CONST png_modifier *pm)
-{
-   return pm->current_gamma != 0;
-}
-
-/* Convenience macros. */
-#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
-#define CHUNK_IHDR CHUNK(73,72,68,82)
-#define CHUNK_PLTE CHUNK(80,76,84,69)
-#define CHUNK_IDAT CHUNK(73,68,65,84)
-#define CHUNK_IEND CHUNK(73,69,78,68)
-#define CHUNK_cHRM CHUNK(99,72,82,77)
-#define CHUNK_gAMA CHUNK(103,65,77,65)
-#define CHUNK_sBIT CHUNK(115,66,73,84)
-#define CHUNK_sRGB CHUNK(115,82,71,66)
-
-/* The guts of modification are performed during a read. */
-static void
-modifier_crc(png_bytep buffer)
-{
-   /* Recalculate the chunk CRC - a complete chunk must be in
-    * the buffer, at the start.
-    */
-   uInt datalen = png_get_uint_32(buffer);
-   uLong crc = crc32(0, buffer+4, datalen+4);
-   /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
-    */
-   png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
-}
-
-static void
-modifier_setbuffer(png_modifier *pm)
-{
-   modifier_crc(pm->buffer);
-   pm->buffer_count = png_get_uint_32(pm->buffer)+12;
-   pm->buffer_position = 0;
-}
-
-/* Separate the callback into the actual implementation (which is passed the
- * png_modifier explicitly) and the callback, which gets the modifier from the
- * png_struct.
- */
-static void
-modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
-{
-   while (st > 0)
-   {
-      size_t cb;
-      png_uint_32 len, chunk;
-      png_modification *mod;
-
-      if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
-      {
-         static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
-         case modifier_start:
-            store_read_imp(&pm->this, pm->buffer, 8); /* size of signature. */
-            pm->buffer_count = 8;
-            pm->buffer_position = 0;
-
-            if (memcmp(pm->buffer, sign, 8) != 0)
-               png_error(pm->this.pread, "invalid PNG file signature");
-            pm->state = modifier_signature;
-            break;
-
-         case modifier_signature:
-            store_read_imp(&pm->this, pm->buffer, 13+12); /* size of IHDR */
-            pm->buffer_count = 13+12;
-            pm->buffer_position = 0;
-
-            if (png_get_uint_32(pm->buffer) != 13 ||
-                png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
-               png_error(pm->this.pread, "invalid IHDR");
-
-            /* Check the list of modifiers for modifications to the IHDR. */
-            mod = pm->modifications;
-            while (mod != NULL)
-            {
-               if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
-                   (*mod->modify_fn)(pm, mod, 0))
-                  {
-                  mod->modified = 1;
-                  modifier_setbuffer(pm);
-                  }
-
-               /* Ignore removal or add if IHDR! */
-               mod = mod->next;
-            }
-
-            /* Cache information from the IHDR (the modified one.) */
-            pm->bit_depth = pm->buffer[8+8];
-            pm->colour_type = pm->buffer[8+8+1];
-
-            pm->state = modifier_IHDR;
-            pm->flush = 0;
-            break;
-
-         case modifier_IHDR:
-         default:
-            /* Read a new chunk and process it until we see PLTE, IDAT or
-             * IEND.  'flush' indicates that there is still some data to
-             * output from the preceding chunk.
-             */
-            if ((cb = pm->flush) > 0)
-            {
-               if (cb > st) cb = st;
-               pm->flush -= cb;
-               store_read_imp(&pm->this, pb, cb);
-               pb += cb;
-               st -= cb;
-               if (st == 0) return;
-            }
-
-            /* No more bytes to flush, read a header, or handle a pending
-             * chunk.
-             */
-            if (pm->pending_chunk != 0)
-            {
-               png_save_uint_32(pm->buffer, pm->pending_len);
-               png_save_uint_32(pm->buffer+4, pm->pending_chunk);
-               pm->pending_len = 0;
-               pm->pending_chunk = 0;
-            }
-            else
-               store_read_imp(&pm->this, pm->buffer, 8);
-
-            pm->buffer_count = 8;
-            pm->buffer_position = 0;
-
-            /* Check for something to modify or a terminator chunk. */
-            len = png_get_uint_32(pm->buffer);
-            chunk = png_get_uint_32(pm->buffer+4);
-
-            /* Terminators first, they may have to be delayed for added
-             * chunks
-             */
-            if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
-                chunk == CHUNK_IEND)
-            {
-               mod = pm->modifications;
-
-               while (mod != NULL)
-               {
-                  if ((mod->add == chunk ||
-                      (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
-                      mod->modify_fn != NULL && !mod->modified && !mod->added)
-                  {
-                     /* Regardless of what the modify function does do not run
-                      * this again.
-                      */
-                     mod->added = 1;
-
-                     if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
-                     {
-                        /* Reset the CRC on a new chunk */
-                        if (pm->buffer_count > 0)
-                           modifier_setbuffer(pm);
-
-                        else
-                           {
-                           pm->buffer_position = 0;
-                           mod->removed = 1;
-                           }
-
-                        /* The buffer has been filled with something (we assume)
-                         * so output this.  Pend the current chunk.
-                         */
-                        pm->pending_len = len;
-                        pm->pending_chunk = chunk;
-                        break; /* out of while */
-                     }
-                  }
-
-                  mod = mod->next;
-               }
-
-               /* Don't do any further processing if the buffer was modified -
-                * otherwise the code will end up modifying a chunk that was
-                * just added.
-                */
-               if (mod != NULL)
-                  break; /* out of switch */
-            }
-
-            /* If we get to here then this chunk may need to be modified.  To
-             * do this it must be less than 1024 bytes in total size, otherwise
-             * it just gets flushed.
-             */
-            if (len+12 <= sizeof pm->buffer)
-            {
-               store_read_imp(&pm->this, pm->buffer+pm->buffer_count,
-                   len+12-pm->buffer_count);
-               pm->buffer_count = len+12;
-
-               /* Check for a modification, else leave it be. */
-               mod = pm->modifications;
-               while (mod != NULL)
-               {
-                  if (mod->chunk == chunk)
-                  {
-                     if (mod->modify_fn == NULL)
-                     {
-                        /* Remove this chunk */
-                        pm->buffer_count = pm->buffer_position = 0;
-                        mod->removed = 1;
-                        break; /* Terminate the while loop */
-                     }
-
-                     else if ((*mod->modify_fn)(pm, mod, 0))
-                     {
-                        mod->modified = 1;
-                        /* The chunk may have been removed: */
-                        if (pm->buffer_count == 0)
-                        {
-                           pm->buffer_position = 0;
-                           break;
-                        }
-                        modifier_setbuffer(pm);
-                     }
-                  }
-
-                  mod = mod->next;
-               }
-            }
-
-            else
-               pm->flush = len+12 - pm->buffer_count; /* data + crc */
-
-            /* Take the data from the buffer (if there is any). */
-            break;
-      }
-
-      /* Here to read from the modifier buffer (not directly from
-       * the store, as in the flush case above.)
-       */
-      cb = pm->buffer_count - pm->buffer_position;
-
-      if (cb > st)
-         cb = st;
-
-      memcpy(pb, pm->buffer + pm->buffer_position, cb);
-      st -= cb;
-      pb += cb;
-      pm->buffer_position += cb;
-   }
-}
-
-/* The callback: */
-static void
-modifier_read(png_structp pp, png_bytep pb, png_size_t st)
-{
-   png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
-
-   if (pm == NULL || pm->this.pread != pp)
-      png_error(pp, "bad modifier_read call");
-
-   modifier_read_imp(pm, pb, st);
-}
-
-/* Like store_progressive_read but the data is getting changed as we go so we
- * need a local buffer.
- */
-static void
-modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
-{
-   if (pm->this.pread != pp || pm->this.current == NULL ||
-       pm->this.next == NULL)
-      png_error(pp, "store state damaged (progressive)");
-
-   /* This is another Horowitz and Hill random noise generator.  In this case
-    * the aim is to stress the progressive reader with truly horrible variable
-    * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
-    * is generated.  We could probably just count from 1 to 32767 and get as
-    * good a result.
-    */
-   for (;;)
-   {
-      static png_uint_32 noise = 1;
-      png_size_t cb, cbAvail;
-      png_byte buffer[512];
-
-      /* Generate 15 more bits of stuff: */
-      noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
-      cb = noise & 0x1ff;
-
-      /* Check that this number of bytes are available (in the current buffer.)
-       * (This doesn't quite work - the modifier might delete a chunk; unlikely
-       * but possible, it doesn't happen at present because the modifier only
-       * adds chunks to standard images.)
-       */
-      cbAvail = store_read_buffer_avail(&pm->this);
-      if (pm->buffer_count > pm->buffer_position)
-         cbAvail += pm->buffer_count - pm->buffer_position;
-
-      if (cb > cbAvail)
-      {
-         /* Check for EOF: */
-         if (cbAvail == 0)
-            break;
-
-         cb = cbAvail;
-      }
-
-      modifier_read_imp(pm, buffer, cb);
-      png_process_data(pp, pi, buffer, cb);
-   }
-
-   /* Check the invariants at the end (if this fails it's a problem in this
-    * file!)
-    */
-   if (pm->buffer_count > pm->buffer_position ||
-       pm->this.next != &pm->this.current->data ||
-       pm->this.readpos < pm->this.current->datacount)
-      png_error(pp, "progressive read implementation error");
-}
-
-/* Set up a modifier. */
-static png_structp
-set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
-    PNG_CONST char *name)
-{
-   /* Do this first so that the modifier fields are cleared even if an error
-    * happens allocating the png_struct.  No allocation is done here so no
-    * cleanup is required.
-    */
-   pm->state = modifier_start;
-   pm->bit_depth = 0;
-   pm->colour_type = 255;
-
-   pm->pending_len = 0;
-   pm->pending_chunk = 0;
-   pm->flush = 0;
-   pm->buffer_count = 0;
-   pm->buffer_position = 0;
-
-   return set_store_for_read(&pm->this, ppi, id, name);
-}
-
-
-/******************************** MODIFICATIONS *******************************/
-/* Standard modifications to add chunks.  These do not require the _SUPPORTED
- * macros because the chunks can be there regardless of whether this specific
- * libpng supports them.
- */
-typedef struct gama_modification
-{
-   png_modification this;
-   png_fixed_point  gamma;
-} gama_modification;
-
-static int
-gama_modify(png_modifier *pm, png_modification *me, int add)
-{
-   UNUSED(add)
-   /* This simply dumps the given gamma value into the buffer. */
-   png_save_uint_32(pm->buffer, 4);
-   png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
-   png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
-   return 1;
-}
-
-static void
-gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
-{
-   double g;
-
-   modification_init(&me->this);
-   me->this.chunk = CHUNK_gAMA;
-   me->this.modify_fn = gama_modify;
-   me->this.add = CHUNK_PLTE;
-   g = fix(gammad);
-   me->gamma = (png_fixed_point)g;
-   me->this.next = pm->modifications;
-   pm->modifications = &me->this;
-}
-
-typedef struct chrm_modification
-{
-   png_modification          this;
-   PNG_CONST color_encoding *encoding;
-   png_fixed_point           wx, wy, rx, ry, gx, gy, bx, by;
-} chrm_modification;
-
-static int
-chrm_modify(png_modifier *pm, png_modification *me, int add)
-{
-   UNUSED(add)
-   /* As with gAMA this just adds the required cHRM chunk to the buffer. */
-   png_save_uint_32(pm->buffer   , 32);
-   png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
-   png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
-   png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
-   png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
-   png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
-   png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
-   png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
-   png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
-   png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
-   return 1;
-}
-
-static void
-chrm_modification_init(chrm_modification *me, png_modifier *pm,
-   PNG_CONST color_encoding *encoding)
-{
-   CIE_color white = white_point(encoding);
-
-   /* Original end points: */
-   me->encoding = encoding;
-
-   /* Chromaticities (in fixed point): */
-   me->wx = fix(chromaticity_x(white));
-   me->wy = fix(chromaticity_y(white));
-
-   me->rx = fix(chromaticity_x(encoding->red));
-   me->ry = fix(chromaticity_y(encoding->red));
-   me->gx = fix(chromaticity_x(encoding->green));
-   me->gy = fix(chromaticity_y(encoding->green));
-   me->bx = fix(chromaticity_x(encoding->blue));
-   me->by = fix(chromaticity_y(encoding->blue));
-
-   modification_init(&me->this);
-   me->this.chunk = CHUNK_cHRM;
-   me->this.modify_fn = chrm_modify;
-   me->this.add = CHUNK_PLTE;
-   me->this.next = pm->modifications;
-   pm->modifications = &me->this;
-}
-
-typedef struct srgb_modification
-{
-   png_modification this;
-   png_byte         intent;
-} srgb_modification;
-
-static int
-srgb_modify(png_modifier *pm, png_modification *me, int add)
-{
-   UNUSED(add)
-   /* As above, ignore add and just make a new chunk */
-   png_save_uint_32(pm->buffer, 1);
-   png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
-   pm->buffer[8] = ((srgb_modification*)me)->intent;
-   return 1;
-}
-
-static void
-srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
-{
-   modification_init(&me->this);
-   me->this.chunk = CHUNK_sBIT;
-
-   if (intent <= 3) /* if valid, else *delete* sRGB chunks */
-   {
-      me->this.modify_fn = srgb_modify;
-      me->this.add = CHUNK_PLTE;
-      me->intent = intent;
-   }
-
-   else
-   {
-      me->this.modify_fn = 0;
-      me->this.add = 0;
-      me->intent = 0;
-   }
-
-   me->this.next = pm->modifications;
-   pm->modifications = &me->this;
-}
-
-typedef struct sbit_modification
-{
-   png_modification this;
-   png_byte         sbit;
-} sbit_modification;
-
-static int
-sbit_modify(png_modifier *pm, png_modification *me, int add)
-{
-   png_byte sbit = ((sbit_modification*)me)->sbit;
-   if (pm->bit_depth > sbit)
-   {
-      int cb = 0;
-      switch (pm->colour_type)
-      {
-         case 0:
-            cb = 1;
-            break;
-
-         case 2:
-         case 3:
-            cb = 3;
-            break;
-
-         case 4:
-            cb = 2;
-            break;
-
-         case 6:
-            cb = 4;
-            break;
-
-         default:
-            png_error(pm->this.pread,
-               "unexpected colour type in sBIT modification");
-      }
-
-      png_save_uint_32(pm->buffer, cb);
-      png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
-
-      while (cb > 0)
-         (pm->buffer+8)[--cb] = sbit;
-
-      return 1;
-   }
-   else if (!add)
-   {
-      /* Remove the sBIT chunk */
-      pm->buffer_count = pm->buffer_position = 0;
-      return 1;
-   }
-   else
-      return 0; /* do nothing */
-}
-
-static void
-sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
-{
-   modification_init(&me->this);
-   me->this.chunk = CHUNK_sBIT;
-   me->this.modify_fn = sbit_modify;
-   me->this.add = CHUNK_PLTE;
-   me->sbit = sbit;
-   me->this.next = pm->modifications;
-   pm->modifications = &me->this;
-}
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-/***************************** STANDARD PNG FILES *****************************/
-/* Standard files - write and save standard files. */
-/* There are two basic forms of standard images.  Those which attempt to have
- * all the possible pixel values (not possible for 16bpp images, but a range of
- * values are produced) and those which have a range of image sizes.  The former
- * are used for testing transforms, in particular gamma correction and bit
- * reduction and increase.  The latter are reserved for testing the behavior of
- * libpng with respect to 'odd' image sizes - particularly small images where
- * rows become 1 byte and interlace passes disappear.
- *
- * The first, most useful, set are the 'transform' images, the second set of
- * small images are the 'size' images.
- *
- * The transform files are constructed with rows which fit into a 1024 byte row
- * buffer.  This makes allocation easier below.  Further regardless of the file
- * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
- *
- * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
- * and with an ID derived from the colour type, bit depth and interlace type
- * as above (FILEID).  The width (128) and height (variable) are not stored in
- * the FILEID - instead the fields are set to 0, indicating a transform file.
- *
- * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
- * a maximum width of 16 pixels (for the 64bpp case.)  They also have a maximum
- * height of 16 rows.  The width and height are stored in the FILEID and, being
- * non-zero, indicate a size file.
- *
- * For palette image (colour type 3) multiple transform images are stored with
- * the same bit depth to allow testing of more colour combinations -
- * particularly important for testing the gamma code because libpng uses a
- * different code path for palette images.  For size images a single palette is
- * used.
- */
-
-/* Make a 'standard' palette.  Because there are only 256 entries in a palette
- * (maximum) this actually makes a random palette in the hope that enough tests
- * will catch enough errors.  (Note that the same palette isn't produced every
- * time for the same test - it depends on what previous tests have been run -
- * but a given set of arguments to pngvalid will always produce the same palette
- * at the same test!  This is why pseudo-random number generators are useful for
- * testing.)
- *
- * The store must be open for write when this is called, otherwise an internal
- * error will occur.  This routine contains its own magic number seed, so the
- * palettes generated don't change if there are intervening errors (changing the
- * calls to the store_mark seed.)
- */
-static store_palette_entry *
-make_standard_palette(png_store* ps, int npalette, int do_tRNS)
-{
-   static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
-
-   int i = 0;
-   png_byte values[256][4];
-
-   /* Always put in black and white plus the six primary and secondary colors.
-    */
-   for (; i<8; ++i)
-   {
-      values[i][1] = (i&1) ? 255 : 0;
-      values[i][2] = (i&2) ? 255 : 0;
-      values[i][3] = (i&4) ? 255 : 0;
-   }
-
-   /* Then add 62 grays (one quarter of the remaining 256 slots). */
-   {
-      int j = 0;
-      png_byte random_bytes[4];
-      png_byte need[256];
-
-      need[0] = 0; /*got black*/
-      memset(need+1, 1, (sizeof need)-2); /*need these*/
-      need[255] = 0; /*but not white*/
-
-      while (i<70)
-      {
-         png_byte b;
-
-         if (j==0)
-         {
-            make_four_random_bytes(palette_seed, random_bytes);
-            j = 4;
-         }
-
-         b = random_bytes[--j];
-         if (need[b])
-         {
-            values[i][1] = b;
-            values[i][2] = b;
-            values[i++][3] = b;
-         }
-      }
-   }
-
-   /* Finally add 192 colors at random - don't worry about matches to things we
-    * already have, chance is less than 1/65536.  Don't worry about grays,
-    * chance is the same, so we get a duplicate or extra gray less than 1 time
-    * in 170.
-    */
-   for (; i<256; ++i)
-      make_four_random_bytes(palette_seed, values[i]);
-
-   /* Fill in the alpha values in the first byte.  Just use all possible values
-    * (0..255) in an apparently random order:
-    */
-   {
-      store_palette_entry *palette;
-      png_byte selector[4];
-
-      make_four_random_bytes(palette_seed, selector);
-
-      if (do_tRNS)
-         for (i=0; i<256; ++i)
-            values[i][0] = (png_byte)(i ^ selector[0]);
-
-      else
-         for (i=0; i<256; ++i)
-            values[i][0] = 255; /* no transparency/tRNS chunk */
-
-      /* 'values' contains 256 ARGB values, but we only need 'npalette'.
-       * 'npalette' will always be a power of 2: 2, 4, 16 or 256.  In the low
-       * bit depth cases select colors at random, else it is difficult to have
-       * a set of low bit depth palette test with any chance of a reasonable
-       * range of colors.  Do this by randomly permuting values into the low
-       * 'npalette' entries using an XOR mask generated here.  This also
-       * permutes the npalette == 256 case in a potentially useful way (there is
-       * no relationship between palette index and the color value therein!)
-       */
-      palette = store_write_palette(ps, npalette);
-
-      for (i=0; i<npalette; ++i)
-      {
-         palette[i].alpha = values[i ^ selector[1]][0];
-         palette[i].red   = values[i ^ selector[1]][1];
-         palette[i].green = values[i ^ selector[1]][2];
-         palette[i].blue  = values[i ^ selector[1]][3];
-      }
-
-      return palette;
-   }
-}
-
-/* Initialize a standard palette on a write stream.  The 'do_tRNS' argument
- * indicates whether or not to also set the tRNS chunk.
- */
-static void
-init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
-   int do_tRNS)
-{
-   store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
-
-   {
-      int i;
-      png_color palette[256];
-
-      /* Set all entries to detect overread errors. */
-      for (i=0; i<npalette; ++i)
-      {
-         palette[i].red = ppal[i].red;
-         palette[i].green = ppal[i].green;
-         palette[i].blue = ppal[i].blue;
-      }
-
-      /* Just in case fill in the rest with detectable values: */
-      for (; i<256; ++i)
-         palette[i].red = palette[i].green = palette[i].blue = 42;
-
-      png_set_PLTE(pp, pi, palette, npalette);
-   }
-
-   if (do_tRNS)
-   {
-      int i, j;
-      png_byte tRNS[256];
-
-      /* Set all the entries, but skip trailing opaque entries */
-      for (i=j=0; i<npalette; ++i)
-         if ((tRNS[i] = ppal[i].alpha) < 255)
-            j = i+1;
-
-      /* Fill in the remainder with a detectable value: */
-      for (; i<256; ++i)
-         tRNS[i] = 24;
-
-      if (j > 0)
-         png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
-   }
-}
-
-/* The number of passes is related to the interlace type. There was no libpng
- * API to determine this prior to 1.5, so we need an inquiry function:
- */
-static int
-npasses_from_interlace_type(png_structp pp, int interlace_type)
-{
-   switch (interlace_type)
-   {
-   default:
-      png_error(pp, "invalid interlace type");
-
-   case PNG_INTERLACE_NONE:
-      return 1;
-
-   case PNG_INTERLACE_ADAM7:
-      return PNG_INTERLACE_ADAM7_PASSES;
-   }
-}
-
-static unsigned int
-bit_size(png_structp pp, png_byte colour_type, png_byte bit_depth)
-{
-   switch (colour_type)
-   {
-      default: png_error(pp, "invalid color type");
-
-      case 0:  return bit_depth;
-
-      case 2:  return 3*bit_depth;
-
-      case 3:  return bit_depth;
-
-      case 4:  return 2*bit_depth;
-
-      case 6:  return 4*bit_depth;
-   }
-}
-
-#define TRANSFORM_WIDTH  128U
-#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
-#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
-#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
-#define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
-
-static size_t
-transform_rowsize(png_structp pp, png_byte colour_type, png_byte bit_depth)
-{
-   return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
-}
-
-/* transform_width(pp, colour_type, bit_depth) current returns the same number
- * every time, so just use a macro:
- */
-#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
-
-static png_uint_32
-transform_height(png_structp pp, png_byte colour_type, png_byte bit_depth)
-{
-   switch (bit_size(pp, colour_type, bit_depth))
-   {
-      case 1:
-      case 2:
-      case 4:
-         return 1;   /* Total of 128 pixels */
-
-      case 8:
-         return 2;   /* Total of 256 pixels/bytes */
-
-      case 16:
-         return 512; /* Total of 65536 pixels */
-
-      case 24:
-      case 32:
-         return 512; /* 65536 pixels */
-
-      case 48:
-      case 64:
-         return 2048;/* 4 x 65536 pixels. */
-#        define TRANSFORM_HEIGHTMAX 2048
-
-      default:
-         return 0;   /* Error, will be caught later */
-   }
-}
-
-/* The following can only be defined here, now we have the definitions
- * of the transform image sizes.
- */
-static png_uint_32
-standard_width(png_structp pp, png_uint_32 id)
-{
-   png_uint_32 width = WIDTH_FROM_ID(id);
-   UNUSED(pp)
-
-   if (width == 0)
-      width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
-
-   return width;
-}
-
-static png_uint_32
-standard_height(png_structp pp, png_uint_32 id)
-{
-   png_uint_32 height = HEIGHT_FROM_ID(id);
-
-   if (height == 0)
-      height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
-
-   return height;
-}
-
-static png_uint_32
-standard_rowsize(png_structp pp, png_uint_32 id)
-{
-   png_uint_32 width = standard_width(pp, id);
-
-   /* This won't overflow: */
-   width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
-   return (width + 7) / 8;
-}
-
-static void
-transform_row(png_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
-   png_byte colour_type, png_byte bit_depth, png_uint_32 y)
-{
-   png_uint_32 v = y << 7;
-   png_uint_32 i = 0;
-
-   switch (bit_size(pp, colour_type, bit_depth))
-   {
-      case 1:
-         while (i<128/8) buffer[i] = v & 0xff, v += 17, ++i;
-         return;
-
-      case 2:
-         while (i<128/4) buffer[i] = v & 0xff, v += 33, ++i;
-         return;
-
-      case 4:
-         while (i<128/2) buffer[i] = v & 0xff, v += 65, ++i;
-         return;
-
-      case 8:
-         /* 256 bytes total, 128 bytes in each row set as follows: */
-         while (i<128) buffer[i] = v & 0xff, ++v, ++i;
-         return;
-
-      case 16:
-         /* Generate all 65536 pixel values in order, which includes the 8 bit
-          * GA case as well as the 16 bit G case.
-          */
-         while (i<128)
-            buffer[2*i] = (v>>8) & 0xff, buffer[2*i+1] = v & 0xff, ++v, ++i;
-
-         return;
-
-      case 24:
-         /* 65535 pixels, but rotate the values. */
-         while (i<128)
-         {
-            /* Three bytes per pixel, r, g, b, make b by r^g */
-            buffer[3*i+0] = (v >> 8) & 0xff;
-            buffer[3*i+1] = v & 0xff;
-            buffer[3*i+2] = ((v >> 8) ^ v) & 0xff;
-            ++v;
-            ++i;
-         }
-
-         return;
-
-      case 32:
-         /* 65535 pixels, r, g, b, a; just replicate */
-         while (i<128)
-         {
-            buffer[4*i+0] = (v >> 8) & 0xff;
-            buffer[4*i+1] = v & 0xff;
-            buffer[4*i+2] = (v >> 8) & 0xff;
-            buffer[4*i+3] = v & 0xff;
-            ++v;
-            ++i;
-         }
-
-         return;
-
-      case 48:
-         /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
-          * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
-          */
-         while (i<128)
-         {
-            png_uint_32 t = v++;
-            buffer[6*i+0] = (t >> 8) & 0xff;
-            buffer[6*i+1] = t & 0xff;
-            t *= 257;
-            buffer[6*i+2] = (t >> 8) & 0xff;
-            buffer[6*i+3] = t & 0xff;
-            t *= 17;
-            buffer[6*i+4] = (t >> 8) & 0xff;
-            buffer[6*i+5] = t & 0xff;
-            ++i;
-         }
-
-         return;
-
-      case 64:
-         /* As above in the 32 bit case. */
-         while (i<128)
-         {
-            png_uint_32 t = v++;
-            buffer[8*i+0] = (t >> 8) & 0xff;
-            buffer[8*i+1] = t & 0xff;
-            buffer[8*i+4] = (t >> 8) & 0xff;
-            buffer[8*i+5] = t & 0xff;
-            t *= 257;
-            buffer[8*i+2] = (t >> 8) & 0xff;
-            buffer[8*i+3] = t & 0xff;
-            buffer[8*i+6] = (t >> 8) & 0xff;
-            buffer[8*i+7] = t & 0xff;
-            ++i;
-         }
-         return;
-
-      default:
-         break;
-   }
-
-   png_error(pp, "internal error");
-}
-
-/* This is just to do the right cast - could be changed to a function to check
- * 'bd' but there isn't much point.
- */
-#define DEPTH(bd) ((png_byte)(1U << (bd)))
-
-/* Make a standardized image given a an image colour type, bit depth and
- * interlace type.  The standard images have a very restricted range of
- * rows and heights and are used for testing transforms rather than image
- * layout details.  See make_size_images below for a way to make images
- * that test odd sizes along with the libpng interlace handling.
- */
-static void
-make_transform_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
-    png_byte PNG_CONST bit_depth, int palette_number, int interlace_type,
-    png_const_charp name)
-{
-   context(ps, fault);
-
-   Try
-   {
-      png_infop pi;
-      png_structp pp = set_store_for_write(ps, &pi, name);
-      png_uint_32 h;
-
-      /* In the event of a problem return control to the Catch statement below
-       * to do the clean up - it is not possible to 'return' directly from a Try
-       * block.
-       */
-      if (pp == NULL)
-         Throw ps;
-
-      h = transform_height(pp, colour_type, bit_depth);
-
-      png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth), h,
-         bit_depth, colour_type, interlace_type,
-         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
-#ifdef PNG_TEXT_SUPPORTED
-      {
-         static char key[] = "image name"; /* must be writeable */
-         size_t pos;
-         png_text text;
-         char copy[FILE_NAME_SIZE];
-
-         /* Use a compressed text string to test the correct interaction of text
-          * compression and IDAT compression.
-          */
-         text.compression = PNG_TEXT_COMPRESSION_zTXt;
-         text.key = key;
-         /* Yuck: the text must be writable! */
-         pos = safecat(copy, sizeof copy, 0, ps->wname);
-         text.text = copy;
-         text.text_length = pos;
-         text.itxt_length = 0;
-         text.lang = 0;
-         text.lang_key = 0;
-
-         png_set_text(pp, pi, &text, 1);
-      }
-#endif
-
-      if (colour_type == 3) /* palette */
-         init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
-
-      png_write_info(pp, pi);
-
-      if (png_get_rowbytes(pp, pi) !=
-          transform_rowsize(pp, colour_type, bit_depth))
-         png_error(pp, "row size incorrect");
-
-      else
-      {
-         /* Somewhat confusingly this must be called *after* png_write_info
-          * because if it is called before, the information in *pp has not been
-          * updated to reflect the interlaced image.
-          */
-         int npasses = png_set_interlace_handling(pp);
-         int pass;
-
-         if (npasses != npasses_from_interlace_type(pp, interlace_type))
-            png_error(pp, "write: png_set_interlace_handling failed");
-
-         for (pass=0; pass<npasses; ++pass)
-         {
-            png_uint_32 y;
-
-            for (y=0; y<h; ++y)
-            {
-               png_byte buffer[TRANSFORM_ROWMAX];
-
-               transform_row(pp, buffer, colour_type, bit_depth, y);
-               png_write_row(pp, buffer);
-            }
-         }
-      }
-
-#ifdef PNG_TEXT_SUPPORTED
-      {
-         static char key[] = "end marker";
-         static char comment[] = "end";
-         png_text text;
-
-         /* Use a compressed text string to test the correct interaction of text
-          * compression and IDAT compression.
-          */
-         text.compression = PNG_TEXT_COMPRESSION_zTXt;
-         text.key = key;
-         text.text = comment;
-         text.text_length = (sizeof comment)-1;
-         text.itxt_length = 0;
-         text.lang = 0;
-         text.lang_key = 0;
-
-         png_set_text(pp, pi, &text, 1);
-      }
-#endif
-
-      png_write_end(pp, pi);
-
-      /* And store this under the appropriate id, then clean up. */
-      store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
-         interlace_type, 0, 0, 0));
-
-      store_write_reset(ps);
-   }
-
-   Catch(fault)
-   {
-      /* Use the png_store returned by the exception. This may help the compiler
-       * because 'ps' is not used in this branch of the setjmp.  Note that fault
-       * and ps will always be the same value.
-       */
-      store_write_reset(fault);
-   }
-}
-
-static void
-make_transform_images(png_store *ps)
-{
-   png_byte colour_type = 0;
-   png_byte bit_depth = 0;
-   int palette_number = 0;
-
-   /* This is in case of errors. */
-   safecat(ps->test, sizeof ps->test, 0, "make standard images");
-
-   /* Use next_format to enumerate all the combinations we test, including
-    * generating multiple low bit depth palette images.
-    */
-   while (next_format(&colour_type, &bit_depth, &palette_number))
-   {
-      int interlace_type;
-
-      for (interlace_type = PNG_INTERLACE_NONE;
-           interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
-      {
-         char name[FILE_NAME_SIZE];
-
-         standard_name(name, sizeof name, 0, colour_type, bit_depth,
-            palette_number, interlace_type, 0, 0, 0);
-         make_transform_image(ps, colour_type, bit_depth, palette_number,
-            interlace_type, name);
-      }
-   }
-}
-
-/* The following two routines use the PNG interlace support macros from
- * png.h to interlace or deinterlace rows.
- */
-static void
-interlace_row(png_bytep buffer, png_const_bytep imageRow,
-   unsigned int pixel_size, png_uint_32 w, int pass)
-{
-   png_uint_32 xin, xout, xstep;
-
-   /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
-    * code is presented this way to make it easier to understand.  In practice
-    * consult the code in the libpng source to see other ways of doing this.
-    */
-   xin = PNG_PASS_START_COL(pass);
-   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
-
-   for (xout=0; xin<w; xin+=xstep)
-   {
-      pixel_copy(buffer, xout, imageRow, xin, pixel_size);
-      ++xout;
-   }
-}
-
-static void
-deinterlace_row(png_bytep buffer, png_const_bytep row,
-   unsigned int pixel_size, png_uint_32 w, int pass)
-{
-   /* The inverse of the above, 'row' is part of row 'y' of the output image,
-    * in 'buffer'.  The image is 'w' wide and this is pass 'pass', distribute
-    * the pixels of row into buffer and return the number written (to allow
-    * this to be checked).
-    */
-   png_uint_32 xin, xout, xstep;
-
-   xout = PNG_PASS_START_COL(pass);
-   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
-
-   for (xin=0; xout<w; xout+=xstep)
-   {
-      pixel_copy(buffer, xout, row, xin, pixel_size);
-      ++xin;
-   }
-}
-
-/* Build a single row for the 'size' test images; this fills in only the
- * first bit_width bits of the sample row.
- */
-static void
-size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
-{
-   /* height is in the range 1 to 16, so: */
-   y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
-   /* the following ensures bits are set in small images: */
-   y ^= 0xA5;
-
-   while (bit_width >= 8)
-      *buffer++ = (png_byte)y++, bit_width -= 8;
-
-   /* There may be up to 7 remaining bits, these go in the most significant
-    * bits of the byte.
-    */
-   if (bit_width > 0)
-   {
-      png_uint_32 mask = (1U<<(8-bit_width))-1;
-      *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
-   }
-}
-
-static void
-make_size_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
-    png_byte PNG_CONST bit_depth, int PNG_CONST interlace_type,
-    png_uint_32 PNG_CONST w, png_uint_32 PNG_CONST h,
-    int PNG_CONST do_interlace)
-{
-   context(ps, fault);
-
-   Try
-   {
-      png_infop pi;
-      png_structp pp;
-      unsigned int pixel_size;
-
-      /* Make a name and get an appropriate id for the store: */
-      char name[FILE_NAME_SIZE];
-      PNG_CONST png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
-         interlace_type, w, h, do_interlace);
-
-      standard_name_from_id(name, sizeof name, 0, id);
-      pp = set_store_for_write(ps, &pi, name);
-
-      /* In the event of a problem return control to the Catch statement below
-       * to do the clean up - it is not possible to 'return' directly from a Try
-       * block.
-       */
-      if (pp == NULL)
-         Throw ps;
-
-      png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
-         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
-      if (colour_type == 3) /* palette */
-         init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
-
-      png_write_info(pp, pi);
-
-      /* Calculate the bit size, divide by 8 to get the byte size - this won't
-       * overflow because we know the w values are all small enough even for
-       * a system where 'unsigned int' is only 16 bits.
-       */
-      pixel_size = bit_size(pp, colour_type, bit_depth);
-      if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
-         png_error(pp, "row size incorrect");
-
-      else
-      {
-         int npasses = npasses_from_interlace_type(pp, interlace_type);
-         png_uint_32 y;
-         int pass;
-         png_byte image[16][SIZE_ROWMAX];
-
-         /* To help consistent error detection make the parts of this buffer
-          * that aren't set below all '1':
-          */
-         memset(image, 0xff, sizeof image);
-
-         if (!do_interlace && npasses != png_set_interlace_handling(pp))
-            png_error(pp, "write: png_set_interlace_handling failed");
-
-         /* Prepare the whole image first to avoid making it 7 times: */
-         for (y=0; y<h; ++y)
-            size_row(image[y], w * pixel_size, y);
-
-         for (pass=0; pass<npasses; ++pass)
-         {
-            /* The following two are for checking the macros: */
-            PNG_CONST png_uint_32 wPass = PNG_PASS_COLS(w, pass);
-
-            /* If do_interlace is set we don't call png_write_row for every
-             * row because some of them are empty.  In fact, for a 1x1 image,
-             * most of them are empty!
-             */
-            for (y=0; y<h; ++y)
-            {
-               png_const_bytep row = image[y];
-               png_byte tempRow[SIZE_ROWMAX];
-
-               /* If do_interlace *and* the image is interlaced we
-                * need a reduced interlace row; this may be reduced
-                * to empty.
-                */
-               if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
-               {
-                  /* The row must not be written if it doesn't exist, notice
-                   * that there are two conditions here, either the row isn't
-                   * ever in the pass or the row would be but isn't wide
-                   * enough to contribute any pixels.  In fact the wPass test
-                   * can be used to skip the whole y loop in this case.
-                   */
-                  if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
-                  {
-                     /* Set to all 1's for error detection (libpng tends to
-                      * set unset things to 0).
-                      */
-                     memset(tempRow, 0xff, sizeof tempRow);
-                     interlace_row(tempRow, row, pixel_size, w, pass);
-                     row = tempRow;
-                  }
-                  else
-                     continue;
-               }
-
-               /* Only get to here if the row has some pixels in it. */
-               png_write_row(pp, row);
-            }
-         }
-      }
-
-      png_write_end(pp, pi);
-
-      /* And store this under the appropriate id, then clean up. */
-      store_storefile(ps, id);
-
-      store_write_reset(ps);
-   }
-
-   Catch(fault)
-   {
-      /* Use the png_store returned by the exception. This may help the compiler
-       * because 'ps' is not used in this branch of the setjmp.  Note that fault
-       * and ps will always be the same value.
-       */
-      store_write_reset(fault);
-   }
-}
-
-static void
-make_size(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, int bdlo,
-    int PNG_CONST bdhi)
-{
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      png_uint_32 width;
-
-      for (width = 1; width <= 16; ++width)
-      {
-         png_uint_32 height;
-
-         for (height = 1; height <= 16; ++height)
-         {
-            /* The four combinations of DIY interlace and interlace or not -
-             * no interlace + DIY should be identical to no interlace with
-             * libpng doing it.
-             */
-            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
-               width, height, 0);
-            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
-               width, height, 1);
-            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
-               width, height, 0);
-            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
-               width, height, 1);
-         }
-      }
-   }
-}
-
-static void
-make_size_images(png_store *ps)
-{
-   /* This is in case of errors. */
-   safecat(ps->test, sizeof ps->test, 0, "make size images");
-
-   /* Arguments are colour_type, low bit depth, high bit depth
-    */
-   make_size(ps, 0, 0, WRITE_BDHI);
-   make_size(ps, 2, 3, WRITE_BDHI);
-   make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
-   make_size(ps, 4, 3, WRITE_BDHI);
-   make_size(ps, 6, 3, WRITE_BDHI);
-}
-
-/* Return a row based on image id and 'y' for checking: */
-static void
-standard_row(png_structp pp, png_byte std[STANDARD_ROWMAX], png_uint_32 id,
-   png_uint_32 y)
-{
-   if (WIDTH_FROM_ID(id) == 0)
-      transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
-   else
-      size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
-         DEPTH_FROM_ID(id)), y);
-}
-
-/* Tests - individual test cases */
-/* Like 'make_standard' but errors are deliberately introduced into the calls
- * to ensure that they get detected - it should not be possible to write an
- * invalid image with libpng!
- */
-#ifdef PNG_WARNINGS_SUPPORTED
-static void
-sBIT0_error_fn(png_structp pp, png_infop pi)
-{
-   /* 0 is invalid... */
-   png_color_8 bad;
-   bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
-   png_set_sBIT(pp, pi, &bad);
-}
-
-static void
-sBIT_error_fn(png_structp pp, png_infop pi)
-{
-   png_byte bit_depth;
-   png_color_8 bad;
-
-   if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
-      bit_depth = 8;
-
-   else
-      bit_depth = png_get_bit_depth(pp, pi);
-
-   /* Now we know the bit depth we can easily generate an invalid sBIT entry */
-   bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
-      (png_byte)(bit_depth+1);
-   png_set_sBIT(pp, pi, &bad);
-}
-
-static PNG_CONST struct
-{
-   void          (*fn)(png_structp, png_infop);
-   PNG_CONST char *msg;
-   unsigned int    warning :1; /* the error is a warning... */
-} error_test[] =
-    {
-       /* no warnings makes these errors undetectable. */
-       { sBIT0_error_fn, "sBIT(0): failed to detect error", 1 },
-       { sBIT_error_fn, "sBIT(too big): failed to detect error", 1 },
-    };
-
-static void
-make_error(png_store* volatile psIn, png_byte PNG_CONST colour_type,
-    png_byte bit_depth, int interlace_type, int test, png_const_charp name)
-{
-   png_store * volatile ps = psIn;
-
-   context(ps, fault);
-
-   Try
-   {
-      png_structp pp;
-      png_infop pi;
-
-      pp = set_store_for_write(ps, &pi, name);
-
-      if (pp == NULL)
-         Throw ps;
-
-      png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth),
-         transform_height(pp, colour_type, bit_depth), bit_depth, colour_type,
-         interlace_type, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
-      if (colour_type == 3) /* palette */
-         init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
-
-      /* Time for a few errors; these are in various optional chunks, the
-       * standard tests test the standard chunks pretty well.
-       */
-#     define exception__prev exception_prev_1
-#     define exception__env exception_env_1
-      Try
-      {
-         /* Expect this to throw: */
-         ps->expect_error = !error_test[test].warning;
-         ps->expect_warning = error_test[test].warning;
-         ps->saw_warning = 0;
-         error_test[test].fn(pp, pi);
-
-         /* Normally the error is only detected here: */
-         png_write_info(pp, pi);
-
-         /* And handle the case where it was only a warning: */
-         if (ps->expect_warning && ps->saw_warning)
-            Throw ps;
-
-         /* If we get here there is a problem, we have success - no error or
-          * no warning - when we shouldn't have success.  Log an error.
-          */
-         store_log(ps, pp, error_test[test].msg, 1 /*error*/);
-      }
-
-      Catch (fault)
-         ps = fault; /* expected exit, make sure ps is not clobbered */
-#undef exception__prev
-#undef exception__env
-
-      /* And clear these flags */
-      ps->expect_error = 0;
-      ps->expect_warning = 0;
-
-      /* Now write the whole image, just to make sure that the detected, or
-       * undetected, errro has not created problems inside libpng.
-       */
-      if (png_get_rowbytes(pp, pi) !=
-          transform_rowsize(pp, colour_type, bit_depth))
-         png_error(pp, "row size incorrect");
-
-      else
-      {
-         png_uint_32 h = transform_height(pp, colour_type, bit_depth);
-         int npasses = png_set_interlace_handling(pp);
-         int pass;
-
-         if (npasses != npasses_from_interlace_type(pp, interlace_type))
-            png_error(pp, "write: png_set_interlace_handling failed");
-
-         for (pass=0; pass<npasses; ++pass)
-         {
-            png_uint_32 y;
-
-            for (y=0; y<h; ++y)
-            {
-               png_byte buffer[TRANSFORM_ROWMAX];
-
-               transform_row(pp, buffer, colour_type, bit_depth, y);
-               png_write_row(pp, buffer);
-            }
-         }
-      }
-
-      png_write_end(pp, pi);
-
-      /* The following deletes the file that was just written. */
-      store_write_reset(ps);
-   }
-
-   Catch(fault)
-   {
-      store_write_reset(fault);
-   }
-}
-
-static int
-make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
-    int bdlo, int PNG_CONST bdhi)
-{
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      int interlace_type;
-
-      for (interlace_type = PNG_INTERLACE_NONE;
-           interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
-      {
-         unsigned int test;
-         char name[FILE_NAME_SIZE];
-
-         standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
-            interlace_type, 0, 0, 0);
-
-         for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test)
-         {
-            make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
-               test, name);
-
-            if (fail(pm))
-               return 0;
-         }
-      }
-   }
-
-   return 1; /* keep going */
-}
-#endif
-
-static void
-perform_error_test(png_modifier *pm)
-{
-#ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
-   /* Need to do this here because we just write in this test. */
-   safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
-
-   if (!make_errors(pm, 0, 0, WRITE_BDHI))
-      return;
-
-   if (!make_errors(pm, 2, 3, WRITE_BDHI))
-      return;
-
-   if (!make_errors(pm, 3, 0, 3))
-      return;
-
-   if (!make_errors(pm, 4, 3, WRITE_BDHI))
-      return;
-
-   if (!make_errors(pm, 6, 3, WRITE_BDHI))
-      return;
-#else
-   UNUSED(pm)
-#endif
-}
-
-/* This is just to validate the internal PNG formatting code - if this fails
- * then the warning messages the library outputs will probably be garbage.
- */
-static void
-perform_formatting_test(png_store *volatile ps)
-{
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-   /* The handle into the formatting code is the RFC1123 support; this test does
-    * nothing if that is compiled out.
-    */
-   context(ps, fault);
-
-   Try
-   {
-      png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
-      png_const_charp result;
-      png_structp pp;
-      png_time pt;
-
-      pp = set_store_for_write(ps, NULL, "libpng formatting test");
-
-      if (pp == NULL)
-         Throw ps;
-
-
-      /* Arbitrary settings: */
-      pt.year = 2079;
-      pt.month = 8;
-      pt.day = 29;
-      pt.hour = 13;
-      pt.minute = 53;
-      pt.second = 60; /* a leap second */
-
-      result = png_convert_to_rfc1123(pp, &pt);
-
-      if (result == NULL)
-         png_error(pp, "png_convert_to_rfc1123 failed");
-
-      if (strcmp(result, correct) != 0)
-      {
-         size_t pos = 0;
-         char msg[128];
-
-         pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
-         pos = safecat(msg, sizeof msg, pos, correct);
-         pos = safecat(msg, sizeof msg, pos, ") returned: '");
-         pos = safecat(msg, sizeof msg, pos, result);
-         pos = safecat(msg, sizeof msg, pos, "'");
-
-         png_error(pp, msg);
-      }
-
-      store_write_reset(ps);
-   }
-
-   Catch(fault)
-   {
-      store_write_reset(fault);
-   }
-#else
-   UNUSED(ps)
-#endif
-}
-
-/* Because we want to use the same code in both the progressive reader and the
- * sequential reader it is necessary to deal with the fact that the progressive
- * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
- * must contain all the test parameters and all the local variables directly
- * accessible to the sequential reader implementation.
- *
- * The technique adopted is to reinvent part of what Dijkstra termed a
- * 'display'; an array of pointers to the stack frames of enclosing functions so
- * that a nested function definition can access the local (C auto) variables of
- * the functions that contain its definition.  In fact C provides the first
- * pointer (the local variables - the stack frame pointer) and the last (the
- * global variables - the BCPL global vector typically implemented as global
- * addresses), this code requires one more pointer to make the display - the
- * local variables (and function call parameters) of the function that actually
- * invokes either the progressive or sequential reader.
- *
- * Perhaps confusingly this technique is confounded with classes - the
- * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
- * A gamma_display is a standard_display, taking advantage of the ANSI-C
- * requirement that the pointer to the first member of a structure must be the
- * same as the pointer to the structure.  This allows us to reuse standard_
- * functions in the gamma test code; something that could not be done with
- * nested functions!
- */
-typedef struct standard_display
-{
-   png_store*  ps;             /* Test parameters (passed to the function) */
-   png_byte    colour_type;
-   png_byte    bit_depth;
-   png_byte    red_sBIT;       /* Input data sBIT values. */
-   png_byte    green_sBIT;
-   png_byte    blue_sBIT;
-   png_byte    alpha_sBIT;
-   int         interlace_type;
-   png_uint_32 id;             /* Calculated file ID */
-   png_uint_32 w;              /* Width of image */
-   png_uint_32 h;              /* Height of image */
-   int         npasses;        /* Number of interlaced passes */
-   png_uint_32 pixel_size;     /* Width of one pixel in bits */
-   png_uint_32 bit_width;      /* Width of output row in bits */
-   size_t      cbRow;          /* Bytes in a row of the output image */
-   int         do_interlace;   /* Do interlacing internally */
-   int         is_transparent; /* Transparency information was present. */
-   int         speed;          /* Doing a speed test */
-   int         use_update_info;/* Call update_info, not start_image */
-   struct
-   {
-      png_uint_16 red;
-      png_uint_16 green;
-      png_uint_16 blue;
-   }           transparent;    /* The transparent color, if set. */
-   int         npalette;       /* Number of entries in the palette. */
-   store_palette
-               palette;
-} standard_display;
-
-static void
-standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
-   int do_interlace, int use_update_info)
-{
-   memset(dp, 0, sizeof *dp);
-
-   dp->ps = ps;
-   dp->colour_type = COL_FROM_ID(id);
-   dp->bit_depth = DEPTH_FROM_ID(id);
-   if (dp->bit_depth < 1 || dp->bit_depth > 16)
-      internal_error(ps, "internal: bad bit depth");
-   if (dp->colour_type == 3)
-      dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
-   else
-      dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
-         dp->bit_depth;
-   dp->interlace_type = INTERLACE_FROM_ID(id);
-   dp->id = id;
-   /* All the rest are filled in after the read_info: */
-   dp->w = 0;
-   dp->h = 0;
-   dp->npasses = 0;
-   dp->pixel_size = 0;
-   dp->bit_width = 0;
-   dp->cbRow = 0;
-   dp->do_interlace = do_interlace;
-   dp->is_transparent = 0;
-   dp->speed = ps->speed;
-   dp->use_update_info = use_update_info;
-   dp->npalette = 0;
-   /* Preset the transparent color to black: */
-   memset(&dp->transparent, 0, sizeof dp->transparent);
-   /* Preset the palette to full intensity/opaque througout: */
-   memset(dp->palette, 0xff, sizeof dp->palette);
-}
-
-/* Initialize the palette fields - this must be done later because the palette
- * comes from the particular png_store_file that is selected.
- */
-static void
-standard_palette_init(standard_display *dp)
-{
-   store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
-
-   /* The remaining entries remain white/opaque. */
-   if (dp->npalette > 0)
-   {
-      int i = dp->npalette;
-      memcpy(dp->palette, palette, i * sizeof *palette);
-
-      /* Check for a non-opaque palette entry: */
-      while (--i >= 0)
-         if (palette[i].alpha < 255)
-            break;
-
-#     ifdef __GNUC__
-         /* GCC can't handle the more obviously optimizable version. */
-         if (i >= 0)
-            dp->is_transparent = 1;
-         else
-            dp->is_transparent = 0;
-#     else
-         dp->is_transparent = (i >= 0);
-#     endif
-   }
-}
-
-/* Utility to read the palette from the PNG file and convert it into
- * store_palette format.  This returns 1 if there is any transparency in the
- * palette (it does not check for a transparent colour in the non-palette case.)
- */
-static int
-read_palette(store_palette palette, int *npalette, png_structp pp, png_infop pi)
-{
-   png_colorp pal;
-   png_bytep trans_alpha;
-   int num;
-
-   pal = 0;
-   *npalette = -1;
-
-   if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
-   {
-      int i = *npalette;
-
-      if (i <= 0 || i > 256)
-         png_error(pp, "validate: invalid PLTE count");
-
-      while (--i >= 0)
-      {
-         palette[i].red = pal[i].red;
-         palette[i].green = pal[i].green;
-         palette[i].blue = pal[i].blue;
-      }
-
-      /* Mark the remainder of the entries with a flag value (other than
-       * white/opaque which is the flag value stored above.)
-       */
-      memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
-   }
-
-   else /* !png_get_PLTE */
-   {
-      if (*npalette != (-1))
-         png_error(pp, "validate: invalid PLTE result");
-      /* But there is no palette, so record this: */
-      *npalette = 0;
-      memset(palette, 113, sizeof (store_palette));
-   }
-
-   trans_alpha = 0;
-   num = 2; /* force error below */
-   if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
-      (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
-      /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
-       * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
-       * so in the above call we get a success, we get a pointer (who knows what
-       * to) and we get num_trans == 0:
-       */
-      !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
-   {
-      int i;
-
-      /* Any of these are crash-worthy - given the implementation of
-       * png_get_tRNS up to 1.5 an app won't crash if it just checks the
-       * result above and fails to check that the variables it passed have
-       * actually been filled in!  Note that if the app were to pass the
-       * last, png_color_16p, variable too it couldn't rely on this.
-       */
-      if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
-         png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
-
-      for (i=0; i<num; ++i)
-         palette[i].alpha = trans_alpha[i];
-
-      for (num=*npalette; i<num; ++i)
-         palette[i].alpha = 255;
-
-      for (; i<256; ++i)
-         palette[i].alpha = 33; /* flag value */
-
-      return 1; /* transparency */
-   }
-
-   else
-   {
-      /* No palette transparency - just set the alpha channel to opaque. */
-      int i;
-
-      for (i=0, num=*npalette; i<num; ++i)
-         palette[i].alpha = 255;
-
-      for (; i<256; ++i)
-         palette[i].alpha = 55; /* flag value */
-
-      return 0; /* no transparency */
-   }
-}
-
-/* Utility to validate the palette if it should not have changed (the
- * non-transform case).
- */
-static void
-standard_palette_validate(standard_display *dp, png_structp pp, png_infop pi)
-{
-   int npalette;
-   store_palette palette;
-
-   if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
-      png_error(pp, "validate: palette transparency changed");
-
-   if (npalette != dp->npalette)
-   {
-      size_t pos = 0;
-      char msg[64];
-
-      pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
-      pos = safecatn(msg, sizeof msg, pos, dp->npalette);
-      pos = safecat(msg, sizeof msg, pos, " -> ");
-      pos = safecatn(msg, sizeof msg, pos, npalette);
-      png_error(pp, msg);
-   }
-
-   {
-      int i = npalette; /* npalette is aliased */
-
-      while (--i >= 0)
-         if (palette[i].red != dp->palette[i].red ||
-            palette[i].green != dp->palette[i].green ||
-            palette[i].blue != dp->palette[i].blue ||
-            palette[i].alpha != dp->palette[i].alpha)
-            png_error(pp, "validate: PLTE or tRNS chunk changed");
-   }
-}
-
-/* By passing a 'standard_display' the progressive callbacks can be used
- * directly by the sequential code, the functions suffixed "_imp" are the
- * implementations, the functions without the suffix are the callbacks.
- *
- * The code for the info callback is split into two because this callback calls
- * png_read_update_info or png_start_read_image and what gets called depends on
- * whether the info needs updating (we want to test both calls in pngvalid.)
- */
-static void
-standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
-{
-   if (png_get_bit_depth(pp, pi) != dp->bit_depth)
-      png_error(pp, "validate: bit depth changed");
-
-   if (png_get_color_type(pp, pi) != dp->colour_type)
-      png_error(pp, "validate: color type changed");
-
-   if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
-      png_error(pp, "validate: filter type changed");
-
-   if (png_get_interlace_type(pp, pi) != dp->interlace_type)
-      png_error(pp, "validate: interlacing changed");
-
-   if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
-      png_error(pp, "validate: compression type changed");
-
-   dp->w = png_get_image_width(pp, pi);
-
-   if (dp->w != standard_width(pp, dp->id))
-      png_error(pp, "validate: image width changed");
-
-   dp->h = png_get_image_height(pp, pi);
-
-   if (dp->h != standard_height(pp, dp->id))
-      png_error(pp, "validate: image height changed");
-
-   /* Record (but don't check at present) the input sBIT according to the colour
-    * type information.
-    */
-   {
-      png_color_8p sBIT = 0;
-
-      if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
-      {
-         int sBIT_invalid = 0;
-
-         if (sBIT == 0)
-            png_error(pp, "validate: unexpected png_get_sBIT result");
-
-         if (dp->colour_type & PNG_COLOR_MASK_COLOR)
-         {
-            if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->red_sBIT = sBIT->red;
-
-            if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->green_sBIT = sBIT->green;
-
-            if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->blue_sBIT = sBIT->blue;
-         }
-
-         else /* !COLOR */
-         {
-            if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
-         }
-
-         /* All 8 bits in tRNS for a palette image are significant - see the
-          * spec.
-          */
-         if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
-         {
-            if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->alpha_sBIT = sBIT->alpha;
-         }
-
-         if (sBIT_invalid)
-            png_error(pp, "validate: sBIT value out of range");
-      }
-   }
-
-   /* Important: this is validating the value *before* any transforms have been
-    * put in place.  It doesn't matter for the standard tests, where there are
-    * no transforms, but it does for other tests where rowbytes may change after
-    * png_read_update_info.
-    */
-   if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
-      png_error(pp, "validate: row size changed");
-
-   /* Validate the colour type 3 palette (this can be present on other color
-    * types.)
-    */
-   standard_palette_validate(dp, pp, pi);
-
-   /* In any case always check for a tranparent color (notice that the
-    * colour type 3 case must not give a successful return on the get_tRNS call
-    * with these arguments!)
-    */
-   {
-      png_color_16p trans_color = 0;
-
-      if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
-      {
-         if (trans_color == 0)
-            png_error(pp, "validate: unexpected png_get_tRNS (color) result");
-
-         switch (dp->colour_type)
-         {
-         case 0:
-            dp->transparent.red = dp->transparent.green = dp->transparent.blue =
-               trans_color->gray;
-            dp->is_transparent = 1;
-            break;
-
-         case 2:
-            dp->transparent.red = trans_color->red;
-            dp->transparent.green = trans_color->green;
-            dp->transparent.blue = trans_color->blue;
-            dp->is_transparent = 1;
-            break;
-
-         case 3:
-            /* Not expected because it should result in the array case
-             * above.
-             */
-            png_error(pp, "validate: unexpected png_get_tRNS result");
-            break;
-
-         default:
-            png_error(pp, "validate: invalid tRNS chunk with alpha image");
-         }
-      }
-   }
-
-   /* Read the number of passes - expected to match the value used when
-    * creating the image (interlaced or not).  This has the side effect of
-    * turning on interlace handling (if do_interlace is not set.)
-    */
-   dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
-   if (!dp->do_interlace && dp->npasses != png_set_interlace_handling(pp))
-      png_error(pp, "validate: file changed interlace type");
-
-   /* Caller calls png_read_update_info or png_start_read_image now, then calls
-    * part2.
-    */
-}
-
-/* This must be called *after* the png_read_update_info call to get the correct
- * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
- * image.
- */
-static void
-standard_info_part2(standard_display *dp, png_structp pp, png_infop pi,
-    int nImages)
-{
-   /* Record cbRow now that it can be found. */
-   dp->pixel_size = bit_size(pp, png_get_color_type(pp, pi),
-      png_get_bit_depth(pp, pi));
-   dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
-   dp->cbRow = png_get_rowbytes(pp, pi);
-
-   /* Validate the rowbytes here again. */
-   if (dp->cbRow != (dp->bit_width+7)/8)
-      png_error(pp, "bad png_get_rowbytes calculation");
-
-   /* Then ensure there is enough space for the output image(s). */
-   store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
-}
-
-static void
-standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
-    int nImages)
-{
-   /* Note that the validation routine has the side effect of turning on
-    * interlace handling in the subsequent code.
-    */
-   standard_info_part1(dp, pp, pi);
-
-   /* And the info callback has to call this (or png_read_update_info - see
-    * below in the png_modifier code for that variant.
-    */
-   if (dp->use_update_info)
-   {
-      /* For debugging the effect of multiple calls: */
-      int i = dp->use_update_info;
-      while (i-- > 0)
-         png_read_update_info(pp, pi);
-   }
-
-   else
-      png_start_read_image(pp);
-
-   /* Validate the height, width and rowbytes plus ensure that sufficient buffer
-    * exists for decoding the image.
-    */
-   standard_info_part2(dp, pp, pi, nImages);
-}
-
-static void
-standard_info(png_structp pp, png_infop pi)
-{
-   standard_display *dp = voidcast(standard_display*,
-      png_get_progressive_ptr(pp));
-
-   /* Call with nImages==1 because the progressive reader can only produce one
-    * image.
-    */
-   standard_info_imp(dp, pp, pi, 1 /*only one image*/);
-}
-
-static void
-progressive_row(png_structp pp, png_bytep new_row, png_uint_32 y, int pass)
-{
-   PNG_CONST standard_display *dp = voidcast(standard_display*,
-      png_get_progressive_ptr(pp));
-
-   /* When handling interlacing some rows will be absent in each pass, the
-    * callback still gets called, but with a NULL pointer.  This is checked
-    * in the 'else' clause below.  We need our own 'cbRow', but we can't call
-    * png_get_rowbytes because we got no info structure.
-    */
-   if (new_row != NULL)
-   {
-      png_bytep row;
-
-      /* In the case where the reader doesn't do the interlace it gives
-       * us the y in the sub-image:
-       */
-      if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
-      {
-#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
-         /* Use this opportunity to validate the png 'current' APIs: */
-         if (y != png_get_current_row_number(pp))
-            png_error(pp, "png_get_current_row_number is broken");
-
-         if (pass != png_get_current_pass_number(pp))
-            png_error(pp, "png_get_current_pass_number is broken");
-#endif
-
-         y = PNG_ROW_FROM_PASS_ROW(y, pass);
-      }
-
-      /* Validate this just in case. */
-      if (y >= dp->h)
-         png_error(pp, "invalid y to progressive row callback");
-
-      row = store_image_row(dp->ps, pp, 0, y);
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-      /* Combine the new row into the old: */
-      if (dp->do_interlace)
-      {
-         if (dp->interlace_type == PNG_INTERLACE_ADAM7)
-            deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass);
-         else
-            row_copy(row, new_row, dp->pixel_size * dp->w);
-      }
-      else
-         png_progressive_combine_row(pp, row, new_row);
-   } else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
-      PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
-      PNG_PASS_COLS(dp->w, pass) > 0)
-      png_error(pp, "missing row in progressive de-interlacing");
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-}
-
-static void
-sequential_row(standard_display *dp, png_structp pp, png_infop pi,
-    PNG_CONST int iImage, PNG_CONST int iDisplay)
-{
-   PNG_CONST int         npasses = dp->npasses;
-   PNG_CONST int         do_interlace = dp->do_interlace &&
-      dp->interlace_type == PNG_INTERLACE_ADAM7;
-   PNG_CONST png_uint_32 height = standard_height(pp, dp->id);
-   PNG_CONST png_uint_32 width = standard_width(pp, dp->id);
-   PNG_CONST png_store*  ps = dp->ps;
-   int pass;
-
-   for (pass=0; pass<npasses; ++pass)
-   {
-      png_uint_32 y;
-      png_uint_32 wPass = PNG_PASS_COLS(width, pass);
-
-      for (y=0; y<height; ++y)
-      {
-         if (do_interlace)
-         {
-            /* wPass may be zero or this row may not be in this pass.
-             * png_read_row must not be called in either case.
-             */
-            if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
-            {
-               /* Read the row into a pair of temporary buffers, then do the
-                * merge here into the output rows.
-                */
-               png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
-
-               /* The following aids (to some extent) error detection - we can
-                * see where png_read_row wrote.  Use opposite values in row and
-                * display to make this easier.  Don't use 0xff (which is used in
-                * the image write code to fill unused bits) or 0 (which is a
-                * likely value to overwrite unused bits with).
-                */
-               memset(row, 0xc5, sizeof row);
-               memset(display, 0x5c, sizeof display);
-
-               png_read_row(pp, row, display);
-
-               if (iImage >= 0)
-                  deinterlace_row(store_image_row(ps, pp, iImage, y), row,
-                     dp->pixel_size, dp->w, pass);
-
-               if (iDisplay >= 0)
-                  deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
-                     dp->pixel_size, dp->w, pass);
-            }
-         }
-         else
-            png_read_row(pp,
-               iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
-               iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
-      }
-   }
-
-   /* And finish the read operation (only really necessary if the caller wants
-    * to find additional data in png_info from chunks after the last IDAT.)
-    */
-   png_read_end(pp, pi);
-}
-
-static void
-standard_row_validate(standard_display *dp, png_structp pp,
-   int iImage, int iDisplay, png_uint_32 y)
-{
-   int where;
-   png_byte std[STANDARD_ROWMAX];
-
-   /* The row must be pre-initialized to the magic number here for the size
-    * tests to pass:
-    */
-   memset(std, 178, sizeof std);
-   standard_row(pp, std, dp->id, y);
-
-   /* At the end both the 'row' and 'display' arrays should end up identical.
-    * In earlier passes 'row' will be partially filled in, with only the pixels
-    * that have been read so far, but 'display' will have those pixels
-    * replicated to fill the unread pixels while reading an interlaced image.
-#if PNG_LIBPNG_VER < 10506
-    * The side effect inside the libpng sequential reader is that the 'row'
-    * array retains the correct values for unwritten pixels within the row
-    * bytes, while the 'display' array gets bits off the end of the image (in
-    * the last byte) trashed.  Unfortunately in the progressive reader the
-    * row bytes are always trashed, so we always do a pixel_cmp here even though
-    * a memcmp of all cbRow bytes will succeed for the sequential reader.
-#endif
-    */
-   if (iImage >= 0 &&
-      (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
-            dp->bit_width)) != 0)
-   {
-      char msg[64];
-      sprintf(msg, "PNG image row[%d][%d] changed from %.2x to %.2x", y,
-         where-1, std[where-1],
-         store_image_row(dp->ps, pp, iImage, y)[where-1]);
-      png_error(pp, msg);
-   }
-
-#if PNG_LIBPNG_VER < 10506
-   /* In this case use pixel_cmp because we need to compare a partial
-    * byte at the end of the row if the row is not an exact multiple
-    * of 8 bits wide.  (This is fixed in libpng-1.5.6 and pixel_cmp is
-    * changed to match!)
-    */
-#endif
-   if (iDisplay >= 0 &&
-      (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
-         dp->bit_width)) != 0)
-   {
-      char msg[64];
-      sprintf(msg, "display  row[%d][%d] changed from %.2x to %.2x", y,
-         where-1, std[where-1],
-         store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
-      png_error(pp, msg);
-   }
-}
-
-static void
-standard_image_validate(standard_display *dp, png_structp pp, int iImage,
-    int iDisplay)
-{
-   png_uint_32 y;
-
-   if (iImage >= 0)
-      store_image_check(dp->ps, pp, iImage);
-
-   if (iDisplay >= 0)
-      store_image_check(dp->ps, pp, iDisplay);
-
-   for (y=0; y<dp->h; ++y)
-      standard_row_validate(dp, pp, iImage, iDisplay, y);
-
-   /* This avoids false positives if the validation code is never called! */
-   dp->ps->validated = 1;
-}
-
-static void
-standard_end(png_structp pp, png_infop pi)
-{
-   standard_display *dp = voidcast(standard_display*,
-      png_get_progressive_ptr(pp));
-
-   UNUSED(pi)
-
-   /* Validate the image - progressive reading only produces one variant for
-    * interlaced images.
-    */
-   standard_image_validate(dp, pp, 0, -1);
-}
-
-/* A single test run checking the standard image to ensure it is not damaged. */
-static void
-standard_test(png_store* PNG_CONST psIn, png_uint_32 PNG_CONST id,
-   int do_interlace, int use_update_info)
-{
-   standard_display d;
-   context(psIn, fault);
-
-   /* Set up the display (stack frame) variables from the arguments to the
-    * function and initialize the locals that are filled in later.
-    */
-   standard_display_init(&d, psIn, id, do_interlace, use_update_info);
-
-   /* Everything is protected by a Try/Catch.  The functions called also
-    * typically have local Try/Catch blocks.
-    */
-   Try
-   {
-      png_structp pp;
-      png_infop pi;
-
-      /* Get a png_struct for reading the image. This will throw an error if it
-       * fails, so we don't need to check the result.
-       */
-      pp = set_store_for_read(d.ps, &pi, d.id,
-         d.do_interlace ?  (d.ps->progressive ?
-            "pngvalid progressive deinterlacer" :
-            "pngvalid sequential deinterlacer") : (d.ps->progressive ?
-               "progressive reader" : "sequential reader"));
-
-      /* Initialize the palette correctly from the png_store_file. */
-      standard_palette_init(&d);
-
-      /* Introduce the correct read function. */
-      if (d.ps->progressive)
-      {
-         png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
-            standard_end);
-
-         /* Now feed data into the reader until we reach the end: */
-         store_progressive_read(d.ps, pp, pi);
-      }
-      else
-      {
-         /* Note that this takes the store, not the display. */
-         png_set_read_fn(pp, d.ps, store_read);
-
-         /* Check the header values: */
-         png_read_info(pp, pi);
-
-         /* The code tests both versions of the images that the sequential
-          * reader can produce.
-          */
-         standard_info_imp(&d, pp, pi, 2 /*images*/);
-
-         /* Need the total bytes in the image below; we can't get to this point
-          * unless the PNG file values have been checked against the expected
-          * values.
-          */
-         {
-            sequential_row(&d, pp, pi, 0, 1);
-
-            /* After the last pass loop over the rows again to check that the
-             * image is correct.
-             */
-            if (!d.speed)
-               standard_image_validate(&d, pp, 0, 1);
-            else
-               d.ps->validated = 1;
-         }
-      }
-
-      /* Check for validation. */
-      if (!d.ps->validated)
-         png_error(pp, "image read failed silently");
-
-      /* Successful completion. */
-   }
-
-   Catch(fault)
-      d.ps = fault; /* make sure this hasn't been clobbered. */
-
-   /* In either case clean up the store. */
-   store_read_reset(d.ps);
-}
-
-static int
-test_standard(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
-    int bdlo, int PNG_CONST bdhi)
-{
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      int interlace_type;
-
-      for (interlace_type = PNG_INTERLACE_NONE;
-           interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
-      {
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
-            interlace_type, 0, 0, 0), 0/*do_interlace*/, pm->use_update_info);
-
-         if (fail(pm))
-            return 0;
-      }
-   }
-
-   return 1; /* keep going */
-}
-
-static void
-perform_standard_test(png_modifier *pm)
-{
-   /* Test each colour type over the valid range of bit depths (expressed as
-    * log2(bit_depth) in turn, stop as soon as any error is detected.
-    */
-   if (!test_standard(pm, 0, 0, READ_BDHI))
-      return;
-
-   if (!test_standard(pm, 2, 3, READ_BDHI))
-      return;
-
-   if (!test_standard(pm, 3, 0, 3))
-      return;
-
-   if (!test_standard(pm, 4, 3, READ_BDHI))
-      return;
-
-   if (!test_standard(pm, 6, 3, READ_BDHI))
-      return;
-}
-
-
-/********************************** SIZE TESTS ********************************/
-static int
-test_size(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
-    int bdlo, int PNG_CONST bdhi)
-{
-   /* Run the tests on each combination.
-    *
-    * NOTE: on my 32 bit x86 each of the following blocks takes
-    * a total of 3.5 seconds if done across every combo of bit depth
-    * width and height.  This is a waste of time in practice, hence the
-    * hinc and winc stuff:
-    */
-   static PNG_CONST png_byte hinc[] = {1, 3, 11, 1, 5};
-   static PNG_CONST png_byte winc[] = {1, 9, 5, 7, 1};
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      png_uint_32 h, w;
-
-      for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
-      {
-         /* First test all the 'size' images against the sequential
-          * reader using libpng to deinterlace (where required.)  This
-          * validates the write side of libpng.  There are four possibilities
-          * to validate.
-          */
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
-            PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
-            pm->use_update_info);
-
-         if (fail(pm))
-            return 0;
-
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
-            PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
-            pm->use_update_info);
-
-         if (fail(pm))
-            return 0;
-
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
-            PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
-            pm->use_update_info);
-
-         if (fail(pm))
-            return 0;
-
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
-            PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
-            pm->use_update_info);
-
-         if (fail(pm))
-            return 0;
-
-         /* Now validate the interlaced read side - do_interlace true,
-          * in the progressive case this does actually make a difference
-          * to the code used in the non-interlaced case too.
-          */
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
-            PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
-            pm->use_update_info);
-
-         if (fail(pm))
-            return 0;
-
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
-            PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
-            pm->use_update_info);
-
-         if (fail(pm))
-            return 0;
-      }
-   }
-
-   return 1; /* keep going */
-}
-
-static void
-perform_size_test(png_modifier *pm)
-{
-   /* Test each colour type over the valid range of bit depths (expressed as
-    * log2(bit_depth) in turn, stop as soon as any error is detected.
-    */
-   if (!test_size(pm, 0, 0, READ_BDHI))
-      return;
-
-   if (!test_size(pm, 2, 3, READ_BDHI))
-      return;
-
-   /* For the moment don't do the palette test - it's a waste of time when
-    * compared to the grayscale test.
-    */
-#if 0
-   if (!test_size(pm, 3, 0, 3))
-      return;
-#endif
-
-   if (!test_size(pm, 4, 3, READ_BDHI))
-      return;
-
-   if (!test_size(pm, 6, 3, READ_BDHI))
-      return;
-}
-
-
-/******************************* TRANSFORM TESTS ******************************/
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-/* A set of tests to validate libpng image transforms.  The possibilities here
- * are legion because the transforms can be combined in a combinatorial
- * fashion.  To deal with this some measure of restraint is required, otherwise
- * the tests would take forever.
- */
-typedef struct image_pixel
-{
-   /* A local (pngvalid) representation of a PNG pixel, in all its
-    * various forms.
-    */
-   unsigned int red, green, blue, alpha; /* For non-palette images. */
-   unsigned int palette_index;           /* For a palette image. */
-   png_byte colour_type;                 /* As in the spec. */
-   png_byte bit_depth;                   /* Defines bit size in row */
-   png_byte sample_depth;                /* Scale of samples */
-   int      have_tRNS;                   /* tRNS chunk may need processing */
-
-   /* For checking the code calculates double precision floating point values
-    * along with an error value, accumulated from the transforms.  Because an
-    * sBIT setting allows larger error bounds (indeed, by the spec, apparently
-    * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
-    * channel is stored.  This sBIT value is folded in to the stored error value
-    * at the end of the application of the transforms to the pixel.
-    */
-   double   redf, greenf, bluef, alphaf;
-   double   rede, greene, bluee, alphae;
-   png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
-} image_pixel;
-
-/* Shared utility function, see below. */
-static void
-image_pixel_setf(image_pixel *this, unsigned int max)
-{
-   this->redf = this->red / (double)max;
-   this->greenf = this->green / (double)max;
-   this->bluef = this->blue / (double)max;
-   this->alphaf = this->alpha / (double)max;
-
-   if (this->red < max)
-      this->rede = this->redf * DBL_EPSILON;
-   else
-      this->rede = 0;
-   if (this->green < max)
-      this->greene = this->greenf * DBL_EPSILON;
-   else
-      this->greene = 0;
-   if (this->blue < max)
-      this->bluee = this->bluef * DBL_EPSILON;
-   else
-      this->bluee = 0;
-   if (this->alpha < max)
-      this->alphae = this->alphaf * DBL_EPSILON;
-   else
-      this->alphae = 0;
-}
-
-/* Initialize the structure for the next pixel - call this before doing any
- * transforms and call it for each pixel since all the fields may need to be
- * reset.
- */
-static void
-image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
-    png_byte bit_depth, png_uint_32 x, store_palette palette)
-{
-   PNG_CONST png_byte sample_depth = (png_byte)(colour_type ==
-      PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
-   PNG_CONST unsigned int max = (1U<<sample_depth)-1;
-
-   /* Initially just set everything to the same number and the alpha to opaque.
-    * Note that this currently assumes a simple palette where entry x has colour
-    * rgb(x,x,x)!
-    */
-   this->palette_index = this->red = this->green = this->blue =
-      sample(row, colour_type, bit_depth, x, 0);
-   this->alpha = max;
-   this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
-      sample_depth;
-
-   /* Then override as appropriate: */
-   if (colour_type == 3) /* palette */
-   {
-      /* This permits the caller to default to the sample value. */
-      if (palette != 0)
-      {
-         PNG_CONST unsigned int i = this->palette_index;
-
-         this->red = palette[i].red;
-         this->green = palette[i].green;
-         this->blue = palette[i].blue;
-         this->alpha = palette[i].alpha;
-      }
-   }
-
-   else /* not palette */
-   {
-      unsigned int i = 0;
-
-      if (colour_type & 2)
-      {
-         this->green = sample(row, colour_type, bit_depth, x, 1);
-         this->blue = sample(row, colour_type, bit_depth, x, 2);
-         i = 2;
-      }
-      if (colour_type & 4)
-         this->alpha = sample(row, colour_type, bit_depth, x, ++i);
-   }
-
-   /* Calculate the scaled values, these are simply the values divided by
-    * 'max' and the error is initialized to the double precision epsilon value
-    * from the header file.
-    */
-   image_pixel_setf(this, max);
-
-   /* Store the input information for use in the transforms - these will
-    * modify the information.
-    */
-   this->colour_type = colour_type;
-   this->bit_depth = bit_depth;
-   this->sample_depth = sample_depth;
-   this->have_tRNS = 0;
-}
-
-/* Convert a palette image to an rgb image.  This necessarily converts the tRNS
- * chunk at the same time, because the tRNS will be in palette form.  The way
- * palette validation works means that the original palette is never updated,
- * instead the image_pixel value from the row contains the RGB of the
- * corresponding palette entry and *this* is updated.  Consequently this routine
- * only needs to change the colour type information.
- */
-static void
-image_pixel_convert_PLTE(image_pixel *this)
-{
-   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      if (this->have_tRNS)
-      {
-         this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
-         this->have_tRNS = 0;
-      }
-      else
-         this->colour_type = PNG_COLOR_TYPE_RGB;
-
-      /* The bit depth of the row changes at this point too (notice that this is
-       * the row format, not the sample depth, which is separate.)
-       */
-      this->bit_depth = 8;
-   }
-}
-
-/* Add an alpha channel; this will import the tRNS information because tRNS is
- * not valid in an alpha image.  The bit depth will invariably be set to at
- * least 8.  Palette images will be converted to alpha (using the above API).
- */
-static void
-image_pixel_add_alpha(image_pixel *this, PNG_CONST standard_display *display)
-{
-   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
-      image_pixel_convert_PLTE(this);
-
-   if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
-   {
-      if (this->colour_type == PNG_COLOR_TYPE_GRAY)
-      {
-         if (this->bit_depth < 8)
-            this->bit_depth = 8;
-
-         if (this->have_tRNS)
-         {
-            this->have_tRNS = 0;
-
-            /* Check the input, original, channel value here against the
-             * original tRNS gray chunk valie.
-             */
-            if (this->red == display->transparent.red)
-               this->alphaf = 0;
-            else
-               this->alphaf = 1;
-         }
-         else
-            this->alphaf = 1;
-
-         this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
-      }
-
-      else if (this->colour_type == PNG_COLOR_TYPE_RGB)
-      {
-         if (this->have_tRNS)
-         {
-            this->have_tRNS = 0;
-
-            /* Again, check the exact input values, not the current transformed
-             * value!
-             */
-            if (this->red == display->transparent.red &&
-               this->green == display->transparent.green &&
-               this->blue == display->transparent.blue)
-               this->alphaf = 0;
-            else
-               this->alphaf = 1;
-
-            this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
-         }
-      }
-
-      /* The error in the alpha is zero and the sBIT value comes from the
-       * original sBIT data (actually it will always be the original bit depth).
-       */
-      this->alphae = 0;
-      this->alpha_sBIT = display->alpha_sBIT;
-   }
-}
-
-struct transform_display;
-typedef struct image_transform
-{
-   /* The name of this transform: a string. */
-   PNG_CONST char *name;
-
-   /* Each transform can be disabled from the command line: */
-   int enable;
-
-   /* The global list of transforms; read only. */
-   struct image_transform *PNG_CONST list;
-
-   /* The global count of the number of times this transform has been set on an
-    * image.
-    */
-   unsigned int global_use;
-
-   /* The local count of the number of times this transform has been set. */
-   unsigned int local_use;
-
-   /* The next transform in the list, each transform must call its own next
-    * transform after it has processed the pixel successfully.
-    */
-   PNG_CONST struct image_transform *next;
-
-   /* A single transform for the image, expressed as a series of function
-    * callbacks and some space for values.
-    *
-    * First a callback to add any required modifications to the png_modifier;
-    * this gets called just before the modifier is set up for read.
-    */
-   void (*ini)(PNG_CONST struct image_transform *this,
-      struct transform_display *that);
-
-   /* And a callback to set the transform on the current png_read_struct:
-    */
-   void (*set)(PNG_CONST struct image_transform *this,
-      struct transform_display *that, png_structp pp, png_infop pi);
-
-   /* Then a transform that takes an input pixel in one PNG format or another
-    * and modifies it by a pngvalid implementation of the transform (thus
-    * duplicating the libpng intent without, we hope, duplicating the bugs
-    * in the libpng implementation!)  The png_structp is solely to allow error
-    * reporting via png_error and png_warning.
-    */
-   void (*mod)(PNG_CONST struct image_transform *this, image_pixel *that,
-      png_structp pp, PNG_CONST struct transform_display *display);
-
-   /* Add this transform to the list and return true if the transform is
-    * meaningful for this colour type and bit depth - if false then the
-    * transform should have no effect on the image so there's not a lot of
-    * point running it.
-    */
-   int (*add)(struct image_transform *this,
-      PNG_CONST struct image_transform **that, png_byte colour_type,
-      png_byte bit_depth);
-} image_transform;
-
-typedef struct transform_display
-{
-   standard_display this;
-
-   /* Parameters */
-   png_modifier*              pm;
-   PNG_CONST image_transform* transform_list;
-
-   /* Local variables */
-   png_byte output_colour_type;
-   png_byte output_bit_depth;
-
-   /* Modifications (not necessarily used.) */
-   gama_modification gama_mod;
-   chrm_modification chrm_mod;
-   srgb_modification srgb_mod;
-} transform_display;
-
-/* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
-static void
-transform_set_encoding(transform_display *this)
-{
-   /* Set up the png_modifier '_current' fields then use these to determine how
-    * to add appropriate chunks.
-    */
-   png_modifier *pm = this->pm;
-
-   modifier_set_encoding(pm);
-
-   if (modifier_color_encoding_is_set(pm))
-   {
-      if (modifier_color_encoding_is_sRGB(pm))
-         srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
-
-      else
-      {
-         /* Set gAMA and cHRM separately. */
-         gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
-
-         if (pm->current_encoding != 0)
-            chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
-      }
-   }
-}
-
-/* Three functions to end the list: */
-static void
-image_transform_ini_end(PNG_CONST image_transform *this,
-   transform_display *that)
-{
-   UNUSED(this)
-   UNUSED(that)
-}
-
-static void
-image_transform_set_end(PNG_CONST image_transform *this,
-   transform_display *that, png_structp pp, png_infop pi)
-{
-   UNUSED(this)
-   UNUSED(that)
-   UNUSED(pp)
-   UNUSED(pi)
-}
-
-/* At the end of the list recalculate the output image pixel value from the
- * double precision values set up by the preceding 'mod' calls:
- */
-static unsigned int
-sample_scale(double sample_value, unsigned int scale)
-{
-   sample_value = floor(sample_value * scale + .5);
-
-   /* Return NaN as 0: */
-   if (!(sample_value > 0))
-      sample_value = 0;
-   else if (sample_value > scale)
-      sample_value = scale;
-
-   return (unsigned int)sample_value;
-}
-
-static void
-image_transform_mod_end(PNG_CONST image_transform *this, image_pixel *that,
-    png_structp pp, PNG_CONST transform_display *display)
-{
-   PNG_CONST unsigned int scale = (1U<<that->sample_depth)-1;
-
-   UNUSED(this)
-   UNUSED(pp)
-   UNUSED(display)
-
-   /* At the end recalculate the digitized red green and blue values according
-    * to the current sample_depth of the pixel.
-    *
-    * The sample value is simply scaled to the maximum, checking for over
-    * and underflow (which can both happen for some image transforms,
-    * including simple size scaling, though libpng doesn't do that at present.
-    */
-   that->red = sample_scale(that->redf, scale);
-
-   /* The error value is increased, at the end, according to the lowest sBIT
-    * value seen.  Common sense tells us that the intermediate integer
-    * representations are no more accurate than +/- 0.5 in the integral values,
-    * the sBIT allows the implementation to be worse than this.  In addition the
-    * PNG specification actually permits any error within the range (-1..+1),
-    * but that is ignored here.  Instead the final digitized value is compared,
-    * below to the digitized value of the error limits - this has the net effect
-    * of allowing (almost) +/-1 in the output value.  It's difficult to see how
-    * any algorithm that digitizes intermediate results can be more accurate.
-    */
-   that->rede += 1./(2*((1U<<that->red_sBIT)-1));
-
-   if (that->colour_type & PNG_COLOR_MASK_COLOR)
-   {
-      that->green = sample_scale(that->greenf, scale);
-      that->blue = sample_scale(that->bluef, scale);
-      that->greene += 1./(2*((1U<<that->green_sBIT)-1));
-      that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
-   }
-   else
-   {
-      that->blue = that->green = that->red;
-      that->bluef = that->greenf = that->redf;
-      that->bluee = that->greene = that->rede;
-   }
-
-   if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
-      that->colour_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      that->alpha = sample_scale(that->alphaf, scale);
-      that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
-   }
-   else
-   {
-      that->alpha = scale; /* opaque */
-      that->alpha = 1;     /* Override this. */
-      that->alphae = 0;    /* It's exact ;-) */
-   }
-}
-
-/* Static 'end' structure: */
-static image_transform image_transform_end =
-{
-   "(end)", /* name */
-   1, /* enable */
-   0, /* list */
-   0, /* global_use */
-   0, /* local_use */
-   0, /* next */
-   image_transform_ini_end,
-   image_transform_set_end,
-   image_transform_mod_end,
-   0 /* never called, I want it to crash if it is! */
-};
-
-/* Reader callbacks and implementations, where they differ from the standard
- * ones.
- */
-static void
-transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
-    PNG_CONST image_transform *transform_list)
-{
-   memset(dp, 0, sizeof *dp);
-
-   /* Standard fields */
-   standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
-      pm->use_update_info);
-
-   /* Parameter fields */
-   dp->pm = pm;
-   dp->transform_list = transform_list;
-
-   /* Local variable fields */
-   dp->output_colour_type = 255; /* invalid */
-   dp->output_bit_depth = 255;  /* invalid */
-}
-
-static void
-transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
-{
-   /* Reuse the standard stuff as appropriate. */
-   standard_info_part1(&dp->this, pp, pi);
-
-   /* Now set the list of transforms. */
-   dp->transform_list->set(dp->transform_list, dp, pp, pi);
-
-   /* Update the info structure for these transforms: */
-   {
-      int i = dp->this.use_update_info;
-      /* Always do one call, even if use_update_info is 0. */
-      do
-         png_read_update_info(pp, pi);
-      while (--i > 0);
-   }
-
-   /* And get the output information into the standard_display */
-   standard_info_part2(&dp->this, pp, pi, 1/*images*/);
-
-   /* Plus the extra stuff we need for the transform tests: */
-   dp->output_colour_type = png_get_color_type(pp, pi);
-   dp->output_bit_depth = png_get_bit_depth(pp, pi);
-
-   /* Validate the combination of colour type and bit depth that we are getting
-    * out of libpng; the semantics of something not in the PNG spec are, at
-    * best, unclear.
-    */
-   switch (dp->output_colour_type)
-   {
-   case PNG_COLOR_TYPE_PALETTE:
-      if (dp->output_bit_depth > 8) goto error;
-      /*FALL THROUGH*/
-   case PNG_COLOR_TYPE_GRAY:
-      if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
-         dp->output_bit_depth == 4)
-         break;
-      /*FALL THROUGH*/
-   default:
-      if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
-         break;
-      /*FALL THROUGH*/
-   error:
-      {
-         char message[128];
-         size_t pos;
-
-         pos = safecat(message, sizeof message, 0,
-            "invalid final bit depth: colour type(");
-         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
-         pos = safecat(message, sizeof message, pos, ") with bit depth: ");
-         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
-
-         png_error(pp, message);
-      }
-   }
-
-   /* Use a test pixel to check that the output agrees with what we expect -
-    * this avoids running the whole test if the output is unexpected.
-    */
-   {
-      image_pixel test_pixel;
-
-      memset(&test_pixel, 0, sizeof test_pixel);
-      test_pixel.colour_type = dp->this.colour_type; /* input */
-      test_pixel.bit_depth = dp->this.bit_depth;
-      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
-         test_pixel.sample_depth = 8;
-      else
-         test_pixel.sample_depth = test_pixel.bit_depth;
-      /* Don't need sBIT here, but it must be set to non-zero to avoid
-       * arithmetic overflows.
-       */
-      test_pixel.have_tRNS = dp->this.is_transparent;
-      test_pixel.red_sBIT = test_pixel.green_sBIT = test_pixel.blue_sBIT =
-         test_pixel.alpha_sBIT = test_pixel.sample_depth;
-
-      dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
-
-      if (test_pixel.colour_type != dp->output_colour_type)
-      {
-         char message[128];
-         size_t pos = safecat(message, sizeof message, 0, "colour type ");
-
-         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
-         pos = safecat(message, sizeof message, pos, " expected ");
-         pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
-
-         png_error(pp, message);
-      }
-
-      if (test_pixel.bit_depth != dp->output_bit_depth)
-      {
-         char message[128];
-         size_t pos = safecat(message, sizeof message, 0, "bit depth ");
-
-         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
-         pos = safecat(message, sizeof message, pos, " expected ");
-         pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
-
-         png_error(pp, message);
-      }
-
-      /* If both bit depth and colour type are correct check the sample depth.
-       * I believe these are both internal errors.
-       */
-      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         if (test_pixel.sample_depth != 8) /* oops - internal error! */
-            png_error(pp, "pngvalid: internal: palette sample depth not 8");
-      }
-      else if (test_pixel.sample_depth != dp->output_bit_depth)
-      {
-         char message[128];
-         size_t pos = safecat(message, sizeof message, 0,
-            "internal: sample depth ");
-
-         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
-         pos = safecat(message, sizeof message, pos, " expected ");
-         pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
-
-         png_error(pp, message);
-      }
-   }
-}
-
-static void
-transform_info(png_structp pp, png_infop pi)
-{
-   transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
-      pp, pi);
-}
-
-static void
-transform_range_check(png_structp pp, unsigned int r, unsigned int g,
-   unsigned int b, unsigned int a, unsigned int in_digitized, double in,
-   unsigned int out, png_byte sample_depth, double err, double limit,
-   PNG_CONST char *name, double digitization_error)
-{
-   /* Compare the scaled, digitzed, values of our local calculation (in+-err)
-    * with the digitized values libpng produced;  'sample_depth' is the actual
-    * digitization depth of the libpng output colors (the bit depth except for
-    * palette images where it is always 8.)  The check on 'err' is to detect
-    * internal errors in pngvalid itself.
-    */
-   unsigned int max = (1U<<sample_depth)-1;
-   double in_min = ceil((in-err)*max - digitization_error);
-   double in_max = floor((in+err)*max + digitization_error);
-   if (err > limit || !(out >= in_min && out <= in_max))
-   {
-      char message[256];
-      size_t pos;
-
-      pos = safecat(message, sizeof message, 0, name);
-      pos = safecat(message, sizeof message, pos, " output value error: rgba(");
-      pos = safecatn(message, sizeof message, pos, r);
-      pos = safecat(message, sizeof message, pos, ",");
-      pos = safecatn(message, sizeof message, pos, g);
-      pos = safecat(message, sizeof message, pos, ",");
-      pos = safecatn(message, sizeof message, pos, b);
-      pos = safecat(message, sizeof message, pos, ",");
-      pos = safecatn(message, sizeof message, pos, a);
-      pos = safecat(message, sizeof message, pos, "): ");
-      pos = safecatn(message, sizeof message, pos, out);
-      pos = safecat(message, sizeof message, pos, " expected: ");
-      pos = safecatn(message, sizeof message, pos, in_digitized);
-      pos = safecat(message, sizeof message, pos, " (");
-      pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
-      pos = safecat(message, sizeof message, pos, "..");
-      pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
-      pos = safecat(message, sizeof message, pos, ")");
-
-      png_error(pp, message);
-   }
-}
-
-static void
-transform_image_validate(transform_display *dp, png_structp pp, png_infop pi)
-{
-   /* Constants for the loop below: */
-   PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
-   PNG_CONST png_byte in_ct = dp->this.colour_type;
-   PNG_CONST png_byte in_bd = dp->this.bit_depth;
-   PNG_CONST png_uint_32 w = dp->this.w;
-   PNG_CONST png_uint_32 h = dp->this.h;
-   PNG_CONST png_byte out_ct = dp->output_colour_type;
-   PNG_CONST png_byte out_bd = dp->output_bit_depth;
-   PNG_CONST png_byte sample_depth = (png_byte)(out_ct ==
-      PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
-   PNG_CONST png_byte red_sBIT = dp->this.red_sBIT;
-   PNG_CONST png_byte green_sBIT = dp->this.green_sBIT;
-   PNG_CONST png_byte blue_sBIT = dp->this.blue_sBIT;
-   PNG_CONST png_byte alpha_sBIT = dp->this.alpha_sBIT;
-   PNG_CONST int have_tRNS = dp->this.is_transparent;
-   double digitization_error;
-
-   store_palette out_palette;
-   png_uint_32 y;
-
-   UNUSED(pi)
-
-   /* Check for row overwrite errors */
-   store_image_check(dp->this.ps, pp, 0);
-
-   /* Read the palette corresponding to the output if the output colour type
-    * indicates a palette, othewise set out_palette to garbage.
-    */
-   if (out_ct == PNG_COLOR_TYPE_PALETTE)
-   {
-      /* Validate that the palette count itself has not changed - this is not
-       * expected.
-       */
-      int npalette = (-1);
-
-      (void)read_palette(out_palette, &npalette, pp, pi);
-      if (npalette != dp->this.npalette)
-         png_error(pp, "unexpected change in palette size");
-
-      digitization_error = .5;
-   }
-   else
-   {
-      png_byte in_sample_depth;
-
-      memset(out_palette, 0x5e, sizeof out_palette);
-
-      /* assume-8-bit-calculations means assume that if the input has 8 bit
-       * (or less) samples and the output has 16 bit samples the calculations
-       * will be done with 8 bit precision, not 16.
-       *
-       * TODO: fix this in libpng; png_set_expand_16 should cause 16 bit
-       * calculations to be used throughout.
-       */
-      if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
-         in_sample_depth = 8;
-      else
-         in_sample_depth = in_bd;
-
-      if (sample_depth != 16 || in_sample_depth > 8 ||
-         !dp->pm->calculations_use_input_precision)
-         digitization_error = .5;
-
-      /* Else errors are at 8 bit precision, scale .5 in 8 bits to the 16 bits:
-       */
-      else
-         digitization_error = .5 * 257;
-   }
-
-   for (y=0; y<h; ++y)
-   {
-      png_const_bytep PNG_CONST pRow = store_image_row(ps, pp, 0, y);
-      png_uint_32 x;
-
-      /* The original, standard, row pre-transforms. */
-      png_byte std[STANDARD_ROWMAX];
-
-      transform_row(pp, std, in_ct, in_bd, y);
-
-      /* Go through each original pixel transforming it and comparing with what
-       * libpng did to the same pixel.
-       */
-      for (x=0; x<w; ++x)
-      {
-         image_pixel in_pixel, out_pixel;
-         unsigned int r, g, b, a;
-
-         /* Find out what we think the pixel should be: */
-         image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette);
-
-         in_pixel.red_sBIT = red_sBIT;
-         in_pixel.green_sBIT = green_sBIT;
-         in_pixel.blue_sBIT = blue_sBIT;
-         in_pixel.alpha_sBIT = alpha_sBIT;
-         in_pixel.have_tRNS = have_tRNS;
-
-         /* For error detection, below. */
-         r = in_pixel.red;
-         g = in_pixel.green;
-         b = in_pixel.blue;
-         a = in_pixel.alpha;
-
-         dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
-
-         /* Read the output pixel and compare it to what we got, we don't
-          * use the error field here, so no need to update sBIT.
-          */
-         image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette);
-
-         /* We don't expect changes to the index here even if the bit depth is
-          * changed.
-          */
-         if (in_ct == PNG_COLOR_TYPE_PALETTE &&
-            out_ct == PNG_COLOR_TYPE_PALETTE)
-         {
-            if (in_pixel.palette_index != out_pixel.palette_index)
-               png_error(pp, "unexpected transformed palette index");
-         }
-
-         /* Check the colours for palette images too - in fact the palette could
-          * be separately verified itself in most cases.
-          */
-         if (in_pixel.red != out_pixel.red)
-            transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
-               out_pixel.red, sample_depth, in_pixel.rede,
-               dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
-               digitization_error);
-
-         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
-            in_pixel.green != out_pixel.green)
-            transform_range_check(pp, r, g, b, a, in_pixel.green,
-               in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
-               dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
-               digitization_error);
-
-         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
-            in_pixel.blue != out_pixel.blue)
-            transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
-               out_pixel.blue, sample_depth, in_pixel.bluee,
-               dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
-               digitization_error);
-
-         if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
-            in_pixel.alpha != out_pixel.alpha)
-            transform_range_check(pp, r, g, b, a, in_pixel.alpha,
-               in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
-               dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
-               digitization_error);
-      } /* pixel (x) loop */
-   } /* row (y) loop */
-
-   /* Record that something was actually checked to avoid a false positive. */
-   dp->this.ps->validated = 1;
-}
-
-static void
-transform_end(png_structp pp, png_infop pi)
-{
-   transform_display *dp = voidcast(transform_display*,
-      png_get_progressive_ptr(pp));
-
-   if (!dp->this.speed)
-      transform_image_validate(dp, pp, pi);
-   else
-      dp->this.ps->validated = 1;
-}
-
-/* A single test run. */
-static void
-transform_test(png_modifier *pmIn, PNG_CONST png_uint_32 idIn,
-    PNG_CONST image_transform* transform_listIn, PNG_CONST char * volatile name)
-{
-   transform_display d;
-   context(&pmIn->this, fault);
-
-   transform_display_init(&d, pmIn, idIn, transform_listIn);
-
-   Try
-   {
-      size_t pos = 0;
-      png_structp pp;
-      png_infop pi;
-      char full_name[256];
-
-      /* Make sure the encoding fields are correct and enter the required
-       * modifications.
-       */
-      transform_set_encoding(&d);
-
-      /* Add any modifications required by the transform list. */
-      d.transform_list->ini(d.transform_list, &d);
-
-      /* Add the color space information, if any, to the name. */
-      pos = safecat(full_name, sizeof full_name, pos, name);
-      pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
-
-      /* Get a png_struct for reading the image. */
-      pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
-      standard_palette_init(&d.this);
-
-#     if 0
-         /* Logging (debugging only) */
-         {
-            char buffer[256];
-
-            (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
-               "running test");
-
-            fprintf(stderr, "%s\n", buffer);
-         }
-#     endif
-
-      /* Introduce the correct read function. */
-      if (d.pm->this.progressive)
-      {
-         /* Share the row function with the standard implementation. */
-         png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
-            transform_end);
-
-         /* Now feed data into the reader until we reach the end: */
-         modifier_progressive_read(d.pm, pp, pi);
-      }
-      else
-      {
-         /* modifier_read expects a png_modifier* */
-         png_set_read_fn(pp, d.pm, modifier_read);
-
-         /* Check the header values: */
-         png_read_info(pp, pi);
-
-         /* Process the 'info' requirements. Only one image is generated */
-         transform_info_imp(&d, pp, pi);
-
-         sequential_row(&d.this, pp, pi, -1, 0);
-
-         if (!d.this.speed)
-            transform_image_validate(&d, pp, pi);
-         else
-            d.this.ps->validated = 1;
-      }
-
-      modifier_reset(d.pm);
-   }
-
-   Catch(fault)
-   {
-      modifier_reset((png_modifier*)fault);
-   }
-}
-
-/* The transforms: */
-#define ITSTRUCT(name) image_transform_##name
-#define ITDATA(name) image_transform_data_##name
-#define image_transform_ini image_transform_default_ini
-#define IT(name)\
-static image_transform ITSTRUCT(name) =\
-{\
-   #name,\
-   1, /*enable*/\
-   &PT, /*list*/\
-   0, /*global_use*/\
-   0, /*local_use*/\
-   0, /*next*/\
-   image_transform_ini,\
-   image_transform_png_set_##name##_set,\
-   image_transform_png_set_##name##_mod,\
-   image_transform_png_set_##name##_add\
-}
-#define PT ITSTRUCT(end) /* stores the previous transform */
-
-/* To save code: */
-static void
-image_transform_default_ini(PNG_CONST image_transform *this,
-    transform_display *that)
-{
-   this->next->ini(this->next, that);
-}
-
-static int
-image_transform_default_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(colour_type)
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return 1;
-}
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* png_set_palette_to_rgb */
-static void
-image_transform_png_set_palette_to_rgb_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_palette_to_rgb(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_palette_to_rgb_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
-      image_pixel_convert_PLTE(that);
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_palette_to_rgb_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return colour_type == PNG_COLOR_TYPE_PALETTE;
-}
-
-IT(palette_to_rgb);
-#undef PT
-#define PT ITSTRUCT(palette_to_rgb)
-#endif /* PNG_READ_EXPAND_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* png_set_tRNS_to_alpha */
-static void
-image_transform_png_set_tRNS_to_alpha_set(PNG_CONST image_transform *this,
-   transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_tRNS_to_alpha(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_tRNS_to_alpha_mod(PNG_CONST image_transform *this,
-   image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   /* LIBPNG BUG: this always forces palette images to RGB. */
-   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
-      image_pixel_convert_PLTE(that);
-
-   /* This effectively does an 'expand' only if there is some transparency to
-    * convert to an alpha channel.
-    */
-   if (that->have_tRNS)
-      image_pixel_add_alpha(that, &display->this);
-
-   /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
-   else
-   {
-      if (that->bit_depth < 8)
-         that->bit_depth =8;
-      if (that->sample_depth < 8)
-         that->sample_depth = 8;
-   }
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   /* We don't know yet whether there will be a tRNS chunk, but we know that
-    * this transformation should do nothing if there already is an alpha
-    * channel.
-    */
-   return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
-}
-
-IT(tRNS_to_alpha);
-#undef PT
-#define PT ITSTRUCT(tRNS_to_alpha)
-#endif /* PNG_READ_EXPAND_SUPPORTED */
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-/* png_set_gray_to_rgb */
-static void
-image_transform_png_set_gray_to_rgb_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_gray_to_rgb(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_gray_to_rgb_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   /* NOTE: we can actually pend the tRNS processing at this point because we
-    * can correctly recognize the original pixel value even though we have
-    * mapped the one gray channel to the three RGB ones, but in fact libpng
-    * doesn't do this, so we don't either.
-    */
-   if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
-      image_pixel_add_alpha(that, &display->this);
-
-   /* Simply expand the bit depth and alter the colour type as required. */
-   if (that->colour_type == PNG_COLOR_TYPE_GRAY)
-   {
-      /* RGB images have a bit depth at least equal to '8' */
-      if (that->bit_depth < 8)
-         that->sample_depth = that->bit_depth = 8;
-
-      /* And just changing the colour type works here because the green and blue
-       * channels are being maintained in lock-step with the red/gray:
-       */
-      that->colour_type = PNG_COLOR_TYPE_RGB;
-   }
-
-   else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_gray_to_rgb_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
-}
-
-IT(gray_to_rgb);
-#undef PT
-#define PT ITSTRUCT(gray_to_rgb)
-#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* png_set_expand */
-static void
-image_transform_png_set_expand_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_expand(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_expand_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   /* The general expand case depends on what the colour type is: */
-   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
-      image_pixel_convert_PLTE(that);
-   else if (that->bit_depth < 8) /* grayscale */
-      that->sample_depth = that->bit_depth = 8;
-
-   if (that->have_tRNS)
-      image_pixel_add_alpha(that, &display->this);
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_expand_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
-    * depth is at least 8 already.
-    */
-   return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
-}
-
-IT(expand);
-#undef PT
-#define PT ITSTRUCT(expand)
-#endif /* PNG_READ_EXPAND_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* png_set_expand_gray_1_2_4_to_8
- * LIBPNG BUG: this just does an 'expand'
- */
-static void
-image_transform_png_set_expand_gray_1_2_4_to_8_set(
-    PNG_CONST image_transform *this, transform_display *that, png_structp pp,
-    png_infop pi)
-{
-   png_set_expand_gray_1_2_4_to_8(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_expand_gray_1_2_4_to_8_mod(
-    PNG_CONST image_transform *this, image_pixel *that, png_structp pp,
-    PNG_CONST transform_display *display)
-{
-   image_transform_png_set_expand_mod(this, that, pp, display);
-}
-
-static int
-image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   return image_transform_png_set_expand_add(this, that, colour_type,
-      bit_depth);
-}
-
-IT(expand_gray_1_2_4_to_8);
-#undef PT
-#define PT ITSTRUCT(expand_gray_1_2_4_to_8)
-#endif /* PNG_READ_EXPAND_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* png_set_expand_16 */
-static void
-image_transform_png_set_expand_16_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_expand_16(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_expand_16_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   /* Expect expand_16 to expand everything to 16 bits as a result of also
-    * causing 'expand' to happen.
-    */
-   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
-      image_pixel_convert_PLTE(that);
-
-   if (that->have_tRNS)
-      image_pixel_add_alpha(that, &display->this);
-
-   if (that->bit_depth < 16)
-      that->sample_depth = that->bit_depth = 16;
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_expand_16_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(colour_type)
-
-   this->next = *that;
-   *that = this;
-
-   /* expand_16 does something unless the bit depth is already 16. */
-   return bit_depth < 16;
-}
-
-IT(expand_16);
-#undef PT
-#define PT ITSTRUCT(expand_16)
-#endif /* PNG_READ_EXPAND_16_SUPPORTED */
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED  /* API added in 1.5.4 */
-/* png_set_scale_16 */
-static void
-image_transform_png_set_scale_16_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_scale_16(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_scale_16_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   if (that->bit_depth == 16)
-   {
-      that->sample_depth = that->bit_depth = 8;
-      if (that->red_sBIT > 8) that->red_sBIT = 8;
-      if (that->green_sBIT > 8) that->green_sBIT = 8;
-      if (that->blue_sBIT > 8) that->blue_sBIT = 8;
-      if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
-   }
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_scale_16_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(colour_type)
-
-   this->next = *that;
-   *that = this;
-
-   return bit_depth > 8;
-}
-
-IT(scale_16);
-#undef PT
-#define PT ITSTRUCT(scale_16)
-#endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
-
-#ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
-/* png_set_strip_16 */
-static void
-image_transform_png_set_strip_16_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_strip_16(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_strip_16_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   if (that->bit_depth == 16)
-   {
-      that->sample_depth = that->bit_depth = 8;
-      if (that->red_sBIT > 8) that->red_sBIT = 8;
-      if (that->green_sBIT > 8) that->green_sBIT = 8;
-      if (that->blue_sBIT > 8) that->blue_sBIT = 8;
-      if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
-
-      /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
-       * configuration option is set.  From 1.5.4 the flag is never set and the
-       * 'scale' API (above) must be used.
-       */
-#     ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
-#        if PNG_LIBPNG_VER >= 10504
-#           error PNG_READ_ACCURATE_SCALE should not be set
-#        endif
-
-         /* The strip 16 algorithm drops the low 8 bits rather than calculating
-          * 1/257, so we need to adjust the permitted errors appropriately:
-          * Notice that this is only relevant prior to the addition of the
-          * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
-          */
-         {
-            PNG_CONST double d = (255-128.5)/65535;
-            that->rede += d;
-            that->greene += d;
-            that->bluee += d;
-            that->alphae += d;
-         }
-#     endif
-   }
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_strip_16_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(colour_type)
-
-   this->next = *that;
-   *that = this;
-
-   return bit_depth > 8;
-}
-
-IT(strip_16);
-#undef PT
-#define PT ITSTRUCT(strip_16)
-#endif /* PNG_READ_16_TO_8_SUPPORTED */
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-/* png_set_strip_alpha */
-static void
-image_transform_png_set_strip_alpha_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_strip_alpha(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_strip_alpha_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      that->colour_type = PNG_COLOR_TYPE_GRAY;
-   else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
-      that->colour_type = PNG_COLOR_TYPE_RGB;
-
-   that->have_tRNS = 0;
-   that->alphaf = 1;
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_strip_alpha_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
-}
-
-IT(strip_alpha);
-#undef PT
-#define PT ITSTRUCT(strip_alpha)
-#endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
- * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
- *    png_fixed_point green)
- * png_get_rgb_to_gray_status
- *
- * The 'default' test here uses values known to be used inside libpng:
- *
- *   red:    6968
- *   green: 23434
- *   blue:   2366
- *
- * These values are being retained for compatibility, along with the somewhat
- * broken truncation calculation in the fast-and-inaccurate code path.  Older
- * versions of libpng will fail the accuracy tests below because they use the
- * truncation algorithm everywhere.
- */
-#define data ITDATA(rgb_to_gray)
-static struct
-{
-   double gamma;      /* File gamma to use in processing */
-
-   /* The following are the parameters for png_set_rgb_to_gray: */
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-      double red_to_set;
-      double green_to_set;
-#  else
-      png_fixed_point red_to_set;
-      png_fixed_point green_to_set;
-#  endif
-
-   /* The actual coefficients: */
-   double red_coefficient;
-   double green_coefficient;
-   double blue_coefficient;
-
-   /* Set if the coeefficients have been overridden. */
-   int coefficients_overridden;
-} data;
-
-#undef image_transform_ini
-#define image_transform_ini image_transform_png_set_rgb_to_gray_ini
-static void
-image_transform_png_set_rgb_to_gray_ini(PNG_CONST image_transform *this,
-    transform_display *that)
-{
-   png_modifier *pm = that->pm;
-   PNG_CONST color_encoding *e = pm->current_encoding;
-
-   UNUSED(this)
-
-   /* Since we check the encoding this flag must be set: */
-   pm->test_uses_encoding = 1;
-
-   /* If 'e' is not NULL chromaticity information is present and either a cHRM
-    * or an sRGB chunk will be inserted.
-    */
-   if (e != 0)
-   {
-      /* Coefficients come from the encoding, but may need to be normalized to a
-       * white point Y of 1.0
-       */
-      PNG_CONST double whiteY = e->red.Y + e->green.Y + e->blue.Y;
-
-      data.red_coefficient = e->red.Y;
-      data.green_coefficient = e->green.Y;
-      data.blue_coefficient = e->blue.Y;
-
-      if (whiteY != 1)
-      {
-         data.red_coefficient /= whiteY;
-         data.green_coefficient /= whiteY;
-         data.blue_coefficient /= whiteY;
-      }
-   }
-
-   else
-   {
-      /* The default (built in) coeffcients, as above: */
-      data.red_coefficient = 6968 / 32768.;
-      data.green_coefficient = 23434 / 32768.;
-      data.blue_coefficient = 2366 / 32768.;
-   }
-
-   data.gamma = pm->current_gamma;
-
-   /* If not set then the calculations assume linear encoding (implicitly): */
-   if (data.gamma == 0)
-      data.gamma = 1;
-
-   /* The arguments to png_set_rgb_to_gray can override the coefficients implied
-    * by the color space encoding.  If doing exhaustive checks do the override
-    * in each case, otherwise do it randomly.
-    */
-   if (pm->test_exhaustive)
-   {
-      /* First time in coefficients_overridden is 0, the following sets it to 1,
-       * so repeat if it is set.  If a test fails this may mean we subsequently
-       * skip a non-override test, ignore that.
-       */
-      data.coefficients_overridden = !data.coefficients_overridden;
-      pm->repeat = data.coefficients_overridden != 0;
-   }
-
-   else
-      data.coefficients_overridden = random_choice();
-
-   if (data.coefficients_overridden)
-   {
-      /* These values override the color encoding defaults, simply use random
-       * numbers.
-       */
-      png_uint_32 ru;
-      double total;
-
-      RANDOMIZE(ru);
-      data.green_coefficient = total = (ru & 0xffff) / 65535.;
-      ru >>= 16;
-      data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
-      total += data.red_coefficient;
-      data.blue_coefficient = 1 - total;
-
-#     ifdef PNG_FLOATING_POINT_SUPPORTED
-         data.red_to_set = data.red_coefficient;
-         data.green_to_set = data.green_coefficient;
-#     else
-         data.red_to_set = fix(data.red_coefficient);
-         data.green_to_set = fix(data.green_coefficient);
-#     endif
-
-      /* The following just changes the error messages: */
-      pm->encoding_ignored = 1;
-   }
-
-   else
-   {
-      data.red_to_set = -1;
-      data.green_to_set = -1;
-   }
-
-   /* Adjust the error limit in the png_modifier because of the larger errors
-    * produced in the digitization during the gamma handling.
-    */
-   if (data.gamma != 1) /* Use gamma tables */
-   {
-      if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
-      {
-         /* The 16 bit case ends up producing a maximum error of about
-          * +/-5 in 65535, allow for +/-8 with the given gamma.
-          */
-         that->pm->limit += pow(8./65535, data.gamma);
-      }
-
-      else
-      {
-         /* Rounding to 8 bits in the linear space causes massive errors which
-          * will trigger the error check in transform_range_check.  Fix that
-          * here by taking the gamma encoding into account.
-          */
-         that->pm->limit += pow(1./255, data.gamma);
-      }
-   }
-
-   else
-   {
-      /* With no gamma correction a large error comes from the truncation of the
-       * calculation in the 8 bit case, allow for that here.
-       */
-      if (that->this.bit_depth != 16)
-         that->pm->limit += 4E-3;
-   }
-}
-
-static void
-image_transform_png_set_rgb_to_gray_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   PNG_CONST int error_action = 1; /* no error, no defines in png.h */
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-      png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
-#  else
-      png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
-         data.green_to_set);
-#  endif
-
-#  ifdef PNG_READ_cHRM_SUPPORTED
-      if (that->pm->current_encoding != 0)
-      {
-         /* We have an encoding so a cHRM chunk may have been set; if so then
-          * check that the libpng APIs give the correct (X,Y,Z) values within
-          * some margin of error for the round trip through the chromaticity
-          * form.
-          */
-#        ifdef PNG_FLOATING_POINT_SUPPORTED
-#           define API_function png_get_cHRM_XYZ
-#           define API_form "FP"
-#           define API_type double
-#           define API_cvt(x) (x)
-#        else
-#           define API_function png_get_cHRM_XYZ_fixed
-#           define API_form "fixed"
-#           define API_type png_fixed_point
-#           define API_cvt(x) ((double)(x)/PNG_FP_1)
-#        endif
-
-         API_type rX, gX, bX;
-         API_type rY, gY, bY;
-         API_type rZ, gZ, bZ;
-
-         if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
-               & PNG_INFO_cHRM) != 0)
-         {
-            double maxe;
-            PNG_CONST char *el;
-            color_encoding e, o;
-
-            /* Expect libpng to return a normalized result, but the original
-             * color space encoding may not be normalized.
-             */
-            modifier_current_encoding(that->pm, &o);
-            normalize_color_encoding(&o);
-
-            /* Sanity check the pngvalid code - the coefficients should match
-             * the normalized Y values of the encoding unless they were
-             * overridden.
-             */
-            if (data.red_to_set == -1 && data.green_to_set == -1 &&
-               (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
-               fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
-               fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
-               png_error(pp, "internal pngvalid cHRM coefficient error");
-
-            /* Generate a colour space encoding. */
-            e.gamma = o.gamma; /* not used */
-            e.red.X = API_cvt(rX);
-            e.red.Y = API_cvt(rY);
-            e.red.Z = API_cvt(rZ);
-            e.green.X = API_cvt(gX);
-            e.green.Y = API_cvt(gY);
-            e.green.Z = API_cvt(gZ);
-            e.blue.X = API_cvt(bX);
-            e.blue.Y = API_cvt(bY);
-            e.blue.Z = API_cvt(bZ);
-
-            /* This should match the original one from the png_modifier, within
-             * the range permitted by the libpng fixed point representation.
-             */
-            maxe = 0;
-            el = "-"; /* Set to element name with error */
-
-#           define CHECK(col,x)\
-            {\
-               double err = fabs(o.col.x - e.col.x);\
-               if (err > maxe)\
-               {\
-                  maxe = err;\
-                  el = #col "(" #x ")";\
-               }\
-            }
-
-            CHECK(red,X)
-            CHECK(red,Y)
-            CHECK(red,Z)
-            CHECK(green,X)
-            CHECK(green,Y)
-            CHECK(green,Z)
-            CHECK(blue,X)
-            CHECK(blue,Y)
-            CHECK(blue,Z)
-
-            /* Here in both fixed and floating cases to check the values read
-             * from the cHRm chunk.  PNG uses fixed point in the cHRM chunk, so
-             * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
-             */
-            if (maxe >= 1E-5)
-            {
-               size_t pos = 0;
-               char buffer[256];
-
-               pos = safecat(buffer, sizeof buffer, pos, API_form);
-               pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
-               pos = safecat(buffer, sizeof buffer, pos, el);
-               pos = safecat(buffer, sizeof buffer, pos, " error: ");
-               pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
-               pos = safecat(buffer, sizeof buffer, pos, " ");
-               /* Print the color space without the gamma value: */
-               pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
-               pos = safecat(buffer, sizeof buffer, pos, " -> ");
-               pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
-
-               png_error(pp, buffer);
-            }
-         }
-      }
-#  endif /* READ_cHRM */
-
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_rgb_to_gray_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
-   {
-      double gray, err;
-
-      if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
-         image_pixel_convert_PLTE(that);
-
-      /* Image now has RGB channels... */
-      {
-         PNG_CONST png_modifier *pm = display->pm;
-         PNG_CONST unsigned int sample_depth = that->sample_depth;
-         int isgray;
-         double r, g, b;
-         double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
-
-         /* Do this using interval arithmetic, otherwise it is too difficult to
-          * handle the errors correctly.
-          *
-          * To handle the gamma correction work out the upper and lower bounds
-          * of the digitized value.  Assume rounding here - normally the values
-          * will be identical after this operation if there is only one
-          * transform, feel free to delete the png_error checks on this below in
-          * the future (this is just me trying to ensure it works!)
-          */
-         r = rlo = rhi = that->redf;
-         rlo -= that->rede;
-         rlo = digitize(pm, rlo, sample_depth, 1/*round*/);
-         rhi += that->rede;
-         rhi = digitize(pm, rhi, sample_depth, 1/*round*/);
-
-         g = glo = ghi = that->greenf;
-         glo -= that->greene;
-         glo = digitize(pm, glo, sample_depth, 1/*round*/);
-         ghi += that->greene;
-         ghi = digitize(pm, ghi, sample_depth, 1/*round*/);
-
-         b = blo = bhi = that->bluef;
-         blo -= that->bluee;
-         blo = digitize(pm, blo, sample_depth, 1/*round*/);
-         bhi += that->greene;
-         bhi = digitize(pm, bhi, sample_depth, 1/*round*/);
-
-         isgray = r==g && g==b;
-
-         if (data.gamma != 1)
-         {
-            PNG_CONST double power = 1/data.gamma;
-            PNG_CONST double abse = abserr(pm, sample_depth, sample_depth);
-
-            /* 'abse' is the absolute error permitted in linear calculations. It
-             * is used here to capture the error permitted in the handling
-             * (undoing) of the gamma encoding.  Once again digitization occurs
-             * to handle the upper and lower bounds of the values.  This is
-             * where the real errors are introduced.
-             */
-            r = pow(r, power);
-            rlo = digitize(pm, pow(rlo, power)-abse, sample_depth, 1);
-            rhi = digitize(pm, pow(rhi, power)+abse, sample_depth, 1);
-
-            g = pow(g, power);
-            glo = digitize(pm, pow(glo, power)-abse, sample_depth, 1);
-            ghi = digitize(pm, pow(ghi, power)+abse, sample_depth, 1);
-
-            b = pow(b, power);
-            blo = digitize(pm, pow(blo, power)-abse, sample_depth, 1);
-            bhi = digitize(pm, pow(bhi, power)+abse, sample_depth, 1);
-         }
-
-         /* Now calculate the actual gray values.  Although the error in the
-          * coefficients depends on whether they were specified on the command
-          * line (in which case truncation to 15 bits happened) or not (rounding
-          * was used) the maxium error in an individual coefficient is always
-          * 1/32768, because even in the rounding case the requirement that
-          * coefficients add up to 32768 can cause a larger rounding error.
-          *
-          * The only time when rounding doesn't occur in 1.5.5 and later is when
-          * the non-gamma code path is used for less than 16 bit data.
-          */
-         gray = r * data.red_coefficient + g * data.green_coefficient +
-            b * data.blue_coefficient;
-
-         {
-            PNG_CONST int do_round = data.gamma != 1 || sample_depth == 16;
-            PNG_CONST double ce = 1. / 32768;
-
-            graylo = digitize(pm, rlo * (data.red_coefficient-ce) +
-               glo * (data.green_coefficient-ce) +
-               blo * (data.blue_coefficient-ce), sample_depth, do_round);
-            if (graylo <= 0)
-               graylo = 0;
-
-            grayhi = digitize(pm, rhi * (data.red_coefficient+ce) +
-               ghi * (data.green_coefficient+ce) +
-               bhi * (data.blue_coefficient+ce), sample_depth, do_round);
-            if (grayhi >= 1)
-               grayhi = 1;
-         }
-
-         /* And invert the gamma. */
-         if (data.gamma != 1)
-         {
-            PNG_CONST double power = data.gamma;
-
-            gray = pow(gray, power);
-            graylo = digitize(pm, pow(graylo, power), sample_depth, 1);
-            grayhi = digitize(pm, pow(grayhi, power), sample_depth, 1);
-         }
-
-         /* Now the error can be calculated.
-          *
-          * If r==g==b because there is no overall gamma correction libpng
-          * currently preserves the original value.
-          */
-         if (isgray)
-            err = (that->rede + that->greene + that->bluee)/3;
-
-         else
-         {
-            err = fabs(grayhi-gray);
-            if (fabs(gray - graylo) > err)
-               err = fabs(graylo-gray);
-
-            /* Check that this worked: */
-            if (err > display->pm->limit)
-            {
-               size_t pos = 0;
-               char buffer[128];
-
-               pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
-               pos = safecatd(buffer, sizeof buffer, pos, err, 6);
-               pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
-               pos = safecatd(buffer, sizeof buffer, pos,
-                  display->pm->limit, 6);
-               png_error(pp, buffer);
-            }
-         }
-      }
-
-      that->bluef = that->greenf = that->redf = gray;
-      that->bluee = that->greene = that->rede = err;
-
-      /* The sBIT is the minium of the three colour channel sBITs. */
-      if (that->red_sBIT > that->green_sBIT)
-         that->red_sBIT = that->green_sBIT;
-      if (that->red_sBIT > that->blue_sBIT)
-         that->red_sBIT = that->blue_sBIT;
-      that->blue_sBIT = that->green_sBIT = that->red_sBIT;
-
-      /* And remove the colour bit in the type: */
-      if (that->colour_type == PNG_COLOR_TYPE_RGB)
-         that->colour_type = PNG_COLOR_TYPE_GRAY;
-      else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
-         that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
-   }
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_rgb_to_gray_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
-}
-
-#undef data
-IT(rgb_to_gray);
-#undef PT
-#define PT ITSTRUCT(rgb_to_gray)
-#undef image_transform_ini
-#define image_transform_ini image_transform_default_ini
-#endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-/* png_set_background(png_structp, png_const_color_16p background_color,
- *    int background_gamma_code, int need_expand, double background_gamma)
- * png_set_background_fixed(png_structp, png_const_color_16p background_color,
- *    int background_gamma_code, int need_expand,
- *    png_fixed_point background_gamma)
- *
- * As with rgb_to_gray this ignores the gamma (at present.)
-*/
-#define data ITDATA(background)
-static image_pixel data;
-
-static void
-image_transform_png_set_background_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_byte colour_type, bit_depth;
-   png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
-   png_color_16 back;
-
-   /* We need a background colour, because we don't know exactly what transforms
-    * have been set we have to supply the colour in the original file format and
-    * so we need to know what that is!  The background colour is stored in the
-    * transform_display.
-    */
-   RANDOMIZE(random_bytes);
-
-   /* Read the random value, for colour type 3 the background colour is actually
-    * expressed as a 24bit rgb, not an index.
-    */
-   colour_type = that->this.colour_type;
-   if (colour_type == 3)
-   {
-      colour_type = PNG_COLOR_TYPE_RGB;
-      bit_depth = 8;
-   }
-
-   else
-      bit_depth = that->this.bit_depth;
-
-   image_pixel_init(&data, random_bytes, colour_type,
-      bit_depth, 0/*x*/, 0/*unused: palette*/);
-
-   /* Extract the background colour from this image_pixel, but make sure the
-    * unused fields of 'back' are garbage.
-    */
-   RANDOMIZE(back);
-
-   if (colour_type & PNG_COLOR_MASK_COLOR)
-   {
-      back.red = (png_uint_16)data.red;
-      back.green = (png_uint_16)data.green;
-      back.blue = (png_uint_16)data.blue;
-   }
-
-   else
-      back.gray = (png_uint_16)data.red;
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-      png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, 1/*need expand*/,
-         0);
-#  else
-      png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE,
-         1/*need expand*/, 0);
-#  endif
-
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_background_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   /* Check for tRNS first: */
-   if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
-      image_pixel_add_alpha(that, &display->this);
-
-   /* This is only necessary if the alpha value is less than 1. */
-   if (that->alphaf < 1)
-   {
-      /* Now we do the background calculation without any gamma correction. */
-      if (that->alphaf <= 0)
-      {
-         that->redf = data.redf;
-         that->greenf = data.greenf;
-         that->bluef = data.bluef;
-
-         that->rede = data.rede;
-         that->greene = data.greene;
-         that->bluee = data.bluee;
-
-         that->red_sBIT= data.red_sBIT;
-         that->green_sBIT= data.green_sBIT;
-         that->blue_sBIT= data.blue_sBIT;
-      }
-
-      else /* 0 < alpha < 1 */
-      {
-         double alf = 1 - that->alphaf;
-
-         that->redf = that->redf * that->alphaf + data.redf * alf;
-         that->rede = that->rede * that->alphaf + data.rede * alf +
-            DBL_EPSILON;
-         that->greenf = that->greenf * that->alphaf + data.greenf * alf;
-         that->greene = that->greene * that->alphaf + data.greene * alf +
-            DBL_EPSILON;
-         that->bluef = that->bluef * that->alphaf + data.bluef * alf;
-         that->bluee = that->bluee * that->alphaf + data.bluee * alf +
-            DBL_EPSILON;
-      }
-
-      /* Remove the alpha type and set the alpha (not in that order.) */
-      that->alphaf = 1;
-      that->alphae = 0;
-
-      if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
-         that->colour_type = PNG_COLOR_TYPE_RGB;
-      else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-         that->colour_type = PNG_COLOR_TYPE_GRAY;
-      /* PNG_COLOR_TYPE_PALETTE is not changed */
-   }
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-#define image_transform_png_set_background_add image_transform_default_add
-
-#undef data
-IT(background);
-#undef PT
-#define PT ITSTRUCT(background)
-#endif /* PNG_READ_BACKGROUND_SUPPORTED */
-
-/* This may just be 'end' if all the transforms are disabled! */
-static image_transform *PNG_CONST image_transform_first = &PT;
-
-static void
-transform_enable(PNG_CONST char *name)
-{
-   /* Everything starts out enabled, so if we see an 'enable' disabled
-    * everything else the first time round.
-    */
-   static int all_disabled = 0;
-   int found_it = 0;
-   image_transform *list = image_transform_first;
-
-   while (list != &image_transform_end)
-   {
-      if (strcmp(list->name, name) == 0)
-      {
-         list->enable = 1;
-         found_it = 1;
-      }
-      else if (!all_disabled)
-         list->enable = 0;
-
-      list = list->list;
-   }
-
-   all_disabled = 1;
-
-   if (!found_it)
-   {
-      fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
-         name);
-      exit(1);
-   }
-}
-
-static void
-transform_disable(PNG_CONST char *name)
-{
-   image_transform *list = image_transform_first;
-
-   while (list != &image_transform_end)
-   {
-      if (strcmp(list->name, name) == 0)
-      {
-         list->enable = 0;
-         return;
-      }
-
-      list = list->list;
-   }
-
-   fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
-      name);
-   exit(1);
-}
-
-static void
-image_transform_reset_count(void)
-{
-   image_transform *next = image_transform_first;
-   int count = 0;
-
-   while (next != &image_transform_end)
-   {
-      next->local_use = 0;
-      next->next = 0;
-      next = next->list;
-      ++count;
-   }
-
-   /* This can only happen if we every have more than 32 transforms (excluding
-    * the end) in the list.
-    */
-   if (count > 32) abort();
-}
-
-static int
-image_transform_test_counter(png_uint_32 counter, unsigned int max)
-{
-   /* Test the list to see if there is any point contining, given a current
-    * counter and a 'max' value.
-    */
-   image_transform *next = image_transform_first;
-
-   while (next != &image_transform_end)
-   {
-      /* For max 0 or 1 continue until the counter overflows: */
-      counter >>= 1;
-
-      /* Continue if any entry hasn't reacked the max. */
-      if (max > 1 && next->local_use < max)
-         return 1;
-      next = next->list;
-   }
-
-   return max <= 1 && counter == 0;
-}
-
-static png_uint_32
-image_transform_add(PNG_CONST image_transform **this, unsigned int max,
-   png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
-   png_byte colour_type, png_byte bit_depth)
-{
-   for (;;) /* until we manage to add something */
-   {
-      png_uint_32 mask;
-      image_transform *list;
-
-      /* Find the next counter value, if the counter is zero this is the start
-       * of the list.  This routine always returns the current counter (not the
-       * next) so it returns 0 at the end and expects 0 at the beginning.
-       */
-      if (counter == 0) /* first time */
-      {
-         image_transform_reset_count();
-         if (max <= 1)
-            counter = 1;
-         else
-            counter = random_32();
-      }
-      else /* advance the counter */
-      {
-         switch (max)
-         {
-            case 0:  ++counter; break;
-            case 1:  counter <<= 1; break;
-            default: counter = random_32(); break;
-         }
-      }
-
-      /* Now add all these items, if possible */
-      *this = &image_transform_end;
-      list = image_transform_first;
-      mask = 1;
-
-      /* Go through the whole list adding anything that the counter selects: */
-      while (list != &image_transform_end)
-      {
-         if ((counter & mask) != 0 && list->enable &&
-             (max == 0 || list->local_use < max))
-         {
-            /* Candidate to add: */
-            if (list->add(list, this, colour_type, bit_depth) || max == 0)
-            {
-               /* Added, so add to the name too. */
-               *pos = safecat(name, sizeof_name, *pos, " +");
-               *pos = safecat(name, sizeof_name, *pos, list->name);
-            }
-
-            else
-            {
-               /* Not useful and max>0, so remove it from *this: */
-               *this = list->next;
-               list->next = 0;
-
-               /* And, since we know it isn't useful, stop it being added again
-                * in this run:
-                */
-               list->local_use = max;
-            }
-         }
-
-         mask <<= 1;
-         list = list->list;
-      }
-
-      /* Now if anything was added we have something to do. */
-      if (*this != &image_transform_end)
-         return counter;
-
-      /* Nothing added, but was there anything in there to add? */
-      if (!image_transform_test_counter(counter, max))
-         return 0;
-   }
-}
-
-#ifdef THIS_IS_THE_PROFORMA
-static void
-image_transform_png_set_@_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_@(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_@_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_@_add(image_transform *this,
-    PNG_CONST image_transform **that, char *name, size_t sizeof_name,
-    size_t *pos, png_byte colour_type, png_byte bit_depth)
-{
-   this->next = *that;
-   *that = this;
-
-   *pos = safecat(name, sizeof_name, *pos, " +@");
-
-   return 1;
-}
-
-IT(@);
-#endif
-
-/* png_set_quantize(png_structp, png_colorp palette, int num_palette,
- *    int maximum_colors, png_const_uint_16p histogram, int full_quantize)
- *
- * Very difficult to validate this!
- */
-/*NOTE: TBD NYI */
-
-/* The data layout transforms are handled by swapping our own channel data,
- * necessarily these need to happen at the end of the transform list because the
- * semantic of the channels changes after these are executed.  Some of these,
- * like set_shift and set_packing, can't be done at present because they change
- * the layout of the data at the sub-sample level so sample() won't get the
- * right answer.
- */
-/* png_set_invert_alpha */
-/*NOTE: TBD NYI */
-
-/* png_set_bgr */
-/*NOTE: TBD NYI */
-
-/* png_set_swap_alpha */
-/*NOTE: TBD NYI */
-
-/* png_set_swap */
-/*NOTE: TBD NYI */
-
-/* png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags)); */
-/*NOTE: TBD NYI */
-
-/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
-/*NOTE: TBD NYI */
-
-/* png_set_packing */
-/*NOTE: TBD NYI */
-
-/* png_set_packswap */
-/*NOTE: TBD NYI */
-
-/* png_set_invert_mono */
-/*NOTE: TBD NYI */
-
-/* png_set_shift(png_structp, png_const_color_8p true_bits) */
-/*NOTE: TBD NYI */
-
-static void
-perform_transform_test(png_modifier *pm)
-{
-   png_byte colour_type = 0;
-   png_byte bit_depth = 0;
-   int palette_number = 0;
-
-   while (next_format(&colour_type, &bit_depth, &palette_number))
-   {
-      png_uint_32 counter = 0;
-      size_t base_pos;
-      char name[64];
-
-      base_pos = safecat(name, sizeof name, 0, "transform:");
-
-      for (;;)
-      {
-         size_t pos = base_pos;
-         PNG_CONST image_transform *list = 0;
-
-         /* 'max' is currently hardwired to '1'; this should be settable on the
-          * command line.
-          */
-         counter = image_transform_add(&list, 1/*max*/, counter,
-            name, sizeof name, &pos, colour_type, bit_depth);
-
-         if (counter == 0)
-            break;
-
-         /* The command line can change this to checking interlaced images. */
-         do
-         {
-            pm->repeat = 0;
-            transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
-               pm->interlace_type, 0, 0, 0), list, name);
-
-            if (fail(pm))
-               return;
-         }
-         while (pm->repeat);
-      }
-   }
-}
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-/********************************* GAMMA TESTS ********************************/
-#ifdef PNG_READ_GAMMA_SUPPORTED
-/* Reader callbacks and implementations, where they differ from the standard
- * ones.
- */
-typedef struct gamma_display
-{
-   standard_display this;
-
-   /* Parameters */
-   png_modifier*    pm;
-   double           file_gamma;
-   double           screen_gamma;
-   double           background_gamma;
-   png_byte         sbit;
-   int              threshold_test;
-   int              use_input_precision;
-   int              scale16;
-   int              expand16;
-   int              do_background;
-   png_color_16     background_color;
-
-   /* Local variables */
-   double       maxerrout;
-   double       maxerrpc;
-   double       maxerrabs;
-} gamma_display;
-
-#define ALPHA_MODE_OFFSET 4
-
-static void
-gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
-    double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
-    int use_input_precision, int scale16, int expand16,
-    int do_background, PNG_CONST png_color_16 *pointer_to_the_background_color,
-    double background_gamma)
-{
-   /* Standard fields */
-   standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
-      pm->use_update_info);
-
-   /* Parameter fields */
-   dp->pm = pm;
-   dp->file_gamma = file_gamma;
-   dp->screen_gamma = screen_gamma;
-   dp->background_gamma = background_gamma;
-   dp->sbit = sbit;
-   dp->threshold_test = threshold_test;
-   dp->use_input_precision = use_input_precision;
-   dp->scale16 = scale16;
-   dp->expand16 = expand16;
-   dp->do_background = do_background;
-   if (do_background && pointer_to_the_background_color != 0)
-      dp->background_color = *pointer_to_the_background_color;
-   else
-      memset(&dp->background_color, 0, sizeof dp->background_color);
-
-   /* Local variable fields */
-   dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
-}
-
-static void
-gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
-{
-   /* Reuse the standard stuff as appropriate. */
-   standard_info_part1(&dp->this, pp, pi);
-
-   /* If requested strip 16 to 8 bits - this is handled automagically below
-    * because the output bit depth is read from the library.  Note that there
-    * are interactions with sBIT but, internally, libpng makes sbit at most
-    * PNG_MAX_GAMMA_8 when doing the following.
-    */
-   if (dp->scale16)
-#     ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-         png_set_scale_16(pp);
-#     else
-         /* The following works both in 1.5.4 and earlier versions: */
-#        ifdef PNG_READ_16_TO_8_SUPPORTED
-            png_set_strip_16(pp);
-#        else
-            png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
-#        endif
-#     endif
-
-   if (dp->expand16)
-#     ifdef PNG_READ_EXPAND_16_SUPPORTED
-         png_set_expand_16(pp);
-#     else
-         png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
-#     endif
-
-   if (dp->do_background >= ALPHA_MODE_OFFSET)
-   {
-#     ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-      {
-         /* This tests the alpha mode handling, if supported. */
-         int mode = dp->do_background - ALPHA_MODE_OFFSET;
-
-         /* The gamma value is the output gamma, and is in the standard,
-          * non-inverted, represenation.  It provides a default for the PNG file
-          * gamma, but since the file has a gAMA chunk this does not matter.
-          */
-         PNG_CONST double sg = dp->screen_gamma;
-#        ifndef PNG_FLOATING_POINT_SUPPORTED
-            PNG_CONST png_fixed_point g = fix(sg);
-#        endif
-
-#        ifdef PNG_FLOATING_POINT_SUPPORTED
-            png_set_alpha_mode(pp, mode, sg);
-#        else
-            png_set_alpha_mode_fixed(pp, mode, g);
-#        endif
-
-         /* However, for the standard Porter-Duff algorithm the output defaults
-          * to be linear, so if the test requires non-linear output it must be
-          * corrected here.
-          */
-         if (mode == PNG_ALPHA_STANDARD && sg != 1)
-         {
-#           ifdef PNG_FLOATING_POINT_SUPPORTED
-               png_set_gamma(pp, sg, dp->file_gamma);
-#           else
-               png_fixed_point f = fix(dp->file_gamma);
-               png_set_gamma_fixed(pp, g, f);
-#           endif
-         }
-      }
-#     else
-         png_error(pp, "alpha mode handling not supported");
-#     endif
-   }
-
-   else
-   {
-      /* Set up gamma processing. */
-#     ifdef PNG_FLOATING_POINT_SUPPORTED
-         png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
-#     else
-      {
-         png_fixed_point s = fix(dp->screen_gamma);
-         png_fixed_point f = fix(dp->file_gamma);
-         png_set_gamma_fixed(pp, s, f);
-      }
-#     endif
-
-      if (dp->do_background)
-      {
-#     ifdef PNG_READ_BACKGROUND_SUPPORTED
-         /* NOTE: this assumes the caller provided the correct background gamma!
-          */
-         PNG_CONST double bg = dp->background_gamma;
-#        ifndef PNG_FLOATING_POINT_SUPPORTED
-            PNG_CONST png_fixed_point g = fix(bg);
-#        endif
-
-#        ifdef PNG_FLOATING_POINT_SUPPORTED
-            png_set_background(pp, &dp->background_color, dp->do_background,
-               0/*need_expand*/, bg);
-#        else
-            png_set_background_fixed(pp, &dp->background_color,
-               dp->do_background, 0/*need_expand*/, g);
-#        endif
-#     else
-         png_error(pp, "png_set_background not supported");
-#     endif
-      }
-   }
-
-   {
-      int i = dp->this.use_update_info;
-      /* Always do one call, even if use_update_info is 0. */
-      do
-         png_read_update_info(pp, pi);
-      while (--i > 0);
-   }
-
-   /* Now we may get a different cbRow: */
-   standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
-}
-
-static void
-gamma_info(png_structp pp, png_infop pi)
-{
-   gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
-      pi);
-}
-
-/* Validate a single component value - the routine gets the input and output
- * sample values as unscaled PNG component values along with a cache of all the
- * information required to validate the values.
- */
-typedef struct validate_info
-{
-   png_structp  pp;
-   gamma_display *dp;
-   png_byte sbit;
-   int use_input_precision;
-   int do_background;
-   int scale16;
-   unsigned int sbit_max;
-   unsigned int isbit_shift;
-   unsigned int outmax;
-
-   double gamma_correction; /* Overall correction required. */
-   double file_inverse;     /* Inverse of file gamma. */
-   double screen_gamma;
-   double screen_inverse;   /* Inverse of screen gamma. */
-
-   double background_red;   /* Linear background value, red or gray. */
-   double background_green;
-   double background_blue;
-
-   double maxabs;
-   double maxpc;
-   double maxcalc;
-   double maxout;
-   double maxout_total;     /* Total including quantization error */
-   double outlog;
-   int    outquant;
-}
-validate_info;
-
-static void
-init_validate_info(validate_info *vi, gamma_display *dp, png_struct *pp,
-    int in_depth, int out_depth)
-{
-   PNG_CONST unsigned int outmax = (1U<<out_depth)-1;
-
-   vi->pp = pp;
-   vi->dp = dp;
-
-   if (dp->sbit > 0 && dp->sbit < in_depth)
-   {
-      vi->sbit = dp->sbit;
-      vi->isbit_shift = in_depth - dp->sbit;
-   }
-
-   else
-   {
-      vi->sbit = (png_byte)in_depth;
-      vi->isbit_shift = 0;
-   }
-
-   vi->sbit_max = (1U << vi->sbit)-1;
-
-   /* This mimics the libpng threshold test, '0' is used to prevent gamma
-    * correction in the validation test.
-    */
-   vi->screen_gamma = dp->screen_gamma;
-   if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
-      vi->screen_gamma = vi->screen_inverse = 0;
-   else
-      vi->screen_inverse = 1/vi->screen_gamma;
-
-   vi->use_input_precision = dp->use_input_precision;
-   vi->outmax = outmax;
-   vi->maxabs = abserr(dp->pm, in_depth, out_depth);
-   vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
-   vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
-   vi->maxout = outerr(dp->pm, in_depth, out_depth);
-   vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
-   vi->maxout_total = vi->maxout + vi->outquant * .5;
-   vi->outlog = outlog(dp->pm, in_depth, out_depth);
-
-   if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
-      (dp->this.colour_type == 3 && dp->this.is_transparent))
-   {
-      vi->do_background = dp->do_background;
-
-      if (vi->do_background != 0)
-      {
-         PNG_CONST double bg_inverse = 1/dp->background_gamma;
-         double r, g, b;
-
-         /* Caller must at least put the gray value into the red channel */
-         r = dp->background_color.red; r /= outmax;
-         g = dp->background_color.green; g /= outmax;
-         b = dp->background_color.blue; b /= outmax;
-
-#     if 0
-         /* libpng doesn't do this optimization, if we do pngvalid will fail.
-          */
-         if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
-#     endif
-         {
-            r = pow(r, bg_inverse);
-            g = pow(g, bg_inverse);
-            b = pow(b, bg_inverse);
-         }
-
-         vi->background_red = r;
-         vi->background_green = g;
-         vi->background_blue = b;
-      }
-   }
-   else
-      vi->do_background = 0;
-
-   if (vi->do_background == 0)
-      vi->background_red = vi->background_green = vi->background_blue = 0;
-
-   vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
-   if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
-      vi->gamma_correction = 0;
-
-   vi->file_inverse = 1/dp->file_gamma;
-   if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
-      vi->file_inverse = 0;
-
-   vi->scale16 = dp->scale16;
-}
-
-/* This function handles composition of a single non-alpha component.  The
- * argument is the input sample value, in the range 0..1, and the alpha value.
- * The result is the composed, linear, input sample.  If alpha is less than zero
- * this is the alpha component and the function should not be called!
- */
-static double
-gamma_component_compose(int do_background, double input_sample, double alpha,
-   double background, int *compose)
-{
-   switch (do_background)
-   {
-      case PNG_BACKGROUND_GAMMA_SCREEN:
-      case PNG_BACKGROUND_GAMMA_FILE:
-      case PNG_BACKGROUND_GAMMA_UNIQUE:
-         /* Standard PNG background processing. */
-         if (alpha < 1)
-         {
-            if (alpha > 0)
-            {
-               input_sample = input_sample * alpha + background * (1-alpha);
-               if (compose != NULL)
-                  *compose = 1;
-            }
-
-            else
-               input_sample = background;
-         }
-         break;
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-      case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
-      case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
-         /* The components are premultiplied in either case and the output is
-          * gamma encoded (to get standard Porter-Duff we expect the output
-          * gamma to be set to 1.0!)
-          */
-      case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
-         /* The optimization is that the partial-alpha entries are linear
-          * while the opaque pixels are gamma encoded, but this only affects the
-          * output encoding.
-          */
-         if (alpha < 1)
-         {
-            if (alpha > 0)
-            {
-               input_sample *= alpha;
-               if (compose != NULL)
-                  *compose = 1;
-            }
-
-            else
-               input_sample = 0;
-         }
-         break;
-#endif
-
-      default:
-         /* Standard cases where no compositing is done (so the component
-          * value is already correct.)
-          */
-         break;
-   }
-
-   return input_sample;
-}
-
-/* This API returns the encoded *input* component, in the range 0..1 */
-static double
-gamma_component_validate(PNG_CONST char *name, PNG_CONST validate_info *vi,
-    PNG_CONST unsigned int id, PNG_CONST unsigned int od,
-    PNG_CONST double alpha /* <0 for the alpha channel itself */,
-    PNG_CONST double background /* component background value */)
-{
-   PNG_CONST unsigned int isbit = id >> vi->isbit_shift;
-   PNG_CONST unsigned int sbit_max = vi->sbit_max;
-   PNG_CONST unsigned int outmax = vi->outmax;
-   PNG_CONST int do_background = vi->do_background;
-
-   double i;
-
-   /* First check on the 'perfect' result obtained from the digitized input
-    * value, id, and compare this against the actual digitized result, 'od'.
-    * 'i' is the input result in the range 0..1:
-    */
-   i = isbit; i /= sbit_max;
-
-   /* Check for the fast route: if we don't do any background composition or if
-    * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
-    * just use the gamma_correction field to correct to the final output gamma.
-    */
-   if (alpha == 1 /* opaque pixel component */ || !do_background
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-      || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
-#endif
-      || (alpha < 0 /* alpha channel */
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-      && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
-#endif
-      ))
-   {
-      /* Then get the gamma corrected version of 'i' and compare to 'od', any
-       * error less than .5 is insignificant - just quantization of the output
-       * value to the nearest digital value (nevertheless the error is still
-       * recorded - it's interesting ;-)
-       */
-      double encoded_sample = i;
-      double encoded_error;
-
-      /* alpha less than 0 indicates the alpha channel, which is always linear
-       */
-      if (alpha >= 0 && vi->gamma_correction > 0)
-         encoded_sample = pow(encoded_sample, vi->gamma_correction);
-      encoded_sample *= outmax;
-
-      encoded_error = fabs(od-encoded_sample);
-
-      if (encoded_error > vi->dp->maxerrout)
-         vi->dp->maxerrout = encoded_error;
-
-      if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
-         return i;
-   }
-
-   /* The slow route - attempt to do linear calculations. */
-   /* There may be an error, or background processing is required, so calculate
-    * the actual sample values - unencoded light intensity values.  Note that in
-    * practice these are not completely unencoded because they include a
-    * 'viewing correction' to decrease or (normally) increase the perceptual
-    * contrast of the image.  There's nothing we can do about this - we don't
-    * know what it is - so assume the unencoded value is perceptually linear.
-    */
-   {
-      double input_sample = i; /* In range 0..1 */
-      double output, error, encoded_sample, encoded_error;
-      double es_lo, es_hi;
-      int compose = 0;           /* Set to one if composition done */
-      int output_is_encoded;     /* Set if encoded to screen gamma */
-      int log_max_error = 1;     /* Check maximum error values */
-      png_const_charp pass = 0;  /* Reason test passes (or 0 for fail) */
-
-      /* Convert to linear light (with the above caveat.)  The alpha channel is
-       * already linear.
-       */
-      if (alpha >= 0)
-      {
-         int tcompose;
-
-         if (vi->file_inverse > 0)
-            input_sample = pow(input_sample, vi->file_inverse);
-
-         /* Handle the compose processing: */
-         tcompose = 0;
-         input_sample = gamma_component_compose(do_background, input_sample,
-            alpha, background, &tcompose);
-
-         if (tcompose)
-            compose = 1;
-      }
-
-      /* And similarly for the output value, but we need to check the background
-       * handling to linearize it correctly.
-       */
-      output = od;
-      output /= outmax;
-
-      output_is_encoded = vi->screen_gamma > 0;
-
-      if (alpha < 0) /* The alpha channel */
-      {
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-         if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
-#endif
-         {
-            /* In all other cases the output alpha channel is linear already,
-             * don't log errors here, they are much larger in linear data.
-             */
-            output_is_encoded = 0;
-            log_max_error = 0;
-         }
-      }
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-      else /* A component */
-      {
-         if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
-            alpha < 1) /* the optimized case - linear output */
-         {
-            if (alpha > 0) log_max_error = 0;
-            output_is_encoded = 0;
-         }
-      }
-#endif
-
-      if (output_is_encoded)
-         output = pow(output, vi->screen_gamma);
-
-      /* Calculate (or recalculate) the encoded_sample value and repeat the
-       * check above (unnecessary if we took the fast route, but harmless.)
-       */
-      encoded_sample = input_sample;
-      if (output_is_encoded)
-         encoded_sample = pow(encoded_sample, vi->screen_inverse);
-      encoded_sample *= outmax;
-
-      encoded_error = fabs(od-encoded_sample);
-
-      /* Don't log errors in the alpha channel, or the 'optimized' case,
-       * neither are significant to the overall perception.
-       */
-      if (log_max_error && encoded_error > vi->dp->maxerrout)
-         vi->dp->maxerrout = encoded_error;
-
-      if (encoded_error < vi->maxout_total)
-      {
-         if (encoded_error < vi->outlog)
-            return i;
-
-         /* Test passed but error is bigger than the log limit, record why the
-          * test passed:
-          */
-         pass = "less than maxout:\n";
-      }
-
-      /* i: the original input value in the range 0..1
-       *
-       * pngvalid calculations:
-       *  input_sample: linear result; i linearized and composed, range 0..1
-       *  encoded_sample: encoded result; input_sample scaled to ouput bit depth
-       *
-       * libpng calculations:
-       *  output: linear result; od scaled to 0..1 and linearized
-       *  od: encoded result from libpng
-       */
-
-      /* Now we have the numbers for real errors, both absolute values as as a
-       * percentage of the correct value (output):
-       */
-      error = fabs(input_sample-output);
-
-      if (log_max_error && error > vi->dp->maxerrabs)
-         vi->dp->maxerrabs = error;
-
-      /* The following is an attempt to ignore the tendency of quantization to
-       * dominate the percentage errors for lower result values:
-       */
-      if (log_max_error && input_sample > .5)
-      {
-         double percentage_error = error/input_sample;
-         if (percentage_error > vi->dp->maxerrpc)
-            vi->dp->maxerrpc = percentage_error;
-      }
-
-      /* Now calculate the digitization limits for 'encoded_sample' using the
-       * 'max' values.  Note that maxout is in the encoded space but maxpc and
-       * maxabs are in linear light space.
-       *
-       * First find the maximum error in linear light space, range 0..1:
-       */
-      {
-         double tmp = input_sample * vi->maxpc;
-         if (tmp < vi->maxabs) tmp = vi->maxabs;
-         /* If 'compose' is true the composition was done in linear space using
-          * integer arithmetic.  This introduces an extra error of +/- 0.5 (at
-          * least) in the integer space used.  'maxcalc' records this, taking
-          * into account the possibility that even for 16 bit output 8 bit space
-          * may have been used.
-          */
-         if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
-
-         /* The 'maxout' value refers to the encoded result, to compare with
-          * this encode input_sample adjusted by the maximum error (tmp) above.
-          */
-         es_lo = encoded_sample - vi->maxout;
-
-         if (es_lo > 0 && input_sample-tmp > 0)
-         {
-            double low_value = input_sample-tmp;
-            if (output_is_encoded)
-               low_value = pow(low_value, vi->screen_inverse);
-            low_value *= outmax;
-            if (low_value < es_lo) es_lo = low_value;
-
-            /* Quantize this appropriately: */
-            es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
-         }
-
-         else
-            es_lo = 0;
-
-         es_hi = encoded_sample + vi->maxout;
-
-         if (es_hi < outmax && input_sample+tmp < 1)
-         {
-            double high_value = input_sample+tmp;
-            if (output_is_encoded)
-               high_value = pow(high_value, vi->screen_inverse);
-            high_value *= outmax;
-            if (high_value > es_hi) es_hi = high_value;
-
-            es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
-         }
-
-         else
-            es_hi = outmax;
-      }
-
-      /* The primary test is that the final encoded value returned by the
-       * library should be between the two limits (inclusive) that were
-       * calculated above.
-       */
-      if (od >= es_lo && od <= es_hi)
-      {
-         /* The value passes, but we may need to log the information anyway. */
-         if (encoded_error < vi->outlog)
-            return i;
-
-         if (pass == 0)
-            pass = "within digitization limits:\n";
-      }
-
-      {
-         /* There has been an error in processing, or we need to log this
-          * value.
-          */
-         double is_lo, is_hi;
-
-         /* pass is set at this point if either of the tests above would have
-          * passed.  Don't do these additional tests here - just log the
-          * original [es_lo..es_hi] values.
-          */
-         if (pass == 0 && vi->use_input_precision)
-         {
-            /* Ok, something is wrong - this actually happens in current libpng
-             * 16-to-8 processing.  Assume that the input value (id, adjusted
-             * for sbit) can be anywhere between value-.5 and value+.5 - quite a
-             * large range if sbit is low.
-             */
-            double tmp = (isbit - .5)/sbit_max;
-
-            if (tmp <= 0)
-               tmp = 0;
-
-            else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
-               tmp = pow(tmp, vi->file_inverse);
-
-            tmp = gamma_component_compose(do_background, tmp, alpha, background,
-               NULL);
-
-            if (output_is_encoded && tmp > 0 && tmp < 1)
-               tmp = pow(tmp, vi->screen_inverse);
-
-            is_lo = ceil(outmax * tmp - vi->maxout_total);
-
-            if (is_lo < 0)
-               is_lo = 0;
-
-            tmp = (isbit + .5)/sbit_max;
-
-            if (tmp <= 0)
-               tmp = 0;
-
-            else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
-               tmp = pow(tmp, vi->file_inverse);
-
-            tmp = gamma_component_compose(do_background, tmp, alpha, background,
-               NULL);
-
-            if (output_is_encoded && tmp > 0 && tmp < 1)
-               tmp = pow(tmp, vi->screen_inverse);
-
-            is_hi = floor(outmax * tmp + vi->maxout_total);
-
-            if (is_hi > outmax)
-               is_hi = outmax;
-
-            if (!(od < is_lo || od > is_hi))
-            {
-               if (encoded_error < vi->outlog)
-                  return i;
-
-               pass = "within input precision limits:\n";
-            }
-
-            /* One last chance.  If this is an alpha channel and the 16to8
-             * option has been used and 'inaccurate' scaling is used then the
-             * bit reduction is obtained by simply using the top 8 bits of the
-             * value.
-             *
-             * This is only done for older libpng versions when the 'inaccurate'
-             * (chop) method of scaling was used.
-             */
-#           ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
-#              if PNG_LIBPNG_VER < 10504
-                  /* This may be required for other components in the future,
-                   * but at present the presence of gamma correction effectively
-                   * prevents the errors in the component scaling (I don't quite
-                   * understand why, but since it's better this way I care not
-                   * to ask, JB 20110419.)
-                   */
-                  if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
-                     vi->sbit + vi->isbit_shift == 16)
-                  {
-                     tmp = ((id >> 8) - .5)/255;
-
-                     if (tmp > 0)
-                     {
-                        is_lo = ceil(outmax * tmp - vi->maxout_total);
-                        if (is_lo < 0) is_lo = 0;
-                     }
-
-                     else
-                        is_lo = 0;
-
-                     tmp = ((id >> 8) + .5)/255;
-
-                     if (tmp < 1)
-                     {
-                        is_hi = floor(outmax * tmp + vi->maxout_total);
-                        if (is_hi > outmax) is_hi = outmax;
-                     }
-
-                     else
-                        is_hi = outmax;
-
-                     if (!(od < is_lo || od > is_hi))
-                     {
-                        if (encoded_error < vi->outlog)
-                           return i;
-
-                        pass = "within 8 bit limits:\n";
-                     }
-                  }
-#              endif
-#           endif
-         }
-         else /* !use_input_precision */
-            is_lo = es_lo, is_hi = es_hi;
-
-         /* Attempt to output a meaningful error/warning message: the message
-          * output depends on the background/composite operation being performed
-          * because this changes what parameters were actually used above.
-          */
-         {
-            size_t pos = 0;
-            /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
-             * places.  Just use outmax to work out which.
-             */
-            int precision = (outmax >= 1000 ? 6 : 3);
-            int use_input=1, use_background=0, do_compose=0;
-            char msg[256];
-
-            if (pass != 0)
-               pos = safecat(msg, sizeof msg, pos, "\n\t");
-
-            /* Set up the various flags, the output_is_encoded flag above
-             * is also used below.  do_compose is just a double check.
-             */
-            switch (do_background)
-            {
-            case PNG_BACKGROUND_GAMMA_SCREEN:
-            case PNG_BACKGROUND_GAMMA_FILE:
-            case PNG_BACKGROUND_GAMMA_UNIQUE:
-               use_background = (alpha >= 0 && alpha < 1);
-               /*FALL THROUGH*/
-#           ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-               case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
-               case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
-               case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
-#           endif /* ALPHA_MODE_SUPPORTED */
-               do_compose = (alpha > 0 && alpha < 1);
-               use_input = (alpha != 0);
-               break;
-
-            default:
-               break;
-            }
-
-            /* Check the 'compose' flag */
-            if (compose != do_compose)
-               png_error(vi->pp, "internal error (compose)");
-
-            /* 'name' is the component name */
-            pos = safecat(msg, sizeof msg, pos, name);
-            pos = safecat(msg, sizeof msg, pos, "(");
-            pos = safecatn(msg, sizeof msg, pos, id);
-            if (use_input || pass != 0/*logging*/)
-            {
-               if (isbit != id)
-               {
-                  /* sBIT has reduced the precision of the input: */
-                  pos = safecat(msg, sizeof msg, pos, ", sbit(");
-                  pos = safecatn(msg, sizeof msg, pos, vi->sbit);
-                  pos = safecat(msg, sizeof msg, pos, "): ");
-                  pos = safecatn(msg, sizeof msg, pos, isbit);
-               }
-               pos = safecat(msg, sizeof msg, pos, "/");
-               /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
-               pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
-            }
-            pos = safecat(msg, sizeof msg, pos, ")");
-
-            /* A component may have been multiplied (in linear space) by the
-             * alpha value, 'compose' says whether this is relevant.
-             */
-            if (compose || pass != 0)
-            {
-               /* If any form of composition is being done report our
-                * calculated linear value here (the code above doesn't record
-                * the input value before composition is performed, so what
-                * gets reported is the value after composition.)
-                */
-               if (use_input || pass != 0)
-               {
-                  if (vi->file_inverse > 0)
-                  {
-                     pos = safecat(msg, sizeof msg, pos, "^");
-                     pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
-                  }
-
-                  else
-                     pos = safecat(msg, sizeof msg, pos, "[linear]");
-
-                  pos = safecat(msg, sizeof msg, pos, "*(alpha)");
-                  pos = safecatd(msg, sizeof msg, pos, alpha, precision);
-               }
-
-               /* Now record the *linear* background value if it was used
-                * (this function is not passed the original, non-linear,
-                * value but it is contained in the test name.)
-                */
-               if (use_background)
-               {
-                  pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
-                  pos = safecat(msg, sizeof msg, pos, "(background)");
-                  pos = safecatd(msg, sizeof msg, pos, background, precision);
-                  pos = safecat(msg, sizeof msg, pos, "*");
-                  pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
-               }
-            }
-
-            /* Report the calculated value (input_sample) and the linearized
-             * libpng value (output) unless this is just a component gamma
-             * correction.
-             */
-            if (compose || alpha < 0 || pass != 0)
-            {
-               pos = safecat(msg, sizeof msg, pos,
-                  pass != 0 ? " =\n\t" : " = ");
-               pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
-               pos = safecat(msg, sizeof msg, pos, " (libpng: ");
-               pos = safecatd(msg, sizeof msg, pos, output, precision);
-               pos = safecat(msg, sizeof msg, pos, ")");
-
-               /* Finally report the output gamma encoding, if any. */
-               if (output_is_encoded)
-               {
-                  pos = safecat(msg, sizeof msg, pos, " ^");
-                  pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
-                  pos = safecat(msg, sizeof msg, pos, "(to screen) =");
-               }
-
-               else
-                  pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
-            }
-
-            if ((!compose && alpha >= 0) || pass != 0)
-            {
-               if (pass != 0) /* logging */
-                  pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
-
-               /* This is the non-composition case, the internal linear
-                * values are irrelevant (though the log below will reveal
-                * them.)  Output a much shorter warning/error message and report
-                * the overall gamma correction.
-                */
-               if (vi->gamma_correction > 0)
-               {
-                  pos = safecat(msg, sizeof msg, pos, " ^");
-                  pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
-                  pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
-               }
-
-               else
-                  pos = safecat(msg, sizeof msg, pos,
-                     " [no gamma correction] =");
-
-               if (pass != 0)
-                  pos = safecat(msg, sizeof msg, pos, "]");
-            }
-
-            /* This is our calculated encoded_sample which should (but does
-             * not) match od:
-             */
-            pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
-            pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
-            pos = safecat(msg, sizeof msg, pos, " < ");
-            pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
-            pos = safecat(msg, sizeof msg, pos, " (libpng: ");
-            pos = safecatn(msg, sizeof msg, pos, od);
-            pos = safecat(msg, sizeof msg, pos, ")");
-            pos = safecat(msg, sizeof msg, pos, "/");
-            pos = safecatn(msg, sizeof msg, pos, outmax);
-            pos = safecat(msg, sizeof msg, pos, " < ");
-            pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
-
-            if (pass == 0) /* The error condition */
-            {
-#              ifdef PNG_WARNINGS_SUPPORTED
-                  png_warning(vi->pp, msg);
-#              else
-                  store_warning(vi->pp, msg);
-#              endif
-            }
-
-            else /* logging this value */
-               store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
-         }
-      }
-   }
-
-   return i;
-}
-
-static void
-gamma_image_validate(gamma_display *dp, png_structp pp, png_infop pi)
-{
-   /* Get some constants derived from the input and output file formats: */
-   PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
-   PNG_CONST png_byte in_ct = dp->this.colour_type;
-   PNG_CONST png_byte in_bd = dp->this.bit_depth;
-   PNG_CONST png_uint_32 w = dp->this.w;
-   PNG_CONST png_uint_32 h = dp->this.h;
-   PNG_CONST size_t cbRow = dp->this.cbRow;
-   PNG_CONST png_byte out_ct = png_get_color_type(pp, pi);
-   PNG_CONST png_byte out_bd = png_get_bit_depth(pp, pi);
-
-   /* There are three sources of error, firstly the quantization in the
-    * file encoding, determined by sbit and/or the file depth, secondly
-    * the output (screen) gamma and thirdly the output file encoding.
-    *
-    * Since this API receives the screen and file gamma in double
-    * precision it is possible to calculate an exact answer given an input
-    * pixel value.  Therefore we assume that the *input* value is exact -
-    * sample/maxsample - calculate the corresponding gamma corrected
-    * output to the limits of double precision arithmetic and compare with
-    * what libpng returns.
-    *
-    * Since the library must quantize the output to 8 or 16 bits there is
-    * a fundamental limit on the accuracy of the output of +/-.5 - this
-    * quantization limit is included in addition to the other limits
-    * specified by the paramaters to the API.  (Effectively, add .5
-    * everywhere.)
-    *
-    * The behavior of the 'sbit' paramter is defined by section 12.5
-    * (sample depth scaling) of the PNG spec.  That section forces the
-    * decoder to assume that the PNG values have been scaled if sBIT is
-    * present:
-    *
-    *     png-sample = floor( input-sample * (max-out/max-in) + .5);
-    *
-    * This means that only a subset of the possible PNG values should
-    * appear in the input. However, the spec allows the encoder to use a
-    * variety of approximations to the above and doesn't require any
-    * restriction of the values produced.
-    *
-    * Nevertheless the spec requires that the upper 'sBIT' bits of the
-    * value stored in a PNG file be the original sample bits.
-    * Consequently the code below simply scales the top sbit bits by
-    * (1<<sbit)-1 to obtain an original sample value.
-    *
-    * Because there is limited precision in the input it is arguable that
-    * an acceptable result is any valid result from input-.5 to input+.5.
-    * The basic tests below do not do this, however if 'use_input_precision'
-    * is set a subsequent test is performed below.
-    */
-   PNG_CONST unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
-   int processing;
-   png_uint_32 y;
-   PNG_CONST store_palette_entry *in_palette = dp->this.palette;
-   PNG_CONST int in_is_transparent = dp->this.is_transparent;
-   int out_npalette = -1;
-   int out_is_transparent = 0; /* Just refers to the palette case */
-   store_palette out_palette;
-   validate_info vi;
-
-   /* Check for row overwrite errors */
-   store_image_check(dp->this.ps, pp, 0);
-
-   /* Supply the input and output sample depths here - 8 for an indexed image,
-    * otherwise the bit depth.
-    */
-   init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
-
-   processing = (vi.gamma_correction > 0 && !dp->threshold_test)
-      || in_bd != out_bd || in_ct != out_ct || vi.do_background;
-
-   /* TODO: FIX THIS: MAJOR BUG!  If the transformations all happen inside
-    * the palette there is no way of finding out, because libpng fails to
-    * update the palette on png_read_update_info.  Indeed, libpng doesn't
-    * even do the required work until much later, when it doesn't have any
-    * info pointer.  Oops.  For the moment 'processing' is turned off if
-    * out_ct is palette.
-    */
-   if (in_ct == 3 && out_ct == 3)
-      processing = 0;
-
-   if (processing && out_ct == 3)
-      out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
-
-   for (y=0; y<h; ++y)
-   {
-      png_const_bytep pRow = store_image_row(ps, pp, 0, y);
-      png_byte std[STANDARD_ROWMAX];
-
-      transform_row(pp, std, in_ct, in_bd, y);
-
-      if (processing)
-      {
-         unsigned int x;
-
-         for (x=0; x<w; ++x)
-         {
-            double alpha = 1; /* serves as a flag value */
-
-            /* Record the palette index for index images. */
-            PNG_CONST unsigned int in_index =
-               in_ct == 3 ? sample(std, 3, in_bd, x, 0) : 256;
-            PNG_CONST unsigned int out_index =
-               out_ct == 3 ? sample(std, 3, out_bd, x, 0) : 256;
-
-            /* Handle input alpha - png_set_background will cause the output
-             * alpha to disappear so there is nothing to check.
-             */
-            if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 || (in_ct == 3 &&
-               in_is_transparent))
-            {
-               PNG_CONST unsigned int input_alpha = in_ct == 3 ?
-                  dp->this.palette[in_index].alpha :
-                  sample(std, in_ct, in_bd, x, samples_per_pixel);
-
-               unsigned int output_alpha = 65536 /* as a flag value */;
-
-               if (out_ct == 3)
-               {
-                  if (out_is_transparent)
-                     output_alpha = out_palette[out_index].alpha;
-               }
-
-               else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
-                  output_alpha = sample(pRow, out_ct, out_bd, x,
-                     samples_per_pixel);
-
-               if (output_alpha != 65536)
-                  alpha = gamma_component_validate("alpha", &vi, input_alpha,
-                     output_alpha, -1/*alpha*/, 0/*background*/);
-
-               else /* no alpha in output */
-               {
-                  /* This is a copy of the calculation of 'i' above in order to
-                   * have the alpha value to use in the background calculation.
-                   */
-                  alpha = input_alpha >> vi.isbit_shift;
-                  alpha /= vi.sbit_max;
-               }
-            }
-
-            /* Handle grayscale or RGB components. */
-            if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
-               (void)gamma_component_validate("gray", &vi,
-                  sample(std, in_ct, in_bd, x, 0),
-                  sample(pRow, out_ct, out_bd, x, 0), alpha/*component*/,
-                  vi.background_red);
-            else /* RGB or palette */
-            {
-               (void)gamma_component_validate("red", &vi,
-                  in_ct == 3 ? in_palette[in_index].red :
-                     sample(std, in_ct, in_bd, x, 0),
-                  out_ct == 3 ? out_palette[out_index].red :
-                     sample(pRow, out_ct, out_bd, x, 0),
-                  alpha/*component*/, vi.background_red);
-
-               (void)gamma_component_validate("green", &vi,
-                  in_ct == 3 ? in_palette[in_index].green :
-                     sample(std, in_ct, in_bd, x, 1),
-                  out_ct == 3 ? out_palette[out_index].green :
-                     sample(pRow, out_ct, out_bd, x, 1),
-                  alpha/*component*/, vi.background_green);
-
-               (void)gamma_component_validate("blue", &vi,
-                  in_ct == 3 ? in_palette[in_index].blue :
-                     sample(std, in_ct, in_bd, x, 2),
-                  out_ct == 3 ? out_palette[out_index].blue :
-                     sample(pRow, out_ct, out_bd, x, 2),
-                  alpha/*component*/, vi.background_blue);
-            }
-         }
-      }
-
-      else if (memcmp(std, pRow, cbRow) != 0)
-      {
-         char msg[64];
-
-         /* No transform is expected on the threshold tests. */
-         sprintf(msg, "gamma: below threshold row %d changed", y);
-
-         png_error(pp, msg);
-      }
-   } /* row (y) loop */
-
-   dp->this.ps->validated = 1;
-}
-
-static void
-gamma_end(png_structp pp, png_infop pi)
-{
-   gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
-
-   if (!dp->this.speed)
-      gamma_image_validate(dp, pp, pi);
-   else
-      dp->this.ps->validated = 1;
-}
-
-/* A single test run checking a gamma transformation.
- *
- * maxabs: maximum absolute error as a fraction
- * maxout: maximum output error in the output units
- * maxpc:  maximum percentage error (as a percentage)
- */
-static void
-gamma_test(png_modifier *pmIn, PNG_CONST png_byte colour_typeIn,
-    PNG_CONST png_byte bit_depthIn, PNG_CONST int palette_numberIn,
-    PNG_CONST int interlace_typeIn,
-    PNG_CONST double file_gammaIn, PNG_CONST double screen_gammaIn,
-    PNG_CONST png_byte sbitIn, PNG_CONST int threshold_testIn,
-    PNG_CONST char *name,
-    PNG_CONST int use_input_precisionIn, PNG_CONST int scale16In,
-    PNG_CONST int expand16In, PNG_CONST int do_backgroundIn,
-    PNG_CONST png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
-{
-   gamma_display d;
-   context(&pmIn->this, fault);
-
-   gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
-      palette_numberIn, interlace_typeIn, 0, 0, 0),
-      file_gammaIn, screen_gammaIn, sbitIn,
-      threshold_testIn, use_input_precisionIn, scale16In,
-      expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
-
-   Try
-   {
-      png_structp pp;
-      png_infop pi;
-      gama_modification gama_mod;
-      srgb_modification srgb_mod;
-      sbit_modification sbit_mod;
-
-      /* For the moment don't use the png_modifier support here. */
-      d.pm->encoding_counter = 0;
-      modifier_set_encoding(d.pm); /* Just resets everything */
-      d.pm->current_gamma = d.file_gamma;
-
-      /* Make an appropriate modifier to set the PNG file gamma to the
-       * given gamma value and the sBIT chunk to the given precision.
-       */
-      d.pm->modifications = NULL;
-      gama_modification_init(&gama_mod, d.pm, d.file_gamma);
-      srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
-      if (d.sbit > 0)
-         sbit_modification_init(&sbit_mod, d.pm, d.sbit);
-
-      modification_reset(d.pm->modifications);
-
-      /* Get a png_struct for writing the image. */
-      pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
-      standard_palette_init(&d.this);
-
-      /* Introduce the correct read function. */
-      if (d.pm->this.progressive)
-      {
-         /* Share the row function with the standard implementation. */
-         png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
-            gamma_end);
-
-         /* Now feed data into the reader until we reach the end: */
-         modifier_progressive_read(d.pm, pp, pi);
-      }
-      else
-      {
-         /* modifier_read expects a png_modifier* */
-         png_set_read_fn(pp, d.pm, modifier_read);
-
-         /* Check the header values: */
-         png_read_info(pp, pi);
-
-         /* Process the 'info' requirements. Only one image is generated */
-         gamma_info_imp(&d, pp, pi);
-
-         sequential_row(&d.this, pp, pi, -1, 0);
-
-         if (!d.this.speed)
-            gamma_image_validate(&d, pp, pi);
-         else
-            d.this.ps->validated = 1;
-      }
-
-      modifier_reset(d.pm);
-
-      if (d.pm->log && !d.threshold_test && !d.this.speed)
-         fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
-            d.this.bit_depth, colour_types[d.this.colour_type], name,
-            d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
-
-      /* Log the summary values too. */
-      if (d.this.colour_type == 0 || d.this.colour_type == 4)
-      {
-         switch (d.this.bit_depth)
-         {
-         case 1:
-            break;
-
-         case 2:
-            if (d.maxerrout > d.pm->error_gray_2)
-               d.pm->error_gray_2 = d.maxerrout;
-
-            break;
-
-         case 4:
-            if (d.maxerrout > d.pm->error_gray_4)
-               d.pm->error_gray_4 = d.maxerrout;
-
-            break;
-
-         case 8:
-            if (d.maxerrout > d.pm->error_gray_8)
-               d.pm->error_gray_8 = d.maxerrout;
-
-            break;
-
-         case 16:
-            if (d.maxerrout > d.pm->error_gray_16)
-               d.pm->error_gray_16 = d.maxerrout;
-
-            break;
-
-         default:
-            png_error(pp, "bad bit depth (internal: 1)");
-         }
-      }
-
-      else if (d.this.colour_type == 2 || d.this.colour_type == 6)
-      {
-         switch (d.this.bit_depth)
-         {
-         case 8:
-
-            if (d.maxerrout > d.pm->error_color_8)
-               d.pm->error_color_8 = d.maxerrout;
-
-            break;
-
-         case 16:
-
-            if (d.maxerrout > d.pm->error_color_16)
-               d.pm->error_color_16 = d.maxerrout;
-
-            break;
-
-         default:
-            png_error(pp, "bad bit depth (internal: 2)");
-         }
-      }
-
-      else if (d.this.colour_type == 3)
-      {
-         if (d.maxerrout > d.pm->error_indexed)
-            d.pm->error_indexed = d.maxerrout;
-      }
-   }
-
-   Catch(fault)
-      modifier_reset((png_modifier*)fault);
-}
-
-static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
-    png_byte bit_depth, int interlace_type, double file_gamma,
-    double screen_gamma)
-{
-   size_t pos = 0;
-   char name[64];
-   pos = safecat(name, sizeof name, pos, "threshold ");
-   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
-   pos = safecat(name, sizeof name, pos, "/");
-   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
-
-   (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
-      file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
-      0 /*no input precision*/,
-      0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
-      0 /*no background gamma*/);
-}
-
-static void
-perform_gamma_threshold_tests(png_modifier *pm)
-{
-   png_byte colour_type = 0;
-   png_byte bit_depth = 0;
-   int palette_number = 0;
-
-   /* Don't test more than one instance of each palette - it's pointless, in
-    * fact this test is somewhat excessive since libpng doesn't make this
-    * decision based on colour type or bit depth!
-    */
-   while (next_format(&colour_type, &bit_depth, &palette_number))
-      if (palette_number == 0)
-   {
-      double test_gamma = 1.0;
-      while (test_gamma >= .4)
-      {
-         /* There's little point testing the interlacing vs non-interlacing,
-          * but this can be set from the command line.
-          */
-         gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
-            test_gamma, 1/test_gamma);
-         test_gamma *= .95;
-      }
-
-      /* And a special test for sRGB */
-      gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
-          .45455, 2.2);
-
-      if (fail(pm))
-         return;
-   }
-}
-
-static void gamma_transform_test(png_modifier *pm,
-   PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
-   PNG_CONST int palette_number,
-   PNG_CONST int interlace_type, PNG_CONST double file_gamma,
-   PNG_CONST double screen_gamma, PNG_CONST png_byte sbit,
-   PNG_CONST int use_input_precision, PNG_CONST int scale16)
-{
-   size_t pos = 0;
-   char name[64];
-
-   if (sbit != bit_depth && sbit != 0)
-   {
-      pos = safecat(name, sizeof name, pos, "sbit(");
-      pos = safecatn(name, sizeof name, pos, sbit);
-      pos = safecat(name, sizeof name, pos, ") ");
-   }
-
-   else
-      pos = safecat(name, sizeof name, pos, "gamma ");
-
-   if (scale16)
-      pos = safecat(name, sizeof name, pos, "16to8 ");
-
-   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
-   pos = safecat(name, sizeof name, pos, "->");
-   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
-
-   gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
-      file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
-      scale16, pm->test_gamma_expand16, 0 , 0, 0);
-}
-
-static void perform_gamma_transform_tests(png_modifier *pm)
-{
-   png_byte colour_type = 0;
-   png_byte bit_depth = 0;
-   int palette_number = 0;
-
-   while (next_format(&colour_type, &bit_depth, &palette_number))
-   {
-      unsigned int i, j;
-
-      for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
-         if (i != j)
-         {
-            gamma_transform_test(pm, colour_type, bit_depth, palette_number,
-               pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], 0/*sBIT*/,
-               pm->use_input_precision, 0 /*do not scale16*/);
-
-            if (fail(pm))
-               return;
-         }
-   }
-}
-
-static void perform_gamma_sbit_tests(png_modifier *pm)
-{
-   png_byte sbit;
-
-   /* The only interesting cases are colour and grayscale, alpha is ignored here
-    * for overall speed.  Only bit depths where sbit is less than the bit depth
-    * are tested.
-    */
-   for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
-   {
-      png_byte colour_type, bit_depth;
-      int npalette;
-
-      colour_type = bit_depth = 0;
-      npalette = 0;
-
-      while (next_format(&colour_type, &bit_depth, &npalette))
-         if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
-            ((colour_type == 3 && sbit < 8) ||
-            (colour_type != 3 && sbit < bit_depth)))
-      {
-         unsigned int i;
-
-         for (i=0; i<pm->ngamma_tests; ++i)
-         {
-            unsigned int j;
-
-            for (j=0; j<pm->ngamma_tests; ++j) if (i != j)
-            {
-               gamma_transform_test(pm, colour_type, bit_depth, npalette,
-                  pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
-                  sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
-
-               if (fail(pm))
-                  return;
-            }
-         }
-      }
-   }
-}
-
-/* Note that this requires a 16 bit source image but produces 8 bit output, so
- * we only need the 16bit write support, but the 16 bit images are only
- * generated if DO_16BIT is defined.
- */
-#ifdef DO_16BIT
-static void perform_gamma_scale16_tests(png_modifier *pm)
-{
-#  ifndef PNG_MAX_GAMMA_8
-#     define PNG_MAX_GAMMA_8 11
-#  endif
-   /* Include the alpha cases here. Note that sbit matches the internal value
-    * used by the library - otherwise we will get spurious errors from the
-    * internal sbit style approximation.
-    *
-    * The threshold test is here because otherwise the 16 to 8 conversion will
-    * proceed *without* gamma correction, and the tests above will fail (but not
-    * by much) - this could be fixed, it only appears with the -g option.
-    */
-   unsigned int i, j;
-   for (i=0; i<pm->ngamma_tests; ++i)
-   {
-      for (j=0; j<pm->ngamma_tests; ++j)
-      {
-         if (i != j &&
-             fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
-         {
-            gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
-               1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
-               pm->use_input_precision_16to8, 1 /*scale16*/);
-
-            if (fail(pm))
-               return;
-
-            gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
-               1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
-               pm->use_input_precision_16to8, 1 /*scale16*/);
-
-            if (fail(pm))
-               return;
-
-            gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
-               1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
-               pm->use_input_precision_16to8, 1 /*scale16*/);
-
-            if (fail(pm))
-               return;
-
-            gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
-               1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
-               pm->use_input_precision_16to8, 1 /*scale16*/);
-
-            if (fail(pm))
-               return;
-         }
-      }
-   }
-}
-#endif /* 16 to 8 bit conversion */
-
-#if defined PNG_READ_BACKGROUND_SUPPORTED ||\
-   defined PNG_READ_ALPHA_MODE_SUPPORTED
-static void gamma_composition_test(png_modifier *pm,
-   PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
-   PNG_CONST int palette_number,
-   PNG_CONST int interlace_type, PNG_CONST double file_gamma,
-   PNG_CONST double screen_gamma,
-   PNG_CONST int use_input_precision, PNG_CONST int do_background,
-   PNG_CONST int expand_16)
-{
-   size_t pos = 0;
-   png_const_charp base;
-   double bg;
-   char name[128];
-   png_color_16 background;
-
-   /* Make up a name and get an appropriate background gamma value. */
-   switch (do_background)
-   {
-      default:
-         base = "";
-         bg = 4; /* should not be used */
-         break;
-      case PNG_BACKGROUND_GAMMA_SCREEN:
-         base = " bckg(Screen):";
-         bg = 1/screen_gamma;
-         break;
-      case PNG_BACKGROUND_GAMMA_FILE:
-         base = " bckg(File):";
-         bg = file_gamma;
-         break;
-      case PNG_BACKGROUND_GAMMA_UNIQUE:
-         base = " bckg(Unique):";
-         /* This tests the handling of a unique value, the math is such that the
-          * value tends to be <1, but is neither screen nor file (even if they
-          * match!)
-          */
-         bg = (file_gamma + screen_gamma) / 3;
-         break;
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-      case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
-         base = " alpha(PNG)";
-         bg = 4; /* should not be used */
-         break;
-      case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
-         base = " alpha(Porter-Duff)";
-         bg = 4; /* should not be used */
-         break;
-      case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
-         base = " alpha(Optimized)";
-         bg = 4; /* should not be used */
-         break;
-      case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
-         base = " alpha(Broken)";
-         bg = 4; /* should not be used */
-         break;
-#endif
-   }
-
-   /* Use random background values - the background is always presented in the
-    * output space (8 or 16 bit components).
-    */
-   if (expand_16 || bit_depth == 16)
-   {
-      png_uint_32 r = random_32();
-
-      background.red = (png_uint_16)r;
-      background.green = (png_uint_16)(r >> 16);
-      r = random_32();
-      background.blue = (png_uint_16)r;
-      background.gray = (png_uint_16)(r >> 16);
-   }
-
-   else /* 8 bit colors */
-   {
-      png_uint_32 r = random_32();
-
-      background.red = (png_byte)r;
-      background.green = (png_byte)(r >> 8);
-      background.blue = (png_byte)(r >> 16);
-      background.gray = (png_byte)(r >> 24);
-   }
-
-   background.index = 193; /* rgb(193,193,193) to detect errors */
-   if (!(colour_type & PNG_COLOR_MASK_COLOR))
-   {
-      /* Grayscale input, we do not convert to RGB (TBD), so we must set the
-       * background to gray - else libpng seems to fail.
-       */
-      background.red = background.green = background.blue = background.gray;
-   }
-
-   pos = safecat(name, sizeof name, pos, "gamma ");
-   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
-   pos = safecat(name, sizeof name, pos, "->");
-   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
-
-   pos = safecat(name, sizeof name, pos, base);
-   if (do_background < ALPHA_MODE_OFFSET)
-   {
-      /* Include the background color and gamma in the name: */
-      pos = safecat(name, sizeof name, pos, "(");
-      /* This assumes no expand gray->rgb - the current code won't handle that!
-       */
-      if (colour_type & PNG_COLOR_MASK_COLOR)
-      {
-         pos = safecatn(name, sizeof name, pos, background.red);
-         pos = safecat(name, sizeof name, pos, ",");
-         pos = safecatn(name, sizeof name, pos, background.green);
-         pos = safecat(name, sizeof name, pos, ",");
-         pos = safecatn(name, sizeof name, pos, background.blue);
-      }
-      else
-         pos = safecatn(name, sizeof name, pos, background.gray);
-      pos = safecat(name, sizeof name, pos, ")^");
-      pos = safecatd(name, sizeof name, pos, bg, 3);
-   }
-
-   gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
-      file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
-      0/*strip 16*/, expand_16, do_background, &background, bg);
-}
-
-
-static void
-perform_gamma_composition_tests(png_modifier *pm, int do_background,
-   int expand_16)
-{
-   png_byte colour_type = 0;
-   png_byte bit_depth = 0;
-   int palette_number = 0;
-
-   /* Skip the non-alpha cases - there is no setting of a transparency colour at
-    * present.
-    */
-   while (next_format(&colour_type, &bit_depth, &palette_number))
-      if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0)
-   {
-      unsigned int i, j;
-
-      /* Don't skip the i==j case here - it's relevant. */
-      for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
-      {
-         gamma_composition_test(pm, colour_type, bit_depth, palette_number,
-            pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
-            pm->use_input_precision, do_background, expand_16);
-
-         if (fail(pm))
-            return;
-      }
-   }
-}
-#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
-
-static void
-init_gamma_errors(png_modifier *pm)
-{
-   pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
-   pm->error_color_8 = 0;
-   pm->error_indexed = 0;
-   pm->error_gray_16 = pm->error_color_16 = 0;
-}
-
-static void
-summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth)
-{
-   if (who)
-      printf("Gamma correction with %s:\n", who);
-
-   if (low_bit_depth)
-   {
-      printf("  2 bit gray:  %.5f\n", pm->error_gray_2);
-      printf("  4 bit gray:  %.5f\n", pm->error_gray_4);
-      printf("  8 bit gray:  %.5f\n", pm->error_gray_8);
-      printf("  8 bit color: %.5f\n", pm->error_color_8);
-      printf("  indexed:     %.5f\n", pm->error_indexed);
-   }
-
-#ifdef DO_16BIT
-   printf(" 16 bit gray:  %.5f\n", pm->error_gray_16);
-   printf(" 16 bit color: %.5f\n", pm->error_color_16);
-#endif
-}
-
-static void
-perform_gamma_test(png_modifier *pm, int summary)
-{
-   /*TODO: remove this*/
-   /* Save certain values for the temporary overrides below. */
-   unsigned int calculations_use_input_precision =
-      pm->calculations_use_input_precision;
-   double maxout8 = pm->maxout8;
-
-   /* First some arbitrary no-transform tests: */
-   if (!pm->this.speed && pm->test_gamma_threshold)
-   {
-      perform_gamma_threshold_tests(pm);
-
-      if (fail(pm))
-         return;
-   }
-
-   /* Now some real transforms. */
-   if (pm->test_gamma_transform)
-   {
-      init_gamma_errors(pm);
-      /*TODO: remove this.  Necessary because the current libpng
-       * implementation works in 8 bits:
-       */
-      if (pm->test_gamma_expand16)
-         pm->calculations_use_input_precision = 1;
-      perform_gamma_transform_tests(pm);
-      if (!calculations_use_input_precision)
-         pm->calculations_use_input_precision = 0;
-
-      if (summary)
-      {
-         printf("Gamma correction error summary\n\n");
-         printf("The printed value is the maximum error in the pixel values\n");
-         printf("calculated by the libpng gamma correction code.  The error\n");
-         printf("is calculated as the difference between the output pixel\n");
-         printf("value (always an integer) and the ideal value from the\n");
-         printf("libpng specification (typically not an integer).\n\n");
-
-         printf("Expect this value to be less than .5 for 8 bit formats,\n");
-         printf("less than 1 for formats with fewer than 8 bits and a small\n");
-         printf("number (typically less than 5) for the 16 bit formats.\n");
-         printf("For performance reasons the value for 16 bit formats\n");
-         printf("increases when the image file includes an sBIT chunk.\n\n");
-
-         summarize_gamma_errors(pm, 0/*who*/, 1);
-      }
-   }
-
-   /* The sbit tests produce much larger errors: */
-   if (pm->test_gamma_sbit)
-   {
-      init_gamma_errors(pm);
-      perform_gamma_sbit_tests(pm);
-
-      if (summary)
-         summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U);
-   }
-
-#ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
-   if (pm->test_gamma_scale16)
-   {
-      /* The 16 to 8 bit strip operations: */
-      init_gamma_errors(pm);
-      perform_gamma_scale16_tests(pm);
-
-      if (summary)
-      {
-         printf("Gamma correction with 16 to 8 bit reduction:\n");
-         printf(" 16 bit gray:  %.5f\n", pm->error_gray_16);
-         printf(" 16 bit color: %.5f\n", pm->error_color_16);
-      }
-   }
-#endif
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-   if (pm->test_gamma_background)
-   {
-      init_gamma_errors(pm);
-
-      /*TODO: remove this.  Necessary because the current libpng
-       * implementation works in 8 bits:
-       */
-      if (pm->test_gamma_expand16)
-      {
-         pm->calculations_use_input_precision = 1;
-         pm->maxout8 = .499; /* because the 16 bit background is smashed */
-      }
-      perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
-         pm->test_gamma_expand16);
-      if (!calculations_use_input_precision)
-         pm->calculations_use_input_precision = 0;
-      pm->maxout8 = maxout8;
-
-      if (summary)
-         summarize_gamma_errors(pm, "background", 1);
-   }
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-   if (pm->test_gamma_alpha_mode)
-   {
-      int do_background;
-
-      init_gamma_errors(pm);
-
-      /*TODO: remove this.  Necessary because the current libpng
-       * implementation works in 8 bits:
-       */
-      if (pm->test_gamma_expand16)
-         pm->calculations_use_input_precision = 1;
-      for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
-         do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
-         ++do_background)
-         perform_gamma_composition_tests(pm, do_background,
-            pm->test_gamma_expand16);
-      if (!calculations_use_input_precision)
-         pm->calculations_use_input_precision = 0;
-
-      if (summary)
-         summarize_gamma_errors(pm, "alpha mode", 1);
-   }
-#endif
-}
-#endif /* PNG_READ_GAMMA_SUPPORTED */
-
-/* INTERLACE MACRO VALIDATION */
-/* This is copied verbatim from the specification, it is simply the pass
- * number in which each pixel in each 8x8 tile appears.  The array must
- * be indexed adam7[y][x] and notice that the pass numbers are based at
- * 1, not 0 - the base libpng uses.
- */
-static PNG_CONST
-png_byte adam7[8][8] =
-{
-   { 1,6,4,6,2,6,4,6 },
-   { 7,7,7,7,7,7,7,7 },
-   { 5,6,5,6,5,6,5,6 },
-   { 7,7,7,7,7,7,7,7 },
-   { 3,6,4,6,3,6,4,6 },
-   { 7,7,7,7,7,7,7,7 },
-   { 5,6,5,6,5,6,5,6 },
-   { 7,7,7,7,7,7,7,7 }
-};
-
-/* This routine validates all the interlace support macros in png.h for
- * a variety of valid PNG widths and heights.  It uses a number of similarly
- * named internal routines that feed off the above array.
- */
-static png_uint_32
-png_pass_start_row(int pass)
-{
-   int x, y;
-   ++pass;
-   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
-      return y;
-   return 0xf;
-}
-
-static png_uint_32
-png_pass_start_col(int pass)
-{
-   int x, y;
-   ++pass;
-   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
-      return x;
-   return 0xf;
-}
-
-static int
-png_pass_row_shift(int pass)
-{
-   int x, y, base=(-1), inc=8;
-   ++pass;
-   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
-   {
-      if (base == (-1))
-         base = y;
-      else if (base == y)
-         {}
-      else if (inc == y-base)
-         base=y;
-      else if (inc == 8)
-         inc = y-base, base=y;
-      else if (inc != y-base)
-         return 0xff; /* error - more than one 'inc' value! */
-   }
-
-   if (base == (-1)) return 0xfe; /* error - no row in pass! */
-
-   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
-   switch (inc)
-   {
-case 2: return 1;
-case 4: return 2;
-case 8: return 3;
-default: break;
-   }
-
-   /* error - unrecognized 'inc' */
-   return (inc << 8) + 0xfd;
-}
-
-static int
-png_pass_col_shift(int pass)
-{
-   int x, y, base=(-1), inc=8;
-   ++pass;
-   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
-   {
-      if (base == (-1))
-         base = x;
-      else if (base == x)
-         {}
-      else if (inc == x-base)
-         base=x;
-      else if (inc == 8)
-         inc = x-base, base=x;
-      else if (inc != x-base)
-         return 0xff; /* error - more than one 'inc' value! */
-   }
-
-   if (base == (-1)) return 0xfe; /* error - no row in pass! */
-
-   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
-   switch (inc)
-   {
-case 1: return 0; /* pass 7 has all the columns */
-case 2: return 1;
-case 4: return 2;
-case 8: return 3;
-default: break;
-   }
-
-   /* error - unrecognized 'inc' */
-   return (inc << 8) + 0xfd;
-}
-
-static png_uint_32
-png_row_from_pass_row(png_uint_32 yIn, int pass)
-{
-   /* By examination of the array: */
-   switch (pass)
-   {
-case 0: return yIn * 8;
-case 1: return yIn * 8;
-case 2: return yIn * 8 + 4;
-case 3: return yIn * 4;
-case 4: return yIn * 4 + 2;
-case 5: return yIn * 2;
-case 6: return yIn * 2 + 1;
-default: break;
-   }
-
-   return 0xff; /* bad pass number */
-}
-
-static png_uint_32
-png_col_from_pass_col(png_uint_32 xIn, int pass)
-{
-   /* By examination of the array: */
-   switch (pass)
-   {
-case 0: return xIn * 8;
-case 1: return xIn * 8 + 4;
-case 2: return xIn * 4;
-case 3: return xIn * 4 + 2;
-case 4: return xIn * 2;
-case 5: return xIn * 2 + 1;
-case 6: return xIn;
-default: break;
-   }
-
-   return 0xff; /* bad pass number */
-}
-
-static int
-png_row_in_interlace_pass(png_uint_32 y, int pass)
-{
-   /* Is row 'y' in pass 'pass'? */
-   int x;
-   y &= 7;
-   ++pass;
-   for (x=0; x<8; ++x) if (adam7[y][x] == pass)
-      return 1;
-
-   return 0;
-}
-
-static int
-png_col_in_interlace_pass(png_uint_32 x, int pass)
-{
-   /* Is column 'x' in pass 'pass'? */
-   int y;
-   x &= 7;
-   ++pass;
-   for (y=0; y<8; ++y) if (adam7[y][x] == pass)
-      return 1;
-
-   return 0;
-}
-
-static png_uint_32
-png_pass_rows(png_uint_32 height, int pass)
-{
-   png_uint_32 tiles = height>>3;
-   png_uint_32 rows = 0;
-   unsigned int x, y;
-
-   height &= 7;
-   ++pass;
-   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
-   {
-      rows += tiles;
-      if (y < height) ++rows;
-      break; /* i.e. break the 'x', column, loop. */
-   }
-
-   return rows;
-}
-
-static png_uint_32
-png_pass_cols(png_uint_32 width, int pass)
-{
-   png_uint_32 tiles = width>>3;
-   png_uint_32 cols = 0;
-   unsigned int x, y;
-
-   width &= 7;
-   ++pass;
-   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
-   {
-      cols += tiles;
-      if (x < width) ++cols;
-      break; /* i.e. break the 'y', row, loop. */
-   }
-
-   return cols;
-}
-
-static void
-perform_interlace_macro_validation(void)
-{
-   /* The macros to validate, first those that depend only on pass:
-    *
-    * PNG_PASS_START_ROW(pass)
-    * PNG_PASS_START_COL(pass)
-    * PNG_PASS_ROW_SHIFT(pass)
-    * PNG_PASS_COL_SHIFT(pass)
-    */
-   int pass;
-
-   for (pass=0; pass<7; ++pass)
-   {
-      png_uint_32 m, f, v;
-
-      m = PNG_PASS_START_ROW(pass);
-      f = png_pass_start_row(pass);
-      if (m != f)
-      {
-         fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
-         exit(1);
-      }
-
-      m = PNG_PASS_START_COL(pass);
-      f = png_pass_start_col(pass);
-      if (m != f)
-      {
-         fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
-         exit(1);
-      }
-
-      m = PNG_PASS_ROW_SHIFT(pass);
-      f = png_pass_row_shift(pass);
-      if (m != f)
-      {
-         fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
-         exit(1);
-      }
-
-      m = PNG_PASS_COL_SHIFT(pass);
-      f = png_pass_col_shift(pass);
-      if (m != f)
-      {
-         fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
-         exit(1);
-      }
-
-      /* Macros that depend on the image or sub-image height too:
-       *
-       * PNG_PASS_ROWS(height, pass)
-       * PNG_PASS_COLS(width, pass)
-       * PNG_ROW_FROM_PASS_ROW(yIn, pass)
-       * PNG_COL_FROM_PASS_COL(xIn, pass)
-       * PNG_ROW_IN_INTERLACE_PASS(y, pass)
-       * PNG_COL_IN_INTERLACE_PASS(x, pass)
-       */
-      for (v=0;;)
-      {
-         /* First the base 0 stuff: */
-         m = PNG_ROW_FROM_PASS_ROW(v, pass);
-         f = png_row_from_pass_row(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         m = PNG_COL_FROM_PASS_COL(v, pass);
-         f = png_col_from_pass_col(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
-         f = png_row_in_interlace_pass(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         m = PNG_COL_IN_INTERLACE_PASS(v, pass);
-         f = png_col_in_interlace_pass(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         /* Then the base 1 stuff: */
-         ++v;
-         m = PNG_PASS_ROWS(v, pass);
-         f = png_pass_rows(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         m = PNG_PASS_COLS(v, pass);
-         f = png_pass_cols(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         /* Move to the next v - the stepping algorithm starts skipping
-          * values above 1024.
-          */
-         if (v > 1024)
-         {
-            if (v == PNG_UINT_31_MAX)
-               break;
-
-            v = (v << 1) ^ v;
-            if (v >= PNG_UINT_31_MAX)
-               v = PNG_UINT_31_MAX-1;
-         }
-      }
-   }
-}
-
-/* Test color encodings. These values are back-calculated from the published
- * chromaticities.  The values are accurate to about 14 decimal places; 15 are
- * given.  These values are much more accurate than the ones given in the spec,
- * which typically don't exceed 4 decimal places.  This allows testing of the
- * libpng code to its theoretical accuracy of 4 decimal places.  (If pngvalid
- * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
- * more.)
- *
- * The png_modifier code assumes that encodings[0] is sRGB and treats it
- * specially: do not change the first entry in this list!
- */
-static PNG_CONST color_encoding test_encodings[] =
-{
-/* sRGB: must be first in this list! */
-/*gamma:*/ { 1/2.2,
-/*red:  */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
-/*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
-/*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
-/* Kodak ProPhoto (wide gamut) */
-/*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
-/*red:  */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
-/*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
-/*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
-/* Adobe RGB (1998) */
-/*gamma:*/ { 1/(2+51./256),
-/*red:  */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
-/*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
-/*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
-/* Adobe Wide Gamut RGB */
-/*gamma:*/ { 1/(2+51./256),
-/*red:  */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
-/*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
-/*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
-};
-
-/* signal handler
- *
- * This attempts to trap signals and escape without crashing.  It needs a
- * context pointer so that it can throw an exception (call longjmp) to recover
- * from the condition; this is handled by making the png_modifier used by 'main'
- * into a global variable.
- */
-static png_modifier pm;
-
-static void signal_handler(int signum)
-{
-
-   size_t pos = 0;
-   char msg[64];
-
-   pos = safecat(msg, sizeof msg, pos, "caught signal: ");
-
-   switch (signum)
-   {
-      case SIGABRT:
-         pos = safecat(msg, sizeof msg, pos, "abort");
-         break;
-
-      case SIGFPE:
-         pos = safecat(msg, sizeof msg, pos, "floating point exception");
-         break;
-
-      case SIGILL:
-         pos = safecat(msg, sizeof msg, pos, "illegal instruction");
-         break;
-
-      case SIGINT:
-         pos = safecat(msg, sizeof msg, pos, "interrupt");
-         break;
-
-      case SIGSEGV:
-         pos = safecat(msg, sizeof msg, pos, "invalid memory access");
-         break;
-
-      case SIGTERM:
-         pos = safecat(msg, sizeof msg, pos, "termination request");
-         break;
-
-      default:
-         pos = safecat(msg, sizeof msg, pos, "unknown ");
-         pos = safecatn(msg, sizeof msg, pos, signum);
-         break;
-   }
-
-   store_log(&pm.this, NULL/*png_structp*/, msg, 1/*error*/);
-
-   /* And finally throw an exception so we can keep going, unless this is
-    * SIGTERM in which case stop now.
-    */
-   if (signum != SIGTERM)
-   {
-      struct exception_context *the_exception_context =
-         &pm.this.exception_context;
-
-      Throw &pm.this;
-   }
-
-   else
-      exit(1);
-}
-
-/* main program */
-int main(int argc, PNG_CONST char **argv)
-{
-   volatile int summary = 1;  /* Print the error summary at the end */
-   volatile int memstats = 0; /* Print memory statistics at the end */
-
-   /* Create the given output file on success: */
-   PNG_CONST char *volatile touch = NULL;
-
-   /* This is an array of standard gamma values (believe it or not I've seen
-    * every one of these mentioned somewhere.)
-    *
-    * In the following list the most useful values are first!
-    */
-   static double
-      gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
-
-   /* This records the command and arguments: */
-   size_t cp = 0;
-   char command[1024];
-
-   anon_context(&pm.this);
-
-   /* Add appropriate signal handlers, just the ANSI specified ones: */
-   signal(SIGABRT, signal_handler);
-   signal(SIGFPE, signal_handler);
-   signal(SIGILL, signal_handler);
-   signal(SIGINT, signal_handler);
-   signal(SIGSEGV, signal_handler);
-   signal(SIGTERM, signal_handler);
-
-#ifdef HAVE_FEENABLEEXCEPT
-   /* Only required to enable FP exceptions on platforms where they start off
-    * disabled; this is not necessary but if it is not done pngvalid will likely
-    * end up ignoring FP conditions that other platforms fault.
-    */
-   feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
-#endif
-
-   modifier_init(&pm);
-
-   /* Preallocate the image buffer, because we know how big it needs to be,
-    * note that, for testing purposes, it is deliberately mis-aligned by tag
-    * bytes either side.  All rows have an additional five bytes of padding for
-    * overwrite checking.
-    */
-   store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
-
-   /* Don't give argv[0], it's normally some horrible libtool string: */
-   cp = safecat(command, sizeof command, cp, "pngvalid");
-
-   /* Default to error on warning: */
-   pm.this.treat_warnings_as_errors = 1;
-
-   /* Store the test gammas */
-   pm.gammas = gammas;
-   pm.ngammas = (sizeof gammas) / (sizeof gammas[0]);
-   pm.ngamma_tests = 0; /* default to off */
-
-   /* And the test encodings */
-   pm.encodings = test_encodings;
-   pm.nencodings = (sizeof test_encodings) / (sizeof test_encodings[0]);
-
-   pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
-   /* The following allows results to pass if they correspond to anything in the
-    * transformed range [input-.5,input+.5]; this is is required because of the
-    * way libpng treates the 16_TO_8 flag when building the gamma tables.
-    *
-    * TODO: review this
-    */
-   pm.use_input_precision_16to8 = 1U;
-
-   /* Some default values (set the behavior for 'make check' here).
-    * These values simply control the maximum error permitted in the gamma
-    * transformations.  The practial limits for human perception are described
-    * below (the setting for maxpc16), however for 8 bit encodings it isn't
-    * possible to meet the accepted capabilities of human vision - i.e. 8 bit
-    * images can never be good enough, regardless of encoding.
-    */
-   pm.maxout8 = .1;     /* Arithmetic error in *encoded* value */
-   pm.maxabs8 = .00005; /* 1/20000 */
-   pm.maxcalc8 = .004;  /* +/-1 in 8 bits for compose errors */
-   pm.maxpc8 = .499;    /* I.e., .499% fractional error */
-   pm.maxout16 = .499;  /* Error in *encoded* value */
-   pm.maxabs16 = .00005;/* 1/20000 */
-   pm.maxcalc16 =.000015;/* +/-1 in 16 bits for compose errors */
-
-   /* NOTE: this is a reasonable perceptual limit. We assume that humans can
-    * perceive light level differences of 1% over a 100:1 range, so we need to
-    * maintain 1 in 10000 accuracy (in linear light space), which is what the
-    * following guarantees.  It also allows significantly higher errors at
-    * higher 16 bit values, which is important for performance.  The actual
-    * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
-    * this is only allowed for values >38149 by the following:
-    */
-   pm.maxpc16 = .005;   /* I.e., 1/200% - 1/20000 */
-
-   /* Now parse the command line options. */
-   while (--argc >= 1)
-   {
-      int catmore = 0; /* Set if the argument has an argument. */
-
-      /* Record each argument for posterity: */
-      cp = safecat(command, sizeof command, cp, " ");
-      cp = safecat(command, sizeof command, cp, *++argv);
-
-      if (strcmp(*argv, "-v") == 0)
-         pm.this.verbose = 1;
-
-      else if (strcmp(*argv, "-l") == 0)
-         pm.log = 1;
-
-      else if (strcmp(*argv, "-q") == 0)
-         summary = pm.this.verbose = pm.log = 0;
-
-      else if (strcmp(*argv, "-w") == 0)
-         pm.this.treat_warnings_as_errors = 0;
-
-      else if (strcmp(*argv, "--speed") == 0)
-         pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
-            summary = 0;
-
-      else if (strcmp(*argv, "--memory") == 0)
-         memstats = 1;
-
-      else if (strcmp(*argv, "--size") == 0)
-         pm.test_size = 1;
-
-      else if (strcmp(*argv, "--nosize") == 0)
-         pm.test_size = 0;
-
-      else if (strcmp(*argv, "--standard") == 0)
-         pm.test_standard = 1;
-
-      else if (strcmp(*argv, "--nostandard") == 0)
-         pm.test_standard = 0;
-
-      else if (strcmp(*argv, "--transform") == 0)
-         pm.test_transform = 1;
-
-      else if (strcmp(*argv, "--notransform") == 0)
-         pm.test_transform = 0;
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-      else if (strncmp(*argv, "--transform-disable=",
-         sizeof "--transform-disable") == 0)
-         {
-         pm.test_transform = 1;
-         transform_disable(*argv + sizeof "--transform-disable");
-         }
-
-      else if (strncmp(*argv, "--transform-enable=",
-         sizeof "--transform-enable") == 0)
-         {
-         pm.test_transform = 1;
-         transform_enable(*argv + sizeof "--transform-enable");
-         }
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-      else if (strcmp(*argv, "--gamma") == 0)
-         {
-         /* Just do two gamma tests here (2.2 and linear) for speed: */
-         pm.ngamma_tests = 2U;
-         pm.test_gamma_threshold = 1;
-         pm.test_gamma_transform = 1;
-         pm.test_gamma_sbit = 1;
-         pm.test_gamma_scale16 = 1;
-         pm.test_gamma_background = 1;
-         pm.test_gamma_alpha_mode = 1;
-         }
-
-      else if (strcmp(*argv, "--nogamma") == 0)
-         pm.ngamma_tests = 0;
-
-      else if (strcmp(*argv, "--gamma-threshold") == 0)
-         pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
-
-      else if (strcmp(*argv, "--nogamma-threshold") == 0)
-         pm.test_gamma_threshold = 0;
-
-      else if (strcmp(*argv, "--gamma-transform") == 0)
-         pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
-
-      else if (strcmp(*argv, "--nogamma-transform") == 0)
-         pm.test_gamma_transform = 0;
-
-      else if (strcmp(*argv, "--gamma-sbit") == 0)
-         pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
-
-      else if (strcmp(*argv, "--nogamma-sbit") == 0)
-         pm.test_gamma_sbit = 0;
-
-      else if (strcmp(*argv, "--gamma-16-to-8") == 0)
-         pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
-
-      else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
-         pm.test_gamma_scale16 = 0;
-
-      else if (strcmp(*argv, "--gamma-background") == 0)
-         pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
-
-      else if (strcmp(*argv, "--nogamma-background") == 0)
-         pm.test_gamma_background = 0;
-
-      else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
-         pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
-
-      else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
-         pm.test_gamma_alpha_mode = 0;
-
-      else if (strcmp(*argv, "--expand16") == 0)
-         pm.test_gamma_expand16 = 1;
-
-      else if (strcmp(*argv, "--noexpand16") == 0)
-         pm.test_gamma_expand16 = 0;
-
-      else if (strcmp(*argv, "--more-gammas") == 0)
-         pm.ngamma_tests = 3U;
-
-      else if (strcmp(*argv, "--all-gammas") == 0)
-         pm.ngamma_tests = pm.ngammas;
-
-      else if (strcmp(*argv, "--progressive-read") == 0)
-         pm.this.progressive = 1;
-
-      else if (strcmp(*argv, "--use-update-info") == 0)
-         ++pm.use_update_info; /* Can call multiple times */
-
-      else if (strcmp(*argv, "--interlace") == 0)
-         pm.interlace_type = PNG_INTERLACE_ADAM7;
-
-      else if (strcmp(*argv, "--use-input-precision") == 0)
-         pm.use_input_precision = 1;
-
-      else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
-         pm.calculations_use_input_precision = 1;
-
-      else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
-         pm.assume_16_bit_calculations = 1;
-
-      else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
-         pm.calculations_use_input_precision =
-            pm.assume_16_bit_calculations = 0;
-
-      else if (strcmp(*argv, "--exhaustive") == 0)
-         pm.test_exhaustive = 1;
-
-      else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
-         --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
-
-      else if (argc > 1 && strcmp(*argv, "--touch") == 0)
-         --argc, touch = *++argv, catmore = 1;
-
-      else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
-      {
-         --argc;
-
-         if (strcmp(5+*argv, "abs8") == 0)
-            pm.maxabs8 = atof(*++argv);
-
-         else if (strcmp(5+*argv, "abs16") == 0)
-            pm.maxabs16 = atof(*++argv);
-
-         else if (strcmp(5+*argv, "calc8") == 0)
-            pm.maxcalc8 = atof(*++argv);
-
-         else if (strcmp(5+*argv, "calc16") == 0)
-            pm.maxcalc16 = atof(*++argv);
-
-         else if (strcmp(5+*argv, "out8") == 0)
-            pm.maxout8 = atof(*++argv);
-
-         else if (strcmp(5+*argv, "out16") == 0)
-            pm.maxout16 = atof(*++argv);
-
-         else if (strcmp(5+*argv, "pc8") == 0)
-            pm.maxpc8 = atof(*++argv);
-
-         else if (strcmp(5+*argv, "pc16") == 0)
-            pm.maxpc16 = atof(*++argv);
-
-         else
-         {
-            fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
-            exit(1);
-         }
-
-         catmore = 1;
-      }
-
-      else if (strcmp(*argv, "--log8") == 0)
-         --argc, pm.log8 = atof(*++argv), catmore = 1;
-
-      else if (strcmp(*argv, "--log16") == 0)
-         --argc, pm.log16 = atof(*++argv), catmore = 1;
-
-      else
-      {
-         fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
-         exit(1);
-      }
-
-      if (catmore) /* consumed an extra *argv */
-      {
-         cp = safecat(command, sizeof command, cp, " ");
-         cp = safecat(command, sizeof command, cp, *argv);
-      }
-   }
-
-   /* If pngvalid is run with no arguments default to a reasonable set of the
-    * tests.
-    */
-   if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
-      pm.ngamma_tests == 0)
-   {
-      /* Make this do all the tests done in the test shell scripts with the same
-       * parameters, where possible.  The limitation is that all the progressive
-       * read and interlace stuff has to be done in separate runs, so only the
-       * basic 'standard' and 'size' tests are done.
-       */
-      pm.test_standard = 1;
-      pm.test_size = 1;
-      pm.test_transform = 1;
-      pm.ngamma_tests = 2U;
-   }
-
-   if (pm.ngamma_tests > 0 &&
-      pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
-      pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
-      pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
-   {
-      pm.test_gamma_threshold = 1;
-      pm.test_gamma_transform = 1;
-      pm.test_gamma_sbit = 1;
-      pm.test_gamma_scale16 = 1;
-      pm.test_gamma_background = 1;
-      pm.test_gamma_alpha_mode = 1;
-   }
-
-   else if (pm.ngamma_tests == 0)
-   {
-      /* Nothing to test so turn everything off: */
-      pm.test_gamma_threshold = 0;
-      pm.test_gamma_transform = 0;
-      pm.test_gamma_sbit = 0;
-      pm.test_gamma_scale16 = 0;
-      pm.test_gamma_background = 0;
-      pm.test_gamma_alpha_mode = 0;
-   }
-
-   Try
-   {
-      /* Make useful base images */
-      make_transform_images(&pm.this);
-
-      /* Perform the standard and gamma tests. */
-      if (pm.test_standard)
-      {
-         perform_interlace_macro_validation();
-         perform_formatting_test(&pm.this);
-         perform_standard_test(&pm);
-         perform_error_test(&pm);
-      }
-
-      /* Various oddly sized images: */
-      if (pm.test_size)
-      {
-         make_size_images(&pm.this);
-         perform_size_test(&pm);
-      }
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-      /* Combinatorial transforms: */
-      if (pm.test_transform)
-         perform_transform_test(&pm);
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-      if (pm.ngamma_tests > 0)
-         perform_gamma_test(&pm, summary);
-#endif
-   }
-
-   Catch_anonymous
-   {
-      fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
-      if (!pm.this.verbose)
-      {
-         if (pm.this.error[0] != 0)
-            fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
-
-         fprintf(stderr, "pngvalid: run with -v to see what happened\n");
-      }
-      exit(1);
-   }
-
-   if (summary)
-   {
-      printf("%s: %s (%s point arithmetic)\n",
-         (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
-            pm.this.nwarnings)) ? "FAIL" : "PASS",
-         command,
-#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
-         "floating"
-#else
-         "fixed"
-#endif
-         );
-   }
-
-   if (memstats)
-   {
-      printf("Allocated memory statistics (in bytes):\n"
-         "\tread  %lu maximum single, %lu peak, %lu total\n"
-         "\twrite %lu maximum single, %lu peak, %lu total\n",
-         (unsigned long)pm.this.read_memory_pool.max_max,
-         (unsigned long)pm.this.read_memory_pool.max_limit,
-         (unsigned long)pm.this.read_memory_pool.max_total,
-         (unsigned long)pm.this.write_memory_pool.max_max,
-         (unsigned long)pm.this.write_memory_pool.max_limit,
-         (unsigned long)pm.this.write_memory_pool.max_total);
-   }
-
-   /* Do this here to provoke memory corruption errors in memory not directly
-    * allocated by libpng - not a complete test, but better than nothing.
-    */
-   store_delete(&pm.this);
-
-   /* Error exit if there are any errors, and maybe if there are any
-    * warnings.
-    */
-   if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
-       pm.this.nwarnings))
-   {
-      if (!pm.this.verbose)
-         fprintf(stderr, "pngvalid: %s\n", pm.this.error);
-
-      fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
-          pm.this.nwarnings);
-
-      exit(1);
-   }
-
-   /* Success case. */
-   if (touch != NULL)
-   {
-      FILE *fsuccess = fopen(touch, "wt");
-
-      if (fsuccess != NULL)
-      {
-         int error = 0;
-         fprintf(fsuccess, "PNG validation succeeded\n");
-         fflush(fsuccess);
-         error = ferror(fsuccess);
-
-         if (fclose(fsuccess) || error)
-         {
-            fprintf(stderr, "%s: write failed\n", touch);
-            exit(1);
-         }
-      }
-   }
-
-   return 0;
-}
diff --git a/extern/libpng/include/contrib/pngminim/README b/extern/libpng/include/contrib/pngminim/README
deleted file mode 100644
index 51d5a3c230..0000000000
--- a/extern/libpng/include/contrib/pngminim/README
+++ /dev/null
@@ -1,4 +0,0 @@
-This demonstrates the use of PNG_USER_CONFIG, pngusr.h and pngusr.dfa
-to build minimal decoder, encoder, and progressive reader applications.
-
-See the individual README and pngusr.dfa files for more explanation.
diff --git a/extern/libpng/include/contrib/pngminim/decoder/README b/extern/libpng/include/contrib/pngminim/decoder/README
deleted file mode 100644
index fa979fcb72..0000000000
--- a/extern/libpng/include/contrib/pngminim/decoder/README
+++ /dev/null
@@ -1,10 +0,0 @@
-This demonstrates the use of PNG_USER_CONFIG, pngusr.h and pngusr.dfa
-
-The makefile builds a minimal read-only decoder with embedded libpng
-and zlib.
-
-Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
-on the make command line.
-
-If you prefer to use the shared libraries, go to contrib/pngminus
-and build the png2pnm application there.
diff --git a/extern/libpng/include/contrib/pngminim/decoder/makefile b/extern/libpng/include/contrib/pngminim/decoder/makefile
deleted file mode 100644
index e10e1225d6..0000000000
--- a/extern/libpng/include/contrib/pngminim/decoder/makefile
+++ /dev/null
@@ -1,150 +0,0 @@
-# Makefile for PngMinus (pngm2pnm)
-# Linux / Unix
-
-#CC=cc
-CC=gcc
-LD=$(CC)
-
-# If awk fails try
-# make AWK=nawk
-
-# If cpp fails try
-# make CPP=/lib/cpp
-
-RM=rm -f
-COPY=cp
-
-CFLAGS=-DPNG_USER_CONFIG -DNO_GZCOMPRESS -DNO_GZIP -I. -O1
-
-C=.c
-O=.o
-L=.a
-E=
-
-# Where to find the source code:
-PNGSRC =../../..
-ZLIBSRC=$(PNGSRC)/../zlib
-PROGSRC=$(PNGSRC)/contrib/pngminus
-
-# Zlib (minimal inflate requirements - crc32 is used by libpng)
-# zutil can be eliminated if you provide your own zcalloc and zcfree
-ZSRCS  = adler32$(C) crc32$(C) \
-	 inffast$(C) inflate$(C) inftrees$(C) \
-	 zutil$(C)
-
-# Standard headers
-ZH     = zlib.h crc32.h inffast.h inffixed.h \
-	 inflate.h inftrees.h zutil.h
-
-# Machine generated headers
-ZCONF  = zconf.h
-
-# Headers callers use
-ZINC   = zlib.h $(ZCONF)
-
-# Headers the Zlib source uses
-ZHDRS  = $(ZH) $(ZCONF)
-
-ZOBJS  = adler32$(O) crc32$(O) \
-	 inffast$(O) inflate$(O) inftrees$(O) \
-	 zutil$(O)
-
-# libpng
-PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
-	pngread$(C) pngrio$(C) pngrtran$(C) pngrutil$(C) \
-	pngset$(C) pngtrans$(C)
-	
-# Standard headers
-PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
-
-# Machine generated headers
-PNGCONF=pnglibconf.h
-
-# Headers callers use
-PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
-
-# Headers the PNG library uses
-PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
-
-PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
-	pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) \
-	pngset$(O) pngtrans$(O)
-
-PROGSRCS= pngm2pnm$(C)
-PROGHDRS=
-PROGDOCS=
-PROGOBJS= pngm2pnm$(O)
-
-OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
-
-# implicit make rules -------------------------------------------------------
-
-# note: dependencies do not work on implicit rule lines
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-# dependencies
-
-all: pngm2pnm$(E)
-
-pngm2pnm$(E): $(OBJS)
-	$(LD) -o pngm2pnm$(E) $(OBJS)
-
-# The DFA_XTRA setting turns all libpng options off then
-# turns on those required for this minimal build.
-# The CPP_FLAGS setting causes pngusr.h to be included in
-# both the build of pnglibconf.h and, subsequently, when
-# building libpng itself.
-$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak\
-	$(PNGSRC)/scripts/pnglibconf.dfa \
-	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
-	$(RM) pnglibconf.h pnglibconf.dfn
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
-	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG"\
-	    DFA_XTRA="pngusr.dfa" $@
-
-clean:
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
-	    srcdir=$(PNGSRC) clean
-	$(RM) pngm2pnm$(O)
-	$(RM) pngm2pnm$(E)
-	$(RM) $(OBJS)
-
-# distclean also removes the copied source and headers
-distclean: clean
-	$(RM) -r scripts # historical reasons
-	$(RM) $(PNGSRCS) $(PNGH)
-	$(RM) $(ZSRCS) $(ZH) $(ZCONF)
-	$(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
-
-# Header file dependencies:
-$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
-$(PNGOBJS): $(PNGHDRS) $(ZINC)
-$(ZOBJS): $(ZHDRS)
-
-# Gather the source code from the respective directories
-$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
-	$(RM) $@
-	$(COPY) $(PNGSRC)/$@ $@
-
-# No dependency on the ZLIBSRC target so that it only needs
-# to be specified once.
-$(ZSRCS) $(ZH):
-	$(RM) $@
-	$(COPY) $(ZLIBSRC)/$@ $@
-
-# The unconfigured zconf.h varies in name according to the
-# zlib release
-$(ZCONF):
-	$(RM) $@
-	@for f in zconf.h.in zconf.in.h zconf.h; do\
-	    test -r $(ZLIBSRC)/$$f &&\
-	    echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
-	    $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
-	done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
-
-pngm2pnm.c: $(PROGSRC)/png2pnm.c
-	$(RM) $@
-	$(COPY) $(PROGSRC)/png2pnm.c $@
-
-# End of makefile for pngm2pnm
diff --git a/extern/libpng/include/contrib/pngminim/decoder/pngusr.dfa b/extern/libpng/include/contrib/pngminim/decoder/pngusr.dfa
deleted file mode 100644
index 70d528bc9f..0000000000
--- a/extern/libpng/include/contrib/pngminim/decoder/pngusr.dfa
+++ /dev/null
@@ -1,39 +0,0 @@
-# pngminim/decoder/pngusr.dfa
-#
-# Copyright (c) 2010-2011 Glenn Randers-Pehrson
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# First all the build options off:
-
-everything = off
-
-# All that is required is some read code. This example switches
-# on the sequential read code (see ../preader for a progressive
-# read example).
-
-option SEQUENTIAL_READ on
-
-# You must choose fixed or floating point arithmetic:
-# option FLOATING_POINT on
-
-option FIXED_POINT on
-
-# You must chose the internal fixed point implementation or to
-# use the system floating point.  The latter is considerably
-# smaller (by about 1kbyte on an x86 system):
-# option FLOATING_ARITHMETIC on
-
-option FLOATING_ARITHMETIC off
-
-# Your program will probably need other options.  The example
-# program here, pngm2pnm, requires the following.  Take a look
-# at pnglibconf.h to find out the full set of what has to be
-# enabled to make the following work.
-
-option SETJMP on
-option STDIO on
-option READ_EXPAND on
-option READ_STRIP_16_TO_8 on
diff --git a/extern/libpng/include/contrib/pngminim/decoder/pngusr.h b/extern/libpng/include/contrib/pngminim/decoder/pngusr.h
deleted file mode 100644
index 9d9c50c407..0000000000
--- a/extern/libpng/include/contrib/pngminim/decoder/pngusr.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* minrdpngconf.h: headers to make a minimal png-read-only library
- *
- * Copyright (c) 2007, 2010-2011 Glenn Randers-Pehrson
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
- */
-
-#ifndef MINRDPNGCONF_H
-#define MINRDPNGCONF_H
-
-/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
-
-/* List options to turn off features of the build that do not
- * affect the API (so are not recorded in pnglibconf.h)
- */
-
-#define PNG_NO_WARNINGS
-#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
-
-#endif /* MINRDPNGCONF_H */
diff --git a/extern/libpng/include/contrib/pngminim/encoder/README b/extern/libpng/include/contrib/pngminim/encoder/README
deleted file mode 100644
index ff9aa4597a..0000000000
--- a/extern/libpng/include/contrib/pngminim/encoder/README
+++ /dev/null
@@ -1,10 +0,0 @@
-This demonstrates the use of PNG_USER_CONFIG and pngusr.h
-
-The makefile builds a minimal write-only decoder with embedded libpng
-and zlib.
-
-Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
-on the make command line.
-
-If you prefer to use the shared libraries, go to contrib/pngminus
-and build the pnm2png application there.
diff --git a/extern/libpng/include/contrib/pngminim/encoder/makefile b/extern/libpng/include/contrib/pngminim/encoder/makefile
deleted file mode 100644
index d6f39e2ea0..0000000000
--- a/extern/libpng/include/contrib/pngminim/encoder/makefile
+++ /dev/null
@@ -1,149 +0,0 @@
-# Makefile for PngMinus (pnm2pngm)
-# Linux / Unix
-
-#CC=cc
-CC=gcc
-LD=$(CC)
-
-# If awk fails try
-# make AWK=nawk
-
-# If cpp fails try
-# make CPP=/lib/cpp
-
-RM=rm -f
-COPY=cp
-
-CFLAGS=-DPNG_USER_CONFIG -DNO_GZIP -I. -O1
-
-C=.c
-O=.o
-L=.a
-E=
-
-# Where to find the source code:
-PNGSRC =../../..
-ZLIBSRC=$(PNGSRC)/../zlib
-PROGSRC=$(PNGSRC)/contrib/pngminus
-
-# Zlib
-ZSRCS  = adler32$(C) compress$(C) crc32$(C) deflate$(C) \
-	 trees$(C) zutil$(C)
-
-# Standard headers
-#ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
-ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
-
-# Machine generated headers
-ZCONF  = zconf.h
-
-# Headers callers use
-ZINC   = zlib.h $(ZCONF)
-
-# Headers the Zlib source uses
-ZHDRS  = $(ZH) $(ZCONF)
-
-# compress is not required; it is needed to link the zlib
-# code because deflate defines an unused API function deflateBound
-# which itself calls compressBound from compress.
-ZOBJS  = adler32$(O) compress$(O) crc32$(O) deflate$(O) \
-	 trees$(O) zutil$(O)
-
-# libpng
-PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
-	pngset$(C) pngtrans$(C) pngwio$(C) pngwrite$(C) \
-	pngwtran$(C) pngwutil$(C)
-
-# Standard headers
-PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
-
-# Machine generated headers
-PNGCONF=pnglibconf.h
-
-# Headers callers use
-PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
-
-# Headers the PNG library uses
-PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
-
-PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
-	pngset$(O) pngtrans$(O) pngwio$(O) pngwrite$(O) \
-	pngwtran$(O) pngwutil$(O)
-
-PROGSRCS= pnm2pngm$(C)
-PROGHDRS=
-PROGDOCS=
-PROGOBJS= pnm2pngm$(O)
-
-OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-# dependencies
-
-all: pnm2pngm$(E)
-
-pnm2pngm$(E): $(OBJS)
-	$(LD) -o pnm2pngm$(E) $(OBJS)
-
-# The DFA_XTRA setting turns all libpng options off then
-# turns on those required for this minimal build.
-# The CPP_FLAGS setting causes pngusr.h to be included in
-# both the build of pnglibconf.h and, subsequently, when
-# building libpng itself.
-$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak\
-	$(PNGSRC)/scripts/pnglibconf.dfa \
-	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
-	$(RM) pnglibconf.h pnglibconf.dfn
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
-	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG"\
-	    DFA_XTRA="pngusr.dfa" $@
-
-clean:
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
-	    srcdir=$(PNGSRC) clean
-	$(RM) pnm2pngm$(O)
-	$(RM) pnm2pngm$(E)
-	$(RM) $(OBJS)
-
-# distclean also removes the copied source and headers
-distclean: clean
-	$(RM) -r scripts # historical reasons
-	$(RM) $(PNGSRCS) $(PNGH)
-	$(RM) $(ZSRCS) $(ZH) $(ZCONF)
-	$(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
-
-# Header file dependencies:
-$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
-$(PNGOBJS): $(PNGHDRS) $(ZINC)
-$(ZOBJS): $(ZHDRS)
-
-# Gather the source code from the respective directories
-$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
-	$(RM) $@
-	$(COPY) $(PNGSRC)/$@ $@
-
-# No dependency on the ZLIBSRC target so that it only needs
-# to be specified once.
-$(ZSRCS) $(ZH):
-	$(RM) $@
-	$(COPY) $(ZLIBSRC)/$@ $@
-
-# The unconfigured zconf.h varies in name according to the
-# zlib release
-$(ZCONF):
-	$(RM) $@
-	@for f in zconf.h.in zconf.in.h zconf.h; do\
-	    test -r $(ZLIBSRC)/$$f &&\
-	    echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
-	    $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
-	done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
-
-pnm2pngm.c: $(PROGSRC)/pnm2png.c
-	$(RM) $@
-	$(COPY) $(PROGSRC)/pnm2png.c $@
-
-# End of makefile for pnm2pngm
diff --git a/extern/libpng/include/contrib/pngminim/encoder/pngusr.dfa b/extern/libpng/include/contrib/pngminim/encoder/pngusr.dfa
deleted file mode 100644
index ee88443c9d..0000000000
--- a/extern/libpng/include/contrib/pngminim/encoder/pngusr.dfa
+++ /dev/null
@@ -1,35 +0,0 @@
-# pngminim/encoder/pngusr.dfa
-#
-# Copyright (c) 2010-2011 Glenn Randers-Pehrson
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# First all the build options off:
-
-everything = off
-
-# Switch on the write code - this makes a minimalist encoder
-
-option WRITE on
-
-# You must choose fixed or floating point arithmetic:
-# option FLOATING_POINT on
-
-option FIXED_POINT on
-
-# You must chose the internal fixed point implementation or to
-# use the system floating point.  The latter is considerably
-# smaller (by about 1kbyte on an x86 system):
-# option FLOATING_ARITHMETIC on
-
-option FLOATING_ARITHMETIC off
-
-# Your program will probably need other options.  The example
-# program here, pnm2pngm, requires the following.  Take a look
-# at pnglibconf.h to find out the full set of what has to be
-# enabled to make the following work.
-
-option SETJMP on
-option STDIO on
diff --git a/extern/libpng/include/contrib/pngminim/encoder/pngusr.h b/extern/libpng/include/contrib/pngminim/encoder/pngusr.h
deleted file mode 100644
index 2033aadb20..0000000000
--- a/extern/libpng/include/contrib/pngminim/encoder/pngusr.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* minwrpngconf.h: headers to make a minimal png-write-only library
- *
- * Copyright (c) 2007, 2010-2011 Glenn Randers-Pehrson
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
- */
-
-#ifndef MINWRPNGCONF_H
-#define MINWRPNGCONF_H
-
-/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
-
-/* List options to turn off features of the build that do not
- * affect the API (so are not recorded in pnglibconf.h)
- */
-
-#define PNG_NO_WARNINGS
-#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
-
-#endif /* MINWRPNGCONF_H */
diff --git a/extern/libpng/include/contrib/pngminim/preader/README b/extern/libpng/include/contrib/pngminim/preader/README
deleted file mode 100644
index faa83560a7..0000000000
--- a/extern/libpng/include/contrib/pngminim/preader/README
+++ /dev/null
@@ -1,15 +0,0 @@
-This demonstrates the use of PNG_USER_CONFIG and pngusr.h
-
-The makefile builds a minimal read-only progressive decoder with
-embedded libpng, zlib and your system's X library.
-
-Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
-on the make command line.
-
-Edit makefile if required, to find your X library and include files,
-then
-
-    make ZLIBSRC=directory
-
-If you prefer to use the shared libraries, go to contrib/gregbook
-and build the rpng2-x application there.
diff --git a/extern/libpng/include/contrib/pngminim/preader/makefile b/extern/libpng/include/contrib/pngminim/preader/makefile
deleted file mode 100644
index f4b0ccdc8a..0000000000
--- a/extern/libpng/include/contrib/pngminim/preader/makefile
+++ /dev/null
@@ -1,165 +0,0 @@
-# Makefile for PngMinus (rpng2)
-# Linux / Unix
-
-#CC=cc
-CC=gcc
-LD=$(CC)
-
-# If awk fails try
-# make AWK=nawk
-
-# If cpp fails try
-# make CPP=/lib/cpp
-
-RM=rm -f
-COPY=cp
-
-#XINC = -I/usr/include			# old-style, stock X distributions
-#XLIB = -L/usr/lib/X11 -lX11		#  (including SGI IRIX)
-
-#XINC = -I/usr/openwin/include		# Sun workstations (OpenWindows)
-#XLIB = -L/usr/openwin/lib -lX11
-
-XINC = -I/usr/X11R6/include		# new X distributions (X.org, etc.)
-XLIB = -L/usr/X11R6/lib -lX11
-#XLIB = -L/usr/X11R6/lib64 -lX11	# e.g., Red Hat on AMD64
-
-#XINC = -I/usr/local/include   		# FreeBSD
-#XLIB = -L/usr/local/lib -lX11
-
-#LIBS = $(XLIB)
-LIBS = $(XLIB) -lm                      #platforms that need libm
-
-CFLAGS=-DPNG_USER_CONFIG -DNO_GZCOMPRESS -DNO_GZIP -I. $(XINC) -O1
-
-C=.c
-O=.o
-L=.a
-E=
-
-# Where to find the source code:
-PNGSRC =../../..
-ZLIBSRC=$(PNGSRC)/../zlib
-PROGSRC=$(PNGSRC)/contrib/gregbook
-
-# Zlib (minimal inflate requirements - crc32 is used by libpng)
-# zutil can be eliminated if you provide your own zcalloc and zcfree
-ZSRCS  = adler32$(C) crc32$(C) \
-	 inffast$(C) inflate$(C) inftrees$(C) \
-	 zutil$(C)
-
-# Standard headers
-ZH     = zlib.h crc32.h inffast.h inffixed.h \
-	 inflate.h inftrees.h zutil.h
-
-# Machine generated headers
-ZCONF  = zconf.h
-
-# Headers callers use
-ZINC   = zlib.h $(ZCONF)
-
-# Headers the Zlib source uses
-ZHDRS  = $(ZH) $(ZCONF)
-
-ZOBJS  = adler32$(O) crc32$(O) \
-	 inffast$(O) inflate$(O) inftrees$(O) \
-	 zutil$(O)
-
-# libpng
-PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
-	pngpread$(C) pngread$(C) pngrio$(C) pngrtran$(C) pngrutil$(C) \
-	pngset$(C) pngtrans$(C)
-
-# Standard headers
-PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
-
-# Machine generated headers
-PNGCONF=pnglibconf.h
-
-# Headers callers use
-PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
-
-# Headers the PNG library uses
-PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
-
-PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
-	pngpread$(O) pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) \
-	pngset$(O) pngtrans$(O)
-
-PROGSRCS= rpng2-x$(C) readpng2$(C)
-PROGHDRS= readpng2.h
-PROGDOCS= COPYING LICENSE
-PROGOBJS= rpng2-x$(O) readpng2$(O)
-
-OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-# dependencies
-
-all: $(PROGDOCS) rpng2-x$(E)
-
-rpng2-x$(E): $(OBJS)
-	$(LD) -o rpng2-x$(E) $(OBJS) $(LIBS)
-
-# The DFA_XTRA setting turns all libpng options off then
-# turns on those required for this minimal build.
-# The CPP_FLAGS setting causes pngusr.h to be included in
-# both the build of pnglibconf.h and, subsequently, when
-# building libpng itself.
-$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak\
-	$(PNGSRC)/scripts/pnglibconf.dfa \
-	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
-	$(RM) pnglibconf.h pnglibconf.dfn
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
-	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG"\
-	    DFA_XTRA="pngusr.dfa" $@
-
-clean:
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
-	    srcdir=$(PNGSRC) clean
-	$(RM) rpng2-x$(O)
-	$(RM) rpng2-x$(E)
-	$(RM) $(OBJS)
-
-# distclean also removes the copied source and headers
-distclean: clean
-	$(RM) -r scripts # historical reasons
-	$(RM) $(PNGSRCS) $(PNGH)
-	$(RM) $(ZSRCS) $(ZH) $(ZCONF)
-	$(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
-
-# Header file dependencies:
-$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
-$(PNGOBJS): $(PNGHDRS) $(ZINC)
-$(ZOBJS): $(ZHDRS)
-
-# Gather the source code from the respective directories
-$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
-	$(RM) $@
-	$(COPY) $(PNGSRC)/$@ $@
-
-# No dependency on the ZLIBSRC target so that it only needs
-# to be specified once.
-$(ZSRCS) $(ZH):
-	$(RM) $@
-	$(COPY) $(ZLIBSRC)/$@ $@
-
-# The unconfigured zconf.h varies in name according to the
-# zlib release
-$(ZCONF):
-	$(RM) $@
-	@for f in zconf.h.in zconf.in.h zconf.h; do\
-	    test -r $(ZLIBSRC)/$$f &&\
-	    echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
-	    $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
-	done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
-
-$(PROGSRCS) $(PROGHDRS) $(PROGDOCS): $(PROGSRC)/$@
-	$(RM) $@
-	$(COPY) $(PROGSRC)/$@ $@
-
-# End of makefile for rpng2-x
diff --git a/extern/libpng/include/contrib/pngminim/preader/pngusr.dfa b/extern/libpng/include/contrib/pngminim/preader/pngusr.dfa
deleted file mode 100644
index 216c421ca6..0000000000
--- a/extern/libpng/include/contrib/pngminim/preader/pngusr.dfa
+++ /dev/null
@@ -1,40 +0,0 @@
-# pngminim/preader/pngusr.dfa
-#
-# Copyright (c) 2010-2011 Glenn Randers-Pehrson
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# First all the build options off:
-
-everything = off
-
-# Just switch on the progressive read code
-
-option PROGRESSIVE_READ on
-
-# You may choose fixed or floating point APIs:
-# option FLOATING_POINT on
-
-option FIXED_POINT on
-
-# You must chose the internal fixed point implementation or to
-# use the system floating point.  The latter is considerably
-# smaller (by about 1kbyte on an x86 system):
-
-option FLOATING_ARITHMETIC on
-# option FLOATING_ARITHMETIC off
-
-# Your program will probably need other options.  The example
-# program here, rpng2-x, requires the following.  Take a look
-# at pnglibconf.h to find out the full set of what has to be
-# enabled to make the following work.
-
-option SETJMP on
-option STDIO on
-option READ_bKGD on
-option READ_GAMMA on
-option READ_EXPAND on
-option READ_STRIP_16_TO_8 on
-option READ_GRAY_TO_RGB on
diff --git a/extern/libpng/include/contrib/pngminim/preader/pngusr.h b/extern/libpng/include/contrib/pngminim/preader/pngusr.h
deleted file mode 100644
index 73cfecfbf0..0000000000
--- a/extern/libpng/include/contrib/pngminim/preader/pngusr.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* minrdpngconf.h: headers to make a minimal png-read-only library
- *
- * Copyright (c) 2009, 2010-2011 Glenn Randers-Pehrson
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
- */
-
-#ifndef MINPRDPNGCONF_H
-#define MINPRDPNGCONF_H
-
-/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
-
-/* List options to turn off features of the build that do not
- * affect the API (so are not recorded in pnglibconf.h)
- */
-
-#define PNG_NO_WARNINGS
-#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
-
-#endif /* MINPRDPNGCONF_H */
diff --git a/extern/libpng/include/contrib/pngminus/README b/extern/libpng/include/contrib/pngminus/README
deleted file mode 100644
index bbe7407ecc..0000000000
--- a/extern/libpng/include/contrib/pngminus/README
+++ /dev/null
@@ -1,153 +0,0 @@
-PngMinus
---------
-(copyright Willem van Schaik, 1999)
-
-
-License
--------
-
-Permission to use, copy, modify, and distribute this software and
-its documentation for any purpose and without fee is hereby granted,
-provided that the above copyright notice appear in all copies and
-that both that copyright notice and this permission notice appear in
-supporting documentation. This software is provided "as is" without
-express or implied warranty.
-
-
-Some history
-------------
-Soon after the creation of PNG in 1995, the need was felt for a set of
-pnmtopng / pngtopnm utilities. Independantly Alexander Lehmann and I
-(Willem van Schaik) started such a project. Luckily we discovered this
-and merged the two together into pnmtopng.tar.gz, which is available
-from a/o ftp://ftp.simplesystems.org/pub/libpng/png/.
-
-These two utilities have many, many options and make use of most of the
-features of PNG, like gamma, alpha, sbit, text-chunks, etc. This makes
-the utilities quite complex and by now not anymore very maintainable.
-When we wrote these programs, libpng was still in an early stage.
-Therefore, lots of the functionality that we put in our software can now
-be done using transform-functions in libpng.
-
-Finally, to compile these programs, you need to have installed and
-compiled three libraries: libpng, zlib and netpbm. Especially the latter
-makes the whole setup a bit bulky. But that's unavoidable given the many
-features of pnmtopng.
-
-
-What now
---------
-At this moment libpng is in a very stable state and can do much of the
-work done in pnmtopng. Also, pnmtopng needs to be upgraded to the new
-interface of libpng. Hence, it is time for a rewrite from the ground up
-of pnmtopng and pngtopnm. This will happen in the near future (stay
-tuned). The new package will get a different name to distinguish it from
-the old one: PngPlus.
-
-To experiment a bit with the new interface of libpng, I started off with
-a small prototype that contains only the basic functionality. It doesn't
-have any of the options to read or write special chunks and it will do
-no gamma correction. But this makes it also a simple program that is
-quite easy to understand and can serve well as a template for other
-software developments. (By now there are of course a couple of programs,
-like Greg Roelofs' rpng/wpng, that can be used just as good.)
-
-
-Can and can not
----------------
-As this is the small brother of the future PngPlus, I called this fellow
-PngMinus. Because I started this development in good-old Turbo-C, I
-avoided the use the netpbm library, which requires DOS extenders. Again,
-another reason to call it PngMinus (minus netpbm :-). So, part of the
-program are some elementary routines to read / write pgm- and ppm-files.
-It does not read b&w pbm-files.
-
-The downside of this approach is that you can not use them on images
-that require blocks of memory bigger than 64k (the DOS version). For
-larger images you will get an out-of-memory error.
-
-As said before, PngMinus doesn't correct for gamma. When reading
-png-files you can do this just as well by piping the output of png2pnm
-to pnmgamma, one of the standard PbmPlus tools. This same scenario will
-most probably also be followed in the full-blown future PngPlus, with
-the addition of course of the possibility to create gamma-chunks when
-writing png-files.
-
-On the other hand it supports alpha-channels. When reading a png-image
-you can write the alpha-channel into a pgm-file. And when creating an
-RGB+A png-image, you just combine a ppm-file with a corresponding
-pgm-file containing the alpha-channel. When reading, transparency chunks
-are converted into an alpha-channel and from there on treated the same
-way.
-
-Finally you can opt for writing ascii or binary pgm- and ppm-files. When
-the bit-depth is 16, the format will always be ascii.
-
-
-Using it
---------
-To distinguish them from pnmtopng and PngPlus, the utilities are named
-png2pnm and pnm2png (2 instead of to). The input- and output-files can
-be given as parameters or through redirection. Therefore the programs
-can be part of a pipe.
-
-To list the options type "png2pnm -h" or "pnm2png -h".
-
-
-Just like Scandinavian furniture
---------------------------------
-You have to put it together yourself. I did test the software under
-MS-DOS with Turbo-C 3.0 and under RedHat Linux 4.2 with gcc. In both
-cases I used libpng-1.0.4 and zlib-1.1.3. Later versions should be OK,
-however some older libpng versions have a bug in pngmem.c when using
-Turbo-C 3.0 (see below).
-
-You can build it using one of the two makefiles (make -f makefile.###)
-or use the batch/script files pngminus.bat / pngminus.sh. This assumes
-that you have built the libraries in ../libpng and ../zlib. Using Linux,
-make sure that you have built libpng with makefile.std and not
-makefile.linux (also called .lnx in earlier versions of libpng). The
-latter creates a .so shared-library, while the PngMinus makefile assumes
-a normal .a static library.
-
-If you create a ../pngsuite directory and then store the basn####.png
-files from PngSuite (http://www.schaik.com/pngsuite/) in there, you can
-test in one go the proper functioning of PngMinus, see png2pnm.bat and
-pnm2png.bat (or the .sh versions).
-
-
-Warranty
--------
-Please, remember that this was just a small experiment to learn a few
-things. It will have many unforeseen features <vbg>. Who said bugs? Use
-it when you are in need for something simple or when you want to start
-developing your own stuff.
-
-
-The Turbo bug
--------------
-** pngmem.old
-          hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
-          hptr += 16L;
-** pngmem.c
-          hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
-          hptr = hptr + 16L;
-**
-
-** pngmem.old
-          png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
-          hptr += (png_uint_32)65536L;
-** pngmem.c
-          png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
-          hptr = hptr + 65536L;
-**
-
-
-The end
--------
-Willem van Schaik
-mailto:willem@schaik.com
-http://www.schaik.com/png/
--------
-Oct 1999
-
diff --git a/extern/libpng/include/contrib/pngminus/makefile.std b/extern/libpng/include/contrib/pngminus/makefile.std
deleted file mode 100644
index fa7b5909fc..0000000000
--- a/extern/libpng/include/contrib/pngminus/makefile.std
+++ /dev/null
@@ -1,65 +0,0 @@
-# Makefile for PngMinus (png2pnm and pnm2png)
-# Linux / Unix
-
-#CC=cc
-CC=gcc
-LD=$(CC)
-
-RM=rm -f
-
-#PNGPATH = /usr/local
-#PNGINC = -I$(PNGPATH)/include/libpng15
-#PNGLIB = -L$(PNGPATH)/lib -lpng15
-#PNGLIBS = $(PNGPATH)/lib/libpng15.a
-PNGINC = -I../..
-PNGLIB = -L../.. -lpng
-PNGLIBS = ../../libpng.a
-
-#ZPATH = /usr/local
-#ZINC = -I$(ZPATH)/include
-#ZLIB = -L$(ZPATH)/lib -lz
-#ZLIBS = $(ZPATH)/lib/libz.a
-ZINC = -I../../../zlib
-ZLIB = -L../../../zlib -lz
-ZLIBS = ../../../zlib/libz.a
-
-CFLAGS=$(PNGINC) $(ZINC)
-LDLIBS=$(PNGLIB) $(ZLIB)
-LDLIBSS=$(PNGLIBS) $(ZLIBS)
-C=.c
-O=.o
-L=.a
-E=
-
-# dependencies
-
-#all: png2pnm$(E) pnm2png$(E)
-all: png2pnm$(E) pnm2png$(E) png2pnm-static$(E) pnm2png-static$(E)
-
-png2pnm$(O): png2pnm$(C)
-	$(CC) -c $(CFLAGS) png2pnm$(C)
-
-png2pnm$(E): png2pnm$(O)
-	$(LD) $(LDFLAGS) -o png2pnm$(E) png2pnm$(O) $(LDLIBS) -lm
-
-png2pnm-static$(E): png2pnm$(O)
-	$(LD) $(LDFLAGS) -o png2pnm-static$(E) png2pnm$(O) $(LDLIBSS) -lm
-
-pnm2png$(O): pnm2png$(C)
-	$(CC) -c $(CFLAGS) pnm2png$(C)
-
-pnm2png$(E): pnm2png$(O)
-	$(LD) $(LDFLAGS) -o pnm2png$(E) pnm2png$(O) $(LDLIBS) -lm
-
-pnm2png-static$(E): pnm2png$(O)
-	$(LD) $(LDFLAGS) -o pnm2png-static$(E) pnm2png$(O) $(LDLIBSS) -lm
-
-clean:
-	$(RM) png2pnm$(O)
-	$(RM) pnm2png$(O)
-	$(RM) png2pnm$(E)
-	$(RM) pnm2png$(E)
-	$(RM) png2pnm-static$(E)
-	$(RM) pnm2png-static$(E)
-
-# End of makefile for png2pnm / pnm2png
diff --git a/extern/libpng/include/contrib/pngminus/makefile.tc3 b/extern/libpng/include/contrib/pngminus/makefile.tc3
deleted file mode 100644
index 404f18d5b1..0000000000
--- a/extern/libpng/include/contrib/pngminus/makefile.tc3
+++ /dev/null
@@ -1,38 +0,0 @@
-# Makefile for PngMinus (png2pnm and pnm2png)
-# TurboC++ 3.0
-
-CC=tcc -Ic:\tc3\inc
-LD=tcc -Lc:\tc3\lib
-LB=tlib
-RM=del
-CP=copy
-MODEL=l
-CCFLAGS=-O -m$(MODEL) -I..\libpng -I..\zlib
-LDFLAGS=-m$(MODEL) -L..\libpng -L..\zlib
-C=.c
-O=.obj
-L=.lib
-E=.exe
-
-# dependencies
-
-all: png2pnm$(E) pnm2png$(E)
-
-png2pnm$(O): png2pnm$(C)
-        $(CC) -c $(CCFLAGS) png2pnm$(C)
-
-png2pnm$(E): png2pnm$(O)
-        $(LD) $(LDFLAGS) png2pnm$(O) libpng$(L) zlib$(L)
-
-pnm2png$(O): pnm2png$(C)
-        $(CC) -c $(CCFLAGS) pnm2png$(C)
-
-pnm2png$(E): pnm2png$(O)
-        $(LD) $(LDFLAGS) pnm2png$(O) libpng$(L) zlib$(L)
-
-clean:
-        $(RM) *$(O)
-        $(RM) *$(E)
-
-# End of makefile for png2pnm / pnm2png
-
diff --git a/extern/libpng/include/contrib/pngminus/makevms.com b/extern/libpng/include/contrib/pngminus/makevms.com
deleted file mode 100644
index 00561bcd0d..0000000000
--- a/extern/libpng/include/contrib/pngminus/makevms.com
+++ /dev/null
@@ -1,92 +0,0 @@
-$!------------------------------------------------------------------------------
-$! make Contrib programs of libpng under OpenVMS
-$!
-$!
-$! Look for the compiler used
-$!
-$ zlibsrc = "[---.zlib]"
-$ ccopt="/include=(''zlibsrc',[--])"
-$ if f$getsyi("HW_MODEL").ge.1024
-$ then
-$  ccopt = "/prefix=all"+ccopt
-$  comp  = "__decc__=1"
-$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$ else
-$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
-$   then
-$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
-$     then
-$      comp  = "__gcc__=1"
-$      CC :== GCC
-$     else
-$      comp = "__vaxc__=1"
-$     endif
-$   else
-$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
-$    ccopt = "/decc/prefix=all"+ccopt
-$    comp  = "__decc__=1"
-$  endif
-$ endif
-$ open/write lopt lib.opt
-$ write lopt "[--]libpng.olb/lib"
-$ write lopt "''zlibsrc'libz.olb/lib"
-$ close lopt
-$ open/write xopt x11.opt
-$ write xopt "sys$library:decw$xlibshr.exe/share"
-$ close xopt
-$ write sys$output "Compiling PNG contrib programs ..."
-$   write sys$output "Building pnm2png..."
-$   CALL MAKE pnm2png.OBJ "cc ''CCOPT' pnm2png" -
-	pnm2png.c
-$   call make pnm2png.exe -
-	"LINK pnm2png,lib.opt/opt" -
-	pnm2png.obj
-$   write sys$output "Building png2pnm..."
-$   CALL MAKE png2pnm.OBJ "cc ''CCOPT' png2pnm" -
-	png2pnm.c
-$   call make png2pnm.exe -
-	"LINK png2pnm,lib.opt/opt" -
-	png2pnm.obj
-$ exit
-$!
-$!
-$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
-$ V = 'F$Verify(0)
-$! P1 = What we are trying to make
-$! P2 = Command to make it
-$! P3 - P8  What it depends on
-$
-$ If F$Search(P1) .Eqs. "" Then Goto Makeit
-$ Time = F$CvTime(F$File(P1,"RDT"))
-$arg=3
-$Loop:
-$       Argument = P'arg
-$       If Argument .Eqs. "" Then Goto Exit
-$       El=0
-$Loop2:
-$       File = F$Element(El," ",Argument)
-$       If File .Eqs. " " Then Goto Endl
-$       AFile = ""
-$Loop3:
-$       OFile = AFile
-$       AFile = F$Search(File)
-$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
-$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
-$       Goto Loop3
-$NextEL:
-$       El = El + 1
-$       Goto Loop2
-$EndL:
-$ arg=arg+1
-$ If arg .Le. 8 Then Goto Loop
-$ Goto Exit
-$
-$Makeit:
-$ VV=F$VERIFY(0)
-$ write sys$output P2
-$ 'P2
-$ VV='F$Verify(VV)
-$Exit:
-$ If V Then Set Verify
-$ENDSUBROUTINE
diff --git a/extern/libpng/include/contrib/pngminus/png2pnm.bat b/extern/libpng/include/contrib/pngminus/png2pnm.bat
deleted file mode 100644
index 449cf36750..0000000000
--- a/extern/libpng/include/contrib/pngminus/png2pnm.bat
+++ /dev/null
@@ -1,41 +0,0 @@
-REM -- grayscale
-png2pnm.exe -noraw ..\pngsuite\basn0g01.png basn0g01.pgm
-png2pnm.exe -noraw ..\pngsuite\basn0g02.png basn0g02.pgm
-png2pnm.exe -noraw ..\pngsuite\basn0g04.png basn0g04.pgm
-png2pnm.exe -noraw ..\pngsuite\basn0g08.png basn0g08.pgm
-png2pnm.exe -noraw ..\pngsuite\basn0g16.png basn0g16.pgm
-REM -- full-color
-png2pnm.exe -noraw ..\pngsuite\basn2c08.png basn2c08.ppm
-png2pnm.exe -noraw ..\pngsuite\basn2c16.png basn2c16.ppm
-REM -- palletted
-png2pnm.exe -noraw ..\pngsuite\basn3p01.png basn3p01.ppm
-png2pnm.exe -noraw ..\pngsuite\basn3p02.png basn3p02.ppm
-png2pnm.exe -noraw ..\pngsuite\basn3p04.png basn3p04.ppm
-png2pnm.exe -noraw ..\pngsuite\basn3p08.png basn3p08.ppm
-REM -- gray with alpha-channel
-png2pnm.exe -noraw ..\pngsuite\basn4a08.png basn4a08.pgm
-png2pnm.exe -noraw ..\pngsuite\basn4a16.png basn4a16.pgm
-REM -- color with alpha-channel
-png2pnm.exe -noraw -alpha basn6a08.pgm ..\pngsuite\basn6a08.png basn6a08.ppm
-png2pnm.exe -noraw -alpha basn6a16.pgm ..\pngsuite\basn6a16.png basn6a16.ppm
-REM -- grayscale
-png2pnm.exe -raw ..\pngsuite\basn0g01.png rawn0g01.pgm
-png2pnm.exe -raw ..\pngsuite\basn0g02.png rawn0g02.pgm
-png2pnm.exe -raw ..\pngsuite\basn0g04.png rawn0g04.pgm
-png2pnm.exe -raw ..\pngsuite\basn0g08.png rawn0g08.pgm
-png2pnm.exe -raw ..\pngsuite\basn0g16.png rawn0g16.pgm
-REM -- full-color
-png2pnm.exe -raw ..\pngsuite\basn2c08.png rawn2c08.ppm
-png2pnm.exe -raw ..\pngsuite\basn2c16.png rawn2c16.ppm
-REM -- palletted
-png2pnm.exe -raw ..\pngsuite\basn3p01.png rawn3p01.ppm
-png2pnm.exe -raw ..\pngsuite\basn3p02.png rawn3p02.ppm
-png2pnm.exe -raw ..\pngsuite\basn3p04.png rawn3p04.ppm
-png2pnm.exe -raw ..\pngsuite\basn3p08.png rawn3p08.ppm
-REM -- gray with alpha-channel
-png2pnm.exe -raw ..\pngsuite\basn4a08.png rawn4a08.pgm
-png2pnm.exe -raw ..\pngsuite\basn4a16.png rawn4a16.pgm
-REM -- color with alpha-channel
-png2pnm.exe -noraw -alpha rawn6a08.pgm ..\pngsuite\basn6a08.png rawn6a08.ppm
-png2pnm.exe -noraw -alpha rawn6a16.pgm ..\pngsuite\basn6a16.png rawn6a16.ppm
-
diff --git a/extern/libpng/include/contrib/pngminus/png2pnm.c b/extern/libpng/include/contrib/pngminus/png2pnm.c
deleted file mode 100644
index 2281429435..0000000000
--- a/extern/libpng/include/contrib/pngminus/png2pnm.c
+++ /dev/null
@@ -1,430 +0,0 @@
-/*
- *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
- *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com>
- *
- *  version 1.0 - 1999.10.15 - First version.
- *
- *  Permission to use, copy, modify, and distribute this software and
- *  its documentation for any purpose and without fee is hereby granted,
- *  provided that the above copyright notice appear in all copies and
- *  that both that copyright notice and this permission notice appear in
- *  supporting documentation. This software is provided "as is" without
- *  express or implied warranty.
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#ifdef __TURBOC__
-#include <mem.h>
-#include <fcntl.h>
-#endif
-
-#ifndef BOOL
-#define BOOL unsigned char
-#endif
-#ifndef TRUE
-#define TRUE (BOOL) 1
-#endif
-#ifndef FALSE
-#define FALSE (BOOL) 0
-#endif
-
-#ifdef __TURBOC__
-#define STDIN  0
-#define STDOUT 1
-#define STDERR 2
-#endif
-
-/* to make png2pnm verbose so we can find problems (needs to be before png.h) */
-#ifndef PNG_DEBUG
-#define PNG_DEBUG 0
-#endif
-
-#include "png.h"
-
-/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
-#ifndef png_jmpbuf
-#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
-#endif
-
-/* function prototypes */
-
-int  main (int argc, char *argv[]);
-void usage ();
-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha);
-
-/*
- *  main
- */
-
-int main(int argc, char *argv[])
-{
-  FILE *fp_rd = stdin;
-  FILE *fp_wr = stdout;
-  FILE *fp_al = NULL;
-  BOOL raw = TRUE;
-  BOOL alpha = FALSE;
-  int argi;
-
-  for (argi = 1; argi < argc; argi++)
-  {
-    if (argv[argi][0] == '-')
-    {
-      switch (argv[argi][1])
-      {
-        case 'n':
-          raw = FALSE;
-          break;
-        case 'r':
-          raw = TRUE;
-          break;
-        case 'a':
-          alpha = TRUE;
-          argi++;
-          if ((fp_al = fopen (argv[argi], "wb")) == NULL)
-          {
-            fprintf (stderr, "PNM2PNG\n");
-            fprintf (stderr, "Error:  can not create alpha-channel file %s\n", argv[argi]);
-            exit (1);
-          }
-          break;
-        case 'h':
-        case '?':
-          usage();
-          exit(0);
-          break;
-        default:
-          fprintf (stderr, "PNG2PNM\n");
-          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
-          usage();
-          exit(1);
-          break;
-      } /* end switch */
-    }
-    else if (fp_rd == stdin)
-    {
-      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
-      {
-             fprintf (stderr, "PNG2PNM\n");
-            fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
-            exit (1);
-      }
-    }
-    else if (fp_wr == stdout)
-    {
-      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
-      {
-        fprintf (stderr, "PNG2PNM\n");
-        fprintf (stderr, "Error:  can not create file %s\n", argv[argi]);
-        exit (1);
-      }
-    }
-    else
-    {
-      fprintf (stderr, "PNG2PNM\n");
-      fprintf (stderr, "Error:  too many parameters\n");
-      usage();
-      exit(1);
-    }
-  } /* end for */
-
-#ifdef __TURBOC__
-  /* set stdin/stdout if required to binary */
-  if (fp_rd == stdin)
-  {
-    setmode (STDIN, O_BINARY);
-  }
-  if ((raw) && (fp_wr == stdout))
-  {
-    setmode (STDOUT, O_BINARY);
-  }
-#endif
-
-  /* call the conversion program itself */
-  if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE)
-  {
-    fprintf (stderr, "PNG2PNM\n");
-    fprintf (stderr, "Error:  unsuccessful conversion of PNG-image\n");
-    exit(1);
-  }
-
-  /* close input file */
-  fclose (fp_rd);
-  /* close output file */
-  fclose (fp_wr);
-  /* close alpha file */
-  if (alpha)
-    fclose (fp_al);
-
-  return 0;
-}
-
-/*
- *  usage
- */
-
-void usage()
-{
-  fprintf (stderr, "PNG2PNM\n");
-  fprintf (stderr, "   by Willem van Schaik, 1999\n");
-#ifdef __TURBOC__
-  fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");
-#else
-  fprintf (stderr, "   for Linux (and Unix) compilers\n");
-#endif
-  fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
-  fprintf (stderr, "   or:  ... | png2pnm [options]\n");
-  fprintf (stderr, "Options:\n");
-  fprintf (stderr, "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
-  fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
-  fprintf (stderr, "   -h | -?  print this help-information\n");
-}
-
-/*
- *  png2pnm
- */
-
-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha)
-{
-  png_struct    *png_ptr = NULL;
-  png_info        *info_ptr = NULL;
-  png_byte      buf[8];
-  png_byte      *png_pixels = NULL;
-  png_byte      **row_pointers = NULL;
-  png_byte      *pix_ptr = NULL;
-  png_uint_32   row_bytes;
-
-  png_uint_32   width;
-  png_uint_32   height;
-  int           bit_depth;
-  int           channels;
-  int           color_type;
-  int           alpha_present;
-  int           row, col;
-  int           ret;
-  int           i;
-  long          dep_16;
-
-  /* read and check signature in PNG file */
-  ret = fread (buf, 1, 8, png_file);
-  if (ret != 8)
-    return FALSE;
-
-  ret = png_sig_cmp (buf, 0, 8);
-  if (ret)
-    return FALSE;
-
-  /* create png and info structures */
-
-  png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING,
-    NULL, NULL, NULL);
-  if (!png_ptr)
-    return FALSE;   /* out of memory */
-
-  info_ptr = png_create_info_struct (png_ptr);
-  if (!info_ptr)
-  {
-    png_destroy_read_struct (&png_ptr, NULL, NULL);
-    return FALSE;   /* out of memory */
-  }
-
-  if (setjmp (png_jmpbuf(png_ptr)))
-  {
-    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
-    return FALSE;
-  }
-
-  /* set up the input control for C streams */
-  png_init_io (png_ptr, png_file);
-  png_set_sig_bytes (png_ptr, 8);  /* we already read the 8 signature bytes */
-
-  /* read the file information */
-  png_read_info (png_ptr, info_ptr);
-
-  /* get size and bit-depth of the PNG-image */
-  png_get_IHDR (png_ptr, info_ptr,
-    &width, &height, &bit_depth, &color_type,
-    NULL, NULL, NULL);
-
-  /* set-up the transformations */
-
-  /* transform paletted images into full-color rgb */
-  if (color_type == PNG_COLOR_TYPE_PALETTE)
-    png_set_expand (png_ptr);
-  /* expand images to bit-depth 8 (only applicable for grayscale images) */
-  if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
-    png_set_expand (png_ptr);
-  /* transform transparency maps into full alpha-channel */
-  if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
-    png_set_expand (png_ptr);
-
-#ifdef NJET
-  /* downgrade 16-bit images to 8 bit */
-  if (bit_depth == 16)
-    png_set_strip_16 (png_ptr);
-  /* transform grayscale images into full-color */
-  if (color_type == PNG_COLOR_TYPE_GRAY ||
-    color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-    png_set_gray_to_rgb (png_ptr);
-  /* only if file has a file gamma, we do a correction */
-  if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))
-    png_set_gamma (png_ptr, (double) 2.2, file_gamma);
-#endif
-
-  /* all transformations have been registered; now update info_ptr data,
-   * get rowbytes and channels, and allocate image memory */
-
-  png_read_update_info (png_ptr, info_ptr);
-
-  /* get the new color-type and bit-depth (after expansion/stripping) */
-  png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
-    NULL, NULL, NULL);
-
-  /* check for 16-bit files */
-  if (bit_depth == 16)
-  {
-    raw = FALSE;
-#ifdef __TURBOC__
-    pnm_file->flags &= ~((unsigned) _F_BIN);
-#endif
-  }
-
-  /* calculate new number of channels and store alpha-presence */
-  if (color_type == PNG_COLOR_TYPE_GRAY)
-    channels = 1;
-  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-    channels = 2;
-  else if (color_type == PNG_COLOR_TYPE_RGB)
-    channels = 3;
-  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-    channels = 4;
-  else
-    channels = 0; /* should never happen */
-  alpha_present = (channels - 1) % 2;
-
-  /* check if alpha is expected to be present in file */
-  if (alpha && !alpha_present)
-  {
-    fprintf (stderr, "PNG2PNM\n");
-    fprintf (stderr, "Error:  PNG-file doesn't contain alpha channel\n");
-    exit (1);
-  }
-
-  /* row_bytes is the width x number of channels x (bit-depth / 8) */
-  row_bytes = png_get_rowbytes (png_ptr, info_ptr);
-
-  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
-    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
-    return FALSE;
-  }
-
-  if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
-  {
-    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
-    free (png_pixels);
-    png_pixels = NULL;
-    return FALSE;
-  }
-
-  /* set the individual row_pointers to point at the correct offsets */
-  for (i = 0; i < (height); i++)
-    row_pointers[i] = png_pixels + i * row_bytes;
-
-  /* now we can go ahead and just read the whole image */
-  png_read_image (png_ptr, row_pointers);
-
-  /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
-  png_read_end (png_ptr, info_ptr);
-
-  /* clean up after the read, and free any memory allocated - REQUIRED */
-  png_destroy_read_struct (&png_ptr, &info_ptr, (png_infopp) NULL);
-
-  /* write header of PNM file */
-
-  if ((color_type == PNG_COLOR_TYPE_GRAY) ||
-      (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
-  {
-    fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2");
-    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
-    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
-  }
-  else if ((color_type == PNG_COLOR_TYPE_RGB) ||
-           (color_type == PNG_COLOR_TYPE_RGB_ALPHA))
-  {
-    fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3");
-    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
-    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
-  }
-
-  /* write header of PGM file with alpha channel */
-
-  if ((alpha) &&
-      ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||
-       (color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
-  {
-    fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2");
-    fprintf (alpha_file, "%d %d\n", (int) width, (int) height);
-    fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
-  }
-
-  /* write data to PNM file */
-  pix_ptr = png_pixels;
-
-  for (row = 0; row < height; row++)
-  {
-    for (col = 0; col < width; col++)
-    {
-      for (i = 0; i < (channels - alpha_present); i++)
-      {
-        if (raw)
-          fputc ((int) *pix_ptr++ , pnm_file);
-        else
-          if (bit_depth == 16){
-            dep_16 = (long) *pix_ptr++;
-            fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++));
-          }
-          else
-            fprintf (pnm_file, "%ld ", (long) *pix_ptr++);
-      }
-      if (alpha_present)
-      {
-        if (!alpha)
-        {
-          pix_ptr++; /* alpha */
-          if (bit_depth == 16)
-            pix_ptr++;
-        }
-        else /* output alpha-channel as pgm file */
-        {
-          if (raw)
-            fputc ((int) *pix_ptr++ , alpha_file);
-          else
-            if (bit_depth == 16){
-              dep_16 = (long) *pix_ptr++;
-              fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);
-            }
-            else
-              fprintf (alpha_file, "%ld ", (long) *pix_ptr++);
-        }
-      } /* if alpha_present */
-
-      if (!raw)
-        if (col % 4 == 3)
-          fprintf (pnm_file, "\n");
-    } /* end for col */
-
-    if (!raw)
-      if (col % 4 != 0)
-        fprintf (pnm_file, "\n");
-  } /* end for row */
-
-  if (row_pointers != (unsigned char**) NULL)
-    free (row_pointers);
-  if (png_pixels != (unsigned char*) NULL)
-    free (png_pixels);
-
-  return TRUE;
-
-} /* end of source */
-
diff --git a/extern/libpng/include/contrib/pngminus/png2pnm.sh b/extern/libpng/include/contrib/pngminus/png2pnm.sh
deleted file mode 100644
index b1c05370df..0000000000
--- a/extern/libpng/include/contrib/pngminus/png2pnm.sh
+++ /dev/null
@@ -1,42 +0,0 @@
-#!/bin/sh
-# -- grayscale
-./png2pnm -noraw ../pngsuite/basn0g01.png basn0g01.pgm
-./png2pnm -noraw ../pngsuite/basn0g02.png basn0g02.pgm
-./png2pnm -noraw ../pngsuite/basn0g04.png basn0g04.pgm
-./png2pnm -noraw ../pngsuite/basn0g08.png basn0g08.pgm
-./png2pnm -noraw ../pngsuite/basn0g16.png basn0g16.pgm
-# -- full-color
-./png2pnm -noraw ../pngsuite/basn2c08.png basn2c08.ppm
-./png2pnm -noraw ../pngsuite/basn2c16.png basn2c16.ppm
-# -- palletted
-./png2pnm -noraw ../pngsuite/basn3p01.png basn3p01.ppm
-./png2pnm -noraw ../pngsuite/basn3p02.png basn3p02.ppm
-./png2pnm -noraw ../pngsuite/basn3p04.png basn3p04.ppm
-./png2pnm -noraw ../pngsuite/basn3p08.png basn3p08.ppm
-# -- gray with alpha-channel
-./png2pnm -noraw ../pngsuite/basn4a08.png basn4a08.pgm
-./png2pnm -noraw ../pngsuite/basn4a16.png basn4a16.pgm
-# -- color with alpha-channel
-./png2pnm -noraw -alpha basn6a08.pgm ../pngsuite/basn6a08.png basn6a08.ppm
-./png2pnm -noraw -alpha basn6a16.pgm ../pngsuite/basn6a16.png basn6a16.ppm
-# -- grayscale
-./png2pnm -raw ../pngsuite/basn0g01.png rawn0g01.pgm
-./png2pnm -raw ../pngsuite/basn0g02.png rawn0g02.pgm
-./png2pnm -raw ../pngsuite/basn0g04.png rawn0g04.pgm
-./png2pnm -raw ../pngsuite/basn0g08.png rawn0g08.pgm
-./png2pnm -raw ../pngsuite/basn0g16.png rawn0g16.pgm
-# -- full-color
-./png2pnm -raw ../pngsuite/basn2c08.png rawn2c08.ppm
-./png2pnm -raw ../pngsuite/basn2c16.png rawn2c16.ppm
-# -- palletted
-./png2pnm -raw ../pngsuite/basn3p01.png rawn3p01.ppm
-./png2pnm -raw ../pngsuite/basn3p02.png rawn3p02.ppm
-./png2pnm -raw ../pngsuite/basn3p04.png rawn3p04.ppm
-./png2pnm -raw ../pngsuite/basn3p08.png rawn3p08.ppm
-# -- gray with alpha-channel
-./png2pnm -raw ../pngsuite/basn4a08.png rawn4a08.pgm
-./png2pnm -raw ../pngsuite/basn4a16.png rawn4a16.pgm
-# -- color with alpha-channel
-./png2pnm -noraw -alpha rawn6a08.pgm ../pngsuite/basn6a08.png rawn6a08.ppm
-./png2pnm -noraw -alpha rawn6a16.pgm ../pngsuite/basn6a16.png rawn6a16.ppm
-
diff --git a/extern/libpng/include/contrib/pngminus/pngminus.bat b/extern/libpng/include/contrib/pngminus/pngminus.bat
deleted file mode 100644
index 911bb8dff9..0000000000
--- a/extern/libpng/include/contrib/pngminus/pngminus.bat
+++ /dev/null
@@ -1,4 +0,0 @@
-make -f makefile.tc3
-call png2pnm.bat
-call pnm2png.bat
-
diff --git a/extern/libpng/include/contrib/pngminus/pngminus.sh b/extern/libpng/include/contrib/pngminus/pngminus.sh
deleted file mode 100644
index 2a0a9d8fbb..0000000000
--- a/extern/libpng/include/contrib/pngminus/pngminus.sh
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/bin/sh
-make -f makefile.std
-sh png2pnm.sh
-sh pnm2png.sh
-
diff --git a/extern/libpng/include/contrib/pngminus/pnm2png.bat b/extern/libpng/include/contrib/pngminus/pnm2png.bat
deleted file mode 100644
index f756cb84de..0000000000
--- a/extern/libpng/include/contrib/pngminus/pnm2png.bat
+++ /dev/null
@@ -1,41 +0,0 @@
-REM -- grayscale
-pnm2png.exe basn0g01.pgm basn0g01.png
-pnm2png.exe basn0g02.pgm basn0g02.png
-pnm2png.exe basn0g04.pgm basn0g04.png
-pnm2png.exe basn0g08.pgm basn0g08.png
-pnm2png.exe basn0g16.pgm basn0g16.png
-REM -- full-color
-pnm2png.exe basn2c08.ppm basn2c08.png
-pnm2png.exe basn2c16.ppm basn2c16.png
-REM -- palletted
-pnm2png.exe basn3p01.ppm basn3p01.png
-pnm2png.exe basn3p02.ppm basn3p02.png
-pnm2png.exe basn3p04.ppm basn3p04.png
-pnm2png.exe basn3p08.ppm basn3p08.png
-REM -- gray with alpha-channel
-pnm2png.exe -alpha basn6a08.pgm basn4a08.pgm basn4a08.png
-pnm2png.exe -alpha basn6a16.pgm basn4a16.pgm basn4a16.png
-REM -- color with alpha-channel
-pnm2png.exe -alpha basn6a08.pgm basn6a08.ppm basn6a08.png
-pnm2png.exe -alpha basn6a16.pgm basn6a16.ppm basn6a16.png
-REM -- grayscale
-pnm2png.exe rawn0g01.pgm rawn0g01.png
-pnm2png.exe rawn0g02.pgm rawn0g02.png
-pnm2png.exe rawn0g04.pgm rawn0g04.png
-pnm2png.exe rawn0g08.pgm rawn0g08.png
-pnm2png.exe rawn0g16.pgm rawn0g16.png
-REM -- full-color
-pnm2png.exe rawn2c08.ppm rawn2c08.png
-pnm2png.exe rawn2c16.ppm rawn2c16.png
-REM -- palletted
-pnm2png.exe rawn3p01.ppm rawn3p01.png
-pnm2png.exe rawn3p02.ppm rawn3p02.png
-pnm2png.exe rawn3p04.ppm rawn3p04.png
-pnm2png.exe rawn3p08.ppm rawn3p08.png
-REM -- gray with alpha-channel
-pnm2png.exe -alpha rawn6a08.pgm rawn4a08.pgm rawn4a08.png
-pnm2png.exe -alpha rawn6a16.pgm rawn4a16.pgm rawn4a16.png
-REM -- color with alpha-channel
-pnm2png.exe -alpha rawn6a08.pgm rawn6a08.ppm rawn6a08.png
-pnm2png.exe -alpha rawn6a16.pgm rawn6a16.ppm rawn6a16.png
-
diff --git a/extern/libpng/include/contrib/pngminus/pnm2png.c b/extern/libpng/include/contrib/pngminus/pnm2png.c
deleted file mode 100644
index 4cdfad8313..0000000000
--- a/extern/libpng/include/contrib/pngminus/pnm2png.c
+++ /dev/null
@@ -1,533 +0,0 @@
-/*
- *  pnm2png.c --- conversion from PBM/PGM/PPM-file to PNG-file
- *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com>
- *
- *  version 1.0 - 1999.10.15 - First version.
- *
- *  Permission to use, copy, modify, and distribute this software and
- *  its documentation for any purpose and without fee is hereby granted,
- *  provided that the above copyright notice appear in all copies and
- *  that both that copyright notice and this permission notice appear in
- *  supporting documentation. This software is provided "as is" without
- *  express or implied warranty.
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#ifdef __TURBOC__
-#include <mem.h>
-#include <fcntl.h>
-#endif
-
-#ifndef BOOL
-#define BOOL unsigned char
-#endif
-#ifndef TRUE
-#define TRUE (BOOL) 1
-#endif
-#ifndef FALSE
-#define FALSE (BOOL) 0
-#endif
-
-#define STDIN  0
-#define STDOUT 1
-#define STDERR 2
-
-/* to make pnm2png verbose so we can find problems (needs to be before png.h) */
-#ifndef PNG_DEBUG
-#define PNG_DEBUG 0
-#endif
-
-#include "png.h"
-
-/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
-#ifndef png_jmpbuf
-#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
-#endif
-
-/* function prototypes */
-
-int  main (int argc, char *argv[]);
-void usage ();
-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha);
-void get_token(FILE *pnm_file, char *token);
-png_uint_32 get_data (FILE *pnm_file, int depth);
-png_uint_32 get_value (FILE *pnm_file, int depth);
-
-/*
- *  main
- */
-
-int main(int argc, char *argv[])
-{
-  FILE *fp_rd = stdin;
-  FILE *fp_al = NULL;
-  FILE *fp_wr = stdout;
-  BOOL interlace = FALSE;
-  BOOL alpha = FALSE;
-  int argi;
-
-  for (argi = 1; argi < argc; argi++)
-  {
-    if (argv[argi][0] == '-')
-    {
-      switch (argv[argi][1])
-      {
-        case 'i':
-          interlace = TRUE;
-          break;
-        case 'a':
-          alpha = TRUE;
-          argi++;
-          if ((fp_al = fopen (argv[argi], "rb")) == NULL)
-          {
-            fprintf (stderr, "PNM2PNG\n");
-            fprintf (stderr, "Error:  alpha-channel file %s does not exist\n",
-               argv[argi]);
-            exit (1);
-          }
-          break;
-        case 'h':
-        case '?':
-          usage();
-          exit(0);
-          break;
-        default:
-          fprintf (stderr, "PNM2PNG\n");
-          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
-          usage();
-          exit(1);
-          break;
-      } /* end switch */
-    }
-    else if (fp_rd == stdin)
-    {
-      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
-      {
-        fprintf (stderr, "PNM2PNG\n");
-        fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
-        exit (1);
-      }
-    }
-    else if (fp_wr == stdout)
-    {
-      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
-      {
-        fprintf (stderr, "PNM2PNG\n");
-        fprintf (stderr, "Error:  can not create PNG-file %s\n", argv[argi]);
-        exit (1);
-      }
-    }
-    else
-    {
-      fprintf (stderr, "PNM2PNG\n");
-      fprintf (stderr, "Error:  too many parameters\n");
-      usage();
-      exit (1);
-    }
-  } /* end for */
-
-#ifdef __TURBOC__
-  /* set stdin/stdout to binary, we're reading the PNM always! in binary format */
-  if (fp_rd == stdin)
-  {
-    setmode (STDIN, O_BINARY);
-  }
-  if (fp_wr == stdout)
-  {
-    setmode (STDOUT, O_BINARY);
-  }
-#endif
-
-  /* call the conversion program itself */
-  if (pnm2png (fp_rd, fp_wr, fp_al, interlace, alpha) == FALSE)
-  {
-    fprintf (stderr, "PNM2PNG\n");
-    fprintf (stderr, "Error:  unsuccessful converting to PNG-image\n");
-    exit (1);
-  }
-
-  /* close input file */
-  fclose (fp_rd);
-  /* close output file */
-  fclose (fp_wr);
-  /* close alpha file */
-  if (alpha)
-    fclose (fp_al);
-
-  return 0;
-}
-
-/*
- *  usage
- */
-
-void usage()
-{
-  fprintf (stderr, "PNM2PNG\n");
-  fprintf (stderr, "   by Willem van Schaik, 1999\n");
-#ifdef __TURBOC__
-  fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");
-#else
-  fprintf (stderr, "   for Linux (and Unix) compilers\n");
-#endif
-  fprintf (stderr, "Usage:  pnm2png [options] <file>.<pnm> [<file>.png]\n");
-  fprintf (stderr, "   or:  ... | pnm2png [options]\n");
-  fprintf (stderr, "Options:\n");
-  fprintf (stderr, "   -i[nterlace]   write png-file with interlacing on\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
-  fprintf (stderr, "   -h | -?  print this help-information\n");
-}
-
-/*
- *  pnm2png
- */
-
-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha)
-{
-  png_struct    *png_ptr = NULL;
-  png_info      *info_ptr = NULL;
-  png_byte      *png_pixels = NULL;
-  png_byte      **row_pointers = NULL;
-  png_byte      *pix_ptr = NULL;
-  png_uint_32   row_bytes;
-
-  char          type_token[16];
-  char          width_token[16];
-  char          height_token[16];
-  char          maxval_token[16];
-  int           color_type;
-  png_uint_32   width, alpha_width;
-  png_uint_32   height, alpha_height;
-  png_uint_32   maxval;
-  int           bit_depth = 0;
-  int           channels;
-  int           alpha_depth = 0;
-  int           alpha_present;
-  int           row, col;
-  BOOL          raw, alpha_raw = FALSE;
-  png_uint_32   tmp16;
-  int           i;
-
-  /* read header of PNM file */
-
-  get_token(pnm_file, type_token);
-  if (type_token[0] != 'P')
-  {
-    return FALSE;
-  }
-  else if ((type_token[1] == '1') || (type_token[1] == '4'))
-  {
-    raw = (type_token[1] == '4');
-    color_type = PNG_COLOR_TYPE_GRAY;
-    bit_depth = 1;
-  }
-  else if ((type_token[1] == '2') || (type_token[1] == '5'))
-  {
-    raw = (type_token[1] == '5');
-    color_type = PNG_COLOR_TYPE_GRAY;
-    get_token(pnm_file, width_token);
-    sscanf (width_token, "%lu", &width);
-    get_token(pnm_file, height_token);
-    sscanf (height_token, "%lu", &height);
-    get_token(pnm_file, maxval_token);
-    sscanf (maxval_token, "%lu", &maxval);
-    if (maxval <= 1)
-      bit_depth = 1;
-    else if (maxval <= 3)
-      bit_depth = 2;
-    else if (maxval <= 15)
-      bit_depth = 4;
-    else if (maxval <= 255)
-      bit_depth = 8;
-    else /* if (maxval <= 65535) */
-      bit_depth = 16;
-  }
-  else if ((type_token[1] == '3') || (type_token[1] == '6'))
-  {
-    raw = (type_token[1] == '6');
-    color_type = PNG_COLOR_TYPE_RGB;
-    get_token(pnm_file, width_token);
-    sscanf (width_token, "%lu", &width);
-    get_token(pnm_file, height_token);
-    sscanf (height_token, "%lu", &height);
-    get_token(pnm_file, maxval_token);
-    sscanf (maxval_token, "%lu", &maxval);
-    if (maxval <= 1)
-      bit_depth = 1;
-    else if (maxval <= 3)
-      bit_depth = 2;
-    else if (maxval <= 15)
-      bit_depth = 4;
-    else if (maxval <= 255)
-      bit_depth = 8;
-    else /* if (maxval <= 65535) */
-      bit_depth = 16;
-  }
-  else
-  {
-    return FALSE;
-  }
-
-  /* read header of PGM file with alpha channel */
-
-  if (alpha)
-  {
-    if (color_type == PNG_COLOR_TYPE_GRAY)
-      color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
-    if (color_type == PNG_COLOR_TYPE_RGB)
-      color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-
-    get_token(alpha_file, type_token);
-    if (type_token[0] != 'P')
-    {
-      return FALSE;
-    }
-    else if ((type_token[1] == '2') || (type_token[1] == '5'))
-    {
-      alpha_raw = (type_token[1] == '5');
-      get_token(alpha_file, width_token);
-      sscanf (width_token, "%lu", &alpha_width);
-      if (alpha_width != width)
-        return FALSE;
-      get_token(alpha_file, height_token);
-      sscanf (height_token, "%lu", &alpha_height);
-      if (alpha_height != height)
-        return FALSE;
-      get_token(alpha_file, maxval_token);
-      sscanf (maxval_token, "%lu", &maxval);
-      if (maxval <= 1)
-        alpha_depth = 1;
-      else if (maxval <= 3)
-        alpha_depth = 2;
-      else if (maxval <= 15)
-        alpha_depth = 4;
-      else if (maxval <= 255)
-        alpha_depth = 8;
-      else /* if (maxval <= 65535) */
-        alpha_depth = 16;
-      if (alpha_depth != bit_depth)
-        return FALSE;
-    }
-    else
-    {
-      return FALSE;
-    }
-  } /* end if alpha */
-
-  /* calculate the number of channels and store alpha-presence */
-  if (color_type == PNG_COLOR_TYPE_GRAY)
-    channels = 1;
-  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-    channels = 2;
-  else if (color_type == PNG_COLOR_TYPE_RGB)
-    channels = 3;
-  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-    channels = 4;
-  else
-    channels = 0; /* should not happen */
-
-  alpha_present = (channels - 1) % 2;
-
-  /* row_bytes is the width x number of channels x (bit-depth / 8) */
-  row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);
-
-  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL)
-    return FALSE;
-
-  /* read data from PNM file */
-  pix_ptr = png_pixels;
-
-  for (row = 0; row < height; row++)
-  {
-    for (col = 0; col < width; col++)
-    {
-      for (i = 0; i < (channels - alpha_present); i++)
-      {
-        if (raw)
-          *pix_ptr++ = get_data (pnm_file, bit_depth);
-        else
-          if (bit_depth <= 8)
-            *pix_ptr++ = get_value (pnm_file, bit_depth);
-          else
-          {
-            tmp16 = get_value (pnm_file, bit_depth);
-            *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
-            pix_ptr++;
-            *pix_ptr = (png_byte) (tmp16 & 0xFF);
-            pix_ptr++;
-          }
-      }
-
-      if (alpha) /* read alpha-channel from pgm file */
-      {
-        if (alpha_raw)
-          *pix_ptr++ = get_data (alpha_file, alpha_depth);
-        else
-          if (alpha_depth <= 8)
-            *pix_ptr++ = get_value (alpha_file, bit_depth);
-          else
-          {
-            tmp16 = get_value (alpha_file, bit_depth);
-            *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
-            *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
-          }
-      } /* if alpha */
-
-    } /* end for col */
-  } /* end for row */
-
-  /* prepare the standard PNG structures */
-  png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-  if (!png_ptr)
-  {
-    return FALSE;
-  }
-  info_ptr = png_create_info_struct (png_ptr);
-  if (!info_ptr)
-  {
-    png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
-    return FALSE;
-  }
-
-  /* setjmp() must be called in every function that calls a PNG-reading libpng function */
-  if (setjmp (png_jmpbuf(png_ptr)))
-  {
-    png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
-    return FALSE;
-  }
-
-  /* initialize the png structure */
-  png_init_io (png_ptr, png_file);
-
-  /* we're going to write more or less the same PNG as the input file */
-  png_set_IHDR (png_ptr, info_ptr, width, height, bit_depth, color_type,
-    (!interlace) ? PNG_INTERLACE_NONE : PNG_INTERLACE_ADAM7,
-    PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
-  /* write the file header information */
-  png_write_info (png_ptr, info_ptr);
-
-  /* if needed we will allocate memory for an new array of row-pointers */
-  if (row_pointers == (unsigned char**) NULL)
-  {
-    if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
-    {
-      png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
-      return FALSE;
-    }
-  }
-
-  /* set the individual row_pointers to point at the correct offsets */
-  for (i = 0; i < (height); i++)
-    row_pointers[i] = png_pixels + i * row_bytes;
-
-  /* write out the entire image data in one call */
-  png_write_image (png_ptr, row_pointers);
-
-  /* write the additional chuncks to the PNG file (not really needed) */
-  png_write_end (png_ptr, info_ptr);
-
-  /* clean up after the write, and free any memory allocated */
-  png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
-
-  if (row_pointers != (unsigned char**) NULL)
-    free (row_pointers);
-  if (png_pixels != (unsigned char*) NULL)
-    free (png_pixels);
-
-  return TRUE;
-} /* end of pnm2png */
-
-/*
- * get_token() - gets the first string after whitespace
- */
-
-void get_token(FILE *pnm_file, char *token)
-{
-  int i = 0;
-
-  /* remove white-space */
-  do
-  {
-    token[i] = (unsigned char) fgetc (pnm_file);
-  }
-  while ((token[i] == '\n') || (token[i] == '\r') || (token[i] == ' '));
-
-  /* read string */
-  do
-  {
-    i++;
-    token[i] = (unsigned char) fgetc (pnm_file);
-  }
-  while ((token[i] != '\n') && (token[i] != '\r') && (token[i] != ' '));
-
-  token[i] = '\0';
-
-  return;
-}
-
-/*
- * get_data() - takes first byte and converts into next pixel value,
- *        taking as much bits as defined by bit-depth and
- *        using the bit-depth to fill up a byte (0Ah -> AAh)
- */
-
-png_uint_32 get_data (FILE *pnm_file, int depth)
-{
-  static int bits_left = 0;
-  static int old_value = 0;
-  static int mask = 0;
-  int i;
-  png_uint_32 ret_value;
-
-  if (mask == 0)
-    for (i = 0; i < depth; i++)
-      mask = (mask >> 1) | 0x80;
-
-  if (bits_left <= 0)
-  {
-    old_value = fgetc (pnm_file);
-    bits_left = 8;
-  }
-
-  ret_value = old_value & mask;
-  for (i = 1; i < (8 / depth); i++)
-    ret_value = ret_value || (ret_value >> depth);
-
-  old_value = (old_value << depth) & 0xFF;
-  bits_left -= depth;
-
-  return ret_value;
-}
-
-/*
- * get_value() - takes first (numeric) string and converts into number,
- *         using the bit-depth to fill up a byte (0Ah -> AAh)
- */
-
-png_uint_32 get_value (FILE *pnm_file, int depth)
-{
-  static png_uint_32 mask = 0;
-  png_byte token[16];
-  png_uint_32 ret_value;
-  int i = 0;
-
-  if (mask == 0)
-    for (i = 0; i < depth; i++)
-      mask = (mask << 1) | 0x01;
-
-  get_token (pnm_file, (char *) token);
-  sscanf ((const char *) token, "%lu", &ret_value);
-
-  ret_value &= mask;
-
-  if (depth < 8)
-    for (i = 0; i < (8 / depth); i++)
-      ret_value = (ret_value << depth) || ret_value;
-
-  return ret_value;
-}
-
-/* end of source */
-
diff --git a/extern/libpng/include/contrib/pngminus/pnm2png.sh b/extern/libpng/include/contrib/pngminus/pnm2png.sh
deleted file mode 100644
index d79df2fae0..0000000000
--- a/extern/libpng/include/contrib/pngminus/pnm2png.sh
+++ /dev/null
@@ -1,42 +0,0 @@
-#!/bin/sh
-# -- grayscale
-./pnm2png basn0g01.pgm basn0g01.png
-./pnm2png basn0g02.pgm basn0g02.png
-./pnm2png basn0g04.pgm basn0g04.png
-./pnm2png basn0g08.pgm basn0g08.png
-./pnm2png basn0g16.pgm basn0g16.png
-# -- full-color
-./pnm2png basn2c08.ppm basn2c08.png
-./pnm2png basn2c16.ppm basn2c16.png
-# -- palletted
-./pnm2png basn3p01.ppm basn3p01.png
-./pnm2png basn3p02.ppm basn3p02.png
-./pnm2png basn3p04.ppm basn3p04.png
-./pnm2png basn3p08.ppm basn3p08.png
-# -- gray with alpha-channel
-./pnm2png -alpha basn6a08.pgm basn4a08.pgm basn4a08.png
-./pnm2png -alpha basn6a16.pgm basn4a16.pgm basn4a16.png
-# -- color with alpha-channel
-./pnm2png -alpha basn6a08.pgm basn6a08.ppm basn6a08.png
-./pnm2png -alpha basn6a16.pgm basn6a16.ppm basn6a16.png
-# -- grayscale
-./pnm2png rawn0g01.pgm rawn0g01.png
-./pnm2png rawn0g02.pgm rawn0g02.png
-./pnm2png rawn0g04.pgm rawn0g04.png
-./pnm2png rawn0g08.pgm rawn0g08.png
-./pnm2png rawn0g16.pgm rawn0g16.png
-# -- full-color
-./pnm2png rawn2c08.ppm rawn2c08.png
-./pnm2png rawn2c16.ppm rawn2c16.png
-# -- palletted
-./pnm2png rawn3p01.ppm rawn3p01.png
-./pnm2png rawn3p02.ppm rawn3p02.png
-./pnm2png rawn3p04.ppm rawn3p04.png
-./pnm2png rawn3p08.ppm rawn3p08.png
-# -- gray with alpha-channel
-./pnm2png -alpha rawn6a08.pgm rawn4a08.pgm rawn4a08.png
-./pnm2png -alpha rawn6a16.pgm rawn4a16.pgm rawn4a16.png
-# -- color with alpha-channel
-./pnm2png -alpha rawn6a08.pgm rawn6a08.ppm rawn6a08.png
-./pnm2png -alpha rawn6a16.pgm rawn6a16.ppm rawn6a16.png
-
diff --git a/extern/libpng/include/contrib/pngsuite/README b/extern/libpng/include/contrib/pngsuite/README
deleted file mode 100644
index b2b1537db8..0000000000
--- a/extern/libpng/include/contrib/pngsuite/README
+++ /dev/null
@@ -1,102 +0,0 @@
-
-pngsuite
---------
-(c) Willem van Schaik, 1999, 2011
-
-Permission to use, copy, modify, and distribute these images for any
-purpose and without fee is hereby granted.
-
-The 15 "bas*.png" images are part of the much larger PngSuite test-set of
-images, available for developers of PNG supporting software. The
-complete set, available at http:/www.schaik.com/pngsuite/, contains
-a variety of images to test interlacing, gamma settings, ancillary
-chunks, etc.
-
-The "ft*.png" images are "free/libre" replacements for the transparent
-corresponding t*.png images in the PngSuite.
-
-The images in this directory represent the basic PNG color-types:
-grayscale (1-16 bit deep), full color (8 or 16 bit), paletted
-(1-8 bit) and grayscale or color images with alpha channel. You
-can use them to test the proper functioning of PNG software.
-
-    filename       depth type
-    ------------ ------ --------------
-    basn0g01.png   1-bit grayscale
-    basn0g02.png   2-bit grayscale
-    basn0g04.png   4-bit grayscale
-    basn0g08.png   8-bit grayscale
-    basn0g16.png  16-bit grayscale
-    basn2c08.png   8-bit truecolor
-    basn2c16.png  16-bit truecolor
-    basn3p01.png   1-bit paletted
-    basn3p02.png   2-bit paletted
-    basn3p04.png   4-bit paletted
-    basn3p08.png   8-bit paletted
-    basn4a08.png   8-bit gray with alpha
-    basn4a16.png  16-bit gray with alpha
-    basn6a08.png   8-bit RGBA
-    basn6a16.png  16-bit RGBA
-
-    ftbbn0g04.png  4-bit grayscale, black bKGD
-    ftbbn2c16.png 16-bit truecolor, black bKGD
-    ftbbn3p08.png  8-bit paletted, black bKGD
-    ftbgn2c16.png 16-bit truecolor, gray bKGD
-    ftbgn3p08.png  8-bit paletted, gray bKGD
-    ftbrn2c08.png  8-bit truecolor, red bKGD
-    ftbwn0g16.png 16-bit gray, white bKGD
-    ftbwn3p08.png  8-bit paletted, white bKGD
-    ftbyn3p08.png  8-bit paletted, yellow bKGD
-    ftp0n0g08.png  8-bit grayscale, opaque
-    ftp0n2c08.png  8-bit truecolor, opaque
-    ftp0n3p08.png  8-bit paletted, opaque
-    ftp1n3p08.png  8-bit paletted, no bKGD
-
-Here is the correct result of typing "pngtest -m bas*.png" in
-this directory:
-
-Testing basn0g01.png: PASS (524 zero samples)
- Filter 0 was used 32 times
-Testing basn0g02.png: PASS (448 zero samples)
- Filter 0 was used 32 times
-Testing basn0g04.png: PASS (520 zero samples)
- Filter 0 was used 32 times
-Testing basn0g08.png: PASS (3 zero samples)
- Filter 1 was used 9 times
- Filter 4 was used 23 times
-Testing basn0g16.png: PASS (1 zero samples)
- Filter 1 was used 1 times
- Filter 2 was used 31 times
-Testing basn2c08.png: PASS (6 zero samples)
- Filter 1 was used 5 times
- Filter 4 was used 27 times
-Testing basn2c16.png: PASS (592 zero samples)
- Filter 1 was used 1 times
- Filter 4 was used 31 times
-Testing basn3p01.png: PASS (512 zero samples)
- Filter 0 was used 32 times
-Testing basn3p02.png: PASS (448 zero samples)
- Filter 0 was used 32 times
-Testing basn3p04.png: PASS (544 zero samples)
- Filter 0 was used 32 times
-Testing basn3p08.png: PASS (4 zero samples)
- Filter 0 was used 32 times
-Testing basn4a08.png: PASS (32 zero samples)
- Filter 1 was used 1 times
- Filter 4 was used 31 times
-Testing basn4a16.png: PASS (64 zero samples)
- Filter 0 was used 1 times
- Filter 1 was used 2 times
- Filter 2 was used 1 times
- Filter 4 was used 28 times
-Testing basn6a08.png: PASS (160 zero samples)
- Filter 1 was used 1 times
- Filter 4 was used 31 times
-Testing basn6a16.png: PASS (1072 zero samples)
- Filter 1 was used 4 times
- Filter 4 was used 28 times
-libpng passes test
-
-Willem van Schaik
-<willem@schaik.com>
-October 1999
diff --git a/extern/libpng/include/contrib/pngsuite/basn0g01.png b/extern/libpng/include/contrib/pngsuite/basn0g01.png
deleted file mode 100644
index e31e1c7a635b50e22b6d02ab8ba21f8099b39faa..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 164
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk~Bp9L@-6Me%OS+@4BLidG0>c;6;z7cmE{-7_
zGj-2w<YYGBVZHeJ63Zqp1@0=7{0X8qO$U3q5?$E?KR)QvU-jzJl9rrvD^-Kpo(G$R
z3q2Ctq`2Q(%~sl}SXDKy`_`s;`B|q7GWF(aCg#1&H%R@kUtXZyQ-A4{ifEAap00i_
I>zopr084i?r2qf`

diff --git a/extern/libpng/include/contrib/pngsuite/basn0g02.png b/extern/libpng/include/contrib/pngsuite/basn0g02.png
deleted file mode 100644
index 68809dd8fc0993ddebce8aa9c7bf9bbecbd36cfc..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 104
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk`Bp75C+I9jdmUKs7M+U~W1%@xC#RK{Bo-U3d
y5>t~CIAXub_k1+y2sp$L+}6)%%qgEdVJADoUeEf*_U-^?kP)7)elF{r5}E*i=NeZ4

diff --git a/extern/libpng/include/contrib/pngsuite/basn0g04.png b/extern/libpng/include/contrib/pngsuite/basn0g04.png
deleted file mode 100644
index 6fa089cb8a4ba0e8421ea05d33676856f0cac93c..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 145
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk^Bp4<?JfR7sSkfJR9T^zg78t&m77yfmc)B=-
zXiQ8_NDvSS2{JM(E9B($_14x;S8!&Sdi$bdAA?r;GoK=sfSs$uCMq|ay1RF_3}eW<
qnZ{2z78Jd|r|Qly_4hkjNhSt)k#~&ox|xn3yF6X}T-G@yGywpLM=Kuy

diff --git a/extern/libpng/include/contrib/pngsuite/basn0g08.png b/extern/libpng/include/contrib/pngsuite/basn0g08.png
deleted file mode 100644
index bf522eef0018ae60539ee1b50e98d97906101f2a..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 138
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk@BpAX3RW*PVOS+@4BLidG0>c;6;(>fePZ!4!
zi{9jv1QiAmjuV@CSXq1cIW&KKm$y%-G>{Q7I3+kCJ!Mg43=bP?PydHg|Nfu<(f+K^
hPy#6PU}|a#3q!!ue}#oBxm7@xc)I$ztaD0e0szfSD4qZS

diff --git a/extern/libpng/include/contrib/pngsuite/basn0g16.png b/extern/libpng/include/contrib/pngsuite/basn0g16.png
deleted file mode 100644
index 318ebcadf4fd0b64fb9b824e81c0cc8e3dfd2d82..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 167
zcmeAS@N?(olHy`uVBq!ia0vp^3Lq>1BpBEle`W(ImUKs7M+U~W1%@xC#RK_qo-U3d
z9-UV&8FC#k;BgMLjDBB#?9PJ82Q;dUu4=I?zS(bY(Xf0+xUg{Y0;{G3S&o?ucbmRB
zoML$)c8ASL&0+fj+X+UDyI8k3PT;(to58=tC&50S{f++@NsIIK3}QFDZ^ZA8J8=o*
N0#8>zmvv4FO#l#XIHLdn

diff --git a/extern/libpng/include/contrib/pngsuite/basn2c08.png b/extern/libpng/include/contrib/pngsuite/basn2c08.png
deleted file mode 100644
index 21d2f91a868fc637fdae4fba6c87bfd09b158815..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 145
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnE1SJ1Ryj={WSkfJR9T^zg78t&m77yfmc)B=-
zcyzwKdXSUBfQQMU_07b;+lz#)U9`U}{BiD~_7+|i>jo~7A2JKxKB@JoaA;)W_iC3v
r)WR;J@nJ!Uh4M;=#@z+wiw`h1ZTuN$cYX2<pqUJwu6{1-oD!M<;Mp+-

diff --git a/extern/libpng/include/contrib/pngsuite/basn2c16.png b/extern/libpng/include/contrib/pngsuite/basn2c16.png
deleted file mode 100644
index 1bd4a4d0e2c2c6dd8a2e63a63b26f166b8ef5353..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 302
zcmV+}0nz@6P)<h;3K|Lk000e1NJLTq001BW001Bm0ssI2tcWq-00004XF*Lt00D-e
zG3b_G0002xNkl<ZScTP=!3u*g5JacoL4V7BxBad5mL3KJl7=Q`lgxS;hDGE()}W6N
zLI6H5;F|Aba&vwdJts3?&f@c0ceeuT&U7enqBEEC?ecJ4(E(udvVmXd?D7J6bf&Pt
zKXj(#87M>NTx<h1=<G5A_2^6ifxGC;sb`=Ko%2Z>us~-YE?|ew94KIo9tHTv?hhRR
zwrA%J^h9UxCeR<fo4_daC}8&;7>myPjW#d?oxNFL9(uFDZ1gBle+D$rIj`J+5;}Xa
zfF63WfGT<v$e#gibj~vy@PN*q2>3xy1iYa$zve>zUQQss#Q*>R07*qoM6N<$g1`fR
ASpWb4

diff --git a/extern/libpng/include/contrib/pngsuite/basn3p01.png b/extern/libpng/include/contrib/pngsuite/basn3p01.png
deleted file mode 100644
index a21db5977462c4c0985a0ca1ac2d67ec572d3d17..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 112
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnL3?x0byx0z;SkfJR9T^zg78t&m77ygJ1^9%x
zzWcAFl=eSI>XI5zMAXy8F@$4g@&k4zHj_up0t<whm+&#{mbX7R;pmxWpaKR@S3j3^
HP6<r_p<o@S

diff --git a/extern/libpng/include/contrib/pngsuite/basn3p02.png b/extern/libpng/include/contrib/pngsuite/basn3p02.png
deleted file mode 100644
index 1d0ab6197cc8c4dd61e4440cbe98b2149eeafafb..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 146
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnH3?%tPCZz)@mUKs7M+U~W1%@xC#RK`w#ZI0f
zjEsymdgV<(E>D0@h%3W?AY}Lt#0>va?X`CSX(dk=#}J9B$v@<GbuqR`elYlO@}R`(
l1v)i6D=z*2A<=xsmSL}FePgcHsoy}=44$rjF6*2UngFeOD%1b~

diff --git a/extern/libpng/include/contrib/pngsuite/basn3p04.png b/extern/libpng/include/contrib/pngsuite/basn3p04.png
deleted file mode 100644
index 6dc6eac83f3cf984a4d121e27a8e60454117e12c..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 216
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnF3?v&v(vJfvmUKs7M+U~W1%@xC#RK`w#ZI0f
zEG#VLKejFga&-fILR^&?{xkgl-@))-=|2O*%>Vz>816FsF9(VN75txh7sS~8e>Vez
z3y|e<X@loppt!rIi(`n!#N-z*ICyP~)2^=iRFwR<{C(QF6a{C7soEMIeGFRHkG9G%
zhP=DG`w7Q_Ldg??4o|f-Cn`6b^7U4BXPCOX+FX)};lYtt7kN|r4*-p1@O1TaS?83{
F1OO|$P0RoQ

diff --git a/extern/libpng/include/contrib/pngsuite/basn3p08.png b/extern/libpng/include/contrib/pngsuite/basn3p08.png
deleted file mode 100644
index 0e07f483c0edad13e60e0d475c33a7ca5b8919ba..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1286
zcmWku4NMkw7=I2$3}y17=z>5zLEEca@?OO&kPSTILuD+yid<Q#FBz^`v>i?7W^Q<V
zIS@4tAr;W@A_~TqUM#;}3_1KtXTxr_B{JH)rI15Q@9Fox&)&QL{{R2;{63y%S5;J)
z8x<KBNkmckdGhOcCx!kqr{O7gRA0nvdTG|WED|b@rj8%lNHmR#)~?SHWqQbt%Bsce
ziKKLuL=h|Y5EjH;N`Mgo7FdiSn|YXZS!Plck;t-GmPuj7vPg;}zGpkkqinHl%Pb>F
z0=7twg95}IGPB`0p){BIDdQnXEGb?R1lBYr!w>|Li8PIP)G{}a$YQ`p%(`K)LO3UD
z6M@=IHq>+iwp~U6B7p@ho9?k)W)s^cNfJ5alp|5o3vi!RBHkmgX}UWIuw)VII#g=d
z$04w7jssURBxceP_z6C6HW{SZU_uGkHHZpyqy!k&kY2+c1*akQFoehhD3_nQ9ng;b
z0F#8v3ad!gP>4LFqCR|KhXmq>PACHhpyFVSOH8CTvPiZqN$iqqnyfQJ&?bvale$n1
zTv^)Th9oKqsKIPjfKCD1Cd3{VRFz%0i$*94z+D%LEeH_80824wD<EX~FiU(BniO4!
zA7qm0RfsLC57ZCC3DY1WTccuw7}f(2Y%mutuw>Gaq4ThALK_0kH^LL!W!ET%TWXjP
zf+UjIVU&gj2dkjg55o;~Er9W|;Xj52QG;=_Fb4{JL{~@@LhLOJ3noJ*c>^l+tMCGO
zCYz+H<xYr*gusT%U}V4yNF|R*Vi3J`9LR!U1igI$4|yUz#2$~0IY8@K6EHXupWb)l
z12nrQU(Q<ZuZubtK{KaE)7jk4+PuxnGNfm=l)bg3^zYc}Yu`_Ky)S;)6!p!vq2JqU
zD_aki_<E;)`myQ!)V#4b|Ly(qgq@N&D$FR~^Hu-A=iPI+=3QF7_O3U>e>Pl<|Ld_f
zqkm1#%jMM-%}evv+<)~($raC^D<>wy%g2N5PX<@DWeyA$O75|=jlHcE2YqXoq<-r^
zSF~%<yLZB?@6Y}3WUhKEdR^zx^4q^O#rBn^T(7Llyn1z8dvsJuUe}4|7q1+8<Iwiz
zk>HYo3ID?48vDt>55dBr2eB{o9GWV*`fG5Jx3PvhgDLYTpZ#Qi+|CPMFK>V8kJOfm
z#*Z=w{NC;LVI4^y_wGIZ+0l95T|3etXWUAydp~nc!u}QYkLn)pJU@Hlx;E!j?tzqu
zY2yX+->z>?3??Uzz4BVazO+Xz%j8eHAEZy_UHonH-GsLIpF6E1$sG&stX%!v*c@Yf
zL&of5NeNZAyW0FGPYv%K9`*NV3kUPJUh!4N^d%dUzFDUR&e(zJm#a=^UXXnc(yA(I
z-;o2p70nAqE-$V<zA9DQ_0J;VOk=~+k?fZCS*@3>851jZH`@`r<K1ZCKu_pPNBKF0
Ka(DK7U;GbG9AWPO

diff --git a/extern/libpng/include/contrib/pngsuite/basn4a08.png b/extern/libpng/include/contrib/pngsuite/basn4a08.png
deleted file mode 100644
index 3bb0dd06b510cb42855ce91f1600540f4503ea34..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 126
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnE0wix1Z>k4UEa{HEjtq=#3k+XOiwE*eJzX3_
zJUWyAoIh}Yv2{*{iJ{UQo%@m+%sTdM`xqA|8c4B)7$%qqxF2rNV(Vdhlpzstn1SKG
XmO|}<{e=-g0~kDA{an^LB{Ts5zRx3;

diff --git a/extern/libpng/include/contrib/pngsuite/basn4a16.png b/extern/libpng/include/contrib/pngsuite/basn4a16.png
deleted file mode 100644
index 6dbee9fbdb93f3535be23326a52fb4d3ac60711e..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 2206
zcmV;P2x0e$P)<h;3K|Lk000e1NJLTq001BW001Bm1ONa4iQ{fO00004XF*Lt00D-e
zG3b_G000P8Nkl<ZScS!xUuawB8ODE>kEEkx>-b1@Qb$y-ohUek5*oTfx-A#6y^c`Q
zE+sS)yU66wLTO83iFXm5i(N>*n3Idp^rFd-7Fe(v0)u8Hg(Rko(t3o_;+1WoY3fR?
z;u%**k?mvsIhJ?vei@;3*EJZKPsh^xKJW8B&+`FbWnox{J*QyQf)~!hu>m;#N5~Gr
z*+0X@UGUyz_~;4v=U?IOURb{_zjyb_*+);vGZ%Ns|73^cGmZ_&XO3F(9mBeOCxB*U
zp=MjTt{LzZp}PWF5dym*a0v7!gx-ecb!ZpC(_mu+I?n=c$cJ>2a^`8!UXW*-DOjHb
z_YkaIf>i_R6{x46R)AUxtZXgQHLOFeVC9@tBpY?%Ar~H6|39xka0c+50pEqb_xeL;
z>a}V>WX7?rbS<M<S?RpXg{om?eJ7zi1OC$x$bfzlLK*1EKr;jF40tD@lYz~QLLdiT
z4%$=D%t0duZVuLRurdYp9Mp2)<e)kQQMYDCQeb95i)00Mp9{W|usjvX`sP3z1OJzx
zUxd&i^o&8ngVu-OoraCWu=$7-uyI(<S|7?Y?o+V#I;`A)d&j`p0@Z`CJPZ9N9XsMe
z-wc>B#R07d+ApMY-yAH>T3O$tpzVWT4D`KV9D#5e8fT$B0UQ0W`4d&ZJhZPsBM<Ap
zgVh4m*P!+<sJ3AFHZ0A;*3p_B&45(}^Ihn@k3e8I_<ts_Yh&Ph6c!7StnUo?KY-v0
z7$pdwfb}{w-vVz1Hm^zn-iVy7`(gD2)Jx#J0Lw>V$%MrM45S^qKLL>pn6E&%2tD%(
zfxsaMlx61rFQs$e8K{_6R*OS$5R5?x4}vuajX`MdfzF^5&@Mrv1ZyRz{~eqXESKOv
zC8(4kR<GGxKZ9rh`gTD0Tj-eq<1Y#Uy$SjrA)J0uVE2CjS{zE{NLJH8*P*u;EDKy0
zS}o{wq<~gS&gyljR$*xgDitV|VKDC457(i80;~#ze+@lpFp3bGRtSXNhR`lyduUN+
z9$b;mH4W~3Wo7;Q!8i)m1Z+75jZx_QMha-;VPzJo1z5~OIS+Sk!1m#q9g9K#3PjRi
z&dD|zUqYw|!TTI&UI*h-d9!Cs2xpW8c3lVmez=v7WP^`EUk$cw19ud>Q&NCC3e`!t
zTZ4s<;Z`0-CLBBdHEi7qkvf<Y(Axt>2J|EZXCOGP5NH>n6_-74c*6GZ37L6suXG-K
z4CW`TtWk#kGCXQS`*SIvW<w<oUwi`dao9awvxlCBfeR3gg1G{{X$buR^k*RW4+s>&
ze;)x)gZ678GOZ6~)z<4mILi{)`)Xj6VJ;rYMiMZbfJQ<JSiA=Rz72D?VQ<;7cRmT*
zEQqGTG@+*sp)}}Y5coOxp9g;tG*2P0F#;RcMB%*CvgggWgzc^?GvBgJI*%ma>TN3<
z-w!`MDg}Ig4z9ir2NE@VR~cfbAbJ<VLtq%7e+R)=!G936<DlJy?iuL5r4Z;m3mrq`
zb>pyzjJG1I)@lji+);sjI05nfaPE90J3cN2oI4LMzvS4Dmtmj`)-)Kipf5lm0R9Eg
z($KwIiQO+n{(bK$1b72BlcMdLkBGu;UX?xXbcF5RDVcdAA)Swp!;446R4=_#v$t=D
zz6+p#1O8K>O@QxD;PZj64qX$_)dyW8(DgUyDgtM~$B+D@)ok(ejv=nLaagq78xe(T
zwPerTQDOVyHJSOj^U^uMi$~z)m*DX-4D18zgc`veH3Ac~yc)q}HG(AgY|tG00TSjE
z39l#;mV|^Wv$E%vxUl`|`!e(G+og+_Uy_0jBw$w@Vv`WfKS07T1Ph9UIYq+fpnH!(
z;D2j4rPeSn#<EsY@>&p)`Qj5<wF8No{dies4$}F71YErhP8@dr>U(Rr4MKU)UxPqX
ztzk;7p<_#oYK2so@RX&V5M!xUMP3&^7LnOocI;h>?fN%Tz`#D~+=;_n9NcNR_n;7s
zK<_CC-2h!vLX-smkV2q&9h#r2B=eN=^OCsQ(voQVt-L7Q&L?Hht!ZI9$joDt(z!bg
z^OMk=0QYNHU4=*(%mVbj1IA4y#YrW_j;#XZ?^TR?UBZO(f>>&$BE~W@;n+h@D`@Wu
z$+QV6z?hYpZ?mNH=7bd79)?B(Toc^9GNU(@8Kod-D+Jaj!40VlcSDlQ@=@{gQdwLr
z{<VTME#%S{WY0m^9v+hS1};eF?P0j{6?h&r!_X{1qXOZavg0I#?r(v62-eCHAnzTM
z7`0?dm>7&Zb}S~Y7L5w23`5q-r&J^mkTcViXI59GbI+3oJQLb^Xa=CM0~+5#BMC-O
zA+UA{R^F8K>THn=w^)!Q^Kf1Hd0kwsr!Ly=Ul4@@*>gQCY&S<_=B_E7dnQy&=%m3*
zDCd0zS}ADFD+E>zs2dWUs|O`O4x}A>>t~W=B5CF4X>qmStD@~)iUV3+_B@mqwwnc+
zd9xs$chb^OXB50E(5^x|39aW80`&^qb0xPgtMuBRkPK&4ggm`H%Fo9{P`Y=EwuAib
zKPY=1x*=>g=Va#1fOOs&mBu<b*!V4YN$_F{fqDv@8M!p{pLFbKM$&8F4wd0DD#<(}
zey$xCSL+&41zZ+|3p8cVjhn*ua8734E=uQ}94t>k$A(S{Hf;FuuV#)d7sbeoV@Fcz
z#`3Pp?K3L97A3<4ijriy)kU_eC<XYEqV4{aC|ocpdu}9!?X8r|+)GO5n={~~U^A;Y
zU}b9=D=l|5GbT5do_Wdbp=n94!Eu%0JV`RX_kc6109zT0C-NE`7m*3svTCh)A)FTz
g*gI+Y@|q3*1t0>)4|}U(UH||907*qoM6N<$f-(OD1poj5

diff --git a/extern/libpng/include/contrib/pngsuite/basn6a08.png b/extern/libpng/include/contrib/pngsuite/basn6a08.png
deleted file mode 100644
index 61062308548bc3a5255e3e8dbb7f97932f00eb1c..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 184
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnE1|*BCs=fdzmUKs7M+U~W1%@xC#RK{Io-U3d
z5v^~p8FDok@VGrxPs#9K_}xB~rC;&L-J`A*vOzBbH2%o@YTWE%G>EINoAZB{akFeG
zt2^^4wiQ2lBNnjxnaU~EHpDcAJeJ<z#2<4<kD*ebW77Xe3mDB7R6DRwu@PXo$sieE
f=1|Wl{edA!L2Aym{+H=Ms~J39{an^LB{Ts5#DqLo

diff --git a/extern/libpng/include/contrib/pngsuite/basn6a16.png b/extern/libpng/include/contrib/pngsuite/basn6a16.png
deleted file mode 100644
index a9bf3cb461231de29905eaa02f3a8a66f9fc5477..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 3435
zcmZu!c{tPy7yiwHA^TDknhJAO5;JmTFJcJU8M34%B>R?S{LDp`Fk}h0vV{=c>|`0F
zY}t2XhO#pw*@@4+-}ija_s93gIp?4AJnwVP`=0Zh6Lm*li-YYn8vp<tSZxiX<B0s*
zxS5arg{8cz;{boCuBQ$_A~IzbQf!a&&SN#yO&mihX|^uHBR*{*KjX`EJ@u~4;^K7S
znZ-}x2|!2r#AusQ6tq*1JMtvb@`}-*EUt-U)gGM$wek3M?{Wn*u05Llx2t!WJfnfi
z*&A7X5|P#el2N}!iKN3dU<8r|CRs$6RIMxBPMJPfZc*@iYif##R~J1={rXbTkM2jW
zpAVXUmYnCr)*EyRNatG}eNi2}f3`FDlHQr4b0KIdIQ7?@MDW@Xd2WtcN<E7U8Q@B1
z;46o2QRJ-FF00|Mpjmc3aVc%yx39|V$P<5fkhLdT8c%s|j`z*KbYsP-nhfr*7-1M=
z**hcG4-NP?2^$+yj6jVaB)hdon)Os+Q_M)n*!c!YuPhvKP8%=mDyvp_jdy9xs1ja3
z>unKbAURdar&!F_@9SoS%FU_nL5v4bhxdo;qYV}(%9Z85QFC@Q_IDD58Vx)&SPd#1
z&_z21b`BlfZb@Z16}%Yv2Xg?CHRMe7qkJ)iJY&NQ*3GZeU+ur74iHv1P36E6yN%N5
zpV$8~7z8Rae`?A#-PAcaas4$5zYproUQo8+k=bWG?@3hw>tAT`15|X+#pzBR<JY!n
z@~!3)iYJD6F`s2~fbPC7LAABQBa;bEZSPfF#@)xL!MbbSkHIO=+5*2LT@-F4%BC-h
zkjs~0c=Mp{^gT0<tkslzg{x6EpQ97VPm`-{Sc-IZYI)<5=ZG}Vn4R_6l29D$Y2z_y
zu@G{UX3K2xa$$5B5Bk5>*EFaZTfujS2W+R%rAX5GszY`8KG_1tm1wxz^bYuH^_iu1
z#`8Dkd|UXn0~66IH5Y)%1^wg@FJA3z<g-qfYfZ)1vJ{D1ST3x<9QE-L5F&MF8wPLO
zIub@6gjSVOfP8)*<8))!Yju`hS+5im6`}RB-x-6zb+Y@i6yG6A-Mn<Qo;bXJJzX^X
zyQzp)kGua)ipSxNsO8P|M#QkHeCx87*C!ln3WL7Kp2_o21hngr2H>9$T7YRh1FE(o
z&iHoiEcavc!3({fssSC{c=<<H1_J{E0+6=)8^yO0XoX{i9O^xM-okR=8)j`EZ%T)K
zK`V?Lq0;!V7~^v?MrtM|M%m9q_r3MvMQHKLsuD+U*MlYbGf3edZIEWYDPcALuM<<1
zu=AS`iA<qJ*U1cpS$tWB+^MDAAQi6TYOo@j_1?xFnti6_zJ(Cq1;@6c<)0k&Hb&Ma
z#c_f&L(UCVX2byHRG7tE?~{;pxBFWF{MVrXIMg0z54v}qVTvTs2^`3D_laQ80s11U
zybZZD5*vulpLFppo4XNAnOL5R2vWG7A7*0$Tj+SA(>uH$6|lJ`Cw^#7+?<C$8fV;!
z*@+cdZaXGIsn3hs?nzD2iA>9Oeh5*sk;TrZA_s<KS2~MK_mYQb7}S*lt$g}*5SP0r
zF4*4|lZSNg_<Wn{TEt{fifiuJHU|IlU66X}<qT~0R~!viP0o0v>xq|m5T=dEMGV0i
z^PYDhxn{(1ZN~3SMiq)&y^i<G0J7l`qG{=-$UG$bDa97hNSzFXWE;~}!0OMt!pPl+
z`)(6K;Jf@$NBRGSl$8GmlA$^nf>@u;6U{BWs8VI#ZOVtSIoPu#Uy>G@F^}60slpM%
z4fg4f0@c(&o=lnNB5(wh%7VCL!-EVW2Z|!o{aAn*D%&65S@(Uw9aQtxwD)dfkbS0D
zN4fECZ9%?vJvB6eQZ4WGA92VxeEjiXK}uR*cR55gZ_cQBgwFlZzlpoCI^<hBj<w`<
zy%$QYUb+hC-FdL34$>@-;A(;$?Ag&)@JLm6Q6RE$C5WB$XVqD_cH4>}=w0RmK|UFq
zqT&JFo{xshQhkO07xrmHL<G{dAqdMbW6D>>wC3kOr5B~p#zX7$p_c_}QIK>i^mAbP
z(RxI|(i~*Q0#6E}svt<kWp03&ZAAzZN#C*sSQNKUa{Vv|^s^QPv#jZ9#_r#Gcc#y|
zJR{+%L}CVrKdAL^n@h^*b{)1ZU=V_~zx7%Xg5u8+=DI0$&f*1TKc9fK&xiV8fy9N@
z(B}~CTPq&mM)9VgT6zb2f3zu_rYPIuJ#`wei-xN070L$a3LPf7Rqg^N6BX-dWvEnz
zYk7+Ee@WalYbf})N*@hA2&2?}{m4q{(d9Z)b2noD?ZWT*GY^3kPb27iQQaP>MT(M}
zh+aH!wG#=NVm~3Dv%@S5-kh)W{c#dFYEqq2IfIFM+s<@5JzKFU(kzGaEKDY05{~)y
z&m>r1+fS3X-!8#9ZC}|9nR|zJTO|nFEi^1Tfpt@Ll^mIY?oP}|^w=aDO<B^-y~t3s
z$>Tn=uec<16y1Ij2viXQ-skm0LAjJTsD=F!#DdRhpGW%{rtjIu<QM4&UAdPEhpn=Q
z{w>duzuQ<{wdf>RTZ$_*JNG)(wu0^Ec6<FISH7z7Y3Qi``V0Y7^y@&>FbT<6xqSx?
z_!3zIUUfCS)6fLwA!%9Yvs}RFb1bBZaM#FX`Dt@6LHtQA1;AaBd4qVKP{nI32V#wJ
z&Xh<q3glMv3+*eA)fvL5{|B>LUx0p{l^jo|vK~SZ`ptJ4<ci1df8=h|`_pDZW2Ir3
zc{B_N-u@C<b841jjNHZ!GCJ8mI!tc^ALm<60h675%m6BylEFc9iIWCKvG=M*V4N52
zjsK9T0S$L0Wa`CL(SPISP&AsY6*zxU-=&ni4p;PRHiFcmKB24Y*JGS}l@Yq={`oyi
z)>mne>h=EQ)IBapSiJu{K;#J#&J6T*;znj93+*IlB6?-&YMGi|#xn!fR)W?0*~Y-v
zJb%t6l>}jz9_AsI@@RuRW(OUfTdY%wuhTG}3Ve9pnfH+Qw4C3B8)Pv=6}W4d99_e^
z#9AT03q=Y1K=%(%UJPCeUhitoH`-hON*?knX(%Hos$uAK073oP!1*Xq-mClxyor$@
z<Qr7JCjc<`>}heD;=s0m{le|mRTbo3Wp+E$278tBRf$HlP|fM)?++96CPyL1+wsjf
zVk53I^h-S=*7nAhx<|s)bJ8<VnbTJ&F|j<nRK1cj_D?0_5Kbb`+UIkpS^QWg1#4tJ
z&>w@jBPCFcgym*E9ryTcW-vs2fn~wpR?z?3`C&?_rYej3k<^}V2IPiv-8;{mgi2hH
ztlSGT$s1@-?Cm1cFWbX9F{sRW<Ym(=MXp$(FPu7y9jXvRfk~y@hvb0UghfmDBJSBY
z25ZGi12019mKLYO)|A&8II+^BrUk==a(yST_a@%w!E*-aHedmL4#>v(?cibljVBrb
znh0Bb)h@WE8=d#nxg!?mgZ_jv{v*Mtb>{rWq@mQ%GO4pYbYY3NhtwS%vk@F6@Cv0q
z;32kUm2%K;GCpIm7nY^O2baB-b57D+>*@DbC6}<(k6UKuV_t7>0Ad1l2vQK9%E7Iu
z&(5t^!vq|;yR##&(?y9Bxh>PK;x24md0z_`OZ&EXN0znDnHMLgT<SGV3huKE!!yZh
zBI1Z48uud1lP(gi!oKg@oee98n(-9pkVGMMP%O_Rn}+6EocfOP+9huOb6))ERcA_}
zzC26G0pfmeqzHd^`o`D^;75`%5ZS5E+C&w$1|qi=R2|Vxh1bbu5AJ^Z__j=^#>0vE
z_yTz|TbH$rwir9{GXE3${#InnMxfp1xrN`krccn6rI*N0fJ7fVs@lf)c+k@Bj%@7x
zn2jh^(!=IcnGPq-s=mA+pAQRc3WQ}3(CFdc(eD`%-gjE}`d9j0woiiIO||T#+v6=j
zd(Vm%BvEfmcrs6v+tJ!B*r>Oomj6Yn^vw~qcjX^|m%*OM51be;(%YN8T!+aSl}jzO
z!y8LjI?!s%Jnta+*LWjuuoDMp8d{FnQWAsFx^5}~^aqjGKt--Tz&i+DWSigz|HVB-
z?p9v``EK^JY(aBjc6TFYcV~A?IDo|@Q%5w24{w**chBHLlrK0ny!nC(PsT1>Hqnih
z{Bkl=fi=xu0ZFjuFh^xM2sQ&sXR~!_Q<r2rcF&8=lL>d=m2&L2Axw6>g3OQD`iWxG
zSjeA<d*&T7hR`V#FG+DKwVGd#sCe1=la!hglRhL7`~K;sGLuCbE^R5v#l0)h+oFto
zWXg4wiDNf%@VA@3<z~)t>Ufi`M4@n+JdMglmRaM{EnaIoCk%7r&sK1kSNCR{49-Ta
zj?6y#Lz!(+99uqME>10f)qmtbigTu-hI=Xb4zcPc{eH2<Ss@m4ys2bK^>y_7vv*s(
z*^3PwpUJg-5C=DiVuy>>a!|8$e5K?M)}J02FLf0O{QRMti|gU9y<b_IZm!I`n3S>M
zpsH)mY4<C4uiUSU5^`;8gWq=>IMnhuI<uzwV05L0!*0Un_<I7dn)(_gH|&W20{+#9
AwEzGB

diff --git a/extern/libpng/include/contrib/pngsuite/ftbbn1g04.png b/extern/libpng/include/contrib/pngsuite/ftbbn1g04.png
deleted file mode 100644
index 39a7050d27af28f3bcb7bfc6b071cae91f8c091b..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 429
zcmV;e0aE^nP)<h;3K|Lk000e1NJLTq001BW001Ba00000li|oI00004XF*Lt00D-e
zG3b_G00002bW%=J01xIY(5V0b00Lr5M??Sss*NKu0003<Nkl<ZD3Nv1F;Buk6u@yl
zf=5|QT&^T8CMJcdlS^9}9W3QS9GLE%Ca&~ga-tj)lfotX85|wmBrdWtn6R2Suxioj
zU2POdc-#G^ckiG3UYXoFc$qCha!)I_3-A`vl3A>eGf1AoYPn=%bN?oV&q3&xZP#{-
zd#wGeV8okcyH@o)cboHb1rrf^jB^?sG2T2?@G1n)CJc@hyhCf)&E8%^0~1oF;v>7S
z;6sBJiji@r0Yq=mmR;)Ojr>$W46R-Sau7HO7xZFtI1{|4z%-nLbW<Q*PUN+ZZM>=B
z3o0EAC)h$;8WIR1rohQ#w444G0#1m$Dj66xet|L#R>4C36e7xMM0T)(aSAa2XfV)D
zcEU#my$(kCaRx~QL^LgQ_;=)3gHxFOXBZJd{maEJLqY3H<>rDuET^1Yth7z0>+1gi
X<C0d-TPjWW00000NkvXXu0mjfX5*|Z

diff --git a/extern/libpng/include/contrib/pngsuite/ftbbn2c16.png b/extern/libpng/include/contrib/pngsuite/ftbbn2c16.png
deleted file mode 100644
index dd3168e5c864a81f3284856f2b00fd1e52eb312e..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 2041
zcmV<V2L||wP)<h;3K|Lk000e1NJLTq001BW001Bm0ssI2tcWq-00004XF*Lt00D-e
zG3b_G00006bW%=J|NsC0|Nox7OELfe00v@9M??Ss00960M`fvi000M!Nkl<ZScTQt
z3rrhj902g|lt(c5h;B@c8Wto`5z*MhVpEu6z!sLFwWDPtp>{l69U>r1pj4E?y3$fw
z3LPC~5Eu?Ow>bx*PBc1kWIARHF=os}<8u$TxvBB}f1oy5P`W{kzl6)>j^6kGfA2f-
z`~RHyuLHPP3zER+<N!HM7NQh34+(rt_L4eMKuSs;26c6JfUR58z}T1z96L4zF1}nA
zasnsGD6x?uVlw4{>gr^$apTp%;SiD#R;vJ2Rd{S@z+-2p1bTZD!RV+NOifLIU&uTs
zaE81?yrhgg@q`IfRXqTjnr;GKFNW3KjX}4zVxZ4FgXd*s(ZFE9a5b7MKz26X)$9LG
z&+U!?)zyVy3pqr7Bq1d50~sfsq>_}A+FGpRrY7tX9#13)1Tctg+c1b-yYP7603Ht=
z!sEyY-tFzh#G0G016J#8z+$-u)Ys$P_ICWwmKHpkOd3!^xI`}9Pq-4f{bx<!Ah8hs
z@l!$C+mpa6uVBG1zl=o=4dMBY9azV0ZTAAVI~$CQ#DU4lOTcHJ;r~oe<Nts46&^qN
zWF|?t{_3lEZZ>0*+^SE_VlClnoi%|Y#7Z`h22w+;)<?kbFxKC;Z8rjkV+B~h9t)^C
zPklWGG&p!4n4F9S$B$nHzWD|do|wRK(%*jzsHxF`^Pf;kR+ERxJ~C?p-x3bGo?s$Y
ztCR4M<@R}c!EnnP$s;72WRWk)tO@X-u~-@!ESC8Aj*j^Fu(1CAu(0IhzP{vSyS=T=
zZugKD@*JtTAk{%QbnYZMBsgdl(UX4}#B3vxq&<5i=%w$zi+%OX8JstUhV*(j;Tfre
zw2>xK8=@ykF38Wv&SbTQ0gnee+4}W(MW;&#YW1^ZP6=>`(a|rw5FIVVzI~X$*|S2#
z#!gMe#<mg;niJSWc&^}cJK@e&7sO1se?Lla-pS9$(eTC_SkA$NJgve(dh9VgFDk;B
zORL>Z=9B;j7ZcOd6B9%84Llg;62WOyR`&K*R&qyjI668Uj`Z|E0BdPrAU)mb3<U5G
zZ6-W^I05b?xdb~(Ztk_<{r9niQ>U<mEn9Hr%FoAHNvXu^1_MqPdi^AsQv!Wt=~AC>
z=~5vE2k|lQz4vDV3dQ)iLcy)1R&U>~RtxF%*YPf{2T4htok>Yuq?_=<#C@GZ=iYo5
z=;^^{Ll6SH>ZM@SDqJsaz8SmF;>CE>Y861E`I*cqfgzHR(9)8SfC~}N^;pQUV?snm
zo;VR1X|s8~Hd|WSz(87>ka+ppv`GlL-0PLgx$e0gIE@Ozq2ur@DhdbZ&T-vi=%uA{
zke>b^i2=#U2|%mmwg3D$XH8&?$YhO;GMNy&cVi*2uK^!^h{x}~6Cx|i@6XCoC;|b6
zLP%p{c-`j{LaA(PQ!05pa651syuNY*7#3BC#C5-QYdp~Fal5x-1%_T%hj+WXu_HO1
zSQ$M%AtdlINl7uAQ&Rp+pr!_kf>jutJ}tzOC3gFgB?`sn&6ohpRG^~+6YzMHN?tF6
z)8Gvs_ItfP3Y<KNA)Y#gbB@V$H^|M!&56r}Pl7E9+^wy>9OUJ3g@%v-FJ~DU6%`p7
z)Olt$T~Sd!UsRM3M~+}20|P?D#rb@3aYB0gZM=f}n$%RcJ2lluI1TPj268{JSpMqw
z(#Xj5ATJMVU8TZja7CF+c-LgQ0jykkmV}T1Z)>x&AAcP8jW9H!K(AMb#Kfwq#6%(9
zdJ7BLzaPqwJRVppB))>Rmzmkxnwc3qy>c2ne6jQN_2Kir{~kkZY{cD_MuP+Q&O34b
zF&gnn<>h$S?_Ul|OJ@sx)&y8_ad~-hu@GD!97Re>K|xB&qDB4vixvs-(MMR6-Hvxh
zNAcY06hf_bxzy_5Wv-p@`ik|vcQ5|p=ur%@xHuJLW+o7vbJnfHC+*q8Ezk(u?h8zy
znS_T20^#98!p*WwR#+&LEn8-_E?XwV`1nk}hj4frZEhAqrE)q|DqbZx4c>IDBv*pr
zVf@9&2+ll(g&73fVa*!eeB+b4x^SH6bo<E#Ch!w+xpwVxxnwe{RVFhS)~qoYjK;NV
zjmC(GojW5Ugn02q4rit{ghu0VXf(W9a~iw_)RN1<^Uvciy1H=48jUirdNmGZzaOvf
z-i@uad^x_JzV_NbhyE`K1e+l12*2+pCbqQTczEe0EEe7ifXya^R%^FwwOs3*2JdP)
zfyDr(NC{sqaf&P`z$3h9(pwx3*^-hEz{JE{q6#4acAPX4ovyT0rxRl5PAr`Itk|#t
zTfk<+RzREvufe=Az8$DkI9Pd}fo=ng##=!}#i!tlFXkRk$O$l>qXx;$c0=OV$;L(@
za&nrQa&mYx$7%2ytRYH*og^*}=lHZV906rzC&2V{sF7S?0>KU+o}4^<ST6Vb<#L{6
z&F1=gvzg!KI1TQ2{64jU+(URz$|LP!Vwi{TLeqpdZTyPE-Hg-VHTWUIuPOYWzmkhD
zecryz{YKs-{8r6r@EXi5FihsFM7AKG7LO7a;aQ8ncPvC%3;1#O9O3Vz3s=hj{_FG~
Xn+*9L`l4YP00000NkvXXu0mjf<{8y)

diff --git a/extern/libpng/include/contrib/pngsuite/ftbbn3p08.png b/extern/libpng/include/contrib/pngsuite/ftbbn3p08.png
deleted file mode 100644
index 0ede3574db0fd51fa9266fb1cb91df3888dc8dbf..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1499
zcmWlXdpOg39LGN{C5sa2Bt0E^MASS96&*cI%O#g#Op9f6Tda`V#zwgtX^qWXhM`=#
zI1#55hvk;s&XW|W)v?OmN^($fe!kE1{l1^if1mH`{bIW~+p3~=p#VVD-VW=Aq|W-?
zq=3BGn;D%*C{i&_7?4X9nM~yR0LYKIIJ%!+TU)zIAT%^Qs<O5&DJiMd(aF@*EGjC}
z)+QDf76K&a=jU@OIRb%z&*$gl<QN(fxLhtkA&0}s<YyWiS7v2pT?NR@%xnZ;v)L*t
zLyV}Xw6rvUx|EcZTL2P(goK1ESFQjQ$Hm0~bTgUEn3$NOM+tN~Jt`_HA|k@B+U`2C
zlDt2FFM&<izn_KA#IxBPDwP@#5J0*_()gs2s;?i4Mq{~H3WajK=s1>*waT#qxC!3?
zz5<a*^z`)f@bJLn@n$JzuCA_n0zDiKXK9I1Q+r&ubt`lMbimJ_KcNj26$Ky$G#$ON
zvH~p#n+wnkZ(hDsQ)4RMQ(jtH0^~CfK`1O;TwGKsRe=WpwV=jTgF7%kKM&Oal`uCq
zH#0K>0+^bb0-!+_LIFVlkOn3uCR$oXN=hfy)oYZM=LTO5_V)JX0F)aUb#`{Px3~8K
z45Cm8G#cZ?2?d2q03|3C!N$f8gK>%=kzAFOs;a7HXJsOhsJOUTC=>!T78DfJ0p#W7
zO#|fS<`x6+csvb_-PzgMH*VaxejVY*&B(||Pfw37i%v;TNli^nPEKZQ-I|z~7@ruA
z92Sce8ykD3^-OehbYx^?czAeNSXdrFNJvO<Sa57$U~q77GNMZv)*;t{;!pAQ^@RmE
zmUqnC+xy(PbMP4{h-A&MCJ+b!UyOOiwij$oOvo?{Zf<TaE-ugyx_P?Ww_k#1;OOZ1
z>(?(>_pT_EMw{BQ#m>$Sn!qg3OkVyw9#4k*05u5X^#Wxw8I%DBhvS=>0kTjoKsJnz
zkHa;PN~LfWvNvv&lMD4H5CQz1ooNFD1Ml8_0AO}^ckkGN(bYw&Ct|UTmX?<3ckj?>
zcNB^Yu-39J8}w6t>_9>;(#;tUCqEAdt`EKrw%G5dUucga(q-6VG498*{K%rij4wv2
zoEfW%jzHYO{1#TLQQ`9W=k@mzoI;b9QinWz_A0mp3<fU|ii7Uo6?z-~-FmyZIj*fd
ziZtLyt~2>_C3m`>c%tC$KR#Xus#^maPqG>$Ip&r<7PP}+lo3xrqrK0bX_;b9>)$CG
zYiDOPWRFqn6UcGDpA~Oj9{Dz;6-NwxejzAm$n<rQm6vD7CjXi@@e@{OG5xGtjixtw
z<}TuSbWIxWZPFtOcih}-Tl~MvQ-|(HR(Hk<+6?+FPLV7QO!B04L98aczu=_!`K%4b
zRUW;$6jgEB_F{vY@M%w9H@dWmQG5GUuEU97)3&w^mLgPzp8o7x%QPSVa$_8Q;9AEt
zy@@Xwt-sTLwS4z&k@UjU*Lyt`lf}6AUHvZ_BGVpBP#Z`c_(F4vxVv7~$uDx=tIc^Y
zc{SKq_jGxrqd7}5etz@a<P8B0%y7xJE~mfZAI@5gJb4YOVT{3DLuRIXDs;l>^KEA<
zw~yjS7UP676`?(gNA_%Ti&?JTRiQ)ukN>niNvk-4K4Y-(eYokz+n%p00U^e=@{X9+
z)rI4_;#GQ*EM)A{+^B9WciOLZ)vuJAK75`z`)0L0X_*pJxWq7M<jtvuqAm3Wv_u!3
zXzBchC(@B|nb)^(%CfJML!lNQ!X7v7D%Ih2#XTS{@P}D`n0Uk2F9u7tD0W{yRH|1!
zPU~IV*P*!+wb`iA=JI4j-ye&+(e{CTrY%Bu@<IKkm*4%Qc!l!cR3>yp(uq&jr<7|o
zLnIyhWR@l$6GSYpXJsSmv@J23K`FjDRPrN<`4!1UJg1FhP}`#*W-iAZNy`g6qae<l
k4AflusI^ml&j&%5BB<7^af|q)t%#yvf7%&aV@*!{AM<IOUjP6A

diff --git a/extern/libpng/include/contrib/pngsuite/ftbgn2c16.png b/extern/libpng/include/contrib/pngsuite/ftbgn2c16.png
deleted file mode 100644
index 85cec395c01b305335172fe781aad11e485f45e1..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 2041
zcmV<V2L||wP)<h;3K|Lk000e1NJLTq001BW001Bm0ssI2tcWq-00004XF*Lt00D-e
zG3b_G00006bW%=J|NsC0|Nox7OELfe00v@9M??Ss|Nj60ncj(G000M!Nkl<ZScTQt
z3rrhj902g|lt(c5h;B@c8Wto`5z*MhVpEu6z!sLFwWDPtp>{l69U>r1pj4E?y3$fw
z3LPC~5Eu?Ow>bx*PBc1kWIARHF=os}<8u$TxvBB}f1oy5P`W{kzl6)>j^6kGfA2f-
z`~RHyuLHPP3zER+<N!HM7NQh34+(rt_L4eMKuSs;26c6JfUR58z}T1z96L4zF1}nA
zasnsGD6x?uVlw4{>gr^$apTp%;SiD#R;vJ2Rd{S@z+-2p1bTZD!RV+NOifLIU&uTs
zaE81?yrhgg@q`IfRXqTjnr;GKFNW3KjX}4zVxZ4FgXd*s(ZFE9a5b7MKz26X)$9LG
z&+U!?)zyVy3pqr7Bq1d50~sfsq>_}A+FGpRrY7tX9#13)1Tctg+c1b-yYP7603Ht=
z!sEyY-tFzh#G0G016J#8z+$-u)Ys$P_ICWwmKHpkOd3!^xI`}9Pq-4f{bx<!Ah8hs
z@l!$C+mpa6uVBG1zl=o=4dMBY9azV0ZTAAVI~$CQ#DU4lOTcHJ;r~oe<Nts46&^qN
zWF|?t{_3lEZZ>0*+^SE_VlClnoi%|Y#7Z`h22w+;)<?kbFxKC;Z8rjkV+B~h9t)^C
zPklWGG&p!4n4F9S$B$nHzWD|do|wRK(%*jzsHxF`^Pf;kR+ERxJ~C?p-x3bGo?s$Y
ztCR4M<@R}c!EnnP$s;72WRWk)tO@X-u~-@!ESC8Aj*j^Fu(1CAu(0IhzP{vSyS=T=
zZugKD@*JtTAk{%QbnYZMBsgdl(UX4}#B3vxq&<5i=%w$zi+%OX8JstUhV*(j;Tfre
zw2>xK8=@ykF38Wv&SbTQ0gnee+4}W(MW;&#YW1^ZP6=>`(a|rw5FIVVzI~X$*|S2#
z#!gMe#<mg;niJSWc&^}cJK@e&7sO1se?Lla-pS9$(eTC_SkA$NJgve(dh9VgFDk;B
zORL>Z=9B;j7ZcOd6B9%84Llg;62WOyR`&K*R&qyjI668Uj`Z|E0BdPrAU)mb3<U5G
zZ6-W^I05b?xdb~(Ztk_<{r9niQ>U<mEn9Hr%FoAHNvXu^1_MqPdi^AsQv!Wt=~AC>
z=~5vE2k|lQz4vDV3dQ)iLcy)1R&U>~RtxF%*YPf{2T4htok>Yuq?_=<#C@GZ=iYo5
z=;^^{Ll6SH>ZM@SDqJsaz8SmF;>CE>Y861E`I*cqfgzHR(9)8SfC~}N^;pQUV?snm
zo;VR1X|s8~Hd|WSz(87>ka+ppv`GlL-0PLgx$e0gIE@Ozq2ur@DhdbZ&T-vi=%uA{
zke>b^i2=#U2|%mmwg3D$XH8&?$YhO;GMNy&cVi*2uK^!^h{x}~6Cx|i@6XCoC;|b6
zLP%p{c-`j{LaA(PQ!05pa651syuNY*7#3BC#C5-QYdp~Fal5x-1%_T%hj+WXu_HO1
zSQ$M%AtdlINl7uAQ&Rp+pr!_kf>jutJ}tzOC3gFgB?`sn&6ohpRG^~+6YzMHN?tF6
z)8Gvs_ItfP3Y<KNA)Y#gbB@V$H^|M!&56r}Pl7E9+^wy>9OUJ3g@%v-FJ~DU6%`p7
z)Olt$T~Sd!UsRM3M~+}20|P?D#rb@3aYB0gZM=f}n$%RcJ2lluI1TPj268{JSpMqw
z(#Xj5ATJMVU8TZja7CF+c-LgQ0jykkmV}T1Z)>x&AAcP8jW9H!K(AMb#Kfwq#6%(9
zdJ7BLzaPqwJRVppB))>Rmzmkxnwc3qy>c2ne6jQN_2Kir{~kkZY{cD_MuP+Q&O34b
zF&gnn<>h$S?_Ul|OJ@sx)&y8_ad~-hu@GD!97Re>K|xB&qDB4vixvs-(MMR6-Hvxh
zNAcY06hf_bxzy_5Wv-p@`ik|vcQ5|p=ur%@xHuJLW+o7vbJnfHC+*q8Ezk(u?h8zy
znS_T20^#98!p*WwR#+&LEn8-_E?XwV`1nk}hj4frZEhAqrE)q|DqbZx4c>IDBv*pr
zVf@9&2+ll(g&73fVa*!eeB+b4x^SH6bo<E#Ch!w+xpwVxxnwe{RVFhS)~qoYjK;NV
zjmC(GojW5Ugn02q4rit{ghu0VXf(W9a~iw_)RN1<^Uvciy1H=48jUirdNmGZzaOvf
z-i@uad^x_JzV_NbhyE`K1e+l12*2+pCbqQTczEe0EEe7ifXya^R%^FwwOs3*2JdP)
zfyDr(NC{sqaf&P`z$3h9(pwx3*^-hEz{JE{q6#4acAPX4ovyT0rxRl5PAr`Itk|#t
zTfk<+RzREvufe=Az8$DkI9Pd}fo=ng##=!}#i!tlFXkRk$O$l>qXx;$c0=OV$;L(@
za&nrQa&mYx$7%2ytRYH*og^*}=lHZV906rzC&2V{sF7S?0>KU+o}4^<ST6Vb<#L{6
z&F1=gvzg!KI1TQ2{64jU+(URz$|LP!Vwi{TLeqpdZTyPE-Hg-VHTWUIuPOYWzmkhD
zecryz{YKs-{8r6r@EXi5FihsFM7AKG7LO7a;aQ8ncPvC%3;1#O9O3Vz3s=hj{_FG~
Xn+*9L`l4YP00000NkvXXu0mjfDX!K0

diff --git a/extern/libpng/include/contrib/pngsuite/ftbgn3p08.png b/extern/libpng/include/contrib/pngsuite/ftbgn3p08.png
deleted file mode 100644
index 8cf2e6fb6aabf7c58efda0a953857b318607af30..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1499
zcmWlXdpOez7{_0ij?5*IPSn$xo>J622^AeZriDs|F)fz44lCrgvCaK9(i)p7!%%LO
z6LCs$SZ>MfJV}wPPOIFlR1QvYe%|MK-}ia{df)f+{c@b0>@`sOC;-qn<$!ZVI(j`f
zDj^kjGph?}%2e!GEGVRlO(*lc0TkamJGz}*TU$#c5*r&IR@vH?l$6w=(b>AXMMXv1
zx04DB3jtEEU%$?+<O+pCfk2R#muF-|<ned_g<LK-TaayHQkj#JlL(NVo!tb$;c(Q|
zhZ)h)85tP>^=WBow*aI7Nl8fw2?+qjY&IL9hsk8d#>O5wLZs8_(b3V7k&zD74p)(r
z6#W5wi5%j-eJnyYfy3casnmdg0P-cW&PSbeL&Go(2FJts`1l+vI)>xmtn;h^Zo*f9
zFF+!ZJUl$y-Q5WUf_a*`i;K%{;ch%0Z)Jtm(t1?CX%ln<bi$7xKcF3ym4zSy3>~ww
zvI4CLn;>X`*DqdZX)#srsxB=p0rJcP5Q$0`7Z=q_)!{xs9cb~i;5IBQEI>6tCCtyy
z&(6+*5T>W60ceneP(Tm>WPquush*y(ii(Z4cCD)F{LssxzP`RZfO2EwuCA_*j*dQn
zArvZ!Mq?a5uB3Dcpag{?+Sxf^v1cR6WET~cs;a8FIk{LYE-o$>i9`TRH*Vah2Ph~g
zm;uPo&o2hx^Z7bDJ92Y#uU)%#^(w-Tmz9;3nVA_=7L%5lmY$xTnwrYkv?)0`IX*ca
z2^NbL7Z-QB?Q~2`OjJ}<L_|b*cz6LoXlQ6ict~7eU`R+vDq@#1+?o6{KK?$wzP|7c
zjussC^71-={ycm_1R~oqY>7l7z-JS_iG7g0sVN0Uz}3~&+1VKez@Wfj%a%*<6dWBL
zfByUl>%J=rqtT`{H60urpc%{q%@q~D69^Qz2T+SJUKda<mqQtF@pyr`IUon+1LVTQ
z!~|RcnM?+Wko(Io3JPKVL=u3%lM`)laBzJ59RRbZr)TR{tbqX{Jqd?nw6?a+jE`e5
zZYUH5V6BzSuBoYE1Xx=jTNI*Pod{s_X(Vuc@I7OX`+oBI_A$hCS*LJVx1%|J6!9U(
zXJZZStaU|aApXGhR#uyF;qrxN4R@2yhNUc}54(HsQgRL$3Rxl+2j9CR@-q6Xt)``g
z-CiC|9`vKsoBpwqKhr=ue&f#H-k$rb+X9<xSdG#=3#(pB+93(bm@lN!-saA>PBUi=
zZ<oFA;AA!CzNa=MQP{tolc+6^ejV0hlfs?_1qTnCy(+Ty^yu8^U;8?K()t{BfOV_M
z>?YsBS+ans&A`7&dFaENu<+a*|IhOD!Fy5FU2($py#tmf$d>!3__F$7Rx`n0Xd`(x
zXNPrB#Hf{`Do)y8Y}67x>Fw{qlr}T!YF_4_IUZux-oC*~jH=jeIQPaX!`r{y1WzBl
z(m6wK7D&e$Zg(V>@2C;Wf~LRR?X8$9#=q?zc-|P5aetE9NbV#QTKGtM8suGqBBx#3
zxo@Q}hx+TEERS}!<VYtjsNG535YWhskZ$fi`)B-vIm^+<uRtT5F{D3iZnm=m9YJ4c
zKUcYBj4-;$7R^?K^)4RXxzROtxmv#hP5oE!q$5SIIEg;H_uKc8=KtRGepv|!HL+K8
z#I~(|J7yqRrKiY4-+!DRGl=8O_|>iYl~OZDE->d_uXdy?`@|M5G4?j`=QYAGR)#`a
zvNJkHwy@!`Y;;2I`Sq)+{L9pEnB}|hM@{;rXnr^QKIxlagyn~gH+uDas6<n_=kmeQ
z-PIGczQsMAy4z4{#!YsYry~1*U)+H?71(dqDsrP7Fl>JD-A_hPD*sh|5-pZZezZNI
zTBjQ-?c5``GX0PwW_dm>8`Y+1#_9&A`Q}k652Y3f(u)LcJ9%$iuabnh9D6vUApEqF
nBzr1Qcj<%PHtn77gx$)ZQM<+~5{$JW7KKwMop80bl;r;b+-;m}

diff --git a/extern/libpng/include/contrib/pngsuite/ftbrn2c08.png b/extern/libpng/include/contrib/pngsuite/ftbrn2c08.png
deleted file mode 100644
index 5cca0d621047cacf1637cf7d77e997d51cc6b15a..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1633
zcmV-n2A=teP)<h;3K|Lk000e1NJLTq001BW001Be0ssI2{21+{00004XF*Lt00D-e
zG3b_G00006bW%=J0RI600RJ~w8+`x(00v@9M??Vs00000GbeoW000H_Nkl<ZNQups
z3ry2@5XZm&Qfx3q4QQ1H42F>)6_}Akuqmh*5X4X^rIbM;BH-v?$kU01p_ErCl=u4~
zL7fbz&H-~9!(}3aFu`RZW&unzb50QkgK2!RYsr=o3t~2tT^d3tzx&+X@9uj)%)Vj6
z{|IpB&Yj-g-pR?y{}^!Z-o3WAwzRagh=_<-fB!T`$I~7jJzDL9k&%A|7#|<+>gvkP
z&5eqRQiO&cb#=`%Gt&SnAO*+-su`xq!J$j392p#Z_UzeG0aH^`SFc_zD=UkSkAGjG
zNZGY3d;R({hG_tbfDeIqE;r1<L9$|n7?A6E#mkl*jf`w;Y#bOEc>MUWVZftDkNW!h
zs;jG$lamt?5{`w2W;;5Ta5(kAS>OWD3k(34fhLB@x3Eyz+ozkGX8`3uA)t^*Vq;_J
zARVu%si6?50P_I-{r&0b>GXAy-pZYvJ_kMn+JSRiZt1pd#bWVg8=D~(>oza}`~v)>
zM}7e)8HRFA`iDhFM^mix0K>z>DwQfHCnqyAGc`3;6%f#2ZhqFvO5^8uBq=H7FUwFU
zT6XLhvbG*uwdz+cchJo2l$~8_P|)B15EmC05)$I?@88+kIS+9E{(W+tk&&UwQ56&v
z(A`o(AH0rH_Tk~-0RaJGvDnww_wL=h^8j=?>6z)a6}IeCY}aO2b*Z|fq@=L0@WhD|
zsSDdty^(jSiA*M&bM5WzEtks;bWvVj9&?GoHDC(zc6o7eG4)bKMMY_8X?Aw@u?6h#
z;lshf`|a#hY<3Bkd&JHz$kWs3`0?Wg0OXPTF&CY{G^|Igi;9ZKH36!ss;DvOr&_J1
zx~1t&sZ>(M4;(lkk?c1!`x@w{b_L!AqU`OZt*xyF0OXE$lBa8(+d4*aQ!-UaQ=##!
z_w+pDSx{e4UteEaTT3@Y0IErFaIj1kyl&n1z;8e!i?yF&L_nC8m3(Mu$N-?Zxp_n7
z2DAX*=>Wn$A?4)L>VvOzv*1+iR99Em(9l2wMRh0dROro{PXe>RH6x>UEG*vQa@TOV
zQlU`t^yyOrfcExwL7@Om)cL>za2|4U%W^%=c<5%V3NB?X6h0+EjKsu5@-7xf85_?~
z_(n!?E-s$Cckkx$Tm=FtNq~V#ChO_xan5qaMSv9N2jF-3*7yqRh3Ek)Au1KoO;8fV
zprIvzKyXeU{%KoVxrc`zkCz5CFib&h?McIcn>TN|Dcy8{RDkAq5^L3Kg|$LmUsXU<
zBBJ4(W03sGWO5UeaSET!R&3c4%;9JOl9gkorlAz5VF1mVSE84$J}Q`0nqU|>1Di@4
ze5+F&_hR?T%1UBTp~Aw#cJ55qhku#R59RT^^+74<V`&*UJw0t0K$0tdPps3nGB~6-
z;2WSDObMg=MT<Q}d*)h}7<9t|K{N0Nkmckgv9NfX#R>-!fSSE~<7VgEJh?uUa0qm;
z8Ez47t52=QkANEJ0t(=x^_iQy^73*TT0XxG7zGZwyYCSQ1YB+maEUU=$|_zAke{D#
zTyIS3>>TO5U9}y3y6WrNG#}mt-ZU1(ApHmo3|zUggX&{s6zS#V<>Yh_y5_4hF$wDK
z?p_S=<jE851+BBnIqYCqcy#!(^ULswehH`{(MV{vi9tFjl}eW{|A;(tIN{FDA#8RH
zaFNg7+t&8w>`P`~WeyGw#>B+X26iZPz^D41kPE3=O0g4z6qf*N)=*PsGE4-+(Dp2{
zw2Zxeeeh*hh5=+_V`EuaSwV3@IIpj54kWn}jYdNZ8e`JrO`E(~ENUAnPWZ-+iMMY3
zY|zhwfLVQ0wY0S8#Df-Q7G&8n5<6nh7)vA)kx0bn+nAbqczMM?d^oX?lf?jYc4O#<
zON|S4tujMN`;Hh?Jz7|PetuiGZY4pbYg^pItKUTv6B8tGw0Wp##Go<Ww{IWq7W(7!
z=g(hxd`U067cX91xpIY;HZf?7DT9uVj-?!2Dqzk=M@O|<Ep-<?L6&~%^&Y=7Gc)u;
feXS#J{B`{&ejxm6UY$v!00000NkvXXu0mjf$4>?l

diff --git a/extern/libpng/include/contrib/pngsuite/ftbwn1g16.png b/extern/libpng/include/contrib/pngsuite/ftbwn1g16.png
deleted file mode 100644
index 99bdeed2b3b8564302d449e6578c4aca0f6261f5..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1313
zcmV++1>X9JP)<h;3K|Lk000e1NJLTq001BW001Bm0000027&o&00004XF*Lt00D-e
zG3b_G00002bW%=J|NqFf-^Ty|00Lr5M@0Ys6ss}K000EMNkl<ZNQq<kPa$BSsR554
zpFH{TBUuK#c(HYBU0rHw)J`}3gdYn99|;g`z`J+*_jh)trzcME*<~i86`=l7d8_&y
zy;lLA6TPo&|MLfr0iQk{IWl!>QBlsk;7PU%bhGrgYd5Q9YAv@pu5?I(QEIFDO9PIa
zv;_;!pa1a#&4BOUPo0`ItE{ZJIBk{3V?$2;ETe5E7i<FTWX)R)1FdJfRv1^SZPR7e
zdKuN8msea|RyKR~kt6Tk!3{WbroO(ctP}|R#Ldmkn9b(e#Dv<U$OWi5&Ue1(zTGv@
zG0RTQ{DPWU&b(46$jX{E3vR%jJFTr99W5=@)yW(#p6>FAugap!!JvpW;c(dAAQ8V<
zZ&BY>NjD*)1qCrNK|y=>!VP%!s->l|vE8$;ud}nhz7j7eD@#re2?+@B@p<+PZorQp
zO@$fmNmnXtCft}jxxc@;xf%mh0YPPDR#td8NVBJBWF$%~baiE3DVf#RJVAESq^VP<
zPoFZSy}bqv6c$Ev8{HHsktow$<F==%3B`a(lQP%k`}S|_&z(4N%9QETXU?2Gd*;mU
z?)v&VAgHY^FHcGexukksyjb7_j}Z5Ded#r8Pz;zdCH-R-L#ufI#tHG0Cr>V{lB`di
z{%hX6Idl5@>guwxqN2jr>pYX5E|kJ^f&DqRx(f5PYbXXRS(0v=B3pVK=!U{clUf+^
zwk5aa8O@zLfBu36RaH?@k&$+SvH@a;con5$c|}DEZ2$iLjbgyIZE5`R>8TI9Qu-<<
z%&Jo_i;I%V`!i?Gym|BImy|?C27OhSEj^vT%kqkchm?%||Dqzaq<s8%N?nFcFlY7Z
zeyOTUr5&Y)k<A5_vuDqpJ8xcIUSy<|jBJ3gsJ6Vz5+yDncR{nc`e+8+xRD%@VdIgX
z6W#kJI=v*SWLCtR{7189fs9B`51*tQ1GN9P`FgQqLYjPzV)n<6qZ#n(RpRl~hkn7a
z_Kkf>5gD9C*CIj-6lTnrHEYhC#6(Y5*#J=&#dFf1`ILEld3=?QfBAxDz@I+}XOr8)
z_eUHoTv5Ut_PcOJ$k~z>P;}0k6%}PEBIC}VVH_mAk5_}&Lhw>xFqZ6`_b6dX!jw?c
z%!-;Dfwv2)g69`EgOb#=Y2o48uO(Z#zd9_?))qGsnatzc{v3+|Jw5UA=}QBbWjreT
z8u2D?TToHq>&cU+PVMgx3sZ_0b>T~KcQ<txnlHp7BzN>E76X3$TAY#mJXtlpDYGZ7
zBIi@!?b7Or6DLpZ><kT+F&5$xoMmxVG+rc9{`<DH|NpTV00I{-<mRTPrajKMoUIqI
zu2iYNf8xZ(#?Vkjb$(r*1_1$q)vBH6IsgC1X~6&gZ{D=ErB$W#Wo8D57c2Dk_V-s+
zg@oug@`-TQb0->}crfArf4l~O;$zjSbkp>uelLq>cX#*pmXrhs+uBMi3p@E(ywgBe
zjiXq<a=559;$Z!aj*jl`+}xlbe}8lH^73E5u&KpSFT8)hU_o<pTU$p*dU{}BK)`|p
zfB#}viL++<_wT@g*4DPR#KfSW?b~swB2cy6yEkD%YU-IY_|y=nT)%#O{20Fqifd;8
X;LMiQGdCU+00000NkvXXu0mjf3u}w^

diff --git a/extern/libpng/include/contrib/pngsuite/ftbwn3p08.png b/extern/libpng/include/contrib/pngsuite/ftbwn3p08.png
deleted file mode 100644
index eacab7a144cb54be28f7a5952a2fc63fd883766e..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1496
zcmWlXeK^w#6vvOZ$|54&sN1DSM9q^>(d99%ke6YZ7R$UYR><4NHs#$&Yi#Ca7>ZQf
zh+9gR<t=%;Pf{e)ZIyS6%Ec}2uk$?Toag*?&iQ=5Y&TbXRg?}208||vupUU){h6B-
zkcz#L*@-ko3dRKka%m#d$vj^G`EfVr(<j!~*RK!=jg1d)+1Ztrme%R&W@%{^7Z>l`
zNh~TV0!S$+DBx6a1Ofq{&(F=xH8LV_xm<uE4u_M)&oVKo%FfQd0+5xJ)daw1vsF}v
z=rJ+r>FEIVsi~<q0VDv4iHVmlUj`^)u~-1z3<e`EF7C(?0*ywCiHV7digKuSxQ3i0
z9|+)2U=#N3W8$;$Y&M5Np#%j5kuH)nKWe5K7=)wIST5Gj&+l0AF)SNvoofwn1HJ$(
z0Fg-a^78WZ^u*)w=BeiH?(X^meH;#FWra~!e^jrg23-Ih@csLDXahw>0f+%jL$9u`
zLJPv?JUoFnFJG#wGn8wTmzS3TdFBBKg=I@iODbh5a37!!)Vb<#2No9>p&FnH=I7^U
zXJ<hG)6>%cRLDjsAP4}`!PL}LTibZ!Mq3SyT4m+=!B>O5y}h{r6~@M$ot^FN?Y#hl
zC{!YqO1H65P`C(Cib4@io^-%qT%t%M_l+BG-MTe5CliT8B_$<7p%9>{u&}TmAU{8U
z1|TmluLOX{<7sN{%E`&Oe*OBjYY0DXW@ctaMn-ITY-&boT3T94N(x;~Eh#A}At?a~
zCX*Q-AAhR#RBUW)baZrNWMo7{L_R=RSXgL8Xnb&RXlQ5(VwZBPQ=XGwpr60LKYWFw
z`A2<xe9oRd3!e~yNOp8P0)YVV*@S0ef8O5Ilnle*;o;%t<_7(sm#?>N+eLT=&d$z1
ze*A!+zAFx=Qm40Uad2>eW-t#nmzV#B$CKe6KrO=fr+_k<49bCn!|~0{0XZlSAO|KU
zCg3VarBb*8IU6>}$%O|Jhya1EuGE2nfw8f70F3VL?(N$#dU}ZTL@bux($X?BHikx@
zMxn?6>n$vn+TI5>$O^e=4_7?cei{z`Irux-V<AK7R|mv#nT}Y@>7&^JWYHn|XJb{)
ztaW8aFz!G>3$xX@Xyx4VhMGi|@Z{yRAy3~u3T{Dzq05Alkb8H9K1P4F-hT3g)m9Nh
z8VDfQoBpwyH`740DZKl)ulN4y*5D>vW}_t6!m7uTdPs~i<_W0O@toO~X~vAfo$~kX
z?99fT_mqZ2GV8Z9;>{}~Uxu_<#PH|mLqdkkUKd+?dv$CItbLO(X?+IM&%D`Wc7tc(
zCSF9>rsLiwKlI~HSa@$u_-AGM;JxVT&UitaVZY^ZlI8v>p0qxM*^Cbq*ovReoy54y
zqc@kKDo@y7XjB(I?dj`Amo?MtZokTNvI#Y7Yg4ikp(^za=H6PR`vz8+;AjI^J7#Fj
ze936To%SmgyKal5=cgBHdMc+%aN}M5FB+rM?@v-1Ngeni3qNspgRGNZ?7C+sXI%1X
zu&@5<%1FnPY{|sA&399jf*Ki-lC51Xe<nPbvmAN+8dM|bgE~XzX1gnOBWa6mXR5Z1
z;zyQP!r993o~6UPH+jUZRO?jgQvT&XZBN!NNu<phe*HGw{NLN2h1H-i6MK1QOzYa$
zV|wB>TCyzc{m1!Hy?E|SK;2qE86{)*9AoayT6^+}UtG~L-LQ!_uNscFG7wOc+;n55
zi%O5BBNH<3FJF{p3sXbkmhU1SHR+V;^14{}iC_7{%m7S+(d!q3rCSucFC8q?ub!ax
zF755m+JV|^+;sBNR8-&ZOS{mH!F^^e!qemf2F)+O1xWD<6~CxV>WZY3AMK7S*J*`G
zI`+z}Og|)wnBLFIM>MEg;<Q3i{c|bghZ2j+k_&iF8_BS)M?uV3i94L0A8|@SoHZ4!
iwfsSQhsN%Af-Xf+tzG99^G90|i-O|`S8S~vIq82KKA5Bc

diff --git a/extern/libpng/include/contrib/pngsuite/ftbyn3p08.png b/extern/libpng/include/contrib/pngsuite/ftbyn3p08.png
deleted file mode 100644
index 656db0989ad8403c040f91caa6d1a79d11713715..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1499
zcmWlXdpOez7{_0iP8lN7N%eH-5mECbRCIVu6LJ}*)zWIN!wR`=Y?C{)w8m!2%up^}
zoQPA3!*WZM^CU&GI<0cIayvMc^YcE>`+lGIzxVxozicm0XHC>L6aZ+tx?p_}HCXEn
zD#*m%$mv8xm4flWfKsN!VyxgCfbvH#cVDN~)zxGIp`qbnm7`-xNlC4N0Y^`-xVU)x
zc4ARc5kUI2YuC7yT%k}X5D4<~^G!_&JRT3Ah|A@21RQho%G})CWB?9_(+I$3vo$mZ
z=y7pbSy=#e85tQj0b~FvDJhpOT>=oZSS)~U27{51kZ|Y_fkvan#l^+M#JE(uTtQA!
z4gv@uunBwiF!3Bbo6V(AD8a$Oqzfe7&$^k$#*t_=mWTEC_dim61k1+S<=X+=fH{C~
zKqL}Ro;-Qt#0fkeZ<S%??d@$OG{WI<wze2;?MHQ5TF?d10pGuWhc-}E6@nDdH1x{K
z3bY_>LZKPnzIvst%}~3mwzRYa$TJT>Br088T+}GlfcpTopv}{U+b}yj3)KLXFf%hV
zH8ll7n3$LVph7M}0YLze1r`<-`ub+;*E{Iw)TpV=^uO-!?d{D6C^s|f?CflBZ|?=@
zN1;-vRJy&ripm9m5)_JX?3fD%;}Jt5d9PnzRaG@Tt&m70VzF2x5&<+`zka<Aps=uT
z5}=@<Kn%d=^L2H1<mKgEy?XV^6@(uzCnqO6J3GECJ|jCLGcz+iJ)N$lm71EGl$wMT
zlgUg>Og!FtJU%`?Ha0doIyx#Ust_O|A|gC0JTW9BJUl!diAx#Qt-#Gc$Uh(;0OsLv
z;o&o9&YV7d8onR~ksRrc1Ofrzt2y7?In>$0f((P;<KyGy<pnRmu+VVx<_qu?+}+)O
z{P+QDxhsyOQYSWUba8QkCa?;zQdVBT<H>Ljpax;QW}rf$fHL6XZ~`kUKn^MZ$b-?*
zQMe3pxg3%q@0VYclp=!&M1UYqPikLZ-^j=Z07iFr_m(XfLqo)RA{I+;X=#}p89}3c
zQ7AINY72|Cx(f1<1BfS}6zk)O2Zt|%A!|#3n=^L7>E-reBy>5hSd8!C+(5GA0R5|(
zCU?rNq9X*i?^+A9)vRdw?6dm2DISq&OPK>F&h1k13hobIB8bE8-4UHJ{j2p>b2F>0
zJdV^CNUpQ^W2IoSo@jsl&fn+!_ExusG&(RFWck*%JvP(>Qj{5ANTt5dn`)V0Od8)V
z``FITX~_FXsZSxZemf;qUmltp&}R`NpM{2n4OqS@w(~pLu_37DZPJ+CDa;Gz%|^=`
zd}}Z1EV?EO_b%<BKX269Z&T7g%M<(W#a4GF3foLx*c>I<>>cOJ>%y2#_#mN!^x5<=
zjJGmcy%bg9<b1wCTlA#oc{jSWiC%l_b%C3GxMf@0I$H^<!pL~~oo&{+pmK8@t?zQj
zB&|sx8?L|Io?O1;mP8&p@$GI;#kd&vzU#%yhS;q8W0VF`2foPKU)o)-=oA!t?%K|M
zFMHkpyza^JP)BpFZ1k-9o%D6V4UA~nrY?^^lO9al3_X4Wno;!rZ39-8J1Y#LX|rvo
zDmM?~hZb3)sfx&+#e+LH_#`Y>Z>un%{403Uo~AEOp-q|0FAO&Q_payLN^pd^v$8v;
z_2>K%L+MXinj+%k=b2%{MBZdz?a#ncO7`Gc#`N2t?P<&Y2}MhElSclGW+d9ySV&Fv
zGKiPYu6ryW8ddns&8aEAjSocHe299~xUJNH-^IF5oEHo-12IXaZ(jD7Y*g*OxWCk>
zdX(C`xVuAdD@xt0@z}-jnCHJQ?m)YSJhyBS`I7e;H@#X2l;c&(f7KW>kjTeAJ04Z5
z)r*jI>{i%Xd`gip{hpQ$=}<Q&=!Inj<WtBGW!9Hu=keS&l1Xikij=XOa4@Sd>bQ!O
lGajP1^htlK&dv|QE>+O1S>+WAhFg({f~%7!w#Jd1`acy)otOXs

diff --git a/extern/libpng/include/contrib/pngsuite/ftp0n1g08.png b/extern/libpng/include/contrib/pngsuite/ftp0n1g08.png
deleted file mode 100644
index 333465fcdc9f10f7f25b2d999b558f5421983ecc..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 719
zcmV;=0x<oFP)<h;3K|Lk000e1NJLTq001BW001Be00000RuLsA00004XF*Lt00D-e
zG3b_G0007pNkl<ZIE`bdCjb~oRPgxZM?4B%Y^_U;a!XwJ5UYZB`#aMUea*BqR5bJh
zCSLi2s^HU+sYN-#c6tUn>e{x-64Dw5ISbDJfGPNXYF1fsnx~<Gv8j!ng`thBvAV8y
zR9<n}>?7~M3eMD*m6rOMo0;2$rUW>-c(^**S*Ycd0zuX+u!1|S9WB+#F78QX<>lo?
ziQz$h-hRnIW<gBQUa*2!EsgDco%NNdpe#8gz~>oQ!H=elq>2fX`<ts_psK1eD?Gr*
zGZN~HuFR6Y{z+4(Pie1#g2HHH5eZ$lCa8i*nfd+w6Q@j{IeTVzeO+B`c~Xd~xF8RY
z{u-!)De0Ll{SzinuBx9tZ%$ubR#dpIv=A=`x5_oBf+guGrTzVrn)8zL=FVSG6%}bG
zE5<9uD`NK>s$g4Md}>$Ugu1e*ygBpcmqZ3DNb_5HNEsBtg8Fz$MsRgsRcUEt!R)#7
z@*=Hdg|%Ijgaqfp6x>M8@W|<nE-8t~pEY}KdbqN*fVsF3pV)Djf>(*DezA>78ATBV
zGiJ?6^pq7<lHudwQT_r`@FyWTJfg5TyfCC>`pj8TmNNXtGQ7M(fr#kNOGpUKtO+a#
zE}lAlTDXoRkAt?j2v0jgK~H>oU`AO)UQprWsr_L}qI~YALPA1E5ej}SPEJnGOv?!@
zojAEOR7Ob9QdC4?8%mP9keiy8ksVOlKd~`Xk)KCEK=mA2ntaoimYx|<+}mFjqR+?8
zZTJ8q(f(PLp6*}V-CGiDD=qBv7F)8vQWR0&(VZLQZ(jZjd%k$Tpt-FhJuqOwUu^jT
z1pXapZA%Q=jx2<p_3lkbJyVZQLH*aq_4pNF008$!%u(56)m;Dp002ovPDHLkV1f>U
BP!RwC

diff --git a/extern/libpng/include/contrib/pngsuite/ftp0n2c08.png b/extern/libpng/include/contrib/pngsuite/ftp0n2c08.png
deleted file mode 100644
index fc6e42cb420fd08ecd78340256157fa5f8a22934..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1594
zcmV-A2F3Y_P)<h;3K|Lk000e1NJLTq001BW001Be0ssI2{21+{00004XF*Lt00D-e
zG3b_G000H?Nkl<ZNQups3rv$&6vzJ`6dKHj8c>u542F>)wJ;-zU<0Ta5X4X^rIbM;
zBH-v?$kU01p_ErCl=u4~L7fbz&H-~9!(}3aFu`RZW&unzb50QkgK2zirzKlPEQpyV
zJ88Z&UwhB*+;h+QpNot)Z1^7mZr{G$*Vi{SHT9YSckkY9Z*NaePmhd@j0*@zcXT}E
z>DjB%+#enNPk@PuiSF+1yu7^V=xBLZ*b!IPd^0mOpafEZETD#AngxPxg<^DQ=;_m^
zO9f0%PhYumrM$d6AtB*?xjc2}&YX4Y${D5+C<Z<R5?D4|AP_HKE&^maUWu{sk*KJq
zrl!Hc!AFlC=?6S~_^`jfzow=pB_$;>G4W_vSdOD(DVN&-oB_@QeZU}a320`R0!vG!
zgF}Y7c_vT+6ajLvI4&-Z7Si(C+FA;c5-<-iFfc$*`Z-x=6;4i{1D^pMz*&|p+q$(x
zB)Vj4J8WQZ3z!6c0e;dUzW@{rLwimBm&L@yP^|L+BO@b9r7|}+H!CYEEiFwM7}#lU
ze#Y8b?eBj$IXU%j%aqGow{IV|u^C^v@>iA}GBZ1AZ=V(%{Ldfa<Ksg^LjwW=y1KgN
z0q)(qN3Jt7GnKi@!oos2TYCAys~GJ*A|fI%Fi<2C`T6<XxpQY8Kzle@8FrO+oRb{a
z7FSi7s<gDUsHo`p@#AR=+Yz0Scgl%WDxGuf<KrWf$@ElFettf4k-=498nO;qNl6LS
zQe|ajSy@?5PR`K<?9ib@AtC$h?Ufu(Da#(Vw-5I6@;!F!m>vLmWItxn1<b%^)TX$&
zm|PQ}y1JSQgPtmtivE_aGlfDy8Q;HuzgWD_%<OAmfXWqk7l?LnkhHb6=>d>CixU>w
z(z&H&q%@~cmeiGMuLdu#(_V!Qg$)f2b#--gLIj|kgoK1hr6FtAeh>TxG#MD|V;DCe
z+}c_;JUpxi(9+VfzG^*Mf$y{cVZV^}<lE+pue813RO3`%U*Fi+NDW1KC-0Q#O`A>t
ze*#wx4d1b}e2ZmQv#dlY6hC?LL=T{&qk~_>M>ADEa39<U+`RHU&(ogT9;=2+xeJ9)
zn;=F~QWAL=iK2~+W+{9_!*~}LuU)%#Sy;I8`4W-<J)KO}+uQ4$?TiZmDb5eT@9?Yj
z6E+CZ3sk|a%#BWhHbD$(S_1I-XLaG9va^$Udiq;fqyvo%Q&?AbLO<ZfjT`O?cP$_d
zpgx|$8r2$Molsj>m2fL{qvo7rko-xdG82;t3ZKJ~Z{8fj<!S(um7}JnVHBu-0QH)8
zlD9TLN|;ocU<5b~+bUapt5qD25|65?Dq>Kg!o$ON?8wlCe~HHnv#{{d1tq7Cl~vHp
z%#3~jNv`NUkyhKvAxIVA8=wbFDWm<O!S3SSb0td*I$=J)1^5HVc5)J1TE1;y5CJ3t
zwR`r&XUw;Ga(yuIAZTF=+#}srom_<<0Ts{<6v9{IJJ)v=6&2L9JYG961|0P8*v;qj
zSvD59NIS^RE?EpvP*7mhU_|Qd9Ob-Cxefi=>}$)k06v92)E2}b{Rj#QTCt*&@?&Ti
z<?Ze5<a7Yq;;T0?3GV6XSq$*_@ng+-jkD4@{6Kg_OoZ_{V|=0;0xF2rV(M*TkPb>D
zl4Z+2B9B~dgtK!fhf@n&;PLjfw||-Og6SEVLqkKcv9UCP1w{gUs+$RUkf<aSJ26Oc
z39x!K6=fE~L^2Fb&tfa9xNFyjUUa1&KsG);o}HZ?93PBxy4>bMoF`VR)x@ASCQaVB
z(Z|4m%7&5?v0+2f&6_{#^|K%#LswL-t*u(|pn;hUX^xb{ju_O&VzJoG&5g&iH8u70
z_D*>4U~(ZRivi~B`tWs^S{JHXMW%x09Wf|-G_d^r{kLq{LV`-iwz!9v--{+ECrRLF
z@=(%<L2bNu?_QcM^zzxWXD?m8q?_II=g%)+zDz@#7}UnJgU-&*r7T=3V9v(I#xxoY
sRoC1V<n;r{W@l&VhWbiN-uUhMFIDPP%w_<`9{>OV07*qoM6N<$f`h#14gdfE

diff --git a/extern/libpng/include/contrib/pngsuite/ftp0n3p08.png b/extern/libpng/include/contrib/pngsuite/ftp0n3p08.png
deleted file mode 100644
index 69a69e5872234d96cab4cbb017a0933fbfedba81..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1476
zcmWlXc~H^`6vv-Om}J3dn5OOMOgg5aIm=3#R<M+qH<wwuc|s$3EM6p8%6K6u9;kSr
zW`|a0q1&OE)~;HVyY8fRxoAa*<$-H!x*ps9dNc36f8YCjKcb)j@6G7#XaLykL#5D=
zZS$=+8X%K$sc-;Uh8&VV3H0(BU8gEf0O(Hy`7sV{-5Q_8V%@%duZ2u*XlPK_*objB
zxm<2#6<S+c3y@P?T`g&rR8>_~R8*9gm+#ueDlIJqsFg@0;tH{|b8}HqQ5Jw$Ebasl
zi9{wQqx{s={QP`?_T1du%K+m5+1c6W&Yc6O&&<pOPznTs)2B}piLCVW^wiYU<m6=P
zRcbMEl70+86idW%a5zI3(?uc)hr@}DjSY_vH`AEq+1n@L@sv_ZWMt$%`96w>;#KYi
za0xyG{0*U@p&=n5OeT{~rxS7s!NI{ht9Awk26}jqu-LA43<e$p^uyZP8vF)^hE?zg
z@ag!Kl@;hk*qnq1@MdHLixn8(FkW6>2IQH$P*->1%a<=E7fhf7KmpiNEL?|$g$1|@
z&<t~Pb2BqDPz9epeFES@5kdh$0FV!^uCA7rjz&fYO-<X3jpv463=a+tmIGXLbQ~BM
z=<Dkn1Q<r6v$<UU{{039@c<2IH0$tTDv9Ku93CEQWYp5qGCQklY;3Hrudl1C1L&-&
zsc8q0$z;<2m6etC08**c%*?v1tgNJ@q_`O2S6WzDSWr-q)|8f8keip6my?sj$6$m)
z;aTBXq|Tf<laY~e<l&LDw6v6z6dsS4l$0a`NJvPCONz^2v*Y68au8jbD87}xkui}`
zQBm*@?3L{e3ky4T>=;ZU0fm$KWEP7BFz+mN_CD$D>KXyBfJUPQ1qHz$U@Noz`t>V3
z0Y5*#_4Rf5=AAr|%l))v3zbTRZXmD;`udA>dIa18XhRr(3s9%iK@&&<11kswKn|(|
zC<Col3+F+tRznt)p-_5yi7~8DfS7;)?$FSXO7#{%pj0Z&%}KVlNc5o;3ct6vcUq;w
z;~8jl1i;tc%uGrY>Kfuzi4TRu*jp4GWDgcp#{666_U|?<$;@lL6fyrT=v@~MF43;U
zZ$6b_)kkb?TQRlFx@L1DFHuvCdiGRV@qSb5o3SyX=dqWIo~SD}lgtU8-0hinIc|l^
zwZpyIy{+Kp3qku~jyuQS{wOJTffqk}ylg!rGf@@8WYp~qR<LMm=iRWaIs+%Z?EyiL
z$3>TEe@i_6M#f}U2WR@4MfM<b4D-Oq=}GlXLVBLG9p!kmr+;x?B)}4PFLbk=es%FY
zu>)1<JbF~eTkdn`w79VC<h(GqB1wATjH$!XPL+ehk;YhC#-m@R3T~JS>HJRjPCMx~
z7uM(-p3*y>&A)fhi1A3;cS(L+J1;&pqWL&it>CX0-+eBqO{=g-lKzNGvG(`sNqtRF
zeg3%mDzvL|F3Eho_0DyETn8H%dc!?dA!#0>Q=Vr9#{-Ga&|1#6CAW+Q0sfY$`N-&;
z^0c=#@%4)8jy6X3lL6u3JAW=?c#tm>K2a$#(Q?|Uz}T^+pWADD@MB|q8>&Xr948aj
zsY1|Z7&ad@u4wr4W%TE{WS7U&Rh^yI#(OsCtq$vQ3|A*M_uLm%-A~M)I@BiVUy<b2
z+cpViZ*y18Fq8S3`1fl02U-`g`*s1z`K957gEIq~O=*uih9>S#YR$&g!`CNx58tIE
z|3D@=NLJY$Q%;J12ZU?1w#&^2c5EzDN05DZLoa2szJ*SEwwg0|Mem<$Yn1cWcz^cq
z-}lxrB6iz%k1R&3=>`|KS%};k)l(YskH!jI!g#-(&O>3hx)5(GX8X3fe_&q16?&Zr
z)72bEymR&OySDOI3mZ0C3tSEiO=8X3u^BG}uBukDWrMyZ$LQ%Y4sr7@il=hRi%!IK
N0G~qvls0mN@PBi2fm#3n

diff --git a/extern/libpng/include/contrib/pngsuite/ftp1n3p08.png b/extern/libpng/include/contrib/pngsuite/ftp1n3p08.png
deleted file mode 100644
index a6c9f35a86271c056e955f637a8769381eb03827..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 1483
zcmWlXdpOez7{_0ijw~Xj6ZLfH5mEEBP|@KrEtkTuS}m>SI;>1?8{6D(v$V!$$}kk^
z;zXQM92O%H=ShmnbXw(ZQ8_r3^Xq+{_x=9)zVGMz<@$KL>7tBL0HEvPj`Ks*<Y%we
zKql^LZYLs|RIC>k)Uu?Q@xn6z>Z3lMM-Q#6tfUZ$jg9xOySS8<mDQP;@C*%0N=i0w
zCKVSK17uvje3@U(7mLLrk*J`cz|xW^5C{N@`FuW4#Iv@p&dbY70pRg?O#oajS4U@%
z85ftGoefZ*nVESFKmm}Nnwp%P3{cA9Z~(elELK87!oGb(27?h77Z(!~<6h%_5jjac
z7$A_yCGOb4Ch!PcE}u%JhJ=KW&ym-ESf6EXPDi700$e~qz=4tjI4;hyz!Bgod<K{U
z5{Y#D`0-=Mju8k1+e}+uUtcq^86J;!aKP&8Kd9H!gDwC$eEaqd+CfuO3^G77(96rq
z(2B4LgBE!8{JFk9OZ&F=;^HD8&)frvq<mpvL8n{??gG?-zCa&t!u<R^)Bse&?Ck9H
z^fZWJa&i)Y26+et1OY%cU@#aXBP%T}X9I&;ZSC2C7X!V$y#)Z3R#u&zogEz=y#NC!
zR4R?ebaK+rI0sOMLJ?hE-LY7&7&6&cOY8de>oYSdsZ?58S}Ku90Gh5`xl#{MR8%wt
zP*_-43Lq2;*RS7_pPzr}(xr<R5q^T)+}xa;ocN0P%$&@utgMWT45pr5T3T9CS`t!h
zHajsf@o?MW`1ttP*x2ak=%}cuB7n%q$cU(j#L&=)h=>d%E)}>Vg+~H{0|EmB;S209
z+JEZQsgoy9!bij)vJ2CNNF)M$vKCsqg}Grc6c_?OKR+KIALs+qBGU~U&cS2w^z{7x
z{X6{3T?w5=n_Ror-Q69U!8X)ZUHvP8K!G~|wFu*%2C7slr~p15FS4}-<e)-;d>9)W
zgA1TkDj@~(fB8jCjUG%S0R(${)B5}SM@HTPu)4duH*Un5nj+Sda5!dbYwOg=2pWA9
zg`xngv~oCl+wa{*R;b1Lc@x0-<4`CPvRn@w_UQh+Ac}Mk^OKb>f7-E19*W;}xs}~!
zRlIciNyF__FM9f7*5I)-+cbPa1|k-TrQvsONlsb*)pnz$h0|UcNA3@z)MNfwE}Uv0
zIbFH+_Zk14HEp3y&g@1-ft^E-J#CK+WhE5TXruYlt&^-N^P3g#I=H!w`R}L=sT9s{
zCuD1uhCdG)aY*zhVd3F}HZMyY{g2C62iLwz8h1Q_?PFhSvbid>^O4P?YqRlh((eZd
z#_aspCH=EBx%*CRO=qIG-J;L_AlZKBgiu)@&Tb|Ii=AapW?Zqp>gYA)sH#J5XB+h;
zk9wYVqsyC_bvIrV9&w7WX>VWUAVpP~na{j&$UYNXX^m&}Uyx5RnnjA&4L3VdD!1H_
zD#Iq{ZueA8l;TIb`kpn$X5SsBHj?FpV!HrYcY~@^RN}pDGk;X^V&G~0qorYaOP*rv
z^qN~4t3n!C(Ta6lUVkRto3S5$_!4xZm;=Uxwl-U<Orja{?I)@?ye14Ua3s@J^qz&i
zTUYxfEY%oSnNa@~J?cm|DotffTYULC)coI@p1I|aNNYEBPi)(dF9%FzKN#t%$af!R
zUz;Whrh@8z1eH^BhEB6)Uj67uUkXSlUSwJ{31@ZbXa{pKEzQRyUOB(&p>lXk<^TD!
zwrXx-kZ%7r>OqrnxrwlgbC>i*G{g?VCRx6GHc+-!v-|w+a<iH-TJOSkx#1?%8mlJP
z^Aj;oe_z;w_6U7y(<(Vi*=64R{A-Yspi%j&&bWzGIsU=rpmv>Mq(Z)3<$!sgDrNgW
zt{66;txYft&kQV}Qtm74k`-qO{C2WMU5|#0wUn?oyC~|ghKx56YPk5`Xp_O#x8g2M
X(5+n&l!#upArS?SL*BSr7fRay;V71Q

diff --git a/extern/libpng/include/contrib/visupng/PngFile.c b/extern/libpng/include/contrib/visupng/PngFile.c
deleted file mode 100644
index ef0984e4df..0000000000
--- a/extern/libpng/include/contrib/visupng/PngFile.c
+++ /dev/null
@@ -1,450 +0,0 @@
-/*-------------------------------------
- *  PNGFILE.C -- Image File Functions
- *-------------------------------------
- *
- * Copyright 2000, Willem van Schaik.
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#include <windows.h>
-#include <commdlg.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "png.h"
-#include "pngfile.h"
-#include "cexcept.h"
-
-define_exception_type(const char *);
-extern struct exception_context the_exception_context[1];
-struct exception_context the_exception_context[1];
-png_const_charp msg;
-
-static OPENFILENAME ofn;
-
-static png_structp png_ptr = NULL;
-static png_infop info_ptr = NULL;
-
-
-/* cexcept interface */
-
-static void
-png_cexcept_error(png_structp png_ptr, png_const_charp msg)
-{
-   if(png_ptr)
-     ;
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-   fprintf(stderr, "libpng error: %s\n", msg);
-#endif
-   {
-      Throw msg;
-   }
-}
-
-/* Windows open-file functions */
-
-void PngFileInitialize (HWND hwnd)
-{
-    static TCHAR szFilter[] = TEXT ("PNG Files (*.PNG)\0*.png\0")
-        TEXT ("All Files (*.*)\0*.*\0\0");
-
-    ofn.lStructSize       = sizeof (OPENFILENAME);
-    ofn.hwndOwner         = hwnd;
-    ofn.hInstance         = NULL;
-    ofn.lpstrFilter       = szFilter;
-    ofn.lpstrCustomFilter = NULL;
-    ofn.nMaxCustFilter    = 0;
-    ofn.nFilterIndex      = 0;
-    ofn.lpstrFile         = NULL;          /* Set in Open and Close functions */
-    ofn.nMaxFile          = MAX_PATH;
-    ofn.lpstrFileTitle    = NULL;          /* Set in Open and Close functions */
-    ofn.nMaxFileTitle     = MAX_PATH;
-    ofn.lpstrInitialDir   = NULL;
-    ofn.lpstrTitle        = NULL;
-    ofn.Flags             = 0;             /* Set in Open and Close functions */
-    ofn.nFileOffset       = 0;
-    ofn.nFileExtension    = 0;
-    ofn.lpstrDefExt       = TEXT ("png");
-    ofn.lCustData         = 0;
-    ofn.lpfnHook          = NULL;
-    ofn.lpTemplateName    = NULL;
-}
-
-BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName)
-{
-    ofn.hwndOwner         = hwnd;
-    ofn.lpstrFile         = pstrFileName;
-    ofn.lpstrFileTitle    = pstrTitleName;
-    ofn.Flags             = OFN_HIDEREADONLY;
-
-    return GetOpenFileName (&ofn);
-}
-
-BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName)
-{
-    ofn.hwndOwner         = hwnd;
-    ofn.lpstrFile         = pstrFileName;
-    ofn.lpstrFileTitle    = pstrTitleName;
-    ofn.Flags             = OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT;
-
-    return GetSaveFileName (&ofn);
-}
-
-/* PNG image handler functions */
-
-BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
-                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor)
-{
-    static FILE        *pfFile;
-    png_byte            pbSig[8];
-    int                 iBitDepth;
-    int                 iColorType;
-    double              dGamma;
-    png_color_16       *pBackground;
-    png_uint_32         ulChannels;
-    png_uint_32         ulRowBytes;
-    png_byte           *pbImageData = *ppbImageData;
-    static png_byte   **ppbRowPointers = NULL;
-    int                 i;
-
-    /* open the PNG input file */
-
-    if (!pstrFileName)
-    {
-        *ppbImageData = pbImageData = NULL;
-        return FALSE;
-    }
-
-    if (!(pfFile = fopen(pstrFileName, "rb")))
-    {
-        *ppbImageData = pbImageData = NULL;
-        return FALSE;
-    }
-
-    /* first check the eight byte PNG signature */
-
-    fread(pbSig, 1, 8, pfFile);
-    if (png_sig_cmp(pbSig, 0, 8))
-    {
-        *ppbImageData = pbImageData = NULL;
-        return FALSE;
-    }
-
-    /* create the two png(-info) structures */
-
-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
-      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
-    if (!png_ptr)
-    {
-        *ppbImageData = pbImageData = NULL;
-        return FALSE;
-    }
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr)
-    {
-        png_destroy_read_struct(&png_ptr, NULL, NULL);
-        *ppbImageData = pbImageData = NULL;
-        return FALSE;
-    }
-
-    Try
-    {
-
-        /* initialize the png structure */
-
-#ifdef PNG_STDIO_SUPPORTED
-        png_init_io(png_ptr, pfFile);
-#else
-        png_set_read_fn(png_ptr, (png_voidp)pfFile, png_read_data);
-#endif
-
-        png_set_sig_bytes(png_ptr, 8);
-
-        /* read all PNG info up to image data */
-
-        png_read_info(png_ptr, info_ptr);
-
-        /* get width, height, bit-depth and color-type */
-
-        png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
-            &iColorType, NULL, NULL, NULL);
-
-        /* expand images of all color-type and bit-depth to 3x8-bit RGB */
-        /* let the library process alpha, transparency, background, etc. */
-
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-    if (iBitDepth == 16)
-#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-        png_set_scale_16(png_ptr);
-#  else
-        png_set_strip_16(png_ptr);
-#  endif
-#endif
-        if (iColorType == PNG_COLOR_TYPE_PALETTE)
-            png_set_expand(png_ptr);
-        if (iBitDepth < 8)
-            png_set_expand(png_ptr);
-        if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
-            png_set_expand(png_ptr);
-        if (iColorType == PNG_COLOR_TYPE_GRAY ||
-            iColorType == PNG_COLOR_TYPE_GRAY_ALPHA)
-            png_set_gray_to_rgb(png_ptr);
-
-        /* set the background color to draw transparent and alpha images over */
-        if (png_get_bKGD(png_ptr, info_ptr, &pBackground))
-        {
-            png_set_background(png_ptr, pBackground, PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
-            pBkgColor->red   = (byte) pBackground->red;
-            pBkgColor->green = (byte) pBackground->green;
-            pBkgColor->blue  = (byte) pBackground->blue;
-        }
-        else
-        {
-            pBkgColor = NULL;
-        }
-
-        /* if required set gamma conversion */
-        if (png_get_gAMA(png_ptr, info_ptr, &dGamma))
-            png_set_gamma(png_ptr, (double) 2.2, dGamma);
-
-        /* after the transformations are registered, update info_ptr data */
-
-        png_read_update_info(png_ptr, info_ptr);
-
-        /* get again width, height and the new bit-depth and color-type */
-
-        png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
-            &iColorType, NULL, NULL, NULL);
-
-
-        /* row_bytes is the width x number of channels */
-
-        ulRowBytes = png_get_rowbytes(png_ptr, info_ptr);
-        ulChannels = png_get_channels(png_ptr, info_ptr);
-
-        *piChannels = ulChannels;
-
-        /* now we can allocate memory to store the image */
-
-        if (pbImageData)
-        {
-            free (pbImageData);
-            pbImageData = NULL;
-        }
-        if ((pbImageData = (png_byte *) malloc(ulRowBytes * (*piHeight)
-                            * sizeof(png_byte))) == NULL)
-        {
-            png_error(png_ptr, "Visual PNG: out of memory");
-        }
-        *ppbImageData = pbImageData;
-
-        /* and allocate memory for an array of row-pointers */
-
-        if ((ppbRowPointers = (png_bytepp) malloc((*piHeight)
-                            * sizeof(png_bytep))) == NULL)
-        {
-            png_error(png_ptr, "Visual PNG: out of memory");
-        }
-
-        /* set the individual row-pointers to point at the correct offsets */
-
-        for (i = 0; i < (*piHeight); i++)
-            ppbRowPointers[i] = pbImageData + i * ulRowBytes;
-
-        /* now we can go ahead and just read the whole image */
-
-        png_read_image(png_ptr, ppbRowPointers);
-
-        /* read the additional chunks in the PNG file (not really needed) */
-
-        png_read_end(png_ptr, NULL);
-
-        /* and we're done */
-
-        free (ppbRowPointers);
-        ppbRowPointers = NULL;
-
-        /* yepp, done */
-    }
-
-    Catch (msg)
-    {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-
-        *ppbImageData = pbImageData = NULL;
-
-        if(ppbRowPointers)
-            free (ppbRowPointers);
-
-        fclose(pfFile);
-
-        return FALSE;
-    }
-
-    fclose (pfFile);
-
-    return TRUE;
-}
-
-
-BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
-                   int iWidth, int iHeight, png_color bkgColor)
-{
-    const int           ciBitDepth = 8;
-    const int           ciChannels = 3;
-
-    static FILE        *pfFile;
-    png_uint_32         ulRowBytes;
-    static png_byte   **ppbRowPointers = NULL;
-    int                 i;
-
-    /* open the PNG output file */
-
-    if (!pstrFileName)
-        return FALSE;
-
-    if (!(pfFile = fopen(pstrFileName, "wb")))
-        return FALSE;
-
-    /* prepare the standard PNG structures */
-
-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
-      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
-    if (!png_ptr)
-    {
-        fclose(pfFile);
-        return FALSE;
-    }
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr) {
-        fclose(pfFile);
-        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
-        return FALSE;
-    }
-
-    Try
-    {
-        /* initialize the png structure */
-
-#ifdef PNG_STDIO_SUPPORTED
-        png_init_io(png_ptr, pfFile);
-#else
-        png_set_write_fn(png_ptr, (png_voidp)pfFile, png_write_data, png_flush);
-#endif
-
-        /* we're going to write a very simple 3x8-bit RGB image */
-
-        png_set_IHDR(png_ptr, info_ptr, iWidth, iHeight, ciBitDepth,
-            PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
-            PNG_FILTER_TYPE_BASE);
-
-        /* write the file header information */
-
-        png_write_info(png_ptr, info_ptr);
-
-        /* swap the BGR pixels in the DiData structure to RGB */
-
-        png_set_bgr(png_ptr);
-
-        /* row_bytes is the width x number of channels */
-
-        ulRowBytes = iWidth * ciChannels;
-
-        /* we can allocate memory for an array of row-pointers */
-
-        if ((ppbRowPointers = (png_bytepp) malloc(iHeight * sizeof(png_bytep))) == NULL)
-            Throw "Visualpng: Out of memory";
-
-        /* set the individual row-pointers to point at the correct offsets */
-
-        for (i = 0; i < iHeight; i++)
-            ppbRowPointers[i] = pDiData + i * (((ulRowBytes + 3) >> 2) << 2);
-
-        /* write out the entire image data in one call */
-
-        png_write_image (png_ptr, ppbRowPointers);
-
-        /* write the additional chunks to the PNG file (not really needed) */
-
-        png_write_end(png_ptr, info_ptr);
-
-        /* and we're done */
-
-        free (ppbRowPointers);
-        ppbRowPointers = NULL;
-
-        /* clean up after the write, and free any memory allocated */
-
-        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
-
-        /* yepp, done */
-    }
-
-    Catch (msg)
-    {
-        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
-
-        if(ppbRowPointers)
-            free (ppbRowPointers);
-
-        fclose(pfFile);
-
-        return FALSE;
-    }
-
-    fclose (pfFile);
-
-    return TRUE;
-}
-
-#ifndef PNG_STDIO_SUPPORTED
-
-static void
-png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_size_t check;
-
-   /* fread() returns 0 on error, so it is OK to store this in a png_size_t
-    * instead of an int, which is what fread() actually returns.
-    */
-   check = (png_size_t)fread(data, (png_size_t)1, length,
-      (FILE *)png_ptr->io_ptr);
-
-   if (check != length)
-   {
-      png_error(png_ptr, "Read Error");
-   }
-}
-
-static void
-png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_uint_32 check;
-
-   check = fwrite(data, 1, length, (FILE *)(png_ptr->io_ptr));
-   if (check != length)
-   {
-      png_error(png_ptr, "Write Error");
-   }
-}
-
-static void
-png_flush(png_structp png_ptr)
-{
-   FILE *io_ptr;
-   io_ptr = (FILE *)CVT_PTR((png_ptr->io_ptr));
-   if (io_ptr != NULL)
-      fflush(io_ptr);
-}
-
-#endif
-
-/*-----------------
- *  end of source
- *-----------------
- */
diff --git a/extern/libpng/include/contrib/visupng/PngFile.h b/extern/libpng/include/contrib/visupng/PngFile.h
deleted file mode 100644
index 32181a4eac..0000000000
--- a/extern/libpng/include/contrib/visupng/PngFile.h
+++ /dev/null
@@ -1,30 +0,0 @@
-/*------------------------------------------*/
-/*  PNGFILE.H -- Header File for pngfile.c*/
-/*------------------------------------------*/
-
-/* Copyright 2000, Willem van Schaik.*/
-
-/* This code is released under the libpng license.*/
-/* For conditions of distribution and use, see the disclaimer*/
-/* and license in png.h*/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <windows.h>
-
-void PngFileInitialize (HWND hwnd) ;
-BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;
-BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;
-
-BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData, 
-                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor);
-BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
-                   int iWidth, int iHeight, png_color BkgColor);
-
-#ifndef PNG_STDIO_SUPPORTED
-static void png_read_data(png_structp png_ptr, png_bytep data, png_size_t length);
-static void png_write_data(png_structp png_ptr, png_bytep data, png_size_t length);
-static void png_flush(png_structp png_ptr);
-#endif
-
diff --git a/extern/libpng/include/contrib/visupng/README.txt b/extern/libpng/include/contrib/visupng/README.txt
deleted file mode 100644
index 72c5cba179..0000000000
--- a/extern/libpng/include/contrib/visupng/README.txt
+++ /dev/null
@@ -1,61 +0,0 @@
-Microsoft Developer Studio Build File, Format Version 6.00 for VisualPng
-------------------------------------------------------------------------
-
-Copyright 2000, Willem van Schaik.
-
-This code is released under the libpng license.
-For conditions of distribution and use, see the disclaimer
-and license in png.h
-
-As a PNG .dll demo VisualPng is finished. More features would only hinder
-the program's objective. However, further extensions (like support for other
-graphics formats) are in development. To get these, or for pre-compiled
-binaries, go to "http://www.schaik.com/png/visualpng.html".
-
-------------------------------------------------------------------------
-
-Assumes that
-
-   libpng DLLs and LIBs are in ..\..\projects\msvc\win32\libpng
-   zlib DLLs and LIBs are in   ..\..\projects\msvc\win32\zlib
-   libpng header files are in  ..\..\..\libpng
-   zlib header files are in    ..\..\..\zlib
-   the pngsuite images are in  ..\pngsuite
-
-To build:
-
-1) On the main menu Select "Build|Set Active configuration".
-   Choose the configuration that corresponds to the library you want to test.
-   This library must have been built using the libpng MS project located in
-   the "..\..\mscv" subdirectory.
-
-2) Select "Build|Clean"
-
-3) Select "Build|Rebuild All"
-
-4) After compiling and linking VisualPng will be started to view an image
-   from the PngSuite directory.  Press Ctrl-N (and Ctrl-V) for other images.
-
-
-To install:
-
-When distributing VisualPng (or a further development) the following options
-are available:
-
-1) Build the program with the configuration "Win32 LIB" and you only need to
-   include the executable from the ./lib directory in your distribution.
-
-2) Build the program with the configuration "Win32 DLL" and you need to put
-   in your distribution the executable from the ./dll directory and the dll's
-   libpng1.dll, zlib.dll and msvcrt.dll.  These need to be in the user's PATH.
-
-
-Willem van Schaik
-Calgary, June 6th 2000
-
-P.S. VisualPng was written based on preliminary work of:
-
-    - Simon-Pierre Cadieux
-    - Glenn Randers-Pehrson
-    - Greg Roelofs
-
diff --git a/extern/libpng/include/contrib/visupng/VisualPng.c b/extern/libpng/include/contrib/visupng/VisualPng.c
deleted file mode 100644
index 009f120e35..0000000000
--- a/extern/libpng/include/contrib/visupng/VisualPng.c
+++ /dev/null
@@ -1,969 +0,0 @@
-/*------------------------------------
- *  VisualPng.C -- Shows a PNG image
- *------------------------------------
- *
- * Copyright 2000, Willem van Schaik.
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-/* switches */
-
-/* defines */
-
-#define PROGNAME  "VisualPng"
-#define LONGNAME  "Win32 Viewer for PNG-files"
-#define VERSION   "1.0 of 2000 June 07"
-
-/* constants */
-
-#define MARGIN 8
-
-/* standard includes */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <windows.h>
-
-/* application includes */
-
-#include "png.h"
-#include "pngfile.h"
-#include "resource.h"
-
-/* macros */
-
-/* function prototypes */
-
-LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
-BOOL    CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ;
-
-BOOL CenterAbout (HWND hwndChild, HWND hwndParent);
-
-BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
-        int *pFileIndex);
-
-BOOL SearchPngList (TCHAR *pFileList, int FileCount, int *pFileIndex,
-        PTSTR pstrPrevName, PTSTR pstrNextName);
-
-BOOL LoadImageFile(HWND hwnd, PTSTR pstrPathName,
-        png_byte **ppbImage, int *pxImgSize, int *pyImgSize, int *piChannels,
-        png_color *pBkgColor);
-
-BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
-        BYTE **ppDiData, int cxWinSize, int cyWinSize,
-        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
-        BOOL bStretched);
-
-BOOL InitBitmap (
-        BYTE *pDiData, int cxWinSize, int cyWinSize);
-
-BOOL FillBitmap (
-        BYTE *pDiData, int cxWinSize, int cyWinSize,
-        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
-        BOOL bStretched);
-
-/* a few global variables */
-
-static char *szProgName = PROGNAME;
-static char *szAppName = LONGNAME;
-static char *szIconName = PROGNAME;
-static char szCmdFileName [MAX_PATH];
-
-/* MAIN routine */
-
-int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
-                    PSTR szCmdLine, int iCmdShow)
-{
-    HACCEL   hAccel;
-    HWND     hwnd;
-    MSG      msg;
-    WNDCLASS wndclass;
-    int ixBorders, iyBorders;
-
-    wndclass.style         = CS_HREDRAW | CS_VREDRAW;
-    wndclass.lpfnWndProc   = WndProc;
-    wndclass.cbClsExtra    = 0;
-    wndclass.cbWndExtra    = 0;
-    wndclass.hInstance     = hInstance;
-    wndclass.hIcon         = LoadIcon (hInstance, szIconName) ;
-    wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW);
-    wndclass.hbrBackground = NULL; /* (HBRUSH) GetStockObject (GRAY_BRUSH); */
-    wndclass.lpszMenuName  = szProgName;
-    wndclass.lpszClassName = szProgName;
-
-    if (!RegisterClass (&wndclass))
-    {
-        MessageBox (NULL, TEXT ("Error: this program requires Windows NT!"),
-            szProgName, MB_ICONERROR);
-        return 0;
-    }
-
-    /* if filename given on commandline, store it */
-    if ((szCmdLine != NULL) && (*szCmdLine != '\0'))
-        if (szCmdLine[0] == '"')
-            strncpy (szCmdFileName, szCmdLine + 1, strlen(szCmdLine) - 2);
-        else
-            strcpy (szCmdFileName, szCmdLine);
-    else
-        strcpy (szCmdFileName, "");
-
-    /* calculate size of window-borders */
-    ixBorders = 2 * (GetSystemMetrics (SM_CXBORDER) +
-                     GetSystemMetrics (SM_CXDLGFRAME));
-    iyBorders = 2 * (GetSystemMetrics (SM_CYBORDER) +
-                     GetSystemMetrics (SM_CYDLGFRAME)) +
-                     GetSystemMetrics (SM_CYCAPTION) +
-                     GetSystemMetrics (SM_CYMENUSIZE) +
-                     1; /* WvS: don't ask me why?  */
-
-    hwnd = CreateWindow (szProgName, szAppName,
-        WS_OVERLAPPEDWINDOW,
-        CW_USEDEFAULT, CW_USEDEFAULT,
-        512 + 2 * MARGIN + ixBorders, 384 + 2 * MARGIN + iyBorders,
-/*      CW_USEDEFAULT, CW_USEDEFAULT, */
-        NULL, NULL, hInstance, NULL);
-
-    ShowWindow (hwnd, iCmdShow);
-    UpdateWindow (hwnd);
-
-    hAccel = LoadAccelerators (hInstance, szProgName);
-
-    while (GetMessage (&msg, NULL, 0, 0))
-    {
-        if (!TranslateAccelerator (hwnd, hAccel, &msg))
-        {
-            TranslateMessage (&msg);
-            DispatchMessage (&msg);
-        }
-    }
-    return msg.wParam;
-}
-
-LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,
-        LPARAM lParam)
-{
-    static HINSTANCE          hInstance ;
-    static HDC                hdc;
-    static PAINTSTRUCT        ps;
-    static HMENU              hMenu;
-
-    static BITMAPFILEHEADER  *pbmfh;
-    static BITMAPINFOHEADER  *pbmih;
-    static BYTE              *pbImage;
-    static int                cxWinSize, cyWinSize;
-    static int                cxImgSize, cyImgSize;
-    static int                cImgChannels;
-    static png_color          bkgColor = {127, 127, 127};
-
-    static BOOL               bStretched = TRUE;
-
-    static BYTE              *pDib = NULL;
-    static BYTE              *pDiData = NULL;
-
-    static TCHAR              szImgPathName [MAX_PATH];
-    static TCHAR              szTitleName [MAX_PATH];
-
-    static TCHAR             *pPngFileList = NULL;
-    static int                iPngFileCount;
-    static int                iPngFileIndex;
-
-    BOOL                      bOk;
-
-    switch (message)
-    {
-    case WM_CREATE:
-        hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;
-        PngFileInitialize (hwnd);
-
-        strcpy (szImgPathName, "");
-
-        /* in case we process file given on command-line */
-
-        if (szCmdFileName[0] != '\0')
-        {
-            strcpy (szImgPathName, szCmdFileName);
-
-            /* read the other png-files in the directory for later */
-            /* next/previous commands */
-
-            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
-                          &iPngFileIndex);
-
-            /* load the image from file */
-
-            if (!LoadImageFile (hwnd, szImgPathName,
-                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
-                return 0;
-
-            /* invalidate the client area for later update */
-
-            InvalidateRect (hwnd, NULL, TRUE);
-
-            /* display the PNG into the DIBitmap */
-
-            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
-                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
-        }
-
-        return 0;
-
-    case WM_SIZE:
-        cxWinSize = LOWORD (lParam);
-        cyWinSize = HIWORD (lParam);
-
-        /* invalidate the client area for later update */
-
-        InvalidateRect (hwnd, NULL, TRUE);
-
-        /* display the PNG into the DIBitmap */
-
-        DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
-            pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
-
-        return 0;
-
-    case WM_INITMENUPOPUP:
-        hMenu = GetMenu (hwnd);
-
-        if (pbImage)
-            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_ENABLED);
-        else
-            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_GRAYED);
-
-        return 0;
-
-    case WM_COMMAND:
-        hMenu = GetMenu (hwnd);
-
-        switch (LOWORD (wParam))
-        {
-        case IDM_FILE_OPEN:
-
-            /* show the File Open dialog box */
-
-            if (!PngFileOpenDlg (hwnd, szImgPathName, szTitleName))
-                return 0;
-
-            /* read the other png-files in the directory for later */
-            /* next/previous commands */
-
-            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
-                          &iPngFileIndex);
-
-            /* load the image from file */
-
-            if (!LoadImageFile (hwnd, szImgPathName,
-                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
-                return 0;
-
-            /* invalidate the client area for later update */
-
-            InvalidateRect (hwnd, NULL, TRUE);
-
-            /* display the PNG into the DIBitmap */
-
-            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
-                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
-
-            return 0;
-
-        case IDM_FILE_SAVE:
-
-            /* show the File Save dialog box */
-
-            if (!PngFileSaveDlg (hwnd, szImgPathName, szTitleName))
-                return 0;
-
-            /* save the PNG to a disk file */
-
-            SetCursor (LoadCursor (NULL, IDC_WAIT));
-            ShowCursor (TRUE);
-
-            bOk = PngSaveImage (szImgPathName, pDiData, cxWinSize, cyWinSize,
-                  bkgColor);
-
-            ShowCursor (FALSE);
-            SetCursor (LoadCursor (NULL, IDC_ARROW));
-
-            if (!bOk)
-                MessageBox (hwnd, TEXT ("Error in saving the PNG image"),
-                szProgName, MB_ICONEXCLAMATION | MB_OK);
-            return 0;
-
-        case IDM_FILE_NEXT:
-
-            /* read next entry in the directory */
-
-            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
-                NULL, szImgPathName))
-            {
-                if (strcmp (szImgPathName, "") == 0)
-                    return 0;
-
-                /* load the image from file */
-
-                if (!LoadImageFile (hwnd, szImgPathName, &pbImage,
-                        &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
-                    return 0;
-
-                /* invalidate the client area for later update */
-
-                InvalidateRect (hwnd, NULL, TRUE);
-
-                /* display the PNG into the DIBitmap */
-
-                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
-                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
-            }
-
-            return 0;
-
-        case IDM_FILE_PREVIOUS:
-
-            /* read previous entry in the directory */
-
-            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
-                szImgPathName, NULL))
-            {
-
-                if (strcmp (szImgPathName, "") == 0)
-                    return 0;
-
-                /* load the image from file */
-
-                if (!LoadImageFile (hwnd, szImgPathName, &pbImage, &cxImgSize,
-                    &cyImgSize, &cImgChannels, &bkgColor))
-                    return 0;
-
-                /* invalidate the client area for later update */
-
-                InvalidateRect (hwnd, NULL, TRUE);
-
-                /* display the PNG into the DIBitmap */
-
-                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
-                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
-            }
-
-            return 0;
-
-        case IDM_FILE_EXIT:
-
-            /* more cleanup needed... */
-
-            /* free image buffer */
-
-            if (pDib != NULL)
-            {
-                free (pDib);
-                pDib = NULL;
-            }
-
-            /* free file-list */
-
-            if (pPngFileList != NULL)
-            {
-                free (pPngFileList);
-                pPngFileList = NULL;
-            }
-
-            /* let's go ... */
-
-            exit (0);
-
-            return 0;
-
-        case IDM_OPTIONS_STRETCH:
-            bStretched = !bStretched;
-            if (bStretched)
-                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_CHECKED);
-            else
-                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_UNCHECKED);
-
-            /* invalidate the client area for later update */
-
-            InvalidateRect (hwnd, NULL, TRUE);
-
-            /* display the PNG into the DIBitmap */
-
-            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
-                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
-
-            return 0;
-
-        case IDM_HELP_ABOUT:
-            DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc) ;
-            return 0;
-
-        } /* end switch */
-
-        break;
-
-    case WM_PAINT:
-        hdc = BeginPaint (hwnd, &ps);
-
-        if (pDib)
-            SetDIBitsToDevice (hdc, 0, 0, cxWinSize, cyWinSize, 0, 0,
-                0, cyWinSize, pDiData, (BITMAPINFO *) pDib, DIB_RGB_COLORS);
-
-        EndPaint (hwnd, &ps);
-        return 0;
-
-    case WM_DESTROY:
-        if (pbmfh)
-        {
-            free (pbmfh);
-            pbmfh = NULL;
-        }
-
-        PostQuitMessage (0);
-        return 0;
-    }
-
-    return DefWindowProc (hwnd, message, wParam, lParam);
-}
-
-BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message,
-                            WPARAM wParam, LPARAM lParam)
-{
-     switch (message)
-     {
-     case WM_INITDIALOG :
-          ShowWindow (hDlg, SW_HIDE);
-          CenterAbout (hDlg, GetWindow (hDlg, GW_OWNER));
-          ShowWindow (hDlg, SW_SHOW);
-          return TRUE ;
-
-     case WM_COMMAND :
-          switch (LOWORD (wParam))
-          {
-          case IDOK :
-          case IDCANCEL :
-               EndDialog (hDlg, 0) ;
-               return TRUE ;
-          }
-          break ;
-     }
-     return FALSE ;
-}
-
-/*---------------
- *  CenterAbout
- *---------------
- */
-BOOL CenterAbout (HWND hwndChild, HWND hwndParent)
-{
-   RECT    rChild, rParent, rWorkArea;
-   int     wChild, hChild, wParent, hParent;
-   int     xNew, yNew;
-   BOOL  bResult;
-
-   /* Get the Height and Width of the child window */
-   GetWindowRect (hwndChild, &rChild);
-   wChild = rChild.right - rChild.left;
-   hChild = rChild.bottom - rChild.top;
-
-   /* Get the Height and Width of the parent window */
-   GetWindowRect (hwndParent, &rParent);
-   wParent = rParent.right - rParent.left;
-   hParent = rParent.bottom - rParent.top;
-
-   /* Get the limits of the 'workarea' */
-   bResult = SystemParametersInfo(
-      SPI_GETWORKAREA,  /* system parameter to query or set */
-      sizeof(RECT),
-      &rWorkArea,
-      0);
-   if (!bResult) {
-      rWorkArea.left = rWorkArea.top = 0;
-      rWorkArea.right = GetSystemMetrics(SM_CXSCREEN);
-      rWorkArea.bottom = GetSystemMetrics(SM_CYSCREEN);
-   }
-
-   /* Calculate new X position, then adjust for workarea */
-   xNew = rParent.left + ((wParent - wChild) /2);
-   if (xNew < rWorkArea.left) {
-      xNew = rWorkArea.left;
-   } else if ((xNew+wChild) > rWorkArea.right) {
-      xNew = rWorkArea.right - wChild;
-   }
-
-   /* Calculate new Y position, then adjust for workarea */
-   yNew = rParent.top  + ((hParent - hChild) /2);
-   if (yNew < rWorkArea.top) {
-      yNew = rWorkArea.top;
-   } else if ((yNew+hChild) > rWorkArea.bottom) {
-      yNew = rWorkArea.bottom - hChild;
-   }
-
-   /* Set it, and return */
-   return SetWindowPos (hwndChild, NULL, xNew, yNew, 0, 0, SWP_NOSIZE |
-          SWP_NOZORDER);
-}
-
-/*----------------
- *  BuildPngList
- *----------------
- */
-BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
-     int *pFileIndex)
-{
-    static TCHAR              szImgPathName [MAX_PATH];
-    static TCHAR              szImgFileName [MAX_PATH];
-    static TCHAR              szImgFindName [MAX_PATH];
-
-    WIN32_FIND_DATA           finddata;
-    HANDLE                    hFind;
-
-    static TCHAR              szTmp [MAX_PATH];
-    BOOL                      bOk;
-    int                       i, ii;
-    int                       j, jj;
-
-    /* free previous file-list */
-
-    if (*ppFileList != NULL)
-    {
-        free (*ppFileList);
-        *ppFileList = NULL;
-    }
-
-    /* extract foldername, filename and search-name */
-
-    strcpy (szImgPathName, pstrPathName);
-    strcpy (szImgFileName, strrchr (pstrPathName, '\\') + 1);
-
-    strcpy (szImgFindName, szImgPathName);
-    *(strrchr (szImgFindName, '\\') + 1) = '\0';
-    strcat (szImgFindName, "*.png");
-
-    /* first cycle: count number of files in directory for memory allocation */
-
-    *pFileCount = 0;
-
-    hFind = FindFirstFile(szImgFindName, &finddata);
-    bOk = (hFind != (HANDLE) -1);
-
-    while (bOk)
-    {
-        *pFileCount += 1;
-        bOk = FindNextFile(hFind, &finddata);
-    }
-    FindClose(hFind);
-
-    /* allocation memory for file-list */
-
-    *ppFileList = (TCHAR *) malloc (*pFileCount * MAX_PATH);
-
-    /* second cycle: read directory and store filenames in file-list */
-
-    hFind = FindFirstFile(szImgFindName, &finddata);
-    bOk = (hFind != (HANDLE) -1);
-
-    i = 0;
-    ii = 0;
-    while (bOk)
-    {
-        strcpy (*ppFileList + ii, szImgPathName);
-        strcpy (strrchr(*ppFileList + ii, '\\') + 1, finddata.cFileName);
-
-        if (strcmp(pstrPathName, *ppFileList + ii) == 0)
-            *pFileIndex = i;
-
-        ii += MAX_PATH;
-        i++;
-
-        bOk = FindNextFile(hFind, &finddata);
-    }
-    FindClose(hFind);
-
-    /* finally we must sort the file-list */
-
-    for (i = 0; i < *pFileCount - 1; i++)
-    {
-        ii = i * MAX_PATH;
-        for (j = i+1; j < *pFileCount; j++)
-        {
-            jj = j * MAX_PATH;
-            if (strcmp (*ppFileList + ii, *ppFileList + jj) > 0)
-            {
-                strcpy (szTmp, *ppFileList + jj);
-                strcpy (*ppFileList + jj, *ppFileList + ii);
-                strcpy (*ppFileList + ii, szTmp);
-
-                /* check if this was the current image that we moved */
-
-                if (*pFileIndex == i)
-                    *pFileIndex = j;
-                else
-                    if (*pFileIndex == j)
-                        *pFileIndex = i;
-            }
-        }
-    }
-
-    return TRUE;
-}
-
-/*----------------
- *  SearchPngList
- *----------------
- */
-
-BOOL SearchPngList (
-        TCHAR *pFileList, int FileCount, int *pFileIndex,
-        PTSTR pstrPrevName, PTSTR pstrNextName)
-{
-    if (FileCount > 0)
-    {
-        /* get previous entry */
-
-        if (pstrPrevName != NULL)
-        {
-            if (*pFileIndex > 0)
-                *pFileIndex -= 1;
-            else
-                *pFileIndex = FileCount - 1;
-
-            strcpy (pstrPrevName, pFileList + (*pFileIndex * MAX_PATH));
-        }
-
-        /* get next entry */
-
-        if (pstrNextName != NULL)
-        {
-            if (*pFileIndex < FileCount - 1)
-                *pFileIndex += 1;
-            else
-                *pFileIndex = 0;
-
-            strcpy (pstrNextName, pFileList + (*pFileIndex * MAX_PATH));
-        }
-
-        return TRUE;
-    }
-    else
-    {
-        return FALSE;
-    }
-}
-
-/*-----------------
- *  LoadImageFile
- *-----------------
- */
-
-BOOL LoadImageFile (HWND hwnd, PTSTR pstrPathName,
-                png_byte **ppbImage, int *pxImgSize, int *pyImgSize,
-                int *piChannels, png_color *pBkgColor)
-{
-    static TCHAR szTmp [MAX_PATH];
-
-    /* if there's an existing PNG, free the memory */
-
-    if (*ppbImage)
-    {
-        free (*ppbImage);
-        *ppbImage = NULL;
-    }
-
-    /* Load the entire PNG into memory */
-
-    SetCursor (LoadCursor (NULL, IDC_WAIT));
-    ShowCursor (TRUE);
-
-    PngLoadImage (pstrPathName, ppbImage, pxImgSize, pyImgSize, piChannels,
-                  pBkgColor);
-
-    ShowCursor (FALSE);
-    SetCursor (LoadCursor (NULL, IDC_ARROW));
-
-    if (*ppbImage != NULL)
-    {
-        sprintf (szTmp, "VisualPng - %s", strrchr(pstrPathName, '\\') + 1);
-        SetWindowText (hwnd, szTmp);
-    }
-    else
-    {
-        MessageBox (hwnd, TEXT ("Error in loading the PNG image"),
-            szProgName, MB_ICONEXCLAMATION | MB_OK);
-        return FALSE;
-    }
-
-    return TRUE;
-}
-
-/*----------------
- *  DisplayImage
- *----------------
- */
-BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
-        BYTE **ppDiData, int cxWinSize, int cyWinSize,
-        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
-        BOOL bStretched)
-{
-    BYTE                       *pDib = *ppDib;
-    BYTE                       *pDiData = *ppDiData;
-    /* BITMAPFILEHEADER        *pbmfh; */
-    BITMAPINFOHEADER           *pbmih;
-    WORD                        wDIRowBytes;
-    png_color                   bkgBlack = {0, 0, 0};
-    png_color                   bkgGray  = {127, 127, 127};
-    png_color                   bkgWhite = {255, 255, 255};
-
-    /* allocate memory for the Device Independant bitmap */
-
-    wDIRowBytes = (WORD) ((3 * cxWinSize + 3L) >> 2) << 2;
-
-    if (pDib)
-    {
-        free (pDib);
-        pDib = NULL;
-    }
-
-    if (!(pDib = (BYTE *) malloc (sizeof(BITMAPINFOHEADER) +
-        wDIRowBytes * cyWinSize)))
-    {
-        MessageBox (hwnd, TEXT ("Error in displaying the PNG image"),
-            szProgName, MB_ICONEXCLAMATION | MB_OK);
-        *ppDib = pDib = NULL;
-        return FALSE;
-    }
-    *ppDib = pDib;
-    memset (pDib, 0, sizeof(BITMAPINFOHEADER));
-
-    /* initialize the dib-structure */
-
-    pbmih = (BITMAPINFOHEADER *) pDib;
-    pbmih->biSize = sizeof(BITMAPINFOHEADER);
-    pbmih->biWidth = cxWinSize;
-    pbmih->biHeight = -((long) cyWinSize);
-    pbmih->biPlanes = 1;
-    pbmih->biBitCount = 24;
-    pbmih->biCompression = 0;
-    pDiData = pDib + sizeof(BITMAPINFOHEADER);
-    *ppDiData = pDiData;
-
-    /* first fill bitmap with gray and image border */
-
-    InitBitmap (pDiData, cxWinSize, cyWinSize);
-
-    /* then fill bitmap with image */
-
-    if (pbImage)
-    {
-        FillBitmap (
-            pDiData, cxWinSize, cyWinSize,
-            pbImage, cxImgSize, cyImgSize, cImgChannels,
-            bStretched);
-    }
-
-    return TRUE;
-}
-
-/*--------------
- *  InitBitmap
- *--------------
- */
-BOOL InitBitmap (BYTE *pDiData, int cxWinSize, int cyWinSize)
-{
-    BYTE *dst;
-    int x, y, col;
-
-    /* initialize the background with gray */
-
-    dst = pDiData;
-    for (y = 0; y < cyWinSize; y++)
-    {
-        col = 0;
-        for (x = 0; x < cxWinSize; x++)
-        {
-            /* fill with GRAY */
-            *dst++ = 127;
-            *dst++ = 127;
-            *dst++ = 127;
-            col += 3;
-        }
-        /* rows start on 4 byte boundaries */
-        while ((col % 4) != 0)
-        {
-            dst++;
-            col++;
-        }
-    }
-
-    return TRUE;
-}
-
-/*--------------
- *  FillBitmap
- *--------------
- */
-BOOL FillBitmap (
-        BYTE *pDiData, int cxWinSize, int cyWinSize,
-        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
-        BOOL bStretched)
-{
-    BYTE *pStretchedImage;
-    BYTE *pImg;
-    BYTE *src, *dst;
-    BYTE r, g, b, a;
-    const int cDIChannels = 3;
-    WORD wImgRowBytes;
-    WORD wDIRowBytes;
-    int cxNewSize, cyNewSize;
-    int cxImgPos, cyImgPos;
-    int xImg, yImg;
-    int xWin, yWin;
-    int xOld, yOld;
-    int xNew, yNew;
-
-    if (bStretched)
-    {
-        cxNewSize = cxWinSize - 2 * MARGIN;
-        cyNewSize = cyWinSize - 2 * MARGIN;
-
-        /* stretch the image to it's window determined size */
-
-        /* the following two are mathematically the same, but the first
-         * has side-effects because of rounding
-         */
-/*      if ((cyNewSize / cxNewSize) > (cyImgSize / cxImgSize)) */
-        if ((cyNewSize * cxImgSize) > (cyImgSize * cxNewSize))
-        {
-            cyNewSize = cxNewSize * cyImgSize / cxImgSize;
-            cxImgPos = MARGIN;
-            cyImgPos = (cyWinSize - cyNewSize) / 2;
-        }
-        else
-        {
-            cxNewSize = cyNewSize * cxImgSize / cyImgSize;
-            cyImgPos = MARGIN;
-            cxImgPos = (cxWinSize - cxNewSize) / 2;
-        }
-
-        pStretchedImage = malloc (cImgChannels * cxNewSize * cyNewSize);
-        pImg = pStretchedImage;
-
-        for (yNew = 0; yNew < cyNewSize; yNew++)
-        {
-            yOld = yNew * cyImgSize / cyNewSize;
-            for (xNew = 0; xNew < cxNewSize; xNew++)
-            {
-                xOld = xNew * cxImgSize / cxNewSize;
-
-                r = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 0);
-                g = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 1);
-                b = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 2);
-                *pImg++ = r;
-                *pImg++ = g;
-                *pImg++ = b;
-                if (cImgChannels == 4)
-                {
-                    a = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld)
-                        + 3);
-                    *pImg++ = a;
-                }
-            }
-        }
-
-        /* calculate row-bytes */
-
-        wImgRowBytes = cImgChannels * cxNewSize;
-        wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
-
-        /* copy image to screen */
-
-        for (yImg = 0, yWin = cyImgPos; yImg < cyNewSize; yImg++, yWin++)
-        {
-            if (yWin >= cyWinSize - cyImgPos)
-                break;
-            src = pStretchedImage + yImg * wImgRowBytes;
-            dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
-
-            for (xImg = 0, xWin = cxImgPos; xImg < cxNewSize; xImg++, xWin++)
-            {
-                if (xWin >= cxWinSize - cxImgPos)
-                    break;
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                *dst++ = b; /* note the reverse order  */
-                *dst++ = g;
-                *dst++ = r;
-                if (cImgChannels == 4)
-                {
-                    a = *src++;
-                }
-            }
-        }
-
-        /* free memory */
-
-        if (pStretchedImage != NULL)
-        {
-            free (pStretchedImage);
-            pStretchedImage = NULL;
-        }
-
-    }
-
-    /* process the image not-stretched */
-
-    else
-    {
-        /* calculate the central position */
-
-        cxImgPos = (cxWinSize - cxImgSize) / 2;
-        cyImgPos = (cyWinSize - cyImgSize) / 2;
-
-        /* check for image larger than window */
-
-        if (cxImgPos < MARGIN)
-            cxImgPos = MARGIN;
-        if (cyImgPos < MARGIN)
-            cyImgPos = MARGIN;
-
-        /* calculate both row-bytes */
-
-        wImgRowBytes = cImgChannels * cxImgSize;
-        wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
-
-        /* copy image to screen */
-
-        for (yImg = 0, yWin = cyImgPos; yImg < cyImgSize; yImg++, yWin++)
-        {
-            if (yWin >= cyWinSize - MARGIN)
-                break;
-            src = pbImage + yImg * wImgRowBytes;
-            dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
-
-            for (xImg = 0, xWin = cxImgPos; xImg < cxImgSize; xImg++, xWin++)
-            {
-                if (xWin >= cxWinSize - MARGIN)
-                    break;
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                *dst++ = b; /* note the reverse order  */
-                *dst++ = g;
-                *dst++ = r;
-                if (cImgChannels == 4)
-                {
-                    a = *src++;
-                }
-            }
-        }
-    }
-
-    return TRUE;
-}
-
-/*-----------------
- *  end of source
- *-----------------
- */
diff --git a/extern/libpng/include/contrib/visupng/VisualPng.dsp b/extern/libpng/include/contrib/visupng/VisualPng.dsp
deleted file mode 100644
index 741ef6ce76..0000000000
--- a/extern/libpng/include/contrib/visupng/VisualPng.dsp
+++ /dev/null
@@ -1,147 +0,0 @@
-# Microsoft Developer Studio Project File - Name="VisualPng" - Package Owner=<4>
-# Microsoft Developer Studio Generated Build File, Format Version 6.00
-# ** DO NOT EDIT **
-
-# TARGTYPE "Win32 (x86) Application" 0x0101
-
-CFG=VisualPng - Win32 Debug
-!MESSAGE This is not a valid makefile. To build this project using NMAKE,
-!MESSAGE use the Export Makefile command and run
-!MESSAGE 
-!MESSAGE NMAKE /f "VisualPng.mak".
-!MESSAGE 
-!MESSAGE You can specify a configuration when running NMAKE
-!MESSAGE by defining the macro CFG on the command line. For example:
-!MESSAGE 
-!MESSAGE NMAKE /f "VisualPng.mak" CFG="VisualPng - Win32 Debug"
-!MESSAGE 
-!MESSAGE Possible choices for configuration are:
-!MESSAGE 
-!MESSAGE "VisualPng - Win32 Release" (based on "Win32 (x86) Application")
-!MESSAGE "VisualPng - Win32 Debug" (based on "Win32 (x86) Application")
-!MESSAGE 
-
-# Begin Project
-# PROP AllowPerConfigDependencies 0
-# PROP Scc_ProjName ""
-# PROP Scc_LocalPath ""
-CPP=cl.exe
-MTL=midl.exe
-RSC=rc.exe
-
-!IF  "$(CFG)" == "VisualPng - Win32 Release"
-
-# PROP BASE Use_MFC 0
-# PROP BASE Use_Debug_Libraries 0
-# PROP BASE Output_Dir "Release"
-# PROP BASE Intermediate_Dir "Release"
-# PROP BASE Ignore_Export_Lib 0
-# PROP BASE Target_Dir ""
-# PROP Use_MFC 0
-# PROP Use_Debug_Libraries 0
-# PROP Output_Dir "Release"
-# PROP Intermediate_Dir "Release"
-# PROP Ignore_Export_Lib 0
-# PROP Target_Dir ""
-# ADD BASE CPP /nologo /W3 /O2 /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "NDEBUG" /D "PNG_NO_STDIO" /FD /c
-# SUBTRACT BASE CPP /YX
-# ADD CPP /nologo /MD /W3 /O2 /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "NDEBUG" /D "PNG_NO_STDIO" /FD /c
-# SUBTRACT CPP /YX
-# ADD BASE MTL /nologo /D "NDEBUG" /mktyplib203 /win32
-# ADD MTL /nologo /D "NDEBUG" /mktyplib203 /win32
-# ADD BASE RSC /l 0x409 /d "NDEBUG"
-# ADD RSC /l 0x409 /d "NDEBUG"
-BSC32=bscmake.exe
-# ADD BASE BSC32 /nologo
-# ADD BSC32 /nologo
-LINK32=link.exe
-# ADD BASE LINK32 kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /machine:I386
-# ADD LINK32 ..\..\projects\visualc6\Win32_LIB_Release\libpng.lib ..\..\..\zlib\projects\visualc6\Win32_LIB_Release\zlib.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /machine:I386
-# Begin Special Build Tool
-OutDir=.\Release
-SOURCE="$(InputPath)"
-PostBuild_Cmds=$(outdir)\VisualPng.exe ..\..\contrib\pngsuite\basn6a16.png
-# End Special Build Tool
-
-!ELSEIF  "$(CFG)" == "VisualPng - Win32 Debug"
-
-# PROP BASE Use_MFC 0
-# PROP BASE Use_Debug_Libraries 1
-# PROP BASE Output_Dir "Debug"
-# PROP BASE Intermediate_Dir "Debug"
-# PROP BASE Ignore_Export_Lib 0
-# PROP BASE Target_Dir ""
-# PROP Use_MFC 0
-# PROP Use_Debug_Libraries 1
-# PROP Output_Dir "Debug"
-# PROP Intermediate_Dir "Debug"
-# PROP Ignore_Export_Lib 0
-# PROP Target_Dir ""
-# ADD BASE CPP /nologo /W3 /Gm /ZI /Od /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "_DEBUG" /D "PNG_NO_STDIO" /FD /GZ /c
-# SUBTRACT BASE CPP /YX
-# ADD CPP /nologo /MDd /W3 /Gm /ZI /Od /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "_DEBUG" /D "PNG_NO_STDIO" /FD /GZ /c
-# SUBTRACT CPP /YX
-# ADD BASE MTL /nologo /D "_DEBUG" /mktyplib203 /win32
-# ADD MTL /nologo /D "_DEBUG" /mktyplib203 /win32
-# ADD BASE RSC /l 0x409 /d "_DEBUG"
-# ADD RSC /l 0x409 /d "_DEBUG"
-BSC32=bscmake.exe
-# ADD BASE BSC32 /nologo
-# ADD BSC32 /nologo
-LINK32=link.exe
-# ADD BASE LINK32 kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /debug /machine:I386 /pdbtype:sept
-# ADD LINK32 ..\..\projects\visualc6\Win32_LIB_Release\libpng.lib ..\..\..\zlib\projects\visualc6\Win32_LIB_Release\zlib.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /debug /machine:I386 /nodefaultlib:"msvcrt.lib" /pdbtype:sept
-# Begin Special Build Tool
-OutDir=.\Debug
-SOURCE="$(InputPath)"
-PostBuild_Cmds=$(outdir)\VisualPng.exe ..\..\contrib\pngsuite\basn6a16.png
-# End Special Build Tool
-
-!ENDIF 
-
-# Begin Target
-
-# Name "VisualPng - Win32 Release"
-# Name "VisualPng - Win32 Debug"
-# Begin Group "Source Files"
-
-# PROP Default_Filter "cpp;c;cxx;rc;def;r;odl;idl;hpj;bat"
-# Begin Source File
-
-SOURCE=.\PngFile.c
-# End Source File
-# Begin Source File
-
-SOURCE=.\VisualPng.c
-# End Source File
-# End Group
-# Begin Group "Header Files"
-
-# PROP Default_Filter "h;hpp;hxx;hm;inl"
-# Begin Source File
-
-SOURCE=.\cexcept.h
-# End Source File
-# Begin Source File
-
-SOURCE=.\PngFile.h
-# End Source File
-# Begin Source File
-
-SOURCE=.\resource.h
-# End Source File
-# End Group
-# Begin Group "Resource Files"
-
-# PROP Default_Filter "ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe"
-# Begin Source File
-
-SOURCE=.\VisualPng.ico
-# End Source File
-# Begin Source File
-
-SOURCE=.\VisualPng.rc
-# End Source File
-# End Group
-# End Target
-# End Project
diff --git a/extern/libpng/include/contrib/visupng/VisualPng.dsw b/extern/libpng/include/contrib/visupng/VisualPng.dsw
deleted file mode 100644
index a30e1cc1cd..0000000000
--- a/extern/libpng/include/contrib/visupng/VisualPng.dsw
+++ /dev/null
@@ -1,29 +0,0 @@
-Microsoft Developer Studio Workspace File, Format Version 6.00
-# WARNING: DO NOT EDIT OR DELETE THIS WORKSPACE FILE!
-
-###############################################################################
-
-Project: "VisualPng"=.\VisualPng.dsp - Package Owner=<4>
-
-Package=<5>
-{{{
-}}}
-
-Package=<4>
-{{{
-}}}
-
-###############################################################################
-
-Global:
-
-Package=<5>
-{{{
-}}}
-
-Package=<3>
-{{{
-}}}
-
-###############################################################################
-
diff --git a/extern/libpng/include/contrib/visupng/VisualPng.ico b/extern/libpng/include/contrib/visupng/VisualPng.ico
deleted file mode 100644
index 68aa3719fb523eccd4c4a706e4198ca1be2b4c62..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 766
zcmb_ayGjE=6ul!BJ4Il&5f%%#i;YeE0sqBX?6q(TQ7j^}<v?10VbiXK*cmJrWrHY0
zA!dpc7D2{ycPG(^jp(^^ALqVy29`)b(o_-Sd4*^VeiNEPcc6k+VFA>Bh9<%xts4i6
zkcy&!=Yp>fdCw6P!YMX?g~S3@L(=jS0+)s|N<R6S5r&)Qb!)g04N`MXQq7T*R)b~W
znk>iKlEgL>VOVf)WTfR)85V$RN>JwSV-vWY^X3AQl6o~-A`A21P`H#(L`ua<kb=M>
zC6p2|SPTx|B;lEdR<4J97z(@|!YJx7#d!1r3hTe|MU4Yo<afY7umtC-4d;3T=aM()
z)~BP%-RxmpUOv5)v&rtgAGNEa$M$f0ygxi$8VsbmKHjRzi|)-;zIT4xZ=DSC*L>P<
Ob-aH+fF44>&V2wPTAUpK

diff --git a/extern/libpng/include/contrib/visupng/VisualPng.png b/extern/libpng/include/contrib/visupng/VisualPng.png
deleted file mode 100644
index c6aa80a9bfa275137e429498bc785cb2dbcdb382..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 208
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnL3?x0byx0z;SkfJR9T^xl_H+M9WCils0(?ST
zf%J9`j>RRx2|yNONswPKgTu2MX+Tbfr;B5V#O34!2UcDl9v_~y3Xga?K0NvO<H!Nc
z2bxC$Ry>|~WI+Z?ismL3#z>)ClO+n69&&Pt@)((moHOva6OfZ2FlX_Z0}8s!jvZ1^
zUz2uRL2<>QLkbEXTG%~o9y17?WOH!($Y?g1Vbg3Ozf`fCd_X%HJYD@<);T3K0RUGo
BL5BbU

diff --git a/extern/libpng/include/contrib/visupng/VisualPng.rc b/extern/libpng/include/contrib/visupng/VisualPng.rc
deleted file mode 100644
index 6e0623a73c..0000000000
--- a/extern/libpng/include/contrib/visupng/VisualPng.rc
+++ /dev/null
@@ -1,152 +0,0 @@
-//Microsoft Developer Studio generated resource script.
-//
-#include "resource.h"
-
-#define APSTUDIO_READONLY_SYMBOLS
-/////////////////////////////////////////////////////////////////////////////
-//
-// Generated from the TEXTINCLUDE 2 resource.
-//
-#include "afxres.h"
-
-/////////////////////////////////////////////////////////////////////////////
-#undef APSTUDIO_READONLY_SYMBOLS
-
-/////////////////////////////////////////////////////////////////////////////
-// English (U.S.) resources
-
-#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)
-#ifdef _WIN32
-LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
-#pragma code_page(1252)
-#endif //_WIN32
-
-#ifdef APSTUDIO_INVOKED
-/////////////////////////////////////////////////////////////////////////////
-//
-// TEXTINCLUDE
-//
-
-1 TEXTINCLUDE DISCARDABLE 
-BEGIN
-    "resource.h\0"
-END
-
-2 TEXTINCLUDE DISCARDABLE 
-BEGIN
-    "#include ""afxres.h""\r\n"
-    "\0"
-END
-
-3 TEXTINCLUDE DISCARDABLE 
-BEGIN
-    "\r\n"
-    "\0"
-END
-
-#endif    // APSTUDIO_INVOKED
-
-
-/////////////////////////////////////////////////////////////////////////////
-//
-// Menu
-//
-
-VISUALPNG MENU DISCARDABLE 
-BEGIN
-    POPUP "&File"
-    BEGIN
-        MENUITEM "&Open Image...\tCtrl+O",      IDM_FILE_OPEN
-        MENUITEM "Save &As...",                 IDM_FILE_SAVE
-        MENUITEM SEPARATOR
-        MENUITEM "&Next Image\tCtrl+N",         IDM_FILE_NEXT
-        MENUITEM "Pre&vious Image\tCtrl+V",     IDM_FILE_PREVIOUS
-        MENUITEM SEPARATOR
-        MENUITEM "E&xit\tAlt+X",                IDM_FILE_EXIT
-    END
-    POPUP "&Options"
-    BEGIN
-        MENUITEM "&Stretch",                    IDM_OPTIONS_STRETCH, CHECKED
-    END
-    POPUP "&Help"
-    BEGIN
-        MENUITEM "&About",                      IDM_HELP_ABOUT
-    END
-END
-
-
-/////////////////////////////////////////////////////////////////////////////
-//
-// Accelerator
-//
-
-VISUALPNG ACCELERATORS DISCARDABLE 
-BEGIN
-    "N",            IDM_FILE_NEXT,          VIRTKEY, CONTROL, NOINVERT
-    "O",            IDM_FILE_OPEN,          VIRTKEY, CONTROL, NOINVERT
-    "P",            IDM_FILE_PREVIOUS,      VIRTKEY, CONTROL, NOINVERT
-    "V",            IDM_FILE_PREVIOUS,      VIRTKEY, CONTROL, NOINVERT
-    "X",            IDM_FILE_EXIT,          VIRTKEY, ALT, NOINVERT
-END
-
-
-/////////////////////////////////////////////////////////////////////////////
-//
-// Icon
-//
-
-// Icon with lowest ID value placed first to ensure application icon
-// remains consistent on all systems.
-VISUALPNG               ICON    DISCARDABLE     "VisualPng.ico"
-
-/////////////////////////////////////////////////////////////////////////////
-//
-// Dialog
-//
-
-ABOUTBOX DIALOG DISCARDABLE  0, 0, 186, 94
-STYLE DS_MODALFRAME | WS_POPUP
-FONT 8, "MS Sans Serif"
-BEGIN
-    DEFPUSHBUTTON   "OK",IDOK,68,67,50,14
-    CTEXT           "VisualPng 1.0  -  June 2000",IDC_STATIC,49,14,88,8
-    LTEXT           "a PNG image viewer",IDC_STATIC,60,30,66,8
-    LTEXT           "(c) Willem van Schaik, 2000",IDC_STATIC,48,52,90,8
-    LTEXT           "to demonstrate the use of libpng in Visual C",
-                    IDC_STATIC,25,38,136,8
-END
-
-
-/////////////////////////////////////////////////////////////////////////////
-//
-// DESIGNINFO
-//
-
-#ifdef APSTUDIO_INVOKED
-GUIDELINES DESIGNINFO DISCARDABLE 
-BEGIN
-    "ABOUTBOX", DIALOG
-    BEGIN
-        LEFTMARGIN, 7
-        RIGHTMARGIN, 179
-        TOPMARGIN, 7
-        BOTTOMMARGIN, 87
-    END
-END
-#endif    // APSTUDIO_INVOKED
-
-#endif    // English (U.S.) resources
-/////////////////////////////////////////////////////////////////////////////
-
-
-
-#ifndef APSTUDIO_INVOKED
-/////////////////////////////////////////////////////////////////////////////
-//
-// Generated from the TEXTINCLUDE 3 resource.
-//
-
-
-/////////////////////////////////////////////////////////////////////////////
-#endif    // not APSTUDIO_INVOKED
-
diff --git a/extern/libpng/include/contrib/visupng/cexcept.h b/extern/libpng/include/contrib/visupng/cexcept.h
deleted file mode 100644
index 5f45d76975..0000000000
--- a/extern/libpng/include/contrib/visupng/cexcept.h
+++ /dev/null
@@ -1,248 +0,0 @@
-/*===
-cexcept.h 2.0.1 (2008-Jul-19-Sat)
-http://www.nicemice.net/cexcept/
-Adam M. Costello
-http://www.nicemice.net/amc/
-
-An interface for exception-handling in ANSI C (C89 and subsequent ISO
-standards), developed jointly with Cosmin Truta.
-
-    Copyright (c) 2000-2008 Adam M. Costello and Cosmin Truta.
-    This software may be modified only if its author and version
-    information is updated accurately, and may be redistributed
-    only if accompanied by this unaltered notice.  Subject to those
-    restrictions, permission is granted to anyone to do anything
-    with this software.  The copyright holders make no guarantees
-    regarding this software, and are not responsible for any damage
-    resulting from its use.
-
-The cexcept interface is not compatible with and cannot interact
-with system exceptions (like division by zero or memory segmentation
-violation), compiler-generated exceptions (like C++ exceptions), or
-other exception-handling interfaces.
-
-When using this interface across multiple .c files, do not include
-this header file directly.  Instead, create a wrapper header file that
-includes this header file and then invokes the define_exception_type
-macro (see below).  The .c files should then include that header file.
-
-The interface consists of one type, one well-known name, and six macros.
-
-
-define_exception_type(type_name);
-
-    This macro is used like an external declaration.  It specifies
-    the type of object that gets copied from the exception thrower to
-    the exception catcher.  The type_name can be any type that can be
-    assigned to, that is, a non-constant arithmetic type, struct, union,
-    or pointer.  Examples:
-
-        define_exception_type(int);
-
-        enum exception { out_of_memory, bad_arguments, disk_full };
-        define_exception_type(enum exception);
-
-        struct exception { int code; const char *msg; };
-        define_exception_type(struct exception);
-
-    Because throwing an exception causes the object to be copied (not
-    just once, but twice), programmers may wish to consider size when
-    choosing the exception type.
-
-
-struct exception_context;
-
-    This type may be used after the define_exception_type() macro has
-    been invoked.  A struct exception_context must be known to both
-    the thrower and the catcher.  It is expected that there be one
-    context for each thread that uses exceptions.  It would certainly
-    be dangerous for multiple threads to access the same context.
-    One thread can use multiple contexts, but that is likely to be
-    confusing and not typically useful.  The application can allocate
-    this structure in any way it pleases--automatic, static, or dynamic.
-    The application programmer should pretend not to know the structure
-    members, which are subject to change.
-
-
-struct exception_context *the_exception_context;
-
-    The Try/Catch and Throw statements (described below) implicitly
-    refer to a context, using the name the_exception_context.  It is
-    the application's responsibility to make sure that this name yields
-    the address of a mutable (non-constant) struct exception_context
-    wherever those statements are used.  Subject to that constraint, the
-    application may declare a variable of this name anywhere it likes
-    (inside a function, in a parameter list, or externally), and may
-    use whatever storage class specifiers (static, extern, etc) or type
-    qualifiers (const, volatile, etc) it likes.  Examples:
-
-        static struct exception_context
-          * const the_exception_context = &foo;
-
-        { struct exception_context *the_exception_context = bar; ... }
-
-        int blah(struct exception_context *the_exception_context, ...);
-
-        extern struct exception_context the_exception_context[1];
-
-    The last example illustrates a trick that avoids creating a pointer
-    object separate from the structure object.
-
-    The name could even be a macro, for example:
-
-        struct exception_context ec_array[numthreads];
-        #define the_exception_context (ec_array + thread_id)
-
-    Be aware that the_exception_context is used several times by the
-    Try/Catch/Throw macros, so it shouldn't be expensive or have side
-    effects.  The expansion must be a drop-in replacement for an
-    identifier, so it's safest to put parentheses around it.
-
-
-void init_exception_context(struct exception_context *ec);
-
-    For context structures allocated statically (by an external
-    definition or using the "static" keyword), the implicit
-    initialization to all zeros is sufficient, but contexts allocated
-    by other means must be initialized using this macro before they
-    are used by a Try/Catch statement.  It does no harm to initialize
-    a context more than once (by using this macro on a statically
-    allocated context, or using this macro twice on the same context),
-    but a context must not be re-initialized after it has been used by a
-    Try/Catch statement.
-
-
-Try statement
-Catch (expression) statement
-
-    The Try/Catch/Throw macros are capitalized in order to avoid
-    confusion with the C++ keywords, which have subtly different
-    semantics.
-
-    A Try/Catch statement has a syntax similar to an if/else statement,
-    except that the parenthesized expression goes after the second
-    keyword rather than the first.  As with if/else, there are two
-    clauses, each of which may be a simple statement ending with a
-    semicolon or a brace-enclosed compound statement.  But whereas
-    the else clause is optional, the Catch clause is required.  The
-    expression must be a modifiable lvalue (something capable of being
-    assigned to) of the same type (disregarding type qualifiers) that
-    was passed to define_exception_type().
-
-    If a Throw that uses the same exception context as the Try/Catch is
-    executed within the Try clause (typically within a function called
-    by the Try clause), and the exception is not caught by a nested
-    Try/Catch statement, then a copy of the exception will be assigned
-    to the expression, and control will jump to the Catch clause.  If no
-    such Throw is executed, then the assignment is not performed, and
-    the Catch clause is not executed.
-
-    The expression is not evaluated unless and until the exception is
-    caught, which is significant if it has side effects, for example:
-
-        Try foo();
-        Catch (p[++i].e) { ... }
-
-    IMPORTANT: Jumping into or out of a Try clause (for example via
-    return, break, continue, goto, longjmp) is forbidden--the compiler
-    will not complain, but bad things will happen at run-time.  Jumping
-    into or out of a Catch clause is okay, and so is jumping around
-    inside a Try clause.  In many cases where one is tempted to return
-    from a Try clause, it will suffice to use Throw, and then return
-    from the Catch clause.  Another option is to set a flag variable and
-    use goto to jump to the end of the Try clause, then check the flag
-    after the Try/Catch statement.
-
-    IMPORTANT: The values of any non-volatile automatic variables
-    changed within the Try clause are undefined after an exception is
-    caught.  Therefore, variables modified inside the Try block whose
-    values are needed later outside the Try block must either use static
-    storage or be declared with the "volatile" type qualifier.
-
-
-Throw expression;
-
-    A Throw statement is very much like a return statement, except that
-    the expression is required.  Whereas return jumps back to the place
-    where the current function was called, Throw jumps back to the Catch
-    clause of the innermost enclosing Try clause.  The expression must
-    be compatible with the type passed to define_exception_type().  The
-    exception must be caught, otherwise the program may crash.
-
-    Slight limitation:  If the expression is a comma-expression, it must
-    be enclosed in parentheses.
-
-
-Try statement
-Catch_anonymous statement
-
-    When the value of the exception is not needed, a Try/Catch statement
-    can use Catch_anonymous instead of Catch (expression).
-
-
-Everything below this point is for the benefit of the compiler.  The
-application programmer should pretend not to know any of it, because it
-is subject to change.
-
-===*/
-
-
-#ifndef CEXCEPT_H
-#define CEXCEPT_H
-
-
-#include <setjmp.h>
-
-#define define_exception_type(etype) \
-struct exception_context { \
-  jmp_buf *penv; \
-  int caught; \
-  volatile struct { etype etmp; } v; \
-}
-
-/* etmp must be volatile because the application might use automatic */
-/* storage for the_exception_context, and etmp is modified between   */
-/* the calls to setjmp() and longjmp().  A wrapper struct is used to */
-/* avoid warnings about a duplicate volatile qualifier in case etype */
-/* already includes it.                                              */
-
-#define init_exception_context(ec) ((void)((ec)->penv = 0))
-
-#define Try \
-  { \
-    jmp_buf *exception__prev, exception__env; \
-    exception__prev = the_exception_context->penv; \
-    the_exception_context->penv = &exception__env; \
-    if (setjmp(exception__env) == 0) { \
-      do
-
-#define exception__catch(action) \
-      while (the_exception_context->caught = 0, \
-             the_exception_context->caught); \
-    } \
-    else { \
-      the_exception_context->caught = 1; \
-    } \
-    the_exception_context->penv = exception__prev; \
-  } \
-  if (!the_exception_context->caught || action) { } \
-  else
-
-#define Catch(e) exception__catch(((e) = the_exception_context->v.etmp, 0))
-#define Catch_anonymous exception__catch(0)
-
-/* Try ends with do, and Catch begins with while(0) and ends with     */
-/* else, to ensure that Try/Catch syntax is similar to if/else        */
-/* syntax.                                                            */
-/*                                                                    */
-/* The 0 in while(0) is expressed as x=0,x in order to appease        */
-/* compilers that warn about constant expressions inside while().     */
-/* Most compilers should still recognize that the condition is always */
-/* false and avoid generating code for it.                            */
-
-#define Throw \
-  for (;; longjmp(*the_exception_context->penv, 1)) \
-    the_exception_context->v.etmp =
-
-
-#endif /* CEXCEPT_H */
diff --git a/extern/libpng/include/contrib/visupng/resource.h b/extern/libpng/include/contrib/visupng/resource.h
deleted file mode 100644
index b62176d1dc..0000000000
--- a/extern/libpng/include/contrib/visupng/resource.h
+++ /dev/null
@@ -1,23 +0,0 @@
-//{{NO_DEPENDENCIES}}
-// Microsoft Developer Studio generated include file.
-// Used by VisualPng.rc
-//
-#define IDM_FILE_OPEN                   40001
-#define IDM_FILE_SAVE                   40002
-#define IDM_FILE_NEXT                   40003
-#define IDM_FILE_PREVIOUS               40004
-#define IDM_FILE_EXIT                   40005
-#define IDM_OPTIONS_BACKGROUND          40006
-#define IDM_OPTIONS_STRETCH             40007
-#define IDM_HELP_ABOUT                  40008
-
-// Next default values for new objects
-//
-#ifdef APSTUDIO_INVOKED
-#ifndef APSTUDIO_READONLY_SYMBOLS
-#define _APS_NEXT_RESOURCE_VALUE        113
-#define _APS_NEXT_COMMAND_VALUE         40009
-#define _APS_NEXT_CONTROL_VALUE         1001
-#define _APS_NEXT_SYMED_VALUE           101
-#endif
-#endif
diff --git a/extern/libpng/include/depcomp b/extern/libpng/include/depcomp
deleted file mode 100755
index bd0ac08958..0000000000
--- a/extern/libpng/include/depcomp
+++ /dev/null
@@ -1,688 +0,0 @@
-#! /bin/sh
-# depcomp - compile a program generating dependencies as side-effects
-
-scriptversion=2011-12-04.11; # UTC
-
-# Copyright (C) 1999, 2000, 2003, 2004, 2005, 2006, 2007, 2009, 2010,
-# 2011 Free Software Foundation, Inc.
-
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# As a special exception to the GNU General Public License, if you
-# distribute this file as part of a program that contains a
-# configuration script generated by Autoconf, you may include it under
-# the same distribution terms that you use for the rest of that program.
-
-# Originally written by Alexandre Oliva <oliva@dcc.unicamp.br>.
-
-case $1 in
-  '')
-     echo "$0: No command.  Try \`$0 --help' for more information." 1>&2
-     exit 1;
-     ;;
-  -h | --h*)
-    cat <<\EOF
-Usage: depcomp [--help] [--version] PROGRAM [ARGS]
-
-Run PROGRAMS ARGS to compile a file, generating dependencies
-as side-effects.
-
-Environment variables:
-  depmode     Dependency tracking mode.
-  source      Source file read by `PROGRAMS ARGS'.
-  object      Object file output by `PROGRAMS ARGS'.
-  DEPDIR      directory where to store dependencies.
-  depfile     Dependency file to output.
-  tmpdepfile  Temporary file to use when outputting dependencies.
-  libtool     Whether libtool is used (yes/no).
-
-Report bugs to <bug-automake@gnu.org>.
-EOF
-    exit $?
-    ;;
-  -v | --v*)
-    echo "depcomp $scriptversion"
-    exit $?
-    ;;
-esac
-
-if test -z "$depmode" || test -z "$source" || test -z "$object"; then
-  echo "depcomp: Variables source, object and depmode must be set" 1>&2
-  exit 1
-fi
-
-# Dependencies for sub/bar.o or sub/bar.obj go into sub/.deps/bar.Po.
-depfile=${depfile-`echo "$object" |
-  sed 's|[^\\/]*$|'${DEPDIR-.deps}'/&|;s|\.\([^.]*\)$|.P\1|;s|Pobj$|Po|'`}
-tmpdepfile=${tmpdepfile-`echo "$depfile" | sed 's/\.\([^.]*\)$/.T\1/'`}
-
-rm -f "$tmpdepfile"
-
-# Some modes work just like other modes, but use different flags.  We
-# parameterize here, but still list the modes in the big case below,
-# to make depend.m4 easier to write.  Note that we *cannot* use a case
-# here, because this file can only contain one case statement.
-if test "$depmode" = hp; then
-  # HP compiler uses -M and no extra arg.
-  gccflag=-M
-  depmode=gcc
-fi
-
-if test "$depmode" = dashXmstdout; then
-   # This is just like dashmstdout with a different argument.
-   dashmflag=-xM
-   depmode=dashmstdout
-fi
-
-cygpath_u="cygpath -u -f -"
-if test "$depmode" = msvcmsys; then
-   # This is just like msvisualcpp but w/o cygpath translation.
-   # Just convert the backslash-escaped backslashes to single forward
-   # slashes to satisfy depend.m4
-   cygpath_u='sed s,\\\\,/,g'
-   depmode=msvisualcpp
-fi
-
-if test "$depmode" = msvc7msys; then
-   # This is just like msvc7 but w/o cygpath translation.
-   # Just convert the backslash-escaped backslashes to single forward
-   # slashes to satisfy depend.m4
-   cygpath_u='sed s,\\\\,/,g'
-   depmode=msvc7
-fi
-
-case "$depmode" in
-gcc3)
-## gcc 3 implements dependency tracking that does exactly what
-## we want.  Yay!  Note: for some reason libtool 1.4 doesn't like
-## it if -MD -MP comes after the -MF stuff.  Hmm.
-## Unfortunately, FreeBSD c89 acceptance of flags depends upon
-## the command line argument order; so add the flags where they
-## appear in depend2.am.  Note that the slowdown incurred here
-## affects only configure: in makefiles, %FASTDEP% shortcuts this.
-  for arg
-  do
-    case $arg in
-    -c) set fnord "$@" -MT "$object" -MD -MP -MF "$tmpdepfile" "$arg" ;;
-    *)  set fnord "$@" "$arg" ;;
-    esac
-    shift # fnord
-    shift # $arg
-  done
-  "$@"
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  mv "$tmpdepfile" "$depfile"
-  ;;
-
-gcc)
-## There are various ways to get dependency output from gcc.  Here's
-## why we pick this rather obscure method:
-## - Don't want to use -MD because we'd like the dependencies to end
-##   up in a subdir.  Having to rename by hand is ugly.
-##   (We might end up doing this anyway to support other compilers.)
-## - The DEPENDENCIES_OUTPUT environment variable makes gcc act like
-##   -MM, not -M (despite what the docs say).
-## - Using -M directly means running the compiler twice (even worse
-##   than renaming).
-  if test -z "$gccflag"; then
-    gccflag=-MD,
-  fi
-  "$@" -Wp,"$gccflag$tmpdepfile"
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  rm -f "$depfile"
-  echo "$object : \\" > "$depfile"
-  alpha=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
-## The second -e expression handles DOS-style file names with drive letters.
-  sed -e 's/^[^:]*: / /' \
-      -e 's/^['$alpha']:\/[^:]*: / /' < "$tmpdepfile" >> "$depfile"
-## This next piece of magic avoids the `deleted header file' problem.
-## The problem is that when a header file which appears in a .P file
-## is deleted, the dependency causes make to die (because there is
-## typically no way to rebuild the header).  We avoid this by adding
-## dummy dependencies for each header file.  Too bad gcc doesn't do
-## this for us directly.
-  tr ' ' '
-' < "$tmpdepfile" |
-## Some versions of gcc put a space before the `:'.  On the theory
-## that the space means something, we add a space to the output as
-## well.  hp depmode also adds that space, but also prefixes the VPATH
-## to the object.  Take care to not repeat it in the output.
-## Some versions of the HPUX 10.20 sed can't process this invocation
-## correctly.  Breaking it into two sed invocations is a workaround.
-    sed -e 's/^\\$//' -e '/^$/d' -e "s|.*$object$||" -e '/:$/d' \
-      | sed -e 's/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-hp)
-  # This case exists only to let depend.m4 do its work.  It works by
-  # looking at the text of this script.  This case will never be run,
-  # since it is checked for above.
-  exit 1
-  ;;
-
-sgi)
-  if test "$libtool" = yes; then
-    "$@" "-Wp,-MDupdate,$tmpdepfile"
-  else
-    "$@" -MDupdate "$tmpdepfile"
-  fi
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  rm -f "$depfile"
-
-  if test -f "$tmpdepfile"; then  # yes, the sourcefile depend on other files
-    echo "$object : \\" > "$depfile"
-
-    # Clip off the initial element (the dependent).  Don't try to be
-    # clever and replace this with sed code, as IRIX sed won't handle
-    # lines with more than a fixed number of characters (4096 in
-    # IRIX 6.2 sed, 8192 in IRIX 6.5).  We also remove comment lines;
-    # the IRIX cc adds comments like `#:fec' to the end of the
-    # dependency line.
-    tr ' ' '
-' < "$tmpdepfile" \
-    | sed -e 's/^.*\.o://' -e 's/#.*$//' -e '/^$/ d' | \
-    tr '
-' ' ' >> "$depfile"
-    echo >> "$depfile"
-
-    # The second pass generates a dummy entry for each header file.
-    tr ' ' '
-' < "$tmpdepfile" \
-   | sed -e 's/^.*\.o://' -e 's/#.*$//' -e '/^$/ d' -e 's/$/:/' \
-   >> "$depfile"
-  else
-    # The sourcefile does not contain any dependencies, so just
-    # store a dummy comment line, to avoid errors with the Makefile
-    # "include basename.Plo" scheme.
-    echo "#dummy" > "$depfile"
-  fi
-  rm -f "$tmpdepfile"
-  ;;
-
-aix)
-  # The C for AIX Compiler uses -M and outputs the dependencies
-  # in a .u file.  In older versions, this file always lives in the
-  # current directory.  Also, the AIX compiler puts `$object:' at the
-  # start of each line; $object doesn't have directory information.
-  # Version 6 uses the directory in both cases.
-  dir=`echo "$object" | sed -e 's|/[^/]*$|/|'`
-  test "x$dir" = "x$object" && dir=
-  base=`echo "$object" | sed -e 's|^.*/||' -e 's/\.o$//' -e 's/\.lo$//'`
-  if test "$libtool" = yes; then
-    tmpdepfile1=$dir$base.u
-    tmpdepfile2=$base.u
-    tmpdepfile3=$dir.libs/$base.u
-    "$@" -Wc,-M
-  else
-    tmpdepfile1=$dir$base.u
-    tmpdepfile2=$dir$base.u
-    tmpdepfile3=$dir$base.u
-    "$@" -M
-  fi
-  stat=$?
-
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
-    exit $stat
-  fi
-
-  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
-  do
-    test -f "$tmpdepfile" && break
-  done
-  if test -f "$tmpdepfile"; then
-    # Each line is of the form `foo.o: dependent.h'.
-    # Do two passes, one to just change these to
-    # `$object: dependent.h' and one to simply `dependent.h:'.
-    sed -e "s,^.*\.[a-z]*:,$object:," < "$tmpdepfile" > "$depfile"
-    # That's a tab and a space in the [].
-    sed -e 's,^.*\.[a-z]*:[	 ]*,,' -e 's,$,:,' < "$tmpdepfile" >> "$depfile"
-  else
-    # The sourcefile does not contain any dependencies, so just
-    # store a dummy comment line, to avoid errors with the Makefile
-    # "include basename.Plo" scheme.
-    echo "#dummy" > "$depfile"
-  fi
-  rm -f "$tmpdepfile"
-  ;;
-
-icc)
-  # Intel's C compiler understands `-MD -MF file'.  However on
-  #    icc -MD -MF foo.d -c -o sub/foo.o sub/foo.c
-  # ICC 7.0 will fill foo.d with something like
-  #    foo.o: sub/foo.c
-  #    foo.o: sub/foo.h
-  # which is wrong.  We want:
-  #    sub/foo.o: sub/foo.c
-  #    sub/foo.o: sub/foo.h
-  #    sub/foo.c:
-  #    sub/foo.h:
-  # ICC 7.1 will output
-  #    foo.o: sub/foo.c sub/foo.h
-  # and will wrap long lines using \ :
-  #    foo.o: sub/foo.c ... \
-  #     sub/foo.h ... \
-  #     ...
-
-  "$@" -MD -MF "$tmpdepfile"
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  rm -f "$depfile"
-  # Each line is of the form `foo.o: dependent.h',
-  # or `foo.o: dep1.h dep2.h \', or ` dep3.h dep4.h \'.
-  # Do two passes, one to just change these to
-  # `$object: dependent.h' and one to simply `dependent.h:'.
-  sed "s,^[^:]*:,$object :," < "$tmpdepfile" > "$depfile"
-  # Some versions of the HPUX 10.20 sed can't process this invocation
-  # correctly.  Breaking it into two sed invocations is a workaround.
-  sed 's,^[^:]*: \(.*\)$,\1,;s/^\\$//;/^$/d;/:$/d' < "$tmpdepfile" |
-    sed -e 's/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-hp2)
-  # The "hp" stanza above does not work with aCC (C++) and HP's ia64
-  # compilers, which have integrated preprocessors.  The correct option
-  # to use with these is +Maked; it writes dependencies to a file named
-  # 'foo.d', which lands next to the object file, wherever that
-  # happens to be.
-  # Much of this is similar to the tru64 case; see comments there.
-  dir=`echo "$object" | sed -e 's|/[^/]*$|/|'`
-  test "x$dir" = "x$object" && dir=
-  base=`echo "$object" | sed -e 's|^.*/||' -e 's/\.o$//' -e 's/\.lo$//'`
-  if test "$libtool" = yes; then
-    tmpdepfile1=$dir$base.d
-    tmpdepfile2=$dir.libs/$base.d
-    "$@" -Wc,+Maked
-  else
-    tmpdepfile1=$dir$base.d
-    tmpdepfile2=$dir$base.d
-    "$@" +Maked
-  fi
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-     rm -f "$tmpdepfile1" "$tmpdepfile2"
-     exit $stat
-  fi
-
-  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2"
-  do
-    test -f "$tmpdepfile" && break
-  done
-  if test -f "$tmpdepfile"; then
-    sed -e "s,^.*\.[a-z]*:,$object:," "$tmpdepfile" > "$depfile"
-    # Add `dependent.h:' lines.
-    sed -ne '2,${
-	       s/^ *//
-	       s/ \\*$//
-	       s/$/:/
-	       p
-	     }' "$tmpdepfile" >> "$depfile"
-  else
-    echo "#dummy" > "$depfile"
-  fi
-  rm -f "$tmpdepfile" "$tmpdepfile2"
-  ;;
-
-tru64)
-   # The Tru64 compiler uses -MD to generate dependencies as a side
-   # effect.  `cc -MD -o foo.o ...' puts the dependencies into `foo.o.d'.
-   # At least on Alpha/Redhat 6.1, Compaq CCC V6.2-504 seems to put
-   # dependencies in `foo.d' instead, so we check for that too.
-   # Subdirectories are respected.
-   dir=`echo "$object" | sed -e 's|/[^/]*$|/|'`
-   test "x$dir" = "x$object" && dir=
-   base=`echo "$object" | sed -e 's|^.*/||' -e 's/\.o$//' -e 's/\.lo$//'`
-
-   if test "$libtool" = yes; then
-      # With Tru64 cc, shared objects can also be used to make a
-      # static library.  This mechanism is used in libtool 1.4 series to
-      # handle both shared and static libraries in a single compilation.
-      # With libtool 1.4, dependencies were output in $dir.libs/$base.lo.d.
-      #
-      # With libtool 1.5 this exception was removed, and libtool now
-      # generates 2 separate objects for the 2 libraries.  These two
-      # compilations output dependencies in $dir.libs/$base.o.d and
-      # in $dir$base.o.d.  We have to check for both files, because
-      # one of the two compilations can be disabled.  We should prefer
-      # $dir$base.o.d over $dir.libs/$base.o.d because the latter is
-      # automatically cleaned when .libs/ is deleted, while ignoring
-      # the former would cause a distcleancheck panic.
-      tmpdepfile1=$dir.libs/$base.lo.d   # libtool 1.4
-      tmpdepfile2=$dir$base.o.d          # libtool 1.5
-      tmpdepfile3=$dir.libs/$base.o.d    # libtool 1.5
-      tmpdepfile4=$dir.libs/$base.d      # Compaq CCC V6.2-504
-      "$@" -Wc,-MD
-   else
-      tmpdepfile1=$dir$base.o.d
-      tmpdepfile2=$dir$base.d
-      tmpdepfile3=$dir$base.d
-      tmpdepfile4=$dir$base.d
-      "$@" -MD
-   fi
-
-   stat=$?
-   if test $stat -eq 0; then :
-   else
-      rm -f "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3" "$tmpdepfile4"
-      exit $stat
-   fi
-
-   for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3" "$tmpdepfile4"
-   do
-     test -f "$tmpdepfile" && break
-   done
-   if test -f "$tmpdepfile"; then
-      sed -e "s,^.*\.[a-z]*:,$object:," < "$tmpdepfile" > "$depfile"
-      # That's a tab and a space in the [].
-      sed -e 's,^.*\.[a-z]*:[	 ]*,,' -e 's,$,:,' < "$tmpdepfile" >> "$depfile"
-   else
-      echo "#dummy" > "$depfile"
-   fi
-   rm -f "$tmpdepfile"
-   ;;
-
-msvc7)
-  if test "$libtool" = yes; then
-    showIncludes=-Wc,-showIncludes
-  else
-    showIncludes=-showIncludes
-  fi
-  "$@" $showIncludes > "$tmpdepfile"
-  stat=$?
-  grep -v '^Note: including file: ' "$tmpdepfile"
-  if test "$stat" = 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  rm -f "$depfile"
-  echo "$object : \\" > "$depfile"
-  # The first sed program below extracts the file names and escapes
-  # backslashes for cygpath.  The second sed program outputs the file
-  # name when reading, but also accumulates all include files in the
-  # hold buffer in order to output them again at the end.  This only
-  # works with sed implementations that can handle large buffers.
-  sed < "$tmpdepfile" -n '
-/^Note: including file:  *\(.*\)/ {
-  s//\1/
-  s/\\/\\\\/g
-  p
-}' | $cygpath_u | sort -u | sed -n '
-s/ /\\ /g
-s/\(.*\)/	\1 \\/p
-s/.\(.*\) \\/\1:/
-H
-$ {
-  s/.*/	/
-  G
-  p
-}' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-msvc7msys)
-  # This case exists only to let depend.m4 do its work.  It works by
-  # looking at the text of this script.  This case will never be run,
-  # since it is checked for above.
-  exit 1
-  ;;
-
-#nosideeffect)
-  # This comment above is used by automake to tell side-effect
-  # dependency tracking mechanisms from slower ones.
-
-dashmstdout)
-  # Important note: in order to support this mode, a compiler *must*
-  # always write the preprocessed file to stdout, regardless of -o.
-  "$@" || exit $?
-
-  # Remove the call to Libtool.
-  if test "$libtool" = yes; then
-    while test "X$1" != 'X--mode=compile'; do
-      shift
-    done
-    shift
-  fi
-
-  # Remove `-o $object'.
-  IFS=" "
-  for arg
-  do
-    case $arg in
-    -o)
-      shift
-      ;;
-    $object)
-      shift
-      ;;
-    *)
-      set fnord "$@" "$arg"
-      shift # fnord
-      shift # $arg
-      ;;
-    esac
-  done
-
-  test -z "$dashmflag" && dashmflag=-M
-  # Require at least two characters before searching for `:'
-  # in the target name.  This is to cope with DOS-style filenames:
-  # a dependency such as `c:/foo/bar' could be seen as target `c' otherwise.
-  "$@" $dashmflag |
-    sed 's:^[  ]*[^: ][^:][^:]*\:[    ]*:'"$object"'\: :' > "$tmpdepfile"
-  rm -f "$depfile"
-  cat < "$tmpdepfile" > "$depfile"
-  tr ' ' '
-' < "$tmpdepfile" | \
-## Some versions of the HPUX 10.20 sed can't process this invocation
-## correctly.  Breaking it into two sed invocations is a workaround.
-    sed -e 's/^\\$//' -e '/^$/d' -e '/:$/d' | sed -e 's/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-dashXmstdout)
-  # This case only exists to satisfy depend.m4.  It is never actually
-  # run, as this mode is specially recognized in the preamble.
-  exit 1
-  ;;
-
-makedepend)
-  "$@" || exit $?
-  # Remove any Libtool call
-  if test "$libtool" = yes; then
-    while test "X$1" != 'X--mode=compile'; do
-      shift
-    done
-    shift
-  fi
-  # X makedepend
-  shift
-  cleared=no eat=no
-  for arg
-  do
-    case $cleared in
-    no)
-      set ""; shift
-      cleared=yes ;;
-    esac
-    if test $eat = yes; then
-      eat=no
-      continue
-    fi
-    case "$arg" in
-    -D*|-I*)
-      set fnord "$@" "$arg"; shift ;;
-    # Strip any option that makedepend may not understand.  Remove
-    # the object too, otherwise makedepend will parse it as a source file.
-    -arch)
-      eat=yes ;;
-    -*|$object)
-      ;;
-    *)
-      set fnord "$@" "$arg"; shift ;;
-    esac
-  done
-  obj_suffix=`echo "$object" | sed 's/^.*\././'`
-  touch "$tmpdepfile"
-  ${MAKEDEPEND-makedepend} -o"$obj_suffix" -f"$tmpdepfile" "$@"
-  rm -f "$depfile"
-  # makedepend may prepend the VPATH from the source file name to the object.
-  # No need to regex-escape $object, excess matching of '.' is harmless.
-  sed "s|^.*\($object *:\)|\1|" "$tmpdepfile" > "$depfile"
-  sed '1,2d' "$tmpdepfile" | tr ' ' '
-' | \
-## Some versions of the HPUX 10.20 sed can't process this invocation
-## correctly.  Breaking it into two sed invocations is a workaround.
-    sed -e 's/^\\$//' -e '/^$/d' -e '/:$/d' | sed -e 's/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile" "$tmpdepfile".bak
-  ;;
-
-cpp)
-  # Important note: in order to support this mode, a compiler *must*
-  # always write the preprocessed file to stdout.
-  "$@" || exit $?
-
-  # Remove the call to Libtool.
-  if test "$libtool" = yes; then
-    while test "X$1" != 'X--mode=compile'; do
-      shift
-    done
-    shift
-  fi
-
-  # Remove `-o $object'.
-  IFS=" "
-  for arg
-  do
-    case $arg in
-    -o)
-      shift
-      ;;
-    $object)
-      shift
-      ;;
-    *)
-      set fnord "$@" "$arg"
-      shift # fnord
-      shift # $arg
-      ;;
-    esac
-  done
-
-  "$@" -E |
-    sed -n -e '/^# [0-9][0-9]* "\([^"]*\)".*/ s:: \1 \\:p' \
-       -e '/^#line [0-9][0-9]* "\([^"]*\)".*/ s:: \1 \\:p' |
-    sed '$ s: \\$::' > "$tmpdepfile"
-  rm -f "$depfile"
-  echo "$object : \\" > "$depfile"
-  cat < "$tmpdepfile" >> "$depfile"
-  sed < "$tmpdepfile" '/^$/d;s/^ //;s/ \\$//;s/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-msvisualcpp)
-  # Important note: in order to support this mode, a compiler *must*
-  # always write the preprocessed file to stdout.
-  "$@" || exit $?
-
-  # Remove the call to Libtool.
-  if test "$libtool" = yes; then
-    while test "X$1" != 'X--mode=compile'; do
-      shift
-    done
-    shift
-  fi
-
-  IFS=" "
-  for arg
-  do
-    case "$arg" in
-    -o)
-      shift
-      ;;
-    $object)
-      shift
-      ;;
-    "-Gm"|"/Gm"|"-Gi"|"/Gi"|"-ZI"|"/ZI")
-	set fnord "$@"
-	shift
-	shift
-	;;
-    *)
-	set fnord "$@" "$arg"
-	shift
-	shift
-	;;
-    esac
-  done
-  "$@" -E 2>/dev/null |
-  sed -n '/^#line [0-9][0-9]* "\([^"]*\)"/ s::\1:p' | $cygpath_u | sort -u > "$tmpdepfile"
-  rm -f "$depfile"
-  echo "$object : \\" > "$depfile"
-  sed < "$tmpdepfile" -n -e 's% %\\ %g' -e '/^\(.*\)$/ s::	\1 \\:p' >> "$depfile"
-  echo "	" >> "$depfile"
-  sed < "$tmpdepfile" -n -e 's% %\\ %g' -e '/^\(.*\)$/ s::\1\::p' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-msvcmsys)
-  # This case exists only to let depend.m4 do its work.  It works by
-  # looking at the text of this script.  This case will never be run,
-  # since it is checked for above.
-  exit 1
-  ;;
-
-none)
-  exec "$@"
-  ;;
-
-*)
-  echo "Unknown depmode $depmode" 1>&2
-  exit 1
-  ;;
-esac
-
-exit 0
-
-# Local Variables:
-# mode: shell-script
-# sh-indentation: 2
-# eval: (add-hook 'write-file-hooks 'time-stamp)
-# time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
-# time-stamp-time-zone: "UTC"
-# time-stamp-end: "; # UTC"
-# End:
diff --git a/extern/libpng/include/example.c b/extern/libpng/include/example.c
deleted file mode 100644
index c20d86b154..0000000000
--- a/extern/libpng/include/example.c
+++ /dev/null
@@ -1,875 +0,0 @@
-
-#if 0 /* in case someone actually tries to compile this */
-
-/* example.c - an example of using libpng
- * Last changed in libpng 1.5.10 [March 8, 2012]
- * Maintained 1998-2012 Glenn Randers-Pehrson
- * Maintained 1996, 1997 Andreas Dilger
- * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
- */
-
-/* This is an example of how to use libpng to read and write PNG files.
- * The file libpng-manual.txt is much more verbose then this.  If you have not
- * read it, do so first.  This was designed to be a starting point of an
- * implementation.  This is not officially part of libpng, is hereby placed
- * in the public domain, and therefore does not require a copyright notice.
- * To the extent possible under law, the authors have waived all copyright and
- * related or neighboring rights to this file.
- *
- * This file does not currently compile, because it is missing certain
- * parts, like allocating memory to hold an image.  You will have to
- * supply these parts to get it to compile.  For an example of a minimal
- * working PNG reader/writer, see pngtest.c, included in this distribution;
- * see also the programs in the contrib directory.
- */
-
-#define _POSIX_SOURCE 1  /* libpng and zlib are POSIX-compliant.  You may
-                          * change this if your application uses non-POSIX
-                          * extensions. */
-
-#include "png.h"
-
- /* The png_jmpbuf() macro, used in error handling, became available in
-  * libpng version 1.0.6.  If you want to be able to run your code with older
-  * versions of libpng, you must define the macro yourself (but only if it
-  * is not already defined by libpng!).
-  */
-
-#ifndef png_jmpbuf
-#  define png_jmpbuf(png_ptr) ((png_ptr)->png_jmpbuf)
-#endif
-
-/* Check to see if a file is a PNG file using png_sig_cmp().  png_sig_cmp()
- * returns zero if the image is a PNG and nonzero if it isn't a PNG.
- *
- * The function check_if_png() shown here, but not used, returns nonzero (true)
- * if the file can be opened and is a PNG, 0 (false) otherwise.
- *
- * If this call is successful, and you are going to keep the file open,
- * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
- * you have created the png_ptr, so that libpng knows your application
- * has read that many bytes from the start of the file.  Make sure you
- * don't call png_set_sig_bytes() with more than 8 bytes read or give it
- * an incorrect number of bytes read, or you will either have read too
- * many bytes (your fault), or you are telling libpng to read the wrong
- * number of magic bytes (also your fault).
- *
- * Many applications already read the first 2 or 4 bytes from the start
- * of the image to determine the file type, so it would be easiest just
- * to pass the bytes to png_sig_cmp() or even skip that if you know
- * you have a PNG file, and call png_set_sig_bytes().
- */
-#define PNG_BYTES_TO_CHECK 4
-int check_if_png(char *file_name, FILE **fp)
-{
-   char buf[PNG_BYTES_TO_CHECK];
-
-   /* Open the prospective PNG file. */
-   if ((*fp = fopen(file_name, "rb")) == NULL)
-      return 0;
-
-   /* Read in some of the signature bytes */
-   if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK)
-      return 0;
-
-   /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
-      Return nonzero (true) if they match */
-
-   return(!png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK));
-}
-
-/* Read a PNG file.  You may want to return an error code if the read
- * fails (depending upon the failure).  There are two "prototypes" given
- * here - one where we are given the filename, and we need to open the
- * file, and the other where we are given an open file (possibly with
- * some or all of the magic bytes read - see comments above).
- */
-#ifdef open_file /* prototype 1 */
-void read_png(char *file_name)  /* We need to open the file */
-{
-   png_structp png_ptr;
-   png_infop info_ptr;
-   unsigned int sig_read = 0;
-   png_uint_32 width, height;
-   int bit_depth, color_type, interlace_type;
-   FILE *fp;
-
-   if ((fp = fopen(file_name, "rb")) == NULL)
-      return (ERROR);
-
-#else no_open_file /* prototype 2 */
-void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
-{
-   png_structp png_ptr;
-   png_infop info_ptr;
-   png_uint_32 width, height;
-   int bit_depth, color_type, interlace_type;
-#endif no_open_file /* Only use one prototype! */
-
-   /* Create and initialize the png_struct with the desired error handler
-    * functions.  If you want to use the default stderr and longjump method,
-    * you can supply NULL for the last three parameters.  We also supply the
-    * the compiler header file version, so that we know if the application
-    * was compiled with a compatible version of the library.  REQUIRED
-    */
-   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
-      png_voidp user_error_ptr, user_error_fn, user_warning_fn);
-
-   if (png_ptr == NULL)
-   {
-      fclose(fp);
-      return (ERROR);
-   }
-
-   /* Allocate/initialize the memory for image information.  REQUIRED. */
-   info_ptr = png_create_info_struct(png_ptr);
-   if (info_ptr == NULL)
-   {
-      fclose(fp);
-      png_destroy_read_struct(&png_ptr, NULL, NULL);
-      return (ERROR);
-   }
-
-   /* Set error handling if you are using the setjmp/longjmp method (this is
-    * the normal method of doing things with libpng).  REQUIRED unless you
-    * set up your own error handlers in the png_create_read_struct() earlier.
-    */
-
-   if (setjmp(png_jmpbuf(png_ptr)))
-   {
-      /* Free all of the memory associated with the png_ptr and info_ptr */
-      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-      fclose(fp);
-      /* If we get here, we had a problem reading the file */
-      return (ERROR);
-   }
-
-   /* One of the following I/O initialization methods is REQUIRED */
-#ifdef streams /* PNG file I/O method 1 */
-   /* Set up the input control if you are using standard C streams */
-   png_init_io(png_ptr, fp);
-
-#else no_streams /* PNG file I/O method 2 */
-   /* If you are using replacement read functions, instead of calling
-    * png_init_io() here you would call:
-    */
-   png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
-   /* where user_io_ptr is a structure you want available to the callbacks */
-#endif no_streams /* Use only one I/O method! */
-
-   /* If we have already read some of the signature */
-   png_set_sig_bytes(png_ptr, sig_read);
-
-#ifdef hilevel
-   /*
-    * If you have enough memory to read in the entire image at once,
-    * and you need to specify only transforms that can be controlled
-    * with one of the PNG_TRANSFORM_* bits (this presently excludes
-    * quantizing, filling, setting background, and doing gamma
-    * adjustment), then you can read the entire image (including
-    * pixels) into the info structure with this call:
-    */
-   png_read_png(png_ptr, info_ptr, png_transforms, NULL);
-
-#else
-   /* OK, you're doing it the hard way, with the lower-level functions */
-
-   /* The call to png_read_info() gives us all of the information from the
-    * PNG file before the first IDAT (image data chunk).  REQUIRED
-    */
-   png_read_info(png_ptr, info_ptr);
-
-   png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
-       &interlace_type, NULL, NULL);
-
-   /* Set up the data transformations you want.  Note that these are all
-    * optional.  Only call them if you want/need them.  Many of the
-    * transformations only work on specific types of images, and many
-    * are mutually exclusive.
-    */
-
-   /* Tell libpng to strip 16 bit/color files down to 8 bits/color.
-    * Use accurate scaling if it's available, otherwise just chop off the
-    * low byte.
-    */
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-    png_set_scale_16(png_ptr);
-#else
-   png_set_strip_16(png_ptr);
-#endif
-
-   /* Strip alpha bytes from the input data without combining with the
-    * background (not recommended).
-    */
-   png_set_strip_alpha(png_ptr);
-
-   /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
-    * byte into separate bytes (useful for paletted and grayscale images).
-    */
-   png_set_packing(png_ptr);
-
-   /* Change the order of packed pixels to least significant bit first
-    * (not useful if you are using png_set_packing). */
-   png_set_packswap(png_ptr);
-
-   /* Expand paletted colors into true RGB triplets */
-   if (color_type == PNG_COLOR_TYPE_PALETTE)
-      png_set_palette_to_rgb(png_ptr);
-
-   /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
-   if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
-      png_set_expand_gray_1_2_4_to_8(png_ptr);
-
-   /* Expand paletted or RGB images with transparency to full alpha channels
-    * so the data will be available as RGBA quartets.
-    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
-      png_set_tRNS_to_alpha(png_ptr);
-
-   /* Set the background color to draw transparent and alpha images over.
-    * It is possible to set the red, green, and blue components directly
-    * for paletted images instead of supplying a palette index.  Note that
-    * even if the PNG file supplies a background, you are not required to
-    * use it - you should use the (solid) application background if it has one.
-    */
-
-   png_color_16 my_background, *image_background;
-
-   if (png_get_bKGD(png_ptr, info_ptr, &image_background))
-      png_set_background(png_ptr, image_background,
-                         PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
-   else
-      png_set_background(png_ptr, &my_background,
-                         PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
-
-   /* Some suggestions as to how to get a screen gamma value
-    *
-    * Note that screen gamma is the display_exponent, which includes
-    * the CRT_exponent and any correction for viewing conditions
-    */
-   if (/* We have a user-defined screen gamma value */)
-   {
-      screen_gamma = user-defined screen_gamma;
-   }
-   /* This is one way that applications share the same screen gamma value */
-   else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL)
-   {
-      screen_gamma = atof(gamma_str);
-   }
-   /* If we don't have another value */
-   else
-   {
-      screen_gamma = 2.2;  /* A good guess for a PC monitor in a dimly
-                              lit room */
-      screen_gamma = 1.7 or 1.0;  /* A good guess for Mac systems */
-   }
-
-   /* Tell libpng to handle the gamma conversion for you.  The final call
-    * is a good guess for PC generated images, but it should be configurable
-    * by the user at run time by the user.  It is strongly suggested that
-    * your application support gamma correction.
-    */
-
-   int intent;
-
-   if (png_get_sRGB(png_ptr, info_ptr, &intent))
-      png_set_gamma(png_ptr, screen_gamma, 0.45455);
-   else
-   {
-      double image_gamma;
-      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
-         png_set_gamma(png_ptr, screen_gamma, image_gamma);
-      else
-         png_set_gamma(png_ptr, screen_gamma, 0.45455);
-   }
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-   /* Quantize RGB files down to 8 bit palette or reduce palettes
-    * to the number of colors available on your screen.
-    */
-   if (color_type & PNG_COLOR_MASK_COLOR)
-   {
-      int num_palette;
-      png_colorp palette;
-
-      /* This reduces the image to the application supplied palette */
-      if (/* We have our own palette */)
-      {
-         /* An array of colors to which the image should be quantized */
-         png_color std_color_cube[MAX_SCREEN_COLORS];
-
-         png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
-            MAX_SCREEN_COLORS, NULL, 0);
-      }
-      /* This reduces the image to the palette supplied in the file */
-      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
-      {
-         png_uint_16p histogram = NULL;
-
-         png_get_hIST(png_ptr, info_ptr, &histogram);
-
-         png_set_quantize(png_ptr, palette, num_palette,
-                        max_screen_colors, histogram, 0);
-      }
-   }
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
-
-   /* Invert monochrome files to have 0 as white and 1 as black */
-   png_set_invert_mono(png_ptr);
-
-   /* If you want to shift the pixel values from the range [0,255] or
-    * [0,65535] to the original [0,7] or [0,31], or whatever range the
-    * colors were originally in:
-    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
-   {
-      png_color_8p sig_bit_p;
-
-      png_get_sBIT(png_ptr, info_ptr, &sig_bit_p);
-      png_set_shift(png_ptr, sig_bit_p);
-   }
-
-   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
-   if (color_type & PNG_COLOR_MASK_COLOR)
-      png_set_bgr(png_ptr);
-
-   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
-   png_set_swap_alpha(png_ptr);
-
-   /* Swap bytes of 16 bit files to least significant byte first */
-   png_set_swap(png_ptr);
-
-   /* Add filler (or alpha) byte (before/after each RGB triplet) */
-   png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Turn on interlace handling.  REQUIRED if you are not using
-    * png_read_image().  To see how to handle interlacing passes,
-    * see the png_read_row() method below:
-    */
-   number_passes = png_set_interlace_handling(png_ptr);
-#else
-   number_passes = 1;
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-
-
-   /* Optional call to gamma correct and add the background to the palette
-    * and update info structure.  REQUIRED if you are expecting libpng to
-    * update the palette for you (ie you selected such a transform above).
-    */
-   png_read_update_info(png_ptr, info_ptr);
-
-   /* Allocate the memory to hold the image using the fields of info_ptr. */
-
-   /* The easiest way to read the image: */
-   png_bytep row_pointers[height];
-
-   /* Clear the pointer array */
-   for (row = 0; row < height; row++)
-      row_pointers[row] = NULL;
-
-   for (row = 0; row < height; row++)
-      row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
-         info_ptr));
-
-   /* Now it's time to read the image.  One of these methods is REQUIRED */
-#ifdef entire /* Read the entire image in one go */
-   png_read_image(png_ptr, row_pointers);
-
-#else no_entire /* Read the image one or more scanlines at a time */
-   /* The other way to read images - deal with interlacing: */
-
-   for (pass = 0; pass < number_passes; pass++)
-   {
-#ifdef single /* Read the image a single row at a time */
-      for (y = 0; y < height; y++)
-      {
-         png_read_rows(png_ptr, &row_pointers[y], NULL, 1);
-      }
-
-#else no_single /* Read the image several rows at a time */
-      for (y = 0; y < height; y += number_of_rows)
-      {
-#ifdef sparkle /* Read the image using the "sparkle" effect. */
-         png_read_rows(png_ptr, &row_pointers[y], NULL,
-            number_of_rows);
-#else no_sparkle /* Read the image using the "rectangle" effect */
-         png_read_rows(png_ptr, NULL, &row_pointers[y],
-            number_of_rows);
-#endif no_sparkle /* Use only one of these two methods */
-      }
-
-      /* If you want to display the image after every pass, do so here */
-#endif no_single /* Use only one of these two methods */
-   }
-#endif no_entire /* Use only one of these two methods */
-
-   /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
-   png_read_end(png_ptr, info_ptr);
-#endif hilevel
-
-   /* At this point you have read the entire image */
-
-   /* Clean up after the read, and free any memory allocated - REQUIRED */
-   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-
-   /* Close the file */
-   fclose(fp);
-
-   /* That's it */
-   return (OK);
-}
-
-/* Progressively read a file */
-
-int
-initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
-{
-   /* Create and initialize the png_struct with the desired error handler
-    * functions.  If you want to use the default stderr and longjump method,
-    * you can supply NULL for the last three parameters.  We also check that
-    * the library version is compatible in case we are using dynamically
-    * linked libraries.
-    */
-   *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
-       png_voidp user_error_ptr, user_error_fn, user_warning_fn);
-
-   if (*png_ptr == NULL)
-   {
-      *info_ptr = NULL;
-      return (ERROR);
-   }
-
-   *info_ptr = png_create_info_struct(png_ptr);
-
-   if (*info_ptr == NULL)
-   {
-      png_destroy_read_struct(png_ptr, info_ptr, NULL);
-      return (ERROR);
-   }
-
-   if (setjmp(png_jmpbuf((*png_ptr))))
-   {
-      png_destroy_read_struct(png_ptr, info_ptr, NULL);
-      return (ERROR);
-   }
-
-   /* This one's new.  You will need to provide all three
-    * function callbacks, even if you aren't using them all.
-    * If you aren't using all functions, you can specify NULL
-    * parameters.  Even when all three functions are NULL,
-    * you need to call png_set_progressive_read_fn().
-    * These functions shouldn't be dependent on global or
-    * static variables if you are decoding several images
-    * simultaneously.  You should store stream specific data
-    * in a separate struct, given as the second parameter,
-    * and retrieve the pointer from inside the callbacks using
-    * the function png_get_progressive_ptr(png_ptr).
-    */
-   png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
-      info_callback, row_callback, end_callback);
-
-   return (OK);
-}
-
-int
-process_data(png_structp *png_ptr, png_infop *info_ptr,
-   png_bytep buffer, png_uint_32 length)
-{
-   if (setjmp(png_jmpbuf((*png_ptr))))
-   {
-      /* Free the png_ptr and info_ptr memory on error */
-      png_destroy_read_struct(png_ptr, info_ptr, NULL);
-      return (ERROR);
-   }
-
-   /* This one's new also.  Simply give it chunks of data as
-    * they arrive from the data stream (in order, of course).
-    * On segmented machines, don't give it any more than 64K.
-    * The library seems to run fine with sizes of 4K, although
-    * you can give it much less if necessary (I assume you can
-    * give it chunks of 1 byte, but I haven't tried with less
-    * than 256 bytes yet).  When this function returns, you may
-    * want to display any rows that were generated in the row
-    * callback, if you aren't already displaying them there.
-    */
-   png_process_data(*png_ptr, *info_ptr, buffer, length);
-   return (OK);
-}
-
-info_callback(png_structp png_ptr, png_infop info)
-{
-   /* Do any setup here, including setting any of the transformations
-    * mentioned in the Reading PNG files section.  For now, you _must_
-    * call either png_start_read_image() or png_read_update_info()
-    * after all the transformations are set (even if you don't set
-    * any).  You may start getting rows before png_process_data()
-    * returns, so this is your last chance to prepare for that.
-    */
-}
-
-row_callback(png_structp png_ptr, png_bytep new_row,
-   png_uint_32 row_num, int pass)
-{
-   /*
-    * This function is called for every row in the image.  If the
-    * image is interlaced, and you turned on the interlace handler,
-    * this function will be called for every row in every pass.
-    *
-    * In this function you will receive a pointer to new row data from
-    * libpng called new_row that is to replace a corresponding row (of
-    * the same data format) in a buffer allocated by your application.
-    *
-    * The new row data pointer "new_row" may be NULL, indicating there is
-    * no new data to be replaced (in cases of interlace loading).
-    *
-    * If new_row is not NULL then you need to call
-    * png_progressive_combine_row() to replace the corresponding row as
-    * shown below:
-    */
-
-   /* Get pointer to corresponding row in our
-    * PNG read buffer.
-    */
-   png_bytep old_row = ((png_bytep *)our_data)[row_num];
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* If both rows are allocated then copy the new row
-    * data to the corresponding row data.
-    */
-   if ((old_row != NULL) && (new_row != NULL))
-   png_progressive_combine_row(png_ptr, old_row, new_row);
-
-   /*
-    * The rows and passes are called in order, so you don't really
-    * need the row_num and pass, but I'm supplying them because it
-    * may make your life easier.
-    *
-    * For the non-NULL rows of interlaced images, you must call
-    * png_progressive_combine_row() passing in the new row and the
-    * old row, as demonstrated above.  You can call this function for
-    * NULL rows (it will just return) and for non-interlaced images
-    * (it just does the png_memcpy for you) if it will make the code
-    * easier.  Thus, you can just do this for all cases:
-    */
-
-   png_progressive_combine_row(png_ptr, old_row, new_row);
-
-   /* where old_row is what was displayed for previous rows.  Note
-    * that the first pass (pass == 0 really) will completely cover
-    * the old row, so the rows do not have to be initialized.  After
-    * the first pass (and only for interlaced images), you will have
-    * to pass the current row as new_row, and the function will combine
-    * the old row and the new row.
-    */
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-}
-
-end_callback(png_structp png_ptr, png_infop info)
-{
-   /* This function is called when the whole image has been read,
-    * including any chunks after the image (up to and including
-    * the IEND).  You will usually have the same info chunk as you
-    * had in the header, although some data may have been added
-    * to the comments and time fields.
-    *
-    * Most people won't do much here, perhaps setting a flag that
-    * marks the image as finished.
-    */
-}
-
-/* Write a png file */
-void write_png(char *file_name /* , ... other image information ... */)
-{
-   FILE *fp;
-   png_structp png_ptr;
-   png_infop info_ptr;
-   png_colorp palette;
-
-   /* Open the file */
-   fp = fopen(file_name, "wb");
-   if (fp == NULL)
-      return (ERROR);
-
-   /* Create and initialize the png_struct with the desired error handler
-    * functions.  If you want to use the default stderr and longjump method,
-    * you can supply NULL for the last three parameters.  We also check that
-    * the library version is compatible with the one used at compile time,
-    * in case we are using dynamically linked libraries.  REQUIRED.
-    */
-   png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
-      png_voidp user_error_ptr, user_error_fn, user_warning_fn);
-
-   if (png_ptr == NULL)
-   {
-      fclose(fp);
-      return (ERROR);
-   }
-
-   /* Allocate/initialize the image information data.  REQUIRED */
-   info_ptr = png_create_info_struct(png_ptr);
-   if (info_ptr == NULL)
-   {
-      fclose(fp);
-      png_destroy_write_struct(&png_ptr,  NULL);
-      return (ERROR);
-   }
-
-   /* Set error handling.  REQUIRED if you aren't supplying your own
-    * error handling functions in the png_create_write_struct() call.
-    */
-   if (setjmp(png_jmpbuf(png_ptr)))
-   {
-      /* If we get here, we had a problem writing the file */
-      fclose(fp);
-      png_destroy_write_struct(&png_ptr, &info_ptr);
-      return (ERROR);
-   }
-
-   /* One of the following I/O initialization functions is REQUIRED */
-
-#ifdef streams /* I/O initialization method 1 */
-   /* Set up the output control if you are using standard C streams */
-   png_init_io(png_ptr, fp);
-
-#else no_streams /* I/O initialization method 2 */
-   /* If you are using replacement write functions, instead of calling
-    * png_init_io() here you would call
-    */
-   png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
-      user_IO_flush_function);
-   /* where user_io_ptr is a structure you want available to the callbacks */
-#endif no_streams /* Only use one initialization method */
-
-#ifdef hilevel
-   /* This is the easy way.  Use it if you already have all the
-    * image info living in the structure.  You could "|" many
-    * PNG_TRANSFORM flags into the png_transforms integer here.
-    */
-   png_write_png(png_ptr, info_ptr, png_transforms, NULL);
-
-#else
-   /* This is the hard way */
-
-   /* Set the image information here.  Width and height are up to 2^31,
-    * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
-    * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,
-    * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB,
-    * or PNG_COLOR_TYPE_RGB_ALPHA.  interlace is either PNG_INTERLACE_NONE or
-    * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST
-    * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED
-    */
-   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, PNG_COLOR_TYPE_???,
-      PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
-   /* Set the palette if there is one.  REQUIRED for indexed-color images */
-   palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH
-             * png_sizeof(png_color));
-   /* ... Set palette colors ... */
-   png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH);
-   /* You must not free palette here, because png_set_PLTE only makes a link to
-    * the palette that you malloced.  Wait until you are about to destroy
-    * the png structure.
-    */
-
-   /* Optional significant bit (sBIT) chunk */
-   png_color_8 sig_bit;
-
-   /* If we are dealing with a grayscale image then */
-   sig_bit.gray = true_bit_depth;
-
-   /* Otherwise, if we are dealing with a color image then */
-   sig_bit.red = true_red_bit_depth;
-   sig_bit.green = true_green_bit_depth;
-   sig_bit.blue = true_blue_bit_depth;
-
-   /* If the image has an alpha channel then */
-   sig_bit.alpha = true_alpha_bit_depth;
-
-   png_set_sBIT(png_ptr, info_ptr, &sig_bit);
-
-
-   /* Optional gamma chunk is strongly suggested if you have any guess
-    * as to the correct gamma of the image.
-    */
-   png_set_gAMA(png_ptr, info_ptr, gamma);
-
-   /* Optionally write comments into the image */
-   {
-      png_text text_ptr[3];
-
-      char key0[]="Title";
-      char text0[]="Mona Lisa";
-      text_ptr[0].key = key0;
-      text_ptr[0].text = text0;
-      text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
-      text_ptr[0].itxt_length = 0;
-      text_ptr[0].lang = NULL;
-      text_ptr[0].lang_key = NULL;
-
-      char key1[]="Author";
-      char text1[]="Leonardo DaVinci";
-      text_ptr[1].key = key1;
-      text_ptr[1].text = text1;
-      text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
-      text_ptr[1].itxt_length = 0;
-      text_ptr[1].lang = NULL;
-      text_ptr[1].lang_key = NULL;
-
-      char key2[]="Description";
-      char text2[]="<long text>";
-      text_ptr[2].key = key2;
-      text_ptr[2].text = text2;
-      text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
-      text_ptr[2].itxt_length = 0;
-      text_ptr[2].lang = NULL;
-      text_ptr[2].lang_key = NULL;
-
-      png_set_text(write_ptr, write_info_ptr, text_ptr, 3);
-   }
-
-   /* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs */
-
-   /* Note that if sRGB is present the gAMA and cHRM chunks must be ignored
-    * on read and, if your application chooses to write them, they must
-    * be written in accordance with the sRGB profile
-    */
-
-   /* Write the file header information.  REQUIRED */
-   png_write_info(png_ptr, info_ptr);
-
-   /* If you want, you can write the info in two steps, in case you need to
-    * write your private chunk ahead of PLTE:
-    *
-    *   png_write_info_before_PLTE(write_ptr, write_info_ptr);
-    *   write_my_chunk();
-    *   png_write_info(png_ptr, info_ptr);
-    *
-    * However, given the level of known- and unknown-chunk support in 1.2.0
-    * and up, this should no longer be necessary.
-    */
-
-   /* Once we write out the header, the compression type on the text
-    * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
-    * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
-    * at the end.
-    */
-
-   /* Set up the transformations you want.  Note that these are
-    * all optional.  Only call them if you want them.
-    */
-
-   /* Invert monochrome pixels */
-   png_set_invert_mono(png_ptr);
-
-   /* Shift the pixels up to a legal bit depth and fill in
-    * as appropriate to correctly scale the image.
-    */
-   png_set_shift(png_ptr, &sig_bit);
-
-   /* Pack pixels into bytes */
-   png_set_packing(png_ptr);
-
-   /* Swap location of alpha bytes from ARGB to RGBA */
-   png_set_swap_alpha(png_ptr);
-
-   /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
-    * RGB (4 channels -> 3 channels). The second parameter is not used.
-    */
-   png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
-
-   /* Flip BGR pixels to RGB */
-   png_set_bgr(png_ptr);
-
-   /* Swap bytes of 16-bit files to most significant byte first */
-   png_set_swap(png_ptr);
-
-   /* Swap bits of 1, 2, 4 bit packed pixel formats */
-   png_set_packswap(png_ptr);
-
-   /* Turn on interlace handling if you are not using png_write_image() */
-   if (interlacing)
-      number_passes = png_set_interlace_handling(png_ptr);
-
-   else
-      number_passes = 1;
-
-   /* The easiest way to write the image (you may have a different memory
-    * layout, however, so choose what fits your needs best).  You need to
-    * use the first method if you aren't handling interlacing yourself.
-    */
-   png_uint_32 k, height, width;
-   png_byte image[height][width*bytes_per_pixel];
-   png_bytep row_pointers[height];
-
-   if (height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
-     png_error (png_ptr, "Image is too tall to process in memory");
-
-   for (k = 0; k < height; k++)
-     row_pointers[k] = image + k*width*bytes_per_pixel;
-
-   /* One of the following output methods is REQUIRED */
-
-#ifdef entire /* Write out the entire image data in one call */
-   png_write_image(png_ptr, row_pointers);
-
-   /* The other way to write the image - deal with interlacing */
-
-#else no_entire /* Write out the image data by one or more scanlines */
-
-   /* The number of passes is either 1 for non-interlaced images,
-    * or 7 for interlaced images.
-    */
-   for (pass = 0; pass < number_passes; pass++)
-   {
-      /* Write a few rows at a time. */
-      png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows);
-
-      /* If you are only writing one row at a time, this works */
-      for (y = 0; y < height; y++)
-         png_write_rows(png_ptr, &row_pointers[y], 1);
-   }
-#endif no_entire /* Use only one output method */
-
-   /* You can write optional chunks like tEXt, zTXt, and tIME at the end
-    * as well.  Shouldn't be necessary in 1.2.0 and up as all the public
-    * chunks are supported and you can use png_set_unknown_chunks() to
-    * register unknown chunks into the info structure to be written out.
-    */
-
-   /* It is REQUIRED to call this to finish writing the rest of the file */
-   png_write_end(png_ptr, info_ptr);
-#endif hilevel
-
-   /* If you png_malloced a palette, free it here (don't free info_ptr->palette,
-    * as recommended in versions 1.0.5m and earlier of this example; if
-    * libpng mallocs info_ptr->palette, libpng will free it).  If you
-    * allocated it with malloc() instead of png_malloc(), use free() instead
-    * of png_free().
-    */
-   png_free(png_ptr, palette);
-   palette = NULL;
-
-   /* Similarly, if you png_malloced any data that you passed in with
-    * png_set_something(), such as a hist or trans array, free it here,
-    * when you can be sure that libpng is through with it.
-    */
-   png_free(png_ptr, trans);
-   trans = NULL;
-   /* Whenever you use png_free() it is a good idea to set the pointer to
-    * NULL in case your application inadvertently tries to png_free() it
-    * again.  When png_free() sees a NULL it returns without action, thus
-    * avoiding the double-free security problem.
-    */
-
-   /* Clean up after the write, and free any memory allocated */
-   png_destroy_write_struct(&png_ptr, &info_ptr);
-
-   /* Close the file */
-   fclose(fp);
-
-   /* That's it */
-   return (OK);
-}
-
-#endif /* if 0 */
diff --git a/extern/libpng/include/libpng-config.in b/extern/libpng/include/libpng-config.in
deleted file mode 100755
index 69bf8e33f0..0000000000
--- a/extern/libpng/include/libpng-config.in
+++ /dev/null
@@ -1,127 +0,0 @@
-#! /bin/sh
-
-# libpng-config
-# provides configuration info for libpng.
-
-# Copyright (C) 2002, 2004, 2006, 2007 Glenn Randers-Pehrson
-
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Modeled after libxml-config.
-
-version="@PNGLIB_VERSION@"
-prefix="@prefix@"
-exec_prefix="@exec_prefix@"
-libdir="@libdir@"
-includedir="@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
-libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
-all_libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ @LIBS@"
-I_opts="-I${includedir}"
-L_opts="-L${libdir}"
-R_opts=""
-cppflags=""
-ccopts=""
-ldopts=""
-
-usage()
-{
-    cat <<EOF
-Usage: $0 [OPTION] ...
-
-Known values for OPTION are:
-
-  --prefix        print libpng prefix
-  --libdir        print path to directory containing library
-  --libs          print library linking information
-  --ccopts        print compiler options
-  --cppflags      print pre-processor flags
-  --cflags        print preprocessor flags, I_opts, and compiler options
-  --I_opts        print "-I" include options
-  --L_opts        print linker "-L" flags for dynamic linking
-  --R_opts        print dynamic linker "-R" or "-rpath" flags
-  --ldopts        print linker options
-  --ldflags       print linker flags (ldopts, L_opts, R_opts, and libs)
-  --static        revise subsequent outputs for static linking
-  --help          print this help and exit
-  --version       print version information
-EOF
-
-    exit $1
-}
-
-if test $# -eq 0; then
-    usage 1
-fi
-
-while test $# -gt 0; do
-    case "$1" in
-
-    --prefix)
-        echo ${prefix}
-        ;;
-
-    --version)
-        echo ${version}
-        exit 0
-        ;;
-
-    --help)
-        usage 0
-        ;;
-
-    --ccopts)
-        echo ${ccopts}
-        ;;
-
-    --cppflags)
-        echo ${cppflags}
-        ;;
-
-    --cflags)
-        echo ${I_opts} ${cppflags} ${ccopts}
-        ;;
-
-    --libdir)
-        echo ${libdir}
-        ;;
-
-    --libs)
-        echo ${libs}
-        ;;
-
-    --I_opts)
-        echo ${I_opts}
-        ;;
-
-    --L_opts)
-        echo ${L_opts}
-        ;;
-
-    --R_opts)
-        echo ${R_opts}
-        ;;
-
-    --ldopts)
-        echo ${ldopts}
-        ;;
-
-    --ldflags)
-        echo ${ldopts} ${L_opts} ${R_opts} ${libs}
-        ;;
-
-    --static)
-        R_opts=""
-        libs=${all_libs}
-        ;;
-
-    *)
-        usage
-        exit 1
-        ;;
-    esac
-    shift
-done
-
-exit 0
diff --git a/extern/libpng/include/libpng-manual.txt b/extern/libpng/include/libpng-manual.txt
deleted file mode 100644
index d55e80a009..0000000000
--- a/extern/libpng/include/libpng-manual.txt
+++ /dev/null
@@ -1,4652 +0,0 @@
-libpng-manual.txt - A description on how to use and modify libpng
-
- libpng version 1.5.10 - March 29, 2012
- Updated and distributed by Glenn Randers-Pehrson
- <glennrp at users.sourceforge.net>
- Copyright (c) 1998-2011 Glenn Randers-Pehrson
-
- This document is released under the libpng license.
- For conditions of distribution and use, see the disclaimer
- and license in png.h
-
- Based on:
-
- libpng versions 0.97, January 1998, through 1.5.10 - March 29, 2012
- Updated and distributed by Glenn Randers-Pehrson
- Copyright (c) 1998-2011 Glenn Randers-Pehrson
-
- libpng 1.0 beta 6  version 0.96 May 28, 1997
- Updated and distributed by Andreas Dilger
- Copyright (c) 1996, 1997 Andreas Dilger
-
- libpng 1.0 beta 2 - version 0.88  January 26, 1996
- For conditions of distribution and use, see copyright
- notice in png.h. Copyright (c) 1995, 1996 Guy Eric
- Schalnat, Group 42, Inc.
-
- Updated/rewritten per request in the libpng FAQ
- Copyright (c) 1995, 1996 Frank J. T. Wojcik
- December 18, 1995 & January 20, 1996
-
-I. Introduction
-
-This file describes how to use and modify the PNG reference library
-(known as libpng) for your own use.  There are five sections to this
-file: introduction, structures, reading, writing, and modification and
-configuration notes for various special platforms.  In addition to this
-file, example.c is a good starting point for using the library, as
-it is heavily commented and should include everything most people
-will need.  We assume that libpng is already installed; see the
-INSTALL file for instructions on how to install libpng.
-
-For examples of libpng usage, see the files "example.c", "pngtest.c",
-and the files in the "contrib" directory, all of which are included in
-the libpng distribution.
-
-Libpng was written as a companion to the PNG specification, as a way
-of reducing the amount of time and effort it takes to support the PNG
-file format in application programs.
-
-The PNG specification (second edition), November 2003, is available as
-a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2003 (E)) at
-<http://www.w3.org/TR/2003/REC-PNG-20031110/
-The W3C and ISO documents have identical technical content.
-
-The PNG-1.2 specification is available at
-<http://www.libpng.org/pub/png/documents/>.  It is technically equivalent
-to the PNG specification (second edition) but has some additional material.
-
-The PNG-1.0 specification is available
-as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a
-W3C Recommendation <http://www.w3.org/TR/REC.png.html>.
-
-Some additional chunks are described in the special-purpose public chunks
-documents at <http://www.libpng.org/pub/png/documents/>.
-
-Other information
-about PNG, and the latest version of libpng, can be found at the PNG home
-page, <http://www.libpng.org/pub/png/>.
-
-Most users will not have to modify the library significantly; advanced
-users may want to modify it more.  All attempts were made to make it as
-complete as possible, while keeping the code easy to understand.
-Currently, this library only supports C.  Support for other languages
-is being considered.
-
-Libpng has been designed to handle multiple sessions at one time,
-to be easily modifiable, to be portable to the vast majority of
-machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
-to use.  The ultimate goal of libpng is to promote the acceptance of
-the PNG file format in whatever way possible.  While there is still
-work to be done (see the TODO file), libpng should cover the
-majority of the needs of its users.
-
-Libpng uses zlib for its compression and decompression of PNG files.
-Further information about zlib, and the latest version of zlib, can
-be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>.
-The zlib compression utility is a general purpose utility that is
-useful for more than PNG files, and can be used without libpng.
-See the documentation delivered with zlib for more details.
-You can usually find the source files for the zlib utility wherever you
-find the libpng source files.
-
-Libpng is thread safe, provided the threads are using different
-instances of the structures.  Each thread should have its own
-png_struct and png_info instances, and thus its own image.
-Libpng does not protect itself against two threads using the
-same instance of a structure.
-
-II. Structures
-
-There are two main structures that are important to libpng, png_struct
-and png_info.  Both are internal structures that are no longer exposed
-in the libpng interface (as of libpng 1.5.0).
-
-The png_info structure is designed to provide information about the
-PNG file.  At one time, the fields of png_info were intended to be
-directly accessible to the user.  However, this tended to cause problems
-with applications using dynamically loaded libraries, and as a result
-a set of interface functions for png_info (the png_get_*() and png_set_*()
-functions) was developed, and direct access to the png_info fields was
-deprecated..
-
-The png_struct structure is the object used by the library to decode a
-single image.  As of 1.5.0 this structure is also not exposed.
-
-Almost all libpng APIs require a pointer to a png_struct as the first argument.
-Many (in particular the png_set and png_get APIs) also require a pointer
-to png_info as the second argument.  Some application visible macros
-defined in png.h designed for basic data access (reading and writing
-integers in the PNG format) don't take a png_info pointer, but it's almost
-always safe to assume that a (png_struct*) has to be passed to call an API
-function.
-
-You can have more than one png_info structure associated with an image,
-as illustrated in pngtest.c, one for information valid prior to the
-IDAT chunks and another (called "end_info" below) for things after them.
-
-The png.h header file is an invaluable reference for programming with libpng.
-And while I'm on the topic, make sure you include the libpng header file:
-
-#include <png.h>
-
-and also (as of libpng-1.5.0) the zlib header file, if you need it:
-
-#include <zlib.h>
-
-Types
-
-The png.h header file defines a number of integral types used by the
-APIs.  Most of these are fairly obvious; for example types corresponding
-to integers of particular sizes and types for passing color values.
-
-One exception is how non-integral numbers are handled.  For application
-convenience most APIs that take such numbers have C (double) arguments,
-however internally PNG, and libpng, use 32 bit signed integers and encode
-the value by multiplying by 100,000.  As of libpng 1.5.0 a convenience
-macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
-which is simply (png_int_32).
-
-All APIs that take (double) arguments also have a matching API that
-takes the corresponding fixed point integer arguments.  The fixed point
-API has the same name as the floating point one with "_fixed" appended.
-The actual range of values permitted in the APIs is frequently less than
-the full range of (png_fixed_point) (-21474 to +21474).  When APIs require
-a non-negative argument the type is recorded as png_uint_32 above.  Consult
-the header file and the text below for more information.
-
-Special care must be take with sCAL chunk handling because the chunk itself
-uses non-integral values encoded as strings containing decimal floating point
-numbers.  See the comments in the header file.
-
-Configuration
-
-The main header file function declarations are frequently protected by C
-preprocessing directives of the form:
-
-    #ifdef PNG_feature_SUPPORTED
-    declare-function
-    #endif
-    ...
-    #ifdef PNG_feature_SUPPORTED
-    use-function
-    #endif
-
-The library can be built without support for these APIs, although a
-standard build will have all implemented APIs.  Application programs
-should check the feature macros before using an API for maximum
-portability.  From libpng 1.5.0 the feature macros set during the build
-of libpng are recorded in the header file "pnglibconf.h" and this file
-is always included by png.h.
-
-If you don't need to change the library configuration from the default, skip to
-the next section ("Reading").
-
-Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
-of the build project files in the 'projects' directory simply copy
-scripts/pnglibconf.h.prebuilt to pnglibconf.h.  This means that these build
-systems do not permit easy auto-configuration of the library - they only
-support the default configuration.
-
-The easiest way to make minor changes to the libpng configuration when
-auto-configuration is supported is to add definitions to the command line
-using (typically) CPPFLAGS.  For example:
-
-CPPFLAGS=-DPNG_NO_FLOATING_ARITHMETIC
-
-will change the internal libpng math implementation for gamma correction and
-other arithmetic calculations to fixed point, avoiding the need for fast
-floating point support.  The result can be seen in the generated pnglibconf.h -
-make sure it contains the changed feature macro setting.
-
-If you need to make more extensive configuration changes - more than one or two
-feature macro settings - you can either add -DPNG_USER_CONFIG to the build
-command line and put a list of feature macro settings in pngusr.h or you can set
-DFA_XTRA (a makefile variable) to a file containing the same information in the
-form of 'option' settings.
-
-A. Changing pnglibconf.h
-
-A variety of methods exist to build libpng.  Not all of these support
-reconfiguration of pnglibconf.h.  To reconfigure pnglibconf.h it must either be
-rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
-
-Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to
-pnglibconf.h and changing the lines defining the supported features, paying
-very close attention to the 'option' information in scripts/pnglibconf.dfa
-that describes those features and their requirements.  This is easy to get
-wrong.
-
-B. Configuration using DFA_XTRA
-
-Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
-variant such as 'nawk' or 'gawk', is available.  The configure build will
-automatically find an appropriate awk and build pnglibconf.h.
-The scripts/pnglibconf.mak file contains a set of make rules for doing the
-same thing if configure is not used, and many of the makefiles in the scripts
-directory use this approach.
-
-When rebuilding simply write a new file containing changed options and set
-DFA_XTRA to the name of this file.  This causes the build to append the new file
-to the end of scripts/pnglibconf.dfa.  The pngusr.dfa file should contain lines
-of the following forms:
-
-everything = off
-
-This turns all optional features off.  Include it at the start of pngusr.dfa to
-make it easier to build a minimal configuration.  You will need to turn at least
-some features on afterward to enable either reading or writing code, or both.
-
-option feature on
-option feature off
-
-Enable or disable a single feature.  This will automatically enable other
-features required by a feature that is turned on or disable other features that
-require a feature which is turned off.  Conflicting settings will cause an error
-message to be emitted by awk.
-
-setting feature default value
-
-Changes the default value of setting 'feature' to 'value'.  There are a small
-number of settings listed at the top of pnglibconf.h, they are documented in the
-source code.  Most of these values have performance implications for the library
-but most of them have no visible effect on the API.  Some can also be overridden
-from the API.
-
-This method of building a customized pnglibconf.h is illustrated in
-contrib/pngminim/*.  See the "$(PNGCONF):" target in the makefile and
-pngusr.dfa in these directories.
-
-C. Configuration using PNG_USR_CONFIG
-
-If -DPNG_USR_CONFIG is added to the CFLAGS when pnglibconf.h is built the file
-pngusr.h will automatically be included before the options in
-scripts/pnglibconf.dfa are processed.  Your pngusr.h file should contain only
-macro definitions turning features on or off or setting settings.
-
-Apart from the global setting "everything = off" all the options listed above
-can be set using macros in pngusr.h:
-
-#define PNG_feature_SUPPORTED
-
-is equivalent to:
-
-option feature on
-
-#define PNG_NO_feature
-
-is equivalent to:
-
-option feature off
-
-#define PNG_feature value
-
-is equivalent to:
-
-setting feature default value
-
-Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
-pngusr file you supply override the contents of scripts/pnglibconf.dfa
-
-If confusing or incomprehensible behavior results it is possible to
-examine the intermediate file pnglibconf.dfn to find the full set of
-dependency information for each setting and option.  Simply locate the
-feature in the file and read the C comments that precede it.
-
-This method is also illustrated in the contrib/pngminim/* makefiles and
-pngusr.h.
-
-III. Reading
-
-We'll now walk you through the possible functions to call when reading
-in a PNG file sequentially, briefly explaining the syntax and purpose
-of each one.  See example.c and png.h for more detail.  While
-progressive reading is covered in the next section, you will still
-need some of the functions discussed in this section to read a PNG
-file.
-
-Setup
-
-You will want to do the I/O initialization(*) before you get into libpng,
-so if it doesn't work, you don't have much to undo.  Of course, you
-will also want to insure that you are, in fact, dealing with a PNG
-file.  Libpng provides a simple check to see if a file is a PNG file.
-To use it, pass in the first 1 to 8 bytes of the file to the function
-png_sig_cmp(), and it will return 0 (false) if the bytes match the
-corresponding bytes of the PNG signature, or nonzero (true) otherwise.
-Of course, the more bytes you pass in, the greater the accuracy of the
-prediction.
-
-If you are intending to keep the file pointer open for use in libpng,
-you must ensure you don't read more than 8 bytes from the beginning
-of the file, and you also have to make a call to png_set_sig_bytes_read()
-with the number of bytes you read from the beginning.  Libpng will
-then only check the bytes (if any) that your program didn't read.
-
-(*): If you are not using the standard I/O functions, you will need
-to replace them with custom functions.  See the discussion under
-Customizing libpng.
-
-
-    FILE *fp = fopen(file_name, "rb");
-    if (!fp)
-    {
-       return (ERROR);
-    }
-
-    fread(header, 1, number, fp);
-    is_png = !png_sig_cmp(header, 0, number);
-
-    if (!is_png)
-    {
-       return (NOT_PNG);
-    }
-
-
-Next, png_struct and png_info need to be allocated and initialized.  In
-order to ensure that the size of these structures is correct even with a
-dynamically linked libpng, there are functions to initialize and
-allocate the structures.  We also pass the library version, optional
-pointers to error handling functions, and a pointer to a data struct for
-use by the error functions, if necessary (the pointer and functions can
-be NULL if the default error handlers are to be used).  See the section
-on Changes to Libpng below regarding the old initialization functions.
-The structure allocation functions quietly return NULL if they fail to
-create the structure, so your application should check for that.
-
-    png_structp png_ptr = png_create_read_struct
-        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-        user_error_fn, user_warning_fn);
-
-    if (!png_ptr)
-       return (ERROR);
-
-    png_infop info_ptr = png_create_info_struct(png_ptr);
-
-    if (!info_ptr)
-    {
-       png_destroy_read_struct(&png_ptr,
-           (png_infopp)NULL, (png_infopp)NULL);
-       return (ERROR);
-    }
-
-If you want to use your own memory allocation routines,
-use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
-png_create_read_struct_2() instead of png_create_read_struct():
-
-    png_structp png_ptr = png_create_read_struct_2
-        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-        user_error_fn, user_warning_fn, (png_voidp)
-        user_mem_ptr, user_malloc_fn, user_free_fn);
-
-The error handling routines passed to png_create_read_struct()
-and the memory alloc/free routines passed to png_create_struct_2()
-are only necessary if you are not using the libpng supplied error
-handling and memory alloc/free functions.
-
-When libpng encounters an error, it expects to longjmp back
-to your routine.  Therefore, you will need to call setjmp and pass
-your png_jmpbuf(png_ptr).  If you read the file from different
-routines, you will need to update the longjmp buffer every time you enter
-a new routine that will call a png_*() function.
-
-See your documentation of setjmp/longjmp for your compiler for more
-information on setjmp/longjmp.  See the discussion on libpng error
-handling in the Customizing Libpng section below for more information
-on the libpng error handling.  If an error occurs, and libpng longjmp's
-back to your setjmp, you will want to call png_destroy_read_struct() to
-free any memory.
-
-    if (setjmp(png_jmpbuf(png_ptr)))
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-           &end_info);
-       fclose(fp);
-       return (ERROR);
-    }
-
-Pass (png_infopp)NULL instead of &end_info if you didn't create
-an end_info structure.
-
-If you would rather avoid the complexity of setjmp/longjmp issues,
-you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT() which defaults to abort().
-
-You can #define PNG_ABORT() to a function that does something
-more useful than abort(), as long as your function does not
-return.
-
-Now you need to set up the input code.  The default for libpng is to
-use the C function fread().  If you use this, you will need to pass a
-valid FILE * in the function png_init_io().  Be sure that the file is
-opened in binary mode.  If you wish to handle reading data in another
-way, you need not call the png_init_io() function, but you must then
-implement the libpng I/O methods discussed in the Customizing Libpng
-section below.
-
-    png_init_io(png_ptr, fp);
-
-If you had previously opened the file and read any of the signature from
-the beginning in order to see if this was a PNG file, you need to let
-libpng know that there are some bytes missing from the start of the file.
-
-    png_set_sig_bytes(png_ptr, number);
-
-You can change the zlib compression buffer size to be used while
-reading compressed data with
-
-    png_set_compression_buffer_size(png_ptr, buffer_size);
-
-where the default size is 8192 bytes.  Note that the buffer size
-is changed immediately and the buffer is reallocated immediately,
-instead of setting a flag to be acted upon later.
-
-If you want CRC errors to be handled in a different manner than
-the default, use
-
-    png_set_crc_action(png_ptr, crit_action, ancil_action);
-
-The values for png_set_crc_action() say how libpng is to handle CRC errors in
-ancillary and critical chunks, and whether to use the data contained
-therein.  Note that it is impossible to "discard" data in a critical
-chunk.
-
-Choices for (int) crit_action are
-   PNG_CRC_DEFAULT      0  error/quit
-   PNG_CRC_ERROR_QUIT   1  error/quit
-   PNG_CRC_WARN_USE     3  warn/use data
-   PNG_CRC_QUIET_USE    4  quiet/use data
-   PNG_CRC_NO_CHANGE    5  use the current value
-
-Choices for (int) ancil_action are
-   PNG_CRC_DEFAULT      0  error/quit
-   PNG_CRC_ERROR_QUIT   1  error/quit
-   PNG_CRC_WARN_DISCARD 2  warn/discard data
-   PNG_CRC_WARN_USE     3  warn/use data
-   PNG_CRC_QUIET_USE    4  quiet/use data
-   PNG_CRC_NO_CHANGE    5  use the current value
-
-Setting up callback code
-
-You can set up a callback function to handle any unknown chunks in the
-input stream. You must supply the function
-
-    read_chunk_callback(png_structp png_ptr,
-         png_unknown_chunkp chunk);
-    {
-       /* The unknown chunk structure contains your
-          chunk data, along with similar data for any other
-          unknown chunks: */
-
-           png_byte name[5];
-           png_byte *data;
-           png_size_t size;
-
-       /* Note that libpng has already taken care of
-          the CRC handling */
-
-       /* put your code here.  Search for your chunk in the
-          unknown chunk structure, process it, and return one
-          of the following: */
-
-       return (-n); /* chunk had an error */
-       return (0); /* did not recognize */
-       return (n); /* success */
-    }
-
-(You can give your function another name that you like instead of
-"read_chunk_callback")
-
-To inform libpng about your function, use
-
-    png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
-        read_chunk_callback);
-
-This names not only the callback function, but also a user pointer that
-you can retrieve with
-
-    png_get_user_chunk_ptr(png_ptr);
-
-If you call the png_set_read_user_chunk_fn() function, then all unknown
-chunks will be saved when read, in case your callback function will need
-one or more of them.  This behavior can be changed with the
-png_set_keep_unknown_chunks() function, described below.
-
-At this point, you can set up a callback function that will be
-called after each row has been read, which you can use to control
-a progress meter or the like.  It's demonstrated in pngtest.c.
-You must supply a function
-
-    void read_row_callback(png_structp png_ptr,
-       png_uint_32 row, int pass);
-    {
-      /* put your code here */
-    }
-
-(You can give it another name that you like instead of "read_row_callback")
-
-To inform libpng about your function, use
-
-    png_set_read_status_fn(png_ptr, read_row_callback);
-
-When this function is called the row has already been completely processed and
-the 'row' and 'pass' refer to the next row to be handled.  For the
-non-interlaced case the row that was just handled is simply one less than the
-passed in row number, and pass will always be 0.  For the interlaced case the
-same applies unless the row value is 0, in which case the row just handled was
-the last one from one of the preceding passes.  Because interlacing may skip a
-pass you cannot be sure that the preceding pass is just 'pass-1', if you really
-need to know what the last pass is record (row,pass) from the callback and use
-the last recorded value each time.
-
-As with the user transform you can find the output row using the
-PNG_ROW_FROM_PASS_ROW macro.
-
-Unknown-chunk handling
-
-Now you get to set the way the library processes unknown chunks in the
-input PNG stream. Both known and unknown chunks will be read.  Normal
-behavior is that known chunks will be parsed into information in
-various info_ptr members while unknown chunks will be discarded. This
-behavior can be wasteful if your application will never use some known
-chunk types. To change this, you can call:
-
-    png_set_keep_unknown_chunks(png_ptr, keep,
-        chunk_list, num_chunks);
-    keep       - 0: default unknown chunk handling
-                 1: ignore; do not keep
-                 2: keep only if safe-to-copy
-                 3: keep even if unsafe-to-copy
-
-               You can use these definitions:
-                 PNG_HANDLE_CHUNK_AS_DEFAULT   0
-                 PNG_HANDLE_CHUNK_NEVER        1
-                 PNG_HANDLE_CHUNK_IF_SAFE      2
-                 PNG_HANDLE_CHUNK_ALWAYS       3
-
-    chunk_list - list of chunks affected (a byte string,
-                 five bytes per chunk, NULL or '\0' if
-                 num_chunks is 0)
-
-    num_chunks - number of chunks affected; if 0, all
-                 unknown chunks are affected.  If nonzero,
-                 only the chunks in the list are affected
-
-Unknown chunks declared in this way will be saved as raw data onto a
-list of png_unknown_chunk structures.  If a chunk that is normally
-known to libpng is named in the list, it will be handled as unknown,
-according to the "keep" directive.  If a chunk is named in successive
-instances of png_set_keep_unknown_chunks(), the final instance will
-take precedence.  The IHDR and IEND chunks should not be named in
-chunk_list; if they are, libpng will process them normally anyway.
-If you know that your application will never make use of some particular
-chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below.
-
-Here is an example of the usage of png_set_keep_unknown_chunks(),
-where the private "vpAg" chunk will later be processed by a user chunk
-callback function:
-
-    png_byte vpAg[5]={118, 112,  65, 103, (png_byte) '\0'};
-
-    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-      png_byte unused_chunks[]=
-      {
-        104,  73,  83,  84, (png_byte) '\0',   /* hIST */
-        105,  84,  88, 116, (png_byte) '\0',   /* iTXt */
-        112,  67,  65,  76, (png_byte) '\0',   /* pCAL */
-        115,  67,  65,  76, (png_byte) '\0',   /* sCAL */
-        115,  80,  76,  84, (png_byte) '\0',   /* sPLT */
-        116,  73,  77,  69, (png_byte) '\0',   /* tIME */
-      };
-    #endif
-
-    ...
-
-    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-      /* ignore all unknown chunks: */
-      png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
-
-      /* except for vpAg: */
-      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
-
-      /* also ignore unused known chunks: */
-      png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
-         (int)sizeof(unused_chunks)/5);
-    #endif
-
-User limits
-
-The PNG specification allows the width and height of an image to be as
-large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
-Since very few applications really need to process such large images,
-we have imposed an arbitrary 1-million limit on rows and columns.
-Larger images will be rejected immediately with a png_error() call. If
-you wish to change this limit, you can use
-
-   png_set_user_limits(png_ptr, width_max, height_max);
-
-to set your own limits, or use width_max = height_max = 0x7fffffffL
-to allow all valid dimensions (libpng may reject some very large images
-anyway because of potential buffer overflow conditions).
-
-You should put this statement after you create the PNG structure and
-before calling png_read_info(), png_read_png(), or png_process_data().
-
-When writing a PNG datastream, put this statement before calling
-png_write_info() or png_write_png().
-
-If you need to retrieve the limits that are being applied, use
-
-   width_max = png_get_user_width_max(png_ptr);
-   height_max = png_get_user_height_max(png_ptr);
-
-The PNG specification sets no limit on the number of ancillary chunks
-allowed in a PNG datastream.  You can impose a limit on the total number
-of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with
-
-   png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
-
-where 0x7fffffffL means unlimited.  You can retrieve this limit with
-
-   chunk_cache_max = png_get_chunk_cache_max(png_ptr);
-
-This limit also applies to the number of buffers that can be allocated
-by png_decompress_chunk() while decompressing iTXt, zTXt, and iCCP chunks.
-
-You can also set a limit on the amount of memory that a compressed chunk
-other than IDAT can occupy, with
-
-   png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
-
-and you can retrieve the limit with
-
-   chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
-
-Any chunks that would cause either of these limits to be exceeded will
-be ignored.
-
-Information about your system
-
-If you intend to display the PNG or to incorporate it in other image data you
-need to tell libpng information about your display or drawing surface so that
-libpng can convert the values in the image to match the display.
-
-From libpng-1.5.4 this information can be set before reading the PNG file
-header.  In earlier versions png_set_gamma() existed but behaved incorrectly if
-called before the PNG file header had been read and png_set_alpha_mode() did not
-exist.
-
-If you need to support versions prior to libpng-1.5.4 test the version number
-as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures
-described in the appropriate manual page.
-
-You give libpng the encoding expected by your system expressed as a 'gamma'
-value.  You can also specify a default encoding for the PNG file in
-case the required information is missing from the file.  By default libpng
-assumes that the PNG data matches your system, to keep this default call:
-
-   png_set_gamma(png_ptr, screen_gamma, 1/screen_gamma/*file gamma*/);
-
-or you can use the fixed point equivalent:
-
-   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma, PNG_FP_1/screen_gamma);
-
-If you don't know the gamma for your system it is probably 2.2 - a good
-approximation to the IEC standard for display systems (sRGB).  If images are
-too contrasty or washed out you got the value wrong - check your system
-documentation!
-
-Many systems permit the system gamma to be changed via a lookup table in the
-display driver, a few systems, including older Macs, change the response by
-default.  As of 1.5.4 three special values are available to handle common
-situations:
-
-   PNG_DEFAULT_sRGB: Indicates that the system conforms to the IEC 61966-2-1
-                     standard.  This matches almost all systems.
-   PNG_GAMMA_MAC_18: Indicates that the system is an older (pre Mac OS 10.6)
-                     Apple Macintosh system with the default settings.
-   PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates that the
-                     system expects data with no gamma encoding.
-
-You would use the linear (unencoded) value if you need to process the pixel
-values further because this avoids the need to decode and reencode each
-component value whenever arithmetic is performed.  A lot of graphics software
-uses linear values for this reason, often with higher precision component values
-to preserve overall accuracy.
-
-The second thing you may need to tell libpng about is how your system handles
-alpha channel information.  Some, but not all, PNG files contain an alpha
-channel.  To display these files correctly you need to compose the data onto a
-suitable background, as described in the PNG specification.
-
-Libpng only supports composing onto a single color (using png_set_background;
-see below).  Otherwise you must do the composition yourself and, in this case,
-you may need to call png_set_alpha_mode:
-
-#if PNG_LIBPNG_VER >= 10504
-   png_set_alpha_mode(png_ptr, mode, screen_gamma);
-#else
-   png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma);
-#endif
-
-The screen_gamma value is the same as the argument to png_set_gamma; however,
-how it affects the output depends on the mode.  png_set_alpha_mode() sets the
-file gamma default to 1/screen_gamma, so normally you don't need to call
-png_set_gamma.  If you need different defaults call png_set_gamma() before
-png_set_alpha_mode() - if you call it after it will override the settings made
-by png_set_alpha_mode().
-
-The mode is as follows:
-
-    PNG_ALPHA_PNG: The data is encoded according to the PNG specification.  Red,
-green and blue, or gray, components are gamma encoded color
-values and are not premultiplied by the alpha value.  The
-alpha value is a linear measure of the contribution of the
-pixel to the corresponding final output pixel.
-
-You should normally use this format if you intend to perform
-color correction on the color values; most, maybe all, color
-correction software has no handling for the alpha channel and,
-anyway, the math to handle pre-multiplied component values is
-unnecessarily complex.
-
-Before you do any arithmetic on the component values you need
-to remove the gamma encoding and multiply out the alpha
-channel.  See the PNG specification for more detail.  It is
-important to note that when an image with an alpha channel is
-scaled, linear encoded, pre-multiplied component values must
-be used!
-
-The remaining modes assume you don't need to do any further color correction or
-that if you do, your color correction software knows all about alpha (it
-probably doesn't!)
-
-    PNG_ALPHA_STANDARD:  The data libpng produces
-is encoded in the standard way
-assumed by most correctly written graphics software.
-The gamma encoding will be removed by libpng and the
-linear component values will be pre-multiplied by the
-alpha channel.
-
-With this format the final image must be re-encoded to
-match the display gamma before the image is displayed.
-If your system doesn't do that, yet still seems to
-perform arithmetic on the pixels without decoding them,
-it is broken - check out the modes below.
-
-With PNG_ALPHA_STANDARD libpng always produces linear
-component values, whatever screen_gamma you supply.  The
-screen_gamma value is, however, used as a default for
-the file gamma if the PNG file has no gamma information.
-
-If you call png_set_gamma() after png_set_alpha_mode() you
-will override the linear encoding.  Instead the
-pre-multiplied pixel values will be gamma encoded but
-the alpha channel will still be linear.  This may
-actually match the requirements of some broken software,
-but it is unlikely.
-
-While linear 8-bit data is often used it has
-insufficient precision for any image with a reasonable
-dynamic range.  To avoid problems, and if your software
-supports it, use png_set_expand_16() to force all
-components to 16 bits.
-
-    PNG_ALPHA_OPTIMIZED: This mode is the same
-as PNG_ALPHA_STANDARD except that
-completely opaque pixels are gamma encoded according to
-the screen_gamma value.  Pixels with alpha less than 1.0
-will still have linear components.
-
-Use this format if you have control over your
-compositing software and do don't do other arithmetic
-(such as scaling) on the data you get from libpng.  Your
-compositing software can simply copy opaque pixels to
-the output but still has linear values for the
-non-opaque pixels.
-
-In normal compositing, where the alpha channel encodes
-partial pixel coverage (as opposed to broad area
-translucency), the inaccuracies of the 8-bit
-representation of non-opaque pixels are irrelevant.
-
-You can also try this format if your software is broken;
-it might look better.
-
-    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD;
-however, all component values,
-including the alpha channel are gamma encoded.  This is
-an appropriate format to try if your software, or more
-likely hardware, is totally broken, i.e., if it performs
-linear arithmetic directly on gamma encoded values.
-
-In most cases of broken software or hardware the bug in the final display
-manifests as a subtle halo around composited parts of the image.  You may not
-even perceive this as a halo; the composited part of the image may simply appear
-separate from the background, as though it had been cut out of paper and pasted
-on afterward.
-
-If you don't have to deal with bugs in software or hardware, or if you can fix
-them, there are three recommended ways of using png_set_alpha_mode():
-
-   png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
-       screen_gamma);
-
-You can do color correction on the result (libpng does not currently
-support color correction internally).  When you handle the alpha channel
-you need to undo the gamma encoding and multiply out the alpha.
-
-   png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
-       screen_gamma);
-   png_set_expand_16(png_ptr);
-
-If you are using the high level interface, don't call png_set_expand_16();
-instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
-
-With this mode you can't do color correction, but you can do arithmetic,
-including composition and scaling, on the data without further processing.
-
-   png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
-       screen_gamma);
-
-You can avoid the expansion to 16-bit components with this mode, but you
-lose the ability to scale the image or perform other linear arithmetic.
-All you can do is compose the result onto a matching output.  Since this
-mode is libpng-specific you also need to write your own composition
-software.
-
-If you don't need, or can't handle, the alpha channel you can call
-png_set_background() to remove it by compositing against a fixed color.  Don't
-call png_set_strip_alpha() to do this - it will leave spurious pixel values in
-transparent parts of this image.
-
-   png_set_background(png_ptr, &background_color,
-       PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
-
-The background_color is an RGB or grayscale value according to the data format
-libpng will produce for you.  Because you don't yet know the format of the PNG
-file, if you call png_set_background at this point you must arrange for the
-format produced by libpng to always have 8-bit or 16-bit components and then
-store the color as an 8-bit or 16-bit color as appropriate.  The color contains
-separate gray and RGB component values, so you can let libpng produce gray or
-RGB output according to the input format, but low bit depth grayscale images
-must always be converted to at least 8-bit format.  (Even though low bit depth
-grayscale images can't have an alpha channel they can have a transparent
-color!)
-
-You set the transforms you need later, either as flags to the high level
-interface or libpng API calls for the low level interface.  For reference the
-settings and API calls required are:
-
-8-bit values:
-   PNG_TRANSFORM_SCALE_16 | PNG_EXPAND
-   png_set_expand(png_ptr); png_set_scale_16(png_ptr);
-
-   If you must get exactly the same inaccurate results
-   produced by default in versions prior to libpng-1.5.4,
-   use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr)
-   instead.
-
-16-bit values:
-   PNG_TRANSFORM_EXPAND_16
-   png_set_expand_16(png_ptr);
-
-In either case palette image data will be expanded to RGB.  If you just want
-color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
-to the list.
-
-Calling png_set_background before the PNG file header is read will not work
-prior to libpng-1.5.4.  Because the failure may result in unexpected warnings or
-errors it is therefore much safer to call png_set_background after the head has
-been read.  Unfortunately this means that prior to libpng-1.5.4 it cannot be
-used with the high level interface.
-
-The high-level read interface
-
-At this point there are two ways to proceed; through the high-level
-read interface, or through a sequence of low-level read operations.
-You can use the high-level interface if (a) you are willing to read
-the entire image into memory, and (b) the input transformations
-you want to do are limited to the following set:
-
-    PNG_TRANSFORM_IDENTITY      No transformation
-    PNG_TRANSFORM_SCALE_16      Strip 16-bit samples to
-                                8-bit accurately
-    PNG_TRANSFORM_STRIP_16      Chop 16-bit samples to
-                                8-bit less accurately
-    PNG_TRANSFORM_STRIP_ALPHA   Discard the alpha channel
-    PNG_TRANSFORM_PACKING       Expand 1, 2 and 4-bit
-                                samples to bytes
-    PNG_TRANSFORM_PACKSWAP      Change order of packed
-                                pixels to LSB first
-    PNG_TRANSFORM_EXPAND        Perform set_expand()
-    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
-    PNG_TRANSFORM_SHIFT         Normalize pixels to the
-                                sBIT depth
-    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
-                                to BGRA
-    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
-                                to AG
-    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
-                                to transparency
-    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
-    PNG_TRANSFORM_GRAY_TO_RGB   Expand grayscale samples
-                                to RGB (or GA to RGBA)
-    PNG_TRANSFORM_EXPAND_16     Expand samples to 16 bits
-
-(This excludes setting a background color, doing gamma transformation,
-quantizing, and setting filler.)  If this is the case, simply do this:
-
-    png_read_png(png_ptr, info_ptr, png_transforms, NULL)
-
-where png_transforms is an integer containing the bitwise OR of some
-set of transformation flags.  This call is equivalent to png_read_info(),
-followed the set of transformations indicated by the transform mask,
-then png_read_image(), and finally png_read_end().
-
-(The final parameter of this call is not yet used.  Someday it might point
-to transformation parameters required by some future input transform.)
-
-You must use png_transforms and not call any png_set_transform() functions
-when you use png_read_png().
-
-After you have called png_read_png(), you can retrieve the image data
-with
-
-   row_pointers = png_get_rows(png_ptr, info_ptr);
-
-where row_pointers is an array of pointers to the pixel data for each row:
-
-   png_bytep row_pointers[height];
-
-If you know your image size and pixel size ahead of time, you can allocate
-row_pointers prior to calling png_read_png() with
-
-   if (height > PNG_UINT_32_MAX/png_sizeof(png_byte))
-      png_error (png_ptr,
-          "Image is too tall to process in memory");
-
-   if (width > PNG_UINT_32_MAX/pixel_size)
-      png_error (png_ptr,
-          "Image is too wide to process in memory");
-
-   row_pointers = png_malloc(png_ptr,
-       height*png_sizeof(png_bytep));
-
-   for (int i=0; i<height, i++)
-      row_pointers[i]=NULL;  /* security precaution */
-
-   for (int i=0; i<height, i++)
-      row_pointers[i]=png_malloc(png_ptr,
-          width*pixel_size);
-
-   png_set_rows(png_ptr, info_ptr, &row_pointers);
-
-Alternatively you could allocate your image in one big block and define
-row_pointers[i] to point into the proper places in your block.
-
-If you use png_set_rows(), the application is responsible for freeing
-row_pointers (and row_pointers[i], if they were separately allocated).
-
-If you don't allocate row_pointers ahead of time, png_read_png() will
-do it, and it'll be free'ed by libpng when you call png_destroy_*().
-
-The low-level read interface
-
-If you are going the low-level route, you are now ready to read all
-the file information up to the actual image data.  You do this with a
-call to png_read_info().
-
-    png_read_info(png_ptr, info_ptr);
-
-This will process all chunks up to but not including the image data.
-
-This also copies some of the data from the PNG file into the decode structure
-for use in later transformations.  Important information copied in is:
-
-1) The PNG file gamma from the gAMA chunk.  This overwrites the default value
-provided by an earlier call to png_set_gamma or png_set_alpha_mode.
-
-2) Prior to libpng-1.5.4 the background color from a bKGd chunk.  This
-damages the information provided by an earlier call to png_set_background
-resulting in unexpected behavior.  Libpng-1.5.4 no longer does this.
-
-3) The number of significant bits in each component value.  Libpng uses this to
-optimize gamma handling by reducing the internal lookup table sizes.
-
-4) The transparent color information from a tRNS chunk.  This can be modified by
-a later call to png_set_tRNS.
-
-Querying the info structure
-
-Functions are used to get the information from the info_ptr once it
-has been read.  Note that these fields may not be completely filled
-in until png_read_end() has read the chunk data following the image.
-
-    png_get_IHDR(png_ptr, info_ptr, &width, &height,
-       &bit_depth, &color_type, &interlace_type,
-       &compression_type, &filter_method);
-
-    width          - holds the width of the image
-                     in pixels (up to 2^31).
-
-    height         - holds the height of the image
-                     in pixels (up to 2^31).
-
-    bit_depth      - holds the bit depth of one of the
-                     image channels.  (valid values are
-                     1, 2, 4, 8, 16 and depend also on
-                     the color_type.  See also
-                     significant bits (sBIT) below).
-
-    color_type     - describes which color/alpha channels
-                         are present.
-                     PNG_COLOR_TYPE_GRAY
-                        (bit depths 1, 2, 4, 8, 16)
-                     PNG_COLOR_TYPE_GRAY_ALPHA
-                        (bit depths 8, 16)
-                     PNG_COLOR_TYPE_PALETTE
-                        (bit depths 1, 2, 4, 8)
-                     PNG_COLOR_TYPE_RGB
-                        (bit_depths 8, 16)
-                     PNG_COLOR_TYPE_RGB_ALPHA
-                        (bit_depths 8, 16)
-
-                     PNG_COLOR_MASK_PALETTE
-                     PNG_COLOR_MASK_COLOR
-                     PNG_COLOR_MASK_ALPHA
-
-    interlace_type - (PNG_INTERLACE_NONE or
-                     PNG_INTERLACE_ADAM7)
-
-    compression_type - (must be PNG_COMPRESSION_TYPE_BASE
-                     for PNG 1.0)
-
-    filter_method  - (must be PNG_FILTER_TYPE_BASE
-                     for PNG 1.0, and can also be
-                     PNG_INTRAPIXEL_DIFFERENCING if
-                     the PNG datastream is embedded in
-                     a MNG-1.0 datastream)
-
-    Any or all of interlace_type, compression_type, or
-    filter_method can be NULL if you are
-    not interested in their values.
-
-    Note that png_get_IHDR() returns 32-bit data into
-    the application's width and height variables.
-    This is an unsafe situation if these are 16-bit
-    variables.  In such situations, the
-    png_get_image_width() and png_get_image_height()
-    functions described below are safer.
-
-    width            = png_get_image_width(png_ptr,
-                         info_ptr);
-
-    height           = png_get_image_height(png_ptr,
-                         info_ptr);
-
-    bit_depth        = png_get_bit_depth(png_ptr,
-                         info_ptr);
-
-    color_type       = png_get_color_type(png_ptr,
-                         info_ptr);
-
-    interlace_type   = png_get_interlace_type(png_ptr,
-                         info_ptr);
-
-    compression_type = png_get_compression_type(png_ptr,
-                         info_ptr);
-
-    filter_method    = png_get_filter_type(png_ptr,
-                         info_ptr);
-
-    channels = png_get_channels(png_ptr, info_ptr);
-
-    channels       - number of channels of info for the
-                     color type (valid values are 1 (GRAY,
-                     PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
-                     4 (RGB_ALPHA or RGB + filler byte))
-
-    rowbytes = png_get_rowbytes(png_ptr, info_ptr);
-
-    rowbytes       - number of bytes needed to hold a row
-
-    signature = png_get_signature(png_ptr, info_ptr);
-
-    signature      - holds the signature read from the
-                     file (if any).  The data is kept in
-                     the same offset it would be if the
-                     whole signature were read (i.e. if an
-                     application had already read in 4
-                     bytes of signature before starting
-                     libpng, the remaining 4 bytes would
-                     be in signature[4] through signature[7]
-                     (see png_set_sig_bytes())).
-
-These are also important, but their validity depends on whether the chunk
-has been read.  The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
-png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
-data has been read, or zero if it is missing.  The parameters to the
-png_get_<chunk> are set directly if they are simple data types, or a
-pointer into the info_ptr is returned for any complex types.
-
-    png_get_PLTE(png_ptr, info_ptr, &palette,
-                     &num_palette);
-
-    palette        - the palette for the file
-                     (array of png_color)
-
-    num_palette    - number of entries in the palette
-
-    png_get_gAMA(png_ptr, info_ptr, &file_gamma);
-    png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
-
-    file_gamma     - the gamma at which the file is
-                     written (PNG_INFO_gAMA)
-
-    int_file_gamma - 100,000 times the gamma at which the
-                     file is written
-
-    png_get_cHRM(png_ptr, info_ptr,  &white_x, &white_y, &red_x, &red_y,
-                     &green_x, &green_y, &blue_x, &blue_y)
-    png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z, &green_X,
-                     &green_Y, &green_Z, &blue_X, &blue_Y, &blue_Z)
-    png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x, &int_white_y,
-                     &int_red_x, &int_red_y, &int_green_x, &int_green_y,
-                     &int_blue_x, &int_blue_y)
-    png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y,
-                     &int_red_Z, &int_green_X, &int_green_Y, &int_green_Z,
-                     &int_blue_X, &int_blue_Y, &int_blue_Z)
-
-    {white,red,green,blue}_{x,y}
-                     A color space encoding specified using the chromaticities
-                     of the end points and the white point. (PNG_INFO_cHRM)
-
-    {red,green,blue}_{X,Y,Z}
-                     A color space encoding specified using the encoding end
-                     points - the CIE tristimulus specification of the intended
-                     color of the red, green and blue channels in the PNG RGB
-                     data.  The white point is simply the sum of the three end
-                     points. (PNG_INFO_cHRM)
-
-    png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
-
-    file_srgb_intent - the rendering intent (PNG_INFO_sRGB)
-                     The presence of the sRGB chunk
-                     means that the pixel data is in the
-                     sRGB color space.  This chunk also
-                     implies specific values of gAMA and
-                     cHRM.
-
-    png_get_iCCP(png_ptr, info_ptr, &name,
-       &compression_type, &profile, &proflen);
-
-    name             - The profile name.
-
-    compression_type - The compression type; always
-                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
-                       You may give NULL to this argument to
-                       ignore it.
-
-    profile          - International Color Consortium color
-                       profile data. May contain NULs.
-
-    proflen          - length of profile data in bytes.
-
-    png_get_sBIT(png_ptr, info_ptr, &sig_bit);
-
-    sig_bit        - the number of significant bits for
-                     (PNG_INFO_sBIT) each of the gray,
-                     red, green, and blue channels,
-                     whichever are appropriate for the
-                     given color type (png_color_16)
-
-    png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
-                     &num_trans, &trans_color);
-
-    trans_alpha    - array of alpha (transparency)
-                     entries for palette (PNG_INFO_tRNS)
-
-    num_trans      - number of transparent entries
-                     (PNG_INFO_tRNS)
-
-    trans_color    - graylevel or color sample values of
-                     the single transparent color for
-                     non-paletted images (PNG_INFO_tRNS)
-
-    png_get_hIST(png_ptr, info_ptr, &hist);
-                     (PNG_INFO_hIST)
-
-    hist           - histogram of palette (array of
-                     png_uint_16)
-
-    png_get_tIME(png_ptr, info_ptr, &mod_time);
-
-    mod_time       - time image was last modified
-                    (PNG_VALID_tIME)
-
-    png_get_bKGD(png_ptr, info_ptr, &background);
-
-    background     - background color (of type
-                     png_color_16p) (PNG_VALID_bKGD)
-                     valid 16-bit red, green and blue
-                     values, regardless of color_type
-
-    num_comments   = png_get_text(png_ptr, info_ptr,
-                     &text_ptr, &num_text);
-
-    num_comments   - number of comments
-
-    text_ptr       - array of png_text holding image
-                     comments
-
-    text_ptr[i].compression - type of compression used
-                 on "text" PNG_TEXT_COMPRESSION_NONE
-                           PNG_TEXT_COMPRESSION_zTXt
-                           PNG_ITXT_COMPRESSION_NONE
-                           PNG_ITXT_COMPRESSION_zTXt
-
-    text_ptr[i].key   - keyword for comment.  Must contain
-                         1-79 characters.
-
-    text_ptr[i].text  - text comments for current
-                         keyword.  Can be empty.
-
-    text_ptr[i].text_length - length of text string,
-                 after decompression, 0 for iTXt
-
-    text_ptr[i].itxt_length - length of itxt string,
-                 after decompression, 0 for tEXt/zTXt
-
-    text_ptr[i].lang  - language of comment (empty
-                         string for unknown).
-
-    text_ptr[i].lang_key  - keyword in UTF-8
-                         (empty string for unknown).
-
-    Note that the itxt_length, lang, and lang_key
-    members of the text_ptr structure only exist when the
-    library is built with iTXt chunk support.  Prior to
-    libpng-1.4.0 the library was built by default without
-    iTXt support. Also note that when iTXt is supported,
-    they contain NULL pointers when the "compression"
-    field contains PNG_TEXT_COMPRESSION_NONE or
-    PNG_TEXT_COMPRESSION_zTXt.
-
-    num_text       - number of comments (same as
-                     num_comments; you can put NULL here
-                     to avoid the duplication)
-
-    Note while png_set_text() will accept text, language,
-    and translated keywords that can be NULL pointers, the
-    structure returned by png_get_text will always contain
-    regular zero-terminated C strings.  They might be
-    empty strings but they will never be NULL pointers.
-
-    num_spalettes = png_get_sPLT(png_ptr, info_ptr,
-       &palette_ptr);
-
-    num_spalettes  - number of sPLT chunks read.
-
-    palette_ptr    - array of palette structures holding
-                     contents of one or more sPLT chunks
-                     read.
-
-    png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
-       &unit_type);
-
-    offset_x       - positive offset from the left edge
-                     of the screen (can be negative)
-
-    offset_y       - positive offset from the top edge
-                     of the screen (can be negative)
-
-    unit_type      - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
-
-    png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
-       &unit_type);
-
-    res_x          - pixels/unit physical resolution in
-                     x direction
-
-    res_y          - pixels/unit physical resolution in
-                     x direction
-
-    unit_type      - PNG_RESOLUTION_UNKNOWN,
-                     PNG_RESOLUTION_METER
-
-    png_get_sCAL(png_ptr, info_ptr, &unit, &width,
-       &height)
-
-    unit        - physical scale units (an integer)
-
-    width       - width of a pixel in physical scale units
-
-    height      - height of a pixel in physical scale units
-                 (width and height are doubles)
-
-    png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
-       &height)
-
-    unit        - physical scale units (an integer)
-
-    width       - width of a pixel in physical scale units
-                  (expressed as a string)
-
-    height      - height of a pixel in physical scale units
-                 (width and height are strings like "2.54")
-
-    num_unknown_chunks = png_get_unknown_chunks(png_ptr,
-       info_ptr, &unknowns)
-
-    unknowns          - array of png_unknown_chunk
-                        structures holding unknown chunks
-
-    unknowns[i].name  - name of unknown chunk
-
-    unknowns[i].data  - data of unknown chunk
-
-    unknowns[i].size  - size of unknown chunk's data
-
-    unknowns[i].location - position of chunk in file
-
-    The value of "i" corresponds to the order in which the
-    chunks were read from the PNG file or inserted with the
-    png_set_unknown_chunks() function.
-
-    The value of "location" is a bitwise "or" of
-
-         PNG_HAVE_IHDR  (0x01)
-         PNG_HAVE_PLTE  (0x02)
-         PNG_AFTER_IDAT (0x08)
-
-The data from the pHYs chunk can be retrieved in several convenient
-forms:
-
-    res_x = png_get_x_pixels_per_meter(png_ptr,
-       info_ptr)
-
-    res_y = png_get_y_pixels_per_meter(png_ptr,
-       info_ptr)
-
-    res_x_and_y = png_get_pixels_per_meter(png_ptr,
-       info_ptr)
-
-    res_x = png_get_x_pixels_per_inch(png_ptr,
-       info_ptr)
-
-    res_y = png_get_y_pixels_per_inch(png_ptr,
-       info_ptr)
-
-    res_x_and_y = png_get_pixels_per_inch(png_ptr,
-       info_ptr)
-
-    aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
-       info_ptr)
-
-    Each of these returns 0 [signifying "unknown"] if
-       the data is not present or if res_x is 0;
-       res_x_and_y is 0 if res_x != res_y
-
-    Note that because of the way the resolutions are
-       stored internally, the inch conversions won't
-       come out to exactly even number.  For example,
-       72 dpi is stored as 0.28346 pixels/meter, and
-       when this is retrieved it is 71.9988 dpi, so
-       be sure to round the returned value appropriately
-       if you want to display a reasonable-looking result.
-
-The data from the oFFs chunk can be retrieved in several convenient
-forms:
-
-    x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
-
-    y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
-
-    x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
-
-    y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
-
-    Each of these returns 0 [signifying "unknown" if both
-       x and y are 0] if the data is not present or if the
-       chunk is present but the unit is the pixel.  The
-       remark about inexact inch conversions applies here
-       as well, because a value in inches can't always be
-       converted to microns and back without some loss
-       of precision.
-
-For more information, see the
-PNG specification for chunk contents.  Be careful with trusting
-rowbytes, as some of the transformations could increase the space
-needed to hold a row (expand, filler, gray_to_rgb, etc.).
-See png_read_update_info(), below.
-
-A quick word about text_ptr and num_text.  PNG stores comments in
-keyword/text pairs, one pair per chunk, with no limit on the number
-of text chunks, and a 2^31 byte limit on their size.  While there are
-suggested keywords, there is no requirement to restrict the use to these
-strings.  It is strongly suggested that keywords and text be sensible
-to humans (that's the point), so don't use abbreviations.  Non-printing
-symbols are not allowed.  See the PNG specification for more details.
-There is also no requirement to have text after the keyword.
-
-Keywords should be limited to 79 Latin-1 characters without leading or
-trailing spaces, but non-consecutive spaces are allowed within the
-keyword.  It is possible to have the same keyword any number of times.
-The text_ptr is an array of png_text structures, each holding a
-pointer to a language string, a pointer to a keyword and a pointer to
-a text string.  The text string, language code, and translated
-keyword may be empty or NULL pointers.  The keyword/text
-pairs are put into the array in the order that they are received.
-However, some or all of the text chunks may be after the image, so, to
-make sure you have read all the text chunks, don't mess with these
-until after you read the stuff after the image.  This will be
-mentioned again below in the discussion that goes with png_read_end().
-
-Input transformations
-
-After you've read the header information, you can set up the library
-to handle any special transformations of the image data.  The various
-ways to transform the data will be described in the order that they
-should occur.  This is important, as some of these change the color
-type and/or bit depth of the data, and some others only work on
-certain color types and bit depths.
-
-Transformations you request are ignored if they don't have any meaning for a
-particular input data format.  However some transformations can have an effect
-as a result of a previous transformation.  If you specify a contradictory set of
-transformations, for example both adding and removing the alpha channel, you
-cannot predict the final result.
-
-The color used for the transparency values should be supplied in the same
-format/depth as the current image data.  It is stored in the same format/depth
-as the image data in a tRNS chunk, so this is what libpng expects for this data.
-
-The color used for the background value depends on the need_expand argument as
-described below.
-
-Data will be decoded into the supplied row buffers packed into bytes
-unless the library has been told to transform it into another format.
-For example, 4 bit/pixel paletted or grayscale data will be returned
-2 pixels/byte with the leftmost pixel in the high-order bits of the
-byte, unless png_set_packing() is called.  8-bit RGB data will be stored
-in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
-is called to insert filler bytes, either before or after each RGB triplet.
-16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
-byte of the color value first, unless png_set_scale_16() is called to
-transform it to regular RGB RGB triplets, or png_set_filler() or
-png_set_add alpha() is called to insert filler bytes, either before or
-after each RRGGBB triplet.  Similarly, 8-bit or 16-bit grayscale data can
-be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(),
-or png_set_scale_16().
-
-The following code transforms grayscale images of less than 8 to 8 bits,
-changes paletted images to RGB, and adds a full alpha channel if there is
-transparency information in a tRNS chunk.  This is most useful on
-grayscale images with bit depths of 2 or 4 or if there is a multiple-image
-viewing application that wishes to treat all images in the same way.
-
-    if (color_type == PNG_COLOR_TYPE_PALETTE)
-        png_set_palette_to_rgb(png_ptr);
-
-    if (png_get_valid(png_ptr, info_ptr,
-        PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
-
-    if (color_type == PNG_COLOR_TYPE_GRAY &&
-        bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
-
-The first two functions are actually aliases for png_set_expand(), added
-in libpng version 1.0.4, with the function names expanded to improve code
-readability.  In some future version they may actually do different
-things.
-
-As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
-added.  It expands the sample depth without changing tRNS to alpha.
-
-As of libpng version 1.5.2, png_set_expand_16() was added.  It behaves as
-png_set_expand(); however, the resultant channels have 16 bits rather than 8.
-Use this when the output color or gray channels are made linear to avoid fairly
-severe accuracy loss.
-
-   if (bit_depth < 16)
-      png_set_expand_16(png_ptr);
-
-PNG can have files with 16 bits per channel.  If you only can handle
-8 bits per channel, this will strip the pixels down to 8-bit.
-
-    if (bit_depth == 16)
-#if PNG_LIBPNG_VER >= 10504
-       png_set_scale_16(png_ptr);
-#else
-       png_set_strip_16(png_ptr);
-#endif
-
-(The more accurate "png_set_scale_16()" API became available in libpng version
-1.5.4).
-
-If you need to process the alpha channel on the image separately from the image
-data (for example if you convert it to a bitmap mask) it is possible to have
-libpng strip the channel leaving just RGB or gray data:
-
-    if (color_type & PNG_COLOR_MASK_ALPHA)
-       png_set_strip_alpha(png_ptr);
-
-If you strip the alpha channel you need to find some other way of dealing with
-the information.  If, instead, you want to convert the image to an opaque
-version with no alpha channel use png_set_background; see below.
-
-As of libpng version 1.5.2, almost all useful expansions are supported, the
-major ommissions are conversion of grayscale to indexed images (which can be
-done trivially in the application) and conversion of indexed to grayscale (which
-can be done by a trivial manipulation of the palette.)
-
-In the following table, the 01 means grayscale with depth<8, 31 means
-indexed with depth<8, other numerals represent the color type, "T" means
-the tRNS chunk is present, A means an alpha channel is present, and O
-means tRNS or alpha is present but all pixels in the image are opaque.
-
-  FROM  01  31   0  0T  0O   2  2T  2O   3  3T  3O  4A  4O  6A  6O
-   TO
-   01    -  [G]  -   -   -   -   -   -   -   -   -   -   -   -   -
-   31   [Q]  Q  [Q] [Q] [Q]  Q   Q   Q   Q   Q   Q  [Q] [Q]  Q   Q
-    0    1   G   +   .   .   G   G   G   G   G   G   B   B  GB  GB
-   0T    lt  Gt  t   +   .   Gt  G   G   Gt  G   G   Bt  Bt GBt GBt
-   0O    lt  Gt  t   .   +   Gt  Gt  G   Gt  Gt  G   Bt  Bt GBt GBt
-    2    C   P   C   C   C   +   .   .   C   -   -  CB  CB   B   B
-   2T    Ct  -   Ct  C   C   t   +   t   -   -   -  CBt CBt  Bt  Bt
-   2O    Ct  -   Ct  C   C   t   t   +   -   -   -  CBt CBt  Bt  Bt
-    3   [Q]  p  [Q] [Q] [Q]  Q   Q   Q   +   .   .  [Q] [Q]  Q   Q
-   3T   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   +   t  [Qt][Qt] Qt  Qt
-   3O   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   t   +  [Qt][Qt] Qt  Qt
-   4A    lA  G   A   T   T   GA  GT  GT  GA  GT  GT  +   BA  G  GBA
-   4O    lA GBA  A   T   T   GA  GT  GT  GA  GT  GT  BA  +  GBA  G
-   6A    CA  PA  CA  C   C   A   T  tT   PA  P   P   C  CBA  +   BA
-   6O    CA PBA  CA  C   C   A  tT   T   PA  P   P  CBA  C   BA  +
-
-Within the matrix,
-     "+" identifies entries where 'from' and 'to' are the same.
-     "-" means the transformation is not supported.
-     "." means nothing is necessary (a tRNS chunk can just be ignored).
-     "t" means the transformation is obtained by png_set_tRNS.
-     "A" means the transformation is obtained by png_set_add_alpha().
-     "X" means the transformation is obtained by png_set_expand().
-     "1" means the transformation is obtained by
-         png_set_expand_gray_1_2_4_to_8() (and by png_set_expand() if there
-         is no transparency in the original or the final format).
-     "C" means the transformation is obtained by png_set_gray_to_rgb().
-     "G" means the transformation is obtained by png_set_rgb_to_gray().
-     "P" means the transformation is obtained by
-         png_set_expand_palette_to_rgb().
-     "p" means the transformation is obtained by png_set_packing().
-     "Q" means the transformation is obtained by png_set_quantize().
-     "T" means the transformation is obtained by png_set_tRNS_to_alpha().
-     "B" means the transformation is obtained by png_set_background(), or
-         png_strip_alpha().
-
-When an entry has multiple transforms listed all are required to cause the
-right overall transformation.  When two transforms are separated by a comma
-either will do the job.  When transforms are enclosed in [] the transform should
-do the job but this is currently unimplemented - a different format will result
-if the suggested transformations are used.
-
-In PNG files, the alpha channel in an image
-is the level of opacity.  If you need the alpha channel in an image to
-be the level of transparency instead of opacity, you can invert the
-alpha channel (or the tRNS chunk data) after it's read, so that 0 is
-fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
-images) is fully transparent, with
-
-    png_set_invert_alpha(png_ptr);
-
-PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
-they can, resulting in, for example, 8 pixels per byte for 1 bit
-files.  This code expands to 1 pixel per byte without changing the
-values of the pixels:
-
-    if (bit_depth < 8)
-       png_set_packing(png_ptr);
-
-PNG files have possible bit depths of 1, 2, 4, 8, and 16.  All pixels
-stored in a PNG image have been "scaled" or "shifted" up to the next
-higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
-to 8 bits/sample in the range [0, 255]).  However, it is also possible
-to convert the PNG pixel data back to the original bit depth of the
-image.  This call reduces the pixels back down to the original bit depth:
-
-    png_color_8p sig_bit;
-
-    if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
-       png_set_shift(png_ptr, sig_bit);
-
-PNG files store 3-color pixels in red, green, blue order.  This code
-changes the storage of the pixels to blue, green, red:
-
-    if (color_type == PNG_COLOR_TYPE_RGB ||
-        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-       png_set_bgr(png_ptr);
-
-PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
-into 4 or 8 bytes for windowing systems that need them in this format:
-
-    if (color_type == PNG_COLOR_TYPE_RGB)
-       png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
-
-where "filler" is the 8 or 16-bit number to fill with, and the location is
-either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
-you want the filler before the RGB or after.  This transformation
-does not affect images that already have full alpha channels.  To add an
-opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which
-will generate RGBA pixels.
-
-Note that png_set_filler() does not change the color type.  If you want
-to do that, you can add a true alpha channel with
-
-    if (color_type == PNG_COLOR_TYPE_RGB ||
-       color_type == PNG_COLOR_TYPE_GRAY)
-       png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
-
-where "filler" contains the alpha value to assign to each pixel.
-This function was added in libpng-1.2.7.
-
-If you are reading an image with an alpha channel, and you need the
-data as ARGB instead of the normal PNG format RGBA:
-
-    if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-       png_set_swap_alpha(png_ptr);
-
-For some uses, you may want a grayscale image to be represented as
-RGB.  This code will do that conversion:
-
-    if (color_type == PNG_COLOR_TYPE_GRAY ||
-        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-       png_set_gray_to_rgb(png_ptr);
-
-Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
-with alpha.
-
-    if (color_type == PNG_COLOR_TYPE_RGB ||
-        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-       png_set_rgb_to_gray(png_ptr, error_action, double red_weight,
-          double green_weight);
-
-    error_action = 1: silently do the conversion
-
-    error_action = 2: issue a warning if the original
-                      image has any pixel where
-                      red != green or red != blue
-
-    error_action = 3: issue an error and abort the
-                      conversion if the original
-                      image has any pixel where
-                      red != green or red != blue
-
-    red_weight:       weight of red component
-
-    green_weight:     weight of green component
-                      If either weight is negative, default
-                      weights are used.
-
-In the corresponding fixed point API the red_weight and green_weight values are
-simply scaled by 100,000:
-
-    png_set_rgb_to_gray(png_ptr, error_action, png_fixed_point red_weight,
-       png_fixed_point green_weight);
-
-If you have set error_action = 1 or 2, you can
-later check whether the image really was gray, after processing
-the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
-It will return a png_byte that is zero if the image was gray or
-1 if there were any non-gray pixels.  Background and sBIT data
-will be silently converted to grayscale, using the green channel
-data for sBIT, regardless of the error_action setting.
-
-The default values come from the PNG file cHRM chunk if present; otherwise, the
-defaults correspond to the ITU-R recommendation 709, and also the sRGB color
-space, as recommended in the Charles Poynton's Colour FAQ,
-<http://www.poynton.com/>, in section 9:
-
-   <http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
-
-    Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
-
-Previous versions of this document, 1998 through 2002, recommended a slightly
-different formula:
-
-    Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
-
-Libpng uses an integer approximation:
-
-    Y = (6968 * R + 23434 * G + 2366 * B)/32768
-
-The calculation is done in a linear colorspace, if the image gamma
-can be determined.
-
-The png_set_background() function has been described already; it tells libpng to
-composite images with alpha or simple transparency against the supplied
-background color.  For compatibility with versions of libpng earlier than
-libpng-1.5.4 it is recommended that you call the function after reading the file
-header, even if you don't want to use the color in a bKGD chunk, if one exists.
-
-If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
-you may use this color, or supply another color more suitable for
-the current display (e.g., the background color from a web page).  You
-need to tell libpng how the color is represented, both the format of the
-component values in the color (the number of bits) and the gamma encoding of the
-color.  The function takes two arguments, background_gamma_mode and need_expand
-to convey this information, however only two combinations are likely to be
-useful:
-
-    png_color_16 my_background;
-    png_color_16p image_background;
-
-    if (png_get_bKGD(png_ptr, info_ptr, &image_background))
-       png_set_background(png_ptr, image_background,
-           PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
-    else
-       png_set_background(png_ptr, &my_background,
-           PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
-
-The second call was described above - my_background is in the format of the
-final, display, output produced by libpng.  Because you now know the format of
-the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
-output and to retain palette images (the palette colors will be modified
-appropriately and the tRNS chunk removed.)  However, if you are doing this,
-take great care not to ask for transformations without checking first that
-they apply!
-
-In the first call the background color has the original bit depth and color type
-of the PNG file.  So, for palette images the color is supplied as a palette
-index and for low bit greyscale images the color is a reduced bit value in
-image_background->gray.
-
-If you didn't call png_set_gamma() before reading the file header, for example
-if you need your code to remain compatible with older versions of libpng prior
-to libpng-1.5.4, this is the place to call it.
-
-Do not call it if you called png_set_alpha_mode(); doing so will damage the
-settings put in place by png_set_alpha_mode().  (If png_set_alpha_mode() is
-supported then you can certainly do png_set_gamma() before reading the PNG
-header.)
-
-This API unconditionally sets the screen and file gamma values, so it will
-override the value in the PNG file unless it is called before the PNG file
-reading starts.  For this reason you must always call it with the PNG file
-value when you call it in this position:
-
-   if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
-      png_set_gamma(png_ptr, screen_gamma, file_gamma);
-
-   else
-      png_set_gamma(png_ptr, screen_gamma, 0.45455);
-
-If you need to reduce an RGB file to a paletted file, or if a paletted
-file has more entries then will fit on your screen, png_set_quantize()
-will do that.  Note that this is a simple match quantization that merely
-finds the closest color available.  This should work fairly well with
-optimized palettes, but fairly badly with linear color cubes.  If you
-pass a palette that is larger than maximum_colors, the file will
-reduce the number of colors in the palette so it will fit into
-maximum_colors.  If there is a histogram, libpng will use it to make
-more intelligent choices when reducing the palette.  If there is no
-histogram, it may not do as good a job.
-
-   if (color_type & PNG_COLOR_MASK_COLOR)
-   {
-      if (png_get_valid(png_ptr, info_ptr,
-          PNG_INFO_PLTE))
-      {
-         png_uint_16p histogram = NULL;
-
-         png_get_hIST(png_ptr, info_ptr,
-             &histogram);
-         png_set_quantize(png_ptr, palette, num_palette,
-            max_screen_colors, histogram, 1);
-      }
-
-      else
-      {
-         png_color std_color_cube[MAX_SCREEN_COLORS] =
-            { ... colors ... };
-
-         png_set_quantize(png_ptr, std_color_cube,
-            MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
-            NULL,0);
-      }
-   }
-
-PNG files describe monochrome as black being zero and white being one.
-The following code will reverse this (make black be one and white be
-zero):
-
-   if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
-      png_set_invert_mono(png_ptr);
-
-This function can also be used to invert grayscale and gray-alpha images:
-
-   if (color_type == PNG_COLOR_TYPE_GRAY ||
-       color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      png_set_invert_mono(png_ptr);
-
-PNG files store 16-bit pixels in network byte order (big-endian,
-ie. most significant bits first).  This code changes the storage to the
-other way (little-endian, i.e. least significant bits first, the
-way PCs store them):
-
-    if (bit_depth == 16)
-       png_set_swap(png_ptr);
-
-If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
-need to change the order the pixels are packed into bytes, you can use:
-
-    if (bit_depth < 8)
-       png_set_packswap(png_ptr);
-
-Finally, you can write your own transformation function if none of
-the existing ones meets your needs.  This is done by setting a callback
-with
-
-    png_set_read_user_transform_fn(png_ptr,
-        read_transform_fn);
-
-You must supply the function
-
-    void read_transform_fn(png_structp png_ptr, png_row_infop
-        row_info, png_bytep data)
-
-See pngtest.c for a working example.  Your function will be called
-after all of the other transformations have been processed.  Take care with
-interlaced images if you do the interlace yourself - the width of the row is the
-width in 'row_info', not the overall image width.
-
-If supported, libpng provides two information routines that you can use to find
-where you are in processing the image:
-
-   png_get_current_pass_number(png_structp png_ptr);
-   png_get_current_row_number(png_structp png_ptr);
-
-Don't try using these outside a transform callback - firstly they are only
-supported if user transforms are supported, secondly they may well return
-unexpected results unless the row is actually being processed at the moment they
-are called.
-
-With interlaced
-images the value returned is the row in the input sub-image image.  Use
-PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
-find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
-
-The discussion of interlace handling above contains more information on how to
-use these values.
-
-You can also set up a pointer to a user structure for use by your
-callback function, and you can inform libpng that your transform
-function will change the number of channels or bit depth with the
-function
-
-    png_set_user_transform_info(png_ptr, user_ptr,
-        user_depth, user_channels);
-
-The user's application, not libpng, is responsible for allocating and
-freeing any memory required for the user structure.
-
-You can retrieve the pointer via the function
-png_get_user_transform_ptr().  For example:
-
-    voidp read_user_transform_ptr =
-        png_get_user_transform_ptr(png_ptr);
-
-The last thing to handle is interlacing; this is covered in detail below,
-but you must call the function here if you want libpng to handle expansion
-of the interlaced image.
-
-    number_of_passes = png_set_interlace_handling(png_ptr);
-
-After setting the transformations, libpng can update your png_info
-structure to reflect any transformations you've requested with this
-call.
-
-    png_read_update_info(png_ptr, info_ptr);
-
-This is most useful to update the info structure's rowbytes
-field so you can use it to allocate your image memory.  This function
-will also update your palette with the correct screen_gamma and
-background if these have been given with the calls above.  You may
-only call png_read_update_info() once with a particular info_ptr.
-
-After you call png_read_update_info(), you can allocate any
-memory you need to hold the image.  The row data is simply
-raw byte data for all forms of images.  As the actual allocation
-varies among applications, no example will be given.  If you
-are allocating one large chunk, you will need to build an
-array of pointers to each row, as it will be needed for some
-of the functions below.
-
-Remember: Before you call png_read_update_info(), the png_get_*()
-functions return the values corresponding to the original PNG image.
-After you call png_read_update_info the values refer to the image
-that libpng will output.  Consequently you must call all the png_set_
-functions before you call png_read_update_info().  This is particularly
-important for png_set_interlace_handling() - if you are going to call
-png_read_update_info() you must call png_set_interlace_handling() before
-it unless you want to receive interlaced output.
-
-Reading image data
-
-After you've allocated memory, you can read the image data.
-The simplest way to do this is in one function call.  If you are
-allocating enough memory to hold the whole image, you can just
-call png_read_image() and libpng will read in all the image data
-and put it in the memory area supplied.  You will need to pass in
-an array of pointers to each row.
-
-This function automatically handles interlacing, so you don't
-need to call png_set_interlace_handling() (unless you call
-png_read_update_info()) or call this function multiple times, or any
-of that other stuff necessary with png_read_rows().
-
-   png_read_image(png_ptr, row_pointers);
-
-where row_pointers is:
-
-   png_bytep row_pointers[height];
-
-You can point to void or char or whatever you use for pixels.
-
-If you don't want to read in the whole image at once, you can
-use png_read_rows() instead.  If there is no interlacing (check
-interlace_type == PNG_INTERLACE_NONE), this is simple:
-
-    png_read_rows(png_ptr, row_pointers, NULL,
-        number_of_rows);
-
-where row_pointers is the same as in the png_read_image() call.
-
-If you are doing this just one row at a time, you can do this with
-a single row_pointer instead of an array of row_pointers:
-
-    png_bytep row_pointer = row;
-    png_read_row(png_ptr, row_pointer, NULL);
-
-If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
-get somewhat harder.  The only current (PNG Specification version 1.2)
-interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
-a somewhat complicated 2D interlace scheme, known as Adam7, that
-breaks down an image into seven smaller images of varying size, based
-on an 8x8 grid.  This number is defined (from libpng 1.5) as
-PNG_INTERLACE_ADAM7_PASSES in png.h
-
-libpng can fill out those images or it can give them to you "as is".
-It is almost always better to have libpng handle the interlacing for you.
-If you want the images filled out, there are two ways to do that.  The one
-mentioned in the PNG specification is to expand each pixel to cover
-those pixels that have not been read yet (the "rectangle" method).
-This results in a blocky image for the first pass, which gradually
-smooths out as more pixels are read.  The other method is the "sparkle"
-method, where pixels are drawn only in their final locations, with the
-rest of the image remaining whatever colors they were initialized to
-before the start of the read.  The first method usually looks better,
-but tends to be slower, as there are more pixels to put in the rows.
-
-If, as is likely, you want libpng to expand the images, call this before
-calling png_start_read_image() or png_read_update_info():
-
-    if (interlace_type == PNG_INTERLACE_ADAM7)
-       number_of_passes
-           = png_set_interlace_handling(png_ptr);
-
-This will return the number of passes needed.  Currently, this is seven,
-but may change if another interlace type is added.  This function can be
-called even if the file is not interlaced, where it will return one pass.
-You then need to read the whole image 'number_of_passes' times.  Each time
-will distribute the pixels from the current pass to the correct place in
-the output image, so you need to supply the same rows to png_read_rows in
-each pass.
-
-If you are not going to display the image after each pass, but are
-going to wait until the entire image is read in, use the sparkle
-effect.  This effect is faster and the end result of either method
-is exactly the same.  If you are planning on displaying the image
-after each pass, the "rectangle" effect is generally considered the
-better looking one.
-
-If you only want the "sparkle" effect, just call png_read_rows() as
-normal, with the third parameter NULL.  Make sure you make pass over
-the image number_of_passes times, and you don't change the data in the
-rows between calls.  You can change the locations of the data, just
-not the data.  Each pass only writes the pixels appropriate for that
-pass, and assumes the data from previous passes is still valid.
-
-    png_read_rows(png_ptr, row_pointers, NULL,
-        number_of_rows);
-
-If you only want the first effect (the rectangles), do the same as
-before except pass the row buffer in the third parameter, and leave
-the second parameter NULL.
-
-    png_read_rows(png_ptr, NULL, row_pointers,
-        number_of_rows);
-
-If you don't want libpng to handle the interlacing details, just call
-png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
-Each of the images is a valid image by itself, however you will almost
-certainly need to distribute the pixels from each sub-image to the
-correct place.  This is where everything gets very tricky.
-
-If you want to retrieve the separate images you must pass the correct
-number of rows to each successive call of png_read_rows().  The calculation
-gets pretty complicated for small images, where some sub-images may
-not even exist because either their width or height ends up zero.
-libpng provides two macros to help you in 1.5 and later versions:
-
-   png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
-   png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
-
-Respectively these tell you the width and height of the sub-image
-corresponding to the numbered pass.  'pass' is in in the range 0 to 6 -
-this can be confusing because the specification refers to the same passes
-as 1 to 7!  Be careful, you must check both the width and height before
-calling png_read_rows() and not call it for that pass if either is zero.
-
-You can, of course, read each sub-image row by row.  If you want to
-produce optimal code to make a pixel-by-pixel transformation of an
-interlaced image this is the best approach; read each row of each pass,
-transform it, and write it out to a new interlaced image.
-
-If you want to de-interlace the image yourself libpng provides further
-macros to help that tell you where to place the pixels in the output image.
-Because the interlacing scheme is rectangular - sub-image pixels are always
-arranged on a rectangular grid - all you need to know for each pass is the
-starting column and row in the output image of the first pixel plus the
-spacing between each pixel.  As of libpng 1.5 there are four macros to
-retrieve this information:
-
-   png_uint_32 x = PNG_PASS_START_COL(pass);
-   png_uint_32 y = PNG_PASS_START_ROW(pass);
-   png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
-   png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
-
-These allow you to write the obvious loop:
-
-   png_uint_32 input_y = 0;
-   png_uint_32 output_y = PNG_PASS_START_ROW(pass);
-
-   while (output_y < output_image_height)
-   {
-      png_uint_32 input_x = 0;
-      png_uint_32 output_x = PNG_PASS_START_COL(pass);
-
-      while (output_x < output_image_width)
-      {
-         image[output_y][output_x] =
-             subimage[pass][input_y][input_x++];
-
-         output_x += xStep;
-      }
-
-      ++input_y;
-      output_y += yStep;
-   }
-
-Notice that the steps between successive output rows and columns are
-returned as shifts.  This is possible because the pixels in the subimages
-are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
-image.  In practice you may need to directly calculate the output coordinate
-given an input coordinate.  libpng provides two further macros for this
-purpose:
-
-   png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
-   png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
-
-Finally a pair of macros are provided to tell you if a particular image
-row or column appears in a given pass:
-
-   int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
-   int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
-
-Bear in mind that you will probably also need to check the width and height
-of the pass in addition to the above to be sure the pass even exists!
-
-With any luck you are convinced by now that you don't want to do your own
-interlace handling.  In reality normally the only good reason for doing this
-is if you are processing PNG files on a pixel-by-pixel basis and don't want
-to load the whole file into memory when it is interlaced.
-
-libpng includes a test program, pngvalid, that illustrates reading and
-writing of interlaced images.  If you can't get interlacing to work in your
-code and don't want to leave it to libpng (the recommended approach), see
-how pngvalid.c does it.
-
-Finishing a sequential read
-
-After you are finished reading the image through the
-low-level interface, you can finish reading the file.  If you are
-interested in comments or time, which may be stored either before or
-after the image data, you should pass the separate png_info struct if
-you want to keep the comments from before and after the image
-separate.
-
-    png_infop end_info = png_create_info_struct(png_ptr);
-
-    if (!end_info)
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-           (png_infopp)NULL);
-       return (ERROR);
-    }
-
-   png_read_end(png_ptr, end_info);
-
-If you are not interested, you should still call png_read_end()
-but you can pass NULL, avoiding the need to create an end_info structure.
-
-   png_read_end(png_ptr, (png_infop)NULL);
-
-If you don't call png_read_end(), then your file pointer will be
-left pointing to the first chunk after the last IDAT, which is probably
-not what you want if you expect to read something beyond the end of
-the PNG datastream.
-
-When you are done, you can free all memory allocated by libpng like this:
-
-   png_destroy_read_struct(&png_ptr, &info_ptr,
-       &end_info);
-
-or, if you didn't create an end_info structure,
-
-   png_destroy_read_struct(&png_ptr, &info_ptr,
-       (png_infopp)NULL);
-
-It is also possible to individually free the info_ptr members that
-point to libpng-allocated storage with the following function:
-
-    png_free_data(png_ptr, info_ptr, mask, seq)
-
-    mask - identifies data to be freed, a mask
-           containing the bitwise OR of one or
-           more of
-             PNG_FREE_PLTE, PNG_FREE_TRNS,
-             PNG_FREE_HIST, PNG_FREE_ICCP,
-             PNG_FREE_PCAL, PNG_FREE_ROWS,
-             PNG_FREE_SCAL, PNG_FREE_SPLT,
-             PNG_FREE_TEXT, PNG_FREE_UNKN,
-           or simply PNG_FREE_ALL
-
-    seq  - sequence number of item to be freed
-           (-1 for all items)
-
-This function may be safely called when the relevant storage has
-already been freed, or has not yet been allocated, or was allocated
-by the user and not by libpng,  and will in those cases do nothing.
-The "seq" parameter is ignored if only one item of the selected data
-type, such as PLTE, is allowed.  If "seq" is not -1, and multiple items
-are allowed for the data type identified in the mask, such as text or
-sPLT, only the n'th item in the structure is freed, where n is "seq".
-
-The default behavior is only to free data that was allocated internally
-by libpng.  This can be changed, so that libpng will not free the data,
-or so that it will free data that was allocated by the user with png_malloc()
-or png_zalloc() and passed in via a png_set_*() function, with
-
-    png_data_freer(png_ptr, info_ptr, freer, mask)
-
-    freer  - one of
-               PNG_DESTROY_WILL_FREE_DATA
-               PNG_SET_WILL_FREE_DATA
-               PNG_USER_WILL_FREE_DATA
-
-    mask   - which data elements are affected
-             same choices as in png_free_data()
-
-This function only affects data that has already been allocated.
-You can call this function after reading the PNG data but before calling
-any png_set_*() functions, to control whether the user or the png_set_*()
-function is responsible for freeing any existing data that might be present,
-and again after the png_set_*() functions to control whether the user
-or png_destroy_*() is supposed to free the data.  When the user assumes
-responsibility for libpng-allocated data, the application must use
-png_free() to free it, and when the user transfers responsibility to libpng
-for data that the user has allocated, the user must have used png_malloc()
-or png_zalloc() to allocate it.
-
-If you allocated your row_pointers in a single block, as suggested above in
-the description of the high level read interface, you must not transfer
-responsibility for freeing it to the png_set_rows or png_read_destroy function,
-because they would also try to free the individual row_pointers[i].
-
-If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
-separately, do not transfer responsibility for freeing text_ptr to libpng,
-because when libpng fills a png_text structure it combines these members with
-the key member, and png_free_data() will free only text_ptr.key.  Similarly,
-if you transfer responsibility for free'ing text_ptr from libpng to your
-application, your application must not separately free those members.
-
-The png_free_data() function will turn off the "valid" flag for anything
-it frees.  If you need to turn the flag off for a chunk that was freed by
-your application instead of by libpng, you can use
-
-    png_set_invalid(png_ptr, info_ptr, mask);
-
-    mask - identifies the chunks to be made invalid,
-           containing the bitwise OR of one or
-           more of
-             PNG_INFO_gAMA, PNG_INFO_sBIT,
-             PNG_INFO_cHRM, PNG_INFO_PLTE,
-             PNG_INFO_tRNS, PNG_INFO_bKGD,
-             PNG_INFO_hIST, PNG_INFO_pHYs,
-             PNG_INFO_oFFs, PNG_INFO_tIME,
-             PNG_INFO_pCAL, PNG_INFO_sRGB,
-             PNG_INFO_iCCP, PNG_INFO_sPLT,
-             PNG_INFO_sCAL, PNG_INFO_IDAT
-
-For a more compact example of reading a PNG image, see the file example.c.
-
-Reading PNG files progressively
-
-The progressive reader is slightly different then the non-progressive
-reader.  Instead of calling png_read_info(), png_read_rows(), and
-png_read_end(), you make one call to png_process_data(), which calls
-callbacks when it has the info, a row, or the end of the image.  You
-set up these callbacks with png_set_progressive_read_fn().  You don't
-have to worry about the input/output functions of libpng, as you are
-giving the library the data directly in png_process_data().  I will
-assume that you have read the section on reading PNG files above,
-so I will only highlight the differences (although I will show
-all of the code).
-
-png_structp png_ptr;
-png_infop info_ptr;
-
- /*  An example code fragment of how you would
-     initialize the progressive reader in your
-     application. */
- int
- initialize_png_reader()
- {
-    png_ptr = png_create_read_struct
-        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-         user_error_fn, user_warning_fn);
-
-    if (!png_ptr)
-        return (ERROR);
-
-    info_ptr = png_create_info_struct(png_ptr);
-
-    if (!info_ptr)
-    {
-       png_destroy_read_struct(&png_ptr,
-          (png_infopp)NULL, (png_infopp)NULL);
-       return (ERROR);
-    }
-
-    if (setjmp(png_jmpbuf(png_ptr)))
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-          (png_infopp)NULL);
-       return (ERROR);
-    }
-
-    /* This one's new.  You can provide functions
-       to be called when the header info is valid,
-       when each row is completed, and when the image
-       is finished.  If you aren't using all functions,
-       you can specify NULL parameters.  Even when all
-       three functions are NULL, you need to call
-       png_set_progressive_read_fn().  You can use
-       any struct as the user_ptr (cast to a void pointer
-       for the function call), and retrieve the pointer
-       from inside the callbacks using the function
-
-          png_get_progressive_ptr(png_ptr);
-
-       which will return a void pointer, which you have
-       to cast appropriately.
-     */
-    png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
-        info_callback, row_callback, end_callback);
-
-    return 0;
- }
-
- /* A code fragment that you call as you receive blocks
-   of data */
- int
- process_data(png_bytep buffer, png_uint_32 length)
- {
-    if (setjmp(png_jmpbuf(png_ptr)))
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-           (png_infopp)NULL);
-       return (ERROR);
-    }
-
-    /* This one's new also.  Simply give it a chunk
-       of data from the file stream (in order, of
-       course).  On machines with segmented memory
-       models machines, don't give it any more than
-       64K.  The library seems to run fine with sizes
-       of 4K. Although you can give it much less if
-       necessary (I assume you can give it chunks of
-       1 byte, I haven't tried less then 256 bytes
-       yet).  When this function returns, you may
-       want to display any rows that were generated
-       in the row callback if you don't already do
-       so there.
-     */
-    png_process_data(png_ptr, info_ptr, buffer, length);
-
-    /* At this point you can call png_process_data_skip if
-       you want to handle data the library will skip yourself;
-       it simply returns the number of bytes to skip (and stops
-       libpng skipping that number of bytes on the next
-       png_process_data call).
-    return 0;
- }
-
- /* This function is called (as set by
-    png_set_progressive_read_fn() above) when enough data
-    has been supplied so all of the header has been
-    read.
- */
- void
- info_callback(png_structp png_ptr, png_infop info)
- {
-    /* Do any setup here, including setting any of
-       the transformations mentioned in the Reading
-       PNG files section.  For now, you _must_ call
-       either png_start_read_image() or
-       png_read_update_info() after all the
-       transformations are set (even if you don't set
-       any).  You may start getting rows before
-       png_process_data() returns, so this is your
-       last chance to prepare for that.
-
-       This is where you turn on interlace handling,
-       assuming you don't want to do it yourself.
-
-       If you need to you can stop the processing of
-       your original input data at this point by calling
-       png_process_data_pause.  This returns the number
-       of unprocessed bytes from the last png_process_data
-       call - it is up to you to ensure that the next call
-       sees these bytes again.  If you don't want to bother
-       with this you can get libpng to cache the unread
-       bytes by setting the 'save' parameter (see png.h) but
-       then libpng will have to copy the data internally.
-     */
- }
-
- /* This function is called when each row of image
-    data is complete */
- void
- row_callback(png_structp png_ptr, png_bytep new_row,
-    png_uint_32 row_num, int pass)
- {
-    /* If the image is interlaced, and you turned
-       on the interlace handler, this function will
-       be called for every row in every pass.  Some
-       of these rows will not be changed from the
-       previous pass.  When the row is not changed,
-       the new_row variable will be NULL.  The rows
-       and passes are called in order, so you don't
-       really need the row_num and pass, but I'm
-       supplying them because it may make your life
-       easier.
-
-       If you did not turn on interlace handling then
-       the callback is called for each row of each
-       sub-image when the image is interlaced.  In this
-       case 'row_num' is the row in the sub-image, not
-       the row in the output image as it is in all other
-       cases.
-
-       For the non-NULL rows of interlaced images when
-       you have switched on libpng interlace handling,
-       you must call png_progressive_combine_row()
-       passing in the row and the old row.  You can
-       call this function for NULL rows (it will just
-       return) and for non-interlaced images (it just
-       does the memcpy for you) if it will make the
-       code easier.  Thus, you can just do this for
-       all cases if you switch on interlace handling;
-     */
-
-        png_progressive_combine_row(png_ptr, old_row,
-          new_row);
-
-    /* where old_row is what was displayed for
-       previously for the row.  Note that the first
-       pass (pass == 0, really) will completely cover
-       the old row, so the rows do not have to be
-       initialized.  After the first pass (and only
-       for interlaced images), you will have to pass
-       the current row, and the function will combine
-       the old row and the new row.
-
-       You can also call png_process_data_pause in this
-       callback - see above.
-    */
- }
-
- void
- end_callback(png_structp png_ptr, png_infop info)
- {
-    /* This function is called after the whole image
-       has been read, including any chunks after the
-       image (up to and including the IEND).  You
-       will usually have the same info chunk as you
-       had in the header, although some data may have
-       been added to the comments and time fields.
-
-       Most people won't do much here, perhaps setting
-       a flag that marks the image as finished.
-     */
- }
-
-
-
-IV. Writing
-
-Much of this is very similar to reading.  However, everything of
-importance is repeated here, so you won't have to constantly look
-back up in the reading section to understand writing.
-
-Setup
-
-You will want to do the I/O initialization before you get into libpng,
-so if it doesn't work, you don't have anything to undo. If you are not
-using the standard I/O functions, you will need to replace them with
-custom writing functions.  See the discussion under Customizing libpng.
-
-    FILE *fp = fopen(file_name, "wb");
-
-    if (!fp)
-       return (ERROR);
-
-Next, png_struct and png_info need to be allocated and initialized.
-As these can be both relatively large, you may not want to store these
-on the stack, unless you have stack space to spare.  Of course, you
-will want to check if they return NULL.  If you are also reading,
-you won't want to name your read structure and your write structure
-both "png_ptr"; you can call them anything you like, such as
-"read_ptr" and "write_ptr".  Look at pngtest.c, for example.
-
-    png_structp png_ptr = png_create_write_struct
-       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-        user_error_fn, user_warning_fn);
-
-    if (!png_ptr)
-       return (ERROR);
-
-    png_infop info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr)
-    {
-       png_destroy_write_struct(&png_ptr,
-           (png_infopp)NULL);
-       return (ERROR);
-    }
-
-If you want to use your own memory allocation routines,
-define PNG_USER_MEM_SUPPORTED and use
-png_create_write_struct_2() instead of png_create_write_struct():
-
-    png_structp png_ptr = png_create_write_struct_2
-       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-        user_error_fn, user_warning_fn, (png_voidp)
-        user_mem_ptr, user_malloc_fn, user_free_fn);
-
-After you have these structures, you will need to set up the
-error handling.  When libpng encounters an error, it expects to
-longjmp() back to your routine.  Therefore, you will need to call
-setjmp() and pass the png_jmpbuf(png_ptr).  If you
-write the file from different routines, you will need to update
-the png_jmpbuf(png_ptr) every time you enter a new routine that will
-call a png_*() function.  See your documentation of setjmp/longjmp
-for your compiler for more information on setjmp/longjmp.  See
-the discussion on libpng error handling in the Customizing Libpng
-section below for more information on the libpng error handling.
-
-    if (setjmp(png_jmpbuf(png_ptr)))
-    {
-    png_destroy_write_struct(&png_ptr, &info_ptr);
-       fclose(fp);
-       return (ERROR);
-    }
-    ...
-    return;
-
-If you would rather avoid the complexity of setjmp/longjmp issues,
-you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT() which defaults to abort().
-
-You can #define PNG_ABORT() to a function that does something
-more useful than abort(), as long as your function does not
-return.
-
-Now you need to set up the output code.  The default for libpng is to
-use the C function fwrite().  If you use this, you will need to pass a
-valid FILE * in the function png_init_io().  Be sure that the file is
-opened in binary mode.  Again, if you wish to handle writing data in
-another way, see the discussion on libpng I/O handling in the Customizing
-Libpng section below.
-
-    png_init_io(png_ptr, fp);
-
-If you are embedding your PNG into a datastream such as MNG, and don't
-want libpng to write the 8-byte signature, or if you have already
-written the signature in your application, use
-
-    png_set_sig_bytes(png_ptr, 8);
-
-to inform libpng that it should not write a signature.
-
-Write callbacks
-
-At this point, you can set up a callback function that will be
-called after each row has been written, which you can use to control
-a progress meter or the like.  It's demonstrated in pngtest.c.
-You must supply a function
-
-    void write_row_callback(png_structp png_ptr, png_uint_32 row,
-       int pass);
-    {
-      /* put your code here */
-    }
-
-(You can give it another name that you like instead of "write_row_callback")
-
-To inform libpng about your function, use
-
-    png_set_write_status_fn(png_ptr, write_row_callback);
-
-When this function is called the row has already been completely processed and
-it has also been written out.  The 'row' and 'pass' refer to the next row to be
-handled.  For the
-non-interlaced case the row that was just handled is simply one less than the
-passed in row number, and pass will always be 0.  For the interlaced case the
-same applies unless the row value is 0, in which case the row just handled was
-the last one from one of the preceding passes.  Because interlacing may skip a
-pass you cannot be sure that the preceding pass is just 'pass-1', if you really
-need to know what the last pass is record (row,pass) from the callback and use
-the last recorded value each time.
-
-As with the user transform you can find the output row using the
-PNG_ROW_FROM_PASS_ROW macro.
-
-You now have the option of modifying how the compression library will
-run.  The following functions are mainly for testing, but may be useful
-in some cases, like if you need to write PNG files extremely fast and
-are willing to give up some compression, or if you want to get the
-maximum possible compression at the expense of slower writing.  If you
-have no special needs in this area, let the library do what it wants by
-not calling this function at all, as it has been tuned to deliver a good
-speed/compression ratio. The second parameter to png_set_filter() is
-the filter method, for which the only valid values are 0 (as of the
-July 1999 PNG specification, version 1.2) or 64 (if you are writing
-a PNG datastream that is to be embedded in a MNG datastream).  The third
-parameter is a flag that indicates which filter type(s) are to be tested
-for each scanline.  See the PNG specification for details on the specific
-filter types.
-
-
-    /* turn on or off filtering, and/or choose
-       specific filters.  You can use either a single
-       PNG_FILTER_VALUE_NAME or the bitwise OR of one
-       or more PNG_FILTER_NAME masks.
-     */
-    png_set_filter(png_ptr, 0,
-       PNG_FILTER_NONE  | PNG_FILTER_VALUE_NONE |
-       PNG_FILTER_SUB   | PNG_FILTER_VALUE_SUB  |
-       PNG_FILTER_UP    | PNG_FILTER_VALUE_UP   |
-       PNG_FILTER_AVG   | PNG_FILTER_VALUE_AVG  |
-       PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
-       PNG_ALL_FILTERS);
-
-If an application wants to start and stop using particular filters during
-compression, it should start out with all of the filters (to ensure that
-the previous row of pixels will be stored in case it's needed later),
-and then add and remove them after the start of compression.
-
-If you are writing a PNG datastream that is to be embedded in a MNG
-datastream, the second parameter can be either 0 or 64.
-
-The png_set_compression_*() functions interface to the zlib compression
-library, and should mostly be ignored unless you really know what you are
-doing.  The only generally useful call is png_set_compression_level()
-which changes how much time zlib spends on trying to compress the image
-data.  See the Compression Library (zlib.h and algorithm.txt, distributed
-with zlib) for details on the compression levels.
-
-    #include zlib.h
-
-    /* Set the zlib compression level */
-    png_set_compression_level(png_ptr,
-        Z_BEST_COMPRESSION);
-
-    /* Set other zlib parameters for compressing IDAT */
-    png_set_compression_mem_level(png_ptr, 8);
-    png_set_compression_strategy(png_ptr,
-        Z_DEFAULT_STRATEGY);
-    png_set_compression_window_bits(png_ptr, 15);
-    png_set_compression_method(png_ptr, 8);
-    png_set_compression_buffer_size(png_ptr, 8192)
-
-    /* Set zlib parameters for text compression
-     * If you don't call these, the parameters
-     * fall back on those defined for IDAT chunks
-     */
-    png_set_text_compression_mem_level(png_ptr, 8);
-    png_set_text_compression_strategy(png_ptr,
-        Z_DEFAULT_STRATEGY);
-    png_set_text_compression_window_bits(png_ptr, 15);
-    png_set_text_compression_method(png_ptr, 8);
-
-Setting the contents of info for output
-
-You now need to fill in the png_info structure with all the data you
-wish to write before the actual image.  Note that the only thing you
-are allowed to write after the image is the text chunks and the time
-chunk (as of PNG Specification 1.2, anyway).  See png_write_end() and
-the latest PNG specification for more information on that.  If you
-wish to write them before the image, fill them in now, and flag that
-data as being valid.  If you want to wait until after the data, don't
-fill them until png_write_end().  For all the fields in png_info and
-their data types, see png.h.  For explanations of what the fields
-contain, see the PNG specification.
-
-Some of the more important parts of the png_info are:
-
-    png_set_IHDR(png_ptr, info_ptr, width, height,
-       bit_depth, color_type, interlace_type,
-       compression_type, filter_method)
-
-    width          - holds the width of the image
-                     in pixels (up to 2^31).
-
-    height         - holds the height of the image
-                     in pixels (up to 2^31).
-
-    bit_depth      - holds the bit depth of one of the
-                     image channels.
-                     (valid values are 1, 2, 4, 8, 16
-                     and depend also on the
-                     color_type.  See also significant
-                     bits (sBIT) below).
-
-    color_type     - describes which color/alpha
-                     channels are present.
-                     PNG_COLOR_TYPE_GRAY
-                        (bit depths 1, 2, 4, 8, 16)
-                     PNG_COLOR_TYPE_GRAY_ALPHA
-                        (bit depths 8, 16)
-                     PNG_COLOR_TYPE_PALETTE
-                        (bit depths 1, 2, 4, 8)
-                     PNG_COLOR_TYPE_RGB
-                        (bit_depths 8, 16)
-                     PNG_COLOR_TYPE_RGB_ALPHA
-                        (bit_depths 8, 16)
-
-                     PNG_COLOR_MASK_PALETTE
-                     PNG_COLOR_MASK_COLOR
-                     PNG_COLOR_MASK_ALPHA
-
-    interlace_type - PNG_INTERLACE_NONE or
-                     PNG_INTERLACE_ADAM7
-
-    compression_type - (must be
-                     PNG_COMPRESSION_TYPE_DEFAULT)
-
-    filter_method  - (must be PNG_FILTER_TYPE_DEFAULT
-                     or, if you are writing a PNG to
-                     be embedded in a MNG datastream,
-                     can also be
-                     PNG_INTRAPIXEL_DIFFERENCING)
-
-If you call png_set_IHDR(), the call must appear before any of the
-other png_set_*() functions, because they might require access to some of
-the IHDR settings.  The remaining png_set_*() functions can be called
-in any order.
-
-If you wish, you can reset the compression_type, interlace_type, or
-filter_method later by calling png_set_IHDR() again; if you do this, the
-width, height, bit_depth, and color_type must be the same in each call.
-
-    png_set_PLTE(png_ptr, info_ptr, palette,
-       num_palette);
-
-    palette        - the palette for the file
-                     (array of png_color)
-    num_palette    - number of entries in the palette
-
-    png_set_gAMA(png_ptr, info_ptr, file_gamma);
-    png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
-
-    file_gamma     - the gamma at which the image was
-                     created (PNG_INFO_gAMA)
-
-    int_file_gamma - 100,000 times the gamma at which
-                     the image was created
-
-    png_set_cHRM(png_ptr, info_ptr,  white_x, white_y, red_x, red_y,
-                     green_x, green_y, blue_x, blue_y)
-    png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X,
-                     green_Y, green_Z, blue_X, blue_Y, blue_Z)
-    png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y,
-                     int_red_x, int_red_y, int_green_x, int_green_y,
-                     int_blue_x, int_blue_y)
-    png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y,
-                     int_red_Z, int_green_X, int_green_Y, int_green_Z,
-                     int_blue_X, int_blue_Y, int_blue_Z)
-
-    {white,red,green,blue}_{x,y}
-                     A color space encoding specified using the chromaticities
-                     of the end points and the white point.
-
-    {red,green,blue}_{X,Y,Z}
-                     A color space encoding specified using the encoding end
-                     points - the CIE tristimulus specification of the intended
-                     color of the red, green and blue channels in the PNG RGB
-                     data.  The white point is simply the sum of the three end
-                     points.
-
-    png_set_sRGB(png_ptr, info_ptr, srgb_intent);
-
-    srgb_intent    - the rendering intent
-                     (PNG_INFO_sRGB) The presence of
-                     the sRGB chunk means that the pixel
-                     data is in the sRGB color space.
-                     This chunk also implies specific
-                     values of gAMA and cHRM.  Rendering
-                     intent is the CSS-1 property that
-                     has been defined by the International
-                     Color Consortium
-                     (http://www.color.org).
-                     It can be one of
-                     PNG_sRGB_INTENT_SATURATION,
-                     PNG_sRGB_INTENT_PERCEPTUAL,
-                     PNG_sRGB_INTENT_ABSOLUTE, or
-                     PNG_sRGB_INTENT_RELATIVE.
-
-
-    png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
-       srgb_intent);
-
-    srgb_intent    - the rendering intent
-                     (PNG_INFO_sRGB) The presence of the
-                     sRGB chunk means that the pixel
-                     data is in the sRGB color space.
-                     This function also causes gAMA and
-                     cHRM chunks with the specific values
-                     that are consistent with sRGB to be
-                     written.
-
-    png_set_iCCP(png_ptr, info_ptr, name, compression_type,
-                       profile, proflen);
-
-    name             - The profile name.
-
-    compression_type - The compression type; always
-                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
-                       You may give NULL to this argument to
-                       ignore it.
-
-    profile          - International Color Consortium color
-                       profile data. May contain NULs.
-
-    proflen          - length of profile data in bytes.
-
-    png_set_sBIT(png_ptr, info_ptr, sig_bit);
-
-    sig_bit        - the number of significant bits for
-                     (PNG_INFO_sBIT) each of the gray, red,
-                     green, and blue channels, whichever are
-                     appropriate for the given color type
-                     (png_color_16)
-
-    png_set_tRNS(png_ptr, info_ptr, trans_alpha,
-       num_trans, trans_color);
-
-    trans_alpha    - array of alpha (transparency)
-                     entries for palette (PNG_INFO_tRNS)
-
-    num_trans      - number of transparent entries
-                     (PNG_INFO_tRNS)
-
-    trans_color    - graylevel or color sample values
-                     (in order red, green, blue) of the
-                     single transparent color for
-                     non-paletted images (PNG_INFO_tRNS)
-
-    png_set_hIST(png_ptr, info_ptr, hist);
-
-    hist           - histogram of palette (array of
-                     png_uint_16) (PNG_INFO_hIST)
-
-    png_set_tIME(png_ptr, info_ptr, mod_time);
-
-    mod_time       - time image was last modified
-                     (PNG_VALID_tIME)
-
-    png_set_bKGD(png_ptr, info_ptr, background);
-
-    background     - background color (of type
-                     png_color_16p) (PNG_VALID_bKGD)
-
-    png_set_text(png_ptr, info_ptr, text_ptr, num_text);
-
-    text_ptr       - array of png_text holding image
-                     comments
-
-    text_ptr[i].compression - type of compression used
-                 on "text" PNG_TEXT_COMPRESSION_NONE
-                           PNG_TEXT_COMPRESSION_zTXt
-                           PNG_ITXT_COMPRESSION_NONE
-                           PNG_ITXT_COMPRESSION_zTXt
-    text_ptr[i].key   - keyword for comment.  Must contain
-                 1-79 characters.
-    text_ptr[i].text  - text comments for current
-                         keyword.  Can be NULL or empty.
-    text_ptr[i].text_length - length of text string,
-                 after decompression, 0 for iTXt
-    text_ptr[i].itxt_length - length of itxt string,
-                 after decompression, 0 for tEXt/zTXt
-    text_ptr[i].lang  - language of comment (NULL or
-                         empty for unknown).
-    text_ptr[i].translated_keyword  - keyword in UTF-8 (NULL
-                         or empty for unknown).
-
-    Note that the itxt_length, lang, and lang_key
-    members of the text_ptr structure only exist when the
-    library is built with iTXt chunk support.  Prior to
-    libpng-1.4.0 the library was built by default without
-    iTXt support. Also note that when iTXt is supported,
-    they contain NULL pointers when the "compression"
-    field contains PNG_TEXT_COMPRESSION_NONE or
-    PNG_TEXT_COMPRESSION_zTXt.
-
-    num_text       - number of comments
-
-    png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
-       num_spalettes);
-
-    palette_ptr    - array of png_sPLT_struct structures
-                     to be added to the list of palettes
-                     in the info structure.
-    num_spalettes  - number of palette structures to be
-                     added.
-
-    png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
-        unit_type);
-
-    offset_x  - positive offset from the left
-                     edge of the screen
-
-    offset_y  - positive offset from the top
-                     edge of the screen
-
-    unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
-
-    png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
-        unit_type);
-
-    res_x       - pixels/unit physical resolution
-                  in x direction
-
-    res_y       - pixels/unit physical resolution
-                  in y direction
-
-    unit_type   - PNG_RESOLUTION_UNKNOWN,
-                  PNG_RESOLUTION_METER
-
-    png_set_sCAL(png_ptr, info_ptr, unit, width, height)
-
-    unit        - physical scale units (an integer)
-
-    width       - width of a pixel in physical scale units
-
-    height      - height of a pixel in physical scale units
-                  (width and height are doubles)
-
-    png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
-
-    unit        - physical scale units (an integer)
-
-    width       - width of a pixel in physical scale units
-                  expressed as a string
-
-    height      - height of a pixel in physical scale units
-                 (width and height are strings like "2.54")
-
-    png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
-       num_unknowns)
-
-    unknowns          - array of png_unknown_chunk
-                        structures holding unknown chunks
-    unknowns[i].name  - name of unknown chunk
-    unknowns[i].data  - data of unknown chunk
-    unknowns[i].size  - size of unknown chunk's data
-    unknowns[i].location - position to write chunk in file
-                           0: do not write chunk
-                           PNG_HAVE_IHDR: before PLTE
-                           PNG_HAVE_PLTE: before IDAT
-                           PNG_AFTER_IDAT: after IDAT
-
-The "location" member is set automatically according to
-what part of the output file has already been written.
-You can change its value after calling png_set_unknown_chunks()
-as demonstrated in pngtest.c.  Within each of the "locations",
-the chunks are sequenced according to their position in the
-structure (that is, the value of "i", which is the order in which
-the chunk was either read from the input file or defined with
-png_set_unknown_chunks).
-
-A quick word about text and num_text.  text is an array of png_text
-structures.  num_text is the number of valid structures in the array.
-Each png_text structure holds a language code, a keyword, a text value,
-and a compression type.
-
-The compression types have the same valid numbers as the compression
-types of the image data.  Currently, the only valid number is zero.
-However, you can store text either compressed or uncompressed, unlike
-images, which always have to be compressed.  So if you don't want the
-text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
-Because tEXt and zTXt chunks don't have a language field, if you
-specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
-any language code or translated keyword will not be written out.
-
-Until text gets around a few hundred bytes, it is not worth compressing it.
-After the text has been written out to the file, the compression type
-is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
-so that it isn't written out again at the end (in case you are calling
-png_write_end() with the same struct).
-
-The keywords that are given in the PNG Specification are:
-
-    Title            Short (one line) title or
-                     caption for image
-
-    Author           Name of image's creator
-
-    Description      Description of image (possibly long)
-
-    Copyright        Copyright notice
-
-    Creation Time    Time of original image creation
-                     (usually RFC 1123 format, see below)
-
-    Software         Software used to create the image
-
-    Disclaimer       Legal disclaimer
-
-    Warning          Warning of nature of content
-
-    Source           Device used to create the image
-
-    Comment          Miscellaneous comment; conversion
-                     from other image format
-
-The keyword-text pairs work like this.  Keywords should be short
-simple descriptions of what the comment is about.  Some typical
-keywords are found in the PNG specification, as is some recommendations
-on keywords.  You can repeat keywords in a file.  You can even write
-some text before the image and some after.  For example, you may want
-to put a description of the image before the image, but leave the
-disclaimer until after, so viewers working over modem connections
-don't have to wait for the disclaimer to go over the modem before
-they start seeing the image.  Finally, keywords should be full
-words, not abbreviations.  Keywords and text are in the ISO 8859-1
-(Latin-1) character set (a superset of regular ASCII) and can not
-contain NUL characters, and should not contain control or other
-unprintable characters.  To make the comments widely readable, stick
-with basic ASCII, and avoid machine specific character set extensions
-like the IBM-PC character set.  The keyword must be present, but
-you can leave off the text string on non-compressed pairs.
-Compressed pairs must have a text string, as only the text string
-is compressed anyway, so the compression would be meaningless.
-
-PNG supports modification time via the png_time structure.  Two
-conversion routines are provided, png_convert_from_time_t() for
-time_t and png_convert_from_struct_tm() for struct tm.  The
-time_t routine uses gmtime().  You don't have to use either of
-these, but if you wish to fill in the png_time structure directly,
-you should provide the time in universal time (GMT) if possible
-instead of your local time.  Note that the year number is the full
-year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
-that months start with 1.
-
-If you want to store the time of the original image creation, you should
-use a plain tEXt chunk with the "Creation Time" keyword.  This is
-necessary because the "creation time" of a PNG image is somewhat vague,
-depending on whether you mean the PNG file, the time the image was
-created in a non-PNG format, a still photo from which the image was
-scanned, or possibly the subject matter itself.  In order to facilitate
-machine-readable dates, it is recommended that the "Creation Time"
-tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
-although this isn't a requirement.  Unlike the tIME chunk, the
-"Creation Time" tEXt chunk is not expected to be automatically changed
-by the software.  To facilitate the use of RFC 1123 dates, a function
-png_convert_to_rfc1123(png_timep) is provided to convert from PNG
-time to an RFC 1123 format string.
-
-Writing unknown chunks
-
-You can use the png_set_unknown_chunks function to queue up chunks
-for writing.  You give it a chunk name, raw data, and a size; that's
-all there is to it.  The chunks will be written by the next following
-png_write_info_before_PLTE, png_write_info, or png_write_end function.
-Any chunks previously read into the info structure's unknown-chunk
-list will also be written out in a sequence that satisfies the PNG
-specification's ordering rules.
-
-The high-level write interface
-
-At this point there are two ways to proceed; through the high-level
-write interface, or through a sequence of low-level write operations.
-You can use the high-level interface if your image data is present
-in the info structure.  All defined output
-transformations are permitted, enabled by the following masks.
-
-    PNG_TRANSFORM_IDENTITY      No transformation
-    PNG_TRANSFORM_PACKING       Pack 1, 2 and 4-bit samples
-    PNG_TRANSFORM_PACKSWAP      Change order of packed
-                                pixels to LSB first
-    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
-    PNG_TRANSFORM_SHIFT         Normalize pixels to the
-                                sBIT depth
-    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
-                                to BGRA
-    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
-                                to AG
-    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
-                                to transparency
-    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
-    PNG_TRANSFORM_STRIP_FILLER        Strip out filler
-                                      bytes (deprecated).
-    PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
-                                      filler bytes
-    PNG_TRANSFORM_STRIP_FILLER_AFTER  Strip out trailing
-                                      filler bytes
-
-If you have valid image data in the info structure (you can use
-png_set_rows() to put image data in the info structure), simply do this:
-
-    png_write_png(png_ptr, info_ptr, png_transforms, NULL)
-
-where png_transforms is an integer containing the bitwise OR of some set of
-transformation flags.  This call is equivalent to png_write_info(),
-followed the set of transformations indicated by the transform mask,
-then png_write_image(), and finally png_write_end().
-
-(The final parameter of this call is not yet used.  Someday it might point
-to transformation parameters required by some future output transform.)
-
-You must use png_transforms and not call any png_set_transform() functions
-when you use png_write_png().
-
-The low-level write interface
-
-If you are going the low-level route instead, you are now ready to
-write all the file information up to the actual image data.  You do
-this with a call to png_write_info().
-
-    png_write_info(png_ptr, info_ptr);
-
-Note that there is one transformation you may need to do before
-png_write_info().  In PNG files, the alpha channel in an image is the
-level of opacity.  If your data is supplied as a level of transparency,
-you can invert the alpha channel before you write it, so that 0 is
-fully transparent and 255 (in 8-bit or paletted images) or 65535
-(in 16-bit images) is fully opaque, with
-
-    png_set_invert_alpha(png_ptr);
-
-This must appear before png_write_info() instead of later with the
-other transformations because in the case of paletted images the tRNS
-chunk data has to be inverted before the tRNS chunk is written.  If
-your image is not a paletted image, the tRNS data (which in such cases
-represents a single color to be rendered as transparent) won't need to
-be changed, and you can safely do this transformation after your
-png_write_info() call.
-
-If you need to write a private chunk that you want to appear before
-the PLTE chunk when PLTE is present, you can write the PNG info in
-two steps, and insert code to write your own chunk between them:
-
-    png_write_info_before_PLTE(png_ptr, info_ptr);
-    png_set_unknown_chunks(png_ptr, info_ptr, ...);
-    png_write_info(png_ptr, info_ptr);
-
-After you've written the file information, you can set up the library
-to handle any special transformations of the image data.  The various
-ways to transform the data will be described in the order that they
-should occur.  This is important, as some of these change the color
-type and/or bit depth of the data, and some others only work on
-certain color types and bit depths.  Even though each transformation
-checks to see if it has data that it can do something with, you should
-make sure to only enable a transformation if it will be valid for the
-data.  For example, don't swap red and blue on grayscale data.
-
-PNG files store RGB pixels packed into 3 or 6 bytes.  This code tells
-the library to strip input data that has 4 or 8 bytes per pixel down
-to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
-bytes per pixel).
-
-    png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
-
-where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
-PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
-is stored XRGB or RGBX.
-
-PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
-they can, resulting in, for example, 8 pixels per byte for 1 bit files.
-If the data is supplied at 1 pixel per byte, use this code, which will
-correctly pack the pixels into a single byte:
-
-    png_set_packing(png_ptr);
-
-PNG files reduce possible bit depths to 1, 2, 4, 8, and 16.  If your
-data is of another bit depth, you can write an sBIT chunk into the
-file so that decoders can recover the original data if desired.
-
-    /* Set the true bit depth of the image data */
-    if (color_type & PNG_COLOR_MASK_COLOR)
-    {
-       sig_bit.red = true_bit_depth;
-       sig_bit.green = true_bit_depth;
-       sig_bit.blue = true_bit_depth;
-    }
-
-    else
-    {
-       sig_bit.gray = true_bit_depth;
-    }
-
-    if (color_type & PNG_COLOR_MASK_ALPHA)
-    {
-       sig_bit.alpha = true_bit_depth;
-    }
-
-    png_set_sBIT(png_ptr, info_ptr, &sig_bit);
-
-If the data is stored in the row buffer in a bit depth other than
-one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
-this will scale the values to appear to be the correct bit depth as
-is required by PNG.
-
-    png_set_shift(png_ptr, &sig_bit);
-
-PNG files store 16-bit pixels in network byte order (big-endian,
-ie. most significant bits first).  This code would be used if they are
-supplied the other way (little-endian, i.e. least significant bits
-first, the way PCs store them):
-
-    if (bit_depth > 8)
-       png_set_swap(png_ptr);
-
-If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
-need to change the order the pixels are packed into bytes, you can use:
-
-    if (bit_depth < 8)
-       png_set_packswap(png_ptr);
-
-PNG files store 3 color pixels in red, green, blue order.  This code
-would be used if they are supplied as blue, green, red:
-
-    png_set_bgr(png_ptr);
-
-PNG files describe monochrome as black being zero and white being
-one. This code would be used if the pixels are supplied with this reversed
-(black being one and white being zero):
-
-    png_set_invert_mono(png_ptr);
-
-Finally, you can write your own transformation function if none of
-the existing ones meets your needs.  This is done by setting a callback
-with
-
-    png_set_write_user_transform_fn(png_ptr,
-       write_transform_fn);
-
-You must supply the function
-
-    void write_transform_fn(png_structp png_ptr, png_row_infop
-       row_info, png_bytep data)
-
-See pngtest.c for a working example.  Your function will be called
-before any of the other transformations are processed.  If supported
-libpng also supplies an information routine that may be called from
-your callback:
-
-   png_get_current_row_number(png_ptr);
-   png_get_current_pass_number(png_ptr);
-
-This returns the current row passed to the transform.  With interlaced
-images the value returned is the row in the input sub-image image.  Use
-PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
-find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
-
-The discussion of interlace handling above contains more information on how to
-use these values.
-
-You can also set up a pointer to a user structure for use by your
-callback function.
-
-    png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
-
-The user_channels and user_depth parameters of this function are ignored
-when writing; you can set them to zero as shown.
-
-You can retrieve the pointer via the function png_get_user_transform_ptr().
-For example:
-
-    voidp write_user_transform_ptr =
-       png_get_user_transform_ptr(png_ptr);
-
-It is possible to have libpng flush any pending output, either manually,
-or automatically after a certain number of lines have been written.  To
-flush the output stream a single time call:
-
-    png_write_flush(png_ptr);
-
-and to have libpng flush the output stream periodically after a certain
-number of scanlines have been written, call:
-
-    png_set_flush(png_ptr, nrows);
-
-Note that the distance between rows is from the last time png_write_flush()
-was called, or the first row of the image if it has never been called.
-So if you write 50 lines, and then png_set_flush 25, it will flush the
-output on the next scanline, and every 25 lines thereafter, unless
-png_write_flush() is called before 25 more lines have been written.
-If nrows is too small (less than about 10 lines for a 640 pixel wide
-RGB image) the image compression may decrease noticeably (although this
-may be acceptable for real-time applications).  Infrequent flushing will
-only degrade the compression performance by a few percent over images
-that do not use flushing.
-
-Writing the image data
-
-That's it for the transformations.  Now you can write the image data.
-The simplest way to do this is in one function call.  If you have the
-whole image in memory, you can just call png_write_image() and libpng
-will write the image.  You will need to pass in an array of pointers to
-each row.  This function automatically handles interlacing, so you don't
-need to call png_set_interlace_handling() or call this function multiple
-times, or any of that other stuff necessary with png_write_rows().
-
-    png_write_image(png_ptr, row_pointers);
-
-where row_pointers is:
-
-    png_byte *row_pointers[height];
-
-You can point to void or char or whatever you use for pixels.
-
-If you don't want to write the whole image at once, you can
-use png_write_rows() instead.  If the file is not interlaced,
-this is simple:
-
-    png_write_rows(png_ptr, row_pointers,
-       number_of_rows);
-
-row_pointers is the same as in the png_write_image() call.
-
-If you are just writing one row at a time, you can do this with
-a single row_pointer instead of an array of row_pointers:
-
-    png_bytep row_pointer = row;
-
-    png_write_row(png_ptr, row_pointer);
-
-When the file is interlaced, things can get a good deal more complicated.
-The only currently (as of the PNG Specification version 1.2, dated July
-1999) defined interlacing scheme for PNG files is the "Adam7" interlace
-scheme, that breaks down an image into seven smaller images of varying
-size.  libpng will build these images for you, or you can do them
-yourself.  If you want to build them yourself, see the PNG specification
-for details of which pixels to write when.
-
-If you don't want libpng to handle the interlacing details, just
-use png_set_interlace_handling() and call png_write_rows() the
-correct number of times to write all the sub-images
-(png_set_interlace_handling() returns the number of sub-images.)
-
-If you want libpng to build the sub-images, call this before you start
-writing any rows:
-
-    number_of_passes = png_set_interlace_handling(png_ptr);
-
-This will return the number of passes needed.  Currently, this is seven,
-but may change if another interlace type is added.
-
-Then write the complete image number_of_passes times.
-
-    png_write_rows(png_ptr, row_pointers, number_of_rows);
-
-Think carefully before you write an interlaced image.  Typically code that
-reads such images reads all the image data into memory, uncompressed, before
-doing any processing.  Only code that can display an image on the fly can
-take advantage of the interlacing and even then the image has to be exactly
-the correct size for the output device, because scaling an image requires
-adjacent pixels and these are not available until all the passes have been
-read.
-
-If you do write an interlaced image you will hardly ever need to handle
-the interlacing yourself.  Call png_set_interlace_handling() and use the
-approach described above.
-
-The only time it is conceivable that you will really need to write an
-interlaced image pass-by-pass is when you have read one pass by pass and
-made some pixel-by-pixel transformation to it, as described in the read
-code above.  In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
-to determine the size of each sub-image in turn and simply write the rows
-you obtained from the read code.
-
-Finishing a sequential write
-
-After you are finished writing the image, you should finish writing
-the file.  If you are interested in writing comments or time, you should
-pass an appropriately filled png_info pointer.  If you are not interested,
-you can pass NULL.
-
-    png_write_end(png_ptr, info_ptr);
-
-When you are done, you can free all memory used by libpng like this:
-
-    png_destroy_write_struct(&png_ptr, &info_ptr);
-
-It is also possible to individually free the info_ptr members that
-point to libpng-allocated storage with the following function:
-
-    png_free_data(png_ptr, info_ptr, mask, seq)
-
-    mask  - identifies data to be freed, a mask
-            containing the bitwise OR of one or
-            more of
-              PNG_FREE_PLTE, PNG_FREE_TRNS,
-              PNG_FREE_HIST, PNG_FREE_ICCP,
-              PNG_FREE_PCAL, PNG_FREE_ROWS,
-              PNG_FREE_SCAL, PNG_FREE_SPLT,
-              PNG_FREE_TEXT, PNG_FREE_UNKN,
-            or simply PNG_FREE_ALL
-
-    seq   - sequence number of item to be freed
-            (-1 for all items)
-
-This function may be safely called when the relevant storage has
-already been freed, or has not yet been allocated, or was allocated
-by the user  and not by libpng,  and will in those cases do nothing.
-The "seq" parameter is ignored if only one item of the selected data
-type, such as PLTE, is allowed.  If "seq" is not -1, and multiple items
-are allowed for the data type identified in the mask, such as text or
-sPLT, only the n'th item in the structure is freed, where n is "seq".
-
-If you allocated data such as a palette that you passed in to libpng
-with png_set_*, you must not free it until just before the call to
-png_destroy_write_struct().
-
-The default behavior is only to free data that was allocated internally
-by libpng.  This can be changed, so that libpng will not free the data,
-or so that it will free data that was allocated by the user with png_malloc()
-or png_zalloc() and passed in via a png_set_*() function, with
-
-    png_data_freer(png_ptr, info_ptr, freer, mask)
-
-    freer  - one of
-               PNG_DESTROY_WILL_FREE_DATA
-               PNG_SET_WILL_FREE_DATA
-               PNG_USER_WILL_FREE_DATA
-
-    mask   - which data elements are affected
-             same choices as in png_free_data()
-
-For example, to transfer responsibility for some data from a read structure
-to a write structure, you could use
-
-    png_data_freer(read_ptr, read_info_ptr,
-       PNG_USER_WILL_FREE_DATA,
-       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
-
-    png_data_freer(write_ptr, write_info_ptr,
-       PNG_DESTROY_WILL_FREE_DATA,
-       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
-
-thereby briefly reassigning responsibility for freeing to the user but
-immediately afterwards reassigning it once more to the write_destroy
-function.  Having done this, it would then be safe to destroy the read
-structure and continue to use the PLTE, tRNS, and hIST data in the write
-structure.
-
-This function only affects data that has already been allocated.
-You can call this function before calling after the png_set_*() functions
-to control whether the user or png_destroy_*() is supposed to free the data.
-When the user assumes responsibility for libpng-allocated data, the
-application must use
-png_free() to free it, and when the user transfers responsibility to libpng
-for data that the user has allocated, the user must have used png_malloc()
-or png_zalloc() to allocate it.
-
-If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
-separately, do not transfer responsibility for freeing text_ptr to libpng,
-because when libpng fills a png_text structure it combines these members with
-the key member, and png_free_data() will free only text_ptr.key.  Similarly,
-if you transfer responsibility for free'ing text_ptr from libpng to your
-application, your application must not separately free those members.
-For a more compact example of writing a PNG image, see the file example.c.
-
-V. Modifying/Customizing libpng:
-
-There are two issues here.  The first is changing how libpng does
-standard things like memory allocation, input/output, and error handling.
-The second deals with more complicated things like adding new chunks,
-adding new transformations, and generally changing how libpng works.
-Both of those are compile-time issues; that is, they are generally
-determined at the time the code is written, and there is rarely a need
-to provide the user with a means of changing them.
-
-Memory allocation, input/output, and error handling
-
-All of the memory allocation, input/output, and error handling in libpng
-goes through callbacks that are user-settable.  The default routines are
-in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively.  To change
-these functions, call the appropriate png_set_*_fn() function.
-
-Memory allocation is done through the functions png_malloc(), png_calloc(),
-and png_free().  These currently just call the standard C functions.
-png_calloc() calls png_malloc() and then clears the newly
-allocated memory to zero.  There is limited support for certain systems
-with segmented memory architectures and the types of pointers declared by
-png.h match this; you will have to use appropriate pointers in your
-application.  Since it is
-unlikely that the method of handling memory allocation on a platform
-will change between applications, these functions must be modified in
-the library at compile time.  If you prefer to use a different method
-of allocating and freeing data, you can use png_create_read_struct_2() or
-png_create_write_struct_2() to register your own functions as described
-above.  These functions also provide a void pointer that can be retrieved
-via
-
-    mem_ptr=png_get_mem_ptr(png_ptr);
-
-Your replacement memory functions must have prototypes as follows:
-
-    png_voidp malloc_fn(png_structp png_ptr,
-       png_alloc_size_t size);
-
-    void free_fn(png_structp png_ptr, png_voidp ptr);
-
-Your malloc_fn() must return NULL in case of failure.  The png_malloc()
-function will normally call png_error() if it receives a NULL from the
-system memory allocator or from your replacement malloc_fn().
-
-Your free_fn() will never be called with a NULL ptr, since libpng's
-png_free() checks for NULL before calling free_fn().
-
-Input/Output in libpng is done through png_read() and png_write(),
-which currently just call fread() and fwrite().  The FILE * is stored in
-png_struct and is initialized via png_init_io().  If you wish to change
-the method of I/O, the library supplies callbacks that you can set
-through the function png_set_read_fn() and png_set_write_fn() at run
-time, instead of calling the png_init_io() function.  These functions
-also provide a void pointer that can be retrieved via the function
-png_get_io_ptr().  For example:
-
-    png_set_read_fn(png_structp read_ptr,
-        voidp read_io_ptr, png_rw_ptr read_data_fn)
-
-    png_set_write_fn(png_structp write_ptr,
-        voidp write_io_ptr, png_rw_ptr write_data_fn,
-        png_flush_ptr output_flush_fn);
-
-    voidp read_io_ptr = png_get_io_ptr(read_ptr);
-    voidp write_io_ptr = png_get_io_ptr(write_ptr);
-
-The replacement I/O functions must have prototypes as follows:
-
-    void user_read_data(png_structp png_ptr,
-        png_bytep data, png_size_t length);
-
-    void user_write_data(png_structp png_ptr,
-        png_bytep data, png_size_t length);
-
-    void user_flush_data(png_structp png_ptr);
-
-The user_read_data() function is responsible for detecting and
-handling end-of-data errors.
-
-Supplying NULL for the read, write, or flush functions sets them back
-to using the default C stream functions, which expect the io_ptr to
-point to a standard *FILE structure.  It is probably a mistake
-to use NULL for one of write_data_fn and output_flush_fn but not both
-of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
-It is an error to read from a write stream, and vice versa.
-
-Error handling in libpng is done through png_error() and png_warning().
-Errors handled through png_error() are fatal, meaning that png_error()
-should never return to its caller.  Currently, this is handled via
-setjmp() and longjmp() (unless you have compiled libpng with
-PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
-but you could change this to do things like exit() if you should wish,
-as long as your function does not return.
-
-On non-fatal errors, png_warning() is called
-to print a warning message, and then control returns to the calling code.
-By default png_error() and png_warning() print a message on stderr via
-fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
-(because you don't want the messages) or PNG_NO_STDIO defined (because
-fprintf() isn't available).  If you wish to change the behavior of the error
-functions, you will need to set up your own message callbacks.  These
-functions are normally supplied at the time that the png_struct is created.
-It is also possible to redirect errors and warnings to your own replacement
-functions after png_create_*_struct() has been called by calling:
-
-    png_set_error_fn(png_structp png_ptr,
-        png_voidp error_ptr, png_error_ptr error_fn,
-        png_error_ptr warning_fn);
-
-    png_voidp error_ptr = png_get_error_ptr(png_ptr);
-
-If NULL is supplied for either error_fn or warning_fn, then the libpng
-default function will be used, calling fprintf() and/or longjmp() if a
-problem is encountered.  The replacement error functions should have
-parameters as follows:
-
-    void user_error_fn(png_structp png_ptr,
-        png_const_charp error_msg);
-
-    void user_warning_fn(png_structp png_ptr,
-        png_const_charp warning_msg);
-
-The motivation behind using setjmp() and longjmp() is the C++ throw and
-catch exception handling methods.  This makes the code much easier to write,
-as there is no need to check every return code of every function call.
-However, there are some uncertainties about the status of local variables
-after a longjmp, so the user may want to be careful about doing anything
-after setjmp returns non-zero besides returning itself.  Consult your
-compiler documentation for more details.  For an alternative approach, you
-may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net),
-which is illustrated in pngvalid.c and in contrib/visupng.
-
-Custom chunks
-
-If you need to read or write custom chunks, you may need to get deeper
-into the libpng code.  The library now has mechanisms for storing
-and writing chunks of unknown type; you can even declare callbacks
-for custom chunks.  However, this may not be good enough if the
-library code itself needs to know about interactions between your
-chunk and existing `intrinsic' chunks.
-
-If you need to write a new intrinsic chunk, first read the PNG
-specification. Acquire a first level of understanding of how it works.
-Pay particular attention to the sections that describe chunk names,
-and look at how other chunks were designed, so you can do things
-similarly.  Second, check out the sections of libpng that read and
-write chunks.  Try to find a chunk that is similar to yours and use
-it as a template.  More details can be found in the comments inside
-the code.  It is best to handle private or unknown chunks in a generic method,
-via callback functions, instead of by modifying libpng functions. This
-is illustrated in pngtest.c, which uses a callback function to handle a
-private "vpAg" chunk and the new "sTER" chunk, which are both unknown to
-libpng.
-
-If you wish to write your own transformation for the data, look through
-the part of the code that does the transformations, and check out some of
-the simpler ones to get an idea of how they work.  Try to find a similar
-transformation to the one you want to add and copy off of it.  More details
-can be found in the comments inside the code itself.
-
-Configuring for 16-bit platforms
-
-You will want to look into zconf.h to tell zlib (and thus libpng) that
-it cannot allocate more then 64K at a time.  Even if you can, the memory
-won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.
-
-Configuring for DOS
-
-For DOS users who only have access to the lower 640K, you will
-have to limit zlib's memory usage via a png_set_compression_mem_level()
-call.  See zlib.h or zconf.h in the zlib library for more information.
-
-Configuring for Medium Model
-
-Libpng's support for medium model has been tested on most of the popular
-compilers.  Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
-defined, and FAR gets defined to far in pngconf.h, and you should be
-all set.  Everything in the library (except for zlib's structure) is
-expecting far data.  You must use the typedefs with the p or pp on
-the end for pointers (or at least look at them and be careful).  Make
-note that the rows of data are defined as png_bytepp, which is
-an "unsigned char far * far *".
-
-Configuring for gui/windowing platforms:
-
-You will need to write new error and warning functions that use the GUI
-interface, as described previously, and set them to be the error and
-warning functions at the time that png_create_*_struct() is called,
-in order to have them available during the structure initialization.
-They can be changed later via png_set_error_fn().  On some compilers,
-you may also have to change the memory allocators (png_malloc, etc.).
-
-Configuring for compiler xxx:
-
-All includes for libpng are in pngconf.h.  If you need to add, change
-or delete an include, this is the place to do it.
-The includes that are not needed outside libpng are placed in pngpriv.h,
-which is only used by the routines inside libpng itself.
-The files in libpng proper only include pngpriv.h and png.h, which
-in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
-As of libpng-1.5.0, pngpriv.h also includes three other private header
-files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
-that previously appeared in the public headers.
-
-Configuring zlib:
-
-There are special functions to configure the compression.  Perhaps the
-most useful one changes the compression level, which currently uses
-input compression values in the range 0 - 9.  The library normally
-uses the default compression level (Z_DEFAULT_COMPRESSION = 6).  Tests
-have shown that for a large majority of images, compression values in
-the range 3-6 compress nearly as well as higher levels, and do so much
-faster.  For online applications it may be desirable to have maximum speed
-(Z_BEST_SPEED = 1).  With versions of zlib after v0.99, you can also
-specify no compression (Z_NO_COMPRESSION = 0), but this would create
-files larger than just storing the raw bitmap.  You can specify the
-compression level by calling:
-
-    #include zlib.h
-    png_set_compression_level(png_ptr, level);
-
-Another useful one is to reduce the memory level used by the library.
-The memory level defaults to 8, but it can be lowered if you are
-short on memory (running DOS, for example, where you only have 640K).
-Note that the memory level does have an effect on compression; among
-other things, lower levels will result in sections of incompressible
-data being emitted in smaller stored blocks, with a correspondingly
-larger relative overhead of up to 15% in the worst case.
-
-    #include zlib.h
-    png_set_compression_mem_level(png_ptr, level);
-
-The other functions are for configuring zlib.  They are not recommended
-for normal use and may result in writing an invalid PNG file.  See
-zlib.h for more information on what these mean.
-
-    #include zlib.h
-    png_set_compression_strategy(png_ptr,
-        strategy);
-
-    png_set_compression_window_bits(png_ptr,
-        window_bits);
-
-    png_set_compression_method(png_ptr, method);
-
-    png_set_compression_buffer_size(png_ptr, size);
-
-As of libpng version 1.5.4, additional APIs became
-available to set these separately for non-IDAT
-compressed chunks such as zTXt, iTXt, and iCCP:
-
-    #include zlib.h
-    #if PNG_LIBPNG_VER <= 10504
-    png_set_text_compression_level(png_ptr, level);
-
-    png_set_text_compression_mem_level(png_ptr, level);
-
-    png_set_text_compression_strategy(png_ptr,
-        strategy);
-
-    png_set_text_compression_window_bits(png_ptr,
-        window_bits);
-
-    png_set_text_compression_method(png_ptr, method);
-    #endif
-
-Controlling row filtering
-
-If you want to control whether libpng uses filtering or not, which
-filters are used, and how it goes about picking row filters, you
-can call one of these functions.  The selection and configuration
-of row filters can have a significant impact on the size and
-encoding speed and a somewhat lesser impact on the decoding speed
-of an image.  Filtering is enabled by default for RGB and grayscale
-images (with and without alpha), but not for paletted images nor
-for any images with bit depths less than 8 bits/pixel.
-
-The 'method' parameter sets the main filtering method, which is
-currently only '0' in the PNG 1.2 specification.  The 'filters'
-parameter sets which filter(s), if any, should be used for each
-scanline.  Possible values are PNG_ALL_FILTERS and PNG_NO_FILTERS
-to turn filtering on and off, respectively.
-
-Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
-PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
-ORed together with '|' to specify one or more filters to use.
-These filters are described in more detail in the PNG specification.
-If you intend to change the filter type during the course of writing
-the image, you should start with flags set for all of the filters
-you intend to use so that libpng can initialize its internal
-structures appropriately for all of the filter types.  (Note that this
-means the first row must always be adaptively filtered, because libpng
-currently does not allocate the filter buffers until png_write_row()
-is called for the first time.)
-
-    filters = PNG_FILTER_NONE | PNG_FILTER_SUB
-              PNG_FILTER_UP | PNG_FILTER_AVG |
-              PNG_FILTER_PAETH | PNG_ALL_FILTERS;
-
-    png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
-       filters);
-              The second parameter can also be
-              PNG_INTRAPIXEL_DIFFERENCING if you are
-              writing a PNG to be embedded in a MNG
-              datastream.  This parameter must be the
-              same as the value of filter_method used
-              in png_set_IHDR().
-
-It is also possible to influence how libpng chooses from among the
-available filters.  This is done in one or both of two ways - by
-telling it how important it is to keep the same filter for successive
-rows, and by telling it the relative computational costs of the filters.
-
-    double weights[3] = {1.5, 1.3, 1.1},
-       costs[PNG_FILTER_VALUE_LAST] =
-       {1.0, 1.3, 1.3, 1.5, 1.7};
-
-    png_set_filter_heuristics(png_ptr,
-       PNG_FILTER_HEURISTIC_WEIGHTED, 3,
-       weights, costs);
-
-The weights are multiplying factors that indicate to libpng that the
-row filter should be the same for successive rows unless another row filter
-is that many times better than the previous filter.  In the above example,
-if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a
-"sum of absolute differences" 1.5 x 1.3 times higher than other filters
-and still be chosen, while the NONE filter could have a sum 1.1 times
-higher than other filters and still be chosen.  Unspecified weights are
-taken to be 1.0, and the specified weights should probably be declining
-like those above in order to emphasize recent filters over older filters.
-
-The filter costs specify for each filter type a relative decoding cost
-to be considered when selecting row filters.  This means that filters
-with higher costs are less likely to be chosen over filters with lower
-costs, unless their "sum of absolute differences" is that much smaller.
-The costs do not necessarily reflect the exact computational speeds of
-the various filters, since this would unduly influence the final image
-size.
-
-Note that the numbers above were invented purely for this example and
-are given only to help explain the function usage.  Little testing has
-been done to find optimum values for either the costs or the weights.
-
-Removing unwanted object code
-
-There are a bunch of #define's in pngconf.h that control what parts of
-libpng are compiled.  All the defines end in _SUPPORTED.  If you are
-never going to use a capability, you can change the #define to #undef
-before recompiling libpng and save yourself code and data space, or
-you can turn off individual capabilities with defines that begin with
-PNG_NO_.
-
-In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
-
-You can also turn all of the transforms and ancillary chunk capabilities
-off en masse with compiler directives that define
-PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
-or all four,
-along with directives to turn on any of the capabilities that you do
-want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the extra
-transformations but still leave the library fully capable of reading
-and writing PNG files with all known public chunks. Use of the
-PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
-that is incapable of reading or writing ancillary chunks.  If you are
-not using the progressive reading capability, you can turn that off
-with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
-capability, which you'll still have).
-
-All the reading and writing specific code are in separate files, so the
-linker should only grab the files it needs.  However, if you want to
-make sure, or if you are building a stand alone library, all the
-reading files start with "pngr" and all the writing files start with "pngw".
-The files that don't match either (like png.c, pngtrans.c, etc.)
-are used for both reading and writing, and always need to be included.
-The progressive reader is in pngpread.c
-
-If you are creating or distributing a dynamically linked library (a .so
-or DLL file), you should not remove or disable any parts of the library,
-as this will cause applications linked with different versions of the
-library to fail if they call functions not available in your library.
-The size of the library itself should not be an issue, because only
-those sections that are actually used will be loaded into memory.
-
-Requesting debug printout
-
-The macro definition PNG_DEBUG can be used to request debugging
-printout.  Set it to an integer value in the range 0 to 3.  Higher
-numbers result in increasing amounts of debugging information.  The
-information is printed to the "stderr" file, unless another file
-name is specified in the PNG_DEBUG_FILE macro definition.
-
-When PNG_DEBUG > 0, the following functions (macros) become available:
-
-   png_debug(level, message)
-   png_debug1(level, message, p1)
-   png_debug2(level, message, p1, p2)
-
-in which "level" is compared to PNG_DEBUG to decide whether to print
-the message, "message" is the formatted string to be printed,
-and p1 and p2 are parameters that are to be embedded in the string
-according to printf-style formatting directives.  For example,
-
-   png_debug1(2, "foo=%d\n", foo);
-
-is expanded to
-
-   if (PNG_DEBUG > 2)
-      fprintf(PNG_DEBUG_FILE, "foo=%d\n", foo);
-
-When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
-can still use PNG_DEBUG to control your own debugging:
-
-   #ifdef PNG_DEBUG
-       fprintf(stderr, ...
-   #endif
-
-When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
-having level = 0 will be printed.  There aren't any such statements in
-this version of libpng, but if you insert some they will be printed.
-
-VI.  MNG support
-
-The MNG specification (available at http://www.libpng.org/pub/mng) allows
-certain extensions to PNG for PNG images that are embedded in MNG datastreams.
-Libpng can support some of these extensions.  To enable them, use the
-png_permit_mng_features() function:
-
-   feature_set = png_permit_mng_features(png_ptr, mask)
-
-   mask is a png_uint_32 containing the bitwise OR of the
-        features you want to enable.  These include
-        PNG_FLAG_MNG_EMPTY_PLTE
-        PNG_FLAG_MNG_FILTER_64
-        PNG_ALL_MNG_FEATURES
-
-   feature_set is a png_uint_32 that is the bitwise AND of
-      your mask with the set of MNG features that is
-      supported by the version of libpng that you are using.
-
-It is an error to use this function when reading or writing a standalone
-PNG file with the PNG 8-byte signature.  The PNG datastream must be wrapped
-in a MNG datastream.  As a minimum, it must have the MNG 8-byte signature
-and the MHDR and MEND chunks.  Libpng does not provide support for these
-or any other MNG chunks; your application must provide its own support for
-them.  You may wish to consider using libmng (available at
-http://www.libmng.com) instead.
-
-VII.  Changes to Libpng from version 0.88
-
-It should be noted that versions of libpng later than 0.96 are not
-distributed by the original libpng author, Guy Schalnat, nor by
-Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
-distributed versions 0.89 through 0.96, but rather by another member
-of the original PNG Group, Glenn Randers-Pehrson.  Guy and Andreas are
-still alive and well, but they have moved on to other things.
-
-The old libpng functions png_read_init(), png_write_init(),
-png_info_init(), png_read_destroy(), and png_write_destroy() have been
-moved to PNG_INTERNAL in version 0.95 to discourage their use.  These
-functions will be removed from libpng version 1.4.0.
-
-The preferred method of creating and initializing the libpng structures is
-via the png_create_read_struct(), png_create_write_struct(), and
-png_create_info_struct() because they isolate the size of the structures
-from the application, allow version error checking, and also allow the
-use of custom error handling routines during the initialization, which
-the old functions do not.  The functions png_read_destroy() and
-png_write_destroy() do not actually free the memory that libpng
-allocated for these structs, but just reset the data structures, so they
-can be used instead of png_destroy_read_struct() and
-png_destroy_write_struct() if you feel there is too much system overhead
-allocating and freeing the png_struct for each image read.
-
-Setting the error callbacks via png_set_message_fn() before
-png_read_init() as was suggested in libpng-0.88 is no longer supported
-because this caused applications that do not use custom error functions
-to fail if the png_ptr was not initialized to zero.  It is still possible
-to set the error callbacks AFTER png_read_init(), or to change them with
-png_set_error_fn(), which is essentially the same function, but with a new
-name to force compilation errors with applications that try to use the old
-method.
-
-Starting with version 1.0.7, you can find out which version of the library
-you are using at run-time:
-
-   png_uint_32 libpng_vn = png_access_version_number();
-
-The number libpng_vn is constructed from the major version, minor
-version with leading zero, and release number with leading zero,
-(e.g., libpng_vn for version 1.0.7 is 10007).
-
-Note that this function does not take a png_ptr, so you can call it
-before you've created one.
-
-You can also check which version of png.h you used when compiling your
-application:
-
-   png_uint_32 application_vn = PNG_LIBPNG_VER;
-
-VIII.  Changes to Libpng from version 1.0.x to 1.2.x
-
-Support for user memory management was enabled by default.  To
-accomplish this, the functions png_create_read_struct_2(),
-png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
-png_malloc_default(), and png_free_default() were added.
-
-Support for the iTXt chunk has been enabled by default as of
-version 1.2.41.
-
-Support for certain MNG features was enabled.
-
-Support for numbered error messages was added.  However, we never got
-around to actually numbering the error messages.  The function
-png_set_strip_error_numbers() was added (Note: the prototype for this
-function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
-builds of libpng-1.2.15.  It was restored in libpng-1.2.36).
-
-The png_malloc_warn() function was added at libpng-1.2.3.  This issues
-a png_warning and returns NULL instead of aborting when it fails to
-acquire the requested memory allocation.
-
-Support for setting user limits on image width and height was enabled
-by default.  The functions png_set_user_limits(), png_get_user_width_max(),
-and png_get_user_height_max() were added at libpng-1.2.6.
-
-The png_set_add_alpha() function was added at libpng-1.2.7.
-
-The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
-Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
-tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
-deprecated.
-
-A number of macro definitions in support of runtime selection of
-assembler code features (especially Intel MMX code support) were
-added at libpng-1.2.0:
-
-    PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
-    PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
-    PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
-    PNG_ASM_FLAG_MMX_READ_INTERLACE
-    PNG_ASM_FLAG_MMX_READ_FILTER_SUB
-    PNG_ASM_FLAG_MMX_READ_FILTER_UP
-    PNG_ASM_FLAG_MMX_READ_FILTER_AVG
-    PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
-    PNG_ASM_FLAGS_INITIALIZED
-    PNG_MMX_READ_FLAGS
-    PNG_MMX_FLAGS
-    PNG_MMX_WRITE_FLAGS
-    PNG_MMX_FLAGS
-
-We added the following functions in support of runtime
-selection of assembler code features:
-
-    png_get_mmx_flagmask()
-    png_set_mmx_thresholds()
-    png_get_asm_flags()
-    png_get_mmx_bitdepth_threshold()
-    png_get_mmx_rowbytes_threshold()
-    png_set_asm_flags()
-
-We replaced all of these functions with simple stubs in libpng-1.2.20,
-when the Intel assembler code was removed due to a licensing issue.
-
-These macros are deprecated:
-
-    PNG_READ_TRANSFORMS_NOT_SUPPORTED
-    PNG_PROGRESSIVE_READ_NOT_SUPPORTED
-    PNG_NO_SEQUENTIAL_READ_SUPPORTED
-    PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
-    PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
-    PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
-
-They have been replaced, respectively, by:
-
-    PNG_NO_READ_TRANSFORMS
-    PNG_NO_PROGRESSIVE_READ
-    PNG_NO_SEQUENTIAL_READ
-    PNG_NO_WRITE_TRANSFORMS
-    PNG_NO_READ_ANCILLARY_CHUNKS
-    PNG_NO_WRITE_ANCILLARY_CHUNKS
-
-PNG_MAX_UINT was replaced with PNG_UINT_31_MAX.  It has been
-deprecated since libpng-1.0.16 and libpng-1.2.6.
-
-The function
-    png_check_sig(sig, num)
-was replaced with
-    !png_sig_cmp(sig, 0, num)
-It has been deprecated since libpng-0.90.
-
-The function
-    png_set_gray_1_2_4_to_8()
-which also expands tRNS to alpha was replaced with
-    png_set_expand_gray_1_2_4_to_8()
-which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
-
-IX.  Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
-
-Private libpng prototypes and macro definitions were moved from
-png.h and pngconf.h into a new pngpriv.h header file.
-
-Functions png_set_benign_errors(), png_benign_error(), and
-png_chunk_benign_error() were added.
-
-Support for setting the maximum amount of memory that the application
-will allocate for reading chunks was added, as a security measure.
-The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
-were added to the library.
-
-We implemented support for I/O states by adding png_ptr member io_state
-and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
-
-We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
-input transforms.
-
-Checking for and reporting of errors in the IHDR chunk is more thorough.
-
-Support for global arrays was removed, to improve thread safety.
-
-Some obsolete/deprecated macros and functions have been removed.
-
-Typecasted NULL definitions such as
-   #define png_voidp_NULL            (png_voidp)NULL
-were eliminated.  If you used these in your application, just use
-NULL instead.
-
-The png_struct and info_struct members "trans" and "trans_values" were
-changed to "trans_alpha" and "trans_color", respectively.
-
-The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
-were removed.
-
-The PNG_1_0_X and PNG_1_2_X macros were eliminated.
-
-The PNG_LEGACY_SUPPORTED macro was eliminated.
-
-Many WIN32_WCE #ifdefs were removed.
-
-The functions png_read_init(info_ptr), png_write_init(info_ptr),
-png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
-have been removed.  They have been deprecated since libpng-0.95.
-
-The png_permit_empty_plte() was removed. It has been deprecated
-since libpng-1.0.9.  Use png_permit_mng_features() instead.
-
-We removed the obsolete stub functions png_get_mmx_flagmask(),
-png_set_mmx_thresholds(), png_get_asm_flags(),
-png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
-png_set_asm_flags(), and png_mmx_supported()
-
-We removed the obsolete png_check_sig(), png_memcpy_check(), and
-png_memset_check() functions.  Instead use !png_sig_cmp(), memcpy(),
-and memset(), respectively.
-
-The function png_set_gray_1_2_4_to_8() was removed. It has been
-deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
-png_set_expand_gray_1_2_4_to_8() because the former function also
-expanded any tRNS chunk to an alpha channel.
-
-Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32
-were added and are used by default instead of the corresponding
-functions. Unfortunately,
-from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
-function) incorrectly returned a value of type png_uint_32.
-
-We changed the prototype for png_malloc() from
-    png_malloc(png_structp png_ptr, png_uint_32 size)
-to
-    png_malloc(png_structp png_ptr, png_alloc_size_t size)
-
-This also applies to the prototype for the user replacement malloc_fn().
-
-The png_calloc() function was added and is used in place of
-of "png_malloc(); memset();" except in the case in png_read_png()
-where the array consists of pointers; in this case a "for" loop is used
-after the png_malloc() to set the pointers to NULL, to give robust.
-behavior in case the application runs out of memory part-way through
-the process.
-
-We changed the prototypes of png_get_compression_buffer_size() and
-png_set_compression_buffer_size() to work with png_size_t instead of
-png_uint_32.
-
-Support for numbered error messages was removed by default, since we
-never got around to actually numbering the error messages. The function
-png_set_strip_error_numbers() was removed from the library by default.
-
-The png_zalloc() and png_zfree() functions are no longer exported.
-The png_zalloc() function no longer zeroes out the memory that it
-allocates.
-
-Support for dithering was disabled by default in libpng-1.4.0, because
-it has not been well tested and doesn't actually "dither".
-The code was not
-removed, however, and could be enabled by building libpng with
-PNG_READ_DITHER_SUPPORTED defined.  In libpng-1.4.2, this support
-was reenabled, but the function was renamed png_set_quantize() to
-reflect more accurately what it actually does.  At the same time,
-the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
-PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED
-was renamed to PNG_READ_QUANTIZE_SUPPORTED.
-
-We removed the trailing '.' from the warning and error messages.
-
-X.  Changes to Libpng from version 1.4.x to 1.5.x
-
-From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
-function) incorrectly returned a value of type png_uint_32.
-
-Checking for invalid palette index on read or write was added at libpng
-1.5.10.  When an invalid index is found, libpng issues a benign error.
-This is enabled by default but can be disabled in each png_ptr with
-
-   png_set_check_for_invalid_index(png_ptr, allowed);
-
-      allowed  - one of
-                 0: disable
-                 1: enable
-
-A. Changes that affect users of libpng
-
-There are no substantial API changes between the non-deprecated parts of
-the 1.4.5 API and the 1.5.0 API, however the ability to directly access
-the main libpng control structures, png_struct and png_info, deprecated
-in earlier versions of libpng, has been completely removed from
-libpng 1.5.
-
-We no longer include zlib.h in png.h.  Applications that need access
-to information in zlib.h will need to add the '#include "zlib.h"'
-directive.  It does not matter whether it is placed prior to or after
-the '"#include png.h"' directive.
-
-We moved the png_strcpy(), png_strncpy(), png_strlen(), png_memcpy(),
-png_memcmp(), png_sprintf, and png_memcpy() macros into a private
-header file (pngpriv.h) that is not accessible to applications.
-
-In png_get_iCCP, the type of "profile" was changed from png_charpp
-to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep.
-
-There are changes of form in png.h, including new and changed macros to
-declare parts of the API.  Some API functions with arguments that are
-pointers to data not modified within the function have been corrected to
-declare these arguments with PNG_CONST.
-
-Much of the internal use of C macros to control the library build has also
-changed and some of this is visible in the exported header files, in
-particular the use of macros to control data and API elements visible
-during application compilation may require significant revision to
-application code.  (It is extremely rare for an application to do this.)
-
-Any program that compiled against libpng 1.4 and did not use deprecated
-features or access internal library structures should compile and work
-against libpng 1.5, except for the change in the prototype for
-png_get_iCCP() and png_set_iCCP() API functions mentioned above.
-
-libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of
-interlaced images.  The macros return the number of rows and columns in
-each pass and information that can be used to de-interlace and (if
-absolutely necessary) interlace an image.
-
-libpng 1.5.0 adds an API png_longjmp(png_ptr, value).  This API calls
-the application-provided png_longjmp_ptr on the internal, but application
-initialized, longjmp buffer.  It is provided as a convenience to avoid
-the need to use the png_jmpbuf macro, which had the unnecessary side
-effect of resetting the internal png_longjmp_ptr value.
-
-libpng 1.5.0 includes a complete fixed point API.  By default this is
-present along with the corresponding floating point API.  In general the
-fixed point API is faster and smaller than the floating point one because
-the PNG file format used fixed point, not floating point.  This applies
-even if the library uses floating point in internal calculations.  A new
-macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library
-uses floating point arithmetic (the default) or fixed point arithmetic
-internally for performance critical calculations such as gamma correction.
-In some cases, the gamma calculations may produce slightly different
-results.  This has changed the results in png_rgb_to_gray and in alpha
-composition (png_set_background for example). This applies even if the
-original image was already linear (gamma == 1.0) and, therefore, it is
-not necessary to linearize the image.  This is because libpng has *not*
-been changed to optimize that case correctly, yet.
-
-Fixed point support for the sCAL chunk comes with an important caveat;
-the sCAL specification uses a decimal encoding of floating point values
-and the accuracy of PNG fixed point values is insufficient for
-representation of these values. Consequently a "string" API
-(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
-arbitrary sCAL chunks in the absence of either the floating point API or
-internal floating point calculations.
-
-Applications no longer need to include the optional distribution header
-file pngusr.h or define the corresponding macros during application
-build in order to see the correct variant of the libpng API.  From 1.5.0
-application code can check for the corresponding _SUPPORTED macro:
-
-#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
-   /* code that uses the inch conversion APIs. */
-#endif
-
-This macro will only be defined if the inch conversion functions have been
-compiled into libpng.  The full set of macros, and whether or not support
-has been compiled in, are available in the header file pnglibconf.h.
-This header file is specific to the libpng build.  Notice that prior to
-1.5.0 the _SUPPORTED macros would always have the default definition unless
-reset by pngusr.h or by explicit settings on the compiler command line.
-These settings may produce compiler warnings or errors in 1.5.0 because
-of macro redefinition.
-
-From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
-function) incorrectly returned a value of type png_uint_32.  libpng 1.5.0
-is consistent with the implementation in 1.4.5 and 1.2.x (where the macro
-did not exist.)
-
-Applications can now choose whether to use these macros or to call the
-corresponding function by defining PNG_USE_READ_MACROS or
-PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
-only supported from 1.5.0 -defining PNG_NO_USE_READ_MACROS prior to 1.5.0
-will lead to a link failure.
-
-Prior to libpng-1.5.4, the zlib compressor used the same set of parameters
-when compressing the IDAT data and textual data such as zTXt and iCCP.
-In libpng-1.5.4 we reinitialized the zlib stream for each type of data.
-We added five png_set_text_*() functions for setting the parameters to
-use with textual data.
-
-Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
-option was off by default, and slightly inaccurate scaling occurred.
-This option can no longer be turned off, and the choice of accurate
-or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
-API for accurate scaling or the old png_set_strip_16_to_8() API for simple
-chopping.
-
-Prior to libpng-1.5.4, the png_set_user_limits() function could only be
-used to reduce the width and height limits from the value of
-PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
-that it could be used to override them.  Now this function will reduce or
-increase the limits.
-
-Starting in libpng-1.5.10, the user limits can be set en masse with the
-configuration option PNG_SAFE_LIMITS_SUPPORTED.  If this option is enabled,
-a set of "safe" limits is applied in pngpriv.h.  These can be overridden by
-application calls to png_set_user_limits(), png_set_user_chunk_cache_max(),
-and/or png_set_user_malloc_max() that increase or decrease the limits.  Also,
-in libpng-1.5.10 the default width and height limits were increased
-from 1,000,000 to 0x7ffffff (i.e., made unlimited).  Therefore, the
-limits are now
-                               default      safe
-   png_user_width_max        0x7fffffff    1,000,000
-   png_user_height_max       0x7fffffff    1,000,000
-   png_user_chunk_cache_max  0 (unlimited)   128
-   png_user_chunk_malloc_max 0 (unlimited) 8,000,000
-
-B. Changes to the build and configuration of libpng
-
-Details of internal changes to the library code can be found in the CHANGES
-file and in the GIT repository logs.  These will be of no concern to the vast
-majority of library users or builders, however the few who configure libpng
-to a non-default feature set may need to change how this is done.
-
-There should be no need for library builders to alter build scripts if
-these use the distributed build support - configure or the makefiles -
-however users of the makefiles may care to update their build scripts
-to build pnglibconf.h where the corresponding makefile does not do so.
-
-Building libpng with a non-default configuration has changed completely.
-The old method using pngusr.h should still work correctly even though the
-way pngusr.h is used in the build has been changed; however, library
-builders will probably want to examine the changes to take advantage of
-new capabilities and to simplify their build system.
-
-B.1 Specific changes to library configuration capabilities
-
-The library now supports a complete fixed point implementation and can
-thus be used on systems that have no floating point support or very
-limited or slow support.  Previously gamma correction, an essential part
-of complete PNG support, required reasonably fast floating point.
-
-As part of this the choice of internal implementation has been made
-independent of the choice of fixed versus floating point APIs and all the
-missing fixed point APIs have been implemented.
-
-The exact mechanism used to control attributes of API functions has
-changed.  A single set of operating system independent macro definitions
-is used and operating system specific directives are defined in
-pnglibconf.h
-
-As part of this the mechanism used to choose procedure call standards on
-those systems that allow a choice has been changed.  At present this only
-affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
-running on Intel processors.  As before, PNGAPI is defined where required
-to control the exported API functions; however, two new macros, PNGCBAPI
-and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
-(PNGCAPI) for functions that must match a C library prototype (currently
-only png_longjmp_ptr, which must match the C longjmp function.)  The new
-approach is documented in pngconf.h
-
-Despite these changes, libpng 1.5.0 only supports the native C function
-calling standard on those platforms tested so far (__cdecl on Microsoft
-Windows).  This is because the support requirements for alternative
-calling conventions seem to no longer exist.  Developers who find it
-necessary to set PNG_API_RULE to 1 should advise the mailing list
-(png-mng-implement) of this and library builders who use Openwatcom and
-therefore set PNG_API_RULE to 2 should also contact the mailing list.
-
-A new test program, pngvalid, is provided in addition to pngtest.
-pngvalid validates the arithmetic accuracy of the gamma correction
-calculations and includes a number of validations of the file format.
-A subset of the full range of tests is run when "make check" is done
-(in the 'configure' build.)  pngvalid also allows total allocated memory
-usage to be evaluated and performs additional memory overwrite validation.
-
-Many changes to individual feature macros have been made. The following
-are the changes most likely to be noticed by library builders who
-configure libpng:
-
-1) All feature macros now have consistent naming:
-
-#define PNG_NO_feature turns the feature off
-#define PNG_feature_SUPPORTED turns the feature on
-
-pnglibconf.h contains one line for each feature macro which is either:
-
-#define PNG_feature_SUPPORTED
-
-if the feature is supported or:
-
-/*#undef PNG_feature_SUPPORTED*/
-
-if it is not.  Library code consistently checks for the 'SUPPORTED' macro.
-It does not, and libpng applications should not, check for the 'NO' macro
-which will not normally be defined even if the feature is not supported.
-The 'NO' macros are only used internally for setting or not setting the
-corresponding 'SUPPORTED' macros.
-
-Compatibility with the old names is provided as follows:
-
-PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED
-
-And the following definitions disable the corresponding feature:
-
-PNG_SETJMP_NOT_SUPPORTED disables SETJMP
-PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS
-PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV
-PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS
-PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS
-PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS
-
-Library builders should remove use of the above, inconsistent, names.
-
-2) Warning and error message formatting was previously conditional on
-the STDIO feature. The library has been changed to use the
-CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled
-the library no longer uses the printf(3) functions, even though the
-default read/write implementations use (FILE) style stdio.h functions.
-
-3) Three feature macros now control the fixed/floating point decisions:
-
-PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs
-
-PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in
-practice these are normally required internally anyway (because the PNG
-file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT
-merely stops the function from being exported.
-
-PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating
-point implementation or the fixed point one.  Typically the fixed point
-implementation is larger and slower than the floating point implementation
-on a system that supports floating point, however it may be faster on a
-system which lacks floating point hardware and therefore uses a software
-emulation.
-
-4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the
-functions to read and write ints to be disabled independently of
-PNG_USE_READ_MACROS, which allows libpng to be built with the functions
-even though the default is to use the macros - this allows applications
-to choose at app buildtime whether or not to use macros (previously
-impossible because the functions weren't in the default build.)
-
-B.2 Changes to the configuration mechanism
-
-Prior to libpng-1.5.0 library builders who needed to configure libpng
-had either to modify the exported pngconf.h header file to add system
-specific configuration or had to write feature selection macros into
-pngusr.h and cause this to be included into pngconf.h by defining
-PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
-application built without PNG_USER_CONFIG defined would see the
-unmodified, default, libpng API and thus would probably fail to link.
-
-These mechanisms still work in the configure build and in any makefile
-build that builds pnglibconf.h, although the feature selection macros
-have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
-processed only once, when the exported header file pnglibconf.h is built.
-pngconf.h no longer includes pngusr.h, therefore pngusr.h is ignored after the
-build of pnglibconf.h and it is never included in an application build.
-
-The rarely used alternative of adding a list of feature macros to the
-CFLAGS setting in the build also still works, however the macros will be
-copied to pnglibconf.h and this may produce macro redefinition warnings
-when the individual C files are compiled.
-
-All configuration now only works if pnglibconf.h is built from
-scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
-(the original author of awk) maintains C source code of that awk and this
-and all known later implementations (often called by subtly different
-names - nawk and gawk for example) are adequate to build pnglibconf.h.
-The Sun Microsystems (now Oracle) program 'awk' is an earlier version
-and does not work; this may also apply to other systems that have a
-functioning awk called 'nawk'.
-
-Configuration options are now documented in scripts/pnglibconf.dfa.  This
-file also includes dependency information that ensures a configuration is
-consistent; that is, if a feature is switched off dependent features are
-also removed.  As a recommended alternative to using feature macros in
-pngusr.h a system builder may also define equivalent options in pngusr.dfa
-(or, indeed, any file) and add that to the configuration by setting
-DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
-how to do this, and a case where pngusr.h is still required.
-
-XI. Detecting libpng
-
-The png_get_io_ptr() function has been present since libpng-0.88, has never
-changed, and is unaffected by conditional compilation macros.  It is the
-best choice for use in configure scripts for detecting the presence of any
-libpng version since 0.88.  In an autoconf "configure.in" you could use
-
-    AC_CHECK_LIB(png, png_get_io_ptr, ...
-
-XII. Source code repository
-
-Since about February 2009, version 1.2.34, libpng has been under "git" source
-control.  The git repository was built from old libpng-x.y.z.tar.gz files
-going back to version 0.70.  You can access the git repository (read only)
-at
-
-    git://libpng.git.sourceforge.net/gitroot/libpng
-
-or you can browse it via "gitweb" at
-
-    http://libpng.git.sourceforge.net/git/gitweb.cgi?p=libpng
-
-Patches can be sent to glennrp at users.sourceforge.net or to
-png-mng-implement at lists.sourceforge.net or you can upload them to
-the libpng bug tracker at
-
-    http://libpng.sourceforge.net
-
-We also accept patches built from the tar or zip distributions, and
-simple verbal discriptions of bug fixes, reported either to the
-SourceForge bug tracker, to the png-mng-implement at lists.sf.net
-mailing list, or directly to glennrp.
-
-XIII. Coding style
-
-Our coding style is similar to the "Allman" style, with curly
-braces on separate lines:
-
-    if (condition)
-    {
-       action;
-    }
-
-    else if (another condition)
-    {
-       another action;
-    }
-
-The braces can be omitted from simple one-line actions:
-
-    if (condition)
-       return (0);
-
-We use 3-space indentation, except for continued statements which
-are usually indented the same as the first line of the statement
-plus four more spaces.
-
-For macro definitions we use 2-space indentation, always leaving the "#"
-in the first column.
-
-    #ifndef PNG_NO_FEATURE
-    #  ifndef PNG_FEATURE_SUPPORTED
-    #    define PNG_FEATURE_SUPPORTED
-    #  endif
-    #endif
-
-Comments appear with the leading "/*" at the same indentation as
-the statement that follows the comment:
-
-    /* Single-line comment */
-    statement;
-
-    /* This is a multiple-line
-     * comment.
-     */
-    statement;
-
-Very short comments can be placed after the end of the statement
-to which they pertain:
-
-    statement;    /* comment */
-
-We don't use C++ style ("//") comments. We have, however,
-used them in the past in some now-abandoned MMX assembler
-code.
-
-Functions and their curly braces are not indented, and
-exported functions are marked with PNGAPI:
-
- /* This is a public function that is visible to
-  * application programmers. It does thus-and-so.
-  */
- void PNGAPI
- png_exported_function(png_ptr, png_info, foo)
- {
-    body;
- }
-
-The prototypes for all exported functions appear in png.h,
-above the comment that says
-
-    /* Maintainer: Put new public prototypes here ... */
-
-We mark all non-exported functions with "/* PRIVATE */"":
-
- void /* PRIVATE */
- png_non_exported_function(png_ptr, png_info, foo)
- {
-    body;
- }
-
-The prototypes for non-exported functions (except for those in
-pngtest) appear in
-pngpriv.h
-above the comment that says
-
-  /* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
-
-To avoid polluting the global namespace, the names of all exported
-functions and variables begin with "png_", and all publicly visible C
-preprocessor macros begin with "PNG".  We request that applications that
-use libpng *not* begin any of their own symbols with either of these strings.
-
-We put a space after each comma and after each semicolon
-in "for" statements, and we put spaces before and after each
-C binary operator and after "for" or "while", and before
-"?".  We don't put a space between a typecast and the expression
-being cast, nor do we put one between a function name and the
-left parenthesis that follows it:
-
-    for (i = 2; i > 0; --i)
-       y[i] = a(x) + (int)b;
-
-We prefer #ifdef and #ifndef to #if defined() and if !defined()
-when there is only one macro being tested.
-
-We prefer to express integers that are used as bit masks in hex format,
-with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100).
-
-We do not use the TAB character for indentation in the C sources.
-
-Lines do not exceed 80 characters.
-
-Other rules can be inferred by inspecting the libpng source.
-
-XIV. Y2K Compliance in libpng
-
-March 29, 2012
-
-Since the PNG Development group is an ad-hoc body, we can't make
-an official declaration.
-
-This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.5.10 are Y2K compliant.  It is my belief that earlier
-versions were also Y2K compliant.
-
-Libpng only has three year fields.  One is a 2-byte unsigned integer that
-will hold years up to 65535.  The other two hold the date in text
-format, and will hold years up to 9999.
-
-The integer is
-    "png_uint_16 year" in png_time_struct.
-
-The strings are
-    "png_charp time_buffer" in png_struct and
-    "near_time_buffer", which is a local character string in png.c.
-
-There are seven time-related functions:
-
-    png_convert_to_rfc_1123() in png.c
-      (formerly png_convert_to_rfc_1152() in error)
-    png_convert_from_struct_tm() in pngwrite.c, called
-      in pngwrite.c
-    png_convert_from_time_t() in pngwrite.c
-    png_get_tIME() in pngget.c
-    png_handle_tIME() in pngrutil.c, called in pngread.c
-    png_set_tIME() in pngset.c
-    png_write_tIME() in pngwutil.c, called in pngwrite.c
-
-All appear to handle dates properly in a Y2K environment.  The
-png_convert_from_time_t() function calls gmtime() to convert from system
-clock time, which returns (year - 1900), which we properly convert to
-the full 4-digit year.  There is a possibility that applications using
-libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
-function, or that they are incorrectly passing only a 2-digit year
-instead of "year - 1900" into the png_convert_from_struct_tm() function,
-but this is not under our control.  The libpng documentation has always
-stated that it works with 4-digit years, and the APIs have been
-documented as such.
-
-The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
-integer to hold the year, and can hold years as large as 65535.
-
-zlib, upon which libpng depends, is also Y2K compliant.  It contains
-no date-related code.
-
-
-   Glenn Randers-Pehrson
-   libpng maintainer
-   PNG Development Group
diff --git a/extern/libpng/include/libpng.3 b/extern/libpng/include/libpng.3
deleted file mode 100644
index bba25afa78..0000000000
--- a/extern/libpng/include/libpng.3
+++ /dev/null
@@ -1,5982 +0,0 @@
-.TH LIBPNG 3 "March 29, 2012"
-.SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.5.10
-.SH SYNOPSIS
-\fI\fB
-
-\fB#include <png.h>\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_access_version_number \fI(void\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_build_grayscale_palette (int \fP\fIbit_depth\fP\fB, png_colorp \fIpalette\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_calloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_chunk_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_chunk_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_chunk_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_convert_from_struct_tm (png_timep \fP\fIptime\fP\fB, struct tm FAR * \fIttime\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_charp png_convert_to_rfc1123 (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fIptime\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_infop png_create_info_struct (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_structp png_create_read_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_structp png_create_read_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_structp png_create_write_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_structp png_create_write_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_data_freer (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIfreer\fP\fB, png_uint_32 \fImask)\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_destroy_read_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fP\fIinfo_ptr_ptr\fP\fB, png_infopp \fIend_info_ptr_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_destroy_write_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_err (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_free (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_free_default (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_bit_depth (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_bKGD (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fI*background\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_channels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_cHRM (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*white_x\fP\fB, double \fP\fI*white_y\fP\fB, double \fP\fI*red_x\fP\fB, double \fP\fI*red_y\fP\fB, double \fP\fI*green_x\fP\fB, double \fP\fI*green_y\fP\fB, double \fP\fI*blue_x\fP\fB, double \fI*blue_y\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_cHRM_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*white_x\fP\fB, png_uint_32 \fP\fI*white_y\fP\fB, png_uint_32 \fP\fI*red_x\fP\fB, png_uint_32 \fP\fI*red_y\fP\fB, png_uint_32 \fP\fI*green_x\fP\fB, png_uint_32 \fP\fI*green_y\fP\fB, png_uint_32 \fP\fI*blue_x\fP\fB, png_uint_32 \fI*blue_y\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_cHRM_XYZ (png_structp \fIpng_ptr,
-
-\fBpng_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*red_X\fP\fB, double \fP\fI*red_Y\fP\fB, double \fI*red_Z,
-
-\fBdouble \fP\fI*green_X\fP\fB, double \fP\fI*green_Y\fP\fB, double \fP\fI*green_Z\fP\fB, double \fI*blue_X,
-
-\fBdouble \fP\fI*blue_Y\fP\fB, double \fI*blue_Z\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fI*int_red_X\fP\fB, png_fixed_point \fP\fI*int_red_Y\fP\fB, png_fixed_point \fP\fI*int_red_Z\fP\fB, png_fixed_point \fP\fI*int_green_X\fP\fB, png_fixed_point \fP\fI*int_green_Y\fP\fB, png_fixed_point \fP\fI*int_green_Z\fP\fB, png_fixed_point \fP\fI*int_blue_X\fP\fB, png_fixed_point \fP\fI*int_blue_Y\fP\fB, png_fixed_point \fI*int_blue_Z\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_chunk_cache_max (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_alloc_size_t png_get_chunk_malloc_max (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_color_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_compression_buffer_size (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_compression_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_copyright (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_current_row_number \fI(png_const_structp\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_current_pass_number \fI(png_const_structp\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_get_error_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_filter_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_gAMA (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fI*file_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_gAMA_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fI*int_file_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_header_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_header_version (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_hIST (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fI*hist\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_iCCP (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_bytepp \fP\fIprofile\fP\fB, png_uint_32 \fI*proflen\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*width\fP\fB, png_uint_32 \fP\fI*height\fP\fB, int \fP\fI*bit_depth\fP\fB, int \fP\fI*color_type\fP\fB, int \fP\fI*interlace_type\fP\fB, int \fP\fI*compression_type\fP\fB, int \fI*filter_type\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_image_height (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_image_width (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_int_32 png_get_int_32 (png_bytep \fIbuf\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_interlace_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_const_bytep png_get_io_chunk_name (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_io_chunk_type (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_get_io_ptr (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_io_state (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_libpng_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_get_mem_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_oFFs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*offset_x\fP\fB, png_uint_32 \fP\fI*offset_y\fP\fB, int \fI*unit_type\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_pCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fI*purpose\fP\fB, png_int_32 \fP\fI*X0\fP\fB, png_int_32 \fP\fI*X1\fP\fB, int \fP\fI*type\fP\fB, int \fP\fI*nparams\fP\fB, png_charp \fP\fI*units\fP\fB, png_charpp \fI*params\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_pHYs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
-
-\fI\fB
-
-\fBfloat png_get_pixel_aspect_ratio (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_pHYs_dpi (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_fixed_point png_get_pixel_aspect_ratio_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_get_progressive_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_PLTE (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fI*palette\fP\fB, int \fI*num_palette\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_byte png_get_rgb_to_gray_status (png_const_structp \fIpng_ptr)
-
-\fBpng_uint_32 png_get_rowbytes (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_bytepp png_get_rows (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_sBIT (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fI*sig_bit\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_get_sCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, double* \fP\fIwidth\fP\fB, double* \fIheight\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_get_sCAL_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_fixed_pointp \fP\fIwidth\fP\fB, png_fixed_pointp \fIheight\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_get_sCAL_s (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_charpp \fP\fIwidth\fP\fB, png_charpp \fIheight\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_bytep png_get_signature (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_sPLT (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fI*splt_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_sRGB (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int \fI*file_srgb_intent\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_text (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fI*text_ptr\fP\fB, int \fI*num_text\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_tIME (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fI*mod_time\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_tRNS (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fI*trans_alpha\fP\fB, int \fP\fI*num_trans\fP\fB, png_color_16p \fI*trans_color\fP\fB);\fP
-
-\fI\fB
-
-\fB/* This function is really an inline macro. \fI*/
-
-\fBpng_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_uint_31 (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIbuf\fP\fB);\fP
-
-\fI\fB
-
-\fB/* This function is really an inline macro. \fI*/
-
-\fBpng_uint_32 png_get_uint_32 (png_bytep \fIbuf\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_unknown_chunks (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkpp \fIunknowns\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_get_user_chunk_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_user_height_max (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_get_user_transform_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_user_width_max (png_const_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_valid (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIflag\fP\fB);\fP
-
-\fI\fB
-
-\fBfloat png_get_x_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_fixed_point png_get_x_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_int_32 png_get_x_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_int_32 png_get_x_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_x_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_x_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBfloat png_get_y_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_fixed_point png_get_y_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_int_32 png_get_y_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_int_32 png_get_y_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_y_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_get_y_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, png_size_t \fIpng_info_struct_size\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_longjmp (png_structp \fP\fIpng_ptr\fP\fB, int \fIval\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_malloc_default (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_voidp png_malloc_warn (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_permit_mng_features (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fImng_features_permitted\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_process_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_size\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_size_t png_process_data_pause \fP\fI(png_structp\fP\fB, int \fIsave\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_process_data_skip \fI(png_structp\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_progressive_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIold_row\fP\fB, png_bytep \fInew_row\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_read_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_read_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_read_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_read_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fIdisplay_row\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_read_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_bytepp \fP\fIdisplay_row\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_read_update_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBint png_reset_zstream (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_alpha_mode (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, double \fIoutput_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_alpha_mode_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, png_fixed_point \fIoutput_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_background (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, double \fIbackground_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_background_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, png_uint_32 \fIbackground_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_benign_errors (png_structp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_bgr (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fIbackground\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_check_for_invalid_index(png_structrp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIwhite_x\fP\fB, double \fP\fIwhite_y\fP\fB, double \fP\fIred_x\fP\fB, double \fP\fIred_y\fP\fB, double \fP\fIgreen_x\fP\fB, double \fP\fIgreen_y\fP\fB, double \fP\fIblue_x\fP\fB, double \fIblue_y\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwhite_x\fP\fB, png_uint_32 \fP\fIwhite_y\fP\fB, png_uint_32 \fP\fIred_x\fP\fB, png_uint_32 \fP\fIred_y\fP\fB, png_uint_32 \fP\fIgreen_x\fP\fB, png_uint_32 \fP\fIgreen_y\fP\fB, png_uint_32 \fP\fIblue_x\fP\fB, png_uint_32 \fIblue_y\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_cHRM_XYZ (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIred_X\fP\fB, double \fP\fIred_Y\fP\fB, double \fP\fIred_Z\fP\fB, double \fP\fIgreen_X\fP\fB, double \fIgreen_Y,
-
-\fBdouble \fP\fIgreen_Z\fP\fB, double \fP\fIblue_X\fP\fB, double \fP\fIblue_Y\fP\fB, double \fIblue_Z\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fIint_red_X\fP\fB, png_fixed_point \fP\fIint_red_Y\fP\fB, png_fixed_point \fP\fIint_red_Z\fP\fB, png_fixed_point \fP\fIint_green_X\fP\fB, png_fixed_point \fP\fIint_green_Y\fP\fB, png_fixed_point \fP\fIint_green_Z\fP\fB, png_fixed_point \fP\fIint_blue_X\fP\fB, png_fixed_point \fP\fIint_blue_Y\fP\fB, png_fixed_point \fIint_blue_Z\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_chunk_cache_max (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIuser_chunk_cache_max\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_compression_method (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_crc_action (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcrit_action\fP\fB, int \fIancil_action\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_error_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarning_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_expand (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_expand_16 (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_expand_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_filler (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_filter (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImethod\fP\fB, int \fIfilters\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_filter_heuristics (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_doublep \fP\fIfilter_weights\fP\fB, png_doublep \fIfilter_costs\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_filter_heuristics_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_fixed_point_p \fP\fIfilter_weights\fP\fB, png_fixed_point_p \fIfilter_costs\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_flush (png_structp \fP\fIpng_ptr\fP\fB, int \fInrows\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_gamma (png_structp \fP\fIpng_ptr\fP\fB, double \fP\fIscreen_gamma\fP\fB, double \fIdefault_file_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_gamma_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIscreen_gamma\fP\fB, png_uint_32 \fIdefault_file_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fIfile_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIfile_gamma\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_gray_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fIhist\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_const_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_const_bytep \fP\fIprofile\fP\fB, png_uint_32 \fIproflen\fP\fB);\fP
-
-\fI\fB
-
-\fBint png_set_interlace_handling (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_invalid (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fImask\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_invert_alpha (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_invert_mono (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwidth\fP\fB, png_uint_32 \fP\fIheight\fP\fB, int \fP\fIbit_depth\fP\fB, int \fP\fIcolor_type\fP\fB, int \fP\fIinterlace_type\fP\fB, int \fP\fIcompression_type\fP\fB, int \fIfilter_type\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_keep_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIkeep\fP\fB, png_bytep \fP\fIchunk_list\fP\fB, int \fInum_chunks\fP\fB);\fP
-
-\fI\fB
-
-\fBjmp_buf* png_set_longjmp_fn (png_structp \fP\fIpng_ptr\fP\fB, png_longjmp_ptr \fP\fIlongjmp_fn\fP\fB, size_t \fIjmp_buf_size\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_chunk_malloc_max (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIuser_chunk_cache_max\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_compression_buffer_size (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_mem_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIoffset_x\fP\fB, png_uint_32 \fP\fIoffset_y\fP\fB, int \fIunit_type\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_packing (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_packswap (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_palette_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIpurpose\fP\fB, png_int_32 \fP\fIX0\fP\fB, png_int_32 \fP\fIX1\fP\fB, int \fP\fItype\fP\fB, int \fP\fInparams\fP\fB, png_charp \fP\fIunits\fP\fB, png_charpp \fIparams\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIres_x\fP\fB, png_uint_32 \fP\fIres_y\fP\fB, int \fIunit_type\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_progressive_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIprogressive_ptr\fP\fB, png_progressive_info_ptr \fP\fIinfo_fn\fP\fB, png_progressive_row_ptr \fP\fIrow_fn\fP\fB, png_progressive_end_ptr \fIend_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fInum_palette\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_quantize (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fP\fInum_palette\fP\fB, int \fP\fImaximum_colors\fP\fB, png_uint_16p \fP\fIhistogram\fP\fB, int \fIfull_quantize\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fIread_data_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_read_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_read_status_ptr \fIread_row_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_read_user_chunk_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_chunk_ptr\fP\fB, png_user_chunk_ptr \fIread_user_chunk_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_read_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIread_user_transform_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_rgb_to_gray (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIerror_action\fP\fB, double \fP\fIred\fP\fB, double \fIgreen\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_rgb_to_gray_fixed (png_structp \fP\fIpng_ptr\fP\fB, int error_action png_uint_32 \fP\fIred\fP\fB, png_uint_32 \fIgreen\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_rows (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytepp \fIrow_pointers\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fIsig_bit\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, double \fP\fIwidth\fP\fB, double \fIheight\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_sCAL_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_fixed_point \fP\fIwidth\fP\fB, png_fixed_point \fIheight\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_sCAL_s (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_charp \fP\fIwidth\fP\fB, png_charp \fIheight\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_scale_16 (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_shift (png_structp \fP\fIpng_ptr\fP\fB, png_color_8p \fItrue_bits\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_sig_bytes (png_structp \fP\fIpng_ptr\fP\fB, int \fInum_bytes\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fP\fIsplt_ptr\fP\fB, int \fInum_spalettes\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_sRGB_gAMA_and_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_strip_16 (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_strip_alpha (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_strip_error_numbers (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIstrip_mode\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_swap (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_swap_alpha (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_text (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fItext_ptr\fP\fB, int \fInum_text\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_text_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_text_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_text_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_text_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid \fP\fIpng_set_text_compression_method\fP\fB, (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod)\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fItrans_alpha\fP\fB, int \fP\fInum_trans\fP\fB, png_color_16p \fItrans_color\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_tRNS_to_alpha (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBpng_uint_32 png_set_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkp \fP\fIunknowns\fP\fB, int \fP\fInum\fP\fB, int \fIlocation\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_unknown_chunk_location (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIchunk\fP\fB, int \fIlocation\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_user_limits (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIuser_width_max\fP\fB, png_uint_32 \fIuser_height_max\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_user_transform_info (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_transform_ptr\fP\fB, int \fP\fIuser_transform_depth\fP\fB, int \fIuser_transform_channels\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_write_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fP\fIwrite_data_fn\fP\fB, png_flush_ptr \fIoutput_flush_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_write_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_write_status_ptr \fIwrite_row_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_set_write_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIwrite_user_transform_fn\fP\fB);\fP
-
-\fI\fB
-
-\fBint png_sig_cmp (png_bytep \fP\fIsig\fP\fB, png_size_t \fP\fIstart\fP\fB, png_size_t \fInum_to_check\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_start_read_image (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_chunk_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_chunk_end (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_chunk_start (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_flush (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_info_before_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_write_sig (png_structp \fIpng_ptr\fP\fB);\fP
-
-\fI\fB
-
-\fBvoidpf png_zalloc (voidpf \fP\fIpng_ptr\fP\fB, uInt \fP\fIitems\fP\fB, uInt \fIsize\fP\fB);\fP
-
-\fI\fB
-
-\fBvoid png_zfree (voidpf \fP\fIpng_ptr\fP\fB, voidpf \fIptr\fP\fB);\fP
-
-\fI\fB
-
-.SH DESCRIPTION
-The
-.I libpng
-library supports encoding, decoding, and various manipulations of
-the Portable Network Graphics (PNG) format image files.  It uses the
-.IR zlib(3)
-compression library.
-Following is a copy of the libpng-manual.txt file that accompanies libpng.
-.SH LIBPNG.TXT
-libpng-manual.txt - A description on how to use and modify libpng
-
- libpng version 1.5.10 - March 29, 2012
- Updated and distributed by Glenn Randers-Pehrson
- <glennrp at users.sourceforge.net>
- Copyright (c) 1998-2011 Glenn Randers-Pehrson
-
- This document is released under the libpng license.
- For conditions of distribution and use, see the disclaimer
- and license in png.h
-
- Based on:
-
- libpng versions 0.97, January 1998, through 1.5.10 - March 29, 2012
- Updated and distributed by Glenn Randers-Pehrson
- Copyright (c) 1998-2011 Glenn Randers-Pehrson
-
- libpng 1.0 beta 6  version 0.96 May 28, 1997
- Updated and distributed by Andreas Dilger
- Copyright (c) 1996, 1997 Andreas Dilger
-
- libpng 1.0 beta 2 - version 0.88  January 26, 1996
- For conditions of distribution and use, see copyright
- notice in png.h. Copyright (c) 1995, 1996 Guy Eric
- Schalnat, Group 42, Inc.
-
- Updated/rewritten per request in the libpng FAQ
- Copyright (c) 1995, 1996 Frank J. T. Wojcik
- December 18, 1995 & January 20, 1996
-
-.SH I. Introduction
-
-This file describes how to use and modify the PNG reference library
-(known as libpng) for your own use.  There are five sections to this
-file: introduction, structures, reading, writing, and modification and
-configuration notes for various special platforms.  In addition to this
-file, example.c is a good starting point for using the library, as
-it is heavily commented and should include everything most people
-will need.  We assume that libpng is already installed; see the
-INSTALL file for instructions on how to install libpng.
-
-For examples of libpng usage, see the files "example.c", "pngtest.c",
-and the files in the "contrib" directory, all of which are included in
-the libpng distribution.
-
-Libpng was written as a companion to the PNG specification, as a way
-of reducing the amount of time and effort it takes to support the PNG
-file format in application programs.
-
-The PNG specification (second edition), November 2003, is available as
-a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2003 (E)) at
-<http://www.w3.org/TR/2003/REC-PNG-20031110/
-The W3C and ISO documents have identical technical content.
-
-The PNG-1.2 specification is available at
-<http://www.libpng.org/pub/png/documents/>.  It is technically equivalent
-to the PNG specification (second edition) but has some additional material.
-
-The PNG-1.0 specification is available
-as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a
-W3C Recommendation <http://www.w3.org/TR/REC.png.html>.
-
-Some additional chunks are described in the special-purpose public chunks
-documents at <http://www.libpng.org/pub/png/documents/>.
-
-Other information
-about PNG, and the latest version of libpng, can be found at the PNG home
-page, <http://www.libpng.org/pub/png/>.
-
-Most users will not have to modify the library significantly; advanced
-users may want to modify it more.  All attempts were made to make it as
-complete as possible, while keeping the code easy to understand.
-Currently, this library only supports C.  Support for other languages
-is being considered.
-
-Libpng has been designed to handle multiple sessions at one time,
-to be easily modifiable, to be portable to the vast majority of
-machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
-to use.  The ultimate goal of libpng is to promote the acceptance of
-the PNG file format in whatever way possible.  While there is still
-work to be done (see the TODO file), libpng should cover the
-majority of the needs of its users.
-
-Libpng uses zlib for its compression and decompression of PNG files.
-Further information about zlib, and the latest version of zlib, can
-be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>.
-The zlib compression utility is a general purpose utility that is
-useful for more than PNG files, and can be used without libpng.
-See the documentation delivered with zlib for more details.
-You can usually find the source files for the zlib utility wherever you
-find the libpng source files.
-
-Libpng is thread safe, provided the threads are using different
-instances of the structures.  Each thread should have its own
-png_struct and png_info instances, and thus its own image.
-Libpng does not protect itself against two threads using the
-same instance of a structure.
-
-.SH II. Structures
-
-There are two main structures that are important to libpng, png_struct
-and png_info.  Both are internal structures that are no longer exposed
-in the libpng interface (as of libpng 1.5.0).
-
-The png_info structure is designed to provide information about the
-PNG file.  At one time, the fields of png_info were intended to be
-directly accessible to the user.  However, this tended to cause problems
-with applications using dynamically loaded libraries, and as a result
-a set of interface functions for png_info (the png_get_*() and png_set_*()
-functions) was developed, and direct access to the png_info fields was
-deprecated..
-
-The png_struct structure is the object used by the library to decode a
-single image.  As of 1.5.0 this structure is also not exposed.
-
-Almost all libpng APIs require a pointer to a png_struct as the first argument.
-Many (in particular the png_set and png_get APIs) also require a pointer
-to png_info as the second argument.  Some application visible macros
-defined in png.h designed for basic data access (reading and writing
-integers in the PNG format) don't take a png_info pointer, but it's almost
-always safe to assume that a (png_struct*) has to be passed to call an API
-function.
-
-You can have more than one png_info structure associated with an image,
-as illustrated in pngtest.c, one for information valid prior to the
-IDAT chunks and another (called "end_info" below) for things after them.
-
-The png.h header file is an invaluable reference for programming with libpng.
-And while I'm on the topic, make sure you include the libpng header file:
-
-#include <png.h>
-
-and also (as of libpng-1.5.0) the zlib header file, if you need it:
-
-#include <zlib.h>
-
-.SS Types
-
-The png.h header file defines a number of integral types used by the
-APIs.  Most of these are fairly obvious; for example types corresponding
-to integers of particular sizes and types for passing color values.
-
-One exception is how non-integral numbers are handled.  For application
-convenience most APIs that take such numbers have C (double) arguments,
-however internally PNG, and libpng, use 32 bit signed integers and encode
-the value by multiplying by 100,000.  As of libpng 1.5.0 a convenience
-macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
-which is simply (png_int_32).
-
-All APIs that take (double) arguments also have a matching API that
-takes the corresponding fixed point integer arguments.  The fixed point
-API has the same name as the floating point one with "_fixed" appended.
-The actual range of values permitted in the APIs is frequently less than
-the full range of (png_fixed_point) (-21474 to +21474).  When APIs require
-a non-negative argument the type is recorded as png_uint_32 above.  Consult
-the header file and the text below for more information.
-
-Special care must be take with sCAL chunk handling because the chunk itself
-uses non-integral values encoded as strings containing decimal floating point
-numbers.  See the comments in the header file.
-
-.SS Configuration
-
-The main header file function declarations are frequently protected by C
-preprocessing directives of the form:
-
-    #ifdef PNG_feature_SUPPORTED
-    declare-function
-    #endif
-    ...
-    #ifdef PNG_feature_SUPPORTED
-    use-function
-    #endif
-
-The library can be built without support for these APIs, although a
-standard build will have all implemented APIs.  Application programs
-should check the feature macros before using an API for maximum
-portability.  From libpng 1.5.0 the feature macros set during the build
-of libpng are recorded in the header file "pnglibconf.h" and this file
-is always included by png.h.
-
-If you don't need to change the library configuration from the default, skip to
-the next section ("Reading").
-
-Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
-of the build project files in the 'projects' directory simply copy
-scripts/pnglibconf.h.prebuilt to pnglibconf.h.  This means that these build
-systems do not permit easy auto-configuration of the library - they only
-support the default configuration.
-
-The easiest way to make minor changes to the libpng configuration when
-auto-configuration is supported is to add definitions to the command line
-using (typically) CPPFLAGS.  For example:
-
-CPPFLAGS=-DPNG_NO_FLOATING_ARITHMETIC
-
-will change the internal libpng math implementation for gamma correction and
-other arithmetic calculations to fixed point, avoiding the need for fast
-floating point support.  The result can be seen in the generated pnglibconf.h -
-make sure it contains the changed feature macro setting.
-
-If you need to make more extensive configuration changes - more than one or two
-feature macro settings - you can either add -DPNG_USER_CONFIG to the build
-command line and put a list of feature macro settings in pngusr.h or you can set
-DFA_XTRA (a makefile variable) to a file containing the same information in the
-form of 'option' settings.
-
-A. Changing pnglibconf.h
-
-A variety of methods exist to build libpng.  Not all of these support
-reconfiguration of pnglibconf.h.  To reconfigure pnglibconf.h it must either be
-rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
-
-Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to
-pnglibconf.h and changing the lines defining the supported features, paying
-very close attention to the 'option' information in scripts/pnglibconf.dfa
-that describes those features and their requirements.  This is easy to get
-wrong.
-
-B. Configuration using DFA_XTRA
-
-Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
-variant such as 'nawk' or 'gawk', is available.  The configure build will
-automatically find an appropriate awk and build pnglibconf.h.
-The scripts/pnglibconf.mak file contains a set of make rules for doing the
-same thing if configure is not used, and many of the makefiles in the scripts
-directory use this approach.
-
-When rebuilding simply write a new file containing changed options and set
-DFA_XTRA to the name of this file.  This causes the build to append the new file
-to the end of scripts/pnglibconf.dfa.  The pngusr.dfa file should contain lines
-of the following forms:
-
-everything = off
-
-This turns all optional features off.  Include it at the start of pngusr.dfa to
-make it easier to build a minimal configuration.  You will need to turn at least
-some features on afterward to enable either reading or writing code, or both.
-
-option feature on
-option feature off
-
-Enable or disable a single feature.  This will automatically enable other
-features required by a feature that is turned on or disable other features that
-require a feature which is turned off.  Conflicting settings will cause an error
-message to be emitted by awk.
-
-setting feature default value
-
-Changes the default value of setting 'feature' to 'value'.  There are a small
-number of settings listed at the top of pnglibconf.h, they are documented in the
-source code.  Most of these values have performance implications for the library
-but most of them have no visible effect on the API.  Some can also be overridden
-from the API.
-
-This method of building a customized pnglibconf.h is illustrated in
-contrib/pngminim/*.  See the "$(PNGCONF):" target in the makefile and
-pngusr.dfa in these directories.
-
-C. Configuration using PNG_USR_CONFIG
-
-If -DPNG_USR_CONFIG is added to the CFLAGS when pnglibconf.h is built the file
-pngusr.h will automatically be included before the options in
-scripts/pnglibconf.dfa are processed.  Your pngusr.h file should contain only
-macro definitions turning features on or off or setting settings.
-
-Apart from the global setting "everything = off" all the options listed above
-can be set using macros in pngusr.h:
-
-#define PNG_feature_SUPPORTED
-
-is equivalent to:
-
-option feature on
-
-#define PNG_NO_feature
-
-is equivalent to:
-
-option feature off
-
-#define PNG_feature value
-
-is equivalent to:
-
-setting feature default value
-
-Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
-pngusr file you supply override the contents of scripts/pnglibconf.dfa
-
-If confusing or incomprehensible behavior results it is possible to
-examine the intermediate file pnglibconf.dfn to find the full set of
-dependency information for each setting and option.  Simply locate the
-feature in the file and read the C comments that precede it.
-
-This method is also illustrated in the contrib/pngminim/* makefiles and
-pngusr.h.
-
-.SH III. Reading
-
-We'll now walk you through the possible functions to call when reading
-in a PNG file sequentially, briefly explaining the syntax and purpose
-of each one.  See example.c and png.h for more detail.  While
-progressive reading is covered in the next section, you will still
-need some of the functions discussed in this section to read a PNG
-file.
-
-.SS Setup
-
-You will want to do the I/O initialization(*) before you get into libpng,
-so if it doesn't work, you don't have much to undo.  Of course, you
-will also want to insure that you are, in fact, dealing with a PNG
-file.  Libpng provides a simple check to see if a file is a PNG file.
-To use it, pass in the first 1 to 8 bytes of the file to the function
-png_sig_cmp(), and it will return 0 (false) if the bytes match the
-corresponding bytes of the PNG signature, or nonzero (true) otherwise.
-Of course, the more bytes you pass in, the greater the accuracy of the
-prediction.
-
-If you are intending to keep the file pointer open for use in libpng,
-you must ensure you don't read more than 8 bytes from the beginning
-of the file, and you also have to make a call to png_set_sig_bytes_read()
-with the number of bytes you read from the beginning.  Libpng will
-then only check the bytes (if any) that your program didn't read.
-
-(*): If you are not using the standard I/O functions, you will need
-to replace them with custom functions.  See the discussion under
-Customizing libpng.
-
-
-    FILE *fp = fopen(file_name, "rb");
-    if (!fp)
-    {
-       return (ERROR);
-    }
-
-    fread(header, 1, number, fp);
-    is_png = !png_sig_cmp(header, 0, number);
-
-    if (!is_png)
-    {
-       return (NOT_PNG);
-    }
-
-
-Next, png_struct and png_info need to be allocated and initialized.  In
-order to ensure that the size of these structures is correct even with a
-dynamically linked libpng, there are functions to initialize and
-allocate the structures.  We also pass the library version, optional
-pointers to error handling functions, and a pointer to a data struct for
-use by the error functions, if necessary (the pointer and functions can
-be NULL if the default error handlers are to be used).  See the section
-on Changes to Libpng below regarding the old initialization functions.
-The structure allocation functions quietly return NULL if they fail to
-create the structure, so your application should check for that.
-
-    png_structp png_ptr = png_create_read_struct
-        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-        user_error_fn, user_warning_fn);
-
-    if (!png_ptr)
-       return (ERROR);
-
-    png_infop info_ptr = png_create_info_struct(png_ptr);
-
-    if (!info_ptr)
-    {
-       png_destroy_read_struct(&png_ptr,
-           (png_infopp)NULL, (png_infopp)NULL);
-       return (ERROR);
-    }
-
-If you want to use your own memory allocation routines,
-use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
-png_create_read_struct_2() instead of png_create_read_struct():
-
-    png_structp png_ptr = png_create_read_struct_2
-        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-        user_error_fn, user_warning_fn, (png_voidp)
-        user_mem_ptr, user_malloc_fn, user_free_fn);
-
-The error handling routines passed to png_create_read_struct()
-and the memory alloc/free routines passed to png_create_struct_2()
-are only necessary if you are not using the libpng supplied error
-handling and memory alloc/free functions.
-
-When libpng encounters an error, it expects to longjmp back
-to your routine.  Therefore, you will need to call setjmp and pass
-your png_jmpbuf(png_ptr).  If you read the file from different
-routines, you will need to update the longjmp buffer every time you enter
-a new routine that will call a png_*() function.
-
-See your documentation of setjmp/longjmp for your compiler for more
-information on setjmp/longjmp.  See the discussion on libpng error
-handling in the Customizing Libpng section below for more information
-on the libpng error handling.  If an error occurs, and libpng longjmp's
-back to your setjmp, you will want to call png_destroy_read_struct() to
-free any memory.
-
-    if (setjmp(png_jmpbuf(png_ptr)))
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-           &end_info);
-       fclose(fp);
-       return (ERROR);
-    }
-
-Pass (png_infopp)NULL instead of &end_info if you didn't create
-an end_info structure.
-
-If you would rather avoid the complexity of setjmp/longjmp issues,
-you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT() which defaults to abort().
-
-You can #define PNG_ABORT() to a function that does something
-more useful than abort(), as long as your function does not
-return.
-
-Now you need to set up the input code.  The default for libpng is to
-use the C function fread().  If you use this, you will need to pass a
-valid FILE * in the function png_init_io().  Be sure that the file is
-opened in binary mode.  If you wish to handle reading data in another
-way, you need not call the png_init_io() function, but you must then
-implement the libpng I/O methods discussed in the Customizing Libpng
-section below.
-
-    png_init_io(png_ptr, fp);
-
-If you had previously opened the file and read any of the signature from
-the beginning in order to see if this was a PNG file, you need to let
-libpng know that there are some bytes missing from the start of the file.
-
-    png_set_sig_bytes(png_ptr, number);
-
-You can change the zlib compression buffer size to be used while
-reading compressed data with
-
-    png_set_compression_buffer_size(png_ptr, buffer_size);
-
-where the default size is 8192 bytes.  Note that the buffer size
-is changed immediately and the buffer is reallocated immediately,
-instead of setting a flag to be acted upon later.
-
-If you want CRC errors to be handled in a different manner than
-the default, use
-
-    png_set_crc_action(png_ptr, crit_action, ancil_action);
-
-The values for png_set_crc_action() say how libpng is to handle CRC errors in
-ancillary and critical chunks, and whether to use the data contained
-therein.  Note that it is impossible to "discard" data in a critical
-chunk.
-
-Choices for (int) crit_action are
-   PNG_CRC_DEFAULT      0  error/quit
-   PNG_CRC_ERROR_QUIT   1  error/quit
-   PNG_CRC_WARN_USE     3  warn/use data
-   PNG_CRC_QUIET_USE    4  quiet/use data
-   PNG_CRC_NO_CHANGE    5  use the current value
-
-Choices for (int) ancil_action are
-   PNG_CRC_DEFAULT      0  error/quit
-   PNG_CRC_ERROR_QUIT   1  error/quit
-   PNG_CRC_WARN_DISCARD 2  warn/discard data
-   PNG_CRC_WARN_USE     3  warn/use data
-   PNG_CRC_QUIET_USE    4  quiet/use data
-   PNG_CRC_NO_CHANGE    5  use the current value
-
-.SS Setting up callback code
-
-You can set up a callback function to handle any unknown chunks in the
-input stream. You must supply the function
-
-    read_chunk_callback(png_structp png_ptr,
-         png_unknown_chunkp chunk);
-    {
-       /* The unknown chunk structure contains your
-          chunk data, along with similar data for any other
-          unknown chunks: */
-
-           png_byte name[5];
-           png_byte *data;
-           png_size_t size;
-
-       /* Note that libpng has already taken care of
-          the CRC handling */
-
-       /* put your code here.  Search for your chunk in the
-          unknown chunk structure, process it, and return one
-          of the following: */
-
-       return (-n); /* chunk had an error */
-       return (0); /* did not recognize */
-       return (n); /* success */
-    }
-
-(You can give your function another name that you like instead of
-"read_chunk_callback")
-
-To inform libpng about your function, use
-
-    png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
-        read_chunk_callback);
-
-This names not only the callback function, but also a user pointer that
-you can retrieve with
-
-    png_get_user_chunk_ptr(png_ptr);
-
-If you call the png_set_read_user_chunk_fn() function, then all unknown
-chunks will be saved when read, in case your callback function will need
-one or more of them.  This behavior can be changed with the
-png_set_keep_unknown_chunks() function, described below.
-
-At this point, you can set up a callback function that will be
-called after each row has been read, which you can use to control
-a progress meter or the like.  It's demonstrated in pngtest.c.
-You must supply a function
-
-    void read_row_callback(png_structp png_ptr,
-       png_uint_32 row, int pass);
-    {
-      /* put your code here */
-    }
-
-(You can give it another name that you like instead of "read_row_callback")
-
-To inform libpng about your function, use
-
-    png_set_read_status_fn(png_ptr, read_row_callback);
-
-When this function is called the row has already been completely processed and
-the 'row' and 'pass' refer to the next row to be handled.  For the
-non-interlaced case the row that was just handled is simply one less than the
-passed in row number, and pass will always be 0.  For the interlaced case the
-same applies unless the row value is 0, in which case the row just handled was
-the last one from one of the preceding passes.  Because interlacing may skip a
-pass you cannot be sure that the preceding pass is just 'pass-1', if you really
-need to know what the last pass is record (row,pass) from the callback and use
-the last recorded value each time.
-
-As with the user transform you can find the output row using the
-PNG_ROW_FROM_PASS_ROW macro.
-
-.SS Unknown-chunk handling
-
-Now you get to set the way the library processes unknown chunks in the
-input PNG stream. Both known and unknown chunks will be read.  Normal
-behavior is that known chunks will be parsed into information in
-various info_ptr members while unknown chunks will be discarded. This
-behavior can be wasteful if your application will never use some known
-chunk types. To change this, you can call:
-
-    png_set_keep_unknown_chunks(png_ptr, keep,
-        chunk_list, num_chunks);
-    keep       - 0: default unknown chunk handling
-                 1: ignore; do not keep
-                 2: keep only if safe-to-copy
-                 3: keep even if unsafe-to-copy
-
-               You can use these definitions:
-                 PNG_HANDLE_CHUNK_AS_DEFAULT   0
-                 PNG_HANDLE_CHUNK_NEVER        1
-                 PNG_HANDLE_CHUNK_IF_SAFE      2
-                 PNG_HANDLE_CHUNK_ALWAYS       3
-
-    chunk_list - list of chunks affected (a byte string,
-                 five bytes per chunk, NULL or '\0' if
-                 num_chunks is 0)
-
-    num_chunks - number of chunks affected; if 0, all
-                 unknown chunks are affected.  If nonzero,
-                 only the chunks in the list are affected
-
-Unknown chunks declared in this way will be saved as raw data onto a
-list of png_unknown_chunk structures.  If a chunk that is normally
-known to libpng is named in the list, it will be handled as unknown,
-according to the "keep" directive.  If a chunk is named in successive
-instances of png_set_keep_unknown_chunks(), the final instance will
-take precedence.  The IHDR and IEND chunks should not be named in
-chunk_list; if they are, libpng will process them normally anyway.
-If you know that your application will never make use of some particular
-chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below.
-
-Here is an example of the usage of png_set_keep_unknown_chunks(),
-where the private "vpAg" chunk will later be processed by a user chunk
-callback function:
-
-    png_byte vpAg[5]={118, 112,  65, 103, (png_byte) '\0'};
-
-    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-      png_byte unused_chunks[]=
-      {
-        104,  73,  83,  84, (png_byte) '\0',   /* hIST */
-        105,  84,  88, 116, (png_byte) '\0',   /* iTXt */
-        112,  67,  65,  76, (png_byte) '\0',   /* pCAL */
-        115,  67,  65,  76, (png_byte) '\0',   /* sCAL */
-        115,  80,  76,  84, (png_byte) '\0',   /* sPLT */
-        116,  73,  77,  69, (png_byte) '\0',   /* tIME */
-      };
-    #endif
-
-    ...
-
-    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-      /* ignore all unknown chunks: */
-      png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
-
-      /* except for vpAg: */
-      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
-
-      /* also ignore unused known chunks: */
-      png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
-         (int)sizeof(unused_chunks)/5);
-    #endif
-
-.SS User limits
-
-The PNG specification allows the width and height of an image to be as
-large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
-Since very few applications really need to process such large images,
-we have imposed an arbitrary 1-million limit on rows and columns.
-Larger images will be rejected immediately with a png_error() call. If
-you wish to change this limit, you can use
-
-   png_set_user_limits(png_ptr, width_max, height_max);
-
-to set your own limits, or use width_max = height_max = 0x7fffffffL
-to allow all valid dimensions (libpng may reject some very large images
-anyway because of potential buffer overflow conditions).
-
-You should put this statement after you create the PNG structure and
-before calling png_read_info(), png_read_png(), or png_process_data().
-
-When writing a PNG datastream, put this statement before calling
-png_write_info() or png_write_png().
-
-If you need to retrieve the limits that are being applied, use
-
-   width_max = png_get_user_width_max(png_ptr);
-   height_max = png_get_user_height_max(png_ptr);
-
-The PNG specification sets no limit on the number of ancillary chunks
-allowed in a PNG datastream.  You can impose a limit on the total number
-of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with
-
-   png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
-
-where 0x7fffffffL means unlimited.  You can retrieve this limit with
-
-   chunk_cache_max = png_get_chunk_cache_max(png_ptr);
-
-This limit also applies to the number of buffers that can be allocated
-by png_decompress_chunk() while decompressing iTXt, zTXt, and iCCP chunks.
-
-You can also set a limit on the amount of memory that a compressed chunk
-other than IDAT can occupy, with
-
-   png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
-
-and you can retrieve the limit with
-
-   chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
-
-Any chunks that would cause either of these limits to be exceeded will
-be ignored.
-
-.SS Information about your system
-
-If you intend to display the PNG or to incorporate it in other image data you
-need to tell libpng information about your display or drawing surface so that
-libpng can convert the values in the image to match the display.
-
-From libpng-1.5.4 this information can be set before reading the PNG file
-header.  In earlier versions png_set_gamma() existed but behaved incorrectly if
-called before the PNG file header had been read and png_set_alpha_mode() did not
-exist.
-
-If you need to support versions prior to libpng-1.5.4 test the version number
-as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures
-described in the appropriate manual page.
-
-You give libpng the encoding expected by your system expressed as a 'gamma'
-value.  You can also specify a default encoding for the PNG file in
-case the required information is missing from the file.  By default libpng
-assumes that the PNG data matches your system, to keep this default call:
-
-   png_set_gamma(png_ptr, screen_gamma, 1/screen_gamma/*file gamma*/);
-
-or you can use the fixed point equivalent:
-
-   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma, PNG_FP_1/screen_gamma);
-
-If you don't know the gamma for your system it is probably 2.2 - a good
-approximation to the IEC standard for display systems (sRGB).  If images are
-too contrasty or washed out you got the value wrong - check your system
-documentation!
-
-Many systems permit the system gamma to be changed via a lookup table in the
-display driver, a few systems, including older Macs, change the response by
-default.  As of 1.5.4 three special values are available to handle common
-situations:
-
-   PNG_DEFAULT_sRGB: Indicates that the system conforms to the IEC 61966-2-1
-                     standard.  This matches almost all systems.
-   PNG_GAMMA_MAC_18: Indicates that the system is an older (pre Mac OS 10.6)
-                     Apple Macintosh system with the default settings.
-   PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates that the
-                     system expects data with no gamma encoding.
-
-You would use the linear (unencoded) value if you need to process the pixel
-values further because this avoids the need to decode and reencode each
-component value whenever arithmetic is performed.  A lot of graphics software
-uses linear values for this reason, often with higher precision component values
-to preserve overall accuracy.
-
-The second thing you may need to tell libpng about is how your system handles
-alpha channel information.  Some, but not all, PNG files contain an alpha
-channel.  To display these files correctly you need to compose the data onto a
-suitable background, as described in the PNG specification.
-
-Libpng only supports composing onto a single color (using png_set_background;
-see below).  Otherwise you must do the composition yourself and, in this case,
-you may need to call png_set_alpha_mode:
-
-#if PNG_LIBPNG_VER >= 10504
-   png_set_alpha_mode(png_ptr, mode, screen_gamma);
-#else
-   png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma);
-#endif
-
-The screen_gamma value is the same as the argument to png_set_gamma; however,
-how it affects the output depends on the mode.  png_set_alpha_mode() sets the
-file gamma default to 1/screen_gamma, so normally you don't need to call
-png_set_gamma.  If you need different defaults call png_set_gamma() before
-png_set_alpha_mode() - if you call it after it will override the settings made
-by png_set_alpha_mode().
-
-The mode is as follows:
-
-    PNG_ALPHA_PNG: The data is encoded according to the PNG specification.  Red,
-green and blue, or gray, components are gamma encoded color
-values and are not premultiplied by the alpha value.  The
-alpha value is a linear measure of the contribution of the
-pixel to the corresponding final output pixel.
-
-You should normally use this format if you intend to perform
-color correction on the color values; most, maybe all, color
-correction software has no handling for the alpha channel and,
-anyway, the math to handle pre-multiplied component values is
-unnecessarily complex.
-
-Before you do any arithmetic on the component values you need
-to remove the gamma encoding and multiply out the alpha
-channel.  See the PNG specification for more detail.  It is
-important to note that when an image with an alpha channel is
-scaled, linear encoded, pre-multiplied component values must
-be used!
-
-The remaining modes assume you don't need to do any further color correction or
-that if you do, your color correction software knows all about alpha (it
-probably doesn't!)
-
-    PNG_ALPHA_STANDARD:  The data libpng produces
-is encoded in the standard way
-assumed by most correctly written graphics software.
-The gamma encoding will be removed by libpng and the
-linear component values will be pre-multiplied by the
-alpha channel.
-
-With this format the final image must be re-encoded to
-match the display gamma before the image is displayed.
-If your system doesn't do that, yet still seems to
-perform arithmetic on the pixels without decoding them,
-it is broken - check out the modes below.
-
-With PNG_ALPHA_STANDARD libpng always produces linear
-component values, whatever screen_gamma you supply.  The
-screen_gamma value is, however, used as a default for
-the file gamma if the PNG file has no gamma information.
-
-If you call png_set_gamma() after png_set_alpha_mode() you
-will override the linear encoding.  Instead the
-pre-multiplied pixel values will be gamma encoded but
-the alpha channel will still be linear.  This may
-actually match the requirements of some broken software,
-but it is unlikely.
-
-While linear 8-bit data is often used it has
-insufficient precision for any image with a reasonable
-dynamic range.  To avoid problems, and if your software
-supports it, use png_set_expand_16() to force all
-components to 16 bits.
-
-    PNG_ALPHA_OPTIMIZED: This mode is the same
-as PNG_ALPHA_STANDARD except that
-completely opaque pixels are gamma encoded according to
-the screen_gamma value.  Pixels with alpha less than 1.0
-will still have linear components.
-
-Use this format if you have control over your
-compositing software and do don't do other arithmetic
-(such as scaling) on the data you get from libpng.  Your
-compositing software can simply copy opaque pixels to
-the output but still has linear values for the
-non-opaque pixels.
-
-In normal compositing, where the alpha channel encodes
-partial pixel coverage (as opposed to broad area
-translucency), the inaccuracies of the 8-bit
-representation of non-opaque pixels are irrelevant.
-
-You can also try this format if your software is broken;
-it might look better.
-
-    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD;
-however, all component values,
-including the alpha channel are gamma encoded.  This is
-an appropriate format to try if your software, or more
-likely hardware, is totally broken, i.e., if it performs
-linear arithmetic directly on gamma encoded values.
-
-In most cases of broken software or hardware the bug in the final display
-manifests as a subtle halo around composited parts of the image.  You may not
-even perceive this as a halo; the composited part of the image may simply appear
-separate from the background, as though it had been cut out of paper and pasted
-on afterward.
-
-If you don't have to deal with bugs in software or hardware, or if you can fix
-them, there are three recommended ways of using png_set_alpha_mode():
-
-   png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
-       screen_gamma);
-
-You can do color correction on the result (libpng does not currently
-support color correction internally).  When you handle the alpha channel
-you need to undo the gamma encoding and multiply out the alpha.
-
-   png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
-       screen_gamma);
-   png_set_expand_16(png_ptr);
-
-If you are using the high level interface, don't call png_set_expand_16();
-instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
-
-With this mode you can't do color correction, but you can do arithmetic,
-including composition and scaling, on the data without further processing.
-
-   png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
-       screen_gamma);
-
-You can avoid the expansion to 16-bit components with this mode, but you
-lose the ability to scale the image or perform other linear arithmetic.
-All you can do is compose the result onto a matching output.  Since this
-mode is libpng-specific you also need to write your own composition
-software.
-
-If you don't need, or can't handle, the alpha channel you can call
-png_set_background() to remove it by compositing against a fixed color.  Don't
-call png_set_strip_alpha() to do this - it will leave spurious pixel values in
-transparent parts of this image.
-
-   png_set_background(png_ptr, &background_color,
-       PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
-
-The background_color is an RGB or grayscale value according to the data format
-libpng will produce for you.  Because you don't yet know the format of the PNG
-file, if you call png_set_background at this point you must arrange for the
-format produced by libpng to always have 8-bit or 16-bit components and then
-store the color as an 8-bit or 16-bit color as appropriate.  The color contains
-separate gray and RGB component values, so you can let libpng produce gray or
-RGB output according to the input format, but low bit depth grayscale images
-must always be converted to at least 8-bit format.  (Even though low bit depth
-grayscale images can't have an alpha channel they can have a transparent
-color!)
-
-You set the transforms you need later, either as flags to the high level
-interface or libpng API calls for the low level interface.  For reference the
-settings and API calls required are:
-
-8-bit values:
-   PNG_TRANSFORM_SCALE_16 | PNG_EXPAND
-   png_set_expand(png_ptr); png_set_scale_16(png_ptr);
-
-   If you must get exactly the same inaccurate results
-   produced by default in versions prior to libpng-1.5.4,
-   use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr)
-   instead.
-
-16-bit values:
-   PNG_TRANSFORM_EXPAND_16
-   png_set_expand_16(png_ptr);
-
-In either case palette image data will be expanded to RGB.  If you just want
-color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
-to the list.
-
-Calling png_set_background before the PNG file header is read will not work
-prior to libpng-1.5.4.  Because the failure may result in unexpected warnings or
-errors it is therefore much safer to call png_set_background after the head has
-been read.  Unfortunately this means that prior to libpng-1.5.4 it cannot be
-used with the high level interface.
-
-.SS The high-level read interface
-
-At this point there are two ways to proceed; through the high-level
-read interface, or through a sequence of low-level read operations.
-You can use the high-level interface if (a) you are willing to read
-the entire image into memory, and (b) the input transformations
-you want to do are limited to the following set:
-
-    PNG_TRANSFORM_IDENTITY      No transformation
-    PNG_TRANSFORM_SCALE_16      Strip 16-bit samples to
-                                8-bit accurately
-    PNG_TRANSFORM_STRIP_16      Chop 16-bit samples to
-                                8-bit less accurately
-    PNG_TRANSFORM_STRIP_ALPHA   Discard the alpha channel
-    PNG_TRANSFORM_PACKING       Expand 1, 2 and 4-bit
-                                samples to bytes
-    PNG_TRANSFORM_PACKSWAP      Change order of packed
-                                pixels to LSB first
-    PNG_TRANSFORM_EXPAND        Perform set_expand()
-    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
-    PNG_TRANSFORM_SHIFT         Normalize pixels to the
-                                sBIT depth
-    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
-                                to BGRA
-    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
-                                to AG
-    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
-                                to transparency
-    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
-    PNG_TRANSFORM_GRAY_TO_RGB   Expand grayscale samples
-                                to RGB (or GA to RGBA)
-    PNG_TRANSFORM_EXPAND_16     Expand samples to 16 bits
-
-(This excludes setting a background color, doing gamma transformation,
-quantizing, and setting filler.)  If this is the case, simply do this:
-
-    png_read_png(png_ptr, info_ptr, png_transforms, NULL)
-
-where png_transforms is an integer containing the bitwise OR of some
-set of transformation flags.  This call is equivalent to png_read_info(),
-followed the set of transformations indicated by the transform mask,
-then png_read_image(), and finally png_read_end().
-
-(The final parameter of this call is not yet used.  Someday it might point
-to transformation parameters required by some future input transform.)
-
-You must use png_transforms and not call any png_set_transform() functions
-when you use png_read_png().
-
-After you have called png_read_png(), you can retrieve the image data
-with
-
-   row_pointers = png_get_rows(png_ptr, info_ptr);
-
-where row_pointers is an array of pointers to the pixel data for each row:
-
-   png_bytep row_pointers[height];
-
-If you know your image size and pixel size ahead of time, you can allocate
-row_pointers prior to calling png_read_png() with
-
-   if (height > PNG_UINT_32_MAX/png_sizeof(png_byte))
-      png_error (png_ptr,
-          "Image is too tall to process in memory");
-
-   if (width > PNG_UINT_32_MAX/pixel_size)
-      png_error (png_ptr,
-          "Image is too wide to process in memory");
-
-   row_pointers = png_malloc(png_ptr,
-       height*png_sizeof(png_bytep));
-
-   for (int i=0; i<height, i++)
-      row_pointers[i]=NULL;  /* security precaution */
-
-   for (int i=0; i<height, i++)
-      row_pointers[i]=png_malloc(png_ptr,
-          width*pixel_size);
-
-   png_set_rows(png_ptr, info_ptr, &row_pointers);
-
-Alternatively you could allocate your image in one big block and define
-row_pointers[i] to point into the proper places in your block.
-
-If you use png_set_rows(), the application is responsible for freeing
-row_pointers (and row_pointers[i], if they were separately allocated).
-
-If you don't allocate row_pointers ahead of time, png_read_png() will
-do it, and it'll be free'ed by libpng when you call png_destroy_*().
-
-.SS The low-level read interface
-
-If you are going the low-level route, you are now ready to read all
-the file information up to the actual image data.  You do this with a
-call to png_read_info().
-
-    png_read_info(png_ptr, info_ptr);
-
-This will process all chunks up to but not including the image data.
-
-This also copies some of the data from the PNG file into the decode structure
-for use in later transformations.  Important information copied in is:
-
-1) The PNG file gamma from the gAMA chunk.  This overwrites the default value
-provided by an earlier call to png_set_gamma or png_set_alpha_mode.
-
-2) Prior to libpng-1.5.4 the background color from a bKGd chunk.  This
-damages the information provided by an earlier call to png_set_background
-resulting in unexpected behavior.  Libpng-1.5.4 no longer does this.
-
-3) The number of significant bits in each component value.  Libpng uses this to
-optimize gamma handling by reducing the internal lookup table sizes.
-
-4) The transparent color information from a tRNS chunk.  This can be modified by
-a later call to png_set_tRNS.
-
-.SS Querying the info structure
-
-Functions are used to get the information from the info_ptr once it
-has been read.  Note that these fields may not be completely filled
-in until png_read_end() has read the chunk data following the image.
-
-    png_get_IHDR(png_ptr, info_ptr, &width, &height,
-       &bit_depth, &color_type, &interlace_type,
-       &compression_type, &filter_method);
-
-    width          - holds the width of the image
-                     in pixels (up to 2^31).
-
-    height         - holds the height of the image
-                     in pixels (up to 2^31).
-
-    bit_depth      - holds the bit depth of one of the
-                     image channels.  (valid values are
-                     1, 2, 4, 8, 16 and depend also on
-                     the color_type.  See also
-                     significant bits (sBIT) below).
-
-    color_type     - describes which color/alpha channels
-                         are present.
-                     PNG_COLOR_TYPE_GRAY
-                        (bit depths 1, 2, 4, 8, 16)
-                     PNG_COLOR_TYPE_GRAY_ALPHA
-                        (bit depths 8, 16)
-                     PNG_COLOR_TYPE_PALETTE
-                        (bit depths 1, 2, 4, 8)
-                     PNG_COLOR_TYPE_RGB
-                        (bit_depths 8, 16)
-                     PNG_COLOR_TYPE_RGB_ALPHA
-                        (bit_depths 8, 16)
-
-                     PNG_COLOR_MASK_PALETTE
-                     PNG_COLOR_MASK_COLOR
-                     PNG_COLOR_MASK_ALPHA
-
-    interlace_type - (PNG_INTERLACE_NONE or
-                     PNG_INTERLACE_ADAM7)
-
-    compression_type - (must be PNG_COMPRESSION_TYPE_BASE
-                     for PNG 1.0)
-
-    filter_method  - (must be PNG_FILTER_TYPE_BASE
-                     for PNG 1.0, and can also be
-                     PNG_INTRAPIXEL_DIFFERENCING if
-                     the PNG datastream is embedded in
-                     a MNG-1.0 datastream)
-
-    Any or all of interlace_type, compression_type, or
-    filter_method can be NULL if you are
-    not interested in their values.
-
-    Note that png_get_IHDR() returns 32-bit data into
-    the application's width and height variables.
-    This is an unsafe situation if these are 16-bit
-    variables.  In such situations, the
-    png_get_image_width() and png_get_image_height()
-    functions described below are safer.
-
-    width            = png_get_image_width(png_ptr,
-                         info_ptr);
-
-    height           = png_get_image_height(png_ptr,
-                         info_ptr);
-
-    bit_depth        = png_get_bit_depth(png_ptr,
-                         info_ptr);
-
-    color_type       = png_get_color_type(png_ptr,
-                         info_ptr);
-
-    interlace_type   = png_get_interlace_type(png_ptr,
-                         info_ptr);
-
-    compression_type = png_get_compression_type(png_ptr,
-                         info_ptr);
-
-    filter_method    = png_get_filter_type(png_ptr,
-                         info_ptr);
-
-    channels = png_get_channels(png_ptr, info_ptr);
-
-    channels       - number of channels of info for the
-                     color type (valid values are 1 (GRAY,
-                     PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
-                     4 (RGB_ALPHA or RGB + filler byte))
-
-    rowbytes = png_get_rowbytes(png_ptr, info_ptr);
-
-    rowbytes       - number of bytes needed to hold a row
-
-    signature = png_get_signature(png_ptr, info_ptr);
-
-    signature      - holds the signature read from the
-                     file (if any).  The data is kept in
-                     the same offset it would be if the
-                     whole signature were read (i.e. if an
-                     application had already read in 4
-                     bytes of signature before starting
-                     libpng, the remaining 4 bytes would
-                     be in signature[4] through signature[7]
-                     (see png_set_sig_bytes())).
-
-These are also important, but their validity depends on whether the chunk
-has been read.  The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
-png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
-data has been read, or zero if it is missing.  The parameters to the
-png_get_<chunk> are set directly if they are simple data types, or a
-pointer into the info_ptr is returned for any complex types.
-
-    png_get_PLTE(png_ptr, info_ptr, &palette,
-                     &num_palette);
-
-    palette        - the palette for the file
-                     (array of png_color)
-
-    num_palette    - number of entries in the palette
-
-    png_get_gAMA(png_ptr, info_ptr, &file_gamma);
-    png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
-
-    file_gamma     - the gamma at which the file is
-                     written (PNG_INFO_gAMA)
-
-    int_file_gamma - 100,000 times the gamma at which the
-                     file is written
-
-    png_get_cHRM(png_ptr, info_ptr,  &white_x, &white_y, &red_x, &red_y,
-                     &green_x, &green_y, &blue_x, &blue_y)
-    png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z, &green_X,
-                     &green_Y, &green_Z, &blue_X, &blue_Y, &blue_Z)
-    png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x, &int_white_y,
-                     &int_red_x, &int_red_y, &int_green_x, &int_green_y,
-                     &int_blue_x, &int_blue_y)
-    png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y,
-                     &int_red_Z, &int_green_X, &int_green_Y, &int_green_Z,
-                     &int_blue_X, &int_blue_Y, &int_blue_Z)
-
-    {white,red,green,blue}_{x,y}
-                     A color space encoding specified using the chromaticities
-                     of the end points and the white point. (PNG_INFO_cHRM)
-
-    {red,green,blue}_{X,Y,Z}
-                     A color space encoding specified using the encoding end
-                     points - the CIE tristimulus specification of the intended
-                     color of the red, green and blue channels in the PNG RGB
-                     data.  The white point is simply the sum of the three end
-                     points. (PNG_INFO_cHRM)
-
-    png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
-
-    file_srgb_intent - the rendering intent (PNG_INFO_sRGB)
-                     The presence of the sRGB chunk
-                     means that the pixel data is in the
-                     sRGB color space.  This chunk also
-                     implies specific values of gAMA and
-                     cHRM.
-
-    png_get_iCCP(png_ptr, info_ptr, &name,
-       &compression_type, &profile, &proflen);
-
-    name             - The profile name.
-
-    compression_type - The compression type; always
-                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
-                       You may give NULL to this argument to
-                       ignore it.
-
-    profile          - International Color Consortium color
-                       profile data. May contain NULs.
-
-    proflen          - length of profile data in bytes.
-
-    png_get_sBIT(png_ptr, info_ptr, &sig_bit);
-
-    sig_bit        - the number of significant bits for
-                     (PNG_INFO_sBIT) each of the gray,
-                     red, green, and blue channels,
-                     whichever are appropriate for the
-                     given color type (png_color_16)
-
-    png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
-                     &num_trans, &trans_color);
-
-    trans_alpha    - array of alpha (transparency)
-                     entries for palette (PNG_INFO_tRNS)
-
-    num_trans      - number of transparent entries
-                     (PNG_INFO_tRNS)
-
-    trans_color    - graylevel or color sample values of
-                     the single transparent color for
-                     non-paletted images (PNG_INFO_tRNS)
-
-    png_get_hIST(png_ptr, info_ptr, &hist);
-                     (PNG_INFO_hIST)
-
-    hist           - histogram of palette (array of
-                     png_uint_16)
-
-    png_get_tIME(png_ptr, info_ptr, &mod_time);
-
-    mod_time       - time image was last modified
-                    (PNG_VALID_tIME)
-
-    png_get_bKGD(png_ptr, info_ptr, &background);
-
-    background     - background color (of type
-                     png_color_16p) (PNG_VALID_bKGD)
-                     valid 16-bit red, green and blue
-                     values, regardless of color_type
-
-    num_comments   = png_get_text(png_ptr, info_ptr,
-                     &text_ptr, &num_text);
-
-    num_comments   - number of comments
-
-    text_ptr       - array of png_text holding image
-                     comments
-
-    text_ptr[i].compression - type of compression used
-                 on "text" PNG_TEXT_COMPRESSION_NONE
-                           PNG_TEXT_COMPRESSION_zTXt
-                           PNG_ITXT_COMPRESSION_NONE
-                           PNG_ITXT_COMPRESSION_zTXt
-
-    text_ptr[i].key   - keyword for comment.  Must contain
-                         1-79 characters.
-
-    text_ptr[i].text  - text comments for current
-                         keyword.  Can be empty.
-
-    text_ptr[i].text_length - length of text string,
-                 after decompression, 0 for iTXt
-
-    text_ptr[i].itxt_length - length of itxt string,
-                 after decompression, 0 for tEXt/zTXt
-
-    text_ptr[i].lang  - language of comment (empty
-                         string for unknown).
-
-    text_ptr[i].lang_key  - keyword in UTF-8
-                         (empty string for unknown).
-
-    Note that the itxt_length, lang, and lang_key
-    members of the text_ptr structure only exist when the
-    library is built with iTXt chunk support.  Prior to
-    libpng-1.4.0 the library was built by default without
-    iTXt support. Also note that when iTXt is supported,
-    they contain NULL pointers when the "compression"
-    field contains PNG_TEXT_COMPRESSION_NONE or
-    PNG_TEXT_COMPRESSION_zTXt.
-
-    num_text       - number of comments (same as
-                     num_comments; you can put NULL here
-                     to avoid the duplication)
-
-    Note while png_set_text() will accept text, language,
-    and translated keywords that can be NULL pointers, the
-    structure returned by png_get_text will always contain
-    regular zero-terminated C strings.  They might be
-    empty strings but they will never be NULL pointers.
-
-    num_spalettes = png_get_sPLT(png_ptr, info_ptr,
-       &palette_ptr);
-
-    num_spalettes  - number of sPLT chunks read.
-
-    palette_ptr    - array of palette structures holding
-                     contents of one or more sPLT chunks
-                     read.
-
-    png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
-       &unit_type);
-
-    offset_x       - positive offset from the left edge
-                     of the screen (can be negative)
-
-    offset_y       - positive offset from the top edge
-                     of the screen (can be negative)
-
-    unit_type      - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
-
-    png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
-       &unit_type);
-
-    res_x          - pixels/unit physical resolution in
-                     x direction
-
-    res_y          - pixels/unit physical resolution in
-                     x direction
-
-    unit_type      - PNG_RESOLUTION_UNKNOWN,
-                     PNG_RESOLUTION_METER
-
-    png_get_sCAL(png_ptr, info_ptr, &unit, &width,
-       &height)
-
-    unit        - physical scale units (an integer)
-
-    width       - width of a pixel in physical scale units
-
-    height      - height of a pixel in physical scale units
-                 (width and height are doubles)
-
-    png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
-       &height)
-
-    unit        - physical scale units (an integer)
-
-    width       - width of a pixel in physical scale units
-                  (expressed as a string)
-
-    height      - height of a pixel in physical scale units
-                 (width and height are strings like "2.54")
-
-    num_unknown_chunks = png_get_unknown_chunks(png_ptr,
-       info_ptr, &unknowns)
-
-    unknowns          - array of png_unknown_chunk
-                        structures holding unknown chunks
-
-    unknowns[i].name  - name of unknown chunk
-
-    unknowns[i].data  - data of unknown chunk
-
-    unknowns[i].size  - size of unknown chunk's data
-
-    unknowns[i].location - position of chunk in file
-
-    The value of "i" corresponds to the order in which the
-    chunks were read from the PNG file or inserted with the
-    png_set_unknown_chunks() function.
-
-    The value of "location" is a bitwise "or" of
-
-         PNG_HAVE_IHDR  (0x01)
-         PNG_HAVE_PLTE  (0x02)
-         PNG_AFTER_IDAT (0x08)
-
-The data from the pHYs chunk can be retrieved in several convenient
-forms:
-
-    res_x = png_get_x_pixels_per_meter(png_ptr,
-       info_ptr)
-
-    res_y = png_get_y_pixels_per_meter(png_ptr,
-       info_ptr)
-
-    res_x_and_y = png_get_pixels_per_meter(png_ptr,
-       info_ptr)
-
-    res_x = png_get_x_pixels_per_inch(png_ptr,
-       info_ptr)
-
-    res_y = png_get_y_pixels_per_inch(png_ptr,
-       info_ptr)
-
-    res_x_and_y = png_get_pixels_per_inch(png_ptr,
-       info_ptr)
-
-    aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
-       info_ptr)
-
-    Each of these returns 0 [signifying "unknown"] if
-       the data is not present or if res_x is 0;
-       res_x_and_y is 0 if res_x != res_y
-
-    Note that because of the way the resolutions are
-       stored internally, the inch conversions won't
-       come out to exactly even number.  For example,
-       72 dpi is stored as 0.28346 pixels/meter, and
-       when this is retrieved it is 71.9988 dpi, so
-       be sure to round the returned value appropriately
-       if you want to display a reasonable-looking result.
-
-The data from the oFFs chunk can be retrieved in several convenient
-forms:
-
-    x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
-
-    y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
-
-    x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
-
-    y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
-
-    Each of these returns 0 [signifying "unknown" if both
-       x and y are 0] if the data is not present or if the
-       chunk is present but the unit is the pixel.  The
-       remark about inexact inch conversions applies here
-       as well, because a value in inches can't always be
-       converted to microns and back without some loss
-       of precision.
-
-For more information, see the
-PNG specification for chunk contents.  Be careful with trusting
-rowbytes, as some of the transformations could increase the space
-needed to hold a row (expand, filler, gray_to_rgb, etc.).
-See png_read_update_info(), below.
-
-A quick word about text_ptr and num_text.  PNG stores comments in
-keyword/text pairs, one pair per chunk, with no limit on the number
-of text chunks, and a 2^31 byte limit on their size.  While there are
-suggested keywords, there is no requirement to restrict the use to these
-strings.  It is strongly suggested that keywords and text be sensible
-to humans (that's the point), so don't use abbreviations.  Non-printing
-symbols are not allowed.  See the PNG specification for more details.
-There is also no requirement to have text after the keyword.
-
-Keywords should be limited to 79 Latin-1 characters without leading or
-trailing spaces, but non-consecutive spaces are allowed within the
-keyword.  It is possible to have the same keyword any number of times.
-The text_ptr is an array of png_text structures, each holding a
-pointer to a language string, a pointer to a keyword and a pointer to
-a text string.  The text string, language code, and translated
-keyword may be empty or NULL pointers.  The keyword/text
-pairs are put into the array in the order that they are received.
-However, some or all of the text chunks may be after the image, so, to
-make sure you have read all the text chunks, don't mess with these
-until after you read the stuff after the image.  This will be
-mentioned again below in the discussion that goes with png_read_end().
-
-.SS Input transformations
-
-After you've read the header information, you can set up the library
-to handle any special transformations of the image data.  The various
-ways to transform the data will be described in the order that they
-should occur.  This is important, as some of these change the color
-type and/or bit depth of the data, and some others only work on
-certain color types and bit depths.
-
-Transformations you request are ignored if they don't have any meaning for a
-particular input data format.  However some transformations can have an effect
-as a result of a previous transformation.  If you specify a contradictory set of
-transformations, for example both adding and removing the alpha channel, you
-cannot predict the final result.
-
-The color used for the transparency values should be supplied in the same
-format/depth as the current image data.  It is stored in the same format/depth
-as the image data in a tRNS chunk, so this is what libpng expects for this data.
-
-The color used for the background value depends on the need_expand argument as
-described below.
-
-Data will be decoded into the supplied row buffers packed into bytes
-unless the library has been told to transform it into another format.
-For example, 4 bit/pixel paletted or grayscale data will be returned
-2 pixels/byte with the leftmost pixel in the high-order bits of the
-byte, unless png_set_packing() is called.  8-bit RGB data will be stored
-in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
-is called to insert filler bytes, either before or after each RGB triplet.
-16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
-byte of the color value first, unless png_set_scale_16() is called to
-transform it to regular RGB RGB triplets, or png_set_filler() or
-png_set_add alpha() is called to insert filler bytes, either before or
-after each RRGGBB triplet.  Similarly, 8-bit or 16-bit grayscale data can
-be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(),
-or png_set_scale_16().
-
-The following code transforms grayscale images of less than 8 to 8 bits,
-changes paletted images to RGB, and adds a full alpha channel if there is
-transparency information in a tRNS chunk.  This is most useful on
-grayscale images with bit depths of 2 or 4 or if there is a multiple-image
-viewing application that wishes to treat all images in the same way.
-
-    if (color_type == PNG_COLOR_TYPE_PALETTE)
-        png_set_palette_to_rgb(png_ptr);
-
-    if (png_get_valid(png_ptr, info_ptr,
-        PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
-
-    if (color_type == PNG_COLOR_TYPE_GRAY &&
-        bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
-
-The first two functions are actually aliases for png_set_expand(), added
-in libpng version 1.0.4, with the function names expanded to improve code
-readability.  In some future version they may actually do different
-things.
-
-As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
-added.  It expands the sample depth without changing tRNS to alpha.
-
-As of libpng version 1.5.2, png_set_expand_16() was added.  It behaves as
-png_set_expand(); however, the resultant channels have 16 bits rather than 8.
-Use this when the output color or gray channels are made linear to avoid fairly
-severe accuracy loss.
-
-   if (bit_depth < 16)
-      png_set_expand_16(png_ptr);
-
-PNG can have files with 16 bits per channel.  If you only can handle
-8 bits per channel, this will strip the pixels down to 8-bit.
-
-    if (bit_depth == 16)
-#if PNG_LIBPNG_VER >= 10504
-       png_set_scale_16(png_ptr);
-#else
-       png_set_strip_16(png_ptr);
-#endif
-
-(The more accurate "png_set_scale_16()" API became available in libpng version
-1.5.4).
-
-If you need to process the alpha channel on the image separately from the image
-data (for example if you convert it to a bitmap mask) it is possible to have
-libpng strip the channel leaving just RGB or gray data:
-
-    if (color_type & PNG_COLOR_MASK_ALPHA)
-       png_set_strip_alpha(png_ptr);
-
-If you strip the alpha channel you need to find some other way of dealing with
-the information.  If, instead, you want to convert the image to an opaque
-version with no alpha channel use png_set_background; see below.
-
-As of libpng version 1.5.2, almost all useful expansions are supported, the
-major ommissions are conversion of grayscale to indexed images (which can be
-done trivially in the application) and conversion of indexed to grayscale (which
-can be done by a trivial manipulation of the palette.)
-
-In the following table, the 01 means grayscale with depth<8, 31 means
-indexed with depth<8, other numerals represent the color type, "T" means
-the tRNS chunk is present, A means an alpha channel is present, and O
-means tRNS or alpha is present but all pixels in the image are opaque.
-
-  FROM  01  31   0  0T  0O   2  2T  2O   3  3T  3O  4A  4O  6A  6O
-   TO
-   01    -  [G]  -   -   -   -   -   -   -   -   -   -   -   -   -
-   31   [Q]  Q  [Q] [Q] [Q]  Q   Q   Q   Q   Q   Q  [Q] [Q]  Q   Q
-    0    1   G   +   .   .   G   G   G   G   G   G   B   B  GB  GB
-   0T    lt  Gt  t   +   .   Gt  G   G   Gt  G   G   Bt  Bt GBt GBt
-   0O    lt  Gt  t   .   +   Gt  Gt  G   Gt  Gt  G   Bt  Bt GBt GBt
-    2    C   P   C   C   C   +   .   .   C   -   -  CB  CB   B   B
-   2T    Ct  -   Ct  C   C   t   +   t   -   -   -  CBt CBt  Bt  Bt
-   2O    Ct  -   Ct  C   C   t   t   +   -   -   -  CBt CBt  Bt  Bt
-    3   [Q]  p  [Q] [Q] [Q]  Q   Q   Q   +   .   .  [Q] [Q]  Q   Q
-   3T   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   +   t  [Qt][Qt] Qt  Qt
-   3O   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   t   +  [Qt][Qt] Qt  Qt
-   4A    lA  G   A   T   T   GA  GT  GT  GA  GT  GT  +   BA  G  GBA
-   4O    lA GBA  A   T   T   GA  GT  GT  GA  GT  GT  BA  +  GBA  G
-   6A    CA  PA  CA  C   C   A   T  tT   PA  P   P   C  CBA  +   BA
-   6O    CA PBA  CA  C   C   A  tT   T   PA  P   P  CBA  C   BA  +
-
-Within the matrix,
-     "+" identifies entries where 'from' and 'to' are the same.
-     "-" means the transformation is not supported.
-     "." means nothing is necessary (a tRNS chunk can just be ignored).
-     "t" means the transformation is obtained by png_set_tRNS.
-     "A" means the transformation is obtained by png_set_add_alpha().
-     "X" means the transformation is obtained by png_set_expand().
-     "1" means the transformation is obtained by
-         png_set_expand_gray_1_2_4_to_8() (and by png_set_expand() if there
-         is no transparency in the original or the final format).
-     "C" means the transformation is obtained by png_set_gray_to_rgb().
-     "G" means the transformation is obtained by png_set_rgb_to_gray().
-     "P" means the transformation is obtained by
-         png_set_expand_palette_to_rgb().
-     "p" means the transformation is obtained by png_set_packing().
-     "Q" means the transformation is obtained by png_set_quantize().
-     "T" means the transformation is obtained by png_set_tRNS_to_alpha().
-     "B" means the transformation is obtained by png_set_background(), or
-         png_strip_alpha().
-
-When an entry has multiple transforms listed all are required to cause the
-right overall transformation.  When two transforms are separated by a comma
-either will do the job.  When transforms are enclosed in [] the transform should
-do the job but this is currently unimplemented - a different format will result
-if the suggested transformations are used.
-
-In PNG files, the alpha channel in an image
-is the level of opacity.  If you need the alpha channel in an image to
-be the level of transparency instead of opacity, you can invert the
-alpha channel (or the tRNS chunk data) after it's read, so that 0 is
-fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
-images) is fully transparent, with
-
-    png_set_invert_alpha(png_ptr);
-
-PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
-they can, resulting in, for example, 8 pixels per byte for 1 bit
-files.  This code expands to 1 pixel per byte without changing the
-values of the pixels:
-
-    if (bit_depth < 8)
-       png_set_packing(png_ptr);
-
-PNG files have possible bit depths of 1, 2, 4, 8, and 16.  All pixels
-stored in a PNG image have been "scaled" or "shifted" up to the next
-higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
-to 8 bits/sample in the range [0, 255]).  However, it is also possible
-to convert the PNG pixel data back to the original bit depth of the
-image.  This call reduces the pixels back down to the original bit depth:
-
-    png_color_8p sig_bit;
-
-    if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
-       png_set_shift(png_ptr, sig_bit);
-
-PNG files store 3-color pixels in red, green, blue order.  This code
-changes the storage of the pixels to blue, green, red:
-
-    if (color_type == PNG_COLOR_TYPE_RGB ||
-        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-       png_set_bgr(png_ptr);
-
-PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
-into 4 or 8 bytes for windowing systems that need them in this format:
-
-    if (color_type == PNG_COLOR_TYPE_RGB)
-       png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
-
-where "filler" is the 8 or 16-bit number to fill with, and the location is
-either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
-you want the filler before the RGB or after.  This transformation
-does not affect images that already have full alpha channels.  To add an
-opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which
-will generate RGBA pixels.
-
-Note that png_set_filler() does not change the color type.  If you want
-to do that, you can add a true alpha channel with
-
-    if (color_type == PNG_COLOR_TYPE_RGB ||
-       color_type == PNG_COLOR_TYPE_GRAY)
-       png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
-
-where "filler" contains the alpha value to assign to each pixel.
-This function was added in libpng-1.2.7.
-
-If you are reading an image with an alpha channel, and you need the
-data as ARGB instead of the normal PNG format RGBA:
-
-    if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-       png_set_swap_alpha(png_ptr);
-
-For some uses, you may want a grayscale image to be represented as
-RGB.  This code will do that conversion:
-
-    if (color_type == PNG_COLOR_TYPE_GRAY ||
-        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-       png_set_gray_to_rgb(png_ptr);
-
-Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
-with alpha.
-
-    if (color_type == PNG_COLOR_TYPE_RGB ||
-        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-       png_set_rgb_to_gray(png_ptr, error_action, double red_weight,
-          double green_weight);
-
-    error_action = 1: silently do the conversion
-
-    error_action = 2: issue a warning if the original
-                      image has any pixel where
-                      red != green or red != blue
-
-    error_action = 3: issue an error and abort the
-                      conversion if the original
-                      image has any pixel where
-                      red != green or red != blue
-
-    red_weight:       weight of red component
-
-    green_weight:     weight of green component
-                      If either weight is negative, default
-                      weights are used.
-
-In the corresponding fixed point API the red_weight and green_weight values are
-simply scaled by 100,000:
-
-    png_set_rgb_to_gray(png_ptr, error_action, png_fixed_point red_weight,
-       png_fixed_point green_weight);
-
-If you have set error_action = 1 or 2, you can
-later check whether the image really was gray, after processing
-the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
-It will return a png_byte that is zero if the image was gray or
-1 if there were any non-gray pixels.  Background and sBIT data
-will be silently converted to grayscale, using the green channel
-data for sBIT, regardless of the error_action setting.
-
-The default values come from the PNG file cHRM chunk if present; otherwise, the
-defaults correspond to the ITU-R recommendation 709, and also the sRGB color
-space, as recommended in the Charles Poynton's Colour FAQ,
-<http://www.poynton.com/>, in section 9:
-
-   <http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
-
-    Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
-
-Previous versions of this document, 1998 through 2002, recommended a slightly
-different formula:
-
-    Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
-
-Libpng uses an integer approximation:
-
-    Y = (6968 * R + 23434 * G + 2366 * B)/32768
-
-The calculation is done in a linear colorspace, if the image gamma
-can be determined.
-
-The png_set_background() function has been described already; it tells libpng to
-composite images with alpha or simple transparency against the supplied
-background color.  For compatibility with versions of libpng earlier than
-libpng-1.5.4 it is recommended that you call the function after reading the file
-header, even if you don't want to use the color in a bKGD chunk, if one exists.
-
-If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
-you may use this color, or supply another color more suitable for
-the current display (e.g., the background color from a web page).  You
-need to tell libpng how the color is represented, both the format of the
-component values in the color (the number of bits) and the gamma encoding of the
-color.  The function takes two arguments, background_gamma_mode and need_expand
-to convey this information, however only two combinations are likely to be
-useful:
-
-    png_color_16 my_background;
-    png_color_16p image_background;
-
-    if (png_get_bKGD(png_ptr, info_ptr, &image_background))
-       png_set_background(png_ptr, image_background,
-           PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
-    else
-       png_set_background(png_ptr, &my_background,
-           PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
-
-The second call was described above - my_background is in the format of the
-final, display, output produced by libpng.  Because you now know the format of
-the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
-output and to retain palette images (the palette colors will be modified
-appropriately and the tRNS chunk removed.)  However, if you are doing this,
-take great care not to ask for transformations without checking first that
-they apply!
-
-In the first call the background color has the original bit depth and color type
-of the PNG file.  So, for palette images the color is supplied as a palette
-index and for low bit greyscale images the color is a reduced bit value in
-image_background->gray.
-
-If you didn't call png_set_gamma() before reading the file header, for example
-if you need your code to remain compatible with older versions of libpng prior
-to libpng-1.5.4, this is the place to call it.
-
-Do not call it if you called png_set_alpha_mode(); doing so will damage the
-settings put in place by png_set_alpha_mode().  (If png_set_alpha_mode() is
-supported then you can certainly do png_set_gamma() before reading the PNG
-header.)
-
-This API unconditionally sets the screen and file gamma values, so it will
-override the value in the PNG file unless it is called before the PNG file
-reading starts.  For this reason you must always call it with the PNG file
-value when you call it in this position:
-
-   if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
-      png_set_gamma(png_ptr, screen_gamma, file_gamma);
-
-   else
-      png_set_gamma(png_ptr, screen_gamma, 0.45455);
-
-If you need to reduce an RGB file to a paletted file, or if a paletted
-file has more entries then will fit on your screen, png_set_quantize()
-will do that.  Note that this is a simple match quantization that merely
-finds the closest color available.  This should work fairly well with
-optimized palettes, but fairly badly with linear color cubes.  If you
-pass a palette that is larger than maximum_colors, the file will
-reduce the number of colors in the palette so it will fit into
-maximum_colors.  If there is a histogram, libpng will use it to make
-more intelligent choices when reducing the palette.  If there is no
-histogram, it may not do as good a job.
-
-   if (color_type & PNG_COLOR_MASK_COLOR)
-   {
-      if (png_get_valid(png_ptr, info_ptr,
-          PNG_INFO_PLTE))
-      {
-         png_uint_16p histogram = NULL;
-
-         png_get_hIST(png_ptr, info_ptr,
-             &histogram);
-         png_set_quantize(png_ptr, palette, num_palette,
-            max_screen_colors, histogram, 1);
-      }
-
-      else
-      {
-         png_color std_color_cube[MAX_SCREEN_COLORS] =
-            { ... colors ... };
-
-         png_set_quantize(png_ptr, std_color_cube,
-            MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
-            NULL,0);
-      }
-   }
-
-PNG files describe monochrome as black being zero and white being one.
-The following code will reverse this (make black be one and white be
-zero):
-
-   if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
-      png_set_invert_mono(png_ptr);
-
-This function can also be used to invert grayscale and gray-alpha images:
-
-   if (color_type == PNG_COLOR_TYPE_GRAY ||
-       color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      png_set_invert_mono(png_ptr);
-
-PNG files store 16-bit pixels in network byte order (big-endian,
-ie. most significant bits first).  This code changes the storage to the
-other way (little-endian, i.e. least significant bits first, the
-way PCs store them):
-
-    if (bit_depth == 16)
-       png_set_swap(png_ptr);
-
-If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
-need to change the order the pixels are packed into bytes, you can use:
-
-    if (bit_depth < 8)
-       png_set_packswap(png_ptr);
-
-Finally, you can write your own transformation function if none of
-the existing ones meets your needs.  This is done by setting a callback
-with
-
-    png_set_read_user_transform_fn(png_ptr,
-        read_transform_fn);
-
-You must supply the function
-
-    void read_transform_fn(png_structp png_ptr, png_row_infop
-        row_info, png_bytep data)
-
-See pngtest.c for a working example.  Your function will be called
-after all of the other transformations have been processed.  Take care with
-interlaced images if you do the interlace yourself - the width of the row is the
-width in 'row_info', not the overall image width.
-
-If supported, libpng provides two information routines that you can use to find
-where you are in processing the image:
-
-   png_get_current_pass_number(png_structp png_ptr);
-   png_get_current_row_number(png_structp png_ptr);
-
-Don't try using these outside a transform callback - firstly they are only
-supported if user transforms are supported, secondly they may well return
-unexpected results unless the row is actually being processed at the moment they
-are called.
-
-With interlaced
-images the value returned is the row in the input sub-image image.  Use
-PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
-find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
-
-The discussion of interlace handling above contains more information on how to
-use these values.
-
-You can also set up a pointer to a user structure for use by your
-callback function, and you can inform libpng that your transform
-function will change the number of channels or bit depth with the
-function
-
-    png_set_user_transform_info(png_ptr, user_ptr,
-        user_depth, user_channels);
-
-The user's application, not libpng, is responsible for allocating and
-freeing any memory required for the user structure.
-
-You can retrieve the pointer via the function
-png_get_user_transform_ptr().  For example:
-
-    voidp read_user_transform_ptr =
-        png_get_user_transform_ptr(png_ptr);
-
-The last thing to handle is interlacing; this is covered in detail below,
-but you must call the function here if you want libpng to handle expansion
-of the interlaced image.
-
-    number_of_passes = png_set_interlace_handling(png_ptr);
-
-After setting the transformations, libpng can update your png_info
-structure to reflect any transformations you've requested with this
-call.
-
-    png_read_update_info(png_ptr, info_ptr);
-
-This is most useful to update the info structure's rowbytes
-field so you can use it to allocate your image memory.  This function
-will also update your palette with the correct screen_gamma and
-background if these have been given with the calls above.  You may
-only call png_read_update_info() once with a particular info_ptr.
-
-After you call png_read_update_info(), you can allocate any
-memory you need to hold the image.  The row data is simply
-raw byte data for all forms of images.  As the actual allocation
-varies among applications, no example will be given.  If you
-are allocating one large chunk, you will need to build an
-array of pointers to each row, as it will be needed for some
-of the functions below.
-
-Remember: Before you call png_read_update_info(), the png_get_*()
-functions return the values corresponding to the original PNG image.
-After you call png_read_update_info the values refer to the image
-that libpng will output.  Consequently you must call all the png_set_
-functions before you call png_read_update_info().  This is particularly
-important for png_set_interlace_handling() - if you are going to call
-png_read_update_info() you must call png_set_interlace_handling() before
-it unless you want to receive interlaced output.
-
-.SS Reading image data
-
-After you've allocated memory, you can read the image data.
-The simplest way to do this is in one function call.  If you are
-allocating enough memory to hold the whole image, you can just
-call png_read_image() and libpng will read in all the image data
-and put it in the memory area supplied.  You will need to pass in
-an array of pointers to each row.
-
-This function automatically handles interlacing, so you don't
-need to call png_set_interlace_handling() (unless you call
-png_read_update_info()) or call this function multiple times, or any
-of that other stuff necessary with png_read_rows().
-
-   png_read_image(png_ptr, row_pointers);
-
-where row_pointers is:
-
-   png_bytep row_pointers[height];
-
-You can point to void or char or whatever you use for pixels.
-
-If you don't want to read in the whole image at once, you can
-use png_read_rows() instead.  If there is no interlacing (check
-interlace_type == PNG_INTERLACE_NONE), this is simple:
-
-    png_read_rows(png_ptr, row_pointers, NULL,
-        number_of_rows);
-
-where row_pointers is the same as in the png_read_image() call.
-
-If you are doing this just one row at a time, you can do this with
-a single row_pointer instead of an array of row_pointers:
-
-    png_bytep row_pointer = row;
-    png_read_row(png_ptr, row_pointer, NULL);
-
-If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
-get somewhat harder.  The only current (PNG Specification version 1.2)
-interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
-a somewhat complicated 2D interlace scheme, known as Adam7, that
-breaks down an image into seven smaller images of varying size, based
-on an 8x8 grid.  This number is defined (from libpng 1.5) as
-PNG_INTERLACE_ADAM7_PASSES in png.h
-
-libpng can fill out those images or it can give them to you "as is".
-It is almost always better to have libpng handle the interlacing for you.
-If you want the images filled out, there are two ways to do that.  The one
-mentioned in the PNG specification is to expand each pixel to cover
-those pixels that have not been read yet (the "rectangle" method).
-This results in a blocky image for the first pass, which gradually
-smooths out as more pixels are read.  The other method is the "sparkle"
-method, where pixels are drawn only in their final locations, with the
-rest of the image remaining whatever colors they were initialized to
-before the start of the read.  The first method usually looks better,
-but tends to be slower, as there are more pixels to put in the rows.
-
-If, as is likely, you want libpng to expand the images, call this before
-calling png_start_read_image() or png_read_update_info():
-
-    if (interlace_type == PNG_INTERLACE_ADAM7)
-       number_of_passes
-           = png_set_interlace_handling(png_ptr);
-
-This will return the number of passes needed.  Currently, this is seven,
-but may change if another interlace type is added.  This function can be
-called even if the file is not interlaced, where it will return one pass.
-You then need to read the whole image 'number_of_passes' times.  Each time
-will distribute the pixels from the current pass to the correct place in
-the output image, so you need to supply the same rows to png_read_rows in
-each pass.
-
-If you are not going to display the image after each pass, but are
-going to wait until the entire image is read in, use the sparkle
-effect.  This effect is faster and the end result of either method
-is exactly the same.  If you are planning on displaying the image
-after each pass, the "rectangle" effect is generally considered the
-better looking one.
-
-If you only want the "sparkle" effect, just call png_read_rows() as
-normal, with the third parameter NULL.  Make sure you make pass over
-the image number_of_passes times, and you don't change the data in the
-rows between calls.  You can change the locations of the data, just
-not the data.  Each pass only writes the pixels appropriate for that
-pass, and assumes the data from previous passes is still valid.
-
-    png_read_rows(png_ptr, row_pointers, NULL,
-        number_of_rows);
-
-If you only want the first effect (the rectangles), do the same as
-before except pass the row buffer in the third parameter, and leave
-the second parameter NULL.
-
-    png_read_rows(png_ptr, NULL, row_pointers,
-        number_of_rows);
-
-If you don't want libpng to handle the interlacing details, just call
-png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
-Each of the images is a valid image by itself, however you will almost
-certainly need to distribute the pixels from each sub-image to the
-correct place.  This is where everything gets very tricky.
-
-If you want to retrieve the separate images you must pass the correct
-number of rows to each successive call of png_read_rows().  The calculation
-gets pretty complicated for small images, where some sub-images may
-not even exist because either their width or height ends up zero.
-libpng provides two macros to help you in 1.5 and later versions:
-
-   png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
-   png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
-
-Respectively these tell you the width and height of the sub-image
-corresponding to the numbered pass.  'pass' is in in the range 0 to 6 -
-this can be confusing because the specification refers to the same passes
-as 1 to 7!  Be careful, you must check both the width and height before
-calling png_read_rows() and not call it for that pass if either is zero.
-
-You can, of course, read each sub-image row by row.  If you want to
-produce optimal code to make a pixel-by-pixel transformation of an
-interlaced image this is the best approach; read each row of each pass,
-transform it, and write it out to a new interlaced image.
-
-If you want to de-interlace the image yourself libpng provides further
-macros to help that tell you where to place the pixels in the output image.
-Because the interlacing scheme is rectangular - sub-image pixels are always
-arranged on a rectangular grid - all you need to know for each pass is the
-starting column and row in the output image of the first pixel plus the
-spacing between each pixel.  As of libpng 1.5 there are four macros to
-retrieve this information:
-
-   png_uint_32 x = PNG_PASS_START_COL(pass);
-   png_uint_32 y = PNG_PASS_START_ROW(pass);
-   png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
-   png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
-
-These allow you to write the obvious loop:
-
-   png_uint_32 input_y = 0;
-   png_uint_32 output_y = PNG_PASS_START_ROW(pass);
-
-   while (output_y < output_image_height)
-   {
-      png_uint_32 input_x = 0;
-      png_uint_32 output_x = PNG_PASS_START_COL(pass);
-
-      while (output_x < output_image_width)
-      {
-         image[output_y][output_x] =
-             subimage[pass][input_y][input_x++];
-
-         output_x += xStep;
-      }
-
-      ++input_y;
-      output_y += yStep;
-   }
-
-Notice that the steps between successive output rows and columns are
-returned as shifts.  This is possible because the pixels in the subimages
-are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
-image.  In practice you may need to directly calculate the output coordinate
-given an input coordinate.  libpng provides two further macros for this
-purpose:
-
-   png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
-   png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
-
-Finally a pair of macros are provided to tell you if a particular image
-row or column appears in a given pass:
-
-   int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
-   int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
-
-Bear in mind that you will probably also need to check the width and height
-of the pass in addition to the above to be sure the pass even exists!
-
-With any luck you are convinced by now that you don't want to do your own
-interlace handling.  In reality normally the only good reason for doing this
-is if you are processing PNG files on a pixel-by-pixel basis and don't want
-to load the whole file into memory when it is interlaced.
-
-libpng includes a test program, pngvalid, that illustrates reading and
-writing of interlaced images.  If you can't get interlacing to work in your
-code and don't want to leave it to libpng (the recommended approach), see
-how pngvalid.c does it.
-
-.SS Finishing a sequential read
-
-After you are finished reading the image through the
-low-level interface, you can finish reading the file.  If you are
-interested in comments or time, which may be stored either before or
-after the image data, you should pass the separate png_info struct if
-you want to keep the comments from before and after the image
-separate.
-
-    png_infop end_info = png_create_info_struct(png_ptr);
-
-    if (!end_info)
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-           (png_infopp)NULL);
-       return (ERROR);
-    }
-
-   png_read_end(png_ptr, end_info);
-
-If you are not interested, you should still call png_read_end()
-but you can pass NULL, avoiding the need to create an end_info structure.
-
-   png_read_end(png_ptr, (png_infop)NULL);
-
-If you don't call png_read_end(), then your file pointer will be
-left pointing to the first chunk after the last IDAT, which is probably
-not what you want if you expect to read something beyond the end of
-the PNG datastream.
-
-When you are done, you can free all memory allocated by libpng like this:
-
-   png_destroy_read_struct(&png_ptr, &info_ptr,
-       &end_info);
-
-or, if you didn't create an end_info structure,
-
-   png_destroy_read_struct(&png_ptr, &info_ptr,
-       (png_infopp)NULL);
-
-It is also possible to individually free the info_ptr members that
-point to libpng-allocated storage with the following function:
-
-    png_free_data(png_ptr, info_ptr, mask, seq)
-
-    mask - identifies data to be freed, a mask
-           containing the bitwise OR of one or
-           more of
-             PNG_FREE_PLTE, PNG_FREE_TRNS,
-             PNG_FREE_HIST, PNG_FREE_ICCP,
-             PNG_FREE_PCAL, PNG_FREE_ROWS,
-             PNG_FREE_SCAL, PNG_FREE_SPLT,
-             PNG_FREE_TEXT, PNG_FREE_UNKN,
-           or simply PNG_FREE_ALL
-
-    seq  - sequence number of item to be freed
-           (-1 for all items)
-
-This function may be safely called when the relevant storage has
-already been freed, or has not yet been allocated, or was allocated
-by the user and not by libpng,  and will in those cases do nothing.
-The "seq" parameter is ignored if only one item of the selected data
-type, such as PLTE, is allowed.  If "seq" is not -1, and multiple items
-are allowed for the data type identified in the mask, such as text or
-sPLT, only the n'th item in the structure is freed, where n is "seq".
-
-The default behavior is only to free data that was allocated internally
-by libpng.  This can be changed, so that libpng will not free the data,
-or so that it will free data that was allocated by the user with png_malloc()
-or png_zalloc() and passed in via a png_set_*() function, with
-
-    png_data_freer(png_ptr, info_ptr, freer, mask)
-
-    freer  - one of
-               PNG_DESTROY_WILL_FREE_DATA
-               PNG_SET_WILL_FREE_DATA
-               PNG_USER_WILL_FREE_DATA
-
-    mask   - which data elements are affected
-             same choices as in png_free_data()
-
-This function only affects data that has already been allocated.
-You can call this function after reading the PNG data but before calling
-any png_set_*() functions, to control whether the user or the png_set_*()
-function is responsible for freeing any existing data that might be present,
-and again after the png_set_*() functions to control whether the user
-or png_destroy_*() is supposed to free the data.  When the user assumes
-responsibility for libpng-allocated data, the application must use
-png_free() to free it, and when the user transfers responsibility to libpng
-for data that the user has allocated, the user must have used png_malloc()
-or png_zalloc() to allocate it.
-
-If you allocated your row_pointers in a single block, as suggested above in
-the description of the high level read interface, you must not transfer
-responsibility for freeing it to the png_set_rows or png_read_destroy function,
-because they would also try to free the individual row_pointers[i].
-
-If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
-separately, do not transfer responsibility for freeing text_ptr to libpng,
-because when libpng fills a png_text structure it combines these members with
-the key member, and png_free_data() will free only text_ptr.key.  Similarly,
-if you transfer responsibility for free'ing text_ptr from libpng to your
-application, your application must not separately free those members.
-
-The png_free_data() function will turn off the "valid" flag for anything
-it frees.  If you need to turn the flag off for a chunk that was freed by
-your application instead of by libpng, you can use
-
-    png_set_invalid(png_ptr, info_ptr, mask);
-
-    mask - identifies the chunks to be made invalid,
-           containing the bitwise OR of one or
-           more of
-             PNG_INFO_gAMA, PNG_INFO_sBIT,
-             PNG_INFO_cHRM, PNG_INFO_PLTE,
-             PNG_INFO_tRNS, PNG_INFO_bKGD,
-             PNG_INFO_hIST, PNG_INFO_pHYs,
-             PNG_INFO_oFFs, PNG_INFO_tIME,
-             PNG_INFO_pCAL, PNG_INFO_sRGB,
-             PNG_INFO_iCCP, PNG_INFO_sPLT,
-             PNG_INFO_sCAL, PNG_INFO_IDAT
-
-For a more compact example of reading a PNG image, see the file example.c.
-
-.SS Reading PNG files progressively
-
-The progressive reader is slightly different then the non-progressive
-reader.  Instead of calling png_read_info(), png_read_rows(), and
-png_read_end(), you make one call to png_process_data(), which calls
-callbacks when it has the info, a row, or the end of the image.  You
-set up these callbacks with png_set_progressive_read_fn().  You don't
-have to worry about the input/output functions of libpng, as you are
-giving the library the data directly in png_process_data().  I will
-assume that you have read the section on reading PNG files above,
-so I will only highlight the differences (although I will show
-all of the code).
-
-png_structp png_ptr;
-png_infop info_ptr;
-
- /*  An example code fragment of how you would
-     initialize the progressive reader in your
-     application. */
- int
- initialize_png_reader()
- {
-    png_ptr = png_create_read_struct
-        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-         user_error_fn, user_warning_fn);
-
-    if (!png_ptr)
-        return (ERROR);
-
-    info_ptr = png_create_info_struct(png_ptr);
-
-    if (!info_ptr)
-    {
-       png_destroy_read_struct(&png_ptr,
-          (png_infopp)NULL, (png_infopp)NULL);
-       return (ERROR);
-    }
-
-    if (setjmp(png_jmpbuf(png_ptr)))
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-          (png_infopp)NULL);
-       return (ERROR);
-    }
-
-    /* This one's new.  You can provide functions
-       to be called when the header info is valid,
-       when each row is completed, and when the image
-       is finished.  If you aren't using all functions,
-       you can specify NULL parameters.  Even when all
-       three functions are NULL, you need to call
-       png_set_progressive_read_fn().  You can use
-       any struct as the user_ptr (cast to a void pointer
-       for the function call), and retrieve the pointer
-       from inside the callbacks using the function
-
-          png_get_progressive_ptr(png_ptr);
-
-       which will return a void pointer, which you have
-       to cast appropriately.
-     */
-    png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
-        info_callback, row_callback, end_callback);
-
-    return 0;
- }
-
- /* A code fragment that you call as you receive blocks
-   of data */
- int
- process_data(png_bytep buffer, png_uint_32 length)
- {
-    if (setjmp(png_jmpbuf(png_ptr)))
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-           (png_infopp)NULL);
-       return (ERROR);
-    }
-
-    /* This one's new also.  Simply give it a chunk
-       of data from the file stream (in order, of
-       course).  On machines with segmented memory
-       models machines, don't give it any more than
-       64K.  The library seems to run fine with sizes
-       of 4K. Although you can give it much less if
-       necessary (I assume you can give it chunks of
-       1 byte, I haven't tried less then 256 bytes
-       yet).  When this function returns, you may
-       want to display any rows that were generated
-       in the row callback if you don't already do
-       so there.
-     */
-    png_process_data(png_ptr, info_ptr, buffer, length);
-
-    /* At this point you can call png_process_data_skip if
-       you want to handle data the library will skip yourself;
-       it simply returns the number of bytes to skip (and stops
-       libpng skipping that number of bytes on the next
-       png_process_data call).
-    return 0;
- }
-
- /* This function is called (as set by
-    png_set_progressive_read_fn() above) when enough data
-    has been supplied so all of the header has been
-    read.
- */
- void
- info_callback(png_structp png_ptr, png_infop info)
- {
-    /* Do any setup here, including setting any of
-       the transformations mentioned in the Reading
-       PNG files section.  For now, you _must_ call
-       either png_start_read_image() or
-       png_read_update_info() after all the
-       transformations are set (even if you don't set
-       any).  You may start getting rows before
-       png_process_data() returns, so this is your
-       last chance to prepare for that.
-
-       This is where you turn on interlace handling,
-       assuming you don't want to do it yourself.
-
-       If you need to you can stop the processing of
-       your original input data at this point by calling
-       png_process_data_pause.  This returns the number
-       of unprocessed bytes from the last png_process_data
-       call - it is up to you to ensure that the next call
-       sees these bytes again.  If you don't want to bother
-       with this you can get libpng to cache the unread
-       bytes by setting the 'save' parameter (see png.h) but
-       then libpng will have to copy the data internally.
-     */
- }
-
- /* This function is called when each row of image
-    data is complete */
- void
- row_callback(png_structp png_ptr, png_bytep new_row,
-    png_uint_32 row_num, int pass)
- {
-    /* If the image is interlaced, and you turned
-       on the interlace handler, this function will
-       be called for every row in every pass.  Some
-       of these rows will not be changed from the
-       previous pass.  When the row is not changed,
-       the new_row variable will be NULL.  The rows
-       and passes are called in order, so you don't
-       really need the row_num and pass, but I'm
-       supplying them because it may make your life
-       easier.
-
-       If you did not turn on interlace handling then
-       the callback is called for each row of each
-       sub-image when the image is interlaced.  In this
-       case 'row_num' is the row in the sub-image, not
-       the row in the output image as it is in all other
-       cases.
-
-       For the non-NULL rows of interlaced images when
-       you have switched on libpng interlace handling,
-       you must call png_progressive_combine_row()
-       passing in the row and the old row.  You can
-       call this function for NULL rows (it will just
-       return) and for non-interlaced images (it just
-       does the memcpy for you) if it will make the
-       code easier.  Thus, you can just do this for
-       all cases if you switch on interlace handling;
-     */
-
-        png_progressive_combine_row(png_ptr, old_row,
-          new_row);
-
-    /* where old_row is what was displayed for
-       previously for the row.  Note that the first
-       pass (pass == 0, really) will completely cover
-       the old row, so the rows do not have to be
-       initialized.  After the first pass (and only
-       for interlaced images), you will have to pass
-       the current row, and the function will combine
-       the old row and the new row.
-
-       You can also call png_process_data_pause in this
-       callback - see above.
-    */
- }
-
- void
- end_callback(png_structp png_ptr, png_infop info)
- {
-    /* This function is called after the whole image
-       has been read, including any chunks after the
-       image (up to and including the IEND).  You
-       will usually have the same info chunk as you
-       had in the header, although some data may have
-       been added to the comments and time fields.
-
-       Most people won't do much here, perhaps setting
-       a flag that marks the image as finished.
-     */
- }
-
-
-
-.SH IV. Writing
-
-Much of this is very similar to reading.  However, everything of
-importance is repeated here, so you won't have to constantly look
-back up in the reading section to understand writing.
-
-.SS Setup
-
-You will want to do the I/O initialization before you get into libpng,
-so if it doesn't work, you don't have anything to undo. If you are not
-using the standard I/O functions, you will need to replace them with
-custom writing functions.  See the discussion under Customizing libpng.
-
-    FILE *fp = fopen(file_name, "wb");
-
-    if (!fp)
-       return (ERROR);
-
-Next, png_struct and png_info need to be allocated and initialized.
-As these can be both relatively large, you may not want to store these
-on the stack, unless you have stack space to spare.  Of course, you
-will want to check if they return NULL.  If you are also reading,
-you won't want to name your read structure and your write structure
-both "png_ptr"; you can call them anything you like, such as
-"read_ptr" and "write_ptr".  Look at pngtest.c, for example.
-
-    png_structp png_ptr = png_create_write_struct
-       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-        user_error_fn, user_warning_fn);
-
-    if (!png_ptr)
-       return (ERROR);
-
-    png_infop info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr)
-    {
-       png_destroy_write_struct(&png_ptr,
-           (png_infopp)NULL);
-       return (ERROR);
-    }
-
-If you want to use your own memory allocation routines,
-define PNG_USER_MEM_SUPPORTED and use
-png_create_write_struct_2() instead of png_create_write_struct():
-
-    png_structp png_ptr = png_create_write_struct_2
-       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
-        user_error_fn, user_warning_fn, (png_voidp)
-        user_mem_ptr, user_malloc_fn, user_free_fn);
-
-After you have these structures, you will need to set up the
-error handling.  When libpng encounters an error, it expects to
-longjmp() back to your routine.  Therefore, you will need to call
-setjmp() and pass the png_jmpbuf(png_ptr).  If you
-write the file from different routines, you will need to update
-the png_jmpbuf(png_ptr) every time you enter a new routine that will
-call a png_*() function.  See your documentation of setjmp/longjmp
-for your compiler for more information on setjmp/longjmp.  See
-the discussion on libpng error handling in the Customizing Libpng
-section below for more information on the libpng error handling.
-
-    if (setjmp(png_jmpbuf(png_ptr)))
-    {
-    png_destroy_write_struct(&png_ptr, &info_ptr);
-       fclose(fp);
-       return (ERROR);
-    }
-    ...
-    return;
-
-If you would rather avoid the complexity of setjmp/longjmp issues,
-you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT() which defaults to abort().
-
-You can #define PNG_ABORT() to a function that does something
-more useful than abort(), as long as your function does not
-return.
-
-Now you need to set up the output code.  The default for libpng is to
-use the C function fwrite().  If you use this, you will need to pass a
-valid FILE * in the function png_init_io().  Be sure that the file is
-opened in binary mode.  Again, if you wish to handle writing data in
-another way, see the discussion on libpng I/O handling in the Customizing
-Libpng section below.
-
-    png_init_io(png_ptr, fp);
-
-If you are embedding your PNG into a datastream such as MNG, and don't
-want libpng to write the 8-byte signature, or if you have already
-written the signature in your application, use
-
-    png_set_sig_bytes(png_ptr, 8);
-
-to inform libpng that it should not write a signature.
-
-.SS Write callbacks
-
-At this point, you can set up a callback function that will be
-called after each row has been written, which you can use to control
-a progress meter or the like.  It's demonstrated in pngtest.c.
-You must supply a function
-
-    void write_row_callback(png_structp png_ptr, png_uint_32 row,
-       int pass);
-    {
-      /* put your code here */
-    }
-
-(You can give it another name that you like instead of "write_row_callback")
-
-To inform libpng about your function, use
-
-    png_set_write_status_fn(png_ptr, write_row_callback);
-
-When this function is called the row has already been completely processed and
-it has also been written out.  The 'row' and 'pass' refer to the next row to be
-handled.  For the
-non-interlaced case the row that was just handled is simply one less than the
-passed in row number, and pass will always be 0.  For the interlaced case the
-same applies unless the row value is 0, in which case the row just handled was
-the last one from one of the preceding passes.  Because interlacing may skip a
-pass you cannot be sure that the preceding pass is just 'pass-1', if you really
-need to know what the last pass is record (row,pass) from the callback and use
-the last recorded value each time.
-
-As with the user transform you can find the output row using the
-PNG_ROW_FROM_PASS_ROW macro.
-
-You now have the option of modifying how the compression library will
-run.  The following functions are mainly for testing, but may be useful
-in some cases, like if you need to write PNG files extremely fast and
-are willing to give up some compression, or if you want to get the
-maximum possible compression at the expense of slower writing.  If you
-have no special needs in this area, let the library do what it wants by
-not calling this function at all, as it has been tuned to deliver a good
-speed/compression ratio. The second parameter to png_set_filter() is
-the filter method, for which the only valid values are 0 (as of the
-July 1999 PNG specification, version 1.2) or 64 (if you are writing
-a PNG datastream that is to be embedded in a MNG datastream).  The third
-parameter is a flag that indicates which filter type(s) are to be tested
-for each scanline.  See the PNG specification for details on the specific
-filter types.
-
-
-    /* turn on or off filtering, and/or choose
-       specific filters.  You can use either a single
-       PNG_FILTER_VALUE_NAME or the bitwise OR of one
-       or more PNG_FILTER_NAME masks.
-     */
-    png_set_filter(png_ptr, 0,
-       PNG_FILTER_NONE  | PNG_FILTER_VALUE_NONE |
-       PNG_FILTER_SUB   | PNG_FILTER_VALUE_SUB  |
-       PNG_FILTER_UP    | PNG_FILTER_VALUE_UP   |
-       PNG_FILTER_AVG   | PNG_FILTER_VALUE_AVG  |
-       PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
-       PNG_ALL_FILTERS);
-
-If an application wants to start and stop using particular filters during
-compression, it should start out with all of the filters (to ensure that
-the previous row of pixels will be stored in case it's needed later),
-and then add and remove them after the start of compression.
-
-If you are writing a PNG datastream that is to be embedded in a MNG
-datastream, the second parameter can be either 0 or 64.
-
-The png_set_compression_*() functions interface to the zlib compression
-library, and should mostly be ignored unless you really know what you are
-doing.  The only generally useful call is png_set_compression_level()
-which changes how much time zlib spends on trying to compress the image
-data.  See the Compression Library (zlib.h and algorithm.txt, distributed
-with zlib) for details on the compression levels.
-
-    #include zlib.h
-
-    /* Set the zlib compression level */
-    png_set_compression_level(png_ptr,
-        Z_BEST_COMPRESSION);
-
-    /* Set other zlib parameters for compressing IDAT */
-    png_set_compression_mem_level(png_ptr, 8);
-    png_set_compression_strategy(png_ptr,
-        Z_DEFAULT_STRATEGY);
-    png_set_compression_window_bits(png_ptr, 15);
-    png_set_compression_method(png_ptr, 8);
-    png_set_compression_buffer_size(png_ptr, 8192)
-
-    /* Set zlib parameters for text compression
-     * If you don't call these, the parameters
-     * fall back on those defined for IDAT chunks
-     */
-    png_set_text_compression_mem_level(png_ptr, 8);
-    png_set_text_compression_strategy(png_ptr,
-        Z_DEFAULT_STRATEGY);
-    png_set_text_compression_window_bits(png_ptr, 15);
-    png_set_text_compression_method(png_ptr, 8);
-
-.SS Setting the contents of info for output
-
-You now need to fill in the png_info structure with all the data you
-wish to write before the actual image.  Note that the only thing you
-are allowed to write after the image is the text chunks and the time
-chunk (as of PNG Specification 1.2, anyway).  See png_write_end() and
-the latest PNG specification for more information on that.  If you
-wish to write them before the image, fill them in now, and flag that
-data as being valid.  If you want to wait until after the data, don't
-fill them until png_write_end().  For all the fields in png_info and
-their data types, see png.h.  For explanations of what the fields
-contain, see the PNG specification.
-
-Some of the more important parts of the png_info are:
-
-    png_set_IHDR(png_ptr, info_ptr, width, height,
-       bit_depth, color_type, interlace_type,
-       compression_type, filter_method)
-
-    width          - holds the width of the image
-                     in pixels (up to 2^31).
-
-    height         - holds the height of the image
-                     in pixels (up to 2^31).
-
-    bit_depth      - holds the bit depth of one of the
-                     image channels.
-                     (valid values are 1, 2, 4, 8, 16
-                     and depend also on the
-                     color_type.  See also significant
-                     bits (sBIT) below).
-
-    color_type     - describes which color/alpha
-                     channels are present.
-                     PNG_COLOR_TYPE_GRAY
-                        (bit depths 1, 2, 4, 8, 16)
-                     PNG_COLOR_TYPE_GRAY_ALPHA
-                        (bit depths 8, 16)
-                     PNG_COLOR_TYPE_PALETTE
-                        (bit depths 1, 2, 4, 8)
-                     PNG_COLOR_TYPE_RGB
-                        (bit_depths 8, 16)
-                     PNG_COLOR_TYPE_RGB_ALPHA
-                        (bit_depths 8, 16)
-
-                     PNG_COLOR_MASK_PALETTE
-                     PNG_COLOR_MASK_COLOR
-                     PNG_COLOR_MASK_ALPHA
-
-    interlace_type - PNG_INTERLACE_NONE or
-                     PNG_INTERLACE_ADAM7
-
-    compression_type - (must be
-                     PNG_COMPRESSION_TYPE_DEFAULT)
-
-    filter_method  - (must be PNG_FILTER_TYPE_DEFAULT
-                     or, if you are writing a PNG to
-                     be embedded in a MNG datastream,
-                     can also be
-                     PNG_INTRAPIXEL_DIFFERENCING)
-
-If you call png_set_IHDR(), the call must appear before any of the
-other png_set_*() functions, because they might require access to some of
-the IHDR settings.  The remaining png_set_*() functions can be called
-in any order.
-
-If you wish, you can reset the compression_type, interlace_type, or
-filter_method later by calling png_set_IHDR() again; if you do this, the
-width, height, bit_depth, and color_type must be the same in each call.
-
-    png_set_PLTE(png_ptr, info_ptr, palette,
-       num_palette);
-
-    palette        - the palette for the file
-                     (array of png_color)
-    num_palette    - number of entries in the palette
-
-    png_set_gAMA(png_ptr, info_ptr, file_gamma);
-    png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
-
-    file_gamma     - the gamma at which the image was
-                     created (PNG_INFO_gAMA)
-
-    int_file_gamma - 100,000 times the gamma at which
-                     the image was created
-
-    png_set_cHRM(png_ptr, info_ptr,  white_x, white_y, red_x, red_y,
-                     green_x, green_y, blue_x, blue_y)
-    png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X,
-                     green_Y, green_Z, blue_X, blue_Y, blue_Z)
-    png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y,
-                     int_red_x, int_red_y, int_green_x, int_green_y,
-                     int_blue_x, int_blue_y)
-    png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y,
-                     int_red_Z, int_green_X, int_green_Y, int_green_Z,
-                     int_blue_X, int_blue_Y, int_blue_Z)
-
-    {white,red,green,blue}_{x,y}
-                     A color space encoding specified using the chromaticities
-                     of the end points and the white point.
-
-    {red,green,blue}_{X,Y,Z}
-                     A color space encoding specified using the encoding end
-                     points - the CIE tristimulus specification of the intended
-                     color of the red, green and blue channels in the PNG RGB
-                     data.  The white point is simply the sum of the three end
-                     points.
-
-    png_set_sRGB(png_ptr, info_ptr, srgb_intent);
-
-    srgb_intent    - the rendering intent
-                     (PNG_INFO_sRGB) The presence of
-                     the sRGB chunk means that the pixel
-                     data is in the sRGB color space.
-                     This chunk also implies specific
-                     values of gAMA and cHRM.  Rendering
-                     intent is the CSS-1 property that
-                     has been defined by the International
-                     Color Consortium
-                     (http://www.color.org).
-                     It can be one of
-                     PNG_sRGB_INTENT_SATURATION,
-                     PNG_sRGB_INTENT_PERCEPTUAL,
-                     PNG_sRGB_INTENT_ABSOLUTE, or
-                     PNG_sRGB_INTENT_RELATIVE.
-
-
-    png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
-       srgb_intent);
-
-    srgb_intent    - the rendering intent
-                     (PNG_INFO_sRGB) The presence of the
-                     sRGB chunk means that the pixel
-                     data is in the sRGB color space.
-                     This function also causes gAMA and
-                     cHRM chunks with the specific values
-                     that are consistent with sRGB to be
-                     written.
-
-    png_set_iCCP(png_ptr, info_ptr, name, compression_type,
-                       profile, proflen);
-
-    name             - The profile name.
-
-    compression_type - The compression type; always
-                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
-                       You may give NULL to this argument to
-                       ignore it.
-
-    profile          - International Color Consortium color
-                       profile data. May contain NULs.
-
-    proflen          - length of profile data in bytes.
-
-    png_set_sBIT(png_ptr, info_ptr, sig_bit);
-
-    sig_bit        - the number of significant bits for
-                     (PNG_INFO_sBIT) each of the gray, red,
-                     green, and blue channels, whichever are
-                     appropriate for the given color type
-                     (png_color_16)
-
-    png_set_tRNS(png_ptr, info_ptr, trans_alpha,
-       num_trans, trans_color);
-
-    trans_alpha    - array of alpha (transparency)
-                     entries for palette (PNG_INFO_tRNS)
-
-    num_trans      - number of transparent entries
-                     (PNG_INFO_tRNS)
-
-    trans_color    - graylevel or color sample values
-                     (in order red, green, blue) of the
-                     single transparent color for
-                     non-paletted images (PNG_INFO_tRNS)
-
-    png_set_hIST(png_ptr, info_ptr, hist);
-
-    hist           - histogram of palette (array of
-                     png_uint_16) (PNG_INFO_hIST)
-
-    png_set_tIME(png_ptr, info_ptr, mod_time);
-
-    mod_time       - time image was last modified
-                     (PNG_VALID_tIME)
-
-    png_set_bKGD(png_ptr, info_ptr, background);
-
-    background     - background color (of type
-                     png_color_16p) (PNG_VALID_bKGD)
-
-    png_set_text(png_ptr, info_ptr, text_ptr, num_text);
-
-    text_ptr       - array of png_text holding image
-                     comments
-
-    text_ptr[i].compression - type of compression used
-                 on "text" PNG_TEXT_COMPRESSION_NONE
-                           PNG_TEXT_COMPRESSION_zTXt
-                           PNG_ITXT_COMPRESSION_NONE
-                           PNG_ITXT_COMPRESSION_zTXt
-    text_ptr[i].key   - keyword for comment.  Must contain
-                 1-79 characters.
-    text_ptr[i].text  - text comments for current
-                         keyword.  Can be NULL or empty.
-    text_ptr[i].text_length - length of text string,
-                 after decompression, 0 for iTXt
-    text_ptr[i].itxt_length - length of itxt string,
-                 after decompression, 0 for tEXt/zTXt
-    text_ptr[i].lang  - language of comment (NULL or
-                         empty for unknown).
-    text_ptr[i].translated_keyword  - keyword in UTF-8 (NULL
-                         or empty for unknown).
-
-    Note that the itxt_length, lang, and lang_key
-    members of the text_ptr structure only exist when the
-    library is built with iTXt chunk support.  Prior to
-    libpng-1.4.0 the library was built by default without
-    iTXt support. Also note that when iTXt is supported,
-    they contain NULL pointers when the "compression"
-    field contains PNG_TEXT_COMPRESSION_NONE or
-    PNG_TEXT_COMPRESSION_zTXt.
-
-    num_text       - number of comments
-
-    png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
-       num_spalettes);
-
-    palette_ptr    - array of png_sPLT_struct structures
-                     to be added to the list of palettes
-                     in the info structure.
-    num_spalettes  - number of palette structures to be
-                     added.
-
-    png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
-        unit_type);
-
-    offset_x  - positive offset from the left
-                     edge of the screen
-
-    offset_y  - positive offset from the top
-                     edge of the screen
-
-    unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
-
-    png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
-        unit_type);
-
-    res_x       - pixels/unit physical resolution
-                  in x direction
-
-    res_y       - pixels/unit physical resolution
-                  in y direction
-
-    unit_type   - PNG_RESOLUTION_UNKNOWN,
-                  PNG_RESOLUTION_METER
-
-    png_set_sCAL(png_ptr, info_ptr, unit, width, height)
-
-    unit        - physical scale units (an integer)
-
-    width       - width of a pixel in physical scale units
-
-    height      - height of a pixel in physical scale units
-                  (width and height are doubles)
-
-    png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
-
-    unit        - physical scale units (an integer)
-
-    width       - width of a pixel in physical scale units
-                  expressed as a string
-
-    height      - height of a pixel in physical scale units
-                 (width and height are strings like "2.54")
-
-    png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
-       num_unknowns)
-
-    unknowns          - array of png_unknown_chunk
-                        structures holding unknown chunks
-    unknowns[i].name  - name of unknown chunk
-    unknowns[i].data  - data of unknown chunk
-    unknowns[i].size  - size of unknown chunk's data
-    unknowns[i].location - position to write chunk in file
-                           0: do not write chunk
-                           PNG_HAVE_IHDR: before PLTE
-                           PNG_HAVE_PLTE: before IDAT
-                           PNG_AFTER_IDAT: after IDAT
-
-The "location" member is set automatically according to
-what part of the output file has already been written.
-You can change its value after calling png_set_unknown_chunks()
-as demonstrated in pngtest.c.  Within each of the "locations",
-the chunks are sequenced according to their position in the
-structure (that is, the value of "i", which is the order in which
-the chunk was either read from the input file or defined with
-png_set_unknown_chunks).
-
-A quick word about text and num_text.  text is an array of png_text
-structures.  num_text is the number of valid structures in the array.
-Each png_text structure holds a language code, a keyword, a text value,
-and a compression type.
-
-The compression types have the same valid numbers as the compression
-types of the image data.  Currently, the only valid number is zero.
-However, you can store text either compressed or uncompressed, unlike
-images, which always have to be compressed.  So if you don't want the
-text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
-Because tEXt and zTXt chunks don't have a language field, if you
-specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
-any language code or translated keyword will not be written out.
-
-Until text gets around a few hundred bytes, it is not worth compressing it.
-After the text has been written out to the file, the compression type
-is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
-so that it isn't written out again at the end (in case you are calling
-png_write_end() with the same struct).
-
-The keywords that are given in the PNG Specification are:
-
-    Title            Short (one line) title or
-                     caption for image
-
-    Author           Name of image's creator
-
-    Description      Description of image (possibly long)
-
-    Copyright        Copyright notice
-
-    Creation Time    Time of original image creation
-                     (usually RFC 1123 format, see below)
-
-    Software         Software used to create the image
-
-    Disclaimer       Legal disclaimer
-
-    Warning          Warning of nature of content
-
-    Source           Device used to create the image
-
-    Comment          Miscellaneous comment; conversion
-                     from other image format
-
-The keyword-text pairs work like this.  Keywords should be short
-simple descriptions of what the comment is about.  Some typical
-keywords are found in the PNG specification, as is some recommendations
-on keywords.  You can repeat keywords in a file.  You can even write
-some text before the image and some after.  For example, you may want
-to put a description of the image before the image, but leave the
-disclaimer until after, so viewers working over modem connections
-don't have to wait for the disclaimer to go over the modem before
-they start seeing the image.  Finally, keywords should be full
-words, not abbreviations.  Keywords and text are in the ISO 8859-1
-(Latin-1) character set (a superset of regular ASCII) and can not
-contain NUL characters, and should not contain control or other
-unprintable characters.  To make the comments widely readable, stick
-with basic ASCII, and avoid machine specific character set extensions
-like the IBM-PC character set.  The keyword must be present, but
-you can leave off the text string on non-compressed pairs.
-Compressed pairs must have a text string, as only the text string
-is compressed anyway, so the compression would be meaningless.
-
-PNG supports modification time via the png_time structure.  Two
-conversion routines are provided, png_convert_from_time_t() for
-time_t and png_convert_from_struct_tm() for struct tm.  The
-time_t routine uses gmtime().  You don't have to use either of
-these, but if you wish to fill in the png_time structure directly,
-you should provide the time in universal time (GMT) if possible
-instead of your local time.  Note that the year number is the full
-year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
-that months start with 1.
-
-If you want to store the time of the original image creation, you should
-use a plain tEXt chunk with the "Creation Time" keyword.  This is
-necessary because the "creation time" of a PNG image is somewhat vague,
-depending on whether you mean the PNG file, the time the image was
-created in a non-PNG format, a still photo from which the image was
-scanned, or possibly the subject matter itself.  In order to facilitate
-machine-readable dates, it is recommended that the "Creation Time"
-tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
-although this isn't a requirement.  Unlike the tIME chunk, the
-"Creation Time" tEXt chunk is not expected to be automatically changed
-by the software.  To facilitate the use of RFC 1123 dates, a function
-png_convert_to_rfc1123(png_timep) is provided to convert from PNG
-time to an RFC 1123 format string.
-
-.SS Writing unknown chunks
-
-You can use the png_set_unknown_chunks function to queue up chunks
-for writing.  You give it a chunk name, raw data, and a size; that's
-all there is to it.  The chunks will be written by the next following
-png_write_info_before_PLTE, png_write_info, or png_write_end function.
-Any chunks previously read into the info structure's unknown-chunk
-list will also be written out in a sequence that satisfies the PNG
-specification's ordering rules.
-
-.SS The high-level write interface
-
-At this point there are two ways to proceed; through the high-level
-write interface, or through a sequence of low-level write operations.
-You can use the high-level interface if your image data is present
-in the info structure.  All defined output
-transformations are permitted, enabled by the following masks.
-
-    PNG_TRANSFORM_IDENTITY      No transformation
-    PNG_TRANSFORM_PACKING       Pack 1, 2 and 4-bit samples
-    PNG_TRANSFORM_PACKSWAP      Change order of packed
-                                pixels to LSB first
-    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
-    PNG_TRANSFORM_SHIFT         Normalize pixels to the
-                                sBIT depth
-    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
-                                to BGRA
-    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
-                                to AG
-    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
-                                to transparency
-    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
-    PNG_TRANSFORM_STRIP_FILLER        Strip out filler
-                                      bytes (deprecated).
-    PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
-                                      filler bytes
-    PNG_TRANSFORM_STRIP_FILLER_AFTER  Strip out trailing
-                                      filler bytes
-
-If you have valid image data in the info structure (you can use
-png_set_rows() to put image data in the info structure), simply do this:
-
-    png_write_png(png_ptr, info_ptr, png_transforms, NULL)
-
-where png_transforms is an integer containing the bitwise OR of some set of
-transformation flags.  This call is equivalent to png_write_info(),
-followed the set of transformations indicated by the transform mask,
-then png_write_image(), and finally png_write_end().
-
-(The final parameter of this call is not yet used.  Someday it might point
-to transformation parameters required by some future output transform.)
-
-You must use png_transforms and not call any png_set_transform() functions
-when you use png_write_png().
-
-.SS The low-level write interface
-
-If you are going the low-level route instead, you are now ready to
-write all the file information up to the actual image data.  You do
-this with a call to png_write_info().
-
-    png_write_info(png_ptr, info_ptr);
-
-Note that there is one transformation you may need to do before
-png_write_info().  In PNG files, the alpha channel in an image is the
-level of opacity.  If your data is supplied as a level of transparency,
-you can invert the alpha channel before you write it, so that 0 is
-fully transparent and 255 (in 8-bit or paletted images) or 65535
-(in 16-bit images) is fully opaque, with
-
-    png_set_invert_alpha(png_ptr);
-
-This must appear before png_write_info() instead of later with the
-other transformations because in the case of paletted images the tRNS
-chunk data has to be inverted before the tRNS chunk is written.  If
-your image is not a paletted image, the tRNS data (which in such cases
-represents a single color to be rendered as transparent) won't need to
-be changed, and you can safely do this transformation after your
-png_write_info() call.
-
-If you need to write a private chunk that you want to appear before
-the PLTE chunk when PLTE is present, you can write the PNG info in
-two steps, and insert code to write your own chunk between them:
-
-    png_write_info_before_PLTE(png_ptr, info_ptr);
-    png_set_unknown_chunks(png_ptr, info_ptr, ...);
-    png_write_info(png_ptr, info_ptr);
-
-After you've written the file information, you can set up the library
-to handle any special transformations of the image data.  The various
-ways to transform the data will be described in the order that they
-should occur.  This is important, as some of these change the color
-type and/or bit depth of the data, and some others only work on
-certain color types and bit depths.  Even though each transformation
-checks to see if it has data that it can do something with, you should
-make sure to only enable a transformation if it will be valid for the
-data.  For example, don't swap red and blue on grayscale data.
-
-PNG files store RGB pixels packed into 3 or 6 bytes.  This code tells
-the library to strip input data that has 4 or 8 bytes per pixel down
-to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
-bytes per pixel).
-
-    png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
-
-where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
-PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
-is stored XRGB or RGBX.
-
-PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
-they can, resulting in, for example, 8 pixels per byte for 1 bit files.
-If the data is supplied at 1 pixel per byte, use this code, which will
-correctly pack the pixels into a single byte:
-
-    png_set_packing(png_ptr);
-
-PNG files reduce possible bit depths to 1, 2, 4, 8, and 16.  If your
-data is of another bit depth, you can write an sBIT chunk into the
-file so that decoders can recover the original data if desired.
-
-    /* Set the true bit depth of the image data */
-    if (color_type & PNG_COLOR_MASK_COLOR)
-    {
-       sig_bit.red = true_bit_depth;
-       sig_bit.green = true_bit_depth;
-       sig_bit.blue = true_bit_depth;
-    }
-
-    else
-    {
-       sig_bit.gray = true_bit_depth;
-    }
-
-    if (color_type & PNG_COLOR_MASK_ALPHA)
-    {
-       sig_bit.alpha = true_bit_depth;
-    }
-
-    png_set_sBIT(png_ptr, info_ptr, &sig_bit);
-
-If the data is stored in the row buffer in a bit depth other than
-one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
-this will scale the values to appear to be the correct bit depth as
-is required by PNG.
-
-    png_set_shift(png_ptr, &sig_bit);
-
-PNG files store 16-bit pixels in network byte order (big-endian,
-ie. most significant bits first).  This code would be used if they are
-supplied the other way (little-endian, i.e. least significant bits
-first, the way PCs store them):
-
-    if (bit_depth > 8)
-       png_set_swap(png_ptr);
-
-If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
-need to change the order the pixels are packed into bytes, you can use:
-
-    if (bit_depth < 8)
-       png_set_packswap(png_ptr);
-
-PNG files store 3 color pixels in red, green, blue order.  This code
-would be used if they are supplied as blue, green, red:
-
-    png_set_bgr(png_ptr);
-
-PNG files describe monochrome as black being zero and white being
-one. This code would be used if the pixels are supplied with this reversed
-(black being one and white being zero):
-
-    png_set_invert_mono(png_ptr);
-
-Finally, you can write your own transformation function if none of
-the existing ones meets your needs.  This is done by setting a callback
-with
-
-    png_set_write_user_transform_fn(png_ptr,
-       write_transform_fn);
-
-You must supply the function
-
-    void write_transform_fn(png_structp png_ptr, png_row_infop
-       row_info, png_bytep data)
-
-See pngtest.c for a working example.  Your function will be called
-before any of the other transformations are processed.  If supported
-libpng also supplies an information routine that may be called from
-your callback:
-
-   png_get_current_row_number(png_ptr);
-   png_get_current_pass_number(png_ptr);
-
-This returns the current row passed to the transform.  With interlaced
-images the value returned is the row in the input sub-image image.  Use
-PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
-find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
-
-The discussion of interlace handling above contains more information on how to
-use these values.
-
-You can also set up a pointer to a user structure for use by your
-callback function.
-
-    png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
-
-The user_channels and user_depth parameters of this function are ignored
-when writing; you can set them to zero as shown.
-
-You can retrieve the pointer via the function png_get_user_transform_ptr().
-For example:
-
-    voidp write_user_transform_ptr =
-       png_get_user_transform_ptr(png_ptr);
-
-It is possible to have libpng flush any pending output, either manually,
-or automatically after a certain number of lines have been written.  To
-flush the output stream a single time call:
-
-    png_write_flush(png_ptr);
-
-and to have libpng flush the output stream periodically after a certain
-number of scanlines have been written, call:
-
-    png_set_flush(png_ptr, nrows);
-
-Note that the distance between rows is from the last time png_write_flush()
-was called, or the first row of the image if it has never been called.
-So if you write 50 lines, and then png_set_flush 25, it will flush the
-output on the next scanline, and every 25 lines thereafter, unless
-png_write_flush() is called before 25 more lines have been written.
-If nrows is too small (less than about 10 lines for a 640 pixel wide
-RGB image) the image compression may decrease noticeably (although this
-may be acceptable for real-time applications).  Infrequent flushing will
-only degrade the compression performance by a few percent over images
-that do not use flushing.
-
-.SS Writing the image data
-
-That's it for the transformations.  Now you can write the image data.
-The simplest way to do this is in one function call.  If you have the
-whole image in memory, you can just call png_write_image() and libpng
-will write the image.  You will need to pass in an array of pointers to
-each row.  This function automatically handles interlacing, so you don't
-need to call png_set_interlace_handling() or call this function multiple
-times, or any of that other stuff necessary with png_write_rows().
-
-    png_write_image(png_ptr, row_pointers);
-
-where row_pointers is:
-
-    png_byte *row_pointers[height];
-
-You can point to void or char or whatever you use for pixels.
-
-If you don't want to write the whole image at once, you can
-use png_write_rows() instead.  If the file is not interlaced,
-this is simple:
-
-    png_write_rows(png_ptr, row_pointers,
-       number_of_rows);
-
-row_pointers is the same as in the png_write_image() call.
-
-If you are just writing one row at a time, you can do this with
-a single row_pointer instead of an array of row_pointers:
-
-    png_bytep row_pointer = row;
-
-    png_write_row(png_ptr, row_pointer);
-
-When the file is interlaced, things can get a good deal more complicated.
-The only currently (as of the PNG Specification version 1.2, dated July
-1999) defined interlacing scheme for PNG files is the "Adam7" interlace
-scheme, that breaks down an image into seven smaller images of varying
-size.  libpng will build these images for you, or you can do them
-yourself.  If you want to build them yourself, see the PNG specification
-for details of which pixels to write when.
-
-If you don't want libpng to handle the interlacing details, just
-use png_set_interlace_handling() and call png_write_rows() the
-correct number of times to write all the sub-images
-(png_set_interlace_handling() returns the number of sub-images.)
-
-If you want libpng to build the sub-images, call this before you start
-writing any rows:
-
-    number_of_passes = png_set_interlace_handling(png_ptr);
-
-This will return the number of passes needed.  Currently, this is seven,
-but may change if another interlace type is added.
-
-Then write the complete image number_of_passes times.
-
-    png_write_rows(png_ptr, row_pointers, number_of_rows);
-
-Think carefully before you write an interlaced image.  Typically code that
-reads such images reads all the image data into memory, uncompressed, before
-doing any processing.  Only code that can display an image on the fly can
-take advantage of the interlacing and even then the image has to be exactly
-the correct size for the output device, because scaling an image requires
-adjacent pixels and these are not available until all the passes have been
-read.
-
-If you do write an interlaced image you will hardly ever need to handle
-the interlacing yourself.  Call png_set_interlace_handling() and use the
-approach described above.
-
-The only time it is conceivable that you will really need to write an
-interlaced image pass-by-pass is when you have read one pass by pass and
-made some pixel-by-pixel transformation to it, as described in the read
-code above.  In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
-to determine the size of each sub-image in turn and simply write the rows
-you obtained from the read code.
-
-.SS Finishing a sequential write
-
-After you are finished writing the image, you should finish writing
-the file.  If you are interested in writing comments or time, you should
-pass an appropriately filled png_info pointer.  If you are not interested,
-you can pass NULL.
-
-    png_write_end(png_ptr, info_ptr);
-
-When you are done, you can free all memory used by libpng like this:
-
-    png_destroy_write_struct(&png_ptr, &info_ptr);
-
-It is also possible to individually free the info_ptr members that
-point to libpng-allocated storage with the following function:
-
-    png_free_data(png_ptr, info_ptr, mask, seq)
-
-    mask  - identifies data to be freed, a mask
-            containing the bitwise OR of one or
-            more of
-              PNG_FREE_PLTE, PNG_FREE_TRNS,
-              PNG_FREE_HIST, PNG_FREE_ICCP,
-              PNG_FREE_PCAL, PNG_FREE_ROWS,
-              PNG_FREE_SCAL, PNG_FREE_SPLT,
-              PNG_FREE_TEXT, PNG_FREE_UNKN,
-            or simply PNG_FREE_ALL
-
-    seq   - sequence number of item to be freed
-            (-1 for all items)
-
-This function may be safely called when the relevant storage has
-already been freed, or has not yet been allocated, or was allocated
-by the user  and not by libpng,  and will in those cases do nothing.
-The "seq" parameter is ignored if only one item of the selected data
-type, such as PLTE, is allowed.  If "seq" is not -1, and multiple items
-are allowed for the data type identified in the mask, such as text or
-sPLT, only the n'th item in the structure is freed, where n is "seq".
-
-If you allocated data such as a palette that you passed in to libpng
-with png_set_*, you must not free it until just before the call to
-png_destroy_write_struct().
-
-The default behavior is only to free data that was allocated internally
-by libpng.  This can be changed, so that libpng will not free the data,
-or so that it will free data that was allocated by the user with png_malloc()
-or png_zalloc() and passed in via a png_set_*() function, with
-
-    png_data_freer(png_ptr, info_ptr, freer, mask)
-
-    freer  - one of
-               PNG_DESTROY_WILL_FREE_DATA
-               PNG_SET_WILL_FREE_DATA
-               PNG_USER_WILL_FREE_DATA
-
-    mask   - which data elements are affected
-             same choices as in png_free_data()
-
-For example, to transfer responsibility for some data from a read structure
-to a write structure, you could use
-
-    png_data_freer(read_ptr, read_info_ptr,
-       PNG_USER_WILL_FREE_DATA,
-       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
-
-    png_data_freer(write_ptr, write_info_ptr,
-       PNG_DESTROY_WILL_FREE_DATA,
-       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
-
-thereby briefly reassigning responsibility for freeing to the user but
-immediately afterwards reassigning it once more to the write_destroy
-function.  Having done this, it would then be safe to destroy the read
-structure and continue to use the PLTE, tRNS, and hIST data in the write
-structure.
-
-This function only affects data that has already been allocated.
-You can call this function before calling after the png_set_*() functions
-to control whether the user or png_destroy_*() is supposed to free the data.
-When the user assumes responsibility for libpng-allocated data, the
-application must use
-png_free() to free it, and when the user transfers responsibility to libpng
-for data that the user has allocated, the user must have used png_malloc()
-or png_zalloc() to allocate it.
-
-If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
-separately, do not transfer responsibility for freeing text_ptr to libpng,
-because when libpng fills a png_text structure it combines these members with
-the key member, and png_free_data() will free only text_ptr.key.  Similarly,
-if you transfer responsibility for free'ing text_ptr from libpng to your
-application, your application must not separately free those members.
-For a more compact example of writing a PNG image, see the file example.c.
-
-.SH V. Modifying/Customizing libpng:
-
-There are two issues here.  The first is changing how libpng does
-standard things like memory allocation, input/output, and error handling.
-The second deals with more complicated things like adding new chunks,
-adding new transformations, and generally changing how libpng works.
-Both of those are compile-time issues; that is, they are generally
-determined at the time the code is written, and there is rarely a need
-to provide the user with a means of changing them.
-
-Memory allocation, input/output, and error handling
-
-All of the memory allocation, input/output, and error handling in libpng
-goes through callbacks that are user-settable.  The default routines are
-in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively.  To change
-these functions, call the appropriate png_set_*_fn() function.
-
-Memory allocation is done through the functions png_malloc(), png_calloc(),
-and png_free().  These currently just call the standard C functions.
-png_calloc() calls png_malloc() and then clears the newly
-allocated memory to zero.  There is limited support for certain systems
-with segmented memory architectures and the types of pointers declared by
-png.h match this; you will have to use appropriate pointers in your
-application.  Since it is
-unlikely that the method of handling memory allocation on a platform
-will change between applications, these functions must be modified in
-the library at compile time.  If you prefer to use a different method
-of allocating and freeing data, you can use png_create_read_struct_2() or
-png_create_write_struct_2() to register your own functions as described
-above.  These functions also provide a void pointer that can be retrieved
-via
-
-    mem_ptr=png_get_mem_ptr(png_ptr);
-
-Your replacement memory functions must have prototypes as follows:
-
-    png_voidp malloc_fn(png_structp png_ptr,
-       png_alloc_size_t size);
-
-    void free_fn(png_structp png_ptr, png_voidp ptr);
-
-Your malloc_fn() must return NULL in case of failure.  The png_malloc()
-function will normally call png_error() if it receives a NULL from the
-system memory allocator or from your replacement malloc_fn().
-
-Your free_fn() will never be called with a NULL ptr, since libpng's
-png_free() checks for NULL before calling free_fn().
-
-Input/Output in libpng is done through png_read() and png_write(),
-which currently just call fread() and fwrite().  The FILE * is stored in
-png_struct and is initialized via png_init_io().  If you wish to change
-the method of I/O, the library supplies callbacks that you can set
-through the function png_set_read_fn() and png_set_write_fn() at run
-time, instead of calling the png_init_io() function.  These functions
-also provide a void pointer that can be retrieved via the function
-png_get_io_ptr().  For example:
-
-    png_set_read_fn(png_structp read_ptr,
-        voidp read_io_ptr, png_rw_ptr read_data_fn)
-
-    png_set_write_fn(png_structp write_ptr,
-        voidp write_io_ptr, png_rw_ptr write_data_fn,
-        png_flush_ptr output_flush_fn);
-
-    voidp read_io_ptr = png_get_io_ptr(read_ptr);
-    voidp write_io_ptr = png_get_io_ptr(write_ptr);
-
-The replacement I/O functions must have prototypes as follows:
-
-    void user_read_data(png_structp png_ptr,
-        png_bytep data, png_size_t length);
-
-    void user_write_data(png_structp png_ptr,
-        png_bytep data, png_size_t length);
-
-    void user_flush_data(png_structp png_ptr);
-
-The user_read_data() function is responsible for detecting and
-handling end-of-data errors.
-
-Supplying NULL for the read, write, or flush functions sets them back
-to using the default C stream functions, which expect the io_ptr to
-point to a standard *FILE structure.  It is probably a mistake
-to use NULL for one of write_data_fn and output_flush_fn but not both
-of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
-It is an error to read from a write stream, and vice versa.
-
-Error handling in libpng is done through png_error() and png_warning().
-Errors handled through png_error() are fatal, meaning that png_error()
-should never return to its caller.  Currently, this is handled via
-setjmp() and longjmp() (unless you have compiled libpng with
-PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
-but you could change this to do things like exit() if you should wish,
-as long as your function does not return.
-
-On non-fatal errors, png_warning() is called
-to print a warning message, and then control returns to the calling code.
-By default png_error() and png_warning() print a message on stderr via
-fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
-(because you don't want the messages) or PNG_NO_STDIO defined (because
-fprintf() isn't available).  If you wish to change the behavior of the error
-functions, you will need to set up your own message callbacks.  These
-functions are normally supplied at the time that the png_struct is created.
-It is also possible to redirect errors and warnings to your own replacement
-functions after png_create_*_struct() has been called by calling:
-
-    png_set_error_fn(png_structp png_ptr,
-        png_voidp error_ptr, png_error_ptr error_fn,
-        png_error_ptr warning_fn);
-
-    png_voidp error_ptr = png_get_error_ptr(png_ptr);
-
-If NULL is supplied for either error_fn or warning_fn, then the libpng
-default function will be used, calling fprintf() and/or longjmp() if a
-problem is encountered.  The replacement error functions should have
-parameters as follows:
-
-    void user_error_fn(png_structp png_ptr,
-        png_const_charp error_msg);
-
-    void user_warning_fn(png_structp png_ptr,
-        png_const_charp warning_msg);
-
-The motivation behind using setjmp() and longjmp() is the C++ throw and
-catch exception handling methods.  This makes the code much easier to write,
-as there is no need to check every return code of every function call.
-However, there are some uncertainties about the status of local variables
-after a longjmp, so the user may want to be careful about doing anything
-after setjmp returns non-zero besides returning itself.  Consult your
-compiler documentation for more details.  For an alternative approach, you
-may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net),
-which is illustrated in pngvalid.c and in contrib/visupng.
-
-.SS Custom chunks
-
-If you need to read or write custom chunks, you may need to get deeper
-into the libpng code.  The library now has mechanisms for storing
-and writing chunks of unknown type; you can even declare callbacks
-for custom chunks.  However, this may not be good enough if the
-library code itself needs to know about interactions between your
-chunk and existing `intrinsic' chunks.
-
-If you need to write a new intrinsic chunk, first read the PNG
-specification. Acquire a first level of understanding of how it works.
-Pay particular attention to the sections that describe chunk names,
-and look at how other chunks were designed, so you can do things
-similarly.  Second, check out the sections of libpng that read and
-write chunks.  Try to find a chunk that is similar to yours and use
-it as a template.  More details can be found in the comments inside
-the code.  It is best to handle private or unknown chunks in a generic method,
-via callback functions, instead of by modifying libpng functions. This
-is illustrated in pngtest.c, which uses a callback function to handle a
-private "vpAg" chunk and the new "sTER" chunk, which are both unknown to
-libpng.
-
-If you wish to write your own transformation for the data, look through
-the part of the code that does the transformations, and check out some of
-the simpler ones to get an idea of how they work.  Try to find a similar
-transformation to the one you want to add and copy off of it.  More details
-can be found in the comments inside the code itself.
-
-.SS Configuring for 16-bit platforms
-
-You will want to look into zconf.h to tell zlib (and thus libpng) that
-it cannot allocate more then 64K at a time.  Even if you can, the memory
-won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.
-
-.SS Configuring for DOS
-
-For DOS users who only have access to the lower 640K, you will
-have to limit zlib's memory usage via a png_set_compression_mem_level()
-call.  See zlib.h or zconf.h in the zlib library for more information.
-
-.SS Configuring for Medium Model
-
-Libpng's support for medium model has been tested on most of the popular
-compilers.  Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
-defined, and FAR gets defined to far in pngconf.h, and you should be
-all set.  Everything in the library (except for zlib's structure) is
-expecting far data.  You must use the typedefs with the p or pp on
-the end for pointers (or at least look at them and be careful).  Make
-note that the rows of data are defined as png_bytepp, which is
-an "unsigned char far * far *".
-
-.SS Configuring for gui/windowing platforms:
-
-You will need to write new error and warning functions that use the GUI
-interface, as described previously, and set them to be the error and
-warning functions at the time that png_create_*_struct() is called,
-in order to have them available during the structure initialization.
-They can be changed later via png_set_error_fn().  On some compilers,
-you may also have to change the memory allocators (png_malloc, etc.).
-
-.SS Configuring for compiler xxx:
-
-All includes for libpng are in pngconf.h.  If you need to add, change
-or delete an include, this is the place to do it.
-The includes that are not needed outside libpng are placed in pngpriv.h,
-which is only used by the routines inside libpng itself.
-The files in libpng proper only include pngpriv.h and png.h, which
-%14%in turn includes pngconf.h.
-in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
-As of libpng-1.5.0, pngpriv.h also includes three other private header
-files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
-that previously appeared in the public headers.
-
-.SS Configuring zlib:
-
-There are special functions to configure the compression.  Perhaps the
-most useful one changes the compression level, which currently uses
-input compression values in the range 0 - 9.  The library normally
-uses the default compression level (Z_DEFAULT_COMPRESSION = 6).  Tests
-have shown that for a large majority of images, compression values in
-the range 3-6 compress nearly as well as higher levels, and do so much
-faster.  For online applications it may be desirable to have maximum speed
-(Z_BEST_SPEED = 1).  With versions of zlib after v0.99, you can also
-specify no compression (Z_NO_COMPRESSION = 0), but this would create
-files larger than just storing the raw bitmap.  You can specify the
-compression level by calling:
-
-    #include zlib.h
-    png_set_compression_level(png_ptr, level);
-
-Another useful one is to reduce the memory level used by the library.
-The memory level defaults to 8, but it can be lowered if you are
-short on memory (running DOS, for example, where you only have 640K).
-Note that the memory level does have an effect on compression; among
-other things, lower levels will result in sections of incompressible
-data being emitted in smaller stored blocks, with a correspondingly
-larger relative overhead of up to 15% in the worst case.
-
-    #include zlib.h
-    png_set_compression_mem_level(png_ptr, level);
-
-The other functions are for configuring zlib.  They are not recommended
-for normal use and may result in writing an invalid PNG file.  See
-zlib.h for more information on what these mean.
-
-    #include zlib.h
-    png_set_compression_strategy(png_ptr,
-        strategy);
-
-    png_set_compression_window_bits(png_ptr,
-        window_bits);
-
-    png_set_compression_method(png_ptr, method);
-
-    png_set_compression_buffer_size(png_ptr, size);
-
-As of libpng version 1.5.4, additional APIs became
-available to set these separately for non-IDAT
-compressed chunks such as zTXt, iTXt, and iCCP:
-
-    #include zlib.h
-    #if PNG_LIBPNG_VER <= 10504
-    png_set_text_compression_level(png_ptr, level);
-
-    png_set_text_compression_mem_level(png_ptr, level);
-
-    png_set_text_compression_strategy(png_ptr,
-        strategy);
-
-    png_set_text_compression_window_bits(png_ptr,
-        window_bits);
-
-    png_set_text_compression_method(png_ptr, method);
-    #endif
-
-.SS Controlling row filtering
-
-If you want to control whether libpng uses filtering or not, which
-filters are used, and how it goes about picking row filters, you
-can call one of these functions.  The selection and configuration
-of row filters can have a significant impact on the size and
-encoding speed and a somewhat lesser impact on the decoding speed
-of an image.  Filtering is enabled by default for RGB and grayscale
-images (with and without alpha), but not for paletted images nor
-for any images with bit depths less than 8 bits/pixel.
-
-The 'method' parameter sets the main filtering method, which is
-currently only '0' in the PNG 1.2 specification.  The 'filters'
-parameter sets which filter(s), if any, should be used for each
-scanline.  Possible values are PNG_ALL_FILTERS and PNG_NO_FILTERS
-to turn filtering on and off, respectively.
-
-Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
-PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
-ORed together with '|' to specify one or more filters to use.
-These filters are described in more detail in the PNG specification.
-If you intend to change the filter type during the course of writing
-the image, you should start with flags set for all of the filters
-you intend to use so that libpng can initialize its internal
-structures appropriately for all of the filter types.  (Note that this
-means the first row must always be adaptively filtered, because libpng
-currently does not allocate the filter buffers until png_write_row()
-is called for the first time.)
-
-    filters = PNG_FILTER_NONE | PNG_FILTER_SUB
-              PNG_FILTER_UP | PNG_FILTER_AVG |
-              PNG_FILTER_PAETH | PNG_ALL_FILTERS;
-
-    png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
-       filters);
-              The second parameter can also be
-              PNG_INTRAPIXEL_DIFFERENCING if you are
-              writing a PNG to be embedded in a MNG
-              datastream.  This parameter must be the
-              same as the value of filter_method used
-              in png_set_IHDR().
-
-It is also possible to influence how libpng chooses from among the
-available filters.  This is done in one or both of two ways - by
-telling it how important it is to keep the same filter for successive
-rows, and by telling it the relative computational costs of the filters.
-
-    double weights[3] = {1.5, 1.3, 1.1},
-       costs[PNG_FILTER_VALUE_LAST] =
-       {1.0, 1.3, 1.3, 1.5, 1.7};
-
-    png_set_filter_heuristics(png_ptr,
-       PNG_FILTER_HEURISTIC_WEIGHTED, 3,
-       weights, costs);
-
-The weights are multiplying factors that indicate to libpng that the
-row filter should be the same for successive rows unless another row filter
-is that many times better than the previous filter.  In the above example,
-if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a
-"sum of absolute differences" 1.5 x 1.3 times higher than other filters
-and still be chosen, while the NONE filter could have a sum 1.1 times
-higher than other filters and still be chosen.  Unspecified weights are
-taken to be 1.0, and the specified weights should probably be declining
-like those above in order to emphasize recent filters over older filters.
-
-The filter costs specify for each filter type a relative decoding cost
-to be considered when selecting row filters.  This means that filters
-with higher costs are less likely to be chosen over filters with lower
-costs, unless their "sum of absolute differences" is that much smaller.
-The costs do not necessarily reflect the exact computational speeds of
-the various filters, since this would unduly influence the final image
-size.
-
-Note that the numbers above were invented purely for this example and
-are given only to help explain the function usage.  Little testing has
-been done to find optimum values for either the costs or the weights.
-
-.SS Removing unwanted object code
-
-There are a bunch of #define's in pngconf.h that control what parts of
-libpng are compiled.  All the defines end in _SUPPORTED.  If you are
-never going to use a capability, you can change the #define to #undef
-before recompiling libpng and save yourself code and data space, or
-you can turn off individual capabilities with defines that begin with
-PNG_NO_.
-
-In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
-
-You can also turn all of the transforms and ancillary chunk capabilities
-off en masse with compiler directives that define
-PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
-or all four,
-along with directives to turn on any of the capabilities that you do
-want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the extra
-transformations but still leave the library fully capable of reading
-and writing PNG files with all known public chunks. Use of the
-PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
-that is incapable of reading or writing ancillary chunks.  If you are
-not using the progressive reading capability, you can turn that off
-with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
-capability, which you'll still have).
-
-All the reading and writing specific code are in separate files, so the
-linker should only grab the files it needs.  However, if you want to
-make sure, or if you are building a stand alone library, all the
-reading files start with "pngr" and all the writing files start with "pngw".
-The files that don't match either (like png.c, pngtrans.c, etc.)
-are used for both reading and writing, and always need to be included.
-The progressive reader is in pngpread.c
-
-If you are creating or distributing a dynamically linked library (a .so
-or DLL file), you should not remove or disable any parts of the library,
-as this will cause applications linked with different versions of the
-library to fail if they call functions not available in your library.
-The size of the library itself should not be an issue, because only
-those sections that are actually used will be loaded into memory.
-
-.SS Requesting debug printout
-
-The macro definition PNG_DEBUG can be used to request debugging
-printout.  Set it to an integer value in the range 0 to 3.  Higher
-numbers result in increasing amounts of debugging information.  The
-information is printed to the "stderr" file, unless another file
-name is specified in the PNG_DEBUG_FILE macro definition.
-
-When PNG_DEBUG > 0, the following functions (macros) become available:
-
-   png_debug(level, message)
-   png_debug1(level, message, p1)
-   png_debug2(level, message, p1, p2)
-
-in which "level" is compared to PNG_DEBUG to decide whether to print
-the message, "message" is the formatted string to be printed,
-and p1 and p2 are parameters that are to be embedded in the string
-according to printf-style formatting directives.  For example,
-
-   png_debug1(2, "foo=%d\n", foo);
-
-is expanded to
-
-   if (PNG_DEBUG > 2)
-      fprintf(PNG_DEBUG_FILE, "foo=%d\n", foo);
-
-When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
-can still use PNG_DEBUG to control your own debugging:
-
-   #ifdef PNG_DEBUG
-       fprintf(stderr, ...
-   #endif
-
-When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
-having level = 0 will be printed.  There aren't any such statements in
-this version of libpng, but if you insert some they will be printed.
-
-.SH VI.  MNG support
-
-The MNG specification (available at http://www.libpng.org/pub/mng) allows
-certain extensions to PNG for PNG images that are embedded in MNG datastreams.
-Libpng can support some of these extensions.  To enable them, use the
-png_permit_mng_features() function:
-
-   feature_set = png_permit_mng_features(png_ptr, mask)
-
-   mask is a png_uint_32 containing the bitwise OR of the
-        features you want to enable.  These include
-        PNG_FLAG_MNG_EMPTY_PLTE
-        PNG_FLAG_MNG_FILTER_64
-        PNG_ALL_MNG_FEATURES
-
-   feature_set is a png_uint_32 that is the bitwise AND of
-      your mask with the set of MNG features that is
-      supported by the version of libpng that you are using.
-
-It is an error to use this function when reading or writing a standalone
-PNG file with the PNG 8-byte signature.  The PNG datastream must be wrapped
-in a MNG datastream.  As a minimum, it must have the MNG 8-byte signature
-and the MHDR and MEND chunks.  Libpng does not provide support for these
-or any other MNG chunks; your application must provide its own support for
-them.  You may wish to consider using libmng (available at
-http://www.libmng.com) instead.
-
-.SH VII.  Changes to Libpng from version 0.88
-
-It should be noted that versions of libpng later than 0.96 are not
-distributed by the original libpng author, Guy Schalnat, nor by
-Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
-distributed versions 0.89 through 0.96, but rather by another member
-of the original PNG Group, Glenn Randers-Pehrson.  Guy and Andreas are
-still alive and well, but they have moved on to other things.
-
-The old libpng functions png_read_init(), png_write_init(),
-png_info_init(), png_read_destroy(), and png_write_destroy() have been
-moved to PNG_INTERNAL in version 0.95 to discourage their use.  These
-functions will be removed from libpng version 1.4.0.
-
-The preferred method of creating and initializing the libpng structures is
-via the png_create_read_struct(), png_create_write_struct(), and
-png_create_info_struct() because they isolate the size of the structures
-from the application, allow version error checking, and also allow the
-use of custom error handling routines during the initialization, which
-the old functions do not.  The functions png_read_destroy() and
-png_write_destroy() do not actually free the memory that libpng
-allocated for these structs, but just reset the data structures, so they
-can be used instead of png_destroy_read_struct() and
-png_destroy_write_struct() if you feel there is too much system overhead
-allocating and freeing the png_struct for each image read.
-
-Setting the error callbacks via png_set_message_fn() before
-png_read_init() as was suggested in libpng-0.88 is no longer supported
-because this caused applications that do not use custom error functions
-to fail if the png_ptr was not initialized to zero.  It is still possible
-to set the error callbacks AFTER png_read_init(), or to change them with
-png_set_error_fn(), which is essentially the same function, but with a new
-name to force compilation errors with applications that try to use the old
-method.
-
-Starting with version 1.0.7, you can find out which version of the library
-you are using at run-time:
-
-   png_uint_32 libpng_vn = png_access_version_number();
-
-The number libpng_vn is constructed from the major version, minor
-version with leading zero, and release number with leading zero,
-(e.g., libpng_vn for version 1.0.7 is 10007).
-
-Note that this function does not take a png_ptr, so you can call it
-before you've created one.
-
-You can also check which version of png.h you used when compiling your
-application:
-
-   png_uint_32 application_vn = PNG_LIBPNG_VER;
-
-.SH VIII.  Changes to Libpng from version 1.0.x to 1.2.x
-
-Support for user memory management was enabled by default.  To
-accomplish this, the functions png_create_read_struct_2(),
-png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
-png_malloc_default(), and png_free_default() were added.
-
-Support for the iTXt chunk has been enabled by default as of
-version 1.2.41.
-
-Support for certain MNG features was enabled.
-
-Support for numbered error messages was added.  However, we never got
-around to actually numbering the error messages.  The function
-png_set_strip_error_numbers() was added (Note: the prototype for this
-function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
-builds of libpng-1.2.15.  It was restored in libpng-1.2.36).
-
-The png_malloc_warn() function was added at libpng-1.2.3.  This issues
-a png_warning and returns NULL instead of aborting when it fails to
-acquire the requested memory allocation.
-
-Support for setting user limits on image width and height was enabled
-by default.  The functions png_set_user_limits(), png_get_user_width_max(),
-and png_get_user_height_max() were added at libpng-1.2.6.
-
-The png_set_add_alpha() function was added at libpng-1.2.7.
-
-The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
-Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
-tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
-deprecated.
-
-A number of macro definitions in support of runtime selection of
-assembler code features (especially Intel MMX code support) were
-added at libpng-1.2.0:
-
-    PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
-    PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
-    PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
-    PNG_ASM_FLAG_MMX_READ_INTERLACE
-    PNG_ASM_FLAG_MMX_READ_FILTER_SUB
-    PNG_ASM_FLAG_MMX_READ_FILTER_UP
-    PNG_ASM_FLAG_MMX_READ_FILTER_AVG
-    PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
-    PNG_ASM_FLAGS_INITIALIZED
-    PNG_MMX_READ_FLAGS
-    PNG_MMX_FLAGS
-    PNG_MMX_WRITE_FLAGS
-    PNG_MMX_FLAGS
-
-We added the following functions in support of runtime
-selection of assembler code features:
-
-    png_get_mmx_flagmask()
-    png_set_mmx_thresholds()
-    png_get_asm_flags()
-    png_get_mmx_bitdepth_threshold()
-    png_get_mmx_rowbytes_threshold()
-    png_set_asm_flags()
-
-We replaced all of these functions with simple stubs in libpng-1.2.20,
-when the Intel assembler code was removed due to a licensing issue.
-
-These macros are deprecated:
-
-    PNG_READ_TRANSFORMS_NOT_SUPPORTED
-    PNG_PROGRESSIVE_READ_NOT_SUPPORTED
-    PNG_NO_SEQUENTIAL_READ_SUPPORTED
-    PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
-    PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
-    PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
-
-They have been replaced, respectively, by:
-
-    PNG_NO_READ_TRANSFORMS
-    PNG_NO_PROGRESSIVE_READ
-    PNG_NO_SEQUENTIAL_READ
-    PNG_NO_WRITE_TRANSFORMS
-    PNG_NO_READ_ANCILLARY_CHUNKS
-    PNG_NO_WRITE_ANCILLARY_CHUNKS
-
-PNG_MAX_UINT was replaced with PNG_UINT_31_MAX.  It has been
-deprecated since libpng-1.0.16 and libpng-1.2.6.
-
-The function
-    png_check_sig(sig, num)
-was replaced with
-    !png_sig_cmp(sig, 0, num)
-It has been deprecated since libpng-0.90.
-
-The function
-    png_set_gray_1_2_4_to_8()
-which also expands tRNS to alpha was replaced with
-    png_set_expand_gray_1_2_4_to_8()
-which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
-
-.SH IX.  Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
-
-Private libpng prototypes and macro definitions were moved from
-png.h and pngconf.h into a new pngpriv.h header file.
-
-Functions png_set_benign_errors(), png_benign_error(), and
-png_chunk_benign_error() were added.
-
-Support for setting the maximum amount of memory that the application
-will allocate for reading chunks was added, as a security measure.
-The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
-were added to the library.
-
-We implemented support for I/O states by adding png_ptr member io_state
-and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
-
-We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
-input transforms.
-
-Checking for and reporting of errors in the IHDR chunk is more thorough.
-
-Support for global arrays was removed, to improve thread safety.
-
-Some obsolete/deprecated macros and functions have been removed.
-
-Typecasted NULL definitions such as
-   #define png_voidp_NULL            (png_voidp)NULL
-were eliminated.  If you used these in your application, just use
-NULL instead.
-
-The png_struct and info_struct members "trans" and "trans_values" were
-changed to "trans_alpha" and "trans_color", respectively.
-
-The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
-were removed.
-
-The PNG_1_0_X and PNG_1_2_X macros were eliminated.
-
-The PNG_LEGACY_SUPPORTED macro was eliminated.
-
-Many WIN32_WCE #ifdefs were removed.
-
-The functions png_read_init(info_ptr), png_write_init(info_ptr),
-png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
-have been removed.  They have been deprecated since libpng-0.95.
-
-The png_permit_empty_plte() was removed. It has been deprecated
-since libpng-1.0.9.  Use png_permit_mng_features() instead.
-
-We removed the obsolete stub functions png_get_mmx_flagmask(),
-png_set_mmx_thresholds(), png_get_asm_flags(),
-png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
-png_set_asm_flags(), and png_mmx_supported()
-
-We removed the obsolete png_check_sig(), png_memcpy_check(), and
-png_memset_check() functions.  Instead use !png_sig_cmp(), memcpy(),
-and memset(), respectively.
-
-The function png_set_gray_1_2_4_to_8() was removed. It has been
-deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
-png_set_expand_gray_1_2_4_to_8() because the former function also
-expanded any tRNS chunk to an alpha channel.
-
-Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32
-were added and are used by default instead of the corresponding
-functions. Unfortunately,
-from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
-function) incorrectly returned a value of type png_uint_32.
-
-We changed the prototype for png_malloc() from
-    png_malloc(png_structp png_ptr, png_uint_32 size)
-to
-    png_malloc(png_structp png_ptr, png_alloc_size_t size)
-
-This also applies to the prototype for the user replacement malloc_fn().
-
-The png_calloc() function was added and is used in place of
-of "png_malloc(); memset();" except in the case in png_read_png()
-where the array consists of pointers; in this case a "for" loop is used
-after the png_malloc() to set the pointers to NULL, to give robust.
-behavior in case the application runs out of memory part-way through
-the process.
-
-We changed the prototypes of png_get_compression_buffer_size() and
-png_set_compression_buffer_size() to work with png_size_t instead of
-png_uint_32.
-
-Support for numbered error messages was removed by default, since we
-never got around to actually numbering the error messages. The function
-png_set_strip_error_numbers() was removed from the library by default.
-
-The png_zalloc() and png_zfree() functions are no longer exported.
-The png_zalloc() function no longer zeroes out the memory that it
-allocates.
-
-Support for dithering was disabled by default in libpng-1.4.0, because
-it has not been well tested and doesn't actually "dither".
-The code was not
-removed, however, and could be enabled by building libpng with
-PNG_READ_DITHER_SUPPORTED defined.  In libpng-1.4.2, this support
-was reenabled, but the function was renamed png_set_quantize() to
-reflect more accurately what it actually does.  At the same time,
-the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
-PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED
-was renamed to PNG_READ_QUANTIZE_SUPPORTED.
-
-We removed the trailing '.' from the warning and error messages.
-
-.SH X.  Changes to Libpng from version 1.4.x to 1.5.x
-
-From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
-function) incorrectly returned a value of type png_uint_32.
-
-Checking for invalid palette index on read or write was added at libpng
-1.5.10.  When an invalid index is found, libpng issues a benign error.
-This is enabled by default but can be disabled in each png_ptr with
-
-   png_set_check_for_invalid_index(png_ptr, allowed);
-
-      allowed  - one of
-                 0: disable
-                 1: enable
-
-A. Changes that affect users of libpng
-
-There are no substantial API changes between the non-deprecated parts of
-the 1.4.5 API and the 1.5.0 API, however the ability to directly access
-the main libpng control structures, png_struct and png_info, deprecated
-in earlier versions of libpng, has been completely removed from
-libpng 1.5.
-
-We no longer include zlib.h in png.h.  Applications that need access
-to information in zlib.h will need to add the '#include "zlib.h"'
-directive.  It does not matter whether it is placed prior to or after
-the '"#include png.h"' directive.
-
-We moved the png_strcpy(), png_strncpy(), png_strlen(), png_memcpy(),
-png_memcmp(), png_sprintf, and png_memcpy() macros into a private
-header file (pngpriv.h) that is not accessible to applications.
-
-In png_get_iCCP, the type of "profile" was changed from png_charpp
-to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep.
-
-There are changes of form in png.h, including new and changed macros to
-declare parts of the API.  Some API functions with arguments that are
-pointers to data not modified within the function have been corrected to
-declare these arguments with PNG_CONST.
-
-Much of the internal use of C macros to control the library build has also
-changed and some of this is visible in the exported header files, in
-particular the use of macros to control data and API elements visible
-during application compilation may require significant revision to
-application code.  (It is extremely rare for an application to do this.)
-
-Any program that compiled against libpng 1.4 and did not use deprecated
-features or access internal library structures should compile and work
-against libpng 1.5, except for the change in the prototype for
-png_get_iCCP() and png_set_iCCP() API functions mentioned above.
-
-libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of
-interlaced images.  The macros return the number of rows and columns in
-each pass and information that can be used to de-interlace and (if
-absolutely necessary) interlace an image.
-
-libpng 1.5.0 adds an API png_longjmp(png_ptr, value).  This API calls
-the application-provided png_longjmp_ptr on the internal, but application
-initialized, longjmp buffer.  It is provided as a convenience to avoid
-the need to use the png_jmpbuf macro, which had the unnecessary side
-effect of resetting the internal png_longjmp_ptr value.
-
-libpng 1.5.0 includes a complete fixed point API.  By default this is
-present along with the corresponding floating point API.  In general the
-fixed point API is faster and smaller than the floating point one because
-the PNG file format used fixed point, not floating point.  This applies
-even if the library uses floating point in internal calculations.  A new
-macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library
-uses floating point arithmetic (the default) or fixed point arithmetic
-internally for performance critical calculations such as gamma correction.
-In some cases, the gamma calculations may produce slightly different
-results.  This has changed the results in png_rgb_to_gray and in alpha
-composition (png_set_background for example). This applies even if the
-original image was already linear (gamma == 1.0) and, therefore, it is
-not necessary to linearize the image.  This is because libpng has *not*
-been changed to optimize that case correctly, yet.
-
-Fixed point support for the sCAL chunk comes with an important caveat;
-the sCAL specification uses a decimal encoding of floating point values
-and the accuracy of PNG fixed point values is insufficient for
-representation of these values. Consequently a "string" API
-(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
-arbitrary sCAL chunks in the absence of either the floating point API or
-internal floating point calculations.
-
-Applications no longer need to include the optional distribution header
-file pngusr.h or define the corresponding macros during application
-build in order to see the correct variant of the libpng API.  From 1.5.0
-application code can check for the corresponding _SUPPORTED macro:
-
-#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
-   /* code that uses the inch conversion APIs. */
-#endif
-
-This macro will only be defined if the inch conversion functions have been
-compiled into libpng.  The full set of macros, and whether or not support
-has been compiled in, are available in the header file pnglibconf.h.
-This header file is specific to the libpng build.  Notice that prior to
-1.5.0 the _SUPPORTED macros would always have the default definition unless
-reset by pngusr.h or by explicit settings on the compiler command line.
-These settings may produce compiler warnings or errors in 1.5.0 because
-of macro redefinition.
-
-From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
-function) incorrectly returned a value of type png_uint_32.  libpng 1.5.0
-is consistent with the implementation in 1.4.5 and 1.2.x (where the macro
-did not exist.)
-
-Applications can now choose whether to use these macros or to call the
-corresponding function by defining PNG_USE_READ_MACROS or
-PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
-only supported from 1.5.0 -defining PNG_NO_USE_READ_MACROS prior to 1.5.0
-will lead to a link failure.
-
-Prior to libpng-1.5.4, the zlib compressor used the same set of parameters
-when compressing the IDAT data and textual data such as zTXt and iCCP.
-In libpng-1.5.4 we reinitialized the zlib stream for each type of data.
-We added five png_set_text_*() functions for setting the parameters to
-use with textual data.
-
-Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
-option was off by default, and slightly inaccurate scaling occurred.
-This option can no longer be turned off, and the choice of accurate
-or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
-API for accurate scaling or the old png_set_strip_16_to_8() API for simple
-chopping.
-
-Prior to libpng-1.5.4, the png_set_user_limits() function could only be
-used to reduce the width and height limits from the value of
-PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
-that it could be used to override them.  Now this function will reduce or
-increase the limits.
-
-Starting in libpng-1.5.10, the user limits can be set en masse with the
-configuration option PNG_SAFE_LIMITS_SUPPORTED.  If this option is enabled,
-a set of "safe" limits is applied in pngpriv.h.  These can be overridden by
-application calls to png_set_user_limits(), png_set_user_chunk_cache_max(),
-and/or png_set_user_malloc_max() that increase or decrease the limits.  Also,
-in libpng-1.5.10 the default width and height limits were increased
-from 1,000,000 to 0x7ffffff (i.e., made unlimited).  Therefore, the
-limits are now
-                               default      safe
-   png_user_width_max        0x7fffffff    1,000,000
-   png_user_height_max       0x7fffffff    1,000,000
-   png_user_chunk_cache_max  0 (unlimited)   128
-   png_user_chunk_malloc_max 0 (unlimited) 8,000,000
-
-B. Changes to the build and configuration of libpng
-
-Details of internal changes to the library code can be found in the CHANGES
-file and in the GIT repository logs.  These will be of no concern to the vast
-majority of library users or builders, however the few who configure libpng
-to a non-default feature set may need to change how this is done.
-
-There should be no need for library builders to alter build scripts if
-these use the distributed build support - configure or the makefiles -
-however users of the makefiles may care to update their build scripts
-to build pnglibconf.h where the corresponding makefile does not do so.
-
-Building libpng with a non-default configuration has changed completely.
-The old method using pngusr.h should still work correctly even though the
-way pngusr.h is used in the build has been changed; however, library
-builders will probably want to examine the changes to take advantage of
-new capabilities and to simplify their build system.
-
-B.1 Specific changes to library configuration capabilities
-
-The library now supports a complete fixed point implementation and can
-thus be used on systems that have no floating point support or very
-limited or slow support.  Previously gamma correction, an essential part
-of complete PNG support, required reasonably fast floating point.
-
-As part of this the choice of internal implementation has been made
-independent of the choice of fixed versus floating point APIs and all the
-missing fixed point APIs have been implemented.
-
-The exact mechanism used to control attributes of API functions has
-changed.  A single set of operating system independent macro definitions
-is used and operating system specific directives are defined in
-pnglibconf.h
-
-As part of this the mechanism used to choose procedure call standards on
-those systems that allow a choice has been changed.  At present this only
-affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
-running on Intel processors.  As before, PNGAPI is defined where required
-to control the exported API functions; however, two new macros, PNGCBAPI
-and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
-(PNGCAPI) for functions that must match a C library prototype (currently
-only png_longjmp_ptr, which must match the C longjmp function.)  The new
-approach is documented in pngconf.h
-
-Despite these changes, libpng 1.5.0 only supports the native C function
-calling standard on those platforms tested so far (__cdecl on Microsoft
-Windows).  This is because the support requirements for alternative
-calling conventions seem to no longer exist.  Developers who find it
-necessary to set PNG_API_RULE to 1 should advise the mailing list
-(png-mng-implement) of this and library builders who use Openwatcom and
-therefore set PNG_API_RULE to 2 should also contact the mailing list.
-
-A new test program, pngvalid, is provided in addition to pngtest.
-pngvalid validates the arithmetic accuracy of the gamma correction
-calculations and includes a number of validations of the file format.
-A subset of the full range of tests is run when "make check" is done
-(in the 'configure' build.)  pngvalid also allows total allocated memory
-usage to be evaluated and performs additional memory overwrite validation.
-
-Many changes to individual feature macros have been made. The following
-are the changes most likely to be noticed by library builders who
-configure libpng:
-
-1) All feature macros now have consistent naming:
-
-#define PNG_NO_feature turns the feature off
-#define PNG_feature_SUPPORTED turns the feature on
-
-pnglibconf.h contains one line for each feature macro which is either:
-
-#define PNG_feature_SUPPORTED
-
-if the feature is supported or:
-
-/*#undef PNG_feature_SUPPORTED*/
-
-if it is not.  Library code consistently checks for the 'SUPPORTED' macro.
-It does not, and libpng applications should not, check for the 'NO' macro
-which will not normally be defined even if the feature is not supported.
-The 'NO' macros are only used internally for setting or not setting the
-corresponding 'SUPPORTED' macros.
-
-Compatibility with the old names is provided as follows:
-
-PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED
-
-And the following definitions disable the corresponding feature:
-
-PNG_SETJMP_NOT_SUPPORTED disables SETJMP
-PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS
-PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV
-PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS
-PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS
-PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS
-
-Library builders should remove use of the above, inconsistent, names.
-
-2) Warning and error message formatting was previously conditional on
-the STDIO feature. The library has been changed to use the
-CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled
-the library no longer uses the printf(3) functions, even though the
-default read/write implementations use (FILE) style stdio.h functions.
-
-3) Three feature macros now control the fixed/floating point decisions:
-
-PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs
-
-PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in
-practice these are normally required internally anyway (because the PNG
-file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT
-merely stops the function from being exported.
-
-PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating
-point implementation or the fixed point one.  Typically the fixed point
-implementation is larger and slower than the floating point implementation
-on a system that supports floating point, however it may be faster on a
-system which lacks floating point hardware and therefore uses a software
-emulation.
-
-4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the
-functions to read and write ints to be disabled independently of
-PNG_USE_READ_MACROS, which allows libpng to be built with the functions
-even though the default is to use the macros - this allows applications
-to choose at app buildtime whether or not to use macros (previously
-impossible because the functions weren't in the default build.)
-
-B.2 Changes to the configuration mechanism
-
-Prior to libpng-1.5.0 library builders who needed to configure libpng
-had either to modify the exported pngconf.h header file to add system
-specific configuration or had to write feature selection macros into
-pngusr.h and cause this to be included into pngconf.h by defining
-PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
-application built without PNG_USER_CONFIG defined would see the
-unmodified, default, libpng API and thus would probably fail to link.
-
-These mechanisms still work in the configure build and in any makefile
-build that builds pnglibconf.h, although the feature selection macros
-have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
-processed only once, when the exported header file pnglibconf.h is built.
-pngconf.h no longer includes pngusr.h, therefore pngusr.h is ignored after the
-build of pnglibconf.h and it is never included in an application build.
-
-The rarely used alternative of adding a list of feature macros to the
-CFLAGS setting in the build also still works, however the macros will be
-copied to pnglibconf.h and this may produce macro redefinition warnings
-when the individual C files are compiled.
-
-All configuration now only works if pnglibconf.h is built from
-scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
-(the original author of awk) maintains C source code of that awk and this
-and all known later implementations (often called by subtly different
-names - nawk and gawk for example) are adequate to build pnglibconf.h.
-The Sun Microsystems (now Oracle) program 'awk' is an earlier version
-and does not work; this may also apply to other systems that have a
-functioning awk called 'nawk'.
-
-Configuration options are now documented in scripts/pnglibconf.dfa.  This
-file also includes dependency information that ensures a configuration is
-consistent; that is, if a feature is switched off dependent features are
-also removed.  As a recommended alternative to using feature macros in
-pngusr.h a system builder may also define equivalent options in pngusr.dfa
-(or, indeed, any file) and add that to the configuration by setting
-DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
-how to do this, and a case where pngusr.h is still required.
-
-.SH XI. Detecting libpng
-
-The png_get_io_ptr() function has been present since libpng-0.88, has never
-changed, and is unaffected by conditional compilation macros.  It is the
-best choice for use in configure scripts for detecting the presence of any
-libpng version since 0.88.  In an autoconf "configure.in" you could use
-
-    AC_CHECK_LIB(png, png_get_io_ptr, ...
-
-.SH XII. Source code repository
-
-Since about February 2009, version 1.2.34, libpng has been under "git" source
-control.  The git repository was built from old libpng-x.y.z.tar.gz files
-going back to version 0.70.  You can access the git repository (read only)
-at
-
-    git://libpng.git.sourceforge.net/gitroot/libpng
-
-or you can browse it via "gitweb" at
-
-    http://libpng.git.sourceforge.net/git/gitweb.cgi?p=libpng
-
-Patches can be sent to glennrp at users.sourceforge.net or to
-png-mng-implement at lists.sourceforge.net or you can upload them to
-the libpng bug tracker at
-
-    http://libpng.sourceforge.net
-
-We also accept patches built from the tar or zip distributions, and
-simple verbal discriptions of bug fixes, reported either to the
-SourceForge bug tracker, to the png-mng-implement at lists.sf.net
-mailing list, or directly to glennrp.
-
-.SH XIII. Coding style
-
-Our coding style is similar to the "Allman" style, with curly
-braces on separate lines:
-
-    if (condition)
-    {
-       action;
-    }
-
-    else if (another condition)
-    {
-       another action;
-    }
-
-The braces can be omitted from simple one-line actions:
-
-    if (condition)
-       return (0);
-
-We use 3-space indentation, except for continued statements which
-are usually indented the same as the first line of the statement
-plus four more spaces.
-
-For macro definitions we use 2-space indentation, always leaving the "#"
-in the first column.
-
-    #ifndef PNG_NO_FEATURE
-    #  ifndef PNG_FEATURE_SUPPORTED
-    #    define PNG_FEATURE_SUPPORTED
-    #  endif
-    #endif
-
-Comments appear with the leading "/*" at the same indentation as
-the statement that follows the comment:
-
-    /* Single-line comment */
-    statement;
-
-    /* This is a multiple-line
-     * comment.
-     */
-    statement;
-
-Very short comments can be placed after the end of the statement
-to which they pertain:
-
-    statement;    /* comment */
-
-We don't use C++ style ("//") comments. We have, however,
-used them in the past in some now-abandoned MMX assembler
-code.
-
-Functions and their curly braces are not indented, and
-exported functions are marked with PNGAPI:
-
- /* This is a public function that is visible to
-  * application programmers. It does thus-and-so.
-  */
- void PNGAPI
- png_exported_function(png_ptr, png_info, foo)
- {
-    body;
- }
-
-The prototypes for all exported functions appear in png.h,
-above the comment that says
-
-    /* Maintainer: Put new public prototypes here ... */
-
-We mark all non-exported functions with "/* PRIVATE */"":
-
- void /* PRIVATE */
- png_non_exported_function(png_ptr, png_info, foo)
- {
-    body;
- }
-
-The prototypes for non-exported functions (except for those in
-pngtest) appear in
-pngpriv.h
-above the comment that says
-
-  /* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
-
-To avoid polluting the global namespace, the names of all exported
-functions and variables begin with "png_", and all publicly visible C
-preprocessor macros begin with "PNG".  We request that applications that
-use libpng *not* begin any of their own symbols with either of these strings.
-
-We put a space after each comma and after each semicolon
-in "for" statements, and we put spaces before and after each
-C binary operator and after "for" or "while", and before
-"?".  We don't put a space between a typecast and the expression
-being cast, nor do we put one between a function name and the
-left parenthesis that follows it:
-
-    for (i = 2; i > 0; --i)
-       y[i] = a(x) + (int)b;
-
-We prefer #ifdef and #ifndef to #if defined() and if !defined()
-when there is only one macro being tested.
-
-We prefer to express integers that are used as bit masks in hex format,
-with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100).
-
-We do not use the TAB character for indentation in the C sources.
-
-Lines do not exceed 80 characters.
-
-Other rules can be inferred by inspecting the libpng source.
-
-.SH XIV. Y2K Compliance in libpng
-
-March 29, 2012
-
-Since the PNG Development group is an ad-hoc body, we can't make
-an official declaration.
-
-This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.5.10 are Y2K compliant.  It is my belief that earlier
-versions were also Y2K compliant.
-
-Libpng only has three year fields.  One is a 2-byte unsigned integer that
-will hold years up to 65535.  The other two hold the date in text
-format, and will hold years up to 9999.
-
-The integer is
-    "png_uint_16 year" in png_time_struct.
-
-The strings are
-    "png_charp time_buffer" in png_struct and
-    "near_time_buffer", which is a local character string in png.c.
-
-There are seven time-related functions:
-
-    png_convert_to_rfc_1123() in png.c
-      (formerly png_convert_to_rfc_1152() in error)
-    png_convert_from_struct_tm() in pngwrite.c, called
-      in pngwrite.c
-    png_convert_from_time_t() in pngwrite.c
-    png_get_tIME() in pngget.c
-    png_handle_tIME() in pngrutil.c, called in pngread.c
-    png_set_tIME() in pngset.c
-    png_write_tIME() in pngwutil.c, called in pngwrite.c
-
-All appear to handle dates properly in a Y2K environment.  The
-png_convert_from_time_t() function calls gmtime() to convert from system
-clock time, which returns (year - 1900), which we properly convert to
-the full 4-digit year.  There is a possibility that applications using
-libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
-function, or that they are incorrectly passing only a 2-digit year
-instead of "year - 1900" into the png_convert_from_struct_tm() function,
-but this is not under our control.  The libpng documentation has always
-stated that it works with 4-digit years, and the APIs have been
-documented as such.
-
-The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
-integer to hold the year, and can hold years as large as 65535.
-
-zlib, upon which libpng depends, is also Y2K compliant.  It contains
-no date-related code.
-
-
-   Glenn Randers-Pehrson
-   libpng maintainer
-   PNG Development Group
-
-.SH NOTE
-
-Note about libpng version numbers:
-
-Due to various miscommunications, unforeseen code incompatibilities
-and occasional factors outside the authors' control, version numbering
-on the library has not always been consistent and straightforward.
-The following table summarizes matters since version 0.89c, which was
-the first widely used release:
-
- source             png.h  png.h  shared-lib
- version            string   int  version
- -------            ------  ----- ----------
- 0.89c ("beta 3")  0.89       89  1.0.89
- 0.90  ("beta 4")  0.90       90  0.90
- 0.95  ("beta 5")  0.95       95  0.95
- 0.96  ("beta 6")  0.96       96  0.96
- 0.97b ("beta 7")  1.00.97    97  1.0.1
- 0.97c             0.97       97  2.0.97
- 0.98              0.98       98  2.0.98
- 0.99              0.99       98  2.0.99
- 0.99a-m           0.99       99  2.0.99
- 1.00              1.00      100  2.1.0
- 1.0.0             1.0.0     100  2.1.0
- 1.0.0   (from here on, the  100  2.1.0
- 1.0.1    png.h string is  10001  2.1.0
- 1.0.1a-e identical to the 10002  from here on, the
- 1.0.2    source version)  10002  shared library is 2.V
- 1.0.2a-b                  10003  where V is the source
- 1.0.1                     10001  code version except as
- 1.0.1a-e                  10002  2.1.0.1a-e   noted.
- 1.0.2                     10002  2.1.0.2
- 1.0.2a-b                  10003  2.1.0.2a-b
- 1.0.3                     10003  2.1.0.3
- 1.0.3a-d                  10004  2.1.0.3a-d
- 1.0.4                     10004  2.1.0.4
- 1.0.4a-f                  10005  2.1.0.4a-f
- 1.0.5 (+ 2 patches)       10005  2.1.0.5
- 1.0.5a-d                  10006  2.1.0.5a-d
- 1.0.5e-r                  10100  2.1.0.5e-r
- 1.0.5s-v                  10006  2.1.0.5s-v
- 1.0.6 (+ 3 patches)       10006  2.1.0.6
- 1.0.6d-g                  10007  2.1.0.6d-g
- 1.0.6h                    10007  10.6h
- 1.0.6i                    10007  10.6i
- 1.0.6j                    10007  2.1.0.6j
- 1.0.7beta11-14    DLLNUM  10007  2.1.0.7beta11-14
- 1.0.7beta15-18       1    10007  2.1.0.7beta15-18
- 1.0.7rc1-2           1    10007  2.1.0.7rc1-2
- 1.0.7                1    10007  2.1.0.7
- 1.0.8beta1-4         1    10008  2.1.0.8beta1-4
- 1.0.8rc1             1    10008  2.1.0.8rc1
- 1.0.8                1    10008  2.1.0.8
- 1.0.9beta1-6         1    10009  2.1.0.9beta1-6
- 1.0.9rc1             1    10009  2.1.0.9rc1
- 1.0.9beta7-10        1    10009  2.1.0.9beta7-10
- 1.0.9rc2             1    10009  2.1.0.9rc2
- 1.0.9                1    10009  2.1.0.9
- 1.0.10beta1          1    10010  2.1.0.10beta1
- 1.0.10rc1            1    10010  2.1.0.10rc1
- 1.0.10               1    10010  2.1.0.10
- 1.0.11beta1-3        1    10011  2.1.0.11beta1-3
- 1.0.11rc1            1    10011  2.1.0.11rc1
- 1.0.11               1    10011  2.1.0.11
- 1.0.12beta1-2        2    10012  2.1.0.12beta1-2
- 1.0.12rc1            2    10012  2.1.0.12rc1
- 1.0.12               2    10012  2.1.0.12
- 1.1.0a-f             -    10100  2.1.1.0a-f abandoned
- 1.2.0beta1-2         2    10200  2.1.2.0beta1-2
- 1.2.0beta3-5         3    10200  3.1.2.0beta3-5
- 1.2.0rc1             3    10200  3.1.2.0rc1
- 1.2.0                3    10200  3.1.2.0
- 1.2.1beta-4          3    10201  3.1.2.1beta1-4
- 1.2.1rc1-2           3    10201  3.1.2.1rc1-2
- 1.2.1                3    10201  3.1.2.1
- 1.2.2beta1-6        12    10202  12.so.0.1.2.2beta1-6
- 1.0.13beta1         10    10013  10.so.0.1.0.13beta1
- 1.0.13rc1           10    10013  10.so.0.1.0.13rc1
- 1.2.2rc1            12    10202  12.so.0.1.2.2rc1
- 1.0.13              10    10013  10.so.0.1.0.13
- 1.2.2               12    10202  12.so.0.1.2.2
- 1.2.3rc1-6          12    10203  12.so.0.1.2.3rc1-6
- 1.2.3               12    10203  12.so.0.1.2.3
- 1.2.4beta1-3        13    10204  12.so.0.1.2.4beta1-3
- 1.2.4rc1            13    10204  12.so.0.1.2.4rc1
- 1.0.14              10    10014  10.so.0.1.0.14
- 1.2.4               13    10204  12.so.0.1.2.4
- 1.2.5beta1-2        13    10205  12.so.0.1.2.5beta1-2
- 1.0.15rc1           10    10015  10.so.0.1.0.15rc1
- 1.0.15              10    10015  10.so.0.1.0.15
- 1.2.5               13    10205  12.so.0.1.2.5
- 1.2.6beta1-4        13    10206  12.so.0.1.2.6beta1-4
- 1.2.6rc1-5          13    10206  12.so.0.1.2.6rc1-5
- 1.0.16              10    10016  10.so.0.1.0.16
- 1.2.6               13    10206  12.so.0.1.2.6
- 1.2.7beta1-2        13    10207  12.so.0.1.2.7beta1-2
- 1.0.17rc1           10    10017  12.so.0.1.0.17rc1
- 1.2.7rc1            13    10207  12.so.0.1.2.7rc1
- 1.0.17              10    10017  12.so.0.1.0.17
- 1.2.7               13    10207  12.so.0.1.2.7
- 1.2.8beta1-5        13    10208  12.so.0.1.2.8beta1-5
- 1.0.18rc1-5         10    10018  12.so.0.1.0.18rc1-5
- 1.2.8rc1-5          13    10208  12.so.0.1.2.8rc1-5
- 1.0.18              10    10018  12.so.0.1.0.18
- 1.2.8               13    10208  12.so.0.1.2.8
- 1.2.9beta1-3        13    10209  12.so.0.1.2.9beta1-3
- 1.2.9beta4-11       13    10209  12.so.0.9[.0]
- 1.2.9rc1            13    10209  12.so.0.9[.0]
- 1.2.9               13    10209  12.so.0.9[.0]
- 1.2.10beta1-7       13    10210  12.so.0.10[.0]
- 1.2.10rc1-2         13    10210  12.so.0.10[.0]
- 1.2.10              13    10210  12.so.0.10[.0]
- 1.4.0beta1-6        14    10400  14.so.0.0[.0]
- 1.2.11beta1-4       13    10210  12.so.0.11[.0]
- 1.4.0beta7-8        14    10400  14.so.0.0[.0]
- 1.2.11              13    10211  12.so.0.11[.0]
- 1.2.12              13    10212  12.so.0.12[.0]
- 1.4.0beta9-14       14    10400  14.so.0.0[.0]
- 1.2.13              13    10213  12.so.0.13[.0]
- 1.4.0beta15-36      14    10400  14.so.0.0[.0]
- 1.4.0beta37-87      14    10400  14.so.14.0[.0]
- 1.4.0rc01           14    10400  14.so.14.0[.0]
- 1.4.0beta88-109     14    10400  14.so.14.0[.0]
- 1.4.0rc02-08        14    10400  14.so.14.0[.0]
- 1.4.0               14    10400  14.so.14.0[.0]
- 1.4.1beta01-03      14    10401  14.so.14.1[.0]
- 1.4.1rc01           14    10401  14.so.14.1[.0]
- 1.4.1beta04-12      14    10401  14.so.14.1[.0]
- 1.4.1               14    10401  14.so.14.1[.0]
- 1.4.2               14    10402  14.so.14.2[.0]
- 1.4.3               14    10403  14.so.14.3[.0]
- 1.4.4               14    10404  14.so.14.4[.0]
- 1.5.0beta01-58      15    10500  15.so.15.0[.0]
- 1.5.0rc01-07        15    10500  15.so.15.0[.0]
- 1.5.0               15    10500  15.so.15.0[.0]
- 1.5.1beta01-11      15    10501  15.so.15.1[.0]
- 1.5.1rc01-02        15    10501  15.so.15.1[.0]
- 1.5.1               15    10501  15.so.15.1[.0]
- 1.5.2beta01-03      15    10502  15.so.15.2[.0]
- 1.5.2rc01-03        15    10502  15.so.15.2[.0]
- 1.5.2               15    10502  15.so.15.2[.0]
- 1.5.3beta01-10      15    10503  15.so.15.3[.0]
- 1.5.3rc01-02        15    10503  15.so.15.3[.0]
- 1.5.3beta11         15    10503  15.so.15.3[.0]
- 1.5.3 [omitted]
- 1.5.4beta01-08      15    10504  15.so.15.4[.0]
- 1.5.4rc01           15    10504  15.so.15.4[.0]
- 1.5.4               15    10504  15.so.15.4[.0]
- 1.5.5beta01-08      15    10505  15.so.15.5[.0]
- 1.5.5rc01           15    10505  15.so.15.5[.0]
- 1.5.5               15    10505  15.so.15.5[.0]
- 1.5.6beta01-07      15    10506  15.so.15.6[.0]
- 1.5.6rc01-03        15    10506  15.so.15.6[.0]
- 1.5.6               15    10506  15.so.15.6[.0]
- 1.5.7beta01-05      15    10507  15.so.15.7[.0]
- 1.5.7rc01-03        15    10507  15.so.15.7[.0]
- 1.5.7               15    10507  15.so.15.7[.0]
- 1.5.8beta01         15    10508  15.so.15.8[.0]
- 1.5.8rc01           15    10508  15.so.15.8[.0]
- 1.5.8               15    10508  15.so.15.8[.0]
- 1.5.9beta01-02      15    10509  15.so.15.9[.0]
- 1.5.9rc01           15    10509  15.so.15.9[.0]
- 1.5.9               15    10509  15.so.15.9[.0]
- 1.5.10beta01-05     15    10510  15.so.15.10[.0]
- 1.5.10              15    10510  15.so.15.10[.0]
-
-Henceforth the source version will match the shared-library minor
-and patch numbers; the shared-library major version number will be
-used for changes in backward compatibility, as it is intended.  The
-PNG_PNGLIB_VER macro, which is not used within libpng but is available
-for applications, is an unsigned integer of the form xyyzz corresponding
-to the source version x.y.z (leading zeros in y and z).  Beta versions
-were given the previous public release number plus a letter, until
-version 1.0.6j; from then on they were given the upcoming public
-release number plus "betaNN" or "rcN".
-
-.SH "SEE ALSO"
-.BR "png"(5), " libpngpf"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
-
-.LP
-.IR libpng :
-.IP
-http://libpng.sourceforge.net (follow the [DOWNLOAD] link)
-http://www.libpng.org/pub/png
-
-.LP
-.IR zlib :
-.IP
-(generally) at the same location as
-.I libpng
-or at
-.br
-ftp://ftp.info-zip.org/pub/infozip/zlib
-
-.LP
-.IR PNG specification: RFC 2083
-.IP
-(generally) at the same location as
-.I libpng
-or at
-.br
-ftp://ds.internic.net/rfc/rfc2083.txt
-.br
-or (as a W3C Recommendation) at
-.br
-http://www.w3.org/TR/REC-png.html
-
-.LP
-In the case of any inconsistency between the PNG specification
-and this library, the specification takes precedence.
-
-.SH AUTHORS
-This man page: Glenn Randers-Pehrson
-<glennrp at users.sourceforge.net>
-
-The contributing authors would like to thank all those who helped
-with testing, bug fixes, and patience.  This wouldn't have been
-possible without all of you.
-
-Thanks to Frank J. T. Wojcik for helping with the documentation.
-
-Libpng version 1.5.10 - March 29, 2012:
-Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
-Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
-
-Supported by the PNG development group
-.br
-png-mng-implement at lists.sf.net
-(subscription required; visit
-png-mng-implement at lists.sourceforge.net (subscription required; visit
-https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe).
-
-.SH COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
-
-(This copy of the libpng notices is provided for your convenience.  In case of
-any discrepancy between this copy and the notices in the file png.h that is
-included in the libpng distribution, the latter shall prevail.)
-
-If you modify libpng you may insert additional notices immediately following
-this sentence.
-
-This code is released under the libpng license.
-
-libpng versions 1.2.6, August 15, 2004, through 1.5.10, March 29, 2012, are
-Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
-distributed according to the same disclaimer and license as libpng-1.2.5
-with the following individual added to the list of Contributing Authors
-
-   Cosmin Truta
-
-libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
-Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
-distributed according to the same disclaimer and license as libpng-1.0.6
-with the following individuals added to the list of Contributing Authors
-
-   Simon-Pierre Cadieux
-   Eric S. Raymond
-   Gilles Vollant
-
-and with the following additions to the disclaimer:
-
-   There is no warranty against interference with your
-   enjoyment of the library or against infringement.
-   There is no warranty that our efforts or the library
-   will fulfill any of your particular purposes or needs.
-   This library is provided with all faults, and the entire
-   risk of satisfactory quality, performance, accuracy, and
-   effort is with the user.
-
-libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
-Copyright (c) 1998, 1999 Glenn Randers-Pehrson
-Distributed according to the same disclaimer and license as libpng-0.96,
-with the following individuals added to the list of Contributing Authors:
-
-   Tom Lane
-   Glenn Randers-Pehrson
-   Willem van Schaik
-
-libpng versions 0.89, June 1996, through 0.96, May 1997, are
-Copyright (c) 1996, 1997 Andreas Dilger
-Distributed according to the same disclaimer and license as libpng-0.88,
-with the following individuals added to the list of Contributing Authors:
-
-   John Bowler
-   Kevin Bracey
-   Sam Bushell
-   Magnus Holmgren
-   Greg Roelofs
-   Tom Tanner
-
-libpng versions 0.5, May 1995, through 0.88, January 1996, are
-Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-
-For the purposes of this copyright and license, "Contributing Authors"
-is defined as the following set of individuals:
-
-   Andreas Dilger
-   Dave Martindale
-   Guy Eric Schalnat
-   Paul Schmidt
-   Tim Wegner
-
-The PNG Reference Library is supplied "AS IS".  The Contributing Authors
-and Group 42, Inc. disclaim all warranties, expressed or implied,
-including, without limitation, the warranties of merchantability and of
-fitness for any purpose.  The Contributing Authors and Group 42, Inc.
-assume no liability for direct, indirect, incidental, special, exemplary,
-or consequential damages, which may result from the use of the PNG
-Reference Library, even if advised of the possibility of such damage.
-
-Permission is hereby granted to use, copy, modify, and distribute this
-source code, or portions hereof, for any purpose, without fee, subject
-to the following restrictions:
-
-1. The origin of this source code must not be misrepresented.
-
-2. Altered versions must be plainly marked as such and
-   must not be misrepresented as being the original source.
-
-3. This Copyright notice may not be removed or altered from
-   any source or altered source distribution.
-
-The Contributing Authors and Group 42, Inc. specifically permit, without
-fee, and encourage the use of this source code as a component to
-supporting the PNG file format in commercial products.  If you use this
-source code in a product, acknowledgment is not required but would be
-appreciated.
-
-
-A "png_get_copyright" function is available, for convenient use in "about"
-boxes and the like:
-
-   printf("%s",png_get_copyright(NULL));
-
-Also, the PNG logo (in PNG format, of course) is supplied in the
-files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
-
-Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is a
-certification mark of the Open Source Initiative.
-
-Glenn Randers-Pehrson
-glennrp at users.sourceforge.net
-March 29, 2012
-
-.\" end of man page
-
diff --git a/extern/libpng/include/libpng.pc.in b/extern/libpng/include/libpng.pc.in
deleted file mode 100644
index 3e7e2c58a7..0000000000
--- a/extern/libpng/include/libpng.pc.in
+++ /dev/null
@@ -1,11 +0,0 @@
-prefix=@prefix@
-exec_prefix=@exec_prefix@
-libdir=@libdir@
-includedir=@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
-
-Name: libpng
-Description: Loads and saves PNG files
-Version: @PNGLIB_VERSION@
-Libs: -L${libdir} -lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
-Libs.private: @LIBS@
-Cflags: -I${includedir}
diff --git a/extern/libpng/include/libpngpf.3 b/extern/libpng/include/libpngpf.3
deleted file mode 100644
index 8449f173f9..0000000000
--- a/extern/libpng/include/libpngpf.3
+++ /dev/null
@@ -1,28 +0,0 @@
-.TH LIBPNGPF 3 "March 29, 2012"
-.SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.5.10
-(private functions)
-.SH SYNOPSIS
-\fB#include \fI"pngpriv.h"
-
-\fI\fB
-
-\fBAs of libpng version \fP\fI1.5.1\fP\fB, this section is no longer \fP\fImaintained\fP\fB, now \fIthat
-
-\fBthe private function prototypes are hidden in pngpriv.h and not \fIaccessible
-
-\fBto applications. Look in pngpriv.h for the prototypes and a short \fIdescription
-
-\fBof each \fIfunction.
-
-\fI\fB
-
-.SH DESCRIPTION
-The functions previously listed here are used privately by libpng
-and are not recommended for use by applications.  They are
-not "exported" to applications using shared libraries.
-
-.SH SEE ALSO
-.BR "png"(5), " libpng"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
-.SH AUTHOR
-Glenn Randers-Pehrson
diff --git a/extern/libpng/include/ltmain.sh b/extern/libpng/include/ltmain.sh
deleted file mode 100755
index 63ae69dc6f..0000000000
--- a/extern/libpng/include/ltmain.sh
+++ /dev/null
@@ -1,9655 +0,0 @@
-
-# libtool (GNU libtool) 2.4.2
-# Written by Gordon Matzigkeit <gord@gnu.ai.mit.edu>, 1996
-
-# Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006,
-# 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
-# This is free software; see the source for copying conditions.  There is NO
-# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
-
-# GNU Libtool is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# As a special exception to the GNU General Public License,
-# if you distribute this file as part of a program or library that
-# is built using GNU Libtool, you may include this file under the
-# same distribution terms that you use for the rest of that program.
-#
-# GNU Libtool is distributed in the hope that it will be useful, but
-# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with GNU Libtool; see the file COPYING.  If not, a copy
-# can be downloaded from http://www.gnu.org/licenses/gpl.html,
-# or obtained by writing to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-
-# Usage: $progname [OPTION]... [MODE-ARG]...
-#
-# Provide generalized library-building support services.
-#
-#       --config             show all configuration variables
-#       --debug              enable verbose shell tracing
-#   -n, --dry-run            display commands without modifying any files
-#       --features           display basic configuration information and exit
-#       --mode=MODE          use operation mode MODE
-#       --preserve-dup-deps  don't remove duplicate dependency libraries
-#       --quiet, --silent    don't print informational messages
-#       --no-quiet, --no-silent
-#                            print informational messages (default)
-#       --no-warn            don't display warning messages
-#       --tag=TAG            use configuration variables from tag TAG
-#   -v, --verbose            print more informational messages than default
-#       --no-verbose         don't print the extra informational messages
-#       --version            print version information
-#   -h, --help, --help-all   print short, long, or detailed help message
-#
-# MODE must be one of the following:
-#
-#         clean              remove files from the build directory
-#         compile            compile a source file into a libtool object
-#         execute            automatically set library path, then run a program
-#         finish             complete the installation of libtool libraries
-#         install            install libraries or executables
-#         link               create a library or an executable
-#         uninstall          remove libraries from an installed directory
-#
-# MODE-ARGS vary depending on the MODE.  When passed as first option,
-# `--mode=MODE' may be abbreviated as `MODE' or a unique abbreviation of that.
-# Try `$progname --help --mode=MODE' for a more detailed description of MODE.
-#
-# When reporting a bug, please describe a test case to reproduce it and
-# include the following information:
-#
-#         host-triplet:	$host
-#         shell:		$SHELL
-#         compiler:		$LTCC
-#         compiler flags:		$LTCFLAGS
-#         linker:		$LD (gnu? $with_gnu_ld)
-#         $progname:	(GNU libtool) 2.4.2
-#         automake:	$automake_version
-#         autoconf:	$autoconf_version
-#
-# Report bugs to <bug-libtool@gnu.org>.
-# GNU libtool home page: <http://www.gnu.org/software/libtool/>.
-# General help using GNU software: <http://www.gnu.org/gethelp/>.
-
-PROGRAM=libtool
-PACKAGE=libtool
-VERSION=2.4.2
-TIMESTAMP=""
-package_revision=1.3337
-
-# Be Bourne compatible
-if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
-  emulate sh
-  NULLCMD=:
-  # Zsh 3.x and 4.x performs word splitting on ${1+"$@"}, which
-  # is contrary to our usage.  Disable this feature.
-  alias -g '${1+"$@"}'='"$@"'
-  setopt NO_GLOB_SUBST
-else
-  case `(set -o) 2>/dev/null` in *posix*) set -o posix;; esac
-fi
-BIN_SH=xpg4; export BIN_SH # for Tru64
-DUALCASE=1; export DUALCASE # for MKS sh
-
-# A function that is used when there is no print builtin or printf.
-func_fallback_echo ()
-{
-  eval 'cat <<_LTECHO_EOF
-$1
-_LTECHO_EOF'
-}
-
-# NLS nuisances: We save the old values to restore during execute mode.
-lt_user_locale=
-lt_safe_locale=
-for lt_var in LANG LANGUAGE LC_ALL LC_CTYPE LC_COLLATE LC_MESSAGES
-do
-  eval "if test \"\${$lt_var+set}\" = set; then
-          save_$lt_var=\$$lt_var
-          $lt_var=C
-	  export $lt_var
-	  lt_user_locale=\"$lt_var=\\\$save_\$lt_var; \$lt_user_locale\"
-	  lt_safe_locale=\"$lt_var=C; \$lt_safe_locale\"
-	fi"
-done
-LC_ALL=C
-LANGUAGE=C
-export LANGUAGE LC_ALL
-
-$lt_unset CDPATH
-
-
-# Work around backward compatibility issue on IRIX 6.5. On IRIX 6.4+, sh
-# is ksh but when the shell is invoked as "sh" and the current value of
-# the _XPG environment variable is not equal to 1 (one), the special
-# positional parameter $0, within a function call, is the name of the
-# function.
-progpath="$0"
-
-
-
-: ${CP="cp -f"}
-test "${ECHO+set}" = set || ECHO=${as_echo-'printf %s\n'}
-: ${MAKE="make"}
-: ${MKDIR="mkdir"}
-: ${MV="mv -f"}
-: ${RM="rm -f"}
-: ${SHELL="${CONFIG_SHELL-/bin/sh}"}
-: ${Xsed="$SED -e 1s/^X//"}
-
-# Global variables:
-EXIT_SUCCESS=0
-EXIT_FAILURE=1
-EXIT_MISMATCH=63  # $? = 63 is used to indicate version mismatch to missing.
-EXIT_SKIP=77	  # $? = 77 is used to indicate a skipped test to automake.
-
-exit_status=$EXIT_SUCCESS
-
-# Make sure IFS has a sensible default
-lt_nl='
-'
-IFS=" 	$lt_nl"
-
-dirname="s,/[^/]*$,,"
-basename="s,^.*/,,"
-
-# func_dirname file append nondir_replacement
-# Compute the dirname of FILE.  If nonempty, add APPEND to the result,
-# otherwise set result to NONDIR_REPLACEMENT.
-func_dirname ()
-{
-    func_dirname_result=`$ECHO "${1}" | $SED "$dirname"`
-    if test "X$func_dirname_result" = "X${1}"; then
-      func_dirname_result="${3}"
-    else
-      func_dirname_result="$func_dirname_result${2}"
-    fi
-} # func_dirname may be replaced by extended shell implementation
-
-
-# func_basename file
-func_basename ()
-{
-    func_basename_result=`$ECHO "${1}" | $SED "$basename"`
-} # func_basename may be replaced by extended shell implementation
-
-
-# func_dirname_and_basename file append nondir_replacement
-# perform func_basename and func_dirname in a single function
-# call:
-#   dirname:  Compute the dirname of FILE.  If nonempty,
-#             add APPEND to the result, otherwise set result
-#             to NONDIR_REPLACEMENT.
-#             value returned in "$func_dirname_result"
-#   basename: Compute filename of FILE.
-#             value retuned in "$func_basename_result"
-# Implementation must be kept synchronized with func_dirname
-# and func_basename. For efficiency, we do not delegate to
-# those functions but instead duplicate the functionality here.
-func_dirname_and_basename ()
-{
-    # Extract subdirectory from the argument.
-    func_dirname_result=`$ECHO "${1}" | $SED -e "$dirname"`
-    if test "X$func_dirname_result" = "X${1}"; then
-      func_dirname_result="${3}"
-    else
-      func_dirname_result="$func_dirname_result${2}"
-    fi
-    func_basename_result=`$ECHO "${1}" | $SED -e "$basename"`
-} # func_dirname_and_basename may be replaced by extended shell implementation
-
-
-# func_stripname prefix suffix name
-# strip PREFIX and SUFFIX off of NAME.
-# PREFIX and SUFFIX must not contain globbing or regex special
-# characters, hashes, percent signs, but SUFFIX may contain a leading
-# dot (in which case that matches only a dot).
-# func_strip_suffix prefix name
-func_stripname ()
-{
-    case ${2} in
-      .*) func_stripname_result=`$ECHO "${3}" | $SED "s%^${1}%%; s%\\\\${2}\$%%"`;;
-      *)  func_stripname_result=`$ECHO "${3}" | $SED "s%^${1}%%; s%${2}\$%%"`;;
-    esac
-} # func_stripname may be replaced by extended shell implementation
-
-
-# These SED scripts presuppose an absolute path with a trailing slash.
-pathcar='s,^/\([^/]*\).*$,\1,'
-pathcdr='s,^/[^/]*,,'
-removedotparts=':dotsl
-		s@/\./@/@g
-		t dotsl
-		s,/\.$,/,'
-collapseslashes='s@/\{1,\}@/@g'
-finalslash='s,/*$,/,'
-
-# func_normal_abspath PATH
-# Remove doubled-up and trailing slashes, "." path components,
-# and cancel out any ".." path components in PATH after making
-# it an absolute path.
-#             value returned in "$func_normal_abspath_result"
-func_normal_abspath ()
-{
-  # Start from root dir and reassemble the path.
-  func_normal_abspath_result=
-  func_normal_abspath_tpath=$1
-  func_normal_abspath_altnamespace=
-  case $func_normal_abspath_tpath in
-    "")
-      # Empty path, that just means $cwd.
-      func_stripname '' '/' "`pwd`"
-      func_normal_abspath_result=$func_stripname_result
-      return
-    ;;
-    # The next three entries are used to spot a run of precisely
-    # two leading slashes without using negated character classes;
-    # we take advantage of case's first-match behaviour.
-    ///*)
-      # Unusual form of absolute path, do nothing.
-    ;;
-    //*)
-      # Not necessarily an ordinary path; POSIX reserves leading '//'
-      # and for example Cygwin uses it to access remote file shares
-      # over CIFS/SMB, so we conserve a leading double slash if found.
-      func_normal_abspath_altnamespace=/
-    ;;
-    /*)
-      # Absolute path, do nothing.
-    ;;
-    *)
-      # Relative path, prepend $cwd.
-      func_normal_abspath_tpath=`pwd`/$func_normal_abspath_tpath
-    ;;
-  esac
-  # Cancel out all the simple stuff to save iterations.  We also want
-  # the path to end with a slash for ease of parsing, so make sure
-  # there is one (and only one) here.
-  func_normal_abspath_tpath=`$ECHO "$func_normal_abspath_tpath" | $SED \
-        -e "$removedotparts" -e "$collapseslashes" -e "$finalslash"`
-  while :; do
-    # Processed it all yet?
-    if test "$func_normal_abspath_tpath" = / ; then
-      # If we ascended to the root using ".." the result may be empty now.
-      if test -z "$func_normal_abspath_result" ; then
-        func_normal_abspath_result=/
-      fi
-      break
-    fi
-    func_normal_abspath_tcomponent=`$ECHO "$func_normal_abspath_tpath" | $SED \
-        -e "$pathcar"`
-    func_normal_abspath_tpath=`$ECHO "$func_normal_abspath_tpath" | $SED \
-        -e "$pathcdr"`
-    # Figure out what to do with it
-    case $func_normal_abspath_tcomponent in
-      "")
-        # Trailing empty path component, ignore it.
-      ;;
-      ..)
-        # Parent dir; strip last assembled component from result.
-        func_dirname "$func_normal_abspath_result"
-        func_normal_abspath_result=$func_dirname_result
-      ;;
-      *)
-        # Actual path component, append it.
-        func_normal_abspath_result=$func_normal_abspath_result/$func_normal_abspath_tcomponent
-      ;;
-    esac
-  done
-  # Restore leading double-slash if one was found on entry.
-  func_normal_abspath_result=$func_normal_abspath_altnamespace$func_normal_abspath_result
-}
-
-# func_relative_path SRCDIR DSTDIR
-# generates a relative path from SRCDIR to DSTDIR, with a trailing
-# slash if non-empty, suitable for immediately appending a filename
-# without needing to append a separator.
-#             value returned in "$func_relative_path_result"
-func_relative_path ()
-{
-  func_relative_path_result=
-  func_normal_abspath "$1"
-  func_relative_path_tlibdir=$func_normal_abspath_result
-  func_normal_abspath "$2"
-  func_relative_path_tbindir=$func_normal_abspath_result
-
-  # Ascend the tree starting from libdir
-  while :; do
-    # check if we have found a prefix of bindir
-    case $func_relative_path_tbindir in
-      $func_relative_path_tlibdir)
-        # found an exact match
-        func_relative_path_tcancelled=
-        break
-        ;;
-      $func_relative_path_tlibdir*)
-        # found a matching prefix
-        func_stripname "$func_relative_path_tlibdir" '' "$func_relative_path_tbindir"
-        func_relative_path_tcancelled=$func_stripname_result
-        if test -z "$func_relative_path_result"; then
-          func_relative_path_result=.
-        fi
-        break
-        ;;
-      *)
-        func_dirname $func_relative_path_tlibdir
-        func_relative_path_tlibdir=${func_dirname_result}
-        if test "x$func_relative_path_tlibdir" = x ; then
-          # Have to descend all the way to the root!
-          func_relative_path_result=../$func_relative_path_result
-          func_relative_path_tcancelled=$func_relative_path_tbindir
-          break
-        fi
-        func_relative_path_result=../$func_relative_path_result
-        ;;
-    esac
-  done
-
-  # Now calculate path; take care to avoid doubling-up slashes.
-  func_stripname '' '/' "$func_relative_path_result"
-  func_relative_path_result=$func_stripname_result
-  func_stripname '/' '/' "$func_relative_path_tcancelled"
-  if test "x$func_stripname_result" != x ; then
-    func_relative_path_result=${func_relative_path_result}/${func_stripname_result}
-  fi
-
-  # Normalisation. If bindir is libdir, return empty string,
-  # else relative path ending with a slash; either way, target
-  # file name can be directly appended.
-  if test ! -z "$func_relative_path_result"; then
-    func_stripname './' '' "$func_relative_path_result/"
-    func_relative_path_result=$func_stripname_result
-  fi
-}
-
-# The name of this program:
-func_dirname_and_basename "$progpath"
-progname=$func_basename_result
-
-# Make sure we have an absolute path for reexecution:
-case $progpath in
-  [\\/]*|[A-Za-z]:\\*) ;;
-  *[\\/]*)
-     progdir=$func_dirname_result
-     progdir=`cd "$progdir" && pwd`
-     progpath="$progdir/$progname"
-     ;;
-  *)
-     save_IFS="$IFS"
-     IFS=${PATH_SEPARATOR-:}
-     for progdir in $PATH; do
-       IFS="$save_IFS"
-       test -x "$progdir/$progname" && break
-     done
-     IFS="$save_IFS"
-     test -n "$progdir" || progdir=`pwd`
-     progpath="$progdir/$progname"
-     ;;
-esac
-
-# Sed substitution that helps us do robust quoting.  It backslashifies
-# metacharacters that are still active within double-quoted strings.
-Xsed="${SED}"' -e 1s/^X//'
-sed_quote_subst='s/\([`"$\\]\)/\\\1/g'
-
-# Same as above, but do not quote variable references.
-double_quote_subst='s/\(["`\\]\)/\\\1/g'
-
-# Sed substitution that turns a string into a regex matching for the
-# string literally.
-sed_make_literal_regex='s,[].[^$\\*\/],\\&,g'
-
-# Sed substitution that converts a w32 file name or path
-# which contains forward slashes, into one that contains
-# (escaped) backslashes.  A very naive implementation.
-lt_sed_naive_backslashify='s|\\\\*|\\|g;s|/|\\|g;s|\\|\\\\|g'
-
-# Re-`\' parameter expansions in output of double_quote_subst that were
-# `\'-ed in input to the same.  If an odd number of `\' preceded a '$'
-# in input to double_quote_subst, that '$' was protected from expansion.
-# Since each input `\' is now two `\'s, look for any number of runs of
-# four `\'s followed by two `\'s and then a '$'.  `\' that '$'.
-bs='\\'
-bs2='\\\\'
-bs4='\\\\\\\\'
-dollar='\$'
-sed_double_backslash="\
-  s/$bs4/&\\
-/g
-  s/^$bs2$dollar/$bs&/
-  s/\\([^$bs]\\)$bs2$dollar/\\1$bs2$bs$dollar/g
-  s/\n//g"
-
-# Standard options:
-opt_dry_run=false
-opt_help=false
-opt_quiet=false
-opt_verbose=false
-opt_warning=:
-
-# func_echo arg...
-# Echo program name prefixed message, along with the current mode
-# name if it has been set yet.
-func_echo ()
-{
-    $ECHO "$progname: ${opt_mode+$opt_mode: }$*"
-}
-
-# func_verbose arg...
-# Echo program name prefixed message in verbose mode only.
-func_verbose ()
-{
-    $opt_verbose && func_echo ${1+"$@"}
-
-    # A bug in bash halts the script if the last line of a function
-    # fails when set -e is in force, so we need another command to
-    # work around that:
-    :
-}
-
-# func_echo_all arg...
-# Invoke $ECHO with all args, space-separated.
-func_echo_all ()
-{
-    $ECHO "$*"
-}
-
-# func_error arg...
-# Echo program name prefixed message to standard error.
-func_error ()
-{
-    $ECHO "$progname: ${opt_mode+$opt_mode: }"${1+"$@"} 1>&2
-}
-
-# func_warning arg...
-# Echo program name prefixed warning message to standard error.
-func_warning ()
-{
-    $opt_warning && $ECHO "$progname: ${opt_mode+$opt_mode: }warning: "${1+"$@"} 1>&2
-
-    # bash bug again:
-    :
-}
-
-# func_fatal_error arg...
-# Echo program name prefixed message to standard error, and exit.
-func_fatal_error ()
-{
-    func_error ${1+"$@"}
-    exit $EXIT_FAILURE
-}
-
-# func_fatal_help arg...
-# Echo program name prefixed message to standard error, followed by
-# a help hint, and exit.
-func_fatal_help ()
-{
-    func_error ${1+"$@"}
-    func_fatal_error "$help"
-}
-help="Try \`$progname --help' for more information."  ## default
-
-
-# func_grep expression filename
-# Check whether EXPRESSION matches any line of FILENAME, without output.
-func_grep ()
-{
-    $GREP "$1" "$2" >/dev/null 2>&1
-}
-
-
-# func_mkdir_p directory-path
-# Make sure the entire path to DIRECTORY-PATH is available.
-func_mkdir_p ()
-{
-    my_directory_path="$1"
-    my_dir_list=
-
-    if test -n "$my_directory_path" && test "$opt_dry_run" != ":"; then
-
-      # Protect directory names starting with `-'
-      case $my_directory_path in
-        -*) my_directory_path="./$my_directory_path" ;;
-      esac
-
-      # While some portion of DIR does not yet exist...
-      while test ! -d "$my_directory_path"; do
-        # ...make a list in topmost first order.  Use a colon delimited
-	# list incase some portion of path contains whitespace.
-        my_dir_list="$my_directory_path:$my_dir_list"
-
-        # If the last portion added has no slash in it, the list is done
-        case $my_directory_path in */*) ;; *) break ;; esac
-
-        # ...otherwise throw away the child directory and loop
-        my_directory_path=`$ECHO "$my_directory_path" | $SED -e "$dirname"`
-      done
-      my_dir_list=`$ECHO "$my_dir_list" | $SED 's,:*$,,'`
-
-      save_mkdir_p_IFS="$IFS"; IFS=':'
-      for my_dir in $my_dir_list; do
-	IFS="$save_mkdir_p_IFS"
-        # mkdir can fail with a `File exist' error if two processes
-        # try to create one of the directories concurrently.  Don't
-        # stop in that case!
-        $MKDIR "$my_dir" 2>/dev/null || :
-      done
-      IFS="$save_mkdir_p_IFS"
-
-      # Bail out if we (or some other process) failed to create a directory.
-      test -d "$my_directory_path" || \
-        func_fatal_error "Failed to create \`$1'"
-    fi
-}
-
-
-# func_mktempdir [string]
-# Make a temporary directory that won't clash with other running
-# libtool processes, and avoids race conditions if possible.  If
-# given, STRING is the basename for that directory.
-func_mktempdir ()
-{
-    my_template="${TMPDIR-/tmp}/${1-$progname}"
-
-    if test "$opt_dry_run" = ":"; then
-      # Return a directory name, but don't create it in dry-run mode
-      my_tmpdir="${my_template}-$$"
-    else
-
-      # If mktemp works, use that first and foremost
-      my_tmpdir=`mktemp -d "${my_template}-XXXXXXXX" 2>/dev/null`
-
-      if test ! -d "$my_tmpdir"; then
-        # Failing that, at least try and use $RANDOM to avoid a race
-        my_tmpdir="${my_template}-${RANDOM-0}$$"
-
-        save_mktempdir_umask=`umask`
-        umask 0077
-        $MKDIR "$my_tmpdir"
-        umask $save_mktempdir_umask
-      fi
-
-      # If we're not in dry-run mode, bomb out on failure
-      test -d "$my_tmpdir" || \
-        func_fatal_error "cannot create temporary directory \`$my_tmpdir'"
-    fi
-
-    $ECHO "$my_tmpdir"
-}
-
-
-# func_quote_for_eval arg
-# Aesthetically quote ARG to be evaled later.
-# This function returns two values: FUNC_QUOTE_FOR_EVAL_RESULT
-# is double-quoted, suitable for a subsequent eval, whereas
-# FUNC_QUOTE_FOR_EVAL_UNQUOTED_RESULT has merely all characters
-# which are still active within double quotes backslashified.
-func_quote_for_eval ()
-{
-    case $1 in
-      *[\\\`\"\$]*)
-	func_quote_for_eval_unquoted_result=`$ECHO "$1" | $SED "$sed_quote_subst"` ;;
-      *)
-        func_quote_for_eval_unquoted_result="$1" ;;
-    esac
-
-    case $func_quote_for_eval_unquoted_result in
-      # Double-quote args containing shell metacharacters to delay
-      # word splitting, command substitution and and variable
-      # expansion for a subsequent eval.
-      # Many Bourne shells cannot handle close brackets correctly
-      # in scan sets, so we specify it separately.
-      *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
-        func_quote_for_eval_result="\"$func_quote_for_eval_unquoted_result\""
-        ;;
-      *)
-        func_quote_for_eval_result="$func_quote_for_eval_unquoted_result"
-    esac
-}
-
-
-# func_quote_for_expand arg
-# Aesthetically quote ARG to be evaled later; same as above,
-# but do not quote variable references.
-func_quote_for_expand ()
-{
-    case $1 in
-      *[\\\`\"]*)
-	my_arg=`$ECHO "$1" | $SED \
-	    -e "$double_quote_subst" -e "$sed_double_backslash"` ;;
-      *)
-        my_arg="$1" ;;
-    esac
-
-    case $my_arg in
-      # Double-quote args containing shell metacharacters to delay
-      # word splitting and command substitution for a subsequent eval.
-      # Many Bourne shells cannot handle close brackets correctly
-      # in scan sets, so we specify it separately.
-      *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
-        my_arg="\"$my_arg\""
-        ;;
-    esac
-
-    func_quote_for_expand_result="$my_arg"
-}
-
-
-# func_show_eval cmd [fail_exp]
-# Unless opt_silent is true, then output CMD.  Then, if opt_dryrun is
-# not true, evaluate CMD.  If the evaluation of CMD fails, and FAIL_EXP
-# is given, then evaluate it.
-func_show_eval ()
-{
-    my_cmd="$1"
-    my_fail_exp="${2-:}"
-
-    ${opt_silent-false} || {
-      func_quote_for_expand "$my_cmd"
-      eval "func_echo $func_quote_for_expand_result"
-    }
-
-    if ${opt_dry_run-false}; then :; else
-      eval "$my_cmd"
-      my_status=$?
-      if test "$my_status" -eq 0; then :; else
-	eval "(exit $my_status); $my_fail_exp"
-      fi
-    fi
-}
-
-
-# func_show_eval_locale cmd [fail_exp]
-# Unless opt_silent is true, then output CMD.  Then, if opt_dryrun is
-# not true, evaluate CMD.  If the evaluation of CMD fails, and FAIL_EXP
-# is given, then evaluate it.  Use the saved locale for evaluation.
-func_show_eval_locale ()
-{
-    my_cmd="$1"
-    my_fail_exp="${2-:}"
-
-    ${opt_silent-false} || {
-      func_quote_for_expand "$my_cmd"
-      eval "func_echo $func_quote_for_expand_result"
-    }
-
-    if ${opt_dry_run-false}; then :; else
-      eval "$lt_user_locale
-	    $my_cmd"
-      my_status=$?
-      eval "$lt_safe_locale"
-      if test "$my_status" -eq 0; then :; else
-	eval "(exit $my_status); $my_fail_exp"
-      fi
-    fi
-}
-
-# func_tr_sh
-# Turn $1 into a string suitable for a shell variable name.
-# Result is stored in $func_tr_sh_result.  All characters
-# not in the set a-zA-Z0-9_ are replaced with '_'. Further,
-# if $1 begins with a digit, a '_' is prepended as well.
-func_tr_sh ()
-{
-  case $1 in
-  [0-9]* | *[!a-zA-Z0-9_]*)
-    func_tr_sh_result=`$ECHO "$1" | $SED 's/^\([0-9]\)/_\1/; s/[^a-zA-Z0-9_]/_/g'`
-    ;;
-  * )
-    func_tr_sh_result=$1
-    ;;
-  esac
-}
-
-
-# func_version
-# Echo version message to standard output and exit.
-func_version ()
-{
-    $opt_debug
-
-    $SED -n '/(C)/!b go
-	:more
-	/\./!{
-	  N
-	  s/\n# / /
-	  b more
-	}
-	:go
-	/^# '$PROGRAM' (GNU /,/# warranty; / {
-        s/^# //
-	s/^# *$//
-        s/\((C)\)[ 0-9,-]*\( [1-9][0-9]*\)/\1\2/
-        p
-     }' < "$progpath"
-     exit $?
-}
-
-# func_usage
-# Echo short help message to standard output and exit.
-func_usage ()
-{
-    $opt_debug
-
-    $SED -n '/^# Usage:/,/^#  *.*--help/ {
-        s/^# //
-	s/^# *$//
-	s/\$progname/'$progname'/
-	p
-    }' < "$progpath"
-    echo
-    $ECHO "run \`$progname --help | more' for full usage"
-    exit $?
-}
-
-# func_help [NOEXIT]
-# Echo long help message to standard output and exit,
-# unless 'noexit' is passed as argument.
-func_help ()
-{
-    $opt_debug
-
-    $SED -n '/^# Usage:/,/# Report bugs to/ {
-	:print
-        s/^# //
-	s/^# *$//
-	s*\$progname*'$progname'*
-	s*\$host*'"$host"'*
-	s*\$SHELL*'"$SHELL"'*
-	s*\$LTCC*'"$LTCC"'*
-	s*\$LTCFLAGS*'"$LTCFLAGS"'*
-	s*\$LD*'"$LD"'*
-	s/\$with_gnu_ld/'"$with_gnu_ld"'/
-	s/\$automake_version/'"`(${AUTOMAKE-automake} --version) 2>/dev/null |$SED 1q`"'/
-	s/\$autoconf_version/'"`(${AUTOCONF-autoconf} --version) 2>/dev/null |$SED 1q`"'/
-	p
-	d
-     }
-     /^# .* home page:/b print
-     /^# General help using/b print
-     ' < "$progpath"
-    ret=$?
-    if test -z "$1"; then
-      exit $ret
-    fi
-}
-
-# func_missing_arg argname
-# Echo program name prefixed message to standard error and set global
-# exit_cmd.
-func_missing_arg ()
-{
-    $opt_debug
-
-    func_error "missing argument for $1."
-    exit_cmd=exit
-}
-
-
-# func_split_short_opt shortopt
-# Set func_split_short_opt_name and func_split_short_opt_arg shell
-# variables after splitting SHORTOPT after the 2nd character.
-func_split_short_opt ()
-{
-    my_sed_short_opt='1s/^\(..\).*$/\1/;q'
-    my_sed_short_rest='1s/^..\(.*\)$/\1/;q'
-
-    func_split_short_opt_name=`$ECHO "$1" | $SED "$my_sed_short_opt"`
-    func_split_short_opt_arg=`$ECHO "$1" | $SED "$my_sed_short_rest"`
-} # func_split_short_opt may be replaced by extended shell implementation
-
-
-# func_split_long_opt longopt
-# Set func_split_long_opt_name and func_split_long_opt_arg shell
-# variables after splitting LONGOPT at the `=' sign.
-func_split_long_opt ()
-{
-    my_sed_long_opt='1s/^\(--[^=]*\)=.*/\1/;q'
-    my_sed_long_arg='1s/^--[^=]*=//'
-
-    func_split_long_opt_name=`$ECHO "$1" | $SED "$my_sed_long_opt"`
-    func_split_long_opt_arg=`$ECHO "$1" | $SED "$my_sed_long_arg"`
-} # func_split_long_opt may be replaced by extended shell implementation
-
-exit_cmd=:
-
-
-
-
-
-magic="%%%MAGIC variable%%%"
-magic_exe="%%%MAGIC EXE variable%%%"
-
-# Global variables.
-nonopt=
-preserve_args=
-lo2o="s/\\.lo\$/.${objext}/"
-o2lo="s/\\.${objext}\$/.lo/"
-extracted_archives=
-extracted_serial=0
-
-# If this variable is set in any of the actions, the command in it
-# will be execed at the end.  This prevents here-documents from being
-# left over by shells.
-exec_cmd=
-
-# func_append var value
-# Append VALUE to the end of shell variable VAR.
-func_append ()
-{
-    eval "${1}=\$${1}\${2}"
-} # func_append may be replaced by extended shell implementation
-
-# func_append_quoted var value
-# Quote VALUE and append to the end of shell variable VAR, separated
-# by a space.
-func_append_quoted ()
-{
-    func_quote_for_eval "${2}"
-    eval "${1}=\$${1}\\ \$func_quote_for_eval_result"
-} # func_append_quoted may be replaced by extended shell implementation
-
-
-# func_arith arithmetic-term...
-func_arith ()
-{
-    func_arith_result=`expr "${@}"`
-} # func_arith may be replaced by extended shell implementation
-
-
-# func_len string
-# STRING may not start with a hyphen.
-func_len ()
-{
-    func_len_result=`expr "${1}" : ".*" 2>/dev/null || echo $max_cmd_len`
-} # func_len may be replaced by extended shell implementation
-
-
-# func_lo2o object
-func_lo2o ()
-{
-    func_lo2o_result=`$ECHO "${1}" | $SED "$lo2o"`
-} # func_lo2o may be replaced by extended shell implementation
-
-
-# func_xform libobj-or-source
-func_xform ()
-{
-    func_xform_result=`$ECHO "${1}" | $SED 's/\.[^.]*$/.lo/'`
-} # func_xform may be replaced by extended shell implementation
-
-
-# func_fatal_configuration arg...
-# Echo program name prefixed message to standard error, followed by
-# a configuration failure hint, and exit.
-func_fatal_configuration ()
-{
-    func_error ${1+"$@"}
-    func_error "See the $PACKAGE documentation for more information."
-    func_fatal_error "Fatal configuration error."
-}
-
-
-# func_config
-# Display the configuration for all the tags in this script.
-func_config ()
-{
-    re_begincf='^# ### BEGIN LIBTOOL'
-    re_endcf='^# ### END LIBTOOL'
-
-    # Default configuration.
-    $SED "1,/$re_begincf CONFIG/d;/$re_endcf CONFIG/,\$d" < "$progpath"
-
-    # Now print the configurations for the tags.
-    for tagname in $taglist; do
-      $SED -n "/$re_begincf TAG CONFIG: $tagname\$/,/$re_endcf TAG CONFIG: $tagname\$/p" < "$progpath"
-    done
-
-    exit $?
-}
-
-# func_features
-# Display the features supported by this script.
-func_features ()
-{
-    echo "host: $host"
-    if test "$build_libtool_libs" = yes; then
-      echo "enable shared libraries"
-    else
-      echo "disable shared libraries"
-    fi
-    if test "$build_old_libs" = yes; then
-      echo "enable static libraries"
-    else
-      echo "disable static libraries"
-    fi
-
-    exit $?
-}
-
-# func_enable_tag tagname
-# Verify that TAGNAME is valid, and either flag an error and exit, or
-# enable the TAGNAME tag.  We also add TAGNAME to the global $taglist
-# variable here.
-func_enable_tag ()
-{
-  # Global variable:
-  tagname="$1"
-
-  re_begincf="^# ### BEGIN LIBTOOL TAG CONFIG: $tagname\$"
-  re_endcf="^# ### END LIBTOOL TAG CONFIG: $tagname\$"
-  sed_extractcf="/$re_begincf/,/$re_endcf/p"
-
-  # Validate tagname.
-  case $tagname in
-    *[!-_A-Za-z0-9,/]*)
-      func_fatal_error "invalid tag name: $tagname"
-      ;;
-  esac
-
-  # Don't test for the "default" C tag, as we know it's
-  # there but not specially marked.
-  case $tagname in
-    CC) ;;
-    *)
-      if $GREP "$re_begincf" "$progpath" >/dev/null 2>&1; then
-	taglist="$taglist $tagname"
-
-	# Evaluate the configuration.  Be careful to quote the path
-	# and the sed script, to avoid splitting on whitespace, but
-	# also don't use non-portable quotes within backquotes within
-	# quotes we have to do it in 2 steps:
-	extractedcf=`$SED -n -e "$sed_extractcf" < "$progpath"`
-	eval "$extractedcf"
-      else
-	func_error "ignoring unknown tag $tagname"
-      fi
-      ;;
-  esac
-}
-
-# func_check_version_match
-# Ensure that we are using m4 macros, and libtool script from the same
-# release of libtool.
-func_check_version_match ()
-{
-  if test "$package_revision" != "$macro_revision"; then
-    if test "$VERSION" != "$macro_version"; then
-      if test -z "$macro_version"; then
-        cat >&2 <<_LT_EOF
-$progname: Version mismatch error.  This is $PACKAGE $VERSION, but the
-$progname: definition of this LT_INIT comes from an older release.
-$progname: You should recreate aclocal.m4 with macros from $PACKAGE $VERSION
-$progname: and run autoconf again.
-_LT_EOF
-      else
-        cat >&2 <<_LT_EOF
-$progname: Version mismatch error.  This is $PACKAGE $VERSION, but the
-$progname: definition of this LT_INIT comes from $PACKAGE $macro_version.
-$progname: You should recreate aclocal.m4 with macros from $PACKAGE $VERSION
-$progname: and run autoconf again.
-_LT_EOF
-      fi
-    else
-      cat >&2 <<_LT_EOF
-$progname: Version mismatch error.  This is $PACKAGE $VERSION, revision $package_revision,
-$progname: but the definition of this LT_INIT comes from revision $macro_revision.
-$progname: You should recreate aclocal.m4 with macros from revision $package_revision
-$progname: of $PACKAGE $VERSION and run autoconf again.
-_LT_EOF
-    fi
-
-    exit $EXIT_MISMATCH
-  fi
-}
-
-
-# Shorthand for --mode=foo, only valid as the first argument
-case $1 in
-clean|clea|cle|cl)
-  shift; set dummy --mode clean ${1+"$@"}; shift
-  ;;
-compile|compil|compi|comp|com|co|c)
-  shift; set dummy --mode compile ${1+"$@"}; shift
-  ;;
-execute|execut|execu|exec|exe|ex|e)
-  shift; set dummy --mode execute ${1+"$@"}; shift
-  ;;
-finish|finis|fini|fin|fi|f)
-  shift; set dummy --mode finish ${1+"$@"}; shift
-  ;;
-install|instal|insta|inst|ins|in|i)
-  shift; set dummy --mode install ${1+"$@"}; shift
-  ;;
-link|lin|li|l)
-  shift; set dummy --mode link ${1+"$@"}; shift
-  ;;
-uninstall|uninstal|uninsta|uninst|unins|unin|uni|un|u)
-  shift; set dummy --mode uninstall ${1+"$@"}; shift
-  ;;
-esac
-
-
-
-# Option defaults:
-opt_debug=:
-opt_dry_run=false
-opt_config=false
-opt_preserve_dup_deps=false
-opt_features=false
-opt_finish=false
-opt_help=false
-opt_help_all=false
-opt_silent=:
-opt_warning=:
-opt_verbose=:
-opt_silent=false
-opt_verbose=false
-
-
-# Parse options once, thoroughly.  This comes as soon as possible in the
-# script to make things like `--version' happen as quickly as we can.
-{
-  # this just eases exit handling
-  while test $# -gt 0; do
-    opt="$1"
-    shift
-    case $opt in
-      --debug|-x)	opt_debug='set -x'
-			func_echo "enabling shell trace mode"
-			$opt_debug
-			;;
-      --dry-run|--dryrun|-n)
-			opt_dry_run=:
-			;;
-      --config)
-			opt_config=:
-func_config
-			;;
-      --dlopen|-dlopen)
-			optarg="$1"
-			opt_dlopen="${opt_dlopen+$opt_dlopen
-}$optarg"
-			shift
-			;;
-      --preserve-dup-deps)
-			opt_preserve_dup_deps=:
-			;;
-      --features)
-			opt_features=:
-func_features
-			;;
-      --finish)
-			opt_finish=:
-set dummy --mode finish ${1+"$@"}; shift
-			;;
-      --help)
-			opt_help=:
-			;;
-      --help-all)
-			opt_help_all=:
-opt_help=': help-all'
-			;;
-      --mode)
-			test $# = 0 && func_missing_arg $opt && break
-			optarg="$1"
-			opt_mode="$optarg"
-case $optarg in
-  # Valid mode arguments:
-  clean|compile|execute|finish|install|link|relink|uninstall) ;;
-
-  # Catch anything else as an error
-  *) func_error "invalid argument for $opt"
-     exit_cmd=exit
-     break
-     ;;
-esac
-			shift
-			;;
-      --no-silent|--no-quiet)
-			opt_silent=false
-func_append preserve_args " $opt"
-			;;
-      --no-warning|--no-warn)
-			opt_warning=false
-func_append preserve_args " $opt"
-			;;
-      --no-verbose)
-			opt_verbose=false
-func_append preserve_args " $opt"
-			;;
-      --silent|--quiet)
-			opt_silent=:
-func_append preserve_args " $opt"
-        opt_verbose=false
-			;;
-      --verbose|-v)
-			opt_verbose=:
-func_append preserve_args " $opt"
-opt_silent=false
-			;;
-      --tag)
-			test $# = 0 && func_missing_arg $opt && break
-			optarg="$1"
-			opt_tag="$optarg"
-func_append preserve_args " $opt $optarg"
-func_enable_tag "$optarg"
-			shift
-			;;
-
-      -\?|-h)		func_usage				;;
-      --help)		func_help				;;
-      --version)	func_version				;;
-
-      # Separate optargs to long options:
-      --*=*)
-			func_split_long_opt "$opt"
-			set dummy "$func_split_long_opt_name" "$func_split_long_opt_arg" ${1+"$@"}
-			shift
-			;;
-
-      # Separate non-argument short options:
-      -\?*|-h*|-n*|-v*)
-			func_split_short_opt "$opt"
-			set dummy "$func_split_short_opt_name" "-$func_split_short_opt_arg" ${1+"$@"}
-			shift
-			;;
-
-      --)		break					;;
-      -*)		func_fatal_help "unrecognized option \`$opt'" ;;
-      *)		set dummy "$opt" ${1+"$@"};	shift; break  ;;
-    esac
-  done
-
-  # Validate options:
-
-  # save first non-option argument
-  if test "$#" -gt 0; then
-    nonopt="$opt"
-    shift
-  fi
-
-  # preserve --debug
-  test "$opt_debug" = : || func_append preserve_args " --debug"
-
-  case $host in
-    *cygwin* | *mingw* | *pw32* | *cegcc*)
-      # don't eliminate duplications in $postdeps and $predeps
-      opt_duplicate_compiler_generated_deps=:
-      ;;
-    *)
-      opt_duplicate_compiler_generated_deps=$opt_preserve_dup_deps
-      ;;
-  esac
-
-  $opt_help || {
-    # Sanity checks first:
-    func_check_version_match
-
-    if test "$build_libtool_libs" != yes && test "$build_old_libs" != yes; then
-      func_fatal_configuration "not configured to build any kind of library"
-    fi
-
-    # Darwin sucks
-    eval std_shrext=\"$shrext_cmds\"
-
-    # Only execute mode is allowed to have -dlopen flags.
-    if test -n "$opt_dlopen" && test "$opt_mode" != execute; then
-      func_error "unrecognized option \`-dlopen'"
-      $ECHO "$help" 1>&2
-      exit $EXIT_FAILURE
-    fi
-
-    # Change the help message to a mode-specific one.
-    generic_help="$help"
-    help="Try \`$progname --help --mode=$opt_mode' for more information."
-  }
-
-
-  # Bail if the options were screwed
-  $exit_cmd $EXIT_FAILURE
-}
-
-
-
-
-## ----------- ##
-##    Main.    ##
-## ----------- ##
-
-# func_lalib_p file
-# True iff FILE is a libtool `.la' library or `.lo' object file.
-# This function is only a basic sanity check; it will hardly flush out
-# determined imposters.
-func_lalib_p ()
-{
-    test -f "$1" &&
-      $SED -e 4q "$1" 2>/dev/null \
-        | $GREP "^# Generated by .*$PACKAGE" > /dev/null 2>&1
-}
-
-# func_lalib_unsafe_p file
-# True iff FILE is a libtool `.la' library or `.lo' object file.
-# This function implements the same check as func_lalib_p without
-# resorting to external programs.  To this end, it redirects stdin and
-# closes it afterwards, without saving the original file descriptor.
-# As a safety measure, use it only where a negative result would be
-# fatal anyway.  Works if `file' does not exist.
-func_lalib_unsafe_p ()
-{
-    lalib_p=no
-    if test -f "$1" && test -r "$1" && exec 5<&0 <"$1"; then
-	for lalib_p_l in 1 2 3 4
-	do
-	    read lalib_p_line
-	    case "$lalib_p_line" in
-		\#\ Generated\ by\ *$PACKAGE* ) lalib_p=yes; break;;
-	    esac
-	done
-	exec 0<&5 5<&-
-    fi
-    test "$lalib_p" = yes
-}
-
-# func_ltwrapper_script_p file
-# True iff FILE is a libtool wrapper script
-# This function is only a basic sanity check; it will hardly flush out
-# determined imposters.
-func_ltwrapper_script_p ()
-{
-    func_lalib_p "$1"
-}
-
-# func_ltwrapper_executable_p file
-# True iff FILE is a libtool wrapper executable
-# This function is only a basic sanity check; it will hardly flush out
-# determined imposters.
-func_ltwrapper_executable_p ()
-{
-    func_ltwrapper_exec_suffix=
-    case $1 in
-    *.exe) ;;
-    *) func_ltwrapper_exec_suffix=.exe ;;
-    esac
-    $GREP "$magic_exe" "$1$func_ltwrapper_exec_suffix" >/dev/null 2>&1
-}
-
-# func_ltwrapper_scriptname file
-# Assumes file is an ltwrapper_executable
-# uses $file to determine the appropriate filename for a
-# temporary ltwrapper_script.
-func_ltwrapper_scriptname ()
-{
-    func_dirname_and_basename "$1" "" "."
-    func_stripname '' '.exe' "$func_basename_result"
-    func_ltwrapper_scriptname_result="$func_dirname_result/$objdir/${func_stripname_result}_ltshwrapper"
-}
-
-# func_ltwrapper_p file
-# True iff FILE is a libtool wrapper script or wrapper executable
-# This function is only a basic sanity check; it will hardly flush out
-# determined imposters.
-func_ltwrapper_p ()
-{
-    func_ltwrapper_script_p "$1" || func_ltwrapper_executable_p "$1"
-}
-
-
-# func_execute_cmds commands fail_cmd
-# Execute tilde-delimited COMMANDS.
-# If FAIL_CMD is given, eval that upon failure.
-# FAIL_CMD may read-access the current command in variable CMD!
-func_execute_cmds ()
-{
-    $opt_debug
-    save_ifs=$IFS; IFS='~'
-    for cmd in $1; do
-      IFS=$save_ifs
-      eval cmd=\"$cmd\"
-      func_show_eval "$cmd" "${2-:}"
-    done
-    IFS=$save_ifs
-}
-
-
-# func_source file
-# Source FILE, adding directory component if necessary.
-# Note that it is not necessary on cygwin/mingw to append a dot to
-# FILE even if both FILE and FILE.exe exist: automatic-append-.exe
-# behavior happens only for exec(3), not for open(2)!  Also, sourcing
-# `FILE.' does not work on cygwin managed mounts.
-func_source ()
-{
-    $opt_debug
-    case $1 in
-    */* | *\\*)	. "$1" ;;
-    *)		. "./$1" ;;
-    esac
-}
-
-
-# func_resolve_sysroot PATH
-# Replace a leading = in PATH with a sysroot.  Store the result into
-# func_resolve_sysroot_result
-func_resolve_sysroot ()
-{
-  func_resolve_sysroot_result=$1
-  case $func_resolve_sysroot_result in
-  =*)
-    func_stripname '=' '' "$func_resolve_sysroot_result"
-    func_resolve_sysroot_result=$lt_sysroot$func_stripname_result
-    ;;
-  esac
-}
-
-# func_replace_sysroot PATH
-# If PATH begins with the sysroot, replace it with = and
-# store the result into func_replace_sysroot_result.
-func_replace_sysroot ()
-{
-  case "$lt_sysroot:$1" in
-  ?*:"$lt_sysroot"*)
-    func_stripname "$lt_sysroot" '' "$1"
-    func_replace_sysroot_result="=$func_stripname_result"
-    ;;
-  *)
-    # Including no sysroot.
-    func_replace_sysroot_result=$1
-    ;;
-  esac
-}
-
-# func_infer_tag arg
-# Infer tagged configuration to use if any are available and
-# if one wasn't chosen via the "--tag" command line option.
-# Only attempt this if the compiler in the base compile
-# command doesn't match the default compiler.
-# arg is usually of the form 'gcc ...'
-func_infer_tag ()
-{
-    $opt_debug
-    if test -n "$available_tags" && test -z "$tagname"; then
-      CC_quoted=
-      for arg in $CC; do
-	func_append_quoted CC_quoted "$arg"
-      done
-      CC_expanded=`func_echo_all $CC`
-      CC_quoted_expanded=`func_echo_all $CC_quoted`
-      case $@ in
-      # Blanks in the command may have been stripped by the calling shell,
-      # but not from the CC environment variable when configure was run.
-      " $CC "* | "$CC "* | " $CC_expanded "* | "$CC_expanded "* | \
-      " $CC_quoted"* | "$CC_quoted "* | " $CC_quoted_expanded "* | "$CC_quoted_expanded "*) ;;
-      # Blanks at the start of $base_compile will cause this to fail
-      # if we don't check for them as well.
-      *)
-	for z in $available_tags; do
-	  if $GREP "^# ### BEGIN LIBTOOL TAG CONFIG: $z$" < "$progpath" > /dev/null; then
-	    # Evaluate the configuration.
-	    eval "`${SED} -n -e '/^# ### BEGIN LIBTOOL TAG CONFIG: '$z'$/,/^# ### END LIBTOOL TAG CONFIG: '$z'$/p' < $progpath`"
-	    CC_quoted=
-	    for arg in $CC; do
-	      # Double-quote args containing other shell metacharacters.
-	      func_append_quoted CC_quoted "$arg"
-	    done
-	    CC_expanded=`func_echo_all $CC`
-	    CC_quoted_expanded=`func_echo_all $CC_quoted`
-	    case "$@ " in
-	    " $CC "* | "$CC "* | " $CC_expanded "* | "$CC_expanded "* | \
-	    " $CC_quoted"* | "$CC_quoted "* | " $CC_quoted_expanded "* | "$CC_quoted_expanded "*)
-	      # The compiler in the base compile command matches
-	      # the one in the tagged configuration.
-	      # Assume this is the tagged configuration we want.
-	      tagname=$z
-	      break
-	      ;;
-	    esac
-	  fi
-	done
-	# If $tagname still isn't set, then no tagged configuration
-	# was found and let the user know that the "--tag" command
-	# line option must be used.
-	if test -z "$tagname"; then
-	  func_echo "unable to infer tagged configuration"
-	  func_fatal_error "specify a tag with \`--tag'"
-#	else
-#	  func_verbose "using $tagname tagged configuration"
-	fi
-	;;
-      esac
-    fi
-}
-
-
-
-# func_write_libtool_object output_name pic_name nonpic_name
-# Create a libtool object file (analogous to a ".la" file),
-# but don't create it if we're doing a dry run.
-func_write_libtool_object ()
-{
-    write_libobj=${1}
-    if test "$build_libtool_libs" = yes; then
-      write_lobj=\'${2}\'
-    else
-      write_lobj=none
-    fi
-
-    if test "$build_old_libs" = yes; then
-      write_oldobj=\'${3}\'
-    else
-      write_oldobj=none
-    fi
-
-    $opt_dry_run || {
-      cat >${write_libobj}T <<EOF
-# $write_libobj - a libtool object file
-# Generated by $PROGRAM (GNU $PACKAGE$TIMESTAMP) $VERSION
-#
-# Please DO NOT delete this file!
-# It is necessary for linking the library.
-
-# Name of the PIC object.
-pic_object=$write_lobj
-
-# Name of the non-PIC object
-non_pic_object=$write_oldobj
-
-EOF
-      $MV "${write_libobj}T" "${write_libobj}"
-    }
-}
-
-
-##################################################
-# FILE NAME AND PATH CONVERSION HELPER FUNCTIONS #
-##################################################
-
-# func_convert_core_file_wine_to_w32 ARG
-# Helper function used by file name conversion functions when $build is *nix,
-# and $host is mingw, cygwin, or some other w32 environment. Relies on a
-# correctly configured wine environment available, with the winepath program
-# in $build's $PATH.
-#
-# ARG is the $build file name to be converted to w32 format.
-# Result is available in $func_convert_core_file_wine_to_w32_result, and will
-# be empty on error (or when ARG is empty)
-func_convert_core_file_wine_to_w32 ()
-{
-  $opt_debug
-  func_convert_core_file_wine_to_w32_result="$1"
-  if test -n "$1"; then
-    # Unfortunately, winepath does not exit with a non-zero error code, so we
-    # are forced to check the contents of stdout. On the other hand, if the
-    # command is not found, the shell will set an exit code of 127 and print
-    # *an error message* to stdout. So we must check for both error code of
-    # zero AND non-empty stdout, which explains the odd construction:
-    func_convert_core_file_wine_to_w32_tmp=`winepath -w "$1" 2>/dev/null`
-    if test "$?" -eq 0 && test -n "${func_convert_core_file_wine_to_w32_tmp}"; then
-      func_convert_core_file_wine_to_w32_result=`$ECHO "$func_convert_core_file_wine_to_w32_tmp" |
-        $SED -e "$lt_sed_naive_backslashify"`
-    else
-      func_convert_core_file_wine_to_w32_result=
-    fi
-  fi
-}
-# end: func_convert_core_file_wine_to_w32
-
-
-# func_convert_core_path_wine_to_w32 ARG
-# Helper function used by path conversion functions when $build is *nix, and
-# $host is mingw, cygwin, or some other w32 environment. Relies on a correctly
-# configured wine environment available, with the winepath program in $build's
-# $PATH. Assumes ARG has no leading or trailing path separator characters.
-#
-# ARG is path to be converted from $build format to win32.
-# Result is available in $func_convert_core_path_wine_to_w32_result.
-# Unconvertible file (directory) names in ARG are skipped; if no directory names
-# are convertible, then the result may be empty.
-func_convert_core_path_wine_to_w32 ()
-{
-  $opt_debug
-  # unfortunately, winepath doesn't convert paths, only file names
-  func_convert_core_path_wine_to_w32_result=""
-  if test -n "$1"; then
-    oldIFS=$IFS
-    IFS=:
-    for func_convert_core_path_wine_to_w32_f in $1; do
-      IFS=$oldIFS
-      func_convert_core_file_wine_to_w32 "$func_convert_core_path_wine_to_w32_f"
-      if test -n "$func_convert_core_file_wine_to_w32_result" ; then
-        if test -z "$func_convert_core_path_wine_to_w32_result"; then
-          func_convert_core_path_wine_to_w32_result="$func_convert_core_file_wine_to_w32_result"
-        else
-          func_append func_convert_core_path_wine_to_w32_result ";$func_convert_core_file_wine_to_w32_result"
-        fi
-      fi
-    done
-    IFS=$oldIFS
-  fi
-}
-# end: func_convert_core_path_wine_to_w32
-
-
-# func_cygpath ARGS...
-# Wrapper around calling the cygpath program via LT_CYGPATH. This is used when
-# when (1) $build is *nix and Cygwin is hosted via a wine environment; or (2)
-# $build is MSYS and $host is Cygwin, or (3) $build is Cygwin. In case (1) or
-# (2), returns the Cygwin file name or path in func_cygpath_result (input
-# file name or path is assumed to be in w32 format, as previously converted
-# from $build's *nix or MSYS format). In case (3), returns the w32 file name
-# or path in func_cygpath_result (input file name or path is assumed to be in
-# Cygwin format). Returns an empty string on error.
-#
-# ARGS are passed to cygpath, with the last one being the file name or path to
-# be converted.
-#
-# Specify the absolute *nix (or w32) name to cygpath in the LT_CYGPATH
-# environment variable; do not put it in $PATH.
-func_cygpath ()
-{
-  $opt_debug
-  if test -n "$LT_CYGPATH" && test -f "$LT_CYGPATH"; then
-    func_cygpath_result=`$LT_CYGPATH "$@" 2>/dev/null`
-    if test "$?" -ne 0; then
-      # on failure, ensure result is empty
-      func_cygpath_result=
-    fi
-  else
-    func_cygpath_result=
-    func_error "LT_CYGPATH is empty or specifies non-existent file: \`$LT_CYGPATH'"
-  fi
-}
-#end: func_cygpath
-
-
-# func_convert_core_msys_to_w32 ARG
-# Convert file name or path ARG from MSYS format to w32 format.  Return
-# result in func_convert_core_msys_to_w32_result.
-func_convert_core_msys_to_w32 ()
-{
-  $opt_debug
-  # awkward: cmd appends spaces to result
-  func_convert_core_msys_to_w32_result=`( cmd //c echo "$1" ) 2>/dev/null |
-    $SED -e 's/[ ]*$//' -e "$lt_sed_naive_backslashify"`
-}
-#end: func_convert_core_msys_to_w32
-
-
-# func_convert_file_check ARG1 ARG2
-# Verify that ARG1 (a file name in $build format) was converted to $host
-# format in ARG2. Otherwise, emit an error message, but continue (resetting
-# func_to_host_file_result to ARG1).
-func_convert_file_check ()
-{
-  $opt_debug
-  if test -z "$2" && test -n "$1" ; then
-    func_error "Could not determine host file name corresponding to"
-    func_error "  \`$1'"
-    func_error "Continuing, but uninstalled executables may not work."
-    # Fallback:
-    func_to_host_file_result="$1"
-  fi
-}
-# end func_convert_file_check
-
-
-# func_convert_path_check FROM_PATHSEP TO_PATHSEP FROM_PATH TO_PATH
-# Verify that FROM_PATH (a path in $build format) was converted to $host
-# format in TO_PATH. Otherwise, emit an error message, but continue, resetting
-# func_to_host_file_result to a simplistic fallback value (see below).
-func_convert_path_check ()
-{
-  $opt_debug
-  if test -z "$4" && test -n "$3"; then
-    func_error "Could not determine the host path corresponding to"
-    func_error "  \`$3'"
-    func_error "Continuing, but uninstalled executables may not work."
-    # Fallback.  This is a deliberately simplistic "conversion" and
-    # should not be "improved".  See libtool.info.
-    if test "x$1" != "x$2"; then
-      lt_replace_pathsep_chars="s|$1|$2|g"
-      func_to_host_path_result=`echo "$3" |
-        $SED -e "$lt_replace_pathsep_chars"`
-    else
-      func_to_host_path_result="$3"
-    fi
-  fi
-}
-# end func_convert_path_check
-
-
-# func_convert_path_front_back_pathsep FRONTPAT BACKPAT REPL ORIG
-# Modifies func_to_host_path_result by prepending REPL if ORIG matches FRONTPAT
-# and appending REPL if ORIG matches BACKPAT.
-func_convert_path_front_back_pathsep ()
-{
-  $opt_debug
-  case $4 in
-  $1 ) func_to_host_path_result="$3$func_to_host_path_result"
-    ;;
-  esac
-  case $4 in
-  $2 ) func_append func_to_host_path_result "$3"
-    ;;
-  esac
-}
-# end func_convert_path_front_back_pathsep
-
-
-##################################################
-# $build to $host FILE NAME CONVERSION FUNCTIONS #
-##################################################
-# invoked via `$to_host_file_cmd ARG'
-#
-# In each case, ARG is the path to be converted from $build to $host format.
-# Result will be available in $func_to_host_file_result.
-
-
-# func_to_host_file ARG
-# Converts the file name ARG from $build format to $host format. Return result
-# in func_to_host_file_result.
-func_to_host_file ()
-{
-  $opt_debug
-  $to_host_file_cmd "$1"
-}
-# end func_to_host_file
-
-
-# func_to_tool_file ARG LAZY
-# converts the file name ARG from $build format to toolchain format. Return
-# result in func_to_tool_file_result.  If the conversion in use is listed
-# in (the comma separated) LAZY, no conversion takes place.
-func_to_tool_file ()
-{
-  $opt_debug
-  case ,$2, in
-    *,"$to_tool_file_cmd",*)
-      func_to_tool_file_result=$1
-      ;;
-    *)
-      $to_tool_file_cmd "$1"
-      func_to_tool_file_result=$func_to_host_file_result
-      ;;
-  esac
-}
-# end func_to_tool_file
-
-
-# func_convert_file_noop ARG
-# Copy ARG to func_to_host_file_result.
-func_convert_file_noop ()
-{
-  func_to_host_file_result="$1"
-}
-# end func_convert_file_noop
-
-
-# func_convert_file_msys_to_w32 ARG
-# Convert file name ARG from (mingw) MSYS to (mingw) w32 format; automatic
-# conversion to w32 is not available inside the cwrapper.  Returns result in
-# func_to_host_file_result.
-func_convert_file_msys_to_w32 ()
-{
-  $opt_debug
-  func_to_host_file_result="$1"
-  if test -n "$1"; then
-    func_convert_core_msys_to_w32 "$1"
-    func_to_host_file_result="$func_convert_core_msys_to_w32_result"
-  fi
-  func_convert_file_check "$1" "$func_to_host_file_result"
-}
-# end func_convert_file_msys_to_w32
-
-
-# func_convert_file_cygwin_to_w32 ARG
-# Convert file name ARG from Cygwin to w32 format.  Returns result in
-# func_to_host_file_result.
-func_convert_file_cygwin_to_w32 ()
-{
-  $opt_debug
-  func_to_host_file_result="$1"
-  if test -n "$1"; then
-    # because $build is cygwin, we call "the" cygpath in $PATH; no need to use
-    # LT_CYGPATH in this case.
-    func_to_host_file_result=`cygpath -m "$1"`
-  fi
-  func_convert_file_check "$1" "$func_to_host_file_result"
-}
-# end func_convert_file_cygwin_to_w32
-
-
-# func_convert_file_nix_to_w32 ARG
-# Convert file name ARG from *nix to w32 format.  Requires a wine environment
-# and a working winepath. Returns result in func_to_host_file_result.
-func_convert_file_nix_to_w32 ()
-{
-  $opt_debug
-  func_to_host_file_result="$1"
-  if test -n "$1"; then
-    func_convert_core_file_wine_to_w32 "$1"
-    func_to_host_file_result="$func_convert_core_file_wine_to_w32_result"
-  fi
-  func_convert_file_check "$1" "$func_to_host_file_result"
-}
-# end func_convert_file_nix_to_w32
-
-
-# func_convert_file_msys_to_cygwin ARG
-# Convert file name ARG from MSYS to Cygwin format.  Requires LT_CYGPATH set.
-# Returns result in func_to_host_file_result.
-func_convert_file_msys_to_cygwin ()
-{
-  $opt_debug
-  func_to_host_file_result="$1"
-  if test -n "$1"; then
-    func_convert_core_msys_to_w32 "$1"
-    func_cygpath -u "$func_convert_core_msys_to_w32_result"
-    func_to_host_file_result="$func_cygpath_result"
-  fi
-  func_convert_file_check "$1" "$func_to_host_file_result"
-}
-# end func_convert_file_msys_to_cygwin
-
-
-# func_convert_file_nix_to_cygwin ARG
-# Convert file name ARG from *nix to Cygwin format.  Requires Cygwin installed
-# in a wine environment, working winepath, and LT_CYGPATH set.  Returns result
-# in func_to_host_file_result.
-func_convert_file_nix_to_cygwin ()
-{
-  $opt_debug
-  func_to_host_file_result="$1"
-  if test -n "$1"; then
-    # convert from *nix to w32, then use cygpath to convert from w32 to cygwin.
-    func_convert_core_file_wine_to_w32 "$1"
-    func_cygpath -u "$func_convert_core_file_wine_to_w32_result"
-    func_to_host_file_result="$func_cygpath_result"
-  fi
-  func_convert_file_check "$1" "$func_to_host_file_result"
-}
-# end func_convert_file_nix_to_cygwin
-
-
-#############################################
-# $build to $host PATH CONVERSION FUNCTIONS #
-#############################################
-# invoked via `$to_host_path_cmd ARG'
-#
-# In each case, ARG is the path to be converted from $build to $host format.
-# The result will be available in $func_to_host_path_result.
-#
-# Path separators are also converted from $build format to $host format.  If
-# ARG begins or ends with a path separator character, it is preserved (but
-# converted to $host format) on output.
-#
-# All path conversion functions are named using the following convention:
-#   file name conversion function    : func_convert_file_X_to_Y ()
-#   path conversion function         : func_convert_path_X_to_Y ()
-# where, for any given $build/$host combination the 'X_to_Y' value is the
-# same.  If conversion functions are added for new $build/$host combinations,
-# the two new functions must follow this pattern, or func_init_to_host_path_cmd
-# will break.
-
-
-# func_init_to_host_path_cmd
-# Ensures that function "pointer" variable $to_host_path_cmd is set to the
-# appropriate value, based on the value of $to_host_file_cmd.
-to_host_path_cmd=
-func_init_to_host_path_cmd ()
-{
-  $opt_debug
-  if test -z "$to_host_path_cmd"; then
-    func_stripname 'func_convert_file_' '' "$to_host_file_cmd"
-    to_host_path_cmd="func_convert_path_${func_stripname_result}"
-  fi
-}
-
-
-# func_to_host_path ARG
-# Converts the path ARG from $build format to $host format. Return result
-# in func_to_host_path_result.
-func_to_host_path ()
-{
-  $opt_debug
-  func_init_to_host_path_cmd
-  $to_host_path_cmd "$1"
-}
-# end func_to_host_path
-
-
-# func_convert_path_noop ARG
-# Copy ARG to func_to_host_path_result.
-func_convert_path_noop ()
-{
-  func_to_host_path_result="$1"
-}
-# end func_convert_path_noop
-
-
-# func_convert_path_msys_to_w32 ARG
-# Convert path ARG from (mingw) MSYS to (mingw) w32 format; automatic
-# conversion to w32 is not available inside the cwrapper.  Returns result in
-# func_to_host_path_result.
-func_convert_path_msys_to_w32 ()
-{
-  $opt_debug
-  func_to_host_path_result="$1"
-  if test -n "$1"; then
-    # Remove leading and trailing path separator characters from ARG.  MSYS
-    # behavior is inconsistent here; cygpath turns them into '.;' and ';.';
-    # and winepath ignores them completely.
-    func_stripname : : "$1"
-    func_to_host_path_tmp1=$func_stripname_result
-    func_convert_core_msys_to_w32 "$func_to_host_path_tmp1"
-    func_to_host_path_result="$func_convert_core_msys_to_w32_result"
-    func_convert_path_check : ";" \
-      "$func_to_host_path_tmp1" "$func_to_host_path_result"
-    func_convert_path_front_back_pathsep ":*" "*:" ";" "$1"
-  fi
-}
-# end func_convert_path_msys_to_w32
-
-
-# func_convert_path_cygwin_to_w32 ARG
-# Convert path ARG from Cygwin to w32 format.  Returns result in
-# func_to_host_file_result.
-func_convert_path_cygwin_to_w32 ()
-{
-  $opt_debug
-  func_to_host_path_result="$1"
-  if test -n "$1"; then
-    # See func_convert_path_msys_to_w32:
-    func_stripname : : "$1"
-    func_to_host_path_tmp1=$func_stripname_result
-    func_to_host_path_result=`cygpath -m -p "$func_to_host_path_tmp1"`
-    func_convert_path_check : ";" \
-      "$func_to_host_path_tmp1" "$func_to_host_path_result"
-    func_convert_path_front_back_pathsep ":*" "*:" ";" "$1"
-  fi
-}
-# end func_convert_path_cygwin_to_w32
-
-
-# func_convert_path_nix_to_w32 ARG
-# Convert path ARG from *nix to w32 format.  Requires a wine environment and
-# a working winepath.  Returns result in func_to_host_file_result.
-func_convert_path_nix_to_w32 ()
-{
-  $opt_debug
-  func_to_host_path_result="$1"
-  if test -n "$1"; then
-    # See func_convert_path_msys_to_w32:
-    func_stripname : : "$1"
-    func_to_host_path_tmp1=$func_stripname_result
-    func_convert_core_path_wine_to_w32 "$func_to_host_path_tmp1"
-    func_to_host_path_result="$func_convert_core_path_wine_to_w32_result"
-    func_convert_path_check : ";" \
-      "$func_to_host_path_tmp1" "$func_to_host_path_result"
-    func_convert_path_front_back_pathsep ":*" "*:" ";" "$1"
-  fi
-}
-# end func_convert_path_nix_to_w32
-
-
-# func_convert_path_msys_to_cygwin ARG
-# Convert path ARG from MSYS to Cygwin format.  Requires LT_CYGPATH set.
-# Returns result in func_to_host_file_result.
-func_convert_path_msys_to_cygwin ()
-{
-  $opt_debug
-  func_to_host_path_result="$1"
-  if test -n "$1"; then
-    # See func_convert_path_msys_to_w32:
-    func_stripname : : "$1"
-    func_to_host_path_tmp1=$func_stripname_result
-    func_convert_core_msys_to_w32 "$func_to_host_path_tmp1"
-    func_cygpath -u -p "$func_convert_core_msys_to_w32_result"
-    func_to_host_path_result="$func_cygpath_result"
-    func_convert_path_check : : \
-      "$func_to_host_path_tmp1" "$func_to_host_path_result"
-    func_convert_path_front_back_pathsep ":*" "*:" : "$1"
-  fi
-}
-# end func_convert_path_msys_to_cygwin
-
-
-# func_convert_path_nix_to_cygwin ARG
-# Convert path ARG from *nix to Cygwin format.  Requires Cygwin installed in a
-# a wine environment, working winepath, and LT_CYGPATH set.  Returns result in
-# func_to_host_file_result.
-func_convert_path_nix_to_cygwin ()
-{
-  $opt_debug
-  func_to_host_path_result="$1"
-  if test -n "$1"; then
-    # Remove leading and trailing path separator characters from
-    # ARG. msys behavior is inconsistent here, cygpath turns them
-    # into '.;' and ';.', and winepath ignores them completely.
-    func_stripname : : "$1"
-    func_to_host_path_tmp1=$func_stripname_result
-    func_convert_core_path_wine_to_w32 "$func_to_host_path_tmp1"
-    func_cygpath -u -p "$func_convert_core_path_wine_to_w32_result"
-    func_to_host_path_result="$func_cygpath_result"
-    func_convert_path_check : : \
-      "$func_to_host_path_tmp1" "$func_to_host_path_result"
-    func_convert_path_front_back_pathsep ":*" "*:" : "$1"
-  fi
-}
-# end func_convert_path_nix_to_cygwin
-
-
-# func_mode_compile arg...
-func_mode_compile ()
-{
-    $opt_debug
-    # Get the compilation command and the source file.
-    base_compile=
-    srcfile="$nonopt"  #  always keep a non-empty value in "srcfile"
-    suppress_opt=yes
-    suppress_output=
-    arg_mode=normal
-    libobj=
-    later=
-    pie_flag=
-
-    for arg
-    do
-      case $arg_mode in
-      arg  )
-	# do not "continue".  Instead, add this to base_compile
-	lastarg="$arg"
-	arg_mode=normal
-	;;
-
-      target )
-	libobj="$arg"
-	arg_mode=normal
-	continue
-	;;
-
-      normal )
-	# Accept any command-line options.
-	case $arg in
-	-o)
-	  test -n "$libobj" && \
-	    func_fatal_error "you cannot specify \`-o' more than once"
-	  arg_mode=target
-	  continue
-	  ;;
-
-	-pie | -fpie | -fPIE)
-          func_append pie_flag " $arg"
-	  continue
-	  ;;
-
-	-shared | -static | -prefer-pic | -prefer-non-pic)
-	  func_append later " $arg"
-	  continue
-	  ;;
-
-	-no-suppress)
-	  suppress_opt=no
-	  continue
-	  ;;
-
-	-Xcompiler)
-	  arg_mode=arg  #  the next one goes into the "base_compile" arg list
-	  continue      #  The current "srcfile" will either be retained or
-	  ;;            #  replaced later.  I would guess that would be a bug.
-
-	-Wc,*)
-	  func_stripname '-Wc,' '' "$arg"
-	  args=$func_stripname_result
-	  lastarg=
-	  save_ifs="$IFS"; IFS=','
-	  for arg in $args; do
-	    IFS="$save_ifs"
-	    func_append_quoted lastarg "$arg"
-	  done
-	  IFS="$save_ifs"
-	  func_stripname ' ' '' "$lastarg"
-	  lastarg=$func_stripname_result
-
-	  # Add the arguments to base_compile.
-	  func_append base_compile " $lastarg"
-	  continue
-	  ;;
-
-	*)
-	  # Accept the current argument as the source file.
-	  # The previous "srcfile" becomes the current argument.
-	  #
-	  lastarg="$srcfile"
-	  srcfile="$arg"
-	  ;;
-	esac  #  case $arg
-	;;
-      esac    #  case $arg_mode
-
-      # Aesthetically quote the previous argument.
-      func_append_quoted base_compile "$lastarg"
-    done # for arg
-
-    case $arg_mode in
-    arg)
-      func_fatal_error "you must specify an argument for -Xcompile"
-      ;;
-    target)
-      func_fatal_error "you must specify a target with \`-o'"
-      ;;
-    *)
-      # Get the name of the library object.
-      test -z "$libobj" && {
-	func_basename "$srcfile"
-	libobj="$func_basename_result"
-      }
-      ;;
-    esac
-
-    # Recognize several different file suffixes.
-    # If the user specifies -o file.o, it is replaced with file.lo
-    case $libobj in
-    *.[cCFSifmso] | \
-    *.ada | *.adb | *.ads | *.asm | \
-    *.c++ | *.cc | *.ii | *.class | *.cpp | *.cxx | \
-    *.[fF][09]? | *.for | *.java | *.go | *.obj | *.sx | *.cu | *.cup)
-      func_xform "$libobj"
-      libobj=$func_xform_result
-      ;;
-    esac
-
-    case $libobj in
-    *.lo) func_lo2o "$libobj"; obj=$func_lo2o_result ;;
-    *)
-      func_fatal_error "cannot determine name of library object from \`$libobj'"
-      ;;
-    esac
-
-    func_infer_tag $base_compile
-
-    for arg in $later; do
-      case $arg in
-      -shared)
-	test "$build_libtool_libs" != yes && \
-	  func_fatal_configuration "can not build a shared library"
-	build_old_libs=no
-	continue
-	;;
-
-      -static)
-	build_libtool_libs=no
-	build_old_libs=yes
-	continue
-	;;
-
-      -prefer-pic)
-	pic_mode=yes
-	continue
-	;;
-
-      -prefer-non-pic)
-	pic_mode=no
-	continue
-	;;
-      esac
-    done
-
-    func_quote_for_eval "$libobj"
-    test "X$libobj" != "X$func_quote_for_eval_result" \
-      && $ECHO "X$libobj" | $GREP '[]~#^*{};<>?"'"'"'	 &()|`$[]' \
-      && func_warning "libobj name \`$libobj' may not contain shell special characters."
-    func_dirname_and_basename "$obj" "/" ""
-    objname="$func_basename_result"
-    xdir="$func_dirname_result"
-    lobj=${xdir}$objdir/$objname
-
-    test -z "$base_compile" && \
-      func_fatal_help "you must specify a compilation command"
-
-    # Delete any leftover library objects.
-    if test "$build_old_libs" = yes; then
-      removelist="$obj $lobj $libobj ${libobj}T"
-    else
-      removelist="$lobj $libobj ${libobj}T"
-    fi
-
-    # On Cygwin there's no "real" PIC flag so we must build both object types
-    case $host_os in
-    cygwin* | mingw* | pw32* | os2* | cegcc*)
-      pic_mode=default
-      ;;
-    esac
-    if test "$pic_mode" = no && test "$deplibs_check_method" != pass_all; then
-      # non-PIC code in shared libraries is not supported
-      pic_mode=default
-    fi
-
-    # Calculate the filename of the output object if compiler does
-    # not support -o with -c
-    if test "$compiler_c_o" = no; then
-      output_obj=`$ECHO "$srcfile" | $SED 's%^.*/%%; s%\.[^.]*$%%'`.${objext}
-      lockfile="$output_obj.lock"
-    else
-      output_obj=
-      need_locks=no
-      lockfile=
-    fi
-
-    # Lock this critical section if it is needed
-    # We use this script file to make the link, it avoids creating a new file
-    if test "$need_locks" = yes; then
-      until $opt_dry_run || ln "$progpath" "$lockfile" 2>/dev/null; do
-	func_echo "Waiting for $lockfile to be removed"
-	sleep 2
-      done
-    elif test "$need_locks" = warn; then
-      if test -f "$lockfile"; then
-	$ECHO "\
-*** ERROR, $lockfile exists and contains:
-`cat $lockfile 2>/dev/null`
-
-This indicates that another process is trying to use the same
-temporary object file, and libtool could not work around it because
-your compiler does not support \`-c' and \`-o' together.  If you
-repeat this compilation, it may succeed, by chance, but you had better
-avoid parallel builds (make -j) in this platform, or get a better
-compiler."
-
-	$opt_dry_run || $RM $removelist
-	exit $EXIT_FAILURE
-      fi
-      func_append removelist " $output_obj"
-      $ECHO "$srcfile" > "$lockfile"
-    fi
-
-    $opt_dry_run || $RM $removelist
-    func_append removelist " $lockfile"
-    trap '$opt_dry_run || $RM $removelist; exit $EXIT_FAILURE' 1 2 15
-
-    func_to_tool_file "$srcfile" func_convert_file_msys_to_w32
-    srcfile=$func_to_tool_file_result
-    func_quote_for_eval "$srcfile"
-    qsrcfile=$func_quote_for_eval_result
-
-    # Only build a PIC object if we are building libtool libraries.
-    if test "$build_libtool_libs" = yes; then
-      # Without this assignment, base_compile gets emptied.
-      fbsd_hideous_sh_bug=$base_compile
-
-      if test "$pic_mode" != no; then
-	command="$base_compile $qsrcfile $pic_flag"
-      else
-	# Don't build PIC code
-	command="$base_compile $qsrcfile"
-      fi
-
-      func_mkdir_p "$xdir$objdir"
-
-      if test -z "$output_obj"; then
-	# Place PIC objects in $objdir
-	func_append command " -o $lobj"
-      fi
-
-      func_show_eval_locale "$command"	\
-          'test -n "$output_obj" && $RM $removelist; exit $EXIT_FAILURE'
-
-      if test "$need_locks" = warn &&
-	 test "X`cat $lockfile 2>/dev/null`" != "X$srcfile"; then
-	$ECHO "\
-*** ERROR, $lockfile contains:
-`cat $lockfile 2>/dev/null`
-
-but it should contain:
-$srcfile
-
-This indicates that another process is trying to use the same
-temporary object file, and libtool could not work around it because
-your compiler does not support \`-c' and \`-o' together.  If you
-repeat this compilation, it may succeed, by chance, but you had better
-avoid parallel builds (make -j) in this platform, or get a better
-compiler."
-
-	$opt_dry_run || $RM $removelist
-	exit $EXIT_FAILURE
-      fi
-
-      # Just move the object if needed, then go on to compile the next one
-      if test -n "$output_obj" && test "X$output_obj" != "X$lobj"; then
-	func_show_eval '$MV "$output_obj" "$lobj"' \
-	  'error=$?; $opt_dry_run || $RM $removelist; exit $error'
-      fi
-
-      # Allow error messages only from the first compilation.
-      if test "$suppress_opt" = yes; then
-	suppress_output=' >/dev/null 2>&1'
-      fi
-    fi
-
-    # Only build a position-dependent object if we build old libraries.
-    if test "$build_old_libs" = yes; then
-      if test "$pic_mode" != yes; then
-	# Don't build PIC code
-	command="$base_compile $qsrcfile$pie_flag"
-      else
-	command="$base_compile $qsrcfile $pic_flag"
-      fi
-      if test "$compiler_c_o" = yes; then
-	func_append command " -o $obj"
-      fi
-
-      # Suppress compiler output if we already did a PIC compilation.
-      func_append command "$suppress_output"
-      func_show_eval_locale "$command" \
-        '$opt_dry_run || $RM $removelist; exit $EXIT_FAILURE'
-
-      if test "$need_locks" = warn &&
-	 test "X`cat $lockfile 2>/dev/null`" != "X$srcfile"; then
-	$ECHO "\
-*** ERROR, $lockfile contains:
-`cat $lockfile 2>/dev/null`
-
-but it should contain:
-$srcfile
-
-This indicates that another process is trying to use the same
-temporary object file, and libtool could not work around it because
-your compiler does not support \`-c' and \`-o' together.  If you
-repeat this compilation, it may succeed, by chance, but you had better
-avoid parallel builds (make -j) in this platform, or get a better
-compiler."
-
-	$opt_dry_run || $RM $removelist
-	exit $EXIT_FAILURE
-      fi
-
-      # Just move the object if needed
-      if test -n "$output_obj" && test "X$output_obj" != "X$obj"; then
-	func_show_eval '$MV "$output_obj" "$obj"' \
-	  'error=$?; $opt_dry_run || $RM $removelist; exit $error'
-      fi
-    fi
-
-    $opt_dry_run || {
-      func_write_libtool_object "$libobj" "$objdir/$objname" "$objname"
-
-      # Unlock the critical section if it was locked
-      if test "$need_locks" != no; then
-	removelist=$lockfile
-        $RM "$lockfile"
-      fi
-    }
-
-    exit $EXIT_SUCCESS
-}
-
-$opt_help || {
-  test "$opt_mode" = compile && func_mode_compile ${1+"$@"}
-}
-
-func_mode_help ()
-{
-    # We need to display help for each of the modes.
-    case $opt_mode in
-      "")
-        # Generic help is extracted from the usage comments
-        # at the start of this file.
-        func_help
-        ;;
-
-      clean)
-        $ECHO \
-"Usage: $progname [OPTION]... --mode=clean RM [RM-OPTION]... FILE...
-
-Remove files from the build directory.
-
-RM is the name of the program to use to delete files associated with each FILE
-(typically \`/bin/rm').  RM-OPTIONS are options (such as \`-f') to be passed
-to RM.
-
-If FILE is a libtool library, object or program, all the files associated
-with it are deleted. Otherwise, only FILE itself is deleted using RM."
-        ;;
-
-      compile)
-      $ECHO \
-"Usage: $progname [OPTION]... --mode=compile COMPILE-COMMAND... SOURCEFILE
-
-Compile a source file into a libtool library object.
-
-This mode accepts the following additional options:
-
-  -o OUTPUT-FILE    set the output file name to OUTPUT-FILE
-  -no-suppress      do not suppress compiler output for multiple passes
-  -prefer-pic       try to build PIC objects only
-  -prefer-non-pic   try to build non-PIC objects only
-  -shared           do not build a \`.o' file suitable for static linking
-  -static           only build a \`.o' file suitable for static linking
-  -Wc,FLAG          pass FLAG directly to the compiler
-
-COMPILE-COMMAND is a command to be used in creating a \`standard' object file
-from the given SOURCEFILE.
-
-The output file name is determined by removing the directory component from
-SOURCEFILE, then substituting the C source code suffix \`.c' with the
-library object suffix, \`.lo'."
-        ;;
-
-      execute)
-        $ECHO \
-"Usage: $progname [OPTION]... --mode=execute COMMAND [ARGS]...
-
-Automatically set library path, then run a program.
-
-This mode accepts the following additional options:
-
-  -dlopen FILE      add the directory containing FILE to the library path
-
-This mode sets the library path environment variable according to \`-dlopen'
-flags.
-
-If any of the ARGS are libtool executable wrappers, then they are translated
-into their corresponding uninstalled binary, and any of their required library
-directories are added to the library path.
-
-Then, COMMAND is executed, with ARGS as arguments."
-        ;;
-
-      finish)
-        $ECHO \
-"Usage: $progname [OPTION]... --mode=finish [LIBDIR]...
-
-Complete the installation of libtool libraries.
-
-Each LIBDIR is a directory that contains libtool libraries.
-
-The commands that this mode executes may require superuser privileges.  Use
-the \`--dry-run' option if you just want to see what would be executed."
-        ;;
-
-      install)
-        $ECHO \
-"Usage: $progname [OPTION]... --mode=install INSTALL-COMMAND...
-
-Install executables or libraries.
-
-INSTALL-COMMAND is the installation command.  The first component should be
-either the \`install' or \`cp' program.
-
-The following components of INSTALL-COMMAND are treated specially:
-
-  -inst-prefix-dir PREFIX-DIR  Use PREFIX-DIR as a staging area for installation
-
-The rest of the components are interpreted as arguments to that command (only
-BSD-compatible install options are recognized)."
-        ;;
-
-      link)
-        $ECHO \
-"Usage: $progname [OPTION]... --mode=link LINK-COMMAND...
-
-Link object files or libraries together to form another library, or to
-create an executable program.
-
-LINK-COMMAND is a command using the C compiler that you would use to create
-a program from several object files.
-
-The following components of LINK-COMMAND are treated specially:
-
-  -all-static       do not do any dynamic linking at all
-  -avoid-version    do not add a version suffix if possible
-  -bindir BINDIR    specify path to binaries directory (for systems where
-                    libraries must be found in the PATH setting at runtime)
-  -dlopen FILE      \`-dlpreopen' FILE if it cannot be dlopened at runtime
-  -dlpreopen FILE   link in FILE and add its symbols to lt_preloaded_symbols
-  -export-dynamic   allow symbols from OUTPUT-FILE to be resolved with dlsym(3)
-  -export-symbols SYMFILE
-                    try to export only the symbols listed in SYMFILE
-  -export-symbols-regex REGEX
-                    try to export only the symbols matching REGEX
-  -LLIBDIR          search LIBDIR for required installed libraries
-  -lNAME            OUTPUT-FILE requires the installed library libNAME
-  -module           build a library that can dlopened
-  -no-fast-install  disable the fast-install mode
-  -no-install       link a not-installable executable
-  -no-undefined     declare that a library does not refer to external symbols
-  -o OUTPUT-FILE    create OUTPUT-FILE from the specified objects
-  -objectlist FILE  Use a list of object files found in FILE to specify objects
-  -precious-files-regex REGEX
-                    don't remove output files matching REGEX
-  -release RELEASE  specify package release information
-  -rpath LIBDIR     the created library will eventually be installed in LIBDIR
-  -R[ ]LIBDIR       add LIBDIR to the runtime path of programs and libraries
-  -shared           only do dynamic linking of libtool libraries
-  -shrext SUFFIX    override the standard shared library file extension
-  -static           do not do any dynamic linking of uninstalled libtool libraries
-  -static-libtool-libs
-                    do not do any dynamic linking of libtool libraries
-  -version-info CURRENT[:REVISION[:AGE]]
-                    specify library version info [each variable defaults to 0]
-  -weak LIBNAME     declare that the target provides the LIBNAME interface
-  -Wc,FLAG
-  -Xcompiler FLAG   pass linker-specific FLAG directly to the compiler
-  -Wl,FLAG
-  -Xlinker FLAG     pass linker-specific FLAG directly to the linker
-  -XCClinker FLAG   pass link-specific FLAG to the compiler driver (CC)
-
-All other options (arguments beginning with \`-') are ignored.
-
-Every other argument is treated as a filename.  Files ending in \`.la' are
-treated as uninstalled libtool libraries, other files are standard or library
-object files.
-
-If the OUTPUT-FILE ends in \`.la', then a libtool library is created,
-only library objects (\`.lo' files) may be specified, and \`-rpath' is
-required, except when creating a convenience library.
-
-If OUTPUT-FILE ends in \`.a' or \`.lib', then a standard library is created
-using \`ar' and \`ranlib', or on Windows using \`lib'.
-
-If OUTPUT-FILE ends in \`.lo' or \`.${objext}', then a reloadable object file
-is created, otherwise an executable program is created."
-        ;;
-
-      uninstall)
-        $ECHO \
-"Usage: $progname [OPTION]... --mode=uninstall RM [RM-OPTION]... FILE...
-
-Remove libraries from an installation directory.
-
-RM is the name of the program to use to delete files associated with each FILE
-(typically \`/bin/rm').  RM-OPTIONS are options (such as \`-f') to be passed
-to RM.
-
-If FILE is a libtool library, all the files associated with it are deleted.
-Otherwise, only FILE itself is deleted using RM."
-        ;;
-
-      *)
-        func_fatal_help "invalid operation mode \`$opt_mode'"
-        ;;
-    esac
-
-    echo
-    $ECHO "Try \`$progname --help' for more information about other modes."
-}
-
-# Now that we've collected a possible --mode arg, show help if necessary
-if $opt_help; then
-  if test "$opt_help" = :; then
-    func_mode_help
-  else
-    {
-      func_help noexit
-      for opt_mode in compile link execute install finish uninstall clean; do
-	func_mode_help
-      done
-    } | sed -n '1p; 2,$s/^Usage:/  or: /p'
-    {
-      func_help noexit
-      for opt_mode in compile link execute install finish uninstall clean; do
-	echo
-	func_mode_help
-      done
-    } |
-    sed '1d
-      /^When reporting/,/^Report/{
-	H
-	d
-      }
-      $x
-      /information about other modes/d
-      /more detailed .*MODE/d
-      s/^Usage:.*--mode=\([^ ]*\) .*/Description of \1 mode:/'
-  fi
-  exit $?
-fi
-
-
-# func_mode_execute arg...
-func_mode_execute ()
-{
-    $opt_debug
-    # The first argument is the command name.
-    cmd="$nonopt"
-    test -z "$cmd" && \
-      func_fatal_help "you must specify a COMMAND"
-
-    # Handle -dlopen flags immediately.
-    for file in $opt_dlopen; do
-      test -f "$file" \
-	|| func_fatal_help "\`$file' is not a file"
-
-      dir=
-      case $file in
-      *.la)
-	func_resolve_sysroot "$file"
-	file=$func_resolve_sysroot_result
-
-	# Check to see that this really is a libtool archive.
-	func_lalib_unsafe_p "$file" \
-	  || func_fatal_help "\`$lib' is not a valid libtool archive"
-
-	# Read the libtool library.
-	dlname=
-	library_names=
-	func_source "$file"
-
-	# Skip this library if it cannot be dlopened.
-	if test -z "$dlname"; then
-	  # Warn if it was a shared library.
-	  test -n "$library_names" && \
-	    func_warning "\`$file' was not linked with \`-export-dynamic'"
-	  continue
-	fi
-
-	func_dirname "$file" "" "."
-	dir="$func_dirname_result"
-
-	if test -f "$dir/$objdir/$dlname"; then
-	  func_append dir "/$objdir"
-	else
-	  if test ! -f "$dir/$dlname"; then
-	    func_fatal_error "cannot find \`$dlname' in \`$dir' or \`$dir/$objdir'"
-	  fi
-	fi
-	;;
-
-      *.lo)
-	# Just add the directory containing the .lo file.
-	func_dirname "$file" "" "."
-	dir="$func_dirname_result"
-	;;
-
-      *)
-	func_warning "\`-dlopen' is ignored for non-libtool libraries and objects"
-	continue
-	;;
-      esac
-
-      # Get the absolute pathname.
-      absdir=`cd "$dir" && pwd`
-      test -n "$absdir" && dir="$absdir"
-
-      # Now add the directory to shlibpath_var.
-      if eval "test -z \"\$$shlibpath_var\""; then
-	eval "$shlibpath_var=\"\$dir\""
-      else
-	eval "$shlibpath_var=\"\$dir:\$$shlibpath_var\""
-      fi
-    done
-
-    # This variable tells wrapper scripts just to set shlibpath_var
-    # rather than running their programs.
-    libtool_execute_magic="$magic"
-
-    # Check if any of the arguments is a wrapper script.
-    args=
-    for file
-    do
-      case $file in
-      -* | *.la | *.lo ) ;;
-      *)
-	# Do a test to see if this is really a libtool program.
-	if func_ltwrapper_script_p "$file"; then
-	  func_source "$file"
-	  # Transform arg to wrapped name.
-	  file="$progdir/$program"
-	elif func_ltwrapper_executable_p "$file"; then
-	  func_ltwrapper_scriptname "$file"
-	  func_source "$func_ltwrapper_scriptname_result"
-	  # Transform arg to wrapped name.
-	  file="$progdir/$program"
-	fi
-	;;
-      esac
-      # Quote arguments (to preserve shell metacharacters).
-      func_append_quoted args "$file"
-    done
-
-    if test "X$opt_dry_run" = Xfalse; then
-      if test -n "$shlibpath_var"; then
-	# Export the shlibpath_var.
-	eval "export $shlibpath_var"
-      fi
-
-      # Restore saved environment variables
-      for lt_var in LANG LANGUAGE LC_ALL LC_CTYPE LC_COLLATE LC_MESSAGES
-      do
-	eval "if test \"\${save_$lt_var+set}\" = set; then
-                $lt_var=\$save_$lt_var; export $lt_var
-	      else
-		$lt_unset $lt_var
-	      fi"
-      done
-
-      # Now prepare to actually exec the command.
-      exec_cmd="\$cmd$args"
-    else
-      # Display what would be done.
-      if test -n "$shlibpath_var"; then
-	eval "\$ECHO \"\$shlibpath_var=\$$shlibpath_var\""
-	echo "export $shlibpath_var"
-      fi
-      $ECHO "$cmd$args"
-      exit $EXIT_SUCCESS
-    fi
-}
-
-test "$opt_mode" = execute && func_mode_execute ${1+"$@"}
-
-
-# func_mode_finish arg...
-func_mode_finish ()
-{
-    $opt_debug
-    libs=
-    libdirs=
-    admincmds=
-
-    for opt in "$nonopt" ${1+"$@"}
-    do
-      if test -d "$opt"; then
-	func_append libdirs " $opt"
-
-      elif test -f "$opt"; then
-	if func_lalib_unsafe_p "$opt"; then
-	  func_append libs " $opt"
-	else
-	  func_warning "\`$opt' is not a valid libtool archive"
-	fi
-
-      else
-	func_fatal_error "invalid argument \`$opt'"
-      fi
-    done
-
-    if test -n "$libs"; then
-      if test -n "$lt_sysroot"; then
-        sysroot_regex=`$ECHO "$lt_sysroot" | $SED "$sed_make_literal_regex"`
-        sysroot_cmd="s/\([ ']\)$sysroot_regex/\1/g;"
-      else
-        sysroot_cmd=
-      fi
-
-      # Remove sysroot references
-      if $opt_dry_run; then
-        for lib in $libs; do
-          echo "removing references to $lt_sysroot and \`=' prefixes from $lib"
-        done
-      else
-        tmpdir=`func_mktempdir`
-        for lib in $libs; do
-	  sed -e "${sysroot_cmd} s/\([ ']-[LR]\)=/\1/g; s/\([ ']\)=/\1/g" $lib \
-	    > $tmpdir/tmp-la
-	  mv -f $tmpdir/tmp-la $lib
-	done
-        ${RM}r "$tmpdir"
-      fi
-    fi
-
-    if test -n "$finish_cmds$finish_eval" && test -n "$libdirs"; then
-      for libdir in $libdirs; do
-	if test -n "$finish_cmds"; then
-	  # Do each command in the finish commands.
-	  func_execute_cmds "$finish_cmds" 'admincmds="$admincmds
-'"$cmd"'"'
-	fi
-	if test -n "$finish_eval"; then
-	  # Do the single finish_eval.
-	  eval cmds=\"$finish_eval\"
-	  $opt_dry_run || eval "$cmds" || func_append admincmds "
-       $cmds"
-	fi
-      done
-    fi
-
-    # Exit here if they wanted silent mode.
-    $opt_silent && exit $EXIT_SUCCESS
-
-    if test -n "$finish_cmds$finish_eval" && test -n "$libdirs"; then
-      echo "----------------------------------------------------------------------"
-      echo "Libraries have been installed in:"
-      for libdir in $libdirs; do
-	$ECHO "   $libdir"
-      done
-      echo
-      echo "If you ever happen to want to link against installed libraries"
-      echo "in a given directory, LIBDIR, you must either use libtool, and"
-      echo "specify the full pathname of the library, or use the \`-LLIBDIR'"
-      echo "flag during linking and do at least one of the following:"
-      if test -n "$shlibpath_var"; then
-	echo "   - add LIBDIR to the \`$shlibpath_var' environment variable"
-	echo "     during execution"
-      fi
-      if test -n "$runpath_var"; then
-	echo "   - add LIBDIR to the \`$runpath_var' environment variable"
-	echo "     during linking"
-      fi
-      if test -n "$hardcode_libdir_flag_spec"; then
-	libdir=LIBDIR
-	eval flag=\"$hardcode_libdir_flag_spec\"
-
-	$ECHO "   - use the \`$flag' linker flag"
-      fi
-      if test -n "$admincmds"; then
-	$ECHO "   - have your system administrator run these commands:$admincmds"
-      fi
-      if test -f /etc/ld.so.conf; then
-	echo "   - have your system administrator add LIBDIR to \`/etc/ld.so.conf'"
-      fi
-      echo
-
-      echo "See any operating system documentation about shared libraries for"
-      case $host in
-	solaris2.[6789]|solaris2.1[0-9])
-	  echo "more information, such as the ld(1), crle(1) and ld.so(8) manual"
-	  echo "pages."
-	  ;;
-	*)
-	  echo "more information, such as the ld(1) and ld.so(8) manual pages."
-	  ;;
-      esac
-      echo "----------------------------------------------------------------------"
-    fi
-    exit $EXIT_SUCCESS
-}
-
-test "$opt_mode" = finish && func_mode_finish ${1+"$@"}
-
-
-# func_mode_install arg...
-func_mode_install ()
-{
-    $opt_debug
-    # There may be an optional sh(1) argument at the beginning of
-    # install_prog (especially on Windows NT).
-    if test "$nonopt" = "$SHELL" || test "$nonopt" = /bin/sh ||
-       # Allow the use of GNU shtool's install command.
-       case $nonopt in *shtool*) :;; *) false;; esac; then
-      # Aesthetically quote it.
-      func_quote_for_eval "$nonopt"
-      install_prog="$func_quote_for_eval_result "
-      arg=$1
-      shift
-    else
-      install_prog=
-      arg=$nonopt
-    fi
-
-    # The real first argument should be the name of the installation program.
-    # Aesthetically quote it.
-    func_quote_for_eval "$arg"
-    func_append install_prog "$func_quote_for_eval_result"
-    install_shared_prog=$install_prog
-    case " $install_prog " in
-      *[\\\ /]cp\ *) install_cp=: ;;
-      *) install_cp=false ;;
-    esac
-
-    # We need to accept at least all the BSD install flags.
-    dest=
-    files=
-    opts=
-    prev=
-    install_type=
-    isdir=no
-    stripme=
-    no_mode=:
-    for arg
-    do
-      arg2=
-      if test -n "$dest"; then
-	func_append files " $dest"
-	dest=$arg
-	continue
-      fi
-
-      case $arg in
-      -d) isdir=yes ;;
-      -f)
-	if $install_cp; then :; else
-	  prev=$arg
-	fi
-	;;
-      -g | -m | -o)
-	prev=$arg
-	;;
-      -s)
-	stripme=" -s"
-	continue
-	;;
-      -*)
-	;;
-      *)
-	# If the previous option needed an argument, then skip it.
-	if test -n "$prev"; then
-	  if test "x$prev" = x-m && test -n "$install_override_mode"; then
-	    arg2=$install_override_mode
-	    no_mode=false
-	  fi
-	  prev=
-	else
-	  dest=$arg
-	  continue
-	fi
-	;;
-      esac
-
-      # Aesthetically quote the argument.
-      func_quote_for_eval "$arg"
-      func_append install_prog " $func_quote_for_eval_result"
-      if test -n "$arg2"; then
-	func_quote_for_eval "$arg2"
-      fi
-      func_append install_shared_prog " $func_quote_for_eval_result"
-    done
-
-    test -z "$install_prog" && \
-      func_fatal_help "you must specify an install program"
-
-    test -n "$prev" && \
-      func_fatal_help "the \`$prev' option requires an argument"
-
-    if test -n "$install_override_mode" && $no_mode; then
-      if $install_cp; then :; else
-	func_quote_for_eval "$install_override_mode"
-	func_append install_shared_prog " -m $func_quote_for_eval_result"
-      fi
-    fi
-
-    if test -z "$files"; then
-      if test -z "$dest"; then
-	func_fatal_help "no file or destination specified"
-      else
-	func_fatal_help "you must specify a destination"
-      fi
-    fi
-
-    # Strip any trailing slash from the destination.
-    func_stripname '' '/' "$dest"
-    dest=$func_stripname_result
-
-    # Check to see that the destination is a directory.
-    test -d "$dest" && isdir=yes
-    if test "$isdir" = yes; then
-      destdir="$dest"
-      destname=
-    else
-      func_dirname_and_basename "$dest" "" "."
-      destdir="$func_dirname_result"
-      destname="$func_basename_result"
-
-      # Not a directory, so check to see that there is only one file specified.
-      set dummy $files; shift
-      test "$#" -gt 1 && \
-	func_fatal_help "\`$dest' is not a directory"
-    fi
-    case $destdir in
-    [\\/]* | [A-Za-z]:[\\/]*) ;;
-    *)
-      for file in $files; do
-	case $file in
-	*.lo) ;;
-	*)
-	  func_fatal_help "\`$destdir' must be an absolute directory name"
-	  ;;
-	esac
-      done
-      ;;
-    esac
-
-    # This variable tells wrapper scripts just to set variables rather
-    # than running their programs.
-    libtool_install_magic="$magic"
-
-    staticlibs=
-    future_libdirs=
-    current_libdirs=
-    for file in $files; do
-
-      # Do each installation.
-      case $file in
-      *.$libext)
-	# Do the static libraries later.
-	func_append staticlibs " $file"
-	;;
-
-      *.la)
-	func_resolve_sysroot "$file"
-	file=$func_resolve_sysroot_result
-
-	# Check to see that this really is a libtool archive.
-	func_lalib_unsafe_p "$file" \
-	  || func_fatal_help "\`$file' is not a valid libtool archive"
-
-	library_names=
-	old_library=
-	relink_command=
-	func_source "$file"
-
-	# Add the libdir to current_libdirs if it is the destination.
-	if test "X$destdir" = "X$libdir"; then
-	  case "$current_libdirs " in
-	  *" $libdir "*) ;;
-	  *) func_append current_libdirs " $libdir" ;;
-	  esac
-	else
-	  # Note the libdir as a future libdir.
-	  case "$future_libdirs " in
-	  *" $libdir "*) ;;
-	  *) func_append future_libdirs " $libdir" ;;
-	  esac
-	fi
-
-	func_dirname "$file" "/" ""
-	dir="$func_dirname_result"
-	func_append dir "$objdir"
-
-	if test -n "$relink_command"; then
-	  # Determine the prefix the user has applied to our future dir.
-	  inst_prefix_dir=`$ECHO "$destdir" | $SED -e "s%$libdir\$%%"`
-
-	  # Don't allow the user to place us outside of our expected
-	  # location b/c this prevents finding dependent libraries that
-	  # are installed to the same prefix.
-	  # At present, this check doesn't affect windows .dll's that
-	  # are installed into $libdir/../bin (currently, that works fine)
-	  # but it's something to keep an eye on.
-	  test "$inst_prefix_dir" = "$destdir" && \
-	    func_fatal_error "error: cannot install \`$file' to a directory not ending in $libdir"
-
-	  if test -n "$inst_prefix_dir"; then
-	    # Stick the inst_prefix_dir data into the link command.
-	    relink_command=`$ECHO "$relink_command" | $SED "s%@inst_prefix_dir@%-inst-prefix-dir $inst_prefix_dir%"`
-	  else
-	    relink_command=`$ECHO "$relink_command" | $SED "s%@inst_prefix_dir@%%"`
-	  fi
-
-	  func_warning "relinking \`$file'"
-	  func_show_eval "$relink_command" \
-	    'func_fatal_error "error: relink \`$file'\'' with the above command before installing it"'
-	fi
-
-	# See the names of the shared library.
-	set dummy $library_names; shift
-	if test -n "$1"; then
-	  realname="$1"
-	  shift
-
-	  srcname="$realname"
-	  test -n "$relink_command" && srcname="$realname"T
-
-	  # Install the shared library and build the symlinks.
-	  func_show_eval "$install_shared_prog $dir/$srcname $destdir/$realname" \
-	      'exit $?'
-	  tstripme="$stripme"
-	  case $host_os in
-	  cygwin* | mingw* | pw32* | cegcc*)
-	    case $realname in
-	    *.dll.a)
-	      tstripme=""
-	      ;;
-	    esac
-	    ;;
-	  esac
-	  if test -n "$tstripme" && test -n "$striplib"; then
-	    func_show_eval "$striplib $destdir/$realname" 'exit $?'
-	  fi
-
-	  if test "$#" -gt 0; then
-	    # Delete the old symlinks, and create new ones.
-	    # Try `ln -sf' first, because the `ln' binary might depend on
-	    # the symlink we replace!  Solaris /bin/ln does not understand -f,
-	    # so we also need to try rm && ln -s.
-	    for linkname
-	    do
-	      test "$linkname" != "$realname" \
-		&& func_show_eval "(cd $destdir && { $LN_S -f $realname $linkname || { $RM $linkname && $LN_S $realname $linkname; }; })"
-	    done
-	  fi
-
-	  # Do each command in the postinstall commands.
-	  lib="$destdir/$realname"
-	  func_execute_cmds "$postinstall_cmds" 'exit $?'
-	fi
-
-	# Install the pseudo-library for information purposes.
-	func_basename "$file"
-	name="$func_basename_result"
-	instname="$dir/$name"i
-	func_show_eval "$install_prog $instname $destdir/$name" 'exit $?'
-
-	# Maybe install the static library, too.
-	test -n "$old_library" && func_append staticlibs " $dir/$old_library"
-	;;
-
-      *.lo)
-	# Install (i.e. copy) a libtool object.
-
-	# Figure out destination file name, if it wasn't already specified.
-	if test -n "$destname"; then
-	  destfile="$destdir/$destname"
-	else
-	  func_basename "$file"
-	  destfile="$func_basename_result"
-	  destfile="$destdir/$destfile"
-	fi
-
-	# Deduce the name of the destination old-style object file.
-	case $destfile in
-	*.lo)
-	  func_lo2o "$destfile"
-	  staticdest=$func_lo2o_result
-	  ;;
-	*.$objext)
-	  staticdest="$destfile"
-	  destfile=
-	  ;;
-	*)
-	  func_fatal_help "cannot copy a libtool object to \`$destfile'"
-	  ;;
-	esac
-
-	# Install the libtool object if requested.
-	test -n "$destfile" && \
-	  func_show_eval "$install_prog $file $destfile" 'exit $?'
-
-	# Install the old object if enabled.
-	if test "$build_old_libs" = yes; then
-	  # Deduce the name of the old-style object file.
-	  func_lo2o "$file"
-	  staticobj=$func_lo2o_result
-	  func_show_eval "$install_prog \$staticobj \$staticdest" 'exit $?'
-	fi
-	exit $EXIT_SUCCESS
-	;;
-
-      *)
-	# Figure out destination file name, if it wasn't already specified.
-	if test -n "$destname"; then
-	  destfile="$destdir/$destname"
-	else
-	  func_basename "$file"
-	  destfile="$func_basename_result"
-	  destfile="$destdir/$destfile"
-	fi
-
-	# If the file is missing, and there is a .exe on the end, strip it
-	# because it is most likely a libtool script we actually want to
-	# install
-	stripped_ext=""
-	case $file in
-	  *.exe)
-	    if test ! -f "$file"; then
-	      func_stripname '' '.exe' "$file"
-	      file=$func_stripname_result
-	      stripped_ext=".exe"
-	    fi
-	    ;;
-	esac
-
-	# Do a test to see if this is really a libtool program.
-	case $host in
-	*cygwin* | *mingw*)
-	    if func_ltwrapper_executable_p "$file"; then
-	      func_ltwrapper_scriptname "$file"
-	      wrapper=$func_ltwrapper_scriptname_result
-	    else
-	      func_stripname '' '.exe' "$file"
-	      wrapper=$func_stripname_result
-	    fi
-	    ;;
-	*)
-	    wrapper=$file
-	    ;;
-	esac
-	if func_ltwrapper_script_p "$wrapper"; then
-	  notinst_deplibs=
-	  relink_command=
-
-	  func_source "$wrapper"
-
-	  # Check the variables that should have been set.
-	  test -z "$generated_by_libtool_version" && \
-	    func_fatal_error "invalid libtool wrapper script \`$wrapper'"
-
-	  finalize=yes
-	  for lib in $notinst_deplibs; do
-	    # Check to see that each library is installed.
-	    libdir=
-	    if test -f "$lib"; then
-	      func_source "$lib"
-	    fi
-	    libfile="$libdir/"`$ECHO "$lib" | $SED 's%^.*/%%g'` ### testsuite: skip nested quoting test
-	    if test -n "$libdir" && test ! -f "$libfile"; then
-	      func_warning "\`$lib' has not been installed in \`$libdir'"
-	      finalize=no
-	    fi
-	  done
-
-	  relink_command=
-	  func_source "$wrapper"
-
-	  outputname=
-	  if test "$fast_install" = no && test -n "$relink_command"; then
-	    $opt_dry_run || {
-	      if test "$finalize" = yes; then
-	        tmpdir=`func_mktempdir`
-		func_basename "$file$stripped_ext"
-		file="$func_basename_result"
-	        outputname="$tmpdir/$file"
-	        # Replace the output file specification.
-	        relink_command=`$ECHO "$relink_command" | $SED 's%@OUTPUT@%'"$outputname"'%g'`
-
-	        $opt_silent || {
-	          func_quote_for_expand "$relink_command"
-		  eval "func_echo $func_quote_for_expand_result"
-	        }
-	        if eval "$relink_command"; then :
-	          else
-		  func_error "error: relink \`$file' with the above command before installing it"
-		  $opt_dry_run || ${RM}r "$tmpdir"
-		  continue
-	        fi
-	        file="$outputname"
-	      else
-	        func_warning "cannot relink \`$file'"
-	      fi
-	    }
-	  else
-	    # Install the binary that we compiled earlier.
-	    file=`$ECHO "$file$stripped_ext" | $SED "s%\([^/]*\)$%$objdir/\1%"`
-	  fi
-	fi
-
-	# remove .exe since cygwin /usr/bin/install will append another
-	# one anyway
-	case $install_prog,$host in
-	*/usr/bin/install*,*cygwin*)
-	  case $file:$destfile in
-	  *.exe:*.exe)
-	    # this is ok
-	    ;;
-	  *.exe:*)
-	    destfile=$destfile.exe
-	    ;;
-	  *:*.exe)
-	    func_stripname '' '.exe' "$destfile"
-	    destfile=$func_stripname_result
-	    ;;
-	  esac
-	  ;;
-	esac
-	func_show_eval "$install_prog\$stripme \$file \$destfile" 'exit $?'
-	$opt_dry_run || if test -n "$outputname"; then
-	  ${RM}r "$tmpdir"
-	fi
-	;;
-      esac
-    done
-
-    for file in $staticlibs; do
-      func_basename "$file"
-      name="$func_basename_result"
-
-      # Set up the ranlib parameters.
-      oldlib="$destdir/$name"
-      func_to_tool_file "$oldlib" func_convert_file_msys_to_w32
-      tool_oldlib=$func_to_tool_file_result
-
-      func_show_eval "$install_prog \$file \$oldlib" 'exit $?'
-
-      if test -n "$stripme" && test -n "$old_striplib"; then
-	func_show_eval "$old_striplib $tool_oldlib" 'exit $?'
-      fi
-
-      # Do each command in the postinstall commands.
-      func_execute_cmds "$old_postinstall_cmds" 'exit $?'
-    done
-
-    test -n "$future_libdirs" && \
-      func_warning "remember to run \`$progname --finish$future_libdirs'"
-
-    if test -n "$current_libdirs"; then
-      # Maybe just do a dry run.
-      $opt_dry_run && current_libdirs=" -n$current_libdirs"
-      exec_cmd='$SHELL $progpath $preserve_args --finish$current_libdirs'
-    else
-      exit $EXIT_SUCCESS
-    fi
-}
-
-test "$opt_mode" = install && func_mode_install ${1+"$@"}
-
-
-# func_generate_dlsyms outputname originator pic_p
-# Extract symbols from dlprefiles and create ${outputname}S.o with
-# a dlpreopen symbol table.
-func_generate_dlsyms ()
-{
-    $opt_debug
-    my_outputname="$1"
-    my_originator="$2"
-    my_pic_p="${3-no}"
-    my_prefix=`$ECHO "$my_originator" | sed 's%[^a-zA-Z0-9]%_%g'`
-    my_dlsyms=
-
-    if test -n "$dlfiles$dlprefiles" || test "$dlself" != no; then
-      if test -n "$NM" && test -n "$global_symbol_pipe"; then
-	my_dlsyms="${my_outputname}S.c"
-      else
-	func_error "not configured to extract global symbols from dlpreopened files"
-      fi
-    fi
-
-    if test -n "$my_dlsyms"; then
-      case $my_dlsyms in
-      "") ;;
-      *.c)
-	# Discover the nlist of each of the dlfiles.
-	nlist="$output_objdir/${my_outputname}.nm"
-
-	func_show_eval "$RM $nlist ${nlist}S ${nlist}T"
-
-	# Parse the name list into a source file.
-	func_verbose "creating $output_objdir/$my_dlsyms"
-
-	$opt_dry_run || $ECHO > "$output_objdir/$my_dlsyms" "\
-/* $my_dlsyms - symbol resolution table for \`$my_outputname' dlsym emulation. */
-/* Generated by $PROGRAM (GNU $PACKAGE$TIMESTAMP) $VERSION */
-
-#ifdef __cplusplus
-extern \"C\" {
-#endif
-
-#if defined(__GNUC__) && (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 4)) || (__GNUC__ > 4))
-#pragma GCC diagnostic ignored \"-Wstrict-prototypes\"
-#endif
-
-/* Keep this code in sync between libtool.m4, ltmain, lt_system.h, and tests.  */
-#if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE)
-/* DATA imports from DLLs on WIN32 con't be const, because runtime
-   relocations are performed -- see ld's documentation on pseudo-relocs.  */
-# define LT_DLSYM_CONST
-#elif defined(__osf__)
-/* This system does not cope well with relocations in const data.  */
-# define LT_DLSYM_CONST
-#else
-# define LT_DLSYM_CONST const
-#endif
-
-/* External symbol declarations for the compiler. */\
-"
-
-	if test "$dlself" = yes; then
-	  func_verbose "generating symbol list for \`$output'"
-
-	  $opt_dry_run || echo ': @PROGRAM@ ' > "$nlist"
-
-	  # Add our own program objects to the symbol list.
-	  progfiles=`$ECHO "$objs$old_deplibs" | $SP2NL | $SED "$lo2o" | $NL2SP`
-	  for progfile in $progfiles; do
-	    func_to_tool_file "$progfile" func_convert_file_msys_to_w32
-	    func_verbose "extracting global C symbols from \`$func_to_tool_file_result'"
-	    $opt_dry_run || eval "$NM $func_to_tool_file_result | $global_symbol_pipe >> '$nlist'"
-	  done
-
-	  if test -n "$exclude_expsyms"; then
-	    $opt_dry_run || {
-	      eval '$EGREP -v " ($exclude_expsyms)$" "$nlist" > "$nlist"T'
-	      eval '$MV "$nlist"T "$nlist"'
-	    }
-	  fi
-
-	  if test -n "$export_symbols_regex"; then
-	    $opt_dry_run || {
-	      eval '$EGREP -e "$export_symbols_regex" "$nlist" > "$nlist"T'
-	      eval '$MV "$nlist"T "$nlist"'
-	    }
-	  fi
-
-	  # Prepare the list of exported symbols
-	  if test -z "$export_symbols"; then
-	    export_symbols="$output_objdir/$outputname.exp"
-	    $opt_dry_run || {
-	      $RM $export_symbols
-	      eval "${SED} -n -e '/^: @PROGRAM@ $/d' -e 's/^.* \(.*\)$/\1/p' "'< "$nlist" > "$export_symbols"'
-	      case $host in
-	      *cygwin* | *mingw* | *cegcc* )
-                eval "echo EXPORTS "'> "$output_objdir/$outputname.def"'
-                eval 'cat "$export_symbols" >> "$output_objdir/$outputname.def"'
-	        ;;
-	      esac
-	    }
-	  else
-	    $opt_dry_run || {
-	      eval "${SED} -e 's/\([].[*^$]\)/\\\\\1/g' -e 's/^/ /' -e 's/$/$/'"' < "$export_symbols" > "$output_objdir/$outputname.exp"'
-	      eval '$GREP -f "$output_objdir/$outputname.exp" < "$nlist" > "$nlist"T'
-	      eval '$MV "$nlist"T "$nlist"'
-	      case $host in
-	        *cygwin* | *mingw* | *cegcc* )
-	          eval "echo EXPORTS "'> "$output_objdir/$outputname.def"'
-	          eval 'cat "$nlist" >> "$output_objdir/$outputname.def"'
-	          ;;
-	      esac
-	    }
-	  fi
-	fi
-
-	for dlprefile in $dlprefiles; do
-	  func_verbose "extracting global C symbols from \`$dlprefile'"
-	  func_basename "$dlprefile"
-	  name="$func_basename_result"
-          case $host in
-	    *cygwin* | *mingw* | *cegcc* )
-	      # if an import library, we need to obtain dlname
-	      if func_win32_import_lib_p "$dlprefile"; then
-	        func_tr_sh "$dlprefile"
-	        eval "curr_lafile=\$libfile_$func_tr_sh_result"
-	        dlprefile_dlbasename=""
-	        if test -n "$curr_lafile" && func_lalib_p "$curr_lafile"; then
-	          # Use subshell, to avoid clobbering current variable values
-	          dlprefile_dlname=`source "$curr_lafile" && echo "$dlname"`
-	          if test -n "$dlprefile_dlname" ; then
-	            func_basename "$dlprefile_dlname"
-	            dlprefile_dlbasename="$func_basename_result"
-	          else
-	            # no lafile. user explicitly requested -dlpreopen <import library>.
-	            $sharedlib_from_linklib_cmd "$dlprefile"
-	            dlprefile_dlbasename=$sharedlib_from_linklib_result
-	          fi
-	        fi
-	        $opt_dry_run || {
-	          if test -n "$dlprefile_dlbasename" ; then
-	            eval '$ECHO ": $dlprefile_dlbasename" >> "$nlist"'
-	          else
-	            func_warning "Could not compute DLL name from $name"
-	            eval '$ECHO ": $name " >> "$nlist"'
-	          fi
-	          func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
-	          eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe |
-	            $SED -e '/I __imp/d' -e 's/I __nm_/D /;s/_nm__//' >> '$nlist'"
-	        }
-	      else # not an import lib
-	        $opt_dry_run || {
-	          eval '$ECHO ": $name " >> "$nlist"'
-	          func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
-	          eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe >> '$nlist'"
-	        }
-	      fi
-	    ;;
-	    *)
-	      $opt_dry_run || {
-	        eval '$ECHO ": $name " >> "$nlist"'
-	        func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
-	        eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe >> '$nlist'"
-	      }
-	    ;;
-          esac
-	done
-
-	$opt_dry_run || {
-	  # Make sure we have at least an empty file.
-	  test -f "$nlist" || : > "$nlist"
-
-	  if test -n "$exclude_expsyms"; then
-	    $EGREP -v " ($exclude_expsyms)$" "$nlist" > "$nlist"T
-	    $MV "$nlist"T "$nlist"
-	  fi
-
-	  # Try sorting and uniquifying the output.
-	  if $GREP -v "^: " < "$nlist" |
-	      if sort -k 3 </dev/null >/dev/null 2>&1; then
-		sort -k 3
-	      else
-		sort +2
-	      fi |
-	      uniq > "$nlist"S; then
-	    :
-	  else
-	    $GREP -v "^: " < "$nlist" > "$nlist"S
-	  fi
-
-	  if test -f "$nlist"S; then
-	    eval "$global_symbol_to_cdecl"' < "$nlist"S >> "$output_objdir/$my_dlsyms"'
-	  else
-	    echo '/* NONE */' >> "$output_objdir/$my_dlsyms"
-	  fi
-
-	  echo >> "$output_objdir/$my_dlsyms" "\
-
-/* The mapping between symbol names and symbols.  */
-typedef struct {
-  const char *name;
-  void *address;
-} lt_dlsymlist;
-extern LT_DLSYM_CONST lt_dlsymlist
-lt_${my_prefix}_LTX_preloaded_symbols[];
-LT_DLSYM_CONST lt_dlsymlist
-lt_${my_prefix}_LTX_preloaded_symbols[] =
-{\
-  { \"$my_originator\", (void *) 0 },"
-
-	  case $need_lib_prefix in
-	  no)
-	    eval "$global_symbol_to_c_name_address" < "$nlist" >> "$output_objdir/$my_dlsyms"
-	    ;;
-	  *)
-	    eval "$global_symbol_to_c_name_address_lib_prefix" < "$nlist" >> "$output_objdir/$my_dlsyms"
-	    ;;
-	  esac
-	  echo >> "$output_objdir/$my_dlsyms" "\
-  {0, (void *) 0}
-};
-
-/* This works around a problem in FreeBSD linker */
-#ifdef FREEBSD_WORKAROUND
-static const void *lt_preloaded_setup() {
-  return lt_${my_prefix}_LTX_preloaded_symbols;
-}
-#endif
-
-#ifdef __cplusplus
-}
-#endif\
-"
-	} # !$opt_dry_run
-
-	pic_flag_for_symtable=
-	case "$compile_command " in
-	*" -static "*) ;;
-	*)
-	  case $host in
-	  # compiling the symbol table file with pic_flag works around
-	  # a FreeBSD bug that causes programs to crash when -lm is
-	  # linked before any other PIC object.  But we must not use
-	  # pic_flag when linking with -static.  The problem exists in
-	  # FreeBSD 2.2.6 and is fixed in FreeBSD 3.1.
-	  *-*-freebsd2.*|*-*-freebsd3.0*|*-*-freebsdelf3.0*)
-	    pic_flag_for_symtable=" $pic_flag -DFREEBSD_WORKAROUND" ;;
-	  *-*-hpux*)
-	    pic_flag_for_symtable=" $pic_flag"  ;;
-	  *)
-	    if test "X$my_pic_p" != Xno; then
-	      pic_flag_for_symtable=" $pic_flag"
-	    fi
-	    ;;
-	  esac
-	  ;;
-	esac
-	symtab_cflags=
-	for arg in $LTCFLAGS; do
-	  case $arg in
-	  -pie | -fpie | -fPIE) ;;
-	  *) func_append symtab_cflags " $arg" ;;
-	  esac
-	done
-
-	# Now compile the dynamic symbol file.
-	func_show_eval '(cd $output_objdir && $LTCC$symtab_cflags -c$no_builtin_flag$pic_flag_for_symtable "$my_dlsyms")' 'exit $?'
-
-	# Clean up the generated files.
-	func_show_eval '$RM "$output_objdir/$my_dlsyms" "$nlist" "${nlist}S" "${nlist}T"'
-
-	# Transform the symbol file into the correct name.
-	symfileobj="$output_objdir/${my_outputname}S.$objext"
-	case $host in
-	*cygwin* | *mingw* | *cegcc* )
-	  if test -f "$output_objdir/$my_outputname.def"; then
-	    compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$output_objdir/$my_outputname.def $symfileobj%"`
-	    finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$output_objdir/$my_outputname.def $symfileobj%"`
-	  else
-	    compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$symfileobj%"`
-	    finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$symfileobj%"`
-	  fi
-	  ;;
-	*)
-	  compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$symfileobj%"`
-	  finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$symfileobj%"`
-	  ;;
-	esac
-	;;
-      *)
-	func_fatal_error "unknown suffix for \`$my_dlsyms'"
-	;;
-      esac
-    else
-      # We keep going just in case the user didn't refer to
-      # lt_preloaded_symbols.  The linker will fail if global_symbol_pipe
-      # really was required.
-
-      # Nullify the symbol file.
-      compile_command=`$ECHO "$compile_command" | $SED "s% @SYMFILE@%%"`
-      finalize_command=`$ECHO "$finalize_command" | $SED "s% @SYMFILE@%%"`
-    fi
-}
-
-# func_win32_libid arg
-# return the library type of file 'arg'
-#
-# Need a lot of goo to handle *both* DLLs and import libs
-# Has to be a shell function in order to 'eat' the argument
-# that is supplied when $file_magic_command is called.
-# Despite the name, also deal with 64 bit binaries.
-func_win32_libid ()
-{
-  $opt_debug
-  win32_libid_type="unknown"
-  win32_fileres=`file -L $1 2>/dev/null`
-  case $win32_fileres in
-  *ar\ archive\ import\ library*) # definitely import
-    win32_libid_type="x86 archive import"
-    ;;
-  *ar\ archive*) # could be an import, or static
-    # Keep the egrep pattern in sync with the one in _LT_CHECK_MAGIC_METHOD.
-    if eval $OBJDUMP -f $1 | $SED -e '10q' 2>/dev/null |
-       $EGREP 'file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)' >/dev/null; then
-      func_to_tool_file "$1" func_convert_file_msys_to_w32
-      win32_nmres=`eval $NM -f posix -A \"$func_to_tool_file_result\" |
-	$SED -n -e '
-	    1,100{
-		/ I /{
-		    s,.*,import,
-		    p
-		    q
-		}
-	    }'`
-      case $win32_nmres in
-      import*)  win32_libid_type="x86 archive import";;
-      *)        win32_libid_type="x86 archive static";;
-      esac
-    fi
-    ;;
-  *DLL*)
-    win32_libid_type="x86 DLL"
-    ;;
-  *executable*) # but shell scripts are "executable" too...
-    case $win32_fileres in
-    *MS\ Windows\ PE\ Intel*)
-      win32_libid_type="x86 DLL"
-      ;;
-    esac
-    ;;
-  esac
-  $ECHO "$win32_libid_type"
-}
-
-# func_cygming_dll_for_implib ARG
-#
-# Platform-specific function to extract the
-# name of the DLL associated with the specified
-# import library ARG.
-# Invoked by eval'ing the libtool variable
-#    $sharedlib_from_linklib_cmd
-# Result is available in the variable
-#    $sharedlib_from_linklib_result
-func_cygming_dll_for_implib ()
-{
-  $opt_debug
-  sharedlib_from_linklib_result=`$DLLTOOL --identify-strict --identify "$1"`
-}
-
-# func_cygming_dll_for_implib_fallback_core SECTION_NAME LIBNAMEs
-#
-# The is the core of a fallback implementation of a
-# platform-specific function to extract the name of the
-# DLL associated with the specified import library LIBNAME.
-#
-# SECTION_NAME is either .idata$6 or .idata$7, depending
-# on the platform and compiler that created the implib.
-#
-# Echos the name of the DLL associated with the
-# specified import library.
-func_cygming_dll_for_implib_fallback_core ()
-{
-  $opt_debug
-  match_literal=`$ECHO "$1" | $SED "$sed_make_literal_regex"`
-  $OBJDUMP -s --section "$1" "$2" 2>/dev/null |
-    $SED '/^Contents of section '"$match_literal"':/{
-      # Place marker at beginning of archive member dllname section
-      s/.*/====MARK====/
-      p
-      d
-    }
-    # These lines can sometimes be longer than 43 characters, but
-    # are always uninteresting
-    /:[	 ]*file format pe[i]\{,1\}-/d
-    /^In archive [^:]*:/d
-    # Ensure marker is printed
-    /^====MARK====/p
-    # Remove all lines with less than 43 characters
-    /^.\{43\}/!d
-    # From remaining lines, remove first 43 characters
-    s/^.\{43\}//' |
-    $SED -n '
-      # Join marker and all lines until next marker into a single line
-      /^====MARK====/ b para
-      H
-      $ b para
-      b
-      :para
-      x
-      s/\n//g
-      # Remove the marker
-      s/^====MARK====//
-      # Remove trailing dots and whitespace
-      s/[\. \t]*$//
-      # Print
-      /./p' |
-    # we now have a list, one entry per line, of the stringified
-    # contents of the appropriate section of all members of the
-    # archive which possess that section. Heuristic: eliminate
-    # all those which have a first or second character that is
-    # a '.' (that is, objdump's representation of an unprintable
-    # character.) This should work for all archives with less than
-    # 0x302f exports -- but will fail for DLLs whose name actually
-    # begins with a literal '.' or a single character followed by
-    # a '.'.
-    #
-    # Of those that remain, print the first one.
-    $SED -e '/^\./d;/^.\./d;q'
-}
-
-# func_cygming_gnu_implib_p ARG
-# This predicate returns with zero status (TRUE) if
-# ARG is a GNU/binutils-style import library. Returns
-# with nonzero status (FALSE) otherwise.
-func_cygming_gnu_implib_p ()
-{
-  $opt_debug
-  func_to_tool_file "$1" func_convert_file_msys_to_w32
-  func_cygming_gnu_implib_tmp=`$NM "$func_to_tool_file_result" | eval "$global_symbol_pipe" | $EGREP ' (_head_[A-Za-z0-9_]+_[ad]l*|[A-Za-z0-9_]+_[ad]l*_iname)$'`
-  test -n "$func_cygming_gnu_implib_tmp"
-}
-
-# func_cygming_ms_implib_p ARG
-# This predicate returns with zero status (TRUE) if
-# ARG is an MS-style import library. Returns
-# with nonzero status (FALSE) otherwise.
-func_cygming_ms_implib_p ()
-{
-  $opt_debug
-  func_to_tool_file "$1" func_convert_file_msys_to_w32
-  func_cygming_ms_implib_tmp=`$NM "$func_to_tool_file_result" | eval "$global_symbol_pipe" | $GREP '_NULL_IMPORT_DESCRIPTOR'`
-  test -n "$func_cygming_ms_implib_tmp"
-}
-
-# func_cygming_dll_for_implib_fallback ARG
-# Platform-specific function to extract the
-# name of the DLL associated with the specified
-# import library ARG.
-#
-# This fallback implementation is for use when $DLLTOOL
-# does not support the --identify-strict option.
-# Invoked by eval'ing the libtool variable
-#    $sharedlib_from_linklib_cmd
-# Result is available in the variable
-#    $sharedlib_from_linklib_result
-func_cygming_dll_for_implib_fallback ()
-{
-  $opt_debug
-  if func_cygming_gnu_implib_p "$1" ; then
-    # binutils import library
-    sharedlib_from_linklib_result=`func_cygming_dll_for_implib_fallback_core '.idata$7' "$1"`
-  elif func_cygming_ms_implib_p "$1" ; then
-    # ms-generated import library
-    sharedlib_from_linklib_result=`func_cygming_dll_for_implib_fallback_core '.idata$6' "$1"`
-  else
-    # unknown
-    sharedlib_from_linklib_result=""
-  fi
-}
-
-
-# func_extract_an_archive dir oldlib
-func_extract_an_archive ()
-{
-    $opt_debug
-    f_ex_an_ar_dir="$1"; shift
-    f_ex_an_ar_oldlib="$1"
-    if test "$lock_old_archive_extraction" = yes; then
-      lockfile=$f_ex_an_ar_oldlib.lock
-      until $opt_dry_run || ln "$progpath" "$lockfile" 2>/dev/null; do
-	func_echo "Waiting for $lockfile to be removed"
-	sleep 2
-      done
-    fi
-    func_show_eval "(cd \$f_ex_an_ar_dir && $AR x \"\$f_ex_an_ar_oldlib\")" \
-		   'stat=$?; rm -f "$lockfile"; exit $stat'
-    if test "$lock_old_archive_extraction" = yes; then
-      $opt_dry_run || rm -f "$lockfile"
-    fi
-    if ($AR t "$f_ex_an_ar_oldlib" | sort | sort -uc >/dev/null 2>&1); then
-     :
-    else
-      func_fatal_error "object name conflicts in archive: $f_ex_an_ar_dir/$f_ex_an_ar_oldlib"
-    fi
-}
-
-
-# func_extract_archives gentop oldlib ...
-func_extract_archives ()
-{
-    $opt_debug
-    my_gentop="$1"; shift
-    my_oldlibs=${1+"$@"}
-    my_oldobjs=""
-    my_xlib=""
-    my_xabs=""
-    my_xdir=""
-
-    for my_xlib in $my_oldlibs; do
-      # Extract the objects.
-      case $my_xlib in
-	[\\/]* | [A-Za-z]:[\\/]*) my_xabs="$my_xlib" ;;
-	*) my_xabs=`pwd`"/$my_xlib" ;;
-      esac
-      func_basename "$my_xlib"
-      my_xlib="$func_basename_result"
-      my_xlib_u=$my_xlib
-      while :; do
-        case " $extracted_archives " in
-	*" $my_xlib_u "*)
-	  func_arith $extracted_serial + 1
-	  extracted_serial=$func_arith_result
-	  my_xlib_u=lt$extracted_serial-$my_xlib ;;
-	*) break ;;
-	esac
-      done
-      extracted_archives="$extracted_archives $my_xlib_u"
-      my_xdir="$my_gentop/$my_xlib_u"
-
-      func_mkdir_p "$my_xdir"
-
-      case $host in
-      *-darwin*)
-	func_verbose "Extracting $my_xabs"
-	# Do not bother doing anything if just a dry run
-	$opt_dry_run || {
-	  darwin_orig_dir=`pwd`
-	  cd $my_xdir || exit $?
-	  darwin_archive=$my_xabs
-	  darwin_curdir=`pwd`
-	  darwin_base_archive=`basename "$darwin_archive"`
-	  darwin_arches=`$LIPO -info "$darwin_archive" 2>/dev/null | $GREP Architectures 2>/dev/null || true`
-	  if test -n "$darwin_arches"; then
-	    darwin_arches=`$ECHO "$darwin_arches" | $SED -e 's/.*are://'`
-	    darwin_arch=
-	    func_verbose "$darwin_base_archive has multiple architectures $darwin_arches"
-	    for darwin_arch in  $darwin_arches ; do
-	      func_mkdir_p "unfat-$$/${darwin_base_archive}-${darwin_arch}"
-	      $LIPO -thin $darwin_arch -output "unfat-$$/${darwin_base_archive}-${darwin_arch}/${darwin_base_archive}" "${darwin_archive}"
-	      cd "unfat-$$/${darwin_base_archive}-${darwin_arch}"
-	      func_extract_an_archive "`pwd`" "${darwin_base_archive}"
-	      cd "$darwin_curdir"
-	      $RM "unfat-$$/${darwin_base_archive}-${darwin_arch}/${darwin_base_archive}"
-	    done # $darwin_arches
-            ## Okay now we've a bunch of thin objects, gotta fatten them up :)
-	    darwin_filelist=`find unfat-$$ -type f -name \*.o -print -o -name \*.lo -print | $SED -e "$basename" | sort -u`
-	    darwin_file=
-	    darwin_files=
-	    for darwin_file in $darwin_filelist; do
-	      darwin_files=`find unfat-$$ -name $darwin_file -print | sort | $NL2SP`
-	      $LIPO -create -output "$darwin_file" $darwin_files
-	    done # $darwin_filelist
-	    $RM -rf unfat-$$
-	    cd "$darwin_orig_dir"
-	  else
-	    cd $darwin_orig_dir
-	    func_extract_an_archive "$my_xdir" "$my_xabs"
-	  fi # $darwin_arches
-	} # !$opt_dry_run
-	;;
-      *)
-        func_extract_an_archive "$my_xdir" "$my_xabs"
-	;;
-      esac
-      my_oldobjs="$my_oldobjs "`find $my_xdir -name \*.$objext -print -o -name \*.lo -print | sort | $NL2SP`
-    done
-
-    func_extract_archives_result="$my_oldobjs"
-}
-
-
-# func_emit_wrapper [arg=no]
-#
-# Emit a libtool wrapper script on stdout.
-# Don't directly open a file because we may want to
-# incorporate the script contents within a cygwin/mingw
-# wrapper executable.  Must ONLY be called from within
-# func_mode_link because it depends on a number of variables
-# set therein.
-#
-# ARG is the value that the WRAPPER_SCRIPT_BELONGS_IN_OBJDIR
-# variable will take.  If 'yes', then the emitted script
-# will assume that the directory in which it is stored is
-# the $objdir directory.  This is a cygwin/mingw-specific
-# behavior.
-func_emit_wrapper ()
-{
-	func_emit_wrapper_arg1=${1-no}
-
-	$ECHO "\
-#! $SHELL
-
-# $output - temporary wrapper script for $objdir/$outputname
-# Generated by $PROGRAM (GNU $PACKAGE$TIMESTAMP) $VERSION
-#
-# The $output program cannot be directly executed until all the libtool
-# libraries that it depends on are installed.
-#
-# This wrapper script should never be moved out of the build directory.
-# If it is, it will not operate correctly.
-
-# Sed substitution that helps us do robust quoting.  It backslashifies
-# metacharacters that are still active within double-quoted strings.
-sed_quote_subst='$sed_quote_subst'
-
-# Be Bourne compatible
-if test -n \"\${ZSH_VERSION+set}\" && (emulate sh) >/dev/null 2>&1; then
-  emulate sh
-  NULLCMD=:
-  # Zsh 3.x and 4.x performs word splitting on \${1+\"\$@\"}, which
-  # is contrary to our usage.  Disable this feature.
-  alias -g '\${1+\"\$@\"}'='\"\$@\"'
-  setopt NO_GLOB_SUBST
-else
-  case \`(set -o) 2>/dev/null\` in *posix*) set -o posix;; esac
-fi
-BIN_SH=xpg4; export BIN_SH # for Tru64
-DUALCASE=1; export DUALCASE # for MKS sh
-
-# The HP-UX ksh and POSIX shell print the target directory to stdout
-# if CDPATH is set.
-(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
-
-relink_command=\"$relink_command\"
-
-# This environment variable determines our operation mode.
-if test \"\$libtool_install_magic\" = \"$magic\"; then
-  # install mode needs the following variables:
-  generated_by_libtool_version='$macro_version'
-  notinst_deplibs='$notinst_deplibs'
-else
-  # When we are sourced in execute mode, \$file and \$ECHO are already set.
-  if test \"\$libtool_execute_magic\" != \"$magic\"; then
-    file=\"\$0\""
-
-    qECHO=`$ECHO "$ECHO" | $SED "$sed_quote_subst"`
-    $ECHO "\
-
-# A function that is used when there is no print builtin or printf.
-func_fallback_echo ()
-{
-  eval 'cat <<_LTECHO_EOF
-\$1
-_LTECHO_EOF'
-}
-    ECHO=\"$qECHO\"
-  fi
-
-# Very basic option parsing. These options are (a) specific to
-# the libtool wrapper, (b) are identical between the wrapper
-# /script/ and the wrapper /executable/ which is used only on
-# windows platforms, and (c) all begin with the string "--lt-"
-# (application programs are unlikely to have options which match
-# this pattern).
-#
-# There are only two supported options: --lt-debug and
-# --lt-dump-script. There is, deliberately, no --lt-help.
-#
-# The first argument to this parsing function should be the
-# script's $0 value, followed by "$@".
-lt_option_debug=
-func_parse_lt_options ()
-{
-  lt_script_arg0=\$0
-  shift
-  for lt_opt
-  do
-    case \"\$lt_opt\" in
-    --lt-debug) lt_option_debug=1 ;;
-    --lt-dump-script)
-        lt_dump_D=\`\$ECHO \"X\$lt_script_arg0\" | $SED -e 's/^X//' -e 's%/[^/]*$%%'\`
-        test \"X\$lt_dump_D\" = \"X\$lt_script_arg0\" && lt_dump_D=.
-        lt_dump_F=\`\$ECHO \"X\$lt_script_arg0\" | $SED -e 's/^X//' -e 's%^.*/%%'\`
-        cat \"\$lt_dump_D/\$lt_dump_F\"
-        exit 0
-      ;;
-    --lt-*)
-        \$ECHO \"Unrecognized --lt- option: '\$lt_opt'\" 1>&2
-        exit 1
-      ;;
-    esac
-  done
-
-  # Print the debug banner immediately:
-  if test -n \"\$lt_option_debug\"; then
-    echo \"${outputname}:${output}:\${LINENO}: libtool wrapper (GNU $PACKAGE$TIMESTAMP) $VERSION\" 1>&2
-  fi
-}
-
-# Used when --lt-debug. Prints its arguments to stdout
-# (redirection is the responsibility of the caller)
-func_lt_dump_args ()
-{
-  lt_dump_args_N=1;
-  for lt_arg
-  do
-    \$ECHO \"${outputname}:${output}:\${LINENO}: newargv[\$lt_dump_args_N]: \$lt_arg\"
-    lt_dump_args_N=\`expr \$lt_dump_args_N + 1\`
-  done
-}
-
-# Core function for launching the target application
-func_exec_program_core ()
-{
-"
-  case $host in
-  # Backslashes separate directories on plain windows
-  *-*-mingw | *-*-os2* | *-cegcc*)
-    $ECHO "\
-      if test -n \"\$lt_option_debug\"; then
-        \$ECHO \"${outputname}:${output}:\${LINENO}: newargv[0]: \$progdir\\\\\$program\" 1>&2
-        func_lt_dump_args \${1+\"\$@\"} 1>&2
-      fi
-      exec \"\$progdir\\\\\$program\" \${1+\"\$@\"}
-"
-    ;;
-
-  *)
-    $ECHO "\
-      if test -n \"\$lt_option_debug\"; then
-        \$ECHO \"${outputname}:${output}:\${LINENO}: newargv[0]: \$progdir/\$program\" 1>&2
-        func_lt_dump_args \${1+\"\$@\"} 1>&2
-      fi
-      exec \"\$progdir/\$program\" \${1+\"\$@\"}
-"
-    ;;
-  esac
-  $ECHO "\
-      \$ECHO \"\$0: cannot exec \$program \$*\" 1>&2
-      exit 1
-}
-
-# A function to encapsulate launching the target application
-# Strips options in the --lt-* namespace from \$@ and
-# launches target application with the remaining arguments.
-func_exec_program ()
-{
-  case \" \$* \" in
-  *\\ --lt-*)
-    for lt_wr_arg
-    do
-      case \$lt_wr_arg in
-      --lt-*) ;;
-      *) set x \"\$@\" \"\$lt_wr_arg\"; shift;;
-      esac
-      shift
-    done ;;
-  esac
-  func_exec_program_core \${1+\"\$@\"}
-}
-
-  # Parse options
-  func_parse_lt_options \"\$0\" \${1+\"\$@\"}
-
-  # Find the directory that this script lives in.
-  thisdir=\`\$ECHO \"\$file\" | $SED 's%/[^/]*$%%'\`
-  test \"x\$thisdir\" = \"x\$file\" && thisdir=.
-
-  # Follow symbolic links until we get to the real thisdir.
-  file=\`ls -ld \"\$file\" | $SED -n 's/.*-> //p'\`
-  while test -n \"\$file\"; do
-    destdir=\`\$ECHO \"\$file\" | $SED 's%/[^/]*\$%%'\`
-
-    # If there was a directory component, then change thisdir.
-    if test \"x\$destdir\" != \"x\$file\"; then
-      case \"\$destdir\" in
-      [\\\\/]* | [A-Za-z]:[\\\\/]*) thisdir=\"\$destdir\" ;;
-      *) thisdir=\"\$thisdir/\$destdir\" ;;
-      esac
-    fi
-
-    file=\`\$ECHO \"\$file\" | $SED 's%^.*/%%'\`
-    file=\`ls -ld \"\$thisdir/\$file\" | $SED -n 's/.*-> //p'\`
-  done
-
-  # Usually 'no', except on cygwin/mingw when embedded into
-  # the cwrapper.
-  WRAPPER_SCRIPT_BELONGS_IN_OBJDIR=$func_emit_wrapper_arg1
-  if test \"\$WRAPPER_SCRIPT_BELONGS_IN_OBJDIR\" = \"yes\"; then
-    # special case for '.'
-    if test \"\$thisdir\" = \".\"; then
-      thisdir=\`pwd\`
-    fi
-    # remove .libs from thisdir
-    case \"\$thisdir\" in
-    *[\\\\/]$objdir ) thisdir=\`\$ECHO \"\$thisdir\" | $SED 's%[\\\\/][^\\\\/]*$%%'\` ;;
-    $objdir )   thisdir=. ;;
-    esac
-  fi
-
-  # Try to get the absolute directory name.
-  absdir=\`cd \"\$thisdir\" && pwd\`
-  test -n \"\$absdir\" && thisdir=\"\$absdir\"
-"
-
-	if test "$fast_install" = yes; then
-	  $ECHO "\
-  program=lt-'$outputname'$exeext
-  progdir=\"\$thisdir/$objdir\"
-
-  if test ! -f \"\$progdir/\$program\" ||
-     { file=\`ls -1dt \"\$progdir/\$program\" \"\$progdir/../\$program\" 2>/dev/null | ${SED} 1q\`; \\
-       test \"X\$file\" != \"X\$progdir/\$program\"; }; then
-
-    file=\"\$\$-\$program\"
-
-    if test ! -d \"\$progdir\"; then
-      $MKDIR \"\$progdir\"
-    else
-      $RM \"\$progdir/\$file\"
-    fi"
-
-	  $ECHO "\
-
-    # relink executable if necessary
-    if test -n \"\$relink_command\"; then
-      if relink_command_output=\`eval \$relink_command 2>&1\`; then :
-      else
-	$ECHO \"\$relink_command_output\" >&2
-	$RM \"\$progdir/\$file\"
-	exit 1
-      fi
-    fi
-
-    $MV \"\$progdir/\$file\" \"\$progdir/\$program\" 2>/dev/null ||
-    { $RM \"\$progdir/\$program\";
-      $MV \"\$progdir/\$file\" \"\$progdir/\$program\"; }
-    $RM \"\$progdir/\$file\"
-  fi"
-	else
-	  $ECHO "\
-  program='$outputname'
-  progdir=\"\$thisdir/$objdir\"
-"
-	fi
-
-	$ECHO "\
-
-  if test -f \"\$progdir/\$program\"; then"
-
-	# fixup the dll searchpath if we need to.
-	#
-	# Fix the DLL searchpath if we need to.  Do this before prepending
-	# to shlibpath, because on Windows, both are PATH and uninstalled
-	# libraries must come first.
-	if test -n "$dllsearchpath"; then
-	  $ECHO "\
-    # Add the dll search path components to the executable PATH
-    PATH=$dllsearchpath:\$PATH
-"
-	fi
-
-	# Export our shlibpath_var if we have one.
-	if test "$shlibpath_overrides_runpath" = yes && test -n "$shlibpath_var" && test -n "$temp_rpath"; then
-	  $ECHO "\
-    # Add our own library path to $shlibpath_var
-    $shlibpath_var=\"$temp_rpath\$$shlibpath_var\"
-
-    # Some systems cannot cope with colon-terminated $shlibpath_var
-    # The second colon is a workaround for a bug in BeOS R4 sed
-    $shlibpath_var=\`\$ECHO \"\$$shlibpath_var\" | $SED 's/::*\$//'\`
-
-    export $shlibpath_var
-"
-	fi
-
-	$ECHO "\
-    if test \"\$libtool_execute_magic\" != \"$magic\"; then
-      # Run the actual program with our arguments.
-      func_exec_program \${1+\"\$@\"}
-    fi
-  else
-    # The program doesn't exist.
-    \$ECHO \"\$0: error: \\\`\$progdir/\$program' does not exist\" 1>&2
-    \$ECHO \"This script is just a wrapper for \$program.\" 1>&2
-    \$ECHO \"See the $PACKAGE documentation for more information.\" 1>&2
-    exit 1
-  fi
-fi\
-"
-}
-
-
-# func_emit_cwrapperexe_src
-# emit the source code for a wrapper executable on stdout
-# Must ONLY be called from within func_mode_link because
-# it depends on a number of variable set therein.
-func_emit_cwrapperexe_src ()
-{
-	cat <<EOF
-
-/* $cwrappersource - temporary wrapper executable for $objdir/$outputname
-   Generated by $PROGRAM (GNU $PACKAGE$TIMESTAMP) $VERSION
-
-   The $output program cannot be directly executed until all the libtool
-   libraries that it depends on are installed.
-
-   This wrapper executable should never be moved out of the build directory.
-   If it is, it will not operate correctly.
-*/
-EOF
-	    cat <<"EOF"
-#ifdef _MSC_VER
-# define _CRT_SECURE_NO_DEPRECATE 1
-#endif
-#include <stdio.h>
-#include <stdlib.h>
-#ifdef _MSC_VER
-# include <direct.h>
-# include <process.h>
-# include <io.h>
-#else
-# include <unistd.h>
-# include <stdint.h>
-# ifdef __CYGWIN__
-#  include <io.h>
-# endif
-#endif
-#include <malloc.h>
-#include <stdarg.h>
-#include <assert.h>
-#include <string.h>
-#include <ctype.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <sys/stat.h>
-
-/* declarations of non-ANSI functions */
-#if defined(__MINGW32__)
-# ifdef __STRICT_ANSI__
-int _putenv (const char *);
-# endif
-#elif defined(__CYGWIN__)
-# ifdef __STRICT_ANSI__
-char *realpath (const char *, char *);
-int putenv (char *);
-int setenv (const char *, const char *, int);
-# endif
-/* #elif defined (other platforms) ... */
-#endif
-
-/* portability defines, excluding path handling macros */
-#if defined(_MSC_VER)
-# define setmode _setmode
-# define stat    _stat
-# define chmod   _chmod
-# define getcwd  _getcwd
-# define putenv  _putenv
-# define S_IXUSR _S_IEXEC
-# ifndef _INTPTR_T_DEFINED
-#  define _INTPTR_T_DEFINED
-#  define intptr_t int
-# endif
-#elif defined(__MINGW32__)
-# define setmode _setmode
-# define stat    _stat
-# define chmod   _chmod
-# define getcwd  _getcwd
-# define putenv  _putenv
-#elif defined(__CYGWIN__)
-# define HAVE_SETENV
-# define FOPEN_WB "wb"
-/* #elif defined (other platforms) ... */
-#endif
-
-#if defined(PATH_MAX)
-# define LT_PATHMAX PATH_MAX
-#elif defined(MAXPATHLEN)
-# define LT_PATHMAX MAXPATHLEN
-#else
-# define LT_PATHMAX 1024
-#endif
-
-#ifndef S_IXOTH
-# define S_IXOTH 0
-#endif
-#ifndef S_IXGRP
-# define S_IXGRP 0
-#endif
-
-/* path handling portability macros */
-#ifndef DIR_SEPARATOR
-# define DIR_SEPARATOR '/'
-# define PATH_SEPARATOR ':'
-#endif
-
-#if defined (_WIN32) || defined (__MSDOS__) || defined (__DJGPP__) || \
-  defined (__OS2__)
-# define HAVE_DOS_BASED_FILE_SYSTEM
-# define FOPEN_WB "wb"
-# ifndef DIR_SEPARATOR_2
-#  define DIR_SEPARATOR_2 '\\'
-# endif
-# ifndef PATH_SEPARATOR_2
-#  define PATH_SEPARATOR_2 ';'
-# endif
-#endif
-
-#ifndef DIR_SEPARATOR_2
-# define IS_DIR_SEPARATOR(ch) ((ch) == DIR_SEPARATOR)
-#else /* DIR_SEPARATOR_2 */
-# define IS_DIR_SEPARATOR(ch) \
-	(((ch) == DIR_SEPARATOR) || ((ch) == DIR_SEPARATOR_2))
-#endif /* DIR_SEPARATOR_2 */
-
-#ifndef PATH_SEPARATOR_2
-# define IS_PATH_SEPARATOR(ch) ((ch) == PATH_SEPARATOR)
-#else /* PATH_SEPARATOR_2 */
-# define IS_PATH_SEPARATOR(ch) ((ch) == PATH_SEPARATOR_2)
-#endif /* PATH_SEPARATOR_2 */
-
-#ifndef FOPEN_WB
-# define FOPEN_WB "w"
-#endif
-#ifndef _O_BINARY
-# define _O_BINARY 0
-#endif
-
-#define XMALLOC(type, num)      ((type *) xmalloc ((num) * sizeof(type)))
-#define XFREE(stale) do { \
-  if (stale) { free ((void *) stale); stale = 0; } \
-} while (0)
-
-#if defined(LT_DEBUGWRAPPER)
-static int lt_debug = 1;
-#else
-static int lt_debug = 0;
-#endif
-
-const char *program_name = "libtool-wrapper"; /* in case xstrdup fails */
-
-void *xmalloc (size_t num);
-char *xstrdup (const char *string);
-const char *base_name (const char *name);
-char *find_executable (const char *wrapper);
-char *chase_symlinks (const char *pathspec);
-int make_executable (const char *path);
-int check_executable (const char *path);
-char *strendzap (char *str, const char *pat);
-void lt_debugprintf (const char *file, int line, const char *fmt, ...);
-void lt_fatal (const char *file, int line, const char *message, ...);
-static const char *nonnull (const char *s);
-static const char *nonempty (const char *s);
-void lt_setenv (const char *name, const char *value);
-char *lt_extend_str (const char *orig_value, const char *add, int to_end);
-void lt_update_exe_path (const char *name, const char *value);
-void lt_update_lib_path (const char *name, const char *value);
-char **prepare_spawn (char **argv);
-void lt_dump_script (FILE *f);
-EOF
-
-	    cat <<EOF
-volatile const char * MAGIC_EXE = "$magic_exe";
-const char * LIB_PATH_VARNAME = "$shlibpath_var";
-EOF
-
-	    if test "$shlibpath_overrides_runpath" = yes && test -n "$shlibpath_var" && test -n "$temp_rpath"; then
-              func_to_host_path "$temp_rpath"
-	      cat <<EOF
-const char * LIB_PATH_VALUE   = "$func_to_host_path_result";
-EOF
-	    else
-	      cat <<"EOF"
-const char * LIB_PATH_VALUE   = "";
-EOF
-	    fi
-
-	    if test -n "$dllsearchpath"; then
-              func_to_host_path "$dllsearchpath:"
-	      cat <<EOF
-const char * EXE_PATH_VARNAME = "PATH";
-const char * EXE_PATH_VALUE   = "$func_to_host_path_result";
-EOF
-	    else
-	      cat <<"EOF"
-const char * EXE_PATH_VARNAME = "";
-const char * EXE_PATH_VALUE   = "";
-EOF
-	    fi
-
-	    if test "$fast_install" = yes; then
-	      cat <<EOF
-const char * TARGET_PROGRAM_NAME = "lt-$outputname"; /* hopefully, no .exe */
-EOF
-	    else
-	      cat <<EOF
-const char * TARGET_PROGRAM_NAME = "$outputname"; /* hopefully, no .exe */
-EOF
-	    fi
-
-
-	    cat <<"EOF"
-
-#define LTWRAPPER_OPTION_PREFIX         "--lt-"
-
-static const char *ltwrapper_option_prefix = LTWRAPPER_OPTION_PREFIX;
-static const char *dumpscript_opt       = LTWRAPPER_OPTION_PREFIX "dump-script";
-static const char *debug_opt            = LTWRAPPER_OPTION_PREFIX "debug";
-
-int
-main (int argc, char *argv[])
-{
-  char **newargz;
-  int  newargc;
-  char *tmp_pathspec;
-  char *actual_cwrapper_path;
-  char *actual_cwrapper_name;
-  char *target_name;
-  char *lt_argv_zero;
-  intptr_t rval = 127;
-
-  int i;
-
-  program_name = (char *) xstrdup (base_name (argv[0]));
-  newargz = XMALLOC (char *, argc + 1);
-
-  /* very simple arg parsing; don't want to rely on getopt
-   * also, copy all non cwrapper options to newargz, except
-   * argz[0], which is handled differently
-   */
-  newargc=0;
-  for (i = 1; i < argc; i++)
-    {
-      if (strcmp (argv[i], dumpscript_opt) == 0)
-	{
-EOF
-	    case "$host" in
-	      *mingw* | *cygwin* )
-		# make stdout use "unix" line endings
-		echo "          setmode(1,_O_BINARY);"
-		;;
-	      esac
-
-	    cat <<"EOF"
-	  lt_dump_script (stdout);
-	  return 0;
-	}
-      if (strcmp (argv[i], debug_opt) == 0)
-	{
-          lt_debug = 1;
-          continue;
-	}
-      if (strcmp (argv[i], ltwrapper_option_prefix) == 0)
-        {
-          /* however, if there is an option in the LTWRAPPER_OPTION_PREFIX
-             namespace, but it is not one of the ones we know about and
-             have already dealt with, above (inluding dump-script), then
-             report an error. Otherwise, targets might begin to believe
-             they are allowed to use options in the LTWRAPPER_OPTION_PREFIX
-             namespace. The first time any user complains about this, we'll
-             need to make LTWRAPPER_OPTION_PREFIX a configure-time option
-             or a configure.ac-settable value.
-           */
-          lt_fatal (__FILE__, __LINE__,
-		    "unrecognized %s option: '%s'",
-                    ltwrapper_option_prefix, argv[i]);
-        }
-      /* otherwise ... */
-      newargz[++newargc] = xstrdup (argv[i]);
-    }
-  newargz[++newargc] = NULL;
-
-EOF
-	    cat <<EOF
-  /* The GNU banner must be the first non-error debug message */
-  lt_debugprintf (__FILE__, __LINE__, "libtool wrapper (GNU $PACKAGE$TIMESTAMP) $VERSION\n");
-EOF
-	    cat <<"EOF"
-  lt_debugprintf (__FILE__, __LINE__, "(main) argv[0]: %s\n", argv[0]);
-  lt_debugprintf (__FILE__, __LINE__, "(main) program_name: %s\n", program_name);
-
-  tmp_pathspec = find_executable (argv[0]);
-  if (tmp_pathspec == NULL)
-    lt_fatal (__FILE__, __LINE__, "couldn't find %s", argv[0]);
-  lt_debugprintf (__FILE__, __LINE__,
-                  "(main) found exe (before symlink chase) at: %s\n",
-		  tmp_pathspec);
-
-  actual_cwrapper_path = chase_symlinks (tmp_pathspec);
-  lt_debugprintf (__FILE__, __LINE__,
-                  "(main) found exe (after symlink chase) at: %s\n",
-		  actual_cwrapper_path);
-  XFREE (tmp_pathspec);
-
-  actual_cwrapper_name = xstrdup (base_name (actual_cwrapper_path));
-  strendzap (actual_cwrapper_path, actual_cwrapper_name);
-
-  /* wrapper name transforms */
-  strendzap (actual_cwrapper_name, ".exe");
-  tmp_pathspec = lt_extend_str (actual_cwrapper_name, ".exe", 1);
-  XFREE (actual_cwrapper_name);
-  actual_cwrapper_name = tmp_pathspec;
-  tmp_pathspec = 0;
-
-  /* target_name transforms -- use actual target program name; might have lt- prefix */
-  target_name = xstrdup (base_name (TARGET_PROGRAM_NAME));
-  strendzap (target_name, ".exe");
-  tmp_pathspec = lt_extend_str (target_name, ".exe", 1);
-  XFREE (target_name);
-  target_name = tmp_pathspec;
-  tmp_pathspec = 0;
-
-  lt_debugprintf (__FILE__, __LINE__,
-		  "(main) libtool target name: %s\n",
-		  target_name);
-EOF
-
-	    cat <<EOF
-  newargz[0] =
-    XMALLOC (char, (strlen (actual_cwrapper_path) +
-		    strlen ("$objdir") + 1 + strlen (actual_cwrapper_name) + 1));
-  strcpy (newargz[0], actual_cwrapper_path);
-  strcat (newargz[0], "$objdir");
-  strcat (newargz[0], "/");
-EOF
-
-	    cat <<"EOF"
-  /* stop here, and copy so we don't have to do this twice */
-  tmp_pathspec = xstrdup (newargz[0]);
-
-  /* do NOT want the lt- prefix here, so use actual_cwrapper_name */
-  strcat (newargz[0], actual_cwrapper_name);
-
-  /* DO want the lt- prefix here if it exists, so use target_name */
-  lt_argv_zero = lt_extend_str (tmp_pathspec, target_name, 1);
-  XFREE (tmp_pathspec);
-  tmp_pathspec = NULL;
-EOF
-
-	    case $host_os in
-	      mingw*)
-	    cat <<"EOF"
-  {
-    char* p;
-    while ((p = strchr (newargz[0], '\\')) != NULL)
-      {
-	*p = '/';
-      }
-    while ((p = strchr (lt_argv_zero, '\\')) != NULL)
-      {
-	*p = '/';
-      }
-  }
-EOF
-	    ;;
-	    esac
-
-	    cat <<"EOF"
-  XFREE (target_name);
-  XFREE (actual_cwrapper_path);
-  XFREE (actual_cwrapper_name);
-
-  lt_setenv ("BIN_SH", "xpg4"); /* for Tru64 */
-  lt_setenv ("DUALCASE", "1");  /* for MSK sh */
-  /* Update the DLL searchpath.  EXE_PATH_VALUE ($dllsearchpath) must
-     be prepended before (that is, appear after) LIB_PATH_VALUE ($temp_rpath)
-     because on Windows, both *_VARNAMEs are PATH but uninstalled
-     libraries must come first. */
-  lt_update_exe_path (EXE_PATH_VARNAME, EXE_PATH_VALUE);
-  lt_update_lib_path (LIB_PATH_VARNAME, LIB_PATH_VALUE);
-
-  lt_debugprintf (__FILE__, __LINE__, "(main) lt_argv_zero: %s\n",
-		  nonnull (lt_argv_zero));
-  for (i = 0; i < newargc; i++)
-    {
-      lt_debugprintf (__FILE__, __LINE__, "(main) newargz[%d]: %s\n",
-		      i, nonnull (newargz[i]));
-    }
-
-EOF
-
-	    case $host_os in
-	      mingw*)
-		cat <<"EOF"
-  /* execv doesn't actually work on mingw as expected on unix */
-  newargz = prepare_spawn (newargz);
-  rval = _spawnv (_P_WAIT, lt_argv_zero, (const char * const *) newargz);
-  if (rval == -1)
-    {
-      /* failed to start process */
-      lt_debugprintf (__FILE__, __LINE__,
-		      "(main) failed to launch target \"%s\": %s\n",
-		      lt_argv_zero, nonnull (strerror (errno)));
-      return 127;
-    }
-  return rval;
-EOF
-		;;
-	      *)
-		cat <<"EOF"
-  execv (lt_argv_zero, newargz);
-  return rval; /* =127, but avoids unused variable warning */
-EOF
-		;;
-	    esac
-
-	    cat <<"EOF"
-}
-
-void *
-xmalloc (size_t num)
-{
-  void *p = (void *) malloc (num);
-  if (!p)
-    lt_fatal (__FILE__, __LINE__, "memory exhausted");
-
-  return p;
-}
-
-char *
-xstrdup (const char *string)
-{
-  return string ? strcpy ((char *) xmalloc (strlen (string) + 1),
-			  string) : NULL;
-}
-
-const char *
-base_name (const char *name)
-{
-  const char *base;
-
-#if defined (HAVE_DOS_BASED_FILE_SYSTEM)
-  /* Skip over the disk name in MSDOS pathnames. */
-  if (isalpha ((unsigned char) name[0]) && name[1] == ':')
-    name += 2;
-#endif
-
-  for (base = name; *name; name++)
-    if (IS_DIR_SEPARATOR (*name))
-      base = name + 1;
-  return base;
-}
-
-int
-check_executable (const char *path)
-{
-  struct stat st;
-
-  lt_debugprintf (__FILE__, __LINE__, "(check_executable): %s\n",
-                  nonempty (path));
-  if ((!path) || (!*path))
-    return 0;
-
-  if ((stat (path, &st) >= 0)
-      && (st.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)))
-    return 1;
-  else
-    return 0;
-}
-
-int
-make_executable (const char *path)
-{
-  int rval = 0;
-  struct stat st;
-
-  lt_debugprintf (__FILE__, __LINE__, "(make_executable): %s\n",
-                  nonempty (path));
-  if ((!path) || (!*path))
-    return 0;
-
-  if (stat (path, &st) >= 0)
-    {
-      rval = chmod (path, st.st_mode | S_IXOTH | S_IXGRP | S_IXUSR);
-    }
-  return rval;
-}
-
-/* Searches for the full path of the wrapper.  Returns
-   newly allocated full path name if found, NULL otherwise
-   Does not chase symlinks, even on platforms that support them.
-*/
-char *
-find_executable (const char *wrapper)
-{
-  int has_slash = 0;
-  const char *p;
-  const char *p_next;
-  /* static buffer for getcwd */
-  char tmp[LT_PATHMAX + 1];
-  int tmp_len;
-  char *concat_name;
-
-  lt_debugprintf (__FILE__, __LINE__, "(find_executable): %s\n",
-                  nonempty (wrapper));
-
-  if ((wrapper == NULL) || (*wrapper == '\0'))
-    return NULL;
-
-  /* Absolute path? */
-#if defined (HAVE_DOS_BASED_FILE_SYSTEM)
-  if (isalpha ((unsigned char) wrapper[0]) && wrapper[1] == ':')
-    {
-      concat_name = xstrdup (wrapper);
-      if (check_executable (concat_name))
-	return concat_name;
-      XFREE (concat_name);
-    }
-  else
-    {
-#endif
-      if (IS_DIR_SEPARATOR (wrapper[0]))
-	{
-	  concat_name = xstrdup (wrapper);
-	  if (check_executable (concat_name))
-	    return concat_name;
-	  XFREE (concat_name);
-	}
-#if defined (HAVE_DOS_BASED_FILE_SYSTEM)
-    }
-#endif
-
-  for (p = wrapper; *p; p++)
-    if (*p == '/')
-      {
-	has_slash = 1;
-	break;
-      }
-  if (!has_slash)
-    {
-      /* no slashes; search PATH */
-      const char *path = getenv ("PATH");
-      if (path != NULL)
-	{
-	  for (p = path; *p; p = p_next)
-	    {
-	      const char *q;
-	      size_t p_len;
-	      for (q = p; *q; q++)
-		if (IS_PATH_SEPARATOR (*q))
-		  break;
-	      p_len = q - p;
-	      p_next = (*q == '\0' ? q : q + 1);
-	      if (p_len == 0)
-		{
-		  /* empty path: current directory */
-		  if (getcwd (tmp, LT_PATHMAX) == NULL)
-		    lt_fatal (__FILE__, __LINE__, "getcwd failed: %s",
-                              nonnull (strerror (errno)));
-		  tmp_len = strlen (tmp);
-		  concat_name =
-		    XMALLOC (char, tmp_len + 1 + strlen (wrapper) + 1);
-		  memcpy (concat_name, tmp, tmp_len);
-		  concat_name[tmp_len] = '/';
-		  strcpy (concat_name + tmp_len + 1, wrapper);
-		}
-	      else
-		{
-		  concat_name =
-		    XMALLOC (char, p_len + 1 + strlen (wrapper) + 1);
-		  memcpy (concat_name, p, p_len);
-		  concat_name[p_len] = '/';
-		  strcpy (concat_name + p_len + 1, wrapper);
-		}
-	      if (check_executable (concat_name))
-		return concat_name;
-	      XFREE (concat_name);
-	    }
-	}
-      /* not found in PATH; assume curdir */
-    }
-  /* Relative path | not found in path: prepend cwd */
-  if (getcwd (tmp, LT_PATHMAX) == NULL)
-    lt_fatal (__FILE__, __LINE__, "getcwd failed: %s",
-              nonnull (strerror (errno)));
-  tmp_len = strlen (tmp);
-  concat_name = XMALLOC (char, tmp_len + 1 + strlen (wrapper) + 1);
-  memcpy (concat_name, tmp, tmp_len);
-  concat_name[tmp_len] = '/';
-  strcpy (concat_name + tmp_len + 1, wrapper);
-
-  if (check_executable (concat_name))
-    return concat_name;
-  XFREE (concat_name);
-  return NULL;
-}
-
-char *
-chase_symlinks (const char *pathspec)
-{
-#ifndef S_ISLNK
-  return xstrdup (pathspec);
-#else
-  char buf[LT_PATHMAX];
-  struct stat s;
-  char *tmp_pathspec = xstrdup (pathspec);
-  char *p;
-  int has_symlinks = 0;
-  while (strlen (tmp_pathspec) && !has_symlinks)
-    {
-      lt_debugprintf (__FILE__, __LINE__,
-		      "checking path component for symlinks: %s\n",
-		      tmp_pathspec);
-      if (lstat (tmp_pathspec, &s) == 0)
-	{
-	  if (S_ISLNK (s.st_mode) != 0)
-	    {
-	      has_symlinks = 1;
-	      break;
-	    }
-
-	  /* search backwards for last DIR_SEPARATOR */
-	  p = tmp_pathspec + strlen (tmp_pathspec) - 1;
-	  while ((p > tmp_pathspec) && (!IS_DIR_SEPARATOR (*p)))
-	    p--;
-	  if ((p == tmp_pathspec) && (!IS_DIR_SEPARATOR (*p)))
-	    {
-	      /* no more DIR_SEPARATORS left */
-	      break;
-	    }
-	  *p = '\0';
-	}
-      else
-	{
-	  lt_fatal (__FILE__, __LINE__,
-		    "error accessing file \"%s\": %s",
-		    tmp_pathspec, nonnull (strerror (errno)));
-	}
-    }
-  XFREE (tmp_pathspec);
-
-  if (!has_symlinks)
-    {
-      return xstrdup (pathspec);
-    }
-
-  tmp_pathspec = realpath (pathspec, buf);
-  if (tmp_pathspec == 0)
-    {
-      lt_fatal (__FILE__, __LINE__,
-		"could not follow symlinks for %s", pathspec);
-    }
-  return xstrdup (tmp_pathspec);
-#endif
-}
-
-char *
-strendzap (char *str, const char *pat)
-{
-  size_t len, patlen;
-
-  assert (str != NULL);
-  assert (pat != NULL);
-
-  len = strlen (str);
-  patlen = strlen (pat);
-
-  if (patlen <= len)
-    {
-      str += len - patlen;
-      if (strcmp (str, pat) == 0)
-	*str = '\0';
-    }
-  return str;
-}
-
-void
-lt_debugprintf (const char *file, int line, const char *fmt, ...)
-{
-  va_list args;
-  if (lt_debug)
-    {
-      (void) fprintf (stderr, "%s:%s:%d: ", program_name, file, line);
-      va_start (args, fmt);
-      (void) vfprintf (stderr, fmt, args);
-      va_end (args);
-    }
-}
-
-static void
-lt_error_core (int exit_status, const char *file,
-	       int line, const char *mode,
-	       const char *message, va_list ap)
-{
-  fprintf (stderr, "%s:%s:%d: %s: ", program_name, file, line, mode);
-  vfprintf (stderr, message, ap);
-  fprintf (stderr, ".\n");
-
-  if (exit_status >= 0)
-    exit (exit_status);
-}
-
-void
-lt_fatal (const char *file, int line, const char *message, ...)
-{
-  va_list ap;
-  va_start (ap, message);
-  lt_error_core (EXIT_FAILURE, file, line, "FATAL", message, ap);
-  va_end (ap);
-}
-
-static const char *
-nonnull (const char *s)
-{
-  return s ? s : "(null)";
-}
-
-static const char *
-nonempty (const char *s)
-{
-  return (s && !*s) ? "(empty)" : nonnull (s);
-}
-
-void
-lt_setenv (const char *name, const char *value)
-{
-  lt_debugprintf (__FILE__, __LINE__,
-		  "(lt_setenv) setting '%s' to '%s'\n",
-                  nonnull (name), nonnull (value));
-  {
-#ifdef HAVE_SETENV
-    /* always make a copy, for consistency with !HAVE_SETENV */
-    char *str = xstrdup (value);
-    setenv (name, str, 1);
-#else
-    int len = strlen (name) + 1 + strlen (value) + 1;
-    char *str = XMALLOC (char, len);
-    sprintf (str, "%s=%s", name, value);
-    if (putenv (str) != EXIT_SUCCESS)
-      {
-        XFREE (str);
-      }
-#endif
-  }
-}
-
-char *
-lt_extend_str (const char *orig_value, const char *add, int to_end)
-{
-  char *new_value;
-  if (orig_value && *orig_value)
-    {
-      int orig_value_len = strlen (orig_value);
-      int add_len = strlen (add);
-      new_value = XMALLOC (char, add_len + orig_value_len + 1);
-      if (to_end)
-        {
-          strcpy (new_value, orig_value);
-          strcpy (new_value + orig_value_len, add);
-        }
-      else
-        {
-          strcpy (new_value, add);
-          strcpy (new_value + add_len, orig_value);
-        }
-    }
-  else
-    {
-      new_value = xstrdup (add);
-    }
-  return new_value;
-}
-
-void
-lt_update_exe_path (const char *name, const char *value)
-{
-  lt_debugprintf (__FILE__, __LINE__,
-		  "(lt_update_exe_path) modifying '%s' by prepending '%s'\n",
-                  nonnull (name), nonnull (value));
-
-  if (name && *name && value && *value)
-    {
-      char *new_value = lt_extend_str (getenv (name), value, 0);
-      /* some systems can't cope with a ':'-terminated path #' */
-      int len = strlen (new_value);
-      while (((len = strlen (new_value)) > 0) && IS_PATH_SEPARATOR (new_value[len-1]))
-        {
-          new_value[len-1] = '\0';
-        }
-      lt_setenv (name, new_value);
-      XFREE (new_value);
-    }
-}
-
-void
-lt_update_lib_path (const char *name, const char *value)
-{
-  lt_debugprintf (__FILE__, __LINE__,
-		  "(lt_update_lib_path) modifying '%s' by prepending '%s'\n",
-                  nonnull (name), nonnull (value));
-
-  if (name && *name && value && *value)
-    {
-      char *new_value = lt_extend_str (getenv (name), value, 0);
-      lt_setenv (name, new_value);
-      XFREE (new_value);
-    }
-}
-
-EOF
-	    case $host_os in
-	      mingw*)
-		cat <<"EOF"
-
-/* Prepares an argument vector before calling spawn().
-   Note that spawn() does not by itself call the command interpreter
-     (getenv ("COMSPEC") != NULL ? getenv ("COMSPEC") :
-      ({ OSVERSIONINFO v; v.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
-         GetVersionEx(&v);
-         v.dwPlatformId == VER_PLATFORM_WIN32_NT;
-      }) ? "cmd.exe" : "command.com").
-   Instead it simply concatenates the arguments, separated by ' ', and calls
-   CreateProcess().  We must quote the arguments since Win32 CreateProcess()
-   interprets characters like ' ', '\t', '\\', '"' (but not '<' and '>') in a
-   special way:
-   - Space and tab are interpreted as delimiters. They are not treated as
-     delimiters if they are surrounded by double quotes: "...".
-   - Unescaped double quotes are removed from the input. Their only effect is
-     that within double quotes, space and tab are treated like normal
-     characters.
-   - Backslashes not followed by double quotes are not special.
-   - But 2*n+1 backslashes followed by a double quote become
-     n backslashes followed by a double quote (n >= 0):
-       \" -> "
-       \\\" -> \"
-       \\\\\" -> \\"
- */
-#define SHELL_SPECIAL_CHARS "\"\\ \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037"
-#define SHELL_SPACE_CHARS " \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037"
-char **
-prepare_spawn (char **argv)
-{
-  size_t argc;
-  char **new_argv;
-  size_t i;
-
-  /* Count number of arguments.  */
-  for (argc = 0; argv[argc] != NULL; argc++)
-    ;
-
-  /* Allocate new argument vector.  */
-  new_argv = XMALLOC (char *, argc + 1);
-
-  /* Put quoted arguments into the new argument vector.  */
-  for (i = 0; i < argc; i++)
-    {
-      const char *string = argv[i];
-
-      if (string[0] == '\0')
-	new_argv[i] = xstrdup ("\"\"");
-      else if (strpbrk (string, SHELL_SPECIAL_CHARS) != NULL)
-	{
-	  int quote_around = (strpbrk (string, SHELL_SPACE_CHARS) != NULL);
-	  size_t length;
-	  unsigned int backslashes;
-	  const char *s;
-	  char *quoted_string;
-	  char *p;
-
-	  length = 0;
-	  backslashes = 0;
-	  if (quote_around)
-	    length++;
-	  for (s = string; *s != '\0'; s++)
-	    {
-	      char c = *s;
-	      if (c == '"')
-		length += backslashes + 1;
-	      length++;
-	      if (c == '\\')
-		backslashes++;
-	      else
-		backslashes = 0;
-	    }
-	  if (quote_around)
-	    length += backslashes + 1;
-
-	  quoted_string = XMALLOC (char, length + 1);
-
-	  p = quoted_string;
-	  backslashes = 0;
-	  if (quote_around)
-	    *p++ = '"';
-	  for (s = string; *s != '\0'; s++)
-	    {
-	      char c = *s;
-	      if (c == '"')
-		{
-		  unsigned int j;
-		  for (j = backslashes + 1; j > 0; j--)
-		    *p++ = '\\';
-		}
-	      *p++ = c;
-	      if (c == '\\')
-		backslashes++;
-	      else
-		backslashes = 0;
-	    }
-	  if (quote_around)
-	    {
-	      unsigned int j;
-	      for (j = backslashes; j > 0; j--)
-		*p++ = '\\';
-	      *p++ = '"';
-	    }
-	  *p = '\0';
-
-	  new_argv[i] = quoted_string;
-	}
-      else
-	new_argv[i] = (char *) string;
-    }
-  new_argv[argc] = NULL;
-
-  return new_argv;
-}
-EOF
-		;;
-	    esac
-
-            cat <<"EOF"
-void lt_dump_script (FILE* f)
-{
-EOF
-	    func_emit_wrapper yes |
-	      $SED -n -e '
-s/^\(.\{79\}\)\(..*\)/\1\
-\2/
-h
-s/\([\\"]\)/\\\1/g
-s/$/\\n/
-s/\([^\n]*\).*/  fputs ("\1", f);/p
-g
-D'
-            cat <<"EOF"
-}
-EOF
-}
-# end: func_emit_cwrapperexe_src
-
-# func_win32_import_lib_p ARG
-# True if ARG is an import lib, as indicated by $file_magic_cmd
-func_win32_import_lib_p ()
-{
-    $opt_debug
-    case `eval $file_magic_cmd \"\$1\" 2>/dev/null | $SED -e 10q` in
-    *import*) : ;;
-    *) false ;;
-    esac
-}
-
-# func_mode_link arg...
-func_mode_link ()
-{
-    $opt_debug
-    case $host in
-    *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
-      # It is impossible to link a dll without this setting, and
-      # we shouldn't force the makefile maintainer to figure out
-      # which system we are compiling for in order to pass an extra
-      # flag for every libtool invocation.
-      # allow_undefined=no
-
-      # FIXME: Unfortunately, there are problems with the above when trying
-      # to make a dll which has undefined symbols, in which case not
-      # even a static library is built.  For now, we need to specify
-      # -no-undefined on the libtool link line when we can be certain
-      # that all symbols are satisfied, otherwise we get a static library.
-      allow_undefined=yes
-      ;;
-    *)
-      allow_undefined=yes
-      ;;
-    esac
-    libtool_args=$nonopt
-    base_compile="$nonopt $@"
-    compile_command=$nonopt
-    finalize_command=$nonopt
-
-    compile_rpath=
-    finalize_rpath=
-    compile_shlibpath=
-    finalize_shlibpath=
-    convenience=
-    old_convenience=
-    deplibs=
-    old_deplibs=
-    compiler_flags=
-    linker_flags=
-    dllsearchpath=
-    lib_search_path=`pwd`
-    inst_prefix_dir=
-    new_inherited_linker_flags=
-
-    avoid_version=no
-    bindir=
-    dlfiles=
-    dlprefiles=
-    dlself=no
-    export_dynamic=no
-    export_symbols=
-    export_symbols_regex=
-    generated=
-    libobjs=
-    ltlibs=
-    module=no
-    no_install=no
-    objs=
-    non_pic_objects=
-    precious_files_regex=
-    prefer_static_libs=no
-    preload=no
-    prev=
-    prevarg=
-    release=
-    rpath=
-    xrpath=
-    perm_rpath=
-    temp_rpath=
-    thread_safe=no
-    vinfo=
-    vinfo_number=no
-    weak_libs=
-    single_module="${wl}-single_module"
-    func_infer_tag $base_compile
-
-    # We need to know -static, to get the right output filenames.
-    for arg
-    do
-      case $arg in
-      -shared)
-	test "$build_libtool_libs" != yes && \
-	  func_fatal_configuration "can not build a shared library"
-	build_old_libs=no
-	break
-	;;
-      -all-static | -static | -static-libtool-libs)
-	case $arg in
-	-all-static)
-	  if test "$build_libtool_libs" = yes && test -z "$link_static_flag"; then
-	    func_warning "complete static linking is impossible in this configuration"
-	  fi
-	  if test -n "$link_static_flag"; then
-	    dlopen_self=$dlopen_self_static
-	  fi
-	  prefer_static_libs=yes
-	  ;;
-	-static)
-	  if test -z "$pic_flag" && test -n "$link_static_flag"; then
-	    dlopen_self=$dlopen_self_static
-	  fi
-	  prefer_static_libs=built
-	  ;;
-	-static-libtool-libs)
-	  if test -z "$pic_flag" && test -n "$link_static_flag"; then
-	    dlopen_self=$dlopen_self_static
-	  fi
-	  prefer_static_libs=yes
-	  ;;
-	esac
-	build_libtool_libs=no
-	build_old_libs=yes
-	break
-	;;
-      esac
-    done
-
-    # See if our shared archives depend on static archives.
-    test -n "$old_archive_from_new_cmds" && build_old_libs=yes
-
-    # Go through the arguments, transforming them on the way.
-    while test "$#" -gt 0; do
-      arg="$1"
-      shift
-      func_quote_for_eval "$arg"
-      qarg=$func_quote_for_eval_unquoted_result
-      func_append libtool_args " $func_quote_for_eval_result"
-
-      # If the previous option needs an argument, assign it.
-      if test -n "$prev"; then
-	case $prev in
-	output)
-	  func_append compile_command " @OUTPUT@"
-	  func_append finalize_command " @OUTPUT@"
-	  ;;
-	esac
-
-	case $prev in
-	bindir)
-	  bindir="$arg"
-	  prev=
-	  continue
-	  ;;
-	dlfiles|dlprefiles)
-	  if test "$preload" = no; then
-	    # Add the symbol object into the linking commands.
-	    func_append compile_command " @SYMFILE@"
-	    func_append finalize_command " @SYMFILE@"
-	    preload=yes
-	  fi
-	  case $arg in
-	  *.la | *.lo) ;;  # We handle these cases below.
-	  force)
-	    if test "$dlself" = no; then
-	      dlself=needless
-	      export_dynamic=yes
-	    fi
-	    prev=
-	    continue
-	    ;;
-	  self)
-	    if test "$prev" = dlprefiles; then
-	      dlself=yes
-	    elif test "$prev" = dlfiles && test "$dlopen_self" != yes; then
-	      dlself=yes
-	    else
-	      dlself=needless
-	      export_dynamic=yes
-	    fi
-	    prev=
-	    continue
-	    ;;
-	  *)
-	    if test "$prev" = dlfiles; then
-	      func_append dlfiles " $arg"
-	    else
-	      func_append dlprefiles " $arg"
-	    fi
-	    prev=
-	    continue
-	    ;;
-	  esac
-	  ;;
-	expsyms)
-	  export_symbols="$arg"
-	  test -f "$arg" \
-	    || func_fatal_error "symbol file \`$arg' does not exist"
-	  prev=
-	  continue
-	  ;;
-	expsyms_regex)
-	  export_symbols_regex="$arg"
-	  prev=
-	  continue
-	  ;;
-	framework)
-	  case $host in
-	    *-*-darwin*)
-	      case "$deplibs " in
-		*" $qarg.ltframework "*) ;;
-		*) func_append deplibs " $qarg.ltframework" # this is fixed later
-		   ;;
-	      esac
-	      ;;
-	  esac
-	  prev=
-	  continue
-	  ;;
-	inst_prefix)
-	  inst_prefix_dir="$arg"
-	  prev=
-	  continue
-	  ;;
-	objectlist)
-	  if test -f "$arg"; then
-	    save_arg=$arg
-	    moreargs=
-	    for fil in `cat "$save_arg"`
-	    do
-#	      func_append moreargs " $fil"
-	      arg=$fil
-	      # A libtool-controlled object.
-
-	      # Check to see that this really is a libtool object.
-	      if func_lalib_unsafe_p "$arg"; then
-		pic_object=
-		non_pic_object=
-
-		# Read the .lo file
-		func_source "$arg"
-
-		if test -z "$pic_object" ||
-		   test -z "$non_pic_object" ||
-		   test "$pic_object" = none &&
-		   test "$non_pic_object" = none; then
-		  func_fatal_error "cannot find name of object for \`$arg'"
-		fi
-
-		# Extract subdirectory from the argument.
-		func_dirname "$arg" "/" ""
-		xdir="$func_dirname_result"
-
-		if test "$pic_object" != none; then
-		  # Prepend the subdirectory the object is found in.
-		  pic_object="$xdir$pic_object"
-
-		  if test "$prev" = dlfiles; then
-		    if test "$build_libtool_libs" = yes && test "$dlopen_support" = yes; then
-		      func_append dlfiles " $pic_object"
-		      prev=
-		      continue
-		    else
-		      # If libtool objects are unsupported, then we need to preload.
-		      prev=dlprefiles
-		    fi
-		  fi
-
-		  # CHECK ME:  I think I busted this.  -Ossama
-		  if test "$prev" = dlprefiles; then
-		    # Preload the old-style object.
-		    func_append dlprefiles " $pic_object"
-		    prev=
-		  fi
-
-		  # A PIC object.
-		  func_append libobjs " $pic_object"
-		  arg="$pic_object"
-		fi
-
-		# Non-PIC object.
-		if test "$non_pic_object" != none; then
-		  # Prepend the subdirectory the object is found in.
-		  non_pic_object="$xdir$non_pic_object"
-
-		  # A standard non-PIC object
-		  func_append non_pic_objects " $non_pic_object"
-		  if test -z "$pic_object" || test "$pic_object" = none ; then
-		    arg="$non_pic_object"
-		  fi
-		else
-		  # If the PIC object exists, use it instead.
-		  # $xdir was prepended to $pic_object above.
-		  non_pic_object="$pic_object"
-		  func_append non_pic_objects " $non_pic_object"
-		fi
-	      else
-		# Only an error if not doing a dry-run.
-		if $opt_dry_run; then
-		  # Extract subdirectory from the argument.
-		  func_dirname "$arg" "/" ""
-		  xdir="$func_dirname_result"
-
-		  func_lo2o "$arg"
-		  pic_object=$xdir$objdir/$func_lo2o_result
-		  non_pic_object=$xdir$func_lo2o_result
-		  func_append libobjs " $pic_object"
-		  func_append non_pic_objects " $non_pic_object"
-	        else
-		  func_fatal_error "\`$arg' is not a valid libtool object"
-		fi
-	      fi
-	    done
-	  else
-	    func_fatal_error "link input file \`$arg' does not exist"
-	  fi
-	  arg=$save_arg
-	  prev=
-	  continue
-	  ;;
-	precious_regex)
-	  precious_files_regex="$arg"
-	  prev=
-	  continue
-	  ;;
-	release)
-	  release="-$arg"
-	  prev=
-	  continue
-	  ;;
-	rpath | xrpath)
-	  # We need an absolute path.
-	  case $arg in
-	  [\\/]* | [A-Za-z]:[\\/]*) ;;
-	  *)
-	    func_fatal_error "only absolute run-paths are allowed"
-	    ;;
-	  esac
-	  if test "$prev" = rpath; then
-	    case "$rpath " in
-	    *" $arg "*) ;;
-	    *) func_append rpath " $arg" ;;
-	    esac
-	  else
-	    case "$xrpath " in
-	    *" $arg "*) ;;
-	    *) func_append xrpath " $arg" ;;
-	    esac
-	  fi
-	  prev=
-	  continue
-	  ;;
-	shrext)
-	  shrext_cmds="$arg"
-	  prev=
-	  continue
-	  ;;
-	weak)
-	  func_append weak_libs " $arg"
-	  prev=
-	  continue
-	  ;;
-	xcclinker)
-	  func_append linker_flags " $qarg"
-	  func_append compiler_flags " $qarg"
-	  prev=
-	  func_append compile_command " $qarg"
-	  func_append finalize_command " $qarg"
-	  continue
-	  ;;
-	xcompiler)
-	  func_append compiler_flags " $qarg"
-	  prev=
-	  func_append compile_command " $qarg"
-	  func_append finalize_command " $qarg"
-	  continue
-	  ;;
-	xlinker)
-	  func_append linker_flags " $qarg"
-	  func_append compiler_flags " $wl$qarg"
-	  prev=
-	  func_append compile_command " $wl$qarg"
-	  func_append finalize_command " $wl$qarg"
-	  continue
-	  ;;
-	*)
-	  eval "$prev=\"\$arg\""
-	  prev=
-	  continue
-	  ;;
-	esac
-      fi # test -n "$prev"
-
-      prevarg="$arg"
-
-      case $arg in
-      -all-static)
-	if test -n "$link_static_flag"; then
-	  # See comment for -static flag below, for more details.
-	  func_append compile_command " $link_static_flag"
-	  func_append finalize_command " $link_static_flag"
-	fi
-	continue
-	;;
-
-      -allow-undefined)
-	# FIXME: remove this flag sometime in the future.
-	func_fatal_error "\`-allow-undefined' must not be used because it is the default"
-	;;
-
-      -avoid-version)
-	avoid_version=yes
-	continue
-	;;
-
-      -bindir)
-	prev=bindir
-	continue
-	;;
-
-      -dlopen)
-	prev=dlfiles
-	continue
-	;;
-
-      -dlpreopen)
-	prev=dlprefiles
-	continue
-	;;
-
-      -export-dynamic)
-	export_dynamic=yes
-	continue
-	;;
-
-      -export-symbols | -export-symbols-regex)
-	if test -n "$export_symbols" || test -n "$export_symbols_regex"; then
-	  func_fatal_error "more than one -exported-symbols argument is not allowed"
-	fi
-	if test "X$arg" = "X-export-symbols"; then
-	  prev=expsyms
-	else
-	  prev=expsyms_regex
-	fi
-	continue
-	;;
-
-      -framework)
-	prev=framework
-	continue
-	;;
-
-      -inst-prefix-dir)
-	prev=inst_prefix
-	continue
-	;;
-
-      # The native IRIX linker understands -LANG:*, -LIST:* and -LNO:*
-      # so, if we see these flags be careful not to treat them like -L
-      -L[A-Z][A-Z]*:*)
-	case $with_gcc/$host in
-	no/*-*-irix* | /*-*-irix*)
-	  func_append compile_command " $arg"
-	  func_append finalize_command " $arg"
-	  ;;
-	esac
-	continue
-	;;
-
-      -L*)
-	func_stripname "-L" '' "$arg"
-	if test -z "$func_stripname_result"; then
-	  if test "$#" -gt 0; then
-	    func_fatal_error "require no space between \`-L' and \`$1'"
-	  else
-	    func_fatal_error "need path for \`-L' option"
-	  fi
-	fi
-	func_resolve_sysroot "$func_stripname_result"
-	dir=$func_resolve_sysroot_result
-	# We need an absolute path.
-	case $dir in
-	[\\/]* | [A-Za-z]:[\\/]*) ;;
-	*)
-	  absdir=`cd "$dir" && pwd`
-	  test -z "$absdir" && \
-	    func_fatal_error "cannot determine absolute directory name of \`$dir'"
-	  dir="$absdir"
-	  ;;
-	esac
-	case "$deplibs " in
-	*" -L$dir "* | *" $arg "*)
-	  # Will only happen for absolute or sysroot arguments
-	  ;;
-	*)
-	  # Preserve sysroot, but never include relative directories
-	  case $dir in
-	    [\\/]* | [A-Za-z]:[\\/]* | =*) func_append deplibs " $arg" ;;
-	    *) func_append deplibs " -L$dir" ;;
-	  esac
-	  func_append lib_search_path " $dir"
-	  ;;
-	esac
-	case $host in
-	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
-	  testbindir=`$ECHO "$dir" | $SED 's*/lib$*/bin*'`
-	  case :$dllsearchpath: in
-	  *":$dir:"*) ;;
-	  ::) dllsearchpath=$dir;;
-	  *) func_append dllsearchpath ":$dir";;
-	  esac
-	  case :$dllsearchpath: in
-	  *":$testbindir:"*) ;;
-	  ::) dllsearchpath=$testbindir;;
-	  *) func_append dllsearchpath ":$testbindir";;
-	  esac
-	  ;;
-	esac
-	continue
-	;;
-
-      -l*)
-	if test "X$arg" = "X-lc" || test "X$arg" = "X-lm"; then
-	  case $host in
-	  *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-beos* | *-cegcc* | *-*-haiku*)
-	    # These systems don't actually have a C or math library (as such)
-	    continue
-	    ;;
-	  *-*-os2*)
-	    # These systems don't actually have a C library (as such)
-	    test "X$arg" = "X-lc" && continue
-	    ;;
-	  *-*-openbsd* | *-*-freebsd* | *-*-dragonfly*)
-	    # Do not include libc due to us having libc/libc_r.
-	    test "X$arg" = "X-lc" && continue
-	    ;;
-	  *-*-rhapsody* | *-*-darwin1.[012])
-	    # Rhapsody C and math libraries are in the System framework
-	    func_append deplibs " System.ltframework"
-	    continue
-	    ;;
-	  *-*-sco3.2v5* | *-*-sco5v6*)
-	    # Causes problems with __ctype
-	    test "X$arg" = "X-lc" && continue
-	    ;;
-	  *-*-sysv4.2uw2* | *-*-sysv5* | *-*-unixware* | *-*-OpenUNIX*)
-	    # Compiler inserts libc in the correct place for threads to work
-	    test "X$arg" = "X-lc" && continue
-	    ;;
-	  esac
-	elif test "X$arg" = "X-lc_r"; then
-	 case $host in
-	 *-*-openbsd* | *-*-freebsd* | *-*-dragonfly*)
-	   # Do not include libc_r directly, use -pthread flag.
-	   continue
-	   ;;
-	 esac
-	fi
-	func_append deplibs " $arg"
-	continue
-	;;
-
-      -module)
-	module=yes
-	continue
-	;;
-
-      # Tru64 UNIX uses -model [arg] to determine the layout of C++
-      # classes, name mangling, and exception handling.
-      # Darwin uses the -arch flag to determine output architecture.
-      -model|-arch|-isysroot|--sysroot)
-	func_append compiler_flags " $arg"
-	func_append compile_command " $arg"
-	func_append finalize_command " $arg"
-	prev=xcompiler
-	continue
-	;;
-
-      -mt|-mthreads|-kthread|-Kthread|-pthread|-pthreads|--thread-safe \
-      |-threads|-fopenmp|-openmp|-mp|-xopenmp|-omp|-qsmp=*)
-	func_append compiler_flags " $arg"
-	func_append compile_command " $arg"
-	func_append finalize_command " $arg"
-	case "$new_inherited_linker_flags " in
-	    *" $arg "*) ;;
-	    * ) func_append new_inherited_linker_flags " $arg" ;;
-	esac
-	continue
-	;;
-
-      -multi_module)
-	single_module="${wl}-multi_module"
-	continue
-	;;
-
-      -no-fast-install)
-	fast_install=no
-	continue
-	;;
-
-      -no-install)
-	case $host in
-	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-darwin* | *-cegcc*)
-	  # The PATH hackery in wrapper scripts is required on Windows
-	  # and Darwin in order for the loader to find any dlls it needs.
-	  func_warning "\`-no-install' is ignored for $host"
-	  func_warning "assuming \`-no-fast-install' instead"
-	  fast_install=no
-	  ;;
-	*) no_install=yes ;;
-	esac
-	continue
-	;;
-
-      -no-undefined)
-	allow_undefined=no
-	continue
-	;;
-
-      -objectlist)
-	prev=objectlist
-	continue
-	;;
-
-      -o) prev=output ;;
-
-      -precious-files-regex)
-	prev=precious_regex
-	continue
-	;;
-
-      -release)
-	prev=release
-	continue
-	;;
-
-      -rpath)
-	prev=rpath
-	continue
-	;;
-
-      -R)
-	prev=xrpath
-	continue
-	;;
-
-      -R*)
-	func_stripname '-R' '' "$arg"
-	dir=$func_stripname_result
-	# We need an absolute path.
-	case $dir in
-	[\\/]* | [A-Za-z]:[\\/]*) ;;
-	=*)
-	  func_stripname '=' '' "$dir"
-	  dir=$lt_sysroot$func_stripname_result
-	  ;;
-	*)
-	  func_fatal_error "only absolute run-paths are allowed"
-	  ;;
-	esac
-	case "$xrpath " in
-	*" $dir "*) ;;
-	*) func_append xrpath " $dir" ;;
-	esac
-	continue
-	;;
-
-      -shared)
-	# The effects of -shared are defined in a previous loop.
-	continue
-	;;
-
-      -shrext)
-	prev=shrext
-	continue
-	;;
-
-      -static | -static-libtool-libs)
-	# The effects of -static are defined in a previous loop.
-	# We used to do the same as -all-static on platforms that
-	# didn't have a PIC flag, but the assumption that the effects
-	# would be equivalent was wrong.  It would break on at least
-	# Digital Unix and AIX.
-	continue
-	;;
-
-      -thread-safe)
-	thread_safe=yes
-	continue
-	;;
-
-      -version-info)
-	prev=vinfo
-	continue
-	;;
-
-      -version-number)
-	prev=vinfo
-	vinfo_number=yes
-	continue
-	;;
-
-      -weak)
-        prev=weak
-	continue
-	;;
-
-      -Wc,*)
-	func_stripname '-Wc,' '' "$arg"
-	args=$func_stripname_result
-	arg=
-	save_ifs="$IFS"; IFS=','
-	for flag in $args; do
-	  IFS="$save_ifs"
-          func_quote_for_eval "$flag"
-	  func_append arg " $func_quote_for_eval_result"
-	  func_append compiler_flags " $func_quote_for_eval_result"
-	done
-	IFS="$save_ifs"
-	func_stripname ' ' '' "$arg"
-	arg=$func_stripname_result
-	;;
-
-      -Wl,*)
-	func_stripname '-Wl,' '' "$arg"
-	args=$func_stripname_result
-	arg=
-	save_ifs="$IFS"; IFS=','
-	for flag in $args; do
-	  IFS="$save_ifs"
-          func_quote_for_eval "$flag"
-	  func_append arg " $wl$func_quote_for_eval_result"
-	  func_append compiler_flags " $wl$func_quote_for_eval_result"
-	  func_append linker_flags " $func_quote_for_eval_result"
-	done
-	IFS="$save_ifs"
-	func_stripname ' ' '' "$arg"
-	arg=$func_stripname_result
-	;;
-
-      -Xcompiler)
-	prev=xcompiler
-	continue
-	;;
-
-      -Xlinker)
-	prev=xlinker
-	continue
-	;;
-
-      -XCClinker)
-	prev=xcclinker
-	continue
-	;;
-
-      # -msg_* for osf cc
-      -msg_*)
-	func_quote_for_eval "$arg"
-	arg="$func_quote_for_eval_result"
-	;;
-
-      # Flags to be passed through unchanged, with rationale:
-      # -64, -mips[0-9]      enable 64-bit mode for the SGI compiler
-      # -r[0-9][0-9]*        specify processor for the SGI compiler
-      # -xarch=*, -xtarget=* enable 64-bit mode for the Sun compiler
-      # +DA*, +DD*           enable 64-bit mode for the HP compiler
-      # -q*                  compiler args for the IBM compiler
-      # -m*, -t[45]*, -txscale* architecture-specific flags for GCC
-      # -F/path              path to uninstalled frameworks, gcc on darwin
-      # -p, -pg, --coverage, -fprofile-*  profiling flags for GCC
-      # @file                GCC response files
-      # -tp=*                Portland pgcc target processor selection
-      # --sysroot=*          for sysroot support
-      # -O*, -flto*, -fwhopr*, -fuse-linker-plugin GCC link-time optimization
-      -64|-mips[0-9]|-r[0-9][0-9]*|-xarch=*|-xtarget=*|+DA*|+DD*|-q*|-m*| \
-      -t[45]*|-txscale*|-p|-pg|--coverage|-fprofile-*|-F*|@*|-tp=*|--sysroot=*| \
-      -O*|-flto*|-fwhopr*|-fuse-linker-plugin)
-        func_quote_for_eval "$arg"
-	arg="$func_quote_for_eval_result"
-        func_append compile_command " $arg"
-        func_append finalize_command " $arg"
-        func_append compiler_flags " $arg"
-        continue
-        ;;
-
-      # Some other compiler flag.
-      -* | +*)
-        func_quote_for_eval "$arg"
-	arg="$func_quote_for_eval_result"
-	;;
-
-      *.$objext)
-	# A standard object.
-	func_append objs " $arg"
-	;;
-
-      *.lo)
-	# A libtool-controlled object.
-
-	# Check to see that this really is a libtool object.
-	if func_lalib_unsafe_p "$arg"; then
-	  pic_object=
-	  non_pic_object=
-
-	  # Read the .lo file
-	  func_source "$arg"
-
-	  if test -z "$pic_object" ||
-	     test -z "$non_pic_object" ||
-	     test "$pic_object" = none &&
-	     test "$non_pic_object" = none; then
-	    func_fatal_error "cannot find name of object for \`$arg'"
-	  fi
-
-	  # Extract subdirectory from the argument.
-	  func_dirname "$arg" "/" ""
-	  xdir="$func_dirname_result"
-
-	  if test "$pic_object" != none; then
-	    # Prepend the subdirectory the object is found in.
-	    pic_object="$xdir$pic_object"
-
-	    if test "$prev" = dlfiles; then
-	      if test "$build_libtool_libs" = yes && test "$dlopen_support" = yes; then
-		func_append dlfiles " $pic_object"
-		prev=
-		continue
-	      else
-		# If libtool objects are unsupported, then we need to preload.
-		prev=dlprefiles
-	      fi
-	    fi
-
-	    # CHECK ME:  I think I busted this.  -Ossama
-	    if test "$prev" = dlprefiles; then
-	      # Preload the old-style object.
-	      func_append dlprefiles " $pic_object"
-	      prev=
-	    fi
-
-	    # A PIC object.
-	    func_append libobjs " $pic_object"
-	    arg="$pic_object"
-	  fi
-
-	  # Non-PIC object.
-	  if test "$non_pic_object" != none; then
-	    # Prepend the subdirectory the object is found in.
-	    non_pic_object="$xdir$non_pic_object"
-
-	    # A standard non-PIC object
-	    func_append non_pic_objects " $non_pic_object"
-	    if test -z "$pic_object" || test "$pic_object" = none ; then
-	      arg="$non_pic_object"
-	    fi
-	  else
-	    # If the PIC object exists, use it instead.
-	    # $xdir was prepended to $pic_object above.
-	    non_pic_object="$pic_object"
-	    func_append non_pic_objects " $non_pic_object"
-	  fi
-	else
-	  # Only an error if not doing a dry-run.
-	  if $opt_dry_run; then
-	    # Extract subdirectory from the argument.
-	    func_dirname "$arg" "/" ""
-	    xdir="$func_dirname_result"
-
-	    func_lo2o "$arg"
-	    pic_object=$xdir$objdir/$func_lo2o_result
-	    non_pic_object=$xdir$func_lo2o_result
-	    func_append libobjs " $pic_object"
-	    func_append non_pic_objects " $non_pic_object"
-	  else
-	    func_fatal_error "\`$arg' is not a valid libtool object"
-	  fi
-	fi
-	;;
-
-      *.$libext)
-	# An archive.
-	func_append deplibs " $arg"
-	func_append old_deplibs " $arg"
-	continue
-	;;
-
-      *.la)
-	# A libtool-controlled library.
-
-	func_resolve_sysroot "$arg"
-	if test "$prev" = dlfiles; then
-	  # This library was specified with -dlopen.
-	  func_append dlfiles " $func_resolve_sysroot_result"
-	  prev=
-	elif test "$prev" = dlprefiles; then
-	  # The library was specified with -dlpreopen.
-	  func_append dlprefiles " $func_resolve_sysroot_result"
-	  prev=
-	else
-	  func_append deplibs " $func_resolve_sysroot_result"
-	fi
-	continue
-	;;
-
-      # Some other compiler argument.
-      *)
-	# Unknown arguments in both finalize_command and compile_command need
-	# to be aesthetically quoted because they are evaled later.
-	func_quote_for_eval "$arg"
-	arg="$func_quote_for_eval_result"
-	;;
-      esac # arg
-
-      # Now actually substitute the argument into the commands.
-      if test -n "$arg"; then
-	func_append compile_command " $arg"
-	func_append finalize_command " $arg"
-      fi
-    done # argument parsing loop
-
-    test -n "$prev" && \
-      func_fatal_help "the \`$prevarg' option requires an argument"
-
-    if test "$export_dynamic" = yes && test -n "$export_dynamic_flag_spec"; then
-      eval arg=\"$export_dynamic_flag_spec\"
-      func_append compile_command " $arg"
-      func_append finalize_command " $arg"
-    fi
-
-    oldlibs=
-    # calculate the name of the file, without its directory
-    func_basename "$output"
-    outputname="$func_basename_result"
-    libobjs_save="$libobjs"
-
-    if test -n "$shlibpath_var"; then
-      # get the directories listed in $shlibpath_var
-      eval shlib_search_path=\`\$ECHO \"\${$shlibpath_var}\" \| \$SED \'s/:/ /g\'\`
-    else
-      shlib_search_path=
-    fi
-    eval sys_lib_search_path=\"$sys_lib_search_path_spec\"
-    eval sys_lib_dlsearch_path=\"$sys_lib_dlsearch_path_spec\"
-
-    func_dirname "$output" "/" ""
-    output_objdir="$func_dirname_result$objdir"
-    func_to_tool_file "$output_objdir/"
-    tool_output_objdir=$func_to_tool_file_result
-    # Create the object directory.
-    func_mkdir_p "$output_objdir"
-
-    # Determine the type of output
-    case $output in
-    "")
-      func_fatal_help "you must specify an output file"
-      ;;
-    *.$libext) linkmode=oldlib ;;
-    *.lo | *.$objext) linkmode=obj ;;
-    *.la) linkmode=lib ;;
-    *) linkmode=prog ;; # Anything else should be a program.
-    esac
-
-    specialdeplibs=
-
-    libs=
-    # Find all interdependent deplibs by searching for libraries
-    # that are linked more than once (e.g. -la -lb -la)
-    for deplib in $deplibs; do
-      if $opt_preserve_dup_deps ; then
-	case "$libs " in
-	*" $deplib "*) func_append specialdeplibs " $deplib" ;;
-	esac
-      fi
-      func_append libs " $deplib"
-    done
-
-    if test "$linkmode" = lib; then
-      libs="$predeps $libs $compiler_lib_search_path $postdeps"
-
-      # Compute libraries that are listed more than once in $predeps
-      # $postdeps and mark them as special (i.e., whose duplicates are
-      # not to be eliminated).
-      pre_post_deps=
-      if $opt_duplicate_compiler_generated_deps; then
-	for pre_post_dep in $predeps $postdeps; do
-	  case "$pre_post_deps " in
-	  *" $pre_post_dep "*) func_append specialdeplibs " $pre_post_deps" ;;
-	  esac
-	  func_append pre_post_deps " $pre_post_dep"
-	done
-      fi
-      pre_post_deps=
-    fi
-
-    deplibs=
-    newdependency_libs=
-    newlib_search_path=
-    need_relink=no # whether we're linking any uninstalled libtool libraries
-    notinst_deplibs= # not-installed libtool libraries
-    notinst_path= # paths that contain not-installed libtool libraries
-
-    case $linkmode in
-    lib)
-	passes="conv dlpreopen link"
-	for file in $dlfiles $dlprefiles; do
-	  case $file in
-	  *.la) ;;
-	  *)
-	    func_fatal_help "libraries can \`-dlopen' only libtool libraries: $file"
-	    ;;
-	  esac
-	done
-	;;
-    prog)
-	compile_deplibs=
-	finalize_deplibs=
-	alldeplibs=no
-	newdlfiles=
-	newdlprefiles=
-	passes="conv scan dlopen dlpreopen link"
-	;;
-    *)  passes="conv"
-	;;
-    esac
-
-    for pass in $passes; do
-      # The preopen pass in lib mode reverses $deplibs; put it back here
-      # so that -L comes before libs that need it for instance...
-      if test "$linkmode,$pass" = "lib,link"; then
-	## FIXME: Find the place where the list is rebuilt in the wrong
-	##        order, and fix it there properly
-        tmp_deplibs=
-	for deplib in $deplibs; do
-	  tmp_deplibs="$deplib $tmp_deplibs"
-	done
-	deplibs="$tmp_deplibs"
-      fi
-
-      if test "$linkmode,$pass" = "lib,link" ||
-	 test "$linkmode,$pass" = "prog,scan"; then
-	libs="$deplibs"
-	deplibs=
-      fi
-      if test "$linkmode" = prog; then
-	case $pass in
-	dlopen) libs="$dlfiles" ;;
-	dlpreopen) libs="$dlprefiles" ;;
-	link) libs="$deplibs %DEPLIBS% $dependency_libs" ;;
-	esac
-      fi
-      if test "$linkmode,$pass" = "lib,dlpreopen"; then
-	# Collect and forward deplibs of preopened libtool libs
-	for lib in $dlprefiles; do
-	  # Ignore non-libtool-libs
-	  dependency_libs=
-	  func_resolve_sysroot "$lib"
-	  case $lib in
-	  *.la)	func_source "$func_resolve_sysroot_result" ;;
-	  esac
-
-	  # Collect preopened libtool deplibs, except any this library
-	  # has declared as weak libs
-	  for deplib in $dependency_libs; do
-	    func_basename "$deplib"
-            deplib_base=$func_basename_result
-	    case " $weak_libs " in
-	    *" $deplib_base "*) ;;
-	    *) func_append deplibs " $deplib" ;;
-	    esac
-	  done
-	done
-	libs="$dlprefiles"
-      fi
-      if test "$pass" = dlopen; then
-	# Collect dlpreopened libraries
-	save_deplibs="$deplibs"
-	deplibs=
-      fi
-
-      for deplib in $libs; do
-	lib=
-	found=no
-	case $deplib in
-	-mt|-mthreads|-kthread|-Kthread|-pthread|-pthreads|--thread-safe \
-        |-threads|-fopenmp|-openmp|-mp|-xopenmp|-omp|-qsmp=*)
-	  if test "$linkmode,$pass" = "prog,link"; then
-	    compile_deplibs="$deplib $compile_deplibs"
-	    finalize_deplibs="$deplib $finalize_deplibs"
-	  else
-	    func_append compiler_flags " $deplib"
-	    if test "$linkmode" = lib ; then
-		case "$new_inherited_linker_flags " in
-		    *" $deplib "*) ;;
-		    * ) func_append new_inherited_linker_flags " $deplib" ;;
-		esac
-	    fi
-	  fi
-	  continue
-	  ;;
-	-l*)
-	  if test "$linkmode" != lib && test "$linkmode" != prog; then
-	    func_warning "\`-l' is ignored for archives/objects"
-	    continue
-	  fi
-	  func_stripname '-l' '' "$deplib"
-	  name=$func_stripname_result
-	  if test "$linkmode" = lib; then
-	    searchdirs="$newlib_search_path $lib_search_path $compiler_lib_search_dirs $sys_lib_search_path $shlib_search_path"
-	  else
-	    searchdirs="$newlib_search_path $lib_search_path $sys_lib_search_path $shlib_search_path"
-	  fi
-	  for searchdir in $searchdirs; do
-	    for search_ext in .la $std_shrext .so .a; do
-	      # Search the libtool library
-	      lib="$searchdir/lib${name}${search_ext}"
-	      if test -f "$lib"; then
-		if test "$search_ext" = ".la"; then
-		  found=yes
-		else
-		  found=no
-		fi
-		break 2
-	      fi
-	    done
-	  done
-	  if test "$found" != yes; then
-	    # deplib doesn't seem to be a libtool library
-	    if test "$linkmode,$pass" = "prog,link"; then
-	      compile_deplibs="$deplib $compile_deplibs"
-	      finalize_deplibs="$deplib $finalize_deplibs"
-	    else
-	      deplibs="$deplib $deplibs"
-	      test "$linkmode" = lib && newdependency_libs="$deplib $newdependency_libs"
-	    fi
-	    continue
-	  else # deplib is a libtool library
-	    # If $allow_libtool_libs_with_static_runtimes && $deplib is a stdlib,
-	    # We need to do some special things here, and not later.
-	    if test "X$allow_libtool_libs_with_static_runtimes" = "Xyes" ; then
-	      case " $predeps $postdeps " in
-	      *" $deplib "*)
-		if func_lalib_p "$lib"; then
-		  library_names=
-		  old_library=
-		  func_source "$lib"
-		  for l in $old_library $library_names; do
-		    ll="$l"
-		  done
-		  if test "X$ll" = "X$old_library" ; then # only static version available
-		    found=no
-		    func_dirname "$lib" "" "."
-		    ladir="$func_dirname_result"
-		    lib=$ladir/$old_library
-		    if test "$linkmode,$pass" = "prog,link"; then
-		      compile_deplibs="$deplib $compile_deplibs"
-		      finalize_deplibs="$deplib $finalize_deplibs"
-		    else
-		      deplibs="$deplib $deplibs"
-		      test "$linkmode" = lib && newdependency_libs="$deplib $newdependency_libs"
-		    fi
-		    continue
-		  fi
-		fi
-		;;
-	      *) ;;
-	      esac
-	    fi
-	  fi
-	  ;; # -l
-	*.ltframework)
-	  if test "$linkmode,$pass" = "prog,link"; then
-	    compile_deplibs="$deplib $compile_deplibs"
-	    finalize_deplibs="$deplib $finalize_deplibs"
-	  else
-	    deplibs="$deplib $deplibs"
-	    if test "$linkmode" = lib ; then
-		case "$new_inherited_linker_flags " in
-		    *" $deplib "*) ;;
-		    * ) func_append new_inherited_linker_flags " $deplib" ;;
-		esac
-	    fi
-	  fi
-	  continue
-	  ;;
-	-L*)
-	  case $linkmode in
-	  lib)
-	    deplibs="$deplib $deplibs"
-	    test "$pass" = conv && continue
-	    newdependency_libs="$deplib $newdependency_libs"
-	    func_stripname '-L' '' "$deplib"
-	    func_resolve_sysroot "$func_stripname_result"
-	    func_append newlib_search_path " $func_resolve_sysroot_result"
-	    ;;
-	  prog)
-	    if test "$pass" = conv; then
-	      deplibs="$deplib $deplibs"
-	      continue
-	    fi
-	    if test "$pass" = scan; then
-	      deplibs="$deplib $deplibs"
-	    else
-	      compile_deplibs="$deplib $compile_deplibs"
-	      finalize_deplibs="$deplib $finalize_deplibs"
-	    fi
-	    func_stripname '-L' '' "$deplib"
-	    func_resolve_sysroot "$func_stripname_result"
-	    func_append newlib_search_path " $func_resolve_sysroot_result"
-	    ;;
-	  *)
-	    func_warning "\`-L' is ignored for archives/objects"
-	    ;;
-	  esac # linkmode
-	  continue
-	  ;; # -L
-	-R*)
-	  if test "$pass" = link; then
-	    func_stripname '-R' '' "$deplib"
-	    func_resolve_sysroot "$func_stripname_result"
-	    dir=$func_resolve_sysroot_result
-	    # Make sure the xrpath contains only unique directories.
-	    case "$xrpath " in
-	    *" $dir "*) ;;
-	    *) func_append xrpath " $dir" ;;
-	    esac
-	  fi
-	  deplibs="$deplib $deplibs"
-	  continue
-	  ;;
-	*.la)
-	  func_resolve_sysroot "$deplib"
-	  lib=$func_resolve_sysroot_result
-	  ;;
-	*.$libext)
-	  if test "$pass" = conv; then
-	    deplibs="$deplib $deplibs"
-	    continue
-	  fi
-	  case $linkmode in
-	  lib)
-	    # Linking convenience modules into shared libraries is allowed,
-	    # but linking other static libraries is non-portable.
-	    case " $dlpreconveniencelibs " in
-	    *" $deplib "*) ;;
-	    *)
-	      valid_a_lib=no
-	      case $deplibs_check_method in
-		match_pattern*)
-		  set dummy $deplibs_check_method; shift
-		  match_pattern_regex=`expr "$deplibs_check_method" : "$1 \(.*\)"`
-		  if eval "\$ECHO \"$deplib\"" 2>/dev/null | $SED 10q \
-		    | $EGREP "$match_pattern_regex" > /dev/null; then
-		    valid_a_lib=yes
-		  fi
-		;;
-		pass_all)
-		  valid_a_lib=yes
-		;;
-	      esac
-	      if test "$valid_a_lib" != yes; then
-		echo
-		$ECHO "*** Warning: Trying to link with static lib archive $deplib."
-		echo "*** I have the capability to make that library automatically link in when"
-		echo "*** you link to this library.  But I can only do this if you have a"
-		echo "*** shared version of the library, which you do not appear to have"
-		echo "*** because the file extensions .$libext of this argument makes me believe"
-		echo "*** that it is just a static archive that I should not use here."
-	      else
-		echo
-		$ECHO "*** Warning: Linking the shared library $output against the"
-		$ECHO "*** static library $deplib is not portable!"
-		deplibs="$deplib $deplibs"
-	      fi
-	      ;;
-	    esac
-	    continue
-	    ;;
-	  prog)
-	    if test "$pass" != link; then
-	      deplibs="$deplib $deplibs"
-	    else
-	      compile_deplibs="$deplib $compile_deplibs"
-	      finalize_deplibs="$deplib $finalize_deplibs"
-	    fi
-	    continue
-	    ;;
-	  esac # linkmode
-	  ;; # *.$libext
-	*.lo | *.$objext)
-	  if test "$pass" = conv; then
-	    deplibs="$deplib $deplibs"
-	  elif test "$linkmode" = prog; then
-	    if test "$pass" = dlpreopen || test "$dlopen_support" != yes || test "$build_libtool_libs" = no; then
-	      # If there is no dlopen support or we're linking statically,
-	      # we need to preload.
-	      func_append newdlprefiles " $deplib"
-	      compile_deplibs="$deplib $compile_deplibs"
-	      finalize_deplibs="$deplib $finalize_deplibs"
-	    else
-	      func_append newdlfiles " $deplib"
-	    fi
-	  fi
-	  continue
-	  ;;
-	%DEPLIBS%)
-	  alldeplibs=yes
-	  continue
-	  ;;
-	esac # case $deplib
-
-	if test "$found" = yes || test -f "$lib"; then :
-	else
-	  func_fatal_error "cannot find the library \`$lib' or unhandled argument \`$deplib'"
-	fi
-
-	# Check to see that this really is a libtool archive.
-	func_lalib_unsafe_p "$lib" \
-	  || func_fatal_error "\`$lib' is not a valid libtool archive"
-
-	func_dirname "$lib" "" "."
-	ladir="$func_dirname_result"
-
-	dlname=
-	dlopen=
-	dlpreopen=
-	libdir=
-	library_names=
-	old_library=
-	inherited_linker_flags=
-	# If the library was installed with an old release of libtool,
-	# it will not redefine variables installed, or shouldnotlink
-	installed=yes
-	shouldnotlink=no
-	avoidtemprpath=
-
-
-	# Read the .la file
-	func_source "$lib"
-
-	# Convert "-framework foo" to "foo.ltframework"
-	if test -n "$inherited_linker_flags"; then
-	  tmp_inherited_linker_flags=`$ECHO "$inherited_linker_flags" | $SED 's/-framework \([^ $]*\)/\1.ltframework/g'`
-	  for tmp_inherited_linker_flag in $tmp_inherited_linker_flags; do
-	    case " $new_inherited_linker_flags " in
-	      *" $tmp_inherited_linker_flag "*) ;;
-	      *) func_append new_inherited_linker_flags " $tmp_inherited_linker_flag";;
-	    esac
-	  done
-	fi
-	dependency_libs=`$ECHO " $dependency_libs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
-	if test "$linkmode,$pass" = "lib,link" ||
-	   test "$linkmode,$pass" = "prog,scan" ||
-	   { test "$linkmode" != prog && test "$linkmode" != lib; }; then
-	  test -n "$dlopen" && func_append dlfiles " $dlopen"
-	  test -n "$dlpreopen" && func_append dlprefiles " $dlpreopen"
-	fi
-
-	if test "$pass" = conv; then
-	  # Only check for convenience libraries
-	  deplibs="$lib $deplibs"
-	  if test -z "$libdir"; then
-	    if test -z "$old_library"; then
-	      func_fatal_error "cannot find name of link library for \`$lib'"
-	    fi
-	    # It is a libtool convenience library, so add in its objects.
-	    func_append convenience " $ladir/$objdir/$old_library"
-	    func_append old_convenience " $ladir/$objdir/$old_library"
-	  elif test "$linkmode" != prog && test "$linkmode" != lib; then
-	    func_fatal_error "\`$lib' is not a convenience library"
-	  fi
-	  tmp_libs=
-	  for deplib in $dependency_libs; do
-	    deplibs="$deplib $deplibs"
-	    if $opt_preserve_dup_deps ; then
-	      case "$tmp_libs " in
-	      *" $deplib "*) func_append specialdeplibs " $deplib" ;;
-	      esac
-	    fi
-	    func_append tmp_libs " $deplib"
-	  done
-	  continue
-	fi # $pass = conv
-
-
-	# Get the name of the library we link against.
-	linklib=
-	if test -n "$old_library" &&
-	   { test "$prefer_static_libs" = yes ||
-	     test "$prefer_static_libs,$installed" = "built,no"; }; then
-	  linklib=$old_library
-	else
-	  for l in $old_library $library_names; do
-	    linklib="$l"
-	  done
-	fi
-	if test -z "$linklib"; then
-	  func_fatal_error "cannot find name of link library for \`$lib'"
-	fi
-
-	# This library was specified with -dlopen.
-	if test "$pass" = dlopen; then
-	  if test -z "$libdir"; then
-	    func_fatal_error "cannot -dlopen a convenience library: \`$lib'"
-	  fi
-	  if test -z "$dlname" ||
-	     test "$dlopen_support" != yes ||
-	     test "$build_libtool_libs" = no; then
-	    # If there is no dlname, no dlopen support or we're linking
-	    # statically, we need to preload.  We also need to preload any
-	    # dependent libraries so libltdl's deplib preloader doesn't
-	    # bomb out in the load deplibs phase.
-	    func_append dlprefiles " $lib $dependency_libs"
-	  else
-	    func_append newdlfiles " $lib"
-	  fi
-	  continue
-	fi # $pass = dlopen
-
-	# We need an absolute path.
-	case $ladir in
-	[\\/]* | [A-Za-z]:[\\/]*) abs_ladir="$ladir" ;;
-	*)
-	  abs_ladir=`cd "$ladir" && pwd`
-	  if test -z "$abs_ladir"; then
-	    func_warning "cannot determine absolute directory name of \`$ladir'"
-	    func_warning "passing it literally to the linker, although it might fail"
-	    abs_ladir="$ladir"
-	  fi
-	  ;;
-	esac
-	func_basename "$lib"
-	laname="$func_basename_result"
-
-	# Find the relevant object directory and library name.
-	if test "X$installed" = Xyes; then
-	  if test ! -f "$lt_sysroot$libdir/$linklib" && test -f "$abs_ladir/$linklib"; then
-	    func_warning "library \`$lib' was moved."
-	    dir="$ladir"
-	    absdir="$abs_ladir"
-	    libdir="$abs_ladir"
-	  else
-	    dir="$lt_sysroot$libdir"
-	    absdir="$lt_sysroot$libdir"
-	  fi
-	  test "X$hardcode_automatic" = Xyes && avoidtemprpath=yes
-	else
-	  if test ! -f "$ladir/$objdir/$linklib" && test -f "$abs_ladir/$linklib"; then
-	    dir="$ladir"
-	    absdir="$abs_ladir"
-	    # Remove this search path later
-	    func_append notinst_path " $abs_ladir"
-	  else
-	    dir="$ladir/$objdir"
-	    absdir="$abs_ladir/$objdir"
-	    # Remove this search path later
-	    func_append notinst_path " $abs_ladir"
-	  fi
-	fi # $installed = yes
-	func_stripname 'lib' '.la' "$laname"
-	name=$func_stripname_result
-
-	# This library was specified with -dlpreopen.
-	if test "$pass" = dlpreopen; then
-	  if test -z "$libdir" && test "$linkmode" = prog; then
-	    func_fatal_error "only libraries may -dlpreopen a convenience library: \`$lib'"
-	  fi
-	  case "$host" in
-	    # special handling for platforms with PE-DLLs.
-	    *cygwin* | *mingw* | *cegcc* )
-	      # Linker will automatically link against shared library if both
-	      # static and shared are present.  Therefore, ensure we extract
-	      # symbols from the import library if a shared library is present
-	      # (otherwise, the dlopen module name will be incorrect).  We do
-	      # this by putting the import library name into $newdlprefiles.
-	      # We recover the dlopen module name by 'saving' the la file
-	      # name in a special purpose variable, and (later) extracting the
-	      # dlname from the la file.
-	      if test -n "$dlname"; then
-	        func_tr_sh "$dir/$linklib"
-	        eval "libfile_$func_tr_sh_result=\$abs_ladir/\$laname"
-	        func_append newdlprefiles " $dir/$linklib"
-	      else
-	        func_append newdlprefiles " $dir/$old_library"
-	        # Keep a list of preopened convenience libraries to check
-	        # that they are being used correctly in the link pass.
-	        test -z "$libdir" && \
-	          func_append dlpreconveniencelibs " $dir/$old_library"
-	      fi
-	    ;;
-	    * )
-	      # Prefer using a static library (so that no silly _DYNAMIC symbols
-	      # are required to link).
-	      if test -n "$old_library"; then
-	        func_append newdlprefiles " $dir/$old_library"
-	        # Keep a list of preopened convenience libraries to check
-	        # that they are being used correctly in the link pass.
-	        test -z "$libdir" && \
-	          func_append dlpreconveniencelibs " $dir/$old_library"
-	      # Otherwise, use the dlname, so that lt_dlopen finds it.
-	      elif test -n "$dlname"; then
-	        func_append newdlprefiles " $dir/$dlname"
-	      else
-	        func_append newdlprefiles " $dir/$linklib"
-	      fi
-	    ;;
-	  esac
-	fi # $pass = dlpreopen
-
-	if test -z "$libdir"; then
-	  # Link the convenience library
-	  if test "$linkmode" = lib; then
-	    deplibs="$dir/$old_library $deplibs"
-	  elif test "$linkmode,$pass" = "prog,link"; then
-	    compile_deplibs="$dir/$old_library $compile_deplibs"
-	    finalize_deplibs="$dir/$old_library $finalize_deplibs"
-	  else
-	    deplibs="$lib $deplibs" # used for prog,scan pass
-	  fi
-	  continue
-	fi
-
-
-	if test "$linkmode" = prog && test "$pass" != link; then
-	  func_append newlib_search_path " $ladir"
-	  deplibs="$lib $deplibs"
-
-	  linkalldeplibs=no
-	  if test "$link_all_deplibs" != no || test -z "$library_names" ||
-	     test "$build_libtool_libs" = no; then
-	    linkalldeplibs=yes
-	  fi
-
-	  tmp_libs=
-	  for deplib in $dependency_libs; do
-	    case $deplib in
-	    -L*) func_stripname '-L' '' "$deplib"
-	         func_resolve_sysroot "$func_stripname_result"
-	         func_append newlib_search_path " $func_resolve_sysroot_result"
-		 ;;
-	    esac
-	    # Need to link against all dependency_libs?
-	    if test "$linkalldeplibs" = yes; then
-	      deplibs="$deplib $deplibs"
-	    else
-	      # Need to hardcode shared library paths
-	      # or/and link against static libraries
-	      newdependency_libs="$deplib $newdependency_libs"
-	    fi
-	    if $opt_preserve_dup_deps ; then
-	      case "$tmp_libs " in
-	      *" $deplib "*) func_append specialdeplibs " $deplib" ;;
-	      esac
-	    fi
-	    func_append tmp_libs " $deplib"
-	  done # for deplib
-	  continue
-	fi # $linkmode = prog...
-
-	if test "$linkmode,$pass" = "prog,link"; then
-	  if test -n "$library_names" &&
-	     { { test "$prefer_static_libs" = no ||
-	         test "$prefer_static_libs,$installed" = "built,yes"; } ||
-	       test -z "$old_library"; }; then
-	    # We need to hardcode the library path
-	    if test -n "$shlibpath_var" && test -z "$avoidtemprpath" ; then
-	      # Make sure the rpath contains only unique directories.
-	      case "$temp_rpath:" in
-	      *"$absdir:"*) ;;
-	      *) func_append temp_rpath "$absdir:" ;;
-	      esac
-	    fi
-
-	    # Hardcode the library path.
-	    # Skip directories that are in the system default run-time
-	    # search path.
-	    case " $sys_lib_dlsearch_path " in
-	    *" $absdir "*) ;;
-	    *)
-	      case "$compile_rpath " in
-	      *" $absdir "*) ;;
-	      *) func_append compile_rpath " $absdir" ;;
-	      esac
-	      ;;
-	    esac
-	    case " $sys_lib_dlsearch_path " in
-	    *" $libdir "*) ;;
-	    *)
-	      case "$finalize_rpath " in
-	      *" $libdir "*) ;;
-	      *) func_append finalize_rpath " $libdir" ;;
-	      esac
-	      ;;
-	    esac
-	  fi # $linkmode,$pass = prog,link...
-
-	  if test "$alldeplibs" = yes &&
-	     { test "$deplibs_check_method" = pass_all ||
-	       { test "$build_libtool_libs" = yes &&
-		 test -n "$library_names"; }; }; then
-	    # We only need to search for static libraries
-	    continue
-	  fi
-	fi
-
-	link_static=no # Whether the deplib will be linked statically
-	use_static_libs=$prefer_static_libs
-	if test "$use_static_libs" = built && test "$installed" = yes; then
-	  use_static_libs=no
-	fi
-	if test -n "$library_names" &&
-	   { test "$use_static_libs" = no || test -z "$old_library"; }; then
-	  case $host in
-	  *cygwin* | *mingw* | *cegcc*)
-	      # No point in relinking DLLs because paths are not encoded
-	      func_append notinst_deplibs " $lib"
-	      need_relink=no
-	    ;;
-	  *)
-	    if test "$installed" = no; then
-	      func_append notinst_deplibs " $lib"
-	      need_relink=yes
-	    fi
-	    ;;
-	  esac
-	  # This is a shared library
-
-	  # Warn about portability, can't link against -module's on some
-	  # systems (darwin).  Don't bleat about dlopened modules though!
-	  dlopenmodule=""
-	  for dlpremoduletest in $dlprefiles; do
-	    if test "X$dlpremoduletest" = "X$lib"; then
-	      dlopenmodule="$dlpremoduletest"
-	      break
-	    fi
-	  done
-	  if test -z "$dlopenmodule" && test "$shouldnotlink" = yes && test "$pass" = link; then
-	    echo
-	    if test "$linkmode" = prog; then
-	      $ECHO "*** Warning: Linking the executable $output against the loadable module"
-	    else
-	      $ECHO "*** Warning: Linking the shared library $output against the loadable module"
-	    fi
-	    $ECHO "*** $linklib is not portable!"
-	  fi
-	  if test "$linkmode" = lib &&
-	     test "$hardcode_into_libs" = yes; then
-	    # Hardcode the library path.
-	    # Skip directories that are in the system default run-time
-	    # search path.
-	    case " $sys_lib_dlsearch_path " in
-	    *" $absdir "*) ;;
-	    *)
-	      case "$compile_rpath " in
-	      *" $absdir "*) ;;
-	      *) func_append compile_rpath " $absdir" ;;
-	      esac
-	      ;;
-	    esac
-	    case " $sys_lib_dlsearch_path " in
-	    *" $libdir "*) ;;
-	    *)
-	      case "$finalize_rpath " in
-	      *" $libdir "*) ;;
-	      *) func_append finalize_rpath " $libdir" ;;
-	      esac
-	      ;;
-	    esac
-	  fi
-
-	  if test -n "$old_archive_from_expsyms_cmds"; then
-	    # figure out the soname
-	    set dummy $library_names
-	    shift
-	    realname="$1"
-	    shift
-	    libname=`eval "\\$ECHO \"$libname_spec\""`
-	    # use dlname if we got it. it's perfectly good, no?
-	    if test -n "$dlname"; then
-	      soname="$dlname"
-	    elif test -n "$soname_spec"; then
-	      # bleh windows
-	      case $host in
-	      *cygwin* | mingw* | *cegcc*)
-	        func_arith $current - $age
-		major=$func_arith_result
-		versuffix="-$major"
-		;;
-	      esac
-	      eval soname=\"$soname_spec\"
-	    else
-	      soname="$realname"
-	    fi
-
-	    # Make a new name for the extract_expsyms_cmds to use
-	    soroot="$soname"
-	    func_basename "$soroot"
-	    soname="$func_basename_result"
-	    func_stripname 'lib' '.dll' "$soname"
-	    newlib=libimp-$func_stripname_result.a
-
-	    # If the library has no export list, then create one now
-	    if test -f "$output_objdir/$soname-def"; then :
-	    else
-	      func_verbose "extracting exported symbol list from \`$soname'"
-	      func_execute_cmds "$extract_expsyms_cmds" 'exit $?'
-	    fi
-
-	    # Create $newlib
-	    if test -f "$output_objdir/$newlib"; then :; else
-	      func_verbose "generating import library for \`$soname'"
-	      func_execute_cmds "$old_archive_from_expsyms_cmds" 'exit $?'
-	    fi
-	    # make sure the library variables are pointing to the new library
-	    dir=$output_objdir
-	    linklib=$newlib
-	  fi # test -n "$old_archive_from_expsyms_cmds"
-
-	  if test "$linkmode" = prog || test "$opt_mode" != relink; then
-	    add_shlibpath=
-	    add_dir=
-	    add=
-	    lib_linked=yes
-	    case $hardcode_action in
-	    immediate | unsupported)
-	      if test "$hardcode_direct" = no; then
-		add="$dir/$linklib"
-		case $host in
-		  *-*-sco3.2v5.0.[024]*) add_dir="-L$dir" ;;
-		  *-*-sysv4*uw2*) add_dir="-L$dir" ;;
-		  *-*-sysv5OpenUNIX* | *-*-sysv5UnixWare7.[01].[10]* | \
-		    *-*-unixware7*) add_dir="-L$dir" ;;
-		  *-*-darwin* )
-		    # if the lib is a (non-dlopened) module then we can not
-		    # link against it, someone is ignoring the earlier warnings
-		    if /usr/bin/file -L $add 2> /dev/null |
-			 $GREP ": [^:]* bundle" >/dev/null ; then
-		      if test "X$dlopenmodule" != "X$lib"; then
-			$ECHO "*** Warning: lib $linklib is a module, not a shared library"
-			if test -z "$old_library" ; then
-			  echo
-			  echo "*** And there doesn't seem to be a static archive available"
-			  echo "*** The link will probably fail, sorry"
-			else
-			  add="$dir/$old_library"
-			fi
-		      elif test -n "$old_library"; then
-			add="$dir/$old_library"
-		      fi
-		    fi
-		esac
-	      elif test "$hardcode_minus_L" = no; then
-		case $host in
-		*-*-sunos*) add_shlibpath="$dir" ;;
-		esac
-		add_dir="-L$dir"
-		add="-l$name"
-	      elif test "$hardcode_shlibpath_var" = no; then
-		add_shlibpath="$dir"
-		add="-l$name"
-	      else
-		lib_linked=no
-	      fi
-	      ;;
-	    relink)
-	      if test "$hardcode_direct" = yes &&
-	         test "$hardcode_direct_absolute" = no; then
-		add="$dir/$linklib"
-	      elif test "$hardcode_minus_L" = yes; then
-		add_dir="-L$absdir"
-		# Try looking first in the location we're being installed to.
-		if test -n "$inst_prefix_dir"; then
-		  case $libdir in
-		    [\\/]*)
-		      func_append add_dir " -L$inst_prefix_dir$libdir"
-		      ;;
-		  esac
-		fi
-		add="-l$name"
-	      elif test "$hardcode_shlibpath_var" = yes; then
-		add_shlibpath="$dir"
-		add="-l$name"
-	      else
-		lib_linked=no
-	      fi
-	      ;;
-	    *) lib_linked=no ;;
-	    esac
-
-	    if test "$lib_linked" != yes; then
-	      func_fatal_configuration "unsupported hardcode properties"
-	    fi
-
-	    if test -n "$add_shlibpath"; then
-	      case :$compile_shlibpath: in
-	      *":$add_shlibpath:"*) ;;
-	      *) func_append compile_shlibpath "$add_shlibpath:" ;;
-	      esac
-	    fi
-	    if test "$linkmode" = prog; then
-	      test -n "$add_dir" && compile_deplibs="$add_dir $compile_deplibs"
-	      test -n "$add" && compile_deplibs="$add $compile_deplibs"
-	    else
-	      test -n "$add_dir" && deplibs="$add_dir $deplibs"
-	      test -n "$add" && deplibs="$add $deplibs"
-	      if test "$hardcode_direct" != yes &&
-		 test "$hardcode_minus_L" != yes &&
-		 test "$hardcode_shlibpath_var" = yes; then
-		case :$finalize_shlibpath: in
-		*":$libdir:"*) ;;
-		*) func_append finalize_shlibpath "$libdir:" ;;
-		esac
-	      fi
-	    fi
-	  fi
-
-	  if test "$linkmode" = prog || test "$opt_mode" = relink; then
-	    add_shlibpath=
-	    add_dir=
-	    add=
-	    # Finalize command for both is simple: just hardcode it.
-	    if test "$hardcode_direct" = yes &&
-	       test "$hardcode_direct_absolute" = no; then
-	      add="$libdir/$linklib"
-	    elif test "$hardcode_minus_L" = yes; then
-	      add_dir="-L$libdir"
-	      add="-l$name"
-	    elif test "$hardcode_shlibpath_var" = yes; then
-	      case :$finalize_shlibpath: in
-	      *":$libdir:"*) ;;
-	      *) func_append finalize_shlibpath "$libdir:" ;;
-	      esac
-	      add="-l$name"
-	    elif test "$hardcode_automatic" = yes; then
-	      if test -n "$inst_prefix_dir" &&
-		 test -f "$inst_prefix_dir$libdir/$linklib" ; then
-		add="$inst_prefix_dir$libdir/$linklib"
-	      else
-		add="$libdir/$linklib"
-	      fi
-	    else
-	      # We cannot seem to hardcode it, guess we'll fake it.
-	      add_dir="-L$libdir"
-	      # Try looking first in the location we're being installed to.
-	      if test -n "$inst_prefix_dir"; then
-		case $libdir in
-		  [\\/]*)
-		    func_append add_dir " -L$inst_prefix_dir$libdir"
-		    ;;
-		esac
-	      fi
-	      add="-l$name"
-	    fi
-
-	    if test "$linkmode" = prog; then
-	      test -n "$add_dir" && finalize_deplibs="$add_dir $finalize_deplibs"
-	      test -n "$add" && finalize_deplibs="$add $finalize_deplibs"
-	    else
-	      test -n "$add_dir" && deplibs="$add_dir $deplibs"
-	      test -n "$add" && deplibs="$add $deplibs"
-	    fi
-	  fi
-	elif test "$linkmode" = prog; then
-	  # Here we assume that one of hardcode_direct or hardcode_minus_L
-	  # is not unsupported.  This is valid on all known static and
-	  # shared platforms.
-	  if test "$hardcode_direct" != unsupported; then
-	    test -n "$old_library" && linklib="$old_library"
-	    compile_deplibs="$dir/$linklib $compile_deplibs"
-	    finalize_deplibs="$dir/$linklib $finalize_deplibs"
-	  else
-	    compile_deplibs="-l$name -L$dir $compile_deplibs"
-	    finalize_deplibs="-l$name -L$dir $finalize_deplibs"
-	  fi
-	elif test "$build_libtool_libs" = yes; then
-	  # Not a shared library
-	  if test "$deplibs_check_method" != pass_all; then
-	    # We're trying link a shared library against a static one
-	    # but the system doesn't support it.
-
-	    # Just print a warning and add the library to dependency_libs so
-	    # that the program can be linked against the static library.
-	    echo
-	    $ECHO "*** Warning: This system can not link to static lib archive $lib."
-	    echo "*** I have the capability to make that library automatically link in when"
-	    echo "*** you link to this library.  But I can only do this if you have a"
-	    echo "*** shared version of the library, which you do not appear to have."
-	    if test "$module" = yes; then
-	      echo "*** But as you try to build a module library, libtool will still create "
-	      echo "*** a static module, that should work as long as the dlopening application"
-	      echo "*** is linked with the -dlopen flag to resolve symbols at runtime."
-	      if test -z "$global_symbol_pipe"; then
-		echo
-		echo "*** However, this would only work if libtool was able to extract symbol"
-		echo "*** lists from a program, using \`nm' or equivalent, but libtool could"
-		echo "*** not find such a program.  So, this module is probably useless."
-		echo "*** \`nm' from GNU binutils and a full rebuild may help."
-	      fi
-	      if test "$build_old_libs" = no; then
-		build_libtool_libs=module
-		build_old_libs=yes
-	      else
-		build_libtool_libs=no
-	      fi
-	    fi
-	  else
-	    deplibs="$dir/$old_library $deplibs"
-	    link_static=yes
-	  fi
-	fi # link shared/static library?
-
-	if test "$linkmode" = lib; then
-	  if test -n "$dependency_libs" &&
-	     { test "$hardcode_into_libs" != yes ||
-	       test "$build_old_libs" = yes ||
-	       test "$link_static" = yes; }; then
-	    # Extract -R from dependency_libs
-	    temp_deplibs=
-	    for libdir in $dependency_libs; do
-	      case $libdir in
-	      -R*) func_stripname '-R' '' "$libdir"
-	           temp_xrpath=$func_stripname_result
-		   case " $xrpath " in
-		   *" $temp_xrpath "*) ;;
-		   *) func_append xrpath " $temp_xrpath";;
-		   esac;;
-	      *) func_append temp_deplibs " $libdir";;
-	      esac
-	    done
-	    dependency_libs="$temp_deplibs"
-	  fi
-
-	  func_append newlib_search_path " $absdir"
-	  # Link against this library
-	  test "$link_static" = no && newdependency_libs="$abs_ladir/$laname $newdependency_libs"
-	  # ... and its dependency_libs
-	  tmp_libs=
-	  for deplib in $dependency_libs; do
-	    newdependency_libs="$deplib $newdependency_libs"
-	    case $deplib in
-              -L*) func_stripname '-L' '' "$deplib"
-                   func_resolve_sysroot "$func_stripname_result";;
-              *) func_resolve_sysroot "$deplib" ;;
-            esac
-	    if $opt_preserve_dup_deps ; then
-	      case "$tmp_libs " in
-	      *" $func_resolve_sysroot_result "*)
-                func_append specialdeplibs " $func_resolve_sysroot_result" ;;
-	      esac
-	    fi
-	    func_append tmp_libs " $func_resolve_sysroot_result"
-	  done
-
-	  if test "$link_all_deplibs" != no; then
-	    # Add the search paths of all dependency libraries
-	    for deplib in $dependency_libs; do
-	      path=
-	      case $deplib in
-	      -L*) path="$deplib" ;;
-	      *.la)
-	        func_resolve_sysroot "$deplib"
-	        deplib=$func_resolve_sysroot_result
-	        func_dirname "$deplib" "" "."
-		dir=$func_dirname_result
-		# We need an absolute path.
-		case $dir in
-		[\\/]* | [A-Za-z]:[\\/]*) absdir="$dir" ;;
-		*)
-		  absdir=`cd "$dir" && pwd`
-		  if test -z "$absdir"; then
-		    func_warning "cannot determine absolute directory name of \`$dir'"
-		    absdir="$dir"
-		  fi
-		  ;;
-		esac
-		if $GREP "^installed=no" $deplib > /dev/null; then
-		case $host in
-		*-*-darwin*)
-		  depdepl=
-		  eval deplibrary_names=`${SED} -n -e 's/^library_names=\(.*\)$/\1/p' $deplib`
-		  if test -n "$deplibrary_names" ; then
-		    for tmp in $deplibrary_names ; do
-		      depdepl=$tmp
-		    done
-		    if test -f "$absdir/$objdir/$depdepl" ; then
-		      depdepl="$absdir/$objdir/$depdepl"
-		      darwin_install_name=`${OTOOL} -L $depdepl | awk '{if (NR == 2) {print $1;exit}}'`
-                      if test -z "$darwin_install_name"; then
-                          darwin_install_name=`${OTOOL64} -L $depdepl  | awk '{if (NR == 2) {print $1;exit}}'`
-                      fi
-		      func_append compiler_flags " ${wl}-dylib_file ${wl}${darwin_install_name}:${depdepl}"
-		      func_append linker_flags " -dylib_file ${darwin_install_name}:${depdepl}"
-		      path=
-		    fi
-		  fi
-		  ;;
-		*)
-		  path="-L$absdir/$objdir"
-		  ;;
-		esac
-		else
-		  eval libdir=`${SED} -n -e 's/^libdir=\(.*\)$/\1/p' $deplib`
-		  test -z "$libdir" && \
-		    func_fatal_error "\`$deplib' is not a valid libtool archive"
-		  test "$absdir" != "$libdir" && \
-		    func_warning "\`$deplib' seems to be moved"
-
-		  path="-L$absdir"
-		fi
-		;;
-	      esac
-	      case " $deplibs " in
-	      *" $path "*) ;;
-	      *) deplibs="$path $deplibs" ;;
-	      esac
-	    done
-	  fi # link_all_deplibs != no
-	fi # linkmode = lib
-      done # for deplib in $libs
-      if test "$pass" = link; then
-	if test "$linkmode" = "prog"; then
-	  compile_deplibs="$new_inherited_linker_flags $compile_deplibs"
-	  finalize_deplibs="$new_inherited_linker_flags $finalize_deplibs"
-	else
-	  compiler_flags="$compiler_flags "`$ECHO " $new_inherited_linker_flags" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
-	fi
-      fi
-      dependency_libs="$newdependency_libs"
-      if test "$pass" = dlpreopen; then
-	# Link the dlpreopened libraries before other libraries
-	for deplib in $save_deplibs; do
-	  deplibs="$deplib $deplibs"
-	done
-      fi
-      if test "$pass" != dlopen; then
-	if test "$pass" != conv; then
-	  # Make sure lib_search_path contains only unique directories.
-	  lib_search_path=
-	  for dir in $newlib_search_path; do
-	    case "$lib_search_path " in
-	    *" $dir "*) ;;
-	    *) func_append lib_search_path " $dir" ;;
-	    esac
-	  done
-	  newlib_search_path=
-	fi
-
-	if test "$linkmode,$pass" != "prog,link"; then
-	  vars="deplibs"
-	else
-	  vars="compile_deplibs finalize_deplibs"
-	fi
-	for var in $vars dependency_libs; do
-	  # Add libraries to $var in reverse order
-	  eval tmp_libs=\"\$$var\"
-	  new_libs=
-	  for deplib in $tmp_libs; do
-	    # FIXME: Pedantically, this is the right thing to do, so
-	    #        that some nasty dependency loop isn't accidentally
-	    #        broken:
-	    #new_libs="$deplib $new_libs"
-	    # Pragmatically, this seems to cause very few problems in
-	    # practice:
-	    case $deplib in
-	    -L*) new_libs="$deplib $new_libs" ;;
-	    -R*) ;;
-	    *)
-	      # And here is the reason: when a library appears more
-	      # than once as an explicit dependence of a library, or
-	      # is implicitly linked in more than once by the
-	      # compiler, it is considered special, and multiple
-	      # occurrences thereof are not removed.  Compare this
-	      # with having the same library being listed as a
-	      # dependency of multiple other libraries: in this case,
-	      # we know (pedantically, we assume) the library does not
-	      # need to be listed more than once, so we keep only the
-	      # last copy.  This is not always right, but it is rare
-	      # enough that we require users that really mean to play
-	      # such unportable linking tricks to link the library
-	      # using -Wl,-lname, so that libtool does not consider it
-	      # for duplicate removal.
-	      case " $specialdeplibs " in
-	      *" $deplib "*) new_libs="$deplib $new_libs" ;;
-	      *)
-		case " $new_libs " in
-		*" $deplib "*) ;;
-		*) new_libs="$deplib $new_libs" ;;
-		esac
-		;;
-	      esac
-	      ;;
-	    esac
-	  done
-	  tmp_libs=
-	  for deplib in $new_libs; do
-	    case $deplib in
-	    -L*)
-	      case " $tmp_libs " in
-	      *" $deplib "*) ;;
-	      *) func_append tmp_libs " $deplib" ;;
-	      esac
-	      ;;
-	    *) func_append tmp_libs " $deplib" ;;
-	    esac
-	  done
-	  eval $var=\"$tmp_libs\"
-	done # for var
-      fi
-      # Last step: remove runtime libs from dependency_libs
-      # (they stay in deplibs)
-      tmp_libs=
-      for i in $dependency_libs ; do
-	case " $predeps $postdeps $compiler_lib_search_path " in
-	*" $i "*)
-	  i=""
-	  ;;
-	esac
-	if test -n "$i" ; then
-	  func_append tmp_libs " $i"
-	fi
-      done
-      dependency_libs=$tmp_libs
-    done # for pass
-    if test "$linkmode" = prog; then
-      dlfiles="$newdlfiles"
-    fi
-    if test "$linkmode" = prog || test "$linkmode" = lib; then
-      dlprefiles="$newdlprefiles"
-    fi
-
-    case $linkmode in
-    oldlib)
-      if test -n "$dlfiles$dlprefiles" || test "$dlself" != no; then
-	func_warning "\`-dlopen' is ignored for archives"
-      fi
-
-      case " $deplibs" in
-      *\ -l* | *\ -L*)
-	func_warning "\`-l' and \`-L' are ignored for archives" ;;
-      esac
-
-      test -n "$rpath" && \
-	func_warning "\`-rpath' is ignored for archives"
-
-      test -n "$xrpath" && \
-	func_warning "\`-R' is ignored for archives"
-
-      test -n "$vinfo" && \
-	func_warning "\`-version-info/-version-number' is ignored for archives"
-
-      test -n "$release" && \
-	func_warning "\`-release' is ignored for archives"
-
-      test -n "$export_symbols$export_symbols_regex" && \
-	func_warning "\`-export-symbols' is ignored for archives"
-
-      # Now set the variables for building old libraries.
-      build_libtool_libs=no
-      oldlibs="$output"
-      func_append objs "$old_deplibs"
-      ;;
-
-    lib)
-      # Make sure we only generate libraries of the form `libNAME.la'.
-      case $outputname in
-      lib*)
-	func_stripname 'lib' '.la' "$outputname"
-	name=$func_stripname_result
-	eval shared_ext=\"$shrext_cmds\"
-	eval libname=\"$libname_spec\"
-	;;
-      *)
-	test "$module" = no && \
-	  func_fatal_help "libtool library \`$output' must begin with \`lib'"
-
-	if test "$need_lib_prefix" != no; then
-	  # Add the "lib" prefix for modules if required
-	  func_stripname '' '.la' "$outputname"
-	  name=$func_stripname_result
-	  eval shared_ext=\"$shrext_cmds\"
-	  eval libname=\"$libname_spec\"
-	else
-	  func_stripname '' '.la' "$outputname"
-	  libname=$func_stripname_result
-	fi
-	;;
-      esac
-
-      if test -n "$objs"; then
-	if test "$deplibs_check_method" != pass_all; then
-	  func_fatal_error "cannot build libtool library \`$output' from non-libtool objects on this host:$objs"
-	else
-	  echo
-	  $ECHO "*** Warning: Linking the shared library $output against the non-libtool"
-	  $ECHO "*** objects $objs is not portable!"
-	  func_append libobjs " $objs"
-	fi
-      fi
-
-      test "$dlself" != no && \
-	func_warning "\`-dlopen self' is ignored for libtool libraries"
-
-      set dummy $rpath
-      shift
-      test "$#" -gt 1 && \
-	func_warning "ignoring multiple \`-rpath's for a libtool library"
-
-      install_libdir="$1"
-
-      oldlibs=
-      if test -z "$rpath"; then
-	if test "$build_libtool_libs" = yes; then
-	  # Building a libtool convenience library.
-	  # Some compilers have problems with a `.al' extension so
-	  # convenience libraries should have the same extension an
-	  # archive normally would.
-	  oldlibs="$output_objdir/$libname.$libext $oldlibs"
-	  build_libtool_libs=convenience
-	  build_old_libs=yes
-	fi
-
-	test -n "$vinfo" && \
-	  func_warning "\`-version-info/-version-number' is ignored for convenience libraries"
-
-	test -n "$release" && \
-	  func_warning "\`-release' is ignored for convenience libraries"
-      else
-
-	# Parse the version information argument.
-	save_ifs="$IFS"; IFS=':'
-	set dummy $vinfo 0 0 0
-	shift
-	IFS="$save_ifs"
-
-	test -n "$7" && \
-	  func_fatal_help "too many parameters to \`-version-info'"
-
-	# convert absolute version numbers to libtool ages
-	# this retains compatibility with .la files and attempts
-	# to make the code below a bit more comprehensible
-
-	case $vinfo_number in
-	yes)
-	  number_major="$1"
-	  number_minor="$2"
-	  number_revision="$3"
-	  #
-	  # There are really only two kinds -- those that
-	  # use the current revision as the major version
-	  # and those that subtract age and use age as
-	  # a minor version.  But, then there is irix
-	  # which has an extra 1 added just for fun
-	  #
-	  case $version_type in
-	  # correct linux to gnu/linux during the next big refactor
-	  darwin|linux|osf|windows|none)
-	    func_arith $number_major + $number_minor
-	    current=$func_arith_result
-	    age="$number_minor"
-	    revision="$number_revision"
-	    ;;
-	  freebsd-aout|freebsd-elf|qnx|sunos)
-	    current="$number_major"
-	    revision="$number_minor"
-	    age="0"
-	    ;;
-	  irix|nonstopux)
-	    func_arith $number_major + $number_minor
-	    current=$func_arith_result
-	    age="$number_minor"
-	    revision="$number_minor"
-	    lt_irix_increment=no
-	    ;;
-	  esac
-	  ;;
-	no)
-	  current="$1"
-	  revision="$2"
-	  age="$3"
-	  ;;
-	esac
-
-	# Check that each of the things are valid numbers.
-	case $current in
-	0|[1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9][0-9][0-9]) ;;
-	*)
-	  func_error "CURRENT \`$current' must be a nonnegative integer"
-	  func_fatal_error "\`$vinfo' is not valid version information"
-	  ;;
-	esac
-
-	case $revision in
-	0|[1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9][0-9][0-9]) ;;
-	*)
-	  func_error "REVISION \`$revision' must be a nonnegative integer"
-	  func_fatal_error "\`$vinfo' is not valid version information"
-	  ;;
-	esac
-
-	case $age in
-	0|[1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9][0-9][0-9]) ;;
-	*)
-	  func_error "AGE \`$age' must be a nonnegative integer"
-	  func_fatal_error "\`$vinfo' is not valid version information"
-	  ;;
-	esac
-
-	if test "$age" -gt "$current"; then
-	  func_error "AGE \`$age' is greater than the current interface number \`$current'"
-	  func_fatal_error "\`$vinfo' is not valid version information"
-	fi
-
-	# Calculate the version variables.
-	major=
-	versuffix=
-	verstring=
-	case $version_type in
-	none) ;;
-
-	darwin)
-	  # Like Linux, but with the current version available in
-	  # verstring for coding it into the library header
-	  func_arith $current - $age
-	  major=.$func_arith_result
-	  versuffix="$major.$age.$revision"
-	  # Darwin ld doesn't like 0 for these options...
-	  func_arith $current + 1
-	  minor_current=$func_arith_result
-	  xlcverstring="${wl}-compatibility_version ${wl}$minor_current ${wl}-current_version ${wl}$minor_current.$revision"
-	  verstring="-compatibility_version $minor_current -current_version $minor_current.$revision"
-	  ;;
-
-	freebsd-aout)
-	  major=".$current"
-	  versuffix=".$current.$revision";
-	  ;;
-
-	freebsd-elf)
-	  major=".$current"
-	  versuffix=".$current"
-	  ;;
-
-	irix | nonstopux)
-	  if test "X$lt_irix_increment" = "Xno"; then
-	    func_arith $current - $age
-	  else
-	    func_arith $current - $age + 1
-	  fi
-	  major=$func_arith_result
-
-	  case $version_type in
-	    nonstopux) verstring_prefix=nonstopux ;;
-	    *)         verstring_prefix=sgi ;;
-	  esac
-	  verstring="$verstring_prefix$major.$revision"
-
-	  # Add in all the interfaces that we are compatible with.
-	  loop=$revision
-	  while test "$loop" -ne 0; do
-	    func_arith $revision - $loop
-	    iface=$func_arith_result
-	    func_arith $loop - 1
-	    loop=$func_arith_result
-	    verstring="$verstring_prefix$major.$iface:$verstring"
-	  done
-
-	  # Before this point, $major must not contain `.'.
-	  major=.$major
-	  versuffix="$major.$revision"
-	  ;;
-
-	linux) # correct to gnu/linux during the next big refactor
-	  func_arith $current - $age
-	  major=.$func_arith_result
-	  versuffix="$major.$age.$revision"
-	  ;;
-
-	osf)
-	  func_arith $current - $age
-	  major=.$func_arith_result
-	  versuffix=".$current.$age.$revision"
-	  verstring="$current.$age.$revision"
-
-	  # Add in all the interfaces that we are compatible with.
-	  loop=$age
-	  while test "$loop" -ne 0; do
-	    func_arith $current - $loop
-	    iface=$func_arith_result
-	    func_arith $loop - 1
-	    loop=$func_arith_result
-	    verstring="$verstring:${iface}.0"
-	  done
-
-	  # Make executables depend on our current version.
-	  func_append verstring ":${current}.0"
-	  ;;
-
-	qnx)
-	  major=".$current"
-	  versuffix=".$current"
-	  ;;
-
-	sunos)
-	  major=".$current"
-	  versuffix=".$current.$revision"
-	  ;;
-
-	windows)
-	  # Use '-' rather than '.', since we only want one
-	  # extension on DOS 8.3 filesystems.
-	  func_arith $current - $age
-	  major=$func_arith_result
-	  versuffix="-$major"
-	  ;;
-
-	*)
-	  func_fatal_configuration "unknown library version type \`$version_type'"
-	  ;;
-	esac
-
-	# Clear the version info if we defaulted, and they specified a release.
-	if test -z "$vinfo" && test -n "$release"; then
-	  major=
-	  case $version_type in
-	  darwin)
-	    # we can't check for "0.0" in archive_cmds due to quoting
-	    # problems, so we reset it completely
-	    verstring=
-	    ;;
-	  *)
-	    verstring="0.0"
-	    ;;
-	  esac
-	  if test "$need_version" = no; then
-	    versuffix=
-	  else
-	    versuffix=".0.0"
-	  fi
-	fi
-
-	# Remove version info from name if versioning should be avoided
-	if test "$avoid_version" = yes && test "$need_version" = no; then
-	  major=
-	  versuffix=
-	  verstring=""
-	fi
-
-	# Check to see if the archive will have undefined symbols.
-	if test "$allow_undefined" = yes; then
-	  if test "$allow_undefined_flag" = unsupported; then
-	    func_warning "undefined symbols not allowed in $host shared libraries"
-	    build_libtool_libs=no
-	    build_old_libs=yes
-	  fi
-	else
-	  # Don't allow undefined symbols.
-	  allow_undefined_flag="$no_undefined_flag"
-	fi
-
-      fi
-
-      func_generate_dlsyms "$libname" "$libname" "yes"
-      func_append libobjs " $symfileobj"
-      test "X$libobjs" = "X " && libobjs=
-
-      if test "$opt_mode" != relink; then
-	# Remove our outputs, but don't remove object files since they
-	# may have been created when compiling PIC objects.
-	removelist=
-	tempremovelist=`$ECHO "$output_objdir/*"`
-	for p in $tempremovelist; do
-	  case $p in
-	    *.$objext | *.gcno)
-	       ;;
-	    $output_objdir/$outputname | $output_objdir/$libname.* | $output_objdir/${libname}${release}.*)
-	       if test "X$precious_files_regex" != "X"; then
-		 if $ECHO "$p" | $EGREP -e "$precious_files_regex" >/dev/null 2>&1
-		 then
-		   continue
-		 fi
-	       fi
-	       func_append removelist " $p"
-	       ;;
-	    *) ;;
-	  esac
-	done
-	test -n "$removelist" && \
-	  func_show_eval "${RM}r \$removelist"
-      fi
-
-      # Now set the variables for building old libraries.
-      if test "$build_old_libs" = yes && test "$build_libtool_libs" != convenience ; then
-	func_append oldlibs " $output_objdir/$libname.$libext"
-
-	# Transform .lo files to .o files.
-	oldobjs="$objs "`$ECHO "$libobjs" | $SP2NL | $SED "/\.${libext}$/d; $lo2o" | $NL2SP`
-      fi
-
-      # Eliminate all temporary directories.
-      #for path in $notinst_path; do
-      #	lib_search_path=`$ECHO "$lib_search_path " | $SED "s% $path % %g"`
-      #	deplibs=`$ECHO "$deplibs " | $SED "s% -L$path % %g"`
-      #	dependency_libs=`$ECHO "$dependency_libs " | $SED "s% -L$path % %g"`
-      #done
-
-      if test -n "$xrpath"; then
-	# If the user specified any rpath flags, then add them.
-	temp_xrpath=
-	for libdir in $xrpath; do
-	  func_replace_sysroot "$libdir"
-	  func_append temp_xrpath " -R$func_replace_sysroot_result"
-	  case "$finalize_rpath " in
-	  *" $libdir "*) ;;
-	  *) func_append finalize_rpath " $libdir" ;;
-	  esac
-	done
-	if test "$hardcode_into_libs" != yes || test "$build_old_libs" = yes; then
-	  dependency_libs="$temp_xrpath $dependency_libs"
-	fi
-      fi
-
-      # Make sure dlfiles contains only unique files that won't be dlpreopened
-      old_dlfiles="$dlfiles"
-      dlfiles=
-      for lib in $old_dlfiles; do
-	case " $dlprefiles $dlfiles " in
-	*" $lib "*) ;;
-	*) func_append dlfiles " $lib" ;;
-	esac
-      done
-
-      # Make sure dlprefiles contains only unique files
-      old_dlprefiles="$dlprefiles"
-      dlprefiles=
-      for lib in $old_dlprefiles; do
-	case "$dlprefiles " in
-	*" $lib "*) ;;
-	*) func_append dlprefiles " $lib" ;;
-	esac
-      done
-
-      if test "$build_libtool_libs" = yes; then
-	if test -n "$rpath"; then
-	  case $host in
-	  *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-beos* | *-cegcc* | *-*-haiku*)
-	    # these systems don't actually have a c library (as such)!
-	    ;;
-	  *-*-rhapsody* | *-*-darwin1.[012])
-	    # Rhapsody C library is in the System framework
-	    func_append deplibs " System.ltframework"
-	    ;;
-	  *-*-netbsd*)
-	    # Don't link with libc until the a.out ld.so is fixed.
-	    ;;
-	  *-*-openbsd* | *-*-freebsd* | *-*-dragonfly*)
-	    # Do not include libc due to us having libc/libc_r.
-	    ;;
-	  *-*-sco3.2v5* | *-*-sco5v6*)
-	    # Causes problems with __ctype
-	    ;;
-	  *-*-sysv4.2uw2* | *-*-sysv5* | *-*-unixware* | *-*-OpenUNIX*)
-	    # Compiler inserts libc in the correct place for threads to work
-	    ;;
-	  *)
-	    # Add libc to deplibs on all other systems if necessary.
-	    if test "$build_libtool_need_lc" = "yes"; then
-	      func_append deplibs " -lc"
-	    fi
-	    ;;
-	  esac
-	fi
-
-	# Transform deplibs into only deplibs that can be linked in shared.
-	name_save=$name
-	libname_save=$libname
-	release_save=$release
-	versuffix_save=$versuffix
-	major_save=$major
-	# I'm not sure if I'm treating the release correctly.  I think
-	# release should show up in the -l (ie -lgmp5) so we don't want to
-	# add it in twice.  Is that correct?
-	release=""
-	versuffix=""
-	major=""
-	newdeplibs=
-	droppeddeps=no
-	case $deplibs_check_method in
-	pass_all)
-	  # Don't check for shared/static.  Everything works.
-	  # This might be a little naive.  We might want to check
-	  # whether the library exists or not.  But this is on
-	  # osf3 & osf4 and I'm not really sure... Just
-	  # implementing what was already the behavior.
-	  newdeplibs=$deplibs
-	  ;;
-	test_compile)
-	  # This code stresses the "libraries are programs" paradigm to its
-	  # limits. Maybe even breaks it.  We compile a program, linking it
-	  # against the deplibs as a proxy for the library.  Then we can check
-	  # whether they linked in statically or dynamically with ldd.
-	  $opt_dry_run || $RM conftest.c
-	  cat > conftest.c <<EOF
-	  int main() { return 0; }
-EOF
-	  $opt_dry_run || $RM conftest
-	  if $LTCC $LTCFLAGS -o conftest conftest.c $deplibs; then
-	    ldd_output=`ldd conftest`
-	    for i in $deplibs; do
-	      case $i in
-	      -l*)
-		func_stripname -l '' "$i"
-		name=$func_stripname_result
-		if test "X$allow_libtool_libs_with_static_runtimes" = "Xyes" ; then
-		  case " $predeps $postdeps " in
-		  *" $i "*)
-		    func_append newdeplibs " $i"
-		    i=""
-		    ;;
-		  esac
-		fi
-		if test -n "$i" ; then
-		  libname=`eval "\\$ECHO \"$libname_spec\""`
-		  deplib_matches=`eval "\\$ECHO \"$library_names_spec\""`
-		  set dummy $deplib_matches; shift
-		  deplib_match=$1
-		  if test `expr "$ldd_output" : ".*$deplib_match"` -ne 0 ; then
-		    func_append newdeplibs " $i"
-		  else
-		    droppeddeps=yes
-		    echo
-		    $ECHO "*** Warning: dynamic linker does not accept needed library $i."
-		    echo "*** I have the capability to make that library automatically link in when"
-		    echo "*** you link to this library.  But I can only do this if you have a"
-		    echo "*** shared version of the library, which I believe you do not have"
-		    echo "*** because a test_compile did reveal that the linker did not use it for"
-		    echo "*** its dynamic dependency list that programs get resolved with at runtime."
-		  fi
-		fi
-		;;
-	      *)
-		func_append newdeplibs " $i"
-		;;
-	      esac
-	    done
-	  else
-	    # Error occurred in the first compile.  Let's try to salvage
-	    # the situation: Compile a separate program for each library.
-	    for i in $deplibs; do
-	      case $i in
-	      -l*)
-		func_stripname -l '' "$i"
-		name=$func_stripname_result
-		$opt_dry_run || $RM conftest
-		if $LTCC $LTCFLAGS -o conftest conftest.c $i; then
-		  ldd_output=`ldd conftest`
-		  if test "X$allow_libtool_libs_with_static_runtimes" = "Xyes" ; then
-		    case " $predeps $postdeps " in
-		    *" $i "*)
-		      func_append newdeplibs " $i"
-		      i=""
-		      ;;
-		    esac
-		  fi
-		  if test -n "$i" ; then
-		    libname=`eval "\\$ECHO \"$libname_spec\""`
-		    deplib_matches=`eval "\\$ECHO \"$library_names_spec\""`
-		    set dummy $deplib_matches; shift
-		    deplib_match=$1
-		    if test `expr "$ldd_output" : ".*$deplib_match"` -ne 0 ; then
-		      func_append newdeplibs " $i"
-		    else
-		      droppeddeps=yes
-		      echo
-		      $ECHO "*** Warning: dynamic linker does not accept needed library $i."
-		      echo "*** I have the capability to make that library automatically link in when"
-		      echo "*** you link to this library.  But I can only do this if you have a"
-		      echo "*** shared version of the library, which you do not appear to have"
-		      echo "*** because a test_compile did reveal that the linker did not use this one"
-		      echo "*** as a dynamic dependency that programs can get resolved with at runtime."
-		    fi
-		  fi
-		else
-		  droppeddeps=yes
-		  echo
-		  $ECHO "*** Warning!  Library $i is needed by this library but I was not able to"
-		  echo "*** make it link in!  You will probably need to install it or some"
-		  echo "*** library that it depends on before this library will be fully"
-		  echo "*** functional.  Installing it before continuing would be even better."
-		fi
-		;;
-	      *)
-		func_append newdeplibs " $i"
-		;;
-	      esac
-	    done
-	  fi
-	  ;;
-	file_magic*)
-	  set dummy $deplibs_check_method; shift
-	  file_magic_regex=`expr "$deplibs_check_method" : "$1 \(.*\)"`
-	  for a_deplib in $deplibs; do
-	    case $a_deplib in
-	    -l*)
-	      func_stripname -l '' "$a_deplib"
-	      name=$func_stripname_result
-	      if test "X$allow_libtool_libs_with_static_runtimes" = "Xyes" ; then
-		case " $predeps $postdeps " in
-		*" $a_deplib "*)
-		  func_append newdeplibs " $a_deplib"
-		  a_deplib=""
-		  ;;
-		esac
-	      fi
-	      if test -n "$a_deplib" ; then
-		libname=`eval "\\$ECHO \"$libname_spec\""`
-		if test -n "$file_magic_glob"; then
-		  libnameglob=`func_echo_all "$libname" | $SED -e $file_magic_glob`
-		else
-		  libnameglob=$libname
-		fi
-		test "$want_nocaseglob" = yes && nocaseglob=`shopt -p nocaseglob`
-		for i in $lib_search_path $sys_lib_search_path $shlib_search_path; do
-		  if test "$want_nocaseglob" = yes; then
-		    shopt -s nocaseglob
-		    potential_libs=`ls $i/$libnameglob[.-]* 2>/dev/null`
-		    $nocaseglob
-		  else
-		    potential_libs=`ls $i/$libnameglob[.-]* 2>/dev/null`
-		  fi
-		  for potent_lib in $potential_libs; do
-		      # Follow soft links.
-		      if ls -lLd "$potent_lib" 2>/dev/null |
-			 $GREP " -> " >/dev/null; then
-			continue
-		      fi
-		      # The statement above tries to avoid entering an
-		      # endless loop below, in case of cyclic links.
-		      # We might still enter an endless loop, since a link
-		      # loop can be closed while we follow links,
-		      # but so what?
-		      potlib="$potent_lib"
-		      while test -h "$potlib" 2>/dev/null; do
-			potliblink=`ls -ld $potlib | ${SED} 's/.* -> //'`
-			case $potliblink in
-			[\\/]* | [A-Za-z]:[\\/]*) potlib="$potliblink";;
-			*) potlib=`$ECHO "$potlib" | $SED 's,[^/]*$,,'`"$potliblink";;
-			esac
-		      done
-		      if eval $file_magic_cmd \"\$potlib\" 2>/dev/null |
-			 $SED -e 10q |
-			 $EGREP "$file_magic_regex" > /dev/null; then
-			func_append newdeplibs " $a_deplib"
-			a_deplib=""
-			break 2
-		      fi
-		  done
-		done
-	      fi
-	      if test -n "$a_deplib" ; then
-		droppeddeps=yes
-		echo
-		$ECHO "*** Warning: linker path does not have real file for library $a_deplib."
-		echo "*** I have the capability to make that library automatically link in when"
-		echo "*** you link to this library.  But I can only do this if you have a"
-		echo "*** shared version of the library, which you do not appear to have"
-		echo "*** because I did check the linker path looking for a file starting"
-		if test -z "$potlib" ; then
-		  $ECHO "*** with $libname but no candidates were found. (...for file magic test)"
-		else
-		  $ECHO "*** with $libname and none of the candidates passed a file format test"
-		  $ECHO "*** using a file magic. Last file checked: $potlib"
-		fi
-	      fi
-	      ;;
-	    *)
-	      # Add a -L argument.
-	      func_append newdeplibs " $a_deplib"
-	      ;;
-	    esac
-	  done # Gone through all deplibs.
-	  ;;
-	match_pattern*)
-	  set dummy $deplibs_check_method; shift
-	  match_pattern_regex=`expr "$deplibs_check_method" : "$1 \(.*\)"`
-	  for a_deplib in $deplibs; do
-	    case $a_deplib in
-	    -l*)
-	      func_stripname -l '' "$a_deplib"
-	      name=$func_stripname_result
-	      if test "X$allow_libtool_libs_with_static_runtimes" = "Xyes" ; then
-		case " $predeps $postdeps " in
-		*" $a_deplib "*)
-		  func_append newdeplibs " $a_deplib"
-		  a_deplib=""
-		  ;;
-		esac
-	      fi
-	      if test -n "$a_deplib" ; then
-		libname=`eval "\\$ECHO \"$libname_spec\""`
-		for i in $lib_search_path $sys_lib_search_path $shlib_search_path; do
-		  potential_libs=`ls $i/$libname[.-]* 2>/dev/null`
-		  for potent_lib in $potential_libs; do
-		    potlib="$potent_lib" # see symlink-check above in file_magic test
-		    if eval "\$ECHO \"$potent_lib\"" 2>/dev/null | $SED 10q | \
-		       $EGREP "$match_pattern_regex" > /dev/null; then
-		      func_append newdeplibs " $a_deplib"
-		      a_deplib=""
-		      break 2
-		    fi
-		  done
-		done
-	      fi
-	      if test -n "$a_deplib" ; then
-		droppeddeps=yes
-		echo
-		$ECHO "*** Warning: linker path does not have real file for library $a_deplib."
-		echo "*** I have the capability to make that library automatically link in when"
-		echo "*** you link to this library.  But I can only do this if you have a"
-		echo "*** shared version of the library, which you do not appear to have"
-		echo "*** because I did check the linker path looking for a file starting"
-		if test -z "$potlib" ; then
-		  $ECHO "*** with $libname but no candidates were found. (...for regex pattern test)"
-		else
-		  $ECHO "*** with $libname and none of the candidates passed a file format test"
-		  $ECHO "*** using a regex pattern. Last file checked: $potlib"
-		fi
-	      fi
-	      ;;
-	    *)
-	      # Add a -L argument.
-	      func_append newdeplibs " $a_deplib"
-	      ;;
-	    esac
-	  done # Gone through all deplibs.
-	  ;;
-	none | unknown | *)
-	  newdeplibs=""
-	  tmp_deplibs=`$ECHO " $deplibs" | $SED 's/ -lc$//; s/ -[LR][^ ]*//g'`
-	  if test "X$allow_libtool_libs_with_static_runtimes" = "Xyes" ; then
-	    for i in $predeps $postdeps ; do
-	      # can't use Xsed below, because $i might contain '/'
-	      tmp_deplibs=`$ECHO " $tmp_deplibs" | $SED "s,$i,,"`
-	    done
-	  fi
-	  case $tmp_deplibs in
-	  *[!\	\ ]*)
-	    echo
-	    if test "X$deplibs_check_method" = "Xnone"; then
-	      echo "*** Warning: inter-library dependencies are not supported in this platform."
-	    else
-	      echo "*** Warning: inter-library dependencies are not known to be supported."
-	    fi
-	    echo "*** All declared inter-library dependencies are being dropped."
-	    droppeddeps=yes
-	    ;;
-	  esac
-	  ;;
-	esac
-	versuffix=$versuffix_save
-	major=$major_save
-	release=$release_save
-	libname=$libname_save
-	name=$name_save
-
-	case $host in
-	*-*-rhapsody* | *-*-darwin1.[012])
-	  # On Rhapsody replace the C library with the System framework
-	  newdeplibs=`$ECHO " $newdeplibs" | $SED 's/ -lc / System.ltframework /'`
-	  ;;
-	esac
-
-	if test "$droppeddeps" = yes; then
-	  if test "$module" = yes; then
-	    echo
-	    echo "*** Warning: libtool could not satisfy all declared inter-library"
-	    $ECHO "*** dependencies of module $libname.  Therefore, libtool will create"
-	    echo "*** a static module, that should work as long as the dlopening"
-	    echo "*** application is linked with the -dlopen flag."
-	    if test -z "$global_symbol_pipe"; then
-	      echo
-	      echo "*** However, this would only work if libtool was able to extract symbol"
-	      echo "*** lists from a program, using \`nm' or equivalent, but libtool could"
-	      echo "*** not find such a program.  So, this module is probably useless."
-	      echo "*** \`nm' from GNU binutils and a full rebuild may help."
-	    fi
-	    if test "$build_old_libs" = no; then
-	      oldlibs="$output_objdir/$libname.$libext"
-	      build_libtool_libs=module
-	      build_old_libs=yes
-	    else
-	      build_libtool_libs=no
-	    fi
-	  else
-	    echo "*** The inter-library dependencies that have been dropped here will be"
-	    echo "*** automatically added whenever a program is linked with this library"
-	    echo "*** or is declared to -dlopen it."
-
-	    if test "$allow_undefined" = no; then
-	      echo
-	      echo "*** Since this library must not contain undefined symbols,"
-	      echo "*** because either the platform does not support them or"
-	      echo "*** it was explicitly requested with -no-undefined,"
-	      echo "*** libtool will only create a static version of it."
-	      if test "$build_old_libs" = no; then
-		oldlibs="$output_objdir/$libname.$libext"
-		build_libtool_libs=module
-		build_old_libs=yes
-	      else
-		build_libtool_libs=no
-	      fi
-	    fi
-	  fi
-	fi
-	# Done checking deplibs!
-	deplibs=$newdeplibs
-      fi
-      # Time to change all our "foo.ltframework" stuff back to "-framework foo"
-      case $host in
-	*-*-darwin*)
-	  newdeplibs=`$ECHO " $newdeplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
-	  new_inherited_linker_flags=`$ECHO " $new_inherited_linker_flags" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
-	  deplibs=`$ECHO " $deplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
-	  ;;
-      esac
-
-      # move library search paths that coincide with paths to not yet
-      # installed libraries to the beginning of the library search list
-      new_libs=
-      for path in $notinst_path; do
-	case " $new_libs " in
-	*" -L$path/$objdir "*) ;;
-	*)
-	  case " $deplibs " in
-	  *" -L$path/$objdir "*)
-	    func_append new_libs " -L$path/$objdir" ;;
-	  esac
-	  ;;
-	esac
-      done
-      for deplib in $deplibs; do
-	case $deplib in
-	-L*)
-	  case " $new_libs " in
-	  *" $deplib "*) ;;
-	  *) func_append new_libs " $deplib" ;;
-	  esac
-	  ;;
-	*) func_append new_libs " $deplib" ;;
-	esac
-      done
-      deplibs="$new_libs"
-
-      # All the library-specific variables (install_libdir is set above).
-      library_names=
-      old_library=
-      dlname=
-
-      # Test again, we may have decided not to build it any more
-      if test "$build_libtool_libs" = yes; then
-	# Remove ${wl} instances when linking with ld.
-	# FIXME: should test the right _cmds variable.
-	case $archive_cmds in
-	  *\$LD\ *) wl= ;;
-        esac
-	if test "$hardcode_into_libs" = yes; then
-	  # Hardcode the library paths
-	  hardcode_libdirs=
-	  dep_rpath=
-	  rpath="$finalize_rpath"
-	  test "$opt_mode" != relink && rpath="$compile_rpath$rpath"
-	  for libdir in $rpath; do
-	    if test -n "$hardcode_libdir_flag_spec"; then
-	      if test -n "$hardcode_libdir_separator"; then
-		func_replace_sysroot "$libdir"
-		libdir=$func_replace_sysroot_result
-		if test -z "$hardcode_libdirs"; then
-		  hardcode_libdirs="$libdir"
-		else
-		  # Just accumulate the unique libdirs.
-		  case $hardcode_libdir_separator$hardcode_libdirs$hardcode_libdir_separator in
-		  *"$hardcode_libdir_separator$libdir$hardcode_libdir_separator"*)
-		    ;;
-		  *)
-		    func_append hardcode_libdirs "$hardcode_libdir_separator$libdir"
-		    ;;
-		  esac
-		fi
-	      else
-		eval flag=\"$hardcode_libdir_flag_spec\"
-		func_append dep_rpath " $flag"
-	      fi
-	    elif test -n "$runpath_var"; then
-	      case "$perm_rpath " in
-	      *" $libdir "*) ;;
-	      *) func_append perm_rpath " $libdir" ;;
-	      esac
-	    fi
-	  done
-	  # Substitute the hardcoded libdirs into the rpath.
-	  if test -n "$hardcode_libdir_separator" &&
-	     test -n "$hardcode_libdirs"; then
-	    libdir="$hardcode_libdirs"
-	    eval "dep_rpath=\"$hardcode_libdir_flag_spec\""
-	  fi
-	  if test -n "$runpath_var" && test -n "$perm_rpath"; then
-	    # We should set the runpath_var.
-	    rpath=
-	    for dir in $perm_rpath; do
-	      func_append rpath "$dir:"
-	    done
-	    eval "$runpath_var='$rpath\$$runpath_var'; export $runpath_var"
-	  fi
-	  test -n "$dep_rpath" && deplibs="$dep_rpath $deplibs"
-	fi
-
-	shlibpath="$finalize_shlibpath"
-	test "$opt_mode" != relink && shlibpath="$compile_shlibpath$shlibpath"
-	if test -n "$shlibpath"; then
-	  eval "$shlibpath_var='$shlibpath\$$shlibpath_var'; export $shlibpath_var"
-	fi
-
-	# Get the real and link names of the library.
-	eval shared_ext=\"$shrext_cmds\"
-	eval library_names=\"$library_names_spec\"
-	set dummy $library_names
-	shift
-	realname="$1"
-	shift
-
-	if test -n "$soname_spec"; then
-	  eval soname=\"$soname_spec\"
-	else
-	  soname="$realname"
-	fi
-	if test -z "$dlname"; then
-	  dlname=$soname
-	fi
-
-	lib="$output_objdir/$realname"
-	linknames=
-	for link
-	do
-	  func_append linknames " $link"
-	done
-
-	# Use standard objects if they are pic
-	test -z "$pic_flag" && libobjs=`$ECHO "$libobjs" | $SP2NL | $SED "$lo2o" | $NL2SP`
-	test "X$libobjs" = "X " && libobjs=
-
-	delfiles=
-	if test -n "$export_symbols" && test -n "$include_expsyms"; then
-	  $opt_dry_run || cp "$export_symbols" "$output_objdir/$libname.uexp"
-	  export_symbols="$output_objdir/$libname.uexp"
-	  func_append delfiles " $export_symbols"
-	fi
-
-	orig_export_symbols=
-	case $host_os in
-	cygwin* | mingw* | cegcc*)
-	  if test -n "$export_symbols" && test -z "$export_symbols_regex"; then
-	    # exporting using user supplied symfile
-	    if test "x`$SED 1q $export_symbols`" != xEXPORTS; then
-	      # and it's NOT already a .def file. Must figure out
-	      # which of the given symbols are data symbols and tag
-	      # them as such. So, trigger use of export_symbols_cmds.
-	      # export_symbols gets reassigned inside the "prepare
-	      # the list of exported symbols" if statement, so the
-	      # include_expsyms logic still works.
-	      orig_export_symbols="$export_symbols"
-	      export_symbols=
-	      always_export_symbols=yes
-	    fi
-	  fi
-	  ;;
-	esac
-
-	# Prepare the list of exported symbols
-	if test -z "$export_symbols"; then
-	  if test "$always_export_symbols" = yes || test -n "$export_symbols_regex"; then
-	    func_verbose "generating symbol list for \`$libname.la'"
-	    export_symbols="$output_objdir/$libname.exp"
-	    $opt_dry_run || $RM $export_symbols
-	    cmds=$export_symbols_cmds
-	    save_ifs="$IFS"; IFS='~'
-	    for cmd1 in $cmds; do
-	      IFS="$save_ifs"
-	      # Take the normal branch if the nm_file_list_spec branch
-	      # doesn't work or if tool conversion is not needed.
-	      case $nm_file_list_spec~$to_tool_file_cmd in
-		*~func_convert_file_noop | *~func_convert_file_msys_to_w32 | ~*)
-		  try_normal_branch=yes
-		  eval cmd=\"$cmd1\"
-		  func_len " $cmd"
-		  len=$func_len_result
-		  ;;
-		*)
-		  try_normal_branch=no
-		  ;;
-	      esac
-	      if test "$try_normal_branch" = yes \
-		 && { test "$len" -lt "$max_cmd_len" \
-		      || test "$max_cmd_len" -le -1; }
-	      then
-		func_show_eval "$cmd" 'exit $?'
-		skipped_export=false
-	      elif test -n "$nm_file_list_spec"; then
-		func_basename "$output"
-		output_la=$func_basename_result
-		save_libobjs=$libobjs
-		save_output=$output
-		output=${output_objdir}/${output_la}.nm
-		func_to_tool_file "$output"
-		libobjs=$nm_file_list_spec$func_to_tool_file_result
-		func_append delfiles " $output"
-		func_verbose "creating $NM input file list: $output"
-		for obj in $save_libobjs; do
-		  func_to_tool_file "$obj"
-		  $ECHO "$func_to_tool_file_result"
-		done > "$output"
-		eval cmd=\"$cmd1\"
-		func_show_eval "$cmd" 'exit $?'
-		output=$save_output
-		libobjs=$save_libobjs
-		skipped_export=false
-	      else
-		# The command line is too long to execute in one step.
-		func_verbose "using reloadable object file for export list..."
-		skipped_export=:
-		# Break out early, otherwise skipped_export may be
-		# set to false by a later but shorter cmd.
-		break
-	      fi
-	    done
-	    IFS="$save_ifs"
-	    if test -n "$export_symbols_regex" && test "X$skipped_export" != "X:"; then
-	      func_show_eval '$EGREP -e "$export_symbols_regex" "$export_symbols" > "${export_symbols}T"'
-	      func_show_eval '$MV "${export_symbols}T" "$export_symbols"'
-	    fi
-	  fi
-	fi
-
-	if test -n "$export_symbols" && test -n "$include_expsyms"; then
-	  tmp_export_symbols="$export_symbols"
-	  test -n "$orig_export_symbols" && tmp_export_symbols="$orig_export_symbols"
-	  $opt_dry_run || eval '$ECHO "$include_expsyms" | $SP2NL >> "$tmp_export_symbols"'
-	fi
-
-	if test "X$skipped_export" != "X:" && test -n "$orig_export_symbols"; then
-	  # The given exports_symbols file has to be filtered, so filter it.
-	  func_verbose "filter symbol list for \`$libname.la' to tag DATA exports"
-	  # FIXME: $output_objdir/$libname.filter potentially contains lots of
-	  # 's' commands which not all seds can handle. GNU sed should be fine
-	  # though. Also, the filter scales superlinearly with the number of
-	  # global variables. join(1) would be nice here, but unfortunately
-	  # isn't a blessed tool.
-	  $opt_dry_run || $SED -e '/[ ,]DATA/!d;s,\(.*\)\([ \,].*\),s|^\1$|\1\2|,' < $export_symbols > $output_objdir/$libname.filter
-	  func_append delfiles " $export_symbols $output_objdir/$libname.filter"
-	  export_symbols=$output_objdir/$libname.def
-	  $opt_dry_run || $SED -f $output_objdir/$libname.filter < $orig_export_symbols > $export_symbols
-	fi
-
-	tmp_deplibs=
-	for test_deplib in $deplibs; do
-	  case " $convenience " in
-	  *" $test_deplib "*) ;;
-	  *)
-	    func_append tmp_deplibs " $test_deplib"
-	    ;;
-	  esac
-	done
-	deplibs="$tmp_deplibs"
-
-	if test -n "$convenience"; then
-	  if test -n "$whole_archive_flag_spec" &&
-	    test "$compiler_needs_object" = yes &&
-	    test -z "$libobjs"; then
-	    # extract the archives, so we have objects to list.
-	    # TODO: could optimize this to just extract one archive.
-	    whole_archive_flag_spec=
-	  fi
-	  if test -n "$whole_archive_flag_spec"; then
-	    save_libobjs=$libobjs
-	    eval libobjs=\"\$libobjs $whole_archive_flag_spec\"
-	    test "X$libobjs" = "X " && libobjs=
-	  else
-	    gentop="$output_objdir/${outputname}x"
-	    func_append generated " $gentop"
-
-	    func_extract_archives $gentop $convenience
-	    func_append libobjs " $func_extract_archives_result"
-	    test "X$libobjs" = "X " && libobjs=
-	  fi
-	fi
-
-	if test "$thread_safe" = yes && test -n "$thread_safe_flag_spec"; then
-	  eval flag=\"$thread_safe_flag_spec\"
-	  func_append linker_flags " $flag"
-	fi
-
-	# Make a backup of the uninstalled library when relinking
-	if test "$opt_mode" = relink; then
-	  $opt_dry_run || eval '(cd $output_objdir && $RM ${realname}U && $MV $realname ${realname}U)' || exit $?
-	fi
-
-	# Do each of the archive commands.
-	if test "$module" = yes && test -n "$module_cmds" ; then
-	  if test -n "$export_symbols" && test -n "$module_expsym_cmds"; then
-	    eval test_cmds=\"$module_expsym_cmds\"
-	    cmds=$module_expsym_cmds
-	  else
-	    eval test_cmds=\"$module_cmds\"
-	    cmds=$module_cmds
-	  fi
-	else
-	  if test -n "$export_symbols" && test -n "$archive_expsym_cmds"; then
-	    eval test_cmds=\"$archive_expsym_cmds\"
-	    cmds=$archive_expsym_cmds
-	  else
-	    eval test_cmds=\"$archive_cmds\"
-	    cmds=$archive_cmds
-	  fi
-	fi
-
-	if test "X$skipped_export" != "X:" &&
-	   func_len " $test_cmds" &&
-	   len=$func_len_result &&
-	   test "$len" -lt "$max_cmd_len" || test "$max_cmd_len" -le -1; then
-	  :
-	else
-	  # The command line is too long to link in one step, link piecewise
-	  # or, if using GNU ld and skipped_export is not :, use a linker
-	  # script.
-
-	  # Save the value of $output and $libobjs because we want to
-	  # use them later.  If we have whole_archive_flag_spec, we
-	  # want to use save_libobjs as it was before
-	  # whole_archive_flag_spec was expanded, because we can't
-	  # assume the linker understands whole_archive_flag_spec.
-	  # This may have to be revisited, in case too many
-	  # convenience libraries get linked in and end up exceeding
-	  # the spec.
-	  if test -z "$convenience" || test -z "$whole_archive_flag_spec"; then
-	    save_libobjs=$libobjs
-	  fi
-	  save_output=$output
-	  func_basename "$output"
-	  output_la=$func_basename_result
-
-	  # Clear the reloadable object creation command queue and
-	  # initialize k to one.
-	  test_cmds=
-	  concat_cmds=
-	  objlist=
-	  last_robj=
-	  k=1
-
-	  if test -n "$save_libobjs" && test "X$skipped_export" != "X:" && test "$with_gnu_ld" = yes; then
-	    output=${output_objdir}/${output_la}.lnkscript
-	    func_verbose "creating GNU ld script: $output"
-	    echo 'INPUT (' > $output
-	    for obj in $save_libobjs
-	    do
-	      func_to_tool_file "$obj"
-	      $ECHO "$func_to_tool_file_result" >> $output
-	    done
-	    echo ')' >> $output
-	    func_append delfiles " $output"
-	    func_to_tool_file "$output"
-	    output=$func_to_tool_file_result
-	  elif test -n "$save_libobjs" && test "X$skipped_export" != "X:" && test "X$file_list_spec" != X; then
-	    output=${output_objdir}/${output_la}.lnk
-	    func_verbose "creating linker input file list: $output"
-	    : > $output
-	    set x $save_libobjs
-	    shift
-	    firstobj=
-	    if test "$compiler_needs_object" = yes; then
-	      firstobj="$1 "
-	      shift
-	    fi
-	    for obj
-	    do
-	      func_to_tool_file "$obj"
-	      $ECHO "$func_to_tool_file_result" >> $output
-	    done
-	    func_append delfiles " $output"
-	    func_to_tool_file "$output"
-	    output=$firstobj\"$file_list_spec$func_to_tool_file_result\"
-	  else
-	    if test -n "$save_libobjs"; then
-	      func_verbose "creating reloadable object files..."
-	      output=$output_objdir/$output_la-${k}.$objext
-	      eval test_cmds=\"$reload_cmds\"
-	      func_len " $test_cmds"
-	      len0=$func_len_result
-	      len=$len0
-
-	      # Loop over the list of objects to be linked.
-	      for obj in $save_libobjs
-	      do
-		func_len " $obj"
-		func_arith $len + $func_len_result
-		len=$func_arith_result
-		if test "X$objlist" = X ||
-		   test "$len" -lt "$max_cmd_len"; then
-		  func_append objlist " $obj"
-		else
-		  # The command $test_cmds is almost too long, add a
-		  # command to the queue.
-		  if test "$k" -eq 1 ; then
-		    # The first file doesn't have a previous command to add.
-		    reload_objs=$objlist
-		    eval concat_cmds=\"$reload_cmds\"
-		  else
-		    # All subsequent reloadable object files will link in
-		    # the last one created.
-		    reload_objs="$objlist $last_robj"
-		    eval concat_cmds=\"\$concat_cmds~$reload_cmds~\$RM $last_robj\"
-		  fi
-		  last_robj=$output_objdir/$output_la-${k}.$objext
-		  func_arith $k + 1
-		  k=$func_arith_result
-		  output=$output_objdir/$output_la-${k}.$objext
-		  objlist=" $obj"
-		  func_len " $last_robj"
-		  func_arith $len0 + $func_len_result
-		  len=$func_arith_result
-		fi
-	      done
-	      # Handle the remaining objects by creating one last
-	      # reloadable object file.  All subsequent reloadable object
-	      # files will link in the last one created.
-	      test -z "$concat_cmds" || concat_cmds=$concat_cmds~
-	      reload_objs="$objlist $last_robj"
-	      eval concat_cmds=\"\${concat_cmds}$reload_cmds\"
-	      if test -n "$last_robj"; then
-	        eval concat_cmds=\"\${concat_cmds}~\$RM $last_robj\"
-	      fi
-	      func_append delfiles " $output"
-
-	    else
-	      output=
-	    fi
-
-	    if ${skipped_export-false}; then
-	      func_verbose "generating symbol list for \`$libname.la'"
-	      export_symbols="$output_objdir/$libname.exp"
-	      $opt_dry_run || $RM $export_symbols
-	      libobjs=$output
-	      # Append the command to create the export file.
-	      test -z "$concat_cmds" || concat_cmds=$concat_cmds~
-	      eval concat_cmds=\"\$concat_cmds$export_symbols_cmds\"
-	      if test -n "$last_robj"; then
-		eval concat_cmds=\"\$concat_cmds~\$RM $last_robj\"
-	      fi
-	    fi
-
-	    test -n "$save_libobjs" &&
-	      func_verbose "creating a temporary reloadable object file: $output"
-
-	    # Loop through the commands generated above and execute them.
-	    save_ifs="$IFS"; IFS='~'
-	    for cmd in $concat_cmds; do
-	      IFS="$save_ifs"
-	      $opt_silent || {
-		  func_quote_for_expand "$cmd"
-		  eval "func_echo $func_quote_for_expand_result"
-	      }
-	      $opt_dry_run || eval "$cmd" || {
-		lt_exit=$?
-
-		# Restore the uninstalled library and exit
-		if test "$opt_mode" = relink; then
-		  ( cd "$output_objdir" && \
-		    $RM "${realname}T" && \
-		    $MV "${realname}U" "$realname" )
-		fi
-
-		exit $lt_exit
-	      }
-	    done
-	    IFS="$save_ifs"
-
-	    if test -n "$export_symbols_regex" && ${skipped_export-false}; then
-	      func_show_eval '$EGREP -e "$export_symbols_regex" "$export_symbols" > "${export_symbols}T"'
-	      func_show_eval '$MV "${export_symbols}T" "$export_symbols"'
-	    fi
-	  fi
-
-          if ${skipped_export-false}; then
-	    if test -n "$export_symbols" && test -n "$include_expsyms"; then
-	      tmp_export_symbols="$export_symbols"
-	      test -n "$orig_export_symbols" && tmp_export_symbols="$orig_export_symbols"
-	      $opt_dry_run || eval '$ECHO "$include_expsyms" | $SP2NL >> "$tmp_export_symbols"'
-	    fi
-
-	    if test -n "$orig_export_symbols"; then
-	      # The given exports_symbols file has to be filtered, so filter it.
-	      func_verbose "filter symbol list for \`$libname.la' to tag DATA exports"
-	      # FIXME: $output_objdir/$libname.filter potentially contains lots of
-	      # 's' commands which not all seds can handle. GNU sed should be fine
-	      # though. Also, the filter scales superlinearly with the number of
-	      # global variables. join(1) would be nice here, but unfortunately
-	      # isn't a blessed tool.
-	      $opt_dry_run || $SED -e '/[ ,]DATA/!d;s,\(.*\)\([ \,].*\),s|^\1$|\1\2|,' < $export_symbols > $output_objdir/$libname.filter
-	      func_append delfiles " $export_symbols $output_objdir/$libname.filter"
-	      export_symbols=$output_objdir/$libname.def
-	      $opt_dry_run || $SED -f $output_objdir/$libname.filter < $orig_export_symbols > $export_symbols
-	    fi
-	  fi
-
-	  libobjs=$output
-	  # Restore the value of output.
-	  output=$save_output
-
-	  if test -n "$convenience" && test -n "$whole_archive_flag_spec"; then
-	    eval libobjs=\"\$libobjs $whole_archive_flag_spec\"
-	    test "X$libobjs" = "X " && libobjs=
-	  fi
-	  # Expand the library linking commands again to reset the
-	  # value of $libobjs for piecewise linking.
-
-	  # Do each of the archive commands.
-	  if test "$module" = yes && test -n "$module_cmds" ; then
-	    if test -n "$export_symbols" && test -n "$module_expsym_cmds"; then
-	      cmds=$module_expsym_cmds
-	    else
-	      cmds=$module_cmds
-	    fi
-	  else
-	    if test -n "$export_symbols" && test -n "$archive_expsym_cmds"; then
-	      cmds=$archive_expsym_cmds
-	    else
-	      cmds=$archive_cmds
-	    fi
-	  fi
-	fi
-
-	if test -n "$delfiles"; then
-	  # Append the command to remove temporary files to $cmds.
-	  eval cmds=\"\$cmds~\$RM $delfiles\"
-	fi
-
-	# Add any objects from preloaded convenience libraries
-	if test -n "$dlprefiles"; then
-	  gentop="$output_objdir/${outputname}x"
-	  func_append generated " $gentop"
-
-	  func_extract_archives $gentop $dlprefiles
-	  func_append libobjs " $func_extract_archives_result"
-	  test "X$libobjs" = "X " && libobjs=
-	fi
-
-	save_ifs="$IFS"; IFS='~'
-	for cmd in $cmds; do
-	  IFS="$save_ifs"
-	  eval cmd=\"$cmd\"
-	  $opt_silent || {
-	    func_quote_for_expand "$cmd"
-	    eval "func_echo $func_quote_for_expand_result"
-	  }
-	  $opt_dry_run || eval "$cmd" || {
-	    lt_exit=$?
-
-	    # Restore the uninstalled library and exit
-	    if test "$opt_mode" = relink; then
-	      ( cd "$output_objdir" && \
-	        $RM "${realname}T" && \
-		$MV "${realname}U" "$realname" )
-	    fi
-
-	    exit $lt_exit
-	  }
-	done
-	IFS="$save_ifs"
-
-	# Restore the uninstalled library and exit
-	if test "$opt_mode" = relink; then
-	  $opt_dry_run || eval '(cd $output_objdir && $RM ${realname}T && $MV $realname ${realname}T && $MV ${realname}U $realname)' || exit $?
-
-	  if test -n "$convenience"; then
-	    if test -z "$whole_archive_flag_spec"; then
-	      func_show_eval '${RM}r "$gentop"'
-	    fi
-	  fi
-
-	  exit $EXIT_SUCCESS
-	fi
-
-	# Create links to the real library.
-	for linkname in $linknames; do
-	  if test "$realname" != "$linkname"; then
-	    func_show_eval '(cd "$output_objdir" && $RM "$linkname" && $LN_S "$realname" "$linkname")' 'exit $?'
-	  fi
-	done
-
-	# If -module or -export-dynamic was specified, set the dlname.
-	if test "$module" = yes || test "$export_dynamic" = yes; then
-	  # On all known operating systems, these are identical.
-	  dlname="$soname"
-	fi
-      fi
-      ;;
-
-    obj)
-      if test -n "$dlfiles$dlprefiles" || test "$dlself" != no; then
-	func_warning "\`-dlopen' is ignored for objects"
-      fi
-
-      case " $deplibs" in
-      *\ -l* | *\ -L*)
-	func_warning "\`-l' and \`-L' are ignored for objects" ;;
-      esac
-
-      test -n "$rpath" && \
-	func_warning "\`-rpath' is ignored for objects"
-
-      test -n "$xrpath" && \
-	func_warning "\`-R' is ignored for objects"
-
-      test -n "$vinfo" && \
-	func_warning "\`-version-info' is ignored for objects"
-
-      test -n "$release" && \
-	func_warning "\`-release' is ignored for objects"
-
-      case $output in
-      *.lo)
-	test -n "$objs$old_deplibs" && \
-	  func_fatal_error "cannot build library object \`$output' from non-libtool objects"
-
-	libobj=$output
-	func_lo2o "$libobj"
-	obj=$func_lo2o_result
-	;;
-      *)
-	libobj=
-	obj="$output"
-	;;
-      esac
-
-      # Delete the old objects.
-      $opt_dry_run || $RM $obj $libobj
-
-      # Objects from convenience libraries.  This assumes
-      # single-version convenience libraries.  Whenever we create
-      # different ones for PIC/non-PIC, this we'll have to duplicate
-      # the extraction.
-      reload_conv_objs=
-      gentop=
-      # reload_cmds runs $LD directly, so let us get rid of
-      # -Wl from whole_archive_flag_spec and hope we can get by with
-      # turning comma into space..
-      wl=
-
-      if test -n "$convenience"; then
-	if test -n "$whole_archive_flag_spec"; then
-	  eval tmp_whole_archive_flags=\"$whole_archive_flag_spec\"
-	  reload_conv_objs=$reload_objs\ `$ECHO "$tmp_whole_archive_flags" | $SED 's|,| |g'`
-	else
-	  gentop="$output_objdir/${obj}x"
-	  func_append generated " $gentop"
-
-	  func_extract_archives $gentop $convenience
-	  reload_conv_objs="$reload_objs $func_extract_archives_result"
-	fi
-      fi
-
-      # If we're not building shared, we need to use non_pic_objs
-      test "$build_libtool_libs" != yes && libobjs="$non_pic_objects"
-
-      # Create the old-style object.
-      reload_objs="$objs$old_deplibs "`$ECHO "$libobjs" | $SP2NL | $SED "/\.${libext}$/d; /\.lib$/d; $lo2o" | $NL2SP`" $reload_conv_objs" ### testsuite: skip nested quoting test
-
-      output="$obj"
-      func_execute_cmds "$reload_cmds" 'exit $?'
-
-      # Exit if we aren't doing a library object file.
-      if test -z "$libobj"; then
-	if test -n "$gentop"; then
-	  func_show_eval '${RM}r "$gentop"'
-	fi
-
-	exit $EXIT_SUCCESS
-      fi
-
-      if test "$build_libtool_libs" != yes; then
-	if test -n "$gentop"; then
-	  func_show_eval '${RM}r "$gentop"'
-	fi
-
-	# Create an invalid libtool object if no PIC, so that we don't
-	# accidentally link it into a program.
-	# $show "echo timestamp > $libobj"
-	# $opt_dry_run || eval "echo timestamp > $libobj" || exit $?
-	exit $EXIT_SUCCESS
-      fi
-
-      if test -n "$pic_flag" || test "$pic_mode" != default; then
-	# Only do commands if we really have different PIC objects.
-	reload_objs="$libobjs $reload_conv_objs"
-	output="$libobj"
-	func_execute_cmds "$reload_cmds" 'exit $?'
-      fi
-
-      if test -n "$gentop"; then
-	func_show_eval '${RM}r "$gentop"'
-      fi
-
-      exit $EXIT_SUCCESS
-      ;;
-
-    prog)
-      case $host in
-	*cygwin*) func_stripname '' '.exe' "$output"
-	          output=$func_stripname_result.exe;;
-      esac
-      test -n "$vinfo" && \
-	func_warning "\`-version-info' is ignored for programs"
-
-      test -n "$release" && \
-	func_warning "\`-release' is ignored for programs"
-
-      test "$preload" = yes \
-        && test "$dlopen_support" = unknown \
-	&& test "$dlopen_self" = unknown \
-	&& test "$dlopen_self_static" = unknown && \
-	  func_warning "\`LT_INIT([dlopen])' not used. Assuming no dlopen support."
-
-      case $host in
-      *-*-rhapsody* | *-*-darwin1.[012])
-	# On Rhapsody replace the C library is the System framework
-	compile_deplibs=`$ECHO " $compile_deplibs" | $SED 's/ -lc / System.ltframework /'`
-	finalize_deplibs=`$ECHO " $finalize_deplibs" | $SED 's/ -lc / System.ltframework /'`
-	;;
-      esac
-
-      case $host in
-      *-*-darwin*)
-	# Don't allow lazy linking, it breaks C++ global constructors
-	# But is supposedly fixed on 10.4 or later (yay!).
-	if test "$tagname" = CXX ; then
-	  case ${MACOSX_DEPLOYMENT_TARGET-10.0} in
-	    10.[0123])
-	      func_append compile_command " ${wl}-bind_at_load"
-	      func_append finalize_command " ${wl}-bind_at_load"
-	    ;;
-	  esac
-	fi
-	# Time to change all our "foo.ltframework" stuff back to "-framework foo"
-	compile_deplibs=`$ECHO " $compile_deplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
-	finalize_deplibs=`$ECHO " $finalize_deplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
-	;;
-      esac
-
-
-      # move library search paths that coincide with paths to not yet
-      # installed libraries to the beginning of the library search list
-      new_libs=
-      for path in $notinst_path; do
-	case " $new_libs " in
-	*" -L$path/$objdir "*) ;;
-	*)
-	  case " $compile_deplibs " in
-	  *" -L$path/$objdir "*)
-	    func_append new_libs " -L$path/$objdir" ;;
-	  esac
-	  ;;
-	esac
-      done
-      for deplib in $compile_deplibs; do
-	case $deplib in
-	-L*)
-	  case " $new_libs " in
-	  *" $deplib "*) ;;
-	  *) func_append new_libs " $deplib" ;;
-	  esac
-	  ;;
-	*) func_append new_libs " $deplib" ;;
-	esac
-      done
-      compile_deplibs="$new_libs"
-
-
-      func_append compile_command " $compile_deplibs"
-      func_append finalize_command " $finalize_deplibs"
-
-      if test -n "$rpath$xrpath"; then
-	# If the user specified any rpath flags, then add them.
-	for libdir in $rpath $xrpath; do
-	  # This is the magic to use -rpath.
-	  case "$finalize_rpath " in
-	  *" $libdir "*) ;;
-	  *) func_append finalize_rpath " $libdir" ;;
-	  esac
-	done
-      fi
-
-      # Now hardcode the library paths
-      rpath=
-      hardcode_libdirs=
-      for libdir in $compile_rpath $finalize_rpath; do
-	if test -n "$hardcode_libdir_flag_spec"; then
-	  if test -n "$hardcode_libdir_separator"; then
-	    if test -z "$hardcode_libdirs"; then
-	      hardcode_libdirs="$libdir"
-	    else
-	      # Just accumulate the unique libdirs.
-	      case $hardcode_libdir_separator$hardcode_libdirs$hardcode_libdir_separator in
-	      *"$hardcode_libdir_separator$libdir$hardcode_libdir_separator"*)
-		;;
-	      *)
-		func_append hardcode_libdirs "$hardcode_libdir_separator$libdir"
-		;;
-	      esac
-	    fi
-	  else
-	    eval flag=\"$hardcode_libdir_flag_spec\"
-	    func_append rpath " $flag"
-	  fi
-	elif test -n "$runpath_var"; then
-	  case "$perm_rpath " in
-	  *" $libdir "*) ;;
-	  *) func_append perm_rpath " $libdir" ;;
-	  esac
-	fi
-	case $host in
-	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
-	  testbindir=`${ECHO} "$libdir" | ${SED} -e 's*/lib$*/bin*'`
-	  case :$dllsearchpath: in
-	  *":$libdir:"*) ;;
-	  ::) dllsearchpath=$libdir;;
-	  *) func_append dllsearchpath ":$libdir";;
-	  esac
-	  case :$dllsearchpath: in
-	  *":$testbindir:"*) ;;
-	  ::) dllsearchpath=$testbindir;;
-	  *) func_append dllsearchpath ":$testbindir";;
-	  esac
-	  ;;
-	esac
-      done
-      # Substitute the hardcoded libdirs into the rpath.
-      if test -n "$hardcode_libdir_separator" &&
-	 test -n "$hardcode_libdirs"; then
-	libdir="$hardcode_libdirs"
-	eval rpath=\" $hardcode_libdir_flag_spec\"
-      fi
-      compile_rpath="$rpath"
-
-      rpath=
-      hardcode_libdirs=
-      for libdir in $finalize_rpath; do
-	if test -n "$hardcode_libdir_flag_spec"; then
-	  if test -n "$hardcode_libdir_separator"; then
-	    if test -z "$hardcode_libdirs"; then
-	      hardcode_libdirs="$libdir"
-	    else
-	      # Just accumulate the unique libdirs.
-	      case $hardcode_libdir_separator$hardcode_libdirs$hardcode_libdir_separator in
-	      *"$hardcode_libdir_separator$libdir$hardcode_libdir_separator"*)
-		;;
-	      *)
-		func_append hardcode_libdirs "$hardcode_libdir_separator$libdir"
-		;;
-	      esac
-	    fi
-	  else
-	    eval flag=\"$hardcode_libdir_flag_spec\"
-	    func_append rpath " $flag"
-	  fi
-	elif test -n "$runpath_var"; then
-	  case "$finalize_perm_rpath " in
-	  *" $libdir "*) ;;
-	  *) func_append finalize_perm_rpath " $libdir" ;;
-	  esac
-	fi
-      done
-      # Substitute the hardcoded libdirs into the rpath.
-      if test -n "$hardcode_libdir_separator" &&
-	 test -n "$hardcode_libdirs"; then
-	libdir="$hardcode_libdirs"
-	eval rpath=\" $hardcode_libdir_flag_spec\"
-      fi
-      finalize_rpath="$rpath"
-
-      if test -n "$libobjs" && test "$build_old_libs" = yes; then
-	# Transform all the library objects into standard objects.
-	compile_command=`$ECHO "$compile_command" | $SP2NL | $SED "$lo2o" | $NL2SP`
-	finalize_command=`$ECHO "$finalize_command" | $SP2NL | $SED "$lo2o" | $NL2SP`
-      fi
-
-      func_generate_dlsyms "$outputname" "@PROGRAM@" "no"
-
-      # template prelinking step
-      if test -n "$prelink_cmds"; then
-	func_execute_cmds "$prelink_cmds" 'exit $?'
-      fi
-
-      wrappers_required=yes
-      case $host in
-      *cegcc* | *mingw32ce*)
-        # Disable wrappers for cegcc and mingw32ce hosts, we are cross compiling anyway.
-        wrappers_required=no
-        ;;
-      *cygwin* | *mingw* )
-        if test "$build_libtool_libs" != yes; then
-          wrappers_required=no
-        fi
-        ;;
-      *)
-        if test "$need_relink" = no || test "$build_libtool_libs" != yes; then
-          wrappers_required=no
-        fi
-        ;;
-      esac
-      if test "$wrappers_required" = no; then
-	# Replace the output file specification.
-	compile_command=`$ECHO "$compile_command" | $SED 's%@OUTPUT@%'"$output"'%g'`
-	link_command="$compile_command$compile_rpath"
-
-	# We have no uninstalled library dependencies, so finalize right now.
-	exit_status=0
-	func_show_eval "$link_command" 'exit_status=$?'
-
-	if test -n "$postlink_cmds"; then
-	  func_to_tool_file "$output"
-	  postlink_cmds=`func_echo_all "$postlink_cmds" | $SED -e 's%@OUTPUT@%'"$output"'%g' -e 's%@TOOL_OUTPUT@%'"$func_to_tool_file_result"'%g'`
-	  func_execute_cmds "$postlink_cmds" 'exit $?'
-	fi
-
-	# Delete the generated files.
-	if test -f "$output_objdir/${outputname}S.${objext}"; then
-	  func_show_eval '$RM "$output_objdir/${outputname}S.${objext}"'
-	fi
-
-	exit $exit_status
-      fi
-
-      if test -n "$compile_shlibpath$finalize_shlibpath"; then
-	compile_command="$shlibpath_var=\"$compile_shlibpath$finalize_shlibpath\$$shlibpath_var\" $compile_command"
-      fi
-      if test -n "$finalize_shlibpath"; then
-	finalize_command="$shlibpath_var=\"$finalize_shlibpath\$$shlibpath_var\" $finalize_command"
-      fi
-
-      compile_var=
-      finalize_var=
-      if test -n "$runpath_var"; then
-	if test -n "$perm_rpath"; then
-	  # We should set the runpath_var.
-	  rpath=
-	  for dir in $perm_rpath; do
-	    func_append rpath "$dir:"
-	  done
-	  compile_var="$runpath_var=\"$rpath\$$runpath_var\" "
-	fi
-	if test -n "$finalize_perm_rpath"; then
-	  # We should set the runpath_var.
-	  rpath=
-	  for dir in $finalize_perm_rpath; do
-	    func_append rpath "$dir:"
-	  done
-	  finalize_var="$runpath_var=\"$rpath\$$runpath_var\" "
-	fi
-      fi
-
-      if test "$no_install" = yes; then
-	# We don't need to create a wrapper script.
-	link_command="$compile_var$compile_command$compile_rpath"
-	# Replace the output file specification.
-	link_command=`$ECHO "$link_command" | $SED 's%@OUTPUT@%'"$output"'%g'`
-	# Delete the old output file.
-	$opt_dry_run || $RM $output
-	# Link the executable and exit
-	func_show_eval "$link_command" 'exit $?'
-
-	if test -n "$postlink_cmds"; then
-	  func_to_tool_file "$output"
-	  postlink_cmds=`func_echo_all "$postlink_cmds" | $SED -e 's%@OUTPUT@%'"$output"'%g' -e 's%@TOOL_OUTPUT@%'"$func_to_tool_file_result"'%g'`
-	  func_execute_cmds "$postlink_cmds" 'exit $?'
-	fi
-
-	exit $EXIT_SUCCESS
-      fi
-
-      if test "$hardcode_action" = relink; then
-	# Fast installation is not supported
-	link_command="$compile_var$compile_command$compile_rpath"
-	relink_command="$finalize_var$finalize_command$finalize_rpath"
-
-	func_warning "this platform does not like uninstalled shared libraries"
-	func_warning "\`$output' will be relinked during installation"
-      else
-	if test "$fast_install" != no; then
-	  link_command="$finalize_var$compile_command$finalize_rpath"
-	  if test "$fast_install" = yes; then
-	    relink_command=`$ECHO "$compile_var$compile_command$compile_rpath" | $SED 's%@OUTPUT@%\$progdir/\$file%g'`
-	  else
-	    # fast_install is set to needless
-	    relink_command=
-	  fi
-	else
-	  link_command="$compile_var$compile_command$compile_rpath"
-	  relink_command="$finalize_var$finalize_command$finalize_rpath"
-	fi
-      fi
-
-      # Replace the output file specification.
-      link_command=`$ECHO "$link_command" | $SED 's%@OUTPUT@%'"$output_objdir/$outputname"'%g'`
-
-      # Delete the old output files.
-      $opt_dry_run || $RM $output $output_objdir/$outputname $output_objdir/lt-$outputname
-
-      func_show_eval "$link_command" 'exit $?'
-
-      if test -n "$postlink_cmds"; then
-	func_to_tool_file "$output_objdir/$outputname"
-	postlink_cmds=`func_echo_all "$postlink_cmds" | $SED -e 's%@OUTPUT@%'"$output_objdir/$outputname"'%g' -e 's%@TOOL_OUTPUT@%'"$func_to_tool_file_result"'%g'`
-	func_execute_cmds "$postlink_cmds" 'exit $?'
-      fi
-
-      # Now create the wrapper script.
-      func_verbose "creating $output"
-
-      # Quote the relink command for shipping.
-      if test -n "$relink_command"; then
-	# Preserve any variables that may affect compiler behavior
-	for var in $variables_saved_for_relink; do
-	  if eval test -z \"\${$var+set}\"; then
-	    relink_command="{ test -z \"\${$var+set}\" || $lt_unset $var || { $var=; export $var; }; }; $relink_command"
-	  elif eval var_value=\$$var; test -z "$var_value"; then
-	    relink_command="$var=; export $var; $relink_command"
-	  else
-	    func_quote_for_eval "$var_value"
-	    relink_command="$var=$func_quote_for_eval_result; export $var; $relink_command"
-	  fi
-	done
-	relink_command="(cd `pwd`; $relink_command)"
-	relink_command=`$ECHO "$relink_command" | $SED "$sed_quote_subst"`
-      fi
-
-      # Only actually do things if not in dry run mode.
-      $opt_dry_run || {
-	# win32 will think the script is a binary if it has
-	# a .exe suffix, so we strip it off here.
-	case $output in
-	  *.exe) func_stripname '' '.exe' "$output"
-	         output=$func_stripname_result ;;
-	esac
-	# test for cygwin because mv fails w/o .exe extensions
-	case $host in
-	  *cygwin*)
-	    exeext=.exe
-	    func_stripname '' '.exe' "$outputname"
-	    outputname=$func_stripname_result ;;
-	  *) exeext= ;;
-	esac
-	case $host in
-	  *cygwin* | *mingw* )
-	    func_dirname_and_basename "$output" "" "."
-	    output_name=$func_basename_result
-	    output_path=$func_dirname_result
-	    cwrappersource="$output_path/$objdir/lt-$output_name.c"
-	    cwrapper="$output_path/$output_name.exe"
-	    $RM $cwrappersource $cwrapper
-	    trap "$RM $cwrappersource $cwrapper; exit $EXIT_FAILURE" 1 2 15
-
-	    func_emit_cwrapperexe_src > $cwrappersource
-
-	    # The wrapper executable is built using the $host compiler,
-	    # because it contains $host paths and files. If cross-
-	    # compiling, it, like the target executable, must be
-	    # executed on the $host or under an emulation environment.
-	    $opt_dry_run || {
-	      $LTCC $LTCFLAGS -o $cwrapper $cwrappersource
-	      $STRIP $cwrapper
-	    }
-
-	    # Now, create the wrapper script for func_source use:
-	    func_ltwrapper_scriptname $cwrapper
-	    $RM $func_ltwrapper_scriptname_result
-	    trap "$RM $func_ltwrapper_scriptname_result; exit $EXIT_FAILURE" 1 2 15
-	    $opt_dry_run || {
-	      # note: this script will not be executed, so do not chmod.
-	      if test "x$build" = "x$host" ; then
-		$cwrapper --lt-dump-script > $func_ltwrapper_scriptname_result
-	      else
-		func_emit_wrapper no > $func_ltwrapper_scriptname_result
-	      fi
-	    }
-	  ;;
-	  * )
-	    $RM $output
-	    trap "$RM $output; exit $EXIT_FAILURE" 1 2 15
-
-	    func_emit_wrapper no > $output
-	    chmod +x $output
-	  ;;
-	esac
-      }
-      exit $EXIT_SUCCESS
-      ;;
-    esac
-
-    # See if we need to build an old-fashioned archive.
-    for oldlib in $oldlibs; do
-
-      if test "$build_libtool_libs" = convenience; then
-	oldobjs="$libobjs_save $symfileobj"
-	addlibs="$convenience"
-	build_libtool_libs=no
-      else
-	if test "$build_libtool_libs" = module; then
-	  oldobjs="$libobjs_save"
-	  build_libtool_libs=no
-	else
-	  oldobjs="$old_deplibs $non_pic_objects"
-	  if test "$preload" = yes && test -f "$symfileobj"; then
-	    func_append oldobjs " $symfileobj"
-	  fi
-	fi
-	addlibs="$old_convenience"
-      fi
-
-      if test -n "$addlibs"; then
-	gentop="$output_objdir/${outputname}x"
-	func_append generated " $gentop"
-
-	func_extract_archives $gentop $addlibs
-	func_append oldobjs " $func_extract_archives_result"
-      fi
-
-      # Do each command in the archive commands.
-      if test -n "$old_archive_from_new_cmds" && test "$build_libtool_libs" = yes; then
-	cmds=$old_archive_from_new_cmds
-      else
-
-	# Add any objects from preloaded convenience libraries
-	if test -n "$dlprefiles"; then
-	  gentop="$output_objdir/${outputname}x"
-	  func_append generated " $gentop"
-
-	  func_extract_archives $gentop $dlprefiles
-	  func_append oldobjs " $func_extract_archives_result"
-	fi
-
-	# POSIX demands no paths to be encoded in archives.  We have
-	# to avoid creating archives with duplicate basenames if we
-	# might have to extract them afterwards, e.g., when creating a
-	# static archive out of a convenience library, or when linking
-	# the entirety of a libtool archive into another (currently
-	# not supported by libtool).
-	if (for obj in $oldobjs
-	    do
-	      func_basename "$obj"
-	      $ECHO "$func_basename_result"
-	    done | sort | sort -uc >/dev/null 2>&1); then
-	  :
-	else
-	  echo "copying selected object files to avoid basename conflicts..."
-	  gentop="$output_objdir/${outputname}x"
-	  func_append generated " $gentop"
-	  func_mkdir_p "$gentop"
-	  save_oldobjs=$oldobjs
-	  oldobjs=
-	  counter=1
-	  for obj in $save_oldobjs
-	  do
-	    func_basename "$obj"
-	    objbase="$func_basename_result"
-	    case " $oldobjs " in
-	    " ") oldobjs=$obj ;;
-	    *[\ /]"$objbase "*)
-	      while :; do
-		# Make sure we don't pick an alternate name that also
-		# overlaps.
-		newobj=lt$counter-$objbase
-		func_arith $counter + 1
-		counter=$func_arith_result
-		case " $oldobjs " in
-		*[\ /]"$newobj "*) ;;
-		*) if test ! -f "$gentop/$newobj"; then break; fi ;;
-		esac
-	      done
-	      func_show_eval "ln $obj $gentop/$newobj || cp $obj $gentop/$newobj"
-	      func_append oldobjs " $gentop/$newobj"
-	      ;;
-	    *) func_append oldobjs " $obj" ;;
-	    esac
-	  done
-	fi
-	func_to_tool_file "$oldlib" func_convert_file_msys_to_w32
-	tool_oldlib=$func_to_tool_file_result
-	eval cmds=\"$old_archive_cmds\"
-
-	func_len " $cmds"
-	len=$func_len_result
-	if test "$len" -lt "$max_cmd_len" || test "$max_cmd_len" -le -1; then
-	  cmds=$old_archive_cmds
-	elif test -n "$archiver_list_spec"; then
-	  func_verbose "using command file archive linking..."
-	  for obj in $oldobjs
-	  do
-	    func_to_tool_file "$obj"
-	    $ECHO "$func_to_tool_file_result"
-	  done > $output_objdir/$libname.libcmd
-	  func_to_tool_file "$output_objdir/$libname.libcmd"
-	  oldobjs=" $archiver_list_spec$func_to_tool_file_result"
-	  cmds=$old_archive_cmds
-	else
-	  # the command line is too long to link in one step, link in parts
-	  func_verbose "using piecewise archive linking..."
-	  save_RANLIB=$RANLIB
-	  RANLIB=:
-	  objlist=
-	  concat_cmds=
-	  save_oldobjs=$oldobjs
-	  oldobjs=
-	  # Is there a better way of finding the last object in the list?
-	  for obj in $save_oldobjs
-	  do
-	    last_oldobj=$obj
-	  done
-	  eval test_cmds=\"$old_archive_cmds\"
-	  func_len " $test_cmds"
-	  len0=$func_len_result
-	  len=$len0
-	  for obj in $save_oldobjs
-	  do
-	    func_len " $obj"
-	    func_arith $len + $func_len_result
-	    len=$func_arith_result
-	    func_append objlist " $obj"
-	    if test "$len" -lt "$max_cmd_len"; then
-	      :
-	    else
-	      # the above command should be used before it gets too long
-	      oldobjs=$objlist
-	      if test "$obj" = "$last_oldobj" ; then
-		RANLIB=$save_RANLIB
-	      fi
-	      test -z "$concat_cmds" || concat_cmds=$concat_cmds~
-	      eval concat_cmds=\"\${concat_cmds}$old_archive_cmds\"
-	      objlist=
-	      len=$len0
-	    fi
-	  done
-	  RANLIB=$save_RANLIB
-	  oldobjs=$objlist
-	  if test "X$oldobjs" = "X" ; then
-	    eval cmds=\"\$concat_cmds\"
-	  else
-	    eval cmds=\"\$concat_cmds~\$old_archive_cmds\"
-	  fi
-	fi
-      fi
-      func_execute_cmds "$cmds" 'exit $?'
-    done
-
-    test -n "$generated" && \
-      func_show_eval "${RM}r$generated"
-
-    # Now create the libtool archive.
-    case $output in
-    *.la)
-      old_library=
-      test "$build_old_libs" = yes && old_library="$libname.$libext"
-      func_verbose "creating $output"
-
-      # Preserve any variables that may affect compiler behavior
-      for var in $variables_saved_for_relink; do
-	if eval test -z \"\${$var+set}\"; then
-	  relink_command="{ test -z \"\${$var+set}\" || $lt_unset $var || { $var=; export $var; }; }; $relink_command"
-	elif eval var_value=\$$var; test -z "$var_value"; then
-	  relink_command="$var=; export $var; $relink_command"
-	else
-	  func_quote_for_eval "$var_value"
-	  relink_command="$var=$func_quote_for_eval_result; export $var; $relink_command"
-	fi
-      done
-      # Quote the link command for shipping.
-      relink_command="(cd `pwd`; $SHELL $progpath $preserve_args --mode=relink $libtool_args @inst_prefix_dir@)"
-      relink_command=`$ECHO "$relink_command" | $SED "$sed_quote_subst"`
-      if test "$hardcode_automatic" = yes ; then
-	relink_command=
-      fi
-
-      # Only create the output if not a dry run.
-      $opt_dry_run || {
-	for installed in no yes; do
-	  if test "$installed" = yes; then
-	    if test -z "$install_libdir"; then
-	      break
-	    fi
-	    output="$output_objdir/$outputname"i
-	    # Replace all uninstalled libtool libraries with the installed ones
-	    newdependency_libs=
-	    for deplib in $dependency_libs; do
-	      case $deplib in
-	      *.la)
-		func_basename "$deplib"
-		name="$func_basename_result"
-		func_resolve_sysroot "$deplib"
-		eval libdir=`${SED} -n -e 's/^libdir=\(.*\)$/\1/p' $func_resolve_sysroot_result`
-		test -z "$libdir" && \
-		  func_fatal_error "\`$deplib' is not a valid libtool archive"
-		func_append newdependency_libs " ${lt_sysroot:+=}$libdir/$name"
-		;;
-	      -L*)
-		func_stripname -L '' "$deplib"
-		func_replace_sysroot "$func_stripname_result"
-		func_append newdependency_libs " -L$func_replace_sysroot_result"
-		;;
-	      -R*)
-		func_stripname -R '' "$deplib"
-		func_replace_sysroot "$func_stripname_result"
-		func_append newdependency_libs " -R$func_replace_sysroot_result"
-		;;
-	      *) func_append newdependency_libs " $deplib" ;;
-	      esac
-	    done
-	    dependency_libs="$newdependency_libs"
-	    newdlfiles=
-
-	    for lib in $dlfiles; do
-	      case $lib in
-	      *.la)
-	        func_basename "$lib"
-		name="$func_basename_result"
-		eval libdir=`${SED} -n -e 's/^libdir=\(.*\)$/\1/p' $lib`
-		test -z "$libdir" && \
-		  func_fatal_error "\`$lib' is not a valid libtool archive"
-		func_append newdlfiles " ${lt_sysroot:+=}$libdir/$name"
-		;;
-	      *) func_append newdlfiles " $lib" ;;
-	      esac
-	    done
-	    dlfiles="$newdlfiles"
-	    newdlprefiles=
-	    for lib in $dlprefiles; do
-	      case $lib in
-	      *.la)
-		# Only pass preopened files to the pseudo-archive (for
-		# eventual linking with the app. that links it) if we
-		# didn't already link the preopened objects directly into
-		# the library:
-		func_basename "$lib"
-		name="$func_basename_result"
-		eval libdir=`${SED} -n -e 's/^libdir=\(.*\)$/\1/p' $lib`
-		test -z "$libdir" && \
-		  func_fatal_error "\`$lib' is not a valid libtool archive"
-		func_append newdlprefiles " ${lt_sysroot:+=}$libdir/$name"
-		;;
-	      esac
-	    done
-	    dlprefiles="$newdlprefiles"
-	  else
-	    newdlfiles=
-	    for lib in $dlfiles; do
-	      case $lib in
-		[\\/]* | [A-Za-z]:[\\/]*) abs="$lib" ;;
-		*) abs=`pwd`"/$lib" ;;
-	      esac
-	      func_append newdlfiles " $abs"
-	    done
-	    dlfiles="$newdlfiles"
-	    newdlprefiles=
-	    for lib in $dlprefiles; do
-	      case $lib in
-		[\\/]* | [A-Za-z]:[\\/]*) abs="$lib" ;;
-		*) abs=`pwd`"/$lib" ;;
-	      esac
-	      func_append newdlprefiles " $abs"
-	    done
-	    dlprefiles="$newdlprefiles"
-	  fi
-	  $RM $output
-	  # place dlname in correct position for cygwin
-	  # In fact, it would be nice if we could use this code for all target
-	  # systems that can't hard-code library paths into their executables
-	  # and that have no shared library path variable independent of PATH,
-	  # but it turns out we can't easily determine that from inspecting
-	  # libtool variables, so we have to hard-code the OSs to which it
-	  # applies here; at the moment, that means platforms that use the PE
-	  # object format with DLL files.  See the long comment at the top of
-	  # tests/bindir.at for full details.
-	  tdlname=$dlname
-	  case $host,$output,$installed,$module,$dlname in
-	    *cygwin*,*lai,yes,no,*.dll | *mingw*,*lai,yes,no,*.dll | *cegcc*,*lai,yes,no,*.dll)
-	      # If a -bindir argument was supplied, place the dll there.
-	      if test "x$bindir" != x ;
-	      then
-		func_relative_path "$install_libdir" "$bindir"
-		tdlname=$func_relative_path_result$dlname
-	      else
-		# Otherwise fall back on heuristic.
-		tdlname=../bin/$dlname
-	      fi
-	      ;;
-	  esac
-	  $ECHO > $output "\
-# $outputname - a libtool library file
-# Generated by $PROGRAM (GNU $PACKAGE$TIMESTAMP) $VERSION
-#
-# Please DO NOT delete this file!
-# It is necessary for linking the library.
-
-# The name that we can dlopen(3).
-dlname='$tdlname'
-
-# Names of this library.
-library_names='$library_names'
-
-# The name of the static archive.
-old_library='$old_library'
-
-# Linker flags that can not go in dependency_libs.
-inherited_linker_flags='$new_inherited_linker_flags'
-
-# Libraries that this one depends upon.
-dependency_libs='$dependency_libs'
-
-# Names of additional weak libraries provided by this library
-weak_library_names='$weak_libs'
-
-# Version information for $libname.
-current=$current
-age=$age
-revision=$revision
-
-# Is this an already installed library?
-installed=$installed
-
-# Should we warn about portability when linking against -modules?
-shouldnotlink=$module
-
-# Files to dlopen/dlpreopen
-dlopen='$dlfiles'
-dlpreopen='$dlprefiles'
-
-# Directory that this library needs to be installed in:
-libdir='$install_libdir'"
-	  if test "$installed" = no && test "$need_relink" = yes; then
-	    $ECHO >> $output "\
-relink_command=\"$relink_command\""
-	  fi
-	done
-      }
-
-      # Do a symbolic link so that the libtool archive can be found in
-      # LD_LIBRARY_PATH before the program is installed.
-      func_show_eval '( cd "$output_objdir" && $RM "$outputname" && $LN_S "../$outputname" "$outputname" )' 'exit $?'
-      ;;
-    esac
-    exit $EXIT_SUCCESS
-}
-
-{ test "$opt_mode" = link || test "$opt_mode" = relink; } &&
-    func_mode_link ${1+"$@"}
-
-
-# func_mode_uninstall arg...
-func_mode_uninstall ()
-{
-    $opt_debug
-    RM="$nonopt"
-    files=
-    rmforce=
-    exit_status=0
-
-    # This variable tells wrapper scripts just to set variables rather
-    # than running their programs.
-    libtool_install_magic="$magic"
-
-    for arg
-    do
-      case $arg in
-      -f) func_append RM " $arg"; rmforce=yes ;;
-      -*) func_append RM " $arg" ;;
-      *) func_append files " $arg" ;;
-      esac
-    done
-
-    test -z "$RM" && \
-      func_fatal_help "you must specify an RM program"
-
-    rmdirs=
-
-    for file in $files; do
-      func_dirname "$file" "" "."
-      dir="$func_dirname_result"
-      if test "X$dir" = X.; then
-	odir="$objdir"
-      else
-	odir="$dir/$objdir"
-      fi
-      func_basename "$file"
-      name="$func_basename_result"
-      test "$opt_mode" = uninstall && odir="$dir"
-
-      # Remember odir for removal later, being careful to avoid duplicates
-      if test "$opt_mode" = clean; then
-	case " $rmdirs " in
-	  *" $odir "*) ;;
-	  *) func_append rmdirs " $odir" ;;
-	esac
-      fi
-
-      # Don't error if the file doesn't exist and rm -f was used.
-      if { test -L "$file"; } >/dev/null 2>&1 ||
-	 { test -h "$file"; } >/dev/null 2>&1 ||
-	 test -f "$file"; then
-	:
-      elif test -d "$file"; then
-	exit_status=1
-	continue
-      elif test "$rmforce" = yes; then
-	continue
-      fi
-
-      rmfiles="$file"
-
-      case $name in
-      *.la)
-	# Possibly a libtool archive, so verify it.
-	if func_lalib_p "$file"; then
-	  func_source $dir/$name
-
-	  # Delete the libtool libraries and symlinks.
-	  for n in $library_names; do
-	    func_append rmfiles " $odir/$n"
-	  done
-	  test -n "$old_library" && func_append rmfiles " $odir/$old_library"
-
-	  case "$opt_mode" in
-	  clean)
-	    case " $library_names " in
-	    *" $dlname "*) ;;
-	    *) test -n "$dlname" && func_append rmfiles " $odir/$dlname" ;;
-	    esac
-	    test -n "$libdir" && func_append rmfiles " $odir/$name $odir/${name}i"
-	    ;;
-	  uninstall)
-	    if test -n "$library_names"; then
-	      # Do each command in the postuninstall commands.
-	      func_execute_cmds "$postuninstall_cmds" 'test "$rmforce" = yes || exit_status=1'
-	    fi
-
-	    if test -n "$old_library"; then
-	      # Do each command in the old_postuninstall commands.
-	      func_execute_cmds "$old_postuninstall_cmds" 'test "$rmforce" = yes || exit_status=1'
-	    fi
-	    # FIXME: should reinstall the best remaining shared library.
-	    ;;
-	  esac
-	fi
-	;;
-
-      *.lo)
-	# Possibly a libtool object, so verify it.
-	if func_lalib_p "$file"; then
-
-	  # Read the .lo file
-	  func_source $dir/$name
-
-	  # Add PIC object to the list of files to remove.
-	  if test -n "$pic_object" &&
-	     test "$pic_object" != none; then
-	    func_append rmfiles " $dir/$pic_object"
-	  fi
-
-	  # Add non-PIC object to the list of files to remove.
-	  if test -n "$non_pic_object" &&
-	     test "$non_pic_object" != none; then
-	    func_append rmfiles " $dir/$non_pic_object"
-	  fi
-	fi
-	;;
-
-      *)
-	if test "$opt_mode" = clean ; then
-	  noexename=$name
-	  case $file in
-	  *.exe)
-	    func_stripname '' '.exe' "$file"
-	    file=$func_stripname_result
-	    func_stripname '' '.exe' "$name"
-	    noexename=$func_stripname_result
-	    # $file with .exe has already been added to rmfiles,
-	    # add $file without .exe
-	    func_append rmfiles " $file"
-	    ;;
-	  esac
-	  # Do a test to see if this is a libtool program.
-	  if func_ltwrapper_p "$file"; then
-	    if func_ltwrapper_executable_p "$file"; then
-	      func_ltwrapper_scriptname "$file"
-	      relink_command=
-	      func_source $func_ltwrapper_scriptname_result
-	      func_append rmfiles " $func_ltwrapper_scriptname_result"
-	    else
-	      relink_command=
-	      func_source $dir/$noexename
-	    fi
-
-	    # note $name still contains .exe if it was in $file originally
-	    # as does the version of $file that was added into $rmfiles
-	    func_append rmfiles " $odir/$name $odir/${name}S.${objext}"
-	    if test "$fast_install" = yes && test -n "$relink_command"; then
-	      func_append rmfiles " $odir/lt-$name"
-	    fi
-	    if test "X$noexename" != "X$name" ; then
-	      func_append rmfiles " $odir/lt-${noexename}.c"
-	    fi
-	  fi
-	fi
-	;;
-      esac
-      func_show_eval "$RM $rmfiles" 'exit_status=1'
-    done
-
-    # Try to remove the ${objdir}s in the directories where we deleted files
-    for dir in $rmdirs; do
-      if test -d "$dir"; then
-	func_show_eval "rmdir $dir >/dev/null 2>&1"
-      fi
-    done
-
-    exit $exit_status
-}
-
-{ test "$opt_mode" = uninstall || test "$opt_mode" = clean; } &&
-    func_mode_uninstall ${1+"$@"}
-
-test -z "$opt_mode" && {
-  help="$generic_help"
-  func_fatal_help "you must specify a MODE"
-}
-
-test -z "$exec_cmd" && \
-  func_fatal_help "invalid operation mode \`$opt_mode'"
-
-if test -n "$exec_cmd"; then
-  eval exec "$exec_cmd"
-  exit $EXIT_FAILURE
-fi
-
-exit $exit_status
-
-
-# The TAGs below are defined such that we never get into a situation
-# in which we disable both kinds of libraries.  Given conflicting
-# choices, we go for a static library, that is the most portable,
-# since we can't tell whether shared libraries were disabled because
-# the user asked for that or because the platform doesn't support
-# them.  This is particularly important on AIX, because we don't
-# support having both static and shared libraries enabled at the same
-# time on that platform, so we default to a shared-only configuration.
-# If a disable-shared tag is given, we'll fallback to a static-only
-# configuration.  But we'll never go from static-only to shared-only.
-
-# ### BEGIN LIBTOOL TAG CONFIG: disable-shared
-build_libtool_libs=no
-build_old_libs=yes
-# ### END LIBTOOL TAG CONFIG: disable-shared
-
-# ### BEGIN LIBTOOL TAG CONFIG: disable-static
-build_old_libs=`case $build_libtool_libs in yes) echo no;; *) echo yes;; esac`
-# ### END LIBTOOL TAG CONFIG: disable-static
-
-# Local Variables:
-# mode:shell-script
-# sh-indentation:2
-# End:
-# vi:sw=2
-
diff --git a/extern/libpng/include/missing b/extern/libpng/include/missing
deleted file mode 100755
index 28055d2ae6..0000000000
--- a/extern/libpng/include/missing
+++ /dev/null
@@ -1,376 +0,0 @@
-#! /bin/sh
-# Common stub for a few missing GNU programs while installing.
-
-scriptversion=2009-04-28.21; # UTC
-
-# Copyright (C) 1996, 1997, 1999, 2000, 2002, 2003, 2004, 2005, 2006,
-# 2008, 2009 Free Software Foundation, Inc.
-# Originally by Fran,cois Pinard <pinard@iro.umontreal.ca>, 1996.
-
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# As a special exception to the GNU General Public License, if you
-# distribute this file as part of a program that contains a
-# configuration script generated by Autoconf, you may include it under
-# the same distribution terms that you use for the rest of that program.
-
-if test $# -eq 0; then
-  echo 1>&2 "Try \`$0 --help' for more information"
-  exit 1
-fi
-
-run=:
-sed_output='s/.* --output[ =]\([^ ]*\).*/\1/p'
-sed_minuso='s/.* -o \([^ ]*\).*/\1/p'
-
-# In the cases where this matters, `missing' is being run in the
-# srcdir already.
-if test -f configure.ac; then
-  configure_ac=configure.ac
-else
-  configure_ac=configure.in
-fi
-
-msg="missing on your system"
-
-case $1 in
---run)
-  # Try to run requested program, and just exit if it succeeds.
-  run=
-  shift
-  "$@" && exit 0
-  # Exit code 63 means version mismatch.  This often happens
-  # when the user try to use an ancient version of a tool on
-  # a file that requires a minimum version.  In this case we
-  # we should proceed has if the program had been absent, or
-  # if --run hadn't been passed.
-  if test $? = 63; then
-    run=:
-    msg="probably too old"
-  fi
-  ;;
-
-  -h|--h|--he|--hel|--help)
-    echo "\
-$0 [OPTION]... PROGRAM [ARGUMENT]...
-
-Handle \`PROGRAM [ARGUMENT]...' for when PROGRAM is missing, or return an
-error status if there is no known handling for PROGRAM.
-
-Options:
-  -h, --help      display this help and exit
-  -v, --version   output version information and exit
-  --run           try to run the given command, and emulate it if it fails
-
-Supported PROGRAM values:
-  aclocal      touch file \`aclocal.m4'
-  autoconf     touch file \`configure'
-  autoheader   touch file \`config.h.in'
-  autom4te     touch the output file, or create a stub one
-  automake     touch all \`Makefile.in' files
-  bison        create \`y.tab.[ch]', if possible, from existing .[ch]
-  flex         create \`lex.yy.c', if possible, from existing .c
-  help2man     touch the output file
-  lex          create \`lex.yy.c', if possible, from existing .c
-  makeinfo     touch the output file
-  tar          try tar, gnutar, gtar, then tar without non-portable flags
-  yacc         create \`y.tab.[ch]', if possible, from existing .[ch]
-
-Version suffixes to PROGRAM as well as the prefixes \`gnu-', \`gnu', and
-\`g' are ignored when checking the name.
-
-Send bug reports to <bug-automake@gnu.org>."
-    exit $?
-    ;;
-
-  -v|--v|--ve|--ver|--vers|--versi|--versio|--version)
-    echo "missing $scriptversion (GNU Automake)"
-    exit $?
-    ;;
-
-  -*)
-    echo 1>&2 "$0: Unknown \`$1' option"
-    echo 1>&2 "Try \`$0 --help' for more information"
-    exit 1
-    ;;
-
-esac
-
-# normalize program name to check for.
-program=`echo "$1" | sed '
-  s/^gnu-//; t
-  s/^gnu//; t
-  s/^g//; t'`
-
-# Now exit if we have it, but it failed.  Also exit now if we
-# don't have it and --version was passed (most likely to detect
-# the program).  This is about non-GNU programs, so use $1 not
-# $program.
-case $1 in
-  lex*|yacc*)
-    # Not GNU programs, they don't have --version.
-    ;;
-
-  tar*)
-    if test -n "$run"; then
-       echo 1>&2 "ERROR: \`tar' requires --run"
-       exit 1
-    elif test "x$2" = "x--version" || test "x$2" = "x--help"; then
-       exit 1
-    fi
-    ;;
-
-  *)
-    if test -z "$run" && ($1 --version) > /dev/null 2>&1; then
-       # We have it, but it failed.
-       exit 1
-    elif test "x$2" = "x--version" || test "x$2" = "x--help"; then
-       # Could not run --version or --help.  This is probably someone
-       # running `$TOOL --version' or `$TOOL --help' to check whether
-       # $TOOL exists and not knowing $TOOL uses missing.
-       exit 1
-    fi
-    ;;
-esac
-
-# If it does not exist, or fails to run (possibly an outdated version),
-# try to emulate it.
-case $program in
-  aclocal*)
-    echo 1>&2 "\
-WARNING: \`$1' is $msg.  You should only need it if
-         you modified \`acinclude.m4' or \`${configure_ac}'.  You might want
-         to install the \`Automake' and \`Perl' packages.  Grab them from
-         any GNU archive site."
-    touch aclocal.m4
-    ;;
-
-  autoconf*)
-    echo 1>&2 "\
-WARNING: \`$1' is $msg.  You should only need it if
-         you modified \`${configure_ac}'.  You might want to install the
-         \`Autoconf' and \`GNU m4' packages.  Grab them from any GNU
-         archive site."
-    touch configure
-    ;;
-
-  autoheader*)
-    echo 1>&2 "\
-WARNING: \`$1' is $msg.  You should only need it if
-         you modified \`acconfig.h' or \`${configure_ac}'.  You might want
-         to install the \`Autoconf' and \`GNU m4' packages.  Grab them
-         from any GNU archive site."
-    files=`sed -n 's/^[ ]*A[CM]_CONFIG_HEADER(\([^)]*\)).*/\1/p' ${configure_ac}`
-    test -z "$files" && files="config.h"
-    touch_files=
-    for f in $files; do
-      case $f in
-      *:*) touch_files="$touch_files "`echo "$f" |
-				       sed -e 's/^[^:]*://' -e 's/:.*//'`;;
-      *) touch_files="$touch_files $f.in";;
-      esac
-    done
-    touch $touch_files
-    ;;
-
-  automake*)
-    echo 1>&2 "\
-WARNING: \`$1' is $msg.  You should only need it if
-         you modified \`Makefile.am', \`acinclude.m4' or \`${configure_ac}'.
-         You might want to install the \`Automake' and \`Perl' packages.
-         Grab them from any GNU archive site."
-    find . -type f -name Makefile.am -print |
-	   sed 's/\.am$/.in/' |
-	   while read f; do touch "$f"; done
-    ;;
-
-  autom4te*)
-    echo 1>&2 "\
-WARNING: \`$1' is needed, but is $msg.
-         You might have modified some files without having the
-         proper tools for further handling them.
-         You can get \`$1' as part of \`Autoconf' from any GNU
-         archive site."
-
-    file=`echo "$*" | sed -n "$sed_output"`
-    test -z "$file" && file=`echo "$*" | sed -n "$sed_minuso"`
-    if test -f "$file"; then
-	touch $file
-    else
-	test -z "$file" || exec >$file
-	echo "#! /bin/sh"
-	echo "# Created by GNU Automake missing as a replacement of"
-	echo "#  $ $@"
-	echo "exit 0"
-	chmod +x $file
-	exit 1
-    fi
-    ;;
-
-  bison*|yacc*)
-    echo 1>&2 "\
-WARNING: \`$1' $msg.  You should only need it if
-         you modified a \`.y' file.  You may need the \`Bison' package
-         in order for those modifications to take effect.  You can get
-         \`Bison' from any GNU archive site."
-    rm -f y.tab.c y.tab.h
-    if test $# -ne 1; then
-        eval LASTARG="\${$#}"
-	case $LASTARG in
-	*.y)
-	    SRCFILE=`echo "$LASTARG" | sed 's/y$/c/'`
-	    if test -f "$SRCFILE"; then
-	         cp "$SRCFILE" y.tab.c
-	    fi
-	    SRCFILE=`echo "$LASTARG" | sed 's/y$/h/'`
-	    if test -f "$SRCFILE"; then
-	         cp "$SRCFILE" y.tab.h
-	    fi
-	  ;;
-	esac
-    fi
-    if test ! -f y.tab.h; then
-	echo >y.tab.h
-    fi
-    if test ! -f y.tab.c; then
-	echo 'main() { return 0; }' >y.tab.c
-    fi
-    ;;
-
-  lex*|flex*)
-    echo 1>&2 "\
-WARNING: \`$1' is $msg.  You should only need it if
-         you modified a \`.l' file.  You may need the \`Flex' package
-         in order for those modifications to take effect.  You can get
-         \`Flex' from any GNU archive site."
-    rm -f lex.yy.c
-    if test $# -ne 1; then
-        eval LASTARG="\${$#}"
-	case $LASTARG in
-	*.l)
-	    SRCFILE=`echo "$LASTARG" | sed 's/l$/c/'`
-	    if test -f "$SRCFILE"; then
-	         cp "$SRCFILE" lex.yy.c
-	    fi
-	  ;;
-	esac
-    fi
-    if test ! -f lex.yy.c; then
-	echo 'main() { return 0; }' >lex.yy.c
-    fi
-    ;;
-
-  help2man*)
-    echo 1>&2 "\
-WARNING: \`$1' is $msg.  You should only need it if
-	 you modified a dependency of a manual page.  You may need the
-	 \`Help2man' package in order for those modifications to take
-	 effect.  You can get \`Help2man' from any GNU archive site."
-
-    file=`echo "$*" | sed -n "$sed_output"`
-    test -z "$file" && file=`echo "$*" | sed -n "$sed_minuso"`
-    if test -f "$file"; then
-	touch $file
-    else
-	test -z "$file" || exec >$file
-	echo ".ab help2man is required to generate this page"
-	exit $?
-    fi
-    ;;
-
-  makeinfo*)
-    echo 1>&2 "\
-WARNING: \`$1' is $msg.  You should only need it if
-         you modified a \`.texi' or \`.texinfo' file, or any other file
-         indirectly affecting the aspect of the manual.  The spurious
-         call might also be the consequence of using a buggy \`make' (AIX,
-         DU, IRIX).  You might want to install the \`Texinfo' package or
-         the \`GNU make' package.  Grab either from any GNU archive site."
-    # The file to touch is that specified with -o ...
-    file=`echo "$*" | sed -n "$sed_output"`
-    test -z "$file" && file=`echo "$*" | sed -n "$sed_minuso"`
-    if test -z "$file"; then
-      # ... or it is the one specified with @setfilename ...
-      infile=`echo "$*" | sed 's/.* \([^ ]*\) *$/\1/'`
-      file=`sed -n '
-	/^@setfilename/{
-	  s/.* \([^ ]*\) *$/\1/
-	  p
-	  q
-	}' $infile`
-      # ... or it is derived from the source name (dir/f.texi becomes f.info)
-      test -z "$file" && file=`echo "$infile" | sed 's,.*/,,;s,.[^.]*$,,'`.info
-    fi
-    # If the file does not exist, the user really needs makeinfo;
-    # let's fail without touching anything.
-    test -f $file || exit 1
-    touch $file
-    ;;
-
-  tar*)
-    shift
-
-    # We have already tried tar in the generic part.
-    # Look for gnutar/gtar before invocation to avoid ugly error
-    # messages.
-    if (gnutar --version > /dev/null 2>&1); then
-       gnutar "$@" && exit 0
-    fi
-    if (gtar --version > /dev/null 2>&1); then
-       gtar "$@" && exit 0
-    fi
-    firstarg="$1"
-    if shift; then
-	case $firstarg in
-	*o*)
-	    firstarg=`echo "$firstarg" | sed s/o//`
-	    tar "$firstarg" "$@" && exit 0
-	    ;;
-	esac
-	case $firstarg in
-	*h*)
-	    firstarg=`echo "$firstarg" | sed s/h//`
-	    tar "$firstarg" "$@" && exit 0
-	    ;;
-	esac
-    fi
-
-    echo 1>&2 "\
-WARNING: I can't seem to be able to run \`tar' with the given arguments.
-         You may want to install GNU tar or Free paxutils, or check the
-         command line arguments."
-    exit 1
-    ;;
-
-  *)
-    echo 1>&2 "\
-WARNING: \`$1' is needed, and is $msg.
-         You might have modified some files without having the
-         proper tools for further handling them.  Check the \`README' file,
-         it often tells you about the needed prerequisites for installing
-         this package.  You may also peek at any GNU archive site, in case
-         some other package would contain this missing \`$1' program."
-    exit 1
-    ;;
-esac
-
-exit 0
-
-# Local variables:
-# eval: (add-hook 'write-file-hooks 'time-stamp)
-# time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
-# time-stamp-time-zone: "UTC"
-# time-stamp-end: "; # UTC"
-# End:
diff --git a/extern/libpng/include/png.5 b/extern/libpng/include/png.5
deleted file mode 100644
index 34f0e59083..0000000000
--- a/extern/libpng/include/png.5
+++ /dev/null
@@ -1,74 +0,0 @@
-.TH PNG 5 "March 29, 2012"
-.SH NAME
-png \- Portable Network Graphics (PNG) format
-.SH DESCRIPTION
-PNG (Portable Network Graphics) is an extensible file format for the
-lossless, portable, well-compressed storage of raster images. PNG provides
-a patent-free replacement for GIF and can also replace many
-common uses of TIFF. Indexed-color, grayscale, and truecolor images are
-supported, plus an optional alpha channel. Sample depths range from
-1 to 16 bits.
-.br
-
-PNG is designed to work well in online viewing applications, such as the
-World Wide Web, so it is fully streamable with a progressive display
-option. PNG is robust, providing both full file integrity checking and
-fast, simple detection of common transmission errors. Also, PNG can store
-gamma and chromaticity data for improved color matching on heterogeneous
-platforms.
-
-.SH "SEE ALSO"
-.BR "libpng"(3), " libpngpf"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
-.LP
-PNG specification (second edition), November 2003:
-.IP
-.br
-  <http://www.w3.org/TR/2003/REC-PNG-20031110/
-PNG 1.2 specification, July 1999:
-.IP
-.br
-http://www.libpng.org/pub/png
-.LP
-PNG 1.0 specification, October 1996:
-.IP
-.br
-RFC 2083
-.IP
-.br
-ftp://ds.internic.net/rfc/rfc2083.txt
-.br
-or (as a W3C Recommendation) at
-.br
-http://www.w3.org/TR/REC-png.html
-.SH AUTHORS
-This man page: Glenn Randers-Pehrson
-.LP
-Portable Network Graphics (PNG) Specification (Second Edition)
-Information technology - Computer graphics and image processing -
-Portable Network Graphics (PNG): Functional specification.
-ISO/IEC 15948:2003 (E) (November 10, 2003): David Duce and others.
-.LP
-Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999):
-Glenn Randers-Pehrson and others (png-list).
-.LP
-Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996):
-Thomas Boutell and others (png-list).
-.LP
-
-
-.SH COPYRIGHT NOTICE
-.LP
-This man page is Copyright (c) 1998-2006 Glenn Randers-Pehrson.  See png.h
-for conditions of use and distribution.
-.LP
-The PNG Specification (Second Edition) is
-Copyright (c) 2003 W3C. (MIT, ERCIM, Keio), All Rights Reserved.
-.LP
-The PNG-1.2 specification is copyright (c) 1999 Glenn Randers-Pehrson.
-See the specification for conditions of use and distribution.
-.LP
-The PNG-1.0 specification is copyright (c) 1996 Massachusetts Institute of
-Technology.  See the specification for conditions of use and distribution.
-.LP
-.\" end of man page
-
diff --git a/extern/libpng/include/png.c b/extern/libpng/include/png.c
deleted file mode 100644
index cba18ba915..0000000000
--- a/extern/libpng/include/png.c
+++ /dev/null
@@ -1,2874 +0,0 @@
-
-/* png.c - location for general purpose libpng functions
- *
- * Last changed in libpng 1.5.10 [March 8, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#include "pngpriv.h"
-
-/* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_5_10 Your_png_h_is_not_version_1_5_10;
-
-/* Tells libpng that we have already handled the first "num_bytes" bytes
- * of the PNG file signature.  If the PNG data is embedded into another
- * stream we can set num_bytes = 8 so that libpng will not attempt to read
- * or write any of the magic bytes before it starts on the IHDR.
- */
-
-#ifdef PNG_READ_SUPPORTED
-void PNGAPI
-png_set_sig_bytes(png_structp png_ptr, int num_bytes)
-{
-   png_debug(1, "in png_set_sig_bytes");
-
-   if (png_ptr == NULL)
-      return;
-
-   if (num_bytes > 8)
-      png_error(png_ptr, "Too many bytes for PNG signature");
-
-   png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
-}
-
-/* Checks whether the supplied bytes match the PNG signature.  We allow
- * checking less than the full 8-byte signature so that those apps that
- * already read the first few bytes of a file to determine the file type
- * can simply check the remaining bytes for extra assurance.  Returns
- * an integer less than, equal to, or greater than zero if sig is found,
- * respectively, to be less than, to match, or be greater than the correct
- * PNG signature (this is the same behavior as strcmp, memcmp, etc).
- */
-int PNGAPI
-png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
-{
-   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
-
-   if (num_to_check > 8)
-      num_to_check = 8;
-
-   else if (num_to_check < 1)
-      return (-1);
-
-   if (start > 7)
-      return (-1);
-
-   if (start + num_to_check > 8)
-      num_to_check = 8 - start;
-
-   return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
-}
-
-#endif /* PNG_READ_SUPPORTED */
-
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-/* Function to allocate memory for zlib */
-PNG_FUNCTION(voidpf /* PRIVATE */,
-png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
-{
-   png_voidp ptr;
-   png_structp p=(png_structp)png_ptr;
-   png_uint_32 save_flags=p->flags;
-   png_alloc_size_t num_bytes;
-
-   if (png_ptr == NULL)
-      return (NULL);
-
-   if (items > PNG_UINT_32_MAX/size)
-   {
-     png_warning (p, "Potential overflow in png_zalloc()");
-     return (NULL);
-   }
-   num_bytes = (png_alloc_size_t)items * size;
-
-   p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
-   ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
-   p->flags=save_flags;
-
-   return ((voidpf)ptr);
-}
-
-/* Function to free memory for zlib */
-void /* PRIVATE */
-png_zfree(voidpf png_ptr, voidpf ptr)
-{
-   png_free((png_structp)png_ptr, (png_voidp)ptr);
-}
-
-/* Reset the CRC variable to 32 bits of 1's.  Care must be taken
- * in case CRC is > 32 bits to leave the top bits 0.
- */
-void /* PRIVATE */
-png_reset_crc(png_structp png_ptr)
-{
-   /* The cast is safe because the crc is a 32 bit value. */
-   png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
-}
-
-/* Calculate the CRC over a section of data.  We can only pass as
- * much data to this routine as the largest single buffer size.  We
- * also check that this data will actually be used before going to the
- * trouble of calculating it.
- */
-void /* PRIVATE */
-png_calculate_crc(png_structp png_ptr, png_const_bytep ptr, png_size_t length)
-{
-   int need_crc = 1;
-
-   if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name))
-   {
-      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
-          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
-         need_crc = 0;
-   }
-
-   else /* critical */
-   {
-      if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
-         need_crc = 0;
-   }
-
-   /* 'uLong' is defined as unsigned long, this means that on some systems it is
-    * a 64 bit value.  crc32, however, returns 32 bits so the following cast is
-    * safe.  'uInt' may be no more than 16 bits, so it is necessary to perform a
-    * loop here.
-    */
-   if (need_crc && length > 0)
-   {
-      uLong crc = png_ptr->crc; /* Should never issue a warning */
-
-      do
-      {
-         uInt safeLength = (uInt)length;
-         if (safeLength == 0)
-            safeLength = (uInt)-1; /* evil, but safe */
-
-         crc = crc32(crc, ptr, safeLength);
-
-         /* The following should never issue compiler warnings, if they do the
-          * target system has characteristics that will probably violate other
-          * assumptions within the libpng code.
-          */
-         ptr += safeLength;
-         length -= safeLength;
-      }
-      while (length > 0);
-
-      /* And the following is always safe because the crc is only 32 bits. */
-      png_ptr->crc = (png_uint_32)crc;
-   }
-}
-
-/* Check a user supplied version number, called from both read and write
- * functions that create a png_struct
- */
-int
-png_user_version_check(png_structp png_ptr, png_const_charp user_png_ver)
-{
-   if (user_png_ver)
-   {
-      int i = 0;
-
-      do
-      {
-         if (user_png_ver[i] != png_libpng_ver[i])
-            png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
-      } while (png_libpng_ver[i++]);
-   }
-
-   else
-      png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
-
-   if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
-   {
-     /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
-      * we must recompile any applications that use any older library version.
-      * For versions after libpng 1.0, we will be compatible, so we need
-      * only check the first digit.
-      */
-      if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
-          (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
-          (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
-      {
-#ifdef PNG_WARNINGS_SUPPORTED
-         size_t pos = 0;
-         char m[128];
-
-         pos = png_safecat(m, sizeof m, pos, "Application built with libpng-");
-         pos = png_safecat(m, sizeof m, pos, user_png_ver);
-         pos = png_safecat(m, sizeof m, pos, " but running with ");
-         pos = png_safecat(m, sizeof m, pos, png_libpng_ver);
-
-         png_warning(png_ptr, m);
-#endif
-
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
-         png_ptr->flags = 0;
-#endif
-
-         return 0;
-      }
-   }
-
-   /* Success return. */
-   return 1;
-}
-
-/* Allocate the memory for an info_struct for the application.  We don't
- * really need the png_ptr, but it could potentially be useful in the
- * future.  This should be used in favour of malloc(png_sizeof(png_info))
- * and png_info_init() so that applications that want to use a shared
- * libpng don't have to be recompiled if png_info changes size.
- */
-PNG_FUNCTION(png_infop,PNGAPI
-png_create_info_struct,(png_structp png_ptr),PNG_ALLOCATED)
-{
-   png_infop info_ptr;
-
-   png_debug(1, "in png_create_info_struct");
-
-   if (png_ptr == NULL)
-      return (NULL);
-
-#ifdef PNG_USER_MEM_SUPPORTED
-   info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
-      png_ptr->malloc_fn, png_ptr->mem_ptr);
-#else
-   info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
-#endif
-   if (info_ptr != NULL)
-      png_info_init_3(&info_ptr, png_sizeof(png_info));
-
-   return (info_ptr);
-}
-
-/* This function frees the memory associated with a single info struct.
- * Normally, one would use either png_destroy_read_struct() or
- * png_destroy_write_struct() to free an info struct, but this may be
- * useful for some applications.
- */
-void PNGAPI
-png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
-{
-   png_infop info_ptr = NULL;
-
-   png_debug(1, "in png_destroy_info_struct");
-
-   if (png_ptr == NULL)
-      return;
-
-   if (info_ptr_ptr != NULL)
-      info_ptr = *info_ptr_ptr;
-
-   if (info_ptr != NULL)
-   {
-      png_info_destroy(png_ptr, info_ptr);
-
-#ifdef PNG_USER_MEM_SUPPORTED
-      png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
-          png_ptr->mem_ptr);
-#else
-      png_destroy_struct((png_voidp)info_ptr);
-#endif
-      *info_ptr_ptr = NULL;
-   }
-}
-
-/* Initialize the info structure.  This is now an internal function (0.89)
- * and applications using it are urged to use png_create_info_struct()
- * instead.
- */
-
-void PNGAPI
-png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
-{
-   png_infop info_ptr = *ptr_ptr;
-
-   png_debug(1, "in png_info_init_3");
-
-   if (info_ptr == NULL)
-      return;
-
-   if (png_sizeof(png_info) > png_info_struct_size)
-   {
-      png_destroy_struct(info_ptr);
-      info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
-      *ptr_ptr = info_ptr;
-   }
-
-   /* Set everything to 0 */
-   png_memset(info_ptr, 0, png_sizeof(png_info));
-}
-
-void PNGAPI
-png_data_freer(png_structp png_ptr, png_infop info_ptr,
-   int freer, png_uint_32 mask)
-{
-   png_debug(1, "in png_data_freer");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   if (freer == PNG_DESTROY_WILL_FREE_DATA)
-      info_ptr->free_me |= mask;
-
-   else if (freer == PNG_USER_WILL_FREE_DATA)
-      info_ptr->free_me &= ~mask;
-
-   else
-      png_warning(png_ptr,
-         "Unknown freer parameter in png_data_freer");
-}
-
-void PNGAPI
-png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
-   int num)
-{
-   png_debug(1, "in png_free_data");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-#ifdef PNG_TEXT_SUPPORTED
-   /* Free text item num or (if num == -1) all text items */
-   if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
-   {
-      if (num != -1)
-      {
-         if (info_ptr->text && info_ptr->text[num].key)
-         {
-            png_free(png_ptr, info_ptr->text[num].key);
-            info_ptr->text[num].key = NULL;
-         }
-      }
-
-      else
-      {
-         int i;
-         for (i = 0; i < info_ptr->num_text; i++)
-             png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
-         png_free(png_ptr, info_ptr->text);
-         info_ptr->text = NULL;
-         info_ptr->num_text=0;
-      }
-   }
-#endif
-
-#ifdef PNG_tRNS_SUPPORTED
-   /* Free any tRNS entry */
-   if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
-   {
-      png_free(png_ptr, info_ptr->trans_alpha);
-      info_ptr->trans_alpha = NULL;
-      info_ptr->valid &= ~PNG_INFO_tRNS;
-   }
-#endif
-
-#ifdef PNG_sCAL_SUPPORTED
-   /* Free any sCAL entry */
-   if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
-   {
-      png_free(png_ptr, info_ptr->scal_s_width);
-      png_free(png_ptr, info_ptr->scal_s_height);
-      info_ptr->scal_s_width = NULL;
-      info_ptr->scal_s_height = NULL;
-      info_ptr->valid &= ~PNG_INFO_sCAL;
-   }
-#endif
-
-#ifdef PNG_pCAL_SUPPORTED
-   /* Free any pCAL entry */
-   if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
-   {
-      png_free(png_ptr, info_ptr->pcal_purpose);
-      png_free(png_ptr, info_ptr->pcal_units);
-      info_ptr->pcal_purpose = NULL;
-      info_ptr->pcal_units = NULL;
-      if (info_ptr->pcal_params != NULL)
-         {
-            int i;
-            for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
-            {
-               png_free(png_ptr, info_ptr->pcal_params[i]);
-               info_ptr->pcal_params[i] = NULL;
-            }
-            png_free(png_ptr, info_ptr->pcal_params);
-            info_ptr->pcal_params = NULL;
-         }
-      info_ptr->valid &= ~PNG_INFO_pCAL;
-   }
-#endif
-
-#ifdef PNG_iCCP_SUPPORTED
-   /* Free any iCCP entry */
-   if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
-   {
-      png_free(png_ptr, info_ptr->iccp_name);
-      png_free(png_ptr, info_ptr->iccp_profile);
-      info_ptr->iccp_name = NULL;
-      info_ptr->iccp_profile = NULL;
-      info_ptr->valid &= ~PNG_INFO_iCCP;
-   }
-#endif
-
-#ifdef PNG_sPLT_SUPPORTED
-   /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
-   if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
-   {
-      if (num != -1)
-      {
-         if (info_ptr->splt_palettes)
-         {
-            png_free(png_ptr, info_ptr->splt_palettes[num].name);
-            png_free(png_ptr, info_ptr->splt_palettes[num].entries);
-            info_ptr->splt_palettes[num].name = NULL;
-            info_ptr->splt_palettes[num].entries = NULL;
-         }
-      }
-
-      else
-      {
-         if (info_ptr->splt_palettes_num)
-         {
-            int i;
-            for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
-               png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
-
-            png_free(png_ptr, info_ptr->splt_palettes);
-            info_ptr->splt_palettes = NULL;
-            info_ptr->splt_palettes_num = 0;
-         }
-         info_ptr->valid &= ~PNG_INFO_sPLT;
-      }
-   }
-#endif
-
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-   if (png_ptr->unknown_chunk.data)
-   {
-      png_free(png_ptr, png_ptr->unknown_chunk.data);
-      png_ptr->unknown_chunk.data = NULL;
-   }
-
-   if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
-   {
-      if (num != -1)
-      {
-          if (info_ptr->unknown_chunks)
-          {
-             png_free(png_ptr, info_ptr->unknown_chunks[num].data);
-             info_ptr->unknown_chunks[num].data = NULL;
-          }
-      }
-
-      else
-      {
-         int i;
-
-         if (info_ptr->unknown_chunks_num)
-         {
-            for (i = 0; i < info_ptr->unknown_chunks_num; i++)
-               png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
-
-            png_free(png_ptr, info_ptr->unknown_chunks);
-            info_ptr->unknown_chunks = NULL;
-            info_ptr->unknown_chunks_num = 0;
-         }
-      }
-   }
-#endif
-
-#ifdef PNG_hIST_SUPPORTED
-   /* Free any hIST entry */
-   if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
-   {
-      png_free(png_ptr, info_ptr->hist);
-      info_ptr->hist = NULL;
-      info_ptr->valid &= ~PNG_INFO_hIST;
-   }
-#endif
-
-   /* Free any PLTE entry that was internally allocated */
-   if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
-   {
-      png_zfree(png_ptr, info_ptr->palette);
-      info_ptr->palette = NULL;
-      info_ptr->valid &= ~PNG_INFO_PLTE;
-      info_ptr->num_palette = 0;
-   }
-
-#ifdef PNG_INFO_IMAGE_SUPPORTED
-   /* Free any image bits attached to the info structure */
-   if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
-   {
-      if (info_ptr->row_pointers)
-      {
-         int row;
-         for (row = 0; row < (int)info_ptr->height; row++)
-         {
-            png_free(png_ptr, info_ptr->row_pointers[row]);
-            info_ptr->row_pointers[row] = NULL;
-         }
-         png_free(png_ptr, info_ptr->row_pointers);
-         info_ptr->row_pointers = NULL;
-      }
-      info_ptr->valid &= ~PNG_INFO_IDAT;
-   }
-#endif
-
-   if (num != -1)
-      mask &= ~PNG_FREE_MUL;
-
-   info_ptr->free_me &= ~mask;
-}
-
-/* This is an internal routine to free any memory that the info struct is
- * pointing to before re-using it or freeing the struct itself.  Recall
- * that png_free() checks for NULL pointers for us.
- */
-void /* PRIVATE */
-png_info_destroy(png_structp png_ptr, png_infop info_ptr)
-{
-   png_debug(1, "in png_info_destroy");
-
-   png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-   if (png_ptr->num_chunk_list)
-   {
-      png_free(png_ptr, png_ptr->chunk_list);
-      png_ptr->chunk_list = NULL;
-      png_ptr->num_chunk_list = 0;
-   }
-#endif
-
-   png_info_init_3(&info_ptr, png_sizeof(png_info));
-}
-#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
-
-/* This function returns a pointer to the io_ptr associated with the user
- * functions.  The application should free any memory associated with this
- * pointer before png_write_destroy() or png_read_destroy() are called.
- */
-png_voidp PNGAPI
-png_get_io_ptr(png_structp png_ptr)
-{
-   if (png_ptr == NULL)
-      return (NULL);
-
-   return (png_ptr->io_ptr);
-}
-
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-#  ifdef PNG_STDIO_SUPPORTED
-/* Initialize the default input/output functions for the PNG file.  If you
- * use your own read or write routines, you can call either png_set_read_fn()
- * or png_set_write_fn() instead of png_init_io().  If you have defined
- * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
- * function of your own because "FILE *" isn't necessarily available.
- */
-void PNGAPI
-png_init_io(png_structp png_ptr, png_FILE_p fp)
-{
-   png_debug(1, "in png_init_io");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->io_ptr = (png_voidp)fp;
-}
-#  endif
-
-#  ifdef PNG_TIME_RFC1123_SUPPORTED
-/* Convert the supplied time into an RFC 1123 string suitable for use in
- * a "Creation Time" or other text-based time string.
- */
-png_const_charp PNGAPI
-png_convert_to_rfc1123(png_structp png_ptr, png_const_timep ptime)
-{
-   static PNG_CONST char short_months[12][4] =
-        {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
-         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
-
-   if (png_ptr == NULL)
-      return (NULL);
-
-   if (ptime->year > 9999 /* RFC1123 limitation */ ||
-       ptime->month == 0    ||  ptime->month > 12  ||
-       ptime->day   == 0    ||  ptime->day   > 31  ||
-       ptime->hour  > 23    ||  ptime->minute > 59 ||
-       ptime->second > 60)
-   {
-      png_warning(png_ptr, "Ignoring invalid time value");
-      return (NULL);
-   }
-
-   {
-      size_t pos = 0;
-      char number_buf[5]; /* enough for a four-digit year */
-
-#     define APPEND_STRING(string)\
-         pos = png_safecat(png_ptr->time_buffer, sizeof png_ptr->time_buffer,\
-            pos, (string))
-#     define APPEND_NUMBER(format, value)\
-         APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
-#     define APPEND(ch)\
-         if (pos < (sizeof png_ptr->time_buffer)-1)\
-            png_ptr->time_buffer[pos++] = (ch)
-
-      APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
-      APPEND(' ');
-      APPEND_STRING(short_months[(ptime->month - 1)]);
-      APPEND(' ');
-      APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
-      APPEND(' ');
-      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
-      APPEND(':');
-      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
-      APPEND(':');
-      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
-      APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
-
-#     undef APPEND
-#     undef APPEND_NUMBER
-#     undef APPEND_STRING
-   }
-
-   return png_ptr->time_buffer;
-}
-#  endif /* PNG_TIME_RFC1123_SUPPORTED */
-
-#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
-
-png_const_charp PNGAPI
-png_get_copyright(png_const_structp png_ptr)
-{
-   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
-#ifdef PNG_STRING_COPYRIGHT
-   return PNG_STRING_COPYRIGHT
-#else
-#  ifdef __STDC__
-   return PNG_STRING_NEWLINE \
-     "libpng version 1.5.10 - March 29, 2012" PNG_STRING_NEWLINE \
-     "Copyright (c) 1998-2011 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
-     "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
-     "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
-     PNG_STRING_NEWLINE;
-#  else
-      return "libpng version 1.5.10 - March 29, 2012\
-      Copyright (c) 1998-2011 Glenn Randers-Pehrson\
-      Copyright (c) 1996-1997 Andreas Dilger\
-      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
-#  endif
-#endif
-}
-
-/* The following return the library version as a short string in the
- * format 1.0.0 through 99.99.99zz.  To get the version of *.h files
- * used with your application, print out PNG_LIBPNG_VER_STRING, which
- * is defined in png.h.
- * Note: now there is no difference between png_get_libpng_ver() and
- * png_get_header_ver().  Due to the version_nn_nn_nn typedef guard,
- * it is guaranteed that png.c uses the correct version of png.h.
- */
-png_const_charp PNGAPI
-png_get_libpng_ver(png_const_structp png_ptr)
-{
-   /* Version of *.c files used when building libpng */
-   return png_get_header_ver(png_ptr);
-}
-
-png_const_charp PNGAPI
-png_get_header_ver(png_const_structp png_ptr)
-{
-   /* Version of *.h files used when building libpng */
-   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
-   return PNG_LIBPNG_VER_STRING;
-}
-
-png_const_charp PNGAPI
-png_get_header_version(png_const_structp png_ptr)
-{
-   /* Returns longer string containing both version and date */
-   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
-#ifdef __STDC__
-   return PNG_HEADER_VERSION_STRING
-#  ifndef PNG_READ_SUPPORTED
-   "     (NO READ SUPPORT)"
-#  endif
-   PNG_STRING_NEWLINE;
-#else
-   return PNG_HEADER_VERSION_STRING;
-#endif
-}
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-int PNGAPI
-png_handle_as_unknown(png_structp png_ptr, png_const_bytep chunk_name)
-{
-   /* Check chunk_name and return "keep" value if it's on the list, else 0 */
-   png_const_bytep p, p_end;
-
-   if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list <= 0)
-      return PNG_HANDLE_CHUNK_AS_DEFAULT;
-
-   p_end = png_ptr->chunk_list;
-   p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
-
-   /* The code is the fifth byte after each four byte string.  Historically this
-    * code was always searched from the end of the list, so it should continue
-    * to do so in case there are duplicated entries.
-    */
-   do /* num_chunk_list > 0, so at least one */
-   {
-      p -= 5;
-      if (!png_memcmp(chunk_name, p, 4))
-         return p[4];
-   }
-   while (p > p_end);
-
-   return PNG_HANDLE_CHUNK_AS_DEFAULT;
-}
-
-int /* PRIVATE */
-png_chunk_unknown_handling(png_structp png_ptr, png_uint_32 chunk_name)
-{
-   png_byte chunk_string[5];
-
-   PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
-   return png_handle_as_unknown(png_ptr, chunk_string);
-}
-#endif
-
-#ifdef PNG_READ_SUPPORTED
-/* This function, added to libpng-1.0.6g, is untested. */
-int PNGAPI
-png_reset_zstream(png_structp png_ptr)
-{
-   if (png_ptr == NULL)
-      return Z_STREAM_ERROR;
-
-   return (inflateReset(&png_ptr->zstream));
-}
-#endif /* PNG_READ_SUPPORTED */
-
-/* This function was added to libpng-1.0.7 */
-png_uint_32 PNGAPI
-png_access_version_number(void)
-{
-   /* Version of *.c files used when building libpng */
-   return((png_uint_32)PNG_LIBPNG_VER);
-}
-
-
-
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-/* png_convert_size: a PNGAPI but no longer in png.h, so deleted
- * at libpng 1.5.5!
- */
-
-/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
-#  ifdef PNG_CHECK_cHRM_SUPPORTED
-
-int /* PRIVATE */
-png_check_cHRM_fixed(png_structp png_ptr,
-   png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
-   png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
-   png_fixed_point blue_x, png_fixed_point blue_y)
-{
-   int ret = 1;
-   unsigned long xy_hi,xy_lo,yx_hi,yx_lo;
-
-   png_debug(1, "in function png_check_cHRM_fixed");
-
-   if (png_ptr == NULL)
-      return 0;
-
-   /* (x,y,z) values are first limited to 0..100000 (PNG_FP_1), the white
-    * y must also be greater than 0.  To test for the upper limit calculate
-    * (PNG_FP_1-y) - x must be <= to this for z to be >= 0 (and the expression
-    * cannot overflow.)  At this point we know x and y are >= 0 and (x+y) is
-    * <= PNG_FP_1.  The previous test on PNG_MAX_UINT_31 is removed because it
-    * pointless (and it produces compiler warnings!)
-    */
-   if (white_x < 0 || white_y <= 0 ||
-         red_x < 0 ||   red_y <  0 ||
-       green_x < 0 || green_y <  0 ||
-        blue_x < 0 ||  blue_y <  0)
-   {
-      png_warning(png_ptr,
-        "Ignoring attempt to set negative chromaticity value");
-      ret = 0;
-   }
-   /* And (x+y) must be <= PNG_FP_1 (so z is >= 0) */
-   if (white_x > PNG_FP_1 - white_y)
-   {
-      png_warning(png_ptr, "Invalid cHRM white point");
-      ret = 0;
-   }
-
-   if (red_x > PNG_FP_1 - red_y)
-   {
-      png_warning(png_ptr, "Invalid cHRM red point");
-      ret = 0;
-   }
-
-   if (green_x > PNG_FP_1 - green_y)
-   {
-      png_warning(png_ptr, "Invalid cHRM green point");
-      ret = 0;
-   }
-
-   if (blue_x > PNG_FP_1 - blue_y)
-   {
-      png_warning(png_ptr, "Invalid cHRM blue point");
-      ret = 0;
-   }
-
-   png_64bit_product(green_x - red_x, blue_y - red_y, &xy_hi, &xy_lo);
-   png_64bit_product(green_y - red_y, blue_x - red_x, &yx_hi, &yx_lo);
-
-   if (xy_hi == yx_hi && xy_lo == yx_lo)
-   {
-      png_warning(png_ptr,
-         "Ignoring attempt to set cHRM RGB triangle with zero area");
-      ret = 0;
-   }
-
-   return ret;
-}
-#  endif /* PNG_CHECK_cHRM_SUPPORTED */
-
-#ifdef PNG_cHRM_SUPPORTED
-/* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
- * cHRM, as opposed to using chromaticities.  These internal APIs return
- * non-zero on a parameter error.  The X, Y and Z values are required to be
- * positive and less than 1.0.
- */
-int png_xy_from_XYZ(png_xy *xy, png_XYZ XYZ)
-{
-   png_int_32 d, dwhite, whiteX, whiteY;
-
-   d = XYZ.redX + XYZ.redY + XYZ.redZ;
-   if (!png_muldiv(&xy->redx, XYZ.redX, PNG_FP_1, d)) return 1;
-   if (!png_muldiv(&xy->redy, XYZ.redY, PNG_FP_1, d)) return 1;
-   dwhite = d;
-   whiteX = XYZ.redX;
-   whiteY = XYZ.redY;
-
-   d = XYZ.greenX + XYZ.greenY + XYZ.greenZ;
-   if (!png_muldiv(&xy->greenx, XYZ.greenX, PNG_FP_1, d)) return 1;
-   if (!png_muldiv(&xy->greeny, XYZ.greenY, PNG_FP_1, d)) return 1;
-   dwhite += d;
-   whiteX += XYZ.greenX;
-   whiteY += XYZ.greenY;
-
-   d = XYZ.blueX + XYZ.blueY + XYZ.blueZ;
-   if (!png_muldiv(&xy->bluex, XYZ.blueX, PNG_FP_1, d)) return 1;
-   if (!png_muldiv(&xy->bluey, XYZ.blueY, PNG_FP_1, d)) return 1;
-   dwhite += d;
-   whiteX += XYZ.blueX;
-   whiteY += XYZ.blueY;
-
-   /* The reference white is simply the same of the end-point (X,Y,Z) vectors,
-    * thus:
-    */
-   if (!png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite)) return 1;
-   if (!png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite)) return 1;
-
-   return 0;
-}
-
-int png_XYZ_from_xy(png_XYZ *XYZ, png_xy xy)
-{
-   png_fixed_point red_inverse, green_inverse, blue_scale;
-   png_fixed_point left, right, denominator;
-
-   /* Check xy and, implicitly, z.  Note that wide gamut color spaces typically
-    * have end points with 0 tristimulus values (these are impossible end
-    * points, but they are used to cover the possible colors.)
-    */
-   if (xy.redx < 0 || xy.redx > PNG_FP_1) return 1;
-   if (xy.redy < 0 || xy.redy > PNG_FP_1-xy.redx) return 1;
-   if (xy.greenx < 0 || xy.greenx > PNG_FP_1) return 1;
-   if (xy.greeny < 0 || xy.greeny > PNG_FP_1-xy.greenx) return 1;
-   if (xy.bluex < 0 || xy.bluex > PNG_FP_1) return 1;
-   if (xy.bluey < 0 || xy.bluey > PNG_FP_1-xy.bluex) return 1;
-   if (xy.whitex < 0 || xy.whitex > PNG_FP_1) return 1;
-   if (xy.whitey < 0 || xy.whitey > PNG_FP_1-xy.whitex) return 1;
-
-   /* The reverse calculation is more difficult because the original tristimulus
-    * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
-    * derived values were recorded in the cHRM chunk;
-    * (red,green,blue,white)x(x,y).  This loses one degree of freedom and
-    * therefore an arbitrary ninth value has to be introduced to undo the
-    * original transformations.
-    *
-    * Think of the original end-points as points in (X,Y,Z) space.  The
-    * chromaticity values (c) have the property:
-    *
-    *           C
-    *   c = ---------
-    *       X + Y + Z
-    *
-    * For each c (x,y,z) from the corresponding original C (X,Y,Z).  Thus the
-    * three chromaticity values (x,y,z) for each end-point obey the
-    * relationship:
-    *
-    *   x + y + z = 1
-    *
-    * This describes the plane in (X,Y,Z) space that intersects each axis at the
-    * value 1.0; call this the chromaticity plane.  Thus the chromaticity
-    * calculation has scaled each end-point so that it is on the x+y+z=1 plane
-    * and chromaticity is the intersection of the vector from the origin to the
-    * (X,Y,Z) value with the chromaticity plane.
-    *
-    * To fully invert the chromaticity calculation we would need the three
-    * end-point scale factors, (red-scale, green-scale, blue-scale), but these
-    * were not recorded.  Instead we calculated the reference white (X,Y,Z) and
-    * recorded the chromaticity of this.  The reference white (X,Y,Z) would have
-    * given all three of the scale factors since:
-    *
-    *    color-C = color-c * color-scale
-    *    white-C = red-C + green-C + blue-C
-    *            = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
-    *
-    * But cHRM records only white-x and white-y, so we have lost the white scale
-    * factor:
-    *
-    *    white-C = white-c*white-scale
-    *
-    * To handle this the inverse transformation makes an arbitrary assumption
-    * about white-scale:
-    *
-    *    Assume: white-Y = 1.0
-    *    Hence:  white-scale = 1/white-y
-    *    Or:     red-Y + green-Y + blue-Y = 1.0
-    *
-    * Notice the last statement of the assumption gives an equation in three of
-    * the nine values we want to calculate.  8 more equations come from the
-    * above routine as summarised at the top above (the chromaticity
-    * calculation):
-    *
-    *    Given: color-x = color-X / (color-X + color-Y + color-Z)
-    *    Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0
-    *
-    * This is 9 simultaneous equations in the 9 variables "color-C" and can be
-    * solved by Cramer's rule.  Cramer's rule requires calculating 10 9x9 matrix
-    * determinants, however this is not as bad as it seems because only 28 of
-    * the total of 90 terms in the various matrices are non-zero.  Nevertheless
-    * Cramer's rule is notoriously numerically unstable because the determinant
-    * calculation involves the difference of large, but similar, numbers.  It is
-    * difficult to be sure that the calculation is stable for real world values
-    * and it is certain that it becomes unstable where the end points are close
-    * together.
-    *
-    * So this code uses the perhaps slighly less optimal but more understandable
-    * and totally obvious approach of calculating color-scale.
-    *
-    * This algorithm depends on the precision in white-scale and that is
-    * (1/white-y), so we can immediately see that as white-y approaches 0 the
-    * accuracy inherent in the cHRM chunk drops off substantially.
-    *
-    * libpng arithmetic: a simple invertion of the above equations
-    * ------------------------------------------------------------
-    *
-    *    white_scale = 1/white-y
-    *    white-X = white-x * white-scale
-    *    white-Y = 1.0
-    *    white-Z = (1 - white-x - white-y) * white_scale
-    *
-    *    white-C = red-C + green-C + blue-C
-    *            = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
-    *
-    * This gives us three equations in (red-scale,green-scale,blue-scale) where
-    * all the coefficients are now known:
-    *
-    *    red-x*red-scale + green-x*green-scale + blue-x*blue-scale
-    *       = white-x/white-y
-    *    red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1
-    *    red-z*red-scale + green-z*green-scale + blue-z*blue-scale
-    *       = (1 - white-x - white-y)/white-y
-    *
-    * In the last equation color-z is (1 - color-x - color-y) so we can add all
-    * three equations together to get an alternative third:
-    *
-    *    red-scale + green-scale + blue-scale = 1/white-y = white-scale
-    *
-    * So now we have a Cramer's rule solution where the determinants are just
-    * 3x3 - far more tractible.  Unfortunately 3x3 determinants still involve
-    * multiplication of three coefficients so we can't guarantee to avoid
-    * overflow in the libpng fixed point representation.  Using Cramer's rule in
-    * floating point is probably a good choice here, but it's not an option for
-    * fixed point.  Instead proceed to simplify the first two equations by
-    * eliminating what is likely to be the largest value, blue-scale:
-    *
-    *    blue-scale = white-scale - red-scale - green-scale
-    *
-    * Hence:
-    *
-    *    (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale =
-    *                (white-x - blue-x)*white-scale
-    *
-    *    (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale =
-    *                1 - blue-y*white-scale
-    *
-    * And now we can trivially solve for (red-scale,green-scale):
-    *
-    *    green-scale =
-    *                (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale
-    *                -----------------------------------------------------------
-    *                                  green-x - blue-x
-    *
-    *    red-scale =
-    *                1 - blue-y*white-scale - (green-y - blue-y) * green-scale
-    *                ---------------------------------------------------------
-    *                                  red-y - blue-y
-    *
-    * Hence:
-    *
-    *    red-scale =
-    *          ( (green-x - blue-x) * (white-y - blue-y) -
-    *            (green-y - blue-y) * (white-x - blue-x) ) / white-y
-    * -------------------------------------------------------------------------
-    *  (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
-    *
-    *    green-scale =
-    *          ( (red-y - blue-y) * (white-x - blue-x) -
-    *            (red-x - blue-x) * (white-y - blue-y) ) / white-y
-    * -------------------------------------------------------------------------
-    *  (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
-    *
-    * Accuracy:
-    * The input values have 5 decimal digits of accuracy.  The values are all in
-    * the range 0 < value < 1, so simple products are in the same range but may
-    * need up to 10 decimal digits to preserve the original precision and avoid
-    * underflow.  Because we are using a 32-bit signed representation we cannot
-    * match this; the best is a little over 9 decimal digits, less than 10.
-    *
-    * The approach used here is to preserve the maximum precision within the
-    * signed representation.  Because the red-scale calculation above uses the
-    * difference between two products of values that must be in the range -1..+1
-    * it is sufficient to divide the product by 7; ceil(100,000/32767*2).  The
-    * factor is irrelevant in the calculation because it is applied to both
-    * numerator and denominator.
-    *
-    * Note that the values of the differences of the products of the
-    * chromaticities in the above equations tend to be small, for example for
-    * the sRGB chromaticities they are:
-    *
-    * red numerator:    -0.04751
-    * green numerator:  -0.08788
-    * denominator:      -0.2241 (without white-y multiplication)
-    *
-    *  The resultant Y coefficients from the chromaticities of some widely used
-    *  color space definitions are (to 15 decimal places):
-    *
-    *  sRGB
-    *    0.212639005871510 0.715168678767756 0.072192315360734
-    *  Kodak ProPhoto
-    *    0.288071128229293 0.711843217810102 0.000085653960605
-    *  Adobe RGB
-    *    0.297344975250536 0.627363566255466 0.075291458493998
-    *  Adobe Wide Gamut RGB
-    *    0.258728243040113 0.724682314948566 0.016589442011321
-    */
-   /* By the argument, above overflow should be impossible here. The return
-    * value of 2 indicates an internal error to the caller.
-    */
-   if (!png_muldiv(&left, xy.greenx-xy.bluex, xy.redy - xy.bluey, 7)) return 2;
-   if (!png_muldiv(&right, xy.greeny-xy.bluey, xy.redx - xy.bluex, 7)) return 2;
-   denominator = left - right;
-
-   /* Now find the red numerator. */
-   if (!png_muldiv(&left, xy.greenx-xy.bluex, xy.whitey-xy.bluey, 7)) return 2;
-   if (!png_muldiv(&right, xy.greeny-xy.bluey, xy.whitex-xy.bluex, 7)) return 2;
-
-   /* Overflow is possible here and it indicates an extreme set of PNG cHRM
-    * chunk values.  This calculation actually returns the reciprocal of the
-    * scale value because this allows us to delay the multiplication of white-y
-    * into the denominator, which tends to produce a small number.
-    */
-   if (!png_muldiv(&red_inverse, xy.whitey, denominator, left-right) ||
-       red_inverse <= xy.whitey /* r+g+b scales = white scale */)
-      return 1;
-
-   /* Similarly for green_inverse: */
-   if (!png_muldiv(&left, xy.redy-xy.bluey, xy.whitex-xy.bluex, 7)) return 2;
-   if (!png_muldiv(&right, xy.redx-xy.bluex, xy.whitey-xy.bluey, 7)) return 2;
-   if (!png_muldiv(&green_inverse, xy.whitey, denominator, left-right) ||
-       green_inverse <= xy.whitey)
-      return 1;
-
-   /* And the blue scale, the checks above guarantee this can't overflow but it
-    * can still produce 0 for extreme cHRM values.
-    */
-   blue_scale = png_reciprocal(xy.whitey) - png_reciprocal(red_inverse) -
-      png_reciprocal(green_inverse);
-   if (blue_scale <= 0) return 1;
-
-
-   /* And fill in the png_XYZ: */
-   if (!png_muldiv(&XYZ->redX, xy.redx, PNG_FP_1, red_inverse)) return 1;
-   if (!png_muldiv(&XYZ->redY, xy.redy, PNG_FP_1, red_inverse)) return 1;
-   if (!png_muldiv(&XYZ->redZ, PNG_FP_1 - xy.redx - xy.redy, PNG_FP_1,
-      red_inverse))
-      return 1;
-
-   if (!png_muldiv(&XYZ->greenX, xy.greenx, PNG_FP_1, green_inverse)) return 1;
-   if (!png_muldiv(&XYZ->greenY, xy.greeny, PNG_FP_1, green_inverse)) return 1;
-   if (!png_muldiv(&XYZ->greenZ, PNG_FP_1 - xy.greenx - xy.greeny, PNG_FP_1,
-      green_inverse))
-      return 1;
-
-   if (!png_muldiv(&XYZ->blueX, xy.bluex, blue_scale, PNG_FP_1)) return 1;
-   if (!png_muldiv(&XYZ->blueY, xy.bluey, blue_scale, PNG_FP_1)) return 1;
-   if (!png_muldiv(&XYZ->blueZ, PNG_FP_1 - xy.bluex - xy.bluey, blue_scale,
-      PNG_FP_1))
-      return 1;
-
-   return 0; /*success*/
-}
-
-int png_XYZ_from_xy_checked(png_structp png_ptr, png_XYZ *XYZ, png_xy xy)
-{
-   switch (png_XYZ_from_xy(XYZ, xy))
-   {
-      case 0: /* success */
-         return 1;
-
-      case 1:
-         /* The chunk may be technically valid, but we got png_fixed_point
-          * overflow while trying to get XYZ values out of it.  This is
-          * entirely benign - the cHRM chunk is pretty extreme.
-          */
-         png_warning(png_ptr,
-            "extreme cHRM chunk cannot be converted to tristimulus values");
-         break;
-
-      default:
-         /* libpng is broken; this should be a warning but if it happens we
-          * want error reports so for the moment it is an error.
-          */
-         png_error(png_ptr, "internal error in png_XYZ_from_xy");
-         break;
-   }
-
-   /* ERROR RETURN */
-   return 0;
-}
-#endif
-
-void /* PRIVATE */
-png_check_IHDR(png_structp png_ptr,
-   png_uint_32 width, png_uint_32 height, int bit_depth,
-   int color_type, int interlace_type, int compression_type,
-   int filter_type)
-{
-   int error = 0;
-
-   /* Check for width and height valid values */
-   if (width == 0)
-   {
-      png_warning(png_ptr, "Image width is zero in IHDR");
-      error = 1;
-   }
-
-   if (height == 0)
-   {
-      png_warning(png_ptr, "Image height is zero in IHDR");
-      error = 1;
-   }
-
-#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
-   if (width > png_ptr->user_width_max)
-
-#  else
-   if (width > PNG_USER_WIDTH_MAX)
-#  endif
-   {
-      png_warning(png_ptr, "Image width exceeds user limit in IHDR");
-      error = 1;
-   }
-
-#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
-   if (height > png_ptr->user_height_max)
-#  else
-   if (height > PNG_USER_HEIGHT_MAX)
-#  endif
-   {
-      png_warning(png_ptr, "Image height exceeds user limit in IHDR");
-      error = 1;
-   }
-
-   if (width > PNG_UINT_31_MAX)
-   {
-      png_warning(png_ptr, "Invalid image width in IHDR");
-      error = 1;
-   }
-
-   if (height > PNG_UINT_31_MAX)
-   {
-      png_warning(png_ptr, "Invalid image height in IHDR");
-      error = 1;
-   }
-
-   if (width > (PNG_UINT_32_MAX
-                 >> 3)      /* 8-byte RGBA pixels */
-                 - 48       /* bigrowbuf hack */
-                 - 1        /* filter byte */
-                 - 7*8      /* rounding of width to multiple of 8 pixels */
-                 - 8)       /* extra max_pixel_depth pad */
-      png_warning(png_ptr, "Width is too large for libpng to process pixels");
-
-   /* Check other values */
-   if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
-       bit_depth != 8 && bit_depth != 16)
-   {
-      png_warning(png_ptr, "Invalid bit depth in IHDR");
-      error = 1;
-   }
-
-   if (color_type < 0 || color_type == 1 ||
-       color_type == 5 || color_type > 6)
-   {
-      png_warning(png_ptr, "Invalid color type in IHDR");
-      error = 1;
-   }
-
-   if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
-       ((color_type == PNG_COLOR_TYPE_RGB ||
-         color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
-         color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
-   {
-      png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
-      error = 1;
-   }
-
-   if (interlace_type >= PNG_INTERLACE_LAST)
-   {
-      png_warning(png_ptr, "Unknown interlace method in IHDR");
-      error = 1;
-   }
-
-   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
-   {
-      png_warning(png_ptr, "Unknown compression method in IHDR");
-      error = 1;
-   }
-
-#  ifdef PNG_MNG_FEATURES_SUPPORTED
-   /* Accept filter_method 64 (intrapixel differencing) only if
-    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
-    * 2. Libpng did not read a PNG signature (this filter_method is only
-    *    used in PNG datastreams that are embedded in MNG datastreams) and
-    * 3. The application called png_permit_mng_features with a mask that
-    *    included PNG_FLAG_MNG_FILTER_64 and
-    * 4. The filter_method is 64 and
-    * 5. The color_type is RGB or RGBA
-    */
-   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) &&
-       png_ptr->mng_features_permitted)
-      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
-
-   if (filter_type != PNG_FILTER_TYPE_BASE)
-   {
-      if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
-          (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
-          ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
-          (color_type == PNG_COLOR_TYPE_RGB ||
-          color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
-      {
-         png_warning(png_ptr, "Unknown filter method in IHDR");
-         error = 1;
-      }
-
-      if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE)
-      {
-         png_warning(png_ptr, "Invalid filter method in IHDR");
-         error = 1;
-      }
-   }
-
-#  else
-   if (filter_type != PNG_FILTER_TYPE_BASE)
-   {
-      png_warning(png_ptr, "Unknown filter method in IHDR");
-      error = 1;
-   }
-#  endif
-
-   if (error == 1)
-      png_error(png_ptr, "Invalid IHDR data");
-}
-
-#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
-/* ASCII to fp functions */
-/* Check an ASCII formated floating point value, see the more detailed
- * comments in pngpriv.h
- */
-/* The following is used internally to preserve the sticky flags */
-#define png_fp_add(state, flags) ((state) |= (flags))
-#define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY))
-
-int /* PRIVATE */
-png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
-   png_size_tp whereami)
-{
-   int state = *statep;
-   png_size_t i = *whereami;
-
-   while (i < size)
-   {
-      int type;
-      /* First find the type of the next character */
-      switch (string[i])
-      {
-      case 43:  type = PNG_FP_SAW_SIGN;                   break;
-      case 45:  type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break;
-      case 46:  type = PNG_FP_SAW_DOT;                    break;
-      case 48:  type = PNG_FP_SAW_DIGIT;                  break;
-      case 49: case 50: case 51: case 52:
-      case 53: case 54: case 55: case 56:
-      case 57:  type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break;
-      case 69:
-      case 101: type = PNG_FP_SAW_E;                      break;
-      default:  goto PNG_FP_End;
-      }
-
-      /* Now deal with this type according to the current
-       * state, the type is arranged to not overlap the
-       * bits of the PNG_FP_STATE.
-       */
-      switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY))
-      {
-      case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
-         if (state & PNG_FP_SAW_ANY)
-            goto PNG_FP_End; /* not a part of the number */
-
-         png_fp_add(state, type);
-         break;
-
-      case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
-         /* Ok as trailer, ok as lead of fraction. */
-         if (state & PNG_FP_SAW_DOT) /* two dots */
-            goto PNG_FP_End;
-
-         else if (state & PNG_FP_SAW_DIGIT) /* trailing dot? */
-            png_fp_add(state, type);
-
-         else
-            png_fp_set(state, PNG_FP_FRACTION | type);
-
-         break;
-
-      case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
-         if (state & PNG_FP_SAW_DOT) /* delayed fraction */
-            png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);
-
-         png_fp_add(state, type | PNG_FP_WAS_VALID);
-
-         break;
-
-      case PNG_FP_INTEGER + PNG_FP_SAW_E:
-         if ((state & PNG_FP_SAW_DIGIT) == 0)
-            goto PNG_FP_End;
-
-         png_fp_set(state, PNG_FP_EXPONENT);
-
-         break;
-
-   /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN:
-         goto PNG_FP_End; ** no sign in fraction */
-
-   /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT:
-         goto PNG_FP_End; ** Because SAW_DOT is always set */
-
-      case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT:
-         png_fp_add(state, type | PNG_FP_WAS_VALID);
-         break;
-
-      case PNG_FP_FRACTION + PNG_FP_SAW_E:
-         /* This is correct because the trailing '.' on an
-          * integer is handled above - so we can only get here
-          * with the sequence ".E" (with no preceding digits).
-          */
-         if ((state & PNG_FP_SAW_DIGIT) == 0)
-            goto PNG_FP_End;
-
-         png_fp_set(state, PNG_FP_EXPONENT);
-
-         break;
-
-      case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
-         if (state & PNG_FP_SAW_ANY)
-            goto PNG_FP_End; /* not a part of the number */
-
-         png_fp_add(state, PNG_FP_SAW_SIGN);
-
-         break;
-
-   /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT:
-         goto PNG_FP_End; */
-
-      case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT:
-         png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID);
-
-         break;
-
-   /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E:
-         goto PNG_FP_End; */
-
-      default: goto PNG_FP_End; /* I.e. break 2 */
-      }
-
-      /* The character seems ok, continue. */
-      ++i;
-   }
-
-PNG_FP_End:
-   /* Here at the end, update the state and return the correct
-    * return code.
-    */
-   *statep = state;
-   *whereami = i;
-
-   return (state & PNG_FP_SAW_DIGIT) != 0;
-}
-
-
-/* The same but for a complete string. */
-int
-png_check_fp_string(png_const_charp string, png_size_t size)
-{
-   int        state=0;
-   png_size_t char_index=0;
-
-   if (png_check_fp_number(string, size, &state, &char_index) &&
-      (char_index == size || string[char_index] == 0))
-      return state /* must be non-zero - see above */;
-
-   return 0; /* i.e. fail */
-}
-#endif /* pCAL or sCAL */
-
-#ifdef PNG_READ_sCAL_SUPPORTED
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-/* Utility used below - a simple accurate power of ten from an integral
- * exponent.
- */
-static double
-png_pow10(int power)
-{
-   int recip = 0;
-   double d = 1.0;
-
-   /* Handle negative exponent with a reciprocal at the end because
-    * 10 is exact whereas .1 is inexact in base 2
-    */
-   if (power < 0)
-   {
-      if (power < DBL_MIN_10_EXP) return 0;
-      recip = 1, power = -power;
-   }
-
-   if (power > 0)
-   {
-      /* Decompose power bitwise. */
-      double mult = 10.0;
-      do
-      {
-         if (power & 1) d *= mult;
-         mult *= mult;
-         power >>= 1;
-      }
-      while (power > 0);
-
-      if (recip) d = 1/d;
-   }
-   /* else power is 0 and d is 1 */
-
-   return d;
-}
-
-/* Function to format a floating point value in ASCII with a given
- * precision.
- */
-void /* PRIVATE */
-png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size,
-    double fp, unsigned int precision)
-{
-   /* We use standard functions from math.h, but not printf because
-    * that would require stdio.  The caller must supply a buffer of
-    * sufficient size or we will png_error.  The tests on size and
-    * the space in ascii[] consumed are indicated below.
-    */
-   if (precision < 1)
-      precision = DBL_DIG;
-
-   /* Enforce the limit of the implementation precision too. */
-   if (precision > DBL_DIG+1)
-      precision = DBL_DIG+1;
-
-   /* Basic sanity checks */
-   if (size >= precision+5) /* See the requirements below. */
-   {
-      if (fp < 0)
-      {
-         fp = -fp;
-         *ascii++ = 45; /* '-'  PLUS 1 TOTAL 1 */
-         --size;
-      }
-
-      if (fp >= DBL_MIN && fp <= DBL_MAX)
-      {
-         int exp_b10;       /* A base 10 exponent */
-         double base;   /* 10^exp_b10 */
-
-         /* First extract a base 10 exponent of the number,
-          * the calculation below rounds down when converting
-          * from base 2 to base 10 (multiply by log10(2) -
-          * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to
-          * be increased.  Note that the arithmetic shift
-          * performs a floor() unlike C arithmetic - using a
-          * C multiply would break the following for negative
-          * exponents.
-          */
-         (void)frexp(fp, &exp_b10); /* exponent to base 2 */
-
-         exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */
-
-         /* Avoid underflow here. */
-         base = png_pow10(exp_b10); /* May underflow */
-
-         while (base < DBL_MIN || base < fp)
-         {
-            /* And this may overflow. */
-            double test = png_pow10(exp_b10+1);
-
-            if (test <= DBL_MAX)
-               ++exp_b10, base = test;
-
-            else
-               break;
-         }
-
-         /* Normalize fp and correct exp_b10, after this fp is in the
-          * range [.1,1) and exp_b10 is both the exponent and the digit
-          * *before* which the decimal point should be inserted
-          * (starting with 0 for the first digit).  Note that this
-          * works even if 10^exp_b10 is out of range because of the
-          * test on DBL_MAX above.
-          */
-         fp /= base;
-         while (fp >= 1) fp /= 10, ++exp_b10;
-
-         /* Because of the code above fp may, at this point, be
-          * less than .1, this is ok because the code below can
-          * handle the leading zeros this generates, so no attempt
-          * is made to correct that here.
-          */
-
-         {
-            int czero, clead, cdigits;
-            char exponent[10];
-
-            /* Allow up to two leading zeros - this will not lengthen
-             * the number compared to using E-n.
-             */
-            if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */
-            {
-               czero = -exp_b10; /* PLUS 2 digits: TOTAL 3 */
-               exp_b10 = 0;      /* Dot added below before first output. */
-            }
-            else
-               czero = 0;    /* No zeros to add */
-
-            /* Generate the digit list, stripping trailing zeros and
-             * inserting a '.' before a digit if the exponent is 0.
-             */
-            clead = czero; /* Count of leading zeros */
-            cdigits = 0;   /* Count of digits in list. */
-
-            do
-            {
-               double d;
-
-               fp *= 10.0;
-
-               /* Use modf here, not floor and subtract, so that
-                * the separation is done in one step.  At the end
-                * of the loop don't break the number into parts so
-                * that the final digit is rounded.
-                */
-               if (cdigits+czero-clead+1 < (int)precision)
-                  fp = modf(fp, &d);
-
-               else
-               {
-                  d = floor(fp + .5);
-
-                  if (d > 9.0)
-                  {
-                     /* Rounding up to 10, handle that here. */
-                     if (czero > 0)
-                     {
-                        --czero, d = 1;
-                        if (cdigits == 0) --clead;
-                     }
-
-                     else
-                     {
-                        while (cdigits > 0 && d > 9.0)
-                        {
-                           int ch = *--ascii;
-
-                           if (exp_b10 != (-1))
-                              ++exp_b10;
-
-                           else if (ch == 46)
-                           {
-                              ch = *--ascii, ++size;
-                              /* Advance exp_b10 to '1', so that the
-                               * decimal point happens after the
-                               * previous digit.
-                               */
-                              exp_b10 = 1;
-                           }
-
-                           --cdigits;
-                           d = ch - 47;  /* I.e. 1+(ch-48) */
-                        }
-
-                        /* Did we reach the beginning? If so adjust the
-                         * exponent but take into account the leading
-                         * decimal point.
-                         */
-                        if (d > 9.0)  /* cdigits == 0 */
-                        {
-                           if (exp_b10 == (-1))
-                           {
-                              /* Leading decimal point (plus zeros?), if
-                               * we lose the decimal point here it must
-                               * be reentered below.
-                               */
-                              int ch = *--ascii;
-
-                              if (ch == 46)
-                                 ++size, exp_b10 = 1;
-
-                              /* Else lost a leading zero, so 'exp_b10' is
-                               * still ok at (-1)
-                               */
-                           }
-                           else
-                              ++exp_b10;
-
-                           /* In all cases we output a '1' */
-                           d = 1.0;
-                        }
-                     }
-                  }
-                  fp = 0; /* Guarantees termination below. */
-               }
-
-               if (d == 0.0)
-               {
-                  ++czero;
-                  if (cdigits == 0) ++clead;
-               }
-
-               else
-               {
-                  /* Included embedded zeros in the digit count. */
-                  cdigits += czero - clead;
-                  clead = 0;
-
-                  while (czero > 0)
-                  {
-                     /* exp_b10 == (-1) means we just output the decimal
-                      * place - after the DP don't adjust 'exp_b10' any
-                      * more!
-                      */
-                     if (exp_b10 != (-1))
-                     {
-                        if (exp_b10 == 0) *ascii++ = 46, --size;
-                        /* PLUS 1: TOTAL 4 */
-                        --exp_b10;
-                     }
-                     *ascii++ = 48, --czero;
-                  }
-
-                  if (exp_b10 != (-1))
-                  {
-                     if (exp_b10 == 0) *ascii++ = 46, --size; /* counted
-                                                                 above */
-                     --exp_b10;
-                  }
-
-                  *ascii++ = (char)(48 + (int)d), ++cdigits;
-               }
-            }
-            while (cdigits+czero-clead < (int)precision && fp > DBL_MIN);
-
-            /* The total output count (max) is now 4+precision */
-
-            /* Check for an exponent, if we don't need one we are
-             * done and just need to terminate the string.  At
-             * this point exp_b10==(-1) is effectively if flag - it got
-             * to '-1' because of the decrement after outputing
-             * the decimal point above (the exponent required is
-             * *not* -1!)
-             */
-            if (exp_b10 >= (-1) && exp_b10 <= 2)
-            {
-               /* The following only happens if we didn't output the
-                * leading zeros above for negative exponent, so this
-                * doest add to the digit requirement.  Note that the
-                * two zeros here can only be output if the two leading
-                * zeros were *not* output, so this doesn't increase
-                * the output count.
-                */
-               while (--exp_b10 >= 0) *ascii++ = 48;
-
-               *ascii = 0;
-
-               /* Total buffer requirement (including the '\0') is
-                * 5+precision - see check at the start.
-                */
-               return;
-            }
-
-            /* Here if an exponent is required, adjust size for
-             * the digits we output but did not count.  The total
-             * digit output here so far is at most 1+precision - no
-             * decimal point and no leading or trailing zeros have
-             * been output.
-             */
-            size -= cdigits;
-
-            *ascii++ = 69, --size;    /* 'E': PLUS 1 TOTAL 2+precision */
-
-            /* The following use of an unsigned temporary avoids ambiguities in
-             * the signed arithmetic on exp_b10 and permits GCC at least to do
-             * better optimization.
-             */
-            {
-               unsigned int uexp_b10;
-
-               if (exp_b10 < 0)
-               {
-                  *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
-                  uexp_b10 = -exp_b10;
-               }
-
-               else
-                  uexp_b10 = exp_b10;
-
-               cdigits = 0;
-
-               while (uexp_b10 > 0)
-               {
-                  exponent[cdigits++] = (char)(48 + uexp_b10 % 10);
-                  uexp_b10 /= 10;
-               }
-            }
-
-            /* Need another size check here for the exponent digits, so
-             * this need not be considered above.
-             */
-            if ((int)size > cdigits)
-            {
-               while (cdigits > 0) *ascii++ = exponent[--cdigits];
-
-               *ascii = 0;
-
-               return;
-            }
-         }
-      }
-      else if (!(fp >= DBL_MIN))
-      {
-         *ascii++ = 48; /* '0' */
-         *ascii = 0;
-         return;
-      }
-      else
-      {
-         *ascii++ = 105; /* 'i' */
-         *ascii++ = 110; /* 'n' */
-         *ascii++ = 102; /* 'f' */
-         *ascii = 0;
-         return;
-      }
-   }
-
-   /* Here on buffer too small. */
-   png_error(png_ptr, "ASCII conversion buffer too small");
-}
-
-#  endif /* FLOATING_POINT */
-
-#  ifdef PNG_FIXED_POINT_SUPPORTED
-/* Function to format a fixed point value in ASCII.
- */
-void /* PRIVATE */
-png_ascii_from_fixed(png_structp png_ptr, png_charp ascii, png_size_t size,
-    png_fixed_point fp)
-{
-   /* Require space for 10 decimal digits, a decimal point, a minus sign and a
-    * trailing \0, 13 characters:
-    */
-   if (size > 12)
-   {
-      png_uint_32 num;
-
-      /* Avoid overflow here on the minimum integer. */
-      if (fp < 0)
-         *ascii++ = 45, --size, num = -fp;
-      else
-         num = fp;
-
-      if (num <= 0x80000000) /* else overflowed */
-      {
-         unsigned int ndigits = 0, first = 16 /* flag value */;
-         char digits[10];
-
-         while (num)
-         {
-            /* Split the low digit off num: */
-            unsigned int tmp = num/10;
-            num -= tmp*10;
-            digits[ndigits++] = (char)(48 + num);
-            /* Record the first non-zero digit, note that this is a number
-             * starting at 1, it's not actually the array index.
-             */
-            if (first == 16 && num > 0)
-               first = ndigits;
-            num = tmp;
-         }
-
-         if (ndigits > 0)
-         {
-            while (ndigits > 5) *ascii++ = digits[--ndigits];
-            /* The remaining digits are fractional digits, ndigits is '5' or
-             * smaller at this point.  It is certainly not zero.  Check for a
-             * non-zero fractional digit:
-             */
-            if (first <= 5)
-            {
-               unsigned int i;
-               *ascii++ = 46; /* decimal point */
-               /* ndigits may be <5 for small numbers, output leading zeros
-                * then ndigits digits to first:
-                */
-               i = 5;
-               while (ndigits < i) *ascii++ = 48, --i;
-               while (ndigits >= first) *ascii++ = digits[--ndigits];
-               /* Don't output the trailing zeros! */
-            }
-         }
-         else
-            *ascii++ = 48;
-
-         /* And null terminate the string: */
-         *ascii = 0;
-         return;
-      }
-   }
-
-   /* Here on buffer too small. */
-   png_error(png_ptr, "ASCII conversion buffer too small");
-}
-#   endif /* FIXED_POINT */
-#endif /* READ_SCAL */
-
-#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
-   !defined(PNG_FIXED_POINT_MACRO_SUPPORTED)
-png_fixed_point
-png_fixed(png_structp png_ptr, double fp, png_const_charp text)
-{
-   double r = floor(100000 * fp + .5);
-
-   if (r > 2147483647. || r < -2147483648.)
-      png_fixed_error(png_ptr, text);
-
-   return (png_fixed_point)r;
-}
-#endif
-
-#if defined(PNG_READ_GAMMA_SUPPORTED) || \
-    defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG__READ_pHYs_SUPPORTED)
-/* muldiv functions */
-/* This API takes signed arguments and rounds the result to the nearest
- * integer (or, for a fixed point number - the standard argument - to
- * the nearest .00001).  Overflow and divide by zero are signalled in
- * the result, a boolean - true on success, false on overflow.
- */
-int
-png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
-    png_int_32 divisor)
-{
-   /* Return a * times / divisor, rounded. */
-   if (divisor != 0)
-   {
-      if (a == 0 || times == 0)
-      {
-         *res = 0;
-         return 1;
-      }
-      else
-      {
-#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-         double r = a;
-         r *= times;
-         r /= divisor;
-         r = floor(r+.5);
-
-         /* A png_fixed_point is a 32-bit integer. */
-         if (r <= 2147483647. && r >= -2147483648.)
-         {
-            *res = (png_fixed_point)r;
-            return 1;
-         }
-#else
-         int negative = 0;
-         png_uint_32 A, T, D;
-         png_uint_32 s16, s32, s00;
-
-         if (a < 0)
-            negative = 1, A = -a;
-         else
-            A = a;
-
-         if (times < 0)
-            negative = !negative, T = -times;
-         else
-            T = times;
-
-         if (divisor < 0)
-            negative = !negative, D = -divisor;
-         else
-            D = divisor;
-
-         /* Following can't overflow because the arguments only
-          * have 31 bits each, however the result may be 32 bits.
-          */
-         s16 = (A >> 16) * (T & 0xffff) +
-                           (A & 0xffff) * (T >> 16);
-         /* Can't overflow because the a*times bit is only 30
-          * bits at most.
-          */
-         s32 = (A >> 16) * (T >> 16) + (s16 >> 16);
-         s00 = (A & 0xffff) * (T & 0xffff);
-
-         s16 = (s16 & 0xffff) << 16;
-         s00 += s16;
-
-         if (s00 < s16)
-            ++s32; /* carry */
-
-         if (s32 < D) /* else overflow */
-         {
-            /* s32.s00 is now the 64-bit product, do a standard
-             * division, we know that s32 < D, so the maximum
-             * required shift is 31.
-             */
-            int bitshift = 32;
-            png_fixed_point result = 0; /* NOTE: signed */
-
-            while (--bitshift >= 0)
-            {
-               png_uint_32 d32, d00;
-
-               if (bitshift > 0)
-                  d32 = D >> (32-bitshift), d00 = D << bitshift;
-
-               else
-                  d32 = 0, d00 = D;
-
-               if (s32 > d32)
-               {
-                  if (s00 < d00) --s32; /* carry */
-                  s32 -= d32, s00 -= d00, result += 1<<bitshift;
-               }
-
-               else
-                  if (s32 == d32 && s00 >= d00)
-                     s32 = 0, s00 -= d00, result += 1<<bitshift;
-            }
-
-            /* Handle the rounding. */
-            if (s00 >= (D >> 1))
-               ++result;
-
-            if (negative)
-               result = -result;
-
-            /* Check for overflow. */
-            if ((negative && result <= 0) || (!negative && result >= 0))
-            {
-               *res = result;
-               return 1;
-            }
-         }
-#endif
-      }
-   }
-
-   return 0;
-}
-#endif /* READ_GAMMA || INCH_CONVERSIONS */
-
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
-/* The following is for when the caller doesn't much care about the
- * result.
- */
-png_fixed_point
-png_muldiv_warn(png_structp png_ptr, png_fixed_point a, png_int_32 times,
-    png_int_32 divisor)
-{
-   png_fixed_point result;
-
-   if (png_muldiv(&result, a, times, divisor))
-      return result;
-
-   png_warning(png_ptr, "fixed point overflow ignored");
-   return 0;
-}
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED /* more fixed point functions for gammma */
-/* Calculate a reciprocal, return 0 on div-by-zero or overflow. */
-png_fixed_point
-png_reciprocal(png_fixed_point a)
-{
-#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-   double r = floor(1E10/a+.5);
-
-   if (r <= 2147483647. && r >= -2147483648.)
-      return (png_fixed_point)r;
-#else
-   png_fixed_point res;
-
-   if (png_muldiv(&res, 100000, 100000, a))
-      return res;
-#endif
-
-   return 0; /* error/overflow */
-}
-
-/* A local convenience routine. */
-static png_fixed_point
-png_product2(png_fixed_point a, png_fixed_point b)
-{
-   /* The required result is 1/a * 1/b; the following preserves accuracy. */
-#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-   double r = a * 1E-5;
-   r *= b;
-   r = floor(r+.5);
-
-   if (r <= 2147483647. && r >= -2147483648.)
-      return (png_fixed_point)r;
-#else
-   png_fixed_point res;
-
-   if (png_muldiv(&res, a, b, 100000))
-      return res;
-#endif
-
-   return 0; /* overflow */
-}
-
-/* The inverse of the above. */
-png_fixed_point
-png_reciprocal2(png_fixed_point a, png_fixed_point b)
-{
-   /* The required result is 1/a * 1/b; the following preserves accuracy. */
-#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-   double r = 1E15/a;
-   r /= b;
-   r = floor(r+.5);
-
-   if (r <= 2147483647. && r >= -2147483648.)
-      return (png_fixed_point)r;
-#else
-   /* This may overflow because the range of png_fixed_point isn't symmetric,
-    * but this API is only used for the product of file and screen gamma so it
-    * doesn't matter that the smallest number it can produce is 1/21474, not
-    * 1/100000
-    */
-   png_fixed_point res = png_product2(a, b);
-
-   if (res != 0)
-      return png_reciprocal(res);
-#endif
-
-   return 0; /* overflow */
-}
-#endif /* READ_GAMMA */
-
-#ifdef PNG_CHECK_cHRM_SUPPORTED
-/* Added at libpng version 1.2.34 (Dec 8, 2008) and 1.4.0 (Jan 2,
- * 2010: moved from pngset.c) */
-/*
- *    Multiply two 32-bit numbers, V1 and V2, using 32-bit
- *    arithmetic, to produce a 64-bit result in the HI/LO words.
- *
- *                  A B
- *                x C D
- *               ------
- *              AD || BD
- *        AC || CB || 0
- *
- *    where A and B are the high and low 16-bit words of V1,
- *    C and D are the 16-bit words of V2, AD is the product of
- *    A and D, and X || Y is (X << 16) + Y.
-*/
-
-void /* PRIVATE */
-png_64bit_product (long v1, long v2, unsigned long *hi_product,
-    unsigned long *lo_product)
-{
-   int a, b, c, d;
-   long lo, hi, x, y;
-
-   a = (v1 >> 16) & 0xffff;
-   b = v1 & 0xffff;
-   c = (v2 >> 16) & 0xffff;
-   d = v2 & 0xffff;
-
-   lo = b * d;                   /* BD */
-   x = a * d + c * b;            /* AD + CB */
-   y = ((lo >> 16) & 0xffff) + x;
-
-   lo = (lo & 0xffff) | ((y & 0xffff) << 16);
-   hi = (y >> 16) & 0xffff;
-
-   hi += a * c;                  /* AC */
-
-   *hi_product = (unsigned long)hi;
-   *lo_product = (unsigned long)lo;
-}
-#endif /* CHECK_cHRM */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */
-#ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED
-/* Fixed point gamma.
- *
- * To calculate gamma this code implements fast log() and exp() calls using only
- * fixed point arithmetic.  This code has sufficient precision for either 8-bit
- * or 16-bit sample values.
- *
- * The tables used here were calculated using simple 'bc' programs, but C double
- * precision floating point arithmetic would work fine.  The programs are given
- * at the head of each table.
- *
- * 8-bit log table
- *   This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
- *   255, so it's the base 2 logarithm of a normalized 8-bit floating point
- *   mantissa.  The numbers are 32-bit fractions.
- */
-static png_uint_32
-png_8bit_l2[128] =
-{
-#  ifdef PNG_DO_BC
-      for (i=128;i<256;++i) { .5 - l(i/255)/l(2)*65536*65536; }
-#  else
-   4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
-   3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
-   3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
-   3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U,
-   3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U,
-   2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U,
-   2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U,
-   2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U,
-   2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U,
-   2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U,
-   1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U,
-   1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U,
-   1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U,
-   1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U,
-   1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U,
-   971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U,
-   803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U,
-   639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U,
-   479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U,
-   324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
-   172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
-   24347096U, 0U
-#  endif
-
-#if 0
-   /* The following are the values for 16-bit tables - these work fine for the
-    * 8-bit conversions but produce very slightly larger errors in the 16-bit
-    * log (about 1.2 as opposed to 0.7 absolute error in the final value).  To
-    * use these all the shifts below must be adjusted appropriately.
-    */
-   65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
-   57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
-   50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068,
-   43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782,
-   37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887,
-   31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339,
-   25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098,
-   20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132,
-   15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415,
-   10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523,
-   6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495,
-   1119, 744, 372
-#endif
-};
-
-PNG_STATIC png_int_32
-png_log8bit(unsigned int x)
-{
-   unsigned int lg2 = 0;
-   /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log,
-    * because the log is actually negate that means adding 1.  The final
-    * returned value thus has the range 0 (for 255 input) to 7.994 (for 1
-    * input), return 7.99998 for the overflow (log 0) case - so the result is
-    * always at most 19 bits.
-    */
-   if ((x &= 0xff) == 0)
-      return 0xffffffff;
-
-   if ((x & 0xf0) == 0)
-      lg2  = 4, x <<= 4;
-
-   if ((x & 0xc0) == 0)
-      lg2 += 2, x <<= 2;
-
-   if ((x & 0x80) == 0)
-      lg2 += 1, x <<= 1;
-
-   /* result is at most 19 bits, so this cast is safe: */
-   return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16));
-}
-
-/* The above gives exact (to 16 binary places) log2 values for 8-bit images,
- * for 16-bit images we use the most significant 8 bits of the 16-bit value to
- * get an approximation then multiply the approximation by a correction factor
- * determined by the remaining up to 8 bits.  This requires an additional step
- * in the 16-bit case.
- *
- * We want log2(value/65535), we have log2(v'/255), where:
- *
- *    value = v' * 256 + v''
- *          = v' * f
- *
- * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
- * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
- * than 258.  The final factor also needs to correct for the fact that our 8-bit
- * value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
- *
- * This gives a final formula using a calculated value 'x' which is value/v' and
- * scaling by 65536 to match the above table:
- *
- *   log2(x/257) * 65536
- *
- * Since these numbers are so close to '1' we can use simple linear
- * interpolation between the two end values 256/257 (result -368.61) and 258/257
- * (result 367.179).  The values used below are scaled by a further 64 to give
- * 16-bit precision in the interpolation:
- *
- * Start (256): -23591
- * Zero  (257):      0
- * End   (258):  23499
- */
-PNG_STATIC png_int_32
-png_log16bit(png_uint_32 x)
-{
-   unsigned int lg2 = 0;
-
-   /* As above, but now the input has 16 bits. */
-   if ((x &= 0xffff) == 0)
-      return 0xffffffff;
-
-   if ((x & 0xff00) == 0)
-      lg2  = 8, x <<= 8;
-
-   if ((x & 0xf000) == 0)
-      lg2 += 4, x <<= 4;
-
-   if ((x & 0xc000) == 0)
-      lg2 += 2, x <<= 2;
-
-   if ((x & 0x8000) == 0)
-      lg2 += 1, x <<= 1;
-
-   /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
-    * value.
-    */
-   lg2 <<= 28;
-   lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4;
-
-   /* Now we need to interpolate the factor, this requires a division by the top
-    * 8 bits.  Do this with maximum precision.
-    */
-   x = ((x << 16) + (x >> 9)) / (x >> 8);
-
-   /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24,
-    * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly
-    * 16 bits to interpolate to get the low bits of the result.  Round the
-    * answer.  Note that the end point values are scaled by 64 to retain overall
-    * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust
-    * the overall scaling by 6-12.  Round at every step.
-    */
-   x -= 1U << 24;
-
-   if (x <= 65536U) /* <= '257' */
-      lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12);
-
-   else
-      lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12);
-
-   /* Safe, because the result can't have more than 20 bits: */
-   return (png_int_32)((lg2 + 2048) >> 12);
-}
-
-/* The 'exp()' case must invert the above, taking a 20-bit fixed point
- * logarithmic value and returning a 16 or 8-bit number as appropriate.  In
- * each case only the low 16 bits are relevant - the fraction - since the
- * integer bits (the top 4) simply determine a shift.
- *
- * The worst case is the 16-bit distinction between 65535 and 65534, this
- * requires perhaps spurious accuracy in the decoding of the logarithm to
- * distinguish log2(65535/65534.5) - 10^-5 or 17 bits.  There is little chance
- * of getting this accuracy in practice.
- *
- * To deal with this the following exp() function works out the exponent of the
- * frational part of the logarithm by using an accurate 32-bit value from the
- * top four fractional bits then multiplying in the remaining bits.
- */
-static png_uint_32
-png_32bit_exp[16] =
-{
-#  ifdef PNG_DO_BC
-      for (i=0;i<16;++i) { .5 + e(-i/16*l(2))*2^32; }
-#  else
-   /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
-   4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
-   3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
-   2553802834U, 2445529972U, 2341847524U, 2242560872U
-#  endif
-};
-
-/* Adjustment table; provided to explain the numbers in the code below. */
-#ifdef PNG_DO_BC
-for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
-   11 44937.64284865548751208448
-   10 45180.98734845585101160448
-    9 45303.31936980687359311872
-    8 45364.65110595323018870784
-    7 45395.35850361789624614912
-    6 45410.72259715102037508096
-    5 45418.40724413220722311168
-    4 45422.25021786898173001728
-    3 45424.17186732298419044352
-    2 45425.13273269940811464704
-    1 45425.61317555035558641664
-    0 45425.85339951654943850496
-#endif
-
-PNG_STATIC png_uint_32
-png_exp(png_fixed_point x)
-{
-   if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
-   {
-      /* Obtain a 4-bit approximation */
-      png_uint_32 e = png_32bit_exp[(x >> 12) & 0xf];
-
-      /* Incorporate the low 12 bits - these decrease the returned value by
-       * multiplying by a number less than 1 if the bit is set.  The multiplier
-       * is determined by the above table and the shift. Notice that the values
-       * converge on 45426 and this is used to allow linear interpolation of the
-       * low bits.
-       */
-      if (x & 0x800)
-         e -= (((e >> 16) * 44938U) +  16U) >> 5;
-
-      if (x & 0x400)
-         e -= (((e >> 16) * 45181U) +  32U) >> 6;
-
-      if (x & 0x200)
-         e -= (((e >> 16) * 45303U) +  64U) >> 7;
-
-      if (x & 0x100)
-         e -= (((e >> 16) * 45365U) + 128U) >> 8;
-
-      if (x & 0x080)
-         e -= (((e >> 16) * 45395U) + 256U) >> 9;
-
-      if (x & 0x040)
-         e -= (((e >> 16) * 45410U) + 512U) >> 10;
-
-      /* And handle the low 6 bits in a single block. */
-      e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9;
-
-      /* Handle the upper bits of x. */
-      e >>= x >> 16;
-      return e;
-   }
-
-   /* Check for overflow */
-   if (x <= 0)
-      return png_32bit_exp[0];
-
-   /* Else underflow */
-   return 0;
-}
-
-PNG_STATIC png_byte
-png_exp8bit(png_fixed_point lg2)
-{
-   /* Get a 32-bit value: */
-   png_uint_32 x = png_exp(lg2);
-
-   /* Convert the 32-bit value to 0..255 by multiplying by 256-1, note that the
-    * second, rounding, step can't overflow because of the first, subtraction,
-    * step.
-    */
-   x -= x >> 8;
-   return (png_byte)((x + 0x7fffffU) >> 24);
-}
-
-PNG_STATIC png_uint_16
-png_exp16bit(png_fixed_point lg2)
-{
-   /* Get a 32-bit value: */
-   png_uint_32 x = png_exp(lg2);
-
-   /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
-   x -= x >> 16;
-   return (png_uint_16)((x + 32767U) >> 16);
-}
-#endif /* FLOATING_ARITHMETIC */
-
-png_byte
-png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
-{
-   if (value > 0 && value < 255)
-   {
-#     ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-         double r = floor(255*pow(value/255.,gamma_val*.00001)+.5);
-         return (png_byte)r;
-#     else
-         png_int_32 lg2 = png_log8bit(value);
-         png_fixed_point res;
-
-         if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1))
-            return png_exp8bit(res);
-
-         /* Overflow. */
-         value = 0;
-#     endif
-   }
-
-   return (png_byte)value;
-}
-
-png_uint_16
-png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val)
-{
-   if (value > 0 && value < 65535)
-   {
-#     ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-         double r = floor(65535*pow(value/65535.,gamma_val*.00001)+.5);
-         return (png_uint_16)r;
-#     else
-         png_int_32 lg2 = png_log16bit(value);
-         png_fixed_point res;
-
-         if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1))
-            return png_exp16bit(res);
-
-         /* Overflow. */
-         value = 0;
-#     endif
-   }
-
-   return (png_uint_16)value;
-}
-
-/* This does the right thing based on the bit_depth field of the
- * png_struct, interpreting values as 8-bit or 16-bit.  While the result
- * is nominally a 16-bit value if bit depth is 8 then the result is
- * 8-bit (as are the arguments.)
- */
-png_uint_16 /* PRIVATE */
-png_gamma_correct(png_structp png_ptr, unsigned int value,
-    png_fixed_point gamma_val)
-{
-   if (png_ptr->bit_depth == 8)
-      return png_gamma_8bit_correct(value, gamma_val);
-
-   else
-      return png_gamma_16bit_correct(value, gamma_val);
-}
-
-/* This is the shared test on whether a gamma value is 'significant' - whether
- * it is worth doing gamma correction.
- */
-int /* PRIVATE */
-png_gamma_significant(png_fixed_point gamma_val)
-{
-   return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED ||
-       gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
-}
-
-/* Internal function to build a single 16-bit table - the table consists of
- * 'num' 256-entry subtables, where 'num' is determined by 'shift' - the amount
- * to shift the input values right (or 16-number_of_signifiant_bits).
- *
- * The caller is responsible for ensuring that the table gets cleaned up on
- * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument
- * should be somewhere that will be cleaned.
- */
-static void
-png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable,
-   PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
-{
-   /* Various values derived from 'shift': */
-   PNG_CONST unsigned int num = 1U << (8U - shift);
-   PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
-   PNG_CONST unsigned int max_by_2 = 1U << (15U-shift);
-   unsigned int i;
-
-   png_uint_16pp table = *ptable =
-       (png_uint_16pp)png_calloc(png_ptr, num * png_sizeof(png_uint_16p));
-
-   for (i = 0; i < num; i++)
-   {
-      png_uint_16p sub_table = table[i] =
-          (png_uint_16p)png_malloc(png_ptr, 256 * png_sizeof(png_uint_16));
-
-      /* The 'threshold' test is repeated here because it can arise for one of
-       * the 16-bit tables even if the others don't hit it.
-       */
-      if (png_gamma_significant(gamma_val))
-      {
-         /* The old code would overflow at the end and this would cause the
-          * 'pow' function to return a result >1, resulting in an
-          * arithmetic error.  This code follows the spec exactly; ig is
-          * the recovered input sample, it always has 8-16 bits.
-          *
-          * We want input * 65535/max, rounded, the arithmetic fits in 32
-          * bits (unsigned) so long as max <= 32767.
-          */
-         unsigned int j;
-         for (j = 0; j < 256; j++)
-         {
-            png_uint_32 ig = (j << (8-shift)) + i;
-#           ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-               /* Inline the 'max' scaling operation: */
-               double d = floor(65535*pow(ig/(double)max, gamma_val*.00001)+.5);
-               sub_table[j] = (png_uint_16)d;
-#           else
-               if (shift)
-                  ig = (ig * 65535U + max_by_2)/max;
-
-               sub_table[j] = png_gamma_16bit_correct(ig, gamma_val);
-#           endif
-         }
-      }
-      else
-      {
-         /* We must still build a table, but do it the fast way. */
-         unsigned int j;
-
-         for (j = 0; j < 256; j++)
-         {
-            png_uint_32 ig = (j << (8-shift)) + i;
-
-            if (shift)
-               ig = (ig * 65535U + max_by_2)/max;
-
-            sub_table[j] = (png_uint_16)ig;
-         }
-      }
-   }
-}
-
-/* NOTE: this function expects the *inverse* of the overall gamma transformation
- * required.
- */
-static void
-png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable,
-   PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
-{
-   PNG_CONST unsigned int num = 1U << (8U - shift);
-   PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
-   unsigned int i;
-   png_uint_32 last;
-
-   png_uint_16pp table = *ptable =
-       (png_uint_16pp)png_calloc(png_ptr, num * png_sizeof(png_uint_16p));
-
-   /* 'num' is the number of tables and also the number of low bits of the
-    * input 16-bit value used to select a table.  Each table is itself indexed
-    * by the high 8 bits of the value.
-    */
-   for (i = 0; i < num; i++)
-      table[i] = (png_uint_16p)png_malloc(png_ptr,
-          256 * png_sizeof(png_uint_16));
-
-   /* 'gamma_val' is set to the reciprocal of the value calculated above, so
-    * pow(out,g) is an *input* value.  'last' is the last input value set.
-    *
-    * In the loop 'i' is used to find output values.  Since the output is
-    * 8-bit there are only 256 possible values.  The tables are set up to
-    * select the closest possible output value for each input by finding
-    * the input value at the boundary between each pair of output values
-    * and filling the table up to that boundary with the lower output
-    * value.
-    *
-    * The boundary values are 0.5,1.5..253.5,254.5.  Since these are 9-bit
-    * values the code below uses a 16-bit value in i; the values start at
-    * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
-    * entries are filled with 255).  Start i at 128 and fill all 'last'
-    * table entries <= 'max'
-    */
-   last = 0;
-   for (i = 0; i < 255; ++i) /* 8-bit output value */
-   {
-      /* Find the corresponding maximum input value */
-      png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */
-
-      /* Find the boundary value in 16 bits: */
-      png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val);
-
-      /* Adjust (round) to (16-shift) bits: */
-      bound = (bound * max + 32768U)/65535U + 1U;
-
-      while (last < bound)
-      {
-         table[last & (0xffU >> shift)][last >> (8U - shift)] = out;
-         last++;
-      }
-   }
-
-   /* And fill in the final entries. */
-   while (last < (num << 8))
-   {
-      table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U;
-      last++;
-   }
-}
-
-/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
- * typically much faster).  Note that libpng currently does no sBIT processing
- * (apparently contrary to the spec) so a 256-entry table is always generated.
- */
-static void
-png_build_8bit_table(png_structp png_ptr, png_bytepp ptable,
-   PNG_CONST png_fixed_point gamma_val)
-{
-   unsigned int i;
-   png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256);
-
-   if (png_gamma_significant(gamma_val)) for (i=0; i<256; i++)
-      table[i] = png_gamma_8bit_correct(i, gamma_val);
-
-   else for (i=0; i<256; ++i)
-      table[i] = (png_byte)i;
-}
-
-/* Used from png_read_destroy and below to release the memory used by the gamma
- * tables.
- */
-void /* PRIVATE */
-png_destroy_gamma_table(png_structp png_ptr)
-{
-   png_free(png_ptr, png_ptr->gamma_table);
-   png_ptr->gamma_table = NULL;
-
-   if (png_ptr->gamma_16_table != NULL)
-   {
-      int i;
-      int istop = (1 << (8 - png_ptr->gamma_shift));
-      for (i = 0; i < istop; i++)
-      {
-         png_free(png_ptr, png_ptr->gamma_16_table[i]);
-      }
-   png_free(png_ptr, png_ptr->gamma_16_table);
-   png_ptr->gamma_16_table = NULL;
-   }
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
-   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-   png_free(png_ptr, png_ptr->gamma_from_1);
-   png_ptr->gamma_from_1 = NULL;
-   png_free(png_ptr, png_ptr->gamma_to_1);
-   png_ptr->gamma_to_1 = NULL;
-
-   if (png_ptr->gamma_16_from_1 != NULL)
-   {
-      int i;
-      int istop = (1 << (8 - png_ptr->gamma_shift));
-      for (i = 0; i < istop; i++)
-      {
-         png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
-      }
-   png_free(png_ptr, png_ptr->gamma_16_from_1);
-   png_ptr->gamma_16_from_1 = NULL;
-   }
-   if (png_ptr->gamma_16_to_1 != NULL)
-   {
-      int i;
-      int istop = (1 << (8 - png_ptr->gamma_shift));
-      for (i = 0; i < istop; i++)
-      {
-         png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
-      }
-   png_free(png_ptr, png_ptr->gamma_16_to_1);
-   png_ptr->gamma_16_to_1 = NULL;
-   }
-#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
-}
-
-/* We build the 8- or 16-bit gamma tables here.  Note that for 16-bit
- * tables, we don't make a full table if we are reducing to 8-bit in
- * the future.  Note also how the gamma_16 tables are segmented so that
- * we don't need to allocate > 64K chunks for a full 16-bit table.
- */
-void /* PRIVATE */
-png_build_gamma_table(png_structp png_ptr, int bit_depth)
-{
-  png_debug(1, "in png_build_gamma_table");
-
-  /* Remove any existing table; this copes with multiple calls to
-   * png_read_update_info.  The warning is because building the gamma tables
-   * multiple times is a performance hit - it's harmless but the ability to call
-   * png_read_update_info() multiple times is new in 1.5.6 so it seems sensible
-   * to warn if the app introduces such a hit.
-   */
-  if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL)
-  {
-    png_warning(png_ptr, "gamma table being rebuilt");
-    png_destroy_gamma_table(png_ptr);
-  }
-
-  if (bit_depth <= 8)
-  {
-     png_build_8bit_table(png_ptr, &png_ptr->gamma_table,
-         png_ptr->screen_gamma > 0 ?  png_reciprocal2(png_ptr->gamma,
-         png_ptr->screen_gamma) : PNG_FP_1);
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
-   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-     if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
-     {
-        png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
-            png_reciprocal(png_ptr->gamma));
-
-        png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1,
-            png_ptr->screen_gamma > 0 ?  png_reciprocal(png_ptr->screen_gamma) :
-            png_ptr->gamma/* Probably doing rgb_to_gray */);
-     }
-#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
-  }
-  else
-  {
-     png_byte shift, sig_bit;
-
-     if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
-     {
-        sig_bit = png_ptr->sig_bit.red;
-
-        if (png_ptr->sig_bit.green > sig_bit)
-           sig_bit = png_ptr->sig_bit.green;
-
-        if (png_ptr->sig_bit.blue > sig_bit)
-           sig_bit = png_ptr->sig_bit.blue;
-     }
-     else
-        sig_bit = png_ptr->sig_bit.gray;
-
-     /* 16-bit gamma code uses this equation:
-      *
-      *   ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
-      *
-      * Where 'iv' is the input color value and 'ov' is the output value -
-      * pow(iv, gamma).
-      *
-      * Thus the gamma table consists of up to 256 256-entry tables.  The table
-      * is selected by the (8-gamma_shift) most significant of the low 8 bits of
-      * the color value then indexed by the upper 8 bits:
-      *
-      *   table[low bits][high 8 bits]
-      *
-      * So the table 'n' corresponds to all those 'iv' of:
-      *
-      *   <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
-      *
-      */
-     if (sig_bit > 0 && sig_bit < 16U)
-        shift = (png_byte)(16U - sig_bit); /* shift == insignificant bits */
-
-     else
-        shift = 0; /* keep all 16 bits */
-
-     if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
-     {
-        /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
-         * the significant bits in the *input* when the output will
-         * eventually be 8 bits.  By default it is 11.
-         */
-        if (shift < (16U - PNG_MAX_GAMMA_8))
-           shift = (16U - PNG_MAX_GAMMA_8);
-     }
-
-     if (shift > 8U)
-        shift = 8U; /* Guarantees at least one table! */
-
-     png_ptr->gamma_shift = shift;
-
-#ifdef PNG_16BIT_SUPPORTED
-     /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now
-      * PNG_COMPOSE).  This effectively smashed the background calculation for
-      * 16-bit output because the 8-bit table assumes the result will be reduced
-      * to 8 bits.
-      */
-     if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
-#endif
-         png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
-         png_ptr->screen_gamma > 0 ? png_product2(png_ptr->gamma,
-         png_ptr->screen_gamma) : PNG_FP_1);
-
-#ifdef PNG_16BIT_SUPPORTED
-     else
-         png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift,
-         png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->gamma,
-         png_ptr->screen_gamma) : PNG_FP_1);
-#endif
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
-   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-     if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
-     {
-        png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
-            png_reciprocal(png_ptr->gamma));
-
-        /* Notice that the '16 from 1' table should be full precision, however
-         * the lookup on this table still uses gamma_shift, so it can't be.
-         * TODO: fix this.
-         */
-        png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift,
-            png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
-            png_ptr->gamma/* Probably doing rgb_to_gray */);
-     }
-#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
-  }
-}
-#endif /* READ_GAMMA */
-#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
diff --git a/extern/libpng/include/png.h b/extern/libpng/include/png.h
deleted file mode 100644
index 4e0dee1793..0000000000
--- a/extern/libpng/include/png.h
+++ /dev/null
@@ -1,2666 +0,0 @@
-
-/* png.h - header file for PNG reference library
- *
- * libpng version 1.5.10 - March 29, 2012
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license (See LICENSE, below)
- *
- * Authors and maintainers:
- *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
- *   libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.5.10 - March 29, 2012: Glenn
- *   See also "Contributing Authors", below.
- *
- * Note about libpng version numbers:
- *
- *   Due to various miscommunications, unforeseen code incompatibilities
- *   and occasional factors outside the authors' control, version numbering
- *   on the library has not always been consistent and straightforward.
- *   The following table summarizes matters since version 0.89c, which was
- *   the first widely used release:
- *
- *    source                 png.h  png.h  shared-lib
- *    version                string   int  version
- *    -------                ------ -----  ----------
- *    0.89c "1.0 beta 3"     0.89      89  1.0.89
- *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
- *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
- *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
- *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
- *    0.97c                  0.97      97  2.0.97
- *    0.98                   0.98      98  2.0.98
- *    0.99                   0.99      98  2.0.99
- *    0.99a-m                0.99      99  2.0.99
- *    1.00                   1.00     100  2.1.0 [100 should be 10000]
- *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
- *    1.0.1       png.h string is   10001  2.1.0
- *    1.0.1a-e    identical to the  10002  from here on, the shared library
- *    1.0.2       source version)   10002  is 2.V where V is the source code
- *    1.0.2a-b                      10003  version, except as noted.
- *    1.0.3                         10003
- *    1.0.3a-d                      10004
- *    1.0.4                         10004
- *    1.0.4a-f                      10005
- *    1.0.5 (+ 2 patches)           10005
- *    1.0.5a-d                      10006
- *    1.0.5e-r                      10100 (not source compatible)
- *    1.0.5s-v                      10006 (not binary compatible)
- *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)
- *    1.0.6d-f                      10007 (still binary incompatible)
- *    1.0.6g                        10007
- *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)
- *    1.0.6i                        10007  10.6i
- *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
- *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
- *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
- *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
- *    1.0.7                    1    10007  (still compatible)
- *    1.0.8beta1-4             1    10008  2.1.0.8beta1-4
- *    1.0.8rc1                 1    10008  2.1.0.8rc1
- *    1.0.8                    1    10008  2.1.0.8
- *    1.0.9beta1-6             1    10009  2.1.0.9beta1-6
- *    1.0.9rc1                 1    10009  2.1.0.9rc1
- *    1.0.9beta7-10            1    10009  2.1.0.9beta7-10
- *    1.0.9rc2                 1    10009  2.1.0.9rc2
- *    1.0.9                    1    10009  2.1.0.9
- *    1.0.10beta1              1    10010  2.1.0.10beta1
- *    1.0.10rc1                1    10010  2.1.0.10rc1
- *    1.0.10                   1    10010  2.1.0.10
- *    1.0.11beta1-3            1    10011  2.1.0.11beta1-3
- *    1.0.11rc1                1    10011  2.1.0.11rc1
- *    1.0.11                   1    10011  2.1.0.11
- *    1.0.12beta1-2            2    10012  2.1.0.12beta1-2
- *    1.0.12rc1                2    10012  2.1.0.12rc1
- *    1.0.12                   2    10012  2.1.0.12
- *    1.1.0a-f                 -    10100  2.1.1.0a-f (branch abandoned)
- *    1.2.0beta1-2             2    10200  2.1.2.0beta1-2
- *    1.2.0beta3-5             3    10200  3.1.2.0beta3-5
- *    1.2.0rc1                 3    10200  3.1.2.0rc1
- *    1.2.0                    3    10200  3.1.2.0
- *    1.2.1beta1-4             3    10201  3.1.2.1beta1-4
- *    1.2.1rc1-2               3    10201  3.1.2.1rc1-2
- *    1.2.1                    3    10201  3.1.2.1
- *    1.2.2beta1-6            12    10202  12.so.0.1.2.2beta1-6
- *    1.0.13beta1             10    10013  10.so.0.1.0.13beta1
- *    1.0.13rc1               10    10013  10.so.0.1.0.13rc1
- *    1.2.2rc1                12    10202  12.so.0.1.2.2rc1
- *    1.0.13                  10    10013  10.so.0.1.0.13
- *    1.2.2                   12    10202  12.so.0.1.2.2
- *    1.2.3rc1-6              12    10203  12.so.0.1.2.3rc1-6
- *    1.2.3                   12    10203  12.so.0.1.2.3
- *    1.2.4beta1-3            13    10204  12.so.0.1.2.4beta1-3
- *    1.0.14rc1               13    10014  10.so.0.1.0.14rc1
- *    1.2.4rc1                13    10204  12.so.0.1.2.4rc1
- *    1.0.14                  10    10014  10.so.0.1.0.14
- *    1.2.4                   13    10204  12.so.0.1.2.4
- *    1.2.5beta1-2            13    10205  12.so.0.1.2.5beta1-2
- *    1.0.15rc1-3             10    10015  10.so.0.1.0.15rc1-3
- *    1.2.5rc1-3              13    10205  12.so.0.1.2.5rc1-3
- *    1.0.15                  10    10015  10.so.0.1.0.15
- *    1.2.5                   13    10205  12.so.0.1.2.5
- *    1.2.6beta1-4            13    10206  12.so.0.1.2.6beta1-4
- *    1.0.16                  10    10016  10.so.0.1.0.16
- *    1.2.6                   13    10206  12.so.0.1.2.6
- *    1.2.7beta1-2            13    10207  12.so.0.1.2.7beta1-2
- *    1.0.17rc1               10    10017  12.so.0.1.0.17rc1
- *    1.2.7rc1                13    10207  12.so.0.1.2.7rc1
- *    1.0.17                  10    10017  12.so.0.1.0.17
- *    1.2.7                   13    10207  12.so.0.1.2.7
- *    1.2.8beta1-5            13    10208  12.so.0.1.2.8beta1-5
- *    1.0.18rc1-5             10    10018  12.so.0.1.0.18rc1-5
- *    1.2.8rc1-5              13    10208  12.so.0.1.2.8rc1-5
- *    1.0.18                  10    10018  12.so.0.1.0.18
- *    1.2.8                   13    10208  12.so.0.1.2.8
- *    1.2.9beta1-3            13    10209  12.so.0.1.2.9beta1-3
- *    1.2.9beta4-11           13    10209  12.so.0.9[.0]
- *    1.2.9rc1                13    10209  12.so.0.9[.0]
- *    1.2.9                   13    10209  12.so.0.9[.0]
- *    1.2.10beta1-7           13    10210  12.so.0.10[.0]
- *    1.2.10rc1-2             13    10210  12.so.0.10[.0]
- *    1.2.10                  13    10210  12.so.0.10[.0]
- *    1.4.0beta1-5            14    10400  14.so.0.0[.0]
- *    1.2.11beta1-4           13    10211  12.so.0.11[.0]
- *    1.4.0beta7-8            14    10400  14.so.0.0[.0]
- *    1.2.11                  13    10211  12.so.0.11[.0]
- *    1.2.12                  13    10212  12.so.0.12[.0]
- *    1.4.0beta9-14           14    10400  14.so.0.0[.0]
- *    1.2.13                  13    10213  12.so.0.13[.0]
- *    1.4.0beta15-36          14    10400  14.so.0.0[.0]
- *    1.4.0beta37-87          14    10400  14.so.14.0[.0]
- *    1.4.0rc01               14    10400  14.so.14.0[.0]
- *    1.4.0beta88-109         14    10400  14.so.14.0[.0]
- *    1.4.0rc02-08            14    10400  14.so.14.0[.0]
- *    1.4.0                   14    10400  14.so.14.0[.0]
- *    1.4.1beta01-03          14    10401  14.so.14.1[.0]
- *    1.4.1rc01               14    10401  14.so.14.1[.0]
- *    1.4.1beta04-12          14    10401  14.so.14.1[.0]
- *    1.4.1                   14    10401  14.so.14.1[.0]
- *    1.4.2                   14    10402  14.so.14.2[.0]
- *    1.4.3                   14    10403  14.so.14.3[.0]
- *    1.4.4                   14    10404  14.so.14.4[.0]
- *    1.5.0beta01-58          15    10500  15.so.15.0[.0]
- *    1.5.0rc01-07            15    10500  15.so.15.0[.0]
- *    1.5.0                   15    10500  15.so.15.0[.0]
- *    1.5.1beta01-11          15    10501  15.so.15.1[.0]
- *    1.5.1rc01-02            15    10501  15.so.15.1[.0]
- *    1.5.1                   15    10501  15.so.15.1[.0]
- *    1.5.2beta01-03          15    10502  15.so.15.2[.0]
- *    1.5.2rc01-03            15    10502  15.so.15.2[.0]
- *    1.5.2                   15    10502  15.so.15.2[.0]
- *    1.5.3beta01-10          15    10503  15.so.15.3[.0]
- *    1.5.3rc01-02            15    10503  15.so.15.3[.0]
- *    1.5.3beta11             15    10503  15.so.15.3[.0]
- *    1.5.3 [omitted]
- *    1.5.4beta01-08          15    10504  15.so.15.4[.0]
- *    1.5.4rc01               15    10504  15.so.15.4[.0]
- *    1.5.4                   15    10504  15.so.15.4[.0]
- *    1.5.5beta01-08          15    10505  15.so.15.5[.0]
- *    1.5.5rc01               15    10505  15.so.15.5[.0]
- *    1.5.5                   15    10505  15.so.15.5[.0]
- *    1.5.6beta01-07          15    10506  15.so.15.6[.0]
- *    1.5.6rc01-03            15    10506  15.so.15.6[.0]
- *    1.5.6                   15    10506  15.so.15.6[.0]
- *    1.5.7beta01-05          15    10507  15.so.15.7[.0]
- *    1.5.7rc01-03            15    10507  15.so.15.7[.0]
- *    1.5.7                   15    10507  15.so.15.7[.0]
- *    1.5.8beta01             15    10508  15.so.15.8[.0]
- *    1.5.8rc01               15    10508  15.so.15.8[.0]
- *    1.5.8                   15    10508  15.so.15.8[.0]
- *    1.5.9beta01-02          15    10509  15.so.15.9[.0]
- *    1.5.9rc01               15    10509  15.so.15.9[.0]
- *    1.5.9                   15    10509  15.so.15.9[.0]
- *    1.5.10beta01-05         15    10510  15.so.15.10[.0]
- *    1.5.10                  15    10510  15.so.15.10[.0]
- *
- *   Henceforth the source version will match the shared-library major
- *   and minor numbers; the shared-library major version number will be
- *   used for changes in backward compatibility, as it is intended.  The
- *   PNG_LIBPNG_VER macro, which is not used within libpng but is available
- *   for applications, is an unsigned integer of the form xyyzz corresponding
- *   to the source version x.y.z (leading zeros in y and z).  Beta versions
- *   were given the previous public release number plus a letter, until
- *   version 1.0.6j; from then on they were given the upcoming public
- *   release number plus "betaNN" or "rcNN".
- *
- *   Binary incompatibility exists only when applications make direct access
- *   to the info_ptr or png_ptr members through png.h, and the compiled
- *   application is loaded with a different version of the library.
- *
- *   DLLNUM will change each time there are forward or backward changes
- *   in binary compatibility (e.g., when a new feature is added).
- *
- * See libpng-manual.txt or libpng.3 for more information.  The PNG
- * specification is available as a W3C Recommendation and as an ISO
- * Specification, <http://www.w3.org/TR/2003/REC-PNG-20031110/
- */
-
-/*
- * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
- *
- * If you modify libpng you may insert additional notices immediately following
- * this sentence.
- *
- * This code is released under the libpng license.
- *
- * libpng versions 1.2.6, August 15, 2004, through 1.5.10, March 29, 2012, are
- * Copyright (c) 2004, 2006-2012 Glenn Randers-Pehrson, and are
- * distributed according to the same disclaimer and license as libpng-1.2.5
- * with the following individual added to the list of Contributing Authors:
- *
- *    Cosmin Truta
- *
- * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
- * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
- * distributed according to the same disclaimer and license as libpng-1.0.6
- * with the following individuals added to the list of Contributing Authors:
- *
- *    Simon-Pierre Cadieux
- *    Eric S. Raymond
- *    Gilles Vollant
- *
- * and with the following additions to the disclaimer:
- *
- *    There is no warranty against interference with your enjoyment of the
- *    library or against infringement.  There is no warranty that our
- *    efforts or the library will fulfill any of your particular purposes
- *    or needs.  This library is provided with all faults, and the entire
- *    risk of satisfactory quality, performance, accuracy, and effort is with
- *    the user.
- *
- * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
- * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
- * distributed according to the same disclaimer and license as libpng-0.96,
- * with the following individuals added to the list of Contributing Authors:
- *
- *    Tom Lane
- *    Glenn Randers-Pehrson
- *    Willem van Schaik
- *
- * libpng versions 0.89, June 1996, through 0.96, May 1997, are
- * Copyright (c) 1996, 1997 Andreas Dilger
- * Distributed according to the same disclaimer and license as libpng-0.88,
- * with the following individuals added to the list of Contributing Authors:
- *
- *    John Bowler
- *    Kevin Bracey
- *    Sam Bushell
- *    Magnus Holmgren
- *    Greg Roelofs
- *    Tom Tanner
- *
- * libpng versions 0.5, May 1995, through 0.88, January 1996, are
- * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
- *
- * For the purposes of this copyright and license, "Contributing Authors"
- * is defined as the following set of individuals:
- *
- *    Andreas Dilger
- *    Dave Martindale
- *    Guy Eric Schalnat
- *    Paul Schmidt
- *    Tim Wegner
- *
- * The PNG Reference Library is supplied "AS IS".  The Contributing Authors
- * and Group 42, Inc. disclaim all warranties, expressed or implied,
- * including, without limitation, the warranties of merchantability and of
- * fitness for any purpose.  The Contributing Authors and Group 42, Inc.
- * assume no liability for direct, indirect, incidental, special, exemplary,
- * or consequential damages, which may result from the use of the PNG
- * Reference Library, even if advised of the possibility of such damage.
- *
- * Permission is hereby granted to use, copy, modify, and distribute this
- * source code, or portions hereof, for any purpose, without fee, subject
- * to the following restrictions:
- *
- *   1. The origin of this source code must not be misrepresented.
- *
- *   2. Altered versions must be plainly marked as such and must not
- *      be misrepresented as being the original source.
- *
- *   3. This Copyright notice may not be removed or altered from
- *      any source or altered source distribution.
- *
- * The Contributing Authors and Group 42, Inc. specifically permit, without
- * fee, and encourage the use of this source code as a component to
- * supporting the PNG file format in commercial products.  If you use this
- * source code in a product, acknowledgment is not required but would be
- * appreciated.
- */
-
-/*
- * A "png_get_copyright" function is available, for convenient use in "about"
- * boxes and the like:
- *
- *     printf("%s", png_get_copyright(NULL));
- *
- * Also, the PNG logo (in PNG format, of course) is supplied in the
- * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
- */
-
-/*
- * Libpng is OSI Certified Open Source Software.  OSI Certified is a
- * certification mark of the Open Source Initiative.
- */
-
-/*
- * The contributing authors would like to thank all those who helped
- * with testing, bug fixes, and patience.  This wouldn't have been
- * possible without all of you.
- *
- * Thanks to Frank J. T. Wojcik for helping with the documentation.
- */
-
-/*
- * Y2K compliance in libpng:
- * =========================
- *
- *    March 29, 2012
- *
- *    Since the PNG Development group is an ad-hoc body, we can't make
- *    an official declaration.
- *
- *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.5.10 are Y2K compliant.  It is my belief that
- *    earlier versions were also Y2K compliant.
- *
- *    Libpng only has two year fields.  One is a 2-byte unsigned integer
- *    that will hold years up to 65535.  The other holds the date in text
- *    format, and will hold years up to 9999.
- *
- *    The integer is
- *        "png_uint_16 year" in png_time_struct.
- *
- *    The string is
- *        "png_char time_buffer" in png_struct
- *
- *    There are seven time-related functions:
- *        png.c: png_convert_to_rfc_1123() in png.c
- *          (formerly png_convert_to_rfc_1152() in error)
- *        png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
- *        png_convert_from_time_t() in pngwrite.c
- *        png_get_tIME() in pngget.c
- *        png_handle_tIME() in pngrutil.c, called in pngread.c
- *        png_set_tIME() in pngset.c
- *        png_write_tIME() in pngwutil.c, called in pngwrite.c
- *
- *    All handle dates properly in a Y2K environment.  The
- *    png_convert_from_time_t() function calls gmtime() to convert from system
- *    clock time, which returns (year - 1900), which we properly convert to
- *    the full 4-digit year.  There is a possibility that applications using
- *    libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
- *    function, or that they are incorrectly passing only a 2-digit year
- *    instead of "year - 1900" into the png_convert_from_struct_tm() function,
- *    but this is not under our control.  The libpng documentation has always
- *    stated that it works with 4-digit years, and the APIs have been
- *    documented as such.
- *
- *    The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
- *    integer to hold the year, and can hold years as large as 65535.
- *
- *    zlib, upon which libpng depends, is also Y2K compliant.  It contains
- *    no date-related code.
- *
- *       Glenn Randers-Pehrson
- *       libpng maintainer
- *       PNG Development Group
- */
-
-#ifndef PNG_H
-#define PNG_H
-
-/* This is not the place to learn how to use libpng. The file libpng-manual.txt
- * describes how to use libpng, and the file example.c summarizes it
- * with some code on which to build.  This file is useful for looking
- * at the actual function definitions and structure components.
- *
- * If you just need to read a PNG file and don't want to read the documentation
- * skip to the end of this file and read the section entitled 'simplified API'.
- */
-
-/* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.5.10"
-#define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.5.10 - March 29, 2012\n"
-
-#define PNG_LIBPNG_VER_SONUM   15
-#define PNG_LIBPNG_VER_DLLNUM  15
-
-/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
-#define PNG_LIBPNG_VER_MAJOR   1
-#define PNG_LIBPNG_VER_MINOR   5
-#define PNG_LIBPNG_VER_RELEASE 10
-
-/* This should match the numeric part of the final component of
- * PNG_LIBPNG_VER_STRING, omitting any leading zero:
- */
-
-#define PNG_LIBPNG_VER_BUILD  0
-
-/* Release Status */
-#define PNG_LIBPNG_BUILD_ALPHA    1
-#define PNG_LIBPNG_BUILD_BETA     2
-#define PNG_LIBPNG_BUILD_RC       3
-#define PNG_LIBPNG_BUILD_STABLE   4
-#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
-
-/* Release-Specific Flags */
-#define PNG_LIBPNG_BUILD_PATCH    8 /* Can be OR'ed with
-                                       PNG_LIBPNG_BUILD_STABLE only */
-#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
-                                       PNG_LIBPNG_BUILD_SPECIAL */
-#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
-                                       PNG_LIBPNG_BUILD_PRIVATE */
-
-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
-
-/* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
- * We must not include leading zeros.
- * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
- * version 1.0.0 was mis-numbered 100 instead of 10000).  From
- * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
- */
-#define PNG_LIBPNG_VER 10510 /* 1.5.10 */
-
-/* Library configuration: these options cannot be changed after
- * the library has been built.
- */
-#ifndef PNGLCONF_H
-    /* If pnglibconf.h is missing, you can
-     * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
-     */
-#   include "pnglibconf.h"
-#endif
-
-#ifndef PNG_VERSION_INFO_ONLY
-#  ifndef PNG_BUILDING_SYMBOL_TABLE
-  /*
-   *   Standard header files (not needed for the version info or while
-   *   building symbol table -- see scripts/pnglibconf.dfa)
-   */
-#    ifdef PNG_SETJMP_SUPPORTED
-#      include <setjmp.h>
-#    endif
-
-    /* Need the time information for converting tIME chunks, it
-     * defines struct tm:
-     */
-#    ifdef PNG_CONVERT_tIME_SUPPORTED
-       /* "time.h" functions are not supported on all operating systems */
-#      include <time.h>
-#    endif
-#  endif
-
-/* Machine specific configuration. */
-#  include "pngconf.h"
-#endif
-
-/*
- * Added at libpng-1.2.8
- *
- * Ref MSDN: Private as priority over Special
- * VS_FF_PRIVATEBUILD File *was not* built using standard release
- * procedures. If this value is given, the StringFileInfo block must
- * contain a PrivateBuild string.
- *
- * VS_FF_SPECIALBUILD File *was* built by the original company using
- * standard release procedures but is a variation of the standard
- * file of the same version number. If this value is given, the
- * StringFileInfo block must contain a SpecialBuild string.
- */
-
-#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
-#  define PNG_LIBPNG_BUILD_TYPE \
-       (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
-#else
-#  ifdef PNG_LIBPNG_SPECIALBUILD
-#    define PNG_LIBPNG_BUILD_TYPE \
-         (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
-#  else
-#    define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
-#  endif
-#endif
-
-#ifndef PNG_VERSION_INFO_ONLY
-
-/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-
-/* Version information for C files, stored in png.c.  This had better match
- * the version above.
- */
-#define png_libpng_ver png_get_header_ver(NULL)
-
-/* This file is arranged in several sections:
- *
- * 1. Any configuration options that can be specified by for the application
- *    code when it is built.  (Build time configuration is in pnglibconf.h)
- * 2. Type definitions (base types are defined in pngconf.h), structure
- *    definitions.
- * 3. Exported library functions.
- *
- * The library source code has additional files (principally pngpriv.h) that
- * allow configuration of the library.
- */
-/* Section 1: run time configuration
- * See pnglibconf.h for build time configuration
- *
- * Run time configuration allows the application to choose between
- * implementations of certain arithmetic APIs.  The default is set
- * at build time and recorded in pnglibconf.h, but it is safe to
- * override these (and only these) settings.  Note that this won't
- * change what the library does, only application code, and the
- * settings can (and probably should) be made on a per-file basis
- * by setting the #defines before including png.h
- *
- * Use macros to read integers from PNG data or use the exported
- * functions?
- *   PNG_USE_READ_MACROS: use the macros (see below)  Note that
- *     the macros evaluate their argument multiple times.
- *   PNG_NO_USE_READ_MACROS: call the relevant library function.
- *
- * Use the alternative algorithm for compositing alpha samples that
- * does not use division?
- *   PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
- *      algorithm.
- *   PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
- *
- * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
- * false?
- *   PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
- *      APIs to png_warning.
- * Otherwise the calls are mapped to png_error.
- */
-
-/* Section 2: type definitions, including structures and compile time
- * constants.
- * See pngconf.h for base types that vary by machine/system
- */
-
-/* This triggers a compiler error in png.c, if png.c and png.h
- * do not agree upon the version number.
- */
-typedef char* png_libpng_version_1_5_10;
-
-/* Three color definitions.  The order of the red, green, and blue, (and the
- * exact size) is not important, although the size of the fields need to
- * be png_byte or png_uint_16 (as defined below).
- */
-typedef struct png_color_struct
-{
-   png_byte red;
-   png_byte green;
-   png_byte blue;
-} png_color;
-typedef png_color FAR * png_colorp;
-typedef PNG_CONST png_color FAR * png_const_colorp;
-typedef png_color FAR * FAR * png_colorpp;
-
-typedef struct png_color_16_struct
-{
-   png_byte index;    /* used for palette files */
-   png_uint_16 red;   /* for use in red green blue files */
-   png_uint_16 green;
-   png_uint_16 blue;
-   png_uint_16 gray;  /* for use in grayscale files */
-} png_color_16;
-typedef png_color_16 FAR * png_color_16p;
-typedef PNG_CONST png_color_16 FAR * png_const_color_16p;
-typedef png_color_16 FAR * FAR * png_color_16pp;
-
-typedef struct png_color_8_struct
-{
-   png_byte red;   /* for use in red green blue files */
-   png_byte green;
-   png_byte blue;
-   png_byte gray;  /* for use in grayscale files */
-   png_byte alpha; /* for alpha channel files */
-} png_color_8;
-typedef png_color_8 FAR * png_color_8p;
-typedef PNG_CONST png_color_8 FAR * png_const_color_8p;
-typedef png_color_8 FAR * FAR * png_color_8pp;
-
-/*
- * The following two structures are used for the in-core representation
- * of sPLT chunks.
- */
-typedef struct png_sPLT_entry_struct
-{
-   png_uint_16 red;
-   png_uint_16 green;
-   png_uint_16 blue;
-   png_uint_16 alpha;
-   png_uint_16 frequency;
-} png_sPLT_entry;
-typedef png_sPLT_entry FAR * png_sPLT_entryp;
-typedef PNG_CONST png_sPLT_entry FAR * png_const_sPLT_entryp;
-typedef png_sPLT_entry FAR * FAR * png_sPLT_entrypp;
-
-/*  When the depth of the sPLT palette is 8 bits, the color and alpha samples
- *  occupy the LSB of their respective members, and the MSB of each member
- *  is zero-filled.  The frequency member always occupies the full 16 bits.
- */
-
-typedef struct png_sPLT_struct
-{
-   png_charp name;           /* palette name */
-   png_byte depth;           /* depth of palette samples */
-   png_sPLT_entryp entries;  /* palette entries */
-   png_int_32 nentries;      /* number of palette entries */
-} png_sPLT_t;
-typedef png_sPLT_t FAR * png_sPLT_tp;
-typedef PNG_CONST png_sPLT_t FAR * png_const_sPLT_tp;
-typedef png_sPLT_t FAR * FAR * png_sPLT_tpp;
-
-#ifdef PNG_TEXT_SUPPORTED
-/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
- * and whether that contents is compressed or not.  The "key" field
- * points to a regular zero-terminated C string.  The "text" fields can be a
- * regular C string, an empty string, or a NULL pointer.
- * However, the structure returned by png_get_text() will always contain
- * the "text" field as a regular zero-terminated C string (possibly
- * empty), never a NULL pointer, so it can be safely used in printf() and
- * other string-handling functions.  Note that the "itxt_length", "lang", and
- * "lang_key" members of the structure only exist when the library is built
- * with iTXt chunk support.  Prior to libpng-1.4.0 the library was built by
- * default without iTXt support. Also note that when iTXt *is* supported,
- * the "lang" and "lang_key" fields contain NULL pointers when the
- * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
- * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
- * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
- * which is always 0 or 1, or its "compression method" which is always 0.
- */
-typedef struct png_text_struct
-{
-   int  compression;       /* compression value:
-                             -1: tEXt, none
-                              0: zTXt, deflate
-                              1: iTXt, none
-                              2: iTXt, deflate  */
-   png_charp key;          /* keyword, 1-79 character description of "text" */
-   png_charp text;         /* comment, may be an empty string (ie "")
-                              or a NULL pointer */
-   png_size_t text_length; /* length of the text string */
-   png_size_t itxt_length; /* length of the itxt string */
-   png_charp lang;         /* language code, 0-79 characters
-                              or a NULL pointer */
-   png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
-                              chars or a NULL pointer */
-} png_text;
-typedef png_text FAR * png_textp;
-typedef PNG_CONST png_text FAR * png_const_textp;
-typedef png_text FAR * FAR * png_textpp;
-#endif
-
-/* Supported compression types for text in PNG files (tEXt, and zTXt).
- * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
-#define PNG_TEXT_COMPRESSION_NONE_WR -3
-#define PNG_TEXT_COMPRESSION_zTXt_WR -2
-#define PNG_TEXT_COMPRESSION_NONE    -1
-#define PNG_TEXT_COMPRESSION_zTXt     0
-#define PNG_ITXT_COMPRESSION_NONE     1
-#define PNG_ITXT_COMPRESSION_zTXt     2
-#define PNG_TEXT_COMPRESSION_LAST     3  /* Not a valid value */
-
-/* png_time is a way to hold the time in an machine independent way.
- * Two conversions are provided, both from time_t and struct tm.  There
- * is no portable way to convert to either of these structures, as far
- * as I know.  If you know of a portable way, send it to me.  As a side
- * note - PNG has always been Year 2000 compliant!
- */
-typedef struct png_time_struct
-{
-   png_uint_16 year; /* full year, as in, 1995 */
-   png_byte month;   /* month of year, 1 - 12 */
-   png_byte day;     /* day of month, 1 - 31 */
-   png_byte hour;    /* hour of day, 0 - 23 */
-   png_byte minute;  /* minute of hour, 0 - 59 */
-   png_byte second;  /* second of minute, 0 - 60 (for leap seconds) */
-} png_time;
-typedef png_time FAR * png_timep;
-typedef PNG_CONST png_time FAR * png_const_timep;
-typedef png_time FAR * FAR * png_timepp;
-
-#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) || \
-    defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
-/* png_unknown_chunk is a structure to hold queued chunks for which there is
- * no specific support.  The idea is that we can use this to queue
- * up private chunks for output even though the library doesn't actually
- * know about their semantics.
- */
-typedef struct png_unknown_chunk_t
-{
-    png_byte name[5];
-    png_byte *data;
-    png_size_t size;
-
-    /* libpng-using applications should NOT directly modify this byte. */
-    png_byte location; /* mode of operation at read time */
-}
-
-
-png_unknown_chunk;
-typedef png_unknown_chunk FAR * png_unknown_chunkp;
-typedef PNG_CONST png_unknown_chunk FAR * png_const_unknown_chunkp;
-typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
-#endif
-
-/* Values for the unknown chunk location byte */
-
-#define PNG_HAVE_IHDR  0x01
-#define PNG_HAVE_PLTE  0x02
-#define PNG_AFTER_IDAT 0x08
-
-/* The complete definition of png_info has, as of libpng-1.5.0,
- * been moved into a separate header file that is not accessible to
- * applications.  Read libpng-manual.txt or libpng.3 for more info.
- */
-typedef struct png_info_def png_info;
-typedef png_info FAR * png_infop;
-typedef PNG_CONST png_info FAR * png_const_infop;
-typedef png_info FAR * FAR * png_infopp;
-
-/* Maximum positive integer used in PNG is (2^31)-1 */
-#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
-#define PNG_UINT_32_MAX ((png_uint_32)(-1))
-#define PNG_SIZE_MAX ((png_size_t)(-1))
-
-/* These are constants for fixed point values encoded in the
- * PNG specification manner (x100000)
- */
-#define PNG_FP_1    100000
-#define PNG_FP_HALF  50000
-#define PNG_FP_MAX  ((png_fixed_point)0x7fffffffL)
-#define PNG_FP_MIN  (-PNG_FP_MAX)
-
-/* These describe the color_type field in png_info. */
-/* color type masks */
-#define PNG_COLOR_MASK_PALETTE    1
-#define PNG_COLOR_MASK_COLOR      2
-#define PNG_COLOR_MASK_ALPHA      4
-
-/* color types.  Note that not all combinations are legal */
-#define PNG_COLOR_TYPE_GRAY 0
-#define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
-#define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
-#define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
-#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
-/* aliases */
-#define PNG_COLOR_TYPE_RGBA  PNG_COLOR_TYPE_RGB_ALPHA
-#define PNG_COLOR_TYPE_GA  PNG_COLOR_TYPE_GRAY_ALPHA
-
-/* This is for compression type. PNG 1.0-1.2 only define the single type. */
-#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
-#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
-
-/* This is for filter type. PNG 1.0-1.2 only define the single type. */
-#define PNG_FILTER_TYPE_BASE      0 /* Single row per-byte filtering */
-#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
-#define PNG_FILTER_TYPE_DEFAULT   PNG_FILTER_TYPE_BASE
-
-/* These are for the interlacing type.  These values should NOT be changed. */
-#define PNG_INTERLACE_NONE        0 /* Non-interlaced image */
-#define PNG_INTERLACE_ADAM7       1 /* Adam7 interlacing */
-#define PNG_INTERLACE_LAST        2 /* Not a valid value */
-
-/* These are for the oFFs chunk.  These values should NOT be changed. */
-#define PNG_OFFSET_PIXEL          0 /* Offset in pixels */
-#define PNG_OFFSET_MICROMETER     1 /* Offset in micrometers (1/10^6 meter) */
-#define PNG_OFFSET_LAST           2 /* Not a valid value */
-
-/* These are for the pCAL chunk.  These values should NOT be changed. */
-#define PNG_EQUATION_LINEAR       0 /* Linear transformation */
-#define PNG_EQUATION_BASE_E       1 /* Exponential base e transform */
-#define PNG_EQUATION_ARBITRARY    2 /* Arbitrary base exponential transform */
-#define PNG_EQUATION_HYPERBOLIC   3 /* Hyperbolic sine transformation */
-#define PNG_EQUATION_LAST         4 /* Not a valid value */
-
-/* These are for the sCAL chunk.  These values should NOT be changed. */
-#define PNG_SCALE_UNKNOWN         0 /* unknown unit (image scale) */
-#define PNG_SCALE_METER           1 /* meters per pixel */
-#define PNG_SCALE_RADIAN          2 /* radians per pixel */
-#define PNG_SCALE_LAST            3 /* Not a valid value */
-
-/* These are for the pHYs chunk.  These values should NOT be changed. */
-#define PNG_RESOLUTION_UNKNOWN    0 /* pixels/unknown unit (aspect ratio) */
-#define PNG_RESOLUTION_METER      1 /* pixels/meter */
-#define PNG_RESOLUTION_LAST       2 /* Not a valid value */
-
-/* These are for the sRGB chunk.  These values should NOT be changed. */
-#define PNG_sRGB_INTENT_PERCEPTUAL 0
-#define PNG_sRGB_INTENT_RELATIVE   1
-#define PNG_sRGB_INTENT_SATURATION 2
-#define PNG_sRGB_INTENT_ABSOLUTE   3
-#define PNG_sRGB_INTENT_LAST       4 /* Not a valid value */
-
-/* This is for text chunks */
-#define PNG_KEYWORD_MAX_LENGTH     79
-
-/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
-#define PNG_MAX_PALETTE_LENGTH    256
-
-/* These determine if an ancillary chunk's data has been successfully read
- * from the PNG header, or if the application has filled in the corresponding
- * data in the info_struct to be written into the output file.  The values
- * of the PNG_INFO_<chunk> defines should NOT be changed.
- */
-#define PNG_INFO_gAMA 0x0001
-#define PNG_INFO_sBIT 0x0002
-#define PNG_INFO_cHRM 0x0004
-#define PNG_INFO_PLTE 0x0008
-#define PNG_INFO_tRNS 0x0010
-#define PNG_INFO_bKGD 0x0020
-#define PNG_INFO_hIST 0x0040
-#define PNG_INFO_pHYs 0x0080
-#define PNG_INFO_oFFs 0x0100
-#define PNG_INFO_tIME 0x0200
-#define PNG_INFO_pCAL 0x0400
-#define PNG_INFO_sRGB 0x0800   /* GR-P, 0.96a */
-#define PNG_INFO_iCCP 0x1000   /* ESR, 1.0.6 */
-#define PNG_INFO_sPLT 0x2000   /* ESR, 1.0.6 */
-#define PNG_INFO_sCAL 0x4000   /* ESR, 1.0.6 */
-#define PNG_INFO_IDAT 0x8000   /* ESR, 1.0.6 */
-
-/* This is used for the transformation routines, as some of them
- * change these values for the row.  It also should enable using
- * the routines for other purposes.
- */
-typedef struct png_row_info_struct
-{
-   png_uint_32 width;    /* width of row */
-   png_size_t rowbytes;  /* number of bytes in row */
-   png_byte color_type;  /* color type of row */
-   png_byte bit_depth;   /* bit depth of row */
-   png_byte channels;    /* number of channels (1, 2, 3, or 4) */
-   png_byte pixel_depth; /* bits per pixel (depth * channels) */
-} png_row_info;
-
-typedef png_row_info FAR * png_row_infop;
-typedef png_row_info FAR * FAR * png_row_infopp;
-
-/* The complete definition of png_struct has, as of libpng-1.5.0,
- * been moved into a separate header file that is not accessible to
- * applications.  Read libpng-manual.txt or libpng.3 for more info.
- */
-typedef struct png_struct_def png_struct;
-typedef PNG_CONST png_struct FAR * png_const_structp;
-typedef png_struct FAR * png_structp;
-
-/* These are the function types for the I/O functions and for the functions
- * that allow the user to override the default I/O functions with his or her
- * own.  The png_error_ptr type should match that of user-supplied warning
- * and error functions, while the png_rw_ptr type should match that of the
- * user read/write data functions.  Note that the 'write' function must not
- * modify the buffer it is passed. The 'read' function, on the other hand, is
- * expected to return the read data in the buffer.
- */
-typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
-typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
-typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
-typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
-    int));
-typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
-    int));
-
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
-typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
-
-/* The following callback receives png_uint_32 row_number, int pass for the
- * png_bytep data of the row.  When transforming an interlaced image the
- * row number is the row number within the sub-image of the interlace pass, so
- * the value will increase to the height of the sub-image (not the full image)
- * then reset to 0 for the next pass.
- *
- * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
- * find the output pixel (x,y) given an interlaced sub-image pixel
- * (row,col,pass).  (See below for these macros.)
- */
-typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
-    png_uint_32, int));
-#endif
-
-#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
-    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
-typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
-    png_bytep));
-#endif
-
-#ifdef PNG_USER_CHUNKS_SUPPORTED
-typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
-    png_unknown_chunkp));
-#endif
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp));
-#endif
-
-#ifdef PNG_SETJMP_SUPPORTED
-/* This must match the function definition in <setjmp.h>, and the application
- * must include this before png.h to obtain the definition of jmp_buf.  The
- * function is required to be PNG_NORETURN, but this is not checked.  If the
- * function does return the application will crash via an abort() or similar
- * system level call.
- *
- * If you get a warning here while building the library you may need to make
- * changes to ensure that pnglibconf.h records the calling convention used by
- * your compiler.  This may be very difficult - try using a different compiler
- * to build the library!
- */
-PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
-#endif
-
-/* Transform masks for the high-level interface */
-#define PNG_TRANSFORM_IDENTITY       0x0000    /* read and write */
-#define PNG_TRANSFORM_STRIP_16       0x0001    /* read only */
-#define PNG_TRANSFORM_STRIP_ALPHA    0x0002    /* read only */
-#define PNG_TRANSFORM_PACKING        0x0004    /* read and write */
-#define PNG_TRANSFORM_PACKSWAP       0x0008    /* read and write */
-#define PNG_TRANSFORM_EXPAND         0x0010    /* read only */
-#define PNG_TRANSFORM_INVERT_MONO    0x0020    /* read and write */
-#define PNG_TRANSFORM_SHIFT          0x0040    /* read and write */
-#define PNG_TRANSFORM_BGR            0x0080    /* read and write */
-#define PNG_TRANSFORM_SWAP_ALPHA     0x0100    /* read and write */
-#define PNG_TRANSFORM_SWAP_ENDIAN    0x0200    /* read and write */
-#define PNG_TRANSFORM_INVERT_ALPHA   0x0400    /* read and write */
-#define PNG_TRANSFORM_STRIP_FILLER   0x0800    /* write only */
-/* Added to libpng-1.2.34 */
-#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
-#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
-/* Added to libpng-1.4.0 */
-#define PNG_TRANSFORM_GRAY_TO_RGB   0x2000      /* read only */
-/* Added to libpng-1.5.4 */
-#define PNG_TRANSFORM_EXPAND_16     0x4000      /* read only */
-#define PNG_TRANSFORM_SCALE_16      0x8000      /* read only */
-
-/* Flags for MNG supported features */
-#define PNG_FLAG_MNG_EMPTY_PLTE     0x01
-#define PNG_FLAG_MNG_FILTER_64      0x04
-#define PNG_ALL_MNG_FEATURES        0x05
-
-/* NOTE: prior to 1.5 these functions had no 'API' style declaration,
- * this allowed the zlib default functions to be used on Windows
- * platforms.  In 1.5 the zlib default malloc (which just calls malloc and
- * ignores the first argument) should be completely compatible with the
- * following.
- */
-typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
-    png_alloc_size_t));
-typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
-
-typedef png_struct FAR * FAR * png_structpp;
-
-/* Section 3: exported functions
- * Here are the function definitions most commonly used.  This is not
- * the place to find out how to use libpng.  See libpng-manual.txt for the
- * full explanation, see example.c for the summary.  This just provides
- * a simple one line description of the use of each function.
- *
- * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
- * pngconf.h and in the *.dfn files in the scripts directory.
- *
- *   PNG_EXPORT(ordinal, type, name, (args));
- *
- *       ordinal:    ordinal that is used while building
- *                   *.def files. The ordinal value is only
- *                   relevant when preprocessing png.h with
- *                   the *.dfn files for building symbol table
- *                   entries, and are removed by pngconf.h.
- *       type:       return type of the function
- *       name:       function name
- *       args:       function arguments, with types
- *
- * When we wish to append attributes to a function prototype we use
- * the PNG_EXPORTA() macro instead.
- *
- *   PNG_EXPORTA(ordinal, type, name, (args), attributes);
- *
- *       ordinal, type, name, and args: same as in PNG_EXPORT().
- *       attributes: function attributes
- */
-
-/* Returns the version number of the library */
-PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
-
-/* Tell lib we have already handled the first <num_bytes> magic bytes.
- * Handling more than 8 bytes from the beginning of the file is an error.
- */
-PNG_EXPORT(2, void, png_set_sig_bytes, (png_structp png_ptr, int num_bytes));
-
-/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
- * PNG file.  Returns zero if the supplied bytes match the 8-byte PNG
- * signature, and non-zero otherwise.  Having num_to_check == 0 or
- * start > 7 will always fail (ie return non-zero).
- */
-PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
-    png_size_t num_to_check));
-
-/* Simple signature checking function.  This is the same as calling
- * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
- */
-#define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
-
-/* Allocate and initialize png_ptr struct for reading, and any other memory. */
-PNG_EXPORTA(4, png_structp, png_create_read_struct,
-    (png_const_charp user_png_ver, png_voidp error_ptr,
-    png_error_ptr error_fn, png_error_ptr warn_fn),
-    PNG_ALLOCATED);
-
-/* Allocate and initialize png_ptr struct for writing, and any other memory */
-PNG_EXPORTA(5, png_structp, png_create_write_struct,
-    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
-    png_error_ptr warn_fn),
-    PNG_ALLOCATED);
-
-PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
-    (png_const_structp png_ptr));
-
-PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structp png_ptr,
-    png_size_t size));
-
-/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
- * match up.
- */
-#ifdef PNG_SETJMP_SUPPORTED
-/* This function returns the jmp_buf built in to *png_ptr.  It must be
- * supplied with an appropriate 'longjmp' function to use on that jmp_buf
- * unless the default error function is overridden in which case NULL is
- * acceptable.  The size of the jmp_buf is checked against the actual size
- * allocated by the library - the call will return NULL on a mismatch
- * indicating an ABI mismatch.
- */
-PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structp png_ptr,
-    png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
-#  define png_jmpbuf(png_ptr) \
-      (*png_set_longjmp_fn((png_ptr), longjmp, sizeof (jmp_buf)))
-#else
-#  define png_jmpbuf(png_ptr) \
-      (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
-#endif
-/* This function should be used by libpng applications in place of
- * longjmp(png_ptr->jmpbuf, val).  If longjmp_fn() has been set, it
- * will use it; otherwise it will call PNG_ABORT().  This function was
- * added in libpng-1.5.0.
- */
-PNG_EXPORTA(9, void, png_longjmp, (png_structp png_ptr, int val),
-    PNG_NORETURN);
-
-#ifdef PNG_READ_SUPPORTED
-/* Reset the compression stream */
-PNG_EXPORT(10, int, png_reset_zstream, (png_structp png_ptr));
-#endif
-
-/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
-#ifdef PNG_USER_MEM_SUPPORTED
-PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
-    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
-    png_error_ptr warn_fn,
-    png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
-    PNG_ALLOCATED);
-PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
-    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
-    png_error_ptr warn_fn,
-    png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
-    PNG_ALLOCATED);
-#endif
-
-/* Write the PNG file signature. */
-PNG_EXPORT(13, void, png_write_sig, (png_structp png_ptr));
-
-/* Write a PNG chunk - size, type, (optional) data, CRC. */
-PNG_EXPORT(14, void, png_write_chunk, (png_structp png_ptr, png_const_bytep
-    chunk_name, png_const_bytep data, png_size_t length));
-
-/* Write the start of a PNG chunk - length and chunk name. */
-PNG_EXPORT(15, void, png_write_chunk_start, (png_structp png_ptr,
-    png_const_bytep chunk_name, png_uint_32 length));
-
-/* Write the data of a PNG chunk started with png_write_chunk_start(). */
-PNG_EXPORT(16, void, png_write_chunk_data, (png_structp png_ptr,
-    png_const_bytep data, png_size_t length));
-
-/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
-PNG_EXPORT(17, void, png_write_chunk_end, (png_structp png_ptr));
-
-/* Allocate and initialize the info structure */
-PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_structp png_ptr),
-    PNG_ALLOCATED);
-
-PNG_EXPORT(19, void, png_info_init_3, (png_infopp info_ptr,
-    png_size_t png_info_struct_size));
-
-/* Writes all the PNG information before the image. */
-PNG_EXPORT(20, void, png_write_info_before_PLTE,
-    (png_structp png_ptr, png_infop info_ptr));
-PNG_EXPORT(21, void, png_write_info,
-    (png_structp png_ptr, png_infop info_ptr));
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Read the information before the actual image data. */
-PNG_EXPORT(22, void, png_read_info,
-    (png_structp png_ptr, png_infop info_ptr));
-#endif
-
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-PNG_EXPORT(23, png_const_charp, png_convert_to_rfc1123,
-    (png_structp png_ptr,
-    png_const_timep ptime));
-#endif
-
-#ifdef PNG_CONVERT_tIME_SUPPORTED
-/* Convert from a struct tm to png_time */
-PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
-    PNG_CONST struct tm FAR * ttime));
-
-/* Convert from time_t to png_time.  Uses gmtime() */
-PNG_EXPORT(25, void, png_convert_from_time_t,
-    (png_timep ptime, time_t ttime));
-#endif /* PNG_CONVERT_tIME_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
-PNG_EXPORT(26, void, png_set_expand, (png_structp png_ptr));
-PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structp png_ptr));
-PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structp png_ptr));
-PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
- * of a tRNS chunk if present.
- */
-PNG_EXPORT(221, void, png_set_expand_16, (png_structp png_ptr));
-#endif
-
-#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
-/* Use blue, green, red order for pixels. */
-PNG_EXPORT(30, void, png_set_bgr, (png_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-/* Expand the grayscale to 24-bit RGB if necessary. */
-PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-/* Reduce RGB to grayscale. */
-#define PNG_ERROR_ACTION_NONE  1
-#define PNG_ERROR_ACTION_WARN  2
-#define PNG_ERROR_ACTION_ERROR 3
-#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
-
-PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structp png_ptr,
-    int error_action, double red, double green));
-PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structp png_ptr,
-    int error_action, png_fixed_point red, png_fixed_point green));
-
-PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structp
-    png_ptr));
-#endif
-
-#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
-PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
-    png_colorp palette));
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-/* How the alpha channel is interpreted - this affects how the color channels of
- * a PNG file are returned when an alpha channel, or tRNS chunk in a palette
- * file, is present.
- *
- * This has no effect on the way pixels are written into a PNG output
- * datastream. The color samples in a PNG datastream are never premultiplied
- * with the alpha samples.
- *
- * The default is to return data according to the PNG specification: the alpha
- * channel is a linear measure of the contribution of the pixel to the
- * corresponding composited pixel.  The gamma encoded color channels must be
- * scaled according to the contribution and to do this it is necessary to undo
- * the encoding, scale the color values, perform the composition and reencode
- * the values.  This is the 'PNG' mode.
- *
- * The alternative is to 'associate' the alpha with the color information by
- * storing color channel values that have been scaled by the alpha.  The
- * advantage is that the color channels can be resampled (the image can be
- * scaled) in this form.  The disadvantage is that normal practice is to store
- * linear, not (gamma) encoded, values and this requires 16-bit channels for
- * still images rather than the 8-bit channels that are just about sufficient if
- * gamma encoding is used.  In addition all non-transparent pixel values,
- * including completely opaque ones, must be gamma encoded to produce the final
- * image.  This is the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' mode (the
- * latter being the two common names for associated alpha color channels.)
- *
- * Since it is not necessary to perform arithmetic on opaque color values so
- * long as they are not to be resampled and are in the final color space it is
- * possible to optimize the handling of alpha by storing the opaque pixels in
- * the PNG format (adjusted for the output color space) while storing partially
- * opaque pixels in the standard, linear, format.  The accuracy required for
- * standard alpha composition is relatively low, because the pixels are
- * isolated, therefore typically the accuracy loss in storing 8-bit linear
- * values is acceptable.  (This is not true if the alpha channel is used to
- * simulate transparency over large areas - use 16 bits or the PNG mode in
- * this case!)  This is the 'OPTIMIZED' mode.  For this mode a pixel is
- * treated as opaque only if the alpha value is equal to the maximum value.
- *
- * The final choice is to gamma encode the alpha channel as well.  This is
- * broken because, in practice, no implementation that uses this choice
- * correctly undoes the encoding before handling alpha composition.  Use this
- * choice only if other serious errors in the software or hardware you use
- * mandate it; the typical serious error is for dark halos to appear around
- * opaque areas of the composited PNG image because of arithmetic overflow.
- *
- * The API function png_set_alpha_mode specifies which of these choices to use
- * with an enumerated 'mode' value and the gamma of the required output:
- */
-#define PNG_ALPHA_PNG           0 /* according to the PNG standard */
-#define PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
-#define PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
-#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
-#define PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
-#define PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
-
-PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structp png_ptr, int mode,
-    double output_gamma));
-PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structp png_ptr,
-    int mode, png_fixed_point output_gamma));
-#endif
-
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-/* The output_gamma value is a screen gamma in libpng terminology: it expresses
- * how to decode the output values, not how they are encoded.  The values used
- * correspond to the normal numbers used to describe the overall gamma of a
- * computer display system; for example 2.2 for an sRGB conformant system.  The
- * values are scaled by 100000 in the _fixed version of the API (so 220000 for
- * sRGB.)
- *
- * The inverse of the value is always used to provide a default for the PNG file
- * encoding if it has no gAMA chunk and if png_set_gamma() has not been called
- * to override the PNG gamma information.
- *
- * When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
- * opaque pixels however pixels with lower alpha values are not encoded,
- * regardless of the output gamma setting.
- *
- * When the standard Porter Duff handling is requested with mode 1 the output
- * encoding is set to be linear and the output_gamma value is only relevant
- * as a default for input data that has no gamma information.  The linear output
- * encoding will be overridden if png_set_gamma() is called - the results may be
- * highly unexpected!
- *
- * The following numbers are derived from the sRGB standard and the research
- * behind it.  sRGB is defined to be approximated by a PNG gAMA chunk value of
- * 0.45455 (1/2.2) for PNG.  The value implicitly includes any viewing
- * correction required to take account of any differences in the color
- * environment of the original scene and the intended display environment; the
- * value expresses how to *decode* the image for display, not how the original
- * data was *encoded*.
- *
- * sRGB provides a peg for the PNG standard by defining a viewing environment.
- * sRGB itself, and earlier TV standards, actually use a more complex transform
- * (a linear portion then a gamma 2.4 power law) than PNG can express.  (PNG is
- * limited to simple power laws.)  By saying that an image for direct display on
- * an sRGB conformant system should be stored with a gAMA chunk value of 45455
- * (11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
- * makes it possible to derive values for other display systems and
- * environments.
- *
- * The Mac value is deduced from the sRGB based on an assumption that the actual
- * extra viewing correction used in early Mac display systems was implemented as
- * a power 1.45 lookup table.
- *
- * Any system where a programmable lookup table is used or where the behavior of
- * the final display device characteristics can be changed requires system
- * specific code to obtain the current characteristic.  However this can be
- * difficult and most PNG gamma correction only requires an approximate value.
- *
- * By default, if png_set_alpha_mode() is not called, libpng assumes that all
- * values are unencoded, linear, values and that the output device also has a
- * linear characteristic.  This is only very rarely correct - it is invariably
- * better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
- * default if you don't know what the right answer is!
- *
- * The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
- * 10.6) which used a correction table to implement a somewhat lower gamma on an
- * otherwise sRGB system.
- *
- * Both these values are reserved (not simple gamma values) in order to allow
- * more precise correction internally in the future.
- *
- * NOTE: the following values can be passed to either the fixed or floating
- * point APIs, but the floating point API will also accept floating point
- * values.
- */
-#define PNG_DEFAULT_sRGB -1       /* sRGB gamma and color space */
-#define PNG_GAMMA_MAC_18 -2       /* Old Mac '1.8' gamma and color space */
-#define PNG_GAMMA_sRGB   220000   /* Television standards--matches sRGB gamma */
-#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
-#endif
-
-/* The following are examples of calls to png_set_alpha_mode to achieve the
- * required overall gamma correction and, where necessary, alpha
- * premultiplication.
- *
- * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
- *    This is the default libpng handling of the alpha channel - it is not
- *    pre-multiplied into the color components.  In addition the call states
- *    that the output is for a sRGB system and causes all PNG files without gAMA
- *    chunks to be assumed to be encoded using sRGB.
- *
- * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
- *    In this case the output is assumed to be something like an sRGB conformant
- *    display preceeded by a power-law lookup table of power 1.45.  This is how
- *    early Mac systems behaved.
- *
- * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
- *    This is the classic Jim Blinn approach and will work in academic
- *    environments where everything is done by the book.  It has the shortcoming
- *    of assuming that input PNG data with no gamma information is linear - this
- *    is unlikely to be correct unless the PNG files where generated locally.
- *    Most of the time the output precision will be so low as to show
- *    significant banding in dark areas of the image.
- *
- * png_set_expand_16(pp);
- * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
- *    This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
- *    are assumed to have the sRGB encoding if not marked with a gamma value and
- *    the output is always 16 bits per component.  This permits accurate scaling
- *    and processing of the data.  If you know that your input PNG files were
- *    generated locally you might need to replace PNG_DEFAULT_sRGB with the
- *    correct value for your system.
- *
- * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
- *    If you just need to composite the PNG image onto an existing background
- *    and if you control the code that does this you can use the optimization
- *    setting.  In this case you just copy completely opaque pixels to the
- *    output.  For pixels that are not completely transparent (you just skip
- *    those) you do the composition math using png_composite or png_composite_16
- *    below then encode the resultant 8-bit or 16-bit values to match the output
- *    encoding.
- *
- * Other cases
- *    If neither the PNG nor the standard linear encoding work for you because
- *    of the software or hardware you use then you have a big problem.  The PNG
- *    case will probably result in halos around the image.  The linear encoding
- *    will probably result in a washed out, too bright, image (it's actually too
- *    contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
- *    substantially reduce the halos.  Alternatively try:
- *
- * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
- *    This option will also reduce the halos, but there will be slight dark
- *    halos round the opaque parts of the image where the background is light.
- *    In the OPTIMIZED mode the halos will be light halos where the background
- *    is dark.  Take your pick - the halos are unavoidable unless you can get
- *    your hardware/software fixed!  (The OPTIMIZED approach is slightly
- *    faster.)
- *
- * When the default gamma of PNG files doesn't match the output gamma.
- *    If you have PNG files with no gamma information png_set_alpha_mode allows
- *    you to provide a default gamma, but it also sets the ouput gamma to the
- *    matching value.  If you know your PNG files have a gamma that doesn't
- *    match the output you can take advantage of the fact that
- *    png_set_alpha_mode always sets the output gamma but only sets the PNG
- *    default if it is not already set:
- *
- * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
- * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
- *    The first call sets both the default and the output gamma values, the
- *    second call overrides the output gamma without changing the default.  This
- *    is easier than achieving the same effect with png_set_gamma.  You must use
- *    PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
- *    fire if more than one call to png_set_alpha_mode and png_set_background is
- *    made in the same read operation, however multiple calls with PNG_ALPHA_PNG
- *    are ignored.
- */
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-PNG_EXPORT(36, void, png_set_strip_alpha, (png_structp png_ptr));
-#endif
-
-#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
-    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
-PNG_EXPORT(37, void, png_set_swap_alpha, (png_structp png_ptr));
-#endif
-
-#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
-    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
-PNG_EXPORT(38, void, png_set_invert_alpha, (png_structp png_ptr));
-#endif
-
-#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
-/* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
-PNG_EXPORT(39, void, png_set_filler, (png_structp png_ptr, png_uint_32 filler,
-    int flags));
-/* The values of the PNG_FILLER_ defines should NOT be changed */
-#  define PNG_FILLER_BEFORE 0
-#  define PNG_FILLER_AFTER 1
-/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
-PNG_EXPORT(40, void, png_set_add_alpha,
-    (png_structp png_ptr, png_uint_32 filler,
-    int flags));
-#endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */
-
-#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
-/* Swap bytes in 16-bit depth files. */
-PNG_EXPORT(41, void, png_set_swap, (png_structp png_ptr));
-#endif
-
-#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
-/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
-PNG_EXPORT(42, void, png_set_packing, (png_structp png_ptr));
-#endif
-
-#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
-    defined(PNG_WRITE_PACKSWAP_SUPPORTED)
-/* Swap packing order of pixels in bytes. */
-PNG_EXPORT(43, void, png_set_packswap, (png_structp png_ptr));
-#endif
-
-#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
-/* Converts files to legal bit depths. */
-PNG_EXPORT(44, void, png_set_shift, (png_structp png_ptr, png_const_color_8p
-    true_bits));
-#endif
-
-#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
-    defined(PNG_WRITE_INTERLACING_SUPPORTED)
-/* Have the code handle the interlacing.  Returns the number of passes.
- * MUST be called before png_read_update_info or png_start_read_image,
- * otherwise it will not have the desired effect.  Note that it is still
- * necessary to call png_read_row or png_read_rows png_get_image_height
- * times for each pass.
-*/
-PNG_EXPORT(45, int, png_set_interlace_handling, (png_structp png_ptr));
-#endif
-
-#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
-/* Invert monochrome files */
-PNG_EXPORT(46, void, png_set_invert_mono, (png_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-/* Handle alpha and tRNS by replacing with a background color.  Prior to
- * libpng-1.5.4 this API must not be called before the PNG file header has been
- * read.  Doing so will result in unexpected behavior and possible warnings or
- * errors if the PNG file contains a bKGD chunk.
- */
-PNG_FP_EXPORT(47, void, png_set_background, (png_structp png_ptr,
-    png_const_color_16p background_color, int background_gamma_code,
-    int need_expand, double background_gamma));
-PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structp png_ptr,
-    png_const_color_16p background_color, int background_gamma_code,
-    int need_expand, png_fixed_point background_gamma));
-#endif
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-#  define PNG_BACKGROUND_GAMMA_UNKNOWN 0
-#  define PNG_BACKGROUND_GAMMA_SCREEN  1
-#  define PNG_BACKGROUND_GAMMA_FILE    2
-#  define PNG_BACKGROUND_GAMMA_UNIQUE  3
-#endif
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-/* Scale a 16-bit depth file down to 8-bit, accurately. */
-PNG_EXPORT(229, void, png_set_scale_16, (png_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-#define PNG_READ_16_TO_8 SUPPORTED /* Name prior to 1.5.4 */
-/* Strip the second byte of information from a 16-bit depth file. */
-PNG_EXPORT(48, void, png_set_strip_16, (png_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-/* Turn on quantizing, and reduce the palette to the number of colors
- * available.
- */
-PNG_EXPORT(49, void, png_set_quantize,
-    (png_structp png_ptr, png_colorp palette,
-    int num_palette, int maximum_colors, png_const_uint_16p histogram,
-    int full_quantize));
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-/* The threshold on gamma processing is configurable but hard-wired into the
- * library.  The following is the floating point variant.
- */
-#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
-
-/* Handle gamma correction. Screen_gamma=(display_exponent).
- * NOTE: this API simply sets the screen and file gamma values. It will
- * therefore override the value for gamma in a PNG file if it is called after
- * the file header has been read - use with care  - call before reading the PNG
- * file for best results!
- *
- * These routines accept the same gamma values as png_set_alpha_mode (described
- * above).  The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
- * API (floating point or fixed.)  Notice, however, that the 'file_gamma' value
- * is the inverse of a 'screen gamma' value.
- */
-PNG_FP_EXPORT(50, void, png_set_gamma,
-    (png_structp png_ptr, double screen_gamma,
-    double override_file_gamma));
-PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structp png_ptr,
-    png_fixed_point screen_gamma, png_fixed_point override_file_gamma));
-#endif
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-/* Set how many lines between output flushes - 0 for no flushing */
-PNG_EXPORT(51, void, png_set_flush, (png_structp png_ptr, int nrows));
-/* Flush the current PNG output buffer */
-PNG_EXPORT(52, void, png_write_flush, (png_structp png_ptr));
-#endif
-
-/* Optional update palette with requested transformations */
-PNG_EXPORT(53, void, png_start_read_image, (png_structp png_ptr));
-
-/* Optional call to update the users info structure */
-PNG_EXPORT(54, void, png_read_update_info,
-    (png_structp png_ptr, png_infop info_ptr));
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Read one or more rows of image data. */
-PNG_EXPORT(55, void, png_read_rows, (png_structp png_ptr, png_bytepp row,
-    png_bytepp display_row, png_uint_32 num_rows));
-#endif
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Read a row of data. */
-PNG_EXPORT(56, void, png_read_row, (png_structp png_ptr, png_bytep row,
-    png_bytep display_row));
-#endif
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Read the whole image into memory at once. */
-PNG_EXPORT(57, void, png_read_image, (png_structp png_ptr, png_bytepp image));
-#endif
-
-/* Write a row of image data */
-PNG_EXPORT(58, void, png_write_row,
-    (png_structp png_ptr, png_const_bytep row));
-
-/* Write a few rows of image data: (*row) is not written; however, the type
- * is declared as writeable to maintain compatibility with previous versions
- * of libpng and to allow the 'display_row' array from read_rows to be passed
- * unchanged to write_rows.
- */
-PNG_EXPORT(59, void, png_write_rows, (png_structp png_ptr, png_bytepp row,
-    png_uint_32 num_rows));
-
-/* Write the image data */
-PNG_EXPORT(60, void, png_write_image,
-    (png_structp png_ptr, png_bytepp image));
-
-/* Write the end of the PNG file. */
-PNG_EXPORT(61, void, png_write_end,
-    (png_structp png_ptr, png_infop info_ptr));
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Read the end of the PNG file. */
-PNG_EXPORT(62, void, png_read_end, (png_structp png_ptr, png_infop info_ptr));
-#endif
-
-/* Free any memory associated with the png_info_struct */
-PNG_EXPORT(63, void, png_destroy_info_struct, (png_structp png_ptr,
-    png_infopp info_ptr_ptr));
-
-/* Free any memory associated with the png_struct and the png_info_structs */
-PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
-    png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
-
-/* Free any memory associated with the png_struct and the png_info_structs */
-PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
-    png_infopp info_ptr_ptr));
-
-/* Set the libpng method of handling chunk CRC errors */
-PNG_EXPORT(66, void, png_set_crc_action,
-    (png_structp png_ptr, int crit_action, int ancil_action));
-
-/* Values for png_set_crc_action() say how to handle CRC errors in
- * ancillary and critical chunks, and whether to use the data contained
- * therein.  Note that it is impossible to "discard" data in a critical
- * chunk.  For versions prior to 0.90, the action was always error/quit,
- * whereas in version 0.90 and later, the action for CRC errors in ancillary
- * chunks is warn/discard.  These values should NOT be changed.
- *
- *      value                       action:critical     action:ancillary
- */
-#define PNG_CRC_DEFAULT       0  /* error/quit          warn/discard data */
-#define PNG_CRC_ERROR_QUIT    1  /* error/quit          error/quit        */
-#define PNG_CRC_WARN_DISCARD  2  /* (INVALID)           warn/discard data */
-#define PNG_CRC_WARN_USE      3  /* warn/use data       warn/use data     */
-#define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */
-#define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */
-
-/* These functions give the user control over the scan-line filtering in
- * libpng and the compression methods used by zlib.  These functions are
- * mainly useful for testing, as the defaults should work with most users.
- * Those users who are tight on memory or want faster performance at the
- * expense of compression can modify them.  See the compression library
- * header file (zlib.h) for an explination of the compression functions.
- */
-
-/* Set the filtering method(s) used by libpng.  Currently, the only valid
- * value for "method" is 0.
- */
-PNG_EXPORT(67, void, png_set_filter,
-    (png_structp png_ptr, int method, int filters));
-
-/* Flags for png_set_filter() to say which filters to use.  The flags
- * are chosen so that they don't conflict with real filter types
- * below, in case they are supplied instead of the #defined constants.
- * These values should NOT be changed.
- */
-#define PNG_NO_FILTERS     0x00
-#define PNG_FILTER_NONE    0x08
-#define PNG_FILTER_SUB     0x10
-#define PNG_FILTER_UP      0x20
-#define PNG_FILTER_AVG     0x40
-#define PNG_FILTER_PAETH   0x80
-#define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
-                         PNG_FILTER_AVG | PNG_FILTER_PAETH)
-
-/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
- * These defines should NOT be changed.
- */
-#define PNG_FILTER_VALUE_NONE  0
-#define PNG_FILTER_VALUE_SUB   1
-#define PNG_FILTER_VALUE_UP    2
-#define PNG_FILTER_VALUE_AVG   3
-#define PNG_FILTER_VALUE_PAETH 4
-#define PNG_FILTER_VALUE_LAST  5
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
-/* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
- * defines, either the default (minimum-sum-of-absolute-differences), or
- * the experimental method (weighted-minimum-sum-of-absolute-differences).
- *
- * Weights are factors >= 1.0, indicating how important it is to keep the
- * filter type consistent between rows.  Larger numbers mean the current
- * filter is that many times as likely to be the same as the "num_weights"
- * previous filters.  This is cumulative for each previous row with a weight.
- * There needs to be "num_weights" values in "filter_weights", or it can be
- * NULL if the weights aren't being specified.  Weights have no influence on
- * the selection of the first row filter.  Well chosen weights can (in theory)
- * improve the compression for a given image.
- *
- * Costs are factors >= 1.0 indicating the relative decoding costs of a
- * filter type.  Higher costs indicate more decoding expense, and are
- * therefore less likely to be selected over a filter with lower computational
- * costs.  There needs to be a value in "filter_costs" for each valid filter
- * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
- * setting the costs.  Costs try to improve the speed of decompression without
- * unduly increasing the compressed image size.
- *
- * A negative weight or cost indicates the default value is to be used, and
- * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
- * The default values for both weights and costs are currently 1.0, but may
- * change if good general weighting/cost heuristics can be found.  If both
- * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
- * to the UNWEIGHTED method, but with added encoding time/computation.
- */
-PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structp png_ptr,
-    int heuristic_method, int num_weights, png_const_doublep filter_weights,
-    png_const_doublep filter_costs));
-PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
-    (png_structp png_ptr,
-    int heuristic_method, int num_weights, png_const_fixed_point_p
-    filter_weights, png_const_fixed_point_p filter_costs));
-#endif /*  PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
-
-/* Heuristic used for row filter selection.  These defines should NOT be
- * changed.
- */
-#define PNG_FILTER_HEURISTIC_DEFAULT    0  /* Currently "UNWEIGHTED" */
-#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1  /* Used by libpng < 0.95 */
-#define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
-#define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */
-
-#ifdef PNG_WRITE_SUPPORTED
-/* Set the library compression level.  Currently, valid values range from
- * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
- * (0 - no compression, 9 - "maximal" compression).  Note that tests have
- * shown that zlib compression levels 3-6 usually perform as well as level 9
- * for PNG images, and do considerably fewer caclulations.  In the future,
- * these values may not correspond directly to the zlib compression levels.
- */
-PNG_EXPORT(69, void, png_set_compression_level,
-    (png_structp png_ptr, int level));
-
-PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structp png_ptr,
-    int mem_level));
-
-PNG_EXPORT(71, void, png_set_compression_strategy, (png_structp png_ptr,
-    int strategy));
-
-/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
- * smaller value of window_bits if it can do so safely.
- */
-PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structp png_ptr,
-    int window_bits));
-
-PNG_EXPORT(73, void, png_set_compression_method, (png_structp png_ptr,
-    int method));
-#endif
-
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
-/* Also set zlib parameters for compressing non-IDAT chunks */
-PNG_EXPORT(222, void, png_set_text_compression_level,
-    (png_structp png_ptr, int level));
-
-PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structp png_ptr,
-    int mem_level));
-
-PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structp png_ptr,
-    int strategy));
-
-/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
- * smaller value of window_bits if it can do so safely.
- */
-PNG_EXPORT(225, void, png_set_text_compression_window_bits, (png_structp
-    png_ptr, int window_bits));
-
-PNG_EXPORT(226, void, png_set_text_compression_method, (png_structp png_ptr,
-    int method));
-#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
-
-/* These next functions are called for input/output, memory, and error
- * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
- * and call standard C I/O routines such as fread(), fwrite(), and
- * fprintf().  These functions can be made to use other I/O routines
- * at run time for those applications that need to handle I/O in a
- * different manner by calling png_set_???_fn().  See libpng-manual.txt for
- * more information.
- */
-
-#ifdef PNG_STDIO_SUPPORTED
-/* Initialize the input/output for the PNG file to the default functions. */
-PNG_EXPORT(74, void, png_init_io, (png_structp png_ptr, png_FILE_p fp));
-#endif
-
-/* Replace the (error and abort), and warning functions with user
- * supplied functions.  If no messages are to be printed you must still
- * write and use replacement functions. The replacement error_fn should
- * still do a longjmp to the last setjmp location if you are using this
- * method of error handling.  If error_fn or warning_fn is NULL, the
- * default function will be used.
- */
-
-PNG_EXPORT(75, void, png_set_error_fn,
-    (png_structp png_ptr, png_voidp error_ptr,
-    png_error_ptr error_fn, png_error_ptr warning_fn));
-
-/* Return the user pointer associated with the error functions */
-PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structp png_ptr));
-
-/* Replace the default data output functions with a user supplied one(s).
- * If buffered output is not used, then output_flush_fn can be set to NULL.
- * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
- * output_flush_fn will be ignored (and thus can be NULL).
- * It is probably a mistake to use NULL for output_flush_fn if
- * write_data_fn is not also NULL unless you have built libpng with
- * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
- * default flush function, which uses the standard *FILE structure, will
- * be used.
- */
-PNG_EXPORT(77, void, png_set_write_fn, (png_structp png_ptr, png_voidp io_ptr,
-    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
-
-/* Replace the default data input function with a user supplied one. */
-PNG_EXPORT(78, void, png_set_read_fn, (png_structp png_ptr, png_voidp io_ptr,
-    png_rw_ptr read_data_fn));
-
-/* Return the user pointer associated with the I/O functions */
-PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_structp png_ptr));
-
-PNG_EXPORT(80, void, png_set_read_status_fn, (png_structp png_ptr,
-    png_read_status_ptr read_row_fn));
-
-PNG_EXPORT(81, void, png_set_write_status_fn, (png_structp png_ptr,
-    png_write_status_ptr write_row_fn));
-
-#ifdef PNG_USER_MEM_SUPPORTED
-/* Replace the default memory allocation functions with user supplied one(s). */
-PNG_EXPORT(82, void, png_set_mem_fn, (png_structp png_ptr, png_voidp mem_ptr,
-    png_malloc_ptr malloc_fn, png_free_ptr free_fn));
-/* Return the user pointer associated with the memory functions */
-PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structp png_ptr,
-    png_user_transform_ptr read_user_transform_fn));
-#endif
-
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structp png_ptr,
-    png_user_transform_ptr write_user_transform_fn));
-#endif
-
-#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-PNG_EXPORT(86, void, png_set_user_transform_info, (png_structp png_ptr,
-    png_voidp user_transform_ptr, int user_transform_depth,
-    int user_transform_channels));
-/* Return the user pointer associated with the user transform functions */
-PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
-    (png_const_structp png_ptr));
-#endif
-
-#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
-/* Return information about the row currently being processed.  Note that these
- * APIs do not fail but will return unexpected results if called outside a user
- * transform callback.  Also note that when transforming an interlaced image the
- * row number is the row number within the sub-image of the interlace pass, so
- * the value will increase to the height of the sub-image (not the full image)
- * then reset to 0 for the next pass.
- *
- * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
- * find the output pixel (x,y) given an interlaced sub-image pixel
- * (row,col,pass).  (See below for these macros.)
- */
-PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structp));
-PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structp));
-#endif
-
-#ifdef PNG_USER_CHUNKS_SUPPORTED
-PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structp png_ptr,
-    png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
-PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structp png_ptr));
-#endif
-
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-/* Sets the function callbacks for the push reader, and a pointer to a
- * user-defined structure available to the callback functions.
- */
-PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structp png_ptr,
-    png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
-    png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
-
-/* Returns the user pointer associated with the push read functions */
-PNG_EXPORT(91, png_voidp, png_get_progressive_ptr, (png_const_structp png_ptr));
-
-/* Function to be called when data becomes available */
-PNG_EXPORT(92, void, png_process_data,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_bytep buffer, png_size_t buffer_size));
-
-/* A function which may be called *only* within png_process_data to stop the
- * processing of any more data.  The function returns the number of bytes
- * remaining, excluding any that libpng has cached internally.  A subsequent
- * call to png_process_data must supply these bytes again.  If the argument
- * 'save' is set to true the routine will first save all the pending data and
- * will always return 0.
- */
-PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structp, int save));
-
-/* A function which may be called *only* outside (after) a call to
- * png_process_data.  It returns the number of bytes of data to skip in the
- * input.  Normally it will return 0, but if it returns a non-zero value the
- * application must skip than number of bytes of input data and pass the
- * following data to the next call to png_process_data.
- */
-PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structp));
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-/* Function that combines rows.  'new_row' is a flag that should come from
- * the callback and be non-NULL if anything needs to be done; the library
- * stores its own version of the new data internally and ignores the passed
- * in value.
- */
-PNG_EXPORT(93, void, png_progressive_combine_row, (png_structp png_ptr,
-    png_bytep old_row, png_const_bytep new_row));
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
-
-PNG_EXPORTA(94, png_voidp, png_malloc,
-    (png_structp png_ptr, png_alloc_size_t size),
-    PNG_ALLOCATED);
-/* Added at libpng version 1.4.0 */
-PNG_EXPORTA(95, png_voidp, png_calloc,
-    (png_structp png_ptr, png_alloc_size_t size),
-    PNG_ALLOCATED);
-
-/* Added at libpng version 1.2.4 */
-PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_structp png_ptr,
-    png_alloc_size_t size), PNG_ALLOCATED);
-
-/* Frees a pointer allocated by png_malloc() */
-PNG_EXPORT(97, void, png_free, (png_structp png_ptr, png_voidp ptr));
-
-/* Free data that was allocated internally */
-PNG_EXPORT(98, void, png_free_data,
-    (png_structp png_ptr, png_infop info_ptr, png_uint_32 free_me, int num));
-
-/* Reassign responsibility for freeing existing data, whether allocated
- * by libpng or by the application */
-PNG_EXPORT(99, void, png_data_freer,
-    (png_structp png_ptr, png_infop info_ptr, int freer, png_uint_32 mask));
-
-/* Assignments for png_data_freer */
-#define PNG_DESTROY_WILL_FREE_DATA 1
-#define PNG_SET_WILL_FREE_DATA 1
-#define PNG_USER_WILL_FREE_DATA 2
-/* Flags for png_ptr->free_me and info_ptr->free_me */
-#define PNG_FREE_HIST 0x0008
-#define PNG_FREE_ICCP 0x0010
-#define PNG_FREE_SPLT 0x0020
-#define PNG_FREE_ROWS 0x0040
-#define PNG_FREE_PCAL 0x0080
-#define PNG_FREE_SCAL 0x0100
-#define PNG_FREE_UNKN 0x0200
-#define PNG_FREE_LIST 0x0400
-#define PNG_FREE_PLTE 0x1000
-#define PNG_FREE_TRNS 0x2000
-#define PNG_FREE_TEXT 0x4000
-#define PNG_FREE_ALL  0x7fff
-#define PNG_FREE_MUL  0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
-
-#ifdef PNG_USER_MEM_SUPPORTED
-PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_structp png_ptr,
-    png_alloc_size_t size), PNG_ALLOCATED);
-PNG_EXPORT(101, void, png_free_default, (png_structp png_ptr, png_voidp ptr));
-#endif
-
-#ifdef PNG_ERROR_TEXT_SUPPORTED
-/* Fatal error in PNG image of libpng - can't continue */
-PNG_EXPORTA(102, void, png_error,
-    (png_structp png_ptr, png_const_charp error_message),
-    PNG_NORETURN);
-
-/* The same, but the chunk name is prepended to the error string. */
-PNG_EXPORTA(103, void, png_chunk_error, (png_structp png_ptr,
-    png_const_charp error_message), PNG_NORETURN);
-
-#else
-/* Fatal error in PNG image of libpng - can't continue */
-PNG_EXPORTA(104, void, png_err, (png_structp png_ptr), PNG_NORETURN);
-#endif
-
-#ifdef PNG_WARNINGS_SUPPORTED
-/* Non-fatal error in libpng.  Can continue, but may have a problem. */
-PNG_EXPORT(105, void, png_warning, (png_structp png_ptr,
-    png_const_charp warning_message));
-
-/* Non-fatal error in libpng, chunk name is prepended to message. */
-PNG_EXPORT(106, void, png_chunk_warning, (png_structp png_ptr,
-    png_const_charp warning_message));
-#endif
-
-#ifdef PNG_BENIGN_ERRORS_SUPPORTED
-/* Benign error in libpng.  Can continue, but may have a problem.
- * User can choose whether to handle as a fatal error or as a warning. */
-#  undef png_benign_error
-PNG_EXPORT(107, void, png_benign_error, (png_structp png_ptr,
-    png_const_charp warning_message));
-
-/* Same, chunk name is prepended to message. */
-#  undef png_chunk_benign_error
-PNG_EXPORT(108, void, png_chunk_benign_error, (png_structp png_ptr,
-    png_const_charp warning_message));
-
-PNG_EXPORT(109, void, png_set_benign_errors,
-    (png_structp png_ptr, int allowed));
-#else
-#  ifdef PNG_ALLOW_BENIGN_ERRORS
-#    define png_benign_error png_warning
-#    define png_chunk_benign_error png_chunk_warning
-#  else
-#    define png_benign_error png_error
-#    define png_chunk_benign_error png_chunk_error
-#  endif
-#endif
-
-/* The png_set_<chunk> functions are for storing values in the png_info_struct.
- * Similarly, the png_get_<chunk> calls are used to read values from the
- * png_info_struct, either storing the parameters in the passed variables, or
- * setting pointers into the png_info_struct where the data is stored.  The
- * png_get_<chunk> functions return a non-zero value if the data was available
- * in info_ptr, or return zero and do not change any of the parameters if the
- * data was not available.
- *
- * These functions should be used instead of directly accessing png_info
- * to avoid problems with future changes in the size and internal layout of
- * png_info_struct.
- */
-/* Returns "flag" if chunk data is valid in info_ptr. */
-PNG_EXPORT(110, png_uint_32, png_get_valid,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_uint_32 flag));
-
-/* Returns number of bytes needed to hold a transformed row. */
-PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structp png_ptr,
-    png_const_infop info_ptr));
-
-#ifdef PNG_INFO_IMAGE_SUPPORTED
-/* Returns row_pointers, which is an array of pointers to scanlines that was
- * returned from png_read_png().
- */
-PNG_EXPORT(112, png_bytepp, png_get_rows,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-/* Set row_pointers, which is an array of pointers to scanlines for use
- * by png_write_png().
- */
-PNG_EXPORT(113, void, png_set_rows, (png_structp png_ptr,
-    png_infop info_ptr, png_bytepp row_pointers));
-#endif
-
-/* Returns number of color channels in image. */
-PNG_EXPORT(114, png_byte, png_get_channels,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-
-#ifdef PNG_EASY_ACCESS_SUPPORTED
-/* Returns image width in pixels. */
-PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structp png_ptr,
-    png_const_infop info_ptr));
-
-/* Returns image height in pixels. */
-PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structp png_ptr,
-    png_const_infop info_ptr));
-
-/* Returns image bit_depth. */
-PNG_EXPORT(117, png_byte, png_get_bit_depth,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-
-/* Returns image color_type. */
-PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structp png_ptr,
-    png_const_infop info_ptr));
-
-/* Returns image filter_type. */
-PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structp png_ptr,
-    png_const_infop info_ptr));
-
-/* Returns image interlace_type. */
-PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structp png_ptr,
-    png_const_infop info_ptr));
-
-/* Returns image compression_type. */
-PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structp png_ptr,
-    png_const_infop info_ptr));
-
-/* Returns image resolution in pixels per meter, from pHYs chunk data. */
-PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-
-/* Returns pixel aspect ratio, computed from pHYs chunk data.  */
-PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-
-/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
-PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-
-#endif /* PNG_EASY_ACCESS_SUPPORTED */
-
-/* Returns pointer to signature string read from PNG header */
-PNG_EXPORT(130, png_const_bytep, png_get_signature,
-    (png_const_structp png_ptr, png_infop info_ptr));
-
-#ifdef PNG_bKGD_SUPPORTED
-PNG_EXPORT(131, png_uint_32, png_get_bKGD,
-    (png_const_structp png_ptr, png_infop info_ptr,
-    png_color_16p *background));
-#endif
-
-#ifdef PNG_bKGD_SUPPORTED
-PNG_EXPORT(132, void, png_set_bKGD, (png_structp png_ptr, png_infop info_ptr,
-    png_const_color_16p background));
-#endif
-
-#ifdef PNG_cHRM_SUPPORTED
-PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structp png_ptr,
-   png_const_infop info_ptr, double *white_x, double *white_y, double *red_x,
-    double *red_y, double *green_x, double *green_y, double *blue_x,
-    double *blue_y));
-PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_structp png_ptr,
-    png_const_infop info_ptr, double *red_X, double *red_Y, double *red_Z,
-    double *green_X, double *green_Y, double *green_Z, double *blue_X,
-    double *blue_Y, double *blue_Z));
-#ifdef PNG_FIXED_POINT_SUPPORTED /* Otherwise not implemented */
-PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
-    (png_const_structp png_ptr,
-    png_const_infop info_ptr, png_fixed_point *int_white_x,
-    png_fixed_point *int_white_y, png_fixed_point *int_red_x,
-    png_fixed_point *int_red_y, png_fixed_point *int_green_x,
-    png_fixed_point *int_green_y, png_fixed_point *int_blue_x,
-    png_fixed_point *int_blue_y));
-#endif
-PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
-    (png_structp png_ptr, png_const_infop info_ptr,
-    png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
-    png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
-    png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
-    png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
-    png_fixed_point *int_blue_Z));
-#endif
-
-#ifdef PNG_cHRM_SUPPORTED
-PNG_FP_EXPORT(135, void, png_set_cHRM,
-    (png_structp png_ptr, png_infop info_ptr,
-    double white_x, double white_y, double red_x, double red_y, double green_x,
-    double green_y, double blue_x, double blue_y));
-PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_structp png_ptr,
-    png_infop info_ptr, double red_X, double red_Y, double red_Z,
-    double green_X, double green_Y, double green_Z, double blue_X,
-    double blue_Y, double blue_Z));
-PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_structp png_ptr,
-    png_infop info_ptr, png_fixed_point int_white_x,
-    png_fixed_point int_white_y, png_fixed_point int_red_x,
-    png_fixed_point int_red_y, png_fixed_point int_green_x,
-    png_fixed_point int_green_y, png_fixed_point int_blue_x,
-    png_fixed_point int_blue_y));
-PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_structp png_ptr,
-    png_infop info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
-    png_fixed_point int_red_Z, png_fixed_point int_green_X,
-    png_fixed_point int_green_Y, png_fixed_point int_green_Z,
-    png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
-    png_fixed_point int_blue_Z));
-#endif
-
-#ifdef PNG_gAMA_SUPPORTED
-PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    double *file_gamma));
-PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_fixed_point *int_file_gamma));
-#endif
-
-#ifdef PNG_gAMA_SUPPORTED
-PNG_FP_EXPORT(139, void, png_set_gAMA, (png_structp png_ptr,
-    png_infop info_ptr, double file_gamma));
-PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_structp png_ptr,
-    png_infop info_ptr, png_fixed_point int_file_gamma));
-#endif
-
-#ifdef PNG_hIST_SUPPORTED
-PNG_EXPORT(141, png_uint_32, png_get_hIST,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_uint_16p *hist));
-#endif
-
-#ifdef PNG_hIST_SUPPORTED
-PNG_EXPORT(142, void, png_set_hIST, (png_structp png_ptr,
-    png_infop info_ptr, png_const_uint_16p hist));
-#endif
-
-PNG_EXPORT(143, png_uint_32, png_get_IHDR,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 *width, png_uint_32 *height, int *bit_depth, int *color_type,
-    int *interlace_method, int *compression_method, int *filter_method));
-
-PNG_EXPORT(144, void, png_set_IHDR,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
-    int interlace_method, int compression_method, int filter_method));
-
-#ifdef PNG_oFFs_SUPPORTED
-PNG_EXPORT(145, png_uint_32, png_get_oFFs,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type));
-#endif
-
-#ifdef PNG_oFFs_SUPPORTED
-PNG_EXPORT(146, void, png_set_oFFs,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_int_32 offset_x, png_int_32 offset_y, int unit_type));
-#endif
-
-#ifdef PNG_pCAL_SUPPORTED
-PNG_EXPORT(147, png_uint_32, png_get_pCAL,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type,
-    int *nparams,
-    png_charp *units, png_charpp *params));
-#endif
-
-#ifdef PNG_pCAL_SUPPORTED
-PNG_EXPORT(148, void, png_set_pCAL, (png_structp png_ptr,
-    png_infop info_ptr,
-    png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type,
-    int nparams, png_const_charp units, png_charpp params));
-#endif
-
-#ifdef PNG_pHYs_SUPPORTED
-PNG_EXPORT(149, png_uint_32, png_get_pHYs,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));
-#endif
-
-#ifdef PNG_pHYs_SUPPORTED
-PNG_EXPORT(150, void, png_set_pHYs,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 res_x, png_uint_32 res_y, int unit_type));
-#endif
-
-PNG_EXPORT(151, png_uint_32, png_get_PLTE,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_colorp *palette, int *num_palette));
-
-PNG_EXPORT(152, void, png_set_PLTE,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_const_colorp palette, int num_palette));
-
-#ifdef PNG_sBIT_SUPPORTED
-PNG_EXPORT(153, png_uint_32, png_get_sBIT,
-    (png_const_structp png_ptr, png_infop info_ptr,
-    png_color_8p *sig_bit));
-#endif
-
-#ifdef PNG_sBIT_SUPPORTED
-PNG_EXPORT(154, void, png_set_sBIT,
-    (png_structp png_ptr, png_infop info_ptr, png_const_color_8p sig_bit));
-#endif
-
-#ifdef PNG_sRGB_SUPPORTED
-PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structp png_ptr,
-    png_const_infop info_ptr, int *file_srgb_intent));
-#endif
-
-#ifdef PNG_sRGB_SUPPORTED
-PNG_EXPORT(156, void, png_set_sRGB,
-    (png_structp png_ptr, png_infop info_ptr, int srgb_intent));
-PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_structp png_ptr,
-    png_infop info_ptr, int srgb_intent));
-#endif
-
-#ifdef PNG_iCCP_SUPPORTED
-PNG_EXPORT(158, png_uint_32, png_get_iCCP,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_charpp name, int *compression_type, png_bytepp profile,
-    png_uint_32 *proflen));
-#endif
-
-#ifdef PNG_iCCP_SUPPORTED
-PNG_EXPORT(159, void, png_set_iCCP,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_const_charp name, int compression_type, png_const_bytep profile,
-    png_uint_32 proflen));
-#endif
-
-#ifdef PNG_sPLT_SUPPORTED
-PNG_EXPORT(160, png_uint_32, png_get_sPLT,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_sPLT_tpp entries));
-#endif
-
-#ifdef PNG_sPLT_SUPPORTED
-PNG_EXPORT(161, void, png_set_sPLT,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_const_sPLT_tp entries, int nentries));
-#endif
-
-#ifdef PNG_TEXT_SUPPORTED
-/* png_get_text also returns the number of text chunks in *num_text */
-PNG_EXPORT(162, png_uint_32, png_get_text,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    png_textp *text_ptr, int *num_text));
-#endif
-
-/* Note while png_set_text() will accept a structure whose text,
- * language, and  translated keywords are NULL pointers, the structure
- * returned by png_get_text will always contain regular
- * zero-terminated C strings.  They might be empty strings but
- * they will never be NULL pointers.
- */
-
-#ifdef PNG_TEXT_SUPPORTED
-PNG_EXPORT(163, void, png_set_text,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_const_textp text_ptr, int num_text));
-#endif
-
-#ifdef PNG_tIME_SUPPORTED
-PNG_EXPORT(164, png_uint_32, png_get_tIME,
-    (png_const_structp png_ptr, png_infop info_ptr, png_timep *mod_time));
-#endif
-
-#ifdef PNG_tIME_SUPPORTED
-PNG_EXPORT(165, void, png_set_tIME,
-    (png_structp png_ptr, png_infop info_ptr, png_const_timep mod_time));
-#endif
-
-#ifdef PNG_tRNS_SUPPORTED
-PNG_EXPORT(166, png_uint_32, png_get_tRNS,
-    (png_const_structp png_ptr, png_infop info_ptr,
-    png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color));
-#endif
-
-#ifdef PNG_tRNS_SUPPORTED
-PNG_EXPORT(167, void, png_set_tRNS,
-    (png_structp png_ptr, png_infop info_ptr,
-    png_const_bytep trans_alpha, int num_trans,
-    png_const_color_16p trans_color));
-#endif
-
-#ifdef PNG_sCAL_SUPPORTED
-PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    int *unit, double *width, double *height));
-#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-/* NOTE: this API is currently implemented using floating point arithmetic,
- * consequently it can only be used on systems with floating point support.
- * In any case the range of values supported by png_fixed_point is small and it
- * is highly recommended that png_get_sCAL_s be used instead.
- */
-PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
-    (png_structp png_ptr, png_const_infop info_ptr, int *unit,
-    png_fixed_point *width,
-    png_fixed_point *height));
-#endif
-PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
-    (png_const_structp png_ptr, png_const_infop info_ptr,
-    int *unit, png_charpp swidth, png_charpp sheight));
-
-PNG_FP_EXPORT(170, void, png_set_sCAL,
-    (png_structp png_ptr, png_infop info_ptr,
-    int unit, double width, double height));
-PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_structp png_ptr,
-   png_infop info_ptr, int unit, png_fixed_point width,
-   png_fixed_point height));
-PNG_EXPORT(171, void, png_set_sCAL_s,
-    (png_structp png_ptr, png_infop info_ptr,
-    int unit, png_const_charp swidth, png_const_charp sheight));
-#endif /* PNG_sCAL_SUPPORTED */
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-/* Provide a list of chunks and how they are to be handled, if the built-in
-   handling or default unknown chunk handling is not desired.  Any chunks not
-   listed will be handled in the default manner.  The IHDR and IEND chunks
-   must not be listed.  Because this turns off the default handling for chunks
-   that would otherwise be recognized the behavior of libpng transformations may
-   well become incorrect!
-      keep = 0: PNG_HANDLE_CHUNK_AS_DEFAULT: follow default behavior
-           = 1: PNG_HANDLE_CHUNK_NEVER:      do not keep
-           = 2: PNG_HANDLE_CHUNK_IF_SAFE:    keep only if safe-to-copy
-           = 3: PNG_HANDLE_CHUNK_ALWAYS:     keep even if unsafe-to-copy
-*/
-PNG_EXPORT(172, void, png_set_keep_unknown_chunks,
-    (png_structp png_ptr, int keep,
-    png_const_bytep chunk_list, int num_chunks));
-
-/* The handling code is returned; the result is therefore true (non-zero) if
- * special handling is required, false for the default handling.
- */
-PNG_EXPORT(173, int, png_handle_as_unknown, (png_structp png_ptr,
-    png_const_bytep chunk_name));
-#endif
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-PNG_EXPORT(174, void, png_set_unknown_chunks, (png_structp png_ptr,
-    png_infop info_ptr, png_const_unknown_chunkp unknowns,
-    int num_unknowns));
-PNG_EXPORT(175, void, png_set_unknown_chunk_location,
-    (png_structp png_ptr, png_infop info_ptr, int chunk, int location));
-PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structp png_ptr,
-    png_const_infop info_ptr, png_unknown_chunkpp entries));
-#endif
-
-/* Png_free_data() will turn off the "valid" flag for anything it frees.
- * If you need to turn it off for a chunk that your application has freed,
- * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
- */
-PNG_EXPORT(177, void, png_set_invalid,
-    (png_structp png_ptr, png_infop info_ptr, int mask));
-
-#ifdef PNG_INFO_IMAGE_SUPPORTED
-/* The "params" pointer is currently not used and is for future expansion. */
-PNG_EXPORT(178, void, png_read_png, (png_structp png_ptr, png_infop info_ptr,
-    int transforms, png_voidp params));
-PNG_EXPORT(179, void, png_write_png, (png_structp png_ptr, png_infop info_ptr,
-    int transforms, png_voidp params));
-#endif
-
-PNG_EXPORT(180, png_const_charp, png_get_copyright,
-    (png_const_structp png_ptr));
-PNG_EXPORT(181, png_const_charp, png_get_header_ver,
-    (png_const_structp png_ptr));
-PNG_EXPORT(182, png_const_charp, png_get_header_version,
-    (png_const_structp png_ptr));
-PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
-    (png_const_structp png_ptr));
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structp png_ptr,
-    png_uint_32 mng_features_permitted));
-#endif
-
-/* For use in png_set_keep_unknown, added to version 1.2.6 */
-#define PNG_HANDLE_CHUNK_AS_DEFAULT   0
-#define PNG_HANDLE_CHUNK_NEVER        1
-#define PNG_HANDLE_CHUNK_IF_SAFE      2
-#define PNG_HANDLE_CHUNK_ALWAYS       3
-
-/* Strip the prepended error numbers ("#nnn ") from error and warning
- * messages before passing them to the error or warning handler.
- */
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
-PNG_EXPORT(185, void, png_set_strip_error_numbers,
-    (png_structp png_ptr,
-    png_uint_32 strip_mode));
-#endif
-
-/* Added in libpng-1.2.6 */
-#ifdef PNG_SET_USER_LIMITS_SUPPORTED
-PNG_EXPORT(186, void, png_set_user_limits, (png_structp png_ptr,
-    png_uint_32 user_width_max, png_uint_32 user_height_max));
-PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
-    (png_const_structp png_ptr));
-PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
-    (png_const_structp png_ptr));
-/* Added in libpng-1.4.0 */
-PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structp png_ptr,
-    png_uint_32 user_chunk_cache_max));
-PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
-    (png_const_structp png_ptr));
-/* Added in libpng-1.4.1 */
-PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structp png_ptr,
-    png_alloc_size_t user_chunk_cache_max));
-PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
-    (png_const_structp png_ptr));
-#endif
-
-#if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
-PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-
-PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-
-PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-
-PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
-    (png_const_structp png_ptr, png_const_infop info_ptr));
-#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
-PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
-    (png_structp png_ptr, png_const_infop info_ptr));
-#endif
-
-PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structp png_ptr,
-    png_const_infop info_ptr));
-#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
-PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
-    (png_structp png_ptr, png_const_infop info_ptr));
-#endif
-
-#  ifdef PNG_pHYs_SUPPORTED
-PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structp png_ptr,
-    png_const_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
-    int *unit_type));
-#  endif /* PNG_pHYs_SUPPORTED */
-#endif  /* PNG_INCH_CONVERSIONS_SUPPORTED */
-
-/* Added in libpng-1.4.0 */
-#ifdef PNG_IO_STATE_SUPPORTED
-PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_structp png_ptr));
-
-PNG_EXPORTA(200, png_const_bytep, png_get_io_chunk_name,
-    (png_structp png_ptr), PNG_DEPRECATED);
-PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
-    (png_const_structp png_ptr));
-
-/* The flags returned by png_get_io_state() are the following: */
-#  define PNG_IO_NONE        0x0000   /* no I/O at this moment */
-#  define PNG_IO_READING     0x0001   /* currently reading */
-#  define PNG_IO_WRITING     0x0002   /* currently writing */
-#  define PNG_IO_SIGNATURE   0x0010   /* currently at the file signature */
-#  define PNG_IO_CHUNK_HDR   0x0020   /* currently at the chunk header */
-#  define PNG_IO_CHUNK_DATA  0x0040   /* currently at the chunk data */
-#  define PNG_IO_CHUNK_CRC   0x0080   /* currently at the chunk crc */
-#  define PNG_IO_MASK_OP     0x000f   /* current operation: reading/writing */
-#  define PNG_IO_MASK_LOC    0x00f0   /* current location: sig/hdr/data/crc */
-#endif /* ?PNG_IO_STATE_SUPPORTED */
-
-/* Interlace support.  The following macros are always defined so that if
- * libpng interlace handling is turned off the macros may be used to handle
- * interlaced images within the application.
- */
-#define PNG_INTERLACE_ADAM7_PASSES 7
-
-/* Two macros to return the first row and first column of the original,
- * full, image which appears in a given pass.  'pass' is in the range 0
- * to 6 and the result is in the range 0 to 7.
- */
-#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
-#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
-
-/* A macro to return the offset between pixels in the output row for a pair of
- * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
- * follows.  Note that ROW_OFFSET is the offset from one row to the next whereas
- * COL_OFFSET is from one column to the next, within a row.
- */
-#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
-#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
-
-/* Two macros to help evaluate the number of rows or columns in each
- * pass.  This is expressed as a shift - effectively log2 of the number or
- * rows or columns in each 8x8 tile of the original image.
- */
-#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
-#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
-
-/* Hence two macros to determine the number of rows or columns in a given
- * pass of an image given its height or width.  In fact these macros may
- * return non-zero even though the sub-image is empty, because the other
- * dimension may be empty for a small image.
- */
-#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
-   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
-#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
-   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
-
-/* For the reader row callbacks (both progressive and sequential) it is
- * necessary to find the row in the output image given a row in an interlaced
- * image, so two more macros:
- */
-#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
-   (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
-#define PNG_COL_FROM_PASS_COL(xIn, pass) \
-   (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
-
-/* Two macros which return a boolean (0 or 1) saying whether the given row
- * or column is in a particular pass.  These use a common utility macro that
- * returns a mask for a given pass - the offset 'off' selects the row or
- * column version.  The mask has the appropriate bit set for each column in
- * the tile.
- */
-#define PNG_PASS_MASK(pass,off) ( \
-   ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
-   ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
-
-#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
-   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
-#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
-   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
-
-#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
-/* With these routines we avoid an integer divide, which will be slower on
- * most machines.  However, it does take more operations than the corresponding
- * divide method, so it may be slower on a few RISC systems.  There are two
- * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
- *
- * Note that the rounding factors are NOT supposed to be the same!  128 and
- * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
- * standard method.
- *
- * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
- */
-
- /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
-
-#  define png_composite(composite, fg, alpha, bg)         \
-     { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
-           * (png_uint_16)(alpha)                         \
-           + (png_uint_16)(bg)*(png_uint_16)(255          \
-           - (png_uint_16)(alpha)) + 128);                \
-       (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
-
-#  define png_composite_16(composite, fg, alpha, bg)       \
-     { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg)  \
-           * (png_uint_32)(alpha)                          \
-           + (png_uint_32)(bg)*(65535                      \
-           - (png_uint_32)(alpha)) + 32768);               \
-       (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
-
-#else  /* Standard method using integer division */
-
-#  define png_composite(composite, fg, alpha, bg)                          \
-     (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) +  \
-     (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) +       \
-     127) / 255)
-
-#  define png_composite_16(composite, fg, alpha, bg)                         \
-     (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
-     (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) +         \
-     32767) / 65535)
-#endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
-
-#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
-PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
-PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
-PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
-#endif
-
-PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_structp png_ptr,
-    png_const_bytep buf));
-/* No png_get_int_16 -- may be added if there's a real need for it. */
-
-/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
-#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
-PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
-#endif
-#ifdef PNG_SAVE_INT_32_SUPPORTED
-PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
-#endif
-
-/* Place a 16-bit number into a buffer in PNG byte order.
- * The parameter is declared unsigned int, not png_uint_16,
- * just to avoid potential problems on pre-ANSI C compilers.
- */
-#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
-PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
-/* No png_save_int_16 -- may be added if there's a real need for it. */
-#endif
-
-#ifdef PNG_USE_READ_MACROS
-/* Inline macros to do direct reads of bytes from the input buffer.
- * The png_get_int_32() routine assumes we are using two's complement
- * format for negative values, which is almost certainly true.
- */
-#  define png_get_uint_32(buf) \
-     (((png_uint_32)(*(buf)) << 24) + \
-      ((png_uint_32)(*((buf) + 1)) << 16) + \
-      ((png_uint_32)(*((buf) + 2)) << 8) + \
-      ((png_uint_32)(*((buf) + 3))))
-
-   /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
-    * function) incorrectly returned a value of type png_uint_32.
-    */
-#  define png_get_uint_16(buf) \
-     ((png_uint_16) \
-      (((unsigned int)(*(buf)) << 8) + \
-       ((unsigned int)(*((buf) + 1)))))
-
-#  define png_get_int_32(buf) \
-     ((png_int_32)((*(buf) & 0x80) \
-      ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
-      : (png_int_32)png_get_uint_32(buf)))
-#endif
-
-#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
-    defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
-PNG_EXPORT(234, void, png_set_check_for_invalid_index, (png_structp png_ptr,
-    int allowed));
-#endif
-
-/* Maintainer: Put new public prototypes here ^, in libpng.3, and project
- * defs
- */
-
-/* The last ordinal number (this is the *last* one already used; the next
- * one to use is one more than this.)  Maintainer, remember to add an entry to
- * scripts/symbols.def as well.
- */
-#ifdef PNG_EXPORT_LAST_ORDINAL
-  PNG_EXPORT_LAST_ORDINAL(234);
-#endif
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* PNG_VERSION_INFO_ONLY */
-/* Do not put anything past this line */
-#endif /* PNG_H */
diff --git a/extern/libpng/include/pngbar.jpg b/extern/libpng/include/pngbar.jpg
deleted file mode 100644
index 70ba8d817ce433788c7933dbe3c29c3e384b2b0a..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 2498
zcmb79cR1UN8ve<!Vud7}HYCK}tM;Y{Z5^vrsFE6uJ&GDt6fJ6Y=`oAe-h^XIQ7v*#
zZO1A~(WaF)HOtle+~>LX-}`>=f8Y0x?_}m=8Q`%n#hU_5OiaM90Zxtq1>=CgTfsNH
zyhE`{nwsjeShHXcFRV>~hi`yq2v*YHBRtd~Fu*+^LY^4lCw1}<U<`mkpkF)%<djfW
zC=>#Lva_%-vvRO=aKPAMFitLB9!@Se7YxRO;(_xakVqs4H@^T1A;613B7T`LfloCM
zC>s>YhTw#8BK~ij^a5~J00TIJnM42(oCyqPI(Y@00RRyA^t=CpnFWBbLcymyB_03-
z0x_M|W@3T<`-BN}TAvxt!Yd50@*zZ&*pN77LnCW9lz^y8aNMcnEYqn3{J(Y(W-t^0
zvHZ$XfCC^V5CqH&h5jdw2?Phg5ME(JD6^7?wOdfuSH8H0zP}N;;+36~Ie_ET2?Phj
z0ewJu_XPOzrM!FkVBFSWa?9PHSVQF9@l6YED#^WWRML1J9VDQieoKN{=G;@B(Vmqw
zMZd`y)ni0|7a{dGH#QBu4Xb>^8Ml-38dtbR*{4J6CiE}A`n<^Swi_b~53dp@Oz5&x
zqIb>@R2bY|^Eg5Q^oZrcolUy~e~ev4`E;SpK(~nwOpGHYx7IEN6TgtCZ%ql2@{}O=
zB=jD|t!NkbZ`gujXu2t1GZEV?OI;QB^sVbc{HllYU92vX0u%;zs?5Dy7i5b^Vr}Pn
zO2G4GXu7^$QmgA^)I4+H4Ve#&F8{pR>+ENwX4HwzetiUp&~J{h-wxp)&2&qMG9ULl
z$1sGXW1&H@50#Izy=lZUfjypz`|x(CS!BmIDmt4<-iM+7vJJYh6Ok&Y`9uL<Z7G&l
z=3{Ft5*;tKL?$<)?4vlk;&S(F^p?OABxel=x4PsX`WCZ|W62+S?$a?rPIXSZEfap*
zCA#P4K5cAmskO?sY&lfF8?d~sK}__NwBcG0#y>Dz-dii|{T@&nMOnhYGW-(Yq<%v=
zZ{=JMeWTwA?P4UG8a$$%3#A_D7*<`B{srsRec$8y$6ez;HO0+<=@)~a+C#KD$fFie
zOF5lh(}n6`?kJ=#rB8?(qO_~`d`n%$zP0)o`DHOCeo?6M-Pn1fN6p1D_{#*0&JIPU
zL@9JFTVPL!MG(xN{Pyi$)cs@-UVOt7&mCx*p!Qt+LYRr<MCQctCLjHK$pfn;z1hy?
zhFmm?j52ZVvPpd!#yTf?y@~zp8GfD<V5X=(OGEIkLe9d<@#vRl>oDYFGACZJ{8Pxa
zhc4YRL#jc2?yi*%aQ(San~2E>x<f&P-V^$lGs#wBuczC`M-$FkId!>W1QR0J9uq>9
zE|N+~DEC)g{=F~&W?nheQJ?`Q<2i%Wz?M||p-DL5&AOs`qIe3z=N#%2ExTl7#Mi~t
zZT<r>vmnY2L6R<L?}=!a^}0y&tDneUO^{=jlDX0*0(q0An3ZpRXs~aFWj?wc!@|JS
zoJ}8?kQEZIJ!~X}(Vq=O=WA*G<etkK*1WN3e@z>G=bnbgRr9M+u}{jp7ydMJN^<vU
z8*REm8S<<yCi!ysyt-_fBK15S#&Iq4Oq_vqqaqf#rB}lM37i1)g%&n6z5cj6HKXWp
zr;h82KDrgS%U_=1+gE9qzAg3XQVK|IImkvV0~c{%yDN6Z@(53<9w56F`59!DfVj&f
zA{jKZDuFHuxr|G-E@O6G7LMzx1?E@JDXU&Y$E}*0N^361T4w0bA&iZK_zlU8unP|#
z$;UYVwd$Vq*B^YkFeM97(bDysc!@yvV@4JpY6i}*op6?HwY<|z2_K`pntZ8OR(!AD
zrNx^-_2va7POIEZbah179#k-76p9WDU!vrtxfFcr2UMI&bDD%3^reQ;KMK)x%U^XO
zscl{Psv|9LCyKoutCNAc%qc&Ma^a$s5gU9ie{#6Iz9gH(=i5t{dScHG8Eb9QSa2b@
zo{jo&2E!NKU^_h*F=y_X*}?2({66=|&QF~TYAO0@cj|?)>)W@t){SwRelgUb%&^y1
zM;W@kz|uUoUabJ?0dbrrlPe>APntXLz&pJ5ZWI7}GEh1`;2^(^ytgu48%@k}`m_4R
zx8US1L-x+#p75_R@wMZVM}ykuYvioTTGW)v@utp6&FdCbVm5jv1($E4n`7P(vX8P^
zVZA#7-KlKgbTX}&!a_R%ta^0&^b~I$WKg~SIROeW8CO-de{#3jS6!TXFi85;P@Hrz
zD3>)2F0f1;VrK&%21hW;jd0Cjw4<mw8CV7UVXS`sw)0`|tmkMbu5>?npnIr&aVCT_
zW9a^Bg^fd&pImbNpxTP+{rooTc`NU48`F^mV8?f=97sYHnM7{LO)G6#omwpLj@zjk
z*`m5o3~<=GP<O*VmcrpnAG_a2N{tsh-f|k`i<yyGXGABaCFyG%>;|qAvDunf<-pg&
zIH~t>Us-XJV%rkrKOD99=3flubRj$V{UNE2PCJI@Qi7&wDXM|x@Dll=Tj)D@Y(u1P
z7_yCfQ%}|zKKprCcz*XtvG}TKViW44NE~ZF&3pW4f2!sm`cI`U`Bl!2_PqS3Dvok5
z=2eTiaWh#`Q&nhOeYk8Y2gu}DUKS%W-&K5bD>U`DQo92*Z9Jvl-A7zo%D^O5+z3<A
zbZxr1jz3UJH7r5k@GR}7Xwvu0Va8I?Z1teASZu_c|HVgndKPR!oZo+l5bV~?C&3wM
zcS{g1%h_fUL#vYy-qs4us(E#Y$?z+_>*TS2sjBs^v)SGJg_-$$y+3;FN@u#o{#rqd
z=-;Zemc);1)~-n;ZNYgD*QCx)qTS?(6>`Yxu0|T02j9{jA-iY!XBs6VtKgN(?M>3M
zXitp$#9|Y^aqefnpO5s_bc&VI`Mol8lb36szrH?8J9^Y{Sh=Zut;vy9EAFY*!eBw<
zUh1>Fup<1+##XO=O2huD7w?@yH~akK6(i-EANrw@1tl$;?SdE;AJIJyTU&yrti_SX
zqL2K}JyH4R*vHyPyly4H@@Qky6>b`Z!-~dp<=^<0ql8jCIzJ{n2`02PuA?k^A&hB?
zljJT{WGG{Bb%mft`m0YCNhgQcH?}Ga`o4KT7r9mpTO|G-ajjf)r<b9NJD^U_OV|bd
zIMdC?AJ;m0ml-XtGZF8}Md-?DEBEKdcw6^ppy?MF7!EU&=q;1{qeKi<pjux17~xi1
V^??kj$kLq2r$#fD{2!gn{tGu6WuyQA

diff --git a/extern/libpng/include/pngbar.png b/extern/libpng/include/pngbar.png
deleted file mode 100644
index 49798c8ed957b407692306792a73df4312f80cbb..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 2399
zcmV-l3840gP)<h;3K|Lk000e1NJLTq003A30018d0{{R3R2KTu00004XF*Lt006O%
z3;baP00001b5ch_0olnce*gdiyHHG2MF0Q*ud%PGtErit!ESMRrKhFdNl9>Uae~l{
z0Rja6`T3xspr4_iba{e!dVHCinSz3e@1>=%j($2G9;~mjBv2nTG{hSR28W4<;$UEa
zfq+#nVBJJS0RaHmC@AQFfQX5U(+mu00070t%A%vz78nt@y3y1S5N2m)Kc7E!n|s1o
zS3*LZ`|ImCIy_xnT}Vn#B_<}-6cj!`B>eC1D=aTfO-&XS7mt#WfPvpvG$H~507gef
za(0FG_V)er^K^NAv$WC-3=ME`<MOzf3JMF!%gqM}2pkm_0s;d800IC20TmAqQ&m}$
zl-e*cFfT7J>ynZ!EiHe1F4i6%tFFzXq(o3jLNqluBO@b<ijo~29n8+mJUv1g9T{I>
zVbTT$78e$QPf^Cm#xylL6B84MYEWEsVPscG4Gj%}gp7rShJJ*J1_uTQ1qZgcwgm+R
zTU=lS0|Z`PB(t=$0s#U60RaF30IsgC78d%fuB?oX+;MYqIXXKmD<L8^7p1I`Gcq+L
z9~!KzMU#}1>vVH6GZr>DJ8*F|pP|?3h={zu&lnR8iH(zuj*X0tj8%hK4-gJ}V^=2}
z6>oEP2?_mre}vT-7)}5HC?_Km6cv1ad;tIecYA?^h0qZY6Aum%b9;T@R8)kCkwQa5
zadmqS2M0SlJZ)}m(EtEcS6dMa3_n3bUt?)wWMf%cS%!(3`QP6|MM@eP`5+-7d3AOF
z|Nm+%D{E|VNkkrIXlz47LkkNGKtMq3?d<#K=S5UV_RGudo}K{#0%vG&=I7>ARK#Xx
zZ!<JA@vpCkjf^!&IBjluDk>^wXXe#HK_DO?>Sbn6Qdo$IQAs2u8X6iK7#qpU$!=|P
zH#j{eCMlYoeM(75KtVqc5c_+8WeN%km6n;gySbjFueP_g0|EoHwX*;K|7dG)!Bu-G
z000IGNkl<ZNXNC-{a4dg7zgm%Ds#$9aO%_!5vM|gK|v(Ehyz7o$gsR91A7@%tg}GH
zwKWa|Q79-#2MmNMGLQ`^NO|i30hx+!1_g#nR$;(u883gvZUS1+9rXu&&Pkh-_I%FG
zH}|<WpzZxsDro!s_jgt6jnxW3+i&oVwP|2r!0*Bv|5j_PA6ZyHzqU-E=XA1mTI>Ht
z*vcw)0ZfC}7KY%R=*angFf7GDQDX{kit>gDqYzS58b_&yP)Sh~f_vJw^;p^2y#yCM
zISs%G832=BMOOfjy#g<itZ8sjh%qAAW^Bv`*60mTj5P%F2ncxs9uL7=tJa71X0`2K
z0Fy^{M|5Pb+EOU@+MSv0n!aVTywC_UQP^}tC@~Q!V)zipp-xQjU?GoCv#<-!V>7m@
zt+jh(w*X#u^vDspeASlpa4&Rno;k@j!sy{`WCR+Uq@`vIjHM+IP*3zXu&|I&vvBhr
zt5-6<$<K?VzkYb!TlQ6k@NB?sS(^L&C?LcJbxBeV4P!bPxB&n$q*1yoOw7%S($HnS
z*7M-)+qaW{S-Kae)!%Tptav&c{nXvky?Qv11bdAzqy|N}f`*+93>;<(2f0#8w1lUp
z1?ZrY7`SR}R`W7r#`?tgl6cdPoX?M$DvQtWI;4E?_jQN%)H5pc$G$QI+vc!SEpCkx
z#+g9_7fww<Ob59J3^Re~!wel*92>>9<vl%HjU$dOFRnk@>KozuLwWI;j6+9TpA<P9
z^!O+Gv8tR#@ILK62><YWiw3doY0iqB7loixbLERs)q}vZn(CFBj4y*vlf@G*mx4&A
z#KUY9s5`U+a0(5K8Jrmxni<f*xjYVYjl<l5$<$mFw;W52u(PJ~Y?ErS>hcZ3t)y?l
zdFG(xs{LWrE<if(Vc~I42F4{cZ9@aP%LPv6r}8nqK*B}Wq^3BIi41HMZ9dI+=E0g7
z^F_8z^&!U!ZcA%+<m}Ld1loT%61KFZuCA_yf&H}p42&~(3}Bo-MYM#lsVRdE!RT5e
zjyKZJ*eLcdY-zH1X85z8H1de_f&$lwUz(Z{Gt=$uzsZzqW}e2MV_<)+-|UD53=I3#
z1ks;FbKo-yr|>9KT-raI@mim4p&N{FMfnYvkx$&R<(ms07RfJb`ikXw53l+@$=(}P
z?MpK-^c){YFoBt|a4?lG5TfY@J<<>?PQod%2Mgco&28>|0SA}+mYBOllOs`!S5By%
zPP)yMN8hY0FHucYC;n_6!ovRAX#_Va6gmb@(5FOo!%@D@y8%T(VK`nksAFI>hf954
z%;R4p&z*B}R#o1+ANee}?qI;Zm|;~&O?-uKytC6Dx4SG1Pcbm+Lj?nKq_BGl<cL6&
z0l_s1IIa`6GVq<;+E_=c`7M1i?-E&AIXQIfxDaGy0HG{kNLEo9G~3b;`fob$KNDAn
z#=meL|LNn{ylm@ycy*OSUS@~aqoIz7JO_uo2>H;X_Kt|nbMUG0>1pkOx7k6gb9<~7
zEJCZ>+w;OZR<y6^2+x~49dZqygKaNrbM_@`A<7c1j$E{mrQ&LXNj}6do<i42m_idG
zhHdGp(6!btt!~$jfdKNv^%F~Pf@{}6Kp=U2GALj!3cqPvwDEaD+=UP)KtA9=x+|;(
zEonGTVf=o+#6ZV{H8QY|V_Vy;()sXZo3KF}_YliH(H4`BJIT&qnMJ)MUN8#}B%?Gu
zJvX8U6{ChxV-}EBaA;naq7lI&E-X_NrX(pD*wNbVgWLrfSN4qv`{<FrU6J=?Ep_1A
z7U{j=!ag@6tWBQYiPMx=VW9K7(TD}3JoFoa0TVAD46^X@tXDVFAV7k3Bmj58T@o<g
z>w?IW&lmbl5aqEGH3-e+iMsSUx=|fB7lp(Cl}Z05;e)elg=25lhPU3OFC-`X4O~Pp
z(+u8SxX6@Nu-gU$cM%?iDf;}>eg@uPwZ7NbAfwc4%LKv$AESApwMAQTgR)Bj)d}7P
zwCAfKkJo5opoC@6Lg<3Mcwvcs4!^5<=}qW6{9V<j###+PoD95|`VaK6Ze=au@=X8$
z04#JxSad^gaCvfRXJ~W)F*!LmAV+d#XCP8<Wo&O|b08>gWp{KyaBpI7crIgaZ7IUp
RQSJZ$002ovPDHLkV1iCKFfIT9

diff --git a/extern/libpng/include/pngconf.h b/extern/libpng/include/pngconf.h
deleted file mode 100644
index bbb547f8eb..0000000000
--- a/extern/libpng/include/pngconf.h
+++ /dev/null
@@ -1,596 +0,0 @@
-
-/* pngconf.h - machine configurable file for libpng
- *
- * libpng version 1.5.10 - March 29, 2012
- *
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- */
-
-/* Any machine specific code is near the front of this file, so if you
- * are configuring libpng for a machine, you may want to read the section
- * starting here down to where it starts to typedef png_color, png_text,
- * and png_info.
- */
-
-#ifndef PNGCONF_H
-#define PNGCONF_H
-
-#ifndef PNG_BUILDING_SYMBOL_TABLE
-/* PNG_NO_LIMITS_H may be used to turn off the use of the standard C
- * definition file for  machine specific limits, this may impact the
- * correctness of the definitons below (see uses of INT_MAX).
- */
-#  ifndef PNG_NO_LIMITS_H
-#    include <limits.h>
-#  endif
-
-/* For the memory copy APIs (i.e. the standard definitions of these),
- * because this file defines png_memcpy and so on the base APIs must
- * be defined here.
- */
-#  ifdef BSD
-#    include <strings.h>
-#  else
-#    include <string.h>
-#  endif
-
-/* For png_FILE_p - this provides the standard definition of a
- * FILE
- */
-#  ifdef PNG_STDIO_SUPPORTED
-#    include <stdio.h>
-#  endif
-#endif
-
-/* This controls optimization of the reading of 16 and 32 bit values
- * from PNG files.  It can be set on a per-app-file basis - it
- * just changes whether a macro is used when the function is called.
- * The library builder sets the default; if read functions are not
- * built into the library the macro implementation is forced on.
- */
-#ifndef PNG_READ_INT_FUNCTIONS_SUPPORTED
-#  define PNG_USE_READ_MACROS
-#endif
-#if !defined(PNG_NO_USE_READ_MACROS) && !defined(PNG_USE_READ_MACROS)
-#  if PNG_DEFAULT_READ_MACROS
-#    define PNG_USE_READ_MACROS
-#  endif
-#endif
-
-/* COMPILER SPECIFIC OPTIONS.
- *
- * These options are provided so that a variety of difficult compilers
- * can be used.  Some are fixed at build time (e.g. PNG_API_RULE
- * below) but still have compiler specific implementations, others
- * may be changed on a per-file basis when compiling against libpng.
- */
-
-/* The PNGARG macro protects us against machines that don't have function
- * prototypes (ie K&R style headers).  If your compiler does not handle
- * function prototypes, define this macro and use the included ansi2knr.
- * I've always been able to use _NO_PROTO as the indicator, but you may
- * need to drag the empty declaration out in front of here, or change the
- * ifdef to suit your own needs.
- */
-#ifndef PNGARG
-
-#  ifdef OF /* zlib prototype munger */
-#    define PNGARG(arglist) OF(arglist)
-#  else
-
-#    ifdef _NO_PROTO
-#      define PNGARG(arglist) ()
-#    else
-#      define PNGARG(arglist) arglist
-#    endif /* _NO_PROTO */
-
-#  endif /* OF */
-
-#endif /* PNGARG */
-
-/* Function calling conventions.
- * =============================
- * Normally it is not necessary to specify to the compiler how to call
- * a function - it just does it - however on x86 systems derived from
- * Microsoft and Borland C compilers ('IBM PC', 'DOS', 'Windows' systems
- * and some others) there are multiple ways to call a function and the
- * default can be changed on the compiler command line.  For this reason
- * libpng specifies the calling convention of every exported function and
- * every function called via a user supplied function pointer.  This is
- * done in this file by defining the following macros:
- *
- * PNGAPI    Calling convention for exported functions.
- * PNGCBAPI  Calling convention for user provided (callback) functions.
- * PNGCAPI   Calling convention used by the ANSI-C library (required
- *           for longjmp callbacks and sometimes used internally to
- *           specify the calling convention for zlib).
- *
- * These macros should never be overridden.  If it is necessary to
- * change calling convention in a private build this can be done
- * by setting PNG_API_RULE (which defaults to 0) to one of the values
- * below to select the correct 'API' variants.
- *
- * PNG_API_RULE=0 Use PNGCAPI - the 'C' calling convention - throughout.
- *                This is correct in every known environment.
- * PNG_API_RULE=1 Use the operating system convention for PNGAPI and
- *                the 'C' calling convention (from PNGCAPI) for
- *                callbacks (PNGCBAPI).  This is no longer required
- *                in any known environment - if it has to be used
- *                please post an explanation of the problem to the
- *                libpng mailing list.
- *
- * These cases only differ if the operating system does not use the C
- * calling convention, at present this just means the above cases
- * (x86 DOS/Windows sytems) and, even then, this does not apply to
- * Cygwin running on those systems.
- *
- * Note that the value must be defined in pnglibconf.h so that what
- * the application uses to call the library matches the conventions
- * set when building the library.
- */
-
-/* Symbol export
- * =============
- * When building a shared library it is almost always necessary to tell
- * the compiler which symbols to export.  The png.h macro 'PNG_EXPORT'
- * is used to mark the symbols.  On some systems these symbols can be
- * extracted at link time and need no special processing by the compiler,
- * on other systems the symbols are flagged by the compiler and just
- * the declaration requires a special tag applied (unfortunately) in a
- * compiler dependent way.  Some systems can do either.
- *
- * A small number of older systems also require a symbol from a DLL to
- * be flagged to the program that calls it.  This is a problem because
- * we do not know in the header file included by application code that
- * the symbol will come from a shared library, as opposed to a statically
- * linked one.  For this reason the application must tell us by setting
- * the magic flag PNG_USE_DLL to turn on the special processing before
- * it includes png.h.
- *
- * Four additional macros are used to make this happen:
- *
- * PNG_IMPEXP The magic (if any) to cause a symbol to be exported from
- *            the build or imported if PNG_USE_DLL is set - compiler
- *            and system specific.
- *
- * PNG_EXPORT_TYPE(type) A macro that pre or appends PNG_IMPEXP to
- *                       'type', compiler specific.
- *
- * PNG_DLL_EXPORT Set to the magic to use during a libpng build to
- *                make a symbol exported from the DLL.  Not used in the
- *                public header files; see pngpriv.h for how it is used
- *                in the libpng build.
- *
- * PNG_DLL_IMPORT Set to the magic to force the libpng symbols to come
- *                from a DLL - used to define PNG_IMPEXP when
- *                PNG_USE_DLL is set.
- */
-
-/* System specific discovery.
- * ==========================
- * This code is used at build time to find PNG_IMPEXP, the API settings
- * and PNG_EXPORT_TYPE(), it may also set a macro to indicate the DLL
- * import processing is possible.  On Windows/x86 systems it also sets
- * compiler-specific macros to the values required to change the calling
- * conventions of the various functions.
- */
-#if ( defined(_Windows) || defined(_WINDOWS) || defined(WIN32) ||\
-      defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__) ) &&\
-    ( defined(_X86_) || defined(_X64_) || defined(_M_IX86) ||\
-      defined(_M_X64) || defined(_M_IA64) )
-  /* Windows system (DOS doesn't support DLLs) running on x86/x64.  Includes
-   * builds under Cygwin or MinGW.  Also includes Watcom builds but these need
-   * special treatment because they are not compatible with GCC or Visual C
-   * because of different calling conventions.
-   */
-#  if PNG_API_RULE == 2
-    /* If this line results in an error, either because __watcall is not
-     * understood or because of a redefine just below you cannot use *this*
-     * build of the library with the compiler you are using.  *This* build was
-     * build using Watcom and applications must also be built using Watcom!
-     */
-#    define PNGCAPI __watcall
-#  endif
-
-#  if defined(__GNUC__) || (defined (_MSC_VER) && (_MSC_VER >= 800))
-#    define PNGCAPI __cdecl
-#    if PNG_API_RULE == 1
-#      define PNGAPI __stdcall
-#    endif
-#  else
-    /* An older compiler, or one not detected (erroneously) above,
-     * if necessary override on the command line to get the correct
-     * variants for the compiler.
-     */
-#    ifndef PNGCAPI
-#      define PNGCAPI _cdecl
-#    endif
-#    if PNG_API_RULE == 1 && !defined(PNGAPI)
-#      define PNGAPI _stdcall
-#    endif
-#  endif /* compiler/api */
-  /* NOTE: PNGCBAPI always defaults to PNGCAPI. */
-
-#  if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
-   ERROR: PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed
-#  endif
-
-#  if (defined(_MSC_VER) && _MSC_VER < 800) ||\
-      (defined(__BORLANDC__) && __BORLANDC__ < 0x500)
-    /* older Borland and MSC
-     * compilers used '__export' and required this to be after
-     * the type.
-     */
-#    ifndef PNG_EXPORT_TYPE
-#      define PNG_EXPORT_TYPE(type) type PNG_IMPEXP
-#    endif
-#    define PNG_DLL_EXPORT __export
-#  else /* newer compiler */
-#    define PNG_DLL_EXPORT __declspec(dllexport)
-#    ifndef PNG_DLL_IMPORT
-#      define PNG_DLL_IMPORT __declspec(dllimport)
-#    endif
-#  endif /* compiler */
-
-#else /* !Windows/x86 */
-#  if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
-#    define PNGAPI _System
-#  else /* !Windows/x86 && !OS/2 */
-    /* Use the defaults, or define PNG*API on the command line (but
-     * this will have to be done for every compile!)
-     */
-#  endif /* other system, !OS/2 */
-#endif /* !Windows/x86 */
-
-/* Now do all the defaulting . */
-#ifndef PNGCAPI
-#  define PNGCAPI
-#endif
-#ifndef PNGCBAPI
-#  define PNGCBAPI PNGCAPI
-#endif
-#ifndef PNGAPI
-#  define PNGAPI PNGCAPI
-#endif
-
-/* PNG_IMPEXP may be set on the compilation system command line or (if not set)
- * then in an internal header file when building the library, otherwise (when
- * using the library) it is set here.
- */
-#ifndef PNG_IMPEXP
-#  if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT)
-     /* This forces use of a DLL, disallowing static linking */
-#    define PNG_IMPEXP PNG_DLL_IMPORT
-#  endif
-
-#  ifndef PNG_IMPEXP
-#    define PNG_IMPEXP
-#  endif
-#endif
-
-/* In 1.5.2 the definition of PNG_FUNCTION has been changed to always treat
- * 'attributes' as a storage class - the attributes go at the start of the
- * function definition, and attributes are always appended regardless of the
- * compiler.  This considerably simplifies these macros but may cause problems
- * if any compilers both need function attributes and fail to handle them as
- * a storage class (this is unlikely.)
- */
-#ifndef PNG_FUNCTION
-#  define PNG_FUNCTION(type, name, args, attributes) attributes type name args
-#endif
-
-#ifndef PNG_EXPORT_TYPE
-#  define PNG_EXPORT_TYPE(type) PNG_IMPEXP type
-#endif
-
-   /* The ordinal value is only relevant when preprocessing png.h for symbol
-    * table entries, so we discard it here.  See the .dfn files in the
-    * scripts directory.
-    */
-#ifndef PNG_EXPORTA
-
-#  define PNG_EXPORTA(ordinal, type, name, args, attributes)\
-      PNG_FUNCTION(PNG_EXPORT_TYPE(type),(PNGAPI name),PNGARG(args), \
-        extern attributes)
-#endif
-
-/* ANSI-C (C90) does not permit a macro to be invoked with an empty argument,
- * so make something non-empty to satisfy the requirement:
- */
-#define PNG_EMPTY /*empty list*/
-
-#define PNG_EXPORT(ordinal, type, name, args)\
-   PNG_EXPORTA(ordinal, type, name, args, PNG_EMPTY)
-
-/* Use PNG_REMOVED to comment out a removed interface. */
-#ifndef PNG_REMOVED
-#  define PNG_REMOVED(ordinal, type, name, args, attributes)
-#endif
-
-#ifndef PNG_CALLBACK
-#  define PNG_CALLBACK(type, name, args) type (PNGCBAPI name) PNGARG(args)
-#endif
-
-/* Support for compiler specific function attributes.  These are used
- * so that where compiler support is available incorrect use of API
- * functions in png.h will generate compiler warnings.
- *
- * Added at libpng-1.2.41.
- */
-
-#ifndef PNG_NO_PEDANTIC_WARNINGS
-#  ifndef PNG_PEDANTIC_WARNINGS_SUPPORTED
-#    define PNG_PEDANTIC_WARNINGS_SUPPORTED
-#  endif
-#endif
-
-#ifdef PNG_PEDANTIC_WARNINGS_SUPPORTED
-  /* Support for compiler specific function attributes.  These are used
-   * so that where compiler support is available incorrect use of API
-   * functions in png.h will generate compiler warnings.  Added at libpng
-   * version 1.2.41.
-   */
-#  if defined(__GNUC__)
-#    ifndef PNG_USE_RESULT
-#      define PNG_USE_RESULT __attribute__((__warn_unused_result__))
-#    endif
-#    ifndef PNG_NORETURN
-#      define PNG_NORETURN   __attribute__((__noreturn__))
-#    endif
-#    ifndef PNG_ALLOCATED
-#      define PNG_ALLOCATED  __attribute__((__malloc__))
-#    endif
-#    ifndef PNG_DEPRECATED
-#      define PNG_DEPRECATED __attribute__((__deprecated__))
-#    endif
-#    ifndef PNG_PRIVATE
-#      if 0 /* Doesn't work so we use deprecated instead*/
-#        define PNG_PRIVATE \
-          __attribute__((warning("This function is not exported by libpng.")))
-#      else
-#        define PNG_PRIVATE \
-          __attribute__((__deprecated__))
-#      endif
-#    endif
-#  endif /* __GNUC__ */
-
-#  if defined(_MSC_VER)  && (_MSC_VER >= 1300)
-#    ifndef PNG_USE_RESULT
-#      define PNG_USE_RESULT /* not supported */
-#    endif
-#    ifndef PNG_NORETURN
-#      define PNG_NORETURN __declspec(noreturn)
-#    endif
-#    ifndef PNG_ALLOCATED
-#      if (_MSC_VER >= 1400)
-#        define PNG_ALLOCATED __declspec(restrict)
-#      endif
-#    endif
-#    ifndef PNG_DEPRECATED
-#      define PNG_DEPRECATED __declspec(deprecated)
-#    endif
-#    ifndef PNG_PRIVATE
-#      define PNG_PRIVATE __declspec(deprecated)
-#    endif
-#  endif /* _MSC_VER */
-#endif /* PNG_PEDANTIC_WARNINGS */
-
-#ifndef PNG_DEPRECATED
-#  define PNG_DEPRECATED  /* Use of this function is deprecated */
-#endif
-#ifndef PNG_USE_RESULT
-#  define PNG_USE_RESULT  /* The result of this function must be checked */
-#endif
-#ifndef PNG_NORETURN
-#  define PNG_NORETURN    /* This function does not return */
-#endif
-#ifndef PNG_ALLOCATED
-#  define PNG_ALLOCATED   /* The result of the function is new memory */
-#endif
-#ifndef PNG_PRIVATE
-#  define PNG_PRIVATE     /* This is a private libpng function */
-#endif
-#ifndef PNG_FP_EXPORT     /* A floating point API. */
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-#     define PNG_FP_EXPORT(ordinal, type, name, args)\
-         PNG_EXPORT(ordinal, type, name, args)
-#  else                   /* No floating point APIs */
-#     define PNG_FP_EXPORT(ordinal, type, name, args)
-#  endif
-#endif
-#ifndef PNG_FIXED_EXPORT  /* A fixed point API. */
-#  ifdef PNG_FIXED_POINT_SUPPORTED
-#     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
-         PNG_EXPORT(ordinal, type, name, args)
-#  else                   /* No fixed point APIs */
-#     define PNG_FIXED_EXPORT(ordinal, type, name, args)
-#  endif
-#endif
-
-/* The following uses const char * instead of char * for error
- * and warning message functions, so some compilers won't complain.
- * If you do not want to use const, define PNG_NO_CONST here.
- *
- * This should not change how the APIs are called, so it can be done
- * on a per-file basis in the application.
- */
-#ifndef PNG_CONST
-#  ifndef PNG_NO_CONST
-#    define PNG_CONST const
-#  else
-#    define PNG_CONST
-#  endif
-#endif
-
-/* Some typedefs to get us started.  These should be safe on most of the
- * common platforms.  The typedefs should be at least as large as the
- * numbers suggest (a png_uint_32 must be at least 32 bits long), but they
- * don't have to be exactly that size.  Some compilers dislike passing
- * unsigned shorts as function parameters, so you may be better off using
- * unsigned int for png_uint_16.
- */
-
-#if defined(INT_MAX) && (INT_MAX > 0x7ffffffeL)
-typedef unsigned int png_uint_32;
-typedef int png_int_32;
-#else
-typedef unsigned long png_uint_32;
-typedef long png_int_32;
-#endif
-typedef unsigned short png_uint_16;
-typedef short png_int_16;
-typedef unsigned char png_byte;
-
-#ifdef PNG_NO_SIZE_T
-typedef unsigned int png_size_t;
-#else
-typedef size_t png_size_t;
-#endif
-#define png_sizeof(x) (sizeof (x))
-
-/* The following is needed for medium model support.  It cannot be in the
- * pngpriv.h header.  Needs modification for other compilers besides
- * MSC.  Model independent support declares all arrays and pointers to be
- * large using the far keyword.  The zlib version used must also support
- * model independent data.  As of version zlib 1.0.4, the necessary changes
- * have been made in zlib.  The USE_FAR_KEYWORD define triggers other
- * changes that are needed. (Tim Wegner)
- */
-
-/* Separate compiler dependencies (problem here is that zlib.h always
- * defines FAR. (SJT)
- */
-#ifdef __BORLANDC__
-#  if defined(__LARGE__) || defined(__HUGE__) || defined(__COMPACT__)
-#    define LDATA 1
-#  else
-#    define LDATA 0
-#  endif
-  /* GRR:  why is Cygwin in here?  Cygwin is not Borland C... */
-#  if !defined(__WIN32__) && !defined(__FLAT__) && !defined(__CYGWIN__)
-#    define PNG_MAX_MALLOC_64K /* only used in build */
-#    if (LDATA != 1)
-#      ifndef FAR
-#        define FAR __far
-#      endif
-#      define USE_FAR_KEYWORD
-#    endif   /* LDATA != 1 */
-         /* Possibly useful for moving data out of default segment.
-          * Uncomment it if you want. Could also define FARDATA as
-          * const if your compiler supports it. (SJT)
-#        define FARDATA FAR
-          */
-#  endif  /* __WIN32__, __FLAT__, __CYGWIN__ */
-#endif   /* __BORLANDC__ */
-
-
-/* Suggest testing for specific compiler first before testing for
- * FAR.  The Watcom compiler defines both __MEDIUM__ and M_I86MM,
- * making reliance oncertain keywords suspect. (SJT)
- */
-
-/* MSC Medium model */
-#ifdef FAR
-#  ifdef M_I86MM
-#    define USE_FAR_KEYWORD
-#    define FARDATA FAR
-#    include <dos.h>
-#  endif
-#endif
-
-/* SJT: default case */
-#ifndef FAR
-#  define FAR
-#endif
-
-/* At this point FAR is always defined */
-#ifndef FARDATA
-#  define FARDATA
-#endif
-
-/* Typedef for floating-point numbers that are converted
- * to fixed-point with a multiple of 100,000, e.g., gamma
- */
-typedef png_int_32 png_fixed_point;
-
-/* Add typedefs for pointers */
-typedef void                      FAR * png_voidp;
-typedef PNG_CONST void            FAR * png_const_voidp;
-typedef png_byte                  FAR * png_bytep;
-typedef PNG_CONST png_byte        FAR * png_const_bytep;
-typedef png_uint_32               FAR * png_uint_32p;
-typedef PNG_CONST png_uint_32     FAR * png_const_uint_32p;
-typedef png_int_32                FAR * png_int_32p;
-typedef PNG_CONST png_int_32      FAR * png_const_int_32p;
-typedef png_uint_16               FAR * png_uint_16p;
-typedef PNG_CONST png_uint_16     FAR * png_const_uint_16p;
-typedef png_int_16                FAR * png_int_16p;
-typedef PNG_CONST png_int_16      FAR * png_const_int_16p;
-typedef char                      FAR * png_charp;
-typedef PNG_CONST char            FAR * png_const_charp;
-typedef png_fixed_point           FAR * png_fixed_point_p;
-typedef PNG_CONST png_fixed_point FAR * png_const_fixed_point_p;
-typedef png_size_t                FAR * png_size_tp;
-typedef PNG_CONST png_size_t      FAR * png_const_size_tp;
-
-#ifdef PNG_STDIO_SUPPORTED
-typedef FILE            * png_FILE_p;
-#endif
-
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-typedef double           FAR * png_doublep;
-typedef PNG_CONST double FAR * png_const_doublep;
-#endif
-
-/* Pointers to pointers; i.e. arrays */
-typedef png_byte        FAR * FAR * png_bytepp;
-typedef png_uint_32     FAR * FAR * png_uint_32pp;
-typedef png_int_32      FAR * FAR * png_int_32pp;
-typedef png_uint_16     FAR * FAR * png_uint_16pp;
-typedef png_int_16      FAR * FAR * png_int_16pp;
-typedef PNG_CONST char  FAR * FAR * png_const_charpp;
-typedef char            FAR * FAR * png_charpp;
-typedef png_fixed_point FAR * FAR * png_fixed_point_pp;
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-typedef double          FAR * FAR * png_doublepp;
-#endif
-
-/* Pointers to pointers to pointers; i.e., pointer to array */
-typedef char            FAR * FAR * FAR * png_charppp;
-
-/* png_alloc_size_t is guaranteed to be no smaller than png_size_t,
- * and no smaller than png_uint_32.  Casts from png_size_t or png_uint_32
- * to png_alloc_size_t are not necessary; in fact, it is recommended
- * not to use them at all so that the compiler can complain when something
- * turns out to be problematic.
- * Casts in the other direction (from png_alloc_size_t to png_size_t or
- * png_uint_32) should be explicitly applied; however, we do not expect
- * to encounter practical situations that require such conversions.
- */
-#if defined(__TURBOC__) && !defined(__FLAT__)
-   typedef unsigned long png_alloc_size_t;
-#else
-#  if defined(_MSC_VER) && defined(MAXSEG_64K)
-     typedef unsigned long    png_alloc_size_t;
-#  else
-     /* This is an attempt to detect an old Windows system where (int) is
-      * actually 16 bits, in that case png_malloc must have an argument with a
-      * bigger size to accomodate the requirements of the library.
-      */
-#    if (defined(_Windows) || defined(_WINDOWS) || defined(_WINDOWS_)) && \
-        (!defined(INT_MAX) || INT_MAX <= 0x7ffffffeL)
-       typedef DWORD         png_alloc_size_t;
-#    else
-       typedef png_size_t    png_alloc_size_t;
-#    endif
-#  endif
-#endif
-
-#endif /* PNGCONF_H */
diff --git a/extern/libpng/include/pngdebug.h b/extern/libpng/include/pngdebug.h
deleted file mode 100644
index 16f81fdd14..0000000000
--- a/extern/libpng/include/pngdebug.h
+++ /dev/null
@@ -1,157 +0,0 @@
-
-/* pngdebug.h - Debugging macros for libpng, also used in pngtest.c
- *
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * Last changed in libpng 1.5.0 [January 6, 2011]
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-/* Define PNG_DEBUG at compile time for debugging information.  Higher
- * numbers for PNG_DEBUG mean more debugging information.  This has
- * only been added since version 0.95 so it is not implemented throughout
- * libpng yet, but more support will be added as needed.
- *
- * png_debug[1-2]?(level, message ,arg{0-2})
- *   Expands to a statement (either a simple expression or a compound
- *   do..while(0) statement) that outputs a message with parameter
- *   substitution if PNG_DEBUG is defined to 2 or more.  If PNG_DEBUG
- *   is undefined, 0 or 1 every png_debug expands to a simple expression
- *   (actually ((void)0)).
- *
- *   level: level of detail of message, starting at 0.  A level 'n'
- *          message is preceded by 'n' tab characters (not implemented
- *          on Microsoft compilers unless PNG_DEBUG_FILE is also
- *          defined, to allow debug DLL compilation with no standard IO).
- *   message: a printf(3) style text string.  A trailing '\n' is added
- *            to the message.
- *   arg: 0 to 2 arguments for printf(3) style substitution in message.
- */
-#ifndef PNGDEBUG_H
-#define PNGDEBUG_H
-/* These settings control the formatting of messages in png.c and pngerror.c */
-/* Moved to pngdebug.h at 1.5.0 */
-#  ifndef PNG_LITERAL_SHARP
-#    define PNG_LITERAL_SHARP 0x23
-#  endif
-#  ifndef PNG_LITERAL_LEFT_SQUARE_BRACKET
-#    define PNG_LITERAL_LEFT_SQUARE_BRACKET 0x5b
-#  endif
-#  ifndef PNG_LITERAL_RIGHT_SQUARE_BRACKET
-#    define PNG_LITERAL_RIGHT_SQUARE_BRACKET 0x5d
-#  endif
-#  ifndef PNG_STRING_NEWLINE
-#    define PNG_STRING_NEWLINE "\n"
-#  endif
-
-#ifdef PNG_DEBUG
-#  if (PNG_DEBUG > 0)
-#    if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)
-#      include <crtdbg.h>
-#      if (PNG_DEBUG > 1)
-#        ifndef _DEBUG
-#          define _DEBUG
-#        endif
-#        ifndef png_debug
-#          define png_debug(l,m)  _RPT0(_CRT_WARN,m PNG_STRING_NEWLINE)
-#        endif
-#        ifndef png_debug1
-#          define png_debug1(l,m,p1)  _RPT1(_CRT_WARN,m PNG_STRING_NEWLINE,p1)
-#        endif
-#        ifndef png_debug2
-#          define png_debug2(l,m,p1,p2) \
-             _RPT2(_CRT_WARN,m PNG_STRING_NEWLINE,p1,p2)
-#        endif
-#      endif
-#    else /* PNG_DEBUG_FILE || !_MSC_VER */
-#      ifndef PNG_STDIO_SUPPORTED
-#        include <stdio.h> /* not included yet */
-#      endif
-#      ifndef PNG_DEBUG_FILE
-#        define PNG_DEBUG_FILE stderr
-#      endif /* PNG_DEBUG_FILE */
-
-#      if (PNG_DEBUG > 1)
-/* Note: ["%s"m PNG_STRING_NEWLINE] probably does not work on
- * non-ISO compilers
- */
-#        ifdef __STDC__
-#          ifndef png_debug
-#            define png_debug(l,m) \
-       do { \
-       int num_tabs=l; \
-       fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
-         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":"")))); \
-       } while (0)
-#          endif
-#          ifndef png_debug1
-#            define png_debug1(l,m,p1) \
-       do { \
-       int num_tabs=l; \
-       fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
-         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1); \
-       } while (0)
-#          endif
-#          ifndef png_debug2
-#            define png_debug2(l,m,p1,p2) \
-       do { \
-       int num_tabs=l; \
-       fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
-         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1,p2); \
-       } while (0)
-#          endif
-#        else /* __STDC __ */
-#          ifndef png_debug
-#            define png_debug(l,m) \
-       do { \
-       int num_tabs=l; \
-       char format[256]; \
-       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
-         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
-         m,PNG_STRING_NEWLINE); \
-       fprintf(PNG_DEBUG_FILE,format); \
-       } while (0)
-#          endif
-#          ifndef png_debug1
-#            define png_debug1(l,m,p1) \
-       do { \
-       int num_tabs=l; \
-       char format[256]; \
-       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
-         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
-         m,PNG_STRING_NEWLINE); \
-       fprintf(PNG_DEBUG_FILE,format,p1); \
-       } while (0)
-#          endif
-#          ifndef png_debug2
-#            define png_debug2(l,m,p1,p2) \
-       do { \
-       int num_tabs=l; \
-       char format[256]; \
-       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
-         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
-         m,PNG_STRING_NEWLINE); \
-       fprintf(PNG_DEBUG_FILE,format,p1,p2); \
-       } while (0)
-#          endif
-#        endif /* __STDC __ */
-#      endif /* (PNG_DEBUG > 1) */
-
-#    endif /* _MSC_VER */
-#  endif /* (PNG_DEBUG > 0) */
-#endif /* PNG_DEBUG */
-#ifndef png_debug
-#  define png_debug(l, m) ((void)0)
-#endif
-#ifndef png_debug1
-#  define png_debug1(l, m, p1) ((void)0)
-#endif
-#ifndef png_debug2
-#  define png_debug2(l, m, p1, p2) ((void)0)
-#endif
-#endif /* PNGDEBUG_H */
diff --git a/extern/libpng/include/pngerror.c b/extern/libpng/include/pngerror.c
deleted file mode 100644
index 95002f84f7..0000000000
--- a/extern/libpng/include/pngerror.c
+++ /dev/null
@@ -1,685 +0,0 @@
-
-/* pngerror.c - stub functions for i/o and memory allocation
- *
- * Last changed in libpng 1.5.8 [February 1, 2011]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * This file provides a location for all error handling.  Users who
- * need special error handling are expected to write replacement functions
- * and use png_set_error_fn() to use those functions.  See the instructions
- * at each function.
- */
-
-#include "pngpriv.h"
-
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-
-static PNG_FUNCTION(void, png_default_error,PNGARG((png_structp png_ptr,
-    png_const_charp error_message)),PNG_NORETURN);
-
-#ifdef PNG_WARNINGS_SUPPORTED
-static void /* PRIVATE */
-png_default_warning PNGARG((png_structp png_ptr,
-   png_const_charp warning_message));
-#endif /* PNG_WARNINGS_SUPPORTED */
-
-/* This function is called whenever there is a fatal error.  This function
- * should not be changed.  If there is a need to handle errors differently,
- * you should supply a replacement error function and use png_set_error_fn()
- * to replace the error function at run-time.
- */
-#ifdef PNG_ERROR_TEXT_SUPPORTED
-PNG_FUNCTION(void,PNGAPI
-png_error,(png_structp png_ptr, png_const_charp error_message),PNG_NORETURN)
-{
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
-   char msg[16];
-   if (png_ptr != NULL)
-   {
-      if (png_ptr->flags&
-         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
-      {
-         if (*error_message == PNG_LITERAL_SHARP)
-         {
-            /* Strip "#nnnn " from beginning of error message. */
-            int offset;
-            for (offset = 1; offset<15; offset++)
-               if (error_message[offset] == ' ')
-                  break;
-
-            if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
-            {
-               int i;
-               for (i = 0; i < offset - 1; i++)
-                  msg[i] = error_message[i + 1];
-               msg[i - 1] = '\0';
-               error_message = msg;
-            }
-
-            else
-               error_message += offset;
-      }
-
-      else
-      {
-         if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
-         {
-            msg[0] = '0';
-            msg[1] = '\0';
-            error_message = msg;
-         }
-       }
-     }
-   }
-#endif
-   if (png_ptr != NULL && png_ptr->error_fn != NULL)
-      (*(png_ptr->error_fn))(png_ptr, error_message);
-
-   /* If the custom handler doesn't exist, or if it returns,
-      use the default handler, which will not return. */
-   png_default_error(png_ptr, error_message);
-}
-#else
-PNG_FUNCTION(void,PNGAPI
-png_err,(png_structp png_ptr),PNG_NORETURN)
-{
-   /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed
-    * erroneously as '\0', instead of the empty string "".  This was
-    * apparently an error, introduced in libpng-1.2.20, and png_default_error
-    * will crash in this case.
-    */
-   if (png_ptr != NULL && png_ptr->error_fn != NULL)
-      (*(png_ptr->error_fn))(png_ptr, "");
-
-   /* If the custom handler doesn't exist, or if it returns,
-      use the default handler, which will not return. */
-   png_default_error(png_ptr, "");
-}
-#endif /* PNG_ERROR_TEXT_SUPPORTED */
-
-/* Utility to safely appends strings to a buffer.  This never errors out so
- * error checking is not required in the caller.
- */
-size_t
-png_safecat(png_charp buffer, size_t bufsize, size_t pos,
-   png_const_charp string)
-{
-   if (buffer != NULL && pos < bufsize)
-   {
-      if (string != NULL)
-         while (*string != '\0' && pos < bufsize-1)
-           buffer[pos++] = *string++;
-
-      buffer[pos] = '\0';
-   }
-
-   return pos;
-}
-
-#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
-/* Utility to dump an unsigned value into a buffer, given a start pointer and
- * and end pointer (which should point just *beyond* the end of the buffer!)
- * Returns the pointer to the start of the formatted string.
- */
-png_charp
-png_format_number(png_const_charp start, png_charp end, int format,
-   png_alloc_size_t number)
-{
-   int count = 0;    /* number of digits output */
-   int mincount = 1; /* minimum number required */
-   int output = 0;   /* digit output (for the fixed point format) */
-
-   *--end = '\0';
-
-   /* This is written so that the loop always runs at least once, even with
-    * number zero.
-    */
-   while (end > start && (number != 0 || count < mincount))
-   {
-
-      static const char digits[] = "0123456789ABCDEF";
-
-      switch (format)
-      {
-         case PNG_NUMBER_FORMAT_fixed:
-            /* Needs five digits (the fraction) */
-            mincount = 5;
-            if (output || number % 10 != 0)
-            {
-               *--end = digits[number % 10];
-               output = 1;
-            }
-            number /= 10;
-            break;
-
-         case PNG_NUMBER_FORMAT_02u:
-            /* Expects at least 2 digits. */
-            mincount = 2;
-            /* fall through */
-
-         case PNG_NUMBER_FORMAT_u:
-            *--end = digits[number % 10];
-            number /= 10;
-            break;
-
-         case PNG_NUMBER_FORMAT_02x:
-            /* This format expects at least two digits */
-            mincount = 2;
-            /* fall through */
-
-         case PNG_NUMBER_FORMAT_x:
-            *--end = digits[number & 0xf];
-            number >>= 4;
-            break;
-
-         default: /* an error */
-            number = 0;
-            break;
-      }
-
-      /* Keep track of the number of digits added */
-      ++count;
-
-      /* Float a fixed number here: */
-      if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start)
-      {
-         /* End of the fraction, but maybe nothing was output?  In that case
-          * drop the decimal point.  If the number is a true zero handle that
-          * here.
-          */
-         if (output)
-            *--end = '.';
-         else if (number == 0) /* and !output */
-            *--end = '0';
-      }
-   }
-
-   return end;
-}
-#endif
-
-#ifdef PNG_WARNINGS_SUPPORTED
-/* This function is called whenever there is a non-fatal error.  This function
- * should not be changed.  If there is a need to handle warnings differently,
- * you should supply a replacement warning function and use
- * png_set_error_fn() to replace the warning function at run-time.
- */
-void PNGAPI
-png_warning(png_structp png_ptr, png_const_charp warning_message)
-{
-   int offset = 0;
-   if (png_ptr != NULL)
-   {
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
-   if (png_ptr->flags&
-       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
-#endif
-      {
-         if (*warning_message == PNG_LITERAL_SHARP)
-         {
-            for (offset = 1; offset < 15; offset++)
-               if (warning_message[offset] == ' ')
-                  break;
-         }
-      }
-   }
-   if (png_ptr != NULL && png_ptr->warning_fn != NULL)
-      (*(png_ptr->warning_fn))(png_ptr, warning_message + offset);
-   else
-      png_default_warning(png_ptr, warning_message + offset);
-}
-
-/* These functions support 'formatted' warning messages with up to
- * PNG_WARNING_PARAMETER_COUNT parameters.  In the format string the parameter
- * is introduced by @<number>, where 'number' starts at 1.  This follows the
- * standard established by X/Open for internationalizable error messages.
- */
-void
-png_warning_parameter(png_warning_parameters p, int number,
-   png_const_charp string)
-{
-   if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT)
-      (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string);
-}
-
-void
-png_warning_parameter_unsigned(png_warning_parameters p, int number, int format,
-   png_alloc_size_t value)
-{
-   char buffer[PNG_NUMBER_BUFFER_SIZE];
-   png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value));
-}
-
-void
-png_warning_parameter_signed(png_warning_parameters p, int number, int format,
-   png_int_32 value)
-{
-   png_alloc_size_t u;
-   png_charp str;
-   char buffer[PNG_NUMBER_BUFFER_SIZE];
-
-   /* Avoid overflow by doing the negate in a png_alloc_size_t: */
-   u = (png_alloc_size_t)value;
-   if (value < 0)
-      u = ~u + 1;
-
-   str = PNG_FORMAT_NUMBER(buffer, format, u);
-
-   if (value < 0 && str > buffer)
-      *--str = '-';
-
-   png_warning_parameter(p, number, str);
-}
-
-void
-png_formatted_warning(png_structp png_ptr, png_warning_parameters p,
-   png_const_charp message)
-{
-   /* The internal buffer is just 192 bytes - enough for all our messages,
-    * overflow doesn't happen because this code checks!  If someone figures
-    * out how to send us a message longer than 192 bytes, all that will
-    * happen is that the message will be truncated appropriately.
-    */
-   size_t i = 0; /* Index in the msg[] buffer: */
-   char msg[192];
-
-   /* Each iteration through the following loop writes at most one character
-    * to msg[i++] then returns here to validate that there is still space for
-    * the trailing '\0'.  It may (in the case of a parameter) read more than
-    * one character from message[]; it must check for '\0' and continue to the
-    * test if it finds the end of string.
-    */
-   while (i<(sizeof msg)-1 && *message != '\0')
-   {
-      /* '@' at end of string is now just printed (previously it was skipped);
-       * it is an error in the calling code to terminate the string with @.
-       */
-      if (p != NULL && *message == '@' && message[1] != '\0')
-      {
-         int parameter_char = *++message; /* Consume the '@' */
-         static const char valid_parameters[] = "123456789";
-         int parameter = 0;
-
-         /* Search for the parameter digit, the index in the string is the
-          * parameter to use.
-          */
-         while (valid_parameters[parameter] != parameter_char &&
-            valid_parameters[parameter] != '\0')
-            ++parameter;
-
-         /* If the parameter digit is out of range it will just get printed. */
-         if (parameter < PNG_WARNING_PARAMETER_COUNT)
-         {
-            /* Append this parameter */
-            png_const_charp parm = p[parameter];
-            png_const_charp pend = p[parameter] + (sizeof p[parameter]);
-
-            /* No need to copy the trailing '\0' here, but there is no guarantee
-             * that parm[] has been initialized, so there is no guarantee of a
-             * trailing '\0':
-             */
-            while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend)
-               msg[i++] = *parm++;
-
-            /* Consume the parameter digit too: */
-            ++message;
-            continue;
-         }
-
-         /* else not a parameter and there is a character after the @ sign; just
-          * copy that.  This is known not to be '\0' because of the test above.
-          */
-      }
-
-      /* At this point *message can't be '\0', even in the bad parameter case
-       * above where there is a lone '@' at the end of the message string.
-       */
-      msg[i++] = *message++;
-   }
-
-   /* i is always less than (sizeof msg), so: */
-   msg[i] = '\0';
-
-   /* And this is the formatted message, it may be larger than
-    * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these are
-    * not (currently) formatted.
-    */
-   png_warning(png_ptr, msg);
-}
-#endif /* PNG_WARNINGS_SUPPORTED */
-
-#ifdef PNG_BENIGN_ERRORS_SUPPORTED
-void PNGAPI
-png_benign_error(png_structp png_ptr, png_const_charp error_message)
-{
-  if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
-     png_warning(png_ptr, error_message);
-  else
-     png_error(png_ptr, error_message);
-}
-#endif
-
-/* These utilities are used internally to build an error message that relates
- * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
- * this is used to prefix the message.  The message is limited in length
- * to 63 bytes, the name characters are output as hex digits wrapped in []
- * if the character is invalid.
- */
-#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
-static PNG_CONST char png_digit[16] = {
-   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
-   'A', 'B', 'C', 'D', 'E', 'F'
-};
-
-#define PNG_MAX_ERROR_TEXT 64
-#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
-static void /* PRIVATE */
-png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
-    error_message)
-{
-   png_uint_32 chunk_name = png_ptr->chunk_name;
-   int iout = 0, ishift = 24;
-
-   while (ishift >= 0)
-   {
-      int c = (int)(chunk_name >> ishift) & 0xff;
-
-      ishift -= 8;
-      if (isnonalpha(c))
-      {
-         buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
-         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
-         buffer[iout++] = png_digit[c & 0x0f];
-         buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET;
-      }
-
-      else
-      {
-         buffer[iout++] = (char)c;
-      }
-   }
-
-   if (error_message == NULL)
-      buffer[iout] = '\0';
-
-   else
-   {
-      int iin = 0;
-
-      buffer[iout++] = ':';
-      buffer[iout++] = ' ';
-
-      while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
-         buffer[iout++] = error_message[iin++];
-
-      /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
-      buffer[iout] = '\0';
-   }
-}
-#endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */
-
-#if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
-PNG_FUNCTION(void,PNGAPI
-png_chunk_error,(png_structp png_ptr, png_const_charp error_message),
-   PNG_NORETURN)
-{
-   char msg[18+PNG_MAX_ERROR_TEXT];
-   if (png_ptr == NULL)
-      png_error(png_ptr, error_message);
-
-   else
-   {
-      png_format_buffer(png_ptr, msg, error_message);
-      png_error(png_ptr, msg);
-   }
-}
-#endif /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */
-
-#ifdef PNG_WARNINGS_SUPPORTED
-void PNGAPI
-png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)
-{
-   char msg[18+PNG_MAX_ERROR_TEXT];
-   if (png_ptr == NULL)
-      png_warning(png_ptr, warning_message);
-
-   else
-   {
-      png_format_buffer(png_ptr, msg, warning_message);
-      png_warning(png_ptr, msg);
-   }
-}
-#endif /* PNG_WARNINGS_SUPPORTED */
-
-#ifdef PNG_READ_SUPPORTED
-#ifdef PNG_BENIGN_ERRORS_SUPPORTED
-void PNGAPI
-png_chunk_benign_error(png_structp png_ptr, png_const_charp error_message)
-{
-   if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
-      png_chunk_warning(png_ptr, error_message);
-
-   else
-      png_chunk_error(png_ptr, error_message);
-}
-#endif
-#endif /* PNG_READ_SUPPORTED */
-
-#ifdef PNG_ERROR_TEXT_SUPPORTED
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-PNG_FUNCTION(void,
-png_fixed_error,(png_structp png_ptr, png_const_charp name),PNG_NORETURN)
-{
-#  define fixed_message "fixed point overflow in "
-#  define fixed_message_ln ((sizeof fixed_message)-1)
-   int  iin;
-   char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
-   png_memcpy(msg, fixed_message, fixed_message_ln);
-   iin = 0;
-   if (name != NULL) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
-   {
-      msg[fixed_message_ln + iin] = name[iin];
-      ++iin;
-   }
-   msg[fixed_message_ln + iin] = 0;
-   png_error(png_ptr, msg);
-}
-#endif
-#endif
-
-#ifdef PNG_SETJMP_SUPPORTED
-/* This API only exists if ANSI-C style error handling is used,
- * otherwise it is necessary for png_default_error to be overridden.
- */
-jmp_buf* PNGAPI
-png_set_longjmp_fn(png_structp png_ptr, png_longjmp_ptr longjmp_fn,
-    size_t jmp_buf_size)
-{
-   if (png_ptr == NULL || jmp_buf_size != png_sizeof(jmp_buf))
-      return NULL;
-
-   png_ptr->longjmp_fn = longjmp_fn;
-   return &png_ptr->longjmp_buffer;
-}
-#endif
-
-/* This is the default error handling function.  Note that replacements for
- * this function MUST NOT RETURN, or the program will likely crash.  This
- * function is used by default, or if the program supplies NULL for the
- * error function pointer in png_set_error_fn().
- */
-static PNG_FUNCTION(void /* PRIVATE */,
-png_default_error,(png_structp png_ptr, png_const_charp error_message),
-   PNG_NORETURN)
-{
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
-   /* Check on NULL only added in 1.5.4 */
-   if (error_message != NULL && *error_message == PNG_LITERAL_SHARP)
-   {
-      /* Strip "#nnnn " from beginning of error message. */
-      int offset;
-      char error_number[16];
-      for (offset = 0; offset<15; offset++)
-      {
-         error_number[offset] = error_message[offset + 1];
-         if (error_message[offset] == ' ')
-            break;
-      }
-
-      if ((offset > 1) && (offset < 15))
-      {
-         error_number[offset - 1] = '\0';
-         fprintf(stderr, "libpng error no. %s: %s",
-             error_number, error_message + offset + 1);
-         fprintf(stderr, PNG_STRING_NEWLINE);
-      }
-
-      else
-      {
-         fprintf(stderr, "libpng error: %s, offset=%d",
-             error_message, offset);
-         fprintf(stderr, PNG_STRING_NEWLINE);
-      }
-   }
-   else
-#endif
-   {
-      fprintf(stderr, "libpng error: %s", error_message ? error_message :
-         "undefined");
-      fprintf(stderr, PNG_STRING_NEWLINE);
-   }
-#else
-   PNG_UNUSED(error_message) /* Make compiler happy */
-#endif
-   png_longjmp(png_ptr, 1);
-}
-
-PNG_FUNCTION(void,PNGAPI
-png_longjmp,(png_structp png_ptr, int val),PNG_NORETURN)
-{
-#ifdef PNG_SETJMP_SUPPORTED
-   if (png_ptr && png_ptr->longjmp_fn)
-   {
-#  ifdef USE_FAR_KEYWORD
-      {
-         jmp_buf tmp_jmpbuf;
-         png_memcpy(tmp_jmpbuf, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
-         png_ptr->longjmp_fn(tmp_jmpbuf, val);
-      }
-
-#  else
-   png_ptr->longjmp_fn(png_ptr->longjmp_buffer, val);
-#  endif
-   }
-#endif
-   /* Here if not setjmp support or if png_ptr is null. */
-   PNG_ABORT();
-}
-
-#ifdef PNG_WARNINGS_SUPPORTED
-/* This function is called when there is a warning, but the library thinks
- * it can continue anyway.  Replacement functions don't have to do anything
- * here if you don't want them to.  In the default configuration, png_ptr is
- * not used, but it is passed in case it may be useful.
- */
-static void /* PRIVATE */
-png_default_warning(png_structp png_ptr, png_const_charp warning_message)
-{
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-#  ifdef PNG_ERROR_NUMBERS_SUPPORTED
-   if (*warning_message == PNG_LITERAL_SHARP)
-   {
-      int offset;
-      char warning_number[16];
-      for (offset = 0; offset < 15; offset++)
-      {
-         warning_number[offset] = warning_message[offset + 1];
-         if (warning_message[offset] == ' ')
-            break;
-      }
-
-      if ((offset > 1) && (offset < 15))
-      {
-         warning_number[offset + 1] = '\0';
-         fprintf(stderr, "libpng warning no. %s: %s",
-             warning_number, warning_message + offset);
-         fprintf(stderr, PNG_STRING_NEWLINE);
-      }
-
-      else
-      {
-         fprintf(stderr, "libpng warning: %s",
-             warning_message);
-         fprintf(stderr, PNG_STRING_NEWLINE);
-      }
-   }
-   else
-#  endif
-
-   {
-      fprintf(stderr, "libpng warning: %s", warning_message);
-      fprintf(stderr, PNG_STRING_NEWLINE);
-   }
-#else
-   PNG_UNUSED(warning_message) /* Make compiler happy */
-#endif
-   PNG_UNUSED(png_ptr) /* Make compiler happy */
-}
-#endif /* PNG_WARNINGS_SUPPORTED */
-
-/* This function is called when the application wants to use another method
- * of handling errors and warnings.  Note that the error function MUST NOT
- * return to the calling routine or serious problems will occur.  The return
- * method used in the default routine calls longjmp(png_ptr->longjmp_buffer, 1)
- */
-void PNGAPI
-png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
-    png_error_ptr error_fn, png_error_ptr warning_fn)
-{
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->error_ptr = error_ptr;
-   png_ptr->error_fn = error_fn;
-#ifdef PNG_WARNINGS_SUPPORTED
-   png_ptr->warning_fn = warning_fn;
-#else
-   PNG_UNUSED(warning_fn)
-#endif
-}
-
-
-/* This function returns a pointer to the error_ptr associated with the user
- * functions.  The application should free any memory associated with this
- * pointer before png_write_destroy and png_read_destroy are called.
- */
-png_voidp PNGAPI
-png_get_error_ptr(png_const_structp png_ptr)
-{
-   if (png_ptr == NULL)
-      return NULL;
-
-   return ((png_voidp)png_ptr->error_ptr);
-}
-
-
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
-void PNGAPI
-png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
-{
-   if (png_ptr != NULL)
-   {
-      png_ptr->flags &=
-         ((~(PNG_FLAG_STRIP_ERROR_NUMBERS |
-         PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
-   }
-}
-#endif
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/extern/libpng/include/pngget.c b/extern/libpng/include/pngget.c
deleted file mode 100644
index 43400cda7e..0000000000
--- a/extern/libpng/include/pngget.c
+++ /dev/null
@@ -1,1124 +0,0 @@
-
-/* pngget.c - retrieval of values from info struct
- *
- * Last changed in libpng 1.5.7 [December 15, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- */
-
-#include "pngpriv.h"
-
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-
-png_uint_32 PNGAPI
-png_get_valid(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_uint_32 flag)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return(info_ptr->valid & flag);
-
-   return(0);
-}
-
-png_size_t PNGAPI
-png_get_rowbytes(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return(info_ptr->rowbytes);
-
-   return(0);
-}
-
-#ifdef PNG_INFO_IMAGE_SUPPORTED
-png_bytepp PNGAPI
-png_get_rows(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return(info_ptr->row_pointers);
-
-   return(0);
-}
-#endif
-
-#ifdef PNG_EASY_ACCESS_SUPPORTED
-/* Easy access to info, added in libpng-0.99 */
-png_uint_32 PNGAPI
-png_get_image_width(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return info_ptr->width;
-
-   return (0);
-}
-
-png_uint_32 PNGAPI
-png_get_image_height(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return info_ptr->height;
-
-   return (0);
-}
-
-png_byte PNGAPI
-png_get_bit_depth(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return info_ptr->bit_depth;
-
-   return (0);
-}
-
-png_byte PNGAPI
-png_get_color_type(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return info_ptr->color_type;
-
-   return (0);
-}
-
-png_byte PNGAPI
-png_get_filter_type(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return info_ptr->filter_type;
-
-   return (0);
-}
-
-png_byte PNGAPI
-png_get_interlace_type(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return info_ptr->interlace_type;
-
-   return (0);
-}
-
-png_byte PNGAPI
-png_get_compression_type(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return info_ptr->compression_type;
-
-   return (0);
-}
-
-png_uint_32 PNGAPI
-png_get_x_pixels_per_meter(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-#ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
-      {
-         png_debug1(1, "in %s retrieval function",
-             "png_get_x_pixels_per_meter");
-
-         if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
-            return (info_ptr->x_pixels_per_unit);
-      }
-#endif
-
-   return (0);
-}
-
-png_uint_32 PNGAPI
-png_get_y_pixels_per_meter(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-#ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
-   {
-      png_debug1(1, "in %s retrieval function",
-          "png_get_y_pixels_per_meter");
-
-      if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
-         return (info_ptr->y_pixels_per_unit);
-   }
-#endif
-
-   return (0);
-}
-
-png_uint_32 PNGAPI
-png_get_pixels_per_meter(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-#ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
-   {
-      png_debug1(1, "in %s retrieval function", "png_get_pixels_per_meter");
-
-      if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER &&
-          info_ptr->x_pixels_per_unit == info_ptr->y_pixels_per_unit)
-         return (info_ptr->x_pixels_per_unit);
-   }
-#endif
-
-   return (0);
-}
-
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-float PNGAPI
-png_get_pixel_aspect_ratio(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-#ifdef PNG_READ_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
-   {
-      png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio");
-
-      if (info_ptr->x_pixels_per_unit != 0)
-         return ((float)((float)info_ptr->y_pixels_per_unit
-             /(float)info_ptr->x_pixels_per_unit));
-   }
-#endif
-
-   return ((float)0.0);
-}
-#endif
-
-#ifdef PNG_FIXED_POINT_SUPPORTED
-png_fixed_point PNGAPI
-png_get_pixel_aspect_ratio_fixed(png_const_structp png_ptr,
-    png_const_infop info_ptr)
-{
-#ifdef PNG_READ_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)
-       && info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0
-       && info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX
-       && info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
-   {
-      png_fixed_point res;
-
-      png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio_fixed");
-
-      /* The following casts work because a PNG 4 byte integer only has a valid
-       * range of 0..2^31-1; otherwise the cast might overflow.
-       */
-      if (png_muldiv(&res, (png_int_32)info_ptr->y_pixels_per_unit, PNG_FP_1,
-          (png_int_32)info_ptr->x_pixels_per_unit))
-         return res;
-   }
-#endif
-
-   return 0;
-}
-#endif
-
-png_int_32 PNGAPI
-png_get_x_offset_microns(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-#ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
-   {
-      png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns");
-
-      if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
-         return (info_ptr->x_offset);
-   }
-#endif
-
-   return (0);
-}
-
-png_int_32 PNGAPI
-png_get_y_offset_microns(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-#ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
-   {
-      png_debug1(1, "in %s retrieval function", "png_get_y_offset_microns");
-
-      if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
-         return (info_ptr->y_offset);
-   }
-#endif
-
-   return (0);
-}
-
-png_int_32 PNGAPI
-png_get_x_offset_pixels(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-#ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
-   {
-      png_debug1(1, "in %s retrieval function", "png_get_x_offset_pixels");
-
-      if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
-         return (info_ptr->x_offset);
-   }
-#endif
-
-   return (0);
-}
-
-png_int_32 PNGAPI
-png_get_y_offset_pixels(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-#ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
-   {
-      png_debug1(1, "in %s retrieval function", "png_get_y_offset_pixels");
-
-      if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
-         return (info_ptr->y_offset);
-   }
-#endif
-
-   return (0);
-}
-
-#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
-static png_uint_32
-ppi_from_ppm(png_uint_32 ppm)
-{
-#if 0
-   /* The conversion is *(2.54/100), in binary (32 digits):
-    * .00000110100000001001110101001001
-    */
-   png_uint_32 t1001, t1101;
-   ppm >>= 1;                  /* .1 */
-   t1001 = ppm + (ppm >> 3);   /* .1001 */
-   t1101 = t1001 + (ppm >> 1); /* .1101 */
-   ppm >>= 20;                 /* .000000000000000000001 */
-   t1101 += t1101 >> 15;       /* .1101000000000001101 */
-   t1001 >>= 11;               /* .000000000001001 */
-   t1001 += t1001 >> 12;       /* .000000000001001000000001001 */
-   ppm += t1001;               /* .000000000001001000001001001 */
-   ppm += t1101;               /* .110100000001001110101001001 */
-   return (ppm + 16) >> 5;/* .00000110100000001001110101001001 */
-#else
-   /* The argument is a PNG unsigned integer, so it is not permitted
-    * to be bigger than 2^31.
-    */
-   png_fixed_point result;
-   if (ppm <= PNG_UINT_31_MAX && png_muldiv(&result, (png_int_32)ppm, 127,
-       5000))
-      return result;
-
-   /* Overflow. */
-   return 0;
-#endif
-}
-
-png_uint_32 PNGAPI
-png_get_pixels_per_inch(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   return ppi_from_ppm(png_get_pixels_per_meter(png_ptr, info_ptr));
-}
-
-png_uint_32 PNGAPI
-png_get_x_pixels_per_inch(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   return ppi_from_ppm(png_get_x_pixels_per_meter(png_ptr, info_ptr));
-}
-
-png_uint_32 PNGAPI
-png_get_y_pixels_per_inch(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   return ppi_from_ppm(png_get_y_pixels_per_meter(png_ptr, info_ptr));
-}
-
-#ifdef PNG_FIXED_POINT_SUPPORTED
-static png_fixed_point
-png_fixed_inches_from_microns(png_structp png_ptr, png_int_32 microns)
-{
-   /* Convert from metres * 1,000,000 to inches * 100,000, meters to
-    * inches is simply *(100/2.54), so we want *(10/2.54) == 500/127.
-    * Notice that this can overflow - a warning is output and 0 is
-    * returned.
-    */
-   return png_muldiv_warn(png_ptr, microns, 500, 127);
-}
-
-png_fixed_point PNGAPI
-png_get_x_offset_inches_fixed(png_structp png_ptr,
-    png_const_infop info_ptr)
-{
-   return png_fixed_inches_from_microns(png_ptr,
-       png_get_x_offset_microns(png_ptr, info_ptr));
-}
-#endif
-
-#ifdef PNG_FIXED_POINT_SUPPORTED
-png_fixed_point PNGAPI
-png_get_y_offset_inches_fixed(png_structp png_ptr,
-    png_const_infop info_ptr)
-{
-   return png_fixed_inches_from_microns(png_ptr,
-       png_get_y_offset_microns(png_ptr, info_ptr));
-}
-#endif
-
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-float PNGAPI
-png_get_x_offset_inches(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   /* To avoid the overflow do the conversion directly in floating
-    * point.
-    */
-   return (float)(png_get_x_offset_microns(png_ptr, info_ptr) * .00003937);
-}
-#endif
-
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-float PNGAPI
-png_get_y_offset_inches(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   /* To avoid the overflow do the conversion directly in floating
-    * point.
-    */
-   return (float)(png_get_y_offset_microns(png_ptr, info_ptr) * .00003937);
-}
-#endif
-
-#ifdef PNG_pHYs_SUPPORTED
-png_uint_32 PNGAPI
-png_get_pHYs_dpi(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
-{
-   png_uint_32 retval = 0;
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
-   {
-      png_debug1(1, "in %s retrieval function", "pHYs");
-
-      if (res_x != NULL)
-      {
-         *res_x = info_ptr->x_pixels_per_unit;
-         retval |= PNG_INFO_pHYs;
-      }
-
-      if (res_y != NULL)
-      {
-         *res_y = info_ptr->y_pixels_per_unit;
-         retval |= PNG_INFO_pHYs;
-      }
-
-      if (unit_type != NULL)
-      {
-         *unit_type = (int)info_ptr->phys_unit_type;
-         retval |= PNG_INFO_pHYs;
-
-         if (*unit_type == 1)
-         {
-            if (res_x != NULL) *res_x = (png_uint_32)(*res_x * .0254 + .50);
-            if (res_y != NULL) *res_y = (png_uint_32)(*res_y * .0254 + .50);
-         }
-      }
-   }
-
-   return (retval);
-}
-#endif /* PNG_pHYs_SUPPORTED */
-#endif  /* PNG_INCH_CONVERSIONS_SUPPORTED */
-
-/* png_get_channels really belongs in here, too, but it's been around longer */
-
-#endif  /* PNG_EASY_ACCESS_SUPPORTED */
-
-png_byte PNGAPI
-png_get_channels(png_const_structp png_ptr, png_const_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return(info_ptr->channels);
-
-   return (0);
-}
-
-png_const_bytep PNGAPI
-png_get_signature(png_const_structp png_ptr, png_infop info_ptr)
-{
-   if (png_ptr != NULL && info_ptr != NULL)
-      return(info_ptr->signature);
-
-   return (NULL);
-}
-
-#ifdef PNG_bKGD_SUPPORTED
-png_uint_32 PNGAPI
-png_get_bKGD(png_const_structp png_ptr, png_infop info_ptr,
-   png_color_16p *background)
-{
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)
-       && background != NULL)
-   {
-      png_debug1(1, "in %s retrieval function", "bKGD");
-
-      *background = &(info_ptr->background);
-      return (PNG_INFO_bKGD);
-   }
-
-   return (0);
-}
-#endif
-
-#ifdef PNG_cHRM_SUPPORTED
-/* The XYZ APIs were added in 1.5.5 to take advantage of the code added at the
- * same time to correct the rgb grayscale coefficient defaults obtained from the
- * cHRM chunk in 1.5.4
- */
-png_uint_32 PNGFAPI
-png_get_cHRM_XYZ_fixed(png_structp png_ptr, png_const_infop info_ptr,
-    png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
-    png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
-    png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
-    png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
-    png_fixed_point *int_blue_Z)
-{
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
-   {
-      png_xy xy;
-      png_XYZ XYZ;
-
-      png_debug1(1, "in %s retrieval function", "cHRM_XYZ");
-
-      xy.whitex = info_ptr->x_white;
-      xy.whitey = info_ptr->y_white;
-      xy.redx = info_ptr->x_red;
-      xy.redy = info_ptr->y_red;
-      xy.greenx = info_ptr->x_green;
-      xy.greeny = info_ptr->y_green;
-      xy.bluex = info_ptr->x_blue;
-      xy.bluey = info_ptr->y_blue;
-
-      /* The *_checked function handles error reporting, so just return 0 if
-       * there is a failure here.
-       */
-      if (png_XYZ_from_xy_checked(png_ptr, &XYZ, xy))
-      {
-         if (int_red_X != NULL)
-            *int_red_X = XYZ.redX;
-         if (int_red_Y != NULL)
-            *int_red_Y = XYZ.redY;
-         if (int_red_Z != NULL)
-            *int_red_Z = XYZ.redZ;
-         if (int_green_X != NULL)
-            *int_green_X = XYZ.greenX;
-         if (int_green_Y != NULL)
-            *int_green_Y = XYZ.greenY;
-         if (int_green_Z != NULL)
-            *int_green_Z = XYZ.greenZ;
-         if (int_blue_X != NULL)
-            *int_blue_X = XYZ.blueX;
-         if (int_blue_Y != NULL)
-            *int_blue_Y = XYZ.blueY;
-         if (int_blue_Z != NULL)
-            *int_blue_Z = XYZ.blueZ;
-
-         return (PNG_INFO_cHRM);
-      }
-   }
-
-   return (0);
-}
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-png_uint_32 PNGAPI
-png_get_cHRM(png_const_structp png_ptr, png_const_infop info_ptr,
-    double *white_x, double *white_y, double *red_x, double *red_y,
-    double *green_x, double *green_y, double *blue_x, double *blue_y)
-{
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
-   {
-      png_debug1(1, "in %s retrieval function", "cHRM");
-
-      if (white_x != NULL)
-         *white_x = png_float(png_ptr, info_ptr->x_white, "cHRM white X");
-      if (white_y != NULL)
-         *white_y = png_float(png_ptr, info_ptr->y_white, "cHRM white Y");
-      if (red_x != NULL)
-         *red_x = png_float(png_ptr, info_ptr->x_red, "cHRM red X");
-      if (red_y != NULL)
-         *red_y = png_float(png_ptr, info_ptr->y_red, "cHRM red Y");
-      if (green_x != NULL)
-         *green_x = png_float(png_ptr, info_ptr->x_green, "cHRM green X");
-      if (green_y != NULL)
-         *green_y = png_float(png_ptr, info_ptr->y_green, "cHRM green Y");
-      if (blue_x != NULL)
-         *blue_x = png_float(png_ptr, info_ptr->x_blue, "cHRM blue X");
-      if (blue_y != NULL)
-         *blue_y = png_float(png_ptr, info_ptr->y_blue, "cHRM blue Y");
-      return (PNG_INFO_cHRM);
-   }
-
-   return (0);
-}
-
-png_uint_32 PNGAPI
-png_get_cHRM_XYZ(png_structp png_ptr, png_const_infop info_ptr,
-   double *red_X, double *red_Y, double *red_Z, double *green_X,
-   double *green_Y, double *green_Z, double *blue_X, double *blue_Y,
-   double *blue_Z)
-{
-   png_XYZ XYZ;
-
-   if (png_get_cHRM_XYZ_fixed(png_ptr, info_ptr,
-      &XYZ.redX, &XYZ.redY, &XYZ.redZ, &XYZ.greenX, &XYZ.greenY, &XYZ.greenZ,
-      &XYZ.blueX, &XYZ.blueY, &XYZ.blueZ) & PNG_INFO_cHRM)
-   {
-      if (red_X != NULL)
-         *red_X = png_float(png_ptr, XYZ.redX, "cHRM red X");
-      if (red_Y != NULL)
-         *red_Y = png_float(png_ptr, XYZ.redY, "cHRM red Y");
-      if (red_Z != NULL)
-         *red_Z = png_float(png_ptr, XYZ.redZ, "cHRM red Z");
-      if (green_X != NULL)
-         *green_X = png_float(png_ptr, XYZ.greenX, "cHRM green X");
-      if (green_Y != NULL)
-         *green_Y = png_float(png_ptr, XYZ.greenY, "cHRM green Y");
-      if (green_Z != NULL)
-         *green_Z = png_float(png_ptr, XYZ.greenZ, "cHRM green Z");
-      if (blue_X != NULL)
-         *blue_X = png_float(png_ptr, XYZ.blueX, "cHRM blue X");
-      if (blue_Y != NULL)
-         *blue_Y = png_float(png_ptr, XYZ.blueY, "cHRM blue Y");
-      if (blue_Z != NULL)
-         *blue_Z = png_float(png_ptr, XYZ.blueZ, "cHRM blue Z");
-      return (PNG_INFO_cHRM);
-   }
-
-   return (0);
-}
-#  endif
-
-#  ifdef PNG_FIXED_POINT_SUPPORTED
-png_uint_32 PNGAPI
-png_get_cHRM_fixed(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_fixed_point *white_x, png_fixed_point *white_y, png_fixed_point *red_x,
-    png_fixed_point *red_y, png_fixed_point *green_x, png_fixed_point *green_y,
-    png_fixed_point *blue_x, png_fixed_point *blue_y)
-{
-   png_debug1(1, "in %s retrieval function", "cHRM");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
-   {
-      if (white_x != NULL)
-         *white_x = info_ptr->x_white;
-      if (white_y != NULL)
-         *white_y = info_ptr->y_white;
-      if (red_x != NULL)
-         *red_x = info_ptr->x_red;
-      if (red_y != NULL)
-         *red_y = info_ptr->y_red;
-      if (green_x != NULL)
-         *green_x = info_ptr->x_green;
-      if (green_y != NULL)
-         *green_y = info_ptr->y_green;
-      if (blue_x != NULL)
-         *blue_x = info_ptr->x_blue;
-      if (blue_y != NULL)
-         *blue_y = info_ptr->y_blue;
-      return (PNG_INFO_cHRM);
-   }
-
-   return (0);
-}
-#  endif
-#endif
-
-#ifdef PNG_gAMA_SUPPORTED
-png_uint_32 PNGFAPI
-png_get_gAMA_fixed(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_fixed_point *file_gamma)
-{
-   png_debug1(1, "in %s retrieval function", "gAMA");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
-       && file_gamma != NULL)
-   {
-      *file_gamma = info_ptr->gamma;
-      return (PNG_INFO_gAMA);
-   }
-
-   return (0);
-}
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-png_uint_32 PNGAPI
-png_get_gAMA(png_const_structp png_ptr, png_const_infop info_ptr,
-    double *file_gamma)
-{
-   png_fixed_point igamma;
-   png_uint_32 ok = png_get_gAMA_fixed(png_ptr, info_ptr, &igamma);
-
-   if (ok)
-      *file_gamma = png_float(png_ptr, igamma, "png_get_gAMA");
-
-   return ok;
-}
-
-#  endif
-#endif
-
-#ifdef PNG_sRGB_SUPPORTED
-png_uint_32 PNGAPI
-png_get_sRGB(png_const_structp png_ptr, png_const_infop info_ptr,
-    int *file_srgb_intent)
-{
-   png_debug1(1, "in %s retrieval function", "sRGB");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB)
-       && file_srgb_intent != NULL)
-   {
-      *file_srgb_intent = (int)info_ptr->srgb_intent;
-      return (PNG_INFO_sRGB);
-   }
-
-   return (0);
-}
-#endif
-
-#ifdef PNG_iCCP_SUPPORTED
-png_uint_32 PNGAPI
-png_get_iCCP(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_charpp name, int *compression_type,
-    png_bytepp profile, png_uint_32 *proflen)
-{
-   png_debug1(1, "in %s retrieval function", "iCCP");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)
-       && name != NULL && compression_type != NULL && profile != NULL &&
-		 proflen != NULL)
-   {
-      *name = info_ptr->iccp_name;
-      *profile = info_ptr->iccp_profile;
-      /* Compression_type is a dummy so the API won't have to change
-       * if we introduce multiple compression types later.
-       */
-      *proflen = info_ptr->iccp_proflen;
-      *compression_type = info_ptr->iccp_compression;
-      return (PNG_INFO_iCCP);
-   }
-
-   return (0);
-}
-#endif
-
-#ifdef PNG_sPLT_SUPPORTED
-png_uint_32 PNGAPI
-png_get_sPLT(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_sPLT_tpp spalettes)
-{
-   if (png_ptr != NULL && info_ptr != NULL && spalettes != NULL)
-   {
-      *spalettes = info_ptr->splt_palettes;
-      return ((png_uint_32)info_ptr->splt_palettes_num);
-   }
-
-   return (0);
-}
-#endif
-
-#ifdef PNG_hIST_SUPPORTED
-png_uint_32 PNGAPI
-png_get_hIST(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_uint_16p *hist)
-{
-   png_debug1(1, "in %s retrieval function", "hIST");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)
-       && hist != NULL)
-   {
-      *hist = info_ptr->hist;
-      return (PNG_INFO_hIST);
-   }
-
-   return (0);
-}
-#endif
-
-png_uint_32 PNGAPI
-png_get_IHDR(png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 *width, png_uint_32 *height, int *bit_depth,
-    int *color_type, int *interlace_type, int *compression_type,
-    int *filter_type)
-
-{
-   png_debug1(1, "in %s retrieval function", "IHDR");
-
-   if (png_ptr == NULL || info_ptr == NULL || width == NULL ||
-       height == NULL || bit_depth == NULL || color_type == NULL)
-      return (0);
-
-   *width = info_ptr->width;
-   *height = info_ptr->height;
-   *bit_depth = info_ptr->bit_depth;
-   *color_type = info_ptr->color_type;
-
-   if (compression_type != NULL)
-      *compression_type = info_ptr->compression_type;
-
-   if (filter_type != NULL)
-      *filter_type = info_ptr->filter_type;
-
-   if (interlace_type != NULL)
-      *interlace_type = info_ptr->interlace_type;
-
-   /* This is redundant if we can be sure that the info_ptr values were all
-    * assigned in png_set_IHDR().  We do the check anyhow in case an
-    * application has ignored our advice not to mess with the members
-    * of info_ptr directly.
-    */
-   png_check_IHDR (png_ptr, info_ptr->width, info_ptr->height,
-       info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
-       info_ptr->compression_type, info_ptr->filter_type);
-
-   return (1);
-}
-
-#ifdef PNG_oFFs_SUPPORTED
-png_uint_32 PNGAPI
-png_get_oFFs(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type)
-{
-   png_debug1(1, "in %s retrieval function", "oFFs");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)
-       && offset_x != NULL && offset_y != NULL && unit_type != NULL)
-   {
-      *offset_x = info_ptr->x_offset;
-      *offset_y = info_ptr->y_offset;
-      *unit_type = (int)info_ptr->offset_unit_type;
-      return (PNG_INFO_oFFs);
-   }
-
-   return (0);
-}
-#endif
-
-#ifdef PNG_pCAL_SUPPORTED
-png_uint_32 PNGAPI
-png_get_pCAL(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type, int *nparams,
-    png_charp *units, png_charpp *params)
-{
-   png_debug1(1, "in %s retrieval function", "pCAL");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)
-       && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
-       nparams != NULL && units != NULL && params != NULL)
-   {
-      *purpose = info_ptr->pcal_purpose;
-      *X0 = info_ptr->pcal_X0;
-      *X1 = info_ptr->pcal_X1;
-      *type = (int)info_ptr->pcal_type;
-      *nparams = (int)info_ptr->pcal_nparams;
-      *units = info_ptr->pcal_units;
-      *params = info_ptr->pcal_params;
-      return (PNG_INFO_pCAL);
-   }
-
-   return (0);
-}
-#endif
-
-#ifdef PNG_sCAL_SUPPORTED
-#  ifdef PNG_FIXED_POINT_SUPPORTED
-#    ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-png_uint_32 PNGAPI
-png_get_sCAL_fixed(png_structp png_ptr, png_const_infop info_ptr,
-    int *unit, png_fixed_point *width, png_fixed_point *height)
-{
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
-   {
-      *unit = info_ptr->scal_unit;
-      /*TODO: make this work without FP support */
-      *width = png_fixed(png_ptr, atof(info_ptr->scal_s_width), "sCAL width");
-      *height = png_fixed(png_ptr, atof(info_ptr->scal_s_height),
-         "sCAL height");
-      return (PNG_INFO_sCAL);
-   }
-
-   return(0);
-}
-#    endif /* FLOATING_ARITHMETIC */
-#  endif /* FIXED_POINT */
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-png_uint_32 PNGAPI
-png_get_sCAL(png_const_structp png_ptr, png_const_infop info_ptr,
-    int *unit, double *width, double *height)
-{
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
-   {
-      *unit = info_ptr->scal_unit;
-      *width = atof(info_ptr->scal_s_width);
-      *height = atof(info_ptr->scal_s_height);
-      return (PNG_INFO_sCAL);
-   }
-
-   return(0);
-}
-#  endif /* FLOATING POINT */
-png_uint_32 PNGAPI
-png_get_sCAL_s(png_const_structp png_ptr, png_const_infop info_ptr,
-    int *unit, png_charpp width, png_charpp height)
-{
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
-   {
-      *unit = info_ptr->scal_unit;
-      *width = info_ptr->scal_s_width;
-      *height = info_ptr->scal_s_height;
-      return (PNG_INFO_sCAL);
-   }
-
-   return(0);
-}
-#endif /* sCAL */
-
-#ifdef PNG_pHYs_SUPPORTED
-png_uint_32 PNGAPI
-png_get_pHYs(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
-{
-   png_uint_32 retval = 0;
-
-   png_debug1(1, "in %s retrieval function", "pHYs");
-
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs))
-   {
-      if (res_x != NULL)
-      {
-         *res_x = info_ptr->x_pixels_per_unit;
-         retval |= PNG_INFO_pHYs;
-      }
-
-      if (res_y != NULL)
-      {
-         *res_y = info_ptr->y_pixels_per_unit;
-         retval |= PNG_INFO_pHYs;
-      }
-
-      if (unit_type != NULL)
-      {
-         *unit_type = (int)info_ptr->phys_unit_type;
-         retval |= PNG_INFO_pHYs;
-      }
-   }
-
-   return (retval);
-}
-#endif /* pHYs */
-
-png_uint_32 PNGAPI
-png_get_PLTE(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_colorp *palette, int *num_palette)
-{
-   png_debug1(1, "in %s retrieval function", "PLTE");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_PLTE)
-       && palette != NULL)
-   {
-      *palette = info_ptr->palette;
-      *num_palette = info_ptr->num_palette;
-      png_debug1(3, "num_palette = %d", *num_palette);
-      return (PNG_INFO_PLTE);
-   }
-
-   return (0);
-}
-
-#ifdef PNG_sBIT_SUPPORTED
-png_uint_32 PNGAPI
-png_get_sBIT(png_const_structp png_ptr, png_infop info_ptr,
-    png_color_8p *sig_bit)
-{
-   png_debug1(1, "in %s retrieval function", "sBIT");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)
-       && sig_bit != NULL)
-   {
-      *sig_bit = &(info_ptr->sig_bit);
-      return (PNG_INFO_sBIT);
-   }
-
-   return (0);
-}
-#endif
-
-#ifdef PNG_TEXT_SUPPORTED
-png_uint_32 PNGAPI
-png_get_text(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_textp *text_ptr, int *num_text)
-{
-   if (png_ptr != NULL && info_ptr != NULL && info_ptr->num_text > 0)
-   {
-      png_debug1(1, "in 0x%lx retrieval function",
-         (unsigned long)png_ptr->chunk_name);
-
-      if (text_ptr != NULL)
-         *text_ptr = info_ptr->text;
-
-      if (num_text != NULL)
-         *num_text = info_ptr->num_text;
-
-      return ((png_uint_32)info_ptr->num_text);
-   }
-
-   if (num_text != NULL)
-      *num_text = 0;
-
-   return(0);
-}
-#endif
-
-#ifdef PNG_tIME_SUPPORTED
-png_uint_32 PNGAPI
-png_get_tIME(png_const_structp png_ptr, png_infop info_ptr, png_timep *mod_time)
-{
-   png_debug1(1, "in %s retrieval function", "tIME");
-
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)
-       && mod_time != NULL)
-   {
-      *mod_time = &(info_ptr->mod_time);
-      return (PNG_INFO_tIME);
-   }
-
-   return (0);
-}
-#endif
-
-#ifdef PNG_tRNS_SUPPORTED
-png_uint_32 PNGAPI
-png_get_tRNS(png_const_structp png_ptr, png_infop info_ptr,
-    png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color)
-{
-   png_uint_32 retval = 0;
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
-   {
-      png_debug1(1, "in %s retrieval function", "tRNS");
-
-      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         if (trans_alpha != NULL)
-         {
-            *trans_alpha = info_ptr->trans_alpha;
-            retval |= PNG_INFO_tRNS;
-         }
-
-         if (trans_color != NULL)
-            *trans_color = &(info_ptr->trans_color);
-      }
-
-      else /* if (info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) */
-      {
-         if (trans_color != NULL)
-         {
-            *trans_color = &(info_ptr->trans_color);
-            retval |= PNG_INFO_tRNS;
-         }
-
-         if (trans_alpha != NULL)
-            *trans_alpha = NULL;
-      }
-
-      if (num_trans != NULL)
-      {
-         *num_trans = info_ptr->num_trans;
-         retval |= PNG_INFO_tRNS;
-      }
-   }
-
-   return (retval);
-}
-#endif
-
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-int PNGAPI
-png_get_unknown_chunks(png_const_structp png_ptr, png_const_infop info_ptr,
-    png_unknown_chunkpp unknowns)
-{
-   if (png_ptr != NULL && info_ptr != NULL && unknowns != NULL)
-   {
-      *unknowns = info_ptr->unknown_chunks;
-      return info_ptr->unknown_chunks_num;
-   }
-
-   return (0);
-}
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-png_byte PNGAPI
-png_get_rgb_to_gray_status (png_const_structp png_ptr)
-{
-   return (png_byte)(png_ptr ? png_ptr->rgb_to_gray_status : 0);
-}
-#endif
-
-#ifdef PNG_USER_CHUNKS_SUPPORTED
-png_voidp PNGAPI
-png_get_user_chunk_ptr(png_const_structp png_ptr)
-{
-   return (png_ptr ? png_ptr->user_chunk_ptr : NULL);
-}
-#endif
-
-png_size_t PNGAPI
-png_get_compression_buffer_size(png_const_structp png_ptr)
-{
-   return (png_ptr ? png_ptr->zbuf_size : 0);
-}
-
-#ifdef PNG_SET_USER_LIMITS_SUPPORTED
-/* These functions were added to libpng 1.2.6 and were enabled
- * by default in libpng-1.4.0 */
-png_uint_32 PNGAPI
-png_get_user_width_max (png_const_structp png_ptr)
-{
-   return (png_ptr ? png_ptr->user_width_max : 0);
-}
-
-png_uint_32 PNGAPI
-png_get_user_height_max (png_const_structp png_ptr)
-{
-   return (png_ptr ? png_ptr->user_height_max : 0);
-}
-
-/* This function was added to libpng 1.4.0 */
-png_uint_32 PNGAPI
-png_get_chunk_cache_max (png_const_structp png_ptr)
-{
-   return (png_ptr ? png_ptr->user_chunk_cache_max : 0);
-}
-
-/* This function was added to libpng 1.4.1 */
-png_alloc_size_t PNGAPI
-png_get_chunk_malloc_max (png_const_structp png_ptr)
-{
-   return (png_ptr ? png_ptr->user_chunk_malloc_max : 0);
-}
-#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */
-
-/* These functions were added to libpng 1.4.0 */
-#ifdef PNG_IO_STATE_SUPPORTED
-png_uint_32 PNGAPI
-png_get_io_state (png_structp png_ptr)
-{
-   return png_ptr->io_state;
-}
-
-png_uint_32 PNGAPI
-png_get_io_chunk_type (png_const_structp png_ptr)
-{
-   return png_ptr->chunk_name;
-}
-
-png_const_bytep PNGAPI
-png_get_io_chunk_name (png_structp png_ptr)
-{
-   PNG_CSTRING_FROM_CHUNK(png_ptr->io_chunk_string, png_ptr->chunk_name);
-   return png_ptr->io_chunk_string;
-}
-#endif /* ?PNG_IO_STATE_SUPPORTED */
-
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/extern/libpng/include/pnginfo.h b/extern/libpng/include/pnginfo.h
deleted file mode 100644
index a33bfab06d..0000000000
--- a/extern/libpng/include/pnginfo.h
+++ /dev/null
@@ -1,269 +0,0 @@
-
-/* pnginfo.h - header file for PNG reference library
- *
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * Last changed in libpng 1.5.0 [January 6, 2011]
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
- /* png_info is a structure that holds the information in a PNG file so
- * that the application can find out the characteristics of the image.
- * If you are reading the file, this structure will tell you what is
- * in the PNG file.  If you are writing the file, fill in the information
- * you want to put into the PNG file, using png_set_*() functions, then
- * call png_write_info().
- *
- * The names chosen should be very close to the PNG specification, so
- * consult that document for information about the meaning of each field.
- *
- * With libpng < 0.95, it was only possible to directly set and read the
- * the values in the png_info_struct, which meant that the contents and
- * order of the values had to remain fixed.  With libpng 0.95 and later,
- * however, there are now functions that abstract the contents of
- * png_info_struct from the application, so this makes it easier to use
- * libpng with dynamic libraries, and even makes it possible to use
- * libraries that don't have all of the libpng ancillary chunk-handing
- * functionality.  In libpng-1.5.0 this was moved into a separate private
- * file that is not visible to applications.
- *
- * The following members may have allocated storage attached that should be
- * cleaned up before the structure is discarded: palette, trans, text,
- * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
- * splt_palettes, scal_unit, row_pointers, and unknowns.   By default, these
- * are automatically freed when the info structure is deallocated, if they were
- * allocated internally by libpng.  This behavior can be changed by means
- * of the png_data_freer() function.
- *
- * More allocation details: all the chunk-reading functions that
- * change these members go through the corresponding png_set_*
- * functions.  A function to clear these members is available: see
- * png_free_data().  The png_set_* functions do not depend on being
- * able to point info structure members to any of the storage they are
- * passed (they make their own copies), EXCEPT that the png_set_text
- * functions use the same storage passed to them in the text_ptr or
- * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
- * functions do not make their own copies.
- */
-#ifndef PNGINFO_H
-#define PNGINFO_H
-
-struct png_info_def
-{
-   /* the following are necessary for every PNG file */
-   png_uint_32 width;  /* width of image in pixels (from IHDR) */
-   png_uint_32 height; /* height of image in pixels (from IHDR) */
-   png_uint_32 valid;  /* valid chunk data (see PNG_INFO_ below) */
-   png_size_t rowbytes; /* bytes needed to hold an untransformed row */
-   png_colorp palette;      /* array of color values (valid & PNG_INFO_PLTE) */
-   png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
-   png_uint_16 num_trans;   /* number of transparent palette color (tRNS) */
-   png_byte bit_depth;      /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
-   png_byte color_type;     /* see PNG_COLOR_TYPE_ below (from IHDR) */
-   /* The following three should have been named *_method not *_type */
-   png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
-   png_byte filter_type;    /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
-   png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
-
-   /* The following is informational only on read, and not used on writes. */
-   png_byte channels;       /* number of data channels per pixel (1, 2, 3, 4) */
-   png_byte pixel_depth;    /* number of bits per pixel */
-   png_byte spare_byte;     /* to align the data, and for future use */
-   png_byte signature[8];   /* magic bytes read by libpng from start of file */
-
-   /* The rest of the data is optional.  If you are reading, check the
-    * valid field to see if the information in these are valid.  If you
-    * are writing, set the valid field to those chunks you want written,
-    * and initialize the appropriate fields below.
-    */
-
-#if defined(PNG_gAMA_SUPPORTED)
-   /* The gAMA chunk describes the gamma characteristics of the system
-    * on which the image was created, normally in the range [1.0, 2.5].
-    * Data is valid if (valid & PNG_INFO_gAMA) is non-zero.
-    */
-   png_fixed_point gamma;
-#endif
-
-#ifdef PNG_sRGB_SUPPORTED
-    /* GR-P, 0.96a */
-    /* Data valid if (valid & PNG_INFO_sRGB) non-zero. */
-   png_byte srgb_intent; /* sRGB rendering intent [0, 1, 2, or 3] */
-#endif
-
-#ifdef PNG_TEXT_SUPPORTED
-   /* The tEXt, and zTXt chunks contain human-readable textual data in
-    * uncompressed, compressed, and optionally compressed forms, respectively.
-    * The data in "text" is an array of pointers to uncompressed,
-    * null-terminated C strings. Each chunk has a keyword that describes the
-    * textual data contained in that chunk.  Keywords are not required to be
-    * unique, and the text string may be empty.  Any number of text chunks may
-    * be in an image.
-    */
-   int num_text; /* number of comments read or comments to write */
-   int max_text; /* current size of text array */
-   png_textp text; /* array of comments read or comments to write */
-#endif /* PNG_TEXT_SUPPORTED */
-
-#ifdef PNG_tIME_SUPPORTED
-   /* The tIME chunk holds the last time the displayed image data was
-    * modified.  See the png_time struct for the contents of this struct.
-    */
-   png_time mod_time;
-#endif
-
-#ifdef PNG_sBIT_SUPPORTED
-   /* The sBIT chunk specifies the number of significant high-order bits
-    * in the pixel data.  Values are in the range [1, bit_depth], and are
-    * only specified for the channels in the pixel data.  The contents of
-    * the low-order bits is not specified.  Data is valid if
-    * (valid & PNG_INFO_sBIT) is non-zero.
-    */
-   png_color_8 sig_bit; /* significant bits in color channels */
-#endif
-
-#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
-defined(PNG_READ_BACKGROUND_SUPPORTED)
-   /* The tRNS chunk supplies transparency data for paletted images and
-    * other image types that don't need a full alpha channel.  There are
-    * "num_trans" transparency values for a paletted image, stored in the
-    * same order as the palette colors, starting from index 0.  Values
-    * for the data are in the range [0, 255], ranging from fully transparent
-    * to fully opaque, respectively.  For non-paletted images, there is a
-    * single color specified that should be treated as fully transparent.
-    * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
-    */
-   png_bytep trans_alpha;    /* alpha values for paletted image */
-   png_color_16 trans_color; /* transparent color for non-palette image */
-#endif
-
-#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
-   /* The bKGD chunk gives the suggested image background color if the
-    * display program does not have its own background color and the image
-    * is needs to composited onto a background before display.  The colors
-    * in "background" are normally in the same color space/depth as the
-    * pixel data.  Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
-    */
-   png_color_16 background;
-#endif
-
-#ifdef PNG_oFFs_SUPPORTED
-   /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
-    * and downwards from the top-left corner of the display, page, or other
-    * application-specific co-ordinate space.  See the PNG_OFFSET_ defines
-    * below for the unit types.  Valid if (valid & PNG_INFO_oFFs) non-zero.
-    */
-   png_int_32 x_offset; /* x offset on page */
-   png_int_32 y_offset; /* y offset on page */
-   png_byte offset_unit_type; /* offset units type */
-#endif
-
-#ifdef PNG_pHYs_SUPPORTED
-   /* The pHYs chunk gives the physical pixel density of the image for
-    * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
-    * defines below).  Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
-    */
-   png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
-   png_uint_32 y_pixels_per_unit; /* vertical pixel density */
-   png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
-#endif
-
-#ifdef PNG_hIST_SUPPORTED
-   /* The hIST chunk contains the relative frequency or importance of the
-    * various palette entries, so that a viewer can intelligently select a
-    * reduced-color palette, if required.  Data is an array of "num_palette"
-    * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
-    * is non-zero.
-    */
-   png_uint_16p hist;
-#endif
-
-#ifdef PNG_cHRM_SUPPORTED
-   /* The cHRM chunk describes the CIE color characteristics of the monitor
-    * on which the PNG was created.  This data allows the viewer to do gamut
-    * mapping of the input image to ensure that the viewer sees the same
-    * colors in the image as the creator.  Values are in the range
-    * [0.0, 0.8].  Data valid if (valid & PNG_INFO_cHRM) non-zero.
-    */
-   png_fixed_point x_white;
-   png_fixed_point y_white;
-   png_fixed_point x_red;
-   png_fixed_point y_red;
-   png_fixed_point x_green;
-   png_fixed_point y_green;
-   png_fixed_point x_blue;
-   png_fixed_point y_blue;
-#endif
-
-#ifdef PNG_pCAL_SUPPORTED
-   /* The pCAL chunk describes a transformation between the stored pixel
-    * values and original physical data values used to create the image.
-    * The integer range [0, 2^bit_depth - 1] maps to the floating-point
-    * range given by [pcal_X0, pcal_X1], and are further transformed by a
-    * (possibly non-linear) transformation function given by "pcal_type"
-    * and "pcal_params" into "pcal_units".  Please see the PNG_EQUATION_
-    * defines below, and the PNG-Group's PNG extensions document for a
-    * complete description of the transformations and how they should be
-    * implemented, and for a description of the ASCII parameter strings.
-    * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
-    */
-   png_charp pcal_purpose;  /* pCAL chunk description string */
-   png_int_32 pcal_X0;      /* minimum value */
-   png_int_32 pcal_X1;      /* maximum value */
-   png_charp pcal_units;    /* Latin-1 string giving physical units */
-   png_charpp pcal_params;  /* ASCII strings containing parameter values */
-   png_byte pcal_type;      /* equation type (see PNG_EQUATION_ below) */
-   png_byte pcal_nparams;   /* number of parameters given in pcal_params */
-#endif
-
-/* New members added in libpng-1.0.6 */
-   png_uint_32 free_me;     /* flags items libpng is responsible for freeing */
-
-#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) || \
- defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
-   /* Storage for unknown chunks that the library doesn't recognize. */
-   png_unknown_chunkp unknown_chunks;
-   int unknown_chunks_num;
-#endif
-
-#ifdef PNG_iCCP_SUPPORTED
-   /* iCCP chunk data. */
-   png_charp iccp_name;     /* profile name */
-   png_bytep iccp_profile;  /* International Color Consortium profile data */
-   png_uint_32 iccp_proflen;  /* ICC profile data length */
-   png_byte iccp_compression; /* Always zero */
-#endif
-
-#ifdef PNG_sPLT_SUPPORTED
-   /* Data on sPLT chunks (there may be more than one). */
-   png_sPLT_tp splt_palettes;
-   png_uint_32 splt_palettes_num;
-#endif
-
-#ifdef PNG_sCAL_SUPPORTED
-   /* The sCAL chunk describes the actual physical dimensions of the
-    * subject matter of the graphic.  The chunk contains a unit specification
-    * a byte value, and two ASCII strings representing floating-point
-    * values.  The values are width and height corresponsing to one pixel
-    * in the image.  Data values are valid if (valid & PNG_INFO_sCAL) is
-    * non-zero.
-    */
-   png_byte scal_unit;         /* unit of physical scale */
-   png_charp scal_s_width;     /* string containing height */
-   png_charp scal_s_height;    /* string containing width */
-#endif
-
-#ifdef PNG_INFO_IMAGE_SUPPORTED
-   /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS)
-      non-zero */
-   /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
-   png_bytepp row_pointers;        /* the image bits */
-#endif
-
-};
-#endif /* PNGINFO_H */
diff --git a/extern/libpng/include/pnglibconf.h b/extern/libpng/include/pnglibconf.h
deleted file mode 100644
index 6facf39aab..0000000000
--- a/extern/libpng/include/pnglibconf.h
+++ /dev/null
@@ -1,186 +0,0 @@
-
-/* libpng STANDARD API DEFINITION */
-
-/* pnglibconf.h - library build configuration */
-
-/* Libpng 1.5.10 - March 29, 2012 */
-
-/* Copyright (c) 1998-2012 Glenn Randers-Pehrson */
-
-/* This code is released under the libpng license. */
-/* For conditions of distribution and use, see the disclaimer */
-/* and license in png.h */
-
-/* pnglibconf.h */
-/* Derived from: scripts/pnglibconf.dfa */
-/* If you edit this file by hand you must obey the rules expressed in */
-/* pnglibconf.dfa with respect to the dependencies between the following */
-/* symbols.  It is much better to generate a new file using */
-/* scripts/libpngconf.mak */
-
-#ifndef PNGLCONF_H
-#define PNGLCONF_H
-/* settings */
-#define PNG_API_RULE 0
-#define PNG_CALLOC_SUPPORTED
-#define PNG_COST_SHIFT 3
-#define PNG_DEFAULT_READ_MACROS 1
-#define PNG_GAMMA_THRESHOLD_FIXED 5000
-#define PNG_MAX_GAMMA_8 11
-#define PNG_QUANTIZE_BLUE_BITS 5
-#define PNG_QUANTIZE_GREEN_BITS 5
-#define PNG_QUANTIZE_RED_BITS 5
-#define PNG_sCAL_PRECISION 5
-#define PNG_WEIGHT_SHIFT 8
-#define PNG_ZBUF_SIZE 8192
-/* end of settings */
-/* options */
-#define PNG_16BIT_SUPPORTED
-#define PNG_ALIGN_MEMORY_SUPPORTED
-#define PNG_BENIGN_ERRORS_SUPPORTED
-#define PNG_bKGD_SUPPORTED
-#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
-#define PNG_CHECK_cHRM_SUPPORTED
-#define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
-#define PNG_cHRM_SUPPORTED
-#define PNG_CONSOLE_IO_SUPPORTED
-#define PNG_CONVERT_tIME_SUPPORTED
-#define PNG_EASY_ACCESS_SUPPORTED
-/*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
-#define PNG_ERROR_TEXT_SUPPORTED
-#define PNG_FIXED_POINT_SUPPORTED
-#define PNG_FLOATING_ARITHMETIC_SUPPORTED
-#define PNG_FLOATING_POINT_SUPPORTED
-#define PNG_gAMA_SUPPORTED
-#define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-#define PNG_hIST_SUPPORTED
-#define PNG_iCCP_SUPPORTED
-#define PNG_INCH_CONVERSIONS_SUPPORTED
-#define PNG_INFO_IMAGE_SUPPORTED
-#define PNG_IO_STATE_SUPPORTED
-#define PNG_iTXt_SUPPORTED
-#define PNG_MNG_FEATURES_SUPPORTED
-#define PNG_oFFs_SUPPORTED
-#define PNG_pCAL_SUPPORTED
-#define PNG_pHYs_SUPPORTED
-#define PNG_POINTER_INDEXING_SUPPORTED
-#define PNG_PROGRESSIVE_READ_SUPPORTED
-#define PNG_READ_16BIT_SUPPORTED
-#define PNG_READ_ALPHA_MODE_SUPPORTED
-#define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
-#define PNG_READ_BACKGROUND_SUPPORTED
-#define PNG_READ_BGR_SUPPORTED
-#define PNG_READ_bKGD_SUPPORTED
-#define PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
-#define PNG_READ_cHRM_SUPPORTED
-#define PNG_READ_COMPOSITE_NODIV_SUPPORTED
-#define PNG_READ_COMPRESSED_TEXT_SUPPORTED
-#define PNG_READ_EXPAND_16_SUPPORTED
-#define PNG_READ_EXPAND_SUPPORTED
-#define PNG_READ_FILLER_SUPPORTED
-#define PNG_READ_gAMA_SUPPORTED
-#define PNG_READ_GAMMA_SUPPORTED
-#define PNG_READ_GRAY_TO_RGB_SUPPORTED
-#define PNG_READ_hIST_SUPPORTED
-#define PNG_READ_iCCP_SUPPORTED
-#define PNG_READ_INTERLACING_SUPPORTED
-#define PNG_READ_INT_FUNCTIONS_SUPPORTED
-#define PNG_READ_INVERT_ALPHA_SUPPORTED
-#define PNG_READ_INVERT_SUPPORTED
-#define PNG_READ_iTXt_SUPPORTED
-#define PNG_READ_oFFs_SUPPORTED
-#define PNG_READ_OPT_PLTE_SUPPORTED
-#define PNG_READ_PACK_SUPPORTED
-#define PNG_READ_PACKSWAP_SUPPORTED
-#define PNG_READ_pCAL_SUPPORTED
-#define PNG_READ_pHYs_SUPPORTED
-#define PNG_READ_QUANTIZE_SUPPORTED
-#define PNG_READ_RGB_TO_GRAY_SUPPORTED
-#define PNG_READ_sBIT_SUPPORTED
-#define PNG_READ_SCALE_16_TO_8_SUPPORTED
-#define PNG_READ_sCAL_SUPPORTED
-#define PNG_READ_SHIFT_SUPPORTED
-#define PNG_READ_sPLT_SUPPORTED
-#define PNG_READ_sRGB_SUPPORTED
-#define PNG_READ_STRIP_16_TO_8_SUPPORTED
-#define PNG_READ_STRIP_ALPHA_SUPPORTED
-#define PNG_READ_SUPPORTED
-#define PNG_READ_SWAP_ALPHA_SUPPORTED
-#define PNG_READ_SWAP_SUPPORTED
-#define PNG_READ_tEXt_SUPPORTED
-#define PNG_READ_TEXT_SUPPORTED
-#define PNG_READ_tIME_SUPPORTED
-#define PNG_READ_TRANSFORMS_SUPPORTED
-#define PNG_READ_tRNS_SUPPORTED
-#define PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
-#define PNG_READ_USER_CHUNKS_SUPPORTED
-#define PNG_READ_USER_TRANSFORM_SUPPORTED
-#define PNG_READ_zTXt_SUPPORTED
-#define PNG_SAVE_INT_32_SUPPORTED
-#define PNG_sBIT_SUPPORTED
-#define PNG_sCAL_SUPPORTED
-#define PNG_SEQUENTIAL_READ_SUPPORTED
-#define PNG_SET_CHUNK_CACHE_LIMIT_SUPPORTED
-#define PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
-#define PNG_SETJMP_SUPPORTED
-#define PNG_SET_USER_LIMITS_SUPPORTED
-#define PNG_sPLT_SUPPORTED
-#define PNG_sRGB_SUPPORTED
-#define PNG_STDIO_SUPPORTED
-#define PNG_tEXt_SUPPORTED
-#define PNG_TEXT_SUPPORTED
-#define PNG_TIME_RFC1123_SUPPORTED
-#define PNG_tIME_SUPPORTED
-#define PNG_tRNS_SUPPORTED
-#define PNG_UNKNOWN_CHUNKS_SUPPORTED
-#define PNG_USER_CHUNKS_SUPPORTED
-#define PNG_USER_LIMITS_SUPPORTED
-#define PNG_USER_MEM_SUPPORTED
-#define PNG_USER_TRANSFORM_INFO_SUPPORTED
-#define PNG_USER_TRANSFORM_PTR_SUPPORTED
-#define PNG_WARNINGS_SUPPORTED
-#define PNG_WRITE_16BIT_SUPPORTED
-#define PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED
-#define PNG_WRITE_BGR_SUPPORTED
-#define PNG_WRITE_bKGD_SUPPORTED
-#define PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
-#define PNG_WRITE_cHRM_SUPPORTED
-#define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
-#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
-#define PNG_WRITE_FILLER_SUPPORTED
-#define PNG_WRITE_FILTER_SUPPORTED
-#define PNG_WRITE_FLUSH_SUPPORTED
-#define PNG_WRITE_gAMA_SUPPORTED
-#define PNG_WRITE_hIST_SUPPORTED
-#define PNG_WRITE_iCCP_SUPPORTED
-#define PNG_WRITE_INTERLACING_SUPPORTED
-#define PNG_WRITE_INT_FUNCTIONS_SUPPORTED
-#define PNG_WRITE_INVERT_ALPHA_SUPPORTED
-#define PNG_WRITE_INVERT_SUPPORTED
-#define PNG_WRITE_iTXt_SUPPORTED
-#define PNG_WRITE_oFFs_SUPPORTED
-#define PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-#define PNG_WRITE_PACK_SUPPORTED
-#define PNG_WRITE_PACKSWAP_SUPPORTED
-#define PNG_WRITE_pCAL_SUPPORTED
-#define PNG_WRITE_pHYs_SUPPORTED
-#define PNG_WRITE_sBIT_SUPPORTED
-#define PNG_WRITE_sCAL_SUPPORTED
-#define PNG_WRITE_SHIFT_SUPPORTED
-#define PNG_WRITE_sPLT_SUPPORTED
-#define PNG_WRITE_sRGB_SUPPORTED
-#define PNG_WRITE_SUPPORTED
-#define PNG_WRITE_SWAP_ALPHA_SUPPORTED
-#define PNG_WRITE_SWAP_SUPPORTED
-#define PNG_WRITE_tEXt_SUPPORTED
-#define PNG_WRITE_TEXT_SUPPORTED
-#define PNG_WRITE_tIME_SUPPORTED
-#define PNG_WRITE_TRANSFORMS_SUPPORTED
-#define PNG_WRITE_tRNS_SUPPORTED
-#define PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-#define PNG_WRITE_USER_TRANSFORM_SUPPORTED
-#define PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-#define PNG_WRITE_zTXt_SUPPORTED
-#define PNG_zTXt_SUPPORTED
-/* end of options */
-#endif /* PNGLCONF_H */
diff --git a/extern/libpng/include/pngmem.c b/extern/libpng/include/pngmem.c
deleted file mode 100644
index bf5ff037da..0000000000
--- a/extern/libpng/include/pngmem.c
+++ /dev/null
@@ -1,667 +0,0 @@
-
-/* pngmem.c - stub functions for memory allocation
- *
- * Last changed in libpng 1.5.7 [December 15, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * This file provides a location for all memory allocation.  Users who
- * need special memory handling are expected to supply replacement
- * functions for png_malloc() and png_free(), and to use
- * png_create_read_struct_2() and png_create_write_struct_2() to
- * identify the replacement functions.
- */
-
-#include "pngpriv.h"
-
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-
-/* Borland DOS special memory handler */
-#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
-/* If you change this, be sure to change the one in png.h also */
-
-/* Allocate memory for a png_struct.  The malloc and memset can be replaced
-   by a single call to calloc() if this is thought to improve performance. */
-PNG_FUNCTION(png_voidp /* PRIVATE */,
-png_create_struct,(int type),PNG_ALLOCATED)
-{
-#  ifdef PNG_USER_MEM_SUPPORTED
-   return (png_create_struct_2(type, NULL, NULL));
-}
-
-/* Alternate version of png_create_struct, for use with user-defined malloc. */
-PNG_FUNCTION(png_voidp /* PRIVATE */,
-png_create_struct_2,(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr),
-   PNG_ALLOCATED)
-{
-#  endif /* PNG_USER_MEM_SUPPORTED */
-   png_size_t size;
-   png_voidp struct_ptr;
-
-   if (type == PNG_STRUCT_INFO)
-      size = png_sizeof(png_info);
-
-   else if (type == PNG_STRUCT_PNG)
-      size = png_sizeof(png_struct);
-
-   else
-      return (png_get_copyright(NULL));
-
-#  ifdef PNG_USER_MEM_SUPPORTED
-   if (malloc_fn != NULL)
-   {
-      png_struct dummy_struct;
-      memset(&dummy_struct, 0, sizeof dummy_struct);
-      dummy_struct.mem_ptr=mem_ptr;
-      struct_ptr = (*(malloc_fn))(&dummy_struct, (png_alloc_size_t)size);
-   }
-
-   else
-#  endif /* PNG_USER_MEM_SUPPORTED */
-   struct_ptr = (png_voidp)farmalloc(size);
-   if (struct_ptr != NULL)
-      png_memset(struct_ptr, 0, size);
-
-   return (struct_ptr);
-}
-
-/* Free memory allocated by a png_create_struct() call */
-void /* PRIVATE */
-png_destroy_struct(png_voidp struct_ptr)
-{
-#  ifdef PNG_USER_MEM_SUPPORTED
-   png_destroy_struct_2(struct_ptr, NULL, NULL);
-}
-
-/* Free memory allocated by a png_create_struct() call */
-void /* PRIVATE */
-png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
-    png_voidp mem_ptr)
-{
-#  endif
-   if (struct_ptr != NULL)
-   {
-#  ifdef PNG_USER_MEM_SUPPORTED
-      if (free_fn != NULL)
-      {
-         png_struct dummy_struct;
-         memset(&dummy_struct, 0, sizeof dummy_struct);
-         dummy_struct.mem_ptr=mem_ptr;
-         (*(free_fn))(&dummy_struct, struct_ptr);
-         return;
-      }
-
-#  endif /* PNG_USER_MEM_SUPPORTED */
-      farfree (struct_ptr);
-   }
-}
-
-/* Allocate memory.  For reasonable files, size should never exceed
- * 64K.  However, zlib may allocate more then 64K if you don't tell
- * it not to.  See zconf.h and png.h for more information. zlib does
- * need to allocate exactly 64K, so whatever you call here must
- * have the ability to do that.
- *
- * Borland seems to have a problem in DOS mode for exactly 64K.
- * It gives you a segment with an offset of 8 (perhaps to store its
- * memory stuff).  zlib doesn't like this at all, so we have to
- * detect and deal with it.  This code should not be needed in
- * Windows or OS/2 modes, and only in 16 bit mode.  This code has
- * been updated by Alexander Lehmann for version 0.89 to waste less
- * memory.
- *
- * Note that we can't use png_size_t for the "size" declaration,
- * since on some systems a png_size_t is a 16-bit quantity, and as a
- * result, we would be truncating potentially larger memory requests
- * (which should cause a fatal error) and introducing major problems.
- */
-PNG_FUNCTION(png_voidp,PNGAPI
-png_calloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
-{
-   png_voidp ret;
-
-   ret = (png_malloc(png_ptr, size));
-
-   if (ret != NULL)
-      png_memset(ret,0,(png_size_t)size);
-
-   return (ret);
-}
-
-PNG_FUNCTION(png_voidp,PNGAPI
-png_malloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
-{
-   png_voidp ret;
-
-   if (png_ptr == NULL || size == 0)
-      return (NULL);
-
-#  ifdef PNG_USER_MEM_SUPPORTED
-   if (png_ptr->malloc_fn != NULL)
-      ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, size));
-
-   else
-      ret = (png_malloc_default(png_ptr, size));
-
-   if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
-       png_error(png_ptr, "Out of memory");
-
-   return (ret);
-}
-
-PNG_FUNCTION(png_voidp,PNGAPI
-png_malloc_default,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
-{
-   png_voidp ret;
-#  endif /* PNG_USER_MEM_SUPPORTED */
-
-   if (png_ptr == NULL || size == 0)
-      return (NULL);
-
-#  ifdef PNG_MAX_MALLOC_64K
-   if (size > (png_uint_32)65536L)
-   {
-      png_warning(png_ptr, "Cannot Allocate > 64K");
-      ret = NULL;
-   }
-
-   else
-#  endif
-
-   if (size != (size_t)size)
-      ret = NULL;
-
-   else if (size == (png_uint_32)65536L)
-   {
-      if (png_ptr->offset_table == NULL)
-      {
-         /* Try to see if we need to do any of this fancy stuff */
-         ret = farmalloc(size);
-         if (ret == NULL || ((png_size_t)ret & 0xffff))
-         {
-            int num_blocks;
-            png_uint_32 total_size;
-            png_bytep table;
-            int i, mem_level, window_bits;
-            png_byte huge * hptr;
-            int window_bits
-
-            if (ret != NULL)
-            {
-               farfree(ret);
-               ret = NULL;
-            }
-
-            window_bits =
-                png_ptr->zlib_window_bits >= png_ptr->zlib_text_window_bits ?
-                png_ptr->zlib_window_bits : png_ptr->zlib_text_window_bits;
-
-            if (window_bits > 14)
-               num_blocks = (int)(1 << (window_bits - 14));
-
-            else
-               num_blocks = 1;
-
-            mem_level =
-                png_ptr->zlib_mem_level >= png_ptr->zlib_text_mem_level ?
-                png_ptr->zlib_mem_level : png_ptr->zlib_text_mem_level;
-
-            if (mem_level >= 7)
-               num_blocks += (int)(1 << (mem_level - 7));
-
-            else
-               num_blocks++;
-
-            total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;
-
-            table = farmalloc(total_size);
-
-            if (table == NULL)
-            {
-#  ifndef PNG_USER_MEM_SUPPORTED
-               if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
-                  png_error(png_ptr, "Out Of Memory"); /* Note "O", "M" */
-
-               else
-                  png_warning(png_ptr, "Out Of Memory");
-#  endif
-               return (NULL);
-            }
-
-            if ((png_size_t)table & 0xfff0)
-            {
-#  ifndef PNG_USER_MEM_SUPPORTED
-               if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
-                  png_error(png_ptr,
-                    "Farmalloc didn't return normalized pointer");
-
-               else
-                  png_warning(png_ptr,
-                    "Farmalloc didn't return normalized pointer");
-#  endif
-               return (NULL);
-            }
-
-            png_ptr->offset_table = table;
-            png_ptr->offset_table_ptr = farmalloc(num_blocks *
-               png_sizeof(png_bytep));
-
-            if (png_ptr->offset_table_ptr == NULL)
-            {
-#  ifndef PNG_USER_MEM_SUPPORTED
-               if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
-                  png_error(png_ptr, "Out Of memory"); /* Note "O", "m" */
-
-               else
-                  png_warning(png_ptr, "Out Of memory");
-#  endif
-               return (NULL);
-            }
-
-            hptr = (png_byte huge *)table;
-            if ((png_size_t)hptr & 0xf)
-            {
-               hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
-               hptr = hptr + 16L;  /* "hptr += 16L" fails on Turbo C++ 3.0 */
-            }
-
-            for (i = 0; i < num_blocks; i++)
-            {
-               png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
-               hptr = hptr + (png_uint_32)65536L;  /* "+=" fails on TC++3.0 */
-            }
-
-            png_ptr->offset_table_number = num_blocks;
-            png_ptr->offset_table_count = 0;
-            png_ptr->offset_table_count_free = 0;
-         }
-      }
-
-      if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
-      {
-#  ifndef PNG_USER_MEM_SUPPORTED
-         if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
-            png_error(png_ptr, "Out of Memory"); /* Note "O" and "M" */
-
-         else
-            png_warning(png_ptr, "Out of Memory");
-#  endif
-         return (NULL);
-      }
-
-      ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
-   }
-
-   else
-      ret = farmalloc(size);
-
-#  ifndef PNG_USER_MEM_SUPPORTED
-   if (ret == NULL)
-   {
-      if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
-         png_error(png_ptr, "Out of memory"); /* Note "o" and "m" */
-
-      else
-         png_warning(png_ptr, "Out of memory"); /* Note "o" and "m" */
-   }
-#  endif
-
-   return (ret);
-}
-
-/* Free a pointer allocated by png_malloc().  In the default
- * configuration, png_ptr is not used, but is passed in case it
- * is needed.  If ptr is NULL, return without taking any action.
- */
-void PNGAPI
-png_free(png_structp png_ptr, png_voidp ptr)
-{
-   if (png_ptr == NULL || ptr == NULL)
-      return;
-
-#  ifdef PNG_USER_MEM_SUPPORTED
-   if (png_ptr->free_fn != NULL)
-   {
-      (*(png_ptr->free_fn))(png_ptr, ptr);
-      return;
-   }
-
-   else
-      png_free_default(png_ptr, ptr);
-}
-
-void PNGAPI
-png_free_default(png_structp png_ptr, png_voidp ptr)
-{
-#  endif /* PNG_USER_MEM_SUPPORTED */
-
-   if (png_ptr == NULL || ptr == NULL)
-      return;
-
-   if (png_ptr->offset_table != NULL)
-   {
-      int i;
-
-      for (i = 0; i < png_ptr->offset_table_count; i++)
-      {
-         if (ptr == png_ptr->offset_table_ptr[i])
-         {
-            ptr = NULL;
-            png_ptr->offset_table_count_free++;
-            break;
-         }
-      }
-      if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
-      {
-         farfree(png_ptr->offset_table);
-         farfree(png_ptr->offset_table_ptr);
-         png_ptr->offset_table = NULL;
-         png_ptr->offset_table_ptr = NULL;
-      }
-   }
-
-   if (ptr != NULL)
-      farfree(ptr);
-}
-
-#else /* Not the Borland DOS special memory handler */
-
-/* Allocate memory for a png_struct or a png_info.  The malloc and
-   memset can be replaced by a single call to calloc() if this is thought
-   to improve performance noticably. */
-PNG_FUNCTION(png_voidp /* PRIVATE */,
-png_create_struct,(int type),PNG_ALLOCATED)
-{
-#  ifdef PNG_USER_MEM_SUPPORTED
-   return (png_create_struct_2(type, NULL, NULL));
-}
-
-/* Allocate memory for a png_struct or a png_info.  The malloc and
-   memset can be replaced by a single call to calloc() if this is thought
-   to improve performance noticably. */
-PNG_FUNCTION(png_voidp /* PRIVATE */,
-png_create_struct_2,(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr),
-   PNG_ALLOCATED)
-{
-#  endif /* PNG_USER_MEM_SUPPORTED */
-   png_size_t size;
-   png_voidp struct_ptr;
-
-   if (type == PNG_STRUCT_INFO)
-      size = png_sizeof(png_info);
-
-   else if (type == PNG_STRUCT_PNG)
-      size = png_sizeof(png_struct);
-
-   else
-      return (NULL);
-
-#  ifdef PNG_USER_MEM_SUPPORTED
-   if (malloc_fn != NULL)
-   {
-      png_struct dummy_struct;
-      png_structp png_ptr = &dummy_struct;
-      png_ptr->mem_ptr=mem_ptr;
-      struct_ptr = (*(malloc_fn))(png_ptr, size);
-
-      if (struct_ptr != NULL)
-         png_memset(struct_ptr, 0, size);
-
-      return (struct_ptr);
-   }
-#  endif /* PNG_USER_MEM_SUPPORTED */
-
-#  if defined(__TURBOC__) && !defined(__FLAT__)
-   struct_ptr = (png_voidp)farmalloc(size);
-#  else
-#    if defined(_MSC_VER) && defined(MAXSEG_64K)
-   struct_ptr = (png_voidp)halloc(size, 1);
-#    else
-   struct_ptr = (png_voidp)malloc(size);
-#    endif
-#  endif
-
-   if (struct_ptr != NULL)
-      png_memset(struct_ptr, 0, size);
-
-   return (struct_ptr);
-}
-
-
-/* Free memory allocated by a png_create_struct() call */
-void /* PRIVATE */
-png_destroy_struct(png_voidp struct_ptr)
-{
-#  ifdef PNG_USER_MEM_SUPPORTED
-   png_destroy_struct_2(struct_ptr, NULL, NULL);
-}
-
-/* Free memory allocated by a png_create_struct() call */
-void /* PRIVATE */
-png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
-    png_voidp mem_ptr)
-{
-#  endif /* PNG_USER_MEM_SUPPORTED */
-   if (struct_ptr != NULL)
-   {
-#  ifdef PNG_USER_MEM_SUPPORTED
-      if (free_fn != NULL)
-      {
-         png_struct dummy_struct;
-         png_structp png_ptr = &dummy_struct;
-         png_ptr->mem_ptr=mem_ptr;
-         (*(free_fn))(png_ptr, struct_ptr);
-         return;
-      }
-#  endif /* PNG_USER_MEM_SUPPORTED */
-#  if defined(__TURBOC__) && !defined(__FLAT__)
-      farfree(struct_ptr);
-
-#  else
-#    if defined(_MSC_VER) && defined(MAXSEG_64K)
-      hfree(struct_ptr);
-
-#    else
-      free(struct_ptr);
-
-#    endif
-#  endif
-   }
-}
-
-/* Allocate memory.  For reasonable files, size should never exceed
- * 64K.  However, zlib may allocate more then 64K if you don't tell
- * it not to.  See zconf.h and png.h for more information.  zlib does
- * need to allocate exactly 64K, so whatever you call here must
- * have the ability to do that.
- */
-
-PNG_FUNCTION(png_voidp,PNGAPI
-png_calloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
-{
-   png_voidp ret;
-
-   ret = (png_malloc(png_ptr, size));
-
-   if (ret != NULL)
-      png_memset(ret,0,(png_size_t)size);
-
-   return (ret);
-}
-
-PNG_FUNCTION(png_voidp,PNGAPI
-png_malloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
-{
-   png_voidp ret;
-
-#  ifdef PNG_USER_MEM_SUPPORTED
-   if (png_ptr == NULL || size == 0)
-      return (NULL);
-
-   if (png_ptr->malloc_fn != NULL)
-      ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
-
-   else
-      ret = (png_malloc_default(png_ptr, size));
-
-   if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
-       png_error(png_ptr, "Out of Memory");
-
-   return (ret);
-}
-
-PNG_FUNCTION(png_voidp,PNGAPI
-png_malloc_default,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
-{
-   png_voidp ret;
-#  endif /* PNG_USER_MEM_SUPPORTED */
-
-   if (png_ptr == NULL || size == 0)
-      return (NULL);
-
-#  ifdef PNG_MAX_MALLOC_64K
-   if (size > (png_uint_32)65536L)
-   {
-#    ifndef PNG_USER_MEM_SUPPORTED
-      if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
-         png_error(png_ptr, "Cannot Allocate > 64K");
-
-      else
-#    endif
-         return NULL;
-   }
-#  endif
-
-   /* Check for overflow */
-#  if defined(__TURBOC__) && !defined(__FLAT__)
-
-   if (size != (unsigned long)size)
-      ret = NULL;
-
-   else
-      ret = farmalloc(size);
-
-#  else
-#    if defined(_MSC_VER) && defined(MAXSEG_64K)
-   if (size != (unsigned long)size)
-      ret = NULL;
-
-   else
-      ret = halloc(size, 1);
-
-#    else
-   if (size != (size_t)size)
-      ret = NULL;
-
-   else
-      ret = malloc((size_t)size);
-#    endif
-#  endif
-
-#  ifndef PNG_USER_MEM_SUPPORTED
-   if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
-      png_error(png_ptr, "Out of Memory");
-#  endif
-
-   return (ret);
-}
-
-/* Free a pointer allocated by png_malloc().  If ptr is NULL, return
- * without taking any action.
- */
-void PNGAPI
-png_free(png_structp png_ptr, png_voidp ptr)
-{
-   if (png_ptr == NULL || ptr == NULL)
-      return;
-
-#  ifdef PNG_USER_MEM_SUPPORTED
-   if (png_ptr->free_fn != NULL)
-   {
-      (*(png_ptr->free_fn))(png_ptr, ptr);
-      return;
-   }
-
-   else
-      png_free_default(png_ptr, ptr);
-}
-
-void PNGAPI
-png_free_default(png_structp png_ptr, png_voidp ptr)
-{
-   if (png_ptr == NULL || ptr == NULL)
-      return;
-
-#  endif /* PNG_USER_MEM_SUPPORTED */
-
-#  if defined(__TURBOC__) && !defined(__FLAT__)
-   farfree(ptr);
-
-#  else
-#    if defined(_MSC_VER) && defined(MAXSEG_64K)
-   hfree(ptr);
-
-#    else
-   free(ptr);
-
-#    endif
-#  endif
-}
-#endif /* Not Borland DOS special memory handler */
-
-/* This function was added at libpng version 1.2.3.  The png_malloc_warn()
- * function will set up png_malloc() to issue a png_warning and return NULL
- * instead of issuing a png_error, if it fails to allocate the requested
- * memory.
- */
-PNG_FUNCTION(png_voidp,PNGAPI
-png_malloc_warn,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
-{
-   png_voidp ptr;
-   png_uint_32 save_flags;
-   if (png_ptr == NULL)
-      return (NULL);
-
-   save_flags = png_ptr->flags;
-   png_ptr->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
-   ptr = (png_voidp)png_malloc((png_structp)png_ptr, size);
-   png_ptr->flags=save_flags;
-   return(ptr);
-}
-
-
-#ifdef PNG_USER_MEM_SUPPORTED
-/* This function is called when the application wants to use another method
- * of allocating and freeing memory.
- */
-void PNGAPI
-png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
-  malloc_fn, png_free_ptr free_fn)
-{
-   if (png_ptr != NULL)
-   {
-      png_ptr->mem_ptr = mem_ptr;
-      png_ptr->malloc_fn = malloc_fn;
-      png_ptr->free_fn = free_fn;
-   }
-}
-
-/* This function returns a pointer to the mem_ptr associated with the user
- * functions.  The application should free any memory associated with this
- * pointer before png_write_destroy and png_read_destroy are called.
- */
-png_voidp PNGAPI
-png_get_mem_ptr(png_const_structp png_ptr)
-{
-   if (png_ptr == NULL)
-      return (NULL);
-
-   return ((png_voidp)png_ptr->mem_ptr);
-}
-#endif /* PNG_USER_MEM_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/extern/libpng/include/pngnow.png b/extern/libpng/include/pngnow.png
deleted file mode 100644
index 82793ebddb7863266a66ffc6ab2c01ca32100808..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 2069
zcmWkudpuN&7T#y<o7ZOO?uNrAM`M(Bqr(m{w;MC#)h4E)!`WVA8`6x?7}PYRX;947
zYi{S{OgK0lO7ci3y*zsHQ=-nPq!KFhKE-q<-MN3P^{sFHv3}ogt?#$?MT7@gnAw>D
z0ALXk%;6bOV2GtAMuxod+KXid08{<L`~jeOzqvl?9|rzS7B46OXdFad8i-SJFfR-M
z<O~2PPyxVaL#yBg0A#NQfayd4@ckJ8Y%;ayB3S@HNs7SvT>XL`q<{m10|OLLYbYp~
zqD01zCx~<rUrv(wDk5D$q|5jM66ZCL!U?@lJK%v40urR?F^^gO;DEkd3z<P`DT;f*
zbW2DU03*(HI>Qa;aTH3$83tYNL5@^&dW%qu3E?~lv;*N57-E2|bs(K#(iIEOmeFx%
zkcfvMOG`)&LHQ673#pIPl0s5bu0h@0>CO<}7a`Ws2_Xc#K~M$^F+q|Eqco5dLWna2
z#X^t(LKq<CfuKw}ClE(yFyaW(-Bw|~ESLu3p*T$Y7F)*w7lEWeq&if~k4?s73B-|(
z*dauG8XiqR6cA-%WR8LmN>oD8nRJmzN=KPsmsFupvRG!&XgFV8A;Y6t95Zm1LFa^q
z^92erLk2B|aULIYLrE_dC!DV+A~6Qa3B~AUAmL0W(=n6@Y2+%tkPyj9RsagyA*csN
zrps7?xTc~3G=mlSYRm(ZDb=D31>#001TxH*!;$k@LY&S-QNy%At*T6qc|mvuj(MT{
zShXyF6!Ad#Eru11piDK&6sbyVIXSpO33CD<Rv>}%6q-XYOk*K|bUdDgx`AW{hwjYa
zM<-xjEZA^`|H~$2a<yJa!izz~5#h&^EZ_Br9ZCp9Bn@UQwo=%^Fa^ZSKoJdw93i?R
zsHMS*90*wis%Wt02+Z<@dL8LF4eoNLql-X=974??RnY<15)?@bMCpna%>>8bLQKZ}
zLB^Jd#VHvwfGx?~A>ERiCUg3J?OJcAAZbdf6Hk&Nk_fY$mS?2o%GPH}1d{E{WQll1
z=-8g42GdW4aQykf``V&Q6W}O#EGzZC`E*NWZcMk35*qfRc}Z6Nnc{k=W$S9olPI;+
z@nk_TpA-koOx36tuc^5+8y2dJKCX$4z2CENV(>!in*_$fq1N2jW1W6k7j=WW!K2we
zQx6hfTZ3TdyW^y&(Mek}jvhFo%!~{*FP%!sE17a%?j{}9boS=;RS0g0Vl+OX*4!KG
zS9cV3_T@Rcztag#Ba8Akz?VEN{KY|&-cj^8X4hI9rOS7jb^I*rs9{W6y2#E2G^qzi
zdmWmqMl3bFs8=?8X$*f<{;;}lLq<aErk&T0<vw!gcs_PHFT^CBy}c_N_r3dVI6}4g
z^`o@-<+%=%TyDgFDO@$rrLyk}mG#4Uk&aDuZ>--wF|=g=DWXjt<5enf565lt)AmHV
zIxOb73llA}$8Ct~8-~_=j#_ZB`OnsJr4>ai);+T_!|ZPhrkXB?{B)};+#9l2+7C4G
z(7Hc=^#UXHmZ|>h%+um(yvmbWw|yz{+FO@id!cP~py}<7RoWpJ*Fa-`$lS+tJjBR&
z6tlD4Ti8JxCZ<oj)kn9)bof1rv#;FCx_{x_in-y^iXBI|-s0CUv$^L#cmH?@ZR{bd
zZcC*@8`~R~ZqInDE4TUU-c6h0`1Jdq-rru?yt$pazl-MSV%}d`@-e2haCu#{-pB9Z
zFgh~tgcZLid*3@_-=KRCek#Q_C;Q_`peOE&m%00*n`~Ql4DV)LA0b%6K&Z}MO{!H7
zrq0=w9+^+9lf+9J;#VnyYbA3P-ebu9zoVBc_t}QsEu@+o<yi+p$JXpcu9-X=YBycV
zov4eT?b{}JUfuf!UD1Do+vUA5cu|lHMZYe7ZDjoTUmX`d-Cmfhx;k6hY5weN_0<a(
z1%j<BimGtf_@4>9NMtT44qLLkP~+BFVn!|dbm^=AtK$C64)M~7nwq6^V!syIo2Oxw
z>Q`G3RCIQRk}|{IuYEXq#p2PEEha{j+{?DX0X|%93;f$J-{g|;y0D)gO{G>+cUcD`
z4y@ax<21CZK45QAznB)#Ufr}OXGc|jX9Ltdv+b8XbyW6-6`@zUuVY!hSGtpO`!`Qz
z&NQEk%buN|_~W2YVMOhus;$a%yh2m*KG^m|>9yn4nuBHYyEpCJ)0$=<bSQ^;97(x3
zqVa4$=elgzb>kK9Wtr0td+%|?D^-C{{MH<3%xF3Nr{}sKhiFd5L0;yj%{mN`D2E@j
zb9elGv{mRmpa=e4(SIT%(x!E1a$=RXWcVrny?jLXA=RCjub+PYvh*imzV73lzO2;z
z^IhX}vi&XOSKIaiO6bz9{*4VIPX4pcSiyJsOr)&7MIV0tt;fiC&DW%|Q{u`km5!dp
z!Uvmke~-D&46c>G#Z1ofQ!2y69!2#V?{T-pgjb1Z<)$Z0{jJ!Cd*WSVOiYG2O~X$e
zkOZV!x9`)jqV>P+UU{SXLBcfJe~UZ${fApm5?rT^HZwk-)*@r4(symdMMs05ch4L&
zKD%kQ5%->$aqgk4nHpEI84+blJ(2ds3O8Z;4>JTe4@PSyKg=thMLwxcsc|nVEJ)aH
z*B04qWpUia=q@`HDRXoAnzt<~x%EzDW7^4`nuh7CO5MicxId`hJsvyinB5bmk2>6A
rInt*5>ynshr7qiTo&3Aj@9hWbNS~fK{3iQ`;bQ_J+;C1~K%(-0k;znQ

diff --git a/extern/libpng/include/pngpread.c b/extern/libpng/include/pngpread.c
deleted file mode 100644
index 8a5aa29ec8..0000000000
--- a/extern/libpng/include/pngpread.c
+++ /dev/null
@@ -1,1314 +0,0 @@
-
-/* pngpread.c - read a png file in push mode
- *
- * Last changed in libpng 1.5.9 [February 18, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-
-/* Push model modes */
-#define PNG_READ_SIG_MODE   0
-#define PNG_READ_CHUNK_MODE 1
-#define PNG_READ_IDAT_MODE  2
-#define PNG_SKIP_MODE       3
-#define PNG_READ_tEXt_MODE  4
-#define PNG_READ_zTXt_MODE  5
-#define PNG_READ_DONE_MODE  6
-#define PNG_READ_iTXt_MODE  7
-#define PNG_ERROR_MODE      8
-
-void PNGAPI
-png_process_data(png_structp png_ptr, png_infop info_ptr,
-    png_bytep buffer, png_size_t buffer_size)
-{
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   png_push_restore_buffer(png_ptr, buffer, buffer_size);
-
-   while (png_ptr->buffer_size)
-   {
-      png_process_some_data(png_ptr, info_ptr);
-   }
-}
-
-png_size_t PNGAPI
-png_process_data_pause(png_structp png_ptr, int save)
-{
-   if (png_ptr != NULL)
-   {
-      /* It's easiest for the caller if we do the save, then the caller doesn't
-       * have to supply the same data again:
-       */
-      if (save)
-         png_push_save_buffer(png_ptr);
-      else
-      {
-         /* This includes any pending saved bytes: */
-         png_size_t remaining = png_ptr->buffer_size;
-         png_ptr->buffer_size = 0;
-
-         /* So subtract the saved buffer size, unless all the data
-          * is actually 'saved', in which case we just return 0
-          */
-         if (png_ptr->save_buffer_size < remaining)
-            return remaining - png_ptr->save_buffer_size;
-      }
-   }
-
-   return 0;
-}
-
-png_uint_32 PNGAPI
-png_process_data_skip(png_structp png_ptr)
-{
-   png_uint_32 remaining = 0;
-
-   if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE &&
-      png_ptr->skip_length > 0)
-   {
-      /* At the end of png_process_data the buffer size must be 0 (see the loop
-       * above) so we can detect a broken call here:
-       */
-      if (png_ptr->buffer_size != 0)
-         png_error(png_ptr,
-            "png_process_data_skip called inside png_process_data");
-
-      /* If is impossible for there to be a saved buffer at this point -
-       * otherwise we could not be in SKIP mode.  This will also happen if
-       * png_process_skip is called inside png_process_data (but only very
-       * rarely.)
-       */
-      if (png_ptr->save_buffer_size != 0)
-         png_error(png_ptr, "png_process_data_skip called with saved data");
-
-      remaining = png_ptr->skip_length;
-      png_ptr->skip_length = 0;
-      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-   }
-
-   return remaining;
-}
-
-/* What we do with the incoming data depends on what we were previously
- * doing before we ran out of data...
- */
-void /* PRIVATE */
-png_process_some_data(png_structp png_ptr, png_infop info_ptr)
-{
-   if (png_ptr == NULL)
-      return;
-
-   switch (png_ptr->process_mode)
-   {
-      case PNG_READ_SIG_MODE:
-      {
-         png_push_read_sig(png_ptr, info_ptr);
-         break;
-      }
-
-      case PNG_READ_CHUNK_MODE:
-      {
-         png_push_read_chunk(png_ptr, info_ptr);
-         break;
-      }
-
-      case PNG_READ_IDAT_MODE:
-      {
-         png_push_read_IDAT(png_ptr);
-         break;
-      }
-
-      case PNG_SKIP_MODE:
-      {
-         png_push_crc_finish(png_ptr);
-         break;
-      }
-
-      default:
-      {
-         png_ptr->buffer_size = 0;
-         break;
-      }
-   }
-}
-
-/* Read any remaining signature bytes from the stream and compare them with
- * the correct PNG signature.  It is possible that this routine is called
- * with bytes already read from the signature, either because they have been
- * checked by the calling application, or because of multiple calls to this
- * routine.
- */
-void /* PRIVATE */
-png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
-{
-   png_size_t num_checked = png_ptr->sig_bytes,
-       num_to_check = 8 - num_checked;
-
-   if (png_ptr->buffer_size < num_to_check)
-   {
-      num_to_check = png_ptr->buffer_size;
-   }
-
-   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
-       num_to_check);
-   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
-
-   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
-   {
-      if (num_checked < 4 &&
-          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
-         png_error(png_ptr, "Not a PNG file");
-
-      else
-         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
-   }
-
-   else
-   {
-      if (png_ptr->sig_bytes >= 8)
-      {
-         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-      }
-   }
-}
-
-void /* PRIVATE */
-png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
-{
-   png_uint_32 chunk_name;
-
-   /* First we make sure we have enough data for the 4 byte chunk name
-    * and the 4 byte chunk length before proceeding with decoding the
-    * chunk data.  To fully decode each of these chunks, we also make
-    * sure we have enough data in the buffer for the 4 byte CRC at the
-    * end of every chunk (except IDAT, which is handled separately).
-    */
-   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
-   {
-      png_byte chunk_length[4];
-      png_byte chunk_tag[4];
-
-      if (png_ptr->buffer_size < 8)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_push_fill_buffer(png_ptr, chunk_length, 4);
-      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
-      png_reset_crc(png_ptr);
-      png_crc_read(png_ptr, chunk_tag, 4);
-      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
-      png_check_chunk_name(png_ptr, png_ptr->chunk_name);
-      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
-   }
-
-   chunk_name = png_ptr->chunk_name;
-
-   if (chunk_name == png_IDAT)
-   {
-      /* This is here above the if/else case statement below because if the
-       * unknown handling marks 'IDAT' as unknown then the IDAT handling case is
-       * completely skipped.
-       *
-       * TODO: there must be a better way of doing this.
-       */
-      if (png_ptr->mode & PNG_AFTER_IDAT)
-         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
-   }
-
-   if (chunk_name == png_IHDR)
-   {
-      if (png_ptr->push_length != 13)
-         png_error(png_ptr, "Invalid IHDR length");
-
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-   else if (chunk_name == png_IEND)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
-
-      png_ptr->process_mode = PNG_READ_DONE_MODE;
-      png_push_have_end(png_ptr, info_ptr);
-   }
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-   else if (png_chunk_unknown_handling(png_ptr, chunk_name))
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      if (chunk_name == png_IDAT)
-         png_ptr->mode |= PNG_HAVE_IDAT;
-
-      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
-
-      if (chunk_name == png_PLTE)
-         png_ptr->mode |= PNG_HAVE_PLTE;
-
-      else if (chunk_name == png_IDAT)
-      {
-         if (!(png_ptr->mode & PNG_HAVE_IHDR))
-            png_error(png_ptr, "Missing IHDR before IDAT");
-
-         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-             !(png_ptr->mode & PNG_HAVE_PLTE))
-            png_error(png_ptr, "Missing PLTE before IDAT");
-      }
-   }
-
-#endif
-   else if (chunk_name == png_PLTE)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-   else if (chunk_name == png_IDAT)
-   {
-      /* If we reach an IDAT chunk, this means we have read all of the
-       * header chunks, and we can start reading the image (or if this
-       * is called after the image has been read - we have an error).
-       */
-
-      if (!(png_ptr->mode & PNG_HAVE_IHDR))
-         png_error(png_ptr, "Missing IHDR before IDAT");
-
-      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-          !(png_ptr->mode & PNG_HAVE_PLTE))
-         png_error(png_ptr, "Missing PLTE before IDAT");
-
-      if (png_ptr->mode & PNG_HAVE_IDAT)
-      {
-         if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
-            if (png_ptr->push_length == 0)
-               return;
-
-         if (png_ptr->mode & PNG_AFTER_IDAT)
-            png_benign_error(png_ptr, "Too many IDATs found");
-      }
-
-      png_ptr->idat_size = png_ptr->push_length;
-      png_ptr->mode |= PNG_HAVE_IDAT;
-      png_ptr->process_mode = PNG_READ_IDAT_MODE;
-      png_push_have_info(png_ptr, info_ptr);
-      png_ptr->zstream.avail_out =
-          (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
-          png_ptr->iwidth) + 1;
-      png_ptr->zstream.next_out = png_ptr->row_buf;
-      return;
-   }
-
-#ifdef PNG_READ_gAMA_SUPPORTED
-   else if (png_ptr->chunk_name == png_gAMA)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sBIT_SUPPORTED
-   else if (png_ptr->chunk_name == png_sBIT)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_cHRM_SUPPORTED
-   else if (png_ptr->chunk_name == png_cHRM)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sRGB_SUPPORTED
-   else if (chunk_name == png_sRGB)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_iCCP_SUPPORTED
-   else if (png_ptr->chunk_name == png_iCCP)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sPLT_SUPPORTED
-   else if (chunk_name == png_sPLT)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_tRNS_SUPPORTED
-   else if (chunk_name == png_tRNS)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_bKGD_SUPPORTED
-   else if (chunk_name == png_bKGD)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_hIST_SUPPORTED
-   else if (chunk_name == png_hIST)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_pHYs_SUPPORTED
-   else if (chunk_name == png_pHYs)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_oFFs_SUPPORTED
-   else if (chunk_name == png_oFFs)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
-   }
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-   else if (chunk_name == png_pCAL)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sCAL_SUPPORTED
-   else if (chunk_name == png_sCAL)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_tIME_SUPPORTED
-   else if (chunk_name == png_tIME)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_tEXt_SUPPORTED
-   else if (chunk_name == png_tEXt)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_zTXt_SUPPORTED
-   else if (chunk_name == png_zTXt)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_iTXt_SUPPORTED
-   else if (chunk_name == png_iTXt)
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-   else
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
-}
-
-void /* PRIVATE */
-png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
-{
-   png_ptr->process_mode = PNG_SKIP_MODE;
-   png_ptr->skip_length = skip;
-}
-
-void /* PRIVATE */
-png_push_crc_finish(png_structp png_ptr)
-{
-   if (png_ptr->skip_length && png_ptr->save_buffer_size)
-   {
-      png_size_t save_size = png_ptr->save_buffer_size;
-      png_uint_32 skip_length = png_ptr->skip_length;
-
-      /* We want the smaller of 'skip_length' and 'save_buffer_size', but
-       * they are of different types and we don't know which variable has the
-       * fewest bits.  Carefully select the smaller and cast it to the type of
-       * the larger - this cannot overflow.  Do not cast in the following test
-       * - it will break on either 16 or 64 bit platforms.
-       */
-      if (skip_length < save_size)
-         save_size = (png_size_t)skip_length;
-
-      else
-         skip_length = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
-      png_ptr->skip_length -= skip_length;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->save_buffer_size -= save_size;
-      png_ptr->save_buffer_ptr += save_size;
-   }
-
-   if (png_ptr->skip_length && png_ptr->current_buffer_size)
-   {
-      png_size_t save_size = png_ptr->current_buffer_size;
-      png_uint_32 skip_length = png_ptr->skip_length;
-
-      /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
-       * the same problem exists as above and the same solution.
-       */
-      if (skip_length < save_size)
-         save_size = (png_size_t)skip_length;
-
-      else
-         skip_length = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
-      png_ptr->skip_length -= skip_length;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->current_buffer_size -= save_size;
-      png_ptr->current_buffer_ptr += save_size;
-   }
-
-   if (!png_ptr->skip_length)
-   {
-      if (png_ptr->buffer_size < 4)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_crc_finish(png_ptr, 0);
-      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-   }
-}
-
-void PNGCBAPI
-png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
-{
-   png_bytep ptr;
-
-   if (png_ptr == NULL)
-      return;
-
-   ptr = buffer;
-
-   if (png_ptr->save_buffer_size)
-   {
-      png_size_t save_size;
-
-      if (length < png_ptr->save_buffer_size)
-         save_size = length;
-
-      else
-         save_size = png_ptr->save_buffer_size;
-
-      png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
-      length -= save_size;
-      ptr += save_size;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->save_buffer_size -= save_size;
-      png_ptr->save_buffer_ptr += save_size;
-   }
-
-   if (length && png_ptr->current_buffer_size)
-   {
-      png_size_t save_size;
-
-      if (length < png_ptr->current_buffer_size)
-         save_size = length;
-
-      else
-         save_size = png_ptr->current_buffer_size;
-
-      png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
-      png_ptr->buffer_size -= save_size;
-      png_ptr->current_buffer_size -= save_size;
-      png_ptr->current_buffer_ptr += save_size;
-   }
-}
-
-void /* PRIVATE */
-png_push_save_buffer(png_structp png_ptr)
-{
-   if (png_ptr->save_buffer_size)
-   {
-      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
-      {
-         png_size_t i, istop;
-         png_bytep sp;
-         png_bytep dp;
-
-         istop = png_ptr->save_buffer_size;
-
-         for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
-             i < istop; i++, sp++, dp++)
-         {
-            *dp = *sp;
-         }
-      }
-   }
-
-   if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
-       png_ptr->save_buffer_max)
-   {
-      png_size_t new_max;
-      png_bytep old_buffer;
-
-      if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
-          (png_ptr->current_buffer_size + 256))
-      {
-         png_error(png_ptr, "Potential overflow of save_buffer");
-      }
-
-      new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
-      old_buffer = png_ptr->save_buffer;
-      png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr, new_max);
-
-      if (png_ptr->save_buffer == NULL)
-      {
-         png_free(png_ptr, old_buffer);
-         png_error(png_ptr, "Insufficient memory for save_buffer");
-      }
-
-      png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
-      png_free(png_ptr, old_buffer);
-      png_ptr->save_buffer_max = new_max;
-   }
-
-   if (png_ptr->current_buffer_size)
-   {
-      png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
-         png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
-      png_ptr->save_buffer_size += png_ptr->current_buffer_size;
-      png_ptr->current_buffer_size = 0;
-   }
-
-   png_ptr->save_buffer_ptr = png_ptr->save_buffer;
-   png_ptr->buffer_size = 0;
-}
-
-void /* PRIVATE */
-png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
-   png_size_t buffer_length)
-{
-   png_ptr->current_buffer = buffer;
-   png_ptr->current_buffer_size = buffer_length;
-   png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
-   png_ptr->current_buffer_ptr = png_ptr->current_buffer;
-}
-
-void /* PRIVATE */
-png_push_read_IDAT(png_structp png_ptr)
-{
-   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
-   {
-      png_byte chunk_length[4];
-      png_byte chunk_tag[4];
-
-      /* TODO: this code can be commoned up with the same code in push_read */
-      if (png_ptr->buffer_size < 8)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_push_fill_buffer(png_ptr, chunk_length, 4);
-      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
-      png_reset_crc(png_ptr);
-      png_crc_read(png_ptr, chunk_tag, 4);
-      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
-      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
-
-      if (png_ptr->chunk_name != png_IDAT)
-      {
-         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-
-         if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
-            png_error(png_ptr, "Not enough compressed data");
-
-         return;
-      }
-
-      png_ptr->idat_size = png_ptr->push_length;
-   }
-
-   if (png_ptr->idat_size && png_ptr->save_buffer_size)
-   {
-      png_size_t save_size = png_ptr->save_buffer_size;
-      png_uint_32 idat_size = png_ptr->idat_size;
-
-      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
-       * are of different types and we don't know which variable has the fewest
-       * bits.  Carefully select the smaller and cast it to the type of the
-       * larger - this cannot overflow.  Do not cast in the following test - it
-       * will break on either 16 or 64 bit platforms.
-       */
-      if (idat_size < save_size)
-         save_size = (png_size_t)idat_size;
-
-      else
-         idat_size = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
-      png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
-      png_ptr->idat_size -= idat_size;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->save_buffer_size -= save_size;
-      png_ptr->save_buffer_ptr += save_size;
-   }
-
-   if (png_ptr->idat_size && png_ptr->current_buffer_size)
-   {
-      png_size_t save_size = png_ptr->current_buffer_size;
-      png_uint_32 idat_size = png_ptr->idat_size;
-
-      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
-       * are of different types and we don't know which variable has the fewest
-       * bits.  Carefully select the smaller and cast it to the type of the
-       * larger - this cannot overflow.
-       */
-      if (idat_size < save_size)
-         save_size = (png_size_t)idat_size;
-
-      else
-         idat_size = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
-      png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
-      png_ptr->idat_size -= idat_size;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->current_buffer_size -= save_size;
-      png_ptr->current_buffer_ptr += save_size;
-   }
-
-   if (!png_ptr->idat_size)
-   {
-      if (png_ptr->buffer_size < 4)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
-      png_crc_finish(png_ptr, 0);
-      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
-      png_ptr->mode |= PNG_AFTER_IDAT;
-   }
-}
-
-void /* PRIVATE */
-png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
-   png_size_t buffer_length)
-{
-   /* The caller checks for a non-zero buffer length. */
-   if (!(buffer_length > 0) || buffer == NULL)
-      png_error(png_ptr, "No IDAT data (internal error)");
-
-   /* This routine must process all the data it has been given
-    * before returning, calling the row callback as required to
-    * handle the uncompressed results.
-    */
-   png_ptr->zstream.next_in = buffer;
-   png_ptr->zstream.avail_in = (uInt)buffer_length;
-
-   /* Keep going until the decompressed data is all processed
-    * or the stream marked as finished.
-    */
-   while (png_ptr->zstream.avail_in > 0 &&
-          !(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
-   {
-      int ret;
-
-      /* We have data for zlib, but we must check that zlib
-       * has someplace to put the results.  It doesn't matter
-       * if we don't expect any results -- it may be the input
-       * data is just the LZ end code.
-       */
-      if (!(png_ptr->zstream.avail_out > 0))
-      {
-         png_ptr->zstream.avail_out =
-             (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
-             png_ptr->iwidth) + 1;
-
-         png_ptr->zstream.next_out = png_ptr->row_buf;
-      }
-
-      /* Using Z_SYNC_FLUSH here means that an unterminated
-       * LZ stream (a stream with a missing end code) can still
-       * be handled, otherwise (Z_NO_FLUSH) a future zlib
-       * implementation might defer output and therefore
-       * change the current behavior (see comments in inflate.c
-       * for why this doesn't happen at present with zlib 1.2.5).
-       */
-      ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
-
-      /* Check for any failure before proceeding. */
-      if (ret != Z_OK && ret != Z_STREAM_END)
-      {
-         /* Terminate the decompression. */
-         png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
-
-         /* This may be a truncated stream (missing or
-          * damaged end code).  Treat that as a warning.
-          */
-         if (png_ptr->row_number >= png_ptr->num_rows ||
-             png_ptr->pass > 6)
-            png_warning(png_ptr, "Truncated compressed data in IDAT");
-
-         else
-            png_error(png_ptr, "Decompression error in IDAT");
-
-         /* Skip the check on unprocessed input */
-         return;
-      }
-
-      /* Did inflate output any data? */
-      if (png_ptr->zstream.next_out != png_ptr->row_buf)
-      {
-         /* Is this unexpected data after the last row?
-          * If it is, artificially terminate the LZ output
-          * here.
-          */
-         if (png_ptr->row_number >= png_ptr->num_rows ||
-             png_ptr->pass > 6)
-         {
-            /* Extra data. */
-            png_warning(png_ptr, "Extra compressed data in IDAT");
-            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
-
-            /* Do no more processing; skip the unprocessed
-             * input check below.
-             */
-            return;
-         }
-
-         /* Do we have a complete row? */
-         if (png_ptr->zstream.avail_out == 0)
-            png_push_process_row(png_ptr);
-      }
-
-      /* And check for the end of the stream. */
-      if (ret == Z_STREAM_END)
-         png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
-   }
-
-   /* All the data should have been processed, if anything
-    * is left at this point we have bytes of IDAT data
-    * after the zlib end code.
-    */
-   if (png_ptr->zstream.avail_in > 0)
-      png_warning(png_ptr, "Extra compression data in IDAT");
-}
-
-void /* PRIVATE */
-png_push_process_row(png_structp png_ptr)
-{
-   /* 1.5.6: row_info moved out of png_struct to a local here. */
-   png_row_info row_info;
-
-   row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
-   row_info.color_type = png_ptr->color_type;
-   row_info.bit_depth = png_ptr->bit_depth;
-   row_info.channels = png_ptr->channels;
-   row_info.pixel_depth = png_ptr->pixel_depth;
-   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
-
-   if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
-   {
-      if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
-         png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
-            png_ptr->prev_row + 1, png_ptr->row_buf[0]);
-      else
-         png_error(png_ptr, "bad adaptive filter value");
-   }
-
-   /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
-    * 1.5.6, while the buffer really is this big in current versions of libpng
-    * it may not be in the future, so this was changed just to copy the
-    * interlaced row count:
-    */
-   png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-   if (png_ptr->transformations)
-      png_do_read_transformations(png_ptr, &row_info);
-#endif
-
-   /* The transformed pixel depth should match the depth now in row_info. */
-   if (png_ptr->transformed_pixel_depth == 0)
-   {
-      png_ptr->transformed_pixel_depth = row_info.pixel_depth;
-      if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
-         png_error(png_ptr, "progressive row overflow");
-   }
-
-   else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
-      png_error(png_ptr, "internal progressive row size calculation error");
-
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Blow up interlaced rows to full size */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
-   {
-      if (png_ptr->pass < 6)
-         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
-            png_ptr->transformations);
-
-    switch (png_ptr->pass)
-    {
-         case 0:
-         {
-            int i;
-            for (i = 0; i < 8 && png_ptr->pass == 0; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
-            }
-
-            if (png_ptr->pass == 2) /* Pass 1 might be empty */
-            {
-               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            if (png_ptr->pass == 4 && png_ptr->height <= 4)
-            {
-               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            if (png_ptr->pass == 6 && png_ptr->height <= 4)
-            {
-                png_push_have_row(png_ptr, NULL);
-                png_read_push_finish_row(png_ptr);
-            }
-
-            break;
-         }
-
-         case 1:
-         {
-            int i;
-            for (i = 0; i < 8 && png_ptr->pass == 1; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 2) /* Skip top 4 generated rows */
-            {
-               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            break;
-         }
-
-         case 2:
-         {
-            int i;
-
-            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
-            {
-               png_push_have_row(png_ptr, NULL);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 4) /* Pass 3 might be empty */
-            {
-               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            break;
-         }
-
-         case 3:
-         {
-            int i;
-
-            for (i = 0; i < 4 && png_ptr->pass == 3; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 4) /* Skip top two generated rows */
-            {
-               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-               {
-                  png_push_have_row(png_ptr, NULL);
-                  png_read_push_finish_row(png_ptr);
-               }
-            }
-
-            break;
-         }
-
-         case 4:
-         {
-            int i;
-
-            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
-            {
-               png_push_have_row(png_ptr, NULL);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 6) /* Pass 5 might be empty */
-            {
-               png_push_have_row(png_ptr, NULL);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            break;
-         }
-
-         case 5:
-         {
-            int i;
-
-            for (i = 0; i < 2 && png_ptr->pass == 5; i++)
-            {
-               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            if (png_ptr->pass == 6) /* Skip top generated row */
-            {
-               png_push_have_row(png_ptr, NULL);
-               png_read_push_finish_row(png_ptr);
-            }
-
-            break;
-         }
-
-         default:
-         case 6:
-         {
-            png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-            png_read_push_finish_row(png_ptr);
-
-            if (png_ptr->pass != 6)
-               break;
-
-            png_push_have_row(png_ptr, NULL);
-            png_read_push_finish_row(png_ptr);
-         }
-      }
-   }
-   else
-#endif
-   {
-      png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-      png_read_push_finish_row(png_ptr);
-   }
-}
-
-void /* PRIVATE */
-png_read_push_finish_row(png_structp png_ptr)
-{
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
-   /* Start of interlace block */
-   static PNG_CONST png_byte FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
-
-   /* Offset to next interlace block */
-   static PNG_CONST png_byte FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
-
-   /* Start of interlace block in the y direction */
-   static PNG_CONST png_byte FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
-
-   /* Offset to next interlace block in the y direction */
-   static PNG_CONST png_byte FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
-
-   /* Height of interlace block.  This is not currently used - if you need
-    * it, uncomment it here and in png.h
-   static PNG_CONST png_byte FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
-   */
-#endif
-
-   png_ptr->row_number++;
-   if (png_ptr->row_number < png_ptr->num_rows)
-      return;
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   if (png_ptr->interlaced)
-   {
-      png_ptr->row_number = 0;
-      png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
-
-      do
-      {
-         png_ptr->pass++;
-         if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
-             (png_ptr->pass == 3 && png_ptr->width < 3) ||
-             (png_ptr->pass == 5 && png_ptr->width < 2))
-            png_ptr->pass++;
-
-         if (png_ptr->pass > 7)
-            png_ptr->pass--;
-
-         if (png_ptr->pass >= 7)
-            break;
-
-         png_ptr->iwidth = (png_ptr->width +
-             png_pass_inc[png_ptr->pass] - 1 -
-             png_pass_start[png_ptr->pass]) /
-             png_pass_inc[png_ptr->pass];
-
-         if (png_ptr->transformations & PNG_INTERLACE)
-            break;
-
-         png_ptr->num_rows = (png_ptr->height +
-             png_pass_yinc[png_ptr->pass] - 1 -
-             png_pass_ystart[png_ptr->pass]) /
-             png_pass_yinc[png_ptr->pass];
-
-      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
-   }
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-}
-
-void /* PRIVATE */
-png_push_have_info(png_structp png_ptr, png_infop info_ptr)
-{
-   if (png_ptr->info_fn != NULL)
-      (*(png_ptr->info_fn))(png_ptr, info_ptr);
-}
-
-void /* PRIVATE */
-png_push_have_end(png_structp png_ptr, png_infop info_ptr)
-{
-   if (png_ptr->end_fn != NULL)
-      (*(png_ptr->end_fn))(png_ptr, info_ptr);
-}
-
-void /* PRIVATE */
-png_push_have_row(png_structp png_ptr, png_bytep row)
-{
-   if (png_ptr->row_fn != NULL)
-      (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
-         (int)png_ptr->pass);
-}
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-void PNGAPI
-png_progressive_combine_row (png_structp png_ptr, png_bytep old_row,
-    png_const_bytep new_row)
-{
-   if (png_ptr == NULL)
-      return;
-
-   /* new_row is a flag here - if it is NULL then the app callback was called
-    * from an empty row (see the calls to png_struct::row_fn below), otherwise
-    * it must be png_ptr->row_buf+1
-    */
-   if (new_row != NULL)
-      png_combine_row(png_ptr, old_row, 1/*display*/);
-}
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-
-void PNGAPI
-png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
-    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
-    png_progressive_end_ptr end_fn)
-{
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->info_fn = info_fn;
-   png_ptr->row_fn = row_fn;
-   png_ptr->end_fn = end_fn;
-
-   png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
-}
-
-png_voidp PNGAPI
-png_get_progressive_ptr(png_const_structp png_ptr)
-{
-   if (png_ptr == NULL)
-      return (NULL);
-
-   return png_ptr->io_ptr;
-}
-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
diff --git a/extern/libpng/include/pngpriv.h b/extern/libpng/include/pngpriv.h
deleted file mode 100644
index e76a57975f..0000000000
--- a/extern/libpng/include/pngpriv.h
+++ /dev/null
@@ -1,1677 +0,0 @@
-
-/* pngpriv.h - private declarations for use inside libpng
- *
- * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * Last changed in libpng 1.5.10 [March 29, 2012]
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-/* The symbols declared in this file (including the functions declared
- * as PNG_EXTERN) are PRIVATE.  They are not part of the libpng public
- * interface, and are not recommended for use by regular applications.
- * Some of them may become public in the future; others may stay private,
- * change in an incompatible way, or even disappear.
- * Although the libpng users are not forbidden to include this header,
- * they should be well aware of the issues that may arise from doing so.
- */
-
-#ifndef PNGPRIV_H
-#define PNGPRIV_H
-
-/* Feature Test Macros.  The following are defined here to ensure that correctly
- * implemented libraries reveal the APIs libpng needs to build and hide those
- * that are not needed and potentially damaging to the compilation.
- *
- * Feature Test Macros must be defined before any system header is included (see
- * POSIX 1003.1 2.8.2 "POSIX Symbols."
- *
- * These macros only have an effect if the operating system supports either
- * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
- * Windows/Visual Studio) there is no effect; the OS specific tests below are
- * still required (as of 2011-05-02.)
- */
-#define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
-
-/* This is required for the definition of abort(), used as a last ditch
- * error handler when all else fails.
- */
-#include <stdlib.h>
-
-/* This is used to find 'offsetof', used below for alignment tests. */
-#include <stddef.h>
-
-#define PNGLIB_BUILD /*libpng is being built, not used*/
-
-#ifdef PNG_USER_CONFIG
-#  include "pngusr.h"
-   /* These should have been defined in pngusr.h */
-#  ifndef PNG_USER_PRIVATEBUILD
-#    define PNG_USER_PRIVATEBUILD "Custom libpng build"
-#  endif
-#  ifndef PNG_USER_DLLFNAME_POSTFIX
-#    define PNG_USER_DLLFNAME_POSTFIX "Cb"
-#  endif
-#endif
-
-/* Is this a build of a DLL where compilation of the object modules requires
- * different preprocessor settings to those required for a simple library?  If
- * so PNG_BUILD_DLL must be set.
- *
- * If libpng is used inside a DLL but that DLL does not export the libpng APIs
- * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
- * static library of libpng then link the DLL against that.
- */
-#ifndef PNG_BUILD_DLL
-#  ifdef DLL_EXPORT
-      /* This is set by libtool when files are compiled for a DLL; libtool
-       * always compiles twice, even on systems where it isn't necessary.  Set
-       * PNG_BUILD_DLL in case it is necessary:
-       */
-#     define PNG_BUILD_DLL
-#  else
-#     ifdef _WINDLL
-         /* This is set by the Microsoft Visual Studio IDE in projects that
-          * build a DLL.  It can't easily be removed from those projects (it
-          * isn't visible in the Visual Studio UI) so it is a fairly reliable
-          * indication that PNG_IMPEXP needs to be set to the DLL export
-          * attributes.
-          */
-#        define PNG_BUILD_DLL
-#     else
-#        ifdef __DLL__
-            /* This is set by the Borland C system when compiling for a DLL
-             * (as above.)
-             */
-#           define PNG_BUILD_DLL
-#        else
-            /* Add additional compiler cases here. */
-#        endif
-#     endif
-#  endif
-#endif /* Setting PNG_BUILD_DLL if required */
-
-/* See pngconf.h for more details: the builder of the library may set this on
- * the command line to the right thing for the specific compilation system or it
- * may be automagically set above (at present we know of no system where it does
- * need to be set on the command line.)
- *
- * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
- * setting it to the "import" setting for a DLL build.
- */
-#ifndef PNG_IMPEXP
-#  ifdef PNG_BUILD_DLL
-#     define PNG_IMPEXP PNG_DLL_EXPORT
-#  else
-      /* Not building a DLL, or the DLL doesn't require specific export
-       * definitions.
-       */
-#     define PNG_IMPEXP
-#  endif
-#endif
-
-/* No warnings for private or deprecated functions in the build: */
-#ifndef PNG_DEPRECATED
-#  define PNG_DEPRECATED
-#endif
-#ifndef PNG_PRIVATE
-#  define PNG_PRIVATE
-#endif
-
-#include "png.h"
-#include "pnginfo.h"
-#include "pngstruct.h"
-
-/* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
-#ifndef PNG_DLL_EXPORT
-#  define PNG_DLL_EXPORT
-#endif
-
-/* SECURITY and SAFETY:
- *
- * By default libpng is built without any internal limits on image size,
- * individual heap (png_malloc) allocations or the total amount of memory used.
- * If PNG_SAFE_LIMITS_SUPPORTED is defined, however, the limits below are used
- * (unless individually overridden).  These limits are believed to be fairly
- * safe, but builders of secure systems should verify the values against the
- * real system capabilities.
- */
-
-#ifdef PNG_SAFE_LIMITS_SUPPORTED
-   /* 'safe' limits */
-#  ifndef PNG_USER_WIDTH_MAX
-#     define PNG_USER_WIDTH_MAX 1000000
-#  endif
-#  ifndef PNG_USER_HEIGHT_MAX
-#     define PNG_USER_HEIGHT_MAX 1000000
-#  endif
-#  ifndef PNG_USER_CHUNK_CACHE_MAX
-#     define PNG_USER_CHUNK_CACHE_MAX 128
-#  endif
-#  ifndef PNG_USER_CHUNK_MALLOC_MAX
-#     define PNG_USER_CHUNK_MALLOC_MAX 8000000
-#  endif
-#else
-   /* values for no limits */
-#  ifndef PNG_USER_WIDTH_MAX
-#     define PNG_USER_WIDTH_MAX 0x7fffffff
-#  endif
-#  ifndef PNG_USER_HEIGHT_MAX
-#     define PNG_USER_HEIGHT_MAX 0x7fffffff
-#  endif
-#  ifndef PNG_USER_CHUNK_CACHE_MAX
-#     define PNG_USER_CHUNK_CACHE_MAX 0
-#  endif
-#  ifndef PNG_USER_CHUNK_MALLOC_MAX
-#     define PNG_USER_CHUNK_MALLOC_MAX 0
-#  endif
-#endif
-
-/* This is used for 16 bit gamma tables - only the top level pointers are const,
- * this could be changed:
- */
-typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
-
-/* Added at libpng-1.2.9 */
-/* Moved to pngpriv.h at libpng-1.5.0 */
-
-/* config.h is created by and PNG_CONFIGURE_LIBPNG is set by the "configure"
- * script.  We may need it here to get the correct configuration on things
- * like limits.
- */
-#ifdef PNG_CONFIGURE_LIBPNG
-#  ifdef HAVE_CONFIG_H
-#    include "config.h"
-#  endif
-#endif
-
-/* Moved to pngpriv.h at libpng-1.5.0 */
-/* NOTE: some of these may have been used in external applications as
- * these definitions were exposed in pngconf.h prior to 1.5.
- */
-
-/* If you are running on a machine where you cannot allocate more
- * than 64K of memory at once, uncomment this.  While libpng will not
- * normally need that much memory in a chunk (unless you load up a very
- * large file), zlib needs to know how big of a chunk it can use, and
- * libpng thus makes sure to check any memory allocation to verify it
- * will fit into memory.
- *
- * zlib provides 'MAXSEG_64K' which, if defined, indicates the
- * same limit and pngconf.h (already included) sets the limit
- * if certain operating systems are detected.
- */
-#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
-#  define PNG_MAX_MALLOC_64K
-#endif
-
-#ifndef PNG_UNUSED
-/* Unused formal parameter warnings are silenced using the following macro
- * which is expected to have no bad effects on performance (optimizing
- * compilers will probably remove it entirely).  Note that if you replace
- * it with something other than whitespace, you must include the terminating
- * semicolon.
- */
-#  define PNG_UNUSED(param) (void)param;
-#endif
-
-/* Just a little check that someone hasn't tried to define something
- * contradictory.
- */
-#if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
-#  undef PNG_ZBUF_SIZE
-#  define PNG_ZBUF_SIZE 65536L
-#endif
-
-/* PNG_STATIC is used to mark internal file scope functions if they need to be
- * accessed for implementation tests (see the code in tests/?*).
- */
-#ifndef PNG_STATIC
-#   define PNG_STATIC static
-#endif
-
-/* C99 restrict is used where possible, to do this 'restrict' is defined as
- * empty if we can't be sure it is supported.  configure builds have already
- * done this work.
- */
-#ifdef PNG_CONFIGURE_LIBPNG
-#  define PNG_RESTRICT restrict
-#else
-   /* Modern compilers support restrict, but assume not for anything not
-    * recognized here:
-    */
-#  if defined __GNUC__ || defined _MSC_VER || defined __WATCOMC__
-#     define PNG_RESTRICT restrict
-#  else
-#     define PNG_RESTRICT
-#  endif
-#endif
-
-/* If warnings or errors are turned off the code is disabled or redirected here.
- * From 1.5.4 functions have been added to allow very limited formatting of
- * error and warning messages - this code will also be disabled here.
- */
-#ifdef PNG_WARNINGS_SUPPORTED
-#  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
-#else
-#  define png_warning(s1,s2) ((void)(s1))
-#  define png_chunk_warning(s1,s2) ((void)(s1))
-#  define png_warning_parameter(p,number,string) ((void)0)
-#  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
-#  define png_warning_parameter_signed(p,number,format,value) ((void)0)
-#  define png_formatted_warning(pp,p,message) ((void)(pp))
-#  define PNG_WARNING_PARAMETERS(p)
-#endif
-#ifndef PNG_ERROR_TEXT_SUPPORTED
-#  define png_error(s1,s2) png_err(s1)
-#  define png_chunk_error(s1,s2) png_err(s1)
-#  define png_fixed_error(s1,s2) png_err(s1)
-#endif
-
-/* C allows up-casts from (void*) to any pointer and (const void*) to any
- * pointer to a const object.  C++ regards this as a type error and requires an
- * explicit, static, cast and provides the static_cast<> rune to ensure that
- * const is not cast away.
- */
-#ifdef __cplusplus
-#  define png_voidcast(type, value) static_cast<type>(value)
-#else
-#  define png_voidcast(type, value) (value)
-#endif /* __cplusplus */
-
-#ifndef PNG_EXTERN
-/* The functions exported by PNG_EXTERN are internal functions, which
- * aren't usually used outside the library (as far as I know), so it is
- * debatable if they should be exported at all.  In the future, when it
- * is possible to have run-time registry of chunk-handling functions,
- * some of these might be made available again.
- *
- * 1.5.7: turned the use of 'extern' back on, since it is localized to pngpriv.h
- * it should be safe now (it is unclear why it was turned off.)
- */
-#  define PNG_EXTERN extern
-#endif
-
-/* Some fixed point APIs are still required even if not exported because
- * they get used by the corresponding floating point APIs.  This magic
- * deals with this:
- */
-#ifdef PNG_FIXED_POINT_SUPPORTED
-#  define PNGFAPI PNGAPI
-#else
-#  define PNGFAPI /* PRIVATE */
-#endif
-
-/* Other defines specific to compilers can go here.  Try to keep
- * them inside an appropriate ifdef/endif pair for portability.
- */
-#if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
-    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
-   /* png.c requires the following ANSI-C constants if the conversion of
-    * floating point to ASCII is implemented therein:
-    *
-    *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
-    *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
-    *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
-    */
-#  include <float.h>
-
-#  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
-    defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
-     /* We need to check that <math.h> hasn't already been included earlier
-      * as it seems it doesn't agree with <fp.h>, yet we should really use
-      * <fp.h> if possible.
-      */
-#    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
-#      include <fp.h>
-#    endif
-#  else
-#    include <math.h>
-#  endif
-#  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
-     /* Amiga SAS/C: We must include builtin FPU functions when compiling using
-      * MATH=68881
-      */
-#    include <m68881.h>
-#  endif
-#endif
-
-/* This provides the non-ANSI (far) memory allocation routines. */
-#if defined(__TURBOC__) && defined(__MSDOS__)
-#  include <mem.h>
-#  include <alloc.h>
-#endif
-
-#if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
-    defined(_WIN32) || defined(__WIN32__)
-#  include <windows.h>  /* defines _WINDOWS_ macro */
-#endif
-
-/* Moved here around 1.5.0beta36 from pngconf.h */
-/* Users may want to use these so they are not private.  Any library
- * functions that are passed far data must be model-independent.
- */
-
-/* Memory model/platform independent fns */
-#ifndef PNG_ABORT
-#  ifdef _WINDOWS_
-#    define PNG_ABORT() ExitProcess(0)
-#  else
-#    define PNG_ABORT() abort()
-#  endif
-#endif
-
-#ifdef USE_FAR_KEYWORD
-/* Use this to make far-to-near assignments */
-#  define CHECK   1
-#  define NOCHECK 0
-#  define CVT_PTR(ptr) (png_far_to_near(png_ptr,ptr,CHECK))
-#  define CVT_PTR_NOCHECK(ptr) (png_far_to_near(png_ptr,ptr,NOCHECK))
-#  define png_strlen  _fstrlen
-#  define png_memcmp  _fmemcmp    /* SJT: added */
-#  define png_memcpy  _fmemcpy
-#  define png_memset  _fmemset
-#else
-#  ifdef _WINDOWS_  /* Favor Windows over C runtime fns */
-#    define CVT_PTR(ptr)         (ptr)
-#    define CVT_PTR_NOCHECK(ptr) (ptr)
-#    define png_strlen  lstrlenA
-#    define png_memcmp  memcmp
-#    define png_memcpy  CopyMemory
-#    define png_memset  memset
-#  else
-#    define CVT_PTR(ptr)         (ptr)
-#    define CVT_PTR_NOCHECK(ptr) (ptr)
-#    define png_strlen  strlen
-#    define png_memcmp  memcmp      /* SJT: added */
-#    define png_memcpy  memcpy
-#    define png_memset  memset
-#  endif
-#endif
-
-/* These macros may need to be architecture dependent. */
-#define PNG_ALIGN_NONE   0 /* do not use data alignment */
-#define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
-#ifdef offsetof
-#  define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
-#else
-#  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
-#endif
-#define PNG_ALIGN_SIZE   3 /* use sizeof to determine alignment */
-
-#ifndef PNG_ALIGN_TYPE
-   /* Default to using aligned access optimizations and requiring alignment to a
-    * multiple of the data type size.  Override in a compiler specific fashion
-    * if necessary by inserting tests here:
-    */
-#  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
-#endif
-
-#if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
-   /* This is used because in some compiler implementations non-aligned
-    * structure members are supported, so the offsetof approach below fails.
-    * Set PNG_ALIGN_TO_SIZE=0 for compiler combinations where unaligned access
-    * is good for performance.  Do not do this unless you have tested the result
-    * and understand it.
-    */
-#  define png_alignof(type) (sizeof (type))
-#else
-#  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
-#     define png_alignof(type) offsetof(struct{char c; type t;}, t)
-#  else
-#     if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
-#        define png_alignof(type) (1)
-#     endif
-      /* Else leave png_alignof undefined to prevent use thereof */
-#  endif
-#endif
-
-/* This implicitly assumes alignment is always to a power of 2. */
-#ifdef png_alignof
-#  define png_isaligned(ptr, type)\
-   ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
-#else
-#  define png_isaligned(ptr, type) 0
-#endif
-
-/* End of memory model/platform independent support */
-/* End of 1.5.0beta36 move from pngconf.h */
-
-/* CONSTANTS and UTILITY MACROS
- * These are used internally by libpng and not exposed in the API
- */
-
-/* Various modes of operation.  Note that after an init, mode is set to
- * zero automatically when the structure is created.  Three of these
- * are defined in png.h because they need to be visible to applications
- * that call png_set_unknown_chunk().
- */
-/* #define PNG_HAVE_IHDR            0x01 (defined in png.h) */
-/* #define PNG_HAVE_PLTE            0x02 (defined in png.h) */
-#define PNG_HAVE_IDAT               0x04
-/* #define PNG_AFTER_IDAT           0x08 (defined in png.h) */
-#define PNG_HAVE_IEND               0x10
-#define PNG_HAVE_gAMA               0x20
-#define PNG_HAVE_cHRM               0x40
-#define PNG_HAVE_sRGB               0x80
-#define PNG_HAVE_CHUNK_HEADER      0x100
-#define PNG_WROTE_tIME             0x200
-#define PNG_WROTE_INFO_BEFORE_PLTE 0x400
-#define PNG_BACKGROUND_IS_GRAY     0x800
-#define PNG_HAVE_PNG_SIGNATURE    0x1000
-#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
-#define PNG_HAVE_iCCP             0x4000
-
-/* Flags for the transformations the PNG library does on the image data */
-#define PNG_BGR                 0x0001
-#define PNG_INTERLACE           0x0002
-#define PNG_PACK                0x0004
-#define PNG_SHIFT               0x0008
-#define PNG_SWAP_BYTES          0x0010
-#define PNG_INVERT_MONO         0x0020
-#define PNG_QUANTIZE            0x0040
-#define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
-#define PNG_BACKGROUND_EXPAND   0x0100
-#define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
-#define PNG_16_TO_8             0x0400     /* Becomes 'chop' in 1.5.4 */
-#define PNG_RGBA                0x0800
-#define PNG_EXPAND              0x1000
-#define PNG_GAMMA               0x2000
-#define PNG_GRAY_TO_RGB         0x4000
-#define PNG_FILLER              0x8000
-#define PNG_PACKSWAP           0x10000
-#define PNG_SWAP_ALPHA         0x20000
-#define PNG_STRIP_ALPHA        0x40000
-#define PNG_INVERT_ALPHA       0x80000
-#define PNG_USER_TRANSFORM    0x100000
-#define PNG_RGB_TO_GRAY_ERR   0x200000
-#define PNG_RGB_TO_GRAY_WARN  0x400000
-#define PNG_RGB_TO_GRAY       0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
-#define PNG_ENCODE_ALPHA      0x800000 /* Added to libpng-1.5.4 */
-#define PNG_ADD_ALPHA         0x1000000 /* Added to libpng-1.2.7 */
-#define PNG_EXPAND_tRNS       0x2000000 /* Added to libpng-1.2.9 */
-#define PNG_SCALE_16_TO_8     0x4000000 /* Added to libpng-1.5.4 */
-                       /*   0x8000000 unused */
-                       /*  0x10000000 unused */
-                       /*  0x20000000 unused */
-                       /*  0x40000000 unused */
-/* Flags for png_create_struct */
-#define PNG_STRUCT_PNG   0x0001
-#define PNG_STRUCT_INFO  0x0002
-
-/* Scaling factor for filter heuristic weighting calculations */
-#define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
-#define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
-
-/* Flags for the png_ptr->flags rather than declaring a byte for each one */
-#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
-#define PNG_FLAG_ZLIB_CUSTOM_LEVEL        0x0002
-#define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL    0x0004
-#define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS  0x0008
-#define PNG_FLAG_ZLIB_CUSTOM_METHOD       0x0010
-#define PNG_FLAG_ZLIB_FINISHED            0x0020
-#define PNG_FLAG_ROW_INIT                 0x0040
-#define PNG_FLAG_FILLER_AFTER             0x0080
-#define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
-#define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
-#define PNG_FLAG_CRC_CRITICAL_USE         0x0400
-#define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
-#define PNG_FLAG_ASSUME_sRGB              0x1000  /* Added to libpng-1.5.4 */
-#define PNG_FLAG_OPTIMIZE_ALPHA           0x2000  /* Added to libpng-1.5.4 */
-#define PNG_FLAG_DETECT_UNINITIALIZED     0x4000  /* Added to libpng-1.5.4 */
-#define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000
-#define PNG_FLAG_KEEP_UNSAFE_CHUNKS       0x10000
-#define PNG_FLAG_LIBRARY_MISMATCH         0x20000
-#define PNG_FLAG_STRIP_ERROR_NUMBERS      0x40000
-#define PNG_FLAG_STRIP_ERROR_TEXT         0x80000
-#define PNG_FLAG_MALLOC_NULL_MEM_OK       0x100000
-                                  /*      0x200000  unused */
-                                  /*      0x400000  unused */
-#define PNG_FLAG_BENIGN_ERRORS_WARN       0x800000  /* Added to libpng-1.4.0 */
-#define PNG_FLAG_ZTXT_CUSTOM_STRATEGY    0x1000000  /* 5 lines added */
-#define PNG_FLAG_ZTXT_CUSTOM_LEVEL       0x2000000  /* to libpng-1.5.4 */
-#define PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL   0x4000000
-#define PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS 0x8000000
-#define PNG_FLAG_ZTXT_CUSTOM_METHOD      0x10000000
-                                  /*     0x20000000  unused */
-                                  /*     0x40000000  unused */
-
-#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
-                                     PNG_FLAG_CRC_ANCILLARY_NOWARN)
-
-#define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
-                                     PNG_FLAG_CRC_CRITICAL_IGNORE)
-
-#define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
-                                     PNG_FLAG_CRC_CRITICAL_MASK)
-
-/* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
- * can handle at once.  This type need be no larger than 16 bits (so maximum of
- * 65535), this define allows us to discover how big it is, but limited by the
- * maximuum for png_size_t.  The value can be overriden in a library build
- * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
- * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
- * and may even improve performance on some systems (and degrade it on others.)
- */
-#ifndef ZLIB_IO_MAX
-#  define ZLIB_IO_MAX ((uInt)-1)
-#endif
-
-/* Save typing and make code easier to understand */
-
-#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
-   abs((int)((c1).green) - (int)((c2).green)) + \
-   abs((int)((c1).blue) - (int)((c2).blue)))
-
-/* Added to libpng-1.2.6 JB */
-#define PNG_ROWBYTES(pixel_bits, width) \
-    ((pixel_bits) >= 8 ? \
-    ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
-    (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
-
-/* PNG_OUT_OF_RANGE returns true if value is outside the range
- * ideal-delta..ideal+delta.  Each argument is evaluated twice.
- * "ideal" and "delta" should be constants, normally simple
- * integers, "value" a variable. Added to libpng-1.2.6 JB
- */
-#define PNG_OUT_OF_RANGE(value, ideal, delta) \
-   ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
-
-/* Conversions between fixed and floating point, only defined if
- * required (to make sure the code doesn't accidentally use float
- * when it is supposedly disabled.)
- */
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-/* The floating point conversion can't overflow, though it can and
- * does lose accuracy relative to the original fixed point value.
- * In practice this doesn't matter because png_fixed_point only
- * stores numbers with very low precision.  The png_ptr and s
- * arguments are unused by default but are there in case error
- * checking becomes a requirement.
- */
-#define png_float(png_ptr, fixed, s) (.00001 * (fixed))
-
-/* The fixed point conversion performs range checking and evaluates
- * its argument multiple times, so must be used with care.  The
- * range checking uses the PNG specification values for a signed
- * 32 bit fixed point value except that the values are deliberately
- * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
- * (2^31-1) * 100000). 's' is a string that describes the value being
- * converted.
- *
- * NOTE: this macro will raise a png_error if the range check fails,
- * therefore it is normally only appropriate to use this on values
- * that come from API calls or other sources where an out of range
- * error indicates a programming error, not a data error!
- *
- * NOTE: by default this is off - the macro is not used - because the
- * function call saves a lot of code.
- */
-#ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
-#define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
-    ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
-#else
-PNG_EXTERN png_fixed_point png_fixed PNGARG((png_structp png_ptr, double fp,
-   png_const_charp text));
-#endif
-#endif
-
-/* Constants for known chunk types.  If you need to add a chunk, define the name
- * here.  For historical reasons these constants have the form png_<name>; i.e.
- * the prefix is lower case.  Please use decimal values as the parameters to
- * match the ISO PNG specification and to avoid relying on the C locale
- * interpretation of character values.
- *
- * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
- * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
- * to be generated if required.
- *
- * PNG_32b correctly produces a value shifted by up to 24 bits, even on
- * architectures where (int) is only 16 bits.
- */
-#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
-#define PNG_CHUNK(b1,b2,b3,b4) \
-   (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
-
-#define png_IHDR PNG_CHUNK( 73,  72,  68,  82)
-#define png_IDAT PNG_CHUNK( 73,  68,  65,  84)
-#define png_IEND PNG_CHUNK( 73,  69,  78,  68)
-#define png_PLTE PNG_CHUNK( 80,  76,  84,  69)
-#define png_bKGD PNG_CHUNK( 98,  75,  71,  68)
-#define png_cHRM PNG_CHUNK( 99,  72,  82,  77)
-#define png_gAMA PNG_CHUNK(103,  65,  77,  65)
-#define png_hIST PNG_CHUNK(104,  73,  83,  84)
-#define png_iCCP PNG_CHUNK(105,  67,  67,  80)
-#define png_iTXt PNG_CHUNK(105,  84,  88, 116)
-#define png_oFFs PNG_CHUNK(111,  70,  70, 115)
-#define png_pCAL PNG_CHUNK(112,  67,  65,  76)
-#define png_sCAL PNG_CHUNK(115,  67,  65,  76)
-#define png_pHYs PNG_CHUNK(112,  72,  89, 115)
-#define png_sBIT PNG_CHUNK(115,  66,  73,  84)
-#define png_sPLT PNG_CHUNK(115,  80,  76,  84)
-#define png_sRGB PNG_CHUNK(115,  82,  71,  66)
-#define png_sTER PNG_CHUNK(115,  84,  69,  82)
-#define png_tEXt PNG_CHUNK(116,  69,  88, 116)
-#define png_tIME PNG_CHUNK(116,  73,  77,  69)
-#define png_tRNS PNG_CHUNK(116,  82,  78,  83)
-#define png_zTXt PNG_CHUNK(122,  84,  88, 116)
-
-/* The following will work on (signed char*) strings, whereas the get_uint_32
- * macro will fail on top-bit-set values because of the sign extension.
- */
-#define PNG_CHUNK_FROM_STRING(s)\
-   PNG_CHUNK(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
-
-/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
- * signed and the argument is a (char[])  This macro will fail miserably on
- * systems where (char) is more than 8 bits.
- */
-#define PNG_STRING_FROM_CHUNK(s,c)\
-   (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
-   ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
-
-/* Do the same but terminate with a null character. */
-#define PNG_CSTRING_FROM_CHUNK(s,c)\
-   (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
-
-/* Test on flag values as defined in the spec (section 5.4): */
-#define PNG_CHUNK_ANCILLIARY(c)   (1 & ((c) >> 29))
-#define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLIARY(c))
-#define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
-#define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
-#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
-
-/* Gamma values (new at libpng-1.5.4): */
-#define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
-#define PNG_GAMMA_MAC_INVERSE 65909
-#define PNG_GAMMA_sRGB_INVERSE 45455
-
-
-/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-
-/* These functions are used internally in the code.  They generally
- * shouldn't be used unless you are writing code to add or replace some
- * functionality in libpng.  More information about most functions can
- * be found in the files where the functions are located.
- */
-
-/* Check the user version string for compatibility, returns false if the version
- * numbers aren't compatible.
- */
-PNG_EXTERN int png_user_version_check(png_structp png_ptr,
-   png_const_charp user_png_ver);
-
-/* Allocate memory for an internal libpng struct */
-PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct,PNGARG((int type)),
-   PNG_ALLOCATED);
-
-/* Free memory from internal libpng struct */
-PNG_EXTERN void png_destroy_struct PNGARG((png_voidp struct_ptr));
-
-PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct_2,
-   PNGARG((int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)),
-   PNG_ALLOCATED);
-PNG_EXTERN void png_destroy_struct_2 PNGARG((png_voidp struct_ptr,
-    png_free_ptr free_fn, png_voidp mem_ptr));
-
-/* Free any memory that info_ptr points to and reset struct. */
-PNG_EXTERN void png_info_destroy PNGARG((png_structp png_ptr,
-    png_infop info_ptr));
-
-/* Function to allocate memory for zlib.  PNGAPI is disallowed. */
-PNG_EXTERN PNG_FUNCTION(voidpf,png_zalloc,PNGARG((voidpf png_ptr, uInt items,
-   uInt size)),PNG_ALLOCATED);
-
-/* Function to free memory for zlib.  PNGAPI is disallowed. */
-PNG_EXTERN void png_zfree PNGARG((voidpf png_ptr, voidpf ptr));
-
-/* Next four functions are used internally as callbacks.  PNGCBAPI is required
- * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
- * PNGCBAPI at 1.5.0
- */
-
-PNG_EXTERN void PNGCBAPI png_default_read_data PNGARG((png_structp png_ptr,
-    png_bytep data, png_size_t length));
-
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-PNG_EXTERN void PNGCBAPI png_push_fill_buffer PNGARG((png_structp png_ptr,
-    png_bytep buffer, png_size_t length));
-#endif
-
-PNG_EXTERN void PNGCBAPI png_default_write_data PNGARG((png_structp png_ptr,
-    png_bytep data, png_size_t length));
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-#  ifdef PNG_STDIO_SUPPORTED
-PNG_EXTERN void PNGCBAPI png_default_flush PNGARG((png_structp png_ptr));
-#  endif
-#endif
-
-/* Reset the CRC variable */
-PNG_EXTERN void png_reset_crc PNGARG((png_structp png_ptr));
-
-/* Write the "data" buffer to whatever output you are using */
-PNG_EXTERN void png_write_data PNGARG((png_structp png_ptr,
-    png_const_bytep data, png_size_t length));
-
-/* Read and check the PNG file signature */
-PNG_EXTERN void png_read_sig PNGARG((png_structp png_ptr, png_infop info_ptr));
-
-/* Read the chunk header (length + type name) */
-PNG_EXTERN png_uint_32 png_read_chunk_header PNGARG((png_structp png_ptr));
-
-/* Read data from whatever input you are using into the "data" buffer */
-PNG_EXTERN void png_read_data PNGARG((png_structp png_ptr, png_bytep data,
-    png_size_t length));
-
-/* Read bytes into buf, and update png_ptr->crc */
-PNG_EXTERN void png_crc_read PNGARG((png_structp png_ptr, png_bytep buf,
-    png_size_t length));
-
-/* Decompress data in a chunk that uses compression */
-#if defined(PNG_READ_COMPRESSED_TEXT_SUPPORTED)
-PNG_EXTERN void png_decompress_chunk PNGARG((png_structp png_ptr,
-    int comp_type, png_size_t chunklength, png_size_t prefix_length,
-    png_size_t *data_length));
-#endif
-
-/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
-PNG_EXTERN int png_crc_finish PNGARG((png_structp png_ptr, png_uint_32 skip));
-
-/* Read the CRC from the file and compare it to the libpng calculated CRC */
-PNG_EXTERN int png_crc_error PNGARG((png_structp png_ptr));
-
-/* Calculate the CRC over a section of data.  Note that we are only
- * passing a maximum of 64K on systems that have this as a memory limit,
- * since this is the maximum buffer size we can specify.
- */
-PNG_EXTERN void png_calculate_crc PNGARG((png_structp png_ptr,
-    png_const_bytep ptr, png_size_t length));
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-PNG_EXTERN void png_flush PNGARG((png_structp png_ptr));
-#endif
-
-/* Write various chunks */
-
-/* Write the IHDR chunk, and update the png_struct with the necessary
- * information.
- */
-PNG_EXTERN void png_write_IHDR PNGARG((png_structp png_ptr, png_uint_32 width,
-    png_uint_32 height,
-    int bit_depth, int color_type, int compression_method, int filter_method,
-    int interlace_method));
-
-PNG_EXTERN void png_write_PLTE PNGARG((png_structp png_ptr,
-    png_const_colorp palette, png_uint_32 num_pal));
-
-PNG_EXTERN void png_write_IDAT PNGARG((png_structp png_ptr, png_bytep data,
-    png_size_t length));
-
-PNG_EXTERN void png_write_IEND PNGARG((png_structp png_ptr));
-
-#ifdef PNG_WRITE_gAMA_SUPPORTED
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-PNG_EXTERN void png_write_gAMA PNGARG((png_structp png_ptr, double file_gamma));
-#  endif
-#  ifdef PNG_FIXED_POINT_SUPPORTED
-PNG_EXTERN void png_write_gAMA_fixed PNGARG((png_structp png_ptr,
-    png_fixed_point file_gamma));
-#  endif
-#endif
-
-#ifdef PNG_WRITE_sBIT_SUPPORTED
-PNG_EXTERN void png_write_sBIT PNGARG((png_structp png_ptr,
-    png_const_color_8p sbit, int color_type));
-#endif
-
-#ifdef PNG_WRITE_cHRM_SUPPORTED
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-PNG_EXTERN void png_write_cHRM PNGARG((png_structp png_ptr,
-    double white_x, double white_y,
-    double red_x, double red_y, double green_x, double green_y,
-    double blue_x, double blue_y));
-#  endif
-PNG_EXTERN void png_write_cHRM_fixed PNGARG((png_structp png_ptr,
-    png_fixed_point int_white_x, png_fixed_point int_white_y,
-    png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
-    int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
-    png_fixed_point int_blue_y));
-#endif
-
-#ifdef PNG_WRITE_sRGB_SUPPORTED
-PNG_EXTERN void png_write_sRGB PNGARG((png_structp png_ptr,
-    int intent));
-#endif
-
-#ifdef PNG_WRITE_iCCP_SUPPORTED
-PNG_EXTERN void png_write_iCCP PNGARG((png_structp png_ptr,
-    png_const_charp name, int compression_type,
-    png_const_charp profile, int proflen));
-   /* Note to maintainer: profile should be png_bytep */
-#endif
-
-#ifdef PNG_WRITE_sPLT_SUPPORTED
-PNG_EXTERN void png_write_sPLT PNGARG((png_structp png_ptr,
-    png_const_sPLT_tp palette));
-#endif
-
-#ifdef PNG_WRITE_tRNS_SUPPORTED
-PNG_EXTERN void png_write_tRNS PNGARG((png_structp png_ptr,
-    png_const_bytep trans, png_const_color_16p values, int number,
-    int color_type));
-#endif
-
-#ifdef PNG_WRITE_bKGD_SUPPORTED
-PNG_EXTERN void png_write_bKGD PNGARG((png_structp png_ptr,
-    png_const_color_16p values, int color_type));
-#endif
-
-#ifdef PNG_WRITE_hIST_SUPPORTED
-PNG_EXTERN void png_write_hIST PNGARG((png_structp png_ptr,
-    png_const_uint_16p hist, int num_hist));
-#endif
-
-/* Chunks that have keywords */
-#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
-    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
-PNG_EXTERN png_size_t png_check_keyword PNGARG((png_structp png_ptr,
-    png_const_charp key, png_charpp new_key));
-#endif
-
-#ifdef PNG_WRITE_tEXt_SUPPORTED
-PNG_EXTERN void png_write_tEXt PNGARG((png_structp png_ptr, png_const_charp key,
-    png_const_charp text, png_size_t text_len));
-#endif
-
-#ifdef PNG_WRITE_zTXt_SUPPORTED
-PNG_EXTERN void png_write_zTXt PNGARG((png_structp png_ptr, png_const_charp key,
-    png_const_charp text, png_size_t text_len, int compression));
-#endif
-
-#ifdef PNG_WRITE_iTXt_SUPPORTED
-PNG_EXTERN void png_write_iTXt PNGARG((png_structp png_ptr,
-    int compression, png_const_charp key, png_const_charp lang,
-    png_const_charp lang_key, png_const_charp text));
-#endif
-
-#ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
-PNG_EXTERN int png_set_text_2 PNGARG((png_structp png_ptr,
-    png_infop info_ptr, png_const_textp text_ptr, int num_text));
-#endif
-
-#ifdef PNG_WRITE_oFFs_SUPPORTED
-PNG_EXTERN void png_write_oFFs PNGARG((png_structp png_ptr,
-    png_int_32 x_offset, png_int_32 y_offset, int unit_type));
-#endif
-
-#ifdef PNG_WRITE_pCAL_SUPPORTED
-PNG_EXTERN void png_write_pCAL PNGARG((png_structp png_ptr, png_charp purpose,
-    png_int_32 X0, png_int_32 X1, int type, int nparams,
-    png_const_charp units, png_charpp params));
-#endif
-
-#ifdef PNG_WRITE_pHYs_SUPPORTED
-PNG_EXTERN void png_write_pHYs PNGARG((png_structp png_ptr,
-    png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
-    int unit_type));
-#endif
-
-#ifdef PNG_WRITE_tIME_SUPPORTED
-PNG_EXTERN void png_write_tIME PNGARG((png_structp png_ptr,
-    png_const_timep mod_time));
-#endif
-
-#ifdef PNG_WRITE_sCAL_SUPPORTED
-PNG_EXTERN void png_write_sCAL_s PNGARG((png_structp png_ptr,
-    int unit, png_const_charp width, png_const_charp height));
-#endif
-
-/* Called when finished processing a row of data */
-PNG_EXTERN void png_write_finish_row PNGARG((png_structp png_ptr));
-
-/* Internal use only.   Called before first row of data */
-PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr));
-
-/* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
- * array of png_ptr->width pixels.  If the image is not interlaced or this
- * is the final pass this just does a png_memcpy, otherwise the "display" flag
- * is used to determine whether to copy pixels that are not in the current pass.
- *
- * Because 'png_do_read_interlace' (below) replicates pixels this allows this
- * function to achieve the documented 'blocky' appearance during interlaced read
- * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
- * are not changed if they are not in the current pass, when display is 0.
- *
- * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
- *
- * The API always reads from the png_struct row buffer and always assumes that
- * it is full width (png_do_read_interlace has already been called.)
- *
- * This function is only ever used to write to row buffers provided by the
- * caller of the relevant libpng API and the row must have already been
- * transformed by the read transformations.
- *
- * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
- * bitmasks for use within the code, otherwise runtime generated masks are used.
- * The default is compile time masks.
- */
-#ifndef PNG_USE_COMPILE_TIME_MASKS
-#  define PNG_USE_COMPILE_TIME_MASKS 1
-#endif
-PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,
-    int display));
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-/* Expand an interlaced row: the 'row_info' describes the pass data that has
- * been read in and must correspond to the pixels in 'row', the pixels are
- * expanded (moved apart) in 'row' to match the final layout, when doing this
- * the pixels are *replicated* to the intervening space.  This is essential for
- * the correct operation of png_combine_row, above.
- */
-PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,
-    png_bytep row, int pass, png_uint_32 transformations));
-#endif
-
-/* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-/* Grab pixels out of a row for an interlaced pass */
-PNG_EXTERN void png_do_write_interlace PNGARG((png_row_infop row_info,
-    png_bytep row, int pass));
-#endif
-
-/* Unfilter a row: check the filter value before calling this, there is no point
- * calling it for PNG_FILTER_VALUE_NONE.
- */
-PNG_EXTERN void png_read_filter_row PNGARG((png_structp pp, png_row_infop row_info,
-    png_bytep row, png_const_bytep prev_row, int filter));
-
-PNG_EXTERN void png_read_filter_row_up_neon PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_bytep prev_row));
-PNG_EXTERN void png_read_filter_row_sub3_neon PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_bytep prev_row));
-PNG_EXTERN void png_read_filter_row_sub4_neon PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_bytep prev_row));
-PNG_EXTERN void png_read_filter_row_avg3_neon PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_bytep prev_row));
-PNG_EXTERN void png_read_filter_row_avg4_neon PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_bytep prev_row));
-PNG_EXTERN void png_read_filter_row_paeth3_neon PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_bytep prev_row));
-PNG_EXTERN void png_read_filter_row_paeth4_neon PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_bytep prev_row));
-
-/* Choose the best filter to use and filter the row data */
-PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,
-    png_row_infop row_info));
-
-/* Finish a row while reading, dealing with interlacing passes, etc. */
-PNG_EXTERN void png_read_finish_row PNGARG((png_structp png_ptr));
-
-/* Initialize the row buffers, etc. */
-PNG_EXTERN void png_read_start_row PNGARG((png_structp png_ptr));
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-/* Optional call to update the users info structure */
-PNG_EXTERN void png_read_transform_info PNGARG((png_structp png_ptr,
-    png_infop info_ptr));
-#endif
-
-/* These are the functions that do the transformations */
-#ifdef PNG_READ_FILLER_SUPPORTED
-PNG_EXTERN void png_do_read_filler PNGARG((png_row_infop row_info,
-    png_bytep row, png_uint_32 filler, png_uint_32 flags));
-#endif
-
-#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
-PNG_EXTERN void png_do_read_swap_alpha PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-PNG_EXTERN void png_do_write_swap_alpha PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-PNG_EXTERN void png_do_read_invert_alpha PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-PNG_EXTERN void png_do_write_invert_alpha PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
-    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
-PNG_EXTERN void png_do_strip_channel PNGARG((png_row_infop row_info,
-    png_bytep row, int at_start));
-#endif
-
-#ifdef PNG_16BIT_SUPPORTED
-#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
-PNG_EXTERN void png_do_swap PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-#endif
-
-#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
-    defined(PNG_WRITE_PACKSWAP_SUPPORTED)
-PNG_EXTERN void png_do_packswap PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-PNG_EXTERN int png_do_rgb_to_gray PNGARG((png_structp png_ptr,
-    png_row_infop row_info, png_bytep row));
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-PNG_EXTERN void png_do_gray_to_rgb PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_READ_PACK_SUPPORTED
-PNG_EXTERN void png_do_unpack PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_READ_SHIFT_SUPPORTED
-PNG_EXTERN void png_do_unshift PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_color_8p sig_bits));
-#endif
-
-#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
-PNG_EXTERN void png_do_invert PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-PNG_EXTERN void png_do_scale_16_to_8 PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-PNG_EXTERN void png_do_quantize PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_bytep palette_lookup,
-    png_const_bytep quantize_lookup));
-
-#  ifdef PNG_CORRECT_PALETTE_SUPPORTED
-PNG_EXTERN void png_correct_palette PNGARG((png_structp png_ptr,
-    png_colorp palette, int num_palette));
-#  endif
-#endif
-
-#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
-PNG_EXTERN void png_do_bgr PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-#ifdef PNG_WRITE_PACK_SUPPORTED
-PNG_EXTERN void png_do_pack PNGARG((png_row_infop row_info,
-   png_bytep row, png_uint_32 bit_depth));
-#endif
-
-#ifdef PNG_WRITE_SHIFT_SUPPORTED
-PNG_EXTERN void png_do_shift PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_color_8p bit_depth));
-#endif
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-PNG_EXTERN void png_do_compose PNGARG((png_row_infop row_info,
-    png_bytep row, png_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-PNG_EXTERN void png_do_gamma PNGARG((png_row_infop row_info,
-    png_bytep row, png_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-PNG_EXTERN void png_do_encode_alpha PNGARG((png_row_infop row_info,
-   png_bytep row, png_structp png_ptr));
-#endif
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-PNG_EXTERN void png_do_expand_palette PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_colorp palette, png_const_bytep trans,
-    int num_trans));
-PNG_EXTERN void png_do_expand PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_color_16p trans_color));
-#endif
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-PNG_EXTERN void png_do_expand_16 PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-/* The following decodes the appropriate chunks, and does error correction,
- * then calls the appropriate callback for the chunk if it is valid.
- */
-
-/* Decode the IHDR chunk */
-PNG_EXTERN void png_handle_IHDR PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-PNG_EXTERN void png_handle_PLTE PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-PNG_EXTERN void png_handle_IEND PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-
-#ifdef PNG_READ_bKGD_SUPPORTED
-PNG_EXTERN void png_handle_bKGD PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_cHRM_SUPPORTED
-PNG_EXTERN void png_handle_cHRM PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_gAMA_SUPPORTED
-PNG_EXTERN void png_handle_gAMA PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_hIST_SUPPORTED
-PNG_EXTERN void png_handle_hIST PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_iCCP_SUPPORTED
-PNG_EXTERN void png_handle_iCCP PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif /* PNG_READ_iCCP_SUPPORTED */
-
-#ifdef PNG_READ_iTXt_SUPPORTED
-PNG_EXTERN void png_handle_iTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_oFFs_SUPPORTED
-PNG_EXTERN void png_handle_oFFs PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-PNG_EXTERN void png_handle_pCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_pHYs_SUPPORTED
-PNG_EXTERN void png_handle_pHYs PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_sBIT_SUPPORTED
-PNG_EXTERN void png_handle_sBIT PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_sCAL_SUPPORTED
-PNG_EXTERN void png_handle_sCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_sPLT_SUPPORTED
-PNG_EXTERN void png_handle_sPLT PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif /* PNG_READ_sPLT_SUPPORTED */
-
-#ifdef PNG_READ_sRGB_SUPPORTED
-PNG_EXTERN void png_handle_sRGB PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_tEXt_SUPPORTED
-PNG_EXTERN void png_handle_tEXt PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_tIME_SUPPORTED
-PNG_EXTERN void png_handle_tIME PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_tRNS_SUPPORTED
-PNG_EXTERN void png_handle_tRNS PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_READ_zTXt_SUPPORTED
-PNG_EXTERN void png_handle_zTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 length));
-#endif
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-PNG_EXTERN void png_handle_unknown PNGARG((png_structp png_ptr,
-    png_infop info_ptr, png_uint_32 length));
-#endif
-
-PNG_EXTERN void png_check_chunk_name PNGARG((png_structp png_ptr,
-    png_uint_32 chunk_name));
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-/* Exactly as png_handle_as_unknown() except that the argument is a 32-bit chunk
- * name, not a string.
- */
-PNG_EXTERN int png_chunk_unknown_handling PNGARG((png_structp png_ptr,
-    png_uint_32 chunk_name));
-#endif
-
-/* Handle the transformations for reading and writing */
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-PNG_EXTERN void png_do_read_transformations PNGARG((png_structp png_ptr,
-   png_row_infop row_info));
-#endif
-#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
-PNG_EXTERN void png_do_write_transformations PNGARG((png_structp png_ptr,
-   png_row_infop row_info));
-#endif
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-PNG_EXTERN void png_init_read_transformations PNGARG((png_structp png_ptr));
-#endif
-
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-PNG_EXTERN void png_push_read_chunk PNGARG((png_structp png_ptr,
-    png_infop info_ptr));
-PNG_EXTERN void png_push_read_sig PNGARG((png_structp png_ptr,
-    png_infop info_ptr));
-PNG_EXTERN void png_push_check_crc PNGARG((png_structp png_ptr));
-PNG_EXTERN void png_push_crc_skip PNGARG((png_structp png_ptr,
-    png_uint_32 length));
-PNG_EXTERN void png_push_crc_finish PNGARG((png_structp png_ptr));
-PNG_EXTERN void png_push_save_buffer PNGARG((png_structp png_ptr));
-PNG_EXTERN void png_push_restore_buffer PNGARG((png_structp png_ptr,
-    png_bytep buffer, png_size_t buffer_length));
-PNG_EXTERN void png_push_read_IDAT PNGARG((png_structp png_ptr));
-PNG_EXTERN void png_process_IDAT_data PNGARG((png_structp png_ptr,
-    png_bytep buffer, png_size_t buffer_length));
-PNG_EXTERN void png_push_process_row PNGARG((png_structp png_ptr));
-PNG_EXTERN void png_push_handle_unknown PNGARG((png_structp png_ptr,
-   png_infop info_ptr, png_uint_32 length));
-PNG_EXTERN void png_push_have_info PNGARG((png_structp png_ptr,
-   png_infop info_ptr));
-PNG_EXTERN void png_push_have_end PNGARG((png_structp png_ptr,
-   png_infop info_ptr));
-PNG_EXTERN void png_push_have_row PNGARG((png_structp png_ptr, png_bytep row));
-PNG_EXTERN void png_push_read_end PNGARG((png_structp png_ptr,
-    png_infop info_ptr));
-PNG_EXTERN void png_process_some_data PNGARG((png_structp png_ptr,
-    png_infop info_ptr));
-PNG_EXTERN void png_read_push_finish_row PNGARG((png_structp png_ptr));
-#  ifdef PNG_READ_tEXt_SUPPORTED
-PNG_EXTERN void png_push_handle_tEXt PNGARG((png_structp png_ptr,
-    png_infop info_ptr, png_uint_32 length));
-PNG_EXTERN void png_push_read_tEXt PNGARG((png_structp png_ptr,
-    png_infop info_ptr));
-#  endif
-#  ifdef PNG_READ_zTXt_SUPPORTED
-PNG_EXTERN void png_push_handle_zTXt PNGARG((png_structp png_ptr,
-    png_infop info_ptr, png_uint_32 length));
-PNG_EXTERN void png_push_read_zTXt PNGARG((png_structp png_ptr,
-    png_infop info_ptr));
-#  endif
-#  ifdef PNG_READ_iTXt_SUPPORTED
-PNG_EXTERN void png_push_handle_iTXt PNGARG((png_structp png_ptr,
-    png_infop info_ptr, png_uint_32 length));
-PNG_EXTERN void png_push_read_iTXt PNGARG((png_structp png_ptr,
-    png_infop info_ptr));
-#  endif
-
-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-PNG_EXTERN void png_do_read_intrapixel PNGARG((png_row_infop row_info,
-    png_bytep row));
-PNG_EXTERN void png_do_write_intrapixel PNGARG((png_row_infop row_info,
-    png_bytep row));
-#endif
-
-/* Added at libpng version 1.4.0 */
-#ifdef PNG_CHECK_cHRM_SUPPORTED
-PNG_EXTERN int png_check_cHRM_fixed PNGARG((png_structp png_ptr,
-    png_fixed_point int_white_x, png_fixed_point int_white_y,
-    png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
-    int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
-    png_fixed_point int_blue_y));
-#endif
-
-#ifdef PNG_CHECK_cHRM_SUPPORTED
-/* Added at libpng version 1.2.34 and 1.4.0 */
-/* Currently only used by png_check_cHRM_fixed */
-PNG_EXTERN void png_64bit_product PNGARG((long v1, long v2,
-    unsigned long *hi_product, unsigned long *lo_product));
-#endif
-
-#ifdef PNG_cHRM_SUPPORTED
-/* Added at libpng version 1.5.5 */
-typedef struct png_xy
-{
-   png_fixed_point redx, redy;
-   png_fixed_point greenx, greeny;
-   png_fixed_point bluex, bluey;
-   png_fixed_point whitex, whitey;
-} png_xy;
-
-typedef struct png_XYZ
-{
-   png_fixed_point redX, redY, redZ;
-   png_fixed_point greenX, greenY, greenZ;
-   png_fixed_point blueX, blueY, blueZ;
-} png_XYZ;
-
-/* The conversion APIs return 0 on success, non-zero on a parameter error. They
- * allow conversion between the above representations of a color encoding.  When
- * converting from XYZ end points to chromaticities the absolute magnitude of
- * the end points is lost, when converting back the sum of the Y values of the
- * three end points will be 1.0
- */
-PNG_EXTERN int png_xy_from_XYZ PNGARG((png_xy *xy, png_XYZ XYZ));
-PNG_EXTERN int png_XYZ_from_xy PNGARG((png_XYZ *XYZ, png_xy xy));
-PNG_EXTERN int png_XYZ_from_xy_checked PNGARG((png_structp png_ptr,
-   png_XYZ *XYZ, png_xy xy));
-#endif
-
-/* Added at libpng version 1.4.0 */
-PNG_EXTERN void png_check_IHDR PNGARG((png_structp png_ptr,
-    png_uint_32 width, png_uint_32 height, int bit_depth,
-    int color_type, int interlace_type, int compression_type,
-    int filter_type));
-
-/* Added at libpng version 1.5.10 */
-#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
-    defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
-PNG_EXTERN void png_do_check_palette_indexes PNGARG((png_structp png_ptr,
-    png_row_infop row_info));
-#endif
-
-/* Free all memory used by the read (old method - NOT DLL EXPORTED) */
-PNG_EXTERN void png_read_destroy PNGARG((png_structp png_ptr,
-    png_infop info_ptr, png_infop end_info_ptr));
-
-/* Free any memory used in png_ptr struct (old method - NOT DLL EXPORTED) */
-PNG_EXTERN void png_write_destroy PNGARG((png_structp png_ptr));
-
-#ifdef USE_FAR_KEYWORD  /* memory model conversion function */
-PNG_EXTERN void *png_far_to_near PNGARG((png_structp png_ptr, png_voidp ptr,
-    int check));
-#endif /* USE_FAR_KEYWORD */
-
-#if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
-PNG_EXTERN PNG_FUNCTION(void, png_fixed_error, (png_structp png_ptr,
-   png_const_charp name),PNG_NORETURN);
-#endif
-
-/* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
- * the end.  Always leaves the buffer nul terminated.  Never errors out (and
- * there is no error code.)
- */
-PNG_EXTERN size_t png_safecat(png_charp buffer, size_t bufsize, size_t pos,
-    png_const_charp string);
-
-/* Various internal functions to handle formatted warning messages, currently
- * only implemented for warnings.
- */
-#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
-/* Utility to dump an unsigned value into a buffer, given a start pointer and
- * and end pointer (which should point just *beyond* the end of the buffer!)
- * Returns the pointer to the start of the formatted string.  This utility only
- * does unsigned values.
- */
-PNG_EXTERN png_charp png_format_number(png_const_charp start, png_charp end,
-   int format, png_alloc_size_t number);
-
-/* Convenience macro that takes an array: */
-#define PNG_FORMAT_NUMBER(buffer,format,number) \
-   png_format_number(buffer, buffer + (sizeof buffer), format, number)
-
-/* Suggested size for a number buffer (enough for 64 bits and a sign!) */
-#define PNG_NUMBER_BUFFER_SIZE 24
-
-/* These are the integer formats currently supported, the name is formed from
- * the standard printf(3) format string.
- */
-#define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
-#define PNG_NUMBER_FORMAT_02u   2
-#define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
-#define PNG_NUMBER_FORMAT_02d   2
-#define PNG_NUMBER_FORMAT_x     3
-#define PNG_NUMBER_FORMAT_02x   4
-#define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
-#endif
-
-#ifdef PNG_WARNINGS_SUPPORTED
-/* New defines and members adding in libpng-1.5.4 */
-#  define PNG_WARNING_PARAMETER_SIZE 32
-#  define PNG_WARNING_PARAMETER_COUNT 8
-
-/* An l-value of this type has to be passed to the APIs below to cache the
- * values of the parameters to a formatted warning message.
- */
-typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
-   PNG_WARNING_PARAMETER_SIZE];
-
-PNG_EXTERN void png_warning_parameter(png_warning_parameters p, int number,
-    png_const_charp string);
-    /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
-     * including the trailing '\0'.
-     */
-PNG_EXTERN void png_warning_parameter_unsigned(png_warning_parameters p,
-    int number, int format, png_alloc_size_t value);
-    /* Use png_alloc_size_t because it is an unsigned type as big as any we
-     * need to output.  Use the following for a signed value.
-     */
-PNG_EXTERN void png_warning_parameter_signed(png_warning_parameters p,
-    int number, int format, png_int_32 value);
-
-PNG_EXTERN void png_formatted_warning(png_structp png_ptr,
-    png_warning_parameters p, png_const_charp message);
-    /* 'message' follows the X/Open approach of using @1, @2 to insert
-     * parameters previously supplied using the above functions.  Errors in
-     * specifying the paramters will simple result in garbage substitutions.
-     */
-#endif
-
-/* ASCII to FP interfaces, currently only implemented if sCAL
- * support is required.
- */
-#if defined(PNG_READ_sCAL_SUPPORTED)
-/* MAX_DIGITS is actually the maximum number of characters in an sCAL
- * width or height, derived from the precision (number of significant
- * digits - a build time settable option) and assumpitions about the
- * maximum ridiculous exponent.
- */
-#define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
-
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-PNG_EXTERN void png_ascii_from_fp PNGARG((png_structp png_ptr, png_charp ascii,
-    png_size_t size, double fp, unsigned int precision));
-#endif /* FLOATING_POINT */
-
-#ifdef PNG_FIXED_POINT_SUPPORTED
-PNG_EXTERN void png_ascii_from_fixed PNGARG((png_structp png_ptr,
-    png_charp ascii, png_size_t size, png_fixed_point fp));
-#endif /* FIXED_POINT */
-#endif /* READ_sCAL */
-
-#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
-/* An internal API to validate the format of a floating point number.
- * The result is the index of the next character.  If the number is
- * not valid it will be the index of a character in the supposed number.
- *
- * The format of a number is defined in the PNG extensions specification
- * and this API is strictly conformant to that spec, not anyone elses!
- *
- * The format as a regular expression is:
- *
- * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
- *
- * or:
- *
- * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
- *
- * The complexity is that either integer or fraction must be present and the
- * fraction is permitted to have no digits only if the integer is present.
- *
- * NOTE: The dangling E problem.
- *   There is a PNG valid floating point number in the following:
- *
- *       PNG floating point numb1.ers are not greedy.
- *
- *   Working this out requires *TWO* character lookahead (because of the
- *   sign), the parser does not do this - it will fail at the 'r' - this
- *   doesn't matter for PNG sCAL chunk values, but it requires more care
- *   if the value were ever to be embedded in something more complex.  Use
- *   ANSI-C strtod if you need the lookahead.
- */
-/* State table for the parser. */
-#define PNG_FP_INTEGER    0  /* before or in integer */
-#define PNG_FP_FRACTION   1  /* before or in fraction */
-#define PNG_FP_EXPONENT   2  /* before or in exponent */
-#define PNG_FP_STATE      3  /* mask for the above */
-#define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
-#define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
-#define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
-#define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
-#define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
-
-/* These three values don't affect the parser.  They are set but not used.
- */
-#define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
-#define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
-#define PNG_FP_NONZERO  256  /* A non-zero value */
-#define PNG_FP_STICKY   448  /* The above three flags */
-
-/* This is available for the caller to store in 'state' if required.  Do not
- * call the parser after setting it (the parser sometimes clears it.)
- */
-#define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
-
-/* Result codes for the parser (boolean - true meants ok, false means
- * not ok yet.)
- */
-#define PNG_FP_MAYBE      0  /* The number may be valid in the future */
-#define PNG_FP_OK         1  /* The number is valid */
-
-/* Tests on the sticky non-zero and negative flags.  To pass these checks
- * the state must also indicate that the whole number is valid - this is
- * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
- * is equivalent to PNG_FP_OK above.)
- */
-#define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
-   /* NZ_MASK: the string is valid and a non-zero negative value */
-#define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
-   /* Z MASK: the string is valid and a non-zero value. */
-   /* PNG_FP_SAW_DIGIT: the string is valid. */
-#define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
-#define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
-#define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
- 
-/* The actual parser.  This can be called repeatedly, it updates
- * the index into the string and the state variable (which must
- * be initialzed to 0).  It returns a result code, as above.  There
- * is no point calling the parser any more if it fails to advance to
- * the end of the string - it is stuck on an invalid character (or
- * terminated by '\0').
- *
- * Note that the pointer will consume an E or even an E+ then leave
- * a 'maybe' state even though a preceding integer.fraction is valid.
- * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
- * a valid number.  It's possible to recover from this by calling
- * the parser again (from the start, with state 0) but with a string
- * that omits the last character (i.e. set the size to the index of
- * the problem character.)  This has not been tested within libpng.
- */
-PNG_EXTERN int png_check_fp_number PNGARG((png_const_charp string,
-    png_size_t size, int *statep, png_size_tp whereami));
-
-/* This is the same but it checks a complete string and returns true
- * only if it just contains a floating point number.  As of 1.5.4 this
- * function also returns the state at the end of parsing the number if
- * it was valid (otherwise it returns 0.)  This can be used for testing
- * for negative or zero values using the sticky flag.
- */
-PNG_EXTERN int png_check_fp_string PNGARG((png_const_charp string,
-    png_size_t size));
-#endif /* pCAL || sCAL */
-
-#if defined(PNG_READ_GAMMA_SUPPORTED) ||\
-    defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
-/* Added at libpng version 1.5.0 */
-/* This is a utility to provide a*times/div (rounded) and indicate
- * if there is an overflow.  The result is a boolean - false (0)
- * for overflow, true (1) if no overflow, in which case *res
- * holds the result.
- */
-PNG_EXTERN int png_muldiv PNGARG((png_fixed_point_p res, png_fixed_point a,
-    png_int_32 multiplied_by, png_int_32 divided_by));
-#endif
-
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
-/* Same deal, but issue a warning on overflow and return 0. */
-PNG_EXTERN png_fixed_point png_muldiv_warn PNGARG((png_structp png_ptr,
-    png_fixed_point a, png_int_32 multiplied_by, png_int_32 divided_by));
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-/* Calculate a reciprocal - used for gamma values.  This returns
- * 0 if the argument is 0 in order to maintain an undefined value,
- * there are no warnings.
- */
-PNG_EXTERN png_fixed_point png_reciprocal PNGARG((png_fixed_point a));
-
-/* The same but gives a reciprocal of the product of two fixed point
- * values.  Accuracy is suitable for gamma calculations but this is
- * not exact - use png_muldiv for that.
- */
-PNG_EXTERN png_fixed_point png_reciprocal2 PNGARG((png_fixed_point a,
-    png_fixed_point b));
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-/* Internal fixed point gamma correction.  These APIs are called as
- * required to convert single values - they don't need to be fast,
- * they are not used when processing image pixel values.
- *
- * While the input is an 'unsigned' value it must actually be the
- * correct bit value - 0..255 or 0..65535 as required.
- */
-PNG_EXTERN png_uint_16 png_gamma_correct PNGARG((png_structp png_ptr,
-    unsigned int value, png_fixed_point gamma_value));
-PNG_EXTERN int png_gamma_significant PNGARG((png_fixed_point gamma_value));
-PNG_EXTERN png_uint_16 png_gamma_16bit_correct PNGARG((unsigned int value,
-    png_fixed_point gamma_value));
-PNG_EXTERN png_byte png_gamma_8bit_correct PNGARG((unsigned int value,
-    png_fixed_point gamma_value));
-PNG_EXTERN void png_destroy_gamma_table(png_structp png_ptr);
-PNG_EXTERN void png_build_gamma_table PNGARG((png_structp png_ptr,
-    int bit_depth));
-#endif
-
-/* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
-
-#include "pngdebug.h"
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* PNGPRIV_H */
diff --git a/extern/libpng/include/pngread.c b/extern/libpng/include/pngread.c
deleted file mode 100644
index 1d8c6b3346..0000000000
--- a/extern/libpng/include/pngread.c
+++ /dev/null
@@ -1,1305 +0,0 @@
-
-/* pngread.c - read a PNG file
- *
- * Last changed in libpng 1.5.10 [March 8, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * This file contains routines that an application calls directly to
- * read a PNG file or stream.
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_READ_SUPPORTED
-
-/* Create a PNG structure for reading, and allocate any memory needed. */
-PNG_FUNCTION(png_structp,PNGAPI
-png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
-    png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
-{
-
-#ifdef PNG_USER_MEM_SUPPORTED
-   return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
-       warn_fn, NULL, NULL, NULL));
-}
-
-/* Alternate create PNG structure for reading, and allocate any memory
- * needed.
- */
-PNG_FUNCTION(png_structp,PNGAPI
-png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
-    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
-    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
-{
-#endif /* PNG_USER_MEM_SUPPORTED */
-
-#ifdef PNG_SETJMP_SUPPORTED
-   volatile
-#endif
-   png_structp png_ptr;
-   volatile int png_cleanup_needed = 0;
-
-#ifdef PNG_SETJMP_SUPPORTED
-#ifdef USE_FAR_KEYWORD
-   jmp_buf tmp_jmpbuf;
-#endif
-#endif
-
-   png_debug(1, "in png_create_read_struct");
-
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
-       malloc_fn, mem_ptr);
-#else
-   png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
-#endif
-   if (png_ptr == NULL)
-      return (NULL);
-
-   /* Added at libpng-1.2.6 */
-#ifdef PNG_USER_LIMITS_SUPPORTED
-   png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
-   png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
-
-   /* Added at libpng-1.2.43 and 1.4.0 */
-   png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
-
-   /* Added at libpng-1.2.43 and 1.4.1 */
-   png_ptr->user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
-#endif
-
-#ifdef PNG_SETJMP_SUPPORTED
-/* Applications that neglect to set up their own setjmp() and then
- * encounter a png_error() will longjmp here.  Since the jmpbuf is
- * then meaningless we abort instead of returning.
- */
-#ifdef USE_FAR_KEYWORD
-   if (setjmp(tmp_jmpbuf))
-#else
-   if (setjmp(png_jmpbuf(png_ptr))) /* Sets longjmp to match setjmp */
-#endif
-      PNG_ABORT();
-#ifdef USE_FAR_KEYWORD
-   png_memcpy(png_jmpbuf(png_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
-#endif
-#endif /* PNG_SETJMP_SUPPORTED */
-
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
-#endif
-
-   png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
-
-   /* Call the general version checker (shared with read and write code): */
-   if (!png_user_version_check(png_ptr, user_png_ver))
-      png_cleanup_needed = 1;
-
-   if (!png_cleanup_needed)
-   {
-   /* Initialize zbuf - compression buffer */
-   png_ptr->zbuf_size = PNG_ZBUF_SIZE;
-   png_ptr->zbuf = (png_bytep)png_malloc_warn(png_ptr, png_ptr->zbuf_size);
-
-   if (png_ptr->zbuf == NULL)
-      png_cleanup_needed = 1;
-   }
-
-   png_ptr->zstream.zalloc = png_zalloc;
-   png_ptr->zstream.zfree = png_zfree;
-   png_ptr->zstream.opaque = (voidpf)png_ptr;
-
-   if (!png_cleanup_needed)
-   {
-      switch (inflateInit(&png_ptr->zstream))
-      {
-         case Z_OK:
-            break; /* Do nothing */
-
-         case Z_MEM_ERROR:
-            png_warning(png_ptr, "zlib memory error");
-            png_cleanup_needed = 1;
-            break;
-
-         case Z_STREAM_ERROR:
-            png_warning(png_ptr, "zlib stream error");
-            png_cleanup_needed = 1;
-            break;
-
-         case Z_VERSION_ERROR:
-            png_warning(png_ptr, "zlib version error");
-            png_cleanup_needed = 1;
-            break;
-
-         default: png_warning(png_ptr, "Unknown zlib error");
-            png_cleanup_needed = 1;
-      }
-   }
-
-   if (png_cleanup_needed)
-   {
-      /* Clean up PNG structure and deallocate any memory. */
-      png_free(png_ptr, png_ptr->zbuf);
-      png_ptr->zbuf = NULL;
-#ifdef PNG_USER_MEM_SUPPORTED
-      png_destroy_struct_2((png_voidp)png_ptr,
-          (png_free_ptr)free_fn, (png_voidp)mem_ptr);
-#else
-      png_destroy_struct((png_voidp)png_ptr);
-#endif
-      return (NULL);
-   }
-
-   png_ptr->zstream.next_out = png_ptr->zbuf;
-   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-
-   png_set_read_fn(png_ptr, NULL, NULL);
-
-
-   return (png_ptr);
-}
-
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Read the information before the actual image data.  This has been
- * changed in v0.90 to allow reading a file that already has the magic
- * bytes read from the stream.  You can tell libpng how many bytes have
- * been read from the beginning of the stream (up to the maximum of 8)
- * via png_set_sig_bytes(), and we will only check the remaining bytes
- * here.  The application can then have access to the signature bytes we
- * read if it is determined that this isn't a valid PNG file.
- */
-void PNGAPI
-png_read_info(png_structp png_ptr, png_infop info_ptr)
-{
-   png_debug(1, "in png_read_info");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   /* Read and check the PNG file signature. */
-   png_read_sig(png_ptr, info_ptr);
-
-   for (;;)
-   {
-      png_uint_32 length = png_read_chunk_header(png_ptr);
-      png_uint_32 chunk_name = png_ptr->chunk_name;
-
-      /* This should be a binary subdivision search or a hash for
-       * matching the chunk name rather than a linear search.
-       */
-      if (chunk_name == png_IDAT)
-         if (png_ptr->mode & PNG_AFTER_IDAT)
-            png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
-
-      if (chunk_name == png_IHDR)
-         png_handle_IHDR(png_ptr, info_ptr, length);
-
-      else if (chunk_name == png_IEND)
-         png_handle_IEND(png_ptr, info_ptr, length);
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-      else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
-         PNG_HANDLE_CHUNK_AS_DEFAULT)
-      {
-         if (chunk_name == png_IDAT)
-            png_ptr->mode |= PNG_HAVE_IDAT;
-
-         png_handle_unknown(png_ptr, info_ptr, length);
-
-         if (chunk_name == png_PLTE)
-            png_ptr->mode |= PNG_HAVE_PLTE;
-
-         else if (chunk_name == png_IDAT)
-         {
-            if (!(png_ptr->mode & PNG_HAVE_IHDR))
-               png_error(png_ptr, "Missing IHDR before IDAT");
-
-            else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-                !(png_ptr->mode & PNG_HAVE_PLTE))
-               png_error(png_ptr, "Missing PLTE before IDAT");
-
-            break;
-         }
-      }
-#endif
-      else if (chunk_name == png_PLTE)
-         png_handle_PLTE(png_ptr, info_ptr, length);
-
-      else if (chunk_name == png_IDAT)
-      {
-         if (!(png_ptr->mode & PNG_HAVE_IHDR))
-            png_error(png_ptr, "Missing IHDR before IDAT");
-
-         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-             !(png_ptr->mode & PNG_HAVE_PLTE))
-            png_error(png_ptr, "Missing PLTE before IDAT");
-
-         png_ptr->idat_size = length;
-         png_ptr->mode |= PNG_HAVE_IDAT;
-         break;
-      }
-
-#ifdef PNG_READ_bKGD_SUPPORTED
-      else if (chunk_name == png_bKGD)
-         png_handle_bKGD(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_cHRM_SUPPORTED
-      else if (chunk_name == png_cHRM)
-         png_handle_cHRM(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_gAMA_SUPPORTED
-      else if (chunk_name == png_gAMA)
-         png_handle_gAMA(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_hIST_SUPPORTED
-      else if (chunk_name == png_hIST)
-         png_handle_hIST(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_oFFs_SUPPORTED
-      else if (chunk_name == png_oFFs)
-         png_handle_oFFs(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-      else if (chunk_name == png_pCAL)
-         png_handle_pCAL(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sCAL_SUPPORTED
-      else if (chunk_name == png_sCAL)
-         png_handle_sCAL(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_pHYs_SUPPORTED
-      else if (chunk_name == png_pHYs)
-         png_handle_pHYs(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sBIT_SUPPORTED
-      else if (chunk_name == png_sBIT)
-         png_handle_sBIT(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sRGB_SUPPORTED
-      else if (chunk_name == png_sRGB)
-         png_handle_sRGB(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_iCCP_SUPPORTED
-      else if (chunk_name == png_iCCP)
-         png_handle_iCCP(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sPLT_SUPPORTED
-      else if (chunk_name == png_sPLT)
-         png_handle_sPLT(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tEXt_SUPPORTED
-      else if (chunk_name == png_tEXt)
-         png_handle_tEXt(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tIME_SUPPORTED
-      else if (chunk_name == png_tIME)
-         png_handle_tIME(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tRNS_SUPPORTED
-      else if (chunk_name == png_tRNS)
-         png_handle_tRNS(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_zTXt_SUPPORTED
-      else if (chunk_name == png_zTXt)
-         png_handle_zTXt(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_iTXt_SUPPORTED
-      else if (chunk_name == png_iTXt)
-         png_handle_iTXt(png_ptr, info_ptr, length);
-#endif
-
-      else
-         png_handle_unknown(png_ptr, info_ptr, length);
-   }
-}
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
-
-/* Optional call to update the users info_ptr structure */
-void PNGAPI
-png_read_update_info(png_structp png_ptr, png_infop info_ptr)
-{
-   png_debug(1, "in png_read_update_info");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_read_start_row(png_ptr);
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-   png_read_transform_info(png_ptr, info_ptr);
-#else
-   PNG_UNUSED(info_ptr)
-#endif
-}
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Initialize palette, background, etc, after transformations
- * are set, but before any reading takes place.  This allows
- * the user to obtain a gamma-corrected palette, for example.
- * If the user doesn't call this, we will do it ourselves.
- */
-void PNGAPI
-png_start_read_image(png_structp png_ptr)
-{
-   png_debug(1, "in png_start_read_image");
-
-   if (png_ptr != NULL)
-     png_read_start_row(png_ptr);
-}
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-void PNGAPI
-png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
-{
-   int ret;
-
-   png_row_info row_info;
-
-   if (png_ptr == NULL)
-      return;
-
-   png_debug2(1, "in png_read_row (row %lu, pass %d)",
-       (unsigned long)png_ptr->row_number, png_ptr->pass);
-
-   /* png_read_start_row sets the information (in particular iwidth) for this
-    * interlace pass.
-    */
-   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
-      png_read_start_row(png_ptr);
-
-   /* 1.5.6: row_info moved out of png_struct to a local here. */
-   row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
-   row_info.color_type = png_ptr->color_type;
-   row_info.bit_depth = png_ptr->bit_depth;
-   row_info.channels = png_ptr->channels;
-   row_info.pixel_depth = png_ptr->pixel_depth;
-   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
-
-   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
-   {
-   /* Check for transforms that have been set but were defined out */
-#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
-   if (png_ptr->transformations & PNG_INVERT_MONO)
-      png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
-#endif
-
-#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
-   if (png_ptr->transformations & PNG_FILLER)
-      png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
-#endif
-
-#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
-    !defined(PNG_READ_PACKSWAP_SUPPORTED)
-   if (png_ptr->transformations & PNG_PACKSWAP)
-      png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
-#endif
-
-#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
-   if (png_ptr->transformations & PNG_PACK)
-      png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
-#endif
-
-#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
-   if (png_ptr->transformations & PNG_SHIFT)
-      png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
-#endif
-
-#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
-   if (png_ptr->transformations & PNG_BGR)
-      png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
-#endif
-
-#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
-      png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
-#endif
-   }
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* If interlaced and we do not need a new row, combine row and return.
-    * Notice that the pixels we have from previous rows have been transformed
-    * already; we can only combine like with like (transformed or
-    * untransformed) and, because of the libpng API for interlaced images, this
-    * means we must transform before de-interlacing.
-    */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
-   {
-      switch (png_ptr->pass)
-      {
-         case 0:
-            if (png_ptr->row_number & 0x07)
-            {
-               if (dsp_row != NULL)
-                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
-               png_read_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 1:
-            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
-            {
-               if (dsp_row != NULL)
-                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
-
-               png_read_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 2:
-            if ((png_ptr->row_number & 0x07) != 4)
-            {
-               if (dsp_row != NULL && (png_ptr->row_number & 4))
-                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
-
-               png_read_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 3:
-            if ((png_ptr->row_number & 3) || png_ptr->width < 3)
-            {
-               if (dsp_row != NULL)
-                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
-
-               png_read_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 4:
-            if ((png_ptr->row_number & 3) != 2)
-            {
-               if (dsp_row != NULL && (png_ptr->row_number & 2))
-                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
-
-               png_read_finish_row(png_ptr);
-               return;
-            }
-            break;
-         case 5:
-            if ((png_ptr->row_number & 1) || png_ptr->width < 2)
-            {
-               if (dsp_row != NULL)
-                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
-
-               png_read_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         default:
-         case 6:
-            if (!(png_ptr->row_number & 1))
-            {
-               png_read_finish_row(png_ptr);
-               return;
-            }
-            break;
-      }
-   }
-#endif
-
-   if (!(png_ptr->mode & PNG_HAVE_IDAT))
-      png_error(png_ptr, "Invalid attempt to read row data");
-
-   png_ptr->zstream.next_out = png_ptr->row_buf;
-   png_ptr->zstream.avail_out =
-       (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
-       png_ptr->iwidth) + 1);
-
-   do
-   {
-      if (!(png_ptr->zstream.avail_in))
-      {
-         while (!png_ptr->idat_size)
-         {
-            png_crc_finish(png_ptr, 0);
-
-            png_ptr->idat_size = png_read_chunk_header(png_ptr);
-            if (png_ptr->chunk_name != png_IDAT)
-               png_error(png_ptr, "Not enough image data");
-         }
-         png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
-         png_ptr->zstream.next_in = png_ptr->zbuf;
-         if (png_ptr->zbuf_size > png_ptr->idat_size)
-            png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
-         png_crc_read(png_ptr, png_ptr->zbuf,
-             (png_size_t)png_ptr->zstream.avail_in);
-         png_ptr->idat_size -= png_ptr->zstream.avail_in;
-      }
-
-      ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
-
-      if (ret == Z_STREAM_END)
-      {
-         if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
-            png_ptr->idat_size)
-            png_benign_error(png_ptr, "Extra compressed data");
-         png_ptr->mode |= PNG_AFTER_IDAT;
-         png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
-         break;
-      }
-
-      if (ret != Z_OK)
-         png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
-             "Decompression error");
-
-   } while (png_ptr->zstream.avail_out);
-
-   if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
-   {
-      if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
-         png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
-            png_ptr->prev_row + 1, png_ptr->row_buf[0]);
-      else
-         png_error(png_ptr, "bad adaptive filter value");
-   }
-
-   /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
-    * 1.5.6, while the buffer really is this big in current versions of libpng
-    * it may not be in the future, so this was changed just to copy the
-    * interlaced count:
-    */
-   png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
-       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
-   {
-      /* Intrapixel differencing */
-      png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
-   }
-#endif
-
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-   if (png_ptr->transformations)
-      png_do_read_transformations(png_ptr, &row_info);
-#endif
-
-   /* The transformed pixel depth should match the depth now in row_info. */
-   if (png_ptr->transformed_pixel_depth == 0)
-   {
-      png_ptr->transformed_pixel_depth = row_info.pixel_depth;
-      if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
-         png_error(png_ptr, "sequential row overflow");
-   }
-
-   else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
-      png_error(png_ptr, "internal sequential row size calculation error");
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Blow up interlaced rows to full size */
-   if (png_ptr->interlaced &&
-      (png_ptr->transformations & PNG_INTERLACE))
-   {
-      if (png_ptr->pass < 6)
-         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
-            png_ptr->transformations);
-
-      if (dsp_row != NULL)
-         png_combine_row(png_ptr, dsp_row, 1/*display*/);
-
-      if (row != NULL)
-         png_combine_row(png_ptr, row, 0/*row*/);
-   }
-
-   else
-#endif
-   {
-      if (row != NULL)
-         png_combine_row(png_ptr, row, -1/*ignored*/);
-
-      if (dsp_row != NULL)
-         png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
-   }
-   png_read_finish_row(png_ptr);
-
-   if (png_ptr->read_row_fn != NULL)
-      (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
-}
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Read one or more rows of image data.  If the image is interlaced,
- * and png_set_interlace_handling() has been called, the rows need to
- * contain the contents of the rows from the previous pass.  If the
- * image has alpha or transparency, and png_handle_alpha()[*] has been
- * called, the rows contents must be initialized to the contents of the
- * screen.
- *
- * "row" holds the actual image, and pixels are placed in it
- * as they arrive.  If the image is displayed after each pass, it will
- * appear to "sparkle" in.  "display_row" can be used to display a
- * "chunky" progressive image, with finer detail added as it becomes
- * available.  If you do not want this "chunky" display, you may pass
- * NULL for display_row.  If you do not want the sparkle display, and
- * you have not called png_handle_alpha(), you may pass NULL for rows.
- * If you have called png_handle_alpha(), and the image has either an
- * alpha channel or a transparency chunk, you must provide a buffer for
- * rows.  In this case, you do not have to provide a display_row buffer
- * also, but you may.  If the image is not interlaced, or if you have
- * not called png_set_interlace_handling(), the display_row buffer will
- * be ignored, so pass NULL to it.
- *
- * [*] png_handle_alpha() does not exist yet, as of this version of libpng
- */
-
-void PNGAPI
-png_read_rows(png_structp png_ptr, png_bytepp row,
-    png_bytepp display_row, png_uint_32 num_rows)
-{
-   png_uint_32 i;
-   png_bytepp rp;
-   png_bytepp dp;
-
-   png_debug(1, "in png_read_rows");
-
-   if (png_ptr == NULL)
-      return;
-
-   rp = row;
-   dp = display_row;
-   if (rp != NULL && dp != NULL)
-      for (i = 0; i < num_rows; i++)
-      {
-         png_bytep rptr = *rp++;
-         png_bytep dptr = *dp++;
-
-         png_read_row(png_ptr, rptr, dptr);
-      }
-
-   else if (rp != NULL)
-      for (i = 0; i < num_rows; i++)
-      {
-         png_bytep rptr = *rp;
-         png_read_row(png_ptr, rptr, NULL);
-         rp++;
-      }
-
-   else if (dp != NULL)
-      for (i = 0; i < num_rows; i++)
-      {
-         png_bytep dptr = *dp;
-         png_read_row(png_ptr, NULL, dptr);
-         dp++;
-      }
-}
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Read the entire image.  If the image has an alpha channel or a tRNS
- * chunk, and you have called png_handle_alpha()[*], you will need to
- * initialize the image to the current image that PNG will be overlaying.
- * We set the num_rows again here, in case it was incorrectly set in
- * png_read_start_row() by a call to png_read_update_info() or
- * png_start_read_image() if png_set_interlace_handling() wasn't called
- * prior to either of these functions like it should have been.  You can
- * only call this function once.  If you desire to have an image for
- * each pass of a interlaced image, use png_read_rows() instead.
- *
- * [*] png_handle_alpha() does not exist yet, as of this version of libpng
- */
-void PNGAPI
-png_read_image(png_structp png_ptr, png_bytepp image)
-{
-   png_uint_32 i, image_height;
-   int pass, j;
-   png_bytepp rp;
-
-   png_debug(1, "in png_read_image");
-
-   if (png_ptr == NULL)
-      return;
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
-   {
-      pass = png_set_interlace_handling(png_ptr);
-      /* And make sure transforms are initialized. */
-      png_start_read_image(png_ptr);
-   }
-   else
-   {
-      if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
-      {
-         /* Caller called png_start_read_image or png_read_update_info without
-          * first turning on the PNG_INTERLACE transform.  We can fix this here,
-          * but the caller should do it!
-          */
-         png_warning(png_ptr, "Interlace handling should be turned on when "
-            "using png_read_image");
-         /* Make sure this is set correctly */
-         png_ptr->num_rows = png_ptr->height;
-      }
-
-      /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
-       * the above error case.
-       */
-      pass = png_set_interlace_handling(png_ptr);
-   }
-#else
-   if (png_ptr->interlaced)
-      png_error(png_ptr,
-          "Cannot read interlaced image -- interlace handler disabled");
-
-   pass = 1;
-#endif
-
-   image_height=png_ptr->height;
-
-   for (j = 0; j < pass; j++)
-   {
-      rp = image;
-      for (i = 0; i < image_height; i++)
-      {
-         png_read_row(png_ptr, *rp, NULL);
-         rp++;
-      }
-   }
-}
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-/* Read the end of the PNG file.  Will not read past the end of the
- * file, will verify the end is accurate, and will read any comments
- * or time information at the end of the file, if info is not NULL.
- */
-void PNGAPI
-png_read_end(png_structp png_ptr, png_infop info_ptr)
-{
-   png_debug(1, "in png_read_end");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
-
-#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
-   /* Report invalid palette index; added at libng-1.5.10 */
-   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-      png_ptr->num_palette_max > png_ptr->num_palette)
-     png_benign_error(png_ptr, "Read palette index exceeding num_palette");
-#endif
-
-   do
-   {
-      png_uint_32 length = png_read_chunk_header(png_ptr);
-      png_uint_32 chunk_name = png_ptr->chunk_name;
-
-      if (chunk_name == png_IHDR)
-         png_handle_IHDR(png_ptr, info_ptr, length);
-
-      else if (chunk_name == png_IEND)
-         png_handle_IEND(png_ptr, info_ptr, length);
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-      else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
-         PNG_HANDLE_CHUNK_AS_DEFAULT)
-      {
-         if (chunk_name == png_IDAT)
-         {
-            if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
-               png_benign_error(png_ptr, "Too many IDATs found");
-         }
-         png_handle_unknown(png_ptr, info_ptr, length);
-         if (chunk_name == png_PLTE)
-            png_ptr->mode |= PNG_HAVE_PLTE;
-      }
-#endif
-
-      else if (chunk_name == png_IDAT)
-      {
-         /* Zero length IDATs are legal after the last IDAT has been
-          * read, but not after other chunks have been read.
-          */
-         if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
-            png_benign_error(png_ptr, "Too many IDATs found");
-
-         png_crc_finish(png_ptr, length);
-      }
-      else if (chunk_name == png_PLTE)
-         png_handle_PLTE(png_ptr, info_ptr, length);
-
-#ifdef PNG_READ_bKGD_SUPPORTED
-      else if (chunk_name == png_bKGD)
-         png_handle_bKGD(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_cHRM_SUPPORTED
-      else if (chunk_name == png_cHRM)
-         png_handle_cHRM(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_gAMA_SUPPORTED
-      else if (chunk_name == png_gAMA)
-         png_handle_gAMA(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_hIST_SUPPORTED
-      else if (chunk_name == png_hIST)
-         png_handle_hIST(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_oFFs_SUPPORTED
-      else if (chunk_name == png_oFFs)
-         png_handle_oFFs(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-      else if (chunk_name == png_pCAL)
-         png_handle_pCAL(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sCAL_SUPPORTED
-      else if (chunk_name == png_sCAL)
-         png_handle_sCAL(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_pHYs_SUPPORTED
-      else if (chunk_name == png_pHYs)
-         png_handle_pHYs(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sBIT_SUPPORTED
-      else if (chunk_name == png_sBIT)
-         png_handle_sBIT(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sRGB_SUPPORTED
-      else if (chunk_name == png_sRGB)
-         png_handle_sRGB(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_iCCP_SUPPORTED
-      else if (chunk_name == png_iCCP)
-         png_handle_iCCP(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sPLT_SUPPORTED
-      else if (chunk_name == png_sPLT)
-         png_handle_sPLT(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tEXt_SUPPORTED
-      else if (chunk_name == png_tEXt)
-         png_handle_tEXt(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tIME_SUPPORTED
-      else if (chunk_name == png_tIME)
-         png_handle_tIME(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tRNS_SUPPORTED
-      else if (chunk_name == png_tRNS)
-         png_handle_tRNS(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_zTXt_SUPPORTED
-      else if (chunk_name == png_zTXt)
-         png_handle_zTXt(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_iTXt_SUPPORTED
-      else if (chunk_name == png_iTXt)
-         png_handle_iTXt(png_ptr, info_ptr, length);
-#endif
-
-      else
-         png_handle_unknown(png_ptr, info_ptr, length);
-   } while (!(png_ptr->mode & PNG_HAVE_IEND));
-}
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
-
-/* Free all memory used by the read */
-void PNGAPI
-png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
-    png_infopp end_info_ptr_ptr)
-{
-   png_structp png_ptr = NULL;
-   png_infop info_ptr = NULL, end_info_ptr = NULL;
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_free_ptr free_fn = NULL;
-   png_voidp mem_ptr = NULL;
-#endif
-
-   png_debug(1, "in png_destroy_read_struct");
-
-   if (png_ptr_ptr != NULL)
-      png_ptr = *png_ptr_ptr;
-   if (png_ptr == NULL)
-      return;
-
-#ifdef PNG_USER_MEM_SUPPORTED
-   free_fn = png_ptr->free_fn;
-   mem_ptr = png_ptr->mem_ptr;
-#endif
-
-   if (info_ptr_ptr != NULL)
-      info_ptr = *info_ptr_ptr;
-
-   if (end_info_ptr_ptr != NULL)
-      end_info_ptr = *end_info_ptr_ptr;
-
-   png_read_destroy(png_ptr, info_ptr, end_info_ptr);
-
-   if (info_ptr != NULL)
-   {
-#ifdef PNG_TEXT_SUPPORTED
-      png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
-#endif
-
-#ifdef PNG_USER_MEM_SUPPORTED
-      png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
-          (png_voidp)mem_ptr);
-#else
-      png_destroy_struct((png_voidp)info_ptr);
-#endif
-      *info_ptr_ptr = NULL;
-   }
-
-   if (end_info_ptr != NULL)
-   {
-#ifdef PNG_READ_TEXT_SUPPORTED
-      png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
-#endif
-#ifdef PNG_USER_MEM_SUPPORTED
-      png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
-          (png_voidp)mem_ptr);
-#else
-      png_destroy_struct((png_voidp)end_info_ptr);
-#endif
-      *end_info_ptr_ptr = NULL;
-   }
-
-   if (png_ptr != NULL)
-   {
-#ifdef PNG_USER_MEM_SUPPORTED
-      png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
-          (png_voidp)mem_ptr);
-#else
-      png_destroy_struct((png_voidp)png_ptr);
-#endif
-      *png_ptr_ptr = NULL;
-   }
-}
-
-/* Free all memory used by the read (old method) */
-void /* PRIVATE */
-png_read_destroy(png_structp png_ptr, png_infop info_ptr,
-    png_infop end_info_ptr)
-{
-#ifdef PNG_SETJMP_SUPPORTED
-   jmp_buf tmp_jmp;
-#endif
-   png_error_ptr error_fn;
-#ifdef PNG_WARNINGS_SUPPORTED
-   png_error_ptr warning_fn;
-#endif
-   png_voidp error_ptr;
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_free_ptr free_fn;
-#endif
-
-   png_debug(1, "in png_read_destroy");
-
-   if (info_ptr != NULL)
-      png_info_destroy(png_ptr, info_ptr);
-
-   if (end_info_ptr != NULL)
-      png_info_destroy(png_ptr, end_info_ptr);
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   png_destroy_gamma_table(png_ptr);
-#endif
-
-   png_free(png_ptr, png_ptr->zbuf);
-   png_free(png_ptr, png_ptr->big_row_buf);
-   png_free(png_ptr, png_ptr->big_prev_row);
-   png_free(png_ptr, png_ptr->chunkdata);
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-   png_free(png_ptr, png_ptr->palette_lookup);
-   png_free(png_ptr, png_ptr->quantize_index);
-#endif
-
-   if (png_ptr->free_me & PNG_FREE_PLTE)
-      png_zfree(png_ptr, png_ptr->palette);
-   png_ptr->free_me &= ~PNG_FREE_PLTE;
-
-#if defined(PNG_tRNS_SUPPORTED) || \
-    defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
-   if (png_ptr->free_me & PNG_FREE_TRNS)
-      png_free(png_ptr, png_ptr->trans_alpha);
-   png_ptr->free_me &= ~PNG_FREE_TRNS;
-#endif
-
-#ifdef PNG_READ_hIST_SUPPORTED
-   if (png_ptr->free_me & PNG_FREE_HIST)
-      png_free(png_ptr, png_ptr->hist);
-   png_ptr->free_me &= ~PNG_FREE_HIST;
-#endif
-
-   inflateEnd(&png_ptr->zstream);
-
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-   png_free(png_ptr, png_ptr->save_buffer);
-#endif
-
-   /* Save the important info out of the png_struct, in case it is
-    * being used again.
-    */
-#ifdef PNG_SETJMP_SUPPORTED
-   png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
-#endif
-
-   error_fn = png_ptr->error_fn;
-#ifdef PNG_WARNINGS_SUPPORTED
-   warning_fn = png_ptr->warning_fn;
-#endif
-   error_ptr = png_ptr->error_ptr;
-#ifdef PNG_USER_MEM_SUPPORTED
-   free_fn = png_ptr->free_fn;
-#endif
-
-   png_memset(png_ptr, 0, png_sizeof(png_struct));
-
-   png_ptr->error_fn = error_fn;
-#ifdef PNG_WARNINGS_SUPPORTED
-   png_ptr->warning_fn = warning_fn;
-#endif
-   png_ptr->error_ptr = error_ptr;
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_ptr->free_fn = free_fn;
-#endif
-
-#ifdef PNG_SETJMP_SUPPORTED
-   png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
-#endif
-
-}
-
-void PNGAPI
-png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
-{
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->read_row_fn = read_row_fn;
-}
-
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-#ifdef PNG_INFO_IMAGE_SUPPORTED
-void PNGAPI
-png_read_png(png_structp png_ptr, png_infop info_ptr,
-                           int transforms,
-                           voidp params)
-{
-   int row;
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   /* png_read_info() gives us all of the information from the
-    * PNG file before the first IDAT (image data chunk).
-    */
-   png_read_info(png_ptr, info_ptr);
-   if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
-      png_error(png_ptr, "Image is too high to process with png_read_png()");
-
-   /* -------------- image transformations start here ------------------- */
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-   /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
-    */
-   if (transforms & PNG_TRANSFORM_SCALE_16)
-   {
-     /* Added at libpng-1.5.4. "strip_16" produces the same result that it
-      * did in earlier versions, while "scale_16" is now more accurate.
-      */
-      png_set_scale_16(png_ptr);
-   }
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-   /* If both SCALE and STRIP are required pngrtran will effectively cancel the
-    * latter by doing SCALE first.  This is ok and allows apps not to check for
-    * which is supported to get the right answer.
-    */
-   if (transforms & PNG_TRANSFORM_STRIP_16)
-      png_set_strip_16(png_ptr);
-#endif
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   /* Strip alpha bytes from the input data without combining with
-    * the background (not recommended).
-    */
-   if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
-      png_set_strip_alpha(png_ptr);
-#endif
-
-#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
-   /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
-    * byte into separate bytes (useful for paletted and grayscale images).
-    */
-   if (transforms & PNG_TRANSFORM_PACKING)
-      png_set_packing(png_ptr);
-#endif
-
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
-   /* Change the order of packed pixels to least significant bit first
-    * (not useful if you are using png_set_packing).
-    */
-   if (transforms & PNG_TRANSFORM_PACKSWAP)
-      png_set_packswap(png_ptr);
-#endif
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-   /* Expand paletted colors into true RGB triplets
-    * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
-    * Expand paletted or RGB images with transparency to full alpha
-    * channels so the data will be available as RGBA quartets.
-    */
-   if (transforms & PNG_TRANSFORM_EXPAND)
-      if ((png_ptr->bit_depth < 8) ||
-          (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
-          (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
-         png_set_expand(png_ptr);
-#endif
-
-   /* We don't handle background color or gamma transformation or quantizing.
-    */
-
-#ifdef PNG_READ_INVERT_SUPPORTED
-   /* Invert monochrome files to have 0 as white and 1 as black
-    */
-   if (transforms & PNG_TRANSFORM_INVERT_MONO)
-      png_set_invert_mono(png_ptr);
-#endif
-
-#ifdef PNG_READ_SHIFT_SUPPORTED
-   /* If you want to shift the pixel values from the range [0,255] or
-    * [0,65535] to the original [0,7] or [0,31], or whatever range the
-    * colors were originally in:
-    */
-   if ((transforms & PNG_TRANSFORM_SHIFT)
-       && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
-   {
-      png_color_8p sig_bit;
-
-      png_get_sBIT(png_ptr, info_ptr, &sig_bit);
-      png_set_shift(png_ptr, sig_bit);
-   }
-#endif
-
-#ifdef PNG_READ_BGR_SUPPORTED
-   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
-   if (transforms & PNG_TRANSFORM_BGR)
-      png_set_bgr(png_ptr);
-#endif
-
-#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
-   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
-   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
-      png_set_swap_alpha(png_ptr);
-#endif
-
-#ifdef PNG_READ_SWAP_SUPPORTED
-   /* Swap bytes of 16-bit files to least significant byte first */
-   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
-      png_set_swap(png_ptr);
-#endif
-
-/* Added at libpng-1.2.41 */
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-   /* Invert the alpha channel from opacity to transparency */
-   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
-      png_set_invert_alpha(png_ptr);
-#endif
-
-/* Added at libpng-1.2.41 */
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-   /* Expand grayscale image to RGB */
-   if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
-      png_set_gray_to_rgb(png_ptr);
-#endif
-
-/* Added at libpng-1.5.4 */
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-   if (transforms & PNG_TRANSFORM_EXPAND_16)
-      png_set_expand_16(png_ptr);
-#endif
-
-   /* We don't handle adding filler bytes */
-
-   /* We use png_read_image and rely on that for interlace handling, but we also
-    * call png_read_update_info therefore must turn on interlace handling now:
-    */
-   (void)png_set_interlace_handling(png_ptr);
-
-   /* Optional call to gamma correct and add the background to the palette
-    * and update info structure.  REQUIRED if you are expecting libpng to
-    * update the palette for you (i.e., you selected such a transform above).
-    */
-   png_read_update_info(png_ptr, info_ptr);
-
-   /* -------------- image transformations end here ------------------- */
-
-   png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
-   if (info_ptr->row_pointers == NULL)
-   {
-      png_uint_32 iptr;
-
-      info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
-          info_ptr->height * png_sizeof(png_bytep));
-      for (iptr=0; iptr<info_ptr->height; iptr++)
-         info_ptr->row_pointers[iptr] = NULL;
-
-      info_ptr->free_me |= PNG_FREE_ROWS;
-
-      for (row = 0; row < (int)info_ptr->height; row++)
-         info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
-            png_get_rowbytes(png_ptr, info_ptr));
-   }
-
-   png_read_image(png_ptr, info_ptr->row_pointers);
-   info_ptr->valid |= PNG_INFO_IDAT;
-
-   /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
-   png_read_end(png_ptr, info_ptr);
-
-   PNG_UNUSED(transforms)   /* Quiet compiler warnings */
-   PNG_UNUSED(params)
-
-}
-#endif /* PNG_INFO_IMAGE_SUPPORTED */
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED */
diff --git a/extern/libpng/include/pngrio.c b/extern/libpng/include/pngrio.c
deleted file mode 100644
index e9c381c5ba..0000000000
--- a/extern/libpng/include/pngrio.c
+++ /dev/null
@@ -1,176 +0,0 @@
-
-/* pngrio.c - functions for data input
- *
- * Last changed in libpng 1.5.0 [January 6, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * This file provides a location for all input.  Users who need
- * special handling are expected to write a function that has the same
- * arguments as this and performs a similar function, but that possibly
- * has a different input method.  Note that you shouldn't change this
- * function, but rather write a replacement function and then make
- * libpng use it at run time with png_set_read_fn(...).
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_READ_SUPPORTED
-
-/* Read the data from whatever input you are using.  The default routine
- * reads from a file pointer.  Note that this routine sometimes gets called
- * with very small lengths, so you should implement some kind of simple
- * buffering if you are using unbuffered reads.  This should never be asked
- * to read more then 64K on a 16 bit machine.
- */
-void /* PRIVATE */
-png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_debug1(4, "reading %d bytes", (int)length);
-
-   if (png_ptr->read_data_fn != NULL)
-      (*(png_ptr->read_data_fn))(png_ptr, data, length);
-
-   else
-      png_error(png_ptr, "Call to NULL read function");
-}
-
-#ifdef PNG_STDIO_SUPPORTED
-/* This is the function that does the actual reading of data.  If you are
- * not reading from a standard C stream, you should create a replacement
- * read_data function and use it at run time with png_set_read_fn(), rather
- * than changing the library.
- */
-#  ifndef USE_FAR_KEYWORD
-void PNGCBAPI
-png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_size_t check;
-
-   if (png_ptr == NULL)
-      return;
-
-   /* fread() returns 0 on error, so it is OK to store this in a png_size_t
-    * instead of an int, which is what fread() actually returns.
-    */
-   check = fread(data, 1, length, (png_FILE_p)png_ptr->io_ptr);
-
-   if (check != length)
-      png_error(png_ptr, "Read Error");
-}
-#  else
-/* This is the model-independent version. Since the standard I/O library
-   can't handle far buffers in the medium and small models, we have to copy
-   the data.
-*/
-
-#define NEAR_BUF_SIZE 1024
-#define MIN(a,b) (a <= b ? a : b)
-
-static void PNGCBAPI
-png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_size_t check;
-   png_byte *n_data;
-   png_FILE_p io_ptr;
-
-   if (png_ptr == NULL)
-      return;
-
-   /* Check if data really is near. If so, use usual code. */
-   n_data = (png_byte *)CVT_PTR_NOCHECK(data);
-   io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
-
-   if ((png_bytep)n_data == data)
-   {
-      check = fread(n_data, 1, length, io_ptr);
-   }
-
-   else
-   {
-      png_byte buf[NEAR_BUF_SIZE];
-      png_size_t read, remaining, err;
-      check = 0;
-      remaining = length;
-
-      do
-      {
-         read = MIN(NEAR_BUF_SIZE, remaining);
-         err = fread(buf, 1, read, io_ptr);
-         png_memcpy(data, buf, read); /* copy far buffer to near buffer */
-
-         if (err != read)
-            break;
-
-         else
-            check += err;
-
-         data += read;
-         remaining -= read;
-      }
-      while (remaining != 0);
-   }
-
-   if ((png_uint_32)check != (png_uint_32)length)
-      png_error(png_ptr, "read Error");
-}
-#  endif
-#endif
-
-/* This function allows the application to supply a new input function
- * for libpng if standard C streams aren't being used.
- *
- * This function takes as its arguments:
- *
- * png_ptr      - pointer to a png input data structure
- *
- * io_ptr       - pointer to user supplied structure containing info about
- *                the input functions.  May be NULL.
- *
- * read_data_fn - pointer to a new input function that takes as its
- *                arguments a pointer to a png_struct, a pointer to
- *                a location where input data can be stored, and a 32-bit
- *                unsigned int that is the number of bytes to be read.
- *                To exit and output any fatal error messages the new write
- *                function should call png_error(png_ptr, "Error msg").
- *                May be NULL, in which case libpng's default function will
- *                be used.
- */
-void PNGAPI
-png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
-   png_rw_ptr read_data_fn)
-{
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->io_ptr = io_ptr;
-
-#ifdef PNG_STDIO_SUPPORTED
-   if (read_data_fn != NULL)
-      png_ptr->read_data_fn = read_data_fn;
-
-   else
-      png_ptr->read_data_fn = png_default_read_data;
-#else
-   png_ptr->read_data_fn = read_data_fn;
-#endif
-
-   /* It is an error to write to a read device */
-   if (png_ptr->write_data_fn != NULL)
-   {
-      png_ptr->write_data_fn = NULL;
-      png_warning(png_ptr,
-          "Can't set both read_data_fn and write_data_fn in the"
-          " same structure");
-   }
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-   png_ptr->output_flush_fn = NULL;
-#endif
-}
-#endif /* PNG_READ_SUPPORTED */
diff --git a/extern/libpng/include/pngrtran.c b/extern/libpng/include/pngrtran.c
deleted file mode 100644
index 5561852860..0000000000
--- a/extern/libpng/include/pngrtran.c
+++ /dev/null
@@ -1,5032 +0,0 @@
-
-/* pngrtran.c - transforms the data in a row for PNG readers
- *
- * Last changed in libpng 1.5.10 [March 8, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * This file contains functions optionally called by an application
- * in order to tell libpng how to handle data when reading a PNG.
- * Transformations that are used in both reading and writing are
- * in pngtrans.c.
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_READ_SUPPORTED
-
-/* Set the action on getting a CRC error for an ancillary or critical chunk. */
-void PNGAPI
-png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
-{
-   png_debug(1, "in png_set_crc_action");
-
-   if (png_ptr == NULL)
-      return;
-
-   /* Tell libpng how we react to CRC errors in critical chunks */
-   switch (crit_action)
-   {
-      case PNG_CRC_NO_CHANGE:                        /* Leave setting as is */
-         break;
-
-      case PNG_CRC_WARN_USE:                               /* Warn/use data */
-         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
-         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
-         break;
-
-      case PNG_CRC_QUIET_USE:                             /* Quiet/use data */
-         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
-         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
-                           PNG_FLAG_CRC_CRITICAL_IGNORE;
-         break;
-
-      case PNG_CRC_WARN_DISCARD:    /* Not a valid action for critical data */
-         png_warning(png_ptr,
-            "Can't discard critical data on CRC error");
-      case PNG_CRC_ERROR_QUIT:                                /* Error/quit */
-
-      case PNG_CRC_DEFAULT:
-      default:
-         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
-         break;
-   }
-
-   /* Tell libpng how we react to CRC errors in ancillary chunks */
-   switch (ancil_action)
-   {
-      case PNG_CRC_NO_CHANGE:                       /* Leave setting as is */
-         break;
-
-      case PNG_CRC_WARN_USE:                              /* Warn/use data */
-         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
-         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
-         break;
-
-      case PNG_CRC_QUIET_USE:                            /* Quiet/use data */
-         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
-         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
-                           PNG_FLAG_CRC_ANCILLARY_NOWARN;
-         break;
-
-      case PNG_CRC_ERROR_QUIT:                               /* Error/quit */
-         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
-         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
-         break;
-
-      case PNG_CRC_WARN_DISCARD:                      /* Warn/discard data */
-
-      case PNG_CRC_DEFAULT:
-      default:
-         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
-         break;
-   }
-}
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-/* Handle alpha and tRNS via a background color */
-void PNGFAPI
-png_set_background_fixed(png_structp png_ptr,
-    png_const_color_16p background_color, int background_gamma_code,
-    int need_expand, png_fixed_point background_gamma)
-{
-   png_debug(1, "in png_set_background_fixed");
-
-   if (png_ptr == NULL)
-      return;
-
-   if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
-   {
-      png_warning(png_ptr, "Application must supply a known background gamma");
-      return;
-   }
-
-   png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA;
-   png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
-   png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-
-   png_memcpy(&(png_ptr->background), background_color,
-      png_sizeof(png_color_16));
-   png_ptr->background_gamma = background_gamma;
-   png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
-   if (need_expand)
-      png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
-   else
-      png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
-}
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_background(png_structp png_ptr,
-    png_const_color_16p background_color, int background_gamma_code,
-    int need_expand, double background_gamma)
-{
-   png_set_background_fixed(png_ptr, background_color, background_gamma_code,
-      need_expand, png_fixed(png_ptr, background_gamma, "png_set_background"));
-}
-#  endif  /* FLOATING_POINT */
-#endif /* READ_BACKGROUND */
-
-/* Scale 16-bit depth files to 8-bit depth.  If both of these are set then the
- * one that pngrtran does first (scale) happens.  This is necessary to allow the
- * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
- */
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-void PNGAPI
-png_set_scale_16(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_scale_16");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_SCALE_16_TO_8;
-}
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-/* Chop 16-bit depth files to 8-bit depth */
-void PNGAPI
-png_set_strip_16(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_strip_16");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_16_TO_8;
-}
-#endif
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-void PNGAPI
-png_set_strip_alpha(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_strip_alpha");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_STRIP_ALPHA;
-}
-#endif
-
-#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
-static png_fixed_point
-translate_gamma_flags(png_structp png_ptr, png_fixed_point output_gamma,
-   int is_screen)
-{
-   /* Check for flag values.  The main reason for having the old Mac value as a
-    * flag is that it is pretty near impossible to work out what the correct
-    * value is from Apple documentation - a working Mac system is needed to
-    * discover the value!
-    */
-   if (output_gamma == PNG_DEFAULT_sRGB ||
-      output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
-   {
-      /* If there is no sRGB support this just sets the gamma to the standard
-       * sRGB value.  (This is a side effect of using this function!)
-       */
-#     ifdef PNG_READ_sRGB_SUPPORTED
-         png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
-#     endif
-      if (is_screen)
-         output_gamma = PNG_GAMMA_sRGB;
-      else
-         output_gamma = PNG_GAMMA_sRGB_INVERSE;
-   }
-
-   else if (output_gamma == PNG_GAMMA_MAC_18 ||
-      output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
-   {
-      if (is_screen)
-         output_gamma = PNG_GAMMA_MAC_OLD;
-      else
-         output_gamma = PNG_GAMMA_MAC_INVERSE;
-   }
-
-   return output_gamma;
-}
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-static png_fixed_point
-convert_gamma_value(png_structp png_ptr, double output_gamma)
-{
-   /* The following silently ignores cases where fixed point (times 100,000)
-    * gamma values are passed to the floating point API.  This is safe and it
-    * means the fixed point constants work just fine with the floating point
-    * API.  The alternative would just lead to undetected errors and spurious
-    * bug reports.  Negative values fail inside the _fixed API unless they
-    * correspond to the flag values.
-    */
-   if (output_gamma > 0 && output_gamma < 128)
-      output_gamma *= PNG_FP_1;
-
-   /* This preserves -1 and -2 exactly: */
-   output_gamma = floor(output_gamma + .5);
-
-   if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
-      png_fixed_error(png_ptr, "gamma value");
-
-   return (png_fixed_point)output_gamma;
-}
-#  endif
-#endif /* READ_ALPHA_MODE || READ_GAMMA */
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-void PNGFAPI
-png_set_alpha_mode_fixed(png_structp png_ptr, int mode,
-   png_fixed_point output_gamma)
-{
-   int compose = 0;
-   png_fixed_point file_gamma;
-
-   png_debug(1, "in png_set_alpha_mode");
-
-   if (png_ptr == NULL)
-      return;
-
-   output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
-
-   /* Validate the value to ensure it is in a reasonable range. The value
-    * is expected to be 1 or greater, but this range test allows for some
-    * viewing correction values.  The intent is to weed out users of this API
-    * who use the inverse of the gamma value accidentally!  Since some of these
-    * values are reasonable this may have to be changed.
-    */
-   if (output_gamma < 70000 || output_gamma > 300000)
-      png_error(png_ptr, "output gamma out of expected range");
-
-   /* The default file gamma is the inverse of the output gamma; the output
-    * gamma may be changed below so get the file value first:
-    */
-   file_gamma = png_reciprocal(output_gamma);
-
-   /* There are really 8 possibilities here, composed of any combination
-    * of:
-    *
-    *    premultiply the color channels
-    *    do not encode non-opaque pixels
-    *    encode the alpha as well as the color channels
-    *
-    * The differences disappear if the input/output ('screen') gamma is 1.0,
-    * because then the encoding is a no-op and there is only the choice of
-    * premultiplying the color channels or not.
-    *
-    * png_set_alpha_mode and png_set_background interact because both use
-    * png_compose to do the work.  Calling both is only useful when
-    * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
-    * with a default gamma value.  Otherwise PNG_COMPOSE must not be set.
-    */
-   switch (mode)
-   {
-      case PNG_ALPHA_PNG:        /* default: png standard */
-         /* No compose, but it may be set by png_set_background! */
-         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
-         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-         break;
-
-      case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
-         compose = 1;
-         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
-         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-         /* The output is linear: */
-         output_gamma = PNG_FP_1;
-         break;
-
-      case PNG_ALPHA_OPTIMIZED:  /* associated, non-opaque pixels linear */
-         compose = 1;
-         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
-         png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
-         /* output_gamma records the encoding of opaque pixels! */
-         break;
-
-      case PNG_ALPHA_BROKEN:     /* associated, non-linear, alpha encoded */
-         compose = 1;
-         png_ptr->transformations |= PNG_ENCODE_ALPHA;
-         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-         break;
-
-      default:
-         png_error(png_ptr, "invalid alpha mode");
-   }
-
-   /* Only set the default gamma if the file gamma has not been set (this has
-    * the side effect that the gamma in a second call to png_set_alpha_mode will
-    * be ignored.)
-    */
-   if (png_ptr->gamma == 0)
-      png_ptr->gamma = file_gamma;
-
-   /* But always set the output gamma: */
-   png_ptr->screen_gamma = output_gamma;
-
-   /* Finally, if pre-multiplying, set the background fields to achieve the
-    * desired result.
-    */
-   if (compose)
-   {
-      /* And obtain alpha pre-multiplication by composing on black: */
-      png_memset(&png_ptr->background, 0, sizeof png_ptr->background);
-      png_ptr->background_gamma = png_ptr->gamma; /* just in case */
-      png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
-      png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
-
-      if (png_ptr->transformations & PNG_COMPOSE)
-         png_error(png_ptr,
-            "conflicting calls to set alpha mode and background");
-
-      png_ptr->transformations |= PNG_COMPOSE;
-   }
-
-   /* New API, make sure apps call the correct initializers: */
-   png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
-}
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_alpha_mode(png_structp png_ptr, int mode, double output_gamma)
-{
-   png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
-      output_gamma));
-}
-#  endif
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-/* Dither file to 8-bit.  Supply a palette, the current number
- * of elements in the palette, the maximum number of elements
- * allowed, and a histogram if possible.  If the current number
- * of colors is greater then the maximum number, the palette will be
- * modified to fit in the maximum number.  "full_quantize" indicates
- * whether we need a quantizing cube set up for RGB images, or if we
- * simply are reducing the number of colors in a paletted image.
- */
-
-typedef struct png_dsort_struct
-{
-   struct png_dsort_struct FAR * next;
-   png_byte left;
-   png_byte right;
-} png_dsort;
-typedef png_dsort FAR *       png_dsortp;
-typedef png_dsort FAR * FAR * png_dsortpp;
-
-void PNGAPI
-png_set_quantize(png_structp png_ptr, png_colorp palette,
-    int num_palette, int maximum_colors, png_const_uint_16p histogram,
-    int full_quantize)
-{
-   png_debug(1, "in png_set_quantize");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_QUANTIZE;
-
-   if (!full_quantize)
-   {
-      int i;
-
-      png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
-          (png_uint_32)(num_palette * png_sizeof(png_byte)));
-      for (i = 0; i < num_palette; i++)
-         png_ptr->quantize_index[i] = (png_byte)i;
-   }
-
-   if (num_palette > maximum_colors)
-   {
-      if (histogram != NULL)
-      {
-         /* This is easy enough, just throw out the least used colors.
-          * Perhaps not the best solution, but good enough.
-          */
-
-         int i;
-
-         /* Initialize an array to sort colors */
-         png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
-             (png_uint_32)(num_palette * png_sizeof(png_byte)));
-
-         /* Initialize the quantize_sort array */
-         for (i = 0; i < num_palette; i++)
-            png_ptr->quantize_sort[i] = (png_byte)i;
-
-         /* Find the least used palette entries by starting a
-          * bubble sort, and running it until we have sorted
-          * out enough colors.  Note that we don't care about
-          * sorting all the colors, just finding which are
-          * least used.
-          */
-
-         for (i = num_palette - 1; i >= maximum_colors; i--)
-         {
-            int done; /* To stop early if the list is pre-sorted */
-            int j;
-
-            done = 1;
-            for (j = 0; j < i; j++)
-            {
-               if (histogram[png_ptr->quantize_sort[j]]
-                   < histogram[png_ptr->quantize_sort[j + 1]])
-               {
-                  png_byte t;
-
-                  t = png_ptr->quantize_sort[j];
-                  png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
-                  png_ptr->quantize_sort[j + 1] = t;
-                  done = 0;
-               }
-            }
-
-            if (done)
-               break;
-         }
-
-         /* Swap the palette around, and set up a table, if necessary */
-         if (full_quantize)
-         {
-            int j = num_palette;
-
-            /* Put all the useful colors within the max, but don't
-             * move the others.
-             */
-            for (i = 0; i < maximum_colors; i++)
-            {
-               if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
-               {
-                  do
-                     j--;
-                  while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
-
-                  palette[i] = palette[j];
-               }
-            }
-         }
-         else
-         {
-            int j = num_palette;
-
-            /* Move all the used colors inside the max limit, and
-             * develop a translation table.
-             */
-            for (i = 0; i < maximum_colors; i++)
-            {
-               /* Only move the colors we need to */
-               if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
-               {
-                  png_color tmp_color;
-
-                  do
-                     j--;
-                  while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
-
-                  tmp_color = palette[j];
-                  palette[j] = palette[i];
-                  palette[i] = tmp_color;
-                  /* Indicate where the color went */
-                  png_ptr->quantize_index[j] = (png_byte)i;
-                  png_ptr->quantize_index[i] = (png_byte)j;
-               }
-            }
-
-            /* Find closest color for those colors we are not using */
-            for (i = 0; i < num_palette; i++)
-            {
-               if ((int)png_ptr->quantize_index[i] >= maximum_colors)
-               {
-                  int min_d, k, min_k, d_index;
-
-                  /* Find the closest color to one we threw out */
-                  d_index = png_ptr->quantize_index[i];
-                  min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
-                  for (k = 1, min_k = 0; k < maximum_colors; k++)
-                  {
-                     int d;
-
-                     d = PNG_COLOR_DIST(palette[d_index], palette[k]);
-
-                     if (d < min_d)
-                     {
-                        min_d = d;
-                        min_k = k;
-                     }
-                  }
-                  /* Point to closest color */
-                  png_ptr->quantize_index[i] = (png_byte)min_k;
-               }
-            }
-         }
-         png_free(png_ptr, png_ptr->quantize_sort);
-         png_ptr->quantize_sort = NULL;
-      }
-      else
-      {
-         /* This is much harder to do simply (and quickly).  Perhaps
-          * we need to go through a median cut routine, but those
-          * don't always behave themselves with only a few colors
-          * as input.  So we will just find the closest two colors,
-          * and throw out one of them (chosen somewhat randomly).
-          * [We don't understand this at all, so if someone wants to
-          *  work on improving it, be our guest - AED, GRP]
-          */
-         int i;
-         int max_d;
-         int num_new_palette;
-         png_dsortp t;
-         png_dsortpp hash;
-
-         t = NULL;
-
-         /* Initialize palette index arrays */
-         png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
-             (png_uint_32)(num_palette * png_sizeof(png_byte)));
-         png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
-             (png_uint_32)(num_palette * png_sizeof(png_byte)));
-
-         /* Initialize the sort array */
-         for (i = 0; i < num_palette; i++)
-         {
-            png_ptr->index_to_palette[i] = (png_byte)i;
-            png_ptr->palette_to_index[i] = (png_byte)i;
-         }
-
-         hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 *
-             png_sizeof(png_dsortp)));
-
-         num_new_palette = num_palette;
-
-         /* Initial wild guess at how far apart the farthest pixel
-          * pair we will be eliminating will be.  Larger
-          * numbers mean more areas will be allocated, Smaller
-          * numbers run the risk of not saving enough data, and
-          * having to do this all over again.
-          *
-          * I have not done extensive checking on this number.
-          */
-         max_d = 96;
-
-         while (num_new_palette > maximum_colors)
-         {
-            for (i = 0; i < num_new_palette - 1; i++)
-            {
-               int j;
-
-               for (j = i + 1; j < num_new_palette; j++)
-               {
-                  int d;
-
-                  d = PNG_COLOR_DIST(palette[i], palette[j]);
-
-                  if (d <= max_d)
-                  {
-
-                     t = (png_dsortp)png_malloc_warn(png_ptr,
-                         (png_uint_32)(png_sizeof(png_dsort)));
-
-                     if (t == NULL)
-                         break;
-
-                     t->next = hash[d];
-                     t->left = (png_byte)i;
-                     t->right = (png_byte)j;
-                     hash[d] = t;
-                  }
-               }
-               if (t == NULL)
-                  break;
-            }
-
-            if (t != NULL)
-            for (i = 0; i <= max_d; i++)
-            {
-               if (hash[i] != NULL)
-               {
-                  png_dsortp p;
-
-                  for (p = hash[i]; p; p = p->next)
-                  {
-                     if ((int)png_ptr->index_to_palette[p->left]
-                         < num_new_palette &&
-                         (int)png_ptr->index_to_palette[p->right]
-                         < num_new_palette)
-                     {
-                        int j, next_j;
-
-                        if (num_new_palette & 0x01)
-                        {
-                           j = p->left;
-                           next_j = p->right;
-                        }
-                        else
-                        {
-                           j = p->right;
-                           next_j = p->left;
-                        }
-
-                        num_new_palette--;
-                        palette[png_ptr->index_to_palette[j]]
-                            = palette[num_new_palette];
-                        if (!full_quantize)
-                        {
-                           int k;
-
-                           for (k = 0; k < num_palette; k++)
-                           {
-                              if (png_ptr->quantize_index[k] ==
-                                  png_ptr->index_to_palette[j])
-                                 png_ptr->quantize_index[k] =
-                                     png_ptr->index_to_palette[next_j];
-
-                              if ((int)png_ptr->quantize_index[k] ==
-                                  num_new_palette)
-                                 png_ptr->quantize_index[k] =
-                                     png_ptr->index_to_palette[j];
-                           }
-                        }
-
-                        png_ptr->index_to_palette[png_ptr->palette_to_index
-                            [num_new_palette]] = png_ptr->index_to_palette[j];
-
-                        png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
-                            = png_ptr->palette_to_index[num_new_palette];
-
-                        png_ptr->index_to_palette[j] =
-                            (png_byte)num_new_palette;
-
-                        png_ptr->palette_to_index[num_new_palette] =
-                            (png_byte)j;
-                     }
-                     if (num_new_palette <= maximum_colors)
-                        break;
-                  }
-                  if (num_new_palette <= maximum_colors)
-                     break;
-               }
-            }
-
-            for (i = 0; i < 769; i++)
-            {
-               if (hash[i] != NULL)
-               {
-                  png_dsortp p = hash[i];
-                  while (p)
-                  {
-                     t = p->next;
-                     png_free(png_ptr, p);
-                     p = t;
-                  }
-               }
-               hash[i] = 0;
-            }
-            max_d += 96;
-         }
-         png_free(png_ptr, hash);
-         png_free(png_ptr, png_ptr->palette_to_index);
-         png_free(png_ptr, png_ptr->index_to_palette);
-         png_ptr->palette_to_index = NULL;
-         png_ptr->index_to_palette = NULL;
-      }
-      num_palette = maximum_colors;
-   }
-   if (png_ptr->palette == NULL)
-   {
-      png_ptr->palette = palette;
-   }
-   png_ptr->num_palette = (png_uint_16)num_palette;
-
-   if (full_quantize)
-   {
-      int i;
-      png_bytep distance;
-      int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
-          PNG_QUANTIZE_BLUE_BITS;
-      int num_red = (1 << PNG_QUANTIZE_RED_BITS);
-      int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
-      int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);
-      png_size_t num_entries = ((png_size_t)1 << total_bits);
-
-      png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr,
-          (png_uint_32)(num_entries * png_sizeof(png_byte)));
-
-      distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
-          png_sizeof(png_byte)));
-
-      png_memset(distance, 0xff, num_entries * png_sizeof(png_byte));
-
-      for (i = 0; i < num_palette; i++)
-      {
-         int ir, ig, ib;
-         int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
-         int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
-         int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS));
-
-         for (ir = 0; ir < num_red; ir++)
-         {
-            /* int dr = abs(ir - r); */
-            int dr = ((ir > r) ? ir - r : r - ir);
-            int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS +
-                PNG_QUANTIZE_GREEN_BITS));
-
-            for (ig = 0; ig < num_green; ig++)
-            {
-               /* int dg = abs(ig - g); */
-               int dg = ((ig > g) ? ig - g : g - ig);
-               int dt = dr + dg;
-               int dm = ((dr > dg) ? dr : dg);
-               int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS);
-
-               for (ib = 0; ib < num_blue; ib++)
-               {
-                  int d_index = index_g | ib;
-                  /* int db = abs(ib - b); */
-                  int db = ((ib > b) ? ib - b : b - ib);
-                  int dmax = ((dm > db) ? dm : db);
-                  int d = dmax + dt + db;
-
-                  if (d < (int)distance[d_index])
-                  {
-                     distance[d_index] = (png_byte)d;
-                     png_ptr->palette_lookup[d_index] = (png_byte)i;
-                  }
-               }
-            }
-         }
-      }
-
-      png_free(png_ptr, distance);
-   }
-}
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-void PNGFAPI
-png_set_gamma_fixed(png_structp png_ptr, png_fixed_point scrn_gamma,
-   png_fixed_point file_gamma)
-{
-   png_debug(1, "in png_set_gamma_fixed");
-
-   if (png_ptr == NULL)
-      return;
-
-   /* New in libpng-1.5.4 - reserve particular negative values as flags. */
-   scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
-   file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
-
-#if PNG_LIBPNG_VER >= 10600
-   /* Checking the gamma values for being >0 was added in 1.5.4 along with the
-    * premultiplied alpha support; this actually hides an undocumented feature
-    * of the previous implementation which allowed gamma processing to be
-    * disabled in background handling.  There is no evidence (so far) that this
-    * was being used; however, png_set_background itself accepted and must still
-    * accept '0' for the gamma value it takes, because it isn't always used.
-    *
-    * Since this is an API change (albeit a very minor one that removes an
-    * undocumented API feature) it will not be made until libpng-1.6.0.
-    */
-   if (file_gamma <= 0)
-      png_error(png_ptr, "invalid file gamma in png_set_gamma");
-
-   if (scrn_gamma <= 0)
-      png_error(png_ptr, "invalid screen gamma in png_set_gamma");
-#endif
-
-   /* Set the gamma values unconditionally - this overrides the value in the PNG
-    * file if a gAMA chunk was present.  png_set_alpha_mode provides a
-    * different, easier, way to default the file gamma.
-    */
-   png_ptr->gamma = file_gamma;
-   png_ptr->screen_gamma = scrn_gamma;
-}
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
-{
-   png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
-      convert_gamma_value(png_ptr, file_gamma));
-}
-#  endif /* FLOATING_POINT_SUPPORTED */
-#endif /* READ_GAMMA */
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* Expand paletted images to RGB, expand grayscale images of
- * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
- * to alpha channels.
- */
-void PNGAPI
-png_set_expand(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_expand");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
-   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
-}
-
-/* GRR 19990627:  the following three functions currently are identical
- *  to png_set_expand().  However, it is entirely reasonable that someone
- *  might wish to expand an indexed image to RGB but *not* expand a single,
- *  fully transparent palette entry to a full alpha channel--perhaps instead
- *  convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
- *  the transparent color with a particular RGB value, or drop tRNS entirely.
- *  IOW, a future version of the library may make the transformations flag
- *  a bit more fine-grained, with separate bits for each of these three
- *  functions.
- *
- *  More to the point, these functions make it obvious what libpng will be
- *  doing, whereas "expand" can (and does) mean any number of things.
- *
- *  GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
- *  to expand only the sample depth but not to expand the tRNS to alpha
- *  and its name was changed to png_set_expand_gray_1_2_4_to_8().
- */
-
-/* Expand paletted images to RGB. */
-void PNGAPI
-png_set_palette_to_rgb(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_palette_to_rgb");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
-   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
-}
-
-/* Expand grayscale images of less than 8-bit depth to 8 bits. */
-void PNGAPI
-png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_EXPAND;
-   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
-}
-
-
-
-/* Expand tRNS chunks to alpha channels. */
-void PNGAPI
-png_set_tRNS_to_alpha(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_tRNS_to_alpha");
-
-   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
-   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
-}
-#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
- * it may not work correctly.)
- */
-void PNGAPI
-png_set_expand_16(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_expand_16");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
-   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
-
-   /* New API, make sure apps call the correct initializers: */
-   png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
-}
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-void PNGAPI
-png_set_gray_to_rgb(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_gray_to_rgb");
-
-   if (png_ptr != NULL)
-   {
-      /* Because rgb must be 8 bits or more: */
-      png_set_expand_gray_1_2_4_to_8(png_ptr);
-      png_ptr->transformations |= PNG_GRAY_TO_RGB;
-      png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
-   }
-}
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-void PNGFAPI
-png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
-    png_fixed_point red, png_fixed_point green)
-{
-   png_debug(1, "in png_set_rgb_to_gray");
-
-   if (png_ptr == NULL)
-      return;
-
-   switch(error_action)
-   {
-      case PNG_ERROR_ACTION_NONE:
-         png_ptr->transformations |= PNG_RGB_TO_GRAY;
-         break;
-
-      case PNG_ERROR_ACTION_WARN:
-         png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
-         break;
-
-      case PNG_ERROR_ACTION_ERROR:
-         png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
-         break;
-
-      default:
-         png_error(png_ptr, "invalid error action to rgb_to_gray");
-         break;
-   }
-   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-#ifdef PNG_READ_EXPAND_SUPPORTED
-      png_ptr->transformations |= PNG_EXPAND;
-#else
-   {
-      png_warning(png_ptr,
-        "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
-
-      png_ptr->transformations &= ~PNG_RGB_TO_GRAY;
-   }
-#endif
-   {
-      if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
-      {
-         png_uint_16 red_int, green_int;
-
-         /* NOTE: this calculation does not round, but this behavior is retained
-          * for consistency, the inaccuracy is very small.  The code here always
-          * overwrites the coefficients, regardless of whether they have been
-          * defaulted or set already.
-          */
-         red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
-         green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
-
-         png_ptr->rgb_to_gray_red_coeff   = red_int;
-         png_ptr->rgb_to_gray_green_coeff = green_int;
-         png_ptr->rgb_to_gray_coefficients_set = 1;
-      }
-
-      else
-      {
-         if (red >= 0 && green >= 0)
-            png_warning(png_ptr,
-               "ignoring out of range rgb_to_gray coefficients");
-
-         /* Use the defaults, from the cHRM chunk if set, else the historical
-          * values which are close to the sRGB/HDTV/ITU-Rec 709 values.  See
-          * png_do_rgb_to_gray for more discussion of the values.  In this case
-          * the coefficients are not marked as 'set' and are not overwritten if
-          * something has already provided a default.
-          */
-         if (png_ptr->rgb_to_gray_red_coeff == 0 &&
-            png_ptr->rgb_to_gray_green_coeff == 0)
-         {
-            png_ptr->rgb_to_gray_red_coeff   = 6968;
-            png_ptr->rgb_to_gray_green_coeff = 23434;
-            /* png_ptr->rgb_to_gray_blue_coeff  = 2366; */
-         }
-      }
-   }
-}
-
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-/* Convert a RGB image to a grayscale of the same width.  This allows us,
- * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
- */
-
-void PNGAPI
-png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
-   double green)
-{
-   if (png_ptr == NULL)
-      return;
-
-   png_set_rgb_to_gray_fixed(png_ptr, error_action,
-      png_fixed(png_ptr, red, "rgb to gray red coefficient"),
-      png_fixed(png_ptr, green, "rgb to gray green coefficient"));
-}
-#endif /* FLOATING POINT */
-
-#endif
-
-#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
-    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
-void PNGAPI
-png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
-    read_user_transform_fn)
-{
-   png_debug(1, "in png_set_read_user_transform_fn");
-
-   if (png_ptr == NULL)
-      return;
-
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-   png_ptr->transformations |= PNG_USER_TRANSFORM;
-   png_ptr->read_user_transform_fn = read_user_transform_fn;
-#endif
-}
-#endif
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-#ifdef PNG_READ_GAMMA_SUPPORTED
-/* In the case of gamma transformations only do transformations on images where
- * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
- * slows things down slightly, and also needlessly introduces small errors.
- */
-static int /* PRIVATE */
-png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
-{
-   /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
-    * correction as a difference of the overall transform from 1.0
-    *
-    * We want to compare the threshold with s*f - 1, if we get
-    * overflow here it is because of wacky gamma values so we
-    * turn on processing anyway.
-    */
-   png_fixed_point gtest;
-   return !png_muldiv(&gtest, screen_gamma, file_gamma, PNG_FP_1) ||
-       png_gamma_significant(gtest);
-}
-#endif
-
-/* Initialize everything needed for the read.  This includes modifying
- * the palette.
- */
-
-/*For the moment 'png_init_palette_transformations' and
- * 'png_init_rgb_transformations' only do some flag canceling optimizations.
- * The intent is that these two routines should have palette or rgb operations
- * extracted from 'png_init_read_transformations'.
- */
-static void /* PRIVATE */
-png_init_palette_transformations(png_structp png_ptr)
-{
-   /* Called to handle the (input) palette case.  In png_do_read_transformations
-    * the first step is to expand the palette if requested, so this code must
-    * take care to only make changes that are invariant with respect to the
-    * palette expansion, or only do them if there is no expansion.
-    *
-    * STRIP_ALPHA has already been handled in the caller (by setting num_trans
-    * to 0.)
-    */
-   int input_has_alpha = 0;
-   int input_has_transparency = 0;
-
-   if (png_ptr->num_trans > 0)
-   {
-      int i;
-
-      /* Ignore if all the entries are opaque (unlikely!) */
-      for (i=0; i<png_ptr->num_trans; ++i)
-         if (png_ptr->trans_alpha[i] == 255)
-            continue;
-         else if (png_ptr->trans_alpha[i] == 0)
-            input_has_transparency = 1;
-         else
-            input_has_alpha = 1;
-   }
-
-   /* If no alpha we can optimize. */
-   if (!input_has_alpha)
-   {
-      /* Any alpha means background and associative alpha processing is
-       * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
-       * and ENCODE_ALPHA are irrelevant.
-       */
-      png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
-      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-
-      if (!input_has_transparency)
-         png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
-   }
-
-#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
-   /* png_set_background handling - deals with the complexity of whether the
-    * background color is in the file format or the screen format in the case
-    * where an 'expand' will happen.
-    */
-
-   /* The following code cannot be entered in the alpha pre-multiplication case
-    * because PNG_BACKGROUND_EXPAND is cancelled below.
-    */
-   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-       (png_ptr->transformations & PNG_EXPAND))
-   {
-      {
-         png_ptr->background.red   =
-             png_ptr->palette[png_ptr->background.index].red;
-         png_ptr->background.green =
-             png_ptr->palette[png_ptr->background.index].green;
-         png_ptr->background.blue  =
-             png_ptr->palette[png_ptr->background.index].blue;
-
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-        if (png_ptr->transformations & PNG_INVERT_ALPHA)
-        {
-           if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
-           {
-              /* Invert the alpha channel (in tRNS) unless the pixels are
-               * going to be expanded, in which case leave it for later
-               */
-              int i, istop = png_ptr->num_trans;
-
-              for (i=0; i<istop; i++)
-                 png_ptr->trans_alpha[i] = (png_byte)(255 -
-                    png_ptr->trans_alpha[i]);
-           }
-        }
-#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
-      }
-   } /* background expand and (therefore) no alpha association. */
-#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
-}
-
-static void /* PRIVATE */
-png_init_rgb_transformations(png_structp png_ptr)
-{
-   /* Added to libpng-1.5.4: check the color type to determine whether there
-    * is any alpha or transparency in the image and simply cancel the
-    * background and alpha mode stuff if there isn't.
-    */
-   int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
-   int input_has_transparency = png_ptr->num_trans > 0;
-
-   /* If no alpha we can optimize. */
-   if (!input_has_alpha)
-   {
-      /* Any alpha means background and associative alpha processing is
-       * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
-       * and ENCODE_ALPHA are irrelevant.
-       */
-#     ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
-         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-#     endif
-
-      if (!input_has_transparency)
-         png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
-   }
-
-#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
-   /* png_set_background handling - deals with the complexity of whether the
-    * background color is in the file format or the screen format in the case
-    * where an 'expand' will happen.
-    */
-
-   /* The following code cannot be entered in the alpha pre-multiplication case
-    * because PNG_BACKGROUND_EXPAND is cancelled below.
-    */
-   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-       (png_ptr->transformations & PNG_EXPAND) &&
-       !(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
-       /* i.e., GRAY or GRAY_ALPHA */
-   {
-      {
-         /* Expand background and tRNS chunks */
-         int gray = png_ptr->background.gray;
-         int trans_gray = png_ptr->trans_color.gray;
-
-         switch (png_ptr->bit_depth)
-         {
-            case 1:
-               gray *= 0xff;
-               trans_gray *= 0xff;
-               break;
-
-            case 2:
-               gray *= 0x55;
-               trans_gray *= 0x55;
-               break;
-
-            case 4:
-               gray *= 0x11;
-               trans_gray *= 0x11;
-               break;
-
-            default:
-
-            case 8:
-               /* Already 8 bits, fall through */
-
-            case 16:
-               /* Already a full 16 bits */
-               break;
-         }
-
-         png_ptr->background.red = png_ptr->background.green =
-            png_ptr->background.blue = (png_uint_16)gray;
-
-         if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
-         {
-            png_ptr->trans_color.red = png_ptr->trans_color.green =
-               png_ptr->trans_color.blue = (png_uint_16)trans_gray;
-         }
-      }
-   } /* background expand and (therefore) no alpha association. */
-#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
-}
-
-void /* PRIVATE */
-png_init_read_transformations(png_structp png_ptr)
-{
-   png_debug(1, "in png_init_read_transformations");
-
-   /* This internal function is called from png_read_start_row in pngrutil.c
-    * and it is called before the 'rowbytes' calculation is done, so the code
-    * in here can change or update the transformations flags.
-    *
-    * First do updates that do not depend on the details of the PNG image data
-    * being processed.
-    */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
-    * png_set_alpha_mode and this is another source for a default file gamma so
-    * the test needs to be performed later - here.  In addition prior to 1.5.4
-    * the tests were repeated for the PALETTE color type here - this is no
-    * longer necessary (and doesn't seem to have been necessary before.)
-    */
-   {
-      /* The following temporary indicates if overall gamma correction is
-       * required.
-       */
-      int gamma_correction = 0;
-
-      if (png_ptr->gamma != 0) /* has been set */
-      {
-         if (png_ptr->screen_gamma != 0) /* screen set too */
-            gamma_correction = png_gamma_threshold(png_ptr->gamma,
-               png_ptr->screen_gamma);
-
-         else
-            /* Assume the output matches the input; a long time default behavior
-             * of libpng, although the standard has nothing to say about this.
-             */
-            png_ptr->screen_gamma = png_reciprocal(png_ptr->gamma);
-      }
-
-      else if (png_ptr->screen_gamma != 0)
-         /* The converse - assume the file matches the screen, note that this
-          * perhaps undesireable default can (from 1.5.4) be changed by calling
-          * png_set_alpha_mode (even if the alpha handling mode isn't required
-          * or isn't changed from the default.)
-          */
-         png_ptr->gamma = png_reciprocal(png_ptr->screen_gamma);
-
-      else /* neither are set */
-         /* Just in case the following prevents any processing - file and screen
-          * are both assumed to be linear and there is no way to introduce a
-          * third gamma value other than png_set_background with 'UNIQUE', and,
-          * prior to 1.5.4
-          */
-         png_ptr->screen_gamma = png_ptr->gamma = PNG_FP_1;
-
-      /* Now turn the gamma transformation on or off as appropriate.  Notice
-       * that PNG_GAMMA just refers to the file->screen correction.  Alpha
-       * composition may independently cause gamma correction because it needs
-       * linear data (e.g. if the file has a gAMA chunk but the screen gamma
-       * hasn't been specified.)  In any case this flag may get turned off in
-       * the code immediately below if the transform can be handled outside the
-       * row loop.
-       */
-      if (gamma_correction)
-         png_ptr->transformations |= PNG_GAMMA;
-
-      else
-         png_ptr->transformations &= ~PNG_GAMMA;
-   }
-#endif
-
-   /* Certain transformations have the effect of preventing other
-    * transformations that happen afterward in png_do_read_transformations,
-    * resolve the interdependencies here.  From the code of
-    * png_do_read_transformations the order is:
-    *
-    *  1) PNG_EXPAND (including PNG_EXPAND_tRNS)
-    *  2) PNG_STRIP_ALPHA (if no compose)
-    *  3) PNG_RGB_TO_GRAY
-    *  4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
-    *  5) PNG_COMPOSE
-    *  6) PNG_GAMMA
-    *  7) PNG_STRIP_ALPHA (if compose)
-    *  8) PNG_ENCODE_ALPHA
-    *  9) PNG_SCALE_16_TO_8
-    * 10) PNG_16_TO_8
-    * 11) PNG_QUANTIZE (converts to palette)
-    * 12) PNG_EXPAND_16
-    * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
-    * 14) PNG_INVERT_MONO
-    * 15) PNG_SHIFT
-    * 16) PNG_PACK
-    * 17) PNG_BGR
-    * 18) PNG_PACKSWAP
-    * 19) PNG_FILLER (includes PNG_ADD_ALPHA)
-    * 20) PNG_INVERT_ALPHA
-    * 21) PNG_SWAP_ALPHA
-    * 22) PNG_SWAP_BYTES
-    * 23) PNG_USER_TRANSFORM [must be last]
-    */
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      !(png_ptr->transformations & PNG_COMPOSE))
-   {
-      /* Stripping the alpha channel happens immediately after the 'expand'
-       * transformations, before all other transformation, so it cancels out
-       * the alpha handling.  It has the side effect negating the effect of
-       * PNG_EXPAND_tRNS too:
-       */
-      png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
-         PNG_EXPAND_tRNS);
-      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-
-      /* Kill the tRNS chunk itself too.  Prior to 1.5.4 this did not happen
-       * so transparency information would remain just so long as it wasn't
-       * expanded.  This produces unexpected API changes if the set of things
-       * that do PNG_EXPAND_tRNS changes (perfectly possible given the
-       * documentation - which says ask for what you want, accept what you
-       * get.)  This makes the behavior consistent from 1.5.4:
-       */
-      png_ptr->num_trans = 0;
-   }
-#endif /* STRIP_ALPHA supported, no COMPOSE */
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-   /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
-    * settings will have no effect.
-    */
-   if (!png_gamma_significant(png_ptr->screen_gamma))
-   {
-      png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
-      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
-   }
-#endif
-
-#if defined(PNG_READ_EXPAND_SUPPORTED) && \
-   defined(PNG_READ_BACKGROUND_SUPPORTED) && \
-   defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
-   /* Detect gray background and attempt to enable optimization for
-    * gray --> RGB case.
-    *
-    * Note:  if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
-    * RGB_ALPHA (in which case need_expand is superfluous anyway), the
-    * background color might actually be gray yet not be flagged as such.
-    * This is not a problem for the current code, which uses
-    * PNG_BACKGROUND_IS_GRAY only to decide when to do the
-    * png_do_gray_to_rgb() transformation.
-    *
-    * TODO: this code needs to be revised to avoid the complexity and
-    * interdependencies.  The color type of the background should be recorded in
-    * png_set_background, along with the bit depth, then the code has a record
-    * of exactly what color space the background is currently in.
-    */
-   if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
-   {
-      /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
-       * the file was grayscale the background value is gray.
-       */
-      if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
-         png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
-   }
-
-   else if (png_ptr->transformations & PNG_COMPOSE)
-   {
-      /* PNG_COMPOSE: png_set_background was called with need_expand false,
-       * so the color is in the color space of the output or png_set_alpha_mode
-       * was called and the color is black.  Ignore RGB_TO_GRAY because that
-       * happens before GRAY_TO_RGB.
-       */
-      if (png_ptr->transformations & PNG_GRAY_TO_RGB)
-      {
-         if (png_ptr->background.red == png_ptr->background.green &&
-             png_ptr->background.red == png_ptr->background.blue)
-         {
-            png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
-            png_ptr->background.gray = png_ptr->background.red;
-         }
-      }
-   }
-#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED (etc) */
-
-   /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
-    * can be performed directly on the palette, and some (such as rgb to gray)
-    * can be optimized inside the palette.  This is particularly true of the
-    * composite (background and alpha) stuff, which can be pretty much all done
-    * in the palette even if the result is expanded to RGB or gray afterward.
-    *
-    * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
-    * earlier and the palette stuff is actually handled on the first row.  This
-    * leads to the reported bug that the palette returned by png_get_PLTE is not
-    * updated.
-    */
-   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      png_init_palette_transformations(png_ptr);
-
-   else
-      png_init_rgb_transformations(png_ptr);
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
-   defined(PNG_READ_EXPAND_16_SUPPORTED)
-   if ((png_ptr->transformations & PNG_EXPAND_16) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-      png_ptr->bit_depth != 16)
-   {
-      /* TODO: fix this.  Because the expand_16 operation is after the compose
-       * handling the background color must be 8, not 16, bits deep, but the
-       * application will supply a 16-bit value so reduce it here.
-       *
-       * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
-       * present, so that case is ok (until do_expand_16 is moved.)
-       *
-       * NOTE: this discards the low 16 bits of the user supplied background
-       * color, but until expand_16 works properly there is no choice!
-       */
-#     define CHOP(x) (x)=((png_uint_16)(((png_uint_32)(x)*255+32895) >> 16))
-      CHOP(png_ptr->background.red);
-      CHOP(png_ptr->background.green);
-      CHOP(png_ptr->background.blue);
-      CHOP(png_ptr->background.gray);
-#     undef CHOP
-   }
-#endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
-   (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
-   defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
-   if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-      png_ptr->bit_depth == 16)
-   {
-      /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
-       * component this will also happen after PNG_COMPOSE and so the background
-       * color must be pre-expanded here.
-       *
-       * TODO: fix this too.
-       */
-      png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
-      png_ptr->background.green =
-         (png_uint_16)(png_ptr->background.green * 257);
-      png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
-      png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
-   }
-#endif
-
-   /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
-    * background support (see the comments in scripts/pnglibconf.dfa), this
-    * allows pre-multiplication of the alpha channel to be implemented as
-    * compositing on black.  This is probably sub-optimal and has been done in
-    * 1.5.4 betas simply to enable external critique and testing (i.e. to
-    * implement the new API quickly, without lots of internal changes.)
-    */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-#  ifdef PNG_READ_BACKGROUND_SUPPORTED
-      /* Includes ALPHA_MODE */
-      png_ptr->background_1 = png_ptr->background;
-#  endif
-
-   /* This needs to change - in the palette image case a whole set of tables are
-    * built when it would be quicker to just calculate the correct value for
-    * each palette entry directly.  Also, the test is too tricky - why check
-    * PNG_RGB_TO_GRAY if PNG_GAMMA is not set?  The answer seems to be that
-    * PNG_GAMMA is cancelled even if the gamma is known?  The test excludes the
-    * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
-    * the gamma tables will not be built even if composition is required on a
-    * gamma encoded value.
-    *
-    * In 1.5.4 this is addressed below by an additional check on the individual
-    * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
-    * tables.
-    */
-   if ((png_ptr->transformations & PNG_GAMMA)
-      || ((png_ptr->transformations & PNG_RGB_TO_GRAY)
-         && (png_gamma_significant(png_ptr->gamma) ||
-            png_gamma_significant(png_ptr->screen_gamma)))
-      || ((png_ptr->transformations & PNG_COMPOSE)
-         && (png_gamma_significant(png_ptr->gamma)
-            || png_gamma_significant(png_ptr->screen_gamma)
-#  ifdef PNG_READ_BACKGROUND_SUPPORTED
-            || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE
-               && png_gamma_significant(png_ptr->background_gamma))
-#  endif
-      )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA)
-         && png_gamma_significant(png_ptr->screen_gamma))
-      )
-   {
-      png_build_gamma_table(png_ptr, png_ptr->bit_depth);
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-      if (png_ptr->transformations & PNG_COMPOSE)
-      {
-         /* Issue a warning about this combination: because RGB_TO_GRAY is
-          * optimized to do the gamma transform if present yet do_background has
-          * to do the same thing if both options are set a
-          * double-gamma-correction happens.  This is true in all versions of
-          * libpng to date.
-          */
-         if (png_ptr->transformations & PNG_RGB_TO_GRAY)
-            png_warning(png_ptr,
-               "libpng does not support gamma+background+rgb_to_gray");
-
-         if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-         {
-            /* We don't get to here unless there is a tRNS chunk with non-opaque
-             * entries - see the checking code at the start of this function.
-             */
-            png_color back, back_1;
-            png_colorp palette = png_ptr->palette;
-            int num_palette = png_ptr->num_palette;
-            int i;
-            if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
-            {
-
-               back.red = png_ptr->gamma_table[png_ptr->background.red];
-               back.green = png_ptr->gamma_table[png_ptr->background.green];
-               back.blue = png_ptr->gamma_table[png_ptr->background.blue];
-
-               back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
-               back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
-               back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
-            }
-            else
-            {
-               png_fixed_point g, gs;
-
-               switch (png_ptr->background_gamma_type)
-               {
-                  case PNG_BACKGROUND_GAMMA_SCREEN:
-                     g = (png_ptr->screen_gamma);
-                     gs = PNG_FP_1;
-                     break;
-
-                  case PNG_BACKGROUND_GAMMA_FILE:
-                     g = png_reciprocal(png_ptr->gamma);
-                     gs = png_reciprocal2(png_ptr->gamma,
-                        png_ptr->screen_gamma);
-                     break;
-
-                  case PNG_BACKGROUND_GAMMA_UNIQUE:
-                     g = png_reciprocal(png_ptr->background_gamma);
-                     gs = png_reciprocal2(png_ptr->background_gamma,
-                        png_ptr->screen_gamma);
-                     break;
-                  default:
-                     g = PNG_FP_1;    /* back_1 */
-                     gs = PNG_FP_1;   /* back */
-                     break;
-               }
-
-               if (png_gamma_significant(gs))
-               {
-                  back.red = png_gamma_8bit_correct(png_ptr->background.red,
-                      gs);
-                  back.green = png_gamma_8bit_correct(png_ptr->background.green,
-                      gs);
-                  back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
-                      gs);
-               }
-
-               else
-               {
-                  back.red   = (png_byte)png_ptr->background.red;
-                  back.green = (png_byte)png_ptr->background.green;
-                  back.blue  = (png_byte)png_ptr->background.blue;
-               }
-
-               if (png_gamma_significant(g))
-               {
-                  back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
-                     g);
-                  back_1.green = png_gamma_8bit_correct(
-                     png_ptr->background.green, g);
-                  back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
-                     g);
-               }
-
-               else
-               {
-                  back_1.red   = (png_byte)png_ptr->background.red;
-                  back_1.green = (png_byte)png_ptr->background.green;
-                  back_1.blue  = (png_byte)png_ptr->background.blue;
-               }
-            }
-
-            for (i = 0; i < num_palette; i++)
-            {
-               if (i < (int)png_ptr->num_trans &&
-                   png_ptr->trans_alpha[i] != 0xff)
-               {
-                  if (png_ptr->trans_alpha[i] == 0)
-                  {
-                     palette[i] = back;
-                  }
-                  else /* if (png_ptr->trans_alpha[i] != 0xff) */
-                  {
-                     png_byte v, w;
-
-                     v = png_ptr->gamma_to_1[palette[i].red];
-                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.red);
-                     palette[i].red = png_ptr->gamma_from_1[w];
-
-                     v = png_ptr->gamma_to_1[palette[i].green];
-                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.green);
-                     palette[i].green = png_ptr->gamma_from_1[w];
-
-                     v = png_ptr->gamma_to_1[palette[i].blue];
-                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue);
-                     palette[i].blue = png_ptr->gamma_from_1[w];
-                  }
-               }
-               else
-               {
-                  palette[i].red = png_ptr->gamma_table[palette[i].red];
-                  palette[i].green = png_ptr->gamma_table[palette[i].green];
-                  palette[i].blue = png_ptr->gamma_table[palette[i].blue];
-               }
-            }
-
-            /* Prevent the transformations being done again.
-             *
-             * NOTE: this is highly dubious; it removes the transformations in
-             * place.  This seems inconsistent with the general treatment of the
-             * transformations elsewhere.
-             */
-            png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
-         } /* color_type == PNG_COLOR_TYPE_PALETTE */
-
-         /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
-         else /* color_type != PNG_COLOR_TYPE_PALETTE */
-         {
-            int gs_sig, g_sig;
-            png_fixed_point g = PNG_FP_1;  /* Correction to linear */
-            png_fixed_point gs = PNG_FP_1; /* Correction to screen */
-
-            switch (png_ptr->background_gamma_type)
-            {
-               case PNG_BACKGROUND_GAMMA_SCREEN:
-                  g = png_ptr->screen_gamma;
-                  /* gs = PNG_FP_1; */
-                  break;
-
-               case PNG_BACKGROUND_GAMMA_FILE:
-                  g = png_reciprocal(png_ptr->gamma);
-                  gs = png_reciprocal2(png_ptr->gamma, png_ptr->screen_gamma);
-                  break;
-
-               case PNG_BACKGROUND_GAMMA_UNIQUE:
-                  g = png_reciprocal(png_ptr->background_gamma);
-                  gs = png_reciprocal2(png_ptr->background_gamma,
-                      png_ptr->screen_gamma);
-                  break;
-
-               default:
-                  png_error(png_ptr, "invalid background gamma type");
-            }
-
-            g_sig = png_gamma_significant(g);
-            gs_sig = png_gamma_significant(gs);
-
-            if (g_sig)
-               png_ptr->background_1.gray = png_gamma_correct(png_ptr,
-                   png_ptr->background.gray, g);
-
-            if (gs_sig)
-               png_ptr->background.gray = png_gamma_correct(png_ptr,
-                   png_ptr->background.gray, gs);
-
-            if ((png_ptr->background.red != png_ptr->background.green) ||
-                (png_ptr->background.red != png_ptr->background.blue) ||
-                (png_ptr->background.red != png_ptr->background.gray))
-            {
-               /* RGB or RGBA with color background */
-               if (g_sig)
-               {
-                  png_ptr->background_1.red = png_gamma_correct(png_ptr,
-                      png_ptr->background.red, g);
-
-                  png_ptr->background_1.green = png_gamma_correct(png_ptr,
-                      png_ptr->background.green, g);
-
-                  png_ptr->background_1.blue = png_gamma_correct(png_ptr,
-                      png_ptr->background.blue, g);
-               }
-
-               if (gs_sig)
-               {
-                  png_ptr->background.red = png_gamma_correct(png_ptr,
-                      png_ptr->background.red, gs);
-
-                  png_ptr->background.green = png_gamma_correct(png_ptr,
-                      png_ptr->background.green, gs);
-
-                  png_ptr->background.blue = png_gamma_correct(png_ptr,
-                      png_ptr->background.blue, gs);
-               }
-            }
-
-            else
-            {
-               /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
-               png_ptr->background_1.red = png_ptr->background_1.green
-                   = png_ptr->background_1.blue = png_ptr->background_1.gray;
-
-               png_ptr->background.red = png_ptr->background.green
-                   = png_ptr->background.blue = png_ptr->background.gray;
-            }
-
-            /* The background is now in screen gamma: */
-            png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
-         } /* color_type != PNG_COLOR_TYPE_PALETTE */
-      }/* png_ptr->transformations & PNG_BACKGROUND */
-
-      else
-      /* Transformation does not include PNG_BACKGROUND */
-#endif /* PNG_READ_BACKGROUND_SUPPORTED */
-      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-         /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
-         && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
-         (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
-#endif
-         )
-      {
-         png_colorp palette = png_ptr->palette;
-         int num_palette = png_ptr->num_palette;
-         int i;
-
-         /*NOTE: there are other transformations that should probably be in here
-          * too.
-          */
-         for (i = 0; i < num_palette; i++)
-         {
-            palette[i].red = png_ptr->gamma_table[palette[i].red];
-            palette[i].green = png_ptr->gamma_table[palette[i].green];
-            palette[i].blue = png_ptr->gamma_table[palette[i].blue];
-         }
-
-         /* Done the gamma correction. */
-         png_ptr->transformations &= ~PNG_GAMMA;
-      } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
-   }
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-   else
-#endif
-#endif /* PNG_READ_GAMMA_SUPPORTED */
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-   /* No GAMMA transformation (see the hanging else 4 lines above) */
-   if ((png_ptr->transformations & PNG_COMPOSE) &&
-       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
-   {
-      int i;
-      int istop = (int)png_ptr->num_trans;
-      png_color back;
-      png_colorp palette = png_ptr->palette;
-
-      back.red   = (png_byte)png_ptr->background.red;
-      back.green = (png_byte)png_ptr->background.green;
-      back.blue  = (png_byte)png_ptr->background.blue;
-
-      for (i = 0; i < istop; i++)
-      {
-         if (png_ptr->trans_alpha[i] == 0)
-         {
-            palette[i] = back;
-         }
-
-         else if (png_ptr->trans_alpha[i] != 0xff)
-         {
-            /* The png_composite() macro is defined in png.h */
-            png_composite(palette[i].red, palette[i].red,
-                png_ptr->trans_alpha[i], back.red);
-
-            png_composite(palette[i].green, palette[i].green,
-                png_ptr->trans_alpha[i], back.green);
-
-            png_composite(palette[i].blue, palette[i].blue,
-                png_ptr->trans_alpha[i], back.blue);
-         }
-      }
-
-      png_ptr->transformations &= ~PNG_COMPOSE;
-   }
-#endif /* PNG_READ_BACKGROUND_SUPPORTED */
-
-#ifdef PNG_READ_SHIFT_SUPPORTED
-   if ((png_ptr->transformations & PNG_SHIFT) &&
-      !(png_ptr->transformations & PNG_EXPAND) &&
-       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
-   {
-      int i;
-      int istop = png_ptr->num_palette;
-      int shift = 8 - png_ptr->sig_bit.red;
-
-      png_ptr->transformations &= ~PNG_SHIFT;
-
-      /* significant bits can be in the range 1 to 7 for a meaninful result, if
-       * the number of significant bits is 0 then no shift is done (this is an
-       * error condition which is silently ignored.)
-       */
-      if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
-      {
-         int component = png_ptr->palette[i].red;
-
-         component >>= shift;
-         png_ptr->palette[i].red = (png_byte)component;
-      }
-
-      shift = 8 - png_ptr->sig_bit.green;
-      if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
-      {
-         int component = png_ptr->palette[i].green;
-
-         component >>= shift;
-         png_ptr->palette[i].green = (png_byte)component;
-      }
-
-      shift = 8 - png_ptr->sig_bit.blue;
-      if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
-      {
-         int component = png_ptr->palette[i].blue;
-
-         component >>= shift;
-         png_ptr->palette[i].blue = (png_byte)component;
-      }
-   }
-#endif  /* PNG_READ_SHIFT_SUPPORTED */
-}
-
-/* Modify the info structure to reflect the transformations.  The
- * info should be updated so a PNG file could be written with it,
- * assuming the transformations result in valid PNG data.
- */
-void /* PRIVATE */
-png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
-{
-   png_debug(1, "in png_read_transform_info");
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND)
-   {
-      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         /* This check must match what actually happens in
-          * png_do_expand_palette; if it ever checks the tRNS chunk to see if
-          * it is all opaque we must do the same (at present it does not.)
-          */
-         if (png_ptr->num_trans > 0)
-            info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-
-         else
-            info_ptr->color_type = PNG_COLOR_TYPE_RGB;
-
-         info_ptr->bit_depth = 8;
-         info_ptr->num_trans = 0;
-      }
-      else
-      {
-         if (png_ptr->num_trans)
-         {
-            if (png_ptr->transformations & PNG_EXPAND_tRNS)
-               info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
-         }
-         if (info_ptr->bit_depth < 8)
-            info_ptr->bit_depth = 8;
-
-         info_ptr->num_trans = 0;
-      }
-   }
-#endif
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   /* The following is almost certainly wrong unless the background value is in
-    * the screen space!
-    */
-   if (png_ptr->transformations & PNG_COMPOSE)
-      info_ptr->background = png_ptr->background;
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
-    * however it seems that the code in png_init_read_transformations, which has
-    * been called before this from png_read_update_info->png_read_start_row
-    * sometimes does the gamma transform and cancels the flag.
-    */
-   info_ptr->gamma = png_ptr->gamma;
-#endif
-
-   if (info_ptr->bit_depth == 16)
-   {
-#  ifdef PNG_READ_16BIT_SUPPORTED
-#     ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-         if (png_ptr->transformations & PNG_SCALE_16_TO_8)
-            info_ptr->bit_depth = 8;
-#     endif
-
-#     ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-         if (png_ptr->transformations & PNG_16_TO_8)
-            info_ptr->bit_depth = 8;
-#     endif
-
-#  else
-      /* No 16 bit support: force chopping 16-bit input down to 8, in this case
-       * the app program can chose if both APIs are available by setting the
-       * correct scaling to use.
-       */
-#     ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-         /* For compatibility with previous versions use the strip method by
-          * default.  This code works because if PNG_SCALE_16_TO_8 is already
-          * set the code below will do that in preference to the chop.
-          */
-         png_ptr->transformations |= PNG_16_TO_8;
-         info_ptr->bit_depth = 8;
-#     else
-
-#        ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-            png_ptr->transformations |= PNG_SCALE_16_TO_8;
-            info_ptr->bit_depth = 8;
-#        else
-
-            CONFIGURATION ERROR: you must enable at least one 16 to 8 method
-#        endif
-#    endif
-#endif /* !READ_16BIT_SUPPORTED */
-   }
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-   if (png_ptr->transformations & PNG_GRAY_TO_RGB)
-      info_ptr->color_type = (png_byte)(info_ptr->color_type |
-         PNG_COLOR_MASK_COLOR);
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
-      info_ptr->color_type = (png_byte)(info_ptr->color_type &
-         ~PNG_COLOR_MASK_COLOR);
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-   if (png_ptr->transformations & PNG_QUANTIZE)
-   {
-      if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
-          (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
-          png_ptr->palette_lookup && info_ptr->bit_depth == 8)
-      {
-         info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
-      }
-   }
-#endif
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 &&
-      info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
-   {
-      info_ptr->bit_depth = 16;
-   }
-#endif
-
-#ifdef PNG_READ_PACK_SUPPORTED
-   if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
-      info_ptr->bit_depth = 8;
-#endif
-
-   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      info_ptr->channels = 1;
-
-   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
-      info_ptr->channels = 3;
-
-   else
-      info_ptr->channels = 1;
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_STRIP_ALPHA)
-   {
-      info_ptr->color_type = (png_byte)(info_ptr->color_type &
-         ~PNG_COLOR_MASK_ALPHA);
-      info_ptr->num_trans = 0;
-   }
-#endif
-
-   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
-      info_ptr->channels++;
-
-#ifdef PNG_READ_FILLER_SUPPORTED
-   /* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */
-   if ((png_ptr->transformations & PNG_FILLER) &&
-       ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
-       (info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
-   {
-      info_ptr->channels++;
-      /* If adding a true alpha channel not just filler */
-      if (png_ptr->transformations & PNG_ADD_ALPHA)
-         info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
-   }
-#endif
-
-#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
-defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
-   {
-      if (info_ptr->bit_depth < png_ptr->user_transform_depth)
-         info_ptr->bit_depth = png_ptr->user_transform_depth;
-
-      if (info_ptr->channels < png_ptr->user_transform_channels)
-         info_ptr->channels = png_ptr->user_transform_channels;
-   }
-#endif
-
-   info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
-       info_ptr->bit_depth);
-
-   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
-
-   /* Adding in 1.5.4: cache the above value in png_struct so that we can later
-    * check in png_rowbytes that the user buffer won't get overwritten.  Note
-    * that the field is not always set - if png_read_update_info isn't called
-    * the application has to either not do any transforms or get the calculation
-    * right itself.
-    */
-   png_ptr->info_rowbytes = info_ptr->rowbytes;
-
-#ifndef PNG_READ_EXPAND_SUPPORTED
-   if (png_ptr)
-      return;
-#endif
-}
-
-/* Transform the row.  The order of transformations is significant,
- * and is very touchy.  If you add a transformation, take care to
- * decide how it fits in with the other transformations here.
- */
-void /* PRIVATE */
-png_do_read_transformations(png_structp png_ptr, png_row_infop row_info)
-{
-   png_debug(1, "in png_do_read_transformations");
-
-   if (png_ptr->row_buf == NULL)
-   {
-      /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
-       * error is incredibly rare and incredibly easy to debug without this
-       * information.
-       */
-      png_error(png_ptr, "NULL row buffer");
-   }
-
-   /* The following is debugging; prior to 1.5.4 the code was never compiled in;
-    * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
-    * PNG_WARN_UNINITIALIZED_ROW removed.  In 1.5 the new flag is set only for
-    * selected new APIs to ensure that there is no API change.
-    */
-   if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
-      !(png_ptr->flags & PNG_FLAG_ROW_INIT))
-   {
-      /* Application has failed to call either png_read_start_image() or
-       * png_read_update_info() after setting transforms that expand pixels.
-       * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
-       */
-      png_error(png_ptr, "Uninitialized row");
-   }
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND)
-   {
-      if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         png_do_expand_palette(row_info, png_ptr->row_buf + 1,
-             png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
-      }
-
-      else
-      {
-         if (png_ptr->num_trans &&
-             (png_ptr->transformations & PNG_EXPAND_tRNS))
-            png_do_expand(row_info, png_ptr->row_buf + 1,
-                &(png_ptr->trans_color));
-
-         else
-            png_do_expand(row_info, png_ptr->row_buf + 1,
-                NULL);
-      }
-   }
-#endif
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      !(png_ptr->transformations & PNG_COMPOSE) &&
-      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
-      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
-      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
-         0 /* at_start == false, because SWAP_ALPHA happens later */);
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
-   {
-      int rgb_error =
-          png_do_rgb_to_gray(png_ptr, row_info,
-              png_ptr->row_buf + 1);
-
-      if (rgb_error)
-      {
-         png_ptr->rgb_to_gray_status=1;
-         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
-             PNG_RGB_TO_GRAY_WARN)
-            png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
-
-         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
-             PNG_RGB_TO_GRAY_ERR)
-            png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
-      }
-   }
-#endif
-
-/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
- *
- *   In most cases, the "simple transparency" should be done prior to doing
- *   gray-to-RGB, or you will have to test 3x as many bytes to check if a
- *   pixel is transparent.  You would also need to make sure that the
- *   transparency information is upgraded to RGB.
- *
- *   To summarize, the current flow is:
- *   - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
- *                                   with background "in place" if transparent,
- *                                   convert to RGB if necessary
- *   - Gray + alpha -> composite with gray background and remove alpha bytes,
- *                                   convert to RGB if necessary
- *
- *   To support RGB backgrounds for gray images we need:
- *   - Gray + simple transparency -> convert to RGB + simple transparency,
- *                                   compare 3 or 6 bytes and composite with
- *                                   background "in place" if transparent
- *                                   (3x compare/pixel compared to doing
- *                                   composite with gray bkgrnd)
- *   - Gray + alpha -> convert to RGB + alpha, composite with background and
- *                                   remove alpha bytes (3x float
- *                                   operations/pixel compared with composite
- *                                   on gray background)
- *
- *  Greg's change will do this.  The reason it wasn't done before is for
- *  performance, as this increases the per-pixel operations.  If we would check
- *  in advance if the background was gray or RGB, and position the gray-to-RGB
- *  transform appropriately, then it would save a lot of work/time.
- */
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-   /* If gray -> RGB, do so now only if background is non-gray; else do later
-    * for performance reasons
-    */
-   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
-       !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
-      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
-#endif
-
-#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
-   (defined PNG_READ_ALPHA_MODE_SUPPORTED)
-   if (png_ptr->transformations & PNG_COMPOSE)
-      png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   if ((png_ptr->transformations & PNG_GAMMA) &&
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-      /* Because RGB_TO_GRAY does the gamma transform. */
-      !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
-#endif
-#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
-   (defined PNG_READ_ALPHA_MODE_SUPPORTED)
-      /* Because PNG_COMPOSE does the gamma transform if there is something to
-       * do (if there is an alpha channel or transparency.)
-       */
-       !((png_ptr->transformations & PNG_COMPOSE) &&
-       ((png_ptr->num_trans != 0) ||
-       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
-#endif
-      /* Because png_init_read_transformations transforms the palette, unless
-       * RGB_TO_GRAY will do the transform.
-       */
-       (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
-      png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
-#endif
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
-      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
-      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
-         0 /* at_start == false, because SWAP_ALPHA happens later */);
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-   if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
-      (row_info->color_type & PNG_COLOR_MASK_ALPHA))
-      png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
-#endif
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-   if (png_ptr->transformations & PNG_SCALE_16_TO_8)
-      png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-   /* There is no harm in doing both of these because only one has any effect,
-    * by putting the 'scale' option first if the app asks for scale (either by
-    * calling the API or in a TRANSFORM flag) this is what happens.
-    */
-   if (png_ptr->transformations & PNG_16_TO_8)
-      png_do_chop(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-   if (png_ptr->transformations & PNG_QUANTIZE)
-   {
-      png_do_quantize(row_info, png_ptr->row_buf + 1,
-          png_ptr->palette_lookup, png_ptr->quantize_index);
-
-      if (row_info->rowbytes == 0)
-         png_error(png_ptr, "png_do_quantize returned rowbytes=0");
-   }
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-   /* Do the expansion now, after all the arithmetic has been done.  Notice
-    * that previous transformations can handle the PNG_EXPAND_16 flag if this
-    * is efficient (particularly true in the case of gamma correction, where
-    * better accuracy results faster!)
-    */
-   if (png_ptr->transformations & PNG_EXPAND_16)
-      png_do_expand_16(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-   /*NOTE: moved here in 1.5.4 (from much later in this list.) */
-   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
-       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
-      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
-      png_do_invert(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
-      png_do_unshift(row_info, png_ptr->row_buf + 1,
-          &(png_ptr->shift));
-#endif
-
-#ifdef PNG_READ_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
-      png_do_unpack(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
-   /* Added at libpng-1.5.10 */
-   if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
-      png_do_check_palette_indexes(png_ptr, row_info);
-#endif
-
-#ifdef PNG_READ_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
-      png_do_bgr(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_PACKSWAP)
-      png_do_packswap(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_FILLER_SUPPORTED
-   if (png_ptr->transformations & PNG_FILLER)
-      png_do_read_filler(row_info, png_ptr->row_buf + 1,
-          (png_uint_32)png_ptr->filler, png_ptr->flags);
-#endif
-
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_ALPHA)
-      png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_ALPHA)
-      png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-#ifdef PNG_READ_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
-      png_do_swap(row_info, png_ptr->row_buf + 1);
-#endif
-#endif
-
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
-    {
-      if (png_ptr->read_user_transform_fn != NULL)
-         (*(png_ptr->read_user_transform_fn)) /* User read transform function */
-             (png_ptr,     /* png_ptr */
-             row_info,     /* row_info: */
-                /*  png_uint_32 width;       width of row */
-                /*  png_size_t rowbytes;     number of bytes in row */
-                /*  png_byte color_type;     color type of pixels */
-                /*  png_byte bit_depth;      bit depth of samples */
-                /*  png_byte channels;       number of channels (1-4) */
-                /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
-             png_ptr->row_buf + 1);    /* start of pixel data for row */
-#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-      if (png_ptr->user_transform_depth)
-         row_info->bit_depth = png_ptr->user_transform_depth;
-
-      if (png_ptr->user_transform_channels)
-         row_info->channels = png_ptr->user_transform_channels;
-#endif
-      row_info->pixel_depth = (png_byte)(row_info->bit_depth *
-          row_info->channels);
-
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
-   }
-#endif
-}
-
-#ifdef PNG_READ_PACK_SUPPORTED
-/* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
- * without changing the actual values.  Thus, if you had a row with
- * a bit depth of 1, you would end up with bytes that only contained
- * the numbers 0 or 1.  If you would rather they contain 0 and 255, use
- * png_do_shift() after this.
- */
-void /* PRIVATE */
-png_do_unpack(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_unpack");
-
-   if (row_info->bit_depth < 8)
-   {
-      png_uint_32 i;
-      png_uint_32 row_width=row_info->width;
-
-      switch (row_info->bit_depth)
-      {
-         case 1:
-         {
-            png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
-            png_bytep dp = row + (png_size_t)row_width - 1;
-            png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07);
-            for (i = 0; i < row_width; i++)
-            {
-               *dp = (png_byte)((*sp >> shift) & 0x01);
-
-               if (shift == 7)
-               {
-                  shift = 0;
-                  sp--;
-               }
-
-               else
-                  shift++;
-
-               dp--;
-            }
-            break;
-         }
-
-         case 2:
-         {
-
-            png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
-            png_bytep dp = row + (png_size_t)row_width - 1;
-            png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
-            for (i = 0; i < row_width; i++)
-            {
-               *dp = (png_byte)((*sp >> shift) & 0x03);
-
-               if (shift == 6)
-               {
-                  shift = 0;
-                  sp--;
-               }
-
-               else
-                  shift += 2;
-
-               dp--;
-            }
-            break;
-         }
-
-         case 4:
-         {
-            png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
-            png_bytep dp = row + (png_size_t)row_width - 1;
-            png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
-            for (i = 0; i < row_width; i++)
-            {
-               *dp = (png_byte)((*sp >> shift) & 0x0f);
-
-               if (shift == 4)
-               {
-                  shift = 0;
-                  sp--;
-               }
-
-               else
-                  shift = 4;
-
-               dp--;
-            }
-            break;
-         }
-
-         default:
-            break;
-      }
-      row_info->bit_depth = 8;
-      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
-      row_info->rowbytes = row_width * row_info->channels;
-   }
-}
-#endif
-
-#ifdef PNG_READ_SHIFT_SUPPORTED
-/* Reverse the effects of png_do_shift.  This routine merely shifts the
- * pixels back to their significant bits values.  Thus, if you have
- * a row of bit depth 8, but only 5 are significant, this will shift
- * the values back to 0 through 31.
- */
-void /* PRIVATE */
-png_do_unshift(png_row_infop row_info, png_bytep row,
-    png_const_color_8p sig_bits)
-{
-   int color_type;
-
-   png_debug(1, "in png_do_unshift");
-
-   /* The palette case has already been handled in the _init routine. */
-   color_type = row_info->color_type;
-
-   if (color_type != PNG_COLOR_TYPE_PALETTE)
-   {
-      int shift[4];
-      int channels = 0;
-      int bit_depth = row_info->bit_depth;
-
-      if (color_type & PNG_COLOR_MASK_COLOR)
-      {
-         shift[channels++] = bit_depth - sig_bits->red;
-         shift[channels++] = bit_depth - sig_bits->green;
-         shift[channels++] = bit_depth - sig_bits->blue;
-      }
-
-      else
-      {
-         shift[channels++] = bit_depth - sig_bits->gray;
-      }
-
-      if (color_type & PNG_COLOR_MASK_ALPHA)
-      {
-         shift[channels++] = bit_depth - sig_bits->alpha;
-      }
-
-      {
-         int c, have_shift;
-
-         for (c = have_shift = 0; c < channels; ++c)
-         {
-            /* A shift of more than the bit depth is an error condition but it
-             * gets ignored here.
-             */
-            if (shift[c] <= 0 || shift[c] >= bit_depth)
-               shift[c] = 0;
-
-            else
-               have_shift = 1;
-         }
-
-         if (!have_shift)
-            return;
-      }
-
-      switch (bit_depth)
-      {
-         default:
-         /* Must be 1bpp gray: should not be here! */
-            /* NOTREACHED */
-            break;
-
-         case 2:
-         /* Must be 2bpp gray */
-         /* assert(channels == 1 && shift[0] == 1) */
-         {
-            png_bytep bp = row;
-            png_bytep bp_end = bp + row_info->rowbytes;
-
-            while (bp < bp_end)
-            {
-               int b = (*bp >> 1) & 0x55;
-               *bp++ = (png_byte)b;
-            }
-            break;
-         }
-
-         case 4:
-         /* Must be 4bpp gray */
-         /* assert(channels == 1) */
-         {
-            png_bytep bp = row;
-            png_bytep bp_end = bp + row_info->rowbytes;
-            int gray_shift = shift[0];
-            int mask =  0xf >> gray_shift;
-
-            mask |= mask << 4;
-
-            while (bp < bp_end)
-            {
-               int b = (*bp >> gray_shift) & mask;
-               *bp++ = (png_byte)b;
-            }
-            break;
-         }
-
-         case 8:
-         /* Single byte components, G, GA, RGB, RGBA */
-         {
-            png_bytep bp = row;
-            png_bytep bp_end = bp + row_info->rowbytes;
-            int channel = 0;
-
-            while (bp < bp_end)
-            {
-               int b = *bp >> shift[channel];
-               if (++channel >= channels)
-                  channel = 0;
-               *bp++ = (png_byte)b;
-            }
-            break;
-         }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-         case 16:
-         /* Double byte components, G, GA, RGB, RGBA */
-         {
-            png_bytep bp = row;
-            png_bytep bp_end = bp + row_info->rowbytes;
-            int channel = 0;
-
-            while (bp < bp_end)
-            {
-               int value = (bp[0] << 8) + bp[1];
-
-               value >>= shift[channel];
-               if (++channel >= channels)
-                  channel = 0;
-               *bp++ = (png_byte)(value >> 8);
-               *bp++ = (png_byte)(value & 0xff);
-            }
-            break;
-         }
-#endif
-      }
-   }
-}
-#endif
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-/* Scale rows of bit depth 16 down to 8 accurately */
-void /* PRIVATE */
-png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_scale_16_to_8");
-
-   if (row_info->bit_depth == 16)
-   {
-      png_bytep sp = row; /* source */
-      png_bytep dp = row; /* destination */
-      png_bytep ep = sp + row_info->rowbytes; /* end+1 */
-
-      while (sp < ep)
-      {
-         /* The input is an array of 16 bit components, these must be scaled to
-          * 8 bits each.  For a 16 bit value V the required value (from the PNG
-          * specification) is:
-          *
-          *    (V * 255) / 65535
-          *
-          * This reduces to round(V / 257), or floor((V + 128.5)/257)
-          *
-          * Represent V as the two byte value vhi.vlo.  Make a guess that the
-          * result is the top byte of V, vhi, then the correction to this value
-          * is:
-          *
-          *    error = floor(((V-vhi.vhi) + 128.5) / 257)
-          *          = floor(((vlo-vhi) + 128.5) / 257)
-          *
-          * This can be approximated using integer arithmetic (and a signed
-          * shift):
-          *
-          *    error = (vlo-vhi+128) >> 8;
-          *
-          * The approximate differs from the exact answer only when (vlo-vhi) is
-          * 128; it then gives a correction of +1 when the exact correction is
-          * 0.  This gives 128 errors.  The exact answer (correct for all 16 bit
-          * input values) is:
-          *
-          *    error = (vlo-vhi+128)*65535 >> 24;
-          *
-          * An alternative arithmetic calculation which also gives no errors is:
-          *
-          *    (V * 255 + 32895) >> 16
-          */
-
-         png_int_32 tmp = *sp++; /* must be signed! */
-         tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
-         *dp++ = (png_byte)tmp;
-      }
-
-      row_info->bit_depth = 8;
-      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
-      row_info->rowbytes = row_info->width * row_info->channels;
-   }
-}
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-void /* PRIVATE */
-/* Simply discard the low byte.  This was the default behavior prior
- * to libpng-1.5.4.
- */
-png_do_chop(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_chop");
-
-   if (row_info->bit_depth == 16)
-   {
-      png_bytep sp = row; /* source */
-      png_bytep dp = row; /* destination */
-      png_bytep ep = sp + row_info->rowbytes; /* end+1 */
-
-      while (sp < ep)
-      {
-         *dp++ = *sp;
-         sp += 2; /* skip low byte */
-      }
-
-      row_info->bit_depth = 8;
-      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
-      row_info->rowbytes = row_info->width * row_info->channels;
-   }
-}
-#endif
-
-#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
-void /* PRIVATE */
-png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_read_swap_alpha");
-
-   {
-      png_uint_32 row_width = row_info->width;
-      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-      {
-         /* This converts from RGBA to ARGB */
-         if (row_info->bit_depth == 8)
-         {
-            png_bytep sp = row + row_info->rowbytes;
-            png_bytep dp = sp;
-            png_byte save;
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               save = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = save;
-            }
-         }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-         /* This converts from RRGGBBAA to AARRGGBB */
-         else
-         {
-            png_bytep sp = row + row_info->rowbytes;
-            png_bytep dp = sp;
-            png_byte save[2];
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               save[0] = *(--sp);
-               save[1] = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = save[0];
-               *(--dp) = save[1];
-            }
-         }
-#endif
-      }
-
-      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      {
-         /* This converts from GA to AG */
-         if (row_info->bit_depth == 8)
-         {
-            png_bytep sp = row + row_info->rowbytes;
-            png_bytep dp = sp;
-            png_byte save;
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               save = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = save;
-            }
-         }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-         /* This converts from GGAA to AAGG */
-         else
-         {
-            png_bytep sp = row + row_info->rowbytes;
-            png_bytep dp = sp;
-            png_byte save[2];
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               save[0] = *(--sp);
-               save[1] = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = save[0];
-               *(--dp) = save[1];
-            }
-         }
-#endif
-      }
-   }
-}
-#endif
-
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-void /* PRIVATE */
-png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
-{
-   png_uint_32 row_width;
-   png_debug(1, "in png_do_read_invert_alpha");
-
-   row_width = row_info->width;
-   if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-   {
-      if (row_info->bit_depth == 8)
-      {
-         /* This inverts the alpha channel in RGBA */
-         png_bytep sp = row + row_info->rowbytes;
-         png_bytep dp = sp;
-         png_uint_32 i;
-
-         for (i = 0; i < row_width; i++)
-         {
-            *(--dp) = (png_byte)(255 - *(--sp));
-
-/*          This does nothing:
-            *(--dp) = *(--sp);
-            *(--dp) = *(--sp);
-            *(--dp) = *(--sp);
-            We can replace it with:
-*/
-            sp-=3;
-            dp=sp;
-         }
-      }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-      /* This inverts the alpha channel in RRGGBBAA */
-      else
-      {
-         png_bytep sp = row + row_info->rowbytes;
-         png_bytep dp = sp;
-         png_uint_32 i;
-
-         for (i = 0; i < row_width; i++)
-         {
-            *(--dp) = (png_byte)(255 - *(--sp));
-            *(--dp) = (png_byte)(255 - *(--sp));
-
-/*          This does nothing:
-            *(--dp) = *(--sp);
-            *(--dp) = *(--sp);
-            *(--dp) = *(--sp);
-            *(--dp) = *(--sp);
-            *(--dp) = *(--sp);
-            *(--dp) = *(--sp);
-            We can replace it with:
-*/
-            sp-=6;
-            dp=sp;
-         }
-      }
-#endif
-   }
-   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-   {
-      if (row_info->bit_depth == 8)
-      {
-         /* This inverts the alpha channel in GA */
-         png_bytep sp = row + row_info->rowbytes;
-         png_bytep dp = sp;
-         png_uint_32 i;
-
-         for (i = 0; i < row_width; i++)
-         {
-            *(--dp) = (png_byte)(255 - *(--sp));
-            *(--dp) = *(--sp);
-         }
-      }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-      else
-      {
-         /* This inverts the alpha channel in GGAA */
-         png_bytep sp  = row + row_info->rowbytes;
-         png_bytep dp = sp;
-         png_uint_32 i;
-
-         for (i = 0; i < row_width; i++)
-         {
-            *(--dp) = (png_byte)(255 - *(--sp));
-            *(--dp) = (png_byte)(255 - *(--sp));
-/*
-            *(--dp) = *(--sp);
-            *(--dp) = *(--sp);
-*/
-            sp-=2;
-            dp=sp;
-         }
-      }
-#endif
-   }
-}
-#endif
-
-#ifdef PNG_READ_FILLER_SUPPORTED
-/* Add filler channel if we have RGB color */
-void /* PRIVATE */
-png_do_read_filler(png_row_infop row_info, png_bytep row,
-    png_uint_32 filler, png_uint_32 flags)
-{
-   png_uint_32 i;
-   png_uint_32 row_width = row_info->width;
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-   png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
-#endif
-   png_byte lo_filler = (png_byte)(filler & 0xff);
-
-   png_debug(1, "in png_do_read_filler");
-
-   if (
-       row_info->color_type == PNG_COLOR_TYPE_GRAY)
-   {
-      if (row_info->bit_depth == 8)
-      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
-         {
-            /* This changes the data from G to GX */
-            png_bytep sp = row + (png_size_t)row_width;
-            png_bytep dp =  sp + (png_size_t)row_width;
-            for (i = 1; i < row_width; i++)
-            {
-               *(--dp) = lo_filler;
-               *(--dp) = *(--sp);
-            }
-            *(--dp) = lo_filler;
-            row_info->channels = 2;
-            row_info->pixel_depth = 16;
-            row_info->rowbytes = row_width * 2;
-         }
-
-         else
-         {
-            /* This changes the data from G to XG */
-            png_bytep sp = row + (png_size_t)row_width;
-            png_bytep dp = sp  + (png_size_t)row_width;
-            for (i = 0; i < row_width; i++)
-            {
-               *(--dp) = *(--sp);
-               *(--dp) = lo_filler;
-            }
-            row_info->channels = 2;
-            row_info->pixel_depth = 16;
-            row_info->rowbytes = row_width * 2;
-         }
-      }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-      else if (row_info->bit_depth == 16)
-      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
-         {
-            /* This changes the data from GG to GGXX */
-            png_bytep sp = row + (png_size_t)row_width * 2;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
-            for (i = 1; i < row_width; i++)
-            {
-               *(--dp) = hi_filler;
-               *(--dp) = lo_filler;
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-            }
-            *(--dp) = hi_filler;
-            *(--dp) = lo_filler;
-            row_info->channels = 2;
-            row_info->pixel_depth = 32;
-            row_info->rowbytes = row_width * 4;
-         }
-
-         else
-         {
-            /* This changes the data from GG to XXGG */
-            png_bytep sp = row + (png_size_t)row_width * 2;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
-            for (i = 0; i < row_width; i++)
-            {
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = hi_filler;
-               *(--dp) = lo_filler;
-            }
-            row_info->channels = 2;
-            row_info->pixel_depth = 32;
-            row_info->rowbytes = row_width * 4;
-         }
-      }
-#endif
-   } /* COLOR_TYPE == GRAY */
-   else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-   {
-      if (row_info->bit_depth == 8)
-      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
-         {
-            /* This changes the data from RGB to RGBX */
-            png_bytep sp = row + (png_size_t)row_width * 3;
-            png_bytep dp = sp  + (png_size_t)row_width;
-            for (i = 1; i < row_width; i++)
-            {
-               *(--dp) = lo_filler;
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-            }
-            *(--dp) = lo_filler;
-            row_info->channels = 4;
-            row_info->pixel_depth = 32;
-            row_info->rowbytes = row_width * 4;
-         }
-
-         else
-         {
-            /* This changes the data from RGB to XRGB */
-            png_bytep sp = row + (png_size_t)row_width * 3;
-            png_bytep dp = sp + (png_size_t)row_width;
-            for (i = 0; i < row_width; i++)
-            {
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = lo_filler;
-            }
-            row_info->channels = 4;
-            row_info->pixel_depth = 32;
-            row_info->rowbytes = row_width * 4;
-         }
-      }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-      else if (row_info->bit_depth == 16)
-      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
-         {
-            /* This changes the data from RRGGBB to RRGGBBXX */
-            png_bytep sp = row + (png_size_t)row_width * 6;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
-            for (i = 1; i < row_width; i++)
-            {
-               *(--dp) = hi_filler;
-               *(--dp) = lo_filler;
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-            }
-            *(--dp) = hi_filler;
-            *(--dp) = lo_filler;
-            row_info->channels = 4;
-            row_info->pixel_depth = 64;
-            row_info->rowbytes = row_width * 8;
-         }
-
-         else
-         {
-            /* This changes the data from RRGGBB to XXRRGGBB */
-            png_bytep sp = row + (png_size_t)row_width * 6;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
-            for (i = 0; i < row_width; i++)
-            {
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = hi_filler;
-               *(--dp) = lo_filler;
-            }
-
-            row_info->channels = 4;
-            row_info->pixel_depth = 64;
-            row_info->rowbytes = row_width * 8;
-         }
-      }
-#endif
-   } /* COLOR_TYPE == RGB */
-}
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-/* Expand grayscale files to RGB, with or without alpha */
-void /* PRIVATE */
-png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
-{
-   png_uint_32 i;
-   png_uint_32 row_width = row_info->width;
-
-   png_debug(1, "in png_do_gray_to_rgb");
-
-   if (row_info->bit_depth >= 8 &&
-       !(row_info->color_type & PNG_COLOR_MASK_COLOR))
-   {
-      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This changes G to RGB */
-            png_bytep sp = row + (png_size_t)row_width - 1;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
-            for (i = 0; i < row_width; i++)
-            {
-               *(dp--) = *sp;
-               *(dp--) = *sp;
-               *(dp--) = *(sp--);
-            }
-         }
-
-         else
-         {
-            /* This changes GG to RRGGBB */
-            png_bytep sp = row + (png_size_t)row_width * 2 - 1;
-            png_bytep dp = sp  + (png_size_t)row_width * 4;
-            for (i = 0; i < row_width; i++)
-            {
-               *(dp--) = *sp;
-               *(dp--) = *(sp - 1);
-               *(dp--) = *sp;
-               *(dp--) = *(sp - 1);
-               *(dp--) = *(sp--);
-               *(dp--) = *(sp--);
-            }
-         }
-      }
-
-      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This changes GA to RGBA */
-            png_bytep sp = row + (png_size_t)row_width * 2 - 1;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
-            for (i = 0; i < row_width; i++)
-            {
-               *(dp--) = *(sp--);
-               *(dp--) = *sp;
-               *(dp--) = *sp;
-               *(dp--) = *(sp--);
-            }
-         }
-
-         else
-         {
-            /* This changes GGAA to RRGGBBAA */
-            png_bytep sp = row + (png_size_t)row_width * 4 - 1;
-            png_bytep dp = sp  + (png_size_t)row_width * 4;
-            for (i = 0; i < row_width; i++)
-            {
-               *(dp--) = *(sp--);
-               *(dp--) = *(sp--);
-               *(dp--) = *sp;
-               *(dp--) = *(sp - 1);
-               *(dp--) = *sp;
-               *(dp--) = *(sp - 1);
-               *(dp--) = *(sp--);
-               *(dp--) = *(sp--);
-            }
-         }
-      }
-      row_info->channels = (png_byte)(row_info->channels + 2);
-      row_info->color_type |= PNG_COLOR_MASK_COLOR;
-      row_info->pixel_depth = (png_byte)(row_info->channels *
-          row_info->bit_depth);
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
-   }
-}
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-/* Reduce RGB files to grayscale, with or without alpha
- * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
- * <http://www.inforamp.net/~poynton/>  (THIS LINK IS DEAD June 2008 but
- * versions dated 1998 through November 2002 have been archived at
- * http://web.archive.org/web/20000816232553/http://www.inforamp.net/
- * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
- * Charles Poynton poynton at poynton.com
- *
- *     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
- *
- *  which can be expressed with integers as
- *
- *     Y = (6969 * R + 23434 * G + 2365 * B)/32768
- *
- * Poynton's current link (as of January 2003 through July 2011):
- * <http://www.poynton.com/notes/colour_and_gamma/>
- * has changed the numbers slightly:
- *
- *     Y = 0.2126*R + 0.7152*G + 0.0722*B
- *
- *  which can be expressed with integers as
- *
- *     Y = (6966 * R + 23436 * G + 2366 * B)/32768
- *
- *  Historically, however, libpng uses numbers derived from the ITU-R Rec 709
- *  end point chromaticities and the D65 white point.  Depending on the
- *  precision used for the D65 white point this produces a variety of different
- *  numbers, however if the four decimal place value used in ITU-R Rec 709 is
- *  used (0.3127,0.3290) the Y calculation would be:
- *
- *     Y = (6968 * R + 23435 * G + 2366 * B)/32768
- *
- *  While this is correct the rounding results in an overflow for white, because
- *  the sum of the rounded coefficients is 32769, not 32768.  Consequently
- *  libpng uses, instead, the closest non-overflowing approximation:
- *
- *     Y = (6968 * R + 23434 * G + 2366 * B)/32768
- *
- *  Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
- *  (including an sRGB chunk) then the chromaticities are used to calculate the
- *  coefficients.  See the chunk handling in pngrutil.c for more information.
- *
- *  In all cases the calculation is to be done in a linear colorspace.  If no
- *  gamma information is available to correct the encoding of the original RGB
- *  values this results in an implicit assumption that the original PNG RGB
- *  values were linear.
- *
- *  Other integer coefficents can be used via png_set_rgb_to_gray().  Because
- *  the API takes just red and green coefficients the blue coefficient is
- *  calculated to make the sum 32768.  This will result in different rounding
- *  to that used above.
- */
-int /* PRIVATE */
-png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
-
-{
-   int rgb_error = 0;
-
-   png_debug(1, "in png_do_rgb_to_gray");
-
-   if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) &&
-       (row_info->color_type & PNG_COLOR_MASK_COLOR))
-   {
-      PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
-      PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
-      PNG_CONST png_uint_32 bc = 32768 - rc - gc;
-      PNG_CONST png_uint_32 row_width = row_info->width;
-      PNG_CONST int have_alpha =
-         (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
-
-      if (row_info->bit_depth == 8)
-      {
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
-         /* Notice that gamma to/from 1 are not necessarily inverses (if
-          * there is an overall gamma correction).  Prior to 1.5.5 this code
-          * checked the linearized values for equality; this doesn't match
-          * the documentation, the original values must be checked.
-          */
-         if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
-         {
-            png_bytep sp = row;
-            png_bytep dp = row;
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               png_byte red   = *(sp++);
-               png_byte green = *(sp++);
-               png_byte blue  = *(sp++);
-
-               if (red != green || red != blue)
-               {
-                  red = png_ptr->gamma_to_1[red];
-                  green = png_ptr->gamma_to_1[green];
-                  blue = png_ptr->gamma_to_1[blue];
-
-                  rgb_error |= 1;
-                  *(dp++) = png_ptr->gamma_from_1[
-                      (rc*red + gc*green + bc*blue + 16384)>>15];
-               }
-
-               else
-               {
-                  /* If there is no overall correction the table will not be
-                   * set.
-                   */
-                  if (png_ptr->gamma_table != NULL)
-                     red = png_ptr->gamma_table[red];
-
-                  *(dp++) = red;
-               }
-
-               if (have_alpha)
-                  *(dp++) = *(sp++);
-            }
-         }
-         else
-#endif
-         {
-            png_bytep sp = row;
-            png_bytep dp = row;
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               png_byte red   = *(sp++);
-               png_byte green = *(sp++);
-               png_byte blue  = *(sp++);
-
-               if (red != green || red != blue)
-               {
-                  rgb_error |= 1;
-                  /*NOTE: this is the historical approach which simply
-                   * truncates the results.
-                   */
-                  *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
-               }
-
-               else
-                  *(dp++) = red;
-
-               if (have_alpha)
-                  *(dp++) = *(sp++);
-            }
-         }
-      }
-
-      else /* RGB bit_depth == 16 */
-      {
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
-         if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
-         {
-            png_bytep sp = row;
-            png_bytep dp = row;
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               png_uint_16 red, green, blue, w;
-
-               red   = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               blue  = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-
-               if (red == green && red == blue)
-               {
-                  if (png_ptr->gamma_16_table != NULL)
-                     w = png_ptr->gamma_16_table[(red&0xff)
-                         >> png_ptr->gamma_shift][red>>8];
-
-                  else
-                     w = red;
-               }
-
-               else
-               {
-                  png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff)
-                      >> png_ptr->gamma_shift][red>>8];
-                  png_uint_16 green_1 =
-                      png_ptr->gamma_16_to_1[(green&0xff) >>
-                      png_ptr->gamma_shift][green>>8];
-                  png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff)
-                      >> png_ptr->gamma_shift][blue>>8];
-                  png_uint_16 gray16  = (png_uint_16)((rc*red_1 + gc*green_1
-                      + bc*blue_1 + 16384)>>15);
-                  w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
-                      png_ptr->gamma_shift][gray16 >> 8];
-                  rgb_error |= 1;
-               }
-
-               *(dp++) = (png_byte)((w>>8) & 0xff);
-               *(dp++) = (png_byte)(w & 0xff);
-
-               if (have_alpha)
-               {
-                  *(dp++) = *(sp++);
-                  *(dp++) = *(sp++);
-               }
-            }
-         }
-         else
-#endif
-         {
-            png_bytep sp = row;
-            png_bytep dp = row;
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               png_uint_16 red, green, blue, gray16;
-
-               red   = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               blue  = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-
-               if (red != green || red != blue)
-                  rgb_error |= 1;
-
-               /* From 1.5.5 in the 16 bit case do the accurate conversion even
-                * in the 'fast' case - this is because this is where the code
-                * ends up when handling linear 16 bit data.
-                */
-               gray16  = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
-                  15);
-               *(dp++) = (png_byte)((gray16>>8) & 0xff);
-               *(dp++) = (png_byte)(gray16 & 0xff);
-
-               if (have_alpha)
-               {
-                  *(dp++) = *(sp++);
-                  *(dp++) = *(sp++);
-               }
-            }
-         }
-      }
-
-      row_info->channels = (png_byte)(row_info->channels - 2);
-      row_info->color_type = (png_byte)(row_info->color_type &
-          ~PNG_COLOR_MASK_COLOR);
-      row_info->pixel_depth = (png_byte)(row_info->channels *
-          row_info->bit_depth);
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
-   }
-   return rgb_error;
-}
-#endif
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
-/* Build a grayscale palette.  Palette is assumed to be 1 << bit_depth
- * large of png_color.  This lets grayscale images be treated as
- * paletted.  Most useful for gamma correction and simplification
- * of code.  This API is not used internally.
- */
-void PNGAPI
-png_build_grayscale_palette(int bit_depth, png_colorp palette)
-{
-   int num_palette;
-   int color_inc;
-   int i;
-   int v;
-
-   png_debug(1, "in png_do_build_grayscale_palette");
-
-   if (palette == NULL)
-      return;
-
-   switch (bit_depth)
-   {
-      case 1:
-         num_palette = 2;
-         color_inc = 0xff;
-         break;
-
-      case 2:
-         num_palette = 4;
-         color_inc = 0x55;
-         break;
-
-      case 4:
-         num_palette = 16;
-         color_inc = 0x11;
-         break;
-
-      case 8:
-         num_palette = 256;
-         color_inc = 1;
-         break;
-
-      default:
-         num_palette = 0;
-         color_inc = 0;
-         break;
-   }
-
-   for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
-   {
-      palette[i].red = (png_byte)v;
-      palette[i].green = (png_byte)v;
-      palette[i].blue = (png_byte)v;
-   }
-}
-#endif
-
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
-   (defined PNG_READ_ALPHA_MODE_SUPPORTED)
-/* Replace any alpha or transparency with the supplied background color.
- * "background" is already in the screen gamma, while "background_1" is
- * at a gamma of 1.0.  Paletted files have already been taken care of.
- */
-void /* PRIVATE */
-png_do_compose(png_row_infop row_info, png_bytep row, png_structp png_ptr)
-{
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   png_const_bytep gamma_table = png_ptr->gamma_table;
-   png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
-   png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
-   png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
-   png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
-   png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
-   int gamma_shift = png_ptr->gamma_shift;
-#endif
-
-   png_bytep sp;
-   png_uint_32 i;
-   png_uint_32 row_width = row_info->width;
-   int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
-   int shift;
-
-   png_debug(1, "in png_do_compose");
-
-   {
-      switch (row_info->color_type)
-      {
-         case PNG_COLOR_TYPE_GRAY:
-         {
-            switch (row_info->bit_depth)
-            {
-               case 1:
-               {
-                  sp = row;
-                  shift = 7;
-                  for (i = 0; i < row_width; i++)
-                  {
-                     if ((png_uint_16)((*sp >> shift) & 0x01)
-                        == png_ptr->trans_color.gray)
-                     {
-                        *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
-                        *sp |= (png_byte)(png_ptr->background.gray << shift);
-                     }
-
-                     if (!shift)
-                     {
-                        shift = 7;
-                        sp++;
-                     }
-
-                     else
-                        shift--;
-                  }
-                  break;
-               }
-
-               case 2:
-               {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-                  if (gamma_table != NULL)
-                  {
-                     sp = row;
-                     shift = 6;
-                     for (i = 0; i < row_width; i++)
-                     {
-                        if ((png_uint_16)((*sp >> shift) & 0x03)
-                            == png_ptr->trans_color.gray)
-                        {
-                           *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
-                           *sp |= (png_byte)(png_ptr->background.gray << shift);
-                        }
-
-                        else
-                        {
-                           png_byte p = (png_byte)((*sp >> shift) & 0x03);
-                           png_byte g = (png_byte)((gamma_table [p | (p << 2) |
-                               (p << 4) | (p << 6)] >> 6) & 0x03);
-                           *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
-                           *sp |= (png_byte)(g << shift);
-                        }
-
-                        if (!shift)
-                        {
-                           shift = 6;
-                           sp++;
-                        }
-
-                        else
-                           shift -= 2;
-                     }
-                  }
-
-                  else
-#endif
-                  {
-                     sp = row;
-                     shift = 6;
-                     for (i = 0; i < row_width; i++)
-                     {
-                        if ((png_uint_16)((*sp >> shift) & 0x03)
-                            == png_ptr->trans_color.gray)
-                        {
-                           *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
-                           *sp |= (png_byte)(png_ptr->background.gray << shift);
-                        }
-
-                        if (!shift)
-                        {
-                           shift = 6;
-                           sp++;
-                        }
-
-                        else
-                           shift -= 2;
-                     }
-                  }
-                  break;
-               }
-
-               case 4:
-               {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-                  if (gamma_table != NULL)
-                  {
-                     sp = row;
-                     shift = 4;
-                     for (i = 0; i < row_width; i++)
-                     {
-                        if ((png_uint_16)((*sp >> shift) & 0x0f)
-                            == png_ptr->trans_color.gray)
-                        {
-                           *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
-                           *sp |= (png_byte)(png_ptr->background.gray << shift);
-                        }
-
-                        else
-                        {
-                           png_byte p = (png_byte)((*sp >> shift) & 0x0f);
-                           png_byte g = (png_byte)((gamma_table[p |
-                               (p << 4)] >> 4) & 0x0f);
-                           *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
-                           *sp |= (png_byte)(g << shift);
-                        }
-
-                        if (!shift)
-                        {
-                           shift = 4;
-                           sp++;
-                        }
-
-                        else
-                           shift -= 4;
-                     }
-                  }
-
-                  else
-#endif
-                  {
-                     sp = row;
-                     shift = 4;
-                     for (i = 0; i < row_width; i++)
-                     {
-                        if ((png_uint_16)((*sp >> shift) & 0x0f)
-                            == png_ptr->trans_color.gray)
-                        {
-                           *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
-                           *sp |= (png_byte)(png_ptr->background.gray << shift);
-                        }
-
-                        if (!shift)
-                        {
-                           shift = 4;
-                           sp++;
-                        }
-
-                        else
-                           shift -= 4;
-                     }
-                  }
-                  break;
-               }
-
-               case 8:
-               {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-                  if (gamma_table != NULL)
-                  {
-                     sp = row;
-                     for (i = 0; i < row_width; i++, sp++)
-                     {
-                        if (*sp == png_ptr->trans_color.gray)
-                           *sp = (png_byte)png_ptr->background.gray;
-
-                        else
-                           *sp = gamma_table[*sp];
-                     }
-                  }
-                  else
-#endif
-                  {
-                     sp = row;
-                     for (i = 0; i < row_width; i++, sp++)
-                     {
-                        if (*sp == png_ptr->trans_color.gray)
-                           *sp = (png_byte)png_ptr->background.gray;
-                     }
-                  }
-                  break;
-               }
-
-               case 16:
-               {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-                  if (gamma_16 != NULL)
-                  {
-                     sp = row;
-                     for (i = 0; i < row_width; i++, sp += 2)
-                     {
-                        png_uint_16 v;
-
-                        v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
-                        if (v == png_ptr->trans_color.gray)
-                        {
-                           /* Background is already in screen gamma */
-                           *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
-                           *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
-                        }
-
-                        else
-                        {
-                           v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
-                           *sp = (png_byte)((v >> 8) & 0xff);
-                           *(sp + 1) = (png_byte)(v & 0xff);
-                        }
-                     }
-                  }
-                  else
-#endif
-                  {
-                     sp = row;
-                     for (i = 0; i < row_width; i++, sp += 2)
-                     {
-                        png_uint_16 v;
-
-                        v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
-                        if (v == png_ptr->trans_color.gray)
-                        {
-                           *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
-                           *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
-                        }
-                     }
-                  }
-                  break;
-               }
-
-               default:
-                  break;
-            }
-            break;
-         }
-
-         case PNG_COLOR_TYPE_RGB:
-         {
-            if (row_info->bit_depth == 8)
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_table != NULL)
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 3)
-                  {
-                     if (*sp == png_ptr->trans_color.red &&
-                         *(sp + 1) == png_ptr->trans_color.green &&
-                         *(sp + 2) == png_ptr->trans_color.blue)
-                     {
-                        *sp = (png_byte)png_ptr->background.red;
-                        *(sp + 1) = (png_byte)png_ptr->background.green;
-                        *(sp + 2) = (png_byte)png_ptr->background.blue;
-                     }
-
-                     else
-                     {
-                        *sp = gamma_table[*sp];
-                        *(sp + 1) = gamma_table[*(sp + 1)];
-                        *(sp + 2) = gamma_table[*(sp + 2)];
-                     }
-                  }
-               }
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 3)
-                  {
-                     if (*sp == png_ptr->trans_color.red &&
-                         *(sp + 1) == png_ptr->trans_color.green &&
-                         *(sp + 2) == png_ptr->trans_color.blue)
-                     {
-                        *sp = (png_byte)png_ptr->background.red;
-                        *(sp + 1) = (png_byte)png_ptr->background.green;
-                        *(sp + 2) = (png_byte)png_ptr->background.blue;
-                     }
-                  }
-               }
-            }
-            else /* if (row_info->bit_depth == 16) */
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_16 != NULL)
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 6)
-                  {
-                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
-                     png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
-                         + *(sp + 3));
-
-                     png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
-                         + *(sp + 5));
-
-                     if (r == png_ptr->trans_color.red &&
-                         g == png_ptr->trans_color.green &&
-                         b == png_ptr->trans_color.blue)
-                     {
-                        /* Background is already in screen gamma */
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
-                     }
-
-                     else
-                     {
-                        png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
-
-                        v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
-                        *(sp + 2) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(v & 0xff);
-
-                        v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
-                        *(sp + 4) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(v & 0xff);
-                     }
-                  }
-               }
-
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 6)
-                  {
-                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
-                     png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
-                         + *(sp + 3));
-
-                     png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
-                         + *(sp + 5));
-
-                     if (r == png_ptr->trans_color.red &&
-                         g == png_ptr->trans_color.green &&
-                         b == png_ptr->trans_color.blue)
-                     {
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
-                     }
-                  }
-               }
-            }
-            break;
-         }
-
-         case PNG_COLOR_TYPE_GRAY_ALPHA:
-         {
-            if (row_info->bit_depth == 8)
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
-                   gamma_table != NULL)
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 2)
-                  {
-                     png_uint_16 a = *(sp + 1);
-
-                     if (a == 0xff)
-                        *sp = gamma_table[*sp];
-
-                     else if (a == 0)
-                     {
-                        /* Background is already in screen gamma */
-                        *sp = (png_byte)png_ptr->background.gray;
-                     }
-
-                     else
-                     {
-                        png_byte v, w;
-
-                        v = gamma_to_1[*sp];
-                        png_composite(w, v, a, png_ptr->background_1.gray);
-                        if (!optimize)
-                           w = gamma_from_1[w];
-                        *sp = w;
-                     }
-                  }
-               }
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 2)
-                  {
-                     png_byte a = *(sp + 1);
-
-                     if (a == 0)
-                        *sp = (png_byte)png_ptr->background.gray;
-
-                     else if (a < 0xff)
-                        png_composite(*sp, *sp, a, png_ptr->background_1.gray);
-                  }
-               }
-            }
-            else /* if (png_ptr->bit_depth == 16) */
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
-                   gamma_16_to_1 != NULL)
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 4)
-                  {
-                     png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
-                         + *(sp + 3));
-
-                     if (a == (png_uint_16)0xffff)
-                     {
-                        png_uint_16 v;
-
-                        v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
-                     }
-
-                     else if (a == 0)
-                     {
-                        /* Background is already in screen gamma */
-                        *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
-                     }
-
-                     else
-                     {
-                        png_uint_16 g, v, w;
-
-                        g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
-                        png_composite_16(v, g, a, png_ptr->background_1.gray);
-                        if (optimize)
-                           w = v;
-                        else
-                           w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
-                        *sp = (png_byte)((w >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(w & 0xff);
-                     }
-                  }
-               }
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 4)
-                  {
-                     png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
-                         + *(sp + 3));
-
-                     if (a == 0)
-                     {
-                        *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
-                     }
-
-                     else if (a < 0xffff)
-                     {
-                        png_uint_16 g, v;
-
-                        g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-                        png_composite_16(v, g, a, png_ptr->background_1.gray);
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
-                     }
-                  }
-               }
-            }
-            break;
-         }
-
-         case PNG_COLOR_TYPE_RGB_ALPHA:
-         {
-            if (row_info->bit_depth == 8)
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
-                   gamma_table != NULL)
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 4)
-                  {
-                     png_byte a = *(sp + 3);
-
-                     if (a == 0xff)
-                     {
-                        *sp = gamma_table[*sp];
-                        *(sp + 1) = gamma_table[*(sp + 1)];
-                        *(sp + 2) = gamma_table[*(sp + 2)];
-                     }
-
-                     else if (a == 0)
-                     {
-                        /* Background is already in screen gamma */
-                        *sp = (png_byte)png_ptr->background.red;
-                        *(sp + 1) = (png_byte)png_ptr->background.green;
-                        *(sp + 2) = (png_byte)png_ptr->background.blue;
-                     }
-
-                     else
-                     {
-                        png_byte v, w;
-
-                        v = gamma_to_1[*sp];
-                        png_composite(w, v, a, png_ptr->background_1.red);
-                        if (!optimize) w = gamma_from_1[w];
-                        *sp = w;
-
-                        v = gamma_to_1[*(sp + 1)];
-                        png_composite(w, v, a, png_ptr->background_1.green);
-                        if (!optimize) w = gamma_from_1[w];
-                        *(sp + 1) = w;
-
-                        v = gamma_to_1[*(sp + 2)];
-                        png_composite(w, v, a, png_ptr->background_1.blue);
-                        if (!optimize) w = gamma_from_1[w];
-                        *(sp + 2) = w;
-                     }
-                  }
-               }
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 4)
-                  {
-                     png_byte a = *(sp + 3);
-
-                     if (a == 0)
-                     {
-                        *sp = (png_byte)png_ptr->background.red;
-                        *(sp + 1) = (png_byte)png_ptr->background.green;
-                        *(sp + 2) = (png_byte)png_ptr->background.blue;
-                     }
-
-                     else if (a < 0xff)
-                     {
-                        png_composite(*sp, *sp, a, png_ptr->background.red);
-
-                        png_composite(*(sp + 1), *(sp + 1), a,
-                            png_ptr->background.green);
-
-                        png_composite(*(sp + 2), *(sp + 2), a,
-                            png_ptr->background.blue);
-                     }
-                  }
-               }
-            }
-            else /* if (row_info->bit_depth == 16) */
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
-                   gamma_16_to_1 != NULL)
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 8)
-                  {
-                     png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
-                         << 8) + (png_uint_16)(*(sp + 7)));
-
-                     if (a == (png_uint_16)0xffff)
-                     {
-                        png_uint_16 v;
-
-                        v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
-
-                        v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
-                        *(sp + 2) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(v & 0xff);
-
-                        v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
-                        *(sp + 4) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(v & 0xff);
-                     }
-
-                     else if (a == 0)
-                     {
-                        /* Background is already in screen gamma */
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
-                     }
-
-                     else
-                     {
-                        png_uint_16 v, w;
-
-                        v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
-                        png_composite_16(w, v, a, png_ptr->background_1.red);
-                        if (!optimize)
-                           w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
-                        *sp = (png_byte)((w >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(w & 0xff);
-
-                        v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
-                        png_composite_16(w, v, a, png_ptr->background_1.green);
-                        if (!optimize)
-                           w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
-
-                        *(sp + 2) = (png_byte)((w >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(w & 0xff);
-
-                        v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
-                        png_composite_16(w, v, a, png_ptr->background_1.blue);
-                        if (!optimize)
-                           w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
-
-                        *(sp + 4) = (png_byte)((w >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(w & 0xff);
-                     }
-                  }
-               }
-
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 8)
-                  {
-                     png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
-                         << 8) + (png_uint_16)(*(sp + 7)));
-
-                     if (a == 0)
-                     {
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
-                     }
-
-                     else if (a < 0xffff)
-                     {
-                        png_uint_16 v;
-
-                        png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-                        png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
-                            + *(sp + 3));
-                        png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
-                            + *(sp + 5));
-
-                        png_composite_16(v, r, a, png_ptr->background.red);
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
-
-                        png_composite_16(v, g, a, png_ptr->background.green);
-                        *(sp + 2) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(v & 0xff);
-
-                        png_composite_16(v, b, a, png_ptr->background.blue);
-                        *(sp + 4) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(v & 0xff);
-                     }
-                  }
-               }
-            }
-            break;
-         }
-
-         default:
-            break;
-      }
-   }
-}
-#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_READ_ALPHA_MODE_SUPPORTED */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-/* Gamma correct the image, avoiding the alpha channel.  Make sure
- * you do this after you deal with the transparency issue on grayscale
- * or RGB images. If your bit depth is 8, use gamma_table, if it
- * is 16, use gamma_16_table and gamma_shift.  Build these with
- * build_gamma_table().
- */
-void /* PRIVATE */
-png_do_gamma(png_row_infop row_info, png_bytep row, png_structp png_ptr)
-{
-   png_const_bytep gamma_table = png_ptr->gamma_table;
-   png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
-   int gamma_shift = png_ptr->gamma_shift;
-
-   png_bytep sp;
-   png_uint_32 i;
-   png_uint_32 row_width=row_info->width;
-
-   png_debug(1, "in png_do_gamma");
-
-   if (((row_info->bit_depth <= 8 && gamma_table != NULL) ||
-       (row_info->bit_depth == 16 && gamma_16_table != NULL)))
-   {
-      switch (row_info->color_type)
-      {
-         case PNG_COLOR_TYPE_RGB:
-         {
-            if (row_info->bit_depth == 8)
-            {
-               sp = row;
-               for (i = 0; i < row_width; i++)
-               {
-                  *sp = gamma_table[*sp];
-                  sp++;
-                  *sp = gamma_table[*sp];
-                  sp++;
-                  *sp = gamma_table[*sp];
-                  sp++;
-               }
-            }
-
-            else /* if (row_info->bit_depth == 16) */
-            {
-               sp = row;
-               for (i = 0; i < row_width; i++)
-               {
-                  png_uint_16 v;
-
-                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
-                  *sp = (png_byte)((v >> 8) & 0xff);
-                  *(sp + 1) = (png_byte)(v & 0xff);
-                  sp += 2;
-
-                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
-                  *sp = (png_byte)((v >> 8) & 0xff);
-                  *(sp + 1) = (png_byte)(v & 0xff);
-                  sp += 2;
-
-                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
-                  *sp = (png_byte)((v >> 8) & 0xff);
-                  *(sp + 1) = (png_byte)(v & 0xff);
-                  sp += 2;
-               }
-            }
-            break;
-         }
-
-         case PNG_COLOR_TYPE_RGB_ALPHA:
-         {
-            if (row_info->bit_depth == 8)
-            {
-               sp = row;
-               for (i = 0; i < row_width; i++)
-               {
-                  *sp = gamma_table[*sp];
-                  sp++;
-
-                  *sp = gamma_table[*sp];
-                  sp++;
-
-                  *sp = gamma_table[*sp];
-                  sp++;
-
-                  sp++;
-               }
-            }
-
-            else /* if (row_info->bit_depth == 16) */
-            {
-               sp = row;
-               for (i = 0; i < row_width; i++)
-               {
-                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
-                  *sp = (png_byte)((v >> 8) & 0xff);
-                  *(sp + 1) = (png_byte)(v & 0xff);
-                  sp += 2;
-
-                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
-                  *sp = (png_byte)((v >> 8) & 0xff);
-                  *(sp + 1) = (png_byte)(v & 0xff);
-                  sp += 2;
-
-                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
-                  *sp = (png_byte)((v >> 8) & 0xff);
-                  *(sp + 1) = (png_byte)(v & 0xff);
-                  sp += 4;
-               }
-            }
-            break;
-         }
-
-         case PNG_COLOR_TYPE_GRAY_ALPHA:
-         {
-            if (row_info->bit_depth == 8)
-            {
-               sp = row;
-               for (i = 0; i < row_width; i++)
-               {
-                  *sp = gamma_table[*sp];
-                  sp += 2;
-               }
-            }
-
-            else /* if (row_info->bit_depth == 16) */
-            {
-               sp = row;
-               for (i = 0; i < row_width; i++)
-               {
-                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
-                  *sp = (png_byte)((v >> 8) & 0xff);
-                  *(sp + 1) = (png_byte)(v & 0xff);
-                  sp += 4;
-               }
-            }
-            break;
-         }
-
-         case PNG_COLOR_TYPE_GRAY:
-         {
-            if (row_info->bit_depth == 2)
-            {
-               sp = row;
-               for (i = 0; i < row_width; i += 4)
-               {
-                  int a = *sp & 0xc0;
-                  int b = *sp & 0x30;
-                  int c = *sp & 0x0c;
-                  int d = *sp & 0x03;
-
-                  *sp = (png_byte)(
-                      ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])   ) & 0xc0)|
-                      ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
-                      ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
-                      ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
-                  sp++;
-               }
-            }
-
-            if (row_info->bit_depth == 4)
-            {
-               sp = row;
-               for (i = 0; i < row_width; i += 2)
-               {
-                  int msb = *sp & 0xf0;
-                  int lsb = *sp & 0x0f;
-
-                  *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
-                      | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
-                  sp++;
-               }
-            }
-
-            else if (row_info->bit_depth == 8)
-            {
-               sp = row;
-               for (i = 0; i < row_width; i++)
-               {
-                  *sp = gamma_table[*sp];
-                  sp++;
-               }
-            }
-
-            else if (row_info->bit_depth == 16)
-            {
-               sp = row;
-               for (i = 0; i < row_width; i++)
-               {
-                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
-                  *sp = (png_byte)((v >> 8) & 0xff);
-                  *(sp + 1) = (png_byte)(v & 0xff);
-                  sp += 2;
-               }
-            }
-            break;
-         }
-
-         default:
-            break;
-      }
-   }
-}
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-/* Encode the alpha channel to the output gamma (the input channel is always
- * linear.)  Called only with color types that have an alpha channel.  Needs the
- * from_1 tables.
- */
-void /* PRIVATE */
-png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structp png_ptr)
-{
-   png_uint_32 row_width = row_info->width;
-
-   png_debug(1, "in png_do_encode_alpha");
-
-   if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
-   {
-      if (row_info->bit_depth == 8)
-      {
-         PNG_CONST png_bytep table = png_ptr->gamma_from_1;
-
-         if (table != NULL)
-         {
-            PNG_CONST int step =
-               (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
-
-            /* The alpha channel is the last component: */
-            row += step - 1;
-
-            for (; row_width > 0; --row_width, row += step)
-               *row = table[*row];
-
-            return;
-         }
-      }
-
-      else if (row_info->bit_depth == 16)
-      {
-         PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1;
-         PNG_CONST int gamma_shift = png_ptr->gamma_shift;
-
-         if (table != NULL)
-         {
-            PNG_CONST int step =
-               (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
-
-            /* The alpha channel is the last component: */
-            row += step - 2;
-
-            for (; row_width > 0; --row_width, row += step)
-            {
-               png_uint_16 v;
-
-               v = table[*(row + 1) >> gamma_shift][*row];
-               *row = (png_byte)((v >> 8) & 0xff);
-               *(row + 1) = (png_byte)(v & 0xff);
-            }
-
-            return;
-         }
-      }
-   }
-
-   /* Only get to here if called with a weird row_info; no harm has been done,
-    * so just issue a warning.
-    */
-   png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
-}
-#endif
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* Expands a palette row to an RGB or RGBA row depending
- * upon whether you supply trans and num_trans.
- */
-void /* PRIVATE */
-png_do_expand_palette(png_row_infop row_info, png_bytep row,
-   png_const_colorp palette, png_const_bytep trans_alpha, int num_trans)
-{
-   int shift, value;
-   png_bytep sp, dp;
-   png_uint_32 i;
-   png_uint_32 row_width=row_info->width;
-
-   png_debug(1, "in png_do_expand_palette");
-
-   if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      if (row_info->bit_depth < 8)
-      {
-         switch (row_info->bit_depth)
-         {
-            case 1:
-            {
-               sp = row + (png_size_t)((row_width - 1) >> 3);
-               dp = row + (png_size_t)row_width - 1;
-               shift = 7 - (int)((row_width + 7) & 0x07);
-               for (i = 0; i < row_width; i++)
-               {
-                  if ((*sp >> shift) & 0x01)
-                     *dp = 1;
-
-                  else
-                     *dp = 0;
-
-                  if (shift == 7)
-                  {
-                     shift = 0;
-                     sp--;
-                  }
-
-                  else
-                     shift++;
-
-                  dp--;
-               }
-               break;
-            }
-
-            case 2:
-            {
-               sp = row + (png_size_t)((row_width - 1) >> 2);
-               dp = row + (png_size_t)row_width - 1;
-               shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
-               for (i = 0; i < row_width; i++)
-               {
-                  value = (*sp >> shift) & 0x03;
-                  *dp = (png_byte)value;
-                  if (shift == 6)
-                  {
-                     shift = 0;
-                     sp--;
-                  }
-
-                  else
-                     shift += 2;
-
-                  dp--;
-               }
-               break;
-            }
-
-            case 4:
-            {
-               sp = row + (png_size_t)((row_width - 1) >> 1);
-               dp = row + (png_size_t)row_width - 1;
-               shift = (int)((row_width & 0x01) << 2);
-               for (i = 0; i < row_width; i++)
-               {
-                  value = (*sp >> shift) & 0x0f;
-                  *dp = (png_byte)value;
-                  if (shift == 4)
-                  {
-                     shift = 0;
-                     sp--;
-                  }
-
-                  else
-                     shift += 4;
-
-                  dp--;
-               }
-               break;
-            }
-
-            default:
-               break;
-         }
-         row_info->bit_depth = 8;
-         row_info->pixel_depth = 8;
-         row_info->rowbytes = row_width;
-      }
-
-      if (row_info->bit_depth == 8)
-      {
-         {
-            if (num_trans > 0)
-            {
-               sp = row + (png_size_t)row_width - 1;
-               dp = row + (png_size_t)(row_width << 2) - 1;
-
-               for (i = 0; i < row_width; i++)
-               {
-                  if ((int)(*sp) >= num_trans)
-                     *dp-- = 0xff;
-
-                  else
-                     *dp-- = trans_alpha[*sp];
-
-                  *dp-- = palette[*sp].blue;
-                  *dp-- = palette[*sp].green;
-                  *dp-- = palette[*sp].red;
-                  sp--;
-               }
-               row_info->bit_depth = 8;
-               row_info->pixel_depth = 32;
-               row_info->rowbytes = row_width * 4;
-               row_info->color_type = 6;
-               row_info->channels = 4;
-            }
-
-            else
-            {
-               sp = row + (png_size_t)row_width - 1;
-               dp = row + (png_size_t)(row_width * 3) - 1;
-
-               for (i = 0; i < row_width; i++)
-               {
-                  *dp-- = palette[*sp].blue;
-                  *dp-- = palette[*sp].green;
-                  *dp-- = palette[*sp].red;
-                  sp--;
-               }
-
-               row_info->bit_depth = 8;
-               row_info->pixel_depth = 24;
-               row_info->rowbytes = row_width * 3;
-               row_info->color_type = 2;
-               row_info->channels = 3;
-            }
-         }
-      }
-   }
-}
-
-/* If the bit depth < 8, it is expanded to 8.  Also, if the already
- * expanded transparency value is supplied, an alpha channel is built.
- */
-void /* PRIVATE */
-png_do_expand(png_row_infop row_info, png_bytep row,
-    png_const_color_16p trans_color)
-{
-   int shift, value;
-   png_bytep sp, dp;
-   png_uint_32 i;
-   png_uint_32 row_width=row_info->width;
-
-   png_debug(1, "in png_do_expand");
-
-   {
-      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
-      {
-         png_uint_16 gray = (png_uint_16)(trans_color ? trans_color->gray : 0);
-
-         if (row_info->bit_depth < 8)
-         {
-            switch (row_info->bit_depth)
-            {
-               case 1:
-               {
-                  gray = (png_uint_16)((gray & 0x01) * 0xff);
-                  sp = row + (png_size_t)((row_width - 1) >> 3);
-                  dp = row + (png_size_t)row_width - 1;
-                  shift = 7 - (int)((row_width + 7) & 0x07);
-                  for (i = 0; i < row_width; i++)
-                  {
-                     if ((*sp >> shift) & 0x01)
-                        *dp = 0xff;
-
-                     else
-                        *dp = 0;
-
-                     if (shift == 7)
-                     {
-                        shift = 0;
-                        sp--;
-                     }
-
-                     else
-                        shift++;
-
-                     dp--;
-                  }
-                  break;
-               }
-
-               case 2:
-               {
-                  gray = (png_uint_16)((gray & 0x03) * 0x55);
-                  sp = row + (png_size_t)((row_width - 1) >> 2);
-                  dp = row + (png_size_t)row_width - 1;
-                  shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
-                  for (i = 0; i < row_width; i++)
-                  {
-                     value = (*sp >> shift) & 0x03;
-                     *dp = (png_byte)(value | (value << 2) | (value << 4) |
-                        (value << 6));
-                     if (shift == 6)
-                     {
-                        shift = 0;
-                        sp--;
-                     }
-
-                     else
-                        shift += 2;
-
-                     dp--;
-                  }
-                  break;
-               }
-
-               case 4:
-               {
-                  gray = (png_uint_16)((gray & 0x0f) * 0x11);
-                  sp = row + (png_size_t)((row_width - 1) >> 1);
-                  dp = row + (png_size_t)row_width - 1;
-                  shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
-                  for (i = 0; i < row_width; i++)
-                  {
-                     value = (*sp >> shift) & 0x0f;
-                     *dp = (png_byte)(value | (value << 4));
-                     if (shift == 4)
-                     {
-                        shift = 0;
-                        sp--;
-                     }
-
-                     else
-                        shift = 4;
-
-                     dp--;
-                  }
-                  break;
-               }
-
-               default:
-                  break;
-            }
-
-            row_info->bit_depth = 8;
-            row_info->pixel_depth = 8;
-            row_info->rowbytes = row_width;
-         }
-
-         if (trans_color != NULL)
-         {
-            if (row_info->bit_depth == 8)
-            {
-               gray = gray & 0xff;
-               sp = row + (png_size_t)row_width - 1;
-               dp = row + (png_size_t)(row_width << 1) - 1;
-
-               for (i = 0; i < row_width; i++)
-               {
-                  if (*sp == gray)
-                     *dp-- = 0;
-
-                  else
-                     *dp-- = 0xff;
-
-                  *dp-- = *sp--;
-               }
-            }
-
-            else if (row_info->bit_depth == 16)
-            {
-               png_byte gray_high = (png_byte)((gray >> 8) & 0xff);
-               png_byte gray_low = (png_byte)(gray & 0xff);
-               sp = row + row_info->rowbytes - 1;
-               dp = row + (row_info->rowbytes << 1) - 1;
-               for (i = 0; i < row_width; i++)
-               {
-                  if (*(sp - 1) == gray_high && *(sp) == gray_low)
-                  {
-                     *dp-- = 0;
-                     *dp-- = 0;
-                  }
-
-                  else
-                  {
-                     *dp-- = 0xff;
-                     *dp-- = 0xff;
-                  }
-
-                  *dp-- = *sp--;
-                  *dp-- = *sp--;
-               }
-            }
-
-            row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
-            row_info->channels = 2;
-            row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
-            row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
-               row_width);
-         }
-      }
-      else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            png_byte red = (png_byte)(trans_color->red & 0xff);
-            png_byte green = (png_byte)(trans_color->green & 0xff);
-            png_byte blue = (png_byte)(trans_color->blue & 0xff);
-            sp = row + (png_size_t)row_info->rowbytes - 1;
-            dp = row + (png_size_t)(row_width << 2) - 1;
-            for (i = 0; i < row_width; i++)
-            {
-               if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
-                  *dp-- = 0;
-
-               else
-                  *dp-- = 0xff;
-
-               *dp-- = *sp--;
-               *dp-- = *sp--;
-               *dp-- = *sp--;
-            }
-         }
-         else if (row_info->bit_depth == 16)
-         {
-            png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
-            png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
-            png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
-            png_byte red_low = (png_byte)(trans_color->red & 0xff);
-            png_byte green_low = (png_byte)(trans_color->green & 0xff);
-            png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
-            sp = row + row_info->rowbytes - 1;
-            dp = row + (png_size_t)(row_width << 3) - 1;
-            for (i = 0; i < row_width; i++)
-            {
-               if (*(sp - 5) == red_high &&
-                   *(sp - 4) == red_low &&
-                   *(sp - 3) == green_high &&
-                   *(sp - 2) == green_low &&
-                   *(sp - 1) == blue_high &&
-                   *(sp    ) == blue_low)
-               {
-                  *dp-- = 0;
-                  *dp-- = 0;
-               }
-
-               else
-               {
-                  *dp-- = 0xff;
-                  *dp-- = 0xff;
-               }
-
-               *dp-- = *sp--;
-               *dp-- = *sp--;
-               *dp-- = *sp--;
-               *dp-- = *sp--;
-               *dp-- = *sp--;
-               *dp-- = *sp--;
-            }
-         }
-         row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-         row_info->channels = 4;
-         row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
-         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
-      }
-   }
-}
-#endif
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* If the bit depth is 8 and the color type is not a palette type expand the
- * whole row to 16 bits.  Has no effect otherwise.
- */
-void /* PRIVATE */
-png_do_expand_16(png_row_infop row_info, png_bytep row)
-{
-   if (row_info->bit_depth == 8 &&
-      row_info->color_type != PNG_COLOR_TYPE_PALETTE)
-   {
-      /* The row have a sequence of bytes containing [0..255] and we need
-       * to turn it into another row containing [0..65535], to do this we
-       * calculate:
-       *
-       *  (input / 255) * 65535
-       *
-       *  Which happens to be exactly input * 257 and this can be achieved
-       *  simply by byte replication in place (copying backwards).
-       */
-      png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
-      png_byte *dp = sp + row_info->rowbytes;  /* destination, end + 1 */
-      while (dp > sp)
-         dp[-2] = dp[-1] = *--sp, dp -= 2;
-
-      row_info->rowbytes *= 2;
-      row_info->bit_depth = 16;
-      row_info->pixel_depth = (png_byte)(row_info->channels * 16);
-   }
-}
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-void /* PRIVATE */
-png_do_quantize(png_row_infop row_info, png_bytep row,
-    png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
-{
-   png_bytep sp, dp;
-   png_uint_32 i;
-   png_uint_32 row_width=row_info->width;
-
-   png_debug(1, "in png_do_quantize");
-
-   if (row_info->bit_depth == 8)
-   {
-      if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup)
-      {
-         int r, g, b, p;
-         sp = row;
-         dp = row;
-         for (i = 0; i < row_width; i++)
-         {
-            r = *sp++;
-            g = *sp++;
-            b = *sp++;
-
-            /* This looks real messy, but the compiler will reduce
-             * it down to a reasonable formula.  For example, with
-             * 5 bits per color, we get:
-             * p = (((r >> 3) & 0x1f) << 10) |
-             *    (((g >> 3) & 0x1f) << 5) |
-             *    ((b >> 3) & 0x1f);
-             */
-            p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
-                ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
-                (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
-                (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
-                ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
-                (PNG_QUANTIZE_BLUE_BITS)) |
-                ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
-                ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
-
-            *dp++ = palette_lookup[p];
-         }
-
-         row_info->color_type = PNG_COLOR_TYPE_PALETTE;
-         row_info->channels = 1;
-         row_info->pixel_depth = row_info->bit_depth;
-         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
-      }
-
-      else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
-         palette_lookup != NULL)
-      {
-         int r, g, b, p;
-         sp = row;
-         dp = row;
-         for (i = 0; i < row_width; i++)
-         {
-            r = *sp++;
-            g = *sp++;
-            b = *sp++;
-            sp++;
-
-            p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
-                ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
-                (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
-                (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
-                ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
-                (PNG_QUANTIZE_BLUE_BITS)) |
-                ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
-                ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
-
-            *dp++ = palette_lookup[p];
-         }
-
-         row_info->color_type = PNG_COLOR_TYPE_PALETTE;
-         row_info->channels = 1;
-         row_info->pixel_depth = row_info->bit_depth;
-         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
-      }
-
-      else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
-         quantize_lookup)
-      {
-         sp = row;
-
-         for (i = 0; i < row_width; i++, sp++)
-         {
-            *sp = quantize_lookup[*sp];
-         }
-      }
-   }
-}
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-/* Undoes intrapixel differencing  */
-void /* PRIVATE */
-png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_read_intrapixel");
-
-   if (
-       (row_info->color_type & PNG_COLOR_MASK_COLOR))
-   {
-      int bytes_per_pixel;
-      png_uint_32 row_width = row_info->width;
-
-      if (row_info->bit_depth == 8)
-      {
-         png_bytep rp;
-         png_uint_32 i;
-
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 3;
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 4;
-
-         else
-            return;
-
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
-            *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
-         }
-      }
-      else if (row_info->bit_depth == 16)
-      {
-         png_bytep rp;
-         png_uint_32 i;
-
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 6;
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 8;
-
-         else
-            return;
-
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
-            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
-            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
-            png_uint_32 red  = (s0 + s1 + 65536) & 0xffff;
-            png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
-            *(rp    ) = (png_byte)((red >> 8) & 0xff);
-            *(rp + 1) = (png_byte)(red & 0xff);
-            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
-            *(rp + 5) = (png_byte)(blue & 0xff);
-         }
-      }
-   }
-}
-#endif /* PNG_MNG_FEATURES_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED */
diff --git a/extern/libpng/include/pngrutil.c b/extern/libpng/include/pngrutil.c
deleted file mode 100644
index aa592ccfbd..0000000000
--- a/extern/libpng/include/pngrutil.c
+++ /dev/null
@@ -1,4159 +0,0 @@
-
-/* pngrutil.c - utilities to read a PNG file
- *
- * Last changed in libpng 1.5.10 [March 8, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * This file contains routines that are only called from within
- * libpng itself during the course of reading an image.
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_READ_SUPPORTED
-
-#define png_strtod(p,a,b) strtod(a,b)
-
-png_uint_32 PNGAPI
-png_get_uint_31(png_structp png_ptr, png_const_bytep buf)
-{
-   png_uint_32 uval = png_get_uint_32(buf);
-
-   if (uval > PNG_UINT_31_MAX)
-      png_error(png_ptr, "PNG unsigned integer out of range");
-
-   return (uval);
-}
-
-#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
-/* The following is a variation on the above for use with the fixed
- * point values used for gAMA and cHRM.  Instead of png_error it
- * issues a warning and returns (-1) - an invalid value because both
- * gAMA and cHRM use *unsigned* integers for fixed point values.
- */
-#define PNG_FIXED_ERROR (-1)
-
-static png_fixed_point /* PRIVATE */
-png_get_fixed_point(png_structp png_ptr, png_const_bytep buf)
-{
-   png_uint_32 uval = png_get_uint_32(buf);
-
-   if (uval <= PNG_UINT_31_MAX)
-      return (png_fixed_point)uval; /* known to be in range */
-
-   /* The caller can turn off the warning by passing NULL. */
-   if (png_ptr != NULL)
-      png_warning(png_ptr, "PNG fixed point integer out of range");
-
-   return PNG_FIXED_ERROR;
-}
-#endif
-
-#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
-/* NOTE: the read macros will obscure these definitions, so that if
- * PNG_USE_READ_MACROS is set the library will not use them internally,
- * but the APIs will still be available externally.
- *
- * The parentheses around "PNGAPI function_name" in the following three
- * functions are necessary because they allow the macros to co-exist with
- * these (unused but exported) functions.
- */
-
-/* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
-png_uint_32 (PNGAPI
-png_get_uint_32)(png_const_bytep buf)
-{
-   png_uint_32 uval =
-       ((png_uint_32)(*(buf    )) << 24) +
-       ((png_uint_32)(*(buf + 1)) << 16) +
-       ((png_uint_32)(*(buf + 2)) <<  8) +
-       ((png_uint_32)(*(buf + 3))      ) ;
-
-   return uval;
-}
-
-/* Grab a signed 32-bit integer from a buffer in big-endian format.  The
- * data is stored in the PNG file in two's complement format and there
- * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
- * the following code does a two's complement to native conversion.
- */
-png_int_32 (PNGAPI
-png_get_int_32)(png_const_bytep buf)
-{
-   png_uint_32 uval = png_get_uint_32(buf);
-   if ((uval & 0x80000000) == 0) /* non-negative */
-      return uval;
-
-   uval = (uval ^ 0xffffffff) + 1;  /* 2's complement: -x = ~x+1 */
-   return -(png_int_32)uval;
-}
-
-/* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
-png_uint_16 (PNGAPI
-png_get_uint_16)(png_const_bytep buf)
-{
-   /* ANSI-C requires an int value to accomodate at least 16 bits so this
-    * works and allows the compiler not to worry about possible narrowing
-    * on 32 bit systems.  (Pre-ANSI systems did not make integers smaller
-    * than 16 bits either.)
-    */
-   unsigned int val =
-       ((unsigned int)(*buf) << 8) +
-       ((unsigned int)(*(buf + 1)));
-
-   return (png_uint_16)val;
-}
-
-#endif /* PNG_READ_INT_FUNCTIONS_SUPPORTED */
-
-/* Read and check the PNG file signature */
-void /* PRIVATE */
-png_read_sig(png_structp png_ptr, png_infop info_ptr)
-{
-   png_size_t num_checked, num_to_check;
-
-   /* Exit if the user application does not expect a signature. */
-   if (png_ptr->sig_bytes >= 8)
-      return;
-
-   num_checked = png_ptr->sig_bytes;
-   num_to_check = 8 - num_checked;
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
-#endif
-
-   /* The signature must be serialized in a single I/O call. */
-   png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
-   png_ptr->sig_bytes = 8;
-
-   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
-   {
-      if (num_checked < 4 &&
-          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
-         png_error(png_ptr, "Not a PNG file");
-      else
-         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
-   }
-   if (num_checked < 3)
-      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
-}
-
-/* Read the chunk header (length + type name).
- * Put the type name into png_ptr->chunk_name, and return the length.
- */
-png_uint_32 /* PRIVATE */
-png_read_chunk_header(png_structp png_ptr)
-{
-   png_byte buf[8];
-   png_uint_32 length;
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
-#endif
-
-   /* Read the length and the chunk name.
-    * This must be performed in a single I/O call.
-    */
-   png_read_data(png_ptr, buf, 8);
-   length = png_get_uint_31(png_ptr, buf);
-
-   /* Put the chunk name into png_ptr->chunk_name. */
-   png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
-
-   png_debug2(0, "Reading %lx chunk, length = %lu",
-       (unsigned long)png_ptr->chunk_name, (unsigned long)length);
-
-   /* Reset the crc and run it over the chunk name. */
-   png_reset_crc(png_ptr);
-   png_calculate_crc(png_ptr, buf + 4, 4);
-
-   /* Check to see if chunk name is valid. */
-   png_check_chunk_name(png_ptr, png_ptr->chunk_name);
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
-#endif
-
-   return length;
-}
-
-/* Read data, and (optionally) run it through the CRC. */
-void /* PRIVATE */
-png_crc_read(png_structp png_ptr, png_bytep buf, png_size_t length)
-{
-   if (png_ptr == NULL)
-      return;
-
-   png_read_data(png_ptr, buf, length);
-   png_calculate_crc(png_ptr, buf, length);
-}
-
-/* Optionally skip data and then check the CRC.  Depending on whether we
- * are reading a ancillary or critical chunk, and how the program has set
- * things up, we may calculate the CRC on the data and print a message.
- * Returns '1' if there was a CRC error, '0' otherwise.
- */
-int /* PRIVATE */
-png_crc_finish(png_structp png_ptr, png_uint_32 skip)
-{
-   png_size_t i;
-   png_size_t istop = png_ptr->zbuf_size;
-
-   for (i = (png_size_t)skip; i > istop; i -= istop)
-   {
-      png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
-   }
-
-   if (i)
-   {
-      png_crc_read(png_ptr, png_ptr->zbuf, i);
-   }
-
-   if (png_crc_error(png_ptr))
-   {
-      if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name) ?
-          !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) :
-          (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE))
-      {
-         png_chunk_warning(png_ptr, "CRC error");
-      }
-
-      else
-      {
-         png_chunk_benign_error(png_ptr, "CRC error");
-         return (0);
-      }
-
-      return (1);
-   }
-
-   return (0);
-}
-
-/* Compare the CRC stored in the PNG file with that calculated by libpng from
- * the data it has read thus far.
- */
-int /* PRIVATE */
-png_crc_error(png_structp png_ptr)
-{
-   png_byte crc_bytes[4];
-   png_uint_32 crc;
-   int need_crc = 1;
-
-   if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name))
-   {
-      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
-          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
-         need_crc = 0;
-   }
-
-   else /* critical */
-   {
-      if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
-         need_crc = 0;
-   }
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
-#endif
-
-   /* The chunk CRC must be serialized in a single I/O call. */
-   png_read_data(png_ptr, crc_bytes, 4);
-
-   if (need_crc)
-   {
-      crc = png_get_uint_32(crc_bytes);
-      return ((int)(crc != png_ptr->crc));
-   }
-
-   else
-      return (0);
-}
-
-#ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
-static png_size_t
-png_inflate(png_structp png_ptr, png_bytep data, png_size_t size,
-    png_bytep output, png_size_t output_size)
-{
-   png_size_t count = 0;
-
-   /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it can't
-    * even necessarily handle 65536 bytes) because the type uInt is "16 bits or
-    * more".  Consequently it is necessary to chunk the input to zlib.  This
-    * code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the maximum value
-    * that can be stored in a uInt.)  It is possible to set ZLIB_IO_MAX to a
-    * lower value in pngpriv.h and this may sometimes have a performance
-    * advantage, because it forces access of the input data to be separated from
-    * at least some of the use by some period of time.
-    */
-   png_ptr->zstream.next_in = data;
-   /* avail_in is set below from 'size' */
-   png_ptr->zstream.avail_in = 0;
-
-   while (1)
-   {
-      int ret, avail;
-
-      /* The setting of 'avail_in' used to be outside the loop; by setting it
-       * inside it is possible to chunk the input to zlib and simply rely on
-       * zlib to advance the 'next_in' pointer.  This allows arbitrary amounts o
-       * data to be passed through zlib at the unavoidable cost of requiring a
-       * window save (memcpy of up to 32768 output bytes) every ZLIB_IO_MAX
-       * input bytes.
-       */
-      if (png_ptr->zstream.avail_in == 0 && size > 0)
-      {
-         if (size <= ZLIB_IO_MAX)
-         {
-            /* The value is less than ZLIB_IO_MAX so the cast is safe: */
-            png_ptr->zstream.avail_in = (uInt)size;
-            size = 0;
-         }
-
-         else
-         {
-            png_ptr->zstream.avail_in = ZLIB_IO_MAX;
-            size -= ZLIB_IO_MAX;
-         }
-      }
-
-      /* Reset the output buffer each time round - we empty it
-       * after every inflate call.
-       */
-      png_ptr->zstream.next_out = png_ptr->zbuf;
-      png_ptr->zstream.avail_out = png_ptr->zbuf_size;
-
-      ret = inflate(&png_ptr->zstream, Z_NO_FLUSH);
-      avail = png_ptr->zbuf_size - png_ptr->zstream.avail_out;
-
-      /* First copy/count any new output - but only if we didn't
-       * get an error code.
-       */
-      if ((ret == Z_OK || ret == Z_STREAM_END) && avail > 0)
-      {
-         png_size_t space = avail; /* > 0, see above */
-
-         if (output != 0 && output_size > count)
-         {
-            png_size_t copy = output_size - count;
-
-            if (space < copy)
-               copy = space;
-
-            png_memcpy(output + count, png_ptr->zbuf, copy);
-         }
-         count += space;
-      }
-
-      if (ret == Z_OK)
-         continue;
-
-      /* Termination conditions - always reset the zstream, it
-       * must be left in inflateInit state.
-       */
-      png_ptr->zstream.avail_in = 0;
-      inflateReset(&png_ptr->zstream);
-
-      if (ret == Z_STREAM_END)
-         return count; /* NOTE: may be zero. */
-
-      /* Now handle the error codes - the API always returns 0
-       * and the error message is dumped into the uncompressed
-       * buffer if available.
-       */
-#     ifdef PNG_WARNINGS_SUPPORTED
-      {
-         png_const_charp msg;
-
-         if (png_ptr->zstream.msg != 0)
-            msg = png_ptr->zstream.msg;
-
-         else switch (ret)
-         {
-            case Z_BUF_ERROR:
-               msg = "Buffer error in compressed datastream";
-               break;
-
-            case Z_DATA_ERROR:
-               msg = "Data error in compressed datastream";
-               break;
-
-            default:
-               msg = "Incomplete compressed datastream";
-               break;
-         }
-
-         png_chunk_warning(png_ptr, msg);
-      }
-#     endif
-
-      /* 0 means an error - notice that this code simply ignores
-       * zero length compressed chunks as a result.
-       */
-      return 0;
-   }
-}
-
-/*
- * Decompress trailing data in a chunk.  The assumption is that chunkdata
- * points at an allocated area holding the contents of a chunk with a
- * trailing compressed part.  What we get back is an allocated area
- * holding the original prefix part and an uncompressed version of the
- * trailing part (the malloc area passed in is freed).
- */
-void /* PRIVATE */
-png_decompress_chunk(png_structp png_ptr, int comp_type,
-    png_size_t chunklength,
-    png_size_t prefix_size, png_size_t *newlength)
-{
-   /* The caller should guarantee this */
-   if (prefix_size > chunklength)
-   {
-      /* The recovery is to delete the chunk. */
-      png_warning(png_ptr, "invalid chunklength");
-      prefix_size = 0; /* To delete everything */
-   }
-
-   else if (comp_type == PNG_COMPRESSION_TYPE_BASE)
-   {
-      png_size_t expanded_size = png_inflate(png_ptr,
-          (png_bytep)(png_ptr->chunkdata + prefix_size),
-          chunklength - prefix_size,
-          0,            /* output */
-          0);           /* output size */
-
-      /* Now check the limits on this chunk - if the limit fails the
-       * compressed data will be removed, the prefix will remain.
-       */
-      if (prefix_size >= (~(png_size_t)0) - 1 ||
-         expanded_size >= (~(png_size_t)0) - 1 - prefix_size
-#ifdef PNG_USER_LIMITS_SUPPORTED
-         || (png_ptr->user_chunk_malloc_max &&
-          (prefix_size + expanded_size >= png_ptr->user_chunk_malloc_max - 1))
-#else
-         || ((PNG_USER_CHUNK_MALLOC_MAX > 0) &&
-          prefix_size + expanded_size >= PNG_USER_CHUNK_MALLOC_MAX - 1)
-#endif
-         )
-         png_warning(png_ptr, "Exceeded size limit while expanding chunk");
-
-      /* If the size is zero either there was an error and a message
-       * has already been output (warning) or the size really is zero
-       * and we have nothing to do - the code will exit through the
-       * error case below.
-       */
-      else if (expanded_size > 0)
-      {
-         /* Success (maybe) - really uncompress the chunk. */
-         png_size_t new_size = 0;
-         png_charp text = (png_charp)png_malloc_warn(png_ptr,
-             prefix_size + expanded_size + 1);
-
-         if (text != NULL)
-         {
-            png_memcpy(text, png_ptr->chunkdata, prefix_size);
-            new_size = png_inflate(png_ptr,
-                (png_bytep)(png_ptr->chunkdata + prefix_size),
-                chunklength - prefix_size,
-                (png_bytep)(text + prefix_size), expanded_size);
-            text[prefix_size + expanded_size] = 0; /* just in case */
-
-            if (new_size == expanded_size)
-            {
-               png_free(png_ptr, png_ptr->chunkdata);
-               png_ptr->chunkdata = text;
-               *newlength = prefix_size + expanded_size;
-               return; /* The success return! */
-            }
-
-            png_warning(png_ptr, "png_inflate logic error");
-            png_free(png_ptr, text);
-         }
-
-         else
-            png_warning(png_ptr, "Not enough memory to decompress chunk");
-      }
-   }
-
-   else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */
-   {
-      PNG_WARNING_PARAMETERS(p)
-      png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, comp_type);
-      png_formatted_warning(png_ptr, p, "Unknown compression type @1");
-
-      /* The recovery is to simply drop the data. */
-   }
-
-   /* Generic error return - leave the prefix, delete the compressed
-    * data, reallocate the chunkdata to remove the potentially large
-    * amount of compressed data.
-    */
-   {
-      png_charp text = (png_charp)png_malloc_warn(png_ptr, prefix_size + 1);
-
-      if (text != NULL)
-      {
-         if (prefix_size > 0)
-            png_memcpy(text, png_ptr->chunkdata, prefix_size);
-
-         png_free(png_ptr, png_ptr->chunkdata);
-         png_ptr->chunkdata = text;
-
-         /* This is an extra zero in the 'uncompressed' part. */
-         *(png_ptr->chunkdata + prefix_size) = 0x00;
-      }
-      /* Ignore a malloc error here - it is safe. */
-   }
-
-   *newlength = prefix_size;
-}
-#endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */
-
-/* Read and check the IDHR chunk */
-void /* PRIVATE */
-png_handle_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_byte buf[13];
-   png_uint_32 width, height;
-   int bit_depth, color_type, compression_type, filter_type;
-   int interlace_type;
-
-   png_debug(1, "in png_handle_IHDR");
-
-   if (png_ptr->mode & PNG_HAVE_IHDR)
-      png_error(png_ptr, "Out of place IHDR");
-
-   /* Check the length */
-   if (length != 13)
-      png_error(png_ptr, "Invalid IHDR chunk");
-
-   png_ptr->mode |= PNG_HAVE_IHDR;
-
-   png_crc_read(png_ptr, buf, 13);
-   png_crc_finish(png_ptr, 0);
-
-   width = png_get_uint_31(png_ptr, buf);
-   height = png_get_uint_31(png_ptr, buf + 4);
-   bit_depth = buf[8];
-   color_type = buf[9];
-   compression_type = buf[10];
-   filter_type = buf[11];
-   interlace_type = buf[12];
-
-   /* Set internal variables */
-   png_ptr->width = width;
-   png_ptr->height = height;
-   png_ptr->bit_depth = (png_byte)bit_depth;
-   png_ptr->interlaced = (png_byte)interlace_type;
-   png_ptr->color_type = (png_byte)color_type;
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-   png_ptr->filter_type = (png_byte)filter_type;
-#endif
-   png_ptr->compression_type = (png_byte)compression_type;
-
-   /* Find number of channels */
-   switch (png_ptr->color_type)
-   {
-      default: /* invalid, png_set_IHDR calls png_error */
-      case PNG_COLOR_TYPE_GRAY:
-      case PNG_COLOR_TYPE_PALETTE:
-         png_ptr->channels = 1;
-         break;
-
-      case PNG_COLOR_TYPE_RGB:
-         png_ptr->channels = 3;
-         break;
-
-      case PNG_COLOR_TYPE_GRAY_ALPHA:
-         png_ptr->channels = 2;
-         break;
-
-      case PNG_COLOR_TYPE_RGB_ALPHA:
-         png_ptr->channels = 4;
-         break;
-   }
-
-   /* Set up other useful info */
-   png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth *
-   png_ptr->channels);
-   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
-   png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
-   png_debug1(3, "channels = %d", png_ptr->channels);
-   png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
-   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
-       color_type, interlace_type, compression_type, filter_type);
-}
-
-/* Read and check the palette */
-void /* PRIVATE */
-png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_color palette[PNG_MAX_PALETTE_LENGTH];
-   int num, i;
-#ifdef PNG_POINTER_INDEXING_SUPPORTED
-   png_colorp pal_ptr;
-#endif
-
-   png_debug(1, "in png_handle_PLTE");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before PLTE");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid PLTE after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (png_ptr->mode & PNG_HAVE_PLTE)
-      png_error(png_ptr, "Duplicate PLTE chunk");
-
-   png_ptr->mode |= PNG_HAVE_PLTE;
-
-   if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
-   {
-      png_warning(png_ptr,
-          "Ignoring PLTE chunk in grayscale PNG");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-#ifndef PNG_READ_OPT_PLTE_SUPPORTED
-   if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
-   {
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-#endif
-
-   if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
-   {
-      if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
-      {
-         png_warning(png_ptr, "Invalid palette chunk");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      else
-      {
-         png_error(png_ptr, "Invalid palette chunk");
-      }
-   }
-
-   num = (int)length / 3;
-
-#ifdef PNG_POINTER_INDEXING_SUPPORTED
-   for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
-   {
-      png_byte buf[3];
-
-      png_crc_read(png_ptr, buf, 3);
-      pal_ptr->red = buf[0];
-      pal_ptr->green = buf[1];
-      pal_ptr->blue = buf[2];
-   }
-#else
-   for (i = 0; i < num; i++)
-   {
-      png_byte buf[3];
-
-      png_crc_read(png_ptr, buf, 3);
-      /* Don't depend upon png_color being any order */
-      palette[i].red = buf[0];
-      palette[i].green = buf[1];
-      palette[i].blue = buf[2];
-   }
-#endif
-
-   /* If we actually need the PLTE chunk (ie for a paletted image), we do
-    * whatever the normal CRC configuration tells us.  However, if we
-    * have an RGB image, the PLTE can be considered ancillary, so
-    * we will act as though it is.
-    */
-#ifndef PNG_READ_OPT_PLTE_SUPPORTED
-   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-#endif
-   {
-      png_crc_finish(png_ptr, 0);
-   }
-
-#ifndef PNG_READ_OPT_PLTE_SUPPORTED
-   else if (png_crc_error(png_ptr))  /* Only if we have a CRC error */
-   {
-      /* If we don't want to use the data from an ancillary chunk,
-       * we have two options: an error abort, or a warning and we
-       * ignore the data in this chunk (which should be OK, since
-       * it's considered ancillary for a RGB or RGBA image).
-       */
-      if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE))
-      {
-         if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)
-         {
-            png_chunk_benign_error(png_ptr, "CRC error");
-         }
-
-         else
-         {
-            png_chunk_warning(png_ptr, "CRC error");
-            return;
-         }
-      }
-
-      /* Otherwise, we (optionally) emit a warning and use the chunk. */
-      else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN))
-      {
-         png_chunk_warning(png_ptr, "CRC error");
-      }
-   }
-#endif
-
-   png_set_PLTE(png_ptr, info_ptr, palette, num);
-
-#ifdef PNG_READ_tRNS_SUPPORTED
-   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
-      {
-         if (png_ptr->num_trans > (png_uint_16)num)
-         {
-            png_warning(png_ptr, "Truncating incorrect tRNS chunk length");
-            png_ptr->num_trans = (png_uint_16)num;
-         }
-
-         if (info_ptr->num_trans > (png_uint_16)num)
-         {
-            png_warning(png_ptr, "Truncating incorrect info tRNS chunk length");
-            info_ptr->num_trans = (png_uint_16)num;
-         }
-      }
-   }
-#endif
-
-}
-
-void /* PRIVATE */
-png_handle_IEND(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_debug(1, "in png_handle_IEND");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT))
-   {
-      png_error(png_ptr, "No image in file");
-   }
-
-   png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
-
-   if (length != 0)
-   {
-      png_warning(png_ptr, "Incorrect IEND chunk length");
-   }
-
-   png_crc_finish(png_ptr, length);
-
-   PNG_UNUSED(info_ptr) /* Quiet compiler warnings about unused info_ptr */
-}
-
-#ifdef PNG_READ_gAMA_SUPPORTED
-void /* PRIVATE */
-png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_fixed_point igamma;
-   png_byte buf[4];
-
-   png_debug(1, "in png_handle_gAMA");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before gAMA");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid gAMA after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (png_ptr->mode & PNG_HAVE_PLTE)
-      /* Should be an error, but we can cope with it */
-      png_warning(png_ptr, "Out of place gAMA chunk");
-
-   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
-#ifdef PNG_READ_sRGB_SUPPORTED
-       && !(info_ptr->valid & PNG_INFO_sRGB)
-#endif
-       )
-   {
-      png_warning(png_ptr, "Duplicate gAMA chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (length != 4)
-   {
-      png_warning(png_ptr, "Incorrect gAMA chunk length");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_crc_read(png_ptr, buf, 4);
-
-   if (png_crc_finish(png_ptr, 0))
-      return;
-
-   igamma = png_get_fixed_point(NULL, buf);
-
-   /* Check for zero gamma or an error. */
-   if (igamma <= 0)
-   {
-      png_warning(png_ptr,
-          "Ignoring gAMA chunk with out of range gamma");
-
-      return;
-   }
-
-#  ifdef PNG_READ_sRGB_SUPPORTED
-   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
-   {
-      if (PNG_OUT_OF_RANGE(igamma, 45500, 500))
-      {
-         PNG_WARNING_PARAMETERS(p)
-         png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, igamma);
-         png_formatted_warning(png_ptr, p,
-             "Ignoring incorrect gAMA value @1 when sRGB is also present");
-         return;
-      }
-   }
-#  endif /* PNG_READ_sRGB_SUPPORTED */
-
-#  ifdef PNG_READ_GAMMA_SUPPORTED
-   /* Gamma correction on read is supported. */
-   png_ptr->gamma = igamma;
-#  endif
-   /* And set the 'info' structure members. */
-   png_set_gAMA_fixed(png_ptr, info_ptr, igamma);
-}
-#endif
-
-#ifdef PNG_READ_sBIT_SUPPORTED
-void /* PRIVATE */
-png_handle_sBIT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_size_t truelen;
-   png_byte buf[4];
-
-   png_debug(1, "in png_handle_sBIT");
-
-   buf[0] = buf[1] = buf[2] = buf[3] = 0;
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before sBIT");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid sBIT after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (png_ptr->mode & PNG_HAVE_PLTE)
-   {
-      /* Should be an error, but we can cope with it */
-      png_warning(png_ptr, "Out of place sBIT chunk");
-   }
-
-   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT))
-   {
-      png_warning(png_ptr, "Duplicate sBIT chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      truelen = 3;
-
-   else
-      truelen = (png_size_t)png_ptr->channels;
-
-   if (length != truelen || length > 4)
-   {
-      png_warning(png_ptr, "Incorrect sBIT chunk length");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_crc_read(png_ptr, buf, truelen);
-
-   if (png_crc_finish(png_ptr, 0))
-      return;
-
-   if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
-   {
-      png_ptr->sig_bit.red = buf[0];
-      png_ptr->sig_bit.green = buf[1];
-      png_ptr->sig_bit.blue = buf[2];
-      png_ptr->sig_bit.alpha = buf[3];
-   }
-
-   else
-   {
-      png_ptr->sig_bit.gray = buf[0];
-      png_ptr->sig_bit.red = buf[0];
-      png_ptr->sig_bit.green = buf[0];
-      png_ptr->sig_bit.blue = buf[0];
-      png_ptr->sig_bit.alpha = buf[1];
-   }
-
-   png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
-}
-#endif
-
-#ifdef PNG_READ_cHRM_SUPPORTED
-void /* PRIVATE */
-png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_byte buf[32];
-   png_fixed_point x_white, y_white, x_red, y_red, x_green, y_green, x_blue,
-      y_blue;
-
-   png_debug(1, "in png_handle_cHRM");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before cHRM");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid cHRM after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (png_ptr->mode & PNG_HAVE_PLTE)
-      /* Should be an error, but we can cope with it */
-      png_warning(png_ptr, "Out of place cHRM chunk");
-
-   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM)
-#  ifdef PNG_READ_sRGB_SUPPORTED
-       && !(info_ptr->valid & PNG_INFO_sRGB)
-#  endif
-      )
-   {
-      png_warning(png_ptr, "Duplicate cHRM chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (length != 32)
-   {
-      png_warning(png_ptr, "Incorrect cHRM chunk length");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_crc_read(png_ptr, buf, 32);
-
-   if (png_crc_finish(png_ptr, 0))
-      return;
-
-   x_white = png_get_fixed_point(NULL, buf);
-   y_white = png_get_fixed_point(NULL, buf + 4);
-   x_red   = png_get_fixed_point(NULL, buf + 8);
-   y_red   = png_get_fixed_point(NULL, buf + 12);
-   x_green = png_get_fixed_point(NULL, buf + 16);
-   y_green = png_get_fixed_point(NULL, buf + 20);
-   x_blue  = png_get_fixed_point(NULL, buf + 24);
-   y_blue  = png_get_fixed_point(NULL, buf + 28);
-
-   if (x_white == PNG_FIXED_ERROR ||
-       y_white == PNG_FIXED_ERROR ||
-       x_red   == PNG_FIXED_ERROR ||
-       y_red   == PNG_FIXED_ERROR ||
-       x_green == PNG_FIXED_ERROR ||
-       y_green == PNG_FIXED_ERROR ||
-       x_blue  == PNG_FIXED_ERROR ||
-       y_blue  == PNG_FIXED_ERROR)
-   {
-      png_warning(png_ptr, "Ignoring cHRM chunk with negative chromaticities");
-      return;
-   }
-
-#ifdef PNG_READ_sRGB_SUPPORTED
-   if ((info_ptr != NULL) && (info_ptr->valid & PNG_INFO_sRGB))
-   {
-      if (PNG_OUT_OF_RANGE(x_white, 31270,  1000) ||
-          PNG_OUT_OF_RANGE(y_white, 32900,  1000) ||
-          PNG_OUT_OF_RANGE(x_red,   64000,  1000) ||
-          PNG_OUT_OF_RANGE(y_red,   33000,  1000) ||
-          PNG_OUT_OF_RANGE(x_green, 30000,  1000) ||
-          PNG_OUT_OF_RANGE(y_green, 60000,  1000) ||
-          PNG_OUT_OF_RANGE(x_blue,  15000,  1000) ||
-          PNG_OUT_OF_RANGE(y_blue,   6000,  1000))
-      {
-         PNG_WARNING_PARAMETERS(p)
-
-         png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, x_white);
-         png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_fixed, y_white);
-         png_warning_parameter_signed(p, 3, PNG_NUMBER_FORMAT_fixed, x_red);
-         png_warning_parameter_signed(p, 4, PNG_NUMBER_FORMAT_fixed, y_red);
-         png_warning_parameter_signed(p, 5, PNG_NUMBER_FORMAT_fixed, x_green);
-         png_warning_parameter_signed(p, 6, PNG_NUMBER_FORMAT_fixed, y_green);
-         png_warning_parameter_signed(p, 7, PNG_NUMBER_FORMAT_fixed, x_blue);
-         png_warning_parameter_signed(p, 8, PNG_NUMBER_FORMAT_fixed, y_blue);
-
-         png_formatted_warning(png_ptr, p,
-             "Ignoring incorrect cHRM white(@1,@2) r(@3,@4)g(@5,@6)b(@7,@8) "
-             "when sRGB is also present");
-      }
-      return;
-   }
-#endif /* PNG_READ_sRGB_SUPPORTED */
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   /* Store the _white values as default coefficients for the rgb to gray
-    * operation if it is supported.  Check if the transform is already set to
-    * avoid destroying the transform values.
-    */
-   if (!png_ptr->rgb_to_gray_coefficients_set)
-   {
-      /* png_set_background has not been called and we haven't seen an sRGB
-       * chunk yet.  Find the XYZ of the three end points.
-       */
-      png_XYZ XYZ;
-      png_xy xy;
-
-      xy.redx = x_red;
-      xy.redy = y_red;
-      xy.greenx = x_green;
-      xy.greeny = y_green;
-      xy.bluex = x_blue;
-      xy.bluey = y_blue;
-      xy.whitex = x_white;
-      xy.whitey = y_white;
-
-      if (png_XYZ_from_xy_checked(png_ptr, &XYZ, xy))
-      {
-         /* The success case, because XYZ_from_xy normalises to a reference
-          * white Y of 1.0 we just need to scale the numbers.  This should
-          * always work just fine. It is an internal error if this overflows.
-          */
-         {
-            png_fixed_point r, g, b;
-            if (png_muldiv(&r, XYZ.redY, 32768, PNG_FP_1) &&
-               r >= 0 && r <= 32768 &&
-               png_muldiv(&g, XYZ.greenY, 32768, PNG_FP_1) &&
-               g >= 0 && g <= 32768 &&
-               png_muldiv(&b, XYZ.blueY, 32768, PNG_FP_1) &&
-               b >= 0 && b <= 32768 &&
-               r+g+b <= 32769)
-            {
-               /* We allow 0 coefficients here.  r+g+b may be 32769 if two or
-                * all of the coefficients were rounded up.  Handle this by
-                * reducing the *largest* coefficient by 1; this matches the
-                * approach used for the default coefficients in pngrtran.c
-                */
-               int add = 0;
-
-               if (r+g+b > 32768)
-                  add = -1;
-               else if (r+g+b < 32768)
-                  add = 1;
-
-               if (add != 0)
-               {
-                  if (g >= r && g >= b)
-                     g += add;
-                  else if (r >= g && r >= b)
-                     r += add;
-                  else
-                     b += add;
-               }
-
-               /* Check for an internal error. */
-               if (r+g+b != 32768)
-                  png_error(png_ptr,
-                     "internal error handling cHRM coefficients");
-
-               png_ptr->rgb_to_gray_red_coeff   = (png_uint_16)r;
-               png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
-            }
-
-            /* This is a png_error at present even though it could be ignored -
-             * it should never happen, but it is important that if it does, the
-             * bug is fixed.
-             */
-            else
-               png_error(png_ptr, "internal error handling cHRM->XYZ");
-         }
-      }
-   }
-#endif
-
-   png_set_cHRM_fixed(png_ptr, info_ptr, x_white, y_white, x_red, y_red,
-      x_green, y_green, x_blue, y_blue);
-}
-#endif
-
-#ifdef PNG_READ_sRGB_SUPPORTED
-void /* PRIVATE */
-png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   int intent;
-   png_byte buf[1];
-
-   png_debug(1, "in png_handle_sRGB");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before sRGB");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid sRGB after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (png_ptr->mode & PNG_HAVE_PLTE)
-      /* Should be an error, but we can cope with it */
-      png_warning(png_ptr, "Out of place sRGB chunk");
-
-   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
-   {
-      png_warning(png_ptr, "Duplicate sRGB chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (length != 1)
-   {
-      png_warning(png_ptr, "Incorrect sRGB chunk length");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_crc_read(png_ptr, buf, 1);
-
-   if (png_crc_finish(png_ptr, 0))
-      return;
-
-   intent = buf[0];
-
-   /* Check for bad intent */
-   if (intent >= PNG_sRGB_INTENT_LAST)
-   {
-      png_warning(png_ptr, "Unknown sRGB intent");
-      return;
-   }
-
-#if defined(PNG_READ_gAMA_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
-   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA))
-   {
-      if (PNG_OUT_OF_RANGE(info_ptr->gamma, 45500, 500))
-      {
-         PNG_WARNING_PARAMETERS(p)
-
-         png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed,
-            info_ptr->gamma);
-
-         png_formatted_warning(png_ptr, p,
-             "Ignoring incorrect gAMA value @1 when sRGB is also present");
-      }
-   }
-#endif /* PNG_READ_gAMA_SUPPORTED */
-
-#ifdef PNG_READ_cHRM_SUPPORTED
-   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
-      if (PNG_OUT_OF_RANGE(info_ptr->x_white, 31270,  1000) ||
-          PNG_OUT_OF_RANGE(info_ptr->y_white, 32900,  1000) ||
-          PNG_OUT_OF_RANGE(info_ptr->x_red,   64000,  1000) ||
-          PNG_OUT_OF_RANGE(info_ptr->y_red,   33000,  1000) ||
-          PNG_OUT_OF_RANGE(info_ptr->x_green, 30000,  1000) ||
-          PNG_OUT_OF_RANGE(info_ptr->y_green, 60000,  1000) ||
-          PNG_OUT_OF_RANGE(info_ptr->x_blue,  15000,  1000) ||
-          PNG_OUT_OF_RANGE(info_ptr->y_blue,   6000,  1000))
-      {
-         png_warning(png_ptr,
-             "Ignoring incorrect cHRM value when sRGB is also present");
-      }
-#endif /* PNG_READ_cHRM_SUPPORTED */
-
-   /* This is recorded for use when handling the cHRM chunk above.  An sRGB
-    * chunk unconditionally overwrites the coefficients for grayscale conversion
-    * too.
-    */
-   png_ptr->is_sRGB = 1;
-
-#  ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-      /* Don't overwrite user supplied values: */
-      if (!png_ptr->rgb_to_gray_coefficients_set)
-      {
-         /* These numbers come from the sRGB specification (or, since one has to
-          * pay much money to get a copy, the wikipedia sRGB page) the
-          * chromaticity values quoted have been inverted to get the reverse
-          * transformation from RGB to XYZ and the 'Y' coefficients scaled by
-          * 32768 (then rounded).
-          *
-          * sRGB and ITU Rec-709 both truncate the values for the D65 white
-          * point to four digits and, even though it actually stores five
-          * digits, the PNG spec gives the truncated value.
-          *
-          * This means that when the chromaticities are converted back to XYZ
-          * end points we end up with (6968,23435,2366), which, as described in
-          * pngrtran.c, would overflow.  If the five digit precision and up is
-          * used we get, instead:
-          *
-          *    6968*R + 23435*G + 2365*B
-          *
-          * (Notice that this rounds the blue coefficient down, rather than the
-          * choice used in pngrtran.c which is to round the green one down.)
-          */
-         png_ptr->rgb_to_gray_red_coeff   =  6968; /* 0.212639005871510 */
-         png_ptr->rgb_to_gray_green_coeff = 23434; /* 0.715168678767756 */
-         /* png_ptr->rgb_to_gray_blue_coeff  =  2366; 0.072192315360734	*/
-
-         /* The following keeps the cHRM chunk from destroying the
-          * coefficients again in the event that it follows the sRGB chunk.
-          */
-         png_ptr->rgb_to_gray_coefficients_set = 1;
-      }
-#  endif
-
-   png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, intent);
-}
-#endif /* PNG_READ_sRGB_SUPPORTED */
-
-#ifdef PNG_READ_iCCP_SUPPORTED
-void /* PRIVATE */
-png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-/* Note: this does not properly handle chunks that are > 64K under DOS */
-{
-   png_byte compression_type;
-   png_bytep pC;
-   png_charp profile;
-   png_uint_32 skip = 0;
-   png_uint_32 profile_size;
-   png_alloc_size_t profile_length;
-   png_size_t slength, prefix_length, data_length;
-
-   png_debug(1, "in png_handle_iCCP");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before iCCP");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid iCCP after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (png_ptr->mode & PNG_HAVE_PLTE)
-      /* Should be an error, but we can cope with it */
-      png_warning(png_ptr, "Out of place iCCP chunk");
-
-   if ((png_ptr->mode & PNG_HAVE_iCCP) || (info_ptr != NULL &&
-      (info_ptr->valid & (PNG_INFO_iCCP|PNG_INFO_sRGB))))
-   {
-      png_warning(png_ptr, "Duplicate iCCP chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_ptr->mode |= PNG_HAVE_iCCP;
-
-#ifdef PNG_MAX_MALLOC_64K
-   if (length > (png_uint_32)65535L)
-   {
-      png_warning(png_ptr, "iCCP chunk too large to fit in memory");
-      skip = length - (png_uint_32)65535L;
-      length = (png_uint_32)65535L;
-   }
-#endif
-
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1);
-   slength = length;
-   png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
-
-   if (png_crc_finish(png_ptr, skip))
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   png_ptr->chunkdata[slength] = 0x00;
-
-   for (profile = png_ptr->chunkdata; *profile; profile++)
-      /* Empty loop to find end of name */ ;
-
-   ++profile;
-
-   /* There should be at least one zero (the compression type byte)
-    * following the separator, and we should be on it
-    */
-   if (profile >= png_ptr->chunkdata + slength - 1)
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      png_warning(png_ptr, "Malformed iCCP chunk");
-      return;
-   }
-
-   /* Compression_type should always be zero */
-   compression_type = *profile++;
-
-   if (compression_type)
-   {
-      png_warning(png_ptr, "Ignoring nonzero compression type in iCCP chunk");
-      compression_type = 0x00;  /* Reset it to zero (libpng-1.0.6 through 1.0.8
-                                 wrote nonzero) */
-   }
-
-   prefix_length = profile - png_ptr->chunkdata;
-   png_decompress_chunk(png_ptr, compression_type,
-       slength, prefix_length, &data_length);
-
-   profile_length = data_length - prefix_length;
-
-   if (prefix_length > data_length || profile_length < 4)
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      png_warning(png_ptr, "Profile size field missing from iCCP chunk");
-      return;
-   }
-
-   /* Check the profile_size recorded in the first 32 bits of the ICC profile */
-   pC = (png_bytep)(png_ptr->chunkdata + prefix_length);
-   profile_size = ((*(pC    )) << 24) |
-                  ((*(pC + 1)) << 16) |
-                  ((*(pC + 2)) <<  8) |
-                  ((*(pC + 3))      );
-
-   /* NOTE: the following guarantees that 'profile_length' fits into 32 bits,
-    * because profile_size is a 32 bit value.
-    */
-   if (profile_size < profile_length)
-      profile_length = profile_size;
-
-   /* And the following guarantees that profile_size == profile_length. */
-   if (profile_size > profile_length)
-   {
-      PNG_WARNING_PARAMETERS(p)
-
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-
-      png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_u, profile_size);
-      png_warning_parameter_unsigned(p, 2, PNG_NUMBER_FORMAT_u, profile_length);
-      png_formatted_warning(png_ptr, p,
-         "Ignoring iCCP chunk with declared size = @1 and actual length = @2");
-      return;
-   }
-
-   png_set_iCCP(png_ptr, info_ptr, png_ptr->chunkdata,
-       compression_type, (png_bytep)png_ptr->chunkdata + prefix_length,
-       profile_size);
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = NULL;
-}
-#endif /* PNG_READ_iCCP_SUPPORTED */
-
-#ifdef PNG_READ_sPLT_SUPPORTED
-void /* PRIVATE */
-png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-/* Note: this does not properly handle chunks that are > 64K under DOS */
-{
-   png_bytep entry_start;
-   png_sPLT_t new_palette;
-   png_sPLT_entryp pp;
-   png_uint_32 data_length;
-   int entry_size, i;
-   png_uint_32 skip = 0;
-   png_size_t slength;
-   png_uint_32 dl;
-   png_size_t max_dl;
-
-   png_debug(1, "in png_handle_sPLT");
-
-#ifdef PNG_USER_LIMITS_SUPPORTED
-
-   if (png_ptr->user_chunk_cache_max != 0)
-   {
-      if (png_ptr->user_chunk_cache_max == 1)
-      {
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      if (--png_ptr->user_chunk_cache_max == 1)
-      {
-         png_warning(png_ptr, "No space in chunk cache for sPLT");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-   }
-#endif
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before sPLT");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid sPLT after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-#ifdef PNG_MAX_MALLOC_64K
-   if (length > (png_uint_32)65535L)
-   {
-      png_warning(png_ptr, "sPLT chunk too large to fit in memory");
-      skip = length - (png_uint_32)65535L;
-      length = (png_uint_32)65535L;
-   }
-#endif
-
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1);
-
-   /* WARNING: this may break if size_t is less than 32 bits; it is assumed
-    * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
-    * potential breakage point if the types in pngconf.h aren't exactly right.
-    */
-   slength = length;
-   png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
-
-   if (png_crc_finish(png_ptr, skip))
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   png_ptr->chunkdata[slength] = 0x00;
-
-   for (entry_start = (png_bytep)png_ptr->chunkdata; *entry_start;
-       entry_start++)
-      /* Empty loop to find end of name */ ;
-
-   ++entry_start;
-
-   /* A sample depth should follow the separator, and we should be on it  */
-   if (entry_start > (png_bytep)png_ptr->chunkdata + slength - 2)
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      png_warning(png_ptr, "malformed sPLT chunk");
-      return;
-   }
-
-   new_palette.depth = *entry_start++;
-   entry_size = (new_palette.depth == 8 ? 6 : 10);
-   /* This must fit in a png_uint_32 because it is derived from the original
-    * chunk data length (and use 'length', not 'slength' here for clarity -
-    * they are guaranteed to be the same, see the tests above.)
-    */
-   data_length = length - (png_uint_32)(entry_start -
-      (png_bytep)png_ptr->chunkdata);
-
-   /* Integrity-check the data length */
-   if (data_length % entry_size)
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      png_warning(png_ptr, "sPLT chunk has bad length");
-      return;
-   }
-
-   dl = (png_int_32)(data_length / entry_size);
-   max_dl = PNG_SIZE_MAX / png_sizeof(png_sPLT_entry);
-
-   if (dl > max_dl)
-   {
-       png_warning(png_ptr, "sPLT chunk too long");
-       return;
-   }
-
-   new_palette.nentries = (png_int_32)(data_length / entry_size);
-
-   new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
-       png_ptr, new_palette.nentries * png_sizeof(png_sPLT_entry));
-
-   if (new_palette.entries == NULL)
-   {
-       png_warning(png_ptr, "sPLT chunk requires too much memory");
-       return;
-   }
-
-#ifdef PNG_POINTER_INDEXING_SUPPORTED
-   for (i = 0; i < new_palette.nentries; i++)
-   {
-      pp = new_palette.entries + i;
-
-      if (new_palette.depth == 8)
-      {
-         pp->red = *entry_start++;
-         pp->green = *entry_start++;
-         pp->blue = *entry_start++;
-         pp->alpha = *entry_start++;
-      }
-
-      else
-      {
-         pp->red   = png_get_uint_16(entry_start); entry_start += 2;
-         pp->green = png_get_uint_16(entry_start); entry_start += 2;
-         pp->blue  = png_get_uint_16(entry_start); entry_start += 2;
-         pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
-      }
-
-      pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
-   }
-#else
-   pp = new_palette.entries;
-
-   for (i = 0; i < new_palette.nentries; i++)
-   {
-
-      if (new_palette.depth == 8)
-      {
-         pp[i].red   = *entry_start++;
-         pp[i].green = *entry_start++;
-         pp[i].blue  = *entry_start++;
-         pp[i].alpha = *entry_start++;
-      }
-
-      else
-      {
-         pp[i].red   = png_get_uint_16(entry_start); entry_start += 2;
-         pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
-         pp[i].blue  = png_get_uint_16(entry_start); entry_start += 2;
-         pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
-      }
-
-      pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
-   }
-#endif
-
-   /* Discard all chunk data except the name and stash that */
-   new_palette.name = png_ptr->chunkdata;
-
-   png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
-
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = NULL;
-   png_free(png_ptr, new_palette.entries);
-}
-#endif /* PNG_READ_sPLT_SUPPORTED */
-
-#ifdef PNG_READ_tRNS_SUPPORTED
-void /* PRIVATE */
-png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
-
-   png_debug(1, "in png_handle_tRNS");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before tRNS");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid tRNS after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
-   {
-      png_warning(png_ptr, "Duplicate tRNS chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
-   {
-      png_byte buf[2];
-
-      if (length != 2)
-      {
-         png_warning(png_ptr, "Incorrect tRNS chunk length");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      png_crc_read(png_ptr, buf, 2);
-      png_ptr->num_trans = 1;
-      png_ptr->trans_color.gray = png_get_uint_16(buf);
-   }
-
-   else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
-   {
-      png_byte buf[6];
-
-      if (length != 6)
-      {
-         png_warning(png_ptr, "Incorrect tRNS chunk length");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      png_crc_read(png_ptr, buf, (png_size_t)length);
-      png_ptr->num_trans = 1;
-      png_ptr->trans_color.red = png_get_uint_16(buf);
-      png_ptr->trans_color.green = png_get_uint_16(buf + 2);
-      png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
-   }
-
-   else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      if (!(png_ptr->mode & PNG_HAVE_PLTE))
-      {
-         /* Should be an error, but we can cope with it. */
-         png_warning(png_ptr, "Missing PLTE before tRNS");
-      }
-
-      if (length > (png_uint_32)png_ptr->num_palette ||
-          length > PNG_MAX_PALETTE_LENGTH)
-      {
-         png_warning(png_ptr, "Incorrect tRNS chunk length");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      if (length == 0)
-      {
-         png_warning(png_ptr, "Zero length tRNS chunk");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      png_crc_read(png_ptr, readbuf, (png_size_t)length);
-      png_ptr->num_trans = (png_uint_16)length;
-   }
-
-   else
-   {
-      png_warning(png_ptr, "tRNS chunk not allowed with alpha channel");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (png_crc_finish(png_ptr, 0))
-   {
-      png_ptr->num_trans = 0;
-      return;
-   }
-
-   png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
-       &(png_ptr->trans_color));
-}
-#endif
-
-#ifdef PNG_READ_bKGD_SUPPORTED
-void /* PRIVATE */
-png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_size_t truelen;
-   png_byte buf[6];
-   png_color_16 background;
-
-   png_debug(1, "in png_handle_bKGD");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before bKGD");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid bKGD after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-       !(png_ptr->mode & PNG_HAVE_PLTE))
-   {
-      png_warning(png_ptr, "Missing PLTE before bKGD");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD))
-   {
-      png_warning(png_ptr, "Duplicate bKGD chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      truelen = 1;
-
-   else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
-      truelen = 6;
-
-   else
-      truelen = 2;
-
-   if (length != truelen)
-   {
-      png_warning(png_ptr, "Incorrect bKGD chunk length");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_crc_read(png_ptr, buf, truelen);
-
-   if (png_crc_finish(png_ptr, 0))
-      return;
-
-   /* We convert the index value into RGB components so that we can allow
-    * arbitrary RGB values for background when we have transparency, and
-    * so it is easy to determine the RGB values of the background color
-    * from the info_ptr struct.
-    */
-   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      background.index = buf[0];
-
-      if (info_ptr && info_ptr->num_palette)
-      {
-         if (buf[0] >= info_ptr->num_palette)
-         {
-            png_warning(png_ptr, "Incorrect bKGD chunk index value");
-            return;
-         }
-
-         background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
-         background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
-         background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
-      }
-
-      else
-         background.red = background.green = background.blue = 0;
-
-      background.gray = 0;
-   }
-
-   else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */
-   {
-      background.index = 0;
-      background.red =
-      background.green =
-      background.blue =
-      background.gray = png_get_uint_16(buf);
-   }
-
-   else
-   {
-      background.index = 0;
-      background.red = png_get_uint_16(buf);
-      background.green = png_get_uint_16(buf + 2);
-      background.blue = png_get_uint_16(buf + 4);
-      background.gray = 0;
-   }
-
-   png_set_bKGD(png_ptr, info_ptr, &background);
-}
-#endif
-
-#ifdef PNG_READ_hIST_SUPPORTED
-void /* PRIVATE */
-png_handle_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   unsigned int num, i;
-   png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
-
-   png_debug(1, "in png_handle_hIST");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before hIST");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid hIST after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (!(png_ptr->mode & PNG_HAVE_PLTE))
-   {
-      png_warning(png_ptr, "Missing PLTE before hIST");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST))
-   {
-      png_warning(png_ptr, "Duplicate hIST chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (length > 2*PNG_MAX_PALETTE_LENGTH ||
-       length != (unsigned int) (2*png_ptr->num_palette))
-   {
-      png_warning(png_ptr, "Incorrect hIST chunk length");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   num = length / 2 ;
-
-   for (i = 0; i < num; i++)
-   {
-      png_byte buf[2];
-
-      png_crc_read(png_ptr, buf, 2);
-      readbuf[i] = png_get_uint_16(buf);
-   }
-
-   if (png_crc_finish(png_ptr, 0))
-      return;
-
-   png_set_hIST(png_ptr, info_ptr, readbuf);
-}
-#endif
-
-#ifdef PNG_READ_pHYs_SUPPORTED
-void /* PRIVATE */
-png_handle_pHYs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_byte buf[9];
-   png_uint_32 res_x, res_y;
-   int unit_type;
-
-   png_debug(1, "in png_handle_pHYs");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before pHYs");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid pHYs after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
-   {
-      png_warning(png_ptr, "Duplicate pHYs chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (length != 9)
-   {
-      png_warning(png_ptr, "Incorrect pHYs chunk length");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_crc_read(png_ptr, buf, 9);
-
-   if (png_crc_finish(png_ptr, 0))
-      return;
-
-   res_x = png_get_uint_32(buf);
-   res_y = png_get_uint_32(buf + 4);
-   unit_type = buf[8];
-   png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
-}
-#endif
-
-#ifdef PNG_READ_oFFs_SUPPORTED
-void /* PRIVATE */
-png_handle_oFFs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_byte buf[9];
-   png_int_32 offset_x, offset_y;
-   int unit_type;
-
-   png_debug(1, "in png_handle_oFFs");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before oFFs");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid oFFs after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
-   {
-      png_warning(png_ptr, "Duplicate oFFs chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (length != 9)
-   {
-      png_warning(png_ptr, "Incorrect oFFs chunk length");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_crc_read(png_ptr, buf, 9);
-
-   if (png_crc_finish(png_ptr, 0))
-      return;
-
-   offset_x = png_get_int_32(buf);
-   offset_y = png_get_int_32(buf + 4);
-   unit_type = buf[8];
-   png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
-}
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-/* Read the pCAL chunk (described in the PNG Extensions document) */
-void /* PRIVATE */
-png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_int_32 X0, X1;
-   png_byte type, nparams;
-   png_charp buf, units, endptr;
-   png_charpp params;
-   png_size_t slength;
-   int i;
-
-   png_debug(1, "in png_handle_pCAL");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before pCAL");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid pCAL after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL))
-   {
-      png_warning(png_ptr, "Duplicate pCAL chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
-       length + 1);
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
-
-   if (png_ptr->chunkdata == NULL)
-   {
-      png_warning(png_ptr, "No memory for pCAL purpose");
-      return;
-   }
-
-   slength = length;
-   png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
-
-   if (png_crc_finish(png_ptr, 0))
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */
-
-   png_debug(3, "Finding end of pCAL purpose string");
-   for (buf = png_ptr->chunkdata; *buf; buf++)
-      /* Empty loop */ ;
-
-   endptr = png_ptr->chunkdata + slength;
-
-   /* We need to have at least 12 bytes after the purpose string
-    * in order to get the parameter information.
-    */
-   if (endptr <= buf + 12)
-   {
-      png_warning(png_ptr, "Invalid pCAL data");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
-   X0 = png_get_int_32((png_bytep)buf+1);
-   X1 = png_get_int_32((png_bytep)buf+5);
-   type = buf[9];
-   nparams = buf[10];
-   units = buf + 11;
-
-   png_debug(3, "Checking pCAL equation type and number of parameters");
-   /* Check that we have the right number of parameters for known
-    * equation types.
-    */
-   if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
-       (type == PNG_EQUATION_BASE_E && nparams != 3) ||
-       (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
-       (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
-   {
-      png_warning(png_ptr, "Invalid pCAL parameters for equation type");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   else if (type >= PNG_EQUATION_LAST)
-   {
-      png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
-   }
-
-   for (buf = units; *buf; buf++)
-      /* Empty loop to move past the units string. */ ;
-
-   png_debug(3, "Allocating pCAL parameters array");
-
-   params = (png_charpp)png_malloc_warn(png_ptr,
-       (png_size_t)(nparams * png_sizeof(png_charp)));
-
-   if (params == NULL)
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      png_warning(png_ptr, "No memory for pCAL params");
-      return;
-   }
-
-   /* Get pointers to the start of each parameter string. */
-   for (i = 0; i < (int)nparams; i++)
-   {
-      buf++; /* Skip the null string terminator from previous parameter. */
-
-      png_debug1(3, "Reading pCAL parameter %d", i);
-
-      for (params[i] = buf; buf <= endptr && *buf != 0x00; buf++)
-         /* Empty loop to move past each parameter string */ ;
-
-      /* Make sure we haven't run out of data yet */
-      if (buf > endptr)
-      {
-         png_warning(png_ptr, "Invalid pCAL data");
-         png_free(png_ptr, png_ptr->chunkdata);
-         png_ptr->chunkdata = NULL;
-         png_free(png_ptr, params);
-         return;
-      }
-   }
-
-   png_set_pCAL(png_ptr, info_ptr, png_ptr->chunkdata, X0, X1, type, nparams,
-      units, params);
-
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = NULL;
-   png_free(png_ptr, params);
-}
-#endif
-
-#ifdef PNG_READ_sCAL_SUPPORTED
-/* Read the sCAL chunk */
-void /* PRIVATE */
-png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_size_t slength, i;
-   int state;
-
-   png_debug(1, "in png_handle_sCAL");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before sCAL");
-
-   else if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      png_warning(png_ptr, "Invalid sCAL after IDAT");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL))
-   {
-      png_warning(png_ptr, "Duplicate sCAL chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   /* Need unit type, width, \0, height: minimum 4 bytes */
-   else if (length < 4)
-   {
-      png_warning(png_ptr, "sCAL chunk too short");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
-      length + 1);
-
-   png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
-
-   if (png_ptr->chunkdata == NULL)
-   {
-      png_warning(png_ptr, "Out of memory while processing sCAL chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   slength = length;
-   png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
-   png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */
-
-   if (png_crc_finish(png_ptr, 0))
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   /* Validate the unit. */
-   if (png_ptr->chunkdata[0] != 1 && png_ptr->chunkdata[0] != 2)
-   {
-      png_warning(png_ptr, "Invalid sCAL ignored: invalid unit");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   /* Validate the ASCII numbers, need two ASCII numbers separated by
-    * a '\0' and they need to fit exactly in the chunk data.
-    */
-   i = 1;
-   state = 0;
-
-   if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
-       i >= slength || png_ptr->chunkdata[i++] != 0)
-      png_warning(png_ptr, "Invalid sCAL chunk ignored: bad width format");
-
-   else if (!PNG_FP_IS_POSITIVE(state))
-      png_warning(png_ptr, "Invalid sCAL chunk ignored: non-positive width");
-
-   else
-   {
-      png_size_t heighti = i;
-
-      state = 0;
-      if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
-          i != slength)
-         png_warning(png_ptr, "Invalid sCAL chunk ignored: bad height format");
-
-      else if (!PNG_FP_IS_POSITIVE(state))
-         png_warning(png_ptr,
-            "Invalid sCAL chunk ignored: non-positive height");
-
-      else
-         /* This is the (only) success case. */
-         png_set_sCAL_s(png_ptr, info_ptr, png_ptr->chunkdata[0],
-            png_ptr->chunkdata+1, png_ptr->chunkdata+heighti);
-   }
-
-   /* Clean up - just free the temporarily allocated buffer. */
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = NULL;
-}
-#endif
-
-#ifdef PNG_READ_tIME_SUPPORTED
-void /* PRIVATE */
-png_handle_tIME(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_byte buf[7];
-   png_time mod_time;
-
-   png_debug(1, "in png_handle_tIME");
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Out of place tIME chunk");
-
-   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME))
-   {
-      png_warning(png_ptr, "Duplicate tIME chunk");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   if (png_ptr->mode & PNG_HAVE_IDAT)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
-   if (length != 7)
-   {
-      png_warning(png_ptr, "Incorrect tIME chunk length");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-
-   png_crc_read(png_ptr, buf, 7);
-
-   if (png_crc_finish(png_ptr, 0))
-      return;
-
-   mod_time.second = buf[6];
-   mod_time.minute = buf[5];
-   mod_time.hour = buf[4];
-   mod_time.day = buf[3];
-   mod_time.month = buf[2];
-   mod_time.year = png_get_uint_16(buf);
-
-   png_set_tIME(png_ptr, info_ptr, &mod_time);
-}
-#endif
-
-#ifdef PNG_READ_tEXt_SUPPORTED
-/* Note: this does not properly handle chunks that are > 64K under DOS */
-void /* PRIVATE */
-png_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_textp text_ptr;
-   png_charp key;
-   png_charp text;
-   png_uint_32 skip = 0;
-   png_size_t slength;
-   int ret;
-
-   png_debug(1, "in png_handle_tEXt");
-
-#ifdef PNG_USER_LIMITS_SUPPORTED
-   if (png_ptr->user_chunk_cache_max != 0)
-   {
-      if (png_ptr->user_chunk_cache_max == 1)
-      {
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      if (--png_ptr->user_chunk_cache_max == 1)
-      {
-         png_warning(png_ptr, "No space in chunk cache for tEXt");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-   }
-#endif
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before tEXt");
-
-   if (png_ptr->mode & PNG_HAVE_IDAT)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
-#ifdef PNG_MAX_MALLOC_64K
-   if (length > (png_uint_32)65535L)
-   {
-      png_warning(png_ptr, "tEXt chunk too large to fit in memory");
-      skip = length - (png_uint_32)65535L;
-      length = (png_uint_32)65535L;
-   }
-#endif
-
-   png_free(png_ptr, png_ptr->chunkdata);
-
-   png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
-
-   if (png_ptr->chunkdata == NULL)
-   {
-     png_warning(png_ptr, "No memory to process text chunk");
-     return;
-   }
-
-   slength = length;
-   png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
-
-   if (png_crc_finish(png_ptr, skip))
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   key = png_ptr->chunkdata;
-
-   key[slength] = 0x00;
-
-   for (text = key; *text; text++)
-      /* Empty loop to find end of key */ ;
-
-   if (text != key + slength)
-      text++;
-
-   text_ptr = (png_textp)png_malloc_warn(png_ptr,
-       png_sizeof(png_text));
-
-   if (text_ptr == NULL)
-   {
-      png_warning(png_ptr, "Not enough memory to process text chunk");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
-   text_ptr->key = key;
-   text_ptr->lang = NULL;
-   text_ptr->lang_key = NULL;
-   text_ptr->itxt_length = 0;
-   text_ptr->text = text;
-   text_ptr->text_length = png_strlen(text);
-
-   ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
-
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = NULL;
-   png_free(png_ptr, text_ptr);
-
-   if (ret)
-      png_warning(png_ptr, "Insufficient memory to process text chunk");
-}
-#endif
-
-#ifdef PNG_READ_zTXt_SUPPORTED
-/* Note: this does not correctly handle chunks that are > 64K under DOS */
-void /* PRIVATE */
-png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_textp text_ptr;
-   png_charp text;
-   int comp_type;
-   int ret;
-   png_size_t slength, prefix_len, data_len;
-
-   png_debug(1, "in png_handle_zTXt");
-
-#ifdef PNG_USER_LIMITS_SUPPORTED
-   if (png_ptr->user_chunk_cache_max != 0)
-   {
-      if (png_ptr->user_chunk_cache_max == 1)
-      {
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      if (--png_ptr->user_chunk_cache_max == 1)
-      {
-         png_warning(png_ptr, "No space in chunk cache for zTXt");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-   }
-#endif
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before zTXt");
-
-   if (png_ptr->mode & PNG_HAVE_IDAT)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
-#ifdef PNG_MAX_MALLOC_64K
-   /* We will no doubt have problems with chunks even half this size, but
-    * there is no hard and fast rule to tell us where to stop.
-    */
-   if (length > (png_uint_32)65535L)
-   {
-      png_warning(png_ptr, "zTXt chunk too large to fit in memory");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-#endif
-
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
-
-   if (png_ptr->chunkdata == NULL)
-   {
-      png_warning(png_ptr, "Out of memory processing zTXt chunk");
-      return;
-   }
-
-   slength = length;
-   png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
-
-   if (png_crc_finish(png_ptr, 0))
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   png_ptr->chunkdata[slength] = 0x00;
-
-   for (text = png_ptr->chunkdata; *text; text++)
-      /* Empty loop */ ;
-
-   /* zTXt must have some text after the chunkdataword */
-   if (text >= png_ptr->chunkdata + slength - 2)
-   {
-      png_warning(png_ptr, "Truncated zTXt chunk");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   else
-   {
-       comp_type = *(++text);
-
-       if (comp_type != PNG_TEXT_COMPRESSION_zTXt)
-       {
-          png_warning(png_ptr, "Unknown compression type in zTXt chunk");
-          comp_type = PNG_TEXT_COMPRESSION_zTXt;
-       }
-
-       text++;        /* Skip the compression_method byte */
-   }
-
-   prefix_len = text - png_ptr->chunkdata;
-
-   png_decompress_chunk(png_ptr, comp_type,
-       (png_size_t)length, prefix_len, &data_len);
-
-   text_ptr = (png_textp)png_malloc_warn(png_ptr,
-       png_sizeof(png_text));
-
-   if (text_ptr == NULL)
-   {
-      png_warning(png_ptr, "Not enough memory to process zTXt chunk");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   text_ptr->compression = comp_type;
-   text_ptr->key = png_ptr->chunkdata;
-   text_ptr->lang = NULL;
-   text_ptr->lang_key = NULL;
-   text_ptr->itxt_length = 0;
-   text_ptr->text = png_ptr->chunkdata + prefix_len;
-   text_ptr->text_length = data_len;
-
-   ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
-
-   png_free(png_ptr, text_ptr);
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = NULL;
-
-   if (ret)
-      png_error(png_ptr, "Insufficient memory to store zTXt chunk");
-}
-#endif
-
-#ifdef PNG_READ_iTXt_SUPPORTED
-/* Note: this does not correctly handle chunks that are > 64K under DOS */
-void /* PRIVATE */
-png_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_textp text_ptr;
-   png_charp key, lang, text, lang_key;
-   int comp_flag;
-   int comp_type = 0;
-   int ret;
-   png_size_t slength, prefix_len, data_len;
-
-   png_debug(1, "in png_handle_iTXt");
-
-#ifdef PNG_USER_LIMITS_SUPPORTED
-   if (png_ptr->user_chunk_cache_max != 0)
-   {
-      if (png_ptr->user_chunk_cache_max == 1)
-      {
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      if (--png_ptr->user_chunk_cache_max == 1)
-      {
-         png_warning(png_ptr, "No space in chunk cache for iTXt");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-   }
-#endif
-
-   if (!(png_ptr->mode & PNG_HAVE_IHDR))
-      png_error(png_ptr, "Missing IHDR before iTXt");
-
-   if (png_ptr->mode & PNG_HAVE_IDAT)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
-#ifdef PNG_MAX_MALLOC_64K
-   /* We will no doubt have problems with chunks even half this size, but
-    * there is no hard and fast rule to tell us where to stop.
-    */
-   if (length > (png_uint_32)65535L)
-   {
-      png_warning(png_ptr, "iTXt chunk too large to fit in memory");
-      png_crc_finish(png_ptr, length);
-      return;
-   }
-#endif
-
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
-
-   if (png_ptr->chunkdata == NULL)
-   {
-      png_warning(png_ptr, "No memory to process iTXt chunk");
-      return;
-   }
-
-   slength = length;
-   png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
-
-   if (png_crc_finish(png_ptr, 0))
-   {
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   png_ptr->chunkdata[slength] = 0x00;
-
-   for (lang = png_ptr->chunkdata; *lang; lang++)
-      /* Empty loop */ ;
-
-   lang++;        /* Skip NUL separator */
-
-   /* iTXt must have a language tag (possibly empty), two compression bytes,
-    * translated keyword (possibly empty), and possibly some text after the
-    * keyword
-    */
-
-   if (lang >= png_ptr->chunkdata + slength - 3)
-   {
-      png_warning(png_ptr, "Truncated iTXt chunk");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   else
-   {
-      comp_flag = *lang++;
-      comp_type = *lang++;
-   }
-
-   if (comp_type || (comp_flag && comp_flag != PNG_TEXT_COMPRESSION_zTXt))
-   {
-      png_warning(png_ptr, "Unknown iTXt compression type or method");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   for (lang_key = lang; *lang_key; lang_key++)
-      /* Empty loop */ ;
-
-   lang_key++;        /* Skip NUL separator */
-
-   if (lang_key >= png_ptr->chunkdata + slength)
-   {
-      png_warning(png_ptr, "Truncated iTXt chunk");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   for (text = lang_key; *text; text++)
-      /* Empty loop */ ;
-
-   text++;        /* Skip NUL separator */
-
-   if (text >= png_ptr->chunkdata + slength)
-   {
-      png_warning(png_ptr, "Malformed iTXt chunk");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   prefix_len = text - png_ptr->chunkdata;
-
-   key=png_ptr->chunkdata;
-
-   if (comp_flag)
-      png_decompress_chunk(png_ptr, comp_type,
-          (size_t)length, prefix_len, &data_len);
-
-   else
-      data_len = png_strlen(png_ptr->chunkdata + prefix_len);
-
-   text_ptr = (png_textp)png_malloc_warn(png_ptr,
-       png_sizeof(png_text));
-
-   if (text_ptr == NULL)
-   {
-      png_warning(png_ptr, "Not enough memory to process iTXt chunk");
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = NULL;
-      return;
-   }
-
-   text_ptr->compression = (int)comp_flag + 1;
-   text_ptr->lang_key = png_ptr->chunkdata + (lang_key - key);
-   text_ptr->lang = png_ptr->chunkdata + (lang - key);
-   text_ptr->itxt_length = data_len;
-   text_ptr->text_length = 0;
-   text_ptr->key = png_ptr->chunkdata;
-   text_ptr->text = png_ptr->chunkdata + prefix_len;
-
-   ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
-
-   png_free(png_ptr, text_ptr);
-   png_free(png_ptr, png_ptr->chunkdata);
-   png_ptr->chunkdata = NULL;
-
-   if (ret)
-      png_error(png_ptr, "Insufficient memory to store iTXt chunk");
-}
-#endif
-
-/* This function is called when we haven't found a handler for a
- * chunk.  If there isn't a problem with the chunk itself (ie bad
- * chunk name, CRC, or a critical chunk), the chunk is silently ignored
- * -- unless the PNG_FLAG_UNKNOWN_CHUNKS_SUPPORTED flag is on in which
- * case it will be saved away to be written out later.
- */
-void /* PRIVATE */
-png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
-{
-   png_uint_32 skip = 0;
-
-   png_debug(1, "in png_handle_unknown");
-
-#ifdef PNG_USER_LIMITS_SUPPORTED
-   if (png_ptr->user_chunk_cache_max != 0)
-   {
-      if (png_ptr->user_chunk_cache_max == 1)
-      {
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-
-      if (--png_ptr->user_chunk_cache_max == 1)
-      {
-         png_warning(png_ptr, "No space in chunk cache for unknown chunk");
-         png_crc_finish(png_ptr, length);
-         return;
-      }
-   }
-#endif
-
-   if (png_ptr->mode & PNG_HAVE_IDAT)
-   {
-      if (png_ptr->chunk_name != png_IDAT)
-         png_ptr->mode |= PNG_AFTER_IDAT;
-   }
-
-   if (PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
-   {
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-      if (png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name) !=
-          PNG_HANDLE_CHUNK_ALWAYS
-#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
-          && png_ptr->read_user_chunk_fn == NULL
-#endif
-          )
-#endif
-         png_chunk_error(png_ptr, "unknown critical chunk");
-   }
-
-#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
-   if ((png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
-#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
-       || (png_ptr->read_user_chunk_fn != NULL)
-#endif
-       )
-   {
-#ifdef PNG_MAX_MALLOC_64K
-      if (length > 65535)
-      {
-         png_warning(png_ptr, "unknown chunk too large to fit in memory");
-         skip = length - 65535;
-         length = 65535;
-      }
-#endif
-
-      /* TODO: this code is very close to the unknown handling in pngpread.c,
-       * maybe it can be put into a common utility routine?
-       * png_struct::unknown_chunk is just used as a temporary variable, along
-       * with the data into which the chunk is read.  These can be eliminated.
-       */
-      PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
-      png_ptr->unknown_chunk.size = (png_size_t)length;
-
-      if (length == 0)
-         png_ptr->unknown_chunk.data = NULL;
-
-      else
-      {
-         png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
-         png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
-      }
-
-#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
-      if (png_ptr->read_user_chunk_fn != NULL)
-      {
-         /* Callback to user unknown chunk handler */
-         int ret;
-
-         ret = (*(png_ptr->read_user_chunk_fn))
-             (png_ptr, &png_ptr->unknown_chunk);
-
-         if (ret < 0)
-            png_chunk_error(png_ptr, "error in user chunk");
-
-         if (ret == 0)
-         {
-            if (PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
-            {
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-               if (png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name) !=
-                   PNG_HANDLE_CHUNK_ALWAYS)
-#endif
-                  png_chunk_error(png_ptr, "unknown critical chunk");
-            }
-
-            png_set_unknown_chunks(png_ptr, info_ptr,
-                &png_ptr->unknown_chunk, 1);
-         }
-      }
-
-      else
-#endif
-         png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
-
-      png_free(png_ptr, png_ptr->unknown_chunk.data);
-      png_ptr->unknown_chunk.data = NULL;
-   }
-
-   else
-#endif
-      skip = length;
-
-   png_crc_finish(png_ptr, skip);
-
-#ifndef PNG_READ_USER_CHUNKS_SUPPORTED
-   PNG_UNUSED(info_ptr) /* Quiet compiler warnings about unused info_ptr */
-#endif
-}
-
-/* This function is called to verify that a chunk name is valid.
- * This function can't have the "critical chunk check" incorporated
- * into it, since in the future we will need to be able to call user
- * functions to handle unknown critical chunks after we check that
- * the chunk name itself is valid.
- */
-
-/* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
- *
- * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
- */
-
-void /* PRIVATE */
-png_check_chunk_name(png_structp png_ptr, png_uint_32 chunk_name)
-{
-   int i;
-
-   png_debug(1, "in png_check_chunk_name");
-
-   for (i=1; i<=4; ++i)
-   {
-      int c = chunk_name & 0xff;
-
-      if (c < 65 || c > 122 || (c > 90 && c < 97))
-         png_chunk_error(png_ptr, "invalid chunk type");
-
-      chunk_name >>= 8;
-   }
-}
-
-/* Combines the row recently read in with the existing pixels in the row.  This
- * routine takes care of alpha and transparency if requested.  This routine also
- * handles the two methods of progressive display of interlaced images,
- * depending on the 'display' value; if 'display' is true then the whole row
- * (dp) is filled from the start by replicating the available pixels.  If
- * 'display' is false only those pixels present in the pass are filled in.
- */
-void /* PRIVATE */
-png_combine_row(png_structp png_ptr, png_bytep dp, int display)
-{
-   unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
-   png_const_bytep sp = png_ptr->row_buf + 1;
-   png_uint_32 row_width = png_ptr->width;
-   unsigned int pass = png_ptr->pass;
-   png_bytep end_ptr = 0;
-   png_byte end_byte = 0;
-   unsigned int end_mask;
-
-   png_debug(1, "in png_combine_row");
-
-   /* Added in 1.5.6: it should not be possible to enter this routine until at
-    * least one row has been read from the PNG data and transformed.
-    */
-   if (pixel_depth == 0)
-      png_error(png_ptr, "internal row logic error");
-
-   /* Added in 1.5.4: the pixel depth should match the information returned by
-    * any call to png_read_update_info at this point.  Do not continue if we got
-    * this wrong.
-    */
-   if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
-          PNG_ROWBYTES(pixel_depth, row_width))
-      png_error(png_ptr, "internal row size calculation error");
-
-   /* Don't expect this to ever happen: */
-   if (row_width == 0)
-      png_error(png_ptr, "internal row width error");
-
-   /* Preserve the last byte in cases where only part of it will be overwritten,
-    * the multiply below may overflow, we don't care because ANSI-C guarantees
-    * we get the low bits.
-    */
-   end_mask = (pixel_depth * row_width) & 7;
-   if (end_mask != 0)
-   {
-      /* end_ptr == NULL is a flag to say do nothing */
-      end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
-      end_byte = *end_ptr;
-#     ifdef PNG_READ_PACKSWAP_SUPPORTED
-         if (png_ptr->transformations & PNG_PACKSWAP) /* little-endian byte */
-            end_mask = 0xff << end_mask;
-
-         else /* big-endian byte */
-#     endif
-         end_mask = 0xff >> end_mask;
-      /* end_mask is now the bits to *keep* from the destination row */
-   }
-
-   /* For non-interlaced images this reduces to a png_memcpy(). A png_memcpy()
-    * will also happen if interlacing isn't supported or if the application
-    * does not call png_set_interlace_handling().  In the latter cases the
-    * caller just gets a sequence of the unexpanded rows from each interlace
-    * pass.
-    */
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE) &&
-      pass < 6 && (display == 0 ||
-      /* The following copies everything for 'display' on passes 0, 2 and 4. */
-      (display == 1 && (pass & 1) != 0)))
-   {
-      /* Narrow images may have no bits in a pass; the caller should handle
-       * this, but this test is cheap:
-       */
-      if (row_width <= PNG_PASS_START_COL(pass))
-         return;
-
-      if (pixel_depth < 8)
-      {
-         /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
-          * into 32 bits, then a single loop over the bytes using the four byte
-          * values in the 32-bit mask can be used.  For the 'display' option the
-          * expanded mask may also not require any masking within a byte.  To
-          * make this work the PACKSWAP option must be taken into account - it
-          * simply requires the pixels to be reversed in each byte.
-          *
-          * The 'regular' case requires a mask for each of the first 6 passes,
-          * the 'display' case does a copy for the even passes in the range
-          * 0..6.  This has already been handled in the test above.
-          *
-          * The masks are arranged as four bytes with the first byte to use in
-          * the lowest bits (little-endian) regardless of the order (PACKSWAP or
-          * not) of the pixels in each byte.
-          *
-          * NOTE: the whole of this logic depends on the caller of this function
-          * only calling it on rows appropriate to the pass.  This function only
-          * understands the 'x' logic; the 'y' logic is handled by the caller.
-          *
-          * The following defines allow generation of compile time constant bit
-          * masks for each pixel depth and each possibility of swapped or not
-          * swapped bytes.  Pass 'p' is in the range 0..6; 'x', a pixel index,
-          * is in the range 0..7; and the result is 1 if the pixel is to be
-          * copied in the pass, 0 if not.  'S' is for the sparkle method, 'B'
-          * for the block method.
-          *
-          * With some compilers a compile time expression of the general form:
-          *
-          *    (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
-          *
-          * Produces warnings with values of 'shift' in the range 33 to 63
-          * because the right hand side of the ?: expression is evaluated by
-          * the compiler even though it isn't used.  Microsoft Visual C (various
-          * versions) and the Intel C compiler are known to do this.  To avoid
-          * this the following macros are used in 1.5.6.  This is a temporary
-          * solution to avoid destabilizing the code during the release process.
-          */
-#        if PNG_USE_COMPILE_TIME_MASKS
-#           define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
-#           define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
-#        else
-#           define PNG_LSR(x,s) ((x)>>(s))
-#           define PNG_LSL(x,s) ((x)<<(s))
-#        endif
-#        define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
-           PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
-#        define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
-           PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
-
-         /* Return a mask for pass 'p' pixel 'x' at depth 'd'.  The mask is
-          * little endian - the first pixel is at bit 0 - however the extra
-          * parameter 's' can be set to cause the mask position to be swapped
-          * within each byte, to match the PNG format.  This is done by XOR of
-          * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
-          */
-#        define PIXEL_MASK(p,x,d,s) \
-            (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
-
-         /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
-          */
-#        define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
-#        define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
-
-         /* Combine 8 of these to get the full mask.  For the 1-bpp and 2-bpp
-          * cases the result needs replicating, for the 4-bpp case the above
-          * generates a full 32 bits.
-          */
-#        define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
-
-#        define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
-            S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
-            S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
-
-#        define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
-            B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
-            B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
-
-#if PNG_USE_COMPILE_TIME_MASKS
-         /* Utility macros to construct all the masks for a depth/swap
-          * combination.  The 's' parameter says whether the format is PNG
-          * (big endian bytes) or not.  Only the three odd-numbered passes are
-          * required for the display/block algorithm.
-          */
-#        define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
-            S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
-
-#        define B_MASKS(d,s) { B_MASK(1,d,s), S_MASK(3,d,s), S_MASK(5,d,s) }
-
-#        define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
-
-         /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
-          * then pass:
-          */
-         static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
-         {
-            /* Little-endian byte masks for PACKSWAP */
-            { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
-            /* Normal (big-endian byte) masks - PNG format */
-            { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
-         };
-
-         /* display_mask has only three entries for the odd passes, so index by
-          * pass>>1.
-          */
-         static PNG_CONST png_uint_32 display_mask[2][3][3] =
-         {
-            /* Little-endian byte masks for PACKSWAP */
-            { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
-            /* Normal (big-endian byte) masks - PNG format */
-            { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
-         };
-
-#        define MASK(pass,depth,display,png)\
-            ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
-               row_mask[png][DEPTH_INDEX(depth)][pass])
-
-#else /* !PNG_USE_COMPILE_TIME_MASKS */
-         /* This is the runtime alternative: it seems unlikely that this will
-          * ever be either smaller or faster than the compile time approach.
-          */
-#        define MASK(pass,depth,display,png)\
-            ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
-#endif /* !PNG_USE_COMPILE_TIME_MASKS */
-
-         /* Use the appropriate mask to copy the required bits.  In some cases
-          * the byte mask will be 0 or 0xff, optimize these cases.  row_width is
-          * the number of pixels, but the code copies bytes, so it is necessary
-          * to special case the end.
-          */
-         png_uint_32 pixels_per_byte = 8 / pixel_depth;
-         png_uint_32 mask;
-
-#        ifdef PNG_READ_PACKSWAP_SUPPORTED
-            if (png_ptr->transformations & PNG_PACKSWAP)
-               mask = MASK(pass, pixel_depth, display, 0);
-
-            else
-#        endif
-            mask = MASK(pass, pixel_depth, display, 1);
-
-         for (;;)
-         {
-            png_uint_32 m;
-
-            /* It doesn't matter in the following if png_uint_32 has more than
-             * 32 bits because the high bits always match those in m<<24; it is,
-             * however, essential to use OR here, not +, because of this.
-             */
-            m = mask;
-            mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
-            m &= 0xff;
-
-            if (m != 0) /* something to copy */
-            {
-               if (m != 0xff)
-                  *dp = (png_byte)((*dp & ~m) | (*sp & m));
-               else
-                  *dp = *sp;
-            }
-
-            /* NOTE: this may overwrite the last byte with garbage if the image
-             * is not an exact number of bytes wide; libpng has always done
-             * this.
-             */
-            if (row_width <= pixels_per_byte)
-               break; /* May need to restore part of the last byte */
-
-            row_width -= pixels_per_byte;
-            ++dp;
-            ++sp;
-         }
-      }
-
-      else /* pixel_depth >= 8 */
-      {
-         unsigned int bytes_to_copy, bytes_to_jump;
-
-         /* Validate the depth - it must be a multiple of 8 */
-         if (pixel_depth & 7)
-            png_error(png_ptr, "invalid user transform pixel depth");
-
-         pixel_depth >>= 3; /* now in bytes */
-         row_width *= pixel_depth;
-
-         /* Regardless of pass number the Adam 7 interlace always results in a
-          * fixed number of pixels to copy then to skip.  There may be a
-          * different number of pixels to skip at the start though.
-          */
-         {
-            unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
-
-            row_width -= offset;
-            dp += offset;
-            sp += offset;
-         }
-
-         /* Work out the bytes to copy. */
-         if (display)
-         {
-            /* When doing the 'block' algorithm the pixel in the pass gets
-             * replicated to adjacent pixels.  This is why the even (0,2,4,6)
-             * passes are skipped above - the entire expanded row is copied.
-             */
-            bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
-
-            /* But don't allow this number to exceed the actual row width. */
-            if (bytes_to_copy > row_width)
-               bytes_to_copy = row_width;
-         }
-
-         else /* normal row; Adam7 only ever gives us one pixel to copy. */
-            bytes_to_copy = pixel_depth;
-
-         /* In Adam7 there is a constant offset between where the pixels go. */
-         bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
-
-         /* And simply copy these bytes.  Some optimization is possible here,
-          * depending on the value of 'bytes_to_copy'.  Special case the low
-          * byte counts, which we know to be frequent.
-          *
-          * Notice that these cases all 'return' rather than 'break' - this
-          * avoids an unnecessary test on whether to restore the last byte
-          * below.
-          */
-         switch (bytes_to_copy)
-         {
-            case 1:
-               for (;;)
-               {
-                  *dp = *sp;
-
-                  if (row_width <= bytes_to_jump)
-                     return;
-
-                  dp += bytes_to_jump;
-                  sp += bytes_to_jump;
-                  row_width -= bytes_to_jump;
-               }
-
-            case 2:
-               /* There is a possibility of a partial copy at the end here; this
-                * slows the code down somewhat.
-                */
-               do
-               {
-                  dp[0] = sp[0], dp[1] = sp[1];
-
-                  if (row_width <= bytes_to_jump)
-                     return;
-
-                  sp += bytes_to_jump;
-                  dp += bytes_to_jump;
-                  row_width -= bytes_to_jump;
-               }
-               while (row_width > 1);
-
-               /* And there can only be one byte left at this point: */
-               *dp = *sp;
-               return;
-
-            case 3:
-               /* This can only be the RGB case, so each copy is exactly one
-                * pixel and it is not necessary to check for a partial copy.
-                */
-               for(;;)
-               {
-                  dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];
-
-                  if (row_width <= bytes_to_jump)
-                     return;
-
-                  sp += bytes_to_jump;
-                  dp += bytes_to_jump;
-                  row_width -= bytes_to_jump;
-               }
-
-            default:
-#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
-               /* Check for double byte alignment and, if possible, use a
-                * 16-bit copy.  Don't attempt this for narrow images - ones that
-                * are less than an interlace panel wide.  Don't attempt it for
-                * wide bytes_to_copy either - use the png_memcpy there.
-                */
-               if (bytes_to_copy < 16 /*else use png_memcpy*/ &&
-                  png_isaligned(dp, png_uint_16) &&
-                  png_isaligned(sp, png_uint_16) &&
-                  bytes_to_copy % sizeof (png_uint_16) == 0 &&
-                  bytes_to_jump % sizeof (png_uint_16) == 0)
-               {
-                  /* Everything is aligned for png_uint_16 copies, but try for
-                   * png_uint_32 first.
-                   */
-                  if (png_isaligned(dp, png_uint_32) &&
-                     png_isaligned(sp, png_uint_32) &&
-                     bytes_to_copy % sizeof (png_uint_32) == 0 &&
-                     bytes_to_jump % sizeof (png_uint_32) == 0)
-                  {
-                     png_uint_32p dp32 = (png_uint_32p)dp;
-                     png_const_uint_32p sp32 = (png_const_uint_32p)sp;
-                     unsigned int skip = (bytes_to_jump-bytes_to_copy) /
-                        sizeof (png_uint_32);
-
-                     do
-                     {
-                        size_t c = bytes_to_copy;
-                        do
-                        {
-                           *dp32++ = *sp32++;
-                           c -= sizeof (png_uint_32);
-                        }
-                        while (c > 0);
-
-                        if (row_width <= bytes_to_jump)
-                           return;
-
-                        dp32 += skip;
-                        sp32 += skip;
-                        row_width -= bytes_to_jump;
-                     }
-                     while (bytes_to_copy <= row_width);
-
-                     /* Get to here when the row_width truncates the final copy.
-                      * There will be 1-3 bytes left to copy, so don't try the
-                      * 16-bit loop below.
-                      */
-                     dp = (png_bytep)dp32;
-                     sp = (png_const_bytep)sp32;
-                     do
-                        *dp++ = *sp++;
-                     while (--row_width > 0);
-                     return;
-                  }
-
-                  /* Else do it in 16-bit quantities, but only if the size is
-                   * not too large.
-                   */
-                  else
-                  {
-                     png_uint_16p dp16 = (png_uint_16p)dp;
-                     png_const_uint_16p sp16 = (png_const_uint_16p)sp;
-                     unsigned int skip = (bytes_to_jump-bytes_to_copy) /
-                        sizeof (png_uint_16);
-
-                     do
-                     {
-                        size_t c = bytes_to_copy;
-                        do
-                        {
-                           *dp16++ = *sp16++;
-                           c -= sizeof (png_uint_16);
-                        }
-                        while (c > 0);
-
-                        if (row_width <= bytes_to_jump)
-                           return;
-
-                        dp16 += skip;
-                        sp16 += skip;
-                        row_width -= bytes_to_jump;
-                     }
-                     while (bytes_to_copy <= row_width);
-
-                     /* End of row - 1 byte left, bytes_to_copy > row_width: */
-                     dp = (png_bytep)dp16;
-                     sp = (png_const_bytep)sp16;
-                     do
-                        *dp++ = *sp++;
-                     while (--row_width > 0);
-                     return;
-                  }
-               }
-#endif /* PNG_ALIGN_ code */
-
-               /* The true default - use a png_memcpy: */
-               for (;;)
-               {
-                  png_memcpy(dp, sp, bytes_to_copy);
-
-                  if (row_width <= bytes_to_jump)
-                     return;
-
-                  sp += bytes_to_jump;
-                  dp += bytes_to_jump;
-                  row_width -= bytes_to_jump;
-                  if (bytes_to_copy > row_width)
-                     bytes_to_copy = row_width;
-               }
-         }
-
-         /* NOT REACHED*/
-      } /* pixel_depth >= 8 */
-
-      /* Here if pixel_depth < 8 to check 'end_ptr' below. */
-   }
-   else
-#endif
-
-   /* If here then the switch above wasn't used so just png_memcpy the whole row
-    * from the temporary row buffer (notice that this overwrites the end of the
-    * destination row if it is a partial byte.)
-    */
-   png_memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
-
-   /* Restore the overwritten bits from the last byte if necessary. */
-   if (end_ptr != NULL)
-      *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
-}
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-void /* PRIVATE */
-png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
-   png_uint_32 transformations /* Because these may affect the byte layout */)
-{
-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-   /* Offset to next interlace block */
-   static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
-   png_debug(1, "in png_do_read_interlace");
-   if (row != NULL && row_info != NULL)
-   {
-      png_uint_32 final_width;
-
-      final_width = row_info->width * png_pass_inc[pass];
-
-      switch (row_info->pixel_depth)
-      {
-         case 1:
-         {
-            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
-            png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
-            int sshift, dshift;
-            int s_start, s_end, s_inc;
-            int jstop = png_pass_inc[pass];
-            png_byte v;
-            png_uint_32 i;
-            int j;
-
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
-            if (transformations & PNG_PACKSWAP)
-            {
-                sshift = (int)((row_info->width + 7) & 0x07);
-                dshift = (int)((final_width + 7) & 0x07);
-                s_start = 7;
-                s_end = 0;
-                s_inc = -1;
-            }
-
-            else
-#endif
-            {
-                sshift = 7 - (int)((row_info->width + 7) & 0x07);
-                dshift = 7 - (int)((final_width + 7) & 0x07);
-                s_start = 0;
-                s_end = 7;
-                s_inc = 1;
-            }
-
-            for (i = 0; i < row_info->width; i++)
-            {
-               v = (png_byte)((*sp >> sshift) & 0x01);
-               for (j = 0; j < jstop; j++)
-               {
-                  *dp &= (png_byte)((0x7f7f >> (7 - dshift)) & 0xff);
-                  *dp |= (png_byte)(v << dshift);
-
-                  if (dshift == s_end)
-                  {
-                     dshift = s_start;
-                     dp--;
-                  }
-
-                  else
-                     dshift += s_inc;
-               }
-
-               if (sshift == s_end)
-               {
-                  sshift = s_start;
-                  sp--;
-               }
-
-               else
-                  sshift += s_inc;
-            }
-            break;
-         }
-
-         case 2:
-         {
-            png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
-            png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
-            int sshift, dshift;
-            int s_start, s_end, s_inc;
-            int jstop = png_pass_inc[pass];
-            png_uint_32 i;
-
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
-            if (transformations & PNG_PACKSWAP)
-            {
-               sshift = (int)(((row_info->width + 3) & 0x03) << 1);
-               dshift = (int)(((final_width + 3) & 0x03) << 1);
-               s_start = 6;
-               s_end = 0;
-               s_inc = -2;
-            }
-
-            else
-#endif
-            {
-               sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
-               dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
-               s_start = 0;
-               s_end = 6;
-               s_inc = 2;
-            }
-
-            for (i = 0; i < row_info->width; i++)
-            {
-               png_byte v;
-               int j;
-
-               v = (png_byte)((*sp >> sshift) & 0x03);
-               for (j = 0; j < jstop; j++)
-               {
-                  *dp &= (png_byte)((0x3f3f >> (6 - dshift)) & 0xff);
-                  *dp |= (png_byte)(v << dshift);
-
-                  if (dshift == s_end)
-                  {
-                     dshift = s_start;
-                     dp--;
-                  }
-
-                  else
-                     dshift += s_inc;
-               }
-
-               if (sshift == s_end)
-               {
-                  sshift = s_start;
-                  sp--;
-               }
-
-               else
-                  sshift += s_inc;
-            }
-            break;
-         }
-
-         case 4:
-         {
-            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
-            png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
-            int sshift, dshift;
-            int s_start, s_end, s_inc;
-            png_uint_32 i;
-            int jstop = png_pass_inc[pass];
-
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
-            if (transformations & PNG_PACKSWAP)
-            {
-               sshift = (int)(((row_info->width + 1) & 0x01) << 2);
-               dshift = (int)(((final_width + 1) & 0x01) << 2);
-               s_start = 4;
-               s_end = 0;
-               s_inc = -4;
-            }
-
-            else
-#endif
-            {
-               sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
-               dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
-               s_start = 0;
-               s_end = 4;
-               s_inc = 4;
-            }
-
-            for (i = 0; i < row_info->width; i++)
-            {
-               png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
-               int j;
-
-               for (j = 0; j < jstop; j++)
-               {
-                  *dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff);
-                  *dp |= (png_byte)(v << dshift);
-
-                  if (dshift == s_end)
-                  {
-                     dshift = s_start;
-                     dp--;
-                  }
-
-                  else
-                     dshift += s_inc;
-               }
-
-               if (sshift == s_end)
-               {
-                  sshift = s_start;
-                  sp--;
-               }
-
-               else
-                  sshift += s_inc;
-            }
-            break;
-         }
-
-         default:
-         {
-            png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
-
-            png_bytep sp = row + (png_size_t)(row_info->width - 1)
-                * pixel_bytes;
-
-            png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
-
-            int jstop = png_pass_inc[pass];
-            png_uint_32 i;
-
-            for (i = 0; i < row_info->width; i++)
-            {
-               png_byte v[8];
-               int j;
-
-               png_memcpy(v, sp, pixel_bytes);
-
-               for (j = 0; j < jstop; j++)
-               {
-                  png_memcpy(dp, v, pixel_bytes);
-                  dp -= pixel_bytes;
-               }
-
-               sp -= pixel_bytes;
-            }
-            break;
-         }
-      }
-
-      row_info->width = final_width;
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
-   }
-#ifndef PNG_READ_PACKSWAP_SUPPORTED
-   PNG_UNUSED(transformations)  /* Silence compiler warning */
-#endif
-}
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-
-static void
-png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
-   png_const_bytep prev_row)
-{
-   png_size_t i;
-   png_size_t istop = row_info->rowbytes;
-   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
-   png_bytep rp = row + bpp;
-
-   PNG_UNUSED(prev_row)
-
-   for (i = bpp; i < istop; i++)
-   {
-      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
-      rp++;
-   }
-}
-
-static void
-png_read_filter_row_up(png_row_infop row_info, png_bytep row,
-   png_const_bytep prev_row)
-{
-   png_size_t i;
-   png_size_t istop = row_info->rowbytes;
-   png_bytep rp = row;
-   png_const_bytep pp = prev_row;
-
-   for (i = 0; i < istop; i++)
-   {
-      *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
-      rp++;
-   }
-}
-
-static void
-png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
-   png_const_bytep prev_row)
-{
-   png_size_t i;
-   png_bytep rp = row;
-   png_const_bytep pp = prev_row;
-   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
-   png_size_t istop = row_info->rowbytes - bpp;
-
-   for (i = 0; i < bpp; i++)
-   {
-      *rp = (png_byte)(((int)(*rp) +
-         ((int)(*pp++) / 2 )) & 0xff);
-
-      rp++;
-   }
-
-   for (i = 0; i < istop; i++)
-   {
-      *rp = (png_byte)(((int)(*rp) +
-         (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
-
-      rp++;
-   }
-}
-
-static void
-png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
-   png_const_bytep prev_row)
-{
-   png_bytep rp_end = row + row_info->rowbytes;
-   int a, c;
-
-   /* First pixel/byte */
-   c = *prev_row++;
-   a = *row + c;
-   *row++ = (png_byte)a;
-
-   /* Remainder */
-   while (row < rp_end)
-   {
-      int b, pa, pb, pc, p;
-
-      a &= 0xff; /* From previous iteration or start */
-      b = *prev_row++;
-
-      p = b - c;
-      pc = a - c;
-
-#     ifdef PNG_USE_ABS
-         pa = abs(p);
-         pb = abs(pc);
-         pc = abs(p + pc);
-#     else
-         pa = p < 0 ? -p : p;
-         pb = pc < 0 ? -pc : pc;
-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#     endif
-
-      /* Find the best predictor, the least of pa, pb, pc favoring the earlier
-       * ones in the case of a tie.
-       */
-      if (pb < pa) pa = pb, a = b;
-      if (pc < pa) a = c;
-
-      /* Calculate the current pixel in a, and move the previous row pixel to c
-       * for the next time round the loop
-       */
-      c = b;
-      a += *row;
-      *row++ = (png_byte)a;
-   }
-}
-
-static void
-png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
-   png_const_bytep prev_row)
-{
-   int bpp = (row_info->pixel_depth + 7) >> 3;
-   png_bytep rp_end = row + bpp;
-
-   /* Process the first pixel in the row completely (this is the same as 'up'
-    * because there is only one candidate predictor for the first row).
-    */
-   while (row < rp_end)
-   {
-      int a = *row + *prev_row++;
-      *row++ = (png_byte)a;
-   }
-
-   /* Remainder */
-   rp_end += row_info->rowbytes - bpp;
-
-   while (row < rp_end)
-   {
-      int a, b, c, pa, pb, pc, p;
-
-      c = *(prev_row - bpp);
-      a = *(row - bpp);
-      b = *prev_row++;
-
-      p = b - c;
-      pc = a - c;
-
-#     ifdef PNG_USE_ABS
-         pa = abs(p);
-         pb = abs(pc);
-         pc = abs(p + pc);
-#     else
-         pa = p < 0 ? -p : p;
-         pb = pc < 0 ? -pc : pc;
-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#     endif
-
-      if (pb < pa) pa = pb, a = b;
-      if (pc < pa) a = c;
-
-      c = b;
-      a += *row;
-      *row++ = (png_byte)a;
-   }
-}
-
-#ifdef PNG_ARM_NEON
-
-#ifdef __linux__
-#include <stdio.h>
-#include <elf.h>
-#include <asm/hwcap.h>
-
-static int png_have_hwcap(unsigned cap)
-{
-   FILE *f = fopen("/proc/self/auxv", "r");
-   Elf32_auxv_t aux;
-   int have_cap = 0;
-
-   if (!f)
-      return 0;
-
-   while (fread(&aux, sizeof(aux), 1, f) > 0)
-   {
-      if (aux.a_type == AT_HWCAP &&
-          aux.a_un.a_val & cap)
-      {
-         have_cap = 1;
-         break;
-      }
-   }
-
-   fclose(f);
-
-   return have_cap;
-}
-#endif /* __linux__ */
-
-static void
-png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
-{
-#ifdef __linux__
-   if (!png_have_hwcap(HWCAP_NEON))
-      return;
-#endif
-
-   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
-
-   if (bpp == 3)
-   {
-      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
-      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
-      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 
-         png_read_filter_row_paeth3_neon;
-   }
-
-   else if (bpp == 4)
-   {
-      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
-      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
-      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
-          png_read_filter_row_paeth4_neon;
-   }
-}
-#endif /* PNG_ARM_NEON */
-
-static void
-png_init_filter_functions(png_structp pp)
-{
-   unsigned int bpp = (pp->pixel_depth + 7) >> 3;
-
-   pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
-   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
-   pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
-   if (bpp == 1)
-      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
-         png_read_filter_row_paeth_1byte_pixel;
-   else
-      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
-         png_read_filter_row_paeth_multibyte_pixel;
-
-#ifdef PNG_ARM_NEON
-   png_init_filter_functions_neon(pp, bpp);
-#endif
-}
-
-void /* PRIVATE */
-png_read_filter_row(png_structp pp, png_row_infop row_info, png_bytep row,
-   png_const_bytep prev_row, int filter)
-{
-   if (pp->read_filter[0] == NULL)
-      png_init_filter_functions(pp);
-   if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
-      pp->read_filter[filter-1](row_info, row, prev_row);
-}
-
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-void /* PRIVATE */
-png_read_finish_row(png_structp png_ptr)
-{
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
-   /* Start of interlace block */
-   static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
-   /* Offset to next interlace block */
-   static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
-   /* Start of interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
-   /* Offset to next interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-
-   png_debug(1, "in png_read_finish_row");
-   png_ptr->row_number++;
-   if (png_ptr->row_number < png_ptr->num_rows)
-      return;
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   if (png_ptr->interlaced)
-   {
-      png_ptr->row_number = 0;
-
-      /* TO DO: don't do this if prev_row isn't needed (requires
-       * read-ahead of the next row's filter byte.
-       */
-      png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
-
-      do
-      {
-         png_ptr->pass++;
-
-         if (png_ptr->pass >= 7)
-            break;
-
-         png_ptr->iwidth = (png_ptr->width +
-            png_pass_inc[png_ptr->pass] - 1 -
-            png_pass_start[png_ptr->pass]) /
-            png_pass_inc[png_ptr->pass];
-
-         if (!(png_ptr->transformations & PNG_INTERLACE))
-         {
-            png_ptr->num_rows = (png_ptr->height +
-                png_pass_yinc[png_ptr->pass] - 1 -
-                png_pass_ystart[png_ptr->pass]) /
-                png_pass_yinc[png_ptr->pass];
-         }
-
-         else  /* if (png_ptr->transformations & PNG_INTERLACE) */
-            break; /* libpng deinterlacing sees every row */
-
-      } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
-
-      if (png_ptr->pass < 7)
-         return;
-   }
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-
-   if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
-   {
-      char extra;
-      int ret;
-
-      png_ptr->zstream.next_out = (Byte *)&extra;
-      png_ptr->zstream.avail_out = (uInt)1;
-
-      for (;;)
-      {
-         if (!(png_ptr->zstream.avail_in))
-         {
-            while (!png_ptr->idat_size)
-            {
-               png_crc_finish(png_ptr, 0);
-               png_ptr->idat_size = png_read_chunk_header(png_ptr);
-               if (png_ptr->chunk_name != png_IDAT)
-                  png_error(png_ptr, "Not enough image data");
-            }
-
-            png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
-            png_ptr->zstream.next_in = png_ptr->zbuf;
-
-            if (png_ptr->zbuf_size > png_ptr->idat_size)
-               png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
-
-            png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zstream.avail_in);
-            png_ptr->idat_size -= png_ptr->zstream.avail_in;
-         }
-
-         ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
-
-         if (ret == Z_STREAM_END)
-         {
-            if (!(png_ptr->zstream.avail_out) || png_ptr->zstream.avail_in ||
-                png_ptr->idat_size)
-               png_warning(png_ptr, "Extra compressed data");
-
-            png_ptr->mode |= PNG_AFTER_IDAT;
-            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
-            break;
-         }
-
-         if (ret != Z_OK)
-            png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
-                "Decompression Error");
-
-         if (!(png_ptr->zstream.avail_out))
-         {
-            png_warning(png_ptr, "Extra compressed data");
-            png_ptr->mode |= PNG_AFTER_IDAT;
-            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
-            break;
-         }
-
-      }
-      png_ptr->zstream.avail_out = 0;
-   }
-
-   if (png_ptr->idat_size || png_ptr->zstream.avail_in)
-      png_warning(png_ptr, "Extra compression data");
-
-   inflateReset(&png_ptr->zstream);
-
-   png_ptr->mode |= PNG_AFTER_IDAT;
-}
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
-
-void /* PRIVATE */
-png_read_start_row(png_structp png_ptr)
-{
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
-   /* Start of interlace block */
-   static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
-   /* Offset to next interlace block */
-   static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
-   /* Start of interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
-   /* Offset to next interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif
-
-   int max_pixel_depth;
-   png_size_t row_bytes;
-
-   png_debug(1, "in png_read_start_row");
-   png_ptr->zstream.avail_in = 0;
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-   png_init_read_transformations(png_ptr);
-#endif
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   if (png_ptr->interlaced)
-   {
-      if (!(png_ptr->transformations & PNG_INTERLACE))
-         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
-             png_pass_ystart[0]) / png_pass_yinc[0];
-
-      else
-         png_ptr->num_rows = png_ptr->height;
-
-      png_ptr->iwidth = (png_ptr->width +
-          png_pass_inc[png_ptr->pass] - 1 -
-          png_pass_start[png_ptr->pass]) /
-          png_pass_inc[png_ptr->pass];
-   }
-
-   else
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-   {
-      png_ptr->num_rows = png_ptr->height;
-      png_ptr->iwidth = png_ptr->width;
-   }
-
-   max_pixel_depth = png_ptr->pixel_depth;
-
-   /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of
-    * calculations to calculate the final pixel depth, then
-    * png_do_read_transforms actually does the transforms.  This means that the
-    * code which effectively calculates this value is actually repeated in three
-    * separate places.  They must all match.  Innocent changes to the order of
-    * transformations can and will break libpng in a way that causes memory
-    * overwrites.
-    *
-    * TODO: fix this.
-    */
-#ifdef PNG_READ_PACK_SUPPORTED
-   if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
-      max_pixel_depth = 8;
-#endif
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND)
-   {
-      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         if (png_ptr->num_trans)
-            max_pixel_depth = 32;
-
-         else
-            max_pixel_depth = 24;
-      }
-
-      else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
-      {
-         if (max_pixel_depth < 8)
-            max_pixel_depth = 8;
-
-         if (png_ptr->num_trans)
-            max_pixel_depth *= 2;
-      }
-
-      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
-      {
-         if (png_ptr->num_trans)
-         {
-            max_pixel_depth *= 4;
-            max_pixel_depth /= 3;
-         }
-      }
-   }
-#endif
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND_16)
-   {
-#     ifdef PNG_READ_EXPAND_SUPPORTED
-         /* In fact it is an error if it isn't supported, but checking is
-          * the safe way.
-          */
-         if (png_ptr->transformations & PNG_EXPAND)
-         {
-            if (png_ptr->bit_depth < 16)
-               max_pixel_depth *= 2;
-         }
-         else
-#     endif
-         png_ptr->transformations &= ~PNG_EXPAND_16;
-   }
-#endif
-
-#ifdef PNG_READ_FILLER_SUPPORTED
-   if (png_ptr->transformations & (PNG_FILLER))
-   {
-      if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
-      {
-         if (max_pixel_depth <= 8)
-            max_pixel_depth = 16;
-
-         else
-            max_pixel_depth = 32;
-      }
-
-      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
-         png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         if (max_pixel_depth <= 32)
-            max_pixel_depth = 32;
-
-         else
-            max_pixel_depth = 64;
-      }
-   }
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-   if (png_ptr->transformations & PNG_GRAY_TO_RGB)
-   {
-      if (
-#ifdef PNG_READ_EXPAND_SUPPORTED
-          (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) ||
-#endif
-#ifdef PNG_READ_FILLER_SUPPORTED
-          (png_ptr->transformations & (PNG_FILLER)) ||
-#endif
-          png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      {
-         if (max_pixel_depth <= 16)
-            max_pixel_depth = 32;
-
-         else
-            max_pixel_depth = 64;
-      }
-
-      else
-      {
-         if (max_pixel_depth <= 8)
-         {
-            if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-               max_pixel_depth = 32;
-
-            else
-               max_pixel_depth = 24;
-         }
-
-         else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            max_pixel_depth = 64;
-
-         else
-            max_pixel_depth = 48;
-      }
-   }
-#endif
-
-#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
-defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
-   {
-      int user_pixel_depth = png_ptr->user_transform_depth *
-         png_ptr->user_transform_channels;
-
-      if (user_pixel_depth > max_pixel_depth)
-         max_pixel_depth = user_pixel_depth;
-   }
-#endif
-
-   /* This value is stored in png_struct and double checked in the row read
-    * code.
-    */
-   png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
-   png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
-
-   /* Align the width on the next larger 8 pixels.  Mainly used
-    * for interlacing
-    */
-   row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
-   /* Calculate the maximum bytes needed, adding a byte and a pixel
-    * for safety's sake
-    */
-   row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
-       1 + ((max_pixel_depth + 7) >> 3);
-
-#ifdef PNG_MAX_MALLOC_64K
-   if (row_bytes > (png_uint_32)65536L)
-      png_error(png_ptr, "This image requires a row greater than 64KB");
-#endif
-
-   if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
-   {
-     png_free(png_ptr, png_ptr->big_row_buf);
-     png_free(png_ptr, png_ptr->big_prev_row);
-
-     if (png_ptr->interlaced)
-        png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
-            row_bytes + 48);
-
-     else
-        png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
-
-     png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
-
-#ifdef PNG_ALIGNED_MEMORY_SUPPORTED
-     /* Use 16-byte aligned memory for row_buf with at least 16 bytes
-      * of padding before and after row_buf; treat prev_row similarly.
-      * NOTE: the alignment is to the start of the pixels, one beyond the start
-      * of the buffer, because of the filter byte.  Prior to libpng 1.5.6 this
-      * was incorrect; the filter byte was aligned, which had the exact
-      * opposite effect of that intended.
-      */
-     {
-        png_bytep temp = png_ptr->big_row_buf + 32;
-        int extra = (int)((temp - (png_bytep)0) & 0x0f);
-        png_ptr->row_buf = temp - extra - 1/*filter byte*/;
-
-        temp = png_ptr->big_prev_row + 32;
-        extra = (int)((temp - (png_bytep)0) & 0x0f);
-        png_ptr->prev_row = temp - extra - 1/*filter byte*/;
-     }
-
-#else
-     /* Use 31 bytes of padding before and 17 bytes after row_buf. */
-     png_ptr->row_buf = png_ptr->big_row_buf + 31;
-     png_ptr->prev_row = png_ptr->big_prev_row + 31;
-#endif
-     png_ptr->old_big_row_buf_size = row_bytes + 48;
-   }
-
-#ifdef PNG_MAX_MALLOC_64K
-   if (png_ptr->rowbytes > 65535)
-      png_error(png_ptr, "This image requires a row greater than 64KB");
-
-#endif
-   if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
-      png_error(png_ptr, "Row has too many bytes to allocate in memory");
-
-   png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
-
-   png_debug1(3, "width = %u,", png_ptr->width);
-   png_debug1(3, "height = %u,", png_ptr->height);
-   png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
-   png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
-   png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
-   png_debug1(3, "irowbytes = %lu",
-       (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
-
-   png_ptr->flags |= PNG_FLAG_ROW_INIT;
-}
-#endif /* PNG_READ_SUPPORTED */
diff --git a/extern/libpng/include/pngset.c b/extern/libpng/include/pngset.c
deleted file mode 100644
index e0118fa8c2..0000000000
--- a/extern/libpng/include/pngset.c
+++ /dev/null
@@ -1,1309 +0,0 @@
-
-/* pngset.c - storage of image information into info struct
- *
- * Last changed in libpng 1.5.10 [(PENDING RELEASE)]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * The functions here are used during reads to store data from the file
- * into the info struct, and during writes to store application data
- * into the info struct for writing into the file.  This abstracts the
- * info struct and allows us to change the structure in the future.
- */
-
-#include "pngpriv.h"
-
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-
-#ifdef PNG_bKGD_SUPPORTED
-void PNGAPI
-png_set_bKGD(png_structp png_ptr, png_infop info_ptr,
-    png_const_color_16p background)
-{
-   png_debug1(1, "in %s storage function", "bKGD");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   png_memcpy(&(info_ptr->background), background, png_sizeof(png_color_16));
-   info_ptr->valid |= PNG_INFO_bKGD;
-}
-#endif
-
-#ifdef PNG_cHRM_SUPPORTED
-void PNGFAPI
-png_set_cHRM_fixed(png_structp png_ptr, png_infop info_ptr,
-    png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
-    png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
-    png_fixed_point blue_x, png_fixed_point blue_y)
-{
-   png_debug1(1, "in %s storage function", "cHRM fixed");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-#  ifdef PNG_CHECK_cHRM_SUPPORTED
-   if (png_check_cHRM_fixed(png_ptr,
-       white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y))
-#  endif
-   {
-      info_ptr->x_white = white_x;
-      info_ptr->y_white = white_y;
-      info_ptr->x_red   = red_x;
-      info_ptr->y_red   = red_y;
-      info_ptr->x_green = green_x;
-      info_ptr->y_green = green_y;
-      info_ptr->x_blue  = blue_x;
-      info_ptr->y_blue  = blue_y;
-      info_ptr->valid |= PNG_INFO_cHRM;
-   }
-}
-
-void PNGFAPI
-png_set_cHRM_XYZ_fixed(png_structp png_ptr, png_infop info_ptr,
-    png_fixed_point int_red_X, png_fixed_point int_red_Y,
-    png_fixed_point int_red_Z, png_fixed_point int_green_X,
-    png_fixed_point int_green_Y, png_fixed_point int_green_Z,
-    png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
-    png_fixed_point int_blue_Z)
-{
-   png_XYZ XYZ;
-   png_xy xy;
-
-   png_debug1(1, "in %s storage function", "cHRM XYZ fixed");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   XYZ.redX = int_red_X;
-   XYZ.redY = int_red_Y;
-   XYZ.redZ = int_red_Z;
-   XYZ.greenX = int_green_X;
-   XYZ.greenY = int_green_Y;
-   XYZ.greenZ = int_green_Z;
-   XYZ.blueX = int_blue_X;
-   XYZ.blueY = int_blue_Y;
-   XYZ.blueZ = int_blue_Z;
-
-   if (png_xy_from_XYZ(&xy, XYZ))
-      png_error(png_ptr, "XYZ values out of representable range");
-
-   png_set_cHRM_fixed(png_ptr, info_ptr, xy.whitex, xy.whitey, xy.redx, xy.redy,
-      xy.greenx, xy.greeny, xy.bluex, xy.bluey);
-}
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_cHRM(png_structp png_ptr, png_infop info_ptr,
-    double white_x, double white_y, double red_x, double red_y,
-    double green_x, double green_y, double blue_x, double blue_y)
-{
-   png_set_cHRM_fixed(png_ptr, info_ptr,
-      png_fixed(png_ptr, white_x, "cHRM White X"),
-      png_fixed(png_ptr, white_y, "cHRM White Y"),
-      png_fixed(png_ptr, red_x, "cHRM Red X"),
-      png_fixed(png_ptr, red_y, "cHRM Red Y"),
-      png_fixed(png_ptr, green_x, "cHRM Green X"),
-      png_fixed(png_ptr, green_y, "cHRM Green Y"),
-      png_fixed(png_ptr, blue_x, "cHRM Blue X"),
-      png_fixed(png_ptr, blue_y, "cHRM Blue Y"));
-}
-
-void PNGAPI
-png_set_cHRM_XYZ(png_structp png_ptr, png_infop info_ptr, double red_X,
-    double red_Y, double red_Z, double green_X, double green_Y, double green_Z,
-    double blue_X, double blue_Y, double blue_Z)
-{
-   png_set_cHRM_XYZ_fixed(png_ptr, info_ptr,
-      png_fixed(png_ptr, red_X, "cHRM Red X"),
-      png_fixed(png_ptr, red_Y, "cHRM Red Y"),
-      png_fixed(png_ptr, red_Z, "cHRM Red Z"),
-      png_fixed(png_ptr, green_X, "cHRM Red X"),
-      png_fixed(png_ptr, green_Y, "cHRM Red Y"),
-      png_fixed(png_ptr, green_Z, "cHRM Red Z"),
-      png_fixed(png_ptr, blue_X, "cHRM Red X"),
-      png_fixed(png_ptr, blue_Y, "cHRM Red Y"),
-      png_fixed(png_ptr, blue_Z, "cHRM Red Z"));
-}
-#  endif /* PNG_FLOATING_POINT_SUPPORTED */
-
-#endif /* PNG_cHRM_SUPPORTED */
-
-#ifdef PNG_gAMA_SUPPORTED
-void PNGFAPI
-png_set_gAMA_fixed(png_structp png_ptr, png_infop info_ptr, png_fixed_point
-    file_gamma)
-{
-   png_debug1(1, "in %s storage function", "gAMA");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
-    * occur.  Since the fixed point representation is assymetrical it is
-    * possible for 1/gamma to overflow the limit of 21474 and this means the
-    * gamma value must be at least 5/100000 and hence at most 20000.0.  For
-    * safety the limits here are a little narrower.  The values are 0.00016 to
-    * 6250.0, which are truly ridiculous gammma values (and will produce
-    * displays that are all black or all white.)
-    */
-   if (file_gamma < 16 || file_gamma > 625000000)
-      png_warning(png_ptr, "Out of range gamma value ignored");
-
-   else
-   {
-      info_ptr->gamma = file_gamma;
-      info_ptr->valid |= PNG_INFO_gAMA;
-   }
-}
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_gAMA(png_structp png_ptr, png_infop info_ptr, double file_gamma)
-{
-   png_set_gAMA_fixed(png_ptr, info_ptr, png_fixed(png_ptr, file_gamma,
-       "png_set_gAMA"));
-}
-#  endif
-#endif
-
-#ifdef PNG_hIST_SUPPORTED
-void PNGAPI
-png_set_hIST(png_structp png_ptr, png_infop info_ptr, png_const_uint_16p hist)
-{
-   int i;
-
-   png_debug1(1, "in %s storage function", "hIST");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   if (info_ptr->num_palette == 0 || info_ptr->num_palette
-       > PNG_MAX_PALETTE_LENGTH)
-   {
-      png_warning(png_ptr,
-          "Invalid palette size, hIST allocation skipped");
-
-      return;
-   }
-
-   png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0);
-
-   /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in
-    * version 1.2.1
-    */
-   png_ptr->hist = (png_uint_16p)png_malloc_warn(png_ptr,
-       PNG_MAX_PALETTE_LENGTH * png_sizeof(png_uint_16));
-
-   if (png_ptr->hist == NULL)
-   {
-      png_warning(png_ptr, "Insufficient memory for hIST chunk data");
-      return;
-   }
-
-   for (i = 0; i < info_ptr->num_palette; i++)
-      png_ptr->hist[i] = hist[i];
-
-   info_ptr->hist = png_ptr->hist;
-   info_ptr->valid |= PNG_INFO_hIST;
-   info_ptr->free_me |= PNG_FREE_HIST;
-}
-#endif
-
-void PNGAPI
-png_set_IHDR(png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 width, png_uint_32 height, int bit_depth,
-    int color_type, int interlace_type, int compression_type,
-    int filter_type)
-{
-   png_debug1(1, "in %s storage function", "IHDR");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   info_ptr->width = width;
-   info_ptr->height = height;
-   info_ptr->bit_depth = (png_byte)bit_depth;
-   info_ptr->color_type = (png_byte)color_type;
-   info_ptr->compression_type = (png_byte)compression_type;
-   info_ptr->filter_type = (png_byte)filter_type;
-   info_ptr->interlace_type = (png_byte)interlace_type;
-
-   png_check_IHDR (png_ptr, info_ptr->width, info_ptr->height,
-       info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
-       info_ptr->compression_type, info_ptr->filter_type);
-
-   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      info_ptr->channels = 1;
-
-   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
-      info_ptr->channels = 3;
-
-   else
-      info_ptr->channels = 1;
-
-   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
-      info_ptr->channels++;
-
-   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
-
-   /* Check for potential overflow */
-   if (width >
-       (PNG_UINT_32_MAX >> 3)      /* 8-byte RRGGBBAA pixels */
-       - 48       /* bigrowbuf hack */
-       - 1        /* filter byte */
-       - 7*8      /* rounding of width to multiple of 8 pixels */
-       - 8)       /* extra max_pixel_depth pad */
-      info_ptr->rowbytes = 0;
-   else
-      info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
-}
-
-#ifdef PNG_oFFs_SUPPORTED
-void PNGAPI
-png_set_oFFs(png_structp png_ptr, png_infop info_ptr,
-    png_int_32 offset_x, png_int_32 offset_y, int unit_type)
-{
-   png_debug1(1, "in %s storage function", "oFFs");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   info_ptr->x_offset = offset_x;
-   info_ptr->y_offset = offset_y;
-   info_ptr->offset_unit_type = (png_byte)unit_type;
-   info_ptr->valid |= PNG_INFO_oFFs;
-}
-#endif
-
-#ifdef PNG_pCAL_SUPPORTED
-void PNGAPI
-png_set_pCAL(png_structp png_ptr, png_infop info_ptr,
-    png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type,
-    int nparams, png_const_charp units, png_charpp params)
-{
-   png_size_t length;
-   int i;
-
-   png_debug1(1, "in %s storage function", "pCAL");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   length = png_strlen(purpose) + 1;
-   png_debug1(3, "allocating purpose for info (%lu bytes)",
-       (unsigned long)length);
-
-   /* TODO: validate format of calibration name and unit name */
-
-   /* Check that the type matches the specification. */
-   if (type < 0 || type > 3)
-      png_error(png_ptr, "Invalid pCAL equation type");
-
-   /* Validate params[nparams] */
-   for (i=0; i<nparams; ++i)
-      if (!png_check_fp_string(params[i], png_strlen(params[i])))
-         png_error(png_ptr, "Invalid format for pCAL parameter");
-
-   info_ptr->pcal_purpose = (png_charp)png_malloc_warn(png_ptr, length);
-
-   if (info_ptr->pcal_purpose == NULL)
-   {
-      png_warning(png_ptr, "Insufficient memory for pCAL purpose");
-      return;
-   }
-
-   png_memcpy(info_ptr->pcal_purpose, purpose, length);
-
-   png_debug(3, "storing X0, X1, type, and nparams in info");
-   info_ptr->pcal_X0 = X0;
-   info_ptr->pcal_X1 = X1;
-   info_ptr->pcal_type = (png_byte)type;
-   info_ptr->pcal_nparams = (png_byte)nparams;
-
-   length = png_strlen(units) + 1;
-   png_debug1(3, "allocating units for info (%lu bytes)",
-     (unsigned long)length);
-
-   info_ptr->pcal_units = (png_charp)png_malloc_warn(png_ptr, length);
-
-   if (info_ptr->pcal_units == NULL)
-   {
-      png_warning(png_ptr, "Insufficient memory for pCAL units");
-      return;
-   }
-
-   png_memcpy(info_ptr->pcal_units, units, length);
-
-   info_ptr->pcal_params = (png_charpp)png_malloc_warn(png_ptr,
-       (png_size_t)((nparams + 1) * png_sizeof(png_charp)));
-
-   if (info_ptr->pcal_params == NULL)
-   {
-      png_warning(png_ptr, "Insufficient memory for pCAL params");
-      return;
-   }
-
-   png_memset(info_ptr->pcal_params, 0, (nparams + 1) * png_sizeof(png_charp));
-
-   for (i = 0; i < nparams; i++)
-   {
-      length = png_strlen(params[i]) + 1;
-      png_debug2(3, "allocating parameter %d for info (%lu bytes)", i,
-          (unsigned long)length);
-
-      info_ptr->pcal_params[i] = (png_charp)png_malloc_warn(png_ptr, length);
-
-      if (info_ptr->pcal_params[i] == NULL)
-      {
-         png_warning(png_ptr, "Insufficient memory for pCAL parameter");
-         return;
-      }
-
-      png_memcpy(info_ptr->pcal_params[i], params[i], length);
-   }
-
-   info_ptr->valid |= PNG_INFO_pCAL;
-   info_ptr->free_me |= PNG_FREE_PCAL;
-}
-#endif
-
-#ifdef PNG_sCAL_SUPPORTED
-void PNGAPI
-png_set_sCAL_s(png_structp png_ptr, png_infop info_ptr,
-    int unit, png_const_charp swidth, png_const_charp sheight)
-{
-   png_size_t lengthw = 0, lengthh = 0;
-
-   png_debug1(1, "in %s storage function", "sCAL");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   /* Double check the unit (should never get here with an invalid
-    * unit unless this is an API call.)
-    */
-   if (unit != 1 && unit != 2)
-      png_error(png_ptr, "Invalid sCAL unit");
-
-   if (swidth == NULL || (lengthw = png_strlen(swidth)) == 0 ||
-       swidth[0] == 45 /* '-' */ || !png_check_fp_string(swidth, lengthw))
-      png_error(png_ptr, "Invalid sCAL width");
-
-   if (sheight == NULL || (lengthh = png_strlen(sheight)) == 0 ||
-       sheight[0] == 45 /* '-' */ || !png_check_fp_string(sheight, lengthh))
-      png_error(png_ptr, "Invalid sCAL height");
-
-   info_ptr->scal_unit = (png_byte)unit;
-
-   ++lengthw;
-
-   png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthw);
-
-   info_ptr->scal_s_width = (png_charp)png_malloc_warn(png_ptr, lengthw);
-
-   if (info_ptr->scal_s_width == NULL)
-   {
-      png_warning(png_ptr, "Memory allocation failed while processing sCAL");
-      return;
-   }
-
-   png_memcpy(info_ptr->scal_s_width, swidth, lengthw);
-
-   ++lengthh;
-
-   png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthh);
-
-   info_ptr->scal_s_height = (png_charp)png_malloc_warn(png_ptr, lengthh);
-
-   if (info_ptr->scal_s_height == NULL)
-   {
-      png_free (png_ptr, info_ptr->scal_s_width);
-      info_ptr->scal_s_width = NULL;
-
-      png_warning(png_ptr, "Memory allocation failed while processing sCAL");
-      return;
-   }
-
-   png_memcpy(info_ptr->scal_s_height, sheight, lengthh);
-
-   info_ptr->valid |= PNG_INFO_sCAL;
-   info_ptr->free_me |= PNG_FREE_SCAL;
-}
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_sCAL(png_structp png_ptr, png_infop info_ptr, int unit, double width,
-    double height)
-{
-   png_debug1(1, "in %s storage function", "sCAL");
-
-   /* Check the arguments. */
-   if (width <= 0)
-      png_warning(png_ptr, "Invalid sCAL width ignored");
-
-   else if (height <= 0)
-      png_warning(png_ptr, "Invalid sCAL height ignored");
-
-   else
-   {
-      /* Convert 'width' and 'height' to ASCII. */
-      char swidth[PNG_sCAL_MAX_DIGITS+1];
-      char sheight[PNG_sCAL_MAX_DIGITS+1];
-
-      png_ascii_from_fp(png_ptr, swidth, sizeof swidth, width,
-         PNG_sCAL_PRECISION);
-      png_ascii_from_fp(png_ptr, sheight, sizeof sheight, height,
-         PNG_sCAL_PRECISION);
-
-      png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
-   }
-}
-#  endif
-
-#  ifdef PNG_FIXED_POINT_SUPPORTED
-void PNGAPI
-png_set_sCAL_fixed(png_structp png_ptr, png_infop info_ptr, int unit,
-    png_fixed_point width, png_fixed_point height)
-{
-   png_debug1(1, "in %s storage function", "sCAL");
-
-   /* Check the arguments. */
-   if (width <= 0)
-      png_warning(png_ptr, "Invalid sCAL width ignored");
-
-   else if (height <= 0)
-      png_warning(png_ptr, "Invalid sCAL height ignored");
-
-   else
-   {
-      /* Convert 'width' and 'height' to ASCII. */
-      char swidth[PNG_sCAL_MAX_DIGITS+1];
-      char sheight[PNG_sCAL_MAX_DIGITS+1];
-
-      png_ascii_from_fixed(png_ptr, swidth, sizeof swidth, width);
-      png_ascii_from_fixed(png_ptr, sheight, sizeof sheight, height);
-
-      png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
-   }
-}
-#  endif
-#endif
-
-#ifdef PNG_pHYs_SUPPORTED
-void PNGAPI
-png_set_pHYs(png_structp png_ptr, png_infop info_ptr,
-    png_uint_32 res_x, png_uint_32 res_y, int unit_type)
-{
-   png_debug1(1, "in %s storage function", "pHYs");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   info_ptr->x_pixels_per_unit = res_x;
-   info_ptr->y_pixels_per_unit = res_y;
-   info_ptr->phys_unit_type = (png_byte)unit_type;
-   info_ptr->valid |= PNG_INFO_pHYs;
-}
-#endif
-
-void PNGAPI
-png_set_PLTE(png_structp png_ptr, png_infop info_ptr,
-    png_const_colorp palette, int num_palette)
-{
-
-   png_debug1(1, "in %s storage function", "PLTE");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   if (num_palette < 0 || num_palette > PNG_MAX_PALETTE_LENGTH)
-   {
-      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-         png_error(png_ptr, "Invalid palette length");
-
-      else
-      {
-         png_warning(png_ptr, "Invalid palette length");
-         return;
-      }
-   }
-
-   /* It may not actually be necessary to set png_ptr->palette here;
-    * we do it for backward compatibility with the way the png_handle_tRNS
-    * function used to do the allocation.
-    */
-   png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0);
-
-   /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
-    * of num_palette entries, in case of an invalid PNG file that has
-    * too-large sample values.
-    */
-   png_ptr->palette = (png_colorp)png_calloc(png_ptr,
-       PNG_MAX_PALETTE_LENGTH * png_sizeof(png_color));
-
-   png_memcpy(png_ptr->palette, palette, num_palette * png_sizeof(png_color));
-   info_ptr->palette = png_ptr->palette;
-   info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;
-
-   info_ptr->free_me |= PNG_FREE_PLTE;
-
-   info_ptr->valid |= PNG_INFO_PLTE;
-}
-
-#ifdef PNG_sBIT_SUPPORTED
-void PNGAPI
-png_set_sBIT(png_structp png_ptr, png_infop info_ptr,
-    png_const_color_8p sig_bit)
-{
-   png_debug1(1, "in %s storage function", "sBIT");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   png_memcpy(&(info_ptr->sig_bit), sig_bit, png_sizeof(png_color_8));
-   info_ptr->valid |= PNG_INFO_sBIT;
-}
-#endif
-
-#ifdef PNG_sRGB_SUPPORTED
-void PNGAPI
-png_set_sRGB(png_structp png_ptr, png_infop info_ptr, int srgb_intent)
-{
-   png_debug1(1, "in %s storage function", "sRGB");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   info_ptr->srgb_intent = (png_byte)srgb_intent;
-   info_ptr->valid |= PNG_INFO_sRGB;
-}
-
-void PNGAPI
-png_set_sRGB_gAMA_and_cHRM(png_structp png_ptr, png_infop info_ptr,
-    int srgb_intent)
-{
-   png_debug1(1, "in %s storage function", "sRGB_gAMA_and_cHRM");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   png_set_sRGB(png_ptr, info_ptr, srgb_intent);
-
-#  ifdef PNG_gAMA_SUPPORTED
-   png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
-#  endif
-
-#  ifdef PNG_cHRM_SUPPORTED
-   png_set_cHRM_fixed(png_ptr, info_ptr,
-      /* color      x       y */
-      /* white */ 31270, 32900,
-      /* red   */ 64000, 33000,
-      /* green */ 30000, 60000,
-      /* blue  */ 15000,  6000
-   );
-#  endif /* cHRM */
-}
-#endif /* sRGB */
-
-
-#ifdef PNG_iCCP_SUPPORTED
-void PNGAPI
-png_set_iCCP(png_structp png_ptr, png_infop info_ptr,
-    png_const_charp name, int compression_type,
-    png_const_bytep profile, png_uint_32 proflen)
-{
-   png_charp new_iccp_name;
-   png_bytep new_iccp_profile;
-   png_size_t length;
-
-   png_debug1(1, "in %s storage function", "iCCP");
-
-   if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL)
-      return;
-
-   length = png_strlen(name)+1;
-   new_iccp_name = (png_charp)png_malloc_warn(png_ptr, length);
-
-   if (new_iccp_name == NULL)
-   {
-        png_warning(png_ptr, "Insufficient memory to process iCCP chunk");
-      return;
-   }
-
-   png_memcpy(new_iccp_name, name, length);
-   new_iccp_profile = (png_bytep)png_malloc_warn(png_ptr, proflen);
-
-   if (new_iccp_profile == NULL)
-   {
-      png_free (png_ptr, new_iccp_name);
-      png_warning(png_ptr,
-          "Insufficient memory to process iCCP profile");
-      return;
-   }
-
-   png_memcpy(new_iccp_profile, profile, (png_size_t)proflen);
-
-   png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0);
-
-   info_ptr->iccp_proflen = proflen;
-   info_ptr->iccp_name = new_iccp_name;
-   info_ptr->iccp_profile = new_iccp_profile;
-   /* Compression is always zero but is here so the API and info structure
-    * does not have to change if we introduce multiple compression types
-    */
-   info_ptr->iccp_compression = (png_byte)compression_type;
-   info_ptr->free_me |= PNG_FREE_ICCP;
-   info_ptr->valid |= PNG_INFO_iCCP;
-}
-#endif
-
-#ifdef PNG_TEXT_SUPPORTED
-void PNGAPI
-png_set_text(png_structp png_ptr, png_infop info_ptr, png_const_textp text_ptr,
-    int num_text)
-{
-   int ret;
-   ret = png_set_text_2(png_ptr, info_ptr, text_ptr, num_text);
-
-   if (ret)
-      png_error(png_ptr, "Insufficient memory to store text");
-}
-
-int /* PRIVATE */
-png_set_text_2(png_structp png_ptr, png_infop info_ptr,
-    png_const_textp text_ptr, int num_text)
-{
-   int i;
-
-   png_debug1(1, "in %lx storage function", png_ptr == NULL ? "unexpected" :
-      (unsigned long)png_ptr->chunk_name);
-
-   if (png_ptr == NULL || info_ptr == NULL || num_text == 0)
-      return(0);
-
-   /* Make sure we have enough space in the "text" array in info_struct
-    * to hold all of the incoming text_ptr objects.
-    */
-   if (info_ptr->num_text + num_text > info_ptr->max_text)
-   {
-      int old_max_text = info_ptr->max_text;
-      int old_num_text = info_ptr->num_text;
-
-      if (info_ptr->text != NULL)
-      {
-         png_textp old_text;
-
-         info_ptr->max_text = info_ptr->num_text + num_text + 8;
-         old_text = info_ptr->text;
-
-         info_ptr->text = (png_textp)png_malloc_warn(png_ptr,
-            (png_size_t)(info_ptr->max_text * png_sizeof(png_text)));
-
-         if (info_ptr->text == NULL)
-         {
-            /* Restore to previous condition */
-            info_ptr->max_text = old_max_text;
-            info_ptr->text = old_text;
-            return(1);
-         }
-
-         png_memcpy(info_ptr->text, old_text, (png_size_t)(old_max_text *
-             png_sizeof(png_text)));
-         png_free(png_ptr, old_text);
-      }
-
-      else
-      {
-         info_ptr->max_text = num_text + 8;
-         info_ptr->num_text = 0;
-         info_ptr->text = (png_textp)png_malloc_warn(png_ptr,
-             (png_size_t)(info_ptr->max_text * png_sizeof(png_text)));
-         if (info_ptr->text == NULL)
-         {
-            /* Restore to previous condition */
-            info_ptr->num_text = old_num_text;
-            info_ptr->max_text = old_max_text;
-            return(1);
-         }
-         info_ptr->free_me |= PNG_FREE_TEXT;
-      }
-
-      png_debug1(3, "allocated %d entries for info_ptr->text",
-          info_ptr->max_text);
-   }
-   for (i = 0; i < num_text; i++)
-   {
-      png_size_t text_length, key_len;
-      png_size_t lang_len, lang_key_len;
-      png_textp textp = &(info_ptr->text[info_ptr->num_text]);
-
-      if (text_ptr[i].key == NULL)
-          continue;
-
-      if (text_ptr[i].compression < PNG_TEXT_COMPRESSION_NONE ||
-          text_ptr[i].compression >= PNG_TEXT_COMPRESSION_LAST)
-      {
-         png_warning(png_ptr, "text compression mode is out of range");
-         continue;
-      }
-
-      key_len = png_strlen(text_ptr[i].key);
-
-      if (text_ptr[i].compression <= 0)
-      {
-         lang_len = 0;
-         lang_key_len = 0;
-      }
-
-      else
-#  ifdef PNG_iTXt_SUPPORTED
-      {
-         /* Set iTXt data */
-
-         if (text_ptr[i].lang != NULL)
-            lang_len = png_strlen(text_ptr[i].lang);
-
-         else
-            lang_len = 0;
-
-         if (text_ptr[i].lang_key != NULL)
-            lang_key_len = png_strlen(text_ptr[i].lang_key);
-
-         else
-            lang_key_len = 0;
-      }
-#  else /* PNG_iTXt_SUPPORTED */
-      {
-         png_warning(png_ptr, "iTXt chunk not supported");
-         continue;
-      }
-#  endif
-
-      if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0')
-      {
-         text_length = 0;
-#  ifdef PNG_iTXt_SUPPORTED
-         if (text_ptr[i].compression > 0)
-            textp->compression = PNG_ITXT_COMPRESSION_NONE;
-
-         else
-#  endif
-            textp->compression = PNG_TEXT_COMPRESSION_NONE;
-      }
-
-      else
-      {
-         text_length = png_strlen(text_ptr[i].text);
-         textp->compression = text_ptr[i].compression;
-      }
-
-      textp->key = (png_charp)png_malloc_warn(png_ptr,
-          (png_size_t)
-          (key_len + text_length + lang_len + lang_key_len + 4));
-
-      if (textp->key == NULL)
-         return(1);
-
-      png_debug2(2, "Allocated %lu bytes at %p in png_set_text",
-          (unsigned long)(png_uint_32)
-          (key_len + lang_len + lang_key_len + text_length + 4),
-          textp->key);
-
-      png_memcpy(textp->key, text_ptr[i].key,(png_size_t)(key_len));
-      *(textp->key + key_len) = '\0';
-
-      if (text_ptr[i].compression > 0)
-      {
-         textp->lang = textp->key + key_len + 1;
-         png_memcpy(textp->lang, text_ptr[i].lang, lang_len);
-         *(textp->lang + lang_len) = '\0';
-         textp->lang_key = textp->lang + lang_len + 1;
-         png_memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len);
-         *(textp->lang_key + lang_key_len) = '\0';
-         textp->text = textp->lang_key + lang_key_len + 1;
-      }
-
-      else
-      {
-         textp->lang=NULL;
-         textp->lang_key=NULL;
-         textp->text = textp->key + key_len + 1;
-      }
-
-      if (text_length)
-         png_memcpy(textp->text, text_ptr[i].text,
-             (png_size_t)(text_length));
-
-      *(textp->text + text_length) = '\0';
-
-#  ifdef PNG_iTXt_SUPPORTED
-      if (textp->compression > 0)
-      {
-         textp->text_length = 0;
-         textp->itxt_length = text_length;
-      }
-
-      else
-#  endif
-      {
-         textp->text_length = text_length;
-         textp->itxt_length = 0;
-      }
-
-      info_ptr->num_text++;
-      png_debug1(3, "transferred text chunk %d", info_ptr->num_text);
-   }
-   return(0);
-}
-#endif
-
-#ifdef PNG_tIME_SUPPORTED
-void PNGAPI
-png_set_tIME(png_structp png_ptr, png_infop info_ptr, png_const_timep mod_time)
-{
-   png_debug1(1, "in %s storage function", "tIME");
-
-   if (png_ptr == NULL || info_ptr == NULL ||
-       (png_ptr->mode & PNG_WROTE_tIME))
-      return;
-
-   if (mod_time->month == 0   || mod_time->month > 12  ||
-       mod_time->day   == 0   || mod_time->day   > 31  ||
-       mod_time->hour  > 23   || mod_time->minute > 59 ||
-       mod_time->second > 60)
-   {
-      png_warning(png_ptr, "Ignoring invalid time value");
-      return;
-   }
-
-   png_memcpy(&(info_ptr->mod_time), mod_time, png_sizeof(png_time));
-   info_ptr->valid |= PNG_INFO_tIME;
-}
-#endif
-
-#ifdef PNG_tRNS_SUPPORTED
-void PNGAPI
-png_set_tRNS(png_structp png_ptr, png_infop info_ptr,
-    png_const_bytep trans_alpha, int num_trans, png_const_color_16p trans_color)
-{
-   png_debug1(1, "in %s storage function", "tRNS");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   if (trans_alpha != NULL)
-   {
-       /* It may not actually be necessary to set png_ptr->trans_alpha here;
-        * we do it for backward compatibility with the way the png_handle_tRNS
-        * function used to do the allocation.
-        */
-
-       png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
-
-       /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
-       png_ptr->trans_alpha = info_ptr->trans_alpha =
-           (png_bytep)png_malloc(png_ptr, (png_size_t)PNG_MAX_PALETTE_LENGTH);
-
-       if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
-          png_memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans);
-   }
-
-   if (trans_color != NULL)
-   {
-      int sample_max = (1 << info_ptr->bit_depth);
-
-      if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
-          (int)trans_color->gray > sample_max) ||
-          (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
-          ((int)trans_color->red > sample_max ||
-          (int)trans_color->green > sample_max ||
-          (int)trans_color->blue > sample_max)))
-         png_warning(png_ptr,
-            "tRNS chunk has out-of-range samples for bit_depth");
-
-      png_memcpy(&(info_ptr->trans_color), trans_color,
-         png_sizeof(png_color_16));
-
-      if (num_trans == 0)
-         num_trans = 1;
-   }
-
-   info_ptr->num_trans = (png_uint_16)num_trans;
-
-   if (num_trans != 0)
-   {
-      info_ptr->valid |= PNG_INFO_tRNS;
-      info_ptr->free_me |= PNG_FREE_TRNS;
-   }
-}
-#endif
-
-#ifdef PNG_sPLT_SUPPORTED
-void PNGAPI
-png_set_sPLT(png_structp png_ptr,
-    png_infop info_ptr, png_const_sPLT_tp entries, int nentries)
-/*
- *  entries        - array of png_sPLT_t structures
- *                   to be added to the list of palettes
- *                   in the info structure.
- *
- *  nentries       - number of palette structures to be
- *                   added.
- */
-{
-   png_sPLT_tp np;
-   int i;
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   np = (png_sPLT_tp)png_malloc_warn(png_ptr,
-       (info_ptr->splt_palettes_num + nentries) *
-       (png_size_t)png_sizeof(png_sPLT_t));
-
-   if (np == NULL)
-   {
-      png_warning(png_ptr, "No memory for sPLT palettes");
-      return;
-   }
-
-   png_memcpy(np, info_ptr->splt_palettes,
-       info_ptr->splt_palettes_num * png_sizeof(png_sPLT_t));
-
-   png_free(png_ptr, info_ptr->splt_palettes);
-   info_ptr->splt_palettes=NULL;
-
-   for (i = 0; i < nentries; i++)
-   {
-      png_sPLT_tp to = np + info_ptr->splt_palettes_num + i;
-      png_const_sPLT_tp from = entries + i;
-      png_size_t length;
-
-      length = png_strlen(from->name) + 1;
-      to->name = (png_charp)png_malloc_warn(png_ptr, length);
-
-      if (to->name == NULL)
-      {
-         png_warning(png_ptr,
-             "Out of memory while processing sPLT chunk");
-         continue;
-      }
-
-      png_memcpy(to->name, from->name, length);
-      to->entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
-          from->nentries * png_sizeof(png_sPLT_entry));
-
-      if (to->entries == NULL)
-      {
-         png_warning(png_ptr,
-             "Out of memory while processing sPLT chunk");
-         png_free(png_ptr, to->name);
-         to->name = NULL;
-         continue;
-      }
-
-      png_memcpy(to->entries, from->entries,
-          from->nentries * png_sizeof(png_sPLT_entry));
-
-      to->nentries = from->nentries;
-      to->depth = from->depth;
-   }
-
-   info_ptr->splt_palettes = np;
-   info_ptr->splt_palettes_num += nentries;
-   info_ptr->valid |= PNG_INFO_sPLT;
-   info_ptr->free_me |= PNG_FREE_SPLT;
-}
-#endif /* PNG_sPLT_SUPPORTED */
-
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-void PNGAPI
-png_set_unknown_chunks(png_structp png_ptr,
-   png_infop info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
-{
-   png_unknown_chunkp np;
-   int i;
-
-   if (png_ptr == NULL || info_ptr == NULL || num_unknowns == 0)
-      return;
-
-   np = (png_unknown_chunkp)png_malloc_warn(png_ptr,
-       (png_size_t)(info_ptr->unknown_chunks_num + num_unknowns) *
-       png_sizeof(png_unknown_chunk));
-
-   if (np == NULL)
-   {
-      png_warning(png_ptr,
-          "Out of memory while processing unknown chunk");
-      return;
-   }
-
-   png_memcpy(np, info_ptr->unknown_chunks,
-       (png_size_t)info_ptr->unknown_chunks_num *
-       png_sizeof(png_unknown_chunk));
-
-   png_free(png_ptr, info_ptr->unknown_chunks);
-   info_ptr->unknown_chunks = NULL;
-
-   for (i = 0; i < num_unknowns; i++)
-   {
-      png_unknown_chunkp to = np + info_ptr->unknown_chunks_num + i;
-      png_const_unknown_chunkp from = unknowns + i;
-
-      png_memcpy(to->name, from->name, png_sizeof(from->name));
-      to->name[png_sizeof(to->name)-1] = '\0';
-      to->size = from->size;
-
-      /* Note our location in the read or write sequence */
-      to->location = (png_byte)(png_ptr->mode & 0xff);
-
-      if (from->size == 0)
-         to->data=NULL;
-
-      else
-      {
-         to->data = (png_bytep)png_malloc_warn(png_ptr,
-             (png_size_t)from->size);
-
-         if (to->data == NULL)
-         {
-            png_warning(png_ptr,
-                "Out of memory while processing unknown chunk");
-            to->size = 0;
-         }
-
-         else
-            png_memcpy(to->data, from->data, from->size);
-      }
-   }
-
-   info_ptr->unknown_chunks = np;
-   info_ptr->unknown_chunks_num += num_unknowns;
-   info_ptr->free_me |= PNG_FREE_UNKN;
-}
-
-void PNGAPI
-png_set_unknown_chunk_location(png_structp png_ptr, png_infop info_ptr,
-    int chunk, int location)
-{
-   if (png_ptr != NULL && info_ptr != NULL && chunk >= 0 && chunk <
-       info_ptr->unknown_chunks_num)
-      info_ptr->unknown_chunks[chunk].location = (png_byte)location;
-}
-#endif
-
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-png_uint_32 PNGAPI
-png_permit_mng_features (png_structp png_ptr, png_uint_32 mng_features)
-{
-   png_debug(1, "in png_permit_mng_features");
-
-   if (png_ptr == NULL)
-      return (png_uint_32)0;
-
-   png_ptr->mng_features_permitted =
-       (png_byte)(mng_features & PNG_ALL_MNG_FEATURES);
-
-   return (png_uint_32)png_ptr->mng_features_permitted;
-}
-#endif
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-void PNGAPI
-png_set_keep_unknown_chunks(png_structp png_ptr, int keep, png_const_bytep
-    chunk_list, int num_chunks)
-{
-   png_bytep new_list, p;
-   int i, old_num_chunks;
-   if (png_ptr == NULL)
-      return;
-
-   if (num_chunks == 0)
-   {
-      if (keep == PNG_HANDLE_CHUNK_ALWAYS || keep == PNG_HANDLE_CHUNK_IF_SAFE)
-         png_ptr->flags |= PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
-
-      else
-         png_ptr->flags &= ~PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
-
-      if (keep == PNG_HANDLE_CHUNK_ALWAYS)
-         png_ptr->flags |= PNG_FLAG_KEEP_UNSAFE_CHUNKS;
-
-      else
-         png_ptr->flags &= ~PNG_FLAG_KEEP_UNSAFE_CHUNKS;
-
-      return;
-   }
-
-   if (chunk_list == NULL)
-      return;
-
-   old_num_chunks = png_ptr->num_chunk_list;
-   new_list=(png_bytep)png_malloc(png_ptr,
-       (png_size_t)(5*(num_chunks + old_num_chunks)));
-
-   if (png_ptr->chunk_list != NULL)
-   {
-      png_memcpy(new_list, png_ptr->chunk_list,
-          (png_size_t)(5*old_num_chunks));
-      png_free(png_ptr, png_ptr->chunk_list);
-      png_ptr->chunk_list=NULL;
-   }
-
-   png_memcpy(new_list + 5*old_num_chunks, chunk_list,
-       (png_size_t)(5*num_chunks));
-
-   for (p = new_list + 5*old_num_chunks + 4, i = 0; i<num_chunks; i++, p += 5)
-      *p=(png_byte)keep;
-
-   png_ptr->num_chunk_list = old_num_chunks + num_chunks;
-   png_ptr->chunk_list = new_list;
-   png_ptr->free_me |= PNG_FREE_LIST;
-}
-#endif
-
-#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
-void PNGAPI
-png_set_read_user_chunk_fn(png_structp png_ptr, png_voidp user_chunk_ptr,
-    png_user_chunk_ptr read_user_chunk_fn)
-{
-   png_debug(1, "in png_set_read_user_chunk_fn");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->read_user_chunk_fn = read_user_chunk_fn;
-   png_ptr->user_chunk_ptr = user_chunk_ptr;
-}
-#endif
-
-#ifdef PNG_INFO_IMAGE_SUPPORTED
-void PNGAPI
-png_set_rows(png_structp png_ptr, png_infop info_ptr, png_bytepp row_pointers)
-{
-   png_debug1(1, "in %s storage function", "rows");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   if (info_ptr->row_pointers && (info_ptr->row_pointers != row_pointers))
-      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
-
-   info_ptr->row_pointers = row_pointers;
-
-   if (row_pointers)
-      info_ptr->valid |= PNG_INFO_IDAT;
-}
-#endif
-
-void PNGAPI
-png_set_compression_buffer_size(png_structp png_ptr, png_size_t size)
-{
-    if (png_ptr == NULL)
-       return;
-
-    png_free(png_ptr, png_ptr->zbuf);
-
-    if (size > ZLIB_IO_MAX)
-    {
-       png_warning(png_ptr, "Attempt to set buffer size beyond max ignored");
-       png_ptr->zbuf_size = ZLIB_IO_MAX;
-       size = ZLIB_IO_MAX; /* must fit */
-    }
-
-    else
-       png_ptr->zbuf_size = (uInt)size;
-
-    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr, size);
-
-    /* The following ensures a relatively safe failure if this gets called while
-     * the buffer is actually in use.
-     */
-    png_ptr->zstream.next_out = png_ptr->zbuf;
-    png_ptr->zstream.avail_out = 0;
-    png_ptr->zstream.avail_in = 0;
-}
-
-void PNGAPI
-png_set_invalid(png_structp png_ptr, png_infop info_ptr, int mask)
-{
-   if (png_ptr && info_ptr)
-      info_ptr->valid &= ~mask;
-}
-
-
-
-#ifdef PNG_SET_USER_LIMITS_SUPPORTED
-/* This function was added to libpng 1.2.6 */
-void PNGAPI
-png_set_user_limits (png_structp png_ptr, png_uint_32 user_width_max,
-    png_uint_32 user_height_max)
-{
-   /* Images with dimensions larger than these limits will be
-    * rejected by png_set_IHDR().  To accept any PNG datastream
-    * regardless of dimensions, set both limits to 0x7ffffffL.
-    */
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->user_width_max = user_width_max;
-   png_ptr->user_height_max = user_height_max;
-}
-
-/* This function was added to libpng 1.4.0 */
-void PNGAPI
-png_set_chunk_cache_max (png_structp png_ptr,
-   png_uint_32 user_chunk_cache_max)
-{
-    if (png_ptr)
-       png_ptr->user_chunk_cache_max = user_chunk_cache_max;
-}
-
-/* This function was added to libpng 1.4.1 */
-void PNGAPI
-png_set_chunk_malloc_max (png_structp png_ptr,
-    png_alloc_size_t user_chunk_malloc_max)
-{
-   if (png_ptr)
-      png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
-}
-#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */
-
-
-#ifdef PNG_BENIGN_ERRORS_SUPPORTED
-void PNGAPI
-png_set_benign_errors(png_structp png_ptr, int allowed)
-{
-   png_debug(1, "in png_set_benign_errors");
-
-   if (allowed)
-      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
-
-   else
-      png_ptr->flags &= ~PNG_FLAG_BENIGN_ERRORS_WARN;
-}
-#endif /* PNG_BENIGN_ERRORS_SUPPORTED */
-
-#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
-   /* Do not report invalid palette index; added at libng-1.5.10 */
-void PNGAPI
-png_set_check_for_invalid_index(png_structp png_ptr, int allowed)
-{
-   png_debug(1, "in png_set_check_for_invalid_index");
-
-   if (allowed)
-      png_ptr->num_palette_max = 0;
-
-   else
-      png_ptr->num_palette_max = -1;
-}
-#endif
-
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/extern/libpng/include/pngstruct.h b/extern/libpng/include/pngstruct.h
deleted file mode 100644
index 43a45cdec6..0000000000
--- a/extern/libpng/include/pngstruct.h
+++ /dev/null
@@ -1,357 +0,0 @@
-
-/* pngstruct.h - header file for PNG reference library
- *
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * Last changed in libpng 1.5.9 [March 29, 2012]
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-/* The structure that holds the information to read and write PNG files.
- * The only people who need to care about what is inside of this are the
- * people who will be modifying the library for their own special needs.
- * It should NOT be accessed directly by an application.
- */
-
-#ifndef PNGSTRUCT_H
-#define PNGSTRUCT_H
-/* zlib.h defines the structure z_stream, an instance of which is included
- * in this structure and is required for decompressing the LZ compressed
- * data in PNG files.
- */
-#include "zlib.h"
-
-struct png_struct_def
-{
-#ifdef PNG_SETJMP_SUPPORTED
-   jmp_buf longjmp_buffer;    /* used in png_error */
-   png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
-#endif
-   png_error_ptr error_fn;    /* function for printing errors and aborting */
-#ifdef PNG_WARNINGS_SUPPORTED
-   png_error_ptr warning_fn;  /* function for printing warnings */
-#endif
-   png_voidp error_ptr;       /* user supplied struct for error functions */
-   png_rw_ptr write_data_fn;  /* function for writing output data */
-   png_rw_ptr read_data_fn;   /* function for reading input data */
-   png_voidp io_ptr;          /* ptr to application struct for I/O functions */
-
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-   png_user_transform_ptr read_user_transform_fn; /* user read transform */
-#endif
-
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-   png_user_transform_ptr write_user_transform_fn; /* user write transform */
-#endif
-
-/* These were added in libpng-1.0.2 */
-#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
-    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
-   png_voidp user_transform_ptr; /* user supplied struct for user transform */
-   png_byte user_transform_depth;    /* bit depth of user transformed pixels */
-   png_byte user_transform_channels; /* channels in user transformed pixels */
-#endif
-#endif
-
-   png_uint_32 mode;          /* tells us where we are in the PNG file */
-   png_uint_32 flags;         /* flags indicating various things to libpng */
-   png_uint_32 transformations; /* which transformations to perform */
-
-   z_stream zstream;          /* pointer to decompression structure (below) */
-   png_bytep zbuf;            /* buffer for zlib */
-   uInt zbuf_size;            /* size of zbuf (typically 65536) */
-#ifdef PNG_WRITE_SUPPORTED
-
-/* Added in 1.5.4: state to keep track of whether the zstream has been
- * initialized and if so whether it is for IDAT or some other chunk.
- */
-#define PNG_ZLIB_UNINITIALIZED 0
-#define PNG_ZLIB_FOR_IDAT      1
-#define PNG_ZLIB_FOR_TEXT      2 /* anything other than IDAT */
-#define PNG_ZLIB_USE_MASK      3 /* bottom two bits */
-#define PNG_ZLIB_IN_USE        4 /* a flag value */
-
-   png_uint_32 zlib_state;       /* State of zlib initialization */
-/* End of material added at libpng 1.5.4 */
-
-   int zlib_level;            /* holds zlib compression level */
-   int zlib_method;           /* holds zlib compression method */
-   int zlib_window_bits;      /* holds zlib compression window bits */
-   int zlib_mem_level;        /* holds zlib compression memory level */
-   int zlib_strategy;         /* holds zlib compression strategy */
-#endif
-/* Added at libpng 1.5.4 */
-#if defined(PNG_WRITE_COMPRESSED_TEXT_SUPPORTED) || \
-    defined(PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED)
-   int zlib_text_level;            /* holds zlib compression level */
-   int zlib_text_method;           /* holds zlib compression method */
-   int zlib_text_window_bits;      /* holds zlib compression window bits */
-   int zlib_text_mem_level;        /* holds zlib compression memory level */
-   int zlib_text_strategy;         /* holds zlib compression strategy */
-#endif
-/* End of material added at libpng 1.5.4 */
-
-   png_uint_32 width;         /* width of image in pixels */
-   png_uint_32 height;        /* height of image in pixels */
-   png_uint_32 num_rows;      /* number of rows in current pass */
-   png_uint_32 usr_width;     /* width of row at start of write */
-   png_size_t rowbytes;       /* size of row in bytes */
-   png_uint_32 iwidth;        /* width of current interlaced row in pixels */
-   png_uint_32 row_number;    /* current row in interlace pass */
-   png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
-   png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
-                               * This is a pointer into big_prev_row
-                               */
-   png_bytep row_buf;         /* buffer to save current (unfiltered) row.
-                               * This is a pointer into big_row_buf
-                               */
-   png_bytep sub_row;         /* buffer to save "sub" row when filtering */
-   png_bytep up_row;          /* buffer to save "up" row when filtering */
-   png_bytep avg_row;         /* buffer to save "avg" row when filtering */
-   png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
-   png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
-
-   png_uint_32 idat_size;     /* current IDAT size for read */
-   png_uint_32 crc;           /* current chunk CRC value */
-   png_colorp palette;        /* palette from the input file */
-   png_uint_16 num_palette;   /* number of color entries in palette */
-
-/* Added at libpng-1.5.10 */
-#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
-   int num_palette_max;       /* maximum palette index found in IDAT */
-#endif
-
-   png_uint_16 num_trans;     /* number of transparency values */
-   png_byte compression;      /* file compression type (always 0) */
-   png_byte filter;           /* file filter type (always 0) */
-   png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
-   png_byte pass;             /* current interlace pass (0 - 6) */
-   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
-   png_byte color_type;       /* color type of file */
-   png_byte bit_depth;        /* bit depth of file */
-   png_byte usr_bit_depth;    /* bit depth of users row: write only */
-   png_byte pixel_depth;      /* number of bits per pixel */
-   png_byte channels;         /* number of channels in file */
-   png_byte usr_channels;     /* channels at start of write: write only */
-   png_byte sig_bytes;        /* magic bytes read/written from start of file */
-   png_byte maximum_pixel_depth;
-                              /* pixel depth used for the row buffers */
-   png_byte transformed_pixel_depth;
-                              /* pixel depth after read/write transforms */
-   png_byte io_chunk_string[5];
-                              /* string name of chunk */
-
-#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
-   png_uint_16 filler;           /* filler bytes for pixel expansion */
-#endif
-
-#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   png_byte background_gamma_type;
-   png_fixed_point background_gamma;
-   png_color_16 background;   /* background color in screen gamma space */
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   png_color_16 background_1; /* background normalized to gamma 1.0 */
-#endif
-#endif /* PNG_bKGD_SUPPORTED */
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-   png_flush_ptr output_flush_fn; /* Function for flushing output */
-   png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
-   png_uint_32 flush_rows;    /* number of rows written since last flush */
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
-   png_fixed_point gamma;        /* file gamma value */
-   png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
-
-   png_bytep gamma_table;     /* gamma table for 8-bit depth files */
-   png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
-   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-   png_bytep gamma_from_1;    /* converts from 1.0 to screen */
-   png_bytep gamma_to_1;      /* converts from file to 1.0 */
-   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
-   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
-#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
-#endif
-
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
-   png_color_8 sig_bit;       /* significant bits in each available channel */
-#endif
-
-#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
-   png_color_8 shift;         /* shift for significant bit tranformation */
-#endif
-
-#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
- || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
-   png_bytep trans_alpha;           /* alpha values for paletted files */
-   png_color_16 trans_color;  /* transparent color for non-paletted files */
-#endif
-
-   png_read_status_ptr read_row_fn;   /* called after each row is decoded */
-   png_write_status_ptr write_row_fn; /* called after each row is encoded */
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-   png_progressive_info_ptr info_fn; /* called after header data fully read */
-   png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
-   png_progressive_end_ptr end_fn;   /* called after image is complete */
-   png_bytep save_buffer_ptr;        /* current location in save_buffer */
-   png_bytep save_buffer;            /* buffer for previously read data */
-   png_bytep current_buffer_ptr;     /* current location in current_buffer */
-   png_bytep current_buffer;         /* buffer for recently used data */
-   png_uint_32 push_length;          /* size of current input chunk */
-   png_uint_32 skip_length;          /* bytes to skip in input data */
-   png_size_t save_buffer_size;      /* amount of data now in save_buffer */
-   png_size_t save_buffer_max;       /* total size of save_buffer */
-   png_size_t buffer_size;           /* total amount of available input data */
-   png_size_t current_buffer_size;   /* amount of data now in current_buffer */
-   int process_mode;                 /* what push library is currently doing */
-   int cur_palette;                  /* current push library palette index */
-
-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
-
-#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
-/* For the Borland special 64K segment handler */
-   png_bytepp offset_table_ptr;
-   png_bytep offset_table;
-   png_uint_16 offset_table_number;
-   png_uint_16 offset_table_count;
-   png_uint_16 offset_table_count_free;
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-   png_bytep palette_lookup; /* lookup table for quantizing */
-   png_bytep quantize_index; /* index translation for palette files */
-#endif
-
-#if defined(PNG_READ_QUANTIZE_SUPPORTED) || defined(PNG_hIST_SUPPORTED)
-   png_uint_16p hist;                /* histogram */
-#endif
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   png_byte heuristic_method;        /* heuristic for row filter selection */
-   png_byte num_prev_filters;        /* number of weights for previous rows */
-   png_bytep prev_filters;           /* filter type(s) of previous row(s) */
-   png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
-   png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
-   png_uint_16p filter_costs;        /* relative filter calculation cost */
-   png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
-#endif
-
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-   char time_buffer[29]; /* String to hold RFC 1123 time text */
-#endif
-
-/* New members added in libpng-1.0.6 */
-
-   png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
-
-#ifdef PNG_USER_CHUNKS_SUPPORTED
-   png_voidp user_chunk_ptr;
-   png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
-#endif
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-   int num_chunk_list;
-   png_bytep chunk_list;
-#endif
-
-#ifdef PNG_READ_sRGB_SUPPORTED
-   /* Added in 1.5.5 to record an sRGB chunk in the png. */
-   png_byte is_sRGB;
-#endif
-
-/* New members added in libpng-1.0.3 */
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   png_byte rgb_to_gray_status;
-   /* Added in libpng 1.5.5 to record setting of coefficients: */
-   png_byte rgb_to_gray_coefficients_set;
-   /* These were changed from png_byte in libpng-1.0.6 */
-   png_uint_16 rgb_to_gray_red_coeff;
-   png_uint_16 rgb_to_gray_green_coeff;
-   /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
-#endif
-
-/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
-#if defined(PNG_MNG_FEATURES_SUPPORTED)
-/* Changed from png_byte to png_uint_32 at version 1.2.0 */
-   png_uint_32 mng_features_permitted;
-#endif
-
-/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-   png_byte filter_type;
-#endif
-
-/* New members added in libpng-1.2.0 */
-
-/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_voidp mem_ptr;             /* user supplied struct for mem functions */
-   png_malloc_ptr malloc_fn;      /* function for allocating memory */
-   png_free_ptr free_fn;          /* function for freeing memory */
-#endif
-
-/* New member added in libpng-1.0.13 and 1.2.0 */
-   png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-/* The following three members were added at version 1.0.14 and 1.2.4 */
-   png_bytep quantize_sort;          /* working sort array */
-   png_bytep index_to_palette;       /* where the original index currently is
-                                        in the palette */
-   png_bytep palette_to_index;       /* which original index points to this
-                                         palette color */
-#endif
-
-/* New members added in libpng-1.0.16 and 1.2.6 */
-   png_byte compression_type;
-
-#ifdef PNG_USER_LIMITS_SUPPORTED
-   png_uint_32 user_width_max;
-   png_uint_32 user_height_max;
-
-   /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
-    * chunks that can be stored (0 means unlimited).
-    */
-   png_uint_32 user_chunk_cache_max;
-
-   /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
-    * can occupy when decompressed.  0 means unlimited.
-    */
-   png_alloc_size_t user_chunk_malloc_max;
-#endif
-
-/* New member added in libpng-1.0.25 and 1.2.17 */
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-   /* Storage for unknown chunk that the library doesn't recognize. */
-   png_unknown_chunk unknown_chunk;
-#endif
-
-/* New member added in libpng-1.2.26 */
-  png_size_t old_big_row_buf_size;
-
-/* New member added in libpng-1.2.30 */
-  png_charp chunkdata;  /* buffer for reading chunk data */
-
-#ifdef PNG_IO_STATE_SUPPORTED
-/* New member added in libpng-1.4.0 */
-   png_uint_32 io_state;
-#endif
-
-/* New member added in libpng-1.5.6 */
-   png_bytep big_prev_row;
-
-   void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
-      png_bytep row, png_const_bytep prev_row);
-};
-#endif /* PNGSTRUCT_H */
diff --git a/extern/libpng/include/pngtest.c b/extern/libpng/include/pngtest.c
deleted file mode 100644
index 0295840baa..0000000000
--- a/extern/libpng/include/pngtest.c
+++ /dev/null
@@ -1,1820 +0,0 @@
-
-/* pngtest.c - a simple test program to test libpng
- *
- * Last changed in libpng 1.5.6 [November 3, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * This program reads in a PNG image, writes it out again, and then
- * compares the two files.  If the files are identical, this shows that
- * the basic chunk handling, filtering, and (de)compression code is working
- * properly.  It does not currently test all of the transforms, although
- * it probably should.
- *
- * The program will report "FAIL" in certain legitimate cases:
- * 1) when the compression level or filter selection method is changed.
- * 2) when the maximum IDAT size (PNG_ZBUF_SIZE in pngconf.h) is not 8192.
- * 3) unknown unsafe-to-copy ancillary chunks or unknown critical chunks
- *    exist in the input file.
- * 4) others not listed here...
- * In these cases, it is best to check with another tool such as "pngcheck"
- * to see what the differences between the two files are.
- *
- * If a filename is given on the command-line, then this file is used
- * for the input, rather than the default "pngtest.png".  This allows
- * testing a wide variety of files easily.  You can also test a number
- * of files at once by typing "pngtest -m file1.png file2.png ..."
- */
-
-#define _POSIX_SOURCE 1
-
-#include "zlib.h"
-#include "png.h"
-/* Copied from pngpriv.h but only used in error messages below. */
-#ifndef PNG_ZBUF_SIZE
-#  define PNG_ZBUF_SIZE 8192
-#endif
-#  include <stdio.h>
-#  include <stdlib.h>
-#  include <string.h>
-#  define FCLOSE(file) fclose(file)
-
-#ifndef PNG_STDIO_SUPPORTED
-typedef FILE                * png_FILE_p;
-#endif
-
-/* Makes pngtest verbose so we can find problems. */
-#ifndef PNG_DEBUG
-#  define PNG_DEBUG 0
-#endif
-
-#if PNG_DEBUG > 1
-#  define pngtest_debug(m)        ((void)fprintf(stderr, m "\n"))
-#  define pngtest_debug1(m,p1)    ((void)fprintf(stderr, m "\n", p1))
-#  define pngtest_debug2(m,p1,p2) ((void)fprintf(stderr, m "\n", p1, p2))
-#else
-#  define pngtest_debug(m)        ((void)0)
-#  define pngtest_debug1(m,p1)    ((void)0)
-#  define pngtest_debug2(m,p1,p2) ((void)0)
-#endif
-
-#if !PNG_DEBUG
-#  define SINGLE_ROWBUF_ALLOC  /* Makes buffer overruns easier to nail */
-#endif
-
-/* The code uses memcmp and memcpy on large objects (typically row pointers) so
- * it is necessary to do soemthing special on certain architectures, note that
- * the actual support for this was effectively removed in 1.4, so only the
- * memory remains in this program:
- */
-#define CVT_PTR(ptr)         (ptr)
-#define CVT_PTR_NOCHECK(ptr) (ptr)
-#define png_memcmp  memcmp
-#define png_memcpy  memcpy
-#define png_memset  memset
-
-/* Turn on CPU timing
-#define PNGTEST_TIMING
-*/
-
-#ifndef PNG_FLOATING_POINT_SUPPORTED
-#undef PNGTEST_TIMING
-#endif
-
-#ifdef PNGTEST_TIMING
-static float t_start, t_stop, t_decode, t_encode, t_misc;
-#include <time.h>
-#endif
-
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-#define PNG_tIME_STRING_LENGTH 29
-static int tIME_chunk_present = 0;
-static char tIME_string[PNG_tIME_STRING_LENGTH] = "tIME chunk is not present";
-#endif
-
-static int verbose = 0;
-static int strict = 0;
-
-int test_one_file PNGARG((PNG_CONST char *inname, PNG_CONST char *outname));
-
-#ifdef __TURBOC__
-#include <mem.h>
-#endif
-
-/* Defined so I can write to a file on gui/windowing platforms */
-/*  #define STDERR stderr  */
-#define STDERR stdout   /* For DOS */
-
-/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
-#ifndef png_jmpbuf
-#  define png_jmpbuf(png_ptr) png_ptr->jmpbuf
-#endif
-
-/* Example of using row callbacks to make a simple progress meter */
-static int status_pass = 1;
-static int status_dots_requested = 0;
-static int status_dots = 1;
-
-void PNGCBAPI
-read_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass);
-void PNGCBAPI
-read_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
-{
-   if (png_ptr == NULL || row_number > PNG_UINT_31_MAX)
-      return;
-
-   if (status_pass != pass)
-   {
-      fprintf(stdout, "\n Pass %d: ", pass);
-      status_pass = pass;
-      status_dots = 31;
-   }
-
-   status_dots--;
-
-   if (status_dots == 0)
-   {
-      fprintf(stdout, "\n         ");
-      status_dots=30;
-   }
-
-   fprintf(stdout, "r");
-}
-
-void PNGCBAPI
-write_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass);
-void PNGCBAPI
-write_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
-{
-   if (png_ptr == NULL || row_number > PNG_UINT_31_MAX || pass > 7)
-      return;
-
-   fprintf(stdout, "w");
-}
-
-
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-/* Example of using user transform callback (we don't transform anything,
- * but merely examine the row filters.  We set this to 256 rather than
- * 5 in case illegal filter values are present.)
- */
-static png_uint_32 filters_used[256];
-void PNGCBAPI
-count_filters(png_structp png_ptr, png_row_infop row_info, png_bytep data);
-void PNGCBAPI
-count_filters(png_structp png_ptr, png_row_infop row_info, png_bytep data)
-{
-   if (png_ptr != NULL && row_info != NULL)
-      ++filters_used[*(data - 1)];
-}
-#endif
-
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-/* Example of using user transform callback (we don't transform anything,
- * but merely count the zero samples)
- */
-
-static png_uint_32 zero_samples;
-
-void PNGCBAPI
-count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data);
-void PNGCBAPI
-count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
-{
-   png_bytep dp = data;
-   if (png_ptr == NULL)
-      return;
-
-   /* Contents of row_info:
-    *  png_uint_32 width      width of row
-    *  png_uint_32 rowbytes   number of bytes in row
-    *  png_byte color_type    color type of pixels
-    *  png_byte bit_depth     bit depth of samples
-    *  png_byte channels      number of channels (1-4)
-    *  png_byte pixel_depth   bits per pixel (depth*channels)
-    */
-
-    /* Counts the number of zero samples (or zero pixels if color_type is 3 */
-
-    if (row_info->color_type == 0 || row_info->color_type == 3)
-    {
-       int pos = 0;
-       png_uint_32 n, nstop;
-
-       for (n = 0, nstop=row_info->width; n<nstop; n++)
-       {
-          if (row_info->bit_depth == 1)
-          {
-             if (((*dp << pos++ ) & 0x80) == 0)
-                zero_samples++;
-
-             if (pos == 8)
-             {
-                pos = 0;
-                dp++;
-             }
-          }
-
-          if (row_info->bit_depth == 2)
-          {
-             if (((*dp << (pos+=2)) & 0xc0) == 0)
-                zero_samples++;
-
-             if (pos == 8)
-             {
-                pos = 0;
-                dp++;
-             }
-          }
-
-          if (row_info->bit_depth == 4)
-          {
-             if (((*dp << (pos+=4)) & 0xf0) == 0)
-                zero_samples++;
-
-             if (pos == 8)
-             {
-                pos = 0;
-                dp++;
-             }
-          }
-
-          if (row_info->bit_depth == 8)
-             if (*dp++ == 0)
-                zero_samples++;
-
-          if (row_info->bit_depth == 16)
-          {
-             if ((*dp | *(dp+1)) == 0)
-                zero_samples++;
-             dp+=2;
-          }
-       }
-    }
-    else /* Other color types */
-    {
-       png_uint_32 n, nstop;
-       int channel;
-       int color_channels = row_info->channels;
-       if (row_info->color_type > 3)color_channels--;
-
-       for (n = 0, nstop=row_info->width; n<nstop; n++)
-       {
-          for (channel = 0; channel < color_channels; channel++)
-          {
-             if (row_info->bit_depth == 8)
-                if (*dp++ == 0)
-                   zero_samples++;
-
-             if (row_info->bit_depth == 16)
-             {
-                if ((*dp | *(dp+1)) == 0)
-                   zero_samples++;
-
-                dp+=2;
-             }
-          }
-          if (row_info->color_type > 3)
-          {
-             dp++;
-             if (row_info->bit_depth == 16)
-                dp++;
-          }
-       }
-    }
-}
-#endif /* PNG_WRITE_USER_TRANSFORM_SUPPORTED */
-
-static int wrote_question = 0;
-
-#ifndef PNG_STDIO_SUPPORTED
-/* START of code to validate stdio-free compilation */
-/* These copies of the default read/write functions come from pngrio.c and
- * pngwio.c.  They allow "don't include stdio" testing of the library.
- * This is the function that does the actual reading of data.  If you are
- * not reading from a standard C stream, you should create a replacement
- * read_data function and use it at run time with png_set_read_fn(), rather
- * than changing the library.
- */
-
-#ifdef PNG_IO_STATE_SUPPORTED
-void
-pngtest_check_io_state(png_structp png_ptr, png_size_t data_length,
-   png_uint_32 io_op);
-void
-pngtest_check_io_state(png_structp png_ptr, png_size_t data_length,
-   png_uint_32 io_op)
-{
-   png_uint_32 io_state = png_get_io_state(png_ptr);
-   int err = 0;
-
-   /* Check if the current operation (reading / writing) is as expected. */
-   if ((io_state & PNG_IO_MASK_OP) != io_op)
-      png_error(png_ptr, "Incorrect operation in I/O state");
-
-   /* Check if the buffer size specific to the current location
-    * (file signature / header / data / crc) is as expected.
-    */
-   switch (io_state & PNG_IO_MASK_LOC)
-   {
-   case PNG_IO_SIGNATURE:
-      if (data_length > 8)
-         err = 1;
-      break;
-   case PNG_IO_CHUNK_HDR:
-      if (data_length != 8)
-         err = 1;
-      break;
-   case PNG_IO_CHUNK_DATA:
-      break;  /* no restrictions here */
-   case PNG_IO_CHUNK_CRC:
-      if (data_length != 4)
-         err = 1;
-      break;
-   default:
-      err = 1;  /* uninitialized */
-   }
-   if (err)
-      png_error(png_ptr, "Bad I/O state or buffer size");
-}
-#endif
-
-#ifndef USE_FAR_KEYWORD
-static void PNGCBAPI
-pngtest_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_size_t check = 0;
-   png_voidp io_ptr;
-
-   /* fread() returns 0 on error, so it is OK to store this in a png_size_t
-    * instead of an int, which is what fread() actually returns.
-    */
-   io_ptr = png_get_io_ptr(png_ptr);
-   if (io_ptr != NULL)
-   {
-      check = fread(data, 1, length, (png_FILE_p)io_ptr);
-   }
-
-   if (check != length)
-   {
-      png_error(png_ptr, "Read Error");
-   }
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   pngtest_check_io_state(png_ptr, length, PNG_IO_READING);
-#endif
-}
-#else
-/* This is the model-independent version. Since the standard I/O library
-   can't handle far buffers in the medium and small models, we have to copy
-   the data.
-*/
-
-#define NEAR_BUF_SIZE 1024
-#define MIN(a,b) (a <= b ? a : b)
-
-static void PNGCBAPI
-pngtest_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_size_t check;
-   png_byte *n_data;
-   png_FILE_p io_ptr;
-
-   /* Check if data really is near. If so, use usual code. */
-   n_data = (png_byte *)CVT_PTR_NOCHECK(data);
-   io_ptr = (png_FILE_p)CVT_PTR(png_get_io_ptr(png_ptr));
-   if ((png_bytep)n_data == data)
-   {
-      check = fread(n_data, 1, length, io_ptr);
-   }
-   else
-   {
-      png_byte buf[NEAR_BUF_SIZE];
-      png_size_t read, remaining, err;
-      check = 0;
-      remaining = length;
-
-      do
-      {
-         read = MIN(NEAR_BUF_SIZE, remaining);
-         err = fread(buf, 1, 1, io_ptr);
-         png_memcpy(data, buf, read); /* Copy far buffer to near buffer */
-         if (err != read)
-            break;
-         else
-            check += err;
-         data += read;
-         remaining -= read;
-      }
-      while (remaining != 0);
-   }
-
-   if (check != length)
-      png_error(png_ptr, "Read Error");
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   pngtest_check_io_state(png_ptr, length, PNG_IO_READING);
-#endif
-}
-#endif /* USE_FAR_KEYWORD */
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-static void PNGCBAPI
-pngtest_flush(png_structp png_ptr)
-{
-   /* Do nothing; fflush() is said to be just a waste of energy. */
-   PNG_UNUSED(png_ptr)   /* Stifle compiler warning */
-}
-#endif
-
-/* This is the function that does the actual writing of data.  If you are
- * not writing to a standard C stream, you should create a replacement
- * write_data function and use it at run time with png_set_write_fn(), rather
- * than changing the library.
- */
-#ifndef USE_FAR_KEYWORD
-static void PNGCBAPI
-pngtest_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_size_t check;
-
-   check = fwrite(data, 1, length, (png_FILE_p)png_get_io_ptr(png_ptr));
-
-   if (check != length)
-   {
-      png_error(png_ptr, "Write Error");
-   }
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   pngtest_check_io_state(png_ptr, length, PNG_IO_WRITING);
-#endif
-}
-#else
-/* This is the model-independent version. Since the standard I/O library
-   can't handle far buffers in the medium and small models, we have to copy
-   the data.
-*/
-
-#define NEAR_BUF_SIZE 1024
-#define MIN(a,b) (a <= b ? a : b)
-
-static void PNGCBAPI
-pngtest_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_size_t check;
-   png_byte *near_data;  /* Needs to be "png_byte *" instead of "png_bytep" */
-   png_FILE_p io_ptr;
-
-   /* Check if data really is near. If so, use usual code. */
-   near_data = (png_byte *)CVT_PTR_NOCHECK(data);
-   io_ptr = (png_FILE_p)CVT_PTR(png_get_io_ptr(png_ptr));
-
-   if ((png_bytep)near_data == data)
-   {
-      check = fwrite(near_data, 1, length, io_ptr);
-   }
-
-   else
-   {
-      png_byte buf[NEAR_BUF_SIZE];
-      png_size_t written, remaining, err;
-      check = 0;
-      remaining = length;
-
-      do
-      {
-         written = MIN(NEAR_BUF_SIZE, remaining);
-         png_memcpy(buf, data, written); /* Copy far buffer to near buffer */
-         err = fwrite(buf, 1, written, io_ptr);
-         if (err != written)
-            break;
-         else
-            check += err;
-         data += written;
-         remaining -= written;
-      }
-      while (remaining != 0);
-   }
-
-   if (check != length)
-   {
-      png_error(png_ptr, "Write Error");
-   }
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   pngtest_check_io_state(png_ptr, length, PNG_IO_WRITING);
-#endif
-}
-#endif /* USE_FAR_KEYWORD */
-
-/* This function is called when there is a warning, but the library thinks
- * it can continue anyway.  Replacement functions don't have to do anything
- * here if you don't want to.  In the default configuration, png_ptr is
- * not used, but it is passed in case it may be useful.
- */
-static void PNGCBAPI
-pngtest_warning(png_structp png_ptr, png_const_charp message)
-{
-   PNG_CONST char *name = "UNKNOWN (ERROR!)";
-   char *test;
-   test = png_get_error_ptr(png_ptr);
-
-   if (test == NULL)
-     fprintf(STDERR, "%s: libpng warning: %s\n", name, message);
-
-   else
-     fprintf(STDERR, "%s: libpng warning: %s\n", test, message);
-}
-
-/* This is the default error handling function.  Note that replacements for
- * this function MUST NOT RETURN, or the program will likely crash.  This
- * function is used by default, or if the program supplies NULL for the
- * error function pointer in png_set_error_fn().
- */
-static void PNGCBAPI
-pngtest_error(png_structp png_ptr, png_const_charp message)
-{
-   pngtest_warning(png_ptr, message);
-   /* We can return because png_error calls the default handler, which is
-    * actually OK in this case.
-    */
-}
-#endif /* !PNG_STDIO_SUPPORTED */
-/* END of code to validate stdio-free compilation */
-
-/* START of code to validate memory allocation and deallocation */
-#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-
-/* Allocate memory.  For reasonable files, size should never exceed
- * 64K.  However, zlib may allocate more then 64K if you don't tell
- * it not to.  See zconf.h and png.h for more information.  zlib does
- * need to allocate exactly 64K, so whatever you call here must
- * have the ability to do that.
- *
- * This piece of code can be compiled to validate max 64K allocations
- * by setting MAXSEG_64K in zlib zconf.h *or* PNG_MAX_MALLOC_64K.
- */
-typedef struct memory_information
-{
-   png_alloc_size_t          size;
-   png_voidp                 pointer;
-   struct memory_information FAR *next;
-} memory_information;
-typedef memory_information FAR *memory_infop;
-
-static memory_infop pinformation = NULL;
-static int current_allocation = 0;
-static int maximum_allocation = 0;
-static int total_allocation = 0;
-static int num_allocations = 0;
-
-png_voidp PNGCBAPI png_debug_malloc PNGARG((png_structp png_ptr,
-    png_alloc_size_t size));
-void PNGCBAPI png_debug_free PNGARG((png_structp png_ptr, png_voidp ptr));
-
-png_voidp
-PNGCBAPI png_debug_malloc(png_structp png_ptr, png_alloc_size_t size)
-{
-
-   /* png_malloc has already tested for NULL; png_create_struct calls
-    * png_debug_malloc directly, with png_ptr == NULL which is OK
-    */
-
-   if (size == 0)
-      return (NULL);
-
-   /* This calls the library allocator twice, once to get the requested
-      buffer and once to get a new free list entry. */
-   {
-      /* Disable malloc_fn and free_fn */
-      memory_infop pinfo;
-      png_set_mem_fn(png_ptr, NULL, NULL, NULL);
-      pinfo = (memory_infop)png_malloc(png_ptr,
-         png_sizeof(*pinfo));
-      pinfo->size = size;
-      current_allocation += size;
-      total_allocation += size;
-      num_allocations ++;
-
-      if (current_allocation > maximum_allocation)
-         maximum_allocation = current_allocation;
-
-      pinfo->pointer = png_malloc(png_ptr, size);
-      /* Restore malloc_fn and free_fn */
-
-      png_set_mem_fn(png_ptr,
-          NULL, png_debug_malloc, png_debug_free);
-
-      if (size != 0 && pinfo->pointer == NULL)
-      {
-         current_allocation -= size;
-         total_allocation -= size;
-         png_error(png_ptr,
-           "out of memory in pngtest->png_debug_malloc");
-      }
-
-      pinfo->next = pinformation;
-      pinformation = pinfo;
-      /* Make sure the caller isn't assuming zeroed memory. */
-      png_memset(pinfo->pointer, 0xdd, pinfo->size);
-
-      if (verbose)
-         printf("png_malloc %lu bytes at %p\n", (unsigned long)size,
-            pinfo->pointer);
-
-      return (png_voidp)(pinfo->pointer);
-   }
-}
-
-/* Free a pointer.  It is removed from the list at the same time. */
-void PNGCBAPI
-png_debug_free(png_structp png_ptr, png_voidp ptr)
-{
-   if (png_ptr == NULL)
-      fprintf(STDERR, "NULL pointer to png_debug_free.\n");
-
-   if (ptr == 0)
-   {
-#if 0 /* This happens all the time. */
-      fprintf(STDERR, "WARNING: freeing NULL pointer\n");
-#endif
-      return;
-   }
-
-   /* Unlink the element from the list. */
-   {
-      memory_infop FAR *ppinfo = &pinformation;
-
-      for (;;)
-      {
-         memory_infop pinfo = *ppinfo;
-
-         if (pinfo->pointer == ptr)
-         {
-            *ppinfo = pinfo->next;
-            current_allocation -= pinfo->size;
-            if (current_allocation < 0)
-               fprintf(STDERR, "Duplicate free of memory\n");
-            /* We must free the list element too, but first kill
-               the memory that is to be freed. */
-            png_memset(ptr, 0x55, pinfo->size);
-            png_free_default(png_ptr, pinfo);
-            pinfo = NULL;
-            break;
-         }
-
-         if (pinfo->next == NULL)
-         {
-            fprintf(STDERR, "Pointer %x not found\n", (unsigned int)ptr);
-            break;
-         }
-
-         ppinfo = &pinfo->next;
-      }
-   }
-
-   /* Finally free the data. */
-   if (verbose)
-      printf("Freeing %p\n", ptr);
-
-   png_free_default(png_ptr, ptr);
-   ptr = NULL;
-}
-#endif /* PNG_USER_MEM_SUPPORTED && PNG_DEBUG */
-/* END of code to test memory allocation/deallocation */
-
-
-/* Demonstration of user chunk support of the sTER and vpAg chunks */
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-
-/* (sTER is a public chunk not yet known by libpng.  vpAg is a private
-chunk used in ImageMagick to store "virtual page" size).  */
-
-static png_uint_32 user_chunk_data[4];
-
-    /* 0: sTER mode + 1
-     * 1: vpAg width
-     * 2: vpAg height
-     * 3: vpAg units
-     */
-
-static int PNGCBAPI read_user_chunk_callback(png_struct *png_ptr,
-   png_unknown_chunkp chunk)
-{
-   png_uint_32
-     *my_user_chunk_data;
-
-   /* Return one of the following:
-    *    return (-n);  chunk had an error
-    *    return (0);  did not recognize
-    *    return (n);  success
-    *
-    * The unknown chunk structure contains the chunk data:
-    * png_byte name[5];
-    * png_byte *data;
-    * png_size_t size;
-    *
-    * Note that libpng has already taken care of the CRC handling.
-    */
-
-   if (chunk->name[0] == 115 && chunk->name[1] ==  84 &&     /* s  T */
-       chunk->name[2] ==  69 && chunk->name[3] ==  82)       /* E  R */
-      {
-         /* Found sTER chunk */
-         if (chunk->size != 1)
-            return (-1); /* Error return */
-
-         if (chunk->data[0] != 0 && chunk->data[0] != 1)
-            return (-1);  /* Invalid mode */
-
-         my_user_chunk_data=(png_uint_32 *) png_get_user_chunk_ptr(png_ptr);
-         my_user_chunk_data[0]=chunk->data[0]+1;
-         return (1);
-      }
-
-   if (chunk->name[0] != 118 || chunk->name[1] != 112 ||    /* v  p */
-       chunk->name[2] !=  65 || chunk->name[3] != 103)      /* A  g */
-      return (0); /* Did not recognize */
-
-   /* Found ImageMagick vpAg chunk */
-
-   if (chunk->size != 9)
-      return (-1); /* Error return */
-
-   my_user_chunk_data=(png_uint_32 *) png_get_user_chunk_ptr(png_ptr);
-
-   my_user_chunk_data[1]=png_get_uint_31(png_ptr, chunk->data);
-   my_user_chunk_data[2]=png_get_uint_31(png_ptr, chunk->data + 4);
-   my_user_chunk_data[3]=(png_uint_32)chunk->data[8];
-
-   return (1);
-
-}
-#endif
-/* END of code to demonstrate user chunk support */
-
-/* Test one file */
-int
-test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
-{
-   static png_FILE_p fpin;
-   static png_FILE_p fpout;  /* "static" prevents setjmp corruption */
-   png_structp read_ptr;
-   png_infop read_info_ptr, end_info_ptr;
-#ifdef PNG_WRITE_SUPPORTED
-   png_structp write_ptr;
-   png_infop write_info_ptr;
-   png_infop write_end_info_ptr;
-#else
-   png_structp write_ptr = NULL;
-   png_infop write_info_ptr = NULL;
-   png_infop write_end_info_ptr = NULL;
-#endif
-   png_bytep row_buf;
-   png_uint_32 y;
-   png_uint_32 width, height;
-   int num_pass, pass;
-   int bit_depth, color_type;
-#ifdef PNG_SETJMP_SUPPORTED
-#ifdef USE_FAR_KEYWORD
-   jmp_buf tmp_jmpbuf;
-#endif
-#endif
-
-   char inbuf[256], outbuf[256];
-
-   row_buf = NULL;
-
-   if ((fpin = fopen(inname, "rb")) == NULL)
-   {
-      fprintf(STDERR, "Could not find input file %s\n", inname);
-      return (1);
-   }
-
-   if ((fpout = fopen(outname, "wb")) == NULL)
-   {
-      fprintf(STDERR, "Could not open output file %s\n", outname);
-      FCLOSE(fpin);
-      return (1);
-   }
-
-   pngtest_debug("Allocating read and write structures");
-#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-   read_ptr =
-      png_create_read_struct_2(PNG_LIBPNG_VER_STRING, NULL,
-      NULL, NULL, NULL, png_debug_malloc, png_debug_free);
-#else
-   read_ptr =
-      png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-#endif
-#ifndef PNG_STDIO_SUPPORTED
-   png_set_error_fn(read_ptr, (png_voidp)inname, pngtest_error,
-       pngtest_warning);
-#endif
-
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-   user_chunk_data[0] = 0;
-   user_chunk_data[1] = 0;
-   user_chunk_data[2] = 0;
-   user_chunk_data[3] = 0;
-   png_set_read_user_chunk_fn(read_ptr, user_chunk_data,
-     read_user_chunk_callback);
-
-#endif
-#ifdef PNG_WRITE_SUPPORTED
-#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-   write_ptr =
-      png_create_write_struct_2(PNG_LIBPNG_VER_STRING, NULL,
-      NULL, NULL, NULL, png_debug_malloc, png_debug_free);
-#else
-   write_ptr =
-      png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-#endif
-#ifndef PNG_STDIO_SUPPORTED
-   png_set_error_fn(write_ptr, (png_voidp)inname, pngtest_error,
-       pngtest_warning);
-#endif
-#endif
-   pngtest_debug("Allocating read_info, write_info and end_info structures");
-   read_info_ptr = png_create_info_struct(read_ptr);
-   end_info_ptr = png_create_info_struct(read_ptr);
-#ifdef PNG_WRITE_SUPPORTED
-   write_info_ptr = png_create_info_struct(write_ptr);
-   write_end_info_ptr = png_create_info_struct(write_ptr);
-#endif
-
-#ifdef PNG_SETJMP_SUPPORTED
-   pngtest_debug("Setting jmpbuf for read struct");
-#ifdef USE_FAR_KEYWORD
-   if (setjmp(tmp_jmpbuf))
-#else
-   if (setjmp(png_jmpbuf(read_ptr)))
-#endif
-   {
-      fprintf(STDERR, "%s -> %s: libpng read error\n", inname, outname);
-      png_free(read_ptr, row_buf);
-      row_buf = NULL;
-      png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
-#ifdef PNG_WRITE_SUPPORTED
-      png_destroy_info_struct(write_ptr, &write_end_info_ptr);
-      png_destroy_write_struct(&write_ptr, &write_info_ptr);
-#endif
-      FCLOSE(fpin);
-      FCLOSE(fpout);
-      return (1);
-   }
-#ifdef USE_FAR_KEYWORD
-   png_memcpy(png_jmpbuf(read_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
-#endif
-
-#ifdef PNG_WRITE_SUPPORTED
-   pngtest_debug("Setting jmpbuf for write struct");
-#ifdef USE_FAR_KEYWORD
-
-   if (setjmp(tmp_jmpbuf))
-#else
-   if (setjmp(png_jmpbuf(write_ptr)))
-#endif
-   {
-      fprintf(STDERR, "%s -> %s: libpng write error\n", inname, outname);
-      png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
-      png_destroy_info_struct(write_ptr, &write_end_info_ptr);
-#ifdef PNG_WRITE_SUPPORTED
-      png_destroy_write_struct(&write_ptr, &write_info_ptr);
-#endif
-      FCLOSE(fpin);
-      FCLOSE(fpout);
-      return (1);
-   }
-
-#ifdef USE_FAR_KEYWORD
-   png_memcpy(png_jmpbuf(write_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
-#endif
-#endif
-#endif
-
-   pngtest_debug("Initializing input and output streams");
-#ifdef PNG_STDIO_SUPPORTED
-   png_init_io(read_ptr, fpin);
-#  ifdef PNG_WRITE_SUPPORTED
-   png_init_io(write_ptr, fpout);
-#  endif
-#else
-   png_set_read_fn(read_ptr, (png_voidp)fpin, pngtest_read_data);
-#  ifdef PNG_WRITE_SUPPORTED
-   png_set_write_fn(write_ptr, (png_voidp)fpout,  pngtest_write_data,
-#    ifdef PNG_WRITE_FLUSH_SUPPORTED
-      pngtest_flush);
-#    else
-      NULL);
-#    endif
-#  endif
-#endif
-
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
-   /* Normally one would use Z_DEFAULT_STRATEGY for text compression.
-    * This is here just to make pngtest replicate the results from libpng
-    * versions prior to 1.5.4, and to test this new API.
-    */
-   png_set_text_compression_strategy(write_ptr, Z_FILTERED);
-#endif
-
-   if (status_dots_requested == 1)
-   {
-#ifdef PNG_WRITE_SUPPORTED
-      png_set_write_status_fn(write_ptr, write_row_callback);
-#endif
-      png_set_read_status_fn(read_ptr, read_row_callback);
-   }
-
-   else
-   {
-#ifdef PNG_WRITE_SUPPORTED
-      png_set_write_status_fn(write_ptr, NULL);
-#endif
-      png_set_read_status_fn(read_ptr, NULL);
-   }
-
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-   {
-      int i;
-
-      for (i = 0; i<256; i++)
-         filters_used[i] = 0;
-
-      png_set_read_user_transform_fn(read_ptr, count_filters);
-   }
-#endif
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-   zero_samples = 0;
-   png_set_write_user_transform_fn(write_ptr, count_zero_samples);
-#endif
-
-#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
-#  ifndef PNG_HANDLE_CHUNK_ALWAYS
-#    define PNG_HANDLE_CHUNK_ALWAYS       3
-#  endif
-   png_set_keep_unknown_chunks(read_ptr, PNG_HANDLE_CHUNK_ALWAYS,
-      NULL, 0);
-#endif
-#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-#  ifndef PNG_HANDLE_CHUNK_IF_SAFE
-#    define PNG_HANDLE_CHUNK_IF_SAFE      2
-#  endif
-   png_set_keep_unknown_chunks(write_ptr, PNG_HANDLE_CHUNK_IF_SAFE,
-      NULL, 0);
-#endif
-
-   pngtest_debug("Reading info struct");
-   png_read_info(read_ptr, read_info_ptr);
-
-   pngtest_debug("Transferring info struct");
-   {
-      int interlace_type, compression_type, filter_type;
-
-      if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth,
-          &color_type, &interlace_type, &compression_type, &filter_type))
-      {
-         png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-            color_type, interlace_type, compression_type, filter_type);
-#else
-            color_type, PNG_INTERLACE_NONE, compression_type, filter_type);
-#endif
-      }
-   }
-#ifdef PNG_FIXED_POINT_SUPPORTED
-#ifdef PNG_cHRM_SUPPORTED
-   {
-      png_fixed_point white_x, white_y, red_x, red_y, green_x, green_y, blue_x,
-         blue_y;
-
-      if (png_get_cHRM_fixed(read_ptr, read_info_ptr, &white_x, &white_y,
-         &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y))
-      {
-         png_set_cHRM_fixed(write_ptr, write_info_ptr, white_x, white_y, red_x,
-            red_y, green_x, green_y, blue_x, blue_y);
-      }
-   }
-#endif
-#ifdef PNG_gAMA_SUPPORTED
-   {
-      png_fixed_point gamma;
-
-      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma))
-         png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma);
-   }
-#endif
-#else /* Use floating point versions */
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-#ifdef PNG_cHRM_SUPPORTED
-   {
-      double white_x, white_y, red_x, red_y, green_x, green_y, blue_x,
-         blue_y;
-
-      if (png_get_cHRM(read_ptr, read_info_ptr, &white_x, &white_y, &red_x,
-         &red_y, &green_x, &green_y, &blue_x, &blue_y))
-      {
-         png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x,
-            red_y, green_x, green_y, blue_x, blue_y);
-      }
-   }
-#endif
-#ifdef PNG_gAMA_SUPPORTED
-   {
-      double gamma;
-
-      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma))
-         png_set_gAMA(write_ptr, write_info_ptr, gamma);
-   }
-#endif
-#endif /* Floating point */
-#endif /* Fixed point */
-#ifdef PNG_iCCP_SUPPORTED
-   {
-      png_charp name;
-      png_bytep profile;
-      png_uint_32 proflen;
-      int compression_type;
-
-      if (png_get_iCCP(read_ptr, read_info_ptr, &name, &compression_type,
-                      &profile, &proflen))
-      {
-         png_set_iCCP(write_ptr, write_info_ptr, name, compression_type,
-                      profile, proflen);
-      }
-   }
-#endif
-#ifdef PNG_sRGB_SUPPORTED
-   {
-      int intent;
-
-      if (png_get_sRGB(read_ptr, read_info_ptr, &intent))
-         png_set_sRGB(write_ptr, write_info_ptr, intent);
-   }
-#endif
-   {
-      png_colorp palette;
-      int num_palette;
-
-      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette))
-         png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette);
-   }
-#ifdef PNG_bKGD_SUPPORTED
-   {
-      png_color_16p background;
-
-      if (png_get_bKGD(read_ptr, read_info_ptr, &background))
-      {
-         png_set_bKGD(write_ptr, write_info_ptr, background);
-      }
-   }
-#endif
-#ifdef PNG_hIST_SUPPORTED
-   {
-      png_uint_16p hist;
-
-      if (png_get_hIST(read_ptr, read_info_ptr, &hist))
-         png_set_hIST(write_ptr, write_info_ptr, hist);
-   }
-#endif
-#ifdef PNG_oFFs_SUPPORTED
-   {
-      png_int_32 offset_x, offset_y;
-      int unit_type;
-
-      if (png_get_oFFs(read_ptr, read_info_ptr, &offset_x, &offset_y,
-          &unit_type))
-      {
-         png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);
-      }
-   }
-#endif
-#ifdef PNG_pCAL_SUPPORTED
-   {
-      png_charp purpose, units;
-      png_charpp params;
-      png_int_32 X0, X1;
-      int type, nparams;
-
-      if (png_get_pCAL(read_ptr, read_info_ptr, &purpose, &X0, &X1, &type,
-         &nparams, &units, &params))
-      {
-         png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type,
-            nparams, units, params);
-      }
-   }
-#endif
-#ifdef PNG_pHYs_SUPPORTED
-   {
-      png_uint_32 res_x, res_y;
-      int unit_type;
-
-      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y, &unit_type))
-         png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);
-   }
-#endif
-#ifdef PNG_sBIT_SUPPORTED
-   {
-      png_color_8p sig_bit;
-
-      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit))
-         png_set_sBIT(write_ptr, write_info_ptr, sig_bit);
-   }
-#endif
-#ifdef PNG_sCAL_SUPPORTED
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-   {
-      int unit;
-      double scal_width, scal_height;
-
-      if (png_get_sCAL(read_ptr, read_info_ptr, &unit, &scal_width,
-         &scal_height))
-      {
-         png_set_sCAL(write_ptr, write_info_ptr, unit, scal_width, scal_height);
-      }
-   }
-#else
-#ifdef PNG_FIXED_POINT_SUPPORTED
-   {
-      int unit;
-      png_charp scal_width, scal_height;
-
-      if (png_get_sCAL_s(read_ptr, read_info_ptr, &unit, &scal_width,
-          &scal_height))
-      {
-         png_set_sCAL_s(write_ptr, write_info_ptr, unit, scal_width,
-             scal_height);
-      }
-   }
-#endif
-#endif
-#endif
-#ifdef PNG_TEXT_SUPPORTED
-   {
-      png_textp text_ptr;
-      int num_text;
-
-      if (png_get_text(read_ptr, read_info_ptr, &text_ptr, &num_text) > 0)
-      {
-         pngtest_debug1("Handling %d iTXt/tEXt/zTXt chunks", num_text);
-
-         if (verbose)
-            printf("\n Text compression=%d\n", text_ptr->compression);
-
-         png_set_text(write_ptr, write_info_ptr, text_ptr, num_text);
-      }
-   }
-#endif
-#ifdef PNG_tIME_SUPPORTED
-   {
-      png_timep mod_time;
-
-      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time))
-      {
-         png_set_tIME(write_ptr, write_info_ptr, mod_time);
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-         /* We have to use png_memcpy instead of "=" because the string
-          * pointed to by png_convert_to_rfc1123() gets free'ed before
-          * we use it.
-          */
-         png_memcpy(tIME_string,
-                    png_convert_to_rfc1123(read_ptr, mod_time),
-                    png_sizeof(tIME_string));
-
-         tIME_string[png_sizeof(tIME_string) - 1] = '\0';
-         tIME_chunk_present++;
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
-      }
-   }
-#endif
-#ifdef PNG_tRNS_SUPPORTED
-   {
-      png_bytep trans_alpha;
-      int num_trans;
-      png_color_16p trans_color;
-
-      if (png_get_tRNS(read_ptr, read_info_ptr, &trans_alpha, &num_trans,
-         &trans_color))
-      {
-         int sample_max = (1 << bit_depth);
-         /* libpng doesn't reject a tRNS chunk with out-of-range samples */
-         if (!((color_type == PNG_COLOR_TYPE_GRAY &&
-             (int)trans_color->gray > sample_max) ||
-             (color_type == PNG_COLOR_TYPE_RGB &&
-             ((int)trans_color->red > sample_max ||
-             (int)trans_color->green > sample_max ||
-             (int)trans_color->blue > sample_max))))
-            png_set_tRNS(write_ptr, write_info_ptr, trans_alpha, num_trans,
-               trans_color);
-      }
-   }
-#endif
-#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-   {
-      png_unknown_chunkp unknowns;
-      int num_unknowns = png_get_unknown_chunks(read_ptr, read_info_ptr,
-         &unknowns);
-
-      if (num_unknowns)
-      {
-         int i;
-         png_set_unknown_chunks(write_ptr, write_info_ptr, unknowns,
-           num_unknowns);
-         /* Copy the locations from the read_info_ptr.  The automatically
-          * generated locations in write_info_ptr are wrong because we
-          * haven't written anything yet.
-          */
-         for (i = 0; i < num_unknowns; i++)
-           png_set_unknown_chunk_location(write_ptr, write_info_ptr, i,
-             unknowns[i].location);
-      }
-   }
-#endif
-
-#ifdef PNG_WRITE_SUPPORTED
-   pngtest_debug("Writing info struct");
-
-/* If we wanted, we could write info in two steps:
- * png_write_info_before_PLTE(write_ptr, write_info_ptr);
- */
-   png_write_info(write_ptr, write_info_ptr);
-
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-   if (user_chunk_data[0] != 0)
-   {
-      png_byte png_sTER[5] = {115,  84,  69,  82, '\0'};
-
-      unsigned char
-        ster_chunk_data[1];
-
-      if (verbose)
-         fprintf(STDERR, "\n stereo mode = %lu\n",
-           (unsigned long)(user_chunk_data[0] - 1));
-
-      ster_chunk_data[0]=(unsigned char)(user_chunk_data[0] - 1);
-      png_write_chunk(write_ptr, png_sTER, ster_chunk_data, 1);
-   }
-
-   if (user_chunk_data[1] != 0 || user_chunk_data[2] != 0)
-   {
-      png_byte png_vpAg[5] = {118, 112,  65, 103, '\0'};
-
-      unsigned char
-        vpag_chunk_data[9];
-
-      if (verbose)
-         fprintf(STDERR, " vpAg = %lu x %lu, units = %lu\n",
-           (unsigned long)user_chunk_data[1],
-           (unsigned long)user_chunk_data[2],
-           (unsigned long)user_chunk_data[3]);
-
-      png_save_uint_32(vpag_chunk_data, user_chunk_data[1]);
-      png_save_uint_32(vpag_chunk_data + 4, user_chunk_data[2]);
-      vpag_chunk_data[8] = (unsigned char)(user_chunk_data[3] & 0xff);
-      png_write_chunk(write_ptr, png_vpAg, vpag_chunk_data, 9);
-   }
-
-#endif
-#endif
-
-#ifdef SINGLE_ROWBUF_ALLOC
-   pngtest_debug("Allocating row buffer...");
-   row_buf = (png_bytep)png_malloc(read_ptr,
-      png_get_rowbytes(read_ptr, read_info_ptr));
-
-   pngtest_debug1("\t0x%08lx", (unsigned long)row_buf);
-#endif /* SINGLE_ROWBUF_ALLOC */
-   pngtest_debug("Writing row data");
-
-#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
-  defined(PNG_WRITE_INTERLACING_SUPPORTED)
-   num_pass = png_set_interlace_handling(read_ptr);
-#  ifdef PNG_WRITE_SUPPORTED
-   png_set_interlace_handling(write_ptr);
-#  endif
-#else
-   num_pass = 1;
-#endif
-
-#ifdef PNGTEST_TIMING
-   t_stop = (float)clock();
-   t_misc += (t_stop - t_start);
-   t_start = t_stop;
-#endif
-   for (pass = 0; pass < num_pass; pass++)
-   {
-      pngtest_debug1("Writing row data for pass %d", pass);
-      for (y = 0; y < height; y++)
-      {
-#ifndef SINGLE_ROWBUF_ALLOC
-         pngtest_debug2("Allocating row buffer (pass %d, y = %u)...", pass, y);
-         row_buf = (png_bytep)png_malloc(read_ptr,
-            png_get_rowbytes(read_ptr, read_info_ptr));
-
-         pngtest_debug2("\t0x%08lx (%u bytes)", (unsigned long)row_buf,
-            png_get_rowbytes(read_ptr, read_info_ptr));
-
-#endif /* !SINGLE_ROWBUF_ALLOC */
-         png_read_rows(read_ptr, (png_bytepp)&row_buf, NULL, 1);
-
-#ifdef PNG_WRITE_SUPPORTED
-#ifdef PNGTEST_TIMING
-         t_stop = (float)clock();
-         t_decode += (t_stop - t_start);
-         t_start = t_stop;
-#endif
-         png_write_rows(write_ptr, (png_bytepp)&row_buf, 1);
-#ifdef PNGTEST_TIMING
-         t_stop = (float)clock();
-         t_encode += (t_stop - t_start);
-         t_start = t_stop;
-#endif
-#endif /* PNG_WRITE_SUPPORTED */
-
-#ifndef SINGLE_ROWBUF_ALLOC
-         pngtest_debug2("Freeing row buffer (pass %d, y = %u)", pass, y);
-         png_free(read_ptr, row_buf);
-         row_buf = NULL;
-#endif /* !SINGLE_ROWBUF_ALLOC */
-      }
-   }
-
-#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
-   png_free_data(read_ptr, read_info_ptr, PNG_FREE_UNKN, -1);
-#endif
-#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-   png_free_data(write_ptr, write_info_ptr, PNG_FREE_UNKN, -1);
-#endif
-
-   pngtest_debug("Reading and writing end_info data");
-
-   png_read_end(read_ptr, end_info_ptr);
-#ifdef PNG_TEXT_SUPPORTED
-   {
-      png_textp text_ptr;
-      int num_text;
-
-      if (png_get_text(read_ptr, end_info_ptr, &text_ptr, &num_text) > 0)
-      {
-         pngtest_debug1("Handling %d iTXt/tEXt/zTXt chunks", num_text);
-         png_set_text(write_ptr, write_end_info_ptr, text_ptr, num_text);
-      }
-   }
-#endif
-#ifdef PNG_tIME_SUPPORTED
-   {
-      png_timep mod_time;
-
-      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time))
-      {
-         png_set_tIME(write_ptr, write_end_info_ptr, mod_time);
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-         /* We have to use png_memcpy instead of "=" because the string
-            pointed to by png_convert_to_rfc1123() gets free'ed before
-            we use it */
-         png_memcpy(tIME_string,
-                    png_convert_to_rfc1123(read_ptr, mod_time),
-                    png_sizeof(tIME_string));
-
-         tIME_string[png_sizeof(tIME_string) - 1] = '\0';
-         tIME_chunk_present++;
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
-      }
-   }
-#endif
-#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-   {
-      png_unknown_chunkp unknowns;
-      int num_unknowns = png_get_unknown_chunks(read_ptr, end_info_ptr,
-         &unknowns);
-
-      if (num_unknowns)
-      {
-         int i;
-         png_set_unknown_chunks(write_ptr, write_end_info_ptr, unknowns,
-           num_unknowns);
-         /* Copy the locations from the read_info_ptr.  The automatically
-          * generated locations in write_end_info_ptr are wrong because we
-          * haven't written the end_info yet.
-          */
-         for (i = 0; i < num_unknowns; i++)
-           png_set_unknown_chunk_location(write_ptr, write_end_info_ptr, i,
-             unknowns[i].location);
-      }
-   }
-#endif
-#ifdef PNG_WRITE_SUPPORTED
-   png_write_end(write_ptr, write_end_info_ptr);
-#endif
-
-#ifdef PNG_EASY_ACCESS_SUPPORTED
-   if (verbose)
-   {
-      png_uint_32 iwidth, iheight;
-      iwidth = png_get_image_width(write_ptr, write_info_ptr);
-      iheight = png_get_image_height(write_ptr, write_info_ptr);
-      fprintf(STDERR, "\n Image width = %lu, height = %lu\n",
-         (unsigned long)iwidth, (unsigned long)iheight);
-   }
-#endif
-
-   pngtest_debug("Destroying data structs");
-#ifdef SINGLE_ROWBUF_ALLOC
-   pngtest_debug("destroying row_buf for read_ptr");
-   png_free(read_ptr, row_buf);
-   row_buf = NULL;
-#endif /* SINGLE_ROWBUF_ALLOC */
-   pngtest_debug("destroying read_ptr, read_info_ptr, end_info_ptr");
-   png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
-#ifdef PNG_WRITE_SUPPORTED
-   pngtest_debug("destroying write_end_info_ptr");
-   png_destroy_info_struct(write_ptr, &write_end_info_ptr);
-   pngtest_debug("destroying write_ptr, write_info_ptr");
-   png_destroy_write_struct(&write_ptr, &write_info_ptr);
-#endif
-   pngtest_debug("Destruction complete.");
-
-   FCLOSE(fpin);
-   FCLOSE(fpout);
-
-   pngtest_debug("Opening files for comparison");
-   if ((fpin = fopen(inname, "rb")) == NULL)
-   {
-      fprintf(STDERR, "Could not find file %s\n", inname);
-      return (1);
-   }
-
-   if ((fpout = fopen(outname, "rb")) == NULL)
-   {
-      fprintf(STDERR, "Could not find file %s\n", outname);
-      FCLOSE(fpin);
-      return (1);
-   }
-
-   for (;;)
-   {
-      png_size_t num_in, num_out;
-
-         num_in = fread(inbuf, 1, 1, fpin);
-         num_out = fread(outbuf, 1, 1, fpout);
-
-      if (num_in != num_out)
-      {
-         fprintf(STDERR, "\nFiles %s and %s are of a different size\n",
-                 inname, outname);
-
-         if (wrote_question == 0)
-         {
-            fprintf(STDERR,
-         "   Was %s written with the same maximum IDAT chunk size (%d bytes),",
-              inname, PNG_ZBUF_SIZE);
-            fprintf(STDERR,
-              "\n   filtering heuristic (libpng default), compression");
-            fprintf(STDERR,
-              " level (zlib default),\n   and zlib version (%s)?\n\n",
-              ZLIB_VERSION);
-            wrote_question = 1;
-         }
-
-         FCLOSE(fpin);
-         FCLOSE(fpout);
-
-         if (strict != 0)
-           return (1);
-
-         else
-           return (0);
-      }
-
-      if (!num_in)
-         break;
-
-      if (png_memcmp(inbuf, outbuf, num_in))
-      {
-         fprintf(STDERR, "\nFiles %s and %s are different\n", inname, outname);
-
-         if (wrote_question == 0)
-         {
-            fprintf(STDERR,
-         "   Was %s written with the same maximum IDAT chunk size (%d bytes),",
-                 inname, PNG_ZBUF_SIZE);
-            fprintf(STDERR,
-              "\n   filtering heuristic (libpng default), compression");
-            fprintf(STDERR,
-              " level (zlib default),\n   and zlib version (%s)?\n\n",
-              ZLIB_VERSION);
-            wrote_question = 1;
-         }
-
-         FCLOSE(fpin);
-         FCLOSE(fpout);
-
-         if (strict != 0)
-           return (1);
-
-         else
-           return (0);
-      }
-   }
-
-   FCLOSE(fpin);
-   FCLOSE(fpout);
-
-   return (0);
-}
-
-/* Input and output filenames */
-#ifdef RISCOS
-static PNG_CONST char *inname = "pngtest/png";
-static PNG_CONST char *outname = "pngout/png";
-#else
-static PNG_CONST char *inname = "pngtest.png";
-static PNG_CONST char *outname = "pngout.png";
-#endif
-
-int
-main(int argc, char *argv[])
-{
-   int multiple = 0;
-   int ierror = 0;
-
-   fprintf(STDERR, "\n Testing libpng version %s\n", PNG_LIBPNG_VER_STRING);
-   fprintf(STDERR, "   with zlib   version %s\n", ZLIB_VERSION);
-   fprintf(STDERR, "%s", png_get_copyright(NULL));
-   /* Show the version of libpng used in building the library */
-   fprintf(STDERR, " library (%lu):%s",
-      (unsigned long)png_access_version_number(),
-      png_get_header_version(NULL));
-
-   /* Show the version of libpng used in building the application */
-   fprintf(STDERR, " pngtest (%lu):%s", (unsigned long)PNG_LIBPNG_VER,
-      PNG_HEADER_VERSION_STRING);
-
-   /* Do some consistency checking on the memory allocation settings, I'm
-    * not sure this matters, but it is nice to know, the first of these
-    * tests should be impossible because of the way the macros are set
-    * in pngconf.h
-    */
-#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
-      fprintf(STDERR, " NOTE: Zlib compiled for max 64k, libpng not\n");
-#endif
-   /* I think the following can happen. */
-#if !defined(MAXSEG_64K) && defined(PNG_MAX_MALLOC_64K)
-      fprintf(STDERR, " NOTE: libpng compiled for max 64k, zlib not\n");
-#endif
-
-   if (strcmp(png_libpng_ver, PNG_LIBPNG_VER_STRING))
-   {
-      fprintf(STDERR,
-         "Warning: versions are different between png.h and png.c\n");
-      fprintf(STDERR, "  png.h version: %s\n", PNG_LIBPNG_VER_STRING);
-      fprintf(STDERR, "  png.c version: %s\n\n", png_libpng_ver);
-      ++ierror;
-   }
-
-   if (argc > 1)
-   {
-      if (strcmp(argv[1], "-m") == 0)
-      {
-         multiple = 1;
-         status_dots_requested = 0;
-      }
-
-      else if (strcmp(argv[1], "-mv") == 0 ||
-               strcmp(argv[1], "-vm") == 0 )
-      {
-         multiple = 1;
-         verbose = 1;
-         status_dots_requested = 1;
-      }
-
-      else if (strcmp(argv[1], "-v") == 0)
-      {
-         verbose = 1;
-         status_dots_requested = 1;
-         inname = argv[2];
-      }
-
-      else if (strcmp(argv[1], "--strict") == 0)
-      {
-         status_dots_requested = 0;
-         verbose = 1;
-         inname = argv[2];
-         strict++;
-      }
-
-      else
-      {
-         inname = argv[1];
-         status_dots_requested = 0;
-      }
-   }
-
-   if (!multiple && argc == 3 + verbose)
-     outname = argv[2 + verbose];
-
-   if ((!multiple && argc > 3 + verbose) || (multiple && argc < 2))
-   {
-     fprintf(STDERR,
-       "usage: %s [infile.png] [outfile.png]\n\t%s -m {infile.png}\n",
-        argv[0], argv[0]);
-     fprintf(STDERR,
-       "  reads/writes one PNG file (without -m) or multiple files (-m)\n");
-     fprintf(STDERR,
-       "  with -m %s is used as a temporary file\n", outname);
-     exit(1);
-   }
-
-   if (multiple)
-   {
-      int i;
-#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-      int allocation_now = current_allocation;
-#endif
-      for (i=2; i<argc; ++i)
-      {
-         int kerror;
-         fprintf(STDERR, "\n Testing %s:", argv[i]);
-         kerror = test_one_file(argv[i], outname);
-         if (kerror == 0)
-         {
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-            int k;
-#endif
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-            fprintf(STDERR, "\n PASS (%lu zero samples)\n",
-               (unsigned long)zero_samples);
-#else
-            fprintf(STDERR, " PASS\n");
-#endif
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-            for (k = 0; k<256; k++)
-               if (filters_used[k])
-                  fprintf(STDERR, " Filter %d was used %lu times\n",
-                     k, (unsigned long)filters_used[k]);
-#endif
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-         if (tIME_chunk_present != 0)
-            fprintf(STDERR, " tIME = %s\n", tIME_string);
-
-         tIME_chunk_present = 0;
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
-         }
-
-         else
-         {
-            fprintf(STDERR, " FAIL\n");
-            ierror += kerror;
-         }
-#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-         if (allocation_now != current_allocation)
-            fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n",
-               current_allocation - allocation_now);
-
-         if (current_allocation != 0)
-         {
-            memory_infop pinfo = pinformation;
-
-            fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n",
-               current_allocation);
-
-            while (pinfo != NULL)
-            {
-               fprintf(STDERR, " %lu bytes at %x\n",
-                 (unsigned long)pinfo->size,
-                 (unsigned int)pinfo->pointer);
-               pinfo = pinfo->next;
-            }
-         }
-#endif
-      }
-#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-         fprintf(STDERR, " Current memory allocation: %10d bytes\n",
-            current_allocation);
-         fprintf(STDERR, " Maximum memory allocation: %10d bytes\n",
-            maximum_allocation);
-         fprintf(STDERR, " Total   memory allocation: %10d bytes\n",
-            total_allocation);
-         fprintf(STDERR, "     Number of allocations: %10d\n",
-            num_allocations);
-#endif
-   }
-
-   else
-   {
-      int i;
-      for (i = 0; i<3; ++i)
-      {
-         int kerror;
-#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-         int allocation_now = current_allocation;
-#endif
-         if (i == 1)
-            status_dots_requested = 1;
-
-         else if (verbose == 0)
-            status_dots_requested = 0;
-
-         if (i == 0 || verbose == 1 || ierror != 0)
-            fprintf(STDERR, "\n Testing %s:", inname);
-
-         kerror = test_one_file(inname, outname);
-
-         if (kerror == 0)
-         {
-            if (verbose == 1 || i == 2)
-            {
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-                int k;
-#endif
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-                fprintf(STDERR, "\n PASS (%lu zero samples)\n",
-                   (unsigned long)zero_samples);
-#else
-                fprintf(STDERR, " PASS\n");
-#endif
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-                for (k = 0; k<256; k++)
-                   if (filters_used[k])
-                      fprintf(STDERR, " Filter %d was used %lu times\n",
-                         k, (unsigned long)filters_used[k]);
-#endif
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-             if (tIME_chunk_present != 0)
-                fprintf(STDERR, " tIME = %s\n", tIME_string);
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
-            }
-         }
-
-         else
-         {
-            if (verbose == 0 && i != 2)
-               fprintf(STDERR, "\n Testing %s:", inname);
-
-            fprintf(STDERR, " FAIL\n");
-            ierror += kerror;
-         }
-#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-         if (allocation_now != current_allocation)
-             fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n",
-               current_allocation - allocation_now);
-
-         if (current_allocation != 0)
-         {
-             memory_infop pinfo = pinformation;
-
-             fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n",
-                current_allocation);
-
-             while (pinfo != NULL)
-             {
-                fprintf(STDERR, " %lu bytes at %x\n",
-                   (unsigned long)pinfo->size, (unsigned int)pinfo->pointer);
-                pinfo = pinfo->next;
-             }
-          }
-#endif
-       }
-#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-       fprintf(STDERR, " Current memory allocation: %10d bytes\n",
-          current_allocation);
-       fprintf(STDERR, " Maximum memory allocation: %10d bytes\n",
-          maximum_allocation);
-       fprintf(STDERR, " Total   memory allocation: %10d bytes\n",
-          total_allocation);
-       fprintf(STDERR, "     Number of allocations: %10d\n",
-            num_allocations);
-#endif
-   }
-
-#ifdef PNGTEST_TIMING
-   t_stop = (float)clock();
-   t_misc += (t_stop - t_start);
-   t_start = t_stop;
-   fprintf(STDERR, " CPU time used = %.3f seconds",
-      (t_misc+t_decode+t_encode)/(float)CLOCKS_PER_SEC);
-   fprintf(STDERR, " (decoding %.3f,\n",
-      t_decode/(float)CLOCKS_PER_SEC);
-   fprintf(STDERR, "        encoding %.3f ,",
-      t_encode/(float)CLOCKS_PER_SEC);
-   fprintf(STDERR, " other %.3f seconds)\n\n",
-      t_misc/(float)CLOCKS_PER_SEC);
-#endif
-
-   if (ierror == 0)
-      fprintf(STDERR, " libpng passes test\n");
-
-   else
-      fprintf(STDERR, " libpng FAILS test\n");
-
-   return (int)(ierror != 0);
-}
-
-/* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_5_10 Your_png_h_is_not_version_1_5_10;
diff --git a/extern/libpng/include/pngtest.png b/extern/libpng/include/pngtest.png
deleted file mode 100644
index 81f5f8438a9f0fa8b87cd0266334f72792febf8f..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 8695
zcmV<TAqd`yP)<h;3K|Lk000e1NJLTq003J6002b@1^@s7Qthhb00004XF*Lt006O%
z3;baP00001b5ch_0olnce*gdg1am@3R0RbE1x=+b_5c6?AY({UO#lFTCIA3{ga82g
z0001h=l}q9FaQARU;qF*m;eA5aGbhPJOBUy24YJ`L;&Cb-~fP?%`YGT000SZMn-f0
z|Nr&?000yLy?X1E0000ia6>^%VsB@4b0BqYX>@Y{000000096000L%jZ!cnDasV+d
zFl8_RHZ?9aGc{#1S3r9l0000Ib3;K)0Wvc*HaA5rIWhn<F*GqYMK<Jr4YvRQ010qN
zS#tmY3ljhU3ljkVnw%H_000McNliru%mxP$ItY&cCVBt>010$OSaeirbZlh+P)<kO
z0eLk50004VR7Fw&wdA#&00009c5p#w0001F0001F0EZ@C<^TX6w@E}nRCt{2oKI+E
z$(`pvIg^6l0|_F)f)|D|#6S-`!5UHrL*{}Hx!?g6%pnD9sM?$6Fi?F{&8hpa1Ld3Q
z)^!-L=B7Frl!t-V!OP@f44JS7B}{|fp_dIqH^hS~cmbX8!jMhwAzr4WDphq=+wQS<
z{DViODl;SF{UYM`=llEq9{eF>SlHFikA^FNzj*b{^&1C0y8`&+Xt>IiFrGR9x&RM`
z#d+oH(XeM2U%ICv<N`eC7b~NL=d-c{kSpo`1;F!3d6+9rVGK&-_{qbeccC5w#F&2V
zpl4TAh_lU<LX4EICd;67o}=OZ$W=9Uj2JB_k?Sb|_}DOY6#zY}`0#Yn0jNHW$D@6F
z0`d0EJ{lIQ2g70o@X@HZN?*)JZ&ck{JKwGR>qn#2u*g>ce|htbC!_xPr2O(10B6Ss
zt9kjw&gU;*43^7`d`CX(+??~wd5YZd`1zzWJvmyPPcE61ZZ>ye0IeFU`dWp)cKqK@
zPgb+Z6k`PAb>H;#YFOmgItMUXxbihWdwM!<8b+aApr(PIHEEOOI-^}M_KfCqQXUTX
z3>S0P=@*7bWbVTC9go@_cz%5FMxFl!Kx}^w;PB~1=i93JokfJam#fi1&-(TMb>H@d
zyX2Fj;VJ@;+f90O&|5j@QIa7d#2cIS)+s$dK3IKnG+doLxZaB=NBz~=4LzMrudqr1
z=}`8KMkFJ|hAKqHGuOFu@Tv1muRLYt`Q&K0>KFOS`^a?e`1GSu`hiG=2sT$MYZaLY
zlesehO2MOp-s)f5&)yo`wCnHdhyWQdcY#Y^b2gcCc05|mUDcb;OZrw*RRJZ!LBH@y
zG(_+|+^rUXfi)N{TwFS=(O4rGm62t_(bKUxKR)or2+wD((=-r?6h_bjh0QTqD68=L
z;DymlT(W@D-o@#p><ssE(m+)ApI&r?41njevUB+KqVu!yywkG=qcbip-C%8zZpkM{
z!_}y7SC59hRnMvufP<brKY7q!y>0V<qbMQ&)?faUmIr-%0=I3)YrExrMTz7ejryxB
zljEadv0D3|_a1y$<fES-9juO8*8_0!aOg{)3~$pw72a_CUzJZD3|F5V4L63!`M}IM
z&L*V+IC(H!&Amqu>N-+|$l0`feej-DqbH;O>R&$^t&R_R=K$mR)r{tP7bz`+WSpoT
z^ox~bg7bkY)I`A7_4s0bhiy3;7Ux$!a5^a&_U!1<L9v>a)yNp($x(l;2J3y`LBCj4
zp=RGIO6QrBRp(;vI%O3O*Xp}9xNp+GSq82OhzO&8;Y(km$T%AIPUbEghS)H#JWWhC
z$c5M`a&^9rKF*I1R#R6^Zw+p;bfoJ#;(U#6SG|dmi%ZAxXmFhVhGAjZvzizq!y;c<
zqc^dH00Wy3ZVj%lcMw_$m#(4;5o<I`U|Kq^K6$j#Dx+r&brWfbh-3)K76~wSHP-0c
zgS)z!MIwQQp3!IoCCTiD2p>MXF!R!F;;0ZBLftSZk|kXKKodcUyfSzdru#PMqk{oY
zCnYY_tkqz&aCFe~AD>MJ_xCMEU{Y3{^O>VC8s9{$5p)Jf#46ptHTe0|oe1#Z^9i{K
z)@ZaAs-~%$CV6}p!pzt8#!Jpz)rk=v4hldJ5eC-q;qzp2Z-$kXkYSbHEKJi-os8!_
zqXl2b8NlP`vySuiW_=z$yXZ_yKhu)2Z*_J5MyPSi`$xcPX=f%ppUurd&z>VNnY+!7
zD625O`MswX^8t6rt>dq<v?xl1XOnpc;NhSc>Go8vKX*DQ5APc6t#W>Ruv*8#zgJNr
z|2aKTk*n9Ti9dXR`W|wAe6T7*4GmbW5rNXx^a{iMpN((L^}S=<Z!0~Uk3JslKf9Q_
zv(riW_~v_`el%M7D)Q{&l3XQQ>vW)LVBacYjIWLN2i174q`z;?bXZu77EUK+H7Qd#
z3@NuA?pp+yTsk5RN|Nn~L}E-iaADNuM6cyrYy6;R{lkIHecfP<=E-<^ICr=0jnT=b
zmz76p%X-pEWOO*N=c9f>h>_FDB|?T0O^9j203zvfKA?m=#B1}jnRvUD=XHowb%O}h
zF;cp~zRl?uhPm_j7#UC9;l<pUi@D=ySWK1H{f|e3^GWGv&u$q<8PuV{8pXa%ihj^9
zR#}$(dI*s^Mw$RfLlprUrmh;q$n0&3du^*IA%8sT`vwT>pe&~B?4W0<V`O~ku$h2>
zQ3@X-qn@P-fjSBwo?g3(evz*-;G?5Mo}FC~VuO;5L6Ot5h8QFF-;l-jZ9cl+x6gzu
zFRU;x>)FTS*=^6fmJq1~*f;vtq|?hts2dLUaxQ&MjNq$)QNq)UIU<5qaQ@NJDp$#N
zhdQ=+O-&$qdPwfhRS_2=!y-jeqn=%@Umx`BN~`SrvaIsLDnf{?Cw=F{0i=z(xN(}V
ze2uFcB!kdE<pZByIxby}(iuK9oK8xvT#eE2?D0c?{^WS-Lp-Y^j3*_d{Q{fol*C2Q
z3W{6-4bt9>N(;HUAStI#K-KYEC%zWnM9Mni>PQBtEW;?xrK{){mO){#xhD8#lj_f1
z#o+O2C)OT=@1Gry&Qoj_u}X+B5{X>83g>I85XqI^!~-IN*6EV=@2YMnaz$a(+coZd
zJ%eP13ZpnEa*jv)#0Ji$C9Y}+u|`PPL}4{Xbc!A$SS6!}PcJ%GuEK}F!@(ZDj`$Fn
zI)CV^hPkhCA?4S@J%iR@P15mt!a8dM`49*(V$^jEedoj{m+mCSNG3@`ld|ID=TpvR
zS4bvUl}wk`f=2K@(rX<>VHN$toCEyb>7)~5tVCeApJQ{O3UNGhRmWAKQ@VQA#E4Ns
zVGJN-S+Ztz9T5?%QuM9Chuco*jSeWGKn-UTN0Dd5m^6`PDGk&a)D46fXLW2&?icpl
z$ABQMZ7w%s7r7c84foI6$oaM36v&@E=zG<kt=NE%HCAh~cB4OhHhD(})Ff1-$OBrZ
zEfAaQyA~0i-|%LS5BBk8Af^?&6`Ph-7=JvTn3IP?|EeQ_gswb(K6@`O{>H<p_4T<<
zU{XXfP$JAqclh+;deTS3V&y}mt`m6WLL9$3UW`-;){$4=`d0GByF7c8u#7s^I3Gch
zL%O*IAc6DF)n_wTy*AlDq})02lL!5kWC_unm2Uj$r8}uYe5(uov;6-cxsv{W^c=oX
z`bB<xG%QY(kmpK9PagDNOMbtztmm8L$*Au|lSiOXnj$yHg%Lu+XYvr^#%%uOTgLg$
z<mAE7Z|`j7|1$lY=BwW_|NJFiybS!6*`bb0+{>?KRak7W$ln>EeHRfSKj_)xpC7%B
ztUns|rYe*CY;r}eGD1ulj@H7bmmUH3t-giQ{6V+J*`tFMl0woD;q>D2mS?m|j)y(d
z7m*ZAhKN!vK-m^JW>=oxo*BR$pzj|-KD{jYbXwvAd^&YZ%F5h$JOAk6-~`~Tg$<3l
z_MGd4*oBCB#e#e*P1{`cKf1p^u9_zATf={Q1=G0xVUX5^zX~CYde(zbhe#D_v}Bua
zg~+XhxODZc?|v&y`zpB7*SXaha~IxP0u3>e2~3^e?8{NluCz`eZq<NDh7!Tokt)ze
zndu_J*|dCmbIjK?t%Uq=P(15dGm1?^&l+46&`Nmt^uk1_B2-T==AGk%-m0)E=N$Fz
z$#~{&0XQKv<SHc&Mk`Z=ioVUKh;Y!eh`^*wwYF3RX%I=FaUGj#?yAvUS^Q>MKRq6;
zLJZWg!Pk*}YnaR(bpsCv79Uc=HMw%tcy<lcoE;ymngAw;`#-y#fhUco0N=$po?bdv
zSaU4EhxdEbP2_A=;#|FnrF|X8>zc)zWV1c)KOJ`-KAUtRV2$RYop6Ye@!YXz6|sTA
zUY<W17OP>Ap985Rp}>d8CwH(D1n@DEi<rXb;}|0$Mw}1$5DE1<rwoUavg*8P!b&86
z&@WElj_u*=6pjiYZJHHhWOC{06`HwgTF_sQ9$CFo8I-<8$goD}*?cr_!_|w@4F=Xu
ztq}%2+n<#V)t0W?IuE7u19wLhnJeiJ3Ul~yP#o7G9qGSov6t5lq86!?&ZwJI+^Oqy
zjD3vE%bLPyLTGSxY!6Jvm8&SM!pF#?gTeWFtQeX3y2jT5tu?-mOkJup(dLYG#I>3n
z^=v*J7Wrz_FIIcTOhaG;D`YqFh}R}vhcub}J%!dOQ%)-o$W4axH4WFfNT?gKOn5q;
z5@W-j(OiD=XtPb$yoowSBop?n!Ke(ak}-TZDEzRnt3hGTjmr9v5o1JJr*v6*VgtE)
zOD)vZ;S9k0lu9+N#zSn#ZhTHjdQY;9rinD9Bo!L!0R6)D0j_*H+*$;iXQ@~vf(v!B
z$HWcQ1i1A&0<Ml|of7CbPP%mUQ~+bHF^S}gGn{WQI-{y1lQOX-gyf>NWK7G7D<8-N
zE>0dz0kkA?fDjQ9IVMR)9a2Vr6Los^iZQu%=if5vwPSL1q;A?6Ac7AKJ*#oPL1nOK
z6k0US*N8xj4N42M(m|}boR^#&9Zap!<VsWex<#qdwO(zT>uXQ4QS;42I3WXaW0_yG
z9?pkpCT)ftujw5|Wt2XWn+)r8o4Kbc=u8Nqq4G7k(oC<aN;1ifNME(=ndZjww&xI|
z65Hd_-JD~>TWDlsVIq;uA9rawM5-nxYhl`AUj&BMqBP9Q8f#SIy1b$wB^i;(<L48j
z1#$)V_bo&)0={Y}tAxsyK2`SDQJv1%Y{#a#o?}Kb4mUM@XY7#)6gs)*!YD@j7Oe&6
z8%pn)d%xkyl`c>ilgiC<jhlROad`;P5ZNzsT!@rD7%fuOq2c1v<9tnssnDyGP&et@
zT1$HqsT5t+4f<`?BmGb^W&OfXC{1V@&M!+QrK5?EONLUiiNuUbi0GQ&)3^Eg%vIyE
z3RHE&8UnLM4JKt}BJpXS2|h%;j~K0)yU?1tR5n*iCCfr0vjNyPM7=x8i%?k2#ie6j
zc|M&xd}uH#OTl_fOW8DFjM{*PLb?&HG6V48>7=8wENP(uEm(lL3y<fnGQLi>J2t6y
zuXS?8Rftp}kSoFDY6JfJ7~LBuZF5EGYD^|vI!}y=u9q|$Tdk%gj4`&L`L#WDzTSAn
z()qD5k_ZUaY{JtB)$>`|nLA&tfqtvhX4~Z|jn$;6f{VF(8e2^8&PmT*pl6er5)q0#
zx!}Smbe3pv=>Q6+ld@y-WNno|-9&td)Ad--Cgq`!Ox8`uasB?>#HOigz?zJGt0{7Y
z)f%f58E`teI=or8d_#$YS?MD^Yc?5$)oJPLmLVa)vx~WbWWIEkB0{SbA>Iyv9-mDI
zv4MSS?j*22em*nL#<P~DClp2}>Rwqr{dhd<yowjznQr;IVPG{rTyq@i2H={5d2#6;
zuc-(=#J2*YWff+Uy&XG^k?K`k`b~1Drb{2Dsluu^UNM6<Zh%?o$7L0+Q=lfn!FBx_
zV|XKvPiLK*@x$*TZ?GQG*D=}0wd7{a)QL>WY7?jrdnp;%Gdgh?oqr?r`|<hZoh*~z
z%cM(RJCh6R{Li-Vln6X~1*f)JkJhPwVKu&vXK(s3SB2jTWc(%w!TUCkw?-&^z+}SH
zi}EIJLC>mD(=a}Kdh!0$n%_b0oV3yUkQfQ=?$DWVe(4Txa)1ElE{tC-{C^kn+NAqM
ze)8y`IF1pV_p|Y(J9(7>^+zXn(RcnVf0jSXx0PJU=s~~mkA}thH+}Yxrt<Q~CN@|7
z;l6oljq0bYEW_r4t6B)Fu4h$<{icDzo<W2Glk%-&{#n^Kq{vnO<HNz&*D<$7m^#no
zvVz#4RE9Vqww#aQzUdDOMOg*32)UB{)pFdc@<&mg`;QhS<WK(l@R!3q`#*QTC)+Q7
z8+mr|?}YF*`8Mq89pYliA}-k$$g(b9zFhEPvET<S$f~tag+=xGTLQ#CD!%ReiW12S
zqXzrdJRB5eB$AS<1kei8(s4E|2X7-)42%5a!Eo<bw-C<hWKN6?xk`X!X!Cdx$g&oi
z%(wx7MfPou(V8po$3Gj--xvV@$(j+Xq(9uZ)4GY+JSl2T%$t^;x{l0B_xMeURzm;b
zpqQFmp(Q~{&U=hbiDXJJ5?Z;Irb$3veS=FGfk|0$P-F}XJNg;(H_rJ#OxYsjJ)1wY
zN}GW-gVWjN$$MrQW{pi>x(XY?XpL4vbdig>8@!5dtfgnwd6ApZuxDHDY9urbr4PiI
zP{v&J2G(5z?U6{Vuc6=@_rlb9BujR`e1j?ZPL=&=*qaUu(^oANR>w%?8?+Wq9t_VX
zb2t0h8~R0F6S-N^7OD`iEh%{F{L{M>twct{!kmi;hXafAkv*gFA#zzJzqYO_ua#Uk
zEjK(uD&AxpT<0c|7Gk9IH9cz%f3M2UmGrfU=~+Fvzi%J5Kb>DWUxmnYa^+6$`oU+D
z`QUUi&xbubS0edv&yeekx=tA6uxI;PiGMPl^<L#BzAA!P9~-o!LYdAaRrI0|8*atC
zBJ_ua9V?MM60t@Bf@xug*fbmbY2Bpd>zH==MlytJ1WnonaCJTQA)JKB?BdN91bBn8
zl}K)s40={S+%sx)a|x|Z^#C6tv1xEVbs6L;*##HksL1t*7DF9R-FPy0kJjKsgzBR0
z7_LHnJ{s<gOk3Lu0Scq@Cr3m7_;h08TNExCMoVIT@7rrucWwlg$p*dY+k9$N)?b^1
z4B`I1#rcGemsKi;$F|0NTfuDT2LL`cGv~rdjB)xZ*zzuNCoR|JYS6R#;b1QxMZidg
zs~gsiczxs$kSrAvn<n9F!@>fIFkShE++?YvB2`#t-p5-&%Y(i>AMDwYT^AGEMXF-M
z*{9{<n?RYK&CjjMMj<vE^C1XF2m72(F2@&_&h@N5rll}P(qdX8jQRzTfXfCLPfMJy
zH?492O{8*lIH^K>de`rN8~Mi2ugKMCG%U__wl2$obM=OY)ZEwzRY)}a;l4#F!B>IM
zeqib<bS5-SgiJ6ZOiK4yi!kijlR89(Jxd4?Uq@;h_Oxc|UTtkjk}DbQTk|ZvybjSG
z9S(_2!|BBg5g~*~YzZ<Vuy1qnOtWVdS3Wg#Jb6Byl|D>Ej3<1H9lPG3!#(rR<jM$H
zzh@P57iP~crpIe0#y8sRvI=9JrF1pa4Zh`~tYuAR5CNlAt5}a!3D(w1@S#R$>3I`I
zWoVLT-?!#ODM4wdV<MM59Hw1I4UNE{Fnw!`e{weI-OSFa5XTpDH|`g?uS1h(>-rCZ
z)(~Q94nb0lHMC5T!ltIi<_7P*YU1&mA{R)GRRn8|dYnO?E6x4=#Cobj#I$L=kZN&N
zh<tcDdF@oblY_jxs>Z{8J2FZmA>v6*BR6+-(^hZR(zD>}RD8B3qi0j+O^k3AlG0_}
zE7LX%W?AHPGH1A#THt($m|UT9$xn|*{@KOsa58tdZXndrsZ8>9D{~?-wd)m|c1l93
zBxDdFGl?0vXB1a1pfVX0xq2*_478BTjq3NB<Cb1Go1**qwA|e7!M?>R!G*LD+vI9f
z3tY=PrRyKu(?8uoikBfG*%n^|aS_ROge+So$CD*95|&@FSVnfYxB0+mmYojOi&U5X
z&5H#hu)`K+H#w|s7q+@xUPf5P2+Jk^_PJ+C#O&@6BmBT<x}7b4ykGqE-o4$OU(G-N
z<$7*AUDS&he<GbOU$f+cdxq_;EnY4bgs@<DJ44GBvb}`}{PhpE>CyqZbi1%vEcu%F
zljU+*nC)zv?$)h)?{;s#-eL)KmupsK+O09d2X>dZh=h8{?oO9~{#E%8uj=ug7?ZB5
z&kCz4tlq5hHIWPInhjGX5d<`KNZm+UNL;C=!G{`G)ws}bS*FH{HHFja6mFGOIxeNF
znO^$jBYcf%2?zK4y<`9BCz~fQtey7y^_nPYl-_i*Cl*A@`Dqg&eIvDBe|K{(Tbk)6
zzP|CA8=qVMm#YIIv`tYo_;_~{_B$y%HtFU|SEr+tWoQkFMG`m3g-D`5RV}Gk0Oy-T
z=&b^=S@XH#hUK<C{zkHv)0M_hk^zx<>F^;?I**ZvbB@}({Oac)t%^MFhY-)KNz4o_
z8JAZM?`!h*`9n7^NakasteBWgxl&~9lC5zNB`M|>mFO#K&Eet3CD(m+zK-NdP?;vw
zk;8$##d?KzG$T9PqK<z2*GI-=#ASyszG|2|&&!vQMO-4?Ef%pM#wA}Zm+VM}l5M`P
zcQCsdFYB*xF9KT~*vWR#+Zo+%I@Y^8!g84ic8lebFJ4BrSR&h7EFvu8lFQQ1LR|iO
zcUy`Viv^)tptG;pxA%@B%S!0{B$Es!p!GJ}SuzD~^I)DxWXUovSu7&=j1Xg|efUq8
zootKJzeI`9?RIZm$xL+NmH%(A_Pr&ropmugTkI+!{x-5?S^cW4e(~PQ4vYAu)!+O3
zmmzL<x3<{YTJlx>Tb69m?QXH4p;^L~WbAHl@#7D2_U~!jiyFS}z}6Q2MPyq#>}sJ)
z7roPkWtZg=7I9hK+uqrJxmZw#$W|9(T&4v9eqeU)olQO)mQ_8w|6j~czgjGaOMoT!
zc6WZVv)$$MFJI7=EtV}4XIF&(_1Whv=@6H#?QO5^?JiqO&^qIbu)u70S<<ERb)>Te
zTkW-6zOIWbgRLcOW!Im}wqP5fyVXH&3t<t-vP@sh-K`k?omuXCHlx?t?7B{H<Bcg`
zB*SW9xMzV3-_kZ*T{CySH8ttDt#OBS2$^Lm*~nE&xl>GhO%F{}Jh5|EjgOvPm`ns8
z0;<JFB!h$A9wA(}<oXz?BTwtt;C#*8rK@x`<C#m%pCPu{w_w@`q;9UGES+(~=BK~g
z+XZf$sL+=5Z?qu1X0zY9c%Zv7h)as@))u>Zi`|_r_tZ9acbC8YVd_EdF1OG-!ad#P
zSD$(QrTmgFLj;!iMZ<4nhwW|x-?z4siJ-fL<#O@Y_jb2+wnga|$v*A~FY6SYd|(t>
zwscvAU&JMg@vlGs$DUPxlWk@9%yyTTbwp)b{OE&wIKN<5!%jEj?BB}6|5Js3SS;c{
z{pbVpKkn^j+sogA&?UsLu|{)G2_Y`YvM$RmxN1RMF4@hxhzQ#P(uEM0tT(y<T@kXZ
zySeBlU$eEfWOrMr>LvgCbN5ei$>P10ZFYC={q5l1PdeQtFJCmgSVVsFa=~X`yyP=q
z@vE}p#Uk>VtGFn?z%LdomrHiKTXehd1HFTEyDXMVmMqab+mK8M(v|J33p?2sFBg%m
ztuBi?vMs{y?l#*3i%9Xoy`8@=zf44?UzOEqTrPKhWOoNI7b#49v55TWgIyMN2cx%{
zfBwa+TEub*i_fd@wEQys<03A9`NMnqeplEozX<%$?()?FcDErcIut(;mUO9?OBTxo
z9l*U<kS)8&j<DVBvc26!cZHp9mu`1ScoFG#mYD4ns_LCCi?5fIU(~agi?}IFzO%Bo
zGmP2Z{prh>4d2_z_`c3?FBf#_@-lwKS8+)d0wKb^?PR;ZuXk9oBnFb=ce?CkUG&yA
zaT(d#f?d5$r;~QWqIF<jw2IalX@M4zu#EVs`Q?{kv2i+|SK*gs_0?xT{^9q38Wu~m
z2wyB}x?4-M+QC)f%d!f;ym=pSx%{%M!c+HU_$QUgUjfDL&JJ4waj``2Zn0d#c2~&g
zvMt+u{q>S&37t+d{$Y_Ig%^uR=j$ck+Z6`IJ(gcD>2AS}bouAWzd!!<Z(jcM&EJ0K
zvY1t>fAVlJU6-C*T{9_t`#6FG0u}k1+a8JGx@!(@V<>CeSCh=&^vXXjjOO96I9d1T
zWbGr4gcQf>OgNw3T@Vl<e=_R(qHRd>O@qlYV$;kXKc9UgJ}!`-91Xn|p^g#XH0<e&
zCPHW$>d1x!oRL7bhQw7bOd=xNmLB`*r5it=-Tm05cgC|_2s4BYGPiFHF2v2_HeyVr
zBxyOfqNU~G%BGBzo~xA}_olT#9jeo|(J4az2ofQ<3Y%Crk&%VEiPf9%ix^WM{>g*>
zRLJ`4N24j7*>}0O$huV?Mm>8n*w2qs%&&>SzDZAKuqGjs2fc(cmc9l7=fdpCcsBYb
z4F0_ezDNDy{9s^5B7$>)dFAmwZgy~LkGQVY(UR`7_L%`8#`V9|`P7YGRo>4ZrKYTT
z=}Fa`l%-lDT+IE`xvO4F6ke5so;?}v=f^ZqSi{4oWAjZ)c#|k09~SnpP6?9Tx5`Y*
zYC8Az`M052zE`D2G8{1_3&sd!1|en6>jr_FiY7}(EoE0AQJ6bFzDa)Fj4kA$ecX|>
z3scvL<r^dTI=lw#+$9%t_xRHJ^N$Y)(-0zs%?Gpc+dWGmM5^)py8rR{@5o|(uWr)P
z*WR}eIf<=3y8#)bu04{{bCc3#k#%oP<a9DOcPTno(tkK8{2GH;<1bnZrrqJy9Z$-5
zlT;zjK0KXt>KH36?`BHA3wf`dUDwfBl~_Pl33--r)m(RwSfh~E&Q>9j<*N{xT)M-%
z9xDP#(f9Z5)VA#fbxcLrOJ8pat5^QbRPVRRho=+s&7b=2<UP%ZY)pu29foP2>#|m|
zZ>u#C!PVhbr|+whE9oB%i)lvk>HyPAKh_ycuKZby(cjf?`ll-I<sfaY`kx#Pr>@=E
zrH?3`5Wx^5zKNJNjek>^_MchaIjQMcb#nYS`=>7#5hId-_pg@;{0DY-1(wU%=U>#n
z82|b=|1~a`U;Y8-{U<5kxU)xndp@xF$mk4LH?vDuP3NvY_aV5qQ4Rhqugm`fNI@&~
z^&rlb0002SdQ@0+L}hbha%pgMX>V=-00@~)%Rx%SKoAAceNOS03Nv9q@C4#c9pVtz
zJ>5S^K~mLpRYr1qx4!)wsD+IM_XAfp7Y}MCY{Domrg)0&8ACd7YbmpJBb$pUUi!-k
zyNk|<g}BK^$0vU=*p?KNX&`CA+sFHlS$XZdZ_!L#zsB>B4iuw9El{K}uW`WlTCD{{
zgKbTj1-3`s<J83>j!9NxNsc?I$fggrU_ls?{$H}CnRrM->Z*C1YqLyu(HS1B{U2@!
VS0jWSKIQ-b002ovPDHLkV1m0U00;m8

diff --git a/extern/libpng/include/pngtrans.c b/extern/libpng/include/pngtrans.c
deleted file mode 100644
index fef12f1851..0000000000
--- a/extern/libpng/include/pngtrans.c
+++ /dev/null
@@ -1,781 +0,0 @@
-
-/* pngtrans.c - transforms the data in a row (used by both readers and writers)
- *
- * Last changed in libpng 1.5.10 [March 8, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#include "pngpriv.h"
-
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-
-#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
-/* Turn on BGR-to-RGB mapping */
-void PNGAPI
-png_set_bgr(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_bgr");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_BGR;
-}
-#endif
-
-#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
-/* Turn on 16 bit byte swapping */
-void PNGAPI
-png_set_swap(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_swap");
-
-   if (png_ptr == NULL)
-      return;
-
-   if (png_ptr->bit_depth == 16)
-      png_ptr->transformations |= PNG_SWAP_BYTES;
-}
-#endif
-
-#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
-/* Turn on pixel packing */
-void PNGAPI
-png_set_packing(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_packing");
-
-   if (png_ptr == NULL)
-      return;
-
-   if (png_ptr->bit_depth < 8)
-   {
-      png_ptr->transformations |= PNG_PACK;
-      png_ptr->usr_bit_depth = 8;
-   }
-}
-#endif
-
-#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
-/* Turn on packed pixel swapping */
-void PNGAPI
-png_set_packswap(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_packswap");
-
-   if (png_ptr == NULL)
-      return;
-
-   if (png_ptr->bit_depth < 8)
-      png_ptr->transformations |= PNG_PACKSWAP;
-}
-#endif
-
-#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
-void PNGAPI
-png_set_shift(png_structp png_ptr, png_const_color_8p true_bits)
-{
-   png_debug(1, "in png_set_shift");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_SHIFT;
-   png_ptr->shift = *true_bits;
-}
-#endif
-
-#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
-    defined(PNG_WRITE_INTERLACING_SUPPORTED)
-int PNGAPI
-png_set_interlace_handling(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_interlace handling");
-
-   if (png_ptr && png_ptr->interlaced)
-   {
-      png_ptr->transformations |= PNG_INTERLACE;
-      return (7);
-   }
-
-   return (1);
-}
-#endif
-
-#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
-/* Add a filler byte on read, or remove a filler or alpha byte on write.
- * The filler type has changed in v0.95 to allow future 2-byte fillers
- * for 48-bit input data, as well as to avoid problems with some compilers
- * that don't like bytes as parameters.
- */
-void PNGAPI
-png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
-{
-   png_debug(1, "in png_set_filler");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_FILLER;
-   png_ptr->filler = (png_uint_16)filler;
-
-   if (filler_loc == PNG_FILLER_AFTER)
-      png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
-
-   else
-      png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
-
-   /* This should probably go in the "do_read_filler" routine.
-    * I attempted to do that in libpng-1.0.1a but that caused problems
-    * so I restored it in libpng-1.0.2a
-   */
-
-   if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
-   {
-      png_ptr->usr_channels = 4;
-   }
-
-   /* Also I added this in libpng-1.0.2a (what happens when we expand
-    * a less-than-8-bit grayscale to GA?) */
-
-   if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY && png_ptr->bit_depth >= 8)
-   {
-      png_ptr->usr_channels = 2;
-   }
-}
-
-/* Added to libpng-1.2.7 */
-void PNGAPI
-png_set_add_alpha(png_structp png_ptr, png_uint_32 filler, int filler_loc)
-{
-   png_debug(1, "in png_set_add_alpha");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_set_filler(png_ptr, filler, filler_loc);
-   png_ptr->transformations |= PNG_ADD_ALPHA;
-}
-
-#endif
-
-#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
-    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
-void PNGAPI
-png_set_swap_alpha(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_swap_alpha");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_SWAP_ALPHA;
-}
-#endif
-
-#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
-    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
-void PNGAPI
-png_set_invert_alpha(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_invert_alpha");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_INVERT_ALPHA;
-}
-#endif
-
-#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
-void PNGAPI
-png_set_invert_mono(png_structp png_ptr)
-{
-   png_debug(1, "in png_set_invert_mono");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_INVERT_MONO;
-}
-
-/* Invert monochrome grayscale data */
-void /* PRIVATE */
-png_do_invert(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_invert");
-
-  /* This test removed from libpng version 1.0.13 and 1.2.0:
-   *   if (row_info->bit_depth == 1 &&
-   */
-   if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
-   {
-      png_bytep rp = row;
-      png_size_t i;
-      png_size_t istop = row_info->rowbytes;
-
-      for (i = 0; i < istop; i++)
-      {
-         *rp = (png_byte)(~(*rp));
-         rp++;
-      }
-   }
-
-   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
-      row_info->bit_depth == 8)
-   {
-      png_bytep rp = row;
-      png_size_t i;
-      png_size_t istop = row_info->rowbytes;
-
-      for (i = 0; i < istop; i += 2)
-      {
-         *rp = (png_byte)(~(*rp));
-         rp += 2;
-      }
-   }
-
-#ifdef PNG_16BIT_SUPPORTED
-   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
-      row_info->bit_depth == 16)
-   {
-      png_bytep rp = row;
-      png_size_t i;
-      png_size_t istop = row_info->rowbytes;
-
-      for (i = 0; i < istop; i += 4)
-      {
-         *rp = (png_byte)(~(*rp));
-         *(rp + 1) = (png_byte)(~(*(rp + 1)));
-         rp += 4;
-      }
-   }
-#endif
-}
-#endif
-
-#ifdef PNG_16BIT_SUPPORTED
-#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
-/* Swaps byte order on 16 bit depth images */
-void /* PRIVATE */
-png_do_swap(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_swap");
-
-   if (row_info->bit_depth == 16)
-   {
-      png_bytep rp = row;
-      png_uint_32 i;
-      png_uint_32 istop= row_info->width * row_info->channels;
-
-      for (i = 0; i < istop; i++, rp += 2)
-      {
-         png_byte t = *rp;
-         *rp = *(rp + 1);
-         *(rp + 1) = t;
-      }
-   }
-}
-#endif
-#endif
-
-#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
-static PNG_CONST png_byte onebppswaptable[256] = {
-   0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
-   0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
-   0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
-   0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
-   0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
-   0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
-   0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
-   0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
-   0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
-   0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
-   0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
-   0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
-   0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
-   0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
-   0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
-   0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
-   0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
-   0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
-   0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
-   0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
-   0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
-   0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
-   0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
-   0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
-   0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
-   0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
-   0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
-   0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
-   0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
-   0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
-   0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
-   0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
-};
-
-static PNG_CONST png_byte twobppswaptable[256] = {
-   0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
-   0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
-   0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
-   0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
-   0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
-   0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
-   0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
-   0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
-   0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
-   0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
-   0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
-   0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
-   0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
-   0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
-   0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
-   0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
-   0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
-   0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
-   0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
-   0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
-   0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
-   0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
-   0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
-   0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
-   0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
-   0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
-   0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
-   0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
-   0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
-   0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
-   0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
-   0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
-};
-
-static PNG_CONST png_byte fourbppswaptable[256] = {
-   0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
-   0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
-   0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
-   0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
-   0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
-   0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
-   0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
-   0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
-   0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
-   0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
-   0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
-   0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
-   0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
-   0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
-   0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
-   0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
-   0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
-   0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
-   0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
-   0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
-   0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
-   0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
-   0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
-   0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
-   0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
-   0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
-   0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
-   0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
-   0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
-   0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
-   0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
-   0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
-};
-
-/* Swaps pixel packing order within bytes */
-void /* PRIVATE */
-png_do_packswap(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_packswap");
-
-   if (row_info->bit_depth < 8)
-   {
-      png_bytep rp;
-      png_const_bytep end, table;
-
-      end = row + row_info->rowbytes;
-
-      if (row_info->bit_depth == 1)
-         table = onebppswaptable;
-
-      else if (row_info->bit_depth == 2)
-         table = twobppswaptable;
-
-      else if (row_info->bit_depth == 4)
-         table = fourbppswaptable;
-
-      else
-         return;
-
-      for (rp = row; rp < end; rp++)
-         *rp = table[*rp];
-   }
-}
-#endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */
-
-#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
-    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
-/* Remove a channel - this used to be 'png_do_strip_filler' but it used a
- * somewhat weird combination of flags to determine what to do.  All the calls
- * to png_do_strip_filler are changed in 1.5.2 to call this instead with the
- * correct arguments.
- *
- * The routine isn't general - the channel must be the channel at the start or
- * end (not in the middle) of each pixel.
- */
-void /* PRIVATE */
-png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
-{
-   png_bytep sp = row; /* source pointer */
-   png_bytep dp = row; /* destination pointer */
-   png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */
-
-   /* At the start sp will point to the first byte to copy and dp to where
-    * it is copied to.  ep always points just beyond the end of the row, so
-    * the loop simply copies (channels-1) channels until sp reaches ep.
-    *
-    * at_start:        0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
-    *            nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
-    */
-
-   /* GA, GX, XG cases */
-   if (row_info->channels == 2)
-   {
-      if (row_info->bit_depth == 8)
-      {
-         if (at_start) /* Skip initial filler */
-            ++sp;
-         else          /* Skip initial channel and, for sp, the filler */
-            sp += 2, ++dp;
-
-         /* For a 1 pixel wide image there is nothing to do */
-         while (sp < ep)
-            *dp++ = *sp, sp += 2;
-
-         row_info->pixel_depth = 8;
-      }
-
-      else if (row_info->bit_depth == 16)
-      {
-         if (at_start) /* Skip initial filler */
-            sp += 2;
-         else          /* Skip initial channel and, for sp, the filler */
-            sp += 4, dp += 2;
-
-         while (sp < ep)
-            *dp++ = *sp++, *dp++ = *sp, sp += 3;
-
-         row_info->pixel_depth = 16;
-      }
-
-      else
-         return; /* bad bit depth */
-
-      row_info->channels = 1;
-
-      /* Finally fix the color type if it records an alpha channel */
-      if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-         row_info->color_type = PNG_COLOR_TYPE_GRAY;
-   }
-
-   /* RGBA, RGBX, XRGB cases */
-   else if (row_info->channels == 4)
-   {
-      if (row_info->bit_depth == 8)
-      {
-         if (at_start) /* Skip initial filler */
-            ++sp;
-         else          /* Skip initial channels and, for sp, the filler */
-            sp += 4, dp += 3;
-
-         /* Note that the loop adds 3 to dp and 4 to sp each time. */
-         while (sp < ep)
-            *dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2;
-
-         row_info->pixel_depth = 24;
-      }
-
-      else if (row_info->bit_depth == 16)
-      {
-         if (at_start) /* Skip initial filler */
-            sp += 2;
-         else          /* Skip initial channels and, for sp, the filler */
-            sp += 8, dp += 6;
-
-         while (sp < ep)
-         {
-            /* Copy 6 bytes, skip 2 */
-            *dp++ = *sp++, *dp++ = *sp++;
-            *dp++ = *sp++, *dp++ = *sp++;
-            *dp++ = *sp++, *dp++ = *sp, sp += 3;
-         }
-
-         row_info->pixel_depth = 48;
-      }
-
-      else
-         return; /* bad bit depth */
-
-      row_info->channels = 3;
-
-      /* Finally fix the color type if it records an alpha channel */
-      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-         row_info->color_type = PNG_COLOR_TYPE_RGB;
-   }
-
-   else
-      return; /* The filler channel has gone already */
-
-   /* Fix the rowbytes value. */
-   row_info->rowbytes = dp-row;
-}
-#endif
-
-#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
-/* Swaps red and blue bytes within a pixel */
-void /* PRIVATE */
-png_do_bgr(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_bgr");
-
-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
-   {
-      png_uint_32 row_width = row_info->width;
-      if (row_info->bit_depth == 8)
-      {
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-         {
-            png_bytep rp;
-            png_uint_32 i;
-
-            for (i = 0, rp = row; i < row_width; i++, rp += 3)
-            {
-               png_byte save = *rp;
-               *rp = *(rp + 2);
-               *(rp + 2) = save;
-            }
-         }
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-         {
-            png_bytep rp;
-            png_uint_32 i;
-
-            for (i = 0, rp = row; i < row_width; i++, rp += 4)
-            {
-               png_byte save = *rp;
-               *rp = *(rp + 2);
-               *(rp + 2) = save;
-            }
-         }
-      }
-
-#ifdef PNG_16BIT_SUPPORTED
-      else if (row_info->bit_depth == 16)
-      {
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-         {
-            png_bytep rp;
-            png_uint_32 i;
-
-            for (i = 0, rp = row; i < row_width; i++, rp += 6)
-            {
-               png_byte save = *rp;
-               *rp = *(rp + 4);
-               *(rp + 4) = save;
-               save = *(rp + 1);
-               *(rp + 1) = *(rp + 5);
-               *(rp + 5) = save;
-            }
-         }
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-         {
-            png_bytep rp;
-            png_uint_32 i;
-
-            for (i = 0, rp = row; i < row_width; i++, rp += 8)
-            {
-               png_byte save = *rp;
-               *rp = *(rp + 4);
-               *(rp + 4) = save;
-               save = *(rp + 1);
-               *(rp + 1) = *(rp + 5);
-               *(rp + 5) = save;
-            }
-         }
-      }
-#endif
-   }
-}
-#endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
-
-#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
-    defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
-/* Added at libpng-1.5.10 */
-void /* PRIVATE */
-png_do_check_palette_indexes(png_structp png_ptr, png_row_infop row_info)
-{
-   if (png_ptr->num_palette < (1 << row_info->bit_depth) &&
-      png_ptr->num_palette_max >= 0)
-   {
-      /* Calculations moved outside switch in an attempt to stop different
-       * compiler warnings.  'padding' is in *bits* within the last byte, it is
-       * an 'int' because pixel_depth becomes an 'int' in the expression below,
-       * and this calculation is used because it avoids warnings that other
-       * forms produced on either GCC or MSVC.
-       */
-      int padding = (-row_info->pixel_depth * row_info->width) & 7;
-      png_bytep rp = png_ptr->row_buf + row_info->rowbytes;
-
-      switch (row_info->bit_depth)
-      {
-         case 1:
-         {
-            /* in this case, all bytes must be 0 so we don't need
-             * to unpack the pixels except for the rightmost one.
-             */
-            for (; rp > png_ptr->row_buf; rp--)
-            {
-              if (*rp >> padding != 0)
-                 png_ptr->num_palette_max = 1;
-              padding = 0;
-            }
-
-            break;
-         }
-
-         case 2:
-         {
-            for (; rp > png_ptr->row_buf; rp--)
-            {
-              int i = ((*rp >> padding) & 0x03);
-
-              if (i > png_ptr->num_palette_max)
-                 png_ptr->num_palette_max = i;
-
-              i = (((*rp >> padding) >> 2) & 0x03);
-
-              if (i > png_ptr->num_palette_max)
-                 png_ptr->num_palette_max = i;
-
-              i = (((*rp >> padding) >> 4) & 0x03);
-
-              if (i > png_ptr->num_palette_max)
-                 png_ptr->num_palette_max = i;
-
-              i = (((*rp >> padding) >> 6) & 0x03);
-
-              if (i > png_ptr->num_palette_max)
-                 png_ptr->num_palette_max = i;
-
-              padding = 0;
-            }
-
-            break;
-         }
-
-         case 4:
-         {
-            for (; rp > png_ptr->row_buf; rp--)
-            {
-              int i = ((*rp >> padding) & 0x0f);
-
-              if (i > png_ptr->num_palette_max)
-                 png_ptr->num_palette_max = i;
-
-              i = (((*rp >> padding) >> 4) & 0x0f);
-
-              if (i > png_ptr->num_palette_max)
-                 png_ptr->num_palette_max = i;
-
-              padding = 0;
-            }
-
-            break;
-         }
-
-         case 8:
-         {
-            for (; rp > png_ptr->row_buf; rp--)
-            {
-               if (*rp >= png_ptr->num_palette_max)
-                  png_ptr->num_palette_max = (int) *rp;
-            }
-
-            break;
-         }
-
-         default:
-            break;
-      }
-   }
-}
-#endif /* PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED */
-
-#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
-    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
-#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-void PNGAPI
-png_set_user_transform_info(png_structp png_ptr, png_voidp
-   user_transform_ptr, int user_transform_depth, int user_transform_channels)
-{
-   png_debug(1, "in png_set_user_transform_info");
-
-   if (png_ptr == NULL)
-      return;
-   png_ptr->user_transform_ptr = user_transform_ptr;
-   png_ptr->user_transform_depth = (png_byte)user_transform_depth;
-   png_ptr->user_transform_channels = (png_byte)user_transform_channels;
-}
-#endif
-
-/* This function returns a pointer to the user_transform_ptr associated with
- * the user transform functions.  The application should free any memory
- * associated with this pointer before png_write_destroy and png_read_destroy
- * are called.
- */
-#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-png_voidp PNGAPI
-png_get_user_transform_ptr(png_const_structp png_ptr)
-{
-   if (png_ptr == NULL)
-      return (NULL);
-
-   return ((png_voidp)png_ptr->user_transform_ptr);
-}
-#endif
-
-#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
-png_uint_32 PNGAPI
-png_get_current_row_number(png_const_structp png_ptr)
-{
-   /* See the comments in png.h - this is the sub-image row when reading and
-    * interlaced image.
-    */
-   if (png_ptr != NULL)
-      return png_ptr->row_number;
-
-   return PNG_UINT_32_MAX; /* help the app not to fail silently */
-}
-
-png_byte PNGAPI
-png_get_current_pass_number(png_const_structp png_ptr)
-{
-   if (png_ptr != NULL)
-      return png_ptr->pass;
-   return 8; /* invalid */
-}
-#endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */
-#endif /* PNG_READ_USER_TRANSFORM_SUPPORTED ||
-          PNG_WRITE_USER_TRANSFORM_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/extern/libpng/include/pngusr.dfa b/extern/libpng/include/pngusr.dfa
deleted file mode 100644
index 9d39564b51..0000000000
--- a/extern/libpng/include/pngusr.dfa
+++ /dev/null
@@ -1,14 +0,0 @@
-# pngusr.dfa
-#
-# Build time configuration of libpng
-#
-# Enter build configuration options in this file
-#
-# Security settings: by default these limits are unset, you can change them
-# here by entering the appropriate values as #defines preceded by '@' (to cause,
-# them to be passed through to the build of pnglibconf.h), for example:
-#
-# @# define PNG_USER_WIDTH_MAX 1000000
-# @# define PNG_USER_HEIGHT_MAX 1000000
-# @# define PNG_USER_CHUNK_CACHE_MAX 128
-# @# define PNG_USER_CHUNK_MALLOC_MAX 8000000
diff --git a/extern/libpng/include/pngvalid.c b/extern/libpng/include/pngvalid.c
deleted file mode 100644
index 51def95ba0..0000000000
--- a/extern/libpng/include/pngvalid.c
+++ /dev/null
@@ -1,6658 +0,0 @@
-
-/* pngvalid.c - validate libpng by constructing then reading png files.
- *
- * Last changed in libpng 1.5.1 [February 3, 2011]
- * Copyright (c) 2011 Glenn Randers-Pehrson
- * Written by John Cunningham Bowler
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * NOTES:
- *   This is a C program that is intended to be linked against libpng.  It
- *   generates bitmaps internally, stores them as PNG files (using the
- *   sequential write code) then reads them back (using the sequential
- *   read code) and validates that the result has the correct data.
- *
- *   The program can be modified and extended to test the correctness of
- *   transformations performed by libpng.
- */
-
-#include "png.h"
-#if PNG_LIBPNG_VER < 10500
-/* This delibarately lacks the PNG_CONST. */
-typedef png_byte *png_const_bytep;
-
-/* This is copied from 1.5.1 png.h: */
-#define PNG_INTERLACE_ADAM7_PASSES 7
-#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
-#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
-#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
-#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
-#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
-   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
-#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
-   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
-#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
-   (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
-#define PNG_COL_FROM_PASS_COL(xIn, pass) \
-   (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
-#define PNG_PASS_MASK(pass,off) ( \
-   ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
-   ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
-#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
-   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
-#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
-   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
-
-/* These are needed too for the defualt build: */
-#define PNG_WRITE_16BIT_SUPPORTED
-#define PNG_READ_16BIT_SUPPORTED
-#endif
-
-#include "zlib.h"   /* For crc32 */
-
-#include <float.h>  /* For floating point constants */
-#include <stdlib.h> /* For malloc */
-#include <string.h> /* For memcpy, memset */
-#include <math.h>   /* For floor */
-
-/* Unused formal parameter errors are removed using the following macro which is
- * expected to have no bad effects on performance.
- */
-#ifndef UNUSED
-#  if defined(__GNUC__) || defined(_MSC_VER)
-#     define UNUSED(param) (void)param;
-#  else
-#     define UNUSED(param)
-#  endif
-#endif
-
-/***************************** EXCEPTION HANDLING *****************************/
-#include "contrib/visupng/cexcept.h"
-struct png_store;
-define_exception_type(struct png_store*);
-
-/* The following are macros to reduce typing everywhere where the well known
- * name 'the_exception_context' must be defined.
- */
-#define anon_context(ps) struct exception_context *the_exception_context = \
-   &(ps)->exception_context
-#define context(ps,fault) anon_context(ps); png_store *fault
-
-/******************************* UTILITIES ************************************/
-/* Error handling is particularly problematic in production code - error
- * handlers often themselves have bugs which lead to programs that detect
- * minor errors crashing.  The following functions deal with one very
- * common class of errors in error handlers - attempting to format error or
- * warning messages into buffers that are too small.
- */
-static size_t safecat(char *buffer, size_t bufsize, size_t pos,
-   PNG_CONST char *cat)
-{
-   while (pos < bufsize && cat != NULL && *cat != 0)
-      buffer[pos++] = *cat++;
-
-   if (pos >= bufsize)
-      pos = bufsize-1;
-
-   buffer[pos] = 0;
-   return pos;
-}
-
-static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
-{
-   char number[64];
-   sprintf(number, "%d", n);
-   return safecat(buffer, bufsize, pos, number);
-}
-
-static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
-    int precision)
-{
-   char number[64];
-   sprintf(number, "%.*f", precision, d);
-   return safecat(buffer, bufsize, pos, number);
-}
-
-static PNG_CONST char invalid[] = "invalid";
-static PNG_CONST char sep[] = ": ";
-
-/* NOTE: this is indexed by ln2(bit_depth)! */
-static PNG_CONST char *bit_depths[8] =
-{
-   "1", "2", "4", "8", "16", invalid, invalid, invalid
-};
-
-static PNG_CONST char *colour_types[8] =
-{
-   "greyscale", invalid, "truecolour", "indexed-colour",
-   "greyscale with alpha", invalid, "truecolour with alpha", invalid
-};
-
-/* To get log-bit-depth from bit depth, returns 0 to 7 (7 on error). */
-static unsigned int
-log2depth(png_byte bit_depth)
-{
-   switch (bit_depth)
-   {
-      case 1:
-         return 0;
-
-      case 2:
-         return 1;
-
-      case 4:
-         return 2;
-
-      case 8:
-         return 3;
-
-      case 16:
-         return 4;
-
-      default:
-         return 7;
-   }
-}
-
-/* A numeric ID based on PNG file characteristics.  The 'do_interlace' field
- * simply records whether pngvalid did the interlace itself or whether it
- * was done by libpng.  Width and height must be less than 256.
- */
-#define FILEID(col, depth, interlace, width, height, do_interlace) \
-   ((png_uint_32)((col) + ((depth)<<3) + ((interlace)<<8) + \
-    (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
-
-#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
-#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
-#define INTERLACE_FROM_ID(id) ((int)(((id) >> 8) & 0x3))
-#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
-#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
-#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
-
-/* Utility to construct a standard name for a standard image. */
-static size_t
-standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
-    int log_bit_depth, int interlace_type, png_uint_32 w, png_uint_32 h,
-    int do_interlace)
-{
-   pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
-   pos = safecat(buffer, bufsize, pos, " ");
-   pos = safecat(buffer, bufsize, pos, bit_depths[log_bit_depth]);
-   pos = safecat(buffer, bufsize, pos, " bit ");
-
-   if (interlace_type != PNG_INTERLACE_NONE)
-      pos = safecat(buffer, bufsize, pos, "interlaced");
-   if (do_interlace)
-      pos = safecat(buffer, bufsize, pos, "(pngvalid)");
-   else
-      pos = safecat(buffer, bufsize, pos, "(libpng)");
-   if (w > 0 || h > 0)
-   {
-      pos = safecat(buffer, bufsize, pos, " ");
-      pos = safecatn(buffer, bufsize, pos, w);
-      pos = safecat(buffer, bufsize, pos, "x");
-      pos = safecatn(buffer, bufsize, pos, h);
-   }
-
-   return pos;
-}
-
-static size_t
-standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
-{
-   return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
-      log2depth(DEPTH_FROM_ID(id)), INTERLACE_FROM_ID(id),
-      WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
-}
-
-/* Convenience API and defines to list valid formats.  Note that 16 bit read and
- * write support is required to do 16 bit read tests (we must be able to make a
- * 16 bit image to test!)
- */
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-#  define WRITE_BDHI 4
-#  ifdef PNG_READ_16BIT_SUPPORTED
-#     define READ_BDHI 4
-#     define DO_16BIT
-#  endif
-#else
-#  define WRITE_BDHI 3
-#endif
-#ifndef DO_16BIT
-#  define READ_BDHI 3
-#endif
-
-static int
-next_format(png_bytep colour_type, png_bytep bit_depth)
-{
-   if (*bit_depth == 0)
-   {
-      *colour_type = 0, *bit_depth = 1;
-      return 1;
-   }
-
-   *bit_depth = (png_byte)(*bit_depth << 1);
-
-   /* Palette images are restricted to 8 bit depth */
-   if (*bit_depth <= 8
-#     ifdef DO_16BIT
-         || (*colour_type != 3 && *bit_depth <= 16)
-#     endif
-      )
-      return 1;
-
-   /* Move to the next color type, or return 0 at the end. */
-   switch (*colour_type)
-   {
-      case 0:
-         *colour_type = 2;
-         *bit_depth = 8;
-         return 1;
-
-      case 2:
-         *colour_type = 3;
-         *bit_depth = 1;
-         return 1;
-
-      case 3:
-         *colour_type = 4;
-         *bit_depth = 8;
-         return 1;
-
-      case 4:
-         *colour_type = 6;
-         *bit_depth = 8;
-         return 1;
-
-      default:
-         return 0;
-   }
-}
-
-static unsigned int
-sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
-    png_uint_32 x, unsigned int sample_index)
-{
-   png_uint_32 bit_index, result;
-
-   /* Find a sample index for the desired sample: */
-   x *= bit_depth;
-   bit_index = x;
-
-   if ((colour_type & 1) == 0) /* !palette */
-   {
-      if (colour_type & 2)
-         bit_index *= 3;
-
-      if (colour_type & 4)
-         bit_index += x; /* Alpha channel */
-
-      if (colour_type & (2+4))
-         bit_index += sample_index * bit_depth; /* Multiple channels: select one */
-   }
-
-   /* Return the sample from the row as an integer. */
-   row += bit_index >> 3;
-   result = *row;
-
-   if (bit_depth == 8)
-      return result;
-
-   else if (bit_depth > 8)
-      return (result << 8) + *++row;
-
-   /* Less than 8 bits per sample. */
-   bit_index &= 7;
-   return (result >> (8-bit_index-bit_depth)) & ((1U<<bit_depth)-1);
-}
-
-/* Copy a single pixel, of a given size, from one buffer to another -
- * while this is basically bit addressed there is an implicit assumption
- * that pixels 8 or more bits in size are byte aligned and that pixels
- * do not otherwise cross byte boundaries.  (This is, so far as I know,
- * universally true in bitmap computer graphics.  [JCB 20101212])
- *
- * NOTE: The to and from buffers may be the same.
- */
-static void
-pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
-   png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize)
-{
-   /* Assume we can multiply by 'size' without overflow because we are
-    * just working in a single buffer.
-    */
-   toIndex *= pixelSize;
-   fromIndex *= pixelSize;
-   if (pixelSize < 8) /* Sub-byte */
-   {
-      /* Mask to select the location of the copied pixel: */
-      unsigned int destMask = ((1U<<pixelSize)-1) << (8-pixelSize-(toIndex&7));
-      /* The following read the entire pixels and clears the extra: */
-      unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
-      unsigned int sourceByte = fromBuffer[fromIndex >> 3];
-
-      /* Don't rely on << or >> supporting '0' here, just in case: */
-      fromIndex &= 7;
-      if (fromIndex > 0) sourceByte <<= fromIndex;
-      if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
-
-      toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
-   }
-   else /* One or more bytes */
-      memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
-}
-
-/* Compare pixels - they are assumed to start at the first byte in the
- * given buffers.
- */
-static int
-pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
-{
-   if (memcmp(pa, pb, bit_width>>3) == 0)
-   {
-      png_uint_32 p;
-
-      if ((bit_width & 7) == 0) return 0;
-
-      /* Ok, any differences? */
-      p = pa[bit_width >> 3];
-      p ^= pb[bit_width >> 3];
-
-      if (p == 0) return 0;
-
-      /* There are, but they may not be significant, remove the bits
-       * after the end (the low order bits in PNG.)
-       */
-      bit_width &= 7;
-      p >>= 8-bit_width;
-
-      if (p == 0) return 0;
-   }
-
-   return 1; /* Different */
-}
-
-/*************************** BASIC PNG FILE WRITING ***************************/
-/* A png_store takes data from the sequential writer or provides data
- * to the sequential reader.  It can also store the result of a PNG
- * write for later retrieval.
- */
-#define STORE_BUFFER_SIZE 500 /* arbitrary */
-typedef struct png_store_buffer
-{
-   struct png_store_buffer*  prev;    /* NOTE: stored in reverse order */
-   png_byte                  buffer[STORE_BUFFER_SIZE];
-} png_store_buffer;
-
-#define FILE_NAME_SIZE 64
-
-typedef struct png_store_file
-{
-   struct png_store_file*  next;      /* as many as you like... */
-   char                    name[FILE_NAME_SIZE];
-   png_uint_32             id;        /* must be correct (see FILEID) */
-   png_size_t              datacount; /* In this (the last) buffer */
-   png_store_buffer        data;      /* Last buffer in file */
-} png_store_file;
-
-/* The following is a pool of memory allocated by a single libpng read or write
- * operation.
- */
-typedef struct store_pool
-{
-   struct png_store    *store;   /* Back pointer */
-   struct store_memory *list;    /* List of allocated memory */
-   png_byte             mark[4]; /* Before and after data */
-
-   /* Statistics for this run. */
-   png_alloc_size_t     max;     /* Maximum single allocation */
-   png_alloc_size_t     current; /* Current allocation */
-   png_alloc_size_t     limit;   /* Highest current allocation */
-   png_alloc_size_t     total;   /* Total allocation */
-
-   /* Overall statistics (retained across successive runs). */
-   png_alloc_size_t     max_max;
-   png_alloc_size_t     max_limit;
-   png_alloc_size_t     max_total;
-} store_pool;
-
-typedef struct png_store
-{
-   /* For cexcept.h exception handling - simply store one of these;
-    * the context is a self pointer but it may point to a different
-    * png_store (in fact it never does in this program.)
-    */
-   struct exception_context
-                      exception_context;
-
-   unsigned int       verbose :1;
-   unsigned int       treat_warnings_as_errors :1;
-   unsigned int       expect_error :1;
-   unsigned int       expect_warning :1;
-   unsigned int       saw_warning :1;
-   unsigned int       speed :1;
-   unsigned int       progressive :1; /* use progressive read */
-   unsigned int       validated :1;   /* used as a temporary flag */
-   int                nerrors;
-   int                nwarnings;
-   char               test[128]; /* Name of test */
-   char               error[256];
-
-   /* Read fields */
-   png_structp        pread;    /* Used to read a saved file */
-   png_infop          piread;
-   png_store_file*    current;  /* Set when reading */
-   png_store_buffer*  next;     /* Set when reading */
-   png_size_t         readpos;  /* Position in *next */
-   png_byte*          image;    /* Buffer for reading interlaced images */
-   size_t             cb_image; /* Size of this buffer */
-   store_pool         read_memory_pool;
-
-   /* Write fields */
-   png_store_file*    saved;
-   png_structp        pwrite;   /* Used when writing a new file */
-   png_infop          piwrite;
-   png_size_t         writepos; /* Position in .new */
-   char               wname[FILE_NAME_SIZE];
-   png_store_buffer   new;      /* The end of the new PNG file being written. */
-   store_pool         write_memory_pool;
-} png_store;
-
-/* Initialization and cleanup */
-static void
-store_pool_mark(png_byte *mark)
-{
-   /* Generate a new mark.  This uses a boring repeatable algorithm and it is
-    * implemented here so that it gives the same set of numbers on every
-    * architecture.  It's a linear congruential generator (Knuth or Sedgewick
-    * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
-    * Hill, "The Art of Electronics".
-    */
-   static png_uint_32 u0 = 0x12345678, u1 = 1;
-
-   /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
-    * bit-20.  The top 1 bit is in u1, the bottom 32 are in u0.
-    */
-   int i;
-   for (i=0; i<4; ++i)
-   {
-      /* First generate 8 new bits then shift them in at the end. */
-      png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
-      u1 <<= 8;
-      u1 |= u0 >> 24;
-      u0 <<= 8;
-      u0 |= u;
-      *mark++ = (png_byte)u;
-   }
-}
-
-/* Use this for random 32 bit values, this function makes sure the result is
- * non-zero.
- */
-static png_uint_32
-random_32(void)
-{
-
-   for(;;)
-   {
-      png_byte mark[4];
-      png_uint_32 result;
-
-      store_pool_mark(mark);
-      result = png_get_uint_32(mark);
-
-      if (result != 0)
-         return result;
-   }
-}
-
-static void
-store_pool_init(png_store *ps, store_pool *pool)
-{
-   memset(pool, 0, sizeof *pool);
-
-   pool->store = ps;
-   pool->list = NULL;
-   pool->max = pool->current = pool->limit = pool->total = 0;
-   pool->max_max = pool->max_limit = pool->max_total = 0;
-   store_pool_mark(pool->mark);
-}
-
-static void
-store_init(png_store* ps)
-{
-   memset(ps, 0, sizeof *ps);
-   init_exception_context(&ps->exception_context);
-   store_pool_init(ps, &ps->read_memory_pool);
-   store_pool_init(ps, &ps->write_memory_pool);
-   ps->verbose = 0;
-   ps->treat_warnings_as_errors = 0;
-   ps->expect_error = 0;
-   ps->expect_warning = 0;
-   ps->saw_warning = 0;
-   ps->speed = 0;
-   ps->progressive = 0;
-   ps->validated = 0;
-   ps->nerrors = ps->nwarnings = 0;
-   ps->pread = NULL;
-   ps->piread = NULL;
-   ps->saved = ps->current = NULL;
-   ps->next = NULL;
-   ps->readpos = 0;
-   ps->image = NULL;
-   ps->cb_image = 0;
-   ps->pwrite = NULL;
-   ps->piwrite = NULL;
-   ps->writepos = 0;
-   ps->new.prev = NULL;
-}
-
-/* This somewhat odd function is used when reading an image to ensure that the
- * buffer is big enough - this is why a png_structp is available.
- */
-static void
-store_ensure_image(png_store *ps, png_structp pp, size_t cb)
-{
-   if (ps->cb_image < cb)
-   {
-      if (ps->image != NULL)
-      {
-         free(ps->image-1);
-         ps->cb_image = 0;
-      }
-
-      /* The buffer is deliberately mis-aligned. */
-      ps->image = malloc(cb+1);
-      if (ps->image == NULL)
-         png_error(pp, "OOM allocating image buffer");
-
-      ++(ps->image);
-      ps->cb_image = cb;
-   }
-
-   /* And, for error checking, the whole buffer is set to '1' - this
-    * matches what happens with the 'size' test images on write and also
-    * matches the unused bits in the test rows.
-    */
-   memset(ps->image, 0xff, cb);
-}
-
-static void
-store_freebuffer(png_store_buffer* psb)
-{
-   if (psb->prev)
-   {
-      store_freebuffer(psb->prev);
-      free(psb->prev);
-      psb->prev = NULL;
-   }
-}
-
-static void
-store_freenew(png_store *ps)
-{
-   store_freebuffer(&ps->new);
-   ps->writepos = 0;
-}
-
-static void
-store_storenew(png_store *ps)
-{
-   png_store_buffer *pb;
-
-   if (ps->writepos != STORE_BUFFER_SIZE)
-      png_error(ps->pwrite, "invalid store call");
-
-   pb = malloc(sizeof *pb);
-
-   if (pb == NULL)
-      png_error(ps->pwrite, "store new: OOM");
-
-   *pb = ps->new;
-   ps->new.prev = pb;
-   ps->writepos = 0;
-}
-
-static void
-store_freefile(png_store_file **ppf)
-{
-   if (*ppf != NULL)
-   {
-      store_freefile(&(*ppf)->next);
-
-      store_freebuffer(&(*ppf)->data);
-      (*ppf)->datacount = 0;
-      free(*ppf);
-      *ppf = NULL;
-   }
-}
-
-/* Main interface to file storeage, after writing a new PNG file (see the API
- * below) call store_storefile to store the result with the given name and id.
- */
-static void
-store_storefile(png_store *ps, png_uint_32 id)
-{
-   png_store_file *pf = malloc(sizeof *pf);
-   if (pf == NULL)
-      png_error(ps->pwrite, "storefile: OOM");
-   safecat(pf->name, sizeof pf->name, 0, ps->wname);
-   pf->id = id;
-   pf->data = ps->new;
-   pf->datacount = ps->writepos;
-   ps->new.prev = NULL;
-   ps->writepos = 0;
-
-   /* And save it. */
-   pf->next = ps->saved;
-   ps->saved = pf;
-}
-
-/* Generate an error message (in the given buffer) */
-static size_t
-store_message(png_store *ps, png_structp pp, char *buffer, size_t bufsize,
-   size_t pos, PNG_CONST char *msg)
-{
-   if (pp != NULL && pp == ps->pread)
-   {
-      /* Reading a file */
-      pos = safecat(buffer, bufsize, pos, "read: ");
-
-      if (ps->current != NULL)
-      {
-         pos = safecat(buffer, bufsize, pos, ps->current->name);
-         pos = safecat(buffer, bufsize, pos, sep);
-      }
-   }
-
-   else if (pp != NULL && pp == ps->pwrite)
-   {
-      /* Writing a file */
-      pos = safecat(buffer, bufsize, pos, "write: ");
-      pos = safecat(buffer, bufsize, pos, ps->wname);
-      pos = safecat(buffer, bufsize, pos, sep);
-   }
-
-   else
-   {
-      /* Neither reading nor writing (or a memory error in struct delete) */
-      pos = safecat(buffer, bufsize, pos, "pngvalid: ");
-   }
-
-   if (ps->test[0] != 0)
-   {
-      pos = safecat(buffer, bufsize, pos, ps->test);
-      pos = safecat(buffer, bufsize, pos, sep);
-   }
-   pos = safecat(buffer, bufsize, pos, msg);
-   return pos;
-}
-
-/* Log an error or warning - the relevant count is always incremented. */
-static void
-store_log(png_store* ps, png_structp pp, png_const_charp message, int is_error)
-{
-   /* The warning is copied to the error buffer if there are no errors and it is
-    * the first warning.  The error is copied to the error buffer if it is the
-    * first error (overwriting any prior warnings).
-    */
-   if (is_error ? (ps->nerrors)++ == 0 :
-       (ps->nwarnings)++ == 0 && ps->nerrors == 0)
-      store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
-
-   if (ps->verbose)
-   {
-      char buffer[256];
-      size_t pos;
-
-      if (is_error)
-         pos = safecat(buffer, sizeof buffer, 0, "error: ");
-      else
-         pos = safecat(buffer, sizeof buffer, 0, "warning: ");
-
-      store_message(ps, pp, buffer, sizeof buffer, pos, message);
-      fputs(buffer, stderr);
-      fputc('\n', stderr);
-   }
-}
-
-/* Functions to use as PNG callbacks. */
-static void
-store_error(png_structp pp, png_const_charp message) /* PNG_NORETURN */
-{
-   png_store *ps = png_get_error_ptr(pp);
-
-   if (!ps->expect_error)
-      store_log(ps, pp, message, 1 /* error */);
-
-   /* And finally throw an exception. */
-   {
-      struct exception_context *the_exception_context = &ps->exception_context;
-      Throw ps;
-   }
-}
-
-static void
-store_warning(png_structp pp, png_const_charp message)
-{
-   png_store *ps = png_get_error_ptr(pp);
-
-   if (!ps->expect_warning)
-      store_log(ps, pp, message, 0 /* warning */);
-   else
-      ps->saw_warning = 1;
-}
-
-static void
-store_write(png_structp pp, png_bytep pb, png_size_t st)
-{
-   png_store *ps = png_get_io_ptr(pp);
-
-   if (ps->pwrite != pp)
-      png_error(pp, "store state damaged");
-
-   while (st > 0)
-   {
-      size_t cb;
-
-      if (ps->writepos >= STORE_BUFFER_SIZE)
-         store_storenew(ps);
-
-      cb = st;
-
-      if (cb > STORE_BUFFER_SIZE - ps->writepos)
-         cb = STORE_BUFFER_SIZE - ps->writepos;
-
-      memcpy(ps->new.buffer + ps->writepos, pb, cb);
-      pb += cb;
-      st -= cb;
-      ps->writepos += cb;
-   }
-}
-
-static void
-store_flush(png_structp pp)
-{
-   UNUSED(pp) /*DOES NOTHING*/
-}
-
-static size_t
-store_read_buffer_size(png_store *ps)
-{
-   /* Return the bytes available for read in the current buffer. */
-   if (ps->next != &ps->current->data)
-      return STORE_BUFFER_SIZE;
-
-   return ps->current->datacount;
-}
-
-/* Return total bytes available for read. */
-static size_t
-store_read_buffer_avail(png_store *ps)
-{
-   if (ps->current != NULL && ps->next != NULL)
-   {
-      png_store_buffer *next = &ps->current->data;
-      size_t cbAvail = ps->current->datacount;
-
-      while (next != ps->next && next != NULL)
-      {
-         next = next->prev;
-         cbAvail += STORE_BUFFER_SIZE;
-      }
-
-      if (next != ps->next)
-         png_error(ps->pread, "buffer read error");
-
-      if (cbAvail > ps->readpos)
-         return cbAvail - ps->readpos;
-   }
-
-   return 0;
-}
-
-static int
-store_read_buffer_next(png_store *ps)
-{
-   png_store_buffer *pbOld = ps->next;
-   png_store_buffer *pbNew = &ps->current->data;
-   if (pbOld != pbNew)
-   {
-      while (pbNew != NULL && pbNew->prev != pbOld)
-         pbNew = pbNew->prev;
-
-      if (pbNew != NULL)
-      {
-         ps->next = pbNew;
-         ps->readpos = 0;
-         return 1;
-      }
-
-      png_error(ps->pread, "buffer lost");
-   }
-
-   return 0; /* EOF or error */
-}
-
-/* Need separate implementation and callback to allow use of the same code
- * during progressive read, where the io_ptr is set internally by libpng.
- */
-static void
-store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
-{
-   if (ps->current == NULL || ps->next == NULL)
-      png_error(ps->pread, "store state damaged");
-
-   while (st > 0)
-   {
-      size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
-
-      if (cbAvail > 0)
-      {
-         if (cbAvail > st) cbAvail = st;
-         memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
-         st -= cbAvail;
-         pb += cbAvail;
-         ps->readpos += cbAvail;
-      }
-
-      else if (!store_read_buffer_next(ps))
-         png_error(ps->pread, "read beyond end of file");
-   }
-}
-
-static void
-store_read(png_structp pp, png_bytep pb, png_size_t st)
-{
-   png_store *ps = png_get_io_ptr(pp);
-
-   if (ps == NULL || ps->pread != pp)
-      png_error(pp, "bad store read call");
-
-   store_read_imp(ps, pb, st);
-}
-
-static void
-store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
-{
-   /* Notice that a call to store_read will cause this function to fail because
-    * readpos will be set.
-    */
-   if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
-      png_error(pp, "store state damaged (progressive)");
-
-   do
-   {
-      if (ps->readpos != 0)
-         png_error(pp, "store_read called during progressive read");
-
-      png_process_data(pp, pi, ps->next->buffer, store_read_buffer_size(ps));
-   }
-   while (store_read_buffer_next(ps));
-}
-
-/***************************** MEMORY MANAGEMENT*** ***************************/
-/* A store_memory is simply the header for an allocated block of memory.  The
- * pointer returned to libpng is just after the end of the header block, the
- * allocated memory is followed by a second copy of the 'mark'.
- */
-typedef struct store_memory
-{
-   store_pool          *pool;    /* Originating pool */
-   struct store_memory *next;    /* Singly linked list */
-   png_alloc_size_t     size;    /* Size of memory allocated */
-   png_byte             mark[4]; /* ID marker */
-} store_memory;
-
-/* Handle a fatal error in memory allocation.  This calls png_error if the
- * libpng struct is non-NULL, else it outputs a message and returns.  This means
- * that a memory problem while libpng is running will abort (png_error) the
- * handling of particular file while one in cleanup (after the destroy of the
- * struct has returned) will simply keep going and free (or attempt to free)
- * all the memory.
- */
-static void
-store_pool_error(png_store *ps, png_structp pp, PNG_CONST char *msg)
-{
-   if (pp != NULL)
-      png_error(pp, msg);
-
-   /* Else we have to do it ourselves.  png_error eventually calls store_log,
-    * above.  store_log accepts a NULL png_structp - it just changes what gets
-    * output by store_message.
-    */
-   store_log(ps, pp, msg, 1 /* error */);
-}
-
-static void
-store_memory_free(png_structp pp, store_pool *pool, store_memory *memory)
-{
-   /* Note that pp may be NULL (see store_pool_delete below), the caller has
-    * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
-    * pointer (for sure), but the contents may have been trashed.
-    */
-   if (memory->pool != pool)
-      store_pool_error(pool->store, pp, "memory corrupted (pool)");
-
-   else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
-      store_pool_error(pool->store, pp, "memory corrupted (start)");
-
-   /* It should be safe to read the size field now. */
-   else
-   {
-      png_alloc_size_t cb = memory->size;
-
-      if (cb > pool->max)
-         store_pool_error(pool->store, pp, "memory corrupted (size)");
-
-      else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
-         != 0)
-         store_pool_error(pool->store, pp, "memory corrupted (end)");
-
-      /* Finally give the library a chance to find problems too: */
-      else
-         {
-         pool->current -= cb;
-         free(memory);
-         }
-   }
-}
-
-static void
-store_pool_delete(png_store *ps, store_pool *pool)
-{
-   if (pool->list != NULL)
-   {
-      fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
-         pool == &ps->read_memory_pool ? "read" : "write",
-         pool == &ps->read_memory_pool ? (ps->current != NULL ?
-            ps->current->name : "unknown file") : ps->wname);
-      ++ps->nerrors;
-
-      do
-      {
-         store_memory *next = pool->list;
-         pool->list = next->next;
-         next->next = NULL;
-
-         fprintf(stderr, "\t%lu bytes @ %p\n",
-             (unsigned long)next->size, next+1);
-         /* The NULL means this will always return, even if the memory is
-          * corrupted.
-          */
-         store_memory_free(NULL, pool, next);
-      }
-      while (pool->list != NULL);
-   }
-
-   /* And reset the other fields too for the next time. */
-   if (pool->max > pool->max_max) pool->max_max = pool->max;
-   pool->max = 0;
-   if (pool->current != 0) /* unexpected internal error */
-      fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
-         ps->test, pool == &ps->read_memory_pool ? "read" : "write",
-         pool == &ps->read_memory_pool ? (ps->current != NULL ?
-            ps->current->name : "unknown file") : ps->wname);
-   pool->current = 0;
-
-   if (pool->limit > pool->max_limit)
-      pool->max_limit = pool->limit;
-
-   pool->limit = 0;
-
-   if (pool->total > pool->max_total)
-      pool->max_total = pool->total;
-
-   pool->total = 0;
-
-   /* Get a new mark too. */
-   store_pool_mark(pool->mark);
-}
-
-/* The memory callbacks: */
-static png_voidp
-store_malloc(png_structp pp, png_alloc_size_t cb)
-{
-   store_pool *pool = png_get_mem_ptr(pp);
-   store_memory *new = malloc(cb + (sizeof *new) + (sizeof pool->mark));
-
-   if (new != NULL)
-   {
-      if (cb > pool->max)
-         pool->max = cb;
-
-      pool->current += cb;
-
-      if (pool->current > pool->limit)
-         pool->limit = pool->current;
-
-      pool->total += cb;
-
-      new->size = cb;
-      memcpy(new->mark, pool->mark, sizeof new->mark);
-      memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
-      new->pool = pool;
-      new->next = pool->list;
-      pool->list = new;
-      ++new;
-   }
-
-   else
-      store_pool_error(pool->store, pp, "out of memory");
-
-   return new;
-}
-
-static void
-store_free(png_structp pp, png_voidp memory)
-{
-   store_pool *pool = png_get_mem_ptr(pp);
-   store_memory *this = memory, **test;
-
-   /* First check that this 'memory' really is valid memory - it must be in the
-    * pool list.  If it is, use the shared memory_free function to free it.
-    */
-   --this;
-   for (test = &pool->list; *test != this; test = &(*test)->next)
-   {
-      if (*test == NULL)
-      {
-         store_pool_error(pool->store, pp, "bad pointer to free");
-         return;
-      }
-   }
-
-   /* Unlink this entry, *test == this. */
-   *test = this->next;
-   this->next = NULL;
-   store_memory_free(pp, pool, this);
-}
-
-/* Setup functions. */
-/* Cleanup when aborting a write or after storing the new file. */
-static void
-store_write_reset(png_store *ps)
-{
-   if (ps->pwrite != NULL)
-   {
-      anon_context(ps);
-
-      Try
-         png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
-
-      Catch_anonymous
-      {
-         /* memory corruption: continue. */
-      }
-
-      ps->pwrite = NULL;
-      ps->piwrite = NULL;
-   }
-
-   /* And make sure that all the memory has been freed - this will output
-    * spurious errors in the case of memory corruption above, but this is safe.
-    */
-   store_pool_delete(ps, &ps->write_memory_pool);
-
-   store_freenew(ps);
-}
-
-/* The following is the main write function, it returns a png_struct and,
- * optionally, a png_info suitable for writiing a new PNG file.  Use
- * store_storefile above to record this file after it has been written.  The
- * returned libpng structures as destroyed by store_write_reset above.
- */
-static png_structp
-set_store_for_write(png_store *ps, png_infopp ppi,
-   PNG_CONST char * volatile name)
-{
-   anon_context(ps);
-
-   Try
-   {
-      if (ps->pwrite != NULL)
-         png_error(ps->pwrite, "write store already in use");
-
-      store_write_reset(ps);
-      safecat(ps->wname, sizeof ps->wname, 0, name);
-
-      /* Don't do the slow memory checks if doing a speed test. */
-      if (ps->speed)
-         ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
-            ps, store_error, store_warning);
-
-      else
-         ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
-            ps, store_error, store_warning, &ps->write_memory_pool,
-            store_malloc, store_free);
-
-      png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
-
-      if (ppi != NULL)
-         *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
-   }
-
-   Catch_anonymous
-      return NULL;
-
-   return ps->pwrite;
-}
-
-/* Cleanup when finished reading (either due to error or in the success case).
- */
-static void
-store_read_reset(png_store *ps)
-{
-   if (ps->pread != NULL)
-   {
-      anon_context(ps);
-
-      Try
-         png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
-
-      Catch_anonymous
-      {
-         /* error already output: continue */
-      }
-
-      ps->pread = NULL;
-      ps->piread = NULL;
-   }
-
-   /* Always do this to be safe. */
-   store_pool_delete(ps, &ps->read_memory_pool);
-
-   ps->current = NULL;
-   ps->next = NULL;
-   ps->readpos = 0;
-   ps->validated = 0;
-}
-
-static void
-store_read_set(png_store *ps, png_uint_32 id)
-{
-   png_store_file *pf = ps->saved;
-
-   while (pf != NULL)
-   {
-      if (pf->id == id)
-      {
-         ps->current = pf;
-         ps->next = NULL;
-         store_read_buffer_next(ps);
-         return;
-      }
-
-      pf = pf->next;
-   }
-
-      {
-      size_t pos;
-      char msg[FILE_NAME_SIZE+64];
-
-      pos = standard_name_from_id(msg, sizeof msg, 0, id);
-      pos = safecat(msg, sizeof msg, pos, ": file not found");
-      png_error(ps->pread, msg);
-      }
-}
-
-/* The main interface for reading a saved file - pass the id number of the file
- * to retrieve.  Ids must be unique or the earlier file will be hidden.  The API
- * returns a png_struct and, optionally, a png_info.  Both of these will be
- * destroyed by store_read_reset above.
- */
-static png_structp
-set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
-   PNG_CONST char *name)
-{
-   /* Set the name for png_error */
-   safecat(ps->test, sizeof ps->test, 0, name);
-
-   if (ps->pread != NULL)
-      png_error(ps->pread, "read store already in use");
-
-   store_read_reset(ps);
-
-   /* Both the create APIs can return NULL if used in their default mode
-    * (because there is no other way of handling an error because the jmp_buf
-    * by default is stored in png_struct and that has not been allocated!)
-    * However, given that store_error works correctly in these circumstances
-    * we don't ever expect NULL in this program.
-    */
-   if (ps->speed)
-      ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps,
-          store_error, store_warning);
-
-   else
-      ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
-          store_error, store_warning, &ps->read_memory_pool, store_malloc,
-          store_free);
-
-   if (ps->pread == NULL)
-   {
-      struct exception_context *the_exception_context = &ps->exception_context;
-
-      store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
-         1 /*error*/);
-
-      Throw ps;
-   }
-
-   store_read_set(ps, id);
-
-   if (ppi != NULL)
-      *ppi = ps->piread = png_create_info_struct(ps->pread);
-
-   return ps->pread;
-}
-
-/* The overall cleanup of a store simply calls the above then removes all the
- * saved files.  This does not delete the store itself.
- */
-static void
-store_delete(png_store *ps)
-{
-   store_write_reset(ps);
-   store_read_reset(ps);
-   store_freefile(&ps->saved);
-
-   if (ps->image != NULL)
-   {
-      free(ps->image-1);
-      ps->image = NULL;
-      ps->cb_image = 0;
-   }
-}
-
-/*********************** PNG FILE MODIFICATION ON READ ************************/
-/* Files may be modified on read.  The following structure contains a complete
- * png_store together with extra members to handle modification and a special
- * read callback for libpng.  To use this the 'modifications' field must be set
- * to a list of png_modification structures that actually perform the
- * modification, otherwise a png_modifier is functionally equivalent to a
- * png_store.  There is a special read function, set_modifier_for_read, which
- * replaces set_store_for_read.
- */
-typedef struct png_modifier
-{
-   png_store               this;             /* I am a png_store */
-   struct png_modification *modifications;   /* Changes to make */
-
-   enum modifier_state
-   {
-      modifier_start,                        /* Initial value */
-      modifier_signature,                    /* Have a signature */
-      modifier_IHDR                          /* Have an IHDR */
-   }                        state;           /* My state */
-
-   /* Information from IHDR: */
-   png_byte                 bit_depth;       /* From IHDR */
-   png_byte                 colour_type;     /* From IHDR */
-
-   /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
-    * other chunks to be inserted.
-    */
-   png_uint_32              pending_len;
-   png_uint_32              pending_chunk;
-
-   /* Test values */
-   double                  *gammas;
-   unsigned int             ngammas;
-
-   /* Lowest sbit to test (libpng fails for sbit < 8) */
-   png_byte                 sbitlow;
-
-   /* Error control - these are the limits on errors accepted by the gamma tests
-    * below.
-    */
-   double                   maxout8;  /* Maximum output value error */
-   double                   maxabs8;  /* Absolute sample error 0..1 */
-   double                   maxpc8;   /* Percentage sample error 0..100% */
-   double                   maxout16; /* Maximum output value error */
-   double                   maxabs16; /* Absolute sample error 0..1 */
-   double                   maxpc16;  /* Percentage sample error 0..100% */
-
-   /* Logged 8 and 16 bit errors ('output' values): */
-   double                   error_gray_2;
-   double                   error_gray_4;
-   double                   error_gray_8;
-   double                   error_gray_16;
-   double                   error_color_8;
-   double                   error_color_16;
-
-   /* Flags: */
-   /* Whether or not to interlace. */
-   int                      interlace_type :9; /* int, but must store '1' */
-
-   /* Run the standard tests? */
-   unsigned int             test_standard :1;
-
-   /* Run the odd-sized image and interlace read/write tests? */
-   unsigned int             test_size :1;
-
-   /* Run tests on reading with a combiniation of transforms, */
-   unsigned int             test_transform :1;
-
-   /* When to use the use_input_precision option: */
-   unsigned int             use_input_precision :1;
-   unsigned int             use_input_precision_sbit :1;
-   unsigned int             use_input_precision_16to8 :1;
-
-   /* Which gamma tests to run: */
-   unsigned int             test_gamma_threshold :1;
-   unsigned int             test_gamma_transform :1; /* main tests */
-   unsigned int             test_gamma_sbit :1;
-   unsigned int             test_gamma_strip16 :1;
-
-   unsigned int             log :1;   /* Log max error */
-
-   /* Buffer information, the buffer size limits the size of the chunks that can
-    * be modified - they must fit (including header and CRC) into the buffer!
-    */
-   size_t                   flush;           /* Count of bytes to flush */
-   size_t                   buffer_count;    /* Bytes in buffer */
-   size_t                   buffer_position; /* Position in buffer */
-   png_byte                 buffer[1024];
-} png_modifier;
-
-static double abserr(png_modifier *pm, png_byte bit_depth)
-{
-   return bit_depth == 16 ? pm->maxabs16 : pm->maxabs8;
-}
-
-static double pcerr(png_modifier *pm, png_byte bit_depth)
-{
-   return (bit_depth == 16 ? pm->maxpc16 : pm->maxpc8) * .01;
-}
-
-static double outerr(png_modifier *pm, png_byte bit_depth)
-{
-   /* There is a serious error in the 2 and 4 bit grayscale transform because
-    * the gamma table value (8 bits) is simply shifted, not rounded, so the
-    * error in 4 bit greyscale gamma is up to the value below.  This is a hack
-    * to allow pngvalid to succeed:
-    */
-   if (bit_depth == 2)
-      return .73182-.5;
-
-   if (bit_depth == 4)
-      return .90644-.5;
-
-   if (bit_depth == 16)
-     return pm->maxout16;
-
-   return pm->maxout8;
-}
-
-/* This returns true if the test should be stopped now because it has already
- * failed and it is running silently.
- */
-static int fail(png_modifier *pm)
-{
-   return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
-       (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
-}
-
-static void
-modifier_init(png_modifier *pm)
-{
-   memset(pm, 0, sizeof *pm);
-   store_init(&pm->this);
-   pm->modifications = NULL;
-   pm->state = modifier_start;
-   pm->sbitlow = 1U;
-   pm->maxout8 = pm->maxpc8 = pm->maxabs8 = 0;
-   pm->maxout16 = pm->maxpc16 = pm->maxabs16 = 0;
-   pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
-   pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
-   pm->interlace_type = PNG_INTERLACE_NONE;
-   pm->test_standard = 0;
-   pm->test_size = 0;
-   pm->test_transform = 0;
-   pm->use_input_precision = 0;
-   pm->use_input_precision_sbit = 0;
-   pm->use_input_precision_16to8 = 0;
-   pm->test_gamma_threshold = 0;
-   pm->test_gamma_transform = 0;
-   pm->test_gamma_sbit = 0;
-   pm->test_gamma_strip16 = 0;
-   pm->log = 0;
-
-   /* Rely on the memset for all the other fields - there are no pointers */
-}
-
-/* One modification structure must be provided for each chunk to be modified (in
- * fact more than one can be provided if multiple separate changes are desired
- * for a single chunk.)  Modifications include adding a new chunk when a
- * suitable chunk does not exist.
- *
- * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
- * or 'added' as appropriate if the modify_fn returns 1 (true).  If the
- * modify_fn is NULL the chunk is simply removed.
- */
-typedef struct png_modification
-{
-   struct png_modification *next;
-   png_uint_32              chunk;
-
-   /* If the following is NULL all matching chunks will be removed: */
-   int                    (*modify_fn)(struct png_modifier *pm,
-                               struct png_modification *me, int add);
-
-   /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
-    * found and modified (and there is a modify_fn) the modify_fn will be called
-    * to add the chunk before the relevant chunk.
-    */
-   png_uint_32              add;
-   unsigned int             modified :1;     /* Chunk was modified */
-   unsigned int             added    :1;     /* Chunk was added */
-   unsigned int             removed  :1;     /* Chunk was removed */
-} png_modification;
-
-static void modification_reset(png_modification *pmm)
-{
-   if (pmm != NULL)
-   {
-      pmm->modified = 0;
-      pmm->added = 0;
-      pmm->removed = 0;
-      modification_reset(pmm->next);
-   }
-}
-
-static void
-modification_init(png_modification *pmm)
-{
-   memset(pmm, 0, sizeof *pmm);
-   pmm->next = NULL;
-   pmm->chunk = 0;
-   pmm->modify_fn = NULL;
-   pmm->add = 0;
-   modification_reset(pmm);
-}
-
-static void
-modifier_reset(png_modifier *pm)
-{
-   store_read_reset(&pm->this);
-   pm->modifications = NULL;
-   pm->state = modifier_start;
-   pm->bit_depth = pm->colour_type = 0;
-   pm->pending_len = pm->pending_chunk = 0;
-   pm->flush = pm->buffer_count = pm->buffer_position = 0;
-}
-
-/* Convenience macros. */
-#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
-#define CHUNK_IHDR CHUNK(73,72,68,82)
-#define CHUNK_PLTE CHUNK(80,76,84,69)
-#define CHUNK_IDAT CHUNK(73,68,65,84)
-#define CHUNK_IEND CHUNK(73,69,78,68)
-#define CHUNK_cHRM CHUNK(99,72,82,77)
-#define CHUNK_gAMA CHUNK(103,65,77,65)
-#define CHUNK_sBIT CHUNK(115,66,73,84)
-#define CHUNK_sRGB CHUNK(115,82,71,66)
-
-/* The guts of modification are performed during a read. */
-static void
-modifier_crc(png_bytep buffer)
-{
-   /* Recalculate the chunk CRC - a complete chunk must be in
-    * the buffer, at the start.
-    */
-   uInt datalen = png_get_uint_32(buffer);
-   png_save_uint_32(buffer+datalen+8, crc32(0L, buffer+4, datalen+4));
-}
-
-static void
-modifier_setbuffer(png_modifier *pm)
-{
-   modifier_crc(pm->buffer);
-   pm->buffer_count = png_get_uint_32(pm->buffer)+12;
-   pm->buffer_position = 0;
-}
-
-/* Separate the callback into the actual implementation (which is passed the
- * png_modifier explicitly) and the callback, which gets the modifier from the
- * png_struct.
- */
-static void
-modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
-{
-   while (st > 0)
-   {
-      size_t cb;
-      png_uint_32 len, chunk;
-      png_modification *mod;
-
-      if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
-      {
-         static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
-         case modifier_start:
-            store_read_imp(&pm->this, pm->buffer, 8); /* size of signature. */
-            pm->buffer_count = 8;
-            pm->buffer_position = 0;
-
-            if (memcmp(pm->buffer, sign, 8) != 0)
-               png_error(pm->this.pread, "invalid PNG file signature");
-            pm->state = modifier_signature;
-            break;
-
-         case modifier_signature:
-            store_read_imp(&pm->this, pm->buffer, 13+12); /* size of IHDR */
-            pm->buffer_count = 13+12;
-            pm->buffer_position = 0;
-
-            if (png_get_uint_32(pm->buffer) != 13 ||
-                png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
-               png_error(pm->this.pread, "invalid IHDR");
-
-            /* Check the list of modifiers for modifications to the IHDR. */
-            mod = pm->modifications;
-            while (mod != NULL)
-            {
-               if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
-                   (*mod->modify_fn)(pm, mod, 0))
-                  {
-                  mod->modified = 1;
-                  modifier_setbuffer(pm);
-                  }
-
-               /* Ignore removal or add if IHDR! */
-               mod = mod->next;
-            }
-
-            /* Cache information from the IHDR (the modified one.) */
-            pm->bit_depth = pm->buffer[8+8];
-            pm->colour_type = pm->buffer[8+8+1];
-
-            pm->state = modifier_IHDR;
-            pm->flush = 0;
-            break;
-
-         case modifier_IHDR:
-         default:
-            /* Read a new chunk and process it until we see PLTE, IDAT or
-             * IEND.  'flush' indicates that there is still some data to
-             * output from the preceding chunk.
-             */
-            if ((cb = pm->flush) > 0)
-            {
-               if (cb > st) cb = st;
-               pm->flush -= cb;
-               store_read_imp(&pm->this, pb, cb);
-               pb += cb;
-               st -= cb;
-               if (st <= 0) return;
-            }
-
-            /* No more bytes to flush, read a header, or handle a pending
-             * chunk.
-             */
-            if (pm->pending_chunk != 0)
-            {
-               png_save_uint_32(pm->buffer, pm->pending_len);
-               png_save_uint_32(pm->buffer+4, pm->pending_chunk);
-               pm->pending_len = 0;
-               pm->pending_chunk = 0;
-            }
-            else
-               store_read_imp(&pm->this, pm->buffer, 8);
-
-            pm->buffer_count = 8;
-            pm->buffer_position = 0;
-
-            /* Check for something to modify or a terminator chunk. */
-            len = png_get_uint_32(pm->buffer);
-            chunk = png_get_uint_32(pm->buffer+4);
-
-            /* Terminators first, they may have to be delayed for added
-             * chunks
-             */
-            if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
-                chunk == CHUNK_IEND)
-            {
-               mod = pm->modifications;
-
-               while (mod != NULL)
-               {
-                  if ((mod->add == chunk ||
-                      (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
-                      mod->modify_fn != NULL && !mod->modified && !mod->added)
-                  {
-                     /* Regardless of what the modify function does do not run
-                      * this again.
-                      */
-                     mod->added = 1;
-
-                     if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
-                     {
-                        /* Reset the CRC on a new chunk */
-                        if (pm->buffer_count > 0)
-                           modifier_setbuffer(pm);
-
-                        else
-                           {
-                           pm->buffer_position = 0;
-                           mod->removed = 1;
-                           }
-
-                        /* The buffer has been filled with something (we assume)
-                         * so output this.  Pend the current chunk.
-                         */
-                        pm->pending_len = len;
-                        pm->pending_chunk = chunk;
-                        break; /* out of while */
-                     }
-                  }
-
-                  mod = mod->next;
-               }
-
-               /* Don't do any further processing if the buffer was modified -
-                * otherwise the code will end up modifying a chunk that was
-                * just added.
-                */
-               if (mod != NULL)
-                  break; /* out of switch */
-            }
-
-            /* If we get to here then this chunk may need to be modified.  To
-             * do this it must be less than 1024 bytes in total size, otherwise
-             * it just gets flushed.
-             */
-            if (len+12 <= sizeof pm->buffer)
-            {
-               store_read_imp(&pm->this, pm->buffer+pm->buffer_count,
-                   len+12-pm->buffer_count);
-               pm->buffer_count = len+12;
-
-               /* Check for a modification, else leave it be. */
-               mod = pm->modifications;
-               while (mod != NULL)
-               {
-                  if (mod->chunk == chunk)
-                  {
-                     if (mod->modify_fn == NULL)
-                     {
-                        /* Remove this chunk */
-                        pm->buffer_count = pm->buffer_position = 0;
-                        mod->removed = 1;
-                        break; /* Terminate the while loop */
-                     }
-
-                     else if ((*mod->modify_fn)(pm, mod, 0))
-                     {
-                        mod->modified = 1;
-                        /* The chunk may have been removed: */
-                        if (pm->buffer_count == 0)
-                        {
-                           pm->buffer_position = 0;
-                           break;
-                        }
-                        modifier_setbuffer(pm);
-                     }
-                  }
-
-                  mod = mod->next;
-               }
-            }
-
-            else
-               pm->flush = len+12 - pm->buffer_count; /* data + crc */
-
-            /* Take the data from the buffer (if there is any). */
-            break;
-      }
-
-      /* Here to read from the modifier buffer (not directly from
-       * the store, as in the flush case above.)
-       */
-      cb = pm->buffer_count - pm->buffer_position;
-
-      if (cb > st)
-         cb = st;
-
-      memcpy(pb, pm->buffer + pm->buffer_position, cb);
-      st -= cb;
-      pb += cb;
-      pm->buffer_position += cb;
-   }
-}
-
-/* The callback: */
-static void
-modifier_read(png_structp pp, png_bytep pb, png_size_t st)
-{
-   png_modifier *pm = png_get_io_ptr(pp);
-
-   if (pm == NULL || pm->this.pread != pp)
-      png_error(pp, "bad modifier_read call");
-
-   modifier_read_imp(pm, pb, st);
-}
-
-/* Like store_progressive_read but the data is getting changed as we go so we
- * need a local buffer.
- */
-static void
-modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
-{
-   if (pm->this.pread != pp || pm->this.current == NULL ||
-       pm->this.next == NULL)
-      png_error(pp, "store state damaged (progressive)");
-
-   /* This is another Horowitz and Hill random noise generator.  In this case
-    * the aim is to stress the progressive reader with truely horrible variable
-    * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
-    * is generated.  We could probably just count from 1 to 32767 and get as
-    * good a result.
-    */
-   for (;;)
-   {
-      static png_uint_32 noise = 1;
-      png_size_t cb, cbAvail;
-      png_byte buffer[512];
-
-      /* Generate 15 more bits of stuff: */
-      noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
-      cb = noise & 0x1ff;
-
-      /* Check that this number of bytes are available (in the current buffer.)
-       * (This doesn't quite work - the modifier might delete a chunk; unlikely
-       * but possible, it doesn't happen at present because the modifier only
-       * adds chunks to standard images.)
-       */
-      cbAvail = store_read_buffer_avail(&pm->this);
-      if (pm->buffer_count > pm->buffer_position)
-         cbAvail += pm->buffer_count - pm->buffer_position;
-
-      if (cb > cbAvail)
-      {
-         /* Check for EOF: */
-         if (cbAvail == 0)
-            break;
-
-         cb = cbAvail;
-      }
-
-      modifier_read_imp(pm, buffer, cb);
-      png_process_data(pp, pi, buffer, cb);
-   }
-
-   /* Check the invariants at the end (if this fails it's a problem in this
-    * file!)
-    */
-   if (pm->buffer_count > pm->buffer_position ||
-       pm->this.next != &pm->this.current->data ||
-       pm->this.readpos < pm->this.current->datacount)
-      png_error(pp, "progressive read implementation error");
-}
-
-/* Set up a modifier. */
-static png_structp
-set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
-    PNG_CONST char *name)
-{
-   /* Do this first so that the modifier fields are cleared even if an error
-    * happens allocating the png_struct.  No allocation is done here so no
-    * cleanup is required.
-    */
-   pm->state = modifier_start;
-   pm->bit_depth = 0;
-   pm->colour_type = 255;
-
-   pm->pending_len = 0;
-   pm->pending_chunk = 0;
-   pm->flush = 0;
-   pm->buffer_count = 0;
-   pm->buffer_position = 0;
-
-   return set_store_for_read(&pm->this, ppi, id, name);
-}
-
-/***************************** STANDARD PNG FILES *****************************/
-/* Standard files - write and save standard files. */
-/* There are two basic forms of standard images.  Those which attempt to have
- * all the possible pixel values (not possible for 16bpp images, but a range of
- * values are produced) and those which have a range of image sizes.  The former
- * are used for testing transforms, in particular gamma correction and bit
- * reduction and increase.  The latter are reserved for testing the behavior of
- * libpng with respect to 'odd' image sizes - particularly small images where
- * rows become 1 byte and interlace passes disappear.
- *
- * The first, most useful, set are the 'transform' images, the second set of
- * small images are the 'size' images.
- *
- * The transform files are constructed with rows which fit into a 1024 byte row
- * buffer.  This makes allocation easier below.  Further regardless of the file
- * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
- *
- * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
- * and with an ID derived from the colour type, bit depth and interlace type
- * as above (FILEID).  The width (128) and height (variable) are not stored in
- * the FILEID - instead the fields are set to 0, indicating a transform file.
- *
- * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
- * a maximum width of 16 pixels (for the 64bpp case.)  They also have a maximum
- * height of 16 rows.  The width and height are stored in the FILEID and, being
- * non-zero, indicate a size file.
- */
-
-/* The number of passes is related to the interlace type. There wass no libpng
- * API to determine this prior to 1.5, so we need an inquiry function:
- */
-static int
-npasses_from_interlace_type(png_structp pp, int interlace_type)
-{
-   switch (interlace_type)
-   {
-   default:
-      png_error(pp, "invalid interlace type");
-
-   case PNG_INTERLACE_NONE:
-      return 1;
-
-   case PNG_INTERLACE_ADAM7:
-      return PNG_INTERLACE_ADAM7_PASSES;
-   }
-}
-
-static unsigned int
-bit_size(png_structp pp, png_byte colour_type, png_byte bit_depth)
-{
-   switch (colour_type)
-   {
-      case 0:  return bit_depth;
-
-      case 2:  return 3*bit_depth;
-
-      case 3:  return bit_depth;
-
-      case 4:  return 2*bit_depth;
-
-      case 6:  return 4*bit_depth;
-
-      default: png_error(pp, "invalid color type");
-   }
-}
-
-#define TRANSFORM_WIDTH  128U
-#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
-#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
-#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
-
-/* So the maximum image sizes are as follows.  A 'transform' image may require
- * more than 65535 bytes.  The size images are a maximum of 2046 bytes.
- */
-#define TRANSFORM_IMAGEMAX (TRANSFORM_ROWMAX * (png_uint_32)2048)
-#define SIZE_IMAGEMAX (SIZE_ROWMAX * 16U)
-
-static size_t
-transform_rowsize(png_structp pp, png_byte colour_type, png_byte bit_depth)
-{
-   return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
-}
-
-/* transform_width(pp, colour_type, bit_depth) current returns the same number
- * every time, so just use a macro:
- */
-#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
-
-static png_uint_32
-transform_height(png_structp pp, png_byte colour_type, png_byte bit_depth)
-{
-   switch (bit_size(pp, colour_type, bit_depth))
-   {
-      case 1:
-      case 2:
-      case 4:
-         return 1;   /* Total of 128 pixels */
-
-      case 8:
-         return 2;   /* Total of 256 pixels/bytes */
-
-      case 16:
-         return 512; /* Total of 65536 pixels */
-
-      case 24:
-      case 32:
-         return 512; /* 65536 pixels */
-
-      case 48:
-      case 64:
-         return 2048;/* 4 x 65536 pixels. */
-
-      default:
-         return 0;   /* Error, will be caught later */
-   }
-}
-
-/* The following can only be defined here, now we have the definitions
- * of the transform image sizes.
- */
-static png_uint_32
-standard_width(png_structp pp, png_uint_32 id)
-{
-   png_uint_32 width = WIDTH_FROM_ID(id);
-   UNUSED(pp)
-
-   if (width == 0)
-      width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
-
-   return width;
-}
-
-static png_uint_32
-standard_height(png_structp pp, png_uint_32 id)
-{
-   png_uint_32 height = HEIGHT_FROM_ID(id);
-
-   if (height == 0)
-      height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
-
-   return height;
-}
-
-static png_uint_32
-standard_rowsize(png_structp pp, png_uint_32 id)
-{
-   png_uint_32 width = standard_width(pp, id);
-
-   /* This won't overflow: */
-   width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
-   return (width + 7) / 8;
-}
-
-static void
-transform_row(png_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
-   png_byte colour_type, png_byte bit_depth, png_uint_32 y)
-{
-   png_uint_32 v = y << 7;
-   png_uint_32 i = 0;
-
-   switch (bit_size(pp, colour_type, bit_depth))
-   {
-      case 1:
-         while (i<128/8) buffer[i] = v & 0xff, v += 17, ++i;
-         return;
-
-      case 2:
-         while (i<128/4) buffer[i] = v & 0xff, v += 33, ++i;
-         return;
-
-      case 4:
-         while (i<128/2) buffer[i] = v & 0xff, v += 65, ++i;
-         return;
-
-      case 8:
-         /* 256 bytes total, 128 bytes in each row set as follows: */
-         while (i<128) buffer[i] = v & 0xff, ++v, ++i;
-         return;
-
-      case 16:
-         /* Generate all 65536 pixel values in order, which includes the 8 bit
-          * GA case as well as the 16 bit G case.
-          */
-         while (i<128)
-            buffer[2*i] = (v>>8) & 0xff, buffer[2*i+1] = v & 0xff, ++v, ++i;
-
-         return;
-
-      case 24:
-         /* 65535 pixels, but rotate the values. */
-         while (i<128)
-         {
-            /* Three bytes per pixel, r, g, b, make b by r^g */
-            buffer[3*i+0] = (v >> 8) & 0xff;
-            buffer[3*i+1] = v & 0xff;
-            buffer[3*i+2] = ((v >> 8) ^ v) & 0xff;
-            ++v;
-            ++i;
-         }
-
-         return;
-
-      case 32:
-         /* 65535 pixels, r, g, b, a; just replicate */
-         while (i<128)
-         {
-            buffer[4*i+0] = (v >> 8) & 0xff;
-            buffer[4*i+1] = v & 0xff;
-            buffer[4*i+2] = (v >> 8) & 0xff;
-            buffer[4*i+3] = v & 0xff;
-            ++v;
-            ++i;
-         }
-
-         return;
-
-      case 48:
-         /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
-          * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
-          */
-         while (i<128)
-         {
-            png_uint_32 t = v++;
-            buffer[6*i+0] = (t >> 8) & 0xff;
-            buffer[6*i+1] = t & 0xff;
-            t *= 257;
-            buffer[6*i+2] = (t >> 8) & 0xff;
-            buffer[6*i+3] = t & 0xff;
-            t *= 17;
-            buffer[6*i+4] = (t >> 8) & 0xff;
-            buffer[6*i+5] = t & 0xff;
-            ++i;
-         }
-
-         return;
-
-      case 64:
-         /* As above in the 32 bit case. */
-         while (i<128)
-         {
-            png_uint_32 t = v++;
-            buffer[8*i+0] = (t >> 8) & 0xff;
-            buffer[8*i+1] = t & 0xff;
-            buffer[8*i+4] = (t >> 8) & 0xff;
-            buffer[8*i+5] = t & 0xff;
-            t *= 257;
-            buffer[8*i+2] = (t >> 8) & 0xff;
-            buffer[8*i+3] = t & 0xff;
-            buffer[8*i+6] = (t >> 8) & 0xff;
-            buffer[8*i+7] = t & 0xff;
-            ++i;
-         }
-         return;
-
-      default:
-         break;
-   }
-
-   png_error(pp, "internal error");
-}
-
-/* This is just to do the right cast - could be changed to a function to check
- * 'bd' but there isn't much point.
- */
-#define DEPTH(bd) ((png_byte)(1U << (bd)))
-
-/* Make a standardized image given a an image colour type, bit depth and
- * interlace type.  The standard images have a very restricted range of
- * rows and heights and are used for testing transforms rather than image
- * layout details.  See make_size_images below for a way to make images
- * that test odd sizes along with the libpng interlace handling.
- */
-static void
-make_transform_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
-    png_byte PNG_CONST bit_depth, int interlace_type, png_const_charp name)
-{
-   context(ps, fault);
-
-   Try
-   {
-      png_infop pi;
-      png_structp pp = set_store_for_write(ps, &pi, name);
-      png_uint_32 h;
-
-      /* In the event of a problem return control to the Catch statement below
-       * to do the clean up - it is not possible to 'return' directly from a Try
-       * block.
-       */
-      if (pp == NULL)
-         Throw ps;
-
-      h = transform_height(pp, colour_type, bit_depth);
-
-      png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth), h,
-         bit_depth, colour_type, interlace_type,
-         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
-      if (colour_type == 3) /* palette */
-      {
-         unsigned int i = 0;
-         png_color pal[256];
-
-         do
-            pal[i].red = pal[i].green = pal[i].blue = (png_byte)i;
-         while(++i < 256U);
-
-         png_set_PLTE(pp, pi, pal, 256);
-      }
-
-      png_write_info(pp, pi);
-
-      if (png_get_rowbytes(pp, pi) !=
-          transform_rowsize(pp, colour_type, bit_depth))
-         png_error(pp, "row size incorrect");
-
-      else
-      {
-         /* Somewhat confusingly this must be called *after* png_write_info
-          * because if it is called before, the information in *pp has not been
-          * updated to reflect the interlaced image.
-          */
-         int npasses = png_set_interlace_handling(pp);
-         int pass;
-
-         if (npasses != npasses_from_interlace_type(pp, interlace_type))
-            png_error(pp, "write: png_set_interlace_handling failed");
-
-         for (pass=0; pass<npasses; ++pass)
-         {
-            png_uint_32 y;
-
-            for (y=0; y<h; ++y)
-            {
-               png_byte buffer[TRANSFORM_ROWMAX];
-
-               transform_row(pp, buffer, colour_type, bit_depth, y);
-               png_write_row(pp, buffer);
-            }
-         }
-      }
-
-      png_write_end(pp, pi);
-
-      /* And store this under the appropriate id, then clean up. */
-      store_storefile(ps, FILEID(colour_type, bit_depth, interlace_type,
-         0, 0, 0));
-
-      store_write_reset(ps);
-   }
-
-   Catch(fault)
-   {
-      /* Use the png_store returned by the exception. This may help the compiler
-       * because 'ps' is not used in this branch of the setjmp.  Note that fault
-       * and ps will always be the same value.
-       */
-      store_write_reset(fault);
-   }
-}
-
-static void
-make_standard(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, int bdlo,
-    int PNG_CONST bdhi)
-{
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      int interlace_type;
-
-      for (interlace_type = PNG_INTERLACE_NONE;
-           interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
-      {
-         char name[FILE_NAME_SIZE];
-
-         standard_name(name, sizeof name, 0, colour_type, bdlo, interlace_type,
-            0, 0, 0);
-         make_transform_image(ps, colour_type, DEPTH(bdlo), interlace_type,
-            name);
-      }
-   }
-}
-
-static void
-make_transform_images(png_store *ps)
-{
-   /* This is in case of errors. */
-   safecat(ps->test, sizeof ps->test, 0, "make standard images");
-
-   /* Arguments are colour_type, low bit depth, high bit depth
-    */
-   make_standard(ps, 0, 0, WRITE_BDHI);
-   make_standard(ps, 2, 3, WRITE_BDHI);
-   make_standard(ps, 3, 0, 3 /*palette: max 8 bits*/);
-   make_standard(ps, 4, 3, WRITE_BDHI);
-   make_standard(ps, 6, 3, WRITE_BDHI);
-}
-
-/* The following two routines use the PNG interlace support macros from
- * png.h to interlace or deinterlace rows.
- */
-static void
-interlace_row(png_bytep buffer, png_const_bytep imageRow,
-   unsigned int pixel_size, png_uint_32 w, int pass)
-{
-   png_uint_32 xin, xout, xstep;
-
-   /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
-    * code is presented this way to make it easier to understand.  In practice
-    * consult the code in the libpng source to see other ways of doing this.
-    */
-   xin = PNG_PASS_START_COL(pass);
-   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
-
-   for (xout=0; xin<w; xin+=xstep)
-   {
-      pixel_copy(buffer, xout, imageRow, xin, pixel_size);
-      ++xout;
-   }
-}
-
-static void
-deinterlace_row(png_bytep buffer, png_const_bytep row,
-   unsigned int pixel_size, png_uint_32 w, int pass)
-{
-   /* The inverse of the above, 'row' is part of row 'y' of the output image,
-    * in 'buffer'.  The image is 'w' wide and this is pass 'pass', distribute
-    * the pixels of row into buffer and return the number written (to allow
-    * this to be checked).
-    */
-   png_uint_32 xin, xout, xstep;
-
-   xout = PNG_PASS_START_COL(pass);
-   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
-
-   for (xin=0; xout<w; xout+=xstep)
-   {
-      pixel_copy(buffer, xout, row, xin, pixel_size);
-      ++xin;
-   }
-}
-
-/* Build a single row for the 'size' test images, this fills in only the
- * first bit_width bits of the sample row.
- */
-static void
-size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
-{
-   /* height is in the range 1 to 16, so: */
-   y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
-   /* the following ensures bits are set in small images: */
-   y ^= 0xA5;
-
-   while (bit_width >= 8)
-      *buffer++ = (png_byte)y++, bit_width -= 8;
-
-   /* There may be up to 7 remaining bits, these go in the most significant
-    * bits of the byte.
-    */
-   if (bit_width > 0)
-   {
-      png_uint_32 mask = (1U<<(8-bit_width))-1;
-      *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
-   }
-}
-
-static void
-make_size_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
-    png_byte PNG_CONST bit_depth, int PNG_CONST interlace_type,
-    png_uint_32 PNG_CONST w, png_uint_32 PNG_CONST h,
-    int PNG_CONST do_interlace)
-{
-   context(ps, fault);
-
-   Try
-   {
-      png_infop pi;
-      png_structp pp;
-      unsigned int pixel_size;
-
-      /* Make a name and get an appropriate id for the store: */
-      char name[FILE_NAME_SIZE];
-      PNG_CONST png_uint_32 id = FILEID(colour_type, bit_depth, interlace_type,
-         w, h, do_interlace);
-
-      standard_name_from_id(name, sizeof name, 0, id);
-      pp = set_store_for_write(ps, &pi, name);
-
-      /* In the event of a problem return control to the Catch statement below
-       * to do the clean up - it is not possible to 'return' directly from a Try
-       * block.
-       */
-      if (pp == NULL)
-         Throw ps;
-
-      png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
-         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
-      /* Same palette as make_transform_image - I don' think there is any
-       * benefit from using a different one (JB 20101211)
-       */
-      if (colour_type == 3) /* palette */
-      {
-         unsigned int i = 0;
-         png_color pal[256];
-
-         do
-            pal[i].red = pal[i].green = pal[i].blue = (png_byte)i;
-         while(++i < 256U);
-
-         png_set_PLTE(pp, pi, pal, 256);
-      }
-
-      png_write_info(pp, pi);
-
-      /* Calculate the bit size, divide by 8 to get the byte size - this won't
-       * overflow because we know the w values are all small enough even for
-       * a system where 'unsigned int' is only 16 bits.
-       */
-      pixel_size = bit_size(pp, colour_type, bit_depth);
-      if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
-         png_error(pp, "row size incorrect");
-
-      else
-      {
-         int npasses = npasses_from_interlace_type(pp, interlace_type);
-         png_uint_32 y;
-         int pass;
-         png_byte image[16][SIZE_ROWMAX];
-
-         /* To help consistent error detection make the parts of this buffer
-          * that aren't set below all '1':
-          */
-         memset(image, 0xff, sizeof image);
-
-         if (!do_interlace && npasses != png_set_interlace_handling(pp))
-            png_error(pp, "write: png_set_interlace_handling failed");
-
-         /* Prepare the whole image first to avoid making it 7 times: */
-         for (y=0; y<h; ++y)
-            size_row(image[y], w * pixel_size, y);
-
-         for (pass=0; pass<npasses; ++pass)
-         {
-            /* The following two are for checking the macros: */
-            PNG_CONST png_uint_32 wPass = PNG_PASS_COLS(w, pass);
-
-            /* If do_interlace is set we don't call png_write_row for every
-             * row because some of them are empty.  In fact, for a 1x1 image,
-             * most of them are empty!
-             */
-            for (y=0; y<h; ++y)
-            {
-               png_const_bytep row = image[y];
-               png_byte tempRow[SIZE_ROWMAX];
-
-               /* If do_interlace *and* the image is interlaced we
-                * need a reduced interlace row, this may be reduced
-                * to empty.
-                */
-               if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
-               {
-                  /* The row must not be written if it doesn't exist, notice
-                   * that there are two conditions here, either the row isn't
-                   * ever in the pass or the row would be but isn't wide
-                   * enough to contribute any pixels.  In fact the wPass test
-                   * can be used to skip the whole y loop in this case.
-                   */
-                  if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
-                  {
-                     /* Set to all 1's for error detection (libpng tends to
-                      * set unset things to 0).
-                      */
-                     memset(tempRow, 0xff, sizeof tempRow);
-                     interlace_row(tempRow, row, pixel_size, w, pass);
-                     row = tempRow;
-                  }
-                  else
-                     continue;
-               }
-
-               /* Only get to here if the row has some pixels in it. */
-               png_write_row(pp, row);
-            }
-         }
-      }
-
-      png_write_end(pp, pi);
-
-      /* And store this under the appropriate id, then clean up. */
-      store_storefile(ps, id);
-
-      store_write_reset(ps);
-   }
-
-   Catch(fault)
-   {
-      /* Use the png_store returned by the exception. This may help the compiler
-       * because 'ps' is not used in this branch of the setjmp.  Note that fault
-       * and ps will always be the same value.
-       */
-      store_write_reset(fault);
-   }
-}
-
-static void
-make_size(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, int bdlo,
-    int PNG_CONST bdhi)
-{
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      png_uint_32 width;
-
-      for (width = 1; width <= 16; ++width)
-      {
-         png_uint_32 height;
-
-         for (height = 1; height <= 16; ++height)
-         {
-            /* The four combinations of DIY interlace and interlace or not -
-             * no interlace + DIY should be identical to no interlace with
-             * libpng doing it.
-             */
-            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
-               width, height, 0);
-            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
-               width, height, 1);
-            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
-               width, height, 0);
-            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
-               width, height, 1);
-         }
-      }
-   }
-}
-
-static void
-make_size_images(png_store *ps)
-{
-   /* This is in case of errors. */
-   safecat(ps->test, sizeof ps->test, 0, "make size images");
-
-   /* Arguments are colour_type, low bit depth, high bit depth
-    */
-   make_size(ps, 0, 0, WRITE_BDHI);
-   make_size(ps, 2, 3, WRITE_BDHI);
-   make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
-   make_size(ps, 4, 3, WRITE_BDHI);
-   make_size(ps, 6, 3, WRITE_BDHI);
-}
-
-/* Return a row based on image id and 'y' for checking: */
-static void
-standard_row(png_structp pp, png_byte std[STANDARD_ROWMAX], png_uint_32 id,
-   png_uint_32 y)
-{
-   if (WIDTH_FROM_ID(id) == 0)
-      transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
-   else
-      size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
-         DEPTH_FROM_ID(id)), y);
-}
-
-/* Tests - individual test cases */
-/* Like 'make_standard' but errors are deliberately introduced into the calls
- * to ensure that they get detected - it should not be possible to write an
- * invalid image with libpng!
- */
-static void
-sBIT0_error_fn(png_structp pp, png_infop pi)
-{
-   /* 0 is invalid... */
-   png_color_8 bad;
-   bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
-   png_set_sBIT(pp, pi, &bad);
-}
-
-static void
-sBIT_error_fn(png_structp pp, png_infop pi)
-{
-   png_byte bit_depth;
-   png_color_8 bad;
-
-   if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
-      bit_depth = 8;
-
-   else
-      bit_depth = png_get_bit_depth(pp, pi);
-
-   /* Now we know the bit depth we can easily generate an invalid sBIT entry */
-   bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
-      (png_byte)(bit_depth+1);
-   png_set_sBIT(pp, pi, &bad);
-}
-
-static PNG_CONST struct
-{
-   void          (*fn)(png_structp, png_infop);
-   PNG_CONST char *msg;
-   unsigned int    warning :1; /* the error is a warning... */
-} error_test[] =
-    {
-       { sBIT0_error_fn, "sBIT(0): failed to detect error", 1 },
-       { sBIT_error_fn, "sBIT(too big): failed to detect error", 1 },
-    };
-
-static void
-make_error(png_store* volatile ps, png_byte PNG_CONST colour_type,
-    png_byte bit_depth, int interlace_type, int test, png_const_charp name)
-{
-   context(ps, fault);
-
-   Try
-   {
-      png_structp pp;
-      png_infop pi;
-
-      pp = set_store_for_write(ps, &pi, name);
-
-      if (pp == NULL)
-         Throw ps;
-
-      png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth),
-         transform_height(pp, colour_type, bit_depth), bit_depth, colour_type,
-         interlace_type, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
-      if (colour_type == 3) /* palette */
-      {
-         unsigned int i = 0;
-         png_color pal[256];
-
-         do
-            pal[i].red = pal[i].green = pal[i].blue = (png_byte)i;
-         while(++i < 256U);
-
-         png_set_PLTE(pp, pi, pal, 256);
-      }
-
-      /* Time for a few errors, these are in various optional chunks, the
-       * standard tests test the standard chunks pretty well.
-       */
-#     define exception__prev exception_prev_1
-#     define exception__env exception_env_1
-      Try
-      {
-         /* Expect this to throw: */
-         ps->expect_error = !error_test[test].warning;
-         ps->expect_warning = error_test[test].warning;
-         ps->saw_warning = 0;
-         error_test[test].fn(pp, pi);
-
-         /* Normally the error is only detected here: */
-         png_write_info(pp, pi);
-
-         /* And handle the case where it was only a warning: */
-         if (ps->expect_warning && ps->saw_warning)
-            Throw ps;
-
-         /* If we get here there is a problem, we have success - no error or
-          * no warning - when we shouldn't have success.  Log an error.
-          */
-         store_log(ps, pp, error_test[test].msg, 1 /*error*/);
-      }
-
-      Catch (fault)
-         ps = fault; /* expected exit, make sure ps is not clobbered */
-#undef exception__prev
-#undef exception__env
-
-      /* And clear these flags */
-      ps->expect_error = 0;
-      ps->expect_warning = 0;
-
-      /* Now write the whole image, just to make sure that the detected, or
-       * undetected, errro has not created problems inside libpng.
-       */
-      if (png_get_rowbytes(pp, pi) !=
-          transform_rowsize(pp, colour_type, bit_depth))
-         png_error(pp, "row size incorrect");
-
-      else
-      {
-         png_uint_32 h = transform_height(pp, colour_type, bit_depth);
-         int npasses = png_set_interlace_handling(pp);
-         int pass;
-
-         if (npasses != npasses_from_interlace_type(pp, interlace_type))
-            png_error(pp, "write: png_set_interlace_handling failed");
-
-         for (pass=0; pass<npasses; ++pass)
-         {
-            png_uint_32 y;
-
-            for (y=0; y<h; ++y)
-            {
-               png_byte buffer[TRANSFORM_ROWMAX];
-
-               transform_row(pp, buffer, colour_type, bit_depth, y);
-               png_write_row(pp, buffer);
-            }
-         }
-      }
-
-      png_write_end(pp, pi);
-
-      /* The following deletes the file that was just written. */
-      store_write_reset(ps);
-   }
-
-   Catch(fault)
-   {
-      store_write_reset(fault);
-   }
-}
-
-static int
-make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
-    int bdlo, int PNG_CONST bdhi)
-{
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      int interlace_type;
-
-      for (interlace_type = PNG_INTERLACE_NONE;
-           interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
-      {
-         unsigned int test;
-         char name[FILE_NAME_SIZE];
-
-         standard_name(name, sizeof name, 0, colour_type, bdlo, interlace_type,
-            0, 0, 0);
-
-         for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test)
-         {
-            make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
-               test, name);
-
-            if (fail(pm))
-               return 0;
-         }
-      }
-   }
-
-   return 1; /* keep going */
-}
-
-static void
-perform_error_test(png_modifier *pm)
-{
-   /* Need to do this here because we just write in this test. */
-   safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
-
-   if (!make_errors(pm, 0, 0, WRITE_BDHI))
-      return;
-
-   if (!make_errors(pm, 2, 3, WRITE_BDHI))
-      return;
-
-   if (!make_errors(pm, 3, 0, 3))
-      return;
-
-   if (!make_errors(pm, 4, 3, WRITE_BDHI))
-      return;
-
-   if (!make_errors(pm, 6, 3, WRITE_BDHI))
-      return;
-}
-
-/* Because we want to use the same code in both the progressive reader and the
- * sequential reader it is necessary to deal with the fact that the progressive
- * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
- * must contain all the test parameters and all the local variables directly
- * accessible to the sequential reader implementation.
- *
- * The technique adopted is to reinvent part of what Dijkstra termed a
- * 'display'; an array of pointers to the stack frames of enclosing functions so
- * that a nested function definition can access the local (C auto) variables of
- * the functions that contain its definition.  In fact C provides the first
- * pointer (the local variables - the stack frame pointer) and the last (the
- * global variables - the BCPL global vector typically implemented as global
- * addresses), this code requires one more pointer to make the display - the
- * local variables (and function call parameters) of the function that actually
- * invokes either the progressive or sequential reader.
- *
- * Perhaps confusingly this technique is confounded with classes - the
- * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
- * A gamma_display is a standard_display, taking advantage of the ANSI-C
- * requirement that the pointer to the first member of a structure must be the
- * same as the pointer to the structure.  This allows us to reuse standard_
- * functions in the gamma test code; something that could not be done with
- * nested funtions!
- */
-typedef struct standard_palette_entry /* pngvalid format palette! */
-{
-   png_byte red;
-   png_byte green;
-   png_byte blue;
-   png_byte alpha;
-} standard_palette[256];
-
-typedef struct standard_display
-{
-   png_store*  ps;             /* Test parameters (passed to the function) */
-   png_byte    colour_type;
-   png_byte    bit_depth;
-   png_byte    red_sBIT;       /* Input data sBIT values. */
-   png_byte    green_sBIT;
-   png_byte    blue_sBIT;
-   png_byte    alpha_sBIT;
-   int         interlace_type;
-   png_uint_32 id;             /* Calculated file ID */
-   png_uint_32 w;              /* Width of image */
-   png_uint_32 h;              /* Height of image */
-   int         npasses;        /* Number of interlaced passes */
-   png_uint_32 pixel_size;     /* Width of one pixel in bits */
-   png_uint_32 bit_width;      /* Width of output row in bits */
-   size_t      cbRow;          /* Bytes in a row of the output image */
-   int         do_interlace;   /* Do interlacing internally */
-   int         is_transparent; /* Transparecy information was present. */
-   struct
-   {
-      png_uint_16 red;
-      png_uint_16 green;
-      png_uint_16 blue;
-   }           transparent;    /* The transparent color, if set. */
-   standard_palette
-               palette;
-} standard_display;
-
-static void
-standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
-   int do_interlace)
-{
-   dp->ps = ps;
-   dp->colour_type = COL_FROM_ID(id);
-   dp->bit_depth = DEPTH_FROM_ID(id);
-   dp->alpha_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
-      dp->bit_depth;
-   dp->interlace_type = INTERLACE_FROM_ID(id);
-   dp->id = id;
-   /* All the rest are filled in after the read_info: */
-   dp->w = 0;
-   dp->h = 0;
-   dp->npasses = 0;
-   dp->pixel_size = 0;
-   dp->bit_width = 0;
-   dp->cbRow = 0;
-   dp->do_interlace = do_interlace;
-   dp->is_transparent = 0;
-   /* Preset the transparent color to black: */
-   memset(&dp->transparent, 0, sizeof dp->transparent);
-   /* Preset the palette to full intensity/opaque througout: */
-   memset(dp->palette, 0xff, sizeof dp->palette);
-
-}
-
-/* Call this only if the colour type is 3 - PNG_COLOR_TYPE_PALETTE - otherwise
- * it will png_error out.  The API returns true if tRNS information was
- * present.
- */
-static int
-standard_palette_init(standard_palette palette, png_structp pp, png_infop pi)
-{
-   png_colorp pal;
-   png_bytep trans_alpha;
-   int num;
-
-   pal = 0;
-   num = -1;
-   if (png_get_PLTE(pp, pi, &pal, &num) & PNG_INFO_PLTE)
-   {
-      int i;
-
-      for (i=0; i<num; ++i)
-      {
-         palette[i].red = pal[i].red;
-         palette[i].green = pal[i].green;
-         palette[i].blue = pal[i].blue;
-      }
-
-      /* Mark the remainder of the entries with a flag value: */
-      for (; i<256; ++i)
-         palette[i].red = palette[i].green = palette[i].blue = 126;
-   }
-
-   else /* !png_get_PLTE */
-      png_error(pp, "validate: missing PLTE with color type 3");
-
-   trans_alpha = 0;
-   num = -1;
-   if (png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS)
-   {
-      int i;
-
-      /* Any of these are crash-worthy - given the implementation of
-       * png_get_tRNS up to 1.5 an app won't crash if it just checks the
-       * result above and fails to check that the variables it passed have
-       * actually been filled in!  Note that if the app were to pass the
-       * last, png_color_16p, variable too it couldn't rely on this.
-       */
-      if (trans_alpha == 0 || num <= 0 || num > 256)
-         png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
-
-      for (i=0; i<num; ++i)
-         palette[i].alpha = trans_alpha[i];
-
-      for (; i<256; ++i)
-         palette[i].alpha = 255;
-
-      return 1; /* transparency */
-   }
-
-   else
-   {
-      /* No transparency - just set the alpha channel to opaque. */
-      int i;
-
-      for (i=0; i<256; ++i)
-         palette[i].alpha = 255;
-
-      return 0; /* no transparency */
-   }
-}
-
-/* By passing a 'standard_display' the progressive callbacks can be used
- * directly by the sequential code, the functions suffixed "_imp" are the
- * implementations, the functions without the suffix are the callbacks.
- *
- * The code for the info callback is split into two because this callback calls
- * png_read_update_info or png_start_read_image and what gets called depends on
- * whether the info needs updating (we want to test both calls in pngvalid.)
- */
-static void
-standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
-{
-   if (png_get_bit_depth(pp, pi) != dp->bit_depth)
-      png_error(pp, "validate: bit depth changed");
-
-   if (png_get_color_type(pp, pi) != dp->colour_type)
-      png_error(pp, "validate: color type changed");
-
-   if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
-      png_error(pp, "validate: filter type changed");
-
-   if (png_get_interlace_type(pp, pi) != dp->interlace_type)
-      png_error(pp, "validate: interlacing changed");
-
-   if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
-      png_error(pp, "validate: compression type changed");
-
-   dp->w = png_get_image_width(pp, pi);
-
-   if (dp->w != standard_width(pp, dp->id))
-      png_error(pp, "validate: image width changed");
-
-   dp->h = png_get_image_height(pp, pi);
-
-   if (dp->h != standard_height(pp, dp->id))
-      png_error(pp, "validate: image height changed");
-
-   /* Record (but don't check at present) the input sBIT according to the colour
-    * type information.
-    */
-   {
-      png_color_8p sBIT = 0;
-
-      if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
-      {
-         int sBIT_invalid = 0;
-
-         if (sBIT == 0)
-            png_error(pp, "validate: unexpected png_get_sBIT result");
-
-         if (dp->colour_type & PNG_COLOR_MASK_COLOR)
-         {
-            if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->red_sBIT = sBIT->red;
-
-            if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->green_sBIT = sBIT->green;
-
-            if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->blue_sBIT = sBIT->blue;
-         }
-
-         else /* !COLOR */
-         {
-            if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
-         }
-
-         /* All 8 bits in tRNS for a palette image are significant - see the
-          * spec.
-          */
-         if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
-         {
-            if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
-               sBIT_invalid = 1;
-            else
-               dp->alpha_sBIT = sBIT->alpha;
-         }
-
-         if (sBIT_invalid)
-            png_error(pp, "validate: sBIT value out of range");
-      }
-   }
-
-   /* Important: this is validating the value *before* any transforms have been
-    * put in place.  It doesn't matter for the standard tests, where there are
-    * no transforms, but it does for other tests where rowbytes may change after
-    * png_read_update_info.
-    */
-   if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
-      png_error(pp, "validate: row size changed");
-
-   /* The palette is never read for non-palette images, even though it is valid
-    * - this could be changed.
-    */
-   if (dp->colour_type == 3) /* palette */
-   {
-      int i;
-
-      dp->is_transparent = standard_palette_init(dp->palette, pp, pi);
-
-      /* And validate the result. */
-      for (i=0; i<256; ++i)
-         if (dp->palette[i].red != i || dp->palette[i].green != i ||
-            dp->palette[i].blue != i)
-            png_error(pp, "validate: color type 3 PLTE chunk changed");
-   }
-
-   /* In any case always check for a tranparent color: */
-   {
-      png_color_16p trans_color = 0;
-
-      if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
-      {
-         if (trans_color == 0)
-            png_error(pp, "validate: unexpected png_get_tRNS (color) result");
-
-         switch (dp->colour_type)
-         {
-         case 0:
-            dp->transparent.red = dp->transparent.green = dp->transparent.blue =
-               trans_color->gray;
-            dp->is_transparent = 1;
-            break;
-
-         case 2:
-            dp->transparent.red = trans_color->red;
-            dp->transparent.green = trans_color->green;
-            dp->transparent.blue = trans_color->blue;
-            dp->is_transparent = 1;
-            break;
-
-         case 3:
-            /* Not expected because it should result in the array case
-             * above.
-             */
-            png_error(pp, "validate: unexpected png_get_tRNS result");
-            break;
-
-         default:
-            png_error(pp, "validate: invalid tRNS chunk with alpha image");
-         }
-      }
-   }
-
-   /* Read the number of passes - expected to match the value used when
-    * creating the image (interlaced or not).  This has the side effect of
-    * turning on interlace handling (if do_interlace is not set.)
-    */
-   dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
-   if (!dp->do_interlace && dp->npasses != png_set_interlace_handling(pp))
-      png_error(pp, "validate: file changed interlace type");
-
-   /* Caller calls png_read_update_info or png_start_read_image now, then calls
-    * part2.
-    */
-}
-
-/* This must be called *after* the png_read_update_info call to get the correct
- * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
- * image.
- */
-static void
-standard_info_part2(standard_display *dp, png_structp pp, png_infop pi,
-    int nImages)
-{
-   /* Record cbRow now that it can be found. */
-   dp->pixel_size = bit_size(pp, png_get_color_type(pp, pi),
-      png_get_bit_depth(pp, pi));
-   dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
-   dp->cbRow = png_get_rowbytes(pp, pi);
-
-   /* Validate the rowbytes here again. */
-   if (dp->cbRow != (dp->bit_width+7)/8)
-      png_error(pp, "bad png_get_rowbytes calculation");
-
-   /* Then ensure there is enough space for the output image(s). */
-   store_ensure_image(dp->ps, pp, nImages * dp->cbRow * dp->h);
-}
-
-static void
-standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
-    int nImages)
-{
-   /* Note that the validation routine has the side effect of turning on
-    * interlace handling in the subsequent code.
-    */
-   standard_info_part1(dp, pp, pi);
-
-   /* And the info callback has to call this (or png_read_update_info - see
-    * below in the png_modifier code for that variant.
-    */
-   png_start_read_image(pp);
-
-   /* Validate the height, width and rowbytes plus ensure that sufficient buffer
-    * exists for decoding the image.
-    */
-   standard_info_part2(dp, pp, pi, nImages);
-}
-
-static void
-standard_info(png_structp pp, png_infop pi)
-{
-   standard_display *dp = png_get_progressive_ptr(pp);
-
-   /* Call with nImages==1 because the progressive reader can only produce one
-    * image.
-    */
-   standard_info_imp(dp, pp, pi, 1 /*only one image*/);
-}
-
-static void
-progressive_row(png_structp pp, png_bytep new_row, png_uint_32 y, int pass)
-{
-   PNG_CONST standard_display *dp = png_get_progressive_ptr(pp);
-
-   /* When handling interlacing some rows will be absent in each pass, the
-    * callback still gets called, but with a NULL pointer.  This is checked
-    * in the 'else' clause below.  We need our own 'cbRow', but we can't call
-    * png_get_rowbytes because we got no info structure.
-    */
-   if (new_row != NULL)
-   {
-      png_bytep row;
-
-      /* In the case where the reader doesn't do the interlace it gives
-       * us the y in the sub-image:
-       */
-      if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
-         y = PNG_ROW_FROM_PASS_ROW(y, pass);
-
-      /* Validate this just in case. */
-      if (y >= dp->h)
-         png_error(pp, "invalid y to progressive row callback");
-
-      row = dp->ps->image + y * dp->cbRow;
-
-      /* Combine the new row into the old: */
-      if (dp->do_interlace)
-      {
-         if (dp->interlace_type == PNG_INTERLACE_ADAM7)
-            deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass);
-         else
-            memcpy(row, new_row, dp->cbRow);
-      }
-      else
-         png_progressive_combine_row(pp, row, new_row);
-   } else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
-      PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
-      PNG_PASS_COLS(dp->w, pass) > 0)
-      png_error(pp, "missing row in progressive de-interlacing");
-}
-
-static void
-sequential_row(standard_display *dp, png_structp pp, png_infop pi,
-    PNG_CONST png_bytep pImage, PNG_CONST png_bytep pDisplay)
-{
-   PNG_CONST int         npasses = dp->npasses;
-   PNG_CONST int         do_interlace = dp->do_interlace &&
-      dp->interlace_type == PNG_INTERLACE_ADAM7;
-   PNG_CONST png_uint_32 height = standard_height(pp, dp->id);
-   PNG_CONST png_uint_32 width = standard_width(pp, dp->id);
-   PNG_CONST size_t      cbRow = dp->cbRow;
-   int pass;
-
-   for (pass=0; pass<npasses; ++pass)
-   {
-      png_uint_32 y;
-      png_uint_32 wPass = PNG_PASS_COLS(width, pass);
-      png_bytep pRow1 = pImage;
-      png_bytep pRow2 = pDisplay;
-
-      for (y=0; y<height; ++y)
-      {
-         if (do_interlace)
-         {
-            /* wPass may be zero or this row may not be in this pass.
-             * png_read_row must not be called in either case.
-             */
-            if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
-            {
-               /* Read the row into a pair of temporary buffers, then do the
-                * merge here into the output rows.
-                */
-               png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
-
-               /* The following aids (to some extent) error detection - we can
-                * see where png_read_row wrote.  Use opposite values in row and
-                * display to make this easier.
-                */
-               memset(row, 0xff, sizeof row);
-               memset(display, 0, sizeof display);
-
-               png_read_row(pp, row, display);
-
-               if (pRow1 != NULL)
-                  deinterlace_row(pRow1, row, dp->pixel_size, dp->w, pass);
-
-               if (pRow2 != NULL)
-                  deinterlace_row(pRow2, display, dp->pixel_size, dp->w, pass);
-            }
-         }
-         else
-            png_read_row(pp, pRow1, pRow2);
-
-         if (pRow1 != NULL)
-            pRow1 += cbRow;
-
-         if (pRow2 != NULL)
-            pRow2 += cbRow;
-      }
-   }
-
-   /* And finish the read operation (only really necessary if the caller wants
-    * to find additional data in png_info from chunks after the last IDAT.)
-    */
-   png_read_end(pp, pi);
-}
-
-static void
-standard_row_validate(standard_display *dp, png_structp pp, png_const_bytep row,
-   png_const_bytep display, png_uint_32 y)
-{
-   png_byte std[STANDARD_ROWMAX];
-
-   memset(std, 0xff, sizeof std);
-   standard_row(pp, std, dp->id, y);
-
-   /* At the end both the 'row' and 'display' arrays should end up identical.
-    * In earlier passes 'row' will be partially filled in, with only the pixels
-    * that have been read so far, but 'display' will have those pixels
-    * replicated to fill the unread pixels while reading an interlaced image.
-    * The side effect inside the libpng sequential reader is that the 'row'
-    * array retains the correct values for unwritten pixels within the row
-    * bytes, while the 'display' array gets bits off the end of the image (in
-    * the last byte) trashed.  Unfortunately in the progressive reader the
-    * row bytes are always trashed, so we always do a pixel_cmp here even though
-    * a memcmp of all cbRow bytes will succeed for the sequential reader.
-    */
-   if (row != NULL && pixel_cmp(std, row, dp->bit_width) != 0)
-   {
-      char msg[64];
-      sprintf(msg, "PNG image row %d changed", y);
-      png_error(pp, msg);
-   }
-
-   /* In this case use pixel_cmp because we need to compare a partial
-    * byte at the end of the row if the row is not an exact multiple
-    * of 8 bits wide.
-    */
-   if (display != NULL && pixel_cmp(std, display, dp->bit_width) != 0)
-   {
-      char msg[64];
-      sprintf(msg, "display row %d changed", y);
-      png_error(pp, msg);
-   }
-}
-
-static void
-standard_image_validate(standard_display *dp, png_structp pp,
-   png_const_bytep pImage, png_const_bytep pDisplay)
-{
-   png_uint_32 y;
-
-   for (y=0; y<dp->h; ++y)
-   {
-      standard_row_validate(dp, pp, pImage, pDisplay, y);
-
-      if (pImage != NULL)
-         pImage += dp->cbRow;
-
-      if (pDisplay != NULL)
-         pDisplay += dp->cbRow;
-   }
-
-   /* This avoids false positives if the validation code is never called! */
-   dp->ps->validated = 1;
-}
-
-static void
-standard_end(png_structp pp, png_infop pi)
-{
-   standard_display *dp = png_get_progressive_ptr(pp);
-
-   UNUSED(pi)
-
-   /* Validate the image - progressive reading only produces one variant for
-    * interlaced images.
-    */
-   standard_image_validate(dp, pp, dp->ps->image, NULL);
-}
-
-/* A single test run checking the standard image to ensure it is not damaged. */
-static void
-standard_test(png_store* PNG_CONST psIn, png_uint_32 PNG_CONST id,
-   int do_interlace)
-{
-   standard_display d;
-   context(psIn, fault);
-
-   /* Set up the display (stack frame) variables from the arguments to the
-    * function and initialize the locals that are filled in later.
-    */
-   standard_display_init(&d, psIn, id, do_interlace);
-
-   /* Everything is protected by a Try/Catch.  The functions called also
-    * typically have local Try/Catch blocks.
-    */
-   Try
-   {
-      png_structp pp;
-      png_infop pi;
-
-      /* Get a png_struct for reading the image. This will throw an error if it
-       * fails, so we don't need to check the result.
-       */
-      pp = set_store_for_read(d.ps, &pi, d.id,
-         d.do_interlace ?  (d.ps->progressive ?
-            "pngvalid progressive deinterlacer" :
-            "pngvalid sequential deinterlacer") : (d.ps->progressive ?
-               "progressive reader" : "sequential reader"));
-
-      /* Introduce the correct read function. */
-      if (d.ps->progressive)
-      {
-         png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
-            standard_end);
-
-         /* Now feed data into the reader until we reach the end: */
-         store_progressive_read(d.ps, pp, pi);
-      }
-      else
-      {
-         /* Note that this takes the store, not the display. */
-         png_set_read_fn(pp, d.ps, store_read);
-
-         /* Check the header values: */
-         png_read_info(pp, pi);
-
-         /* The code tests both versions of the images that the sequential
-          * reader can produce.
-          */
-         standard_info_imp(&d, pp, pi, 2 /*images*/);
-
-         /* Need the total bytes in the image below; we can't get to this point
-          * unless the PNG file values have been checked against the expected
-          * values.
-          */
-         {
-            PNG_CONST png_bytep pImage = d.ps->image;
-            PNG_CONST png_bytep pDisplay = pImage + d.cbRow * d.h;
-
-            sequential_row(&d, pp, pi, pImage, pDisplay);
-
-            /* After the last pass loop over the rows again to check that the
-             * image is correct.
-             */
-            standard_image_validate(&d, pp, pImage, pDisplay);
-         }
-      }
-
-      /* Check for validation. */
-      if (!d.ps->validated)
-         png_error(pp, "image read failed silently");
-
-      /* Successful completion. */
-   }
-
-   Catch(fault)
-      d.ps = fault; /* make sure this hasn't been clobbered. */
-
-   /* In either case clean up the store. */
-   store_read_reset(d.ps);
-}
-
-static int
-test_standard(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
-    int bdlo, int PNG_CONST bdhi)
-{
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      int interlace_type;
-
-      for (interlace_type = PNG_INTERLACE_NONE;
-           interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
-      {
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
-            interlace_type, 0, 0, 0), 0/*do_interlace*/);
-
-         if (fail(pm))
-            return 0;
-      }
-   }
-
-   return 1; /* keep going */
-}
-
-static void
-perform_standard_test(png_modifier *pm)
-{
-   /* Test each colour type over the valid range of bit depths (expressed as
-    * log2(bit_depth) in turn, stop as soon as any error is detected.
-    */
-   if (!test_standard(pm, 0, 0, READ_BDHI))
-      return;
-
-   if (!test_standard(pm, 2, 3, READ_BDHI))
-      return;
-
-   if (!test_standard(pm, 3, 0, 3))
-      return;
-
-   if (!test_standard(pm, 4, 3, READ_BDHI))
-      return;
-
-   if (!test_standard(pm, 6, 3, READ_BDHI))
-      return;
-}
-
-
-/********************************** SIZE TESTS ********************************/
-static int
-test_size(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
-    int bdlo, int PNG_CONST bdhi)
-{
-   /* Run the tests on each combination.
-    *
-    * NOTE: on my 32 bit x86 each of the following blocks takes
-    * a total of 3.5 seconds if done across every combo of bit depth
-    * width and height.  This is a waste of time in practice, hence the
-    * hinc and winc stuff:
-    */
-   static PNG_CONST png_byte hinc[] = {1, 3, 11, 1, 5};
-   static PNG_CONST png_byte winc[] = {1, 9, 5, 7, 1};
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      png_uint_32 h, w;
-
-      for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
-      {
-         /* First test all the 'size' images against the sequential
-          * reader using libpng to deinterlace (where required.)  This
-          * validates the write side of libpng.  There are four possibilities
-          * to validate.
-          */
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
-            PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/);
-
-         if (fail(pm))
-            return 0;
-
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
-            PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/);
-
-         if (fail(pm))
-            return 0;
-
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
-            PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/);
-
-         if (fail(pm))
-            return 0;
-
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
-            PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/);
-
-         if (fail(pm))
-            return 0;
-
-         /* Now validate the interlaced read side - do_interlace true,
-          * in the progressive case this does actually make a difference
-          * to the code used in the non-interlaced case too.
-          */
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
-            PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/);
-
-         if (fail(pm))
-            return 0;
-
-         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
-            PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/);
-
-         if (fail(pm))
-            return 0;
-      }
-   }
-
-   return 1; /* keep going */
-}
-
-static void
-perform_size_test(png_modifier *pm)
-{
-   /* Test each colour type over the valid range of bit depths (expressed as
-    * log2(bit_depth) in turn, stop as soon as any error is detected.
-    */
-   if (!test_size(pm, 0, 0, READ_BDHI))
-      return;
-
-   if (!test_size(pm, 2, 3, READ_BDHI))
-      return;
-
-   /* For the moment don't do the palette test - it's a waste of time when
-    * compared to the greyscale test.
-    */
-#if 0
-   if (!test_size(pm, 3, 0, 3))
-      return;
-#endif
-
-   if (!test_size(pm, 4, 3, READ_BDHI))
-      return;
-
-   if (!test_size(pm, 6, 3, READ_BDHI))
-      return;
-}
-
-
-/******************************* TRANSFORM TESTS ******************************/
-/* A set of tests to validate libpng image transforms.  The possibilities here
- * are legion because the transforms can be combined in a combinatorial
- * fashion.  To deal with this some measure of restraint is required, otherwise
- * the tests would take forever.
- */
-typedef struct image_pixel
-{
-   /* A local (pngvalid) representation of a PNG pixel, in all its
-    * various forms.
-    */
-   unsigned int red, green, blue, alpha; /* For non-palette images. */
-   unsigned int palette_index;           /* For a palette image. */
-   png_byte colour_type;                 /* As in the spec. */
-   png_byte bit_depth;                   /* Defines bit size in row */
-   png_byte sample_depth;                /* Scale of samples */
-   int      have_tRNS;                   /* tRNS chunk may need processing */
-
-   /* For checking the code calculates double precision floating point values
-    * along with an error value, accumulated from the transforms.  Because an
-    * sBIT setting allows larger error bounds (indeed, by the spec, apparently
-    * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
-    * channel is stored.  This sBIT value is folded in to the stored error value
-    * at the end of the application of the transforms to the pixel.
-    */
-   double   redf, greenf, bluef, alphaf;
-   double   rede, greene, bluee, alphae;
-   png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
-} image_pixel;
-
-/* Shared utility function, see below. */
-static void
-image_pixel_setf(image_pixel *this, unsigned int max)
-{
-   this->redf = this->red / (double)max;
-   this->greenf = this->green / (double)max;
-   this->bluef = this->blue / (double)max;
-   this->alphaf = this->alpha / (double)max;
-
-   if (this->red < max)
-      this->rede = this->redf * DBL_EPSILON;
-   else
-      this->rede = 0;
-   if (this->green < max)
-      this->greene = this->greenf * DBL_EPSILON;
-   else
-      this->greene = 0;
-   if (this->blue < max)
-      this->bluee = this->bluef * DBL_EPSILON;
-   else
-      this->bluee = 0;
-   if (this->alpha < max)
-      this->alphae = this->alphaf * DBL_EPSILON;
-   else
-      this->alphae = 0;
-}
-
-/* Initialize the structure for the next pixel - call this before doing any
- * transforms and call it for each pixel since all the fields may need to be
- * reset.
- */
-static void
-image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
-    png_byte bit_depth, png_uint_32 x, standard_palette palette)
-{
-   PNG_CONST png_byte sample_depth = (png_byte)(colour_type ==
-      PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
-   PNG_CONST unsigned int max = (1U<<sample_depth)-1;
-
-   /* Initially just set everything to the same number and the alpha to opaque.
-    * Note that this currently assumes a simple palette where entry x has colour
-    * rgb(x,x,x)!
-    */
-   this->palette_index = this->red = this->green = this->blue =
-      sample(row, colour_type, bit_depth, x, 0);
-   this->alpha = max;
-   this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
-      sample_depth;
-
-   /* Then override as appropriate: */
-   if (colour_type == 3) /* palette */
-   {
-      /* This permits the caller to default to the sample value. */
-      if (palette != 0)
-      {
-         PNG_CONST unsigned int i = this->palette_index;
-
-         this->red = palette[i].red;
-         this->green = palette[i].green;
-         this->blue = palette[i].blue;
-         this->alpha = palette[i].alpha;
-      }
-   }
-
-   else /* not palette */
-   {
-      unsigned int i = 0;
-
-      if (colour_type & 2)
-      {
-         this->green = sample(row, colour_type, bit_depth, x, 1);
-         this->blue = sample(row, colour_type, bit_depth, x, 2);
-         i = 2;
-      }
-      if (colour_type & 4)
-         this->alpha = sample(row, colour_type, bit_depth, x, ++i);
-   }
-
-   /* Calculate the scaled values, these are simply the values divided by
-    * 'max' and the error is initialized to the double precision epsilon value
-    * from the header file.
-    */
-   image_pixel_setf(this, max);
-
-   /* Store the input information for use in the transforms - these will
-    * modify the information.
-    */
-   this->colour_type = colour_type;
-   this->bit_depth = bit_depth;
-   this->sample_depth = sample_depth;
-   this->have_tRNS = 0;
-}
-
-/* Convert a palette image to an rgb image.  This necessarily converts the tRNS
- * chunk at the same time, because the tRNS will be in palette form.
- */
-static void
-image_pixel_convert_PLTE(image_pixel *this, const standard_display *display)
-{
-   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      PNG_CONST unsigned int i = this->palette_index;
-
-      this->bit_depth = this->sample_depth;
-      this->red = display->palette[i].red;
-      this->green = display->palette[i].green;
-      this->blue = display->palette[i].blue;
-      this->red_sBIT = display->red_sBIT;
-      this->green_sBIT = display->green_sBIT;
-      this->blue_sBIT = display->blue_sBIT;
-
-      if (this->have_tRNS)
-      {
-         this->alpha = display->palette[i].alpha;
-         this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
-         this->have_tRNS = 0;
-      }
-      else
-      {
-         this->alpha = 255;
-         this->colour_type = PNG_COLOR_TYPE_RGB;
-      }
-      this->alpha_sBIT = 8;
-
-      /* And regenerate the scaled values and all the errors, which are now set
-       * back to the initial values.
-       */
-      image_pixel_setf(this, 255);
-   }
-}
-
-/* Add an alpha channel, this will glom in the tRNS information because tRNS is
- * not valid in an alpha image.  The bit depth will invariably be set to at
- * least 8.  Palette images will be converted to alpha (using the above API).
- */
-static void
-image_pixel_add_alpha(image_pixel *this, const standard_display *display)
-{
-   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
-      image_pixel_convert_PLTE(this, display);
-
-   if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
-   {
-      if (this->colour_type == PNG_COLOR_TYPE_GRAY)
-      {
-         if (this->bit_depth < 8)
-            this->bit_depth = 8;
-
-         if (this->have_tRNS)
-         {
-            this->have_tRNS = 0;
-
-            /* Check the input, original, channel value here against the
-             * original tRNS gray chunk valie.
-             */
-            if (this->red == display->transparent.red)
-               this->alphaf = 0;
-            else
-               this->alphaf = 1;
-         }
-         else
-            this->alphaf = 1;
-
-         this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
-      }
-
-      else if (this->colour_type == PNG_COLOR_TYPE_RGB)
-      {
-         if (this->have_tRNS)
-         {
-            this->have_tRNS = 0;
-
-            /* Again, check the exact input values, not the current transformed
-             * value!
-             */
-            if (this->red == display->transparent.red &&
-               this->green == display->transparent.green &&
-               this->blue == display->transparent.blue)
-               this->alphaf = 0;
-            else
-               this->alphaf = 1;
-
-            this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
-         }
-      }
-
-      /* The error in the alpha is zero and the sBIT value comes from the
-       * original sBIT data (actually it will always be the original bit depth).
-       */
-      this->alphae = 0;
-      this->alpha_sBIT = display->alpha_sBIT;
-   }
-}
-
-struct transform_display;
-typedef struct image_transform
-{
-   /* The name of this transform: a string. */
-   PNG_CONST char *name;
-
-   /* Each transform can be disabled from the command line: */
-   int enable;
-
-   /* The global list of transforms; read only. */
-   struct image_transform *PNG_CONST list;
-
-   /* The global count of the number of times this transform has been set on an
-    * image.
-    */
-   unsigned int global_use;
-
-   /* The local count of the number of times this transform has been set. */
-   unsigned int local_use;
-
-   /* The next transform in the list, each transform must call its own next
-    * transform after it has processed the pixel successfully.
-    */
-   PNG_CONST struct image_transform *next;
-
-   /* A single transform for the image, expressed as a series of function
-    * callbacks and some space for values.
-    *
-    * First a callback to set the transform on the current png_read_struct:
-    */
-   void (*set)(PNG_CONST struct image_transform *this,
-      struct transform_display *that, png_structp pp, png_infop pi);
-
-   /* Then a transform that takes an input pixel in one PNG format or another
-    * and modifies it by a pngvalid implementation of the transform (thus
-    * duplicating the libpng intent without, we hope, duplicating the bugs
-    * in the libpng implementation!)  The png_structp is solely to allow error
-    * reporting via png_error and png_warning.
-    */
-   void (*mod)(PNG_CONST struct image_transform *this, image_pixel *that,
-      png_structp pp, PNG_CONST struct transform_display *display);
-
-   /* Add this transform to the list and return true if the transform is
-    * meaningful for this colour type and bit depth - if false then the
-    * transform should have no effect on the image so there's not a lot of
-    * point running it.
-    */
-   int (*add)(struct image_transform *this,
-      PNG_CONST struct image_transform **that, png_byte colour_type,
-      png_byte bit_depth);
-} image_transform;
-
-typedef struct transform_display
-{
-   standard_display this;
-
-   /* Parameters */
-   png_modifier*              pm;
-   PNG_CONST image_transform* transform_list;
-
-   /* Local variables */
-   png_byte output_colour_type;
-   png_byte output_bit_depth;
-} transform_display;
-
-/* Two functions to end the list: */
-static void
-image_transform_set_end(PNG_CONST image_transform *this,
-   transform_display *that, png_structp pp, png_infop pi)
-{
-   UNUSED(this)
-   UNUSED(that)
-   UNUSED(pp)
-   UNUSED(pi)
-}
-
-/* At the end of the list recalculate the output image pixel value from the
- * double precision values set up by the preceding 'mod' calls:
- */
-static unsigned int
-sample_scale(double sample_value, unsigned int scale)
-{
-   sample_value = floor(sample_value * scale + .5);
-
-   /* Return NaN as 0: */
-   if (!(sample_value > 0))
-      sample_value = 0;
-   else if (sample_value > scale)
-      sample_value = scale;
-
-   return (unsigned int)sample_value;
-}
-
-static void
-image_transform_mod_end(PNG_CONST image_transform *this, image_pixel *that,
-    png_structp pp, PNG_CONST transform_display *display)
-{
-   PNG_CONST unsigned int scale = (1U<<that->sample_depth)-1;
-
-   UNUSED(this)
-   UNUSED(pp)
-   UNUSED(display)
-
-   /* At the end recalculate the digitized red green and blue values according
-    * to the current sample_depth of the pixel.
-    *
-    * The sample value is simply scaled to the maximum, checking for over
-    * and underflow (which can both happen for some image transforms,
-    * including simple size scaling, though libpng doesn't do that at present.
-    */
-   that->red = sample_scale(that->redf, scale);
-
-   /* The error value is increased, at the end, according to the lowest sBIT
-    * value seen.  Common sense tells us that the intermediate integer
-    * representations are no more accurate than +/- 0.5 in the integral values,
-    * the sBIT allows the implementation to be worse than this.  In addition the
-    * PNG specification actually permits any error within the range (-1..+1),
-    * but that is ignored here.  Instead the final digitized value is compared,
-    * below to the digitized value of the error limits - this has the net effect
-    * of allowing (almost) +/-1 in the output value.  It's difficult to see how
-    * any algorithm that digitizes intermediate results can be more accurate.
-    */
-   that->rede += 1./(2*((1U<<that->red_sBIT)-1));
-
-   if (that->colour_type & PNG_COLOR_MASK_COLOR)
-   {
-      that->green = sample_scale(that->greenf, scale);
-      that->blue = sample_scale(that->bluef, scale);
-      that->greene += 1./(2*((1U<<that->green_sBIT)-1));
-      that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
-   }
-   else
-   {
-      that->blue = that->green = that->red;
-      that->bluef = that->greenf = that->redf;
-      that->bluee = that->greene = that->rede;
-   }
-
-   if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
-      that->colour_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      that->alpha = sample_scale(that->alphaf, scale);
-      that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
-   }
-   else
-   {
-      that->alpha = scale; /* opaque */
-      that->alpha = 1;     /* Override this. */
-      that->alphae = 0;    /* It's exact ;-) */
-   }
-}
-
-/* Static 'end' structure: */
-static image_transform image_transform_end =
-{
-   "(end)", /* name */
-   1, /* enable */
-   0, /* list */
-   0, /* global_use */
-   0, /* local_use */
-   0, /* next */
-   image_transform_set_end,
-   image_transform_mod_end,
-   0 /* never called, I want it to crash if it is! */
-};
-
-/* Reader callbacks and implementations, where they differ from the standard
- * ones.
- */
-static void
-transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
-    PNG_CONST image_transform *transform_list)
-{
-   /* Standard fields */
-   standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/);
-
-   /* Parameter fields */
-   dp->pm = pm;
-   dp->transform_list = transform_list;
-
-   /* Local variable fields */
-   dp->output_colour_type = 255; /* invalid */
-   dp->output_bit_depth = 255;  /* invalid */
-}
-
-static void
-transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
-{
-   /* Reuse the standard stuff as appropriate. */
-   standard_info_part1(&dp->this, pp, pi);
-
-   /* Now set the list of transforms. */
-   dp->transform_list->set(dp->transform_list, dp, pp, pi);
-
-   /* Update the info structure for these transforms: */
-   png_read_update_info(pp, pi);
-
-   /* And get the output information into the standard_display */
-   standard_info_part2(&dp->this, pp, pi, 1/*images*/);
-
-   /* Plus the extra stuff we need for the transform tests: */
-   dp->output_colour_type = png_get_color_type(pp, pi);
-   dp->output_bit_depth = png_get_bit_depth(pp, pi);
-
-   /* Validate the combination of colour type and bit depth that we are getting
-    * out of libpng; the semantics of something not in the PNG spec are, at
-    * best, unclear.
-    */
-   switch (dp->output_colour_type)
-   {
-   case PNG_COLOR_TYPE_PALETTE:
-      if (dp->output_bit_depth > 8) goto error;
-      /*FALL THROUGH*/
-   case PNG_COLOR_TYPE_GRAY:
-      if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
-         dp->output_bit_depth == 4)
-         break;
-      /*FALL THROUGH*/
-   default:
-      if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
-         break;
-      /*FALL THROUGH*/
-   error:
-      {
-         char message[128];
-         size_t pos;
-
-         pos = safecat(message, sizeof message, 0,
-            "invalid final bit depth: colour type(");
-         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
-         pos = safecat(message, sizeof message, pos, ") with bit depth: ");
-         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
-
-         png_error(pp, message);
-      }
-   }
-
-   /* Use a test pixel to check that the output agrees with what we expect -
-    * this avoids running the whole test if the output is unexpected.
-    */
-   {
-      image_pixel test_pixel;
-
-      memset(&test_pixel, 0, sizeof test_pixel);
-      test_pixel.colour_type = dp->this.colour_type; /* input */
-      test_pixel.bit_depth = dp->this.bit_depth;
-      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
-         test_pixel.sample_depth = 8;
-      else
-         test_pixel.sample_depth = test_pixel.bit_depth;
-      /* Don't need sBIT here */
-      test_pixel.have_tRNS = dp->this.is_transparent;
-
-      dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
-
-      if (test_pixel.colour_type != dp->output_colour_type)
-      {
-         char message[128];
-         size_t pos = safecat(message, sizeof message, 0, "colour type ");
-
-         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
-         pos = safecat(message, sizeof message, pos, " expected ");
-         pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
-
-         png_error(pp, message);
-      }
-
-      if (test_pixel.bit_depth != dp->output_bit_depth)
-      {
-         char message[128];
-         size_t pos = safecat(message, sizeof message, 0, "bit depth ");
-
-         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
-         pos = safecat(message, sizeof message, pos, " expected ");
-         pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
-
-         png_error(pp, message);
-      }
-
-      /* If both bit depth and colour type are correct check the sample depth.
-       * I believe these are both internal errors.
-       */
-      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         if (test_pixel.sample_depth != 8) /* oops - internal error! */
-            png_error(pp, "pngvalid: internal: palette sample depth not 8");
-      }
-      else if (test_pixel.sample_depth != dp->output_bit_depth)
-      {
-         char message[128];
-         size_t pos = safecat(message, sizeof message, 0,
-            "internal: sample depth ");
-
-         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
-         pos = safecat(message, sizeof message, pos, " expected ");
-         pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
-
-         png_error(pp, message);
-      }
-   }
-}
-
-static void
-transform_info(png_structp pp, png_infop pi)
-{
-   transform_info_imp(png_get_progressive_ptr(pp), pp, pi);
-}
-
-static void
-transform_range_check(png_structp pp, unsigned int r, unsigned int g,
-   unsigned int b, unsigned int a, unsigned int in_digitized, double in,
-   unsigned int out, png_byte sample_depth, double err, PNG_CONST char *name)
-{
-   /* Compare the scaled, digitzed, values of our local calculation (in+-err)
-    * with the digitized values libpng produced;  'sample_depth' is the actual
-    * digitization depth of the libpng output colors (the bit depth except for
-    * palette images where it is always 8.)
-    */
-   unsigned int max = (1U<<sample_depth)-1;
-   double in_min = ceil((in-err)*max - .5);
-   double in_max = floor((in+err)*max + .5);
-   if (!(out >= in_min && out <= in_max))
-   {
-      char message[256];
-      size_t pos;
-
-      pos = safecat(message, sizeof message, 0, name);
-      pos = safecat(message, sizeof message, pos, " output value error: rgba(");
-      pos = safecatn(message, sizeof message, pos, r);
-      pos = safecat(message, sizeof message, pos, ",");
-      pos = safecatn(message, sizeof message, pos, g);
-      pos = safecat(message, sizeof message, pos, ",");
-      pos = safecatn(message, sizeof message, pos, b);
-      pos = safecat(message, sizeof message, pos, ",");
-      pos = safecatn(message, sizeof message, pos, a);
-      pos = safecat(message, sizeof message, pos, "): ");
-      pos = safecatn(message, sizeof message, pos, out);
-      pos = safecat(message, sizeof message, pos, " expected: ");
-      pos = safecatn(message, sizeof message, pos, in_digitized);
-      pos = safecat(message, sizeof message, pos, " (");
-      pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
-      pos = safecat(message, sizeof message, pos, "..");
-      pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
-      pos = safecat(message, sizeof message, pos, ")");
-
-      png_error(pp, message);
-   }
-}
-
-static void
-transform_image_validate(transform_display *dp, png_structp pp, png_infop pi,
-    png_const_bytep pRow)
-{
-   /* Constants for the loop below: */
-   PNG_CONST png_byte in_ct = dp->this.colour_type;
-   PNG_CONST png_byte in_bd = dp->this.bit_depth;
-   PNG_CONST png_uint_32 w = dp->this.w;
-   PNG_CONST png_uint_32 h = dp->this.h;
-   PNG_CONST size_t cbRow = dp->this.cbRow;
-   PNG_CONST png_byte out_ct = dp->output_colour_type;
-   PNG_CONST png_byte out_bd = dp->output_bit_depth;
-   PNG_CONST png_byte sample_depth = (png_byte)(out_ct ==
-      PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
-   PNG_CONST png_byte red_sBIT = dp->this.red_sBIT;
-   PNG_CONST png_byte green_sBIT = dp->this.green_sBIT;
-   PNG_CONST png_byte blue_sBIT = dp->this.blue_sBIT;
-   PNG_CONST png_byte alpha_sBIT = dp->this.alpha_sBIT;
-   PNG_CONST int have_tRNS = dp->this.is_transparent;
-
-   standard_palette out_palette;
-   png_uint_32 y;
-
-   UNUSED(pi)
-
-   /* Read the palette corresponding to the output if the output colour type
-    * indicates a palette, othewise set out_palette to garbage.
-    */
-   if (out_ct == PNG_COLOR_TYPE_PALETTE)
-      (void)standard_palette_init(out_palette, pp, pi);
-   else
-      memset(out_palette, 0x5e, sizeof out_palette);
-
-   for (y=0; y<h; ++y, pRow += cbRow)
-   {
-      png_uint_32 x;
-
-      /* The original, standard, row pre-transforms. */
-      png_byte std[STANDARD_ROWMAX];
-
-      transform_row(pp, std, in_ct, in_bd, y);
-
-      /* Go through each original pixel transforming it and comparing with what
-       * libpng did to the same pixel.
-       */
-      for (x=0; x<w; ++x)
-      {
-         image_pixel in_pixel, out_pixel;
-         unsigned int r, g, b, a;
-
-         /* Find out what we think the pixel should be: */
-         image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette);
-
-         in_pixel.red_sBIT = red_sBIT;
-         in_pixel.green_sBIT = green_sBIT;
-         in_pixel.blue_sBIT = blue_sBIT;
-         in_pixel.alpha_sBIT = alpha_sBIT;
-         in_pixel.have_tRNS = have_tRNS;
-
-         /* For error detection, below. */
-         r = in_pixel.red;
-         g = in_pixel.green;
-         b = in_pixel.blue;
-         a = in_pixel.alpha;
-
-         dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
-
-         /* Read the output pixel and compare it to what we got, we don't
-          * use the error field here, so no need to update sBIT.
-          */
-         image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette);
-
-         /* We don't expect changes to the index here even if the bit depth is
-          * changed.
-          */
-         if (in_ct == PNG_COLOR_TYPE_PALETTE &&
-            out_ct == PNG_COLOR_TYPE_PALETTE)
-         {
-            if (in_pixel.palette_index != out_pixel.palette_index)
-               png_error(pp, "unexpected transformed palette index");
-         }
-
-         /* Check the colours for palette images too - in fact the palette could
-          * be separately verified itself in most cases.
-          */
-         if (in_pixel.red != out_pixel.red)
-            transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
-               out_pixel.red, sample_depth, in_pixel.rede, "red/gray");
-
-         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
-            in_pixel.green != out_pixel.green)
-            transform_range_check(pp, r, g, b, a, in_pixel.green,
-               in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
-               "green");
-
-         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
-            in_pixel.blue != out_pixel.blue)
-            transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
-               out_pixel.blue, sample_depth, in_pixel.bluee, "blue");
-
-         if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
-            in_pixel.alpha != out_pixel.alpha)
-            transform_range_check(pp, r, g, b, a, in_pixel.alpha,
-               in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
-               "alpha");
-      } /* pixel (x) loop */
-   } /* row (y) loop */
-
-   /* Record that something was actually checked to avoid a false positive. */
-   dp->this.ps->validated = 1;
-}
-
-static void
-transform_end(png_structp pp, png_infop pi)
-{
-   transform_display *dp = png_get_progressive_ptr(pp);
-
-   transform_image_validate(dp, pp, pi, dp->this.ps->image);
-}
-
-/* A single test run. */
-static void
-transform_test(png_modifier *pmIn, PNG_CONST png_uint_32 idIn,
-    PNG_CONST image_transform* transform_listIn, PNG_CONST char *name)
-{
-   transform_display d;
-   context(&pmIn->this, fault);
-
-   transform_display_init(&d, pmIn, idIn, transform_listIn);
-
-   Try
-   {
-      png_structp pp;
-      png_infop pi;
-
-      /* Get a png_struct for writing the image. */
-      pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
-
-#     if 0
-         /* Logging (debugging only) */
-         {
-            char buffer[256];
-
-            (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
-               "running test");
-
-            fprintf(stderr, "%s\n", buffer);
-         }
-#     endif
-
-      /* Introduce the correct read function. */
-      if (d.pm->this.progressive)
-      {
-         /* Share the row function with the standard implementation. */
-         png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
-            transform_end);
-
-         /* Now feed data into the reader until we reach the end: */
-         modifier_progressive_read(d.pm, pp, pi);
-      }
-      else
-      {
-         /* modifier_read expects a png_modifier* */
-         png_set_read_fn(pp, d.pm, modifier_read);
-
-         /* Check the header values: */
-         png_read_info(pp, pi);
-
-         /* Process the 'info' requirements. Only one image is generated */
-         transform_info_imp(&d, pp, pi);
-
-         sequential_row(&d.this, pp, pi, NULL, d.this.ps->image);
-
-         transform_image_validate(&d, pp, pi, d.this.ps->image);
-      }
-
-      modifier_reset(d.pm);
-   }
-
-   Catch(fault)
-      modifier_reset((png_modifier*)fault);
-}
-
-/* The transforms: */
-#define ITSTRUCT(name) image_transform_##name
-#define IT(name,prev)\
-static image_transform ITSTRUCT(name) =\
-{\
-   #name,\
-   1, /*enable*/\
-   &ITSTRUCT(prev), /*list*/\
-   0, /*global_use*/\
-   0, /*local_use*/\
-   0, /*next*/\
-   image_transform_png_set_##name##_set,\
-   image_transform_png_set_##name##_mod,\
-   image_transform_png_set_##name##_add\
-}
-
-/* To save code: */
-static int
-image_transform_default_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(colour_type)
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return 1;
-}
-
-/* png_set_palette_to_rgb */
-static void
-image_transform_png_set_palette_to_rgb_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_palette_to_rgb(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_palette_to_rgb_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
-      image_pixel_convert_PLTE(that, &display->this);
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_palette_to_rgb_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return colour_type == PNG_COLOR_TYPE_PALETTE;
-}
-
-IT(palette_to_rgb, end);
-
-
-/* png_set_tRNS_to_alpha */
-static void
-image_transform_png_set_tRNS_to_alpha_set(PNG_CONST image_transform *this,
-   transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_tRNS_to_alpha(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_tRNS_to_alpha_mod(PNG_CONST image_transform *this,
-   image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   /* LIBPNG BUG: this always forces palette images to RGB. */
-   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
-      image_pixel_convert_PLTE(that, &display->this);
-
-   /* This effectively does an 'expand' only if there is some transparency to
-    * covert to an alpha channel.
-    */
-   if (that->have_tRNS)
-      image_pixel_add_alpha(that, &display->this);
-
-   /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
-   else
-   {
-      if (that->bit_depth < 8)
-         that->bit_depth =8;
-      if (that->sample_depth < 8)
-         that->sample_depth = 8;
-   }
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   /* We don't know yet whether there will be a tRNS chunk, but we know that
-    * this transformation should do nothing if there already is an alpha
-    * channel.
-    */
-   return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
-}
-
-IT(tRNS_to_alpha,palette_to_rgb);
-
-/* png_set_gray_to_rgb */
-static void
-image_transform_png_set_gray_to_rgb_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_gray_to_rgb(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_gray_to_rgb_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   /* NOTE: we can actually pend the tRNS processing at this point because we
-    * can correctly recognize the original pixel value even though we have
-    * mapped the one gray channel to the three RGB ones, but in fact libpng
-    * doesn't do this, so we don't either.
-    */
-   if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
-      image_pixel_add_alpha(that, &display->this);
-
-   /* Simply expand the bit depth and alter the colour type as required. */
-   if (that->colour_type == PNG_COLOR_TYPE_GRAY)
-   {
-      /* RGB images have a bit depth at least equal to '8' */
-      if (that->bit_depth < 8)
-         that->sample_depth = that->bit_depth = 8;
-
-      /* And just changing the colour type works here because the green and blue
-       * channels are being maintained in lock-step with the red/gray:
-       */
-      that->colour_type = PNG_COLOR_TYPE_RGB;
-   }
-
-   else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_gray_to_rgb_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
-}
-
-IT(gray_to_rgb,tRNS_to_alpha);
-
-/* png_set_expand */
-static void
-image_transform_png_set_expand_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_expand(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_expand_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   /* The general expand case depends on what the colour type is: */
-   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
-      image_pixel_convert_PLTE(that, &display->this);
-   else if (that->bit_depth < 8) /* grayscale */
-      that->sample_depth = that->bit_depth = 8;
-
-   if (that->have_tRNS)
-      image_pixel_add_alpha(that, &display->this);
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_expand_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
-    * depth is at least 8 already.
-    */
-   return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
-}
-
-IT(expand,gray_to_rgb);
-
-/* png_set_expand_gray_1_2_4_to_8
- * LIBPNG BUG: this just does an 'expand'
- */
-static void
-image_transform_png_set_expand_gray_1_2_4_to_8_set(
-    PNG_CONST image_transform *this, transform_display *that, png_structp pp,
-    png_infop pi)
-{
-   png_set_expand_gray_1_2_4_to_8(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_expand_gray_1_2_4_to_8_mod(
-    PNG_CONST image_transform *this, image_pixel *that, png_structp pp,
-    PNG_CONST transform_display *display)
-{
-   image_transform_png_set_expand_mod(this, that, pp, display);
-}
-
-static int
-image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   return image_transform_png_set_expand_add(this, that, colour_type,
-      bit_depth);
-}
-
-IT(expand_gray_1_2_4_to_8, expand);
-
-/* png_set_strip_16 */
-static void
-image_transform_png_set_strip_16_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_strip_16(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_strip_16_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   if (that->bit_depth == 16)
-   {
-      that->sample_depth = that->bit_depth = 8;
-      if (that->red_sBIT > 8) that->red_sBIT = 8;
-      if (that->green_sBIT > 8) that->green_sBIT = 8;
-      if (that->blue_sBIT > 8) that->blue_sBIT = 8;
-      if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
-
-#     ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
-         /* The strip 16 algoirithm drops the low 8 bits rather than calculating
-          * 1/257, so we need to adjust the permitted errors appropriately:
-          */
-         {
-            PNG_CONST double d = (255-128.5)/65535;
-            that->rede += d;
-            that->greene += d;
-            that->bluee += d;
-            that->alphae += d;
-         }
-#     endif
-   }
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_strip_16_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(colour_type)
-
-   this->next = *that;
-   *that = this;
-
-   return bit_depth > 8;
-}
-
-IT(strip_16, expand_gray_1_2_4_to_8);
-
-/* png_set_strip_alpha */
-static void
-image_transform_png_set_strip_alpha_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_strip_alpha(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_strip_alpha_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      that->colour_type = PNG_COLOR_TYPE_GRAY;
-   else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
-      that->colour_type = PNG_COLOR_TYPE_RGB;
-
-   that->have_tRNS = 0;
-   that->alphaf = 1;
-   that->alphae = 0;
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_strip_alpha_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
-}
-
-IT(strip_alpha,strip_16);
-
-/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
- * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
- *    png_fixed_point green)
- * png_get_rgb_to_gray_status
- *
- * At present the APIs are simply tested using the 16.16 fixed point conversion
- * values known to be used inside libpng:
- *
- *   red:    6968
- *   green: 23434
- *   blue:   2366
- *
- * NOTE: this currently ignores the gamma because no gamma is being set, the
- * tests on gamma need to happen in the gamma test set.
- */
-static void
-image_transform_png_set_rgb_to_gray_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   PNG_CONST int error_action = 1; /* no error, no defines in png.h */
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-      png_set_rgb_to_gray(pp, error_action, -1, -1);
-#  else
-      png_set_rgb_to_gray_fixed(pp, error_action, -1, -1);
-#  endif
-
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_rgb_to_gray_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
-   {
-      if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
-         image_pixel_convert_PLTE(that, &display->this);
-
-      /* Image now has RGB channels... */
-      that->bluef = that->greenf = that->redf = (that->redf * 6968 +
-         that->greenf * 23434 + that->bluef * 2366) / 32768;
-      that->bluee = that->greene = that->rede = (that->rede * 6968 +
-         that->greene * 23434 + that->bluee * 2366) / 32768 *
-         (1 + DBL_EPSILON * 6);
-
-      /* The sBIT is the minium of the three colour channel sBITs. */
-      if (that->red_sBIT > that->green_sBIT)
-         that->red_sBIT = that->green_sBIT;
-      if (that->red_sBIT > that->blue_sBIT)
-         that->red_sBIT = that->blue_sBIT;
-      that->blue_sBIT = that->green_sBIT = that->red_sBIT;
-
-      /* And zap the colour bit in the type: */
-      if (that->colour_type == PNG_COLOR_TYPE_RGB)
-         that->colour_type = PNG_COLOR_TYPE_GRAY;
-      else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
-         that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
-   }
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_rgb_to_gray_add(image_transform *this,
-    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
-   UNUSED(bit_depth)
-
-   this->next = *that;
-   *that = this;
-
-   return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
-}
-
-IT(rgb_to_gray,strip_alpha);
-
-/* png_set_background(png_structp, png_const_color_16p background_color,
- *    int background_gamma_code, int need_expand, double background_gamma)
- * png_set_background_fixed(png_structp, png_const_color_16p background_color,
- *    int background_gamma_code, int need_expand,
- *    png_fixed_point background_gamma)
- *
- * As with rgb_to_gray this ignores the gamma.
-*/
-static void
-image_transform_png_set_background_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_color_16 back;
-
-   /* Since we don't know the output bit depth at this point we must use the
-    * input values and ask libpng to expand the chunk as required.
-    */
-   back.index = 255; /* Should not be used */
-   back.gray = back.blue = back.green = back.red =
-      (png_uint_16)((1U << that->this.bit_depth) >> 1);
-
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-      png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, 1, 0);
-#  else
-      png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE, 1, 0);
-#  endif
-
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_background_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   /* Check for tRNS first: */
-   if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
-      image_pixel_add_alpha(that, &display->this);
-
-   /* This is only necessary if the alpha value is less than 1. */
-   if (that->alphaf < 1)
-   {
-      /* Repeat the calculation above and scale the result: */
-      unsigned int tmp = (1U << display->this.bit_depth);
-      double component = (tmp >> 1)/(double)(tmp-1);
-
-      /* Now we do the background calculation without any gamma correction. */
-      if (that->alphaf <= 0)
-      {
-         that->bluef = that->greenf = that->redf = component;
-         that->bluee = that->greene = that->rede = component * DBL_EPSILON;
-         that->blue_sBIT = that->green_sBIT = that->red_sBIT = that->bit_depth;
-      }
-
-      else
-      {
-         component *= 1-that->alphaf;
-         that->redf = that->redf * that->alphaf + component;
-         that->rede = that->rede * that->alphaf + that->redf * 3 * DBL_EPSILON;
-         that->greenf = that->greenf * that->alphaf + component;
-         that->greene = that->greene * that->alphaf + that->greenf * 3 *
-            DBL_EPSILON;
-         that->bluef = that->bluef * that->alphaf + component;
-         that->bluee = that->bluee * that->alphaf + that->bluef * 3 *
-            DBL_EPSILON;
-      }
-
-      /* Remove the alpha type and set the alpha. */
-      that->alphaf = 1;
-      that->alphae = 0;
-
-      if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
-         that->colour_type = PNG_COLOR_TYPE_RGB;
-      else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-         that->colour_type = PNG_COLOR_TYPE_GRAY;
-   }
-
-   this->next->mod(this->next, that, pp, display);
-}
-
-#define image_transform_png_set_background_add image_transform_default_add
-
-IT(background,rgb_to_gray);
-
-static image_transform *PNG_CONST image_transform_first = &ITSTRUCT(background);
-
-static void
-transform_enable(PNG_CONST char *name)
-{
-   /* Everything starts out enabled, so if we see an 'enable' disabled
-    * everything else the first time round.
-    */
-   static int all_disabled = 0;
-   int found_it = 0;
-   image_transform *list = image_transform_first;
-
-   while (list != &image_transform_end)
-   {
-      if (strcmp(list->name, name) == 0)
-      {
-         list->enable = 1;
-         found_it = 1;
-      }
-      else if (!all_disabled)
-         list->enable = 0;
-
-      list = list->list;
-   }
-
-   all_disabled = 1;
-
-   if (!found_it)
-   {
-      fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
-         name);
-      exit(1);
-   }
-}
-
-static void
-transform_disable(PNG_CONST char *name)
-{
-   image_transform *list = image_transform_first;
-
-   while (list != &image_transform_end)
-   {
-      if (strcmp(list->name, name) == 0)
-      {
-         list->enable = 0;
-         return;
-      }
-
-      list = list->list;
-   }
-
-   fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
-      name);
-   exit(1);
-}
-
-static void
-image_transform_reset_count(void)
-{
-   image_transform *next = image_transform_first;
-   int count = 0;
-
-   while (next != &image_transform_end)
-   {
-      next->local_use = 0;
-      next->next = 0;
-      next = next->list;
-      ++count;
-   }
-
-   /* This can only happen if we every have more than 32 transforms (excluding
-    * the end) in the list.
-    */
-   if (count > 32) abort();
-}
-
-static int
-image_transform_test_counter(png_uint_32 counter, unsigned int max)
-{
-   /* Test the list to see if there is any point contining, given a current
-    * counter and a 'max' value.
-    */
-   image_transform *next = image_transform_first;
-
-   while (next != &image_transform_end)
-   {
-      /* For max 0 or 1 continue until the counter overflows: */
-      counter >>= 1;
-
-      /* Continue if any entry hasn't reacked the max. */
-      if (max > 1 && next->local_use < max)
-         return 1;
-      next = next->list;
-   }
-
-   return max <= 1 && counter == 0;
-}
-
-static png_uint_32
-image_transform_add(PNG_CONST image_transform **this, unsigned int max,
-   png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
-   png_byte colour_type, png_byte bit_depth)
-{
-   for (;;) /* until we manage to add something */
-   {
-      png_uint_32 mask;
-      image_transform *list;
-
-      /* Find the next counter value, if the counter is zero this is the start
-       * of the list.  This routine always returns the current counter (not the
-       * next) so it returns 0 at the end and expects 0 at the beginning.
-       */
-      if (counter == 0) /* first time */
-      {
-         image_transform_reset_count();
-         if (max <= 1)
-            counter = 1;
-         else
-            counter = random_32();
-      }
-      else /* advance the counter */
-      {
-         switch (max)
-         {
-            case 0:  ++counter; break;
-            case 1:  counter <<= 1; break;
-            default: counter = random_32(); break;
-         }
-      }
-
-      /* Now add all these items, if possible */
-      *this = &image_transform_end;
-      list = image_transform_first;
-      mask = 1;
-
-      /* Go through the whole list adding anything that the counter selects: */
-      while (list != &image_transform_end)
-      {
-         if ((counter & mask) != 0 && list->enable &&
-             (max == 0 || list->local_use < max))
-         {
-            /* Candidate to add: */
-            if (list->add(list, this, colour_type, bit_depth) || max == 0)
-            {
-               /* Added, so add to the name too. */
-               *pos = safecat(name, sizeof_name, *pos, " +");
-               *pos = safecat(name, sizeof_name, *pos, list->name);
-            }
-
-            else
-            {
-               /* Not useful and max>0, so remvoe it from *this: */
-               *this = list->next;
-               list->next = 0;
-
-               /* And, since we know it isn't useful, stop it being added again
-                * in this run:
-                */
-               list->local_use = max;
-            }
-         }
-
-         mask <<= 1;
-         list = list->list;
-      }
-
-      /* Now if anything was added we have something to do. */
-      if (*this != &image_transform_end)
-         return counter;
-
-      /* Nothing added, but was there anything in there to add? */
-      if (!image_transform_test_counter(counter, max))
-         return 0;
-   }
-}
-
-#ifdef THIS_IS_THE_PROFORMA
-static void
-image_transform_png_set_@_set(PNG_CONST image_transform *this,
-    transform_display *that, png_structp pp, png_infop pi)
-{
-   png_set_@(pp);
-   this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_@_mod(PNG_CONST image_transform *this,
-    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
-   this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_@_add(image_transform *this,
-    PNG_CONST image_transform **that, char *name, size_t sizeof_name,
-    size_t *pos, png_byte colour_type, png_byte bit_depth)
-{
-   this->next = *that;
-   *that = this;
-
-   *pos = safecat(name, sizeof_name, *pos, " +@");
-
-   return 1;
-}
-
-IT(@);
-#endif
-
-/* png_set_quantize(png_structp, png_colorp palette, int num_palette,
- *    int maximum_colors, png_const_uint_16p histogram, int full_quantize)
- *
- * Very difficult to validate this!
- */
-/*NOTE: TBD NYI */
-
-/* The data layout transforms are handled by swapping our own channel data,
- * necessarily these need to happen at the end of the transform list because the
- * semantic of the channels changes after these are executed.  Some of these,
- * like set_shift and set_packing, can't be done at present because they change
- * the layout of the data at the sub-sample level so sample() won't get the
- * right answer.
- */
-/* png_set_invert_alpha */
-/*NOTE: TBD NYI */
-
-/* png_set_bgr */
-/*NOTE: TBD NYI */
-
-/* png_set_swap_alpha */
-/*NOTE: TBD NYI */
-
-/* png_set_swap */
-/*NOTE: TBD NYI */
-
-/* png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags)); */
-/*NOTE: TBD NYI */
-
-/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
-/*NOTE: TBD NYI */
-
-/* png_set_packing */
-/*NOTE: TBD NYI */
-
-/* png_set_packswap */
-/*NOTE: TBD NYI */
-
-/* png_set_invert_mono */
-/*NOTE: TBD NYI */
-
-/* png_set_shift(png_structp, png_const_color_8p true_bits) */
-/*NOTE: TBD NYI */
-
-static int
-test_transform(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
-    int bdlo, int PNG_CONST bdhi, png_uint_32 max)
-{
-   for (; bdlo <= bdhi; ++bdlo)
-   {
-      PNG_CONST png_byte bit_depth = DEPTH(bdlo);
-      png_uint_32 counter = 0;
-      size_t base_pos;
-      char name[64];
-
-      base_pos = safecat(name, sizeof name, 0, "transform:");
-
-      for (;;)
-      {
-         size_t pos = base_pos;
-         PNG_CONST image_transform *list = 0;
-
-         counter = image_transform_add(&list, max, counter, name, sizeof name,
-            &pos, colour_type, bit_depth);
-
-         if (counter == 0)
-            break;
-
-         /* The command line can change this to checking interlaced images. */
-         transform_test(pm, FILEID(colour_type, bit_depth, pm->interlace_type,
-            0, 0, 0), list, name);
-
-         if (fail(pm))
-            return 0;
-      }
-   }
-
-   return 1; /* keep going */
-}
-
-static void
-perform_transform_test(png_modifier *pm)
-{
-   /* Test each colour type over the valid range of bit depths (expressed as
-    * log2(bit_depth) in turn, stop as soon as any error is detected.
-    */
-   if (!test_transform(pm, 0, 0, READ_BDHI, 1))
-      return;
-
-   if (!test_transform(pm, 2, 3, READ_BDHI, 1))
-      return;
-
-   if (!test_transform(pm, 3, 0, 3, 1))
-      return;
-
-   if (!test_transform(pm, 4, 3, READ_BDHI, 1))
-      return;
-
-   if (!test_transform(pm, 6, 3, READ_BDHI, 1))
-      return;
-}
-
-
-/********************************* GAMMA TESTS ********************************/
-/* Gamma test images. */
-typedef struct gamma_modification
-{
-   png_modification this;
-   png_fixed_point  gamma;
-} gamma_modification;
-
-static int
-gamma_modify(png_modifier *pm, png_modification *me, int add)
-{
-   UNUSED(add)
-   /* This simply dumps the given gamma value into the buffer. */
-   png_save_uint_32(pm->buffer, 4);
-   png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
-   png_save_uint_32(pm->buffer+8, ((gamma_modification*)me)->gamma);
-   return 1;
-}
-
-static void
-gamma_modification_init(gamma_modification *me, png_modifier *pm, double gammad)
-{
-   double g;
-
-   modification_init(&me->this);
-   me->this.chunk = CHUNK_gAMA;
-   me->this.modify_fn = gamma_modify;
-   me->this.add = CHUNK_PLTE;
-   g = floor(gammad * 100000 + .5);
-   me->gamma = (png_fixed_point)g;
-   me->this.next = pm->modifications;
-   pm->modifications = &me->this;
-}
-
-typedef struct srgb_modification
-{
-   png_modification this;
-   png_byte         intent;
-} srgb_modification;
-
-static int
-srgb_modify(png_modifier *pm, png_modification *me, int add)
-{
-   UNUSED(add)
-   /* As above, ignore add and just make a new chunk */
-   png_save_uint_32(pm->buffer, 1);
-   png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
-   pm->buffer[8] = ((srgb_modification*)me)->intent;
-   return 1;
-}
-
-static void
-srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
-{
-   modification_init(&me->this);
-   me->this.chunk = CHUNK_sBIT;
-
-   if (intent <= 3) /* if valid, else *delete* sRGB chunks */
-   {
-      me->this.modify_fn = srgb_modify;
-      me->this.add = CHUNK_PLTE;
-      me->intent = intent;
-   }
-
-   else
-   {
-      me->this.modify_fn = 0;
-      me->this.add = 0;
-      me->intent = 0;
-   }
-
-   me->this.next = pm->modifications;
-   pm->modifications = &me->this;
-}
-
-typedef struct sbit_modification
-{
-   png_modification this;
-   png_byte         sbit;
-} sbit_modification;
-
-static int
-sbit_modify(png_modifier *pm, png_modification *me, int add)
-{
-   png_byte sbit = ((sbit_modification*)me)->sbit;
-   if (pm->bit_depth > sbit)
-   {
-      int cb = 0;
-      switch (pm->colour_type)
-      {
-         case 0:
-            cb = 1;
-            break;
-
-         case 2:
-         case 3:
-            cb = 3;
-            break;
-
-         case 4:
-            cb = 2;
-            break;
-
-         case 6:
-            cb = 4;
-            break;
-
-         default:
-            png_error(pm->this.pread,
-               "unexpected colour type in sBIT modification");
-      }
-
-      png_save_uint_32(pm->buffer, cb);
-      png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
-
-      while (cb > 0)
-         (pm->buffer+8)[--cb] = sbit;
-
-      return 1;
-   }
-   else if (!add)
-   {
-      /* Remove the sBIT chunk */
-      pm->buffer_count = pm->buffer_position = 0;
-      return 1;
-   }
-   else
-      return 0; /* do nothing */
-}
-
-static void
-sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
-{
-   modification_init(&me->this);
-   me->this.chunk = CHUNK_sBIT;
-   me->this.modify_fn = sbit_modify;
-   me->this.add = CHUNK_PLTE;
-   me->sbit = sbit;
-   me->this.next = pm->modifications;
-   pm->modifications = &me->this;
-}
-
-/* Reader callbacks and implementations, where they differ from the standard
- * ones.
- */
-typedef struct gamma_display
-{
-   standard_display this;
-
-   /* Parameters */
-   png_modifier*    pm;
-   double           file_gamma;
-   double           screen_gamma;
-   png_byte         sbit;
-   int              threshold_test;
-   PNG_CONST char*  name;
-   int              speed;
-   int              use_input_precision;
-   int              strip16;
-
-   /* Local variables */
-   double       maxerrout;
-   double       maxerrpc;
-   double       maxerrabs;
-} gamma_display;
-
-static void
-gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
-    double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
-    int speed, int use_input_precision, int strip16)
-{
-   /* Standard fields */
-   standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/);
-
-   /* Parameter fields */
-   dp->pm = pm;
-   dp->file_gamma = file_gamma;
-   dp->screen_gamma = screen_gamma;
-   dp->sbit = sbit;
-   dp->threshold_test = threshold_test;
-   dp->speed = speed;
-   dp->use_input_precision = use_input_precision;
-   dp->strip16 = strip16;
-
-   /* Local variable fields */
-   dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
-}
-
-static void
-gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
-{
-   /* Reuse the standard stuff as appropriate. */
-   standard_info_part1(&dp->this, pp, pi);
-
-   /* If requested strip 16 to 8 bits - this is handled automagically below
-    * because the output bit depth is read from the library.  Note that there
-    * are interactions with sBIT but, internally, libpng makes sbit at most
-    * PNG_MAX_GAMMA_8 when doing the following.
-    */
-   if (dp->strip16)
-#     ifdef PNG_READ_16_TO_8_SUPPORTED
-         png_set_strip_16(pp);
-#     else
-         png_error(pp, "strip16 (16 to 8 bit conversion) not supported");
-#     endif
-
-   png_read_update_info(pp, pi);
-
-   /* Now we may get a different cbRow: */
-   standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
-}
-
-static void
-gamma_info(png_structp pp, png_infop pi)
-{
-   gamma_info_imp(png_get_progressive_ptr(pp), pp, pi);
-}
-
-static void
-gamma_image_validate(gamma_display *dp, png_structp pp, png_infop pi,
-    png_const_bytep pRow)
-{
-   /* Get some constants derived from the input and output file formats: */
-   PNG_CONST png_byte sbit = dp->sbit;
-   PNG_CONST double file_gamma = dp->file_gamma;
-   PNG_CONST double screen_gamma = dp->screen_gamma;
-   PNG_CONST int use_input_precision = dp->use_input_precision;
-   PNG_CONST int speed = dp->speed;
-   PNG_CONST png_byte in_ct = dp->this.colour_type;
-   PNG_CONST png_byte in_bd = dp->this.bit_depth;
-   PNG_CONST png_uint_32 w = dp->this.w;
-   PNG_CONST png_uint_32 h = dp->this.h;
-   PNG_CONST size_t cbRow = dp->this.cbRow;
-   PNG_CONST png_byte out_ct = png_get_color_type(pp, pi);
-   PNG_CONST png_byte out_bd = png_get_bit_depth(pp, pi);
-   PNG_CONST unsigned int outmax = (1U<<out_bd)-1;
-   PNG_CONST double maxabs = abserr(dp->pm, out_bd);
-   PNG_CONST double maxout = outerr(dp->pm, out_bd);
-   PNG_CONST double maxpc = pcerr(dp->pm, out_bd);
-
-   /* There are three sources of error, firstly the quantization in the
-    * file encoding, determined by sbit and/or the file depth, secondly
-    * the output (screen) gamma and thirdly the output file encoding.
-    *
-    * Since this API receives the screen and file gamma in double
-    * precision it is possible to calculate an exact answer given an input
-    * pixel value.  Therefore we assume that the *input* value is exact -
-    * sample/maxsample - calculate the corresponding gamma corrected
-    * output to the limits of double precision arithmetic and compare with
-    * what libpng returns.
-    *
-    * Since the library must quantize the output to 8 or 16 bits there is
-    * a fundamental limit on the accuracy of the output of +/-.5 - this
-    * quantization limit is included in addition to the other limits
-    * specified by the paramaters to the API.  (Effectively, add .5
-    * everywhere.)
-    *
-    * The behavior of the 'sbit' paramter is defined by section 12.5
-    * (sample depth scaling) of the PNG spec.  That section forces the
-    * decoder to assume that the PNG values have been scaled if sBIT is
-    * present:
-    *
-    *     png-sample = floor( input-sample * (max-out/max-in) + .5);
-    *
-    * This means that only a subset of the possible PNG values should
-    * appear in the input. However, the spec allows the encoder to use a
-    * variety of approximations to the above and doesn't require any
-    * restriction of the values produced.
-    *
-    * Nevertheless the spec requires that the upper 'sBIT' bits of the
-    * value stored in a PNG file be the original sample bits.
-    * Consequently the code below simply scales the top sbit bits by
-    * (1<<sbit)-1 to obtain an original sample value.
-    *
-    * Because there is limited precision in the input it is arguable that
-    * an acceptable result is any valid result from input-.5 to input+.5.
-    * The basic tests below do not do this, however if
-    * 'use_input_precision' is set a subsequent test is performed below.
-    */
-   PNG_CONST int processing = (fabs(screen_gamma*file_gamma-1) >=
-      PNG_GAMMA_THRESHOLD && !dp->threshold_test && !speed && in_ct != 3) ||
-      in_bd != out_bd;
-
-   PNG_CONST unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
-
-   PNG_CONST double gamma_correction = 1/(file_gamma*screen_gamma);/* Overall */
-
-   double maxerrout = 0, maxerrabs = 0, maxerrpc = 0;
-   png_uint_32 y;
-
-   for (y=0; y<h; ++y, pRow += cbRow)
-   {
-      unsigned int s, x;
-      png_byte std[STANDARD_ROWMAX];
-
-      transform_row(pp, std, in_ct, in_bd, y);
-
-      if (processing)
-      {
-         for (x=0; x<w; ++x) for (s=0; s<samples_per_pixel; ++s)
-         {
-            /* Input sample values: */
-            PNG_CONST unsigned int
-               id = sample(std, in_ct, in_bd, x, s);
-
-            PNG_CONST unsigned int
-               od = sample(pRow, out_ct, out_bd, x, s);
-
-            PNG_CONST unsigned int
-               isbit = id >> (in_bd-sbit);
-
-            double i, input_sample, encoded_sample, output;
-            double encoded_error, error;
-            double es_lo, es_hi;
-
-            /* First check on the 'perfect' result obtained from the
-             * digitized input value, id, and compare this against the
-             * actual digitized result, 'od'.  'i' is the input result
-             * in the range 0..1:
-             *
-             * NOTE: sBIT should be taken into account here but isn't,
-             * as described above.
-             */
-            i = isbit; i /= (1U<<sbit)-1;
-
-            /* Then get the gamma corrected version of 'i' and compare
-             * to 'od', any error less than .5 is insignificant - just
-             * quantization of the output value to the nearest digital
-             * value (nevertheless the error is still recorded - it's
-             * interesting ;-)
-             */
-            encoded_sample = pow(i, gamma_correction) * outmax;
-            encoded_error = fabs(od-encoded_sample);
-
-            if (encoded_error > maxerrout)
-               maxerrout = encoded_error;
-
-            if (encoded_error < .5+maxout)
-               continue;
-
-            /* There may be an error, so calculate the actual sample
-             * values - unencoded light intensity values.  Note that
-             * in practice these are not unencoded because they
-             * include a 'viewing correction' to decrease or
-             * (normally) increase the perceptual contrast of the
-             * image.  There's nothing we can do about this - we don't
-             * know what it is - so assume the unencoded value is
-             * perceptually linear.
-             */
-            input_sample = pow(i, 1/file_gamma); /* In range 0..1 */
-            output = od;
-            output /= outmax;
-            output = pow(output, screen_gamma);
-
-            /* Now we have the numbers for real errors, both absolute
-             * values as as a percentage of the correct value (output):
-             */
-            error = fabs(input_sample-output);
-
-            if (error > maxerrabs)
-               maxerrabs = error;
-
-            /* The following is an attempt to ignore the tendency of
-             * quantization to dominate the percentage errors for low
-             * output sample values:
-             */
-            if (input_sample*maxpc > .5+maxabs)
-            {
-               double percentage_error = error/input_sample;
-               if (percentage_error > maxerrpc) maxerrpc = percentage_error;
-            }
-
-            /* Now calculate the digitization limits for
-             * 'encoded_sample' using the 'max' values.  Note that
-             * maxout is in the encoded space but maxpc and maxabs are
-             * in linear light space.
-             *
-             * First find the maximum error in linear light space,
-             * range 0..1:
-             */
-            {
-               double tmp = input_sample * maxpc;
-               if (tmp < maxabs) tmp = maxabs;
-
-               /* Low bound - the minimum of the three: */
-               es_lo = encoded_sample - maxout;
-
-               if (es_lo > 0 && input_sample-tmp > 0)
-               {
-                  double low_value = outmax * pow(input_sample-tmp,
-                     1/screen_gamma);
-                  if (low_value < es_lo) es_lo = low_value;
-               }
-
-               else
-                  es_lo = 0;
-
-               es_hi = encoded_sample + maxout;
-
-               if (es_hi < outmax && input_sample+tmp < 1)
-               {
-                  double high_value = outmax * pow(input_sample+tmp,
-                     1/screen_gamma);
-                  if (high_value > es_hi) es_hi = high_value;
-               }
-
-               else
-                  es_hi = outmax;
-            }
-
-            /* The primary test is that the final encoded value
-             * returned by the library should be between the two limits
-             * (inclusive) that were calculated above.  At this point
-             * quantization of the output must be taken into account.
-             */
-            if (od+.5 < es_lo || od-.5 > es_hi)
-            {
-               /* There has been an error in processing. */
-               double is_lo, is_hi;
-
-               if (use_input_precision)
-               {
-                  /* Ok, something is wrong - this actually happens in
-                   * current libpng sbit processing.  Assume that the
-                   * input value (id, adjusted for sbit) can be
-                   * anywhere between value-.5 and value+.5 - quite a
-                   * large range if sbit is low.
-                   */
-                  double tmp = (isbit - .5)/((1U<<sbit)-1);
-
-                  if (tmp > 0)
-                  {
-                     is_lo = outmax * pow(tmp, gamma_correction) - maxout;
-                     if (is_lo < 0) is_lo = 0;
-                  }
-
-                  else
-                     is_lo = 0;
-
-                  tmp = (isbit + .5)/((1U<<sbit)-1);
-
-                  if (tmp < 1)
-                  {
-                     is_hi = outmax * pow(tmp, gamma_correction) + maxout;
-                     if (is_hi > outmax) is_hi = outmax;
-                  }
-
-                  else
-                     is_hi = outmax;
-
-                  if (!(od+.5 < is_lo || od-.5 > is_hi))
-                     continue;
-               }
-               else
-                  is_lo = es_lo, is_hi = es_hi;
-
-               {
-                  char msg[256];
-
-                  sprintf(msg,
-                   "error: %.3f; %u{%u;%u} -> %u not %.2f (%.1f-%.1f)",
-                     od-encoded_sample, id, sbit, isbit, od,
-                     encoded_sample, is_lo, is_hi);
-
-                  png_warning(pp, msg);
-               }
-            }
-         }
-      }
-
-      else if (!speed && memcmp(std, pRow, cbRow) != 0)
-      {
-         char msg[64];
-
-         /* No transform is expected on the threshold tests. */
-         sprintf(msg, "gamma: below threshold row %d changed", y);
-
-         png_error(pp, msg);
-      }
-   } /* row (y) loop */
-
-   dp->maxerrout = maxerrout;
-   dp->maxerrabs = maxerrabs;
-   dp->maxerrpc = maxerrpc;
-   dp->this.ps->validated = 1;
-}
-
-static void
-gamma_end(png_structp pp, png_infop pi)
-{
-   gamma_display *dp = png_get_progressive_ptr(pp);
-
-   gamma_image_validate(dp, pp, pi, dp->this.ps->image);
-}
-
-/* A single test run checking a gamma transformation.
- *
- * maxabs: maximum absolute error as a fraction
- * maxout: maximum output error in the output units
- * maxpc:  maximum percentage error (as a percentage)
- */
-static void
-gamma_test(png_modifier *pmIn, PNG_CONST png_byte colour_typeIn,
-    PNG_CONST png_byte bit_depthIn, PNG_CONST int interlace_typeIn,
-    PNG_CONST double file_gammaIn, PNG_CONST double screen_gammaIn,
-    PNG_CONST png_byte sbitIn, PNG_CONST int threshold_testIn,
-    PNG_CONST char *name, PNG_CONST int speedIn,
-    PNG_CONST int use_input_precisionIn, PNG_CONST int strip16In)
-{
-   gamma_display d;
-   context(&pmIn->this, fault);
-
-   gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
-      interlace_typeIn, 0, 0, 0), file_gammaIn, screen_gammaIn, sbitIn,
-      threshold_testIn, speedIn, use_input_precisionIn, strip16In);
-
-   Try
-   {
-      png_structp pp;
-      png_infop pi;
-      gamma_modification gamma_mod;
-      srgb_modification srgb_mod;
-      sbit_modification sbit_mod;
-
-      /* Make an appropriate modifier to set the PNG file gamma to the
-       * given gamma value and the sBIT chunk to the given precision.
-       */
-      d.pm->modifications = NULL;
-      gamma_modification_init(&gamma_mod, d.pm, d.file_gamma);
-      srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
-      sbit_modification_init(&sbit_mod, d.pm, d.sbit);
-
-      modification_reset(d.pm->modifications);
-
-      /* Get a png_struct for writing the image. */
-      pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
-
-      /* Set up gamma processing. */
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-      png_set_gamma(pp, d.screen_gamma, d.file_gamma);
-#else
-      {
-         png_fixed_point s = floor(d.screen_gamma*100000+.5);
-         png_fixed_point f = floor(d.file_gamma*100000+.5);
-         png_set_gamma_fixed(pp, s, f);
-      }
-#endif
-
-      /* Introduce the correct read function. */
-      if (d.pm->this.progressive)
-      {
-         /* Share the row function with the standard implementation. */
-         png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
-            gamma_end);
-
-         /* Now feed data into the reader until we reach the end: */
-         modifier_progressive_read(d.pm, pp, pi);
-      }
-      else
-      {
-         /* modifier_read expects a png_modifier* */
-         png_set_read_fn(pp, d.pm, modifier_read);
-
-         /* Check the header values: */
-         png_read_info(pp, pi);
-
-         /* Process the 'info' requirements. Only one image is generated */
-         gamma_info_imp(&d, pp, pi);
-
-         sequential_row(&d.this, pp, pi, NULL, d.this.ps->image);
-
-         gamma_image_validate(&d, pp, pi, d.this.ps->image);
-      }
-
-      modifier_reset(d.pm);
-
-      if (d.pm->log && !d.threshold_test && !d.speed)
-         fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
-            d.this.bit_depth, colour_types[d.this.colour_type], d.name,
-            d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
-
-      /* Log the summary values too. */
-      if (d.this.colour_type == 0 || d.this.colour_type == 4)
-      {
-         switch (d.this.bit_depth)
-         {
-         case 1:
-            break;
-
-         case 2:
-            if (d.maxerrout > d.pm->error_gray_2)
-               d.pm->error_gray_2 = d.maxerrout;
-
-            break;
-
-         case 4:
-            if (d.maxerrout > d.pm->error_gray_4)
-               d.pm->error_gray_4 = d.maxerrout;
-
-            break;
-
-         case 8:
-            if (d.maxerrout > d.pm->error_gray_8)
-               d.pm->error_gray_8 = d.maxerrout;
-
-            break;
-
-         case 16:
-            if (d.maxerrout > d.pm->error_gray_16)
-               d.pm->error_gray_16 = d.maxerrout;
-
-            break;
-
-         default:
-            png_error(pp, "bad bit depth (internal: 1)");
-         }
-      }
-
-      else if (d.this.colour_type == 2 || d.this.colour_type == 6)
-      {
-         switch (d.this.bit_depth)
-         {
-         case 8:
-
-            if (d.maxerrout > d.pm->error_color_8)
-               d.pm->error_color_8 = d.maxerrout;
-
-            break;
-
-         case 16:
-
-            if (d.maxerrout > d.pm->error_color_16)
-               d.pm->error_color_16 = d.maxerrout;
-
-            break;
-
-         default:
-            png_error(pp, "bad bit depth (internal: 2)");
-         }
-      }
-   }
-
-   Catch(fault)
-      modifier_reset((png_modifier*)fault);
-}
-
-static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
-    png_byte bit_depth, int interlace_type, double file_gamma,
-    double screen_gamma)
-{
-   size_t pos = 0;
-   char name[64];
-   pos = safecat(name, sizeof name, pos, "threshold ");
-   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
-   pos = safecat(name, sizeof name, pos, "/");
-   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
-
-   (void)gamma_test(pm, colour_type, bit_depth, interlace_type, file_gamma,
-      screen_gamma, bit_depth, 1, name, 0 /*speed*/, 0 /*no input precision*/,
-      0 /*no strip16*/);
-}
-
-static void
-perform_gamma_threshold_tests(png_modifier *pm)
-{
-   png_byte colour_type = 0;
-   png_byte bit_depth = 0;
-
-   while (next_format(&colour_type, &bit_depth))
-   {
-      double test_gamma = 1.0;
-      while (test_gamma >= .4)
-      {
-         /* There's little point testing the interlacing vs non-interlacing,
-          * but this can be set from the command line.
-          */
-         gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
-            test_gamma, 1/test_gamma);
-         test_gamma *= .95;
-      }
-
-      /* And a special test for sRGB */
-      gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
-          .45455, 2.2);
-
-      if (fail(pm))
-         return;
-   }
-}
-
-static void gamma_transform_test(png_modifier *pm,
-   PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
-   PNG_CONST int interlace_type, PNG_CONST double file_gamma,
-   PNG_CONST double screen_gamma, PNG_CONST png_byte sbit, PNG_CONST int speed,
-   PNG_CONST int use_input_precision, PNG_CONST int strip16)
-{
-   size_t pos = 0;
-   char name[64];
-
-   if (sbit != bit_depth)
-   {
-      pos = safecat(name, sizeof name, pos, "sbit(");
-      pos = safecatn(name, sizeof name, pos, sbit);
-      pos = safecat(name, sizeof name, pos, ") ");
-   }
-
-   else
-      pos = safecat(name, sizeof name, pos, "gamma ");
-
-   if (strip16)
-      pos = safecat(name, sizeof name, pos, "16to8 ");
-
-   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
-   pos = safecat(name, sizeof name, pos, "->");
-   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
-
-   gamma_test(pm, colour_type, bit_depth, interlace_type, file_gamma,
-      screen_gamma, sbit, 0, name, speed, use_input_precision, strip16);
-}
-
-static void perform_gamma_transform_tests(png_modifier *pm, int speed)
-{
-   png_byte colour_type = 0;
-   png_byte bit_depth = 0;
-
-   /* Ignore palette images - the gamma correction happens on the palette entry,
-    * haven't got the tests for this yet.
-    */
-   while (next_format(&colour_type, &bit_depth)) if (colour_type != 3)
-   {
-      unsigned int i, j;
-
-      for (i=0; i<pm->ngammas; ++i) for (j=0; j<pm->ngammas; ++j) if (i != j)
-      {
-         gamma_transform_test(pm, colour_type, bit_depth, pm->interlace_type,
-            1/pm->gammas[i], pm->gammas[j], bit_depth, speed,
-            pm->use_input_precision, 0 /*do not strip16*/);
-
-         if (fail(pm))
-            return;
-      }
-   }
-}
-
-static void perform_gamma_sbit_tests(png_modifier *pm, int speed)
-{
-   png_byte sbit;
-
-   /* The only interesting cases are colour and grayscale, alpha is ignored here
-    * for overall speed.  Only bit depths 8 and 16 are tested.
-    */
-   for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
-   {
-      unsigned int i, j;
-
-      for (i=0; i<pm->ngammas; ++i)
-      {
-         for (j=0; j<pm->ngammas; ++j)
-         {
-            if (i != j)
-            {
-               if (sbit < 8)
-               {
-                  gamma_transform_test(pm, 0, 8, pm->interlace_type,
-                      1/pm->gammas[i], pm->gammas[j], sbit, speed,
-                      pm->use_input_precision_sbit, 0 /*strip16*/);
-
-                  if (fail(pm))
-                     return;
-
-                  gamma_transform_test(pm, 2, 8, pm->interlace_type,
-                      1/pm->gammas[i], pm->gammas[j], sbit, speed,
-                      pm->use_input_precision_sbit, 0 /*strip16*/);
-
-                  if (fail(pm))
-                     return;
-               }
-
-#ifdef DO_16BIT
-               gamma_transform_test(pm, 0, 16, pm->interlace_type,
-                   1/pm->gammas[i], pm->gammas[j], sbit, speed,
-                   pm->use_input_precision_sbit, 0 /*strip16*/);
-
-               if (fail(pm))
-                  return;
-
-               gamma_transform_test(pm, 2, 16, pm->interlace_type,
-                   1/pm->gammas[i], pm->gammas[j], sbit, speed,
-                   pm->use_input_precision_sbit, 0 /*strip16*/);
-
-               if (fail(pm))
-                  return;
-#endif
-            }
-         }
-      }
-   }
-}
-
-/* Note that this requires a 16 bit source image but produces 8 bit output, so
- * we only need the 16bit write support.
- */
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-static void perform_gamma_strip16_tests(png_modifier *pm, int speed)
-{
-#  ifndef PNG_MAX_GAMMA_8
-#     define PNG_MAX_GAMMA_8 11
-#  endif
-   /* Include the alpha cases here. Note that sbit matches the internal value
-    * used by the library - otherwise we will get spurious errors from the
-    * internal sbit style approximation.
-    *
-    * The threshold test is here because otherwise the 16 to 8 conversion will
-    * proceed *without* gamma correction, and the tests above will fail (but not
-    * by much) - this could be fixed, it only appears with the -g option.
-    */
-   unsigned int i, j;
-   for (i=0; i<pm->ngammas; ++i)
-   {
-      for (j=0; j<pm->ngammas; ++j)
-      {
-         if (i != j &&
-             fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
-         {
-            gamma_transform_test(pm, 0, 16, pm->interlace_type, 1/pm->gammas[i],
-                pm->gammas[j], PNG_MAX_GAMMA_8, speed,
-                pm->use_input_precision_16to8, 1 /*strip16*/);
-
-            if (fail(pm))
-               return;
-
-            gamma_transform_test(pm, 2, 16, pm->interlace_type, 1/pm->gammas[i],
-                pm->gammas[j], PNG_MAX_GAMMA_8, speed,
-                pm->use_input_precision_16to8, 1 /*strip16*/);
-
-            if (fail(pm))
-               return;
-
-            gamma_transform_test(pm, 4, 16, pm->interlace_type, 1/pm->gammas[i],
-                pm->gammas[j], PNG_MAX_GAMMA_8, speed,
-                pm->use_input_precision_16to8, 1 /*strip16*/);
-
-            if (fail(pm))
-               return;
-
-            gamma_transform_test(pm, 6, 16, pm->interlace_type, 1/pm->gammas[i],
-                pm->gammas[j], PNG_MAX_GAMMA_8, speed,
-                pm->use_input_precision_16to8, 1 /*strip16*/);
-
-            if (fail(pm))
-               return;
-         }
-      }
-   }
-}
-#endif /* 16 to 8 bit conversion */
-
-static void
-perform_gamma_test(png_modifier *pm, int speed, int summary)
-{
-   /* First some arbitrary no-transform tests: */
-   if (!speed && pm->test_gamma_threshold)
-   {
-      perform_gamma_threshold_tests(pm);
-
-      if (fail(pm))
-         return;
-   }
-
-   /* Now some real transforms. */
-   if (pm->test_gamma_transform)
-   {
-      perform_gamma_transform_tests(pm, speed);
-
-      if (summary)
-      {
-         printf("Gamma correction error summary\n\n");
-         printf("The printed value is the maximum error in the pixel values\n");
-         printf("calculated by the libpng gamma correction code.  The error\n");
-         printf("is calculated as the difference between the output pixel\n");
-         printf("value (always an integer) and the ideal value from the\n");
-         printf("libpng specification (typically not an integer).\n\n");
-
-         printf("Expect this value to be less than .5 for 8 bit formats,\n");
-         printf("less than 1 for formats with fewer than 8 bits and a small\n");
-         printf("number (typically less than 5) for the 16 bit formats.\n");
-         printf("For performance reasons the value for 16 bit formats\n");
-         printf("increases when the image file includes an sBIT chunk.\n\n");
-
-         printf("  2 bit gray:  %.5f\n", pm->error_gray_2);
-         printf("  4 bit gray:  %.5f\n", pm->error_gray_4);
-         printf("  8 bit gray:  %.5f\n", pm->error_gray_8);
-         printf("  8 bit color: %.5f\n", pm->error_color_8);
-#ifdef DO_16BIT
-         printf(" 16 bit gray:  %.5f\n", pm->error_gray_16);
-         printf(" 16 bit color: %.5f\n", pm->error_color_16);
-#endif
-      }
-   }
-
-   /* The sbit tests produce much larger errors: */
-   if (pm->test_gamma_sbit)
-   {
-      pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 =
-      pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
-      perform_gamma_sbit_tests(pm, speed);
-
-      if (summary)
-      {
-         printf("Gamma correction with sBIT:\n");
-
-         if (pm->sbitlow < 8U)
-         {
-            printf("  2 bit gray:  %.5f\n", pm->error_gray_2);
-            printf("  4 bit gray:  %.5f\n", pm->error_gray_4);
-            printf("  8 bit gray:  %.5f\n", pm->error_gray_8);
-            printf("  8 bit color: %.5f\n", pm->error_color_8);
-         }
-
-   #ifdef DO_16BIT
-         printf(" 16 bit gray:  %.5f\n", pm->error_gray_16);
-         printf(" 16 bit color: %.5f\n", pm->error_color_16);
-   #endif
-      }
-   }
-
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-   if (pm->test_gamma_strip16)
-   {
-      /* The 16 to 8 bit strip operations: */
-      pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 =
-      pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
-      perform_gamma_strip16_tests(pm, speed);
-
-      if (summary)
-      {
-         printf("Gamma correction with 16 to 8 bit reduction:\n");
-         printf(" 16 bit gray:  %.5f\n", pm->error_gray_16);
-         printf(" 16 bit color: %.5f\n", pm->error_color_16);
-      }
-   }
-#endif
-}
-
-/* INTERLACE MACRO VALIDATION */
-/* This is copied verbatim from the specification, it is simply the pass
- * number in which each pixel in each 8x8 tile appears.  The array must
- * be indexed adam7[y][x] and notice that the pass numbers are based at
- * 1, not 0 - the base libpng uses.
- */
-static PNG_CONST
-png_byte adam7[8][8] =
-{
-   { 1,6,4,6,2,6,4,6 },
-   { 7,7,7,7,7,7,7,7 },
-   { 5,6,5,6,5,6,5,6 },
-   { 7,7,7,7,7,7,7,7 },
-   { 3,6,4,6,3,6,4,6 },
-   { 7,7,7,7,7,7,7,7 },
-   { 5,6,5,6,5,6,5,6 },
-   { 7,7,7,7,7,7,7,7 }
-};
-
-/* This routine validates all the interlace support macros in png.h for
- * a variety of valid PNG widths and heights.  It uses a number of similarly
- * named internal routines that feed off the above array.
- */
-static png_uint_32
-png_pass_start_row(int pass)
-{
-   int x, y;
-   ++pass;
-   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
-      return y;
-   return 0xf;
-}
-
-static png_uint_32
-png_pass_start_col(int pass)
-{
-   int x, y;
-   ++pass;
-   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
-      return x;
-   return 0xf;
-}
-
-static int
-png_pass_row_shift(int pass)
-{
-   int x, y, base=(-1), inc=8;
-   ++pass;
-   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
-   {
-      if (base == (-1))
-         base = y;
-      else if (base == y)
-         {}
-      else if (inc == y-base)
-         base=y;
-      else if (inc == 8)
-         inc = y-base, base=y;
-      else if (inc != y-base)
-         return 0xff; /* error - more than one 'inc' value! */
-   }
-
-   if (base == (-1)) return 0xfe; /* error - no row in pass! */
-
-   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
-   switch (inc)
-   {
-case 2: return 1;
-case 4: return 2;
-case 8: return 3;
-default: break;
-   }
-
-   /* error - unrecognized 'inc' */
-   return (inc << 8) + 0xfd;
-}
-
-static int
-png_pass_col_shift(int pass)
-{
-   int x, y, base=(-1), inc=8;
-   ++pass;
-   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
-   {
-      if (base == (-1))
-         base = x;
-      else if (base == x)
-         {}
-      else if (inc == x-base)
-         base=x;
-      else if (inc == 8)
-         inc = x-base, base=x;
-      else if (inc != x-base)
-         return 0xff; /* error - more than one 'inc' value! */
-   }
-
-   if (base == (-1)) return 0xfe; /* error - no row in pass! */
-
-   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
-   switch (inc)
-   {
-case 1: return 0; /* pass 7 has all the columns */
-case 2: return 1;
-case 4: return 2;
-case 8: return 3;
-default: break;
-   }
-
-   /* error - unrecognized 'inc' */
-   return (inc << 8) + 0xfd;
-}
-
-static png_uint_32
-png_row_from_pass_row(png_uint_32 yIn, int pass)
-{
-   /* By examination of the array: */
-   switch (pass)
-   {
-case 0: return yIn * 8;
-case 1: return yIn * 8;
-case 2: return yIn * 8 + 4;
-case 3: return yIn * 4;
-case 4: return yIn * 4 + 2;
-case 5: return yIn * 2;
-case 6: return yIn * 2 + 1;
-default: break;
-   }
-
-   return 0xff; /* bad pass number */
-}
-
-static png_uint_32
-png_col_from_pass_col(png_uint_32 xIn, int pass)
-{
-   /* By examination of the array: */
-   switch (pass)
-   {
-case 0: return xIn * 8;
-case 1: return xIn * 8 + 4;
-case 2: return xIn * 4;
-case 3: return xIn * 4 + 2;
-case 4: return xIn * 2;
-case 5: return xIn * 2 + 1;
-case 6: return xIn;
-default: break;
-   }
-
-   return 0xff; /* bad pass number */
-}
-
-static int
-png_row_in_interlace_pass(png_uint_32 y, int pass)
-{
-   /* Is row 'y' in pass 'pass'? */
-   int x;
-   y &= 7;
-   ++pass;
-   for (x=0; x<8; ++x) if (adam7[y][x] == pass)
-      return 1;
-
-   return 0;
-}
-
-static int
-png_col_in_interlace_pass(png_uint_32 x, int pass)
-{
-   /* Is column 'x' in pass 'pass'? */
-   int y;
-   x &= 7;
-   ++pass;
-   for (y=0; y<8; ++y) if (adam7[y][x] == pass)
-      return 1;
-
-   return 0;
-}
-
-static png_uint_32
-png_pass_rows(png_uint_32 height, int pass)
-{
-   png_uint_32 tiles = height>>3;
-   png_uint_32 rows = 0;
-   unsigned int x, y;
-
-   height &= 7;
-   ++pass;
-   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
-   {
-      rows += tiles;
-      if (y < height) ++rows;
-      break; /* i.e. break the 'x', column, loop. */
-   }
-
-   return rows;
-}
-
-static png_uint_32
-png_pass_cols(png_uint_32 width, int pass)
-{
-   png_uint_32 tiles = width>>3;
-   png_uint_32 cols = 0;
-   unsigned int x, y;
-
-   width &= 7;
-   ++pass;
-   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
-   {
-      cols += tiles;
-      if (x < width) ++cols;
-      break; /* i.e. break the 'y', row, loop. */
-   }
-
-   return cols;
-}
-
-static void
-perform_interlace_macro_validation(void)
-{
-   /* The macros to validate, first those that depend only on pass:
-    *
-    * PNG_PASS_START_ROW(pass)
-    * PNG_PASS_START_COL(pass)
-    * PNG_PASS_ROW_SHIFT(pass)
-    * PNG_PASS_COL_SHIFT(pass)
-    */
-   int pass;
-
-   for (pass=0; pass<7; ++pass)
-   {
-      png_uint_32 m, f, v;
-
-      m = PNG_PASS_START_ROW(pass);
-      f = png_pass_start_row(pass);
-      if (m != f)
-      {
-         fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
-         exit(1);
-      }
-
-      m = PNG_PASS_START_COL(pass);
-      f = png_pass_start_col(pass);
-      if (m != f)
-      {
-         fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
-         exit(1);
-      }
-
-      m = PNG_PASS_ROW_SHIFT(pass);
-      f = png_pass_row_shift(pass);
-      if (m != f)
-      {
-         fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
-         exit(1);
-      }
-
-      m = PNG_PASS_COL_SHIFT(pass);
-      f = png_pass_col_shift(pass);
-      if (m != f)
-      {
-         fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
-         exit(1);
-      }
-
-      /* Macros that depend on the image or sub-image height too:
-       *
-       * PNG_PASS_ROWS(height, pass)
-       * PNG_PASS_COLS(width, pass)
-       * PNG_ROW_FROM_PASS_ROW(yIn, pass)
-       * PNG_COL_FROM_PASS_COL(xIn, pass)
-       * PNG_ROW_IN_INTERLACE_PASS(y, pass)
-       * PNG_COL_IN_INTERLACE_PASS(x, pass)
-       */
-      for (v=0;;)
-      {
-         /* First the base 0 stuff: */
-         m = PNG_ROW_FROM_PASS_ROW(v, pass);
-         f = png_row_from_pass_row(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         m = PNG_COL_FROM_PASS_COL(v, pass);
-         f = png_col_from_pass_col(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
-         f = png_row_in_interlace_pass(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         m = PNG_COL_IN_INTERLACE_PASS(v, pass);
-         f = png_col_in_interlace_pass(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         /* Then the base 1 stuff: */
-         ++v;
-         m = PNG_PASS_ROWS(v, pass);
-         f = png_pass_rows(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         m = PNG_PASS_COLS(v, pass);
-         f = png_pass_cols(v, pass);
-         if (m != f)
-         {
-            fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
-               v, pass, m, f);
-            exit(1);
-         }
-
-         /* Move to the next v - the stepping algorithm starts skipping
-          * values above 1024.
-          */
-         if (v > 1024)
-         {
-            if (v == PNG_UINT_31_MAX)
-               break;
-
-            v = (v << 1) ^ v;
-            if (v >= PNG_UINT_31_MAX)
-               v = PNG_UINT_31_MAX-1;
-         }
-      }
-   }
-}
-
-/* main program */
-int main(int argc, PNG_CONST char **argv)
-{
-   volatile int summary = 1;  /* Print the error summary at the end */
-
-   /* Create the given output file on success: */
-   PNG_CONST char *volatile touch = NULL;
-
-   /* This is an array of standard gamma values (believe it or not I've seen
-    * every one of these mentioned somewhere.)
-    *
-    * In the following list the most useful values are first!
-    */
-   static double
-      gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
-
-   png_modifier pm;
-   context(&pm.this, fault);
-
-   modifier_init(&pm);
-
-   /* Preallocate the image buffer, because we know how big it needs to be,
-    * note that, for testing purposes, it is deliberately mis-aligned.
-    */
-   pm.this.image = malloc(2*TRANSFORM_IMAGEMAX+1);
-
-   if (pm.this.image != NULL)
-   {
-      /* Ignore OOM at this point - the 'ensure' routine above will allocate
-       * the array appropriately.
-       */
-      ++(pm.this.image);
-      pm.this.cb_image = 2*TRANSFORM_IMAGEMAX;
-   }
-
-   /* Default to error on warning: */
-   pm.this.treat_warnings_as_errors = 1;
-
-   /* Store the test gammas */
-   pm.gammas = gammas;
-   pm.ngammas = 0; /* default to off */
-   pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
-   pm.use_input_precision_16to8 = 1U; /* Because of the way libpng does it */
-
-   /* Some default values (set the behavior for 'make check' here).
-    * These values simply control the maximum error permitted in the gamma
-    * transformations.  The practial limits for human perception are described
-    * below (the setting for maxpc16), however for 8 bit encodings it isn't
-    * possible to meet the accepted capabilities of human vision - i.e. 8 bit
-    * images can never be good enough, regardless of encoding.
-    */
-   pm.maxout8 = .1;     /* Arithmetic error in *encoded* value */
-   pm.maxabs8 = .00005; /* 1/20000 */
-   pm.maxpc8 = .499;    /* I.e., .499% fractional error */
-   pm.maxout16 = .499;  /* Error in *encoded* value */
-   pm.maxabs16 = .00005;/* 1/20000 */
-
-   /* NOTE: this is a reasonable perceptual limit. We assume that humans can
-    * perceive light level differences of 1% over a 100:1 range, so we need to
-    * maintain 1 in 10000 accuracy (in linear light space), which is what the
-    * following guarantees.  It also allows significantly higher errors at
-    * higher 16 bit values, which is important for performance.  The actual
-    * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
-    * this is only allowed for values >38149 by the following:
-    */
-   pm.maxpc16 = .005;   /* I.e., 1/200% - 1/20000 */
-
-   /* Now parse the command line options. */
-   while (--argc >= 1)
-   {
-      if (strcmp(*++argv, "-v") == 0)
-         pm.this.verbose = 1;
-
-      else if (strcmp(*argv, "-l") == 0)
-         pm.log = 1;
-
-      else if (strcmp(*argv, "-q") == 0)
-         summary = pm.this.verbose = pm.log = 0;
-
-      else if (strcmp(*argv, "-w") == 0)
-         pm.this.treat_warnings_as_errors = 0;
-
-      else if (strcmp(*argv, "--speed") == 0)
-         pm.this.speed = 1, pm.ngammas = (sizeof gammas)/(sizeof gammas[0]),
-            pm.test_standard = 0;
-
-      else if (strcmp(*argv, "--size") == 0)
-         pm.test_size = 1;
-
-      else if (strcmp(*argv, "--nosize") == 0)
-         pm.test_size = 0;
-
-      else if (strcmp(*argv, "--standard") == 0)
-         pm.test_standard = 1;
-
-      else if (strcmp(*argv, "--nostandard") == 0)
-         pm.test_standard = 0;
-
-      else if (strcmp(*argv, "--transform") == 0)
-         pm.test_transform = 1;
-
-      else if (strcmp(*argv, "--notransform") == 0)
-         pm.test_transform = 0;
-
-      else if (strncmp(*argv, "--transform-disable=",
-         sizeof "--transform-disable") == 0)
-         {
-         pm.test_transform = 1;
-         transform_disable(*argv + sizeof "--transform-disable");
-         }
-
-      else if (strncmp(*argv, "--transform-enable=",
-         sizeof "--transform-enable") == 0)
-         {
-         pm.test_transform = 1;
-         transform_enable(*argv + sizeof "--transform-enable");
-         }
-
-      else if (strcmp(*argv, "--gamma") == 0)
-         {
-         /* Just do two gamma tests here (2.2 and linear) for speed: */
-         pm.ngammas = 2U;
-         pm.test_gamma_threshold = 1;
-         pm.test_gamma_transform = 1;
-         pm.test_gamma_sbit = 1;
-         pm.test_gamma_strip16 = 1;
-         }
-
-      else if (strcmp(*argv, "--nogamma") == 0)
-         pm.ngammas = 0;
-
-      else if (strcmp(*argv, "--gamma-threshold") == 0)
-         pm.ngammas = 2U, pm.test_gamma_threshold = 1;
-
-      else if (strcmp(*argv, "--nogamma-threshold") == 0)
-         pm.test_gamma_threshold = 0;
-
-      else if (strcmp(*argv, "--gamma-transform") == 0)
-         pm.ngammas = 2U, pm.test_gamma_transform = 1;
-
-      else if (strcmp(*argv, "--nogamma-transform") == 0)
-         pm.test_gamma_transform = 0;
-
-      else if (strcmp(*argv, "--gamma-sbit") == 0)
-         pm.ngammas = 2U, pm.test_gamma_sbit = 1;
-
-      else if (strcmp(*argv, "--nogamma-sbit") == 0)
-         pm.test_gamma_sbit = 0;
-
-      else if (strcmp(*argv, "--gamma-16-to-8") == 0)
-         pm.ngammas = 2U, pm.test_gamma_strip16 = 1;
-
-      else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
-         pm.test_gamma_strip16 = 0;
-
-      else if (strcmp(*argv, "--all-gammas") == 0)
-         pm.ngammas = (sizeof gammas)/(sizeof gammas[0]);
-
-      else if (strcmp(*argv, "--progressive-read") == 0)
-         pm.this.progressive = 1;
-
-      else if (strcmp(*argv, "--interlace") == 0)
-         pm.interlace_type = PNG_INTERLACE_ADAM7;
-
-      else if (argc >= 1 && strcmp(*argv, "--sbitlow") == 0)
-         --argc, pm.sbitlow = (png_byte)atoi(*++argv);
-
-      else if (argc >= 1 && strcmp(*argv, "--touch") == 0)
-         --argc, touch = *++argv;
-
-      else if (argc >= 1 && strncmp(*argv, "--max", 4) == 0)
-      {
-         --argc;
-
-         if (strcmp(4+*argv, "abs8") == 0)
-            pm.maxabs8 = atof(*++argv);
-
-         else if (strcmp(4+*argv, "abs16") == 0)
-            pm.maxabs16 = atof(*++argv);
-
-         else if (strcmp(4+*argv, "out8") == 0)
-            pm.maxout8 = atof(*++argv);
-
-         else if (strcmp(4+*argv, "out16") == 0)
-            pm.maxout16 = atof(*++argv);
-
-         else if (strcmp(4+*argv, "pc8") == 0)
-            pm.maxpc8 = atof(*++argv);
-
-         else if (strcmp(4+*argv, "pc16") == 0)
-            pm.maxpc16 = atof(*++argv);
-
-         else
-         {
-            fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
-            exit(1);
-         }
-      }
-
-      else
-      {
-         fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
-         exit(1);
-      }
-   }
-
-   /* If pngvalid is run with no arguments default to a reasonable set of the
-    * tests.
-    */
-   if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
-      pm.ngammas == 0)
-   {
-      pm.test_standard = 1;
-      pm.test_size = 1;
-      pm.test_transform = 1;
-      pm.ngammas = 3U;
-   }
-
-   if (pm.ngammas > 0 &&
-      pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
-      pm.test_gamma_sbit == 0 && pm.test_gamma_strip16 == 0)
-   {
-      pm.test_gamma_threshold = 1;
-      pm.test_gamma_transform = 1;
-      pm.test_gamma_sbit = 1;
-      pm.test_gamma_strip16 = 1;
-   }
-   
-   else if (pm.ngammas == 0)
-   {
-      /* Nothing to test so turn everything off: */
-      pm.test_gamma_threshold = 0;
-      pm.test_gamma_transform = 0;
-      pm.test_gamma_sbit = 0;
-      pm.test_gamma_strip16 = 0;
-   }
-
-   Try
-   {
-      /* Make useful base images */
-      make_transform_images(&pm.this);
-
-      /* Perform the standard and gamma tests. */
-      if (pm.test_standard)
-      {
-         perform_interlace_macro_validation();
-         perform_standard_test(&pm);
-         perform_error_test(&pm);
-      }
-
-      /* Various oddly sized images: */
-      if (pm.test_size)
-      {
-         make_size_images(&pm.this);
-         perform_size_test(&pm);
-      }
-
-      /* Combinatorial transforms: */
-      if (pm.test_transform)
-         perform_transform_test(&pm);
-
-      if (pm.ngammas > 0)
-         perform_gamma_test(&pm, pm.this.speed != 0,
-            summary && !pm.this.speed);
-   }
-
-   Catch(fault)
-   {
-      fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
-      if (!pm.this.verbose)
-      {
-         if (pm.this.error[0] != 0)
-            fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
-
-         fprintf(stderr, "pngvalid: run with -v to see what happened\n");
-      }
-      exit(1);
-   }
-
-   if (summary && !pm.this.speed)
-   {
-      printf("Results using %s point arithmetic %s\n",
-#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
-         "floating",
-#else
-         "fixed",
-#endif
-         (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
-            pm.this.nwarnings)) ? "(errors)" : (pm.this.nwarnings ?
-               "(warnings)" : "(no errors or warnings)")
-      );
-      printf("Allocated memory statistics (in bytes):\n"
-         "\tread  %lu maximum single, %lu peak, %lu total\n"
-         "\twrite %lu maximum single, %lu peak, %lu total\n",
-         (unsigned long)pm.this.read_memory_pool.max_max,
-         (unsigned long)pm.this.read_memory_pool.max_limit,
-         (unsigned long)pm.this.read_memory_pool.max_total,
-         (unsigned long)pm.this.write_memory_pool.max_max,
-         (unsigned long)pm.this.write_memory_pool.max_limit,
-         (unsigned long)pm.this.write_memory_pool.max_total);
-   }
-
-   /* Do this here to provoke memory corruption errors in memory not directly
-    * allocated by libpng - not a complete test, but better than nothing.
-    */
-   store_delete(&pm.this);
-
-   /* Error exit if there are any errors, and maybe if there are any
-    * warnings.
-    */
-   if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
-       pm.this.nwarnings))
-   {
-      if (!pm.this.verbose)
-         fprintf(stderr, "pngvalid: %s\n", pm.this.error);
-
-      fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
-          pm.this.nwarnings);
-
-      exit(1);
-   }
-
-   /* Success case. */
-   if (touch != NULL)
-   {
-      FILE *fsuccess = fopen(touch, "wt");
-
-      if (fsuccess != NULL)
-      {
-         int error = 0;
-         fprintf(fsuccess, "PNG validation succeeded\n");
-         fflush(fsuccess);
-         error = ferror(fsuccess);
-
-         if (fclose(fsuccess) || error)
-         {
-            fprintf(stderr, "%s: write failed\n", touch);
-            exit(1);
-         }
-      }
-   }
-
-   return 0;
-}
diff --git a/extern/libpng/include/pngwio.c b/extern/libpng/include/pngwio.c
deleted file mode 100644
index 95ffb3429f..0000000000
--- a/extern/libpng/include/pngwio.c
+++ /dev/null
@@ -1,254 +0,0 @@
-
-/* pngwio.c - functions for data output
- *
- * Last changed in libpng 1.5.0 [January 6, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * This file provides a location for all output.  Users who need
- * special handling are expected to write functions that have the same
- * arguments as these and perform similar functions, but that possibly
- * use different output methods.  Note that you shouldn't change these
- * functions, but rather write replacement functions and then change
- * them at run time with png_set_write_fn(...).
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_WRITE_SUPPORTED
-
-/* Write the data to whatever output you are using.  The default routine
- * writes to a file pointer.  Note that this routine sometimes gets called
- * with very small lengths, so you should implement some kind of simple
- * buffering if you are using unbuffered writes.  This should never be asked
- * to write more than 64K on a 16 bit machine.
- */
-
-void /* PRIVATE */
-png_write_data(png_structp png_ptr, png_const_bytep data, png_size_t length)
-{
-   /* NOTE: write_data_fn must not change the buffer! */
-   if (png_ptr->write_data_fn != NULL )
-      (*(png_ptr->write_data_fn))(png_ptr, (png_bytep)data, length);
-
-   else
-      png_error(png_ptr, "Call to NULL write function");
-}
-
-#ifdef PNG_STDIO_SUPPORTED
-/* This is the function that does the actual writing of data.  If you are
- * not writing to a standard C stream, you should create a replacement
- * write_data function and use it at run time with png_set_write_fn(), rather
- * than changing the library.
- */
-#ifndef USE_FAR_KEYWORD
-void PNGCBAPI
-png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_size_t check;
-
-   if (png_ptr == NULL)
-      return;
-
-   check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
-
-   if (check != length)
-      png_error(png_ptr, "Write Error");
-}
-#else
-/* This is the model-independent version. Since the standard I/O library
- * can't handle far buffers in the medium and small models, we have to copy
- * the data.
- */
-
-#define NEAR_BUF_SIZE 1024
-#define MIN(a,b) (a <= b ? a : b)
-
-void PNGCBAPI
-png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_uint_32 check;
-   png_byte *near_data;  /* Needs to be "png_byte *" instead of "png_bytep" */
-   png_FILE_p io_ptr;
-
-   if (png_ptr == NULL)
-      return;
-
-   /* Check if data really is near. If so, use usual code. */
-   near_data = (png_byte *)CVT_PTR_NOCHECK(data);
-   io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
-
-   if ((png_bytep)near_data == data)
-   {
-      check = fwrite(near_data, 1, length, io_ptr);
-   }
-
-   else
-   {
-      png_byte buf[NEAR_BUF_SIZE];
-      png_size_t written, remaining, err;
-      check = 0;
-      remaining = length;
-
-      do
-      {
-         written = MIN(NEAR_BUF_SIZE, remaining);
-         png_memcpy(buf, data, written); /* Copy far buffer to near buffer */
-         err = fwrite(buf, 1, written, io_ptr);
-
-         if (err != written)
-            break;
-
-         else
-            check += err;
-
-         data += written;
-         remaining -= written;
-      }
-      while (remaining != 0);
-   }
-
-   if (check != length)
-      png_error(png_ptr, "Write Error");
-}
-
-#endif
-#endif
-
-/* This function is called to output any data pending writing (normally
- * to disk).  After png_flush is called, there should be no data pending
- * writing in any buffers.
- */
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-void /* PRIVATE */
-png_flush(png_structp png_ptr)
-{
-   if (png_ptr->output_flush_fn != NULL)
-      (*(png_ptr->output_flush_fn))(png_ptr);
-}
-
-#  ifdef PNG_STDIO_SUPPORTED
-void PNGCBAPI
-png_default_flush(png_structp png_ptr)
-{
-   png_FILE_p io_ptr;
-
-   if (png_ptr == NULL)
-      return;
-
-   io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
-   fflush(io_ptr);
-}
-#  endif
-#endif
-
-/* This function allows the application to supply new output functions for
- * libpng if standard C streams aren't being used.
- *
- * This function takes as its arguments:
- * png_ptr       - pointer to a png output data structure
- * io_ptr        - pointer to user supplied structure containing info about
- *                 the output functions.  May be NULL.
- * write_data_fn - pointer to a new output function that takes as its
- *                 arguments a pointer to a png_struct, a pointer to
- *                 data to be written, and a 32-bit unsigned int that is
- *                 the number of bytes to be written.  The new write
- *                 function should call png_error(png_ptr, "Error msg")
- *                 to exit and output any fatal error messages.  May be
- *                 NULL, in which case libpng's default function will
- *                 be used.
- * flush_data_fn - pointer to a new flush function that takes as its
- *                 arguments a pointer to a png_struct.  After a call to
- *                 the flush function, there should be no data in any buffers
- *                 or pending transmission.  If the output method doesn't do
- *                 any buffering of output, a function prototype must still be
- *                 supplied although it doesn't have to do anything.  If
- *                 PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
- *                 time, output_flush_fn will be ignored, although it must be
- *                 supplied for compatibility.  May be NULL, in which case
- *                 libpng's default function will be used, if
- *                 PNG_WRITE_FLUSH_SUPPORTED is defined.  This is not
- *                 a good idea if io_ptr does not point to a standard
- *                 *FILE structure.
- */
-void PNGAPI
-png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
-    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
-{
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->io_ptr = io_ptr;
-
-#ifdef PNG_STDIO_SUPPORTED
-   if (write_data_fn != NULL)
-      png_ptr->write_data_fn = write_data_fn;
-
-   else
-      png_ptr->write_data_fn = png_default_write_data;
-#else
-   png_ptr->write_data_fn = write_data_fn;
-#endif
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-#  ifdef PNG_STDIO_SUPPORTED
-
-   if (output_flush_fn != NULL)
-      png_ptr->output_flush_fn = output_flush_fn;
-
-   else
-      png_ptr->output_flush_fn = png_default_flush;
-
-#  else
-   png_ptr->output_flush_fn = output_flush_fn;
-#  endif
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
-
-   /* It is an error to read while writing a png file */
-   if (png_ptr->read_data_fn != NULL)
-   {
-      png_ptr->read_data_fn = NULL;
-
-      png_warning(png_ptr,
-          "Can't set both read_data_fn and write_data_fn in the"
-          " same structure");
-   }
-}
-
-#ifdef USE_FAR_KEYWORD
-#  ifdef _MSC_VER
-void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)
-{
-   void *near_ptr;
-   void FAR *far_ptr;
-   FP_OFF(near_ptr) = FP_OFF(ptr);
-   far_ptr = (void FAR *)near_ptr;
-
-   if (check != 0)
-      if (FP_SEG(ptr) != FP_SEG(far_ptr))
-         png_error(png_ptr, "segment lost in conversion");
-
-   return(near_ptr);
-}
-#  else
-void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)
-{
-   void *near_ptr;
-   void FAR *far_ptr;
-   near_ptr = (void FAR *)ptr;
-   far_ptr = (void FAR *)near_ptr;
-
-   if (check != 0)
-      if (far_ptr != ptr)
-         png_error(png_ptr, "segment lost in conversion");
-
-   return(near_ptr);
-}
-#  endif
-#endif
-#endif /* PNG_WRITE_SUPPORTED */
diff --git a/extern/libpng/include/pngwrite.c b/extern/libpng/include/pngwrite.c
deleted file mode 100644
index b587f1b999..0000000000
--- a/extern/libpng/include/pngwrite.c
+++ /dev/null
@@ -1,1667 +0,0 @@
-
-/* pngwrite.c - general routines to write a PNG file
- *
- * Last changed in libpng 1.5.10 [March 8, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_WRITE_SUPPORTED
-
-/* Writes all the PNG information.  This is the suggested way to use the
- * library.  If you have a new chunk to add, make a function to write it,
- * and put it in the correct location here.  If you want the chunk written
- * after the image data, put it in png_write_end().  I strongly encourage
- * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
- * the chunk, as that will keep the code from breaking if you want to just
- * write a plain PNG file.  If you have long comments, I suggest writing
- * them in png_write_end(), and compressing them.
- */
-void PNGAPI
-png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)
-{
-   png_debug(1, "in png_write_info_before_PLTE");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
-   {
-   /* Write PNG signature */
-   png_write_sig(png_ptr);
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) && \
-       (png_ptr->mng_features_permitted))
-   {
-      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
-      png_ptr->mng_features_permitted = 0;
-   }
-#endif
-
-   /* Write IHDR information. */
-   png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
-       info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
-       info_ptr->filter_type,
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-       info_ptr->interlace_type);
-#else
-       0);
-#endif
-   /* The rest of these check to see if the valid field has the appropriate
-    * flag set, and if it does, writes the chunk.
-    */
-#ifdef PNG_WRITE_gAMA_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_gAMA)
-      png_write_gAMA_fixed(png_ptr, info_ptr->gamma);
-#endif
-#ifdef PNG_WRITE_sRGB_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sRGB)
-      png_write_sRGB(png_ptr, (int)info_ptr->srgb_intent);
-#endif
-
-#ifdef PNG_WRITE_iCCP_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_iCCP)
-      png_write_iCCP(png_ptr, info_ptr->iccp_name, PNG_COMPRESSION_TYPE_BASE,
-          (png_charp)info_ptr->iccp_profile, (int)info_ptr->iccp_proflen);
-#endif
-#ifdef PNG_WRITE_sBIT_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sBIT)
-      png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
-#endif
-#ifdef PNG_WRITE_cHRM_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_cHRM)
-      png_write_cHRM_fixed(png_ptr,
-          info_ptr->x_white, info_ptr->y_white,
-          info_ptr->x_red, info_ptr->y_red,
-          info_ptr->x_green, info_ptr->y_green,
-          info_ptr->x_blue, info_ptr->y_blue);
-#endif
-
-#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-   if (info_ptr->unknown_chunks_num)
-   {
-      png_unknown_chunk *up;
-
-      png_debug(5, "writing extra chunks");
-
-      for (up = info_ptr->unknown_chunks;
-           up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
-           up++)
-      {
-         int keep = png_handle_as_unknown(png_ptr, up->name);
-
-         if (keep != PNG_HANDLE_CHUNK_NEVER &&
-             up->location &&
-             !(up->location & PNG_HAVE_PLTE) &&
-             !(up->location & PNG_HAVE_IDAT) &&
-             !(up->location & PNG_AFTER_IDAT) &&
-             ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
-             (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
-         {
-            if (up->size == 0)
-               png_warning(png_ptr, "Writing zero-length unknown chunk");
-
-            png_write_chunk(png_ptr, up->name, up->data, up->size);
-         }
-      }
-   }
-#endif
-      png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
-   }
-}
-
-void PNGAPI
-png_write_info(png_structp png_ptr, png_infop info_ptr)
-{
-#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
-   int i;
-#endif
-
-   png_debug(1, "in png_write_info");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   png_write_info_before_PLTE(png_ptr, info_ptr);
-
-   if (info_ptr->valid & PNG_INFO_PLTE)
-      png_write_PLTE(png_ptr, info_ptr->palette,
-          (png_uint_32)info_ptr->num_palette);
-
-   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      png_error(png_ptr, "Valid palette required for paletted images");
-
-#ifdef PNG_WRITE_tRNS_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_tRNS)
-   {
-#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-      /* Invert the alpha channel (in tRNS) */
-      if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
-          info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         int j;
-         for (j = 0; j<(int)info_ptr->num_trans; j++)
-            info_ptr->trans_alpha[j] =
-               (png_byte)(255 - info_ptr->trans_alpha[j]);
-      }
-#endif
-      png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
-          info_ptr->num_trans, info_ptr->color_type);
-   }
-#endif
-#ifdef PNG_WRITE_bKGD_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_bKGD)
-      png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
-#endif
-
-#ifdef PNG_WRITE_hIST_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_hIST)
-      png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
-#endif
-
-#ifdef PNG_WRITE_oFFs_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_oFFs)
-      png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
-          info_ptr->offset_unit_type);
-#endif
-
-#ifdef PNG_WRITE_pCAL_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_pCAL)
-      png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
-          info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
-          info_ptr->pcal_units, info_ptr->pcal_params);
-#endif
-
-#ifdef PNG_WRITE_sCAL_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sCAL)
-      png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
-          info_ptr->scal_s_width, info_ptr->scal_s_height);
-#endif /* sCAL */
-
-#ifdef PNG_WRITE_pHYs_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_pHYs)
-      png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
-          info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
-#endif /* pHYs */
-
-#ifdef PNG_WRITE_tIME_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_tIME)
-   {
-      png_write_tIME(png_ptr, &(info_ptr->mod_time));
-      png_ptr->mode |= PNG_WROTE_tIME;
-   }
-#endif /* tIME */
-
-#ifdef PNG_WRITE_sPLT_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sPLT)
-      for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
-         png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
-#endif /* sPLT */
-
-#ifdef PNG_WRITE_TEXT_SUPPORTED
-   /* Check to see if we need to write text chunks */
-   for (i = 0; i < info_ptr->num_text; i++)
-   {
-      png_debug2(2, "Writing header text chunk %d, type %d", i,
-          info_ptr->text[i].compression);
-      /* An internationalized chunk? */
-      if (info_ptr->text[i].compression > 0)
-      {
-#ifdef PNG_WRITE_iTXt_SUPPORTED
-         /* Write international chunk */
-         png_write_iTXt(png_ptr,
-             info_ptr->text[i].compression,
-             info_ptr->text[i].key,
-             info_ptr->text[i].lang,
-             info_ptr->text[i].lang_key,
-             info_ptr->text[i].text);
-#else
-          png_warning(png_ptr, "Unable to write international text");
-#endif
-          /* Mark this chunk as written */
-          info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
-      }
-
-      /* If we want a compressed text chunk */
-      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
-      {
-#ifdef PNG_WRITE_zTXt_SUPPORTED
-         /* Write compressed chunk */
-         png_write_zTXt(png_ptr, info_ptr->text[i].key,
-             info_ptr->text[i].text, 0,
-             info_ptr->text[i].compression);
-#else
-         png_warning(png_ptr, "Unable to write compressed text");
-#endif
-         /* Mark this chunk as written */
-         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
-      }
-
-      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
-      {
-#ifdef PNG_WRITE_tEXt_SUPPORTED
-         /* Write uncompressed chunk */
-         png_write_tEXt(png_ptr, info_ptr->text[i].key,
-             info_ptr->text[i].text,
-             0);
-         /* Mark this chunk as written */
-         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
-#else
-         /* Can't get here */
-         png_warning(png_ptr, "Unable to write uncompressed text");
-#endif
-      }
-   }
-#endif /* tEXt */
-
-#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-   if (info_ptr->unknown_chunks_num)
-   {
-      png_unknown_chunk *up;
-
-      png_debug(5, "writing extra chunks");
-
-      for (up = info_ptr->unknown_chunks;
-           up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
-           up++)
-      {
-         int keep = png_handle_as_unknown(png_ptr, up->name);
-         if (keep != PNG_HANDLE_CHUNK_NEVER &&
-             up->location &&
-             (up->location & PNG_HAVE_PLTE) &&
-             !(up->location & PNG_HAVE_IDAT) &&
-             !(up->location & PNG_AFTER_IDAT) &&
-             ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
-             (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
-         {
-            png_write_chunk(png_ptr, up->name, up->data, up->size);
-         }
-      }
-   }
-#endif
-}
-
-/* Writes the end of the PNG file.  If you don't want to write comments or
- * time information, you can pass NULL for info.  If you already wrote these
- * in png_write_info(), do not write them again here.  If you have long
- * comments, I suggest writing them here, and compressing them.
- */
-void PNGAPI
-png_write_end(png_structp png_ptr, png_infop info_ptr)
-{
-   png_debug(1, "in png_write_end");
-
-   if (png_ptr == NULL)
-      return;
-
-   if (!(png_ptr->mode & PNG_HAVE_IDAT))
-      png_error(png_ptr, "No IDATs written into file");
-
-#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
-   if (png_ptr->num_palette_max > png_ptr->num_palette)
-      png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
-#endif
-
-   /* See if user wants us to write information chunks */
-   if (info_ptr != NULL)
-   {
-#ifdef PNG_WRITE_TEXT_SUPPORTED
-      int i; /* local index variable */
-#endif
-#ifdef PNG_WRITE_tIME_SUPPORTED
-      /* Check to see if user has supplied a time chunk */
-      if ((info_ptr->valid & PNG_INFO_tIME) &&
-          !(png_ptr->mode & PNG_WROTE_tIME))
-         png_write_tIME(png_ptr, &(info_ptr->mod_time));
-
-#endif
-#ifdef PNG_WRITE_TEXT_SUPPORTED
-      /* Loop through comment chunks */
-      for (i = 0; i < info_ptr->num_text; i++)
-      {
-         png_debug2(2, "Writing trailer text chunk %d, type %d", i,
-            info_ptr->text[i].compression);
-         /* An internationalized chunk? */
-         if (info_ptr->text[i].compression > 0)
-         {
-#ifdef PNG_WRITE_iTXt_SUPPORTED
-            /* Write international chunk */
-            png_write_iTXt(png_ptr,
-                info_ptr->text[i].compression,
-                info_ptr->text[i].key,
-                info_ptr->text[i].lang,
-                info_ptr->text[i].lang_key,
-                info_ptr->text[i].text);
-#else
-            png_warning(png_ptr, "Unable to write international text");
-#endif
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
-         }
-
-         else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
-         {
-#ifdef PNG_WRITE_zTXt_SUPPORTED
-            /* Write compressed chunk */
-            png_write_zTXt(png_ptr, info_ptr->text[i].key,
-                info_ptr->text[i].text, 0,
-                info_ptr->text[i].compression);
-#else
-            png_warning(png_ptr, "Unable to write compressed text");
-#endif
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
-         }
-
-         else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
-         {
-#ifdef PNG_WRITE_tEXt_SUPPORTED
-            /* Write uncompressed chunk */
-            png_write_tEXt(png_ptr, info_ptr->text[i].key,
-                info_ptr->text[i].text, 0);
-#else
-            png_warning(png_ptr, "Unable to write uncompressed text");
-#endif
-
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
-         }
-      }
-#endif
-#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-   if (info_ptr->unknown_chunks_num)
-   {
-      png_unknown_chunk *up;
-
-      png_debug(5, "writing extra chunks");
-
-      for (up = info_ptr->unknown_chunks;
-           up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
-           up++)
-      {
-         int keep = png_handle_as_unknown(png_ptr, up->name);
-         if (keep != PNG_HANDLE_CHUNK_NEVER &&
-             up->location &&
-             (up->location & PNG_AFTER_IDAT) &&
-             ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
-             (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
-         {
-            png_write_chunk(png_ptr, up->name, up->data, up->size);
-         }
-      }
-   }
-#endif
-   }
-
-   png_ptr->mode |= PNG_AFTER_IDAT;
-
-   /* Write end of PNG file */
-   png_write_IEND(png_ptr);
-   /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
-    * and restored again in libpng-1.2.30, may cause some applications that
-    * do not set png_ptr->output_flush_fn to crash.  If your application
-    * experiences a problem, please try building libpng with
-    * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
-    * png-mng-implement at lists.sf.net .
-    */
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-#  ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
-   png_flush(png_ptr);
-#  endif
-#endif
-}
-
-#ifdef PNG_CONVERT_tIME_SUPPORTED
-/* "tm" structure is not supported on WindowsCE */
-void PNGAPI
-png_convert_from_struct_tm(png_timep ptime, PNG_CONST struct tm FAR * ttime)
-{
-   png_debug(1, "in png_convert_from_struct_tm");
-
-   ptime->year = (png_uint_16)(1900 + ttime->tm_year);
-   ptime->month = (png_byte)(ttime->tm_mon + 1);
-   ptime->day = (png_byte)ttime->tm_mday;
-   ptime->hour = (png_byte)ttime->tm_hour;
-   ptime->minute = (png_byte)ttime->tm_min;
-   ptime->second = (png_byte)ttime->tm_sec;
-}
-
-void PNGAPI
-png_convert_from_time_t(png_timep ptime, time_t ttime)
-{
-   struct tm *tbuf;
-
-   png_debug(1, "in png_convert_from_time_t");
-
-   tbuf = gmtime(&ttime);
-   png_convert_from_struct_tm(ptime, tbuf);
-}
-#endif
-
-/* Initialize png_ptr structure, and allocate any memory needed */
-PNG_FUNCTION(png_structp,PNGAPI
-png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
-    png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
-{
-#ifdef PNG_USER_MEM_SUPPORTED
-   return (png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
-       warn_fn, NULL, NULL, NULL));
-}
-
-/* Alternate initialize png_ptr structure, and allocate any memory needed */
-static void png_reset_filter_heuristics(png_structp png_ptr); /* forward decl */
-
-PNG_FUNCTION(png_structp,PNGAPI
-png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
-    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
-    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
-{
-#endif /* PNG_USER_MEM_SUPPORTED */
-   volatile int png_cleanup_needed = 0;
-#ifdef PNG_SETJMP_SUPPORTED
-   volatile
-#endif
-   png_structp png_ptr;
-#ifdef PNG_SETJMP_SUPPORTED
-#ifdef USE_FAR_KEYWORD
-   jmp_buf tmp_jmpbuf;
-#endif
-#endif
-
-   png_debug(1, "in png_create_write_struct");
-
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
-       (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
-#else
-   png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
-#endif /* PNG_USER_MEM_SUPPORTED */
-   if (png_ptr == NULL)
-      return (NULL);
-
-   /* Added at libpng-1.2.6 */
-#ifdef PNG_SET_USER_LIMITS_SUPPORTED
-   png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
-   png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
-#endif
-
-#ifdef PNG_SETJMP_SUPPORTED
-/* Applications that neglect to set up their own setjmp() and then
- * encounter a png_error() will longjmp here.  Since the jmpbuf is
- * then meaningless we abort instead of returning.
- */
-#ifdef USE_FAR_KEYWORD
-   if (setjmp(tmp_jmpbuf))
-#else
-   if (setjmp(png_jmpbuf(png_ptr))) /* sets longjmp to match setjmp */
-#endif
-#ifdef USE_FAR_KEYWORD
-   png_memcpy(png_jmpbuf(png_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
-#endif
-      PNG_ABORT();
-#endif
-
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
-#endif /* PNG_USER_MEM_SUPPORTED */
-   png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
-
-   if (!png_user_version_check(png_ptr, user_png_ver))
-      png_cleanup_needed = 1;
-
-   /* Initialize zbuf - compression buffer */
-   png_ptr->zbuf_size = PNG_ZBUF_SIZE;
-
-   if (!png_cleanup_needed)
-   {
-      png_ptr->zbuf = (png_bytep)png_malloc_warn(png_ptr,
-          png_ptr->zbuf_size);
-      if (png_ptr->zbuf == NULL)
-         png_cleanup_needed = 1;
-   }
-
-   if (png_cleanup_needed)
-   {
-       /* Clean up PNG structure and deallocate any memory. */
-       png_free(png_ptr, png_ptr->zbuf);
-       png_ptr->zbuf = NULL;
-#ifdef PNG_USER_MEM_SUPPORTED
-       png_destroy_struct_2((png_voidp)png_ptr,
-           (png_free_ptr)free_fn, (png_voidp)mem_ptr);
-#else
-       png_destroy_struct((png_voidp)png_ptr);
-#endif
-       return (NULL);
-   }
-
-   png_set_write_fn(png_ptr, NULL, NULL, NULL);
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   png_reset_filter_heuristics(png_ptr);
-#endif
-
-   return (png_ptr);
-}
-
-
-/* Write a few rows of image data.  If the image is interlaced,
- * either you will have to write the 7 sub images, or, if you
- * have called png_set_interlace_handling(), you will have to
- * "write" the image seven times.
- */
-void PNGAPI
-png_write_rows(png_structp png_ptr, png_bytepp row,
-    png_uint_32 num_rows)
-{
-   png_uint_32 i; /* row counter */
-   png_bytepp rp; /* row pointer */
-
-   png_debug(1, "in png_write_rows");
-
-   if (png_ptr == NULL)
-      return;
-
-   /* Loop through the rows */
-   for (i = 0, rp = row; i < num_rows; i++, rp++)
-   {
-      png_write_row(png_ptr, *rp);
-   }
-}
-
-/* Write the image.  You only need to call this function once, even
- * if you are writing an interlaced image.
- */
-void PNGAPI
-png_write_image(png_structp png_ptr, png_bytepp image)
-{
-   png_uint_32 i; /* row index */
-   int pass, num_pass; /* pass variables */
-   png_bytepp rp; /* points to current row */
-
-   if (png_ptr == NULL)
-      return;
-
-   png_debug(1, "in png_write_image");
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   /* Initialize interlace handling.  If image is not interlaced,
-    * this will set pass to 1
-    */
-   num_pass = png_set_interlace_handling(png_ptr);
-#else
-   num_pass = 1;
-#endif
-   /* Loop through passes */
-   for (pass = 0; pass < num_pass; pass++)
-   {
-      /* Loop through image */
-      for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
-      {
-         png_write_row(png_ptr, *rp);
-      }
-   }
-}
-
-/* Called by user to write a row of image data */
-void PNGAPI
-png_write_row(png_structp png_ptr, png_const_bytep row)
-{
-   /* 1.5.6: moved from png_struct to be a local structure: */
-   png_row_info row_info;
-
-   if (png_ptr == NULL)
-      return;
-
-   png_debug2(1, "in png_write_row (row %u, pass %d)",
-      png_ptr->row_number, png_ptr->pass);
-
-   /* Initialize transformations and other stuff if first time */
-   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
-   {
-      /* Make sure we wrote the header info */
-      if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
-         png_error(png_ptr,
-             "png_write_info was never called before png_write_row");
-
-      /* Check for transforms that have been set but were defined out */
-#if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
-      if (png_ptr->transformations & PNG_INVERT_MONO)
-         png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
-#endif
-
-#if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
-      if (png_ptr->transformations & PNG_FILLER)
-         png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
-#endif
-#if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
-    defined(PNG_READ_PACKSWAP_SUPPORTED)
-      if (png_ptr->transformations & PNG_PACKSWAP)
-         png_warning(png_ptr,
-             "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
-#endif
-
-#if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
-      if (png_ptr->transformations & PNG_PACK)
-         png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
-#endif
-
-#if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
-      if (png_ptr->transformations & PNG_SHIFT)
-         png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
-#endif
-
-#if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
-      if (png_ptr->transformations & PNG_BGR)
-         png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
-#endif
-
-#if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
-      if (png_ptr->transformations & PNG_SWAP_BYTES)
-         png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
-#endif
-
-      png_write_start_row(png_ptr);
-   }
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   /* If interlaced and not interested in row, return */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
-   {
-      switch (png_ptr->pass)
-      {
-         case 0:
-            if (png_ptr->row_number & 0x07)
-            {
-               png_write_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 1:
-            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
-            {
-               png_write_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 2:
-            if ((png_ptr->row_number & 0x07) != 4)
-            {
-               png_write_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 3:
-            if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)
-            {
-               png_write_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 4:
-            if ((png_ptr->row_number & 0x03) != 2)
-            {
-               png_write_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 5:
-            if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)
-            {
-               png_write_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         case 6:
-            if (!(png_ptr->row_number & 0x01))
-            {
-               png_write_finish_row(png_ptr);
-               return;
-            }
-            break;
-
-         default: /* error: ignore it */
-            break;
-      }
-   }
-#endif
-
-   /* Set up row info for transformations */
-   row_info.color_type = png_ptr->color_type;
-   row_info.width = png_ptr->usr_width;
-   row_info.channels = png_ptr->usr_channels;
-   row_info.bit_depth = png_ptr->usr_bit_depth;
-   row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
-   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
-
-   png_debug1(3, "row_info->color_type = %d", row_info.color_type);
-   png_debug1(3, "row_info->width = %u", row_info.width);
-   png_debug1(3, "row_info->channels = %d", row_info.channels);
-   png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
-   png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
-   png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
-
-   /* Copy user's row into buffer, leaving room for filter byte. */
-   png_memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   /* Handle interlacing */
-   if (png_ptr->interlaced && png_ptr->pass < 6 &&
-       (png_ptr->transformations & PNG_INTERLACE))
-   {
-      png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
-      /* This should always get caught above, but still ... */
-      if (!(row_info.width))
-      {
-         png_write_finish_row(png_ptr);
-         return;
-      }
-   }
-#endif
-
-#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
-   /* Handle other transformations */
-   if (png_ptr->transformations)
-      png_do_write_transformations(png_ptr, &row_info);
-#endif
-
-   /* At this point the row_info pixel depth must match the 'transformed' depth,
-    * which is also the output depth.
-    */
-   if (row_info.pixel_depth != png_ptr->pixel_depth ||
-      row_info.pixel_depth != png_ptr->transformed_pixel_depth)
-      png_error(png_ptr, "internal write transform logic error");
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-   /* Write filter_method 64 (intrapixel differencing) only if
-    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
-    * 2. Libpng did not write a PNG signature (this filter_method is only
-    *    used in PNG datastreams that are embedded in MNG datastreams) and
-    * 3. The application called png_permit_mng_features with a mask that
-    *    included PNG_FLAG_MNG_FILTER_64 and
-    * 4. The filter_method is 64 and
-    * 5. The color_type is RGB or RGBA
-    */
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
-       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
-   {
-      /* Intrapixel differencing */
-      png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
-   }
-#endif
-
-/* Added at libpng-1.5.10 */
-#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
-   /* Check for out-of-range palette index */
-   if(row_info.color_type == PNG_COLOR_TYPE_PALETTE)
-      png_do_check_palette_indexes(png_ptr, &row_info);
-#endif
-
-   /* Find a filter if necessary, filter the row and write it out. */
-   png_write_find_filter(png_ptr, &row_info);
-
-   if (png_ptr->write_row_fn != NULL)
-      (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
-}
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-/* Set the automatic flush interval or 0 to turn flushing off */
-void PNGAPI
-png_set_flush(png_structp png_ptr, int nrows)
-{
-   png_debug(1, "in png_set_flush");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
-}
-
-/* Flush the current output buffers now */
-void PNGAPI
-png_write_flush(png_structp png_ptr)
-{
-   int wrote_IDAT;
-
-   png_debug(1, "in png_write_flush");
-
-   if (png_ptr == NULL)
-      return;
-
-   /* We have already written out all of the data */
-   if (png_ptr->row_number >= png_ptr->num_rows)
-      return;
-
-   do
-   {
-      int ret;
-
-      /* Compress the data */
-      ret = deflate(&png_ptr->zstream, Z_SYNC_FLUSH);
-      wrote_IDAT = 0;
-
-      /* Check for compression errors */
-      if (ret != Z_OK)
-      {
-         if (png_ptr->zstream.msg != NULL)
-            png_error(png_ptr, png_ptr->zstream.msg);
-
-         else
-            png_error(png_ptr, "zlib error");
-      }
-
-      if (!(png_ptr->zstream.avail_out))
-      {
-         /* Write the IDAT and reset the zlib output buffer */
-         png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
-         wrote_IDAT = 1;
-      }
-   } while (wrote_IDAT == 1);
-
-   /* If there is any data left to be output, write it into a new IDAT */
-   if (png_ptr->zbuf_size != png_ptr->zstream.avail_out)
-   {
-      /* Write the IDAT and reset the zlib output buffer */
-      png_write_IDAT(png_ptr, png_ptr->zbuf,
-          png_ptr->zbuf_size - png_ptr->zstream.avail_out);
-   }
-   png_ptr->flush_rows = 0;
-   png_flush(png_ptr);
-}
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
-
-/* Free all memory used by the write */
-void PNGAPI
-png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
-{
-   png_structp png_ptr = NULL;
-   png_infop info_ptr = NULL;
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_free_ptr free_fn = NULL;
-   png_voidp mem_ptr = NULL;
-#endif
-
-   png_debug(1, "in png_destroy_write_struct");
-
-   if (png_ptr_ptr != NULL)
-      png_ptr = *png_ptr_ptr;
-
-#ifdef PNG_USER_MEM_SUPPORTED
-   if (png_ptr != NULL)
-   {
-      free_fn = png_ptr->free_fn;
-      mem_ptr = png_ptr->mem_ptr;
-   }
-#endif
-
-   if (info_ptr_ptr != NULL)
-      info_ptr = *info_ptr_ptr;
-
-   if (info_ptr != NULL)
-   {
-      if (png_ptr != NULL)
-      {
-         png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-         if (png_ptr->num_chunk_list)
-         {
-            png_free(png_ptr, png_ptr->chunk_list);
-            png_ptr->num_chunk_list = 0;
-         }
-#endif
-      }
-
-#ifdef PNG_USER_MEM_SUPPORTED
-      png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
-          (png_voidp)mem_ptr);
-#else
-      png_destroy_struct((png_voidp)info_ptr);
-#endif
-      *info_ptr_ptr = NULL;
-   }
-
-   if (png_ptr != NULL)
-   {
-      png_write_destroy(png_ptr);
-#ifdef PNG_USER_MEM_SUPPORTED
-      png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
-          (png_voidp)mem_ptr);
-#else
-      png_destroy_struct((png_voidp)png_ptr);
-#endif
-      *png_ptr_ptr = NULL;
-   }
-}
-
-
-/* Free any memory used in png_ptr struct (old method) */
-void /* PRIVATE */
-png_write_destroy(png_structp png_ptr)
-{
-#ifdef PNG_SETJMP_SUPPORTED
-   jmp_buf tmp_jmp; /* Save jump buffer */
-#endif
-   png_error_ptr error_fn;
-#ifdef PNG_WARNINGS_SUPPORTED
-   png_error_ptr warning_fn;
-#endif
-   png_voidp error_ptr;
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_free_ptr free_fn;
-#endif
-
-   png_debug(1, "in png_write_destroy");
-
-   /* Free any memory zlib uses */
-   if (png_ptr->zlib_state != PNG_ZLIB_UNINITIALIZED)
-      deflateEnd(&png_ptr->zstream);
-
-   /* Free our memory.  png_free checks NULL for us. */
-   png_free(png_ptr, png_ptr->zbuf);
-   png_free(png_ptr, png_ptr->row_buf);
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-   png_free(png_ptr, png_ptr->prev_row);
-   png_free(png_ptr, png_ptr->sub_row);
-   png_free(png_ptr, png_ptr->up_row);
-   png_free(png_ptr, png_ptr->avg_row);
-   png_free(png_ptr, png_ptr->paeth_row);
-#endif
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   /* Use this to save a little code space, it doesn't free the filter_costs */
-   png_reset_filter_heuristics(png_ptr);
-   png_free(png_ptr, png_ptr->filter_costs);
-   png_free(png_ptr, png_ptr->inv_filter_costs);
-#endif
-
-#ifdef PNG_SETJMP_SUPPORTED
-   /* Reset structure */
-   png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
-#endif
-
-   error_fn = png_ptr->error_fn;
-#ifdef PNG_WARNINGS_SUPPORTED
-   warning_fn = png_ptr->warning_fn;
-#endif
-   error_ptr = png_ptr->error_ptr;
-#ifdef PNG_USER_MEM_SUPPORTED
-   free_fn = png_ptr->free_fn;
-#endif
-
-   png_memset(png_ptr, 0, png_sizeof(png_struct));
-
-   png_ptr->error_fn = error_fn;
-#ifdef PNG_WARNINGS_SUPPORTED
-   png_ptr->warning_fn = warning_fn;
-#endif
-   png_ptr->error_ptr = error_ptr;
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_ptr->free_fn = free_fn;
-#endif
-
-#ifdef PNG_SETJMP_SUPPORTED
-   png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
-#endif
-}
-
-/* Allow the application to select one or more row filters to use. */
-void PNGAPI
-png_set_filter(png_structp png_ptr, int method, int filters)
-{
-   png_debug(1, "in png_set_filter");
-
-   if (png_ptr == NULL)
-      return;
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
-       (method == PNG_INTRAPIXEL_DIFFERENCING))
-      method = PNG_FILTER_TYPE_BASE;
-
-#endif
-   if (method == PNG_FILTER_TYPE_BASE)
-   {
-      switch (filters & (PNG_ALL_FILTERS | 0x07))
-      {
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-         case 5:
-         case 6:
-         case 7: png_warning(png_ptr, "Unknown row filter for method 0");
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
-         case PNG_FILTER_VALUE_NONE:
-            png_ptr->do_filter = PNG_FILTER_NONE; break;
-
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-         case PNG_FILTER_VALUE_SUB:
-            png_ptr->do_filter = PNG_FILTER_SUB; break;
-
-         case PNG_FILTER_VALUE_UP:
-            png_ptr->do_filter = PNG_FILTER_UP; break;
-
-         case PNG_FILTER_VALUE_AVG:
-            png_ptr->do_filter = PNG_FILTER_AVG; break;
-
-         case PNG_FILTER_VALUE_PAETH:
-            png_ptr->do_filter = PNG_FILTER_PAETH; break;
-
-         default:
-            png_ptr->do_filter = (png_byte)filters; break;
-#else
-         default:
-            png_warning(png_ptr, "Unknown row filter for method 0");
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
-      }
-
-      /* If we have allocated the row_buf, this means we have already started
-       * with the image and we should have allocated all of the filter buffers
-       * that have been selected.  If prev_row isn't already allocated, then
-       * it is too late to start using the filters that need it, since we
-       * will be missing the data in the previous row.  If an application
-       * wants to start and stop using particular filters during compression,
-       * it should start out with all of the filters, and then add and
-       * remove them after the start of compression.
-       */
-      if (png_ptr->row_buf != NULL)
-      {
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-         if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
-         {
-            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
-                (png_ptr->rowbytes + 1));
-            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
-         }
-
-         if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
-         {
-            if (png_ptr->prev_row == NULL)
-            {
-               png_warning(png_ptr, "Can't add Up filter after starting");
-               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
-                   ~PNG_FILTER_UP);
-            }
-
-            else
-            {
-               png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
-                   (png_ptr->rowbytes + 1));
-               png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
-            }
-         }
-
-         if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
-         {
-            if (png_ptr->prev_row == NULL)
-            {
-               png_warning(png_ptr, "Can't add Average filter after starting");
-               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
-                   ~PNG_FILTER_AVG);
-            }
-
-            else
-            {
-               png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
-                   (png_ptr->rowbytes + 1));
-               png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
-            }
-         }
-
-         if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
-             png_ptr->paeth_row == NULL)
-         {
-            if (png_ptr->prev_row == NULL)
-            {
-               png_warning(png_ptr, "Can't add Paeth filter after starting");
-               png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
-            }
-
-            else
-            {
-               png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
-                   (png_ptr->rowbytes + 1));
-               png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
-            }
-         }
-
-         if (png_ptr->do_filter == PNG_NO_FILTERS)
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
-            png_ptr->do_filter = PNG_FILTER_NONE;
-      }
-   }
-   else
-      png_error(png_ptr, "Unknown custom filter method");
-}
-
-/* This allows us to influence the way in which libpng chooses the "best"
- * filter for the current scanline.  While the "minimum-sum-of-absolute-
- * differences metric is relatively fast and effective, there is some
- * question as to whether it can be improved upon by trying to keep the
- * filtered data going to zlib more consistent, hopefully resulting in
- * better compression.
- */
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED      /* GRR 970116 */
-/* Convenience reset API. */
-static void
-png_reset_filter_heuristics(png_structp png_ptr)
-{
-   /* Clear out any old values in the 'weights' - this must be done because if
-    * the app calls set_filter_heuristics multiple times with different
-    * 'num_weights' values we would otherwise potentially have wrong sized
-    * arrays.
-    */
-   png_ptr->num_prev_filters = 0;
-   png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;
-   if (png_ptr->prev_filters != NULL)
-   {
-      png_bytep old = png_ptr->prev_filters;
-      png_ptr->prev_filters = NULL;
-      png_free(png_ptr, old);
-   }
-   if (png_ptr->filter_weights != NULL)
-   {
-      png_uint_16p old = png_ptr->filter_weights;
-      png_ptr->filter_weights = NULL;
-      png_free(png_ptr, old);
-   }
-
-   if (png_ptr->inv_filter_weights != NULL)
-   {
-      png_uint_16p old = png_ptr->inv_filter_weights;
-      png_ptr->inv_filter_weights = NULL;
-      png_free(png_ptr, old);
-   }
-
-   /* Leave the filter_costs - this array is fixed size. */
-}
-
-static int
-png_init_filter_heuristics(png_structp png_ptr, int heuristic_method,
-   int num_weights)
-{
-   if (png_ptr == NULL)
-      return 0;
-
-   /* Clear out the arrays */
-   png_reset_filter_heuristics(png_ptr);
-
-   /* Check arguments; the 'reset' function makes the correct settings for the
-    * unweighted case, but we must handle the weight case by initializing the
-    * arrays for the caller.
-    */
-   if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-   {
-      int i;
-
-      if (num_weights > 0)
-      {
-         png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,
-             (png_uint_32)(png_sizeof(png_byte) * num_weights));
-
-         /* To make sure that the weighting starts out fairly */
-         for (i = 0; i < num_weights; i++)
-         {
-            png_ptr->prev_filters[i] = 255;
-         }
-
-         png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr,
-             (png_uint_32)(png_sizeof(png_uint_16) * num_weights));
-
-         png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr,
-             (png_uint_32)(png_sizeof(png_uint_16) * num_weights));
-
-         for (i = 0; i < num_weights; i++)
-         {
-            png_ptr->inv_filter_weights[i] =
-            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
-         }
-
-         /* Safe to set this now */
-         png_ptr->num_prev_filters = (png_byte)num_weights;
-      }
-
-      /* If, in the future, there are other filter methods, this would
-       * need to be based on png_ptr->filter.
-       */
-      if (png_ptr->filter_costs == NULL)
-      {
-         png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr,
-             (png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
-
-         png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr,
-             (png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
-      }
-
-      for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
-      {
-         png_ptr->inv_filter_costs[i] =
-         png_ptr->filter_costs[i] = PNG_COST_FACTOR;
-      }
-
-      /* All the arrays are inited, safe to set this: */
-      png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_WEIGHTED;
-
-      /* Return the 'ok' code. */
-      return 1;
-   }
-   else if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT ||
-      heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)
-   {
-      return 1;
-   }
-   else
-   {
-      png_warning(png_ptr, "Unknown filter heuristic method");
-      return 0;
-   }
-}
-
-/* Provide floating and fixed point APIs */
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-void PNGAPI
-png_set_filter_heuristics(png_structp png_ptr, int heuristic_method,
-    int num_weights, png_const_doublep filter_weights,
-    png_const_doublep filter_costs)
-{
-   png_debug(1, "in png_set_filter_heuristics");
-
-   /* The internal API allocates all the arrays and ensures that the elements of
-    * those arrays are set to the default value.
-    */
-   if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
-      return;
-
-   /* If using the weighted method copy in the weights. */
-   if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-   {
-      int i;
-      for (i = 0; i < num_weights; i++)
-      {
-         if (filter_weights[i] <= 0.0)
-         {
-            png_ptr->inv_filter_weights[i] =
-            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
-         }
-
-         else
-         {
-            png_ptr->inv_filter_weights[i] =
-                (png_uint_16)(PNG_WEIGHT_FACTOR*filter_weights[i]+.5);
-
-            png_ptr->filter_weights[i] =
-                (png_uint_16)(PNG_WEIGHT_FACTOR/filter_weights[i]+.5);
-         }
-      }
-
-      /* Here is where we set the relative costs of the different filters.  We
-       * should take the desired compression level into account when setting
-       * the costs, so that Paeth, for instance, has a high relative cost at low
-       * compression levels, while it has a lower relative cost at higher
-       * compression settings.  The filter types are in order of increasing
-       * relative cost, so it would be possible to do this with an algorithm.
-       */
-      for (i = 0; i < PNG_FILTER_VALUE_LAST; i++) if (filter_costs[i] >= 1.0)
-      {
-         png_ptr->inv_filter_costs[i] =
-             (png_uint_16)(PNG_COST_FACTOR / filter_costs[i] + .5);
-
-         png_ptr->filter_costs[i] =
-             (png_uint_16)(PNG_COST_FACTOR * filter_costs[i] + .5);
-      }
-   }
-}
-#endif /* FLOATING_POINT */
-
-#ifdef PNG_FIXED_POINT_SUPPORTED
-void PNGAPI
-png_set_filter_heuristics_fixed(png_structp png_ptr, int heuristic_method,
-    int num_weights, png_const_fixed_point_p filter_weights,
-    png_const_fixed_point_p filter_costs)
-{
-   png_debug(1, "in png_set_filter_heuristics_fixed");
-
-   /* The internal API allocates all the arrays and ensures that the elements of
-    * those arrays are set to the default value.
-    */
-   if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
-      return;
-
-   /* If using the weighted method copy in the weights. */
-   if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-   {
-      int i;
-      for (i = 0; i < num_weights; i++)
-      {
-         if (filter_weights[i] <= 0)
-         {
-            png_ptr->inv_filter_weights[i] =
-            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
-         }
-
-         else
-         {
-            png_ptr->inv_filter_weights[i] = (png_uint_16)
-               ((PNG_WEIGHT_FACTOR*filter_weights[i]+PNG_FP_HALF)/PNG_FP_1);
-
-            png_ptr->filter_weights[i] = (png_uint_16)((PNG_WEIGHT_FACTOR*
-               PNG_FP_1+(filter_weights[i]/2))/filter_weights[i]);
-         }
-      }
-
-      /* Here is where we set the relative costs of the different filters.  We
-       * should take the desired compression level into account when setting
-       * the costs, so that Paeth, for instance, has a high relative cost at low
-       * compression levels, while it has a lower relative cost at higher
-       * compression settings.  The filter types are in order of increasing
-       * relative cost, so it would be possible to do this with an algorithm.
-       */
-      for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
-         if (filter_costs[i] >= PNG_FP_1)
-      {
-         png_uint_32 tmp;
-
-         /* Use a 32 bit unsigned temporary here because otherwise the
-          * intermediate value will be a 32 bit *signed* integer (ANSI rules)
-          * and this will get the wrong answer on division.
-          */
-         tmp = PNG_COST_FACTOR*PNG_FP_1 + (filter_costs[i]/2);
-         tmp /= filter_costs[i];
-
-         png_ptr->inv_filter_costs[i] = (png_uint_16)tmp;
-
-         tmp = PNG_COST_FACTOR * filter_costs[i] + PNG_FP_HALF;
-         tmp /= PNG_FP_1;
-
-         png_ptr->filter_costs[i] = (png_uint_16)tmp;
-      }
-   }
-}
-#endif /* FIXED_POINT */
-#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
-
-void PNGAPI
-png_set_compression_level(png_structp png_ptr, int level)
-{
-   png_debug(1, "in png_set_compression_level");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_LEVEL;
-   png_ptr->zlib_level = level;
-}
-
-void PNGAPI
-png_set_compression_mem_level(png_structp png_ptr, int mem_level)
-{
-   png_debug(1, "in png_set_compression_mem_level");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL;
-   png_ptr->zlib_mem_level = mem_level;
-}
-
-void PNGAPI
-png_set_compression_strategy(png_structp png_ptr, int strategy)
-{
-   png_debug(1, "in png_set_compression_strategy");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
-   png_ptr->zlib_strategy = strategy;
-}
-
-/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
- * smaller value of window_bits if it can do so safely.
- */
-void PNGAPI
-png_set_compression_window_bits(png_structp png_ptr, int window_bits)
-{
-   if (png_ptr == NULL)
-      return;
-
-   if (window_bits > 15)
-      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
-
-   else if (window_bits < 8)
-      png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
-
-#ifndef WBITS_8_OK
-   /* Avoid libpng bug with 256-byte windows */
-   if (window_bits == 8)
-      {
-        png_warning(png_ptr, "Compression window is being reset to 512");
-        window_bits = 9;
-      }
-
-#endif
-   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS;
-   png_ptr->zlib_window_bits = window_bits;
-}
-
-void PNGAPI
-png_set_compression_method(png_structp png_ptr, int method)
-{
-   png_debug(1, "in png_set_compression_method");
-
-   if (png_ptr == NULL)
-      return;
-
-   if (method != 8)
-      png_warning(png_ptr, "Only compression method 8 is supported by PNG");
-
-   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_METHOD;
-   png_ptr->zlib_method = method;
-}
-
-/* The following were added to libpng-1.5.4 */
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
-void PNGAPI
-png_set_text_compression_level(png_structp png_ptr, int level)
-{
-   png_debug(1, "in png_set_text_compression_level");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_LEVEL;
-   png_ptr->zlib_text_level = level;
-}
-
-void PNGAPI
-png_set_text_compression_mem_level(png_structp png_ptr, int mem_level)
-{
-   png_debug(1, "in png_set_text_compression_mem_level");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL;
-   png_ptr->zlib_text_mem_level = mem_level;
-}
-
-void PNGAPI
-png_set_text_compression_strategy(png_structp png_ptr, int strategy)
-{
-   png_debug(1, "in png_set_text_compression_strategy");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_STRATEGY;
-   png_ptr->zlib_text_strategy = strategy;
-}
-
-/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
- * smaller value of window_bits if it can do so safely.
- */
-void PNGAPI
-png_set_text_compression_window_bits(png_structp png_ptr, int window_bits)
-{
-   if (png_ptr == NULL)
-      return;
-
-   if (window_bits > 15)
-      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
-
-   else if (window_bits < 8)
-      png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
-
-#ifndef WBITS_8_OK
-   /* Avoid libpng bug with 256-byte windows */
-   if (window_bits == 8)
-      {
-        png_warning(png_ptr, "Text compression window is being reset to 512");
-        window_bits = 9;
-      }
-
-#endif
-   png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS;
-   png_ptr->zlib_text_window_bits = window_bits;
-}
-
-void PNGAPI
-png_set_text_compression_method(png_structp png_ptr, int method)
-{
-   png_debug(1, "in png_set_text_compression_method");
-
-   if (png_ptr == NULL)
-      return;
-
-   if (method != 8)
-      png_warning(png_ptr, "Only compression method 8 is supported by PNG");
-
-   png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_METHOD;
-   png_ptr->zlib_text_method = method;
-}
-#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
-/* end of API added to libpng-1.5.4 */
-
-void PNGAPI
-png_set_write_status_fn(png_structp png_ptr, png_write_status_ptr write_row_fn)
-{
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->write_row_fn = write_row_fn;
-}
-
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-void PNGAPI
-png_set_write_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
-    write_user_transform_fn)
-{
-   png_debug(1, "in png_set_write_user_transform_fn");
-
-   if (png_ptr == NULL)
-      return;
-
-   png_ptr->transformations |= PNG_USER_TRANSFORM;
-   png_ptr->write_user_transform_fn = write_user_transform_fn;
-}
-#endif
-
-
-#ifdef PNG_INFO_IMAGE_SUPPORTED
-void PNGAPI
-png_write_png(png_structp png_ptr, png_infop info_ptr,
-    int transforms, voidp params)
-{
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   /* Write the file header information. */
-   png_write_info(png_ptr, info_ptr);
-
-   /* ------ these transformations don't touch the info structure ------- */
-
-#ifdef PNG_WRITE_INVERT_SUPPORTED
-   /* Invert monochrome pixels */
-   if (transforms & PNG_TRANSFORM_INVERT_MONO)
-      png_set_invert_mono(png_ptr);
-#endif
-
-#ifdef PNG_WRITE_SHIFT_SUPPORTED
-   /* Shift the pixels up to a legal bit depth and fill in
-    * as appropriate to correctly scale the image.
-    */
-   if ((transforms & PNG_TRANSFORM_SHIFT)
-       && (info_ptr->valid & PNG_INFO_sBIT))
-      png_set_shift(png_ptr, &info_ptr->sig_bit);
-#endif
-
-#ifdef PNG_WRITE_PACK_SUPPORTED
-   /* Pack pixels into bytes */
-   if (transforms & PNG_TRANSFORM_PACKING)
-       png_set_packing(png_ptr);
-#endif
-
-#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-   /* Swap location of alpha bytes from ARGB to RGBA */
-   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
-      png_set_swap_alpha(png_ptr);
-#endif
-
-#ifdef PNG_WRITE_FILLER_SUPPORTED
-   /* Pack XRGB/RGBX/ARGB/RGBA into RGB (4 channels -> 3 channels) */
-   if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
-      png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
-
-   else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
-      png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
-#endif
-
-#ifdef PNG_WRITE_BGR_SUPPORTED
-   /* Flip BGR pixels to RGB */
-   if (transforms & PNG_TRANSFORM_BGR)
-      png_set_bgr(png_ptr);
-#endif
-
-#ifdef PNG_WRITE_SWAP_SUPPORTED
-   /* Swap bytes of 16-bit files to most significant byte first */
-   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
-      png_set_swap(png_ptr);
-#endif
-
-#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
-   /* Swap bits of 1, 2, 4 bit packed pixel formats */
-   if (transforms & PNG_TRANSFORM_PACKSWAP)
-      png_set_packswap(png_ptr);
-#endif
-
-#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-   /* Invert the alpha channel from opacity to transparency */
-   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
-      png_set_invert_alpha(png_ptr);
-#endif
-
-   /* ----------------------- end of transformations ------------------- */
-
-   /* Write the bits */
-   if (info_ptr->valid & PNG_INFO_IDAT)
-       png_write_image(png_ptr, info_ptr->row_pointers);
-
-   /* It is REQUIRED to call this to finish writing the rest of the file */
-   png_write_end(png_ptr, info_ptr);
-
-   PNG_UNUSED(transforms)   /* Quiet compiler warnings */
-   PNG_UNUSED(params)
-}
-#endif
-#endif /* PNG_WRITE_SUPPORTED */
diff --git a/extern/libpng/include/pngwtran.c b/extern/libpng/include/pngwtran.c
deleted file mode 100644
index 96608efcb4..0000000000
--- a/extern/libpng/include/pngwtran.c
+++ /dev/null
@@ -1,633 +0,0 @@
-
-/* pngwtran.c - transforms the data in a row for PNG writers
- *
- * Last changed in libpng 1.5.6 [November 3, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_WRITE_SUPPORTED
-
-#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
-/* Transform the data according to the user's wishes.  The order of
- * transformations is significant.
- */
-void /* PRIVATE */
-png_do_write_transformations(png_structp png_ptr, png_row_infop row_info)
-{
-   png_debug(1, "in png_do_write_transformations");
-
-   if (png_ptr == NULL)
-      return;
-
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
-      if (png_ptr->write_user_transform_fn != NULL)
-         (*(png_ptr->write_user_transform_fn)) /* User write transform
-                                                 function */
-             (png_ptr,  /* png_ptr */
-             row_info,  /* row_info: */
-                /*  png_uint_32 width;       width of row */
-                /*  png_size_t rowbytes;     number of bytes in row */
-                /*  png_byte color_type;     color type of pixels */
-                /*  png_byte bit_depth;      bit depth of samples */
-                /*  png_byte channels;       number of channels (1-4) */
-                /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
-             png_ptr->row_buf + 1);      /* start of pixel data for row */
-#endif
-
-#ifdef PNG_WRITE_FILLER_SUPPORTED
-   if (png_ptr->transformations & PNG_FILLER)
-      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
-         !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
-#endif
-
-#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_PACKSWAP)
-      png_do_packswap(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
-      png_do_pack(row_info, png_ptr->row_buf + 1,
-          (png_uint_32)png_ptr->bit_depth);
-#endif
-
-#ifdef PNG_WRITE_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
-      png_do_swap(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
-      png_do_shift(row_info, png_ptr->row_buf + 1,
-          &(png_ptr->shift));
-#endif
-
-#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_ALPHA)
-      png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_ALPHA)
-      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
-      png_do_bgr(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
-      png_do_invert(row_info, png_ptr->row_buf + 1);
-#endif
-}
-
-#ifdef PNG_WRITE_PACK_SUPPORTED
-/* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
- * row_info bit depth should be 8 (one pixel per byte).  The channels
- * should be 1 (this only happens on grayscale and paletted images).
- */
-void /* PRIVATE */
-png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
-{
-   png_debug(1, "in png_do_pack");
-
-   if (row_info->bit_depth == 8 &&
-      row_info->channels == 1)
-   {
-      switch ((int)bit_depth)
-      {
-         case 1:
-         {
-            png_bytep sp, dp;
-            int mask, v;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            sp = row;
-            dp = row;
-            mask = 0x80;
-            v = 0;
-
-            for (i = 0; i < row_width; i++)
-            {
-               if (*sp != 0)
-                  v |= mask;
-
-               sp++;
-
-               if (mask > 1)
-                  mask >>= 1;
-
-               else
-               {
-                  mask = 0x80;
-                  *dp = (png_byte)v;
-                  dp++;
-                  v = 0;
-               }
-            }
-
-            if (mask != 0x80)
-               *dp = (png_byte)v;
-
-            break;
-         }
-
-         case 2:
-         {
-            png_bytep sp, dp;
-            int shift, v;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            sp = row;
-            dp = row;
-            shift = 6;
-            v = 0;
-
-            for (i = 0; i < row_width; i++)
-            {
-               png_byte value;
-
-               value = (png_byte)(*sp & 0x03);
-               v |= (value << shift);
-
-               if (shift == 0)
-               {
-                  shift = 6;
-                  *dp = (png_byte)v;
-                  dp++;
-                  v = 0;
-               }
-
-               else
-                  shift -= 2;
-
-               sp++;
-            }
-
-            if (shift != 6)
-               *dp = (png_byte)v;
-
-            break;
-         }
-
-         case 4:
-         {
-            png_bytep sp, dp;
-            int shift, v;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            sp = row;
-            dp = row;
-            shift = 4;
-            v = 0;
-
-            for (i = 0; i < row_width; i++)
-            {
-               png_byte value;
-
-               value = (png_byte)(*sp & 0x0f);
-               v |= (value << shift);
-
-               if (shift == 0)
-               {
-                  shift = 4;
-                  *dp = (png_byte)v;
-                  dp++;
-                  v = 0;
-               }
-
-               else
-                  shift -= 4;
-
-               sp++;
-            }
-
-            if (shift != 4)
-               *dp = (png_byte)v;
-
-            break;
-         }
-
-         default:
-            break;
-      }
-
-      row_info->bit_depth = (png_byte)bit_depth;
-      row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
-          row_info->width);
-   }
-}
-#endif
-
-#ifdef PNG_WRITE_SHIFT_SUPPORTED
-/* Shift pixel values to take advantage of whole range.  Pass the
- * true number of bits in bit_depth.  The row should be packed
- * according to row_info->bit_depth.  Thus, if you had a row of
- * bit depth 4, but the pixels only had values from 0 to 7, you
- * would pass 3 as bit_depth, and this routine would translate the
- * data to 0 to 15.
- */
-void /* PRIVATE */
-png_do_shift(png_row_infop row_info, png_bytep row,
-    png_const_color_8p bit_depth)
-{
-   png_debug(1, "in png_do_shift");
-
-   if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
-   {
-      int shift_start[4], shift_dec[4];
-      int channels = 0;
-
-      if (row_info->color_type & PNG_COLOR_MASK_COLOR)
-      {
-         shift_start[channels] = row_info->bit_depth - bit_depth->red;
-         shift_dec[channels] = bit_depth->red;
-         channels++;
-
-         shift_start[channels] = row_info->bit_depth - bit_depth->green;
-         shift_dec[channels] = bit_depth->green;
-         channels++;
-
-         shift_start[channels] = row_info->bit_depth - bit_depth->blue;
-         shift_dec[channels] = bit_depth->blue;
-         channels++;
-      }
-
-      else
-      {
-         shift_start[channels] = row_info->bit_depth - bit_depth->gray;
-         shift_dec[channels] = bit_depth->gray;
-         channels++;
-      }
-
-      if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
-      {
-         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
-         shift_dec[channels] = bit_depth->alpha;
-         channels++;
-      }
-
-      /* With low row depths, could only be grayscale, so one channel */
-      if (row_info->bit_depth < 8)
-      {
-         png_bytep bp = row;
-         png_size_t i;
-         png_byte mask;
-         png_size_t row_bytes = row_info->rowbytes;
-
-         if (bit_depth->gray == 1 && row_info->bit_depth == 2)
-            mask = 0x55;
-
-         else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
-            mask = 0x11;
-
-         else
-            mask = 0xff;
-
-         for (i = 0; i < row_bytes; i++, bp++)
-         {
-            png_uint_16 v;
-            int j;
-
-            v = *bp;
-            *bp = 0;
-
-            for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
-            {
-               if (j > 0)
-                  *bp |= (png_byte)((v << j) & 0xff);
-
-               else
-                  *bp |= (png_byte)((v >> (-j)) & mask);
-            }
-         }
-      }
-
-      else if (row_info->bit_depth == 8)
-      {
-         png_bytep bp = row;
-         png_uint_32 i;
-         png_uint_32 istop = channels * row_info->width;
-
-         for (i = 0; i < istop; i++, bp++)
-         {
-
-            png_uint_16 v;
-            int j;
-            int c = (int)(i%channels);
-
-            v = *bp;
-            *bp = 0;
-
-            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
-            {
-               if (j > 0)
-                  *bp |= (png_byte)((v << j) & 0xff);
-
-               else
-                  *bp |= (png_byte)((v >> (-j)) & 0xff);
-            }
-         }
-      }
-
-      else
-      {
-         png_bytep bp;
-         png_uint_32 i;
-         png_uint_32 istop = channels * row_info->width;
-
-         for (bp = row, i = 0; i < istop; i++)
-         {
-            int c = (int)(i%channels);
-            png_uint_16 value, v;
-            int j;
-
-            v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1));
-            value = 0;
-
-            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
-            {
-               if (j > 0)
-                  value |= (png_uint_16)((v << j) & (png_uint_16)0xffff);
-
-               else
-                  value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
-            }
-            *bp++ = (png_byte)(value >> 8);
-            *bp++ = (png_byte)(value & 0xff);
-         }
-      }
-   }
-}
-#endif
-
-#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-void /* PRIVATE */
-png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_write_swap_alpha");
-
-   {
-      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This converts from ARGB to RGBA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               png_byte save = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = save;
-            }
-         }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         else
-         {
-            /* This converts from AARRGGBB to RRGGBBAA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               png_byte save[2];
-               save[0] = *(sp++);
-               save[1] = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = save[0];
-               *(dp++) = save[1];
-            }
-         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-      }
-
-      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This converts from AG to GA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               png_byte save = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = save;
-            }
-         }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         else
-         {
-            /* This converts from AAGG to GGAA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               png_byte save[2];
-               save[0] = *(sp++);
-               save[1] = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = save[0];
-               *(dp++) = save[1];
-            }
-         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-      }
-   }
-}
-#endif
-
-#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-void /* PRIVATE */
-png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_write_invert_alpha");
-
-   {
-      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This inverts the alpha channel in RGBA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               /* Does nothing
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               */
-               sp+=3; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
-            }
-         }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         else
-         {
-            /* This inverts the alpha channel in RRGGBBAA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               /* Does nothing
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               */
-               sp+=6; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
-               *(dp++) = (png_byte)(255 - *(sp++));
-            }
-         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-      }
-
-      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-      {
-         if (row_info->bit_depth == 8)
-         {
-            /* This inverts the alpha channel in GA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               *(dp++) = *(sp++);
-               *(dp++) = (png_byte)(255 - *(sp++));
-            }
-         }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         else
-         {
-            /* This inverts the alpha channel in GGAA */
-            png_bytep sp, dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            for (i = 0, sp = dp = row; i < row_width; i++)
-            {
-               /* Does nothing
-               *(dp++) = *(sp++);
-               *(dp++) = *(sp++);
-               */
-               sp+=2; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
-               *(dp++) = (png_byte)(255 - *(sp++));
-            }
-         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-      }
-   }
-}
-#endif
-#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
-
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-/* Undoes intrapixel differencing  */
-void /* PRIVATE */
-png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
-{
-   png_debug(1, "in png_do_write_intrapixel");
-
-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
-   {
-      int bytes_per_pixel;
-      png_uint_32 row_width = row_info->width;
-      if (row_info->bit_depth == 8)
-      {
-         png_bytep rp;
-         png_uint_32 i;
-
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 3;
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 4;
-
-         else
-            return;
-
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            *(rp)     = (png_byte)((*rp       - *(rp + 1)) & 0xff);
-            *(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff);
-         }
-      }
-
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-      else if (row_info->bit_depth == 16)
-      {
-         png_bytep rp;
-         png_uint_32 i;
-
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 6;
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 8;
-
-         else
-            return;
-
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
-            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
-            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
-            png_uint_32 red  = (png_uint_32)((s0 - s1) & 0xffffL);
-            png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
-            *(rp    ) = (png_byte)((red >> 8) & 0xff);
-            *(rp + 1) = (png_byte)(red & 0xff);
-            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
-            *(rp + 5) = (png_byte)(blue & 0xff);
-         }
-      }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-   }
-}
-#endif /* PNG_MNG_FEATURES_SUPPORTED */
-#endif /* PNG_WRITE_SUPPORTED */
diff --git a/extern/libpng/include/pngwutil.c b/extern/libpng/include/pngwutil.c
deleted file mode 100644
index b49704f1a5..0000000000
--- a/extern/libpng/include/pngwutil.c
+++ /dev/null
@@ -1,3179 +0,0 @@
-
-/* pngwutil.c - utilities to write a PNG file
- *
- * Last changed in libpng 1.5.10 [March 8, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_WRITE_SUPPORTED
-
-#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
-/* Place a 32-bit number into a buffer in PNG byte order.  We work
- * with unsigned numbers for convenience, although one supported
- * ancillary chunk uses signed (two's complement) numbers.
- */
-void PNGAPI
-png_save_uint_32(png_bytep buf, png_uint_32 i)
-{
-   buf[0] = (png_byte)((i >> 24) & 0xff);
-   buf[1] = (png_byte)((i >> 16) & 0xff);
-   buf[2] = (png_byte)((i >> 8) & 0xff);
-   buf[3] = (png_byte)(i & 0xff);
-}
-
-#ifdef PNG_SAVE_INT_32_SUPPORTED
-/* The png_save_int_32 function assumes integers are stored in two's
- * complement format.  If this isn't the case, then this routine needs to
- * be modified to write data in two's complement format.  Note that,
- * the following works correctly even if png_int_32 has more than 32 bits
- * (compare the more complex code required on read for sign extention.)
- */
-void PNGAPI
-png_save_int_32(png_bytep buf, png_int_32 i)
-{
-   buf[0] = (png_byte)((i >> 24) & 0xff);
-   buf[1] = (png_byte)((i >> 16) & 0xff);
-   buf[2] = (png_byte)((i >> 8) & 0xff);
-   buf[3] = (png_byte)(i & 0xff);
-}
-#endif
-
-/* Place a 16-bit number into a buffer in PNG byte order.
- * The parameter is declared unsigned int, not png_uint_16,
- * just to avoid potential problems on pre-ANSI C compilers.
- */
-void PNGAPI
-png_save_uint_16(png_bytep buf, unsigned int i)
-{
-   buf[0] = (png_byte)((i >> 8) & 0xff);
-   buf[1] = (png_byte)(i & 0xff);
-}
-#endif
-
-/* Simple function to write the signature.  If we have already written
- * the magic bytes of the signature, or more likely, the PNG stream is
- * being embedded into another stream and doesn't need its own signature,
- * we should call png_set_sig_bytes() to tell libpng how many of the
- * bytes have already been written.
- */
-void PNGAPI
-png_write_sig(png_structp png_ptr)
-{
-   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   /* Inform the I/O callback that the signature is being written */
-   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;
-#endif
-
-   /* Write the rest of the 8 byte signature */
-   png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
-      (png_size_t)(8 - png_ptr->sig_bytes));
-
-   if (png_ptr->sig_bytes < 3)
-      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
-}
-
-/* Write the start of a PNG chunk.  The type is the chunk type.
- * The total_length is the sum of the lengths of all the data you will be
- * passing in png_write_chunk_data().
- */
-static void
-png_write_chunk_header(png_structp png_ptr, png_uint_32 chunk_name,
-    png_uint_32 length)
-{
-   png_byte buf[8];
-
-#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
-   PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
-   png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
-#endif
-
-   if (png_ptr == NULL)
-      return;
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   /* Inform the I/O callback that the chunk header is being written.
-    * PNG_IO_CHUNK_HDR requires a single I/O call.
-    */
-   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;
-#endif
-
-   /* Write the length and the chunk name */
-   png_save_uint_32(buf, length);
-   png_save_uint_32(buf + 4, chunk_name);
-   png_write_data(png_ptr, buf, 8);
-
-   /* Put the chunk name into png_ptr->chunk_name */
-   png_ptr->chunk_name = chunk_name;
-
-   /* Reset the crc and run it over the chunk name */
-   png_reset_crc(png_ptr);
-
-   png_calculate_crc(png_ptr, buf + 4, 4);
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   /* Inform the I/O callback that chunk data will (possibly) be written.
-    * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
-    */
-   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
-#endif
-}
-
-void PNGAPI
-png_write_chunk_start(png_structp png_ptr, png_const_bytep chunk_string,
-    png_uint_32 length)
-{
-   png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
-}
-
-/* Write the data of a PNG chunk started with png_write_chunk_header().
- * Note that multiple calls to this function are allowed, and that the
- * sum of the lengths from these calls *must* add up to the total_length
- * given to png_write_chunk_header().
- */
-void PNGAPI
-png_write_chunk_data(png_structp png_ptr, png_const_bytep data,
-    png_size_t length)
-{
-   /* Write the data, and run the CRC over it */
-   if (png_ptr == NULL)
-      return;
-
-   if (data != NULL && length > 0)
-   {
-      png_write_data(png_ptr, data, length);
-
-      /* Update the CRC after writing the data,
-       * in case that the user I/O routine alters it.
-       */
-      png_calculate_crc(png_ptr, data, length);
-   }
-}
-
-/* Finish a chunk started with png_write_chunk_header(). */
-void PNGAPI
-png_write_chunk_end(png_structp png_ptr)
-{
-   png_byte buf[4];
-
-   if (png_ptr == NULL) return;
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   /* Inform the I/O callback that the chunk CRC is being written.
-    * PNG_IO_CHUNK_CRC requires a single I/O function call.
-    */
-   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
-#endif
-
-   /* Write the crc in a single operation */
-   png_save_uint_32(buf, png_ptr->crc);
-
-   png_write_data(png_ptr, buf, (png_size_t)4);
-}
-
-/* Write a PNG chunk all at once.  The type is an array of ASCII characters
- * representing the chunk name.  The array must be at least 4 bytes in
- * length, and does not need to be null terminated.  To be safe, pass the
- * pre-defined chunk names here, and if you need a new one, define it
- * where the others are defined.  The length is the length of the data.
- * All the data must be present.  If that is not possible, use the
- * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
- * functions instead.
- */
-static void
-png_write_complete_chunk(png_structp png_ptr, png_uint_32 chunk_name,
-   png_const_bytep data, png_size_t length)
-{
-   if (png_ptr == NULL)
-      return;
-
-   /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
-   if (length > PNG_UINT_32_MAX)
-      png_error(png_ptr, "length exceeds PNG maxima");
-
-   png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
-   png_write_chunk_data(png_ptr, data, length);
-   png_write_chunk_end(png_ptr);
-}
-
-/* This is the API that calls the internal function above. */
-void PNGAPI
-png_write_chunk(png_structp png_ptr, png_const_bytep chunk_string,
-   png_const_bytep data, png_size_t length)
-{
-   png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
-      length);
-}
-
-/* Initialize the compressor for the appropriate type of compression. */
-static void
-png_zlib_claim(png_structp png_ptr, png_uint_32 state)
-{
-   if (!(png_ptr->zlib_state & PNG_ZLIB_IN_USE))
-   {
-      /* If already initialized for 'state' do not re-init. */
-      if (png_ptr->zlib_state != state)
-      {
-         int ret = Z_OK;
-         png_const_charp who = "-";
-
-         /* If actually initialized for another state do a deflateEnd. */
-         if (png_ptr->zlib_state != PNG_ZLIB_UNINITIALIZED)
-         {
-            ret = deflateEnd(&png_ptr->zstream);
-            who = "end";
-            png_ptr->zlib_state = PNG_ZLIB_UNINITIALIZED;
-         }
-
-         /* zlib itself detects an incomplete state on deflateEnd */
-         if (ret == Z_OK) switch (state)
-         {
-#           ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
-               case PNG_ZLIB_FOR_TEXT:
-                  ret = deflateInit2(&png_ptr->zstream,
-                     png_ptr->zlib_text_level, png_ptr->zlib_text_method,
-                     png_ptr->zlib_text_window_bits,
-                     png_ptr->zlib_text_mem_level, png_ptr->zlib_text_strategy);
-                  who = "text";
-                  break;
-#           endif
-
-            case PNG_ZLIB_FOR_IDAT:
-               ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
-                   png_ptr->zlib_method, png_ptr->zlib_window_bits,
-                   png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
-               who = "IDAT";
-               break;
-
-            default:
-               png_error(png_ptr, "invalid zlib state");
-         }
-
-         if (ret == Z_OK)
-            png_ptr->zlib_state = state;
-
-         else /* an error in deflateEnd or deflateInit2 */
-         {
-            size_t pos = 0;
-            char msg[64];
-
-            pos = png_safecat(msg, sizeof msg, pos,
-               "zlib failed to initialize compressor (");
-            pos = png_safecat(msg, sizeof msg, pos, who);
-
-            switch (ret)
-            {
-               case Z_VERSION_ERROR:
-                  pos = png_safecat(msg, sizeof msg, pos, ") version error");
-                  break;
-
-               case Z_STREAM_ERROR:
-                  pos = png_safecat(msg, sizeof msg, pos, ") stream error");
-                  break;
-
-               case Z_MEM_ERROR:
-                  pos = png_safecat(msg, sizeof msg, pos, ") memory error");
-                  break;
-
-               default:
-                  pos = png_safecat(msg, sizeof msg, pos, ") unknown error");
-                  break;
-            }
-
-            png_error(png_ptr, msg);
-         }
-      }
-
-      /* Here on success, claim the zstream: */
-      png_ptr->zlib_state |= PNG_ZLIB_IN_USE;
-   }
-
-   else
-      png_error(png_ptr, "zstream already in use (internal error)");
-}
-
-/* The opposite: release the stream.  It is also reset, this API will warn on
- * error but will not fail.
- */
-static void
-png_zlib_release(png_structp png_ptr)
-{
-   if (png_ptr->zlib_state & PNG_ZLIB_IN_USE)
-   {
-      int ret = deflateReset(&png_ptr->zstream);
-
-      png_ptr->zlib_state &= ~PNG_ZLIB_IN_USE;
-
-      if (ret != Z_OK)
-      {
-         png_const_charp err;
-         PNG_WARNING_PARAMETERS(p)
-
-         switch (ret)
-         {
-            case Z_VERSION_ERROR:
-               err = "version";
-               break;
-
-            case Z_STREAM_ERROR:
-               err = "stream";
-               break;
-
-            case Z_MEM_ERROR:
-               err = "memory";
-               break;
-
-            default:
-               err = "unknown";
-               break;
-         }
-
-         png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, ret);
-         png_warning_parameter(p, 2, err);
-
-         if (png_ptr->zstream.msg)
-            err = png_ptr->zstream.msg;
-         else
-            err = "[no zlib message]";
-
-         png_warning_parameter(p, 3, err);
-
-         png_formatted_warning(png_ptr, p,
-            "zlib failed to reset compressor: @1(@2): @3");
-      }
-   }
-
-   else
-      png_warning(png_ptr, "zstream not in use (internal error)");
-}
-
-#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
-/* This pair of functions encapsulates the operation of (a) compressing a
- * text string, and (b) issuing it later as a series of chunk data writes.
- * The compression_state structure is shared context for these functions
- * set up by the caller in order to make the whole mess thread-safe.
- */
-
-typedef struct
-{
-   png_const_bytep input;   /* The uncompressed input data */
-   png_size_t input_len;    /* Its length */
-   int num_output_ptr;      /* Number of output pointers used */
-   int max_output_ptr;      /* Size of output_ptr */
-   png_bytep *output_ptr;   /* Array of pointers to output */
-} compression_state;
-
-/* Compress given text into storage in the png_ptr structure */
-static int /* PRIVATE */
-png_text_compress(png_structp png_ptr,
-    png_const_charp text, png_size_t text_len, int compression,
-    compression_state *comp)
-{
-   int ret;
-
-   comp->num_output_ptr = 0;
-   comp->max_output_ptr = 0;
-   comp->output_ptr = NULL;
-   comp->input = NULL;
-   comp->input_len = text_len;
-
-   /* We may just want to pass the text right through */
-   if (compression == PNG_TEXT_COMPRESSION_NONE)
-   {
-      comp->input = (png_const_bytep)text;
-      return((int)text_len);
-   }
-
-   if (compression >= PNG_TEXT_COMPRESSION_LAST)
-   {
-      PNG_WARNING_PARAMETERS(p)
-
-      png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d,
-         compression);
-      png_formatted_warning(png_ptr, p, "Unknown compression type @1");
-   }
-
-   /* We can't write the chunk until we find out how much data we have,
-    * which means we need to run the compressor first and save the
-    * output.  This shouldn't be a problem, as the vast majority of
-    * comments should be reasonable, but we will set up an array of
-    * malloc'd pointers to be sure.
-    *
-    * If we knew the application was well behaved, we could simplify this
-    * greatly by assuming we can always malloc an output buffer large
-    * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
-    * and malloc this directly.  The only time this would be a bad idea is
-    * if we can't malloc more than 64K and we have 64K of random input
-    * data, or if the input string is incredibly large (although this
-    * wouldn't cause a failure, just a slowdown due to swapping).
-    */
-   png_zlib_claim(png_ptr, PNG_ZLIB_FOR_TEXT);
-
-   /* Set up the compression buffers */
-   /* TODO: the following cast hides a potential overflow problem. */
-   png_ptr->zstream.avail_in = (uInt)text_len;
-
-   /* NOTE: assume zlib doesn't overwrite the input */
-   png_ptr->zstream.next_in = (Bytef *)text;
-   png_ptr->zstream.avail_out = png_ptr->zbuf_size;
-   png_ptr->zstream.next_out = png_ptr->zbuf;
-
-   /* This is the same compression loop as in png_write_row() */
-   do
-   {
-      /* Compress the data */
-      ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
-
-      if (ret != Z_OK)
-      {
-         /* Error */
-         if (png_ptr->zstream.msg != NULL)
-            png_error(png_ptr, png_ptr->zstream.msg);
-
-         else
-            png_error(png_ptr, "zlib error");
-      }
-
-      /* Check to see if we need more room */
-      if (!(png_ptr->zstream.avail_out))
-      {
-         /* Make sure the output array has room */
-         if (comp->num_output_ptr >= comp->max_output_ptr)
-         {
-            int old_max;
-
-            old_max = comp->max_output_ptr;
-            comp->max_output_ptr = comp->num_output_ptr + 4;
-            if (comp->output_ptr != NULL)
-            {
-               png_bytepp old_ptr;
-
-               old_ptr = comp->output_ptr;
-
-               comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
-                   (png_alloc_size_t)
-                   (comp->max_output_ptr * png_sizeof(png_charpp)));
-
-               png_memcpy(comp->output_ptr, old_ptr, old_max
-                   * png_sizeof(png_charp));
-
-               png_free(png_ptr, old_ptr);
-            }
-            else
-               comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
-                   (png_alloc_size_t)
-                   (comp->max_output_ptr * png_sizeof(png_charp)));
-         }
-
-         /* Save the data */
-         comp->output_ptr[comp->num_output_ptr] =
-             (png_bytep)png_malloc(png_ptr,
-             (png_alloc_size_t)png_ptr->zbuf_size);
-
-         png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
-             png_ptr->zbuf_size);
-
-         comp->num_output_ptr++;
-
-         /* and reset the buffer */
-         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-         png_ptr->zstream.next_out = png_ptr->zbuf;
-      }
-   /* Continue until we don't have any more to compress */
-   } while (png_ptr->zstream.avail_in);
-
-   /* Finish the compression */
-   do
-   {
-      /* Tell zlib we are finished */
-      ret = deflate(&png_ptr->zstream, Z_FINISH);
-
-      if (ret == Z_OK)
-      {
-         /* Check to see if we need more room */
-         if (!(png_ptr->zstream.avail_out))
-         {
-            /* Check to make sure our output array has room */
-            if (comp->num_output_ptr >= comp->max_output_ptr)
-            {
-               int old_max;
-
-               old_max = comp->max_output_ptr;
-               comp->max_output_ptr = comp->num_output_ptr + 4;
-               if (comp->output_ptr != NULL)
-               {
-                  png_bytepp old_ptr;
-
-                  old_ptr = comp->output_ptr;
-
-                  /* This could be optimized to realloc() */
-                  comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
-                      (png_alloc_size_t)(comp->max_output_ptr *
-                      png_sizeof(png_charp)));
-
-                  png_memcpy(comp->output_ptr, old_ptr,
-                      old_max * png_sizeof(png_charp));
-
-                  png_free(png_ptr, old_ptr);
-               }
-
-               else
-                  comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
-                      (png_alloc_size_t)(comp->max_output_ptr *
-                      png_sizeof(png_charp)));
-            }
-
-            /* Save the data */
-            comp->output_ptr[comp->num_output_ptr] =
-                (png_bytep)png_malloc(png_ptr,
-                (png_alloc_size_t)png_ptr->zbuf_size);
-
-            png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
-                png_ptr->zbuf_size);
-
-            comp->num_output_ptr++;
-
-            /* and reset the buffer pointers */
-            png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-            png_ptr->zstream.next_out = png_ptr->zbuf;
-         }
-      }
-      else if (ret != Z_STREAM_END)
-      {
-         /* We got an error */
-         if (png_ptr->zstream.msg != NULL)
-            png_error(png_ptr, png_ptr->zstream.msg);
-
-         else
-            png_error(png_ptr, "zlib error");
-      }
-   } while (ret != Z_STREAM_END);
-
-   /* Text length is number of buffers plus last buffer */
-   text_len = png_ptr->zbuf_size * comp->num_output_ptr;
-
-   if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
-      text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
-
-   return((int)text_len);
-}
-
-/* Ship the compressed text out via chunk writes */
-static void /* PRIVATE */
-png_write_compressed_data_out(png_structp png_ptr, compression_state *comp,
-   png_size_t data_len)
-{
-   int i;
-
-   /* Handle the no-compression case */
-   if (comp->input)
-   {
-      png_write_chunk_data(png_ptr, comp->input, data_len);
-
-      return;
-   }
-
-#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-   /* The zbuf_size test is because the code below doesn't work if zbuf_size is
-    * '1'; simply skip it to avoid memory overwrite.
-    */
-   if (data_len >= 2 && comp->input_len < 16384 && png_ptr->zbuf_size > 1)
-   {
-      unsigned int z_cmf;  /* zlib compression method and flags */
-
-      /* Optimize the CMF field in the zlib stream.  This hack of the zlib
-       * stream is compliant to the stream specification.
-       */
-
-      if (comp->num_output_ptr)
-        z_cmf = comp->output_ptr[0][0];
-      else
-        z_cmf = png_ptr->zbuf[0];
-
-      if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
-      {
-         unsigned int z_cinfo;
-         unsigned int half_z_window_size;
-         png_size_t uncompressed_text_size = comp->input_len;
-
-         z_cinfo = z_cmf >> 4;
-         half_z_window_size = 1 << (z_cinfo + 7);
-
-         while (uncompressed_text_size <= half_z_window_size &&
-             half_z_window_size >= 256)
-         {
-            z_cinfo--;
-            half_z_window_size >>= 1;
-         }
-
-         z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
-
-         if (comp->num_output_ptr)
-         {
-
-           if (comp->output_ptr[0][0] != z_cmf)
-           {
-              int tmp;
-
-              comp->output_ptr[0][0] = (png_byte)z_cmf;
-              tmp = comp->output_ptr[0][1] & 0xe0;
-              tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
-              comp->output_ptr[0][1] = (png_byte)tmp;
-           }
-         }
-         else
-         {
-            int tmp;
-
-            png_ptr->zbuf[0] = (png_byte)z_cmf;
-            tmp = png_ptr->zbuf[1] & 0xe0;
-            tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
-            png_ptr->zbuf[1] = (png_byte)tmp;
-         }
-      }
-
-      else
-         png_error(png_ptr,
-             "Invalid zlib compression method or flags in non-IDAT chunk");
-   }
-#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
-
-   /* Write saved output buffers, if any */
-   for (i = 0; i < comp->num_output_ptr; i++)
-   {
-      png_write_chunk_data(png_ptr, comp->output_ptr[i],
-          (png_size_t)png_ptr->zbuf_size);
-
-      png_free(png_ptr, comp->output_ptr[i]);
-   }
-
-   if (comp->max_output_ptr != 0)
-      png_free(png_ptr, comp->output_ptr);
-
-   /* Write anything left in zbuf */
-   if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
-      png_write_chunk_data(png_ptr, png_ptr->zbuf,
-          (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));
-
-   /* Reset zlib for another zTXt/iTXt or image data */
-   png_zlib_release(png_ptr);
-}
-#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
-
-/* Write the IHDR chunk, and update the png_struct with the necessary
- * information.  Note that the rest of this code depends upon this
- * information being correct.
- */
-void /* PRIVATE */
-png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
-    int bit_depth, int color_type, int compression_type, int filter_type,
-    int interlace_type)
-{
-   png_byte buf[13]; /* Buffer to store the IHDR info */
-
-   png_debug(1, "in png_write_IHDR");
-
-   /* Check that we have valid input data from the application info */
-   switch (color_type)
-   {
-      case PNG_COLOR_TYPE_GRAY:
-         switch (bit_depth)
-         {
-            case 1:
-            case 2:
-            case 4:
-            case 8:
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-            case 16:
-#endif
-               png_ptr->channels = 1; break;
-
-            default:
-               png_error(png_ptr,
-                   "Invalid bit depth for grayscale image");
-         }
-         break;
-
-      case PNG_COLOR_TYPE_RGB:
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         if (bit_depth != 8 && bit_depth != 16)
-#else
-         if (bit_depth != 8)
-#endif
-            png_error(png_ptr, "Invalid bit depth for RGB image");
-
-         png_ptr->channels = 3;
-         break;
-
-      case PNG_COLOR_TYPE_PALETTE:
-         switch (bit_depth)
-         {
-            case 1:
-            case 2:
-            case 4:
-            case 8:
-               png_ptr->channels = 1;
-               break;
-
-            default:
-               png_error(png_ptr, "Invalid bit depth for paletted image");
-         }
-         break;
-
-      case PNG_COLOR_TYPE_GRAY_ALPHA:
-         if (bit_depth != 8 && bit_depth != 16)
-            png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
-
-         png_ptr->channels = 2;
-         break;
-
-      case PNG_COLOR_TYPE_RGB_ALPHA:
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         if (bit_depth != 8 && bit_depth != 16)
-#else
-         if (bit_depth != 8)
-#endif
-            png_error(png_ptr, "Invalid bit depth for RGBA image");
-
-         png_ptr->channels = 4;
-         break;
-
-      default:
-         png_error(png_ptr, "Invalid image color type specified");
-   }
-
-   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
-   {
-      png_warning(png_ptr, "Invalid compression type specified");
-      compression_type = PNG_COMPRESSION_TYPE_BASE;
-   }
-
-   /* Write filter_method 64 (intrapixel differencing) only if
-    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
-    * 2. Libpng did not write a PNG signature (this filter_method is only
-    *    used in PNG datastreams that are embedded in MNG datastreams) and
-    * 3. The application called png_permit_mng_features with a mask that
-    *    included PNG_FLAG_MNG_FILTER_64 and
-    * 4. The filter_method is 64 and
-    * 5. The color_type is RGB or RGBA
-    */
-   if (
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
-       ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
-       (color_type == PNG_COLOR_TYPE_RGB ||
-        color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
-       (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
-#endif
-       filter_type != PNG_FILTER_TYPE_BASE)
-   {
-      png_warning(png_ptr, "Invalid filter type specified");
-      filter_type = PNG_FILTER_TYPE_BASE;
-   }
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   if (interlace_type != PNG_INTERLACE_NONE &&
-       interlace_type != PNG_INTERLACE_ADAM7)
-   {
-      png_warning(png_ptr, "Invalid interlace type specified");
-      interlace_type = PNG_INTERLACE_ADAM7;
-   }
-#else
-   interlace_type=PNG_INTERLACE_NONE;
-#endif
-
-   /* Save the relevent information */
-   png_ptr->bit_depth = (png_byte)bit_depth;
-   png_ptr->color_type = (png_byte)color_type;
-   png_ptr->interlaced = (png_byte)interlace_type;
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-   png_ptr->filter_type = (png_byte)filter_type;
-#endif
-   png_ptr->compression_type = (png_byte)compression_type;
-   png_ptr->width = width;
-   png_ptr->height = height;
-
-   png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
-   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
-   /* Set the usr info, so any transformations can modify it */
-   png_ptr->usr_width = png_ptr->width;
-   png_ptr->usr_bit_depth = png_ptr->bit_depth;
-   png_ptr->usr_channels = png_ptr->channels;
-
-   /* Pack the header information into the buffer */
-   png_save_uint_32(buf, width);
-   png_save_uint_32(buf + 4, height);
-   buf[8] = (png_byte)bit_depth;
-   buf[9] = (png_byte)color_type;
-   buf[10] = (png_byte)compression_type;
-   buf[11] = (png_byte)filter_type;
-   buf[12] = (png_byte)interlace_type;
-
-   /* Write the chunk */
-   png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
-
-   /* Initialize zlib with PNG info */
-   png_ptr->zstream.zalloc = png_zalloc;
-   png_ptr->zstream.zfree = png_zfree;
-   png_ptr->zstream.opaque = (voidpf)png_ptr;
-
-   if (!(png_ptr->do_filter))
-   {
-      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
-          png_ptr->bit_depth < 8)
-         png_ptr->do_filter = PNG_FILTER_NONE;
-
-      else
-         png_ptr->do_filter = PNG_ALL_FILTERS;
-   }
-
-   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
-   {
-      if (png_ptr->do_filter != PNG_FILTER_NONE)
-         png_ptr->zlib_strategy = Z_FILTERED;
-
-      else
-         png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
-   }
-
-   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
-      png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
-
-   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
-      png_ptr->zlib_mem_level = 8;
-
-   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
-      png_ptr->zlib_window_bits = 15;
-
-   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
-      png_ptr->zlib_method = 8;
-
-#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
-   if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_STRATEGY))
-      png_ptr->zlib_text_strategy = Z_DEFAULT_STRATEGY;
-
-   if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_LEVEL))
-      png_ptr->zlib_text_level = png_ptr->zlib_level;
-
-   if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL))
-      png_ptr->zlib_text_mem_level = png_ptr->zlib_mem_level;
-
-   if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS))
-      png_ptr->zlib_text_window_bits = png_ptr->zlib_window_bits;
-
-   if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_METHOD))
-      png_ptr->zlib_text_method = png_ptr->zlib_method;
-#else
-   png_ptr->zlib_text_strategy = Z_DEFAULT_STRATEGY;
-   png_ptr->zlib_text_level = png_ptr->zlib_level;
-   png_ptr->zlib_text_mem_level = png_ptr->zlib_mem_level;
-   png_ptr->zlib_text_window_bits = png_ptr->zlib_window_bits;
-   png_ptr->zlib_text_method = png_ptr->zlib_method;
-#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
-#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
-
-   /* Record that the compressor has not yet been initialized. */
-   png_ptr->zlib_state = PNG_ZLIB_UNINITIALIZED;
-
-   png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
-}
-
-/* Write the palette.  We are careful not to trust png_color to be in the
- * correct order for PNG, so people can redefine it to any convenient
- * structure.
- */
-void /* PRIVATE */
-png_write_PLTE(png_structp png_ptr, png_const_colorp palette,
-    png_uint_32 num_pal)
-{
-   png_uint_32 i;
-   png_const_colorp pal_ptr;
-   png_byte buf[3];
-
-   png_debug(1, "in png_write_PLTE");
-
-   if ((
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-       !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
-#endif
-       num_pal == 0) || num_pal > 256)
-   {
-      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         png_error(png_ptr, "Invalid number of colors in palette");
-      }
-
-      else
-      {
-         png_warning(png_ptr, "Invalid number of colors in palette");
-         return;
-      }
-   }
-
-   if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
-   {
-      png_warning(png_ptr,
-          "Ignoring request to write a PLTE chunk in grayscale PNG");
-
-      return;
-   }
-
-   png_ptr->num_palette = (png_uint_16)num_pal;
-   png_debug1(3, "num_palette = %d", png_ptr->num_palette);
-
-   png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
-#ifdef PNG_POINTER_INDEXING_SUPPORTED
-
-   for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
-   {
-      buf[0] = pal_ptr->red;
-      buf[1] = pal_ptr->green;
-      buf[2] = pal_ptr->blue;
-      png_write_chunk_data(png_ptr, buf, (png_size_t)3);
-   }
-
-#else
-   /* This is a little slower but some buggy compilers need to do this
-    * instead
-    */
-   pal_ptr=palette;
-
-   for (i = 0; i < num_pal; i++)
-   {
-      buf[0] = pal_ptr[i].red;
-      buf[1] = pal_ptr[i].green;
-      buf[2] = pal_ptr[i].blue;
-      png_write_chunk_data(png_ptr, buf, (png_size_t)3);
-   }
-
-#endif
-   png_write_chunk_end(png_ptr);
-   png_ptr->mode |= PNG_HAVE_PLTE;
-}
-
-/* Write an IDAT chunk */
-void /* PRIVATE */
-png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
-{
-   png_debug(1, "in png_write_IDAT");
-
-#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-   if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
-       png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
-   {
-      /* Optimize the CMF field in the zlib stream.  This hack of the zlib
-       * stream is compliant to the stream specification.
-       */
-      unsigned int z_cmf = data[0];  /* zlib compression method and flags */
-
-      if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
-      {
-         /* Avoid memory underflows and multiplication overflows.
-          *
-          * The conditions below are practically always satisfied;
-          * however, they still must be checked.
-          */
-         if (length >= 2 &&
-             png_ptr->height < 16384 && png_ptr->width < 16384)
-         {
-            /* Compute the maximum possible length of the datastream */
-
-            /* Number of pixels, plus for each row a filter byte
-             * and possibly a padding byte, so increase the maximum
-             * size to account for these.
-             */
-            unsigned int z_cinfo;
-            unsigned int half_z_window_size;
-            png_uint_32 uncompressed_idat_size = png_ptr->height *
-                ((png_ptr->width *
-                png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
-
-            /* If it's interlaced, each block of 8 rows is sent as up to
-             * 14 rows, i.e., 6 additional rows, each with a filter byte
-             * and possibly a padding byte
-             */
-            if (png_ptr->interlaced)
-               uncompressed_idat_size += ((png_ptr->height + 7)/8) *
-                   (png_ptr->bit_depth < 8 ? 12 : 6);
-
-            z_cinfo = z_cmf >> 4;
-            half_z_window_size = 1 << (z_cinfo + 7);
-
-            while (uncompressed_idat_size <= half_z_window_size &&
-                half_z_window_size >= 256)
-            {
-               z_cinfo--;
-               half_z_window_size >>= 1;
-            }
-
-            z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
-
-            if (data[0] != z_cmf)
-            {
-               int tmp;
-               data[0] = (png_byte)z_cmf;
-               tmp = data[1] & 0xe0;
-               tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
-               data[1] = (png_byte)tmp;
-            }
-         }
-      }
-
-      else
-         png_error(png_ptr,
-             "Invalid zlib compression method or flags in IDAT");
-   }
-#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
-
-   png_write_complete_chunk(png_ptr, png_IDAT, data, length);
-   png_ptr->mode |= PNG_HAVE_IDAT;
-
-   /* Prior to 1.5.4 this code was replicated in every caller (except at the
-    * end, where it isn't technically necessary).  Since this function has
-    * flushed the data we can safely reset the zlib output buffer here.
-    */
-   png_ptr->zstream.next_out = png_ptr->zbuf;
-   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-}
-
-/* Write an IEND chunk */
-void /* PRIVATE */
-png_write_IEND(png_structp png_ptr)
-{
-   png_debug(1, "in png_write_IEND");
-
-   png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
-   png_ptr->mode |= PNG_HAVE_IEND;
-}
-
-#ifdef PNG_WRITE_gAMA_SUPPORTED
-/* Write a gAMA chunk */
-void /* PRIVATE */
-png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
-{
-   png_byte buf[4];
-
-   png_debug(1, "in png_write_gAMA");
-
-   /* file_gamma is saved in 1/100,000ths */
-   png_save_uint_32(buf, (png_uint_32)file_gamma);
-   png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
-}
-#endif
-
-#ifdef PNG_WRITE_sRGB_SUPPORTED
-/* Write a sRGB chunk */
-void /* PRIVATE */
-png_write_sRGB(png_structp png_ptr, int srgb_intent)
-{
-   png_byte buf[1];
-
-   png_debug(1, "in png_write_sRGB");
-
-   if (srgb_intent >= PNG_sRGB_INTENT_LAST)
-      png_warning(png_ptr,
-          "Invalid sRGB rendering intent specified");
-
-   buf[0]=(png_byte)srgb_intent;
-   png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
-}
-#endif
-
-#ifdef PNG_WRITE_iCCP_SUPPORTED
-/* Write an iCCP chunk */
-void /* PRIVATE */
-png_write_iCCP(png_structp png_ptr, png_const_charp name, int compression_type,
-    png_const_charp profile, int profile_len)
-{
-   png_size_t name_len;
-   png_charp new_name;
-   compression_state comp;
-   int embedded_profile_len = 0;
-
-   png_debug(1, "in png_write_iCCP");
-
-   comp.num_output_ptr = 0;
-   comp.max_output_ptr = 0;
-   comp.output_ptr = NULL;
-   comp.input = NULL;
-   comp.input_len = 0;
-
-   if ((name_len = png_check_keyword(png_ptr, name, &new_name)) == 0)
-      return;
-
-   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
-      png_warning(png_ptr, "Unknown compression type in iCCP chunk");
-
-   if (profile == NULL)
-      profile_len = 0;
-
-   if (profile_len > 3)
-      embedded_profile_len =
-          ((*( (png_const_bytep)profile    ))<<24) |
-          ((*( (png_const_bytep)profile + 1))<<16) |
-          ((*( (png_const_bytep)profile + 2))<< 8) |
-          ((*( (png_const_bytep)profile + 3))    );
-
-   if (embedded_profile_len < 0)
-   {
-      png_warning(png_ptr,
-          "Embedded profile length in iCCP chunk is negative");
-
-      png_free(png_ptr, new_name);
-      return;
-   }
-
-   if (profile_len < embedded_profile_len)
-   {
-      png_warning(png_ptr,
-          "Embedded profile length too large in iCCP chunk");
-
-      png_free(png_ptr, new_name);
-      return;
-   }
-
-   if (profile_len > embedded_profile_len)
-   {
-      png_warning(png_ptr,
-          "Truncating profile to actual length in iCCP chunk");
-
-      profile_len = embedded_profile_len;
-   }
-
-   if (profile_len)
-      profile_len = png_text_compress(png_ptr, profile,
-          (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);
-
-   /* Make sure we include the NULL after the name and the compression type */
-   png_write_chunk_header(png_ptr, png_iCCP,
-       (png_uint_32)(name_len + profile_len + 2));
-
-   new_name[name_len + 1] = 0x00;
-
-   png_write_chunk_data(png_ptr, (png_bytep)new_name,
-       (png_size_t)(name_len + 2));
-
-   if (profile_len)
-   {
-      png_write_compressed_data_out(png_ptr, &comp, profile_len);
-   }
-
-   png_write_chunk_end(png_ptr);
-   png_free(png_ptr, new_name);
-}
-#endif
-
-#ifdef PNG_WRITE_sPLT_SUPPORTED
-/* Write a sPLT chunk */
-void /* PRIVATE */
-png_write_sPLT(png_structp png_ptr, png_const_sPLT_tp spalette)
-{
-   png_size_t name_len;
-   png_charp new_name;
-   png_byte entrybuf[10];
-   png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);
-   png_size_t palette_size = entry_size * spalette->nentries;
-   png_sPLT_entryp ep;
-#ifndef PNG_POINTER_INDEXING_SUPPORTED
-   int i;
-#endif
-
-   png_debug(1, "in png_write_sPLT");
-
-   if ((name_len = png_check_keyword(png_ptr,spalette->name, &new_name))==0)
-      return;
-
-   /* Make sure we include the NULL after the name */
-   png_write_chunk_header(png_ptr, png_sPLT,
-       (png_uint_32)(name_len + 2 + palette_size));
-
-   png_write_chunk_data(png_ptr, (png_bytep)new_name,
-       (png_size_t)(name_len + 1));
-
-   png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1);
-
-   /* Loop through each palette entry, writing appropriately */
-#ifdef PNG_POINTER_INDEXING_SUPPORTED
-   for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
-   {
-      if (spalette->depth == 8)
-      {
-         entrybuf[0] = (png_byte)ep->red;
-         entrybuf[1] = (png_byte)ep->green;
-         entrybuf[2] = (png_byte)ep->blue;
-         entrybuf[3] = (png_byte)ep->alpha;
-         png_save_uint_16(entrybuf + 4, ep->frequency);
-      }
-
-      else
-      {
-         png_save_uint_16(entrybuf + 0, ep->red);
-         png_save_uint_16(entrybuf + 2, ep->green);
-         png_save_uint_16(entrybuf + 4, ep->blue);
-         png_save_uint_16(entrybuf + 6, ep->alpha);
-         png_save_uint_16(entrybuf + 8, ep->frequency);
-      }
-
-      png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
-   }
-#else
-   ep=spalette->entries;
-   for (i = 0; i>spalette->nentries; i++)
-   {
-      if (spalette->depth == 8)
-      {
-         entrybuf[0] = (png_byte)ep[i].red;
-         entrybuf[1] = (png_byte)ep[i].green;
-         entrybuf[2] = (png_byte)ep[i].blue;
-         entrybuf[3] = (png_byte)ep[i].alpha;
-         png_save_uint_16(entrybuf + 4, ep[i].frequency);
-      }
-
-      else
-      {
-         png_save_uint_16(entrybuf + 0, ep[i].red);
-         png_save_uint_16(entrybuf + 2, ep[i].green);
-         png_save_uint_16(entrybuf + 4, ep[i].blue);
-         png_save_uint_16(entrybuf + 6, ep[i].alpha);
-         png_save_uint_16(entrybuf + 8, ep[i].frequency);
-      }
-
-      png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
-   }
-#endif
-
-   png_write_chunk_end(png_ptr);
-   png_free(png_ptr, new_name);
-}
-#endif
-
-#ifdef PNG_WRITE_sBIT_SUPPORTED
-/* Write the sBIT chunk */
-void /* PRIVATE */
-png_write_sBIT(png_structp png_ptr, png_const_color_8p sbit, int color_type)
-{
-   png_byte buf[4];
-   png_size_t size;
-
-   png_debug(1, "in png_write_sBIT");
-
-   /* Make sure we don't depend upon the order of PNG_COLOR_8 */
-   if (color_type & PNG_COLOR_MASK_COLOR)
-   {
-      png_byte maxbits;
-
-      maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
-          png_ptr->usr_bit_depth);
-
-      if (sbit->red == 0 || sbit->red > maxbits ||
-          sbit->green == 0 || sbit->green > maxbits ||
-          sbit->blue == 0 || sbit->blue > maxbits)
-      {
-         png_warning(png_ptr, "Invalid sBIT depth specified");
-         return;
-      }
-
-      buf[0] = sbit->red;
-      buf[1] = sbit->green;
-      buf[2] = sbit->blue;
-      size = 3;
-   }
-
-   else
-   {
-      if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
-      {
-         png_warning(png_ptr, "Invalid sBIT depth specified");
-         return;
-      }
-
-      buf[0] = sbit->gray;
-      size = 1;
-   }
-
-   if (color_type & PNG_COLOR_MASK_ALPHA)
-   {
-      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
-      {
-         png_warning(png_ptr, "Invalid sBIT depth specified");
-         return;
-      }
-
-      buf[size++] = sbit->alpha;
-   }
-
-   png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
-}
-#endif
-
-#ifdef PNG_WRITE_cHRM_SUPPORTED
-/* Write the cHRM chunk */
-void /* PRIVATE */
-png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
-    png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
-    png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
-    png_fixed_point blue_y)
-{
-   png_byte buf[32];
-
-   png_debug(1, "in png_write_cHRM");
-
-   /* Each value is saved in 1/100,000ths */
-#ifdef PNG_CHECK_cHRM_SUPPORTED
-   if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y,
-       green_x, green_y, blue_x, blue_y))
-#endif
-   {
-      png_save_uint_32(buf, (png_uint_32)white_x);
-      png_save_uint_32(buf + 4, (png_uint_32)white_y);
-
-      png_save_uint_32(buf + 8, (png_uint_32)red_x);
-      png_save_uint_32(buf + 12, (png_uint_32)red_y);
-
-      png_save_uint_32(buf + 16, (png_uint_32)green_x);
-      png_save_uint_32(buf + 20, (png_uint_32)green_y);
-
-      png_save_uint_32(buf + 24, (png_uint_32)blue_x);
-      png_save_uint_32(buf + 28, (png_uint_32)blue_y);
-
-      png_write_complete_chunk(png_ptr, png_cHRM, buf, (png_size_t)32);
-   }
-}
-#endif
-
-#ifdef PNG_WRITE_tRNS_SUPPORTED
-/* Write the tRNS chunk */
-void /* PRIVATE */
-png_write_tRNS(png_structp png_ptr, png_const_bytep trans_alpha,
-    png_const_color_16p tran, int num_trans, int color_type)
-{
-   png_byte buf[6];
-
-   png_debug(1, "in png_write_tRNS");
-
-   if (color_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
-      {
-         png_warning(png_ptr, "Invalid number of transparent colors specified");
-         return;
-      }
-
-      /* Write the chunk out as it is */
-      png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha, (png_size_t)num_trans);
-   }
-
-   else if (color_type == PNG_COLOR_TYPE_GRAY)
-   {
-      /* One 16 bit value */
-      if (tran->gray >= (1 << png_ptr->bit_depth))
-      {
-         png_warning(png_ptr,
-             "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
-
-         return;
-      }
-
-      png_save_uint_16(buf, tran->gray);
-      png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
-   }
-
-   else if (color_type == PNG_COLOR_TYPE_RGB)
-   {
-      /* Three 16 bit values */
-      png_save_uint_16(buf, tran->red);
-      png_save_uint_16(buf + 2, tran->green);
-      png_save_uint_16(buf + 4, tran->blue);
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
-#else
-      if (buf[0] | buf[2] | buf[4])
-#endif
-      {
-         png_warning(png_ptr,
-           "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
-         return;
-      }
-
-      png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
-   }
-
-   else
-   {
-      png_warning(png_ptr, "Can't write tRNS with an alpha channel");
-   }
-}
-#endif
-
-#ifdef PNG_WRITE_bKGD_SUPPORTED
-/* Write the background chunk */
-void /* PRIVATE */
-png_write_bKGD(png_structp png_ptr, png_const_color_16p back, int color_type)
-{
-   png_byte buf[6];
-
-   png_debug(1, "in png_write_bKGD");
-
-   if (color_type == PNG_COLOR_TYPE_PALETTE)
-   {
-      if (
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-          (png_ptr->num_palette ||
-          (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
-#endif
-         back->index >= png_ptr->num_palette)
-      {
-         png_warning(png_ptr, "Invalid background palette index");
-         return;
-      }
-
-      buf[0] = back->index;
-      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
-   }
-
-   else if (color_type & PNG_COLOR_MASK_COLOR)
-   {
-      png_save_uint_16(buf, back->red);
-      png_save_uint_16(buf + 2, back->green);
-      png_save_uint_16(buf + 4, back->blue);
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
-#else
-      if (buf[0] | buf[2] | buf[4])
-#endif
-      {
-         png_warning(png_ptr,
-             "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
-
-         return;
-      }
-
-      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
-   }
-
-   else
-   {
-      if (back->gray >= (1 << png_ptr->bit_depth))
-      {
-         png_warning(png_ptr,
-             "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
-
-         return;
-      }
-
-      png_save_uint_16(buf, back->gray);
-      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
-   }
-}
-#endif
-
-#ifdef PNG_WRITE_hIST_SUPPORTED
-/* Write the histogram */
-void /* PRIVATE */
-png_write_hIST(png_structp png_ptr, png_const_uint_16p hist, int num_hist)
-{
-   int i;
-   png_byte buf[3];
-
-   png_debug(1, "in png_write_hIST");
-
-   if (num_hist > (int)png_ptr->num_palette)
-   {
-      png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
-          png_ptr->num_palette);
-
-      png_warning(png_ptr, "Invalid number of histogram entries specified");
-      return;
-   }
-
-   png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
-
-   for (i = 0; i < num_hist; i++)
-   {
-      png_save_uint_16(buf, hist[i]);
-      png_write_chunk_data(png_ptr, buf, (png_size_t)2);
-   }
-
-   png_write_chunk_end(png_ptr);
-}
-#endif
-
-#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
-    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
-/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
- * and if invalid, correct the keyword rather than discarding the entire
- * chunk.  The PNG 1.0 specification requires keywords 1-79 characters in
- * length, forbids leading or trailing whitespace, multiple internal spaces,
- * and the non-break space (0x80) from ISO 8859-1.  Returns keyword length.
- *
- * The new_key is allocated to hold the corrected keyword and must be freed
- * by the calling routine.  This avoids problems with trying to write to
- * static keywords without having to have duplicate copies of the strings.
- */
-png_size_t /* PRIVATE */
-png_check_keyword(png_structp png_ptr, png_const_charp key, png_charpp new_key)
-{
-   png_size_t key_len;
-   png_const_charp ikp;
-   png_charp kp, dp;
-   int kflag;
-   int kwarn=0;
-
-   png_debug(1, "in png_check_keyword");
-
-   *new_key = NULL;
-
-   if (key == NULL || (key_len = png_strlen(key)) == 0)
-   {
-      png_warning(png_ptr, "zero length keyword");
-      return ((png_size_t)0);
-   }
-
-   png_debug1(2, "Keyword to be checked is '%s'", key);
-
-   *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
-
-   if (*new_key == NULL)
-   {
-      png_warning(png_ptr, "Out of memory while procesing keyword");
-      return ((png_size_t)0);
-   }
-
-   /* Replace non-printing characters with a blank and print a warning */
-   for (ikp = key, dp = *new_key; *ikp != '\0'; ikp++, dp++)
-   {
-      if ((png_byte)*ikp < 0x20 ||
-         ((png_byte)*ikp > 0x7E && (png_byte)*ikp < 0xA1))
-      {
-         PNG_WARNING_PARAMETERS(p)
-
-         png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_02x,
-            (png_byte)*ikp);
-         png_formatted_warning(png_ptr, p, "invalid keyword character 0x@1");
-         *dp = ' ';
-      }
-
-      else
-      {
-         *dp = *ikp;
-      }
-   }
-   *dp = '\0';
-
-   /* Remove any trailing white space. */
-   kp = *new_key + key_len - 1;
-   if (*kp == ' ')
-   {
-      png_warning(png_ptr, "trailing spaces removed from keyword");
-
-      while (*kp == ' ')
-      {
-         *(kp--) = '\0';
-         key_len--;
-      }
-   }
-
-   /* Remove any leading white space. */
-   kp = *new_key;
-   if (*kp == ' ')
-   {
-      png_warning(png_ptr, "leading spaces removed from keyword");
-
-      while (*kp == ' ')
-      {
-         kp++;
-         key_len--;
-      }
-   }
-
-   png_debug1(2, "Checking for multiple internal spaces in '%s'", kp);
-
-   /* Remove multiple internal spaces. */
-   for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
-   {
-      if (*kp == ' ' && kflag == 0)
-      {
-         *(dp++) = *kp;
-         kflag = 1;
-      }
-
-      else if (*kp == ' ')
-      {
-         key_len--;
-         kwarn = 1;
-      }
-
-      else
-      {
-         *(dp++) = *kp;
-         kflag = 0;
-      }
-   }
-   *dp = '\0';
-   if (kwarn)
-      png_warning(png_ptr, "extra interior spaces removed from keyword");
-
-   if (key_len == 0)
-   {
-      png_free(png_ptr, *new_key);
-      png_warning(png_ptr, "Zero length keyword");
-   }
-
-   if (key_len > 79)
-   {
-      png_warning(png_ptr, "keyword length must be 1 - 79 characters");
-      (*new_key)[79] = '\0';
-      key_len = 79;
-   }
-
-   return (key_len);
-}
-#endif
-
-#ifdef PNG_WRITE_tEXt_SUPPORTED
-/* Write a tEXt chunk */
-void /* PRIVATE */
-png_write_tEXt(png_structp png_ptr, png_const_charp key, png_const_charp text,
-    png_size_t text_len)
-{
-   png_size_t key_len;
-   png_charp new_key;
-
-   png_debug(1, "in png_write_tEXt");
-
-   if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
-      return;
-
-   if (text == NULL || *text == '\0')
-      text_len = 0;
-
-   else
-      text_len = png_strlen(text);
-
-   /* Make sure we include the 0 after the key */
-   png_write_chunk_header(png_ptr, png_tEXt,
-       (png_uint_32)(key_len + text_len + 1));
-   /*
-    * We leave it to the application to meet PNG-1.0 requirements on the
-    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
-    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
-    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
-    */
-   png_write_chunk_data(png_ptr, (png_bytep)new_key,
-       (png_size_t)(key_len + 1));
-
-   if (text_len)
-      png_write_chunk_data(png_ptr, (png_const_bytep)text,
-          (png_size_t)text_len);
-
-   png_write_chunk_end(png_ptr);
-   png_free(png_ptr, new_key);
-}
-#endif
-
-#ifdef PNG_WRITE_zTXt_SUPPORTED
-/* Write a compressed text chunk */
-void /* PRIVATE */
-png_write_zTXt(png_structp png_ptr, png_const_charp key, png_const_charp text,
-    png_size_t text_len, int compression)
-{
-   png_size_t key_len;
-   png_byte buf;
-   png_charp new_key;
-   compression_state comp;
-
-   png_debug(1, "in png_write_zTXt");
-
-   comp.num_output_ptr = 0;
-   comp.max_output_ptr = 0;
-   comp.output_ptr = NULL;
-   comp.input = NULL;
-   comp.input_len = 0;
-
-   if ((key_len = png_check_keyword(png_ptr, key, &new_key)) == 0)
-   {
-      png_free(png_ptr, new_key);
-      return;
-   }
-
-   if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
-   {
-      png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
-      png_free(png_ptr, new_key);
-      return;
-   }
-
-   text_len = png_strlen(text);
-
-   /* Compute the compressed data; do it now for the length */
-   text_len = png_text_compress(png_ptr, text, text_len, compression,
-       &comp);
-
-   /* Write start of chunk */
-   png_write_chunk_header(png_ptr, png_zTXt,
-       (png_uint_32)(key_len+text_len + 2));
-
-   /* Write key */
-   png_write_chunk_data(png_ptr, (png_bytep)new_key,
-       (png_size_t)(key_len + 1));
-
-   png_free(png_ptr, new_key);
-
-   buf = (png_byte)compression;
-
-   /* Write compression */
-   png_write_chunk_data(png_ptr, &buf, (png_size_t)1);
-
-   /* Write the compressed data */
-   png_write_compressed_data_out(png_ptr, &comp, text_len);
-
-   /* Close the chunk */
-   png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_iTXt_SUPPORTED
-/* Write an iTXt chunk */
-void /* PRIVATE */
-png_write_iTXt(png_structp png_ptr, int compression, png_const_charp key,
-    png_const_charp lang, png_const_charp lang_key, png_const_charp text)
-{
-   png_size_t lang_len, key_len, lang_key_len, text_len;
-   png_charp new_lang;
-   png_charp new_key = NULL;
-   png_byte cbuf[2];
-   compression_state comp;
-
-   png_debug(1, "in png_write_iTXt");
-
-   comp.num_output_ptr = 0;
-   comp.max_output_ptr = 0;
-   comp.output_ptr = NULL;
-   comp.input = NULL;
-
-   if ((key_len = png_check_keyword(png_ptr, key, &new_key)) == 0)
-      return;
-
-   if ((lang_len = png_check_keyword(png_ptr, lang, &new_lang)) == 0)
-   {
-      png_warning(png_ptr, "Empty language field in iTXt chunk");
-      new_lang = NULL;
-      lang_len = 0;
-   }
-
-   if (lang_key == NULL)
-      lang_key_len = 0;
-
-   else
-      lang_key_len = png_strlen(lang_key);
-
-   if (text == NULL)
-      text_len = 0;
-
-   else
-      text_len = png_strlen(text);
-
-   /* Compute the compressed data; do it now for the length */
-   text_len = png_text_compress(png_ptr, text, text_len, compression - 2,
-       &comp);
-
-
-   /* Make sure we include the compression flag, the compression byte,
-    * and the NULs after the key, lang, and lang_key parts
-    */
-
-   png_write_chunk_header(png_ptr, png_iTXt, (png_uint_32)(
-        5 /* comp byte, comp flag, terminators for key, lang and lang_key */
-        + key_len
-        + lang_len
-        + lang_key_len
-        + text_len));
-
-   /* We leave it to the application to meet PNG-1.0 requirements on the
-    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
-    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
-    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
-    */
-   png_write_chunk_data(png_ptr, (png_bytep)new_key, (png_size_t)(key_len + 1));
-
-   /* Set the compression flag */
-   if (compression == PNG_ITXT_COMPRESSION_NONE ||
-       compression == PNG_TEXT_COMPRESSION_NONE)
-      cbuf[0] = 0;
-
-   else /* compression == PNG_ITXT_COMPRESSION_zTXt */
-      cbuf[0] = 1;
-
-   /* Set the compression method */
-   cbuf[1] = 0;
-
-   png_write_chunk_data(png_ptr, cbuf, (png_size_t)2);
-
-   cbuf[0] = 0;
-   png_write_chunk_data(png_ptr, (new_lang ? (png_const_bytep)new_lang : cbuf),
-       (png_size_t)(lang_len + 1));
-
-   png_write_chunk_data(png_ptr, (lang_key ? (png_const_bytep)lang_key : cbuf),
-       (png_size_t)(lang_key_len + 1));
-
-   png_write_compressed_data_out(png_ptr, &comp, text_len);
-
-   png_write_chunk_end(png_ptr);
-
-   png_free(png_ptr, new_key);
-   png_free(png_ptr, new_lang);
-}
-#endif
-
-#ifdef PNG_WRITE_oFFs_SUPPORTED
-/* Write the oFFs chunk */
-void /* PRIVATE */
-png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
-    int unit_type)
-{
-   png_byte buf[9];
-
-   png_debug(1, "in png_write_oFFs");
-
-   if (unit_type >= PNG_OFFSET_LAST)
-      png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
-
-   png_save_int_32(buf, x_offset);
-   png_save_int_32(buf + 4, y_offset);
-   buf[8] = (png_byte)unit_type;
-
-   png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
-}
-#endif
-#ifdef PNG_WRITE_pCAL_SUPPORTED
-/* Write the pCAL chunk (described in the PNG extensions document) */
-void /* PRIVATE */
-png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
-    png_int_32 X1, int type, int nparams, png_const_charp units,
-    png_charpp params)
-{
-   png_size_t purpose_len, units_len, total_len;
-   png_size_tp params_len;
-   png_byte buf[10];
-   png_charp new_purpose;
-   int i;
-
-   png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
-
-   if (type >= PNG_EQUATION_LAST)
-      png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
-
-   purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
-   png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
-   units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
-   png_debug1(3, "pCAL units length = %d", (int)units_len);
-   total_len = purpose_len + units_len + 10;
-
-   params_len = (png_size_tp)png_malloc(png_ptr,
-       (png_alloc_size_t)(nparams * png_sizeof(png_size_t)));
-
-   /* Find the length of each parameter, making sure we don't count the
-    * null terminator for the last parameter.
-    */
-   for (i = 0; i < nparams; i++)
-   {
-      params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
-      png_debug2(3, "pCAL parameter %d length = %lu", i,
-          (unsigned long)params_len[i]);
-      total_len += params_len[i];
-   }
-
-   png_debug1(3, "pCAL total length = %d", (int)total_len);
-   png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
-   png_write_chunk_data(png_ptr, (png_const_bytep)new_purpose, purpose_len);
-   png_save_int_32(buf, X0);
-   png_save_int_32(buf + 4, X1);
-   buf[8] = (png_byte)type;
-   buf[9] = (png_byte)nparams;
-   png_write_chunk_data(png_ptr, buf, (png_size_t)10);
-   png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);
-
-   png_free(png_ptr, new_purpose);
-
-   for (i = 0; i < nparams; i++)
-   {
-      png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
-   }
-
-   png_free(png_ptr, params_len);
-   png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_sCAL_SUPPORTED
-/* Write the sCAL chunk */
-void /* PRIVATE */
-png_write_sCAL_s(png_structp png_ptr, int unit, png_const_charp width,
-    png_const_charp height)
-{
-   png_byte buf[64];
-   png_size_t wlen, hlen, total_len;
-
-   png_debug(1, "in png_write_sCAL_s");
-
-   wlen = png_strlen(width);
-   hlen = png_strlen(height);
-   total_len = wlen + hlen + 2;
-
-   if (total_len > 64)
-   {
-      png_warning(png_ptr, "Can't write sCAL (buffer too small)");
-      return;
-   }
-
-   buf[0] = (png_byte)unit;
-   png_memcpy(buf + 1, width, wlen + 1);      /* Append the '\0' here */
-   png_memcpy(buf + wlen + 2, height, hlen);  /* Do NOT append the '\0' here */
-
-   png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
-   png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
-}
-#endif
-
-#ifdef PNG_WRITE_pHYs_SUPPORTED
-/* Write the pHYs chunk */
-void /* PRIVATE */
-png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
-    png_uint_32 y_pixels_per_unit,
-    int unit_type)
-{
-   png_byte buf[9];
-
-   png_debug(1, "in png_write_pHYs");
-
-   if (unit_type >= PNG_RESOLUTION_LAST)
-      png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
-
-   png_save_uint_32(buf, x_pixels_per_unit);
-   png_save_uint_32(buf + 4, y_pixels_per_unit);
-   buf[8] = (png_byte)unit_type;
-
-   png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
-}
-#endif
-
-#ifdef PNG_WRITE_tIME_SUPPORTED
-/* Write the tIME chunk.  Use either png_convert_from_struct_tm()
- * or png_convert_from_time_t(), or fill in the structure yourself.
- */
-void /* PRIVATE */
-png_write_tIME(png_structp png_ptr, png_const_timep mod_time)
-{
-   png_byte buf[7];
-
-   png_debug(1, "in png_write_tIME");
-
-   if (mod_time->month  > 12 || mod_time->month  < 1 ||
-       mod_time->day    > 31 || mod_time->day    < 1 ||
-       mod_time->hour   > 23 || mod_time->second > 60)
-   {
-      png_warning(png_ptr, "Invalid time specified for tIME chunk");
-      return;
-   }
-
-   png_save_uint_16(buf, mod_time->year);
-   buf[2] = mod_time->month;
-   buf[3] = mod_time->day;
-   buf[4] = mod_time->hour;
-   buf[5] = mod_time->minute;
-   buf[6] = mod_time->second;
-
-   png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
-}
-#endif
-
-/* Initializes the row writing capability of libpng */
-void /* PRIVATE */
-png_write_start_row(png_structp png_ptr)
-{
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
-   /* Start of interlace block */
-   static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
-   /* Offset to next interlace block */
-   static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
-   /* Start of interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
-   /* Offset to next interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif
-
-   png_alloc_size_t buf_size;
-   int usr_pixel_depth;
-
-   png_debug(1, "in png_write_start_row");
-
-   usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
-   buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
-
-   /* 1.5.6: added to allow checking in the row write code. */
-   png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
-   png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
-
-   /* Set up row buffer */
-   png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size);
-
-   png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
-
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-   /* Set up filtering buffer, if using this filter */
-   if (png_ptr->do_filter & PNG_FILTER_SUB)
-   {
-      png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1);
-
-      png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
-   }
-
-   /* We only need to keep the previous row if we are using one of these. */
-   if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
-   {
-      /* Set up previous row buffer */
-      png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);
-
-      if (png_ptr->do_filter & PNG_FILTER_UP)
-      {
-         png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
-            png_ptr->rowbytes + 1);
-
-         png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
-      }
-
-      if (png_ptr->do_filter & PNG_FILTER_AVG)
-      {
-         png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
-             png_ptr->rowbytes + 1);
-
-         png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
-      }
-
-      if (png_ptr->do_filter & PNG_FILTER_PAETH)
-      {
-         png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
-             png_ptr->rowbytes + 1);
-
-         png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
-      }
-   }
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   /* If interlaced, we need to set up width and height of pass */
-   if (png_ptr->interlaced)
-   {
-      if (!(png_ptr->transformations & PNG_INTERLACE))
-      {
-         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
-             png_pass_ystart[0]) / png_pass_yinc[0];
-
-         png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
-             png_pass_start[0]) / png_pass_inc[0];
-      }
-
-      else
-      {
-         png_ptr->num_rows = png_ptr->height;
-         png_ptr->usr_width = png_ptr->width;
-      }
-   }
-
-   else
-#endif
-   {
-      png_ptr->num_rows = png_ptr->height;
-      png_ptr->usr_width = png_ptr->width;
-   }
-
-   png_zlib_claim(png_ptr, PNG_ZLIB_FOR_IDAT);
-   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-   png_ptr->zstream.next_out = png_ptr->zbuf;
-}
-
-/* Internal use only.  Called when finished processing a row of data. */
-void /* PRIVATE */
-png_write_finish_row(png_structp png_ptr)
-{
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
-   /* Start of interlace block */
-   static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
-   /* Offset to next interlace block */
-   static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
-   /* Start of interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
-   /* Offset to next interlace block in the y direction */
-   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif
-
-   int ret;
-
-   png_debug(1, "in png_write_finish_row");
-
-   /* Next row */
-   png_ptr->row_number++;
-
-   /* See if we are done */
-   if (png_ptr->row_number < png_ptr->num_rows)
-      return;
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   /* If interlaced, go to next pass */
-   if (png_ptr->interlaced)
-   {
-      png_ptr->row_number = 0;
-      if (png_ptr->transformations & PNG_INTERLACE)
-      {
-         png_ptr->pass++;
-      }
-
-      else
-      {
-         /* Loop until we find a non-zero width or height pass */
-         do
-         {
-            png_ptr->pass++;
-
-            if (png_ptr->pass >= 7)
-               break;
-
-            png_ptr->usr_width = (png_ptr->width +
-                png_pass_inc[png_ptr->pass] - 1 -
-                png_pass_start[png_ptr->pass]) /
-                png_pass_inc[png_ptr->pass];
-
-            png_ptr->num_rows = (png_ptr->height +
-                png_pass_yinc[png_ptr->pass] - 1 -
-                png_pass_ystart[png_ptr->pass]) /
-                png_pass_yinc[png_ptr->pass];
-
-            if (png_ptr->transformations & PNG_INTERLACE)
-               break;
-
-         } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
-
-      }
-
-      /* Reset the row above the image for the next pass */
-      if (png_ptr->pass < 7)
-      {
-         if (png_ptr->prev_row != NULL)
-            png_memset(png_ptr->prev_row, 0,
-                (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
-                png_ptr->usr_bit_depth, png_ptr->width)) + 1);
-
-         return;
-      }
-   }
-#endif
-
-   /* If we get here, we've just written the last row, so we need
-      to flush the compressor */
-   do
-   {
-      /* Tell the compressor we are done */
-      ret = deflate(&png_ptr->zstream, Z_FINISH);
-
-      /* Check for an error */
-      if (ret == Z_OK)
-      {
-         /* Check to see if we need more room */
-         if (!(png_ptr->zstream.avail_out))
-         {
-            png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
-            png_ptr->zstream.next_out = png_ptr->zbuf;
-            png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-         }
-      }
-
-      else if (ret != Z_STREAM_END)
-      {
-         if (png_ptr->zstream.msg != NULL)
-            png_error(png_ptr, png_ptr->zstream.msg);
-
-         else
-            png_error(png_ptr, "zlib error");
-      }
-   } while (ret != Z_STREAM_END);
-
-   /* Write any extra space */
-   if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
-   {
-      png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
-          png_ptr->zstream.avail_out);
-   }
-
-   png_zlib_release(png_ptr);
-   png_ptr->zstream.data_type = Z_BINARY;
-}
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-/* Pick out the correct pixels for the interlace pass.
- * The basic idea here is to go through the row with a source
- * pointer and a destination pointer (sp and dp), and copy the
- * correct pixels for the pass.  As the row gets compacted,
- * sp will always be >= dp, so we should never overwrite anything.
- * See the default: case for the easiest code to understand.
- */
-void /* PRIVATE */
-png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
-{
-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
-   /* Start of interlace block */
-   static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
-   /* Offset to next interlace block */
-   static PNG_CONST png_byte  png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
-   png_debug(1, "in png_do_write_interlace");
-
-   /* We don't have to do anything on the last pass (6) */
-   if (pass < 6)
-   {
-      /* Each pixel depth is handled separately */
-      switch (row_info->pixel_depth)
-      {
-         case 1:
-         {
-            png_bytep sp;
-            png_bytep dp;
-            int shift;
-            int d;
-            int value;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            dp = row;
-            d = 0;
-            shift = 7;
-
-            for (i = png_pass_start[pass]; i < row_width;
-               i += png_pass_inc[pass])
-            {
-               sp = row + (png_size_t)(i >> 3);
-               value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
-               d |= (value << shift);
-
-               if (shift == 0)
-               {
-                  shift = 7;
-                  *dp++ = (png_byte)d;
-                  d = 0;
-               }
-
-               else
-                  shift--;
-
-            }
-            if (shift != 7)
-               *dp = (png_byte)d;
-
-            break;
-         }
-
-         case 2:
-         {
-            png_bytep sp;
-            png_bytep dp;
-            int shift;
-            int d;
-            int value;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            dp = row;
-            shift = 6;
-            d = 0;
-
-            for (i = png_pass_start[pass]; i < row_width;
-               i += png_pass_inc[pass])
-            {
-               sp = row + (png_size_t)(i >> 2);
-               value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
-               d |= (value << shift);
-
-               if (shift == 0)
-               {
-                  shift = 6;
-                  *dp++ = (png_byte)d;
-                  d = 0;
-               }
-
-               else
-                  shift -= 2;
-            }
-            if (shift != 6)
-               *dp = (png_byte)d;
-
-            break;
-         }
-
-         case 4:
-         {
-            png_bytep sp;
-            png_bytep dp;
-            int shift;
-            int d;
-            int value;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-
-            dp = row;
-            shift = 4;
-            d = 0;
-            for (i = png_pass_start[pass]; i < row_width;
-                i += png_pass_inc[pass])
-            {
-               sp = row + (png_size_t)(i >> 1);
-               value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
-               d |= (value << shift);
-
-               if (shift == 0)
-               {
-                  shift = 4;
-                  *dp++ = (png_byte)d;
-                  d = 0;
-               }
-
-               else
-                  shift -= 4;
-            }
-            if (shift != 4)
-               *dp = (png_byte)d;
-
-            break;
-         }
-
-         default:
-         {
-            png_bytep sp;
-            png_bytep dp;
-            png_uint_32 i;
-            png_uint_32 row_width = row_info->width;
-            png_size_t pixel_bytes;
-
-            /* Start at the beginning */
-            dp = row;
-
-            /* Find out how many bytes each pixel takes up */
-            pixel_bytes = (row_info->pixel_depth >> 3);
-
-            /* Loop through the row, only looking at the pixels that matter */
-            for (i = png_pass_start[pass]; i < row_width;
-               i += png_pass_inc[pass])
-            {
-               /* Find out where the original pixel is */
-               sp = row + (png_size_t)i * pixel_bytes;
-
-               /* Move the pixel */
-               if (dp != sp)
-                  png_memcpy(dp, sp, pixel_bytes);
-
-               /* Next pixel */
-               dp += pixel_bytes;
-            }
-            break;
-         }
-      }
-      /* Set new row width */
-      row_info->width = (row_info->width +
-          png_pass_inc[pass] - 1 -
-          png_pass_start[pass]) /
-          png_pass_inc[pass];
-
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
-          row_info->width);
-   }
-}
-#endif
-
-/* This filters the row, chooses which filter to use, if it has not already
- * been specified by the application, and then writes the row out with the
- * chosen filter.
- */
-static void png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row,
-   png_size_t row_bytes);
-
-#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
-#define PNG_HISHIFT 10
-#define PNG_LOMASK ((png_uint_32)0xffffL)
-#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
-void /* PRIVATE */
-png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
-{
-   png_bytep best_row;
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-   png_bytep prev_row, row_buf;
-   png_uint_32 mins, bpp;
-   png_byte filter_to_do = png_ptr->do_filter;
-   png_size_t row_bytes = row_info->rowbytes;
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   int num_p_filters = png_ptr->num_prev_filters;
-#endif
-
-   png_debug(1, "in png_write_find_filter");
-
-#ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-  if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS)
-  {
-     /* These will never be selected so we need not test them. */
-     filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH);
-  }
-#endif
-
-   /* Find out how many bytes offset each pixel is */
-   bpp = (row_info->pixel_depth + 7) >> 3;
-
-   prev_row = png_ptr->prev_row;
-#endif
-   best_row = png_ptr->row_buf;
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-   row_buf = best_row;
-   mins = PNG_MAXSUM;
-
-   /* The prediction method we use is to find which method provides the
-    * smallest value when summing the absolute values of the distances
-    * from zero, using anything >= 128 as negative numbers.  This is known
-    * as the "minimum sum of absolute differences" heuristic.  Other
-    * heuristics are the "weighted minimum sum of absolute differences"
-    * (experimental and can in theory improve compression), and the "zlib
-    * predictive" method (not implemented yet), which does test compressions
-    * of lines using different filter methods, and then chooses the
-    * (series of) filter(s) that give minimum compressed data size (VERY
-    * computationally expensive).
-    *
-    * GRR 980525:  consider also
-    *
-    *   (1) minimum sum of absolute differences from running average (i.e.,
-    *       keep running sum of non-absolute differences & count of bytes)
-    *       [track dispersion, too?  restart average if dispersion too large?]
-    *
-    *  (1b) minimum sum of absolute differences from sliding average, probably
-    *       with window size <= deflate window (usually 32K)
-    *
-    *   (2) minimum sum of squared differences from zero or running average
-    *       (i.e., ~ root-mean-square approach)
-    */
-
-
-   /* We don't need to test the 'no filter' case if this is the only filter
-    * that has been chosen, as it doesn't actually do anything to the data.
-    */
-   if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE)
-   {
-      png_bytep rp;
-      png_uint_32 sum = 0;
-      png_size_t i;
-      int v;
-
-      for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
-      {
-         v = *rp;
-         sum += (v < 128) ? v : 256 - v;
-      }
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         png_uint_32 sumhi, sumlo;
-         int j;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
-
-         /* Reduce the sum if we match any of the previous rows */
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
-            {
-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         /* Factor in the cost of this filter (this is here for completeness,
-          * but it makes no sense to have a "cost" for the NONE filter, as
-          * it has the minimum possible computational cost - none).
-          */
-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
-             PNG_COST_SHIFT;
-
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
-      }
-#endif
-      mins = sum;
-   }
-
-   /* Sub filter */
-   if (filter_to_do == PNG_FILTER_SUB)
-   /* It's the only filter so no testing is needed */
-   {
-      png_bytep rp, lp, dp;
-      png_size_t i;
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
-           i++, rp++, dp++)
-      {
-         *dp = *rp;
-      }
-
-      for (lp = row_buf + 1; i < row_bytes;
-         i++, rp++, lp++, dp++)
-      {
-         *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
-      }
-
-      best_row = png_ptr->sub_row;
-   }
-
-   else if (filter_to_do & PNG_FILTER_SUB)
-   {
-      png_bytep rp, dp, lp;
-      png_uint_32 sum = 0, lmins = mins;
-      png_size_t i;
-      int v;
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      /* We temporarily increase the "minimum sum" by the factor we
-       * would reduce the sum of this filter, so that we can do the
-       * early exit comparison without scaling the sum each time.
-       */
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 lmhi, lmlo;
-         lmlo = lmins & PNG_LOMASK;
-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
-            {
-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
-             PNG_COST_SHIFT;
-
-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
-             PNG_COST_SHIFT;
-
-         if (lmhi > PNG_HIMASK)
-            lmins = PNG_MAXSUM;
-
-         else
-            lmins = (lmhi << PNG_HISHIFT) + lmlo;
-      }
-#endif
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
-           i++, rp++, dp++)
-      {
-         v = *dp = *rp;
-
-         sum += (v < 128) ? v : 256 - v;
-      }
-
-      for (lp = row_buf + 1; i < row_bytes;
-         i++, rp++, lp++, dp++)
-      {
-         v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-
-         if (sum > lmins)  /* We are already worse, don't continue. */
-            break;
-      }
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 sumhi, sumlo;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
-            {
-               sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
-             PNG_COST_SHIFT;
-
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
-      }
-#endif
-
-      if (sum < mins)
-      {
-         mins = sum;
-         best_row = png_ptr->sub_row;
-      }
-   }
-
-   /* Up filter */
-   if (filter_to_do == PNG_FILTER_UP)
-   {
-      png_bytep rp, dp, pp;
-      png_size_t i;
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
-          pp = prev_row + 1; i < row_bytes;
-          i++, rp++, pp++, dp++)
-      {
-         *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
-      }
-
-      best_row = png_ptr->up_row;
-   }
-
-   else if (filter_to_do & PNG_FILTER_UP)
-   {
-      png_bytep rp, dp, pp;
-      png_uint_32 sum = 0, lmins = mins;
-      png_size_t i;
-      int v;
-
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 lmhi, lmlo;
-         lmlo = lmins & PNG_LOMASK;
-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
-            {
-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
-             PNG_COST_SHIFT;
-
-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
-             PNG_COST_SHIFT;
-
-         if (lmhi > PNG_HIMASK)
-            lmins = PNG_MAXSUM;
-
-         else
-            lmins = (lmhi << PNG_HISHIFT) + lmlo;
-      }
-#endif
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
-          pp = prev_row + 1; i < row_bytes; i++)
-      {
-         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-
-         if (sum > lmins)  /* We are already worse, don't continue. */
-            break;
-      }
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 sumhi, sumlo;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
-            {
-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
-             PNG_COST_SHIFT;
-
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
-      }
-#endif
-
-      if (sum < mins)
-      {
-         mins = sum;
-         best_row = png_ptr->up_row;
-      }
-   }
-
-   /* Avg filter */
-   if (filter_to_do == PNG_FILTER_AVG)
-   {
-      png_bytep rp, dp, pp, lp;
-      png_uint_32 i;
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
-           pp = prev_row + 1; i < bpp; i++)
-      {
-         *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
-      }
-
-      for (lp = row_buf + 1; i < row_bytes; i++)
-      {
-         *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
-                 & 0xff);
-      }
-      best_row = png_ptr->avg_row;
-   }
-
-   else if (filter_to_do & PNG_FILTER_AVG)
-   {
-      png_bytep rp, dp, pp, lp;
-      png_uint_32 sum = 0, lmins = mins;
-      png_size_t i;
-      int v;
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 lmhi, lmlo;
-         lmlo = lmins & PNG_LOMASK;
-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
-            {
-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
-             PNG_COST_SHIFT;
-
-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
-             PNG_COST_SHIFT;
-
-         if (lmhi > PNG_HIMASK)
-            lmins = PNG_MAXSUM;
-
-         else
-            lmins = (lmhi << PNG_HISHIFT) + lmlo;
-      }
-#endif
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
-           pp = prev_row + 1; i < bpp; i++)
-      {
-         v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-      }
-
-      for (lp = row_buf + 1; i < row_bytes; i++)
-      {
-         v = *dp++ =
-             (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-
-         if (sum > lmins)  /* We are already worse, don't continue. */
-            break;
-      }
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 sumhi, sumlo;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
-            {
-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
-             PNG_COST_SHIFT;
-
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
-      }
-#endif
-
-      if (sum < mins)
-      {
-         mins = sum;
-         best_row = png_ptr->avg_row;
-      }
-   }
-
-   /* Paeth filter */
-   if (filter_to_do == PNG_FILTER_PAETH)
-   {
-      png_bytep rp, dp, pp, cp, lp;
-      png_size_t i;
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
-          pp = prev_row + 1; i < bpp; i++)
-      {
-         *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
-      }
-
-      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
-      {
-         int a, b, c, pa, pb, pc, p;
-
-         b = *pp++;
-         c = *cp++;
-         a = *lp++;
-
-         p = b - c;
-         pc = a - c;
-
-#ifdef PNG_USE_ABS
-         pa = abs(p);
-         pb = abs(pc);
-         pc = abs(p + pc);
-#else
-         pa = p < 0 ? -p : p;
-         pb = pc < 0 ? -pc : pc;
-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#endif
-
-         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
-
-         *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
-      }
-      best_row = png_ptr->paeth_row;
-   }
-
-   else if (filter_to_do & PNG_FILTER_PAETH)
-   {
-      png_bytep rp, dp, pp, cp, lp;
-      png_uint_32 sum = 0, lmins = mins;
-      png_size_t i;
-      int v;
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 lmhi, lmlo;
-         lmlo = lmins & PNG_LOMASK;
-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
-            {
-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
-             PNG_COST_SHIFT;
-
-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
-             PNG_COST_SHIFT;
-
-         if (lmhi > PNG_HIMASK)
-            lmins = PNG_MAXSUM;
-
-         else
-            lmins = (lmhi << PNG_HISHIFT) + lmlo;
-      }
-#endif
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
-          pp = prev_row + 1; i < bpp; i++)
-      {
-         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-      }
-
-      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
-      {
-         int a, b, c, pa, pb, pc, p;
-
-         b = *pp++;
-         c = *cp++;
-         a = *lp++;
-
-#ifndef PNG_SLOW_PAETH
-         p = b - c;
-         pc = a - c;
-#ifdef PNG_USE_ABS
-         pa = abs(p);
-         pb = abs(pc);
-         pc = abs(p + pc);
-#else
-         pa = p < 0 ? -p : p;
-         pb = pc < 0 ? -pc : pc;
-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#endif
-         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
-#else /* PNG_SLOW_PAETH */
-         p = a + b - c;
-         pa = abs(p - a);
-         pb = abs(p - b);
-         pc = abs(p - c);
-
-         if (pa <= pb && pa <= pc)
-            p = a;
-
-         else if (pb <= pc)
-            p = b;
-
-         else
-            p = c;
-#endif /* PNG_SLOW_PAETH */
-
-         v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-
-         if (sum > lmins)  /* We are already worse, don't continue. */
-            break;
-      }
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 sumhi, sumlo;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
-            {
-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
-             PNG_COST_SHIFT;
-
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
-      }
-#endif
-
-      if (sum < mins)
-      {
-         best_row = png_ptr->paeth_row;
-      }
-   }
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
-
-   /* Do the actual writing of the filtered row data from the chosen filter. */
-   png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
-
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   /* Save the type of filter we picked this time for future calculations */
-   if (png_ptr->num_prev_filters > 0)
-   {
-      int j;
-
-      for (j = 1; j < num_p_filters; j++)
-      {
-         png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
-      }
-
-      png_ptr->prev_filters[j] = best_row[0];
-   }
-#endif
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
-}
-
-
-/* Do the actual writing of a previously filtered row. */
-static void
-png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row,
-   png_size_t avail/*includes filter byte*/)
-{
-   png_debug(1, "in png_write_filtered_row");
-
-   png_debug1(2, "filter = %d", filtered_row[0]);
-   /* Set up the zlib input buffer */
-
-   png_ptr->zstream.next_in = filtered_row;
-   png_ptr->zstream.avail_in = 0;
-   /* Repeat until we have compressed all the data */
-   do
-   {
-      int ret; /* Return of zlib */
-
-      /* Record the number of bytes available - zlib supports at least 65535
-       * bytes at one step, depending on the size of the zlib type 'uInt', the
-       * maximum size zlib can write at once is ZLIB_IO_MAX (from pngpriv.h).
-       * Use this because on 16 bit systems 'rowbytes' can be up to 65536 (i.e.
-       * one more than 16 bits) and, in this case 'rowbytes+1' can overflow a
-       * uInt.  ZLIB_IO_MAX can be safely reduced to cause zlib to be called
-       * with smaller chunks of data.
-       */
-      if (png_ptr->zstream.avail_in == 0)
-      {
-         if (avail > ZLIB_IO_MAX)
-         {
-            png_ptr->zstream.avail_in  = ZLIB_IO_MAX;
-            avail -= ZLIB_IO_MAX;
-         }
-
-         else
-         {
-            /* So this will fit in the available uInt space: */
-            png_ptr->zstream.avail_in = (uInt)avail;
-            avail = 0;
-         }
-      }
-
-      /* Compress the data */
-      ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
-
-      /* Check for compression errors */
-      if (ret != Z_OK)
-      {
-         if (png_ptr->zstream.msg != NULL)
-            png_error(png_ptr, png_ptr->zstream.msg);
-
-         else
-            png_error(png_ptr, "zlib error");
-      }
-
-      /* See if it is time to write another IDAT */
-      if (!(png_ptr->zstream.avail_out))
-      {
-         /* Write the IDAT and reset the zlib output buffer */
-         png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
-      }
-   /* Repeat until all data has been compressed */
-   } while (avail > 0 || png_ptr->zstream.avail_in > 0);
-
-   /* Swap the current and previous rows */
-   if (png_ptr->prev_row != NULL)
-   {
-      png_bytep tptr;
-
-      tptr = png_ptr->prev_row;
-      png_ptr->prev_row = png_ptr->row_buf;
-      png_ptr->row_buf = tptr;
-   }
-
-   /* Finish row - updates counters and flushes zlib if last row */
-   png_write_finish_row(png_ptr);
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-   png_ptr->flush_rows++;
-
-   if (png_ptr->flush_dist > 0 &&
-       png_ptr->flush_rows >= png_ptr->flush_dist)
-   {
-      png_write_flush(png_ptr);
-   }
-#endif
-}
-#endif /* PNG_WRITE_SUPPORTED */
diff --git a/extern/libpng/include/projects/owatcom/libpng.tgt b/extern/libpng/include/projects/owatcom/libpng.tgt
deleted file mode 100644
index 4a9622e68c..0000000000
--- a/extern/libpng/include/projects/owatcom/libpng.tgt
+++ /dev/null
@@ -1,383 +0,0 @@
-40
-targetIdent
-0
-MProject
-1
-MComponent
-0
-2
-WString
-3
-LIB
-3
-WString
-5
-n_2sn
-1
-0
-0
-4
-MCommand
-0
-5
-MCommand
-0
-6
-MItem
-10
-libpng.lib
-7
-WString
-3
-LIB
-8
-WVList
-0
-9
-WVList
-1
-10
-ActionStates
-11
-WString
-5
-&Make
-12
-WVList
-0
--1
-1
-1
-0
-13
-WPickList
-16
-14
-MItem
-3
-*.c
-15
-WString
-4
-COBJ
-16
-WVList
-2
-17
-MVState
-18
-WString
-3
-WCC
-19
-WString
-25
-n????Include directories:
-1
-20
-WString
-39
-"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
-0
-21
-MVState
-22
-WString
-3
-WCC
-23
-WString
-25
-n????Include directories:
-0
-24
-WString
-39
-"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
-0
-25
-WVList
-1
-26
-ActionStates
-27
-WString
-5
-&Make
-28
-WVList
-0
--1
-1
-1
-0
-29
-MItem
-11
-..\..\png.c
-30
-WString
-4
-COBJ
-31
-WVList
-0
-32
-WVList
-0
-14
-1
-1
-0
-33
-MItem
-16
-..\..\pngerror.c
-34
-WString
-4
-COBJ
-35
-WVList
-0
-36
-WVList
-0
-14
-1
-1
-0
-37
-MItem
-14
-..\..\pngget.c
-38
-WString
-4
-COBJ
-39
-WVList
-0
-40
-WVList
-0
-14
-1
-1
-0
-41
-MItem
-14
-..\..\pngmem.c
-42
-WString
-4
-COBJ
-43
-WVList
-0
-44
-WVList
-0
-14
-1
-1
-0
-45
-MItem
-16
-..\..\pngpread.c
-46
-WString
-4
-COBJ
-47
-WVList
-0
-48
-WVList
-0
-14
-1
-1
-0
-49
-MItem
-15
-..\..\pngread.c
-50
-WString
-4
-COBJ
-51
-WVList
-0
-52
-WVList
-0
-14
-1
-1
-0
-53
-MItem
-14
-..\..\pngrio.c
-54
-WString
-4
-COBJ
-55
-WVList
-0
-56
-WVList
-0
-14
-1
-1
-0
-57
-MItem
-16
-..\..\pngrtran.c
-58
-WString
-4
-COBJ
-59
-WVList
-0
-60
-WVList
-0
-14
-1
-1
-0
-61
-MItem
-16
-..\..\pngrutil.c
-62
-WString
-4
-COBJ
-63
-WVList
-0
-64
-WVList
-0
-14
-1
-1
-0
-65
-MItem
-14
-..\..\pngset.c
-66
-WString
-4
-COBJ
-67
-WVList
-0
-68
-WVList
-0
-14
-1
-1
-0
-69
-MItem
-16
-..\..\pngtrans.c
-70
-WString
-4
-COBJ
-71
-WVList
-0
-72
-WVList
-0
-14
-1
-1
-0
-73
-MItem
-14
-..\..\pngwio.c
-74
-WString
-4
-COBJ
-75
-WVList
-0
-76
-WVList
-0
-14
-1
-1
-0
-77
-MItem
-16
-..\..\pngwrite.c
-78
-WString
-4
-COBJ
-79
-WVList
-0
-80
-WVList
-0
-14
-1
-1
-0
-81
-MItem
-16
-..\..\pngwtran.c
-82
-WString
-4
-COBJ
-83
-WVList
-0
-84
-WVList
-0
-14
-1
-1
-0
-85
-MItem
-16
-..\..\pngwutil.c
-86
-WString
-4
-COBJ
-87
-WVList
-0
-88
-WVList
-0
-14
-1
-1
-0
diff --git a/extern/libpng/include/projects/owatcom/libpng.wpj b/extern/libpng/include/projects/owatcom/libpng.wpj
deleted file mode 100644
index cddf9f1f10..0000000000
--- a/extern/libpng/include/projects/owatcom/libpng.wpj
+++ /dev/null
@@ -1,92 +0,0 @@
-40
-projectIdent
-0
-VpeMain
-1
-WRect
-256
-0
-8960
-9284
-2
-MProject
-3
-MCommand
-322
-# Locations of zlib and (if required) awk (change as required:)
-set zlib=..\..\..\zlib
-set awk=
-#
-@if not exist pngconfig.dfa $(MAKE) $(__MAKEOPTS__) -f pngconfig.mak defaults
-@if exist config.inf type config.inf
-@echo Checking for the libpng configuration file pnglibconf.h
-$(MAKE) $(__MAKEOPTS__) -f pngconfig.mak
-4
-MCommand
-19
-@type pngconfig.inf
-3
-5
-WFileName
-10
-libpng.tgt
-6
-WFileName
-11
-pngtest.tgt
-7
-WFileName
-12
-pngvalid.tgt
-8
-WVList
-3
-9
-VComponent
-10
-WRect
-0
-0
-5632
-4164
-0
-0
-11
-WFileName
-10
-libpng.tgt
-0
-0
-12
-VComponent
-13
-WRect
-1280
-1540
-5632
-4164
-0
-0
-14
-WFileName
-11
-pngtest.tgt
-0
-1
-15
-VComponent
-16
-WRect
-518
-487
-5632
-4164
-0
-0
-17
-WFileName
-12
-pngvalid.tgt
-0
-1
-9
diff --git a/extern/libpng/include/projects/owatcom/pngconfig.mak b/extern/libpng/include/projects/owatcom/pngconfig.mak
deleted file mode 100644
index 054a3fc207..0000000000
--- a/extern/libpng/include/projects/owatcom/pngconfig.mak
+++ /dev/null
@@ -1,160 +0,0 @@
-# This is an OpenWatcom make file which builds pnglibconf.h - the libpng
-# configuration header.  You can ignore this file if you don't need to
-# configure libpng; a default configuration will be built.
-#
-# For more information build libpng.wpj under the IDE and then read the
-# generated files:
-#
-#    config.inf: Basic configuration information for a standard build.
-#    pngconfig.dfa: Advanced configuration for non-standard libpng builds.
-#
-DELETE=rm -f
-ECHO=echo
-COPY=copy
-#
-# If your configuration needs to test compiler flags when building
-# pnglibconf.h you may need to override the following on the wmake command
-# line:
-CFLAGS=
-CC=wcl386
-CPP=$(CC) -pw0
-#
-# Read awk from the environment if set, else it can be set on the command
-# line (the default approach is to set the %awk% environment variable in the
-# IDE libpng.wpj 'before' rule - this setting is local.)
-!ifdef %awk
-AWK=$(%awk)
-!endif
-#
-# pnglibconf.h must exist in the source directory, this is the final rule
-# which copies the local built version (and this is the default target for
-# this makefile.)
-..\..\pnglibconf.h: pnglibconf.h
- $(COPY) pnglibconf.h $@
-
-!ifdef AWK
-# CPPFLAGS should contain the options to control the result,
-# but DEFS and CFLAGS are also supported here, override
-# as appropriate
-DFNFLAGS = $(DEFS) $(CPPFLAGS) $(CFLAGS)
-
-pnglibconf.h: pnglibconf.dfn
- $(DELETE) $@ dfn.c dfn1.out dfn2.out
- $(ECHO) $#include "pnglibconf.dfn" >dfn.c
- $(CPP) $(DFNFLAGS) dfn.c >dfn1.out
- $(AWK) -f << dfn1.out >dfn2.out
-/^.*PNG_DEFN_MAGIC-.*-PNG_DEFN_END.*$$/{
- sub(/^.*PNG_DEFN_MAGIC-/, "")
- sub(/ *-PNG_DEFN_END.*$$/, "")
- gsub(/ *@@@ */, "")
- print
-}
-<<
- $(COPY) dfn2.out $@
- @type << >pngconfig.inf
-This is a locally configurable build of libpng.lib; for configuration
-instructions consult and edit projects/openwatcom/pngconfig.dfa
-<<
- $(DELETE) dfn.c dfn1.out dfn2.out
-
-pnglibconf.dfn: ..\..\scripts\pnglibconf.dfa ..\..\scripts\options.awk pngconfig.dfa ..\..\pngconf.h
- $(DELETE) $@ dfn1.out dfn2.out
- $(AWK) -f ..\..\scripts\options.awk out=dfn1.out version=search ..\..\pngconf.h ..\..\scripts\pnglibconf.dfa pngconfig.dfa $(DFA_XTRA) 1>&2
- $(AWK) -f ..\..\scripts\options.awk out=dfn2.out dfn1.out 1>&2
- $(COPY) dfn2.out $@
- $(DELETE) dfn1.out dfn2.out
-
-!else
-# The following lines are used to copy scripts\pnglibconf.h.prebuilt and make
-# the required change to the calling convention.
-#
-# By default libpng is built to use the __cdecl calling convention on
-# Windows.  This gives compatibility with MSVC and GCC.  Unfortunately it
-# does not work with OpenWatcom because OpenWatcom implements longjmp using
-# the __watcall convention (compared with both MSVC and GCC which use __cdecl
-# for library functions.)
-#
-# Thus the default must be changed to build on OpenWatcom and, once changed,
-# the result will not be compatible with applications built using other
-# compilers (in fact attempts to build will fail at compile time.)
-#
-pnglibconf.h: ..\..\scripts\pnglibconf.h.prebuilt .existsonly
- @$(ECHO) .
- @$(ECHO) .
- @$(ECHO) $$(AWK) NOT AVAILABLE: COPYING scripts\pnglibconf.h.prebuilt
- @$(ECHO) .
- @$(ECHO) .
- vi -q -k ":1,$$s/PNG_API_RULE 0$$/PNG_API_RULE 2/\n:w! $@\n:q!\n" ..\..\scripts\pnglibconf.h.prebuilt
- @$(ECHO) .
- @$(ECHO) .
- @$(ECHO) YOU HAVE A DEFAULT CONFIGURATION BECAUSE YOU DO NOT HAVE AWK!
- @$(ECHO) .
- @$(ECHO) .
- @type << >pngconfig.inf
-This is the default configuration of libpng.lib, if you wish to
-change the configuration please consult the instructions in
-projects/owatcom/pngconfig.dfa.
-<<
-
-!endif
-
-# Make the default files
-defaults: .symbolic
- @$(COPY) << config.inf
-$# The libpng project is incompletely configured.  To complete configuration
-$# please complete the following steps:
-$#
-$#   1) Edit the 'before' rule of libpng.wpj (from the IDE) to define the
-$#      locations of the zlib include file zlib.h and the built zlib library,
-$#      zlib.lib.
-$#
-$#   2) If you want to change libpng to a non-standard configuration also
-$#      change the definition of 'awk' in the before rule to the name of your
-$#      awk command.  For more instructions on configuration read
-$#      pngconfig.dfa.
-$#
-$#   3) Delete this file (config.inf).
-<<
- @$(COPY) << pngconfig.dfa
-$# pngconfig.dfa: this file contains configuration options for libpng.
-$# If emtpy the standard configuration will be built.  For this file to be
-$# used a working version of the program 'awk' is required and the program
-$# must be identified in the 'before' rule of the project.
-$#
-$# If you don't already have 'awk', or the version of awk you have seems not
-$# to work, download Brian Kernighan's awk (Brian Kernighan is the author of
-$# awk.)  You can find source code and a built executable (called awk95.exe)
-$# here:
-$#
-$#     http://www.cs.princeton.edu/~bwk/btl.mirror/
-$#
-$# The executable works just fine.
-$#
-$# If build issues errors after a change to pngconfig.dfa you have entered
-$# inconsistent feature requests, or even malformed requests, in
-$# pngconfig.dfa.  The error messages from awk should be comprehensible, but
-$# if not simply go back to the start (nothing but comments in this file) and
-$# enter configuration lines one by one until one produces an error.  (Or, of
-$# course, do the standard binary chop.)
-$#
-$# You need to rebuild everything after a change to pnglibconf.dfa - i.e. you
-$# must do Actions/Mark All Targets for Remake.  This is because the compiler
-$# generated dependency information (as of OpenWatcom 1.9) does not record the
-$# dependency on pnglibconf.h correctly.
-$#
-$# If awk isn't set then this file is bypassed.  If you just want the standard
-$# configuration it is automatically produced from the distributed version
-$# (scripts\pnglibconf.h.prebuilt) by editting PNG_API_RULE to 2 (to force use
-$# of the OpenWatcom library calling convention.)
-$#
-<<
-
-clean:: .symbolic
- $(DELETE) ..\..\pnglibconf.h pnglibconf.* dfn.c *.out pngconfig.inf
- $(DELETE) *.obj *.mbr *.sym *.err *.pch libpng.mk
- $(DELETE) libpng.lib libpng.lbr libpng.lb1 libpng.cbr libpng.mk1
- $(DELETE) pngtest.exe pngtest.map pngtest.lk1 pngtest.mk1
- $(DELETE) pngvalid.exe pngvalid.map pngvalid.lk1 pngvalid.mk1
-
-distclean:: clean .symbolic
- $(DELETE) zlib.inf awk.inf config.inf pngconfig.dfa
diff --git a/extern/libpng/include/projects/owatcom/pngtest.tgt b/extern/libpng/include/projects/owatcom/pngtest.tgt
deleted file mode 100644
index 211f1a7488..0000000000
--- a/extern/libpng/include/projects/owatcom/pngtest.tgt
+++ /dev/null
@@ -1,179 +0,0 @@
-40
-targetIdent
-0
-MProject
-1
-MComponent
-0
-2
-WString
-4
-NEXE
-3
-WString
-5
-nc2en
-1
-0
-0
-4
-MCommand
-0
-5
-MCommand
-34
-cd ..\..
-projects\owatcom\pngtest
-6
-MItem
-11
-pngtest.exe
-7
-WString
-4
-NEXE
-8
-WVList
-4
-9
-MVState
-10
-WString
-7
-WINLINK
-11
-WString
-28
-?????Library directories(;):
-1
-12
-WString
-8
-$(%zlib)
-0
-13
-MVState
-14
-WString
-7
-WINLINK
-15
-WString
-18
-?????Libraries(,):
-1
-16
-WString
-19
-libpng.lib zlib.lib
-0
-17
-MVState
-18
-WString
-7
-WINLINK
-19
-WString
-28
-?????Library directories(;):
-0
-20
-WString
-8
-$(%zlib)
-0
-21
-MVState
-22
-WString
-7
-WINLINK
-23
-WString
-18
-?????Libraries(,):
-0
-24
-WString
-19
-libpng.lib zlib.lib
-0
-25
-WVList
-0
--1
-1
-1
-0
-26
-WPickList
-2
-27
-MItem
-3
-*.c
-28
-WString
-4
-COBJ
-29
-WVList
-2
-30
-MVState
-31
-WString
-3
-WCC
-32
-WString
-25
-n????Include directories:
-1
-33
-WString
-39
-"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
-0
-34
-MVState
-35
-WString
-3
-WCC
-36
-WString
-25
-n????Include directories:
-0
-37
-WString
-39
-"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
-0
-38
-WVList
-0
--1
-1
-1
-0
-39
-MItem
-15
-..\..\pngtest.c
-40
-WString
-4
-COBJ
-41
-WVList
-0
-42
-WVList
-0
-27
-1
-1
-0
diff --git a/extern/libpng/include/projects/owatcom/pngvalid.tgt b/extern/libpng/include/projects/owatcom/pngvalid.tgt
deleted file mode 100644
index 1e78e75cb6..0000000000
--- a/extern/libpng/include/projects/owatcom/pngvalid.tgt
+++ /dev/null
@@ -1,210 +0,0 @@
-40
-targetIdent
-0
-MProject
-1
-MComponent
-0
-2
-WString
-4
-NEXE
-3
-WString
-5
-nc2en
-1
-0
-0
-4
-MCommand
-0
-5
-MCommand
-8
-pngvalid
-6
-MItem
-12
-pngvalid.exe
-7
-WString
-4
-NEXE
-8
-WVList
-6
-9
-MVState
-10
-WString
-7
-WINLINK
-11
-WString
-11
-?????Stack:
-1
-12
-WString
-4
-768k
-0
-13
-MVState
-14
-WString
-7
-WINLINK
-15
-WString
-28
-?????Library directories(;):
-1
-16
-WString
-8
-$(%zlib)
-0
-17
-MVState
-18
-WString
-7
-WINLINK
-19
-WString
-18
-?????Libraries(,):
-1
-20
-WString
-19
-libpng.lib zlib.lib
-0
-21
-MVState
-22
-WString
-7
-WINLINK
-23
-WString
-11
-?????Stack:
-0
-24
-WString
-4
-768k
-0
-25
-MVState
-26
-WString
-7
-WINLINK
-27
-WString
-28
-?????Library directories(;):
-0
-28
-WString
-8
-$(%zlib)
-0
-29
-MVState
-30
-WString
-7
-WINLINK
-31
-WString
-18
-?????Libraries(,):
-0
-32
-WString
-19
-libpng.lib zlib.lib
-0
-33
-WVList
-0
--1
-1
-1
-0
-34
-WPickList
-2
-35
-MItem
-3
-*.c
-36
-WString
-4
-COBJ
-37
-WVList
-2
-38
-MVState
-39
-WString
-3
-WCC
-40
-WString
-25
-n????Include directories:
-1
-41
-WString
-39
-"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
-0
-42
-MVState
-43
-WString
-3
-WCC
-44
-WString
-25
-n????Include directories:
-0
-45
-WString
-39
-"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
-0
-46
-WVList
-0
--1
-1
-1
-0
-47
-MItem
-33
-..\..\contrib\libtests\pngvalid.c
-48
-WString
-4
-COBJ
-49
-WVList
-0
-50
-WVList
-0
-35
-1
-1
-0
diff --git a/extern/libpng/include/projects/visualc71/PRJ0041.mak b/extern/libpng/include/projects/visualc71/PRJ0041.mak
deleted file mode 100644
index c7a68b503e..0000000000
--- a/extern/libpng/include/projects/visualc71/PRJ0041.mak
+++ /dev/null
@@ -1,21 +0,0 @@
-# Prevent "Cannot find missing dependency..." warnings while compiling
-# pngwin.rc (PRJ0041).
-
-all: $(IntDir)\alloc.h \
-	 $(IntDir)\fp.h \
-	 $(IntDir)\m68881.h \
-	 $(IntDir)\mem.h \
-	 $(IntDir)\pngusr.h \
-	 $(IntDir)\strings.h \
-	 $(IntDir)\unistd.h \
-	 $(IntDir)\unixio.h
-
-$(IntDir)\alloc.h \
-$(IntDir)\fp.h \
-$(IntDir)\m68881.h \
-$(IntDir)\mem.h \
-$(IntDir)\pngusr.h \
-$(IntDir)\strings.h \
-$(IntDir)\unistd.h \
-$(IntDir)\unixio.h:
-	@!echo.>$@
diff --git a/extern/libpng/include/projects/visualc71/README.txt b/extern/libpng/include/projects/visualc71/README.txt
deleted file mode 100644
index 625eefcab7..0000000000
--- a/extern/libpng/include/projects/visualc71/README.txt
+++ /dev/null
@@ -1,58 +0,0 @@
-Microsoft Developer Studio Project File, Format Version 7.10 for libpng.
-
-Copyright (C) 2004 Simon-Pierre Cadieux.
-
-This code is released under the libpng license.
-For conditions of distribution and use, see copyright notice in png.h
-
-NOTE: This project will be removed from libpng-1.5.0.  It has
-been replaced with the "vstudio" project.
-
-Assumptions:
-* The libpng source files are in ..\..
-* The zlib source files are in ..\..\..\zlib
-* The zlib project file is in . /* Warning: This is until the zlib project
-  files get intergrated into the next zlib release. The final zlib project
-  directory will then be ..\..\..\zlib\projects\visualc71. */
-
-To use:
-
-1) On the main menu, select "File | Open Solution".
-   Open "libpng.sln".
-
-2) Display the Solution Explorer view (Ctrl+Alt+L)
-
-3) Set one of the project as the StartUp project. If you just want to build the
-   binaries set "libpng" as the startup project (Select "libpng" tree view
-   item + Project | Set as StartUp project). If you want to build and test the
-   binaries set it to "pngtest" (Select "pngtest" tree view item +
-   Project | Set as StartUp project)
-
-4) Select "Build | Configuration Manager...".
-   Choose the configuration you wish to build.
-
-5) Select "Build | Clean Solution".
-
-6) Select "Build | Build Solution (Ctrl-Shift-B)"
-
-This project builds the libpng binaries as follows:
-
-* Win32_DLL_Release\libpng15.dll      DLL build
-* Win32_DLL_Debug\libpng15d.dll       DLL build (debug version)
-* Win32_DLL_VB\libpng15vb.dll         DLL build for Visual Basic, using stdcall
-* Win32_LIB_Release\libpng.lib        static build
-* Win32_LIB_Debug\libpngd.lib         static build (debug version)
-
-Notes:
-
-If you change anything in the source files, or select different compiler
-settings, please change the DLL name to something different than any of
-the above names. Also, make sure that in your "pngusr.h" you define
-PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX according to the
-instructions provided in "pngconf.h".
-
-All DLLs built by this project use the Microsoft dynamic C runtime library
-MSVCR71.DLL (MSVCR71D.DLL for debug versions).  If you distribute any of the
-above mentioned libraries you may have to include this DLL in your package.
-For a list of files that are redistributable in Visual Studio see
-$(VCINSTALLDIR)\redist.txt.
diff --git a/extern/libpng/include/projects/visualc71/README_zlib.txt b/extern/libpng/include/projects/visualc71/README_zlib.txt
deleted file mode 100644
index 81d11cbb57..0000000000
--- a/extern/libpng/include/projects/visualc71/README_zlib.txt
+++ /dev/null
@@ -1,44 +0,0 @@
-/* WARNING: This file was put in the LibPNG distribution for convenience only.
-            It is expected to be part of the next zlib release under
-            "projects\visualc71\README.txt." */
-
-Microsoft Developer Studio Project File, Format Version 7.10 for zlib.
-
-Copyright (C) 2004 Simon-Pierre Cadieux.
-Copyright (C) 2004 Cosmin Truta.
-
-This code is released under the libpng license.
-For conditions of distribution and use, see copyright notice in zlib.h.
-
-NOTE: This project will be removed from libpng-1.5.0.  It has
-been replaced with the "vstudio" project.
-
-To use:
-
-1) On the main menu, select "File | Open Solution".
-   Open "zlib.sln".
-
-2) Display the Solution Explorer view (Ctrl+Alt+L)
-
-3) Set one of the project as the StartUp project. If you just want to build the
-   binaries set "zlib" as the startup project (Select "zlib" tree view item +
-   Project | Set as StartUp project). If you want to build and test the
-   binaries set it to "example" (Select "example" tree view item + Project |
-   Set as StartUp project), If you want to build the minigzip utility set it to
-   "minigzip" (Select "minigzip" tree view item + Project | Set as StartUp
-   project
-
-4) Select "Build | Configuration Manager...".
-   Choose the configuration you wish to build.
-
-5) Select "Build | Clean Solution".
-
-6) Select "Build | Build Solution (Ctrl-Shift-B)"
-
-This project builds the zlib binaries as follows:
-
-* Win32_DLL_Release\zlib1.dll       DLL build
-* Win32_DLL_Debug\zlib1d.dll        DLL build (debug version)
-* Win32_LIB_Release\zlib.lib        static build
-* Win32_LIB_Debug\zlibd.lib         static build (debug version)
-
diff --git a/extern/libpng/include/projects/visualc71/libpng.sln b/extern/libpng/include/projects/visualc71/libpng.sln
deleted file mode 100644
index adce68aae0..0000000000
--- a/extern/libpng/include/projects/visualc71/libpng.sln
+++ /dev/null
@@ -1,60 +0,0 @@
-Microsoft Visual Studio Solution File, Format Version 8.00
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "libpng", "libpng.vcproj", "{0008960E-E0DD-41A6-8265-00B31DDB4C21}"
-	ProjectSection(ProjectDependencies) = postProject
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0} = {2D4F8105-7D21-454C-9932-B47CAB71A5C0}
-	EndProjectSection
-EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngtest", "pngtest.vcproj", "{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}"
-	ProjectSection(ProjectDependencies) = postProject
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21} = {0008960E-E0DD-41A6-8265-00B31DDB4C21}
-	EndProjectSection
-EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "zlib", "zlib.vcproj", "{2D4F8105-7D21-454C-9932-B47CAB71A5C0}"
-	ProjectSection(ProjectDependencies) = postProject
-	EndProjectSection
-EndProject
-Global
-	GlobalSection(SolutionConfiguration) = preSolution
-		DLL Debug = DLL Debug
-		DLL Release = DLL Release
-		DLL VB = DLL VB
-		LIB Debug = LIB Debug
-		LIB Release = LIB Release
-	EndGlobalSection
-	GlobalSection(ProjectConfiguration) = postSolution
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Debug.ActiveCfg = DLL Debug|Win32
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Debug.Build.0 = DLL Debug|Win32
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Release.ActiveCfg = DLL Release|Win32
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Release.Build.0 = DLL Release|Win32
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL VB.ActiveCfg = DLL VB|Win32
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL VB.Build.0 = DLL VB|Win32
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Debug.ActiveCfg = LIB Debug|Win32
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Debug.Build.0 = LIB Debug|Win32
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Release.ActiveCfg = LIB Release|Win32
-		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Release.Build.0 = LIB Release|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Debug.ActiveCfg = DLL Debug|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Debug.Build.0 = DLL Debug|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Release.ActiveCfg = DLL Release|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Release.Build.0 = DLL Release|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL VB.ActiveCfg = DLL VB|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL VB.Build.0 = DLL VB|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Debug.ActiveCfg = LIB Debug|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Debug.Build.0 = LIB Debug|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Release.ActiveCfg = LIB Release|Win32
-		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Release.Build.0 = LIB Release|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Debug.ActiveCfg = DLL Debug|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Debug.Build.0 = DLL Debug|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Release.ActiveCfg = DLL Release|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Release.Build.0 = DLL Release|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL VB.ActiveCfg = DLL Release|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL VB.Build.0 = DLL Release|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Debug.ActiveCfg = LIB Debug|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Debug.Build.0 = LIB Debug|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Release.ActiveCfg = LIB Release|Win32
-		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Release.Build.0 = LIB Release|Win32
-	EndGlobalSection
-	GlobalSection(ExtensibilityGlobals) = postSolution
-	EndGlobalSection
-	GlobalSection(ExtensibilityAddIns) = postSolution
-	EndGlobalSection
-EndGlobal
diff --git a/extern/libpng/include/projects/visualc71/libpng.vcproj b/extern/libpng/include/projects/visualc71/libpng.vcproj
deleted file mode 100644
index e17f4f7a8d..0000000000
--- a/extern/libpng/include/projects/visualc71/libpng.vcproj
+++ /dev/null
@@ -1,419 +0,0 @@
-<?xml version="1.0" encoding="Windows-1252"?>
-<VisualStudioProject
-	ProjectType="Visual C++"
-	Version="7.10"
-	Name="libpng"
-	RootNamespace="libpng">
-	<Platforms>
-		<Platform
-			Name="Win32"/>
-	</Platforms>
-	<Configurations>
-		<Configuration
-			Name="DLL Release|Win32"
-			OutputDirectory=".\Win32_DLL_Release"
-			IntermediateDirectory=".\Win32_DLL_Release"
-			ConfigurationType="2">
-			<Tool
-				Name="VCCLCompilerTool"
-				InlineFunctionExpansion="1"
-				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;NDEBUG;PNG_BUILD_DLL;ZLIB_DLL;_CRT_SECURE_NO_WARNINGS"
-				StringPooling="TRUE"
-				RuntimeLibrary="2"
-				EnableFunctionLevelLinking="TRUE"
-				UsePrecompiledHeader="3"
-				PrecompiledHeaderThrough="pngpriv.h"
-				WarningLevel="3"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/libpng15.dll"
-				LinkIncremental="1"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"
-				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"
-				PreprocessorDefinitions="NDEBUG"
-				Culture="1033"
-				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="DLL Debug|Win32"
-			OutputDirectory=".\Win32_DLL_Debug"
-			IntermediateDirectory=".\Win32_DLL_Debug"
-			ConfigurationType="2">
-			<Tool
-				Name="VCCLCompilerTool"
-				Optimization="0"
-				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;PNG_DEBUG=1;PNG_BUILD_DLL;ZLIB_DLL;_CRT_SECURE_NO_WARNINGS"
-				BasicRuntimeChecks="3"
-				RuntimeLibrary="3"
-				UsePrecompiledHeader="3"
-				PrecompiledHeaderThrough="pngpriv.h"
-				WarningLevel="3"
-				DebugInformationFormat="4"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/libpng15d.dll"
-				GenerateDebugInformation="TRUE"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"
-				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"
-				PreprocessorDefinitions="_DEBUG,PNG_DEBUG=1"
-				Culture="1033"
-				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="DLL VB|Win32"
-			OutputDirectory=".\Win32_DLL_VB"
-			IntermediateDirectory=".\Win32_DLL_VB"
-			ConfigurationType="2">
-			<Tool
-				Name="VCCLCompilerTool"
-				InlineFunctionExpansion="1"
-				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;NDEBUG;PNG_BUILD_DLL;ZLIB_DLL;PNGAPI=__stdcall;PNG_NO_MODULEDEF;PNG_LIBPNG_SPECIALBUILD;PNG_USER_PRIVATEBUILD;_CRT_SECURE_NO_WARNINGS"
-				StringPooling="TRUE"
-				RuntimeLibrary="2"
-				EnableFunctionLevelLinking="TRUE"
-				UsePrecompiledHeader="3"
-				PrecompiledHeaderThrough="pngpriv.h"
-				WarningLevel="3"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/libpng15vb.dll"
-				LinkIncremental="1"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"
-				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"
-				AdditionalOptions="/d PNG_NO_PEDANTIC_WARNINGS /d PNG_LIBPNG_DLLFNAME_POSTFIX=&quot;&quot;&quot;&quot;VB&quot;&quot;&quot;&quot; /d PNG_LIBPNG_SPECIALBUILD=&quot;&quot;&quot;&quot;__stdcall calling convention used for exported functions&quot;&quot;&quot;&quot;"
-				PreprocessorDefinitions="NDEBUG"
-				Culture="1033"
-				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="LIB Release|Win32"
-			OutputDirectory=".\Win32_LIB_Release"
-			IntermediateDirectory=".\Win32_LIB_Release"
-			ConfigurationType="4">
-			<Tool
-				Name="VCCLCompilerTool"
-				InlineFunctionExpansion="1"
-				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;NDEBUG;_CRT_SECURE_NO_WARNINGS"
-				StringPooling="TRUE"
-				RuntimeLibrary="0"
-				EnableFunctionLevelLinking="TRUE"
-				UsePrecompiledHeader="3"
-				PrecompiledHeaderThrough="pngpriv.h"
-				WarningLevel="3"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLibrarianTool"
-				OutputFile="$(OutDir)/libpng.lib"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"
-				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="LIB Debug|Win32"
-			OutputDirectory=".\Win32_LIB_Debug"
-			IntermediateDirectory=".\Win32_LIB_Debug"
-			ConfigurationType="4">
-			<Tool
-				Name="VCCLCompilerTool"
-				Optimization="0"
-				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;PNG_DEBUG=1;_CRT_SECURE_NO_WARNINGS"
-				BasicRuntimeChecks="3"
-				RuntimeLibrary="1"
-				UsePrecompiledHeader="3"
-				PrecompiledHeaderThrough="pngpriv.h"
-				WarningLevel="3"
-				DebugInformationFormat="4"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLibrarianTool"
-				OutputFile="$(OutDir)/libpngd.lib"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"
-				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-	</Configurations>
-	<References>
-	</References>
-	<Files>
-		<Filter
-			Name="Source Files"
-			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
-			<File
-				RelativePath="..\..\png.c">
-				<FileConfiguration
-					Name="DLL Release|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="0"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="DLL Debug|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="0"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="DLL VB|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="0"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Release|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="0"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Debug|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="0"/>
-				</FileConfiguration>
-			</File>
-			<File
-				RelativePath="..\..\pngerror.c">
-				<FileConfiguration
-					Name="DLL Release|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="1"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="DLL Debug|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="1"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="DLL VB|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="1"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Release|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="1"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Debug|Win32">
-					<Tool
-						Name="VCCLCompilerTool"
-						UsePrecompiledHeader="1"/>
-				</FileConfiguration>
-			</File>
-			<File
-				RelativePath="..\..\pngget.c">
-			</File>
-			<File
-				RelativePath="..\..\pngmem.c">
-			</File>
-			<File
-				RelativePath="..\..\pngpread.c">
-			</File>
-			<File
-				RelativePath="..\..\pngread.c">
-			</File>
-			<File
-				RelativePath="..\..\pngrio.c">
-			</File>
-			<File
-				RelativePath="..\..\pngrtran.c">
-			</File>
-			<File
-				RelativePath="..\..\pngrutil.c">
-			</File>
-			<File
-				RelativePath="..\..\pngset.c">
-			</File>
-			<File
-				RelativePath="..\..\pngtrans.c">
-			</File>
-			<File
-				RelativePath="..\..\pngwio.c">
-			</File>
-			<File
-				RelativePath="..\..\pngwrite.c">
-			</File>
-			<File
-				RelativePath="..\..\pngwtran.c">
-			</File>
-			<File
-				RelativePath="..\..\pngwutil.c">
-			</File>
-		</Filter>
-		<Filter
-			Name="Header Files"
-			Filter="h;hpp;hxx;hm;inl">
-			<File
-				RelativePath="..\..\png.h">
-			</File>
-			<File
-				RelativePath="..\..\pngconf.h">
-			</File>
-			<File
-				RelativePath="..\..\pngpriv.h">
-			</File>
-		</Filter>
-		<Filter
-			Name="Resource Files"
-			Filter="ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe">
-			<File
-				RelativePath="..\..\scripts\pngwin.rc">
-				<FileConfiguration
-					Name="LIB Release|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCResourceCompilerTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Debug|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCResourceCompilerTool"/>
-				</FileConfiguration>
-			</File>
-		</Filter>
-		<File
-			RelativePath=".\PRJ0041.mak">
-			<FileConfiguration
-				Name="DLL Release|Win32">
-				<Tool
-					Name="VCCustomBuildTool"
-					Description="Create dummy include files to prevent &quot;Cannot find missing dependency...&quot; warnings."
-					CommandLine="nmake -f PRJ0041.mak IntDir=$(IntDir)"
-					Outputs="$(IntDir)\alloc.h;$(IntDir)\fp.h;$(IntDir)\m68881.h;$(IntDir)\mem.h;$(IntDir)\pngusr.h;$(IntDir)\strings.h;$(IntDir)\unistd.h;$(IntDir)\unixio.h"/>
-			</FileConfiguration>
-			<FileConfiguration
-				Name="DLL Debug|Win32">
-				<Tool
-					Name="VCCustomBuildTool"
-					Description="Create dummy include files to prevent &quot;Cannot find missing dependency...&quot; warnings."
-					CommandLine="nmake -f PRJ0041.mak IntDir=$(IntDir)"
-					Outputs="$(IntDir)\alloc.h;$(IntDir)\fp.h;$(IntDir)\m68881.h;$(IntDir)\mem.h;$(IntDir)\pngusr.h;$(IntDir)\strings.h;$(IntDir)\unistd.h;$(IntDir)\unixio.h"/>
-			</FileConfiguration>
-			<FileConfiguration
-				Name="DLL VB|Win32">
-				<Tool
-					Name="VCCustomBuildTool"
-					Description="Create dummy include files to prevent &quot;Cannot find missing dependency...&quot; warnings."
-					CommandLine="nmake -f PRJ0041.mak IntDir=$(IntDir)"
-					Outputs="$(IntDir)\alloc.h;$(IntDir)\fp.h;$(IntDir)\m68881.h;$(IntDir)\mem.h;$(IntDir)\pngusr.h;$(IntDir)\strings.h;$(IntDir)\unistd.h;$(IntDir)\unixio.h"/>
-			</FileConfiguration>
-		</File>
-		<File
-			RelativePath="README.txt">
-		</File>
-	</Files>
-	<Globals>
-	</Globals>
-</VisualStudioProject>
diff --git a/extern/libpng/include/projects/visualc71/pngtest.vcproj b/extern/libpng/include/projects/visualc71/pngtest.vcproj
deleted file mode 100644
index ac82ff9b7d..0000000000
--- a/extern/libpng/include/projects/visualc71/pngtest.vcproj
+++ /dev/null
@@ -1,267 +0,0 @@
-<?xml version="1.0" encoding="Windows-1252"?>
-<VisualStudioProject
-	ProjectType="Visual C++"
-	Version="7.10"
-	Name="pngtest"
-	RootNamespace="pngtest">
-	<Platforms>
-		<Platform
-			Name="Win32"/>
-	</Platforms>
-	<Configurations>
-		<Configuration
-			Name="DLL Release|Win32"
-			OutputDirectory=".\Win32_DLL_Release\Test"
-			IntermediateDirectory=".\Win32_DLL_Release\Test"
-			ConfigurationType="1">
-			<Tool
-				Name="VCCLCompilerTool"
-				InlineFunctionExpansion="1"
-				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;NDEBUG;PNG_DLL;PNG_NO_STDIO;_CRT_SECURE_NO_WARNINGS"
-				StringPooling="TRUE"
-				RuntimeLibrary="2"
-				EnableFunctionLevelLinking="TRUE"
-				WarningLevel="3"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"
-				Description="Testing..."
-				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
-$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
-				Outputs="$(IntDir)\pngout.png"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/pngtest.exe"
-				LinkIncremental="1"
-				SubSystem="1"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="DLL Debug|Win32"
-			OutputDirectory=".\Win32_DLL_Debug\Test"
-			IntermediateDirectory=".\Win32_DLL_Debug\Test"
-			ConfigurationType="1">
-			<Tool
-				Name="VCCLCompilerTool"
-				Optimization="0"
-				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;_DEBUG;PNG_DLL;PNG_NO_STDIO;_CRT_SECURE_NO_WARNINGS"
-				BasicRuntimeChecks="3"
-				RuntimeLibrary="3"
-				WarningLevel="3"
-				DebugInformationFormat="4"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"
-				Description="Testing..."
-				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
-$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
-				Outputs="$(IntDir)\pngout.png"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/pngtest.exe"
-				GenerateDebugInformation="TRUE"
-				SubSystem="1"
-				TargetMachine="1"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="DLL VB|Win32"
-			OutputDirectory=".\Win32_DLL_VB\Test"
-			IntermediateDirectory=".\Win32_DLL_VB\Test"
-			ConfigurationType="1">
-			<Tool
-				Name="VCCLCompilerTool"
-				InlineFunctionExpansion="1"
-				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;NDEBUG;PNG_DLL;PNG_NO_STDIO;PNGAPI=__stdcall;PNG_USER_PRIVATEBUILD;_CRT_SECURE_NO_WARNINGS"
-				StringPooling="TRUE"
-				RuntimeLibrary="2"
-				EnableFunctionLevelLinking="TRUE"
-				WarningLevel="2"
-				CallingConvention="2"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"
-				Description="Testing..."
-				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\..\Win32_DLL_Release\ZLib
-$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
-				Outputs="$(IntDir)\pngout.png"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/pngtest.exe"
-				LinkIncremental="1"
-				IgnoreDefaultLibraryNames="$(IntDir)\libpng15b.lib"
-				SubSystem="1"
-				TargetMachine="1"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="LIB Release|Win32"
-			OutputDirectory=".\Win32_LIB_Release\Test"
-			IntermediateDirectory=".\Win32_LIB_Release\Test"
-			ConfigurationType="1">
-			<Tool
-				Name="VCCLCompilerTool"
-				InlineFunctionExpansion="1"
-				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS"
-				StringPooling="TRUE"
-				RuntimeLibrary="0"
-				EnableFunctionLevelLinking="TRUE"
-				WarningLevel="3"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"
-				Description="Testing..."
-				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
-$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
-				Outputs="$(IntDir)\pngout.png"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/pngtest.exe"
-				LinkIncremental="1"
-				SubSystem="1"
-				TargetMachine="1"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="LIB Debug|Win32"
-			OutputDirectory=".\Win32_LIB_Debug\Test"
-			IntermediateDirectory=".\Win32_LIB_Debug\Test"
-			ConfigurationType="1">
-			<Tool
-				Name="VCCLCompilerTool"
-				Optimization="0"
-				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS"
-				BasicRuntimeChecks="3"
-				RuntimeLibrary="1"
-				WarningLevel="3"
-				DebugInformationFormat="4"
-				CompileAs="0"/>
-			<Tool
-				Name="VCCustomBuildTool"
-				Description="Testing..."
-				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
-$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
-				Outputs="$(IntDir)\pngout.png"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/pngtest.exe"
-				GenerateDebugInformation="TRUE"
-				SubSystem="1"
-				TargetMachine="1"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-	</Configurations>
-	<References>
-	</References>
-	<Files>
-		<Filter
-			Name="Source Files"
-			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
-			<File
-				RelativePath="..\..\pngtest.c">
-			</File>
-		</Filter>
-	</Files>
-	<Globals>
-	</Globals>
-</VisualStudioProject>
diff --git a/extern/libpng/include/projects/visualc71/zlib.vcproj b/extern/libpng/include/projects/visualc71/zlib.vcproj
deleted file mode 100644
index 614b869e7f..0000000000
--- a/extern/libpng/include/projects/visualc71/zlib.vcproj
+++ /dev/null
@@ -1,391 +0,0 @@
-<?xml version="1.0" encoding="Windows-1252"?>
-<VisualStudioProject
-	ProjectType="Visual C++"
-	Version="7.10"
-	Name="zlib">
-	<Platforms>
-		<Platform
-			Name="Win32"/>
-	</Platforms>
-	<Configurations>
-		<Configuration
-			Name="DLL Release|Win32"
-			OutputDirectory=".\Win32_DLL_Release\ZLib"
-			IntermediateDirectory=".\Win32_DLL_Release\ZLib"
-			ConfigurationType="2">
-			<Tool
-				Name="VCCLCompilerTool"
-				InlineFunctionExpansion="1"
-				AdditionalIncludeDirectories="..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;NDEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
-				StringPooling="TRUE"
-				RuntimeLibrary="2"
-				EnableFunctionLevelLinking="TRUE"
-				WarningLevel="3"
-				CompileAs="1"/>
-			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)\zlib1.dll"
-				LinkIncremental="1"
-				ModuleDefinitionFile="..\..\..\zlib\win32\zlib.def"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"
-				PreprocessorDefinitions="NDEBUG"
-				Culture="1033"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="DLL Debug|Win32"
-			OutputDirectory=".\Win32_DLL_Debug\ZLib"
-			IntermediateDirectory=".\Win32_DLL_Debug\ZLib"
-			ConfigurationType="2">
-			<Tool
-				Name="VCCLCompilerTool"
-				Optimization="0"
-				AdditionalIncludeDirectories="..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
-				BasicRuntimeChecks="3"
-				RuntimeLibrary="3"
-				WarningLevel="3"
-				DebugInformationFormat="4"
-				CompileAs="1"/>
-			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLinkerTool"
-				OutputFile="$(OutDir)\zlib1d.dll"
-				ModuleDefinitionFile="..\..\..\zlib\win32\zlib.def"
-				GenerateDebugInformation="TRUE"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"
-				PreprocessorDefinitions="_DEBUG"
-				Culture="1033"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="LIB Release|Win32"
-			OutputDirectory=".\Win32_LIB_Release\ZLib"
-			IntermediateDirectory=".\Win32_LIB_Release\ZLib"
-			ConfigurationType="4">
-			<Tool
-				Name="VCCLCompilerTool"
-				InlineFunctionExpansion="1"
-				AdditionalIncludeDirectories="..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;NDEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
-				StringPooling="TRUE"
-				RuntimeLibrary="0"
-				EnableFunctionLevelLinking="TRUE"
-				WarningLevel="3"
-				CompileAs="1"/>
-			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLibrarianTool"
-				OutputFile="$(OutDir)\zlib.lib"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-		<Configuration
-			Name="LIB Debug|Win32"
-			OutputDirectory=".\Win32_LIB_Debug\ZLib"
-			IntermediateDirectory=".\Win32_LIB_Debug\ZLib"
-			ConfigurationType="4">
-			<Tool
-				Name="VCCLCompilerTool"
-				Optimization="0"
-				AdditionalIncludeDirectories="..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
-				BasicRuntimeChecks="3"
-				RuntimeLibrary="1"
-				WarningLevel="3"
-				DebugInformationFormat="4"
-				CompileAs="1"/>
-			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLibrarianTool"
-				OutputFile="$(OutDir)\zlibd.lib"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
-		</Configuration>
-	</Configurations>
-	<References>
-	</References>
-	<Files>
-		<Filter
-			Name="Source Files"
-			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
-			<File
-				RelativePath="..\..\..\zlib\adler32.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\compress.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\crc32.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\deflate.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\gzlib.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\gzclose.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\gzread.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\gzwrite.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\infback.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\inffast.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\inflate.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\inftrees.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\trees.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\uncompr.c">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\win32\zlib.def">
-				<FileConfiguration
-					Name="LIB Release|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Debug|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\zutil.c">
-			</File>
-		</Filter>
-		<Filter
-			Name="Header Files"
-			Filter="h;hpp;hxx;hm;inl">
-			<File
-				RelativePath="..\..\..\zlib\crc32.h">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\deflate.h">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\inffast.h">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\inffixed.h">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\inflate.h">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\inftrees.h">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\trees.h">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\zconf.h">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\zlib.h">
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\zutil.h">
-			</File>
-		</Filter>
-		<Filter
-			Name="Resource Files"
-			Filter="ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe">
-			<File
-				RelativePath="..\..\..\zlib\win32\zlib1.rc">
-				<FileConfiguration
-					Name="LIB Release|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCResourceCompilerTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Debug|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCResourceCompilerTool"/>
-				</FileConfiguration>
-			</File>
-		</Filter>
-		<Filter
-			Name="Assembler Files (Unsupported)"
-			Filter="asm;obj;c;cpp;cxx;h;hpp;hxx">
-			<File
-				RelativePath="..\..\..\zlib\contrib\masmx86\gvmat32.asm">
-				<FileConfiguration
-					Name="DLL Release|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="DLL Debug|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Release|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Debug|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\contrib\masmx86\gvmat32c.c">
-				<FileConfiguration
-					Name="DLL Release|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCLCompilerTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="DLL Debug|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCLCompilerTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Release|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCLCompilerTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Debug|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCLCompilerTool"/>
-				</FileConfiguration>
-			</File>
-			<File
-				RelativePath="..\..\..\zlib\contrib\masmx86\inffas32.asm">
-				<FileConfiguration
-					Name="DLL Release|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="DLL Debug|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Release|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-				<FileConfiguration
-					Name="LIB Debug|Win32"
-					ExcludedFromBuild="TRUE">
-					<Tool
-						Name="VCCustomBuildTool"/>
-				</FileConfiguration>
-			</File>
-		</Filter>
-		<File
-			RelativePath="README.txt">
-		</File>
-	</Files>
-	<Globals>
-	</Globals>
-</VisualStudioProject>
diff --git a/extern/libpng/include/projects/vstudio/libpng/libpng.vcxproj b/extern/libpng/include/projects/vstudio/libpng/libpng.vcxproj
deleted file mode 100644
index c4bf04184e..0000000000
--- a/extern/libpng/include/projects/vstudio/libpng/libpng.vcxproj
+++ /dev/null
@@ -1,233 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup Label="ProjectConfigurations">
-    <ProjectConfiguration Include="Debug Library|Win32">
-      <Configuration>Debug Library</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Debug|Win32">
-      <Configuration>Debug</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release Library|Win32">
-      <Configuration>Release Library</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release|Win32">
-      <Configuration>Release</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-  </ItemGroup>
-  <PropertyGroup Label="Globals">
-    <ProjectGuid>{D6973076-9317-4EF2-A0B8-B7A18AC0713E}</ProjectGuid>
-    <Keyword>Win32Proj</Keyword>
-    <RootNamespace>libpng</RootNamespace>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
-  <Import Project="$(SolutionDir)\zlib.props" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
-    <ConfigurationType>DynamicLibrary</ConfigurationType>
-    <CharacterSet>MultiByte</CharacterSet>
-    <WholeProgramOptimization>true</WholeProgramOptimization>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
-    <ConfigurationType>StaticLibrary</ConfigurationType>
-    <CharacterSet>MultiByte</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
-    <ConfigurationType>DynamicLibrary</ConfigurationType>
-    <WholeProgramOptimization>true</WholeProgramOptimization>
-    <CharacterSet>MultiByte</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
-    <ConfigurationType>StaticLibrary</ConfigurationType>
-    <CharacterSet>MultiByte</CharacterSet>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
-  <ImportGroup Label="ExtensionSettings">
-  </ImportGroup>
-  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
-  </ImportGroup>
-  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
-  </ImportGroup>
-  <PropertyGroup Label="UserMacros" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildBeforeTargets>
-    </CustomBuildBeforeTargets>
-    <TargetName>$(ProjectName)15</TargetName>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildBeforeTargets />
-    <TargetName>$(ProjectName)15</TargetName>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildBeforeTargets>
-    </CustomBuildBeforeTargets>
-    <TargetName>$(ProjectName)15</TargetName>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildBeforeTargets />
-    <TargetName>$(ProjectName)15</TargetName>
-  </PropertyGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <ClCompile>
-      <PrecompiledHeader>Use</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
-      <MinimalRebuild>false</MinimalRebuild>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-      <TreatWChar_tAsBuiltInType>false</TreatWChar_tAsBuiltInType>
-      <PrecompiledHeaderFile>pngpriv.h</PrecompiledHeaderFile>
-      <BrowseInformation>true</BrowseInformation>
-      <CompileAs>CompileAsC</CompileAs>
-      <StringPooling>true</StringPooling>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <Optimization>Disabled</Optimization>
-    </ClCompile>
-    <Link>
-      <SubSystem>Windows</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>zlib.lib</AdditionalDependencies>
-      <Version>15</Version>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-    </Link>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
-    <ClCompile>
-      <PrecompiledHeader>Use</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
-      <MinimalRebuild>false</MinimalRebuild>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Disabled</Optimization>
-      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-      <TreatWChar_tAsBuiltInType>false</TreatWChar_tAsBuiltInType>
-      <PrecompiledHeaderFile>pngpriv.h</PrecompiledHeaderFile>
-      <BrowseInformation>true</BrowseInformation>
-      <CompileAs>CompileAsC</CompileAs>
-      <StringPooling>true</StringPooling>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
-    </ClCompile>
-    <Link>
-      <SubSystem>Windows</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-    </Link>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
-      <PrecompiledHeader>Use</PrecompiledHeader>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;_USRDLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-      <TreatWChar_tAsBuiltInType>false</TreatWChar_tAsBuiltInType>
-      <PrecompiledHeaderFile>pngpriv.h</PrecompiledHeaderFile>
-      <BrowseInformation>true</BrowseInformation>
-      <CompileAs>CompileAsC</CompileAs>
-      <StringPooling>true</StringPooling>
-      <MinimalRebuild>false</MinimalRebuild>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <Optimization>Full</Optimization>
-    </ClCompile>
-    <Link>
-      <SubSystem>Windows</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <EnableCOMDATFolding>true</EnableCOMDATFolding>
-      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>zlib.lib</AdditionalDependencies>
-      <Version>15</Version>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-    </Link>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
-    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
-      <PrecompiledHeader>Use</PrecompiledHeader>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
-      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-      <TreatWChar_tAsBuiltInType>false</TreatWChar_tAsBuiltInType>
-      <PrecompiledHeaderFile>pngpriv.h</PrecompiledHeaderFile>
-      <BrowseInformation>true</BrowseInformation>
-      <CompileAs>CompileAsC</CompileAs>
-      <StringPooling>true</StringPooling>
-      <MinimalRebuild>false</MinimalRebuild>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <Optimization>Full</Optimization>
-      <WholeProgramOptimization>true</WholeProgramOptimization>
-    </ClCompile>
-    <Link>
-      <SubSystem>Windows</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <EnableCOMDATFolding>true</EnableCOMDATFolding>
-      <OptimizeReferences>true</OptimizeReferences>
-    </Link>
-    <Lib>
-      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
-    </Lib>
-  </ItemDefinitionGroup>
-  <ItemGroup>
-    <ClCompile Include="..\..\..\png.c">
-      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">Create</PrecompiledHeader>
-      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">Create</PrecompiledHeader>
-      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">Create</PrecompiledHeader>
-      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">Create</PrecompiledHeader>
-    </ClCompile>
-    <ClCompile Include="..\..\..\pngerror.c" />
-    <ClCompile Include="..\..\..\pngget.c" />
-    <ClCompile Include="..\..\..\pngmem.c" />
-    <ClCompile Include="..\..\..\pngpread.c" />
-    <ClCompile Include="..\..\..\pngread.c" />
-    <ClCompile Include="..\..\..\pngrio.c" />
-    <ClCompile Include="..\..\..\pngrtran.c" />
-    <ClCompile Include="..\..\..\pngrutil.c" />
-    <ClCompile Include="..\..\..\pngset.c" />
-    <ClCompile Include="..\..\..\pngtrans.c" />
-    <ClCompile Include="..\..\..\pngwio.c" />
-    <ClCompile Include="..\..\..\pngwrite.c" />
-    <ClCompile Include="..\..\..\pngwtran.c" />
-    <ClCompile Include="..\..\..\pngwutil.c" />
-  </ItemGroup>
-  <ItemGroup>
-    <ResourceCompile Include="..\..\..\scripts\pngwin.rc">
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">true</ExcludedFromBuild>
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">true</ExcludedFromBuild>
-    </ResourceCompile>
-  </ItemGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
-  <ImportGroup Label="ExtensionTargets">
-  </ImportGroup>
-</Project>
diff --git a/extern/libpng/include/projects/vstudio/pnglibconf/pnglibconf.vcxproj b/extern/libpng/include/projects/vstudio/pnglibconf/pnglibconf.vcxproj
deleted file mode 100644
index 7c691c32d3..0000000000
--- a/extern/libpng/include/projects/vstudio/pnglibconf/pnglibconf.vcxproj
+++ /dev/null
@@ -1,60 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup Label="ProjectConfigurations">
-    <ProjectConfiguration Include="Release|Win32">
-      <Configuration>Release</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-  </ItemGroup>
-  <PropertyGroup Label="Globals">
-    <ProjectGuid>{EB33566E-DA7F-4D28-9077-88C0B7C77E35}</ProjectGuid>
-    <RootNamespace>pnglibconf</RootNamespace>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
-    <ConfigurationType>Application</ConfigurationType>
-    <UseDebugLibraries>false</UseDebugLibraries>
-    <WholeProgramOptimization>true</WholeProgramOptimization>
-    <CharacterSet>MultiByte</CharacterSet>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
-  <ImportGroup Label="ExtensionSettings">
-  </ImportGroup>
-  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-  </ImportGroup>
-  <PropertyGroup Label="UserMacros" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <CustomBuildBeforeTargets>Build</CustomBuildBeforeTargets>
-  </PropertyGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
-      <Optimization>MaxSpeed</Optimization>
-      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-    </ClCompile>
-    <Link>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <EnableCOMDATFolding>true</EnableCOMDATFolding>
-      <OptimizeReferences>true</OptimizeReferences>
-    </Link>
-    <CustomBuildStep>
-      <Command>copy ..\..\..\scripts\pnglibconf.h.prebuilt ..\..\..\pnglibconf.h</Command>
-    </CustomBuildStep>
-    <CustomBuildStep>
-      <Message>Generating pnglibconf.h</Message>
-    </CustomBuildStep>
-    <CustomBuildStep>
-      <Outputs>..\..\..\pnglibconf.h</Outputs>
-    </CustomBuildStep>
-    <CustomBuildStep>
-      <Inputs>..\..\..\scripts\pnglibconf.h.prebuilt</Inputs>
-    </CustomBuildStep>
-  </ItemDefinitionGroup>
-  <ItemGroup>
-  </ItemGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
-  <ImportGroup Label="ExtensionTargets">
-  </ImportGroup>
-</Project>
diff --git a/extern/libpng/include/projects/vstudio/pngtest/pngtest.vcxproj b/extern/libpng/include/projects/vstudio/pngtest/pngtest.vcxproj
deleted file mode 100644
index a03dca565f..0000000000
--- a/extern/libpng/include/projects/vstudio/pngtest/pngtest.vcxproj
+++ /dev/null
@@ -1,219 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup Label="ProjectConfigurations">
-    <ProjectConfiguration Include="Debug Library|Win32">
-      <Configuration>Debug Library</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Debug|Win32">
-      <Configuration>Debug</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release Library|Win32">
-      <Configuration>Release Library</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release|Win32">
-      <Configuration>Release</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-  </ItemGroup>
-  <PropertyGroup Label="Globals">
-    <ProjectGuid>{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}</ProjectGuid>
-    <Keyword>Win32Proj</Keyword>
-    <RootNamespace>pngtest</RootNamespace>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
-  <Import Project="$(SolutionDir)\zlib.props" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
-    <ConfigurationType>Application</ConfigurationType>
-    <CharacterSet>Unicode</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
-    <ConfigurationType>Application</ConfigurationType>
-    <CharacterSet>Unicode</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
-    <ConfigurationType>Application</ConfigurationType>
-    <CharacterSet>Unicode</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
-    <ConfigurationType>Application</ConfigurationType>
-    <CharacterSet>Unicode</CharacterSet>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
-  <ImportGroup Label="ExtensionSettings">
-  </ImportGroup>
-  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
-  </ImportGroup>
-  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
-  </ImportGroup>
-  <PropertyGroup Label="UserMacros" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildAfterTargets />
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildAfterTargets />
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildAfterTargets />
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildAfterTargets />
-  </PropertyGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <ClCompile>
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
-      <MinimalRebuild>false</MinimalRebuild>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Disabled</Optimization>
-      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
-      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <StringPooling>true</StringPooling>
-      <FunctionLevelLinking>false</FunctionLevelLinking>
-      <BrowseInformation>true</BrowseInformation>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-    </ClCompile>
-    <Link>
-      <SubSystem>Console</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng15.lib</AdditionalDependencies>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-    </Link>
-    <CustomBuildStep>
-      <Message>Executing PNG test program</Message>
-      <Command>"$(OutDir)pngtest.exe" ..\..\..\pngtest.png "$(IntDir)pngout.png"</Command>
-      <Outputs>$(IntDir)pngout.png</Outputs>
-      <Inputs>..\..\..\pngtest.png;$(OutDir)pngtest.exe</Inputs>
-    </CustomBuildStep>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
-    <ClCompile>
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
-      <MinimalRebuild>false</MinimalRebuild>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Disabled</Optimization>
-      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
-      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
-      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <StringPooling>true</StringPooling>
-      <FunctionLevelLinking>false</FunctionLevelLinking>
-      <BrowseInformation>true</BrowseInformation>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-    </ClCompile>
-    <Link>
-      <SubSystem>Console</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng15.lib;zlib.lib</AdditionalDependencies>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-    </Link>
-    <CustomBuildStep>
-      <Message>Executing PNG test program</Message>
-      <Command>"$(OutDir)pngtest.exe" ..\..\..\pngtest.png "$(IntDir)pngout.png"</Command>
-      <Outputs>$(IntDir)pngout.png</Outputs>
-      <Inputs>..\..\..\pngtest.png;$(OutDir)pngtest.exe</Inputs>
-    </CustomBuildStep>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Full</Optimization>
-      <FunctionLevelLinking>false</FunctionLevelLinking>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
-      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <StringPooling>true</StringPooling>
-      <MinimalRebuild>false</MinimalRebuild>
-      <BrowseInformation>true</BrowseInformation>
-      <WholeProgramOptimization>true</WholeProgramOptimization>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-    </ClCompile>
-    <Link>
-      <SubSystem>Console</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <EnableCOMDATFolding>true</EnableCOMDATFolding>
-      <OptimizeReferences>true</OptimizeReferences>
-      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
-      <AdditionalDependencies>libpng15.lib</AdditionalDependencies>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-    </Link>
-    <CustomBuildStep>
-      <Message>Executing PNG test program</Message>
-      <Command>"$(OutDir)pngtest.exe" ..\..\..\pngtest.png "$(IntDir)pngout.png"</Command>
-      <Outputs>$(IntDir)pngout.png</Outputs>
-      <Inputs>..\..\..\pngtest.png;$(OutDir)pngtest.exe</Inputs>
-    </CustomBuildStep>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
-    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Full</Optimization>
-      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
-      <FunctionLevelLinking>false</FunctionLevelLinking>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
-      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <StringPooling>true</StringPooling>
-      <MinimalRebuild>false</MinimalRebuild>
-      <BrowseInformation>true</BrowseInformation>
-      <WholeProgramOptimization>true</WholeProgramOptimization>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-    </ClCompile>
-    <Link>
-      <SubSystem>Console</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <EnableCOMDATFolding>true</EnableCOMDATFolding>
-      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng15.lib;zlib.lib</AdditionalDependencies>
-      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-    </Link>
-    <CustomBuildStep>
-      <Message>Executing PNG test program</Message>
-      <Command>$(OutDir)pngtest.exe ..\..\..\pngtest.png $(IntDir)pngout.png</Command>
-      <Command>"$(OutDir)pngtest.exe" ..\..\..\pngtest.png "$(IntDir)pngout.png"</Command>
-      <Outputs>$(IntDir)pngout.png</Outputs>
-      <Inputs>..\..\..\pngtest.png;$(OutDir)pngtest.exe</Inputs>
-    </CustomBuildStep>
-  </ItemDefinitionGroup>
-  <ItemGroup>
-    <ClCompile Include="..\..\..\pngtest.c" />
-  </ItemGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
-  <ImportGroup Label="ExtensionTargets">
-  </ImportGroup>
-</Project>
diff --git a/extern/libpng/include/projects/vstudio/pngvalid/pngvalid.vcxproj b/extern/libpng/include/projects/vstudio/pngvalid/pngvalid.vcxproj
deleted file mode 100644
index 6a0a6e4f31..0000000000
--- a/extern/libpng/include/projects/vstudio/pngvalid/pngvalid.vcxproj
+++ /dev/null
@@ -1,218 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup Label="ProjectConfigurations">
-    <ProjectConfiguration Include="Debug Library|Win32">
-      <Configuration>Debug Library</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Debug|Win32">
-      <Configuration>Debug</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release Library|Win32">
-      <Configuration>Release Library</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release|Win32">
-      <Configuration>Release</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-  </ItemGroup>
-  <PropertyGroup Label="Globals">
-    <ProjectGuid>{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}</ProjectGuid>
-    <Keyword>Win32Proj</Keyword>
-    <RootNamespace>pngvalid</RootNamespace>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
-  <Import Project="$(SolutionDir)\zlib.props" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
-    <ConfigurationType>Application</ConfigurationType>
-    <CharacterSet>Unicode</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
-    <ConfigurationType>Application</ConfigurationType>
-    <CharacterSet>Unicode</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
-    <ConfigurationType>Application</ConfigurationType>
-    <CharacterSet>Unicode</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
-    <ConfigurationType>Application</ConfigurationType>
-    <CharacterSet>Unicode</CharacterSet>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
-  <ImportGroup Label="ExtensionSettings">
-  </ImportGroup>
-  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
-  </ImportGroup>
-  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
-  </ImportGroup>
-  <PropertyGroup Label="UserMacros" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildAfterTargets />
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildAfterTargets />
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildAfterTargets />
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
-    <LinkIncremental>false</LinkIncremental>
-    <CustomBuildAfterTargets />
-  </PropertyGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <ClCompile>
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
-      <MinimalRebuild>false</MinimalRebuild>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Disabled</Optimization>
-      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
-      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <StringPooling>true</StringPooling>
-      <FunctionLevelLinking>false</FunctionLevelLinking>
-      <BrowseInformation>true</BrowseInformation>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-    </ClCompile>
-    <Link>
-      <SubSystem>Console</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng15.lib;zlib.lib</AdditionalDependencies>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-    </Link>
-    <CustomBuildStep>
-      <Message>Executing PNG validation program</Message>
-      <Command>"$(OutDir)pngvalid.exe" --touch "$(IntDir)pngvalid.out"</Command>
-      <Outputs>$(IntDir)pngvalid.out</Outputs>
-      <Inputs>$(OutDir)pngvalid.exe</Inputs>
-    </CustomBuildStep>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
-    <ClCompile>
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
-      <MinimalRebuild>false</MinimalRebuild>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Disabled</Optimization>
-      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
-      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
-      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <StringPooling>true</StringPooling>
-      <FunctionLevelLinking>false</FunctionLevelLinking>
-      <BrowseInformation>true</BrowseInformation>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-    </ClCompile>
-    <Link>
-      <SubSystem>Console</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng15.lib;zlib.lib</AdditionalDependencies>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-    </Link>
-    <CustomBuildStep>
-      <Message>Executing PNG validation program</Message>
-      <Command>"$(OutDir)pngvalid.exe" --touch "$(IntDir)pngvalid.out"</Command>
-      <Outputs>$(IntDir)pngvalid.out</Outputs>
-      <Inputs>$(OutDir)pngvalid.exe</Inputs>
-    </CustomBuildStep>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Full</Optimization>
-      <FunctionLevelLinking>false</FunctionLevelLinking>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
-      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <StringPooling>true</StringPooling>
-      <MinimalRebuild>false</MinimalRebuild>
-      <BrowseInformation>true</BrowseInformation>
-      <WholeProgramOptimization>true</WholeProgramOptimization>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-    </ClCompile>
-    <Link>
-      <SubSystem>Console</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <EnableCOMDATFolding>true</EnableCOMDATFolding>
-      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng15.lib;zlib.lib</AdditionalDependencies>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
-    </Link>
-    <CustomBuildStep>
-      <Message>Executing PNG validation program</Message>
-      <Command>"$(OutDir)pngvalid.exe" --touch "$(IntDir)pngvalid.out"</Command>
-      <Outputs>$(IntDir)pngvalid.out</Outputs>
-      <Inputs>$(OutDir)pngvalid.exe</Inputs>
-    </CustomBuildStep>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
-    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Full</Optimization>
-      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
-      <FunctionLevelLinking>false</FunctionLevelLinking>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
-      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <StringPooling>true</StringPooling>
-      <MinimalRebuild>false</MinimalRebuild>
-      <BrowseInformation>true</BrowseInformation>
-      <WholeProgramOptimization>true</WholeProgramOptimization>
-      <FloatingPointExceptions>false</FloatingPointExceptions>
-    </ClCompile>
-    <Link>
-      <SubSystem>Console</SubSystem>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <EnableCOMDATFolding>true</EnableCOMDATFolding>
-      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng15.lib;zlib.lib</AdditionalDependencies>
-      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
-      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
-    </Link>
-    <CustomBuildStep>
-      <Message>Executing PNG validation program</Message>
-      <Command>"$(OutDir)pngvalid.exe" --touch "$(IntDir)pngvalid.out"</Command>
-      <Outputs>$(IntDir)pngvalid.out</Outputs>
-      <Inputs>$(OutDir)pngvalid.exe</Inputs>
-    </CustomBuildStep>
-  </ItemDefinitionGroup>
-  <ItemGroup>
-    <ClCompile Include="..\..\..\contrib\libtests\pngvalid.c" />
-  </ItemGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
-  <ImportGroup Label="ExtensionTargets">
-  </ImportGroup>
-</Project>
diff --git a/extern/libpng/include/projects/vstudio/readme.txt b/extern/libpng/include/projects/vstudio/readme.txt
deleted file mode 100644
index 938e7dad0b..0000000000
--- a/extern/libpng/include/projects/vstudio/readme.txt
+++ /dev/null
@@ -1,64 +0,0 @@
-
-VisualStudio instructions
-
-libpng version 1.5.10 - March 29, 2012
-
-Copyright (c) 1998-2010 Glenn Randers-Pehrson
-
-This code is released under the libpng license.
-For conditions of distribution and use, see the disclaimer
-and license in png.h
-
-This directory  contains support for building libpng under MicroSoft
-VisualStudio 2010.  It may also work under later versions of VisualStudio.
-You should be familiar with VisualStudio before using this directory.
-
-Initial preparations
-====================
-You must enter some information in zlib.props before attempting to build
-with this 'solution'.  Please read and edit zlib.props first.  You will
-probably not be familiar with the contents of zlib.props - do not worry,
-it is mostly harmless.
-
-This is all you need to do to build the 'release' and 'release library'
-configurations.
-
-Debugging
-=========
-The release configurations default to /Ox optimization.  Full debugging
-information is produced (in the .pdb), but if you encounter a problem the
-optimization may make it difficult to debug.  Simply rebuild with a lower
-optimization level (e.g. /Od.)
-
-Linking your application
-========================
-Normally you should link against the 'release' configuration.  This builds a
-DLL for libpng 1.5 with the default runtime options used by Visual Studio
-2010.  In particular the runtime library is the "MultiThreaded DLL" version.
-If you use Visual Studio defaults to build your application you will have no
-problems.
-
-If you don't use the Visual Studio defaults your application must still be built
-with the default runtime option (/MD).  If, for some reason, it is not then your
-application will crash inside libpng15.dll as soon as libpng tries to read
-from a file handle you pass in.
-
-If you do not want to use the DLL, for example for a very small application,
-the 'release library' configuration may be more appropriate.  This is built
-with a non-standard runtime library - the "MultiThreaded" version.  When you
-build your application it must be compiled with this option (/MT), otherwise
-it will not build (if you are lucky) or crash (if you are not.)
-
-Stop reading here
-=================
-You have enough information to build a working application.
-
-Debug versions have limited support
-===================================
-This solution includes limited support for debug versions of libpng.  You
-do not need these unless your own solution itself uses debug builds (it is
-far more effective to debug on the release builds, there is no point building
-a special debug build.)
-
-The debug build of libpng is minimally supported.  Support for debug builds of
-zlib is also minimal.  You really don't want to do this.
diff --git a/extern/libpng/include/projects/vstudio/vstudio.sln b/extern/libpng/include/projects/vstudio/vstudio.sln
deleted file mode 100644
index c6c50e4431..0000000000
--- a/extern/libpng/include/projects/vstudio/vstudio.sln
+++ /dev/null
@@ -1,87 +0,0 @@
-Microsoft Visual Studio Solution File, Format Version 11.00
-# Visual Studio 2010
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "libpng", "libpng\libpng.vcxproj", "{D6973076-9317-4EF2-A0B8-B7A18AC0713E}"
-	ProjectSection(ProjectDependencies) = postProject
-		{60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
-	EndProjectSection
-EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngtest", "pngtest\pngtest.vcxproj", "{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}"
-	ProjectSection(ProjectDependencies) = postProject
-		{60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E} = {D6973076-9317-4EF2-A0B8-B7A18AC0713E}
-	EndProjectSection
-EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "zlib", "zlib\zlib.vcxproj", "{60F89955-91C6-3A36-8000-13C592FEC2DF}"
-EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngvalid", "pngvalid\pngvalid.vcxproj", "{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}"
-	ProjectSection(ProjectDependencies) = postProject
-		{60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E} = {D6973076-9317-4EF2-A0B8-B7A18AC0713E}
-	EndProjectSection
-EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pnglibconf", "pnglibconf\pnglibconf.vcxproj", "{EB33566E-DA7F-4D28-9077-88C0B7C77E35}"
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug Library|Win32 = Debug Library|Win32
-		Debug|Win32 = Debug|Win32
-		Release Library|Win32 = Release Library|Win32
-		Release|Win32 = Release|Win32
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Debug Library|Win32.Build.0 = Debug Library|Win32
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Debug|Win32.ActiveCfg = Debug|Win32
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Debug|Win32.Build.0 = Debug|Win32
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Release Library|Win32.ActiveCfg = Release Library|Win32
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Release Library|Win32.Build.0 = Release Library|Win32
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Release|Win32.ActiveCfg = Release|Win32
-		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Release|Win32.Build.0 = Release|Win32
-		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
-		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Debug Library|Win32.Build.0 = Debug Library|Win32
-		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Debug|Win32.ActiveCfg = Debug|Win32
-		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Debug|Win32.Build.0 = Debug|Win32
-		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release Library|Win32.ActiveCfg = Release Library|Win32
-		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release Library|Win32.Build.0 = Release Library|Win32
-		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release|Win32.ActiveCfg = Release|Win32
-		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release|Win32.Build.0 = Release|Win32
-		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
-		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug Library|Win32.Build.0 = Debug Library|Win32
-		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug|Win32.ActiveCfg = Debug|Win32
-		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug|Win32.Build.0 = Debug|Win32
-		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Release Library|Win32.ActiveCfg = Release Library|Win32
-		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Release Library|Win32.Build.0 = Release Library|Win32
-		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Release|Win32.ActiveCfg = Release|Win32
-		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Release|Win32.Build.0 = Release|Win32
-		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
-		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug Library|Win32.Build.0 = Debug Library|Win32
-		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug|Win32.ActiveCfg = Debug|Win32
-		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug|Win32.Build.0 = Debug|Win32
-		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Release Library|Win32.ActiveCfg = Release Library|Win32
-		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Release Library|Win32.Build.0 = Release Library|Win32
-		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Release|Win32.ActiveCfg = Release|Win32
-		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Release|Win32.Build.0 = Release|Win32
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Debug Library|Win32.ActiveCfg = Release|Win32
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Debug Library|Win32.Build.0 = Release|Win32
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Debug|Win32.ActiveCfg = Release|Win32
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Debug|Win32.Build.0 = Release|Win32
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release Library|Win32.ActiveCfg = Release|Win32
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release Library|Win32.Build.0 = Release|Win32
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release|Win32.ActiveCfg = Release|Win32
-		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release|Win32.Build.0 = Release|Win32
-		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
-		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug Library|Win32.Build.0 = Debug Library|Win32
-		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug|Win32.ActiveCfg = Debug|Win32
-		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug|Win32.Build.0 = Debug|Win32
-		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release Library|Win32.ActiveCfg = Release Library|Win32
-		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release Library|Win32.Build.0 = Release Library|Win32
-		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release|Win32.ActiveCfg = Release|Win32
-		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release|Win32.Build.0 = Release|Win32
-	EndGlobalSection
-	GlobalSection(SolutionProperties) = preSolution
-		HideSolutionNode = FALSE
-	EndGlobalSection
-EndGlobal
diff --git a/extern/libpng/include/projects/vstudio/zlib.props b/extern/libpng/include/projects/vstudio/zlib.props
deleted file mode 100644
index 0060f127e6..0000000000
--- a/extern/libpng/include/projects/vstudio/zlib.props
+++ /dev/null
@@ -1,37 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
- * zlib.props - location of zlib source
- *
- * libpng version 1.5.10 - March 29, 2012
- *
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
-
- * You must edit this file to record the location of the zlib
- * source code.
- -->
-
-<Project ToolsVersion="4.0"
-   xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <PropertyGroup Label="Globals">
-    <!-- Place the name of the directory containing the source of zlib used for
-	 debugging in this property.
-
-         The directory need only contain the '.c' and '.h' files from the
-	 source.
-
-	 If you use a relative directory name (as below) then it must be
-	 relative to the project directories; these are one level deepers than
-	 the directories containing this file.
-
-	 If the version of zlib you use does not match that used when the
-	 distribution was built you will get warnings from pngtest that the zlib
-	 versions do not match.  The zlib version used in this build is recorded
-	 below:
-     -->
-    <ZLibSrcDir>..\..\..\..\zlib-1.2.5</ZLibSrcDir>
-  </PropertyGroup>
-</Project>
diff --git a/extern/libpng/include/projects/vstudio/zlib/zlib.vcxproj b/extern/libpng/include/projects/vstudio/zlib/zlib.vcxproj
deleted file mode 100644
index d627817969..0000000000
--- a/extern/libpng/include/projects/vstudio/zlib/zlib.vcxproj
+++ /dev/null
@@ -1,174 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup Label="ProjectConfigurations">
-    <ProjectConfiguration Include="Debug Library|Win32">
-      <Configuration>Debug Library</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Debug|Win32">
-      <Configuration>Debug</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release Library|Win32">
-      <Configuration>Release Library</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release|Win32">
-      <Configuration>Release</Configuration>
-      <Platform>Win32</Platform>
-    </ProjectConfiguration>
-  </ItemGroup>
-  <ItemGroup>
-    <ClCompile Include="$(ZLibSrcDir)\adler32.c" />
-    <ClCompile Include="$(ZLibSrcDir)\compress.c" />
-    <ClCompile Include="$(ZLibSrcDir)\crc32.c" />
-    <ClCompile Include="$(ZLibSrcDir)\deflate.c" />
-    <ClCompile Include="$(ZLibSrcDir)\infback.c" />
-    <ClCompile Include="$(ZLibSrcDir)\inffast.c" />
-    <ClCompile Include="$(ZLibSrcDir)\inflate.c" />
-    <ClCompile Include="$(ZLibSrcDir)\inftrees.c" />
-    <ClCompile Include="$(ZLibSrcDir)\trees.c" />
-    <ClCompile Include="$(ZLibSrcDir)\uncompr.c" />
-    <ClCompile Include="$(ZLibSrcDir)\zutil.c" />
-  </ItemGroup>
-  <PropertyGroup Label="Globals">
-    <Keyword>Win32Proj</Keyword>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
-  <Import Project="$(SolutionDir)\zlib.props" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
-    <ConfigurationType>StaticLibrary</ConfigurationType>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
-    <ConfigurationType>StaticLibrary</ConfigurationType>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
-    <ConfigurationType>StaticLibrary</ConfigurationType>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
-    <ConfigurationType>StaticLibrary</ConfigurationType>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
-    <ConfigurationType>StaticLibrary</ConfigurationType>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
-  <ImportGroup Label="ExtensionSettings">
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
-  </ImportGroup>
-  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-  </ImportGroup>
-  <PropertyGroup Label="UserMacros" />
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
-    <LinkIncremental>true</LinkIncremental>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <LinkIncremental>true</LinkIncremental>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
-    <LinkIncremental>true</LinkIncremental>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <LinkIncremental>true</LinkIncremental>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <LinkIncremental>true</LinkIncremental>
-  </PropertyGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
-    <ClCompile>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
-      <WarningLevel>TurnOffAllWarnings</WarningLevel>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Disabled</Optimization>
-      <BrowseInformation>true</BrowseInformation>
-    </ClCompile>
-    <Link>
-      <TargetMachine>MachineX86</TargetMachine>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <SubSystem>Windows</SubSystem>
-    </Link>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <ClCompile>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <WarningLevel>TurnOffAllWarnings</WarningLevel>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Disabled</Optimization>
-      <BrowseInformation>true</BrowseInformation>
-    </ClCompile>
-    <Link>
-      <TargetMachine>MachineX86</TargetMachine>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <SubSystem>Windows</SubSystem>
-    </Link>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
-    <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Full</Optimization>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <WholeProgramOptimization>true</WholeProgramOptimization>
-      <BufferSecurityCheck>false</BufferSecurityCheck>
-      <BrowseInformation>true</BrowseInformation>
-      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <TreatWarningAsError>true</TreatWarningAsError>
-      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
-    </ClCompile>
-    <Link>
-      <TargetMachine>MachineX86</TargetMachine>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <SubSystem>Windows</SubSystem>
-    </Link>
-    <Lib>
-      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
-    </Lib>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <Optimization>Full</Optimization>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-      <WholeProgramOptimization>true</WholeProgramOptimization>
-      <BufferSecurityCheck>false</BufferSecurityCheck>
-      <BrowseInformation>true</BrowseInformation>
-      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <TreatWarningAsError>true</TreatWarningAsError>
-    </ClCompile>
-    <Link>
-      <TargetMachine>MachineX86</TargetMachine>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <SubSystem>Windows</SubSystem>
-    </Link>
-    <Lib>
-      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
-    </Lib>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <ClCompile>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <WarningLevel>Level3</WarningLevel>
-      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-    </ClCompile>
-    <Link>
-      <TargetMachine>MachineX86</TargetMachine>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <SubSystem>Windows</SubSystem>
-      <EnableCOMDATFolding>true</EnableCOMDATFolding>
-      <OptimizeReferences>true</OptimizeReferences>
-    </Link>
-  </ItemDefinitionGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
-  <ImportGroup Label="ExtensionTargets">
-  </ImportGroup>
-</Project>
diff --git a/extern/libpng/include/scripts/README.txt b/extern/libpng/include/scripts/README.txt
deleted file mode 100644
index 46611a5719..0000000000
--- a/extern/libpng/include/scripts/README.txt
+++ /dev/null
@@ -1,76 +0,0 @@
-
-Makefiles for  libpng version 1.5.10 - March 29, 2012
-
-pnglibconf.h.prebuilt       =>  Stores configuration settings
- makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng15.so.15.1.5.10)
- makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
- makefile.knr      =>  Archaic UNIX Makefile that converts files with
-                       ansi2knr (Requires ansi2knr.c from
-                       ftp://ftp.cs.wisc.edu/ghost)
- makefile.acorn    =>  Acorn makefile
- makefile.aix      =>  AIX/gcc makefile
- makefile.amiga    =>  Amiga makefile
- makefile.atari    =>  Atari makefile
- makefile.bc32     =>  32-bit Borland C++ (all modules compiled in C mode)
- makefile.beos     =>  beos makefile
- makefile.bor      =>  Borland makefile (uses bcc)
- makefile.cegcc    =>  minge32ce for Windows CE makefile
- makefile.darwin   =>  Darwin makefile, can use on MacosX
- makefile.dec      =>  DEC Alpha UNIX makefile
- makefile.dj2      =>  DJGPP 2 makefile
- makefile.elf      =>  Linux/ELF makefile symbol versioning,
-                       (gcc, creates libpng15.so.15.1.5.10)
- makefile.freebsd  =>  FreeBSD makefile
- makefile.gcc      =>  Generic gcc makefile
- makefile.hpgcc    =>  HPUX makefile using gcc
- makefile.hpux     =>  HPUX (10.20 and 11.00) makefile
- makefile.hp64     =>  HPUX (10.20 and 11.00) makefile, 64-bit
- makefile.ibmc     =>  IBM C/C++ version 3.x for Win32 and OS/2 (static)
- makefile.intel    =>  Intel C/C++ version 4.0 and later
- makefile.mips     =>  MIPS makefile
- makefile.msc      =>  Microsoft C makefile
- makefile.netbsd   =>  NetBSD/cc makefile, makes libpng.so.
- makefile.openbsd  =>  OpenBSD makefile
- makefile.os2      =>  OS/2 Makefile (gcc and emx, requires libpng.def)
- makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
- makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng15.so.15.1.5.10)
- makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
- makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng15.so.15.1.5.10)
- makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng15.so.15.1.5.10)
- makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
- makefile.sunos    =>  Sun makefile
- makefile.32sunu   =>  Sun Ultra 32-bit makefile
- makefile.64sunu   =>  Sun Ultra 64-bit makefile
- makefile.tc3      =>  Turbo C 3.0 makefile
- makefile.vcwin32  =>  makefile for Microsoft Visual C++ 4.0 and later
- makevms.com       =>  VMS build script
- smakefile.ppc     =>  AMIGA smakefile for SAS C V6.58/7.00 PPC compiler
-                       (Requires SCOPTIONS, copied from scripts/SCOPTIONS.ppc)
-
-Other supporting scripts:
- README.txt        =>  This file
- descrip.mms       =>  VMS makefile for MMS or MMK
- libpng-config-body.in => used by several makefiles to create libpng-config
- libpng-config-head.in => used by several makefiles to create libpng-config
- libpng.pc.in      =>  Used by several makefiles to create libpng.pc
- pngwin.rc         =>  Used by the visualc71 project.
- pngwin.def        =>  Used by makefile.os2
- pngwin.dfn        =>  Used to maintain pngwin.def
- SCOPTIONS.ppc     =>  Used with smakefile.ppc
-
-checksym.awk       =>  Used for maintaining pnglibconf.h
-def.dfn            =>  Used for maintaining pnglibconf.h
-options.awk        =>  Used for maintaining pnglibconf.h
-pnglibconf.dfa     =>  Used for maintaining pnglibconf.h
-pnglibconf.mak     =>  Used for maintaining pnglibconf.h
-sym.dfn            =>  Used for symbol versioning
-symbols.def        =>  Used for symbol versioning
-symbols.dfn        =>  Used for symbol versioning
-vers.dfn           =>  Used for symbol versioning
-
-
-Further information can be found in comments in the individual makefiles.
diff --git a/extern/libpng/include/scripts/SCOPTIONS.ppc b/extern/libpng/include/scripts/SCOPTIONS.ppc
deleted file mode 100644
index 2c3503e9eb..0000000000
--- a/extern/libpng/include/scripts/SCOPTIONS.ppc
+++ /dev/null
@@ -1,7 +0,0 @@
-OPTIMIZE
-OPTPEEP
-OPTTIME
-OPTSCHED
-AUTOREGISTER
-PARMS=REGISTERS
-INCLUDEDIR=hlp:ppc/include
diff --git a/extern/libpng/include/scripts/checksym.awk b/extern/libpng/include/scripts/checksym.awk
deleted file mode 100755
index ba4c99b564..0000000000
--- a/extern/libpng/include/scripts/checksym.awk
+++ /dev/null
@@ -1,161 +0,0 @@
-#!/bin/awk -f
-# Check a list of symbols against the master definition
-# (official) list.  Arguments:
-#
-# awk -f checksym.awk official-def list-to-check
-#
-# Output is a file in the current directory called 'symbols.new',
-# stdout holds error messages.  Error code indicates success or
-# failure.
-#
-# NOTE: this is a pure, old fashioned, awk script.  It will
-# work with any awk
-
-BEGIN{
-   err=0
-   master=""        # master file
-   official[1] = "" # defined symbols from master file
-   symbol[1] = ""   # defined symbols from png.h
-   removed[1] = ""  # removed symbols from png.h
-   lasto = 0        # last ordinal value from png.h
-   mastero = 0      # highest ordinal in master file
-   symbolo = 0      # highest ordinal in png.h
-   missing = "error"# log an error on missing symbols
-}
-
-# Read existing definitions from the master file (the first
-# file on the command line.)  This must be a def file and it
-# has definition lines (others are ignored) of the form:
-#
-#   symbol @ordinal
-#
-master == "" {
-   master = FILENAME
-}
-FILENAME==master && NF==2 && $2~/^@/ && $1!~/^;/ {
-   o=0+substr($2,2)
-   if (o > 0) {
-      if (official[o] == "") {
-         official[o] = $1
-         if (o > mastero) mastero = o
-         next
-      } else
-         print master ": duplicated symbol:", official[o] ":", $0
-   } else
-      print master ": bad export line format:", $0
-   err = 1
-}
-FILENAME==master && $1==";missing" && NF==2{
-   # This allows the master file to control how missing symbols
-   # are handled; symbols that aren't in either the master or
-   # the new file.  Valid values are 'ignore', 'warning' and
-   # 'error'
-   missing = $2
-}
-FILENAME==master {
-   next
-}
-
-# Read new definitions, these are free form but the lines must
-# just be symbol definitions.  Lines will be commented out for
-# 'removed' symbols, introduced in png.h using PNG_REMOVED rather
-# than PNG_EXPORT.  Use symbols.dfn or pngwin.dfn to generate the
-# input file.
-#
-#  symbol @ordinal   # two fields, exported symbol
-#  ; symbol @ordinal # three fields, removed symbol
-#  ; @ordinal        # two fields, the last ordinal
-NF==2 && $1 == ";" && $2 ~ /^@[1-9][0-9]*$/ { # last ordinal
-   o=0+substr($2,2)
-   if (lasto == 0 || lasto == o)
-      lasto=o
-   else {
-      print "png.h: duplicated last ordinal:", lasto, o
-      err = 1
-   }
-   next
-}
-NF==3 && $1 == ";" && $3 ~ /^@[1-9][0-9]*$/ { # removed symbol
-   o=0+substr($3,2)
-   if (removed[o] == "" || removed[o] == $2) {
-      removed[o] = $2
-      if (o > symbolo) symbolo = o
-   } else {
-      print "png.h: duplicated removed symbol", o ": '" removed[o] "' != '" $2 "'"
-      err = 1
-   }
-   next
-}
-NF==2 && $2 ~ /^@[1-9][0-9]*$/ { # exported symbol
-   o=0+substr($2,2)
-   if (symbol[o] == "" || symbol[o] == $1) {
-      symbol[o] = $1
-      if (o > symbolo) symbolo = o
-   } else {
-      print "png.h: duplicated symbol", o ": '" symbol[o] "' != '" $1 "'"
-      err = 1
-   }
-}
-{
-   next # skip all other lines
-}
-
-# At the end check for symbols marked as both duplicated and removed
-END{
-   if (symbolo > lasto) {
-      print "highest symbol ordinal in png.h,", symbolo ", exceeds last ordinal from png.h", lasto
-      err = 1
-   }
-   if (mastero > lasto) {
-      print "highest symbol ordinal in", master ",", mastero ", exceeds last ordinal from png.h", lasto
-      err = 1
-   }
-   unexported=0
-   for (o=1; o<=lasto; ++o) {
-      if (symbol[o] == "" && removed[o] == "") {
-         if (unexported == 0) unexported = o
-         if (official[o] == "") {
-            # missing in export list too, so ok
-            if (o < lasto) continue
-         }
-      }
-      if (unexported != 0) {
-         # Symbols in the .def but not in the new file are errors, but
-         # the 'unexported' symbols aren't in either.  By default this
-         # is an error too (see the setting of 'missing' at the start),
-         # but this can be reset on the command line or by stuff in the
-         # file - see the comments above.
-         if (missing != "ignore") {
-            if (o-1 > unexported)
-               print "png.h:", missing ": missing symbols:", unexported "-" o-1
-            else
-               print "png.h:", missing ": missing symbol:", unexported
-            if (missing != "warning")
-               err = 1
-         }
-         unexported = 0
-      }
-      if (symbol[o] != "" && removed[o] != "") {
-         print "png.h: symbol", o, "both exported as '" symbol[o] "' and removed as '" removed[o] "'"
-         err = 1
-      } else if (symbol[o] != official[o]) {
-         # either the symbol is missing somewhere or it changed
-         err = 1
-         if (symbol[o] == "")
-            print "png.h: symbol", o, "is exported as '" official[o] "' in", master
-         else if (official[o] == "")
-            print "png.h: exported symbol", o, "'" symbol[o] "' not present in", master
-         else
-            print "png.h: exported symbol", o, "'" symbol[o] "' exists as '" official[o] "' in", master
-      }
-
-      # Finally generate symbols.new
-      if (symbol[o] != "")
-         print " " symbol[o], "@" o > "symbols.new"
-   }
-
-   if (err != 0) {
-      print "*** A new list is in symbols.new ***"
-      exit 1
-   }
-}
diff --git a/extern/libpng/include/scripts/chkfmt b/extern/libpng/include/scripts/chkfmt
deleted file mode 100755
index 9da6475fd4..0000000000
--- a/extern/libpng/include/scripts/chkfmt
+++ /dev/null
@@ -1,137 +0,0 @@
-#!/bin/sh
-#
-# Check the format of the source files in the current directory - checks for a
-# line length of 80 characters max and no tab characters.
-#
-# Optionally arguments are files or directories to check.
-#
-# -v: output the long lines (makes fixing them easier)
-# -e: spawn an editor for each file that needs a change ($EDITOR must be
-#     defined).  When using -e the script MUST be run from an interactive
-#     command line.
-verbose=
-edit=
-vers=
-test "$1" = "-v" && {
-   shift
-   verbose=yes
-}
-test "$1" = "-e" && {
-   shift
-   if test -n "$EDITOR"
-   then
-      edit=yes
-
-      # Copy the standard streams for the editor
-      exec 3>&0 4>&1 5>&2
-   else
-      echo "chkfmt -e: EDITOR must be defined" >&2
-      exit 1
-   fi
-}
-
-# Function to edit a single file - if the file isn't changed ask the user
-# whether or not to continue.  This stuff only works if the script is run from
-# the command line (otherwise, don't specify -e or you will be sorry).
-doed(){
-   cp "$file" "$file".orig
-   "$EDITOR" "$file" 0>&3 1>&4 2>&5 3>&- 4>&- 5>&- || exit 1
-   if cmp -s "$file".orig "$file"
-   then
-      rm "$file".orig
-      echo -n "$file: file not changed, type anything to continue: " >&5
-      read ans 0>&3
-      test -n "$ans" || return 1
-   fi
-   return 0
-}
-
-# In beta versions the version string which appears in files can be a little
-# long and cause spuriously overlong lines.  To avoid this subtitute the version
-# string with a 'standard' version a.b.cc before checking for long lines.
-if test -r png.h
-then
-   vers="`sed -n -e \
-   's/^#define PNG_LIBPNG_VER_STRING .\([0-9]\.[0-9]\.[0-9][0-9a-z]*\).$/\1/p' \
-   png.h`"
-   echo "chkfmt: checking version $vers"
-fi
-if test -z "$vers"
-then
-   echo "chkfmt: png.h not found, ignoring version number" >&2
-fi
-
-test -n "$1" || set -- .
-find "$@" \( -type d \( -name '.git' -o -name '.libs' -o -name 'projects' \) \
-   -prune \) -o \( -type f \
-   ! -name '*.[oa]' ! -name '*.l[oa]' !  -name '*.png' ! -name '*.out' \
-   ! -name '*.jpg' ! -name '*.patch' ! -name '*.obj' ! -name '*.exe' \
-   ! -name '*.com' ! -name '*.tar.*' ! -name '*.zip' ! -name '*.ico' \
-   ! -name '*.res' ! -name '*.rc' ! -name '*.mms' ! -name '*.rej' \
-   ! -name '*.dsp' ! -name '*.orig' ! -name '*.dfn' ! -name '*.swp' \
-   ! -name '~*' ! -name '*.3' \
-   ! -name 'missing' ! -name 'mkinstalldirs' ! -name 'depcomp' \
-   ! -name 'aclocal.m4' ! -name 'install-sh' ! -name 'Makefile.in' \
-   ! -name 'ltmain.sh' ! -name 'config*' -print \) | {
-   st=0
-   while read file
-   do
-      case "$file" in
-      *.mak|*[Mm]akefile.*|*[Mm]akefile)
-         # Makefiles require tabs, dependency lines can be this long.
-         check_tabs=
-         line_length=100;;
-      *.awk)
-         # Includes literal tabs
-         check_tabs=
-         # The following is arbitrary
-         line_length=132;;
-      *contrib/*/*.[ch])
-         check_tabs=yes
-         line_length=96;;
-      *)
-         check_tabs=yes
-         line_length=80;;
-      esac
-
-      # Note that vers can only contain 0-9, . and a-z
-      if test -n "$vers"
-      then
-         sed -e "s/$vers/a.b.cc/g" "$file" >"$file".$$
-      else
-         cp "$file" "$file".$$
-      fi
-      splt="`fold -$line_length "$file".$$ | diff -c "$file".$$ -`"
-      rm "$file".$$
-
-      if test -n "$splt"
-      then
-         echo "$file: lines too long"
-         st=1
-         if test -n "$EDITOR" -a -n "$edit"
-         then
-            doed "$file" || exit 1
-         elif test -n "$verbose"
-         then
-            echo "$splt"
-         fi
-      fi
-      if test -n "$check_tabs"
-      then
-         tab="`tr -c -d '\t' <"$file"`"
-         if test -n "$tab"
-         then
-            echo "$file: file contains tab characters"
-            st=1
-            if test -n "$EDITOR" -a -n "$edit"
-            then
-               doed "$file" || exit 1
-            elif test -n "$verbose"
-            then
-               echo "$splt"
-            fi
-         fi
-      fi
-   done
-   exit $st
-}
diff --git a/extern/libpng/include/scripts/def.dfn b/extern/libpng/include/scripts/def.dfn
deleted file mode 100644
index f9918631de..0000000000
--- a/extern/libpng/include/scripts/def.dfn
+++ /dev/null
@@ -1,38 +0,0 @@
-/* def.dfn - define format of libpng.def
- *
- * Last changed in libpng version 1.5.7 [December 15, 2011]
- * Copyright (c) 2010-2011 Glenn Randers-Pehrson
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-/* These macros exist to make the header and trailer shorter below: */
-#define S PNG_DEFN_MAGIC
-#define E PNG_DEFN_END
-
-/* Write the export file header: */
-S-;---------------------------------------------------------------E
-S-; LIBPNG module definition file for OS/2-E
-S-;---------------------------------------------------------------E
-S--E
-S-; If you give the library an explicit name one or other files-E
-S-; may need modifying to support the new name on one or more-E
-S-; systems.-E
-S-LIBRARY-E
-S-OS2 DESCRIPTION "PNG image compression library"-E
-S-OS2 CODE PRELOAD MOVEABLE DISCARDABLE-E
-S--E
-S-EXPORTS-E
-S-;Version 1.5.0beta58-E
-
-/* NOTE: PNG_JOIN is interpreted by the calling script as a signal to
- * join the two things on either side, so we can do symbol
- * substitution within the name, regular C ## joins the pp-tokens,
- * not their final values.
- */
-#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
-	PNG_DEFN_MAGIC- SYMBOL_PREFIX PNG_JOIN name-PNG_DEFN_END
-
-#include "../png.h"
diff --git a/extern/libpng/include/scripts/descrip.mms b/extern/libpng/include/scripts/descrip.mms
deleted file mode 100644
index 99ea1abccd..0000000000
--- a/extern/libpng/include/scripts/descrip.mms
+++ /dev/null
@@ -1,52 +0,0 @@
-
-cc_defs = /inc=$(ZLIBSRC)
-c_deb =
-
-.ifdef __DECC__
-pref = /prefix=all
-.endif
-
-
-
-OBJS = png.obj, pngset.obj, pngget.obj, pngrutil.obj, pngtrans.obj,\
-	pngwutil.obj, pngread.obj, pngmem.obj, pngwrite.obj, pngrtran.obj,\
-	pngwtran.obj, pngrio.obj, pngwio.obj, pngerror.obj, pngpread.obj
-
-
-CFLAGS= $(C_DEB) $(CC_DEFS) $(PREF)
-
-all : pngtest.exe libpng.olb
-		@ write sys$output " pngtest available"
-
-libpng.olb : libpng.olb($(OBJS))
-	@ write sys$output " Libpng available"
-
-
-pngtest.exe : pngtest.obj libpng.olb
-              link pngtest,libpng.olb/lib,$(ZLIBSRC)libz.olb/lib
-
-test : pngtest.exe
-   run pngtest
-
-clean :
-	delete *.obj;*,*.exe;
-
-
-# Other dependencies.
-png.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngpread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngset.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngget.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngrtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngrutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngerror.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngmem.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngrio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngwio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngtrans.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngwrite.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngwtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngwutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-
-pngtest.obj : png.h, pngconf.h
diff --git a/extern/libpng/include/scripts/libpng-config-body.in b/extern/libpng/include/scripts/libpng-config-body.in
deleted file mode 100755
index b466432d54..0000000000
--- a/extern/libpng/include/scripts/libpng-config-body.in
+++ /dev/null
@@ -1,96 +0,0 @@
-
-usage()
-{
-    cat <<EOF
-Usage: libpng-config [OPTION] ...
-
-Known values for OPTION are:
-
-  --prefix        print libpng prefix
-  --libdir        print path to directory containing library
-  --libs          print library linking information
-  --ccopts        print compiler options
-  --cppflags      print pre-processor flags
-  --cflags        print preprocessor flags, I_opts, and compiler options
-  --I_opts        print "-I" include options
-  --L_opts        print linker "-L" flags for dynamic linking
-  --R_opts        print dynamic linker "-R" or "-rpath" flags
-  --ldopts        print linker options
-  --ldflags       print linker flags (ldopts, L_opts, R_opts, and libs)
-  --static        revise subsequent outputs for static linking
-  --help          print this help and exit
-  --version       print version information
-EOF
-
-    exit $1
-}
-
-if test $# -eq 0; then
-    usage 1
-fi
-
-while test $# -gt 0; do
-    case "$1" in
-
-    --prefix)
-        echo ${prefix}
-        ;;
-
-    --version)
-        echo ${version}
-        exit 0
-        ;;
-
-    --help)
-        usage 0
-        ;;
-
-    --ccopts)
-        echo ${ccopts}
-        ;;
-
-    --cppflags)
-        echo ${cppflags}
-        ;;
-
-    --cflags)
-        echo ${I_opts} ${cppflags} ${ccopts}
-        ;;
-
-    --libdir)
-        echo ${libdir}
-        ;;
-
-    --libs)
-        echo ${libs}
-        ;;
-
-    --I_opts)
-        echo ${I_opts}
-        ;;
-
-    --L_opts)
-        echo ${L_opts}
-        ;;
-
-    --R_opts)
-        echo ${R_opts}
-        ;;
-
-    --ldflags)
-        echo ${ldflags} ${L_opts} ${R_opts} ${libs}
-        ;;
-
-    --static)
-        R_opts=""
-        ;;
-
-    *)
-        usage
-        exit 1
-        ;;
-    esac
-    shift
-done
-
-exit 0
diff --git a/extern/libpng/include/scripts/libpng-config-head.in b/extern/libpng/include/scripts/libpng-config-head.in
deleted file mode 100755
index 4dda9cda90..0000000000
--- a/extern/libpng/include/scripts/libpng-config-head.in
+++ /dev/null
@@ -1,24 +0,0 @@
-#! /bin/sh
-
-# libpng-config
-# provides configuration info for libpng.
-
-# Copyright (C) 2002 Glenn Randers-Pehrson
-
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Modeled after libxml-config.
-
-version=1.5.10
-prefix=""
-libdir=""
-libs=""
-I_opts=""
-L_opts=""
-R_opts=""
-cppflags=""
-ccopts=""
-ldopts=""
-
diff --git a/extern/libpng/include/scripts/libpng.pc.in b/extern/libpng/include/scripts/libpng.pc.in
deleted file mode 100644
index f96298ca8b..0000000000
--- a/extern/libpng/include/scripts/libpng.pc.in
+++ /dev/null
@@ -1,10 +0,0 @@
-prefix=@prefix@
-exec_prefix=@exec_prefix@
-libdir=@libdir@
-includedir=@includedir@/libpng15
-
-Name: libpng
-Description: Loads and saves PNG files
-Version: 1.5.10
-Libs: -L${libdir} -lpng15
-Cflags: -I${includedir}
diff --git a/extern/libpng/include/scripts/makefile.32sunu b/extern/libpng/include/scripts/makefile.32sunu
deleted file mode 100644
index b5e5a33a06..0000000000
--- a/extern/libpng/include/scripts/makefile.32sunu
+++ /dev/null
@@ -1,241 +0,0 @@
-# makefile for libpng on Solaris 2.x with cc
-# Contributed by William L. Sebok, based on makefile.linux
-# Copyright (C) 2002, 2006, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1998 Greg Roelofs
-# Copyright (C) 1996, 1997 Andreas Dilger
-
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME=libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-CC=cc
-AR_RC=ar rc
-MKDIR_P=mkdir -p
-LN_SF=ln -f -s
-RANLIB=echo
-RM_F=/bin/rm -f
-
-SUN_CC_FLAGS=-fast -xtarget=ultra
-SUN_LD_FLAGS=-fast -xtarget=ultra
-
-# where make install puts libpng.a, libpng15.so and libpng15/png.h
-prefix=/a
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-# Changing these to ../zlib poses a security risk.  If you want
-# to have zlib in an adjacent directory, specify the full path instead of "..".
-#ZLIBLIB=../zlib
-#ZLIBINC=../zlib
-
-ZLIBLIB=/usr/lib
-ZLIBINC=/usr/include
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) $(SUN_CC_FLAGS) \
-	# $(WARNMORE) -g -DPNG_DEBUG=5
-LDFLAGS=$(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) libpng.a -lz -lm
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -KPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-include scripts/pnglibconf.mak
-DELETE = $(RM_F)
-DFNFLAGS = $(DEFS) $(CPPFLAGS)
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo libdir=\"$(LIBPATH)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo ccopts=\"-xtarget=ultra\"; \
-	echo ldopts=\"-xtarget=ultra\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	@case "`type ld`" in *ucb*) \
-	echo; \
-	echo '## WARNING:'; \
-	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
-	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
-	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
-	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
-	echo '## at all.  If it is, things are likely to break because of'; \
-	echo '## the libucb dependency that is created.'; \
-	echo; \
-	;; \
-	esac
-	$(LD) -G -L$(ZLIBLIB) -R$(ZLIBLIB) -h $(LIBSOMAJ) \
-	 -o $(LIBSOMAJ) $(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) $(SUN_CC_FLAGS) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtestd -L$(DL) -R$(DL) `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) $(SUN_CC_FLAGS) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
-	libpng-config $(LIBSO) $(LIBSOMAJ)* \
-	libpng.pc
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.64sunu b/extern/libpng/include/scripts/makefile.64sunu
deleted file mode 100644
index a0331d670e..0000000000
--- a/extern/libpng/include/scripts/makefile.64sunu
+++ /dev/null
@@ -1,241 +0,0 @@
-# makefile for libpng on Solaris 2.x with cc
-# Contributed by William L. Sebok, based on makefile.linux
-# Copyright (C) 2002, 2006, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1998 Greg Roelofs
-# Copyright (C) 1996, 1997 Andreas Dilger
-
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME=libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-CC=cc
-AR_RC=ar rc
-MKDIR_P=mkdir -p
-LN_SF=ln -f -s
-RANLIB=echo
-RM_F=/bin/rm -f
-
-SUN_CC_FLAGS=-fast -xtarget=ultra -xarch=v9
-SUN_LD_FLAGS=-fast -xtarget=ultra -xarch=v9
-
-# where make install puts libpng.a, libpng15.so and libpng15/png.h
-prefix=/a
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-# Changing these to ../zlib poses a security risk.  If you want
-# to have zlib in an adjacent directory, specify the full path instead of "..".
-#ZLIBLIB=../zlib
-#ZLIBINC=../zlib
-
-ZLIBLIB=/usr/lib
-ZLIBINC=/usr/include
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) $(SUN_CC_FLAGS) \
-	# $(WARNMORE) -g -DPNG_DEBUG=5
-LDFLAGS=-L. -R. $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng15 -lz -lm
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -KPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-include scripts/pnglibconf.mak
-DELETE = $(RM_F)
-DFNFLAGS = $(DEFS) $(CPPFLAGS)
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo libdir=\"$(LIBPATH)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo ccopts=\"-xtarget=ultra -xarch=v9\"; \
-	echo ldopts=\"-xtarget=ultra -xarch=v9\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	@case "`type ld`" in *ucb*) \
-	echo; \
-	echo '## WARNING:'; \
-	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
-	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
-	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
-	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
-	echo '## at all.  If it is, things are likely to break because of'; \
-	echo '## the libucb dependency that is created.'; \
-	echo; \
-	;; \
-	esac
-	$(LD) -G -L$(ZLIBLIB) -R$(ZLIBLIB) -h $(LIBSOMAJ) \
-	 -o $(LIBSOMAJ) $(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) $(SUN_CC_FLAGS) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtestd -L$(DL) -R$(DL) `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) $(SUN_CC_FLAGS) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
-	libpng-config $(LIBSO) $(LIBSOMAJ)* \
-	libpng.pc
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.acorn b/extern/libpng/include/scripts/makefile.acorn
deleted file mode 100644
index 00b8fb5b35..0000000000
--- a/extern/libpng/include/scripts/makefile.acorn
+++ /dev/null
@@ -1,57 +0,0 @@
-# Project:   libpng
-
-
-# Toolflags:
-CCflags = -c -depend !Depend -IC:,Zlib: -g -throwback  -DRISCOS  -fnah
-C++flags = -c -depend !Depend -IC: -throwback
-Linkflags = -aif -c++ -o $@
-ObjAsmflags = -throwback -NoCache -depend !Depend
-CMHGflags =
-LibFileflags = -c -l -o $@
-Squeezeflags = -o $@
-
-# Final targets:
-@.libpng-lib:   @.o.png @.o.pngerror @.o.pngrio @.o.pngwio @.o.pngmem \
-	@.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngrtran \
-	@.o.pngrutil @.o.pngtrans @.o.pngwrite @.o.pngwtran @.o.pngwutil
-	LibFile $(LibFileflags) @.o.png @.o.pngerror @.o.pngrio @.o.pngrtran \
-	@.o.pngmem @.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngwio \
-	@.o.pngrutil @.o.pngtrans  @.o.pngwrite @.o.pngwtran @.o.pngwutil
-@.mm-libpng-lib:   @.mm.png @.mm.pngerror @.mm.pngrio @.mm.pngwio @.mm.pngmem \
-	@.mm.pngpread @.mm.pngset @.mm.pngget @.mm.pngread @.mm.pngrtran \
-	@.mm.pngrutil @.mm.pngtrans @.mm.pngwrite @.mm.pngwtran @.mm.pngwutil
-	LibFile $(LibFileflags) @.mm.png @.mm.pngerror @.mm.pngrio \
-	@.mm.pngwio @.mm.pngmem @.mm.pngpread @.mm.pngset @.mm.pngget \
-	@.mm.pngread @.mm.pngrtran @.mm.pngrutil @.mm.pngtrans @.mm.pngwrite \
-	@.mm.pngwtran @.mm.pngwutil
-
-
-# User-editable dependencies:
-# (C) Copyright 1997 Tom Tanner
-Test: @.pngtest
-	<Prefix$Dir>.pngtest
-	@remove <Prefix$Dir>.pngtest
-
-#It would be nice if you could stop "make" listing from here on!
-@.pngtest:   @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib
-	Link $(Linkflags) @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib
-
-.SUFFIXES: .o .mm .c
-
-.c.mm:
-	MemCheck.CC cc $(ccflags) -o $@ LibPng:$<
-.c.o:
-	cc $(ccflags) -o $@ $<
-
-# See scripts.mak.libpngconf for how to generate this:
-@.h.libpngconf: @.scripts.h.libpngconf
-	copy @.scripts.h.libpngconf $@
-
-# Static dependencies:
-@.o.png @.o.pngerror @.o.pngrio @.o.pngwio @.o.pngmem \
-@.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngrtran \
-@.o.pngrutil @.o.pngtrans @.o.pngwrite @.o.pngwtran @.o.pngwutil \
-@.o.pngtest: @.h.libpngconf
-
-
-# Dynamic dependencies:
diff --git a/extern/libpng/include/scripts/makefile.aix b/extern/libpng/include/scripts/makefile.aix
deleted file mode 100644
index bb4c40d4b0..0000000000
--- a/extern/libpng/include/scripts/makefile.aix
+++ /dev/null
@@ -1,121 +0,0 @@
-# makefile for libpng using gcc (generic, static library)
-# Copyright (C) 2002, 2006-2009 Glenn Randers-Pehrson
-# Copyright (C) 2000 Cosmin Truta
-# Copyright (C) 2000 Marc O. Gloor (AIX support added, from makefile.gcc)
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Location of the zlib library and include files
-ZLIBINC = ../zlib
-ZLIBLIB = ../zlib
-
-# Compiler, linker, lib and other tools
-CC = gcc
-LD = $(CC)
-AR_RC = ar rcs
-MKDIR_P = mkdir -p
-RANLIB = ranlib
-RM_F = rm -f
-LN_SF = ln -f -s
-
-LIBNAME=libpng15
-PNGMAJ = 15
-
-prefix=/usr/local
-INCPATH=$(prefix)/include
-LIBPATH=$(prefix)/lib
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-
-CDEBUG = -g -DPNG_DEBUG=5
-LDDEBUG =
-CRELEASE = -O2
-LDRELEASE = -s
-WARNMORE=-W -Wall
-CFLAGS = -I$(ZLIBINC) $(WARNMORE) $(CRELEASE)
-LDFLAGS = -L. -L$(ZLIBLIB) -lpng15 -lz -lm $(LDRELEASE)
-
-# File extensions
-O=.o
-A=.a
-E=
-
-# Variables
-OBJS =  png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O) \
-	pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O) \
-	pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
-
-# Targets
-all: $(LIBNAME)$(A) pngtest$(E)
-
-include scripts/pnglibconf.mak
-REMOVE = $(RM_F)
-DFNFLAGS = $(DEFS) $(CPPFLAGS)
-
-$(LIBNAME)$(A): $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-test: pngtest$(E)
-	./pngtest$(E)
-
-pngtest$(E): pngtest$(O) $(LIBNAME)$(A)
-	$(LD) -o $@ pngtest$(O) $(LDFLAGS)
-
-install: $(LIBNAME)$(A)
-	-@if [ ! -d $(DI)  ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME)  ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DI)/$(LIBNAME)/png.h
-	-@$(RM_F) $(DI)/$(LIBNAME)/pngconf.h
-	-@$(RM_F) $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h
-	-@$(RM_F) $(DI)/pngconf.h
-	-@$(RM_F) $(DI)/pnglibconf.h
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h \
-	$(DI)/$(LIBNAME)/pngconf.h \
-	$(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) -r $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-	-@$(RM_F) $(DL)/$(LIBNAME)$(A)
-	-@$(RM_F) $(DL)/libpng$(A)
-	cp $(LIBNAME)$(A) $(DL)/$(LIBNAME)$(A)
-	chmod 644 $(DL)/$(LIBNAME)$(A)
-	(cd $(DL); $(LN_SF) $(LIBNAME)$(A) libpng$(A))
-	(cd $(DI); $(LN_SF) libpng/* .;)
-
-clean:
-	$(RM_F) *.o $(LIBNAME)$(A) pngtest pngout.png pnglibconf.h
-
-png$(O):      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread$(O):  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest$(O):  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.amiga b/extern/libpng/include/scripts/makefile.amiga
deleted file mode 100644
index 228b5c22a7..0000000000
--- a/extern/libpng/include/scripts/makefile.amiga
+++ /dev/null
@@ -1,56 +0,0 @@
-# Commodore Amiga Makefile
-# makefile for libpng and SAS C V6.5x compiler
-# Copyright (C) 1995-2000 Wolf Faust
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-#
-# Location/path of zlib include files
-ZLIB=/zlib
-#compiler
-CC=sc
-#compiler flags
-# WARNING: a bug in V6.51 causes bad code with OPTGO
-#          So use V6.55 or set NOOPTGO!!!!!!!!!
-CFLAGS= NOSTKCHK PARMS=REG OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL\
-	OPTLOOP OPTRDEP=4 OPTDEP=4 OPTCOMP=4 INCLUDEDIR=$(ZLIB) \
-	DEFINE=PNG_INTERNAL
-#linker flags
-LDFLAGS= SD ND BATCH
-#link libs
-LDLIBS= libpng.lib libgz.lib LIB:scm.lib LIB:sc.lib Lib:amiga.lib
-# linker
-LN= slink
-# file deletion command
-RM= delete quiet
-# file copy command?
-CP= copy
-# library (.lib) file creation command
-AR= oml
-# make directory command
-MKDIR= makedir
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-all: libpng.lib pngtest
-
-libpng.lib: $(OBJS)
--$(RM) libpng.lib
-$(AR) libpng.lib r $(OBJS)
-
-$(OBJS): pngpriv.h png.h pngconf.h pnglibconf.h pnginfo.h pngstruct.h pngdebug.h
-
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-$(CP) scripts/pnglibconf.h.prebuilt pnglibconf.h
-
-pngtest: pngtest.o libpng.lib
-$(LN) <WITH <
-$(LDFLAGS)
-TO pngtest
-FROM LIB:c.o pngtest.o
-LIB $(LDLIBS)
-<
-
diff --git a/extern/libpng/include/scripts/makefile.atari b/extern/libpng/include/scripts/makefile.atari
deleted file mode 100644
index 1aeb7d5b7d..0000000000
--- a/extern/libpng/include/scripts/makefile.atari
+++ /dev/null
@@ -1,63 +0,0 @@
-# makefile for libpng
-# Copyright (C) 2002 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-#
-# Modified for LC56/ATARI assumes libz.lib is in same dir and uses default
-# rules for library management
-#
-CFLAGS=-I..\zlib -O
-LBR = png.lib
-LDFLAGS=-lpng -lz -lm
-
-# where make install puts libpng.a and png.h
-prefix=/usr/local
-INCPATH=$(prefix)/include
-LIBPATH=$(prefix)/lib
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-OBJS = $(LBR)(png.o) $(LBR)(pngset.o) $(LBR)(pngget.o) $(LBR)(pngrutil.o)\
-	$(LBR)(pngtrans.o) $(LBR)(pngwutil.o)\
-	$(LBR)(pngread.o) $(LBR)(pngerror.o) $(LBR)(pngwrite.o)\
-	$(LBR)(pngrtran.o) $(LBR)(pngwtran.o)\
-	$(LBR)(pngmem.o) $(LBR)(pngrio.o) $(LBR)(pngwio.o) $(LBR)(pngpread.o)
-
-all: $(LBR) pngtest.ttp
-
-$(LBR): $(OBJS)
-
-$(OBJS): pngpriv.h png.h pngconf.h pnglibconf.h pnginfo.h pngstruct.h pngdebug.h
-
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt pnglibconf.h
-
-pngtest.ttp: pngtest.o $(LBR)
-	$(CC) $(CFLAGS) $(LDFLAGS) -o$@ pngtest.o
-
-install: libpng.a
-	-@mkdir $(DESTDIR)$(INCPATH)
-	-@mkdir $(DESTDIR)$(INCPATH)/libpng
-	-@mkdir $(DESTDIR)$(LIBPATH)
-	-@rm -f $(DESTDIR)$(INCPATH)/png.h
-	-@rm -f $(DESTDIR)$(INCPATH)/pngconf.h
-	-@rm -f $(DESTDIR)$(INCPATH)/pnglibconf.h
-	cp png.h $(DESTDIR)$(INCPATH)/libpng
-	cp pngconf.h $(DESTDIR)$(INCPATH)/libpng
-	cp pnglibconf.h $(DESTDIR)$(INCPATH)/libpng
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/png.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pngconf.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pnglibconf.h
-	(cd $(DESTDIR)$(INCPATH); ln -f -s $(LIBNAME) libpng; \
-	ln -f -s $(LIBNAME)/* .)
diff --git a/extern/libpng/include/scripts/makefile.bc32 b/extern/libpng/include/scripts/makefile.bc32
deleted file mode 100644
index ebbd5ce3d2..0000000000
--- a/extern/libpng/include/scripts/makefile.bc32
+++ /dev/null
@@ -1,151 +0,0 @@
-# Makefile for libpng
-# 32-bit Borland C++ (Note: All modules are compiled in C mode)
-# To build the library, do:
-#       "make -fmakefile.bc32"
-#
-# -------------------- 32-bit Borland C++ --------------------
-
-### Absolutely necessary for this makefile to work
-.AUTODEPEND
-
-## Where zlib.h, zconf.h and zlib.lib are
-ZLIB_DIR=..\zlib
-
-## Compiler, linker and lib stuff
-CC=bcc32
-LD=bcc32
-LIB=tlib
-
-# -3 = 386, -4 = 486, -5 = Pentium etc.
-!ifndef TARGET_CPU
-#TARGET_CPU=-6
-!endif
-
-# Use this if you don't want Borland's fancy exception handling
-# (Caution: doesn't work with CBuilderX)
-#NOEHLIB=noeh32.lib
-
-!ifdef DEBUG
-CDEBUG=-v
-LDEBUG=-v
-!else
-CDEBUG=
-LDEBUG=
-!endif
-
-# STACKOFLOW=1
-!ifdef STACKOFLOW
-CDEBUG=$(CDEBUG) -N
-LDEBUG=$(LDEBUG) -N
-!endif
-
-# -O2 optimize for speed
-# -d  merge duplicate strings
-# -k- turn off standard stack frame
-# -w  display all warnings
-CFLAGS=-I$(ZLIB_DIR) -O2 -d -k- -w $(TARGET_CPU) $(CDEBUG)
-
-# -M  generate map file
-LDFLAGS=-L$(ZLIB_DIR) -M $(LDEBUG)
-
-## Variables
-OBJS = \
-	png.obj \
-	pngerror.obj \
-	pngget.obj \
-	pngmem.obj \
-	pngpread.obj \
-	pngread.obj \
-	pngrio.obj \
-	pngrtran.obj \
-	pngrutil.obj \
-	pngset.obj \
-	pngtrans.obj \
-	pngwio.obj \
-	pngwrite.obj \
-	pngwtran.obj \
-	pngwutil.obj
-
-LIBOBJS = \
-	+png.obj \
-	+pngerror.obj \
-	+pngget.obj \
-	+pngmem.obj \
-	+pngpread.obj \
-	+pngread.obj \
-	+pngrio.obj \
-	+pngrtran.obj \
-	+pngrutil.obj \
-	+pngset.obj \
-	+pngtrans.obj \
-	+pngwio.obj \
-	+pngwrite.obj \
-	+pngwtran.obj \
-	+pngwutil.obj
-
-LIBNAME=libpng.lib
-
-## Implicit rules
-# Braces let make "batch" calls to the compiler,
-# 2 calls instead of 12; space is important.
-.c.obj:
-	$(CC) $(CFLAGS) -c {$*.c }
-
-.c.exe:
-	$(CC) $(CFLAGS) $(LDFLAGS) $*.c $(LIBNAME) zlib.lib $(NOEHLIB)
-
-.obj.exe:
-	$(LD) $(LDFLAGS) $*.obj $(LIBNAME) zlib.lib $(NOEHLIB)
-
-## Major targets
-all: libpng pngtest
-
-libpng: $(LIBNAME)
-
-pngtest: pngtest.exe
-
-test: pngtest.exe
-	pngtest
-
-## Minor Targets
-
-# see scripts\pnglibconf.mak for how to make this file
-# with different options
-pnglibconf.h: scripts\pnglibconf.h.prebuilt
-	copy scripts\pnglibconf.h.prebuilt $@
-
-png.obj: png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.obj: pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.obj: pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.obj: pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.obj: pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.obj: pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.obj: pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.obj: pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.obj: pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.obj: pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.obj: pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.obj: pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.obj: pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.obj: pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.obj: pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtest.obj: pngtest.c png.h pngconf.h pnglibconf.h
-
-$(LIBNAME): $(OBJS)
-	-del $(LIBNAME)
-	$(LIB) $(LIBNAME) @&&|
-$(LIBOBJS), libpng
-|
-
-# Cleanup
-clean:
-	-del pnglibconf.h
-	-del *.obj
-	-del $(LIBNAME)
-	-del pngtest.exe
-	-del *.lst
-	-del *.map
-	-del *.tds
-	-del pngout.png
-
-# End of makefile for libpng
diff --git a/extern/libpng/include/scripts/makefile.beos b/extern/libpng/include/scripts/makefile.beos
deleted file mode 100644
index 749db78ad3..0000000000
--- a/extern/libpng/include/scripts/makefile.beos
+++ /dev/null
@@ -1,215 +0,0 @@
-# makefile for libpng on BeOS x86 ELF with gcc
-# modified from makefile.linux by Sander Stoks
-# Copyright (C) 2002, 2006, 2008, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1999 Greg Roelofs
-# Copyright (C) 1996, 1997 Andreas Dilger
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME=libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-CC=gcc
-AR_RC=ar rc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=ranlib
-RM_F=/bin/rm -f
-
-# Where the zlib library and include files are located
-ZLIBLIB=/usr/local/lib
-ZLIBINC=/usr/local/include
-
-ALIGN=
-# For i386:
-# ALIGN=-malign-loops=2 -malign-functions=2
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-
-# On BeOS, -O1 is actually better than -O3.  This is a known bug but it's
-# still here in R4.5
-CFLAGS=-I$(ZLIBINC) -W -Wall -O1 -funroll-loops \
-	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
-# LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng -lz
-LDFLAGS=-L. -Wl,-soname=$(LIBSOMAJ) -L$(ZLIBLIB) -lz
-
-# where make install puts libpng.a, libpng15.so*, and png.h
-prefix=/usr/local
-exec_prefix=$(prefix)
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS)
-
-.SUFFIXES:      .c .o
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-# try include scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo libs=\"-lpng15 -lz \"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-	cp $(LIBSO)* /boot/home/config/lib
-
-$(LIBSOMAJ): $(OBJSDLL)
-	$(CC) -nostart -Wl,-soname,$(LIBSOMAJ) -o \
-	$(LIBSOMAJ) $(OBJSDLL) $(LDFLAGS)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -L$(ZLIBLIB) -L. -lz -lpng15 -o pngtest pngtest.o
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) $(CFLAGS) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) -Wl,-rpath $(ZLIBLIB):$(DL) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	$(CC) $(CFLAGS) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngout.png libpng-config \
-	$(LIBSO) $(LIBSOMAJ)* pngtesti \
-	pnglibconf.h libpng.pc
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.bor b/extern/libpng/include/scripts/makefile.bor
deleted file mode 100644
index 96d5e861a3..0000000000
--- a/extern/libpng/include/scripts/makefile.bor
+++ /dev/null
@@ -1,161 +0,0 @@
-# Makefile for libpng
-# 16-bit Borland C++ (Note: All modules are compiled in C mode)
-# To build the library, do:
-#       "make -fmakefile.bor -DMODEL=c"
-# or:   "make -fmakefile.bor -DMODEL=l"
-#
-# ------------ Borland C++ ------------
-
-### Absolutely necessary for this makefile to work
-.AUTODEPEND
-
-## Where zlib.h, zconf.h and zlib_MODEL.lib are
-ZLIB_DIR=..\zlib
-
-## Compiler, linker and lib stuff
-CC=bcc
-LD=bcc
-LIB=tlib
-
-!ifndef MODEL
-MODEL=l
-!endif
-
-MODEL_ARG=-m$(MODEL)
-
-#TARGET_CPU=3
-# 2 = 286, 3 = 386, etc.
-!ifndef TARGET_CPU
-TARGET_CPU=2
-!endif
-
-# Use this if you don't want Borland's fancy exception handling
-# (for Borland C++ 4.0 or later)
-#NOEHLIB=noeh$(MODEL).lib
-
-!ifdef DEBUG
-CDEBUG=-v
-LDEBUG=-v
-!else
-CDEBUG=
-LDEBUG=
-!endif
-
-# STACKOFLOW=1
-!ifdef STACKOFLOW
-CDEBUG=$(CDEBUG) -N
-LDEBUG=$(LDEBUG) -N
-!endif
-
-# -X- turn on dependency generation in the object file
-# -w  set all warnings on
-# -O2 optimize for speed
-# -Z  global optimization
-CFLAGS=-O2 -Z -X- -w -I$(ZLIB_DIR) -$(TARGET_CPU) $(MODEL_ARG) $(CDEBUG)
-
-# -M  generate map file
-LDFLAGS=-M -L$(ZLIB_DIR) $(MODEL_ARG) $(LDEBUG)
-
-## Variables
-
-OBJS = \
-	png.obj \
-	pngerror.obj \
-	pngget.obj \
-	pngmem.obj \
-	pngpread.obj \
-	pngread.obj \
-	pngrio.obj \
-	pngrtran.obj \
-	pngrutil.obj \
-	pngset.obj \
-	pngtrans.obj \
-	pngwio.obj \
-	pngwrite.obj \
-	pngwtran.obj \
-	pngwutil.obj
-
-LIBOBJS = \
-	+png.obj \
-	+pngerror.obj \
-	+pngget.obj \
-	+pngmem.obj \
-	+pngpread.obj \
-	+pngread.obj \
-	+pngrio.obj \
-	+pngrtran.obj \
-	+pngrutil.obj \
-	+pngset.obj \
-	+pngtrans.obj \
-	+pngwio.obj \
-	+pngwrite.obj \
-	+pngwtran.obj \
-	+pngwutil.obj
-
-LIBNAME=libpng$(MODEL).lib
-
-## Implicit rules
-
-# Braces let make "batch" calls to the compiler,
-# 2 calls instead of 12; space is important.
-.c.obj:
-	$(CC) $(CFLAGS) -c {$*.c }
-
-.c.exe:
-	$(CC) $(CFLAGS) $(LDFLAGS) $*.c $(LIBNAME) zlib_$(MODEL).lib $(NOEHLIB)
-
-## Major targets
-
-all: libpng pngtest
-
-# try !inlude scripts\pnglibconf.mak for more options
-pnglibconf.h: scripts\pnglibconf.h.prebuilt
-	copy scripts\pnglibconf.h.prebuilt $@
-
-libpng: $(LIBNAME)
-
-pngtest: pngtest$(MODEL).exe
-
-test: pngtest$(MODEL).exe
-	pngtest$(MODEL)
-
-## Minor Targets
-
-png.obj: png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.obj: pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.obj: pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.obj: pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.obj: pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.obj: pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.obj: pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.obj: pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.obj: pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.obj: pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.obj: pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.obj: pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.obj: pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.obj: pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.obj: pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-$(LIBNAME): $(OBJS)
-	-del $(LIBNAME)
-	$(LIB) $(LIBNAME) @&&|
-$(LIBOBJS), libpng$(MODEL)
-|
-
-pngtest$(MODEL).obj: pngtest.c png.h pngconf.h pnglibconf.h
-	$(CC) $(CFLAGS) -opngtest$(MODEL) -c pngtest.c
-
-pngtest$(MODEL).exe: pngtest$(MODEL).obj
-	$(LD) $(LDFLAGS) pngtest$(MODEL).obj $(LIBNAME) zlib_$(MODEL).lib $(NOEHLIB)
-
-# Clean up anything else you want
-clean:
-	-del pnglibconf.h
-	-del *.obj
-	-del *.exe
-	-del *.lib
-	-del *.lst
-	-del *.map
-
-# End of makefile for libpng
diff --git a/extern/libpng/include/scripts/makefile.cegcc b/extern/libpng/include/scripts/makefile.cegcc
deleted file mode 100644
index fbc3d78bc4..0000000000
--- a/extern/libpng/include/scripts/makefile.cegcc
+++ /dev/null
@@ -1,116 +0,0 @@
-# Makefile for creating Windows CE release archives, with the
-# mingw32ce compiler.
-
-# Last updated: 22-Jul-2008
-
-# Copyright (C) 2008 Vincent Torri
-
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# To get some help, type
-#
-# make help
-#
-# To create the archives
-#
-# make
-#
-# To remove everything, type:
-#
-# make clean
-
-VERMAJ = 1
-VERMIN = 5
-VERMIC = 10
-VER = $(VERMAJ).$(VERMIN).$(VERMIC)
-NAME = libpng
-PACKAGE = $(NAME)-$(VER)
-
-BIN = libpng15-0.dll
-LIB = libpng15.a libpng15.dll.a libpng.a libpng.dll.a
-INCLUDE = png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-PC = libpng15.pc libpng.pc
-
-MANIFESTVERBIN = "Libpng-$(VER): Binary files"
-MANIFESTVERDEV = "Libpng-$(VER): Developer files"
-MANIFESTVERDESC = "Libpng: the official PNG reference library"
-
-all: $(NAME)
-
-$(NAME): remove-old copy-src compilation copy manifest archive
-	@echo " * Removal of the directories"
-	@rm -rf $(PACKAGE)/ $(PACKAGE)-bin/ $(PACKAGE)-dev/
-
-remove-old:
-	@echo " * Removal of the old files"
-	@rm -rf $(PACKAGE)-bin*
-	@rm -rf $(PACKAGE)-dev*
-
-copy-src:
-	@echo " * Copy of source files"
-	@cp -R ../src/$(PACKAGE) .
-	@echo " * Creation of directories and files"
-	@mkdir -p $(PACKAGE)-bin/bin
-	@mkdir -p $(PACKAGE)-bin/manifest
-	@mkdir -p $(PACKAGE)-dev/lib/pkgconfig
-	@mkdir -p $(PACKAGE)-dev/include/$(NAME)$(VERMAJ)$(VERMIN)
-	@mkdir -p $(PACKAGE)-dev/manifest
-	@touch $(PACKAGE)-bin/manifest/$(PACKAGE)-bin.mft
-	@touch $(PACKAGE)-bin/manifest/$(PACKAGE)-bin.ver
-	@touch $(PACKAGE)-dev/manifest/$(PACKAGE)-dev.mft
-	@touch $(PACKAGE)-dev/manifest/$(PACKAGE)-dev.ver
-
-compilation:
-	@echo " * Compilation of $(PACKAGE)"
-	cd $(PACKAGE) && CPPFLAGS="$(CPPFLAGS) -DPNG_CONSOLE_IO_SUPPORTED -D_WIN32_WCE=0x0420" \
-		CFLAGS="$(CFLAGS) -mms-bitfields -O3 -pipe -fomit-frame-pointer" \
-		LDFLAGS="$(LDFLAGS) -Wl,--enable-auto-import -Wl,-s" \
-		./configure --prefix=/opt/wince --host=arm-mingw32ce && make
-
-copy:
-	@echo " * Copy of binary and development files"
-	@for i in $(BIN); do \
-	  cp $(PACKAGE)/.libs/$$i $(PACKAGE)-bin/bin; \
-	done
-	@for i in $(LIB); do \
-	  cp $(PACKAGE)/.libs/$$i $(PACKAGE)-dev/lib; \
-	done
-	@for i in $(INCLUDE); do \
-	  cp $(PACKAGE)/$$i $(PACKAGE)-dev/include/$(NAME)$(VERMAJ)$(VERMIN); \
-	done
-	@for i in $(PC); do \
-	  cp $(PACKAGE)/$$i $(PACKAGE)-dev/lib/pkgconfig; \
-	done
-
-manifest:
-	@echo " * Creation of the manifest"
-	@cd $(PACKAGE)-bin && find * >> manifest/$(PACKAGE)-bin.mft
-	@cd $(PACKAGE)-bin && \
-	  echo $(MANIFESTVERBIN) >> manifest/$(PACKAGE)-bin.ver && \
-	  echo $(MANIFESTVERDESC) >> manifest/$(PACKAGE)-bin.ver
-	@cd $(PACKAGE)-dev && find * >> manifest/$(PACKAGE)-dev.mft
-	@cd $(PACKAGE)-dev && \
-	  echo $(MANIFESTVERDEV) >> manifest/$(PACKAGE)-dev.ver && \
-	  echo $(MANIFESTVERDESC) >> manifest/$(PACKAGE)-dev.ver
-
-archive:
-	@echo " * Creation of the archives"
-	@tar cf $(PACKAGE)-bin.tar $(PACKAGE)-bin
-	@bzip2 -9 $(PACKAGE)-bin.tar
-	@tar cf $(PACKAGE)-dev.tar $(PACKAGE)-dev
-	@bzip2 -9 $(PACKAGE)-dev.tar
-
-clean:
-	@echo " * Cleaning"
-	@rm -rf $(PACKAGE)*
-
-help:
-	@echo
-	@echo "To create the archives, type:"
-	@echo " make"
-	@echo
-	@echo "To remove everything, type:"
-	@echo " make clean"
-	@echo
diff --git a/extern/libpng/include/scripts/makefile.darwin b/extern/libpng/include/scripts/makefile.darwin
deleted file mode 100644
index 337a8151eb..0000000000
--- a/extern/libpng/include/scripts/makefile.darwin
+++ /dev/null
@@ -1,220 +0,0 @@
-# makefile for libpng on Darwin / Mac OS X
-# Copyright (C) 2002, 2004, 2006, 2008, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 2001 Christoph Pfisterer
-# derived from makefile.linux:
-#  Copyright (C) 1998, 1999 Greg Roelofs
-#  Copyright (C) 1996, 1997 Andreas Dilger
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# where "make install" puts libpng.a, libpng15.dylib, png.h, pngconf.h,
-# and pnglibconf.h
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-ZLIBLIB=../zlib
-ZLIBINC=../zlib
-
-# Library name:
-LIBNAME = libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).dylib
-LIBSOMAJ=$(LIBNAME).$(PNGMAJ).dylib
-LIBSOREL=$(LIBNAME).$(PNGMAJ).$(RELEASE).dylib
-OLDSO=libpng.dylib
-
-# Utilities:
-CC=cc
-AR_RC=ar rc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=ranlib
-RM_F=/bin/rm -f
-ARCH="-arch i386 -arch x86_64"
-
-# CFLAGS=-I$(ZLIBINC) -W -Wall -O3 -funroll-loops
-CFLAGS=-I$(ZLIBINC) -W -Wall -O -funroll-loops $(ARCH)
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng15 -lz $(ARCH)
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -fno-common -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	$(CC) -dynamiclib \
-	 -install_name $(LIBPATH)/$(LIBSOMAJ) \
-	 -current_version 15 -compatibility_version 15 \
-	 -o $(LIBSOMAJ) \
-	 $(OBJSDLL) -L$(ZLIBLIB) -lz
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	$(RANLIB) $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	$(CC) $(CFLAGS) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngout.png libpng-config \
-	libpng.pc $(LIBNAME).*dylib pngtesti pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.dec b/extern/libpng/include/scripts/makefile.dec
deleted file mode 100644
index 5301d87d33..0000000000
--- a/extern/libpng/include/scripts/makefile.dec
+++ /dev/null
@@ -1,202 +0,0 @@
-# makefile for libpng on DEC Alpha Unix
-# Copyright (C) 2000-2002, 2006, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-PNGMAJ = 15
-LIBNAME = libpng15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-AR_RC=ar rc
-CC=cc
-MKDIR_P=mkdir
-LN_SF=ln -f -s
-RANLIB=ranlib
-RM_F=/bin/rm -f
-
-# where make install puts libpng.a and png.h
-prefix=/usr/local
-exec_prefix=$(prefix)
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-# Where the zlib library and include files are located
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-ZLIBLIB=../zlib
-ZLIBINC=../zlib
-
-CFLAGS=-std -w1 -I$(ZLIBINC) -O # -g -DPNG_DEBUG=1
-LDFLAGS=-L$(ZLIBLIB) -rpath $(ZLIBLIB) libpng.a -lz -lm
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-all: $(LIBSO) libpng.a pngtest libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@  $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo ccopts=\"-std\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJS)
-	$(CC) -shared -o $@ $(OBJS) -L$(ZLIBLIB) \
-	-soname $(LIBSOMAJ)
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@/bin/rm -f $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@/bin/rm -f $(DI)/libpng
-	(cd $(DI); $(LN_SF)(LIBNAME) libpng; $(LN_SF)(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@/bin/rm -f $(DL)/libpng.a
-	(cd $(DL); $(LN_SF)(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@/bin/rm -f $(DM)/man3/libpng.3
-	-@/bin/rm -f $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@/bin/rm -f $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@/bin/rm -f $(DB)/libpng-config
-	-@/bin/rm -f $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF)(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -w1 -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB)  -R$(ZLIBLIB) -R$(DL) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) -w1 -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) -R$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	/bin/rm -f *.o libpng.a pngtest pngtesti pngout.png \
-	libpng-config $(LIBSO) $(LIBSOMAJ)* \
-	libpng.pc pnglibconf.h
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.dj2 b/extern/libpng/include/scripts/makefile.dj2
deleted file mode 100644
index 87a05a364a..0000000000
--- a/extern/libpng/include/scripts/makefile.dj2
+++ /dev/null
@@ -1,62 +0,0 @@
-# DJGPP (DOS gcc) makefile for libpng
-# Copyright (C) 2002, 2006, 2009-2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# where make install will put libpng.a and png.h
-#prefix=/usr/local
-prefix=.
-INCPATH=$(prefix)/include
-LIBPATH=$(prefix)/lib
-
-CC=gcc
-CFLAGS=-I../zlib -O -DPNG_NO_SNPRINTF
-LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
-
-RANLIB=ranlib
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o pngwtran.o \
-	pngmem.o pngerror.o pngpread.o
-
-all: libpng.a pngtest
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	ar rc $@  $(OBJS)
-	$(RANLIB) $@
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-	coff2exe pngtest
-
-test: pngtest
-	./pngtest
-clean:
-	rm -f *.o libpng.a pngtest pngout.png pnglibconf.h
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.elf b/extern/libpng/include/scripts/makefile.elf
deleted file mode 100644
index 5af43b1845..0000000000
--- a/extern/libpng/include/scripts/makefile.elf
+++ /dev/null
@@ -1,263 +0,0 @@
-# makefile for libpng.a and libpng15.so on Linux ELF with gcc
-# Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2011 Greg Roelofs
-# and Glenn Randers-Pehrson
-# Copyright (C) 1996, 1997 Andreas Dilger
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Modified for Debian by Junichi Uekawa and Josselin Mouette
-# Major modifications are:
-#    * link libpng explicitly with libz and libm
-#    * $(OLDSO).15 is a symlink rather than a different library
-#    * versioned symbols
-
-# Library name:
-LIBNAME = libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-OLDSOMAJ=libpng.so.15
-
-# Utilities:
-AR_RC=ar rc
-CC=gcc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=ranlib
-RM_F=/bin/rm -f
-
-# where "make install" puts libpng15.a, libpng15.so*,
-# libpng15/png.h, libpng15/pngconf.h, and libpng15/pnglibconf.h
-# Prefix must be a full pathname.
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located.
-ZLIBLIB=/usr/local/lib
-ZLIBINC=/usr/local/include
-# ZLIBLIB=../zlib
-# ZLIBINC=../zlib
-
-ALIGN=
-# for i386:
-#ALIGN=-malign-loops=2 -malign-functions=2
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-
-# for pgcc version 2.95.1, -O3 is buggy; don't use it.
-
-CFLAGS=-W -Wall -D_REENTRANT -O2 \
-	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
-
-LDFLAGS=-L. -lpng15
-LDFLAGS_A=libpng.a -lz -lm
-LIBADDFLAGS=-lz -lm
-
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -fPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest pngtest-static libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng.syms: png.h pngconf.h pnglibconf.h
-	$(CC) $(CFLAGS) -E -DPNG_BUILDSYMS -DPNG_INTERNAL png.h |\
-	awk -F '[\t [\\]();]' -v PNGMAJ=$(PNGMAJ) 'BEGIN{printf("PNG15_%s {global:\n",PNGMAJ)}\
-	{ for (i=1;i+2<=NF;++i)\
-		if ($$(i)=="PNG_FUNCTION_EXPORT" && $$(i+2)=="END")\
-			print $$(i+1) ";";\
-	for (i=1;i+1<=NF;++i)\
-		if ($$(i)=="PNG_DATA_EXPORT")\
-			print $$(i+1) ";";}\
-	END{print "local: *; };"}' >$@.new
-	$(RM_F) $@
-	mv $@.new $@
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo L_opts=\"\"; \
-	echo R_opts=\"\"; \
-	echo libs=\"-lpng15\"; \
-	echo all_libs=\"-lpng15 $(LIBADDFLAGS)\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL) libpng.syms
-	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) \
-	-Wl,-version-script,libpng.syms \
-	-o $(LIBSOMAJ) \
-	$(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-pngtest-static: pngtest.o libpng.a
-	$(CC) -o pngtest-static $(CFLAGS) pngtest.o $(LDFLAGS_A)
-
-test: pngtest pngtest-static
-	@echo ""
-	@echo "   Running pngtest dynamically linked with $(LIBSO):"
-	@echo ""
-	LD_LIBRARY_PATH=".:${LD_LIBRARY_PATH}" ./pngtest
-	@echo ""
-	@echo "   Running pngtest statically linked with libpng.a:"
-	@echo ""
-	./pngtest-static
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) -Wl, -rpath,$(DL) -Wl,-rpath,$(ZLIBLIB) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	$(CC) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a libpng.syms pngtest pngout.png libpng-config \
-	$(LIBSO) $(LIBSOMAJ)* pngtest-static pngtesti \
-	libpng.pc pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.freebsd b/extern/libpng/include/scripts/makefile.freebsd
deleted file mode 100644
index 994608c993..0000000000
--- a/extern/libpng/include/scripts/makefile.freebsd
+++ /dev/null
@@ -1,53 +0,0 @@
-# makefile for libpng under FreeBSD
-# Copyright (C) 2002, 2007, 2009 Glenn Randers-Pehrson and Andrey A. Chernov
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-PREFIX?=        /usr/local
-SHLIB_VER?=     15
-
-LIB=		png
-SHLIB_MAJOR=	${SHLIB_VER}
-SHLIB_MINOR=	0
-NOPROFILE=	YES
-NOOBJ=          YES
-
-# where make install puts libpng.a and png.h
-DESTDIR=	${PREFIX}
-LIBDIR=		/lib
-INCS=		png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-INCSDIR=	/include/libpng
-INCDIR=		${INCSDIR}		# for 4.x bsd.lib.mk
-MAN=		libpng.3 libpngpf.3 png.5
-MANDIR=		/man/man
-SYMLINKS=       libpng/png.h ${INCSDIR}/../png.h \
-		libpng/pngconf.h ${INCSDIR}/../pngconf.h \
-		libpng/pnglibconf.h ${INCSDIR}/../pnglibconf.h
-LDADD+=         -lm -lz
-DPADD+=         ${LIBM} ${LIBZ}
-
-CFLAGS+= -I.
-
-SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
-	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
-	pngwtran.c pngmem.c pngerror.c pngpread.c
-
-pngtest: pngtest.o libpng.a
-	${CC} ${CFLAGS} -L. -static -o pngtest pngtest.o -lpng -lz -lm
-
-CLEANFILES= pngtest pngtest.o pngout.png
-
-test: pngtest
-	./pngtest
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-.include <bsd.lib.mk>
diff --git a/extern/libpng/include/scripts/makefile.gcc b/extern/libpng/include/scripts/makefile.gcc
deleted file mode 100644
index 2e5b611367..0000000000
--- a/extern/libpng/include/scripts/makefile.gcc
+++ /dev/null
@@ -1,87 +0,0 @@
-# makefile for libpng using gcc (generic, static library)
-# Copyright (C) 2008 Glenn Randers-Pehrson
-# Copyright (C) 2000 Cosmin Truta
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Location of the zlib library and include files
-ZLIBINC = ../zlib
-ZLIBLIB = ../zlib
-
-# Compiler, linker, lib and other tools
-CC = gcc
-LD = $(CC)
-AR_RC = ar rcs
-RANLIB = ranlib
-RM_F = rm -f
-
-CDEBUG = -g -DPNG_DEBUG=5
-LDDEBUG =
-CRELEASE = -O2
-LDRELEASE = -s
-#CFLAGS = -W -Wall $(CDEBUG)
-CFLAGS = -W -Wall $(CRELEASE)
-#LDFLAGS = $(LDDEBUG)
-LDFLAGS = $(LDRELEASE)
-LIBS = -lz -lm
-
-# File extensions
-O=.o
-A=.a
-EXE=
-
-# Variables
-OBJS =  png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O) \
-	pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O) \
-	pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
-
-# Targets
-all: static
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-.c$(O):
-	$(CC) -c $(CFLAGS) -I$(ZLIBINC) $<
-
-static: libpng$(A) pngtest$(EXE)
-
-shared:
-	@echo This is a generic makefile that cannot create shared libraries.
-	@echo Please use a configuration that is specific to your platform.
-	@false
-
-libpng$(A): $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-test: pngtest$(EXE)
-	./pngtest$(EXE)
-
-pngtest$(EXE): pngtest$(O) libpng$(A)
-	$(LD) $(LDFLAGS) -L$(ZLIBLIB) -o $@ pngtest$(O) libpng$(A) $(LIBS)
-
-clean:
-	$(RM_F) *$(O) libpng$(A) pngtest$(EXE) pngout.png pnglibconf.h
-
-png$(O):      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread$(O):  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest$(O):  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.hp64 b/extern/libpng/include/scripts/makefile.hp64
deleted file mode 100644
index b5b631d11c..0000000000
--- a/extern/libpng/include/scripts/makefile.hp64
+++ /dev/null
@@ -1,224 +0,0 @@
-# makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
-# Copyright (C) 1999-2002, 2006, 2009, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42
-# contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Where the zlib library and include files are located
-ZLIBLIB=/opt/zlib/lib
-ZLIBINC=/opt/zlib/include
-
-# Note that if you plan to build a libpng shared library, zlib must also
-# be a shared library, which zlib's configure does not do.  After running
-# zlib's configure, edit the appropriate lines of makefile to read:
-#   CFLAGS=-O1 -DHAVE_UNISTD -DUSE_MAP -fPIC \
-#   LDSHARED=ld -b
-#   SHAREDLIB=libz.sl
-
-# Library name:
-LIBNAME = libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).sl
-LIBSOMAJ=$(LIBNAME).sl.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.sl
-
-# Utilities:
-AR_RC=ar rc
-CC=cc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=ranlib
-RM_F=/bin/rm -f
-
-CFLAGS=-I$(ZLIBINC) -O -Ae -Wl,+vnocompatwarnings +DD64 \
--D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 +Z -DHAVE_UNISTD_H -DUSE_MMAP
-# Caution: be sure you have built zlib with the same CFLAGS.
-CCFLAGS=-I$(ZLIBINC) -O -Ae -Wl,+vnocompatwarnings +DD64 \
--D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 +Z -DHAVE_UNISTD_H -DUSE_MMAP
-
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
-
-# where make install puts libpng.a, libpng15.sl, and png.h
-prefix=/opt/libpng
-exec_prefix=$(prefix)
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:	.c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) +z -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo ccopts=\"-Ae +DA1.1 +DS2.0\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	$(LD) -b +s \
-	+h $(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) $(CCFLAGS) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) $(CCFLAGS) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
-	libpng-config $(LIBSO) $(LIBSOMAJ)* \
-	libpng.pc pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.hpgcc b/extern/libpng/include/scripts/makefile.hpgcc
deleted file mode 100644
index 3fe21177a4..0000000000
--- a/extern/libpng/include/scripts/makefile.hpgcc
+++ /dev/null
@@ -1,230 +0,0 @@
-# makefile for libpng on HP-UX using GCC with the HP ANSI/C linker.
-# Copyright (C) 2002, 2006-2008, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 2001, Laurent faillie
-# Copyright (C) 1998, 1999 Greg Roelofs
-# Copyright (C) 1996, 1997 Andreas Dilger
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME = libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).sl
-LIBSOMAJ=$(LIBNAME).sl.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.sl
-
-# Utilities:
-CC=gcc
-LD=ld
-AR_RC=ar rc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=ranlib
-RM_F=/bin/rm -f
-
-# where "make install" puts libpng.a, $(OLDSO)*, png.h, pngconf.h
-# and pnglibconf.h
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-ZLIBLIB=/opt/zlib/lib
-ZLIBINC=/opt/zlib/include
-
-# Note that if you plan to build a libpng shared library, zlib must also
-# be a shared library, which zlib's configure does not do.  After running
-# zlib's configure, edit the appropriate lines of makefile to read:
-#   CFLAGS=-O1 -DHAVE_UNISTD -DUSE_MAP -fPIC \
-#   LDSHARED=ld -b
-#   SHAREDLIB=libz.sl
-
-ALIGN=
-# for i386:
-#ALIGN=-malign-loops=2 -malign-functions=2
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-
-# for pgcc version 2.95.1, -O3 is buggy; don't use it.
-
-CFLAGS=-I$(ZLIBINC) -W -Wall -O3 -funroll-loops -DPNG_NO_MMX_CODE \
-	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
-#LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng15 -lz -lm
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng15 -lz -lm
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -fPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	$(LD) -b +s \
-	+h $(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) -Wl,-rpath,$(DL) -Wl,-rpath,$(ZLIBLIB) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
-	libpng-config $(LIBSO) $(LIBSOMAJ)* \
-	libpng.pc pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.hpux b/extern/libpng/include/scripts/makefile.hpux
deleted file mode 100644
index 650ab4f662..0000000000
--- a/extern/libpng/include/scripts/makefile.hpux
+++ /dev/null
@@ -1,221 +0,0 @@
-# makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
-# Copyright (C) 1999-2002, 2006, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42
-# contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Where the zlib library and include files are located
-ZLIBLIB=/opt/zlib/lib
-ZLIBINC=/opt/zlib/include
-
-# Note that if you plan to build a libpng shared library, zlib must also
-# be a shared library, which zlib's configure does not do.  After running
-# zlib's configure, edit the appropriate lines of makefile to read:
-#   CFLAGS=-O1 -DHAVE_UNISTD -DUSE_MAP -fPIC \
-#   LDSHARED=ld -b
-#   SHAREDLIB=libz.sl
-
-# Library name:
-LIBNAME = libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).sl
-LIBSOMAJ=$(LIBNAME).sl.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.sl
-
-# Utilities:
-AR_RC=ar rc
-CC=cc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=ranlib
-RM_F=/bin/rm -f
-
-# where make install puts libpng.a, libpng15.sl, and png.h
-prefix=/opt/libpng
-exec_prefix=$(prefix)
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-CFLAGS=-I$(ZLIBINC) -O -Ae +DA1.1 +DS2.0
-# Caution: be sure you have built zlib with the same CFLAGS.
-CCFLAGS=-I$(ZLIBINC) -O -Ae +DA1.1 +DS2.0
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:	.c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) +z -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo ccopts=\"-Ae +DA1.1 +DS2.0\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	$(LD) -b +s \
-	+h $(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) $(CCFLAGS) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) $(CCFLAGS) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
-	libpng-config $(LIBSO) $(LIBSOMAJ)* \
-	libpng.pc pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.ibmc b/extern/libpng/include/scripts/makefile.ibmc
deleted file mode 100644
index 209d513b1c..0000000000
--- a/extern/libpng/include/scripts/makefile.ibmc
+++ /dev/null
@@ -1,82 +0,0 @@
-# Makefile for libpng (static)
-# IBM C version 3.x for Win32 and OS/2
-# Copyright (C) 2006 Glenn Randers-Pehrson
-# Copyright (C) 2000 Cosmin Truta
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-#
-# Notes:
-#   Derived from makefile.std
-#   All modules are compiled in C mode
-#   Tested under Win32, expected to work under OS/2
-#   Can be easily adapted for IBM VisualAge/C++ for AIX
-
-# Location of the zlib library and include files
-ZLIBINC = ../zlib
-ZLIBLIB = ../zlib
-
-# Compiler, linker, lib and other tools
-CC = icc
-LD = ilink
-AR = ilib
-RM = del
-
-CFLAGS = -I$(ZLIBINC) -Mc -O2 -W3
-LDFLAGS =
-
-# File extensions
-O=.obj
-A=.lib
-E=.exe
-
-# Variables
-OBJS = png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O) \
-	pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O) \
-	pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
-
-LIBS = libpng$(A) $(ZLIBLIB)/zlib$(A)
-
-# Targets
-all: libpng$(A) pngtest$(E)
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng$(A): $(OBJS)
-	$(AR) -out:$@ $(OBJS)
-
-test: pngtest$(E)
-	pngtest$(E)
-
-pngtest: pngtest$(E)
-
-pngtest$(E): pngtest$(O) libpng$(A)
-	$(LD) $(LDFLAGS) pngtest$(O) $(LIBS)
-
-clean:
-	$(RM) *$(O)
-	$(RM) libpng$(A)
-	$(RM) pnglibconf.h
-	$(RM) pngtest$(E)
-	$(RM) pngout.png
-
-png$(O):      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread$(O):  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest$(O):  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.intel b/extern/libpng/include/scripts/makefile.intel
deleted file mode 100644
index 1cb9ef3749..0000000000
--- a/extern/libpng/include/scripts/makefile.intel
+++ /dev/null
@@ -1,110 +0,0 @@
-# Makefile for libpng
-# Microsoft Visual C++ with Intel C/C++ Compiler 4.0 and later
-
-# Copyright (C) 2006 Glenn Randers-Pehrson
-# Copyright (C) 2000, Pawel Mrochen, based on makefile.msc which is
-# copyright 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-#
-# To use, do "nmake /f scripts\makefile.intel"
-#
-# ------------------- Intel C/C++ Compiler 4.0 and later -------------------
-
-# Where the zlib library and include files are located
-ZLIBLIB=..\zlib
-ZLIBINC=..\zlib
-
-# Target CPU
-CPU=6		# Pentium II
-#CPU=5		# Pentium
-
-# Calling convention
-CALLING=r	# __fastcall
-#CALLING=z	# __stdcall
-#CALLING=d	# __cdecl
-
-# Uncomment next to put error messages in a file
-#ERRFILE=>>pngerrs
-
-# --------------------------------------------------------------------------
-
-CC=icl -c
-CFLAGS=-O2 -G$(CPU)$(CALLING) -Qip -Qunroll4 -I$(ZLIBINC) -nologo
-LD=link
-LDFLAGS=/SUBSYSTEM:CONSOLE /NOLOGO
-
-O=.obj
-
-OBJS=png$(O) pngset$(O) pngget$(O) pngrutil$(O) pngtrans$(O) pngwutil$(O) \
-pngmem$(O) pngpread$(O) pngread$(O) pngerror$(O) pngwrite$(O) \
-pngrtran$(O) pngwtran$(O) pngrio$(O) pngwio$(O)
-
-all: test
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngget$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngmem$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngrio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngwio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-libpng.lib: $(OBJS)
-	if exist libpng.lib del libpng.lib
-	lib /NOLOGO /OUT:libpng.lib $(OBJS)
-
-pngtest.exe: pngtest.obj libpng.lib
-	$(LD) $(LDFLAGS) /OUT:pngtest.exe pngtest.obj libpng.lib $(ZLIBLIB)\zlib.lib
-
-pngtest$(O): png.h pngconf.h pnglibconf.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-test: pngtest.exe
-	pngtest.exe
-
-
-# End of makefile for libpng
diff --git a/extern/libpng/include/scripts/makefile.knr b/extern/libpng/include/scripts/makefile.knr
deleted file mode 100644
index 18a39f5375..0000000000
--- a/extern/libpng/include/scripts/makefile.knr
+++ /dev/null
@@ -1,109 +0,0 @@
-# makefile for libpng
-# Copyright (C) 2002, 2006, 2009 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-#
-# This makefile requires the file ansi2knr.c, which you can get
-# from the Ghostscript ftp site at ftp://ftp.cs.wisc.edu/ghost/
-# If you have libjpeg, you probably already have ansi2knr.c in the jpeg
-# source distribution.
-
-# where make install puts libpng.a and png.h
-prefix=/usr/local
-INCPATH=$(prefix)/include
-LIBPATH=$(prefix)/lib
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-CC=cc
-CFLAGS=-I../zlib -O
-LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
-# flags for ansi2knr
-ANSI2KNRFLAGS=
-
-RANLIB=ranlib
-#RANLIB=echo
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-all: ansi2knr libpng.a pngtest
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-# general rule to allow ansi2knr to work
-.c.o:
-	./ansi2knr $*.c T$*.c
-	$(CC) $(CFLAGS) -c T$*.c
-	rm -f T$*.c $*.o
-	mv T$*.o $*.o
-
-ansi2knr: ansi2knr.c
-	$(CC) $(CFLAGS) $(ANSI2KNRFLAGS) -o ansi2knr ansi2knr.c
-
-libpng.a: ansi2knr $(OBJS)
-	ar rc $@  $(OBJS)
-	$(RANLIB) $@
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install: libpng.a png.h pngconf.h pnglibconf.h
-	-@mkdir $(DESTDIR)$(INCPATH)
-	-@mkdir $(DESTDIR)$(INCPATH)/libpng
-	-@mkdir $(DESTDIR)$(LIBPATH)
-	-@rm -f $(DESTDIR)$(INCPATH)/png.h
-	-@rm -f $(DESTDIR)$(INCPATH)/pngconf.h
-	cp png.h $(DESTDIR)$(INCPATH)/libpng
-	cp pngconf.h $(DESTDIR)$(INCPATH)/libpng
-	cp pnglibconf.h $(DESTDIR)$(INCPATH)/libpng
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/png.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pngconf.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pnglibconf.h
-	(cd $(DESTDIR)$(INCPATH); ln -f -s libpng/* .)
-	cp libpng.a $(DESTDIR)$(LIBPATH)
-	chmod 644 $(DESTDIR)$(LIBPATH)/libpng.a
-
-clean:
-	rm -f *.o libpng.a pngtest pngout.png ansi2knr pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.linux b/extern/libpng/include/scripts/makefile.linux
deleted file mode 100644
index f1c75b654e..0000000000
--- a/extern/libpng/include/scripts/makefile.linux
+++ /dev/null
@@ -1,239 +0,0 @@
-# makefile for libpng.a and libpng15.so on Linux ELF with gcc
-# Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2011 Greg Roelofs and
-# Glenn Randers-Pehrson
-# Copyright (C) 1996, 1997 Andreas Dilger
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME = libpng15
-PNGMAJ = 15
-RELEASE = 10
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-AR_RC=ar rc
-CC=gcc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=ranlib
-RM_F=/bin/rm -f
-
-# where "make install" puts libpng15.a, libpng15.so*,
-# libpng15/png.h, libpng15/pngconf.h, and libpng15/pnglibconf.h
-# Prefix must be a full pathname.
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located.
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-ZLIBLIB=../zlib
-ZLIBINC=../zlib
-
-ALIGN=
-# for i386:
-#ALIGN=-malign-loops=2 -malign-functions=2
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-
-# for pgcc version 2.95.1, -O3 is buggy; don't use it.
-
-CFLAGS=-I$(ZLIBINC) -W -Wall -O3 -funroll-loops \
-	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
-
-LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng15 -lz -lm
-LDFLAGS_A=-L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) libpng.a -lz -lm
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS =  png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -fPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest pngtest-static libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo R_opts=\"-Wl,-rpath,$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-pngtest-static: pngtest.o libpng.a
-	$(CC) -o pngtest-static $(CFLAGS) pngtest.o $(LDFLAGS_A)
-
-test: pngtest pngtest-static
-	@echo ""
-	@echo "   Running pngtest dynamically linked with $(LIBSO):"
-	@echo ""
-	./pngtest
-	@echo ""
-	@echo "   Running pngtest statically linked with libpng.a:"
-	@echo ""
-	./pngtest-static
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) -Wl, -rpath,$(DL) -Wl,-rpath,$(ZLIBLIB) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	$(CC) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngout.png libpng-config \
-	$(LIBSO) $(LIBSOMAJ)* pngtest-static pngtesti \
-	libpng.pc pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h
diff --git a/extern/libpng/include/scripts/makefile.mips b/extern/libpng/include/scripts/makefile.mips
deleted file mode 100644
index 179d3850b6..0000000000
--- a/extern/libpng/include/scripts/makefile.mips
+++ /dev/null
@@ -1,94 +0,0 @@
-# makefile for libpng
-# Copyright (C) Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# where make install puts libpng.a and png.h
-prefix=/usr/local
-INCPATH=$(prefix)/include
-LIBPATH=$(prefix)/lib
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-CC=cc
-CFLAGS=-I../zlib -O -systype sysv -DSYSV -w -Dmips
-#CFLAGS=-O
-LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
-
-#RANLIB=ranlib
-RANLIB=echo
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-all: libpng.a pngtest
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	ar rc $@  $(OBJS)
-	$(RANLIB) $@
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install: libpng.a
-	-@mkdir $(DESTDIR)$(INCPATH)
-	-@mkdir $(DESTDIR)$(INCPATH)/libpng
-	-@mkdir $(DESTDIR)$(LIBPATH)
-	-@rm -f $(DESTDIR)$(INCPATH)/png.h
-	-@rm -f $(DESTDIR)$(INCPATH)/pngconf.h
-	-@rm -f $(DESTDIR)$(INCPATH)/pnglibconf.h
-	cp png.h $(DESTDIR)$(INCPATH)/libpng
-	cp pngconf.h $(DESTDIR)$(INCPATH)/libpng
-	cp pnglibconf.h $(DESTDIR)$(INCPATH)/libpng
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/png.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pngconf.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pnglibconf.h
-	(cd $(DESTDIR)$(INCPATH); ln -f -s libpng/* .)
-	cp libpng.a $(DESTDIR)$(LIBPATH)
-	chmod 644 $(DESTDIR)$(LIBPATH)/libpng.a
-
-clean:
-	rm -f *.o libpng.a pngtest pngout.png pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.msc b/extern/libpng/include/scripts/makefile.msc
deleted file mode 100644
index baa863dad9..0000000000
--- a/extern/libpng/include/scripts/makefile.msc
+++ /dev/null
@@ -1,95 +0,0 @@
-# makefile for libpng
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-# Copyright (C) 2006, 2009 Glenn Randers-Pehrson
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-#
-# Assumes that zlib.lib, zconf.h, and zlib.h have been copied to ..\zlib
-
-# -------- Microsoft C 5.1 and later, does not use assembler code --------
-MODEL=L
-CFLAGS=-Oait -Gs -nologo -W3 -A$(MODEL) -I..\zlib
-#-Ox generates bad code with MSC 5.1
-CC=cl
-LD=link
-LDFLAGS=/e/st:0x1500/noe
-O=.obj
-
-#uncomment next to put error messages in a file
-ERRFILE= >> pngerrs
-
-# variables
-OBJS1 = png$(O) pngset$(O) pngget$(O) pngrutil$(O) pngtrans$(O) pngwutil$(O)
-OBJS2 = pngmem$(O) pngpread$(O) pngread$(O) pngerror$(O) pngwrite$(O)
-OBJS3 = pngrtran$(O) pngwtran$(O) pngrio$(O) pngwio$(O)
-
-all: libpng.lib
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngget$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngmem$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngrio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngwio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-libpng.lib: $(OBJS1) $(OBJS2) $(OBJS3)
-	del libpng.lib
-	lib libpng $(OBJS1);
-	lib libpng $(OBJS2);
-	lib libpng $(OBJS3);
-
-pngtest$(O): png.h pngconf.h pnglibconf.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngtest.exe: pngtest.obj libpng.lib
-	$(LD) $(LDFLAGS) pngtest.obj,,,libpng.lib ..\zlib\zlib.lib ;
-
-test: pngtest.exe
-	pngtest
-
-# End of makefile for libpng
-
diff --git a/extern/libpng/include/scripts/makefile.ne12bsd b/extern/libpng/include/scripts/makefile.ne12bsd
deleted file mode 100644
index c447f12034..0000000000
--- a/extern/libpng/include/scripts/makefile.ne12bsd
+++ /dev/null
@@ -1,50 +0,0 @@
-# makefile for libpng for NetBSD for the standard
-# make obj && make depend && make && make test
-# make includes && make install
-# Copyright (C) 2002 Patrick R.L. Welche
-# Copyright (C) 2007, 2009 Glenn Randers-Pehrson
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# You should also run makefile.netbsd
-
-LOCALBASE?=/usr/local
-LIBDIR=	${LOCALBASE}/lib
-MANDIR= ${LOCALBASE}/man
-INCSDIR=${LOCALBASE}/include/libpng15
-
-LIB=	png15
-SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.5.10
-SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
-	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
-	pngwtran.c pngmem.c pngerror.c pngpread.c
-INCS=	png.h pngconf.h pnglibconf.h
-MAN=	libpng.3 libpngpf.3 png.5
-
-CPPFLAGS+=-I${.CURDIR}
-
-# We should be able to do something like this instead of the manual
-# uncommenting, but it core dumps for me at the moment:
-# .if ${MACHINE_ARCH} == "i386"
-#   MKLINT= no
-# .endif
-
-CLEANFILES+=pngtest.o pngtest pnglibconf.h
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-pngtest.o:	pngtest.c
-	${CC} -c ${CPPFLAGS} ${CFLAGS} ${.ALLSRC} -o ${.TARGET}
-
-pngtest:	pngtest.o libpng.a
-	${CC} ${LDFLAGS} ${.ALLSRC} -o${.TARGET} -lz -lm
-
-test:	pngtest
-	cd ${.CURDIR} && ${.OBJDIR}/pngtest
-
-.include <bsd.lib.mk>
diff --git a/extern/libpng/include/scripts/makefile.netbsd b/extern/libpng/include/scripts/makefile.netbsd
deleted file mode 100644
index d154810640..0000000000
--- a/extern/libpng/include/scripts/makefile.netbsd
+++ /dev/null
@@ -1,50 +0,0 @@
-# makefile for libpng for NetBSD for the standard
-# make obj && make depend && make && make test
-# make includes && make install
-# Copyright (C) 2002 Patrick R.L. Welche
-# Copyright (C) 2007-2009 Glenn Randers-Pehrson
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# You should also run makefile.ne15bsd
-
-LOCALBASE?=/usr/local
-LIBDIR=	${LOCALBASE}/lib
-MANDIR= ${LOCALBASE}/man
-INCSDIR=${LOCALBASE}/include
-
-LIB=	png
-SHLIB_MAJOR=	15
-SHLIB_MINOR=	1.5.10
-SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
-	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
-	pngwtran.c pngmem.c pngerror.c pngpread.c
-INCS=	png.h pngconf.h pnglibconf.h
-MAN=	libpng.3 libpngpf.3 png.5
-
-CPPFLAGS+=-I${.CURDIR}
-
-# We should be able to do something like this instead of the manual
-# uncommenting, but it core dumps for me at the moment:
-# .if ${MACHINE_ARCH} == "i386"
-#   MKLINT= no
-# .endif
-
-CLEANFILES+=pngtest.o pngtest pnglibconf.h
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-pngtest.o:	pngtest.c
-	${CC} -c ${CPPFLAGS} ${CFLAGS} ${.ALLSRC} -o ${.TARGET}
-
-pngtest:	pngtest.o libpng.a
-	${CC} ${LDFLAGS} ${.ALLSRC} -o${.TARGET} -lz -lm
-
-test:	pngtest
-	cd ${.CURDIR} && ${.OBJDIR}/pngtest
-
-.include <bsd.lib.mk>
diff --git a/extern/libpng/include/scripts/makefile.openbsd b/extern/libpng/include/scripts/makefile.openbsd
deleted file mode 100644
index 3a1b84ea31..0000000000
--- a/extern/libpng/include/scripts/makefile.openbsd
+++ /dev/null
@@ -1,82 +0,0 @@
-# makefile for libpng
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-# Copyright (C) 2007-2009 Glenn Randers-Pehrson
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-PREFIX?= /usr/local
-LIBDIR=	${PREFIX}/lib
-MANDIR= ${PREFIX}/man/cat
-
-SHLIB_MAJOR=	15
-SHLIB_MINOR=	1.5.10
-
-LIB=	png
-SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
-	pngread.c pngrio.c pngrtran.c pngrutil.c pngset.c pngtrans.c \
-	pngwio.c pngwrite.c pngwtran.c pngwutil.c
-
-HDRS=	png.h pngconf.h pnglibconf.h
-
-CFLAGS+= -W -Wall
-CPPFLAGS+= -I${.CURDIR}
-
-NOPROFILE= Yes
-
-CLEANFILES+= pngtest.o pngtest pnglibconf.h
-
-MAN=	libpng.3 libpngpf.3 png.5
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO \
-       libpng-manual.txt
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-pngtest.o:	pngtest.c
-	${CC} ${CPPFLAGS} ${CFLAGS} -c ${.ALLSRC} -o ${.TARGET}
-
-pngtest:	pngtest.o
-	${CC} ${LDFLAGS} ${.ALLSRC} -o ${.TARGET} -L${.OBJDIR} -lpng -lz -lm
-
-test:	pngtest
-	cd ${.OBJDIR} && env \
-		LD_LIBRARY_PATH="${.OBJDIR}" ${.OBJDIR}/pngtest
-
-beforeinstall:
-	if [ ! -d ${DESTDIR}${PREFIX}/include/libpng ]; then \
-	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${PREFIX}/include; \
-	fi
-	if [ ! -d ${DESTDIR}${LIBDIR} ]; then \
-	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${LIBDIR}; \
-	fi
-	if [ ! -d ${DESTDIR}${LIBDIR}/debug ]; then \
-	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${LIBDIR}/debug; \
-	fi
-	if [ ! -d ${DESTDIR}${MANDIR}3 ]; then \
-	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${MANDIR}3; \
-	fi
-	if [ ! -d ${DESTDIR}${MANDIR}5 ]; then \
-	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${MANDIR}5; \
-	fi
-	if [ ! -d ${DESTDIR}${PREFIX}/share/doc/png ]; then \
-	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${PREFIX}/share/doc/png; \
-	fi
-
-afterinstall:
-	@rm -f ${DESTDIR}${LIBDIR}/libpng_pic.a
-	@rm -f ${DESTDIR}${LIBDIR}/debug/libpng.a
-	@rm -f ${DESTDIR}${PREFIX}/include/png.h
-	@rm -f ${DESTDIR}${PREFIX}/include/pngconf.h
-	@rm -f ${DESTDIR}${PREFIX}/include/pnglibconf.h
-	@rmdir ${DESTDIR}${LIBDIR}/debug 2>/dev/null || true
-	${INSTALL} ${INSTALL_COPY} -o ${SHAREOWN} -g ${SHAREGRP} \
-		-m ${NONBINMODE} ${HDRS} ${DESTDIR}${PREFIX}/include
-	${INSTALL} ${INSTALL_COPY} -o ${SHAREOWN} -g ${SHAREGRP} \
-		-m ${NONBINMODE} ${HDRS} ${DESTDIR}${PREFIX}/include
-	${INSTALL} ${INSTALL_COPY} -o ${SHAREOWN} -g ${SHAREGRP} \
-		-m ${NONBINMODE} ${DOCS} ${DESTDIR}${PREFIX}/share/doc/png
-
-.include <bsd.lib.mk>
diff --git a/extern/libpng/include/scripts/makefile.sco b/extern/libpng/include/scripts/makefile.sco
deleted file mode 100644
index 0aad789a98..0000000000
--- a/extern/libpng/include/scripts/makefile.sco
+++ /dev/null
@@ -1,218 +0,0 @@
-# makefile for SCO OSr5  ELF and Unixware 7 with Native cc
-# Contributed by Mike Hopkirk (hops@sco.com) modified from Makefile.lnx
-#   force ELF build dynamic linking, SONAME setting in lib and RPATH in app
-# Copyright (C) 2002, 2006, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1998 Greg Roelofs
-# Copyright (C) 1996, 1997 Andreas Dilger
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME = libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-CC=cc
-AR_RC=ar rc
-MKDIR_P=mkdir
-LN_SF=ln -f -s
-RANLIB=echo
-RM_F=/bin/rm -f
-
-# where make install puts libpng.a, $(OLDSO)*, and png.h
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-ZLIBLIB=../zlib
-ZLIBINC=../zlib
-
-CFLAGS= -dy -belf -I$(ZLIBINC) -O3
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng15 -lz -lm
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -KPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo ccopts=\"-belf\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	$(CC) -G  -Wl,-h,$(LIBSOMAJ) -o $(LIBSOMAJ) \
-	 $(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	LD_RUN_PATH=.:$(ZLIBLIB) $(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	-@$(RM_F) $(DI)/png.h
-	-@$(RM_F) $(DI)/pngconf.h
-	-@$(RM_F) $(DI)/pnglibconf.h
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) $(CFLAGS) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	$(CC) $(CFLAGS) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngout.png libpng-config \
-	$(LIBSO) $(LIBSOMAJ)* pngtest-static pngtesti \
-	pnglibconf.h libpng.pc
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.sggcc b/extern/libpng/include/scripts/makefile.sggcc
deleted file mode 100644
index 1611638ba6..0000000000
--- a/extern/libpng/include/scripts/makefile.sggcc
+++ /dev/null
@@ -1,228 +0,0 @@
-# makefile for libpng.a and libpng15.so, SGI IRIX with 'cc'
-# Copyright (C) 2001-2002, 2006, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME=libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-AR_RC=ar rc
-CC=gcc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=echo
-RM_F=/bin/rm -f
-
-# Where make install puts libpng.a, libpng15.so, and libpng15/png.h
-# Prefix must be a full pathname.
-
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-#ZLIBLIB=/usr/local/lib32
-#ZLIBINC=/usr/local/include
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-ZLIBLIB=../zlib
-ZLIBINC=../zlib
-
-# ABI can be blank to use default for your system, -32, -o32, -n32, or -64
-# See "man abi".  zlib must be built with the same ABI.
-ABI=
-
-WARNMORE= # -g -DPNG_DEBUG=5
-CFLAGS=$(ABI) -I$(ZLIBINC) -O $(WARNMORE) -fPIC -mabi=n32
-LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm
-LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
-	-set_version sgi$(PNGMAJ).0
-# See "man dso" for info about shared objects
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-#LIBPATH=$(exec_prefix)/lib32
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS =  png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-all: libpng.a pngtest shared libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-shared: $(LIBSOMAJ)
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo ccopts=\"$(ABI)\"; \
-	echo cppflags=\"\"; \
-	echo ldopts=\"$(ABI)\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libdir=\"$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJS)
-	$(LDSHARED) -o $@ $(OBJS)
-	$(RM_F) $(LIBSO) $(LIBSOMAJ)
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	echo
-	echo Testing local static library.
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) \
-	   -rpath $(ZLIBLIB):$(DL) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) \
-	   -rpath $(ZLIBLIB):`$(BINPATH)/$(LIBNAME)-config --libdir` \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) libpng.a pngtest pngtesti pngout.png libpng.pc \
-	so_locations libpng-config $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.sgi b/extern/libpng/include/scripts/makefile.sgi
deleted file mode 100644
index 83db59f817..0000000000
--- a/extern/libpng/include/scripts/makefile.sgi
+++ /dev/null
@@ -1,229 +0,0 @@
-# makefile for libpng.a and libpng15.so, SGI IRIX with 'cc'
-# Copyright (C) 2001-2002, 2006, 2007, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME=libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-AR_RC=ar rc
-CC=cc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=echo
-RM_F=/bin/rm -f
-
-# Where make install puts libpng.a, libpng15.so, and libpng15/png.h
-# Prefix must be a full pathname.
-
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-#ZLIBLIB=/usr/local/lib32
-#ZLIBINC=/usr/local/include
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-ZLIBLIB=../zlib
-ZLIBINC=../zlib
-
-# ABI can be blank to use default for your system, -32, -o32, -n32, or -64
-# See "man abi".  zlib must be built with the same ABI.
-ABI=
-
-WARNMORE=-fullwarn
-# Note: -KPIC is the default anyhow
-#CFLAGS= $(ABI) -I$(ZLIBINC) -O $(WARNMORE) -KPIC # -g -DPNG_DEBUG=5
-CFLAGS=$(ABI) -I$(ZLIBINC) -O $(WARNMORE)
-LDFLAGS_A=$(ABI) -L. -L$(ZLIBLIB) -lpng15 -lz -lm
-LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm
-LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
-	-set_version sgi$(PNGMAJ).0
-# See "man dso" for info about shared objects
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-#LIBPATH=$(exec_prefix)/lib32
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS =  png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-all: libpng.a pngtest shared libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo ccopts=\"$(ABI)\"; \
-	echo ldopts=\"$(ABI)\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libdir=\"$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJS)
-	$(LDSHARED) -o $@ $(OBJS)
-	$(RM_F) $(LIBSO) $(LIBSOMAJ)
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	echo
-	echo Testing local static library.
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) \
-	   -rpath $(ZLIBLIB):$(DL) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) \
-	   -rpath $(ZLIBLIB):`$(BINPATH)/$(LIBNAME)-config --libdir` \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png libpng.pc libpng-config \
-	$(LIBSO) $(LIBSOMAJ)* \
-	so_locations pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.so9 b/extern/libpng/include/scripts/makefile.so9
deleted file mode 100644
index 615c2e3458..0000000000
--- a/extern/libpng/include/scripts/makefile.so9
+++ /dev/null
@@ -1,239 +0,0 @@
-# makefile for libpng on Solaris 9 (beta) with Forte cc
-# Updated by Chad Schrock for Solaris 9
-# Contributed by William L. Sebok, based on makefile.linux
-# Copyright (C) 2002, 2006, 2008, 2010-2011 Glenn Randers-Pehrson
-# Copyright (C) 1998-2001 Greg Roelofs
-# Copyright (C) 1996-1997 Andreas Dilger
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-PNGMAJ = 15
-LIBNAME = libpng15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-# gcc 2.95 doesn't work.
-CC=cc
-AR_RC=ar rc
-MKDIR_P=mkdir -p
-LN_SF=ln -f -s
-RANLIB=echo
-RM_F=/bin/rm -f
-
-# Where make install puts libpng.a, $(OLDSO)*, and png.h
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-# Changing these to ../zlib poses a security risk.  If you want
-# to have zlib in an adjacent directory, specify the full path instead of "..".
-#ZLIBLIB=../zlib
-#ZLIBINC=../zlib
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-#Use the preinstalled zlib that comes with Solaris 9:
-ZLIBLIB=/usr/lib
-ZLIBINC=/usr/include
-
-#WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-#CFLAGS=-I$(ZLIBINC) -W -Wall -O3 $(WARNMORE) -g -DPNG_DEBUG=5 -DPNG_NO_MMX_CODE
-CFLAGS=-I$(ZLIBINC) -O3 -DPNG_NO_MMX_CODE
-LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng15 -lz -lm
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -KPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	@case "`type ld`" in *ucb*) \
-	echo; \
-	echo '## WARNING:'; \
-	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
-	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
-	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
-	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
-	echo '## at all.  If it is, things are likely to break because of'; \
-	echo '## the libucb dependency that is created.'; \
-	echo; \
-	;; \
-	esac
-	$(LD) -G -h $(LIBSOMAJ) \
-	 -o $(LIBSOMAJ) $(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   -L$(DL) -L$(ZLIBLIB)  -R$(ZLIBLIB) -R$(DL)
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   -L$(ZLIBLIB) -R$(ZLIBLIB)
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
-	libpng-config $(LIBSO) $(LIBSOMAJ)* \
-	libpng.pc pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.solaris b/extern/libpng/include/scripts/makefile.solaris
deleted file mode 100644
index 24bd61033c..0000000000
--- a/extern/libpng/include/scripts/makefile.solaris
+++ /dev/null
@@ -1,236 +0,0 @@
-# makefile for libpng on Solaris 2.x with gcc
-# Copyright (C) 2004, 2006-2008, 2010-2011 Glenn Randers-Pehrson
-# Contributed by William L. Sebok, based on makefile.linux
-# Copyright (C) 1998 Greg Roelofs
-# Copyright (C) 1996, 1997 Andreas Dilger
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME = libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-AR_RC=ar rc
-CC=gcc
-MKDIR_P=mkdir -p
-LN_SF=ln -f -s
-RANLIB=echo
-RM_F=/bin/rm -f
-
-# Where make install puts libpng.a, libpng15.so*, and png.h
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-# Changing these to ../zlib poses a security risk.  If you want
-# to have zlib in an adjacent directory, specify the full path instead of "..".
-#ZLIBLIB=../zlib
-#ZLIBINC=../zlib
-
-ZLIBLIB=/usr/local/lib
-ZLIBINC=/usr/local/include
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) -W -Wall -O \
-	# $(WARNMORE) -g -DPNG_DEBUG=5
-LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng15 -lz -lm
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -fPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo cppflags=\"\"; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	@case "`type ld`" in *ucb*) \
-	echo; \
-	echo '## WARNING:'; \
-	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
-	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
-	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
-	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
-	echo '## at all.  If it is, things are likely to break because of'; \
-	echo '## the libucb dependency that is created.'; \
-	echo; \
-	;; \
-	esac
-	$(LD) -G -h $(LIBSOMAJ) \
-	 -o $(LIBSOMAJ) $(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   -L$(DL) -L$(ZLIBLIB) -R$(ZLIBLIB) -R$(DL)
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   -L$(ZLIBLIB) -R$(ZLIBLIB)
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
-	libpng-config $(LIBSO) $(LIBSOMAJ)* \
-	libpng.pc pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.solaris-x86 b/extern/libpng/include/scripts/makefile.solaris-x86
deleted file mode 100644
index 76467622a8..0000000000
--- a/extern/libpng/include/scripts/makefile.solaris-x86
+++ /dev/null
@@ -1,236 +0,0 @@
-# makefile for libpng on Solaris 2.x with gcc
-# Copyright (C) 2004, 2006-2008, 2010-2011 Glenn Randers-Pehrson
-# Contributed by William L. Sebok, based on makefile.linux
-# Copyright (C) 1998 Greg Roelofs
-# Copyright (C) 1996, 1997 Andreas Dilger
-
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Library name:
-LIBNAME = libpng15
-PNGMAJ = 15
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-
-# Utilities:
-AR_RC=ar rc
-CC=gcc
-MKDIR_P=mkdir -p
-LN_SF=ln -f -s
-RANLIB=echo
-RM_F=/bin/rm -f
-
-# Where make install puts libpng.a, libpng15.so*, and png.h
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located
-# Changing these to ../zlib poses a security risk.  If you want
-# to have zlib in an adjacent directory, specify the full path instead of "..".
-#ZLIBLIB=../zlib
-#ZLIBINC=../zlib
-
-ZLIBLIB=/usr/local/lib
-ZLIBINC=/usr/local/include
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) -W -Wall -O \
-	# $(WARNMORE) -g -DPNG_DEBUG=5
-LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng15 -lz -lm
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -fPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng15!-lpng15\ -lz\ -lm! > libpng.pc
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo cppflags=\""; \
-	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo libs=\"-lpng15 -lz -lm\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL)
-	@case "`type ld`" in *ucb*) \
-	echo; \
-	echo '## WARNING:'; \
-	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
-	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
-	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
-	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
-	echo '## at all.  If it is, things are likely to break because of'; \
-	echo '## the libucb dependency that is created.'; \
-	echo; \
-	;; \
-	esac
-	$(LD) -G -h $(LIBSOMAJ) \
-	 -o $(LIBSOMAJ) $(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   -L$(DL) -L$(ZLIBLIB) -R$(ZLIBLIB) -R$(DL)
-	./pngtestd pngtest.png
-
-test-installed:
-	echo
-	echo Testing installed dynamic shared library.
-	$(CC) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
-	   -L$(ZLIBLIB) -R$(ZLIBLIB)
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
-	libpng-config $(LIBSO) $(LIBSOMAJ)* \
-	libpng.pc pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.std b/extern/libpng/include/scripts/makefile.std
deleted file mode 100644
index a04dbb856b..0000000000
--- a/extern/libpng/include/scripts/makefile.std
+++ /dev/null
@@ -1,123 +0,0 @@
-# makefile for libpng
-# Copyright (C) 2002, 2006 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# where make install puts libpng.a and png.h
-prefix=/usr/local
-INCPATH=$(prefix)/include
-LIBPATH=$(prefix)/lib
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-# Where the zlib library and include files are located
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-ZLIBLIB=../zlib
-ZLIBINC=../zlib
-
-CC=cc
-AR_RC=ar rc
-MKDIR_P=mkdir
-LN_SF=ln -sf
-RANLIB=ranlib
-RM_F=rm -f
-AWK = awk
-SED = sed
-CPP = $(CC) -E
-ECHO = echo
-
-DFNFLAGS = # DFNFLAGS contains -D options to use in the libpng build
-CFLAGS=-I$(ZLIBINC) -O # -g -DPNG_DEBUG=5
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-all: libpng.a pngtest
-
-# The standard pnglibconf.h exists as scripts/pnglibconf.h.prebuilt,
-# copy this if the following doesn't work.
-pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
-	$(RM_F) $@ dfn?.out
-	$(AWK) -f scripts/options.awk out=dfn1.out version=search pngconf.h\
-	    scripts/pnglibconf.dfa $(DFA_XTRA) 1>&2
-	$(AWK) -f scripts/options.awk out=dfn2.out dfn1.out 1>&2
-	cp dfn2.out $@
-	$(RM_F) dfn?.out
-
-pnglibconf.h: pnglibconf.dfn
-	$(RM_F) $@ dfn.c dfn?.out
-	$(ECHO) '#include "pnglibconf.dfn"' >dfn.c
-	$(CPP) $(DFNFLAGS) dfn.c >dfn1.out
-	$(SED) -n -e 's|^.*PNG_DEFN_MAGIC *-\(.*\)- *PNG_DEFN_END.*$$|\1|p'\
-	    dfn1.out >dfn2.out
-	$(SED) -e 's| *PNG_JOIN *||g' -e 's| *$$||' dfn2.out >dfn3.out
-	cp dfn3.out $@
-	$(RM_F) dfn.c dfn?.out
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@  $(OBJS)
-	$(RANLIB) $@
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install: libpng.a pnglibconf.h
-	-@$(MKDIR_P) $(DESTDIR)$(INCPATH)
-	-@$(MKDIR_P) $(DESTDIR)$(INCPATH)/libpng
-	-@$(MKDIR_P) $(DESTDIR)$(LIBPATH)
-	-@$(RM_F) $(DESTDIR)$(INCPATH)/png.h
-	-@$(RM_F) $(DESTDIR)$(INCPATH)/pngconf.h
-	-@$(RM_F) $(DESTDIR)$(INCPATH)/pnglibconf.h
-	cp png.h $(DESTDIR)$(INCPATH)/libpng
-	cp pngconf.h $(DESTDIR)$(INCPATH)/libpng
-	cp pnglibconf.h $(DESTDIR)$(INCPATH)/libpng
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/png.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pngconf.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pnglibconf.h
-	(cd $(DESTDIR)$(INCPATH); ln -f -s libpng/* .)
-	cp libpng.a $(DESTDIR)$(LIBPATH)
-	chmod 644 $(DESTDIR)$(LIBPATH)/libpng.a
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.* dfn.c dfn?.out
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.sunos b/extern/libpng/include/scripts/makefile.sunos
deleted file mode 100644
index 383954987e..0000000000
--- a/extern/libpng/include/scripts/makefile.sunos
+++ /dev/null
@@ -1,107 +0,0 @@
-# makefile for libpng
-# Copyright (C) 2002, 2006 Glenn Randers-Pehrson
-# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# where make install puts libpng.a and png.h
-prefix=/usr/local
-INCPATH=$(prefix)/include
-LIBPATH=$(prefix)/lib
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-# Where the zlib library and include files are located
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-ZLIBLIB=../zlib
-ZLIBINC=../zlib
-
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow -Wconversion \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes
-
-CC=gcc
-AR_RC=ar rc
-MKDIR_P=mkdir -p
-LN_SF=ln -f -s
-RANLIB=ranlib
-RM_F=/bin/rm -f
-
-CFLAGS=-I$(ZLIBINC) -O # $(WARNMORE) -DPNG_DEBUG=5
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-all: libpng.a pngtest
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@  $(OBJS)
-	$(RANLIB) $@
-
-pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install: libpng.a
-	-@$(MKDIR_P) $(DESTDIR)$(INCPATH)
-	-@$(MKDIR_P) $(DESTDIR)$(INCPATH)/libpng
-	-@$(MKDIR_P) $(DESTDIR)$(LIBPATH)
-	-@$(RM_F) $(DESTDIR)$(INCPATH)/png.h
-	-@$(RM_F) $(DESTDIR)$(INCPATH)/pngconf.h
-	-@$(RM_F) $(DESTDIR)$(INCPATH)/pnglibconf.h
-	cp png.h $(DESTDIR)$(INCPATH)/libpng
-	cp pngconf.h $(DESTDIR)$(INCPATH)/libpng
-	cp pnglibconf.h $(DESTDIR)$(INCPATH)/libpng
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/png.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pngconf.h
-	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pnglibconf.h
-	(cd $(DESTDIR)$(INCPATH); $(LN_SF) libpng/* .)
-	cp libpng.a $(DESTDIR)$(LIBPATH)
-	chmod 644 $(DESTDIR)$(LIBPATH)/libpng.a
-
-clean:
-	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/include/scripts/makefile.tc3 b/extern/libpng/include/scripts/makefile.tc3
deleted file mode 100644
index 462c47fece..0000000000
--- a/extern/libpng/include/scripts/makefile.tc3
+++ /dev/null
@@ -1,93 +0,0 @@
-# Makefile for libpng
-# TurboC/C++ (Note: All modules are compiled in C mode)
-
-# To use, do "make -fmakefile.tc3"
-
-# ----- Turbo C 3.00 (can be modified to work with earlier versions) -----
-
-MODEL=l
-CFLAGS=-O2 -Z -m$(MODEL) -I..\zlib
-#CFLAGS=-D_NO_PROTO -O2 -Z -m$(MODEL) -I..\zlib  # Turbo C older than 3.00
-CC=tcc
-LD=tcc
-LIB=tlib
-LDFLAGS=-m$(MODEL) -L..\zlib
-O=.obj
-E=.exe
-
-# variables
-OBJS1 = png$(O) pngset$(O) pngget$(O) pngrutil$(O) pngtrans$(O) pngwutil$(O)
-OBJS2 = pngmem$(O) pngpread$(O) pngread$(O) pngerror$(O) pngwrite$(O)
-OBJS3 = pngrtran$(O) pngwtran$(O) pngrio$(O) pngwio$(O)
-OBJSL1 = +png$(O) +pngset$(O) +pngget$(O) +pngrutil$(O) +pngtrans$(O)
-OBJSL2 = +pngwutil$(O) +pngmem$(O) +pngpread$(O) +pngread$(O) +pngerror$(O)
-OBJSL3 = +pngwrite$(O) +pngrtran$(O) +pngwtran$(O) +pngrio$(O) +pngwio$(O)
-
-all: libpng$(MODEL).lib pngtest$(E)
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-pngtest: pngtest$(E)
-
-test: pngtest$(E)
-	pngtest$(E)
-
-png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CFLAGS) $*.c
-
-pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CFLAGS) $*.c
-
-pngget$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CFLAGS) $*.c
-
-pngread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CFLAGS) $*.c
-
-pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CFLAGS) $*.c
-
-pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CFLAGS) $*.c
-
-pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CFLAGS) $*.c
-
-pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c
-
-pngmem$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c
-
-pngrio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c
-
-pngwio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c
-
-pngtest$(O): png.h pngconf.h pnglibconf.h
-	$(CC) -c $(CFLAGS) $*.c
-
-pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c
-
-pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c
-
-pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c
-
-pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c
-
-libpng$(MODEL).lib: $(OBJS1) $(OBJS2) $(OBJS3)
-	$(LIB) libpng$(MODEL) +$(OBJSL1)
-	$(LIB) libpng$(MODEL) +$(OBJSL2)
-	$(LIB) libpng$(MODEL) +$(OBJSL3)
-
-pngtest$(E): pngtest$(O) libpng$(MODEL).lib
-	$(LD) $(LDFLAGS) pngtest.obj libpng$(MODEL).lib zlib_$(MODEL).lib
-
-# End of makefile for libpng
diff --git a/extern/libpng/include/scripts/makefile.vcwin32 b/extern/libpng/include/scripts/makefile.vcwin32
deleted file mode 100644
index 6bfeac03f7..0000000000
--- a/extern/libpng/include/scripts/makefile.vcwin32
+++ /dev/null
@@ -1,108 +0,0 @@
-# makefile for libpng
-# Copyright (C) 1998 Tim Wegner
-# Copyright (C) 2006,2009,2011 Glenn Randers-Pehrson
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-#
-# Assumes that zlib.lib, zconf.h, and zlib.h have been copied to ..\zlib
-# To use, do "nmake /f scripts\makefile.vcwin32"
-
-# -------- Microsoft Visual C++ 2.0 and later, no assembler code --------
-
-# Compiler, linker, librarian, and other tools
-CC = cl
-LD = link
-AR = lib
-CFLAGS  = -nologo -D_CRT_SECURE_NO_DEPRECATE -MD -O2 -W3 -I..\zlib
-LDFLAGS = -nologo
-ARFLAGS = -nologo
-RM = del
-
-# File extensions
-O=.obj
-
-#uncomment next to put error messages in a file
-#ERRFILE= >> pngerrs.log
-
-# Variables
-OBJS1 = png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O)
-OBJS2 = pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O)
-OBJS3 = pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
-OBJS  = $(OBJS1) $(OBJS2) $(OBJS3)
-
-# Targets
-all: libpng.lib
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts\pnglibconf.h.prebuilt
-       copy scripts\pnglibconf.h.prebuilt $@
-
-png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngget$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngmem$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngrio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngwio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-libpng.lib: $(OBJS)
-	-$(RM) $@
-	$(AR) $(ARFLAGS) -out:$@ $(OBJS) $(ERRFILE)
-
-pngtest$(O): png.h pngconf.h pnglibconf.h
-	$(CC) -c $(CFLAGS) $*.c $(ERRFILE)
-
-pngtest.exe: pngtest$(O) libpng.lib
-	$(LD) $(LDFLAGS) -out:$@ pngtest$(O) libpng.lib ..\zlib\zlib.lib $(ERRFILE)
-
-test: pngtest.exe
-	pngtest
-
-clean:
-	-$(RM) *$(O)
-	-$(RM) libpng.lib
-	-$(RM) pnglibconf.h
-	-$(RM) pngtest.exe
-	-$(RM) pngout.png
-
-# End of makefile for libpng
-
diff --git a/extern/libpng/include/scripts/makevms.com b/extern/libpng/include/scripts/makevms.com
deleted file mode 100644
index f6c326103c..0000000000
--- a/extern/libpng/include/scripts/makevms.com
+++ /dev/null
@@ -1,142 +0,0 @@
-$! make libpng under VMS
-$!
-$!
-$! Check for MMK/MMS
-$!
-$! This procedure accepts one parameter (contrib), which causes it to build
-$! the programs from the contrib directory instead of libpng.
-$!
-$ p1 = f$edit(p1,"UPCASE")
-$ if p1 .eqs. "CONTRIB"
-$ then
-$   set def [.contrib.gregbook]
-$   @makevms
-$   set def [-.pngminus]
-$   @makevms
-$   set def [--]
-$   exit
-$ endif
-$ Make = ""
-$ If F$Search ("Sys$System:MMS.EXE") .nes. "" Then Make = "MMS"
-$ If F$Type (MMK) .eqs. "STRING" Then Make = "MMK"
-$!
-$! Look for the compiler used
-$!
-$ zlibsrc = "[-.zlib]"
-$ ccopt="/include=''zlibsrc'"
-$ if f$getsyi("HW_MODEL").ge.1024
-$ then
-$  ccopt = "/prefix=all"+ccopt
-$  comp  = "__decc__=1"
-$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$ else
-$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
-$   then
-$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
-$     then
-$      comp  = "__gcc__=1"
-$      CC :== GCC
-$     else
-$      comp = "__vaxc__=1"
-$     endif
-$   else
-$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
-$    ccopt = "/decc/prefix=all"+ccopt
-$    comp  = "__decc__=1"
-$  endif
-$ endif
-$!
-$! Build the thing plain or with mms/mmk
-$!
-$ write sys$output "Compiling Libpng sources ..."
-$ if make.eqs.""
-$  then
-$   dele pngtest.obj;*
-$   CALL MAKE png.OBJ "cc ''CCOPT' png" -
-	png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngset.OBJ "cc ''CCOPT' pngset" -
-	pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngget.OBJ "cc ''CCOPT' pngget" -
-	pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngread.OBJ "cc ''CCOPT' pngread" -
-	pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngpread.OBJ "cc ''CCOPT' pngpread" -
-	pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngrtran.OBJ "cc ''CCOPT' pngrtran" -
-	pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngrutil.OBJ "cc ''CCOPT' pngrutil" -
-	pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngerror.OBJ "cc ''CCOPT' pngerror" -
-	pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngmem.OBJ "cc ''CCOPT' pngmem" -
-	pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngrio.OBJ "cc ''CCOPT' pngrio" -
-	pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngwio.OBJ "cc ''CCOPT' pngwio" -
-	pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngtrans.OBJ "cc ''CCOPT' pngtrans" -
-	pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngwrite.OBJ "cc ''CCOPT' pngwrite" -
-	pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngwtran.OBJ "cc ''CCOPT' pngwtran" -
-	pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   CALL MAKE pngwutil.OBJ "cc ''CCOPT' pngwutil" -
-	pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-$   write sys$output "Building Libpng ..."
-$   CALL MAKE libpng.OLB "lib/crea libpng.olb *.obj" *.OBJ
-$   write sys$output "Building pngtest..."
-$   CALL MAKE pngtest.OBJ "cc ''CCOPT' pngtest" -
-	pngtest.c png.h pngconf.h pnglibconf.h
-$   call make pngtest.exe -
-	"LINK pngtest,libpng.olb/lib,''zlibsrc'libz.olb/lib" -
-	pngtest.obj libpng.olb
-$   write sys$output "Testing Libpng..."
-$   run pngtest
-$  else
-$   if f$search("DESCRIP.MMS") .eqs. "" then copy/nolog [.SCRIPTS]DESCRIP.MMS []
-$   'make'/macro=('comp',zlibsrc='zlibsrc')
-$  endif
-$ write sys$output "Libpng build completed"
-$ exit
-$!
-$!
-$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
-$ V = 'F$Verify(0)
-$! P1 = What we are trying to make
-$! P2 = Command to make it
-$! P3 - P8  What it depends on
-$
-$ If F$Search(P1) .Eqs. "" Then Goto Makeit
-$ Time = F$CvTime(F$File(P1,"RDT"))
-$arg=3
-$Loop:
-$       Argument = P'arg
-$       If Argument .Eqs. "" Then Goto Exit
-$       El=0
-$Loop2:
-$       File = F$Element(El," ",Argument)
-$       If File .Eqs. " " Then Goto Endl
-$       AFile = ""
-$Loop3:
-$       OFile = AFile
-$       AFile = F$Search(File)
-$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
-$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
-$       Goto Loop3
-$NextEL:
-$       El = El + 1
-$       Goto Loop2
-$EndL:
-$ arg=arg+1
-$ If arg .Le. 8 Then Goto Loop
-$ Goto Exit
-$
-$Makeit:
-$ VV=F$VERIFY(0)
-$ write sys$output P2
-$ 'P2
-$ VV='F$Verify(VV)
-$Exit:
-$ If V Then Set Verify
-$ENDSUBROUTINE
diff --git a/extern/libpng/include/scripts/options.awk b/extern/libpng/include/scripts/options.awk
deleted file mode 100755
index 9ef98bc8e5..0000000000
--- a/extern/libpng/include/scripts/options.awk
+++ /dev/null
@@ -1,777 +0,0 @@
-#!/bin/awk -f
-# scripts/options.awk - library build configuration control
-#
-# last changed in libpng version 1.5.7 - December 15, 2011
-#
-# Copyright (c) 1998-2011 Glenn Randers-Pehrson
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# The output of this script is written to the file given by
-# the variable 'out'.  The script is run twice, once with
-# an intermediate output file, 'options.tmp' then again on
-# that file to produce the final output:
-#
-#  awk -f scripts/options.awk out=options.tmp scripts/options.dfa 1>&2
-#  awk -f scripts/options.awk out=options.dfn options.tmp 1>&2
-#
-# Some options may be specified on the command line:
-#
-#  deb=1            Causes debugging to be output
-#  logunsupported=1 Causes all options to be recorded in the output
-#  everything=off   Causes all options to be disabled by default
-#  everything=on    Causes all options to be enabled by default
-#
-# If awk fails on your platform, try nawk instead.
-#
-# These options may also be specified in the original input file (and
-# are copied to the preprocessed file).
-
-BEGIN{
-   out="/dev/null"              # intermediate, preprocessed, file
-   pre=-1                       # preprocess (first line)
-   version="libpng version unknown" # version information
-   version_file=""              # where to find the version
-   err=0                        # in-line exit sets this
-   start="PNG_DEFN_MAGIC-"      # Arbitrary start
-   end="-PNG_DEFN_END"          # Arbitrary end
-   ct="PNG_JOIN"                # Join two tokens
-   cx= "/" ct "*"               # Open C comment for output file
-   comment=start cx             # Comment start
-   cend="*/" end                # Comment end
-   def=start "#define PNG_" ct  # Arbitrary define
-   sup=ct "_SUPPORTED 1" end    # end supported option
-   und=comment "#undef PNG_" ct # Unsupported option
-   une=ct "_SUPPORTED" cend     # end unsupported option
-   error=start "ERROR:"         # error message
-
-   # Variables
-   deb=0                        # debug - set on command line
-   everything=""                # do not override defaults
-   logunsupported=0             # write unsupported options too
-
-   # Precreate arrays
-   option[""] = ""    # list of all options: default enabled/disabled
-   done[""] = 1       # marks option as having been output
-   requires[""] = ""  # requires by option
-   iffs[""] = ""      # if by option
-   enabledby[""] = "" # options that enable it by option
-   setting[""] = ""   # requires by setting
-   defaults[""] = ""  # used for a defaulted value
-   doneset[""] = 1    # marks setting as having been output
-   r[""] = ""         # Temporary array
-
-   # For decorating the output file
-   protect = ""
-}
-
-# The output file must be specified before any input:
-out == "/dev/null" {
-   print "out=output.file must be given on the command line"
-   err = 1
-   exit 1
-}
-
-# The very first line indicates whether we are reading pre-processed
-# input or not, this must come *first* because 'PREPROCESSED' needs
-# to be the very first line in the temporary file.
-pre == -1{
-   if ($0 == "PREPROCESSED") {
-      pre = 0
-      next
-   } else {
-      pre = 1
-      print "PREPROCESSED" >out
-      # And fall through to continue processing
-   }
-}
-
-# While pre-processing if version is set to "search" look for a version string
-# in the following file.
-pre && version == "search" && version_file == ""{
-   version_file = FILENAME
-}
-
-pre && version == "search" && version_file != FILENAME{
-   print "version string not found in", version_file
-   err = 1
-   exit 1
-}
-
-pre && version == "search" && $0 ~ /^ \* libpng version/{
-   version = substr($0, 4)
-   print "version =", version >out
-   next
-}
-
-pre && FILENAME == version_file{
-   next
-}
-
-# variable=value
-#   Sets the given variable to the given value (the syntax is fairly
-#   free form, except for deb (you are expected to understand how to
-#   set the debug variable...)
-#
-#   This happens before the check on 'pre' below skips most of the
-#   rest of the actions, so the variable settings happen during
-#   preprocessing but are recorded in the END action too.  This
-#   allows them to be set on the command line too.
-$0 ~ /^[ 	]*version[ 	]*=/{
-   sub(/^[  ]*version[  ]*=[  ]*/, "")
-   version = $0
-   next
-}
-$0 ~ /^[ 	]*everything[ 	=]*off[ 	]*$/{
-   everything = "off"
-   next
-}
-$0 ~ /^[ 	]*everything[ 	=]*on[ 	]*$/{
-   everything = "on"
-   next
-}
-$0 ~ /^[ 	]*logunsupported[ 	=]*0[ 	]*$/{
-   logunsupported = 0
-   next
-}
-$0 ~ /^[ 	]*logunsupported[ 	=]*1[ 	]*$/{
-   logunsupported = 1
-   next
-}
-$1 == "deb" && $2 == "=" && NF == 3{
-   deb = $3
-   next
-}
-
-# Preprocessing - this just copies the input file with lines
-# that need preprocessing (just chunk at present) expanded
-# The bare "pre" instead of "pre != 0" crashes under Sunos awk
-pre && $1 != "chunk"{
-   print >out
-   next
-}
-
-# The first characters of the line determine how it is processed,
-# leading spaces are ignored.  In general tokens that are not
-# keywords are the names of options.  An option 'name' is
-# controlled by the definition of the corresponding macros:
-#
-#   PNG_name_SUPPORTED    The option is turned on
-#   PNG_NO_name
-#   PNG_NO_name_SUPPORTED If the first macro is not defined
-#                         either of these will turn the option off
-#
-# If none of these macros are defined the option is turned on, unless
-# the keyword 'off' is given in a line relating to the option.  The
-# keyword 'on' can also be given, but it will be ignored (since it is
-# the default.)
-#
-# In the syntax below a 'name' is indicated by "NAME", other macro
-# values are indicated by "MACRO", as with "NAME" the leading "PNG_"
-# is omitted, but in this case the "NO_" prefix and the "_SUPPORTED"
-# suffix are never used.
-#
-# Each line is introduced by a keyword - the first non-space characters
-# on the line.  A line starting with a '#' is a comment - it is totally
-# ignored.  Keywords are as follows, a NAME, is simply a macro name
-# without the leading PNG_, PNG_NO_ or the trailing _SUPPORTED.
-
-$1 ~ /^#/ || $0 ~ /^[ 	]*$/{
-   next
-}
-
-# com <comment>
-#   The whole line is placed in the output file as a comment with
-#   the preceding 'com' removed
-$1 == "com"{
-   if (NF > 1) {
-      # sub(/^[ 	]*com[ 	]*/, "")
-      $1 = ""
-      print comment, $0, cend >out
-   } else
-      print start end >out
-   next
-}
-
-# version
-#   Inserts a version comment
-$1 == "version" && NF == 1{
-   if (version == "") {
-      print "ERROR: no version string set"
-      err = 1 # prevent END{} running
-      exit 1
-   }
-
-   print comment, version, cend >out
-   next
-}
-
-# file output input protect
-#   Informational: the official name of the input file (without
-#   make generated local directories), the official name of the
-#   output file and, if required, a name to use in a protection
-#   macro for the contents.
-$1 == "file" && NF >= 2{
-   print comment, $2, cend >out
-   print comment, "Machine generated file: DO NOT EDIT", cend >out
-   if (NF >= 3)
-      print comment, "Derived from:", $3, cend >out
-   protect = $4
-   if (protect != "") {
-      print start "#ifndef", protect end >out
-      print start "#define", protect end >out
-   }
-   next
-}
-
-# option NAME ( (requires|enables|if) NAME* | on | off | disabled )*
-#   Declares an option 'NAME' and describes its default setting (disabled)
-#   and its relationship to other options.  The option is disabled
-#   unless *all* the options listed after 'requires' are set and at
-#   least one of the options listed after 'if' is set.  If the
-#   option is set then it turns on all the options listed after 'enables'.
-#
-#   Note that "enables" takes priority over the required/if/disabled/off
-#   setting of the target option.
-#
-#   The definition file may list an option as 'disabled': off by default,
-#   otherwise the option is enabled: on by default.  A later (and it must
-#   be later) entry may turn an option on or off explicitly.
-
-$1 == "option" && NF >= 2{
-   onoff = option[$2]  # records current (and the default is "", enabled)
-   key = ""
-   for (i=3; i<=NF; ++i) {
-      if ($(i) == "on" || $(i) == "off" || $(i) == "disabled") {
-         key = ""
-         if (onoff != $(i)) {
-            # on or off can zap disabled or enabled:
-            if (onoff == "" || (onoff == "disabled" || onoff == "enabled") && ($(i) == "on" || $(i) == "off")) {
-               # It's easy to mis-spell the option when turning it
-               # on or off, so warn about it here:
-               if (onoff == "" && ($(i) == "on" || $(i) == "off")) {
-                  print $2 ": ERROR: turning unrecognized option", $(i)
-                  # For the moment error out - it is safer
-                  err = 1 # prevent END{} running
-                  exit 1
-               }
-               onoff = $(i)
-            } else {
-               # Print a message, otherwise the error
-               # below is incomprehensible
-               print $2 ": currently", onoff ": attempt to turn", $(i)
-               break
-            }
-         }
-      } else if ($(i) == "requires" || $(i) == "if" || $(i) == "enables") {
-         key = $(i)
-      } else if (key == "requires") {
-         requires[$2] = requires[$2] " " $(i)
-      } else if (key == "if") {
-         iffs[$2] = iffs[$2] " " $(i)
-      } else if (key == "enables") {
-         enabledby[$(i)] = enabledby[$(i)] " " $2
-      } else
-         break # bad line format
-   }
-
-   if (i > NF) {
-      # Set the option, defaulting to 'enabled'
-      if (onoff == "") onoff = "enabled"
-      option[$2] = onoff
-      next
-   }
-   # Else fall through to the error handler
-}
-
-# chunk NAME [requires OPT] [on|off|disabled]
-#   Expands to the 'option' settings appropriate to the reading and
-#   writing of an ancilliary PNG chunk 'NAME':
-#
-#   option READ_NAME requires READ_ANCILLARY_CHUNKS [READ_OPT]
-#   option READ_NAME enables NAME
-#   [option READ_NAME off]
-#   option WRITE_NAME requires WRITE_ANCILLARY_CHUNKS [WRITE_OPT]
-#   option WRITE_NAME enables NAME
-#   [option WRITE_NAME off]
-
-pre != 0 && $1 == "chunk" && NF >= 2{
-   # 'chunk' is handled on the first pass by writing appropriate
-   # 'option' lines into the intermediate file.
-   onoff = ""
-   reqread = ""
-   reqwrite = ""
-   i = 3 # indicates format error
-   if (NF > 2) {
-      # read the keywords/additional OPTS
-      req = 0
-      for (i=3; i<=NF; ++i) {
-         if ($(i) == "on" || $(i) == "off" || $(i) == "disabled") {
-            if (onoff != $(i)) {
-               if (onoff == "")
-                  onoff = $(i)
-               else
-                  break # on/off conflict
-            }
-         } else if ($(i) == "requires")
-            req = 1
-         else if (req != 1)
-            break # bad line: handled below
-         else {
-            reqread = reqread " READ_" $(i)
-            reqwrite = reqwrite " WRITE_" $(i)
-         }
-      }
-   }
-
-   if (i > NF) {
-      # Output new 'option' lines to the intermediate file (out)
-      print "option READ_" $2, "requires READ_ANCILLARY_CHUNKS" reqread, "enables", $2, onoff >out
-      print "option WRITE_" $2, "requires WRITE_ANCILLARY_CHUNKS" reqwrite, "enables", $2, onoff >out
-      next
-   }
-   # Else hit the error handler below - bad line format!
-}
-
-# setting MACRO ( requires MACRO* )* [ default VALUE ]
-#   Behaves in a similar way to 'option' without looking for NO_ or
-#   _SUPPORTED; the macro is enabled if it is defined so long as all
-#   the 'requires' macros are also defined.  The definitions may be
-#   empty, an error will be issued if the 'requires' macros are
-#   *not* defined.  If given the 'default' value is used if the
-#   macro is not defined.  The default value will be re-tokenised.
-#   (BTW: this is somewhat restrictive, it mainly exists for the
-#   support of non-standard configurations and numeric parameters,
-#   see the uses in scripts/options.dat
-
-$1 == "setting" && (NF == 2 || NF >= 3 && ($3 == "requires" || $3 == "default")){
-   reqs = ""
-   deflt = ""
-   isdef = 0
-   key = ""
-   for (i=3; i<=NF; ++i)
-      if ($(i) == "requires" || $(i) == "default") {
-         key = $(i)
-         if (key == "default") isdef = 1
-      } else if (key == "requires")
-         reqs = reqs " " $(i)
-      else if (key == "default")
-         deflt = deflt " " $(i)
-      else
-         break # Format error, handled below
-
-   setting[$2] = reqs
-   # NOTE: this overwrites a previous value silently
-   if (isdef && deflt == "")
-      deflt = " " # as a flag to force output
-   defaults[$2] = deflt
-   next
-}
-
-# The order of the dependency lines (option, chunk, setting) is irrelevant
-# - the 'enables', 'requires' and 'if' settings will be used to determine
-# the correct order in the output and the final values in pnglibconf.h are
-# not order dependent.  'requires' and 'if' entries take precedence over
-# 'enables' from other options; if an option requires another option it
-# won't be set regardless of any options that enable it unless the other
-# option is also enabled.
-#
-# Similarly 'enables' trumps a NO_ definition in CFLAGS or pngusr.h
-#
-# For simplicity cycles in the definitions are regarded as errors,
-# even if they are not ambiguous.
-# A given NAME can be specified in as many 'option' lines as required, the
-# definitions are additive.
-
-# For backwards compatibility equivalent macros may be listed thus:
-#
-# = [NO_]NAME MACRO
-#   Makes -DMACRO equivalent to -DPNG_NO_NAME or -DPNG_NAME_SUPPORTED
-#   as appropriate.
-#
-# The definition is injected into the C compiler input when encountered
-# in the second pass (so all these definitions appear *after* the @
-# lines!)
-#
-# 'NAME' is as above, but 'MACRO' is the full text of the equivalent
-# old, deprecated, macro.
-
-$1 == "=" && NF == 3{
-   print "#ifdef PNG_" $3 >out
-   if ($2 ~ /^NO_/)
-      print "#   define PNG_" $2 >out
-   else
-      print "#   define PNG_" $2 "_SUPPORTED" >out
-   print "#endif" >out
-   next
-}
-
-# Lines may be injected into the C compiler input by preceding them
-# with an "@" character.  The line is copied with just the leading
-# @ removed.
-
-$1 ~ /^@/{
-   # sub(/^[ 	]*@/, "")
-   $1 = substr($1, 2)
-   print >out
-   next
-}
-
-# Check for unreognized lines, because of the preprocessing chunk
-# format errors will be detected on the first pass independent of
-# any other format errors.
-{
-   print "options.awk: bad line (" NR "):", $0
-   err = 1 # prevent END{} running
-   exit 1
-}
-
-# For checking purposes names that start with "ok_" or "fail_" are
-# not output to pnglibconf.h and must be either enabled or disabled
-# respectively for the build to succeed.  This allows interdependencies
-# between options of the form "at least one of" or "at most one of"
-# to be checked.  For example:
-#
-# option FLOATING_POINT enables ok_math
-# option FIXED_POINT enables ok_math
-#   This ensures that at least one of FLOATING_POINT and FIXED_POINT
-#   must be set for the build to succeed.
-#
-# option fail_math requires FLOATING_POINT FIXED_POINT
-#   This means the build will fail if *both* FLOATING_POINT and
-#   FIXED_POINT are set (this is an example; in fact both are allowed.)
-#
-# If all these options were given the build would require exactly one
-# of the names to be enabled.
-
-END{
-   # END{} gets run on an exit (a traditional awk feature)
-   if (err) exit 1
-
-   if (pre) {
-      # Record the final value of the variables
-      print "deb =", deb >out
-      if (everything != "") {
-         print "everything =", everything >out
-      }
-      print "logunsupported =", logunsupported >out
-      exit 0
-   }
-
-   # Do the 'setting' values first, the algorithm the standard
-   # tree walk (O(1)) done in an O(2) while/for loop; interations
-   # settings x depth, outputing the deepest required macros
-   # first.
-   print "" >out
-   print "/* SETTINGS */" >out
-   print comment, "settings", cend >out
-   finished = 0
-   while (!finished) {
-      finished = 1
-      movement = 0 # done nothing
-      for (i in setting) if (!doneset[i]) {
-         nreqs = split(setting[i], r)
-         if (nreqs > 0) {
-            for (j=1; j<=nreqs; ++j) if (!doneset[r[j]]) {
-               break
-            }
-            if (j<=nreqs) {
-               finished = 0
-               continue # try a different setting
-            }
-         }
-
-         # All the requirements have been processed, output
-         # this setting.
-         if (deb) print "setting", i
-         print "" >out
-         print "/* setting: ", i >out
-         print " *   requires:" setting[i] >out
-         print " *   default: ", defaults[i], "*/" >out
-         if (defaults[i] == "") { # no default, only check if defined
-            print "#ifdef PNG_" i >out
-         }
-         for (j=1; j<=nreqs; ++j) {
-            print "# ifndef PNG_" r[j] >out
-            print error, i, "requires", r[j] end >out
-            print "# endif" >out
-         }
-         if (defaults[i] != "") { # default handling
-            print "#ifdef PNG_" i >out
-         }
-         print def i, "PNG_" i end >out
-         if (defaults[i] != "") {
-            print "#else /*default*/" >out
-            # And add the default definition for the benefit
-            # of later settings an options test:
-            print "# define PNG_" i defaults[i] >out
-            print def i defaults[i] end >out
-         }
-         print "#endif" >out
-
-         doneset[i] = 1
-         ++movement
-      }
-
-      if (!finished && !movement) {
-         print "setting: loop or missing setting in 'requires', cannot process:"
-         for (i in setting) if (!doneset[i]) {
-            print "  setting", i, "requires" setting[i]
-         }
-         exit 1
-      }
-   }
-   print comment, "end of settings", cend >out
-
-   # Now do the options - somewhat more complex.  The dependency
-   # tree is thus:
-   #
-   #   name     >     name
-   #   name requires  name
-   #   name if        name
-   #   name enabledby name
-   #
-   # First build a list 'tree' by option of all the things on which
-   # it depends.
-   print "" >out
-   print "/* OPTIONS */" >out
-   print comment, "options", cend >out
-   for (opt in enabledby) tree[opt] = 1  # may not be explicit options
-   for (opt in option) if (opt != "") {
-      o = option[opt]
-      # option should always be one of the following values
-      if (o != "on" && o != "off" && o != "disabled" && o != "enabled") {
-         print "internal option error (" o ")"
-         exit 1
-      }
-      tree[opt] = ""   # so unlisted options marked
-   }
-   for (opt in tree) if (opt != "") {
-      if (tree[opt] == 1) {
-         tree[opt] = ""
-         if (option[opt] != "") {
-            print "internal error (1)"
-            exit 1
-         }
-         # Macros only listed in 'enables' remain off unless
-         # one of the enabling macros is on.
-         option[opt] = "disabled"
-      }
-
-      split("", list) # clear 'list'
-      # Now add every requires, iffs or enabledby entry to 'list'
-      # so that we can add a unique list of requirements to tree[i]
-      split(requires[opt] iffs[opt] enabledby[opt], r)
-      for (i in r) list[r[i]] = 1
-      for (i in list) tree[opt] = tree[opt] " " i
-   }
-
-   # print the tree for extreme debugging
-   if (deb > 2) for (i in tree) if (i != "") print i, "depends-on" tree[i]
-
-   # Ok, now check all options marked explicitly 'on' or 'off':
-   #
-   # If an option[opt] is 'on' then turn on all requires[opt]
-   # If an option[opt] is 'off' then turn off all enabledby[opt]
-   #
-   # Error out if we have to turn 'on' an 'off' option or vice versa.
-   npending = 0
-   for (opt in option) if (opt != "") {
-      if (option[opt] == "on" || option[opt] == "off") {
-         pending[++npending] = opt
-      }
-   }
-
-   err = 0 # set on error
-   while (npending > 0) {
-      opt = pending[npending--]
-      if (option[opt] == "on") {
-         nreqs = split(requires[opt], r)
-         for (j=1; j<=nreqs; ++j) {
-            if (option[r[j]] == "off") {
-               print "option", opt, "turned on, but requirement", r[j], "is turned off"
-               err = 1
-            } else if (option[r[j]] != "on") {
-               option[r[j]] = "on"
-               pending[++npending] = r[j]
-            }
-         }
-      } else {
-         if (option[opt] != "off") {
-            print "internal error (2)"
-            exit 1
-         }
-         nreqs = split(enabledby[opt], r)
-         for (j=1; j<=nreqs; ++j) {
-            if (option[r[j]] == "on") {
-               print "option", opt, "turned off, but enabled by", r[j], "which is turned on"
-               err = 1
-            } else if (option[r[j]] != "off") {
-               option[r[j]] = "off"
-               pending[++npending] = r[j]
-            }
-         }
-      }
-   }
-   if (err) exit 1
-
-   # option[i] is now the complete list of all the tokens we may
-   # need to output, go through it as above, depth first.
-   finished = 0
-   while (!finished) {
-      finished = 1
-      movement = 0 # done nothing
-      for (i in option) if (!done[i]) {
-         nreqs = split(tree[i], r)
-         if (nreqs > 0) {
-            for (j=1; j<=nreqs; ++j) if (!done[r[j]]) {
-               break
-            }
-            if (j<=nreqs) {
-               finished = 0
-               continue  # next option
-            }
-         }
-
-         # All the requirements have been processed, output
-         # this option.  An option is _SUPPORTED if:
-         #
-         # all 'requires' are _SUPPORTED AND
-         # at least one of the 'if' options are _SUPPORTED AND
-         # EITHER:
-         #   The name is _SUPPORTED (on the command line)
-         # OR:
-         #   an 'enabledby' is _SUPPORTED
-         # OR:
-         #   NO_name is not defined AND
-         #   the option is not disabled; an option is disabled if:
-         #    option == off
-         #    option == disabled && everything != on
-         #    option == "" && everything == off
-         if (deb) print "option", i
-         print "" >out
-         print "/* option:", i, option[i] >out
-         print " *   requires:  " requires[i] >out
-         print " *   if:      " iffs[i] >out
-         print " *   enabled-by:" enabledby[i], "*/" >out
-         print "#undef PNG_on" >out
-         print "#define PNG_on 1" >out
-
-         # requires
-         nreqs = split(requires[i], r)
-         for (j=1; j<=nreqs; ++j) {
-            print "#ifndef PNG_" r[j] "_SUPPORTED" >out
-            print "#   undef PNG_on /*!" r[j] "*/" >out
-            # this error appears in the final output if something
-            # was switched 'on' but the processing above to force
-            # the requires did not work
-            if (option[i] == "on") {
-               print error, i, "requires", r[j] end >out
-            }
-            print "#endif" >out
-         }
-
-         # if
-         nreqs = split(iffs[i], r)
-         print "#undef PNG_no_if" >out
-         if (nreqs > 0) {
-            print "/* if" iffs[i], "*/" >out
-            print "#define PNG_no_if 1" >out
-            for (j=1; j<=nreqs; ++j) {
-               print "#ifdef PNG_" r[j] "_SUPPORTED" >out
-               print "#   undef PNG_no_if /*" r[j] "*/" >out
-               print "#endif" >out
-            }
-            print "#ifdef PNG_no_if /*missing if*/" >out
-            print "#   undef PNG_on" >out
-            # There is no checking above for this, because we
-            # don't know which 'if' to choose, so whine about
-            # it here:
-            if (option[i] == "on") {
-               print error, i, "needs one of:", iffs[i] end >out
-            }
-            print "#endif" >out
-         }
-
-         print "#ifdef PNG_on /*requires, if*/" >out
-         # enables
-         print "#   undef PNG_not_enabled" >out
-         print "#   define PNG_not_enabled 1" >out
-         print "   /* enabled by" enabledby[i], "*/" >out
-         nreqs = split(enabledby[i], r)
-         for (j=1; j<=nreqs; ++j) {
-            print "#ifdef PNG_" r[j] "_SUPPORTED" >out
-            print "#   undef PNG_not_enabled /*" r[j] "*/" >out
-            # Oops, probably not intended (should be factored
-            # out by the checks above).
-            if (option[i] == "off") {
-               print error, i, "enabled by:", r[j] end >out
-            }
-            print "#endif" >out
-         }
-
-         print "#   ifndef PNG_" i "_SUPPORTED /*!command line*/" >out
-         print "#    ifdef PNG_not_enabled /*!enabled*/" >out
-         if (option[i] == "off" || option[i] == "disabled" && everything != "on" || option[i] == "enabled" && everything == "off") {
-            print "#      undef PNG_on /*default off*/" >out
-         } else {
-            print "#      ifdef PNG_NO_" i >out
-            print "#       undef PNG_on /*turned off*/" >out
-            print "#      endif" >out
-            print "#      ifdef PNG_NO_" i "_SUPPORTED" >out
-            print "#       undef PNG_on /*turned off*/" >out
-            print "#      endif" >out
-         }
-         print "#    endif /*!enabled*/" >out
-         print "#    ifdef PNG_on" >out
-         # The _SUPPORTED macro must be defined so that dependent
-         # options output later work.
-         print "#      define PNG_" i "_SUPPORTED" >out
-         print "#    endif" >out
-         print "#   endif /*!command line*/" >out
-         # If PNG_on is still set the option should be defined in
-         # pnglibconf.h
-         print "#   ifdef PNG_on" >out
-         if (i ~ /^fail_/) {
-            print error, i, "is on: enabled by:" iffs[i] enabledby[i] ", requires" requires[i] end >out
-         } else if (i !~ /^ok_/) {
-            print def i sup >out
-         }
-         print "#   endif /* definition */" >out
-         print "#endif /*requires, if*/" >out
-         if (logunsupported || i ~ /^ok_/) {
-            print "#ifndef  PNG_on" >out
-            if (logunsupported) {
-               print und i une >out
-            }
-            if (i ~ /^ok_/) {
-               print error, i, "not enabled: requires:" requires[i] ", enabled by:" iffs[i] enabledby[i] end >out
-            }
-            print "#endif" >out
-         }
-
-         done[i] = 1
-         ++movement
-      }
-
-      if (!finished && !movement) {
-         print "option: loop or missing option in dependency tree, cannot process:"
-         for (i in option) if (!done[i]) {
-            print "  option", i, "depends on" tree[i], "needs:"
-            nreqs = split(tree[i], r)
-            if (nreqs > 0) for (j=1; j<=nreqs; ++j) if (!done[r[j]]) {
-               print "   " r[j]
-            }
-         }
-         exit 1
-      }
-   }
-   print comment, "end of options", cend >out
-
-   # Regular end - everything looks ok
-   if (protect != "") {
-      print start "#endif", cx, protect, "*/" end >out
-   }
-}
diff --git a/extern/libpng/include/scripts/pnglibconf.dfa b/extern/libpng/include/scripts/pnglibconf.dfa
deleted file mode 100644
index f06eb66857..0000000000
--- a/extern/libpng/include/scripts/pnglibconf.dfa
+++ /dev/null
@@ -1,590 +0,0 @@
-# scripts/pnglibconf.dfa - library build configuration control
-#
-@/*- pnglibconf.dfn intermediate file
-@ *  generated from scripts/pnglibconf.dfa
-@ */
-#
-com pnglibconf.h - library build configuration
-com
-version
-com
-com Copyright (c) 1998-2011 Glenn Randers-Pehrson
-com
-com This code is released under the libpng license.
-com For conditions of distribution and use, see the disclaimer
-com and license in png.h
-com
-
-file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H
-
-# This file is preprocessed by scripts/options.awk and the
-# C compiler to generate 'pnglibconf.h' - a list of all the
-# configuration options.  The file lists the various options
-# that can *only* be specified during the libpng build;
-# pnglibconf.h freezes the definitons selected for the specific
-# build.
-#
-# The syntax is detailed in scripts/options.awk, this is a summary
-# only:
-#
-# setting <name> [default]
-#    #define PNG_<name> <value>  /* value comes from current setting */
-# option <name> [requires ...] [if ...] [enables ...] [disabled]
-#    #define PNG_<name>_SUPPORTED if the requirements are met and
-#    enable the other options listed
-# chunk <name> [requires ...] [disabled]
-#    Enable chunk processing for the given ancillary chunk
-#
-# Note that the 'on' and 'off' keywords, while valid on both option
-# and chunk, should not be used in this file because they force the
-# relevant options on or off.
-
-#----------------------------------------------------------------------
-
-# The following setting, option and chunk values can all be changed
-# while building libpng:
-#
-# setting: change 'setting' lines to fine tune library performance,
-#   changes to the settings don't affect the libpng API functionally
-#
-# option: change 'option' lines to remove or add capabilities from
-#   or to the library; options change the library API
-#
-# chunk: change 'chunk' lines to remove capabilities to process
-#   optional ('ancillary') chunks.  This does not prevent PNG
-#   decoding but does change the libpng API because some chunks
-#   will be ignored.
-#
-# There are three ways of disabling features, in no particular order:
-#
-# 1) Create 'pngusr.h', enter the required private build information
-# detailed below and #define PNG_NO_<option> for each option you
-# don't want in that file in that file.  You can also turn on options
-# using PNG_<option>_SUPPORTED.  When you have finished rerun
-# configure and rebuild pnglibconf.h file with -DPNG_USER_CONFIG:
-#
-#  make clean
-#  CPPFLAGS='-DPNG_USER_CONFIG' ./configure
-#  make pnglibconf.h
-#
-# pngusr.h is only used during the creation of pnglibconf.h, but it
-# is safer to ensure that -DPNG_USER_CONFIG is specified throughout
-# the build by changing the CPPFLAGS passed to the initial ./configure
-#
-# 2) Add definitions of the settings you want to change to
-# CPPFLAGS; for example:
-#
-#   -DPNG_DEFAULT_READ_MACROS=0
-#
-# (This would change the default to *not* use read macros.)  Be
-# very careful to change only settings that don't alter the API
-# because this approach bypasses the private build checking.  You
-# can also change settings from pngpriv.h (read pngpriv.h) safely
-# without API changes.  Do that in the same way.
-#
-# 3) Write a new '.dfa' file (say 'pngusr.dfa') and in this file
-# provide override values for setting entries and turn option or
-# chunk values explicitly 'on' or 'off':
-#
-#    setting FOO default VALUE
-#    option BAR [on|off]
-#
-# Then add this file to the options.awk command line (the *first*
-# one) after this file.  The make macro DFA_XTRA is provided to make
-# this easier (set it like CPPFLAGS prior to running ./configure).
-# Look at the builds below contrib/pngminim for some extreme examples
-# of how this can be used.
-#
-# Don't edit this file unless you are contributing a patch to
-# libpng and need new or modified options/settings.
-#----------------------------------------------------------------------
-
-# The following causes commented out #undef lines to be written to
-# pnglibconf.h; this can be stopped by logunsupported=0 in a later
-# file or on the command line (after pnglibconf.dfa)
-
-logunsupported = 1
-
-# PNG_USER_CONFIG has to be defined on the compiler command line
-# to cause pngusr.h to be read while constructing pnglibconf.h
-#
-# If you create a private DLL you need to define the following
-# macros in the file 'pngusr.h' and set -DPNG_USER_CONFIG for
-# compilation (i.e. in CFLAGS.)
-# #define PNG_USER_PRIVATEBUILD \
-#     <Describes by whom and why this version of the DLL was built>
-#  e.g. #define PNG_USER_PRIVATEBUILD "Build by MyCompany for xyz reasons."
-# #define PNG_USER_DLLFNAME_POSTFIX <two-letter postfix that serve to
-#        distinguish your DLL from those of the official release. These
-#        correspond to the trailing letters that come after the version
-#        number and must match your private DLL name>
-#  e.g. // private DLL "libpng13gx.dll"
-#       #define PNG_USER_DLLFNAME_POSTFIX "gx"
-#
-# The following macros are also at your disposal if you want to complete the
-# DLL VERSIONINFO structure.
-# - PNG_USER_VERSIONINFO_COMMENTS
-# - PNG_USER_VERSIONINFO_COMPANYNAME
-# - PNG_USER_VERSIONINFO_LEGALTRADEMARKS
-
-@#ifdef PNG_USER_CONFIG
-@#  include "pngusr.h"
-@#endif
-
-# This is a special fixup for the Watcom C compiler on Windows, which has
-# multiple procedure call standards.  Unless PNG_API_RULE is set explicitly
-# (i.e. if it is not defined at this point) it will be forced to '2' here when
-# using Watcom.  This indicates to the other header files that Watcom behaviour
-# is required where appropriate.
-
-@#ifdef __WATCOMC__
-@#  ifndef PNG_API_RULE
-@#     define PNG_API_RULE 2 /* Use Watcom calling conventions */
-@#  endif
-@#endif
-
-# Note that PNG_USR_CONFIG only has an effect when building
-# pnglibconf.h
-
-setting USER_CONFIG
-setting USER_PRIVATEBUILD
-setting USER_DLLFNAME_POSTFIX
-setting USER_VERSIONINFO_COMMENTS
-setting USER_VERSIONINFO_COMPANYNAME
-setting USER_VERSIONINFO_LEGALTRADEMARKS
-
-# Record the 'API rule' used to select calling conventions on
-# those systems that support such things (see all the comments in
-# pngconf.h)
-# Changing this setting has a fundamental affect on the PNG ABI,
-# do not release shared libraries with this changed.
-
-setting API_RULE default 0
-
-# Default to using the read macros
-
-setting DEFAULT_READ_MACROS default 1
-
-# The alternative is to call functions to read PNG values, if
-# the functions are turned *off* the read macros must always
-# be enabled, so turning this off will actually force the
-# USE_READ_MACROS option on (see pngconf.h)
-
-option READ_INT_FUNCTIONS requires READ
-
-# The same for write, but these can only be switched off if
-# no writing is required at all - hence the use of an 'enables'
-# not a 'requires' below:
-
-option WRITE_INT_FUNCTIONS disabled
-option WRITE enables WRITE_INT_FUNCTIONS
-
-# Generic options - affect both read and write.
-
-option WARNINGS
-option BENIGN_ERRORS
-option MNG_FEATURES
-
-# Arithmetic options, the first is the big switch that chooses between internal
-# floating and fixed point arithmetic implementations - it does not affect any
-# APIs.  The second two (the _POINT settings) switch off individual APIs.
-
-option FLOATING_ARITHMETIC
-option FLOATING_POINT enables ok_math
-option FIXED_POINT enables ok_math
-
-# Added at libpng version 1.4.0
-
-option ERROR_TEXT
-
-# The following is always on (defined empty)
-
-setting CALLOC_SUPPORTED default
-
-# This protects us against compilers that run on a windowing system
-# and thus don't have or would rather us not use the stdio types:
-# stdin, stdout, and stderr.  The only one currently used is stderr
-# in png_error() and png_warning().  #defining PNG_NO_CONSOLE_IO will
-# prevent these from being compiled and used. #defining PNG_NO_STDIO
-# will also prevent these, plus will prevent the entire set of stdio
-# macros and functions (FILE *, printf, etc.) from being compiled and used,
-# unless (PNG_DEBUG > 0) has been #defined.
-
-option STDIO
-option CONSOLE_IO requires STDIO
-
-# Note: prior to 1.5.0 this option could not be disabled if STDIO
-# was enabled.  Prior to 1.5.3 this option required STDIO
-
-option TIME_RFC1123
-
-# PNG_SETJMP_NOT_SUPPORTED is an old equivalent for NO_SETJMP
-
-option SETJMP
-= NO_SETJMP SETJMP_NOT_SUPPORTED
-
-# For the moment this is disabled (no code support):
-
-option ERROR_NUMBERS disabled
-
-# If this is disabled it is not possible for apps to get the
-# values from the 'info' structure, this effectively removes
-# quite a lot of the READ API.
-
-option EASY_ACCESS
-
-# Added at libpng-1.2.0
-
-option USER_MEM
-
-# Added at libpng-1.4.0
-
-option IO_STATE
-
-# This is only for PowerPC big-endian and 680x0 systems
-# some testing, not enabled by default.
-# NO LONGER USED
-
-#option READ_BIG_ENDIAN disabled
-
-# Allow users to control limits on what the READ code will
-# read:
-
-# Added at libpng-1.2.43; adds limit fields to png_struct,
-# allows some usages of these fields
-
-option USER_LIMITS
-
-# Added at libpng-1.2.6; adds setting APIs, allows additional
-# usage of this field (UTSL)
-
-option SET_USER_LIMITS requires USER_LIMITS
-
-# Feature added at libpng-1.4.0, this flag added at 1.4.1
-option SET_USER_LIMITS enables SET_CHUNK_CACHE_LIMIT
-# Feature added at libpng-1.4.1, this flag added at 1.4.1
-
-option SET_USER_LIMITS enables SET_CHUNK_MALLOC_LIMIT
-
-# Libpng limits.
-#
-# If these settings are *not* set libpng will not limit the size of
-# images or the size of data in ancilliary chunks.  This does lead to
-# security issues if PNG files come from untrusted sources.
-setting USER_WIDTH_MAX
-setting USER_HEIGHT_MAX
-setting USER_CHUNK_CACHE_MAX
-setting USER_CHUNK_MALLOC_MAX
-
-# To default all these settings to values that are large but probably
-# safe turn the SAFE_LIMITS option on; this will cause the value in
-# pngpriv.h to be used.  Individual values can also be set, simply set
-# them in pngusr.dfa with '@#define PNG_setting value' lines.
-option SAFE_LIMITS enables USER_LIMITS disabled
-= SAFE_LIMITS SAFE_LIMITS
-
-# All of the following options relate to code capabilities for
-# processing image data before creating a PNG or after reading one.
-# You can remove these capabilities safely and still be PNG
-# conformant, however the library that results is still non-standard.
-# See the comments above about how to change options and settings.
-
-# READ options
-
-option READ enables READ_INTERLACING
-
-# Disabling READ_16BIT does not disable reading 16-bit PNG files, but it
-# forces them to be chopped down to 8-bit, and disables any 16-bit
-# processing after that has happened.  You need to be sure to enable
-# READ_SCALE_16_TO_8 or READ_STRIP_16_TO_8 when you disable READ_16BIT for
-# this to work properly.  You should disable the other option if you need to
-# ensure a particular conversion (otherwise the app can chose.)
-
-option READ_16BIT requires READ enables 16BIT
-
-option READ_QUANTIZE requires READ
-
-option READ_TRANSFORMS requires READ
-= NO_READ_TRANSFORMS READ_TRANSFORMS_NOT_SUPPORTED
-
-option READ_EXPAND requires READ_TRANSFORMS
-option READ_EXPAND_16 requires READ_TRANSFORMS READ_16BIT enables READ_EXPAND
-option READ_SHIFT requires READ_TRANSFORMS
-option READ_PACK requires READ_TRANSFORMS
-option READ_BGR requires READ_TRANSFORMS
-option READ_SWAP requires READ_TRANSFORMS READ_16BIT
-option READ_PACKSWAP requires READ_TRANSFORMS
-option READ_INVERT requires READ_TRANSFORMS
-option READ_BACKGROUND requires READ_TRANSFORMS enables READ_STRIP_ALPHA
-option READ_STRIP_16_TO_8 requires READ_TRANSFORMS
-option READ_SCALE_16_TO_8 requires READ_TRANSFORMS
-option READ_FILLER requires READ_TRANSFORMS
-option READ_GAMMA requires READ_TRANSFORMS enables READ_gAMA
-option READ_GRAY_TO_RGB requires READ_TRANSFORMS
-
-option READ_ALPHA_MODE requires READ_TRANSFORMS enables READ_GAMMA
-option READ_SWAP_ALPHA requires READ_TRANSFORMS
-option READ_INVERT_ALPHA requires READ_TRANSFORMS
-option READ_STRIP_ALPHA requires READ_TRANSFORMS
-option READ_USER_TRANSFORM requires READ_TRANSFORMS
-option READ_RGB_TO_GRAY requires READ_TRANSFORMS
-
-option PROGRESSIVE_READ requires READ
-option SEQUENTIAL_READ requires READ
-
-# You can define PNG_NO_PROGRESSIVE_READ if you don't do progressive reading.
-# This is not talking about interlacing capability!  You'll still have
-# interlacing unless you turn off the following which is required
-# for PNG-compliant decoders.  (In other words, do not do this - in
-# fact it can't be disabled from the command line!)
-#option READ_INTERLACING requires READ
-
-option READ_COMPOSITE_NODIV requires READ
-= NO_READ_COMPOSITE_NODIV NO_READ_COMPOSITED_NODIV
-
-# Inch conversions
-
-option INCH_CONVERSIONS
-= INCH_CONVERSIONS INCH_CONVERSIONS
-
-# API to build a grayscale palette
-
-option BUILD_GRAYSCALE_PALETTE
-
-# IN DEVELOPMENT
-# These are currently experimental features; define them if you want
-
-# NOTHING HERE
-
-# WRITE options
-
-option WRITE
-
-# Disabling WRITE_16BIT prevents 16-bit PNG files from being
-# generated.
-option WRITE_16BIT requires WRITE enables 16BIT
-
-option WRITE_TRANSFORMS requires WRITE
-= NO_WRITE_TRANSFORMS WRITE_TRANSFORMS_NOT_SUPPORTED
-
-option WRITE_SHIFT requires WRITE_TRANSFORMS
-option WRITE_PACK requires WRITE_TRANSFORMS
-option WRITE_BGR requires WRITE_TRANSFORMS
-option WRITE_SWAP requires WRITE_TRANSFORMS WRITE_16BIT
-option WRITE_PACKSWAP requires WRITE_TRANSFORMS
-option WRITE_INVERT requires WRITE_TRANSFORMS
-option WRITE_FILLER requires WRITE_TRANSFORMS
-option WRITE_SWAP_ALPHA requires WRITE_TRANSFORMS
-option WRITE_INVERT_ALPHA requires WRITE_TRANSFORMS
-option WRITE_USER_TRANSFORM requires WRITE_TRANSFORMS
-
-# This is not required for PNG-compliant encoders, but can cause
-# trouble if left undefined
-
-option WRITE_INTERLACING requires WRITE
-
-# The following depends, internally, on WEIGHT_SHIFT and COST_SHIFT
-# where are set below.
-
-option WRITE_WEIGHTED_FILTER requires WRITE
-
-option WRITE_FLUSH requires WRITE
-
-# Note: these can be turned off explicitly if not required by the
-# apps implementing the user transforms
-option USER_TRANSFORM_PTR if READ_USER_TRANSFORM WRITE_USER_TRANSFORM
-option USER_TRANSFORM_INFO if READ_USER_TRANSFORM WRITE_USER_TRANSFORM
-
-# This enables API to set compression parameters for compressing
-# non-IDAT chunks (zTXt, iTXt, iCCP, and unknown chunks).  This feature
-# was added at libpng-1.5.3.
-option WRITE_CUSTOMIZE_ZTXT_COMPRESSION requires WRITE
-
-# Any chunks you are not interested in, you can undef here.  The
-# ones that allocate memory may be expecially important (hIST,
-# tEXt, zTXt, tRNS, pCAL).  Others will just save time and make png_info
-# a bit smaller.
-
-# The size of the png_text structure changed in libpng-1.0.6 when
-# iTXt support was added.  iTXt support was turned off by default through
-# libpng-1.2.x, to support old apps that malloc the png_text structure
-# instead of calling png_set_text() and letting libpng malloc it.  It
-# was turned on by default in libpng-1.4.0.
-
-option READ_ANCILLARY_CHUNKS requires READ
-# PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED is deprecated.
-= NO_READ_ANCILLARY_CHUNKS READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
-
-option WRITE_ANCILLARY_CHUNKS requires WRITE
-# PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED is deprecated.
-= NO_WRITE_ANCILLARY_CHUNKS WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
-
-# These options disable *all* the text chunks if turned off
-
-option READ_TEXT requires READ_ANCILLARY_CHUNKS enables TEXT
-option WRITE_TEXT requires WRITE_ANCILLARY_CHUNKS enables TEXT
-
-# Moved to pnglibconf.h at libpng-1.5.0
-# Feature support: in 1.4 this was in pngconf.h, but the following
-# features have no affect on the libpng API.  Add library
-# only features to the end of this list.  Add features that
-# affect the API above.  (Note: the list of chunks follows
-# the library-only settings.)
-#
-# BUILD TIME ONLY OPTIONS
-#   These options do not affect the API but rather alter how the
-#   API is implemented, they get recorded in pnglibconf.h, but
-#   can't be changed by the application.
-
-# Check the correctness of cHRM chunks
-
-option CHECK_cHRM requires cHRM
-
-#
-# Artificially align memory - the code typically aligns to 8 byte
-# boundaries if this is switched on, it's a small waste of space
-# but can help (in theory) on some architectures.  Only affects
-# internal structures.  Added at libpng 1.4.0
-
-option ALIGN_MEMORY
-
-# Buggy compilers (e.g., gcc 2.7.2.2) need PNG_NO_POINTER_INDEXING
-# See png[wr]util.c, normally this should always be *on*
-
-option POINTER_INDEXING
-
-# Other defines for things like memory and the like can go here.
-
-# BUILD TIME SETTINGS
-# Like build time options these do not affect the API, but they
-# may be useful to applications because they record details of
-# how the API will behave particularly with regard to overall
-# accuracy.
-
-# This controls how fine the quantizing gets.  As this allocates
-# a largish chunk of memory (32K), those who are not as concerned
-# with quantizing quality can decrease some or all of these.
-
-setting QUANTIZE_RED_BITS default 5
-setting QUANTIZE_GREEN_BITS default 5
-setting QUANTIZE_BLUE_BITS default 5
-
-# This controls how fine the gamma correction becomes when you
-# are only interested in 8 bits anyway.  Increasing this value
-# results in more memory being used, and more pow() functions
-# being called to fill in the gamma tables.  Don't set this value
-# less then 8, and even that may not work (I haven't tested it).
-
-setting MAX_GAMMA_8 default 11
-
-# This controls how much a difference in gamma we can tolerate before
-# we actually start doing gamma conversion, it's a fixed point value,
-# so the default below is 0.05, meaning libpng ignores corrections in
-# the range 0.95 to 1.05
-
-setting GAMMA_THRESHOLD_FIXED default 5000
-
-# Scaling factor for filter heuristic weighting calculations
-
-setting WEIGHT_SHIFT default 8
-setting COST_SHIFT default 3
-
-# Precision to use when converting a floating point value to a PNG
-# extension format string in an sCAL chunk (only relevant if the
-# floating point API is enabled)
-
-setting sCAL_PRECISION default 5
-
-# This is the size of the compression buffer, and thus the size of
-# an IDAT chunk.  Make this whatever size you feel is best for your
-# machine.  One of these will be allocated per png_struct.  When this
-# is full, it writes the data to the disk, and does some other
-# calculations.  Making this an extremely small size may slow
-# the library down, but you may want to experiment to determine
-# where it becomes significant, if you are concerned with memory
-# usage.  Note that zlib allocates at least 32Kb also.  For readers,
-# this describes the size of the buffer available to read the data in.
-# Unless this gets smaller than the size of a row (compressed),
-# it should not make much difference how big this is.
-
-setting ZBUF_SIZE default 8192
-
-# Ancillary chunks
-chunk bKGD
-chunk cHRM
-chunk gAMA
-chunk hIST
-chunk iCCP
-chunk iTXt
-chunk oFFs
-chunk pCAL
-chunk sCAL
-chunk pHYs
-chunk sBIT
-chunk sPLT
-chunk sRGB
-chunk tEXt requires TEXT
-chunk tIME
-chunk tRNS
-chunk zTXt
-
-# This only affects support of the optional PLTE chunk in RGB and RGBA
-# images.  Notice that READ_ANCILLARY_CHUNKS therefore disables part
-# of the regular chunk reading too.
-
-option READ_OPT_PLTE requires READ_ANCILLARY_CHUNKS
-
-option READ_UNKNOWN_CHUNKS requires READ
-option READ_UNKNOWN_CHUNKS enables UNKNOWN_CHUNKS READ_USER_CHUNKS
-option READ_USER_CHUNKS requires READ enables USER_CHUNKS
-
-option CONVERT_tIME requires WRITE_ANCILLARY_CHUNKS
-# The "tm" structure is not supported on WindowsCE
-
-@#ifdef _WIN32_WCE
-@#   define PNG_NO_CONVERT_tIME
-@#endif
-
-option WRITE_FILTER requires WRITE
-
-option WRITE_UNKNOWN_CHUNKS requires WRITE
-
-option HANDLE_AS_UNKNOWN
-
-option SAVE_INT_32 requires WRITE
-
-# png_save_int_32 is required by the ancillary chunks oFFs and pCAL
-
-# added at libpng-1.5.4
-
-option WRITE_OPTIMIZE_CMF requires WRITE
-
-option READ_COMPRESSED_TEXT disabled
-option READ_iCCP enables READ_COMPRESSED_TEXT
-option READ_iTXt enables READ_COMPRESSED_TEXT
-option READ_zTXt enables READ_COMPRESSED_TEXT
-option READ_COMPRESSED_TEXT enables READ_TEXT
-
-option WRITE_oFFs enables SAVE_INT_32
-option WRITE_pCAL enables SAVE_INT_32
-
-option WRITE_COMPRESSED_TEXT disabled
-option WRITE_iCCP enables WRITE_COMPRESSED_TEXT
-option WRITE_iTXt enables WRITE_COMPRESSED_TEXT
-option WRITE_zTXt enables WRITE_COMPRESSED_TEXT
-option WRITE_COMPRESSED_TEXT enables WRITE_TEXT
-
-# Turn this off to disable png_read_png() and png_write_png() and
-# leave the row_pointers member out of the info structure.
-
-option INFO_IMAGE
-
-# added at libpng-1.5.10
-# Turn this off to disable warning about invalid palette index and
-# leave the num_palette_max member out of the png structure.
-
-option CHECK_FOR_INVALID_INDEX enables READ_CHECK_FOR_INVALID_INDEX
-option CHECK_FOR_INVALID_INDEX enables WRITE_CHECK_FOR_INVALID_INDEX
-option READ_CHECK_FOR_INVALID_INDEX requires READ CHECK_FOR_INVALID_INDEX
-option WRITE_CHECK_FOR_INVALID_INDEX requires WRITE CHECK_FOR_INVALID_INDEX
-
diff --git a/extern/libpng/include/scripts/pnglibconf.h.prebuilt b/extern/libpng/include/scripts/pnglibconf.h.prebuilt
deleted file mode 100644
index 6facf39aab..0000000000
--- a/extern/libpng/include/scripts/pnglibconf.h.prebuilt
+++ /dev/null
@@ -1,186 +0,0 @@
-
-/* libpng STANDARD API DEFINITION */
-
-/* pnglibconf.h - library build configuration */
-
-/* Libpng 1.5.10 - March 29, 2012 */
-
-/* Copyright (c) 1998-2012 Glenn Randers-Pehrson */
-
-/* This code is released under the libpng license. */
-/* For conditions of distribution and use, see the disclaimer */
-/* and license in png.h */
-
-/* pnglibconf.h */
-/* Derived from: scripts/pnglibconf.dfa */
-/* If you edit this file by hand you must obey the rules expressed in */
-/* pnglibconf.dfa with respect to the dependencies between the following */
-/* symbols.  It is much better to generate a new file using */
-/* scripts/libpngconf.mak */
-
-#ifndef PNGLCONF_H
-#define PNGLCONF_H
-/* settings */
-#define PNG_API_RULE 0
-#define PNG_CALLOC_SUPPORTED
-#define PNG_COST_SHIFT 3
-#define PNG_DEFAULT_READ_MACROS 1
-#define PNG_GAMMA_THRESHOLD_FIXED 5000
-#define PNG_MAX_GAMMA_8 11
-#define PNG_QUANTIZE_BLUE_BITS 5
-#define PNG_QUANTIZE_GREEN_BITS 5
-#define PNG_QUANTIZE_RED_BITS 5
-#define PNG_sCAL_PRECISION 5
-#define PNG_WEIGHT_SHIFT 8
-#define PNG_ZBUF_SIZE 8192
-/* end of settings */
-/* options */
-#define PNG_16BIT_SUPPORTED
-#define PNG_ALIGN_MEMORY_SUPPORTED
-#define PNG_BENIGN_ERRORS_SUPPORTED
-#define PNG_bKGD_SUPPORTED
-#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
-#define PNG_CHECK_cHRM_SUPPORTED
-#define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
-#define PNG_cHRM_SUPPORTED
-#define PNG_CONSOLE_IO_SUPPORTED
-#define PNG_CONVERT_tIME_SUPPORTED
-#define PNG_EASY_ACCESS_SUPPORTED
-/*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
-#define PNG_ERROR_TEXT_SUPPORTED
-#define PNG_FIXED_POINT_SUPPORTED
-#define PNG_FLOATING_ARITHMETIC_SUPPORTED
-#define PNG_FLOATING_POINT_SUPPORTED
-#define PNG_gAMA_SUPPORTED
-#define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-#define PNG_hIST_SUPPORTED
-#define PNG_iCCP_SUPPORTED
-#define PNG_INCH_CONVERSIONS_SUPPORTED
-#define PNG_INFO_IMAGE_SUPPORTED
-#define PNG_IO_STATE_SUPPORTED
-#define PNG_iTXt_SUPPORTED
-#define PNG_MNG_FEATURES_SUPPORTED
-#define PNG_oFFs_SUPPORTED
-#define PNG_pCAL_SUPPORTED
-#define PNG_pHYs_SUPPORTED
-#define PNG_POINTER_INDEXING_SUPPORTED
-#define PNG_PROGRESSIVE_READ_SUPPORTED
-#define PNG_READ_16BIT_SUPPORTED
-#define PNG_READ_ALPHA_MODE_SUPPORTED
-#define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
-#define PNG_READ_BACKGROUND_SUPPORTED
-#define PNG_READ_BGR_SUPPORTED
-#define PNG_READ_bKGD_SUPPORTED
-#define PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
-#define PNG_READ_cHRM_SUPPORTED
-#define PNG_READ_COMPOSITE_NODIV_SUPPORTED
-#define PNG_READ_COMPRESSED_TEXT_SUPPORTED
-#define PNG_READ_EXPAND_16_SUPPORTED
-#define PNG_READ_EXPAND_SUPPORTED
-#define PNG_READ_FILLER_SUPPORTED
-#define PNG_READ_gAMA_SUPPORTED
-#define PNG_READ_GAMMA_SUPPORTED
-#define PNG_READ_GRAY_TO_RGB_SUPPORTED
-#define PNG_READ_hIST_SUPPORTED
-#define PNG_READ_iCCP_SUPPORTED
-#define PNG_READ_INTERLACING_SUPPORTED
-#define PNG_READ_INT_FUNCTIONS_SUPPORTED
-#define PNG_READ_INVERT_ALPHA_SUPPORTED
-#define PNG_READ_INVERT_SUPPORTED
-#define PNG_READ_iTXt_SUPPORTED
-#define PNG_READ_oFFs_SUPPORTED
-#define PNG_READ_OPT_PLTE_SUPPORTED
-#define PNG_READ_PACK_SUPPORTED
-#define PNG_READ_PACKSWAP_SUPPORTED
-#define PNG_READ_pCAL_SUPPORTED
-#define PNG_READ_pHYs_SUPPORTED
-#define PNG_READ_QUANTIZE_SUPPORTED
-#define PNG_READ_RGB_TO_GRAY_SUPPORTED
-#define PNG_READ_sBIT_SUPPORTED
-#define PNG_READ_SCALE_16_TO_8_SUPPORTED
-#define PNG_READ_sCAL_SUPPORTED
-#define PNG_READ_SHIFT_SUPPORTED
-#define PNG_READ_sPLT_SUPPORTED
-#define PNG_READ_sRGB_SUPPORTED
-#define PNG_READ_STRIP_16_TO_8_SUPPORTED
-#define PNG_READ_STRIP_ALPHA_SUPPORTED
-#define PNG_READ_SUPPORTED
-#define PNG_READ_SWAP_ALPHA_SUPPORTED
-#define PNG_READ_SWAP_SUPPORTED
-#define PNG_READ_tEXt_SUPPORTED
-#define PNG_READ_TEXT_SUPPORTED
-#define PNG_READ_tIME_SUPPORTED
-#define PNG_READ_TRANSFORMS_SUPPORTED
-#define PNG_READ_tRNS_SUPPORTED
-#define PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
-#define PNG_READ_USER_CHUNKS_SUPPORTED
-#define PNG_READ_USER_TRANSFORM_SUPPORTED
-#define PNG_READ_zTXt_SUPPORTED
-#define PNG_SAVE_INT_32_SUPPORTED
-#define PNG_sBIT_SUPPORTED
-#define PNG_sCAL_SUPPORTED
-#define PNG_SEQUENTIAL_READ_SUPPORTED
-#define PNG_SET_CHUNK_CACHE_LIMIT_SUPPORTED
-#define PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
-#define PNG_SETJMP_SUPPORTED
-#define PNG_SET_USER_LIMITS_SUPPORTED
-#define PNG_sPLT_SUPPORTED
-#define PNG_sRGB_SUPPORTED
-#define PNG_STDIO_SUPPORTED
-#define PNG_tEXt_SUPPORTED
-#define PNG_TEXT_SUPPORTED
-#define PNG_TIME_RFC1123_SUPPORTED
-#define PNG_tIME_SUPPORTED
-#define PNG_tRNS_SUPPORTED
-#define PNG_UNKNOWN_CHUNKS_SUPPORTED
-#define PNG_USER_CHUNKS_SUPPORTED
-#define PNG_USER_LIMITS_SUPPORTED
-#define PNG_USER_MEM_SUPPORTED
-#define PNG_USER_TRANSFORM_INFO_SUPPORTED
-#define PNG_USER_TRANSFORM_PTR_SUPPORTED
-#define PNG_WARNINGS_SUPPORTED
-#define PNG_WRITE_16BIT_SUPPORTED
-#define PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED
-#define PNG_WRITE_BGR_SUPPORTED
-#define PNG_WRITE_bKGD_SUPPORTED
-#define PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
-#define PNG_WRITE_cHRM_SUPPORTED
-#define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
-#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
-#define PNG_WRITE_FILLER_SUPPORTED
-#define PNG_WRITE_FILTER_SUPPORTED
-#define PNG_WRITE_FLUSH_SUPPORTED
-#define PNG_WRITE_gAMA_SUPPORTED
-#define PNG_WRITE_hIST_SUPPORTED
-#define PNG_WRITE_iCCP_SUPPORTED
-#define PNG_WRITE_INTERLACING_SUPPORTED
-#define PNG_WRITE_INT_FUNCTIONS_SUPPORTED
-#define PNG_WRITE_INVERT_ALPHA_SUPPORTED
-#define PNG_WRITE_INVERT_SUPPORTED
-#define PNG_WRITE_iTXt_SUPPORTED
-#define PNG_WRITE_oFFs_SUPPORTED
-#define PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-#define PNG_WRITE_PACK_SUPPORTED
-#define PNG_WRITE_PACKSWAP_SUPPORTED
-#define PNG_WRITE_pCAL_SUPPORTED
-#define PNG_WRITE_pHYs_SUPPORTED
-#define PNG_WRITE_sBIT_SUPPORTED
-#define PNG_WRITE_sCAL_SUPPORTED
-#define PNG_WRITE_SHIFT_SUPPORTED
-#define PNG_WRITE_sPLT_SUPPORTED
-#define PNG_WRITE_sRGB_SUPPORTED
-#define PNG_WRITE_SUPPORTED
-#define PNG_WRITE_SWAP_ALPHA_SUPPORTED
-#define PNG_WRITE_SWAP_SUPPORTED
-#define PNG_WRITE_tEXt_SUPPORTED
-#define PNG_WRITE_TEXT_SUPPORTED
-#define PNG_WRITE_tIME_SUPPORTED
-#define PNG_WRITE_TRANSFORMS_SUPPORTED
-#define PNG_WRITE_tRNS_SUPPORTED
-#define PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-#define PNG_WRITE_USER_TRANSFORM_SUPPORTED
-#define PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-#define PNG_WRITE_zTXt_SUPPORTED
-#define PNG_zTXt_SUPPORTED
-/* end of options */
-#endif /* PNGLCONF_H */
diff --git a/extern/libpng/include/scripts/pnglibconf.mak b/extern/libpng/include/scripts/pnglibconf.mak
deleted file mode 100755
index c04578f31d..0000000000
--- a/extern/libpng/include/scripts/pnglibconf.mak
+++ /dev/null
@@ -1,58 +0,0 @@
-#!/usr/bin/make -f
-# pnglibconf.mak - standard make lines for pnglibconf.h
-#
-# These lines are copied from Makefile.am, they illustrate
-# how to automate the build of pnglibconf.h from scripts/pnglibconf.dfa
-# given 'awk' and 'sed'
-
-# Override as appropriate, these definitions can be overridden on
-# the make command line (AWK='nawk' for example).
-AWK = gawk
-AWK = mawk
-AWK = nawk
-AWK = one-true-awk
-AWK = awk  # Crashes on SunOS 5.10 - use 'nawk'
-CPP = $(CC) -E # Does not work on SUN OS 5.10 - use /lib/cpp
-SED = sed
-
-COPY = cp
-DELETE = rm -f
-ECHO = echo
-DFA_XTRA = # Appended to scripts/options.awk
-
-# CPPFLAGS should contain the options to control the result,
-# but DEFS and CFLAGS are also supported here, override
-# as appropriate
-DFNFLAGS = $(DEFS) $(CPPFLAGS) $(CFLAGS)
-
-# srcdir is a defacto standard for the location of the source
-srcdir = .
-
-# The standard pnglibconf.h exists as scripts/pnglibconf.h.prebuilt,
-# copy this if the following doesn't work.
-pnglibconf.h: pnglibconf.dfn
-	$(DELETE) $@ dfn.c dfn1.out dfn2.out dfn3.out
-	$(ECHO) '#include "pnglibconf.dfn"' >dfn.c
-	$(CPP) $(DFNFLAGS) dfn.c >dfn1.out
-	$(ECHO) "If 'cpp -e' crashes try /lib/cpp (e.g. CPP='/lib/cpp')" >&2
-	$(SED) -n -e 's|^.*PNG_DEFN_MAGIC *-\(.*\)- *PNG_DEFN_END.*$$|\1|p'\
-	    dfn1.out >dfn2.out
-	$(SED) -e 's| *PNG_JOIN *||g' -e 's| *$$||' dfn2.out >dfn3.out
-	$(COPY) dfn3.out $@
-	$(DELETE) dfn.c dfn1.out dfn2.out dfn3.out
-
-pnglibconf.dfn: $(srcdir)/scripts/pnglibconf.dfa $(srcdir)/scripts/options.awk $(srcdir)/pngconf.h
-	$(DELETE) $@ dfn1.out dfn2.out
-	$(ECHO) "Calling $(AWK) from scripts/pnglibconf.mak" >&2
-	$(ECHO) "If 'awk' crashes try a better awk (e.g. AWK='nawk')" >&2
-	$(AWK) -f $(srcdir)/scripts/options.awk out=dfn1.out version=search\
-		$(srcdir)/pngconf.h $(srcdir)/scripts/pnglibconf.dfa\
-		$(DFA_XTRA) 1>&2
-	$(AWK) -f $(srcdir)/scripts/options.awk out=dfn2.out dfn1.out 1>&2
-	$(COPY) dfn2.out $@
-	$(DELETE) dfn1.out dfn2.out
-
-clean-pnglibconf:
-	$(DELETE) pnglibconf.h pnglibconf.dfn dfn.c dfn1.out dfn2.out dfn3.out
-
-clean: clean-pnglibconf
diff --git a/extern/libpng/include/scripts/pngwin.rc b/extern/libpng/include/scripts/pngwin.rc
deleted file mode 100644
index 9335cbbe03..0000000000
--- a/extern/libpng/include/scripts/pngwin.rc
+++ /dev/null
@@ -1,112 +0,0 @@
-#define PNG_VERSION_INFO_ONLY
-
-#include <windows.h>
-#include "../png.h"
-
-#define _QUOTE(x) # x
-#define QUOTE(x) _QUOTE(x)
-
-#define PNG_LIBPNG_DLLFNAME "LIBPNG"
-
-/* Support deprecated PRIVATEBUILD macro */
-#if defined(PRIVATEBUILD) && !defined(PNG_USER_PRIVATEBUILD)
-#  define PNG_USER_PRIVATEBUILD PRIVATEBUILD
-#endif
-
-#if defined(PNG_USER_DLLFNAME_POSTFIX) && !defined(PNG_USER_PRIVATEBUILD)
-#  error "PNG_USER_PRIVATEBUILD must be defined as a string describing the\
- custom changes made to the library."
-#endif
-
-/* Prioritize PNG_USER_x over PNG_LIBPNG_x */
-#ifdef PNG_USER_DLLFNAME_POSTFIX
-#  undef PNG_LIBPNG_DLLFNAME_POSTFIX
-#  define PNG_LIBPNG_DLLFNAME_POSTFIX PNG_USER_DLLFNAME_POSTFIX
-#endif
-
-#ifdef PNG_USER_VERSIONINFO_COMMENTS
-#  undef PNG_LIBPNG_VERSIONINFO_COMMENTS
-#  define PNG_LIBPNG_VERSIONINFO_COMMENTS PNG_USER_VERSIONINFO_COMMENTS
-#endif
-
-#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
-#  define VS_DEBUG VS_FF_DEBUG
-#  ifndef PNG_LIBPNG_DLLFNAME_POSTFIX
-#    define PNG_LIBPNG_DLLFNAME_POSTFIX "D"
-#  endif /* PNG_LIBPNG_DLLFNAME_POSTFIX */
-#  ifndef PNG_LIBPNG_VERSIONINFO_COMMENTS
-#    define PNG_LIBPNG_VERSIONINFO_COMMENTS "PNG_DEBUG=" QUOTE(PNG_DEBUG)
-#  endif /* PNG_LIBPNG_VERSIONINFO_COMMENTS */
-#else
-#  define VS_DEBUG 0
-#  ifndef PNG_LIBPNG_DLLFNAME_POSTFIX
-#     define PNG_LIBPNG_DLLFNAME_POSTFIX
-#  endif /* PNG_LIBPNG_DLLFNAME_POSTFIX */
-#endif /* defined(DEBUG)... */
-
-#ifdef PNG_USER_PRIVATEBUILD
-#  define VS_PRIVATEBUILD VS_FF_PRIVATEBUILD
-#else
-#  define VS_PRIVATEBUILD 0
-#endif /* PNG_USER_PRIVATEBUILD */
-
-#ifdef PNG_LIBPNG_SPECIALBUILD
-#  define VS_SPECIALBUILD VS_FF_SPECIALBUILD
-#else
-#  define VS_SPECIALBUILD 0
-#endif /* PNG_LIBPNG_BUILD_SPECIAL */
-
-#if ((PNG_LIBPNG_BUILD_BASE_TYPE & PNG_LIBPNG_RELEASE_STATUS_MASK) !=\
-      PNG_LIBPNG_BUILD_STABLE)
-#  define VS_PRERELEASE VS_FF_PRERELEASE
-#  define VS_PATCHED 0
-#else
-#  define VS_PRERELEASE 0
-#  if (PNG_LIBPNG_BUILD_BASE_TYPE & PNG_LIBPNG_BUILD_PATCHED)
-#    define VS_PATCHED VS_FF_PATCHED
-#  else
-#    define VS_PATCHED 0
-#  endif
-#endif
-
-VS_VERSION_INFO VERSIONINFO
-FILEVERSION PNG_LIBPNG_VER_MAJOR, PNG_LIBPNG_VER_MINOR, PNG_LIBPNG_VER_RELEASE, PNG_LIBPNG_VER_BUILD
-PRODUCTVERSION PNG_LIBPNG_VER_MAJOR, PNG_LIBPNG_VER_MINOR, PNG_LIBPNG_VER_RELEASE, PNG_LIBPNG_VER_BUILD
-FILEFLAGSMASK VS_FFI_FILEFLAGSMASK
-FILEFLAGS VS_DEBUG | VS_PRIVATEBUILD | VS_SPECIALBUILD | VS_PRERELEASE | VS_PATCHED
-FILEOS VOS__WINDOWS32
-FILETYPE VFT_DLL
-FILESUBTYPE VFT2_UNKNOWN
-BEGIN
-  BLOCK "StringFileInfo"
-  BEGIN BLOCK "040904E4" /* Language type = U.S English(0x0409) and Character Set = Windows, Multilingual(0x04E4) */
-    BEGIN
-#ifdef PNG_LIBPNG_VERSIONINFO_COMMENTS
-      VALUE "Comments", PNG_LIBPNG_VERSIONINFO_COMMENTS "\000"
-#endif /* PNG_LIBPNG_VERSIONINFO_COMMENTS */
-#ifdef PNG_USER_VERSIONINFO_COMPANYNAME
-      VALUE "CompanyName", PNG_USER_VERSIONINFO_COMPANYNAME "\000"
-#endif /* PNG_USER_VERSIONINFO_COMPANYNAME */
-      VALUE "FileDescription", "PNG image compression library\000"
-      VALUE "FileVersion", PNG_LIBPNG_VER_STRING "\000"
-      VALUE "InternalName", PNG_LIBPNG_DLLFNAME QUOTE(PNG_LIBPNG_VER_DLLNUM) PNG_LIBPNG_DLLFNAME_POSTFIX " (Windows 32 bit)\000"
-      VALUE "LegalCopyright", "\251 1998-2009 Glenn Randers-Pehrson et al.\000"
-#ifdef PNG_USER_VERSIONINFO_LEGALTRADEMARKS
-      VALUE "LegalTrademarks", PNG_USER_VERSIONINFO_LEGALTRADEMARKS "\000"
-#endif /* PNG_USER_VERSIONINFO_LEGALTRADEMARKS */
-      VALUE "OriginalFilename", PNG_LIBPNG_DLLFNAME QUOTE(PNG_LIBPNG_VER_DLLNUM) PNG_LIBPNG_DLLFNAME_POSTFIX ".DLL\000"
-#ifdef PNG_USER_PRIVATEBUILD
-      VALUE "PrivateBuild", PNG_USER_PRIVATEBUILD "\000"
-#endif /* PNG_USER_PRIVATEBUILD */
-      VALUE "ProductName", "LibPNG\000"
-      VALUE "ProductVersion", "1\000"
-#ifdef PNG_LIBPNG_SPECIALBUILD
-      VALUE "SpecialBuild", PNG_LIBPNG_SPECIALBUILD "\000"
-#endif /* PNG_LIBPNG_SPECIALBUILD */
-    END
-  END
-  BLOCK "VarFileInfo"
-  BEGIN
-    VALUE "Translation", 0x0409, 0x04E4
-  END
-END
diff --git a/extern/libpng/include/scripts/smakefile.ppc b/extern/libpng/include/scripts/smakefile.ppc
deleted file mode 100644
index 2e7380b1f9..0000000000
--- a/extern/libpng/include/scripts/smakefile.ppc
+++ /dev/null
@@ -1,34 +0,0 @@
-# Amiga powerUP (TM) Makefile
-# makefile for libpng and SAS C V6.58/7.00 PPC compiler
-# Copyright (C) 1998 by Andreas R. Kleinert
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-CC       = scppc
-CFLAGS   = NOSTKCHK NOSINT OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL IDIR /zlib \
-           OPTLOOP OPTRDEP=8 OPTDEP=8 OPTCOMP=8
-LIBNAME  = libpng.a
-AR       = ppc-amigaos-ar
-AR_FLAGS = cr
-RANLIB   = ppc-amigaos-ranlib
-LDFLAGS  = -r -o
-LDLIBS   =  ../zlib/libzip.a LIB:scppc.a
-LN       = ppc-amigaos-ld
-RM       = delete quiet
-MKDIR    = makedir
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o pngread.o \
-       pngerror.o pngpread.o pngwrite.o pngrtran.o pngwtran.o pngrio.o \
-       pngwio.o pngmem.o
-
-all: $(LIBNAME) pngtest
-
-$(LIBNAME): $(OBJS)
-            $(AR) $(AR_FLAGS) $@ $(OBJS)
-            $(RANLIB) $@
-
-pngtest: pngtest.o $(LIBNAME)
-        $(LN) $(LDFLAGS) pngtest LIB:c_ppc.o pngtest.o $(LIBNAME) $(LDLIBS) \
-LIB:end.o
diff --git a/extern/libpng/include/scripts/sym.dfn b/extern/libpng/include/scripts/sym.dfn
deleted file mode 100644
index f4f13df083..0000000000
--- a/extern/libpng/include/scripts/sym.dfn
+++ /dev/null
@@ -1,15 +0,0 @@
-
-/* sym.dfn - define format of libpng.sym
- *
- * Last changed in libpng version 1.5.0 [January 6, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
-	PNG_DEFN_MAGIC-SYMBOL_PREFIX PNG_JOIN name-PNG_DEFN_END
-
-#include "../png.h"
diff --git a/extern/libpng/include/scripts/symbols.def b/extern/libpng/include/scripts/symbols.def
deleted file mode 100644
index bf958bc606..0000000000
--- a/extern/libpng/include/scripts/symbols.def
+++ /dev/null
@@ -1,242 +0,0 @@
-;--------------------------------------------------------------
-; LIBPNG symbol list as a Win32 DEF file
-; Contains all the symbols that can be exported from libpng
-;--------------------------------------------------------------
-LIBRARY
-
-EXPORTS
-;Version 1.5.10
- png_access_version_number @1
- png_set_sig_bytes @2
- png_sig_cmp @3
- png_create_read_struct @4
- png_create_write_struct @5
- png_get_compression_buffer_size @6
- png_set_compression_buffer_size @7
- png_set_longjmp_fn @8
- png_longjmp @9
- png_reset_zstream @10
- png_create_read_struct_2 @11
- png_create_write_struct_2 @12
- png_write_sig @13
- png_write_chunk @14
- png_write_chunk_start @15
- png_write_chunk_data @16
- png_write_chunk_end @17
- png_create_info_struct @18
- png_info_init_3 @19
- png_write_info_before_PLTE @20
- png_write_info @21
- png_read_info @22
- png_convert_to_rfc1123 @23
- png_convert_from_struct_tm @24
- png_convert_from_time_t @25
- png_set_expand @26
- png_set_expand_gray_1_2_4_to_8 @27
- png_set_palette_to_rgb @28
- png_set_tRNS_to_alpha @29
- png_set_bgr @30
- png_set_gray_to_rgb @31
- png_set_rgb_to_gray @32
- png_set_rgb_to_gray_fixed @33
- png_get_rgb_to_gray_status @34
- png_build_grayscale_palette @35
- png_set_strip_alpha @36
- png_set_swap_alpha @37
- png_set_invert_alpha @38
- png_set_filler @39
- png_set_add_alpha @40
- png_set_swap @41
- png_set_packing @42
- png_set_packswap @43
- png_set_shift @44
- png_set_interlace_handling @45
- png_set_invert_mono @46
- png_set_background @47
- png_set_strip_16 @48
- png_set_quantize @49
- png_set_gamma @50
- png_set_flush @51
- png_write_flush @52
- png_start_read_image @53
- png_read_update_info @54
- png_read_rows @55
- png_read_row @56
- png_read_image @57
- png_write_row @58
- png_write_rows @59
- png_write_image @60
- png_write_end @61
- png_read_end @62
- png_destroy_info_struct @63
- png_destroy_read_struct @64
- png_destroy_write_struct @65
- png_set_crc_action @66
- png_set_filter @67
- png_set_filter_heuristics @68
- png_set_compression_level @69
- png_set_compression_mem_level @70
- png_set_compression_strategy @71
- png_set_compression_window_bits @72
- png_set_compression_method @73
- png_init_io @74
- png_set_error_fn @75
- png_get_error_ptr @76
- png_set_write_fn @77
- png_set_read_fn @78
- png_get_io_ptr @79
- png_set_read_status_fn @80
- png_set_write_status_fn @81
- png_set_mem_fn @82
- png_get_mem_ptr @83
- png_set_read_user_transform_fn @84
- png_set_write_user_transform_fn @85
- png_set_user_transform_info @86
- png_get_user_transform_ptr @87
- png_set_read_user_chunk_fn @88
- png_get_user_chunk_ptr @89
- png_set_progressive_read_fn @90
- png_get_progressive_ptr @91
- png_process_data @92
- png_progressive_combine_row @93
- png_malloc @94
- png_calloc @95
- png_malloc_warn @96
- png_free @97
- png_free_data @98
- png_data_freer @99
- png_malloc_default @100
- png_free_default @101
- png_error @102
- png_chunk_error @103
- png_err @104
- png_warning @105
- png_chunk_warning @106
- png_benign_error @107
- png_chunk_benign_error @108
- png_set_benign_errors @109
- png_get_valid @110
- png_get_rowbytes @111
- png_get_rows @112
- png_set_rows @113
- png_get_channels @114
- png_get_image_width @115
- png_get_image_height @116
- png_get_bit_depth @117
- png_get_color_type @118
- png_get_filter_type @119
- png_get_interlace_type @120
- png_get_compression_type @121
- png_get_pixels_per_meter @122
- png_get_x_pixels_per_meter @123
- png_get_y_pixels_per_meter @124
- png_get_pixel_aspect_ratio @125
- png_get_x_offset_pixels @126
- png_get_y_offset_pixels @127
- png_get_x_offset_microns @128
- png_get_y_offset_microns @129
- png_get_signature @130
- png_get_bKGD @131
- png_set_bKGD @132
- png_get_cHRM @133
- png_get_cHRM_fixed @134
- png_set_cHRM @135
- png_set_cHRM_fixed @136
- png_get_gAMA @137
- png_get_gAMA_fixed @138
- png_set_gAMA @139
- png_set_gAMA_fixed @140
- png_get_hIST @141
- png_set_hIST @142
- png_get_IHDR @143
- png_set_IHDR @144
- png_get_oFFs @145
- png_set_oFFs @146
- png_get_pCAL @147
- png_set_pCAL @148
- png_get_pHYs @149
- png_set_pHYs @150
- png_get_PLTE @151
- png_set_PLTE @152
- png_get_sBIT @153
- png_set_sBIT @154
- png_get_sRGB @155
- png_set_sRGB @156
- png_set_sRGB_gAMA_and_cHRM @157
- png_get_iCCP @158
- png_set_iCCP @159
- png_get_sPLT @160
- png_set_sPLT @161
- png_get_text @162
- png_set_text @163
- png_get_tIME @164
- png_set_tIME @165
- png_get_tRNS @166
- png_set_tRNS @167
- png_get_sCAL @168
- png_get_sCAL_s @169
- png_set_sCAL @170
- png_set_sCAL_s @171
- png_set_keep_unknown_chunks @172
- png_handle_as_unknown @173
- png_set_unknown_chunks @174
- png_set_unknown_chunk_location @175
- png_get_unknown_chunks @176
- png_set_invalid @177
- png_read_png @178
- png_write_png @179
- png_get_copyright @180
- png_get_header_ver @181
- png_get_header_version @182
- png_get_libpng_ver @183
- png_permit_mng_features @184
- png_set_strip_error_numbers @185
- png_set_user_limits @186
- png_get_user_width_max @187
- png_get_user_height_max @188
- png_set_chunk_cache_max @189
- png_get_chunk_cache_max @190
- png_set_chunk_malloc_max @191
- png_get_chunk_malloc_max @192
- png_get_pixels_per_inch @193
- png_get_x_pixels_per_inch @194
- png_get_y_pixels_per_inch @195
- png_get_x_offset_inches @196
- png_get_y_offset_inches @197
- png_get_pHYs_dpi @198
- png_get_io_state @199
- png_get_io_chunk_name @200
- png_get_uint_32 @201
- png_get_uint_16 @202
- png_get_int_32 @203
- png_get_uint_31 @204
- png_save_uint_32 @205
- png_save_int_32 @206
- png_save_uint_16 @207
- png_set_gamma_fixed @208
- png_set_filter_heuristics_fixed @209
- png_get_pixel_aspect_ratio_fixed @210
- png_get_x_offset_inches_fixed @211
- png_get_y_offset_inches_fixed @212
- png_set_sCAL_fixed @213
- png_get_sCAL_fixed @214
- png_set_background_fixed @215
- png_get_io_chunk_type @216
- png_get_current_row_number @217
- png_get_current_pass_number @218
- png_process_data_pause @219
- png_process_data_skip @220
- png_set_expand_16 @221
- png_set_text_compression_level @222
- png_set_text_compression_mem_level @223
- png_set_text_compression_strategy @224
- png_set_text_compression_window_bits @225
- png_set_text_compression_method @226
- png_set_alpha_mode @227
- png_set_alpha_mode_fixed @228
- png_set_scale_16 @229
- png_get_cHRM_XYZ @230
- png_get_cHRM_XYZ_fixed @231
- png_set_cHRM_XYZ @232
- png_set_cHRM_XYZ_fixed @233
- png_set_check_for_invalid_index @234
diff --git a/extern/libpng/include/scripts/symbols.dfn b/extern/libpng/include/scripts/symbols.dfn
deleted file mode 100644
index d790929e7e..0000000000
--- a/extern/libpng/include/scripts/symbols.dfn
+++ /dev/null
@@ -1,57 +0,0 @@
-
-/* symbols.dfn - find all exported symbols
- *
- * Last changed in libpng version 1.5.0 [January 6, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-/* NOTE: making 'symbols.chk' checks both that the exported
- * symbols in the library don't change and (implicitly) that
- * scripts/pnglibconf.h.prebuilt is as expected.  If scripts/pnglibconf.h.prebuilt
- * is remade using scripts/pnglibconf.dfa then this checks the
- * .dfa file too.
- */
-
-#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
-	PNG_DEFN_MAGIC-name @ordinal-PNG_DEFN_END
-#define PNG_REMOVED(ordinal, type, name, args, attributes)\
-	PNG_DEFN_MAGIC-; name @ordinal-PNG_DEFN_END
-#define PNG_EXPORT_LAST_ORDINAL(ordinal)\
-	PNG_DEFN_MAGIC-; @ordinal-PNG_DEFN_END
-
-/* Read the defaults, but use scripts/pnglibconf.h.prebuilt; the 'standard'
- * header file.
- */
-#include "pnglibconf.h.prebuilt"
-#include "../png.h"
-
-/* Some things are turned off by default.  Turn these things
- * on here (by hand) to get the APIs they expose and validate
- * that no harm is done.  This list is the set of options
- * defaulted to 'off' in scripts/pnglibconf.dfa
- *
- * Maintenance: if scripts/pnglibconf.dfa options are changed
- * from, or to, 'off' this needs updating!
- */
-#define PNG_BENIGN_ERRORS_SUPPORTED
-#define PNG_ERROR_NUMBERS_SUPPORTED
-#define PNG_READ_BIG_ENDIAN_SUPPORTED  /* should do nothing! */
-#define PNG_INCH_CONVERSIONS_SUPPORTED
-#define PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
-
-#undef PNG_H
-#include "../png.h"
-
-/* Finally there are a couple of places where option support
- * actually changes the APIs revealed using a #if/#else/#endif
- * test in png.h, test these here.
- */
-#undef  PNG_FLOATING_POINT_SUPPORTED /* Exposes 'fixed' APIs */
-#undef  PNG_ERROR_TEXT_SUPPORTED     /* Exposes unsupported APIs */
-
-#undef PNG_H
-#include "../png.h"
diff --git a/extern/libpng/include/scripts/vers.dfn b/extern/libpng/include/scripts/vers.dfn
deleted file mode 100644
index 89d5f3879e..0000000000
--- a/extern/libpng/include/scripts/vers.dfn
+++ /dev/null
@@ -1,26 +0,0 @@
-
-/* vers.dfn - define format of libpng.vers
- *
- * Last changed in libpng version 1.5.0 [January 6, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#define HEADER PNG_DEFN_MAGIC-PNGLIB_LIBNAME {global:-PNG_DEFN_END
-
-/* NOTE: PNG_JOIN is interpreted by the calling script as a signal to
- * join the two things on either side, so we can do symbol
- * substitution within the name, regular C ## joins the pp-tokens,
- * not their final values.
- */
-#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
-	PNG_DEFN_MAGIC- SYMBOL_PREFIX PNG_JOIN name;-PNG_DEFN_END
-
-#define TRAILER PNG_DEFN_MAGIC-local: *; };-PNG_DEFN_END
-
-HEADER
-#include "../png.h"
-TRAILER
diff --git a/extern/libpng/include/test-pngtest.sh b/extern/libpng/include/test-pngtest.sh
deleted file mode 100755
index bba128b631..0000000000
--- a/extern/libpng/include/test-pngtest.sh
+++ /dev/null
@@ -1,16 +0,0 @@
-#!/bin/sh
-
-echo "Running tests.  For details see pngtest-log.txt"
-
-echo "============ pngtest pngtest.png ==============" > pngtest-log.txt
-
-echo "Running test-pngtest.sh"
-if ./pngtest --strict ${srcdir}/pngtest.png >> pngtest-log.txt 2>&1
-then
-  echo "  PASS: pngtest --strict pngtest.png"
-  err=0
-else
-  echo "  FAIL: pngtest --strict pngtest.png"
-  err=1
-fi
-exit $err
diff --git a/extern/libpng/include/test-pngvalid-full.sh b/extern/libpng/include/test-pngvalid-full.sh
deleted file mode 100755
index f7d1b2b5d5..0000000000
--- a/extern/libpng/include/test-pngvalid-full.sh
+++ /dev/null
@@ -1,21 +0,0 @@
-#!/bin/sh
-#
-# Run a sequence of gamma tests quietly
-err=0
-
-echo >> pngtest-log.txt
-echo "============ pngvalid-full.sh ==============" >> pngtest-log.txt
-
-echo "Running test-pngvalid-full.sh"
-for gamma in threshold transform sbit 16-to-8 background alpha-mode "transform --expand16" "background --expand16" "alpha-mode --expand16"
-do
-   if ./pngvalid "$@" --gamma-$gamma >> pngtest-log.txt 2>&1
-   then
-      echo "  PASS: pngvalid" "$@" "--gamma-$gamma"
-   else
-      echo "  FAIL: pngvalid" "$@" "--gamma-$gamma"
-      err=1
-   fi
-done
-
-exit $err
diff --git a/extern/libpng/include/test-pngvalid-simple.sh b/extern/libpng/include/test-pngvalid-simple.sh
deleted file mode 100755
index 7d4d9d83c2..0000000000
--- a/extern/libpng/include/test-pngvalid-simple.sh
+++ /dev/null
@@ -1,30 +0,0 @@
-#!/bin/sh
-#
-# Run a sequence of tests quietly, without the slow
-# gamma tests
-err=0
-
-echo >> pngtest-log.txt
-echo "============ pngvalid-simple.sh ==============" >> pngtest-log.txt
-echo "Running test-pngvalid-simple.sh"
-# The options to test are:
-#
-# standard tests with and without progressive reading and interlace
-# size images with and without progressive reading
-# transform tests (standard, non-interlaced only)
-#
-for opts in "--standard" "--standard --progressive-read" \
-   "--standard --interlace" "--standard --progressive-read --interlace" \
-   "--size" "--size --progressive-read" \
-   "--transform"
-do
-   if ./pngvalid "$@" $opts >> pngtest-log.txt 2>&1
-   then
-      echo "  PASS: pngvalid" "$@" $opts
-   else
-      echo "  FAIL: pngvalid" "$@" $opts
-      err=1
-   fi
-done
-
-exit $err

From 37e60ffc9746097d6fb0c26b94983affcbe200de Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Fri, 19 Jun 2020 00:05:04 +0200
Subject: [PATCH 50/65] Adjust to vanilla libpng

---
 .appveyor.yml                  |  2 ++
 .github/workflows/ci.yml       |  9 +++++-
 extern/CMakeProject-png.cmake  | 56 +++++++++++++++++++---------------
 src/CMakeLists.txt             |  6 ++--
 src/CMakeProject-texture.cmake |  2 +-
 src/Makefile.am                | 22 ++++++-------
 src/RageSurface_Load_PNG.cpp   | 10 ++----
 src/RageSurface_Save_PNG.cpp   | 10 ++----
 8 files changed, 64 insertions(+), 53 deletions(-)

diff --git a/.appveyor.yml b/.appveyor.yml
index 3d8861b350..e58109f1df 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -24,6 +24,8 @@ init:
 
 install:
 - cmd: >-
+    git submodule update --init
+
     choco install cmake
 
     choco install nsis -version 2.46.0.20150406
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8c153b0af6..930e3c4b17 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,6 +8,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+        with:
+          submodules: true
       - name: Install dependencies
         run: sudo apt-get update && sudo apt-get install -y
           libasound2-dev
@@ -44,6 +46,7 @@ jobs:
           libjack-dev
           libjsoncpp-dev
           libmad0-dev
+          libpng-dev
           libpulse-dev
           libtomcrypt-dev
           libtommath-dev
@@ -65,7 +68,7 @@ jobs:
           -DWITH_SYSTEM_MAD=ON
           -DWITH_SYSTEM_OGG=ON
           -DWITH_SYSTEM_PCRE=ON
-          -DWITH_SYSTEM_PNG=OFF
+          -DWITH_SYSTEM_PNG=ON
           -DWITH_SYSTEM_TOMCRYPT=OFF
           -DWITH_SYSTEM_TOMMATH=ON
           -DWITH_SYSTEM_ZLIB=ON
@@ -77,6 +80,8 @@ jobs:
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v2
+        with:
+          submodules: true
       - name: Install dependencies
         run: brew install
           nasm
@@ -90,6 +95,8 @@ jobs:
     runs-on: windows-latest
     steps:
       - uses: actions/checkout@v2
+        with:
+          submodules: true
       - name: Configure
         run: cmake -B build
       - name: Build
diff --git a/extern/CMakeProject-png.cmake b/extern/CMakeProject-png.cmake
index 8b4a525a4c..ed4d09f79a 100644
--- a/extern/CMakeProject-png.cmake
+++ b/extern/CMakeProject-png.cmake
@@ -3,31 +3,35 @@ if(WITH_SYSTEM_PNG)
   set(PNG_LIBRARIES ${PNG_LIBRARIES} PARENT_SCOPE)
 else()
   set(PNG_SRC
-      "libpng/include/png.c"
-      "libpng/include/pngerror.c"
-      "libpng/include/pngget.c"
-      "libpng/include/pngmem.c"
-      "libpng/include/pngpread.c"
-      "libpng/include/pngread.c"
-      "libpng/include/pngrio.c"
-      "libpng/include/pngrtran.c"
-      "libpng/include/pngrutil.c"
-      "libpng/include/pngset.c"
-      "libpng/include/pngtest.c"
-      "libpng/include/pngtrans.c"
-      "libpng/include/pngwio.c"
-      "libpng/include/pngwrite.c"
-      "libpng/include/pngwtran.c"
-      "libpng/include/pngwutil.c")
+      "libpng/png.c"
+      "libpng/pngerror.c"
+      "libpng/pngget.c"
+      "libpng/pngmem.c"
+      "libpng/pngpread.c"
+      "libpng/pngread.c"
+      "libpng/pngrio.c"
+      "libpng/pngrtran.c"
+      "libpng/pngrutil.c"
+      "libpng/pngset.c"
+      "libpng/pngtest.c"
+      "libpng/pngtrans.c"
+      "libpng/pngwio.c"
+      "libpng/pngwrite.c"
+      "libpng/pngwtran.c"
+      "libpng/pngwutil.c")
+
+  configure_file("libpng/scripts/pnglibconf.h.prebuilt"
+                 "libpng/pnglibconf.h"
+                 COPYONLY)
 
   set(PNG_HPP
-      "libpng/include/png.h"
-      "libpng/include/pngconf.h"
-      "libpng/include/pngdebug.h"
-      "libpng/include/pnginfo.h"
-      "libpng/include/pnglibconf.h"
-      "libpng/include/pngpriv.h"
-      "libpng/include/pngstruct.h")
+      "libpng/png.h"
+      "libpng/pngconf.h"
+      "libpng/pngdebug.h"
+      "libpng/pnginfo.h"
+      "libpng/pnglibconf.h"
+      "libpng/pngpriv.h"
+      "libpng/pngstruct.h")
 
   source_group("" FILES ${PNG_SRC})
   source_group("" FILES ${PNG_HPP})
@@ -42,5 +46,9 @@ else()
     sm_add_compile_definition("png" _CRT_SECURE_NO_WARNINGS)
   endif()
 
-  target_include_directories("png" PUBLIC "zlib")
+  target_include_directories("png" PUBLIC
+    "zlib"
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/libpng>
+    $<INSTALL_INTERFACE:libpng>
+  )
 endif()
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 72cb54a493..398e3e78b1 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -677,8 +677,10 @@ endif()
 if(WIN32)
   # FIXME: This makes no sense...
   #list(APPEND SM_INCLUDE_DIRS ${DIRECTX_INCLUDE_DIR})
-elseif(NOT WITH_SYSTEM_PNG)
-  list(APPEND SM_INCLUDE_DIRS "${SM_EXTERN_DIR}/libpng/include")
+endif()
+
+if(NOT WITH_SYSTEM_PNG)
+  list(APPEND SM_INCLUDE_DIRS "${SM_EXTERN_DIR}/libpng")
 endif()
 
 
diff --git a/src/CMakeProject-texture.cmake b/src/CMakeProject-texture.cmake
index c46cbe14f0..f286adc6df 100644
--- a/src/CMakeProject-texture.cmake
+++ b/src/CMakeProject-texture.cmake
@@ -59,7 +59,7 @@ endif()
 
 if(NOT WITH_SYSTEM_PNG)
   list(APPEND TEXTURE_INCLUDE_DIRS
-              "${SM_EXTERN_DIR}/libpng/include")
+              "${SM_EXTERN_DIR}/libpng")
 endif()
 
 target_include_directories("TextureFontGenerator"
diff --git a/src/Makefile.am b/src/Makefile.am
index 6af42c9c28..9bcb849c06 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -48,17 +48,17 @@ ver.cpp:
 	fi
 
 PNG = \
-../extern/libpng/include/png.c ../extern/libpng/include/.png.h \
-../extern/libpng/include/pngconf.h ../extern/libpng/include/pngdebug.h \
-../extern/libpng/include/pngerror.c ../extern/libpng/include/pngget.c \
-../extern/libpng/include/pnginfo.h ../extern/libpng/include/scripts/pnglibconf.h \
-../extern/libpng/include/pngmem.c ../extern/libpng/include/pngpread.c \
-../extern/libpng/include/pngpriv.h ../extern/libpng/include/pngread.c \
-../extern/libpng/include/pngrio.c ../extern/libpng/include/pngrtran.c \
-../extern/libpng/include/pngrutil.c ../extern/libpng/include/pngset.c \
-../extern/libpng/include/pngstruct.h ../extern/libpng/include/pngtrans.c \
-../extern/libpng/include/pngwio.c ../extern/libpng/include/pngwrite.c \
-../extern/libpng/include/pngwtran.c ../extern/libpng/include/pngwutil.c
+../extern/libpng/png.c ../extern/libpng/.png.h \
+../extern/libpng/pngconf.h ../extern/libpng/pngdebug.h \
+../extern/libpng/pngerror.c ../extern/libpng/pngget.c \
+../extern/libpng/pnginfo.h ../extern/libpng/scripts/pnglibconf.h \
+../extern/libpng/pngmem.c ../extern/libpng/pngpread.c \
+../extern/libpng/pngpriv.h ../extern/libpng/pngread.c \
+../extern/libpng/pngrio.c ../extern/libpng/pngrtran.c \
+../extern/libpng/pngrutil.c ../extern/libpng/pngset.c \
+../extern/libpng/pngstruct.h ../extern/libpng/pngtrans.c \
+../extern/libpng/pngwio.c ../extern/libpng/pngwrite.c \
+../extern/libpng/pngwtran.c ../extern/libpng/pngwutil.c
 
 Screens = \
 Screen.cpp Screen.h ScreenAttract.cpp ScreenAttract.h \
diff --git a/src/RageSurface_Load_PNG.cpp b/src/RageSurface_Load_PNG.cpp
index 4549eccfb8..041667ec73 100644
--- a/src/RageSurface_Load_PNG.cpp
+++ b/src/RageSurface_Load_PNG.cpp
@@ -1,4 +1,7 @@
 #include "global.h"
+
+#include <png.h>
+
 #include "RageSurface_Load_PNG.h"
 #include "RageUtil.h"
 #include "RageLog.h"
@@ -6,17 +9,10 @@
 #include "RageSurface.h"
 
 #if defined(_MSC_VER)
-#include "../extern/libpng/include/png.h"
 #if defined(_BINARY_PNG)
 #pragma comment(lib, "libpng.lib")
 #endif
 #pragma warning(disable: 4611) /* interaction between '_setjmp' and C++ object destruction is non-portable */
-#else
-#ifndef SYSTEM_PNG
-#include "../extern/libpng/include/png.h"
-#else
-#include <png.h>
-#endif // SYSTEM_PNG
 #endif // _MSC_VER
 
 namespace
diff --git a/src/RageSurface_Save_PNG.cpp b/src/RageSurface_Save_PNG.cpp
index d0f2d1d3b9..d7925cf64e 100644
--- a/src/RageSurface_Save_PNG.cpp
+++ b/src/RageSurface_Save_PNG.cpp
@@ -1,4 +1,7 @@
 #include "global.h"
+
+#include <png.h>
+
 #include "RageSurface_Save_PNG.h"
 #include "RageSurface.h"
 #include "RageSurfaceUtils.h"
@@ -7,17 +10,10 @@
 #include "RageUtil.h"
 
 #if defined(_MSC_VER)
-#include "../extern/libpng/include/png.h"
 #if defined(_BINARY_PNG)
 #pragma comment(lib, "libpng.lib")
 #endif
 #pragma warning(disable: 4611) /* interaction between '_setjmp' and C++ object destruction is non-portable */
-#else
-#ifndef SYSTEM_PNG
-#include "../extern/libpng/include/png.h"
-#else
-#include <png.h>
-#endif
 #endif // _MSC_VER
 
 static void SafePngError( png_struct *pPng, const RString &sStr )

From 7ecc7b262b842a1cc1e66c02d597191c43a5b8fd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <m.kroening@hotmail.de>
Date: Sat, 20 Jun 2020 12:14:24 +0200
Subject: [PATCH 51/65] Upgrade libpng to tag v1.6.37

gtk_image_new_from_file results in a segmentation fault with the new version.
---
 extern/libpng                                      | 2 +-
 src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp | 4 +++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/extern/libpng b/extern/libpng
index 5944b94730..a40189cf88 160000
--- a/extern/libpng
+++ b/extern/libpng
@@ -1 +1 @@
-Subproject commit 5944b9473083c5d03c4600ac5d1675394598e41c
+Subproject commit a40189cf881e9f0db80511c382292a5604c3c3d1
diff --git a/src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp b/src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp
index 7b75c90f1c..394dbe1f84 100644
--- a/src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp
+++ b/src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp
@@ -31,7 +31,9 @@ extern "C" const char *Init( int *argc, char ***argv )
 	//gtk_window_set_icon( GTK_WINDOW(window), );
 	gtk_widget_realize(window);
 
-	splash = gtk_image_new_from_file(splash_image_path);
+	splash = gtk_image_new_from_pixbuf(
+		gdk_pixbuf_new_from_file (splash_image_path, nullptr)
+	);
 
 	label = gtk_label_new(nullptr);
 	gtk_label_set_justify(GTK_LABEL(label),GTK_JUSTIFY_CENTER);

From 43ecbf918bfb39cdfb9ac2a029aa714792c3f820 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <m.kroening@hotmail.de>
Date: Sun, 8 Sep 2019 15:52:51 +0200
Subject: [PATCH 52/65] Use standard tomcrypt header

---
 .github/workflows/ci.yml | 3 +--
 src/CMakeLists.txt       | 3 +++
 src/CryptHelpers.h       | 2 +-
 src/CryptManager.cpp     | 5 +++--
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8c153b0af6..e9ba613eef 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -56,7 +56,6 @@ jobs:
           ninja-build
       - name: Configure
         # TODO: png: https://github.com/stepmania/stepmania/issues/1881
-        # TODO: tomcrypt: https://github.com/stepmania/stepmania/issues/1885
         run: cmake -G Ninja -B build
           -DWITH_SYSTEM_FFMPEG=ON
           -DWITH_SYSTEM_GLEW=ON
@@ -66,7 +65,7 @@ jobs:
           -DWITH_SYSTEM_OGG=ON
           -DWITH_SYSTEM_PCRE=ON
           -DWITH_SYSTEM_PNG=OFF
-          -DWITH_SYSTEM_TOMCRYPT=OFF
+          -DWITH_SYSTEM_TOMCRYPT=ON
           -DWITH_SYSTEM_TOMMATH=ON
           -DWITH_SYSTEM_ZLIB=ON
       - name: Build
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 72cb54a493..0dfbdf5f6d 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -681,6 +681,9 @@ elseif(NOT WITH_SYSTEM_PNG)
   list(APPEND SM_INCLUDE_DIRS "${SM_EXTERN_DIR}/libpng/include")
 endif()
 
+if(NOT WITH_SYSTEM_TOMCRYPT)
+  list(APPEND SM_INCLUDE_DIRS "${SM_SRC_DIR}/libtomcrypt/src/headers")
+endif()
 
 target_include_directories("${SM_EXE_NAME}" PUBLIC ${SM_INCLUDE_DIRS})
 
diff --git a/src/CryptHelpers.h b/src/CryptHelpers.h
index 5171f54e2f..c09daf8824 100644
--- a/src/CryptHelpers.h
+++ b/src/CryptHelpers.h
@@ -3,7 +3,7 @@
 
 #if !defined(DISABLE_CRYPTO)
 
-#include "libtomcrypt/src/headers/tomcrypt.h"
+#include <tomcrypt.h>
 
 class PRNGWrapper
 {
diff --git a/src/CryptManager.cpp b/src/CryptManager.cpp
index f61b467760..fa882d51bd 100644
--- a/src/CryptManager.cpp
+++ b/src/CryptManager.cpp
@@ -1,4 +1,7 @@
 #include "global.h"
+
+#include <tomcrypt.h>
+
 #include "CryptManager.h"
 #include "RageUtil.h"
 #include "RageLog.h"
@@ -9,8 +12,6 @@
 #include "LuaReference.h"
 #include "LuaManager.h"
 
-#include "libtomcrypt/src/headers/tomcrypt.h"
-
 CryptManager*	CRYPTMAN	= nullptr;	// global and accessible from anywhere in our program
 
 static const RString PRIVATE_KEY_PATH = "Data/private.rsa";

From 6649a116ed87b8e6a7a1179458563bb8297be716 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Se=C3=A1n=20de=20B=C3=BArca?= <leftmostcat@gmail.com>
Date: Mon, 17 Aug 2015 18:39:50 -0600
Subject: [PATCH 53/65] Update gtk+ LoadingWindow to use gtk3

---
 .github/workflows/ci.yml                           |  4 ++--
 CMake/DefineOptions.cmake                          |  2 +-
 CMake/Modules/FindGTK3.cmake                       |  9 +++++++++
 StepmaniaCore.cmake                                | 14 +++++++-------
 src/CMakeData-arch.cmake                           |  2 +-
 src/CMakeData-gtk.cmake                            |  6 +++---
 src/CMakeLists.txt                                 | 10 +++++-----
 src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp |  6 ++++--
 8 files changed, 32 insertions(+), 21 deletions(-)
 create mode 100644 CMake/Modules/FindGTK3.cmake

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8c153b0af6..59b5755bf6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
           libasound2-dev
           libgl-dev
           libglew-dev
-          libgtk2.0-dev
+          libgtk-3-dev
           libjack-dev
           libmad0-dev
           libpulse-dev
@@ -40,7 +40,7 @@ jobs:
           libasound2-dev
           libgl-dev
           libglew-dev
-          libgtk2.0-dev
+          libgtk-3-dev
           libjack-dev
           libjsoncpp-dev
           libmad0-dev
diff --git a/CMake/DefineOptions.cmake b/CMake/DefineOptions.cmake
index 1c438cce89..75de70aa2d 100644
--- a/CMake/DefineOptions.cmake
+++ b/CMake/DefineOptions.cmake
@@ -96,7 +96,7 @@ elseif(LINUX)
   option(WITH_TTY "Build with Linux TTY Input Support." OFF)
   option(WITH_PROFILING "Build with Profiling Support." OFF)
   option(WITH_GLES2 "Build with OpenGL ES 2.0 Support." ON)
-  option(WITH_GTK2 "Build with GTK2 Support." ON)
+  option(WITH_GTK3 "Build with GTK3 Support." ON)
   option(WITH_PARALLEL_PORT "Build with Parallel Lights I/O Support." OFF)
   option(WITH_CRASH_HANDLER "Build with Crash Handler Support." ON)
   option(WITH_XINERAMA
diff --git a/CMake/Modules/FindGTK3.cmake b/CMake/Modules/FindGTK3.cmake
new file mode 100644
index 0000000000..e3330d8724
--- /dev/null
+++ b/CMake/Modules/FindGTK3.cmake
@@ -0,0 +1,9 @@
+# Use pkg-config to find installed gtk+3 if available
+#
+# Once found, the following are defined:
+#  GTK3_FOUND
+#  GTK3_INCLUDE_DIRS
+#  GTK3_LIBRARIES
+
+include(FindPkgConfig)
+pkg_check_modules(GTK3 gtk+-3.0)
diff --git a/StepmaniaCore.cmake b/StepmaniaCore.cmake
index dcab93cef0..99d5a36a92 100644
--- a/StepmaniaCore.cmake
+++ b/StepmaniaCore.cmake
@@ -365,17 +365,17 @@ elseif(MACOSX)
                    MAC_FRAME_OPENGL
                    MAC_FRAME_SYSTEM)
 elseif(LINUX)
-  if(WITH_GTK2)
-    find_package("GTK2" 2.0)
-    if(${GTK2_FOUND})
-      set(HAS_GTK2 TRUE)
+  if(WITH_GTK3)
+    find_package("GTK3" 2.0)
+    if(${GTK3_FOUND})
+      set(HAS_GTK3 TRUE)
     else()
-      set(HAS_GTK2 FALSE)
+      set(HAS_GTK3 FALSE)
       message(
-        "GTK2 was not found on your system. There will be no loading window.")
+        "GTK3 was not found on your system. There will be no loading window.")
     endif()
   else()
-    set(HAS_GTK2 FALSE)
+    set(HAS_GTK3 FALSE)
   endif()
 
   set(HAS_X11 FALSE)
diff --git a/src/CMakeData-arch.cmake b/src/CMakeData-arch.cmake
index 896506fb50..d9919b9c28 100644
--- a/src/CMakeData-arch.cmake
+++ b/src/CMakeData-arch.cmake
@@ -185,7 +185,7 @@ else()
     list(APPEND SMDATA_ARCH_LOADING_HPP
                 "arch/LoadingWindow/LoadingWindow_MacOSX.h")
   elseif(LINUX)
-    if(GTK2_FOUND)
+    if(GTK3_FOUND)
       list(APPEND SMDATA_ARCH_LOADING_SRC
                   "arch/LoadingWindow/LoadingWindow_Gtk.cpp")
       list(APPEND SMDATA_ARCH_LOADING_HPP
diff --git a/src/CMakeData-gtk.cmake b/src/CMakeData-gtk.cmake
index 10f9ea6b83..80a3817f20 100644
--- a/src/CMakeData-gtk.cmake
+++ b/src/CMakeData-gtk.cmake
@@ -1,4 +1,4 @@
-if(NOT GTK2_FOUND)
+if(NOT GTK3_FOUND)
   return()
 endif()
 
@@ -28,13 +28,13 @@ set_target_properties("GtkModule"
 set_target_properties("GtkModule"
                       PROPERTIES LIBRARY_OUTPUT_DIRECTORY_RELWITHDEBINFO
                                  "${SM_ROOT_DIR}")
-target_link_libraries("GtkModule" ${GTK2_LIBRARIES})
+target_link_libraries("GtkModule" ${GTK3_LIBRARIES})
 set_property(TARGET "GtkModule" PROPERTY FOLDER "Internal Libraries")
 list(APPEND SM_GTK_INCLUDE_DIRS
             "${SM_SRC_DIR}"
             "${SM_SRC_DIR}/generated"
             "${SM_SRC_DIR}/arch/LoadingWindow"
-            "${GTK2_INCLUDE_DIRS}")
+            "${GTK3_INCLUDE_DIRS}")
 
 sm_add_compile_definition("GtkModule" CMAKE_POWERED)
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 72cb54a493..10c427fd0e 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -378,7 +378,7 @@ else() # Linux
     sm_add_compile_definition("${SM_EXE_NAME}" BSD)
   endif()
 
-  if(GTK2_FOUND)
+  if(GTK3_FOUND)
     sm_add_compile_definition("${SM_EXE_NAME}" HAVE_GTK)
   endif()
 
@@ -559,8 +559,8 @@ else() # Unix / Linux TODO: Remember to find and locate the zip archive files.
 
   list(APPEND SMDATA_LINK_LIB "${OPENGL_LIBRARY}")
 
-  if(GTK2_FOUND)
-    list(APPEND SMDATA_LINK_LIB "${GTK2_LIBRARIES}")
+  if(GTK3_FOUND)
+    list(APPEND SMDATA_LINK_LIB "${GTK3_LIBRARIES}")
   endif()
 
   list(APPEND SMDATA_LINK_LIB "${BZIP2_LIBRARIES}" "${CMAKE_THREAD_LIBS_INIT}")
@@ -649,8 +649,8 @@ if(NOT APPLE)
         list(APPEND SM_INCLUDE_DIRS "${SM_FFMPEG_SRC_DIR}" "${SM_FFMPEG_ROOT}")
       endif()
     endif()
-    if(HAS_GTK2)
-      list(APPEND SM_INCLUDE_DIRS "${GTK2_INCLUDE_DIRS}")
+    if(HAS_GTK3)
+      list(APPEND SM_INCLUDE_DIRS "${GTK3_INCLUDE_DIRS}")
     endif()
     if(X11_FOUND)
       list(APPEND SM_INCLUDE_DIRS "${X11_INCLUDE_DIR}")
diff --git a/src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp b/src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp
index 7b75c90f1c..af0cce7ed0 100644
--- a/src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp
+++ b/src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp
@@ -31,7 +31,9 @@ extern "C" const char *Init( int *argc, char ***argv )
 	//gtk_window_set_icon( GTK_WINDOW(window), );
 	gtk_widget_realize(window);
 
-	splash = gtk_image_new_from_file(splash_image_path);
+	splash = gtk_image_new_from_pixbuf(
+		gdk_pixbuf_new_from_file (splash_image_path, nullptr)
+	);
 
 	label = gtk_label_new(nullptr);
 	gtk_label_set_justify(GTK_LABEL(label),GTK_JUSTIFY_CENTER);
@@ -41,7 +43,7 @@ extern "C" const char *Init( int *argc, char ***argv )
 	progressBar = gtk_progress_bar_new();
 	gtk_progress_bar_set_fraction( GTK_PROGRESS_BAR(progressBar), 0.0 );
 
-	vbox = gtk_vbox_new(FALSE,0);
+	vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
 	gtk_container_add(GTK_CONTAINER(window),vbox);
 	gtk_box_pack_start(GTK_BOX(vbox),splash,FALSE,FALSE,0);
 	gtk_box_pack_end(GTK_BOX(vbox),progressBar,FALSE,FALSE,0);

From bfc167fe6d805b37622a96993d2aec5baddf2f52 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Wed, 24 Jun 2020 00:41:52 +0200
Subject: [PATCH 54/65] Replace libpng submodule with source (#2023)

* Replace libpng submodule with source

Taken from 505e70834d35383537b6491e7ae8641f1a4bed1876dbfe361201fc80868d88ca  libpng-1.6.37.tar.xz

* Remove submodule-related config from CI
---
 .appveyor.yml                                 |     2 -
 .github/workflows/ci.yml                      |     6 -
 .gitmodules                                   |     3 -
 extern/libpng                                 |     1 -
 extern/libpng/ANNOUNCE                        |    47 +
 extern/libpng/AUTHORS                         |    45 +
 extern/libpng/CHANGES                         |  6109 ++++++
 extern/libpng/CMakeLists.txt                  |   931 +
 extern/libpng/INSTALL                         |   465 +
 extern/libpng/LICENSE                         |   134 +
 extern/libpng/Makefile.am                     |   393 +
 extern/libpng/Makefile.in                     |  2428 +++
 extern/libpng/README                          |   183 +
 extern/libpng/TODO                            |    23 +
 extern/libpng/TRADEMARK                       |     8 +
 extern/libpng/aclocal.m4                      |  1196 ++
 extern/libpng/arm/arm_init.c                  |   136 +
 extern/libpng/arm/filter_neon.S               |   253 +
 extern/libpng/arm/filter_neon_intrinsics.c    |   402 +
 extern/libpng/arm/palette_neon_intrinsics.c   |   149 +
 extern/libpng/autogen.sh                      |   225 +
 extern/libpng/compile                         |   348 +
 extern/libpng/config.guess                    |  1476 ++
 extern/libpng/config.h.in                     |   126 +
 extern/libpng/config.sub                      |  1801 ++
 extern/libpng/configure                       | 16116 ++++++++++++++++
 extern/libpng/configure.ac                    |   532 +
 extern/libpng/contrib/README.txt              |     5 +
 extern/libpng/contrib/arm-neon/README         |    83 +
 extern/libpng/contrib/arm-neon/android-ndk.c  |    39 +
 extern/libpng/contrib/arm-neon/linux-auxv.c   |   120 +
 extern/libpng/contrib/arm-neon/linux.c        |   161 +
 extern/libpng/contrib/conftest/README         |    49 +
 extern/libpng/contrib/conftest/pngcp.dfa      |    57 +
 extern/libpng/contrib/conftest/read.dfa       |    58 +
 extern/libpng/contrib/conftest/s_read.dfa     |    35 +
 extern/libpng/contrib/conftest/s_write.dfa    |    33 +
 extern/libpng/contrib/conftest/simple.dfa     |    36 +
 extern/libpng/contrib/conftest/write.dfa      |    45 +
 extern/libpng/contrib/examples/README.txt     |    24 +
 extern/libpng/contrib/examples/iccfrompng.c   |   185 +
 extern/libpng/contrib/examples/pngpixel.c     |   371 +
 extern/libpng/contrib/examples/pngtopng.c     |    98 +
 extern/libpng/contrib/examples/simpleover.c   |   648 +
 extern/libpng/contrib/gregbook/COPYING        |   340 +
 extern/libpng/contrib/gregbook/LICENSE        |    50 +
 .../libpng/contrib/gregbook/Makefile.mingw32  |   131 +
 extern/libpng/contrib/gregbook/Makefile.sgi   |   105 +
 extern/libpng/contrib/gregbook/Makefile.unx   |   134 +
 extern/libpng/contrib/gregbook/Makefile.w32   |   114 +
 extern/libpng/contrib/gregbook/README         |   186 +
 extern/libpng/contrib/gregbook/makevms.com    |   132 +
 extern/libpng/contrib/gregbook/readpng.c      |   323 +
 extern/libpng/contrib/gregbook/readpng.h      |    88 +
 extern/libpng/contrib/gregbook/readpng2.c     |   521 +
 extern/libpng/contrib/gregbook/readpng2.h     |   116 +
 extern/libpng/contrib/gregbook/readppm.c      |   188 +
 extern/libpng/contrib/gregbook/rpng-win.c     |   735 +
 extern/libpng/contrib/gregbook/rpng-x.c       |   911 +
 extern/libpng/contrib/gregbook/rpng2-win.c    |  1261 ++
 extern/libpng/contrib/gregbook/rpng2-x.c      |  2143 ++
 extern/libpng/contrib/gregbook/toucan.png     |   Bin 0 -> 12901 bytes
 extern/libpng/contrib/gregbook/wpng.c         |   865 +
 extern/libpng/contrib/gregbook/writepng.c     |   401 +
 extern/libpng/contrib/gregbook/writepng.h     |   133 +
 extern/libpng/contrib/libtests/fakepng.c      |    65 +
 extern/libpng/contrib/libtests/gentests.sh    |   102 +
 extern/libpng/contrib/libtests/makepng.c      |  1941 ++
 extern/libpng/contrib/libtests/pngimage.c     |  1712 ++
 .../libpng/contrib/libtests/pngstest-errors.h |   165 +
 extern/libpng/contrib/libtests/pngstest.c     |  3828 ++++
 extern/libpng/contrib/libtests/pngunknown.c   |  1294 ++
 extern/libpng/contrib/libtests/pngvalid.c     | 12230 ++++++++++++
 extern/libpng/contrib/libtests/readpng.c      |   115 +
 extern/libpng/contrib/libtests/tarith.c       |   999 +
 extern/libpng/contrib/libtests/timepng.c      |   608 +
 extern/libpng/contrib/mips-msa/README         |    83 +
 extern/libpng/contrib/mips-msa/linux.c        |    64 +
 extern/libpng/contrib/oss-fuzz/Dockerfile     |    25 +
 extern/libpng/contrib/oss-fuzz/README.txt     |    37 +
 extern/libpng/contrib/oss-fuzz/build.sh       |    51 +
 .../contrib/oss-fuzz/libpng_read_fuzzer.cc    |   190 +
 .../oss-fuzz/libpng_read_fuzzer.options       |     2 +
 extern/libpng/contrib/oss-fuzz/png.dict       |    39 +
 extern/libpng/contrib/pngminim/README         |     5 +
 extern/libpng/contrib/pngminim/decoder/README |    10 +
 .../libpng/contrib/pngminim/decoder/makefile  |   151 +
 .../contrib/pngminim/decoder/pngusr.dfa       |    40 +
 .../libpng/contrib/pngminim/decoder/pngusr.h  |    23 +
 extern/libpng/contrib/pngminim/encoder/README |    10 +
 .../libpng/contrib/pngminim/encoder/makefile  |   150 +
 .../contrib/pngminim/encoder/pngusr.dfa       |    39 +
 .../libpng/contrib/pngminim/encoder/pngusr.h  |    23 +
 extern/libpng/contrib/pngminim/preader/README |    15 +
 .../libpng/contrib/pngminim/preader/makefile  |   166 +
 .../contrib/pngminim/preader/pngusr.dfa       |    40 +
 .../libpng/contrib/pngminim/preader/pngusr.h  |    23 +
 extern/libpng/contrib/pngminus/CHANGES.txt    |    13 +
 extern/libpng/contrib/pngminus/CMakeLists.txt |    24 +
 extern/libpng/contrib/pngminus/LICENSE.txt    |    22 +
 extern/libpng/contrib/pngminus/Makefile       |    62 +
 extern/libpng/contrib/pngminus/README.txt     |   120 +
 extern/libpng/contrib/pngminus/makevms.com    |    92 +
 extern/libpng/contrib/pngminus/png2pnm.bat    |    41 +
 extern/libpng/contrib/pngminus/png2pnm.c      |   427 +
 extern/libpng/contrib/pngminus/png2pnm.sh     |    42 +
 extern/libpng/contrib/pngminus/pngminus.bat   |     4 +
 extern/libpng/contrib/pngminus/pngminus.sh    |     5 +
 extern/libpng/contrib/pngminus/pnm2png.bat    |    41 +
 extern/libpng/contrib/pngminus/pnm2png.c      |   620 +
 extern/libpng/contrib/pngminus/pnm2png.sh     |    42 +
 extern/libpng/contrib/pngsuite/README         |   107 +
 .../pngsuite/bad_interlace_conversions.txt    |     9 +
 extern/libpng/contrib/pngsuite/basn0g01.png   |   Bin 0 -> 164 bytes
 extern/libpng/contrib/pngsuite/basn0g02.png   |   Bin 0 -> 104 bytes
 extern/libpng/contrib/pngsuite/basn0g04.png   |   Bin 0 -> 145 bytes
 extern/libpng/contrib/pngsuite/basn0g08.png   |   Bin 0 -> 138 bytes
 extern/libpng/contrib/pngsuite/basn0g16.png   |   Bin 0 -> 167 bytes
 extern/libpng/contrib/pngsuite/basn2c08.png   |   Bin 0 -> 145 bytes
 extern/libpng/contrib/pngsuite/basn2c16.png   |   Bin 0 -> 302 bytes
 extern/libpng/contrib/pngsuite/basn3p01.png   |   Bin 0 -> 112 bytes
 extern/libpng/contrib/pngsuite/basn3p02.png   |   Bin 0 -> 146 bytes
 extern/libpng/contrib/pngsuite/basn3p04.png   |   Bin 0 -> 216 bytes
 extern/libpng/contrib/pngsuite/basn3p08.png   |   Bin 0 -> 1286 bytes
 extern/libpng/contrib/pngsuite/basn4a08.png   |   Bin 0 -> 126 bytes
 extern/libpng/contrib/pngsuite/basn4a16.png   |   Bin 0 -> 2206 bytes
 extern/libpng/contrib/pngsuite/basn6a08.png   |   Bin 0 -> 184 bytes
 extern/libpng/contrib/pngsuite/basn6a16.png   |   Bin 0 -> 3435 bytes
 extern/libpng/contrib/pngsuite/ftbbn0g01.png  |   Bin 0 -> 176 bytes
 extern/libpng/contrib/pngsuite/ftbbn0g02.png  |   Bin 0 -> 197 bytes
 extern/libpng/contrib/pngsuite/ftbbn0g04.png  |   Bin 0 -> 429 bytes
 extern/libpng/contrib/pngsuite/ftbbn2c16.png  |   Bin 0 -> 2041 bytes
 extern/libpng/contrib/pngsuite/ftbbn3p08.png  |   Bin 0 -> 1499 bytes
 extern/libpng/contrib/pngsuite/ftbgn2c16.png  |   Bin 0 -> 2041 bytes
 extern/libpng/contrib/pngsuite/ftbgn3p08.png  |   Bin 0 -> 1499 bytes
 extern/libpng/contrib/pngsuite/ftbrn2c08.png  |   Bin 0 -> 1633 bytes
 extern/libpng/contrib/pngsuite/ftbwn0g16.png  |   Bin 0 -> 1313 bytes
 extern/libpng/contrib/pngsuite/ftbwn3p08.png  |   Bin 0 -> 1496 bytes
 extern/libpng/contrib/pngsuite/ftbyn3p08.png  |   Bin 0 -> 1499 bytes
 extern/libpng/contrib/pngsuite/ftp0n0g08.png  |   Bin 0 -> 719 bytes
 extern/libpng/contrib/pngsuite/ftp0n2c08.png  |   Bin 0 -> 1594 bytes
 extern/libpng/contrib/pngsuite/ftp0n3p08.png  |   Bin 0 -> 1476 bytes
 extern/libpng/contrib/pngsuite/ftp1n3p08.png  |   Bin 0 -> 1483 bytes
 extern/libpng/contrib/pngsuite/ibasn0g08.png  |   Bin 0 -> 237 bytes
 extern/libpng/contrib/pngsuite/ibasn0g16.png  |   Bin 0 -> 274 bytes
 extern/libpng/contrib/pngsuite/ibasn2c08.png  |   Bin 0 -> 299 bytes
 extern/libpng/contrib/pngsuite/ibasn2c16.png  |   Bin 0 -> 558 bytes
 extern/libpng/contrib/pngsuite/ibasn3p08.png  |   Bin 0 -> 1492 bytes
 extern/libpng/contrib/pngsuite/ibasn4a08.png  |   Bin 0 -> 198 bytes
 extern/libpng/contrib/pngsuite/ibasn4a16.png  |   Bin 0 -> 2839 bytes
 extern/libpng/contrib/pngsuite/ibasn6a08.png  |   Bin 0 -> 339 bytes
 extern/libpng/contrib/pngsuite/ibasn6a16.png  |   Bin 0 -> 4164 bytes
 extern/libpng/contrib/pngsuite/iftbbn2c16.png |   Bin 0 -> 2624 bytes
 extern/libpng/contrib/pngsuite/iftbbn3p08.png |   Bin 0 -> 1507 bytes
 extern/libpng/contrib/pngsuite/iftbgn2c16.png |   Bin 0 -> 2624 bytes
 extern/libpng/contrib/pngsuite/iftbgn3p08.png |   Bin 0 -> 1507 bytes
 extern/libpng/contrib/pngsuite/iftbrn2c08.png |   Bin 0 -> 1624 bytes
 extern/libpng/contrib/pngsuite/iftbwn0g16.png |   Bin 0 -> 1448 bytes
 extern/libpng/contrib/pngsuite/iftbwn3p08.png |   Bin 0 -> 1507 bytes
 extern/libpng/contrib/pngsuite/iftbyn3p08.png |   Bin 0 -> 1507 bytes
 extern/libpng/contrib/pngsuite/iftp0n0g08.png |   Bin 0 -> 847 bytes
 extern/libpng/contrib/pngsuite/iftp0n2c08.png |   Bin 0 -> 2020 bytes
 extern/libpng/contrib/pngsuite/iftp0n3p08.png |   Bin 0 -> 1495 bytes
 extern/libpng/contrib/pngsuite/iftp1n3p08.png |   Bin 0 -> 1507 bytes
 .../libpng/contrib/pngsuite/interlaced/README |     2 +
 .../contrib/pngsuite/interlaced/ibasn0g01.png |   Bin 0 -> 201 bytes
 .../contrib/pngsuite/interlaced/ibasn0g02.png |   Bin 0 -> 138 bytes
 .../contrib/pngsuite/interlaced/ibasn0g04.png |   Bin 0 -> 231 bytes
 .../contrib/pngsuite/interlaced/ibasn3p01.png |   Bin 0 -> 116 bytes
 .../contrib/pngsuite/interlaced/ibasn3p02.png |   Bin 0 -> 163 bytes
 .../contrib/pngsuite/interlaced/ibasn3p04.png |   Bin 0 -> 288 bytes
 .../pngsuite/interlaced/iftbbn0g01.png        |   Bin 0 -> 214 bytes
 .../pngsuite/interlaced/iftbbn0g02.png        |   Bin 0 -> 211 bytes
 .../pngsuite/interlaced/iftbbn0g04.png        |   Bin 0 -> 489 bytes
 extern/libpng/contrib/powerpc-vsx/README      |    81 +
 extern/libpng/contrib/powerpc-vsx/linux.c     |    57 +
 extern/libpng/contrib/powerpc-vsx/linux_aux.c |    34 +
 .../contrib/testpngs/crashers/bad_iCCP.png    |   Bin 0 -> 321 bytes
 .../contrib/testpngs/crashers/badadler.png    |   Bin 0 -> 67 bytes
 .../contrib/testpngs/crashers/badcrc.png      |   Bin 0 -> 67 bytes
 .../crashers/empty_ancillary_chunks.png       |   Bin 0 -> 730 bytes
 .../contrib/testpngs/crashers/huge_IDAT.png   |   Bin 0 -> 79 bytes
 .../testpngs/crashers/huge_bKGD_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_cHRM_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_eXIf_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_gAMA_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_hIST_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_iCCP_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_iTXt_chunk.png     |   Bin 0 -> 57 bytes
 .../crashers/huge_juNK_unsafe_to_copy.png     |   Bin 0 -> 57 bytes
 .../crashers/huge_juNk_safe_to_copy.png       |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_pCAL_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_pHYs_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_sCAL_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_sPLT_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_sRGB_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_sTER_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_tEXt_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_tIME_chunk.png     |   Bin 0 -> 57 bytes
 .../testpngs/crashers/huge_zTXt_chunk.png     |   Bin 0 -> 57 bytes
 .../contrib/testpngs/gray-1-1.8-tRNS.png      |   Bin 0 -> 325 bytes
 extern/libpng/contrib/testpngs/gray-1-1.8.png |   Bin 0 -> 311 bytes
 .../contrib/testpngs/gray-1-linear-tRNS.png   |   Bin 0 -> 325 bytes
 .../libpng/contrib/testpngs/gray-1-linear.png |   Bin 0 -> 311 bytes
 .../contrib/testpngs/gray-1-sRGB-tRNS.png     |   Bin 0 -> 278 bytes
 .../libpng/contrib/testpngs/gray-1-sRGB.png   |   Bin 0 -> 264 bytes
 .../libpng/contrib/testpngs/gray-1-tRNS.png   |   Bin 0 -> 265 bytes
 extern/libpng/contrib/testpngs/gray-1.png     |   Bin 0 -> 251 bytes
 .../contrib/testpngs/gray-16-1.8-tRNS.png     |   Bin 0 -> 744 bytes
 .../libpng/contrib/testpngs/gray-16-1.8.png   |   Bin 0 -> 744 bytes
 .../contrib/testpngs/gray-16-linear-tRNS.png  |   Bin 0 -> 744 bytes
 .../contrib/testpngs/gray-16-linear.png       |   Bin 0 -> 744 bytes
 .../contrib/testpngs/gray-16-sRGB-tRNS.png    |   Bin 0 -> 697 bytes
 .../libpng/contrib/testpngs/gray-16-sRGB.png  |   Bin 0 -> 697 bytes
 .../libpng/contrib/testpngs/gray-16-tRNS.png  |   Bin 0 -> 684 bytes
 extern/libpng/contrib/testpngs/gray-16.png    |   Bin 0 -> 684 bytes
 .../contrib/testpngs/gray-2-1.8-tRNS.png      |   Bin 0 -> 325 bytes
 extern/libpng/contrib/testpngs/gray-2-1.8.png |   Bin 0 -> 311 bytes
 .../contrib/testpngs/gray-2-linear-tRNS.png   |   Bin 0 -> 325 bytes
 .../libpng/contrib/testpngs/gray-2-linear.png |   Bin 0 -> 311 bytes
 .../contrib/testpngs/gray-2-sRGB-tRNS.png     |   Bin 0 -> 278 bytes
 .../libpng/contrib/testpngs/gray-2-sRGB.png   |   Bin 0 -> 264 bytes
 .../libpng/contrib/testpngs/gray-2-tRNS.png   |   Bin 0 -> 265 bytes
 extern/libpng/contrib/testpngs/gray-2.png     |   Bin 0 -> 251 bytes
 .../contrib/testpngs/gray-4-1.8-tRNS.png      |   Bin 0 -> 327 bytes
 extern/libpng/contrib/testpngs/gray-4-1.8.png |   Bin 0 -> 313 bytes
 .../contrib/testpngs/gray-4-linear-tRNS.png   |   Bin 0 -> 327 bytes
 .../libpng/contrib/testpngs/gray-4-linear.png |   Bin 0 -> 313 bytes
 .../contrib/testpngs/gray-4-sRGB-tRNS.png     |   Bin 0 -> 280 bytes
 .../libpng/contrib/testpngs/gray-4-sRGB.png   |   Bin 0 -> 266 bytes
 .../libpng/contrib/testpngs/gray-4-tRNS.png   |   Bin 0 -> 267 bytes
 extern/libpng/contrib/testpngs/gray-4.png     |   Bin 0 -> 253 bytes
 .../contrib/testpngs/gray-8-1.8-tRNS.png      |   Bin 0 -> 327 bytes
 extern/libpng/contrib/testpngs/gray-8-1.8.png |   Bin 0 -> 313 bytes
 .../contrib/testpngs/gray-8-linear-tRNS.png   |   Bin 0 -> 327 bytes
 .../libpng/contrib/testpngs/gray-8-linear.png |   Bin 0 -> 313 bytes
 .../contrib/testpngs/gray-8-sRGB-tRNS.png     |   Bin 0 -> 280 bytes
 .../libpng/contrib/testpngs/gray-8-sRGB.png   |   Bin 0 -> 266 bytes
 .../libpng/contrib/testpngs/gray-8-tRNS.png   |   Bin 0 -> 267 bytes
 extern/libpng/contrib/testpngs/gray-8.png     |   Bin 0 -> 253 bytes
 .../contrib/testpngs/gray-alpha-16-1.8.png    |   Bin 0 -> 919 bytes
 .../contrib/testpngs/gray-alpha-16-linear.png |   Bin 0 -> 919 bytes
 .../contrib/testpngs/gray-alpha-16-sRGB.png   |   Bin 0 -> 872 bytes
 .../libpng/contrib/testpngs/gray-alpha-16.png |   Bin 0 -> 859 bytes
 .../contrib/testpngs/gray-alpha-8-1.8.png     |   Bin 0 -> 744 bytes
 .../contrib/testpngs/gray-alpha-8-linear.png  |   Bin 0 -> 744 bytes
 .../contrib/testpngs/gray-alpha-8-sRGB.png    |   Bin 0 -> 697 bytes
 .../libpng/contrib/testpngs/gray-alpha-8.png  |   Bin 0 -> 684 bytes
 extern/libpng/contrib/testpngs/makepngs.sh    |    94 +
 .../contrib/testpngs/palette-1-1.8-tRNS.png   |   Bin 0 -> 342 bytes
 .../libpng/contrib/testpngs/palette-1-1.8.png |   Bin 0 -> 329 bytes
 .../testpngs/palette-1-linear-tRNS.png        |   Bin 0 -> 342 bytes
 .../contrib/testpngs/palette-1-linear.png     |   Bin 0 -> 329 bytes
 .../contrib/testpngs/palette-1-sRGB-tRNS.png  |   Bin 0 -> 295 bytes
 .../contrib/testpngs/palette-1-sRGB.png       |   Bin 0 -> 282 bytes
 .../contrib/testpngs/palette-1-tRNS.png       |   Bin 0 -> 282 bytes
 extern/libpng/contrib/testpngs/palette-1.png  |   Bin 0 -> 269 bytes
 .../contrib/testpngs/palette-2-1.8-tRNS.png   |   Bin 0 -> 350 bytes
 .../libpng/contrib/testpngs/palette-2-1.8.png |   Bin 0 -> 335 bytes
 .../testpngs/palette-2-linear-tRNS.png        |   Bin 0 -> 350 bytes
 .../contrib/testpngs/palette-2-linear.png     |   Bin 0 -> 335 bytes
 .../contrib/testpngs/palette-2-sRGB-tRNS.png  |   Bin 0 -> 303 bytes
 .../contrib/testpngs/palette-2-sRGB.png       |   Bin 0 -> 288 bytes
 .../contrib/testpngs/palette-2-tRNS.png       |   Bin 0 -> 290 bytes
 extern/libpng/contrib/testpngs/palette-2.png  |   Bin 0 -> 275 bytes
 .../contrib/testpngs/palette-4-1.8-tRNS.png   |   Bin 0 -> 400 bytes
 .../libpng/contrib/testpngs/palette-4-1.8.png |   Bin 0 -> 373 bytes
 .../testpngs/palette-4-linear-tRNS.png        |   Bin 0 -> 400 bytes
 .../contrib/testpngs/palette-4-linear.png     |   Bin 0 -> 373 bytes
 .../contrib/testpngs/palette-4-sRGB-tRNS.png  |   Bin 0 -> 353 bytes
 .../contrib/testpngs/palette-4-sRGB.png       |   Bin 0 -> 326 bytes
 .../contrib/testpngs/palette-4-tRNS.png       |   Bin 0 -> 340 bytes
 extern/libpng/contrib/testpngs/palette-4.png  |   Bin 0 -> 313 bytes
 .../contrib/testpngs/palette-8-1.8-tRNS.png   |   Bin 0 -> 1360 bytes
 .../libpng/contrib/testpngs/palette-8-1.8.png |   Bin 0 -> 1093 bytes
 .../testpngs/palette-8-linear-tRNS.png        |   Bin 0 -> 1360 bytes
 .../contrib/testpngs/palette-8-linear.png     |   Bin 0 -> 1093 bytes
 .../contrib/testpngs/palette-8-sRGB-tRNS.png  |   Bin 0 -> 1313 bytes
 .../contrib/testpngs/palette-8-sRGB.png       |   Bin 0 -> 1046 bytes
 .../contrib/testpngs/palette-8-tRNS.png       |   Bin 0 -> 1300 bytes
 extern/libpng/contrib/testpngs/palette-8.png  |   Bin 0 -> 1033 bytes
 .../contrib/testpngs/rgb-16-1.8-tRNS.png      |   Bin 0 -> 1211 bytes
 extern/libpng/contrib/testpngs/rgb-16-1.8.png |   Bin 0 -> 1211 bytes
 .../contrib/testpngs/rgb-16-linear-tRNS.png   |   Bin 0 -> 1211 bytes
 .../libpng/contrib/testpngs/rgb-16-linear.png |   Bin 0 -> 1211 bytes
 .../contrib/testpngs/rgb-16-sRGB-tRNS.png     |   Bin 0 -> 1164 bytes
 .../libpng/contrib/testpngs/rgb-16-sRGB.png   |   Bin 0 -> 1164 bytes
 .../libpng/contrib/testpngs/rgb-16-tRNS.png   |   Bin 0 -> 1151 bytes
 extern/libpng/contrib/testpngs/rgb-16.png     |   Bin 0 -> 1151 bytes
 .../contrib/testpngs/rgb-8-1.8-tRNS.png       |   Bin 0 -> 837 bytes
 extern/libpng/contrib/testpngs/rgb-8-1.8.png  |   Bin 0 -> 819 bytes
 .../contrib/testpngs/rgb-8-linear-tRNS.png    |   Bin 0 -> 837 bytes
 .../libpng/contrib/testpngs/rgb-8-linear.png  |   Bin 0 -> 819 bytes
 .../contrib/testpngs/rgb-8-sRGB-tRNS.png      |   Bin 0 -> 790 bytes
 extern/libpng/contrib/testpngs/rgb-8-sRGB.png |   Bin 0 -> 772 bytes
 extern/libpng/contrib/testpngs/rgb-8-tRNS.png |   Bin 0 -> 777 bytes
 extern/libpng/contrib/testpngs/rgb-8.png      |   Bin 0 -> 759 bytes
 .../contrib/testpngs/rgb-alpha-16-1.8.png     |   Bin 0 -> 1437 bytes
 .../contrib/testpngs/rgb-alpha-16-linear.png  |   Bin 0 -> 1437 bytes
 .../contrib/testpngs/rgb-alpha-16-sRGB.png    |   Bin 0 -> 1390 bytes
 .../libpng/contrib/testpngs/rgb-alpha-16.png  |   Bin 0 -> 1377 bytes
 .../contrib/testpngs/rgb-alpha-8-1.8.png      |   Bin 0 -> 919 bytes
 .../contrib/testpngs/rgb-alpha-8-linear.png   |   Bin 0 -> 919 bytes
 .../contrib/testpngs/rgb-alpha-8-sRGB.png     |   Bin 0 -> 872 bytes
 .../libpng/contrib/testpngs/rgb-alpha-8.png   |   Bin 0 -> 859 bytes
 extern/libpng/contrib/tools/README.txt        |    27 +
 extern/libpng/contrib/tools/checksum-icc.c    |   102 +
 extern/libpng/contrib/tools/chkfmt            |   144 +
 extern/libpng/contrib/tools/cvtcolor.c        |   188 +
 extern/libpng/contrib/tools/genpng.c          |   881 +
 extern/libpng/contrib/tools/intgamma.sh       |   110 +
 extern/libpng/contrib/tools/makesRGB.c        |   430 +
 extern/libpng/contrib/tools/png-fix-itxt.c    |   164 +
 extern/libpng/contrib/tools/pngcp.c           |  2453 +++
 extern/libpng/contrib/tools/pngfix.c          |  4049 ++++
 extern/libpng/contrib/tools/reindent          |    25 +
 extern/libpng/contrib/tools/sRGB.h            |    48 +
 extern/libpng/contrib/visupng/PngFile.c       |   454 +
 extern/libpng/contrib/visupng/PngFile.h       |    30 +
 extern/libpng/contrib/visupng/README.txt      |    61 +
 extern/libpng/contrib/visupng/VisualPng.c     |   978 +
 extern/libpng/contrib/visupng/VisualPng.dsp   |   147 +
 extern/libpng/contrib/visupng/VisualPng.dsw   |    29 +
 extern/libpng/contrib/visupng/VisualPng.ico   |   Bin 0 -> 766 bytes
 extern/libpng/contrib/visupng/VisualPng.png   |   Bin 0 -> 208 bytes
 extern/libpng/contrib/visupng/VisualPng.rc    |   152 +
 extern/libpng/contrib/visupng/cexcept.h       |   248 +
 extern/libpng/contrib/visupng/resource.h      |    23 +
 extern/libpng/depcomp                         |   791 +
 extern/libpng/example.c                       |  1040 +
 extern/libpng/install-sh                      |   518 +
 extern/libpng/intel/filter_sse2_intrinsics.c  |   391 +
 extern/libpng/intel/intel_init.c              |    52 +
 extern/libpng/libpng-config.in                |   127 +
 extern/libpng/libpng-manual.txt               |  5409 ++++++
 extern/libpng/libpng.3                        |  6052 ++++++
 extern/libpng/libpng.pc.in                    |    12 +
 extern/libpng/libpngpf.3                      |    24 +
 extern/libpng/ltmain.sh                       | 11147 +++++++++++
 extern/libpng/mips/filter_msa_intrinsics.c    |   808 +
 extern/libpng/mips/mips_init.c                |   130 +
 extern/libpng/missing                         |   215 +
 extern/libpng/png.5                           |    84 +
 extern/libpng/png.c                           |  4607 +++++
 extern/libpng/png.h                           |  3247 ++++
 extern/libpng/pngbar.jpg                      |   Bin 0 -> 2498 bytes
 extern/libpng/pngbar.png                      |   Bin 0 -> 2399 bytes
 extern/libpng/pngconf.h                       |   623 +
 extern/libpng/pngdebug.h                      |   153 +
 extern/libpng/pngerror.c                      |   963 +
 extern/libpng/pngget.c                        |  1249 ++
 extern/libpng/pnginfo.h                       |   267 +
 extern/libpng/pngmem.c                        |   284 +
 extern/libpng/pngnow.png                      |   Bin 0 -> 2069 bytes
 extern/libpng/pngpread.c                      |  1096 ++
 extern/libpng/pngpriv.h                       |  2152 +++
 extern/libpng/pngread.c                       |  4225 ++++
 extern/libpng/pngrio.c                        |   120 +
 extern/libpng/pngrtran.c                      |  5044 +++++
 extern/libpng/pngrutil.c                      |  4681 +++++
 extern/libpng/pngset.c                        |  1802 ++
 extern/libpng/pngstruct.h                     |   489 +
 extern/libpng/pngtest.c                       |  2158 +++
 extern/libpng/pngtest.png                     |   Bin 0 -> 8759 bytes
 extern/libpng/pngtrans.c                      |   864 +
 extern/libpng/pngusr.dfa                      |    14 +
 extern/libpng/pngwio.c                        |   168 +
 extern/libpng/pngwrite.c                      |  2395 +++
 extern/libpng/pngwtran.c                      |   575 +
 extern/libpng/pngwutil.c                      |  2781 +++
 extern/libpng/powerpc/filter_vsx_intrinsics.c |   768 +
 extern/libpng/powerpc/powerpc_init.c          |   126 +
 extern/libpng/projects/owatcom/libpng.tgt     |   383 +
 extern/libpng/projects/owatcom/libpng.wpj     |   112 +
 extern/libpng/projects/owatcom/pngconfig.mak  |   160 +
 extern/libpng/projects/owatcom/pngstest.tgt   |   219 +
 extern/libpng/projects/owatcom/pngtest.tgt    |   179 +
 extern/libpng/projects/owatcom/pngvalid.tgt   |   210 +
 extern/libpng/projects/visualc71/PRJ0041.mak  |    21 +
 extern/libpng/projects/visualc71/README.txt   |    58 +
 .../libpng/projects/visualc71/README_zlib.txt |    44 +
 extern/libpng/projects/visualc71/libpng.sln   |    60 +
 .../libpng/projects/visualc71/libpng.vcproj   |   419 +
 .../libpng/projects/visualc71/pngtest.vcproj  |   267 +
 extern/libpng/projects/visualc71/zlib.vcproj  |   391 +
 extern/libpng/projects/vstudio/README.txt     |    87 +
 .../projects/vstudio/libpng/libpng.vcxproj    |   234 +
 .../vstudio/pnglibconf/pnglibconf.vcxproj     |    61 +
 .../vstudio/pngstest/pngstest.vcxproj         |   219 +
 .../projects/vstudio/pngtest/pngtest.vcxproj  |   220 +
 .../vstudio/pngunknown/pngunknown.vcxproj     |   219 +
 .../vstudio/pngvalid/pngvalid.vcxproj         |   219 +
 extern/libpng/projects/vstudio/vstudio.sln    |   109 +
 extern/libpng/projects/vstudio/zlib.props     |    57 +
 .../libpng/projects/vstudio/zlib/zlib.vcxproj |   175 +
 extern/libpng/scripts/README.txt              |    79 +
 extern/libpng/scripts/SCOPTIONS.ppc           |     7 +
 extern/libpng/scripts/checksym.awk            |   173 +
 extern/libpng/scripts/descrip.mms             |    52 +
 extern/libpng/scripts/dfn.awk                 |   203 +
 extern/libpng/scripts/genchk.cmake.in         |    37 +
 extern/libpng/scripts/genout.cmake.in         |    93 +
 extern/libpng/scripts/gensrc.cmake.in         |   138 +
 extern/libpng/scripts/intprefix.c             |    22 +
 extern/libpng/scripts/libpng-config-body.in   |    96 +
 extern/libpng/scripts/libpng-config-head.in   |    24 +
 extern/libpng/scripts/libpng.pc.in            |    10 +
 extern/libpng/scripts/libtool.m4              |  8369 ++++++++
 extern/libpng/scripts/ltoptions.m4            |   437 +
 extern/libpng/scripts/ltsugar.m4              |   124 +
 extern/libpng/scripts/ltversion.m4            |    23 +
 extern/libpng/scripts/lt~obsolete.m4          |    99 +
 extern/libpng/scripts/macro.lst               |     3 +
 extern/libpng/scripts/makefile.32sunu         |   244 +
 extern/libpng/scripts/makefile.64sunu         |   244 +
 extern/libpng/scripts/makefile.acorn          |    57 +
 extern/libpng/scripts/makefile.aix            |   116 +
 extern/libpng/scripts/makefile.amiga          |    58 +
 extern/libpng/scripts/makefile.atari          |    71 +
 extern/libpng/scripts/makefile.bc32           |   158 +
 extern/libpng/scripts/makefile.beos           |   222 +
 extern/libpng/scripts/makefile.cegcc          |   116 +
 extern/libpng/scripts/makefile.clang          |    87 +
 extern/libpng/scripts/makefile.clang-asan     |    87 +
 extern/libpng/scripts/makefile.darwin         |   225 +
 extern/libpng/scripts/makefile.dec            |   210 +
 extern/libpng/scripts/makefile.dj2            |    72 +
 extern/libpng/scripts/makefile.freebsd        |    69 +
 extern/libpng/scripts/makefile.gcc            |    87 +
 extern/libpng/scripts/makefile.gcc-asan       |    87 +
 extern/libpng/scripts/makefile.hp64           |   231 +
 extern/libpng/scripts/makefile.hpgcc          |   234 +
 extern/libpng/scripts/makefile.hpux           |   229 +
 extern/libpng/scripts/makefile.ibmc           |    90 +
 extern/libpng/scripts/makefile.intel          |   115 +
 extern/libpng/scripts/makefile.linux          |   246 +
 extern/libpng/scripts/makefile.linux-opt      |   265 +
 extern/libpng/scripts/makefile.mips           |   103 +
 extern/libpng/scripts/makefile.msys           |   202 +
 extern/libpng/scripts/makefile.netbsd         |    55 +
 extern/libpng/scripts/makefile.openbsd        |    86 +
 extern/libpng/scripts/makefile.sco            |   226 +
 extern/libpng/scripts/makefile.sggcc          |   236 +
 extern/libpng/scripts/makefile.sgi            |   237 +
 extern/libpng/scripts/makefile.so9            |   247 +
 extern/libpng/scripts/makefile.solaris        |   243 +
 extern/libpng/scripts/makefile.std            |   134 +
 extern/libpng/scripts/makefile.sunos          |   115 +
 extern/libpng/scripts/makefile.vcwin32        |   113 +
 extern/libpng/scripts/makevms.com             |   142 +
 extern/libpng/scripts/options.awk             |   898 +
 extern/libpng/scripts/pnglibconf.dfa          |   920 +
 extern/libpng/scripts/pnglibconf.h.prebuilt   |   219 +
 extern/libpng/scripts/pnglibconf.mak          |    55 +
 extern/libpng/scripts/pngwin.rc               |   112 +
 extern/libpng/scripts/prefix.c                |    24 +
 extern/libpng/scripts/smakefile.ppc           |    34 +
 extern/libpng/scripts/sym.c                   |    15 +
 extern/libpng/scripts/symbols.c               |    58 +
 extern/libpng/scripts/symbols.def             |   255 +
 extern/libpng/scripts/test.cmake.in           |    31 +
 extern/libpng/scripts/vers.c                  |    19 +
 extern/libpng/test-driver                     |   148 +
 extern/libpng/tests/pngimage-full             |     2 +
 extern/libpng/tests/pngimage-quick            |     2 +
 extern/libpng/tests/pngstest                  |    54 +
 extern/libpng/tests/pngstest-1.8              |     2 +
 extern/libpng/tests/pngstest-1.8-alpha        |     2 +
 extern/libpng/tests/pngstest-linear           |     2 +
 extern/libpng/tests/pngstest-linear-alpha     |     2 +
 extern/libpng/tests/pngstest-none             |     2 +
 extern/libpng/tests/pngstest-none-alpha       |     2 +
 extern/libpng/tests/pngstest-sRGB             |     2 +
 extern/libpng/tests/pngstest-sRGB-alpha       |     2 +
 extern/libpng/tests/pngtest                   |     2 +
 extern/libpng/tests/pngtest-badpngs           |    13 +
 extern/libpng/tests/pngunknown-IDAT           |     2 +
 extern/libpng/tests/pngunknown-discard        |     2 +
 extern/libpng/tests/pngunknown-if-safe        |     2 +
 extern/libpng/tests/pngunknown-sAPI           |     2 +
 extern/libpng/tests/pngunknown-sTER           |     2 +
 extern/libpng/tests/pngunknown-save           |     2 +
 extern/libpng/tests/pngunknown-vpAg           |     2 +
 extern/libpng/tests/pngvalid-gamma-16-to-8    |     2 +
 extern/libpng/tests/pngvalid-gamma-alpha-mode |     2 +
 extern/libpng/tests/pngvalid-gamma-background |     2 +
 .../tests/pngvalid-gamma-expand16-alpha-mode  |     2 +
 .../tests/pngvalid-gamma-expand16-background  |     2 +
 .../tests/pngvalid-gamma-expand16-transform   |     2 +
 extern/libpng/tests/pngvalid-gamma-sbit       |     2 +
 extern/libpng/tests/pngvalid-gamma-threshold  |     2 +
 extern/libpng/tests/pngvalid-gamma-transform  |     2 +
 .../pngvalid-progressive-interlace-standard   |     2 +
 extern/libpng/tests/pngvalid-progressive-size |     2 +
 .../tests/pngvalid-progressive-standard       |     2 +
 extern/libpng/tests/pngvalid-standard         |     2 +
 extern/libpng/tests/pngvalid-transform        |     2 +
 497 files changed, 171818 insertions(+), 12 deletions(-)
 delete mode 160000 extern/libpng
 create mode 100644 extern/libpng/ANNOUNCE
 create mode 100644 extern/libpng/AUTHORS
 create mode 100644 extern/libpng/CHANGES
 create mode 100644 extern/libpng/CMakeLists.txt
 create mode 100644 extern/libpng/INSTALL
 create mode 100644 extern/libpng/LICENSE
 create mode 100644 extern/libpng/Makefile.am
 create mode 100644 extern/libpng/Makefile.in
 create mode 100644 extern/libpng/README
 create mode 100644 extern/libpng/TODO
 create mode 100644 extern/libpng/TRADEMARK
 create mode 100644 extern/libpng/aclocal.m4
 create mode 100644 extern/libpng/arm/arm_init.c
 create mode 100644 extern/libpng/arm/filter_neon.S
 create mode 100644 extern/libpng/arm/filter_neon_intrinsics.c
 create mode 100644 extern/libpng/arm/palette_neon_intrinsics.c
 create mode 100755 extern/libpng/autogen.sh
 create mode 100755 extern/libpng/compile
 create mode 100755 extern/libpng/config.guess
 create mode 100644 extern/libpng/config.h.in
 create mode 100755 extern/libpng/config.sub
 create mode 100755 extern/libpng/configure
 create mode 100644 extern/libpng/configure.ac
 create mode 100644 extern/libpng/contrib/README.txt
 create mode 100644 extern/libpng/contrib/arm-neon/README
 create mode 100644 extern/libpng/contrib/arm-neon/android-ndk.c
 create mode 100644 extern/libpng/contrib/arm-neon/linux-auxv.c
 create mode 100644 extern/libpng/contrib/arm-neon/linux.c
 create mode 100644 extern/libpng/contrib/conftest/README
 create mode 100644 extern/libpng/contrib/conftest/pngcp.dfa
 create mode 100644 extern/libpng/contrib/conftest/read.dfa
 create mode 100644 extern/libpng/contrib/conftest/s_read.dfa
 create mode 100644 extern/libpng/contrib/conftest/s_write.dfa
 create mode 100644 extern/libpng/contrib/conftest/simple.dfa
 create mode 100644 extern/libpng/contrib/conftest/write.dfa
 create mode 100644 extern/libpng/contrib/examples/README.txt
 create mode 100644 extern/libpng/contrib/examples/iccfrompng.c
 create mode 100644 extern/libpng/contrib/examples/pngpixel.c
 create mode 100644 extern/libpng/contrib/examples/pngtopng.c
 create mode 100644 extern/libpng/contrib/examples/simpleover.c
 create mode 100644 extern/libpng/contrib/gregbook/COPYING
 create mode 100644 extern/libpng/contrib/gregbook/LICENSE
 create mode 100644 extern/libpng/contrib/gregbook/Makefile.mingw32
 create mode 100644 extern/libpng/contrib/gregbook/Makefile.sgi
 create mode 100644 extern/libpng/contrib/gregbook/Makefile.unx
 create mode 100644 extern/libpng/contrib/gregbook/Makefile.w32
 create mode 100644 extern/libpng/contrib/gregbook/README
 create mode 100644 extern/libpng/contrib/gregbook/makevms.com
 create mode 100644 extern/libpng/contrib/gregbook/readpng.c
 create mode 100644 extern/libpng/contrib/gregbook/readpng.h
 create mode 100644 extern/libpng/contrib/gregbook/readpng2.c
 create mode 100644 extern/libpng/contrib/gregbook/readpng2.h
 create mode 100644 extern/libpng/contrib/gregbook/readppm.c
 create mode 100644 extern/libpng/contrib/gregbook/rpng-win.c
 create mode 100644 extern/libpng/contrib/gregbook/rpng-x.c
 create mode 100644 extern/libpng/contrib/gregbook/rpng2-win.c
 create mode 100644 extern/libpng/contrib/gregbook/rpng2-x.c
 create mode 100644 extern/libpng/contrib/gregbook/toucan.png
 create mode 100644 extern/libpng/contrib/gregbook/wpng.c
 create mode 100644 extern/libpng/contrib/gregbook/writepng.c
 create mode 100644 extern/libpng/contrib/gregbook/writepng.h
 create mode 100644 extern/libpng/contrib/libtests/fakepng.c
 create mode 100755 extern/libpng/contrib/libtests/gentests.sh
 create mode 100644 extern/libpng/contrib/libtests/makepng.c
 create mode 100644 extern/libpng/contrib/libtests/pngimage.c
 create mode 100644 extern/libpng/contrib/libtests/pngstest-errors.h
 create mode 100644 extern/libpng/contrib/libtests/pngstest.c
 create mode 100644 extern/libpng/contrib/libtests/pngunknown.c
 create mode 100644 extern/libpng/contrib/libtests/pngvalid.c
 create mode 100644 extern/libpng/contrib/libtests/readpng.c
 create mode 100644 extern/libpng/contrib/libtests/tarith.c
 create mode 100644 extern/libpng/contrib/libtests/timepng.c
 create mode 100644 extern/libpng/contrib/mips-msa/README
 create mode 100644 extern/libpng/contrib/mips-msa/linux.c
 create mode 100644 extern/libpng/contrib/oss-fuzz/Dockerfile
 create mode 100644 extern/libpng/contrib/oss-fuzz/README.txt
 create mode 100755 extern/libpng/contrib/oss-fuzz/build.sh
 create mode 100644 extern/libpng/contrib/oss-fuzz/libpng_read_fuzzer.cc
 create mode 100644 extern/libpng/contrib/oss-fuzz/libpng_read_fuzzer.options
 create mode 100644 extern/libpng/contrib/oss-fuzz/png.dict
 create mode 100644 extern/libpng/contrib/pngminim/README
 create mode 100644 extern/libpng/contrib/pngminim/decoder/README
 create mode 100644 extern/libpng/contrib/pngminim/decoder/makefile
 create mode 100644 extern/libpng/contrib/pngminim/decoder/pngusr.dfa
 create mode 100644 extern/libpng/contrib/pngminim/decoder/pngusr.h
 create mode 100644 extern/libpng/contrib/pngminim/encoder/README
 create mode 100644 extern/libpng/contrib/pngminim/encoder/makefile
 create mode 100644 extern/libpng/contrib/pngminim/encoder/pngusr.dfa
 create mode 100644 extern/libpng/contrib/pngminim/encoder/pngusr.h
 create mode 100644 extern/libpng/contrib/pngminim/preader/README
 create mode 100644 extern/libpng/contrib/pngminim/preader/makefile
 create mode 100644 extern/libpng/contrib/pngminim/preader/pngusr.dfa
 create mode 100644 extern/libpng/contrib/pngminim/preader/pngusr.h
 create mode 100644 extern/libpng/contrib/pngminus/CHANGES.txt
 create mode 100644 extern/libpng/contrib/pngminus/CMakeLists.txt
 create mode 100644 extern/libpng/contrib/pngminus/LICENSE.txt
 create mode 100644 extern/libpng/contrib/pngminus/Makefile
 create mode 100644 extern/libpng/contrib/pngminus/README.txt
 create mode 100644 extern/libpng/contrib/pngminus/makevms.com
 create mode 100755 extern/libpng/contrib/pngminus/png2pnm.bat
 create mode 100644 extern/libpng/contrib/pngminus/png2pnm.c
 create mode 100755 extern/libpng/contrib/pngminus/png2pnm.sh
 create mode 100755 extern/libpng/contrib/pngminus/pngminus.bat
 create mode 100755 extern/libpng/contrib/pngminus/pngminus.sh
 create mode 100755 extern/libpng/contrib/pngminus/pnm2png.bat
 create mode 100644 extern/libpng/contrib/pngminus/pnm2png.c
 create mode 100755 extern/libpng/contrib/pngminus/pnm2png.sh
 create mode 100644 extern/libpng/contrib/pngsuite/README
 create mode 100644 extern/libpng/contrib/pngsuite/bad_interlace_conversions.txt
 create mode 100644 extern/libpng/contrib/pngsuite/basn0g01.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn0g02.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn0g04.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn0g08.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn0g16.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn2c08.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn2c16.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn3p01.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn3p02.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn3p04.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn4a08.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn4a16.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn6a08.png
 create mode 100644 extern/libpng/contrib/pngsuite/basn6a16.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbbn0g01.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbbn0g02.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbbn0g04.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbbn2c16.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbbn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbgn2c16.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbgn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbrn2c08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbwn0g16.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbwn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftbyn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftp0n0g08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftp0n2c08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftp0n3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ftp1n3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ibasn0g08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ibasn0g16.png
 create mode 100644 extern/libpng/contrib/pngsuite/ibasn2c08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ibasn2c16.png
 create mode 100644 extern/libpng/contrib/pngsuite/ibasn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ibasn4a08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ibasn4a16.png
 create mode 100644 extern/libpng/contrib/pngsuite/ibasn6a08.png
 create mode 100644 extern/libpng/contrib/pngsuite/ibasn6a16.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftbbn2c16.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftbbn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftbgn2c16.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftbgn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftbrn2c08.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftbwn0g16.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftbwn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftbyn3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftp0n0g08.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftp0n2c08.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftp0n3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/iftp1n3p08.png
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/README
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/ibasn0g01.png
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/ibasn0g02.png
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/ibasn0g04.png
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/ibasn3p01.png
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/ibasn3p02.png
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/ibasn3p04.png
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/iftbbn0g01.png
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/iftbbn0g02.png
 create mode 100644 extern/libpng/contrib/pngsuite/interlaced/iftbbn0g04.png
 create mode 100644 extern/libpng/contrib/powerpc-vsx/README
 create mode 100644 extern/libpng/contrib/powerpc-vsx/linux.c
 create mode 100644 extern/libpng/contrib/powerpc-vsx/linux_aux.c
 create mode 100644 extern/libpng/contrib/testpngs/crashers/bad_iCCP.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/badadler.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/badcrc.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/empty_ancillary_chunks.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_IDAT.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_bKGD_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_cHRM_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_eXIf_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_gAMA_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_hIST_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_iCCP_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_iTXt_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_juNK_unsafe_to_copy.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_juNk_safe_to_copy.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_pCAL_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_pHYs_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_sCAL_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_sPLT_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_sRGB_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_sTER_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_tEXt_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_tIME_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/crashers/huge_zTXt_chunk.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-1-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-1-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-1-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-1-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-1-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-1-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-1-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-1.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-16-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-16-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-16-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-16-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-16-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-16-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-16-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-16.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-2-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-2-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-2-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-2-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-2-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-2-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-2-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-2.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-4-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-4-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-4-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-4-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-4-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-4-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-4-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-4.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-8-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-8-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-8-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-8-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-8-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-8-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-8.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-alpha-16-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-alpha-16-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-alpha-16-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-alpha-16.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-alpha-8-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-alpha-8-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-alpha-8-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/gray-alpha-8.png
 create mode 100755 extern/libpng/contrib/testpngs/makepngs.sh
 create mode 100644 extern/libpng/contrib/testpngs/palette-1-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-1-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-1-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-1-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-1-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-1-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-1-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-1.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-2-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-2-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-2-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-2-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-2-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-2-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-2-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-2.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-4-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-4-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-4-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-4-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-4-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-4-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-4-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-4.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-8-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-8-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-8-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-8-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-8-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-8-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/palette-8.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-16-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-16-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-16-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-16-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-16-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-16-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-16-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-16.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-8-1.8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-8-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-8-linear-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-8-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-8-sRGB-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-8-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-8-tRNS.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-8.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-alpha-16-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-alpha-16-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-alpha-16-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-alpha-16.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-alpha-8-1.8.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-alpha-8-linear.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-alpha-8-sRGB.png
 create mode 100644 extern/libpng/contrib/testpngs/rgb-alpha-8.png
 create mode 100644 extern/libpng/contrib/tools/README.txt
 create mode 100644 extern/libpng/contrib/tools/checksum-icc.c
 create mode 100755 extern/libpng/contrib/tools/chkfmt
 create mode 100644 extern/libpng/contrib/tools/cvtcolor.c
 create mode 100644 extern/libpng/contrib/tools/genpng.c
 create mode 100755 extern/libpng/contrib/tools/intgamma.sh
 create mode 100644 extern/libpng/contrib/tools/makesRGB.c
 create mode 100644 extern/libpng/contrib/tools/png-fix-itxt.c
 create mode 100644 extern/libpng/contrib/tools/pngcp.c
 create mode 100644 extern/libpng/contrib/tools/pngfix.c
 create mode 100755 extern/libpng/contrib/tools/reindent
 create mode 100644 extern/libpng/contrib/tools/sRGB.h
 create mode 100644 extern/libpng/contrib/visupng/PngFile.c
 create mode 100644 extern/libpng/contrib/visupng/PngFile.h
 create mode 100644 extern/libpng/contrib/visupng/README.txt
 create mode 100644 extern/libpng/contrib/visupng/VisualPng.c
 create mode 100644 extern/libpng/contrib/visupng/VisualPng.dsp
 create mode 100644 extern/libpng/contrib/visupng/VisualPng.dsw
 create mode 100644 extern/libpng/contrib/visupng/VisualPng.ico
 create mode 100644 extern/libpng/contrib/visupng/VisualPng.png
 create mode 100644 extern/libpng/contrib/visupng/VisualPng.rc
 create mode 100644 extern/libpng/contrib/visupng/cexcept.h
 create mode 100644 extern/libpng/contrib/visupng/resource.h
 create mode 100755 extern/libpng/depcomp
 create mode 100644 extern/libpng/example.c
 create mode 100755 extern/libpng/install-sh
 create mode 100644 extern/libpng/intel/filter_sse2_intrinsics.c
 create mode 100644 extern/libpng/intel/intel_init.c
 create mode 100644 extern/libpng/libpng-config.in
 create mode 100644 extern/libpng/libpng-manual.txt
 create mode 100644 extern/libpng/libpng.3
 create mode 100644 extern/libpng/libpng.pc.in
 create mode 100644 extern/libpng/libpngpf.3
 create mode 100755 extern/libpng/ltmain.sh
 create mode 100644 extern/libpng/mips/filter_msa_intrinsics.c
 create mode 100644 extern/libpng/mips/mips_init.c
 create mode 100755 extern/libpng/missing
 create mode 100644 extern/libpng/png.5
 create mode 100644 extern/libpng/png.c
 create mode 100644 extern/libpng/png.h
 create mode 100644 extern/libpng/pngbar.jpg
 create mode 100644 extern/libpng/pngbar.png
 create mode 100644 extern/libpng/pngconf.h
 create mode 100644 extern/libpng/pngdebug.h
 create mode 100644 extern/libpng/pngerror.c
 create mode 100644 extern/libpng/pngget.c
 create mode 100644 extern/libpng/pnginfo.h
 create mode 100644 extern/libpng/pngmem.c
 create mode 100644 extern/libpng/pngnow.png
 create mode 100644 extern/libpng/pngpread.c
 create mode 100644 extern/libpng/pngpriv.h
 create mode 100644 extern/libpng/pngread.c
 create mode 100644 extern/libpng/pngrio.c
 create mode 100644 extern/libpng/pngrtran.c
 create mode 100644 extern/libpng/pngrutil.c
 create mode 100644 extern/libpng/pngset.c
 create mode 100644 extern/libpng/pngstruct.h
 create mode 100644 extern/libpng/pngtest.c
 create mode 100644 extern/libpng/pngtest.png
 create mode 100644 extern/libpng/pngtrans.c
 create mode 100644 extern/libpng/pngusr.dfa
 create mode 100644 extern/libpng/pngwio.c
 create mode 100644 extern/libpng/pngwrite.c
 create mode 100644 extern/libpng/pngwtran.c
 create mode 100644 extern/libpng/pngwutil.c
 create mode 100644 extern/libpng/powerpc/filter_vsx_intrinsics.c
 create mode 100644 extern/libpng/powerpc/powerpc_init.c
 create mode 100644 extern/libpng/projects/owatcom/libpng.tgt
 create mode 100644 extern/libpng/projects/owatcom/libpng.wpj
 create mode 100644 extern/libpng/projects/owatcom/pngconfig.mak
 create mode 100644 extern/libpng/projects/owatcom/pngstest.tgt
 create mode 100644 extern/libpng/projects/owatcom/pngtest.tgt
 create mode 100644 extern/libpng/projects/owatcom/pngvalid.tgt
 create mode 100644 extern/libpng/projects/visualc71/PRJ0041.mak
 create mode 100644 extern/libpng/projects/visualc71/README.txt
 create mode 100644 extern/libpng/projects/visualc71/README_zlib.txt
 create mode 100644 extern/libpng/projects/visualc71/libpng.sln
 create mode 100644 extern/libpng/projects/visualc71/libpng.vcproj
 create mode 100644 extern/libpng/projects/visualc71/pngtest.vcproj
 create mode 100644 extern/libpng/projects/visualc71/zlib.vcproj
 create mode 100644 extern/libpng/projects/vstudio/README.txt
 create mode 100644 extern/libpng/projects/vstudio/libpng/libpng.vcxproj
 create mode 100644 extern/libpng/projects/vstudio/pnglibconf/pnglibconf.vcxproj
 create mode 100644 extern/libpng/projects/vstudio/pngstest/pngstest.vcxproj
 create mode 100644 extern/libpng/projects/vstudio/pngtest/pngtest.vcxproj
 create mode 100644 extern/libpng/projects/vstudio/pngunknown/pngunknown.vcxproj
 create mode 100644 extern/libpng/projects/vstudio/pngvalid/pngvalid.vcxproj
 create mode 100644 extern/libpng/projects/vstudio/vstudio.sln
 create mode 100644 extern/libpng/projects/vstudio/zlib.props
 create mode 100644 extern/libpng/projects/vstudio/zlib/zlib.vcxproj
 create mode 100644 extern/libpng/scripts/README.txt
 create mode 100644 extern/libpng/scripts/SCOPTIONS.ppc
 create mode 100755 extern/libpng/scripts/checksym.awk
 create mode 100644 extern/libpng/scripts/descrip.mms
 create mode 100755 extern/libpng/scripts/dfn.awk
 create mode 100644 extern/libpng/scripts/genchk.cmake.in
 create mode 100644 extern/libpng/scripts/genout.cmake.in
 create mode 100644 extern/libpng/scripts/gensrc.cmake.in
 create mode 100644 extern/libpng/scripts/intprefix.c
 create mode 100644 extern/libpng/scripts/libpng-config-body.in
 create mode 100644 extern/libpng/scripts/libpng-config-head.in
 create mode 100644 extern/libpng/scripts/libpng.pc.in
 create mode 100644 extern/libpng/scripts/libtool.m4
 create mode 100644 extern/libpng/scripts/ltoptions.m4
 create mode 100644 extern/libpng/scripts/ltsugar.m4
 create mode 100644 extern/libpng/scripts/ltversion.m4
 create mode 100644 extern/libpng/scripts/lt~obsolete.m4
 create mode 100644 extern/libpng/scripts/macro.lst
 create mode 100644 extern/libpng/scripts/makefile.32sunu
 create mode 100644 extern/libpng/scripts/makefile.64sunu
 create mode 100644 extern/libpng/scripts/makefile.acorn
 create mode 100644 extern/libpng/scripts/makefile.aix
 create mode 100644 extern/libpng/scripts/makefile.amiga
 create mode 100644 extern/libpng/scripts/makefile.atari
 create mode 100644 extern/libpng/scripts/makefile.bc32
 create mode 100644 extern/libpng/scripts/makefile.beos
 create mode 100644 extern/libpng/scripts/makefile.cegcc
 create mode 100644 extern/libpng/scripts/makefile.clang
 create mode 100644 extern/libpng/scripts/makefile.clang-asan
 create mode 100644 extern/libpng/scripts/makefile.darwin
 create mode 100644 extern/libpng/scripts/makefile.dec
 create mode 100644 extern/libpng/scripts/makefile.dj2
 create mode 100644 extern/libpng/scripts/makefile.freebsd
 create mode 100644 extern/libpng/scripts/makefile.gcc
 create mode 100644 extern/libpng/scripts/makefile.gcc-asan
 create mode 100644 extern/libpng/scripts/makefile.hp64
 create mode 100644 extern/libpng/scripts/makefile.hpgcc
 create mode 100644 extern/libpng/scripts/makefile.hpux
 create mode 100644 extern/libpng/scripts/makefile.ibmc
 create mode 100644 extern/libpng/scripts/makefile.intel
 create mode 100644 extern/libpng/scripts/makefile.linux
 create mode 100644 extern/libpng/scripts/makefile.linux-opt
 create mode 100644 extern/libpng/scripts/makefile.mips
 create mode 100644 extern/libpng/scripts/makefile.msys
 create mode 100644 extern/libpng/scripts/makefile.netbsd
 create mode 100644 extern/libpng/scripts/makefile.openbsd
 create mode 100644 extern/libpng/scripts/makefile.sco
 create mode 100644 extern/libpng/scripts/makefile.sggcc
 create mode 100644 extern/libpng/scripts/makefile.sgi
 create mode 100644 extern/libpng/scripts/makefile.so9
 create mode 100644 extern/libpng/scripts/makefile.solaris
 create mode 100644 extern/libpng/scripts/makefile.std
 create mode 100644 extern/libpng/scripts/makefile.sunos
 create mode 100644 extern/libpng/scripts/makefile.vcwin32
 create mode 100644 extern/libpng/scripts/makevms.com
 create mode 100755 extern/libpng/scripts/options.awk
 create mode 100644 extern/libpng/scripts/pnglibconf.dfa
 create mode 100644 extern/libpng/scripts/pnglibconf.h.prebuilt
 create mode 100755 extern/libpng/scripts/pnglibconf.mak
 create mode 100644 extern/libpng/scripts/pngwin.rc
 create mode 100644 extern/libpng/scripts/prefix.c
 create mode 100644 extern/libpng/scripts/smakefile.ppc
 create mode 100644 extern/libpng/scripts/sym.c
 create mode 100644 extern/libpng/scripts/symbols.c
 create mode 100644 extern/libpng/scripts/symbols.def
 create mode 100644 extern/libpng/scripts/test.cmake.in
 create mode 100644 extern/libpng/scripts/vers.c
 create mode 100755 extern/libpng/test-driver
 create mode 100755 extern/libpng/tests/pngimage-full
 create mode 100755 extern/libpng/tests/pngimage-quick
 create mode 100755 extern/libpng/tests/pngstest
 create mode 100755 extern/libpng/tests/pngstest-1.8
 create mode 100755 extern/libpng/tests/pngstest-1.8-alpha
 create mode 100755 extern/libpng/tests/pngstest-linear
 create mode 100755 extern/libpng/tests/pngstest-linear-alpha
 create mode 100755 extern/libpng/tests/pngstest-none
 create mode 100755 extern/libpng/tests/pngstest-none-alpha
 create mode 100755 extern/libpng/tests/pngstest-sRGB
 create mode 100755 extern/libpng/tests/pngstest-sRGB-alpha
 create mode 100755 extern/libpng/tests/pngtest
 create mode 100755 extern/libpng/tests/pngtest-badpngs
 create mode 100755 extern/libpng/tests/pngunknown-IDAT
 create mode 100755 extern/libpng/tests/pngunknown-discard
 create mode 100755 extern/libpng/tests/pngunknown-if-safe
 create mode 100755 extern/libpng/tests/pngunknown-sAPI
 create mode 100755 extern/libpng/tests/pngunknown-sTER
 create mode 100755 extern/libpng/tests/pngunknown-save
 create mode 100755 extern/libpng/tests/pngunknown-vpAg
 create mode 100755 extern/libpng/tests/pngvalid-gamma-16-to-8
 create mode 100755 extern/libpng/tests/pngvalid-gamma-alpha-mode
 create mode 100755 extern/libpng/tests/pngvalid-gamma-background
 create mode 100755 extern/libpng/tests/pngvalid-gamma-expand16-alpha-mode
 create mode 100755 extern/libpng/tests/pngvalid-gamma-expand16-background
 create mode 100755 extern/libpng/tests/pngvalid-gamma-expand16-transform
 create mode 100755 extern/libpng/tests/pngvalid-gamma-sbit
 create mode 100755 extern/libpng/tests/pngvalid-gamma-threshold
 create mode 100755 extern/libpng/tests/pngvalid-gamma-transform
 create mode 100755 extern/libpng/tests/pngvalid-progressive-interlace-standard
 create mode 100755 extern/libpng/tests/pngvalid-progressive-size
 create mode 100755 extern/libpng/tests/pngvalid-progressive-standard
 create mode 100755 extern/libpng/tests/pngvalid-standard
 create mode 100755 extern/libpng/tests/pngvalid-transform

diff --git a/.appveyor.yml b/.appveyor.yml
index e58109f1df..3d8861b350 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -24,8 +24,6 @@ init:
 
 install:
 - cmd: >-
-    git submodule update --init
-
     choco install cmake
 
     choco install nsis -version 2.46.0.20150406
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 930e3c4b17..6906bb2227 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,8 +8,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-        with:
-          submodules: true
       - name: Install dependencies
         run: sudo apt-get update && sudo apt-get install -y
           libasound2-dev
@@ -80,8 +78,6 @@ jobs:
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v2
-        with:
-          submodules: true
       - name: Install dependencies
         run: brew install
           nasm
@@ -95,8 +91,6 @@ jobs:
     runs-on: windows-latest
     steps:
       - uses: actions/checkout@v2
-        with:
-          submodules: true
       - name: Configure
         run: cmake -B build
       - name: Build
diff --git a/.gitmodules b/.gitmodules
index 19358079f0..e69de29bb2 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +0,0 @@
-[submodule "libpng"]
-	path = extern/libpng
-	url = https://git.code.sf.net/p/libpng/code
diff --git a/extern/libpng b/extern/libpng
deleted file mode 160000
index a40189cf88..0000000000
--- a/extern/libpng
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit a40189cf881e9f0db80511c382292a5604c3c3d1
diff --git a/extern/libpng/ANNOUNCE b/extern/libpng/ANNOUNCE
new file mode 100644
index 0000000000..ecf9c7043b
--- /dev/null
+++ b/extern/libpng/ANNOUNCE
@@ -0,0 +1,47 @@
+libpng 1.6.37 - April 14, 2019
+==============================
+
+This is a public release of libpng, intended for use in production code.
+
+
+Files available for download
+----------------------------
+
+Source files with LF line endings (for Unix/Linux):
+
+ * libpng-1.6.37.tar.xz (LZMA-compressed, recommended)
+ * libpng-1.6.37.tar.gz
+
+Source files with CRLF line endings (for Windows):
+
+ * lp1637.7z (LZMA-compressed, recommended)
+ * lp1637.zip
+
+Other information:
+
+ * README.md
+ * LICENSE.md
+ * AUTHORS.md
+ * TRADEMARK.md
+
+
+Changes since the previous public release (version 1.6.36)
+----------------------------------------------------------
+
+ * Fixed a use-after-free vulnerability (CVE-2019-7317) in png_image_free.
+ * Fixed a memory leak in the ARM NEON implementation of png_do_expand_palette.
+ * Fixed a memory leak in pngtest.c.
+ * Fixed two vulnerabilities (CVE-2018-14048, CVE-2018-14550) in
+   contrib/pngminus; refactor.
+ * Changed the license of contrib/pngminus to MIT; refresh makefile and docs.
+   (Contributed by Willem van Schaik)
+ * Fixed a typo in the libpng license v2.
+   (Contributed by Miguel Ojeda)
+ * Added makefiles for AddressSanitizer-enabled builds.
+ * Cleaned up various makefiles.
+
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net.
+Subscription is required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe.
diff --git a/extern/libpng/AUTHORS b/extern/libpng/AUTHORS
new file mode 100644
index 0000000000..79a3d10361
--- /dev/null
+++ b/extern/libpng/AUTHORS
@@ -0,0 +1,45 @@
+PNG REFERENCE LIBRARY AUTHORS
+=============================
+
+This is the list of PNG Reference Library ("libpng") Contributing
+Authors, for copyright and licensing purposes.
+
+ * Andreas Dilger
+ * Cosmin Truta
+ * Dave Martindale
+ * Eric S. Raymond
+ * Gilles Vollant
+ * Glenn Randers-Pehrson
+ * Greg Roelofs
+ * Guy Eric Schalnat
+ * James Yu
+ * John Bowler
+ * Kevin Bracey
+ * Magnus Holmgren
+ * Mandar Sahastrabuddhe
+ * Mans Rullgard
+ * Matt Sarett
+ * Mike Klein
+ * Paul Schmidt
+ * Sam Bushell
+ * Samuel Williams
+ * Simon-Pierre Cadieux
+ * Tim Wegner
+ * Tom Lane
+ * Tom Tanner
+ * Vadim Barkov
+ * Willem van Schaik
+ * Zhijie Liang
+ * Arm Holdings
+   - Richard Townsend
+ * Google Inc.
+   - Matt Sarett
+   - Mike Klein
+
+The build projects, the build scripts, the test scripts, and other
+files in the "projects", "scripts" and "tests" directories, have other
+copyright owners, but are released under the libpng license.
+
+Some files in the "contrib" directory, and some tools-generated files
+that are distributed with libpng, have other copyright owners, and are
+released under other open source licenses.
diff --git a/extern/libpng/CHANGES b/extern/libpng/CHANGES
new file mode 100644
index 0000000000..f0b0a9342c
--- /dev/null
+++ b/extern/libpng/CHANGES
@@ -0,0 +1,6109 @@
+CHANGES - changes for libpng
+
+version 0.1 [March 29, 1995]
+  initial work-in-progress release
+
+version 0.2 [April 1, 1995]
+  added reader into png.h
+  fixed small problems in stub file
+
+version 0.3 [April 8, 1995]
+  added pull reader
+  split up pngwrite.c to several files
+  added pnglib.txt
+  added example.c
+  cleaned up writer, adding a few new transformations
+  fixed some bugs in writer
+  interfaced with zlib 0.5
+  added K&R support
+  added check for 64 KB blocks for 16 bit machines
+
+version 0.4 [April 26, 1995]
+  cleaned up code and commented code
+  simplified time handling into png_time
+  created png_color_16 and png_color_8 to handle color needs
+  cleaned up color type defines
+  fixed various bugs
+  made various names more consistent
+  interfaced with zlib 0.71
+  cleaned up zTXt reader and writer (using zlib's Reset functions)
+  split transformations into pngrtran.c and pngwtran.c
+
+version 0.5 [April 30, 1995]
+  interfaced with zlib 0.8
+  fixed many reading and writing bugs
+  saved using 3 spaces instead of tabs
+
+version 0.6 [May 1, 1995]
+  first beta release
+  added png_large_malloc() and png_large_free()
+  added png_size_t
+  cleaned up some compiler warnings
+  added png_start_read_image()
+
+version 0.7 [June 24, 1995]
+  cleaned up lots of bugs
+  finished dithering and other stuff
+  added test program
+  changed name from pnglib to libpng
+
+version 0.71 [June 26, 1995]
+  changed pngtest.png for zlib 0.93
+  fixed error in libpng.txt and example.c
+
+version 0.8 [August 20, 1995]
+  cleaned up some bugs
+  added png_set_filler()
+  split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
+  added #define's to remove unwanted code
+  moved png_info_init() to png.c
+  added old_size into png_realloc()
+  added functions to manually set filtering and compression info
+  changed compression parameters based on image type
+  optimized filter selection code
+  added version info
+  changed external functions passing floats to doubles (k&r problems?)
+  put all the configurable stuff in pngconf.h
+  enabled png_set_shift to work with paletted images on read
+  added png_read_update_info() - updates info structure with transformations
+
+Version 0.81 [August, 1995]
+  incorporated Tim Wegner's medium model code (thanks, Tim)
+
+Version 0.82 [September, 1995]
+  [unspecified changes]
+
+Version 0.85 [December, 1995]
+  added more medium model code (almost everything's a far)
+  added i/o, error, and memory callback functions
+  fixed some bugs (16-bit, 4-bit interlaced, etc.)
+  added first run progressive reader (barely tested)
+
+Version 0.86 [January, 1996]
+  fixed bugs
+  improved documentation
+
+Version 0.87 [January, 1996]
+  fixed medium model bugs
+  fixed other bugs introduced in 0.85 and 0.86
+  added some minor documentation
+
+Version 0.88 [January, 1996]
+  fixed progressive bugs
+  replaced tabs with spaces
+  cleaned up documentation
+  added callbacks for read/write and warning/error functions
+
+Version 0.89 [June 5, 1996]
+  Added new initialization API to make libpng work better with shared libs
+    we now have png_create_read_struct(), png_create_write_struct(),
+    png_create_info_struct(), png_destroy_read_struct(), and
+    png_destroy_write_struct() instead of the separate calls to
+    malloc and png_read_init(), png_info_init(), and png_write_init()
+  Changed warning/error callback functions to fix bug - this means you
+    should use the new initialization API if you were using the old
+    png_set_message_fn() calls, and that the old API no longer exists
+    so that people are aware that they need to change their code
+  Changed filter selection API to allow selection of multiple filters
+    since it didn't work in previous versions of libpng anyways
+  Optimized filter selection code
+  Fixed png_set_background() to allow using an arbitrary RGB color for
+    paletted images
+  Fixed gamma and background correction for paletted images, so
+    png_correct_palette is not needed unless you are correcting an
+    external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
+    in pngconf.h) - if nobody uses this, it may disappear in the future.
+  Fixed bug with Borland 64K memory allocation (Alexander Lehmann)
+  Fixed bug in interlace handling (Smarasderagd, I think)
+  Added more error checking for writing and image to reduce invalid files
+  Separated read and write functions so that they won't both be linked
+    into a binary when only reading or writing functionality is used
+  New pngtest image also has interlacing and zTXt
+  Updated documentation to reflect new API
+
+Version 0.89c [June 17, 1996]
+  Bug fixes.
+
+Version 0.90 [January, 1997]
+  Made CRC errors/warnings on critical and ancillary chunks configurable
+  libpng will use the zlib CRC routines by (compile-time) default
+  Changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
+  Added external C++ wrapper statements to png.h (Gilles Dauphin)
+  Allow PNG file to be read when some or all of file signature has already
+    been read from the beginning of the stream.  ****This affects the size
+    of info_struct and invalidates all programs that use a shared libpng****
+  Fixed png_filler() declarations
+  Fixed? background color conversions
+  Fixed order of error function pointers to match documentation
+  Current chunk name is now available in png_struct to reduce the number
+    of nearly identical error messages (will simplify multi-lingual
+    support when available)
+  Try to get ready for unknown-chunk callback functions:
+    - previously read critical chunks are flagged, so the chunk handling
+      routines can determine if the chunk is in the right place
+    - all chunk handling routines have the same prototypes, so we will
+      be able to handle all chunks via a callback mechanism
+  Try to fix Linux "setjmp" buffer size problems
+  Removed png_large_malloc, png_large_free, and png_realloc functions.
+
+Version 0.95 [March, 1997]
+  Fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
+  Fixed bug in PNG file signature compares when start != 0
+  Changed parameter type of png_set_filler(...filler...) from png_byte
+    to png_uint_32
+  Added test for MACOS to ensure that both math.h and fp.h are not #included
+  Added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
+  Added "packswap" transformation, which changes the endianness of
+    packed-pixel bytes (Kevin Bracey)
+  Added "strip_alpha" transformation, which removes the alpha channel of
+    input images without using it (not necessarily a good idea)
+  Added "swap_alpha" transformation, which puts the alpha channel in front
+    of the color bytes instead of after
+  Removed all implicit variable tests which assume NULL == 0 (I think)
+  Changed several variables to "png_size_t" to show 16/32-bit limitations
+  Added new pCAL chunk read/write support
+  Added experimental filter selection weighting (Greg Roelofs)
+  Removed old png_set_rgbx() and png_set_xrgb() functions that have been
+    obsolete for about 2 years now (use png_set_filler() instead)
+  Added macros to read 16- and 32-bit ints directly from buffer, to be
+    used only on those systems that support it (namely PowerPC and 680x0)
+    With some testing, this may become the default for MACOS/PPC systems.
+  Only calculate CRC on data if we are going to use it
+  Added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
+  Added macros for simple libpng debugging output selectable at compile time
+  Removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
+  More description of info_struct in libpng.txt and png.h
+  More instructions in example.c
+  More chunk types tested in pngtest.c
+  Renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
+    png_set_<chunk>.  We now have corresponding png_get_<chunk>
+    functions in pngget.c to get information in info_ptr.  This isolates
+    the application from the internal organization of png_info_struct
+    (good for shared library implementations).
+
+Version 0.96 [May, 1997]
+  Fixed serious bug with < 8bpp images introduced in 0.95
+  Fixed 256-color transparency bug (Greg Roelofs)
+  Fixed up documentation (Greg Roelofs, Laszlo Nyul)
+  Fixed "error" in pngconf.h for Linux setjmp() behavior
+  Fixed DOS medium model support (Tim Wegner)
+  Fixed png_check_keyword() for case with error in static string text
+  Added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
+  Added typecasts to quiet compiler errors
+  Added more debugging info
+
+Version 0.97 [January, 1998]
+  Removed PNG_USE_OWN_CRC capability
+  Relocated png_set_crc_action from pngrutil.c to pngrtran.c
+  Fixed typecasts of "new_key", etc. (Andreas Dilger)
+  Added RFC 1152 [sic] date support
+  Fixed bug in gamma handling of 4-bit grayscale
+  Added 2-bit grayscale gamma handling (Glenn R-P)
+  Added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
+  Minor corrections in libpng.txt
+  Added simple sRGB support (Glenn R-P)
+  Easier conditional compiling, e.g.,
+    define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
+    all configurable options can be selected from command-line instead
+    of having to edit pngconf.h (Glenn R-P)
+  Fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
+  Added more conditions for png_do_background, to avoid changing
+    black pixels to background when a background is supplied and
+    no pixels are transparent
+  Repaired PNG_NO_STDIO behavior
+  Tested NODIV support and made it default behavior (Greg Roelofs)
+  Added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
+  Regularized version numbering scheme and bumped shared-library major
+    version number to 2 to avoid problems with libpng 0.89 apps
+    (Greg Roelofs)
+
+Version 0.98 [January, 1998]
+  Cleaned up some typos in libpng.txt and in code documentation
+  Fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
+  Cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
+  Changed recommendation about file_gamma for PC images to .51 from .45,
+    in example.c and libpng.txt, added comments to distinguish between
+    screen_gamma, viewing_gamma, and display_gamma.
+  Changed all references to RFC1152 to read RFC1123 and changed the
+    PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
+  Added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
+  Changed srgb_intent from png_byte to int to avoid compiler bugs
+
+Version 0.99 [January 30, 1998]
+  Free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
+  Fixed a longstanding "packswap" bug in pngtrans.c
+  Fixed some inconsistencies in pngconf.h that prevented compiling with
+    PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
+  Fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
+  Changed recommendation about file_gamma for PC images to .50 from .51 in
+    example.c and libpng.txt, and changed file_gamma for sRGB images to .45
+  Added a number of functions to access information from the png structure
+    png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
+  Added TARGET_MACOS similar to zlib-1.0.8
+  Define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
+  Added type casting to all png_malloc() function calls
+
+Version 0.99a [January 31, 1998]
+  Added type casts and parentheses to all returns that return a value.(Tim W.)
+
+Version 0.99b [February 4, 1998]
+  Added type cast png_uint_32 on malloc function calls where needed.
+  Changed type of num_hist from png_uint_32 to int (same as num_palette).
+  Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
+  Renamed makefile.elf to makefile.lnx.
+
+Version 0.99c [February 7, 1998]
+  More type casting.  Removed erroneous overflow test in pngmem.c.
+  Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
+  Added UNIX manual pages libpng.3 (incorporating libpng.txt) and  png.5.
+
+Version 0.99d [February 11, 1998]
+  Renamed "far_to_near()" "png_far_to_near()"
+  Revised libpng.3
+  Version 99c "buffered" operations didn't work as intended.  Replaced them
+    with png_memcpy_check() and png_memset_check().
+  Added many "if (png_ptr == NULL) return" to quell compiler warnings about
+    unused png_ptr, mostly in pngget.c and pngset.c.
+  Check for overlength tRNS chunk present when indexed-color PLTE is read.
+  Cleaned up spelling errors in libpng.3/libpng.txt
+  Corrected a problem with png_get_tRNS() which returned undefined trans array
+
+Version 0.99e [February 28, 1998]
+  Corrected png_get_tRNS() again.
+  Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
+  Touched up example.c to make more of it compileable, although the entire
+    file still can't be compiled (Willem van Schaik)
+  Fixed a bug in png_do_shift() (Bryan Tsai)
+  Added a space in png.h prototype for png_write_chunk_start()
+  Replaced pngtest.png with one created with zlib 1.1.1
+  Changed pngtest to report PASS even when file size is different (Jean-loup G.)
+  Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
+
+Version 0.99f [March 5, 1998]
+  Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
+  Moved makefiles into a "scripts" directory, and added INSTALL instruction file
+  Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
+  Added pointers to "note on libpng versions" in makefile.lnx and README
+  Added row callback feature when reading and writing nonprogressive rows
+    and added a test of this feature in pngtest.c
+  Added user transform callbacks, with test of the feature in pngtest.c
+
+Version 0.99g [March 6, 1998, morning]
+  Minor changes to pngtest.c to suppress compiler warnings.
+  Removed "beta" language from documentation.
+
+Version 0.99h [March 6, 1998, evening]
+  Minor changes to previous minor changes to pngtest.c
+  Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
+    and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
+  Added user transform capability
+
+Version 1.00 [March 7, 1998]
+  Changed several typedefs in pngrutil.c
+  Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
+  Replaced "while(1)" with "for(;;)"
+  Added PNGARG() to prototypes in pngtest.c and removed some prototypes
+  Updated some of the makefiles (Tom Lane)
+  Changed some typedefs (s_start, etc.) in pngrutil.c
+  Fixed dimensions of "short_months" array in pngwrite.c
+  Replaced ansi2knr.c with the one from jpeg-v6
+
+Version 1.0.0 [March 8, 1998]
+  Changed name from 1.00 to 1.0.0 (Adam Costello)
+  Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
+
+Version 1.0.0a [March 9, 1998]
+  Fixed three bugs in pngrtran.c to make gamma+background handling consistent
+    (Greg Roelofs)
+  Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
+    for major, minor, and bugfix releases.  This is 10001. (Adam Costello,
+    Tom Lane)
+  Make months range from 1-12 in png_convert_to_rfc1123
+
+Version 1.0.0b [March 13, 1998]
+  Quieted compiler complaints about two empty "for" loops in pngrutil.c
+  Minor changes to makefile.s2x
+  Removed #ifdef/#endif around a png_free() in pngread.c
+
+Version 1.0.1 [March 14, 1998]
+  Changed makefile.s2x to reduce security risk of using a relative pathname
+  Fixed some typos in the documentation (Greg).
+  Fixed a problem with value of "channels" returned by png_read_update_info()
+
+Version 1.0.1a [April 21, 1998]
+  Optimized Paeth calculations by replacing abs() function calls with intrinsics
+  plus other loop optimizations. Improves avg decoding speed by about 20%.
+  Commented out i386istic "align" compiler flags in makefile.lnx.
+  Reduced the default warning level in some makefiles, to make them consistent.
+  Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
+  Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
+  Added grayscale and 16-bit capability to png_do_read_filler().
+  Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
+    too large when writing an image with bit_depth < 8 (Bob Dellaca).
+  Corrected some bugs in the experimental weighted filtering heuristics.
+  Moved a misplaced pngrutil code block that truncates tRNS if it has more
+    than num_palette entries -- test was done before num_palette was defined.
+  Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
+  Changed compiler flags in makefile.wat for better optimization
+    (Pawel Mrochen).
+
+Version 1.0.1b [May 2, 1998]
+  Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
+  Relocated the png_composite macros from pngrtran.c to png.h (Greg).
+  Added makefile.sco (contributed by Mike Hopkirk).
+  Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
+  Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
+  More work on the Paeth-filtering, achieving imperceptible speedup
+    (A Kleinert).
+  More work on loop optimization which may help when compiled with C++
+    compilers.
+  Added warnings when people try to use transforms they've defined out.
+  Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
+  Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
+
+Version 1.0.1c [May 11, 1998]
+  Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
+    filler bytes should have been 0xff instead of 0xf.
+  Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
+  Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
+    out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
+  Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
+    for consistency, in pngconf.h
+  Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
+    to remove unwanted capabilities via the compile line
+  Made some corrections to grammar (which, it's) in documentation (Greg).
+  Corrected example.c, use of row_pointers in png_write_image().
+
+Version 1.0.1d [May 24, 1998]
+  Corrected several statements that used side effects illegally in pngrutil.c
+    and pngtrans.c, that were introduced in version 1.0.1b
+  Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
+  More corrections to example.c, use of row_pointers in png_write_image()
+    and png_read_rows().
+  Added pngdll.mak and pngdef.pas to scripts directory, contributed by
+    Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
+  Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
+  Changed several loops from count-down to count-up, for consistency.
+
+Version 1.0.1e [June 6, 1998]
+  Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
+    added warnings when people try to set png_read_fn and png_write_fn in
+    the same structure.
+  Added a test such that png_do_gamma will be done when num_trans==0
+    for truecolor images that have defined a background.  This corrects an
+    error that was introduced in libpng-0.90 that can cause gamma processing
+    to be skipped.
+  Added tests in png.h to include "trans" and "trans_values" in structures
+    when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
+  Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
+  Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
+  Added capability for user-provided malloc_fn() and free_fn() functions,
+    and revised pngtest.c to demonstrate their use, replacing the
+    PNGTEST_DEBUG_MEM feature.
+  Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
+
+Version 1.0.2 [June 14, 1998]
+  Fixed two bugs in makefile.bor .
+
+Version 1.0.2a [December 30, 1998]
+  Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
+  Fixed a bug in png_do_filler() that made it fail to write filler bytes in
+    the left-most pixel of each row (Kevin Bracey).
+  Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
+    in pngtest.c (Duncan Simpson).
+  Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
+    even when no tIME chunk was present in the source file.
+  Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
+  Fixed a problem in png_read_push_finish_row(), which would not skip some
+    passes that it should skip, for images that are less than 3 pixels high.
+  Interchanged the order of calls to png_do_swap() and png_do_shift()
+    in pngwtran.c (John Cromer).
+  Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
+  Changed "bad adaptive filter type" from error to warning in pngrutil.c .
+  Fixed a documentation error about default filtering with 8-bit indexed-color.
+  Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
+    (L. Peter Deutsch).
+  Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
+  Added png_get_copyright() and png_get_header_version() functions.
+  Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
+  Added information about debugging in libpng.txt and libpng.3 .
+  Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and
+    makefile.sco.
+  Removed lines after Dynamic Dependencies" in makefile.aco .
+  Revised makefile.dec to make a shared library (Jeremie Petit).
+  Removed trailing blanks from all files.
+
+Version 1.0.2a [January 6, 1999]
+  Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
+  Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
+  Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
+  Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
+    which is obsolete.
+
+Version 1.0.3 [January 14, 1999]
+  Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
+  Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
+
+Version 1.0.3a [August 12, 1999]
+  Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
+    if an attempt is made to read an interlaced image when it's not supported.
+  Added check if png_ptr->trans is defined before freeing it in pngread.c
+  Modified the Y2K statement to include versions back to version 0.71
+  Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
+  Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
+  Replaced leading blanks with tab characters in makefile.hux
+  Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
+  Changed (float)red and (float)green to (double)red, (double)green
+    in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
+  Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
+  Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
+  Updated documentation to refer to the PNG-1.2 specification.
+  Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
+    in makefile.knr, INSTALL, and README (L. Peter Deutsch)
+  Fixed bugs in calculation of the length of rowbytes when adding alpha
+    channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
+  Added function png_set_user_transform_info() to store user_transform_ptr,
+    user_depth, and user_channels into the png_struct, and a function
+    png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
+  Added function png_set_empty_plte_permitted() to make libpng useable
+    in MNG applications.
+  Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
+  Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
+    consistent with PNG-1.2, and allow variance of 500 before complaining.
+  Added assembler code contributed by Intel in file pngvcrd.c and modified
+    makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation,
+    Gilles Vollant)
+  Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
+  Added some aliases for png_set_expand() in pngrtran.c, namely
+    png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
+    (Greg Roelofs, in "PNG: The Definitive Guide").
+  Added makefile.beo for BEOS on X86, contributed by Sander Stok.
+
+Version 1.0.3b [August 26, 1999]
+  Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
+  Changed leading blanks to tabs in all makefiles.
+  Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
+  Made alternate versions of  png_set_expand() in pngrtran.c, namely
+    png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
+    (Greg Roelofs, in "PNG: The Definitive Guide").  Deleted the 1.0.3a aliases.
+  Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
+  Revised calculation of num_blocks in pngmem.c to avoid a potentially
+    negative shift distance, whose results are undefined in the C language.
+  Added a check in pngset.c to prevent writing multiple tIME chunks.
+  Added a check in pngwrite.c to detect invalid small window_bits sizes.
+
+Version 1.0.3d [September 4, 1999]
+  Fixed type casting of igamma in pngrutil.c
+  Added new png_expand functions to scripts/pngdef.pas and pngos2.def
+  Added a demo read_user_transform_fn that examines the row filters in pngtest.c
+
+Version 1.0.4 [September 24, 1999, not distributed publicly]
+  Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
+  Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
+  Made several minor corrections to pngtest.c
+  Renamed the makefiles with longer but more user friendly extensions.
+  Copied the PNG copyright and license to a separate LICENSE file.
+  Revised documentation, png.h, and example.c to remove reference to
+    "viewing_gamma" which no longer appears in the PNG specification.
+  Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
+  Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
+  Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
+    assembler code) and makefile.vcwin32 (doesn't).
+  Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
+  Added a copy of pngnow.png to the distribution.
+
+Version 1.0.4a [September 25, 1999]
+  Increase max_pixel_depth in pngrutil.c if a user transform needs it.
+  Changed several division operations to right-shifts in pngvcrd.c
+
+Version 1.0.4b [September 30, 1999]
+  Added parentheses in line 3732 of pngvcrd.c
+  Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
+
+Version 1.0.4c [October 1, 1999]
+  Added a "png_check_version" function in png.c and pngtest.c that will generate
+    a helpful compiler error if an old png.h is found in the search path.
+  Changed type of png_user_transform_depth|channels from int to png_byte.
+  Added "Libpng is OSI Certified Open Source Software" statement to png.h
+
+Version 1.0.4d [October 6, 1999]
+  Changed 0.45 to 0.45455 in png_set_sRGB()
+  Removed unused PLTE entries from pngnow.png
+  Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
+
+Version 1.0.4e [October 10, 1999]
+  Fixed sign error in pngvcrd.c (Greg Roelofs)
+  Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
+
+Version 1.0.4f [October 15, 1999]
+  Surrounded example.c code with #if 0 .. #endif to prevent people from
+    inadvertently trying to compile it.
+  Changed png_get_header_version() from a function to a macro in png.h
+  Added type casting mostly in pngrtran.c and pngwtran.c
+  Removed some pointless "ptr = NULL" in pngmem.c
+  Added a "contrib" directory containing the source code from Greg's book.
+
+Version 1.0.5 [October 15, 1999]
+  Minor editing of the INSTALL and README files.
+
+Version 1.0.5a [October 23, 1999]
+  Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
+  Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
+  Further optimization and bugfix of pngvcrd.c
+  Revised pngset.c so that it does not allocate or free memory in the user's
+    text_ptr structure.  Instead, it makes its own copy.
+  Created separate write_end_info_struct in pngtest.c for a more severe test.
+  Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
+
+Version 1.0.5b [November 23, 1999]
+  Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
+    PNG_FLAG_WROTE_tIME from flags to mode.
+  Added png_write_info_before_PLTE() function.
+  Fixed some typecasting in contrib/gregbook/*.c
+  Updated scripts/makevms.com and added makevms.com to contrib/gregbook
+    and contrib/pngminus (Martin Zinser)
+
+Version 1.0.5c [November 26, 1999]
+  Moved png_get_header_version from png.h to png.c, to accommodate ansi2knr.
+  Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
+    accommodate making DLL's: Moved usr_png_ver from global variable to function
+    png_get_header_ver() in png.c.  Moved png_sig to png_sig_bytes in png.c and
+    eliminated use of png_sig in pngwutil.c.  Moved the various png_CHNK arrays
+    into pngtypes.h.  Eliminated use of global png_pass arrays.  Declared the
+    png_CHNK and png_pass arrays to be "const".  Made the global arrays
+    available to applications (although none are used in libpng itself) when
+    PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
+  Removed some extraneous "-I" from contrib/pngminus/makefile.std
+  Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
+  Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
+
+Version 1.0.5d [November 29, 1999]
+  Add type cast (png_const_charp) two places in png.c
+  Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
+  Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
+    to applications a macro "PNG_USE_LOCAL_ARRAYS".
+  comment out (with #ifdef) all the new declarations when
+    PNG_USE_GLOBAL_ARRAYS is defined.
+  Added PNG_EXPORT_VAR macro to accommodate making DLL's.
+
+Version 1.0.5e [November 30, 1999]
+  Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
+    structure; refactored the inflate/deflate support to make adding new chunks
+    with trailing compressed parts easier in the future, and added new functions
+    png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
+    png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
+    NOTE: Applications that write text chunks MUST define png_text->lang
+    before calling png_set_text(). It must be set to NULL if you want to
+    write tEXt or zTXt chunks.  If you want your application to be able to
+    run with older versions of libpng, use
+
+      #ifdef PNG_iTXt_SUPPORTED
+         png_text[i].lang = NULL;
+      #endif
+
+  Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
+    offsets (Eric S. Raymond).
+  Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
+    PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
+    macros, leaving the separate macros also available.
+  Removed comments on #endifs at the end of many short, non-nested #if-blocks.
+
+Version 1.0.5f [December 6, 1999]
+  Changed makefile.solaris to issue a warning about potential problems when
+    the ucb "ld" is in the path ahead of the ccs "ld".
+  Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
+  Added sCAL chunk support (Eric S. Raymond).
+
+Version 1.0.5g [December 7, 1999]
+  Fixed "png_free_spallettes" typo in png.h
+  Added code to handle new chunks in pngpread.c
+  Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
+  Added "translated_key" to png_text structure and png_write_iTXt().
+  Added code in pngwrite.c to work around a newly discovered zlib bug.
+
+Version 1.0.5h [December 10, 1999]
+  NOTE: regarding the note for version 1.0.5e, the following must also
+    be included in your code:
+        png_text[i].translated_key = NULL;
+  Unknown chunk handling is now supported.
+  Option to eliminate all floating point support was added.  Some new
+    fixed-point functions such as png_set_gAMA_fixed() were added.
+  Expanded tabs and removed trailing blanks in source files.
+
+Version 1.0.5i [December 13, 1999]
+  Added some type casts to silence compiler warnings.
+  Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
+  Removed leading blanks from a #define in pngvcrd.c
+  Added some parameters to the new png_set_keep_unknown_chunks() function.
+  Added a test for up->location != 0 in the first instance of writing
+    unknown chunks in pngwrite.c
+  Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
+    prevent recursion.
+  Added png_free_hIST() function.
+  Various patches to fix bugs in the sCAL and integer cHRM processing,
+    and to add some convenience macros for use with sCAL.
+
+Version 1.0.5j [December 21, 1999]
+  Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
+    around buggy compilers.
+  Added new type "png_fixed_point" for integers that hold float*100000 values
+  Restored backward compatibility of tEXt/zTXt chunk processing:
+    Restored the first four members of png_text to the same order as v.1.0.5d.
+    Added members "lang_key" and "itxt_length" to png_text struct.  Set
+    text_length=0 when "text" contains iTXt data.  Use the "compression"
+    member to distinguish among tEXt/zTXt/iTXt types.  Added
+    PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
+    The "Note" above, about backward incompatibility of libpng-1.0.5e, no
+    longer applies.
+  Fixed png_read|write_iTXt() to read|write parameters in the right order,
+    and to write the iTXt chunk after IDAT if it appears in the end_ptr.
+  Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
+  Reversed the order of trying to write floating-point and fixed-point gAMA.
+
+Version 1.0.5k [December 27, 1999]
+  Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
+  Added png_handle_as_unknown() function (Glenn)
+  Added png_free_chunk_list() function and chunk_list and num_chunk_list members
+    of png_ptr.
+  Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
+  Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
+    about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
+  Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
+  Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
+  Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
+
+Version 1.0.5l [January 1, 2000]
+  Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
+    for setting a callback function to handle unknown chunks and for
+    retrieving the associated user pointer (Glenn).
+
+Version 1.0.5m [January 7, 2000]
+  Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
+
+Version 1.0.5n [January 9, 2000]
+  Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
+    own memory for info_ptr->palette.  This makes it safe for the calling
+    application to free its copy of the palette any time after it calls
+    png_set_PLTE().
+
+Version 1.0.5o [January 20, 2000]
+  Cosmetic changes only (removed some trailing blanks and TABs)
+
+Version 1.0.5p [January 31, 2000]
+  Renamed pngdll.mak to makefile.bd32
+  Cosmetic changes in pngtest.c
+
+Version 1.0.5q [February 5, 2000]
+  Relocated the makefile.solaris warning about PATH problems.
+  Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
+  Revised makefile.gcmmx
+  Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
+
+Version 1.0.5r [February 7, 2000]
+  Removed superfluous prototype for png_get_itxt from png.h
+  Fixed a bug in pngrtran.c that improperly expanded the background color.
+  Return *num_text=0 from png_get_text() when appropriate, and fix documentation
+    of png_get_text() in libpng.txt/libpng.3.
+
+Version 1.0.5s [February 18, 2000]
+  Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
+    new error handler that's planned for the next libpng release, and changed
+    example.c, pngtest.c, and contrib programs to use this macro.
+  Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
+  Fixed a bug in png_read_png() that caused it to fail to expand some images
+    that it should have expanded.
+  Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
+    in pngget.c
+  Changed the allocation of palette, history, and trans arrays back to
+    the version 1.0.5 method (linking instead of copying) which restores
+    backward compatibility with version 1.0.5.  Added some remarks about
+    that in example.c.  Added "free_me" member to info_ptr and png_ptr
+    and added png_free_data() function.
+  Updated makefile.linux and makefile.gccmmx to make directories conditionally.
+  Made cosmetic changes to pngasmrd.h
+  Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
+  Modified png_read_png() to allocate info_ptr->row_pointers only if it
+    hasn't already been allocated.
+
+Version 1.0.5t [March 4, 2000]
+  Changed png_jmp_env() migration aiding macro to png_jmpbuf().
+  Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
+  Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
+    PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
+  Files in contrib/gregbook were revised to use png_jmpbuf() and to select
+    a 24-bit visual if one is available, and to allow abbreviated options.
+  Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
+  Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
+
+Version 1.0.5u [March 5, 2000]
+  Simplified the code that detects old png.h in png.c and pngtest.c
+  Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
+  Increased precision of rgb_to_gray calculations from 8 to 15 bits and
+    added png_set_rgb_to_gray_fixed() function.
+  Added makefile.bc32 (32-bit Borland C++, C mode)
+
+Version 1.0.5v [March 11, 2000]
+  Added some parentheses to the png_jmpbuf macro definition.
+  Updated references to the zlib home page, which has moved to freesoftware.com.
+  Corrected bugs in documentation regarding png_read_row() and png_write_row().
+  Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
+  Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
+    revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
+
+Version 1.0.6 [March 20, 2000]
+  Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
+  Added makefile.sggcc (SGI IRIX with gcc)
+
+Version 1.0.6d [April 7, 2000]
+  Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
+  Added data_length parameter to png_decompress_chunk() function
+  Revised documentation to remove reference to abandoned png_free_chnk functions
+  Fixed an error in png_rgb_to_gray_fixed()
+  Revised example.c, usage of png_destroy_write_struct().
+  Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
+  Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c
+  Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
+
+Version 1.0.6e [April 9, 2000]
+  Added png_data_freer() function.
+  In the code that checks for over-length tRNS chunks, added check of
+    info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
+  Minor revisions of libpng.txt/libpng.3.
+  Check for existing data and free it if the free_me flag is set, in png_set_*()
+    and png_handle_*().
+  Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
+    is defined.
+  Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
+    and mentioned the purposes of the two macros in libpng.txt/libpng.3.
+
+Version 1.0.6f [April 14, 2000]
+  Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
+  Add checks in png_set_text() for NULL members of the input text structure.
+  Revised libpng.txt/libpng.3.
+  Removed superfluous prototype for png_set_iTXt from png.h
+  Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
+  Changed several png_errors about malformed ancillary chunks to png_warnings.
+
+Version 1.0.6g [April 24, 2000]
+  Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
+  Relocated paragraph about png_set_background() in libpng.3/libpng.txt
+    and other revisions (Matthias Benckmann)
+  Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
+    png_ptr members to restore binary compatibility with libpng-1.0.5
+    (breaks compatibility with libpng-1.0.6).
+
+Version 1.0.6h [April 24, 2000]
+  Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
+    libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
+    This is a temporary change for test purposes.
+
+Version 1.0.6i [May 2, 2000]
+  Rearranged some members at the end of png_info and png_struct, to put
+    unknown_chunks_num and free_me within the original size of the png_structs
+    and free_me, png_read_user_fn, and png_free_fn within the original png_info,
+    because some old applications allocate the structs directly instead of
+    using png_create_*().
+  Added documentation of user memory functions in libpng.txt/libpng.3
+  Modified png_read_png so that it will use user_allocated row_pointers
+    if present, unless free_me directs that it be freed, and added description
+    of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
+  Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
+    1.00) members of png_struct and png_info, to regain binary compatibility
+    when you define this macro.  Capabilities lost in this event
+    are user transforms (new in version 1.0.0),the user transform pointer
+    (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
+    the high-level interface, and unknown chunks support (all new in 1.0.6).
+    This was necessary because of old applications that allocate the structs
+    directly as authors were instructed to do in libpng-0.88 and earlier,
+    instead of using png_create_*().
+  Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
+    can be used to detect codes that directly allocate the structs, and
+    code to check these modes in png_read_init() and png_write_init() and
+    generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
+    was not defined.
+  Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
+
+Version 1.0.6j [May 3, 2000]
+  Overloaded png_read_init() and png_write_init() with macros that convert
+    calls to png_read_init_2() or png_write_init_2() that check the version
+    and structure sizes.
+
+Version 1.0.7beta11 [May 7, 2000]
+  Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
+    which are no longer used.
+  Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
+    defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXt_SUPPORTED
+    is defined.
+  Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
+    overrun when old applications fill the info_ptr->text structure directly.
+  Added PNGAPI macro, and added it to the definitions of all exported functions.
+  Relocated version macro definitions ahead of the includes of zlib.h and
+    pngconf.h in png.h.
+
+Version 1.0.7beta12 [May 12, 2000]
+  Revised pngset.c to avoid a problem with expanding the png_debug macro.
+  Deleted some extraneous defines from pngconf.h
+  Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
+  Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
+  Added png_access_version_number() function.
+  Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
+  Expanded libpng.3/libpng.txt information about png_data_freer().
+
+Version 1.0.7beta14 [May 17, 2000] (beta13 was not published)
+  Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as
+    warnings instead of errors, as pngrutil.c does.
+  Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png()
+    will actually write IDATs.
+  Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32.
+  Make png_free_data() ignore its final parameter except when freeing data
+    that can have multiple instances (text, sPLT, unknowns).
+  Fixed a new bug in png_set_rows().
+  Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5.
+  Added png_set_invalid() function.
+  Fixed incorrect illustrations of png_destroy_write_struct() in example.c.
+
+Version 1.0.7beta15 [May 30, 2000]
+  Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce
+    fewer error messages.
+  Rearranged checks for Z_OK to check the most likely path first in pngpread.c
+    and pngwutil.c.
+  Added checks in pngtest.c for png_create_*() returning NULL, and mentioned
+    in libpng.txt/libpng.3 the need for applications to check this.
+  Changed names of png_default_*() functions in pngtest to pngtest_*().
+  Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32.
+  Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c
+  Set each pointer to NULL after freeing it in png_free_data().
+  Worked around a problem in pngconf.h; AIX's strings.h defines an "index"
+    macro that conflicts with libpng's png_color_16.index. (Dimitri
+    Papadapoulos)
+  Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux).
+
+Version 1.0.7beta16 [June 4, 2000]
+  Revised the workaround of AIX string.h "index" bug.
+  Added a check for overlength PLTE chunk in pngrutil.c.
+  Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer
+    indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler.
+  Added a warning in png_decompress_chunk() when it runs out of data, e.g.
+    when it tries to read an erroneous PhotoShop iCCP chunk.
+  Added PNG_USE_DLL macro.
+  Revised the copyright/disclaimer/license notice.
+  Added contrib/msvctest directory
+
+Version 1.0.7rc1 [June 9, 2000]
+  Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA  (0x0400 not 0x0200)
+  Added contrib/visupng directory (Willem van Schaik)
+
+Version 1.0.7beta18 [June 23, 2000]
+  Revised PNGAPI definition, and pngvcrd.c to work with __GCC__
+    and do not redefine PNGAPI if it is passed in via a compiler directive.
+  Revised visupng/PngFile.c to remove returns from within the Try block.
+  Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros.
+  Updated contrib/visupng/cexcept.h to version 1.0.0.
+  Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks.
+
+Version 1.0.7rc2 [June 28, 2000]
+  Updated license to include disclaimers required by UCITA.
+  Fixed "DJBPP" typo in pnggccrd.c introduced in beta18.
+
+Version 1.0.7 [July 1, 2000]
+  Revised the definition of "trans_values" in libpng.3/libpng.txt
+
+Version 1.0.8beta1 [July 8, 2000]
+  Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
+  Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
+    pngwutil.c.
+  Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
+  Removed unused "#include <assert.h>" from png.c
+  Added WindowsCE support.
+  Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment.
+
+Version 1.0.8beta2 [July 10, 2000]
+  Added project files to the wince directory and made further revisions
+    of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
+
+Version 1.0.8beta3 [July 11, 2000]
+  Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
+    for indexed-color input files to avoid potential double-freeing trans array
+    under some unusual conditions; problem was introduced in version 1.0.6f.
+  Further revisions to pngtest.c and files in the wince subdirectory.
+
+Version 1.0.8beta4 [July 14, 2000]
+  Added the files pngbar.png and pngbar.jpg to the distribution.
+  Added makefile.cygwin, and cygwin support in pngconf.h
+  Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory)
+
+Version 1.0.8rc1 [July 16, 2000]
+  Revised png_debug() macros and statements to eliminate compiler warnings.
+
+Version 1.0.8 [July 24, 2000]
+  Added png_flush() in pngwrite.c, after png_write_IEND().
+  Updated makefile.hpux to build a shared library.
+
+Version 1.0.9beta1 [November 10, 2000]
+  Fixed typo in scripts/makefile.hpux
+  Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
+  Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
+  Changed "cdrom.com" in documentation to "libpng.org"
+  Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
+  Changed type of "params" from voidp to png_voidp in png_read|write_png().
+  Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h.
+  Revised the 3 instances of WRITEFILE in pngtest.c.
+  Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory.
+  Updated png.rc in dll/msvc project
+  Revised makefile.dec to define and use LIBPATH and INCPATH
+  Increased size of global png_libpng_ver[] array from 12 to 18 chars.
+  Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const.
+  Removed duplicate png_crc_finish() from png_handle_bKGD() function.
+  Added a warning when application calls png_read_update_info() multiple times.
+  Revised makefile.cygwin
+  Fixed bugs in iCCP support in pngrutil.c and pngwutil.c.
+  Replaced png_set_empty_plte_permitted() with png_permit_mng_features().
+
+Version 1.0.9beta2 [November 19, 2000]
+  Renamed the "dll" subdirectory "projects".
+  Added borland project files to "projects" subdirectory.
+  Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate.
+  Add error message in png_set_compression_buffer_size() when malloc fails.
+
+Version 1.0.9beta3 [November 23, 2000]
+  Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project.
+  Removed the png_flush() in pngwrite.c that crashes some applications
+    that don't set png_output_flush_fn.
+  Added makefile.macosx and makefile.aix to scripts directory.
+
+Version 1.0.9beta4 [December 1, 2000]
+  Change png_chunk_warning to png_warning in png_check_keyword().
+  Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
+
+Version 1.0.9beta5 [December 15, 2000]
+  Added support for filter method 64 (for PNG datastreams embedded in MNG).
+
+Version 1.0.9beta6 [December 18, 2000]
+  Revised png_set_filter() to accept filter method 64 when appropriate.
+  Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
+    help prevent applications from using MNG features in PNG datastreams.
+  Added png_permit_mng_features() function.
+  Revised libpng.3/libpng.txt.  Changed "filter type" to "filter method".
+
+Version 1.0.9rc1 [December 23, 2000]
+  Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c
+  Fixed error handling of unknown compression type in png_decompress_chunk().
+  In pngconf.h, define __cdecl when _MSC_VER is defined.
+
+Version 1.0.9beta7 [December 28, 2000]
+  Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places.
+  Revised memory management in png_set_hIST and png_handle_hIST in a backward
+    compatible manner.  PLTE and tRNS were revised similarly.
+  Revised the iCCP chunk reader to ignore trailing garbage.
+
+Version 1.0.9beta8 [January 12, 2001]
+  Moved pngasmrd.h into pngconf.h.
+  Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop.
+
+Version 1.0.9beta9 [January 15, 2001]
+  Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to
+    wince and msvc project module definition files.
+  Minor revision of makefile.cygwin.
+  Fixed bug with progressive reading of narrow interlaced images in pngpread.c
+
+Version 1.0.9beta10 [January 16, 2001]
+  Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined.
+  Fixed "png_mmx_supported" typo in project definition files.
+
+Version 1.0.9beta11 [January 19, 2001]
+  Updated makefile.sgi to make shared library.
+  Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED
+    by default, for the benefit of DLL forward compatibility.  These will
+    be re-enabled in version 1.2.0.
+
+Version 1.0.9rc2 [January 22, 2001]
+  Revised cygwin support.
+
+Version 1.0.9 [January 31, 2001]
+  Added check of cygwin's ALL_STATIC in pngconf.h
+  Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
+
+Version 1.0.10beta1 [March 14, 2001]
+  Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
+  Reformatted libpng.3 to eliminate bad line breaks.
+  Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
+  Added prototype for png_mmx_support() near the top of pnggccrd.c
+  Moved some error checking from png_handle_IHDR to png_set_IHDR.
+  Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
+  Revised png_mmx_support() function in pnggccrd.c
+  Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
+  Fixed memory leak in contrib/visupng/PngFile.c
+  Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
+  Added warnings when retrieving or setting gamma=0.
+  Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
+
+Version 1.0.10rc1 [March 23, 2001]
+  Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
+    and png_strlen.
+  Revised png_mmx_supported() function in pnggccrd.c to return proper value.
+  Fixed bug in progressive reading (pngpread.c) with small images (height < 8).
+
+Version 1.0.10 [March 30, 2001]
+  Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
+  Added beos project files (Chris Herborth)
+
+Version 1.0.11beta1 [April 3, 2001]
+  Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
+  Removed a no-longer needed AIX work-around from pngconf.h
+  Changed several "//" single-line comments to C-style in pnggccrd.c
+
+Version 1.0.11beta2 [April 11, 2001]
+  Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
+  Updated scripts/pngos2.def
+
+Version 1.0.11beta3 [April 14, 2001]
+  Added checking the results of many instances of png_malloc() for NULL
+
+Version 1.0.11beta4 [April 20, 2001]
+  Undid the changes from version 1.0.11beta3.  Added a check for NULL return
+    from user's malloc_fn().
+  Removed some useless type casts of the NULL pointer.
+  Added makefile.netbsd
+
+Version 1.0.11 [April 27, 2001]
+  Revised makefile.netbsd
+
+Version 1.0.12beta1 [May 14, 2001]
+  Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
+  Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
+  Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
+  Eliminated the png_error about apps using png_read|write_init().  Instead,
+    libpng will reallocate the png_struct and info_struct if they are too small.
+    This retains future binary compatibility for old applications written for
+    libpng-0.88 and earlier.
+
+Version 1.2.0beta1 [May 6, 2001]
+  Bumped DLLNUM to 2.
+  Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED
+    by default.
+  Added runtime selection of MMX features.
+  Added png_set_strip_error_numbers function and related macros.
+
+Version 1.2.0beta2 [May 7, 2001]
+  Finished merging 1.2.0beta1 with version 1.0.11
+  Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
+
+Version 1.2.0beta3 [May 17, 2001]
+  Enabled user memory function by default.
+  Modified png_create_struct so it passes user mem_ptr to user memory allocator.
+  Increased png_mng_features flag from png_byte to png_uint_32.
+  Bumped shared-library (so-number) and dll-number to 3.
+
+Version 1.2.0beta4 [June 23, 2001]
+  Check for missing profile length field in iCCP chunk and free chunk_data
+    in case of truncated iCCP chunk.
+  Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
+  Bumped dll-number from 2 to 3 in makefile.cygwin
+  Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
+    if user attempts to run it on an 8-bit display.
+  Updated contrib/gregbook
+  Use png_malloc instead of png_zalloc to allocate palette in pngset.c
+  Updated makefile.ibmc
+  Added some typecasts to eliminate gcc 3.0 warnings.  Changed prototypes
+    of png_write_oFFS width and height from png_uint_32 to png_int_32.
+  Updated example.c
+  Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
+
+Version 1.2.0beta5 [August 8, 2001]
+  Revised contrib/gregbook
+  Revised makefile.gcmmx
+  Revised pnggccrd.c to conditionally compile some thread-unsafe code only
+    when PNG_THREAD_UNSAFE_OK is defined.
+  Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
+    value exceeding 2^bit_depth-1
+  Revised makefile.sgi and makefile.sggcc
+  Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
+  Removed restriction that do_invert_mono only operate on 1-bit opaque files
+
+Version 1.2.0 [September 1, 2001]
+  Changed a png_warning() to png_debug() in pnggccrd.c
+  Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC().
+
+Version 1.2.1beta1 [October 19, 2001]
+  Revised makefile.std in contrib/pngminus
+  Include background_1 in png_struct regardless of gamma support.
+  Revised makefile.netbsd and makefile.macosx, added makefile.darwin.
+  Revised example.c to provide more details about using row_callback().
+
+Version 1.2.1beta2 [October 25, 2001]
+  Added type cast to each NULL appearing in a function call, except for
+    WINCE functions.
+  Added makefile.so9.
+
+Version 1.2.1beta3 [October 27, 2001]
+  Removed type casts from all NULLs.
+  Simplified png_create_struct_2().
+
+Version 1.2.1beta4 [November 7, 2001]
+  Revised png_create_info_struct() and png_creat_struct_2().
+  Added error message if png_write_info() was omitted.
+  Type cast NULLs appearing in function calls when _NO_PROTO or
+    PNG_TYPECAST_NULL is defined.
+
+Version 1.2.1rc1 [November 24, 2001]
+  Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL
+    is defined.
+  Changed typecast of "size" argument to png_size_t in pngmem.c calls to
+    the user malloc_fn, to agree with the prototype in png.h
+  Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev)
+  Updated makefile.sgi to recognize LIBPATH and INCPATH.
+  Updated various makefiles so "make clean" does not remove previous major
+    version of the shared library.
+
+Version 1.2.1rc2 [December 4, 2001]
+  Always allocate 256-entry internal palette, hist, and trans arrays, to
+    avoid out-of-bounds memory reference caused by invalid PNG datastreams.
+  Added a check for prefix_length > data_length in iCCP chunk handler.
+
+Version 1.2.1 [December 7, 2001]
+  None.
+
+Version 1.2.2beta1 [February 22, 2002]
+  Fixed a bug with reading the length of iCCP profiles (Larry Reeves).
+  Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate
+    libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h
+  Revised makefile.darwin to remove "-undefined suppress" option.
+  Added checks for gamma and chromaticity values over 21474.83, which exceed
+    the limit for PNG unsigned 32-bit integers when encoded.
+  Revised calls to png_create_read_struct() and png_create_write_struct()
+    for simpler debugging.
+  Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK)
+
+Version 1.2.2beta2 [February 23, 2002]
+  Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths.
+  Check for invalid image dimensions in png_get_IHDR.
+  Added missing "fi;" in the install target of the SGI makefiles.
+  Added install-static to all makefiles that make shared libraries.
+  Always do gamma compensation when image is partially transparent.
+
+Version 1.2.2beta3 [March 7, 2002]
+  Compute background.gray and background_1.gray even when color_type is RGB
+    in case image gets reduced to gray later.
+  Modified shared-library makefiles to install pkgconfig/libpngNN.pc.
+  Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown
+  Removed unused png_write_destroy_info prototype from png.h
+  Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case
+  Added install-shared target to all makefiles that make shared libraries.
+  Stopped a double free of palette, hist, and trans when not using free_me.
+  Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64.
+
+Version 1.2.2beta4 [March 8, 2002]
+  Compute background.gray and background_1.gray even when color_type is RGB
+    in case image gets reduced to gray later (Jason Summers).
+  Relocated a misplaced /bin/rm in the "install-shared" makefile targets
+  Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library.
+
+Version 1.2.2beta5 [March 26, 2002]
+  Added missing PNGAPI to several function definitions.
+  Check for invalid bit_depth or color_type in png_get_IHDR(), and
+    check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen).
+  Revised iTXt support to accept NULL for lang and lang_key.
+  Compute gamma for color components of background even when color_type is gray.
+  Changed "()" to "{}" in scripts/libpng.pc.in.
+  Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN
+  Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so
+
+Version 1.2.2beta6 [March 31, 2002]
+
+Version 1.0.13beta1 [March 31, 2002]
+  Prevent png_zalloc() from trying to memset memory that it failed to acquire.
+  Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate).
+  Ensure that the right function (user or default) is used to free the
+    png_struct after an error in png_create_read_struct_2().
+
+Version 1.2.2rc1 [April 7, 2002]
+
+Version 1.0.13rc1 [April 7, 2002]
+  Save the ebx register in pnggccrd.c (Sami Farin)
+  Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner).
+  Updated makefiles to put headers in include/libpng and remove old include/*.h.
+
+Version 1.2.2 [April 15, 2002]
+
+Version 1.0.13 [April 15, 2002]
+  Revised description of png_set_filter() in libpng.3/libpng.txt.
+  Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd
+
+Version 1.0.13patch01 [April 17, 2002]
+
+Version 1.2.2patch01 [April 17, 2002]
+  Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and
+    makefile.sggcc
+  Fixed VER -> PNGVER typo in makefile.macosx and added install-static to
+    install
+  Added install: target to makefile.32sunu and makefile.64sunu
+
+Version 1.0.13patch03 [April 18, 2002]
+
+Version 1.2.2patch03 [April 18, 2002]
+  Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng
+  subdirectory to libpngNN subdirectory without the full pathname.
+  Moved generation of libpng.pc from "install" to "all" in 15 makefiles.
+
+Version 1.2.3rc1 [April 28, 2002]
+  Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos).
+  Added $(DESTDIR) feature to 24 makefiles (Tim Mooney)
+  Fixed bug with $prefix, should be $(prefix) in makefile.hpux.
+  Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin
+  Added a link from libpngNN.pc to libpng.pc in 15 makefiles.
+  Added links from include/libpngNN/*.h to include/*.h in 24 makefiles.
+  Revised makefile.darwin to make relative links without full pathname.
+  Added setjmp() at the end of png_create_*_struct_2() in case user forgets
+    to put one in their application.
+  Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and
+    removed them from module definition files.
+
+Version 1.2.3rc2 [May 1, 2002]
+  Fixed bug in reporting number of channels in pngget.c and pngset.c,
+    that was introduced in version 1.2.2beta5.
+  Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(),
+    png_default_flush(), and png_push_fill_buffer() and included them in
+    module definition files.
+  Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles.
+
+Version 1.2.3rc3 [May 1, 2002]
+  Revised prototype for png_default_flush()
+  Remove old libpng.pc and libpngNN.pc before installing new ones.
+
+Version 1.2.3rc4 [May 2, 2002]
+  Typos in *.def files (png_default_read|write -> png_default_read|write_data)
+  In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc
+  Added libpng-config and libpngNN-config and modified makefiles to install
+    them.
+  Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles
+  Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp
+
+Version 1.2.3rc5 [May 11, 2002]
+  Changed "error" and "message" in prototypes to "error_message" and
+    "warning_message" to avoid namespace conflict.
+  Revised 15 makefiles to build libpng-config from libpng-config-*.in
+  Once more restored png_zalloc and png_zfree to regular nonexported form.
+  Restored png_default_read|write_data, png_default_flush, png_read_fill_buffer
+    to nonexported form, but with PNGAPI, and removed them from module def
+    files.
+
+Version 1.2.3rc6 [May 14, 2002]
+  Removed "PNGAPI" from png_zalloc() and png_zfree() in png.c
+  Changed "Gz" to "Gd" in projects/msvc/libpng.dsp and zlib.dsp.
+  Removed leftover libpng-config "sed" script from four makefiles.
+  Revised libpng-config creating script in 16 makefiles.
+
+Version 1.2.3 [May 22, 2002]
+  Revised libpng-config target in makefile.cygwin.
+  Removed description of png_set_mem_fn() from documentation.
+  Revised makefile.freebsd.
+  Minor cosmetic changes to 15 makefiles, e.g., $(DI) = $(DESTDIR)/$(INCDIR).
+  Revised projects/msvc/README.txt
+  Changed -lpng to -lpngNN in LDFLAGS in several makefiles.
+
+Version 1.2.4beta1 [May 24, 2002]
+  Added libpng.pc and libpng-config to "all:" target in 16 makefiles.
+  Fixed bug in 16 makefiles: $(DESTDIR)/$(LIBPATH) to $(DESTDIR)$(LIBPATH)
+  Added missing "\" before closing double quote in makefile.gcmmx.
+  Plugged various memory leaks; added png_malloc_warn() and png_set_text_2()
+    functions.
+
+Version 1.2.4beta2 [June 25, 2002]
+  Plugged memory leak of png_ptr->current_text (Matt Holgate).
+  Check for buffer overflow before reading CRC in pngpread.c (Warwick Allison)
+  Added -soname to the loader flags in makefile.dec, makefile.sgi, and
+    makefile.sggcc.
+  Added "test-installed" target to makefile.linux, makefile.gcmmx,
+    makefile.sgi, and makefile.sggcc.
+
+Version 1.2.4beta3 [June 28, 2002]
+  Plugged memory leak of row_buf in pngtest.c when there is a png_error().
+  Detect buffer overflow in pngpread.c when IDAT is corrupted with extra data.
+  Added "test-installed" target to makefile.32sunu, makefile.64sunu,
+    makefile.beos, makefile.darwin, makefile.dec, makefile.macosx,
+    makefile.solaris, makefile.hpux, makefile.hpgcc, and makefile.so9.
+
+Version 1.2.4rc1 and 1.0.14rc1 [July 2, 2002]
+  Added "test-installed" target to makefile.cygwin and makefile.sco.
+  Revised pnggccrd.c to be able to back out version 1.0.x via PNG_1_0_X macro.
+
+Version 1.2.4 and 1.0.14 [July 8, 2002]
+  Changed png_warning() to png_error() when width is too large to process.
+
+Version 1.2.4patch01 [July 20, 2002]
+  Revised makefile.cygwin to use DLL number 12 instead of 13.
+
+Version 1.2.5beta1 [August 6, 2002]
+  Added code to contrib/gregbook/readpng2.c to ignore unused chunks.
+  Replaced toucan.png in contrib/gregbook (it has been corrupt since 1.0.11)
+  Removed some stray *.o files from contrib/gregbook.
+  Changed png_error() to png_warning() about "Too much data" in pngpread.c
+    and about "Extra compressed data" in pngrutil.c.
+  Prevent png_ptr->pass from exceeding 7 in png_push_finish_row().
+  Updated makefile.hpgcc
+  Updated png.c and pnggccrd.c handling of return from png_mmx_support()
+
+Version 1.2.5beta2 [August 15, 2002]
+  Only issue png_warning() about "Too much data" in pngpread.c when avail_in
+    is nonzero.
+  Updated makefiles to install a separate libpng.so.3 with its own rpath.
+
+Version 1.2.5rc1 and 1.0.15rc1 [August 24, 2002]
+  Revised makefiles to not remove previous minor versions of shared libraries.
+
+Version 1.2.5rc2 and 1.0.15rc2 [September 16, 2002]
+  Revised 13 makefiles to remove "-lz" and "-L$(ZLIBLIB)", etc., from shared
+    library loader directive.
+  Added missing "$OBJSDLL" line to makefile.gcmmx.
+  Added missing "; fi" to makefile.32sunu.
+
+Version 1.2.5rc3 and 1.0.15rc3 [September 18, 2002]
+  Revised libpng-config script.
+
+Version 1.2.5 and 1.0.15 [October 3, 2002]
+  Revised makefile.macosx, makefile.darwin, makefile.hpgcc, and makefile.hpux,
+    and makefile.aix.
+  Relocated two misplaced PNGAPI lines in pngtest.c
+
+Version 1.2.6beta1 [October 22, 2002]
+  Commented out warning about uninitialized mmx_support in pnggccrd.c.
+  Changed "IBMCPP__" flag to "__IBMCPP__" in pngconf.h.
+  Relocated two more misplaced PNGAPI lines in pngtest.c
+  Fixed memory overrun bug in png_do_read_filler() with 16-bit datastreams,
+    introduced in version 1.0.2.
+  Revised makefile.macosx, makefile.dec, makefile.aix, and makefile.32sunu.
+
+Version 1.2.6beta2 [November 1, 2002]
+  Added libpng-config "--ldopts" output.
+  Added "AR=ar" and "ARFLAGS=rc" and changed "ar rc" to "$(AR) $(ARFLAGS)"
+    in makefiles.
+
+Version 1.2.6beta3 [July 18, 2004]
+  Reverted makefile changes from version 1.2.6beta2 and some of the changes
+    from version 1.2.6beta1; these will be postponed until version 1.2.7.
+    Version 1.2.6 is going to be a simple bugfix release.
+  Changed the one instance of "ln -sf" to "ln -f -s" in each Sun makefile.
+  Fixed potential overrun in pngerror.c by using strncpy instead of memcpy.
+  Added "#!/bin/sh" at the top of configure, for recognition of the
+    'x' flag under Cygwin (Cosmin).
+  Optimized vacuous tests that silence compiler warnings, in png.c (Cosmin).
+  Added support for PNG_USER_CONFIG, in pngconf.h (Cosmin).
+  Fixed the special memory handler for Borland C under DOS, in pngmem.c
+    (Cosmin).
+  Removed some spurious assignments in pngrutil.c (Cosmin).
+  Replaced 65536 with 65536L, and 0xffff with 0xffffL, to silence warnings
+    on 16-bit platforms (Cosmin).
+  Enclosed shift op expressions in parentheses, to silence warnings (Cosmin).
+  Used proper type png_fixed_point, to avoid problems on 16-bit platforms,
+    in png_handle_sRGB() (Cosmin).
+  Added compression_type to png_struct, and optimized the window size
+    inside the deflate stream (Cosmin).
+  Fixed definition of isnonalpha(), in pngerror.c and pngrutil.c (Cosmin).
+  Fixed handling of unknown chunks that come after IDAT (Cosmin).
+  Allowed png_error() and png_warning() to work even if png_ptr == NULL
+    (Cosmin).
+  Replaced row_info->rowbytes with row_bytes in png_write_find_filter()
+    (Cosmin).
+  Fixed definition of PNG_LIBPNG_VER_DLLNUM (Simon-Pierre).
+  Used PNG_LIBPNG_VER and PNG_LIBPNG_VER_STRING instead of the hardcoded
+    values in png.c (Simon-Pierre, Cosmin).
+  Initialized png_libpng_ver[] with PNG_LIBPNG_VER_STRING (Simon-Pierre).
+  Replaced PNG_LIBPNG_VER_MAJOR with PNG_LIBPNG_VER_DLLNUM in png.rc
+    (Simon-Pierre).
+  Moved the definition of PNG_HEADER_VERSION_STRING near the definitions
+    of the other PNG_LIBPNG_VER_... symbols in png.h (Cosmin).
+  Relocated #ifndef PNGAPI guards in pngconf.h (Simon-Pierre, Cosmin).
+  Updated scripts/makefile.vc(a)win32 (Cosmin).
+  Updated the MSVC project (Simon-Pierre, Cosmin).
+  Updated the Borland C++ Builder project (Cosmin).
+  Avoided access to asm_flags in pngvcrd.c, if PNG_1_0_X is defined (Cosmin).
+  Commented out warning about uninitialized mmx_support in pngvcrd.c (Cosmin).
+  Removed scripts/makefile.bd32 and scripts/pngdef.pas (Cosmin).
+  Added extra guard around inclusion of Turbo C memory headers, in pngconf.h
+    (Cosmin).
+  Renamed projects/msvc/ to projects/visualc6/, and projects/borland/ to
+    projects/cbuilder5/ (Cosmin).
+  Moved projects/visualc6/png32ms.def to scripts/pngw32.def,
+    and projects/visualc6/png.rc to scripts/pngw32.rc (Cosmin).
+  Added projects/visualc6/pngtest.dsp; removed contrib/msvctest/ (Cosmin).
+  Changed line endings to DOS style in cbuilder5 and visualc6 files, even
+    in the tar.* distributions (Cosmin).
+  Updated contrib/visupng/VisualPng.dsp (Cosmin).
+  Updated contrib/visupng/cexcept.h to version 2.0.0 (Cosmin).
+  Added a separate distribution with "configure" and supporting files (Junichi).
+
+Version 1.2.6beta4 [July 28, 2004]
+  Added user ability to change png_size_t via a PNG_SIZE_T macro.
+  Added png_sizeof() and png_convert_size() functions.
+  Added PNG_SIZE_MAX (maximum value of a png_size_t variable.
+  Added check in png_malloc_default() for (size_t)size != (png_uint_32)size
+    which would indicate an overflow.
+  Changed sPLT failure action from png_error to png_warning and abandon chunk.
+  Changed sCAL and iCCP failures from png_error to png_warning and abandon.
+  Added png_get_uint_31(png_ptr, buf) function.
+  Added PNG_UINT_32_MAX macro.
+  Renamed PNG_MAX_UINT to PNG_UINT_31_MAX.
+  Made png_zalloc() issue a png_warning and return NULL on potential
+    overflow.
+  Turn on PNG_NO_ZALLOC_ZERO by default in version 1.2.x
+  Revised "clobber list" in pnggccrd.c so it will compile under gcc-3.4.
+  Revised Borland portion of png_malloc() to return NULL or issue
+    png_error() according to setting of PNG_FLAG_MALLOC_NULL_MEM_OK.
+  Added PNG_NO_SEQUENTIAL_READ_SUPPORTED macro to conditionally remove
+    sequential read support.
+  Added some "#if PNG_WRITE_SUPPORTED" blocks.
+  Added #ifdef to remove some redundancy in png_malloc_default().
+  Use png_malloc instead of png_zalloc to allocate the palette.
+
+Version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
+  Fixed buffer overflow vulnerability (CVE-2004-0597) in png_handle_tRNS().
+  Fixed NULL dereference vulnerability (CVE-2004-0598) in png_handle_iCCP().
+  Fixed integer overflow vulnerability (CVE-2004-0599) in png_read_png().
+  Fixed some harmless bugs in png_handle_sBIT, etc, that would cause
+    duplicate chunk types to go undetected.
+  Fixed some timestamps in the -config version
+  Rearranged order of processing of color types in png_handle_tRNS().
+  Added ROWBYTES macro to calculate rowbytes without integer overflow.
+  Updated makefile.darwin and removed makefile.macosx from scripts directory.
+  Imposed default one million column, one-million row limits on the image
+    dimensions, and added png_set_user_limits() function to override them.
+  Revised use of PNG_SET_USER_LIMITS_SUPPORTED macro.
+  Fixed wrong cast of returns from png_get_user_width|height_max().
+  Changed some "keep the compiler happy" from empty statements to returns,
+  Revised libpng.txt to remove 1.2.x stuff from the 1.0.x distribution
+
+Version 1.0.16rc2 and 1.2.6rc2 [August 7, 2004]
+  Revised makefile.darwin and makefile.solaris.  Removed makefile.macosx.
+  Revised pngtest's png_debug_malloc() to use png_malloc() instead of
+    png_malloc_default() which is not supposed to be exported.
+  Fixed off-by-one error in one of the conversions to PNG_ROWBYTES() in
+    pngpread.c.  Bug was introduced in 1.2.6rc1.
+  Fixed bug in RGB to RGBX transformation introduced in 1.2.6rc1.
+  Fixed old bug in RGB to Gray transformation.
+  Fixed problem with 64-bit compilers by casting arguments to abs()
+    to png_int_32.
+  Changed "ln -sf" to "ln -f -s" in three makefiles (solaris, sco, so9).
+  Changed "HANDLE_CHUNK_*" to "PNG_HANDLE_CHUNK_*" (Cosmin)
+  Added "-@/bin/rm -f $(DL)/$(LIBNAME).so.$(PNGMAJ)" to 15 *NIX makefiles.
+  Added code to update the row_info->colortype in png_do_read_filler() (MSB).
+
+Version 1.0.16rc3 and 1.2.6rc3 [August 9, 2004]
+  Eliminated use of "abs()" in testing cHRM and gAMA values, to avoid
+    trouble with some 64-bit compilers.  Created PNG_OUT_OF_RANGE() macro.
+  Revised documentation of png_set_keep_unknown_chunks().
+  Check handle_as_unknown status in pngpread.c, as in pngread.c previously.
+  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_INTERNAL section of png.h
+  Added "rim" definitions for CONST4 and CONST6 in pnggccrd.c
+
+Version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004]
+  Fixed mistake in pngtest.c introduced in 1.2.6rc2 (declaration of
+    "pinfo" was out of place).
+
+Version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004]
+  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED
+    section of png.h where they were inadvertently placed in version rc3.
+
+Version 1.2.6 and 1.0.16 [August 15, 2004]
+  Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1.
+
+Version 1.2.7beta1 [August 26, 2004]
+  Removed unused pngasmrd.h file.
+  Removed references to uu.net for archived files.  Added references to
+    PNG Spec (second edition) and the PNG ISO/IEC Standard.
+  Added "test-dd" target in 15 makefiles, to run pngtest in DESTDIR.
+  Fixed bug with "optimized window size" in the IDAT datastream, that
+    causes libpng to write PNG files with incorrect zlib header bytes.
+
+Version 1.2.7beta2 [August 28, 2004]
+  Fixed bug with sCAL chunk and big-endian machines (David Munro).
+  Undid new code added in 1.2.6rc2 to update the color_type in
+    png_set_filler().
+  Added png_set_add_alpha() that updates color type.
+
+Version 1.0.17rc1 and 1.2.7rc1 [September 4, 2004]
+  Revised png_set_strip_filler() to not remove alpha if color_type has alpha.
+
+Version 1.2.7 and 1.0.17 [September 12, 2004]
+  Added makefile.hp64
+  Changed projects/msvc/png32ms.def to scripts/png32ms.def in makefile.cygwin
+
+Version 1.2.8beta1 [November 1, 2004]
+  Fixed bug in png_text_compress() that would fail to complete a large block.
+  Fixed bug, introduced in libpng-1.2.7, that overruns a buffer during
+    strip alpha operation in png_do_strip_filler().
+  Added PNG_1_2_X definition in pngconf.h
+  Use #ifdef to comment out png_info_init in png.c and png_read_init in
+    pngread.c (as of 1.3.0)
+
+Version 1.2.8beta2 [November 2, 2004]
+  Reduce color_type to a nonalpha type after strip alpha operation in
+    png_do_strip_filler().
+
+Version 1.2.8beta3 [November 3, 2004]
+  Revised definitions of PNG_MAX_UINT_32, PNG_MAX_SIZE, and PNG_MAXSUM
+
+Version 1.2.8beta4 [November 12, 2004]
+  Fixed (again) definition of PNG_LIBPNG_VER_DLLNUM in png.h (Cosmin).
+  Added PNG_LIBPNG_BUILD_PRIVATE in png.h (Cosmin).
+  Set png_ptr->zstream.data_type to Z_BINARY, to avoid unnecessary detection
+    of data type in deflate (Cosmin).
+  Deprecated but continue to support SPECIALBUILD and PRIVATEBUILD in favor of
+    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
+
+Version 1.2.8beta5 [November 20, 2004]
+  Use png_ptr->flags instead of png_ptr->transformations to pass
+    PNG_STRIP_ALPHA info to png_do_strip_filler(), to preserve ABI
+    compatibility.
+  Revised handling of SPECIALBUILD, PRIVATEBUILD,
+    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
+
+Version 1.2.8rc1 [November 24, 2004]
+  Moved handling of BUILD macros from pngconf.h to png.h
+  Added definition of PNG_LIBPNG_BASE_TYPE in png.h, inadvertently
+    omitted from beta5.
+  Revised scripts/pngw32.rc
+  Despammed mailing addresses by masking "@" with "at".
+  Inadvertently installed a supposedly faster test version of pngrutil.c
+
+Version 1.2.8rc2 [November 26, 2004]
+  Added two missing "\" in png.h
+  Change tests in pngread.c and pngpread.c to
+    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
+       png_do_read_transformations(png_ptr);
+
+Version 1.2.8rc3 [November 28, 2004]
+  Reverted pngrutil.c to version libpng-1.2.8beta5.
+  Added scripts/makefile.elf with supporting code in pngconf.h for symbol
+    versioning (John Bowler).
+
+Version 1.2.8rc4 [November 29, 2004]
+  Added projects/visualc7 (Simon-pierre).
+
+Version 1.2.8rc5 [November 29, 2004]
+  Fixed new typo in scripts/pngw32.rc
+
+Version 1.2.8 [December 3, 2004]
+  Removed projects/visualc7, added projects/visualc71.
+
+Version 1.2.9beta1 [February 21, 2006]
+  Initialized some structure members in pngwutil.c to avoid gcc-4.0.0 complaints
+  Revised man page and libpng.txt to make it clear that one should not call
+    png_read_end or png_write_end after png_read_png or png_write_png.
+  Updated references to png-mng-implement mailing list.
+  Fixed an incorrect typecast in pngrutil.c
+  Added PNG_NO_READ_SUPPORTED conditional for making a write-only library.
+  Added PNG_NO_WRITE_INTERLACING_SUPPORTED conditional.
+  Optimized alpha-inversion loops in pngwtran.c
+  Moved test for nonzero gamma outside of png_build_gamma_table() in pngrtran.c
+  Make sure num_trans is <= 256 before copying data in png_set_tRNS().
+  Make sure num_palette is <= 256 before copying data in png_set_PLTE().
+  Interchanged order of write_swap_alpha and write_invert_alpha transforms.
+  Added parentheses in the definition of PNG_LIBPNG_BUILD_TYPE (Cosmin).
+  Optimized zlib window flag (CINFO) in contrib/pngsuite/*.png (Cosmin).
+  Updated scripts/makefile.bc32 for Borland C++ 5.6 (Cosmin).
+  Exported png_get_uint_32, png_save_uint_32, png_get_uint_16, png_save_uint_16,
+    png_get_int_32, png_save_int_32, png_get_uint_31 (Cosmin).
+  Added type cast (png_byte) in png_write_sCAL() (Cosmin).
+  Fixed scripts/makefile.cygwin (Christian Biesinger, Cosmin).
+  Default iTXt support was inadvertently enabled.
+
+Version 1.2.9beta2 [February 21, 2006]
+  Check for png_rgb_to_gray and png_gray_to_rgb read transformations before
+    checking for png_read_dither in pngrtran.c
+  Revised checking of chromaticity limits to accommodate extended RGB
+    colorspace (John Denker).
+  Changed line endings in some of the project files to CRLF, even in the
+    "Unix" tar distributions (Cosmin).
+  Made png_get_int_32 and png_save_int_32 always available (Cosmin).
+  Updated scripts/pngos2.def, scripts/pngw32.def and projects/wince/png32ce.def
+    with the newly exported functions.
+  Eliminated distributions without the "configure" script.
+  Updated INSTALL instructions.
+
+Version 1.2.9beta3 [February 24, 2006]
+  Fixed CRCRLF line endings in contrib/visupng/VisualPng.dsp
+  Made libpng.pc respect EXEC_PREFIX (D. P. Kreil, J. Bowler)
+  Removed reference to pngasmrd.h from Makefile.am
+  Renamed CHANGES to ChangeLog.
+  Renamed LICENSE to COPYING.
+  Renamed ANNOUNCE to NEWS.
+  Created AUTHORS file.
+
+Version 1.2.9beta4 [March 3, 2006]
+  Changed definition of PKGCONFIG from $prefix/lib to $libdir in configure.ac
+  Reverted to filenames LICENSE and ANNOUNCE; removed AUTHORS and COPYING.
+  Removed newline from the end of some error and warning messages.
+  Removed test for sqrt() from configure.ac and configure.
+  Made swap tables in pngtrans.c PNG_CONST (Carlo Bramix).
+  Disabled default iTXt support that was inadvertently enabled in
+    libpng-1.2.9beta1.
+  Added "OS2" to list of systems that don't need underscores, in pnggccrd.c
+  Removed libpng version and date from *.c files.
+
+Version 1.2.9beta5 [March 4, 2006]
+  Removed trailing blanks from source files.
+  Put version and date of latest change in each source file, and changed
+    copyright year accordingly.
+  More cleanup of configure.ac, Makefile.am, and associated scripts.
+  Restored scripts/makefile.elf which was inadvertently deleted.
+
+Version 1.2.9beta6 [March 6, 2006]
+  Fixed typo (RELEASE) in configuration files.
+
+Version 1.2.9beta7 [March 7, 2006]
+  Removed libpng.vers and libpng.sym from libpng12_la_SOURCES in Makefile.am
+  Fixed inconsistent #ifdef's around png_sig_bytes() and png_set_sCAL_s()
+    in png.h.
+  Updated makefile.elf as suggested by debian.
+  Made cosmetic changes to some makefiles, adding LN_SF and other macros.
+  Made some makefiles accept "exec_prefix".
+
+Version 1.2.9beta8 [March 9, 2006]
+  Fixed some "#if defined (..." which should be "#if defined(..."
+    Bug introduced in libpng-1.2.8.
+  Fixed inconsistency in definition of png_default_read_data()
+  Restored blank that was lost from makefile.sggcc "clean" target in beta7.
+  Revised calculation of "current" and "major" for irix in ltmain.sh
+  Changed "mkdir" to "MKDIR_P" in some makefiles.
+  Separated PNG_EXPAND and PNG_EXPAND_tRNS.
+  Added png_set_expand_gray_1_2_4_to_8() and deprecated
+    png_set_gray_1_2_4_to_8() which also expands tRNS to alpha.
+
+Version 1.2.9beta9 [March 10, 2006]
+  Include "config.h" in pngconf.h when available.
+  Added some checks for NULL png_ptr or NULL info_ptr (timeless)
+
+Version 1.2.9beta10 [March 20, 2006]
+  Removed extra CR from contrib/visualpng/VisualPng.dsw (Cosmin)
+  Made pnggccrd.c PIC-compliant (Christian Aichinger).
+  Added makefile.mingw (Wolfgang Glas).
+  Revised pngconf.h MMX checking.
+
+Version 1.2.9beta11 [March 22, 2006]
+  Fixed out-of-order declaration in pngwrite.c that was introduced in beta9
+  Simplified some makefiles by using LIBSO, LIBSOMAJ, and LIBSOVER macros.
+
+Version 1.2.9rc1 [March 31, 2006]
+  Defined PNG_USER_PRIVATEBUILD when including "pngusr.h" (Cosmin).
+  Removed nonsensical assertion check from pngtest.c (Cosmin).
+
+Version 1.2.9 [April 14, 2006]
+  Revised makefile.beos and added "none" selector in ltmain.sh
+
+Version 1.2.10beta1 [April 15, 2006]
+  Renamed "config.h" to "png_conf.h" and revised Makefile.am to add
+    -DPNG_BUILDING_LIBPNG to compile directive, and modified pngconf.h
+    to include png_conf.h only when PNG_BUILDING_LIBPNG is defined.
+
+Version 1.2.10beta2 [April 15, 2006]
+  Manually updated Makefile.in and configure.  Changed png_conf.h.in
+    back to config.h.
+
+Version 1.2.10beta3 [April 15, 2006]
+  Change png_conf.h back to config.h in pngconf.h.
+
+Version 1.2.10beta4 [April 16, 2006]
+  Change PNG_BUILDING_LIBPNG to PNG_CONFIGURE_LIBPNG in config/Makefile*.
+
+Version 1.2.10beta5 [April 16, 2006]
+  Added a configure check for compiling assembler code in pnggccrd.c
+
+Version 1.2.10beta6 [April 17, 2006]
+  Revised the configure check for pnggccrd.c
+  Moved -DPNG_CONFIGURE_LIBPNG into @LIBPNG_DEFINES@
+  Added @LIBPNG_DEFINES@ to arguments when building libpng.sym
+
+Version 1.2.10beta7 [April 18, 2006]
+  Change "exec_prefix=$prefix" to "exec_prefix=$(prefix)" in makefiles.
+
+Version 1.2.10rc1 [April 19, 2006]
+  Ensure pngconf.h doesn't define both PNG_USE_PNGGCCRD and PNG_USE_PNGVCRD
+  Fixed "LN_FS" typo in makefile.sco and makefile.solaris.
+
+Version 1.2.10rc2 [April 20, 2006]
+  Added a backslash between -DPNG_CONFIGURE_LIBPNG and -DPNG_NO_ASSEMBLER_CODE
+   in configure.ac and configure
+  Made the configure warning about versioned symbols less arrogant.
+
+Version 1.2.10rc3 [April 21, 2006]
+  Added a note in libpng.txt that png_set_sig_bytes(8) can be used when
+    writing an embedded PNG without the 8-byte signature.
+  Revised makefiles and configure to avoid making links to libpng.so.*
+
+Version 1.2.10 [April 23, 2006]
+  Reverted configure to "rc2" state.
+
+Version 1.2.11beta1 [May 31, 2006]
+  scripts/libpng.pc.in contained "configure" style version info and would
+    not work with makefiles.
+  The shared-library makefiles were linking to libpng.so.0 instead of
+    libpng.so.3 compatibility as the library.
+
+Version 1.2.11beta2 [June 2, 2006]
+  Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+    buffer overflow.
+  Fixed bug in example.c (png_set_palette_rgb -> png_set_palette_to_rgb)
+
+Version 1.2.11beta3 [June 5, 2006]
+  Prepended "#! /bin/sh" to ltmail.sh and contrib/pngminus/*.sh (Cosmin).
+  Removed the accidental leftover Makefile.in~ (Cosmin).
+  Avoided potential buffer overflow and optimized buffer in
+    png_write_sCAL(), png_write_sCAL_s() (Cosmin).
+  Removed the include directories and libraries from CFLAGS and LDFLAGS
+    in scripts/makefile.gcc (Nelson A. de Oliveira, Cosmin).
+
+Version 1.2.11beta4 [June 6, 2006]
+  Allow zero-length IDAT chunks after the entire zlib datastream, but not
+    after another intervening chunk type.
+
+Version 1.0.19rc1, 1.2.11rc1 [June 13, 2006]
+  Deleted extraneous square brackets from [config.h] in configure.ac
+
+Version 1.0.19rc2, 1.2.11rc2 [June 14, 2006]
+  Added prototypes for PNG_INCH_CONVERSIONS functions to png.h
+  Revised INSTALL and autogen.sh
+  Fixed typo in several makefiles (-W1 should be -Wl)
+  Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
+
+Version 1.0.19rc3, 1.2.11rc3 [June 15, 2006]
+  Removed the new typedefs for 64-bit systems (delay until version 1.4.0)
+  Added one zero element to png_gamma_shift[] array in pngrtran.c to avoid
+    reading out of bounds.
+
+Version 1.0.19rc4, 1.2.11rc4 [June 15, 2006]
+  Really removed the new typedefs for 64-bit systems.
+
+Version 1.0.19rc5, 1.2.11rc5 [June 22, 2006]
+  Removed png_sig_bytes entry from scripts/pngw32.def
+
+Version 1.0.19, 1.2.11 [June 26, 2006]
+  None.
+
+Version 1.0.20, 1.2.12 [June 27, 2006]
+  Really increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+    buffer overflow.
+
+Version 1.2.13beta1 [October 2, 2006]
+  Removed AC_FUNC_MALLOC from configure.ac
+  Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
+  Change "logical" to "bitwise" throughout documentation.
+  Detect and fix attempt to write wrong iCCP profile length (CVE-2006-7244)
+
+Version 1.0.21, 1.2.13 [November 14, 2006]
+  Fix potential buffer overflow in sPLT chunk handler.
+  Fix Makefile.am to not try to link to noexistent files.
+  Check all exported functions for NULL png_ptr.
+
+Version 1.2.14beta1 [November 17, 2006]
+  Relocated three misplaced tests for NULL png_ptr.
+  Built Makefile.in with automake-1.9.6 instead of 1.9.2.
+  Build configure with autoconf-2.60 instead of 2.59
+
+Version 1.2.14beta2 [November 17, 2006]
+  Added some typecasts in png_zalloc().
+
+Version 1.2.14rc1 [November 20, 2006]
+  Changed "strtod" to "png_strtod" in pngrutil.c
+
+Version 1.0.22, 1.2.14    [November 27, 2006]
+  Added missing "$(srcdir)" in Makefile.am and Makefile.in
+
+Version 1.2.15beta1 [December 3, 2006]
+  Generated configure with autoconf-2.61 instead of 2.60
+  Revised configure.ac to update libpng.pc and libpng-config.
+
+Version 1.2.15beta2 [December 3, 2006]
+  Always export MMX asm functions, just stubs if not building pnggccrd.c
+
+Version 1.2.15beta3 [December 4, 2006]
+  Add "png_bytep" typecast to profile while calculating length in pngwutil.c
+
+Version 1.2.15beta4 [December 7, 2006]
+  Added scripts/CMakeLists.txt
+  Changed PNG_NO_ASSEMBLER_CODE to PNG_NO_MMX_CODE in scripts, like 1.4.0beta
+
+Version 1.2.15beta5 [December 7, 2006]
+  Changed some instances of PNG_ASSEMBLER_* to PNG_MMX_* in pnggccrd.c
+  Revised scripts/CMakeLists.txt
+
+Version 1.2.15beta6 [December 13, 2006]
+  Revised scripts/CMakeLists.txt and configure.ac
+
+Version 1.2.15rc1 [December 18, 2006]
+  Revised scripts/CMakeLists.txt
+
+Version 1.2.15rc2 [December 21, 2006]
+  Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
+  Added scripts/makefile.nommx
+
+Version 1.2.15rc3 [December 25, 2006]
+  Fixed shared library numbering error that was introduced in 1.2.15beta6.
+
+Version 1.2.15rc4 [December 27, 2006]
+  Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set.
+
+Version 1.2.15rc5 [December 31, 2006]
+  Revised handling of rgb_to_gray.
+
+Version 1.2.15 [January 5, 2007]
+  Added some (unsigned long) typecasts in pngtest.c to avoid printing errors.
+
+Version 1.2.16beta1 [January 6, 2007]
+  Fix bugs in makefile.nommx
+
+Version 1.2.16beta2 [January 16, 2007]
+  Revised scripts/CMakeLists.txt
+
+Version 1.2.16 [January 31, 2007]
+  No changes.
+
+Version 1.2.17beta1 [March 6, 2007]
+  Revised scripts/CMakeLists.txt to install both shared and static libraries.
+  Deleted a redundant line from pngset.c.
+
+Version 1.2.17beta2 [April 26, 2007]
+  Relocated misplaced test for png_ptr == NULL in pngpread.c
+  Change "==" to "&" for testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN
+    flags.
+  Changed remaining instances of PNG_ASSEMBLER_* to PNG_MMX_*
+  Added pngerror() when write_IHDR fails in deflateInit2().
+  Added "const" to some array declarations.
+  Mention examples of libpng usage in the libpng*.txt and libpng.3 documents.
+
+Version 1.2.17rc1 [May 4, 2007]
+  No changes.
+
+Version 1.2.17rc2 [May 8, 2007]
+  Moved several PNG_HAVE_* macros out of PNG_INTERNAL because applications
+    calling set_unknown_chunk_location() need them.
+  Changed transformation flag from PNG_EXPAND_tRNS to PNG_EXPAND in
+    png_set_expand_gray_1_2_4_to_8().
+  Added png_ptr->unknown_chunk to hold working unknown chunk data, so it
+    can be free'ed in case of error.  Revised unknown chunk handling in
+    pngrutil.c and pngpread.c to use this structure.
+
+Version 1.2.17rc3 [May 8, 2007]
+  Revised symbol-handling in configure script.
+
+Version 1.2.17rc4 [May 10, 2007]
+  Revised unknown chunk handling to avoid storing unknown critical chunks.
+
+Version 1.0.25 [May 15, 2007]
+Version 1.2.17 [May 15, 2007]
+  Added "png_ptr->num_trans=0" before error return in png_handle_tRNS,
+    to eliminate a vulnerability (CVE-2007-2445, CERT VU#684664)
+
+Version 1.0.26 [May 15, 2007]
+Version 1.2.18 [May 15, 2007]
+  Reverted the libpng-1.2.17rc3 change to symbol-handling in configure script
+
+Version 1.2.19beta1 [May 18, 2007]
+  Changed "const static" to "static PNG_CONST" everywhere, mostly undoing
+    change of libpng-1.2.17beta2.  Changed other "const" to "PNG_CONST"
+  Changed some handling of unused parameters, to avoid compiler warnings.
+    "if (unused == NULL) return;" becomes "unused = unused".
+
+Version 1.2.19beta2 [May 18, 2007]
+  Only use the valid bits of tRNS value in png_do_expand() (Brian Cartier)
+
+Version 1.2.19beta3 [May 19, 2007]
+  Add some "png_byte" typecasts in png_check_keyword() and write new_key
+  instead of key in zTXt chunk (Kevin Ryde).
+
+Version 1.2.19beta4 [May 21, 2007]
+  Add png_snprintf() function and use it in place of sprint() for improved
+    defense against buffer overflows.
+
+Version 1.2.19beta5 [May 21, 2007]
+  Fixed png_handle_tRNS() to only use the valid bits of tRNS value.
+  Changed handling of more unused parameters, to avoid compiler warnings.
+  Removed some PNG_CONST in pngwutil.c to avoid compiler warnings.
+
+Version 1.2.19beta6 [May 22, 2007]
+  Added some #ifdef PNG_MMX_CODE_SUPPORTED where needed in pngvcrd.c
+  Added a special "_MSC_VER" case that defines png_snprintf to _snprintf
+
+Version 1.2.19beta7 [May 22, 2007]
+  Squelched png_squelch_warnings() in pnggccrd.c and added
+    an #ifdef PNG_MMX_CODE_SUPPORTED block around the declarations that caused
+    the warnings that png_squelch_warnings was squelching.
+
+Version 1.2.19beta8 [May 22, 2007]
+  Removed __MMX__ from test in pngconf.h.
+
+Version 1.2.19beta9 [May 23, 2007]
+  Made png_squelch_warnings() available via PNG_SQUELCH_WARNINGS macro.
+  Revised png_squelch_warnings() so it might work.
+  Updated makefile.sgcc and makefile.solaris; added makefile.solaris-x86.
+
+Version 1.2.19beta10 [May 24, 2007]
+  Resquelched png_squelch_warnings(), use "__attribute__((used))" instead.
+
+Version 1.4.0beta1 [April 20, 2006]
+  Enabled iTXt support (changes png_struct, thus requires so-number change).
+  Cleaned up PNG_ASSEMBLER_CODE_SUPPORTED vs PNG_MMX_CODE_SUPPORTED
+  Eliminated PNG_1_0_X and PNG_1_2_X macros.
+  Removed deprecated functions png_read_init, png_write_init, png_info_init,
+    png_permit_empty_plte, png_set_gray_1_2_4_to_8, png_check_sig, and
+    removed the deprecated macro PNG_MAX_UINT.
+  Moved "PNG_INTERNAL" parts of png.h and pngconf.h into pngintrn.h
+  Removed many WIN32_WCE #ifdefs (Cosmin).
+  Reduced dependency on C-runtime library when on Windows (Simon-Pierre)
+  Replaced sprintf() with png_sprintf() (Simon-Pierre)
+
+Version 1.4.0beta2 [April 20, 2006]
+  Revised makefiles and configure to avoid making links to libpng.so.*
+  Moved some leftover MMX-related defines from pngconf.h to pngintrn.h
+  Updated scripts/pngos2.def, pngw32.def, and projects/wince/png32ce.def
+
+Version 1.4.0beta3 [May 10, 2006]
+  Updated scripts/pngw32.def to comment out MMX functions.
+  Added PNG_NO_GET_INT_32 and PNG_NO_SAVE_INT_32 macros.
+  Scripts/libpng.pc.in contained "configure" style version info and would
+    not work with makefiles.
+  Revised pngconf.h and added pngconf.h.in, so makefiles and configure can
+    pass defines to libpng and applications.
+
+Version 1.4.0beta4 [May 11, 2006]
+  Revised configure.ac, Makefile.am, and many of the makefiles to write
+    their defines in pngconf.h.
+
+Version 1.4.0beta5 [May 15, 2006]
+  Added a missing semicolon in Makefile.am and Makefile.in
+  Deleted extraneous square brackets from configure.ac
+
+Version 1.4.0beta6 [June 2, 2006]
+  Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+    buffer overflow.
+  Changed sonum from 0 to 1.
+  Removed unused prototype for png_check_sig() from png.h
+
+Version 1.4.0beta7 [June 16, 2006]
+  Exported png_write_sig (Cosmin).
+  Optimized buffer in png_handle_cHRM() (Cosmin).
+  Set pHYs = 2835 x 2835 pixels per meter, and added
+    sCAL = 0.352778e-3 x 0.352778e-3 meters, in pngtest.png (Cosmin).
+  Added png_set_benign_errors(), png_benign_error(), png_chunk_benign_error().
+  Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
+  Added "(unsigned long)" typecast on png_uint_32 variables in printf lists.
+
+Version 1.4.0beta8 [June 22, 2006]
+  Added demonstration of user chunk support in pngtest.c, to support the
+    public sTER chunk and a private vpAg chunk.
+
+Version 1.4.0beta9 [July 3, 2006]
+  Removed ordinals from scripts/pngw32.def and removed png_info_int and
+    png_set_gray_1_2_4_to_8 entries.
+  Inline call of png_get_uint_32() in png_get_uint_31().
+  Use png_get_uint_31() to get vpAg width and height in pngtest.c
+  Removed WINCE and Netware projects.
+  Removed standalone Y2KINFO file.
+
+Version 1.4.0beta10 [July 12, 2006]
+  Eliminated automatic copy of pngconf.h to pngconf.h.in from configure and
+    some makefiles, because it was not working reliably.  Instead, distribute
+    pngconf.h.in along with pngconf.h and cause configure and some of the
+    makefiles to update pngconf.h from pngconf.h.in.
+  Added pngconf.h to DEPENDENCIES in Makefile.am
+
+Version 1.4.0beta11 [August 19, 2006]
+  Removed AC_FUNC_MALLOC from configure.ac.
+  Added a warning when writing iCCP profile with mismatched profile length.
+  Patched pnggccrd.c to assemble on x86_64 platforms.
+  Moved chunk header reading into a separate function png_read_chunk_header()
+    in pngrutil.c.  The chunk header (len+sig) is now serialized in a single
+    operation (Cosmin).
+  Implemented support for I/O states. Added png_ptr member io_state, and
+    functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+    (Cosmin).
+  Added png_get_io_chunk_name and png_get_io_state to scripts/*.def (Cosmin).
+  Renamed scripts/pngw32.* to scripts/pngwin.* (Cosmin).
+  Removed the include directories and libraries from CFLAGS and LDFLAGS
+    in scripts/makefile.gcc (Cosmin).
+  Used png_save_uint_32() to set vpAg width and height in pngtest.c (Cosmin).
+  Cast to proper type when getting/setting vpAg units in pngtest.c (Cosmin).
+  Added pngintrn.h to the Visual C++ projects (Cosmin).
+  Removed scripts/list (Cosmin).
+  Updated copyright year in scripts/pngwin.def (Cosmin).
+  Removed PNG_TYPECAST_NULL and used standard NULL consistently (Cosmin).
+  Disallowed the user to redefine png_size_t, and enforced a consistent use
+    of png_size_t across libpng (Cosmin).
+  Changed the type of png_ptr->rowbytes, PNG_ROWBYTES() and friends
+    to png_size_t (Cosmin).
+  Removed png_convert_size() and replaced png_sizeof with sizeof (Cosmin).
+  Removed some unnecessary type casts (Cosmin).
+  Changed prototype of png_get_compression_buffer_size() and
+    png_set_compression_buffer_size() to work with png_size_t instead of
+    png_uint_32 (Cosmin).
+  Removed png_memcpy_check() and png_memset_check() (Cosmin).
+  Fixed a typo (png_byte --> png_bytep) in libpng.3 and libpng.txt (Cosmin).
+  Clarified that png_zalloc() does not clear the allocated memory,
+    and png_zalloc() and png_zfree() cannot be PNGAPI (Cosmin).
+  Renamed png_mem_size_t to png_alloc_size_t, fixed its definition in
+    pngconf.h, and used it in all memory allocation functions (Cosmin).
+  Renamed pngintrn.h to pngpriv.h, added a comment at the top of the file
+    mentioning that the symbols declared in that file are private, and
+    updated the scripts and the Visual C++ projects accordingly (Cosmin).
+  Removed circular references between pngconf.h and pngconf.h.in in
+    scripts/makefile.vc*win32 (Cosmin).
+  Removing trailing '.' from the warning and error messages (Cosmin).
+  Added pngdefs.h that is built by makefile or configure, instead of
+    pngconf.h.in (Glenn).
+  Detect and fix attempt to write wrong iCCP profile length.
+
+Version 1.4.0beta12 [October 19, 2006]
+  Changed "logical" to "bitwise" in the documentation.
+  Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
+  Add a typecast to stifle compiler warning in pngrutil.c
+
+Version 1.4.0beta13 [November 10, 2006]
+  Fix potential buffer overflow in sPLT chunk handler.
+  Fix Makefile.am to not try to link to noexistent files.
+
+Version 1.4.0beta14 [November 15, 2006]
+  Check all exported functions for NULL png_ptr.
+
+Version 1.4.0beta15 [November 17, 2006]
+  Relocated two misplaced tests for NULL png_ptr.
+  Built Makefile.in with automake-1.9.6 instead of 1.9.2.
+  Build configure with autoconf-2.60 instead of 2.59
+  Add "install: all" in Makefile.am so "configure; make install" will work.
+
+Version 1.4.0beta16 [November 17, 2006]
+  Added a typecast in png_zalloc().
+
+Version 1.4.0beta17 [December 4, 2006]
+  Changed "new_key[79] = '\0';" to "(*new_key)[79] = '\0';" in pngwutil.c
+  Add "png_bytep" typecast to profile while calculating length in pngwutil.c
+
+Version 1.4.0beta18 [December 7, 2006]
+  Added scripts/CMakeLists.txt
+
+Version 1.4.0beta19 [May 16, 2007]
+  Revised scripts/CMakeLists.txt
+  Rebuilt configure and Makefile.in with newer tools.
+  Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
+  Added scripts/makefile.nommx
+
+Version 1.4.0beta20 [July 9, 2008]
+  Moved several PNG_HAVE_* macros from pngpriv.h to png.h because applications
+    calling set_unknown_chunk_location() need them.
+  Moved several macro definitions from pngpriv.h to pngconf.h
+  Merge with changes to the 1.2.X branch, as of 1.2.30beta04.
+  Deleted all use of the MMX assembler code and Intel-licensed optimizations.
+  Revised makefile.mingw
+
+Version 1.4.0beta21 [July 21, 2008]
+  Moved local array "chunkdata" from pngrutil.c to the png_struct, so
+    it will be freed by png_read_destroy() in case of a read error (Kurt
+    Christensen).
+
+Version 1.4.0beta22 [July 21, 2008]
+  Change "purpose" and "buffer" to png_ptr->chunkdata to avoid memory leaking.
+
+Version 1.4.0beta23 [July 22, 2008]
+  Change "chunkdata = NULL" to "png_ptr->chunkdata = NULL" several places in
+    png_decompress_chunk().
+
+Version 1.4.0beta24 [July 25, 2008]
+  Change all remaining "chunkdata" to "png_ptr->chunkdata" in
+    png_decompress_chunk(), and remove "chunkdata" from parameter list.
+  Put a call to png_check_chunk_name() in png_read_chunk_header().
+  Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte.
+  Removed two calls to png_check_chunk_name() occurring later in the process.
+  Define PNG_NO_ERROR_NUMBERS by default in pngconf.h
+
+Version 1.4.0beta25 [July 30, 2008]
+  Added a call to png_check_chunk_name() in pngpread.c
+  Reverted png_check_chunk_name() to accept a name with a lowercase 3rd byte.
+  Added png_push_have_buffer() function to pngpread.c
+  Eliminated PNG_BIG_ENDIAN_SUPPORTED and associated png_get_* macros.
+  Made inline expansion of png_get_*() optional with PNG_USE_READ_MACROS.
+  Eliminated all PNG_USELESS_TESTS and PNG_CORRECT_PALETTE_SUPPORTED code.
+  Synced contrib directory and configure files with libpng-1.2.30beta06.
+  Eliminated no-longer-used pngdefs.h (but it's still built in the makefiles)
+  Relocated a misplaced "#endif /* PNG_NO_WRITE_FILTER */" in pngwutil.c
+
+Version 1.4.0beta26 [August 4, 2008]
+  Removed png_push_have_buffer() function in pngpread.c.  It increased the
+    compiled library size slightly.
+  Changed "-Wall" to "-W -Wall" in the CFLAGS in all makefiles (Cosmin Truta)
+  Declared png_ptr "volatile" in pngread.c and pngwrite.c to avoid warnings.
+  Updated contrib/visupng/cexcept.h to version 2.0.1
+  Added PNG_LITERAL_CHARACTER macros for #, [, and ].
+
+Version 1.4.0beta27 [August 5, 2008]
+  Revised usage of PNG_LITERAL_SHARP in pngerror.c.
+  Moved newline character from individual png_debug messages into the
+    png_debug macros.
+  Allow user to #define their own png_debug, png_debug1, and png_debug2.
+
+Version 1.4.0beta28 [August 5, 2008]
+  Revised usage of PNG_LITERAL_SHARP in pngerror.c.
+  Added PNG_STRING_NEWLINE macro
+
+Version 1.4.0beta29 [August 9, 2008]
+  Revised usage of PNG_STRING_NEWLINE to work on non-ISO compilers.
+  Added PNG_STRING_COPYRIGHT macro.
+  Added non-ISO versions of png_debug macros.
+
+Version 1.4.0beta30 [August 14, 2008]
+  Added premultiplied alpha feature (Volker Wiendl).
+
+Version 1.4.0beta31 [August 18, 2008]
+  Moved png_set_premultiply_alpha from pngtrans.c to pngrtran.c
+  Removed extra crc check at the end of png_handle_cHRM().  Bug introduced
+    in libpng-1.4.0beta20.
+
+Version 1.4.0beta32 [August 19, 2008]
+  Added PNG_WRITE_FLUSH_SUPPORTED block around new png_flush() call.
+  Revised PNG_NO_STDIO version of png_write_flush()
+
+Version 1.4.0beta33 [August 20, 2008]
+  Added png_get|set_chunk_cache_max() to limit the total number of sPLT,
+    text, and unknown chunks that can be stored.
+
+Version 1.4.0beta34 [September 6, 2008]
+  Shortened tIME_string to 29 bytes in pngtest.c
+  Fixed off-by-one error introduced in png_push_read_zTXt() function in
+    libpng-1.2.30beta04/pngpread.c (Harald van Dijk)
+
+Version 1.4.0beta35 [October 6, 2008]
+  Changed "trans_values" to "trans_color".
+  Changed so-number from 0 to 14.  Some OS do not like 0.
+  Revised makefile.darwin to fix shared library numbering.
+  Change png_set_gray_1_2_4_to_8() to png_set_expand_gray_1_2_4_to_8()
+    in example.c (debian bug report)
+
+Version 1.4.0beta36 [October 25, 2008]
+  Sync with tEXt vulnerability fix in libpng-1.2.33rc02.
+
+Version 1.4.0beta37 [November 13, 2008]
+  Added png_check_cHRM in png.c and moved checking from pngget.c, pngrutil.c,
+    and pngwrite.c
+
+Version 1.4.0beta38 [November 22, 2008]
+  Added check for zero-area RGB cHRM triangle in png_check_cHRM() and
+    png_check_cHRM_fixed().
+
+Version 1.4.0beta39 [November 23, 2008]
+  Revised png_warning() to write its message on standard output by default
+    when warning_fn is NULL.
+
+Version 1.4.0beta40 [November 24, 2008]
+  Eliminated png_check_cHRM().  Instead, always use png_check_cHRM_fixed().
+  In png_check_cHRM_fixed(), ensure white_y is > 0, and removed redundant
+    check for all-zero coordinates that is detected by the triangle check.
+
+Version 1.4.0beta41 [November 26, 2008]
+  Fixed string vs pointer-to-string error in png_check_keyword().
+  Rearranged test expressions in png_check_cHRM_fixed() to avoid internal
+    overflows.
+  Added PNG_NO_CHECK_cHRM conditional.
+
+Version 1.4.0beta42, 43 [December 1, 2008]
+  Merge png_debug with version 1.2.34beta04.
+
+Version 1.4.0beta44 [December 6, 2008]
+  Removed redundant check for key==NULL before calling png_check_keyword()
+    to ensure that new_key gets initialized and removed extra warning
+    (Merge with version 1.2.34beta05 -- Arvan Pritchard).
+
+Version 1.4.0beta45 [December 9, 2008]
+  In png_write_png(), respect the placement of the filler bytes in an earlier
+    call to png_set_filler() (Jim Barry).
+
+Version 1.4.0beta46 [December 10, 2008]
+  Undid previous change and added PNG_TRANSFORM_STRIP_FILLER_BEFORE and
+    PNG_TRANSFORM_STRIP_FILLER_AFTER conditionals and deprecated
+    PNG_TRANSFORM_STRIP_FILLER (Jim Barry).
+
+Version 1.4.0beta47 [December 15, 2008]
+  Support for dithering was disabled by default, because it has never
+    been well tested and doesn't work very well.  The code has not
+    been removed, however, and can be enabled by building libpng with
+    PNG_READ_DITHER_SUPPORTED defined.
+
+Version 1.4.0beta48 [February 14, 2009]
+  Added new exported function png_calloc().
+  Combined several instances of png_malloc(); png_memset() into png_calloc().
+  Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
+    but was never defined.
+
+Version 1.4.0beta49 [February 28, 2009]
+  Added png_fileno() macro to pngconf.h, used in pngwio.c
+  Corrected order of #ifdef's in png_debug definition in png.h
+  Fixed bug introduced in libpng-1.4.0beta48 with the memset arguments
+    for pcal_params.
+  Fixed order of #ifdef directives in the png_debug defines in png.h
+    (bug introduced in libpng-1.2.34/1.4.0beta29).
+  Revised comments in png_set_read_fn() and png_set_write_fn().
+
+Version 1.4.0beta50 [March 18, 2009]
+  Use png_calloc() instead of png_malloc() to allocate big_row_buf when
+    reading an interlaced file, to avoid a possible UMR.
+  Undid revision of PNG_NO_STDIO version of png_write_flush().  Users
+    having trouble with fflush() can build with PNG_NO_WRITE_FLUSH defined
+    or supply their own flush_fn() replacement.
+  Revised libpng*.txt and png.h documentation about use of png_write_flush()
+    and png_set_write_fn().
+  Removed fflush() from pngtest.c.
+  Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
+
+Version 1.4.0beta51 [March 21, 2009]
+  Removed new png_fileno() macro from pngconf.h .
+
+Version 1.4.0beta52 [March 27, 2009]
+  Relocated png_do_chop() ahead of building gamma tables in pngrtran.c
+    This avoids building 16-bit gamma tables unnecessarily.
+  Removed fflush() from pngtest.c.
+  Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
+  Added a section on differences between 1.0.x and 1.2.x to libpng.3/libpng.txt
+
+Version 1.4.0beta53 [April 1, 2009]
+  Removed some remaining MMX macros from pngpriv.h
+  Fixed potential memory leak of "new_name" in png_write_iCCP() (Ralph Giles)
+
+Version 1.4.0beta54 [April 13, 2009]
+  Added "ifndef PNG_SKIP_SETJMP_CHECK" block in pngconf.h to allow
+    application code writers to bypass the check for multiple inclusion
+    of setjmp.h when they know that it is safe to ignore the situation.
+  Eliminated internal use of setjmp() in pngread.c and pngwrite.c
+  Reordered ancillary chunks in pngtest.png to be the same as what
+    pngtest now produces, and made some cosmetic changes to pngtest output.
+  Eliminated deprecated png_read_init_3() and png_write_init_3() functions.
+
+Version 1.4.0beta55 [April 15, 2009]
+  Simplified error handling in pngread.c and pngwrite.c by putting
+    the new png_read_cleanup() and png_write_cleanup() functions inline.
+
+Version 1.4.0beta56 [April 25, 2009]
+  Renamed "user_chunk_data" to "my_user_chunk_data" in pngtest.c to suppress
+    "shadowed declaration" warning from gcc-4.3.3.
+  Renamed "gamma" to "png_gamma" in pngset.c to avoid "shadowed declaration"
+    warning about a global "gamma" variable in math.h on some platforms.
+
+Version 1.4.0beta57 [May 2, 2009]
+  Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
+    but was never defined (again).
+  Rebuilt configure scripts with autoconf-2.63 instead of 2.62
+  Removed pngprefs.h and MMX from makefiles
+
+Version 1.4.0beta58 [May 14, 2009]
+  Changed pngw32.def to pngwin.def in makefile.mingw (typo was introduced
+    in beta57).
+  Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri)
+
+Version 1.4.0beta59 [May 15, 2009]
+  Reformated sources in libpng style (3-space intentation, comment format)
+  Fixed typo in libpng docs (PNG_FILTER_AVE should be PNG_FILTER_AVG)
+  Added sections about the git repository and our coding style to the
+    documentation
+  Relocated misplaced #endif in pngwrite.c, sCAL chunk handler.
+
+Version 1.4.0beta60 [May 19, 2009]
+  Conditionally compile png_read_finish_row() which is not used by
+    progressive readers.
+  Added contrib/pngminim/preader to demonstrate building minimal progressive
+    decoder, based on contrib/gregbook with embedded libpng and zlib.
+
+Version 1.4.0beta61 [May 20, 2009]
+  In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there
+    is only one makefile in those directories, and revised the README files
+    accordingly.
+  More reformatting of comments, mostly to capitalize sentences.
+
+Version 1.4.0beta62 [June 2, 2009]
+  Added "#define PNG_NO_WRITE_SWAP" to contrib/pngminim/encoder/pngusr.h
+    and "define PNG_NO_READ_SWAP" to decoder/pngusr.h and preader/pngusr.h
+  Reformatted several remaining "else statement" into two lines.
+  Added a section to the libpng documentation about using png_get_io_ptr()
+    in configure scripts to detect the presence of libpng.
+
+Version 1.4.0beta63 [June 15, 2009]
+  Revised libpng*.txt and libpng.3 to mention calling png_set_IHDR()
+    multiple times and to specify the sample order in the tRNS chunk,
+    because the ISO PNG specification has a typo in the tRNS table.
+  Changed several PNG_UNKNOWN_CHUNK_SUPPORTED to
+    PNG_HANDLE_AS_UNKNOWN_SUPPORTED, to make the png_set_keep mechanism
+    available for ignoring known chunks even when not saving unknown chunks.
+  Adopted preference for consistent use of "#ifdef" and "#ifndef" versus
+    "#if defined()" and "if !defined()" where possible.
+
+Version 1.4.0beta64 [June 24, 2009]
+  Eliminated PNG_LEGACY_SUPPORTED code.
+  Moved the various unknown chunk macro definitions outside of the
+    PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks.
+
+Version 1.4.0beta65 [June 26, 2009]
+  Added a reference to the libpng license in each file.
+
+Version 1.4.0beta66 [June 27, 2009]
+  Refer to the libpng license instead of the libpng license in each file.
+
+Version 1.4.0beta67 [July 6, 2009]
+  Relocated INVERT_ALPHA within png_read_png() and png_write_png().
+  Added high-level API transform PNG_TRANSFORM_GRAY_TO_RGB.
+  Added an "xcode" project to the projects directory (Alam Arias).
+
+Version 1.4.0beta68 [July 19, 2009]
+  Avoid some tests in filter selection in pngwutil.c
+
+Version 1.4.0beta69 [July 25, 2009]
+  Simplified the new filter-selection test.  This runs faster in the
+    common "PNG_ALL_FILTERS" and PNG_FILTER_NONE cases.
+  Removed extraneous declaration from the new call to png_read_gray_to_rgb()
+    (bug introduced in libpng-1.4.0beta67).
+  Fixed up xcode project (Alam Arias)
+  Added a prototype for png_64bit_product() in png.c
+
+Version 1.4.0beta70 [July 27, 2009]
+  Avoid a possible NULL dereference in debug build, in png_set_text_2().
+    (bug introduced in libpng-0.95, discovered by Evan Rouault)
+
+Version 1.4.0beta71 [July 29, 2009]
+  Rebuilt configure scripts with autoconf-2.64.
+
+Version 1.4.0beta72 [August 1, 2009]
+  Replaced *.tar.lzma with *.tar.xz in distribution.  Get the xz codec
+    from <http://tukaani.org/xz>.
+
+Version 1.4.0beta73 [August 1, 2009]
+  Reject attempt to write iCCP chunk with negative embedded profile length
+    (JD Chen) (CVE-2009-5063).
+
+Version 1.4.0beta74 [August 8, 2009]
+  Changed png_ptr and info_ptr member "trans" to "trans_alpha".
+
+Version 1.4.0beta75 [August 21, 2009]
+  Removed an extra png_debug() recently added to png_write_find_filter().
+  Fixed incorrect #ifdef in pngset.c regarding unknown chunk support.
+
+Version 1.4.0beta76 [August 22, 2009]
+  Moved an incorrectly located test in png_read_row() in pngread.c
+
+Version 1.4.0beta77 [August 27, 2009]
+  Removed lpXYZ.tar.bz2 (with CRLF), KNOWNBUG, libpng-x.y.z-KNOWNBUG.txt,
+    and the "noconfig" files from the distribution.
+  Moved CMakeLists.txt from scripts into the main libpng directory.
+  Various bugfixes and improvements to CMakeLists.txt (Philip Lowman)
+
+Version 1.4.0beta78 [August 31, 2009]
+  Converted all PNG_NO_* tests to PNG_*_SUPPORTED everywhere except pngconf.h
+  Eliminated PNG_NO_FREE_ME and PNG_FREE_ME_SUPPORTED macros.
+  Use png_malloc plus a loop instead of png_calloc() to initialize
+    row_pointers in png_read_png().
+
+Version 1.4.0beta79 [September 1, 2009]
+  Eliminated PNG_GLOBAL_ARRAYS and PNG_LOCAL_ARRAYS; always use local arrays.
+  Eliminated PNG_CALLOC_SUPPORTED macro and always provide png_calloc().
+
+Version 1.4.0beta80 [September 17, 2009]
+  Removed scripts/libpng.icc
+  Changed typecast of filler from png_byte to png_uint_16 in png_set_filler().
+    (Dennis Gustafsson)
+  Fixed typo introduced in beta78 in pngtest.c ("#if def " should be "#ifdef ")
+
+Version 1.4.0beta81 [September 23, 2009]
+  Eliminated unused PNG_FLAG_FREE_* defines from pngpriv.h
+  Expanded TAB characters in pngrtran.c
+  Removed PNG_CONST from all "PNG_CONST PNG_CHNK" declarations to avoid
+    compiler complaints about doubly declaring things "const".
+  Changed all "#if [!]defined(X)" to "if[n]def X" where possible.
+  Eliminated unused png_ptr->row_buf_size
+
+Version 1.4.0beta82 [September 25, 2009]
+  Moved redundant IHDR checking into new png_check_IHDR() in png.c
+    and report all errors found in the IHDR data.
+  Eliminated useless call to png_check_cHRM() from pngset.c
+
+Version 1.4.0beta83 [September 25, 2009]
+  Revised png_check_IHDR() to eliminate bogus complaint about filter_type.
+
+Version 1.4.0beta84 [September 30, 2009]
+  Fixed some inconsistent indentation in pngconf.h
+  Revised png_check_IHDR() to add a test for width variable less than 32-bit.
+
+Version 1.4.0beta85 [October 1, 2009]
+  Revised png_check_IHDR() again, to check info_ptr members instead of
+    the contents of the returned parameters.
+
+Version 1.4.0beta86 [October 9, 2009]
+  Updated the "xcode" project (Alam Arias).
+  Eliminated a shadowed declaration of "pp" in png_handle_sPLT().
+
+Version 1.4.0rc01 [October 19, 2009]
+  Trivial cosmetic changes.
+
+Version 1.4.0beta87 [October 30, 2009]
+  Moved version 1.4.0 back into beta.
+
+Version 1.4.0beta88 [October 30, 2009]
+  Revised libpng*.txt section about differences between 1.2.x and 1.4.0
+    because most of the new features have now been ported back to 1.2.41
+
+Version 1.4.0beta89 [November 1, 2009]
+  More bugfixes and improvements to CMakeLists.txt (Philip Lowman)
+  Removed a harmless extra png_set_invert_alpha() from pngwrite.c
+  Apply png_user_chunk_cache_max within png_decompress_chunk().
+  Merged libpng-1.2.41.txt with libpng-1.4.0.txt where appropriate.
+
+Version 1.4.0beta90 [November 2, 2009]
+  Removed all remaining WIN32_WCE #ifdefs except those involving the
+    time.h "tm" structure
+
+Version 1.4.0beta91 [November 3, 2009]
+  Updated scripts/pngw32.def and projects/wince/png32ce.def
+  Copied projects/wince/png32ce.def to the scripts directory.
+  Added scripts/makefile.wce
+  Patched ltmain.sh for wince support.
+  Added PNG_CONVERT_tIME_SUPPORTED macro.
+
+Version 1.4.0beta92 [November 4, 2009]
+  Make inclusion of time.h in pngconf.h depend on PNG_CONVERT_tIME_SUPPORTED
+  Make #define PNG_CONVERT_tIME_SUPPORTED depend on PNG_WRITE_tIME_SUPPORTED
+  Revised libpng*.txt to describe differences from 1.2.40 to 1.4.0 (instead
+    of differences from 1.2.41 to 1.4.0)
+
+Version 1.4.0beta93 [November 7, 2009]
+  Added PNG_DEPSTRUCT, PNG_DEPRECATED, PNG_USE_RESULT, PNG_NORETURN, and
+    PNG_ALLOCATED macros to detect deprecated direct access to the
+    png_struct or info_struct members and other deprecated usage in
+    applications (John Bowler).
+  Updated scripts/makefile* to add "-DPNG_CONFIGURE_LIBPNG" to CFLAGS,
+    to prevent warnings about direct access to png structs by libpng
+    functions while building libpng.  They need to be tested, especially
+    those using compilers other than gcc.
+  Updated projects/visualc6 and visualc71 with "/d PNG_CONFIGURE_LIBPNG".
+    They should work but still need to be updated to remove
+    references to pnggccrd.c or pngvcrd.c and ASM building.
+  Added README.txt to the beos, cbuilder5, netware, and xcode projects warning
+    that they need to be updated, to remove references to pnggccrd.c and
+    pngvcrd.c and to depend on pngpriv.h
+  Removed three direct references to read_info_ptr members in pngtest.c
+    that were detected by the new PNG_DEPSTRUCT macro.
+  Moved the png_debug macro definitions and the png_read_destroy(),
+    png_write_destroy() and png_far_to_near() prototypes from png.h
+    to pngpriv.h (John Bowler)
+  Moved the synopsis lines for png_read_destroy(), png_write_destroy()
+    png_debug(), png_debug1(), and png_debug2() from libpng.3 to libpngpf.3.
+
+Version 1.4.0beta94 [November 9, 2009]
+  Removed the obsolete, unused pnggccrd.c and pngvcrd.c files.
+  Updated CMakeLists.txt to add "-DPNG_CONFIGURE_LIBPNG" to the definitions.
+  Removed dependency of pngtest.o on pngpriv.h in the makefiles.
+  Only #define PNG_DEPSTRUCT, etc. in pngconf.h if not already defined.
+
+Version 1.4.0beta95 [November 10, 2009]
+  Changed png_check_sig() to !png_sig_cmp() in contrib programs.
+  Added -DPNG_CONFIGURE_LIBPNG to contrib/pngminm/*/makefile
+  Changed png_check_sig() to !png_sig_cmp() in contrib programs.
+  Corrected the png_get_IHDR() call in contrib/gregbook/readpng2.c
+  Changed pngminim/*/gather.sh to stop trying to remove pnggccrd.c and pngvcrd.c
+  Added dependency on pngpriv.h in contrib/pngminim/*/makefile
+
+Version 1.4.0beta96 [November 12, 2009]
+  Renamed scripts/makefile.wce to scripts/makefile.cegcc
+  Revised Makefile.am to use libpng.sys while building libpng.so
+    so that only PNG_EXPORT functions are exported.
+  Removed the deprecated png_check_sig() function/macro.
+  Removed recently removed function names from scripts/*.def
+  Revised pngtest.png to put chunks in the same order written by pngtest
+    (evidently the same change made in libpng-1.0beta54 was lost).
+  Added PNG_PRIVATE macro definition in pngconf.h for possible future use.
+
+Version 1.4.0beta97 [November 13, 2009]
+  Restored pngtest.png to the libpng-1.4.0beta7 version.
+  Removed projects/beos and netware.txt; no one seems to be supporting them.
+  Revised Makefile.in
+
+Version 1.4.0beta98 [November 13, 2009]
+  Added the "xcode" project to zip distributions,
+  Fixed a typo in scripts/pngwin.def introduced in beta97.
+
+Version 1.4.0beta99 [November 14, 2009]
+  Moved libpng-config.in and libpng.pc-configure.in out of the scripts
+    directory, to libpng-config.in and libpng-pc.in, respectively, and
+    modified Makefile.am and configure.ac accordingly.  Now "configure"
+    needs nothing from the "scripts" directory.
+  Avoid redefining PNG_CONST in pngconf.h
+
+Version 1.4.0beta100 [November 14, 2009]
+  Removed ASM builds from projects/visualc6 and projects/visualc71
+  Removed scripts/makefile.nommx and makefile.vcawin32
+  Revised CMakeLists.txt to account for new location of libpng-config.in
+    and libpng-pc.in
+  Updated INSTALL to reflect removal and relocation of files.
+
+Version 1.4.0beta101 [November 14, 2009]
+  Restored the binary files (*.jpg, *.png, some project files) that were
+    accidentally deleted from the zip and 7z distributions when the xcode
+    project was added.
+
+Version 1.4.0beta102 [November 18, 2009]
+  Added libpng-config.in and libpng-pc.in to the zip and 7z distributions.
+  Fixed a typo in projects/visualc6/pngtest.dsp, introduced in beta100.
+  Moved descriptions of makefiles and other scripts out of INSTALL into
+    scripts/README.txt
+  Updated the copyright year in scripts/pngwin.rc from 2006 to 2009.
+
+Version 1.4.0beta103 [November 21, 2009]
+  Removed obsolete comments about ASM from projects/visualc71/README_zlib.txt
+  Align row_buf on 16-byte boundary in memory.
+  Restored the PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED guard around the call
+    to png_flush() after png_write_IEND().  See 1.4.0beta32, 1.4.0beta50
+    changes above and 1.2.30, 1.2.30rc01 and rc03 in 1.2.41 CHANGES.  Someone
+    needs this feature.
+  Make the 'png_jmpbuf' macro expand to a call that records the correct
+    longjmp function as well as returning a pointer to the setjmp
+    jmp_buf buffer, and marked direct access to jmpbuf 'deprecated'.
+    (John Bowler)
+
+Version 1.4.0beta104 [November 22, 2009]
+  Removed png_longjmp_ptr from scripts/*.def and libpng.3
+  Rebuilt configure scripts with autoconf-2.65
+
+Version 1.4.0beta105 [November 25, 2009]
+  Use fast integer PNG_DIVIDE_BY_255() or PNG_DIVIDE_BY_65535()
+    to accomplish alpha premultiplication when
+    PNG_READ_COMPOSITE_NODIV_SUPPORTED is defined.
+  Changed "/255" to "/255.0" in background calculations to make it clear
+    that the 255 is used as a double.
+
+Version 1.4.0beta106 [November 27, 2009]
+  Removed premultiplied alpha feature.
+
+Version 1.4.0beta107 [December 4, 2009]
+  Updated README
+  Added "#define PNG_NO_PEDANTIC_WARNINGS" in the libpng source files.
+  Removed "-DPNG_CONFIGURE_LIBPNG" from the makefiles and projects.
+  Revised scripts/makefile.netbsd, makefile.openbsd, and makefile.sco
+    to put png.h and pngconf.h in $prefix/include, like the other scripts,
+    instead of in $prefix/include/libpng.  Also revised makefile.sco
+    to put them in $prefix/include/libpng15 instead of in
+    $prefix/include/libpng/libpng15.
+
+Version 1.4.0beta108 [December 11, 2009]
+  Removed leftover "-DPNG_CONFIGURE_LIBPNG" from contrib/pngminim/*/makefile
+  Relocated png_do_chop() to its original position in pngrtran.c; the
+    change in version 1.2.41beta08 caused transparency to be handled wrong
+    in some 16-bit datastreams (Yusaku Sugai).
+
+Version 1.4.0beta109 [December 13, 2009]
+  Added "bit_depth" parameter to the private png_build_gamma_table() function.
+  Pass bit_depth=8 to png_build_gamma_table() when bit_depth is 16 but the
+    PNG_16_TO_8 transform has been set, to avoid unnecessary build of 16-bit
+    tables.
+
+Version 1.4.0rc02 [December 20, 2009]
+  Declared png_cleanup_needed "volatile" in pngread.c and pngwrite.c
+
+Version 1.4.0rc03 [December 22, 2009]
+  Renamed libpng-pc.in back to libpng.pc.in and revised CMakeLists.txt
+    (revising the change in 1.4.0beta99)
+
+Version 1.4.0rc04 [December 25, 2009]
+  Swapped PNG_UNKNOWN_CHUNKS_SUPPORTED and PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+    in pngset.c to be consistent with other changes in version 1.2.38.
+
+Version 1.4.0rc05 [December 25, 2009]
+  Changed "libpng-pc.in" to "libpng.pc.in" in configure.ac, configure, and
+    Makefile.in to be consistent with changes in libpng-1.4.0rc03
+
+Version 1.4.0rc06 [December 29, 2009]
+  Reverted the gamma_table changes from libpng-1.4.0beta109.
+  Fixed some indentation errors.
+
+Version 1.4.0rc07 [January 1, 2010]
+  Revised libpng*.txt and libpng.3 about 1.2.x->1.4.x differences.
+  Use png_calloc() instead of png_malloc(); png_memset() in pngrutil.c
+  Update copyright year to 2010.
+
+Version 1.4.0rc08 [January 2, 2010]
+  Avoid deprecated references to png_ptr-io_ptr and png_ptr->error_ptr
+    in pngtest.c
+
+Version 1.4.0 [January 3, 2010]
+  No changes.
+
+Version 1.4.1beta01 [January 8, 2010]
+  Updated CMakeLists.txt for consistent indentation and to avoid an
+    unclosed if-statement warning (Philip Lowman).
+  Revised Makefile.am and Makefile.in to remove references to Y2KINFO,
+    KNOWNBUG, and libpng.la (Robert Schwebel).
+  Revised the makefiles to install the same files and symbolic
+    links as configure, except for libpng.la and libpng14.la.
+  Make png_set|get_compression_buffer_size() available even when
+    PNG_WRITE_SUPPORTED is not enabled.
+  Revised Makefile.am and Makefile.in to simplify their maintenance.
+  Revised scripts/makefile.linux to install a link to libpng14.so.14.1
+
+Version 1.4.1beta02 [January 9, 2010]
+  Revised the rest of the makefiles to install a link to libpng14.so.14.1
+
+Version 1.4.1beta03 [January 10, 2010]
+  Removed png_set_premultiply_alpha() from scripts/*.def
+
+Version 1.4.1rc01 [January 16, 2010]
+  No changes.
+
+Version 1.4.1beta04 [January 23, 2010]
+  Revised png_decompress_chunk() to improve speed and memory usage when
+    decoding large chunks.
+  Added png_set|get_chunk_malloc_max() functions.
+
+Version 1.4.1beta05 [January 26, 2010]
+  Relocated "int k" declaration in pngtest.c to minimize its scope.
+
+Version 1.4.1beta06 [January 28, 2010]
+  Revised png_decompress_chunk() to use a two-pass method suggested by
+    John Bowler.
+
+Version 1.4.1beta07 [February 6, 2010]
+  Folded some long lines in the source files.
+  Added defineable PNG_USER_CHUNK_CACHE_MAX, PNG_USER_CHUNK_MALLOC_MAX,
+    and a PNG_USER_LIMITS_SUPPORTED flag.
+  Eliminated use of png_ptr->irowbytes and reused the slot in png_ptr as
+    png_ptr->png_user_chunk_malloc_max.
+  Revised png_push_save_buffer() to do fewer but larger png_malloc() calls.
+
+Version 1.4.1beta08 [February 6, 2010]
+  Minor cleanup and updating of dates and copyright year.
+
+Version 1.5.0beta01 [February 7, 2010]
+  Moved declaration of png_struct into private pngstruct.h and png_info
+    into pnginfo.h
+
+Version 1.4.1beta09 and 1.5.0beta02 [February 7, 2010]
+  Reverted to original png_push_save_buffer() code.
+
+Version 1.4.1beta10 and 1.5.0beta03 [February 8, 2010]
+  Return allocated "old_buffer" in png_push_save_buffer() before
+    calling png_error(), to avoid a potential memory leak.
+  Updated configure script to use SO number 15.
+
+Version 1.5.0beta04 [February 9, 2010]
+  Removed malformed "incomplete struct declaration" of png_info from png.h
+
+Version 1.5.0beta05 [February 12, 2010]
+  Removed PNG_DEPSTRUCT markup in pngstruct.h and pnginfo.h, and undid the
+    linewrapping that it entailed.
+  Revised comments in pngstruct.h and pnginfo.h and added pointers to
+    the libpng license.
+  Changed PNG_INTERNAL to PNG_EXPOSE_INTERNAL_STRUCTURES
+  Removed the cbuilder5 project, which has not been updated to 1.4.0.
+
+Version 1.4.1beta12 and 1.5.0beta06 [February 14, 2010]
+  Fixed type declaration of png_get_chunk_malloc_max() in pngget.c (Daisuke
+    Nishikawa)
+
+Version 1.5.0beta07 [omitted]
+
+Version 1.5.0beta08 [February 19, 2010]
+  Changed #ifdef PNG_NO_STDIO_SUPPORTED to #ifdef PNG_NO_CONSOLE_IO_SUPPORTED
+    wherever png_snprintf() is used to construct error and warning messages.
+  Noted in scripts/makefile.mingw that it expects to be run under MSYS.
+  Removed obsolete unused MMX-querying support from contrib/gregbook
+  Added exported png_longjmp() function.
+  Removed the AIX redefinition of jmpbuf in png.h
+  Added -D_ALLSOURCE in configure.ac, makefile.aix, and CMakeLists.txt
+    when building on AIX.
+
+Version 1.5.0beta09 [February 19, 2010]
+  Removed -D_ALLSOURCE from configure.ac, makefile.aix, and CMakeLists.txt.
+  Changed the name of png_ptr->jmpbuf to png_ptr->png_jmpbuf in pngstruct.h
+
+Version 1.5.0beta10 [February 25, 2010]
+  Removed unused gzio.c from contrib/pngminim gather and makefile scripts
+  Removed replacement error handlers from contrib/gregbook.  Because of
+    the new png_longjmp() function they are no longer needed.
+
+Version 1.5.0beta11 [March 6, 2010]
+  Removed checking for already-included setjmp.h from pngconf.h
+  Fixed inconsistent indentations and made numerous cosmetic changes.
+  Revised the "SEE ALSO" style of libpng.3, libpngpf.3, and png.5
+
+Version 1.5.0beta12 [March 9, 2010]
+  Moved "#include png.h" inside pngpriv.h and removed "#include png.h" from
+    the source files, along with "#define PNG_EXPOSE_INTERNAL_STRUCTURES"
+    and "#define PNG_NO_PEDANTIC_WARNINGS" (John Bowler).
+  Created new pngdebug.h and moved debug definitions there.
+
+Version 1.5.0beta13 [March 10, 2010]
+  Protect pngstruct.h, pnginfo.h, and pngdebug.h from being included twice.
+  Revise the "#ifdef" blocks in png_inflate() so it will compile when neither
+    PNG_USER_CHUNK_MALLOC_MAX nor PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
+    is defined.
+  Removed unused png_measure_compressed_chunk() from pngpriv.h and libpngpf.3
+  Moved the 'config.h' support from pngconf.h to pngpriv.h
+  Removed PNGAPI from the png_longjmp_ptr typedef.
+  Eliminated dependence of pngtest.c on the private pngdebug.h file.
+  Make all png_debug macros into *unterminated* statements or
+    expressions (i.e. a trailing ';' must always be added) and correct
+    the format statements in various png_debug messages.
+
+Version 1.5.0beta14 [March 14, 2010]
+  Removed direct access to png_ptr->io_ptr from the Windows code in pngtest.c
+  Revised Makefile.am to account for recent additions and replacements.
+  Corrected CE and OS/2 DEF files (scripts/png*def) for symbols removed and
+    added ordinal numbers to the Windows DEF file and corrected the duplicated
+    ordinal numbers on CE symbols that are commented out.
+  Added back in export symbols that can be present in the Windows build but
+    are disabled by default.
+  PNG_EXPORT changed to include an 'ordinal' field for DEF file generation.
+    PNG_CALLBACK added to make callback definitions uniform.  PNGAPI split
+    into PNGCAPI (base C form), PNGAPI (exports) and PNGCBAPI (callbacks),
+    and appropriate changes made to all files.  Cygwin builds re-hinged to
+    allow procedure call standard changes and to remove the need for the DEF
+    file (fixes build on Cygwin).
+  Enabled 'attribute' warnings that are relevant to library APIs and callbacks.
+  Changed rules for generation of the various symbol files and added a new
+    rule for a DEF file (which is also added to the distribution).
+  Updated the symbol file generation to stop it adding spurious spaces
+    to EOL (coming from preprocessor macro expansion).  Added a facility
+    to join tokens in the output and rewrite *.dfn to use this.
+  Eliminated scripts/*.def in favor of libpng.def; updated projects/visualc71
+    and removed scripts/makefile.cygwin.
+  Made PNG_BUILD_DLL safe: it can be set whenever a DLL is being built.
+  Removed the include of sys/types.h - apparently unnecessary now on the
+    platforms on which it happened (all but Mac OS and RISC OS).
+  Moved the Mac OS test into pngpriv.h (the only place it is used.)
+
+Version 1.5.0beta15 [March 17, 2010]
+  Added symbols.chk target to Makefile.am to validate the symbols in png.h
+    against the new DEF file scripts/symbols.def.
+  Changed the default DEF file back to pngwin.def.
+  Removed makefile.mingw.
+  Eliminated PNG_NO_EXTERN and PNG_ALL_EXTERN
+
+Version 1.5.0beta16 [April 1, 2010]
+  Make png_text_struct independent of PNG_iTXt_SUPPORTED, so that
+    fields are initialized in all configurations.  The READ/WRITE
+    macros (PNG_(READ|WRITE)_iTXt_SUPPORTED) still function as
+    before to disable code to actually read or write iTXt chunks
+    and iTXt_SUPPORTED can be used to detect presence of either
+    read or write support (but it is probably better to check for
+    the one actually required - read or write.)
+  Combined multiple png_warning() calls for a single error.
+  Restored the macro definition of png_check_sig().
+
+Version 1.5.0beta17 [April 17, 2010]
+  Added some "(long)" typecasts to printf calls in png_handle_cHRM().
+  Documented the fact that png_set_dither() was disabled since libpng-1.4.0.
+  Reenabled png_set_dither() but renamed it to png_set_quantize() to reflect
+    more accurately what it actually does.  At the same time, renamed
+    the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros to
+    PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS.
+  Added some "(long)" typecasts to printf calls in png_handle_cHRM().
+  Freeze build-time only configuration in the build.
+    In all prior versions of libpng most configuration options
+    controlled by compiler #defines had to be repeated by the
+    application code that used libpng.  This patch changes this
+    so that compilation options that can only be changed at build
+    time are frozen in the build.  Options that are compiler
+    dependent (and those that are system dependent) are evaluated
+    each time - pngconf.h holds these.  Options that can be changed
+    per-file in the application are in png.h.  Frozen options are
+    in the new installed header file pnglibconf.h (John Bowler)
+  Removed the xcode project because it has not been updated to work
+    with libpng-1.5.0.
+  Removed the ability to include optional pngusr.h
+
+Version 1.5.0beta18 [April 17, 2010]
+  Restored the ability to include optional pngusr.h
+  Moved replacements for png_error() and png_warning() from the
+    contrib/pngminim project to pngerror.c, for use when warnings or
+    errors are disabled via PNG_NO_WARN or PNG_NO_ERROR_TEXT, to avoid
+    storing unneeded error/warning text.
+  Updated contrib/pngminim project to work with the new pnglibconf.h
+  Added some PNG_NO_* defines to contrib/pngminim/*/pngusr.h to save space.
+
+Version 1.5.0beta19 [April 24, 2010]
+  Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the functions
+    to read and write ints to be disabled independently of PNG_USE_READ_MACROS,
+    which allows libpng to be built with the functions even though the default
+    is to use the macros - this allows applications to choose at app build
+    time whether or not to use macros (previously impossible because the
+    functions weren't in the default build.)
+  Changed Windows calling convention back to __cdecl for API functions.
+    For Windows/x86 platforms only:
+      __stdcall is no longer needed for Visual Basic, so libpng-1.5.0 uses
+      __cdecl throughout (both API functions and callbacks) on Windows/x86
+      platforms.
+  Replaced visualc6 and visualc71 projects with new vstudio project
+  Relaxed the overly-restrictive permissions of some files.
+
+Version 1.5.0beta20 [April 24, 2010]
+  Relaxed more overly-restrictive permissions of some files.
+
+Version 1.5.0beta21 [April 27, 2010]
+  Removed some unwanted binary bytes and changed CRLF to NEWLINE in the new
+    vstudio project files, and some trivial editing of some files in the
+    scripts directory.
+  Set PNG_NO_READ_BGR, PNG_NO_IO_STATE, and PNG_NO_TIME_RFC1123 in
+    contrib/pngminim/decoder/pngusr.h to make a smaller decoder application.
+
+Version 1.5.0beta22 [April 28, 2010]
+  Fixed dependencies of GET_INT_32 - it does not require READ_INT_FUNCTIONS
+    because it has a macro equivalent.
+  Improved the options.awk script; added an "everything off" option.
+  Revised contrib/pngminim to use the "everything off" option in pngusr.dfa.
+
+Version 1.5.0beta23 [April 29, 2010]
+  Corrected PNG_REMOVED macro to take five arguments.
+    The macro was documented with two arguments (name,ordinal), however
+    the symbol checking .dfn files assumed five arguments.  The five
+    argument form seems more useful so it is changed to that.
+  Corrected PNG_UNKNOWN_CHUNKS_SUPPORTED to PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+    in gregbook/readpng2.c
+  Corrected protection of png_get_user_transform_ptr. The API declaration in
+    png.h is removed if both READ and WRITE USER_TRANSFORM are turned off
+    but was left defined in pngtrans.c
+  Added logunsupported=1 to cause pnglibconf.h to document disabled options.
+    This makes the installed pnglibconf.h more readable but causes no
+    other change.  The intention is that users of libpng will find it
+    easier to understand if an API they need is missing.
+  Include png_reset_zstream() in png.c only when PNG_READ_SUPPORTED is defined.
+  Removed dummy_inflate.c from contrib/pngminim/encoder
+  Removed contrib/pngminim/*/gather.sh; gathering is now done in the makefile.
+
+Version 1.5.0beta24 [May 7, 2010]
+  Use bitwise "&" instead of arithmetic mod in pngrutil.c calculation of the
+    offset of the png_ptr->rowbuf pointer into png_ptr->big_row_buf.
+  Added more blank lines for readability.
+
+Version 1.5.0beta25 [June 18, 2010]
+  In pngpread.c: png_push_have_row() add check for new_row > height
+  Removed the now-redundant check for out-of-bounds new_row from example.c
+
+Version 1.5.0beta26 [June 18, 2010]
+  In pngpread.c: png_push_process_row() add check for too many rows.
+
+Version 1.5.0beta27 [June 18, 2010]
+  Removed the check added in beta25 as it is now redundant.
+
+Version 1.5.0beta28 [June 20, 2010]
+  Rewrote png_process_IDAT_data to consistently treat extra data as warnings
+    and handle end conditions more cleanly.
+  Removed the new (beta26) check in png_push_process_row().
+
+Version 1.5.0beta29 [June 21, 2010]
+  Revised scripts/options.awk to work on Sunos (but still doesn't work)
+  Added comment to options.awk and contrib/pngminim/*/makefile to try nawk.
+
+Version 1.5.0beta30 [June 22, 2010]
+  Stop memory leak when reading a malformed sCAL chunk.
+
+Version 1.5.0beta31 [June 26, 2010]
+  Revised pngpread.c patch of beta28 to avoid an endless loop.
+  Removed some trailing blanks.
+
+Version 1.5.0beta32 [June 26, 2010]
+  Removed leftover scripts/options.patch and scripts/options.rej
+
+Version 1.5.0beta33 [July 6, 3010]
+  Made FIXED and FLOATING options consistent in the APIs they enable and
+    disable.  Corrected scripts/options.awk to handle both command line
+    options and options specified in the .dfa files.
+  Changed char *msg to PNG_CONST char *msg in pngrutil.c
+  Make png_set_sRGB_gAMA_and_cHRM set values using either the fixed or
+    floating point APIs, but not both.
+  Reversed patch to remove error handler when the jmp_buf is stored in the
+    main program structure, not the png_struct.
+    The error handler is needed because the default handler in libpng will
+    always use the jmp_buf in the library control structure; this is never
+    set.  The gregbook code is a useful example because, even though it
+    uses setjmp/longjmp, it shows how error handling can be implemented
+    using control mechanisms not directly supported by libpng.  The
+    technique will work correctly with mechanisms such as Microsoft
+    Structure Exceptions or C++ exceptions (compiler willing - note that gcc
+    does not by default support interworking of C and C++ error handling.)
+  Reverted changes to call png_longjmp in contrib/gregbook where it is not
+    appropriate.  If mainprog->jmpbuf is used by setjmp, then png_longjmp
+    cannot be used.
+  Changed "extern PNG_EXPORT" to "PNG_EXPORT" in png.h (Jan Nijtmans)
+  Changed "extern" to "PNG_EXTERN" in pngpriv.h (except for the 'extern "C" {')
+
+Version 1.5.0beta34 [July 12, 2010]
+  Put #ifndef PNG_EXTERN, #endif around the define PNG_EXTERN in pngpriv.h
+
+Version 1.5.0beta35 [July 24, 2010]
+  Removed some newly-added TAB characters.
+  Added -DNO_PNG_SNPRINTF to CFLAGS in scripts/makefile.dj2
+  Moved the definition of png_snprintf() outside of the enclosing
+    #ifdef blocks in pngconf.h
+
+Version 1.5.0beta36 [July 29, 2010]
+  Patches by John Bowler:
+  Fixed point APIs are now supported throughout (no missing APIs).
+  Internal fixed point arithmetic support exists for all internal floating
+    point operations.
+  sCAL validates the floating point strings it is passed.
+  Safe, albeit rudimentary, Watcom support is provided by PNG_API_RULE==2
+  Two new APIs exist to get the number of passes without turning on the
+    PNG_INTERLACE transform and to get the number of rows in the current
+    pass.
+  A new test program, pngvalid.c, validates the gamma code.
+  Errors in the 16-bit gamma correction (overflows) have been corrected.
+  cHRM chunk testing is done consistently (previously the floating point
+    API bypassed it, because the test really didn't work on FP, now the test
+    is performed on the actual values to be stored in the PNG file so it
+    works in the FP case too.)
+  Most floating point APIs now simply call the fixed point APIs after
+    converting the values to the fixed point form used in the PNG file.
+  The standard headers no longer include zlib.h, which is currently only
+    required for pngstruct.h and can therefore be internal.
+  Revised png_get_int_32 to undo the PNG two's complement representation of
+    negative numbers.
+
+Version 1.5.0beta37 [July 30, 2010]
+  Added a typecast in png_get_int_32() in png.h and pngrutil.h to avoid
+    a compiler warning.
+  Replaced oFFs 0,0 with oFFs -10,20 in pngtest.png
+
+Version 1.5.0beta38 [July 31, 2010]
+  Implemented remaining "_fixed" functions.
+  Corrected a number of recently introduced warnings mostly resulting from
+    safe but uncast assignments to shorter integers.  Also added a zlib
+    VStudio release library project because the latest zlib Official Windows
+    build does not include such a thing.
+  Revised png_get_int_16() to be similar to png_get_int_32().
+  Restored projects/visualc71.
+
+Version 1.5.0beta39 [August 2, 2010]
+  VisualC/GCC warning fixes, VisualC build fixes
+  The changes include support for function attributes in VC in addition to
+    those already present in GCC - necessary because without these some
+    warnings are unavoidable.  Fixes include signed/unsigned fixes in
+    pngvalid and checks with gcc -Wall -Wextra -Wunused.
+  VC requires function attributes on function definitions as well as
+    declarations, PNG_FUNCTION has been added to enable this and the
+    relevant function definitions changed.
+
+Version 1.5.0beta40 [August 6, 2010]
+  Correct use of _WINDOWS_ in pngconf.h
+  Removed png_mem_ #defines; they are no longer used.
+  Added the sRGB chunk to pngtest.png
+
+Version 1.5.0beta41 [August 11, 2010]
+  Added the cHRM chunk to pngtest.png
+  Don't try to use version-script with cygwin/mingw.
+  Revised contrib/gregbook to work under cygwin/mingw.
+
+Version 1.5.0beta42 [August 18, 2010]
+  Add .dll.a to the list of extensions to be symlinked by Makefile.am (Yaakov)
+  Made all API functions that have const arguments and constant string
+    literal pointers declare them (John Bowler).
+
+Version 1.5.0beta43 [August 20, 2010]
+  Removed spurious tabs, shorten long lines (no source change)
+    Also added scripts/chkfmt to validate the format of all the files that can
+    reasonably be validated (it is suggested to run "make distclean" before
+    checking, because some machine generated files have long lines.)
+  Reformatted the CHANGES file to be more consistent throughout.
+  Made changes to address various issues identified by GCC, mostly
+    signed/unsigned and shortening problems on assignment but also a few
+    difficult to optimize (for GCC) loops.
+  Fixed non-GCC fixed point builds.  In png.c a declaration was misplaced
+    in an earlier update.  Fixed to declare the auto variables at the head.
+  Use cexcept.h in pngvalid.c.
+
+Version 1.5.0beta44 [August 24, 2010]
+  Updated CMakeLists.txt to use CMAKE_INSTALL_LIBDIR variable; useful for
+    installing libpng in /usr/lib64 (Funda Wang).
+  Revised CMakeLists.txt to put the man pages in share/man/man* not man/man*
+  Revised CMakeLists.txt to make symlinks instead of copies when installing.
+  Changed PNG_LIB_NAME from pngNN to libpngNN in CMakeLists.txt (Philip Lowman)
+  Implemented memory checks within pngvalid
+  Reformatted/rearranged pngvalid.c to assist use of progressive reader.
+  Check interlaced images in pngvalid
+  Clarified pngusr.h comments in pnglibconf.dfa
+  Simplified the pngvalid error-handling code now that cexcept.h is in place.
+  Implemented progressive reader in pngvalid.c for standard tests
+  Implemented progressive read in pngvalid.c gamma tests
+  Turn on progressive reader in pngvalid.c by default and tidy code.
+
+Version 1.5.0beta45 [August 26, 2010]
+  Added an explicit make step to projects/vstudio for pnglibconf.h
+    Also corrected zlib.vcxproj into which Visual Studio had introduced
+    what it calls an "authoring error".  The change to make pnglibconf.h
+    simply copies the file; in the future it may actually generate the
+    file from scripts/pnglibconf.dfa as the other build systems do.
+  Changed pngvalid to work when floating point APIs are disabled
+  Renamed the prebuilt scripts/pnglibconf.h to scripts/pnglibconf.h.prebuilt
+  Supply default values for PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX
+    in pngpriv.h in case the user neglected to define them in their pngusr.h
+
+Version 1.5.0beta46 [August 28, 2010]
+  Added new private header files to libpng_sources in CMakeLists.txt
+  Added PNG_READ_16BIT, PNG_WRITE_16BIT, and PNG_16BIT options.
+  Added reference to scripts/pnglibconf.h.prebuilt in the visualc71 project.
+
+Version 1.5.0beta47 [September 11, 2010]
+  Fixed a number of problems with 64-bit compilation reported by Visual
+    Studio 2010 (John Bowler).
+
+Version 1.5.0beta48 [October 4, 2010]
+  Updated CMakeLists.txt (Philip Lowman).
+  Revised autogen.sh to recognize and use $AUTOCONF, $AUTOMAKE, $AUTOHEADER,
+    $AUTOPOINT, $ACLOCAL and $LIBTOOLIZE
+  Fixed problem with symbols creation in Makefile.am which was assuming that
+    all versions of ccp write to standard output by default (Martin Banky). The
+    bug was introduced in libpng-1.2.9beta5.
+  Removed unused mkinstalldirs.
+
+Version 1.5.0beta49 [October 8, 2010]
+  Undid Makefile.am revision of 1.5.0beta48.
+
+Version 1.5.0beta50 [October 14, 2010]
+  Revised Makefile.in to account for mkinstalldirs being removed.
+  Added some "(unsigned long)" typecasts in printf statements in pngvalid.c.
+  Suppressed a compiler warning in png_handle_sPLT().
+  Check for out-of-range text compression mode in png_set_text().
+
+Version 1.5.0beta51 [October 15, 2010]
+  Changed embedded dates to "(PENDING RELEASE) in beta releases (and future
+    rc releases) to minimize the difference between releases.
+
+Version 1.5.0beta52 [October 16, 2010]
+  Restored some of the embedded dates (in png.h, png.c, documentation, etc.)
+
+Version 1.5.0beta53 [October 18, 2010]
+  Updated INSTALL to mention using "make maintainer-clean" and to remove
+    obsolete statement about a custom ltmain.sh
+  Disabled "color-tests" by default in Makefile.am so it will work with
+    automake versions earlier than 1.11.1
+  Use document name "libpng-manual.txt" instead of "libpng-<version>.txt"
+    to simplify version differences.
+  Removed obsolete remarks about setjmp handling from INSTALL.
+  Revised and renamed the typedef in png.h and png.c that was designed
+    to catch library and header mismatch.
+
+Version 1.5.0beta54 [November 10, 2010]
+  Require 48 bytes, not 64 bytes, for big_row_buf in overflow checks.
+  Used a consistent structure for the pngget.c functions.
+
+Version 1.5.0beta55 [November 21, 2010]
+  Revised png_get_uint_32, png_get_int_32, png_get_uint_16 (Cosmin)
+  Moved reading of file signature into png_read_sig (Cosmin)
+  Fixed atomicity of chunk header serialization (Cosmin)
+  Added test for io_state in pngtest.c (Cosmin)
+  Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts.
+  Changes to remove gcc warnings (John Bowler)
+    Certain optional gcc warning flags resulted in warnings in libpng code.
+    With these changes only -Wconversion and -Wcast-qual cannot be turned on.
+    Changes are trivial rearrangements of code.  -Wconversion is not possible
+    for pngrutil.c (because of the widespread use of += et al on variables
+    smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
+    with pngwio.c and pngwutil.c because the 'write' callback and zlib
+    compression both fail to declare their input buffers with 'const'.
+
+Version 1.5.0beta56 [December 7, 2010]
+  Added the private PNG_UNUSED() macro definition in pngpriv.h.
+  Added some commentary about PNG_EXPORT in png.h and pngconf.h
+  Revised PNG_EXPORT() macro and added PNG_EXPORTA() macro, with the
+    objective of simplifying and improving the cosmetic appearance of png.h.
+  Fixed some incorrect "=" macro names in pnglibconf.dfa
+  Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt
+
+Version 1.5.0beta57 [December 9, 2010]
+  Documented the pngvalid gamma error summary with additional comments and
+    print statements.
+  Improved missing symbol handling in checksym.awk; symbols missing in both
+    the old and new files can now be optionally ignored, treated as errors
+    or warnings.
+  Removed references to pngvcrd.c and pnggccrd.c from the vstudio project.
+  Updated "libpng14" to "libpng15" in the visualc71 project.
+  Enabled the strip16 tests in pngvalid.`
+  Don't display test results (except PASS/FAIL) when running "make test".
+    Instead put them in pngtest-log.txt
+  Added "--with-zprefix=<string>" to configure.ac
+  Updated the prebuilt configuration files to autoconf version 2.68
+
+Version 1.5.0beta58 [December 19, 2010]
+  Fixed interlace image handling and add test cases (John Bowler)
+  Fixed the clean rule in Makefile.am to remove pngtest-log.txt
+  Made minor changes to work around warnings in gcc 3.4
+
+Version 1.5.0rc01 [December 27, 2010]
+  No changes.
+
+Version 1.5.0rc02 [December 27, 2010]
+  Eliminated references to the scripts/*.def files in project/visualc71.
+
+Version 1.5.0rc03 [December 28, 2010]
+  Eliminated scripts/*.def and revised Makefile.am accordingly
+
+Version 1.5.0rc04 [December 29, 2010]
+  Fixed bug in background transformation handling in pngrtran.c (it was
+    looking for the flag in png_ptr->transformations instead of in
+    png_ptr->flags) (David Raymond).
+
+Version 1.5.0rc05 [December 31, 2010]
+  Fixed typo in a comment in CMakeLists.txt (libpng14 => libpng15) (Cosmin)
+
+Version 1.5.0rc06 [January 4, 2011]
+  Changed the new configure option "zprefix=string" to "zlib-prefix=string"
+
+Version 1.5.0rc07 [January 4, 2011]
+  Updated copyright year.
+
+Version 1.5.0 [January 6, 2011]
+  No changes.
+
+version 1.5.1beta01 [January 8, 2011]
+  Added description of png_set_crc_action() to the manual.
+  Added a note in the manual that the type of the iCCP profile was changed
+    from png_charpp to png_bytepp in png_get_iCCP().  This change happened
+    in version 1.5.0beta36 but is not noted in the CHANGES.  Similarly,
+    it was changed from png_charpp to png_const_bytepp in png_set_iCCP().
+  Ensure that png_rgb_to_gray ignores palette mapped images, if libpng
+    internally happens to call it with one, and fixed a failure to handle
+    palette mapped images correctly.  This fixes CVE-2690.
+
+Version 1.5.1beta02 [January 14, 2011]
+  Fixed a bug in handling of interlaced images (bero at arklinux.org).
+  Updated CMakeLists.txt (Clifford Yapp)
+
+Version 1.5.1beta03 [January 14, 2011]
+  Fixed typecasting of some png_debug() statements (Cosmin)
+
+Version 1.5.1beta04 [January 16, 2011]
+  Updated documentation of png_set|get_tRNS() (Thomas Klausner).
+  Mentioned in the documentation that applications must #include "zlib.h"
+    if they need access to anything in zlib.h, and that a number of
+    macros such as png_memset() are no longer accessible by applications.
+  Corrected pngvalid gamma test "sample" function to access all of the color
+    samples of each pixel, instead of sampling the red channel three times.
+  Prefixed variable names index, div, exp, gamma with "png_" to avoid "shadow"
+    warnings, and (mistakenly) changed png_exp() to exp().
+
+Version 1.5.1beta05 [January 16, 2011]
+  Changed variable names png_index, png_div, png_exp, and png_gamma to
+    char_index, divisor, exp_b10, and gamma_val, respectively, and
+    changed exp() back to png_exp().
+
+Version 1.5.1beta06 [January 20, 2011]
+  Prevent png_push_crc_skip() from hanging while reading an unknown chunk
+    or an over-large compressed zTXt chunk with the progressive reader.
+  Eliminated more GCC "shadow" warnings.
+  Revised png_fixed() in png.c to avoid compiler warning about reaching the
+    end without returning anything.
+
+Version 1.5.1beta07 [January 22, 2011]
+  In the manual, describe the png_get_IHDR() arguments in the correct order.
+  Added const_png_structp and const_png_infop types, and used them in
+    prototypes for most png_get_*() functions.
+
+Version 1.5.1beta08 [January 23, 2011]
+  Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name()
+  Added synopses for the IO_STATE functions and other missing synopses
+    to the manual. Removed the synopses from libpngpf.3 because they
+    were out of date and no longer useful.  Better information can be
+    obtained by reading the prototypes and comments in pngpriv.h
+  Attempted to fix cpp on Solaris with S. Studio 12 cc, fix build
+    Added a make macro DFNCPP that is a CPP that will accept the tokens in
+    a .dfn file and adds configure stuff to test for such a CPP.  ./configure
+    should fail if one is not available.
+  Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace.
+  Added png_get_current_row_number and png_get_current_pass_number for the
+    benefit of the user transform callback.
+  Added png_process_data_pause and png_process_data_skip for the benefit of
+    progressive readers that need to stop data processing or want to optimize
+    skipping of unread data (e.g., if the reader marks a chunk to be skipped.)
+
+Version 1.5.1beta09 [January 24, 2011]
+  Enhanced pngvalid, corrected an error in gray_to_rgb, corrected doc error.
+    pngvalid contains tests of transforms, which tests are currently disabled
+    because they are incompletely tested.  gray_to_rgb was failing to expand
+    the bit depth for smaller bit depth images; this seems to be a long
+    standing error and resulted, apparently, in invalid output
+    (CVE-2011-0408, CERT VU#643140).  The documentation did not accurately
+    describe what libpng really does when converting RGB to gray.
+
+Version 1.5.1beta10 [January 27, 2010]
+  Fixed incorrect examples of callback prototypes in the manual, that were
+    introduced in libpng-1.0.0.
+  In addition the order of the png_get_uint macros with respect to the
+    relevant function definitions has been reversed.  This helps the
+    preprocessing of the symbol files be more robust.  Furthermore, the
+    symbol file preprocessing now uses -DPNG_NO_USE_READ_MACROS even when
+    the library may actually be built with PNG_USE_READ_MACROS; this stops
+    the read macros interfering with the symbol file format.
+  Made the manual, synopses, and function prototypes use the function
+    argument names file_gamma, int_file_gamma, and srgb_intent consistently.
+
+Version 1.5.1beta11 [January 28, 2011]
+  Changed PNG_UNUSED from "param=param;" to "{if(param){}}".
+  Corrected local variable type in new API png_process_data_skip()
+    The type was self-evidently incorrect but only causes problems on 64-bit
+    architectures.
+  Added transform tests to pngvalid and simplified the arguments.
+
+Version 1.5.1rc01 [January 29, 2011]
+  No changes.
+
+Version 1.5.1rc02 [January 31, 2011]
+  Added a request in the manual that applications do not use "png_" or
+    "PNG_" to begin any of their own symbols.
+  Changed PNG_UNUSED to "(void)param;" and updated the commentary in pngpriv.h
+
+Version 1.5.1 [February 3, 2011]
+  No changes.
+
+Version 1.5.2beta01 [February 13, 2011]
+  More -Wshadow fixes for older gcc compilers.  Older gcc versions apparently
+    check formal parameters names in function declarations (as well as
+    definitions) to see if they match a name in the global namespace.
+  Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the
+    old VisualC++ preprocessor.
+  Turned on interlace handling in png_read_png().
+  Fixed gcc pedantic warnings.
+  Handle longjmp in Cygwin.
+  Fixed png_get_current_row_number() in the interlaced case.
+  Cleaned up ALPHA flags and transformations.
+  Implemented expansion to 16 bits.
+
+Version 1.5.2beta02 [February 19, 2011]
+  Fixed mistake in the descriptions of user read_transform and write_transform
+    function prototypes in the manual.  The row_info struct is png_row_infop.
+  Reverted png_get_current_row_number() to previous (1.5.2beta01) behavior.
+  Corrected png_get_current_row_number documentation
+  Fixed the read/write row callback documentation.
+    This documents the current behavior, where the callback is called after
+    every row with information pertaining to the next row.
+
+Version 1.5.2beta03 [March 3, 2011]
+  Fixed scripts/makefile.vcwin32
+  Updated contrib/pngsuite/README to add the word "modify".
+  Define PNG_ALLOCATED to blank when _MSC_VER<1300.
+
+Version 1.5.2rc01 [March 19, 2011]
+  Define remaining attributes to blank when MSC_VER<1300.
+  ifdef out mask arrays in pngread.c when interlacing is not supported.
+
+Version 1.5.2rc02 [March 22, 2011]
+  Added a hint to try CPP=/bin/cpp if "cpp -E" fails in scripts/pnglibconf.mak
+    and in contrib/pngminim/*/makefile, eg., on SunOS 5.10, and removed "strip"
+    from the makefiles.
+  Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail
+    to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill)
+
+Version 1.5.2rc03 [March 24, 2011]
+  Don't include standard header files in png.h while building the symbol table,
+    to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro).
+
+Version 1.5.2 [March 31, 2011]
+  No changes.
+
+Version 1.5.3beta01 [April 1, 2011]
+  Re-initialize the zlib compressor before compressing non-IDAT chunks.
+  Added API functions (png_set_text_compression_level() and four others) to
+    set parameters for zlib compression of non-IDAT chunks.
+
+Version 1.5.3beta02 [April 3, 2011]
+  Updated scripts/symbols.def with new API functions.
+  Only compile the new zlib re-initializing code when text or iCCP is
+    supported, using PNG_WRITE_COMPRESSED_TEXT_SUPPORTED macro.
+  Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03).
+  Optimize the zlib CMF byte in non-IDAT compressed chunks
+
+Version 1.5.3beta03 [April 16, 2011]
+  Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
+    snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
+    than __STDC__ (John Bowler).
+  Removed the PNG_PTR_NORETURN attribute because it too dangerous. It tells
+    the compiler that a user supplied callback (the error handler) does not
+    return, yet there is no guarantee in practice that the application code
+    will correctly implement the error handler because the compiler only
+    issues a warning if there is a mistake (John Bowler).
+  Removed the no-longer-used PNG_DEPSTRUCT macro.
+  Updated the zlib version to 1.2.5 in the VStudio project.
+  Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
+    pngwutil.c (John Bowler).
+  Fixed bug with stripping the filler or alpha channel when writing, that
+    was introduced in libpng-1.5.2beta01 (bug report by Andrew Church).
+
+Version 1.5.3beta04 [April 27, 2011]
+  Updated pngtest.png with the new zlib CMF optimization.
+  Cleaned up conditional compilation code and of background/gamma handling
+    Internal changes only except a new option to avoid compiling the
+    png_build_grayscale_palette API (which is not used at all internally.)
+    The main change is to move the transform tests (READ_TRANSFORMS,
+    WRITE_TRANSFORMS) up one level to the caller of the APIs.  This avoids
+    calls to spurious functions if all transforms are disabled and slightly
+    simplifies those functions.  Pngvalid modified to handle this.
+    A minor change is to stop the strip_16 and expand_16 interfaces from
+    disabling each other; this allows the future alpha premultiplication
+    code to use 16-bit intermediate values while still producing 8-bit output.
+    png_do_background and png_do_gamma have been simplified to take a single
+    pointer to the png_struct rather than pointers to every item required
+    from the png_struct. This makes no practical difference to the internal
+    code.
+  A serious bug in the pngvalid internal routine 'standard_display_init' has
+    been fixed - this failed to initialize the red channel and accidentally
+    initialized the alpha channel twice.
+  Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
+    avoid a possible clash with the png_jmpbuf macro on some platforms.
+
+Version 1.5.3beta05 [May 6, 2011]
+  Added the "_POSIX_SOURCE" feature test macro to ensure libpng sees the
+    correct API. _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and
+    pngvalid.c to ensure that POSIX conformant systems disable non-POSIX APIs.
+  Removed png_snprintf and added formatted warning messages.  This change adds
+    internal APIs to allow png_warning messages to have parameters without
+    requiring the host OS to implement snprintf.  As a side effect the
+    dependency of the tIME-supporting RFC1132 code on stdio is removed and
+    PNG_NO_WARNINGS does actually work now.
+  Pass "" instead of '\0' to png_default_error() in png_err().  This mistake
+    was introduced in libpng-1.2.20beta01.  This fixes CVE-2011-2691.
+  Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
+    optimization configurable.
+  IDAT compression failed if preceded by a compressed text chunk (bug
+    introduced in libpng-1.5.3beta01-02).  This was because the attempt to
+    reset the zlib stream in png_write_IDAT happened after the first IDAT
+    chunk had been deflated - much too late.  In this change internal
+    functions were added to claim/release the z_stream and, hopefully, make
+    the code more robust.  Also deflateEnd checking is added - previously
+    libpng would ignore an error at the end of the stream.
+
+Version 1.5.3beta06 [May 8, 2011]
+  Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
+  Implemented premultiplied alpha support: png_set_alpha_mode API
+
+Version 1.5.3beta07 [May 11, 2011]
+  Added expand_16 support to the high level interface.
+  Added named value and 'flag' gamma support to png_set_gamma.  Made a minor
+    change from the previous (unreleased) ABI/API to hide the exact value used
+    for Macs - it's not a good idea to embed this in the ABI!
+  Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
+    from pngpriv.h to png.h because they must be visible to applications
+    that call png_set_unknown_chunks().
+  Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
+    before IDAT.
+
+Version 1.5.3beta08 [May 16, 2011]
+  Improved "pngvalid --speed" to exclude more of pngvalid from the time.
+  Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
+  The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
+    parameters are supplied by the caller), while in the absence of cHRM
+    sRGB/Rec 709 values are still used.  This introduced a divide-by-zero
+    bug in png_handle_cHRM().
+  The bKGD chunk no longer overwrites the background value set by
+    png_set_background(), allowing the latter to be used before the file
+    header is read. It never performed any useful function to override
+    the default anyway.
+  Added memory overwrite and palette image checks to pngvalid.c
+    Previously palette image code was poorly checked. Since the transformation
+    code has a special palette path in most cases this was a severe weakness.
+  Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
+    expanding an indexed image, always expand to RGBA if transparency is
+    present.
+
+Version 1.5.3beta09 [May 17, 2011]
+  Reversed earlier 1.5.3 change of transformation order; move png_expand_16
+    back where it was.  The change doesn't work because it requires 16-bit
+    gamma tables when the code only generates 8-bit ones.  This fails
+    silently; the libpng code just doesn't do any gamma correction.  Moving
+    the tests back leaves the old, inaccurate, 8-bit gamma calculations, but
+    these are clearly better than none!
+
+Version 1.5.3beta10 [May 20, 2011]
+
+  png_set_background() and png_expand_16() did not work together correctly.
+    This problem is present in 1.5.2; if png_set_background is called with
+    need_expand false and the matching 16 bit color libpng erroneously just
+    treats it as an 8-bit color because of where png_do_expand_16 is in the
+    transform list.  This simple fix reduces the supplied colour to 8-bits,
+    so it gets smashed, but this is better than the current behavior.
+  Added tests for expand16, more fixes for palette image tests to pngvalid.
+    Corrects the code for palette image tests and disables attempts to
+    validate palette colors.
+
+Version 1.5.3rc01 [June 3, 2011]
+  No changes.
+
+Version 1.5.3rc02 [June 8, 2011]
+  Fixed uninitialized memory read in png_format_buffer() (Bug report by
+    Frank Busse, CVE-2011-2501, related to CVE-2004-0421).
+
+Version 1.5.3beta11 [June 11, 2011]
+  Fixed png_handle_sCAL which is broken in 1.5. This fixes CVE 2011-2692.
+  Added sCAL to pngtest.png
+  Revised documentation about png_set_user_limits() to say that it also affects
+    png writing.
+  Revised handling of png_set_user_limits() so that it can increase the
+    limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only
+    reduce it.
+  Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is
+    wrong (high by one) 25% of the time. Dividing by 257 with rounding is
+    wrong in 128 out of 65536 cases. Getting the right answer all the time
+    without division is easy.
+  Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro.
+  Added projects/owatcom, an IDE project for OpenWatcom to replace
+    scripts/makefile.watcom.  This project works with OpenWatcom 1.9. The
+    IDE autogenerates appropriate makefiles (libpng.mk) for batch processing.
+    The project is configurable, unlike the Visual Studio project, so long
+    as the developer has an awk.
+  Changed png_set_gAMA to limit the gamma value range so that the inverse
+    of the stored value cannot overflow the fixed point representation,
+    and changed other things OpenWatcom warns about.
+  Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows
+    pngvalid to build when ALPHA_MODE is not supported, which is required if
+    it is to build on libpng 1.4.
+  Removed string/memory macros that are no longer used and are not
+    necessarily fully supportable, particularly png_strncpy and png_snprintf.
+  Added log option to pngvalid.c and attempted to improve gamma messages.
+
+Version 1.5.3 [omitted]
+  People found the presence of a beta release following an rc release
+    to be confusing; therefore we bump the version to libpng-1.5.4beta01
+    and there will be no libpng-1.5.3 release.
+
+Version 1.5.4beta01 [June 14, 2011]
+  Made it possible to undefine PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+    to get the same (inaccurate) output as libpng-1.5.2 and earlier.
+  Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE
+    outside of an unknown-chunk block in png.h because they are also
+    needed for other uses.
+
+Version 1.5.4beta02 [June 14, 2011]
+  Fixed and clarified LEGACY 16-to-8 scaling code.
+  Added png_set_chop_16() API, to match inaccurate results from previous
+    libpng versions.
+  Removed the ACCURATE and LEGACY options (they are no longer useable)
+  Use the old scaling method for background if png_set_chop_16() was
+    called.
+  Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED
+
+Version 1.5.4beta03 [June 15, 2011]
+  Fixed a problem in png_do_expand_palette() exposed by optimization in
+    1.5.3beta06
+  Also removed a spurious and confusing "trans" member ("trans") from png_info.
+  The palette expand optimization prevented expansion to an intermediate RGBA
+    form if tRNS was present but alpha was marked to be stripped; this exposed
+    a check for tRNS in png_do_expand_palette() which is inconsistent with the
+    code elsewhere in libpng.
+  Correction to the expand_16 code; removed extra instance of
+    png_set_scale_16_to_8 from pngpriv.h
+
+Version 1.5.4beta04 [June 16, 2011]
+  Added a missing "#ifdef PNG_READ_BACKGROUND_SUPPORTED/#endif" in pngrtran.c
+  Added PNG_TRANSFORM_CHOP_16 to the high-level read transforms.
+  Made PNG_READ_16_TO_8_ACCURATE_SCALE configurable again.  If this is
+    not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built.
+  Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8
+
+Version 1.5.4beta05 [June 16, 2011]
+  Renamed png_set_strip_16() to png_set_scale_16() and renamed
+    png_set_chop_16() to png_set_strip(16) in an attempt to minimize the
+    behavior changes between libpng14 and libpng15.
+
+Version 1.5.4beta06 [June 18, 2011]
+  Fixed new bug that was causing both strip_16 and scale_16 to be applied.
+
+Version 1.5.4beta07 [June 19, 2011]
+  Fixed pngvalid, simplified macros, added checking for 0 in sCAL.
+    The ACCURATE scale macro is no longer defined in 1.5 - call the
+    png_scale_16_to_8 API.  Made sure that PNG_READ_16_TO_8 is still defined
+    if the png_strip_16_to_8 API is present.  png_check_fp_number now
+    maintains some state so that positive, negative and zero values are
+    identified.  sCAL uses these to be strictly spec conformant.
+
+Version 1.5.4beta08 [June 23, 2011]
+  Fixed pngvalid if ACCURATE_SCALE is defined.
+  Updated scripts/pnglibconf.h.prebuilt.
+
+Version 1.5.4rc01 [June 30, 2011]
+  Define PNG_ALLOCATED to "restrict" only if MSC_VER >= 1400.
+
+Version 1.5.4 [July 7, 2011]
+  No changes.
+
+Version 1.5.5beta01 [July 13, 2011]
+  Fixed some typos and made other minor changes in the manual.
+  Updated contrib/pngminus/makefile.std (Samuli Souminen)
+
+Version 1.5.5beta02 [July 14, 2011]
+  Revised Makefile.am and Makefile.in to look in the right directory for
+    pnglibconf.h.prebuilt
+
+Version 1.5.5beta03 [July 27, 2011]
+  Enabled compilation with g++ compiler.  This compiler does not recognize
+    the file extension, so it always compiles with C++ rules.  Made minor
+    changes to pngrutil.c to cast results where C++ expects it but C does not.
+  Minor editing of libpng.3 and libpng-manual.txt.
+
+Version 1.5.5beta04 [July 29, 2011]
+  Revised CMakeLists.txt (Clifford Yapp)
+  Updated commentary about the png_rgb_to_gray() default coefficients
+    in the manual and in pngrtran.c
+
+Version 1.5.5beta05 [August 17, 2011]
+  Prevent unexpected API exports from non-libpng DLLs on Windows.  The "_DLL"
+    is removed from the test of whether a DLL is being built (this erroneously
+    caused the libpng APIs to be marked as DLL exports in static builds under
+    Microsoft Visual Studio).  Almost all of the libpng building configuration
+    is moved from pngconf.h to pngpriv.h, but PNG_DLL_EXPORT remains in
+    pngconf.h, though, so that it is colocated with the import definition (it
+    is no longer used anywhere in the installed headers).  The VStudio project
+    definitions have been cleaned up: "_USRDLL" has been removed from the
+    static library builds (this was incorrect), and PNG_USE_DLL has been added
+    to pngvalid to test the functionality (pngtest does not supply it,
+    deliberately).  The spurious "_EXPORTS" has been removed from the
+    libpng build (all these errors were a result of copy/paste between project
+    configurations.)
+  Added new types and internal functions for CIE RGB end point handling to
+    pngpriv.h (functions yet to be implemented).
+
+Version 1.5.5beta06 [August 26, 2011]
+  Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set in CMakeLists.txt
+    (Clifford Yap)
+  Fixes to rgb_to_gray and cHRM XYZ APIs (John Bowler):
+    The rgb_to_gray code had errors when combined with gamma correction.
+    Some pixels were treated as true grey when they weren't and such pixels
+    and true grey ones were not gamma corrected (the original value of the
+    red component was used instead).  APIs to get and set cHRM using color
+    space end points have been added and the rgb_to_gray code that defaults
+    based on cHRM, and the divide-by-zero bug in png_handle_cHRM (CERT
+    VU#477046, CVE-2011-3328, introduced in 1.5.4) have been corrected.
+  A considerable number of tests has been added to pngvalid for the
+    rgb_to_gray transform.
+  Arithmetic errors in rgb_to_gray whereby the calculated gray value was
+    truncated to the bit depth rather than rounded have been fixed except in
+    the 8-bit non-gamma-corrected case (where consistency seems more important
+    than correctness.)  The code still has considerable inaccuracies in the
+    8-bit case because 8-bit linear arithmetic is used.
+
+Version 1.5.5beta07 [September 7, 2011]
+  Added "$(ARCH)" option to makefile.darwin
+  Added SunOS support to configure.ac and Makefile.am
+  Changed png_chunk_benign_error() to png_warning() in png.c, in
+    png_XYZ_from_xy_checked().
+
+Version 1.5.5beta08 [September 10, 2011]
+  Fixed 64-bit compilation errors (gcc). The errors fixed relate
+    to conditions where types that are 32 bits in the GCC 32-bit
+    world (uLong and png_size_t) become 64 bits in the 64-bit
+    world.  This produces potential truncation errors which the
+    compiler correctly flags.
+  Relocated new HAVE_SOLARIS_LD definition in configure.ac
+  Constant changes for 64-bit compatibility (removal of L suffixes). The
+    16-bit cases still use "L" as we don't have a 16-bit test system.
+
+Version 1.5.5rc01 [September 15, 2011]
+  Removed "L" suffixes in pngpriv.h
+
+Version 1.5.5 [September 22, 2011]
+  No changes.
+
+Version 1.5.6beta01 [September 22, 2011]
+  Fixed some 64-bit type conversion warnings in pngrtran.c
+  Moved row_info from png_struct to a local variable.
+  The various interlace mask arrays have been made into arrays of
+    bytes and made PNG_CONST and static (previously some arrays were
+    marked PNG_CONST and some weren't).
+  Additional checks have been added to the transform code to validate the
+    pixel depths after the transforms on both read and write.
+  Removed some redundant code from pngwrite.c, in png_destroy_write_struct().
+  Changed chunk reading/writing code to use png_uint_32 instead of png_byte[4].
+    This removes the need to allocate temporary strings for chunk names on
+    the stack in the read/write code.  Unknown chunk handling still uses the
+    string form because this is exposed in the API.
+
+Version 1.5.6beta02 [September 26, 2011]
+  Added a note in the manual the png_read_update_info() must be called only
+    once with a particular info_ptr.
+  Fixed a typo in the definition of the new PNG_STRING_FROM_CHUNK(s,c) macro.
+
+Version 1.5.6beta03 [September 28, 2011]
+  Revised test-pngtest.sh to report FAIL when pngtest fails.
+  Added "--strict" option to pngtest, to report FAIL when the failure is
+    only because the resulting valid files are different.
+  Revised CMakeLists.txt to work with mingw and removed some material from
+    CMakeLists.txt that is no longer useful in libpng-1.5.
+
+Version 1.5.6beta04 [October 5, 2011]
+  Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")."
+
+Version 1.5.6beta05 [October 12, 2011]
+  Speed up png_combine_row() for interlaced images. This reduces the generality
+    of the code, allowing it to be optimized for Adam7 interlace.  The masks
+    passed to png_combine_row() are now generated internally, avoiding
+    some code duplication and localizing the interlace handling somewhat.
+  Align png_struct::row_buf - previously it was always unaligned, caused by
+    a bug in the code that attempted to align it; the code needs to subtract
+    one from the pointer to take account of the filter byte prepended to
+    each row.
+  Optimized png_combine_row() when rows are aligned. This gains a small
+    percentage for 16-bit and 32-bit pixels in the typical case where the
+    output row buffers are appropriately aligned. The optimization was not
+    previously possible because the png_struct buffer was always misaligned.
+  Fixed bug in png_write_chunk_header() debug print, introduced in 1.5.6beta01.
+
+Version 1.5.6beta06 [October 17, 2011]
+  Removed two redundant tests for uninitialized row.
+  Fixed a relatively harmless memory overwrite in compressed text writing
+    with a 1 byte zlib buffer.
+  Add ability to call png_read_update_info multiple times to pngvalid.c.
+  Fixes for multiple calls to png_read_update_info. These fixes attend to
+    most of the errors revealed in pngvalid, however doing the gamma work
+    twice results in inaccuracies that can't be easily fixed.  There is now
+    a warning in the code if this is going to happen.
+  Turned on multiple png_read_update_info in pngvalid transform tests.
+  Prevent libpng from overwriting unused bits at the end of the image when
+    it is not byte aligned, while reading. Prior to libpng-1.5.6 libpng would
+    overwrite the partial byte at the end of each row if the row width was not
+    an exact multiple of 8 bits and the image is not interlaced.
+
+Version 1.5.6beta07 [October 21, 2011]
+  Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row
+    (Mans Rullgard).
+
+Version 1.5.6rc01 [October 26, 2011]
+  Changed misleading "Missing PLTE before cHRM" warning to "Out of place cHRM"
+
+Version 1.5.6rc02 [October 27, 2011]
+  Added LSR() macro to defend against buggy compilers that evaluate non-taken
+    code branches and complain about out-of-range shifts.
+
+Version 1.5.6rc03 [October 28, 2011]
+  Renamed the LSR() macro to PNG_LSR() and added PNG_LSL() macro.
+  Fixed compiler warnings with Intel and MSYS compilers. The logical shift
+    fix for Microsoft Visual C is required by other compilers, so this
+    enables that fix for all compilers when using compile-time constants.
+    Under MSYS 'byte' is a name declared in a system header file, so we
+    changed the name of a local variable to avoid the warnings that result.
+  Added #define PNG_ALIGN_TYPE PNG_ALIGN_NONE to contrib/pngminim/*/pngusr.h
+
+Version 1.5.6 [November 3, 2011]
+  No changes.
+
+Version 1.5.7beta01 [November 4, 2011]
+  Added support for ARM processor, when decoding all PNG up-filtered rows
+    and any other-filtered rows with 3 or 4 bytes per pixel (Mans Rullgard).
+  Fixed bug in pngvalid on early allocation failure; fixed type cast in
+    pngmem.c; pngvalid would attempt to call png_error() if the allocation
+    of a png_struct or png_info failed. This would probably have led to a
+    crash.  The pngmem.c implementation of png_malloc() included a cast
+    to png_size_t which would fail on large allocations on 16-bit systems.
+  Fix for the preprocessor of the Intel C compiler. The preprocessor
+    splits adjacent @ signs with a space; this changes the concatenation
+    token from @-@-@ to PNG_JOIN; that should work with all compiler
+    preprocessors.
+  Paeth filter speed improvements from work by Siarhei Siamashka. This
+    changes the 'Paeth' reconstruction function to improve the GCC code
+    generation on x86. The changes are only part of the suggested ones;
+    just the changes that definitely improve speed and remain simple.
+    The changes also slightly increase the clarity of the code.
+
+Version 1.5.7beta02 [November 11, 2011]
+  Check compression_type parameter in png_get_iCCP and remove spurious
+    casts. The compression_type parameter is always assigned to, so must
+    be non-NULL. The cast of the profile length potentially truncated the
+    value unnecessarily on a 16-bit int system, so the cast of the (byte)
+    compression type to (int) is specified by ANSI-C anyway.
+  Fixed FP division by zero in pngvalid.c; the 'test_pixel' code left
+    the sBIT fields in the test pixel as 0, which resulted in a floating
+    point division by zero which was irrelevant but causes systems where
+    FP exceptions cause a crash. Added code to pngvalid to turn on FP
+    exceptions if the appropriate glibc support is there to ensure this is
+    tested in the future.
+  Updated scripts/pnglibconf.mak and scripts/makefile.std to handle the
+    new PNG_JOIN macro.
+  Added versioning to pnglibconf.h comments.
+  Simplified read/write API initial version; basic read/write tested on
+    a variety of images, limited documentation (in the header file.)
+  Installed more accurate linear to sRGB conversion tables. The slightly
+    modified tables reduce the number of 16-bit values that
+    convert to an off-by-one 8-bit value.  The "makesRGB.c" code that was used
+    to generate the tables is now in a contrib/sRGBtables sub-directory.
+
+Version 1.5.7beta03 [November 17, 2011]
+  Removed PNG_CONST from the sRGB table declarations in pngpriv.h and png.c
+  Added run-time detection of NEON support.
+  Added contrib/libtests; includes simplified API test and timing test and
+    a color conversion utility for rapid checking of failed 'pngstest' results.
+  Multiple transform bug fixes plus a work-round for double gamma correction.
+    libpng does not support more than one transform that requires linear data
+    at once - if this is tried typically the results is double gamma
+    correction. Since the simplified APIs can need rgb to gray combined with
+    a compose operation it is necessary to do one of these outside the main
+    libpng transform code. This check-in also contains fixes to various bugs
+    in the simplified APIs themselves and to some bugs in compose and rgb to
+    gray (on palette) itself.
+  Fixes for C++ compilation using g++ When libpng source is compiled
+    using g++. The compiler imposes C++ rules on the C source; thus it
+    is desirable to make the source work with either C or C++ rules
+    without throwing away useful error information.  This change adds
+    png_voidcast to allow C semantic (void*) cases or the corresponding
+    C++ static_cast operation, as appropriate.
+  Added --noexecstack to assembler file compilation. GCC does not set
+    this on assembler compilation, even though it does on C compilation.
+    This creates security issues if assembler code is enabled; the
+    work-around is to set it by default in the flags for $(CCAS)
+  Work around compilers that don't support declaration of const data. Some
+    compilers fault 'extern const' data declarations (because the data is
+    not initialized); this turns on const-ness only for compilers where
+    this is known to work.
+
+Version 1.5.7beta04 [November 17, 2011]
+  Since the gcc driver does not recognize the --noexecstack flag, we must
+    use the -Wa prefix to have it passed through to the assembler.
+    Also removed a duplicate setting of this flag.
+  Added files that were omitted from the libpng-1.5.7beta03 zip distribution.
+
+Version 1.5.7beta05 [November 25, 2011]
+  Removed "zTXt" from warning in generic chunk decompression function.
+  Validate time settings passed to png_set_tIME() and png_convert_to_rfc1123()
+    (Frank Busse). Note: This prevented CVE-2015-7981 from affecting
+    libpng-1.5.7 and later.
+  Added MINGW support to CMakeLists.txt
+  Reject invalid compression flag or method when reading the iTXt chunk.
+  Backed out 'simplified' API changes. The API seems too complex and there
+    is a lack of consensus or enthusiasm for the proposals.  The API also
+    reveals significant bugs inside libpng (double gamma correction and the
+    known bug of being unable to retrieve a corrected palette). It seems
+    better to wait until the bugs, at least, are corrected.
+  Moved pngvalid.c into contrib/libtests
+  Rebuilt Makefile.in, configure, etc., with autoconf-2.68
+
+Version 1.5.7rc01 [December 1, 2011]
+  Replaced an "#if" with "#ifdef" in pngrtran.c
+  Revised #if PNG_DO_BC block in png.c (use #ifdef and add #else)
+
+Version 1.5.7rc02 [December 5, 2011]
+  Revised project files and contrib/pngvalid/pngvalid.c to account for
+    the relocation of pngvalid into contrib/libtests.
+  Revised pngconf.h to use " __declspec(restrict)" only when MSC_VER >= 1400,
+    as in libpng-1.5.4.
+  Put CRLF line endings in the owatcom project files.
+
+Version 1.5.7rc03 [December 7, 2011]
+  Updated CMakeLists.txt to account for the relocation of pngvalid.c
+
+Version 1.5.7 [December 15, 2011]
+  Minor fixes to pngvalid.c for gcc 4.6.2 compatibility to remove warnings
+    reported by earlier versions.
+  Fixed minor memset/sizeof errors in pngvalid.c.
+
+Version 1.6.0beta01 [December 15, 2011]
+  Removed machine-generated configure files from the GIT repository (they will
+    continue to appear in the tarball distributions and in the libpng15 and
+    earlier GIT branches).
+  Restored the new 'simplified' API, which was started in libpng-1.5.7beta02
+    but later deleted from libpng-1.5.7beta05.
+  Added example programs for the new 'simplified' API.
+  Added ANSI-C (C90) headers and require them, and take advantage of the
+    change. Also fixed some of the projects/* and contrib/* files that needed
+    updates for libpng16 and the move of pngvalid.c.
+    With this change the required ANSI-C header files are assumed to exist: the
+    implementation must provide float.h, limits.h, stdarg.h and stddef.h and
+    libpng relies on limits.h and stddef.h existing and behaving as defined
+    (the other two required headers aren't used).  Non-ANSI systems that don't
+    have stddef.h or limits.h will have to provide an appropriate fake
+    containing the relevant types and #defines.
+  Dropped support for 16-bit platforms. The use of FAR/far has been eliminated
+    and the definition of png_alloc_size_t is now controlled by a flag so
+    that 'small size_t' systems can select it if necessary.  Libpng 1.6 may
+    not currently work on such systems -- it seems likely that it will
+    ask 'malloc' for more than 65535 bytes with any image that has a
+    sufficiently large row size (rather than simply failing to read such
+    images).
+  New tools directory containing tools used to generate libpng code.
+  Fixed race conditions in parallel make builds. With higher degrees of
+    parallelism during 'make' the use of the same temporary file names such
+    as 'dfn*' can result in a race where a temporary file from one arm of the
+    build is deleted or overwritten in another arm.  This changes the
+    temporary files for suffix rules to always use $* and ensures that the
+    non-suffix rules use unique file names.
+
+Version 1.6.0beta02 [December 21, 2011]
+  Correct configure builds where build and source directories are separate.
+    The include path of 'config.h' was erroneously made relative in pngvalid.c
+    in libpng 1.5.7.
+
+Version 1.6.0beta03 [December 22, 2011]
+  Start-up code size improvements, error handler flexibility. These changes
+    alter how the tricky allocation of the initial png_struct and png_info
+    structures are handled. png_info is now handled in pretty much the same
+    way as everything else, except that the allocations handle NULL return
+    silently.  png_struct is changed in a similar way on allocation and on
+    deallocation a 'safety' error handler is put in place (which should never
+    be required).  The error handler itself is changed to permit mismatches
+    in the application and libpng error buffer size; however, this means a
+    silent change to the API to return the jmp_buf if the size doesn't match
+    the size from the libpng compilation; libpng now allocates the memory and
+    this may fail.  Overall these changes result in slight code size
+    reductions; however, this is a reduction in code that is always executed
+    so is particularly valuable.  Overall on a 64-bit system the libpng DLL
+    decreases in code size by 1733 bytes.  pngerror.o increases in size by
+    about 465 bytes because of the new functionality.
+  Added png_convert_to_rfc1123_buffer() and deprecated png_convert_to_rfc1123()
+    to avoid including a spurious buffer in the png_struct.
+
+Version 1.6.0beta04 [December 30, 2011]
+  Regenerated configure scripts with automake-1.11.2
+  Eliminated png_info_destroy(). It is now used only in png.c and only calls
+    one other internal function and memset().
+  Enabled png_get_sCAL_fixed() if floating point APIs are enabled. Previously
+    it was disabled whenever internal fixed point arithmetic was selected,
+    which meant it didn't exist even on systems where FP was available but not
+    preferred.
+  Added pngvalid.c compile time checks for const APIs.
+  Implemented 'restrict' for png_info and png_struct. Because of the way
+    libpng works both png_info and png_struct are always accessed via a
+    single pointer.  This means adding C99 'restrict' to the pointer gives
+    the compiler some opportunity to optimize the code.  This change allows
+    that.
+  Moved AC_MSG_CHECKING([if libraries can be versioned]) later to the proper
+    location in configure.ac (Gilles Espinasse).
+  Changed png_memcpy to C assignment where appropriate. Changed all those
+    uses of png_memcpy that were doing a simple assignment to assignments
+    (all those cases where the thing being copied is a non-array C L-value).
+  Added some error checking to png_set_*() routines.
+  Removed the reference to the non-exported function png_memcpy() from
+    example.c.
+  Fixed the Visual C 64-bit build - it requires jmp_buf to be aligned, but
+    it had become misaligned.
+  Revised contrib/pngminus/pnm2png.c to avoid warnings when png_uint_32
+    and unsigned long are of different sizes.
+
+Version 1.6.0beta05 [January 15, 2012]
+  Updated manual with description of the simplified API (copied from png.h)
+  Fix bug in pngerror.c: some long warnings were being improperly truncated
+    (CVE-2011-3464, bug introduced in libpng-1.5.3beta05).
+
+Version 1.6.0beta06 [January 24, 2012]
+  Added palette support to the simplified APIs. This commit
+    changes some of the macro definitions in png.h, app code
+    may need corresponding changes.
+  Increased the formatted warning buffer to 192 bytes.
+  Added color-map support to simplified API. This is an initial version for
+    review; the documentation has not yet been updated.
+  Fixed Min/GW uninstall to remove libpng.dll.a
+
+Version 1.6.0beta07 [January 28, 2012]
+  Eliminated Intel icc/icl compiler warnings. The Intel (GCC derived)
+    compiler issues slightly different warnings from those issued by the
+    current vesions of GCC. This eliminates those warnings by
+    adding/removing casts and small code rewrites.
+  Updated configure.ac from autoupdate: added --enable-werror option.
+    Also some layout regularization and removal of introduced tab characters
+    (replaced with 3-character indentation).  Obsolete macros identified by
+    autoupdate have been removed; the replacements are all in 2.59 so
+    the pre-req hasn't been changed.  --enable-werror checks for support
+    for -Werror (or the given argument) in the compiler.  This mimics the
+    gcc configure option by allowing -Werror to be turned on safely; without
+    the option the tests written in configure itself fail compilation because
+    they cause compiler warnings.
+  Rewrote autogen.sh to run autoreconf instead of running tools one-by-one.
+  Conditionalize the install rules for MINGW and CYGWIN in CMakeLists.txt and
+    set CMAKE_LIBRARY_OUTPUT_DIRECTORY to "lib" on all platforms (C. Yapp).
+  Freeze libtool files in the 'scripts' directory. This version of autogen.sh
+    attempts to dissuade people from running it when it is not, or should not,
+    be necessary.  In fact, autogen.sh does not work when run in a libpng
+    directory extracted from a tar distribution anymore. You must run it in
+    a GIT clone instead.
+  Added two images to contrib/pngsuite (1-bit and 2-bit transparent grayscale),
+    and renamed three whose names were inconsistent with those in
+    pngsuite/README.txt.
+
+Version 1.6.0beta08 [February 1, 2012]
+  Fixed Image::colormap misalignment in pngstest.c
+  Check libtool/libtoolize version number (2.4.2) in configure.ac
+  Divide test-pngstest.sh into separate pngstest runs for basic and
+    transparent images.
+  Moved automake options to AM_INIT_AUTOMAKE in configure.ac
+  Added color-tests, silent-rules (Not yet implemented in Makefile.am) and
+    version checking to configure.ac
+  Improved pngstest speed by not doing redundant tests and add const to
+    the background parameter of png_image_finish_read. The --background
+    option is now done automagically only when required, so that commandline
+    option no longer exists.
+  Cleaned up pngpriv.h to consistently declare all functions and data.
+    Also eliminated PNG_CONST_DATA, which is apparently not needed but we
+    can't be sure until it is gone.
+  Added symbol prefixing that allows all the libpng external symbols
+    to be prefixed (suggested by Reuben Hawkins).
+  Updated "ftbb*.png" list in the owatcom and vstudio projects.
+  Fixed 'prefix' builds on clean systems. The generation of pngprefix.h
+    should not require itself.
+  Updated INSTALL to explain that autogen.sh must be run in a GIT clone,
+    not in a libpng directory extracted from a tar distribution.
+
+Version 1.6.0beta09 [February 1, 2012]
+  Reverted the prebuilt configure files to libpng-1.6.0beta05 condition.
+
+Version 1.6.0beta10 [February 3, 2012]
+  Added Z_SOLO for zlib-1.2.6+ and correct pngstest tests
+  Updated list of test images in CMakeLists.txt
+  Updated the prebuilt configure files to current condition.
+  Revised INSTALL information about autogen.sh; it works in tar distributions.
+
+Version 1.6.0beta11 [February 16, 2012]
+  Fix character count in pngstest command in projects/owatcom/pngstest.tgt
+  Revised test-pngstest.sh to report PASS/FAIL for each image.
+  Updated documentation about the simplified API.
+  Corrected estimate of error in libpng png_set_rgb_to_gray API.  The API is
+    extremely inaccurate for sRGB conversions because it uses an 8-bit
+    intermediate linear value and it does not use the sRGB transform, so it
+    suffers from the known instability in gamma transforms for values close
+    to 0 (see Poynton).  The net result is that the calculation has a maximum
+    error of 14.99/255; 0.5/255^(1/2.2).  pngstest now uses 15 for the
+    permitted 8-bit error. This may still not be enough because of arithmetic
+    error.
+  Removed some unused arrays (with #ifdef) from png_read_push_finish_row().
+  Fixed a memory overwrite bug in simplified read of RGB PNG with
+    non-linear gamma Also bugs in the error checking in pngread.c and changed
+    quite a lot of the checks in pngstest.c to be correct; either correctly
+    written or not over-optimistic.  The pngstest changes are insufficient to
+    allow all possible RGB transforms to be passed; pngstest cmppixel needs
+    to be rewritten to make it clearer which errors it allows and then changed
+    to permit known inaccuracies.
+  Removed tests for no-longer-used *_EMPTY_PLTE_SUPPORTED from pngstruct.h
+  Fixed fixed/float API export conditionals. 1) If FIXED_POINT or
+    FLOATING_POINT options were switched off, png.h ended up with lone ';'
+    characters.  This is not valid ANSI-C outside a function.  The ';'
+    characters have been moved inside the definition of PNG_FP_EXPORT and
+    PNG_FIXED_EXPORT. 2) If either option was switched off, the declaration
+    of the corresponding functions were completely omitted, even though some
+    of them are still used internally.  The result is still valid, but
+    produces warnings from gcc with some warning options (including -Wall). The
+    fix is to cause png.h to declare the functions with PNG_INTERNAL_FUNCTION
+    when png.h is included from pngpriv.h.
+  Check for invalid palette index while reading paletted PNG.  When one is
+    found, issue a warning and increase png_ptr->num_palette accordingly.
+    Apps are responsible for checking to see if that happened.
+
+Version 1.6.0beta12 [February 18, 2012]
+  Do not increase num_palette on invalid_index.
+  Relocated check for invalid palette index to pngrtran.c, after unpacking
+    the sub-8-bit pixels.
+  Fixed CVE-2011-3026 buffer overrun bug.  This bug was introduced when
+    iCCP chunk support was added at libpng-1.0.6. Deal more correctly with the
+    test on iCCP chunk length. Also removed spurious casts that may hide
+    problems on 16-bit systems.
+
+Version 1.6.0beta13 [February 24, 2012]
+  Eliminated redundant png_push_read_tEXt|zTXt|iTXt|unknown code from
+    pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
+    now that png_ptr->buffer is inaccessible to applications, the special
+    handling is no longer useful.
+  Added PNG_SAFE_LIMITS feature to pnglibconf.dfa, pngpriv.h, and new
+    pngusr.dfa to reset the user limits to safe ones if PNG_SAFE_LIMITS is
+    defined.  To enable, use "CPPFLAGS=-DPNG_SAFE_LIMITS_SUPPORTED=1" on the
+    configure command or put #define PNG_SAFE_LIMITS_SUPPORTED in
+    pnglibconf.h.prebuilt and pnglibconf.h.
+
+Version 1.6.0beta14 [February 27, 2012]
+  Added information about the new limits in the manual.
+  Updated Makefile.in
+
+Version 1.6.0beta15 [March 2, 2012]
+  Removed unused "current_text" members of png_struct and the png_free()
+    of png_ptr->current_text from pngread.c
+  Rewrote pngstest.c for substantial speed improvement.
+  Fixed transparent pixel and 16-bit rgb tests in pngstest and removed a
+    spurious check in pngwrite.c
+  Added PNG_IMAGE_FLAG_FAST for the benefit of applications that store
+    intermediate files, or intermediate in-memory data, while processing
+    image data with the simplified API.  The option makes the files larger
+    but faster to write and read.  pngstest now uses this by default; this
+    can be disabled with the --slow option.
+  Improved pngstest fine tuning of error numbers, new test file generator.
+    The generator generates images that test the full range of sample values,
+    allow the error numbers in pngstest to be tuned and checked.  makepng
+    also allows generation of images with extra chunks, although this is
+    still work-in-progress.
+  Added check for invalid palette index while reading.
+  Fixed some bugs in ICC profile writing. The code should now accept
+    all potentially valid ICC profiles and reject obviously invalid ones.
+    It now uses png_error() to do so rather than casually writing a PNG
+    without the necessary color data.
+  Removed whitespace from the end of lines in all source files and scripts.
+
+Version 1.6.0beta16 [March 6, 2012]
+  Relocated palette-index checking function from pngrutil.c to pngtrans.c
+  Added palette-index checking while writing.
+  Changed png_inflate() and calling routines to avoid overflow problems.
+    This is an intermediate check-in that solves the immediate problems and
+    introduces one performance improvement (avoiding a copy via png_ptr->zbuf.)
+    Further changes will be made to make ICC profile handling more secure.
+  Fixed build warnings (MSVC, GCC, GCC v3). Cygwin GCC with default options
+    declares 'index' as a global, causing a warning if it is used as a local
+    variable.  GCC 64-bit warns about assigning a (size_t) (unsigned 64-bit)
+    to an (int) (signed 32-bit).  MSVC, however, warns about using the
+    unary '-' operator on an unsigned value (even though it is well defined
+    by ANSI-C to be ~x+1).  The padding calculation was changed to use a
+    different method.  Removed the tests on png_ptr->pass.
+  Added contrib/libtests/tarith.c to test internal arithmetic functions from
+    png.c. This is a libpng maintainer program used to validate changes to the
+    internal arithmetic functions.
+  Made read 'inflate' handling like write 'deflate' handling. The read
+    code now claims and releases png_ptr->zstream, like the write code.
+    The bug whereby the progressive reader failed to release the zstream
+    is now fixed, all initialization is delayed, and the code checks for
+    changed parameters on deflate rather than always calling
+    deflatedEnd/deflateInit.
+  Validate the zTXt strings in pngvalid.
+  Added code to validate the windowBits value passed to deflateInit2().
+    If the call to deflateInit2() is wrong a png_warning will be issued
+    (in fact this is harmless, but the PNG data produced may be sub-optimal).
+
+Version 1.6.0beta17 [March 10, 2012]
+  Fixed PNG_LIBPNG_BUILD_BASE_TYPE definition. 
+  Reject all iCCP chunks after the first, even if the first one is invalid.
+  Deflate/inflate was reworked to move common zlib calls into single
+    functions [rw]util.c.  A new shared keyword check routine was also added
+    and the 'zbuf' is no longer allocated on progressive read.  It is now
+    possible to call png_inflate() incrementally.  A warning is no longer
+    issued if the language tag or translated keyword in the iTXt chunk
+    has zero length.
+  If benign errors are disabled use maximum window on ancillary inflate.
+    This works round a bug introduced in 1.5.4 where compressed ancillary
+    chunks could end up with a too-small windowBits value in the deflate
+    header.
+
+Version 1.6.0beta18 [March 16, 2012]
+  Issue a png_benign_error() instead of png_warning() about bad palette index.
+  In pngtest, treat benign errors as errors if "-strict" is present.
+  Fixed an off-by-one error in the palette index checking function.
+  Fixed a compiler warning under Cygwin (Windows-7, 32-bit system)
+  Revised example.c to put text strings in a temporary character array
+    instead of directly assigning string constants to png_textp members.
+    This avoids compiler warnings when -Wwrite-strings is enabled.
+  Added output flushing to aid debugging under Visual Studio. Unfortunately
+    this is necessary because the VS2010 output window otherwise simply loses
+    the error messages on error (they weren't flushed to the window before
+    the process exited, apparently!)
+  Added configuration support for benign errors and changed the read
+    default. Also changed some warnings in the iCCP and sRGB handling
+    from to benign errors. Configuration now makes read benign
+    errors warnings and write benign errors to errors by default (thus
+    changing the behavior on read).  The simplified API always forces
+    read benign errors to warnings (regardless of the system default, unless
+    this is disabled in which case the simplified API can't be built.)
+
+Version 1.6.0beta19 [March 18, 2012]
+  Work around for duplicate row start calls; added warning messages.
+    This turns on PNG_FLAG_DETECT_UNINITIALIZED to detect app code that
+    fails to call one of the 'start' routines (not enabled in libpng-1.5
+    because it is technically an API change, since it did normally work
+    before.)  It also makes duplicate calls to png_read_start_row (an
+    internal function called at the start of the image read) benign, as
+    they were before changes to use png_inflate_claim. Somehow webkit is
+    causing this to happen; this is probably a mis-feature in the zlib
+    changes so this commit is only a work-round.
+  Removed erroneous setting of DETECT_UNINITIALIZED and added more
+    checks. The code now does a png_error if an attempt is made to do the
+    row initialization twice; this is an application error and it has
+    serious consequences because the transform data in png_struct is
+    changed by each call.
+  Added application error reporting and added chunk names to read
+    benign errors; also added --strict to pngstest - not enabled
+    yet because a warning is produced.
+  Avoid the double gamma correction warning in the simplified API.
+    This allows the --strict option to pass in the pngstest checks
+
+Version 1.6.0beta20 [March 29, 2012]
+  Changed chunk handler warnings into benign errors, incrementally load iCCP
+  Added checksum-icc.c to contrib/tools
+  Prevent PNG_EXPAND+PNG_SHIFT doing the shift twice.
+  Recognize known sRGB ICC profiles while reading; prefer writing the
+    iCCP profile over writing the sRGB chunk, controlled by the
+    PNG_sRGB_PROFILE_CHECKS option.
+  Revised png_set_text_2() to avoid potential memory corruption (fixes
+    CVE-2011-3048, also known as CVE-2012-3425).
+
+Version 1.6.0beta21 [April 27, 2012]
+  Revised scripts/makefile.darwin: use system zlib; remove quotes around
+    architecture list; add missing ppc architecture; add architecture options
+    to shared library link; don't try to create a shared lib based on missing
+    RELEASE variable.
+  Enable png_set_check_for_invalid_index() for both read and write.
+  Removed #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED in pngpriv.h around
+    declaration of png_handle_unknown().
+  Added -lssp_nonshared in a comment in scripts/makefile.freebsd
+    and changed deprecated NOOBJ and NOPROFILE to NO_OBJ and NO_PROFILE.
+
+Version 1.6.0beta22 [May 23, 2012]
+  Removed need for -Wno-cast-align with clang.  clang correctly warns on
+    alignment increasing pointer casts when -Wcast-align is passed. This
+    fixes the cases that clang warns about either by eliminating the
+    casts from png_bytep to png_uint_16p (pngread.c), or, for pngrutil.c
+    where the cast is previously verified or pngstest.c where it is OK, by
+    introducing new png_aligncast macros to do the cast in a way that clang
+    accepts.
+
+Version 1.6.0beta23 [June 6, 2012]
+  Revised CMakeLists.txt to not attempt to make a symlink under mingw.
+  Made fixes for new optimization warnings from gcc 4.7.0. The compiler
+    performs an optimization which is safe; however it then warns about it.
+    Changing the type of 'palette_number' in pngvalid.c removes the warning.
+  Do not depend upon a GCC feature macro being available for use in generating
+    the linker mapfile symbol prefix.
+  Improved performance of new do_check_palette_indexes() function (only
+    update the value when it actually increases, move test for whether
+    the check is wanted out of the function.
+
+Version 1.6.0beta24 [June 7, 2012]
+  Don't check palette indexes if num_palette is 0 (as it can be in MNG files).
+
+Version 1.6.0beta25 [June 16, 2012]
+  Revised png_set_keep_unknown_chunks() so num_chunks < 0 means ignore all
+    unknown chunks and all known chunks except for IHDR, PLTE, tRNS, IDAT,
+    and IEND.  Previously it only meant ignore all unknown chunks, the
+    same as num_chunks == 0. Revised png_image_skip_unused_chunks() to
+    provide a list of chunks to be processed instead of a list of chunks to
+    ignore.  Revised contrib/gregbook/readpng2.c accordingly.
+
+Version 1.6.0beta26 [July 10, 2012]
+  Removed scripts/makefile.cegcc from the *.zip and *.7z distributions; it
+    depends on configure, which is not included in those archives.
+  Moved scripts/chkfmt to contrib/tools.
+  Changed "a+w" to "u+w" in Makefile.in to fix CVE-2012-3386.
+
+Version 1.6.0beta27 [August 11, 2012]
+  Do not compile PNG_DEPRECATED, PNG_ALLOC and PNG_PRIVATE when __GNUC__ < 3.
+  Do not use __restrict when GNUC is <= 3.1
+  Removed references to png_zalloc() and png_zfree() from the manual.
+  Fixed configurations where floating point is completely disabled.  Because
+    of the changes to support symbol prefixing PNG_INTERNAL_FUNCTION declares
+    floating point APIs during libpng builds even if they are completely
+    disabled. This requires the png floating point types (png_double*) to be
+    declared even though the functions are never actually defined.  This
+    change provides a dummy definition so that the declarations work, yet any
+    implementation will fail to compile because of an incomplete type.
+  Re-eliminated the use of strcpy() in pngtest.c.  An unnecessary use of
+    strcpy() was accidentally re-introduced in libpng16; this change replaces
+    it with strncpy().
+  Eliminated use of png_sizeof(); use sizeof() instead.
+  Use a consistent style for (sizeof type) and (sizeof (array))
+  Cleanup of png_set_filler().  This function does very different things on
+    read and write.  In libpng 1.6 the two cases can be distinguished and
+    considerable code cleanup, and extra error checking, is possible.  This
+    makes calls on the write side that have no effect be ignored with a
+    png_app_error(), which can be disabled in the app using
+    png_set_benign_errors(), and removes the spurious use of usr_channels
+    on the read side.
+  Insist on autotools 1.12.1 for git builds because there are security issues
+    with 1.12 and insisting on anything less would allow 1.12 to be used.
+  Removed info_ptr->signature[8] from WRITE-only builds.
+  Add some conditions for compiling png_fixed().  This is a small function
+    but it requires "-lm" on some platforms.
+  Cause pngtest --strict to fail on any warning from libpng (not just errors)
+    and cause it not to fail at the comparison step if libpng lacks support
+    for writing chunks that it reads from the input (currently only implemented
+    for compressed text chunks).
+  Make all three "make check" test programs work without READ or WRITE support.
+    Now "make check" will succeed even if libpng is compiled with -DPNG_NO_READ
+    or -DPNG_NO_WRITE.  The tests performed are reduced, but the basic reading
+    and writing of a PNG file is always tested by one or more of the tests.
+  Consistently use strlen(), memset(), memcpy(), and memcmp() instead of the
+    png_strlen(), png_memset(), png_memcpy(), and png_memcmp() macros.
+  Removed the png_sizeof(), png_strlen(), png_memset(), png_memcpy(), and
+    png_memcmp() macros.
+  Work around gcc 3.x and Microsoft Visual Studio 2010 complaints. Both object
+    to the split initialization of num_chunks.
+
+Version 1.6.0beta28 [August 29, 2012]
+  Unknown handling fixes and clean up. This adds more correct option
+    control of the unknown handling, corrects the pre-existing bug where
+    the per-chunk 'keep' setting is ignored and makes it possible to skip
+    IDAT chunks in the sequential reader (broken in earlier 1.6 versions).
+    There is a new test program, test-unknown.c, which is a work in progress
+    (not currently part of the test suite).  Comments in the header files now
+    explain how the unknown handling works.
+  Allow fine grain control of unknown chunk APIs. This change allows
+    png_set_keep_unknown_chunks() to be turned off if not required and causes
+    both read and write to behave appropriately (on read this is only possible
+    if the user callback is used to handle unknown chunks).  The change
+    also removes the support for storing unknown chunks in the info_struct
+    if the only unknown handling enabled is via the callback, allowing libpng
+    to be configured with callback reading and none of the unnecessary code.
+  Corrected fix for unknown handling in pngtest. This reinstates the
+    libpng handling of unknown chunks other than vpAg and sTER (including
+    unsafe-to-copy chunks which were dropped before) and eliminates the
+    repositioning of vpAg and sTER in pngtest.png by changing pngtest.png
+    (so the chunks are where libpng would put them).
+  Added "tunknown" test and corrected a logic error in png_handle_unknown()
+    when SAVE support is absent.  Moved the shell test scripts for
+    contrib/libtests from the libpng top directory to contrib/libtests.
+    png_handle_unknown() must always read or skip the chunk, if
+    SAVE_UNKNOWN_CHUNKS is turned off *and* the application does not set
+    a user callback an unknown chunk will not be read, leading to a read
+    error, which was revealed by the "tunknown" test.
+  Cleaned up and corrected ICC profile handling.
+    contrib/libtests/makepng: corrected 'rgb' and 'gray' cases.  profile_error
+    messages could be truncated; made a correct buffer size calculation and
+    adjusted pngerror.c appropriately. png_icc_check_* checking improved;
+    changed the functions to receive the correct color type of the PNG on read
+    or write and check that it matches the color space of the profile (despite
+    what the comments said before, there is danger in assuming the app will
+    cope correctly with an RGB profile on a grayscale image and, since it
+    violates the PNG spec, allowing it is certain to produce inconsistent
+    app behavior and might even cause app crashes.) Check that profiles
+    contain the tags needed to process the PNG (tags all required by the ICC
+    spec). Removed unused PNG_STATIC from pngpriv.h.
+
+Version 1.6.0beta29 [September 4, 2012]
+  Fixed the simplified API example programs to add the *colormap parameter
+    to several of he API and improved the error message if the version field
+    is not set.
+  Added contrib/examples/* to the *.zip and *.7z distributions.
+  Updated simplified API synopses and description of the png_image structure
+    in the manual.
+  Made makepng and pngtest produce identical PNGs, add "--relaxed" option
+    to pngtest. The "--relaxed" option turns off the benign errors that are
+    enabled by default in pre-RC builds. makepng can now write ICC profiles
+    where the length has not been extended to a multiple of 4, and pngtest
+    now intercepts all libpng errors, allowing the previously-introduced
+    "--strict test" on no warnings to actually work.
+  Improved ICC profile handling including cHRM chunk generation and fixed
+    Cygwin+MSVC build errors. The ICC profile handling now includes more
+    checking.  Several errors that caused rejection of the profile are now
+    handled with a warning in such a way that the invalid profiles will be
+    read by default in release (but not pre-RC) builds but will not be
+    written by default.  The easy part of handling the cHRM chunk is written,
+    where the ICC profile contains the required data.  The more difficult
+    part plus guessing a gAMA value requires code to pass selected RGB values
+    through the profile.
+
+Version 1.6.0beta30 [October 24, 2012]
+  Changed ICC profile matrix/vector types to not depend on array type rules.
+    By the ANSI-C standard the new types should be identical to the previous
+    versions, and all known versions of gcc tested with the previous versions
+    except for GCC-4.2.1 work with this version.  The change makes the ANSI-C
+    rule that const applied to an array of elements applies instead to the
+    elements in the array moot by explicitly applying const to the base
+    elements of the png_icc_matrix and png_icc_vector types. The accidental
+    (harmless) 'const' previously applied to the parameters of two of the
+    functions have also been removed.
+  Added a work around for GCC 4.2 optimization bug.
+  Marked the broken (bad white point) original HP sRGB profiles correctly and
+    correct comments.
+  Added -DZ_SOLO to contrib/pngminim/*/makefile to work with zlib-1.2.7
+  Use /MDd for vstudio debug builds. Also added pngunkown to the vstudio
+    builds, fixed build errors and corrected a minor exit code error in
+    pngvalid if the 'touch' file name is invalid.
+  Add updated WARNING file to projects/vstudio from libpng 1.5/vstudio
+  Fixed build when using #define PNG_NO_READ_GAMMA in png_do_compose() in
+    pngrtran.c (Domani Hannes).
+
+Version 1.6.0beta31 [November 1, 2012]
+  Undid the erroneous change to vstudio/pngvalid build in libpng-1.6.0beta30.
+  Made pngvalid so that it will build outside the libpng source tree.
+  Made builds -DPNG_NO_READ_GAMMA compile (the unit tests still fail).
+  Made PNG_NO_READ_GAMMA switch off interfaces that depend on READ_GAMMA.
+    Prior to 1.6.0 switching off READ_GAMMA did unpredictable things to the
+    interfaces that use it (specifically, png_do_background in 1.4 would
+    simply display composite for grayscale images but do composition
+    with the incorrect arithmetic for color ones). In 1.6 the semantic
+    of -DPNG_NO_READ_GAMMA is changed to simply disable any interface that
+    depends on it; this obliges people who set it to consider whether they
+    really want it off if they happen to use any of the interfaces in
+    question (typically most users who disable it won't).
+  Fixed GUIDs in projects/vstudio. Some were duplicated or missing,
+    resulting in VS2010 having to update the files.
+  Removed non-working ICC profile support code that was mostly added to
+    libpng-1.6.0beta29 and beta30. There was too much code for too little
+    gain; implementing full ICC color correction may be desirable but is left
+    up to applications.
+
+Version 1.6.0beta32 [November 25, 2012]
+  Fixed an intermittent SEGV in pngstest due to an uninitialized array element.
+  Added the ability for contrib/libtests/makepng.c to make a PNG with just one
+    color. This is useful for debugging pngstest color inaccuracy reports.
+  Fixed error checking in the simplified write API (Olaf van der Spek)
+  Made png_user_version_check() ok to use with libpng version 1.10.x and later.
+
+Version 1.6.0beta33 [December 15, 2012]
+  Fixed typo in png.c (PNG_SET_CHUNK_MALLOC_MAX should be PNG_CHUNK_MALLOC_MAX)
+    that causes the MALLOC_MAX limit not to work (John Bowler)
+  Change png_warning() to png_app_error() in pngwrite.c and comment the
+    fall-through condition.
+  Change png_warning() to png_app_warning() in png_write_tRNS().
+  Rearranged the ARM-NEON optimizations: Isolated the machine specific code
+    to the hardware subdirectory and added comments to pngrutil.c so that
+    implementors of other optimizations know what to do.
+  Fixed cases of unquoted DESTDIR in Makefile.am
+  Rebuilt Makefile.in, etc., with autoconf-2.69 and automake-1.12.5.
+
+Version 1.6.0beta34 [December 19, 2012]
+  Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
+  Disassembled the version number in scripts/options.awk (necessary for
+    building on SunOs).
+
+Version 1.6.0beta35 [December 23, 2012]
+  Made default Zlib compression settings be configurable. This adds #defines to
+    pnglibconf.h to control the defaults.
+  Fixed Windows build issues, enabled ARM compilation. Various warnings issued
+    by earlier versions of GCC fixed for Cygwin and Min/GW (which both use old
+    GCCs.) ARM support is enabled by default in zlib.props (unsupported by
+    Microsoft) and ARM compilation is made possible by deleting the check for
+    x86. The test programs cannot be run because they are not signed.
+
+Version 1.6.0beta36 [January 2, 2013]
+  Discontinued distributing libpng-1.x.x.tar.bz2.
+  Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar.
+  Rebuilt configure with autoconf-2.69 (inadvertently not done in beta33)
+  Fixed 'make distcheck' on SUN OS - libpng.so was not being removed
+
+Version 1.6.0beta37 [January 10, 2013]
+  Fixed conceivable but difficult to repro overflow. Also added two test
+    programs to generate and test a PNG which should have the problem.
+
+Version 1.6.0beta39 [January 19, 2013]
+  Again corrected attempt at overflow detection in png_set_unknown_chunks()
+  (CVE-2013-7353).  Added overflow detection in png_set_sPLT() and
+  png_set_text_2() (CVE-2013-7354).
+
+Version 1.6.0beta40 [January 20, 2013]
+  Use consistent handling of overflows in text, sPLT and unknown png_set_* APIs
+
+Version 1.6.0rc01 [January 26, 2013]
+  No changes.
+
+Version 1.6.0rc02 [February 4, 2013]
+  Added png_get_palette_max() function.
+
+Version 1.6.0rc03 [February 5, 2013]
+  Fixed the png_get_palette_max API.
+
+Version 1.6.0rc04 [February 7, 2013]
+  Turn serial tests back on (recently turned off by autotools upgrade).
+
+Version 1.6.0rc05 [February 8, 2013]
+  Update manual about png_get_palette_max().
+
+Version 1.6.0rc06 [February 9, 2013]
+  Fixed missing dependency in --prefix builds The intermediate
+    internal 'prefix.h' file can only be generated correctly after
+    pnglibconf.h, however the dependency was not in Makefile.am.  The
+    symptoms are unpredictable depending on the order make chooses to
+    build pngprefix.h and pnglibconf.h, often the error goes unnoticed
+    because there is a system pnglibconf.h to use instead.
+
+Version 1.6.0rc07 [February 10, 2013]
+  Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+    block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly.
+
+Version 1.6.0rc08 [February 10, 2013]
+  Fix typo in png.h #ifdef
+
+Version 1.6.0 [February 14, 2013]
+  No changes.
+
+Version 1.6.1beta01 [February 16, 2013]
+  Made symbol prefixing work with the ARM neon optimizations. Also allow
+    pngpriv.h to be included for preprocessor definitions only, so it can
+    be used in non-C/C++ files. Back ported from libpng 1.7.
+  Made sRGB check numbers consistent.
+  Ported libpng 1.5 options.awk/dfn file handling to 1.6, fixed one bug.
+  Removed cc -E workround, corrected png_get_palette_max API Tested on
+    SUN OS cc 5.9, which demonstrates the tokenization problem previously
+    avoided by using /lib/cpp.  Since all .dfn output is now protected in
+    double quotes unless it is to be macro substituted the fix should
+    work everywhere.
+  Enabled parallel tests - back ported from libpng-1.7.
+  scripts/pnglibconf.dfa formatting improvements back ported from libpng17.
+  Fixed a race condition in the creation of the build 'scripts' directory
+    while building with a parallel make.
+  Use approved/supported Android method to check for NEON, use Linux/POSIX
+    1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
+    library calls (ported from libpng15).
+
+Version 1.6.1beta02 [February 19, 2013]
+  Use parentheses more consistently in "#if defined(MACRO)" tests.
+  Folded long lines.
+  Reenabled code to allow zero length PLTE chunks for MNG.
+
+Version 1.6.1beta03 [February 22, 2013]
+  Fixed ALIGNED_MEMORY support.
+  Added a new configure option:
+    --enable-arm-neon=always will stop the run-time checks. New checks
+    within arm/arm_init.c will cause the code not to be compiled unless
+    __ARM_NEON__ is set. This should make it fail safe (if someone asks
+    for it on then the build will fail if it can't be done.)
+  Updated the INSTALL document.
+
+Version 1.6.1beta04 [February 27, 2013]
+  Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES.
+  Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC.
+  Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble
+    with CRLF line endings.
+
+Version 1.6.1beta05 [March 1, 2013]
+  Avoid a possible memory leak in contrib/gregbook/readpng.c
+
+Version 1.6.1beta06 [March 4, 2013]
+  Better documentation of unknown handling API interactions.
+  Corrected Android builds and corrected libpng.vers with symbol
+    prefixing.  It also makes those tests compile and link on Android.
+  Added an API png_set_option() to set optimization options externally,
+    providing an alternative and general solution for the non-portable
+    run-time tests used by the ARM Neon code, using the PNG_ARM_NEON option.
+  The order of settings vs options in pnglibconf.h is reversed to allow
+    settings to depend on options and options can now set (or override) the
+    defaults for settings.
+
+Version 1.6.1beta07 [March 7, 2013]
+  Corrected simplified API default gamma for color-mapped output, added
+    a flag to change default. In 1.6.0 when the simplified API was used
+    to produce color-mapped output from an input image with no gamma
+    information the gamma assumed for the input could be different from
+    that assumed for non-color-mapped output.  In particular 16-bit depth
+    input files were assumed to be sRGB encoded, whereas in the 'direct'
+    case they were assumed to have linear data.  This was an error.  The
+    fix makes the simplified API treat all input files the same way and
+    adds a new flag to the png_image::flags member to allow the
+    application/user to specify that 16-bit files contain sRGB data
+    rather than the default linear.
+  Fixed bugs in the pngpixel and makepng test programs.
+
+Version 1.6.1beta08 [March 7, 2013]
+  Fixed CMakelists.txt to allow building a single variant of the library
+    (Claudio Bley):
+  Introduced a PNG_LIB_TARGETS variable that lists all activated library
+    targets.  It is an error if this variable ends up empty, ie. you have
+    to build at least one library variant.
+  Made the *_COPY targets only depend on library targets actually being build.
+  Use PNG_LIB_TARGETS to unify a code path.
+  Changed the CREATE_SYMLINK macro to expect the full path to a file as the
+    first argument. When symlinking the filename component of that path is
+    determined and used as the link target.
+  Use copy_if_different in the CREATE_SYMLINK macro.
+
+Version 1.6.1beta09 [March 13, 2013]
+  Eliminated two warnings from the Intel C compiler. The warnings are
+    technically valid, although a reasonable treatment of division would
+    show it to be incorrect.
+
+Version 1.6.1rc01 [March 21, 2013]
+  No changes.
+
+Version 1.6.1 [March 28, 2013]
+  No changes.
+
+Version 1.6.2beta01 [April 14, 2013]
+  Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling.
+  Fixed incorrect warning of excess deflate data. End condition - the
+    warning would be produced if the end of the deflate stream wasn't read
+    in the last row.  The warning is harmless.
+  Corrected the test on user transform changes on read. It was in the
+    png_set of the transform function, but that doesn't matter unless the
+    transform function changes the rowbuf size, and that is only valid if
+    transform_info is called.
+  Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c
+    (Flavio Medeiros).
+  Corrected length written to uncompressed iTXt chunks (Samuli Suominen).
+    Bug was introduced in libpng-1.6.0.
+
+Version 1.6.2rc01 [April 18, 2013]
+  Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length
+    written by libpng-1.6.0 and 1.6.1.
+  Disallow storing sRGB information when the sRGB is not supported.
+
+Version 1.6.2rc02 [April 18, 2013]
+  Merge pngtest.c with libpng-1.7.0
+
+Version 1.6.2rc03 [April 22, 2013]
+  Trivial spelling cleanup.
+
+Version 1.6.2rc04 and 1.6.2rc05 [omitted]
+
+Version 1.6.2rc06 [April 24, 2013]
+  Reverted to version 1.6.2rc03.  Recent changes to arm/neon support
+    have been ported to libpng-1.7.0beta09 and will reappear in version
+    1.6.3beta01.
+
+Version 1.6.2 [April 25, 2013]
+  No changes.
+
+Version 1.6.3beta01 [April 25, 2013]
+  Revised stack marking in arm/filter_neon.S and configure.ac.
+  Ensure that NEON filter stuff is completely disabled when switched 'off'.
+    Previously the ARM NEON specific files were still built if the option
+    was switched 'off' as opposed to being explicitly disabled.
+
+Version 1.6.3beta02 [April 26, 2013]
+  Test for 'arm*' not just 'arm' in the host_cpu configure variable.
+  Rebuilt the configure scripts.
+
+Version 1.6.3beta03 [April 30, 2013]
+  Expanded manual paragraph about writing private chunks, particularly
+    the need to call png_set_keep_unknown_chunks() when writing them.
+  Avoid dereferencing NULL pointer possibly returned from
+    png_create_write_struct() (Andrew Church).
+
+Version 1.6.3beta05 [May 9, 2013]
+  Calculate our own zlib windowBits when decoding rather than trusting the
+    CMF bytes in the PNG datastream.
+  Added an option to force maximum window size for inflating, which was
+    the behavior of libpng15 and earlier, via a new PNG_MAXIMUM_INFLATE_WINDOW
+    option for png_set_options().
+  Added png-fix-itxt and png-fix-too-far-back to the built programs and
+    removed warnings from the source code and timepng that are revealed as
+    a result.
+  Detect wrong libpng versions linked to png-fix-too-far-back, which currently
+    only works with libpng versions that can be made to reliably fail when
+    the deflate data contains an out-of-window reference.  This means only
+    1.6 and later.
+  Fixed gnu issues: g++ needs a static_cast, gcc 4.4.7 has a broken warning
+    message which it is easier to work round than ignore.
+  Updated contrib/pngminus/pnm2png.c (Paul Stewart):
+    Check for EOF
+    Ignore "#" delimited comments in input file to pnm2png.c.
+    Fixed whitespace handling
+    Added a call to png_set_packing()
+    Initialize dimension values so if sscanf fails at least we have known
+      invalid values.
+  Attempt to detect configuration issues with png-fix-too-far-back, which
+    requires both the correct libpng and the correct zlib to function
+    correctly.
+  Check ZLIB_VERNUM for mismatches, enclose #error in quotes
+  Added information in the documentation about problems with and fixes for
+    the bad CRC and bad iTXt chunk situations.
+
+Version 1.6.3beta06 [May 12, 2013]
+  Allow contrib/pngminus/pnm2png.c to compile without WRITE_INVERT and
+    WRITE_PACK supported (writes error message that it can't read P1 or
+    P4 PBM files).
+  Improved png-fix-too-far-back usage message, added --suffix option.
+  Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
+    right zlib header files.
+  Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
+
+Version 1.6.3beta07 [June 8, 2013]
+  Removed a redundant test in png_set_IHDR().
+  Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt)
+  Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
+  Enclose the prototypes for the simplified write API in
+    #ifdef PNG_STDIO_SUPPORTED/#endif
+  Make ARM NEON support work at compile time (not just configure time).
+    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
+    using a compiler that compiles for multiple architectures at one time.
+  Removed PNG_FILTER_OPTIMIZATIONS and PNG_ARM_NEON_SUPPORTED from
+    pnglibconf.h, allowing more of the decisions to be made internally
+    (pngpriv.h) during the compile.  Without this, symbol prefixing is broken
+    under certain circumstances on ARM platforms.  Now only the API parts of
+    the optimizations ('check' vs 'api') are exposed in the public header files
+    except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the
+    decision about whether or not to use the optimizations.
+  Protect symbol prefixing against CC/CPPFLAGS/CFLAGS usage.
+    Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test
+    on __ARM_NEON__ from configure time to compile time.  This breaks symbol
+    prefixing because the definition of the special png_init_filter_functions
+    call was hidden at configure time if the relevant compiler arguments are
+    passed in CFLAGS as opposed to CC.  This change attempts to avoid all
+    the confusion that would result by declaring the init function even when
+    it is not used, so that it will always get prefixed.
+
+Version 1.6.3beta08 [June 18, 2013]
+  Revised libpng.3 so that "doclifter" can process it.
+
+Version 1.6.3beta09 [June 27, 2013]
+  Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
+    as parameters for png_set_gamma().  These have been available since
+    libpng-1.5.4.
+  Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
+    to check all compressed chunks known to libpng.
+
+Version 1.6.3beta10 [July 5, 2013]
+  Updated documentation to show default behavior of benign errors correctly.
+  Only compile ARM code when PNG_READ_SUPPORTED is defined.
+  Fixed undefined behavior in contrib/tools/pngfix.c and added new strip
+    option. pngfix relied on undefined behavior and even a simple change from
+    gcc to g++ caused it to fail.  The new strip option 'unsafe' has been
+    implemented and is the default if --max is given.  Option names have
+    been clarified, with --strip=transform now stripping the bKGD chunk,
+    which was stripped previously with --strip=unused.
+  Added all documented chunk types to pngpriv.h
+  Unified pngfix.c source with libpng17.
+
+Version 1.6.3rc01 [July 11, 2013]
+  No changes.
+
+Version 1.6.3 [July 18, 2013]
+  Revised manual about changes in iTXt chunk handling made in libpng-1.6.0.
+  Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings
+    may be erroneously issued by code-checking applications.
+
+Version 1.6.4beta01 [August 21, 2013]
+  Added information about png_set_options() to the manual.
+  Delay calling png_init_filter_functions() until a row with nonzero filter
+    is found.
+
+Version 1.6.4beta02 [August 30, 2013]
+  Fixed inconsistent conditional compilation of png_chunk_unknown_handling()
+    prototype, definition, and usage.  Made it depend on
+    PNG_HANDLE_AS_UNKNOWN_SUPPORTED everywhere.
+
+Version 1.6.4rc01 [September 5, 2013]
+  No changes.
+
+Version 1.6.4 [September 12, 2013]
+  No changes.
+
+Version 1.6.5 [September 14, 2013]
+  Removed two stray lines of code from arm/arm_init.c.
+
+Version 1.6.6 [September 16, 2013]
+  Removed two stray lines of code from arm/arm_init.c, again.
+
+Version 1.6.7beta01 [September 30, 2013]
+  Revised unknown chunk code to correct several bugs in the NO_SAVE_/NO_WRITE
+    combination
+  Allow HANDLE_AS_UNKNOWN to work when other options are configured off. Also
+    fixed the pngminim makefiles to work when $(MAKEFLAGS) contains stuff
+    which terminates the make options (as by default in recent versions of
+    Gentoo).
+  Avoid up-cast warnings in pngvalid.c. On ARM the alignment requirements of
+    png_modifier are greater than that of png_store and as a consequence
+    compilation of pngvalid.c results in a warning about increased alignment
+    requirements because of the bare cast to (png_modifier*). The code is safe,
+    because the pointer is known to point to a stack allocated png_modifier,
+    but this change avoids the warning.
+  Fixed default behavior of ARM_NEON_API. If the ARM NEON API option was
+    compiled without the CHECK option it defaulted to on, not off.
+  Check user callback behavior in pngunknown.c. Previous versions compiled
+    if SAVE_UNKNOWN was not available but did nothing since the callback
+    was never implemented.
+  Merged pngunknown.c with 1.7 version and back ported 1.7 improvements/fixes
+
+Version 1.6.7beta02 [October 12, 2013]
+  Made changes for compatibility with automake 1.14:
+    1) Added the 'compile' program to the list of programs that must be cleaned
+       in autogen.sh
+    2) Added 'subdir-objects' which causes .c files in sub-directories to be
+       compiled such that the corresponding .o files are also in the
+       sub-directory.  This is because automake 1.14 warns that the
+       current behavior of compiling to the top level directory may be removed
+       in the future.
+    3) Updated dependencies on pnglibconf.h to match the new .o locations and
+       added all the files in contrib/libtests and contrib/tools that depend
+       on pnglibconf.h
+    4) Added 'BUILD_SOURCES = pnglibconf.h'; this is the automake recommended
+       way of handling the dependencies of sources that are machine generated;
+       unfortunately it only works if the user does 'make all' or 'make check',
+       so the dependencies (3) are still required.
+  Cleaned up (char*) casts of zlib messages. The latest version of the Intel C
+    compiler complains about casting a string literal as (char*), so copied the
+    treatment of z_const from the library code into pngfix.c
+  Simplified error message code in pngunknown. The simplification has the
+    useful side effect of avoiding a bogus warning generated by the latest
+    version of the Intel C compiler (it objects to
+    condition ? string-literal : string-literal).
+  Make autogen.sh work with automake 1.13 as well as 1.14. Do this by always
+    removing the 1.14 'compile' script but never checking for it.
+
+Version 1.6.7beta03 [October 19, 2013]
+  Added ARMv8 support (James Yu <james.yu at linaro.org>).  Added file
+    arm/filter_neon_intrinsics.c; enable with -mfpu=neon.
+  Revised pngvalid to generate size images with as many filters as it can
+    manage, limited by the number of rows.
+  Cleaned up ARM NEON compilation handling. The tests are now in pngpriv.h
+    and detect the broken GCC compilers.
+
+Version 1.6.7beta04 [October 26, 2013]
+  Allow clang derived from older GCC versions to use ARM intrinsics. This
+    causes all clang builds that use -mfpu=neon to use the intrinsics code,
+    not the assembler code.  This has only been tested on iOS 7. It may be
+    necessary to exclude some earlier clang versions but this seems unlikely.
+  Changed NEON implementation selection mechanism. This allows assembler
+    or intrinsics to be turned on at compile time during the build by defining
+    PNG_ARM_NEON_IMPLEMENTATION to the correct value (2 or 1).  This macro
+    is undefined by default and the build type is selected in pngpriv.h.
+
+Version 1.6.7rc01 [November 2, 2013]
+  No changes.
+
+Version 1.6.7rc02 [November 7, 2013]
+  Fixed #include in filter_neon_intrinsics.c and ctype macros. The ctype char
+    checking macros take an unsigned char argument, not a signed char.
+
+Version 1.6.7 [November 14, 2013]
+  No changes.
+
+Version 1.6.8beta01 [November 24, 2013]
+  Moved prototype for png_handle_unknown() in pngpriv.h outside of
+    the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
+  Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
+  Conditionally compile some unused functions reported by -Wall in
+    pngminim.
+  Fixed 'minimal' builds. Various obviously useful minimal configurations
+    don't build because of missing contrib/libtests test programs and
+    overly complex dependencies in scripts/pnglibconf.dfa. This change
+    adds contrib/conftest/*.dfa files that can be used in automatic build
+    scripts to ensure that these configurations continue to build.
+  Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder.
+  Fixed pngvalid 'fail' function declaration on the Intel C Compiler.
+    This reverts to the previous 'static' implementation and works round
+    the 'unused static function' warning by using PNG_UNUSED().
+
+Version 1.6.8beta02 [November 30, 2013]
+  Removed or marked PNG_UNUSED some harmless "dead assignments" reported
+    by clang scan-build.
+  Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
+    to '"%s" m' to improve portability among compilers.
+  Changed png_free_default() to free() in pngtest.c
+
+Version 1.6.8rc01 [December 12, 2013]
+  Tidied up pngfix inits and fixed pngtest no-write builds.
+
+Version 1.6.8rc02 [December 14, 2013]
+  Handle zero-length PLTE chunk or NULL palette with png_error()
+    instead of png_chunk_report(), which by default issues a warning
+    rather than an error, leading to later reading from a NULL pointer
+    (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
+    and VU#650142.  Libpng-1.6.1 through 1.6.7 are vulnerable.
+    Libpng-1.6.0 and earlier do not have this bug.
+
+Version 1.6.8 [December 19, 2013]
+  No changes.
+
+Version 1.6.9beta01 [December 26, 2013]
+  Bookkeeping: Moved functions around (no changes). Moved transform
+    function definitions before the place where they are called so that
+    they can be made static. Move the intrapixel functions and the
+    grayscale palette builder out of the png?tran.c files. The latter
+    isn't a transform function and is no longer used internally, and the
+    former MNG specific functions are better placed in pngread/pngwrite.c
+  Made transform implementation functions static. This makes the internal
+    functions called by png_do_{read|write}_transformations static. On an
+    x86-64 DLL build (Gentoo Linux) this reduces the size of the text
+    segment of the DLL by 1208 bytes, about 0.6%. It also simplifies
+    maintenance by removing the declarations from pngpriv.h and allowing
+    easier changes to the internal interfaces.
+  Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69
+    in the tar distributions.
+
+Version 1.6.9beta02 [January 1, 2014]
+  Added checks for libpng 1.5 to pngvalid.c.  This supports the use of
+    this version of pngvalid in libpng 1.5
+  Merged with pngvalid.c from libpng-1.7 changes to create a single
+    pngvalid.c
+  Removed #error macro from contrib/tools/pngfix.c (Thomas Klausner).
+  Merged pngrio.c, pngtrans.c, pngwio.c, and pngerror.c with libpng-1.7.0
+  Merged libpng-1.7.0 changes to make no-interlace configurations work
+    with test programs.
+  Revised pngvalid.c to support libpng 1.5, which does not support the
+    PNG_MAXIMUM_INFLATE_WINDOW option, so #define it out when appropriate in
+    pngvalid.c
+  Allow unversioned links created on install to be disabled in configure.
+    In configure builds 'make install' changes/adds links like png.h
+    and libpng.a to point to the newly installed, versioned, files (e.g.
+    libpng17/png.h and libpng17.a). Three new configure options and some
+    rearrangement of Makefile.am allow creation of these links to be disabled.
+
+Version 1.6.9beta03 [January 10, 2014]
+  Removed potentially misleading warning from png_check_IHDR().
+
+Version 1.6.9beta04 [January 20, 2014]
+  Updated scripts/makefile.* to use CPPFLAGS (Cosmin).
+  Added clang attribute support (Cosmin).
+
+Version 1.6.9rc01 [January 28, 2014]
+  No changes.
+
+Version 1.6.9rc02 [January 30, 2014]
+  Quiet an uninitialized memory warning from VC2013 in png_get_png().
+
+Version 1.6.9 [February 6, 2014]
+
+Version 1.6.10beta01 [February 9, 2014]
+  Backported changes from libpng-1.7.0beta30 and beta31:
+  Fixed a large number of instances where PNGCBAPI was omitted from
+    function definitions.
+  Added pngimage test program for png_read_png() and png_write_png()
+    with two new test scripts.
+  Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling
+    png_set_packing() in png_read_png().
+  Fixed combination of ~alpha with shift. On read invert alpha, processing
+    occurred after shift processing, which causes the final values to be
+    outside the range that should be produced by the shift. Reversing the
+    order on read makes the two transforms work together correctly and mirrors
+    the order used on write.
+  Do not read invalid sBIT chunks. Previously libpng only checked sBIT
+    values on write, so a malicious PNG writer could therefore cause
+    the read code to return an invalid sBIT chunk, which might lead to
+    application errors or crashes.  Such chunks are now skipped (with
+    chunk_benign_error).
+  Make png_read_png() and png_write_png() prototypes in png.h depend
+    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
+  Support builds with unsupported PNG_TRANSFORM_* values.  All of the
+    PNG_TRANSFORM_* values are always defined in png.h and, because they
+    are used for both read and write in some cases, it is not reliable
+    to #if out ones that are totally unsupported. This change adds error
+    detection in png_read_image() and png_write_image() to do a
+    png_app_error() if the app requests something that cannot be done
+    and it adds corresponding code to pngimage.c to handle such options
+    by not attempting to test them.
+
+Version 1.6.10beta02 [February 23, 2014]
+  Moved redefines of png_error(), png_warning(), png_chunk_error(),
+    and png_chunk_warning() from pngpriv.h to png.h to make them visible
+    to libpng-calling applications.
+  Moved OS dependent code from arm/arm_init.c, to allow the included
+    implementation of the ARM NEON discovery function to be set at
+    build-time and provide sample implementations from the current code in the
+    contrib/arm-neon subdirectory. The __linux__ code has also been changed to
+    compile and link on Android by using /proc/cpuinfo, and the old linux code
+    is in contrib/arm-neon/linux-auxv.c.  The new code avoids POSIX and Linux
+    dependencies apart from opening /proc/cpuinfo and is C90 compliant.
+  Check for info_ptr == NULL early in png_read_end() so we don't need to
+    run all the png_handle_*() and depend on them to return if info_ptr == NULL.
+    This improves the performance of png_read_end(png_ptr, NULL) and makes
+    it more robust against future programming errors.
+  Check for __has_extension before using it in pngconf.h, to
+    support older Clang versions (Jeremy Sequoia).
+  Treat CRC error handling with png_set_crc_action(), instead of with
+    png_set_benign_errors(), which has been the case since libpng-1.6.0beta18.
+  Use a user warning handler in contrib/gregbook/readpng2.c instead of default,
+    so warnings will be put on stderr even if libpng has CONSOLE_IO disabled.
+  Added png_ptr->process_mode = PNG_READ_IDAT_MODE in png_push_read_chunk
+    after recognizing the IDAT chunk, which avoids an infinite loop while
+    reading a datastream whose first IDAT chunk is of zero-length.
+    This fixes CERT VU#684412 and CVE-2014-0333.
+  Don't recognize known sRGB profiles as sRGB if they have been hacked,
+    but don't reject them and don't issue a copyright violation warning.
+
+Version 1.6.10beta03 [February 25, 2014]
+  Moved some documentation from png.h to libpng.3 and libpng-manual.txt
+  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
+
+Version 1.6.10rc01 [February 27, 2014]
+  Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS
+    and PNG_USR_CONFIG -> PNG_USER_CONFIG).
+
+Version 1.6.10rc02 [February 28, 2014]
+  Removed unreachable return statement after png_chunk_error()
+    in pngrutil.c
+
+Version 1.6.10rc03 [March 4, 2014]
+  Un-deprecated png_data_freer().
+
+Version 1.6.10 [March 6, 2014]
+  No changes.
+
+Version 1.6.11beta01 [March 17, 2014]
+  Use "if (value != 0)" instead of "if (value)" consistently.
+  Changed ZlibSrcDir from 1.2.5 to 1.2.8 in projects/vstudio.
+  Moved configuration information from the manual to the INSTALL file.
+
+Version 1.6.11beta02 [April 6, 2014]
+  Removed #if/#else/#endif from inside two pow() calls in pngvalid.c because
+    they were handled improperly by Portland Group's PGI-14.1 - PGI-14.3
+    when using its "__builtin_pow()" function.
+  Silence 'unused parameter' build warnings (Cosmin Truta).
+  $(CP) is now used alongside $(RM_F).  Also, use 'copy' instead of 'cp'
+    where applicable, and applied other minor makefile changes (Cosmin).
+  Don't warn about invalid dimensions exceeding user limits (Cosmin).
+  Allow an easy replacement of the default pre-built configuration
+    header with a custom header, via the make PNGLIBCONF_H_PREBUILT
+    macro (Cosmin).
+
+Version 1.6.11beta03 [April 6, 2014]
+  Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes
+    with "blocky" expansion of sub-8-bit interlaced PNG files (Eric Huss).
+  Optionally use  __builtin_bswap16() in png_do_swap().
+
+Version 1.6.11beta04 [April 19, 2014]
+  Made progressive reading of interlaced images consistent with the
+    behavior of the sequential reader and consistent with the manual, by
+    moving some code out of the PNG_READ_INTERLACING_SUPPORTED blocks. The
+    row_callback now receives the proper pass number and unexpanded rows, when
+    png_combine_row() isn't built or used, and png_set_interlace_handling()
+    is not called.
+  Allow PNG_sRGB_PROFILE_CHECKING = (-1) to mean no sRGB profile checking.
+
+Version 1.6.11beta05 [April 26, 2014]
+  Do not reject ICC V2 profiles that lack padding (Kai-Uwe Behrmann).
+  Relocated closing bracket of the sRGB profile test loop to avoid getting
+    "Not recognizing known sRGB profile that has been edited" warning for
+    ICC V2 profiles that lack the MD5 signature in the profile header.
+
+Version 1.6.11beta06 [May 19, 2014]
+  Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option().
+
+Version 1.6.11rc01 [May 27, 2014]
+  No changes.
+
+Version 1.6.11rc02 [June 3, 2014]
+  Test ZLIB_VERNUM instead of PNG_ZLIB_VERNUM in contrib/tools/pngfix.c
+
+Version 1.6.11 [June 5, 2014]
+  No changes.
+
+Version 1.6.12rc01 [June 6, 2014]
+  Relocated new code from 1.6.11beta06 in png.c to a point after the
+    declarations (Max Stepin).
+
+Version 1.6.12rc02 [June 7, 2014]
+  Changed file permissions of contrib/tools/intgamma.sh,
+    test-driver, and compile from 0644 to 0755 (Cosmin).
+
+Version 1.6.12rc03 [June 8, 2014]
+  Ensure "__has_attribute()" macro exists before trying to use it with
+    old clang compilers (MacPorts Ticket #43939).
+
+Version 1.6.12 [June 12, 2014]
+  No changes.
+
+Version 1.6.13beta01 [July 4, 2014]
+  Quieted -Wsign-compare and -Wclobber compiler warnings in
+    contrib/pngminus/*.c
+  Added "(void) png_ptr;" where needed in contrib/gregbook to quiet
+    compiler complaints about unused pointers.
+  Split a long output string in contrib/gregbook/rpng2-x.c.
+  Added "PNG_SET_OPTION" requirement for sRGB chunk support to pnglibconf.dfa,
+    Needed for write-only support (John Bowler).
+  Changed "if defined(__ARM_NEON__)" to
+    "if (defined(__ARM_NEON__) || defined(__ARM_NEON))" (James Wu).
+  Fixed clang no-warning builds: png_digit was defined but never used.
+    
+Version 1.6.13beta02 [July 21, 2014]
+  Fixed an incorrect separator ("/" should be "\") in scripts/makefile.vcwin32
+    (bug report from Wolfgang S. Kechel).  Bug was introduced in libpng-1.6.11.
+    Also fixed makefile.bc32, makefile.bor, makefile.msc, makefile.intel, and
+    makefile.tc3 similarly.
+
+Version 1.6.13beta03 [August 3, 2014]
+  Removed scripts/makefile.elf. It has not worked since libpng-1.5.0beta14
+    due to elimination of the PNG_FUNCTION_EXPORT and PNG_DATA_EXPORT
+    definitions from pngconf.h.
+  Ensure that CMakeLists.txt makes the target "lib" directory before making
+    symbolic link into it (SourceForge bug report #226 by Rolf Timmermans).
+
+Version 1.6.13beta04 [August 8, 2014]
+  Added opinion that the ECCN (Export Control Classification Number) for
+    libpng is EAR99 to the README file.
+  Eliminated use of "$<" in makefile explicit rules, when copying
+    $PNGLIBCONF_H_PREBUILT.  This does not work on some versions of make;
+    bug introduced in libpng version 1.6.11.
+
+Version 1.6.13rc01 [August 14, 2014]
+  Made "ccopts" agree with "CFLAGS" in scripts/makefile.hp* and makefile.*sunu
+
+Version 1.6.13 [August 21, 2014]
+  No changes.
+
+Version 1.6.14beta01 [September 14, 2014]
+  Guard usage of png_ptr->options with #ifdef PNG_SET_OPTION_SUPPORTED.
+  Do not build contrib/tools/pngfix.c when PNG_SETJMP_NOT_SUPPORTED,
+    to allow "make" to complete without setjmp support (bug report by
+    Claudio Fontana)
+  Add "#include <setjmp.h>" to contrib/tools/pngfix.c (John Bowler)
+
+Version 1.6.14beta02 [September 18, 2014]
+  Use nanosleep() instead of usleep() in contrib/gregbook/rpng2-x.c
+    because usleep() is deprecated.
+  Define usleep() in contrib/gregbook/rpng2-x.c if not already defined
+    in unistd.h and nanosleep() is not available; fixes error introduced
+    in libpng-1.6.13.
+  Disable floating point exception handling in pngvalid.c when
+    PNG_FLOATING_ARITHMETIC is not supported (bug report by "zootus
+    at users.sourceforge.net").
+
+Version 1.6.14beta03 [September 19, 2014]
+  Define FE_DIVBYZERO, FE_INVALID, and FE_OVERFLOW in pngvalid.c if not
+    already defined.  Revert floating point exception handling in pngvalid.c
+    to version 1.6.14beta01 behavior.
+
+Version 1.6.14beta04 [September 27, 2014]
+  Fixed incorrect handling of the iTXt compression flag in pngrutil.c
+    (bug report by Shunsaku Hirata).  Bug was introduced in libpng-1.6.0.
+
+Version 1.6.14beta05 [October 1, 2014]
+  Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
+
+Version 1.6.14beta06 [October 5, 2014]
+  Removed unused "text_len" parameter from private function png_write_zTXt().
+  Conditionally compile some code in png_deflate_claim(), when
+    PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.
+  Replaced repeated code in pngpread.c with PNG_PUSH_SAVE_BUFFER_IF_FULL.
+  Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT"
+    to pnglibconf.dfa.
+  Removed "option READ_COMPRESSED_TEXT enables READ_TEXT" from pnglibconf.dfa,
+    to make it possible to configure a libpng that supports iCCP but not TEXT.
+
+Version 1.6.14beta07 [October 7, 2014]
+  Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
+  Only mark text chunks as written after successfully writing them.
+
+Version 1.6.14rc01 [October 15, 2014]
+  Fixed some typos in comments.
+
+Version 1.6.14rc02 [October 17, 2014]
+  Changed png_convert_to_rfc_1123() to png_convert_to_rfc_1123_buffer()
+    in the manual, to reflect the change made in libpng-1.6.0.
+  Updated README file to explain that direct access to the png_struct
+    and info_struct members has not been permitted since libpng-1.5.0.
+
+Version 1.6.14 [October 23, 2014]
+  No changes.
+
+Version 1.6.15beta01 [October 29, 2014]
+  Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+  Simplified png_free_data().
+  Added missing "ptr = NULL" after some instances of png_free().
+
+Version 1.6.15beta02 [November 1, 2014]
+  Changed remaining "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+
+Version 1.6.15beta03 [November 3, 2014]
+  Added PNG_USE_ARM_NEON configuration flag (Marcin Juszkiewicz).
+
+Version 1.6.15beta04 [November 4, 2014]
+  Removed new PNG_USE_ARM_NEON configuration flag and made a one-line
+    revision to configure.ac to support ARM on aarch64 instead (John Bowler).
+
+Version 1.6.15beta05 [November 5, 2014]
+  Use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING in
+    example.c, pngtest.c, and applications in the contrib directory.
+  Fixed an out-of-range read in png_user_version_check() (Bug report from
+    Qixue Xiao, CVE-2015-8540).
+  Simplified and future-proofed png_user_version_check().
+  Fixed GCC unsigned int->float warnings. Various versions of GCC
+    seem to generate warnings when an unsigned value is implicitly
+    converted to double. This is probably a GCC bug but this change
+    avoids the issue by explicitly converting to (int) where safe.
+  Free all allocated memory in pngimage. The file buffer cache was left
+    allocated at the end of the program, harmless but it causes memory
+    leak reports from clang.
+  Fixed array size calculations to avoid warnings. At various points
+    in the code the number of elements in an array is calculated using
+    sizeof.  This generates a compile time constant of type (size_t) which
+    is then typically assigned to an (unsigned int) or (int). Some versions
+    of GCC on 64-bit systems warn about the apparent narrowing, even though
+    the same compiler does apparently generate the correct, in-range,
+    numeric constant.  This adds appropriate, safe, casts to make the
+    warnings go away.
+
+Version 1.6.15beta06 [November 6, 2014]
+  Reverted use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING
+    in the manual, example.c, pngtest.c, and applications in the contrib
+    directory.  It was incorrect advice.
+
+Version 1.6.15beta07 [November 7, 2014]
+  Removed #ifdef PNG_16BIT_SUPPORTED/#endif around png_product2(); it is
+    needed by png_reciprocal2().
+  Added #ifdef PNG_16BIT_SUPPORTED/#endif around png_log16bit() and
+    png_do_swap().
+  Changed all "#endif /* PNG_FEATURE_SUPPORTED */" to "#endif /* FEATURE */"
+
+Version 1.6.15beta08 [November 8, 2014]
+  More housecleaning in *.h
+
+Version 1.6.15rc01 [November 13, 2014]
+
+Version 1.6.15rc02 [November 14, 2014]
+  The macros passed in the command line to Borland make were ignored if
+    similarly-named macros were already defined in makefiles. This behavior
+    is different from POSIX make and other make programs.  Surround the
+    macro definitions with ifndef guards (Cosmin).
+
+Version 1.6.15rc03 [November 16, 2014]
+  Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in scripts/makefile.vcwin32.
+  Removed the obsolete $ARCH variable from scripts/makefile.darwin.
+
+Version 1.6.15 [November 20, 2014]
+  No changes.
+
+Version 1.6.16beta01 [December 14, 2014]
+  Added ".align 2" to arm/filter_neon.S to support old GAS assemblers that
+    don't do alignment correctly.
+  Revised Makefile.am and scripts/symbols.dfn to work with MinGW/MSYS
+    (Bob Friesenhahn).
+
+Version 1.6.16beta02 [December 15, 2014]
+  Revised Makefile.am and scripts/*.dfn again to work with MinGW/MSYS;
+    renamed scripts/*.dfn to scripts/*.c (John Bowler).
+
+Version 1.6.16beta03 [December 21, 2014]
+  Quiet a "comparison always true" warning in pngstest.c (John Bowler).
+
+Version 1.6.16rc01 [December 21, 2014]
+  Restored a test on width that was removed from png.c at libpng-1.6.9
+    (Bug report by Alex Eubanks, CVE-2015-0973).
+
+Version 1.6.16rc02 [December 21, 2014]
+  Undid the update to pngrutil.c in 1.6.16rc01.
+
+Version 1.6.16rc03 [December 21, 2014]
+  Fixed an overflow in png_combine_row() with very wide interlaced images
+    (Bug report and fix by John Bowler, CVE-2014-9495).
+
+Version 1.6.16 [December 22, 2014]
+  No changes.
+
+Version 1.6.17beta01 [January 29, 2015]
+  Removed duplicate PNG_SAFE_LIMITS_SUPPORTED handling from pngconf.h
+  Corrected the width limit calculation in png_check_IHDR().
+  Removed user limits from pngfix. Also pass NULL pointers to
+    png_read_row to skip the unnecessary row de-interlace stuff.
+  Added testing of png_set_packing() to pngvalid.c
+  Regenerated configure scripts in the *.tar distributions with libtool-2.4.4
+  Implement previously untested cases of libpng transforms in pngvalid.c
+  Fixed byte order in png_do_read_filler() with 16-bit input. Previously
+    the high and low bytes of the filler, from png_set_filler() or from
+    png_set_add_alpha(), were read in the wrong order.
+  Made the check for out-of-range values in png_set_tRNS() detect
+    values that are exactly 2^bit_depth, and work on 16-bit platforms.
+  Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
+  Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
+    pngset.c to avoid warnings about dead code.
+  Added "& 0xff" to many instances of expressions that are typecast
+    to (png_byte), to avoid Coverity warnings.
+
+Version 1.6.17beta02 [February 7, 2015]
+  Work around one more Coverity-scan dead-code warning.
+  Do not build png_product2() when it is unused.
+
+Version 1.6.17beta03 [February 17, 2015]
+  Display user limits in the output from pngtest.
+  Eliminated the PNG_SAFE_LIMITS macro and restored the 1-million-column
+    and 1-million-row default limits in pnglibconf.dfa, that can be reset
+    by the user at build time or run time.  This provides a more robust
+    defense against DOS and as-yet undiscovered overflows.
+
+Version 1.6.17beta04 [February 21, 2015]
+  Added PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED macro, on by default.
+  Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
+  Rebuilt configure scripts with automake-1.15 and libtool-2.4.6
+
+Version 1.6.17beta05 [February 25, 2015]
+  Restored compiling of png_reciprocal2 with PNG_NO_16BIT.
+
+Version 1.6.17beta06 [February 27, 2015]
+  Moved png_set_filter() prototype into a PNG_WRITE_SUPPORTED block
+    of png.h.
+  Avoid runtime checks when converting integer to png_byte with
+    Visual Studio (Sergey Kosarevsky)
+
+Version 1.6.17rc01 [March 4, 2015]
+  No changes.
+
+Version 1.6.17rc02 [March 9, 2015]
+  Removed some comments that the configure script did not handle
+    properly from scripts/pnglibconf.dfa and pnglibconf.h.prebuilt.
+  Free the unknown_chunks structure even when it contains no data.
+
+Version 1.6.17rc03 [March 12, 2015]
+  Updated CMakeLists.txt to add OSX framework, change YES/NO to ON/OFF
+    for consistency, and remove some useless tests (Alexey Petruchik).
+
+Version 1.6.17rc04 [March 16, 2015]
+  Remove pnglibconf.h, pnglibconf.c, and pnglibconf.out instead of
+    pnglibconf.* in "make clean" (Cosmin).
+  Fix bug in calculation of maxbits, in png_write_sBIT, introduced
+    in libpng-1.6.17beta01 (John Bowler).
+
+Version 1.6.17rc05 [March 21, 2015]
+  Define PNG_FILTER_* and PNG_FILTER_VALUE_* in png.h even when WRITE
+    is not supported (John Bowler).  This fixes an error introduced in
+    libpng-1.6.17beta06.
+  Reverted "& 0xff" additions of version 1.6.17beta01. Libpng passes
+    the Coverity scan without them.
+
+Version 1.6.17rc06 [March 23, 2015]
+  Remove pnglibconf.dfn and pnglibconf.pre with "make clean".
+  Reformatted some "&0xff" instances to "& 0xff".
+  Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
+    value was wrong.  It's not clear if this affected the final stored
+    value; in the obvious code path the upper and lower 8-bits of the
+    alpha value were identical and the alpha was truncated to 8-bits
+    rather than dividing by 257 (John Bowler).
+
+Version 1.6.17 [March 26, 2015]
+  No changes.
+
+Version 1.6.18beta01 [April 1, 2015]
+  Removed PNG_SET_CHUNK_[CACHE|MALLOC]_LIMIT_SUPPORTED macros.  They
+    have been combined with PNG_SET_USER_LIMITS_SUPPORTED (resolves
+    bug report by Andrew Church).
+  Fixed rgb_to_gray checks and added tRNS checks to pngvalid.c.  This
+    fixes some arithmetic errors that caused some tests to fail on
+    some 32-bit platforms (Bug reports by Peter Breitenlohner [i686]
+    and Petr Gajdos [i586]).
+
+Version 1.6.18beta02 [April 26, 2015]
+  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
+    (Bug report by Viktor Szakats).
+
+Version 1.6.18beta03 [May 6, 2015]
+  Replaced "unexpected" with an integer (0xabadca11) in pngset.c
+    where a long was expected, to avoid a compiler warning when PNG_DEBUG > 1.
+  Added contrib/examples/simpleover.c, to demonstrate how to handle
+    alpha compositing of multiple images, using the "simplified API"
+    and an example PNG generation tool, contrib/examples/genpng.c
+    (John Bowler).
+
+Version 1.6.18beta04 [May 20, 2015]
+  PNG_RELEASE_BUILD replaces tests where the code depended on the build base
+    type and can be defined on the command line, allowing testing in beta
+    builds (John Bowler).
+  Avoid Coverity issue 80858 (REVERSE NULL) in pngtest.c PNG_DEBUG builds.
+  Avoid a harmless potential integer overflow in png_XYZ_from_xy() (Bug
+    report from Christopher Ferris).
+
+Version 1.6.18beta05 [May 31, 2015]
+  Backport filter selection code from libpng-1.7.0beta51, to combine
+    sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
+  Changed png_voidcast(), etc., to voidcast(), etc., in contrib/tools/pngfix.c
+    to avoid confusion with the libpng private macros.
+  Fixed old cut&paste bug in the weighted filter selection code in
+    pngwutil.c, introduced in libpng-0.95, March 1997.
+
+Version 1.6.18beta06 [June 1, 2015]
+  Removed WRITE_WEIGHTED_FILTERED code, to save a few kbytes of the
+    compiled library size. It never worked properly and as far as we can
+    tell, no one uses it. The png_set_filter_heuristics() and
+    png_set_filter_heuristics_fixed() APIs are retained but deprecated
+    and do nothing.
+
+Version 1.6.18beta07 [June 6, 2015]
+  Removed non-working progressive reader 'skip' function. This
+    function has apparently never been used. It was implemented
+    to support back-door modification of png_struct in libpng-1.4.x
+    but (because it does nothing and cannot do anything) was apparently
+    never tested (John Bowler).
+  Fixed cexcept.h in which GCC 5 now reports that one of the auto
+    variables in the Try macro needs to be volatile to prevent value
+    being lost over the setjmp (John Bowler).
+  Fixed NO_WRITE_FILTER and -Wconversion build breaks (John Bowler).
+  Fix g++ build breaks (John Bowler).
+  Quieted some Coverity issues in pngfix.c, png-fix-itxt.c, pngvalid.c,
+    pngstest.c, and pngimage.c. Most seem harmless, but png-fix-itxt
+    would only work with iTXt chunks with length 255 or less.
+  Added #ifdef's to contrib/examples programs so people don't try
+    to compile them without the minimum required support enabled
+    (suggested by Flavio Medeiros).
+
+Version 1.6.18beta08 [June 30, 2015]
+  Eliminated the final two Coverity defects (insecure temporary file
+    handling in contrib/libtests/pngstest.c; possible overflow of
+    unsigned char in contrib/tools/png-fix-itxt.c). To use the "secure"
+    file handling, define PNG_USE_MKSTEMP, otherwise "tmpfile()" will
+    be used.
+  Removed some unused WEIGHTED_FILTER macros from png.h and pngstruct.h
+
+Version 1.6.18beta09 [July 5, 2015]
+  Removed some useless typecasts from contrib/tools/png-fix-itxt.c
+  Fixed a new signed-unsigned comparison in pngrtran.c (Max Stepin).
+  Replaced arbitrary use of 'extern' with #define PNG_LINKAGE_*.  To
+    preserve API compatibility, the new defines all default to "extern"
+    (requested by Jan Nijtmans).
+
+Version 1.6.18rc01 [July 9, 2015]
+  Belatedly added Mans Rullgard and James Yu to the list of Contributing
+    Authors.
+
+Version 1.6.18rc02 [July 12, 2015]
+  Restored unused FILTER_HEURISTIC macros removed at libpng-1.6.18beta08
+    to png.h to avoid compatibility warnings.
+
+Version 1.6.18rc03 [July 15, 2015]
+  Minor changes to the man page
+
+Version 1.6.18 [July 23, 2015]
+  No changes.
+
+Version 1.6.19beta01 [July 30, 2015]
+  Updated obsolete information about the simplified API macros in the
+    manual pages (Bug report by Arc Riley).
+  Avoid potentially dereferencing NULL info_ptr in png_info_init_3().
+  Rearranged png.h to put the major sections in the same order as
+    in libpng17.
+  Eliminated unused PNG_COST_SHIFT, PNG_WEIGHT_SHIFT, PNG_COST_FACTOR, and
+    PNG_WEIGHT_FACTOR macros.
+  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
+    (Bug report by Viktor Szakats).  Several warnings remain and are
+    unavoidable, where we test for overflow.
+  Fixed potential leak of png_pixels in contrib/pngminus/pnm2png.c
+  Fixed uninitialized variable in contrib/gregbook/rpng2-x.c
+
+Version 1.6.19beta02 [August 19, 2015]
+  Moved config.h.in~ from the "libpng_autotools_files" list to the
+    "libpng_autotools_extra" list in autogen.sh because it was causing a
+    false positive for missing files (bug report by Robert C. Seacord).
+  Removed unreachable "break" statements in png.c, pngread.c, and pngrtran.c
+    to suppress clang warnings (Bug report by Viktor Szakats).
+  Fixed some bad links in the man page.
+  Changed "n bit" to "n-bit" in comments.
+  Added signed/unsigned 16-bit safety net. This removes the dubious
+    0x8000 flag definitions on 16-bit systems. They aren't supported
+    yet the defs *probably* work, however it seems much safer to do this
+    and be advised if anyone, contrary to advice, is building libpng 1.6
+    on a 16-bit system. It also adds back various switch default clauses
+    for GCC; GCC errors out if they are not present (with an appropriately
+    high level of warnings).
+  Safely convert num_bytes to a png_byte in png_set_sig_bytes() (Robert
+    Seacord).
+  Fixed the recently reported 1's complement security issue by replacing
+    the value that is illegal in the PNG spec, in both signed and unsigned
+    values, with 0. Illegal unsigned values (anything greater than or equal
+    to  0x80000000) can still pass through, but since these are not illegal
+    in ANSI-C (unlike 0x80000000 in the signed case) the checking that
+    occurs later can catch them (John Bowler).
+
+Version 1.6.19beta03 [September 26, 2015]
+  Fixed png_save_int_32 when int is not 2's complement (John Bowler).
+  Updated libpng16 with all the recent test changes from libpng17,
+    including changes to pngvalid.c to ensure that the original,
+    distributed, version of contrib/visupng/cexcept.h can be used
+    (John Bowler).
+  pngvalid contains the correction to the use of SAVE/STORE_
+    UNKNOWN_CHUNKS; a bug revealed by changes in libpng 1.7. More
+    tests contain the --strict option to detect warnings and the
+    pngvalid-standard test has been corrected so that it does not
+    turn on progressive-read. There is a separate test which does
+    that. (John Bowler)
+  Also made some signed/unsigned fixes.
+  Make pngstest error limits version specific. Splitting the machine
+    generated error structs out to a file allows the values to be updated
+    without changing pngstest.c itself. Since libpng 1.6 and 1.7 have
+    slightly different error limits this simplifies maintenance. The
+    makepngs.sh script has also been updated to more accurately reflect
+    current problems in libpng 1.7 (John Bowler).
+  Incorporated new test PNG files into make check.  tests/pngstest-*
+    are changed so that the new test files are divided into 8 groups by
+    gamma and alpha channel.  These tests have considerably better code
+    and pixel-value coverage than contrib/pngsuite; however,coverage is
+    still incomplete (John Bowler).
+  Removed the '--strict' in 1.6 because of the double-gamma-correction
+    warning, updated pngstest-errors.h for the errors detected with the
+    new contrib/testspngs PNG test files (John Bowler).
+
+Version 1.6.19beta04 [October 15, 2015]
+  Worked around rgb-to-gray issues in libpng 1.6.  The previous
+    attempts to ignore the errors in the code aren't quite enough to
+    deal with the 'channel selection' encoding added to libpng 1.7; abort.
+    pngvalid.c is changed to drop this encoding in prior versions.
+  Fixed 'pow' macros in pngvalid.c. It is legal for 'pow' to be a
+    macro, therefore the argument list cannot contain preprocessing
+    directives.  Make sure pow is a function where this happens. This is
+    a minimal safe fix, the issue only arises in non-performance-critical
+    code (bug report by Curtis Leach, fix by John Bowler).
+  Added sPLT support to pngtest.c
+
+Version 1.6.19rc01 [October 23, 2015]
+  No changes.
+
+Version 1.6.19rc02 [October 31, 2015]
+  Prevent setting or writing over-length PLTE chunk (Cosmin Truta).
+  Silently truncate over-length PLTE chunk while reading.
+  Libpng incorrectly calculated the output rowbytes when the application
+    decreased either the number of channels or the bit depth (or both) in
+    a user transform.  This was safe; libpng overallocated buffer space
+   (potentially by quite a lot; up to 4 times the amount required) but,
+   from 1.5.4 on, resulted in a png_error (John Bowler).
+
+Version 1.6.19rc03 [November 3, 2015]
+  Fixed some inconsequential cut-and-paste typos in png_set_cHRM_XYZ_fixed().
+  Clarified COPYRIGHT information to state explicitly that versions
+    are derived from previous versions.
+  Removed much of the long list of previous versions from png.h and
+    libpng.3.
+
+Version 1.6.19rc04 [November 5, 2015]
+  Fixed new bug with CRC error after reading an over-length palette
+    (bug report by Cosmin Truta) (CVE-2015-8126).
+
+Version 1.6.19 [November 12, 2015]
+  Cleaned up coding style in png_handle_PLTE().
+
+Version 1.6.20beta01 [November 20, 2015]
+  Avoid potential pointer overflow/underflow in png_handle_sPLT() and
+    png_handle_pCAL() (Bug report by John Regehr).
+
+Version 1.6.20beta02 [November 23, 2015]
+  Fixed incorrect implementation of png_set_PLTE() that uses png_ptr
+    not info_ptr, that left png_set_PLTE() open to the CVE-2015-8126
+    vulnerability.  Fixes CVE-2015-8472.
+
+Version 1.6.20beta03 [November 24, 2015]
+  Backported tests from libpng-1.7.0beta69.
+
+Version 1.6.20rc01 [November 26, 2015]
+  Fixed an error in handling of bad zlib CMINFO field in pngfix, found by
+    American Fuzzy Lop, reported by Brian Carpenter.  inflate() doesn't
+    immediately fault a bad CMINFO field; instead a 'too far back' error
+    happens later (at least some times).  pngfix failed to limit CMINFO to
+    the allowed values but then assumed that window_bits was in range,
+    triggering an assert. The bug is mostly harmless; the PNG file cannot
+    be fixed.
+
+Version 1.6.20rc02 [November 29, 2015]
+  In libpng 1.6 zlib initialization was changed to use the window size
+    in the zlib stream, not a fixed value. This causes some invalid images,
+    where CINFO is too large, to display 'correctly' if the rest of the
+    data is valid.  This provides a workaround for zlib versions where the
+    error arises (ones that support the API change to use the window size
+    in the stream).
+
+Version 1.6.20 [December 3, 2015]
+  No changes.
+
+Version 1.6.21beta01 [December 11, 2015]
+  Fixed syntax "$(command)" in tests/pngstest that some shells other than
+    bash could not parse (Bug report by Nelson Beebe). Use `command` instead.
+
+Version 1.6.21beta02 [December 14, 2015]
+  Moved png_check_keyword() from pngwutil.c to pngset.c
+  Removed LE/BE dependencies in pngvalid, to 'fix' the current problem
+    in the BigEndian tests by not testing it, making the BE code the same 
+    as the LE version.
+  Fixes to pngvalid for various reduced build configurations (eliminate unused
+    statics) and a fix for the case in rgb_to_gray when the digitize option
+    reduces graylo to 0, producing a large error.
+
+Version 1.6.21beta03 [December 18, 2015]
+  Widened the 'limit' check on the internally calculated error limits in
+    the 'DIGITIZE' case (the code used prior to 1.7 for rgb_to_gray error
+    checks) and changed the check to only operate in non-release builds
+    (base build type not RC or RELEASE.)
+  Fixed undefined behavior in pngvalid.c, undefined because
+    (png_byte) << shift is undefined if it changes the signed bit
+    (because png_byte is promoted to int). The libpng exported functions
+    png_get_uint_32 and png_get_uint_16 handle this. (Bug reported by
+    David Drysdale as a result of reports from UBSAN in clang 3.8).
+  This changes pngvalid to use BE random numbers; this used to produce
+    errors but these should not be fixed as a result of the previous changes.
+
+Version 1.6.21rc01 [January 4, 2016]
+  In projects/vstudio, combined readme.txt and WARNING into README.txt
+
+Version 1.6.21rc02 [January 7, 2016]
+  Relocated assert() in contrib/tools/pngfix.c, bug found by American
+    Fuzzy Lop, reported by Brian Carpenter.
+  Marked 'limit' UNUSED in transform_range_check().  This only affects
+    release builds.
+
+Version 1.6.21 [January 15, 2016]
+  Worked around a false-positive Coverity issue in pngvalid.c.
+
+Version 1.6.22beta01 [January 23, 2016]
+  Changed PNG_USE_MKSTEMP to __COVERITY__ to select alternate
+    "tmpfile()" implementation in contrib/libtests/pngstest.c
+  Fixed NO_STDIO build of pngunknown.c to skip calling png_init_io()
+    if there is no stdio.h support.
+  Added a png_image_write_to_memory() API and a number of assist macros
+    to allow an application that uses the simplified API write to bypass
+    stdio and write directly to memory.
+  Added some warnings (png.h) and some check code to detect *possible*
+    overflow in the ROW_STRIDE and simplified image SIZE macros.  This
+    disallows image width/height/format that *might* overflow.  This is
+    a quiet API change that limits in-memory image size (uncompressed) to
+    less than 4GByte and image row size (stride) to less than 2GByte.
+  Revised workaround for false-positive Coverity issue in pngvalid.c.
+
+Version 1.6.22beta02 [February 8, 2016]
+  Only use exit(77) in configure builds.
+  Corrected error in PNG_IMAGE_PNG_SIZE_MAX. This new macro underreported
+    the palette size because it failed to take into account that the memory
+    palette has to be expanded to full RGB when it is written to PNG.
+  Updated CMakeLists.txt, added supporting scripts/gen*.cmake.in
+    and test.cmake.in (Roger Leigh).
+  Relaxed limit checks on gamma values in pngrtran.c. As suggested in
+    the comments gamma values outside the range currently permitted
+    by png_set_alpha_mode are useful for HDR data encoding.  These values
+    are already permitted by png_set_gamma so it is reasonable caution to
+    extend the png_set_alpha_mode range as HDR imaging systems are starting
+    to emerge.
+
+Version 1.6.22beta03 [March 9, 2016]
+  Added a common-law trademark notice and export control information
+    to the LICENSE file, png.h, and the man page.
+  Restored "& 0xff" in png_save_uint_16() and png_save_uint_32() that
+    were accidentally removed from libpng-1.6.17. 
+  Changed PNG_INFO_cHNK and PNG_FREE_cHNK from 0xnnnn to 0xnnnnU in png.h
+    (Robert C. Seacord).
+  Removed dubious "#if INT_MAX" test from png.h that was added to
+    libpng-1.6.19beta02 (John Bowler).
+  Add ${INCLUDES} in scripts/genout.cmake.in (Bug report by Nixon Kwok).
+  Updated LICENSE to say files in the contrib directory are not
+    necessarily under the libpng license, and that some makefiles have
+    other copyright owners.
+  Added INTEL-SSE2 support (Mike Klein and Matt Sarett, Google, Inc.).
+  Made contrib/libtests/timepng more robust.  The code no longer gives
+    up/fails on invalid PNG data, it just skips it (with error messages).
+    The code no longer fails on PNG files with data beyond IEND.  Options
+    exist to use png_read_png (reading the whole image, not by row) and, in
+    that case, to apply any of the supported transforms.  This makes for
+    more realistic testing; the decoded data actually gets used in a
+    meaningful fashion (John Bowler).
+  Fixed some misleading indentation (Krishnaraj Bhat).
+
+Version 1.6.22beta04 [April 5, 2016]
+  Force GCC compilation to C89 if needed (Dagobert Michelsen).
+  SSE filter speed improvements for bpp=3:
+    memcpy-free implementations of load3() / store3().
+    call load3() only when needed at the end of a scanline.
+
+Version 1.6.22beta05 [April 27, 2016]
+  Added PNG_FAST_FILTERS macro (defined as
+    PNG_FILTER_NONE|PNG_FILTER_SUB|PNG_FILTER_UP).
+  Various fixes for contrib/libtests/timepng.c
+  Moved INTEL-SSE code from pngpriv.h into contrib/intel/intel_sse.patch.
+  Fixed typo (missing underscore) in #define PNG_READ_16_TO_8_SUPPORTED
+    (Bug report by Y.Ohashik).
+
+Version 1.6.22beta06 [May 5, 2016]
+  Rebased contrib/intel_sse.patch.
+  Quieted two Coverity issues in contrib/libtests/timepng.c.
+  Fixed issues with scripts/genout.cmake.in (David Capello, Nixon Kwok):
+    Added support to use multiple directories in ZLIBINCDIR variable,
+    Fixed CMAKE_C_FLAGS with multiple values when genout is compiled on MSVC,
+    Fixed pnglibconf.c compilation on OS X including the sysroot path.
+
+Version 1.6.22rc01 [May 14, 2016]
+  No changes.
+
+Version 1.6.22rc02 [May 16, 2016]
+  Removed contrib/timepng from default build; it does not build on platforms
+    that don't supply clock_gettime().
+
+Version 1.6.22rc03 [May 17, 2016]
+  Restored contrib/timepng to default build but check for the presence
+    of clock_gettime() in configure.ac and Makefile.am.
+
+Version 1.6.22 [May 26, 2016]
+  No changes.
+
+Version 1.6.23beta01 [May 29, 2016]
+  Stop a potential memory leak in png_set_tRNS() (Bug report by Ted Ying).
+  Fixed the progressive reader to handle empty first IDAT chunk properly
+    (patch by Timothy Nikkel).  This bug was introduced in libpng-1.6.0 and
+    only affected the libpng16 branch.
+  Added tests in pngvalid.c to check zero-length IDAT chunks in various
+    positions.  Fixed the sequential reader to handle these more robustly
+    (John Bowler).
+
+Version 1.6.23rc01 [June 2, 2016]
+  Corrected progressive read input buffer in pngvalid.c. The previous version
+    the code invariably passed just one byte at a time to libpng.  The intent
+    was to pass a random number of bytes in the range 0..511.
+  Moved sse2 prototype from pngpriv.h to contrib/intel/intel_sse.patch.
+  Added missing ")" in pngerror.c (Matt Sarrett).
+
+Version 1.6.23rc02 [June 4, 2016]
+  Fixed undefined behavior in png_push_save_buffer(). Do not call
+    memcpy() with a null source, even if count is zero (Leon Scroggins III).
+
+Version 1.6.23 [June 9, 2016]
+  Fixed bad link to RFC2083 in png.5 (Nikola Forro).
+
+Version 1.6.24beta01 [June 11, 2016]
+  Avoid potential overflow of the PNG_IMAGE_SIZE macro.  This macro
+    is not used within libpng, but is used in some of the examples.
+
+Version 1.6.24beta02 [June 23, 2016]
+  Correct filter heuristic overflow handling. This was broken when the
+    write filter code was moved out-of-line; if there is a single filter and
+    the heuristic sum overflows the calculation of the filtered line is not
+    completed.  In versions prior to 1.6 the code was duplicated in-line
+    and the check not performed, so the filter operation completed; however,
+    in the multi-filter case where the sum is performed the 'none' filter would
+    be selected if all the sums overflowed, even if it wasn't in the filter
+    list.  The fix to the first problem is simply to provide PNG_SIZE_MAX as
+    the current lmins sum value; this means the sum can never exceed it and
+    overflows silently.  A reasonable compiler that does choose to inline
+    the code will simply eliminate the sum check.
+  The fix to the second problem is to use high precision arithmetic (this is
+    implemented in 1.7), however a simple safe fix here is to chose the lowest
+    numbered filter in the list from png_set_filter (this only works if the
+    first problem is also fixed) (John Bowler).
+  Use a more efficient absolute value calculation on SSE2 (Matthieu Darbois).
+  Fixed the case where PNG_IMAGE_BUFFER_SIZE can overflow in the application
+    as a result of the application using an increased 'row_stride'; previously
+    png_image_finish_read only checked for overflow on the base calculation of
+    components.  (I.e. it checked for overflow of a 32-bit number on the total
+    number of pixel components in the output format, not the possibly padded row
+    length and not the number of bytes, which for linear formats is twice the
+    number of components.)
+  MSVC does not like '-(unsigned)', so replaced it with 0U-(unsigned)
+  MSVC does not like (uInt) = -(unsigned) (i.e. as an initializer), unless
+    the conversion is explicitly invoked by a cast.
+  Put the SKIP definition in the correct place. It needs to come after the
+    png.h include (see all the other .c files in contrib/libtests) because it
+    depends on PNG_LIBPNG_VER.
+  Removed the three compile warning options from the individual project
+    files into the zlib.props globals.  It increases the warning level from 4
+    to All and adds a list of the warnings that need to be turned off.  This is
+    semi-documentary; the intent is to tell libpng users which warnings have
+    been examined and judged non-fixable at present.  The warning about
+    structure padding is fixable, but it would be a significant change (moving
+    structure members around).
+
+Version 1.6.24beta03 [July 4, 2016]
+  Optimized absolute value calculation in filter selection, similar to
+    code in the PAETH decoder in pngrutil.c. Build with PNG_USE_ABS to
+    use this.
+  Added pngcp to the build together with a pngcp.dfa configuration test.
+  Added high resolution timing to pngcp.
+  Added "Common linking failures" section to INSTALL.
+  Relocated misplaced #endif in png.c sRGB profile checking.
+  Fixed two Coverity issues in pngcp.c.
+
+Version 1.6.24beta04 [July 8, 2016]
+  Avoid filter-selection heuristic sum calculations in cases where only one
+    filter is a candidate for selection. This trades off code size (added
+    private png_setup_*_row_only() functions) for speed.
+
+Version 1.6.24beta05 [July 13, 2016]
+  Fixed some indentation to comply with our coding style.
+  Added contrib/tools/reindent.
+
+Version 1.6.24beta06 [July 18, 2016]
+  Fixed more indentation to comply with our coding style.
+  Eliminated unnecessary tests of boolean png_isaligned() vs 0.
+
+Version 1.6.24rc01 [July 25, 2016]
+  No changes.
+
+Version 1.6.24rc02 [August 1, 2016]
+  Conditionally compile SSE2 headers in contrib/intel/intel_sse.patch
+  Conditionally compile png_decompress_chunk().
+
+Version 1.6.24rc03 [August 2, 2016]
+  Conditionally compile ARM_NEON headers in pngpriv.h
+  Updated contrib/intel/intel_sse.patch
+
+Version 1.6.24[August 4, 2016]
+  No changes.
+
+Version 1.6.25beta01 [August 12, 2016]
+  Reject oversized iCCP profile immediately.
+  Cleaned up PNG_DEBUG compile of pngtest.c.
+  Conditionally compile png_inflate().
+
+Version 1.6.25beta02 [August 18, 2016]
+  Don't install pngcp; it conflicts with pngcp in the pngtools package.
+  Minor editing of INSTALL, (whitespace, added copyright line)
+
+Version 1.6.25rc01 [August 24, 2016]
+  No changes.
+
+Version 1.6.25rc02 [August 29, 2016]
+  Added MIPS support (Mandar Sahastrabuddhe <Mandar.Sahastrabuddhe@imgtec.com>).
+  Only the UP filter is currently implemented.
+
+Version 1.6.25rc03 [August 29, 2016]
+  Rebased contrib/intel/intel_sse.patch after the MIPS implementation.
+
+Version 1.6.25rc04 [August 30, 2016]
+  Added MIPS support for SUB, AVG, and PAETH filters (Mandar Sahastrabuddhe).
+
+Version 1.6.25rc05 [August 30, 2016]
+  Rebased contrib/intel/intel_sse.patch after the MIPS implementation update..
+
+Version 1.6.25 [September 1, 2016]
+  No changes.
+
+Version 1.6.26beta01 [September 26, 2016]
+  Fixed handling zero length IDAT in pngfix (bug report by Agostino Sarubbo,
+    bugfix by John Bowler).
+  Do not issue a png_error() on read in png_set_pCAL() because png_handle_pCAL
+    has allocated memory that libpng needs to free.
+  Conditionally compile png_set_benign_errors() in pngread.c and pngtest.c
+  Issue a png_benign_error instead of a png_error on ADLER32 mismatch
+    while decoding compressed data chunks.
+  Changed PNG_ZLIB_VERNUM to ZLIB_VERNUM in pngpriv.h, pngstruct.h, and
+    pngrutil.c.
+  If CRC handling of critical chunks has been set to PNG_CRC_QUIET_USE,
+    ignore the ADLER32 checksum in the IDAT chunk as well as the chunk CRCs.
+  Issue png_benign_error() on ADLER32 checksum mismatch instead of png_error().
+  Add tests/badcrc.png and tests/badadler.png to tests/pngtest.
+  Merged pngtest.c with libpng-1.7.0beta84/pngtest.c
+
+Version 1.6.26beta02 [October 1, 2016]
+  Updated the documentation about CRC and ADLER32 handling.
+  Quieted 117 warnings from clang-3.8 in pngtrans.c, pngread.c,
+     pngwrite.c, pngunknown.c, and pngvalid.c.
+  Quieted 58 (out of 144) -Wconversion compiler warnings by changing
+    flag definitions in pngpriv.h from 0xnnnn to 0xnnnnU and trivial changes
+    in png.c, pngread.c, and pngwutil.c.
+
+Version 1.6.26beta03 [October 2, 2016]
+  Removed contrib/libtests/*.orig and *.rej that slipped into the tarballs.
+  Quieted the 86 remaining -Wconversion compiler warnings by
+    revising the png_isaligned() macro and trivial changes in png.c,
+    pngerror.c, pngget.c, pngmem.c, pngset.c, pngrtran.c, pngrutil.c,
+    pngwtran.c, pngwrite.c, and pngwutil.c.
+
+Version 1.6.26beta04 [October 3, 2016]
+  Quieted (bogus?) clang warnings about "absolute value has no effect"
+    when PNG_USE_ABS is defined.
+  Fixed offsets in contrib/intel/intel_sse.patch
+
+Version 1.6.26beta05 [October 6, 2016]
+  Changed integer constant 4294967294 to unsigned 4294967294U in pngconf.h
+    to avoid a signed/unsigned compare in the preprocessor.
+
+Version 1.6.26beta06 [October 7, 2016]
+  Use zlib-1.2.8.1 inflateValidate() instead of inflateReset2() to
+    optionally avoid ADLER32 evaluation.
+
+Version 1.6.26rc01 [October 12, 2016]
+  No changes.
+
+Version 1.6.26 [October 20, 2016]
+  Cosmetic change, "ptr != 0" to "ptr != NULL" in png.c and pngrutil.c
+  Despammed email addresses (replaced "@" with " at ").
+
+Version 1.6.27beta01 [November 2, 2016]
+  Restrict the new ADLER32-skipping to IDAT chunks.  It broke iCCP chunk
+    handling: an erroneous iCCP chunk would throw a png_error and reject the
+    entire PNG image instead of rejecting just the iCCP chunk with a warning,
+    if built with zlib-1.2.8.1.
+
+Version 1.6.27rc01 [December 27, 2016]
+  Control ADLER32 checking with new PNG_IGNORE_ADLER32 option. Fixes
+    an endless loop when handling erroneous ADLER32 checksums; bug
+    introduced in libpng-1.6.26.
+  Removed the use of a macro containing the pre-processor 'defined'
+    operator.  It is unclear whether this is valid; a macro that
+    "generates" 'defined' is not permitted, but the use of the word
+    "generates" within the C90 standard seems to imply more than simple
+    substitution of an expression itself containing a well-formed defined
+    operation.
+  Added ARM support to CMakeLists.txt (Andreas Franek).
+
+Version 1.6.27 [December 29, 2016]
+  Fixed a potential null pointer dereference in png_set_text_2() (bug report
+    and patch by Patrick Keshishian, CVE-2016-10087).
+
+Version 1.6.28rc01 [January 3, 2017]
+  Fixed arm/aarch64 detection in CMakeLists.txt (Gianfranco Costamagna).
+  Added option to Cmake build allowing a custom location of zlib to be
+    specified in a scenario where libpng is being built as a subproject
+    alongside zlib by another project (Sam Serrels).
+  Changed png_ptr->options from a png_byte to png_uint_32, to accommodate
+    up to 16 options.
+
+Version 1.6.28rc02 [January 4, 2017]
+  Added "include(GNUInstallDirs)" to CMakeLists.txt (Gianfranco Costamagna).
+  Moved SSE2 optimization code into the main libpng source directory.
+    Configure libpng with "configure --enable-intel-sse" or compile
+    libpng with "-DPNG_INTEL_SSE" in CPPFLAGS to enable it.
+
+Version 1.6.28rc03 [January 4, 2017]
+  Backed out the SSE optimization and last CMakeLists.txt to allow time for QA.
+
+Version 1.6.28 [January 5, 2017]
+  No changes.
+
+Version 1.6.29beta01 [January 12, 2017]
+  Readded "include(GNUInstallDirs)" to CMakeLists.txt (Gianfranco Costamagna).
+  Moved SSE2 optimization code into the main libpng source directory.
+    Configure libpng with "configure --enable-intel-sse" or compile
+    libpng with "-DPNG_INTEL_SSE" in CPPFLAGS to enable it.
+  Simplified conditional compilation in pngvalid.c, for AIX (Michael Felt).
+
+Version 1.6.29beta02 [February 22, 2017]
+  Avoid conditional directives that break statements in pngrutil.c (Romero
+    Malaquias)
+  The contrib/examples/pngtopng.c recovery code was in the wrong "if"
+    branches; the comments were correct.
+  Added code for PowerPC VSX optimisation (Vadim Barkov).
+
+Version 1.6.29beta03 [March 1, 2017]
+  Avoid potential overflow of shift operations in png_do_expand() (Aaron Boxer).
+  Change test ZLIB_VERNUM >= 0x1281 to ZLIB_VERNUM >= 0x1290 in pngrutil.c
+    because Solaris 11 distributes zlib-1.2.8.f that is older than 1.2.8.1,
+    as suggested in zlib FAQ, item 24.
+  Suppress clang warnings about implicit sign changes in png.c
+
+Version 1.6.29 [March 16, 2017]
+  No changes.
+
+Version 1.6.30beta01 [April 1, 2017]
+  Added missing "$(CPPFLAGS)" to the compile line for c.pic.o in
+    makefile.linux and makefile.solaris-x86 (Cosmin).
+  Revised documentation of png_get_error_ptr() in the libpng manual.
+  Silence clang -Wcomma and const drop warnings (Viktor Szakats).
+  Update Sourceforge URLs in documentation (https instead of http).
+
+Version 1.6.30beta02 [April 22, 2017]
+  Document need to check for integer overflow when allocating a pixel
+    buffer for multiple rows in contrib/gregbook, contrib/pngminus,
+    example.c, and in the manual (suggested by Jaeseung Choi). This
+    is similar to the bug reported against pngquant in CVE-2016-5735.
+  Removed reference to the obsolete PNG_SAFE_LIMITS macro in the documentation.
+
+Version 1.6.30beta03 [May 22, 2017]
+  Check for integer overflow in contrib/visupng and contrib/tools/genpng.
+  Do not double evaluate CMAKE_SYSTEM_PROCESSOR in CMakeLists.txt.
+  Test CMAKE_HOST_WIN32 instead of WIN32 in CMakeLists.txt.
+  Fix some URL in documentation.
+
+Version 1.6.30beta04 [June 7, 2017]
+  Avoid writing an empty IDAT when the last IDAT exactly fills the
+    compression buffer (bug report by Brian Baird). This bug was
+    introduced in libpng-1.6.0.
+
+Version 1.6.30rc01 [June 14, 2017]
+  No changes.
+
+Version 1.6.30rc02 [June 25, 2017]
+  Update copyright year in pnglibconf.h, make ltmain.sh executable.
+  Add a reference to the libpng.download site in README.
+
+Version 1.6.30 [June 28, 2017]
+  No changes.
+
+Version 1.6.31beta01 [July 5, 2017]
+  Guard the definition of _POSIX_SOURCE in pngpriv.h (AIX already defines it;
+    bug report by Michael Felt).
+  Revised pngpriv.h to work around failure to compile arm/filter_neon.S
+    ("typedef" directive is unrecognized by the assembler). The problem
+    was introduced in libpng-1.6.30beta01.
+  Added "Requires: zlib" to libpng.pc.in (Pieter Neerincx).
+  Added special case for FreeBSD in arm/filter_neon.S (Maya Rashish).
+
+Version 1.6.31beta02 [July 8, 2017]
+  Added instructions for disabling hardware optimizations in INSTALL.
+  Added "--enable-hardware-optimizations" configuration flag to enable
+    or disable all hardware optimizations with one flag.
+
+Version 1.6.31beta03 [July 9, 2017]
+  Updated CMakeLists.txt to add INTEL_SSE and MIPS_MSA platforms.
+  Changed "int" to "png_size_t" in intel/filter_sse2.c to prevent
+    possible integer overflow (Bug report by John Bowler).
+  Quieted "declaration after statement" warnings in intel/filter_sse2.c.
+  Added scripts/makefile-linux-opt, which has hardware optimizations enabled.
+
+Version 1.6.31beta04 [July 11, 2017]
+  Removed one of the GCC-7.1.0 'strict-overflow' warnings that result when
+    integers appear on both sides of a compare.  Worked around the others by
+    forcing the strict-overflow setting in the relevant functions to a level
+    where they are not reported (John Bowler).
+  Changed "FALL THROUGH" comments to "FALLTHROUGH" because GCC doesn't like
+    the space.
+  Worked around some C-style casts from (void*) because g++ 5.4.0 objects
+    to them.
+  Increased the buffer size for 'sprint' to pass the gcc 7.1.0 'sprint
+    overflow' check that is on by default with -Wall -Wextra.
+
+Version 1.6.31beta05 [July 13, 2017]
+  Added eXIf chunk support.
+
+Version 1.6.31beta06 [July 17, 2017]
+  Added a minimal eXIf chunk (with Orientation and FocalLengthIn35mmFilm
+    tags) to pngtest.png.
+
+Version 1.6.31beta07 [July 18, 2017]
+  Revised the eXIf chunk in pngtest.png to fix "Bad IFD1 Directory" warning.
+
+Version 1.6.31rc01 [July 19, 2017]
+  No changes.
+
+Version 1.6.31rc02 [July 25, 2017]
+  Fixed typo in example.c (png_free_image should be png_image_free) (Bug
+    report by John Smith)
+
+Version 1.6.31 [July 27, 2017]
+  No changes.
+
+Version 1.6.32beta01 [July 31, 2017]
+  Avoid possible NULL dereference in png_handle_eXIf when benign_errors
+    are allowed. Avoid leaking the input buffer "eXIf_buf".
+  Eliminated png_ptr->num_exif member from pngstruct.h and added num_exif
+    to arguments for png_get_eXIf() and png_set_eXIf().
+  Added calls to png_handle_eXIf(() in pngread.c and png_write_eXIf() in
+    pngwrite.c, and made various other fixes to png_write_eXIf().
+  Changed name of png_get_eXIF and png_set_eXIf() to png_get_eXIf_1() and
+    png_set_eXIf_1(), respectively, to avoid breaking API compatibility
+    with libpng-1.6.31.
+
+Version 1.6.32beta02 [August 1, 2017]
+  Updated contrib/libtests/pngunknown.c with eXIf chunk.
+
+Version 1.6.32beta03 [August 2, 2017]
+  Initialized btoa[] in pngstest.c
+  Stop memory leak when returning from png_handle_eXIf() with an error
+    (Bug report from the OSS-fuzz project).
+
+Version 1.6.32beta04 [August 2, 2017]
+  Replaced local eXIf_buf with info_ptr-eXIf_buf in png_handle_eXIf().
+  Update libpng.3 and libpng-manual.txt about eXIf functions.
+
+Version 1.6.32beta05 [August 2, 2017]
+  Restored png_get_eXIf() and png_set_eXIf() to maintain API compatibility.
+
+Version 1.6.32beta06 [August 2, 2017]
+  Removed png_get_eXIf_1() and png_set_eXIf_1().
+
+Version 1.6.32beta07 [August 3, 2017]
+  Check length of all chunks except IDAT against user limit to fix an
+    OSS-fuzz issue (Fixes CVE-2017-12652).
+
+Version 1.6.32beta08 [August 3, 2017]
+  Check length of IDAT against maximum possible IDAT size, accounting
+    for height, rowbytes, interlacing and zlib/deflate overhead.
+  Restored png_get_eXIf_1() and png_set_eXIf_1(), because strlen(eXIf_buf)
+    does not work (the eXIf chunk data can contain zeroes).
+
+Version 1.6.32beta09 [August 3, 2017]
+  Require cmake-2.8.8 in CMakeLists.txt. Revised symlink creation,
+    no longer using deprecated cmake LOCATION feature (Clifford Yapp).
+  Fixed five-byte error in the calculation of IDAT maximum possible size.
+  
+Version 1.6.32beta10 [August 5, 2017]
+  Moved chunk-length check into a png_check_chunk_length() private
+    function (Suggested by Max Stepin).
+  Moved bad pngs from tests to contrib/libtests/crashers
+  Moved testing of bad pngs into a separate tests/pngtest-badpngs script
+  Added the --xfail (expected FAIL) option to pngtest.c. It writes XFAIL
+    in the output but PASS for the libpng test.
+  Require cmake-3.0.2 in CMakeLists.txt (Clifford Yapp).
+  Fix "const" declaration info_ptr argument to png_get_eXIf_1() and the
+    num_exif argument to png_get_eXIf_1() (Github Issue 171).
+
+Version 1.6.32beta11 [August 7, 2017]
+  Added "eXIf" to "chunks_to_ignore[]" in png_set_keep_unknown_chunks().
+  Added huge_IDAT.png and empty_ancillary_chunks.png to testpngs/crashers.
+  Make pngtest --strict, --relax, --xfail options imply -m (multiple).
+  Removed unused chunk_name parameter from png_check_chunk_length().
+  Relocated setting free_me for eXIf data, to stop an OSS-fuzz leak.
+  Initialize profile_header[] in png_handle_iCCP() to fix OSS-fuzz issue.
+  Initialize png_ptr->row_buf[0] to 255 in png_read_row() to fix OSS-fuzz UMR.
+  Attempt to fix a UMR in png_set_text_2() to fix OSS-fuzz issue.
+  Increase minimum zlib stream from 9 to 14 in png_handle_iCCP(), to account
+    for the minimum 'deflate' stream, and relocate the test to a point
+    after the keyword has been read.
+  Check that the eXIf chunk has at least 2 bytes and begins with "II" or "MM".
+
+Version 1.6.32rc01 [August 18, 2017]
+  Added a set of "huge_xxxx_chunk.png" files to contrib/testpngs/crashers,
+    one for each known chunk type, with length = 2GB-1.
+  Check for 0 return from png_get_rowbytes() and added some (size_t) typecasts
+    in contrib/pngminus/*.c to stop some Coverity issues (162705, 162706,
+    and 162707).
+  Renamed chunks in contrib/testpngs/crashers to avoid having files whose
+    names differ only in case; this causes problems with some platforms
+    (github issue #172).
+
+Version 1.6.32rc02 [August 22, 2017]
+  Added contrib/oss-fuzz directory which contains files used by the oss-fuzz
+    project (https://github.com/google/oss-fuzz/tree/master/projects/libpng).
+
+Version 1.6.32 [August 24, 2017]
+  No changes.
+
+Version 1.6.33beta01 [August 28, 2017]
+  Added PNGMINUS_UNUSED macro to contrib/pngminus/p*.c and added missing
+    parenthesis in contrib/pngminus/pnm2png.c (bug report by Christian Hesse).
+  Fixed off-by-one error in png_do_check_palette_indexes() (Bug report
+    by Mick P., Source Forge Issue #269).
+
+Version 1.6.33beta02 [September 3, 2017]
+  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
+    to fix shortlived oss-fuzz issue 3234.
+  Compute a larger limit on IDAT because some applications write a deflate
+    buffer for each row (Bug report by Andrew Church).
+  Use current date (DATE) instead of release-date (RDATE) in last
+    changed date of contrib/oss-fuzz files.
+  Enabled ARM support in CMakeLists.txt (Bernd Kuhls).
+
+Version 1.6.33beta03 [September 14, 2017]
+  Fixed incorrect typecast of some arguments to png_malloc() and
+    png_calloc() that were png_uint_32 instead of png_alloc_size_t
+    (Bug report by "irwir" in Github libpng issue #175).
+  Use pnglibconf.h.prebuilt when building for ANDROID with cmake (Github
+    issue 162, by rcdailey).
+
+Version 1.6.33rc01 [September 20, 2017]
+  Initialize memory allocated by png_inflate to zero, using memset, to
+    stop an oss-fuzz "use of uninitialized value" detection in png_set_text_2()
+    due to truncated iTXt or zTXt chunk.
+  Initialize memory allocated by png_read_buffer to zero, using memset, to
+    stop an oss-fuzz "use of uninitialized value" detection in
+    png_icc_check_tag_table() due to truncated iCCP chunk.
+  Removed a redundant test (suggested by "irwir" in Github issue #180).
+
+Version 1.6.33rc02 [September 23, 2017]
+  Added an interlaced version of each file in contrib/pngsuite.
+  Relocate new memset() call in pngrutil.c.
+  Removed more redundant tests (suggested by "irwir" in Github issue #180).
+  Add support for loading images with associated alpha in the Simplified
+    API (Samuel Williams).
+
+Version 1.6.33 [September 28, 2017]
+  Revert contrib/oss-fuzz/libpng_read_fuzzer.cc to libpng-1.6.32 state.
+  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
+  Add end_info structure and png_read_end() to the libpng fuzzer.
+
+Version 1.6.34 [September 29, 2017]
+  Removed contrib/pngsuite/i*.png; some of them caused test failures.
+
+Version 1.6.35beta01 [March 6, 2018]
+  Restored 21 of the contrib/pngsuite/i*.png, which do not cause test
+    failures. Placed the remainder in contrib/pngsuite/interlaced/i*.png.
+  Added calls to png_set_*() transforms commonly used by browsers to
+    the fuzzer.
+  Removed some unnecessary brackets in pngrtran.c
+  Fixed miscellaneous typos (Patch by github user "luzpaz").
+  Change "ASM C" to "C ASM" in CMakeLists.txt
+  Fixed incorrect handling of bKGD chunk in sub-8-bit files (Cosmin)
+  Added hardware optimization directories to zip and 7z distributions.
+  Fixed incorrect bitmask for options.
+  Fixed many spelling typos.
+
+Version 1.6.35beta02 [March 28, 2018]
+  Make png_get_iCCP consistent with man page (allow compression-type argument
+  to be NULL, bug report by Lenard Szolnoki).
+
+Version 1.6.35 [July 15, 2018]
+  Replaced the remaining uses of png_size_t with size_t (Cosmin)
+  Fixed the calculation of row_factor in png_check_chunk_length
+    (reported by Thuan Pham in SourceForge issue #278)
+  Added missing parentheses to a macro definition
+    (suggested by "irwir" in GitHub issue #216)
+
+Version 1.6.36 [December 1, 2018]
+  Optimized png_do_expand_palette for ARM processors.
+  Improved performance by around 10-22% on a recent ARM Chromebook.
+    (Contributed by Richard Townsend, ARM Holdings)
+  Fixed manipulation of machine-specific optimization options.
+    (Contributed by Vicki Pfau)
+  Used memcpy instead of manual pointer arithmetic on Intel SSE2.
+    (Contributed by Samuel Williams)
+  Fixed build errors with MSVC on ARM64.
+    (Contributed by Zhijie Liang)
+  Fixed detection of libm in CMakeLists.
+    (Contributed by Cameron Cawley)
+  Fixed incorrect creation of pkg-config file in CMakeLists.
+    (Contributed by Kyle Bentley)
+  Fixed the CMake build on Windows MSYS by avoiding symlinks.
+  Fixed a build warning on OpenBSD.
+    (Contributed by Theo Buehler)
+  Fixed various typos in comments.
+    (Contributed by "luz.paz")
+  Raised the minimum required CMake version from 3.0.2 to 3.1.
+  Removed yet more of the vestigial support for pre-ANSI C compilers.
+  Removed ancient makefiles for ancient systems that have been broken
+    across all previous libpng-1.6.x versions.
+  Removed the Y2K compliance statement and the export control
+    information.
+  Applied various code style and documentation fixes.
+
+Version 1.6.37 [April 14, 2019]
+  Fixed a use-after-free vulnerability (CVE-2019-7317) in png_image_free.
+  Fixed a memory leak in the ARM NEON implementation of png_do_expand_palette.
+  Fixed a memory leak in pngtest.c.
+  Fixed two vulnerabilities (CVE-2018-14048, CVE-2018-14550) in
+    contrib/pngminus; refactor.
+  Changed the license of contrib/pngminus to MIT; refresh makefile and docs.
+    (Contributed by Willem van Schaik)
+  Fixed a typo in the libpng license v2.
+    (Contributed by Miguel Ojeda)
+  Added makefiles for AddressSanitizer-enabled builds.
+  Cleaned up various makefiles.
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net.
+Subscription is required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe.
diff --git a/extern/libpng/CMakeLists.txt b/extern/libpng/CMakeLists.txt
new file mode 100644
index 0000000000..6451fcf1bc
--- /dev/null
+++ b/extern/libpng/CMakeLists.txt
@@ -0,0 +1,931 @@
+# CMakeLists.txt
+
+# Copyright (C) 2018 Cosmin Truta
+# Copyright (C) 2007,2009-2018 Glenn Randers-Pehrson
+# Written by Christian Ehrlicher, 2007
+# Revised by Roger Lowman, 2009-2010
+# Revised by Clifford Yapp, 2011-2012,2017
+# Revised by Roger Leigh, 2016
+# Revised by Andreas Franek, 2016
+# Revised by Sam Serrels, 2017
+# Revised by Vadim Barkov, 2017
+# Revised by Vicky Pfau, 2018
+# Revised by Cameron Cawley, 2018
+# Revised by Cosmin Truta, 2018
+# Revised by Kyle Bentley, 2018
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+cmake_minimum_required(VERSION 3.1)
+cmake_policy(VERSION 3.1)
+
+project(libpng C ASM)
+enable_testing()
+
+set(PNGLIB_MAJOR 1)
+set(PNGLIB_MINOR 6)
+set(PNGLIB_RELEASE 37)
+set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
+set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})
+
+include(GNUInstallDirs)
+
+# needed packages
+
+# Allow users to specify location of Zlib.
+# Useful if zlib is being built alongside this as a sub-project.
+option(PNG_BUILD_ZLIB "Custom zlib Location, else find_package is used" OFF)
+
+if(NOT PNG_BUILD_ZLIB)
+  find_package(ZLIB REQUIRED)
+  include_directories(${ZLIB_INCLUDE_DIR})
+endif()
+
+if(UNIX AND NOT APPLE AND NOT BEOS AND NOT HAIKU)
+  find_library(M_LIBRARY m)
+else()
+  # libm is not needed and/or not available
+  set(M_LIBRARY "")
+endif()
+
+# COMMAND LINE OPTIONS
+option(PNG_SHARED "Build shared lib" ON)
+option(PNG_STATIC "Build static lib" ON)
+option(PNG_TESTS  "Build libpng tests" ON)
+
+# Many more configuration options could be added here
+option(PNG_FRAMEWORK "Build OS X framework" OFF)
+option(PNG_DEBUG "Build with debug output" OFF)
+option(PNG_HARDWARE_OPTIMIZATIONS "Enable hardware optimizations" ON)
+
+set(PNG_PREFIX "" CACHE STRING "Prefix to add to the API function names")
+set(DFA_XTRA "" CACHE FILEPATH "File containing extra configuration settings")
+
+if(PNG_HARDWARE_OPTIMIZATIONS)
+
+# set definitions and sources for arm
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" OR
+  CMAKE_SYSTEM_PROCESSOR MATCHES "^aarch64")
+  set(PNG_ARM_NEON_POSSIBLE_VALUES check on off)
+  set(PNG_ARM_NEON "check" CACHE STRING "Enable ARM NEON optimizations:
+     check: (default) use internal checking code;
+     off: disable the optimizations;
+     on: turn on unconditionally.")
+  set_property(CACHE PNG_ARM_NEON PROPERTY STRINGS
+     ${PNG_ARM_NEON_POSSIBLE_VALUES})
+  list(FIND PNG_ARM_NEON_POSSIBLE_VALUES ${PNG_ARM_NEON} index)
+  if(index EQUAL -1)
+    message(FATAL_ERROR
+            "PNG_ARM_NEON must be one of [${PNG_ARM_NEON_POSSIBLE_VALUES}]")
+  elseif(NOT ${PNG_ARM_NEON} STREQUAL "off")
+    set(libpng_arm_sources
+      arm/arm_init.c
+      arm/filter_neon.S
+      arm/filter_neon_intrinsics.c
+      arm/palette_neon_intrinsics.c)
+
+    if(${PNG_ARM_NEON} STREQUAL "on")
+      add_definitions(-DPNG_ARM_NEON_OPT=2)
+    elseif(${PNG_ARM_NEON} STREQUAL "check")
+      add_definitions(-DPNG_ARM_NEON_CHECK_SUPPORTED)
+    endif()
+  else()
+    add_definitions(-DPNG_ARM_NEON_OPT=0)
+  endif()
+endif()
+
+# set definitions and sources for powerpc
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "^powerpc*" OR
+   CMAKE_SYSTEM_PROCESSOR MATCHES "^ppc64*")
+  set(PNG_POWERPC_VSX_POSSIBLE_VALUES on off)
+  set(PNG_POWERPC_VSX "on" CACHE STRING "Enable POWERPC VSX optimizations:
+     off: disable the optimizations.")
+  set_property(CACHE PNG_POWERPC_VSX PROPERTY STRINGS
+     ${PNG_POWERPC_VSX_POSSIBLE_VALUES})
+  list(FIND PNG_POWERPC_VSX_POSSIBLE_VALUES ${PNG_POWERPC_VSX} index)
+  if(index EQUAL -1)
+    message(FATAL_ERROR
+            "PNG_POWERPC_VSX must be one of [${PNG_POWERPC_VSX_POSSIBLE_VALUES}]")
+  elseif(NOT ${PNG_POWERPC_VSX} STREQUAL "off")
+    set(libpng_powerpc_sources
+      powerpc/powerpc_init.c
+      powerpc/filter_vsx_intrinsics.c)
+    if(${PNG_POWERPC_VSX} STREQUAL "on")
+      add_definitions(-DPNG_POWERPC_VSX_OPT=2)
+    endif()
+  else()
+    add_definitions(-DPNG_POWERPC_VSX_OPT=0)
+  endif()
+endif()
+
+# set definitions and sources for intel
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "^i?86" OR
+   CMAKE_SYSTEM_PROCESSOR MATCHES "^x86_64*")
+  set(PNG_INTEL_SSE_POSSIBLE_VALUES on off)
+  set(PNG_INTEL_SSE "on" CACHE STRING "Enable INTEL_SSE optimizations:
+     off: disable the optimizations")
+  set_property(CACHE PNG_INTEL_SSE PROPERTY STRINGS
+     ${PNG_INTEL_SSE_POSSIBLE_VALUES})
+  list(FIND PNG_INTEL_SSE_POSSIBLE_VALUES ${PNG_INTEL_SSE} index)
+  if(index EQUAL -1)
+    message(FATAL_ERROR
+            "PNG_INTEL_SSE must be one of [${PNG_INTEL_SSE_POSSIBLE_VALUES}]")
+  elseif(NOT ${PNG_INTEL_SSE} STREQUAL "off")
+    set(libpng_intel_sources
+      intel/intel_init.c
+      intel/filter_sse2_intrinsics.c)
+    if(${PNG_INTEL_SSE} STREQUAL "on")
+      add_definitions(-DPNG_INTEL_SSE_OPT=1)
+    endif()
+  else()
+    add_definitions(-DPNG_INTEL_SSE_OPT=0)
+  endif()
+endif()
+
+# set definitions and sources for MIPS
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "mipsel*" OR
+   CMAKE_SYSTEM_PROCESSOR MATCHES "mips64el*")
+  set(PNG_MIPS_MSA_POSSIBLE_VALUES on off)
+  set(PNG_MIPS_MSA "on" CACHE STRING "Enable MIPS_MSA optimizations:
+     off: disable the optimizations")
+  set_property(CACHE PNG_MIPS_MSA PROPERTY STRINGS
+     ${PNG_MIPS_MSA_POSSIBLE_VALUES})
+  list(FIND PNG_MIPS_MSA_POSSIBLE_VALUES ${PNG_MIPS_MSA} index)
+  if(index EQUAL -1)
+    message(FATAL_ERROR
+            "PNG_MIPS_MSA must be one of [${PNG_MIPS_MSA_POSSIBLE_VALUES}]")
+  elseif(NOT ${PNG_MIPS_MSA} STREQUAL "off")
+    set(libpng_mips_sources
+      mips/mips_init.c
+      mips/filter_msa_intrinsics.c)
+    if(${PNG_MIPS_MSA} STREQUAL "on")
+      add_definitions(-DPNG_MIPS_MSA_OPT=2)
+    endif()
+  else()
+    add_definitions(-DPNG_MIPS_MSA_OPT=0)
+  endif()
+endif()
+
+else(PNG_HARDWARE_OPTIMIZATIONS)
+
+# set definitions and sources for arm
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" OR
+   CMAKE_SYSTEM_PROCESSOR MATCHES "^aarch64")
+  add_definitions(-DPNG_ARM_NEON_OPT=0)
+endif()
+
+# set definitions and sources for powerpc
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "^powerpc*" OR
+   CMAKE_SYSTEM_PROCESSOR MATCHES "^ppc64*")
+  add_definitions(-DPNG_POWERPC_VSX_OPT=0)
+endif()
+
+# set definitions and sources for intel
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "^i?86" OR
+   CMAKE_SYSTEM_PROCESSOR MATCHES "^x86_64*")
+  add_definitions(-DPNG_INTEL_SSE_OPT=0)
+endif()
+
+# set definitions and sources for MIPS
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "mipsel*" OR
+   CMAKE_SYSTEM_PROCESSOR MATCHES "mips64el*")
+  add_definitions(-DPNG_MIPS_MSA_OPT=0)
+endif()
+
+endif(PNG_HARDWARE_OPTIMIZATIONS)
+
+# SET LIBNAME
+set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR})
+
+# to distinguish between debug and release lib
+set(CMAKE_DEBUG_POSTFIX "d")
+
+include(CheckCSourceCompiles)
+option(ld-version-script "Enable linker version script" ON)
+if(ld-version-script AND NOT APPLE)
+  # Check if LD supports linker scripts.
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/conftest.map" "VERS_1 {
+        global: sym;
+        local: *;
+};
+
+VERS_2 {
+        global: sym2;
+                main;
+} VERS_1;
+")
+  set(CMAKE_REQUIRED_FLAGS_SAVE ${CMAKE_REQUIRED_FLAGS})
+  set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS} "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/conftest.map'")
+  check_c_source_compiles("void sym(void) {}
+void sym2(void) {}
+int main(void) {return 0;}
+" HAVE_LD_VERSION_SCRIPT)
+  if(NOT HAVE_LD_VERSION_SCRIPT)
+    set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS_SAVE} "-Wl,-M -Wl,${CMAKE_CURRENT_BINARY_DIR}/conftest.map")
+  check_c_source_compiles("void sym(void) {}
+void sym2(void) {}
+int main(void) {return 0;}
+" HAVE_SOLARIS_LD_VERSION_SCRIPT)
+  endif()
+  set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS_SAVE})
+  file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/conftest.map")
+endif()
+
+# Find symbol prefix.  Likely obsolete and unnecessary with recent
+# toolchains (it's not done in many other projects).
+function(symbol_prefix)
+  set(SYMBOL_PREFIX)
+
+  execute_process(COMMAND "${CMAKE_C_COMPILER}" "-E" "-"
+                  INPUT_FILE /dev/null
+                  OUTPUT_VARIABLE OUT
+                  RESULT_VARIABLE STATUS)
+
+  if(CPP_FAIL)
+    message(WARNING "Failed to run the C preprocessor")
+  endif()
+
+  string(REPLACE "\n" ";" OUT "${OUT}")
+  foreach(line ${OUT})
+    string(REGEX MATCH "^PREFIX=" found_match "${line}")
+    if(found_match)
+      string(REGEX REPLACE "^PREFIX=(.*\)" "\\1" prefix "${line}")
+      string(REGEX MATCH "__USER_LABEL_PREFIX__" found_match "${prefix}")
+      if(found_match)
+        string(REGEX REPLACE "(.*)__USER_LABEL_PREFIX__(.*)" "\\1\\2" prefix "${prefix}")
+      endif()
+      set(SYMBOL_PREFIX "${prefix}")
+    endif()
+  endforeach()
+
+  message(STATUS "Symbol prefix: ${SYMBOL_PREFIX}")
+  set(SYMBOL_PREFIX "${SYMBOL_PREFIX}" PARENT_SCOPE)
+endfunction()
+
+if(UNIX)
+  symbol_prefix()
+endif()
+
+find_program(AWK NAMES gawk awk)
+
+include_directories(${CMAKE_CURRENT_BINARY_DIR})
+
+if(NOT AWK OR ANDROID)
+  # No awk available to generate sources; use pre-built pnglibconf.h
+  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt
+                 ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h)
+  add_custom_target(genfiles) # Dummy
+else()
+  include(CMakeParseArguments)
+  # Generate .chk from .out with awk
+  # generate_chk(INPUT inputfile OUTPUT outputfile [DEPENDS dep1 [dep2...]])
+  function(generate_chk)
+    set(options)
+    set(oneValueArgs INPUT OUTPUT)
+    set(multiValueArgs DEPENDS)
+    cmake_parse_arguments(_GC "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+    if(NOT _GC_INPUT)
+      message(FATAL_ERROR "generate_chk: Missing INPUT argument")
+    endif()
+    if(NOT _GC_OUTPUT)
+      message(FATAL_ERROR "generate_chk: Missing OUTPUT argument")
+    endif()
+
+    add_custom_command(OUTPUT "${_GC_OUTPUT}"
+                       COMMAND "${CMAKE_COMMAND}"
+                               "-DINPUT=${_GC_INPUT}"
+                               "-DOUTPUT=${_GC_OUTPUT}"
+                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/genchk.cmake"
+                       DEPENDS "${_GC_INPUT}" ${_GC_DEPENDS}
+                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+  endfunction()
+
+  # Generate .out from .c with awk
+  # generate_out(INPUT inputfile OUTPUT outputfile [DEPENDS dep1 [dep2...]])
+  function(generate_out)
+    set(options)
+    set(oneValueArgs INPUT OUTPUT)
+    set(multiValueArgs DEPENDS)
+    cmake_parse_arguments(_GO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+    if(NOT _GO_INPUT)
+      message(FATAL_ERROR "generate_out: Missing INPUT argument")
+    endif()
+    if(NOT _GO_OUTPUT)
+      message(FATAL_ERROR "generate_out: Missing OUTPUT argument")
+    endif()
+
+    add_custom_command(OUTPUT "${_GO_OUTPUT}"
+                       COMMAND "${CMAKE_COMMAND}"
+                               "-DINPUT=${_GO_INPUT}"
+                               "-DOUTPUT=${_GO_OUTPUT}"
+                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/genout.cmake"
+                       DEPENDS "${_GO_INPUT}" ${_GO_DEPENDS}
+                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+  endfunction()
+
+  # Generate specific source file with awk
+  # generate_source(OUTPUT outputfile [DEPENDS dep1 [dep2...]])
+  function(generate_source)
+    set(options)
+    set(oneValueArgs OUTPUT)
+    set(multiValueArgs DEPENDS)
+    cmake_parse_arguments(_GSO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+    if(NOT _GSO_OUTPUT)
+      message(FATAL_ERROR "generate_source: Missing OUTPUT argument")
+    endif()
+
+    add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${_GSO_OUTPUT}"
+                       COMMAND "${CMAKE_COMMAND}"
+                               "-DOUTPUT=${_GSO_OUTPUT}"
+                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/gensrc.cmake"
+                       DEPENDS ${_GSO_DEPENDS}
+                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+  endfunction()
+
+  # Copy file
+  function(generate_copy source destination)
+    add_custom_command(OUTPUT "${destination}"
+                       COMMAND "${CMAKE_COMMAND}" -E remove "${destination}"
+                       COMMAND "${CMAKE_COMMAND}" -E copy "${source}"
+                                                          "${destination}"
+                       DEPENDS "${source}")
+  endfunction()
+
+  # Generate scripts/pnglibconf.h
+  generate_source(OUTPUT "scripts/pnglibconf.c"
+                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
+                          "${CMAKE_CURRENT_SOURCE_DIR}/scripts/options.awk"
+                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")
+
+  # Generate pnglibconf.c
+  generate_source(OUTPUT "pnglibconf.c"
+                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
+                          "${CMAKE_CURRENT_SOURCE_DIR}/scripts/options.awk"
+                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")
+
+  if(PNG_PREFIX)
+    set(PNGLIBCONF_H_EXTRA_DEPENDS
+        "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
+        "${CMAKE_CURRENT_SOURCE_DIR}/scripts/macro.lst")
+    set(PNGPREFIX_H_EXTRA_DEPENDS
+        "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out")
+  endif()
+
+  generate_out(INPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out")
+
+  # Generate pnglibconf.h
+  generate_source(OUTPUT "pnglibconf.h"
+                  DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
+                          ${PNGLIBCONF_H_EXTRA_DEPENDS})
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/intprefix.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out"
+               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/prefix.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
+               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
+                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out")
+
+  # Generate pngprefix.h
+  generate_source(OUTPUT "pngprefix.h"
+                  DEPENDS ${PNGPREFIX_H_EXTRA_DEPENDS})
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/sym.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
+               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
+               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt")
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/vers.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
+               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
+                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")
+
+  generate_chk(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
+               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/checksym.awk"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.def")
+
+  add_custom_target(symbol-check DEPENDS
+                    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk")
+
+  generate_copy("${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
+                "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym")
+  generate_copy("${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
+                "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers")
+
+  add_custom_target(genvers DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers")
+  add_custom_target(gensym DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym")
+
+  add_custom_target("genprebuilt"
+                    COMMAND "${CMAKE_COMMAND}"
+                            "-DOUTPUT=scripts/pnglibconf.h.prebuilt"
+                            -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/gensrc.cmake"
+                    WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+
+  # A single target handles generation of all generated files.  If
+  # they are depended upon separately by multiple targets, this
+  # confuses parallel make (it would require a separate top-level
+  # target for each file to track the dependencies properly).
+  add_custom_target(genfiles DEPENDS
+    "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym"
+    "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers"
+    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
+    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
+    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
+    "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h"
+    "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out"
+    "${CMAKE_CURRENT_BINARY_DIR}/scripts/pnglibconf.c"
+    "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
+    "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
+    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
+    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
+    "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out")
+endif(NOT AWK OR ANDROID)
+
+# OUR SOURCES
+set(libpng_public_hdrs
+  png.h
+  pngconf.h
+  "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
+)
+set(libpng_private_hdrs
+  pngpriv.h
+  pngdebug.h
+  pnginfo.h
+  pngstruct.h
+)
+if(AWK AND NOT ANDROID)
+  list(APPEND libpng_private_hdrs "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h")
+endif()
+set(libpng_sources
+  ${libpng_public_hdrs}
+  ${libpng_private_hdrs}
+  png.c
+  pngerror.c
+  pngget.c
+  pngmem.c
+  pngpread.c
+  pngread.c
+  pngrio.c
+  pngrtran.c
+  pngrutil.c
+  pngset.c
+  pngtrans.c
+  pngwio.c
+  pngwrite.c
+  pngwtran.c
+  pngwutil.c
+  ${libpng_arm_sources}
+  ${libpng_intel_sources}
+  ${libpng_mips_sources}
+  ${libpng_powerpc_sources}
+)
+set(pngtest_sources
+  pngtest.c
+)
+set(pngvalid_sources
+  contrib/libtests/pngvalid.c
+)
+set(pngstest_sources
+  contrib/libtests/pngstest.c
+)
+set(pngunknown_sources
+  contrib/libtests/pngunknown.c
+)
+set(pngimage_sources
+  contrib/libtests/pngimage.c
+)
+set(pngfix_sources
+  contrib/tools/pngfix.c
+)
+set(png_fix_itxt_sources
+  contrib/tools/png-fix-itxt.c
+)
+
+if(MSVC)
+  add_definitions(-D_CRT_SECURE_NO_DEPRECATE)
+endif()
+
+if(PNG_DEBUG)
+  add_definitions(-DPNG_DEBUG)
+endif()
+
+# NOW BUILD OUR TARGET
+include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${ZLIB_INCLUDE_DIR})
+
+unset(PNG_LIB_TARGETS)
+
+if(PNG_SHARED)
+  add_library(png SHARED ${libpng_sources})
+  set(PNG_LIB_TARGETS png)
+  set_target_properties(png PROPERTIES OUTPUT_NAME ${PNG_LIB_NAME})
+  add_dependencies(png genfiles)
+  if(MSVC)
+    # msvc does not append 'lib' - do it here to have consistent name
+    set_target_properties(png PROPERTIES PREFIX "lib")
+    set_target_properties(png PROPERTIES IMPORT_PREFIX "lib")
+  endif()
+  target_link_libraries(png ${ZLIB_LIBRARY} ${M_LIBRARY})
+
+  if(UNIX AND AWK)
+    if(HAVE_LD_VERSION_SCRIPT)
+      set_target_properties(png PROPERTIES LINK_FLAGS
+        "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
+    elseif(HAVE_SOLARIS_LD_VERSION_SCRIPT)
+      set_target_properties(png PROPERTIES LINK_FLAGS
+        "-Wl,-M -Wl,'${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
+    endif()
+  endif()
+endif()
+
+if(PNG_STATIC)
+  # does not work without changing name
+  set(PNG_LIB_NAME_STATIC png_static)
+  add_library(png_static STATIC ${libpng_sources})
+  add_dependencies(png_static genfiles)
+  # MSVC doesn't use a different file extension for shared vs. static
+  # libs.  We are able to change OUTPUT_NAME to remove the _static
+  # for all other platforms.
+  if(NOT MSVC)
+    set_target_properties(png_static PROPERTIES
+      OUTPUT_NAME "${PNG_LIB_NAME}"
+      CLEAN_DIRECT_OUTPUT 1)
+  else()
+    set_target_properties(png_static PROPERTIES
+      OUTPUT_NAME "${PNG_LIB_NAME}_static"
+      CLEAN_DIRECT_OUTPUT 1)
+  endif()
+  list(APPEND PNG_LIB_TARGETS png_static)
+  if(MSVC)
+    # msvc does not append 'lib' - do it here to have consistent name
+    set_target_properties(png_static PROPERTIES PREFIX "lib")
+  endif()
+  target_link_libraries(png_static ${ZLIB_LIBRARY} ${M_LIBRARY})
+endif()
+
+if(PNG_FRAMEWORK)
+  set(PNG_LIB_NAME_FRAMEWORK png_framework)
+  add_library(png_framework SHARED ${libpng_sources})
+  add_dependencies(png_framework genfiles)
+  list(APPEND PNG_LIB_TARGETS png_framework)
+  set_target_properties(png_framework PROPERTIES
+    FRAMEWORK TRUE
+    FRAMEWORK_VERSION ${PNGLIB_VERSION}
+    MACOSX_FRAMEWORK_SHORT_VERSION_STRING ${PNGLIB_MAJOR}.${PNGLIB_MINOR}
+    MACOSX_FRAMEWORK_BUNDLE_VERSION ${PNGLIB_VERSION}
+    MACOSX_FRAMEWORK_IDENTIFIER org.libpng.libpng
+    XCODE_ATTRIBUTE_INSTALL_PATH "@rpath"
+    PUBLIC_HEADER "${libpng_public_hdrs}"
+    OUTPUT_NAME png)
+  target_link_libraries(png_framework ${ZLIB_LIBRARY} ${M_LIBRARY})
+endif()
+
+if(NOT PNG_LIB_TARGETS)
+  message(SEND_ERROR
+    "No library variant selected to build. "
+    "Please enable at least one of the following options: "
+    "PNG_STATIC, PNG_SHARED, PNG_FRAMEWORK")
+endif()
+
+if(PNG_SHARED AND WIN32)
+  set_target_properties(png PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
+endif()
+
+function(png_add_test)
+  set(options)
+  set(oneValueArgs NAME COMMAND)
+  set(multiValueArgs OPTIONS FILES)
+  cmake_parse_arguments(_PAT "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+
+  if(NOT _PAT_NAME)
+    message(FATAL_ERROR "png_add_test: Missing NAME argument")
+  endif()
+  if(NOT _PAT_COMMAND)
+    message(FATAL_ERROR "png_add_test: Missing COMMAND argument")
+  endif()
+
+  set(TEST_OPTIONS "${_PAT_OPTIONS}")
+  set(TEST_FILES "${_PAT_FILES}")
+
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/test.cmake.in"
+                 "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake" @ONLY)
+  add_test(NAME "${_PAT_NAME}"
+           COMMAND "${CMAKE_COMMAND}"
+           "-DLIBPNG=$<TARGET_FILE:png>"
+           "-DTEST_COMMAND=$<TARGET_FILE:${_PAT_COMMAND}>"
+           -P "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake")
+endfunction()
+
+if(PNG_TESTS AND PNG_SHARED)
+  # Find test PNG files by globbing, but sort lists to ensure
+  # consistency between different filesystems.
+  file(GLOB PNGSUITE_PNGS "${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/*.png")
+  list(SORT PNGSUITE_PNGS)
+  file(GLOB TEST_PNGS "${CMAKE_CURRENT_SOURCE_DIR}/contrib/testpngs/*.png")
+  list(SORT TEST_PNGS)
+
+  set(PNGTEST_PNG "${CMAKE_CURRENT_SOURCE_DIR}/pngtest.png")
+
+  add_executable(pngtest ${pngtest_sources})
+  target_link_libraries(pngtest png)
+
+  png_add_test(NAME pngtest COMMAND pngtest FILES "${PNGTEST_PNG}")
+
+  add_executable(pngvalid ${pngvalid_sources})
+  target_link_libraries(pngvalid png)
+
+  png_add_test(NAME pngvalid-gamma-16-to-8
+               COMMAND pngvalid OPTIONS --gamma-16-to-8)
+  png_add_test(NAME pngvalid-gamma-alpha-mode
+               COMMAND pngvalid OPTIONS --gamma-alpha-mode)
+  png_add_test(NAME pngvalid-gamma-background
+               COMMAND pngvalid OPTIONS --gamma-background)
+  png_add_test(NAME pngvalid-gamma-expand16-alpha-mode
+               COMMAND pngvalid OPTIONS --gamma-alpha-mode --expand16)
+  png_add_test(NAME pngvalid-gamma-expand16-background
+               COMMAND pngvalid OPTIONS --gamma-background --expand16)
+  png_add_test(NAME pngvalid-gamma-expand16-transform
+               COMMAND pngvalid OPTIONS --gamma-transform --expand16)
+  png_add_test(NAME pngvalid-gamma-sbit
+               COMMAND pngvalid OPTIONS --gamma-sbit)
+  png_add_test(NAME pngvalid-gamma-threshold
+               COMMAND pngvalid OPTIONS --gamma-threshold)
+  png_add_test(NAME pngvalid-gamma-transform
+               COMMAND pngvalid OPTIONS --gamma-transform)
+  png_add_test(NAME pngvalid-progressive-interlace-standard
+               COMMAND pngvalid OPTIONS --standard --progressive-read --interlace)
+  png_add_test(NAME pngvalid-progressive-size
+               COMMAND pngvalid OPTIONS --size --progressive-read)
+  png_add_test(NAME pngvalid-progressive-standard
+               COMMAND pngvalid OPTIONS --standard --progressive-read)
+  png_add_test(NAME pngvalid-standard
+               COMMAND pngvalid OPTIONS --standard)
+  png_add_test(NAME pngvalid-transform
+               COMMAND pngvalid OPTIONS --transform)
+
+  add_executable(pngstest ${pngstest_sources})
+  target_link_libraries(pngstest png)
+
+  foreach(gamma_type 1.8 linear none sRGB)
+    foreach(alpha_type none alpha)
+      set(PNGSTEST_FILES)
+      foreach(test_png ${TEST_PNGS})
+        string(REGEX MATCH ".*-linear[-.].*" TEST_PNG_LINEAR "${test_png}")
+        string(REGEX MATCH ".*-sRGB[-.].*" TEST_PNG_SRGB "${test_png}")
+        string(REGEX MATCH ".*-1.8[-.].*" TEST_PNG_G18 "${test_png}")
+        string(REGEX MATCH ".*-alpha-.*" TEST_PNG_ALPHA "${test_png}")
+
+        set(TEST_PNG_VALID TRUE)
+
+        if(TEST_PNG_ALPHA)
+          if(NOT "${alpha_type}" STREQUAL "alpha")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        else()
+          if("${alpha_type}" STREQUAL "alpha")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        endif()
+
+        if(TEST_PNG_LINEAR)
+          if(NOT "${gamma_type}" STREQUAL "linear")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        elseif(TEST_PNG_SRGB)
+          if(NOT "${gamma_type}" STREQUAL "sRGB")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        elseif(TEST_PNG_G18)
+          if(NOT "${gamma_type}" STREQUAL "1.8")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        else()
+          if(NOT "${gamma_type}" STREQUAL "none")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        endif()
+
+        if(TEST_PNG_VALID)
+          list(APPEND PNGSTEST_FILES "${test_png}")
+        endif()
+      endforeach()
+      # Should already be sorted, but sort anyway to be certain.
+      list(SORT PNGSTEST_FILES)
+      png_add_test(NAME pngstest-${gamma_type}-${alpha_type}
+                   COMMAND pngstest
+                   OPTIONS --tmpfile "${gamma_type}-${alpha_type}-" --log
+                   FILES ${PNGSTEST_FILES})
+    endforeach()
+  endforeach()
+
+  add_executable(pngunknown ${pngunknown_sources})
+  target_link_libraries(pngunknown png)
+
+  png_add_test(NAME pngunknown-discard COMMAND pngunknown OPTIONS --strict default=discard FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-IDAT COMMAND pngunknown OPTIONS --strict default=discard IDAT=save FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-if-safe COMMAND pngunknown OPTIONS --strict default=if-safe FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-sAPI COMMAND pngunknown OPTIONS --strict bKGD=save cHRM=save gAMA=save all=discard iCCP=save sBIT=save sRGB=save FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-save COMMAND pngunknown OPTIONS --strict default=save FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-sTER COMMAND pngunknown OPTIONS --strict sTER=if-safe FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-vpAg COMMAND pngunknown OPTIONS --strict vpAg=if-safe FILES "${PNGTEST_PNG}")
+
+  add_executable(pngimage ${pngimage_sources})
+  target_link_libraries(pngimage png)
+
+  png_add_test(NAME pngimage-quick COMMAND pngimage OPTIONS --list-combos --log FILES ${PNGSUITE_PNGS})
+  png_add_test(NAME pngimage-full COMMAND pngimage OPTIONS --exhaustive --list-combos --log FILES ${PNGSUITE_PNGS})
+endif()
+
+if(PNG_SHARED)
+  add_executable(pngfix ${pngfix_sources})
+  target_link_libraries(pngfix png)
+  set(PNG_BIN_TARGETS pngfix)
+
+  add_executable(png-fix-itxt ${png_fix_itxt_sources})
+  target_link_libraries(png-fix-itxt ${ZLIB_LIBRARY} ${M_LIBRARY})
+  list(APPEND PNG_BIN_TARGETS png-fix-itxt)
+endif()
+
+# Set a variable with CMake code which:
+# Creates a symlink from src to dest (if possible) or alternatively
+# copies if different.
+include(CMakeParseArguments)
+
+function(create_symlink DEST_FILE)
+
+  cmake_parse_arguments(S "" "FILE;TARGET" "" ${ARGN})
+
+  if(NOT S_TARGET AND NOT S_FILE)
+    message(FATAL_ERROR "create_symlink: Missing TARGET or FILE argument")
+  endif()
+
+  if(S_TARGET AND S_FILE)
+    message(FATAL_ERROR "create_symlink: Both source file ${S_FILE} and build target ${S_TARGET} arguments are present; can only have one.")
+  endif()
+
+  if(S_FILE)
+    # If we don't need to symlink something that's coming from a build target,
+    # we can go ahead and symlink/copy at configure time.
+    if(CMAKE_HOST_WIN32 AND NOT CYGWIN)
+      execute_process(
+        COMMAND "${CMAKE_COMMAND}" -E copy_if_different ${S_FILE} ${DEST_FILE}
+        WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+    else()
+      execute_process(
+        COMMAND ${CMAKE_COMMAND} -E create_symlink ${S_FILE} ${DEST_FILE}
+        WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+    endif()
+  endif()
+
+  if(S_TARGET)
+    # We need to use generator expressions, which can be a bit tricky, so for
+    # simplicity make the symlink a POST_BUILD step and use the TARGET
+    # signature of add_custom_command.
+    if(CMAKE_HOST_WIN32 AND NOT CYGWIN)
+      add_custom_command(TARGET ${S_TARGET} POST_BUILD
+        COMMAND "${CMAKE_COMMAND}" -E copy_if_different $<TARGET_LINKER_FILE_NAME:${S_TARGET}> $<TARGET_LINKER_FILE_DIR:${S_TARGET}>/${DEST_FILE})
+    else()
+      add_custom_command(TARGET ${S_TARGET} POST_BUILD
+        COMMAND "${CMAKE_COMMAND}" -E create_symlink $<TARGET_LINKER_FILE_NAME:${S_TARGET}> $<TARGET_LINKER_FILE_DIR:${S_TARGET}>/${DEST_FILE})
+    endif()
+  endif()
+
+endfunction()
+
+# Create source generation scripts.
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/genchk.cmake.in
+               ${CMAKE_CURRENT_BINARY_DIR}/scripts/genchk.cmake @ONLY)
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/genout.cmake.in
+               ${CMAKE_CURRENT_BINARY_DIR}/scripts/genout.cmake @ONLY)
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/gensrc.cmake.in
+               ${CMAKE_CURRENT_BINARY_DIR}/scripts/gensrc.cmake @ONLY)
+
+# libpng is a library so default to 'lib'
+if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
+  set(CMAKE_INSTALL_LIBDIR lib)
+endif()
+
+# CREATE PKGCONFIG FILES
+# We use the same files like ./configure, so we have to set its vars.
+# Only do this on Windows for Cygwin - the files don't make much sense outside
+# of a UNIX look-alike.
+if(NOT WIN32 OR CYGWIN OR MINGW)
+  set(prefix      ${CMAKE_INSTALL_PREFIX})
+  set(exec_prefix ${CMAKE_INSTALL_PREFIX})
+  set(libdir      ${CMAKE_INSTALL_FULL_LIBDIR})
+  set(includedir  ${CMAKE_INSTALL_FULL_INCLUDEDIR})
+  set(LIBS        "-lz -lm")
+  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in
+    ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc @ONLY)
+  create_symlink(libpng.pc FILE ${PNGLIB_NAME}.pc)
+
+  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in
+    ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config @ONLY)
+  create_symlink(libpng-config FILE ${PNGLIB_NAME}-config)
+endif()
+
+# SET UP LINKS
+if(PNG_SHARED)
+  set_target_properties(png PROPERTIES
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.37
+    VERSION 16.${PNGLIB_RELEASE}.0
+    SOVERSION 16
+    CLEAN_DIRECT_OUTPUT 1)
+endif()
+
+# INSTALL
+if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL)
+  install(TARGETS ${PNG_LIB_TARGETS}
+          EXPORT libpng
+          RUNTIME DESTINATION bin
+          LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+          ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+          FRAMEWORK DESTINATION ${CMAKE_INSTALL_LIBDIR})
+
+  if(PNG_SHARED)
+    # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin
+    if(CYGWIN OR MINGW)
+      create_symlink(libpng${CMAKE_IMPORT_LIBRARY_SUFFIX} TARGET png)
+      install(FILES $<TARGET_LINKER_FILE_DIR:png>/libpng${CMAKE_IMPORT_LIBRARY_SUFFIX}
+              DESTINATION ${CMAKE_INSTALL_LIBDIR})
+    endif()
+
+    if(NOT WIN32)
+      create_symlink(libpng${CMAKE_SHARED_LIBRARY_SUFFIX} TARGET png)
+      install(FILES $<TARGET_LINKER_FILE_DIR:png>/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
+              DESTINATION ${CMAKE_INSTALL_LIBDIR})
+    endif()
+  endif()
+
+  if(PNG_STATIC)
+    if(NOT WIN32 OR CYGWIN OR MINGW)
+      create_symlink(libpng${CMAKE_STATIC_LIBRARY_SUFFIX} TARGET png_static)
+      install(FILES $<TARGET_LINKER_FILE_DIR:png_static>/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
+              DESTINATION ${CMAKE_INSTALL_LIBDIR})
+    endif()
+  endif()
+endif()
+
+if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL)
+  install(FILES ${libpng_public_hdrs} DESTINATION include)
+  install(FILES ${libpng_public_hdrs} DESTINATION include/${PNGLIB_NAME})
+endif()
+if(NOT SKIP_INSTALL_EXECUTABLES AND NOT SKIP_INSTALL_ALL)
+  if(NOT WIN32 OR CYGWIN OR MINGW)
+    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config DESTINATION bin)
+    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config DESTINATION bin)
+  endif()
+endif()
+
+if(NOT SKIP_INSTALL_PROGRAMS AND NOT SKIP_INSTALL_ALL)
+  install(TARGETS ${PNG_BIN_TARGETS}
+          RUNTIME DESTINATION bin)
+endif()
+
+if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL)
+  # Install man pages
+  if(NOT PNG_MAN_DIR)
+    set(PNG_MAN_DIR "share/man")
+  endif()
+  install(FILES libpng.3 libpngpf.3 DESTINATION ${PNG_MAN_DIR}/man3)
+  install(FILES png.5 DESTINATION ${PNG_MAN_DIR}/man5)
+  # Install pkg-config files
+  if(NOT CMAKE_HOST_WIN32 OR CYGWIN OR MINGW)
+    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc
+            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config
+            DESTINATION bin)
+    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc
+            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
+            DESTINATION bin)
+  endif()
+endif()
+
+# Create an export file that CMake users can include() to import our targets.
+if(NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL)
+  install(EXPORT libpng DESTINATION lib/libpng FILE lib${PNG_LIB_NAME}.cmake)
+endif()
+
+# what's with libpng-manual.txt and all the extra files?
+
+# UNINSTALL
+# do we need this?
+
+# DIST
+# do we need this?
+
+# to create msvc import lib for mingw compiled shared lib
+# pexports libpng.dll > libpng.def
+# lib /def:libpng.def /machine:x86
diff --git a/extern/libpng/INSTALL b/extern/libpng/INSTALL
new file mode 100644
index 0000000000..4c17022515
--- /dev/null
+++ b/extern/libpng/INSTALL
@@ -0,0 +1,465 @@
+
+    Installing libpng
+
+Contents
+
+       I. Simple installation
+      II. Rebuilding the configure scripts
+     III. Using scripts/makefile*
+      IV. Using cmake
+       V. Directory structure
+      VI. Building with project files
+     VII. Building with makefiles
+    VIII. Configuring libpng for 16-bit platforms
+      IX. Configuring for DOS
+       X. Configuring for Medium Model
+      XI. Prepending a prefix to exported symbols
+     XII. Configuring for compiler xxx:
+    XIII. Removing unwanted object code
+     XIV. Enabling or disabling hardware optimizations
+      XV. Changes to the build and configuration of libpng in libpng-1.5.x
+     XVI. Setjmp/longjmp issues
+    XVII. Common linking failures
+   XVIII. Other sources of information about libpng
+
+I. Simple installation
+
+On Unix/Linux and similar systems, you can simply type
+
+    ./configure [--prefix=/path]
+    make check
+    make install
+
+and ignore the rest of this document.  "/path" is the path to the directory
+where you want to install the libpng "lib", "include", and "bin"
+subdirectories.
+
+If you downloaded a GIT clone, you will need to run ./autogen.sh before
+running ./configure, to create "configure" and "Makefile.in" which are
+not included in the GIT repository.
+
+Note that "configure" is only included in the "*.tar" distributions and not
+in the "*.zip" or "*.7z" distributions. If you downloaded one of those
+distributions, see "Building with project files" or "Building with makefiles",
+below.
+
+II. Rebuilding the configure scripts
+
+If configure does not work on your system, or if you have a need to
+change configure.ac or Makefile.am, and you have a reasonably
+up-to-date set of tools, running ./autogen.sh in a git clone before
+running ./configure may fix the problem.  To be really sure that you
+aren't using any of the included pre-built scripts, especially if you
+are building from a tar distribution instead of a git distribution,
+do this:
+
+    ./configure --enable-maintainer-mode
+    make maintainer-clean
+    ./autogen.sh --maintainer --clean
+    ./autogen.sh --maintainer
+    ./configure [--prefix=/path] [other options]
+    make
+    make install
+    make check
+
+III. Using scripts/makefile*
+
+Instead, you can use one of the custom-built makefiles in the
+"scripts" directory
+
+    cp scripts/pnglibconf.h.prebuilt pnglibconf.h
+    cp scripts/makefile.system makefile
+    make test
+    make install
+
+The files that are presently available in the scripts directory
+are listed and described in scripts/README.txt.
+
+Or you can use one of the "projects" in the "projects" directory.
+
+Before installing libpng, you must first install zlib, if it
+is not already on your system.  zlib can usually be found
+wherever you got libpng; otherwise go to https://zlib.net/.  You can
+place zlib in the same directory as libpng or in another directory.
+
+If your system already has a preinstalled zlib you will still need
+to have access to the zlib.h and zconf.h include files that
+correspond to the version of zlib that's installed.
+
+If you wish to test with a particular zlib that is not first in the
+standard library search path, put ZLIBLIB, ZLIBINC, CPPFLAGS, LDFLAGS,
+and LD_LIBRARY_PATH in your environment before running "make test"
+or "make distcheck":
+
+    ZLIBLIB=/path/to/lib export ZLIBLIB
+    ZLIBINC=/path/to/include export ZLIBINC
+    CPPFLAGS="-I$ZLIBINC" export CPPFLAGS
+    LDFLAGS="-L$ZLIBLIB" export LDFLAGS
+    LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
+
+If you are using one of the makefile scripts, put ZLIBLIB and ZLIBINC
+in your environment and type
+
+    make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test
+
+IV. Using cmake
+
+If you want to use "cmake" (see www.cmake.org), type
+
+    cmake . -DCMAKE_INSTALL_PREFIX=/path
+    make
+    make install
+
+As when using the simple configure method described above, "/path" points to
+the installation directory where you want to put the libpng "lib", "include",
+and "bin" subdirectories.
+
+V. Directory structure
+
+You can rename the directories that you downloaded (they
+might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.8"
+or "zlib128") so that you have directories called "zlib" and "libpng".
+
+Your directory structure should look like this:
+
+    .. (the parent directory)
+      libpng (this directory)
+          INSTALL (this file)
+          README
+          *.h, *.c  => libpng source files
+          CMakeLists.txt    =>  "cmake" script
+          configuration files:
+             configure.ac, configure, Makefile.am, Makefile.in,
+             autogen.sh, config.guess, ltmain.sh, missing, libpng.pc.in,
+             libpng-config.in, aclocal.m4, config.h.in, config.sub,
+             depcomp, install-sh, mkinstalldirs, test-pngtest.sh
+          contrib
+             arm-neon, conftest, examples, gregbook, libtests, pngminim,
+             pngminus, pngsuite, tools, visupng
+          projects
+             cbuilder5, owatcom, visualc71, vstudio, xcode
+          scripts
+             makefile.*
+             *.def (module definition files)
+             etc.
+          pngtest.png
+          etc.
+      zlib
+          README, *.h, *.c contrib, etc.
+
+If the line endings in the files look funny, you may wish to get the other
+distribution of libpng.  It is available in both tar.gz (UNIX style line
+endings) and zip (DOS style line endings) formats.
+
+VI. Building with project files
+
+If you are building libpng with MSVC, you can enter the
+libpng projects\visualc71 or vstudio directory and follow the instructions
+in README.txt.
+
+Otherwise enter the zlib directory and follow the instructions in zlib/README,
+then come back here and run "configure" or choose the appropriate
+makefile.sys in the scripts directory.
+
+VII. Building with makefiles
+
+Copy the file (or files) that you need from the
+scripts directory into this directory, for example
+
+MSDOS example:
+
+    copy scripts\makefile.msc makefile
+    copy scripts\pnglibconf.h.prebuilt pnglibconf.h
+
+UNIX example:
+
+    cp scripts/makefile.std makefile
+    cp scripts/pnglibconf.h.prebuilt pnglibconf.h
+
+Read the makefile to see if you need to change any source or
+target directories to match your preferences.
+
+Then read pnglibconf.dfa to see if you want to make any configuration
+changes.
+
+Then just run "make" which will create the libpng library in
+this directory and "make test" which will run a quick test that reads
+the "pngtest.png" file and writes a "pngout.png" file that should be
+identical to it.  Look for "9782 zero samples" in the output of the
+test.  For more confidence, you can run another test by typing
+"pngtest pngnow.png" and looking for "289 zero samples" in the output.
+Also, you can run "pngtest -m contrib/pngsuite/*.png" and compare
+your output with the result shown in contrib/pngsuite/README.
+
+Most of the makefiles will allow you to run "make install" to
+put the library in its final resting place (if you want to
+do that, run "make install" in the zlib directory first if necessary).
+Some also allow you to run "make test-installed" after you have
+run "make install".
+
+VIII. Configuring libpng for 16-bit platforms
+
+You will want to look into zconf.h to tell zlib (and thus libpng) that
+it cannot allocate more than 64K at a time.  Even if you can, the memory
+won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.
+
+IX. Configuring for DOS
+
+For DOS users who only have access to the lower 640K, you will
+have to limit zlib's memory usage via a png_set_compression_mem_level()
+call.  See zlib.h or zconf.h in the zlib library for more information.
+
+X. Configuring for Medium Model
+
+Libpng's support for medium model has been tested on most of the popular
+compilers.  Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
+defined, and FAR gets defined to far in pngconf.h, and you should be
+all set.  Everything in the library (except for zlib's structure) is
+expecting far data.  You must use the typedefs with the p or pp on
+the end for pointers (or at least look at them and be careful).  Make
+note that the rows of data are defined as png_bytepp, which is
+an "unsigned char far * far *".
+
+XI. Prepending a prefix to exported symbols
+
+Starting with libpng-1.6.0, you can configure libpng (when using the
+"configure" script) to prefix all exported symbols by means of the
+configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any
+string beginning with a letter and containing only uppercase
+and lowercase letters, digits, and the underscore (i.e., a C language
+identifier).  This creates a set of macros in pnglibconf.h, so this is
+transparent to applications; their function calls get transformed by
+the macros to use the modified names.
+
+XII. Configuring for compiler xxx:
+
+All includes for libpng are in pngconf.h.  If you need to add, change
+or delete an include, this is the place to do it.
+The includes that are not needed outside libpng are placed in pngpriv.h,
+which is only used by the routines inside libpng itself.
+The files in libpng proper only include pngpriv.h and png.h, which
+in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
+As of libpng-1.5.0, pngpriv.h also includes three other private header
+files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
+that previously appeared in the public headers.
+
+XIII. Removing unwanted object code
+
+There are a bunch of #define's in pngconf.h that control what parts of
+libpng are compiled.  All the defines end in _SUPPORTED.  If you are
+never going to use a capability, you can change the #define to #undef
+before recompiling libpng and save yourself code and data space, or
+you can turn off individual capabilities with defines that begin with
+"PNG_NO_".
+
+In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
+
+You can also turn all of the transforms and ancillary chunk capabilities
+off en masse with compiler directives that define
+PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
+or all four, along with directives to turn on any of the capabilities that
+you do want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the
+extra transformations but still leave the library fully capable of reading
+and writing PNG files with all known public chunks. Use of the
+PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
+that is incapable of reading or writing ancillary chunks.  If you are
+not using the progressive reading capability, you can turn that off
+with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
+capability, which you'll still have).
+
+All the reading and writing specific code are in separate files, so the
+linker should only grab the files it needs.  However, if you want to
+make sure, or if you are building a stand alone library, all the
+reading files start with "pngr" and all the writing files start with "pngw".
+The files that don't match either (like png.c, pngtrans.c, etc.)
+are used for both reading and writing, and always need to be included.
+The progressive reader is in pngpread.c
+
+If you are creating or distributing a dynamically linked library (a .so
+or DLL file), you should not remove or disable any parts of the library,
+as this will cause applications linked with different versions of the
+library to fail if they call functions not available in your library.
+The size of the library itself should not be an issue, because only
+those sections that are actually used will be loaded into memory.
+
+XIV. Enabling or disabling hardware optimizations
+
+Certain hardware capabilities, such as the Intel SSE instructions,
+are normally detected at run time. Enable them with configure options
+such as one of
+
+   --enable-arm-neon=yes
+   --enable-mips-msa=yes
+   --enable-intel-sse=yes
+   --enable-powerpc-vsx=yes
+
+or enable them all at once with
+
+   --enable-hardware-optimizations=yes
+
+or, if you are not using "configure", you can use one
+or more of
+
+   CPPFLAGS += "-DPNG_ARM_NEON"
+   CPPFLAGS += "-DPNG_MIPS_MSA"
+   CPPFLAGS += "-DPNG_INTEL_SSE"
+   CPPFLAGS += "-DPNG_POWERPC_VSX"
+
+See for example scripts/makefile.linux-opt
+
+If you wish to avoid using them,
+you can disable them via the configure option
+
+   --disable-hardware-optimizations
+
+to disable them all, or
+
+   --enable-intel-sse=no
+
+to disable a particular one,
+or via compiler-command options such as
+
+   CPPFLAGS += "-DPNG_ARM_NEON_OPT=0, -DPNG_MIPS_MSA_OPT=0,
+   -DPNG_INTEL_SSE_OPT=0, -DPNG_POWERPC_VSX_OPT=0"
+
+If you are using cmake, hardware optimizations are "on"
+by default. To disable them, use
+
+    cmake . -DPNG_ARM_NEON=no -DPNG_INTEL_SSE=no \
+            -DPNG_MIPS_MSA=no -DPNG_POWERPC_VSX=no
+
+or disable them all at once with
+
+    cmake . -DPNG_HARDWARE_OPTIMIZATIONS=no
+
+XV. Changes to the build and configuration of libpng in libpng-1.5.x
+
+Details of internal changes to the library code can be found in the CHANGES
+file and in the GIT repository logs.  These will be of no concern to the vast
+majority of library users or builders; however, the few who configure libpng
+to a non-default feature set may need to change how this is done.
+
+There should be no need for library builders to alter build scripts if
+these use the distributed build support - configure or the makefiles -
+however, users of the makefiles may care to update their build scripts
+to build pnglibconf.h where the corresponding makefile does not do so.
+
+Building libpng with a non-default configuration has changed completely.
+The old method using pngusr.h should still work correctly even though the
+way pngusr.h is used in the build has been changed; however, library
+builders will probably want to examine the changes to take advantage of
+new capabilities and to simplify their build system.
+
+A. Specific changes to library configuration capabilities
+
+The exact mechanism used to control attributes of API functions has
+changed.  A single set of operating system independent macro definitions
+is used and operating system specific directives are defined in
+pnglibconf.h
+
+As part of this the mechanism used to choose procedure call standards on
+those systems that allow a choice has been changed.  At present this only
+affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
+running on Intel processors.  As before, PNGAPI is defined where required
+to control the exported API functions; however, two new macros, PNGCBAPI
+and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
+(PNGCAPI) for functions that must match a C library prototype (currently
+only png_longjmp_ptr, which must match the C longjmp function.)  The new
+approach is documented in pngconf.h
+
+Despite these changes, libpng 1.5.0 only supports the native C function
+calling standard on those platforms tested so far ("__cdecl" on Microsoft
+Windows).  This is because the support requirements for alternative
+calling conventions seem to no longer exist.  Developers who find it
+necessary to set PNG_API_RULE to 1 should advise the mailing list
+(png-mng-implement) of this and library builders who use Openwatcom and
+therefore set PNG_API_RULE to 2 should also contact the mailing list.
+
+B. Changes to the configuration mechanism
+
+Prior to libpng-1.5.0 library builders who needed to configure libpng
+had either to modify the exported pngconf.h header file to add system
+specific configuration or had to write feature selection macros into
+pngusr.h and cause this to be included into pngconf.h by defining
+PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
+application built without PNG_USER_CONFIG defined would see the
+unmodified, default, libpng API and thus would probably fail to link.
+
+These mechanisms still work in the configure build and in any makefile
+build that builds pnglibconf.h, although the feature selection macros
+have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
+processed only once, at the time the exported header file pnglibconf.h is
+built.  pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
+after the build of pnglibconf.h and it is never included in an application
+build.
+
+The formerly used alternative of adding a list of feature macros to the
+CPPFLAGS setting in the build also still works; however, the macros will be
+copied to pnglibconf.h and this may produce macro redefinition warnings
+when the individual C files are compiled.
+
+All configuration now only works if pnglibconf.h is built from
+scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
+(the original author of awk) maintains C source code of that awk and this
+and all known later implementations (often called by subtly different
+names - nawk and gawk for example) are adequate to build pnglibconf.h.
+The Sun Microsystems (now Oracle) program 'awk' is an earlier version
+and does not work; this may also apply to other systems that have a
+functioning awk called 'nawk'.
+
+Configuration options are now documented in scripts/pnglibconf.dfa.  This
+file also includes dependency information that ensures a configuration is
+consistent; that is, if a feature is switched off, dependent features are
+also switched off.  As a recommended alternative to using feature macros in
+pngusr.h a system builder may also define equivalent options in pngusr.dfa
+(or, indeed, any file) and add that to the configuration by setting
+DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
+how to do this, and also illustrate a case where pngusr.h is still required.
+
+After you have built libpng, the definitions that were recorded in
+pnglibconf.h are available to your application (pnglibconf.h is included
+in png.h and gets installed alongside png.h and pngconf.h in your
+$PREFIX/include directory).  Do not edit pnglibconf.h after you have built
+libpng, because than the settings would not accurately reflect the settings
+that were used to build libpng.
+
+XVI. Setjmp/longjmp issues
+
+Libpng uses setjmp()/longjmp() for error handling.  Unfortunately setjmp()
+is known to be not thread-safe on some platforms and we don't know of
+any platform where it is guaranteed to be thread-safe.  Therefore, if
+your application is going to be using multiple threads, you should
+configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with
+-DPNG_NO_SETJMP on your compile line, or with
+
+    #undef PNG_SETJMP_SUPPORTED
+
+in your pnglibconf.h or pngusr.h.
+
+Starting with libpng-1.6.0, the library included a "simplified API".
+This requires setjmp/longjmp, so you must either build the library
+with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
+and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
+
+XVII. Common linking failures
+
+If your application fails to find libpng or zlib entries while linking:
+
+  Be sure "-lz" appears after "-lpng" on your linking command.
+
+  Be sure you have built libpng, zlib, and your application for the
+  same platform (e.g., 32-bit or 64-bit).
+
+  If you are using the vstudio project, observe the WARNING in
+  project/vstudio/README.txt.
+
+XVIII. Other sources of information about libpng:
+
+Further information can be found in the README and libpng-manual.txt
+files, in the individual makefiles, in png.h, and the manual pages
+libpng.3 and png.5.
+
+Copyright (c) 1998-2002,2006-2016 Glenn Randers-Pehrson
+This document is released under the libpng license.
+For conditions of distribution and use, see the disclaimer
+and license in png.h.
diff --git a/extern/libpng/LICENSE b/extern/libpng/LICENSE
new file mode 100644
index 0000000000..e0c5b531cf
--- /dev/null
+++ b/extern/libpng/LICENSE
@@ -0,0 +1,134 @@
+COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
+=========================================
+
+PNG Reference Library License version 2
+---------------------------------------
+
+ * Copyright (c) 1995-2019 The PNG Reference Library Authors.
+ * Copyright (c) 2018-2019 Cosmin Truta.
+ * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson.
+ * Copyright (c) 1996-1997 Andreas Dilger.
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+
+The software is supplied "as is", without warranty of any kind,
+express or implied, including, without limitation, the warranties
+of merchantability, fitness for a particular purpose, title, and
+non-infringement.  In no event shall the Copyright owners, or
+anyone distributing the software, be liable for any damages or
+other liability, whether in contract, tort or otherwise, arising
+from, out of, or in connection with the software, or the use or
+other dealings in the software, even if advised of the possibility
+of such damage.
+
+Permission is hereby granted to use, copy, modify, and distribute
+this software, or portions hereof, for any purpose, without fee,
+subject to the following restrictions:
+
+ 1. The origin of this software must not be misrepresented; you
+    must not claim that you wrote the original software.  If you
+    use this software in a product, an acknowledgment in the product
+    documentation would be appreciated, but is not required.
+
+ 2. Altered source versions must be plainly marked as such, and must
+    not be misrepresented as being the original software.
+
+ 3. This Copyright notice may not be removed or altered from any
+    source or altered source distribution.
+
+
+PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
+-----------------------------------------------------------------------
+
+libpng versions 1.0.7, July 1, 2000, through 1.6.35, July 15, 2018 are
+Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson, are
+derived from libpng-1.0.6, and are distributed according to the same
+disclaimer and license as libpng-1.0.6 with the following individuals
+added to the list of Contributing Authors:
+
+    Simon-Pierre Cadieux
+    Eric S. Raymond
+    Mans Rullgard
+    Cosmin Truta
+    Gilles Vollant
+    James Yu
+    Mandar Sahastrabuddhe
+    Google Inc.
+    Vadim Barkov
+
+and with the following additions to the disclaimer:
+
+    There is no warranty against interference with your enjoyment of
+    the library or against infringement.  There is no warranty that our
+    efforts or the library will fulfill any of your particular purposes
+    or needs.  This library is provided with all faults, and the entire
+    risk of satisfactory quality, performance, accuracy, and effort is
+    with the user.
+
+Some files in the "contrib" directory and some configure-generated
+files that are distributed with libpng have other copyright owners, and
+are released under other open source licenses.
+
+libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
+Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
+libpng-0.96, and are distributed according to the same disclaimer and
+license as libpng-0.96, with the following individuals added to the
+list of Contributing Authors:
+
+    Tom Lane
+    Glenn Randers-Pehrson
+    Willem van Schaik
+
+libpng versions 0.89, June 1996, through 0.96, May 1997, are
+Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
+and are distributed according to the same disclaimer and license as
+libpng-0.88, with the following individuals added to the list of
+Contributing Authors:
+
+    John Bowler
+    Kevin Bracey
+    Sam Bushell
+    Magnus Holmgren
+    Greg Roelofs
+    Tom Tanner
+
+Some files in the "scripts" directory have other copyright owners,
+but are released under this license.
+
+libpng versions 0.5, May 1995, through 0.88, January 1996, are
+Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+
+For the purposes of this copyright and license, "Contributing Authors"
+is defined as the following set of individuals:
+
+    Andreas Dilger
+    Dave Martindale
+    Guy Eric Schalnat
+    Paul Schmidt
+    Tim Wegner
+
+The PNG Reference Library is supplied "AS IS".  The Contributing
+Authors and Group 42, Inc. disclaim all warranties, expressed or
+implied, including, without limitation, the warranties of
+merchantability and of fitness for any purpose.  The Contributing
+Authors and Group 42, Inc. assume no liability for direct, indirect,
+incidental, special, exemplary, or consequential damages, which may
+result from the use of the PNG Reference Library, even if advised of
+the possibility of such damage.
+
+Permission is hereby granted to use, copy, modify, and distribute this
+source code, or portions hereof, for any purpose, without fee, subject
+to the following restrictions:
+
+ 1. The origin of this source code must not be misrepresented.
+
+ 2. Altered versions must be plainly marked as such and must not
+    be misrepresented as being the original source.
+
+ 3. This Copyright notice may not be removed or altered from any
+    source or altered source distribution.
+
+The Contributing Authors and Group 42, Inc. specifically permit,
+without fee, and encourage the use of this source code as a component
+to supporting the PNG file format in commercial products.  If you use
+this source code in a product, acknowledgment is not required but would
+be appreciated.
diff --git a/extern/libpng/Makefile.am b/extern/libpng/Makefile.am
new file mode 100644
index 0000000000..4f621aa4d6
--- /dev/null
+++ b/extern/libpng/Makefile.am
@@ -0,0 +1,393 @@
+# Makefile.am, the source file for Makefile.in (and hence Makefile), is
+#
+# Copyright (c) 2018 Cosmin Truta
+# Copyright (c) 2004-2016 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+
+ACLOCAL_AMFLAGS = -I scripts
+
+# test programs - run on make check, make distcheck
+check_PROGRAMS= pngtest pngunknown pngstest pngvalid pngimage pngcp
+if HAVE_CLOCK_GETTIME
+check_PROGRAMS += timepng
+endif
+
+# Utilities - installed
+bin_PROGRAMS= pngfix png-fix-itxt
+
+# This ensures that pnglibconf.h gets built at the start of 'make all' or
+# 'make check', but it does not add dependencies to the individual programs,
+# this is done below.
+#
+# IMPORTANT: always add the object modules of new programs to the list below
+# because otherwise the sequence 'configure; make new-program' will *sometimes*
+# result in the installed (system) pnglibconf.h being used and the result is
+# always wrong and always very confusing.
+BUILT_SOURCES = pnglibconf.h
+
+pngtest_SOURCES = pngtest.c
+pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngvalid_SOURCES = contrib/libtests/pngvalid.c
+pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngstest_SOURCES = contrib/libtests/pngstest.c
+pngstest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngunknown_SOURCES = contrib/libtests/pngunknown.c
+pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngimage_SOURCES = contrib/libtests/pngimage.c
+pngimage_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+timepng_SOURCES = contrib/libtests/timepng.c
+timepng_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngfix_SOURCES = contrib/tools/pngfix.c
+pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c
+
+pngcp_SOURCES = contrib/tools/pngcp.c
+pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+# Generally these are single line shell scripts to run a test with a particular
+# set of parameters:
+TESTS =\
+   tests/pngtest\
+   tests/pngtest-badpngs\
+   tests/pngvalid-gamma-16-to-8 tests/pngvalid-gamma-alpha-mode\
+   tests/pngvalid-gamma-background tests/pngvalid-gamma-expand16-alpha-mode\
+   tests/pngvalid-gamma-expand16-background\
+   tests/pngvalid-gamma-expand16-transform tests/pngvalid-gamma-sbit\
+   tests/pngvalid-gamma-threshold tests/pngvalid-gamma-transform\
+   tests/pngvalid-progressive-size\
+   tests/pngvalid-progressive-interlace-standard\
+   tests/pngvalid-transform\
+   tests/pngvalid-progressive-standard tests/pngvalid-standard\
+   tests/pngstest-1.8 tests/pngstest-1.8-alpha tests/pngstest-linear\
+   tests/pngstest-linear-alpha tests/pngstest-none tests/pngstest-none-alpha\
+   tests/pngstest-sRGB tests/pngstest-sRGB-alpha tests/pngunknown-IDAT\
+   tests/pngunknown-discard tests/pngunknown-if-safe tests/pngunknown-sAPI\
+   tests/pngunknown-sTER tests/pngunknown-save tests/pngunknown-vpAg\
+   tests/pngimage-quick tests/pngimage-full
+
+# man pages
+dist_man_MANS= libpng.3 libpngpf.3 png.5
+
+# generate the -config scripts if required
+binconfigs= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
+EXTRA_SCRIPTS= libpng-config libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
+bin_SCRIPTS= @binconfigs@
+
+# rules to build libpng, only build the old library on request
+lib_LTLIBRARIES=libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+# EXTRA_LTLIBRARIES= libpng.la
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c\
+	pngget.c pngmem.c pngpread.c pngread.c pngrio.c pngrtran.c pngrutil.c\
+	pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c\
+	png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h pngusr.dfa
+
+if PNG_ARM_NEON
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += arm/arm_init.c\
+	arm/filter_neon.S arm/filter_neon_intrinsics.c \
+	arm/palette_neon_intrinsics.c
+endif
+
+if PNG_MIPS_MSA
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += mips/mips_init.c\
+	mips/filter_msa_intrinsics.c
+endif
+
+if PNG_INTEL_SSE
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += intel/intel_init.c\
+	intel/filter_sse2_intrinsics.c
+endif
+
+if PNG_POWERPC_VSX
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += powerpc/powerpc_init.c\
+        powerpc/filter_vsx_intrinsics.c
+endif
+
+nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
+
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined -export-dynamic \
+	-version-number @PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0
+
+if HAVE_LD_VERSION_SCRIPT
+#   Versioned symbols and restricted exports
+if HAVE_SOLARIS_LD
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,-M -Wl,libpng.vers
+else
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,--version-script=libpng.vers
+endif
+
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.vers
+else
+#   Only restricted exports when possible
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -export-symbols libpng.sym
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.sym
+endif
+
+#distribute headers in /usr/include/libpng/*
+pkgincludedir= $(includedir)/$(PNGLIB_BASENAME)
+pkginclude_HEADERS= png.h pngconf.h
+nodist_pkginclude_HEADERS= pnglibconf.h
+
+# pkg-config stuff, note that libpng.pc is always required in order
+# to get the correct library
+pkgconfigdir = @pkgconfigdir@
+pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc
+
+# Extra source distribution files, '${srcdir}' is used below to stop build files
+# from those directories being included.  This only works if the configure is
+# not done in the source directory!
+EXTRA_DIST= \
+	ANNOUNCE AUTHORS CHANGES INSTALL LICENSE README TODO TRADEMARK \
+	pngtest.png pngbar.png pngnow.png pngbar.jpg autogen.sh \
+	${srcdir}/contrib ${srcdir}/projects ${srcdir}/scripts \
+	$(TESTS) $(XFAIL_TESTS) tests/pngstest \
+	CMakeLists.txt example.c libpng-manual.txt
+
+SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk
+
+CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
+	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
+	check.new pnglibconf.h pngprefix.h symbols.new pngtest-log.txt \
+	pnglibconf.out pnglibconf.c pnglibconf.pre pnglibconf.dfn \
+	$(SCRIPT_CLEANFILES)
+
+MAINTAINERCLEANFILES = Makefile.in aclocal.m4 config.guess config.h.in \
+config.sub configure depcomp install-sh ltmain.sh missing
+
+# PNG_COPTS give extra options for the C compiler to be used on all compilation
+# steps (unless targe_CFLAGS is specified; that will take precedence over
+# AM_CFLAGS)
+PNG_COPTS = @PNG_COPTS@
+AM_CFLAGS = ${PNG_COPTS}
+
+# DFNCPP is normally just CPP - the C preprocessor - but on Solaris and maybe
+# other operating systems (NeXT?) the C preprocessor selected by configure
+# checks input tokens for validity - effectively it performs part of the ANSI-C
+# parsing - and therefore fails with the .df files.  configure.ac has special
+# checks for this and sets DFNCPP appropriately.
+DFNCPP = @DFNCPP@
+
+SUFFIXES = .chk .out
+
+$(PNGLIB_BASENAME).pc: libpng.pc
+	cp libpng.pc $@
+
+$(PNGLIB_BASENAME)-config: libpng-config
+	cp libpng-config $@
+
+scripts/sym.out scripts/vers.out: png.h pngconf.h pnglibconf.h
+scripts/prefix.out: png.h pngconf.h pnglibconf.out
+scripts/symbols.out: png.h pngconf.h $(srcdir)/scripts/pnglibconf.h.prebuilt
+scripts/intprefix.out: pnglibconf.h
+
+libpng.sym: scripts/sym.out
+	rm -f $@
+	cp $? $@
+libpng.vers: scripts/vers.out
+	rm -f $@
+	cp $? $@
+
+if DO_PNG_PREFIX
+# Rename functions in scripts/prefix.out with a PNG_PREFIX prefix.
+# Rename macros in scripts/macro.lst from PNG_PREFIXpng_ to PNG_ (the actual
+# implementation of the macro).
+pnglibconf.h: pnglibconf.out scripts/prefix.out scripts/macro.lst
+	rm -f $@
+	$(AWK) 's==0 && NR>1{print prev}\
+	   s==0{prev=$$0}\
+	   s==1{print "#define", $$1, "@PNG_PREFIX@" $$1}\
+	   s==2{print "#define @PNG_PREFIX@png_" $$1, "PNG_" $$1}\
+	   END{print prev}' s=0 pnglibconf.out s=1 scripts/prefix.out\
+	   s=2 ${srcdir}/scripts/macro.lst >pnglibconf.tf8
+	mv pnglibconf.tf8 $@
+
+pngprefix.h: scripts/intprefix.out
+	rm -f pngprefix.tf1
+	$(AWK) '{print "#define", $$1, "@PNG_PREFIX@" $$1}' $? >pngprefix.tf1
+	mv pngprefix.tf1 $@
+else
+pnglibconf.h: pnglibconf.out
+	rm -f $@
+	cp $? $@
+
+pngprefix.h: # is empty
+	:>$@
+endif
+
+$(srcdir)/scripts/pnglibconf.h.prebuilt:
+	@echo "Attempting to build $@" >&2
+	@echo "This is a machine generated file, but if you want to make" >&2
+	@echo "a new one simply make 'scripts/pnglibconf.out', copy that" >&2
+	@echo "AND set PNG_ZLIB_VERNUM to 0 (you MUST do this)" >&2
+	@exit 1
+
+# The following is necessary to ensure that the local pnglibconf.h is used, not
+# an installed one (this can happen immediately after on a clean system if
+# 'make test' is the first thing the user does.)  Only files which include
+# one of the png source files (typically png.h or pngpriv.h) need to be listed
+# here:
+pngtest.o: pnglibconf.h
+
+contrib/libtests/makepng.o: pnglibconf.h
+contrib/libtests/pngstest.o: pnglibconf.h
+contrib/libtests/pngunknown.o: pnglibconf.h
+contrib/libtests/pngimage.o: pnglibconf.h
+contrib/libtests/pngvalid.o: pnglibconf.h
+contrib/libtests/readpng.o: pnglibconf.h
+contrib/libtests/tarith.o: pnglibconf.h
+contrib/libtests/timepng.o: pnglibconf.h
+
+contrib/tools/makesRGB.o: pnglibconf.h
+contrib/tools/pngfix.o: pnglibconf.h
+contrib/tools/pngcp.o: pnglibconf.h
+
+# We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
+# be built with PNG_USE_READ_MACROS; this prevents the read macros from
+# interfering with the symbol file format.
+SYMBOL_CFLAGS = -DPNGLIB_LIBNAME='PNG@PNGLIB_MAJOR@@PNGLIB_MINOR@_0'\
+		-DPNGLIB_VERSION='@PNGLIB_VERSION@'\
+		-DSYMBOL_PREFIX='$(SYMBOL_PREFIX)'\
+		-DPNG_NO_USE_READ_MACROS -DPNG_BUILDING_SYMBOL_TABLE
+
+if DO_PNG_PREFIX
+SYMBOL_CFLAGS += -DPNG_PREFIX='@PNG_PREFIX@'
+endif
+
+.c.out:
+	rm -f $@ $*.tf[12]
+	test -d scripts || mkdir scripts || test -d scripts
+	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES)\
+	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $< > $*.tf1
+	$(AWK) -f "${srcdir}/scripts/dfn.awk" out="$*.tf2" $*.tf1 1>&2
+	rm -f $*.tf1
+	mv $*.tf2 $@
+
+# The .c file for pnglibconf.h is machine generated
+pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+	rm -f $@ $*.tf[45]
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf4 version=search\
+	    ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+	    ${srcdir}/pngusr.dfa $(DFA_XTRA) 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf5 $*.tf4 1>&2
+	rm $*.tf4
+	mv $*.tf5 $@
+
+# Symbol checks (.def and .out files should match)
+scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.out
+
+.out.chk:
+	rm -f $@ $*.new
+	$(AWK) -f ${srcdir}/scripts/checksym.awk ${srcdir}/scripts/${*F}.def\
+	    of="$*.new" $< >&2
+	mv $*.new $@
+
+# used on demand to regenerate the standard header, CPPFLAGS should
+# be empty - no non-standard defines
+scripts/pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
+	rm -f $@ pnglibconf.tf[67]
+	test -z "$(CPPFLAGS)"
+	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf6\
+	    logunsupported=1 version=search ${srcdir}/pngconf.h -\
+	    ${srcdir}/scripts/pnglibconf.dfa 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf7\
+	    pnglibconf.tf6 1>&2
+	rm pnglibconf.tf6
+	mv pnglibconf.tf7 $@
+
+$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS): png.h pngconf.h \
+	pnglibconf.h pngpriv.h pngdebug.h pnginfo.h pngstruct.h pngprefix.h
+
+test: check-am
+
+# Extra checks
+check: scripts/symbols.chk
+
+# Don't distribute the generated script files
+dist-hook:
+	cd '$(top_distdir)'; rm -f $(SCRIPT_CLEANFILES)
+
+# Make links between installed files with release-specific names and the generic
+# file names.  If this install rule is run the generic names will be deleted and
+# recreated - this has obvious issues for systems with multiple installations.
+
+install-header-links:
+	@set -ex; cd '$(DESTDIR)$(includedir)'; for f in $(HEADERS); do \
+	   rm -f "$$f"; $(LN_S) "$(PNGLIB_BASENAME)/$$f" "$$f"; done
+
+uninstall-header-links:
+	cd '$(DESTDIR)$(includedir)'; rm -f $(HEADERS)
+
+install-libpng-pc:
+	@set -ex; cd '$(DESTDIR)$(pkgconfigdir)'; rm -f libpng.pc; \
+	   $(LN_S) '$(PNGLIB_BASENAME).pc' libpng.pc
+
+uninstall-libpng-pc:
+	rm -f '$(DESTDIR)$(pkgconfigdir)/libpng.pc'
+
+# EXT_LIST is a list of the possibly library directory extensions, this exists
+# because we can't find a good way of discovering the file extensions that are
+# actually installed on a given system, so instead we check for every extension
+# we have seen.
+
+EXT_LIST = a dll.a so so.@PNGLIB_MAJOR@@PNGLIB_MINOR@.@PNGLIB_RELEASE@ la sl dylib
+
+install-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)';\
+	for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext";\
+           if test -f "$(PNGLIB_BASENAME).$$ext"; then\
+              $(LN_S) "$(PNGLIB_BASENAME).$$ext" "libpng.$$ext" || exit 1;\
+           fi;\
+	done
+
+uninstall-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)'; for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext"; done
+
+install-libpng-config:
+	@set -ex; cd '$(DESTDIR)$(bindir)'; rm -f libpng-config; \
+	   $(LN_S) '$(PNGLIB_BASENAME)-config' libpng-config
+
+uninstall-libpng-config:
+	rm -f '$(DESTDIR)$(bindir)/libpng-config'
+
+if DO_INSTALL_LINKS
+# If --enable-unversioned-links is specified the header and lib file links
+# will be automatically made on a 'make install':
+
+install-data-hook: install-header-links
+uninstall-hook: uninstall-header-links
+install-exec-hook: install-library-links
+uninstall-hook: uninstall-library-links
+endif
+
+if DO_INSTALL_LIBPNG_PC
+# Likewise, --install-pc causes libpng.pc to be constructed:
+
+install-data-hook: install-libpng-pc
+uninstall-hook: uninstall-libpng-pc
+endif
+
+if DO_INSTALL_LIBPNG_CONFIG
+# And --install-config:
+
+install-exec-hook: install-libpng-config
+uninstall-hook: uninstall-libpng-config
+endif
+
+# The following addition ensures that 'make all' always builds the test programs
+# too.  It used to, but some change either in libpng or configure stopped this
+# working.
+all-am: $(check_PROGRAMS)
diff --git a/extern/libpng/Makefile.in b/extern/libpng/Makefile.in
new file mode 100644
index 0000000000..81ac1c8552
--- /dev/null
+++ b/extern/libpng/Makefile.in
@@ -0,0 +1,2428 @@
+# Makefile.in generated by automake 1.16.1 from Makefile.am.
+# @configure_input@
+
+# Copyright (C) 1994-2018 Free Software Foundation, Inc.
+
+# This Makefile.in is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY, to the extent permitted by law; without
+# even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE.
+
+@SET_MAKE@
+
+# Makefile.am, the source file for Makefile.in (and hence Makefile), is
+#
+# Copyright (c) 2018 Cosmin Truta
+# Copyright (c) 2004-2016 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+
+
+
+
+VPATH = @srcdir@
+am__is_gnu_make = { \
+  if test -z '$(MAKELEVEL)'; then \
+    false; \
+  elif test -n '$(MAKE_HOST)'; then \
+    true; \
+  elif test -n '$(MAKE_VERSION)' && test -n '$(CURDIR)'; then \
+    true; \
+  else \
+    false; \
+  fi; \
+}
+am__make_running_with_option = \
+  case $${target_option-} in \
+      ?) ;; \
+      *) echo "am__make_running_with_option: internal error: invalid" \
+              "target option '$${target_option-}' specified" >&2; \
+         exit 1;; \
+  esac; \
+  has_opt=no; \
+  sane_makeflags=$$MAKEFLAGS; \
+  if $(am__is_gnu_make); then \
+    sane_makeflags=$$MFLAGS; \
+  else \
+    case $$MAKEFLAGS in \
+      *\\[\ \	]*) \
+        bs=\\; \
+        sane_makeflags=`printf '%s\n' "$$MAKEFLAGS" \
+          | sed "s/$$bs$$bs[$$bs $$bs	]*//g"`;; \
+    esac; \
+  fi; \
+  skip_next=no; \
+  strip_trailopt () \
+  { \
+    flg=`printf '%s\n' "$$flg" | sed "s/$$1.*$$//"`; \
+  }; \
+  for flg in $$sane_makeflags; do \
+    test $$skip_next = yes && { skip_next=no; continue; }; \
+    case $$flg in \
+      *=*|--*) continue;; \
+        -*I) strip_trailopt 'I'; skip_next=yes;; \
+      -*I?*) strip_trailopt 'I';; \
+        -*O) strip_trailopt 'O'; skip_next=yes;; \
+      -*O?*) strip_trailopt 'O';; \
+        -*l) strip_trailopt 'l'; skip_next=yes;; \
+      -*l?*) strip_trailopt 'l';; \
+      -[dEDm]) skip_next=yes;; \
+      -[JT]) skip_next=yes;; \
+    esac; \
+    case $$flg in \
+      *$$target_option*) has_opt=yes; break;; \
+    esac; \
+  done; \
+  test $$has_opt = yes
+am__make_dryrun = (target_option=n; $(am__make_running_with_option))
+am__make_keepgoing = (target_option=k; $(am__make_running_with_option))
+pkgdatadir = $(datadir)/@PACKAGE@
+pkglibdir = $(libdir)/@PACKAGE@
+pkglibexecdir = $(libexecdir)/@PACKAGE@
+am__cd = CDPATH="$${ZSH_VERSION+.}$(PATH_SEPARATOR)" && cd
+install_sh_DATA = $(install_sh) -c -m 644
+install_sh_PROGRAM = $(install_sh) -c
+install_sh_SCRIPT = $(install_sh) -c
+INSTALL_HEADER = $(INSTALL_DATA)
+transform = $(program_transform_name)
+NORMAL_INSTALL = :
+PRE_INSTALL = :
+POST_INSTALL = :
+NORMAL_UNINSTALL = :
+PRE_UNINSTALL = :
+POST_UNINSTALL = :
+build_triplet = @build@
+host_triplet = @host@
+check_PROGRAMS = pngtest$(EXEEXT) pngunknown$(EXEEXT) \
+	pngstest$(EXEEXT) pngvalid$(EXEEXT) pngimage$(EXEEXT) \
+	pngcp$(EXEEXT) $(am__EXEEXT_1)
+@HAVE_CLOCK_GETTIME_TRUE@am__append_1 = timepng
+bin_PROGRAMS = pngfix$(EXEEXT) png-fix-itxt$(EXEEXT)
+@PNG_ARM_NEON_TRUE@am__append_2 = arm/arm_init.c\
+@PNG_ARM_NEON_TRUE@	arm/filter_neon.S arm/filter_neon_intrinsics.c \
+@PNG_ARM_NEON_TRUE@	arm/palette_neon_intrinsics.c
+
+@PNG_MIPS_MSA_TRUE@am__append_3 = mips/mips_init.c\
+@PNG_MIPS_MSA_TRUE@	mips/filter_msa_intrinsics.c
+
+@PNG_INTEL_SSE_TRUE@am__append_4 = intel/intel_init.c\
+@PNG_INTEL_SSE_TRUE@	intel/filter_sse2_intrinsics.c
+
+@PNG_POWERPC_VSX_TRUE@am__append_5 = powerpc/powerpc_init.c\
+@PNG_POWERPC_VSX_TRUE@        powerpc/filter_vsx_intrinsics.c
+
+
+#   Versioned symbols and restricted exports
+@HAVE_LD_VERSION_SCRIPT_TRUE@@HAVE_SOLARIS_LD_TRUE@am__append_6 = -Wl,-M -Wl,libpng.vers
+@HAVE_LD_VERSION_SCRIPT_TRUE@@HAVE_SOLARIS_LD_FALSE@am__append_7 = -Wl,--version-script=libpng.vers
+#   Only restricted exports when possible
+@HAVE_LD_VERSION_SCRIPT_FALSE@am__append_8 = -export-symbols libpng.sym
+@DO_PNG_PREFIX_TRUE@am__append_9 = -DPNG_PREFIX='@PNG_PREFIX@'
+subdir = .
+ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
+am__aclocal_m4_deps = $(top_srcdir)/scripts/libtool.m4 \
+	$(top_srcdir)/scripts/ltoptions.m4 \
+	$(top_srcdir)/scripts/ltsugar.m4 \
+	$(top_srcdir)/scripts/ltversion.m4 \
+	$(top_srcdir)/scripts/lt~obsolete.m4 \
+	$(top_srcdir)/configure.ac
+am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
+	$(ACLOCAL_M4)
+DIST_COMMON = $(srcdir)/Makefile.am $(top_srcdir)/configure \
+	$(am__configure_deps) $(pkginclude_HEADERS) $(am__DIST_COMMON)
+am__CONFIG_DISTCLEAN_FILES = config.status config.cache config.log \
+ configure.lineno config.status.lineno
+mkinstalldirs = $(install_sh) -d
+CONFIG_HEADER = config.h
+CONFIG_CLEAN_FILES = libpng.pc libpng-config
+CONFIG_CLEAN_VPATH_FILES =
+am__installdirs = "$(DESTDIR)$(bindir)" "$(DESTDIR)$(libdir)" \
+	"$(DESTDIR)$(bindir)" "$(DESTDIR)$(man3dir)" \
+	"$(DESTDIR)$(man5dir)" "$(DESTDIR)$(pkgconfigdir)" \
+	"$(DESTDIR)$(pkgincludedir)" "$(DESTDIR)$(pkgincludedir)"
+@HAVE_CLOCK_GETTIME_TRUE@am__EXEEXT_1 = timepng$(EXEEXT)
+PROGRAMS = $(bin_PROGRAMS)
+am__vpath_adj_setup = srcdirstrip=`echo "$(srcdir)" | sed 's|.|.|g'`;
+am__vpath_adj = case $$p in \
+    $(srcdir)/*) f=`echo "$$p" | sed "s|^$$srcdirstrip/||"`;; \
+    *) f=$$p;; \
+  esac;
+am__strip_dir = f=`echo $$p | sed -e 's|^.*/||'`;
+am__install_max = 40
+am__nobase_strip_setup = \
+  srcdirstrip=`echo "$(srcdir)" | sed 's/[].[^$$\\*|]/\\\\&/g'`
+am__nobase_strip = \
+  for p in $$list; do echo "$$p"; done | sed -e "s|$$srcdirstrip/||"
+am__nobase_list = $(am__nobase_strip_setup); \
+  for p in $$list; do echo "$$p $$p"; done | \
+  sed "s| $$srcdirstrip/| |;"' / .*\//!s/ .*/ ./; s,\( .*\)/[^/]*$$,\1,' | \
+  $(AWK) 'BEGIN { files["."] = "" } { files[$$2] = files[$$2] " " $$1; \
+    if (++n[$$2] == $(am__install_max)) \
+      { print $$2, files[$$2]; n[$$2] = 0; files[$$2] = "" } } \
+    END { for (dir in files) print dir, files[dir] }'
+am__base_list = \
+  sed '$$!N;$$!N;$$!N;$$!N;$$!N;$$!N;$$!N;s/\n/ /g' | \
+  sed '$$!N;$$!N;$$!N;$$!N;s/\n/ /g'
+am__uninstall_files_from_dir = { \
+  test -z "$$files" \
+    || { test ! -d "$$dir" && test ! -f "$$dir" && test ! -r "$$dir"; } \
+    || { echo " ( cd '$$dir' && rm -f" $$files ")"; \
+         $(am__cd) "$$dir" && rm -f $$files; }; \
+  }
+LTLIBRARIES = $(lib_LTLIBRARIES)
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD =
+am__libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES_DIST = png.c \
+	pngerror.c pngget.c pngmem.c pngpread.c pngread.c pngrio.c \
+	pngrtran.c pngrutil.c pngset.c pngtrans.c pngwio.c pngwrite.c \
+	pngwtran.c pngwutil.c png.h pngconf.h pngdebug.h pnginfo.h \
+	pngpriv.h pngstruct.h pngusr.dfa arm/arm_init.c \
+	arm/filter_neon.S arm/filter_neon_intrinsics.c \
+	arm/palette_neon_intrinsics.c mips/mips_init.c \
+	mips/filter_msa_intrinsics.c intel/intel_init.c \
+	intel/filter_sse2_intrinsics.c powerpc/powerpc_init.c \
+	powerpc/filter_vsx_intrinsics.c
+am__dirstamp = $(am__leading_dot)dirstamp
+@PNG_ARM_NEON_TRUE@am__objects_1 = arm/arm_init.lo arm/filter_neon.lo \
+@PNG_ARM_NEON_TRUE@	arm/filter_neon_intrinsics.lo \
+@PNG_ARM_NEON_TRUE@	arm/palette_neon_intrinsics.lo
+@PNG_MIPS_MSA_TRUE@am__objects_2 = mips/mips_init.lo \
+@PNG_MIPS_MSA_TRUE@	mips/filter_msa_intrinsics.lo
+@PNG_INTEL_SSE_TRUE@am__objects_3 = intel/intel_init.lo \
+@PNG_INTEL_SSE_TRUE@	intel/filter_sse2_intrinsics.lo
+@PNG_POWERPC_VSX_TRUE@am__objects_4 = powerpc/powerpc_init.lo \
+@PNG_POWERPC_VSX_TRUE@	powerpc/filter_vsx_intrinsics.lo
+am_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS = png.lo pngerror.lo \
+	pngget.lo pngmem.lo pngpread.lo pngread.lo pngrio.lo \
+	pngrtran.lo pngrutil.lo pngset.lo pngtrans.lo pngwio.lo \
+	pngwrite.lo pngwtran.lo pngwutil.lo $(am__objects_1) \
+	$(am__objects_2) $(am__objects_3) $(am__objects_4)
+nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS =
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS =  \
+	$(am_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS) \
+	$(nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS)
+AM_V_lt = $(am__v_lt_@AM_V@)
+am__v_lt_ = $(am__v_lt_@AM_DEFAULT_V@)
+am__v_lt_0 = --silent
+am__v_lt_1 = 
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LINK = $(LIBTOOL) $(AM_V_lt) \
+	--tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=link \
+	$(CCLD) $(AM_CFLAGS) $(CFLAGS) \
+	$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS) $(LDFLAGS) -o \
+	$@
+am_png_fix_itxt_OBJECTS = contrib/tools/png-fix-itxt.$(OBJEXT)
+png_fix_itxt_OBJECTS = $(am_png_fix_itxt_OBJECTS)
+png_fix_itxt_LDADD = $(LDADD)
+am_pngcp_OBJECTS = contrib/tools/pngcp.$(OBJEXT)
+pngcp_OBJECTS = $(am_pngcp_OBJECTS)
+pngcp_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+am_pngfix_OBJECTS = contrib/tools/pngfix.$(OBJEXT)
+pngfix_OBJECTS = $(am_pngfix_OBJECTS)
+pngfix_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+am_pngimage_OBJECTS = contrib/libtests/pngimage.$(OBJEXT)
+pngimage_OBJECTS = $(am_pngimage_OBJECTS)
+pngimage_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+am_pngstest_OBJECTS = contrib/libtests/pngstest.$(OBJEXT)
+pngstest_OBJECTS = $(am_pngstest_OBJECTS)
+pngstest_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+am_pngtest_OBJECTS = pngtest.$(OBJEXT)
+pngtest_OBJECTS = $(am_pngtest_OBJECTS)
+pngtest_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+am_pngunknown_OBJECTS = contrib/libtests/pngunknown.$(OBJEXT)
+pngunknown_OBJECTS = $(am_pngunknown_OBJECTS)
+pngunknown_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+am_pngvalid_OBJECTS = contrib/libtests/pngvalid.$(OBJEXT)
+pngvalid_OBJECTS = $(am_pngvalid_OBJECTS)
+pngvalid_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+am_timepng_OBJECTS = contrib/libtests/timepng.$(OBJEXT)
+timepng_OBJECTS = $(am_timepng_OBJECTS)
+timepng_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+SCRIPTS = $(bin_SCRIPTS)
+AM_V_P = $(am__v_P_@AM_V@)
+am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
+am__v_P_0 = false
+am__v_P_1 = :
+AM_V_GEN = $(am__v_GEN_@AM_V@)
+am__v_GEN_ = $(am__v_GEN_@AM_DEFAULT_V@)
+am__v_GEN_0 = @echo "  GEN     " $@;
+am__v_GEN_1 = 
+AM_V_at = $(am__v_at_@AM_V@)
+am__v_at_ = $(am__v_at_@AM_DEFAULT_V@)
+am__v_at_0 = @
+am__v_at_1 = 
+DEFAULT_INCLUDES = -I.@am__isrc@
+depcomp = $(SHELL) $(top_srcdir)/depcomp
+am__maybe_remake_depfiles = depfiles
+am__depfiles_remade = ./$(DEPDIR)/png.Plo ./$(DEPDIR)/pngerror.Plo \
+	./$(DEPDIR)/pngget.Plo ./$(DEPDIR)/pngmem.Plo \
+	./$(DEPDIR)/pngpread.Plo ./$(DEPDIR)/pngread.Plo \
+	./$(DEPDIR)/pngrio.Plo ./$(DEPDIR)/pngrtran.Plo \
+	./$(DEPDIR)/pngrutil.Plo ./$(DEPDIR)/pngset.Plo \
+	./$(DEPDIR)/pngtest.Po ./$(DEPDIR)/pngtrans.Plo \
+	./$(DEPDIR)/pngwio.Plo ./$(DEPDIR)/pngwrite.Plo \
+	./$(DEPDIR)/pngwtran.Plo ./$(DEPDIR)/pngwutil.Plo \
+	arm/$(DEPDIR)/arm_init.Plo arm/$(DEPDIR)/filter_neon.Plo \
+	arm/$(DEPDIR)/filter_neon_intrinsics.Plo \
+	arm/$(DEPDIR)/palette_neon_intrinsics.Plo \
+	contrib/libtests/$(DEPDIR)/pngimage.Po \
+	contrib/libtests/$(DEPDIR)/pngstest.Po \
+	contrib/libtests/$(DEPDIR)/pngunknown.Po \
+	contrib/libtests/$(DEPDIR)/pngvalid.Po \
+	contrib/libtests/$(DEPDIR)/timepng.Po \
+	contrib/tools/$(DEPDIR)/png-fix-itxt.Po \
+	contrib/tools/$(DEPDIR)/pngcp.Po \
+	contrib/tools/$(DEPDIR)/pngfix.Po \
+	intel/$(DEPDIR)/filter_sse2_intrinsics.Plo \
+	intel/$(DEPDIR)/intel_init.Plo \
+	mips/$(DEPDIR)/filter_msa_intrinsics.Plo \
+	mips/$(DEPDIR)/mips_init.Plo \
+	powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo \
+	powerpc/$(DEPDIR)/powerpc_init.Plo
+am__mv = mv -f
+CPPASCOMPILE = $(CCAS) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) \
+	$(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CCASFLAGS) $(CCASFLAGS)
+LTCPPASCOMPILE = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=compile $(CCAS) $(DEFS) \
+	$(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) \
+	$(AM_CCASFLAGS) $(CCASFLAGS)
+AM_V_CPPAS = $(am__v_CPPAS_@AM_V@)
+am__v_CPPAS_ = $(am__v_CPPAS_@AM_DEFAULT_V@)
+am__v_CPPAS_0 = @echo "  CPPAS   " $@;
+am__v_CPPAS_1 = 
+COMPILE = $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) \
+	$(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
+LTCOMPILE = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) \
+	$(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) \
+	$(AM_CFLAGS) $(CFLAGS)
+AM_V_CC = $(am__v_CC_@AM_V@)
+am__v_CC_ = $(am__v_CC_@AM_DEFAULT_V@)
+am__v_CC_0 = @echo "  CC      " $@;
+am__v_CC_1 = 
+CCLD = $(CC)
+LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
+	$(AM_LDFLAGS) $(LDFLAGS) -o $@
+AM_V_CCLD = $(am__v_CCLD_@AM_V@)
+am__v_CCLD_ = $(am__v_CCLD_@AM_DEFAULT_V@)
+am__v_CCLD_0 = @echo "  CCLD    " $@;
+am__v_CCLD_1 = 
+SOURCES = $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES) \
+	$(nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES) \
+	$(png_fix_itxt_SOURCES) $(pngcp_SOURCES) $(pngfix_SOURCES) \
+	$(pngimage_SOURCES) $(pngstest_SOURCES) $(pngtest_SOURCES) \
+	$(pngunknown_SOURCES) $(pngvalid_SOURCES) $(timepng_SOURCES)
+DIST_SOURCES =  \
+	$(am__libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES_DIST) \
+	$(png_fix_itxt_SOURCES) $(pngcp_SOURCES) $(pngfix_SOURCES) \
+	$(pngimage_SOURCES) $(pngstest_SOURCES) $(pngtest_SOURCES) \
+	$(pngunknown_SOURCES) $(pngvalid_SOURCES) $(timepng_SOURCES)
+am__can_run_installinfo = \
+  case $$AM_UPDATE_INFO_DIR in \
+    n|no|NO) false;; \
+    *) (install-info --version) >/dev/null 2>&1;; \
+  esac
+man3dir = $(mandir)/man3
+man5dir = $(mandir)/man5
+NROFF = nroff
+MANS = $(dist_man_MANS)
+DATA = $(pkgconfig_DATA)
+HEADERS = $(nodist_pkginclude_HEADERS) $(pkginclude_HEADERS)
+am__tagged_files = $(HEADERS) $(SOURCES) $(TAGS_FILES) \
+	$(LISP)config.h.in
+# Read a list of newline-separated strings from the standard input,
+# and print each of them once, without duplicates.  Input order is
+# *not* preserved.
+am__uniquify_input = $(AWK) '\
+  BEGIN { nonempty = 0; } \
+  { items[$$0] = 1; nonempty = 1; } \
+  END { if (nonempty) { for (i in items) print i; }; } \
+'
+# Make sure the list of sources is unique.  This is necessary because,
+# e.g., the same source file might be shared among _SOURCES variables
+# for different programs/libraries.
+am__define_uniq_tagged_files = \
+  list='$(am__tagged_files)'; \
+  unique=`for i in $$list; do \
+    if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
+  done | $(am__uniquify_input)`
+ETAGS = etags
+CTAGS = ctags
+CSCOPE = cscope
+AM_RECURSIVE_TARGETS = cscope check recheck
+am__tty_colors_dummy = \
+  mgn= red= grn= lgn= blu= brg= std=; \
+  am__color_tests=no
+am__tty_colors = { \
+  $(am__tty_colors_dummy); \
+  if test "X$(AM_COLOR_TESTS)" = Xno; then \
+    am__color_tests=no; \
+  elif test "X$(AM_COLOR_TESTS)" = Xalways; then \
+    am__color_tests=yes; \
+  elif test "X$$TERM" != Xdumb && { test -t 1; } 2>/dev/null; then \
+    am__color_tests=yes; \
+  fi; \
+  if test $$am__color_tests = yes; then \
+    red=''; \
+    grn=''; \
+    lgn=''; \
+    blu=''; \
+    mgn=''; \
+    brg=''; \
+    std=''; \
+  fi; \
+}
+am__recheck_rx = ^[ 	]*:recheck:[ 	]*
+am__global_test_result_rx = ^[ 	]*:global-test-result:[ 	]*
+am__copy_in_global_log_rx = ^[ 	]*:copy-in-global-log:[ 	]*
+# A command that, given a newline-separated list of test names on the
+# standard input, print the name of the tests that are to be re-run
+# upon "make recheck".
+am__list_recheck_tests = $(AWK) '{ \
+  recheck = 1; \
+  while ((rc = (getline line < ($$0 ".trs"))) != 0) \
+    { \
+      if (rc < 0) \
+        { \
+          if ((getline line2 < ($$0 ".log")) < 0) \
+	    recheck = 0; \
+          break; \
+        } \
+      else if (line ~ /$(am__recheck_rx)[nN][Oo]/) \
+        { \
+          recheck = 0; \
+          break; \
+        } \
+      else if (line ~ /$(am__recheck_rx)[yY][eE][sS]/) \
+        { \
+          break; \
+        } \
+    }; \
+  if (recheck) \
+    print $$0; \
+  close ($$0 ".trs"); \
+  close ($$0 ".log"); \
+}'
+# A command that, given a newline-separated list of test names on the
+# standard input, create the global log from their .trs and .log files.
+am__create_global_log = $(AWK) ' \
+function fatal(msg) \
+{ \
+  print "fatal: making $@: " msg | "cat >&2"; \
+  exit 1; \
+} \
+function rst_section(header) \
+{ \
+  print header; \
+  len = length(header); \
+  for (i = 1; i <= len; i = i + 1) \
+    printf "="; \
+  printf "\n\n"; \
+} \
+{ \
+  copy_in_global_log = 1; \
+  global_test_result = "RUN"; \
+  while ((rc = (getline line < ($$0 ".trs"))) != 0) \
+    { \
+      if (rc < 0) \
+         fatal("failed to read from " $$0 ".trs"); \
+      if (line ~ /$(am__global_test_result_rx)/) \
+        { \
+          sub("$(am__global_test_result_rx)", "", line); \
+          sub("[ 	]*$$", "", line); \
+          global_test_result = line; \
+        } \
+      else if (line ~ /$(am__copy_in_global_log_rx)[nN][oO]/) \
+        copy_in_global_log = 0; \
+    }; \
+  if (copy_in_global_log) \
+    { \
+      rst_section(global_test_result ": " $$0); \
+      while ((rc = (getline line < ($$0 ".log"))) != 0) \
+      { \
+        if (rc < 0) \
+          fatal("failed to read from " $$0 ".log"); \
+        print line; \
+      }; \
+      printf "\n"; \
+    }; \
+  close ($$0 ".trs"); \
+  close ($$0 ".log"); \
+}'
+# Restructured Text title.
+am__rst_title = { sed 's/.*/   &   /;h;s/./=/g;p;x;s/ *$$//;p;g' && echo; }
+# Solaris 10 'make', and several other traditional 'make' implementations,
+# pass "-e" to $(SHELL), and POSIX 2008 even requires this.  Work around it
+# by disabling -e (using the XSI extension "set +e") if it's set.
+am__sh_e_setup = case $$- in *e*) set +e;; esac
+# Default flags passed to test drivers.
+am__common_driver_flags = \
+  --color-tests "$$am__color_tests" \
+  --enable-hard-errors "$$am__enable_hard_errors" \
+  --expect-failure "$$am__expect_failure"
+# To be inserted before the command running the test.  Creates the
+# directory for the log if needed.  Stores in $dir the directory
+# containing $f, in $tst the test, in $log the log.  Executes the
+# developer- defined test setup AM_TESTS_ENVIRONMENT (if any), and
+# passes TESTS_ENVIRONMENT.  Set up options for the wrapper that
+# will run the test scripts (or their associated LOG_COMPILER, if
+# thy have one).
+am__check_pre = \
+$(am__sh_e_setup);					\
+$(am__vpath_adj_setup) $(am__vpath_adj)			\
+$(am__tty_colors);					\
+srcdir=$(srcdir); export srcdir;			\
+case "$@" in						\
+  */*) am__odir=`echo "./$@" | sed 's|/[^/]*$$||'`;;	\
+    *) am__odir=.;; 					\
+esac;							\
+test "x$$am__odir" = x"." || test -d "$$am__odir" 	\
+  || $(MKDIR_P) "$$am__odir" || exit $$?;		\
+if test -f "./$$f"; then dir=./;			\
+elif test -f "$$f"; then dir=;				\
+else dir="$(srcdir)/"; fi;				\
+tst=$$dir$$f; log='$@'; 				\
+if test -n '$(DISABLE_HARD_ERRORS)'; then		\
+  am__enable_hard_errors=no; 				\
+else							\
+  am__enable_hard_errors=yes; 				\
+fi; 							\
+case " $(XFAIL_TESTS) " in				\
+  *[\ \	]$$f[\ \	]* | *[\ \	]$$dir$$f[\ \	]*) \
+    am__expect_failure=yes;;				\
+  *)							\
+    am__expect_failure=no;;				\
+esac; 							\
+$(AM_TESTS_ENVIRONMENT) $(TESTS_ENVIRONMENT)
+# A shell command to get the names of the tests scripts with any registered
+# extension removed (i.e., equivalently, the names of the test logs, with
+# the '.log' extension removed).  The result is saved in the shell variable
+# '$bases'.  This honors runtime overriding of TESTS and TEST_LOGS.  Sadly,
+# we cannot use something simpler, involving e.g., "$(TEST_LOGS:.log=)",
+# since that might cause problem with VPATH rewrites for suffix-less tests.
+# See also 'test-harness-vpath-rewrite.sh' and 'test-trs-basic.sh'.
+am__set_TESTS_bases = \
+  bases='$(TEST_LOGS)'; \
+  bases=`for i in $$bases; do echo $$i; done | sed 's/\.log$$//'`; \
+  bases=`echo $$bases`
+RECHECK_LOGS = $(TEST_LOGS)
+TEST_SUITE_LOG = test-suite.log
+TEST_EXTENSIONS = @EXEEXT@ .test
+LOG_DRIVER = $(SHELL) $(top_srcdir)/test-driver
+LOG_COMPILE = $(LOG_COMPILER) $(AM_LOG_FLAGS) $(LOG_FLAGS)
+am__set_b = \
+  case '$@' in \
+    */*) \
+      case '$*' in \
+        */*) b='$*';; \
+          *) b=`echo '$@' | sed 's/\.log$$//'`; \
+       esac;; \
+    *) \
+      b='$*';; \
+  esac
+am__test_logs1 = $(TESTS:=.log)
+am__test_logs2 = $(am__test_logs1:@EXEEXT@.log=.log)
+TEST_LOGS = $(am__test_logs2:.test.log=.log)
+TEST_LOG_DRIVER = $(SHELL) $(top_srcdir)/test-driver
+TEST_LOG_COMPILE = $(TEST_LOG_COMPILER) $(AM_TEST_LOG_FLAGS) \
+	$(TEST_LOG_FLAGS)
+am__DIST_COMMON = $(dist_man_MANS) $(srcdir)/Makefile.in \
+	$(srcdir)/config.h.in $(srcdir)/libpng-config.in \
+	$(srcdir)/libpng.pc.in AUTHORS INSTALL README TODO compile \
+	config.guess config.sub depcomp install-sh ltmain.sh missing \
+	test-driver
+DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
+distdir = $(PACKAGE)-$(VERSION)
+top_distdir = $(distdir)
+am__remove_distdir = \
+  if test -d "$(distdir)"; then \
+    find "$(distdir)" -type d ! -perm -200 -exec chmod u+w {} ';' \
+      && rm -rf "$(distdir)" \
+      || { sleep 5 && rm -rf "$(distdir)"; }; \
+  else :; fi
+am__post_remove_distdir = $(am__remove_distdir)
+DIST_ARCHIVES = $(distdir).tar.gz $(distdir).tar.xz
+GZIP_ENV = --best
+DIST_TARGETS = dist-xz dist-gzip
+distuninstallcheck_listfiles = find . -type f -print
+am__distuninstallcheck_listfiles = $(distuninstallcheck_listfiles) \
+  | sed 's|^\./|$(prefix)/|' | grep -v '$(infodir)/dir$$'
+distcleancheck_listfiles = find . -type f -print
+
+#distribute headers in /usr/include/libpng/*
+pkgincludedir = $(includedir)/$(PNGLIB_BASENAME)
+ACLOCAL = @ACLOCAL@
+AMTAR = @AMTAR@
+AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+AR = @AR@
+AS = @AS@
+AUTOCONF = @AUTOCONF@
+AUTOHEADER = @AUTOHEADER@
+AUTOMAKE = @AUTOMAKE@
+AWK = @AWK@
+CC = @CC@
+CCAS = @CCAS@
+CCASDEPMODE = @CCASDEPMODE@
+CCASFLAGS = @CCASFLAGS@
+CCDEPMODE = @CCDEPMODE@
+CFLAGS = @CFLAGS@
+CPP = @CPP@
+CPPFLAGS = @CPPFLAGS@
+CYGPATH_W = @CYGPATH_W@
+DEFS = @DEFS@
+DEPDIR = @DEPDIR@
+
+# DFNCPP is normally just CPP - the C preprocessor - but on Solaris and maybe
+# other operating systems (NeXT?) the C preprocessor selected by configure
+# checks input tokens for validity - effectively it performs part of the ANSI-C
+# parsing - and therefore fails with the .df files.  configure.ac has special
+# checks for this and sets DFNCPP appropriately.
+DFNCPP = @DFNCPP@
+DLLTOOL = @DLLTOOL@
+DSYMUTIL = @DSYMUTIL@
+DUMPBIN = @DUMPBIN@
+ECHO_C = @ECHO_C@
+ECHO_N = @ECHO_N@
+ECHO_T = @ECHO_T@
+EGREP = @EGREP@
+EXEEXT = @EXEEXT@
+FGREP = @FGREP@
+GREP = @GREP@
+INSTALL = @INSTALL@
+INSTALL_DATA = @INSTALL_DATA@
+INSTALL_PROGRAM = @INSTALL_PROGRAM@
+INSTALL_SCRIPT = @INSTALL_SCRIPT@
+INSTALL_STRIP_PROGRAM = @INSTALL_STRIP_PROGRAM@
+LD = @LD@
+LDFLAGS = @LDFLAGS@
+LIBOBJS = @LIBOBJS@
+LIBS = @LIBS@
+LIBTOOL = @LIBTOOL@
+LIPO = @LIPO@
+LN_S = @LN_S@
+LTLIBOBJS = @LTLIBOBJS@
+LT_SYS_LIBRARY_PATH = @LT_SYS_LIBRARY_PATH@
+MAINT = @MAINT@
+MAKEINFO = @MAKEINFO@
+MANIFEST_TOOL = @MANIFEST_TOOL@
+MKDIR_P = @MKDIR_P@
+NM = @NM@
+NMEDIT = @NMEDIT@
+OBJDUMP = @OBJDUMP@
+OBJEXT = @OBJEXT@
+OTOOL = @OTOOL@
+OTOOL64 = @OTOOL64@
+PACKAGE = @PACKAGE@
+PACKAGE_BUGREPORT = @PACKAGE_BUGREPORT@
+PACKAGE_NAME = @PACKAGE_NAME@
+PACKAGE_STRING = @PACKAGE_STRING@
+PACKAGE_TARNAME = @PACKAGE_TARNAME@
+PACKAGE_URL = @PACKAGE_URL@
+PACKAGE_VERSION = @PACKAGE_VERSION@
+PATH_SEPARATOR = @PATH_SEPARATOR@
+PNGLIB_MAJOR = @PNGLIB_MAJOR@
+PNGLIB_MINOR = @PNGLIB_MINOR@
+PNGLIB_RELEASE = @PNGLIB_RELEASE@
+PNGLIB_VERSION = @PNGLIB_VERSION@
+
+# PNG_COPTS give extra options for the C compiler to be used on all compilation
+# steps (unless targe_CFLAGS is specified; that will take precedence over
+# AM_CFLAGS)
+PNG_COPTS = @PNG_COPTS@
+PNG_PREFIX = @PNG_PREFIX@
+POW_LIB = @POW_LIB@
+RANLIB = @RANLIB@
+SED = @SED@
+SET_MAKE = @SET_MAKE@
+SHELL = @SHELL@
+STRIP = @STRIP@
+SYMBOL_PREFIX = @SYMBOL_PREFIX@
+VERSION = @VERSION@
+abs_builddir = @abs_builddir@
+abs_srcdir = @abs_srcdir@
+abs_top_builddir = @abs_top_builddir@
+abs_top_srcdir = @abs_top_srcdir@
+ac_ct_AR = @ac_ct_AR@
+ac_ct_CC = @ac_ct_CC@
+ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+am__include = @am__include@
+am__leading_dot = @am__leading_dot@
+am__quote = @am__quote@
+am__tar = @am__tar@
+am__untar = @am__untar@
+
+# generate the -config scripts if required
+binconfigs = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
+bindir = @bindir@
+build = @build@
+build_alias = @build_alias@
+build_cpu = @build_cpu@
+build_os = @build_os@
+build_vendor = @build_vendor@
+builddir = @builddir@
+datadir = @datadir@
+datarootdir = @datarootdir@
+docdir = @docdir@
+dvidir = @dvidir@
+exec_prefix = @exec_prefix@
+host = @host@
+host_alias = @host_alias@
+host_cpu = @host_cpu@
+host_os = @host_os@
+host_vendor = @host_vendor@
+htmldir = @htmldir@
+includedir = @includedir@
+infodir = @infodir@
+install_sh = @install_sh@
+libdir = @libdir@
+libexecdir = @libexecdir@
+localedir = @localedir@
+localstatedir = @localstatedir@
+mandir = @mandir@
+mkdir_p = @mkdir_p@
+oldincludedir = @oldincludedir@
+pdfdir = @pdfdir@
+
+# pkg-config stuff, note that libpng.pc is always required in order
+# to get the correct library
+pkgconfigdir = @pkgconfigdir@
+prefix = @prefix@
+program_transform_name = @program_transform_name@
+psdir = @psdir@
+sbindir = @sbindir@
+sharedstatedir = @sharedstatedir@
+srcdir = @srcdir@
+sysconfdir = @sysconfdir@
+target_alias = @target_alias@
+top_build_prefix = @top_build_prefix@
+top_builddir = @top_builddir@
+top_srcdir = @top_srcdir@
+PNGLIB_BASENAME = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+ACLOCAL_AMFLAGS = -I scripts
+
+# This ensures that pnglibconf.h gets built at the start of 'make all' or
+# 'make check', but it does not add dependencies to the individual programs,
+# this is done below.
+#
+# IMPORTANT: always add the object modules of new programs to the list below
+# because otherwise the sequence 'configure; make new-program' will *sometimes*
+# result in the installed (system) pnglibconf.h being used and the result is
+# always wrong and always very confusing.
+BUILT_SOURCES = pnglibconf.h
+pngtest_SOURCES = pngtest.c
+pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngvalid_SOURCES = contrib/libtests/pngvalid.c
+pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngstest_SOURCES = contrib/libtests/pngstest.c
+pngstest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngunknown_SOURCES = contrib/libtests/pngunknown.c
+pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngimage_SOURCES = contrib/libtests/pngimage.c
+pngimage_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+timepng_SOURCES = contrib/libtests/timepng.c
+timepng_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngfix_SOURCES = contrib/tools/pngfix.c
+pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c
+pngcp_SOURCES = contrib/tools/pngcp.c
+pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+# Generally these are single line shell scripts to run a test with a particular
+# set of parameters:
+TESTS = \
+   tests/pngtest\
+   tests/pngtest-badpngs\
+   tests/pngvalid-gamma-16-to-8 tests/pngvalid-gamma-alpha-mode\
+   tests/pngvalid-gamma-background tests/pngvalid-gamma-expand16-alpha-mode\
+   tests/pngvalid-gamma-expand16-background\
+   tests/pngvalid-gamma-expand16-transform tests/pngvalid-gamma-sbit\
+   tests/pngvalid-gamma-threshold tests/pngvalid-gamma-transform\
+   tests/pngvalid-progressive-size\
+   tests/pngvalid-progressive-interlace-standard\
+   tests/pngvalid-transform\
+   tests/pngvalid-progressive-standard tests/pngvalid-standard\
+   tests/pngstest-1.8 tests/pngstest-1.8-alpha tests/pngstest-linear\
+   tests/pngstest-linear-alpha tests/pngstest-none tests/pngstest-none-alpha\
+   tests/pngstest-sRGB tests/pngstest-sRGB-alpha tests/pngunknown-IDAT\
+   tests/pngunknown-discard tests/pngunknown-if-safe tests/pngunknown-sAPI\
+   tests/pngunknown-sTER tests/pngunknown-save tests/pngunknown-vpAg\
+   tests/pngimage-quick tests/pngimage-full
+
+
+# man pages
+dist_man_MANS = libpng.3 libpngpf.3 png.5
+EXTRA_SCRIPTS = libpng-config libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
+bin_SCRIPTS = @binconfigs@
+
+# rules to build libpng, only build the old library on request
+lib_LTLIBRARIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+# EXTRA_LTLIBRARIES= libpng.la
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c \
+	pngget.c pngmem.c pngpread.c pngread.c pngrio.c pngrtran.c \
+	pngrutil.c pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c \
+	pngwutil.c png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h \
+	pngstruct.h pngusr.dfa $(am__append_2) $(am__append_3) \
+	$(am__append_4) $(am__append_5)
+nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined \
+	-export-dynamic -version-number \
+	@PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0 \
+	$(am__append_6) $(am__append_7) $(am__append_8)
+@HAVE_LD_VERSION_SCRIPT_FALSE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.sym
+@HAVE_LD_VERSION_SCRIPT_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.vers
+pkginclude_HEADERS = png.h pngconf.h
+nodist_pkginclude_HEADERS = pnglibconf.h
+pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc
+
+# Extra source distribution files, '${srcdir}' is used below to stop build files
+# from those directories being included.  This only works if the configure is
+# not done in the source directory!
+EXTRA_DIST = \
+	ANNOUNCE AUTHORS CHANGES INSTALL LICENSE README TODO TRADEMARK \
+	pngtest.png pngbar.png pngnow.png pngbar.jpg autogen.sh \
+	${srcdir}/contrib ${srcdir}/projects ${srcdir}/scripts \
+	$(TESTS) $(XFAIL_TESTS) tests/pngstest \
+	CMakeLists.txt example.c libpng-manual.txt
+
+SCRIPT_CLEANFILES = scripts/*.out scripts/*.chk
+CLEANFILES = *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
+	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
+	check.new pnglibconf.h pngprefix.h symbols.new pngtest-log.txt \
+	pnglibconf.out pnglibconf.c pnglibconf.pre pnglibconf.dfn \
+	$(SCRIPT_CLEANFILES)
+
+MAINTAINERCLEANFILES = Makefile.in aclocal.m4 config.guess config.h.in \
+config.sub configure depcomp install-sh ltmain.sh missing
+
+AM_CFLAGS = ${PNG_COPTS}
+SUFFIXES = .chk .out
+
+# We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
+# be built with PNG_USE_READ_MACROS; this prevents the read macros from
+# interfering with the symbol file format.
+SYMBOL_CFLAGS = -DPNGLIB_LIBNAME='PNG@PNGLIB_MAJOR@@PNGLIB_MINOR@_0' \
+	-DPNGLIB_VERSION='@PNGLIB_VERSION@' \
+	-DSYMBOL_PREFIX='$(SYMBOL_PREFIX)' -DPNG_NO_USE_READ_MACROS \
+	-DPNG_BUILDING_SYMBOL_TABLE $(am__append_9)
+
+# EXT_LIST is a list of the possibly library directory extensions, this exists
+# because we can't find a good way of discovering the file extensions that are
+# actually installed on a given system, so instead we check for every extension
+# we have seen.
+EXT_LIST = a dll.a so so.@PNGLIB_MAJOR@@PNGLIB_MINOR@.@PNGLIB_RELEASE@ la sl dylib
+all: $(BUILT_SOURCES) config.h
+	$(MAKE) $(AM_MAKEFLAGS) all-am
+
+.SUFFIXES:
+.SUFFIXES: .chk .out .S .c .lo .log .o .obj .test .test$(EXEEXT) .trs
+am--refresh: Makefile
+	@:
+$(srcdir)/Makefile.in: @MAINTAINER_MODE_TRUE@ $(srcdir)/Makefile.am  $(am__configure_deps)
+	@for dep in $?; do \
+	  case '$(am__configure_deps)' in \
+	    *$$dep*) \
+	      echo ' cd $(srcdir) && $(AUTOMAKE) --foreign'; \
+	      $(am__cd) $(srcdir) && $(AUTOMAKE) --foreign \
+		&& exit 0; \
+	      exit 1;; \
+	  esac; \
+	done; \
+	echo ' cd $(top_srcdir) && $(AUTOMAKE) --foreign Makefile'; \
+	$(am__cd) $(top_srcdir) && \
+	  $(AUTOMAKE) --foreign Makefile
+Makefile: $(srcdir)/Makefile.in $(top_builddir)/config.status
+	@case '$?' in \
+	  *config.status*) \
+	    echo ' $(SHELL) ./config.status'; \
+	    $(SHELL) ./config.status;; \
+	  *) \
+	    echo ' cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__maybe_remake_depfiles)'; \
+	    cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__maybe_remake_depfiles);; \
+	esac;
+
+$(top_builddir)/config.status: $(top_srcdir)/configure $(CONFIG_STATUS_DEPENDENCIES)
+	$(SHELL) ./config.status --recheck
+
+$(top_srcdir)/configure: @MAINTAINER_MODE_TRUE@ $(am__configure_deps)
+	$(am__cd) $(srcdir) && $(AUTOCONF)
+$(ACLOCAL_M4): @MAINTAINER_MODE_TRUE@ $(am__aclocal_m4_deps)
+	$(am__cd) $(srcdir) && $(ACLOCAL) $(ACLOCAL_AMFLAGS)
+$(am__aclocal_m4_deps):
+
+config.h: stamp-h1
+	@test -f $@ || rm -f stamp-h1
+	@test -f $@ || $(MAKE) $(AM_MAKEFLAGS) stamp-h1
+
+stamp-h1: $(srcdir)/config.h.in $(top_builddir)/config.status
+	@rm -f stamp-h1
+	cd $(top_builddir) && $(SHELL) ./config.status config.h
+$(srcdir)/config.h.in: @MAINTAINER_MODE_TRUE@ $(am__configure_deps) 
+	($(am__cd) $(top_srcdir) && $(AUTOHEADER))
+	rm -f stamp-h1
+	touch $@
+
+distclean-hdr:
+	-rm -f config.h stamp-h1
+libpng.pc: $(top_builddir)/config.status $(srcdir)/libpng.pc.in
+	cd $(top_builddir) && $(SHELL) ./config.status $@
+libpng-config: $(top_builddir)/config.status $(srcdir)/libpng-config.in
+	cd $(top_builddir) && $(SHELL) ./config.status $@
+install-binPROGRAMS: $(bin_PROGRAMS)
+	@$(NORMAL_INSTALL)
+	@list='$(bin_PROGRAMS)'; test -n "$(bindir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(bindir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(bindir)" || exit 1; \
+	fi; \
+	for p in $$list; do echo "$$p $$p"; done | \
+	sed 's/$(EXEEXT)$$//' | \
+	while read p p1; do if test -f $$p \
+	 || test -f $$p1 \
+	  ; then echo "$$p"; echo "$$p"; else :; fi; \
+	done | \
+	sed -e 'p;s,.*/,,;n;h' \
+	    -e 's|.*|.|' \
+	    -e 'p;x;s,.*/,,;s/$(EXEEXT)$$//;$(transform);s/$$/$(EXEEXT)/' | \
+	sed 'N;N;N;s,\n, ,g' | \
+	$(AWK) 'BEGIN { files["."] = ""; dirs["."] = 1 } \
+	  { d=$$3; if (dirs[d] != 1) { print "d", d; dirs[d] = 1 } \
+	    if ($$2 == $$4) files[d] = files[d] " " $$1; \
+	    else { print "f", $$3 "/" $$4, $$1; } } \
+	  END { for (d in files) print "f", d, files[d] }' | \
+	while read type dir files; do \
+	    if test "$$dir" = .; then dir=; else dir=/$$dir; fi; \
+	    test -z "$$files" || { \
+	    echo " $(INSTALL_PROGRAM_ENV) $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=install $(INSTALL_PROGRAM) $$files '$(DESTDIR)$(bindir)$$dir'"; \
+	    $(INSTALL_PROGRAM_ENV) $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=install $(INSTALL_PROGRAM) $$files "$(DESTDIR)$(bindir)$$dir" || exit $$?; \
+	    } \
+	; done
+
+uninstall-binPROGRAMS:
+	@$(NORMAL_UNINSTALL)
+	@list='$(bin_PROGRAMS)'; test -n "$(bindir)" || list=; \
+	files=`for p in $$list; do echo "$$p"; done | \
+	  sed -e 'h;s,^.*/,,;s/$(EXEEXT)$$//;$(transform)' \
+	      -e 's/$$/$(EXEEXT)/' \
+	`; \
+	test -n "$$list" || exit 0; \
+	echo " ( cd '$(DESTDIR)$(bindir)' && rm -f" $$files ")"; \
+	cd "$(DESTDIR)$(bindir)" && rm -f $$files
+
+clean-binPROGRAMS:
+	@list='$(bin_PROGRAMS)'; test -n "$$list" || exit 0; \
+	echo " rm -f" $$list; \
+	rm -f $$list || exit $$?; \
+	test -n "$(EXEEXT)" || exit 0; \
+	list=`for p in $$list; do echo "$$p"; done | sed 's/$(EXEEXT)$$//'`; \
+	echo " rm -f" $$list; \
+	rm -f $$list
+
+clean-checkPROGRAMS:
+	@list='$(check_PROGRAMS)'; test -n "$$list" || exit 0; \
+	echo " rm -f" $$list; \
+	rm -f $$list || exit $$?; \
+	test -n "$(EXEEXT)" || exit 0; \
+	list=`for p in $$list; do echo "$$p"; done | sed 's/$(EXEEXT)$$//'`; \
+	echo " rm -f" $$list; \
+	rm -f $$list
+
+install-libLTLIBRARIES: $(lib_LTLIBRARIES)
+	@$(NORMAL_INSTALL)
+	@list='$(lib_LTLIBRARIES)'; test -n "$(libdir)" || list=; \
+	list2=; for p in $$list; do \
+	  if test -f $$p; then \
+	    list2="$$list2 $$p"; \
+	  else :; fi; \
+	done; \
+	test -z "$$list2" || { \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(libdir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(libdir)" || exit 1; \
+	  echo " $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=install $(INSTALL) $(INSTALL_STRIP_FLAG) $$list2 '$(DESTDIR)$(libdir)'"; \
+	  $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=install $(INSTALL) $(INSTALL_STRIP_FLAG) $$list2 "$(DESTDIR)$(libdir)"; \
+	}
+
+uninstall-libLTLIBRARIES:
+	@$(NORMAL_UNINSTALL)
+	@list='$(lib_LTLIBRARIES)'; test -n "$(libdir)" || list=; \
+	for p in $$list; do \
+	  $(am__strip_dir) \
+	  echo " $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=uninstall rm -f '$(DESTDIR)$(libdir)/$$f'"; \
+	  $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=uninstall rm -f "$(DESTDIR)$(libdir)/$$f"; \
+	done
+
+clean-libLTLIBRARIES:
+	-test -z "$(lib_LTLIBRARIES)" || rm -f $(lib_LTLIBRARIES)
+	@list='$(lib_LTLIBRARIES)'; \
+	locs=`for p in $$list; do echo $$p; done | \
+	      sed 's|^[^/]*$$|.|; s|/[^/]*$$||; s|$$|/so_locations|' | \
+	      sort -u`; \
+	test -z "$$locs" || { \
+	  echo rm -f $${locs}; \
+	  rm -f $${locs}; \
+	}
+arm/$(am__dirstamp):
+	@$(MKDIR_P) arm
+	@: > arm/$(am__dirstamp)
+arm/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) arm/$(DEPDIR)
+	@: > arm/$(DEPDIR)/$(am__dirstamp)
+arm/arm_init.lo: arm/$(am__dirstamp) arm/$(DEPDIR)/$(am__dirstamp)
+arm/filter_neon.lo: arm/$(am__dirstamp) arm/$(DEPDIR)/$(am__dirstamp)
+arm/filter_neon_intrinsics.lo: arm/$(am__dirstamp) \
+	arm/$(DEPDIR)/$(am__dirstamp)
+arm/palette_neon_intrinsics.lo: arm/$(am__dirstamp) \
+	arm/$(DEPDIR)/$(am__dirstamp)
+mips/$(am__dirstamp):
+	@$(MKDIR_P) mips
+	@: > mips/$(am__dirstamp)
+mips/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) mips/$(DEPDIR)
+	@: > mips/$(DEPDIR)/$(am__dirstamp)
+mips/mips_init.lo: mips/$(am__dirstamp) mips/$(DEPDIR)/$(am__dirstamp)
+mips/filter_msa_intrinsics.lo: mips/$(am__dirstamp) \
+	mips/$(DEPDIR)/$(am__dirstamp)
+intel/$(am__dirstamp):
+	@$(MKDIR_P) intel
+	@: > intel/$(am__dirstamp)
+intel/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) intel/$(DEPDIR)
+	@: > intel/$(DEPDIR)/$(am__dirstamp)
+intel/intel_init.lo: intel/$(am__dirstamp) \
+	intel/$(DEPDIR)/$(am__dirstamp)
+intel/filter_sse2_intrinsics.lo: intel/$(am__dirstamp) \
+	intel/$(DEPDIR)/$(am__dirstamp)
+powerpc/$(am__dirstamp):
+	@$(MKDIR_P) powerpc
+	@: > powerpc/$(am__dirstamp)
+powerpc/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) powerpc/$(DEPDIR)
+	@: > powerpc/$(DEPDIR)/$(am__dirstamp)
+powerpc/powerpc_init.lo: powerpc/$(am__dirstamp) \
+	powerpc/$(DEPDIR)/$(am__dirstamp)
+powerpc/filter_vsx_intrinsics.lo: powerpc/$(am__dirstamp) \
+	powerpc/$(DEPDIR)/$(am__dirstamp)
+
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la: $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES) $(EXTRA_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES) 
+	$(AM_V_CCLD)$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LINK) -rpath $(libdir) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD) $(LIBS)
+contrib/tools/$(am__dirstamp):
+	@$(MKDIR_P) contrib/tools
+	@: > contrib/tools/$(am__dirstamp)
+contrib/tools/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) contrib/tools/$(DEPDIR)
+	@: > contrib/tools/$(DEPDIR)/$(am__dirstamp)
+contrib/tools/png-fix-itxt.$(OBJEXT): contrib/tools/$(am__dirstamp) \
+	contrib/tools/$(DEPDIR)/$(am__dirstamp)
+
+png-fix-itxt$(EXEEXT): $(png_fix_itxt_OBJECTS) $(png_fix_itxt_DEPENDENCIES) $(EXTRA_png_fix_itxt_DEPENDENCIES) 
+	@rm -f png-fix-itxt$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(png_fix_itxt_OBJECTS) $(png_fix_itxt_LDADD) $(LIBS)
+contrib/tools/pngcp.$(OBJEXT): contrib/tools/$(am__dirstamp) \
+	contrib/tools/$(DEPDIR)/$(am__dirstamp)
+
+pngcp$(EXEEXT): $(pngcp_OBJECTS) $(pngcp_DEPENDENCIES) $(EXTRA_pngcp_DEPENDENCIES) 
+	@rm -f pngcp$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngcp_OBJECTS) $(pngcp_LDADD) $(LIBS)
+contrib/tools/pngfix.$(OBJEXT): contrib/tools/$(am__dirstamp) \
+	contrib/tools/$(DEPDIR)/$(am__dirstamp)
+
+pngfix$(EXEEXT): $(pngfix_OBJECTS) $(pngfix_DEPENDENCIES) $(EXTRA_pngfix_DEPENDENCIES) 
+	@rm -f pngfix$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngfix_OBJECTS) $(pngfix_LDADD) $(LIBS)
+contrib/libtests/$(am__dirstamp):
+	@$(MKDIR_P) contrib/libtests
+	@: > contrib/libtests/$(am__dirstamp)
+contrib/libtests/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) contrib/libtests/$(DEPDIR)
+	@: > contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+contrib/libtests/pngimage.$(OBJEXT): contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+pngimage$(EXEEXT): $(pngimage_OBJECTS) $(pngimage_DEPENDENCIES) $(EXTRA_pngimage_DEPENDENCIES) 
+	@rm -f pngimage$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngimage_OBJECTS) $(pngimage_LDADD) $(LIBS)
+contrib/libtests/pngstest.$(OBJEXT): contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+pngstest$(EXEEXT): $(pngstest_OBJECTS) $(pngstest_DEPENDENCIES) $(EXTRA_pngstest_DEPENDENCIES) 
+	@rm -f pngstest$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngstest_OBJECTS) $(pngstest_LDADD) $(LIBS)
+
+pngtest$(EXEEXT): $(pngtest_OBJECTS) $(pngtest_DEPENDENCIES) $(EXTRA_pngtest_DEPENDENCIES) 
+	@rm -f pngtest$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngtest_OBJECTS) $(pngtest_LDADD) $(LIBS)
+contrib/libtests/pngunknown.$(OBJEXT):  \
+	contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+pngunknown$(EXEEXT): $(pngunknown_OBJECTS) $(pngunknown_DEPENDENCIES) $(EXTRA_pngunknown_DEPENDENCIES) 
+	@rm -f pngunknown$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngunknown_OBJECTS) $(pngunknown_LDADD) $(LIBS)
+contrib/libtests/pngvalid.$(OBJEXT): contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+pngvalid$(EXEEXT): $(pngvalid_OBJECTS) $(pngvalid_DEPENDENCIES) $(EXTRA_pngvalid_DEPENDENCIES) 
+	@rm -f pngvalid$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngvalid_OBJECTS) $(pngvalid_LDADD) $(LIBS)
+contrib/libtests/timepng.$(OBJEXT): contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+timepng$(EXEEXT): $(timepng_OBJECTS) $(timepng_DEPENDENCIES) $(EXTRA_timepng_DEPENDENCIES) 
+	@rm -f timepng$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(timepng_OBJECTS) $(timepng_LDADD) $(LIBS)
+install-binSCRIPTS: $(bin_SCRIPTS)
+	@$(NORMAL_INSTALL)
+	@list='$(bin_SCRIPTS)'; test -n "$(bindir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(bindir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(bindir)" || exit 1; \
+	fi; \
+	for p in $$list; do \
+	  if test -f "$$p"; then d=; else d="$(srcdir)/"; fi; \
+	  if test -f "$$d$$p"; then echo "$$d$$p"; echo "$$p"; else :; fi; \
+	done | \
+	sed -e 'p;s,.*/,,;n' \
+	    -e 'h;s|.*|.|' \
+	    -e 'p;x;s,.*/,,;$(transform)' | sed 'N;N;N;s,\n, ,g' | \
+	$(AWK) 'BEGIN { files["."] = ""; dirs["."] = 1; } \
+	  { d=$$3; if (dirs[d] != 1) { print "d", d; dirs[d] = 1 } \
+	    if ($$2 == $$4) { files[d] = files[d] " " $$1; \
+	      if (++n[d] == $(am__install_max)) { \
+		print "f", d, files[d]; n[d] = 0; files[d] = "" } } \
+	    else { print "f", d "/" $$4, $$1 } } \
+	  END { for (d in files) print "f", d, files[d] }' | \
+	while read type dir files; do \
+	     if test "$$dir" = .; then dir=; else dir=/$$dir; fi; \
+	     test -z "$$files" || { \
+	       echo " $(INSTALL_SCRIPT) $$files '$(DESTDIR)$(bindir)$$dir'"; \
+	       $(INSTALL_SCRIPT) $$files "$(DESTDIR)$(bindir)$$dir" || exit $$?; \
+	     } \
+	; done
+
+uninstall-binSCRIPTS:
+	@$(NORMAL_UNINSTALL)
+	@list='$(bin_SCRIPTS)'; test -n "$(bindir)" || exit 0; \
+	files=`for p in $$list; do echo "$$p"; done | \
+	       sed -e 's,.*/,,;$(transform)'`; \
+	dir='$(DESTDIR)$(bindir)'; $(am__uninstall_files_from_dir)
+
+mostlyclean-compile:
+	-rm -f *.$(OBJEXT)
+	-rm -f arm/*.$(OBJEXT)
+	-rm -f arm/*.lo
+	-rm -f contrib/libtests/*.$(OBJEXT)
+	-rm -f contrib/tools/*.$(OBJEXT)
+	-rm -f intel/*.$(OBJEXT)
+	-rm -f intel/*.lo
+	-rm -f mips/*.$(OBJEXT)
+	-rm -f mips/*.lo
+	-rm -f powerpc/*.$(OBJEXT)
+	-rm -f powerpc/*.lo
+
+distclean-compile:
+	-rm -f *.tab.c
+
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/png.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngerror.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngget.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngmem.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngpread.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngread.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngrio.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngrtran.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngrutil.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngset.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngtest.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngtrans.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngwio.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngwrite.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngwtran.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngwutil.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@arm/$(DEPDIR)/arm_init.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@arm/$(DEPDIR)/filter_neon.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@arm/$(DEPDIR)/filter_neon_intrinsics.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@arm/$(DEPDIR)/palette_neon_intrinsics.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@contrib/libtests/$(DEPDIR)/pngimage.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@contrib/libtests/$(DEPDIR)/pngstest.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@contrib/libtests/$(DEPDIR)/pngunknown.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@contrib/libtests/$(DEPDIR)/pngvalid.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@contrib/libtests/$(DEPDIR)/timepng.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@contrib/tools/$(DEPDIR)/png-fix-itxt.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@contrib/tools/$(DEPDIR)/pngcp.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@contrib/tools/$(DEPDIR)/pngfix.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@intel/$(DEPDIR)/filter_sse2_intrinsics.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@intel/$(DEPDIR)/intel_init.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@mips/$(DEPDIR)/filter_msa_intrinsics.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@mips/$(DEPDIR)/mips_init.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@powerpc/$(DEPDIR)/powerpc_init.Plo@am__quote@ # am--include-marker
+
+$(am__depfiles_remade):
+	@$(MKDIR_P) $(@D)
+	@echo '# dummy' >$@-t && $(am__mv) $@-t $@
+
+am--depfiles: $(am__depfiles_remade)
+
+.S.o:
+@am__fastdepCCAS_TRUE@	$(AM_V_CPPAS)depbase=`echo $@ | sed 's|[^/]*$$|$(DEPDIR)/&|;s|\.o$$||'`;\
+@am__fastdepCCAS_TRUE@	$(CPPASCOMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ $< &&\
+@am__fastdepCCAS_TRUE@	$(am__mv) $$depbase.Tpo $$depbase.Po
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS)source='$<' object='$@' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	DEPDIR=$(DEPDIR) $(CCASDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS@am__nodep@)$(CPPASCOMPILE) -c -o $@ $<
+
+.S.obj:
+@am__fastdepCCAS_TRUE@	$(AM_V_CPPAS)depbase=`echo $@ | sed 's|[^/]*$$|$(DEPDIR)/&|;s|\.obj$$||'`;\
+@am__fastdepCCAS_TRUE@	$(CPPASCOMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ `$(CYGPATH_W) '$<'` &&\
+@am__fastdepCCAS_TRUE@	$(am__mv) $$depbase.Tpo $$depbase.Po
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS)source='$<' object='$@' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	DEPDIR=$(DEPDIR) $(CCASDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS@am__nodep@)$(CPPASCOMPILE) -c -o $@ `$(CYGPATH_W) '$<'`
+
+.S.lo:
+@am__fastdepCCAS_TRUE@	$(AM_V_CPPAS)depbase=`echo $@ | sed 's|[^/]*$$|$(DEPDIR)/&|;s|\.lo$$||'`;\
+@am__fastdepCCAS_TRUE@	$(LTCPPASCOMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ $< &&\
+@am__fastdepCCAS_TRUE@	$(am__mv) $$depbase.Tpo $$depbase.Plo
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS)source='$<' object='$@' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCCAS_FALSE@	DEPDIR=$(DEPDIR) $(CCASDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCCAS_FALSE@	$(AM_V_CPPAS@am__nodep@)$(LTCPPASCOMPILE) -c -o $@ $<
+
+.c.o:
+@am__fastdepCC_TRUE@	$(AM_V_CC)depbase=`echo $@ | sed 's|[^/]*$$|$(DEPDIR)/&|;s|\.o$$||'`;\
+@am__fastdepCC_TRUE@	$(COMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ $< &&\
+@am__fastdepCC_TRUE@	$(am__mv) $$depbase.Tpo $$depbase.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='$<' object='$@' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(COMPILE) -c -o $@ $<
+
+.c.obj:
+@am__fastdepCC_TRUE@	$(AM_V_CC)depbase=`echo $@ | sed 's|[^/]*$$|$(DEPDIR)/&|;s|\.obj$$||'`;\
+@am__fastdepCC_TRUE@	$(COMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ `$(CYGPATH_W) '$<'` &&\
+@am__fastdepCC_TRUE@	$(am__mv) $$depbase.Tpo $$depbase.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='$<' object='$@' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(COMPILE) -c -o $@ `$(CYGPATH_W) '$<'`
+
+.c.lo:
+@am__fastdepCC_TRUE@	$(AM_V_CC)depbase=`echo $@ | sed 's|[^/]*$$|$(DEPDIR)/&|;s|\.lo$$||'`;\
+@am__fastdepCC_TRUE@	$(LTCOMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ $< &&\
+@am__fastdepCC_TRUE@	$(am__mv) $$depbase.Tpo $$depbase.Plo
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='$<' object='$@' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LTCOMPILE) -c -o $@ $<
+
+mostlyclean-libtool:
+	-rm -f *.lo
+
+clean-libtool:
+	-rm -rf .libs _libs
+	-rm -rf arm/.libs arm/_libs
+	-rm -rf intel/.libs intel/_libs
+	-rm -rf mips/.libs mips/_libs
+	-rm -rf powerpc/.libs powerpc/_libs
+
+distclean-libtool:
+	-rm -f libtool config.lt
+install-man3: $(dist_man_MANS)
+	@$(NORMAL_INSTALL)
+	@list1=''; \
+	list2='$(dist_man_MANS)'; \
+	test -n "$(man3dir)" \
+	  && test -n "`echo $$list1$$list2`" \
+	  || exit 0; \
+	echo " $(MKDIR_P) '$(DESTDIR)$(man3dir)'"; \
+	$(MKDIR_P) "$(DESTDIR)$(man3dir)" || exit 1; \
+	{ for i in $$list1; do echo "$$i"; done;  \
+	if test -n "$$list2"; then \
+	  for i in $$list2; do echo "$$i"; done \
+	    | sed -n '/\.3[a-z]*$$/p'; \
+	fi; \
+	} | while read p; do \
+	  if test -f $$p; then d=; else d="$(srcdir)/"; fi; \
+	  echo "$$d$$p"; echo "$$p"; \
+	done | \
+	sed -e 'n;s,.*/,,;p;h;s,.*\.,,;s,^[^3][0-9a-z]*$$,3,;x' \
+	      -e 's,\.[0-9a-z]*$$,,;$(transform);G;s,\n,.,' | \
+	sed 'N;N;s,\n, ,g' | { \
+	list=; while read file base inst; do \
+	  if test "$$base" = "$$inst"; then list="$$list $$file"; else \
+	    echo " $(INSTALL_DATA) '$$file' '$(DESTDIR)$(man3dir)/$$inst'"; \
+	    $(INSTALL_DATA) "$$file" "$(DESTDIR)$(man3dir)/$$inst" || exit $$?; \
+	  fi; \
+	done; \
+	for i in $$list; do echo "$$i"; done | $(am__base_list) | \
+	while read files; do \
+	  test -z "$$files" || { \
+	    echo " $(INSTALL_DATA) $$files '$(DESTDIR)$(man3dir)'"; \
+	    $(INSTALL_DATA) $$files "$(DESTDIR)$(man3dir)" || exit $$?; }; \
+	done; }
+
+uninstall-man3:
+	@$(NORMAL_UNINSTALL)
+	@list=''; test -n "$(man3dir)" || exit 0; \
+	files=`{ for i in $$list; do echo "$$i"; done; \
+	l2='$(dist_man_MANS)'; for i in $$l2; do echo "$$i"; done | \
+	  sed -n '/\.3[a-z]*$$/p'; \
+	} | sed -e 's,.*/,,;h;s,.*\.,,;s,^[^3][0-9a-z]*$$,3,;x' \
+	      -e 's,\.[0-9a-z]*$$,,;$(transform);G;s,\n,.,'`; \
+	dir='$(DESTDIR)$(man3dir)'; $(am__uninstall_files_from_dir)
+install-man5: $(dist_man_MANS)
+	@$(NORMAL_INSTALL)
+	@list1=''; \
+	list2='$(dist_man_MANS)'; \
+	test -n "$(man5dir)" \
+	  && test -n "`echo $$list1$$list2`" \
+	  || exit 0; \
+	echo " $(MKDIR_P) '$(DESTDIR)$(man5dir)'"; \
+	$(MKDIR_P) "$(DESTDIR)$(man5dir)" || exit 1; \
+	{ for i in $$list1; do echo "$$i"; done;  \
+	if test -n "$$list2"; then \
+	  for i in $$list2; do echo "$$i"; done \
+	    | sed -n '/\.5[a-z]*$$/p'; \
+	fi; \
+	} | while read p; do \
+	  if test -f $$p; then d=; else d="$(srcdir)/"; fi; \
+	  echo "$$d$$p"; echo "$$p"; \
+	done | \
+	sed -e 'n;s,.*/,,;p;h;s,.*\.,,;s,^[^5][0-9a-z]*$$,5,;x' \
+	      -e 's,\.[0-9a-z]*$$,,;$(transform);G;s,\n,.,' | \
+	sed 'N;N;s,\n, ,g' | { \
+	list=; while read file base inst; do \
+	  if test "$$base" = "$$inst"; then list="$$list $$file"; else \
+	    echo " $(INSTALL_DATA) '$$file' '$(DESTDIR)$(man5dir)/$$inst'"; \
+	    $(INSTALL_DATA) "$$file" "$(DESTDIR)$(man5dir)/$$inst" || exit $$?; \
+	  fi; \
+	done; \
+	for i in $$list; do echo "$$i"; done | $(am__base_list) | \
+	while read files; do \
+	  test -z "$$files" || { \
+	    echo " $(INSTALL_DATA) $$files '$(DESTDIR)$(man5dir)'"; \
+	    $(INSTALL_DATA) $$files "$(DESTDIR)$(man5dir)" || exit $$?; }; \
+	done; }
+
+uninstall-man5:
+	@$(NORMAL_UNINSTALL)
+	@list=''; test -n "$(man5dir)" || exit 0; \
+	files=`{ for i in $$list; do echo "$$i"; done; \
+	l2='$(dist_man_MANS)'; for i in $$l2; do echo "$$i"; done | \
+	  sed -n '/\.5[a-z]*$$/p'; \
+	} | sed -e 's,.*/,,;h;s,.*\.,,;s,^[^5][0-9a-z]*$$,5,;x' \
+	      -e 's,\.[0-9a-z]*$$,,;$(transform);G;s,\n,.,'`; \
+	dir='$(DESTDIR)$(man5dir)'; $(am__uninstall_files_from_dir)
+install-pkgconfigDATA: $(pkgconfig_DATA)
+	@$(NORMAL_INSTALL)
+	@list='$(pkgconfig_DATA)'; test -n "$(pkgconfigdir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(pkgconfigdir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(pkgconfigdir)" || exit 1; \
+	fi; \
+	for p in $$list; do \
+	  if test -f "$$p"; then d=; else d="$(srcdir)/"; fi; \
+	  echo "$$d$$p"; \
+	done | $(am__base_list) | \
+	while read files; do \
+	  echo " $(INSTALL_DATA) $$files '$(DESTDIR)$(pkgconfigdir)'"; \
+	  $(INSTALL_DATA) $$files "$(DESTDIR)$(pkgconfigdir)" || exit $$?; \
+	done
+
+uninstall-pkgconfigDATA:
+	@$(NORMAL_UNINSTALL)
+	@list='$(pkgconfig_DATA)'; test -n "$(pkgconfigdir)" || list=; \
+	files=`for p in $$list; do echo $$p; done | sed -e 's|^.*/||'`; \
+	dir='$(DESTDIR)$(pkgconfigdir)'; $(am__uninstall_files_from_dir)
+install-nodist_pkgincludeHEADERS: $(nodist_pkginclude_HEADERS)
+	@$(NORMAL_INSTALL)
+	@list='$(nodist_pkginclude_HEADERS)'; test -n "$(pkgincludedir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(pkgincludedir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(pkgincludedir)" || exit 1; \
+	fi; \
+	for p in $$list; do \
+	  if test -f "$$p"; then d=; else d="$(srcdir)/"; fi; \
+	  echo "$$d$$p"; \
+	done | $(am__base_list) | \
+	while read files; do \
+	  echo " $(INSTALL_HEADER) $$files '$(DESTDIR)$(pkgincludedir)'"; \
+	  $(INSTALL_HEADER) $$files "$(DESTDIR)$(pkgincludedir)" || exit $$?; \
+	done
+
+uninstall-nodist_pkgincludeHEADERS:
+	@$(NORMAL_UNINSTALL)
+	@list='$(nodist_pkginclude_HEADERS)'; test -n "$(pkgincludedir)" || list=; \
+	files=`for p in $$list; do echo $$p; done | sed -e 's|^.*/||'`; \
+	dir='$(DESTDIR)$(pkgincludedir)'; $(am__uninstall_files_from_dir)
+install-pkgincludeHEADERS: $(pkginclude_HEADERS)
+	@$(NORMAL_INSTALL)
+	@list='$(pkginclude_HEADERS)'; test -n "$(pkgincludedir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(pkgincludedir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(pkgincludedir)" || exit 1; \
+	fi; \
+	for p in $$list; do \
+	  if test -f "$$p"; then d=; else d="$(srcdir)/"; fi; \
+	  echo "$$d$$p"; \
+	done | $(am__base_list) | \
+	while read files; do \
+	  echo " $(INSTALL_HEADER) $$files '$(DESTDIR)$(pkgincludedir)'"; \
+	  $(INSTALL_HEADER) $$files "$(DESTDIR)$(pkgincludedir)" || exit $$?; \
+	done
+
+uninstall-pkgincludeHEADERS:
+	@$(NORMAL_UNINSTALL)
+	@list='$(pkginclude_HEADERS)'; test -n "$(pkgincludedir)" || list=; \
+	files=`for p in $$list; do echo $$p; done | sed -e 's|^.*/||'`; \
+	dir='$(DESTDIR)$(pkgincludedir)'; $(am__uninstall_files_from_dir)
+
+ID: $(am__tagged_files)
+	$(am__define_uniq_tagged_files); mkid -fID $$unique
+tags: tags-am
+TAGS: tags
+
+tags-am: $(TAGS_DEPENDENCIES) $(am__tagged_files)
+	set x; \
+	here=`pwd`; \
+	$(am__define_uniq_tagged_files); \
+	shift; \
+	if test -z "$(ETAGS_ARGS)$$*$$unique"; then :; else \
+	  test -n "$$unique" || unique=$$empty_fix; \
+	  if test $$# -gt 0; then \
+	    $(ETAGS) $(ETAGSFLAGS) $(AM_ETAGSFLAGS) $(ETAGS_ARGS) \
+	      "$$@" $$unique; \
+	  else \
+	    $(ETAGS) $(ETAGSFLAGS) $(AM_ETAGSFLAGS) $(ETAGS_ARGS) \
+	      $$unique; \
+	  fi; \
+	fi
+ctags: ctags-am
+
+CTAGS: ctags
+ctags-am: $(TAGS_DEPENDENCIES) $(am__tagged_files)
+	$(am__define_uniq_tagged_files); \
+	test -z "$(CTAGS_ARGS)$$unique" \
+	  || $(CTAGS) $(CTAGSFLAGS) $(AM_CTAGSFLAGS) $(CTAGS_ARGS) \
+	     $$unique
+
+GTAGS:
+	here=`$(am__cd) $(top_builddir) && pwd` \
+	  && $(am__cd) $(top_srcdir) \
+	  && gtags -i $(GTAGS_ARGS) "$$here"
+cscope: cscope.files
+	test ! -s cscope.files \
+	  || $(CSCOPE) -b -q $(AM_CSCOPEFLAGS) $(CSCOPEFLAGS) -i cscope.files $(CSCOPE_ARGS)
+clean-cscope:
+	-rm -f cscope.files
+cscope.files: clean-cscope cscopelist
+cscopelist: cscopelist-am
+
+cscopelist-am: $(am__tagged_files)
+	list='$(am__tagged_files)'; \
+	case "$(srcdir)" in \
+	  [\\/]* | ?:[\\/]*) sdir="$(srcdir)" ;; \
+	  *) sdir=$(subdir)/$(srcdir) ;; \
+	esac; \
+	for i in $$list; do \
+	  if test -f "$$i"; then \
+	    echo "$(subdir)/$$i"; \
+	  else \
+	    echo "$$sdir/$$i"; \
+	  fi; \
+	done >> $(top_builddir)/cscope.files
+
+distclean-tags:
+	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
+	-rm -f cscope.out cscope.in.out cscope.po.out cscope.files
+
+# Recover from deleted '.trs' file; this should ensure that
+# "rm -f foo.log; make foo.trs" re-run 'foo.test', and re-create
+# both 'foo.log' and 'foo.trs'.  Break the recipe in two subshells
+# to avoid problems with "make -n".
+.log.trs:
+	rm -f $< $@
+	$(MAKE) $(AM_MAKEFLAGS) $<
+
+# Leading 'am--fnord' is there to ensure the list of targets does not
+# expand to empty, as could happen e.g. with make check TESTS=''.
+am--fnord $(TEST_LOGS) $(TEST_LOGS:.log=.trs): $(am__force_recheck)
+am--force-recheck:
+	@:
+
+$(TEST_SUITE_LOG): $(TEST_LOGS)
+	@$(am__set_TESTS_bases); \
+	am__f_ok () { test -f "$$1" && test -r "$$1"; }; \
+	redo_bases=`for i in $$bases; do \
+	              am__f_ok $$i.trs && am__f_ok $$i.log || echo $$i; \
+	            done`; \
+	if test -n "$$redo_bases"; then \
+	  redo_logs=`for i in $$redo_bases; do echo $$i.log; done`; \
+	  redo_results=`for i in $$redo_bases; do echo $$i.trs; done`; \
+	  if $(am__make_dryrun); then :; else \
+	    rm -f $$redo_logs && rm -f $$redo_results || exit 1; \
+	  fi; \
+	fi; \
+	if test -n "$$am__remaking_logs"; then \
+	  echo "fatal: making $(TEST_SUITE_LOG): possible infinite" \
+	       "recursion detected" >&2; \
+	elif test -n "$$redo_logs"; then \
+	  am__remaking_logs=yes $(MAKE) $(AM_MAKEFLAGS) $$redo_logs; \
+	fi; \
+	if $(am__make_dryrun); then :; else \
+	  st=0;  \
+	  errmsg="fatal: making $(TEST_SUITE_LOG): failed to create"; \
+	  for i in $$redo_bases; do \
+	    test -f $$i.trs && test -r $$i.trs \
+	      || { echo "$$errmsg $$i.trs" >&2; st=1; }; \
+	    test -f $$i.log && test -r $$i.log \
+	      || { echo "$$errmsg $$i.log" >&2; st=1; }; \
+	  done; \
+	  test $$st -eq 0 || exit 1; \
+	fi
+	@$(am__sh_e_setup); $(am__tty_colors); $(am__set_TESTS_bases); \
+	ws='[ 	]'; \
+	results=`for b in $$bases; do echo $$b.trs; done`; \
+	test -n "$$results" || results=/dev/null; \
+	all=`  grep "^$$ws*:test-result:"           $$results | wc -l`; \
+	pass=` grep "^$$ws*:test-result:$$ws*PASS"  $$results | wc -l`; \
+	fail=` grep "^$$ws*:test-result:$$ws*FAIL"  $$results | wc -l`; \
+	skip=` grep "^$$ws*:test-result:$$ws*SKIP"  $$results | wc -l`; \
+	xfail=`grep "^$$ws*:test-result:$$ws*XFAIL" $$results | wc -l`; \
+	xpass=`grep "^$$ws*:test-result:$$ws*XPASS" $$results | wc -l`; \
+	error=`grep "^$$ws*:test-result:$$ws*ERROR" $$results | wc -l`; \
+	if test `expr $$fail + $$xpass + $$error` -eq 0; then \
+	  success=true; \
+	else \
+	  success=false; \
+	fi; \
+	br='==================='; br=$$br$$br$$br$$br; \
+	result_count () \
+	{ \
+	    if test x"$$1" = x"--maybe-color"; then \
+	      maybe_colorize=yes; \
+	    elif test x"$$1" = x"--no-color"; then \
+	      maybe_colorize=no; \
+	    else \
+	      echo "$@: invalid 'result_count' usage" >&2; exit 4; \
+	    fi; \
+	    shift; \
+	    desc=$$1 count=$$2; \
+	    if test $$maybe_colorize = yes && test $$count -gt 0; then \
+	      color_start=$$3 color_end=$$std; \
+	    else \
+	      color_start= color_end=; \
+	    fi; \
+	    echo "$${color_start}# $$desc $$count$${color_end}"; \
+	}; \
+	create_testsuite_report () \
+	{ \
+	  result_count $$1 "TOTAL:" $$all   "$$brg"; \
+	  result_count $$1 "PASS: " $$pass  "$$grn"; \
+	  result_count $$1 "SKIP: " $$skip  "$$blu"; \
+	  result_count $$1 "XFAIL:" $$xfail "$$lgn"; \
+	  result_count $$1 "FAIL: " $$fail  "$$red"; \
+	  result_count $$1 "XPASS:" $$xpass "$$red"; \
+	  result_count $$1 "ERROR:" $$error "$$mgn"; \
+	}; \
+	{								\
+	  echo "$(PACKAGE_STRING): $(subdir)/$(TEST_SUITE_LOG)" |	\
+	    $(am__rst_title);						\
+	  create_testsuite_report --no-color;				\
+	  echo;								\
+	  echo ".. contents:: :depth: 2";				\
+	  echo;								\
+	  for b in $$bases; do echo $$b; done				\
+	    | $(am__create_global_log);					\
+	} >$(TEST_SUITE_LOG).tmp || exit 1;				\
+	mv $(TEST_SUITE_LOG).tmp $(TEST_SUITE_LOG);			\
+	if $$success; then						\
+	  col="$$grn";							\
+	 else								\
+	  col="$$red";							\
+	  test x"$$VERBOSE" = x || cat $(TEST_SUITE_LOG);		\
+	fi;								\
+	echo "$${col}$$br$${std}"; 					\
+	echo "$${col}Testsuite summary for $(PACKAGE_STRING)$${std}";	\
+	echo "$${col}$$br$${std}"; 					\
+	create_testsuite_report --maybe-color;				\
+	echo "$$col$$br$$std";						\
+	if $$success; then :; else					\
+	  echo "$${col}See $(subdir)/$(TEST_SUITE_LOG)$${std}";		\
+	  if test -n "$(PACKAGE_BUGREPORT)"; then			\
+	    echo "$${col}Please report to $(PACKAGE_BUGREPORT)$${std}";	\
+	  fi;								\
+	  echo "$$col$$br$$std";					\
+	fi;								\
+	$$success || exit 1
+
+check-TESTS: $(check_PROGRAMS)
+	@list='$(RECHECK_LOGS)';           test -z "$$list" || rm -f $$list
+	@list='$(RECHECK_LOGS:.log=.trs)'; test -z "$$list" || rm -f $$list
+	@test -z "$(TEST_SUITE_LOG)" || rm -f $(TEST_SUITE_LOG)
+	@set +e; $(am__set_TESTS_bases); \
+	log_list=`for i in $$bases; do echo $$i.log; done`; \
+	trs_list=`for i in $$bases; do echo $$i.trs; done`; \
+	log_list=`echo $$log_list`; trs_list=`echo $$trs_list`; \
+	$(MAKE) $(AM_MAKEFLAGS) $(TEST_SUITE_LOG) TEST_LOGS="$$log_list"; \
+	exit $$?;
+recheck: all $(check_PROGRAMS)
+	@test -z "$(TEST_SUITE_LOG)" || rm -f $(TEST_SUITE_LOG)
+	@set +e; $(am__set_TESTS_bases); \
+	bases=`for i in $$bases; do echo $$i; done \
+	         | $(am__list_recheck_tests)` || exit 1; \
+	log_list=`for i in $$bases; do echo $$i.log; done`; \
+	log_list=`echo $$log_list`; \
+	$(MAKE) $(AM_MAKEFLAGS) $(TEST_SUITE_LOG) \
+	        am__force_recheck=am--force-recheck \
+	        TEST_LOGS="$$log_list"; \
+	exit $$?
+tests/pngtest.log: tests/pngtest
+	@p='tests/pngtest'; \
+	b='tests/pngtest'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngtest-badpngs.log: tests/pngtest-badpngs
+	@p='tests/pngtest-badpngs'; \
+	b='tests/pngtest-badpngs'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-16-to-8.log: tests/pngvalid-gamma-16-to-8
+	@p='tests/pngvalid-gamma-16-to-8'; \
+	b='tests/pngvalid-gamma-16-to-8'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-alpha-mode.log: tests/pngvalid-gamma-alpha-mode
+	@p='tests/pngvalid-gamma-alpha-mode'; \
+	b='tests/pngvalid-gamma-alpha-mode'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-background.log: tests/pngvalid-gamma-background
+	@p='tests/pngvalid-gamma-background'; \
+	b='tests/pngvalid-gamma-background'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-expand16-alpha-mode.log: tests/pngvalid-gamma-expand16-alpha-mode
+	@p='tests/pngvalid-gamma-expand16-alpha-mode'; \
+	b='tests/pngvalid-gamma-expand16-alpha-mode'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-expand16-background.log: tests/pngvalid-gamma-expand16-background
+	@p='tests/pngvalid-gamma-expand16-background'; \
+	b='tests/pngvalid-gamma-expand16-background'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-expand16-transform.log: tests/pngvalid-gamma-expand16-transform
+	@p='tests/pngvalid-gamma-expand16-transform'; \
+	b='tests/pngvalid-gamma-expand16-transform'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-sbit.log: tests/pngvalid-gamma-sbit
+	@p='tests/pngvalid-gamma-sbit'; \
+	b='tests/pngvalid-gamma-sbit'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-threshold.log: tests/pngvalid-gamma-threshold
+	@p='tests/pngvalid-gamma-threshold'; \
+	b='tests/pngvalid-gamma-threshold'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-transform.log: tests/pngvalid-gamma-transform
+	@p='tests/pngvalid-gamma-transform'; \
+	b='tests/pngvalid-gamma-transform'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-progressive-size.log: tests/pngvalid-progressive-size
+	@p='tests/pngvalid-progressive-size'; \
+	b='tests/pngvalid-progressive-size'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-progressive-interlace-standard.log: tests/pngvalid-progressive-interlace-standard
+	@p='tests/pngvalid-progressive-interlace-standard'; \
+	b='tests/pngvalid-progressive-interlace-standard'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-transform.log: tests/pngvalid-transform
+	@p='tests/pngvalid-transform'; \
+	b='tests/pngvalid-transform'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-progressive-standard.log: tests/pngvalid-progressive-standard
+	@p='tests/pngvalid-progressive-standard'; \
+	b='tests/pngvalid-progressive-standard'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-standard.log: tests/pngvalid-standard
+	@p='tests/pngvalid-standard'; \
+	b='tests/pngvalid-standard'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-1.8.log: tests/pngstest-1.8
+	@p='tests/pngstest-1.8'; \
+	b='tests/pngstest-1.8'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-1.8-alpha.log: tests/pngstest-1.8-alpha
+	@p='tests/pngstest-1.8-alpha'; \
+	b='tests/pngstest-1.8-alpha'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-linear.log: tests/pngstest-linear
+	@p='tests/pngstest-linear'; \
+	b='tests/pngstest-linear'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-linear-alpha.log: tests/pngstest-linear-alpha
+	@p='tests/pngstest-linear-alpha'; \
+	b='tests/pngstest-linear-alpha'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-none.log: tests/pngstest-none
+	@p='tests/pngstest-none'; \
+	b='tests/pngstest-none'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-none-alpha.log: tests/pngstest-none-alpha
+	@p='tests/pngstest-none-alpha'; \
+	b='tests/pngstest-none-alpha'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-sRGB.log: tests/pngstest-sRGB
+	@p='tests/pngstest-sRGB'; \
+	b='tests/pngstest-sRGB'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-sRGB-alpha.log: tests/pngstest-sRGB-alpha
+	@p='tests/pngstest-sRGB-alpha'; \
+	b='tests/pngstest-sRGB-alpha'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-IDAT.log: tests/pngunknown-IDAT
+	@p='tests/pngunknown-IDAT'; \
+	b='tests/pngunknown-IDAT'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-discard.log: tests/pngunknown-discard
+	@p='tests/pngunknown-discard'; \
+	b='tests/pngunknown-discard'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-if-safe.log: tests/pngunknown-if-safe
+	@p='tests/pngunknown-if-safe'; \
+	b='tests/pngunknown-if-safe'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-sAPI.log: tests/pngunknown-sAPI
+	@p='tests/pngunknown-sAPI'; \
+	b='tests/pngunknown-sAPI'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-sTER.log: tests/pngunknown-sTER
+	@p='tests/pngunknown-sTER'; \
+	b='tests/pngunknown-sTER'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-save.log: tests/pngunknown-save
+	@p='tests/pngunknown-save'; \
+	b='tests/pngunknown-save'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-vpAg.log: tests/pngunknown-vpAg
+	@p='tests/pngunknown-vpAg'; \
+	b='tests/pngunknown-vpAg'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngimage-quick.log: tests/pngimage-quick
+	@p='tests/pngimage-quick'; \
+	b='tests/pngimage-quick'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngimage-full.log: tests/pngimage-full
+	@p='tests/pngimage-full'; \
+	b='tests/pngimage-full'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+.test.log:
+	@p='$<'; \
+	$(am__set_b); \
+	$(am__check_pre) $(TEST_LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_TEST_LOG_DRIVER_FLAGS) $(TEST_LOG_DRIVER_FLAGS) -- $(TEST_LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+@am__EXEEXT_TRUE@.test$(EXEEXT).log:
+@am__EXEEXT_TRUE@	@p='$<'; \
+@am__EXEEXT_TRUE@	$(am__set_b); \
+@am__EXEEXT_TRUE@	$(am__check_pre) $(TEST_LOG_DRIVER) --test-name "$$f" \
+@am__EXEEXT_TRUE@	--log-file $$b.log --trs-file $$b.trs \
+@am__EXEEXT_TRUE@	$(am__common_driver_flags) $(AM_TEST_LOG_DRIVER_FLAGS) $(TEST_LOG_DRIVER_FLAGS) -- $(TEST_LOG_COMPILE) \
+@am__EXEEXT_TRUE@	"$$tst" $(AM_TESTS_FD_REDIRECT)
+
+distdir: $(BUILT_SOURCES)
+	$(MAKE) $(AM_MAKEFLAGS) distdir-am
+
+distdir-am: $(DISTFILES)
+	$(am__remove_distdir)
+	test -d "$(distdir)" || mkdir "$(distdir)"
+	@srcdirstrip=`echo "$(srcdir)" | sed 's/[].[^$$\\*]/\\\\&/g'`; \
+	topsrcdirstrip=`echo "$(top_srcdir)" | sed 's/[].[^$$\\*]/\\\\&/g'`; \
+	list='$(DISTFILES)'; \
+	  dist_files=`for file in $$list; do echo $$file; done | \
+	  sed -e "s|^$$srcdirstrip/||;t" \
+	      -e "s|^$$topsrcdirstrip/|$(top_builddir)/|;t"`; \
+	case $$dist_files in \
+	  */*) $(MKDIR_P) `echo "$$dist_files" | \
+			   sed '/\//!d;s|^|$(distdir)/|;s,/[^/]*$$,,' | \
+			   sort -u` ;; \
+	esac; \
+	for file in $$dist_files; do \
+	  if test -f $$file || test -d $$file; then d=.; else d=$(srcdir); fi; \
+	  if test -d $$d/$$file; then \
+	    dir=`echo "/$$file" | sed -e 's,/[^/]*$$,,'`; \
+	    if test -d "$(distdir)/$$file"; then \
+	      find "$(distdir)/$$file" -type d ! -perm -700 -exec chmod u+rwx {} \;; \
+	    fi; \
+	    if test -d $(srcdir)/$$file && test $$d != $(srcdir); then \
+	      cp -fpR $(srcdir)/$$file "$(distdir)$$dir" || exit 1; \
+	      find "$(distdir)/$$file" -type d ! -perm -700 -exec chmod u+rwx {} \;; \
+	    fi; \
+	    cp -fpR $$d/$$file "$(distdir)$$dir" || exit 1; \
+	  else \
+	    test -f "$(distdir)/$$file" \
+	    || cp -p $$d/$$file "$(distdir)/$$file" \
+	    || exit 1; \
+	  fi; \
+	done
+	$(MAKE) $(AM_MAKEFLAGS) \
+	  top_distdir="$(top_distdir)" distdir="$(distdir)" \
+	  dist-hook
+	-test -n "$(am__skip_mode_fix)" \
+	|| find "$(distdir)" -type d ! -perm -755 \
+		-exec chmod u+rwx,go+rx {} \; -o \
+	  ! -type d ! -perm -444 -links 1 -exec chmod a+r {} \; -o \
+	  ! -type d ! -perm -400 -exec chmod a+r {} \; -o \
+	  ! -type d ! -perm -444 -exec $(install_sh) -c -m a+r {} {} \; \
+	|| chmod -R a+r "$(distdir)"
+dist-gzip: distdir
+	tardir=$(distdir) && $(am__tar) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).tar.gz
+	$(am__post_remove_distdir)
+
+dist-bzip2: distdir
+	tardir=$(distdir) && $(am__tar) | BZIP2=$${BZIP2--9} bzip2 -c >$(distdir).tar.bz2
+	$(am__post_remove_distdir)
+
+dist-lzip: distdir
+	tardir=$(distdir) && $(am__tar) | lzip -c $${LZIP_OPT--9} >$(distdir).tar.lz
+	$(am__post_remove_distdir)
+dist-xz: distdir
+	tardir=$(distdir) && $(am__tar) | XZ_OPT=$${XZ_OPT--e} xz -c >$(distdir).tar.xz
+	$(am__post_remove_distdir)
+
+dist-tarZ: distdir
+	@echo WARNING: "Support for distribution archives compressed with" \
+		       "legacy program 'compress' is deprecated." >&2
+	@echo WARNING: "It will be removed altogether in Automake 2.0" >&2
+	tardir=$(distdir) && $(am__tar) | compress -c >$(distdir).tar.Z
+	$(am__post_remove_distdir)
+
+dist-shar: distdir
+	@echo WARNING: "Support for shar distribution archives is" \
+	               "deprecated." >&2
+	@echo WARNING: "It will be removed altogether in Automake 2.0" >&2
+	shar $(distdir) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).shar.gz
+	$(am__post_remove_distdir)
+
+dist-zip: distdir
+	-rm -f $(distdir).zip
+	zip -rq $(distdir).zip $(distdir)
+	$(am__post_remove_distdir)
+
+dist dist-all:
+	$(MAKE) $(AM_MAKEFLAGS) $(DIST_TARGETS) am__post_remove_distdir='@:'
+	$(am__post_remove_distdir)
+
+# This target untars the dist file and tries a VPATH configuration.  Then
+# it guarantees that the distribution is self-contained by making another
+# tarfile.
+distcheck: dist
+	case '$(DIST_ARCHIVES)' in \
+	*.tar.gz*) \
+	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).tar.gz | $(am__untar) ;;\
+	*.tar.bz2*) \
+	  bzip2 -dc $(distdir).tar.bz2 | $(am__untar) ;;\
+	*.tar.lz*) \
+	  lzip -dc $(distdir).tar.lz | $(am__untar) ;;\
+	*.tar.xz*) \
+	  xz -dc $(distdir).tar.xz | $(am__untar) ;;\
+	*.tar.Z*) \
+	  uncompress -c $(distdir).tar.Z | $(am__untar) ;;\
+	*.shar.gz*) \
+	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).shar.gz | unshar ;;\
+	*.zip*) \
+	  unzip $(distdir).zip ;;\
+	esac
+	chmod -R a-w $(distdir)
+	chmod u+w $(distdir)
+	mkdir $(distdir)/_build $(distdir)/_build/sub $(distdir)/_inst
+	chmod a-w $(distdir)
+	test -d $(distdir)/_build || exit 0; \
+	dc_install_base=`$(am__cd) $(distdir)/_inst && pwd | sed -e 's,^[^:\\/]:[\\/],/,'` \
+	  && dc_destdir="$${TMPDIR-/tmp}/am-dc-$$$$/" \
+	  && am__cwd=`pwd` \
+	  && $(am__cd) $(distdir)/_build/sub \
+	  && ../../configure \
+	    $(AM_DISTCHECK_CONFIGURE_FLAGS) \
+	    $(DISTCHECK_CONFIGURE_FLAGS) \
+	    --srcdir=../.. --prefix="$$dc_install_base" \
+	  && $(MAKE) $(AM_MAKEFLAGS) \
+	  && $(MAKE) $(AM_MAKEFLAGS) dvi \
+	  && $(MAKE) $(AM_MAKEFLAGS) check \
+	  && $(MAKE) $(AM_MAKEFLAGS) install \
+	  && $(MAKE) $(AM_MAKEFLAGS) installcheck \
+	  && $(MAKE) $(AM_MAKEFLAGS) uninstall \
+	  && $(MAKE) $(AM_MAKEFLAGS) distuninstallcheck_dir="$$dc_install_base" \
+	        distuninstallcheck \
+	  && chmod -R a-w "$$dc_install_base" \
+	  && ({ \
+	       (cd ../.. && umask 077 && mkdir "$$dc_destdir") \
+	       && $(MAKE) $(AM_MAKEFLAGS) DESTDIR="$$dc_destdir" install \
+	       && $(MAKE) $(AM_MAKEFLAGS) DESTDIR="$$dc_destdir" uninstall \
+	       && $(MAKE) $(AM_MAKEFLAGS) DESTDIR="$$dc_destdir" \
+	            distuninstallcheck_dir="$$dc_destdir" distuninstallcheck; \
+	      } || { rm -rf "$$dc_destdir"; exit 1; }) \
+	  && rm -rf "$$dc_destdir" \
+	  && $(MAKE) $(AM_MAKEFLAGS) dist \
+	  && rm -rf $(DIST_ARCHIVES) \
+	  && $(MAKE) $(AM_MAKEFLAGS) distcleancheck \
+	  && cd "$$am__cwd" \
+	  || exit 1
+	$(am__post_remove_distdir)
+	@(echo "$(distdir) archives ready for distribution: "; \
+	  list='$(DIST_ARCHIVES)'; for i in $$list; do echo $$i; done) | \
+	  sed -e 1h -e 1s/./=/g -e 1p -e 1x -e '$$p' -e '$$x'
+distuninstallcheck:
+	@test -n '$(distuninstallcheck_dir)' || { \
+	  echo 'ERROR: trying to run $@ with an empty' \
+	       '$$(distuninstallcheck_dir)' >&2; \
+	  exit 1; \
+	}; \
+	$(am__cd) '$(distuninstallcheck_dir)' || { \
+	  echo 'ERROR: cannot chdir into $(distuninstallcheck_dir)' >&2; \
+	  exit 1; \
+	}; \
+	test `$(am__distuninstallcheck_listfiles) | wc -l` -eq 0 \
+	   || { echo "ERROR: files left after uninstall:" ; \
+	        if test -n "$(DESTDIR)"; then \
+	          echo "  (check DESTDIR support)"; \
+	        fi ; \
+	        $(distuninstallcheck_listfiles) ; \
+	        exit 1; } >&2
+distcleancheck: distclean
+	@if test '$(srcdir)' = . ; then \
+	  echo "ERROR: distcleancheck can only run from a VPATH build" ; \
+	  exit 1 ; \
+	fi
+	@test `$(distcleancheck_listfiles) | wc -l` -eq 0 \
+	  || { echo "ERROR: files left in build directory after distclean:" ; \
+	       $(distcleancheck_listfiles) ; \
+	       exit 1; } >&2
+check-am: all-am
+	$(MAKE) $(AM_MAKEFLAGS) $(check_PROGRAMS)
+	$(MAKE) $(AM_MAKEFLAGS) check-TESTS
+check: $(BUILT_SOURCES)
+	$(MAKE) $(AM_MAKEFLAGS) check-am
+all-am: Makefile $(PROGRAMS) $(LTLIBRARIES) $(SCRIPTS) $(MANS) $(DATA) \
+		$(HEADERS) config.h
+install-binPROGRAMS: install-libLTLIBRARIES
+
+installdirs:
+	for dir in "$(DESTDIR)$(bindir)" "$(DESTDIR)$(libdir)" "$(DESTDIR)$(bindir)" "$(DESTDIR)$(man3dir)" "$(DESTDIR)$(man5dir)" "$(DESTDIR)$(pkgconfigdir)" "$(DESTDIR)$(pkgincludedir)" "$(DESTDIR)$(pkgincludedir)"; do \
+	  test -z "$$dir" || $(MKDIR_P) "$$dir"; \
+	done
+install: $(BUILT_SOURCES)
+	$(MAKE) $(AM_MAKEFLAGS) install-am
+install-exec: install-exec-am
+install-data: install-data-am
+uninstall: uninstall-am
+
+install-am: all-am
+	@$(MAKE) $(AM_MAKEFLAGS) install-exec-am install-data-am
+
+installcheck: installcheck-am
+install-strip:
+	if test -z '$(STRIP)'; then \
+	  $(MAKE) $(AM_MAKEFLAGS) INSTALL_PROGRAM="$(INSTALL_STRIP_PROGRAM)" \
+	    install_sh_PROGRAM="$(INSTALL_STRIP_PROGRAM)" INSTALL_STRIP_FLAG=-s \
+	      install; \
+	else \
+	  $(MAKE) $(AM_MAKEFLAGS) INSTALL_PROGRAM="$(INSTALL_STRIP_PROGRAM)" \
+	    install_sh_PROGRAM="$(INSTALL_STRIP_PROGRAM)" INSTALL_STRIP_FLAG=-s \
+	    "INSTALL_PROGRAM_ENV=STRIPPROG='$(STRIP)'" install; \
+	fi
+mostlyclean-generic:
+	-test -z "$(TEST_LOGS)" || rm -f $(TEST_LOGS)
+	-test -z "$(TEST_LOGS:.log=.trs)" || rm -f $(TEST_LOGS:.log=.trs)
+	-test -z "$(TEST_SUITE_LOG)" || rm -f $(TEST_SUITE_LOG)
+
+clean-generic:
+	-test -z "$(CLEANFILES)" || rm -f $(CLEANFILES)
+
+distclean-generic:
+	-test -z "$(CONFIG_CLEAN_FILES)" || rm -f $(CONFIG_CLEAN_FILES)
+	-test . = "$(srcdir)" || test -z "$(CONFIG_CLEAN_VPATH_FILES)" || rm -f $(CONFIG_CLEAN_VPATH_FILES)
+	-rm -f arm/$(DEPDIR)/$(am__dirstamp)
+	-rm -f arm/$(am__dirstamp)
+	-rm -f contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+	-rm -f contrib/libtests/$(am__dirstamp)
+	-rm -f contrib/tools/$(DEPDIR)/$(am__dirstamp)
+	-rm -f contrib/tools/$(am__dirstamp)
+	-rm -f intel/$(DEPDIR)/$(am__dirstamp)
+	-rm -f intel/$(am__dirstamp)
+	-rm -f mips/$(DEPDIR)/$(am__dirstamp)
+	-rm -f mips/$(am__dirstamp)
+	-rm -f powerpc/$(DEPDIR)/$(am__dirstamp)
+	-rm -f powerpc/$(am__dirstamp)
+
+maintainer-clean-generic:
+	@echo "This command is intended for maintainers to use"
+	@echo "it deletes files that may require special tools to rebuild."
+	-test -z "$(BUILT_SOURCES)" || rm -f $(BUILT_SOURCES)
+	-test -z "$(MAINTAINERCLEANFILES)" || rm -f $(MAINTAINERCLEANFILES)
+@DO_INSTALL_LIBPNG_CONFIG_FALSE@@DO_INSTALL_LINKS_FALSE@install-exec-hook:
+@DO_INSTALL_LIBPNG_PC_FALSE@@DO_INSTALL_LINKS_FALSE@install-data-hook:
+@DO_INSTALL_LIBPNG_CONFIG_FALSE@@DO_INSTALL_LIBPNG_PC_FALSE@@DO_INSTALL_LINKS_FALSE@uninstall-hook:
+clean: clean-am
+
+clean-am: clean-binPROGRAMS clean-checkPROGRAMS clean-generic \
+	clean-libLTLIBRARIES clean-libtool mostlyclean-am
+
+distclean: distclean-am
+	-rm -f $(am__CONFIG_DISTCLEAN_FILES)
+		-rm -f ./$(DEPDIR)/png.Plo
+	-rm -f ./$(DEPDIR)/pngerror.Plo
+	-rm -f ./$(DEPDIR)/pngget.Plo
+	-rm -f ./$(DEPDIR)/pngmem.Plo
+	-rm -f ./$(DEPDIR)/pngpread.Plo
+	-rm -f ./$(DEPDIR)/pngread.Plo
+	-rm -f ./$(DEPDIR)/pngrio.Plo
+	-rm -f ./$(DEPDIR)/pngrtran.Plo
+	-rm -f ./$(DEPDIR)/pngrutil.Plo
+	-rm -f ./$(DEPDIR)/pngset.Plo
+	-rm -f ./$(DEPDIR)/pngtest.Po
+	-rm -f ./$(DEPDIR)/pngtrans.Plo
+	-rm -f ./$(DEPDIR)/pngwio.Plo
+	-rm -f ./$(DEPDIR)/pngwrite.Plo
+	-rm -f ./$(DEPDIR)/pngwtran.Plo
+	-rm -f ./$(DEPDIR)/pngwutil.Plo
+	-rm -f arm/$(DEPDIR)/arm_init.Plo
+	-rm -f arm/$(DEPDIR)/filter_neon.Plo
+	-rm -f arm/$(DEPDIR)/filter_neon_intrinsics.Plo
+	-rm -f arm/$(DEPDIR)/palette_neon_intrinsics.Plo
+	-rm -f contrib/libtests/$(DEPDIR)/pngimage.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngstest.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngunknown.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngvalid.Po
+	-rm -f contrib/libtests/$(DEPDIR)/timepng.Po
+	-rm -f contrib/tools/$(DEPDIR)/png-fix-itxt.Po
+	-rm -f contrib/tools/$(DEPDIR)/pngcp.Po
+	-rm -f contrib/tools/$(DEPDIR)/pngfix.Po
+	-rm -f intel/$(DEPDIR)/filter_sse2_intrinsics.Plo
+	-rm -f intel/$(DEPDIR)/intel_init.Plo
+	-rm -f mips/$(DEPDIR)/filter_msa_intrinsics.Plo
+	-rm -f mips/$(DEPDIR)/mips_init.Plo
+	-rm -f powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo
+	-rm -f powerpc/$(DEPDIR)/powerpc_init.Plo
+	-rm -f Makefile
+distclean-am: clean-am distclean-compile distclean-generic \
+	distclean-hdr distclean-libtool distclean-tags
+
+dvi: dvi-am
+
+dvi-am:
+
+html: html-am
+
+html-am:
+
+info: info-am
+
+info-am:
+
+install-data-am: install-man install-nodist_pkgincludeHEADERS \
+	install-pkgconfigDATA install-pkgincludeHEADERS
+	@$(NORMAL_INSTALL)
+	$(MAKE) $(AM_MAKEFLAGS) install-data-hook
+install-dvi: install-dvi-am
+
+install-dvi-am:
+
+install-exec-am: install-binPROGRAMS install-binSCRIPTS \
+	install-libLTLIBRARIES
+	@$(NORMAL_INSTALL)
+	$(MAKE) $(AM_MAKEFLAGS) install-exec-hook
+install-html: install-html-am
+
+install-html-am:
+
+install-info: install-info-am
+
+install-info-am:
+
+install-man: install-man3 install-man5
+
+install-pdf: install-pdf-am
+
+install-pdf-am:
+
+install-ps: install-ps-am
+
+install-ps-am:
+
+installcheck-am:
+
+maintainer-clean: maintainer-clean-am
+	-rm -f $(am__CONFIG_DISTCLEAN_FILES)
+	-rm -rf $(top_srcdir)/autom4te.cache
+		-rm -f ./$(DEPDIR)/png.Plo
+	-rm -f ./$(DEPDIR)/pngerror.Plo
+	-rm -f ./$(DEPDIR)/pngget.Plo
+	-rm -f ./$(DEPDIR)/pngmem.Plo
+	-rm -f ./$(DEPDIR)/pngpread.Plo
+	-rm -f ./$(DEPDIR)/pngread.Plo
+	-rm -f ./$(DEPDIR)/pngrio.Plo
+	-rm -f ./$(DEPDIR)/pngrtran.Plo
+	-rm -f ./$(DEPDIR)/pngrutil.Plo
+	-rm -f ./$(DEPDIR)/pngset.Plo
+	-rm -f ./$(DEPDIR)/pngtest.Po
+	-rm -f ./$(DEPDIR)/pngtrans.Plo
+	-rm -f ./$(DEPDIR)/pngwio.Plo
+	-rm -f ./$(DEPDIR)/pngwrite.Plo
+	-rm -f ./$(DEPDIR)/pngwtran.Plo
+	-rm -f ./$(DEPDIR)/pngwutil.Plo
+	-rm -f arm/$(DEPDIR)/arm_init.Plo
+	-rm -f arm/$(DEPDIR)/filter_neon.Plo
+	-rm -f arm/$(DEPDIR)/filter_neon_intrinsics.Plo
+	-rm -f arm/$(DEPDIR)/palette_neon_intrinsics.Plo
+	-rm -f contrib/libtests/$(DEPDIR)/pngimage.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngstest.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngunknown.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngvalid.Po
+	-rm -f contrib/libtests/$(DEPDIR)/timepng.Po
+	-rm -f contrib/tools/$(DEPDIR)/png-fix-itxt.Po
+	-rm -f contrib/tools/$(DEPDIR)/pngcp.Po
+	-rm -f contrib/tools/$(DEPDIR)/pngfix.Po
+	-rm -f intel/$(DEPDIR)/filter_sse2_intrinsics.Plo
+	-rm -f intel/$(DEPDIR)/intel_init.Plo
+	-rm -f mips/$(DEPDIR)/filter_msa_intrinsics.Plo
+	-rm -f mips/$(DEPDIR)/mips_init.Plo
+	-rm -f powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo
+	-rm -f powerpc/$(DEPDIR)/powerpc_init.Plo
+	-rm -f Makefile
+maintainer-clean-am: distclean-am maintainer-clean-generic
+
+mostlyclean: mostlyclean-am
+
+mostlyclean-am: mostlyclean-compile mostlyclean-generic \
+	mostlyclean-libtool
+
+pdf: pdf-am
+
+pdf-am:
+
+ps: ps-am
+
+ps-am:
+
+uninstall-am: uninstall-binPROGRAMS uninstall-binSCRIPTS \
+	uninstall-libLTLIBRARIES uninstall-man \
+	uninstall-nodist_pkgincludeHEADERS uninstall-pkgconfigDATA \
+	uninstall-pkgincludeHEADERS
+	@$(NORMAL_INSTALL)
+	$(MAKE) $(AM_MAKEFLAGS) uninstall-hook
+uninstall-man: uninstall-man3 uninstall-man5
+
+.MAKE: all check check-am install install-am install-data-am \
+	install-exec-am install-strip uninstall-am
+
+.PHONY: CTAGS GTAGS TAGS all all-am am--depfiles am--refresh check \
+	check-TESTS check-am clean clean-binPROGRAMS \
+	clean-checkPROGRAMS clean-cscope clean-generic \
+	clean-libLTLIBRARIES clean-libtool cscope cscopelist-am ctags \
+	ctags-am dist dist-all dist-bzip2 dist-gzip dist-hook \
+	dist-lzip dist-shar dist-tarZ dist-xz dist-zip distcheck \
+	distclean distclean-compile distclean-generic distclean-hdr \
+	distclean-libtool distclean-tags distcleancheck distdir \
+	distuninstallcheck dvi dvi-am html html-am info info-am \
+	install install-am install-binPROGRAMS install-binSCRIPTS \
+	install-data install-data-am install-data-hook install-dvi \
+	install-dvi-am install-exec install-exec-am install-exec-hook \
+	install-html install-html-am install-info install-info-am \
+	install-libLTLIBRARIES install-man install-man3 install-man5 \
+	install-nodist_pkgincludeHEADERS install-pdf install-pdf-am \
+	install-pkgconfigDATA install-pkgincludeHEADERS install-ps \
+	install-ps-am install-strip installcheck installcheck-am \
+	installdirs maintainer-clean maintainer-clean-generic \
+	mostlyclean mostlyclean-compile mostlyclean-generic \
+	mostlyclean-libtool pdf pdf-am ps ps-am recheck tags tags-am \
+	uninstall uninstall-am uninstall-binPROGRAMS \
+	uninstall-binSCRIPTS uninstall-hook uninstall-libLTLIBRARIES \
+	uninstall-man uninstall-man3 uninstall-man5 \
+	uninstall-nodist_pkgincludeHEADERS uninstall-pkgconfigDATA \
+	uninstall-pkgincludeHEADERS
+
+.PRECIOUS: Makefile
+
+
+$(PNGLIB_BASENAME).pc: libpng.pc
+	cp libpng.pc $@
+
+$(PNGLIB_BASENAME)-config: libpng-config
+	cp libpng-config $@
+
+scripts/sym.out scripts/vers.out: png.h pngconf.h pnglibconf.h
+scripts/prefix.out: png.h pngconf.h pnglibconf.out
+scripts/symbols.out: png.h pngconf.h $(srcdir)/scripts/pnglibconf.h.prebuilt
+scripts/intprefix.out: pnglibconf.h
+
+libpng.sym: scripts/sym.out
+	rm -f $@
+	cp $? $@
+libpng.vers: scripts/vers.out
+	rm -f $@
+	cp $? $@
+
+# Rename functions in scripts/prefix.out with a PNG_PREFIX prefix.
+# Rename macros in scripts/macro.lst from PNG_PREFIXpng_ to PNG_ (the actual
+# implementation of the macro).
+@DO_PNG_PREFIX_TRUE@pnglibconf.h: pnglibconf.out scripts/prefix.out scripts/macro.lst
+@DO_PNG_PREFIX_TRUE@	rm -f $@
+@DO_PNG_PREFIX_TRUE@	$(AWK) 's==0 && NR>1{print prev}\
+@DO_PNG_PREFIX_TRUE@	   s==0{prev=$$0}\
+@DO_PNG_PREFIX_TRUE@	   s==1{print "#define", $$1, "@PNG_PREFIX@" $$1}\
+@DO_PNG_PREFIX_TRUE@	   s==2{print "#define @PNG_PREFIX@png_" $$1, "PNG_" $$1}\
+@DO_PNG_PREFIX_TRUE@	   END{print prev}' s=0 pnglibconf.out s=1 scripts/prefix.out\
+@DO_PNG_PREFIX_TRUE@	   s=2 ${srcdir}/scripts/macro.lst >pnglibconf.tf8
+@DO_PNG_PREFIX_TRUE@	mv pnglibconf.tf8 $@
+
+@DO_PNG_PREFIX_TRUE@pngprefix.h: scripts/intprefix.out
+@DO_PNG_PREFIX_TRUE@	rm -f pngprefix.tf1
+@DO_PNG_PREFIX_TRUE@	$(AWK) '{print "#define", $$1, "@PNG_PREFIX@" $$1}' $? >pngprefix.tf1
+@DO_PNG_PREFIX_TRUE@	mv pngprefix.tf1 $@
+@DO_PNG_PREFIX_FALSE@pnglibconf.h: pnglibconf.out
+@DO_PNG_PREFIX_FALSE@	rm -f $@
+@DO_PNG_PREFIX_FALSE@	cp $? $@
+
+@DO_PNG_PREFIX_FALSE@pngprefix.h: # is empty
+@DO_PNG_PREFIX_FALSE@	:>$@
+
+$(srcdir)/scripts/pnglibconf.h.prebuilt:
+	@echo "Attempting to build $@" >&2
+	@echo "This is a machine generated file, but if you want to make" >&2
+	@echo "a new one simply make 'scripts/pnglibconf.out', copy that" >&2
+	@echo "AND set PNG_ZLIB_VERNUM to 0 (you MUST do this)" >&2
+	@exit 1
+
+# The following is necessary to ensure that the local pnglibconf.h is used, not
+# an installed one (this can happen immediately after on a clean system if
+# 'make test' is the first thing the user does.)  Only files which include
+# one of the png source files (typically png.h or pngpriv.h) need to be listed
+# here:
+pngtest.o: pnglibconf.h
+
+contrib/libtests/makepng.o: pnglibconf.h
+contrib/libtests/pngstest.o: pnglibconf.h
+contrib/libtests/pngunknown.o: pnglibconf.h
+contrib/libtests/pngimage.o: pnglibconf.h
+contrib/libtests/pngvalid.o: pnglibconf.h
+contrib/libtests/readpng.o: pnglibconf.h
+contrib/libtests/tarith.o: pnglibconf.h
+contrib/libtests/timepng.o: pnglibconf.h
+
+contrib/tools/makesRGB.o: pnglibconf.h
+contrib/tools/pngfix.o: pnglibconf.h
+contrib/tools/pngcp.o: pnglibconf.h
+
+.c.out:
+	rm -f $@ $*.tf[12]
+	test -d scripts || mkdir scripts || test -d scripts
+	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES)\
+	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $< > $*.tf1
+	$(AWK) -f "${srcdir}/scripts/dfn.awk" out="$*.tf2" $*.tf1 1>&2
+	rm -f $*.tf1
+	mv $*.tf2 $@
+
+# The .c file for pnglibconf.h is machine generated
+pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+	rm -f $@ $*.tf[45]
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf4 version=search\
+	    ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+	    ${srcdir}/pngusr.dfa $(DFA_XTRA) 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf5 $*.tf4 1>&2
+	rm $*.tf4
+	mv $*.tf5 $@
+
+# Symbol checks (.def and .out files should match)
+scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.out
+
+.out.chk:
+	rm -f $@ $*.new
+	$(AWK) -f ${srcdir}/scripts/checksym.awk ${srcdir}/scripts/${*F}.def\
+	    of="$*.new" $< >&2
+	mv $*.new $@
+
+# used on demand to regenerate the standard header, CPPFLAGS should
+# be empty - no non-standard defines
+scripts/pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
+	rm -f $@ pnglibconf.tf[67]
+	test -z "$(CPPFLAGS)"
+	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf6\
+	    logunsupported=1 version=search ${srcdir}/pngconf.h -\
+	    ${srcdir}/scripts/pnglibconf.dfa 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf7\
+	    pnglibconf.tf6 1>&2
+	rm pnglibconf.tf6
+	mv pnglibconf.tf7 $@
+
+$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS): png.h pngconf.h \
+	pnglibconf.h pngpriv.h pngdebug.h pnginfo.h pngstruct.h pngprefix.h
+
+test: check-am
+
+# Extra checks
+check: scripts/symbols.chk
+
+# Don't distribute the generated script files
+dist-hook:
+	cd '$(top_distdir)'; rm -f $(SCRIPT_CLEANFILES)
+
+# Make links between installed files with release-specific names and the generic
+# file names.  If this install rule is run the generic names will be deleted and
+# recreated - this has obvious issues for systems with multiple installations.
+
+install-header-links:
+	@set -ex; cd '$(DESTDIR)$(includedir)'; for f in $(HEADERS); do \
+	   rm -f "$$f"; $(LN_S) "$(PNGLIB_BASENAME)/$$f" "$$f"; done
+
+uninstall-header-links:
+	cd '$(DESTDIR)$(includedir)'; rm -f $(HEADERS)
+
+install-libpng-pc:
+	@set -ex; cd '$(DESTDIR)$(pkgconfigdir)'; rm -f libpng.pc; \
+	   $(LN_S) '$(PNGLIB_BASENAME).pc' libpng.pc
+
+uninstall-libpng-pc:
+	rm -f '$(DESTDIR)$(pkgconfigdir)/libpng.pc'
+
+install-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)';\
+	for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext";\
+           if test -f "$(PNGLIB_BASENAME).$$ext"; then\
+              $(LN_S) "$(PNGLIB_BASENAME).$$ext" "libpng.$$ext" || exit 1;\
+           fi;\
+	done
+
+uninstall-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)'; for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext"; done
+
+install-libpng-config:
+	@set -ex; cd '$(DESTDIR)$(bindir)'; rm -f libpng-config; \
+	   $(LN_S) '$(PNGLIB_BASENAME)-config' libpng-config
+
+uninstall-libpng-config:
+	rm -f '$(DESTDIR)$(bindir)/libpng-config'
+
+# If --enable-unversioned-links is specified the header and lib file links
+# will be automatically made on a 'make install':
+
+@DO_INSTALL_LINKS_TRUE@install-data-hook: install-header-links
+@DO_INSTALL_LINKS_TRUE@uninstall-hook: uninstall-header-links
+@DO_INSTALL_LINKS_TRUE@install-exec-hook: install-library-links
+@DO_INSTALL_LINKS_TRUE@uninstall-hook: uninstall-library-links
+
+# Likewise, --install-pc causes libpng.pc to be constructed:
+
+@DO_INSTALL_LIBPNG_PC_TRUE@install-data-hook: install-libpng-pc
+@DO_INSTALL_LIBPNG_PC_TRUE@uninstall-hook: uninstall-libpng-pc
+
+# And --install-config:
+
+@DO_INSTALL_LIBPNG_CONFIG_TRUE@install-exec-hook: install-libpng-config
+@DO_INSTALL_LIBPNG_CONFIG_TRUE@uninstall-hook: uninstall-libpng-config
+
+# The following addition ensures that 'make all' always builds the test programs
+# too.  It used to, but some change either in libpng or configure stopped this
+# working.
+all-am: $(check_PROGRAMS)
+
+# Tell versions [3.59,3.63) of GNU make to not export all variables.
+# Otherwise a system limit (for SysV at least) may be exceeded.
+.NOEXPORT:
diff --git a/extern/libpng/README b/extern/libpng/README
new file mode 100644
index 0000000000..cfc1f0e3dc
--- /dev/null
+++ b/extern/libpng/README
@@ -0,0 +1,183 @@
+README for libpng version 1.6.37 - April 14, 2019
+=================================================
+
+See the note about version numbers near the top of png.h.
+See INSTALL for instructions on how to install libpng.
+
+Libpng comes in several distribution formats.  Get libpng-*.tar.gz or
+libpng-*.tar.xz or if you want UNIX-style line endings in the text
+files, or lpng*.7z or lpng*.zip if you want DOS-style line endings.
+
+Version 0.89 was the first official release of libpng.  Don't let the
+fact that it's the first release fool you.  The libpng library has been
+in extensive use and testing since mid-1995.  By late 1997 it had
+finally gotten to the stage where there hadn't been significant
+changes to the API in some time, and people have a bad feeling about
+libraries with versions < 1.0.  Version 1.0.0 was released in
+March 1998.
+
+****
+Note that some of the changes to the png_info structure render this
+version of the library binary incompatible with libpng-0.89 or
+earlier versions if you are using a shared library.  The type of the
+"filler" parameter for png_set_filler() has changed from png_byte to
+png_uint_32, which will affect shared-library applications that use
+this function.
+
+To avoid problems with changes to the internals of the png info_struct,
+new APIs have been made available in 0.95 to avoid direct application
+access to info_ptr.  These functions are the png_set_<chunk> and
+png_get_<chunk> functions.  These functions should be used when
+accessing/storing the info_struct data, rather than manipulating it
+directly, to avoid such problems in the future.
+
+It is important to note that the APIs did not make current programs
+that access the info struct directly incompatible with the new
+library, through libpng-1.2.x.  In libpng-1.4.x, which was meant to
+be a transitional release, members of the png_struct and the
+info_struct can still be accessed, but the compiler will issue a
+warning about deprecated usage.  Since libpng-1.5.0, direct access
+to these structs is not allowed, and the definitions of the structs
+reside in private pngstruct.h and pnginfo.h header files that are not
+accessible to applications.  It is strongly suggested that new
+programs use the new APIs (as shown in example.c and pngtest.c), and
+older programs be converted to the new format, to facilitate upgrades
+in the future.
+****
+
+Additions since 0.90 include the ability to compile libpng as a
+Windows DLL, and new APIs for accessing data in the info struct.
+Experimental functions include the ability to set weighting and cost
+factors for row filter selection, direct reads of integers from buffers
+on big-endian processors that support misaligned data access, faster
+methods of doing alpha composition, and more accurate 16->8 bit color
+conversion.
+
+The additions since 0.89 include the ability to read from a PNG stream
+which has had some (or all) of the signature bytes read by the calling
+application.  This also allows the reading of embedded PNG streams that
+do not have the PNG file signature.  As well, it is now possible to set
+the library action on the detection of chunk CRC errors.  It is possible
+to set different actions based on whether the CRC error occurred in a
+critical or an ancillary chunk.
+
+For a detailed description on using libpng, read libpng-manual.txt.
+For examples of libpng in a program, see example.c and pngtest.c.  For
+usage information and restrictions (what little they are) on libpng,
+see png.h.  For a description on using zlib (the compression library
+used by libpng) and zlib's restrictions, see zlib.h
+
+I have included a general makefile, as well as several machine and
+compiler specific ones, but you may have to modify one for your own
+needs.
+
+You should use zlib 1.0.4 or later to run this, but it MAY work with
+versions as old as zlib 0.95.  Even so, there are bugs in older zlib
+versions which can cause the output of invalid compression streams for
+some images.
+
+You should also note that zlib is a compression library that is useful
+for more things than just PNG files.  You can use zlib as a drop-in
+replacement for fread() and fwrite(), if you are so inclined.
+
+zlib should be available at the same place that libpng is, or at
+https://zlib.net.
+
+You may also want a copy of the PNG specification.  It is available
+as an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find
+these at http://www.libpng.org/pub/png/pngdocs.html .
+
+This code is currently being archived at libpng.sourceforge.io in the
+[DOWNLOAD] area, and at http://libpng.download/src .
+
+This release, based in a large way on Glenn's, Guy's and Andreas'
+earlier work, was created and will be supported by myself and the PNG
+development group.
+
+Send comments/corrections/commendations to png-mng-implement at
+lists.sourceforge.net (subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe).
+
+Send general questions about the PNG specification to png-mng-misc
+at lists.sourceforge.net (subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-misc to
+subscribe).
+
+Files in this distribution:
+
+      ANNOUNCE      =>  Announcement of this version, with recent changes
+      AUTHORS       =>  List of contributing authors
+      CHANGES       =>  Description of changes between libpng versions
+      KNOWNBUG      =>  List of known bugs and deficiencies
+      LICENSE       =>  License to use and redistribute libpng
+      README        =>  This file
+      TODO          =>  Things not implemented in the current library
+      TRADEMARK     =>  Trademark information
+      example.c     =>  Example code for using libpng functions
+      libpng.3      =>  manual page for libpng (includes libpng-manual.txt)
+      libpng-manual.txt  =>  Description of libpng and its functions
+      libpngpf.3    =>  manual page for libpng's private functions
+      png.5         =>  manual page for the PNG format
+      png.c         =>  Basic interface functions common to library
+      png.h         =>  Library function and interface declarations (public)
+      pngpriv.h     =>  Library function and interface declarations (private)
+      pngconf.h     =>  System specific library configuration (public)
+      pngstruct.h   =>  png_struct declaration (private)
+      pnginfo.h     =>  png_info struct declaration (private)
+      pngdebug.h    =>  debugging macros (private)
+      pngerror.c    =>  Error/warning message I/O functions
+      pngget.c      =>  Functions for retrieving info from struct
+      pngmem.c      =>  Memory handling functions
+      pngbar.png    =>  PNG logo, 88x31
+      pngnow.png    =>  PNG logo, 98x31
+      pngpread.c    =>  Progressive reading functions
+      pngread.c     =>  Read data/helper high-level functions
+      pngrio.c      =>  Lowest-level data read I/O functions
+      pngrtran.c    =>  Read data transformation functions
+      pngrutil.c    =>  Read data utility functions
+      pngset.c      =>  Functions for storing data into the info_struct
+      pngtest.c     =>  Library test program
+      pngtest.png   =>  Library test sample image
+      pngtrans.c    =>  Common data transformation functions
+      pngwio.c      =>  Lowest-level write I/O functions
+      pngwrite.c    =>  High-level write functions
+      pngwtran.c    =>  Write data transformations
+      pngwutil.c    =>  Write utility functions
+      arm           =>  Contains optimized code for the ARM platform
+      powerpc       =>  Contains optimized code for the PowerPC platform
+      contrib       =>  Contributions
+       arm-neon         =>  Optimized code for ARM-NEON platform
+       powerpc-vsx      =>  Optimized code for POWERPC-VSX platform
+       examples         =>  Example programs
+       gregbook         =>  source code for PNG reading and writing, from
+                            Greg Roelofs' "PNG: The Definitive Guide",
+                            O'Reilly, 1999
+       libtests         =>  Test programs
+       mips-msa         =>  Optimized code for MIPS-MSA platform
+       pngminim         =>  Minimal decoder, encoder, and progressive decoder
+                            programs demonstrating use of pngusr.dfa
+       pngminus         =>  Simple pnm2png and png2pnm programs
+       pngsuite         =>  Test images
+       testpngs
+       tools            =>  Various tools
+       visupng          =>  Contains a MSVC workspace for VisualPng
+      intel             =>  Optimized code for INTEL-SSE2 platform
+      mips              =>  Optimized code for MIPS platform
+      projects      =>  Contains project files and workspaces for
+                        building a DLL
+       owatcom          =>  Contains a WATCOM project for building libpng
+       visualc71        =>  Contains a Microsoft Visual C++ (MSVC)
+                            workspace for building libpng and zlib
+       vstudio          =>  Contains a Microsoft Visual C++ (MSVC)
+                            workspace for building libpng and zlib
+      scripts       =>  Directory containing scripts for building libpng:
+                            (see scripts/README.txt for the list of scripts)
+
+Good luck, and happy coding!
+
+ * Cosmin Truta (current maintainer, since 2018)
+ * Glenn Randers-Pehrson (former maintainer, 1998-2018)
+ * Andreas Eric Dilger (former maintainer, 1996-1997)
+ * Guy Eric Schalnat (original author and former maintainer, 1995-1996)
+   (formerly of Group 42, Inc.)
diff --git a/extern/libpng/TODO b/extern/libpng/TODO
new file mode 100644
index 0000000000..562dab0696
--- /dev/null
+++ b/extern/libpng/TODO
@@ -0,0 +1,23 @@
+TODO - list of things to do for libpng:
+
+* Fix all defects (duh!)
+* Better C++ wrapper / full C++ implementation (?)
+* Fix the problems with C++ and 'extern "C"'.
+* cHRM transformation.
+* Palette creation.
+* "grayscale->palette" transformation and "palette->grayscale" detection.
+* Improved dithering.
+* Multi-lingual error and warning message support.
+* Complete sRGB transformation.  (Currently it simply uses gamma=0.45455.)
+* Man pages for function calls.
+* Better documentation.
+* Better filter selection
+  (e.g., counting huffman bits/precompression; filter inertia; filter costs).
+* Histogram creation.
+* Text conversion between different code pages (e.g., Latin-1 -> Mac).
+* Avoid building gamma tables whenever possible.
+* Greater precision in changing to linear gamma for compositing against
+  background, and in doing rgb-to-gray transformations.
+* Investigate pre-incremented loop counters and other loop constructions.
+* Interpolated method of handling interlacing.
+* More validations for libpng transformations.
diff --git a/extern/libpng/TRADEMARK b/extern/libpng/TRADEMARK
new file mode 100644
index 0000000000..ac667187d6
--- /dev/null
+++ b/extern/libpng/TRADEMARK
@@ -0,0 +1,8 @@
+TRADEMARK
+=========
+
+The name "libpng" has not been registered by the Copyright owners
+as a trademark in any jurisdiction.  However, because libpng has
+been distributed and maintained world-wide, continually since 1995,
+the Copyright owners claim "common-law trademark protection" in any
+jurisdiction where common-law trademark is recognized.
diff --git a/extern/libpng/aclocal.m4 b/extern/libpng/aclocal.m4
new file mode 100644
index 0000000000..bc18c34f01
--- /dev/null
+++ b/extern/libpng/aclocal.m4
@@ -0,0 +1,1196 @@
+# generated automatically by aclocal 1.16.1 -*- Autoconf -*-
+
+# Copyright (C) 1996-2018 Free Software Foundation, Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY, to the extent permitted by law; without
+# even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE.
+
+m4_ifndef([AC_CONFIG_MACRO_DIRS], [m4_defun([_AM_CONFIG_MACRO_DIRS], [])m4_defun([AC_CONFIG_MACRO_DIRS], [_AM_CONFIG_MACRO_DIRS($@)])])
+m4_ifndef([AC_AUTOCONF_VERSION],
+  [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
+m4_if(m4_defn([AC_AUTOCONF_VERSION]), [2.69],,
+[m4_warning([this file was generated for autoconf 2.69.
+You have another version of autoconf.  It may work, but is not guaranteed to.
+If you have problems, you may need to regenerate the build system entirely.
+To do so, use the procedure documented by the package, typically 'autoreconf'.])])
+
+# Copyright (C) 2002-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_AUTOMAKE_VERSION(VERSION)
+# ----------------------------
+# Automake X.Y traces this macro to ensure aclocal.m4 has been
+# generated from the m4 files accompanying Automake X.Y.
+# (This private macro should not be called outside this file.)
+AC_DEFUN([AM_AUTOMAKE_VERSION],
+[am__api_version='1.16'
+dnl Some users find AM_AUTOMAKE_VERSION and mistake it for a way to
+dnl require some minimum version.  Point them to the right macro.
+m4_if([$1], [1.16.1], [],
+      [AC_FATAL([Do not call $0, use AM_INIT_AUTOMAKE([$1]).])])dnl
+])
+
+# _AM_AUTOCONF_VERSION(VERSION)
+# -----------------------------
+# aclocal traces this macro to find the Autoconf version.
+# This is a private macro too.  Using m4_define simplifies
+# the logic in aclocal, which can simply ignore this definition.
+m4_define([_AM_AUTOCONF_VERSION], [])
+
+# AM_SET_CURRENT_AUTOMAKE_VERSION
+# -------------------------------
+# Call AM_AUTOMAKE_VERSION and AM_AUTOMAKE_VERSION so they can be traced.
+# This function is AC_REQUIREd by AM_INIT_AUTOMAKE.
+AC_DEFUN([AM_SET_CURRENT_AUTOMAKE_VERSION],
+[AM_AUTOMAKE_VERSION([1.16.1])dnl
+m4_ifndef([AC_AUTOCONF_VERSION],
+  [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
+_AM_AUTOCONF_VERSION(m4_defn([AC_AUTOCONF_VERSION]))])
+
+# Figure out how to run the assembler.                      -*- Autoconf -*-
+
+# Copyright (C) 2001-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_PROG_AS
+# ----------
+AC_DEFUN([AM_PROG_AS],
+[# By default we simply use the C compiler to build assembly code.
+AC_REQUIRE([AC_PROG_CC])
+test "${CCAS+set}" = set || CCAS=$CC
+test "${CCASFLAGS+set}" = set || CCASFLAGS=$CFLAGS
+AC_ARG_VAR([CCAS],      [assembler compiler command (defaults to CC)])
+AC_ARG_VAR([CCASFLAGS], [assembler compiler flags (defaults to CFLAGS)])
+_AM_IF_OPTION([no-dependencies],, [_AM_DEPENDENCIES([CCAS])])dnl
+])
+
+# AM_AUX_DIR_EXPAND                                         -*- Autoconf -*-
+
+# Copyright (C) 2001-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# For projects using AC_CONFIG_AUX_DIR([foo]), Autoconf sets
+# $ac_aux_dir to '$srcdir/foo'.  In other projects, it is set to
+# '$srcdir', '$srcdir/..', or '$srcdir/../..'.
+#
+# Of course, Automake must honor this variable whenever it calls a
+# tool from the auxiliary directory.  The problem is that $srcdir (and
+# therefore $ac_aux_dir as well) can be either absolute or relative,
+# depending on how configure is run.  This is pretty annoying, since
+# it makes $ac_aux_dir quite unusable in subdirectories: in the top
+# source directory, any form will work fine, but in subdirectories a
+# relative path needs to be adjusted first.
+#
+# $ac_aux_dir/missing
+#    fails when called from a subdirectory if $ac_aux_dir is relative
+# $top_srcdir/$ac_aux_dir/missing
+#    fails if $ac_aux_dir is absolute,
+#    fails when called from a subdirectory in a VPATH build with
+#          a relative $ac_aux_dir
+#
+# The reason of the latter failure is that $top_srcdir and $ac_aux_dir
+# are both prefixed by $srcdir.  In an in-source build this is usually
+# harmless because $srcdir is '.', but things will broke when you
+# start a VPATH build or use an absolute $srcdir.
+#
+# So we could use something similar to $top_srcdir/$ac_aux_dir/missing,
+# iff we strip the leading $srcdir from $ac_aux_dir.  That would be:
+#   am_aux_dir='\$(top_srcdir)/'`expr "$ac_aux_dir" : "$srcdir//*\(.*\)"`
+# and then we would define $MISSING as
+#   MISSING="\${SHELL} $am_aux_dir/missing"
+# This will work as long as MISSING is not called from configure, because
+# unfortunately $(top_srcdir) has no meaning in configure.
+# However there are other variables, like CC, which are often used in
+# configure, and could therefore not use this "fixed" $ac_aux_dir.
+#
+# Another solution, used here, is to always expand $ac_aux_dir to an
+# absolute PATH.  The drawback is that using absolute paths prevent a
+# configured tree to be moved without reconfiguration.
+
+AC_DEFUN([AM_AUX_DIR_EXPAND],
+[AC_REQUIRE([AC_CONFIG_AUX_DIR_DEFAULT])dnl
+# Expand $ac_aux_dir to an absolute path.
+am_aux_dir=`cd "$ac_aux_dir" && pwd`
+])
+
+# AM_CONDITIONAL                                            -*- Autoconf -*-
+
+# Copyright (C) 1997-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_CONDITIONAL(NAME, SHELL-CONDITION)
+# -------------------------------------
+# Define a conditional.
+AC_DEFUN([AM_CONDITIONAL],
+[AC_PREREQ([2.52])dnl
+ m4_if([$1], [TRUE],  [AC_FATAL([$0: invalid condition: $1])],
+       [$1], [FALSE], [AC_FATAL([$0: invalid condition: $1])])dnl
+AC_SUBST([$1_TRUE])dnl
+AC_SUBST([$1_FALSE])dnl
+_AM_SUBST_NOTMAKE([$1_TRUE])dnl
+_AM_SUBST_NOTMAKE([$1_FALSE])dnl
+m4_define([_AM_COND_VALUE_$1], [$2])dnl
+if $2; then
+  $1_TRUE=
+  $1_FALSE='#'
+else
+  $1_TRUE='#'
+  $1_FALSE=
+fi
+AC_CONFIG_COMMANDS_PRE(
+[if test -z "${$1_TRUE}" && test -z "${$1_FALSE}"; then
+  AC_MSG_ERROR([[conditional "$1" was never defined.
+Usually this means the macro was only invoked conditionally.]])
+fi])])
+
+# Copyright (C) 1999-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+
+# There are a few dirty hacks below to avoid letting 'AC_PROG_CC' be
+# written in clear, in which case automake, when reading aclocal.m4,
+# will think it sees a *use*, and therefore will trigger all it's
+# C support machinery.  Also note that it means that autoscan, seeing
+# CC etc. in the Makefile, will ask for an AC_PROG_CC use...
+
+
+# _AM_DEPENDENCIES(NAME)
+# ----------------------
+# See how the compiler implements dependency checking.
+# NAME is "CC", "CXX", "OBJC", "OBJCXX", "UPC", or "GJC".
+# We try a few techniques and use that to set a single cache variable.
+#
+# We don't AC_REQUIRE the corresponding AC_PROG_CC since the latter was
+# modified to invoke _AM_DEPENDENCIES(CC); we would have a circular
+# dependency, and given that the user is not expected to run this macro,
+# just rely on AC_PROG_CC.
+AC_DEFUN([_AM_DEPENDENCIES],
+[AC_REQUIRE([AM_SET_DEPDIR])dnl
+AC_REQUIRE([AM_OUTPUT_DEPENDENCY_COMMANDS])dnl
+AC_REQUIRE([AM_MAKE_INCLUDE])dnl
+AC_REQUIRE([AM_DEP_TRACK])dnl
+
+m4_if([$1], [CC],   [depcc="$CC"   am_compiler_list=],
+      [$1], [CXX],  [depcc="$CXX"  am_compiler_list=],
+      [$1], [OBJC], [depcc="$OBJC" am_compiler_list='gcc3 gcc'],
+      [$1], [OBJCXX], [depcc="$OBJCXX" am_compiler_list='gcc3 gcc'],
+      [$1], [UPC],  [depcc="$UPC"  am_compiler_list=],
+      [$1], [GCJ],  [depcc="$GCJ"  am_compiler_list='gcc3 gcc'],
+                    [depcc="$$1"   am_compiler_list=])
+
+AC_CACHE_CHECK([dependency style of $depcc],
+               [am_cv_$1_dependencies_compiler_type],
+[if test -z "$AMDEP_TRUE" && test -f "$am_depcomp"; then
+  # We make a subdir and do the tests there.  Otherwise we can end up
+  # making bogus files that we don't know about and never remove.  For
+  # instance it was reported that on HP-UX the gcc test will end up
+  # making a dummy file named 'D' -- because '-MD' means "put the output
+  # in D".
+  rm -rf conftest.dir
+  mkdir conftest.dir
+  # Copy depcomp to subdir because otherwise we won't find it if we're
+  # using a relative directory.
+  cp "$am_depcomp" conftest.dir
+  cd conftest.dir
+  # We will build objects and dependencies in a subdirectory because
+  # it helps to detect inapplicable dependency modes.  For instance
+  # both Tru64's cc and ICC support -MD to output dependencies as a
+  # side effect of compilation, but ICC will put the dependencies in
+  # the current directory while Tru64 will put them in the object
+  # directory.
+  mkdir sub
+
+  am_cv_$1_dependencies_compiler_type=none
+  if test "$am_compiler_list" = ""; then
+     am_compiler_list=`sed -n ['s/^#*\([a-zA-Z0-9]*\))$/\1/p'] < ./depcomp`
+  fi
+  am__universal=false
+  m4_case([$1], [CC],
+    [case " $depcc " in #(
+     *\ -arch\ *\ -arch\ *) am__universal=true ;;
+     esac],
+    [CXX],
+    [case " $depcc " in #(
+     *\ -arch\ *\ -arch\ *) am__universal=true ;;
+     esac])
+
+  for depmode in $am_compiler_list; do
+    # Setup a source with many dependencies, because some compilers
+    # like to wrap large dependency lists on column 80 (with \), and
+    # we should not choose a depcomp mode which is confused by this.
+    #
+    # We need to recreate these files for each test, as the compiler may
+    # overwrite some of them when testing with obscure command lines.
+    # This happens at least with the AIX C compiler.
+    : > sub/conftest.c
+    for i in 1 2 3 4 5 6; do
+      echo '#include "conftst'$i'.h"' >> sub/conftest.c
+      # Using ": > sub/conftst$i.h" creates only sub/conftst1.h with
+      # Solaris 10 /bin/sh.
+      echo '/* dummy */' > sub/conftst$i.h
+    done
+    echo "${am__include} ${am__quote}sub/conftest.Po${am__quote}" > confmf
+
+    # We check with '-c' and '-o' for the sake of the "dashmstdout"
+    # mode.  It turns out that the SunPro C++ compiler does not properly
+    # handle '-M -o', and we need to detect this.  Also, some Intel
+    # versions had trouble with output in subdirs.
+    am__obj=sub/conftest.${OBJEXT-o}
+    am__minus_obj="-o $am__obj"
+    case $depmode in
+    gcc)
+      # This depmode causes a compiler race in universal mode.
+      test "$am__universal" = false || continue
+      ;;
+    nosideeffect)
+      # After this tag, mechanisms are not by side-effect, so they'll
+      # only be used when explicitly requested.
+      if test "x$enable_dependency_tracking" = xyes; then
+	continue
+      else
+	break
+      fi
+      ;;
+    msvc7 | msvc7msys | msvisualcpp | msvcmsys)
+      # This compiler won't grok '-c -o', but also, the minuso test has
+      # not run yet.  These depmodes are late enough in the game, and
+      # so weak that their functioning should not be impacted.
+      am__obj=conftest.${OBJEXT-o}
+      am__minus_obj=
+      ;;
+    none) break ;;
+    esac
+    if depmode=$depmode \
+       source=sub/conftest.c object=$am__obj \
+       depfile=sub/conftest.Po tmpdepfile=sub/conftest.TPo \
+       $SHELL ./depcomp $depcc -c $am__minus_obj sub/conftest.c \
+         >/dev/null 2>conftest.err &&
+       grep sub/conftst1.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep sub/conftst6.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep $am__obj sub/conftest.Po > /dev/null 2>&1 &&
+       ${MAKE-make} -s -f confmf > /dev/null 2>&1; then
+      # icc doesn't choke on unknown options, it will just issue warnings
+      # or remarks (even with -Werror).  So we grep stderr for any message
+      # that says an option was ignored or not supported.
+      # When given -MP, icc 7.0 and 7.1 complain thusly:
+      #   icc: Command line warning: ignoring option '-M'; no argument required
+      # The diagnosis changed in icc 8.0:
+      #   icc: Command line remark: option '-MP' not supported
+      if (grep 'ignoring option' conftest.err ||
+          grep 'not supported' conftest.err) >/dev/null 2>&1; then :; else
+        am_cv_$1_dependencies_compiler_type=$depmode
+        break
+      fi
+    fi
+  done
+
+  cd ..
+  rm -rf conftest.dir
+else
+  am_cv_$1_dependencies_compiler_type=none
+fi
+])
+AC_SUBST([$1DEPMODE], [depmode=$am_cv_$1_dependencies_compiler_type])
+AM_CONDITIONAL([am__fastdep$1], [
+  test "x$enable_dependency_tracking" != xno \
+  && test "$am_cv_$1_dependencies_compiler_type" = gcc3])
+])
+
+
+# AM_SET_DEPDIR
+# -------------
+# Choose a directory name for dependency files.
+# This macro is AC_REQUIREd in _AM_DEPENDENCIES.
+AC_DEFUN([AM_SET_DEPDIR],
+[AC_REQUIRE([AM_SET_LEADING_DOT])dnl
+AC_SUBST([DEPDIR], ["${am__leading_dot}deps"])dnl
+])
+
+
+# AM_DEP_TRACK
+# ------------
+AC_DEFUN([AM_DEP_TRACK],
+[AC_ARG_ENABLE([dependency-tracking], [dnl
+AS_HELP_STRING(
+  [--enable-dependency-tracking],
+  [do not reject slow dependency extractors])
+AS_HELP_STRING(
+  [--disable-dependency-tracking],
+  [speeds up one-time build])])
+if test "x$enable_dependency_tracking" != xno; then
+  am_depcomp="$ac_aux_dir/depcomp"
+  AMDEPBACKSLASH='\'
+  am__nodep='_no'
+fi
+AM_CONDITIONAL([AMDEP], [test "x$enable_dependency_tracking" != xno])
+AC_SUBST([AMDEPBACKSLASH])dnl
+_AM_SUBST_NOTMAKE([AMDEPBACKSLASH])dnl
+AC_SUBST([am__nodep])dnl
+_AM_SUBST_NOTMAKE([am__nodep])dnl
+])
+
+# Generate code to set up dependency tracking.              -*- Autoconf -*-
+
+# Copyright (C) 1999-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_OUTPUT_DEPENDENCY_COMMANDS
+# ------------------------------
+AC_DEFUN([_AM_OUTPUT_DEPENDENCY_COMMANDS],
+[{
+  # Older Autoconf quotes --file arguments for eval, but not when files
+  # are listed without --file.  Let's play safe and only enable the eval
+  # if we detect the quoting.
+  # TODO: see whether this extra hack can be removed once we start
+  # requiring Autoconf 2.70 or later.
+  AS_CASE([$CONFIG_FILES],
+          [*\'*], [eval set x "$CONFIG_FILES"],
+          [*], [set x $CONFIG_FILES])
+  shift
+  # Used to flag and report bootstrapping failures.
+  am_rc=0
+  for am_mf
+  do
+    # Strip MF so we end up with the name of the file.
+    am_mf=`AS_ECHO(["$am_mf"]) | sed -e 's/:.*$//'`
+    # Check whether this is an Automake generated Makefile which includes
+    # dependency-tracking related rules and includes.
+    # Grep'ing the whole file directly is not great: AIX grep has a line
+    # limit of 2048, but all sed's we know have understand at least 4000.
+    sed -n 's,^am--depfiles:.*,X,p' "$am_mf" | grep X >/dev/null 2>&1 \
+      || continue
+    am_dirpart=`AS_DIRNAME(["$am_mf"])`
+    am_filepart=`AS_BASENAME(["$am_mf"])`
+    AM_RUN_LOG([cd "$am_dirpart" \
+      && sed -e '/# am--include-marker/d' "$am_filepart" \
+        | $MAKE -f - am--depfiles]) || am_rc=$?
+  done
+  if test $am_rc -ne 0; then
+    AC_MSG_FAILURE([Something went wrong bootstrapping makefile fragments
+    for automatic dependency tracking.  Try re-running configure with the
+    '--disable-dependency-tracking' option to at least be able to build
+    the package (albeit without support for automatic dependency tracking).])
+  fi
+  AS_UNSET([am_dirpart])
+  AS_UNSET([am_filepart])
+  AS_UNSET([am_mf])
+  AS_UNSET([am_rc])
+  rm -f conftest-deps.mk
+}
+])# _AM_OUTPUT_DEPENDENCY_COMMANDS
+
+
+# AM_OUTPUT_DEPENDENCY_COMMANDS
+# -----------------------------
+# This macro should only be invoked once -- use via AC_REQUIRE.
+#
+# This code is only required when automatic dependency tracking is enabled.
+# This creates each '.Po' and '.Plo' makefile fragment that we'll need in
+# order to bootstrap the dependency handling code.
+AC_DEFUN([AM_OUTPUT_DEPENDENCY_COMMANDS],
+[AC_CONFIG_COMMANDS([depfiles],
+     [test x"$AMDEP_TRUE" != x"" || _AM_OUTPUT_DEPENDENCY_COMMANDS],
+     [AMDEP_TRUE="$AMDEP_TRUE" MAKE="${MAKE-make}"])])
+
+# Do all the work for Automake.                             -*- Autoconf -*-
+
+# Copyright (C) 1996-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# This macro actually does too much.  Some checks are only needed if
+# your package does certain things.  But this isn't really a big deal.
+
+dnl Redefine AC_PROG_CC to automatically invoke _AM_PROG_CC_C_O.
+m4_define([AC_PROG_CC],
+m4_defn([AC_PROG_CC])
+[_AM_PROG_CC_C_O
+])
+
+# AM_INIT_AUTOMAKE(PACKAGE, VERSION, [NO-DEFINE])
+# AM_INIT_AUTOMAKE([OPTIONS])
+# -----------------------------------------------
+# The call with PACKAGE and VERSION arguments is the old style
+# call (pre autoconf-2.50), which is being phased out.  PACKAGE
+# and VERSION should now be passed to AC_INIT and removed from
+# the call to AM_INIT_AUTOMAKE.
+# We support both call styles for the transition.  After
+# the next Automake release, Autoconf can make the AC_INIT
+# arguments mandatory, and then we can depend on a new Autoconf
+# release and drop the old call support.
+AC_DEFUN([AM_INIT_AUTOMAKE],
+[AC_PREREQ([2.65])dnl
+dnl Autoconf wants to disallow AM_ names.  We explicitly allow
+dnl the ones we care about.
+m4_pattern_allow([^AM_[A-Z]+FLAGS$])dnl
+AC_REQUIRE([AM_SET_CURRENT_AUTOMAKE_VERSION])dnl
+AC_REQUIRE([AC_PROG_INSTALL])dnl
+if test "`cd $srcdir && pwd`" != "`pwd`"; then
+  # Use -I$(srcdir) only when $(srcdir) != ., so that make's output
+  # is not polluted with repeated "-I."
+  AC_SUBST([am__isrc], [' -I$(srcdir)'])_AM_SUBST_NOTMAKE([am__isrc])dnl
+  # test to see if srcdir already configured
+  if test -f $srcdir/config.status; then
+    AC_MSG_ERROR([source directory already configured; run "make distclean" there first])
+  fi
+fi
+
+# test whether we have cygpath
+if test -z "$CYGPATH_W"; then
+  if (cygpath --version) >/dev/null 2>/dev/null; then
+    CYGPATH_W='cygpath -w'
+  else
+    CYGPATH_W=echo
+  fi
+fi
+AC_SUBST([CYGPATH_W])
+
+# Define the identity of the package.
+dnl Distinguish between old-style and new-style calls.
+m4_ifval([$2],
+[AC_DIAGNOSE([obsolete],
+             [$0: two- and three-arguments forms are deprecated.])
+m4_ifval([$3], [_AM_SET_OPTION([no-define])])dnl
+ AC_SUBST([PACKAGE], [$1])dnl
+ AC_SUBST([VERSION], [$2])],
+[_AM_SET_OPTIONS([$1])dnl
+dnl Diagnose old-style AC_INIT with new-style AM_AUTOMAKE_INIT.
+m4_if(
+  m4_ifdef([AC_PACKAGE_NAME], [ok]):m4_ifdef([AC_PACKAGE_VERSION], [ok]),
+  [ok:ok],,
+  [m4_fatal([AC_INIT should be called with package and version arguments])])dnl
+ AC_SUBST([PACKAGE], ['AC_PACKAGE_TARNAME'])dnl
+ AC_SUBST([VERSION], ['AC_PACKAGE_VERSION'])])dnl
+
+_AM_IF_OPTION([no-define],,
+[AC_DEFINE_UNQUOTED([PACKAGE], ["$PACKAGE"], [Name of package])
+ AC_DEFINE_UNQUOTED([VERSION], ["$VERSION"], [Version number of package])])dnl
+
+# Some tools Automake needs.
+AC_REQUIRE([AM_SANITY_CHECK])dnl
+AC_REQUIRE([AC_ARG_PROGRAM])dnl
+AM_MISSING_PROG([ACLOCAL], [aclocal-${am__api_version}])
+AM_MISSING_PROG([AUTOCONF], [autoconf])
+AM_MISSING_PROG([AUTOMAKE], [automake-${am__api_version}])
+AM_MISSING_PROG([AUTOHEADER], [autoheader])
+AM_MISSING_PROG([MAKEINFO], [makeinfo])
+AC_REQUIRE([AM_PROG_INSTALL_SH])dnl
+AC_REQUIRE([AM_PROG_INSTALL_STRIP])dnl
+AC_REQUIRE([AC_PROG_MKDIR_P])dnl
+# For better backward compatibility.  To be removed once Automake 1.9.x
+# dies out for good.  For more background, see:
+# <https://lists.gnu.org/archive/html/automake/2012-07/msg00001.html>
+# <https://lists.gnu.org/archive/html/automake/2012-07/msg00014.html>
+AC_SUBST([mkdir_p], ['$(MKDIR_P)'])
+# We need awk for the "check" target (and possibly the TAP driver).  The
+# system "awk" is bad on some platforms.
+AC_REQUIRE([AC_PROG_AWK])dnl
+AC_REQUIRE([AC_PROG_MAKE_SET])dnl
+AC_REQUIRE([AM_SET_LEADING_DOT])dnl
+_AM_IF_OPTION([tar-ustar], [_AM_PROG_TAR([ustar])],
+	      [_AM_IF_OPTION([tar-pax], [_AM_PROG_TAR([pax])],
+			     [_AM_PROG_TAR([v7])])])
+_AM_IF_OPTION([no-dependencies],,
+[AC_PROVIDE_IFELSE([AC_PROG_CC],
+		  [_AM_DEPENDENCIES([CC])],
+		  [m4_define([AC_PROG_CC],
+			     m4_defn([AC_PROG_CC])[_AM_DEPENDENCIES([CC])])])dnl
+AC_PROVIDE_IFELSE([AC_PROG_CXX],
+		  [_AM_DEPENDENCIES([CXX])],
+		  [m4_define([AC_PROG_CXX],
+			     m4_defn([AC_PROG_CXX])[_AM_DEPENDENCIES([CXX])])])dnl
+AC_PROVIDE_IFELSE([AC_PROG_OBJC],
+		  [_AM_DEPENDENCIES([OBJC])],
+		  [m4_define([AC_PROG_OBJC],
+			     m4_defn([AC_PROG_OBJC])[_AM_DEPENDENCIES([OBJC])])])dnl
+AC_PROVIDE_IFELSE([AC_PROG_OBJCXX],
+		  [_AM_DEPENDENCIES([OBJCXX])],
+		  [m4_define([AC_PROG_OBJCXX],
+			     m4_defn([AC_PROG_OBJCXX])[_AM_DEPENDENCIES([OBJCXX])])])dnl
+])
+AC_REQUIRE([AM_SILENT_RULES])dnl
+dnl The testsuite driver may need to know about EXEEXT, so add the
+dnl 'am__EXEEXT' conditional if _AM_COMPILER_EXEEXT was seen.  This
+dnl macro is hooked onto _AC_COMPILER_EXEEXT early, see below.
+AC_CONFIG_COMMANDS_PRE(dnl
+[m4_provide_if([_AM_COMPILER_EXEEXT],
+  [AM_CONDITIONAL([am__EXEEXT], [test -n "$EXEEXT"])])])dnl
+
+# POSIX will say in a future version that running "rm -f" with no argument
+# is OK; and we want to be able to make that assumption in our Makefile
+# recipes.  So use an aggressive probe to check that the usage we want is
+# actually supported "in the wild" to an acceptable degree.
+# See automake bug#10828.
+# To make any issue more visible, cause the running configure to be aborted
+# by default if the 'rm' program in use doesn't match our expectations; the
+# user can still override this though.
+if rm -f && rm -fr && rm -rf; then : OK; else
+  cat >&2 <<'END'
+Oops!
+
+Your 'rm' program seems unable to run without file operands specified
+on the command line, even when the '-f' option is present.  This is contrary
+to the behaviour of most rm programs out there, and not conforming with
+the upcoming POSIX standard: <http://austingroupbugs.net/view.php?id=542>
+
+Please tell bug-automake@gnu.org about your system, including the value
+of your $PATH and any error possibly output before this message.  This
+can help us improve future automake versions.
+
+END
+  if test x"$ACCEPT_INFERIOR_RM_PROGRAM" = x"yes"; then
+    echo 'Configuration will proceed anyway, since you have set the' >&2
+    echo 'ACCEPT_INFERIOR_RM_PROGRAM variable to "yes"' >&2
+    echo >&2
+  else
+    cat >&2 <<'END'
+Aborting the configuration process, to ensure you take notice of the issue.
+
+You can download and install GNU coreutils to get an 'rm' implementation
+that behaves properly: <https://www.gnu.org/software/coreutils/>.
+
+If you want to complete the configuration process using your problematic
+'rm' anyway, export the environment variable ACCEPT_INFERIOR_RM_PROGRAM
+to "yes", and re-run configure.
+
+END
+    AC_MSG_ERROR([Your 'rm' program is bad, sorry.])
+  fi
+fi
+dnl The trailing newline in this macro's definition is deliberate, for
+dnl backward compatibility and to allow trailing 'dnl'-style comments
+dnl after the AM_INIT_AUTOMAKE invocation. See automake bug#16841.
+])
+
+dnl Hook into '_AC_COMPILER_EXEEXT' early to learn its expansion.  Do not
+dnl add the conditional right here, as _AC_COMPILER_EXEEXT may be further
+dnl mangled by Autoconf and run in a shell conditional statement.
+m4_define([_AC_COMPILER_EXEEXT],
+m4_defn([_AC_COMPILER_EXEEXT])[m4_provide([_AM_COMPILER_EXEEXT])])
+
+# When config.status generates a header, we must update the stamp-h file.
+# This file resides in the same directory as the config header
+# that is generated.  The stamp files are numbered to have different names.
+
+# Autoconf calls _AC_AM_CONFIG_HEADER_HOOK (when defined) in the
+# loop where config.status creates the headers, so we can generate
+# our stamp files there.
+AC_DEFUN([_AC_AM_CONFIG_HEADER_HOOK],
+[# Compute $1's index in $config_headers.
+_am_arg=$1
+_am_stamp_count=1
+for _am_header in $config_headers :; do
+  case $_am_header in
+    $_am_arg | $_am_arg:* )
+      break ;;
+    * )
+      _am_stamp_count=`expr $_am_stamp_count + 1` ;;
+  esac
+done
+echo "timestamp for $_am_arg" >`AS_DIRNAME(["$_am_arg"])`/stamp-h[]$_am_stamp_count])
+
+# Copyright (C) 2001-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_PROG_INSTALL_SH
+# ------------------
+# Define $install_sh.
+AC_DEFUN([AM_PROG_INSTALL_SH],
+[AC_REQUIRE([AM_AUX_DIR_EXPAND])dnl
+if test x"${install_sh+set}" != xset; then
+  case $am_aux_dir in
+  *\ * | *\	*)
+    install_sh="\${SHELL} '$am_aux_dir/install-sh'" ;;
+  *)
+    install_sh="\${SHELL} $am_aux_dir/install-sh"
+  esac
+fi
+AC_SUBST([install_sh])])
+
+# Copyright (C) 2003-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Check whether the underlying file-system supports filenames
+# with a leading dot.  For instance MS-DOS doesn't.
+AC_DEFUN([AM_SET_LEADING_DOT],
+[rm -rf .tst 2>/dev/null
+mkdir .tst 2>/dev/null
+if test -d .tst; then
+  am__leading_dot=.
+else
+  am__leading_dot=_
+fi
+rmdir .tst 2>/dev/null
+AC_SUBST([am__leading_dot])])
+
+# Add --enable-maintainer-mode option to configure.         -*- Autoconf -*-
+# From Jim Meyering
+
+# Copyright (C) 1996-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_MAINTAINER_MODE([DEFAULT-MODE])
+# ----------------------------------
+# Control maintainer-specific portions of Makefiles.
+# Default is to disable them, unless 'enable' is passed literally.
+# For symmetry, 'disable' may be passed as well.  Anyway, the user
+# can override the default with the --enable/--disable switch.
+AC_DEFUN([AM_MAINTAINER_MODE],
+[m4_case(m4_default([$1], [disable]),
+       [enable], [m4_define([am_maintainer_other], [disable])],
+       [disable], [m4_define([am_maintainer_other], [enable])],
+       [m4_define([am_maintainer_other], [enable])
+        m4_warn([syntax], [unexpected argument to AM@&t@_MAINTAINER_MODE: $1])])
+AC_MSG_CHECKING([whether to enable maintainer-specific portions of Makefiles])
+  dnl maintainer-mode's default is 'disable' unless 'enable' is passed
+  AC_ARG_ENABLE([maintainer-mode],
+    [AS_HELP_STRING([--]am_maintainer_other[-maintainer-mode],
+      am_maintainer_other[ make rules and dependencies not useful
+      (and sometimes confusing) to the casual installer])],
+    [USE_MAINTAINER_MODE=$enableval],
+    [USE_MAINTAINER_MODE=]m4_if(am_maintainer_other, [enable], [no], [yes]))
+  AC_MSG_RESULT([$USE_MAINTAINER_MODE])
+  AM_CONDITIONAL([MAINTAINER_MODE], [test $USE_MAINTAINER_MODE = yes])
+  MAINT=$MAINTAINER_MODE_TRUE
+  AC_SUBST([MAINT])dnl
+]
+)
+
+# Check to see how 'make' treats includes.	            -*- Autoconf -*-
+
+# Copyright (C) 2001-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_MAKE_INCLUDE()
+# -----------------
+# Check whether make has an 'include' directive that can support all
+# the idioms we need for our automatic dependency tracking code.
+AC_DEFUN([AM_MAKE_INCLUDE],
+[AC_MSG_CHECKING([whether ${MAKE-make} supports the include directive])
+cat > confinc.mk << 'END'
+am__doit:
+	@echo this is the am__doit target >confinc.out
+.PHONY: am__doit
+END
+am__include="#"
+am__quote=
+# BSD make does it like this.
+echo '.include "confinc.mk" # ignored' > confmf.BSD
+# Other make implementations (GNU, Solaris 10, AIX) do it like this.
+echo 'include confinc.mk # ignored' > confmf.GNU
+_am_result=no
+for s in GNU BSD; do
+  AM_RUN_LOG([${MAKE-make} -f confmf.$s && cat confinc.out])
+  AS_CASE([$?:`cat confinc.out 2>/dev/null`],
+      ['0:this is the am__doit target'],
+      [AS_CASE([$s],
+          [BSD], [am__include='.include' am__quote='"'],
+          [am__include='include' am__quote=''])])
+  if test "$am__include" != "#"; then
+    _am_result="yes ($s style)"
+    break
+  fi
+done
+rm -f confinc.* confmf.*
+AC_MSG_RESULT([${_am_result}])
+AC_SUBST([am__include])])
+AC_SUBST([am__quote])])
+
+# Fake the existence of programs that GNU maintainers use.  -*- Autoconf -*-
+
+# Copyright (C) 1997-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_MISSING_PROG(NAME, PROGRAM)
+# ------------------------------
+AC_DEFUN([AM_MISSING_PROG],
+[AC_REQUIRE([AM_MISSING_HAS_RUN])
+$1=${$1-"${am_missing_run}$2"}
+AC_SUBST($1)])
+
+# AM_MISSING_HAS_RUN
+# ------------------
+# Define MISSING if not defined so far and test if it is modern enough.
+# If it is, set am_missing_run to use it, otherwise, to nothing.
+AC_DEFUN([AM_MISSING_HAS_RUN],
+[AC_REQUIRE([AM_AUX_DIR_EXPAND])dnl
+AC_REQUIRE_AUX_FILE([missing])dnl
+if test x"${MISSING+set}" != xset; then
+  case $am_aux_dir in
+  *\ * | *\	*)
+    MISSING="\${SHELL} \"$am_aux_dir/missing\"" ;;
+  *)
+    MISSING="\${SHELL} $am_aux_dir/missing" ;;
+  esac
+fi
+# Use eval to expand $SHELL
+if eval "$MISSING --is-lightweight"; then
+  am_missing_run="$MISSING "
+else
+  am_missing_run=
+  AC_MSG_WARN(['missing' script is too old or missing])
+fi
+])
+
+# Helper functions for option handling.                     -*- Autoconf -*-
+
+# Copyright (C) 2001-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_MANGLE_OPTION(NAME)
+# -----------------------
+AC_DEFUN([_AM_MANGLE_OPTION],
+[[_AM_OPTION_]m4_bpatsubst($1, [[^a-zA-Z0-9_]], [_])])
+
+# _AM_SET_OPTION(NAME)
+# --------------------
+# Set option NAME.  Presently that only means defining a flag for this option.
+AC_DEFUN([_AM_SET_OPTION],
+[m4_define(_AM_MANGLE_OPTION([$1]), [1])])
+
+# _AM_SET_OPTIONS(OPTIONS)
+# ------------------------
+# OPTIONS is a space-separated list of Automake options.
+AC_DEFUN([_AM_SET_OPTIONS],
+[m4_foreach_w([_AM_Option], [$1], [_AM_SET_OPTION(_AM_Option)])])
+
+# _AM_IF_OPTION(OPTION, IF-SET, [IF-NOT-SET])
+# -------------------------------------------
+# Execute IF-SET if OPTION is set, IF-NOT-SET otherwise.
+AC_DEFUN([_AM_IF_OPTION],
+[m4_ifset(_AM_MANGLE_OPTION([$1]), [$2], [$3])])
+
+# Copyright (C) 1999-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_PROG_CC_C_O
+# ---------------
+# Like AC_PROG_CC_C_O, but changed for automake.  We rewrite AC_PROG_CC
+# to automatically call this.
+AC_DEFUN([_AM_PROG_CC_C_O],
+[AC_REQUIRE([AM_AUX_DIR_EXPAND])dnl
+AC_REQUIRE_AUX_FILE([compile])dnl
+AC_LANG_PUSH([C])dnl
+AC_CACHE_CHECK(
+  [whether $CC understands -c and -o together],
+  [am_cv_prog_cc_c_o],
+  [AC_LANG_CONFTEST([AC_LANG_PROGRAM([])])
+  # Make sure it works both with $CC and with simple cc.
+  # Following AC_PROG_CC_C_O, we do the test twice because some
+  # compilers refuse to overwrite an existing .o file with -o,
+  # though they will create one.
+  am_cv_prog_cc_c_o=yes
+  for am_i in 1 2; do
+    if AM_RUN_LOG([$CC -c conftest.$ac_ext -o conftest2.$ac_objext]) \
+         && test -f conftest2.$ac_objext; then
+      : OK
+    else
+      am_cv_prog_cc_c_o=no
+      break
+    fi
+  done
+  rm -f core conftest*
+  unset am_i])
+if test "$am_cv_prog_cc_c_o" != yes; then
+   # Losing compiler, so override with the script.
+   # FIXME: It is wrong to rewrite CC.
+   # But if we don't then we get into trouble of one sort or another.
+   # A longer-term fix would be to have automake use am__CC in this case,
+   # and then we could set am__CC="\$(top_srcdir)/compile \$(CC)"
+   CC="$am_aux_dir/compile $CC"
+fi
+AC_LANG_POP([C])])
+
+# For backward compatibility.
+AC_DEFUN_ONCE([AM_PROG_CC_C_O], [AC_REQUIRE([AC_PROG_CC])])
+
+# Copyright (C) 2001-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_RUN_LOG(COMMAND)
+# -------------------
+# Run COMMAND, save the exit status in ac_status, and log it.
+# (This has been adapted from Autoconf's _AC_RUN_LOG macro.)
+AC_DEFUN([AM_RUN_LOG],
+[{ echo "$as_me:$LINENO: $1" >&AS_MESSAGE_LOG_FD
+   ($1) >&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&AS_MESSAGE_LOG_FD
+   (exit $ac_status); }])
+
+# Check to make sure that the build environment is sane.    -*- Autoconf -*-
+
+# Copyright (C) 1996-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_SANITY_CHECK
+# ---------------
+AC_DEFUN([AM_SANITY_CHECK],
+[AC_MSG_CHECKING([whether build environment is sane])
+# Reject unsafe characters in $srcdir or the absolute working directory
+# name.  Accept space and tab only in the latter.
+am_lf='
+'
+case `pwd` in
+  *[[\\\"\#\$\&\'\`$am_lf]]*)
+    AC_MSG_ERROR([unsafe absolute working directory name]);;
+esac
+case $srcdir in
+  *[[\\\"\#\$\&\'\`$am_lf\ \	]]*)
+    AC_MSG_ERROR([unsafe srcdir value: '$srcdir']);;
+esac
+
+# Do 'set' in a subshell so we don't clobber the current shell's
+# arguments.  Must try -L first in case configure is actually a
+# symlink; some systems play weird games with the mod time of symlinks
+# (eg FreeBSD returns the mod time of the symlink's containing
+# directory).
+if (
+   am_has_slept=no
+   for am_try in 1 2; do
+     echo "timestamp, slept: $am_has_slept" > conftest.file
+     set X `ls -Lt "$srcdir/configure" conftest.file 2> /dev/null`
+     if test "$[*]" = "X"; then
+	# -L didn't work.
+	set X `ls -t "$srcdir/configure" conftest.file`
+     fi
+     if test "$[*]" != "X $srcdir/configure conftest.file" \
+	&& test "$[*]" != "X conftest.file $srcdir/configure"; then
+
+	# If neither matched, then we have a broken ls.  This can happen
+	# if, for instance, CONFIG_SHELL is bash and it inherits a
+	# broken ls alias from the environment.  This has actually
+	# happened.  Such a system could not be considered "sane".
+	AC_MSG_ERROR([ls -t appears to fail.  Make sure there is not a broken
+  alias in your environment])
+     fi
+     if test "$[2]" = conftest.file || test $am_try -eq 2; then
+       break
+     fi
+     # Just in case.
+     sleep 1
+     am_has_slept=yes
+   done
+   test "$[2]" = conftest.file
+   )
+then
+   # Ok.
+   :
+else
+   AC_MSG_ERROR([newly created file is older than distributed files!
+Check your system clock])
+fi
+AC_MSG_RESULT([yes])
+# If we didn't sleep, we still need to ensure time stamps of config.status and
+# generated files are strictly newer.
+am_sleep_pid=
+if grep 'slept: no' conftest.file >/dev/null 2>&1; then
+  ( sleep 1 ) &
+  am_sleep_pid=$!
+fi
+AC_CONFIG_COMMANDS_PRE(
+  [AC_MSG_CHECKING([that generated files are newer than configure])
+   if test -n "$am_sleep_pid"; then
+     # Hide warnings about reused PIDs.
+     wait $am_sleep_pid 2>/dev/null
+   fi
+   AC_MSG_RESULT([done])])
+rm -f conftest.file
+])
+
+# Copyright (C) 2009-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_SILENT_RULES([DEFAULT])
+# --------------------------
+# Enable less verbose build rules; with the default set to DEFAULT
+# ("yes" being less verbose, "no" or empty being verbose).
+AC_DEFUN([AM_SILENT_RULES],
+[AC_ARG_ENABLE([silent-rules], [dnl
+AS_HELP_STRING(
+  [--enable-silent-rules],
+  [less verbose build output (undo: "make V=1")])
+AS_HELP_STRING(
+  [--disable-silent-rules],
+  [verbose build output (undo: "make V=0")])dnl
+])
+case $enable_silent_rules in @%:@ (((
+  yes) AM_DEFAULT_VERBOSITY=0;;
+   no) AM_DEFAULT_VERBOSITY=1;;
+    *) AM_DEFAULT_VERBOSITY=m4_if([$1], [yes], [0], [1]);;
+esac
+dnl
+dnl A few 'make' implementations (e.g., NonStop OS and NextStep)
+dnl do not support nested variable expansions.
+dnl See automake bug#9928 and bug#10237.
+am_make=${MAKE-make}
+AC_CACHE_CHECK([whether $am_make supports nested variables],
+   [am_cv_make_support_nested_variables],
+   [if AS_ECHO([['TRUE=$(BAR$(V))
+BAR0=false
+BAR1=true
+V=1
+am__doit:
+	@$(TRUE)
+.PHONY: am__doit']]) | $am_make -f - >/dev/null 2>&1; then
+  am_cv_make_support_nested_variables=yes
+else
+  am_cv_make_support_nested_variables=no
+fi])
+if test $am_cv_make_support_nested_variables = yes; then
+  dnl Using '$V' instead of '$(V)' breaks IRIX make.
+  AM_V='$(V)'
+  AM_DEFAULT_V='$(AM_DEFAULT_VERBOSITY)'
+else
+  AM_V=$AM_DEFAULT_VERBOSITY
+  AM_DEFAULT_V=$AM_DEFAULT_VERBOSITY
+fi
+AC_SUBST([AM_V])dnl
+AM_SUBST_NOTMAKE([AM_V])dnl
+AC_SUBST([AM_DEFAULT_V])dnl
+AM_SUBST_NOTMAKE([AM_DEFAULT_V])dnl
+AC_SUBST([AM_DEFAULT_VERBOSITY])dnl
+AM_BACKSLASH='\'
+AC_SUBST([AM_BACKSLASH])dnl
+_AM_SUBST_NOTMAKE([AM_BACKSLASH])dnl
+])
+
+# Copyright (C) 2001-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_PROG_INSTALL_STRIP
+# ---------------------
+# One issue with vendor 'install' (even GNU) is that you can't
+# specify the program used to strip binaries.  This is especially
+# annoying in cross-compiling environments, where the build's strip
+# is unlikely to handle the host's binaries.
+# Fortunately install-sh will honor a STRIPPROG variable, so we
+# always use install-sh in "make install-strip", and initialize
+# STRIPPROG with the value of the STRIP variable (set by the user).
+AC_DEFUN([AM_PROG_INSTALL_STRIP],
+[AC_REQUIRE([AM_PROG_INSTALL_SH])dnl
+# Installed binaries are usually stripped using 'strip' when the user
+# run "make install-strip".  However 'strip' might not be the right
+# tool to use in cross-compilation environments, therefore Automake
+# will honor the 'STRIP' environment variable to overrule this program.
+dnl Don't test for $cross_compiling = yes, because it might be 'maybe'.
+if test "$cross_compiling" != no; then
+  AC_CHECK_TOOL([STRIP], [strip], :)
+fi
+INSTALL_STRIP_PROGRAM="\$(install_sh) -c -s"
+AC_SUBST([INSTALL_STRIP_PROGRAM])])
+
+# Copyright (C) 2006-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_SUBST_NOTMAKE(VARIABLE)
+# ---------------------------
+# Prevent Automake from outputting VARIABLE = @VARIABLE@ in Makefile.in.
+# This macro is traced by Automake.
+AC_DEFUN([_AM_SUBST_NOTMAKE])
+
+# AM_SUBST_NOTMAKE(VARIABLE)
+# --------------------------
+# Public sister of _AM_SUBST_NOTMAKE.
+AC_DEFUN([AM_SUBST_NOTMAKE], [_AM_SUBST_NOTMAKE($@)])
+
+# Check how to create a tarball.                            -*- Autoconf -*-
+
+# Copyright (C) 2004-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_PROG_TAR(FORMAT)
+# --------------------
+# Check how to create a tarball in format FORMAT.
+# FORMAT should be one of 'v7', 'ustar', or 'pax'.
+#
+# Substitute a variable $(am__tar) that is a command
+# writing to stdout a FORMAT-tarball containing the directory
+# $tardir.
+#     tardir=directory && $(am__tar) > result.tar
+#
+# Substitute a variable $(am__untar) that extract such
+# a tarball read from stdin.
+#     $(am__untar) < result.tar
+#
+AC_DEFUN([_AM_PROG_TAR],
+[# Always define AMTAR for backward compatibility.  Yes, it's still used
+# in the wild :-(  We should find a proper way to deprecate it ...
+AC_SUBST([AMTAR], ['$${TAR-tar}'])
+
+# We'll loop over all known methods to create a tar archive until one works.
+_am_tools='gnutar m4_if([$1], [ustar], [plaintar]) pax cpio none'
+
+m4_if([$1], [v7],
+  [am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'],
+
+  [m4_case([$1],
+    [ustar],
+     [# The POSIX 1988 'ustar' format is defined with fixed-size fields.
+      # There is notably a 21 bits limit for the UID and the GID.  In fact,
+      # the 'pax' utility can hang on bigger UID/GID (see automake bug#8343
+      # and bug#13588).
+      am_max_uid=2097151 # 2^21 - 1
+      am_max_gid=$am_max_uid
+      # The $UID and $GID variables are not portable, so we need to resort
+      # to the POSIX-mandated id(1) utility.  Errors in the 'id' calls
+      # below are definitely unexpected, so allow the users to see them
+      # (that is, avoid stderr redirection).
+      am_uid=`id -u || echo unknown`
+      am_gid=`id -g || echo unknown`
+      AC_MSG_CHECKING([whether UID '$am_uid' is supported by ustar format])
+      if test $am_uid -le $am_max_uid; then
+         AC_MSG_RESULT([yes])
+      else
+         AC_MSG_RESULT([no])
+         _am_tools=none
+      fi
+      AC_MSG_CHECKING([whether GID '$am_gid' is supported by ustar format])
+      if test $am_gid -le $am_max_gid; then
+         AC_MSG_RESULT([yes])
+      else
+        AC_MSG_RESULT([no])
+        _am_tools=none
+      fi],
+
+  [pax],
+    [],
+
+  [m4_fatal([Unknown tar format])])
+
+  AC_MSG_CHECKING([how to create a $1 tar archive])
+
+  # Go ahead even if we have the value already cached.  We do so because we
+  # need to set the values for the 'am__tar' and 'am__untar' variables.
+  _am_tools=${am_cv_prog_tar_$1-$_am_tools}
+
+  for _am_tool in $_am_tools; do
+    case $_am_tool in
+    gnutar)
+      for _am_tar in tar gnutar gtar; do
+        AM_RUN_LOG([$_am_tar --version]) && break
+      done
+      am__tar="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$$tardir"'
+      am__tar_="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$tardir"'
+      am__untar="$_am_tar -xf -"
+      ;;
+    plaintar)
+      # Must skip GNU tar: if it does not support --format= it doesn't create
+      # ustar tarball either.
+      (tar --version) >/dev/null 2>&1 && continue
+      am__tar='tar chf - "$$tardir"'
+      am__tar_='tar chf - "$tardir"'
+      am__untar='tar xf -'
+      ;;
+    pax)
+      am__tar='pax -L -x $1 -w "$$tardir"'
+      am__tar_='pax -L -x $1 -w "$tardir"'
+      am__untar='pax -r'
+      ;;
+    cpio)
+      am__tar='find "$$tardir" -print | cpio -o -H $1 -L'
+      am__tar_='find "$tardir" -print | cpio -o -H $1 -L'
+      am__untar='cpio -i -H $1 -d'
+      ;;
+    none)
+      am__tar=false
+      am__tar_=false
+      am__untar=false
+      ;;
+    esac
+
+    # If the value was cached, stop now.  We just wanted to have am__tar
+    # and am__untar set.
+    test -n "${am_cv_prog_tar_$1}" && break
+
+    # tar/untar a dummy directory, and stop if the command works.
+    rm -rf conftest.dir
+    mkdir conftest.dir
+    echo GrepMe > conftest.dir/file
+    AM_RUN_LOG([tardir=conftest.dir && eval $am__tar_ >conftest.tar])
+    rm -rf conftest.dir
+    if test -s conftest.tar; then
+      AM_RUN_LOG([$am__untar <conftest.tar])
+      AM_RUN_LOG([cat conftest.dir/file])
+      grep GrepMe conftest.dir/file >/dev/null 2>&1 && break
+    fi
+  done
+  rm -rf conftest.dir
+
+  AC_CACHE_VAL([am_cv_prog_tar_$1], [am_cv_prog_tar_$1=$_am_tool])
+  AC_MSG_RESULT([$am_cv_prog_tar_$1])])
+
+AC_SUBST([am__tar])
+AC_SUBST([am__untar])
+]) # _AM_PROG_TAR
+
+m4_include([scripts/libtool.m4])
+m4_include([scripts/ltoptions.m4])
+m4_include([scripts/ltsugar.m4])
+m4_include([scripts/ltversion.m4])
+m4_include([scripts/lt~obsolete.m4])
diff --git a/extern/libpng/arm/arm_init.c b/extern/libpng/arm/arm_init.c
new file mode 100644
index 0000000000..a34ecdbef7
--- /dev/null
+++ b/extern/libpng/arm/arm_init.c
@@ -0,0 +1,136 @@
+
+/* arm_init.c - NEON optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2014,2016 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
+ * called.
+ */
+#define _POSIX_SOURCE 1
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_ARM_NEON_OPT > 0
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
+/* WARNING: it is strongly recommended that you do not build libpng with
+ * run-time checks for CPU features if at all possible.  In the case of the ARM
+ * NEON instructions there is no processor-specific way of detecting the
+ * presence of the required support, therefore run-time detection is extremely
+ * OS specific.
+ *
+ * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing
+ * a fragment of C source code which defines the png_have_neon function.  There
+ * are a number of implementations in contrib/arm-neon, but the only one that
+ * has partial support is contrib/arm-neon/linux.c - a generic Linux
+ * implementation which reads /proc/cpufino.
+ */
+#ifndef PNG_ARM_NEON_FILE
+#  ifdef __linux__
+#     define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c"
+#  endif
+#endif
+
+#ifdef PNG_ARM_NEON_FILE
+
+#include <signal.h> /* for sig_atomic_t */
+static int png_have_neon(png_structp png_ptr);
+#include PNG_ARM_NEON_FILE
+
+#else  /* PNG_ARM_NEON_FILE */
+#  error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks"
+#endif /* PNG_ARM_NEON_FILE */
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
+
+#ifndef PNG_ALIGNED_MEMORY_SUPPORTED
+#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#endif
+
+void
+png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
+{
+   /* The switch statement is compiled in for ARM_NEON_API, the call to
+    * png_have_neon is compiled in for ARM_NEON_CHECK.  If both are defined
+    * the check is only performed if the API has not set the NEON option on
+    * or off explicitly.  In this case the check controls what happens.
+    *
+    * If the CHECK is not compiled in and the option is UNSET the behavior prior
+    * to 1.6.7 was to use the NEON code - this was a bug caused by having the
+    * wrong order of the 'ON' and 'default' cases.  UNSET now defaults to OFF,
+    * as documented in png.h
+    */
+   png_debug(1, "in png_init_filter_functions_neon");
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+   switch ((pp->options >> PNG_ARM_NEON) & 3)
+   {
+      case PNG_OPTION_UNSET:
+         /* Allow the run-time check to execute if it has been enabled -
+          * thus both API and CHECK can be turned on.  If it isn't supported
+          * this case will fall through to the 'default' below, which just
+          * returns.
+          */
+#endif /* PNG_ARM_NEON_API_SUPPORTED */
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
+         {
+            static volatile sig_atomic_t no_neon = -1; /* not checked */
+
+            if (no_neon < 0)
+               no_neon = !png_have_neon(pp);
+
+            if (no_neon)
+               return;
+         }
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+         break;
+#endif
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
+
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+      default: /* OFF or INVALID */
+         return;
+
+      case PNG_OPTION_ON:
+         /* Option turned on */
+         break;
+   }
+#endif
+
+   /* IMPORTANT: any new external functions used here must be declared using
+    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
+    * 'prefix' option to configure works:
+    *
+    *    ./configure --with-libpng-prefix=foobar_
+    *
+    * Verify you have got this right by running the above command, doing a build
+    * and examining pngprefix.h; it must contain a #define for every external
+    * function you add.  (Notice that this happens automatically for the
+    * initialization function.)
+    */
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
+
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth3_neon;
+   }
+
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+          png_read_filter_row_paeth4_neon;
+   }
+}
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* READ */
diff --git a/extern/libpng/arm/filter_neon.S b/extern/libpng/arm/filter_neon.S
new file mode 100644
index 0000000000..2308aad13e
--- /dev/null
+++ b/extern/libpng/arm/filter_neon.S
@@ -0,0 +1,253 @@
+
+/* filter_neon.S - NEON optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2014,2017 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* This is required to get the symbol renames, which are #defines, and the
+ * definitions (or not) of PNG_ARM_NEON_OPT and PNG_ARM_NEON_IMPLEMENTATION.
+ */
+#define PNG_VERSION_INFO_ONLY
+#include "../pngpriv.h"
+
+#if (defined(__linux__) || defined(__FreeBSD__)) && defined(__ELF__)
+.section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
+#endif
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Assembler NEON support - only works for 32-bit ARM (i.e. it does not work for
+ * ARM64).  The code in arm/filter_neon_intrinsics.c supports ARM64, however it
+ * only works if -mfpu=neon is specified on the GCC command line.  See pngpriv.h
+ * for the logic which sets PNG_USE_ARM_NEON_ASM:
+ */
+#if PNG_ARM_NEON_IMPLEMENTATION == 2 /* hand-coded assembler */
+
+#if PNG_ARM_NEON_OPT > 0
+
+#ifdef __ELF__
+#   define ELF
+#else
+#   define ELF @
+#endif
+
+        .arch armv7-a
+        .fpu  neon
+
+.macro  func    name, export=0
+    .macro endfunc
+ELF     .size   \name, . - \name
+        .endfunc
+        .purgem endfunc
+    .endm
+        .text
+
+        /* Explicitly specifying alignment here because some versions of
+         * GAS don't align code correctly.  This is harmless in correctly
+         * written versions of GAS.
+         */
+        .align 2
+
+    .if \export
+        .global \name
+    .endif
+ELF     .type   \name, STT_FUNC
+        .func   \name
+\name:
+.endm
+
+func    png_read_filter_row_sub4_neon, export=1
+        ldr             r3,  [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+1:
+        vld4.32         {d4[],d5[],d6[],d7[]},    [r1,:128]
+        vadd.u8         d0,  d3,  d4
+        vadd.u8         d1,  d0,  d5
+        vadd.u8         d2,  d1,  d6
+        vadd.u8         d3,  d2,  d7
+        vst4.32         {d0[0],d1[0],d2[0],d3[0]},[r1,:128]!
+        subs            r3,  r3,  #16
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_sub3_neon, export=1
+        ldr             r3,  [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+        mov             r0,  r1
+        mov             r2,  #3
+        mov             r12, #12
+        vld1.8          {q11},    [r0], r12
+1:
+        vext.8          d5,  d22, d23, #3
+        vadd.u8         d0,  d3,  d22
+        vext.8          d6,  d22, d23, #6
+        vadd.u8         d1,  d0,  d5
+        vext.8          d7,  d23, d23, #1
+        vld1.8          {q11},    [r0], r12
+        vst1.32         {d0[0]},  [r1,:32], r2
+        vadd.u8         d2,  d1,  d6
+        vst1.32         {d1[0]},  [r1], r2
+        vadd.u8         d3,  d2,  d7
+        vst1.32         {d2[0]},  [r1], r2
+        vst1.32         {d3[0]},  [r1], r2
+        subs            r3,  r3,  #12
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_up_neon, export=1
+        ldr             r3,  [r0, #4]           @ rowbytes
+1:
+        vld1.8          {q0}, [r1,:128]
+        vld1.8          {q1}, [r2,:128]!
+        vadd.u8         q0,  q0,  q1
+        vst1.8          {q0}, [r1,:128]!
+        subs            r3,  r3,  #16
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_avg4_neon, export=1
+        ldr             r12, [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+1:
+        vld4.32         {d4[],d5[],d6[],d7[]},    [r1,:128]
+        vld4.32         {d16[],d17[],d18[],d19[]},[r2,:128]!
+        vhadd.u8        d0,  d3,  d16
+        vadd.u8         d0,  d0,  d4
+        vhadd.u8        d1,  d0,  d17
+        vadd.u8         d1,  d1,  d5
+        vhadd.u8        d2,  d1,  d18
+        vadd.u8         d2,  d2,  d6
+        vhadd.u8        d3,  d2,  d19
+        vadd.u8         d3,  d3,  d7
+        vst4.32         {d0[0],d1[0],d2[0],d3[0]},[r1,:128]!
+        subs            r12, r12, #16
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_avg3_neon, export=1
+        push            {r4,lr}
+        ldr             r12, [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+        mov             r0,  r1
+        mov             r4,  #3
+        mov             lr,  #12
+        vld1.8          {q11},    [r0], lr
+1:
+        vld1.8          {q10},    [r2], lr
+        vext.8          d5,  d22, d23, #3
+        vhadd.u8        d0,  d3,  d20
+        vext.8          d17, d20, d21, #3
+        vadd.u8         d0,  d0,  d22
+        vext.8          d6,  d22, d23, #6
+        vhadd.u8        d1,  d0,  d17
+        vext.8          d18, d20, d21, #6
+        vadd.u8         d1,  d1,  d5
+        vext.8          d7,  d23, d23, #1
+        vld1.8          {q11},    [r0], lr
+        vst1.32         {d0[0]},  [r1,:32], r4
+        vhadd.u8        d2,  d1,  d18
+        vst1.32         {d1[0]},  [r1], r4
+        vext.8          d19, d21, d21, #1
+        vadd.u8         d2,  d2,  d6
+        vhadd.u8        d3,  d2,  d19
+        vst1.32         {d2[0]},  [r1], r4
+        vadd.u8         d3,  d3,  d7
+        vst1.32         {d3[0]},  [r1], r4
+        subs            r12, r12, #12
+        bgt             1b
+
+        pop             {r4,pc}
+endfunc
+
+.macro  paeth           rx,  ra,  rb,  rc
+        vaddl.u8        q12, \ra, \rb           @ a + b
+        vaddl.u8        q15, \rc, \rc           @ 2*c
+        vabdl.u8        q13, \rb, \rc           @ pa
+        vabdl.u8        q14, \ra, \rc           @ pb
+        vabd.u16        q15, q12, q15           @ pc
+        vcle.u16        q12, q13, q14           @ pa <= pb
+        vcle.u16        q13, q13, q15           @ pa <= pc
+        vcle.u16        q14, q14, q15           @ pb <= pc
+        vand            q12, q12, q13           @ pa <= pb && pa <= pc
+        vmovn.u16       d28, q14
+        vmovn.u16       \rx, q12
+        vbsl            d28, \rb, \rc
+        vbsl            \rx, \ra, d28
+.endm
+
+func    png_read_filter_row_paeth4_neon, export=1
+        ldr             r12, [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+        vmov.i8         d20, #0
+1:
+        vld4.32         {d4[],d5[],d6[],d7[]},    [r1,:128]
+        vld4.32         {d16[],d17[],d18[],d19[]},[r2,:128]!
+        paeth           d0,  d3,  d16, d20
+        vadd.u8         d0,  d0,  d4
+        paeth           d1,  d0,  d17, d16
+        vadd.u8         d1,  d1,  d5
+        paeth           d2,  d1,  d18, d17
+        vadd.u8         d2,  d2,  d6
+        paeth           d3,  d2,  d19, d18
+        vmov            d20, d19
+        vadd.u8         d3,  d3,  d7
+        vst4.32         {d0[0],d1[0],d2[0],d3[0]},[r1,:128]!
+        subs            r12, r12, #16
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_paeth3_neon, export=1
+        push            {r4,lr}
+        ldr             r12, [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+        vmov.i8         d4,  #0
+        mov             r0,  r1
+        mov             r4,  #3
+        mov             lr,  #12
+        vld1.8          {q11},    [r0], lr
+1:
+        vld1.8          {q10},    [r2], lr
+        paeth           d0,  d3,  d20, d4
+        vext.8          d5,  d22, d23, #3
+        vadd.u8         d0,  d0,  d22
+        vext.8          d17, d20, d21, #3
+        paeth           d1,  d0,  d17, d20
+        vst1.32         {d0[0]},  [r1,:32], r4
+        vext.8          d6,  d22, d23, #6
+        vadd.u8         d1,  d1,  d5
+        vext.8          d18, d20, d21, #6
+        paeth           d2,  d1,  d18, d17
+        vext.8          d7,  d23, d23, #1
+        vld1.8          {q11},    [r0], lr
+        vst1.32         {d1[0]},  [r1], r4
+        vadd.u8         d2,  d2,  d6
+        vext.8          d19, d21, d21, #1
+        paeth           d3,  d2,  d19, d18
+        vst1.32         {d2[0]},  [r1], r4
+        vmov            d4,  d19
+        vadd.u8         d3,  d3,  d7
+        vst1.32         {d3[0]},  [r1], r4
+        subs            r12, r12, #12
+        bgt             1b
+
+        pop             {r4,pc}
+endfunc
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* PNG_ARM_NEON_IMPLEMENTATION == 2 (assembler) */
+#endif /* READ */
diff --git a/extern/libpng/arm/filter_neon_intrinsics.c b/extern/libpng/arm/filter_neon_intrinsics.c
new file mode 100644
index 0000000000..553c0be21c
--- /dev/null
+++ b/extern/libpng/arm/filter_neon_intrinsics.c
@@ -0,0 +1,402 @@
+
+/* filter_neon_intrinsics.c - NEON optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2014,2016 Glenn Randers-Pehrson
+ * Written by James Yu <james.yu at linaro.org>, October 2013.
+ * Based on filter_neon.S, written by Mans Rullgard, 2011.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* This code requires -mfpu=neon on the command line: */
+#if PNG_ARM_NEON_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+#if defined(_MSC_VER) && defined(_M_ARM64)
+#  include <arm64_neon.h>
+#else
+#  include <arm_neon.h>
+#endif
+
+/* libpng row pointers are not necessarily aligned to any particular boundary,
+ * however this code will only work with appropriate alignment.  arm/arm_init.c
+ * checks for this (and will not compile unless it is done). This code uses
+ * variants of png_aligncast to avoid compiler warnings.
+ */
+#define png_ptr(type,pointer) png_aligncast(type *,pointer)
+#define png_ptrc(type,pointer) png_aligncastconst(const type *,pointer)
+
+/* The following relies on a variable 'temp_pointer' being declared with type
+ * 'type'.  This is written this way just to hide the GCC strict aliasing
+ * warning; note that the code is safe because there never is an alias between
+ * the input and output pointers.
+ *
+ * When compiling with MSVC ARM64, the png_ldr macro can't be passed directly
+ * to vst4_lane_u32, because of an internal compiler error inside MSVC.
+ * To avoid this compiler bug, we use a temporary variable (vdest_val) to store
+ * the result of png_ldr.
+ */
+#define png_ldr(type,pointer)\
+   (temp_pointer = png_ptr(type,pointer), *temp_pointer)
+
+#if PNG_ARM_NEON_OPT > 0
+
+void
+png_read_filter_row_up_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+   png_const_bytep pp = prev_row;
+
+   png_debug(1, "in png_read_filter_row_up_neon");
+
+   for (; rp < rp_stop; rp += 16, pp += 16)
+   {
+      uint8x16_t qrp, qpp;
+
+      qrp = vld1q_u8(rp);
+      qpp = vld1q_u8(pp);
+      qrp = vaddq_u8(qrp, qpp);
+      vst1q_u8(rp, qrp);
+   }
+}
+
+void
+png_read_filter_row_sub3_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x16_t vtmp = vld1q_u8(rp);
+   uint8x8x2_t *vrpt = png_ptr(uint8x8x2_t, &vtmp);
+   uint8x8x2_t vrp = *vrpt;
+
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   png_debug(1, "in png_read_filter_row_sub3_neon");
+
+   for (; rp < rp_stop;)
+   {
+      uint8x8_t vtmp1, vtmp2;
+      uint32x2_t *temp_pointer;
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+      vdest.val[0] = vadd_u8(vdest.val[3], vrp.val[0]);
+      vtmp2 = vext_u8(vrp.val[0], vrp.val[1], 6);
+      vdest.val[1] = vadd_u8(vdest.val[0], vtmp1);
+
+      vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+      vdest.val[2] = vadd_u8(vdest.val[1], vtmp2);
+      vdest.val[3] = vadd_u8(vdest.val[2], vtmp1);
+
+      vtmp = vld1q_u8(rp + 12);
+      vrpt = png_ptr(uint8x8x2_t, &vtmp);
+      vrp = *vrpt;
+
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+      rp += 3;
+   }
+
+   PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_sub4_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   png_debug(1, "in png_read_filter_row_sub4_neon");
+
+   for (; rp < rp_stop; rp += 16)
+   {
+      uint32x2x4_t vtmp = vld4_u32(png_ptr(uint32_t,rp));
+      uint8x8x4_t *vrpt = png_ptr(uint8x8x4_t,&vtmp);
+      uint8x8x4_t vrp = *vrpt;
+      uint32x2x4_t *temp_pointer;
+      uint32x2x4_t vdest_val;
+
+      vdest.val[0] = vadd_u8(vdest.val[3], vrp.val[0]);
+      vdest.val[1] = vadd_u8(vdest.val[0], vrp.val[1]);
+      vdest.val[2] = vadd_u8(vdest.val[1], vrp.val[2]);
+      vdest.val[3] = vadd_u8(vdest.val[2], vrp.val[3]);
+
+      vdest_val = png_ldr(uint32x2x4_t, &vdest);
+      vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
+   }
+
+   PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_avg3_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x16_t vtmp;
+   uint8x8x2_t *vrpt;
+   uint8x8x2_t vrp;
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   vtmp = vld1q_u8(rp);
+   vrpt = png_ptr(uint8x8x2_t,&vtmp);
+   vrp = *vrpt;
+
+   png_debug(1, "in png_read_filter_row_avg3_neon");
+
+   for (; rp < rp_stop; pp += 12)
+   {
+      uint8x8_t vtmp1, vtmp2, vtmp3;
+
+      uint8x8x2_t *vppt;
+      uint8x8x2_t vpp;
+
+      uint32x2_t *temp_pointer;
+
+      vtmp = vld1q_u8(pp);
+      vppt = png_ptr(uint8x8x2_t,&vtmp);
+      vpp = *vppt;
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+      vdest.val[0] = vhadd_u8(vdest.val[3], vpp.val[0]);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+
+      vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 3);
+      vtmp3 = vext_u8(vrp.val[0], vrp.val[1], 6);
+      vdest.val[1] = vhadd_u8(vdest.val[0], vtmp2);
+      vdest.val[1] = vadd_u8(vdest.val[1], vtmp1);
+
+      vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 6);
+      vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+
+      vtmp = vld1q_u8(rp + 12);
+      vrpt = png_ptr(uint8x8x2_t,&vtmp);
+      vrp = *vrpt;
+
+      vdest.val[2] = vhadd_u8(vdest.val[1], vtmp2);
+      vdest.val[2] = vadd_u8(vdest.val[2], vtmp3);
+
+      vtmp2 = vext_u8(vpp.val[1], vpp.val[1], 1);
+
+      vdest.val[3] = vhadd_u8(vdest.val[2], vtmp2);
+      vdest.val[3] = vadd_u8(vdest.val[3], vtmp1);
+
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+      rp += 3;
+   }
+}
+
+void
+png_read_filter_row_avg4_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+   png_const_bytep pp = prev_row;
+
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   png_debug(1, "in png_read_filter_row_avg4_neon");
+
+   for (; rp < rp_stop; rp += 16, pp += 16)
+   {
+      uint32x2x4_t vtmp;
+      uint8x8x4_t *vrpt, *vppt;
+      uint8x8x4_t vrp, vpp;
+      uint32x2x4_t *temp_pointer;
+      uint32x2x4_t vdest_val;
+
+      vtmp = vld4_u32(png_ptr(uint32_t,rp));
+      vrpt = png_ptr(uint8x8x4_t,&vtmp);
+      vrp = *vrpt;
+      vtmp = vld4_u32(png_ptrc(uint32_t,pp));
+      vppt = png_ptr(uint8x8x4_t,&vtmp);
+      vpp = *vppt;
+
+      vdest.val[0] = vhadd_u8(vdest.val[3], vpp.val[0]);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+      vdest.val[1] = vhadd_u8(vdest.val[0], vpp.val[1]);
+      vdest.val[1] = vadd_u8(vdest.val[1], vrp.val[1]);
+      vdest.val[2] = vhadd_u8(vdest.val[1], vpp.val[2]);
+      vdest.val[2] = vadd_u8(vdest.val[2], vrp.val[2]);
+      vdest.val[3] = vhadd_u8(vdest.val[2], vpp.val[3]);
+      vdest.val[3] = vadd_u8(vdest.val[3], vrp.val[3]);
+
+      vdest_val = png_ldr(uint32x2x4_t, &vdest);
+      vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
+   }
+}
+
+static uint8x8_t
+paeth(uint8x8_t a, uint8x8_t b, uint8x8_t c)
+{
+   uint8x8_t d, e;
+   uint16x8_t p1, pa, pb, pc;
+
+   p1 = vaddl_u8(a, b); /* a + b */
+   pc = vaddl_u8(c, c); /* c * 2 */
+   pa = vabdl_u8(b, c); /* pa */
+   pb = vabdl_u8(a, c); /* pb */
+   pc = vabdq_u16(p1, pc); /* pc */
+
+   p1 = vcleq_u16(pa, pb); /* pa <= pb */
+   pa = vcleq_u16(pa, pc); /* pa <= pc */
+   pb = vcleq_u16(pb, pc); /* pb <= pc */
+
+   p1 = vandq_u16(p1, pa); /* pa <= pb && pa <= pc */
+
+   d = vmovn_u16(pb);
+   e = vmovn_u16(p1);
+
+   d = vbsl_u8(d, b, c);
+   e = vbsl_u8(e, a, d);
+
+   return e;
+}
+
+void
+png_read_filter_row_paeth3_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x16_t vtmp;
+   uint8x8x2_t *vrpt;
+   uint8x8x2_t vrp;
+   uint8x8_t vlast = vdup_n_u8(0);
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   vtmp = vld1q_u8(rp);
+   vrpt = png_ptr(uint8x8x2_t,&vtmp);
+   vrp = *vrpt;
+
+   png_debug(1, "in png_read_filter_row_paeth3_neon");
+
+   for (; rp < rp_stop; pp += 12)
+   {
+      uint8x8x2_t *vppt;
+      uint8x8x2_t vpp;
+      uint8x8_t vtmp1, vtmp2, vtmp3;
+      uint32x2_t *temp_pointer;
+
+      vtmp = vld1q_u8(pp);
+      vppt = png_ptr(uint8x8x2_t,&vtmp);
+      vpp = *vppt;
+
+      vdest.val[0] = paeth(vdest.val[3], vpp.val[0], vlast);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+      vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 3);
+      vdest.val[1] = paeth(vdest.val[0], vtmp2, vpp.val[0]);
+      vdest.val[1] = vadd_u8(vdest.val[1], vtmp1);
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 6);
+      vtmp3 = vext_u8(vpp.val[0], vpp.val[1], 6);
+      vdest.val[2] = paeth(vdest.val[1], vtmp3, vtmp2);
+      vdest.val[2] = vadd_u8(vdest.val[2], vtmp1);
+
+      vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+      vtmp2 = vext_u8(vpp.val[1], vpp.val[1], 1);
+
+      vtmp = vld1q_u8(rp + 12);
+      vrpt = png_ptr(uint8x8x2_t,&vtmp);
+      vrp = *vrpt;
+
+      vdest.val[3] = paeth(vdest.val[2], vtmp2, vtmp3);
+      vdest.val[3] = vadd_u8(vdest.val[3], vtmp1);
+
+      vlast = vtmp2;
+
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+      rp += 3;
+   }
+}
+
+void
+png_read_filter_row_paeth4_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+   png_const_bytep pp = prev_row;
+
+   uint8x8_t vlast = vdup_n_u8(0);
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   png_debug(1, "in png_read_filter_row_paeth4_neon");
+
+   for (; rp < rp_stop; rp += 16, pp += 16)
+   {
+      uint32x2x4_t vtmp;
+      uint8x8x4_t *vrpt, *vppt;
+      uint8x8x4_t vrp, vpp;
+      uint32x2x4_t *temp_pointer;
+      uint32x2x4_t vdest_val;
+
+      vtmp = vld4_u32(png_ptr(uint32_t,rp));
+      vrpt = png_ptr(uint8x8x4_t,&vtmp);
+      vrp = *vrpt;
+      vtmp = vld4_u32(png_ptrc(uint32_t,pp));
+      vppt = png_ptr(uint8x8x4_t,&vtmp);
+      vpp = *vppt;
+
+      vdest.val[0] = paeth(vdest.val[3], vpp.val[0], vlast);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+      vdest.val[1] = paeth(vdest.val[0], vpp.val[1], vpp.val[0]);
+      vdest.val[1] = vadd_u8(vdest.val[1], vrp.val[1]);
+      vdest.val[2] = paeth(vdest.val[1], vpp.val[2], vpp.val[1]);
+      vdest.val[2] = vadd_u8(vdest.val[2], vrp.val[2]);
+      vdest.val[3] = paeth(vdest.val[2], vpp.val[3], vpp.val[2]);
+      vdest.val[3] = vadd_u8(vdest.val[3], vrp.val[3]);
+
+      vlast = vpp.val[3];
+
+      vdest_val = png_ldr(uint32x2x4_t, &vdest);
+      vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
+   }
+}
+
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* PNG_ARM_NEON_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */
diff --git a/extern/libpng/arm/palette_neon_intrinsics.c b/extern/libpng/arm/palette_neon_intrinsics.c
new file mode 100644
index 0000000000..b4d1fd2abf
--- /dev/null
+++ b/extern/libpng/arm/palette_neon_intrinsics.c
@@ -0,0 +1,149 @@
+
+/* palette_neon_intrinsics.c - NEON optimised palette expansion functions
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 2017-2018 Arm Holdings. All rights reserved.
+ * Written by Richard Townsend <Richard.Townsend@arm.com>, February 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "../pngpriv.h"
+
+#if PNG_ARM_NEON_IMPLEMENTATION == 1
+
+#if defined(_MSC_VER) && defined(_M_ARM64)
+#  include <arm64_neon.h>
+#else
+#  include <arm_neon.h>
+#endif
+
+/* Build an RGBA8 palette from the separate RGB and alpha palettes. */
+void
+png_riffle_palette_neon(png_structrp png_ptr)
+{
+   png_const_colorp palette = png_ptr->palette;
+   png_bytep riffled_palette = png_ptr->riffled_palette;
+   png_const_bytep trans_alpha = png_ptr->trans_alpha;
+   int num_trans = png_ptr->num_trans;
+   int i;
+
+   png_debug(1, "in png_riffle_palette_neon");
+
+   /* Initially black, opaque. */
+   uint8x16x4_t w = {{
+      vdupq_n_u8(0x00),
+      vdupq_n_u8(0x00),
+      vdupq_n_u8(0x00),
+      vdupq_n_u8(0xff),
+   }};
+
+   /* First, riffle the RGB colours into an RGBA8 palette.
+    * The alpha component is set to opaque for now.
+    */
+   for (i = 0; i < 256; i += 16)
+   {
+      uint8x16x3_t v = vld3q_u8((png_const_bytep)(palette + i));
+      w.val[0] = v.val[0];
+      w.val[1] = v.val[1];
+      w.val[2] = v.val[2];
+      vst4q_u8(riffled_palette + (i << 2), w);
+   }
+
+   /* Fix up the missing transparency values. */
+   for (i = 0; i < num_trans; i++)
+      riffled_palette[(i << 2) + 3] = trans_alpha[i];
+}
+
+/* Expands a palettized row into RGBA8. */
+int
+png_do_expand_palette_rgba8_neon(png_structrp png_ptr, png_row_infop row_info,
+    png_const_bytep row, png_bytepp ssp, png_bytepp ddp)
+{
+   png_uint_32 row_width = row_info->width;
+   const png_uint_32 *riffled_palette =
+      (const png_uint_32 *)png_ptr->riffled_palette;
+   const png_int_32 pixels_per_chunk = 4;
+   int i;
+
+   png_debug(1, "in png_do_expand_palette_rgba8_neon");
+
+   if (row_width < pixels_per_chunk)
+      return 0;
+
+   /* This function originally gets the last byte of the output row.
+    * The NEON part writes forward from a given position, so we have
+    * to seek this back by 4 pixels x 4 bytes.
+    */
+   *ddp = *ddp - ((pixels_per_chunk * sizeof(png_uint_32)) - 1);
+
+   for (i = 0; i < row_width; i += pixels_per_chunk)
+   {
+      uint32x4_t cur;
+      png_bytep sp = *ssp - i, dp = *ddp - (i << 2);
+      cur = vld1q_dup_u32 (riffled_palette + *(sp - 3));
+      cur = vld1q_lane_u32(riffled_palette + *(sp - 2), cur, 1);
+      cur = vld1q_lane_u32(riffled_palette + *(sp - 1), cur, 2);
+      cur = vld1q_lane_u32(riffled_palette + *(sp - 0), cur, 3);
+      vst1q_u32((void *)dp, cur);
+   }
+   if (i != row_width)
+   {
+      /* Remove the amount that wasn't processed. */
+      i -= pixels_per_chunk;
+   }
+
+   /* Decrement output pointers. */
+   *ssp = *ssp - i;
+   *ddp = *ddp - (i << 2);
+   return i;
+}
+
+/* Expands a palettized row into RGB8. */
+int
+png_do_expand_palette_rgb8_neon(png_structrp png_ptr, png_row_infop row_info,
+    png_const_bytep row, png_bytepp ssp, png_bytepp ddp)
+{
+   png_uint_32 row_width = row_info->width;
+   png_const_bytep palette = (png_const_bytep)png_ptr->palette;
+   const png_uint_32 pixels_per_chunk = 8;
+   int i;
+
+   png_debug(1, "in png_do_expand_palette_rgb8_neon");
+
+   if (row_width <= pixels_per_chunk)
+      return 0;
+
+   /* Seeking this back by 8 pixels x 3 bytes. */
+   *ddp = *ddp - ((pixels_per_chunk * sizeof(png_color)) - 1);
+
+   for (i = 0; i < row_width; i += pixels_per_chunk)
+   {
+      uint8x8x3_t cur;
+      png_bytep sp = *ssp - i, dp = *ddp - ((i << 1) + i);
+      cur = vld3_dup_u8(palette + sizeof(png_color) * (*(sp - 7)));
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 6)), cur, 1);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 5)), cur, 2);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 4)), cur, 3);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 3)), cur, 4);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 2)), cur, 5);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 1)), cur, 6);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 0)), cur, 7);
+      vst3_u8((void *)dp, cur);
+   }
+
+   if (i != row_width)
+   {
+      /* Remove the amount that wasn't processed. */
+      i -= pixels_per_chunk;
+   }
+
+   /* Decrement output pointers. */
+   *ssp = *ssp - i;
+   *ddp = *ddp - ((i << 1) + i);
+   return i;
+}
+
+#endif /* PNG_ARM_NEON_IMPLEMENTATION */
diff --git a/extern/libpng/autogen.sh b/extern/libpng/autogen.sh
new file mode 100755
index 0000000000..a46daf65a8
--- /dev/null
+++ b/extern/libpng/autogen.sh
@@ -0,0 +1,225 @@
+#! /bin/sh
+#
+# Run 'autoreconf' to build 'configure', 'Makefile.in' and other configure
+# control files.
+#
+# The first time this is run on a GIT checkout the only files that exist are
+# configure.ac and Makefile.am; all of the autotools support scripts are
+# missing.  They are instantiated with autoreconf --force --install.
+#
+# For regular ("tarball") distributions all the files should exist.  We do not
+# want them to be updated *under any circumstances*.  It should never be
+# necessary to run autogen.sh because ./configure --enable-maintainer-mode says
+# what to do if Makefile.am or configure.ac are changed.
+#
+# It is *probably* OK to update the files on a GIT checkout, because they have
+# come from the local tools, but leave that to the user who is assumed to know
+# whether it is ok or required.
+#
+# This script is intended to work without arguments, there are, however, hidden
+# arguments (a) for use while testing the script and (b) to fix up systems that
+# have been broken.  If (b) is required the script prompts for the correct
+# options.  For this reason the options are *NOT* documented in the help; this
+# is deliberate; UTSL.
+#
+clean=
+maintainer=
+while test $# -gt 0
+do
+   case "$1" in
+      --maintainer)
+         maintainer=1;;
+
+      --clean)
+         clean=1;;
+
+      *)
+         exec >&2
+         echo "$0: usage: ./autogen.sh"
+         if test -d .git
+         then
+            echo "  ./autogen.sh generates the configure script and"
+            echo "  Makefile.in, or refreshes them after changes to Makefile.am"
+            echo "  or configure.ac.  You may prefer to just run autoreconf."
+         elif test -z "$maintainer"
+         then
+            echo "  DO NOT RUN THIS SCRIPT."
+            echo "  If you need to change Makefile.am or configure.ac then you"
+            echo "  also need to run ./configure --enable-maintainer-mode and"
+            echo "  use the appropriate autotools, *NOT* this script, to update"
+            echo "  everything, please check the documentation of autoreconf."
+            echo "  WARNING: libpng is intentionally generated with a known,"
+            echo "  fixed, set of autotools.  It is known *NOT* to work with"
+            echo "  the collection of autotools distributed on highly reputable"
+            echo "  operating systems."
+            echo "  Remember: autotools is GNU software, you are expected to"
+            echo "  pay for support."
+         else
+            echo "  You have run autogen.sh with --maintainer enabled and you"
+            echo "  are not using a GIT distribution, then you have given an"
+            echo "  unrecognized argument.  This is not good. --maintainer"
+            echo "  switches off any assumptions that you might not know what"
+            echo "  you are doing."
+         fi
+         exit 1;;
+   esac
+
+   shift
+done
+#
+# First check for a set of the autotools files; if absent then this is assumed
+# to be a GIT version and the local autotools must be used.  If present this
+# is a tarball distribution and the script should not be used.  If partially
+# present bad things are happening.
+#
+# The autotools generated files:
+libpng_autotools_files="Makefile.in aclocal.m4 config.guess config.h.in
+   config.sub configure depcomp install-sh ltmain.sh missing\
+   test-driver"
+#
+# Files generated by versions of configue >2.68 or automake >1.13 (i.e. later
+# versions than those required by configure.ac):
+libpng_autotools_extra="compile config.h.in~"
+#
+# These are separate because 'maintainer-clean' does not remove them.
+libpng_libtool_files="scripts/libtool.m4 scripts/ltoptions.m4\
+   scripts/ltsugar.m4 scripts/ltversion.m4 scripts/lt~obsolete.m4"
+
+libpng_autotools_dirs="autom4te.cache" # not required
+#
+# The configure generated files:
+libpng_configure_files="Makefile config.h config.log config.status\
+   libpng-config libpng.pc libtool stamp-h1"
+
+libpng_configure_dirs=".deps"
+#
+# We must remove the configure generated files as well as the autotools
+# generated files if autotools are regenerated because otherwise if configure
+# has been run without "--enable-maintainer-mode" make can do a partial update
+# of Makefile.  These functions do the two bits of cleaning.
+clean_autotools(){
+   rm -rf $libpng_autotools_files $libpng_libtool_files $libpng_autotools_dirs
+   rm -rf $libpng_autotools_extra
+}
+
+clean_configure(){
+   rm -rf $libpng_configure_files $libpng_configure_dirs
+}
+#
+# Clean: remove everything (this is to help with testing)
+if test -n "$clean"
+then
+   clean_configure
+   if test -n "$maintainer"
+   then
+      clean_autotools
+   fi
+
+   exit 0
+fi
+#
+# Validate the distribution.
+libpng_autotools_file_found=
+libpng_autotools_file_missing=
+for file in $libpng_autotools_files
+do
+   if test -f  "$file"
+   then
+      libpng_autotools_file_found=1
+   else
+      libpng_autotools_file_missing=1
+   fi
+done
+#
+# Presence of one of these does not *invalidate* missing, but absence
+# invalidates found.
+for file in $libpng_libtool_files
+do
+   if test ! -f "$file"
+   then
+      libpng_autotools_file_missing=1
+   fi
+done
+#
+# The cache directory doesn't matter - it will be regenerated and does not exist
+# anyway in a tarball.
+#
+# Either everything is missing or everything is there, the --maintainer option
+# just changes this so that the mode is set to generate all the files.
+mode=
+if test -z "$libpng_autotools_file_found" -o -n "$maintainer"
+then
+   mode="autoreconf"
+else
+   if test -n "$libpng_autotools_file_missing"
+   then
+      mode="broken"
+   else
+      mode="configure"
+   fi
+fi
+#
+# So:
+case "$mode" in
+   autoreconf)
+      # Clean in case configure files exist
+      clean_configure
+      clean_autotools
+      # Everything must be initialized, so use --force
+      if autoreconf --warnings=all --force --install
+      then
+         missing=
+         for file in $libpng_autotools_files
+         do
+            test -f "$file" || missing=1
+         done
+         # ignore the cache directory
+         test -z "$missing" || {
+            exec >&2
+            echo "autoreconf was run, but did not produce all the expected"
+            echo "files.  It is likely that your autotools installation is"
+            echo "not compatible with that expected by libpng."
+            exit 1
+         }
+      else
+         exec >&2
+         echo "autoreconf failed: your version of autotools is incompatible"
+         echo "with this libpng version.  Please use a distributed archive"
+         echo "(which includes the autotools generated files) and run configure"
+         echo "instead."
+         exit 1
+      fi;;
+
+   configure)
+      if test -d .git
+      then
+         exec >&2
+         echo "ERROR: running autoreconf on an initialized system"
+         echo "  This is not necessary; it is only necessary to remake the"
+         echo "  autotools generated files if Makefile.am or configure.ac"
+         echo "  change and make does the right thing with:"
+         echo
+         echo "     ./configure --enable-maintainer-mode."
+         echo
+         echo "  You can run autoreconf yourself if you don't like maintainer"
+         echo "  mode and you can also just run autoreconf -f -i to initialize"
+         echo "  everything in the first place; this script is only for"
+         echo "  compatibility with prior releases."
+         exit 1
+      else
+         exec >&2
+         echo "autogen.sh is intended only to generate 'configure' on systems"
+         echo "that do not have it.  You have a complete 'configure', if you"
+         echo "need to change Makefile.am or configure.ac you also need to"
+         echo "run configure with the --enable-maintainer-mode option."
+         exit 1
+      fi;;
+
+   broken)
+      exec >&2
+      echo "Your system has a partial set of autotools generated files."
+      echo "autogen.sh is unable to proceed.  The full set of files is"
+      echo "contained in the libpng 'tar' distribution archive and you do"
+      echo "not need to run autogen.sh if you use it."
+      exit 1;;
+esac
diff --git a/extern/libpng/compile b/extern/libpng/compile
new file mode 100755
index 0000000000..99e50524b3
--- /dev/null
+++ b/extern/libpng/compile
@@ -0,0 +1,348 @@
+#! /bin/sh
+# Wrapper for compilers which do not understand '-c -o'.
+
+scriptversion=2018-03-07.03; # UTC
+
+# Copyright (C) 1999-2018 Free Software Foundation, Inc.
+# Written by Tom Tromey <tromey@cygnus.com>.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# This file is maintained in Automake, please report
+# bugs to <bug-automake@gnu.org> or send patches to
+# <automake-patches@gnu.org>.
+
+nl='
+'
+
+# We need space, tab and new line, in precisely that order.  Quoting is
+# there to prevent tools from complaining about whitespace usage.
+IFS=" ""	$nl"
+
+file_conv=
+
+# func_file_conv build_file lazy
+# Convert a $build file to $host form and store it in $file
+# Currently only supports Windows hosts. If the determined conversion
+# type is listed in (the comma separated) LAZY, no conversion will
+# take place.
+func_file_conv ()
+{
+  file=$1
+  case $file in
+    / | /[!/]*) # absolute file, and not a UNC file
+      if test -z "$file_conv"; then
+	# lazily determine how to convert abs files
+	case `uname -s` in
+	  MINGW*)
+	    file_conv=mingw
+	    ;;
+	  CYGWIN*)
+	    file_conv=cygwin
+	    ;;
+	  *)
+	    file_conv=wine
+	    ;;
+	esac
+      fi
+      case $file_conv/,$2, in
+	*,$file_conv,*)
+	  ;;
+	mingw/*)
+	  file=`cmd //C echo "$file " | sed -e 's/"\(.*\) " *$/\1/'`
+	  ;;
+	cygwin/*)
+	  file=`cygpath -m "$file" || echo "$file"`
+	  ;;
+	wine/*)
+	  file=`winepath -w "$file" || echo "$file"`
+	  ;;
+      esac
+      ;;
+  esac
+}
+
+# func_cl_dashL linkdir
+# Make cl look for libraries in LINKDIR
+func_cl_dashL ()
+{
+  func_file_conv "$1"
+  if test -z "$lib_path"; then
+    lib_path=$file
+  else
+    lib_path="$lib_path;$file"
+  fi
+  linker_opts="$linker_opts -LIBPATH:$file"
+}
+
+# func_cl_dashl library
+# Do a library search-path lookup for cl
+func_cl_dashl ()
+{
+  lib=$1
+  found=no
+  save_IFS=$IFS
+  IFS=';'
+  for dir in $lib_path $LIB
+  do
+    IFS=$save_IFS
+    if $shared && test -f "$dir/$lib.dll.lib"; then
+      found=yes
+      lib=$dir/$lib.dll.lib
+      break
+    fi
+    if test -f "$dir/$lib.lib"; then
+      found=yes
+      lib=$dir/$lib.lib
+      break
+    fi
+    if test -f "$dir/lib$lib.a"; then
+      found=yes
+      lib=$dir/lib$lib.a
+      break
+    fi
+  done
+  IFS=$save_IFS
+
+  if test "$found" != yes; then
+    lib=$lib.lib
+  fi
+}
+
+# func_cl_wrapper cl arg...
+# Adjust compile command to suit cl
+func_cl_wrapper ()
+{
+  # Assume a capable shell
+  lib_path=
+  shared=:
+  linker_opts=
+  for arg
+  do
+    if test -n "$eat"; then
+      eat=
+    else
+      case $1 in
+	-o)
+	  # configure might choose to run compile as 'compile cc -o foo foo.c'.
+	  eat=1
+	  case $2 in
+	    *.o | *.[oO][bB][jJ])
+	      func_file_conv "$2"
+	      set x "$@" -Fo"$file"
+	      shift
+	      ;;
+	    *)
+	      func_file_conv "$2"
+	      set x "$@" -Fe"$file"
+	      shift
+	      ;;
+	  esac
+	  ;;
+	-I)
+	  eat=1
+	  func_file_conv "$2" mingw
+	  set x "$@" -I"$file"
+	  shift
+	  ;;
+	-I*)
+	  func_file_conv "${1#-I}" mingw
+	  set x "$@" -I"$file"
+	  shift
+	  ;;
+	-l)
+	  eat=1
+	  func_cl_dashl "$2"
+	  set x "$@" "$lib"
+	  shift
+	  ;;
+	-l*)
+	  func_cl_dashl "${1#-l}"
+	  set x "$@" "$lib"
+	  shift
+	  ;;
+	-L)
+	  eat=1
+	  func_cl_dashL "$2"
+	  ;;
+	-L*)
+	  func_cl_dashL "${1#-L}"
+	  ;;
+	-static)
+	  shared=false
+	  ;;
+	-Wl,*)
+	  arg=${1#-Wl,}
+	  save_ifs="$IFS"; IFS=','
+	  for flag in $arg; do
+	    IFS="$save_ifs"
+	    linker_opts="$linker_opts $flag"
+	  done
+	  IFS="$save_ifs"
+	  ;;
+	-Xlinker)
+	  eat=1
+	  linker_opts="$linker_opts $2"
+	  ;;
+	-*)
+	  set x "$@" "$1"
+	  shift
+	  ;;
+	*.cc | *.CC | *.cxx | *.CXX | *.[cC]++)
+	  func_file_conv "$1"
+	  set x "$@" -Tp"$file"
+	  shift
+	  ;;
+	*.c | *.cpp | *.CPP | *.lib | *.LIB | *.Lib | *.OBJ | *.obj | *.[oO])
+	  func_file_conv "$1" mingw
+	  set x "$@" "$file"
+	  shift
+	  ;;
+	*)
+	  set x "$@" "$1"
+	  shift
+	  ;;
+      esac
+    fi
+    shift
+  done
+  if test -n "$linker_opts"; then
+    linker_opts="-link$linker_opts"
+  fi
+  exec "$@" $linker_opts
+  exit 1
+}
+
+eat=
+
+case $1 in
+  '')
+     echo "$0: No command.  Try '$0 --help' for more information." 1>&2
+     exit 1;
+     ;;
+  -h | --h*)
+    cat <<\EOF
+Usage: compile [--help] [--version] PROGRAM [ARGS]
+
+Wrapper for compilers which do not understand '-c -o'.
+Remove '-o dest.o' from ARGS, run PROGRAM with the remaining
+arguments, and rename the output as expected.
+
+If you are trying to build a whole package this is not the
+right script to run: please start by reading the file 'INSTALL'.
+
+Report bugs to <bug-automake@gnu.org>.
+EOF
+    exit $?
+    ;;
+  -v | --v*)
+    echo "compile $scriptversion"
+    exit $?
+    ;;
+  cl | *[/\\]cl | cl.exe | *[/\\]cl.exe | \
+  icl | *[/\\]icl | icl.exe | *[/\\]icl.exe )
+    func_cl_wrapper "$@"      # Doesn't return...
+    ;;
+esac
+
+ofile=
+cfile=
+
+for arg
+do
+  if test -n "$eat"; then
+    eat=
+  else
+    case $1 in
+      -o)
+	# configure might choose to run compile as 'compile cc -o foo foo.c'.
+	# So we strip '-o arg' only if arg is an object.
+	eat=1
+	case $2 in
+	  *.o | *.obj)
+	    ofile=$2
+	    ;;
+	  *)
+	    set x "$@" -o "$2"
+	    shift
+	    ;;
+	esac
+	;;
+      *.c)
+	cfile=$1
+	set x "$@" "$1"
+	shift
+	;;
+      *)
+	set x "$@" "$1"
+	shift
+	;;
+    esac
+  fi
+  shift
+done
+
+if test -z "$ofile" || test -z "$cfile"; then
+  # If no '-o' option was seen then we might have been invoked from a
+  # pattern rule where we don't need one.  That is ok -- this is a
+  # normal compilation that the losing compiler can handle.  If no
+  # '.c' file was seen then we are probably linking.  That is also
+  # ok.
+  exec "$@"
+fi
+
+# Name of file we expect compiler to create.
+cofile=`echo "$cfile" | sed 's|^.*[\\/]||; s|^[a-zA-Z]:||; s/\.c$/.o/'`
+
+# Create the lock directory.
+# Note: use '[/\\:.-]' here to ensure that we don't use the same name
+# that we are using for the .o file.  Also, base the name on the expected
+# object file name, since that is what matters with a parallel build.
+lockdir=`echo "$cofile" | sed -e 's|[/\\:.-]|_|g'`.d
+while true; do
+  if mkdir "$lockdir" >/dev/null 2>&1; then
+    break
+  fi
+  sleep 1
+done
+# FIXME: race condition here if user kills between mkdir and trap.
+trap "rmdir '$lockdir'; exit 1" 1 2 15
+
+# Run the compile.
+"$@"
+ret=$?
+
+if test -f "$cofile"; then
+  test "$cofile" = "$ofile" || mv "$cofile" "$ofile"
+elif test -f "${cofile}bj"; then
+  test "${cofile}bj" = "$ofile" || mv "${cofile}bj" "$ofile"
+fi
+
+rmdir "$lockdir"
+exit $ret
+
+# Local Variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
diff --git a/extern/libpng/config.guess b/extern/libpng/config.guess
new file mode 100755
index 0000000000..256083a70d
--- /dev/null
+++ b/extern/libpng/config.guess
@@ -0,0 +1,1476 @@
+#! /bin/sh
+# Attempt to guess a canonical system name.
+#   Copyright 1992-2018 Free Software Foundation, Inc.
+
+timestamp='2018-03-08'
+
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, see <https://www.gnu.org/licenses/>.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that
+# program.  This Exception is an additional permission under section 7
+# of the GNU General Public License, version 3 ("GPLv3").
+#
+# Originally written by Per Bothner; maintained since 2000 by Ben Elliston.
+#
+# You can get the latest version of this script from:
+# https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
+#
+# Please send patches to <config-patches@gnu.org>.
+
+
+me=`echo "$0" | sed -e 's,.*/,,'`
+
+usage="\
+Usage: $0 [OPTION]
+
+Output the configuration name of the system \`$me' is run on.
+
+Options:
+  -h, --help         print this help, then exit
+  -t, --time-stamp   print date of last modification, then exit
+  -v, --version      print version number, then exit
+
+Report bugs and patches to <config-patches@gnu.org>."
+
+version="\
+GNU config.guess ($timestamp)
+
+Originally written by Per Bothner.
+Copyright 1992-2018 Free Software Foundation, Inc.
+
+This is free software; see the source for copying conditions.  There is NO
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
+
+help="
+Try \`$me --help' for more information."
+
+# Parse command line
+while test $# -gt 0 ; do
+  case $1 in
+    --time-stamp | --time* | -t )
+       echo "$timestamp" ; exit ;;
+    --version | -v )
+       echo "$version" ; exit ;;
+    --help | --h* | -h )
+       echo "$usage"; exit ;;
+    -- )     # Stop option processing
+       shift; break ;;
+    - )	# Use stdin as input.
+       break ;;
+    -* )
+       echo "$me: invalid option $1$help" >&2
+       exit 1 ;;
+    * )
+       break ;;
+  esac
+done
+
+if test $# != 0; then
+  echo "$me: too many arguments$help" >&2
+  exit 1
+fi
+
+trap 'exit 1' 1 2 15
+
+# CC_FOR_BUILD -- compiler used by this script. Note that the use of a
+# compiler to aid in system detection is discouraged as it requires
+# temporary files to be created and, as you can see below, it is a
+# headache to deal with in a portable fashion.
+
+# Historically, `CC_FOR_BUILD' used to be named `HOST_CC'. We still
+# use `HOST_CC' if defined, but it is deprecated.
+
+# Portable tmp directory creation inspired by the Autoconf team.
+
+set_cc_for_build='
+trap "exitcode=\$?; (rm -f \$tmpfiles 2>/dev/null; rmdir \$tmp 2>/dev/null) && exit \$exitcode" 0 ;
+trap "rm -f \$tmpfiles 2>/dev/null; rmdir \$tmp 2>/dev/null; exit 1" 1 2 13 15 ;
+: ${TMPDIR=/tmp} ;
+ { tmp=`(umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null` && test -n "$tmp" && test -d "$tmp" ; } ||
+ { test -n "$RANDOM" && tmp=$TMPDIR/cg$$-$RANDOM && (umask 077 && mkdir $tmp) ; } ||
+ { tmp=$TMPDIR/cg-$$ && (umask 077 && mkdir $tmp) && echo "Warning: creating insecure temp directory" >&2 ; } ||
+ { echo "$me: cannot create a temporary directory in $TMPDIR" >&2 ; exit 1 ; } ;
+dummy=$tmp/dummy ;
+tmpfiles="$dummy.c $dummy.o $dummy.rel $dummy" ;
+case $CC_FOR_BUILD,$HOST_CC,$CC in
+ ,,)    echo "int x;" > "$dummy.c" ;
+	for c in cc gcc c89 c99 ; do
+	  if ($c -c -o "$dummy.o" "$dummy.c") >/dev/null 2>&1 ; then
+	     CC_FOR_BUILD="$c"; break ;
+	  fi ;
+	done ;
+	if test x"$CC_FOR_BUILD" = x ; then
+	  CC_FOR_BUILD=no_compiler_found ;
+	fi
+	;;
+ ,,*)   CC_FOR_BUILD=$CC ;;
+ ,*,*)  CC_FOR_BUILD=$HOST_CC ;;
+esac ; set_cc_for_build= ;'
+
+# This is needed to find uname on a Pyramid OSx when run in the BSD universe.
+# (ghazi@noc.rutgers.edu 1994-08-24)
+if (test -f /.attbin/uname) >/dev/null 2>&1 ; then
+	PATH=$PATH:/.attbin ; export PATH
+fi
+
+UNAME_MACHINE=`(uname -m) 2>/dev/null` || UNAME_MACHINE=unknown
+UNAME_RELEASE=`(uname -r) 2>/dev/null` || UNAME_RELEASE=unknown
+UNAME_SYSTEM=`(uname -s) 2>/dev/null`  || UNAME_SYSTEM=unknown
+UNAME_VERSION=`(uname -v) 2>/dev/null` || UNAME_VERSION=unknown
+
+case "$UNAME_SYSTEM" in
+Linux|GNU|GNU/*)
+	# If the system lacks a compiler, then just pick glibc.
+	# We could probably try harder.
+	LIBC=gnu
+
+	eval "$set_cc_for_build"
+	cat <<-EOF > "$dummy.c"
+	#include <features.h>
+	#if defined(__UCLIBC__)
+	LIBC=uclibc
+	#elif defined(__dietlibc__)
+	LIBC=dietlibc
+	#else
+	LIBC=gnu
+	#endif
+	EOF
+	eval "`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^LIBC' | sed 's, ,,g'`"
+
+	# If ldd exists, use it to detect musl libc.
+	if command -v ldd >/dev/null && \
+		ldd --version 2>&1 | grep -q ^musl
+	then
+	    LIBC=musl
+	fi
+	;;
+esac
+
+# Note: order is significant - the case branches are not exclusive.
+
+case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
+    *:NetBSD:*:*)
+	# NetBSD (nbsd) targets should (where applicable) match one or
+	# more of the tuples: *-*-netbsdelf*, *-*-netbsdaout*,
+	# *-*-netbsdecoff* and *-*-netbsd*.  For targets that recently
+	# switched to ELF, *-*-netbsd* would select the old
+	# object file format.  This provides both forward
+	# compatibility and a consistent mechanism for selecting the
+	# object file format.
+	#
+	# Note: NetBSD doesn't particularly care about the vendor
+	# portion of the name.  We always set it to "unknown".
+	sysctl="sysctl -n hw.machine_arch"
+	UNAME_MACHINE_ARCH=`(uname -p 2>/dev/null || \
+	    "/sbin/$sysctl" 2>/dev/null || \
+	    "/usr/sbin/$sysctl" 2>/dev/null || \
+	    echo unknown)`
+	case "$UNAME_MACHINE_ARCH" in
+	    armeb) machine=armeb-unknown ;;
+	    arm*) machine=arm-unknown ;;
+	    sh3el) machine=shl-unknown ;;
+	    sh3eb) machine=sh-unknown ;;
+	    sh5el) machine=sh5le-unknown ;;
+	    earmv*)
+		arch=`echo "$UNAME_MACHINE_ARCH" | sed -e 's,^e\(armv[0-9]\).*$,\1,'`
+		endian=`echo "$UNAME_MACHINE_ARCH" | sed -ne 's,^.*\(eb\)$,\1,p'`
+		machine="${arch}${endian}"-unknown
+		;;
+	    *) machine="$UNAME_MACHINE_ARCH"-unknown ;;
+	esac
+	# The Operating System including object format, if it has switched
+	# to ELF recently (or will in the future) and ABI.
+	case "$UNAME_MACHINE_ARCH" in
+	    earm*)
+		os=netbsdelf
+		;;
+	    arm*|i386|m68k|ns32k|sh3*|sparc|vax)
+		eval "$set_cc_for_build"
+		if echo __ELF__ | $CC_FOR_BUILD -E - 2>/dev/null \
+			| grep -q __ELF__
+		then
+		    # Once all utilities can be ECOFF (netbsdecoff) or a.out (netbsdaout).
+		    # Return netbsd for either.  FIX?
+		    os=netbsd
+		else
+		    os=netbsdelf
+		fi
+		;;
+	    *)
+		os=netbsd
+		;;
+	esac
+	# Determine ABI tags.
+	case "$UNAME_MACHINE_ARCH" in
+	    earm*)
+		expr='s/^earmv[0-9]/-eabi/;s/eb$//'
+		abi=`echo "$UNAME_MACHINE_ARCH" | sed -e "$expr"`
+		;;
+	esac
+	# The OS release
+	# Debian GNU/NetBSD machines have a different userland, and
+	# thus, need a distinct triplet. However, they do not need
+	# kernel version information, so it can be replaced with a
+	# suitable tag, in the style of linux-gnu.
+	case "$UNAME_VERSION" in
+	    Debian*)
+		release='-gnu'
+		;;
+	    *)
+		release=`echo "$UNAME_RELEASE" | sed -e 's/[-_].*//' | cut -d. -f1,2`
+		;;
+	esac
+	# Since CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM:
+	# contains redundant information, the shorter form:
+	# CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM is used.
+	echo "$machine-${os}${release}${abi}"
+	exit ;;
+    *:Bitrig:*:*)
+	UNAME_MACHINE_ARCH=`arch | sed 's/Bitrig.//'`
+	echo "$UNAME_MACHINE_ARCH"-unknown-bitrig"$UNAME_RELEASE"
+	exit ;;
+    *:OpenBSD:*:*)
+	UNAME_MACHINE_ARCH=`arch | sed 's/OpenBSD.//'`
+	echo "$UNAME_MACHINE_ARCH"-unknown-openbsd"$UNAME_RELEASE"
+	exit ;;
+    *:LibertyBSD:*:*)
+	UNAME_MACHINE_ARCH=`arch | sed 's/^.*BSD\.//'`
+	echo "$UNAME_MACHINE_ARCH"-unknown-libertybsd"$UNAME_RELEASE"
+	exit ;;
+    *:MidnightBSD:*:*)
+	echo "$UNAME_MACHINE"-unknown-midnightbsd"$UNAME_RELEASE"
+	exit ;;
+    *:ekkoBSD:*:*)
+	echo "$UNAME_MACHINE"-unknown-ekkobsd"$UNAME_RELEASE"
+	exit ;;
+    *:SolidBSD:*:*)
+	echo "$UNAME_MACHINE"-unknown-solidbsd"$UNAME_RELEASE"
+	exit ;;
+    macppc:MirBSD:*:*)
+	echo powerpc-unknown-mirbsd"$UNAME_RELEASE"
+	exit ;;
+    *:MirBSD:*:*)
+	echo "$UNAME_MACHINE"-unknown-mirbsd"$UNAME_RELEASE"
+	exit ;;
+    *:Sortix:*:*)
+	echo "$UNAME_MACHINE"-unknown-sortix
+	exit ;;
+    *:Redox:*:*)
+	echo "$UNAME_MACHINE"-unknown-redox
+	exit ;;
+    mips:OSF1:*.*)
+        echo mips-dec-osf1
+        exit ;;
+    alpha:OSF1:*:*)
+	case $UNAME_RELEASE in
+	*4.0)
+		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $3}'`
+		;;
+	*5.*)
+		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $4}'`
+		;;
+	esac
+	# According to Compaq, /usr/sbin/psrinfo has been available on
+	# OSF/1 and Tru64 systems produced since 1995.  I hope that
+	# covers most systems running today.  This code pipes the CPU
+	# types through head -n 1, so we only detect the type of CPU 0.
+	ALPHA_CPU_TYPE=`/usr/sbin/psrinfo -v | sed -n -e 's/^  The alpha \(.*\) processor.*$/\1/p' | head -n 1`
+	case "$ALPHA_CPU_TYPE" in
+	    "EV4 (21064)")
+		UNAME_MACHINE=alpha ;;
+	    "EV4.5 (21064)")
+		UNAME_MACHINE=alpha ;;
+	    "LCA4 (21066/21068)")
+		UNAME_MACHINE=alpha ;;
+	    "EV5 (21164)")
+		UNAME_MACHINE=alphaev5 ;;
+	    "EV5.6 (21164A)")
+		UNAME_MACHINE=alphaev56 ;;
+	    "EV5.6 (21164PC)")
+		UNAME_MACHINE=alphapca56 ;;
+	    "EV5.7 (21164PC)")
+		UNAME_MACHINE=alphapca57 ;;
+	    "EV6 (21264)")
+		UNAME_MACHINE=alphaev6 ;;
+	    "EV6.7 (21264A)")
+		UNAME_MACHINE=alphaev67 ;;
+	    "EV6.8CB (21264C)")
+		UNAME_MACHINE=alphaev68 ;;
+	    "EV6.8AL (21264B)")
+		UNAME_MACHINE=alphaev68 ;;
+	    "EV6.8CX (21264D)")
+		UNAME_MACHINE=alphaev68 ;;
+	    "EV6.9A (21264/EV69A)")
+		UNAME_MACHINE=alphaev69 ;;
+	    "EV7 (21364)")
+		UNAME_MACHINE=alphaev7 ;;
+	    "EV7.9 (21364A)")
+		UNAME_MACHINE=alphaev79 ;;
+	esac
+	# A Pn.n version is a patched version.
+	# A Vn.n version is a released version.
+	# A Tn.n version is a released field test version.
+	# A Xn.n version is an unreleased experimental baselevel.
+	# 1.2 uses "1.2" for uname -r.
+	echo "$UNAME_MACHINE"-dec-osf"`echo "$UNAME_RELEASE" | sed -e 's/^[PVTX]//' | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz`"
+	# Reset EXIT trap before exiting to avoid spurious non-zero exit code.
+	exitcode=$?
+	trap '' 0
+	exit $exitcode ;;
+    Amiga*:UNIX_System_V:4.0:*)
+	echo m68k-unknown-sysv4
+	exit ;;
+    *:[Aa]miga[Oo][Ss]:*:*)
+	echo "$UNAME_MACHINE"-unknown-amigaos
+	exit ;;
+    *:[Mm]orph[Oo][Ss]:*:*)
+	echo "$UNAME_MACHINE"-unknown-morphos
+	exit ;;
+    *:OS/390:*:*)
+	echo i370-ibm-openedition
+	exit ;;
+    *:z/VM:*:*)
+	echo s390-ibm-zvmoe
+	exit ;;
+    *:OS400:*:*)
+	echo powerpc-ibm-os400
+	exit ;;
+    arm:RISC*:1.[012]*:*|arm:riscix:1.[012]*:*)
+	echo arm-acorn-riscix"$UNAME_RELEASE"
+	exit ;;
+    arm*:riscos:*:*|arm*:RISCOS:*:*)
+	echo arm-unknown-riscos
+	exit ;;
+    SR2?01:HI-UX/MPP:*:* | SR8000:HI-UX/MPP:*:*)
+	echo hppa1.1-hitachi-hiuxmpp
+	exit ;;
+    Pyramid*:OSx*:*:* | MIS*:OSx*:*:* | MIS*:SMP_DC-OSx*:*:*)
+	# akee@wpdis03.wpafb.af.mil (Earle F. Ake) contributed MIS and NILE.
+	if test "`(/bin/universe) 2>/dev/null`" = att ; then
+		echo pyramid-pyramid-sysv3
+	else
+		echo pyramid-pyramid-bsd
+	fi
+	exit ;;
+    NILE*:*:*:dcosx)
+	echo pyramid-pyramid-svr4
+	exit ;;
+    DRS?6000:unix:4.0:6*)
+	echo sparc-icl-nx6
+	exit ;;
+    DRS?6000:UNIX_SV:4.2*:7* | DRS?6000:isis:4.2*:7*)
+	case `/usr/bin/uname -p` in
+	    sparc) echo sparc-icl-nx7; exit ;;
+	esac ;;
+    s390x:SunOS:*:*)
+	echo "$UNAME_MACHINE"-ibm-solaris2"`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`"
+	exit ;;
+    sun4H:SunOS:5.*:*)
+	echo sparc-hal-solaris2"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	exit ;;
+    sun4*:SunOS:5.*:* | tadpole*:SunOS:5.*:*)
+	echo sparc-sun-solaris2"`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`"
+	exit ;;
+    i86pc:AuroraUX:5.*:* | i86xen:AuroraUX:5.*:*)
+	echo i386-pc-auroraux"$UNAME_RELEASE"
+	exit ;;
+    i86pc:SunOS:5.*:* | i86xen:SunOS:5.*:*)
+	eval "$set_cc_for_build"
+	SUN_ARCH=i386
+	# If there is a compiler, see if it is configured for 64-bit objects.
+	# Note that the Sun cc does not turn __LP64__ into 1 like gcc does.
+	# This test works for both compilers.
+	if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
+	    if (echo '#ifdef __amd64'; echo IS_64BIT_ARCH; echo '#endif') | \
+		(CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		grep IS_64BIT_ARCH >/dev/null
+	    then
+		SUN_ARCH=x86_64
+	    fi
+	fi
+	echo "$SUN_ARCH"-pc-solaris2"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	exit ;;
+    sun4*:SunOS:6*:*)
+	# According to config.sub, this is the proper way to canonicalize
+	# SunOS6.  Hard to guess exactly what SunOS6 will be like, but
+	# it's likely to be more like Solaris than SunOS4.
+	echo sparc-sun-solaris3"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	exit ;;
+    sun4*:SunOS:*:*)
+	case "`/usr/bin/arch -k`" in
+	    Series*|S4*)
+		UNAME_RELEASE=`uname -v`
+		;;
+	esac
+	# Japanese Language versions have a version number like `4.1.3-JL'.
+	echo sparc-sun-sunos"`echo "$UNAME_RELEASE"|sed -e 's/-/_/'`"
+	exit ;;
+    sun3*:SunOS:*:*)
+	echo m68k-sun-sunos"$UNAME_RELEASE"
+	exit ;;
+    sun*:*:4.2BSD:*)
+	UNAME_RELEASE=`(sed 1q /etc/motd | awk '{print substr($5,1,3)}') 2>/dev/null`
+	test "x$UNAME_RELEASE" = x && UNAME_RELEASE=3
+	case "`/bin/arch`" in
+	    sun3)
+		echo m68k-sun-sunos"$UNAME_RELEASE"
+		;;
+	    sun4)
+		echo sparc-sun-sunos"$UNAME_RELEASE"
+		;;
+	esac
+	exit ;;
+    aushp:SunOS:*:*)
+	echo sparc-auspex-sunos"$UNAME_RELEASE"
+	exit ;;
+    # The situation for MiNT is a little confusing.  The machine name
+    # can be virtually everything (everything which is not
+    # "atarist" or "atariste" at least should have a processor
+    # > m68000).  The system name ranges from "MiNT" over "FreeMiNT"
+    # to the lowercase version "mint" (or "freemint").  Finally
+    # the system name "TOS" denotes a system which is actually not
+    # MiNT.  But MiNT is downward compatible to TOS, so this should
+    # be no problem.
+    atarist[e]:*MiNT:*:* | atarist[e]:*mint:*:* | atarist[e]:*TOS:*:*)
+	echo m68k-atari-mint"$UNAME_RELEASE"
+	exit ;;
+    atari*:*MiNT:*:* | atari*:*mint:*:* | atarist[e]:*TOS:*:*)
+	echo m68k-atari-mint"$UNAME_RELEASE"
+	exit ;;
+    *falcon*:*MiNT:*:* | *falcon*:*mint:*:* | *falcon*:*TOS:*:*)
+	echo m68k-atari-mint"$UNAME_RELEASE"
+	exit ;;
+    milan*:*MiNT:*:* | milan*:*mint:*:* | *milan*:*TOS:*:*)
+	echo m68k-milan-mint"$UNAME_RELEASE"
+	exit ;;
+    hades*:*MiNT:*:* | hades*:*mint:*:* | *hades*:*TOS:*:*)
+	echo m68k-hades-mint"$UNAME_RELEASE"
+	exit ;;
+    *:*MiNT:*:* | *:*mint:*:* | *:*TOS:*:*)
+	echo m68k-unknown-mint"$UNAME_RELEASE"
+	exit ;;
+    m68k:machten:*:*)
+	echo m68k-apple-machten"$UNAME_RELEASE"
+	exit ;;
+    powerpc:machten:*:*)
+	echo powerpc-apple-machten"$UNAME_RELEASE"
+	exit ;;
+    RISC*:Mach:*:*)
+	echo mips-dec-mach_bsd4.3
+	exit ;;
+    RISC*:ULTRIX:*:*)
+	echo mips-dec-ultrix"$UNAME_RELEASE"
+	exit ;;
+    VAX*:ULTRIX*:*:*)
+	echo vax-dec-ultrix"$UNAME_RELEASE"
+	exit ;;
+    2020:CLIX:*:* | 2430:CLIX:*:*)
+	echo clipper-intergraph-clix"$UNAME_RELEASE"
+	exit ;;
+    mips:*:*:UMIPS | mips:*:*:RISCos)
+	eval "$set_cc_for_build"
+	sed 's/^	//' << EOF > "$dummy.c"
+#ifdef __cplusplus
+#include <stdio.h>  /* for printf() prototype */
+	int main (int argc, char *argv[]) {
+#else
+	int main (argc, argv) int argc; char *argv[]; {
+#endif
+	#if defined (host_mips) && defined (MIPSEB)
+	#if defined (SYSTYPE_SYSV)
+	  printf ("mips-mips-riscos%ssysv\\n", argv[1]); exit (0);
+	#endif
+	#if defined (SYSTYPE_SVR4)
+	  printf ("mips-mips-riscos%ssvr4\\n", argv[1]); exit (0);
+	#endif
+	#if defined (SYSTYPE_BSD43) || defined(SYSTYPE_BSD)
+	  printf ("mips-mips-riscos%sbsd\\n", argv[1]); exit (0);
+	#endif
+	#endif
+	  exit (-1);
+	}
+EOF
+	$CC_FOR_BUILD -o "$dummy" "$dummy.c" &&
+	  dummyarg=`echo "$UNAME_RELEASE" | sed -n 's/\([0-9]*\).*/\1/p'` &&
+	  SYSTEM_NAME=`"$dummy" "$dummyarg"` &&
+	    { echo "$SYSTEM_NAME"; exit; }
+	echo mips-mips-riscos"$UNAME_RELEASE"
+	exit ;;
+    Motorola:PowerMAX_OS:*:*)
+	echo powerpc-motorola-powermax
+	exit ;;
+    Motorola:*:4.3:PL8-*)
+	echo powerpc-harris-powermax
+	exit ;;
+    Night_Hawk:*:*:PowerMAX_OS | Synergy:PowerMAX_OS:*:*)
+	echo powerpc-harris-powermax
+	exit ;;
+    Night_Hawk:Power_UNIX:*:*)
+	echo powerpc-harris-powerunix
+	exit ;;
+    m88k:CX/UX:7*:*)
+	echo m88k-harris-cxux7
+	exit ;;
+    m88k:*:4*:R4*)
+	echo m88k-motorola-sysv4
+	exit ;;
+    m88k:*:3*:R3*)
+	echo m88k-motorola-sysv3
+	exit ;;
+    AViiON:dgux:*:*)
+	# DG/UX returns AViiON for all architectures
+	UNAME_PROCESSOR=`/usr/bin/uname -p`
+	if [ "$UNAME_PROCESSOR" = mc88100 ] || [ "$UNAME_PROCESSOR" = mc88110 ]
+	then
+	    if [ "$TARGET_BINARY_INTERFACE"x = m88kdguxelfx ] || \
+	       [ "$TARGET_BINARY_INTERFACE"x = x ]
+	    then
+		echo m88k-dg-dgux"$UNAME_RELEASE"
+	    else
+		echo m88k-dg-dguxbcs"$UNAME_RELEASE"
+	    fi
+	else
+	    echo i586-dg-dgux"$UNAME_RELEASE"
+	fi
+	exit ;;
+    M88*:DolphinOS:*:*)	# DolphinOS (SVR3)
+	echo m88k-dolphin-sysv3
+	exit ;;
+    M88*:*:R3*:*)
+	# Delta 88k system running SVR3
+	echo m88k-motorola-sysv3
+	exit ;;
+    XD88*:*:*:*) # Tektronix XD88 system running UTekV (SVR3)
+	echo m88k-tektronix-sysv3
+	exit ;;
+    Tek43[0-9][0-9]:UTek:*:*) # Tektronix 4300 system running UTek (BSD)
+	echo m68k-tektronix-bsd
+	exit ;;
+    *:IRIX*:*:*)
+	echo mips-sgi-irix"`echo "$UNAME_RELEASE"|sed -e 's/-/_/g'`"
+	exit ;;
+    ????????:AIX?:[12].1:2)   # AIX 2.2.1 or AIX 2.1.1 is RT/PC AIX.
+	echo romp-ibm-aix     # uname -m gives an 8 hex-code CPU id
+	exit ;;               # Note that: echo "'`uname -s`'" gives 'AIX '
+    i*86:AIX:*:*)
+	echo i386-ibm-aix
+	exit ;;
+    ia64:AIX:*:*)
+	if [ -x /usr/bin/oslevel ] ; then
+		IBM_REV=`/usr/bin/oslevel`
+	else
+		IBM_REV="$UNAME_VERSION.$UNAME_RELEASE"
+	fi
+	echo "$UNAME_MACHINE"-ibm-aix"$IBM_REV"
+	exit ;;
+    *:AIX:2:3)
+	if grep bos325 /usr/include/stdio.h >/dev/null 2>&1; then
+		eval "$set_cc_for_build"
+		sed 's/^		//' << EOF > "$dummy.c"
+		#include <sys/systemcfg.h>
+
+		main()
+			{
+			if (!__power_pc())
+				exit(1);
+			puts("powerpc-ibm-aix3.2.5");
+			exit(0);
+			}
+EOF
+		if $CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=`"$dummy"`
+		then
+			echo "$SYSTEM_NAME"
+		else
+			echo rs6000-ibm-aix3.2.5
+		fi
+	elif grep bos324 /usr/include/stdio.h >/dev/null 2>&1; then
+		echo rs6000-ibm-aix3.2.4
+	else
+		echo rs6000-ibm-aix3.2
+	fi
+	exit ;;
+    *:AIX:*:[4567])
+	IBM_CPU_ID=`/usr/sbin/lsdev -C -c processor -S available | sed 1q | awk '{ print $1 }'`
+	if /usr/sbin/lsattr -El "$IBM_CPU_ID" | grep ' POWER' >/dev/null 2>&1; then
+		IBM_ARCH=rs6000
+	else
+		IBM_ARCH=powerpc
+	fi
+	if [ -x /usr/bin/lslpp ] ; then
+		IBM_REV=`/usr/bin/lslpp -Lqc bos.rte.libc |
+			   awk -F: '{ print $3 }' | sed s/[0-9]*$/0/`
+	else
+		IBM_REV="$UNAME_VERSION.$UNAME_RELEASE"
+	fi
+	echo "$IBM_ARCH"-ibm-aix"$IBM_REV"
+	exit ;;
+    *:AIX:*:*)
+	echo rs6000-ibm-aix
+	exit ;;
+    ibmrt:4.4BSD:*|romp-ibm:4.4BSD:*)
+	echo romp-ibm-bsd4.4
+	exit ;;
+    ibmrt:*BSD:*|romp-ibm:BSD:*)            # covers RT/PC BSD and
+	echo romp-ibm-bsd"$UNAME_RELEASE"   # 4.3 with uname added to
+	exit ;;                             # report: romp-ibm BSD 4.3
+    *:BOSX:*:*)
+	echo rs6000-bull-bosx
+	exit ;;
+    DPX/2?00:B.O.S.:*:*)
+	echo m68k-bull-sysv3
+	exit ;;
+    9000/[34]??:4.3bsd:1.*:*)
+	echo m68k-hp-bsd
+	exit ;;
+    hp300:4.4BSD:*:* | 9000/[34]??:4.3bsd:2.*:*)
+	echo m68k-hp-bsd4.4
+	exit ;;
+    9000/[34678]??:HP-UX:*:*)
+	HPUX_REV=`echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//'`
+	case "$UNAME_MACHINE" in
+	    9000/31?)            HP_ARCH=m68000 ;;
+	    9000/[34]??)         HP_ARCH=m68k ;;
+	    9000/[678][0-9][0-9])
+		if [ -x /usr/bin/getconf ]; then
+		    sc_cpu_version=`/usr/bin/getconf SC_CPU_VERSION 2>/dev/null`
+		    sc_kernel_bits=`/usr/bin/getconf SC_KERNEL_BITS 2>/dev/null`
+		    case "$sc_cpu_version" in
+		      523) HP_ARCH=hppa1.0 ;; # CPU_PA_RISC1_0
+		      528) HP_ARCH=hppa1.1 ;; # CPU_PA_RISC1_1
+		      532)                      # CPU_PA_RISC2_0
+			case "$sc_kernel_bits" in
+			  32) HP_ARCH=hppa2.0n ;;
+			  64) HP_ARCH=hppa2.0w ;;
+			  '') HP_ARCH=hppa2.0 ;;   # HP-UX 10.20
+			esac ;;
+		    esac
+		fi
+		if [ "$HP_ARCH" = "" ]; then
+		    eval "$set_cc_for_build"
+		    sed 's/^		//' << EOF > "$dummy.c"
+
+		#define _HPUX_SOURCE
+		#include <stdlib.h>
+		#include <unistd.h>
+
+		int main ()
+		{
+		#if defined(_SC_KERNEL_BITS)
+		    long bits = sysconf(_SC_KERNEL_BITS);
+		#endif
+		    long cpu  = sysconf (_SC_CPU_VERSION);
+
+		    switch (cpu)
+			{
+			case CPU_PA_RISC1_0: puts ("hppa1.0"); break;
+			case CPU_PA_RISC1_1: puts ("hppa1.1"); break;
+			case CPU_PA_RISC2_0:
+		#if defined(_SC_KERNEL_BITS)
+			    switch (bits)
+				{
+				case 64: puts ("hppa2.0w"); break;
+				case 32: puts ("hppa2.0n"); break;
+				default: puts ("hppa2.0"); break;
+				} break;
+		#else  /* !defined(_SC_KERNEL_BITS) */
+			    puts ("hppa2.0"); break;
+		#endif
+			default: puts ("hppa1.0"); break;
+			}
+		    exit (0);
+		}
+EOF
+		    (CCOPTS="" $CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null) && HP_ARCH=`"$dummy"`
+		    test -z "$HP_ARCH" && HP_ARCH=hppa
+		fi ;;
+	esac
+	if [ "$HP_ARCH" = hppa2.0w ]
+	then
+	    eval "$set_cc_for_build"
+
+	    # hppa2.0w-hp-hpux* has a 64-bit kernel and a compiler generating
+	    # 32-bit code.  hppa64-hp-hpux* has the same kernel and a compiler
+	    # generating 64-bit code.  GNU and HP use different nomenclature:
+	    #
+	    # $ CC_FOR_BUILD=cc ./config.guess
+	    # => hppa2.0w-hp-hpux11.23
+	    # $ CC_FOR_BUILD="cc +DA2.0w" ./config.guess
+	    # => hppa64-hp-hpux11.23
+
+	    if echo __LP64__ | (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) |
+		grep -q __LP64__
+	    then
+		HP_ARCH=hppa2.0w
+	    else
+		HP_ARCH=hppa64
+	    fi
+	fi
+	echo "$HP_ARCH"-hp-hpux"$HPUX_REV"
+	exit ;;
+    ia64:HP-UX:*:*)
+	HPUX_REV=`echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//'`
+	echo ia64-hp-hpux"$HPUX_REV"
+	exit ;;
+    3050*:HI-UX:*:*)
+	eval "$set_cc_for_build"
+	sed 's/^	//' << EOF > "$dummy.c"
+	#include <unistd.h>
+	int
+	main ()
+	{
+	  long cpu = sysconf (_SC_CPU_VERSION);
+	  /* The order matters, because CPU_IS_HP_MC68K erroneously returns
+	     true for CPU_PA_RISC1_0.  CPU_IS_PA_RISC returns correct
+	     results, however.  */
+	  if (CPU_IS_PA_RISC (cpu))
+	    {
+	      switch (cpu)
+		{
+		  case CPU_PA_RISC1_0: puts ("hppa1.0-hitachi-hiuxwe2"); break;
+		  case CPU_PA_RISC1_1: puts ("hppa1.1-hitachi-hiuxwe2"); break;
+		  case CPU_PA_RISC2_0: puts ("hppa2.0-hitachi-hiuxwe2"); break;
+		  default: puts ("hppa-hitachi-hiuxwe2"); break;
+		}
+	    }
+	  else if (CPU_IS_HP_MC68K (cpu))
+	    puts ("m68k-hitachi-hiuxwe2");
+	  else puts ("unknown-hitachi-hiuxwe2");
+	  exit (0);
+	}
+EOF
+	$CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=`"$dummy"` &&
+		{ echo "$SYSTEM_NAME"; exit; }
+	echo unknown-hitachi-hiuxwe2
+	exit ;;
+    9000/7??:4.3bsd:*:* | 9000/8?[79]:4.3bsd:*:*)
+	echo hppa1.1-hp-bsd
+	exit ;;
+    9000/8??:4.3bsd:*:*)
+	echo hppa1.0-hp-bsd
+	exit ;;
+    *9??*:MPE/iX:*:* | *3000*:MPE/iX:*:*)
+	echo hppa1.0-hp-mpeix
+	exit ;;
+    hp7??:OSF1:*:* | hp8?[79]:OSF1:*:*)
+	echo hppa1.1-hp-osf
+	exit ;;
+    hp8??:OSF1:*:*)
+	echo hppa1.0-hp-osf
+	exit ;;
+    i*86:OSF1:*:*)
+	if [ -x /usr/sbin/sysversion ] ; then
+	    echo "$UNAME_MACHINE"-unknown-osf1mk
+	else
+	    echo "$UNAME_MACHINE"-unknown-osf1
+	fi
+	exit ;;
+    parisc*:Lites*:*:*)
+	echo hppa1.1-hp-lites
+	exit ;;
+    C1*:ConvexOS:*:* | convex:ConvexOS:C1*:*)
+	echo c1-convex-bsd
+	exit ;;
+    C2*:ConvexOS:*:* | convex:ConvexOS:C2*:*)
+	if getsysinfo -f scalar_acc
+	then echo c32-convex-bsd
+	else echo c2-convex-bsd
+	fi
+	exit ;;
+    C34*:ConvexOS:*:* | convex:ConvexOS:C34*:*)
+	echo c34-convex-bsd
+	exit ;;
+    C38*:ConvexOS:*:* | convex:ConvexOS:C38*:*)
+	echo c38-convex-bsd
+	exit ;;
+    C4*:ConvexOS:*:* | convex:ConvexOS:C4*:*)
+	echo c4-convex-bsd
+	exit ;;
+    CRAY*Y-MP:*:*:*)
+	echo ymp-cray-unicos"$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'
+	exit ;;
+    CRAY*[A-Z]90:*:*:*)
+	echo "$UNAME_MACHINE"-cray-unicos"$UNAME_RELEASE" \
+	| sed -e 's/CRAY.*\([A-Z]90\)/\1/' \
+	      -e y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/ \
+	      -e 's/\.[^.]*$/.X/'
+	exit ;;
+    CRAY*TS:*:*:*)
+	echo t90-cray-unicos"$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'
+	exit ;;
+    CRAY*T3E:*:*:*)
+	echo alphaev5-cray-unicosmk"$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'
+	exit ;;
+    CRAY*SV1:*:*:*)
+	echo sv1-cray-unicos"$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'
+	exit ;;
+    *:UNICOS/mp:*:*)
+	echo craynv-cray-unicosmp"$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'
+	exit ;;
+    F30[01]:UNIX_System_V:*:* | F700:UNIX_System_V:*:*)
+	FUJITSU_PROC=`uname -m | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz`
+	FUJITSU_SYS=`uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///'`
+	FUJITSU_REL=`echo "$UNAME_RELEASE" | sed -e 's/ /_/'`
+	echo "${FUJITSU_PROC}-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
+	exit ;;
+    5000:UNIX_System_V:4.*:*)
+	FUJITSU_SYS=`uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///'`
+	FUJITSU_REL=`echo "$UNAME_RELEASE" | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/ /_/'`
+	echo "sparc-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
+	exit ;;
+    i*86:BSD/386:*:* | i*86:BSD/OS:*:* | *:Ascend\ Embedded/OS:*:*)
+	echo "$UNAME_MACHINE"-pc-bsdi"$UNAME_RELEASE"
+	exit ;;
+    sparc*:BSD/OS:*:*)
+	echo sparc-unknown-bsdi"$UNAME_RELEASE"
+	exit ;;
+    *:BSD/OS:*:*)
+	echo "$UNAME_MACHINE"-unknown-bsdi"$UNAME_RELEASE"
+	exit ;;
+    *:FreeBSD:*:*)
+	UNAME_PROCESSOR=`/usr/bin/uname -p`
+	case "$UNAME_PROCESSOR" in
+	    amd64)
+		UNAME_PROCESSOR=x86_64 ;;
+	    i386)
+		UNAME_PROCESSOR=i586 ;;
+	esac
+	echo "$UNAME_PROCESSOR"-unknown-freebsd"`echo "$UNAME_RELEASE"|sed -e 's/[-(].*//'`"
+	exit ;;
+    i*:CYGWIN*:*)
+	echo "$UNAME_MACHINE"-pc-cygwin
+	exit ;;
+    *:MINGW64*:*)
+	echo "$UNAME_MACHINE"-pc-mingw64
+	exit ;;
+    *:MINGW*:*)
+	echo "$UNAME_MACHINE"-pc-mingw32
+	exit ;;
+    *:MSYS*:*)
+	echo "$UNAME_MACHINE"-pc-msys
+	exit ;;
+    i*:PW*:*)
+	echo "$UNAME_MACHINE"-pc-pw32
+	exit ;;
+    *:Interix*:*)
+	case "$UNAME_MACHINE" in
+	    x86)
+		echo i586-pc-interix"$UNAME_RELEASE"
+		exit ;;
+	    authenticamd | genuineintel | EM64T)
+		echo x86_64-unknown-interix"$UNAME_RELEASE"
+		exit ;;
+	    IA64)
+		echo ia64-unknown-interix"$UNAME_RELEASE"
+		exit ;;
+	esac ;;
+    i*:UWIN*:*)
+	echo "$UNAME_MACHINE"-pc-uwin
+	exit ;;
+    amd64:CYGWIN*:*:* | x86_64:CYGWIN*:*:*)
+	echo x86_64-unknown-cygwin
+	exit ;;
+    prep*:SunOS:5.*:*)
+	echo powerpcle-unknown-solaris2"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	exit ;;
+    *:GNU:*:*)
+	# the GNU system
+	echo "`echo "$UNAME_MACHINE"|sed -e 's,[-/].*$,,'`-unknown-$LIBC`echo "$UNAME_RELEASE"|sed -e 's,/.*$,,'`"
+	exit ;;
+    *:GNU/*:*:*)
+	# other systems with GNU libc and userland
+	echo "$UNAME_MACHINE-unknown-`echo "$UNAME_SYSTEM" | sed 's,^[^/]*/,,' | tr "[:upper:]" "[:lower:]"``echo "$UNAME_RELEASE"|sed -e 's/[-(].*//'`-$LIBC"
+	exit ;;
+    i*86:Minix:*:*)
+	echo "$UNAME_MACHINE"-pc-minix
+	exit ;;
+    aarch64:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    aarch64_be:Linux:*:*)
+	UNAME_MACHINE=aarch64_be
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    alpha:Linux:*:*)
+	case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo` in
+	  EV5)   UNAME_MACHINE=alphaev5 ;;
+	  EV56)  UNAME_MACHINE=alphaev56 ;;
+	  PCA56) UNAME_MACHINE=alphapca56 ;;
+	  PCA57) UNAME_MACHINE=alphapca56 ;;
+	  EV6)   UNAME_MACHINE=alphaev6 ;;
+	  EV67)  UNAME_MACHINE=alphaev67 ;;
+	  EV68*) UNAME_MACHINE=alphaev68 ;;
+	esac
+	objdump --private-headers /bin/sh | grep -q ld.so.1
+	if test "$?" = 0 ; then LIBC=gnulibc1 ; fi
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    arc:Linux:*:* | arceb:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    arm*:Linux:*:*)
+	eval "$set_cc_for_build"
+	if echo __ARM_EABI__ | $CC_FOR_BUILD -E - 2>/dev/null \
+	    | grep -q __ARM_EABI__
+	then
+	    echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	else
+	    if echo __ARM_PCS_VFP | $CC_FOR_BUILD -E - 2>/dev/null \
+		| grep -q __ARM_PCS_VFP
+	    then
+		echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"eabi
+	    else
+		echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"eabihf
+	    fi
+	fi
+	exit ;;
+    avr32*:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    cris:Linux:*:*)
+	echo "$UNAME_MACHINE"-axis-linux-"$LIBC"
+	exit ;;
+    crisv32:Linux:*:*)
+	echo "$UNAME_MACHINE"-axis-linux-"$LIBC"
+	exit ;;
+    e2k:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    frv:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    hexagon:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    i*86:Linux:*:*)
+	echo "$UNAME_MACHINE"-pc-linux-"$LIBC"
+	exit ;;
+    ia64:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    k1om:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    m32r*:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    m68*:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    mips:Linux:*:* | mips64:Linux:*:*)
+	eval "$set_cc_for_build"
+	sed 's/^	//' << EOF > "$dummy.c"
+	#undef CPU
+	#undef ${UNAME_MACHINE}
+	#undef ${UNAME_MACHINE}el
+	#if defined(__MIPSEL__) || defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL)
+	CPU=${UNAME_MACHINE}el
+	#else
+	#if defined(__MIPSEB__) || defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB)
+	CPU=${UNAME_MACHINE}
+	#else
+	CPU=
+	#endif
+	#endif
+EOF
+	eval "`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^CPU'`"
+	test "x$CPU" != x && { echo "$CPU-unknown-linux-$LIBC"; exit; }
+	;;
+    mips64el:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    openrisc*:Linux:*:*)
+	echo or1k-unknown-linux-"$LIBC"
+	exit ;;
+    or32:Linux:*:* | or1k*:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    padre:Linux:*:*)
+	echo sparc-unknown-linux-"$LIBC"
+	exit ;;
+    parisc64:Linux:*:* | hppa64:Linux:*:*)
+	echo hppa64-unknown-linux-"$LIBC"
+	exit ;;
+    parisc:Linux:*:* | hppa:Linux:*:*)
+	# Look for CPU level
+	case `grep '^cpu[^a-z]*:' /proc/cpuinfo 2>/dev/null | cut -d' ' -f2` in
+	  PA7*) echo hppa1.1-unknown-linux-"$LIBC" ;;
+	  PA8*) echo hppa2.0-unknown-linux-"$LIBC" ;;
+	  *)    echo hppa-unknown-linux-"$LIBC" ;;
+	esac
+	exit ;;
+    ppc64:Linux:*:*)
+	echo powerpc64-unknown-linux-"$LIBC"
+	exit ;;
+    ppc:Linux:*:*)
+	echo powerpc-unknown-linux-"$LIBC"
+	exit ;;
+    ppc64le:Linux:*:*)
+	echo powerpc64le-unknown-linux-"$LIBC"
+	exit ;;
+    ppcle:Linux:*:*)
+	echo powerpcle-unknown-linux-"$LIBC"
+	exit ;;
+    riscv32:Linux:*:* | riscv64:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    s390:Linux:*:* | s390x:Linux:*:*)
+	echo "$UNAME_MACHINE"-ibm-linux-"$LIBC"
+	exit ;;
+    sh64*:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    sh*:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    sparc:Linux:*:* | sparc64:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    tile*:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    vax:Linux:*:*)
+	echo "$UNAME_MACHINE"-dec-linux-"$LIBC"
+	exit ;;
+    x86_64:Linux:*:*)
+	echo "$UNAME_MACHINE"-pc-linux-"$LIBC"
+	exit ;;
+    xtensa*:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
+    i*86:DYNIX/ptx:4*:*)
+	# ptx 4.0 does uname -s correctly, with DYNIX/ptx in there.
+	# earlier versions are messed up and put the nodename in both
+	# sysname and nodename.
+	echo i386-sequent-sysv4
+	exit ;;
+    i*86:UNIX_SV:4.2MP:2.*)
+	# Unixware is an offshoot of SVR4, but it has its own version
+	# number series starting with 2...
+	# I am not positive that other SVR4 systems won't match this,
+	# I just have to hope.  -- rms.
+	# Use sysv4.2uw... so that sysv4* matches it.
+	echo "$UNAME_MACHINE"-pc-sysv4.2uw"$UNAME_VERSION"
+	exit ;;
+    i*86:OS/2:*:*)
+	# If we were able to find `uname', then EMX Unix compatibility
+	# is probably installed.
+	echo "$UNAME_MACHINE"-pc-os2-emx
+	exit ;;
+    i*86:XTS-300:*:STOP)
+	echo "$UNAME_MACHINE"-unknown-stop
+	exit ;;
+    i*86:atheos:*:*)
+	echo "$UNAME_MACHINE"-unknown-atheos
+	exit ;;
+    i*86:syllable:*:*)
+	echo "$UNAME_MACHINE"-pc-syllable
+	exit ;;
+    i*86:LynxOS:2.*:* | i*86:LynxOS:3.[01]*:* | i*86:LynxOS:4.[02]*:*)
+	echo i386-unknown-lynxos"$UNAME_RELEASE"
+	exit ;;
+    i*86:*DOS:*:*)
+	echo "$UNAME_MACHINE"-pc-msdosdjgpp
+	exit ;;
+    i*86:*:4.*:*)
+	UNAME_REL=`echo "$UNAME_RELEASE" | sed 's/\/MP$//'`
+	if grep Novell /usr/include/link.h >/dev/null 2>/dev/null; then
+		echo "$UNAME_MACHINE"-univel-sysv"$UNAME_REL"
+	else
+		echo "$UNAME_MACHINE"-pc-sysv"$UNAME_REL"
+	fi
+	exit ;;
+    i*86:*:5:[678]*)
+	# UnixWare 7.x, OpenUNIX and OpenServer 6.
+	case `/bin/uname -X | grep "^Machine"` in
+	    *486*)	     UNAME_MACHINE=i486 ;;
+	    *Pentium)	     UNAME_MACHINE=i586 ;;
+	    *Pent*|*Celeron) UNAME_MACHINE=i686 ;;
+	esac
+	echo "$UNAME_MACHINE-unknown-sysv${UNAME_RELEASE}${UNAME_SYSTEM}{$UNAME_VERSION}"
+	exit ;;
+    i*86:*:3.2:*)
+	if test -f /usr/options/cb.name; then
+		UNAME_REL=`sed -n 's/.*Version //p' </usr/options/cb.name`
+		echo "$UNAME_MACHINE"-pc-isc"$UNAME_REL"
+	elif /bin/uname -X 2>/dev/null >/dev/null ; then
+		UNAME_REL=`(/bin/uname -X|grep Release|sed -e 's/.*= //')`
+		(/bin/uname -X|grep i80486 >/dev/null) && UNAME_MACHINE=i486
+		(/bin/uname -X|grep '^Machine.*Pentium' >/dev/null) \
+			&& UNAME_MACHINE=i586
+		(/bin/uname -X|grep '^Machine.*Pent *II' >/dev/null) \
+			&& UNAME_MACHINE=i686
+		(/bin/uname -X|grep '^Machine.*Pentium Pro' >/dev/null) \
+			&& UNAME_MACHINE=i686
+		echo "$UNAME_MACHINE"-pc-sco"$UNAME_REL"
+	else
+		echo "$UNAME_MACHINE"-pc-sysv32
+	fi
+	exit ;;
+    pc:*:*:*)
+	# Left here for compatibility:
+	# uname -m prints for DJGPP always 'pc', but it prints nothing about
+	# the processor, so we play safe by assuming i586.
+	# Note: whatever this is, it MUST be the same as what config.sub
+	# prints for the "djgpp" host, or else GDB configure will decide that
+	# this is a cross-build.
+	echo i586-pc-msdosdjgpp
+	exit ;;
+    Intel:Mach:3*:*)
+	echo i386-pc-mach3
+	exit ;;
+    paragon:*:*:*)
+	echo i860-intel-osf1
+	exit ;;
+    i860:*:4.*:*) # i860-SVR4
+	if grep Stardent /usr/include/sys/uadmin.h >/dev/null 2>&1 ; then
+	  echo i860-stardent-sysv"$UNAME_RELEASE" # Stardent Vistra i860-SVR4
+	else # Add other i860-SVR4 vendors below as they are discovered.
+	  echo i860-unknown-sysv"$UNAME_RELEASE"  # Unknown i860-SVR4
+	fi
+	exit ;;
+    mini*:CTIX:SYS*5:*)
+	# "miniframe"
+	echo m68010-convergent-sysv
+	exit ;;
+    mc68k:UNIX:SYSTEM5:3.51m)
+	echo m68k-convergent-sysv
+	exit ;;
+    M680?0:D-NIX:5.3:*)
+	echo m68k-diab-dnix
+	exit ;;
+    M68*:*:R3V[5678]*:*)
+	test -r /sysV68 && { echo 'm68k-motorola-sysv'; exit; } ;;
+    3[345]??:*:4.0:3.0 | 3[34]??A:*:4.0:3.0 | 3[34]??,*:*:4.0:3.0 | 3[34]??/*:*:4.0:3.0 | 4400:*:4.0:3.0 | 4850:*:4.0:3.0 | SKA40:*:4.0:3.0 | SDS2:*:4.0:3.0 | SHG2:*:4.0:3.0 | S7501*:*:4.0:3.0)
+	OS_REL=''
+	test -r /etc/.relid \
+	&& OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
+	  && { echo i486-ncr-sysv4.3"$OS_REL"; exit; }
+	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
+	  && { echo i586-ncr-sysv4.3"$OS_REL"; exit; } ;;
+    3[34]??:*:4.0:* | 3[34]??,*:*:4.0:*)
+	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
+	  && { echo i486-ncr-sysv4; exit; } ;;
+    NCR*:*:4.2:* | MPRAS*:*:4.2:*)
+	OS_REL='.3'
+	test -r /etc/.relid \
+	    && OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
+	    && { echo i486-ncr-sysv4.3"$OS_REL"; exit; }
+	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
+	    && { echo i586-ncr-sysv4.3"$OS_REL"; exit; }
+	/bin/uname -p 2>/dev/null | /bin/grep pteron >/dev/null \
+	    && { echo i586-ncr-sysv4.3"$OS_REL"; exit; } ;;
+    m68*:LynxOS:2.*:* | m68*:LynxOS:3.0*:*)
+	echo m68k-unknown-lynxos"$UNAME_RELEASE"
+	exit ;;
+    mc68030:UNIX_System_V:4.*:*)
+	echo m68k-atari-sysv4
+	exit ;;
+    TSUNAMI:LynxOS:2.*:*)
+	echo sparc-unknown-lynxos"$UNAME_RELEASE"
+	exit ;;
+    rs6000:LynxOS:2.*:*)
+	echo rs6000-unknown-lynxos"$UNAME_RELEASE"
+	exit ;;
+    PowerPC:LynxOS:2.*:* | PowerPC:LynxOS:3.[01]*:* | PowerPC:LynxOS:4.[02]*:*)
+	echo powerpc-unknown-lynxos"$UNAME_RELEASE"
+	exit ;;
+    SM[BE]S:UNIX_SV:*:*)
+	echo mips-dde-sysv"$UNAME_RELEASE"
+	exit ;;
+    RM*:ReliantUNIX-*:*:*)
+	echo mips-sni-sysv4
+	exit ;;
+    RM*:SINIX-*:*:*)
+	echo mips-sni-sysv4
+	exit ;;
+    *:SINIX-*:*:*)
+	if uname -p 2>/dev/null >/dev/null ; then
+		UNAME_MACHINE=`(uname -p) 2>/dev/null`
+		echo "$UNAME_MACHINE"-sni-sysv4
+	else
+		echo ns32k-sni-sysv
+	fi
+	exit ;;
+    PENTIUM:*:4.0*:*)	# Unisys `ClearPath HMP IX 4000' SVR4/MP effort
+			# says <Richard.M.Bartel@ccMail.Census.GOV>
+	echo i586-unisys-sysv4
+	exit ;;
+    *:UNIX_System_V:4*:FTX*)
+	# From Gerald Hewes <hewes@openmarket.com>.
+	# How about differentiating between stratus architectures? -djm
+	echo hppa1.1-stratus-sysv4
+	exit ;;
+    *:*:*:FTX*)
+	# From seanf@swdc.stratus.com.
+	echo i860-stratus-sysv4
+	exit ;;
+    i*86:VOS:*:*)
+	# From Paul.Green@stratus.com.
+	echo "$UNAME_MACHINE"-stratus-vos
+	exit ;;
+    *:VOS:*:*)
+	# From Paul.Green@stratus.com.
+	echo hppa1.1-stratus-vos
+	exit ;;
+    mc68*:A/UX:*:*)
+	echo m68k-apple-aux"$UNAME_RELEASE"
+	exit ;;
+    news*:NEWS-OS:6*:*)
+	echo mips-sony-newsos6
+	exit ;;
+    R[34]000:*System_V*:*:* | R4000:UNIX_SYSV:*:* | R*000:UNIX_SV:*:*)
+	if [ -d /usr/nec ]; then
+		echo mips-nec-sysv"$UNAME_RELEASE"
+	else
+		echo mips-unknown-sysv"$UNAME_RELEASE"
+	fi
+	exit ;;
+    BeBox:BeOS:*:*)	# BeOS running on hardware made by Be, PPC only.
+	echo powerpc-be-beos
+	exit ;;
+    BeMac:BeOS:*:*)	# BeOS running on Mac or Mac clone, PPC only.
+	echo powerpc-apple-beos
+	exit ;;
+    BePC:BeOS:*:*)	# BeOS running on Intel PC compatible.
+	echo i586-pc-beos
+	exit ;;
+    BePC:Haiku:*:*)	# Haiku running on Intel PC compatible.
+	echo i586-pc-haiku
+	exit ;;
+    x86_64:Haiku:*:*)
+	echo x86_64-unknown-haiku
+	exit ;;
+    SX-4:SUPER-UX:*:*)
+	echo sx4-nec-superux"$UNAME_RELEASE"
+	exit ;;
+    SX-5:SUPER-UX:*:*)
+	echo sx5-nec-superux"$UNAME_RELEASE"
+	exit ;;
+    SX-6:SUPER-UX:*:*)
+	echo sx6-nec-superux"$UNAME_RELEASE"
+	exit ;;
+    SX-7:SUPER-UX:*:*)
+	echo sx7-nec-superux"$UNAME_RELEASE"
+	exit ;;
+    SX-8:SUPER-UX:*:*)
+	echo sx8-nec-superux"$UNAME_RELEASE"
+	exit ;;
+    SX-8R:SUPER-UX:*:*)
+	echo sx8r-nec-superux"$UNAME_RELEASE"
+	exit ;;
+    SX-ACE:SUPER-UX:*:*)
+	echo sxace-nec-superux"$UNAME_RELEASE"
+	exit ;;
+    Power*:Rhapsody:*:*)
+	echo powerpc-apple-rhapsody"$UNAME_RELEASE"
+	exit ;;
+    *:Rhapsody:*:*)
+	echo "$UNAME_MACHINE"-apple-rhapsody"$UNAME_RELEASE"
+	exit ;;
+    *:Darwin:*:*)
+	UNAME_PROCESSOR=`uname -p` || UNAME_PROCESSOR=unknown
+	eval "$set_cc_for_build"
+	if test "$UNAME_PROCESSOR" = unknown ; then
+	    UNAME_PROCESSOR=powerpc
+	fi
+	if test "`echo "$UNAME_RELEASE" | sed -e 's/\..*//'`" -le 10 ; then
+	    if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
+		if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
+		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		       grep IS_64BIT_ARCH >/dev/null
+		then
+		    case $UNAME_PROCESSOR in
+			i386) UNAME_PROCESSOR=x86_64 ;;
+			powerpc) UNAME_PROCESSOR=powerpc64 ;;
+		    esac
+		fi
+		# On 10.4-10.6 one might compile for PowerPC via gcc -arch ppc
+		if (echo '#ifdef __POWERPC__'; echo IS_PPC; echo '#endif') | \
+		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		       grep IS_PPC >/dev/null
+		then
+		    UNAME_PROCESSOR=powerpc
+		fi
+	    fi
+	elif test "$UNAME_PROCESSOR" = i386 ; then
+	    # Avoid executing cc on OS X 10.9, as it ships with a stub
+	    # that puts up a graphical alert prompting to install
+	    # developer tools.  Any system running Mac OS X 10.7 or
+	    # later (Darwin 11 and later) is required to have a 64-bit
+	    # processor. This is not true of the ARM version of Darwin
+	    # that Apple uses in portable devices.
+	    UNAME_PROCESSOR=x86_64
+	fi
+	echo "$UNAME_PROCESSOR"-apple-darwin"$UNAME_RELEASE"
+	exit ;;
+    *:procnto*:*:* | *:QNX:[0123456789]*:*)
+	UNAME_PROCESSOR=`uname -p`
+	if test "$UNAME_PROCESSOR" = x86; then
+		UNAME_PROCESSOR=i386
+		UNAME_MACHINE=pc
+	fi
+	echo "$UNAME_PROCESSOR"-"$UNAME_MACHINE"-nto-qnx"$UNAME_RELEASE"
+	exit ;;
+    *:QNX:*:4*)
+	echo i386-pc-qnx
+	exit ;;
+    NEO-*:NONSTOP_KERNEL:*:*)
+	echo neo-tandem-nsk"$UNAME_RELEASE"
+	exit ;;
+    NSE-*:NONSTOP_KERNEL:*:*)
+	echo nse-tandem-nsk"$UNAME_RELEASE"
+	exit ;;
+    NSR-*:NONSTOP_KERNEL:*:*)
+	echo nsr-tandem-nsk"$UNAME_RELEASE"
+	exit ;;
+    NSV-*:NONSTOP_KERNEL:*:*)
+	echo nsv-tandem-nsk"$UNAME_RELEASE"
+	exit ;;
+    NSX-*:NONSTOP_KERNEL:*:*)
+	echo nsx-tandem-nsk"$UNAME_RELEASE"
+	exit ;;
+    *:NonStop-UX:*:*)
+	echo mips-compaq-nonstopux
+	exit ;;
+    BS2000:POSIX*:*:*)
+	echo bs2000-siemens-sysv
+	exit ;;
+    DS/*:UNIX_System_V:*:*)
+	echo "$UNAME_MACHINE"-"$UNAME_SYSTEM"-"$UNAME_RELEASE"
+	exit ;;
+    *:Plan9:*:*)
+	# "uname -m" is not consistent, so use $cputype instead. 386
+	# is converted to i386 for consistency with other x86
+	# operating systems.
+	if test "$cputype" = 386; then
+	    UNAME_MACHINE=i386
+	else
+	    UNAME_MACHINE="$cputype"
+	fi
+	echo "$UNAME_MACHINE"-unknown-plan9
+	exit ;;
+    *:TOPS-10:*:*)
+	echo pdp10-unknown-tops10
+	exit ;;
+    *:TENEX:*:*)
+	echo pdp10-unknown-tenex
+	exit ;;
+    KS10:TOPS-20:*:* | KL10:TOPS-20:*:* | TYPE4:TOPS-20:*:*)
+	echo pdp10-dec-tops20
+	exit ;;
+    XKL-1:TOPS-20:*:* | TYPE5:TOPS-20:*:*)
+	echo pdp10-xkl-tops20
+	exit ;;
+    *:TOPS-20:*:*)
+	echo pdp10-unknown-tops20
+	exit ;;
+    *:ITS:*:*)
+	echo pdp10-unknown-its
+	exit ;;
+    SEI:*:*:SEIUX)
+	echo mips-sei-seiux"$UNAME_RELEASE"
+	exit ;;
+    *:DragonFly:*:*)
+	echo "$UNAME_MACHINE"-unknown-dragonfly"`echo "$UNAME_RELEASE"|sed -e 's/[-(].*//'`"
+	exit ;;
+    *:*VMS:*:*)
+	UNAME_MACHINE=`(uname -p) 2>/dev/null`
+	case "$UNAME_MACHINE" in
+	    A*) echo alpha-dec-vms ; exit ;;
+	    I*) echo ia64-dec-vms ; exit ;;
+	    V*) echo vax-dec-vms ; exit ;;
+	esac ;;
+    *:XENIX:*:SysV)
+	echo i386-pc-xenix
+	exit ;;
+    i*86:skyos:*:*)
+	echo "$UNAME_MACHINE"-pc-skyos"`echo "$UNAME_RELEASE" | sed -e 's/ .*$//'`"
+	exit ;;
+    i*86:rdos:*:*)
+	echo "$UNAME_MACHINE"-pc-rdos
+	exit ;;
+    i*86:AROS:*:*)
+	echo "$UNAME_MACHINE"-pc-aros
+	exit ;;
+    x86_64:VMkernel:*:*)
+	echo "$UNAME_MACHINE"-unknown-esx
+	exit ;;
+    amd64:Isilon\ OneFS:*:*)
+	echo x86_64-unknown-onefs
+	exit ;;
+esac
+
+echo "$0: unable to guess system type" >&2
+
+case "$UNAME_MACHINE:$UNAME_SYSTEM" in
+    mips:Linux | mips64:Linux)
+	# If we got here on MIPS GNU/Linux, output extra information.
+	cat >&2 <<EOF
+
+NOTE: MIPS GNU/Linux systems require a C compiler to fully recognize
+the system type. Please install a C compiler and try again.
+EOF
+	;;
+esac
+
+cat >&2 <<EOF
+
+This script (version $timestamp), has failed to recognize the
+operating system you are using. If your script is old, overwrite *all*
+copies of config.guess and config.sub with the latest versions from:
+
+  https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
+and
+  https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub
+
+If $0 has already been updated, send the following data and any
+information you think might be pertinent to config-patches@gnu.org to
+provide the necessary information to handle your system.
+
+config.guess timestamp = $timestamp
+
+uname -m = `(uname -m) 2>/dev/null || echo unknown`
+uname -r = `(uname -r) 2>/dev/null || echo unknown`
+uname -s = `(uname -s) 2>/dev/null || echo unknown`
+uname -v = `(uname -v) 2>/dev/null || echo unknown`
+
+/usr/bin/uname -p = `(/usr/bin/uname -p) 2>/dev/null`
+/bin/uname -X     = `(/bin/uname -X) 2>/dev/null`
+
+hostinfo               = `(hostinfo) 2>/dev/null`
+/bin/universe          = `(/bin/universe) 2>/dev/null`
+/usr/bin/arch -k       = `(/usr/bin/arch -k) 2>/dev/null`
+/bin/arch              = `(/bin/arch) 2>/dev/null`
+/usr/bin/oslevel       = `(/usr/bin/oslevel) 2>/dev/null`
+/usr/convex/getsysinfo = `(/usr/convex/getsysinfo) 2>/dev/null`
+
+UNAME_MACHINE = "$UNAME_MACHINE"
+UNAME_RELEASE = "$UNAME_RELEASE"
+UNAME_SYSTEM  = "$UNAME_SYSTEM"
+UNAME_VERSION = "$UNAME_VERSION"
+EOF
+
+exit 1
+
+# Local variables:
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "timestamp='"
+# time-stamp-format: "%:y-%02m-%02d"
+# time-stamp-end: "'"
+# End:
diff --git a/extern/libpng/config.h.in b/extern/libpng/config.h.in
new file mode 100644
index 0000000000..2931048bf4
--- /dev/null
+++ b/extern/libpng/config.h.in
@@ -0,0 +1,126 @@
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#undef HAVE_DLFCN_H
+
+/* Define to 1 if you have the `feenableexcept' function. */
+#undef HAVE_FEENABLEEXCEPT
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#undef HAVE_INTTYPES_H
+
+/* Define to 1 if you have the `m' library (-lm). */
+#undef HAVE_LIBM
+
+/* Define to 1 if you have the `z' library (-lz). */
+#undef HAVE_LIBZ
+
+/* Define to 1 if you have the <memory.h> header file. */
+#undef HAVE_MEMORY_H
+
+/* Define to 1 if you have the `pow' function. */
+#undef HAVE_POW
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#undef HAVE_STDINT_H
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#undef HAVE_STDLIB_H
+
+/* Define to 1 if you have the <strings.h> header file. */
+#undef HAVE_STRINGS_H
+
+/* Define to 1 if you have the <string.h> header file. */
+#undef HAVE_STRING_H
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#undef HAVE_SYS_STAT_H
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#undef HAVE_SYS_TYPES_H
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#undef HAVE_UNISTD_H
+
+/* Define to the sub-directory where libtool stores uninstalled libraries. */
+#undef LT_OBJDIR
+
+/* Name of package */
+#undef PACKAGE
+
+/* Define to the address where bug reports for this package should be sent. */
+#undef PACKAGE_BUGREPORT
+
+/* Define to the full name of this package. */
+#undef PACKAGE_NAME
+
+/* Define to the full name and version of this package. */
+#undef PACKAGE_STRING
+
+/* Define to the one symbol short name of this package. */
+#undef PACKAGE_TARNAME
+
+/* Define to the home page for this package. */
+#undef PACKAGE_URL
+
+/* Define to the version of this package. */
+#undef PACKAGE_VERSION
+
+/* Turn on ARM Neon optimizations at run-time */
+#undef PNG_ARM_NEON_API_SUPPORTED
+
+/* Check for ARM Neon support at run-time */
+#undef PNG_ARM_NEON_CHECK_SUPPORTED
+
+/* Enable ARM Neon optimizations */
+#undef PNG_ARM_NEON_OPT
+
+/* Enable Intel SSE optimizations */
+#undef PNG_INTEL_SSE_OPT
+
+/* Turn on MIPS MSA optimizations at run-time */
+#undef PNG_MIPS_MSA_API_SUPPORTED
+
+/* Check for MIPS MSA support at run-time */
+#undef PNG_MIPS_MSA_CHECK_SUPPORTED
+
+/* Enable MIPS MSA optimizations */
+#undef PNG_MIPS_MSA_OPT
+
+/* Turn on POWERPC VSX optimizations at run-time */
+#undef PNG_POWERPC_VSX_API_SUPPORTED
+
+/* Check for POWERPC VSX support at run-time */
+#undef PNG_POWERPC_VSX_CHECK_SUPPORTED
+
+/* Enable POWERPC VSX optimizations */
+#undef PNG_POWERPC_VSX_OPT
+
+/* Define to 1 if you have the ANSI C header files. */
+#undef STDC_HEADERS
+
+/* Define to 1 if your <sys/time.h> declares `struct tm'. */
+#undef TM_IN_SYS_TIME
+
+/* Version number of package */
+#undef VERSION
+
+/* Define to empty if `const' does not conform to ANSI C. */
+#undef const
+
+/* Define to the equivalent of the C99 'restrict' keyword, or to
+   nothing if this is not supported.  Do not define if restrict is
+   supported directly.  */
+#undef restrict
+/* Work around a bug in Sun C++: it does not support _Restrict or
+   __restrict__, even though the corresponding Sun C compiler ends up with
+   "#define restrict _Restrict" or "#define restrict __restrict__" in the
+   previous line.  Perhaps some future version of Sun C++ will work with
+   restrict; if so, hopefully it defines __RESTRICT like Sun C does.  */
+#if defined __SUNPRO_CC && !defined __RESTRICT
+# define _Restrict
+# define __restrict__
+#endif
+
+/* Define to `unsigned int' if <sys/types.h> does not define. */
+#undef size_t
diff --git a/extern/libpng/config.sub b/extern/libpng/config.sub
new file mode 100755
index 0000000000..9ccf09a7a3
--- /dev/null
+++ b/extern/libpng/config.sub
@@ -0,0 +1,1801 @@
+#! /bin/sh
+# Configuration validation subroutine script.
+#   Copyright 1992-2018 Free Software Foundation, Inc.
+
+timestamp='2018-03-08'
+
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, see <https://www.gnu.org/licenses/>.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that
+# program.  This Exception is an additional permission under section 7
+# of the GNU General Public License, version 3 ("GPLv3").
+
+
+# Please send patches to <config-patches@gnu.org>.
+#
+# Configuration subroutine to validate and canonicalize a configuration type.
+# Supply the specified configuration type as an argument.
+# If it is invalid, we print an error message on stderr and exit with code 1.
+# Otherwise, we print the canonical config type on stdout and succeed.
+
+# You can get the latest version of this script from:
+# https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub
+
+# This file is supposed to be the same for all GNU packages
+# and recognize all the CPU types, system types and aliases
+# that are meaningful with *any* GNU software.
+# Each package is responsible for reporting which valid configurations
+# it does not support.  The user should be able to distinguish
+# a failure to support a valid configuration from a meaningless
+# configuration.
+
+# The goal of this file is to map all the various variations of a given
+# machine specification into a single specification in the form:
+#	CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM
+# or in some cases, the newer four-part form:
+#	CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM
+# It is wrong to echo any other type of specification.
+
+me=`echo "$0" | sed -e 's,.*/,,'`
+
+usage="\
+Usage: $0 [OPTION] CPU-MFR-OPSYS or ALIAS
+
+Canonicalize a configuration name.
+
+Options:
+  -h, --help         print this help, then exit
+  -t, --time-stamp   print date of last modification, then exit
+  -v, --version      print version number, then exit
+
+Report bugs and patches to <config-patches@gnu.org>."
+
+version="\
+GNU config.sub ($timestamp)
+
+Copyright 1992-2018 Free Software Foundation, Inc.
+
+This is free software; see the source for copying conditions.  There is NO
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
+
+help="
+Try \`$me --help' for more information."
+
+# Parse command line
+while test $# -gt 0 ; do
+  case $1 in
+    --time-stamp | --time* | -t )
+       echo "$timestamp" ; exit ;;
+    --version | -v )
+       echo "$version" ; exit ;;
+    --help | --h* | -h )
+       echo "$usage"; exit ;;
+    -- )     # Stop option processing
+       shift; break ;;
+    - )	# Use stdin as input.
+       break ;;
+    -* )
+       echo "$me: invalid option $1$help"
+       exit 1 ;;
+
+    *local*)
+       # First pass through any local machine types.
+       echo "$1"
+       exit ;;
+
+    * )
+       break ;;
+  esac
+done
+
+case $# in
+ 0) echo "$me: missing argument$help" >&2
+    exit 1;;
+ 1) ;;
+ *) echo "$me: too many arguments$help" >&2
+    exit 1;;
+esac
+
+# Separate what the user gave into CPU-COMPANY and OS or KERNEL-OS (if any).
+# Here we must recognize all the valid KERNEL-OS combinations.
+maybe_os=`echo "$1" | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\2/'`
+case $maybe_os in
+  nto-qnx* | linux-gnu* | linux-android* | linux-dietlibc | linux-newlib* | \
+  linux-musl* | linux-uclibc* | uclinux-uclibc* | uclinux-gnu* | kfreebsd*-gnu* | \
+  knetbsd*-gnu* | netbsd*-gnu* | netbsd*-eabi* | \
+  kopensolaris*-gnu* | cloudabi*-eabi* | \
+  storm-chaos* | os2-emx* | rtmk-nova*)
+    os=-$maybe_os
+    basic_machine=`echo "$1" | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\1/'`
+    ;;
+  android-linux)
+    os=-linux-android
+    basic_machine=`echo "$1" | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\1/'`-unknown
+    ;;
+  *)
+    basic_machine=`echo "$1" | sed 's/-[^-]*$//'`
+    if [ "$basic_machine" != "$1" ]
+    then os=`echo "$1" | sed 's/.*-/-/'`
+    else os=; fi
+    ;;
+esac
+
+### Let's recognize common machines as not being operating systems so
+### that things like config.sub decstation-3100 work.  We also
+### recognize some manufacturers as not being operating systems, so we
+### can provide default operating systems below.
+case $os in
+	-sun*os*)
+		# Prevent following clause from handling this invalid input.
+		;;
+	-dec* | -mips* | -sequent* | -encore* | -pc532* | -sgi* | -sony* | \
+	-att* | -7300* | -3300* | -delta* | -motorola* | -sun[234]* | \
+	-unicom* | -ibm* | -next | -hp | -isi* | -apollo | -altos* | \
+	-convergent* | -ncr* | -news | -32* | -3600* | -3100* | -hitachi* |\
+	-c[123]* | -convex* | -sun | -crds | -omron* | -dg | -ultra | -tti* | \
+	-harris | -dolphin | -highlevel | -gould | -cbm | -ns | -masscomp | \
+	-apple | -axis | -knuth | -cray | -microblaze*)
+		os=
+		basic_machine=$1
+		;;
+	-bluegene*)
+		os=-cnk
+		;;
+	-sim | -cisco | -oki | -wec | -winbond)
+		os=
+		basic_machine=$1
+		;;
+	-scout)
+		;;
+	-wrs)
+		os=-vxworks
+		basic_machine=$1
+		;;
+	-chorusos*)
+		os=-chorusos
+		basic_machine=$1
+		;;
+	-chorusrdb)
+		os=-chorusrdb
+		basic_machine=$1
+		;;
+	-hiux*)
+		os=-hiuxwe2
+		;;
+	-sco6)
+		os=-sco5v6
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-sco5)
+		os=-sco3.2v5
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-sco4)
+		os=-sco3.2v4
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-sco3.2.[4-9]*)
+		os=`echo $os | sed -e 's/sco3.2./sco3.2v/'`
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-sco3.2v[4-9]*)
+		# Don't forget version if it is 3.2v4 or newer.
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-sco5v6*)
+		# Don't forget version if it is 3.2v4 or newer.
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-sco*)
+		os=-sco3.2v2
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-udk*)
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-isc)
+		os=-isc2.2
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-clix*)
+		basic_machine=clipper-intergraph
+		;;
+	-isc*)
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-pc/'`
+		;;
+	-lynx*178)
+		os=-lynxos178
+		;;
+	-lynx*5)
+		os=-lynxos5
+		;;
+	-lynx*)
+		os=-lynxos
+		;;
+	-ptx*)
+		basic_machine=`echo "$1" | sed -e 's/86-.*/86-sequent/'`
+		;;
+	-psos*)
+		os=-psos
+		;;
+	-mint | -mint[0-9]*)
+		basic_machine=m68k-atari
+		os=-mint
+		;;
+esac
+
+# Decode aliases for certain CPU-COMPANY combinations.
+case $basic_machine in
+	# Recognize the basic CPU types without company name.
+	# Some are omitted here because they have special meanings below.
+	1750a | 580 \
+	| a29k \
+	| aarch64 | aarch64_be \
+	| alpha | alphaev[4-8] | alphaev56 | alphaev6[78] | alphapca5[67] \
+	| alpha64 | alpha64ev[4-8] | alpha64ev56 | alpha64ev6[78] | alpha64pca5[67] \
+	| am33_2.0 \
+	| arc | arceb \
+	| arm | arm[bl]e | arme[lb] | armv[2-8] | armv[3-8][lb] | armv7[arm] \
+	| avr | avr32 \
+	| ba \
+	| be32 | be64 \
+	| bfin \
+	| c4x | c8051 | clipper \
+	| d10v | d30v | dlx | dsp16xx \
+	| e2k | epiphany \
+	| fido | fr30 | frv | ft32 \
+	| h8300 | h8500 | hppa | hppa1.[01] | hppa2.0 | hppa2.0[nw] | hppa64 \
+	| hexagon \
+	| i370 | i860 | i960 | ia16 | ia64 \
+	| ip2k | iq2000 \
+	| k1om \
+	| le32 | le64 \
+	| lm32 \
+	| m32c | m32r | m32rle | m68000 | m68k | m88k \
+	| maxq | mb | microblaze | microblazeel | mcore | mep | metag \
+	| mips | mipsbe | mipseb | mipsel | mipsle \
+	| mips16 \
+	| mips64 | mips64el \
+	| mips64octeon | mips64octeonel \
+	| mips64orion | mips64orionel \
+	| mips64r5900 | mips64r5900el \
+	| mips64vr | mips64vrel \
+	| mips64vr4100 | mips64vr4100el \
+	| mips64vr4300 | mips64vr4300el \
+	| mips64vr5000 | mips64vr5000el \
+	| mips64vr5900 | mips64vr5900el \
+	| mipsisa32 | mipsisa32el \
+	| mipsisa32r2 | mipsisa32r2el \
+	| mipsisa32r6 | mipsisa32r6el \
+	| mipsisa64 | mipsisa64el \
+	| mipsisa64r2 | mipsisa64r2el \
+	| mipsisa64r6 | mipsisa64r6el \
+	| mipsisa64sb1 | mipsisa64sb1el \
+	| mipsisa64sr71k | mipsisa64sr71kel \
+	| mipsr5900 | mipsr5900el \
+	| mipstx39 | mipstx39el \
+	| mn10200 | mn10300 \
+	| moxie \
+	| mt \
+	| msp430 \
+	| nds32 | nds32le | nds32be \
+	| nios | nios2 | nios2eb | nios2el \
+	| ns16k | ns32k \
+	| open8 | or1k | or1knd | or32 \
+	| pdp10 | pj | pjl \
+	| powerpc | powerpc64 | powerpc64le | powerpcle \
+	| pru \
+	| pyramid \
+	| riscv32 | riscv64 \
+	| rl78 | rx \
+	| score \
+	| sh | sh[1234] | sh[24]a | sh[24]aeb | sh[23]e | sh[234]eb | sheb | shbe | shle | sh[1234]le | sh3ele \
+	| sh64 | sh64le \
+	| sparc | sparc64 | sparc64b | sparc64v | sparc86x | sparclet | sparclite \
+	| sparcv8 | sparcv9 | sparcv9b | sparcv9v \
+	| spu \
+	| tahoe | tic4x | tic54x | tic55x | tic6x | tic80 | tron \
+	| ubicom32 \
+	| v850 | v850e | v850e1 | v850e2 | v850es | v850e2v3 \
+	| visium \
+	| wasm32 \
+	| x86 | xc16x | xstormy16 | xtensa \
+	| z8k | z80)
+		basic_machine=$basic_machine-unknown
+		;;
+	c54x)
+		basic_machine=tic54x-unknown
+		;;
+	c55x)
+		basic_machine=tic55x-unknown
+		;;
+	c6x)
+		basic_machine=tic6x-unknown
+		;;
+	leon|leon[3-9])
+		basic_machine=sparc-$basic_machine
+		;;
+	m6811 | m68hc11 | m6812 | m68hc12 | m68hcs12x | nvptx | picochip)
+		basic_machine=$basic_machine-unknown
+		os=-none
+		;;
+	m88110 | m680[12346]0 | m683?2 | m68360 | m5200 | v70 | w65)
+		;;
+	ms1)
+		basic_machine=mt-unknown
+		;;
+
+	strongarm | thumb | xscale)
+		basic_machine=arm-unknown
+		;;
+	xgate)
+		basic_machine=$basic_machine-unknown
+		os=-none
+		;;
+	xscaleeb)
+		basic_machine=armeb-unknown
+		;;
+
+	xscaleel)
+		basic_machine=armel-unknown
+		;;
+
+	# We use `pc' rather than `unknown'
+	# because (1) that's what they normally are, and
+	# (2) the word "unknown" tends to confuse beginning users.
+	i*86 | x86_64)
+	  basic_machine=$basic_machine-pc
+	  ;;
+	# Object if more than one company name word.
+	*-*-*)
+		echo Invalid configuration \`"$1"\': machine \`"$basic_machine"\' not recognized 1>&2
+		exit 1
+		;;
+	# Recognize the basic CPU types with company name.
+	580-* \
+	| a29k-* \
+	| aarch64-* | aarch64_be-* \
+	| alpha-* | alphaev[4-8]-* | alphaev56-* | alphaev6[78]-* \
+	| alpha64-* | alpha64ev[4-8]-* | alpha64ev56-* | alpha64ev6[78]-* \
+	| alphapca5[67]-* | alpha64pca5[67]-* | arc-* | arceb-* \
+	| arm-*  | armbe-* | armle-* | armeb-* | armv*-* \
+	| avr-* | avr32-* \
+	| ba-* \
+	| be32-* | be64-* \
+	| bfin-* | bs2000-* \
+	| c[123]* | c30-* | [cjt]90-* | c4x-* \
+	| c8051-* | clipper-* | craynv-* | cydra-* \
+	| d10v-* | d30v-* | dlx-* \
+	| e2k-* | elxsi-* \
+	| f30[01]-* | f700-* | fido-* | fr30-* | frv-* | fx80-* \
+	| h8300-* | h8500-* \
+	| hppa-* | hppa1.[01]-* | hppa2.0-* | hppa2.0[nw]-* | hppa64-* \
+	| hexagon-* \
+	| i*86-* | i860-* | i960-* | ia16-* | ia64-* \
+	| ip2k-* | iq2000-* \
+	| k1om-* \
+	| le32-* | le64-* \
+	| lm32-* \
+	| m32c-* | m32r-* | m32rle-* \
+	| m68000-* | m680[012346]0-* | m68360-* | m683?2-* | m68k-* \
+	| m88110-* | m88k-* | maxq-* | mcore-* | metag-* \
+	| microblaze-* | microblazeel-* \
+	| mips-* | mipsbe-* | mipseb-* | mipsel-* | mipsle-* \
+	| mips16-* \
+	| mips64-* | mips64el-* \
+	| mips64octeon-* | mips64octeonel-* \
+	| mips64orion-* | mips64orionel-* \
+	| mips64r5900-* | mips64r5900el-* \
+	| mips64vr-* | mips64vrel-* \
+	| mips64vr4100-* | mips64vr4100el-* \
+	| mips64vr4300-* | mips64vr4300el-* \
+	| mips64vr5000-* | mips64vr5000el-* \
+	| mips64vr5900-* | mips64vr5900el-* \
+	| mipsisa32-* | mipsisa32el-* \
+	| mipsisa32r2-* | mipsisa32r2el-* \
+	| mipsisa32r6-* | mipsisa32r6el-* \
+	| mipsisa64-* | mipsisa64el-* \
+	| mipsisa64r2-* | mipsisa64r2el-* \
+	| mipsisa64r6-* | mipsisa64r6el-* \
+	| mipsisa64sb1-* | mipsisa64sb1el-* \
+	| mipsisa64sr71k-* | mipsisa64sr71kel-* \
+	| mipsr5900-* | mipsr5900el-* \
+	| mipstx39-* | mipstx39el-* \
+	| mmix-* \
+	| mt-* \
+	| msp430-* \
+	| nds32-* | nds32le-* | nds32be-* \
+	| nios-* | nios2-* | nios2eb-* | nios2el-* \
+	| none-* | np1-* | ns16k-* | ns32k-* \
+	| open8-* \
+	| or1k*-* \
+	| orion-* \
+	| pdp10-* | pdp11-* | pj-* | pjl-* | pn-* | power-* \
+	| powerpc-* | powerpc64-* | powerpc64le-* | powerpcle-* \
+	| pru-* \
+	| pyramid-* \
+	| riscv32-* | riscv64-* \
+	| rl78-* | romp-* | rs6000-* | rx-* \
+	| sh-* | sh[1234]-* | sh[24]a-* | sh[24]aeb-* | sh[23]e-* | sh[34]eb-* | sheb-* | shbe-* \
+	| shle-* | sh[1234]le-* | sh3ele-* | sh64-* | sh64le-* \
+	| sparc-* | sparc64-* | sparc64b-* | sparc64v-* | sparc86x-* | sparclet-* \
+	| sparclite-* \
+	| sparcv8-* | sparcv9-* | sparcv9b-* | sparcv9v-* | sv1-* | sx*-* \
+	| tahoe-* \
+	| tic30-* | tic4x-* | tic54x-* | tic55x-* | tic6x-* | tic80-* \
+	| tile*-* \
+	| tron-* \
+	| ubicom32-* \
+	| v850-* | v850e-* | v850e1-* | v850es-* | v850e2-* | v850e2v3-* \
+	| vax-* \
+	| visium-* \
+	| wasm32-* \
+	| we32k-* \
+	| x86-* | x86_64-* | xc16x-* | xps100-* \
+	| xstormy16-* | xtensa*-* \
+	| ymp-* \
+	| z8k-* | z80-*)
+		;;
+	# Recognize the basic CPU types without company name, with glob match.
+	xtensa*)
+		basic_machine=$basic_machine-unknown
+		;;
+	# Recognize the various machine names and aliases which stand
+	# for a CPU type and a company and sometimes even an OS.
+	386bsd)
+		basic_machine=i386-pc
+		os=-bsd
+		;;
+	3b1 | 7300 | 7300-att | att-7300 | pc7300 | safari | unixpc)
+		basic_machine=m68000-att
+		;;
+	3b*)
+		basic_machine=we32k-att
+		;;
+	a29khif)
+		basic_machine=a29k-amd
+		os=-udi
+		;;
+	abacus)
+		basic_machine=abacus-unknown
+		;;
+	adobe68k)
+		basic_machine=m68010-adobe
+		os=-scout
+		;;
+	alliant | fx80)
+		basic_machine=fx80-alliant
+		;;
+	altos | altos3068)
+		basic_machine=m68k-altos
+		;;
+	am29k)
+		basic_machine=a29k-none
+		os=-bsd
+		;;
+	amd64)
+		basic_machine=x86_64-pc
+		;;
+	amd64-*)
+		basic_machine=x86_64-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	amdahl)
+		basic_machine=580-amdahl
+		os=-sysv
+		;;
+	amiga | amiga-*)
+		basic_machine=m68k-unknown
+		;;
+	amigaos | amigados)
+		basic_machine=m68k-unknown
+		os=-amigaos
+		;;
+	amigaunix | amix)
+		basic_machine=m68k-unknown
+		os=-sysv4
+		;;
+	apollo68)
+		basic_machine=m68k-apollo
+		os=-sysv
+		;;
+	apollo68bsd)
+		basic_machine=m68k-apollo
+		os=-bsd
+		;;
+	aros)
+		basic_machine=i386-pc
+		os=-aros
+		;;
+	asmjs)
+		basic_machine=asmjs-unknown
+		;;
+	aux)
+		basic_machine=m68k-apple
+		os=-aux
+		;;
+	balance)
+		basic_machine=ns32k-sequent
+		os=-dynix
+		;;
+	blackfin)
+		basic_machine=bfin-unknown
+		os=-linux
+		;;
+	blackfin-*)
+		basic_machine=bfin-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		os=-linux
+		;;
+	bluegene*)
+		basic_machine=powerpc-ibm
+		os=-cnk
+		;;
+	c54x-*)
+		basic_machine=tic54x-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	c55x-*)
+		basic_machine=tic55x-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	c6x-*)
+		basic_machine=tic6x-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	c90)
+		basic_machine=c90-cray
+		os=-unicos
+		;;
+	cegcc)
+		basic_machine=arm-unknown
+		os=-cegcc
+		;;
+	convex-c1)
+		basic_machine=c1-convex
+		os=-bsd
+		;;
+	convex-c2)
+		basic_machine=c2-convex
+		os=-bsd
+		;;
+	convex-c32)
+		basic_machine=c32-convex
+		os=-bsd
+		;;
+	convex-c34)
+		basic_machine=c34-convex
+		os=-bsd
+		;;
+	convex-c38)
+		basic_machine=c38-convex
+		os=-bsd
+		;;
+	cray | j90)
+		basic_machine=j90-cray
+		os=-unicos
+		;;
+	craynv)
+		basic_machine=craynv-cray
+		os=-unicosmp
+		;;
+	cr16 | cr16-*)
+		basic_machine=cr16-unknown
+		os=-elf
+		;;
+	crds | unos)
+		basic_machine=m68k-crds
+		;;
+	crisv32 | crisv32-* | etraxfs*)
+		basic_machine=crisv32-axis
+		;;
+	cris | cris-* | etrax*)
+		basic_machine=cris-axis
+		;;
+	crx)
+		basic_machine=crx-unknown
+		os=-elf
+		;;
+	da30 | da30-*)
+		basic_machine=m68k-da30
+		;;
+	decstation | decstation-3100 | pmax | pmax-* | pmin | dec3100 | decstatn)
+		basic_machine=mips-dec
+		;;
+	decsystem10* | dec10*)
+		basic_machine=pdp10-dec
+		os=-tops10
+		;;
+	decsystem20* | dec20*)
+		basic_machine=pdp10-dec
+		os=-tops20
+		;;
+	delta | 3300 | motorola-3300 | motorola-delta \
+	      | 3300-motorola | delta-motorola)
+		basic_machine=m68k-motorola
+		;;
+	delta88)
+		basic_machine=m88k-motorola
+		os=-sysv3
+		;;
+	dicos)
+		basic_machine=i686-pc
+		os=-dicos
+		;;
+	djgpp)
+		basic_machine=i586-pc
+		os=-msdosdjgpp
+		;;
+	dpx20 | dpx20-*)
+		basic_machine=rs6000-bull
+		os=-bosx
+		;;
+	dpx2*)
+		basic_machine=m68k-bull
+		os=-sysv3
+		;;
+	e500v[12])
+		basic_machine=powerpc-unknown
+		os=$os"spe"
+		;;
+	e500v[12]-*)
+		basic_machine=powerpc-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		os=$os"spe"
+		;;
+	ebmon29k)
+		basic_machine=a29k-amd
+		os=-ebmon
+		;;
+	elxsi)
+		basic_machine=elxsi-elxsi
+		os=-bsd
+		;;
+	encore | umax | mmax)
+		basic_machine=ns32k-encore
+		;;
+	es1800 | OSE68k | ose68k | ose | OSE)
+		basic_machine=m68k-ericsson
+		os=-ose
+		;;
+	fx2800)
+		basic_machine=i860-alliant
+		;;
+	genix)
+		basic_machine=ns32k-ns
+		;;
+	gmicro)
+		basic_machine=tron-gmicro
+		os=-sysv
+		;;
+	go32)
+		basic_machine=i386-pc
+		os=-go32
+		;;
+	h3050r* | hiux*)
+		basic_machine=hppa1.1-hitachi
+		os=-hiuxwe2
+		;;
+	h8300hms)
+		basic_machine=h8300-hitachi
+		os=-hms
+		;;
+	h8300xray)
+		basic_machine=h8300-hitachi
+		os=-xray
+		;;
+	h8500hms)
+		basic_machine=h8500-hitachi
+		os=-hms
+		;;
+	harris)
+		basic_machine=m88k-harris
+		os=-sysv3
+		;;
+	hp300-*)
+		basic_machine=m68k-hp
+		;;
+	hp300bsd)
+		basic_machine=m68k-hp
+		os=-bsd
+		;;
+	hp300hpux)
+		basic_machine=m68k-hp
+		os=-hpux
+		;;
+	hp3k9[0-9][0-9] | hp9[0-9][0-9])
+		basic_machine=hppa1.0-hp
+		;;
+	hp9k2[0-9][0-9] | hp9k31[0-9])
+		basic_machine=m68000-hp
+		;;
+	hp9k3[2-9][0-9])
+		basic_machine=m68k-hp
+		;;
+	hp9k6[0-9][0-9] | hp6[0-9][0-9])
+		basic_machine=hppa1.0-hp
+		;;
+	hp9k7[0-79][0-9] | hp7[0-79][0-9])
+		basic_machine=hppa1.1-hp
+		;;
+	hp9k78[0-9] | hp78[0-9])
+		# FIXME: really hppa2.0-hp
+		basic_machine=hppa1.1-hp
+		;;
+	hp9k8[67]1 | hp8[67]1 | hp9k80[24] | hp80[24] | hp9k8[78]9 | hp8[78]9 | hp9k893 | hp893)
+		# FIXME: really hppa2.0-hp
+		basic_machine=hppa1.1-hp
+		;;
+	hp9k8[0-9][13679] | hp8[0-9][13679])
+		basic_machine=hppa1.1-hp
+		;;
+	hp9k8[0-9][0-9] | hp8[0-9][0-9])
+		basic_machine=hppa1.0-hp
+		;;
+	hppaosf)
+		basic_machine=hppa1.1-hp
+		os=-osf
+		;;
+	hppro)
+		basic_machine=hppa1.1-hp
+		os=-proelf
+		;;
+	i370-ibm* | ibm*)
+		basic_machine=i370-ibm
+		;;
+	i*86v32)
+		basic_machine=`echo "$1" | sed -e 's/86.*/86-pc/'`
+		os=-sysv32
+		;;
+	i*86v4*)
+		basic_machine=`echo "$1" | sed -e 's/86.*/86-pc/'`
+		os=-sysv4
+		;;
+	i*86v)
+		basic_machine=`echo "$1" | sed -e 's/86.*/86-pc/'`
+		os=-sysv
+		;;
+	i*86sol2)
+		basic_machine=`echo "$1" | sed -e 's/86.*/86-pc/'`
+		os=-solaris2
+		;;
+	i386mach)
+		basic_machine=i386-mach
+		os=-mach
+		;;
+	vsta)
+		basic_machine=i386-unknown
+		os=-vsta
+		;;
+	iris | iris4d)
+		basic_machine=mips-sgi
+		case $os in
+		    -irix*)
+			;;
+		    *)
+			os=-irix4
+			;;
+		esac
+		;;
+	isi68 | isi)
+		basic_machine=m68k-isi
+		os=-sysv
+		;;
+	leon-*|leon[3-9]-*)
+		basic_machine=sparc-`echo "$basic_machine" | sed 's/-.*//'`
+		;;
+	m68knommu)
+		basic_machine=m68k-unknown
+		os=-linux
+		;;
+	m68knommu-*)
+		basic_machine=m68k-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		os=-linux
+		;;
+	magnum | m3230)
+		basic_machine=mips-mips
+		os=-sysv
+		;;
+	merlin)
+		basic_machine=ns32k-utek
+		os=-sysv
+		;;
+	microblaze*)
+		basic_machine=microblaze-xilinx
+		;;
+	mingw64)
+		basic_machine=x86_64-pc
+		os=-mingw64
+		;;
+	mingw32)
+		basic_machine=i686-pc
+		os=-mingw32
+		;;
+	mingw32ce)
+		basic_machine=arm-unknown
+		os=-mingw32ce
+		;;
+	miniframe)
+		basic_machine=m68000-convergent
+		;;
+	*mint | -mint[0-9]* | *MiNT | *MiNT[0-9]*)
+		basic_machine=m68k-atari
+		os=-mint
+		;;
+	mips3*-*)
+		basic_machine=`echo "$basic_machine" | sed -e 's/mips3/mips64/'`
+		;;
+	mips3*)
+		basic_machine=`echo "$basic_machine" | sed -e 's/mips3/mips64/'`-unknown
+		;;
+	monitor)
+		basic_machine=m68k-rom68k
+		os=-coff
+		;;
+	morphos)
+		basic_machine=powerpc-unknown
+		os=-morphos
+		;;
+	moxiebox)
+		basic_machine=moxie-unknown
+		os=-moxiebox
+		;;
+	msdos)
+		basic_machine=i386-pc
+		os=-msdos
+		;;
+	ms1-*)
+		basic_machine=`echo "$basic_machine" | sed -e 's/ms1-/mt-/'`
+		;;
+	msys)
+		basic_machine=i686-pc
+		os=-msys
+		;;
+	mvs)
+		basic_machine=i370-ibm
+		os=-mvs
+		;;
+	nacl)
+		basic_machine=le32-unknown
+		os=-nacl
+		;;
+	ncr3000)
+		basic_machine=i486-ncr
+		os=-sysv4
+		;;
+	netbsd386)
+		basic_machine=i386-unknown
+		os=-netbsd
+		;;
+	netwinder)
+		basic_machine=armv4l-rebel
+		os=-linux
+		;;
+	news | news700 | news800 | news900)
+		basic_machine=m68k-sony
+		os=-newsos
+		;;
+	news1000)
+		basic_machine=m68030-sony
+		os=-newsos
+		;;
+	news-3600 | risc-news)
+		basic_machine=mips-sony
+		os=-newsos
+		;;
+	necv70)
+		basic_machine=v70-nec
+		os=-sysv
+		;;
+	next | m*-next)
+		basic_machine=m68k-next
+		case $os in
+		    -nextstep* )
+			;;
+		    -ns2*)
+		      os=-nextstep2
+			;;
+		    *)
+		      os=-nextstep3
+			;;
+		esac
+		;;
+	nh3000)
+		basic_machine=m68k-harris
+		os=-cxux
+		;;
+	nh[45]000)
+		basic_machine=m88k-harris
+		os=-cxux
+		;;
+	nindy960)
+		basic_machine=i960-intel
+		os=-nindy
+		;;
+	mon960)
+		basic_machine=i960-intel
+		os=-mon960
+		;;
+	nonstopux)
+		basic_machine=mips-compaq
+		os=-nonstopux
+		;;
+	np1)
+		basic_machine=np1-gould
+		;;
+	neo-tandem)
+		basic_machine=neo-tandem
+		;;
+	nse-tandem)
+		basic_machine=nse-tandem
+		;;
+	nsr-tandem)
+		basic_machine=nsr-tandem
+		;;
+	nsv-tandem)
+		basic_machine=nsv-tandem
+		;;
+	nsx-tandem)
+		basic_machine=nsx-tandem
+		;;
+	op50n-* | op60c-*)
+		basic_machine=hppa1.1-oki
+		os=-proelf
+		;;
+	openrisc | openrisc-*)
+		basic_machine=or32-unknown
+		;;
+	os400)
+		basic_machine=powerpc-ibm
+		os=-os400
+		;;
+	OSE68000 | ose68000)
+		basic_machine=m68000-ericsson
+		os=-ose
+		;;
+	os68k)
+		basic_machine=m68k-none
+		os=-os68k
+		;;
+	pa-hitachi)
+		basic_machine=hppa1.1-hitachi
+		os=-hiuxwe2
+		;;
+	paragon)
+		basic_machine=i860-intel
+		os=-osf
+		;;
+	parisc)
+		basic_machine=hppa-unknown
+		os=-linux
+		;;
+	parisc-*)
+		basic_machine=hppa-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		os=-linux
+		;;
+	pbd)
+		basic_machine=sparc-tti
+		;;
+	pbb)
+		basic_machine=m68k-tti
+		;;
+	pc532 | pc532-*)
+		basic_machine=ns32k-pc532
+		;;
+	pc98)
+		basic_machine=i386-pc
+		;;
+	pc98-*)
+		basic_machine=i386-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	pentium | p5 | k5 | k6 | nexgen | viac3)
+		basic_machine=i586-pc
+		;;
+	pentiumpro | p6 | 6x86 | athlon | athlon_*)
+		basic_machine=i686-pc
+		;;
+	pentiumii | pentium2 | pentiumiii | pentium3)
+		basic_machine=i686-pc
+		;;
+	pentium4)
+		basic_machine=i786-pc
+		;;
+	pentium-* | p5-* | k5-* | k6-* | nexgen-* | viac3-*)
+		basic_machine=i586-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	pentiumpro-* | p6-* | 6x86-* | athlon-*)
+		basic_machine=i686-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	pentiumii-* | pentium2-* | pentiumiii-* | pentium3-*)
+		basic_machine=i686-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	pentium4-*)
+		basic_machine=i786-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	pn)
+		basic_machine=pn-gould
+		;;
+	power)	basic_machine=power-ibm
+		;;
+	ppc | ppcbe)	basic_machine=powerpc-unknown
+		;;
+	ppc-* | ppcbe-*)
+		basic_machine=powerpc-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	ppcle | powerpclittle)
+		basic_machine=powerpcle-unknown
+		;;
+	ppcle-* | powerpclittle-*)
+		basic_machine=powerpcle-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	ppc64)	basic_machine=powerpc64-unknown
+		;;
+	ppc64-*) basic_machine=powerpc64-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	ppc64le | powerpc64little)
+		basic_machine=powerpc64le-unknown
+		;;
+	ppc64le-* | powerpc64little-*)
+		basic_machine=powerpc64le-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	ps2)
+		basic_machine=i386-ibm
+		;;
+	pw32)
+		basic_machine=i586-unknown
+		os=-pw32
+		;;
+	rdos | rdos64)
+		basic_machine=x86_64-pc
+		os=-rdos
+		;;
+	rdos32)
+		basic_machine=i386-pc
+		os=-rdos
+		;;
+	rom68k)
+		basic_machine=m68k-rom68k
+		os=-coff
+		;;
+	rm[46]00)
+		basic_machine=mips-siemens
+		;;
+	rtpc | rtpc-*)
+		basic_machine=romp-ibm
+		;;
+	s390 | s390-*)
+		basic_machine=s390-ibm
+		;;
+	s390x | s390x-*)
+		basic_machine=s390x-ibm
+		;;
+	sa29200)
+		basic_machine=a29k-amd
+		os=-udi
+		;;
+	sb1)
+		basic_machine=mipsisa64sb1-unknown
+		;;
+	sb1el)
+		basic_machine=mipsisa64sb1el-unknown
+		;;
+	sde)
+		basic_machine=mipsisa32-sde
+		os=-elf
+		;;
+	sei)
+		basic_machine=mips-sei
+		os=-seiux
+		;;
+	sequent)
+		basic_machine=i386-sequent
+		;;
+	sh5el)
+		basic_machine=sh5le-unknown
+		;;
+	simso-wrs)
+		basic_machine=sparclite-wrs
+		os=-vxworks
+		;;
+	sps7)
+		basic_machine=m68k-bull
+		os=-sysv2
+		;;
+	spur)
+		basic_machine=spur-unknown
+		;;
+	st2000)
+		basic_machine=m68k-tandem
+		;;
+	stratus)
+		basic_machine=i860-stratus
+		os=-sysv4
+		;;
+	strongarm-* | thumb-*)
+		basic_machine=arm-`echo "$basic_machine" | sed 's/^[^-]*-//'`
+		;;
+	sun2)
+		basic_machine=m68000-sun
+		;;
+	sun2os3)
+		basic_machine=m68000-sun
+		os=-sunos3
+		;;
+	sun2os4)
+		basic_machine=m68000-sun
+		os=-sunos4
+		;;
+	sun3os3)
+		basic_machine=m68k-sun
+		os=-sunos3
+		;;
+	sun3os4)
+		basic_machine=m68k-sun
+		os=-sunos4
+		;;
+	sun4os3)
+		basic_machine=sparc-sun
+		os=-sunos3
+		;;
+	sun4os4)
+		basic_machine=sparc-sun
+		os=-sunos4
+		;;
+	sun4sol2)
+		basic_machine=sparc-sun
+		os=-solaris2
+		;;
+	sun3 | sun3-*)
+		basic_machine=m68k-sun
+		;;
+	sun4)
+		basic_machine=sparc-sun
+		;;
+	sun386 | sun386i | roadrunner)
+		basic_machine=i386-sun
+		;;
+	sv1)
+		basic_machine=sv1-cray
+		os=-unicos
+		;;
+	symmetry)
+		basic_machine=i386-sequent
+		os=-dynix
+		;;
+	t3e)
+		basic_machine=alphaev5-cray
+		os=-unicos
+		;;
+	t90)
+		basic_machine=t90-cray
+		os=-unicos
+		;;
+	tile*)
+		basic_machine=$basic_machine-unknown
+		os=-linux-gnu
+		;;
+	tx39)
+		basic_machine=mipstx39-unknown
+		;;
+	tx39el)
+		basic_machine=mipstx39el-unknown
+		;;
+	toad1)
+		basic_machine=pdp10-xkl
+		os=-tops20
+		;;
+	tower | tower-32)
+		basic_machine=m68k-ncr
+		;;
+	tpf)
+		basic_machine=s390x-ibm
+		os=-tpf
+		;;
+	udi29k)
+		basic_machine=a29k-amd
+		os=-udi
+		;;
+	ultra3)
+		basic_machine=a29k-nyu
+		os=-sym1
+		;;
+	v810 | necv810)
+		basic_machine=v810-nec
+		os=-none
+		;;
+	vaxv)
+		basic_machine=vax-dec
+		os=-sysv
+		;;
+	vms)
+		basic_machine=vax-dec
+		os=-vms
+		;;
+	vpp*|vx|vx-*)
+		basic_machine=f301-fujitsu
+		;;
+	vxworks960)
+		basic_machine=i960-wrs
+		os=-vxworks
+		;;
+	vxworks68)
+		basic_machine=m68k-wrs
+		os=-vxworks
+		;;
+	vxworks29k)
+		basic_machine=a29k-wrs
+		os=-vxworks
+		;;
+	w65*)
+		basic_machine=w65-wdc
+		os=-none
+		;;
+	w89k-*)
+		basic_machine=hppa1.1-winbond
+		os=-proelf
+		;;
+	x64)
+		basic_machine=x86_64-pc
+		;;
+	xbox)
+		basic_machine=i686-pc
+		os=-mingw32
+		;;
+	xps | xps100)
+		basic_machine=xps100-honeywell
+		;;
+	xscale-* | xscalee[bl]-*)
+		basic_machine=`echo "$basic_machine" | sed 's/^xscale/arm/'`
+		;;
+	ymp)
+		basic_machine=ymp-cray
+		os=-unicos
+		;;
+	none)
+		basic_machine=none-none
+		os=-none
+		;;
+
+# Here we handle the default manufacturer of certain CPU types.  It is in
+# some cases the only manufacturer, in others, it is the most popular.
+	w89k)
+		basic_machine=hppa1.1-winbond
+		;;
+	op50n)
+		basic_machine=hppa1.1-oki
+		;;
+	op60c)
+		basic_machine=hppa1.1-oki
+		;;
+	romp)
+		basic_machine=romp-ibm
+		;;
+	mmix)
+		basic_machine=mmix-knuth
+		;;
+	rs6000)
+		basic_machine=rs6000-ibm
+		;;
+	vax)
+		basic_machine=vax-dec
+		;;
+	pdp11)
+		basic_machine=pdp11-dec
+		;;
+	we32k)
+		basic_machine=we32k-att
+		;;
+	sh[1234] | sh[24]a | sh[24]aeb | sh[34]eb | sh[1234]le | sh[23]ele)
+		basic_machine=sh-unknown
+		;;
+	cydra)
+		basic_machine=cydra-cydrome
+		;;
+	orion)
+		basic_machine=orion-highlevel
+		;;
+	orion105)
+		basic_machine=clipper-highlevel
+		;;
+	mac | mpw | mac-mpw)
+		basic_machine=m68k-apple
+		;;
+	pmac | pmac-mpw)
+		basic_machine=powerpc-apple
+		;;
+	*-unknown)
+		# Make sure to match an already-canonicalized machine name.
+		;;
+	*)
+		echo Invalid configuration \`"$1"\': machine \`"$basic_machine"\' not recognized 1>&2
+		exit 1
+		;;
+esac
+
+# Here we canonicalize certain aliases for manufacturers.
+case $basic_machine in
+	*-digital*)
+		basic_machine=`echo "$basic_machine" | sed 's/digital.*/dec/'`
+		;;
+	*-commodore*)
+		basic_machine=`echo "$basic_machine" | sed 's/commodore.*/cbm/'`
+		;;
+	*)
+		;;
+esac
+
+# Decode manufacturer-specific aliases for certain operating systems.
+
+if [ x"$os" != x"" ]
+then
+case $os in
+	# First match some system type aliases that might get confused
+	# with valid system types.
+	# -solaris* is a basic system type, with this one exception.
+	-auroraux)
+		os=-auroraux
+		;;
+	-solaris1 | -solaris1.*)
+		os=`echo $os | sed -e 's|solaris1|sunos4|'`
+		;;
+	-solaris)
+		os=-solaris2
+		;;
+	-unixware*)
+		os=-sysv4.2uw
+		;;
+	-gnu/linux*)
+		os=`echo $os | sed -e 's|gnu/linux|linux-gnu|'`
+		;;
+	# es1800 is here to avoid being matched by es* (a different OS)
+	-es1800*)
+		os=-ose
+		;;
+	# Now accept the basic system types.
+	# The portable systems comes first.
+	# Each alternative MUST end in a * to match a version number.
+	# -sysv* is not here because it comes later, after sysvr4.
+	-gnu* | -bsd* | -mach* | -minix* | -genix* | -ultrix* | -irix* \
+	      | -*vms* | -sco* | -esix* | -isc* | -aix* | -cnk* | -sunos | -sunos[34]*\
+	      | -hpux* | -unos* | -osf* | -luna* | -dgux* | -auroraux* | -solaris* \
+	      | -sym* | -kopensolaris* | -plan9* \
+	      | -amigaos* | -amigados* | -msdos* | -newsos* | -unicos* | -aof* \
+	      | -aos* | -aros* | -cloudabi* | -sortix* \
+	      | -nindy* | -vxsim* | -vxworks* | -ebmon* | -hms* | -mvs* \
+	      | -clix* | -riscos* | -uniplus* | -iris* | -rtu* | -xenix* \
+	      | -hiux* | -knetbsd* | -mirbsd* | -netbsd* \
+	      | -bitrig* | -openbsd* | -solidbsd* | -libertybsd* \
+	      | -ekkobsd* | -kfreebsd* | -freebsd* | -riscix* | -lynxos* \
+	      | -bosx* | -nextstep* | -cxux* | -aout* | -elf* | -oabi* \
+	      | -ptx* | -coff* | -ecoff* | -winnt* | -domain* | -vsta* \
+	      | -udi* | -eabi* | -lites* | -ieee* | -go32* | -aux* | -hcos* \
+	      | -chorusos* | -chorusrdb* | -cegcc* | -glidix* \
+	      | -cygwin* | -msys* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
+	      | -midipix* | -mingw32* | -mingw64* | -linux-gnu* | -linux-android* \
+	      | -linux-newlib* | -linux-musl* | -linux-uclibc* \
+	      | -uxpv* | -beos* | -mpeix* | -udk* | -moxiebox* \
+	      | -interix* | -uwin* | -mks* | -rhapsody* | -darwin* \
+	      | -openstep* | -oskit* | -conix* | -pw32* | -nonstopux* \
+	      | -storm-chaos* | -tops10* | -tenex* | -tops20* | -its* \
+	      | -os2* | -vos* | -palmos* | -uclinux* | -nucleus* \
+	      | -morphos* | -superux* | -rtmk* | -windiss* \
+	      | -powermax* | -dnix* | -nx6 | -nx7 | -sei* | -dragonfly* \
+	      | -skyos* | -haiku* | -rdos* | -toppers* | -drops* | -es* \
+	      | -onefs* | -tirtos* | -phoenix* | -fuchsia* | -redox* | -bme* \
+	      | -midnightbsd*)
+	# Remember, each alternative MUST END IN *, to match a version number.
+		;;
+	-qnx*)
+		case $basic_machine in
+		    x86-* | i*86-*)
+			;;
+		    *)
+			os=-nto$os
+			;;
+		esac
+		;;
+	-nto-qnx*)
+		;;
+	-nto*)
+		os=`echo $os | sed -e 's|nto|nto-qnx|'`
+		;;
+	-sim | -xray | -os68k* | -v88r* \
+	      | -windows* | -osx | -abug | -netware* | -os9* \
+	      | -macos* | -mpw* | -magic* | -mmixware* | -mon960* | -lnews*)
+		;;
+	-mac*)
+		os=`echo "$os" | sed -e 's|mac|macos|'`
+		;;
+	-linux-dietlibc)
+		os=-linux-dietlibc
+		;;
+	-linux*)
+		os=`echo $os | sed -e 's|linux|linux-gnu|'`
+		;;
+	-sunos5*)
+		os=`echo "$os" | sed -e 's|sunos5|solaris2|'`
+		;;
+	-sunos6*)
+		os=`echo "$os" | sed -e 's|sunos6|solaris3|'`
+		;;
+	-opened*)
+		os=-openedition
+		;;
+	-os400*)
+		os=-os400
+		;;
+	-wince*)
+		os=-wince
+		;;
+	-utek*)
+		os=-bsd
+		;;
+	-dynix*)
+		os=-bsd
+		;;
+	-acis*)
+		os=-aos
+		;;
+	-atheos*)
+		os=-atheos
+		;;
+	-syllable*)
+		os=-syllable
+		;;
+	-386bsd)
+		os=-bsd
+		;;
+	-ctix* | -uts*)
+		os=-sysv
+		;;
+	-nova*)
+		os=-rtmk-nova
+		;;
+	-ns2)
+		os=-nextstep2
+		;;
+	-nsk*)
+		os=-nsk
+		;;
+	# Preserve the version number of sinix5.
+	-sinix5.*)
+		os=`echo $os | sed -e 's|sinix|sysv|'`
+		;;
+	-sinix*)
+		os=-sysv4
+		;;
+	-tpf*)
+		os=-tpf
+		;;
+	-triton*)
+		os=-sysv3
+		;;
+	-oss*)
+		os=-sysv3
+		;;
+	-svr4*)
+		os=-sysv4
+		;;
+	-svr3)
+		os=-sysv3
+		;;
+	-sysvr4)
+		os=-sysv4
+		;;
+	# This must come after -sysvr4.
+	-sysv*)
+		;;
+	-ose*)
+		os=-ose
+		;;
+	-*mint | -mint[0-9]* | -*MiNT | -MiNT[0-9]*)
+		os=-mint
+		;;
+	-zvmoe)
+		os=-zvmoe
+		;;
+	-dicos*)
+		os=-dicos
+		;;
+	-pikeos*)
+		# Until real need of OS specific support for
+		# particular features comes up, bare metal
+		# configurations are quite functional.
+		case $basic_machine in
+		    arm*)
+			os=-eabi
+			;;
+		    *)
+			os=-elf
+			;;
+		esac
+		;;
+	-nacl*)
+		;;
+	-ios)
+		;;
+	-none)
+		;;
+	*)
+		# Get rid of the `-' at the beginning of $os.
+		os=`echo $os | sed 's/[^-]*-//'`
+		echo Invalid configuration \`"$1"\': system \`"$os"\' not recognized 1>&2
+		exit 1
+		;;
+esac
+else
+
+# Here we handle the default operating systems that come with various machines.
+# The value should be what the vendor currently ships out the door with their
+# machine or put another way, the most popular os provided with the machine.
+
+# Note that if you're going to try to match "-MANUFACTURER" here (say,
+# "-sun"), then you have to tell the case statement up towards the top
+# that MANUFACTURER isn't an operating system.  Otherwise, code above
+# will signal an error saying that MANUFACTURER isn't an operating
+# system, and we'll never get to this point.
+
+case $basic_machine in
+	score-*)
+		os=-elf
+		;;
+	spu-*)
+		os=-elf
+		;;
+	*-acorn)
+		os=-riscix1.2
+		;;
+	arm*-rebel)
+		os=-linux
+		;;
+	arm*-semi)
+		os=-aout
+		;;
+	c4x-* | tic4x-*)
+		os=-coff
+		;;
+	c8051-*)
+		os=-elf
+		;;
+	hexagon-*)
+		os=-elf
+		;;
+	tic54x-*)
+		os=-coff
+		;;
+	tic55x-*)
+		os=-coff
+		;;
+	tic6x-*)
+		os=-coff
+		;;
+	# This must come before the *-dec entry.
+	pdp10-*)
+		os=-tops20
+		;;
+	pdp11-*)
+		os=-none
+		;;
+	*-dec | vax-*)
+		os=-ultrix4.2
+		;;
+	m68*-apollo)
+		os=-domain
+		;;
+	i386-sun)
+		os=-sunos4.0.2
+		;;
+	m68000-sun)
+		os=-sunos3
+		;;
+	m68*-cisco)
+		os=-aout
+		;;
+	mep-*)
+		os=-elf
+		;;
+	mips*-cisco)
+		os=-elf
+		;;
+	mips*-*)
+		os=-elf
+		;;
+	or32-*)
+		os=-coff
+		;;
+	*-tti)	# must be before sparc entry or we get the wrong os.
+		os=-sysv3
+		;;
+	sparc-* | *-sun)
+		os=-sunos4.1.1
+		;;
+	pru-*)
+		os=-elf
+		;;
+	*-be)
+		os=-beos
+		;;
+	*-ibm)
+		os=-aix
+		;;
+	*-knuth)
+		os=-mmixware
+		;;
+	*-wec)
+		os=-proelf
+		;;
+	*-winbond)
+		os=-proelf
+		;;
+	*-oki)
+		os=-proelf
+		;;
+	*-hp)
+		os=-hpux
+		;;
+	*-hitachi)
+		os=-hiux
+		;;
+	i860-* | *-att | *-ncr | *-altos | *-motorola | *-convergent)
+		os=-sysv
+		;;
+	*-cbm)
+		os=-amigaos
+		;;
+	*-dg)
+		os=-dgux
+		;;
+	*-dolphin)
+		os=-sysv3
+		;;
+	m68k-ccur)
+		os=-rtu
+		;;
+	m88k-omron*)
+		os=-luna
+		;;
+	*-next)
+		os=-nextstep
+		;;
+	*-sequent)
+		os=-ptx
+		;;
+	*-crds)
+		os=-unos
+		;;
+	*-ns)
+		os=-genix
+		;;
+	i370-*)
+		os=-mvs
+		;;
+	*-gould)
+		os=-sysv
+		;;
+	*-highlevel)
+		os=-bsd
+		;;
+	*-encore)
+		os=-bsd
+		;;
+	*-sgi)
+		os=-irix
+		;;
+	*-siemens)
+		os=-sysv4
+		;;
+	*-masscomp)
+		os=-rtu
+		;;
+	f30[01]-fujitsu | f700-fujitsu)
+		os=-uxpv
+		;;
+	*-rom68k)
+		os=-coff
+		;;
+	*-*bug)
+		os=-coff
+		;;
+	*-apple)
+		os=-macos
+		;;
+	*-atari*)
+		os=-mint
+		;;
+	*)
+		os=-none
+		;;
+esac
+fi
+
+# Here we handle the case where we know the os, and the CPU type, but not the
+# manufacturer.  We pick the logical manufacturer.
+vendor=unknown
+case $basic_machine in
+	*-unknown)
+		case $os in
+			-riscix*)
+				vendor=acorn
+				;;
+			-sunos*)
+				vendor=sun
+				;;
+			-cnk*|-aix*)
+				vendor=ibm
+				;;
+			-beos*)
+				vendor=be
+				;;
+			-hpux*)
+				vendor=hp
+				;;
+			-mpeix*)
+				vendor=hp
+				;;
+			-hiux*)
+				vendor=hitachi
+				;;
+			-unos*)
+				vendor=crds
+				;;
+			-dgux*)
+				vendor=dg
+				;;
+			-luna*)
+				vendor=omron
+				;;
+			-genix*)
+				vendor=ns
+				;;
+			-mvs* | -opened*)
+				vendor=ibm
+				;;
+			-os400*)
+				vendor=ibm
+				;;
+			-ptx*)
+				vendor=sequent
+				;;
+			-tpf*)
+				vendor=ibm
+				;;
+			-vxsim* | -vxworks* | -windiss*)
+				vendor=wrs
+				;;
+			-aux*)
+				vendor=apple
+				;;
+			-hms*)
+				vendor=hitachi
+				;;
+			-mpw* | -macos*)
+				vendor=apple
+				;;
+			-*mint | -mint[0-9]* | -*MiNT | -MiNT[0-9]*)
+				vendor=atari
+				;;
+			-vos*)
+				vendor=stratus
+				;;
+		esac
+		basic_machine=`echo "$basic_machine" | sed "s/unknown/$vendor/"`
+		;;
+esac
+
+echo "$basic_machine$os"
+exit
+
+# Local variables:
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "timestamp='"
+# time-stamp-format: "%:y-%02m-%02d"
+# time-stamp-end: "'"
+# End:
diff --git a/extern/libpng/configure b/extern/libpng/configure
new file mode 100755
index 0000000000..1b2c46366b
--- /dev/null
+++ b/extern/libpng/configure
@@ -0,0 +1,16116 @@
+#! /bin/sh
+# Guess values for system-dependent variables and create Makefiles.
+# Generated by GNU Autoconf 2.69 for libpng 1.6.37.
+#
+# Report bugs to <png-mng-implement@lists.sourceforge.net>.
+#
+#
+# Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc.
+#
+#
+# This configure script is free software; the Free Software Foundation
+# gives unlimited permission to copy, distribute and modify it.
+## -------------------- ##
+## M4sh Initialization. ##
+## -------------------- ##
+
+# Be more Bourne compatible
+DUALCASE=1; export DUALCASE # for MKS sh
+if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else
+  case `(set -o) 2>/dev/null` in #(
+  *posix*) :
+    set -o posix ;; #(
+  *) :
+     ;;
+esac
+fi
+
+
+as_nl='
+'
+export as_nl
+# Printing a long string crashes Solaris 7 /usr/bin/printf.
+as_echo='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
+as_echo=$as_echo$as_echo$as_echo$as_echo$as_echo
+as_echo=$as_echo$as_echo$as_echo$as_echo$as_echo$as_echo
+# Prefer a ksh shell builtin over an external printf program on Solaris,
+# but without wasting forks for bash or zsh.
+if test -z "$BASH_VERSION$ZSH_VERSION" \
+    && (test "X`print -r -- $as_echo`" = "X$as_echo") 2>/dev/null; then
+  as_echo='print -r --'
+  as_echo_n='print -rn --'
+elif (test "X`printf %s $as_echo`" = "X$as_echo") 2>/dev/null; then
+  as_echo='printf %s\n'
+  as_echo_n='printf %s'
+else
+  if test "X`(/usr/ucb/echo -n -n $as_echo) 2>/dev/null`" = "X-n $as_echo"; then
+    as_echo_body='eval /usr/ucb/echo -n "$1$as_nl"'
+    as_echo_n='/usr/ucb/echo -n'
+  else
+    as_echo_body='eval expr "X$1" : "X\\(.*\\)"'
+    as_echo_n_body='eval
+      arg=$1;
+      case $arg in #(
+      *"$as_nl"*)
+	expr "X$arg" : "X\\(.*\\)$as_nl";
+	arg=`expr "X$arg" : ".*$as_nl\\(.*\\)"`;;
+      esac;
+      expr "X$arg" : "X\\(.*\\)" | tr -d "$as_nl"
+    '
+    export as_echo_n_body
+    as_echo_n='sh -c $as_echo_n_body as_echo'
+  fi
+  export as_echo_body
+  as_echo='sh -c $as_echo_body as_echo'
+fi
+
+# The user is always right.
+if test "${PATH_SEPARATOR+set}" != set; then
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
+    (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
+      PATH_SEPARATOR=';'
+  }
+fi
+
+
+# IFS
+# We need space, tab and new line, in precisely that order.  Quoting is
+# there to prevent editors from complaining about space-tab.
+# (If _AS_PATH_WALK were called with IFS unset, it would disable word
+# splitting by setting IFS to empty value.)
+IFS=" ""	$as_nl"
+
+# Find who we are.  Look in the path if we contain no directory separator.
+as_myself=
+case $0 in #((
+  *[\\/]* ) as_myself=$0 ;;
+  *) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    test -r "$as_dir/$0" && as_myself=$as_dir/$0 && break
+  done
+IFS=$as_save_IFS
+
+     ;;
+esac
+# We did not find ourselves, most probably we were run as `sh COMMAND'
+# in which case we are not to be found in the path.
+if test "x$as_myself" = x; then
+  as_myself=$0
+fi
+if test ! -f "$as_myself"; then
+  $as_echo "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
+  exit 1
+fi
+
+# Unset variables that we do not need and which cause bugs (e.g. in
+# pre-3.0 UWIN ksh).  But do not cause bugs in bash 2.01; the "|| exit 1"
+# suppresses any "Segmentation fault" message there.  '((' could
+# trigger a bug in pdksh 5.2.14.
+for as_var in BASH_ENV ENV MAIL MAILPATH
+do eval test x\${$as_var+set} = xset \
+  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
+done
+PS1='$ '
+PS2='> '
+PS4='+ '
+
+# NLS nuisances.
+LC_ALL=C
+export LC_ALL
+LANGUAGE=C
+export LANGUAGE
+
+# CDPATH.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+# Use a proper internal environment variable to ensure we don't fall
+  # into an infinite loop, continuously re-executing ourselves.
+  if test x"${_as_can_reexec}" != xno && test "x$CONFIG_SHELL" != x; then
+    _as_can_reexec=no; export _as_can_reexec;
+    # We cannot yet assume a decent shell, so we have to provide a
+# neutralization value for shells without unset; and this also
+# works around shells that cannot unset nonexistent variables.
+# Preserve -v and -x to the replacement shell.
+BASH_ENV=/dev/null
+ENV=/dev/null
+(unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV
+case $- in # ((((
+  *v*x* | *x*v* ) as_opts=-vx ;;
+  *v* ) as_opts=-v ;;
+  *x* ) as_opts=-x ;;
+  * ) as_opts= ;;
+esac
+exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"}
+# Admittedly, this is quite paranoid, since all the known shells bail
+# out after a failed `exec'.
+$as_echo "$0: could not re-execute with $CONFIG_SHELL" >&2
+as_fn_exit 255
+  fi
+  # We don't want this to propagate to other subprocesses.
+          { _as_can_reexec=; unset _as_can_reexec;}
+if test "x$CONFIG_SHELL" = x; then
+  as_bourne_compatible="if test -n \"\${ZSH_VERSION+set}\" && (emulate sh) >/dev/null 2>&1; then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on \${1+\"\$@\"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '\${1+\"\$@\"}'='\"\$@\"'
+  setopt NO_GLOB_SUBST
+else
+  case \`(set -o) 2>/dev/null\` in #(
+  *posix*) :
+    set -o posix ;; #(
+  *) :
+     ;;
+esac
+fi
+"
+  as_required="as_fn_return () { (exit \$1); }
+as_fn_success () { as_fn_return 0; }
+as_fn_failure () { as_fn_return 1; }
+as_fn_ret_success () { return 0; }
+as_fn_ret_failure () { return 1; }
+
+exitcode=0
+as_fn_success || { exitcode=1; echo as_fn_success failed.; }
+as_fn_failure && { exitcode=1; echo as_fn_failure succeeded.; }
+as_fn_ret_success || { exitcode=1; echo as_fn_ret_success failed.; }
+as_fn_ret_failure && { exitcode=1; echo as_fn_ret_failure succeeded.; }
+if ( set x; as_fn_ret_success y && test x = \"\$1\" ); then :
+
+else
+  exitcode=1; echo positional parameters were not saved.
+fi
+test x\$exitcode = x0 || exit 1
+test -x / || exit 1"
+  as_suggested="  as_lineno_1=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_1a=\$LINENO
+  as_lineno_2=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_2a=\$LINENO
+  eval 'test \"x\$as_lineno_1'\$as_run'\" != \"x\$as_lineno_2'\$as_run'\" &&
+  test \"x\`expr \$as_lineno_1'\$as_run' + 1\`\" = \"x\$as_lineno_2'\$as_run'\"' || exit 1
+test \$(( 1 + 1 )) = 2 || exit 1
+
+  test -n \"\${ZSH_VERSION+set}\${BASH_VERSION+set}\" || (
+    ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
+    ECHO=\$ECHO\$ECHO\$ECHO\$ECHO\$ECHO
+    ECHO=\$ECHO\$ECHO\$ECHO\$ECHO\$ECHO\$ECHO
+    PATH=/empty FPATH=/empty; export PATH FPATH
+    test \"X\`printf %s \$ECHO\`\" = \"X\$ECHO\" \\
+      || test \"X\`print -r -- \$ECHO\`\" = \"X\$ECHO\" ) || exit 1"
+  if (eval "$as_required") 2>/dev/null; then :
+  as_have_required=yes
+else
+  as_have_required=no
+fi
+  if test x$as_have_required = xyes && (eval "$as_suggested") 2>/dev/null; then :
+
+else
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+as_found=false
+for as_dir in /bin$PATH_SEPARATOR/usr/bin$PATH_SEPARATOR$PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+  as_found=:
+  case $as_dir in #(
+	 /*)
+	   for as_base in sh bash ksh sh5; do
+	     # Try only shells that exist, to save several forks.
+	     as_shell=$as_dir/$as_base
+	     if { test -f "$as_shell" || test -f "$as_shell.exe"; } &&
+		    { $as_echo "$as_bourne_compatible""$as_required" | as_run=a "$as_shell"; } 2>/dev/null; then :
+  CONFIG_SHELL=$as_shell as_have_required=yes
+		   if { $as_echo "$as_bourne_compatible""$as_suggested" | as_run=a "$as_shell"; } 2>/dev/null; then :
+  break 2
+fi
+fi
+	   done;;
+       esac
+  as_found=false
+done
+$as_found || { if { test -f "$SHELL" || test -f "$SHELL.exe"; } &&
+	      { $as_echo "$as_bourne_compatible""$as_required" | as_run=a "$SHELL"; } 2>/dev/null; then :
+  CONFIG_SHELL=$SHELL as_have_required=yes
+fi; }
+IFS=$as_save_IFS
+
+
+      if test "x$CONFIG_SHELL" != x; then :
+  export CONFIG_SHELL
+             # We cannot yet assume a decent shell, so we have to provide a
+# neutralization value for shells without unset; and this also
+# works around shells that cannot unset nonexistent variables.
+# Preserve -v and -x to the replacement shell.
+BASH_ENV=/dev/null
+ENV=/dev/null
+(unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV
+case $- in # ((((
+  *v*x* | *x*v* ) as_opts=-vx ;;
+  *v* ) as_opts=-v ;;
+  *x* ) as_opts=-x ;;
+  * ) as_opts= ;;
+esac
+exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"}
+# Admittedly, this is quite paranoid, since all the known shells bail
+# out after a failed `exec'.
+$as_echo "$0: could not re-execute with $CONFIG_SHELL" >&2
+exit 255
+fi
+
+    if test x$as_have_required = xno; then :
+  $as_echo "$0: This script requires a shell more modern than all"
+  $as_echo "$0: the shells that I found on your system."
+  if test x${ZSH_VERSION+set} = xset ; then
+    $as_echo "$0: In particular, zsh $ZSH_VERSION has bugs and should"
+    $as_echo "$0: be upgraded to zsh 4.3.4 or later."
+  else
+    $as_echo "$0: Please tell bug-autoconf@gnu.org and
+$0: png-mng-implement@lists.sourceforge.net about your
+$0: system, including any error possibly output before this
+$0: message. Then install a modern shell, or manually run
+$0: the script under such a shell if you do have one."
+  fi
+  exit 1
+fi
+fi
+fi
+SHELL=${CONFIG_SHELL-/bin/sh}
+export SHELL
+# Unset more variables known to interfere with behavior of common tools.
+CLICOLOR_FORCE= GREP_OPTIONS=
+unset CLICOLOR_FORCE GREP_OPTIONS
+
+## --------------------- ##
+## M4sh Shell Functions. ##
+## --------------------- ##
+# as_fn_unset VAR
+# ---------------
+# Portably unset VAR.
+as_fn_unset ()
+{
+  { eval $1=; unset $1;}
+}
+as_unset=as_fn_unset
+
+# as_fn_set_status STATUS
+# -----------------------
+# Set $? to STATUS, without forking.
+as_fn_set_status ()
+{
+  return $1
+} # as_fn_set_status
+
+# as_fn_exit STATUS
+# -----------------
+# Exit the shell with STATUS, even in a "trap 0" or "set -e" context.
+as_fn_exit ()
+{
+  set +e
+  as_fn_set_status $1
+  exit $1
+} # as_fn_exit
+
+# as_fn_mkdir_p
+# -------------
+# Create "$as_dir" as a directory, including parents if necessary.
+as_fn_mkdir_p ()
+{
+
+  case $as_dir in #(
+  -*) as_dir=./$as_dir;;
+  esac
+  test -d "$as_dir" || eval $as_mkdir_p || {
+    as_dirs=
+    while :; do
+      case $as_dir in #(
+      *\'*) as_qdir=`$as_echo "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
+      *) as_qdir=$as_dir;;
+      esac
+      as_dirs="'$as_qdir' $as_dirs"
+      as_dir=`$as_dirname -- "$as_dir" ||
+$as_expr X"$as_dir" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$as_dir" : 'X\(//\)[^/]' \| \
+	 X"$as_dir" : 'X\(//\)$' \| \
+	 X"$as_dir" : 'X\(/\)' \| . 2>/dev/null ||
+$as_echo X"$as_dir" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+      test -d "$as_dir" && break
+    done
+    test -z "$as_dirs" || eval "mkdir $as_dirs"
+  } || test -d "$as_dir" || as_fn_error $? "cannot create directory $as_dir"
+
+
+} # as_fn_mkdir_p
+
+# as_fn_executable_p FILE
+# -----------------------
+# Test if FILE is an executable regular file.
+as_fn_executable_p ()
+{
+  test -f "$1" && test -x "$1"
+} # as_fn_executable_p
+# as_fn_append VAR VALUE
+# ----------------------
+# Append the text in VALUE to the end of the definition contained in VAR. Take
+# advantage of any shell optimizations that allow amortized linear growth over
+# repeated appends, instead of the typical quadratic growth present in naive
+# implementations.
+if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null; then :
+  eval 'as_fn_append ()
+  {
+    eval $1+=\$2
+  }'
+else
+  as_fn_append ()
+  {
+    eval $1=\$$1\$2
+  }
+fi # as_fn_append
+
+# as_fn_arith ARG...
+# ------------------
+# Perform arithmetic evaluation on the ARGs, and store the result in the
+# global $as_val. Take advantage of shells that can avoid forks. The arguments
+# must be portable across $(()) and expr.
+if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null; then :
+  eval 'as_fn_arith ()
+  {
+    as_val=$(( $* ))
+  }'
+else
+  as_fn_arith ()
+  {
+    as_val=`expr "$@" || test $? -eq 1`
+  }
+fi # as_fn_arith
+
+
+# as_fn_error STATUS ERROR [LINENO LOG_FD]
+# ----------------------------------------
+# Output "`basename $0`: error: ERROR" to stderr. If LINENO and LOG_FD are
+# provided, also output the error to LOG_FD, referencing LINENO. Then exit the
+# script with STATUS, using 1 if that was 0.
+as_fn_error ()
+{
+  as_status=$1; test $as_status -eq 0 && as_status=1
+  if test "$4"; then
+    as_lineno=${as_lineno-"$3"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+    $as_echo "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
+  fi
+  $as_echo "$as_me: error: $2" >&2
+  as_fn_exit $as_status
+} # as_fn_error
+
+if expr a : '\(a\)' >/dev/null 2>&1 &&
+   test "X`expr 00001 : '.*\(...\)'`" = X001; then
+  as_expr=expr
+else
+  as_expr=false
+fi
+
+if (basename -- /) >/dev/null 2>&1 && test "X`basename -- / 2>&1`" = "X/"; then
+  as_basename=basename
+else
+  as_basename=false
+fi
+
+if (as_dir=`dirname -- /` && test "X$as_dir" = X/) >/dev/null 2>&1; then
+  as_dirname=dirname
+else
+  as_dirname=false
+fi
+
+as_me=`$as_basename -- "$0" ||
+$as_expr X/"$0" : '.*/\([^/][^/]*\)/*$' \| \
+	 X"$0" : 'X\(//\)$' \| \
+	 X"$0" : 'X\(/\)' \| . 2>/dev/null ||
+$as_echo X/"$0" |
+    sed '/^.*\/\([^/][^/]*\)\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+
+# Avoid depending upon Character Ranges.
+as_cr_letters='abcdefghijklmnopqrstuvwxyz'
+as_cr_LETTERS='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+as_cr_Letters=$as_cr_letters$as_cr_LETTERS
+as_cr_digits='0123456789'
+as_cr_alnum=$as_cr_Letters$as_cr_digits
+
+
+  as_lineno_1=$LINENO as_lineno_1a=$LINENO
+  as_lineno_2=$LINENO as_lineno_2a=$LINENO
+  eval 'test "x$as_lineno_1'$as_run'" != "x$as_lineno_2'$as_run'" &&
+  test "x`expr $as_lineno_1'$as_run' + 1`" = "x$as_lineno_2'$as_run'"' || {
+  # Blame Lee E. McMahon (1931-1989) for sed's syntax.  :-)
+  sed -n '
+    p
+    /[$]LINENO/=
+  ' <$as_myself |
+    sed '
+      s/[$]LINENO.*/&-/
+      t lineno
+      b
+      :lineno
+      N
+      :loop
+      s/[$]LINENO\([^'$as_cr_alnum'_].*\n\)\(.*\)/\2\1\2/
+      t loop
+      s/-\n.*//
+    ' >$as_me.lineno &&
+  chmod +x "$as_me.lineno" ||
+    { $as_echo "$as_me: error: cannot create $as_me.lineno; rerun with a POSIX shell" >&2; as_fn_exit 1; }
+
+  # If we had to re-execute with $CONFIG_SHELL, we're ensured to have
+  # already done that, so ensure we don't try to do so again and fall
+  # in an infinite loop.  This has already happened in practice.
+  _as_can_reexec=no; export _as_can_reexec
+  # Don't try to exec as it changes $[0], causing all sort of problems
+  # (the dirname of $[0] is not the place where we might find the
+  # original and so on.  Autoconf is especially sensitive to this).
+  . "./$as_me.lineno"
+  # Exit status is that of the last command.
+  exit
+}
+
+ECHO_C= ECHO_N= ECHO_T=
+case `echo -n x` in #(((((
+-n*)
+  case `echo 'xy\c'` in
+  *c*) ECHO_T='	';;	# ECHO_T is single tab character.
+  xy)  ECHO_C='\c';;
+  *)   echo `echo ksh88 bug on AIX 6.1` > /dev/null
+       ECHO_T='	';;
+  esac;;
+*)
+  ECHO_N='-n';;
+esac
+
+rm -f conf$$ conf$$.exe conf$$.file
+if test -d conf$$.dir; then
+  rm -f conf$$.dir/conf$$.file
+else
+  rm -f conf$$.dir
+  mkdir conf$$.dir 2>/dev/null
+fi
+if (echo >conf$$.file) 2>/dev/null; then
+  if ln -s conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s='ln -s'
+    # ... but there are two gotchas:
+    # 1) On MSYS, both `ln -s file dir' and `ln file dir' fail.
+    # 2) DJGPP < 2.04 has no symlinks; `ln -s' creates a wrapper executable.
+    # In both cases, we have to default to `cp -pR'.
+    ln -s conf$$.file conf$$.dir 2>/dev/null && test ! -f conf$$.exe ||
+      as_ln_s='cp -pR'
+  elif ln conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s=ln
+  else
+    as_ln_s='cp -pR'
+  fi
+else
+  as_ln_s='cp -pR'
+fi
+rm -f conf$$ conf$$.exe conf$$.dir/conf$$.file conf$$.file
+rmdir conf$$.dir 2>/dev/null
+
+if mkdir -p . 2>/dev/null; then
+  as_mkdir_p='mkdir -p "$as_dir"'
+else
+  test -d ./-p && rmdir ./-p
+  as_mkdir_p=false
+fi
+
+as_test_x='test -x'
+as_executable_p=as_fn_executable_p
+
+# Sed expression to map a string onto a valid CPP name.
+as_tr_cpp="eval sed 'y%*$as_cr_letters%P$as_cr_LETTERS%;s%[^_$as_cr_alnum]%_%g'"
+
+# Sed expression to map a string onto a valid variable name.
+as_tr_sh="eval sed 'y%*+%pp%;s%[^_$as_cr_alnum]%_%g'"
+
+SHELL=${CONFIG_SHELL-/bin/sh}
+
+
+test -n "$DJDIR" || exec 7<&0 </dev/null
+exec 6>&1
+
+# Name of the host.
+# hostname on some systems (SVR3.2, old GNU/Linux) returns a bogus exit status,
+# so uname gets run too.
+ac_hostname=`(hostname || uname -n) 2>/dev/null | sed 1q`
+
+#
+# Initializations.
+#
+ac_default_prefix=/usr/local
+ac_clean_files=
+ac_config_libobj_dir=.
+LIBOBJS=
+cross_compiling=no
+subdirs=
+MFLAGS=
+MAKEFLAGS=
+
+# Identity of this package.
+PACKAGE_NAME='libpng'
+PACKAGE_TARNAME='libpng'
+PACKAGE_VERSION='1.6.37'
+PACKAGE_STRING='libpng 1.6.37'
+PACKAGE_BUGREPORT='png-mng-implement@lists.sourceforge.net'
+PACKAGE_URL=''
+
+ac_unique_file="pngget.c"
+# Factoring default headers for most tests.
+ac_includes_default="\
+#include <stdio.h>
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+#ifdef STDC_HEADERS
+# include <stdlib.h>
+# include <stddef.h>
+#else
+# ifdef HAVE_STDLIB_H
+#  include <stdlib.h>
+# endif
+#endif
+#ifdef HAVE_STRING_H
+# if !defined STDC_HEADERS && defined HAVE_MEMORY_H
+#  include <memory.h>
+# endif
+# include <string.h>
+#endif
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+# include <inttypes.h>
+#endif
+#ifdef HAVE_STDINT_H
+# include <stdint.h>
+#endif
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif"
+
+ac_subst_vars='am__EXEEXT_FALSE
+am__EXEEXT_TRUE
+LTLIBOBJS
+PNG_POWERPC_VSX_FALSE
+PNG_POWERPC_VSX_TRUE
+PNG_INTEL_SSE_FALSE
+PNG_INTEL_SSE_TRUE
+PNG_MIPS_MSA_FALSE
+PNG_MIPS_MSA_TRUE
+PNG_ARM_NEON_FALSE
+PNG_ARM_NEON_TRUE
+DO_INSTALL_LIBPNG_CONFIG_FALSE
+DO_INSTALL_LIBPNG_CONFIG_TRUE
+DO_INSTALL_LIBPNG_PC_FALSE
+DO_INSTALL_LIBPNG_PC_TRUE
+DO_INSTALL_LINKS_FALSE
+DO_INSTALL_LINKS_TRUE
+DO_PNG_PREFIX_FALSE
+DO_PNG_PREFIX_TRUE
+PNG_PREFIX
+binconfigs
+pkgconfigdir
+PNGLIB_RELEASE
+PNGLIB_MINOR
+PNGLIB_MAJOR
+PNGLIB_VERSION
+SYMBOL_PREFIX
+HAVE_LD_VERSION_SCRIPT_FALSE
+HAVE_LD_VERSION_SCRIPT_TRUE
+HAVE_SOLARIS_LD_FALSE
+HAVE_SOLARIS_LD_TRUE
+HAVE_CLOCK_GETTIME_FALSE
+HAVE_CLOCK_GETTIME_TRUE
+LIBOBJS
+POW_LIB
+PNG_COPTS
+DFNCPP
+LT_SYS_LIBRARY_PATH
+OTOOL64
+OTOOL
+LIPO
+NMEDIT
+DSYMUTIL
+MANIFEST_TOOL
+RANLIB
+ac_ct_AR
+AR
+NM
+ac_ct_DUMPBIN
+DUMPBIN
+LIBTOOL
+OBJDUMP
+DLLTOOL
+AS
+LN_S
+CPP
+LD
+FGREP
+EGREP
+GREP
+SED
+host_os
+host_vendor
+host_cpu
+host
+build_os
+build_vendor
+build_cpu
+build
+am__fastdepCCAS_FALSE
+am__fastdepCCAS_TRUE
+CCASDEPMODE
+CCASFLAGS
+CCAS
+am__fastdepCC_FALSE
+am__fastdepCC_TRUE
+CCDEPMODE
+am__nodep
+AMDEPBACKSLASH
+AMDEP_FALSE
+AMDEP_TRUE
+am__include
+DEPDIR
+OBJEXT
+EXEEXT
+ac_ct_CC
+CPPFLAGS
+LDFLAGS
+CFLAGS
+CC
+MAINT
+MAINTAINER_MODE_FALSE
+MAINTAINER_MODE_TRUE
+AM_BACKSLASH
+AM_DEFAULT_VERBOSITY
+AM_DEFAULT_V
+AM_V
+am__untar
+am__tar
+AMTAR
+am__leading_dot
+SET_MAKE
+AWK
+mkdir_p
+MKDIR_P
+INSTALL_STRIP_PROGRAM
+STRIP
+install_sh
+MAKEINFO
+AUTOHEADER
+AUTOMAKE
+AUTOCONF
+ACLOCAL
+VERSION
+PACKAGE
+CYGPATH_W
+am__isrc
+INSTALL_DATA
+INSTALL_SCRIPT
+INSTALL_PROGRAM
+target_alias
+host_alias
+build_alias
+LIBS
+ECHO_T
+ECHO_N
+ECHO_C
+DEFS
+mandir
+localedir
+libdir
+psdir
+pdfdir
+dvidir
+htmldir
+infodir
+docdir
+oldincludedir
+includedir
+localstatedir
+sharedstatedir
+sysconfdir
+datadir
+datarootdir
+libexecdir
+sbindir
+bindir
+program_transform_name
+prefix
+exec_prefix
+PACKAGE_URL
+PACKAGE_BUGREPORT
+PACKAGE_STRING
+PACKAGE_VERSION
+PACKAGE_TARNAME
+PACKAGE_NAME
+PATH_SEPARATOR
+SHELL
+am__quote'
+ac_subst_files=''
+ac_user_opts='
+enable_option_checking
+enable_silent_rules
+enable_maintainer_mode
+enable_dependency_tracking
+with_gnu_ld
+enable_shared
+enable_static
+with_pic
+enable_fast_install
+with_aix_soname
+with_sysroot
+enable_libtool_lock
+enable_werror
+with_zlib_prefix
+with_pkgconfigdir
+with_binconfigs
+with_libpng_prefix
+enable_unversioned_links
+enable_unversioned_libpng_pc
+enable_unversioned_libpng_config
+enable_hardware_optimizations
+enable_arm_neon
+enable_mips_msa
+enable_intel_sse
+enable_powerpc_vsx
+'
+      ac_precious_vars='build_alias
+host_alias
+target_alias
+CC
+CFLAGS
+LDFLAGS
+LIBS
+CPPFLAGS
+CCAS
+CCASFLAGS
+CPP
+LT_SYS_LIBRARY_PATH
+PNG_COPTS'
+
+
+# Initialize some variables set by options.
+ac_init_help=
+ac_init_version=false
+ac_unrecognized_opts=
+ac_unrecognized_sep=
+# The variables have the same names as the options, with
+# dashes changed to underlines.
+cache_file=/dev/null
+exec_prefix=NONE
+no_create=
+no_recursion=
+prefix=NONE
+program_prefix=NONE
+program_suffix=NONE
+program_transform_name=s,x,x,
+silent=
+site=
+srcdir=
+verbose=
+x_includes=NONE
+x_libraries=NONE
+
+# Installation directory options.
+# These are left unexpanded so users can "make install exec_prefix=/foo"
+# and all the variables that are supposed to be based on exec_prefix
+# by default will actually change.
+# Use braces instead of parens because sh, perl, etc. also accept them.
+# (The list follows the same order as the GNU Coding Standards.)
+bindir='${exec_prefix}/bin'
+sbindir='${exec_prefix}/sbin'
+libexecdir='${exec_prefix}/libexec'
+datarootdir='${prefix}/share'
+datadir='${datarootdir}'
+sysconfdir='${prefix}/etc'
+sharedstatedir='${prefix}/com'
+localstatedir='${prefix}/var'
+includedir='${prefix}/include'
+oldincludedir='/usr/include'
+docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
+infodir='${datarootdir}/info'
+htmldir='${docdir}'
+dvidir='${docdir}'
+pdfdir='${docdir}'
+psdir='${docdir}'
+libdir='${exec_prefix}/lib'
+localedir='${datarootdir}/locale'
+mandir='${datarootdir}/man'
+
+ac_prev=
+ac_dashdash=
+for ac_option
+do
+  # If the previous option needs an argument, assign it.
+  if test -n "$ac_prev"; then
+    eval $ac_prev=\$ac_option
+    ac_prev=
+    continue
+  fi
+
+  case $ac_option in
+  *=?*) ac_optarg=`expr "X$ac_option" : '[^=]*=\(.*\)'` ;;
+  *=)   ac_optarg= ;;
+  *)    ac_optarg=yes ;;
+  esac
+
+  # Accept the important Cygnus configure options, so we can diagnose typos.
+
+  case $ac_dashdash$ac_option in
+  --)
+    ac_dashdash=yes ;;
+
+  -bindir | --bindir | --bindi | --bind | --bin | --bi)
+    ac_prev=bindir ;;
+  -bindir=* | --bindir=* | --bindi=* | --bind=* | --bin=* | --bi=*)
+    bindir=$ac_optarg ;;
+
+  -build | --build | --buil | --bui | --bu)
+    ac_prev=build_alias ;;
+  -build=* | --build=* | --buil=* | --bui=* | --bu=*)
+    build_alias=$ac_optarg ;;
+
+  -cache-file | --cache-file | --cache-fil | --cache-fi \
+  | --cache-f | --cache- | --cache | --cach | --cac | --ca | --c)
+    ac_prev=cache_file ;;
+  -cache-file=* | --cache-file=* | --cache-fil=* | --cache-fi=* \
+  | --cache-f=* | --cache-=* | --cache=* | --cach=* | --cac=* | --ca=* | --c=*)
+    cache_file=$ac_optarg ;;
+
+  --config-cache | -C)
+    cache_file=config.cache ;;
+
+  -datadir | --datadir | --datadi | --datad)
+    ac_prev=datadir ;;
+  -datadir=* | --datadir=* | --datadi=* | --datad=*)
+    datadir=$ac_optarg ;;
+
+  -datarootdir | --datarootdir | --datarootdi | --datarootd | --dataroot \
+  | --dataroo | --dataro | --datar)
+    ac_prev=datarootdir ;;
+  -datarootdir=* | --datarootdir=* | --datarootdi=* | --datarootd=* \
+  | --dataroot=* | --dataroo=* | --dataro=* | --datar=*)
+    datarootdir=$ac_optarg ;;
+
+  -disable-* | --disable-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*disable-\(.*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid feature name: $ac_useropt"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"enable_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--disable-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval enable_$ac_useropt=no ;;
+
+  -docdir | --docdir | --docdi | --doc | --do)
+    ac_prev=docdir ;;
+  -docdir=* | --docdir=* | --docdi=* | --doc=* | --do=*)
+    docdir=$ac_optarg ;;
+
+  -dvidir | --dvidir | --dvidi | --dvid | --dvi | --dv)
+    ac_prev=dvidir ;;
+  -dvidir=* | --dvidir=* | --dvidi=* | --dvid=* | --dvi=* | --dv=*)
+    dvidir=$ac_optarg ;;
+
+  -enable-* | --enable-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*enable-\([^=]*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid feature name: $ac_useropt"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"enable_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--enable-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval enable_$ac_useropt=\$ac_optarg ;;
+
+  -exec-prefix | --exec_prefix | --exec-prefix | --exec-prefi \
+  | --exec-pref | --exec-pre | --exec-pr | --exec-p | --exec- \
+  | --exec | --exe | --ex)
+    ac_prev=exec_prefix ;;
+  -exec-prefix=* | --exec_prefix=* | --exec-prefix=* | --exec-prefi=* \
+  | --exec-pref=* | --exec-pre=* | --exec-pr=* | --exec-p=* | --exec-=* \
+  | --exec=* | --exe=* | --ex=*)
+    exec_prefix=$ac_optarg ;;
+
+  -gas | --gas | --ga | --g)
+    # Obsolete; use --with-gas.
+    with_gas=yes ;;
+
+  -help | --help | --hel | --he | -h)
+    ac_init_help=long ;;
+  -help=r* | --help=r* | --hel=r* | --he=r* | -hr*)
+    ac_init_help=recursive ;;
+  -help=s* | --help=s* | --hel=s* | --he=s* | -hs*)
+    ac_init_help=short ;;
+
+  -host | --host | --hos | --ho)
+    ac_prev=host_alias ;;
+  -host=* | --host=* | --hos=* | --ho=*)
+    host_alias=$ac_optarg ;;
+
+  -htmldir | --htmldir | --htmldi | --htmld | --html | --htm | --ht)
+    ac_prev=htmldir ;;
+  -htmldir=* | --htmldir=* | --htmldi=* | --htmld=* | --html=* | --htm=* \
+  | --ht=*)
+    htmldir=$ac_optarg ;;
+
+  -includedir | --includedir | --includedi | --included | --include \
+  | --includ | --inclu | --incl | --inc)
+    ac_prev=includedir ;;
+  -includedir=* | --includedir=* | --includedi=* | --included=* | --include=* \
+  | --includ=* | --inclu=* | --incl=* | --inc=*)
+    includedir=$ac_optarg ;;
+
+  -infodir | --infodir | --infodi | --infod | --info | --inf)
+    ac_prev=infodir ;;
+  -infodir=* | --infodir=* | --infodi=* | --infod=* | --info=* | --inf=*)
+    infodir=$ac_optarg ;;
+
+  -libdir | --libdir | --libdi | --libd)
+    ac_prev=libdir ;;
+  -libdir=* | --libdir=* | --libdi=* | --libd=*)
+    libdir=$ac_optarg ;;
+
+  -libexecdir | --libexecdir | --libexecdi | --libexecd | --libexec \
+  | --libexe | --libex | --libe)
+    ac_prev=libexecdir ;;
+  -libexecdir=* | --libexecdir=* | --libexecdi=* | --libexecd=* | --libexec=* \
+  | --libexe=* | --libex=* | --libe=*)
+    libexecdir=$ac_optarg ;;
+
+  -localedir | --localedir | --localedi | --localed | --locale)
+    ac_prev=localedir ;;
+  -localedir=* | --localedir=* | --localedi=* | --localed=* | --locale=*)
+    localedir=$ac_optarg ;;
+
+  -localstatedir | --localstatedir | --localstatedi | --localstated \
+  | --localstate | --localstat | --localsta | --localst | --locals)
+    ac_prev=localstatedir ;;
+  -localstatedir=* | --localstatedir=* | --localstatedi=* | --localstated=* \
+  | --localstate=* | --localstat=* | --localsta=* | --localst=* | --locals=*)
+    localstatedir=$ac_optarg ;;
+
+  -mandir | --mandir | --mandi | --mand | --man | --ma | --m)
+    ac_prev=mandir ;;
+  -mandir=* | --mandir=* | --mandi=* | --mand=* | --man=* | --ma=* | --m=*)
+    mandir=$ac_optarg ;;
+
+  -nfp | --nfp | --nf)
+    # Obsolete; use --without-fp.
+    with_fp=no ;;
+
+  -no-create | --no-create | --no-creat | --no-crea | --no-cre \
+  | --no-cr | --no-c | -n)
+    no_create=yes ;;
+
+  -no-recursion | --no-recursion | --no-recursio | --no-recursi \
+  | --no-recurs | --no-recur | --no-recu | --no-rec | --no-re | --no-r)
+    no_recursion=yes ;;
+
+  -oldincludedir | --oldincludedir | --oldincludedi | --oldincluded \
+  | --oldinclude | --oldinclud | --oldinclu | --oldincl | --oldinc \
+  | --oldin | --oldi | --old | --ol | --o)
+    ac_prev=oldincludedir ;;
+  -oldincludedir=* | --oldincludedir=* | --oldincludedi=* | --oldincluded=* \
+  | --oldinclude=* | --oldinclud=* | --oldinclu=* | --oldincl=* | --oldinc=* \
+  | --oldin=* | --oldi=* | --old=* | --ol=* | --o=*)
+    oldincludedir=$ac_optarg ;;
+
+  -prefix | --prefix | --prefi | --pref | --pre | --pr | --p)
+    ac_prev=prefix ;;
+  -prefix=* | --prefix=* | --prefi=* | --pref=* | --pre=* | --pr=* | --p=*)
+    prefix=$ac_optarg ;;
+
+  -program-prefix | --program-prefix | --program-prefi | --program-pref \
+  | --program-pre | --program-pr | --program-p)
+    ac_prev=program_prefix ;;
+  -program-prefix=* | --program-prefix=* | --program-prefi=* \
+  | --program-pref=* | --program-pre=* | --program-pr=* | --program-p=*)
+    program_prefix=$ac_optarg ;;
+
+  -program-suffix | --program-suffix | --program-suffi | --program-suff \
+  | --program-suf | --program-su | --program-s)
+    ac_prev=program_suffix ;;
+  -program-suffix=* | --program-suffix=* | --program-suffi=* \
+  | --program-suff=* | --program-suf=* | --program-su=* | --program-s=*)
+    program_suffix=$ac_optarg ;;
+
+  -program-transform-name | --program-transform-name \
+  | --program-transform-nam | --program-transform-na \
+  | --program-transform-n | --program-transform- \
+  | --program-transform | --program-transfor \
+  | --program-transfo | --program-transf \
+  | --program-trans | --program-tran \
+  | --progr-tra | --program-tr | --program-t)
+    ac_prev=program_transform_name ;;
+  -program-transform-name=* | --program-transform-name=* \
+  | --program-transform-nam=* | --program-transform-na=* \
+  | --program-transform-n=* | --program-transform-=* \
+  | --program-transform=* | --program-transfor=* \
+  | --program-transfo=* | --program-transf=* \
+  | --program-trans=* | --program-tran=* \
+  | --progr-tra=* | --program-tr=* | --program-t=*)
+    program_transform_name=$ac_optarg ;;
+
+  -pdfdir | --pdfdir | --pdfdi | --pdfd | --pdf | --pd)
+    ac_prev=pdfdir ;;
+  -pdfdir=* | --pdfdir=* | --pdfdi=* | --pdfd=* | --pdf=* | --pd=*)
+    pdfdir=$ac_optarg ;;
+
+  -psdir | --psdir | --psdi | --psd | --ps)
+    ac_prev=psdir ;;
+  -psdir=* | --psdir=* | --psdi=* | --psd=* | --ps=*)
+    psdir=$ac_optarg ;;
+
+  -q | -quiet | --quiet | --quie | --qui | --qu | --q \
+  | -silent | --silent | --silen | --sile | --sil)
+    silent=yes ;;
+
+  -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
+    ac_prev=sbindir ;;
+  -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
+  | --sbi=* | --sb=*)
+    sbindir=$ac_optarg ;;
+
+  -sharedstatedir | --sharedstatedir | --sharedstatedi \
+  | --sharedstated | --sharedstate | --sharedstat | --sharedsta \
+  | --sharedst | --shareds | --shared | --share | --shar \
+  | --sha | --sh)
+    ac_prev=sharedstatedir ;;
+  -sharedstatedir=* | --sharedstatedir=* | --sharedstatedi=* \
+  | --sharedstated=* | --sharedstate=* | --sharedstat=* | --sharedsta=* \
+  | --sharedst=* | --shareds=* | --shared=* | --share=* | --shar=* \
+  | --sha=* | --sh=*)
+    sharedstatedir=$ac_optarg ;;
+
+  -site | --site | --sit)
+    ac_prev=site ;;
+  -site=* | --site=* | --sit=*)
+    site=$ac_optarg ;;
+
+  -srcdir | --srcdir | --srcdi | --srcd | --src | --sr)
+    ac_prev=srcdir ;;
+  -srcdir=* | --srcdir=* | --srcdi=* | --srcd=* | --src=* | --sr=*)
+    srcdir=$ac_optarg ;;
+
+  -sysconfdir | --sysconfdir | --sysconfdi | --sysconfd | --sysconf \
+  | --syscon | --sysco | --sysc | --sys | --sy)
+    ac_prev=sysconfdir ;;
+  -sysconfdir=* | --sysconfdir=* | --sysconfdi=* | --sysconfd=* | --sysconf=* \
+  | --syscon=* | --sysco=* | --sysc=* | --sys=* | --sy=*)
+    sysconfdir=$ac_optarg ;;
+
+  -target | --target | --targe | --targ | --tar | --ta | --t)
+    ac_prev=target_alias ;;
+  -target=* | --target=* | --targe=* | --targ=* | --tar=* | --ta=* | --t=*)
+    target_alias=$ac_optarg ;;
+
+  -v | -verbose | --verbose | --verbos | --verbo | --verb)
+    verbose=yes ;;
+
+  -version | --version | --versio | --versi | --vers | -V)
+    ac_init_version=: ;;
+
+  -with-* | --with-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*with-\([^=]*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid package name: $ac_useropt"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"with_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--with-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval with_$ac_useropt=\$ac_optarg ;;
+
+  -without-* | --without-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*without-\(.*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid package name: $ac_useropt"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"with_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--without-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval with_$ac_useropt=no ;;
+
+  --x)
+    # Obsolete; use --with-x.
+    with_x=yes ;;
+
+  -x-includes | --x-includes | --x-include | --x-includ | --x-inclu \
+  | --x-incl | --x-inc | --x-in | --x-i)
+    ac_prev=x_includes ;;
+  -x-includes=* | --x-includes=* | --x-include=* | --x-includ=* | --x-inclu=* \
+  | --x-incl=* | --x-inc=* | --x-in=* | --x-i=*)
+    x_includes=$ac_optarg ;;
+
+  -x-libraries | --x-libraries | --x-librarie | --x-librari \
+  | --x-librar | --x-libra | --x-libr | --x-lib | --x-li | --x-l)
+    ac_prev=x_libraries ;;
+  -x-libraries=* | --x-libraries=* | --x-librarie=* | --x-librari=* \
+  | --x-librar=* | --x-libra=* | --x-libr=* | --x-lib=* | --x-li=* | --x-l=*)
+    x_libraries=$ac_optarg ;;
+
+  -*) as_fn_error $? "unrecognized option: \`$ac_option'
+Try \`$0 --help' for more information"
+    ;;
+
+  *=*)
+    ac_envvar=`expr "x$ac_option" : 'x\([^=]*\)='`
+    # Reject names that are not valid shell variable names.
+    case $ac_envvar in #(
+      '' | [0-9]* | *[!_$as_cr_alnum]* )
+      as_fn_error $? "invalid variable name: \`$ac_envvar'" ;;
+    esac
+    eval $ac_envvar=\$ac_optarg
+    export $ac_envvar ;;
+
+  *)
+    # FIXME: should be removed in autoconf 3.0.
+    $as_echo "$as_me: WARNING: you should use --build, --host, --target" >&2
+    expr "x$ac_option" : ".*[^-._$as_cr_alnum]" >/dev/null &&
+      $as_echo "$as_me: WARNING: invalid host type: $ac_option" >&2
+    : "${build_alias=$ac_option} ${host_alias=$ac_option} ${target_alias=$ac_option}"
+    ;;
+
+  esac
+done
+
+if test -n "$ac_prev"; then
+  ac_option=--`echo $ac_prev | sed 's/_/-/g'`
+  as_fn_error $? "missing argument to $ac_option"
+fi
+
+if test -n "$ac_unrecognized_opts"; then
+  case $enable_option_checking in
+    no) ;;
+    fatal) as_fn_error $? "unrecognized options: $ac_unrecognized_opts" ;;
+    *)     $as_echo "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2 ;;
+  esac
+fi
+
+# Check all directory arguments for consistency.
+for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
+		datadir sysconfdir sharedstatedir localstatedir includedir \
+		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
+		libdir localedir mandir
+do
+  eval ac_val=\$$ac_var
+  # Remove trailing slashes.
+  case $ac_val in
+    */ )
+      ac_val=`expr "X$ac_val" : 'X\(.*[^/]\)' \| "X$ac_val" : 'X\(.*\)'`
+      eval $ac_var=\$ac_val;;
+  esac
+  # Be sure to have absolute directory names.
+  case $ac_val in
+    [\\/$]* | ?:[\\/]* )  continue;;
+    NONE | '' ) case $ac_var in *prefix ) continue;; esac;;
+  esac
+  as_fn_error $? "expected an absolute directory name for --$ac_var: $ac_val"
+done
+
+# There might be people who depend on the old broken behavior: `$host'
+# used to hold the argument of --host etc.
+# FIXME: To remove some day.
+build=$build_alias
+host=$host_alias
+target=$target_alias
+
+# FIXME: To remove some day.
+if test "x$host_alias" != x; then
+  if test "x$build_alias" = x; then
+    cross_compiling=maybe
+  elif test "x$build_alias" != "x$host_alias"; then
+    cross_compiling=yes
+  fi
+fi
+
+ac_tool_prefix=
+test -n "$host_alias" && ac_tool_prefix=$host_alias-
+
+test "$silent" = yes && exec 6>/dev/null
+
+
+ac_pwd=`pwd` && test -n "$ac_pwd" &&
+ac_ls_di=`ls -di .` &&
+ac_pwd_ls_di=`cd "$ac_pwd" && ls -di .` ||
+  as_fn_error $? "working directory cannot be determined"
+test "X$ac_ls_di" = "X$ac_pwd_ls_di" ||
+  as_fn_error $? "pwd does not report name of working directory"
+
+
+# Find the source files, if location was not specified.
+if test -z "$srcdir"; then
+  ac_srcdir_defaulted=yes
+  # Try the directory containing this script, then the parent directory.
+  ac_confdir=`$as_dirname -- "$as_myself" ||
+$as_expr X"$as_myself" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$as_myself" : 'X\(//\)[^/]' \| \
+	 X"$as_myself" : 'X\(//\)$' \| \
+	 X"$as_myself" : 'X\(/\)' \| . 2>/dev/null ||
+$as_echo X"$as_myself" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+  srcdir=$ac_confdir
+  if test ! -r "$srcdir/$ac_unique_file"; then
+    srcdir=..
+  fi
+else
+  ac_srcdir_defaulted=no
+fi
+if test ! -r "$srcdir/$ac_unique_file"; then
+  test "$ac_srcdir_defaulted" = yes && srcdir="$ac_confdir or .."
+  as_fn_error $? "cannot find sources ($ac_unique_file) in $srcdir"
+fi
+ac_msg="sources are in $srcdir, but \`cd $srcdir' does not work"
+ac_abs_confdir=`(
+	cd "$srcdir" && test -r "./$ac_unique_file" || as_fn_error $? "$ac_msg"
+	pwd)`
+# When building in place, set srcdir=.
+if test "$ac_abs_confdir" = "$ac_pwd"; then
+  srcdir=.
+fi
+# Remove unnecessary trailing slashes from srcdir.
+# Double slashes in file names in object file debugging info
+# mess up M-x gdb in Emacs.
+case $srcdir in
+*/) srcdir=`expr "X$srcdir" : 'X\(.*[^/]\)' \| "X$srcdir" : 'X\(.*\)'`;;
+esac
+for ac_var in $ac_precious_vars; do
+  eval ac_env_${ac_var}_set=\${${ac_var}+set}
+  eval ac_env_${ac_var}_value=\$${ac_var}
+  eval ac_cv_env_${ac_var}_set=\${${ac_var}+set}
+  eval ac_cv_env_${ac_var}_value=\$${ac_var}
+done
+
+#
+# Report the --help message.
+#
+if test "$ac_init_help" = "long"; then
+  # Omit some internal or obsolete options to make the list less imposing.
+  # This message is too long to be a string in the A/UX 3.1 sh.
+  cat <<_ACEOF
+\`configure' configures libpng 1.6.37 to adapt to many kinds of systems.
+
+Usage: $0 [OPTION]... [VAR=VALUE]...
+
+To assign environment variables (e.g., CC, CFLAGS...), specify them as
+VAR=VALUE.  See below for descriptions of some of the useful variables.
+
+Defaults for the options are specified in brackets.
+
+Configuration:
+  -h, --help              display this help and exit
+      --help=short        display options specific to this package
+      --help=recursive    display the short help of all the included packages
+  -V, --version           display version information and exit
+  -q, --quiet, --silent   do not print \`checking ...' messages
+      --cache-file=FILE   cache test results in FILE [disabled]
+  -C, --config-cache      alias for \`--cache-file=config.cache'
+  -n, --no-create         do not create output files
+      --srcdir=DIR        find the sources in DIR [configure dir or \`..']
+
+Installation directories:
+  --prefix=PREFIX         install architecture-independent files in PREFIX
+                          [$ac_default_prefix]
+  --exec-prefix=EPREFIX   install architecture-dependent files in EPREFIX
+                          [PREFIX]
+
+By default, \`make install' will install all the files in
+\`$ac_default_prefix/bin', \`$ac_default_prefix/lib' etc.  You can specify
+an installation prefix other than \`$ac_default_prefix' using \`--prefix',
+for instance \`--prefix=\$HOME'.
+
+For better control, use the options below.
+
+Fine tuning of the installation directories:
+  --bindir=DIR            user executables [EPREFIX/bin]
+  --sbindir=DIR           system admin executables [EPREFIX/sbin]
+  --libexecdir=DIR        program executables [EPREFIX/libexec]
+  --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
+  --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
+  --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --libdir=DIR            object code libraries [EPREFIX/lib]
+  --includedir=DIR        C header files [PREFIX/include]
+  --oldincludedir=DIR     C header files for non-gcc [/usr/include]
+  --datarootdir=DIR       read-only arch.-independent data root [PREFIX/share]
+  --datadir=DIR           read-only architecture-independent data [DATAROOTDIR]
+  --infodir=DIR           info documentation [DATAROOTDIR/info]
+  --localedir=DIR         locale-dependent data [DATAROOTDIR/locale]
+  --mandir=DIR            man documentation [DATAROOTDIR/man]
+  --docdir=DIR            documentation root [DATAROOTDIR/doc/libpng]
+  --htmldir=DIR           html documentation [DOCDIR]
+  --dvidir=DIR            dvi documentation [DOCDIR]
+  --pdfdir=DIR            pdf documentation [DOCDIR]
+  --psdir=DIR             ps documentation [DOCDIR]
+_ACEOF
+
+  cat <<\_ACEOF
+
+Program names:
+  --program-prefix=PREFIX            prepend PREFIX to installed program names
+  --program-suffix=SUFFIX            append SUFFIX to installed program names
+  --program-transform-name=PROGRAM   run sed PROGRAM on installed program names
+
+System types:
+  --build=BUILD     configure for building on BUILD [guessed]
+  --host=HOST       cross-compile to build programs to run on HOST [BUILD]
+_ACEOF
+fi
+
+if test -n "$ac_init_help"; then
+  case $ac_init_help in
+     short | recursive ) echo "Configuration of libpng 1.6.37:";;
+   esac
+  cat <<\_ACEOF
+
+Optional Features:
+  --disable-option-checking  ignore unrecognized --enable/--with options
+  --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
+  --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
+  --enable-silent-rules   less verbose build output (undo: "make V=1")
+  --disable-silent-rules  verbose build output (undo: "make V=0")
+  --enable-maintainer-mode
+                          enable make rules and dependencies not useful (and
+                          sometimes confusing) to the casual installer
+  --enable-dependency-tracking
+                          do not reject slow dependency extractors
+  --disable-dependency-tracking
+                          speeds up one-time build
+  --enable-shared[=PKGS]  build shared libraries [default=yes]
+  --enable-static[=PKGS]  build static libraries [default=yes]
+  --enable-fast-install[=PKGS]
+                          optimize for fast installation [default=yes]
+  --disable-libtool-lock  avoid locking (might break parallel builds)
+  --enable-werror[=OPT] Pass -Werror or the given argument to the compiler
+                          if it is supported
+  --enable-unversioned-links
+                          Installed libpng header files are placed in a
+                          versioned subdirectory and installed libpng library
+                          (including DLL) files are versioned. If this option
+                          is enabled unversioned links will be created
+                          pointing to the corresponding installed files. If
+                          you use libpng.pc or libpng-config for all builds
+                          you do not need these links, but if you compile
+                          programs directly they will typically #include
+                          <png.h> and link with -lpng; in that case you need
+                          the links. The links can be installed manually using
+                          'make install-header-links' and 'make
+                          install-library-links' and can be removed using the
+                          corresponding uninstall- targets. If you do enable
+                          this option every libpng 'make install' will
+                          recreate the links to point to the just installed
+                          version of libpng. The default is to create the
+                          links; use --disable-unversioned-links to change
+                          this
+  --enable-unversioned-libpng-pc
+                          Install the configuration file 'libpng.pc' as a link
+                          to the versioned version. This is done by default -
+                          use --disable-unversioned-libpng-pc to change this.
+  --enable-unversioned-libpng-config
+                          Install the configuration file 'libpng-config' as a
+                          link to the versioned version. This is done by
+                          default - use --disable-unversioned-libpng-config to
+                          change this.
+  --enable-hardware-optimizations
+                          Enable hardware optimizations: =no/off, yes/on:
+  --enable-arm-neon     Enable ARM NEON optimizations: =no/off, check, api,
+                          yes/on: no/off: disable the optimizations; check:
+                          use internal checking code (deprecated and poorly
+                          supported); api: disable by default, enable by a
+                          call to png_set_option; yes/on: turn on
+                          unconditionally. If not specified: determined by the
+                          compiler.
+  --enable-mips-msa     Enable MIPS MSA optimizations: =no/off, check, api,
+                          yes/on: no/off: disable the optimizations; check:
+                          use internal checking code (deprecated and poorly
+                          supported); api: disable by default, enable by a
+                          call to png_set_option; yes/on: turn on
+                          unconditionally. If not specified: determined by the
+                          compiler.
+  --enable-intel-sse    Enable Intel SSE optimizations: =no/off, yes/on:
+                          no/off: disable the optimizations; yes/on: enable
+                          the optimizations. If not specified: determined by
+                          the compiler.
+  --enable-powerpc-vsx  Enable POWERPC VSX optimizations: =no/off, check,
+                          api, yes/on: no/off: disable the optimizations;
+                          check: use internal checking code api: disable by
+                          default, enable by a call to png_set_option yes/on:
+                          turn on unconditionally. If not specified:
+                          determined by the compiler.
+
+Optional Packages:
+  --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
+  --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
+  --with-gnu-ld           assume the C compiler uses GNU ld [default=no]
+  --with-pic[=PKGS]       try to use only PIC/non-PIC objects [default=use
+                          both]
+  --with-aix-soname=aix|svr4|both
+                          shared library versioning (aka "SONAME") variant to
+                          provide on AIX, [default=aix].
+  --with-sysroot[=DIR]    Search for dependent libraries within DIR (or the
+                          compiler's sysroot if not specified).
+  --with-zlib-prefix    prefix that may have been used in installed zlib
+  --with-pkgconfigdir   Use the specified pkgconfig dir (default is
+                          libdir/pkgconfig)
+  --with-binconfigs     Generate shell libpng-config scripts as well as
+                          pkg-config data [default=yes]
+  --with-libpng-prefix  prefix libpng exported function (API) names with the
+                          given value
+
+Some influential environment variables:
+  CC          C compiler command
+  CFLAGS      C compiler flags
+  LDFLAGS     linker flags, e.g. -L<lib dir> if you have libraries in a
+              nonstandard directory <lib dir>
+  LIBS        libraries to pass to the linker, e.g. -l<library>
+  CPPFLAGS    (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
+              you have headers in a nonstandard directory <include dir>
+  CCAS        assembler compiler command (defaults to CC)
+  CCASFLAGS   assembler compiler flags (defaults to CFLAGS)
+  CPP         C preprocessor
+  LT_SYS_LIBRARY_PATH
+              User-defined run-time library search path.
+  PNG_COPTS   additional flags for the C compiler, use this for options that
+              would cause configure itself to fail
+
+Use these variables to override the choices made by `configure' or to help
+it to find libraries and programs with nonstandard names/locations.
+
+Report bugs to <png-mng-implement@lists.sourceforge.net>.
+_ACEOF
+ac_status=$?
+fi
+
+if test "$ac_init_help" = "recursive"; then
+  # If there are subdirs, report their specific --help.
+  for ac_dir in : $ac_subdirs_all; do test "x$ac_dir" = x: && continue
+    test -d "$ac_dir" ||
+      { cd "$srcdir" && ac_pwd=`pwd` && srcdir=. && test -d "$ac_dir"; } ||
+      continue
+    ac_builddir=.
+
+case "$ac_dir" in
+.) ac_dir_suffix= ac_top_builddir_sub=. ac_top_build_prefix= ;;
+*)
+  ac_dir_suffix=/`$as_echo "$ac_dir" | sed 's|^\.[\\/]||'`
+  # A ".." for each directory in $ac_dir_suffix.
+  ac_top_builddir_sub=`$as_echo "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
+  case $ac_top_builddir_sub in
+  "") ac_top_builddir_sub=. ac_top_build_prefix= ;;
+  *)  ac_top_build_prefix=$ac_top_builddir_sub/ ;;
+  esac ;;
+esac
+ac_abs_top_builddir=$ac_pwd
+ac_abs_builddir=$ac_pwd$ac_dir_suffix
+# for backward compatibility:
+ac_top_builddir=$ac_top_build_prefix
+
+case $srcdir in
+  .)  # We are building in place.
+    ac_srcdir=.
+    ac_top_srcdir=$ac_top_builddir_sub
+    ac_abs_top_srcdir=$ac_pwd ;;
+  [\\/]* | ?:[\\/]* )  # Absolute name.
+    ac_srcdir=$srcdir$ac_dir_suffix;
+    ac_top_srcdir=$srcdir
+    ac_abs_top_srcdir=$srcdir ;;
+  *) # Relative name.
+    ac_srcdir=$ac_top_build_prefix$srcdir$ac_dir_suffix
+    ac_top_srcdir=$ac_top_build_prefix$srcdir
+    ac_abs_top_srcdir=$ac_pwd/$srcdir ;;
+esac
+ac_abs_srcdir=$ac_abs_top_srcdir$ac_dir_suffix
+
+    cd "$ac_dir" || { ac_status=$?; continue; }
+    # Check for guested configure.
+    if test -f "$ac_srcdir/configure.gnu"; then
+      echo &&
+      $SHELL "$ac_srcdir/configure.gnu" --help=recursive
+    elif test -f "$ac_srcdir/configure"; then
+      echo &&
+      $SHELL "$ac_srcdir/configure" --help=recursive
+    else
+      $as_echo "$as_me: WARNING: no configuration information is in $ac_dir" >&2
+    fi || ac_status=$?
+    cd "$ac_pwd" || { ac_status=$?; break; }
+  done
+fi
+
+test -n "$ac_init_help" && exit $ac_status
+if $ac_init_version; then
+  cat <<\_ACEOF
+libpng configure 1.6.37
+generated by GNU Autoconf 2.69
+
+Copyright (C) 2012 Free Software Foundation, Inc.
+This configure script is free software; the Free Software Foundation
+gives unlimited permission to copy, distribute and modify it.
+_ACEOF
+  exit
+fi
+
+## ------------------------ ##
+## Autoconf initialization. ##
+## ------------------------ ##
+
+# ac_fn_c_try_compile LINENO
+# --------------------------
+# Try to compile conftest.$ac_ext, and return whether this succeeded.
+ac_fn_c_try_compile ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  rm -f conftest.$ac_objext
+  if { { ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_compile") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    grep -v '^ *+' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+    mv -f conftest.er1 conftest.err
+  fi
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest.$ac_objext; then :
+  ac_retval=0
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_retval=1
+fi
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_compile
+
+# ac_fn_c_try_cpp LINENO
+# ----------------------
+# Try to preprocess conftest.$ac_ext, and return whether this succeeded.
+ac_fn_c_try_cpp ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  if { { ac_try="$ac_cpp conftest.$ac_ext"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_cpp conftest.$ac_ext") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    grep -v '^ *+' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+    mv -f conftest.er1 conftest.err
+  fi
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } > conftest.i && {
+	 test -z "$ac_c_preproc_warn_flag$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       }; then :
+  ac_retval=0
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+    ac_retval=1
+fi
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_cpp
+
+# ac_fn_c_try_link LINENO
+# -----------------------
+# Try to link conftest.$ac_ext, and return whether this succeeded.
+ac_fn_c_try_link ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  rm -f conftest.$ac_objext conftest$ac_exeext
+  if { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    grep -v '^ *+' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+    mv -f conftest.er1 conftest.err
+  fi
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext && {
+	 test "$cross_compiling" = yes ||
+	 test -x conftest$ac_exeext
+       }; then :
+  ac_retval=0
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_retval=1
+fi
+  # Delete the IPA/IPO (Inter Procedural Analysis/Optimization) information
+  # created by the PGI compiler (conftest_ipa8_conftest.oo), as it would
+  # interfere with the next link command; also delete a directory that is
+  # left behind by Apple's compiler.  We do this before executing the actions.
+  rm -rf conftest.dSYM conftest_ipa8_conftest.oo
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_link
+
+# ac_fn_c_check_header_compile LINENO HEADER VAR INCLUDES
+# -------------------------------------------------------
+# Tests whether HEADER exists and can be compiled using the include files in
+# INCLUDES, setting the cache variable VAR accordingly.
+ac_fn_c_check_header_compile ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
+$as_echo_n "checking for $2... " >&6; }
+if eval \${$3+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$4
+#include <$2>
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  eval "$3=yes"
+else
+  eval "$3=no"
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+eval ac_res=\$$3
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_c_check_header_compile
+
+# ac_fn_c_try_run LINENO
+# ----------------------
+# Try to link conftest.$ac_ext, and return whether this succeeded. Assumes
+# that executables *can* be run.
+ac_fn_c_try_run ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  if { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && { ac_try='./conftest$ac_exeext'
+  { { case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }; then :
+  ac_retval=0
+else
+  $as_echo "$as_me: program exited with status $ac_status" >&5
+       $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+       ac_retval=$ac_status
+fi
+  rm -rf conftest.dSYM conftest_ipa8_conftest.oo
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_run
+
+# ac_fn_c_check_func LINENO FUNC VAR
+# ----------------------------------
+# Tests whether FUNC exists, setting the cache variable VAR accordingly
+ac_fn_c_check_func ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
+$as_echo_n "checking for $2... " >&6; }
+if eval \${$3+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+/* Define $2 to an innocuous variant, in case <limits.h> declares $2.
+   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
+#define $2 innocuous_$2
+
+/* System header to define __stub macros and hopefully few prototypes,
+    which can conflict with char $2 (); below.
+    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+    <limits.h> exists even on freestanding compilers.  */
+
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+
+#undef $2
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char $2 ();
+/* The GNU C library defines this for functions which it implements
+    to always fail with ENOSYS.  Some functions are actually named
+    something starting with __ and the normal name is an alias.  */
+#if defined __stub_$2 || defined __stub___$2
+choke me
+#endif
+
+int
+main ()
+{
+return $2 ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  eval "$3=yes"
+else
+  eval "$3=no"
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+fi
+eval ac_res=\$$3
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_c_check_func
+
+# ac_fn_c_check_type LINENO TYPE VAR INCLUDES
+# -------------------------------------------
+# Tests whether TYPE exists after having included INCLUDES, setting cache
+# variable VAR accordingly.
+ac_fn_c_check_type ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
+$as_echo_n "checking for $2... " >&6; }
+if eval \${$3+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  eval "$3=no"
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$4
+int
+main ()
+{
+if (sizeof ($2))
+	 return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$4
+int
+main ()
+{
+if (sizeof (($2)))
+	    return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+else
+  eval "$3=yes"
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+eval ac_res=\$$3
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_c_check_type
+cat >config.log <<_ACEOF
+This file contains any messages produced by compilers while
+running configure, to aid debugging if configure makes a mistake.
+
+It was created by libpng $as_me 1.6.37, which was
+generated by GNU Autoconf 2.69.  Invocation command line was
+
+  $ $0 $@
+
+_ACEOF
+exec 5>>config.log
+{
+cat <<_ASUNAME
+## --------- ##
+## Platform. ##
+## --------- ##
+
+hostname = `(hostname || uname -n) 2>/dev/null | sed 1q`
+uname -m = `(uname -m) 2>/dev/null || echo unknown`
+uname -r = `(uname -r) 2>/dev/null || echo unknown`
+uname -s = `(uname -s) 2>/dev/null || echo unknown`
+uname -v = `(uname -v) 2>/dev/null || echo unknown`
+
+/usr/bin/uname -p = `(/usr/bin/uname -p) 2>/dev/null || echo unknown`
+/bin/uname -X     = `(/bin/uname -X) 2>/dev/null     || echo unknown`
+
+/bin/arch              = `(/bin/arch) 2>/dev/null              || echo unknown`
+/usr/bin/arch -k       = `(/usr/bin/arch -k) 2>/dev/null       || echo unknown`
+/usr/convex/getsysinfo = `(/usr/convex/getsysinfo) 2>/dev/null || echo unknown`
+/usr/bin/hostinfo      = `(/usr/bin/hostinfo) 2>/dev/null      || echo unknown`
+/bin/machine           = `(/bin/machine) 2>/dev/null           || echo unknown`
+/usr/bin/oslevel       = `(/usr/bin/oslevel) 2>/dev/null       || echo unknown`
+/bin/universe          = `(/bin/universe) 2>/dev/null          || echo unknown`
+
+_ASUNAME
+
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    $as_echo "PATH: $as_dir"
+  done
+IFS=$as_save_IFS
+
+} >&5
+
+cat >&5 <<_ACEOF
+
+
+## ----------- ##
+## Core tests. ##
+## ----------- ##
+
+_ACEOF
+
+
+# Keep a trace of the command line.
+# Strip out --no-create and --no-recursion so they do not pile up.
+# Strip out --silent because we don't want to record it for future runs.
+# Also quote any args containing shell meta-characters.
+# Make two passes to allow for proper duplicate-argument suppression.
+ac_configure_args=
+ac_configure_args0=
+ac_configure_args1=
+ac_must_keep_next=false
+for ac_pass in 1 2
+do
+  for ac_arg
+  do
+    case $ac_arg in
+    -no-create | --no-c* | -n | -no-recursion | --no-r*) continue ;;
+    -q | -quiet | --quiet | --quie | --qui | --qu | --q \
+    | -silent | --silent | --silen | --sile | --sil)
+      continue ;;
+    *\'*)
+      ac_arg=`$as_echo "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    esac
+    case $ac_pass in
+    1) as_fn_append ac_configure_args0 " '$ac_arg'" ;;
+    2)
+      as_fn_append ac_configure_args1 " '$ac_arg'"
+      if test $ac_must_keep_next = true; then
+	ac_must_keep_next=false # Got value, back to normal.
+      else
+	case $ac_arg in
+	  *=* | --config-cache | -C | -disable-* | --disable-* \
+	  | -enable-* | --enable-* | -gas | --g* | -nfp | --nf* \
+	  | -q | -quiet | --q* | -silent | --sil* | -v | -verb* \
+	  | -with-* | --with-* | -without-* | --without-* | --x)
+	    case "$ac_configure_args0 " in
+	      "$ac_configure_args1"*" '$ac_arg' "* ) continue ;;
+	    esac
+	    ;;
+	  -* ) ac_must_keep_next=true ;;
+	esac
+      fi
+      as_fn_append ac_configure_args " '$ac_arg'"
+      ;;
+    esac
+  done
+done
+{ ac_configure_args0=; unset ac_configure_args0;}
+{ ac_configure_args1=; unset ac_configure_args1;}
+
+# When interrupted or exit'd, cleanup temporary files, and complete
+# config.log.  We remove comments because anyway the quotes in there
+# would cause problems or look ugly.
+# WARNING: Use '\'' to represent an apostrophe within the trap.
+# WARNING: Do not start the trap code with a newline, due to a FreeBSD 4.0 bug.
+trap 'exit_status=$?
+  # Save into config.log some information that might help in debugging.
+  {
+    echo
+
+    $as_echo "## ---------------- ##
+## Cache variables. ##
+## ---------------- ##"
+    echo
+    # The following way of writing the cache mishandles newlines in values,
+(
+  for ac_var in `(set) 2>&1 | sed -n '\''s/^\([a-zA-Z_][a-zA-Z0-9_]*\)=.*/\1/p'\''`; do
+    eval ac_val=\$$ac_var
+    case $ac_val in #(
+    *${as_nl}*)
+      case $ac_var in #(
+      *_cv_*) { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
+$as_echo "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
+      esac
+      case $ac_var in #(
+      _ | IFS | as_nl) ;; #(
+      BASH_ARGV | BASH_SOURCE) eval $ac_var= ;; #(
+      *) { eval $ac_var=; unset $ac_var;} ;;
+      esac ;;
+    esac
+  done
+  (set) 2>&1 |
+    case $as_nl`(ac_space='\'' '\''; set) 2>&1` in #(
+    *${as_nl}ac_space=\ *)
+      sed -n \
+	"s/'\''/'\''\\\\'\'''\''/g;
+	  s/^\\([_$as_cr_alnum]*_cv_[_$as_cr_alnum]*\\)=\\(.*\\)/\\1='\''\\2'\''/p"
+      ;; #(
+    *)
+      sed -n "/^[_$as_cr_alnum]*_cv_[_$as_cr_alnum]*=/p"
+      ;;
+    esac |
+    sort
+)
+    echo
+
+    $as_echo "## ----------------- ##
+## Output variables. ##
+## ----------------- ##"
+    echo
+    for ac_var in $ac_subst_vars
+    do
+      eval ac_val=\$$ac_var
+      case $ac_val in
+      *\'\''*) ac_val=`$as_echo "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
+      esac
+      $as_echo "$ac_var='\''$ac_val'\''"
+    done | sort
+    echo
+
+    if test -n "$ac_subst_files"; then
+      $as_echo "## ------------------- ##
+## File substitutions. ##
+## ------------------- ##"
+      echo
+      for ac_var in $ac_subst_files
+      do
+	eval ac_val=\$$ac_var
+	case $ac_val in
+	*\'\''*) ac_val=`$as_echo "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
+	esac
+	$as_echo "$ac_var='\''$ac_val'\''"
+      done | sort
+      echo
+    fi
+
+    if test -s confdefs.h; then
+      $as_echo "## ----------- ##
+## confdefs.h. ##
+## ----------- ##"
+      echo
+      cat confdefs.h
+      echo
+    fi
+    test "$ac_signal" != 0 &&
+      $as_echo "$as_me: caught signal $ac_signal"
+    $as_echo "$as_me: exit $exit_status"
+  } >&5
+  rm -f core *.core core.conftest.* &&
+    rm -f -r conftest* confdefs* conf$$* $ac_clean_files &&
+    exit $exit_status
+' 0
+for ac_signal in 1 2 13 15; do
+  trap 'ac_signal='$ac_signal'; as_fn_exit 1' $ac_signal
+done
+ac_signal=0
+
+# confdefs.h avoids OS command line length limits that DEFS can exceed.
+rm -f -r conftest* confdefs.h
+
+$as_echo "/* confdefs.h */" > confdefs.h
+
+# Predefined preprocessor variables.
+
+cat >>confdefs.h <<_ACEOF
+#define PACKAGE_NAME "$PACKAGE_NAME"
+_ACEOF
+
+cat >>confdefs.h <<_ACEOF
+#define PACKAGE_TARNAME "$PACKAGE_TARNAME"
+_ACEOF
+
+cat >>confdefs.h <<_ACEOF
+#define PACKAGE_VERSION "$PACKAGE_VERSION"
+_ACEOF
+
+cat >>confdefs.h <<_ACEOF
+#define PACKAGE_STRING "$PACKAGE_STRING"
+_ACEOF
+
+cat >>confdefs.h <<_ACEOF
+#define PACKAGE_BUGREPORT "$PACKAGE_BUGREPORT"
+_ACEOF
+
+cat >>confdefs.h <<_ACEOF
+#define PACKAGE_URL "$PACKAGE_URL"
+_ACEOF
+
+
+# Let the site file select an alternate cache file if it wants to.
+# Prefer an explicitly selected file to automatically selected ones.
+ac_site_file1=NONE
+ac_site_file2=NONE
+if test -n "$CONFIG_SITE"; then
+  # We do not want a PATH search for config.site.
+  case $CONFIG_SITE in #((
+    -*)  ac_site_file1=./$CONFIG_SITE;;
+    */*) ac_site_file1=$CONFIG_SITE;;
+    *)   ac_site_file1=./$CONFIG_SITE;;
+  esac
+elif test "x$prefix" != xNONE; then
+  ac_site_file1=$prefix/share/config.site
+  ac_site_file2=$prefix/etc/config.site
+else
+  ac_site_file1=$ac_default_prefix/share/config.site
+  ac_site_file2=$ac_default_prefix/etc/config.site
+fi
+for ac_site_file in "$ac_site_file1" "$ac_site_file2"
+do
+  test "x$ac_site_file" = xNONE && continue
+  if test /dev/null != "$ac_site_file" && test -r "$ac_site_file"; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: loading site script $ac_site_file" >&5
+$as_echo "$as_me: loading site script $ac_site_file" >&6;}
+    sed 's/^/| /' "$ac_site_file" >&5
+    . "$ac_site_file" \
+      || { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "failed to load site script $ac_site_file
+See \`config.log' for more details" "$LINENO" 5; }
+  fi
+done
+
+if test -r "$cache_file"; then
+  # Some versions of bash will fail to source /dev/null (special files
+  # actually), so we avoid doing that.  DJGPP emulates it as a regular file.
+  if test /dev/null != "$cache_file" && test -f "$cache_file"; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: loading cache $cache_file" >&5
+$as_echo "$as_me: loading cache $cache_file" >&6;}
+    case $cache_file in
+      [\\/]* | ?:[\\/]* ) . "$cache_file";;
+      *)                      . "./$cache_file";;
+    esac
+  fi
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: creating cache $cache_file" >&5
+$as_echo "$as_me: creating cache $cache_file" >&6;}
+  >$cache_file
+fi
+
+# Check that the precious variables saved in the cache have kept the same
+# value.
+ac_cache_corrupted=false
+for ac_var in $ac_precious_vars; do
+  eval ac_old_set=\$ac_cv_env_${ac_var}_set
+  eval ac_new_set=\$ac_env_${ac_var}_set
+  eval ac_old_val=\$ac_cv_env_${ac_var}_value
+  eval ac_new_val=\$ac_env_${ac_var}_value
+  case $ac_old_set,$ac_new_set in
+    set,)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' was set to \`$ac_old_val' in the previous run" >&5
+$as_echo "$as_me: error: \`$ac_var' was set to \`$ac_old_val' in the previous run" >&2;}
+      ac_cache_corrupted=: ;;
+    ,set)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' was not set in the previous run" >&5
+$as_echo "$as_me: error: \`$ac_var' was not set in the previous run" >&2;}
+      ac_cache_corrupted=: ;;
+    ,);;
+    *)
+      if test "x$ac_old_val" != "x$ac_new_val"; then
+	# differences in whitespace do not lead to failure.
+	ac_old_val_w=`echo x $ac_old_val`
+	ac_new_val_w=`echo x $ac_new_val`
+	if test "$ac_old_val_w" != "$ac_new_val_w"; then
+	  { $as_echo "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' has changed since the previous run:" >&5
+$as_echo "$as_me: error: \`$ac_var' has changed since the previous run:" >&2;}
+	  ac_cache_corrupted=:
+	else
+	  { $as_echo "$as_me:${as_lineno-$LINENO}: warning: ignoring whitespace changes in \`$ac_var' since the previous run:" >&5
+$as_echo "$as_me: warning: ignoring whitespace changes in \`$ac_var' since the previous run:" >&2;}
+	  eval $ac_var=\$ac_old_val
+	fi
+	{ $as_echo "$as_me:${as_lineno-$LINENO}:   former value:  \`$ac_old_val'" >&5
+$as_echo "$as_me:   former value:  \`$ac_old_val'" >&2;}
+	{ $as_echo "$as_me:${as_lineno-$LINENO}:   current value: \`$ac_new_val'" >&5
+$as_echo "$as_me:   current value: \`$ac_new_val'" >&2;}
+      fi;;
+  esac
+  # Pass precious variables to config.status.
+  if test "$ac_new_set" = set; then
+    case $ac_new_val in
+    *\'*) ac_arg=$ac_var=`$as_echo "$ac_new_val" | sed "s/'/'\\\\\\\\''/g"` ;;
+    *) ac_arg=$ac_var=$ac_new_val ;;
+    esac
+    case " $ac_configure_args " in
+      *" '$ac_arg' "*) ;; # Avoid dups.  Use of quotes ensures accuracy.
+      *) as_fn_append ac_configure_args " '$ac_arg'" ;;
+    esac
+  fi
+done
+if $ac_cache_corrupted; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+  { $as_echo "$as_me:${as_lineno-$LINENO}: error: changes in the environment can compromise the build" >&5
+$as_echo "$as_me: error: changes in the environment can compromise the build" >&2;}
+  as_fn_error $? "run \`make distclean' and/or \`rm $cache_file' and start over" "$LINENO" 5
+fi
+## -------------------- ##
+## Main body of script. ##
+## -------------------- ##
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+
+
+# libpng does not follow GNU file name conventions (hence 'foreign')
+# color-tests requires automake 1.11 or later
+# silent-rules requires automake 1.11 or later
+# dist-xz requires automake 1.11 or later
+# 1.12.2 fixes a security issue in 1.11.2 and 1.12.1
+# 1.13 is required for parallel tests
+am__api_version='1.16'
+
+ac_aux_dir=
+for ac_dir in "$srcdir" "$srcdir/.." "$srcdir/../.."; do
+  if test -f "$ac_dir/install-sh"; then
+    ac_aux_dir=$ac_dir
+    ac_install_sh="$ac_aux_dir/install-sh -c"
+    break
+  elif test -f "$ac_dir/install.sh"; then
+    ac_aux_dir=$ac_dir
+    ac_install_sh="$ac_aux_dir/install.sh -c"
+    break
+  elif test -f "$ac_dir/shtool"; then
+    ac_aux_dir=$ac_dir
+    ac_install_sh="$ac_aux_dir/shtool install -c"
+    break
+  fi
+done
+if test -z "$ac_aux_dir"; then
+  as_fn_error $? "cannot find install-sh, install.sh, or shtool in \"$srcdir\" \"$srcdir/..\" \"$srcdir/../..\"" "$LINENO" 5
+fi
+
+# These three variables are undocumented and unsupported,
+# and are intended to be withdrawn in a future Autoconf release.
+# They can cause serious problems if a builder's source tree is in a directory
+# whose full name contains unusual characters.
+ac_config_guess="$SHELL $ac_aux_dir/config.guess"  # Please don't use this var.
+ac_config_sub="$SHELL $ac_aux_dir/config.sub"  # Please don't use this var.
+ac_configure="$SHELL $ac_aux_dir/configure"  # Please don't use this var.
+
+
+# Find a good install program.  We prefer a C program (faster),
+# so one script is as good as another.  But avoid the broken or
+# incompatible versions:
+# SysV /etc/install, /usr/sbin/install
+# SunOS /usr/etc/install
+# IRIX /sbin/install
+# AIX /bin/install
+# AmigaOS /C/install, which installs bootblocks on floppy discs
+# AIX 4 /usr/bin/installbsd, which doesn't work without a -g flag
+# AFS /usr/afsws/bin/install, which mishandles nonexistent args
+# SVR4 /usr/ucb/install, which tries to use the nonexistent group "staff"
+# OS/2's system install, which has a completely different semantic
+# ./install, which can be erroneously created by make from ./install.sh.
+# Reject install programs that cannot install multiple files.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for a BSD-compatible install" >&5
+$as_echo_n "checking for a BSD-compatible install... " >&6; }
+if test -z "$INSTALL"; then
+if ${ac_cv_path_install+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    # Account for people who put trailing slashes in PATH elements.
+case $as_dir/ in #((
+  ./ | .// | /[cC]/* | \
+  /etc/* | /usr/sbin/* | /usr/etc/* | /sbin/* | /usr/afsws/bin/* | \
+  ?:[\\/]os2[\\/]install[\\/]* | ?:[\\/]OS2[\\/]INSTALL[\\/]* | \
+  /usr/ucb/* ) ;;
+  *)
+    # OSF1 and SCO ODT 3.0 have their own names for install.
+    # Don't use installbsd from OSF since it installs stuff as root
+    # by default.
+    for ac_prog in ginstall scoinst install; do
+      for ac_exec_ext in '' $ac_executable_extensions; do
+	if as_fn_executable_p "$as_dir/$ac_prog$ac_exec_ext"; then
+	  if test $ac_prog = install &&
+	    grep dspmsg "$as_dir/$ac_prog$ac_exec_ext" >/dev/null 2>&1; then
+	    # AIX install.  It has an incompatible calling convention.
+	    :
+	  elif test $ac_prog = install &&
+	    grep pwplus "$as_dir/$ac_prog$ac_exec_ext" >/dev/null 2>&1; then
+	    # program-specific install script used by HP pwplus--don't use.
+	    :
+	  else
+	    rm -rf conftest.one conftest.two conftest.dir
+	    echo one > conftest.one
+	    echo two > conftest.two
+	    mkdir conftest.dir
+	    if "$as_dir/$ac_prog$ac_exec_ext" -c conftest.one conftest.two "`pwd`/conftest.dir" &&
+	      test -s conftest.one && test -s conftest.two &&
+	      test -s conftest.dir/conftest.one &&
+	      test -s conftest.dir/conftest.two
+	    then
+	      ac_cv_path_install="$as_dir/$ac_prog$ac_exec_ext -c"
+	      break 3
+	    fi
+	  fi
+	fi
+      done
+    done
+    ;;
+esac
+
+  done
+IFS=$as_save_IFS
+
+rm -rf conftest.one conftest.two conftest.dir
+
+fi
+  if test "${ac_cv_path_install+set}" = set; then
+    INSTALL=$ac_cv_path_install
+  else
+    # As a last resort, use the slow shell script.  Don't cache a
+    # value for INSTALL within a source directory, because that will
+    # break other packages using the cache if that directory is
+    # removed, or if the value is a relative name.
+    INSTALL=$ac_install_sh
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $INSTALL" >&5
+$as_echo "$INSTALL" >&6; }
+
+# Use test -z because SunOS4 sh mishandles braces in ${var-val}.
+# It thinks the first close brace ends the variable substitution.
+test -z "$INSTALL_PROGRAM" && INSTALL_PROGRAM='${INSTALL}'
+
+test -z "$INSTALL_SCRIPT" && INSTALL_SCRIPT='${INSTALL}'
+
+test -z "$INSTALL_DATA" && INSTALL_DATA='${INSTALL} -m 644'
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether build environment is sane" >&5
+$as_echo_n "checking whether build environment is sane... " >&6; }
+# Reject unsafe characters in $srcdir or the absolute working directory
+# name.  Accept space and tab only in the latter.
+am_lf='
+'
+case `pwd` in
+  *[\\\"\#\$\&\'\`$am_lf]*)
+    as_fn_error $? "unsafe absolute working directory name" "$LINENO" 5;;
+esac
+case $srcdir in
+  *[\\\"\#\$\&\'\`$am_lf\ \	]*)
+    as_fn_error $? "unsafe srcdir value: '$srcdir'" "$LINENO" 5;;
+esac
+
+# Do 'set' in a subshell so we don't clobber the current shell's
+# arguments.  Must try -L first in case configure is actually a
+# symlink; some systems play weird games with the mod time of symlinks
+# (eg FreeBSD returns the mod time of the symlink's containing
+# directory).
+if (
+   am_has_slept=no
+   for am_try in 1 2; do
+     echo "timestamp, slept: $am_has_slept" > conftest.file
+     set X `ls -Lt "$srcdir/configure" conftest.file 2> /dev/null`
+     if test "$*" = "X"; then
+	# -L didn't work.
+	set X `ls -t "$srcdir/configure" conftest.file`
+     fi
+     if test "$*" != "X $srcdir/configure conftest.file" \
+	&& test "$*" != "X conftest.file $srcdir/configure"; then
+
+	# If neither matched, then we have a broken ls.  This can happen
+	# if, for instance, CONFIG_SHELL is bash and it inherits a
+	# broken ls alias from the environment.  This has actually
+	# happened.  Such a system could not be considered "sane".
+	as_fn_error $? "ls -t appears to fail.  Make sure there is not a broken
+  alias in your environment" "$LINENO" 5
+     fi
+     if test "$2" = conftest.file || test $am_try -eq 2; then
+       break
+     fi
+     # Just in case.
+     sleep 1
+     am_has_slept=yes
+   done
+   test "$2" = conftest.file
+   )
+then
+   # Ok.
+   :
+else
+   as_fn_error $? "newly created file is older than distributed files!
+Check your system clock" "$LINENO" 5
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+# If we didn't sleep, we still need to ensure time stamps of config.status and
+# generated files are strictly newer.
+am_sleep_pid=
+if grep 'slept: no' conftest.file >/dev/null 2>&1; then
+  ( sleep 1 ) &
+  am_sleep_pid=$!
+fi
+
+rm -f conftest.file
+
+test "$program_prefix" != NONE &&
+  program_transform_name="s&^&$program_prefix&;$program_transform_name"
+# Use a double $ so make ignores it.
+test "$program_suffix" != NONE &&
+  program_transform_name="s&\$&$program_suffix&;$program_transform_name"
+# Double any \ or $.
+# By default was `s,x,x', remove it if useless.
+ac_script='s/[\\$]/&&/g;s/;s,x,x,$//'
+program_transform_name=`$as_echo "$program_transform_name" | sed "$ac_script"`
+
+# Expand $ac_aux_dir to an absolute path.
+am_aux_dir=`cd "$ac_aux_dir" && pwd`
+
+if test x"${MISSING+set}" != xset; then
+  case $am_aux_dir in
+  *\ * | *\	*)
+    MISSING="\${SHELL} \"$am_aux_dir/missing\"" ;;
+  *)
+    MISSING="\${SHELL} $am_aux_dir/missing" ;;
+  esac
+fi
+# Use eval to expand $SHELL
+if eval "$MISSING --is-lightweight"; then
+  am_missing_run="$MISSING "
+else
+  am_missing_run=
+  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: 'missing' script is too old or missing" >&5
+$as_echo "$as_me: WARNING: 'missing' script is too old or missing" >&2;}
+fi
+
+if test x"${install_sh+set}" != xset; then
+  case $am_aux_dir in
+  *\ * | *\	*)
+    install_sh="\${SHELL} '$am_aux_dir/install-sh'" ;;
+  *)
+    install_sh="\${SHELL} $am_aux_dir/install-sh"
+  esac
+fi
+
+# Installed binaries are usually stripped using 'strip' when the user
+# run "make install-strip".  However 'strip' might not be the right
+# tool to use in cross-compilation environments, therefore Automake
+# will honor the 'STRIP' environment variable to overrule this program.
+if test "$cross_compiling" != no; then
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}strip", so it can be a program name with args.
+set dummy ${ac_tool_prefix}strip; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_STRIP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$STRIP"; then
+  ac_cv_prog_STRIP="$STRIP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_STRIP="${ac_tool_prefix}strip"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+STRIP=$ac_cv_prog_STRIP
+if test -n "$STRIP"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $STRIP" >&5
+$as_echo "$STRIP" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_STRIP"; then
+  ac_ct_STRIP=$STRIP
+  # Extract the first word of "strip", so it can be a program name with args.
+set dummy strip; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_STRIP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_STRIP"; then
+  ac_cv_prog_ac_ct_STRIP="$ac_ct_STRIP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_STRIP="strip"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_STRIP=$ac_cv_prog_ac_ct_STRIP
+if test -n "$ac_ct_STRIP"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_STRIP" >&5
+$as_echo "$ac_ct_STRIP" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_STRIP" = x; then
+    STRIP=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    STRIP=$ac_ct_STRIP
+  fi
+else
+  STRIP="$ac_cv_prog_STRIP"
+fi
+
+fi
+INSTALL_STRIP_PROGRAM="\$(install_sh) -c -s"
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for a thread-safe mkdir -p" >&5
+$as_echo_n "checking for a thread-safe mkdir -p... " >&6; }
+if test -z "$MKDIR_P"; then
+  if ${ac_cv_path_mkdir+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/opt/sfw/bin
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in mkdir gmkdir; do
+	 for ac_exec_ext in '' $ac_executable_extensions; do
+	   as_fn_executable_p "$as_dir/$ac_prog$ac_exec_ext" || continue
+	   case `"$as_dir/$ac_prog$ac_exec_ext" --version 2>&1` in #(
+	     'mkdir (GNU coreutils) '* | \
+	     'mkdir (coreutils) '* | \
+	     'mkdir (fileutils) '4.1*)
+	       ac_cv_path_mkdir=$as_dir/$ac_prog$ac_exec_ext
+	       break 3;;
+	   esac
+	 done
+       done
+  done
+IFS=$as_save_IFS
+
+fi
+
+  test -d ./--version && rmdir ./--version
+  if test "${ac_cv_path_mkdir+set}" = set; then
+    MKDIR_P="$ac_cv_path_mkdir -p"
+  else
+    # As a last resort, use the slow shell script.  Don't cache a
+    # value for MKDIR_P within a source directory, because that will
+    # break other packages using the cache if that directory is
+    # removed, or if the value is a relative name.
+    MKDIR_P="$ac_install_sh -d"
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $MKDIR_P" >&5
+$as_echo "$MKDIR_P" >&6; }
+
+for ac_prog in gawk mawk nawk awk
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_AWK+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$AWK"; then
+  ac_cv_prog_AWK="$AWK" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AWK="$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+AWK=$ac_cv_prog_AWK
+if test -n "$AWK"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $AWK" >&5
+$as_echo "$AWK" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  test -n "$AWK" && break
+done
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${MAKE-make} sets \$(MAKE)" >&5
+$as_echo_n "checking whether ${MAKE-make} sets \$(MAKE)... " >&6; }
+set x ${MAKE-make}
+ac_make=`$as_echo "$2" | sed 's/+/p/g; s/[^a-zA-Z0-9_]/_/g'`
+if eval \${ac_cv_prog_make_${ac_make}_set+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat >conftest.make <<\_ACEOF
+SHELL = /bin/sh
+all:
+	@echo '@@@%%%=$(MAKE)=@@@%%%'
+_ACEOF
+# GNU make sometimes prints "make[1]: Entering ...", which would confuse us.
+case `${MAKE-make} -f conftest.make 2>/dev/null` in
+  *@@@%%%=?*=@@@%%%*)
+    eval ac_cv_prog_make_${ac_make}_set=yes;;
+  *)
+    eval ac_cv_prog_make_${ac_make}_set=no;;
+esac
+rm -f conftest.make
+fi
+if eval test \$ac_cv_prog_make_${ac_make}_set = yes; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+  SET_MAKE=
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+  SET_MAKE="MAKE=${MAKE-make}"
+fi
+
+rm -rf .tst 2>/dev/null
+mkdir .tst 2>/dev/null
+if test -d .tst; then
+  am__leading_dot=.
+else
+  am__leading_dot=_
+fi
+rmdir .tst 2>/dev/null
+
+# Check whether --enable-silent-rules was given.
+if test "${enable_silent_rules+set}" = set; then :
+  enableval=$enable_silent_rules;
+fi
+
+case $enable_silent_rules in # (((
+  yes) AM_DEFAULT_VERBOSITY=0;;
+   no) AM_DEFAULT_VERBOSITY=1;;
+    *) AM_DEFAULT_VERBOSITY=1;;
+esac
+am_make=${MAKE-make}
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $am_make supports nested variables" >&5
+$as_echo_n "checking whether $am_make supports nested variables... " >&6; }
+if ${am_cv_make_support_nested_variables+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if $as_echo 'TRUE=$(BAR$(V))
+BAR0=false
+BAR1=true
+V=1
+am__doit:
+	@$(TRUE)
+.PHONY: am__doit' | $am_make -f - >/dev/null 2>&1; then
+  am_cv_make_support_nested_variables=yes
+else
+  am_cv_make_support_nested_variables=no
+fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $am_cv_make_support_nested_variables" >&5
+$as_echo "$am_cv_make_support_nested_variables" >&6; }
+if test $am_cv_make_support_nested_variables = yes; then
+    AM_V='$(V)'
+  AM_DEFAULT_V='$(AM_DEFAULT_VERBOSITY)'
+else
+  AM_V=$AM_DEFAULT_VERBOSITY
+  AM_DEFAULT_V=$AM_DEFAULT_VERBOSITY
+fi
+AM_BACKSLASH='\'
+
+if test "`cd $srcdir && pwd`" != "`pwd`"; then
+  # Use -I$(srcdir) only when $(srcdir) != ., so that make's output
+  # is not polluted with repeated "-I."
+  am__isrc=' -I$(srcdir)'
+  # test to see if srcdir already configured
+  if test -f $srcdir/config.status; then
+    as_fn_error $? "source directory already configured; run \"make distclean\" there first" "$LINENO" 5
+  fi
+fi
+
+# test whether we have cygpath
+if test -z "$CYGPATH_W"; then
+  if (cygpath --version) >/dev/null 2>/dev/null; then
+    CYGPATH_W='cygpath -w'
+  else
+    CYGPATH_W=echo
+  fi
+fi
+
+
+# Define the identity of the package.
+ PACKAGE='libpng'
+ VERSION='1.6.37'
+
+
+cat >>confdefs.h <<_ACEOF
+#define PACKAGE "$PACKAGE"
+_ACEOF
+
+
+cat >>confdefs.h <<_ACEOF
+#define VERSION "$VERSION"
+_ACEOF
+
+# Some tools Automake needs.
+
+ACLOCAL=${ACLOCAL-"${am_missing_run}aclocal-${am__api_version}"}
+
+
+AUTOCONF=${AUTOCONF-"${am_missing_run}autoconf"}
+
+
+AUTOMAKE=${AUTOMAKE-"${am_missing_run}automake-${am__api_version}"}
+
+
+AUTOHEADER=${AUTOHEADER-"${am_missing_run}autoheader"}
+
+
+MAKEINFO=${MAKEINFO-"${am_missing_run}makeinfo"}
+
+# For better backward compatibility.  To be removed once Automake 1.9.x
+# dies out for good.  For more background, see:
+# <https://lists.gnu.org/archive/html/automake/2012-07/msg00001.html>
+# <https://lists.gnu.org/archive/html/automake/2012-07/msg00014.html>
+mkdir_p='$(MKDIR_P)'
+
+# We need awk for the "check" target (and possibly the TAP driver).  The
+# system "awk" is bad on some platforms.
+# Always define AMTAR for backward compatibility.  Yes, it's still used
+# in the wild :-(  We should find a proper way to deprecate it ...
+AMTAR='$${TAR-tar}'
+
+
+# We'll loop over all known methods to create a tar archive until one works.
+_am_tools='gnutar  pax cpio none'
+
+am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'
+
+
+
+
+
+
+# POSIX will say in a future version that running "rm -f" with no argument
+# is OK; and we want to be able to make that assumption in our Makefile
+# recipes.  So use an aggressive probe to check that the usage we want is
+# actually supported "in the wild" to an acceptable degree.
+# See automake bug#10828.
+# To make any issue more visible, cause the running configure to be aborted
+# by default if the 'rm' program in use doesn't match our expectations; the
+# user can still override this though.
+if rm -f && rm -fr && rm -rf; then : OK; else
+  cat >&2 <<'END'
+Oops!
+
+Your 'rm' program seems unable to run without file operands specified
+on the command line, even when the '-f' option is present.  This is contrary
+to the behaviour of most rm programs out there, and not conforming with
+the upcoming POSIX standard: <http://austingroupbugs.net/view.php?id=542>
+
+Please tell bug-automake@gnu.org about your system, including the value
+of your $PATH and any error possibly output before this message.  This
+can help us improve future automake versions.
+
+END
+  if test x"$ACCEPT_INFERIOR_RM_PROGRAM" = x"yes"; then
+    echo 'Configuration will proceed anyway, since you have set the' >&2
+    echo 'ACCEPT_INFERIOR_RM_PROGRAM variable to "yes"' >&2
+    echo >&2
+  else
+    cat >&2 <<'END'
+Aborting the configuration process, to ensure you take notice of the issue.
+
+You can download and install GNU coreutils to get an 'rm' implementation
+that behaves properly: <https://www.gnu.org/software/coreutils/>.
+
+If you want to complete the configuration process using your problematic
+'rm' anyway, export the environment variable ACCEPT_INFERIOR_RM_PROGRAM
+to "yes", and re-run configure.
+
+END
+    as_fn_error $? "Your 'rm' program is bad, sorry." "$LINENO" 5
+  fi
+fi
+
+# The following line causes --disable-maintainer-mode to be the default to
+# configure. This is necessary because libpng distributions cannot rely on the
+# time stamps of the autotools generated files being correct
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to enable maintainer-specific portions of Makefiles" >&5
+$as_echo_n "checking whether to enable maintainer-specific portions of Makefiles... " >&6; }
+    # Check whether --enable-maintainer-mode was given.
+if test "${enable_maintainer_mode+set}" = set; then :
+  enableval=$enable_maintainer_mode; USE_MAINTAINER_MODE=$enableval
+else
+  USE_MAINTAINER_MODE=no
+fi
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $USE_MAINTAINER_MODE" >&5
+$as_echo "$USE_MAINTAINER_MODE" >&6; }
+   if test $USE_MAINTAINER_MODE = yes; then
+  MAINTAINER_MODE_TRUE=
+  MAINTAINER_MODE_FALSE='#'
+else
+  MAINTAINER_MODE_TRUE='#'
+  MAINTAINER_MODE_FALSE=
+fi
+
+  MAINT=$MAINTAINER_MODE_TRUE
+
+
+
+
+PNGLIB_VERSION=1.6.37
+PNGLIB_MAJOR=1
+PNGLIB_MINOR=6
+PNGLIB_RELEASE=37
+
+
+
+ac_config_headers="$ac_config_headers config.h"
+
+
+# Checks for programs.
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}gcc", so it can be a program name with args.
+set dummy ${ac_tool_prefix}gcc; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_CC+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="${ac_tool_prefix}gcc"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+$as_echo "$CC" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_CC"; then
+  ac_ct_CC=$CC
+  # Extract the first word of "gcc", so it can be a program name with args.
+set dummy gcc; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_CC+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_CC"; then
+  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_CC="gcc"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_CC=$ac_cv_prog_ac_ct_CC
+if test -n "$ac_ct_CC"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
+$as_echo "$ac_ct_CC" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_CC" = x; then
+    CC=""
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    CC=$ac_ct_CC
+  fi
+else
+  CC="$ac_cv_prog_CC"
+fi
+
+if test -z "$CC"; then
+          if test -n "$ac_tool_prefix"; then
+    # Extract the first word of "${ac_tool_prefix}cc", so it can be a program name with args.
+set dummy ${ac_tool_prefix}cc; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_CC+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="${ac_tool_prefix}cc"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+$as_echo "$CC" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  fi
+fi
+if test -z "$CC"; then
+  # Extract the first word of "cc", so it can be a program name with args.
+set dummy cc; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_CC+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+  ac_prog_rejected=no
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    if test "$as_dir/$ac_word$ac_exec_ext" = "/usr/ucb/cc"; then
+       ac_prog_rejected=yes
+       continue
+     fi
+    ac_cv_prog_CC="cc"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+if test $ac_prog_rejected = yes; then
+  # We found a bogon in the path, so make sure we never use it.
+  set dummy $ac_cv_prog_CC
+  shift
+  if test $# != 0; then
+    # We chose a different compiler from the bogus one.
+    # However, it has the same basename, so the bogon will be chosen
+    # first if we set CC to just the basename; use the full file name.
+    shift
+    ac_cv_prog_CC="$as_dir/$ac_word${1+' '}$@"
+  fi
+fi
+fi
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+$as_echo "$CC" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$CC"; then
+  if test -n "$ac_tool_prefix"; then
+  for ac_prog in cl.exe
+  do
+    # Extract the first word of "$ac_tool_prefix$ac_prog", so it can be a program name with args.
+set dummy $ac_tool_prefix$ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_CC+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="$ac_tool_prefix$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+$as_echo "$CC" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+    test -n "$CC" && break
+  done
+fi
+if test -z "$CC"; then
+  ac_ct_CC=$CC
+  for ac_prog in cl.exe
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_CC+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_CC"; then
+  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_CC="$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_CC=$ac_cv_prog_ac_ct_CC
+if test -n "$ac_ct_CC"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
+$as_echo "$ac_ct_CC" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  test -n "$ac_ct_CC" && break
+done
+
+  if test "x$ac_ct_CC" = x; then
+    CC=""
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    CC=$ac_ct_CC
+  fi
+fi
+
+fi
+
+
+test -z "$CC" && { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "no acceptable C compiler found in \$PATH
+See \`config.log' for more details" "$LINENO" 5; }
+
+# Provide some information about the compiler.
+$as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler version" >&5
+set X $ac_compile
+ac_compiler=$2
+for ac_option in --version -v -V -qversion; do
+  { { ac_try="$ac_compiler $ac_option >&5"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_compiler $ac_option >&5") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    sed '10a\
+... rest of stderr output deleted ...
+         10q' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+  fi
+  rm -f conftest.er1 conftest.err
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+done
+
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+ac_clean_files_save=$ac_clean_files
+ac_clean_files="$ac_clean_files a.out a.out.dSYM a.exe b.out"
+# Try to create an executable without -o first, disregard a.out.
+# It will help us diagnose broken compilers, and finding out an intuition
+# of exeext.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the C compiler works" >&5
+$as_echo_n "checking whether the C compiler works... " >&6; }
+ac_link_default=`$as_echo "$ac_link" | sed 's/ -o *conftest[^ ]*//'`
+
+# The possible output files:
+ac_files="a.out conftest.exe conftest a.exe a_out.exe b.out conftest.*"
+
+ac_rmfiles=
+for ac_file in $ac_files
+do
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM | *.o | *.obj ) ;;
+    * ) ac_rmfiles="$ac_rmfiles $ac_file";;
+  esac
+done
+rm -f $ac_rmfiles
+
+if { { ac_try="$ac_link_default"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_link_default") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then :
+  # Autoconf-2.13 could set the ac_cv_exeext variable to `no'.
+# So ignore a value of `no', otherwise this would lead to `EXEEXT = no'
+# in a Makefile.  We should not override ac_cv_exeext if it was cached,
+# so that the user can short-circuit this test for compilers unknown to
+# Autoconf.
+for ac_file in $ac_files ''
+do
+  test -f "$ac_file" || continue
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM | *.o | *.obj )
+	;;
+    [ab].out )
+	# We found the default executable, but exeext='' is most
+	# certainly right.
+	break;;
+    *.* )
+	if test "${ac_cv_exeext+set}" = set && test "$ac_cv_exeext" != no;
+	then :; else
+	   ac_cv_exeext=`expr "$ac_file" : '[^.]*\(\..*\)'`
+	fi
+	# We set ac_cv_exeext here because the later test for it is not
+	# safe: cross compilers may not add the suffix if given an `-o'
+	# argument, so we may need to know it at that point already.
+	# Even if this section looks crufty: it has the advantage of
+	# actually working.
+	break;;
+    * )
+	break;;
+  esac
+done
+test "$ac_cv_exeext" = no && ac_cv_exeext=
+
+else
+  ac_file=''
+fi
+if test -z "$ac_file"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+$as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+{ { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error 77 "C compiler cannot create executables
+See \`config.log' for more details" "$LINENO" 5; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler default output file name" >&5
+$as_echo_n "checking for C compiler default output file name... " >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_file" >&5
+$as_echo "$ac_file" >&6; }
+ac_exeext=$ac_cv_exeext
+
+rm -f -r a.out a.out.dSYM a.exe conftest$ac_cv_exeext b.out
+ac_clean_files=$ac_clean_files_save
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for suffix of executables" >&5
+$as_echo_n "checking for suffix of executables... " >&6; }
+if { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then :
+  # If both `conftest.exe' and `conftest' are `present' (well, observable)
+# catch `conftest.exe'.  For instance with Cygwin, `ls conftest' will
+# work properly (i.e., refer to `conftest.exe'), while it won't with
+# `rm'.
+for ac_file in conftest.exe conftest conftest.*; do
+  test -f "$ac_file" || continue
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM | *.o | *.obj ) ;;
+    *.* ) ac_cv_exeext=`expr "$ac_file" : '[^.]*\(\..*\)'`
+	  break;;
+    * ) break;;
+  esac
+done
+else
+  { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "cannot compute suffix of executables: cannot compile and link
+See \`config.log' for more details" "$LINENO" 5; }
+fi
+rm -f conftest conftest$ac_cv_exeext
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_exeext" >&5
+$as_echo "$ac_cv_exeext" >&6; }
+
+rm -f conftest.$ac_ext
+EXEEXT=$ac_cv_exeext
+ac_exeext=$EXEEXT
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdio.h>
+int
+main ()
+{
+FILE *f = fopen ("conftest.out", "w");
+ return ferror (f) || fclose (f) != 0;
+
+  ;
+  return 0;
+}
+_ACEOF
+ac_clean_files="$ac_clean_files conftest.out"
+# Check that the compiler produces executables we can run.  If not, either
+# the compiler is broken, or we cross compile.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether we are cross compiling" >&5
+$as_echo_n "checking whether we are cross compiling... " >&6; }
+if test "$cross_compiling" != yes; then
+  { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+  if { ac_try='./conftest$ac_cv_exeext'
+  { { case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }; then
+    cross_compiling=no
+  else
+    if test "$cross_compiling" = maybe; then
+	cross_compiling=yes
+    else
+	{ { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "cannot run C compiled programs.
+If you meant to cross compile, use \`--host'.
+See \`config.log' for more details" "$LINENO" 5; }
+    fi
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $cross_compiling" >&5
+$as_echo "$cross_compiling" >&6; }
+
+rm -f conftest.$ac_ext conftest$ac_cv_exeext conftest.out
+ac_clean_files=$ac_clean_files_save
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for suffix of object files" >&5
+$as_echo_n "checking for suffix of object files... " >&6; }
+if ${ac_cv_objext+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.o conftest.obj
+if { { ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_compile") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then :
+  for ac_file in conftest.o conftest.obj conftest.*; do
+  test -f "$ac_file" || continue;
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM ) ;;
+    *) ac_cv_objext=`expr "$ac_file" : '.*\.\(.*\)'`
+       break;;
+  esac
+done
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+{ { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "cannot compute suffix of object files: cannot compile
+See \`config.log' for more details" "$LINENO" 5; }
+fi
+rm -f conftest.$ac_cv_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_objext" >&5
+$as_echo "$ac_cv_objext" >&6; }
+OBJEXT=$ac_cv_objext
+ac_objext=$OBJEXT
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether we are using the GNU C compiler" >&5
+$as_echo_n "checking whether we are using the GNU C compiler... " >&6; }
+if ${ac_cv_c_compiler_gnu+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+#ifndef __GNUC__
+       choke me
+#endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_compiler_gnu=yes
+else
+  ac_compiler_gnu=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_cv_c_compiler_gnu=$ac_compiler_gnu
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_c_compiler_gnu" >&5
+$as_echo "$ac_cv_c_compiler_gnu" >&6; }
+if test $ac_compiler_gnu = yes; then
+  GCC=yes
+else
+  GCC=
+fi
+ac_test_CFLAGS=${CFLAGS+set}
+ac_save_CFLAGS=$CFLAGS
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC accepts -g" >&5
+$as_echo_n "checking whether $CC accepts -g... " >&6; }
+if ${ac_cv_prog_cc_g+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_save_c_werror_flag=$ac_c_werror_flag
+   ac_c_werror_flag=yes
+   ac_cv_prog_cc_g=no
+   CFLAGS="-g"
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_prog_cc_g=yes
+else
+  CFLAGS=""
+      cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+else
+  ac_c_werror_flag=$ac_save_c_werror_flag
+	 CFLAGS="-g"
+	 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_prog_cc_g=yes
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+   ac_c_werror_flag=$ac_save_c_werror_flag
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_g" >&5
+$as_echo "$ac_cv_prog_cc_g" >&6; }
+if test "$ac_test_CFLAGS" = set; then
+  CFLAGS=$ac_save_CFLAGS
+elif test $ac_cv_prog_cc_g = yes; then
+  if test "$GCC" = yes; then
+    CFLAGS="-g -O2"
+  else
+    CFLAGS="-g"
+  fi
+else
+  if test "$GCC" = yes; then
+    CFLAGS="-O2"
+  else
+    CFLAGS=
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $CC option to accept ISO C89" >&5
+$as_echo_n "checking for $CC option to accept ISO C89... " >&6; }
+if ${ac_cv_prog_cc_c89+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_prog_cc_c89=no
+ac_save_CC=$CC
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdarg.h>
+#include <stdio.h>
+struct stat;
+/* Most of the following tests are stolen from RCS 5.7's src/conf.sh.  */
+struct buf { int x; };
+FILE * (*rcsopen) (struct buf *, struct stat *, int);
+static char *e (p, i)
+     char **p;
+     int i;
+{
+  return p[i];
+}
+static char *f (char * (*g) (char **, int), char **p, ...)
+{
+  char *s;
+  va_list v;
+  va_start (v,p);
+  s = g (p, va_arg (v,int));
+  va_end (v);
+  return s;
+}
+
+/* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
+   function prototypes and stuff, but not '\xHH' hex character constants.
+   These don't provoke an error unfortunately, instead are silently treated
+   as 'x'.  The following induces an error, until -std is added to get
+   proper ANSI mode.  Curiously '\x00'!='x' always comes out true, for an
+   array size at least.  It's necessary to write '\x00'==0 to get something
+   that's true only with -std.  */
+int osf4_cc_array ['\x00' == 0 ? 1 : -1];
+
+/* IBM C 6 for AIX is almost-ANSI by default, but it replaces macro parameters
+   inside strings and character constants.  */
+#define FOO(x) 'x'
+int xlc6_cc_array[FOO(a) == 'x' ? 1 : -1];
+
+int test (int i, double x);
+struct s1 {int (*f) (int a);};
+struct s2 {int (*f) (double a);};
+int pairnames (int, char **, FILE *(*)(struct buf *, struct stat *, int), int, int);
+int argc;
+char **argv;
+int
+main ()
+{
+return f (e, argv, 0) != argv[0]  ||  f (e, argv, 1) != argv[1];
+  ;
+  return 0;
+}
+_ACEOF
+for ac_arg in '' -qlanglvl=extc89 -qlanglvl=ansi -std \
+	-Ae "-Aa -D_HPUX_SOURCE" "-Xc -D__EXTENSIONS__"
+do
+  CC="$ac_save_CC $ac_arg"
+  if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_prog_cc_c89=$ac_arg
+fi
+rm -f core conftest.err conftest.$ac_objext
+  test "x$ac_cv_prog_cc_c89" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CC=$ac_save_CC
+
+fi
+# AC_CACHE_VAL
+case "x$ac_cv_prog_cc_c89" in
+  x)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+$as_echo "none needed" >&6; } ;;
+  xno)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+$as_echo "unsupported" >&6; } ;;
+  *)
+    CC="$CC $ac_cv_prog_cc_c89"
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c89" >&5
+$as_echo "$ac_cv_prog_cc_c89" >&6; } ;;
+esac
+if test "x$ac_cv_prog_cc_c89" != xno; then :
+
+fi
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC understands -c and -o together" >&5
+$as_echo_n "checking whether $CC understands -c and -o together... " >&6; }
+if ${am_cv_prog_cc_c_o+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+  # Make sure it works both with $CC and with simple cc.
+  # Following AC_PROG_CC_C_O, we do the test twice because some
+  # compilers refuse to overwrite an existing .o file with -o,
+  # though they will create one.
+  am_cv_prog_cc_c_o=yes
+  for am_i in 1 2; do
+    if { echo "$as_me:$LINENO: $CC -c conftest.$ac_ext -o conftest2.$ac_objext" >&5
+   ($CC -c conftest.$ac_ext -o conftest2.$ac_objext) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); } \
+         && test -f conftest2.$ac_objext; then
+      : OK
+    else
+      am_cv_prog_cc_c_o=no
+      break
+    fi
+  done
+  rm -f core conftest*
+  unset am_i
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $am_cv_prog_cc_c_o" >&5
+$as_echo "$am_cv_prog_cc_c_o" >&6; }
+if test "$am_cv_prog_cc_c_o" != yes; then
+   # Losing compiler, so override with the script.
+   # FIXME: It is wrong to rewrite CC.
+   # But if we don't then we get into trouble of one sort or another.
+   # A longer-term fix would be to have automake use am__CC in this case,
+   # and then we could set am__CC="\$(top_srcdir)/compile \$(CC)"
+   CC="$am_aux_dir/compile $CC"
+fi
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+DEPDIR="${am__leading_dot}deps"
+
+ac_config_commands="$ac_config_commands depfiles"
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${MAKE-make} supports the include directive" >&5
+$as_echo_n "checking whether ${MAKE-make} supports the include directive... " >&6; }
+cat > confinc.mk << 'END'
+am__doit:
+	@echo this is the am__doit target >confinc.out
+.PHONY: am__doit
+END
+am__include="#"
+am__quote=
+# BSD make does it like this.
+echo '.include "confinc.mk" # ignored' > confmf.BSD
+# Other make implementations (GNU, Solaris 10, AIX) do it like this.
+echo 'include confinc.mk # ignored' > confmf.GNU
+_am_result=no
+for s in GNU BSD; do
+  { echo "$as_me:$LINENO: ${MAKE-make} -f confmf.$s && cat confinc.out" >&5
+   (${MAKE-make} -f confmf.$s && cat confinc.out) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); }
+  case $?:`cat confinc.out 2>/dev/null` in #(
+  '0:this is the am__doit target') :
+    case $s in #(
+  BSD) :
+    am__include='.include' am__quote='"' ;; #(
+  *) :
+    am__include='include' am__quote='' ;;
+esac ;; #(
+  *) :
+     ;;
+esac
+  if test "$am__include" != "#"; then
+    _am_result="yes ($s style)"
+    break
+  fi
+done
+rm -f confinc.* confmf.*
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: ${_am_result}" >&5
+$as_echo "${_am_result}" >&6; }
+
+# Check whether --enable-dependency-tracking was given.
+if test "${enable_dependency_tracking+set}" = set; then :
+  enableval=$enable_dependency_tracking;
+fi
+
+if test "x$enable_dependency_tracking" != xno; then
+  am_depcomp="$ac_aux_dir/depcomp"
+  AMDEPBACKSLASH='\'
+  am__nodep='_no'
+fi
+ if test "x$enable_dependency_tracking" != xno; then
+  AMDEP_TRUE=
+  AMDEP_FALSE='#'
+else
+  AMDEP_TRUE='#'
+  AMDEP_FALSE=
+fi
+
+
+
+depcc="$CC"   am_compiler_list=
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking dependency style of $depcc" >&5
+$as_echo_n "checking dependency style of $depcc... " >&6; }
+if ${am_cv_CC_dependencies_compiler_type+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -z "$AMDEP_TRUE" && test -f "$am_depcomp"; then
+  # We make a subdir and do the tests there.  Otherwise we can end up
+  # making bogus files that we don't know about and never remove.  For
+  # instance it was reported that on HP-UX the gcc test will end up
+  # making a dummy file named 'D' -- because '-MD' means "put the output
+  # in D".
+  rm -rf conftest.dir
+  mkdir conftest.dir
+  # Copy depcomp to subdir because otherwise we won't find it if we're
+  # using a relative directory.
+  cp "$am_depcomp" conftest.dir
+  cd conftest.dir
+  # We will build objects and dependencies in a subdirectory because
+  # it helps to detect inapplicable dependency modes.  For instance
+  # both Tru64's cc and ICC support -MD to output dependencies as a
+  # side effect of compilation, but ICC will put the dependencies in
+  # the current directory while Tru64 will put them in the object
+  # directory.
+  mkdir sub
+
+  am_cv_CC_dependencies_compiler_type=none
+  if test "$am_compiler_list" = ""; then
+     am_compiler_list=`sed -n 's/^#*\([a-zA-Z0-9]*\))$/\1/p' < ./depcomp`
+  fi
+  am__universal=false
+  case " $depcc " in #(
+     *\ -arch\ *\ -arch\ *) am__universal=true ;;
+     esac
+
+  for depmode in $am_compiler_list; do
+    # Setup a source with many dependencies, because some compilers
+    # like to wrap large dependency lists on column 80 (with \), and
+    # we should not choose a depcomp mode which is confused by this.
+    #
+    # We need to recreate these files for each test, as the compiler may
+    # overwrite some of them when testing with obscure command lines.
+    # This happens at least with the AIX C compiler.
+    : > sub/conftest.c
+    for i in 1 2 3 4 5 6; do
+      echo '#include "conftst'$i'.h"' >> sub/conftest.c
+      # Using ": > sub/conftst$i.h" creates only sub/conftst1.h with
+      # Solaris 10 /bin/sh.
+      echo '/* dummy */' > sub/conftst$i.h
+    done
+    echo "${am__include} ${am__quote}sub/conftest.Po${am__quote}" > confmf
+
+    # We check with '-c' and '-o' for the sake of the "dashmstdout"
+    # mode.  It turns out that the SunPro C++ compiler does not properly
+    # handle '-M -o', and we need to detect this.  Also, some Intel
+    # versions had trouble with output in subdirs.
+    am__obj=sub/conftest.${OBJEXT-o}
+    am__minus_obj="-o $am__obj"
+    case $depmode in
+    gcc)
+      # This depmode causes a compiler race in universal mode.
+      test "$am__universal" = false || continue
+      ;;
+    nosideeffect)
+      # After this tag, mechanisms are not by side-effect, so they'll
+      # only be used when explicitly requested.
+      if test "x$enable_dependency_tracking" = xyes; then
+	continue
+      else
+	break
+      fi
+      ;;
+    msvc7 | msvc7msys | msvisualcpp | msvcmsys)
+      # This compiler won't grok '-c -o', but also, the minuso test has
+      # not run yet.  These depmodes are late enough in the game, and
+      # so weak that their functioning should not be impacted.
+      am__obj=conftest.${OBJEXT-o}
+      am__minus_obj=
+      ;;
+    none) break ;;
+    esac
+    if depmode=$depmode \
+       source=sub/conftest.c object=$am__obj \
+       depfile=sub/conftest.Po tmpdepfile=sub/conftest.TPo \
+       $SHELL ./depcomp $depcc -c $am__minus_obj sub/conftest.c \
+         >/dev/null 2>conftest.err &&
+       grep sub/conftst1.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep sub/conftst6.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep $am__obj sub/conftest.Po > /dev/null 2>&1 &&
+       ${MAKE-make} -s -f confmf > /dev/null 2>&1; then
+      # icc doesn't choke on unknown options, it will just issue warnings
+      # or remarks (even with -Werror).  So we grep stderr for any message
+      # that says an option was ignored or not supported.
+      # When given -MP, icc 7.0 and 7.1 complain thusly:
+      #   icc: Command line warning: ignoring option '-M'; no argument required
+      # The diagnosis changed in icc 8.0:
+      #   icc: Command line remark: option '-MP' not supported
+      if (grep 'ignoring option' conftest.err ||
+          grep 'not supported' conftest.err) >/dev/null 2>&1; then :; else
+        am_cv_CC_dependencies_compiler_type=$depmode
+        break
+      fi
+    fi
+  done
+
+  cd ..
+  rm -rf conftest.dir
+else
+  am_cv_CC_dependencies_compiler_type=none
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $am_cv_CC_dependencies_compiler_type" >&5
+$as_echo "$am_cv_CC_dependencies_compiler_type" >&6; }
+CCDEPMODE=depmode=$am_cv_CC_dependencies_compiler_type
+
+ if
+  test "x$enable_dependency_tracking" != xno \
+  && test "$am_cv_CC_dependencies_compiler_type" = gcc3; then
+  am__fastdepCC_TRUE=
+  am__fastdepCC_FALSE='#'
+else
+  am__fastdepCC_TRUE='#'
+  am__fastdepCC_FALSE=
+fi
+
+
+# By default we simply use the C compiler to build assembly code.
+
+test "${CCAS+set}" = set || CCAS=$CC
+test "${CCASFLAGS+set}" = set || CCASFLAGS=$CFLAGS
+
+
+
+depcc="$CCAS"   am_compiler_list=
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking dependency style of $depcc" >&5
+$as_echo_n "checking dependency style of $depcc... " >&6; }
+if ${am_cv_CCAS_dependencies_compiler_type+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -z "$AMDEP_TRUE" && test -f "$am_depcomp"; then
+  # We make a subdir and do the tests there.  Otherwise we can end up
+  # making bogus files that we don't know about and never remove.  For
+  # instance it was reported that on HP-UX the gcc test will end up
+  # making a dummy file named 'D' -- because '-MD' means "put the output
+  # in D".
+  rm -rf conftest.dir
+  mkdir conftest.dir
+  # Copy depcomp to subdir because otherwise we won't find it if we're
+  # using a relative directory.
+  cp "$am_depcomp" conftest.dir
+  cd conftest.dir
+  # We will build objects and dependencies in a subdirectory because
+  # it helps to detect inapplicable dependency modes.  For instance
+  # both Tru64's cc and ICC support -MD to output dependencies as a
+  # side effect of compilation, but ICC will put the dependencies in
+  # the current directory while Tru64 will put them in the object
+  # directory.
+  mkdir sub
+
+  am_cv_CCAS_dependencies_compiler_type=none
+  if test "$am_compiler_list" = ""; then
+     am_compiler_list=`sed -n 's/^#*\([a-zA-Z0-9]*\))$/\1/p' < ./depcomp`
+  fi
+  am__universal=false
+
+
+  for depmode in $am_compiler_list; do
+    # Setup a source with many dependencies, because some compilers
+    # like to wrap large dependency lists on column 80 (with \), and
+    # we should not choose a depcomp mode which is confused by this.
+    #
+    # We need to recreate these files for each test, as the compiler may
+    # overwrite some of them when testing with obscure command lines.
+    # This happens at least with the AIX C compiler.
+    : > sub/conftest.c
+    for i in 1 2 3 4 5 6; do
+      echo '#include "conftst'$i'.h"' >> sub/conftest.c
+      # Using ": > sub/conftst$i.h" creates only sub/conftst1.h with
+      # Solaris 10 /bin/sh.
+      echo '/* dummy */' > sub/conftst$i.h
+    done
+    echo "${am__include} ${am__quote}sub/conftest.Po${am__quote}" > confmf
+
+    # We check with '-c' and '-o' for the sake of the "dashmstdout"
+    # mode.  It turns out that the SunPro C++ compiler does not properly
+    # handle '-M -o', and we need to detect this.  Also, some Intel
+    # versions had trouble with output in subdirs.
+    am__obj=sub/conftest.${OBJEXT-o}
+    am__minus_obj="-o $am__obj"
+    case $depmode in
+    gcc)
+      # This depmode causes a compiler race in universal mode.
+      test "$am__universal" = false || continue
+      ;;
+    nosideeffect)
+      # After this tag, mechanisms are not by side-effect, so they'll
+      # only be used when explicitly requested.
+      if test "x$enable_dependency_tracking" = xyes; then
+	continue
+      else
+	break
+      fi
+      ;;
+    msvc7 | msvc7msys | msvisualcpp | msvcmsys)
+      # This compiler won't grok '-c -o', but also, the minuso test has
+      # not run yet.  These depmodes are late enough in the game, and
+      # so weak that their functioning should not be impacted.
+      am__obj=conftest.${OBJEXT-o}
+      am__minus_obj=
+      ;;
+    none) break ;;
+    esac
+    if depmode=$depmode \
+       source=sub/conftest.c object=$am__obj \
+       depfile=sub/conftest.Po tmpdepfile=sub/conftest.TPo \
+       $SHELL ./depcomp $depcc -c $am__minus_obj sub/conftest.c \
+         >/dev/null 2>conftest.err &&
+       grep sub/conftst1.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep sub/conftst6.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep $am__obj sub/conftest.Po > /dev/null 2>&1 &&
+       ${MAKE-make} -s -f confmf > /dev/null 2>&1; then
+      # icc doesn't choke on unknown options, it will just issue warnings
+      # or remarks (even with -Werror).  So we grep stderr for any message
+      # that says an option was ignored or not supported.
+      # When given -MP, icc 7.0 and 7.1 complain thusly:
+      #   icc: Command line warning: ignoring option '-M'; no argument required
+      # The diagnosis changed in icc 8.0:
+      #   icc: Command line remark: option '-MP' not supported
+      if (grep 'ignoring option' conftest.err ||
+          grep 'not supported' conftest.err) >/dev/null 2>&1; then :; else
+        am_cv_CCAS_dependencies_compiler_type=$depmode
+        break
+      fi
+    fi
+  done
+
+  cd ..
+  rm -rf conftest.dir
+else
+  am_cv_CCAS_dependencies_compiler_type=none
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $am_cv_CCAS_dependencies_compiler_type" >&5
+$as_echo "$am_cv_CCAS_dependencies_compiler_type" >&6; }
+CCASDEPMODE=depmode=$am_cv_CCAS_dependencies_compiler_type
+
+ if
+  test "x$enable_dependency_tracking" != xno \
+  && test "$am_cv_CCAS_dependencies_compiler_type" = gcc3; then
+  am__fastdepCCAS_TRUE=
+  am__fastdepCCAS_FALSE='#'
+else
+  am__fastdepCCAS_TRUE='#'
+  am__fastdepCCAS_FALSE=
+fi
+
+
+# Make sure we can run config.sub.
+$SHELL "$ac_aux_dir/config.sub" sun4 >/dev/null 2>&1 ||
+  as_fn_error $? "cannot run $SHELL $ac_aux_dir/config.sub" "$LINENO" 5
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking build system type" >&5
+$as_echo_n "checking build system type... " >&6; }
+if ${ac_cv_build+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_build_alias=$build_alias
+test "x$ac_build_alias" = x &&
+  ac_build_alias=`$SHELL "$ac_aux_dir/config.guess"`
+test "x$ac_build_alias" = x &&
+  as_fn_error $? "cannot guess build type; you must specify one" "$LINENO" 5
+ac_cv_build=`$SHELL "$ac_aux_dir/config.sub" $ac_build_alias` ||
+  as_fn_error $? "$SHELL $ac_aux_dir/config.sub $ac_build_alias failed" "$LINENO" 5
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_build" >&5
+$as_echo "$ac_cv_build" >&6; }
+case $ac_cv_build in
+*-*-*) ;;
+*) as_fn_error $? "invalid value of canonical build" "$LINENO" 5;;
+esac
+build=$ac_cv_build
+ac_save_IFS=$IFS; IFS='-'
+set x $ac_cv_build
+shift
+build_cpu=$1
+build_vendor=$2
+shift; shift
+# Remember, the first character of IFS is used to create $*,
+# except with old shells:
+build_os=$*
+IFS=$ac_save_IFS
+case $build_os in *\ *) build_os=`echo "$build_os" | sed 's/ /-/g'`;; esac
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking host system type" >&5
+$as_echo_n "checking host system type... " >&6; }
+if ${ac_cv_host+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test "x$host_alias" = x; then
+  ac_cv_host=$ac_cv_build
+else
+  ac_cv_host=`$SHELL "$ac_aux_dir/config.sub" $host_alias` ||
+    as_fn_error $? "$SHELL $ac_aux_dir/config.sub $host_alias failed" "$LINENO" 5
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_host" >&5
+$as_echo "$ac_cv_host" >&6; }
+case $ac_cv_host in
+*-*-*) ;;
+*) as_fn_error $? "invalid value of canonical host" "$LINENO" 5;;
+esac
+host=$ac_cv_host
+ac_save_IFS=$IFS; IFS='-'
+set x $ac_cv_host
+shift
+host_cpu=$1
+host_vendor=$2
+shift; shift
+# Remember, the first character of IFS is used to create $*,
+# except with old shells:
+host_os=$*
+IFS=$ac_save_IFS
+case $host_os in *\ *) host_os=`echo "$host_os" | sed 's/ /-/g'`;; esac
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for a sed that does not truncate output" >&5
+$as_echo_n "checking for a sed that does not truncate output... " >&6; }
+if ${ac_cv_path_SED+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+            ac_script=s/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb/
+     for ac_i in 1 2 3 4 5 6 7; do
+       ac_script="$ac_script$as_nl$ac_script"
+     done
+     echo "$ac_script" 2>/dev/null | sed 99q >conftest.sed
+     { ac_script=; unset ac_script;}
+     if test -z "$SED"; then
+  ac_path_SED_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in sed gsed; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_SED="$as_dir/$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_SED" || continue
+# Check for GNU ac_path_SED and select it if it is found.
+  # Check for GNU $ac_path_SED
+case `"$ac_path_SED" --version 2>&1` in
+*GNU*)
+  ac_cv_path_SED="$ac_path_SED" ac_path_SED_found=:;;
+*)
+  ac_count=0
+  $as_echo_n 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    $as_echo '' >> "conftest.nl"
+    "$ac_path_SED" -f conftest.sed < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_SED_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_SED="$ac_path_SED"
+      ac_path_SED_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_SED_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_SED"; then
+    as_fn_error $? "no acceptable sed could be found in \$PATH" "$LINENO" 5
+  fi
+else
+  ac_cv_path_SED=$SED
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_SED" >&5
+$as_echo "$ac_cv_path_SED" >&6; }
+ SED="$ac_cv_path_SED"
+  rm -f conftest.sed
+
+test -z "$SED" && SED=sed
+Xsed="$SED -e 1s/^X//"
+
+
+
+
+
+
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for grep that handles long lines and -e" >&5
+$as_echo_n "checking for grep that handles long lines and -e... " >&6; }
+if ${ac_cv_path_GREP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -z "$GREP"; then
+  ac_path_GREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in grep ggrep; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_GREP="$as_dir/$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_GREP" || continue
+# Check for GNU ac_path_GREP and select it if it is found.
+  # Check for GNU $ac_path_GREP
+case `"$ac_path_GREP" --version 2>&1` in
+*GNU*)
+  ac_cv_path_GREP="$ac_path_GREP" ac_path_GREP_found=:;;
+*)
+  ac_count=0
+  $as_echo_n 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    $as_echo 'GREP' >> "conftest.nl"
+    "$ac_path_GREP" -e 'GREP$' -e '-(cannot match)-' < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_GREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_GREP="$ac_path_GREP"
+      ac_path_GREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_GREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_GREP"; then
+    as_fn_error $? "no acceptable grep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_GREP=$GREP
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_GREP" >&5
+$as_echo "$ac_cv_path_GREP" >&6; }
+ GREP="$ac_cv_path_GREP"
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for egrep" >&5
+$as_echo_n "checking for egrep... " >&6; }
+if ${ac_cv_path_EGREP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if echo a | $GREP -E '(a|b)' >/dev/null 2>&1
+   then ac_cv_path_EGREP="$GREP -E"
+   else
+     if test -z "$EGREP"; then
+  ac_path_EGREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in egrep; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_EGREP="$as_dir/$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_EGREP" || continue
+# Check for GNU ac_path_EGREP and select it if it is found.
+  # Check for GNU $ac_path_EGREP
+case `"$ac_path_EGREP" --version 2>&1` in
+*GNU*)
+  ac_cv_path_EGREP="$ac_path_EGREP" ac_path_EGREP_found=:;;
+*)
+  ac_count=0
+  $as_echo_n 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    $as_echo 'EGREP' >> "conftest.nl"
+    "$ac_path_EGREP" 'EGREP$' < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_EGREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_EGREP="$ac_path_EGREP"
+      ac_path_EGREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_EGREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_EGREP"; then
+    as_fn_error $? "no acceptable egrep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_EGREP=$EGREP
+fi
+
+   fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_EGREP" >&5
+$as_echo "$ac_cv_path_EGREP" >&6; }
+ EGREP="$ac_cv_path_EGREP"
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for fgrep" >&5
+$as_echo_n "checking for fgrep... " >&6; }
+if ${ac_cv_path_FGREP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if echo 'ab*c' | $GREP -F 'ab*c' >/dev/null 2>&1
+   then ac_cv_path_FGREP="$GREP -F"
+   else
+     if test -z "$FGREP"; then
+  ac_path_FGREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in fgrep; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_FGREP="$as_dir/$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_FGREP" || continue
+# Check for GNU ac_path_FGREP and select it if it is found.
+  # Check for GNU $ac_path_FGREP
+case `"$ac_path_FGREP" --version 2>&1` in
+*GNU*)
+  ac_cv_path_FGREP="$ac_path_FGREP" ac_path_FGREP_found=:;;
+*)
+  ac_count=0
+  $as_echo_n 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    $as_echo 'FGREP' >> "conftest.nl"
+    "$ac_path_FGREP" FGREP < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_FGREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_FGREP="$ac_path_FGREP"
+      ac_path_FGREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_FGREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_FGREP"; then
+    as_fn_error $? "no acceptable fgrep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_FGREP=$FGREP
+fi
+
+   fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_FGREP" >&5
+$as_echo "$ac_cv_path_FGREP" >&6; }
+ FGREP="$ac_cv_path_FGREP"
+
+
+test -z "$GREP" && GREP=grep
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
+ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO
+ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO$ECHO
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking how to print strings" >&5
+$as_echo_n "checking how to print strings... " >&6; }
+# Test print first, because it will be a builtin if present.
+if test "X`( print -r -- -n ) 2>/dev/null`" = X-n && \
+   test "X`print -r -- $ECHO 2>/dev/null`" = "X$ECHO"; then
+  ECHO='print -r --'
+elif test "X`printf %s $ECHO 2>/dev/null`" = "X$ECHO"; then
+  ECHO='printf %s\n'
+else
+  # Use this function as a fallback that always works.
+  func_fallback_echo ()
+  {
+    eval 'cat <<_LTECHO_EOF
+$1
+_LTECHO_EOF'
+  }
+  ECHO='func_fallback_echo'
+fi
+
+# func_echo_all arg...
+# Invoke $ECHO with all args, space-separated.
+func_echo_all ()
+{
+    $ECHO ""
+}
+
+case $ECHO in
+  printf*) { $as_echo "$as_me:${as_lineno-$LINENO}: result: printf" >&5
+$as_echo "printf" >&6; } ;;
+  print*) { $as_echo "$as_me:${as_lineno-$LINENO}: result: print -r" >&5
+$as_echo "print -r" >&6; } ;;
+  *) { $as_echo "$as_me:${as_lineno-$LINENO}: result: cat" >&5
+$as_echo "cat" >&6; } ;;
+esac
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+# Check whether --with-gnu-ld was given.
+if test "${with_gnu_ld+set}" = set; then :
+  withval=$with_gnu_ld; test no = "$withval" || with_gnu_ld=yes
+else
+  with_gnu_ld=no
+fi
+
+ac_prog=ld
+if test yes = "$GCC"; then
+  # Check if gcc -print-prog-name=ld gives a path.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld used by $CC" >&5
+$as_echo_n "checking for ld used by $CC... " >&6; }
+  case $host in
+  *-*-mingw*)
+    # gcc leaves a trailing carriage return, which upsets mingw
+    ac_prog=`($CC -print-prog-name=ld) 2>&5 | tr -d '\015'` ;;
+  *)
+    ac_prog=`($CC -print-prog-name=ld) 2>&5` ;;
+  esac
+  case $ac_prog in
+    # Accept absolute paths.
+    [\\/]* | ?:[\\/]*)
+      re_direlt='/[^/][^/]*/\.\./'
+      # Canonicalize the pathname of ld
+      ac_prog=`$ECHO "$ac_prog"| $SED 's%\\\\%/%g'`
+      while $ECHO "$ac_prog" | $GREP "$re_direlt" > /dev/null 2>&1; do
+	ac_prog=`$ECHO $ac_prog| $SED "s%$re_direlt%/%"`
+      done
+      test -z "$LD" && LD=$ac_prog
+      ;;
+  "")
+    # If it fails, then pretend we aren't using GCC.
+    ac_prog=ld
+    ;;
+  *)
+    # If it is relative, then search for the first ld in PATH.
+    with_gnu_ld=unknown
+    ;;
+  esac
+elif test yes = "$with_gnu_ld"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for GNU ld" >&5
+$as_echo_n "checking for GNU ld... " >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for non-GNU ld" >&5
+$as_echo_n "checking for non-GNU ld... " >&6; }
+fi
+if ${lt_cv_path_LD+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -z "$LD"; then
+  lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+  for ac_dir in $PATH; do
+    IFS=$lt_save_ifs
+    test -z "$ac_dir" && ac_dir=.
+    if test -f "$ac_dir/$ac_prog" || test -f "$ac_dir/$ac_prog$ac_exeext"; then
+      lt_cv_path_LD=$ac_dir/$ac_prog
+      # Check to see if the program is GNU ld.  I'd rather use --version,
+      # but apparently some variants of GNU ld only accept -v.
+      # Break only if it was the GNU/non-GNU ld that we prefer.
+      case `"$lt_cv_path_LD" -v 2>&1 </dev/null` in
+      *GNU* | *'with BFD'*)
+	test no != "$with_gnu_ld" && break
+	;;
+      *)
+	test yes != "$with_gnu_ld" && break
+	;;
+      esac
+    fi
+  done
+  IFS=$lt_save_ifs
+else
+  lt_cv_path_LD=$LD # Let the user override the test with a path.
+fi
+fi
+
+LD=$lt_cv_path_LD
+if test -n "$LD"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $LD" >&5
+$as_echo "$LD" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+test -z "$LD" && as_fn_error $? "no acceptable ld found in \$PATH" "$LINENO" 5
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if the linker ($LD) is GNU ld" >&5
+$as_echo_n "checking if the linker ($LD) is GNU ld... " >&6; }
+if ${lt_cv_prog_gnu_ld+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  # I'd rather use --version here, but apparently some GNU lds only accept -v.
+case `$LD -v 2>&1 </dev/null` in
+*GNU* | *'with BFD'*)
+  lt_cv_prog_gnu_ld=yes
+  ;;
+*)
+  lt_cv_prog_gnu_ld=no
+  ;;
+esac
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_gnu_ld" >&5
+$as_echo "$lt_cv_prog_gnu_ld" >&6; }
+with_gnu_ld=$lt_cv_prog_gnu_ld
+
+
+
+
+
+
+
+
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking how to run the C preprocessor" >&5
+$as_echo_n "checking how to run the C preprocessor... " >&6; }
+# On Suns, sometimes $CPP names a directory.
+if test -n "$CPP" && test -d "$CPP"; then
+  CPP=
+fi
+if test -z "$CPP"; then
+  if ${ac_cv_prog_CPP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+      # Double quotes because CPP needs to be expanded
+    for CPP in "$CC -E" "$CC -E -traditional-cpp" "/lib/cpp"
+    do
+      ac_preproc_ok=false
+for ac_c_preproc_warn_flag in '' yes
+do
+  # Use a header file that comes with gcc, so configuring glibc
+  # with a fresh cross-compiler works.
+  # Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+  # <limits.h> exists even on freestanding compilers.
+  # On the NeXT, cc -E runs the code through the compiler's parser,
+  # not just through cpp. "Syntax error" is here to catch this case.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+		     Syntax error
+_ACEOF
+if ac_fn_c_try_cpp "$LINENO"; then :
+
+else
+  # Broken: fails on valid input.
+continue
+fi
+rm -f conftest.err conftest.i conftest.$ac_ext
+
+  # OK, works on sane cases.  Now check whether nonexistent headers
+  # can be detected and how.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <ac_nonexistent.h>
+_ACEOF
+if ac_fn_c_try_cpp "$LINENO"; then :
+  # Broken: success on invalid input.
+continue
+else
+  # Passes both tests.
+ac_preproc_ok=:
+break
+fi
+rm -f conftest.err conftest.i conftest.$ac_ext
+
+done
+# Because of `break', _AC_PREPROC_IFELSE's cleaning code was skipped.
+rm -f conftest.i conftest.err conftest.$ac_ext
+if $ac_preproc_ok; then :
+  break
+fi
+
+    done
+    ac_cv_prog_CPP=$CPP
+
+fi
+  CPP=$ac_cv_prog_CPP
+else
+  ac_cv_prog_CPP=$CPP
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $CPP" >&5
+$as_echo "$CPP" >&6; }
+ac_preproc_ok=false
+for ac_c_preproc_warn_flag in '' yes
+do
+  # Use a header file that comes with gcc, so configuring glibc
+  # with a fresh cross-compiler works.
+  # Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+  # <limits.h> exists even on freestanding compilers.
+  # On the NeXT, cc -E runs the code through the compiler's parser,
+  # not just through cpp. "Syntax error" is here to catch this case.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+		     Syntax error
+_ACEOF
+if ac_fn_c_try_cpp "$LINENO"; then :
+
+else
+  # Broken: fails on valid input.
+continue
+fi
+rm -f conftest.err conftest.i conftest.$ac_ext
+
+  # OK, works on sane cases.  Now check whether nonexistent headers
+  # can be detected and how.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <ac_nonexistent.h>
+_ACEOF
+if ac_fn_c_try_cpp "$LINENO"; then :
+  # Broken: success on invalid input.
+continue
+else
+  # Passes both tests.
+ac_preproc_ok=:
+break
+fi
+rm -f conftest.err conftest.i conftest.$ac_ext
+
+done
+# Because of `break', _AC_PREPROC_IFELSE's cleaning code was skipped.
+rm -f conftest.i conftest.err conftest.$ac_ext
+if $ac_preproc_ok; then :
+
+else
+  { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "C preprocessor \"$CPP\" fails sanity check
+See \`config.log' for more details" "$LINENO" 5; }
+fi
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+for ac_prog in gawk mawk nawk awk
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_AWK+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$AWK"; then
+  ac_cv_prog_AWK="$AWK" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AWK="$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+AWK=$ac_cv_prog_AWK
+if test -n "$AWK"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $AWK" >&5
+$as_echo "$AWK" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  test -n "$AWK" && break
+done
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ln -s works" >&5
+$as_echo_n "checking whether ln -s works... " >&6; }
+LN_S=$as_ln_s
+if test "$LN_S" = "ln -s"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no, using $LN_S" >&5
+$as_echo "no, using $LN_S" >&6; }
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${MAKE-make} sets \$(MAKE)" >&5
+$as_echo_n "checking whether ${MAKE-make} sets \$(MAKE)... " >&6; }
+set x ${MAKE-make}
+ac_make=`$as_echo "$2" | sed 's/+/p/g; s/[^a-zA-Z0-9_]/_/g'`
+if eval \${ac_cv_prog_make_${ac_make}_set+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat >conftest.make <<\_ACEOF
+SHELL = /bin/sh
+all:
+	@echo '@@@%%%=$(MAKE)=@@@%%%'
+_ACEOF
+# GNU make sometimes prints "make[1]: Entering ...", which would confuse us.
+case `${MAKE-make} -f conftest.make 2>/dev/null` in
+  *@@@%%%=?*=@@@%%%*)
+    eval ac_cv_prog_make_${ac_make}_set=yes;;
+  *)
+    eval ac_cv_prog_make_${ac_make}_set=no;;
+esac
+rm -f conftest.make
+fi
+if eval test \$ac_cv_prog_make_${ac_make}_set = yes; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+  SET_MAKE=
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+  SET_MAKE="MAKE=${MAKE-make}"
+fi
+
+
+case `pwd` in
+  *\ * | *\	*)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Libtool does not cope well with whitespace in \`pwd\`" >&5
+$as_echo "$as_me: WARNING: Libtool does not cope well with whitespace in \`pwd\`" >&2;} ;;
+esac
+
+
+
+macro_version='2.4.6'
+macro_revision='2.4.6'
+
+
+
+
+
+
+
+
+
+
+
+
+
+ltmain=$ac_aux_dir/ltmain.sh
+
+# Backslashify metacharacters that are still active within
+# double-quoted strings.
+sed_quote_subst='s/\(["`$\\]\)/\\\1/g'
+
+# Same as above, but do not quote variable references.
+double_quote_subst='s/\(["`\\]\)/\\\1/g'
+
+# Sed substitution to delay expansion of an escaped shell variable in a
+# double_quote_subst'ed string.
+delay_variable_subst='s/\\\\\\\\\\\$/\\\\\\$/g'
+
+# Sed substitution to delay expansion of an escaped single quote.
+delay_single_quote_subst='s/'\''/'\'\\\\\\\'\''/g'
+
+# Sed substitution to avoid accidental globbing in evaled expressions
+no_glob_subst='s/\*/\\\*/g'
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for BSD- or MS-compatible name lister (nm)" >&5
+$as_echo_n "checking for BSD- or MS-compatible name lister (nm)... " >&6; }
+if ${lt_cv_path_NM+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$NM"; then
+  # Let the user override the test.
+  lt_cv_path_NM=$NM
+else
+  lt_nm_to_check=${ac_tool_prefix}nm
+  if test -n "$ac_tool_prefix" && test "$build" = "$host"; then
+    lt_nm_to_check="$lt_nm_to_check nm"
+  fi
+  for lt_tmp_nm in $lt_nm_to_check; do
+    lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+    for ac_dir in $PATH /usr/ccs/bin/elf /usr/ccs/bin /usr/ucb /bin; do
+      IFS=$lt_save_ifs
+      test -z "$ac_dir" && ac_dir=.
+      tmp_nm=$ac_dir/$lt_tmp_nm
+      if test -f "$tmp_nm" || test -f "$tmp_nm$ac_exeext"; then
+	# Check to see if the nm accepts a BSD-compat flag.
+	# Adding the 'sed 1q' prevents false positives on HP-UX, which says:
+	#   nm: unknown option "B" ignored
+	# Tru64's nm complains that /dev/null is an invalid object file
+	# MSYS converts /dev/null to NUL, MinGW nm treats NUL as empty
+	case $build_os in
+	mingw*) lt_bad_file=conftest.nm/nofile ;;
+	*) lt_bad_file=/dev/null ;;
+	esac
+	case `"$tmp_nm" -B $lt_bad_file 2>&1 | sed '1q'` in
+	*$lt_bad_file* | *'Invalid file or object type'*)
+	  lt_cv_path_NM="$tmp_nm -B"
+	  break 2
+	  ;;
+	*)
+	  case `"$tmp_nm" -p /dev/null 2>&1 | sed '1q'` in
+	  */dev/null*)
+	    lt_cv_path_NM="$tmp_nm -p"
+	    break 2
+	    ;;
+	  *)
+	    lt_cv_path_NM=${lt_cv_path_NM="$tmp_nm"} # keep the first match, but
+	    continue # so that we can try to find one that supports BSD flags
+	    ;;
+	  esac
+	  ;;
+	esac
+      fi
+    done
+    IFS=$lt_save_ifs
+  done
+  : ${lt_cv_path_NM=no}
+fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_path_NM" >&5
+$as_echo "$lt_cv_path_NM" >&6; }
+if test no != "$lt_cv_path_NM"; then
+  NM=$lt_cv_path_NM
+else
+  # Didn't find any BSD compatible name lister, look for dumpbin.
+  if test -n "$DUMPBIN"; then :
+    # Let the user override the test.
+  else
+    if test -n "$ac_tool_prefix"; then
+  for ac_prog in dumpbin "link -dump"
+  do
+    # Extract the first word of "$ac_tool_prefix$ac_prog", so it can be a program name with args.
+set dummy $ac_tool_prefix$ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_DUMPBIN+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$DUMPBIN"; then
+  ac_cv_prog_DUMPBIN="$DUMPBIN" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_DUMPBIN="$ac_tool_prefix$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+DUMPBIN=$ac_cv_prog_DUMPBIN
+if test -n "$DUMPBIN"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $DUMPBIN" >&5
+$as_echo "$DUMPBIN" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+    test -n "$DUMPBIN" && break
+  done
+fi
+if test -z "$DUMPBIN"; then
+  ac_ct_DUMPBIN=$DUMPBIN
+  for ac_prog in dumpbin "link -dump"
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_DUMPBIN+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_DUMPBIN"; then
+  ac_cv_prog_ac_ct_DUMPBIN="$ac_ct_DUMPBIN" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_DUMPBIN="$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_DUMPBIN=$ac_cv_prog_ac_ct_DUMPBIN
+if test -n "$ac_ct_DUMPBIN"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_DUMPBIN" >&5
+$as_echo "$ac_ct_DUMPBIN" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  test -n "$ac_ct_DUMPBIN" && break
+done
+
+  if test "x$ac_ct_DUMPBIN" = x; then
+    DUMPBIN=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    DUMPBIN=$ac_ct_DUMPBIN
+  fi
+fi
+
+    case `$DUMPBIN -symbols -headers /dev/null 2>&1 | sed '1q'` in
+    *COFF*)
+      DUMPBIN="$DUMPBIN -symbols -headers"
+      ;;
+    *)
+      DUMPBIN=:
+      ;;
+    esac
+  fi
+
+  if test : != "$DUMPBIN"; then
+    NM=$DUMPBIN
+  fi
+fi
+test -z "$NM" && NM=nm
+
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking the name lister ($NM) interface" >&5
+$as_echo_n "checking the name lister ($NM) interface... " >&6; }
+if ${lt_cv_nm_interface+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_nm_interface="BSD nm"
+  echo "int some_variable = 0;" > conftest.$ac_ext
+  (eval echo "\"\$as_me:$LINENO: $ac_compile\"" >&5)
+  (eval "$ac_compile" 2>conftest.err)
+  cat conftest.err >&5
+  (eval echo "\"\$as_me:$LINENO: $NM \\\"conftest.$ac_objext\\\"\"" >&5)
+  (eval "$NM \"conftest.$ac_objext\"" 2>conftest.err > conftest.out)
+  cat conftest.err >&5
+  (eval echo "\"\$as_me:$LINENO: output\"" >&5)
+  cat conftest.out >&5
+  if $GREP 'External.*some_variable' conftest.out > /dev/null; then
+    lt_cv_nm_interface="MS dumpbin"
+  fi
+  rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_nm_interface" >&5
+$as_echo "$lt_cv_nm_interface" >&6; }
+
+# find the maximum length of command line arguments
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking the maximum length of command line arguments" >&5
+$as_echo_n "checking the maximum length of command line arguments... " >&6; }
+if ${lt_cv_sys_max_cmd_len+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+    i=0
+  teststring=ABCD
+
+  case $build_os in
+  msdosdjgpp*)
+    # On DJGPP, this test can blow up pretty badly due to problems in libc
+    # (any single argument exceeding 2000 bytes causes a buffer overrun
+    # during glob expansion).  Even if it were fixed, the result of this
+    # check would be larger than it should be.
+    lt_cv_sys_max_cmd_len=12288;    # 12K is about right
+    ;;
+
+  gnu*)
+    # Under GNU Hurd, this test is not required because there is
+    # no limit to the length of command line arguments.
+    # Libtool will interpret -1 as no limit whatsoever
+    lt_cv_sys_max_cmd_len=-1;
+    ;;
+
+  cygwin* | mingw* | cegcc*)
+    # On Win9x/ME, this test blows up -- it succeeds, but takes
+    # about 5 minutes as the teststring grows exponentially.
+    # Worse, since 9x/ME are not pre-emptively multitasking,
+    # you end up with a "frozen" computer, even though with patience
+    # the test eventually succeeds (with a max line length of 256k).
+    # Instead, let's just punt: use the minimum linelength reported by
+    # all of the supported platforms: 8192 (on NT/2K/XP).
+    lt_cv_sys_max_cmd_len=8192;
+    ;;
+
+  mint*)
+    # On MiNT this can take a long time and run out of memory.
+    lt_cv_sys_max_cmd_len=8192;
+    ;;
+
+  amigaos*)
+    # On AmigaOS with pdksh, this test takes hours, literally.
+    # So we just punt and use a minimum line length of 8192.
+    lt_cv_sys_max_cmd_len=8192;
+    ;;
+
+  bitrig* | darwin* | dragonfly* | freebsd* | netbsd* | openbsd*)
+    # This has been around since 386BSD, at least.  Likely further.
+    if test -x /sbin/sysctl; then
+      lt_cv_sys_max_cmd_len=`/sbin/sysctl -n kern.argmax`
+    elif test -x /usr/sbin/sysctl; then
+      lt_cv_sys_max_cmd_len=`/usr/sbin/sysctl -n kern.argmax`
+    else
+      lt_cv_sys_max_cmd_len=65536	# usable default for all BSDs
+    fi
+    # And add a safety zone
+    lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \/ 4`
+    lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \* 3`
+    ;;
+
+  interix*)
+    # We know the value 262144 and hardcode it with a safety zone (like BSD)
+    lt_cv_sys_max_cmd_len=196608
+    ;;
+
+  os2*)
+    # The test takes a long time on OS/2.
+    lt_cv_sys_max_cmd_len=8192
+    ;;
+
+  osf*)
+    # Dr. Hans Ekkehard Plesser reports seeing a kernel panic running configure
+    # due to this test when exec_disable_arg_limit is 1 on Tru64. It is not
+    # nice to cause kernel panics so lets avoid the loop below.
+    # First set a reasonable default.
+    lt_cv_sys_max_cmd_len=16384
+    #
+    if test -x /sbin/sysconfig; then
+      case `/sbin/sysconfig -q proc exec_disable_arg_limit` in
+        *1*) lt_cv_sys_max_cmd_len=-1 ;;
+      esac
+    fi
+    ;;
+  sco3.2v5*)
+    lt_cv_sys_max_cmd_len=102400
+    ;;
+  sysv5* | sco5v6* | sysv4.2uw2*)
+    kargmax=`grep ARG_MAX /etc/conf/cf.d/stune 2>/dev/null`
+    if test -n "$kargmax"; then
+      lt_cv_sys_max_cmd_len=`echo $kargmax | sed 's/.*[	 ]//'`
+    else
+      lt_cv_sys_max_cmd_len=32768
+    fi
+    ;;
+  *)
+    lt_cv_sys_max_cmd_len=`(getconf ARG_MAX) 2> /dev/null`
+    if test -n "$lt_cv_sys_max_cmd_len" && \
+       test undefined != "$lt_cv_sys_max_cmd_len"; then
+      lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \/ 4`
+      lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \* 3`
+    else
+      # Make teststring a little bigger before we do anything with it.
+      # a 1K string should be a reasonable start.
+      for i in 1 2 3 4 5 6 7 8; do
+        teststring=$teststring$teststring
+      done
+      SHELL=${SHELL-${CONFIG_SHELL-/bin/sh}}
+      # If test is not a shell built-in, we'll probably end up computing a
+      # maximum length that is only half of the actual maximum length, but
+      # we can't tell.
+      while { test X`env echo "$teststring$teststring" 2>/dev/null` \
+	         = "X$teststring$teststring"; } >/dev/null 2>&1 &&
+	      test 17 != "$i" # 1/2 MB should be enough
+      do
+        i=`expr $i + 1`
+        teststring=$teststring$teststring
+      done
+      # Only check the string length outside the loop.
+      lt_cv_sys_max_cmd_len=`expr "X$teststring" : ".*" 2>&1`
+      teststring=
+      # Add a significant safety factor because C++ compilers can tack on
+      # massive amounts of additional arguments before passing them to the
+      # linker.  It appears as though 1/2 is a usable value.
+      lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \/ 2`
+    fi
+    ;;
+  esac
+
+fi
+
+if test -n "$lt_cv_sys_max_cmd_len"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_sys_max_cmd_len" >&5
+$as_echo "$lt_cv_sys_max_cmd_len" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: none" >&5
+$as_echo "none" >&6; }
+fi
+max_cmd_len=$lt_cv_sys_max_cmd_len
+
+
+
+
+
+
+: ${CP="cp -f"}
+: ${MV="mv -f"}
+: ${RM="rm -f"}
+
+if ( (MAIL=60; unset MAIL) || exit) >/dev/null 2>&1; then
+  lt_unset=unset
+else
+  lt_unset=false
+fi
+
+
+
+
+
+# test EBCDIC or ASCII
+case `echo X|tr X '\101'` in
+ A) # ASCII based system
+    # \n is not interpreted correctly by Solaris 8 /usr/ucb/tr
+  lt_SP2NL='tr \040 \012'
+  lt_NL2SP='tr \015\012 \040\040'
+  ;;
+ *) # EBCDIC based system
+  lt_SP2NL='tr \100 \n'
+  lt_NL2SP='tr \r\n \100\100'
+  ;;
+esac
+
+
+
+
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking how to convert $build file names to $host format" >&5
+$as_echo_n "checking how to convert $build file names to $host format... " >&6; }
+if ${lt_cv_to_host_file_cmd+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  case $host in
+  *-*-mingw* )
+    case $build in
+      *-*-mingw* ) # actually msys
+        lt_cv_to_host_file_cmd=func_convert_file_msys_to_w32
+        ;;
+      *-*-cygwin* )
+        lt_cv_to_host_file_cmd=func_convert_file_cygwin_to_w32
+        ;;
+      * ) # otherwise, assume *nix
+        lt_cv_to_host_file_cmd=func_convert_file_nix_to_w32
+        ;;
+    esac
+    ;;
+  *-*-cygwin* )
+    case $build in
+      *-*-mingw* ) # actually msys
+        lt_cv_to_host_file_cmd=func_convert_file_msys_to_cygwin
+        ;;
+      *-*-cygwin* )
+        lt_cv_to_host_file_cmd=func_convert_file_noop
+        ;;
+      * ) # otherwise, assume *nix
+        lt_cv_to_host_file_cmd=func_convert_file_nix_to_cygwin
+        ;;
+    esac
+    ;;
+  * ) # unhandled hosts (and "normal" native builds)
+    lt_cv_to_host_file_cmd=func_convert_file_noop
+    ;;
+esac
+
+fi
+
+to_host_file_cmd=$lt_cv_to_host_file_cmd
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_to_host_file_cmd" >&5
+$as_echo "$lt_cv_to_host_file_cmd" >&6; }
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking how to convert $build file names to toolchain format" >&5
+$as_echo_n "checking how to convert $build file names to toolchain format... " >&6; }
+if ${lt_cv_to_tool_file_cmd+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  #assume ordinary cross tools, or native build.
+lt_cv_to_tool_file_cmd=func_convert_file_noop
+case $host in
+  *-*-mingw* )
+    case $build in
+      *-*-mingw* ) # actually msys
+        lt_cv_to_tool_file_cmd=func_convert_file_msys_to_w32
+        ;;
+    esac
+    ;;
+esac
+
+fi
+
+to_tool_file_cmd=$lt_cv_to_tool_file_cmd
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_to_tool_file_cmd" >&5
+$as_echo "$lt_cv_to_tool_file_cmd" >&6; }
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $LD option to reload object files" >&5
+$as_echo_n "checking for $LD option to reload object files... " >&6; }
+if ${lt_cv_ld_reload_flag+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_ld_reload_flag='-r'
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_ld_reload_flag" >&5
+$as_echo "$lt_cv_ld_reload_flag" >&6; }
+reload_flag=$lt_cv_ld_reload_flag
+case $reload_flag in
+"" | " "*) ;;
+*) reload_flag=" $reload_flag" ;;
+esac
+reload_cmds='$LD$reload_flag -o $output$reload_objs'
+case $host_os in
+  cygwin* | mingw* | pw32* | cegcc*)
+    if test yes != "$GCC"; then
+      reload_cmds=false
+    fi
+    ;;
+  darwin*)
+    if test yes = "$GCC"; then
+      reload_cmds='$LTCC $LTCFLAGS -nostdlib $wl-r -o $output$reload_objs'
+    else
+      reload_cmds='$LD$reload_flag -o $output$reload_objs'
+    fi
+    ;;
+esac
+
+
+
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}objdump", so it can be a program name with args.
+set dummy ${ac_tool_prefix}objdump; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_OBJDUMP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$OBJDUMP"; then
+  ac_cv_prog_OBJDUMP="$OBJDUMP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_OBJDUMP="${ac_tool_prefix}objdump"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+OBJDUMP=$ac_cv_prog_OBJDUMP
+if test -n "$OBJDUMP"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $OBJDUMP" >&5
+$as_echo "$OBJDUMP" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_OBJDUMP"; then
+  ac_ct_OBJDUMP=$OBJDUMP
+  # Extract the first word of "objdump", so it can be a program name with args.
+set dummy objdump; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_OBJDUMP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_OBJDUMP"; then
+  ac_cv_prog_ac_ct_OBJDUMP="$ac_ct_OBJDUMP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_OBJDUMP="objdump"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_OBJDUMP=$ac_cv_prog_ac_ct_OBJDUMP
+if test -n "$ac_ct_OBJDUMP"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_OBJDUMP" >&5
+$as_echo "$ac_ct_OBJDUMP" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_OBJDUMP" = x; then
+    OBJDUMP="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    OBJDUMP=$ac_ct_OBJDUMP
+  fi
+else
+  OBJDUMP="$ac_cv_prog_OBJDUMP"
+fi
+
+test -z "$OBJDUMP" && OBJDUMP=objdump
+
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking how to recognize dependent libraries" >&5
+$as_echo_n "checking how to recognize dependent libraries... " >&6; }
+if ${lt_cv_deplibs_check_method+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_file_magic_cmd='$MAGIC_CMD'
+lt_cv_file_magic_test_file=
+lt_cv_deplibs_check_method='unknown'
+# Need to set the preceding variable on all platforms that support
+# interlibrary dependencies.
+# 'none' -- dependencies not supported.
+# 'unknown' -- same as none, but documents that we really don't know.
+# 'pass_all' -- all dependencies passed with no checks.
+# 'test_compile' -- check by making test program.
+# 'file_magic [[regex]]' -- check by looking for files in library path
+# that responds to the $file_magic_cmd with a given extended regex.
+# If you have 'file' or equivalent on your system and you're not sure
+# whether 'pass_all' will *always* work, you probably want this one.
+
+case $host_os in
+aix[4-9]*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+beos*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+bsdi[45]*)
+  lt_cv_deplibs_check_method='file_magic ELF [0-9][0-9]*-bit [ML]SB (shared object|dynamic lib)'
+  lt_cv_file_magic_cmd='/usr/bin/file -L'
+  lt_cv_file_magic_test_file=/shlib/libc.so
+  ;;
+
+cygwin*)
+  # func_win32_libid is a shell function defined in ltmain.sh
+  lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
+  lt_cv_file_magic_cmd='func_win32_libid'
+  ;;
+
+mingw* | pw32*)
+  # Base MSYS/MinGW do not provide the 'file' command needed by
+  # func_win32_libid shell function, so use a weaker test based on 'objdump',
+  # unless we find 'file', for example because we are cross-compiling.
+  if ( file / ) >/dev/null 2>&1; then
+    lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
+    lt_cv_file_magic_cmd='func_win32_libid'
+  else
+    # Keep this pattern in sync with the one in func_win32_libid.
+    lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)'
+    lt_cv_file_magic_cmd='$OBJDUMP -f'
+  fi
+  ;;
+
+cegcc*)
+  # use the weaker test based on 'objdump'. See mingw*.
+  lt_cv_deplibs_check_method='file_magic file format pe-arm-.*little(.*architecture: arm)?'
+  lt_cv_file_magic_cmd='$OBJDUMP -f'
+  ;;
+
+darwin* | rhapsody*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+freebsd* | dragonfly*)
+  if echo __ELF__ | $CC -E - | $GREP __ELF__ > /dev/null; then
+    case $host_cpu in
+    i*86 )
+      # Not sure whether the presence of OpenBSD here was a mistake.
+      # Let's accept both of them until this is cleared up.
+      lt_cv_deplibs_check_method='file_magic (FreeBSD|OpenBSD|DragonFly)/i[3-9]86 (compact )?demand paged shared library'
+      lt_cv_file_magic_cmd=/usr/bin/file
+      lt_cv_file_magic_test_file=`echo /usr/lib/libc.so.*`
+      ;;
+    esac
+  else
+    lt_cv_deplibs_check_method=pass_all
+  fi
+  ;;
+
+haiku*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+hpux10.20* | hpux11*)
+  lt_cv_file_magic_cmd=/usr/bin/file
+  case $host_cpu in
+  ia64*)
+    lt_cv_deplibs_check_method='file_magic (s[0-9][0-9][0-9]|ELF-[0-9][0-9]) shared object file - IA64'
+    lt_cv_file_magic_test_file=/usr/lib/hpux32/libc.so
+    ;;
+  hppa*64*)
+    lt_cv_deplibs_check_method='file_magic (s[0-9][0-9][0-9]|ELF[ -][0-9][0-9])(-bit)?( [LM]SB)? shared object( file)?[, -]* PA-RISC [0-9]\.[0-9]'
+    lt_cv_file_magic_test_file=/usr/lib/pa20_64/libc.sl
+    ;;
+  *)
+    lt_cv_deplibs_check_method='file_magic (s[0-9][0-9][0-9]|PA-RISC[0-9]\.[0-9]) shared library'
+    lt_cv_file_magic_test_file=/usr/lib/libc.sl
+    ;;
+  esac
+  ;;
+
+interix[3-9]*)
+  # PIC code is broken on Interix 3.x, that's why |\.a not |_pic\.a here
+  lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so|\.a)$'
+  ;;
+
+irix5* | irix6* | nonstopux*)
+  case $LD in
+  *-32|*"-32 ") libmagic=32-bit;;
+  *-n32|*"-n32 ") libmagic=N32;;
+  *-64|*"-64 ") libmagic=64-bit;;
+  *) libmagic=never-match;;
+  esac
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+# This must be glibc/ELF.
+linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+netbsd*)
+  if echo __ELF__ | $CC -E - | $GREP __ELF__ > /dev/null; then
+    lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so\.[0-9]+\.[0-9]+|_pic\.a)$'
+  else
+    lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so|_pic\.a)$'
+  fi
+  ;;
+
+newos6*)
+  lt_cv_deplibs_check_method='file_magic ELF [0-9][0-9]*-bit [ML]SB (executable|dynamic lib)'
+  lt_cv_file_magic_cmd=/usr/bin/file
+  lt_cv_file_magic_test_file=/usr/lib/libnls.so
+  ;;
+
+*nto* | *qnx*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+openbsd* | bitrig*)
+  if test -z "`echo __ELF__ | $CC -E - | $GREP __ELF__`"; then
+    lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so\.[0-9]+\.[0-9]+|\.so|_pic\.a)$'
+  else
+    lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so\.[0-9]+\.[0-9]+|_pic\.a)$'
+  fi
+  ;;
+
+osf3* | osf4* | osf5*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+rdos*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+solaris*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX* | sysv4*uw2*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+sysv4 | sysv4.3*)
+  case $host_vendor in
+  motorola)
+    lt_cv_deplibs_check_method='file_magic ELF [0-9][0-9]*-bit [ML]SB (shared object|dynamic lib) M[0-9][0-9]* Version [0-9]'
+    lt_cv_file_magic_test_file=`echo /usr/lib/libc.so*`
+    ;;
+  ncr)
+    lt_cv_deplibs_check_method=pass_all
+    ;;
+  sequent)
+    lt_cv_file_magic_cmd='/bin/file'
+    lt_cv_deplibs_check_method='file_magic ELF [0-9][0-9]*-bit [LM]SB (shared object|dynamic lib )'
+    ;;
+  sni)
+    lt_cv_file_magic_cmd='/bin/file'
+    lt_cv_deplibs_check_method="file_magic ELF [0-9][0-9]*-bit [LM]SB dynamic lib"
+    lt_cv_file_magic_test_file=/lib/libc.so
+    ;;
+  siemens)
+    lt_cv_deplibs_check_method=pass_all
+    ;;
+  pc)
+    lt_cv_deplibs_check_method=pass_all
+    ;;
+  esac
+  ;;
+
+tpf*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+os2*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+esac
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_deplibs_check_method" >&5
+$as_echo "$lt_cv_deplibs_check_method" >&6; }
+
+file_magic_glob=
+want_nocaseglob=no
+if test "$build" = "$host"; then
+  case $host_os in
+  mingw* | pw32*)
+    if ( shopt | grep nocaseglob ) >/dev/null 2>&1; then
+      want_nocaseglob=yes
+    else
+      file_magic_glob=`echo aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ | $SED -e "s/\(..\)/s\/[\1]\/[\1]\/g;/g"`
+    fi
+    ;;
+  esac
+fi
+
+file_magic_cmd=$lt_cv_file_magic_cmd
+deplibs_check_method=$lt_cv_deplibs_check_method
+test -z "$deplibs_check_method" && deplibs_check_method=unknown
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}dlltool", so it can be a program name with args.
+set dummy ${ac_tool_prefix}dlltool; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_DLLTOOL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$DLLTOOL"; then
+  ac_cv_prog_DLLTOOL="$DLLTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_DLLTOOL="${ac_tool_prefix}dlltool"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+DLLTOOL=$ac_cv_prog_DLLTOOL
+if test -n "$DLLTOOL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $DLLTOOL" >&5
+$as_echo "$DLLTOOL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_DLLTOOL"; then
+  ac_ct_DLLTOOL=$DLLTOOL
+  # Extract the first word of "dlltool", so it can be a program name with args.
+set dummy dlltool; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_DLLTOOL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_DLLTOOL"; then
+  ac_cv_prog_ac_ct_DLLTOOL="$ac_ct_DLLTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_DLLTOOL="dlltool"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_DLLTOOL=$ac_cv_prog_ac_ct_DLLTOOL
+if test -n "$ac_ct_DLLTOOL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_DLLTOOL" >&5
+$as_echo "$ac_ct_DLLTOOL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_DLLTOOL" = x; then
+    DLLTOOL="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    DLLTOOL=$ac_ct_DLLTOOL
+  fi
+else
+  DLLTOOL="$ac_cv_prog_DLLTOOL"
+fi
+
+test -z "$DLLTOOL" && DLLTOOL=dlltool
+
+
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking how to associate runtime and link libraries" >&5
+$as_echo_n "checking how to associate runtime and link libraries... " >&6; }
+if ${lt_cv_sharedlib_from_linklib_cmd+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_sharedlib_from_linklib_cmd='unknown'
+
+case $host_os in
+cygwin* | mingw* | pw32* | cegcc*)
+  # two different shell functions defined in ltmain.sh;
+  # decide which one to use based on capabilities of $DLLTOOL
+  case `$DLLTOOL --help 2>&1` in
+  *--identify-strict*)
+    lt_cv_sharedlib_from_linklib_cmd=func_cygming_dll_for_implib
+    ;;
+  *)
+    lt_cv_sharedlib_from_linklib_cmd=func_cygming_dll_for_implib_fallback
+    ;;
+  esac
+  ;;
+*)
+  # fallback: assume linklib IS sharedlib
+  lt_cv_sharedlib_from_linklib_cmd=$ECHO
+  ;;
+esac
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_sharedlib_from_linklib_cmd" >&5
+$as_echo "$lt_cv_sharedlib_from_linklib_cmd" >&6; }
+sharedlib_from_linklib_cmd=$lt_cv_sharedlib_from_linklib_cmd
+test -z "$sharedlib_from_linklib_cmd" && sharedlib_from_linklib_cmd=$ECHO
+
+
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  for ac_prog in ar
+  do
+    # Extract the first word of "$ac_tool_prefix$ac_prog", so it can be a program name with args.
+set dummy $ac_tool_prefix$ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_AR+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$AR"; then
+  ac_cv_prog_AR="$AR" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AR="$ac_tool_prefix$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+AR=$ac_cv_prog_AR
+if test -n "$AR"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $AR" >&5
+$as_echo "$AR" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+    test -n "$AR" && break
+  done
+fi
+if test -z "$AR"; then
+  ac_ct_AR=$AR
+  for ac_prog in ar
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_AR+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_AR"; then
+  ac_cv_prog_ac_ct_AR="$ac_ct_AR" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_AR="$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_AR=$ac_cv_prog_ac_ct_AR
+if test -n "$ac_ct_AR"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_AR" >&5
+$as_echo "$ac_ct_AR" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  test -n "$ac_ct_AR" && break
+done
+
+  if test "x$ac_ct_AR" = x; then
+    AR="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    AR=$ac_ct_AR
+  fi
+fi
+
+: ${AR=ar}
+: ${AR_FLAGS=cru}
+
+
+
+
+
+
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for archiver @FILE support" >&5
+$as_echo_n "checking for archiver @FILE support... " >&6; }
+if ${lt_cv_ar_at_file+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_ar_at_file=no
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  echo conftest.$ac_objext > conftest.lst
+      lt_ar_try='$AR $AR_FLAGS libconftest.a @conftest.lst >&5'
+      { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$lt_ar_try\""; } >&5
+  (eval $lt_ar_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+      if test 0 -eq "$ac_status"; then
+	# Ensure the archiver fails upon bogus file names.
+	rm -f conftest.$ac_objext libconftest.a
+	{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$lt_ar_try\""; } >&5
+  (eval $lt_ar_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+	if test 0 -ne "$ac_status"; then
+          lt_cv_ar_at_file=@
+        fi
+      fi
+      rm -f conftest.* libconftest.a
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_ar_at_file" >&5
+$as_echo "$lt_cv_ar_at_file" >&6; }
+
+if test no = "$lt_cv_ar_at_file"; then
+  archiver_list_spec=
+else
+  archiver_list_spec=$lt_cv_ar_at_file
+fi
+
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}strip", so it can be a program name with args.
+set dummy ${ac_tool_prefix}strip; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_STRIP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$STRIP"; then
+  ac_cv_prog_STRIP="$STRIP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_STRIP="${ac_tool_prefix}strip"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+STRIP=$ac_cv_prog_STRIP
+if test -n "$STRIP"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $STRIP" >&5
+$as_echo "$STRIP" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_STRIP"; then
+  ac_ct_STRIP=$STRIP
+  # Extract the first word of "strip", so it can be a program name with args.
+set dummy strip; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_STRIP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_STRIP"; then
+  ac_cv_prog_ac_ct_STRIP="$ac_ct_STRIP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_STRIP="strip"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_STRIP=$ac_cv_prog_ac_ct_STRIP
+if test -n "$ac_ct_STRIP"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_STRIP" >&5
+$as_echo "$ac_ct_STRIP" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_STRIP" = x; then
+    STRIP=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    STRIP=$ac_ct_STRIP
+  fi
+else
+  STRIP="$ac_cv_prog_STRIP"
+fi
+
+test -z "$STRIP" && STRIP=:
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}ranlib", so it can be a program name with args.
+set dummy ${ac_tool_prefix}ranlib; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_RANLIB+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$RANLIB"; then
+  ac_cv_prog_RANLIB="$RANLIB" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_RANLIB="${ac_tool_prefix}ranlib"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+RANLIB=$ac_cv_prog_RANLIB
+if test -n "$RANLIB"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $RANLIB" >&5
+$as_echo "$RANLIB" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_RANLIB"; then
+  ac_ct_RANLIB=$RANLIB
+  # Extract the first word of "ranlib", so it can be a program name with args.
+set dummy ranlib; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_RANLIB+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_RANLIB"; then
+  ac_cv_prog_ac_ct_RANLIB="$ac_ct_RANLIB" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_RANLIB="ranlib"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_RANLIB=$ac_cv_prog_ac_ct_RANLIB
+if test -n "$ac_ct_RANLIB"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_RANLIB" >&5
+$as_echo "$ac_ct_RANLIB" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_RANLIB" = x; then
+    RANLIB=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    RANLIB=$ac_ct_RANLIB
+  fi
+else
+  RANLIB="$ac_cv_prog_RANLIB"
+fi
+
+test -z "$RANLIB" && RANLIB=:
+
+
+
+
+
+
+# Determine commands to create old-style static archives.
+old_archive_cmds='$AR $AR_FLAGS $oldlib$oldobjs'
+old_postinstall_cmds='chmod 644 $oldlib'
+old_postuninstall_cmds=
+
+if test -n "$RANLIB"; then
+  case $host_os in
+  bitrig* | openbsd*)
+    old_postinstall_cmds="$old_postinstall_cmds~\$RANLIB -t \$tool_oldlib"
+    ;;
+  *)
+    old_postinstall_cmds="$old_postinstall_cmds~\$RANLIB \$tool_oldlib"
+    ;;
+  esac
+  old_archive_cmds="$old_archive_cmds~\$RANLIB \$tool_oldlib"
+fi
+
+case $host_os in
+  darwin*)
+    lock_old_archive_extraction=yes ;;
+  *)
+    lock_old_archive_extraction=no ;;
+esac
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+# If no C compiler was specified, use CC.
+LTCC=${LTCC-"$CC"}
+
+# If no C compiler flags were specified, use CFLAGS.
+LTCFLAGS=${LTCFLAGS-"$CFLAGS"}
+
+# Allow CC to be a program name with arguments.
+compiler=$CC
+
+
+# Check for command to grab the raw symbol name followed by C symbol from nm.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking command to parse $NM output from $compiler object" >&5
+$as_echo_n "checking command to parse $NM output from $compiler object... " >&6; }
+if ${lt_cv_sys_global_symbol_pipe+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+# These are sane defaults that work on at least a few old systems.
+# [They come from Ultrix.  What could be older than Ultrix?!! ;)]
+
+# Character class describing NM global symbol codes.
+symcode='[BCDEGRST]'
+
+# Regexp to match symbols that can be accessed directly from C.
+sympat='\([_A-Za-z][_A-Za-z0-9]*\)'
+
+# Define system-specific variables.
+case $host_os in
+aix*)
+  symcode='[BCDT]'
+  ;;
+cygwin* | mingw* | pw32* | cegcc*)
+  symcode='[ABCDGISTW]'
+  ;;
+hpux*)
+  if test ia64 = "$host_cpu"; then
+    symcode='[ABCDEGRST]'
+  fi
+  ;;
+irix* | nonstopux*)
+  symcode='[BCDEGRST]'
+  ;;
+osf*)
+  symcode='[BCDEGQRST]'
+  ;;
+solaris*)
+  symcode='[BDRT]'
+  ;;
+sco3.2v5*)
+  symcode='[DT]'
+  ;;
+sysv4.2uw2*)
+  symcode='[DT]'
+  ;;
+sysv5* | sco5v6* | unixware* | OpenUNIX*)
+  symcode='[ABDT]'
+  ;;
+sysv4)
+  symcode='[DFNSTU]'
+  ;;
+esac
+
+# If we're using GNU nm, then use its standard symbol codes.
+case `$NM -V 2>&1` in
+*GNU* | *'with BFD'*)
+  symcode='[ABCDGIRSTW]' ;;
+esac
+
+if test "$lt_cv_nm_interface" = "MS dumpbin"; then
+  # Gets list of data symbols to import.
+  lt_cv_sys_global_symbol_to_import="sed -n -e 's/^I .* \(.*\)$/\1/p'"
+  # Adjust the below global symbol transforms to fixup imported variables.
+  lt_cdecl_hook=" -e 's/^I .* \(.*\)$/extern __declspec(dllimport) char \1;/p'"
+  lt_c_name_hook=" -e 's/^I .* \(.*\)$/  {\"\1\", (void *) 0},/p'"
+  lt_c_name_lib_hook="\
+  -e 's/^I .* \(lib.*\)$/  {\"\1\", (void *) 0},/p'\
+  -e 's/^I .* \(.*\)$/  {\"lib\1\", (void *) 0},/p'"
+else
+  # Disable hooks by default.
+  lt_cv_sys_global_symbol_to_import=
+  lt_cdecl_hook=
+  lt_c_name_hook=
+  lt_c_name_lib_hook=
+fi
+
+# Transform an extracted symbol line into a proper C declaration.
+# Some systems (esp. on ia64) link data and code symbols differently,
+# so use this general approach.
+lt_cv_sys_global_symbol_to_cdecl="sed -n"\
+$lt_cdecl_hook\
+" -e 's/^T .* \(.*\)$/extern int \1();/p'"\
+" -e 's/^$symcode$symcode* .* \(.*\)$/extern char \1;/p'"
+
+# Transform an extracted symbol line into symbol name and symbol address
+lt_cv_sys_global_symbol_to_c_name_address="sed -n"\
+$lt_c_name_hook\
+" -e 's/^: \(.*\) .*$/  {\"\1\", (void *) 0},/p'"\
+" -e 's/^$symcode$symcode* .* \(.*\)$/  {\"\1\", (void *) \&\1},/p'"
+
+# Transform an extracted symbol line into symbol name with lib prefix and
+# symbol address.
+lt_cv_sys_global_symbol_to_c_name_address_lib_prefix="sed -n"\
+$lt_c_name_lib_hook\
+" -e 's/^: \(.*\) .*$/  {\"\1\", (void *) 0},/p'"\
+" -e 's/^$symcode$symcode* .* \(lib.*\)$/  {\"\1\", (void *) \&\1},/p'"\
+" -e 's/^$symcode$symcode* .* \(.*\)$/  {\"lib\1\", (void *) \&\1},/p'"
+
+# Handle CRLF in mingw tool chain
+opt_cr=
+case $build_os in
+mingw*)
+  opt_cr=`$ECHO 'x\{0,1\}' | tr x '\015'` # option cr in regexp
+  ;;
+esac
+
+# Try without a prefix underscore, then with it.
+for ac_symprfx in "" "_"; do
+
+  # Transform symcode, sympat, and symprfx into a raw symbol and a C symbol.
+  symxfrm="\\1 $ac_symprfx\\2 \\2"
+
+  # Write the raw and C identifiers.
+  if test "$lt_cv_nm_interface" = "MS dumpbin"; then
+    # Fake it for dumpbin and say T for any non-static function,
+    # D for any global variable and I for any imported variable.
+    # Also find C++ and __fastcall symbols from MSVC++,
+    # which start with @ or ?.
+    lt_cv_sys_global_symbol_pipe="$AWK '"\
+"     {last_section=section; section=\$ 3};"\
+"     /^COFF SYMBOL TABLE/{for(i in hide) delete hide[i]};"\
+"     /Section length .*#relocs.*(pick any)/{hide[last_section]=1};"\
+"     /^ *Symbol name *: /{split(\$ 0,sn,\":\"); si=substr(sn[2],2)};"\
+"     /^ *Type *: code/{print \"T\",si,substr(si,length(prfx))};"\
+"     /^ *Type *: data/{print \"I\",si,substr(si,length(prfx))};"\
+"     \$ 0!~/External *\|/{next};"\
+"     / 0+ UNDEF /{next}; / UNDEF \([^|]\)*()/{next};"\
+"     {if(hide[section]) next};"\
+"     {f=\"D\"}; \$ 0~/\(\).*\|/{f=\"T\"};"\
+"     {split(\$ 0,a,/\||\r/); split(a[2],s)};"\
+"     s[1]~/^[@?]/{print f,s[1],s[1]; next};"\
+"     s[1]~prfx {split(s[1],t,\"@\"); print f,t[1],substr(t[1],length(prfx))}"\
+"     ' prfx=^$ac_symprfx"
+  else
+    lt_cv_sys_global_symbol_pipe="sed -n -e 's/^.*[	 ]\($symcode$symcode*\)[	 ][	 ]*$ac_symprfx$sympat$opt_cr$/$symxfrm/p'"
+  fi
+  lt_cv_sys_global_symbol_pipe="$lt_cv_sys_global_symbol_pipe | sed '/ __gnu_lto/d'"
+
+  # Check to see that the pipe works correctly.
+  pipe_works=no
+
+  rm -f conftest*
+  cat > conftest.$ac_ext <<_LT_EOF
+#ifdef __cplusplus
+extern "C" {
+#endif
+char nm_test_var;
+void nm_test_func(void);
+void nm_test_func(void){}
+#ifdef __cplusplus
+}
+#endif
+int main(){nm_test_var='a';nm_test_func();return(0);}
+_LT_EOF
+
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    # Now try to grab the symbols.
+    nlist=conftest.nm
+    if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$NM conftest.$ac_objext \| "$lt_cv_sys_global_symbol_pipe" \> $nlist\""; } >&5
+  (eval $NM conftest.$ac_objext \| "$lt_cv_sys_global_symbol_pipe" \> $nlist) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && test -s "$nlist"; then
+      # Try sorting and uniquifying the output.
+      if sort "$nlist" | uniq > "$nlist"T; then
+	mv -f "$nlist"T "$nlist"
+      else
+	rm -f "$nlist"T
+      fi
+
+      # Make sure that we snagged all the symbols we need.
+      if $GREP ' nm_test_var$' "$nlist" >/dev/null; then
+	if $GREP ' nm_test_func$' "$nlist" >/dev/null; then
+	  cat <<_LT_EOF > conftest.$ac_ext
+/* Keep this code in sync between libtool.m4, ltmain, lt_system.h, and tests.  */
+#if defined _WIN32 || defined __CYGWIN__ || defined _WIN32_WCE
+/* DATA imports from DLLs on WIN32 can't be const, because runtime
+   relocations are performed -- see ld's documentation on pseudo-relocs.  */
+# define LT_DLSYM_CONST
+#elif defined __osf__
+/* This system does not cope well with relocations in const data.  */
+# define LT_DLSYM_CONST
+#else
+# define LT_DLSYM_CONST const
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+_LT_EOF
+	  # Now generate the symbol file.
+	  eval "$lt_cv_sys_global_symbol_to_cdecl"' < "$nlist" | $GREP -v main >> conftest.$ac_ext'
+
+	  cat <<_LT_EOF >> conftest.$ac_ext
+
+/* The mapping between symbol names and symbols.  */
+LT_DLSYM_CONST struct {
+  const char *name;
+  void       *address;
+}
+lt__PROGRAM__LTX_preloaded_symbols[] =
+{
+  { "@PROGRAM@", (void *) 0 },
+_LT_EOF
+	  $SED "s/^$symcode$symcode* .* \(.*\)$/  {\"\1\", (void *) \&\1},/" < "$nlist" | $GREP -v main >> conftest.$ac_ext
+	  cat <<\_LT_EOF >> conftest.$ac_ext
+  {0, (void *) 0}
+};
+
+/* This works around a problem in FreeBSD linker */
+#ifdef FREEBSD_WORKAROUND
+static const void *lt_preloaded_setup() {
+  return lt__PROGRAM__LTX_preloaded_symbols;
+}
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+_LT_EOF
+	  # Now try linking the two files.
+	  mv conftest.$ac_objext conftstm.$ac_objext
+	  lt_globsym_save_LIBS=$LIBS
+	  lt_globsym_save_CFLAGS=$CFLAGS
+	  LIBS=conftstm.$ac_objext
+	  CFLAGS="$CFLAGS$lt_prog_compiler_no_builtin_flag"
+	  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_link\""; } >&5
+  (eval $ac_link) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && test -s conftest$ac_exeext; then
+	    pipe_works=yes
+	  fi
+	  LIBS=$lt_globsym_save_LIBS
+	  CFLAGS=$lt_globsym_save_CFLAGS
+	else
+	  echo "cannot find nm_test_func in $nlist" >&5
+	fi
+      else
+	echo "cannot find nm_test_var in $nlist" >&5
+      fi
+    else
+      echo "cannot run $lt_cv_sys_global_symbol_pipe" >&5
+    fi
+  else
+    echo "$progname: failed program was:" >&5
+    cat conftest.$ac_ext >&5
+  fi
+  rm -rf conftest* conftst*
+
+  # Do not use the global_symbol_pipe unless it works.
+  if test yes = "$pipe_works"; then
+    break
+  else
+    lt_cv_sys_global_symbol_pipe=
+  fi
+done
+
+fi
+
+if test -z "$lt_cv_sys_global_symbol_pipe"; then
+  lt_cv_sys_global_symbol_to_cdecl=
+fi
+if test -z "$lt_cv_sys_global_symbol_pipe$lt_cv_sys_global_symbol_to_cdecl"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: failed" >&5
+$as_echo "failed" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: ok" >&5
+$as_echo "ok" >&6; }
+fi
+
+# Response file support.
+if test "$lt_cv_nm_interface" = "MS dumpbin"; then
+  nm_file_list_spec='@'
+elif $NM --help 2>/dev/null | grep '[@]FILE' >/dev/null; then
+  nm_file_list_spec='@'
+fi
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for sysroot" >&5
+$as_echo_n "checking for sysroot... " >&6; }
+
+# Check whether --with-sysroot was given.
+if test "${with_sysroot+set}" = set; then :
+  withval=$with_sysroot;
+else
+  with_sysroot=no
+fi
+
+
+lt_sysroot=
+case $with_sysroot in #(
+ yes)
+   if test yes = "$GCC"; then
+     lt_sysroot=`$CC --print-sysroot 2>/dev/null`
+   fi
+   ;; #(
+ /*)
+   lt_sysroot=`echo "$with_sysroot" | sed -e "$sed_quote_subst"`
+   ;; #(
+ no|'')
+   ;; #(
+ *)
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_sysroot" >&5
+$as_echo "$with_sysroot" >&6; }
+   as_fn_error $? "The sysroot must be an absolute path." "$LINENO" 5
+   ;;
+esac
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: ${lt_sysroot:-no}" >&5
+$as_echo "${lt_sysroot:-no}" >&6; }
+
+
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for a working dd" >&5
+$as_echo_n "checking for a working dd... " >&6; }
+if ${ac_cv_path_lt_DD+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  printf 0123456789abcdef0123456789abcdef >conftest.i
+cat conftest.i conftest.i >conftest2.i
+: ${lt_DD:=$DD}
+if test -z "$lt_DD"; then
+  ac_path_lt_DD_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in dd; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_lt_DD="$as_dir/$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_lt_DD" || continue
+if "$ac_path_lt_DD" bs=32 count=1 <conftest2.i >conftest.out 2>/dev/null; then
+  cmp -s conftest.i conftest.out \
+  && ac_cv_path_lt_DD="$ac_path_lt_DD" ac_path_lt_DD_found=:
+fi
+      $ac_path_lt_DD_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_lt_DD"; then
+    :
+  fi
+else
+  ac_cv_path_lt_DD=$lt_DD
+fi
+
+rm -f conftest.i conftest2.i conftest.out
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_lt_DD" >&5
+$as_echo "$ac_cv_path_lt_DD" >&6; }
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking how to truncate binary pipes" >&5
+$as_echo_n "checking how to truncate binary pipes... " >&6; }
+if ${lt_cv_truncate_bin+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  printf 0123456789abcdef0123456789abcdef >conftest.i
+cat conftest.i conftest.i >conftest2.i
+lt_cv_truncate_bin=
+if "$ac_cv_path_lt_DD" bs=32 count=1 <conftest2.i >conftest.out 2>/dev/null; then
+  cmp -s conftest.i conftest.out \
+  && lt_cv_truncate_bin="$ac_cv_path_lt_DD bs=4096 count=1"
+fi
+rm -f conftest.i conftest2.i conftest.out
+test -z "$lt_cv_truncate_bin" && lt_cv_truncate_bin="$SED -e 4q"
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_truncate_bin" >&5
+$as_echo "$lt_cv_truncate_bin" >&6; }
+
+
+
+
+
+
+
+# Calculate cc_basename.  Skip known compiler wrappers and cross-prefix.
+func_cc_basename ()
+{
+    for cc_temp in $*""; do
+      case $cc_temp in
+        compile | *[\\/]compile | ccache | *[\\/]ccache ) ;;
+        distcc | *[\\/]distcc | purify | *[\\/]purify ) ;;
+        \-*) ;;
+        *) break;;
+      esac
+    done
+    func_cc_basename_result=`$ECHO "$cc_temp" | $SED "s%.*/%%; s%^$host_alias-%%"`
+}
+
+# Check whether --enable-libtool-lock was given.
+if test "${enable_libtool_lock+set}" = set; then :
+  enableval=$enable_libtool_lock;
+fi
+
+test no = "$enable_libtool_lock" || enable_libtool_lock=yes
+
+# Some flags need to be propagated to the compiler or linker for good
+# libtool support.
+case $host in
+ia64-*-hpux*)
+  # Find out what ABI is being produced by ac_compile, and set mode
+  # options accordingly.
+  echo 'int i;' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    case `/usr/bin/file conftest.$ac_objext` in
+      *ELF-32*)
+	HPUX_IA64_MODE=32
+	;;
+      *ELF-64*)
+	HPUX_IA64_MODE=64
+	;;
+    esac
+  fi
+  rm -rf conftest*
+  ;;
+*-*-irix6*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.
+  echo '#line '$LINENO' "configure"' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    if test yes = "$lt_cv_prog_gnu_ld"; then
+      case `/usr/bin/file conftest.$ac_objext` in
+	*32-bit*)
+	  LD="${LD-ld} -melf32bsmip"
+	  ;;
+	*N32*)
+	  LD="${LD-ld} -melf32bmipn32"
+	  ;;
+	*64-bit*)
+	  LD="${LD-ld} -melf64bmip"
+	;;
+      esac
+    else
+      case `/usr/bin/file conftest.$ac_objext` in
+	*32-bit*)
+	  LD="${LD-ld} -32"
+	  ;;
+	*N32*)
+	  LD="${LD-ld} -n32"
+	  ;;
+	*64-bit*)
+	  LD="${LD-ld} -64"
+	  ;;
+      esac
+    fi
+  fi
+  rm -rf conftest*
+  ;;
+
+mips64*-*linux*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.
+  echo '#line '$LINENO' "configure"' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    emul=elf
+    case `/usr/bin/file conftest.$ac_objext` in
+      *32-bit*)
+	emul="${emul}32"
+	;;
+      *64-bit*)
+	emul="${emul}64"
+	;;
+    esac
+    case `/usr/bin/file conftest.$ac_objext` in
+      *MSB*)
+	emul="${emul}btsmip"
+	;;
+      *LSB*)
+	emul="${emul}ltsmip"
+	;;
+    esac
+    case `/usr/bin/file conftest.$ac_objext` in
+      *N32*)
+	emul="${emul}n32"
+	;;
+    esac
+    LD="${LD-ld} -m $emul"
+  fi
+  rm -rf conftest*
+  ;;
+
+x86_64-*kfreebsd*-gnu|x86_64-*linux*|powerpc*-*linux*| \
+s390*-*linux*|s390*-*tpf*|sparc*-*linux*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.  Note that the listed cases only cover the
+  # situations where additional linker options are needed (such as when
+  # doing 32-bit compilation for a host where ld defaults to 64-bit, or
+  # vice versa); the common cases where no linker options are needed do
+  # not appear in the list.
+  echo 'int i;' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    case `/usr/bin/file conftest.o` in
+      *32-bit*)
+	case $host in
+	  x86_64-*kfreebsd*-gnu)
+	    LD="${LD-ld} -m elf_i386_fbsd"
+	    ;;
+	  x86_64-*linux*)
+	    case `/usr/bin/file conftest.o` in
+	      *x86-64*)
+		LD="${LD-ld} -m elf32_x86_64"
+		;;
+	      *)
+		LD="${LD-ld} -m elf_i386"
+		;;
+	    esac
+	    ;;
+	  powerpc64le-*linux*)
+	    LD="${LD-ld} -m elf32lppclinux"
+	    ;;
+	  powerpc64-*linux*)
+	    LD="${LD-ld} -m elf32ppclinux"
+	    ;;
+	  s390x-*linux*)
+	    LD="${LD-ld} -m elf_s390"
+	    ;;
+	  sparc64-*linux*)
+	    LD="${LD-ld} -m elf32_sparc"
+	    ;;
+	esac
+	;;
+      *64-bit*)
+	case $host in
+	  x86_64-*kfreebsd*-gnu)
+	    LD="${LD-ld} -m elf_x86_64_fbsd"
+	    ;;
+	  x86_64-*linux*)
+	    LD="${LD-ld} -m elf_x86_64"
+	    ;;
+	  powerpcle-*linux*)
+	    LD="${LD-ld} -m elf64lppc"
+	    ;;
+	  powerpc-*linux*)
+	    LD="${LD-ld} -m elf64ppc"
+	    ;;
+	  s390*-*linux*|s390*-*tpf*)
+	    LD="${LD-ld} -m elf64_s390"
+	    ;;
+	  sparc*-*linux*)
+	    LD="${LD-ld} -m elf64_sparc"
+	    ;;
+	esac
+	;;
+    esac
+  fi
+  rm -rf conftest*
+  ;;
+
+*-*-sco3.2v5*)
+  # On SCO OpenServer 5, we need -belf to get full-featured binaries.
+  SAVE_CFLAGS=$CFLAGS
+  CFLAGS="$CFLAGS -belf"
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the C compiler needs -belf" >&5
+$as_echo_n "checking whether the C compiler needs -belf... " >&6; }
+if ${lt_cv_cc_needs_belf+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  lt_cv_cc_needs_belf=yes
+else
+  lt_cv_cc_needs_belf=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+     ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_cc_needs_belf" >&5
+$as_echo "$lt_cv_cc_needs_belf" >&6; }
+  if test yes != "$lt_cv_cc_needs_belf"; then
+    # this is probably gcc 2.8.0, egcs 1.0 or newer; no need for -belf
+    CFLAGS=$SAVE_CFLAGS
+  fi
+  ;;
+*-*solaris*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.
+  echo 'int i;' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    case `/usr/bin/file conftest.o` in
+    *64-bit*)
+      case $lt_cv_prog_gnu_ld in
+      yes*)
+        case $host in
+        i?86-*-solaris*|x86_64-*-solaris*)
+          LD="${LD-ld} -m elf_x86_64"
+          ;;
+        sparc*-*-solaris*)
+          LD="${LD-ld} -m elf64_sparc"
+          ;;
+        esac
+        # GNU ld 2.21 introduced _sol2 emulations.  Use them if available.
+        if ${LD-ld} -V | grep _sol2 >/dev/null 2>&1; then
+          LD=${LD-ld}_sol2
+        fi
+        ;;
+      *)
+	if ${LD-ld} -64 -r -o conftest2.o conftest.o >/dev/null 2>&1; then
+	  LD="${LD-ld} -64"
+	fi
+	;;
+      esac
+      ;;
+    esac
+  fi
+  rm -rf conftest*
+  ;;
+esac
+
+need_locks=$enable_libtool_lock
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}mt", so it can be a program name with args.
+set dummy ${ac_tool_prefix}mt; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_MANIFEST_TOOL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$MANIFEST_TOOL"; then
+  ac_cv_prog_MANIFEST_TOOL="$MANIFEST_TOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_MANIFEST_TOOL="${ac_tool_prefix}mt"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+MANIFEST_TOOL=$ac_cv_prog_MANIFEST_TOOL
+if test -n "$MANIFEST_TOOL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $MANIFEST_TOOL" >&5
+$as_echo "$MANIFEST_TOOL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_MANIFEST_TOOL"; then
+  ac_ct_MANIFEST_TOOL=$MANIFEST_TOOL
+  # Extract the first word of "mt", so it can be a program name with args.
+set dummy mt; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_MANIFEST_TOOL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_MANIFEST_TOOL"; then
+  ac_cv_prog_ac_ct_MANIFEST_TOOL="$ac_ct_MANIFEST_TOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_MANIFEST_TOOL="mt"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_MANIFEST_TOOL=$ac_cv_prog_ac_ct_MANIFEST_TOOL
+if test -n "$ac_ct_MANIFEST_TOOL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_MANIFEST_TOOL" >&5
+$as_echo "$ac_ct_MANIFEST_TOOL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_MANIFEST_TOOL" = x; then
+    MANIFEST_TOOL=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    MANIFEST_TOOL=$ac_ct_MANIFEST_TOOL
+  fi
+else
+  MANIFEST_TOOL="$ac_cv_prog_MANIFEST_TOOL"
+fi
+
+test -z "$MANIFEST_TOOL" && MANIFEST_TOOL=mt
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if $MANIFEST_TOOL is a manifest tool" >&5
+$as_echo_n "checking if $MANIFEST_TOOL is a manifest tool... " >&6; }
+if ${lt_cv_path_mainfest_tool+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_path_mainfest_tool=no
+  echo "$as_me:$LINENO: $MANIFEST_TOOL '-?'" >&5
+  $MANIFEST_TOOL '-?' 2>conftest.err > conftest.out
+  cat conftest.err >&5
+  if $GREP 'Manifest Tool' conftest.out > /dev/null; then
+    lt_cv_path_mainfest_tool=yes
+  fi
+  rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_path_mainfest_tool" >&5
+$as_echo "$lt_cv_path_mainfest_tool" >&6; }
+if test yes != "$lt_cv_path_mainfest_tool"; then
+  MANIFEST_TOOL=:
+fi
+
+
+
+
+
+
+  case $host_os in
+    rhapsody* | darwin*)
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}dsymutil", so it can be a program name with args.
+set dummy ${ac_tool_prefix}dsymutil; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_DSYMUTIL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$DSYMUTIL"; then
+  ac_cv_prog_DSYMUTIL="$DSYMUTIL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_DSYMUTIL="${ac_tool_prefix}dsymutil"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+DSYMUTIL=$ac_cv_prog_DSYMUTIL
+if test -n "$DSYMUTIL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $DSYMUTIL" >&5
+$as_echo "$DSYMUTIL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_DSYMUTIL"; then
+  ac_ct_DSYMUTIL=$DSYMUTIL
+  # Extract the first word of "dsymutil", so it can be a program name with args.
+set dummy dsymutil; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_DSYMUTIL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_DSYMUTIL"; then
+  ac_cv_prog_ac_ct_DSYMUTIL="$ac_ct_DSYMUTIL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_DSYMUTIL="dsymutil"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_DSYMUTIL=$ac_cv_prog_ac_ct_DSYMUTIL
+if test -n "$ac_ct_DSYMUTIL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_DSYMUTIL" >&5
+$as_echo "$ac_ct_DSYMUTIL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_DSYMUTIL" = x; then
+    DSYMUTIL=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    DSYMUTIL=$ac_ct_DSYMUTIL
+  fi
+else
+  DSYMUTIL="$ac_cv_prog_DSYMUTIL"
+fi
+
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}nmedit", so it can be a program name with args.
+set dummy ${ac_tool_prefix}nmedit; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_NMEDIT+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$NMEDIT"; then
+  ac_cv_prog_NMEDIT="$NMEDIT" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_NMEDIT="${ac_tool_prefix}nmedit"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+NMEDIT=$ac_cv_prog_NMEDIT
+if test -n "$NMEDIT"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $NMEDIT" >&5
+$as_echo "$NMEDIT" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_NMEDIT"; then
+  ac_ct_NMEDIT=$NMEDIT
+  # Extract the first word of "nmedit", so it can be a program name with args.
+set dummy nmedit; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_NMEDIT+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_NMEDIT"; then
+  ac_cv_prog_ac_ct_NMEDIT="$ac_ct_NMEDIT" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_NMEDIT="nmedit"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_NMEDIT=$ac_cv_prog_ac_ct_NMEDIT
+if test -n "$ac_ct_NMEDIT"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_NMEDIT" >&5
+$as_echo "$ac_ct_NMEDIT" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_NMEDIT" = x; then
+    NMEDIT=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    NMEDIT=$ac_ct_NMEDIT
+  fi
+else
+  NMEDIT="$ac_cv_prog_NMEDIT"
+fi
+
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}lipo", so it can be a program name with args.
+set dummy ${ac_tool_prefix}lipo; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_LIPO+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$LIPO"; then
+  ac_cv_prog_LIPO="$LIPO" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_LIPO="${ac_tool_prefix}lipo"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+LIPO=$ac_cv_prog_LIPO
+if test -n "$LIPO"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $LIPO" >&5
+$as_echo "$LIPO" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_LIPO"; then
+  ac_ct_LIPO=$LIPO
+  # Extract the first word of "lipo", so it can be a program name with args.
+set dummy lipo; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_LIPO+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_LIPO"; then
+  ac_cv_prog_ac_ct_LIPO="$ac_ct_LIPO" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_LIPO="lipo"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_LIPO=$ac_cv_prog_ac_ct_LIPO
+if test -n "$ac_ct_LIPO"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_LIPO" >&5
+$as_echo "$ac_ct_LIPO" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_LIPO" = x; then
+    LIPO=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    LIPO=$ac_ct_LIPO
+  fi
+else
+  LIPO="$ac_cv_prog_LIPO"
+fi
+
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}otool", so it can be a program name with args.
+set dummy ${ac_tool_prefix}otool; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_OTOOL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$OTOOL"; then
+  ac_cv_prog_OTOOL="$OTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_OTOOL="${ac_tool_prefix}otool"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+OTOOL=$ac_cv_prog_OTOOL
+if test -n "$OTOOL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $OTOOL" >&5
+$as_echo "$OTOOL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_OTOOL"; then
+  ac_ct_OTOOL=$OTOOL
+  # Extract the first word of "otool", so it can be a program name with args.
+set dummy otool; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_OTOOL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_OTOOL"; then
+  ac_cv_prog_ac_ct_OTOOL="$ac_ct_OTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_OTOOL="otool"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_OTOOL=$ac_cv_prog_ac_ct_OTOOL
+if test -n "$ac_ct_OTOOL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_OTOOL" >&5
+$as_echo "$ac_ct_OTOOL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_OTOOL" = x; then
+    OTOOL=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    OTOOL=$ac_ct_OTOOL
+  fi
+else
+  OTOOL="$ac_cv_prog_OTOOL"
+fi
+
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}otool64", so it can be a program name with args.
+set dummy ${ac_tool_prefix}otool64; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_OTOOL64+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$OTOOL64"; then
+  ac_cv_prog_OTOOL64="$OTOOL64" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_OTOOL64="${ac_tool_prefix}otool64"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+OTOOL64=$ac_cv_prog_OTOOL64
+if test -n "$OTOOL64"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $OTOOL64" >&5
+$as_echo "$OTOOL64" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_OTOOL64"; then
+  ac_ct_OTOOL64=$OTOOL64
+  # Extract the first word of "otool64", so it can be a program name with args.
+set dummy otool64; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_OTOOL64+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_OTOOL64"; then
+  ac_cv_prog_ac_ct_OTOOL64="$ac_ct_OTOOL64" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_OTOOL64="otool64"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_OTOOL64=$ac_cv_prog_ac_ct_OTOOL64
+if test -n "$ac_ct_OTOOL64"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_OTOOL64" >&5
+$as_echo "$ac_ct_OTOOL64" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_OTOOL64" = x; then
+    OTOOL64=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    OTOOL64=$ac_ct_OTOOL64
+  fi
+else
+  OTOOL64="$ac_cv_prog_OTOOL64"
+fi
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -single_module linker flag" >&5
+$as_echo_n "checking for -single_module linker flag... " >&6; }
+if ${lt_cv_apple_cc_single_mod+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_apple_cc_single_mod=no
+      if test -z "$LT_MULTI_MODULE"; then
+	# By default we will add the -single_module flag. You can override
+	# by either setting the environment variable LT_MULTI_MODULE
+	# non-empty at configure time, or by adding -multi_module to the
+	# link flags.
+	rm -rf libconftest.dylib*
+	echo "int foo(void){return 1;}" > conftest.c
+	echo "$LTCC $LTCFLAGS $LDFLAGS -o libconftest.dylib \
+-dynamiclib -Wl,-single_module conftest.c" >&5
+	$LTCC $LTCFLAGS $LDFLAGS -o libconftest.dylib \
+	  -dynamiclib -Wl,-single_module conftest.c 2>conftest.err
+        _lt_result=$?
+	# If there is a non-empty error log, and "single_module"
+	# appears in it, assume the flag caused a linker warning
+        if test -s conftest.err && $GREP single_module conftest.err; then
+	  cat conftest.err >&5
+	# Otherwise, if the output was created with a 0 exit code from
+	# the compiler, it worked.
+	elif test -f libconftest.dylib && test 0 = "$_lt_result"; then
+	  lt_cv_apple_cc_single_mod=yes
+	else
+	  cat conftest.err >&5
+	fi
+	rm -rf libconftest.dylib*
+	rm -f conftest.*
+      fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_apple_cc_single_mod" >&5
+$as_echo "$lt_cv_apple_cc_single_mod" >&6; }
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -exported_symbols_list linker flag" >&5
+$as_echo_n "checking for -exported_symbols_list linker flag... " >&6; }
+if ${lt_cv_ld_exported_symbols_list+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_ld_exported_symbols_list=no
+      save_LDFLAGS=$LDFLAGS
+      echo "_main" > conftest.sym
+      LDFLAGS="$LDFLAGS -Wl,-exported_symbols_list,conftest.sym"
+      cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  lt_cv_ld_exported_symbols_list=yes
+else
+  lt_cv_ld_exported_symbols_list=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+	LDFLAGS=$save_LDFLAGS
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_ld_exported_symbols_list" >&5
+$as_echo "$lt_cv_ld_exported_symbols_list" >&6; }
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -force_load linker flag" >&5
+$as_echo_n "checking for -force_load linker flag... " >&6; }
+if ${lt_cv_ld_force_load+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_ld_force_load=no
+      cat > conftest.c << _LT_EOF
+int forced_loaded() { return 2;}
+_LT_EOF
+      echo "$LTCC $LTCFLAGS -c -o conftest.o conftest.c" >&5
+      $LTCC $LTCFLAGS -c -o conftest.o conftest.c 2>&5
+      echo "$AR cru libconftest.a conftest.o" >&5
+      $AR cru libconftest.a conftest.o 2>&5
+      echo "$RANLIB libconftest.a" >&5
+      $RANLIB libconftest.a 2>&5
+      cat > conftest.c << _LT_EOF
+int main() { return 0;}
+_LT_EOF
+      echo "$LTCC $LTCFLAGS $LDFLAGS -o conftest conftest.c -Wl,-force_load,./libconftest.a" >&5
+      $LTCC $LTCFLAGS $LDFLAGS -o conftest conftest.c -Wl,-force_load,./libconftest.a 2>conftest.err
+      _lt_result=$?
+      if test -s conftest.err && $GREP force_load conftest.err; then
+	cat conftest.err >&5
+      elif test -f conftest && test 0 = "$_lt_result" && $GREP forced_load conftest >/dev/null 2>&1; then
+	lt_cv_ld_force_load=yes
+      else
+	cat conftest.err >&5
+      fi
+        rm -f conftest.err libconftest.a conftest conftest.c
+        rm -rf conftest.dSYM
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_ld_force_load" >&5
+$as_echo "$lt_cv_ld_force_load" >&6; }
+    case $host_os in
+    rhapsody* | darwin1.[012])
+      _lt_dar_allow_undefined='$wl-undefined ${wl}suppress' ;;
+    darwin1.*)
+      _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
+    darwin*) # darwin 5.x on
+      # if running on 10.5 or later, the deployment target defaults
+      # to the OS version, if on x86, and 10.4, the deployment
+      # target defaults to 10.4. Don't you love it?
+      case ${MACOSX_DEPLOYMENT_TARGET-10.0},$host in
+	10.0,*86*-darwin8*|10.0,*-darwin[91]*)
+	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
+	10.[012][,.]*)
+	  _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
+	10.*)
+	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
+      esac
+    ;;
+  esac
+    if test yes = "$lt_cv_apple_cc_single_mod"; then
+      _lt_dar_single_mod='$single_module'
+    fi
+    if test yes = "$lt_cv_ld_exported_symbols_list"; then
+      _lt_dar_export_syms=' $wl-exported_symbols_list,$output_objdir/$libname-symbols.expsym'
+    else
+      _lt_dar_export_syms='~$NMEDIT -s $output_objdir/$libname-symbols.expsym $lib'
+    fi
+    if test : != "$DSYMUTIL" && test no = "$lt_cv_ld_force_load"; then
+      _lt_dsymutil='~$DSYMUTIL $lib || :'
+    else
+      _lt_dsymutil=
+    fi
+    ;;
+  esac
+
+# func_munge_path_list VARIABLE PATH
+# -----------------------------------
+# VARIABLE is name of variable containing _space_ separated list of
+# directories to be munged by the contents of PATH, which is string
+# having a format:
+# "DIR[:DIR]:"
+#       string "DIR[ DIR]" will be prepended to VARIABLE
+# ":DIR[:DIR]"
+#       string "DIR[ DIR]" will be appended to VARIABLE
+# "DIRP[:DIRP]::[DIRA:]DIRA"
+#       string "DIRP[ DIRP]" will be prepended to VARIABLE and string
+#       "DIRA[ DIRA]" will be appended to VARIABLE
+# "DIR[:DIR]"
+#       VARIABLE will be replaced by "DIR[ DIR]"
+func_munge_path_list ()
+{
+    case x$2 in
+    x)
+        ;;
+    *:)
+        eval $1=\"`$ECHO $2 | $SED 's/:/ /g'` \$$1\"
+        ;;
+    x:*)
+        eval $1=\"\$$1 `$ECHO $2 | $SED 's/:/ /g'`\"
+        ;;
+    *::*)
+        eval $1=\"\$$1\ `$ECHO $2 | $SED -e 's/.*:://' -e 's/:/ /g'`\"
+        eval $1=\"`$ECHO $2 | $SED -e 's/::.*//' -e 's/:/ /g'`\ \$$1\"
+        ;;
+    *)
+        eval $1=\"`$ECHO $2 | $SED 's/:/ /g'`\"
+        ;;
+    esac
+}
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ANSI C header files" >&5
+$as_echo_n "checking for ANSI C header files... " >&6; }
+if ${ac_cv_header_stdc+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <float.h>
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_header_stdc=yes
+else
+  ac_cv_header_stdc=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+if test $ac_cv_header_stdc = yes; then
+  # SunOS 4.x string.h does not declare mem*, contrary to ANSI.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <string.h>
+
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP "memchr" >/dev/null 2>&1; then :
+
+else
+  ac_cv_header_stdc=no
+fi
+rm -f conftest*
+
+fi
+
+if test $ac_cv_header_stdc = yes; then
+  # ISC 2.0.2 stdlib.h does not declare free, contrary to ANSI.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdlib.h>
+
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP "free" >/dev/null 2>&1; then :
+
+else
+  ac_cv_header_stdc=no
+fi
+rm -f conftest*
+
+fi
+
+if test $ac_cv_header_stdc = yes; then
+  # /bin/cc in Irix-4.0.5 gets non-ANSI ctype macros unless using -ansi.
+  if test "$cross_compiling" = yes; then :
+  :
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <ctype.h>
+#include <stdlib.h>
+#if ((' ' & 0x0FF) == 0x020)
+# define ISLOWER(c) ('a' <= (c) && (c) <= 'z')
+# define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c))
+#else
+# define ISLOWER(c) \
+		   (('a' <= (c) && (c) <= 'i') \
+		     || ('j' <= (c) && (c) <= 'r') \
+		     || ('s' <= (c) && (c) <= 'z'))
+# define TOUPPER(c) (ISLOWER(c) ? ((c) | 0x40) : (c))
+#endif
+
+#define XOR(e, f) (((e) && !(f)) || (!(e) && (f)))
+int
+main ()
+{
+  int i;
+  for (i = 0; i < 256; i++)
+    if (XOR (islower (i), ISLOWER (i))
+	|| toupper (i) != TOUPPER (i))
+      return 2;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+
+else
+  ac_cv_header_stdc=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_header_stdc" >&5
+$as_echo "$ac_cv_header_stdc" >&6; }
+if test $ac_cv_header_stdc = yes; then
+
+$as_echo "#define STDC_HEADERS 1" >>confdefs.h
+
+fi
+
+# On IRIX 5.3, sys/types and inttypes.h are conflicting.
+for ac_header in sys/types.h sys/stat.h stdlib.h string.h memory.h strings.h \
+		  inttypes.h stdint.h unistd.h
+do :
+  as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
+ac_fn_c_check_header_compile "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default
+"
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
+  cat >>confdefs.h <<_ACEOF
+#define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
+_ACEOF
+
+fi
+
+done
+
+
+for ac_header in dlfcn.h
+do :
+  ac_fn_c_check_header_compile "$LINENO" "dlfcn.h" "ac_cv_header_dlfcn_h" "$ac_includes_default
+"
+if test "x$ac_cv_header_dlfcn_h" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_DLFCN_H 1
+_ACEOF
+
+fi
+
+done
+
+
+
+
+
+# Set options
+enable_win32_dll=yes
+
+case $host in
+*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-cegcc*)
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}as", so it can be a program name with args.
+set dummy ${ac_tool_prefix}as; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_AS+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$AS"; then
+  ac_cv_prog_AS="$AS" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AS="${ac_tool_prefix}as"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+AS=$ac_cv_prog_AS
+if test -n "$AS"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $AS" >&5
+$as_echo "$AS" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_AS"; then
+  ac_ct_AS=$AS
+  # Extract the first word of "as", so it can be a program name with args.
+set dummy as; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_AS+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_AS"; then
+  ac_cv_prog_ac_ct_AS="$ac_ct_AS" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_AS="as"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_AS=$ac_cv_prog_ac_ct_AS
+if test -n "$ac_ct_AS"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_AS" >&5
+$as_echo "$ac_ct_AS" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_AS" = x; then
+    AS="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    AS=$ac_ct_AS
+  fi
+else
+  AS="$ac_cv_prog_AS"
+fi
+
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}dlltool", so it can be a program name with args.
+set dummy ${ac_tool_prefix}dlltool; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_DLLTOOL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$DLLTOOL"; then
+  ac_cv_prog_DLLTOOL="$DLLTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_DLLTOOL="${ac_tool_prefix}dlltool"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+DLLTOOL=$ac_cv_prog_DLLTOOL
+if test -n "$DLLTOOL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $DLLTOOL" >&5
+$as_echo "$DLLTOOL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_DLLTOOL"; then
+  ac_ct_DLLTOOL=$DLLTOOL
+  # Extract the first word of "dlltool", so it can be a program name with args.
+set dummy dlltool; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_DLLTOOL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_DLLTOOL"; then
+  ac_cv_prog_ac_ct_DLLTOOL="$ac_ct_DLLTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_DLLTOOL="dlltool"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_DLLTOOL=$ac_cv_prog_ac_ct_DLLTOOL
+if test -n "$ac_ct_DLLTOOL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_DLLTOOL" >&5
+$as_echo "$ac_ct_DLLTOOL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_DLLTOOL" = x; then
+    DLLTOOL="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    DLLTOOL=$ac_ct_DLLTOOL
+  fi
+else
+  DLLTOOL="$ac_cv_prog_DLLTOOL"
+fi
+
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}objdump", so it can be a program name with args.
+set dummy ${ac_tool_prefix}objdump; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_OBJDUMP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$OBJDUMP"; then
+  ac_cv_prog_OBJDUMP="$OBJDUMP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_OBJDUMP="${ac_tool_prefix}objdump"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+OBJDUMP=$ac_cv_prog_OBJDUMP
+if test -n "$OBJDUMP"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $OBJDUMP" >&5
+$as_echo "$OBJDUMP" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_OBJDUMP"; then
+  ac_ct_OBJDUMP=$OBJDUMP
+  # Extract the first word of "objdump", so it can be a program name with args.
+set dummy objdump; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_ac_ct_OBJDUMP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$ac_ct_OBJDUMP"; then
+  ac_cv_prog_ac_ct_OBJDUMP="$ac_ct_OBJDUMP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_OBJDUMP="objdump"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_OBJDUMP=$ac_cv_prog_ac_ct_OBJDUMP
+if test -n "$ac_ct_OBJDUMP"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_OBJDUMP" >&5
+$as_echo "$ac_ct_OBJDUMP" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_ct_OBJDUMP" = x; then
+    OBJDUMP="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    OBJDUMP=$ac_ct_OBJDUMP
+  fi
+else
+  OBJDUMP="$ac_cv_prog_OBJDUMP"
+fi
+
+  ;;
+esac
+
+test -z "$AS" && AS=as
+
+
+
+
+
+test -z "$DLLTOOL" && DLLTOOL=dlltool
+
+
+
+
+
+test -z "$OBJDUMP" && OBJDUMP=objdump
+
+
+
+
+
+
+
+        enable_dlopen=no
+
+
+
+            # Check whether --enable-shared was given.
+if test "${enable_shared+set}" = set; then :
+  enableval=$enable_shared; p=${PACKAGE-default}
+    case $enableval in
+    yes) enable_shared=yes ;;
+    no) enable_shared=no ;;
+    *)
+      enable_shared=no
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for pkg in $enableval; do
+	IFS=$lt_save_ifs
+	if test "X$pkg" = "X$p"; then
+	  enable_shared=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac
+else
+  enable_shared=yes
+fi
+
+
+
+
+
+
+
+
+
+  # Check whether --enable-static was given.
+if test "${enable_static+set}" = set; then :
+  enableval=$enable_static; p=${PACKAGE-default}
+    case $enableval in
+    yes) enable_static=yes ;;
+    no) enable_static=no ;;
+    *)
+     enable_static=no
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for pkg in $enableval; do
+	IFS=$lt_save_ifs
+	if test "X$pkg" = "X$p"; then
+	  enable_static=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac
+else
+  enable_static=yes
+fi
+
+
+
+
+
+
+
+
+
+
+# Check whether --with-pic was given.
+if test "${with_pic+set}" = set; then :
+  withval=$with_pic; lt_p=${PACKAGE-default}
+    case $withval in
+    yes|no) pic_mode=$withval ;;
+    *)
+      pic_mode=default
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for lt_pkg in $withval; do
+	IFS=$lt_save_ifs
+	if test "X$lt_pkg" = "X$lt_p"; then
+	  pic_mode=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac
+else
+  pic_mode=default
+fi
+
+
+
+
+
+
+
+
+  # Check whether --enable-fast-install was given.
+if test "${enable_fast_install+set}" = set; then :
+  enableval=$enable_fast_install; p=${PACKAGE-default}
+    case $enableval in
+    yes) enable_fast_install=yes ;;
+    no) enable_fast_install=no ;;
+    *)
+      enable_fast_install=no
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for pkg in $enableval; do
+	IFS=$lt_save_ifs
+	if test "X$pkg" = "X$p"; then
+	  enable_fast_install=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac
+else
+  enable_fast_install=yes
+fi
+
+
+
+
+
+
+
+
+  shared_archive_member_spec=
+case $host,$enable_shared in
+power*-*-aix[5-9]*,yes)
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking which variant of shared library versioning to provide" >&5
+$as_echo_n "checking which variant of shared library versioning to provide... " >&6; }
+
+# Check whether --with-aix-soname was given.
+if test "${with_aix_soname+set}" = set; then :
+  withval=$with_aix_soname; case $withval in
+    aix|svr4|both)
+      ;;
+    *)
+      as_fn_error $? "Unknown argument to --with-aix-soname" "$LINENO" 5
+      ;;
+    esac
+    lt_cv_with_aix_soname=$with_aix_soname
+else
+  if ${lt_cv_with_aix_soname+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_with_aix_soname=aix
+fi
+
+    with_aix_soname=$lt_cv_with_aix_soname
+fi
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_aix_soname" >&5
+$as_echo "$with_aix_soname" >&6; }
+  if test aix != "$with_aix_soname"; then
+    # For the AIX way of multilib, we name the shared archive member
+    # based on the bitwidth used, traditionally 'shr.o' or 'shr_64.o',
+    # and 'shr.imp' or 'shr_64.imp', respectively, for the Import File.
+    # Even when GNU compilers ignore OBJECT_MODE but need '-maix64' flag,
+    # the AIX toolchain works better with OBJECT_MODE set (default 32).
+    if test 64 = "${OBJECT_MODE-32}"; then
+      shared_archive_member_spec=shr_64
+    else
+      shared_archive_member_spec=shr
+    fi
+  fi
+  ;;
+*)
+  with_aix_soname=aix
+  ;;
+esac
+
+
+
+
+
+
+
+
+
+
+# This can be used to rebuild libtool when needed
+LIBTOOL_DEPS=$ltmain
+
+# Always use our own libtool.
+LIBTOOL='$(SHELL) $(top_builddir)/libtool'
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+test -z "$LN_S" && LN_S="ln -s"
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+if test -n "${ZSH_VERSION+set}"; then
+   setopt NO_GLOB_SUBST
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for objdir" >&5
+$as_echo_n "checking for objdir... " >&6; }
+if ${lt_cv_objdir+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  rm -f .libs 2>/dev/null
+mkdir .libs 2>/dev/null
+if test -d .libs; then
+  lt_cv_objdir=.libs
+else
+  # MS-DOS does not allow filenames that begin with a dot.
+  lt_cv_objdir=_libs
+fi
+rmdir .libs 2>/dev/null
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_objdir" >&5
+$as_echo "$lt_cv_objdir" >&6; }
+objdir=$lt_cv_objdir
+
+
+
+
+
+cat >>confdefs.h <<_ACEOF
+#define LT_OBJDIR "$lt_cv_objdir/"
+_ACEOF
+
+
+
+
+case $host_os in
+aix3*)
+  # AIX sometimes has problems with the GCC collect2 program.  For some
+  # reason, if we set the COLLECT_NAMES environment variable, the problems
+  # vanish in a puff of smoke.
+  if test set != "${COLLECT_NAMES+set}"; then
+    COLLECT_NAMES=
+    export COLLECT_NAMES
+  fi
+  ;;
+esac
+
+# Global variables:
+ofile=libtool
+can_build_shared=yes
+
+# All known linkers require a '.a' archive for static linking (except MSVC,
+# which needs '.lib').
+libext=a
+
+with_gnu_ld=$lt_cv_prog_gnu_ld
+
+old_CC=$CC
+old_CFLAGS=$CFLAGS
+
+# Set sane defaults for various variables
+test -z "$CC" && CC=cc
+test -z "$LTCC" && LTCC=$CC
+test -z "$LTCFLAGS" && LTCFLAGS=$CFLAGS
+test -z "$LD" && LD=ld
+test -z "$ac_objext" && ac_objext=o
+
+func_cc_basename $compiler
+cc_basename=$func_cc_basename_result
+
+
+# Only perform the check for file, if the check method requires it
+test -z "$MAGIC_CMD" && MAGIC_CMD=file
+case $deplibs_check_method in
+file_magic*)
+  if test "$file_magic_cmd" = '$MAGIC_CMD'; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ${ac_tool_prefix}file" >&5
+$as_echo_n "checking for ${ac_tool_prefix}file... " >&6; }
+if ${lt_cv_path_MAGIC_CMD+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  case $MAGIC_CMD in
+[\\/*] |  ?:[\\/]*)
+  lt_cv_path_MAGIC_CMD=$MAGIC_CMD # Let the user override the test with a path.
+  ;;
+*)
+  lt_save_MAGIC_CMD=$MAGIC_CMD
+  lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+  ac_dummy="/usr/bin$PATH_SEPARATOR$PATH"
+  for ac_dir in $ac_dummy; do
+    IFS=$lt_save_ifs
+    test -z "$ac_dir" && ac_dir=.
+    if test -f "$ac_dir/${ac_tool_prefix}file"; then
+      lt_cv_path_MAGIC_CMD=$ac_dir/"${ac_tool_prefix}file"
+      if test -n "$file_magic_test_file"; then
+	case $deplibs_check_method in
+	"file_magic "*)
+	  file_magic_regex=`expr "$deplibs_check_method" : "file_magic \(.*\)"`
+	  MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+	  if eval $file_magic_cmd \$file_magic_test_file 2> /dev/null |
+	    $EGREP "$file_magic_regex" > /dev/null; then
+	    :
+	  else
+	    cat <<_LT_EOF 1>&2
+
+*** Warning: the command libtool uses to detect shared libraries,
+*** $file_magic_cmd, produces output that libtool cannot recognize.
+*** The result is that libtool may fail to recognize shared libraries
+*** as such.  This will affect the creation of libtool libraries that
+*** depend on shared libraries, but programs linked with such libtool
+*** libraries will work regardless of this problem.  Nevertheless, you
+*** may want to report the problem to your system manager and/or to
+*** bug-libtool@gnu.org
+
+_LT_EOF
+	  fi ;;
+	esac
+      fi
+      break
+    fi
+  done
+  IFS=$lt_save_ifs
+  MAGIC_CMD=$lt_save_MAGIC_CMD
+  ;;
+esac
+fi
+
+MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+if test -n "$MAGIC_CMD"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $MAGIC_CMD" >&5
+$as_echo "$MAGIC_CMD" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+
+
+
+if test -z "$lt_cv_path_MAGIC_CMD"; then
+  if test -n "$ac_tool_prefix"; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for file" >&5
+$as_echo_n "checking for file... " >&6; }
+if ${lt_cv_path_MAGIC_CMD+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  case $MAGIC_CMD in
+[\\/*] |  ?:[\\/]*)
+  lt_cv_path_MAGIC_CMD=$MAGIC_CMD # Let the user override the test with a path.
+  ;;
+*)
+  lt_save_MAGIC_CMD=$MAGIC_CMD
+  lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+  ac_dummy="/usr/bin$PATH_SEPARATOR$PATH"
+  for ac_dir in $ac_dummy; do
+    IFS=$lt_save_ifs
+    test -z "$ac_dir" && ac_dir=.
+    if test -f "$ac_dir/file"; then
+      lt_cv_path_MAGIC_CMD=$ac_dir/"file"
+      if test -n "$file_magic_test_file"; then
+	case $deplibs_check_method in
+	"file_magic "*)
+	  file_magic_regex=`expr "$deplibs_check_method" : "file_magic \(.*\)"`
+	  MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+	  if eval $file_magic_cmd \$file_magic_test_file 2> /dev/null |
+	    $EGREP "$file_magic_regex" > /dev/null; then
+	    :
+	  else
+	    cat <<_LT_EOF 1>&2
+
+*** Warning: the command libtool uses to detect shared libraries,
+*** $file_magic_cmd, produces output that libtool cannot recognize.
+*** The result is that libtool may fail to recognize shared libraries
+*** as such.  This will affect the creation of libtool libraries that
+*** depend on shared libraries, but programs linked with such libtool
+*** libraries will work regardless of this problem.  Nevertheless, you
+*** may want to report the problem to your system manager and/or to
+*** bug-libtool@gnu.org
+
+_LT_EOF
+	  fi ;;
+	esac
+      fi
+      break
+    fi
+  done
+  IFS=$lt_save_ifs
+  MAGIC_CMD=$lt_save_MAGIC_CMD
+  ;;
+esac
+fi
+
+MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+if test -n "$MAGIC_CMD"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $MAGIC_CMD" >&5
+$as_echo "$MAGIC_CMD" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  else
+    MAGIC_CMD=:
+  fi
+fi
+
+  fi
+  ;;
+esac
+
+# Use C for the default configuration in the libtool script
+
+lt_save_CC=$CC
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+# Source file extension for C test sources.
+ac_ext=c
+
+# Object file extension for compiled C test sources.
+objext=o
+objext=$objext
+
+# Code to be used in simple compile tests
+lt_simple_compile_test_code="int some_variable = 0;"
+
+# Code to be used in simple link tests
+lt_simple_link_test_code='int main(){return(0);}'
+
+
+
+
+
+
+
+# If no C compiler was specified, use CC.
+LTCC=${LTCC-"$CC"}
+
+# If no C compiler flags were specified, use CFLAGS.
+LTCFLAGS=${LTCFLAGS-"$CFLAGS"}
+
+# Allow CC to be a program name with arguments.
+compiler=$CC
+
+# Save the default compiler, since it gets overwritten when the other
+# tags are being tested, and _LT_TAGVAR(compiler, []) is a NOP.
+compiler_DEFAULT=$CC
+
+# save warnings/boilerplate of simple test code
+ac_outfile=conftest.$ac_objext
+echo "$lt_simple_compile_test_code" >conftest.$ac_ext
+eval "$ac_compile" 2>&1 >/dev/null | $SED '/^$/d; /^ *+/d' >conftest.err
+_lt_compiler_boilerplate=`cat conftest.err`
+$RM conftest*
+
+ac_outfile=conftest.$ac_objext
+echo "$lt_simple_link_test_code" >conftest.$ac_ext
+eval "$ac_link" 2>&1 >/dev/null | $SED '/^$/d; /^ *+/d' >conftest.err
+_lt_linker_boilerplate=`cat conftest.err`
+$RM -r conftest*
+
+
+## CAVEAT EMPTOR:
+## There is no encapsulation within the following macros, do not change
+## the running order or otherwise move them around unless you know exactly
+## what you are doing...
+if test -n "$compiler"; then
+
+lt_prog_compiler_no_builtin_flag=
+
+if test yes = "$GCC"; then
+  case $cc_basename in
+  nvcc*)
+    lt_prog_compiler_no_builtin_flag=' -Xcompiler -fno-builtin' ;;
+  *)
+    lt_prog_compiler_no_builtin_flag=' -fno-builtin' ;;
+  esac
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if $compiler supports -fno-rtti -fno-exceptions" >&5
+$as_echo_n "checking if $compiler supports -fno-rtti -fno-exceptions... " >&6; }
+if ${lt_cv_prog_compiler_rtti_exceptions+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_prog_compiler_rtti_exceptions=no
+   ac_outfile=conftest.$ac_objext
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+   lt_compiler_flag="-fno-rtti -fno-exceptions"  ## exclude from sc_useless_quotes_in_assignment
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   # The option is referenced via a variable to avoid confusing sed.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&5)
+   (eval "$lt_compile" 2>conftest.err)
+   ac_status=$?
+   cat conftest.err >&5
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   if (exit $ac_status) && test -s "$ac_outfile"; then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings other than the usual output.
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' >conftest.exp
+     $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+     if test ! -s conftest.er2 || diff conftest.exp conftest.er2 >/dev/null; then
+       lt_cv_prog_compiler_rtti_exceptions=yes
+     fi
+   fi
+   $RM conftest*
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_rtti_exceptions" >&5
+$as_echo "$lt_cv_prog_compiler_rtti_exceptions" >&6; }
+
+if test yes = "$lt_cv_prog_compiler_rtti_exceptions"; then
+    lt_prog_compiler_no_builtin_flag="$lt_prog_compiler_no_builtin_flag -fno-rtti -fno-exceptions"
+else
+    :
+fi
+
+fi
+
+
+
+
+
+
+  lt_prog_compiler_wl=
+lt_prog_compiler_pic=
+lt_prog_compiler_static=
+
+
+  if test yes = "$GCC"; then
+    lt_prog_compiler_wl='-Wl,'
+    lt_prog_compiler_static='-static'
+
+    case $host_os in
+      aix*)
+      # All AIX code is PIC.
+      if test ia64 = "$host_cpu"; then
+	# AIX 5 now supports IA64 processor
+	lt_prog_compiler_static='-Bstatic'
+      fi
+      lt_prog_compiler_pic='-fPIC'
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            lt_prog_compiler_pic='-fPIC'
+        ;;
+      m68k)
+            # FIXME: we need at least 68020 code to build shared libraries, but
+            # adding the '-m68020' flag to GCC prevents building anything better,
+            # like '-m68040'.
+            lt_prog_compiler_pic='-m68020 -resident32 -malways-restore-a4'
+        ;;
+      esac
+      ;;
+
+    beos* | irix5* | irix6* | nonstopux* | osf3* | osf4* | osf5*)
+      # PIC is the default for these OSes.
+      ;;
+
+    mingw* | cygwin* | pw32* | os2* | cegcc*)
+      # This hack is so that the source file can tell whether it is being
+      # built for inclusion in a dll (and should export symbols for example).
+      # Although the cygwin gcc ignores -fPIC, still need this for old-style
+      # (--disable-auto-import) libraries
+      lt_prog_compiler_pic='-DDLL_EXPORT'
+      case $host_os in
+      os2*)
+	lt_prog_compiler_static='$wl-static'
+	;;
+      esac
+      ;;
+
+    darwin* | rhapsody*)
+      # PIC is the default on this platform
+      # Common symbols not allowed in MH_DYLIB files
+      lt_prog_compiler_pic='-fno-common'
+      ;;
+
+    haiku*)
+      # PIC is the default for Haiku.
+      # The "-static" flag exists, but is broken.
+      lt_prog_compiler_static=
+      ;;
+
+    hpux*)
+      # PIC is the default for 64-bit PA HP-UX, but not for 32-bit
+      # PA HP-UX.  On IA64 HP-UX, PIC is the default but the pic flag
+      # sets the default TLS model and affects inlining.
+      case $host_cpu in
+      hppa*64*)
+	# +Z the default
+	;;
+      *)
+	lt_prog_compiler_pic='-fPIC'
+	;;
+      esac
+      ;;
+
+    interix[3-9]*)
+      # Interix 3.x gcc -fpic/-fPIC options generate broken code.
+      # Instead, we relocate shared libraries at runtime.
+      ;;
+
+    msdosdjgpp*)
+      # Just because we use GCC doesn't mean we suddenly get shared libraries
+      # on systems that don't support them.
+      lt_prog_compiler_can_build_shared=no
+      enable_shared=no
+      ;;
+
+    *nto* | *qnx*)
+      # QNX uses GNU C++, but need to define -shared option too, otherwise
+      # it will coredump.
+      lt_prog_compiler_pic='-fPIC -shared'
+      ;;
+
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	lt_prog_compiler_pic=-Kconform_pic
+      fi
+      ;;
+
+    *)
+      lt_prog_compiler_pic='-fPIC'
+      ;;
+    esac
+
+    case $cc_basename in
+    nvcc*) # Cuda Compiler Driver 2.2
+      lt_prog_compiler_wl='-Xlinker '
+      if test -n "$lt_prog_compiler_pic"; then
+        lt_prog_compiler_pic="-Xcompiler $lt_prog_compiler_pic"
+      fi
+      ;;
+    esac
+  else
+    # PORTME Check for flag to pass linker flags through the system compiler.
+    case $host_os in
+    aix*)
+      lt_prog_compiler_wl='-Wl,'
+      if test ia64 = "$host_cpu"; then
+	# AIX 5 now supports IA64 processor
+	lt_prog_compiler_static='-Bstatic'
+      else
+	lt_prog_compiler_static='-bnso -bI:/lib/syscalls.exp'
+      fi
+      ;;
+
+    darwin* | rhapsody*)
+      # PIC is the default on this platform
+      # Common symbols not allowed in MH_DYLIB files
+      lt_prog_compiler_pic='-fno-common'
+      case $cc_basename in
+      nagfor*)
+        # NAG Fortran compiler
+        lt_prog_compiler_wl='-Wl,-Wl,,'
+        lt_prog_compiler_pic='-PIC'
+        lt_prog_compiler_static='-Bstatic'
+        ;;
+      esac
+      ;;
+
+    mingw* | cygwin* | pw32* | os2* | cegcc*)
+      # This hack is so that the source file can tell whether it is being
+      # built for inclusion in a dll (and should export symbols for example).
+      lt_prog_compiler_pic='-DDLL_EXPORT'
+      case $host_os in
+      os2*)
+	lt_prog_compiler_static='$wl-static'
+	;;
+      esac
+      ;;
+
+    hpux9* | hpux10* | hpux11*)
+      lt_prog_compiler_wl='-Wl,'
+      # PIC is the default for IA64 HP-UX and 64-bit HP-UX, but
+      # not for PA HP-UX.
+      case $host_cpu in
+      hppa*64*|ia64*)
+	# +Z the default
+	;;
+      *)
+	lt_prog_compiler_pic='+Z'
+	;;
+      esac
+      # Is there a better lt_prog_compiler_static that works with the bundled CC?
+      lt_prog_compiler_static='$wl-a ${wl}archive'
+      ;;
+
+    irix5* | irix6* | nonstopux*)
+      lt_prog_compiler_wl='-Wl,'
+      # PIC (with -KPIC) is the default.
+      lt_prog_compiler_static='-non_shared'
+      ;;
+
+    linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+      case $cc_basename in
+      # old Intel for x86_64, which still supported -KPIC.
+      ecc*)
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-KPIC'
+	lt_prog_compiler_static='-static'
+        ;;
+      # icc used to be incompatible with GCC.
+      # ICC 10 doesn't accept -KPIC any more.
+      icc* | ifort*)
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-fPIC'
+	lt_prog_compiler_static='-static'
+        ;;
+      # Lahey Fortran 8.1.
+      lf95*)
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='--shared'
+	lt_prog_compiler_static='--static'
+	;;
+      nagfor*)
+	# NAG Fortran compiler
+	lt_prog_compiler_wl='-Wl,-Wl,,'
+	lt_prog_compiler_pic='-PIC'
+	lt_prog_compiler_static='-Bstatic'
+	;;
+      tcc*)
+	# Fabrice Bellard et al's Tiny C Compiler
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-fPIC'
+	lt_prog_compiler_static='-static'
+	;;
+      pgcc* | pgf77* | pgf90* | pgf95* | pgfortran*)
+        # Portland Group compilers (*not* the Pentium gcc compiler,
+	# which looks to be a dead project)
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-fpic'
+	lt_prog_compiler_static='-Bstatic'
+        ;;
+      ccc*)
+        lt_prog_compiler_wl='-Wl,'
+        # All Alpha code is PIC.
+        lt_prog_compiler_static='-non_shared'
+        ;;
+      xl* | bgxl* | bgf* | mpixl*)
+	# IBM XL C 8.0/Fortran 10.1, 11.1 on PPC and BlueGene
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-qpic'
+	lt_prog_compiler_static='-qstaticlink'
+	;;
+      *)
+	case `$CC -V 2>&1 | sed 5q` in
+	*Sun\ Ceres\ Fortran* | *Sun*Fortran*\ [1-7].* | *Sun*Fortran*\ 8.[0-3]*)
+	  # Sun Fortran 8.3 passes all unrecognized flags to the linker
+	  lt_prog_compiler_pic='-KPIC'
+	  lt_prog_compiler_static='-Bstatic'
+	  lt_prog_compiler_wl=''
+	  ;;
+	*Sun\ F* | *Sun*Fortran*)
+	  lt_prog_compiler_pic='-KPIC'
+	  lt_prog_compiler_static='-Bstatic'
+	  lt_prog_compiler_wl='-Qoption ld '
+	  ;;
+	*Sun\ C*)
+	  # Sun C 5.9
+	  lt_prog_compiler_pic='-KPIC'
+	  lt_prog_compiler_static='-Bstatic'
+	  lt_prog_compiler_wl='-Wl,'
+	  ;;
+        *Intel*\ [CF]*Compiler*)
+	  lt_prog_compiler_wl='-Wl,'
+	  lt_prog_compiler_pic='-fPIC'
+	  lt_prog_compiler_static='-static'
+	  ;;
+	*Portland\ Group*)
+	  lt_prog_compiler_wl='-Wl,'
+	  lt_prog_compiler_pic='-fpic'
+	  lt_prog_compiler_static='-Bstatic'
+	  ;;
+	esac
+	;;
+      esac
+      ;;
+
+    newsos6)
+      lt_prog_compiler_pic='-KPIC'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    *nto* | *qnx*)
+      # QNX uses GNU C++, but need to define -shared option too, otherwise
+      # it will coredump.
+      lt_prog_compiler_pic='-fPIC -shared'
+      ;;
+
+    osf3* | osf4* | osf5*)
+      lt_prog_compiler_wl='-Wl,'
+      # All OSF/1 code is PIC.
+      lt_prog_compiler_static='-non_shared'
+      ;;
+
+    rdos*)
+      lt_prog_compiler_static='-non_shared'
+      ;;
+
+    solaris*)
+      lt_prog_compiler_pic='-KPIC'
+      lt_prog_compiler_static='-Bstatic'
+      case $cc_basename in
+      f77* | f90* | f95* | sunf77* | sunf90* | sunf95*)
+	lt_prog_compiler_wl='-Qoption ld ';;
+      *)
+	lt_prog_compiler_wl='-Wl,';;
+      esac
+      ;;
+
+    sunos4*)
+      lt_prog_compiler_wl='-Qoption ld '
+      lt_prog_compiler_pic='-PIC'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    sysv4 | sysv4.2uw2* | sysv4.3*)
+      lt_prog_compiler_wl='-Wl,'
+      lt_prog_compiler_pic='-KPIC'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	lt_prog_compiler_pic='-Kconform_pic'
+	lt_prog_compiler_static='-Bstatic'
+      fi
+      ;;
+
+    sysv5* | unixware* | sco3.2v5* | sco5v6* | OpenUNIX*)
+      lt_prog_compiler_wl='-Wl,'
+      lt_prog_compiler_pic='-KPIC'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    unicos*)
+      lt_prog_compiler_wl='-Wl,'
+      lt_prog_compiler_can_build_shared=no
+      ;;
+
+    uts4*)
+      lt_prog_compiler_pic='-pic'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    *)
+      lt_prog_compiler_can_build_shared=no
+      ;;
+    esac
+  fi
+
+case $host_os in
+  # For platforms that do not support PIC, -DPIC is meaningless:
+  *djgpp*)
+    lt_prog_compiler_pic=
+    ;;
+  *)
+    lt_prog_compiler_pic="$lt_prog_compiler_pic -DPIC"
+    ;;
+esac
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $compiler option to produce PIC" >&5
+$as_echo_n "checking for $compiler option to produce PIC... " >&6; }
+if ${lt_cv_prog_compiler_pic+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_prog_compiler_pic=$lt_prog_compiler_pic
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_pic" >&5
+$as_echo "$lt_cv_prog_compiler_pic" >&6; }
+lt_prog_compiler_pic=$lt_cv_prog_compiler_pic
+
+#
+# Check to make sure the PIC flag actually works.
+#
+if test -n "$lt_prog_compiler_pic"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if $compiler PIC flag $lt_prog_compiler_pic works" >&5
+$as_echo_n "checking if $compiler PIC flag $lt_prog_compiler_pic works... " >&6; }
+if ${lt_cv_prog_compiler_pic_works+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_prog_compiler_pic_works=no
+   ac_outfile=conftest.$ac_objext
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+   lt_compiler_flag="$lt_prog_compiler_pic -DPIC"  ## exclude from sc_useless_quotes_in_assignment
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   # The option is referenced via a variable to avoid confusing sed.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&5)
+   (eval "$lt_compile" 2>conftest.err)
+   ac_status=$?
+   cat conftest.err >&5
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   if (exit $ac_status) && test -s "$ac_outfile"; then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings other than the usual output.
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' >conftest.exp
+     $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+     if test ! -s conftest.er2 || diff conftest.exp conftest.er2 >/dev/null; then
+       lt_cv_prog_compiler_pic_works=yes
+     fi
+   fi
+   $RM conftest*
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_pic_works" >&5
+$as_echo "$lt_cv_prog_compiler_pic_works" >&6; }
+
+if test yes = "$lt_cv_prog_compiler_pic_works"; then
+    case $lt_prog_compiler_pic in
+     "" | " "*) ;;
+     *) lt_prog_compiler_pic=" $lt_prog_compiler_pic" ;;
+     esac
+else
+    lt_prog_compiler_pic=
+     lt_prog_compiler_can_build_shared=no
+fi
+
+fi
+
+
+
+
+
+
+
+
+
+
+
+#
+# Check to make sure the static flag actually works.
+#
+wl=$lt_prog_compiler_wl eval lt_tmp_static_flag=\"$lt_prog_compiler_static\"
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if $compiler static flag $lt_tmp_static_flag works" >&5
+$as_echo_n "checking if $compiler static flag $lt_tmp_static_flag works... " >&6; }
+if ${lt_cv_prog_compiler_static_works+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_prog_compiler_static_works=no
+   save_LDFLAGS=$LDFLAGS
+   LDFLAGS="$LDFLAGS $lt_tmp_static_flag"
+   echo "$lt_simple_link_test_code" > conftest.$ac_ext
+   if (eval $ac_link 2>conftest.err) && test -s conftest$ac_exeext; then
+     # The linker can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     if test -s conftest.err; then
+       # Append any errors to the config.log.
+       cat conftest.err 1>&5
+       $ECHO "$_lt_linker_boilerplate" | $SED '/^$/d' > conftest.exp
+       $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+       if diff conftest.exp conftest.er2 >/dev/null; then
+         lt_cv_prog_compiler_static_works=yes
+       fi
+     else
+       lt_cv_prog_compiler_static_works=yes
+     fi
+   fi
+   $RM -r conftest*
+   LDFLAGS=$save_LDFLAGS
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_static_works" >&5
+$as_echo "$lt_cv_prog_compiler_static_works" >&6; }
+
+if test yes = "$lt_cv_prog_compiler_static_works"; then
+    :
+else
+    lt_prog_compiler_static=
+fi
+
+
+
+
+
+
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if $compiler supports -c -o file.$ac_objext" >&5
+$as_echo_n "checking if $compiler supports -c -o file.$ac_objext... " >&6; }
+if ${lt_cv_prog_compiler_c_o+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_prog_compiler_c_o=no
+   $RM -r conftest 2>/dev/null
+   mkdir conftest
+   cd conftest
+   mkdir out
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+
+   lt_compiler_flag="-o out/conftest2.$ac_objext"
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&5)
+   (eval "$lt_compile" 2>out/conftest.err)
+   ac_status=$?
+   cat out/conftest.err >&5
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   if (exit $ac_status) && test -s out/conftest2.$ac_objext
+   then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' > out/conftest.exp
+     $SED '/^$/d; /^ *+/d' out/conftest.err >out/conftest.er2
+     if test ! -s out/conftest.er2 || diff out/conftest.exp out/conftest.er2 >/dev/null; then
+       lt_cv_prog_compiler_c_o=yes
+     fi
+   fi
+   chmod u+w . 2>&5
+   $RM conftest*
+   # SGI C++ compiler will create directory out/ii_files/ for
+   # template instantiation
+   test -d out/ii_files && $RM out/ii_files/* && rmdir out/ii_files
+   $RM out/* && rmdir out
+   cd ..
+   $RM -r conftest
+   $RM conftest*
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_c_o" >&5
+$as_echo "$lt_cv_prog_compiler_c_o" >&6; }
+
+
+
+
+
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if $compiler supports -c -o file.$ac_objext" >&5
+$as_echo_n "checking if $compiler supports -c -o file.$ac_objext... " >&6; }
+if ${lt_cv_prog_compiler_c_o+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_prog_compiler_c_o=no
+   $RM -r conftest 2>/dev/null
+   mkdir conftest
+   cd conftest
+   mkdir out
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+
+   lt_compiler_flag="-o out/conftest2.$ac_objext"
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&5)
+   (eval "$lt_compile" 2>out/conftest.err)
+   ac_status=$?
+   cat out/conftest.err >&5
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   if (exit $ac_status) && test -s out/conftest2.$ac_objext
+   then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' > out/conftest.exp
+     $SED '/^$/d; /^ *+/d' out/conftest.err >out/conftest.er2
+     if test ! -s out/conftest.er2 || diff out/conftest.exp out/conftest.er2 >/dev/null; then
+       lt_cv_prog_compiler_c_o=yes
+     fi
+   fi
+   chmod u+w . 2>&5
+   $RM conftest*
+   # SGI C++ compiler will create directory out/ii_files/ for
+   # template instantiation
+   test -d out/ii_files && $RM out/ii_files/* && rmdir out/ii_files
+   $RM out/* && rmdir out
+   cd ..
+   $RM -r conftest
+   $RM conftest*
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_c_o" >&5
+$as_echo "$lt_cv_prog_compiler_c_o" >&6; }
+
+
+
+
+hard_links=nottested
+if test no = "$lt_cv_prog_compiler_c_o" && test no != "$need_locks"; then
+  # do not overwrite the value of need_locks provided by the user
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if we can lock with hard links" >&5
+$as_echo_n "checking if we can lock with hard links... " >&6; }
+  hard_links=yes
+  $RM conftest*
+  ln conftest.a conftest.b 2>/dev/null && hard_links=no
+  touch conftest.a
+  ln conftest.a conftest.b 2>&5 || hard_links=no
+  ln conftest.a conftest.b 2>/dev/null && hard_links=no
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $hard_links" >&5
+$as_echo "$hard_links" >&6; }
+  if test no = "$hard_links"; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: '$CC' does not support '-c -o', so 'make -j' may be unsafe" >&5
+$as_echo "$as_me: WARNING: '$CC' does not support '-c -o', so 'make -j' may be unsafe" >&2;}
+    need_locks=warn
+  fi
+else
+  need_locks=no
+fi
+
+
+
+
+
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the $compiler linker ($LD) supports shared libraries" >&5
+$as_echo_n "checking whether the $compiler linker ($LD) supports shared libraries... " >&6; }
+
+  runpath_var=
+  allow_undefined_flag=
+  always_export_symbols=no
+  archive_cmds=
+  archive_expsym_cmds=
+  compiler_needs_object=no
+  enable_shared_with_static_runtimes=no
+  export_dynamic_flag_spec=
+  export_symbols_cmds='$NM $libobjs $convenience | $global_symbol_pipe | $SED '\''s/.* //'\'' | sort | uniq > $export_symbols'
+  hardcode_automatic=no
+  hardcode_direct=no
+  hardcode_direct_absolute=no
+  hardcode_libdir_flag_spec=
+  hardcode_libdir_separator=
+  hardcode_minus_L=no
+  hardcode_shlibpath_var=unsupported
+  inherit_rpath=no
+  link_all_deplibs=unknown
+  module_cmds=
+  module_expsym_cmds=
+  old_archive_from_new_cmds=
+  old_archive_from_expsyms_cmds=
+  thread_safe_flag_spec=
+  whole_archive_flag_spec=
+  # include_expsyms should be a list of space-separated symbols to be *always*
+  # included in the symbol list
+  include_expsyms=
+  # exclude_expsyms can be an extended regexp of symbols to exclude
+  # it will be wrapped by ' (' and ')$', so one must not match beginning or
+  # end of line.  Example: 'a|bc|.*d.*' will exclude the symbols 'a' and 'bc',
+  # as well as any symbol that contains 'd'.
+  exclude_expsyms='_GLOBAL_OFFSET_TABLE_|_GLOBAL__F[ID]_.*'
+  # Although _GLOBAL_OFFSET_TABLE_ is a valid symbol C name, most a.out
+  # platforms (ab)use it in PIC code, but their linkers get confused if
+  # the symbol is explicitly referenced.  Since portable code cannot
+  # rely on this symbol name, it's probably fine to never include it in
+  # preloaded symbol tables.
+  # Exclude shared library initialization/finalization symbols.
+  extract_expsyms_cmds=
+
+  case $host_os in
+  cygwin* | mingw* | pw32* | cegcc*)
+    # FIXME: the MSVC++ port hasn't been tested in a loooong time
+    # When not using gcc, we currently assume that we are using
+    # Microsoft Visual C++.
+    if test yes != "$GCC"; then
+      with_gnu_ld=no
+    fi
+    ;;
+  interix*)
+    # we just hope/assume this is gcc and not c89 (= MSVC++)
+    with_gnu_ld=yes
+    ;;
+  openbsd* | bitrig*)
+    with_gnu_ld=no
+    ;;
+  esac
+
+  ld_shlibs=yes
+
+  # On some targets, GNU ld is compatible enough with the native linker
+  # that we're better off using the native interface for both.
+  lt_use_gnu_ld_interface=no
+  if test yes = "$with_gnu_ld"; then
+    case $host_os in
+      aix*)
+	# The AIX port of GNU ld has always aspired to compatibility
+	# with the native linker.  However, as the warning in the GNU ld
+	# block says, versions before 2.19.5* couldn't really create working
+	# shared libraries, regardless of the interface used.
+	case `$LD -v 2>&1` in
+	  *\ \(GNU\ Binutils\)\ 2.19.5*) ;;
+	  *\ \(GNU\ Binutils\)\ 2.[2-9]*) ;;
+	  *\ \(GNU\ Binutils\)\ [3-9]*) ;;
+	  *)
+	    lt_use_gnu_ld_interface=yes
+	    ;;
+	esac
+	;;
+      *)
+	lt_use_gnu_ld_interface=yes
+	;;
+    esac
+  fi
+
+  if test yes = "$lt_use_gnu_ld_interface"; then
+    # If archive_cmds runs LD, not CC, wlarc should be empty
+    wlarc='$wl'
+
+    # Set some defaults for GNU ld with shared library support. These
+    # are reset later if shared libraries are not supported. Putting them
+    # here allows them to be overridden if necessary.
+    runpath_var=LD_RUN_PATH
+    hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+    export_dynamic_flag_spec='$wl--export-dynamic'
+    # ancient GNU ld didn't support --whole-archive et. al.
+    if $LD --help 2>&1 | $GREP 'no-whole-archive' > /dev/null; then
+      whole_archive_flag_spec=$wlarc'--whole-archive$convenience '$wlarc'--no-whole-archive'
+    else
+      whole_archive_flag_spec=
+    fi
+    supports_anon_versioning=no
+    case `$LD -v | $SED -e 's/(^)\+)\s\+//' 2>&1` in
+      *GNU\ gold*) supports_anon_versioning=yes ;;
+      *\ [01].* | *\ 2.[0-9].* | *\ 2.10.*) ;; # catch versions < 2.11
+      *\ 2.11.93.0.2\ *) supports_anon_versioning=yes ;; # RH7.3 ...
+      *\ 2.11.92.0.12\ *) supports_anon_versioning=yes ;; # Mandrake 8.2 ...
+      *\ 2.11.*) ;; # other 2.11 versions
+      *) supports_anon_versioning=yes ;;
+    esac
+
+    # See if GNU ld supports shared libraries.
+    case $host_os in
+    aix[3-9]*)
+      # On AIX/PPC, the GNU linker is very broken
+      if test ia64 != "$host_cpu"; then
+	ld_shlibs=no
+	cat <<_LT_EOF 1>&2
+
+*** Warning: the GNU linker, at least up to release 2.19, is reported
+*** to be unable to reliably create shared libraries on AIX.
+*** Therefore, libtool is disabling shared libraries support.  If you
+*** really care for shared libraries, you may want to install binutils
+*** 2.20 or above, or modify your PATH so that a non-GNU linker is found.
+*** You will then need to restart the configuration process.
+
+_LT_EOF
+      fi
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+            archive_expsym_cmds=''
+        ;;
+      m68k)
+            archive_cmds='$RM $output_objdir/a2ixlibrary.data~$ECHO "#define NAME $libname" > $output_objdir/a2ixlibrary.data~$ECHO "#define LIBRARY_ID 1" >> $output_objdir/a2ixlibrary.data~$ECHO "#define VERSION $major" >> $output_objdir/a2ixlibrary.data~$ECHO "#define REVISION $revision" >> $output_objdir/a2ixlibrary.data~$AR $AR_FLAGS $lib $libobjs~$RANLIB $lib~(cd $output_objdir && a2ixlibrary -32)'
+            hardcode_libdir_flag_spec='-L$libdir'
+            hardcode_minus_L=yes
+        ;;
+      esac
+      ;;
+
+    beos*)
+      if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	allow_undefined_flag=unsupported
+	# Joseph Beckenbach <jrb3@best.com> says some releases of gcc
+	# support --undefined.  This deserves some investigation.  FIXME
+	archive_cmds='$CC -nostart $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+      else
+	ld_shlibs=no
+      fi
+      ;;
+
+    cygwin* | mingw* | pw32* | cegcc*)
+      # _LT_TAGVAR(hardcode_libdir_flag_spec, ) is actually meaningless,
+      # as there is no search path for DLLs.
+      hardcode_libdir_flag_spec='-L$libdir'
+      export_dynamic_flag_spec='$wl--export-all-symbols'
+      allow_undefined_flag=unsupported
+      always_export_symbols=no
+      enable_shared_with_static_runtimes=yes
+      export_symbols_cmds='$NM $libobjs $convenience | $global_symbol_pipe | $SED -e '\''/^[BCDGRS][ ]/s/.*[ ]\([^ ]*\)/\1 DATA/;s/^.*[ ]__nm__\([^ ]*\)[ ][^ ]*/\1 DATA/;/^I[ ]/d;/^[AITW][ ]/s/.* //'\'' | sort | uniq > $export_symbols'
+      exclude_expsyms='[_]+GLOBAL_OFFSET_TABLE_|[_]+GLOBAL__[FID]_.*|[_]+head_[A-Za-z0-9_]+_dll|[A-Za-z0-9_]+_dll_iname'
+
+      if $LD --help 2>&1 | $GREP 'auto-import' > /dev/null; then
+        archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
+	# If the export-symbols file already is a .def file, use it as
+	# is; otherwise, prepend EXPORTS...
+	archive_expsym_cmds='if   test DEF = "`$SED -n     -e '\''s/^[	 ]*//'\''     -e '\''/^\(;.*\)*$/d'\''     -e '\''s/^\(EXPORTS\|LIBRARY\)\([	 ].*\)*$/DEF/p'\''     -e q     $export_symbols`" ; then
+          cp $export_symbols $output_objdir/$soname.def;
+        else
+          echo EXPORTS > $output_objdir/$soname.def;
+          cat $export_symbols >> $output_objdir/$soname.def;
+        fi~
+        $CC -shared $output_objdir/$soname.def $libobjs $deplibs $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
+      else
+	ld_shlibs=no
+      fi
+      ;;
+
+    haiku*)
+      archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+      link_all_deplibs=yes
+      ;;
+
+    os2*)
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_minus_L=yes
+      allow_undefined_flag=unsupported
+      shrext_cmds=.dll
+      archive_cmds='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	emxexp $libobjs | $SED /"_DLL_InitTerm"/d >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      archive_expsym_cmds='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	prefix_cmds="$SED"~
+	if test EXPORTS = "`$SED 1q $export_symbols`"; then
+	  prefix_cmds="$prefix_cmds -e 1d";
+	fi~
+	prefix_cmds="$prefix_cmds -e \"s/^\(.*\)$/_\1/g\""~
+	cat $export_symbols | $prefix_cmds >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      old_archive_From_new_cmds='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
+      enable_shared_with_static_runtimes=yes
+      ;;
+
+    interix[3-9]*)
+      hardcode_direct=no
+      hardcode_shlibpath_var=no
+      hardcode_libdir_flag_spec='$wl-rpath,$libdir'
+      export_dynamic_flag_spec='$wl-E'
+      # Hack: On Interix 3.x, we cannot compile PIC because of a broken gcc.
+      # Instead, shared libraries are loaded at an image base (0x10000000 by
+      # default) and relocated if they conflict, which is a slow very memory
+      # consuming and fragmenting process.  To avoid this, we pick a random,
+      # 256 KiB-aligned image base between 0x50000000 and 0x6FFC0000 at link
+      # time.  Moving up from 0x10000000 also allows more sbrk(2) space.
+      archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-h,$soname $wl--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
+      archive_expsym_cmds='sed "s|^|_|" $export_symbols >$output_objdir/$soname.expsym~$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-h,$soname $wl--retain-symbols-file,$output_objdir/$soname.expsym $wl--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
+      ;;
+
+    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu)
+      tmp_diet=no
+      if test linux-dietlibc = "$host_os"; then
+	case $cc_basename in
+	  diet\ *) tmp_diet=yes;;	# linux-dietlibc with static linking (!diet-dyn)
+	esac
+      fi
+      if $LD --help 2>&1 | $EGREP ': supported targets:.* elf' > /dev/null \
+	 && test no = "$tmp_diet"
+      then
+	tmp_addflag=' $pic_flag'
+	tmp_sharedflag='-shared'
+	case $cc_basename,$host_cpu in
+        pgcc*)				# Portland Group C compiler
+	  whole_archive_flag_spec='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  tmp_addflag=' $pic_flag'
+	  ;;
+	pgf77* | pgf90* | pgf95* | pgfortran*)
+					# Portland Group f77 and f90 compilers
+	  whole_archive_flag_spec='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  tmp_addflag=' $pic_flag -Mnomain' ;;
+	ecc*,ia64* | icc*,ia64*)	# Intel C compiler on ia64
+	  tmp_addflag=' -i_dynamic' ;;
+	efc*,ia64* | ifort*,ia64*)	# Intel Fortran compiler on ia64
+	  tmp_addflag=' -i_dynamic -nofor_main' ;;
+	ifc* | ifort*)			# Intel Fortran compiler
+	  tmp_addflag=' -nofor_main' ;;
+	lf95*)				# Lahey Fortran 8.1
+	  whole_archive_flag_spec=
+	  tmp_sharedflag='--shared' ;;
+        nagfor*)                        # NAGFOR 5.3
+          tmp_sharedflag='-Wl,-shared' ;;
+	xl[cC]* | bgxl[cC]* | mpixl[cC]*) # IBM XL C 8.0 on PPC (deal with xlf below)
+	  tmp_sharedflag='-qmkshrobj'
+	  tmp_addflag= ;;
+	nvcc*)	# Cuda Compiler Driver 2.2
+	  whole_archive_flag_spec='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  compiler_needs_object=yes
+	  ;;
+	esac
+	case `$CC -V 2>&1 | sed 5q` in
+	*Sun\ C*)			# Sun C 5.9
+	  whole_archive_flag_spec='$wl--whole-archive`new_convenience=; for conv in $convenience\"\"; do test -z \"$conv\" || new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  compiler_needs_object=yes
+	  tmp_sharedflag='-G' ;;
+	*Sun\ F*)			# Sun Fortran 8.3
+	  tmp_sharedflag='-G' ;;
+	esac
+	archive_cmds='$CC '"$tmp_sharedflag""$tmp_addflag"' $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+
+        if test yes = "$supports_anon_versioning"; then
+          archive_expsym_cmds='echo "{ global:" > $output_objdir/$libname.ver~
+            cat $export_symbols | sed -e "s/\(.*\)/\1;/" >> $output_objdir/$libname.ver~
+            echo "local: *; };" >> $output_objdir/$libname.ver~
+            $CC '"$tmp_sharedflag""$tmp_addflag"' $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-version-script $wl$output_objdir/$libname.ver -o $lib'
+        fi
+
+	case $cc_basename in
+	tcc*)
+	  export_dynamic_flag_spec='-rdynamic'
+	  ;;
+	xlf* | bgf* | bgxlf* | mpixlf*)
+	  # IBM XL Fortran 10.1 on PPC cannot create shared libs itself
+	  whole_archive_flag_spec='--whole-archive$convenience --no-whole-archive'
+	  hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+	  archive_cmds='$LD -shared $libobjs $deplibs $linker_flags -soname $soname -o $lib'
+	  if test yes = "$supports_anon_versioning"; then
+	    archive_expsym_cmds='echo "{ global:" > $output_objdir/$libname.ver~
+              cat $export_symbols | sed -e "s/\(.*\)/\1;/" >> $output_objdir/$libname.ver~
+              echo "local: *; };" >> $output_objdir/$libname.ver~
+              $LD -shared $libobjs $deplibs $linker_flags -soname $soname -version-script $output_objdir/$libname.ver -o $lib'
+	  fi
+	  ;;
+	esac
+      else
+        ld_shlibs=no
+      fi
+      ;;
+
+    netbsd*)
+      if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+	archive_cmds='$LD -Bshareable $libobjs $deplibs $linker_flags -o $lib'
+	wlarc=
+      else
+	archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	archive_expsym_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+      fi
+      ;;
+
+    solaris*)
+      if $LD -v 2>&1 | $GREP 'BFD 2\.8' > /dev/null; then
+	ld_shlibs=no
+	cat <<_LT_EOF 1>&2
+
+*** Warning: The releases 2.8.* of the GNU linker cannot reliably
+*** create shared libraries on Solaris systems.  Therefore, libtool
+*** is disabling shared libraries support.  We urge you to upgrade GNU
+*** binutils to release 2.9.1 or newer.  Another option is to modify
+*** your PATH or compiler configuration so that the native linker is
+*** used, and then restart.
+
+_LT_EOF
+      elif $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	archive_expsym_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+      else
+	ld_shlibs=no
+      fi
+      ;;
+
+    sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX*)
+      case `$LD -v 2>&1` in
+        *\ [01].* | *\ 2.[0-9].* | *\ 2.1[0-5].*)
+	ld_shlibs=no
+	cat <<_LT_EOF 1>&2
+
+*** Warning: Releases of the GNU linker prior to 2.16.91.0.3 cannot
+*** reliably create shared libraries on SCO systems.  Therefore, libtool
+*** is disabling shared libraries support.  We urge you to upgrade GNU
+*** binutils to release 2.16.91.0.3 or newer.  Another option is to modify
+*** your PATH or compiler configuration so that the native linker is
+*** used, and then restart.
+
+_LT_EOF
+	;;
+	*)
+	  # For security reasons, it is highly recommended that you always
+	  # use absolute paths for naming shared libraries, and exclude the
+	  # DT_RUNPATH tag from executables and libraries.  But doing so
+	  # requires that you compile everything twice, which is a pain.
+	  if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	    hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+	    archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	    archive_expsym_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+	  else
+	    ld_shlibs=no
+	  fi
+	;;
+      esac
+      ;;
+
+    sunos4*)
+      archive_cmds='$LD -assert pure-text -Bshareable -o $lib $libobjs $deplibs $linker_flags'
+      wlarc=
+      hardcode_direct=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    *)
+      if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	archive_expsym_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+      else
+	ld_shlibs=no
+      fi
+      ;;
+    esac
+
+    if test no = "$ld_shlibs"; then
+      runpath_var=
+      hardcode_libdir_flag_spec=
+      export_dynamic_flag_spec=
+      whole_archive_flag_spec=
+    fi
+  else
+    # PORTME fill in a description of your system's linker (not GNU ld)
+    case $host_os in
+    aix3*)
+      allow_undefined_flag=unsupported
+      always_export_symbols=yes
+      archive_expsym_cmds='$LD -o $output_objdir/$soname $libobjs $deplibs $linker_flags -bE:$export_symbols -T512 -H512 -bM:SRE~$AR $AR_FLAGS $lib $output_objdir/$soname'
+      # Note: this linker hardcodes the directories in LIBPATH if there
+      # are no directories specified by -L.
+      hardcode_minus_L=yes
+      if test yes = "$GCC" && test -z "$lt_prog_compiler_static"; then
+	# Neither direct hardcoding nor static linking is supported with a
+	# broken collect2.
+	hardcode_direct=unsupported
+      fi
+      ;;
+
+    aix[4-9]*)
+      if test ia64 = "$host_cpu"; then
+	# On IA64, the linker does run time linking by default, so we don't
+	# have to do anything special.
+	aix_use_runtimelinking=no
+	exp_sym_flag='-Bexport'
+	no_entry_flag=
+      else
+	# If we're using GNU nm, then we don't want the "-C" option.
+	# -C means demangle to GNU nm, but means don't demangle to AIX nm.
+	# Without the "-l" option, or with the "-B" option, AIX nm treats
+	# weak defined symbols like other global defined symbols, whereas
+	# GNU nm marks them as "W".
+	# While the 'weak' keyword is ignored in the Export File, we need
+	# it in the Import File for the 'aix-soname' feature, so we have
+	# to replace the "-B" option with "-P" for AIX nm.
+	if $NM -V 2>&1 | $GREP 'GNU' > /dev/null; then
+	  export_symbols_cmds='$NM -Bpg $libobjs $convenience | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "W")) && (substr(\$ 3,1,1) != ".")) { if (\$ 2 == "W") { print \$ 3 " weak" } else { print \$ 3 } } }'\'' | sort -u > $export_symbols'
+	else
+	  export_symbols_cmds='`func_echo_all $NM | $SED -e '\''s/B\([^B]*\)$/P\1/'\''` -PCpgl $libobjs $convenience | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) && (substr(\$ 1,1,1) != ".")) { if ((\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) { print \$ 1 " weak" } else { print \$ 1 } } }'\'' | sort -u > $export_symbols'
+	fi
+	aix_use_runtimelinking=no
+
+	# Test if we are trying to use run time linking or normal
+	# AIX style linking. If -brtl is somewhere in LDFLAGS, we
+	# have runtime linking enabled, and use it for executables.
+	# For shared libraries, we enable/disable runtime linking
+	# depending on the kind of the shared library created -
+	# when "with_aix_soname,aix_use_runtimelinking" is:
+	# "aix,no"   lib.a(lib.so.V) shared, rtl:no,  for executables
+	# "aix,yes"  lib.so          shared, rtl:yes, for executables
+	#            lib.a           static archive
+	# "both,no"  lib.so.V(shr.o) shared, rtl:yes
+	#            lib.a(lib.so.V) shared, rtl:no,  for executables
+	# "both,yes" lib.so.V(shr.o) shared, rtl:yes, for executables
+	#            lib.a(lib.so.V) shared, rtl:no
+	# "svr4,*"   lib.so.V(shr.o) shared, rtl:yes, for executables
+	#            lib.a           static archive
+	case $host_os in aix4.[23]|aix4.[23].*|aix[5-9]*)
+	  for ld_flag in $LDFLAGS; do
+	  if (test x-brtl = "x$ld_flag" || test x-Wl,-brtl = "x$ld_flag"); then
+	    aix_use_runtimelinking=yes
+	    break
+	  fi
+	  done
+	  if test svr4,no = "$with_aix_soname,$aix_use_runtimelinking"; then
+	    # With aix-soname=svr4, we create the lib.so.V shared archives only,
+	    # so we don't have lib.a shared libs to link our executables.
+	    # We have to force runtime linking in this case.
+	    aix_use_runtimelinking=yes
+	    LDFLAGS="$LDFLAGS -Wl,-brtl"
+	  fi
+	  ;;
+	esac
+
+	exp_sym_flag='-bexport'
+	no_entry_flag='-bnoentry'
+      fi
+
+      # When large executables or shared objects are built, AIX ld can
+      # have problems creating the table of contents.  If linking a library
+      # or program results in "error TOC overflow" add -mminimal-toc to
+      # CXXFLAGS/CFLAGS for g++/gcc.  In the cases where that is not
+      # enough to fix the problem, add -Wl,-bbigtoc to LDFLAGS.
+
+      archive_cmds=''
+      hardcode_direct=yes
+      hardcode_direct_absolute=yes
+      hardcode_libdir_separator=':'
+      link_all_deplibs=yes
+      file_list_spec='$wl-f,'
+      case $with_aix_soname,$aix_use_runtimelinking in
+      aix,*) ;; # traditional, no import file
+      svr4,* | *,yes) # use import file
+	# The Import File defines what to hardcode.
+	hardcode_direct=no
+	hardcode_direct_absolute=no
+	;;
+      esac
+
+      if test yes = "$GCC"; then
+	case $host_os in aix4.[012]|aix4.[012].*)
+	# We only want to do this on AIX 4.2 and lower, the check
+	# below for broken collect2 doesn't work under 4.3+
+	  collect2name=`$CC -print-prog-name=collect2`
+	  if test -f "$collect2name" &&
+	   strings "$collect2name" | $GREP resolve_lib_name >/dev/null
+	  then
+	  # We have reworked collect2
+	  :
+	  else
+	  # We have old collect2
+	  hardcode_direct=unsupported
+	  # It fails to find uninstalled libraries when the uninstalled
+	  # path is not listed in the libpath.  Setting hardcode_minus_L
+	  # to unsupported forces relinking
+	  hardcode_minus_L=yes
+	  hardcode_libdir_flag_spec='-L$libdir'
+	  hardcode_libdir_separator=
+	  fi
+	  ;;
+	esac
+	shared_flag='-shared'
+	if test yes = "$aix_use_runtimelinking"; then
+	  shared_flag="$shared_flag "'$wl-G'
+	fi
+	# Need to ensure runtime linking is disabled for the traditional
+	# shared library, or the linker may eventually find shared libraries
+	# /with/ Import File - we do not want to mix them.
+	shared_flag_aix='-shared'
+	shared_flag_svr4='-shared $wl-G'
+      else
+	# not using gcc
+	if test ia64 = "$host_cpu"; then
+	# VisualAge C++, Version 5.5 for AIX 5L for IA-64, Beta 3 Release
+	# chokes on -Wl,-G. The following line is correct:
+	  shared_flag='-G'
+	else
+	  if test yes = "$aix_use_runtimelinking"; then
+	    shared_flag='$wl-G'
+	  else
+	    shared_flag='$wl-bM:SRE'
+	  fi
+	  shared_flag_aix='$wl-bM:SRE'
+	  shared_flag_svr4='$wl-G'
+	fi
+      fi
+
+      export_dynamic_flag_spec='$wl-bexpall'
+      # It seems that -bexpall does not export symbols beginning with
+      # underscore (_), so it is better to generate a list of symbols to export.
+      always_export_symbols=yes
+      if test aix,yes = "$with_aix_soname,$aix_use_runtimelinking"; then
+	# Warning - without using the other runtime loading flags (-brtl),
+	# -berok will link without error, but may produce a broken library.
+	allow_undefined_flag='-berok'
+        # Determine the default libpath from the value encoded in an
+        # empty executable.
+        if test set = "${lt_cv_aix_libpath+set}"; then
+  aix_libpath=$lt_cv_aix_libpath
+else
+  if ${lt_cv_aix_libpath_+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+
+  lt_aix_libpath_sed='
+      /Import File Strings/,/^$/ {
+	  /^0/ {
+	      s/^0  *\([^ ]*\) *$/\1/
+	      p
+	  }
+      }'
+  lt_cv_aix_libpath_=`dump -H conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  # Check for a 64-bit object if we didn't find anything.
+  if test -z "$lt_cv_aix_libpath_"; then
+    lt_cv_aix_libpath_=`dump -HX64 conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  fi
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+  if test -z "$lt_cv_aix_libpath_"; then
+    lt_cv_aix_libpath_=/usr/lib:/lib
+  fi
+
+fi
+
+  aix_libpath=$lt_cv_aix_libpath_
+fi
+
+        hardcode_libdir_flag_spec='$wl-blibpath:$libdir:'"$aix_libpath"
+        archive_expsym_cmds='$CC -o $output_objdir/$soname $libobjs $deplibs $wl'$no_entry_flag' $compiler_flags `if test -n "$allow_undefined_flag"; then func_echo_all "$wl$allow_undefined_flag"; else :; fi` $wl'$exp_sym_flag:\$export_symbols' '$shared_flag
+      else
+	if test ia64 = "$host_cpu"; then
+	  hardcode_libdir_flag_spec='$wl-R $libdir:/usr/lib:/lib'
+	  allow_undefined_flag="-z nodefs"
+	  archive_expsym_cmds="\$CC $shared_flag"' -o $output_objdir/$soname $libobjs $deplibs '"\$wl$no_entry_flag"' $compiler_flags $wl$allow_undefined_flag '"\$wl$exp_sym_flag:\$export_symbols"
+	else
+	 # Determine the default libpath from the value encoded in an
+	 # empty executable.
+	 if test set = "${lt_cv_aix_libpath+set}"; then
+  aix_libpath=$lt_cv_aix_libpath
+else
+  if ${lt_cv_aix_libpath_+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+
+  lt_aix_libpath_sed='
+      /Import File Strings/,/^$/ {
+	  /^0/ {
+	      s/^0  *\([^ ]*\) *$/\1/
+	      p
+	  }
+      }'
+  lt_cv_aix_libpath_=`dump -H conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  # Check for a 64-bit object if we didn't find anything.
+  if test -z "$lt_cv_aix_libpath_"; then
+    lt_cv_aix_libpath_=`dump -HX64 conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  fi
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+  if test -z "$lt_cv_aix_libpath_"; then
+    lt_cv_aix_libpath_=/usr/lib:/lib
+  fi
+
+fi
+
+  aix_libpath=$lt_cv_aix_libpath_
+fi
+
+	 hardcode_libdir_flag_spec='$wl-blibpath:$libdir:'"$aix_libpath"
+	  # Warning - without using the other run time loading flags,
+	  # -berok will link without error, but may produce a broken library.
+	  no_undefined_flag=' $wl-bernotok'
+	  allow_undefined_flag=' $wl-berok'
+	  if test yes = "$with_gnu_ld"; then
+	    # We only use this code for GNU lds that support --whole-archive.
+	    whole_archive_flag_spec='$wl--whole-archive$convenience $wl--no-whole-archive'
+	  else
+	    # Exported symbols can be pulled into shared objects from archives
+	    whole_archive_flag_spec='$convenience'
+	  fi
+	  archive_cmds_need_lc=yes
+	  archive_expsym_cmds='$RM -r $output_objdir/$realname.d~$MKDIR $output_objdir/$realname.d'
+	  # -brtl affects multiple linker settings, -berok does not and is overridden later
+	  compiler_flags_filtered='`func_echo_all "$compiler_flags " | $SED -e "s%-brtl\\([, ]\\)%-berok\\1%g"`'
+	  if test svr4 != "$with_aix_soname"; then
+	    # This is similar to how AIX traditionally builds its shared libraries.
+	    archive_expsym_cmds="$archive_expsym_cmds"'~$CC '$shared_flag_aix' -o $output_objdir/$realname.d/$soname $libobjs $deplibs $wl-bnoentry '$compiler_flags_filtered'$wl-bE:$export_symbols$allow_undefined_flag~$AR $AR_FLAGS $output_objdir/$libname$release.a $output_objdir/$realname.d/$soname'
+	  fi
+	  if test aix != "$with_aix_soname"; then
+	    archive_expsym_cmds="$archive_expsym_cmds"'~$CC '$shared_flag_svr4' -o $output_objdir/$realname.d/$shared_archive_member_spec.o $libobjs $deplibs $wl-bnoentry '$compiler_flags_filtered'$wl-bE:$export_symbols$allow_undefined_flag~$STRIP -e $output_objdir/$realname.d/$shared_archive_member_spec.o~( func_echo_all "#! $soname($shared_archive_member_spec.o)"; if test shr_64 = "$shared_archive_member_spec"; then func_echo_all "# 64"; else func_echo_all "# 32"; fi; cat $export_symbols ) > $output_objdir/$realname.d/$shared_archive_member_spec.imp~$AR $AR_FLAGS $output_objdir/$soname $output_objdir/$realname.d/$shared_archive_member_spec.o $output_objdir/$realname.d/$shared_archive_member_spec.imp'
+	  else
+	    # used by -dlpreopen to get the symbols
+	    archive_expsym_cmds="$archive_expsym_cmds"'~$MV  $output_objdir/$realname.d/$soname $output_objdir'
+	  fi
+	  archive_expsym_cmds="$archive_expsym_cmds"'~$RM -r $output_objdir/$realname.d'
+	fi
+      fi
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+            archive_expsym_cmds=''
+        ;;
+      m68k)
+            archive_cmds='$RM $output_objdir/a2ixlibrary.data~$ECHO "#define NAME $libname" > $output_objdir/a2ixlibrary.data~$ECHO "#define LIBRARY_ID 1" >> $output_objdir/a2ixlibrary.data~$ECHO "#define VERSION $major" >> $output_objdir/a2ixlibrary.data~$ECHO "#define REVISION $revision" >> $output_objdir/a2ixlibrary.data~$AR $AR_FLAGS $lib $libobjs~$RANLIB $lib~(cd $output_objdir && a2ixlibrary -32)'
+            hardcode_libdir_flag_spec='-L$libdir'
+            hardcode_minus_L=yes
+        ;;
+      esac
+      ;;
+
+    bsdi[45]*)
+      export_dynamic_flag_spec=-rdynamic
+      ;;
+
+    cygwin* | mingw* | pw32* | cegcc*)
+      # When not using gcc, we currently assume that we are using
+      # Microsoft Visual C++.
+      # hardcode_libdir_flag_spec is actually meaningless, as there is
+      # no search path for DLLs.
+      case $cc_basename in
+      cl*)
+	# Native MSVC
+	hardcode_libdir_flag_spec=' '
+	allow_undefined_flag=unsupported
+	always_export_symbols=yes
+	file_list_spec='@'
+	# Tell ltmain to make .lib files, not .a files.
+	libext=lib
+	# Tell ltmain to make .dll files, not .so files.
+	shrext_cmds=.dll
+	# FIXME: Setting linknames here is a bad hack.
+	archive_cmds='$CC -o $output_objdir/$soname $libobjs $compiler_flags $deplibs -Wl,-DLL,-IMPLIB:"$tool_output_objdir$libname.dll.lib"~linknames='
+	archive_expsym_cmds='if   test DEF = "`$SED -n     -e '\''s/^[	 ]*//'\''     -e '\''/^\(;.*\)*$/d'\''     -e '\''s/^\(EXPORTS\|LIBRARY\)\([	 ].*\)*$/DEF/p'\''     -e q     $export_symbols`" ; then
+            cp "$export_symbols" "$output_objdir/$soname.def";
+            echo "$tool_output_objdir$soname.def" > "$output_objdir/$soname.exp";
+          else
+            $SED -e '\''s/^/-link -EXPORT:/'\'' < $export_symbols > $output_objdir/$soname.exp;
+          fi~
+          $CC -o $tool_output_objdir$soname $libobjs $compiler_flags $deplibs "@$tool_output_objdir$soname.exp" -Wl,-DLL,-IMPLIB:"$tool_output_objdir$libname.dll.lib"~
+          linknames='
+	# The linker will not automatically build a static lib if we build a DLL.
+	# _LT_TAGVAR(old_archive_from_new_cmds, )='true'
+	enable_shared_with_static_runtimes=yes
+	exclude_expsyms='_NULL_IMPORT_DESCRIPTOR|_IMPORT_DESCRIPTOR_.*'
+	export_symbols_cmds='$NM $libobjs $convenience | $global_symbol_pipe | $SED -e '\''/^[BCDGRS][ ]/s/.*[ ]\([^ ]*\)/\1,DATA/'\'' | $SED -e '\''/^[AITW][ ]/s/.*[ ]//'\'' | sort | uniq > $export_symbols'
+	# Don't use ranlib
+	old_postinstall_cmds='chmod 644 $oldlib'
+	postlink_cmds='lt_outputfile="@OUTPUT@"~
+          lt_tool_outputfile="@TOOL_OUTPUT@"~
+          case $lt_outputfile in
+            *.exe|*.EXE) ;;
+            *)
+              lt_outputfile=$lt_outputfile.exe
+              lt_tool_outputfile=$lt_tool_outputfile.exe
+              ;;
+          esac~
+          if test : != "$MANIFEST_TOOL" && test -f "$lt_outputfile.manifest"; then
+            $MANIFEST_TOOL -manifest "$lt_tool_outputfile.manifest" -outputresource:"$lt_tool_outputfile" || exit 1;
+            $RM "$lt_outputfile.manifest";
+          fi'
+	;;
+      *)
+	# Assume MSVC wrapper
+	hardcode_libdir_flag_spec=' '
+	allow_undefined_flag=unsupported
+	# Tell ltmain to make .lib files, not .a files.
+	libext=lib
+	# Tell ltmain to make .dll files, not .so files.
+	shrext_cmds=.dll
+	# FIXME: Setting linknames here is a bad hack.
+	archive_cmds='$CC -o $lib $libobjs $compiler_flags `func_echo_all "$deplibs" | $SED '\''s/ -lc$//'\''` -link -dll~linknames='
+	# The linker will automatically build a .lib file if we build a DLL.
+	old_archive_from_new_cmds='true'
+	# FIXME: Should let the user specify the lib program.
+	old_archive_cmds='lib -OUT:$oldlib$oldobjs$old_deplibs'
+	enable_shared_with_static_runtimes=yes
+	;;
+      esac
+      ;;
+
+    darwin* | rhapsody*)
+
+
+  archive_cmds_need_lc=no
+  hardcode_direct=no
+  hardcode_automatic=yes
+  hardcode_shlibpath_var=unsupported
+  if test yes = "$lt_cv_ld_force_load"; then
+    whole_archive_flag_spec='`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience $wl-force_load,$conv\"; done; func_echo_all \"$new_convenience\"`'
+
+  else
+    whole_archive_flag_spec=''
+  fi
+  link_all_deplibs=yes
+  allow_undefined_flag=$_lt_dar_allow_undefined
+  case $cc_basename in
+     ifort*|nagfor*) _lt_dar_can_shared=yes ;;
+     *) _lt_dar_can_shared=$GCC ;;
+  esac
+  if test yes = "$_lt_dar_can_shared"; then
+    output_verbose_link_cmd=func_echo_all
+    archive_cmds="\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring $_lt_dar_single_mod$_lt_dsymutil"
+    module_cmds="\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags$_lt_dsymutil"
+    archive_expsym_cmds="sed 's|^|_|' < \$export_symbols > \$output_objdir/\$libname-symbols.expsym~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring $_lt_dar_single_mod$_lt_dar_export_syms$_lt_dsymutil"
+    module_expsym_cmds="sed -e 's|^|_|' < \$export_symbols > \$output_objdir/\$libname-symbols.expsym~\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags$_lt_dar_export_syms$_lt_dsymutil"
+
+  else
+  ld_shlibs=no
+  fi
+
+      ;;
+
+    dgux*)
+      archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_shlibpath_var=no
+      ;;
+
+    # FreeBSD 2.2.[012] allows us to include c++rt0.o to get C++ constructor
+    # support.  Future versions do this automatically, but an explicit c++rt0.o
+    # does not break anything, and helps significantly (at the cost of a little
+    # extra space).
+    freebsd2.2*)
+      archive_cmds='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags /usr/lib/c++rt0.o'
+      hardcode_libdir_flag_spec='-R$libdir'
+      hardcode_direct=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    # Unfortunately, older versions of FreeBSD 2 do not have this feature.
+    freebsd2.*)
+      archive_cmds='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_direct=yes
+      hardcode_minus_L=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    # FreeBSD 3 and greater uses gcc -shared to do shared libraries.
+    freebsd* | dragonfly*)
+      archive_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+      hardcode_libdir_flag_spec='-R$libdir'
+      hardcode_direct=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    hpux9*)
+      if test yes = "$GCC"; then
+	archive_cmds='$RM $output_objdir/$soname~$CC -shared $pic_flag $wl+b $wl$install_libdir -o $output_objdir/$soname $libobjs $deplibs $compiler_flags~test "x$output_objdir/$soname" = "x$lib" || mv $output_objdir/$soname $lib'
+      else
+	archive_cmds='$RM $output_objdir/$soname~$LD -b +b $install_libdir -o $output_objdir/$soname $libobjs $deplibs $linker_flags~test "x$output_objdir/$soname" = "x$lib" || mv $output_objdir/$soname $lib'
+      fi
+      hardcode_libdir_flag_spec='$wl+b $wl$libdir'
+      hardcode_libdir_separator=:
+      hardcode_direct=yes
+
+      # hardcode_minus_L: Not really in the search PATH,
+      # but as the default location of the library.
+      hardcode_minus_L=yes
+      export_dynamic_flag_spec='$wl-E'
+      ;;
+
+    hpux10*)
+      if test yes,no = "$GCC,$with_gnu_ld"; then
+	archive_cmds='$CC -shared $pic_flag $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	archive_cmds='$LD -b +h $soname +b $install_libdir -o $lib $libobjs $deplibs $linker_flags'
+      fi
+      if test no = "$with_gnu_ld"; then
+	hardcode_libdir_flag_spec='$wl+b $wl$libdir'
+	hardcode_libdir_separator=:
+	hardcode_direct=yes
+	hardcode_direct_absolute=yes
+	export_dynamic_flag_spec='$wl-E'
+	# hardcode_minus_L: Not really in the search PATH,
+	# but as the default location of the library.
+	hardcode_minus_L=yes
+      fi
+      ;;
+
+    hpux11*)
+      if test yes,no = "$GCC,$with_gnu_ld"; then
+	case $host_cpu in
+	hppa*64*)
+	  archive_cmds='$CC -shared $wl+h $wl$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	ia64*)
+	  archive_cmds='$CC -shared $pic_flag $wl+h $wl$soname $wl+nodefaultrpath -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	*)
+	  archive_cmds='$CC -shared $pic_flag $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	esac
+      else
+	case $host_cpu in
+	hppa*64*)
+	  archive_cmds='$CC -b $wl+h $wl$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	ia64*)
+	  archive_cmds='$CC -b $wl+h $wl$soname $wl+nodefaultrpath -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	*)
+
+	  # Older versions of the 11.00 compiler do not understand -b yet
+	  # (HP92453-01 A.11.01.20 doesn't, HP92453-01 B.11.X.35175-35176.GP does)
+	  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if $CC understands -b" >&5
+$as_echo_n "checking if $CC understands -b... " >&6; }
+if ${lt_cv_prog_compiler__b+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_prog_compiler__b=no
+   save_LDFLAGS=$LDFLAGS
+   LDFLAGS="$LDFLAGS -b"
+   echo "$lt_simple_link_test_code" > conftest.$ac_ext
+   if (eval $ac_link 2>conftest.err) && test -s conftest$ac_exeext; then
+     # The linker can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     if test -s conftest.err; then
+       # Append any errors to the config.log.
+       cat conftest.err 1>&5
+       $ECHO "$_lt_linker_boilerplate" | $SED '/^$/d' > conftest.exp
+       $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+       if diff conftest.exp conftest.er2 >/dev/null; then
+         lt_cv_prog_compiler__b=yes
+       fi
+     else
+       lt_cv_prog_compiler__b=yes
+     fi
+   fi
+   $RM -r conftest*
+   LDFLAGS=$save_LDFLAGS
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler__b" >&5
+$as_echo "$lt_cv_prog_compiler__b" >&6; }
+
+if test yes = "$lt_cv_prog_compiler__b"; then
+    archive_cmds='$CC -b $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'
+else
+    archive_cmds='$LD -b +h $soname +b $install_libdir -o $lib $libobjs $deplibs $linker_flags'
+fi
+
+	  ;;
+	esac
+      fi
+      if test no = "$with_gnu_ld"; then
+	hardcode_libdir_flag_spec='$wl+b $wl$libdir'
+	hardcode_libdir_separator=:
+
+	case $host_cpu in
+	hppa*64*|ia64*)
+	  hardcode_direct=no
+	  hardcode_shlibpath_var=no
+	  ;;
+	*)
+	  hardcode_direct=yes
+	  hardcode_direct_absolute=yes
+	  export_dynamic_flag_spec='$wl-E'
+
+	  # hardcode_minus_L: Not really in the search PATH,
+	  # but as the default location of the library.
+	  hardcode_minus_L=yes
+	  ;;
+	esac
+      fi
+      ;;
+
+    irix5* | irix6* | nonstopux*)
+      if test yes = "$GCC"; then
+	archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+	# Try to use the -exported_symbol ld option, if it does not
+	# work, assume that -exports_file does not work either and
+	# implicitly export all symbols.
+	# This should be the same for all languages, so no per-tag cache variable.
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the $host_os linker accepts -exported_symbol" >&5
+$as_echo_n "checking whether the $host_os linker accepts -exported_symbol... " >&6; }
+if ${lt_cv_irix_exported_symbol+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  save_LDFLAGS=$LDFLAGS
+	   LDFLAGS="$LDFLAGS -shared $wl-exported_symbol ${wl}foo $wl-update_registry $wl/dev/null"
+	   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+int foo (void) { return 0; }
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  lt_cv_irix_exported_symbol=yes
+else
+  lt_cv_irix_exported_symbol=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+           LDFLAGS=$save_LDFLAGS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_irix_exported_symbol" >&5
+$as_echo "$lt_cv_irix_exported_symbol" >&6; }
+	if test yes = "$lt_cv_irix_exported_symbol"; then
+          archive_expsym_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations $wl-exports_file $wl$export_symbols -o $lib'
+	fi
+      else
+	archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+	archive_expsym_cmds='$CC -shared $libobjs $deplibs $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -exports_file $export_symbols -o $lib'
+      fi
+      archive_cmds_need_lc='no'
+      hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+      hardcode_libdir_separator=:
+      inherit_rpath=yes
+      link_all_deplibs=yes
+      ;;
+
+    linux*)
+      case $cc_basename in
+      tcc*)
+	# Fabrice Bellard et al's Tiny C Compiler
+	ld_shlibs=yes
+	archive_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+	;;
+      esac
+      ;;
+
+    netbsd*)
+      if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+	archive_cmds='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags'  # a.out
+      else
+	archive_cmds='$LD -shared -o $lib $libobjs $deplibs $linker_flags'      # ELF
+      fi
+      hardcode_libdir_flag_spec='-R$libdir'
+      hardcode_direct=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    newsos6)
+      archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_direct=yes
+      hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+      hardcode_libdir_separator=:
+      hardcode_shlibpath_var=no
+      ;;
+
+    *nto* | *qnx*)
+      ;;
+
+    openbsd* | bitrig*)
+      if test -f /usr/libexec/ld.so; then
+	hardcode_direct=yes
+	hardcode_shlibpath_var=no
+	hardcode_direct_absolute=yes
+	if test -z "`echo __ELF__ | $CC -E - | $GREP __ELF__`"; then
+	  archive_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+	  archive_expsym_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags $wl-retain-symbols-file,$export_symbols'
+	  hardcode_libdir_flag_spec='$wl-rpath,$libdir'
+	  export_dynamic_flag_spec='$wl-E'
+	else
+	  archive_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+	  hardcode_libdir_flag_spec='$wl-rpath,$libdir'
+	fi
+      else
+	ld_shlibs=no
+      fi
+      ;;
+
+    os2*)
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_minus_L=yes
+      allow_undefined_flag=unsupported
+      shrext_cmds=.dll
+      archive_cmds='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	emxexp $libobjs | $SED /"_DLL_InitTerm"/d >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      archive_expsym_cmds='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	prefix_cmds="$SED"~
+	if test EXPORTS = "`$SED 1q $export_symbols`"; then
+	  prefix_cmds="$prefix_cmds -e 1d";
+	fi~
+	prefix_cmds="$prefix_cmds -e \"s/^\(.*\)$/_\1/g\""~
+	cat $export_symbols | $prefix_cmds >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      old_archive_From_new_cmds='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
+      enable_shared_with_static_runtimes=yes
+      ;;
+
+    osf3*)
+      if test yes = "$GCC"; then
+	allow_undefined_flag=' $wl-expect_unresolved $wl\*'
+	archive_cmds='$CC -shared$allow_undefined_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+      else
+	allow_undefined_flag=' -expect_unresolved \*'
+	archive_cmds='$CC -shared$allow_undefined_flag $libobjs $deplibs $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+      fi
+      archive_cmds_need_lc='no'
+      hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+      hardcode_libdir_separator=:
+      ;;
+
+    osf4* | osf5*)	# as osf3* with the addition of -msym flag
+      if test yes = "$GCC"; then
+	allow_undefined_flag=' $wl-expect_unresolved $wl\*'
+	archive_cmds='$CC -shared$allow_undefined_flag $pic_flag $libobjs $deplibs $compiler_flags $wl-msym $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+	hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+      else
+	allow_undefined_flag=' -expect_unresolved \*'
+	archive_cmds='$CC -shared$allow_undefined_flag $libobjs $deplibs $compiler_flags -msym -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+	archive_expsym_cmds='for i in `cat $export_symbols`; do printf "%s %s\\n" -exported_symbol "\$i" >> $lib.exp; done; printf "%s\\n" "-hidden">> $lib.exp~
+          $CC -shared$allow_undefined_flag $wl-input $wl$lib.exp $compiler_flags $libobjs $deplibs -soname $soname `test -n "$verstring" && $ECHO "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib~$RM $lib.exp'
+
+	# Both c and cxx compiler support -rpath directly
+	hardcode_libdir_flag_spec='-rpath $libdir'
+      fi
+      archive_cmds_need_lc='no'
+      hardcode_libdir_separator=:
+      ;;
+
+    solaris*)
+      no_undefined_flag=' -z defs'
+      if test yes = "$GCC"; then
+	wlarc='$wl'
+	archive_cmds='$CC -shared $pic_flag $wl-z ${wl}text $wl-h $wl$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+          $CC -shared $pic_flag $wl-z ${wl}text $wl-M $wl$lib.exp $wl-h $wl$soname -o $lib $libobjs $deplibs $compiler_flags~$RM $lib.exp'
+      else
+	case `$CC -V 2>&1` in
+	*"Compilers 5.0"*)
+	  wlarc=''
+	  archive_cmds='$LD -G$allow_undefined_flag -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	  archive_expsym_cmds='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+            $LD -G$allow_undefined_flag -M $lib.exp -h $soname -o $lib $libobjs $deplibs $linker_flags~$RM $lib.exp'
+	  ;;
+	*)
+	  wlarc='$wl'
+	  archive_cmds='$CC -G$allow_undefined_flag -h $soname -o $lib $libobjs $deplibs $compiler_flags'
+	  archive_expsym_cmds='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+            $CC -G$allow_undefined_flag -M $lib.exp -h $soname -o $lib $libobjs $deplibs $compiler_flags~$RM $lib.exp'
+	  ;;
+	esac
+      fi
+      hardcode_libdir_flag_spec='-R$libdir'
+      hardcode_shlibpath_var=no
+      case $host_os in
+      solaris2.[0-5] | solaris2.[0-5].*) ;;
+      *)
+	# The compiler driver will combine and reorder linker options,
+	# but understands '-z linker_flag'.  GCC discards it without '$wl',
+	# but is careful enough not to reorder.
+	# Supported since Solaris 2.6 (maybe 2.5.1?)
+	if test yes = "$GCC"; then
+	  whole_archive_flag_spec='$wl-z ${wl}allextract$convenience $wl-z ${wl}defaultextract'
+	else
+	  whole_archive_flag_spec='-z allextract$convenience -z defaultextract'
+	fi
+	;;
+      esac
+      link_all_deplibs=yes
+      ;;
+
+    sunos4*)
+      if test sequent = "$host_vendor"; then
+	# Use $CC to link under sequent, because it throws in some extra .o
+	# files that make .init and .fini sections work.
+	archive_cmds='$CC -G $wl-h $soname -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	archive_cmds='$LD -assert pure-text -Bstatic -o $lib $libobjs $deplibs $linker_flags'
+      fi
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_direct=yes
+      hardcode_minus_L=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    sysv4)
+      case $host_vendor in
+	sni)
+	  archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	  hardcode_direct=yes # is this really true???
+	;;
+	siemens)
+	  ## LD is ld it makes a PLAMLIB
+	  ## CC just makes a GrossModule.
+	  archive_cmds='$LD -G -o $lib $libobjs $deplibs $linker_flags'
+	  reload_cmds='$CC -r -o $output$reload_objs'
+	  hardcode_direct=no
+        ;;
+	motorola)
+	  archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	  hardcode_direct=no #Motorola manual says yes, but my tests say they lie
+	;;
+      esac
+      runpath_var='LD_RUN_PATH'
+      hardcode_shlibpath_var=no
+      ;;
+
+    sysv4.3*)
+      archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_shlibpath_var=no
+      export_dynamic_flag_spec='-Bexport'
+      ;;
+
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	hardcode_shlibpath_var=no
+	runpath_var=LD_RUN_PATH
+	hardcode_runpath_var=yes
+	ld_shlibs=yes
+      fi
+      ;;
+
+    sysv4*uw2* | sysv5OpenUNIX* | sysv5UnixWare7.[01].[10]* | unixware7* | sco3.2v5.0.[024]*)
+      no_undefined_flag='$wl-z,text'
+      archive_cmds_need_lc=no
+      hardcode_shlibpath_var=no
+      runpath_var='LD_RUN_PATH'
+
+      if test yes = "$GCC"; then
+	archive_cmds='$CC -shared $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='$CC -shared $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	archive_cmds='$CC -G $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='$CC -G $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      fi
+      ;;
+
+    sysv5* | sco3.2v5* | sco5v6*)
+      # Note: We CANNOT use -z defs as we might desire, because we do not
+      # link with -lc, and that would cause any symbols used from libc to
+      # always be unresolved, which means just about no library would
+      # ever link correctly.  If we're not using GNU ld we use -z text
+      # though, which does catch some bad symbols but isn't as heavy-handed
+      # as -z defs.
+      no_undefined_flag='$wl-z,text'
+      allow_undefined_flag='$wl-z,nodefs'
+      archive_cmds_need_lc=no
+      hardcode_shlibpath_var=no
+      hardcode_libdir_flag_spec='$wl-R,$libdir'
+      hardcode_libdir_separator=':'
+      link_all_deplibs=yes
+      export_dynamic_flag_spec='$wl-Bexport'
+      runpath_var='LD_RUN_PATH'
+
+      if test yes = "$GCC"; then
+	archive_cmds='$CC -shared $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='$CC -shared $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	archive_cmds='$CC -G $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='$CC -G $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      fi
+      ;;
+
+    uts4*)
+      archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_shlibpath_var=no
+      ;;
+
+    *)
+      ld_shlibs=no
+      ;;
+    esac
+
+    if test sni = "$host_vendor"; then
+      case $host in
+      sysv4 | sysv4.2uw2* | sysv4.3* | sysv5*)
+	export_dynamic_flag_spec='$wl-Blargedynsym'
+	;;
+      esac
+    fi
+  fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ld_shlibs" >&5
+$as_echo "$ld_shlibs" >&6; }
+test no = "$ld_shlibs" && can_build_shared=no
+
+with_gnu_ld=$with_gnu_ld
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+#
+# Do we need to explicitly link libc?
+#
+case "x$archive_cmds_need_lc" in
+x|xyes)
+  # Assume -lc should be added
+  archive_cmds_need_lc=yes
+
+  if test yes,yes = "$GCC,$enable_shared"; then
+    case $archive_cmds in
+    *'~'*)
+      # FIXME: we may have to deal with multi-command sequences.
+      ;;
+    '$CC '*)
+      # Test whether the compiler implicitly links with -lc since on some
+      # systems, -lgcc has to come before -lc. If gcc already passes -lc
+      # to ld, don't add -lc before -lgcc.
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether -lc should be explicitly linked in" >&5
+$as_echo_n "checking whether -lc should be explicitly linked in... " >&6; }
+if ${lt_cv_archive_cmds_need_lc+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  $RM conftest*
+	echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+
+	if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } 2>conftest.err; then
+	  soname=conftest
+	  lib=conftest
+	  libobjs=conftest.$ac_objext
+	  deplibs=
+	  wl=$lt_prog_compiler_wl
+	  pic_flag=$lt_prog_compiler_pic
+	  compiler_flags=-v
+	  linker_flags=-v
+	  verstring=
+	  output_objdir=.
+	  libname=conftest
+	  lt_save_allow_undefined_flag=$allow_undefined_flag
+	  allow_undefined_flag=
+	  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$archive_cmds 2\>\&1 \| $GREP \" -lc \" \>/dev/null 2\>\&1\""; } >&5
+  (eval $archive_cmds 2\>\&1 \| $GREP \" -lc \" \>/dev/null 2\>\&1) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+	  then
+	    lt_cv_archive_cmds_need_lc=no
+	  else
+	    lt_cv_archive_cmds_need_lc=yes
+	  fi
+	  allow_undefined_flag=$lt_save_allow_undefined_flag
+	else
+	  cat conftest.err 1>&5
+	fi
+	$RM conftest*
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_archive_cmds_need_lc" >&5
+$as_echo "$lt_cv_archive_cmds_need_lc" >&6; }
+      archive_cmds_need_lc=$lt_cv_archive_cmds_need_lc
+      ;;
+    esac
+  fi
+  ;;
+esac
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking dynamic linker characteristics" >&5
+$as_echo_n "checking dynamic linker characteristics... " >&6; }
+
+if test yes = "$GCC"; then
+  case $host_os in
+    darwin*) lt_awk_arg='/^libraries:/,/LR/' ;;
+    *) lt_awk_arg='/^libraries:/' ;;
+  esac
+  case $host_os in
+    mingw* | cegcc*) lt_sed_strip_eq='s|=\([A-Za-z]:\)|\1|g' ;;
+    *) lt_sed_strip_eq='s|=/|/|g' ;;
+  esac
+  lt_search_path_spec=`$CC -print-search-dirs | awk $lt_awk_arg | $SED -e "s/^libraries://" -e $lt_sed_strip_eq`
+  case $lt_search_path_spec in
+  *\;*)
+    # if the path contains ";" then we assume it to be the separator
+    # otherwise default to the standard path separator (i.e. ":") - it is
+    # assumed that no part of a normal pathname contains ";" but that should
+    # okay in the real world where ";" in dirpaths is itself problematic.
+    lt_search_path_spec=`$ECHO "$lt_search_path_spec" | $SED 's/;/ /g'`
+    ;;
+  *)
+    lt_search_path_spec=`$ECHO "$lt_search_path_spec" | $SED "s/$PATH_SEPARATOR/ /g"`
+    ;;
+  esac
+  # Ok, now we have the path, separated by spaces, we can step through it
+  # and add multilib dir if necessary...
+  lt_tmp_lt_search_path_spec=
+  lt_multi_os_dir=/`$CC $CPPFLAGS $CFLAGS $LDFLAGS -print-multi-os-directory 2>/dev/null`
+  # ...but if some path component already ends with the multilib dir we assume
+  # that all is fine and trust -print-search-dirs as is (GCC 4.2? or newer).
+  case "$lt_multi_os_dir; $lt_search_path_spec " in
+  "/; "* | "/.; "* | "/./; "* | *"$lt_multi_os_dir "* | *"$lt_multi_os_dir/ "*)
+    lt_multi_os_dir=
+    ;;
+  esac
+  for lt_sys_path in $lt_search_path_spec; do
+    if test -d "$lt_sys_path$lt_multi_os_dir"; then
+      lt_tmp_lt_search_path_spec="$lt_tmp_lt_search_path_spec $lt_sys_path$lt_multi_os_dir"
+    elif test -n "$lt_multi_os_dir"; then
+      test -d "$lt_sys_path" && \
+	lt_tmp_lt_search_path_spec="$lt_tmp_lt_search_path_spec $lt_sys_path"
+    fi
+  done
+  lt_search_path_spec=`$ECHO "$lt_tmp_lt_search_path_spec" | awk '
+BEGIN {RS = " "; FS = "/|\n";} {
+  lt_foo = "";
+  lt_count = 0;
+  for (lt_i = NF; lt_i > 0; lt_i--) {
+    if ($lt_i != "" && $lt_i != ".") {
+      if ($lt_i == "..") {
+        lt_count++;
+      } else {
+        if (lt_count == 0) {
+          lt_foo = "/" $lt_i lt_foo;
+        } else {
+          lt_count--;
+        }
+      }
+    }
+  }
+  if (lt_foo != "") { lt_freq[lt_foo]++; }
+  if (lt_freq[lt_foo] == 1) { print lt_foo; }
+}'`
+  # AWK program above erroneously prepends '/' to C:/dos/paths
+  # for these hosts.
+  case $host_os in
+    mingw* | cegcc*) lt_search_path_spec=`$ECHO "$lt_search_path_spec" |\
+      $SED 's|/\([A-Za-z]:\)|\1|g'` ;;
+  esac
+  sys_lib_search_path_spec=`$ECHO "$lt_search_path_spec" | $lt_NL2SP`
+else
+  sys_lib_search_path_spec="/lib /usr/lib /usr/local/lib"
+fi
+library_names_spec=
+libname_spec='lib$name'
+soname_spec=
+shrext_cmds=.so
+postinstall_cmds=
+postuninstall_cmds=
+finish_cmds=
+finish_eval=
+shlibpath_var=
+shlibpath_overrides_runpath=unknown
+version_type=none
+dynamic_linker="$host_os ld.so"
+sys_lib_dlsearch_path_spec="/lib /usr/lib"
+need_lib_prefix=unknown
+hardcode_into_libs=no
+
+# when you set need_version to no, make sure it does not cause -set_version
+# flags to be left without arguments
+need_version=unknown
+
+
+
+case $host_os in
+aix3*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname.a'
+  shlibpath_var=LIBPATH
+
+  # AIX 3 has no versioning support, so we append a major version to the name.
+  soname_spec='$libname$release$shared_ext$major'
+  ;;
+
+aix[4-9]*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  hardcode_into_libs=yes
+  if test ia64 = "$host_cpu"; then
+    # AIX 5 supports IA64
+    library_names_spec='$libname$release$shared_ext$major $libname$release$shared_ext$versuffix $libname$shared_ext'
+    shlibpath_var=LD_LIBRARY_PATH
+  else
+    # With GCC up to 2.95.x, collect2 would create an import file
+    # for dependence libraries.  The import file would start with
+    # the line '#! .'.  This would cause the generated library to
+    # depend on '.', always an invalid library.  This was fixed in
+    # development snapshots of GCC prior to 3.0.
+    case $host_os in
+      aix4 | aix4.[01] | aix4.[01].*)
+      if { echo '#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 97)'
+	   echo ' yes '
+	   echo '#endif'; } | $CC -E - | $GREP yes > /dev/null; then
+	:
+      else
+	can_build_shared=no
+      fi
+      ;;
+    esac
+    # Using Import Files as archive members, it is possible to support
+    # filename-based versioning of shared library archives on AIX. While
+    # this would work for both with and without runtime linking, it will
+    # prevent static linking of such archives. So we do filename-based
+    # shared library versioning with .so extension only, which is used
+    # when both runtime linking and shared linking is enabled.
+    # Unfortunately, runtime linking may impact performance, so we do
+    # not want this to be the default eventually. Also, we use the
+    # versioned .so libs for executables only if there is the -brtl
+    # linker flag in LDFLAGS as well, or --with-aix-soname=svr4 only.
+    # To allow for filename-based versioning support, we need to create
+    # libNAME.so.V as an archive file, containing:
+    # *) an Import File, referring to the versioned filename of the
+    #    archive as well as the shared archive member, telling the
+    #    bitwidth (32 or 64) of that shared object, and providing the
+    #    list of exported symbols of that shared object, eventually
+    #    decorated with the 'weak' keyword
+    # *) the shared object with the F_LOADONLY flag set, to really avoid
+    #    it being seen by the linker.
+    # At run time we better use the real file rather than another symlink,
+    # but for link time we create the symlink libNAME.so -> libNAME.so.V
+
+    case $with_aix_soname,$aix_use_runtimelinking in
+    # AIX (on Power*) has no versioning support, so currently we cannot hardcode correct
+    # soname into executable. Probably we can add versioning support to
+    # collect2, so additional links can be useful in future.
+    aix,yes) # traditional libtool
+      dynamic_linker='AIX unversionable lib.so'
+      # If using run time linking (on AIX 4.2 or later) use lib<name>.so
+      # instead of lib<name>.a to let people know that these are not
+      # typical AIX shared libraries.
+      library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+      ;;
+    aix,no) # traditional AIX only
+      dynamic_linker='AIX lib.a(lib.so.V)'
+      # We preserve .a as extension for shared libraries through AIX4.2
+      # and later when we are not doing run time linking.
+      library_names_spec='$libname$release.a $libname.a'
+      soname_spec='$libname$release$shared_ext$major'
+      ;;
+    svr4,*) # full svr4 only
+      dynamic_linker="AIX lib.so.V($shared_archive_member_spec.o)"
+      library_names_spec='$libname$release$shared_ext$major $libname$shared_ext'
+      # We do not specify a path in Import Files, so LIBPATH fires.
+      shlibpath_overrides_runpath=yes
+      ;;
+    *,yes) # both, prefer svr4
+      dynamic_linker="AIX lib.so.V($shared_archive_member_spec.o), lib.a(lib.so.V)"
+      library_names_spec='$libname$release$shared_ext$major $libname$shared_ext'
+      # unpreferred sharedlib libNAME.a needs extra handling
+      postinstall_cmds='test -n "$linkname" || linkname="$realname"~func_stripname "" ".so" "$linkname"~$install_shared_prog "$dir/$func_stripname_result.$libext" "$destdir/$func_stripname_result.$libext"~test -z "$tstripme" || test -z "$striplib" || $striplib "$destdir/$func_stripname_result.$libext"'
+      postuninstall_cmds='for n in $library_names $old_library; do :; done~func_stripname "" ".so" "$n"~test "$func_stripname_result" = "$n" || func_append rmfiles " $odir/$func_stripname_result.$libext"'
+      # We do not specify a path in Import Files, so LIBPATH fires.
+      shlibpath_overrides_runpath=yes
+      ;;
+    *,no) # both, prefer aix
+      dynamic_linker="AIX lib.a(lib.so.V), lib.so.V($shared_archive_member_spec.o)"
+      library_names_spec='$libname$release.a $libname.a'
+      soname_spec='$libname$release$shared_ext$major'
+      # unpreferred sharedlib libNAME.so.V and symlink libNAME.so need extra handling
+      postinstall_cmds='test -z "$dlname" || $install_shared_prog $dir/$dlname $destdir/$dlname~test -z "$tstripme" || test -z "$striplib" || $striplib $destdir/$dlname~test -n "$linkname" || linkname=$realname~func_stripname "" ".a" "$linkname"~(cd "$destdir" && $LN_S -f $dlname $func_stripname_result.so)'
+      postuninstall_cmds='test -z "$dlname" || func_append rmfiles " $odir/$dlname"~for n in $old_library $library_names; do :; done~func_stripname "" ".a" "$n"~func_append rmfiles " $odir/$func_stripname_result.so"'
+      ;;
+    esac
+    shlibpath_var=LIBPATH
+  fi
+  ;;
+
+amigaos*)
+  case $host_cpu in
+  powerpc)
+    # Since July 2007 AmigaOS4 officially supports .so libraries.
+    # When compiling the executable, add -use-dynld -Lsobjs: to the compileline.
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    ;;
+  m68k)
+    library_names_spec='$libname.ixlibrary $libname.a'
+    # Create ${libname}_ixlibrary.a entries in /sys/libs.
+    finish_eval='for lib in `ls $libdir/*.ixlibrary 2>/dev/null`; do libname=`func_echo_all "$lib" | $SED '\''s%^.*/\([^/]*\)\.ixlibrary$%\1%'\''`; $RM /sys/libs/${libname}_ixlibrary.a; $show "cd /sys/libs && $LN_S $lib ${libname}_ixlibrary.a"; cd /sys/libs && $LN_S $lib ${libname}_ixlibrary.a || exit 1; done'
+    ;;
+  esac
+  ;;
+
+beos*)
+  library_names_spec='$libname$shared_ext'
+  dynamic_linker="$host_os ld.so"
+  shlibpath_var=LIBRARY_PATH
+  ;;
+
+bsdi[45]*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  finish_cmds='PATH="\$PATH:/sbin" ldconfig $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  sys_lib_search_path_spec="/shlib /usr/lib /usr/X11/lib /usr/contrib/lib /lib /usr/local/lib"
+  sys_lib_dlsearch_path_spec="/shlib /usr/lib /usr/local/lib"
+  # the default ld.so.conf also contains /usr/contrib/lib and
+  # /usr/X11R6/lib (/usr/X11 is a link to /usr/X11R6), but let us allow
+  # libtool to hard-code these into programs
+  ;;
+
+cygwin* | mingw* | pw32* | cegcc*)
+  version_type=windows
+  shrext_cmds=.dll
+  need_version=no
+  need_lib_prefix=no
+
+  case $GCC,$cc_basename in
+  yes,*)
+    # gcc
+    library_names_spec='$libname.dll.a'
+    # DLL is installed to $(libdir)/../bin by postinstall_cmds
+    postinstall_cmds='base_file=`basename \$file`~
+      dlpath=`$SHELL 2>&1 -c '\''. $dir/'\''\$base_file'\''i; echo \$dlname'\''`~
+      dldir=$destdir/`dirname \$dlpath`~
+      test -d \$dldir || mkdir -p \$dldir~
+      $install_prog $dir/$dlname \$dldir/$dlname~
+      chmod a+x \$dldir/$dlname~
+      if test -n '\''$stripme'\'' && test -n '\''$striplib'\''; then
+        eval '\''$striplib \$dldir/$dlname'\'' || exit \$?;
+      fi'
+    postuninstall_cmds='dldll=`$SHELL 2>&1 -c '\''. $file; echo \$dlname'\''`~
+      dlpath=$dir/\$dldll~
+       $RM \$dlpath'
+    shlibpath_overrides_runpath=yes
+
+    case $host_os in
+    cygwin*)
+      # Cygwin DLLs use 'cyg' prefix rather than 'lib'
+      soname_spec='`echo $libname | sed -e 's/^lib/cyg/'``echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext'
+
+      sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/lib/w32api"
+      ;;
+    mingw* | cegcc*)
+      # MinGW DLLs use traditional 'lib' prefix
+      soname_spec='$libname`echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext'
+      ;;
+    pw32*)
+      # pw32 DLLs use 'pw' prefix rather than 'lib'
+      library_names_spec='`echo $libname | sed -e 's/^lib/pw/'``echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext'
+      ;;
+    esac
+    dynamic_linker='Win32 ld.exe'
+    ;;
+
+  *,cl*)
+    # Native MSVC
+    libname_spec='$name'
+    soname_spec='$libname`echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext'
+    library_names_spec='$libname.dll.lib'
+
+    case $build_os in
+    mingw*)
+      sys_lib_search_path_spec=
+      lt_save_ifs=$IFS
+      IFS=';'
+      for lt_path in $LIB
+      do
+        IFS=$lt_save_ifs
+        # Let DOS variable expansion print the short 8.3 style file name.
+        lt_path=`cd "$lt_path" 2>/dev/null && cmd //C "for %i in (".") do @echo %~si"`
+        sys_lib_search_path_spec="$sys_lib_search_path_spec $lt_path"
+      done
+      IFS=$lt_save_ifs
+      # Convert to MSYS style.
+      sys_lib_search_path_spec=`$ECHO "$sys_lib_search_path_spec" | sed -e 's|\\\\|/|g' -e 's| \\([a-zA-Z]\\):| /\\1|g' -e 's|^ ||'`
+      ;;
+    cygwin*)
+      # Convert to unix form, then to dos form, then back to unix form
+      # but this time dos style (no spaces!) so that the unix form looks
+      # like /cygdrive/c/PROGRA~1:/cygdr...
+      sys_lib_search_path_spec=`cygpath --path --unix "$LIB"`
+      sys_lib_search_path_spec=`cygpath --path --dos "$sys_lib_search_path_spec" 2>/dev/null`
+      sys_lib_search_path_spec=`cygpath --path --unix "$sys_lib_search_path_spec" | $SED -e "s/$PATH_SEPARATOR/ /g"`
+      ;;
+    *)
+      sys_lib_search_path_spec=$LIB
+      if $ECHO "$sys_lib_search_path_spec" | $GREP ';[c-zC-Z]:/' >/dev/null; then
+        # It is most probably a Windows format PATH.
+        sys_lib_search_path_spec=`$ECHO "$sys_lib_search_path_spec" | $SED -e 's/;/ /g'`
+      else
+        sys_lib_search_path_spec=`$ECHO "$sys_lib_search_path_spec" | $SED -e "s/$PATH_SEPARATOR/ /g"`
+      fi
+      # FIXME: find the short name or the path components, as spaces are
+      # common. (e.g. "Program Files" -> "PROGRA~1")
+      ;;
+    esac
+
+    # DLL is installed to $(libdir)/../bin by postinstall_cmds
+    postinstall_cmds='base_file=`basename \$file`~
+      dlpath=`$SHELL 2>&1 -c '\''. $dir/'\''\$base_file'\''i; echo \$dlname'\''`~
+      dldir=$destdir/`dirname \$dlpath`~
+      test -d \$dldir || mkdir -p \$dldir~
+      $install_prog $dir/$dlname \$dldir/$dlname'
+    postuninstall_cmds='dldll=`$SHELL 2>&1 -c '\''. $file; echo \$dlname'\''`~
+      dlpath=$dir/\$dldll~
+       $RM \$dlpath'
+    shlibpath_overrides_runpath=yes
+    dynamic_linker='Win32 link.exe'
+    ;;
+
+  *)
+    # Assume MSVC wrapper
+    library_names_spec='$libname`echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext $libname.lib'
+    dynamic_linker='Win32 ld.exe'
+    ;;
+  esac
+  # FIXME: first we should search . and the directory the executable is in
+  shlibpath_var=PATH
+  ;;
+
+darwin* | rhapsody*)
+  dynamic_linker="$host_os dyld"
+  version_type=darwin
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$major$shared_ext $libname$shared_ext'
+  soname_spec='$libname$release$major$shared_ext'
+  shlibpath_overrides_runpath=yes
+  shlibpath_var=DYLD_LIBRARY_PATH
+  shrext_cmds='`test .$module = .yes && echo .so || echo .dylib`'
+
+  sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/local/lib"
+  sys_lib_dlsearch_path_spec='/usr/local/lib /lib /usr/lib'
+  ;;
+
+dgux*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  ;;
+
+freebsd* | dragonfly*)
+  # DragonFly does not have aout.  When/if they implement a new
+  # versioning mechanism, adjust this.
+  if test -x /usr/bin/objformat; then
+    objformat=`/usr/bin/objformat`
+  else
+    case $host_os in
+    freebsd[23].*) objformat=aout ;;
+    *) objformat=elf ;;
+    esac
+  fi
+  version_type=freebsd-$objformat
+  case $version_type in
+    freebsd-elf*)
+      library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+      soname_spec='$libname$release$shared_ext$major'
+      need_version=no
+      need_lib_prefix=no
+      ;;
+    freebsd-*)
+      library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+      need_version=yes
+      ;;
+  esac
+  shlibpath_var=LD_LIBRARY_PATH
+  case $host_os in
+  freebsd2.*)
+    shlibpath_overrides_runpath=yes
+    ;;
+  freebsd3.[01]* | freebsdelf3.[01]*)
+    shlibpath_overrides_runpath=yes
+    hardcode_into_libs=yes
+    ;;
+  freebsd3.[2-9]* | freebsdelf3.[2-9]* | \
+  freebsd4.[0-5] | freebsdelf4.[0-5] | freebsd4.1.1 | freebsdelf4.1.1)
+    shlibpath_overrides_runpath=no
+    hardcode_into_libs=yes
+    ;;
+  *) # from 4.6 on, and DragonFly
+    shlibpath_overrides_runpath=yes
+    hardcode_into_libs=yes
+    ;;
+  esac
+  ;;
+
+haiku*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  dynamic_linker="$host_os runtime_loader"
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  sys_lib_dlsearch_path_spec='/boot/home/config/lib /boot/common/lib /boot/system/lib'
+  hardcode_into_libs=yes
+  ;;
+
+hpux9* | hpux10* | hpux11*)
+  # Give a soname corresponding to the major version so that dld.sl refuses to
+  # link against other versions.
+  version_type=sunos
+  need_lib_prefix=no
+  need_version=no
+  case $host_cpu in
+  ia64*)
+    shrext_cmds='.so'
+    hardcode_into_libs=yes
+    dynamic_linker="$host_os dld.so"
+    shlibpath_var=LD_LIBRARY_PATH
+    shlibpath_overrides_runpath=yes # Unless +noenvvar is specified.
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    if test 32 = "$HPUX_IA64_MODE"; then
+      sys_lib_search_path_spec="/usr/lib/hpux32 /usr/local/lib/hpux32 /usr/local/lib"
+      sys_lib_dlsearch_path_spec=/usr/lib/hpux32
+    else
+      sys_lib_search_path_spec="/usr/lib/hpux64 /usr/local/lib/hpux64"
+      sys_lib_dlsearch_path_spec=/usr/lib/hpux64
+    fi
+    ;;
+  hppa*64*)
+    shrext_cmds='.sl'
+    hardcode_into_libs=yes
+    dynamic_linker="$host_os dld.sl"
+    shlibpath_var=LD_LIBRARY_PATH # How should we handle SHLIB_PATH
+    shlibpath_overrides_runpath=yes # Unless +noenvvar is specified.
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    sys_lib_search_path_spec="/usr/lib/pa20_64 /usr/ccs/lib/pa20_64"
+    sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
+    ;;
+  *)
+    shrext_cmds='.sl'
+    dynamic_linker="$host_os dld.sl"
+    shlibpath_var=SHLIB_PATH
+    shlibpath_overrides_runpath=no # +s is required to enable SHLIB_PATH
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    ;;
+  esac
+  # HP-UX runs *really* slowly unless shared libraries are mode 555, ...
+  postinstall_cmds='chmod 555 $lib'
+  # or fails outright, so override atomically:
+  install_override_mode=555
+  ;;
+
+interix[3-9]*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  dynamic_linker='Interix 3.x ld.so.1 (PE, like ELF)'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  ;;
+
+irix5* | irix6* | nonstopux*)
+  case $host_os in
+    nonstopux*) version_type=nonstopux ;;
+    *)
+	if test yes = "$lt_cv_prog_gnu_ld"; then
+		version_type=linux # correct to gnu/linux during the next big refactor
+	else
+		version_type=irix
+	fi ;;
+  esac
+  need_lib_prefix=no
+  need_version=no
+  soname_spec='$libname$release$shared_ext$major'
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$release$shared_ext $libname$shared_ext'
+  case $host_os in
+  irix5* | nonstopux*)
+    libsuff= shlibsuff=
+    ;;
+  *)
+    case $LD in # libtool.m4 will add one of these switches to LD
+    *-32|*"-32 "|*-melf32bsmip|*"-melf32bsmip ")
+      libsuff= shlibsuff= libmagic=32-bit;;
+    *-n32|*"-n32 "|*-melf32bmipn32|*"-melf32bmipn32 ")
+      libsuff=32 shlibsuff=N32 libmagic=N32;;
+    *-64|*"-64 "|*-melf64bmip|*"-melf64bmip ")
+      libsuff=64 shlibsuff=64 libmagic=64-bit;;
+    *) libsuff= shlibsuff= libmagic=never-match;;
+    esac
+    ;;
+  esac
+  shlibpath_var=LD_LIBRARY${shlibsuff}_PATH
+  shlibpath_overrides_runpath=no
+  sys_lib_search_path_spec="/usr/lib$libsuff /lib$libsuff /usr/local/lib$libsuff"
+  sys_lib_dlsearch_path_spec="/usr/lib$libsuff /lib$libsuff"
+  hardcode_into_libs=yes
+  ;;
+
+# No shared lib support for Linux oldld, aout, or coff.
+linux*oldld* | linux*aout* | linux*coff*)
+  dynamic_linker=no
+  ;;
+
+linux*android*)
+  version_type=none # Android doesn't support versioned libraries.
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext'
+  soname_spec='$libname$release$shared_ext'
+  finish_cmds=
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+
+  # This implies no fast_install, which is unacceptable.
+  # Some rework will be needed to allow for fast_install
+  # before this can be enabled.
+  hardcode_into_libs=yes
+
+  dynamic_linker='Android linker'
+  # Don't embed -rpath directories since the linker doesn't support them.
+  hardcode_libdir_flag_spec='-L$libdir'
+  ;;
+
+# This must be glibc/ELF.
+linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  finish_cmds='PATH="\$PATH:/sbin" ldconfig -n $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+
+  # Some binutils ld are patched to set DT_RUNPATH
+  if ${lt_cv_shlibpath_overrides_runpath+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  lt_cv_shlibpath_overrides_runpath=no
+    save_LDFLAGS=$LDFLAGS
+    save_libdir=$libdir
+    eval "libdir=/foo; wl=\"$lt_prog_compiler_wl\"; \
+	 LDFLAGS=\"\$LDFLAGS $hardcode_libdir_flag_spec\""
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  if  ($OBJDUMP -p conftest$ac_exeext) 2>/dev/null | grep "RUNPATH.*$libdir" >/dev/null; then :
+  lt_cv_shlibpath_overrides_runpath=yes
+fi
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+    LDFLAGS=$save_LDFLAGS
+    libdir=$save_libdir
+
+fi
+
+  shlibpath_overrides_runpath=$lt_cv_shlibpath_overrides_runpath
+
+  # This implies no fast_install, which is unacceptable.
+  # Some rework will be needed to allow for fast_install
+  # before this can be enabled.
+  hardcode_into_libs=yes
+
+  # Ideally, we could use ldconfig to report *all* directores which are
+  # searched for libraries, however this is still not possible.  Aside from not
+  # being certain /sbin/ldconfig is available, command
+  # 'ldconfig -N -X -v | grep ^/' on 64bit Fedora does not report /usr/lib64,
+  # even though it is searched at run-time.  Try to do the best guess by
+  # appending ld.so.conf contents (and includes) to the search path.
+  if test -f /etc/ld.so.conf; then
+    lt_ld_extra=`awk '/^include / { system(sprintf("cd /etc; cat %s 2>/dev/null", \$2)); skip = 1; } { if (!skip) print \$0; skip = 0; }' < /etc/ld.so.conf | $SED -e 's/#.*//;/^[	 ]*hwcap[	 ]/d;s/[:,	]/ /g;s/=[^=]*$//;s/=[^= ]* / /g;s/"//g;/^$/d' | tr '\n' ' '`
+    sys_lib_dlsearch_path_spec="/lib /usr/lib $lt_ld_extra"
+  fi
+
+  # We used to test for /lib/ld.so.1 and disable shared libraries on
+  # powerpc, because MkLinux only supported shared libraries with the
+  # GNU dynamic linker.  Since this was broken with cross compilers,
+  # most powerpc-linux boxes support dynamic linking these days and
+  # people can always --disable-shared, the test was removed, and we
+  # assume the GNU/Linux dynamic linker is in use.
+  dynamic_linker='GNU/Linux ld.so'
+  ;;
+
+netbsd*)
+  version_type=sunos
+  need_lib_prefix=no
+  need_version=no
+  if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+    finish_cmds='PATH="\$PATH:/sbin" ldconfig -m $libdir'
+    dynamic_linker='NetBSD (a.out) ld.so'
+  else
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    dynamic_linker='NetBSD ld.elf_so'
+  fi
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  hardcode_into_libs=yes
+  ;;
+
+newsos6)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  ;;
+
+*nto* | *qnx*)
+  version_type=qnx
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  dynamic_linker='ldqnx.so'
+  ;;
+
+openbsd* | bitrig*)
+  version_type=sunos
+  sys_lib_dlsearch_path_spec=/usr/lib
+  need_lib_prefix=no
+  if test -z "`echo __ELF__ | $CC -E - | $GREP __ELF__`"; then
+    need_version=no
+  else
+    need_version=yes
+  fi
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+  finish_cmds='PATH="\$PATH:/sbin" ldconfig -m $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  ;;
+
+os2*)
+  libname_spec='$name'
+  version_type=windows
+  shrext_cmds=.dll
+  need_version=no
+  need_lib_prefix=no
+  # OS/2 can only load a DLL with a base name of 8 characters or less.
+  soname_spec='`test -n "$os2dllname" && libname="$os2dllname";
+    v=$($ECHO $release$versuffix | tr -d .-);
+    n=$($ECHO $libname | cut -b -$((8 - ${#v})) | tr . _);
+    $ECHO $n$v`$shared_ext'
+  library_names_spec='${libname}_dll.$libext'
+  dynamic_linker='OS/2 ld.exe'
+  shlibpath_var=BEGINLIBPATH
+  sys_lib_search_path_spec="/lib /usr/lib /usr/local/lib"
+  sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
+  postinstall_cmds='base_file=`basename \$file`~
+    dlpath=`$SHELL 2>&1 -c '\''. $dir/'\''\$base_file'\''i; $ECHO \$dlname'\''`~
+    dldir=$destdir/`dirname \$dlpath`~
+    test -d \$dldir || mkdir -p \$dldir~
+    $install_prog $dir/$dlname \$dldir/$dlname~
+    chmod a+x \$dldir/$dlname~
+    if test -n '\''$stripme'\'' && test -n '\''$striplib'\''; then
+      eval '\''$striplib \$dldir/$dlname'\'' || exit \$?;
+    fi'
+  postuninstall_cmds='dldll=`$SHELL 2>&1 -c '\''. $file; $ECHO \$dlname'\''`~
+    dlpath=$dir/\$dldll~
+    $RM \$dlpath'
+  ;;
+
+osf3* | osf4* | osf5*)
+  version_type=osf
+  need_lib_prefix=no
+  need_version=no
+  soname_spec='$libname$release$shared_ext$major'
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  shlibpath_var=LD_LIBRARY_PATH
+  sys_lib_search_path_spec="/usr/shlib /usr/ccs/lib /usr/lib/cmplrs/cc /usr/lib /usr/local/lib /var/shlib"
+  sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
+  ;;
+
+rdos*)
+  dynamic_linker=no
+  ;;
+
+solaris*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  hardcode_into_libs=yes
+  # ldd complains unless libraries are executable
+  postinstall_cmds='chmod +x $lib'
+  ;;
+
+sunos4*)
+  version_type=sunos
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+  finish_cmds='PATH="\$PATH:/usr/etc" ldconfig $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  if test yes = "$with_gnu_ld"; then
+    need_lib_prefix=no
+  fi
+  need_version=yes
+  ;;
+
+sysv4 | sysv4.3*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  case $host_vendor in
+    sni)
+      shlibpath_overrides_runpath=no
+      need_lib_prefix=no
+      runpath_var=LD_RUN_PATH
+      ;;
+    siemens)
+      need_lib_prefix=no
+      ;;
+    motorola)
+      need_lib_prefix=no
+      need_version=no
+      shlibpath_overrides_runpath=no
+      sys_lib_search_path_spec='/lib /usr/lib /usr/ccs/lib'
+      ;;
+  esac
+  ;;
+
+sysv4*MP*)
+  if test -d /usr/nec; then
+    version_type=linux # correct to gnu/linux during the next big refactor
+    library_names_spec='$libname$shared_ext.$versuffix $libname$shared_ext.$major $libname$shared_ext'
+    soname_spec='$libname$shared_ext.$major'
+    shlibpath_var=LD_LIBRARY_PATH
+  fi
+  ;;
+
+sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX* | sysv4*uw2*)
+  version_type=sco
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  hardcode_into_libs=yes
+  if test yes = "$with_gnu_ld"; then
+    sys_lib_search_path_spec='/usr/local/lib /usr/gnu/lib /usr/ccs/lib /usr/lib /lib'
+  else
+    sys_lib_search_path_spec='/usr/ccs/lib /usr/lib'
+    case $host_os in
+      sco3.2v5*)
+        sys_lib_search_path_spec="$sys_lib_search_path_spec /lib"
+	;;
+    esac
+  fi
+  sys_lib_dlsearch_path_spec='/usr/lib'
+  ;;
+
+tpf*)
+  # TPF is a cross-target only.  Preferred cross-host = GNU/Linux.
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  ;;
+
+uts4*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  ;;
+
+*)
+  dynamic_linker=no
+  ;;
+esac
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $dynamic_linker" >&5
+$as_echo "$dynamic_linker" >&6; }
+test no = "$dynamic_linker" && can_build_shared=no
+
+variables_saved_for_relink="PATH $shlibpath_var $runpath_var"
+if test yes = "$GCC"; then
+  variables_saved_for_relink="$variables_saved_for_relink GCC_EXEC_PREFIX COMPILER_PATH LIBRARY_PATH"
+fi
+
+if test set = "${lt_cv_sys_lib_search_path_spec+set}"; then
+  sys_lib_search_path_spec=$lt_cv_sys_lib_search_path_spec
+fi
+
+if test set = "${lt_cv_sys_lib_dlsearch_path_spec+set}"; then
+  sys_lib_dlsearch_path_spec=$lt_cv_sys_lib_dlsearch_path_spec
+fi
+
+# remember unaugmented sys_lib_dlsearch_path content for libtool script decls...
+configure_time_dlsearch_path=$sys_lib_dlsearch_path_spec
+
+# ... but it needs LT_SYS_LIBRARY_PATH munging for other configure-time code
+func_munge_path_list sys_lib_dlsearch_path_spec "$LT_SYS_LIBRARY_PATH"
+
+# to be used as default LT_SYS_LIBRARY_PATH value in generated libtool
+configure_time_lt_sys_library_path=$LT_SYS_LIBRARY_PATH
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking how to hardcode library paths into programs" >&5
+$as_echo_n "checking how to hardcode library paths into programs... " >&6; }
+hardcode_action=
+if test -n "$hardcode_libdir_flag_spec" ||
+   test -n "$runpath_var" ||
+   test yes = "$hardcode_automatic"; then
+
+  # We can hardcode non-existent directories.
+  if test no != "$hardcode_direct" &&
+     # If the only mechanism to avoid hardcoding is shlibpath_var, we
+     # have to relink, otherwise we might link with an installed library
+     # when we should be linking with a yet-to-be-installed one
+     ## test no != "$_LT_TAGVAR(hardcode_shlibpath_var, )" &&
+     test no != "$hardcode_minus_L"; then
+    # Linking always hardcodes the temporary library directory.
+    hardcode_action=relink
+  else
+    # We can link without hardcoding, and we can hardcode nonexisting dirs.
+    hardcode_action=immediate
+  fi
+else
+  # We cannot hardcode anything, or else we can only hardcode existing
+  # directories.
+  hardcode_action=unsupported
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $hardcode_action" >&5
+$as_echo "$hardcode_action" >&6; }
+
+if test relink = "$hardcode_action" ||
+   test yes = "$inherit_rpath"; then
+  # Fast installation is not supported
+  enable_fast_install=no
+elif test yes = "$shlibpath_overrides_runpath" ||
+     test no = "$enable_shared"; then
+  # Fast installation is not necessary
+  enable_fast_install=needless
+fi
+
+
+
+
+
+
+  if test yes != "$enable_dlopen"; then
+  enable_dlopen=unknown
+  enable_dlopen_self=unknown
+  enable_dlopen_self_static=unknown
+else
+  lt_cv_dlopen=no
+  lt_cv_dlopen_libs=
+
+  case $host_os in
+  beos*)
+    lt_cv_dlopen=load_add_on
+    lt_cv_dlopen_libs=
+    lt_cv_dlopen_self=yes
+    ;;
+
+  mingw* | pw32* | cegcc*)
+    lt_cv_dlopen=LoadLibrary
+    lt_cv_dlopen_libs=
+    ;;
+
+  cygwin*)
+    lt_cv_dlopen=dlopen
+    lt_cv_dlopen_libs=
+    ;;
+
+  darwin*)
+    # if libdl is installed we need to link against it
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dlopen in -ldl" >&5
+$as_echo_n "checking for dlopen in -ldl... " >&6; }
+if ${ac_cv_lib_dl_dlopen+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldl  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dlopen ();
+int
+main ()
+{
+return dlopen ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_dl_dlopen=yes
+else
+  ac_cv_lib_dl_dlopen=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dl_dlopen" >&5
+$as_echo "$ac_cv_lib_dl_dlopen" >&6; }
+if test "x$ac_cv_lib_dl_dlopen" = xyes; then :
+  lt_cv_dlopen=dlopen lt_cv_dlopen_libs=-ldl
+else
+
+    lt_cv_dlopen=dyld
+    lt_cv_dlopen_libs=
+    lt_cv_dlopen_self=yes
+
+fi
+
+    ;;
+
+  tpf*)
+    # Don't try to run any link tests for TPF.  We know it's impossible
+    # because TPF is a cross-compiler, and we know how we open DSOs.
+    lt_cv_dlopen=dlopen
+    lt_cv_dlopen_libs=
+    lt_cv_dlopen_self=no
+    ;;
+
+  *)
+    ac_fn_c_check_func "$LINENO" "shl_load" "ac_cv_func_shl_load"
+if test "x$ac_cv_func_shl_load" = xyes; then :
+  lt_cv_dlopen=shl_load
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for shl_load in -ldld" >&5
+$as_echo_n "checking for shl_load in -ldld... " >&6; }
+if ${ac_cv_lib_dld_shl_load+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldld  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char shl_load ();
+int
+main ()
+{
+return shl_load ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_dld_shl_load=yes
+else
+  ac_cv_lib_dld_shl_load=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dld_shl_load" >&5
+$as_echo "$ac_cv_lib_dld_shl_load" >&6; }
+if test "x$ac_cv_lib_dld_shl_load" = xyes; then :
+  lt_cv_dlopen=shl_load lt_cv_dlopen_libs=-ldld
+else
+  ac_fn_c_check_func "$LINENO" "dlopen" "ac_cv_func_dlopen"
+if test "x$ac_cv_func_dlopen" = xyes; then :
+  lt_cv_dlopen=dlopen
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dlopen in -ldl" >&5
+$as_echo_n "checking for dlopen in -ldl... " >&6; }
+if ${ac_cv_lib_dl_dlopen+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldl  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dlopen ();
+int
+main ()
+{
+return dlopen ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_dl_dlopen=yes
+else
+  ac_cv_lib_dl_dlopen=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dl_dlopen" >&5
+$as_echo "$ac_cv_lib_dl_dlopen" >&6; }
+if test "x$ac_cv_lib_dl_dlopen" = xyes; then :
+  lt_cv_dlopen=dlopen lt_cv_dlopen_libs=-ldl
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dlopen in -lsvld" >&5
+$as_echo_n "checking for dlopen in -lsvld... " >&6; }
+if ${ac_cv_lib_svld_dlopen+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lsvld  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dlopen ();
+int
+main ()
+{
+return dlopen ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_svld_dlopen=yes
+else
+  ac_cv_lib_svld_dlopen=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_svld_dlopen" >&5
+$as_echo "$ac_cv_lib_svld_dlopen" >&6; }
+if test "x$ac_cv_lib_svld_dlopen" = xyes; then :
+  lt_cv_dlopen=dlopen lt_cv_dlopen_libs=-lsvld
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dld_link in -ldld" >&5
+$as_echo_n "checking for dld_link in -ldld... " >&6; }
+if ${ac_cv_lib_dld_dld_link+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldld  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dld_link ();
+int
+main ()
+{
+return dld_link ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_dld_dld_link=yes
+else
+  ac_cv_lib_dld_dld_link=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dld_dld_link" >&5
+$as_echo "$ac_cv_lib_dld_dld_link" >&6; }
+if test "x$ac_cv_lib_dld_dld_link" = xyes; then :
+  lt_cv_dlopen=dld_link lt_cv_dlopen_libs=-ldld
+fi
+
+
+fi
+
+
+fi
+
+
+fi
+
+
+fi
+
+
+fi
+
+    ;;
+  esac
+
+  if test no = "$lt_cv_dlopen"; then
+    enable_dlopen=no
+  else
+    enable_dlopen=yes
+  fi
+
+  case $lt_cv_dlopen in
+  dlopen)
+    save_CPPFLAGS=$CPPFLAGS
+    test yes = "$ac_cv_header_dlfcn_h" && CPPFLAGS="$CPPFLAGS -DHAVE_DLFCN_H"
+
+    save_LDFLAGS=$LDFLAGS
+    wl=$lt_prog_compiler_wl eval LDFLAGS=\"\$LDFLAGS $export_dynamic_flag_spec\"
+
+    save_LIBS=$LIBS
+    LIBS="$lt_cv_dlopen_libs $LIBS"
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether a program can dlopen itself" >&5
+$as_echo_n "checking whether a program can dlopen itself... " >&6; }
+if ${lt_cv_dlopen_self+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  	  if test yes = "$cross_compiling"; then :
+  lt_cv_dlopen_self=cross
+else
+  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
+  lt_status=$lt_dlunknown
+  cat > conftest.$ac_ext <<_LT_EOF
+#line $LINENO "configure"
+#include "confdefs.h"
+
+#if HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif
+
+#include <stdio.h>
+
+#ifdef RTLD_GLOBAL
+#  define LT_DLGLOBAL		RTLD_GLOBAL
+#else
+#  ifdef DL_GLOBAL
+#    define LT_DLGLOBAL		DL_GLOBAL
+#  else
+#    define LT_DLGLOBAL		0
+#  endif
+#endif
+
+/* We may have to define LT_DLLAZY_OR_NOW in the command line if we
+   find out it does not work in some platform. */
+#ifndef LT_DLLAZY_OR_NOW
+#  ifdef RTLD_LAZY
+#    define LT_DLLAZY_OR_NOW		RTLD_LAZY
+#  else
+#    ifdef DL_LAZY
+#      define LT_DLLAZY_OR_NOW		DL_LAZY
+#    else
+#      ifdef RTLD_NOW
+#        define LT_DLLAZY_OR_NOW	RTLD_NOW
+#      else
+#        ifdef DL_NOW
+#          define LT_DLLAZY_OR_NOW	DL_NOW
+#        else
+#          define LT_DLLAZY_OR_NOW	0
+#        endif
+#      endif
+#    endif
+#  endif
+#endif
+
+/* When -fvisibility=hidden is used, assume the code has been annotated
+   correspondingly for the symbols needed.  */
+#if defined __GNUC__ && (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 3))
+int fnord () __attribute__((visibility("default")));
+#endif
+
+int fnord () { return 42; }
+int main ()
+{
+  void *self = dlopen (0, LT_DLGLOBAL|LT_DLLAZY_OR_NOW);
+  int status = $lt_dlunknown;
+
+  if (self)
+    {
+      if (dlsym (self,"fnord"))       status = $lt_dlno_uscore;
+      else
+        {
+	  if (dlsym( self,"_fnord"))  status = $lt_dlneed_uscore;
+          else puts (dlerror ());
+	}
+      /* dlclose (self); */
+    }
+  else
+    puts (dlerror ());
+
+  return status;
+}
+_LT_EOF
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_link\""; } >&5
+  (eval $ac_link) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && test -s "conftest$ac_exeext" 2>/dev/null; then
+    (./conftest; exit; ) >&5 2>/dev/null
+    lt_status=$?
+    case x$lt_status in
+      x$lt_dlno_uscore) lt_cv_dlopen_self=yes ;;
+      x$lt_dlneed_uscore) lt_cv_dlopen_self=yes ;;
+      x$lt_dlunknown|x*) lt_cv_dlopen_self=no ;;
+    esac
+  else :
+    # compilation failed
+    lt_cv_dlopen_self=no
+  fi
+fi
+rm -fr conftest*
+
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_dlopen_self" >&5
+$as_echo "$lt_cv_dlopen_self" >&6; }
+
+    if test yes = "$lt_cv_dlopen_self"; then
+      wl=$lt_prog_compiler_wl eval LDFLAGS=\"\$LDFLAGS $lt_prog_compiler_static\"
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether a statically linked program can dlopen itself" >&5
+$as_echo_n "checking whether a statically linked program can dlopen itself... " >&6; }
+if ${lt_cv_dlopen_self_static+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  	  if test yes = "$cross_compiling"; then :
+  lt_cv_dlopen_self_static=cross
+else
+  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
+  lt_status=$lt_dlunknown
+  cat > conftest.$ac_ext <<_LT_EOF
+#line $LINENO "configure"
+#include "confdefs.h"
+
+#if HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif
+
+#include <stdio.h>
+
+#ifdef RTLD_GLOBAL
+#  define LT_DLGLOBAL		RTLD_GLOBAL
+#else
+#  ifdef DL_GLOBAL
+#    define LT_DLGLOBAL		DL_GLOBAL
+#  else
+#    define LT_DLGLOBAL		0
+#  endif
+#endif
+
+/* We may have to define LT_DLLAZY_OR_NOW in the command line if we
+   find out it does not work in some platform. */
+#ifndef LT_DLLAZY_OR_NOW
+#  ifdef RTLD_LAZY
+#    define LT_DLLAZY_OR_NOW		RTLD_LAZY
+#  else
+#    ifdef DL_LAZY
+#      define LT_DLLAZY_OR_NOW		DL_LAZY
+#    else
+#      ifdef RTLD_NOW
+#        define LT_DLLAZY_OR_NOW	RTLD_NOW
+#      else
+#        ifdef DL_NOW
+#          define LT_DLLAZY_OR_NOW	DL_NOW
+#        else
+#          define LT_DLLAZY_OR_NOW	0
+#        endif
+#      endif
+#    endif
+#  endif
+#endif
+
+/* When -fvisibility=hidden is used, assume the code has been annotated
+   correspondingly for the symbols needed.  */
+#if defined __GNUC__ && (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 3))
+int fnord () __attribute__((visibility("default")));
+#endif
+
+int fnord () { return 42; }
+int main ()
+{
+  void *self = dlopen (0, LT_DLGLOBAL|LT_DLLAZY_OR_NOW);
+  int status = $lt_dlunknown;
+
+  if (self)
+    {
+      if (dlsym (self,"fnord"))       status = $lt_dlno_uscore;
+      else
+        {
+	  if (dlsym( self,"_fnord"))  status = $lt_dlneed_uscore;
+          else puts (dlerror ());
+	}
+      /* dlclose (self); */
+    }
+  else
+    puts (dlerror ());
+
+  return status;
+}
+_LT_EOF
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_link\""; } >&5
+  (eval $ac_link) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && test -s "conftest$ac_exeext" 2>/dev/null; then
+    (./conftest; exit; ) >&5 2>/dev/null
+    lt_status=$?
+    case x$lt_status in
+      x$lt_dlno_uscore) lt_cv_dlopen_self_static=yes ;;
+      x$lt_dlneed_uscore) lt_cv_dlopen_self_static=yes ;;
+      x$lt_dlunknown|x*) lt_cv_dlopen_self_static=no ;;
+    esac
+  else :
+    # compilation failed
+    lt_cv_dlopen_self_static=no
+  fi
+fi
+rm -fr conftest*
+
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $lt_cv_dlopen_self_static" >&5
+$as_echo "$lt_cv_dlopen_self_static" >&6; }
+    fi
+
+    CPPFLAGS=$save_CPPFLAGS
+    LDFLAGS=$save_LDFLAGS
+    LIBS=$save_LIBS
+    ;;
+  esac
+
+  case $lt_cv_dlopen_self in
+  yes|no) enable_dlopen_self=$lt_cv_dlopen_self ;;
+  *) enable_dlopen_self=unknown ;;
+  esac
+
+  case $lt_cv_dlopen_self_static in
+  yes|no) enable_dlopen_self_static=$lt_cv_dlopen_self_static ;;
+  *) enable_dlopen_self_static=unknown ;;
+  esac
+fi
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+striplib=
+old_striplib=
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether stripping libraries is possible" >&5
+$as_echo_n "checking whether stripping libraries is possible... " >&6; }
+if test -n "$STRIP" && $STRIP -V 2>&1 | $GREP "GNU strip" >/dev/null; then
+  test -z "$old_striplib" && old_striplib="$STRIP --strip-debug"
+  test -z "$striplib" && striplib="$STRIP --strip-unneeded"
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+# FIXME - insert some real tests, host_os isn't really good enough
+  case $host_os in
+  darwin*)
+    if test -n "$STRIP"; then
+      striplib="$STRIP -x"
+      old_striplib="$STRIP -S"
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+    else
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+    fi
+    ;;
+  *)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+    ;;
+  esac
+fi
+
+
+
+
+
+
+
+
+
+
+
+
+  # Report what library types will actually be built
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if libtool supports shared libraries" >&5
+$as_echo_n "checking if libtool supports shared libraries... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $can_build_shared" >&5
+$as_echo "$can_build_shared" >&6; }
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to build shared libraries" >&5
+$as_echo_n "checking whether to build shared libraries... " >&6; }
+  test no = "$can_build_shared" && enable_shared=no
+
+  # On AIX, shared libraries and static libraries use the same namespace, and
+  # are all built from PIC.
+  case $host_os in
+  aix3*)
+    test yes = "$enable_shared" && enable_static=no
+    if test -n "$RANLIB"; then
+      archive_cmds="$archive_cmds~\$RANLIB \$lib"
+      postinstall_cmds='$RANLIB $lib'
+    fi
+    ;;
+
+  aix[4-9]*)
+    if test ia64 != "$host_cpu"; then
+      case $enable_shared,$with_aix_soname,$aix_use_runtimelinking in
+      yes,aix,yes) ;;			# shared object as lib.so file only
+      yes,svr4,*) ;;			# shared object as lib.so archive member only
+      yes,*) enable_static=no ;;	# shared object in lib.a archive as well
+      esac
+    fi
+    ;;
+  esac
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $enable_shared" >&5
+$as_echo "$enable_shared" >&6; }
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to build static libraries" >&5
+$as_echo_n "checking whether to build static libraries... " >&6; }
+  # Make sure either enable_shared or enable_static is yes.
+  test yes = "$enable_shared" || enable_static=yes
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $enable_static" >&5
+$as_echo "$enable_static" >&6; }
+
+
+
+
+fi
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+CC=$lt_save_CC
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+        ac_config_commands="$ac_config_commands libtool"
+
+
+
+
+# Only expand once:
+
+
+
+
+# Some awks crash when confronted with pnglibconf.dfa, do a test run now
+# to make sure this doesn't happen
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking that AWK works" >&5
+$as_echo_n "checking that AWK works... " >&6; }
+if ${AWK} -f ${srcdir}/scripts/options.awk out="/dev/null" version=search\
+   ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+   ${srcdir}/pngusr.dfa 1>&2
+then
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: ok" >&5
+$as_echo "ok" >&6; }
+else
+   { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error 1 "failed
+See \`config.log' for more details" "$LINENO" 5; }
+fi
+
+# This is a remnant of the old cc -E validation, where it may have been
+# necessary to use a different preprocessor for .dfn files
+DFNCPP="$CPP"
+
+
+# -Werror cannot be passed to GCC in CFLAGS because configure will fail (it
+# checks the compiler with a program that generates a warning), add the
+# following option to deal with this
+
+# Check whether --enable-werror was given.
+if test "${enable_werror+set}" = set; then :
+  enableval=$enable_werror; test "$enable_werror" = "yes" && enable_werror="-Werror"
+    if test "$enable_werror" != "no"; then
+      sav_CFLAGS="$CFLAGS"
+      CFLAGS="$enable_werror $CFLAGS"
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler allows $enable_werror" >&5
+$as_echo_n "checking if the compiler allows $enable_werror... " >&6; }
+      cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+            int main(int argc, char **argv){
+            return argv[argc-1][0];
+            }
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+         PNG_COPTS="$PNG_COPTS $enable_werror"
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+      CFLAGS="$sav_CFLAGS"
+    fi
+fi
+
+
+# For GCC 5 the default mode for C is -std=gnu11 instead of -std=gnu89
+# In pngpriv.h we request just the POSIX 1003.1 and C89 APIs by defining _POSIX_SOURCE to 1
+# This is incompatible with the new default mode, so we test for that and force the
+# "-std=c89" compiler option:
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if we need to force back C standard to C89" >&5
+$as_echo_n "checking if we need to force back C standard to C89... " >&6; }
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+      #define _POSIX_SOURCE 1
+      #include <stdio.h>
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+else
+
+      if test "x$GCC" != "xyes"; then
+         as_fn_error $? "Forcing back to C89 is required but the flags are only known for GCC" "$LINENO" 5
+      fi
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+   CFLAGS="$CFLAGS -std=c89"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+# Checks for header files.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ANSI C header files" >&5
+$as_echo_n "checking for ANSI C header files... " >&6; }
+if ${ac_cv_header_stdc+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <float.h>
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_header_stdc=yes
+else
+  ac_cv_header_stdc=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+if test $ac_cv_header_stdc = yes; then
+  # SunOS 4.x string.h does not declare mem*, contrary to ANSI.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <string.h>
+
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP "memchr" >/dev/null 2>&1; then :
+
+else
+  ac_cv_header_stdc=no
+fi
+rm -f conftest*
+
+fi
+
+if test $ac_cv_header_stdc = yes; then
+  # ISC 2.0.2 stdlib.h does not declare free, contrary to ANSI.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdlib.h>
+
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP "free" >/dev/null 2>&1; then :
+
+else
+  ac_cv_header_stdc=no
+fi
+rm -f conftest*
+
+fi
+
+if test $ac_cv_header_stdc = yes; then
+  # /bin/cc in Irix-4.0.5 gets non-ANSI ctype macros unless using -ansi.
+  if test "$cross_compiling" = yes; then :
+  :
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <ctype.h>
+#include <stdlib.h>
+#if ((' ' & 0x0FF) == 0x020)
+# define ISLOWER(c) ('a' <= (c) && (c) <= 'z')
+# define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c))
+#else
+# define ISLOWER(c) \
+		   (('a' <= (c) && (c) <= 'i') \
+		     || ('j' <= (c) && (c) <= 'r') \
+		     || ('s' <= (c) && (c) <= 'z'))
+# define TOUPPER(c) (ISLOWER(c) ? ((c) | 0x40) : (c))
+#endif
+
+#define XOR(e, f) (((e) && !(f)) || (!(e) && (f)))
+int
+main ()
+{
+  int i;
+  for (i = 0; i < 256; i++)
+    if (XOR (islower (i), ISLOWER (i))
+	|| toupper (i) != TOUPPER (i))
+      return 2;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+
+else
+  ac_cv_header_stdc=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_header_stdc" >&5
+$as_echo "$ac_cv_header_stdc" >&6; }
+if test $ac_cv_header_stdc = yes; then
+
+$as_echo "#define STDC_HEADERS 1" >>confdefs.h
+
+fi
+
+
+# Checks for typedefs, structures, and compiler characteristics.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for an ANSI C-conforming const" >&5
+$as_echo_n "checking for an ANSI C-conforming const... " >&6; }
+if ${ac_cv_c_const+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+#ifndef __cplusplus
+  /* Ultrix mips cc rejects this sort of thing.  */
+  typedef int charset[2];
+  const charset cs = { 0, 0 };
+  /* SunOS 4.1.1 cc rejects this.  */
+  char const *const *pcpcc;
+  char **ppc;
+  /* NEC SVR4.0.2 mips cc rejects this.  */
+  struct point {int x, y;};
+  static struct point const zero = {0,0};
+  /* AIX XL C 1.02.0.0 rejects this.
+     It does not let you subtract one const X* pointer from another in
+     an arm of an if-expression whose if-part is not a constant
+     expression */
+  const char *g = "string";
+  pcpcc = &g + (g ? g-g : 0);
+  /* HPUX 7.0 cc rejects these. */
+  ++pcpcc;
+  ppc = (char**) pcpcc;
+  pcpcc = (char const *const *) ppc;
+  { /* SCO 3.2v4 cc rejects this sort of thing.  */
+    char tx;
+    char *t = &tx;
+    char const *s = 0 ? (char *) 0 : (char const *) 0;
+
+    *t++ = 0;
+    if (s) return 0;
+  }
+  { /* Someone thinks the Sun supposedly-ANSI compiler will reject this.  */
+    int x[] = {25, 17};
+    const int *foo = &x[0];
+    ++foo;
+  }
+  { /* Sun SC1.0 ANSI compiler rejects this -- but not the above. */
+    typedef const int *iptr;
+    iptr p = 0;
+    ++p;
+  }
+  { /* AIX XL C 1.02.0.0 rejects this sort of thing, saying
+       "k.c", line 2.27: 1506-025 (S) Operand must be a modifiable lvalue. */
+    struct s { int j; const int *ap[3]; } bx;
+    struct s *b = &bx; b->j = 5;
+  }
+  { /* ULTRIX-32 V3.1 (Rev 9) vcc rejects this */
+    const int foo = 10;
+    if (!foo) return 0;
+  }
+  return !cs[0] && !zero.x;
+#endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_c_const=yes
+else
+  ac_cv_c_const=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_c_const" >&5
+$as_echo "$ac_cv_c_const" >&6; }
+if test $ac_cv_c_const = no; then
+
+$as_echo "#define const /**/" >>confdefs.h
+
+fi
+
+ac_fn_c_check_type "$LINENO" "size_t" "ac_cv_type_size_t" "$ac_includes_default"
+if test "x$ac_cv_type_size_t" = xyes; then :
+
+else
+
+cat >>confdefs.h <<_ACEOF
+#define size_t unsigned int
+_ACEOF
+
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether struct tm is in sys/time.h or time.h" >&5
+$as_echo_n "checking whether struct tm is in sys/time.h or time.h... " >&6; }
+if ${ac_cv_struct_tm+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/types.h>
+#include <time.h>
+
+int
+main ()
+{
+struct tm tm;
+				     int *p = &tm.tm_sec;
+				     return !p;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_struct_tm=time.h
+else
+  ac_cv_struct_tm=sys/time.h
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_struct_tm" >&5
+$as_echo "$ac_cv_struct_tm" >&6; }
+if test $ac_cv_struct_tm = sys/time.h; then
+
+$as_echo "#define TM_IN_SYS_TIME 1" >>confdefs.h
+
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for C/C++ restrict keyword" >&5
+$as_echo_n "checking for C/C++ restrict keyword... " >&6; }
+if ${ac_cv_c_restrict+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_c_restrict=no
+   # The order here caters to the fact that C++ does not require restrict.
+   for ac_kw in __restrict __restrict__ _Restrict restrict; do
+     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+typedef int * int_ptr;
+	int foo (int_ptr $ac_kw ip) {
+	return ip[0];
+       }
+int
+main ()
+{
+int s[1];
+	int * $ac_kw t = s;
+	t[0] = 0;
+	return foo(t)
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_c_restrict=$ac_kw
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+     test "$ac_cv_c_restrict" != no && break
+   done
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_c_restrict" >&5
+$as_echo "$ac_cv_c_restrict" >&6; }
+
+ case $ac_cv_c_restrict in
+   restrict) ;;
+   no) $as_echo "#define restrict /**/" >>confdefs.h
+ ;;
+   *)  cat >>confdefs.h <<_ACEOF
+#define restrict $ac_cv_c_restrict
+_ACEOF
+ ;;
+ esac
+
+
+# Checks for library functions.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for working strtod" >&5
+$as_echo_n "checking for working strtod... " >&6; }
+if ${ac_cv_func_strtod+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test "$cross_compiling" = yes; then :
+  ac_cv_func_strtod=no
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+$ac_includes_default
+#ifndef strtod
+double strtod ();
+#endif
+int
+main()
+{
+  {
+    /* Some versions of Linux strtod mis-parse strings with leading '+'.  */
+    char *string = " +69";
+    char *term;
+    double value;
+    value = strtod (string, &term);
+    if (value != 69 || term != (string + 4))
+      return 1;
+  }
+
+  {
+    /* Under Solaris 2.4, strtod returns the wrong value for the
+       terminating character under some conditions.  */
+    char *string = "NaN";
+    char *term;
+    strtod (string, &term);
+    if (term != string && *(term - 1) == 0)
+      return 1;
+  }
+  return 0;
+}
+
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+  ac_cv_func_strtod=yes
+else
+  ac_cv_func_strtod=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_strtod" >&5
+$as_echo "$ac_cv_func_strtod" >&6; }
+if test $ac_cv_func_strtod = no; then
+  case " $LIBOBJS " in
+  *" strtod.$ac_objext "* ) ;;
+  *) LIBOBJS="$LIBOBJS strtod.$ac_objext"
+ ;;
+esac
+
+ac_fn_c_check_func "$LINENO" "pow" "ac_cv_func_pow"
+if test "x$ac_cv_func_pow" = xyes; then :
+
+fi
+
+if test $ac_cv_func_pow = no; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for pow in -lm" >&5
+$as_echo_n "checking for pow in -lm... " >&6; }
+if ${ac_cv_lib_m_pow+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lm  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char pow ();
+int
+main ()
+{
+return pow ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_m_pow=yes
+else
+  ac_cv_lib_m_pow=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_m_pow" >&5
+$as_echo "$ac_cv_lib_m_pow" >&6; }
+if test "x$ac_cv_lib_m_pow" = xyes; then :
+  POW_LIB=-lm
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: cannot find library containing definition of pow" >&5
+$as_echo "$as_me: WARNING: cannot find library containing definition of pow" >&2;}
+fi
+
+fi
+
+fi
+
+for ac_func in pow
+do :
+  ac_fn_c_check_func "$LINENO" "pow" "ac_cv_func_pow"
+if test "x$ac_cv_func_pow" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_POW 1
+_ACEOF
+
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for pow in -lm" >&5
+$as_echo_n "checking for pow in -lm... " >&6; }
+if ${ac_cv_lib_m_pow+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lm  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char pow ();
+int
+main ()
+{
+return pow ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_m_pow=yes
+else
+  ac_cv_lib_m_pow=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_m_pow" >&5
+$as_echo "$ac_cv_lib_m_pow" >&6; }
+if test "x$ac_cv_lib_m_pow" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBM 1
+_ACEOF
+
+  LIBS="-lm $LIBS"
+
+else
+  as_fn_error $? "cannot find pow" "$LINENO" 5
+fi
+
+fi
+done
+
+
+# Some later POSIX 1003.1 functions are required for test programs, failure here
+# is soft (the corresponding test program is not built).
+ac_fn_c_check_func "$LINENO" "clock_gettime" "ac_cv_func_clock_gettime"
+if test "x$ac_cv_func_clock_gettime" = xyes; then :
+
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: not building timepng" >&5
+$as_echo "$as_me: WARNING: not building timepng" >&2;}
+fi
+
+ if test "$ac_cv_func_clock_gettime" = "yes"; then
+  HAVE_CLOCK_GETTIME_TRUE=
+  HAVE_CLOCK_GETTIME_FALSE='#'
+else
+  HAVE_CLOCK_GETTIME_TRUE='#'
+  HAVE_CLOCK_GETTIME_FALSE=
+fi
+
+
+
+# Check whether --with-zlib-prefix was given.
+if test "${with_zlib_prefix+set}" = set; then :
+  withval=$with_zlib_prefix; ZPREFIX=${withval}
+else
+  ZPREFIX='z_'
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for zlibVersion in -lz" >&5
+$as_echo_n "checking for zlibVersion in -lz... " >&6; }
+if ${ac_cv_lib_z_zlibVersion+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lz  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char zlibVersion ();
+int
+main ()
+{
+return zlibVersion ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_z_zlibVersion=yes
+else
+  ac_cv_lib_z_zlibVersion=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_z_zlibVersion" >&5
+$as_echo "$ac_cv_lib_z_zlibVersion" >&6; }
+if test "x$ac_cv_lib_z_zlibVersion" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBZ 1
+_ACEOF
+
+  LIBS="-lz $LIBS"
+
+else
+  as_ac_Lib=`$as_echo "ac_cv_lib_z_${ZPREFIX}zlibVersion" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ${ZPREFIX}zlibVersion in -lz" >&5
+$as_echo_n "checking for ${ZPREFIX}zlibVersion in -lz... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lz  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char ${ZPREFIX}zlibVersion ();
+int
+main ()
+{
+return ${ZPREFIX}zlibVersion ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  eval "$as_ac_Lib=yes"
+else
+  eval "$as_ac_Lib=no"
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+eval ac_res=\$$as_ac_Lib
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBZ 1
+_ACEOF
+
+  LIBS="-lz $LIBS"
+
+else
+  as_fn_error $? "zlib not installed" "$LINENO" 5
+fi
+
+fi
+
+
+# The following is for pngvalid, to ensure it catches FP errors even on
+# platforms that don't enable FP exceptions, the function appears in the math
+# library (typically), it's not an error if it is not found.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for feenableexcept in -lm" >&5
+$as_echo_n "checking for feenableexcept in -lm... " >&6; }
+if ${ac_cv_lib_m_feenableexcept+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lm  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char feenableexcept ();
+int
+main ()
+{
+return feenableexcept ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_m_feenableexcept=yes
+else
+  ac_cv_lib_m_feenableexcept=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_m_feenableexcept" >&5
+$as_echo "$ac_cv_lib_m_feenableexcept" >&6; }
+if test "x$ac_cv_lib_m_feenableexcept" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBM 1
+_ACEOF
+
+  LIBS="-lm $LIBS"
+
+fi
+
+for ac_func in feenableexcept
+do :
+  ac_fn_c_check_func "$LINENO" "feenableexcept" "ac_cv_func_feenableexcept"
+if test "x$ac_cv_func_feenableexcept" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_FEENABLEEXCEPT 1
+_ACEOF
+
+fi
+done
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if using Solaris linker" >&5
+$as_echo_n "checking if using Solaris linker... " >&6; }
+SLD=`$LD --version 2>&1 | grep Solaris`
+if test "$SLD"; then
+    have_solaris_ld=yes
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+    have_solaris_ld=no
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+ if test "$have_solaris_ld" = "yes"; then
+  HAVE_SOLARIS_LD_TRUE=
+  HAVE_SOLARIS_LD_FALSE='#'
+else
+  HAVE_SOLARIS_LD_TRUE='#'
+  HAVE_SOLARIS_LD_FALSE=
+fi
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if libraries can be versioned" >&5
+$as_echo_n "checking if libraries can be versioned... " >&6; }
+# Special case for PE/COFF platforms: ld reports
+# support for version-script, but doesn't actually
+# DO anything with it.
+case $host in
+*cygwin* | *mingw32* | *interix* )
+    have_ld_version_script=no
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+;;
+* )
+
+if test "$have_solaris_ld" = "yes"; then
+    GLD=`$LD --help < /dev/null 2>&1 | grep 'M mapfile'`
+else
+    GLD=`$LD --help < /dev/null 2>/dev/null | grep version-script`
+fi
+
+if test "$GLD"; then
+    have_ld_version_script=yes
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+    have_ld_version_script=no
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: *** You have not enabled versioned symbols." >&5
+$as_echo "$as_me: WARNING: *** You have not enabled versioned symbols." >&2;}
+fi
+;;
+esac
+
+ if test "$have_ld_version_script" = "yes"; then
+  HAVE_LD_VERSION_SCRIPT_TRUE=
+  HAVE_LD_VERSION_SCRIPT_FALSE='#'
+else
+  HAVE_LD_VERSION_SCRIPT_TRUE='#'
+  HAVE_LD_VERSION_SCRIPT_FALSE=
+fi
+
+
+if test "$have_ld_version_script" = "yes"; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for symbol prefix" >&5
+$as_echo_n "checking for symbol prefix... " >&6; }
+    SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
+                  | ${CPP-${CC-gcc} -E} - 2>&1 \
+                  | ${EGREP-grep} "^PREFIX=" \
+                  | ${SED-sed} -e "s:^PREFIX=::" -e "s:__USER_LABEL_PREFIX__::"`
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $SYMBOL_PREFIX" >&5
+$as_echo "$SYMBOL_PREFIX" >&6; }
+fi
+
+# Substitutions for .in files
+
+
+
+
+
+# Additional arguments (and substitutions)
+# Allow the pkg-config directory to be set
+
+# Check whether --with-pkgconfigdir was given.
+if test "${with_pkgconfigdir+set}" = set; then :
+  withval=$with_pkgconfigdir; pkgconfigdir=${withval}
+else
+  pkgconfigdir='${libdir}/pkgconfig'
+fi
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: pkgconfig directory is ${pkgconfigdir}" >&5
+$as_echo "$as_me: pkgconfig directory is ${pkgconfigdir}" >&6;}
+
+# Make the *-config binary config scripts optional
+
+# Check whether --with-binconfigs was given.
+if test "${with_binconfigs+set}" = set; then :
+  withval=$with_binconfigs; if test "${withval}" = no; then
+      binconfigs=
+      { $as_echo "$as_me:${as_lineno-$LINENO}: libpng-config scripts will not be built" >&5
+$as_echo "$as_me: libpng-config scripts will not be built" >&6;}
+    else
+      binconfigs='${binconfigs}'
+    fi
+else
+  binconfigs='${binconfigs}'
+fi
+
+
+
+# Support for prefixes to the API function names; this will generate defines
+# at the start of the build to rename exported library functions
+
+# Check whether --with-libpng-prefix was given.
+if test "${with_libpng_prefix+set}" = set; then :
+  withval=$with_libpng_prefix; if test "${withval:-no}" != "no"; then
+      PNG_PREFIX=${withval}
+
+    fi
+fi
+
+ if test "${with_libpng_prefix:-no}" != "no"; then
+  DO_PNG_PREFIX_TRUE=
+  DO_PNG_PREFIX_FALSE='#'
+else
+  DO_PNG_PREFIX_TRUE='#'
+  DO_PNG_PREFIX_FALSE=
+fi
+
+
+# Control over what links are made for installed files.  Versioned files are
+# always installed, when the following options are turned on corresponding
+# unversioned links are also created (normally as symbolic links):
+# Check whether --enable-unversioned-links was given.
+if test "${enable_unversioned_links+set}" = set; then :
+  enableval=$enable_unversioned_links;
+fi
+
+
+# The AM_CONDITIONAL test is written so that the default is enabled;
+# --disable-unversioned-links must be given to turn the option off.
+ if test "$enable_unversioned_links" != "no"; then
+  DO_INSTALL_LINKS_TRUE=
+  DO_INSTALL_LINKS_FALSE='#'
+else
+  DO_INSTALL_LINKS_TRUE='#'
+  DO_INSTALL_LINKS_FALSE=
+fi
+
+
+# Check whether --enable-unversioned-libpng-pc was given.
+if test "${enable_unversioned_libpng_pc+set}" = set; then :
+  enableval=$enable_unversioned_libpng_pc;
+fi
+
+ if test "$enable_unversioned_libpng_pc" != "no"; then
+  DO_INSTALL_LIBPNG_PC_TRUE=
+  DO_INSTALL_LIBPNG_PC_FALSE='#'
+else
+  DO_INSTALL_LIBPNG_PC_TRUE='#'
+  DO_INSTALL_LIBPNG_PC_FALSE=
+fi
+
+
+# Check whether --enable-unversioned-libpng-config was given.
+if test "${enable_unversioned_libpng_config+set}" = set; then :
+  enableval=$enable_unversioned_libpng_config;
+fi
+
+ if test "$enable_unversioned_libpng_config" != "no"; then
+  DO_INSTALL_LIBPNG_CONFIG_TRUE=
+  DO_INSTALL_LIBPNG_CONFIG_FALSE='#'
+else
+  DO_INSTALL_LIBPNG_CONFIG_TRUE='#'
+  DO_INSTALL_LIBPNG_CONFIG_FALSE=
+fi
+
+
+# HOST SPECIFIC OPTIONS
+# =====================
+#
+# DEFAULT
+# =======
+#
+# Check whether --enable-hardware-optimizations was given.
+if test "${enable_hardware_optimizations+set}" = set; then :
+  enableval=$enable_hardware_optimizations; case "$enableval" in
+      no|off)
+         # disable hardware optimization on all systems:
+         enable_arm_neon=no
+
+$as_echo "#define PNG_ARM_NEON_OPT 0" >>confdefs.h
+
+         enable_mips_msa=no
+
+$as_echo "#define PNG_MIPS_MSA_OPT 0" >>confdefs.h
+
+         enable_powerpc_vsx=no
+
+$as_echo "#define PNG_POWERPC_VSX_OPT 0" >>confdefs.h
+
+         enable_intel_sse=no
+
+$as_echo "#define PNG_INTEL_SSE_OPT 0" >>confdefs.h
+
+         ;;
+      *)
+         # allow enabling hardware optimization on any system:
+         case "$host_cpu" in
+            arm*|aarch64*)
+              enable_arm_neon=yes
+
+$as_echo "#define PNG_ARM_NEON_OPT 0" >>confdefs.h
+
+              ;;
+            mipsel*|mips64el*)
+              enable_mips_msa=yes
+
+$as_echo "#define PNG_MIPS_MSA_OPT 0" >>confdefs.h
+
+              ;;
+            i?86|x86_64)
+              enable_intel_sse=yes
+
+$as_echo "#define PNG_INTEL_SSE_OPT 1" >>confdefs.h
+
+              ;;
+            powerpc*|ppc64*)
+              enable_powerpc_vsx=yes
+
+$as_echo "#define PNG_POWERPC_VSX_OPT 2" >>confdefs.h
+
+              ;;
+         esac
+         ;;
+   esac
+fi
+
+
+# ARM
+# ===
+#
+# ARM NEON (SIMD) support.
+
+# Check whether --enable-arm-neon was given.
+if test "${enable_arm_neon+set}" = set; then :
+  enableval=$enable_arm_neon; case "$enableval" in
+      no|off)
+         # disable the default enabling on __ARM_NEON__ systems:
+
+$as_echo "#define PNG_ARM_NEON_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the assembler files below:
+         enable_arm_neon=no;;
+      check)
+
+$as_echo "#define PNG_ARM_NEON_CHECK_SUPPORTED /**/" >>confdefs.h
+;;
+      api)
+
+$as_echo "#define PNG_ARM_NEON_API_SUPPORTED /**/" >>confdefs.h
+;;
+      yes|on)
+
+$as_echo "#define PNG_ARM_NEON_OPT 2" >>confdefs.h
+
+         { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: --enable-arm-neon: please specify 'check' or 'api', if
+            you want the optimizations unconditionally pass -mfpu=neon
+            to the compiler." >&5
+$as_echo "$as_me: WARNING: --enable-arm-neon: please specify 'check' or 'api', if
+            you want the optimizations unconditionally pass -mfpu=neon
+            to the compiler." >&2;};;
+      *)
+         as_fn_error $? "--enable-arm-neon=${enable_arm_neon}: invalid value" "$LINENO" 5
+   esac
+fi
+
+
+# Add ARM specific files to all builds where the host_cpu is arm ('arm*') or
+# where ARM optimizations were explicitly requested (this allows a fallback if a
+# future host CPU does not match 'arm*')
+
+ if test "$enable_arm_neon" != 'no' &&
+    case "$host_cpu" in
+      arm*|aarch64*) :;;
+      *)    test "$enable_arm_neon" != '';;
+    esac; then
+  PNG_ARM_NEON_TRUE=
+  PNG_ARM_NEON_FALSE='#'
+else
+  PNG_ARM_NEON_TRUE='#'
+  PNG_ARM_NEON_FALSE=
+fi
+
+
+# MIPS
+# ===
+#
+# MIPS MSA (SIMD) support.
+
+# Check whether --enable-mips-msa was given.
+if test "${enable_mips_msa+set}" = set; then :
+  enableval=$enable_mips_msa; case "$enableval" in
+      no|off)
+         # disable the default enabling on __mips_msa systems:
+
+$as_echo "#define PNG_MIPS_MSA_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the assembler files below:
+         enable_mips_msa=no;;
+      check)
+
+$as_echo "#define PNG_MIPS_MSA_CHECK_SUPPORTED /**/" >>confdefs.h
+;;
+      api)
+
+$as_echo "#define PNG_MIPS_MSA_API_SUPPORTED /**/" >>confdefs.h
+;;
+      yes|on)
+
+$as_echo "#define PNG_MIPS_MSA_OPT 2" >>confdefs.h
+
+         { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: --enable-mips-msa: please specify 'check' or 'api', if
+            you want the optimizations unconditionally pass '-mmsa -mfp64'
+            to the compiler." >&5
+$as_echo "$as_me: WARNING: --enable-mips-msa: please specify 'check' or 'api', if
+            you want the optimizations unconditionally pass '-mmsa -mfp64'
+            to the compiler." >&2;};;
+      *)
+         as_fn_error $? "--enable-mips-msa=${enable_mips_msa}: invalid value" "$LINENO" 5
+   esac
+fi
+
+
+# Add MIPS specific files to all builds where the host_cpu is mips ('mips*') or
+# where MIPS optimizations were explicitly requested (this allows a fallback if a
+# future host CPU does not match 'mips*')
+
+ if test "$enable_mips_msa" != 'no' &&
+    case "$host_cpu" in
+      mipsel*|mips64el*) :;;
+    esac; then
+  PNG_MIPS_MSA_TRUE=
+  PNG_MIPS_MSA_FALSE='#'
+else
+  PNG_MIPS_MSA_TRUE='#'
+  PNG_MIPS_MSA_FALSE=
+fi
+
+
+# INTEL
+# =====
+#
+# INTEL SSE (SIMD) support.
+
+# Check whether --enable-intel-sse was given.
+if test "${enable_intel_sse+set}" = set; then :
+  enableval=$enable_intel_sse; case "$enableval" in
+      no|off)
+         # disable the default enabling:
+
+$as_echo "#define PNG_INTEL_SSE_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the assembler files below:
+         enable_intel_sse=no;;
+      yes|on)
+
+$as_echo "#define PNG_INTEL_SSE_OPT 1" >>confdefs.h
+;;
+      *)
+         as_fn_error $? "--enable-intel-sse=${enable_intel_sse}: invalid value" "$LINENO" 5
+   esac
+fi
+
+
+# Add Intel specific files to all builds where the host_cpu is Intel ('x86*')
+# or where Intel optimizations were explicitly requested (this allows a
+# fallback if a future host CPU does not match 'x86*')
+ if test "$enable_intel_sse" != 'no' &&
+    case "$host_cpu" in
+      i?86|x86_64) :;;
+      *)    test "$enable_intel_sse" != '';;
+    esac; then
+  PNG_INTEL_SSE_TRUE=
+  PNG_INTEL_SSE_FALSE='#'
+else
+  PNG_INTEL_SSE_TRUE='#'
+  PNG_INTEL_SSE_FALSE=
+fi
+
+
+# PowerPC
+# ===
+#
+# PowerPC VSX (SIMD) support.
+
+# Check whether --enable-powerpc-vsx was given.
+if test "${enable_powerpc_vsx+set}" = set; then :
+  enableval=$enable_powerpc_vsx; case "$enableval" in
+      no|off)
+         # disable the default enabling on __ppc64__ systems:
+
+$as_echo "#define PNG_POWERPC_VSX_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the platform specific files below:
+         enable_powerpc_vsx=no;;
+      check)
+
+$as_echo "#define PNG_POWERPC_VSX_CHECK_SUPPORTED /**/" >>confdefs.h
+
+         { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: --enable-powerpc-vsx Please check contrib/powerpc/README file
+            for the list of supported OSes." >&5
+$as_echo "$as_me: WARNING: --enable-powerpc-vsx Please check contrib/powerpc/README file
+            for the list of supported OSes." >&2;};;
+      api)
+
+$as_echo "#define PNG_POWERPC_VSX_API_SUPPORTED /**/" >>confdefs.h
+;;
+      yes|on)
+
+$as_echo "#define PNG_POWERPC_VSX_OPT 2" >>confdefs.h
+
+         { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: --enable-powerpc-vsx: please specify 'check' or 'api', if
+            you want the optimizations unconditionally pass '-maltivec -mvsx'
+            or '-mcpu=power8'to the compiler." >&5
+$as_echo "$as_me: WARNING: --enable-powerpc-vsx: please specify 'check' or 'api', if
+            you want the optimizations unconditionally pass '-maltivec -mvsx'
+            or '-mcpu=power8'to the compiler." >&2;};;
+      *)
+         as_fn_error $? "--enable-powerpc-vsx=${enable_powerpc_vsx}: invalid value" "$LINENO" 5
+   esac
+fi
+
+
+# Add PowerPC specific files to all builds where the host_cpu is powerpc('powerpc*') or
+# where POWERPC optimizations were explicitly requested (this allows a fallback if a
+# future host CPU does not match 'powerpc*')
+
+ if test "$enable_powerpc_vsx" != 'no' &&
+    case "$host_cpu" in
+      powerpc*|ppc64*) :;;
+    esac; then
+  PNG_POWERPC_VSX_TRUE=
+  PNG_POWERPC_VSX_FALSE='#'
+else
+  PNG_POWERPC_VSX_TRUE='#'
+  PNG_POWERPC_VSX_FALSE=
+fi
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: Extra options for compiler: $PNG_COPTS" >&5
+$as_echo "$as_me: Extra options for compiler: $PNG_COPTS" >&6;}
+
+# Config files, substituting as above
+ac_config_files="$ac_config_files Makefile libpng.pc:libpng.pc.in"
+
+ac_config_files="$ac_config_files libpng-config:libpng-config.in"
+
+
+cat >confcache <<\_ACEOF
+# This file is a shell script that caches the results of configure
+# tests run on this system so they can be shared between configure
+# scripts and configure runs, see configure's option --config-cache.
+# It is not useful on other systems.  If it contains results you don't
+# want to keep, you may remove or edit it.
+#
+# config.status only pays attention to the cache file if you give it
+# the --recheck option to rerun configure.
+#
+# `ac_cv_env_foo' variables (set or unset) will be overridden when
+# loading this file, other *unset* `ac_cv_foo' will be assigned the
+# following values.
+
+_ACEOF
+
+# The following way of writing the cache mishandles newlines in values,
+# but we know of no workaround that is simple, portable, and efficient.
+# So, we kill variables containing newlines.
+# Ultrix sh set writes to stderr and can't be redirected directly,
+# and sets the high bit in the cache file unless we assign to the vars.
+(
+  for ac_var in `(set) 2>&1 | sed -n 's/^\([a-zA-Z_][a-zA-Z0-9_]*\)=.*/\1/p'`; do
+    eval ac_val=\$$ac_var
+    case $ac_val in #(
+    *${as_nl}*)
+      case $ac_var in #(
+      *_cv_*) { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
+$as_echo "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
+      esac
+      case $ac_var in #(
+      _ | IFS | as_nl) ;; #(
+      BASH_ARGV | BASH_SOURCE) eval $ac_var= ;; #(
+      *) { eval $ac_var=; unset $ac_var;} ;;
+      esac ;;
+    esac
+  done
+
+  (set) 2>&1 |
+    case $as_nl`(ac_space=' '; set) 2>&1` in #(
+    *${as_nl}ac_space=\ *)
+      # `set' does not quote correctly, so add quotes: double-quote
+      # substitution turns \\\\ into \\, and sed turns \\ into \.
+      sed -n \
+	"s/'/'\\\\''/g;
+	  s/^\\([_$as_cr_alnum]*_cv_[_$as_cr_alnum]*\\)=\\(.*\\)/\\1='\\2'/p"
+      ;; #(
+    *)
+      # `set' quotes correctly as required by POSIX, so do not add quotes.
+      sed -n "/^[_$as_cr_alnum]*_cv_[_$as_cr_alnum]*=/p"
+      ;;
+    esac |
+    sort
+) |
+  sed '
+     /^ac_cv_env_/b end
+     t clear
+     :clear
+     s/^\([^=]*\)=\(.*[{}].*\)$/test "${\1+set}" = set || &/
+     t end
+     s/^\([^=]*\)=\(.*\)$/\1=${\1=\2}/
+     :end' >>confcache
+if diff "$cache_file" confcache >/dev/null 2>&1; then :; else
+  if test -w "$cache_file"; then
+    if test "x$cache_file" != "x/dev/null"; then
+      { $as_echo "$as_me:${as_lineno-$LINENO}: updating cache $cache_file" >&5
+$as_echo "$as_me: updating cache $cache_file" >&6;}
+      if test ! -f "$cache_file" || test -h "$cache_file"; then
+	cat confcache >"$cache_file"
+      else
+        case $cache_file in #(
+        */* | ?:*)
+	  mv -f confcache "$cache_file"$$ &&
+	  mv -f "$cache_file"$$ "$cache_file" ;; #(
+        *)
+	  mv -f confcache "$cache_file" ;;
+	esac
+      fi
+    fi
+  else
+    { $as_echo "$as_me:${as_lineno-$LINENO}: not updating unwritable cache $cache_file" >&5
+$as_echo "$as_me: not updating unwritable cache $cache_file" >&6;}
+  fi
+fi
+rm -f confcache
+
+test "x$prefix" = xNONE && prefix=$ac_default_prefix
+# Let make expand exec_prefix.
+test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'
+
+DEFS=-DHAVE_CONFIG_H
+
+ac_libobjs=
+ac_ltlibobjs=
+U=
+for ac_i in : $LIBOBJS; do test "x$ac_i" = x: && continue
+  # 1. Remove the extension, and $U if already installed.
+  ac_script='s/\$U\././;s/\.o$//;s/\.obj$//'
+  ac_i=`$as_echo "$ac_i" | sed "$ac_script"`
+  # 2. Prepend LIBOBJDIR.  When used with automake>=1.10 LIBOBJDIR
+  #    will be set to the directory where LIBOBJS objects are built.
+  as_fn_append ac_libobjs " \${LIBOBJDIR}$ac_i\$U.$ac_objext"
+  as_fn_append ac_ltlibobjs " \${LIBOBJDIR}$ac_i"'$U.lo'
+done
+LIBOBJS=$ac_libobjs
+
+LTLIBOBJS=$ac_ltlibobjs
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking that generated files are newer than configure" >&5
+$as_echo_n "checking that generated files are newer than configure... " >&6; }
+   if test -n "$am_sleep_pid"; then
+     # Hide warnings about reused PIDs.
+     wait $am_sleep_pid 2>/dev/null
+   fi
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: done" >&5
+$as_echo "done" >&6; }
+ if test -n "$EXEEXT"; then
+  am__EXEEXT_TRUE=
+  am__EXEEXT_FALSE='#'
+else
+  am__EXEEXT_TRUE='#'
+  am__EXEEXT_FALSE=
+fi
+
+if test -z "${MAINTAINER_MODE_TRUE}" && test -z "${MAINTAINER_MODE_FALSE}"; then
+  as_fn_error $? "conditional \"MAINTAINER_MODE\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${AMDEP_TRUE}" && test -z "${AMDEP_FALSE}"; then
+  as_fn_error $? "conditional \"AMDEP\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${am__fastdepCC_TRUE}" && test -z "${am__fastdepCC_FALSE}"; then
+  as_fn_error $? "conditional \"am__fastdepCC\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${am__fastdepCCAS_TRUE}" && test -z "${am__fastdepCCAS_FALSE}"; then
+  as_fn_error $? "conditional \"am__fastdepCCAS\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${HAVE_CLOCK_GETTIME_TRUE}" && test -z "${HAVE_CLOCK_GETTIME_FALSE}"; then
+  as_fn_error $? "conditional \"HAVE_CLOCK_GETTIME\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${HAVE_SOLARIS_LD_TRUE}" && test -z "${HAVE_SOLARIS_LD_FALSE}"; then
+  as_fn_error $? "conditional \"HAVE_SOLARIS_LD\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${HAVE_LD_VERSION_SCRIPT_TRUE}" && test -z "${HAVE_LD_VERSION_SCRIPT_FALSE}"; then
+  as_fn_error $? "conditional \"HAVE_LD_VERSION_SCRIPT\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${DO_PNG_PREFIX_TRUE}" && test -z "${DO_PNG_PREFIX_FALSE}"; then
+  as_fn_error $? "conditional \"DO_PNG_PREFIX\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${DO_INSTALL_LINKS_TRUE}" && test -z "${DO_INSTALL_LINKS_FALSE}"; then
+  as_fn_error $? "conditional \"DO_INSTALL_LINKS\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${DO_INSTALL_LIBPNG_PC_TRUE}" && test -z "${DO_INSTALL_LIBPNG_PC_FALSE}"; then
+  as_fn_error $? "conditional \"DO_INSTALL_LIBPNG_PC\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${DO_INSTALL_LIBPNG_CONFIG_TRUE}" && test -z "${DO_INSTALL_LIBPNG_CONFIG_FALSE}"; then
+  as_fn_error $? "conditional \"DO_INSTALL_LIBPNG_CONFIG\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_ARM_NEON_TRUE}" && test -z "${PNG_ARM_NEON_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_ARM_NEON\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_MIPS_MSA_TRUE}" && test -z "${PNG_MIPS_MSA_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_MIPS_MSA\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_INTEL_SSE_TRUE}" && test -z "${PNG_INTEL_SSE_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_INTEL_SSE\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_POWERPC_VSX_TRUE}" && test -z "${PNG_POWERPC_VSX_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_POWERPC_VSX\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+
+: "${CONFIG_STATUS=./config.status}"
+ac_write_fail=0
+ac_clean_files_save=$ac_clean_files
+ac_clean_files="$ac_clean_files $CONFIG_STATUS"
+{ $as_echo "$as_me:${as_lineno-$LINENO}: creating $CONFIG_STATUS" >&5
+$as_echo "$as_me: creating $CONFIG_STATUS" >&6;}
+as_write_fail=0
+cat >$CONFIG_STATUS <<_ASEOF || as_write_fail=1
+#! $SHELL
+# Generated by $as_me.
+# Run this file to recreate the current configuration.
+# Compiler output produced by configure, useful for debugging
+# configure, is in config.log if it exists.
+
+debug=false
+ac_cs_recheck=false
+ac_cs_silent=false
+
+SHELL=\${CONFIG_SHELL-$SHELL}
+export SHELL
+_ASEOF
+cat >>$CONFIG_STATUS <<\_ASEOF || as_write_fail=1
+## -------------------- ##
+## M4sh Initialization. ##
+## -------------------- ##
+
+# Be more Bourne compatible
+DUALCASE=1; export DUALCASE # for MKS sh
+if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else
+  case `(set -o) 2>/dev/null` in #(
+  *posix*) :
+    set -o posix ;; #(
+  *) :
+     ;;
+esac
+fi
+
+
+as_nl='
+'
+export as_nl
+# Printing a long string crashes Solaris 7 /usr/bin/printf.
+as_echo='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
+as_echo=$as_echo$as_echo$as_echo$as_echo$as_echo
+as_echo=$as_echo$as_echo$as_echo$as_echo$as_echo$as_echo
+# Prefer a ksh shell builtin over an external printf program on Solaris,
+# but without wasting forks for bash or zsh.
+if test -z "$BASH_VERSION$ZSH_VERSION" \
+    && (test "X`print -r -- $as_echo`" = "X$as_echo") 2>/dev/null; then
+  as_echo='print -r --'
+  as_echo_n='print -rn --'
+elif (test "X`printf %s $as_echo`" = "X$as_echo") 2>/dev/null; then
+  as_echo='printf %s\n'
+  as_echo_n='printf %s'
+else
+  if test "X`(/usr/ucb/echo -n -n $as_echo) 2>/dev/null`" = "X-n $as_echo"; then
+    as_echo_body='eval /usr/ucb/echo -n "$1$as_nl"'
+    as_echo_n='/usr/ucb/echo -n'
+  else
+    as_echo_body='eval expr "X$1" : "X\\(.*\\)"'
+    as_echo_n_body='eval
+      arg=$1;
+      case $arg in #(
+      *"$as_nl"*)
+	expr "X$arg" : "X\\(.*\\)$as_nl";
+	arg=`expr "X$arg" : ".*$as_nl\\(.*\\)"`;;
+      esac;
+      expr "X$arg" : "X\\(.*\\)" | tr -d "$as_nl"
+    '
+    export as_echo_n_body
+    as_echo_n='sh -c $as_echo_n_body as_echo'
+  fi
+  export as_echo_body
+  as_echo='sh -c $as_echo_body as_echo'
+fi
+
+# The user is always right.
+if test "${PATH_SEPARATOR+set}" != set; then
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
+    (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
+      PATH_SEPARATOR=';'
+  }
+fi
+
+
+# IFS
+# We need space, tab and new line, in precisely that order.  Quoting is
+# there to prevent editors from complaining about space-tab.
+# (If _AS_PATH_WALK were called with IFS unset, it would disable word
+# splitting by setting IFS to empty value.)
+IFS=" ""	$as_nl"
+
+# Find who we are.  Look in the path if we contain no directory separator.
+as_myself=
+case $0 in #((
+  *[\\/]* ) as_myself=$0 ;;
+  *) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    test -r "$as_dir/$0" && as_myself=$as_dir/$0 && break
+  done
+IFS=$as_save_IFS
+
+     ;;
+esac
+# We did not find ourselves, most probably we were run as `sh COMMAND'
+# in which case we are not to be found in the path.
+if test "x$as_myself" = x; then
+  as_myself=$0
+fi
+if test ! -f "$as_myself"; then
+  $as_echo "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
+  exit 1
+fi
+
+# Unset variables that we do not need and which cause bugs (e.g. in
+# pre-3.0 UWIN ksh).  But do not cause bugs in bash 2.01; the "|| exit 1"
+# suppresses any "Segmentation fault" message there.  '((' could
+# trigger a bug in pdksh 5.2.14.
+for as_var in BASH_ENV ENV MAIL MAILPATH
+do eval test x\${$as_var+set} = xset \
+  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
+done
+PS1='$ '
+PS2='> '
+PS4='+ '
+
+# NLS nuisances.
+LC_ALL=C
+export LC_ALL
+LANGUAGE=C
+export LANGUAGE
+
+# CDPATH.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+
+# as_fn_error STATUS ERROR [LINENO LOG_FD]
+# ----------------------------------------
+# Output "`basename $0`: error: ERROR" to stderr. If LINENO and LOG_FD are
+# provided, also output the error to LOG_FD, referencing LINENO. Then exit the
+# script with STATUS, using 1 if that was 0.
+as_fn_error ()
+{
+  as_status=$1; test $as_status -eq 0 && as_status=1
+  if test "$4"; then
+    as_lineno=${as_lineno-"$3"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+    $as_echo "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
+  fi
+  $as_echo "$as_me: error: $2" >&2
+  as_fn_exit $as_status
+} # as_fn_error
+
+
+# as_fn_set_status STATUS
+# -----------------------
+# Set $? to STATUS, without forking.
+as_fn_set_status ()
+{
+  return $1
+} # as_fn_set_status
+
+# as_fn_exit STATUS
+# -----------------
+# Exit the shell with STATUS, even in a "trap 0" or "set -e" context.
+as_fn_exit ()
+{
+  set +e
+  as_fn_set_status $1
+  exit $1
+} # as_fn_exit
+
+# as_fn_unset VAR
+# ---------------
+# Portably unset VAR.
+as_fn_unset ()
+{
+  { eval $1=; unset $1;}
+}
+as_unset=as_fn_unset
+# as_fn_append VAR VALUE
+# ----------------------
+# Append the text in VALUE to the end of the definition contained in VAR. Take
+# advantage of any shell optimizations that allow amortized linear growth over
+# repeated appends, instead of the typical quadratic growth present in naive
+# implementations.
+if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null; then :
+  eval 'as_fn_append ()
+  {
+    eval $1+=\$2
+  }'
+else
+  as_fn_append ()
+  {
+    eval $1=\$$1\$2
+  }
+fi # as_fn_append
+
+# as_fn_arith ARG...
+# ------------------
+# Perform arithmetic evaluation on the ARGs, and store the result in the
+# global $as_val. Take advantage of shells that can avoid forks. The arguments
+# must be portable across $(()) and expr.
+if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null; then :
+  eval 'as_fn_arith ()
+  {
+    as_val=$(( $* ))
+  }'
+else
+  as_fn_arith ()
+  {
+    as_val=`expr "$@" || test $? -eq 1`
+  }
+fi # as_fn_arith
+
+
+if expr a : '\(a\)' >/dev/null 2>&1 &&
+   test "X`expr 00001 : '.*\(...\)'`" = X001; then
+  as_expr=expr
+else
+  as_expr=false
+fi
+
+if (basename -- /) >/dev/null 2>&1 && test "X`basename -- / 2>&1`" = "X/"; then
+  as_basename=basename
+else
+  as_basename=false
+fi
+
+if (as_dir=`dirname -- /` && test "X$as_dir" = X/) >/dev/null 2>&1; then
+  as_dirname=dirname
+else
+  as_dirname=false
+fi
+
+as_me=`$as_basename -- "$0" ||
+$as_expr X/"$0" : '.*/\([^/][^/]*\)/*$' \| \
+	 X"$0" : 'X\(//\)$' \| \
+	 X"$0" : 'X\(/\)' \| . 2>/dev/null ||
+$as_echo X/"$0" |
+    sed '/^.*\/\([^/][^/]*\)\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+
+# Avoid depending upon Character Ranges.
+as_cr_letters='abcdefghijklmnopqrstuvwxyz'
+as_cr_LETTERS='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+as_cr_Letters=$as_cr_letters$as_cr_LETTERS
+as_cr_digits='0123456789'
+as_cr_alnum=$as_cr_Letters$as_cr_digits
+
+ECHO_C= ECHO_N= ECHO_T=
+case `echo -n x` in #(((((
+-n*)
+  case `echo 'xy\c'` in
+  *c*) ECHO_T='	';;	# ECHO_T is single tab character.
+  xy)  ECHO_C='\c';;
+  *)   echo `echo ksh88 bug on AIX 6.1` > /dev/null
+       ECHO_T='	';;
+  esac;;
+*)
+  ECHO_N='-n';;
+esac
+
+rm -f conf$$ conf$$.exe conf$$.file
+if test -d conf$$.dir; then
+  rm -f conf$$.dir/conf$$.file
+else
+  rm -f conf$$.dir
+  mkdir conf$$.dir 2>/dev/null
+fi
+if (echo >conf$$.file) 2>/dev/null; then
+  if ln -s conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s='ln -s'
+    # ... but there are two gotchas:
+    # 1) On MSYS, both `ln -s file dir' and `ln file dir' fail.
+    # 2) DJGPP < 2.04 has no symlinks; `ln -s' creates a wrapper executable.
+    # In both cases, we have to default to `cp -pR'.
+    ln -s conf$$.file conf$$.dir 2>/dev/null && test ! -f conf$$.exe ||
+      as_ln_s='cp -pR'
+  elif ln conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s=ln
+  else
+    as_ln_s='cp -pR'
+  fi
+else
+  as_ln_s='cp -pR'
+fi
+rm -f conf$$ conf$$.exe conf$$.dir/conf$$.file conf$$.file
+rmdir conf$$.dir 2>/dev/null
+
+
+# as_fn_mkdir_p
+# -------------
+# Create "$as_dir" as a directory, including parents if necessary.
+as_fn_mkdir_p ()
+{
+
+  case $as_dir in #(
+  -*) as_dir=./$as_dir;;
+  esac
+  test -d "$as_dir" || eval $as_mkdir_p || {
+    as_dirs=
+    while :; do
+      case $as_dir in #(
+      *\'*) as_qdir=`$as_echo "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
+      *) as_qdir=$as_dir;;
+      esac
+      as_dirs="'$as_qdir' $as_dirs"
+      as_dir=`$as_dirname -- "$as_dir" ||
+$as_expr X"$as_dir" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$as_dir" : 'X\(//\)[^/]' \| \
+	 X"$as_dir" : 'X\(//\)$' \| \
+	 X"$as_dir" : 'X\(/\)' \| . 2>/dev/null ||
+$as_echo X"$as_dir" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+      test -d "$as_dir" && break
+    done
+    test -z "$as_dirs" || eval "mkdir $as_dirs"
+  } || test -d "$as_dir" || as_fn_error $? "cannot create directory $as_dir"
+
+
+} # as_fn_mkdir_p
+if mkdir -p . 2>/dev/null; then
+  as_mkdir_p='mkdir -p "$as_dir"'
+else
+  test -d ./-p && rmdir ./-p
+  as_mkdir_p=false
+fi
+
+
+# as_fn_executable_p FILE
+# -----------------------
+# Test if FILE is an executable regular file.
+as_fn_executable_p ()
+{
+  test -f "$1" && test -x "$1"
+} # as_fn_executable_p
+as_test_x='test -x'
+as_executable_p=as_fn_executable_p
+
+# Sed expression to map a string onto a valid CPP name.
+as_tr_cpp="eval sed 'y%*$as_cr_letters%P$as_cr_LETTERS%;s%[^_$as_cr_alnum]%_%g'"
+
+# Sed expression to map a string onto a valid variable name.
+as_tr_sh="eval sed 'y%*+%pp%;s%[^_$as_cr_alnum]%_%g'"
+
+
+exec 6>&1
+## ----------------------------------- ##
+## Main body of $CONFIG_STATUS script. ##
+## ----------------------------------- ##
+_ASEOF
+test $as_write_fail = 0 && chmod +x $CONFIG_STATUS || ac_write_fail=1
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+# Save the log message, to keep $0 and so on meaningful, and to
+# report actual input values of CONFIG_FILES etc. instead of their
+# values after options handling.
+ac_log="
+This file was extended by libpng $as_me 1.6.37, which was
+generated by GNU Autoconf 2.69.  Invocation command line was
+
+  CONFIG_FILES    = $CONFIG_FILES
+  CONFIG_HEADERS  = $CONFIG_HEADERS
+  CONFIG_LINKS    = $CONFIG_LINKS
+  CONFIG_COMMANDS = $CONFIG_COMMANDS
+  $ $0 $@
+
+on `(hostname || uname -n) 2>/dev/null | sed 1q`
+"
+
+_ACEOF
+
+case $ac_config_files in *"
+"*) set x $ac_config_files; shift; ac_config_files=$*;;
+esac
+
+case $ac_config_headers in *"
+"*) set x $ac_config_headers; shift; ac_config_headers=$*;;
+esac
+
+
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+# Files that config.status was made for.
+config_files="$ac_config_files"
+config_headers="$ac_config_headers"
+config_commands="$ac_config_commands"
+
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+ac_cs_usage="\
+\`$as_me' instantiates files and other configuration actions
+from templates according to the current configuration.  Unless the files
+and actions are specified as TAGs, all are instantiated by default.
+
+Usage: $0 [OPTION]... [TAG]...
+
+  -h, --help       print this help, then exit
+  -V, --version    print version number and configuration settings, then exit
+      --config     print configuration, then exit
+  -q, --quiet, --silent
+                   do not print progress messages
+  -d, --debug      don't remove temporary files
+      --recheck    update $as_me by reconfiguring in the same conditions
+      --file=FILE[:TEMPLATE]
+                   instantiate the configuration file FILE
+      --header=FILE[:TEMPLATE]
+                   instantiate the configuration header FILE
+
+Configuration files:
+$config_files
+
+Configuration headers:
+$config_headers
+
+Configuration commands:
+$config_commands
+
+Report bugs to <png-mng-implement@lists.sourceforge.net>."
+
+_ACEOF
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
+ac_cs_version="\\
+libpng config.status 1.6.37
+configured by $0, generated by GNU Autoconf 2.69,
+  with options \\"\$ac_cs_config\\"
+
+Copyright (C) 2012 Free Software Foundation, Inc.
+This config.status script is free software; the Free Software Foundation
+gives unlimited permission to copy, distribute and modify it."
+
+ac_pwd='$ac_pwd'
+srcdir='$srcdir'
+INSTALL='$INSTALL'
+MKDIR_P='$MKDIR_P'
+AWK='$AWK'
+test -n "\$AWK" || AWK=awk
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+# The default lists apply if the user does not specify any file.
+ac_need_defaults=:
+while test $# != 0
+do
+  case $1 in
+  --*=?*)
+    ac_option=`expr "X$1" : 'X\([^=]*\)='`
+    ac_optarg=`expr "X$1" : 'X[^=]*=\(.*\)'`
+    ac_shift=:
+    ;;
+  --*=)
+    ac_option=`expr "X$1" : 'X\([^=]*\)='`
+    ac_optarg=
+    ac_shift=:
+    ;;
+  *)
+    ac_option=$1
+    ac_optarg=$2
+    ac_shift=shift
+    ;;
+  esac
+
+  case $ac_option in
+  # Handling of the options.
+  -recheck | --recheck | --rechec | --reche | --rech | --rec | --re | --r)
+    ac_cs_recheck=: ;;
+  --version | --versio | --versi | --vers | --ver | --ve | --v | -V )
+    $as_echo "$ac_cs_version"; exit ;;
+  --config | --confi | --conf | --con | --co | --c )
+    $as_echo "$ac_cs_config"; exit ;;
+  --debug | --debu | --deb | --de | --d | -d )
+    debug=: ;;
+  --file | --fil | --fi | --f )
+    $ac_shift
+    case $ac_optarg in
+    *\'*) ac_optarg=`$as_echo "$ac_optarg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    '') as_fn_error $? "missing file argument" ;;
+    esac
+    as_fn_append CONFIG_FILES " '$ac_optarg'"
+    ac_need_defaults=false;;
+  --header | --heade | --head | --hea )
+    $ac_shift
+    case $ac_optarg in
+    *\'*) ac_optarg=`$as_echo "$ac_optarg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    esac
+    as_fn_append CONFIG_HEADERS " '$ac_optarg'"
+    ac_need_defaults=false;;
+  --he | --h)
+    # Conflict between --help and --header
+    as_fn_error $? "ambiguous option: \`$1'
+Try \`$0 --help' for more information.";;
+  --help | --hel | -h )
+    $as_echo "$ac_cs_usage"; exit ;;
+  -q | -quiet | --quiet | --quie | --qui | --qu | --q \
+  | -silent | --silent | --silen | --sile | --sil | --si | --s)
+    ac_cs_silent=: ;;
+
+  # This is an error.
+  -*) as_fn_error $? "unrecognized option: \`$1'
+Try \`$0 --help' for more information." ;;
+
+  *) as_fn_append ac_config_targets " $1"
+     ac_need_defaults=false ;;
+
+  esac
+  shift
+done
+
+ac_configure_extra_args=
+
+if $ac_cs_silent; then
+  exec 6>/dev/null
+  ac_configure_extra_args="$ac_configure_extra_args --silent"
+fi
+
+_ACEOF
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+if \$ac_cs_recheck; then
+  set X $SHELL '$0' $ac_configure_args \$ac_configure_extra_args --no-create --no-recursion
+  shift
+  \$as_echo "running CONFIG_SHELL=$SHELL \$*" >&6
+  CONFIG_SHELL='$SHELL'
+  export CONFIG_SHELL
+  exec "\$@"
+fi
+
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+exec 5>>config.log
+{
+  echo
+  sed 'h;s/./-/g;s/^.../## /;s/...$/ ##/;p;x;p;x' <<_ASBOX
+## Running $as_me. ##
+_ASBOX
+  $as_echo "$ac_log"
+} >&5
+
+_ACEOF
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+#
+# INIT-COMMANDS
+#
+AMDEP_TRUE="$AMDEP_TRUE" MAKE="${MAKE-make}"
+
+
+# The HP-UX ksh and POSIX shell print the target directory to stdout
+# if CDPATH is set.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+sed_quote_subst='$sed_quote_subst'
+double_quote_subst='$double_quote_subst'
+delay_variable_subst='$delay_variable_subst'
+SED='`$ECHO "$SED" | $SED "$delay_single_quote_subst"`'
+Xsed='`$ECHO "$Xsed" | $SED "$delay_single_quote_subst"`'
+GREP='`$ECHO "$GREP" | $SED "$delay_single_quote_subst"`'
+EGREP='`$ECHO "$EGREP" | $SED "$delay_single_quote_subst"`'
+FGREP='`$ECHO "$FGREP" | $SED "$delay_single_quote_subst"`'
+SHELL='`$ECHO "$SHELL" | $SED "$delay_single_quote_subst"`'
+ECHO='`$ECHO "$ECHO" | $SED "$delay_single_quote_subst"`'
+LD='`$ECHO "$LD" | $SED "$delay_single_quote_subst"`'
+macro_version='`$ECHO "$macro_version" | $SED "$delay_single_quote_subst"`'
+macro_revision='`$ECHO "$macro_revision" | $SED "$delay_single_quote_subst"`'
+AS='`$ECHO "$AS" | $SED "$delay_single_quote_subst"`'
+DLLTOOL='`$ECHO "$DLLTOOL" | $SED "$delay_single_quote_subst"`'
+OBJDUMP='`$ECHO "$OBJDUMP" | $SED "$delay_single_quote_subst"`'
+enable_shared='`$ECHO "$enable_shared" | $SED "$delay_single_quote_subst"`'
+enable_static='`$ECHO "$enable_static" | $SED "$delay_single_quote_subst"`'
+pic_mode='`$ECHO "$pic_mode" | $SED "$delay_single_quote_subst"`'
+enable_fast_install='`$ECHO "$enable_fast_install" | $SED "$delay_single_quote_subst"`'
+shared_archive_member_spec='`$ECHO "$shared_archive_member_spec" | $SED "$delay_single_quote_subst"`'
+PATH_SEPARATOR='`$ECHO "$PATH_SEPARATOR" | $SED "$delay_single_quote_subst"`'
+host_alias='`$ECHO "$host_alias" | $SED "$delay_single_quote_subst"`'
+host='`$ECHO "$host" | $SED "$delay_single_quote_subst"`'
+host_os='`$ECHO "$host_os" | $SED "$delay_single_quote_subst"`'
+build_alias='`$ECHO "$build_alias" | $SED "$delay_single_quote_subst"`'
+build='`$ECHO "$build" | $SED "$delay_single_quote_subst"`'
+build_os='`$ECHO "$build_os" | $SED "$delay_single_quote_subst"`'
+NM='`$ECHO "$NM" | $SED "$delay_single_quote_subst"`'
+LN_S='`$ECHO "$LN_S" | $SED "$delay_single_quote_subst"`'
+max_cmd_len='`$ECHO "$max_cmd_len" | $SED "$delay_single_quote_subst"`'
+ac_objext='`$ECHO "$ac_objext" | $SED "$delay_single_quote_subst"`'
+exeext='`$ECHO "$exeext" | $SED "$delay_single_quote_subst"`'
+lt_unset='`$ECHO "$lt_unset" | $SED "$delay_single_quote_subst"`'
+lt_SP2NL='`$ECHO "$lt_SP2NL" | $SED "$delay_single_quote_subst"`'
+lt_NL2SP='`$ECHO "$lt_NL2SP" | $SED "$delay_single_quote_subst"`'
+lt_cv_to_host_file_cmd='`$ECHO "$lt_cv_to_host_file_cmd" | $SED "$delay_single_quote_subst"`'
+lt_cv_to_tool_file_cmd='`$ECHO "$lt_cv_to_tool_file_cmd" | $SED "$delay_single_quote_subst"`'
+reload_flag='`$ECHO "$reload_flag" | $SED "$delay_single_quote_subst"`'
+reload_cmds='`$ECHO "$reload_cmds" | $SED "$delay_single_quote_subst"`'
+deplibs_check_method='`$ECHO "$deplibs_check_method" | $SED "$delay_single_quote_subst"`'
+file_magic_cmd='`$ECHO "$file_magic_cmd" | $SED "$delay_single_quote_subst"`'
+file_magic_glob='`$ECHO "$file_magic_glob" | $SED "$delay_single_quote_subst"`'
+want_nocaseglob='`$ECHO "$want_nocaseglob" | $SED "$delay_single_quote_subst"`'
+sharedlib_from_linklib_cmd='`$ECHO "$sharedlib_from_linklib_cmd" | $SED "$delay_single_quote_subst"`'
+AR='`$ECHO "$AR" | $SED "$delay_single_quote_subst"`'
+AR_FLAGS='`$ECHO "$AR_FLAGS" | $SED "$delay_single_quote_subst"`'
+archiver_list_spec='`$ECHO "$archiver_list_spec" | $SED "$delay_single_quote_subst"`'
+STRIP='`$ECHO "$STRIP" | $SED "$delay_single_quote_subst"`'
+RANLIB='`$ECHO "$RANLIB" | $SED "$delay_single_quote_subst"`'
+old_postinstall_cmds='`$ECHO "$old_postinstall_cmds" | $SED "$delay_single_quote_subst"`'
+old_postuninstall_cmds='`$ECHO "$old_postuninstall_cmds" | $SED "$delay_single_quote_subst"`'
+old_archive_cmds='`$ECHO "$old_archive_cmds" | $SED "$delay_single_quote_subst"`'
+lock_old_archive_extraction='`$ECHO "$lock_old_archive_extraction" | $SED "$delay_single_quote_subst"`'
+CC='`$ECHO "$CC" | $SED "$delay_single_quote_subst"`'
+CFLAGS='`$ECHO "$CFLAGS" | $SED "$delay_single_quote_subst"`'
+compiler='`$ECHO "$compiler" | $SED "$delay_single_quote_subst"`'
+GCC='`$ECHO "$GCC" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_pipe='`$ECHO "$lt_cv_sys_global_symbol_pipe" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_to_cdecl='`$ECHO "$lt_cv_sys_global_symbol_to_cdecl" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_to_import='`$ECHO "$lt_cv_sys_global_symbol_to_import" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_to_c_name_address='`$ECHO "$lt_cv_sys_global_symbol_to_c_name_address" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_to_c_name_address_lib_prefix='`$ECHO "$lt_cv_sys_global_symbol_to_c_name_address_lib_prefix" | $SED "$delay_single_quote_subst"`'
+lt_cv_nm_interface='`$ECHO "$lt_cv_nm_interface" | $SED "$delay_single_quote_subst"`'
+nm_file_list_spec='`$ECHO "$nm_file_list_spec" | $SED "$delay_single_quote_subst"`'
+lt_sysroot='`$ECHO "$lt_sysroot" | $SED "$delay_single_quote_subst"`'
+lt_cv_truncate_bin='`$ECHO "$lt_cv_truncate_bin" | $SED "$delay_single_quote_subst"`'
+objdir='`$ECHO "$objdir" | $SED "$delay_single_quote_subst"`'
+MAGIC_CMD='`$ECHO "$MAGIC_CMD" | $SED "$delay_single_quote_subst"`'
+lt_prog_compiler_no_builtin_flag='`$ECHO "$lt_prog_compiler_no_builtin_flag" | $SED "$delay_single_quote_subst"`'
+lt_prog_compiler_pic='`$ECHO "$lt_prog_compiler_pic" | $SED "$delay_single_quote_subst"`'
+lt_prog_compiler_wl='`$ECHO "$lt_prog_compiler_wl" | $SED "$delay_single_quote_subst"`'
+lt_prog_compiler_static='`$ECHO "$lt_prog_compiler_static" | $SED "$delay_single_quote_subst"`'
+lt_cv_prog_compiler_c_o='`$ECHO "$lt_cv_prog_compiler_c_o" | $SED "$delay_single_quote_subst"`'
+need_locks='`$ECHO "$need_locks" | $SED "$delay_single_quote_subst"`'
+MANIFEST_TOOL='`$ECHO "$MANIFEST_TOOL" | $SED "$delay_single_quote_subst"`'
+DSYMUTIL='`$ECHO "$DSYMUTIL" | $SED "$delay_single_quote_subst"`'
+NMEDIT='`$ECHO "$NMEDIT" | $SED "$delay_single_quote_subst"`'
+LIPO='`$ECHO "$LIPO" | $SED "$delay_single_quote_subst"`'
+OTOOL='`$ECHO "$OTOOL" | $SED "$delay_single_quote_subst"`'
+OTOOL64='`$ECHO "$OTOOL64" | $SED "$delay_single_quote_subst"`'
+libext='`$ECHO "$libext" | $SED "$delay_single_quote_subst"`'
+shrext_cmds='`$ECHO "$shrext_cmds" | $SED "$delay_single_quote_subst"`'
+extract_expsyms_cmds='`$ECHO "$extract_expsyms_cmds" | $SED "$delay_single_quote_subst"`'
+archive_cmds_need_lc='`$ECHO "$archive_cmds_need_lc" | $SED "$delay_single_quote_subst"`'
+enable_shared_with_static_runtimes='`$ECHO "$enable_shared_with_static_runtimes" | $SED "$delay_single_quote_subst"`'
+export_dynamic_flag_spec='`$ECHO "$export_dynamic_flag_spec" | $SED "$delay_single_quote_subst"`'
+whole_archive_flag_spec='`$ECHO "$whole_archive_flag_spec" | $SED "$delay_single_quote_subst"`'
+compiler_needs_object='`$ECHO "$compiler_needs_object" | $SED "$delay_single_quote_subst"`'
+old_archive_from_new_cmds='`$ECHO "$old_archive_from_new_cmds" | $SED "$delay_single_quote_subst"`'
+old_archive_from_expsyms_cmds='`$ECHO "$old_archive_from_expsyms_cmds" | $SED "$delay_single_quote_subst"`'
+archive_cmds='`$ECHO "$archive_cmds" | $SED "$delay_single_quote_subst"`'
+archive_expsym_cmds='`$ECHO "$archive_expsym_cmds" | $SED "$delay_single_quote_subst"`'
+module_cmds='`$ECHO "$module_cmds" | $SED "$delay_single_quote_subst"`'
+module_expsym_cmds='`$ECHO "$module_expsym_cmds" | $SED "$delay_single_quote_subst"`'
+with_gnu_ld='`$ECHO "$with_gnu_ld" | $SED "$delay_single_quote_subst"`'
+allow_undefined_flag='`$ECHO "$allow_undefined_flag" | $SED "$delay_single_quote_subst"`'
+no_undefined_flag='`$ECHO "$no_undefined_flag" | $SED "$delay_single_quote_subst"`'
+hardcode_libdir_flag_spec='`$ECHO "$hardcode_libdir_flag_spec" | $SED "$delay_single_quote_subst"`'
+hardcode_libdir_separator='`$ECHO "$hardcode_libdir_separator" | $SED "$delay_single_quote_subst"`'
+hardcode_direct='`$ECHO "$hardcode_direct" | $SED "$delay_single_quote_subst"`'
+hardcode_direct_absolute='`$ECHO "$hardcode_direct_absolute" | $SED "$delay_single_quote_subst"`'
+hardcode_minus_L='`$ECHO "$hardcode_minus_L" | $SED "$delay_single_quote_subst"`'
+hardcode_shlibpath_var='`$ECHO "$hardcode_shlibpath_var" | $SED "$delay_single_quote_subst"`'
+hardcode_automatic='`$ECHO "$hardcode_automatic" | $SED "$delay_single_quote_subst"`'
+inherit_rpath='`$ECHO "$inherit_rpath" | $SED "$delay_single_quote_subst"`'
+link_all_deplibs='`$ECHO "$link_all_deplibs" | $SED "$delay_single_quote_subst"`'
+always_export_symbols='`$ECHO "$always_export_symbols" | $SED "$delay_single_quote_subst"`'
+export_symbols_cmds='`$ECHO "$export_symbols_cmds" | $SED "$delay_single_quote_subst"`'
+exclude_expsyms='`$ECHO "$exclude_expsyms" | $SED "$delay_single_quote_subst"`'
+include_expsyms='`$ECHO "$include_expsyms" | $SED "$delay_single_quote_subst"`'
+prelink_cmds='`$ECHO "$prelink_cmds" | $SED "$delay_single_quote_subst"`'
+postlink_cmds='`$ECHO "$postlink_cmds" | $SED "$delay_single_quote_subst"`'
+file_list_spec='`$ECHO "$file_list_spec" | $SED "$delay_single_quote_subst"`'
+variables_saved_for_relink='`$ECHO "$variables_saved_for_relink" | $SED "$delay_single_quote_subst"`'
+need_lib_prefix='`$ECHO "$need_lib_prefix" | $SED "$delay_single_quote_subst"`'
+need_version='`$ECHO "$need_version" | $SED "$delay_single_quote_subst"`'
+version_type='`$ECHO "$version_type" | $SED "$delay_single_quote_subst"`'
+runpath_var='`$ECHO "$runpath_var" | $SED "$delay_single_quote_subst"`'
+shlibpath_var='`$ECHO "$shlibpath_var" | $SED "$delay_single_quote_subst"`'
+shlibpath_overrides_runpath='`$ECHO "$shlibpath_overrides_runpath" | $SED "$delay_single_quote_subst"`'
+libname_spec='`$ECHO "$libname_spec" | $SED "$delay_single_quote_subst"`'
+library_names_spec='`$ECHO "$library_names_spec" | $SED "$delay_single_quote_subst"`'
+soname_spec='`$ECHO "$soname_spec" | $SED "$delay_single_quote_subst"`'
+install_override_mode='`$ECHO "$install_override_mode" | $SED "$delay_single_quote_subst"`'
+postinstall_cmds='`$ECHO "$postinstall_cmds" | $SED "$delay_single_quote_subst"`'
+postuninstall_cmds='`$ECHO "$postuninstall_cmds" | $SED "$delay_single_quote_subst"`'
+finish_cmds='`$ECHO "$finish_cmds" | $SED "$delay_single_quote_subst"`'
+finish_eval='`$ECHO "$finish_eval" | $SED "$delay_single_quote_subst"`'
+hardcode_into_libs='`$ECHO "$hardcode_into_libs" | $SED "$delay_single_quote_subst"`'
+sys_lib_search_path_spec='`$ECHO "$sys_lib_search_path_spec" | $SED "$delay_single_quote_subst"`'
+configure_time_dlsearch_path='`$ECHO "$configure_time_dlsearch_path" | $SED "$delay_single_quote_subst"`'
+configure_time_lt_sys_library_path='`$ECHO "$configure_time_lt_sys_library_path" | $SED "$delay_single_quote_subst"`'
+hardcode_action='`$ECHO "$hardcode_action" | $SED "$delay_single_quote_subst"`'
+enable_dlopen='`$ECHO "$enable_dlopen" | $SED "$delay_single_quote_subst"`'
+enable_dlopen_self='`$ECHO "$enable_dlopen_self" | $SED "$delay_single_quote_subst"`'
+enable_dlopen_self_static='`$ECHO "$enable_dlopen_self_static" | $SED "$delay_single_quote_subst"`'
+old_striplib='`$ECHO "$old_striplib" | $SED "$delay_single_quote_subst"`'
+striplib='`$ECHO "$striplib" | $SED "$delay_single_quote_subst"`'
+
+LTCC='$LTCC'
+LTCFLAGS='$LTCFLAGS'
+compiler='$compiler_DEFAULT'
+
+# A function that is used when there is no print builtin or printf.
+func_fallback_echo ()
+{
+  eval 'cat <<_LTECHO_EOF
+\$1
+_LTECHO_EOF'
+}
+
+# Quote evaled strings.
+for var in SED \
+GREP \
+EGREP \
+FGREP \
+SHELL \
+ECHO \
+LD \
+AS \
+DLLTOOL \
+OBJDUMP \
+PATH_SEPARATOR \
+NM \
+LN_S \
+lt_SP2NL \
+lt_NL2SP \
+reload_flag \
+deplibs_check_method \
+file_magic_cmd \
+file_magic_glob \
+want_nocaseglob \
+sharedlib_from_linklib_cmd \
+AR \
+AR_FLAGS \
+archiver_list_spec \
+STRIP \
+RANLIB \
+CC \
+CFLAGS \
+compiler \
+lt_cv_sys_global_symbol_pipe \
+lt_cv_sys_global_symbol_to_cdecl \
+lt_cv_sys_global_symbol_to_import \
+lt_cv_sys_global_symbol_to_c_name_address \
+lt_cv_sys_global_symbol_to_c_name_address_lib_prefix \
+lt_cv_nm_interface \
+nm_file_list_spec \
+lt_cv_truncate_bin \
+lt_prog_compiler_no_builtin_flag \
+lt_prog_compiler_pic \
+lt_prog_compiler_wl \
+lt_prog_compiler_static \
+lt_cv_prog_compiler_c_o \
+need_locks \
+MANIFEST_TOOL \
+DSYMUTIL \
+NMEDIT \
+LIPO \
+OTOOL \
+OTOOL64 \
+shrext_cmds \
+export_dynamic_flag_spec \
+whole_archive_flag_spec \
+compiler_needs_object \
+with_gnu_ld \
+allow_undefined_flag \
+no_undefined_flag \
+hardcode_libdir_flag_spec \
+hardcode_libdir_separator \
+exclude_expsyms \
+include_expsyms \
+file_list_spec \
+variables_saved_for_relink \
+libname_spec \
+library_names_spec \
+soname_spec \
+install_override_mode \
+finish_eval \
+old_striplib \
+striplib; do
+    case \`eval \\\\\$ECHO \\\\""\\\\\$\$var"\\\\"\` in
+    *[\\\\\\\`\\"\\\$]*)
+      eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"\\\$\$var\\" | \\\$SED \\"\\\$sed_quote_subst\\"\\\`\\\\\\"" ## exclude from sc_prohibit_nested_quotes
+      ;;
+    *)
+      eval "lt_\$var=\\\\\\"\\\$\$var\\\\\\""
+      ;;
+    esac
+done
+
+# Double-quote double-evaled strings.
+for var in reload_cmds \
+old_postinstall_cmds \
+old_postuninstall_cmds \
+old_archive_cmds \
+extract_expsyms_cmds \
+old_archive_from_new_cmds \
+old_archive_from_expsyms_cmds \
+archive_cmds \
+archive_expsym_cmds \
+module_cmds \
+module_expsym_cmds \
+export_symbols_cmds \
+prelink_cmds \
+postlink_cmds \
+postinstall_cmds \
+postuninstall_cmds \
+finish_cmds \
+sys_lib_search_path_spec \
+configure_time_dlsearch_path \
+configure_time_lt_sys_library_path; do
+    case \`eval \\\\\$ECHO \\\\""\\\\\$\$var"\\\\"\` in
+    *[\\\\\\\`\\"\\\$]*)
+      eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"\\\$\$var\\" | \\\$SED -e \\"\\\$double_quote_subst\\" -e \\"\\\$sed_quote_subst\\" -e \\"\\\$delay_variable_subst\\"\\\`\\\\\\"" ## exclude from sc_prohibit_nested_quotes
+      ;;
+    *)
+      eval "lt_\$var=\\\\\\"\\\$\$var\\\\\\""
+      ;;
+    esac
+done
+
+ac_aux_dir='$ac_aux_dir'
+
+# See if we are running on zsh, and set the options that allow our
+# commands through without removal of \ escapes INIT.
+if test -n "\${ZSH_VERSION+set}"; then
+   setopt NO_GLOB_SUBST
+fi
+
+
+    PACKAGE='$PACKAGE'
+    VERSION='$VERSION'
+    RM='$RM'
+    ofile='$ofile'
+
+
+
+
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+
+# Handling of arguments.
+for ac_config_target in $ac_config_targets
+do
+  case $ac_config_target in
+    "config.h") CONFIG_HEADERS="$CONFIG_HEADERS config.h" ;;
+    "depfiles") CONFIG_COMMANDS="$CONFIG_COMMANDS depfiles" ;;
+    "libtool") CONFIG_COMMANDS="$CONFIG_COMMANDS libtool" ;;
+    "Makefile") CONFIG_FILES="$CONFIG_FILES Makefile" ;;
+    "libpng.pc") CONFIG_FILES="$CONFIG_FILES libpng.pc:libpng.pc.in" ;;
+    "libpng-config") CONFIG_FILES="$CONFIG_FILES libpng-config:libpng-config.in" ;;
+
+  *) as_fn_error $? "invalid argument: \`$ac_config_target'" "$LINENO" 5;;
+  esac
+done
+
+
+# If the user did not use the arguments to specify the items to instantiate,
+# then the envvar interface is used.  Set only those that are not.
+# We use the long form for the default assignment because of an extremely
+# bizarre bug on SunOS 4.1.3.
+if $ac_need_defaults; then
+  test "${CONFIG_FILES+set}" = set || CONFIG_FILES=$config_files
+  test "${CONFIG_HEADERS+set}" = set || CONFIG_HEADERS=$config_headers
+  test "${CONFIG_COMMANDS+set}" = set || CONFIG_COMMANDS=$config_commands
+fi
+
+# Have a temporary directory for convenience.  Make it in the build tree
+# simply because there is no reason against having it here, and in addition,
+# creating and moving files from /tmp can sometimes cause problems.
+# Hook for its removal unless debugging.
+# Note that there is a small window in which the directory will not be cleaned:
+# after its creation but before its name has been assigned to `$tmp'.
+$debug ||
+{
+  tmp= ac_tmp=
+  trap 'exit_status=$?
+  : "${ac_tmp:=$tmp}"
+  { test ! -d "$ac_tmp" || rm -fr "$ac_tmp"; } && exit $exit_status
+' 0
+  trap 'as_fn_exit 1' 1 2 13 15
+}
+# Create a (secure) tmp directory for tmp files.
+
+{
+  tmp=`(umask 077 && mktemp -d "./confXXXXXX") 2>/dev/null` &&
+  test -d "$tmp"
+}  ||
+{
+  tmp=./conf$$-$RANDOM
+  (umask 077 && mkdir "$tmp")
+} || as_fn_error $? "cannot create a temporary directory in ." "$LINENO" 5
+ac_tmp=$tmp
+
+# Set up the scripts for CONFIG_FILES section.
+# No need to generate them if there are no CONFIG_FILES.
+# This happens for instance with `./config.status config.h'.
+if test -n "$CONFIG_FILES"; then
+
+
+ac_cr=`echo X | tr X '\015'`
+# On cygwin, bash can eat \r inside `` if the user requested igncr.
+# But we know of no other shell where ac_cr would be empty at this
+# point, so we can use a bashism as a fallback.
+if test "x$ac_cr" = x; then
+  eval ac_cr=\$\'\\r\'
+fi
+ac_cs_awk_cr=`$AWK 'BEGIN { print "a\rb" }' </dev/null 2>/dev/null`
+if test "$ac_cs_awk_cr" = "a${ac_cr}b"; then
+  ac_cs_awk_cr='\\r'
+else
+  ac_cs_awk_cr=$ac_cr
+fi
+
+echo 'BEGIN {' >"$ac_tmp/subs1.awk" &&
+_ACEOF
+
+
+{
+  echo "cat >conf$$subs.awk <<_ACEOF" &&
+  echo "$ac_subst_vars" | sed 's/.*/&!$&$ac_delim/' &&
+  echo "_ACEOF"
+} >conf$$subs.sh ||
+  as_fn_error $? "could not make $CONFIG_STATUS" "$LINENO" 5
+ac_delim_num=`echo "$ac_subst_vars" | grep -c '^'`
+ac_delim='%!_!# '
+for ac_last_try in false false false false false :; do
+  . ./conf$$subs.sh ||
+    as_fn_error $? "could not make $CONFIG_STATUS" "$LINENO" 5
+
+  ac_delim_n=`sed -n "s/.*$ac_delim\$/X/p" conf$$subs.awk | grep -c X`
+  if test $ac_delim_n = $ac_delim_num; then
+    break
+  elif $ac_last_try; then
+    as_fn_error $? "could not make $CONFIG_STATUS" "$LINENO" 5
+  else
+    ac_delim="$ac_delim!$ac_delim _$ac_delim!! "
+  fi
+done
+rm -f conf$$subs.sh
+
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+cat >>"\$ac_tmp/subs1.awk" <<\\_ACAWK &&
+_ACEOF
+sed -n '
+h
+s/^/S["/; s/!.*/"]=/
+p
+g
+s/^[^!]*!//
+:repl
+t repl
+s/'"$ac_delim"'$//
+t delim
+:nl
+h
+s/\(.\{148\}\)..*/\1/
+t more1
+s/["\\]/\\&/g; s/^/"/; s/$/\\n"\\/
+p
+n
+b repl
+:more1
+s/["\\]/\\&/g; s/^/"/; s/$/"\\/
+p
+g
+s/.\{148\}//
+t nl
+:delim
+h
+s/\(.\{148\}\)..*/\1/
+t more2
+s/["\\]/\\&/g; s/^/"/; s/$/"/
+p
+b
+:more2
+s/["\\]/\\&/g; s/^/"/; s/$/"\\/
+p
+g
+s/.\{148\}//
+t delim
+' <conf$$subs.awk | sed '
+/^[^""]/{
+  N
+  s/\n//
+}
+' >>$CONFIG_STATUS || ac_write_fail=1
+rm -f conf$$subs.awk
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+_ACAWK
+cat >>"\$ac_tmp/subs1.awk" <<_ACAWK &&
+  for (key in S) S_is_set[key] = 1
+  FS = ""
+
+}
+{
+  line = $ 0
+  nfields = split(line, field, "@")
+  substed = 0
+  len = length(field[1])
+  for (i = 2; i < nfields; i++) {
+    key = field[i]
+    keylen = length(key)
+    if (S_is_set[key]) {
+      value = S[key]
+      line = substr(line, 1, len) "" value "" substr(line, len + keylen + 3)
+      len += length(value) + length(field[++i])
+      substed = 1
+    } else
+      len += 1 + keylen
+  }
+
+  print line
+}
+
+_ACAWK
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+if sed "s/$ac_cr//" < /dev/null > /dev/null 2>&1; then
+  sed "s/$ac_cr\$//; s/$ac_cr/$ac_cs_awk_cr/g"
+else
+  cat
+fi < "$ac_tmp/subs1.awk" > "$ac_tmp/subs.awk" \
+  || as_fn_error $? "could not setup config files machinery" "$LINENO" 5
+_ACEOF
+
+# VPATH may cause trouble with some makes, so we remove sole $(srcdir),
+# ${srcdir} and @srcdir@ entries from VPATH if srcdir is ".", strip leading and
+# trailing colons and then remove the whole line if VPATH becomes empty
+# (actually we leave an empty line to preserve line numbers).
+if test "x$srcdir" = x.; then
+  ac_vpsub='/^[	 ]*VPATH[	 ]*=[	 ]*/{
+h
+s///
+s/^/:/
+s/[	 ]*$/:/
+s/:\$(srcdir):/:/g
+s/:\${srcdir}:/:/g
+s/:@srcdir@:/:/g
+s/^:*//
+s/:*$//
+x
+s/\(=[	 ]*\).*/\1/
+G
+s/\n//
+s/^[^=]*=[	 ]*$//
+}'
+fi
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+fi # test -n "$CONFIG_FILES"
+
+# Set up the scripts for CONFIG_HEADERS section.
+# No need to generate them if there are no CONFIG_HEADERS.
+# This happens for instance with `./config.status Makefile'.
+if test -n "$CONFIG_HEADERS"; then
+cat >"$ac_tmp/defines.awk" <<\_ACAWK ||
+BEGIN {
+_ACEOF
+
+# Transform confdefs.h into an awk script `defines.awk', embedded as
+# here-document in config.status, that substitutes the proper values into
+# config.h.in to produce config.h.
+
+# Create a delimiter string that does not exist in confdefs.h, to ease
+# handling of long lines.
+ac_delim='%!_!# '
+for ac_last_try in false false :; do
+  ac_tt=`sed -n "/$ac_delim/p" confdefs.h`
+  if test -z "$ac_tt"; then
+    break
+  elif $ac_last_try; then
+    as_fn_error $? "could not make $CONFIG_HEADERS" "$LINENO" 5
+  else
+    ac_delim="$ac_delim!$ac_delim _$ac_delim!! "
+  fi
+done
+
+# For the awk script, D is an array of macro values keyed by name,
+# likewise P contains macro parameters if any.  Preserve backslash
+# newline sequences.
+
+ac_word_re=[_$as_cr_Letters][_$as_cr_alnum]*
+sed -n '
+s/.\{148\}/&'"$ac_delim"'/g
+t rset
+:rset
+s/^[	 ]*#[	 ]*define[	 ][	 ]*/ /
+t def
+d
+:def
+s/\\$//
+t bsnl
+s/["\\]/\\&/g
+s/^ \('"$ac_word_re"'\)\(([^()]*)\)[	 ]*\(.*\)/P["\1"]="\2"\
+D["\1"]=" \3"/p
+s/^ \('"$ac_word_re"'\)[	 ]*\(.*\)/D["\1"]=" \2"/p
+d
+:bsnl
+s/["\\]/\\&/g
+s/^ \('"$ac_word_re"'\)\(([^()]*)\)[	 ]*\(.*\)/P["\1"]="\2"\
+D["\1"]=" \3\\\\\\n"\\/p
+t cont
+s/^ \('"$ac_word_re"'\)[	 ]*\(.*\)/D["\1"]=" \2\\\\\\n"\\/p
+t cont
+d
+:cont
+n
+s/.\{148\}/&'"$ac_delim"'/g
+t clear
+:clear
+s/\\$//
+t bsnlc
+s/["\\]/\\&/g; s/^/"/; s/$/"/p
+d
+:bsnlc
+s/["\\]/\\&/g; s/^/"/; s/$/\\\\\\n"\\/p
+b cont
+' <confdefs.h | sed '
+s/'"$ac_delim"'/"\\\
+"/g' >>$CONFIG_STATUS || ac_write_fail=1
+
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+  for (key in D) D_is_set[key] = 1
+  FS = ""
+}
+/^[\t ]*#[\t ]*(define|undef)[\t ]+$ac_word_re([\t (]|\$)/ {
+  line = \$ 0
+  split(line, arg, " ")
+  if (arg[1] == "#") {
+    defundef = arg[2]
+    mac1 = arg[3]
+  } else {
+    defundef = substr(arg[1], 2)
+    mac1 = arg[2]
+  }
+  split(mac1, mac2, "(") #)
+  macro = mac2[1]
+  prefix = substr(line, 1, index(line, defundef) - 1)
+  if (D_is_set[macro]) {
+    # Preserve the white space surrounding the "#".
+    print prefix "define", macro P[macro] D[macro]
+    next
+  } else {
+    # Replace #undef with comments.  This is necessary, for example,
+    # in the case of _POSIX_SOURCE, which is predefined and required
+    # on some systems where configure will not decide to define it.
+    if (defundef == "undef") {
+      print "/*", prefix defundef, macro, "*/"
+      next
+    }
+  }
+}
+{ print }
+_ACAWK
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+  as_fn_error $? "could not setup config headers machinery" "$LINENO" 5
+fi # test -n "$CONFIG_HEADERS"
+
+
+eval set X "  :F $CONFIG_FILES  :H $CONFIG_HEADERS    :C $CONFIG_COMMANDS"
+shift
+for ac_tag
+do
+  case $ac_tag in
+  :[FHLC]) ac_mode=$ac_tag; continue;;
+  esac
+  case $ac_mode$ac_tag in
+  :[FHL]*:*);;
+  :L* | :C*:*) as_fn_error $? "invalid tag \`$ac_tag'" "$LINENO" 5;;
+  :[FH]-) ac_tag=-:-;;
+  :[FH]*) ac_tag=$ac_tag:$ac_tag.in;;
+  esac
+  ac_save_IFS=$IFS
+  IFS=:
+  set x $ac_tag
+  IFS=$ac_save_IFS
+  shift
+  ac_file=$1
+  shift
+
+  case $ac_mode in
+  :L) ac_source=$1;;
+  :[FH])
+    ac_file_inputs=
+    for ac_f
+    do
+      case $ac_f in
+      -) ac_f="$ac_tmp/stdin";;
+      *) # Look for the file first in the build tree, then in the source tree
+	 # (if the path is not absolute).  The absolute path cannot be DOS-style,
+	 # because $ac_f cannot contain `:'.
+	 test -f "$ac_f" ||
+	   case $ac_f in
+	   [\\/$]*) false;;
+	   *) test -f "$srcdir/$ac_f" && ac_f="$srcdir/$ac_f";;
+	   esac ||
+	   as_fn_error 1 "cannot find input file: \`$ac_f'" "$LINENO" 5;;
+      esac
+      case $ac_f in *\'*) ac_f=`$as_echo "$ac_f" | sed "s/'/'\\\\\\\\''/g"`;; esac
+      as_fn_append ac_file_inputs " '$ac_f'"
+    done
+
+    # Let's still pretend it is `configure' which instantiates (i.e., don't
+    # use $as_me), people would be surprised to read:
+    #    /* config.h.  Generated by config.status.  */
+    configure_input='Generated from '`
+	  $as_echo "$*" | sed 's|^[^:]*/||;s|:[^:]*/|, |g'
+	`' by configure.'
+    if test x"$ac_file" != x-; then
+      configure_input="$ac_file.  $configure_input"
+      { $as_echo "$as_me:${as_lineno-$LINENO}: creating $ac_file" >&5
+$as_echo "$as_me: creating $ac_file" >&6;}
+    fi
+    # Neutralize special characters interpreted by sed in replacement strings.
+    case $configure_input in #(
+    *\&* | *\|* | *\\* )
+       ac_sed_conf_input=`$as_echo "$configure_input" |
+       sed 's/[\\\\&|]/\\\\&/g'`;; #(
+    *) ac_sed_conf_input=$configure_input;;
+    esac
+
+    case $ac_tag in
+    *:-:* | *:-) cat >"$ac_tmp/stdin" \
+      || as_fn_error $? "could not create $ac_file" "$LINENO" 5 ;;
+    esac
+    ;;
+  esac
+
+  ac_dir=`$as_dirname -- "$ac_file" ||
+$as_expr X"$ac_file" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$ac_file" : 'X\(//\)[^/]' \| \
+	 X"$ac_file" : 'X\(//\)$' \| \
+	 X"$ac_file" : 'X\(/\)' \| . 2>/dev/null ||
+$as_echo X"$ac_file" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+  as_dir="$ac_dir"; as_fn_mkdir_p
+  ac_builddir=.
+
+case "$ac_dir" in
+.) ac_dir_suffix= ac_top_builddir_sub=. ac_top_build_prefix= ;;
+*)
+  ac_dir_suffix=/`$as_echo "$ac_dir" | sed 's|^\.[\\/]||'`
+  # A ".." for each directory in $ac_dir_suffix.
+  ac_top_builddir_sub=`$as_echo "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
+  case $ac_top_builddir_sub in
+  "") ac_top_builddir_sub=. ac_top_build_prefix= ;;
+  *)  ac_top_build_prefix=$ac_top_builddir_sub/ ;;
+  esac ;;
+esac
+ac_abs_top_builddir=$ac_pwd
+ac_abs_builddir=$ac_pwd$ac_dir_suffix
+# for backward compatibility:
+ac_top_builddir=$ac_top_build_prefix
+
+case $srcdir in
+  .)  # We are building in place.
+    ac_srcdir=.
+    ac_top_srcdir=$ac_top_builddir_sub
+    ac_abs_top_srcdir=$ac_pwd ;;
+  [\\/]* | ?:[\\/]* )  # Absolute name.
+    ac_srcdir=$srcdir$ac_dir_suffix;
+    ac_top_srcdir=$srcdir
+    ac_abs_top_srcdir=$srcdir ;;
+  *) # Relative name.
+    ac_srcdir=$ac_top_build_prefix$srcdir$ac_dir_suffix
+    ac_top_srcdir=$ac_top_build_prefix$srcdir
+    ac_abs_top_srcdir=$ac_pwd/$srcdir ;;
+esac
+ac_abs_srcdir=$ac_abs_top_srcdir$ac_dir_suffix
+
+
+  case $ac_mode in
+  :F)
+  #
+  # CONFIG_FILE
+  #
+
+  case $INSTALL in
+  [\\/$]* | ?:[\\/]* ) ac_INSTALL=$INSTALL ;;
+  *) ac_INSTALL=$ac_top_build_prefix$INSTALL ;;
+  esac
+  ac_MKDIR_P=$MKDIR_P
+  case $MKDIR_P in
+  [\\/$]* | ?:[\\/]* ) ;;
+  */*) ac_MKDIR_P=$ac_top_build_prefix$MKDIR_P ;;
+  esac
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+# If the template does not know about datarootdir, expand it.
+# FIXME: This hack should be removed a few years after 2.60.
+ac_datarootdir_hack=; ac_datarootdir_seen=
+ac_sed_dataroot='
+/datarootdir/ {
+  p
+  q
+}
+/@datadir@/p
+/@docdir@/p
+/@infodir@/p
+/@localedir@/p
+/@mandir@/p'
+case `eval "sed -n \"\$ac_sed_dataroot\" $ac_file_inputs"` in
+*datarootdir*) ac_datarootdir_seen=yes;;
+*@datadir@*|*@docdir@*|*@infodir@*|*@localedir@*|*@mandir@*)
+  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: $ac_file_inputs seems to ignore the --datarootdir setting" >&5
+$as_echo "$as_me: WARNING: $ac_file_inputs seems to ignore the --datarootdir setting" >&2;}
+_ACEOF
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+  ac_datarootdir_hack='
+  s&@datadir@&$datadir&g
+  s&@docdir@&$docdir&g
+  s&@infodir@&$infodir&g
+  s&@localedir@&$localedir&g
+  s&@mandir@&$mandir&g
+  s&\\\${datarootdir}&$datarootdir&g' ;;
+esac
+_ACEOF
+
+# Neutralize VPATH when `$srcdir' = `.'.
+# Shell code in configure.ac might set extrasub.
+# FIXME: do we really want to maintain this feature?
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+ac_sed_extra="$ac_vpsub
+$extrasub
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+:t
+/@[a-zA-Z_][a-zA-Z_0-9]*@/!b
+s|@configure_input@|$ac_sed_conf_input|;t t
+s&@top_builddir@&$ac_top_builddir_sub&;t t
+s&@top_build_prefix@&$ac_top_build_prefix&;t t
+s&@srcdir@&$ac_srcdir&;t t
+s&@abs_srcdir@&$ac_abs_srcdir&;t t
+s&@top_srcdir@&$ac_top_srcdir&;t t
+s&@abs_top_srcdir@&$ac_abs_top_srcdir&;t t
+s&@builddir@&$ac_builddir&;t t
+s&@abs_builddir@&$ac_abs_builddir&;t t
+s&@abs_top_builddir@&$ac_abs_top_builddir&;t t
+s&@INSTALL@&$ac_INSTALL&;t t
+s&@MKDIR_P@&$ac_MKDIR_P&;t t
+$ac_datarootdir_hack
+"
+eval sed \"\$ac_sed_extra\" "$ac_file_inputs" | $AWK -f "$ac_tmp/subs.awk" \
+  >$ac_tmp/out || as_fn_error $? "could not create $ac_file" "$LINENO" 5
+
+test -z "$ac_datarootdir_hack$ac_datarootdir_seen" &&
+  { ac_out=`sed -n '/\${datarootdir}/p' "$ac_tmp/out"`; test -n "$ac_out"; } &&
+  { ac_out=`sed -n '/^[	 ]*datarootdir[	 ]*:*=/p' \
+      "$ac_tmp/out"`; test -z "$ac_out"; } &&
+  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: $ac_file contains a reference to the variable \`datarootdir'
+which seems to be undefined.  Please make sure it is defined" >&5
+$as_echo "$as_me: WARNING: $ac_file contains a reference to the variable \`datarootdir'
+which seems to be undefined.  Please make sure it is defined" >&2;}
+
+  rm -f "$ac_tmp/stdin"
+  case $ac_file in
+  -) cat "$ac_tmp/out" && rm -f "$ac_tmp/out";;
+  *) rm -f "$ac_file" && mv "$ac_tmp/out" "$ac_file";;
+  esac \
+  || as_fn_error $? "could not create $ac_file" "$LINENO" 5
+ ;;
+  :H)
+  #
+  # CONFIG_HEADER
+  #
+  if test x"$ac_file" != x-; then
+    {
+      $as_echo "/* $configure_input  */" \
+      && eval '$AWK -f "$ac_tmp/defines.awk"' "$ac_file_inputs"
+    } >"$ac_tmp/config.h" \
+      || as_fn_error $? "could not create $ac_file" "$LINENO" 5
+    if diff "$ac_file" "$ac_tmp/config.h" >/dev/null 2>&1; then
+      { $as_echo "$as_me:${as_lineno-$LINENO}: $ac_file is unchanged" >&5
+$as_echo "$as_me: $ac_file is unchanged" >&6;}
+    else
+      rm -f "$ac_file"
+      mv "$ac_tmp/config.h" "$ac_file" \
+	|| as_fn_error $? "could not create $ac_file" "$LINENO" 5
+    fi
+  else
+    $as_echo "/* $configure_input  */" \
+      && eval '$AWK -f "$ac_tmp/defines.awk"' "$ac_file_inputs" \
+      || as_fn_error $? "could not create -" "$LINENO" 5
+  fi
+# Compute "$ac_file"'s index in $config_headers.
+_am_arg="$ac_file"
+_am_stamp_count=1
+for _am_header in $config_headers :; do
+  case $_am_header in
+    $_am_arg | $_am_arg:* )
+      break ;;
+    * )
+      _am_stamp_count=`expr $_am_stamp_count + 1` ;;
+  esac
+done
+echo "timestamp for $_am_arg" >`$as_dirname -- "$_am_arg" ||
+$as_expr X"$_am_arg" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$_am_arg" : 'X\(//\)[^/]' \| \
+	 X"$_am_arg" : 'X\(//\)$' \| \
+	 X"$_am_arg" : 'X\(/\)' \| . 2>/dev/null ||
+$as_echo X"$_am_arg" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`/stamp-h$_am_stamp_count
+ ;;
+
+  :C)  { $as_echo "$as_me:${as_lineno-$LINENO}: executing $ac_file commands" >&5
+$as_echo "$as_me: executing $ac_file commands" >&6;}
+ ;;
+  esac
+
+
+  case $ac_file$ac_mode in
+    "depfiles":C) test x"$AMDEP_TRUE" != x"" || {
+  # Older Autoconf quotes --file arguments for eval, but not when files
+  # are listed without --file.  Let's play safe and only enable the eval
+  # if we detect the quoting.
+  # TODO: see whether this extra hack can be removed once we start
+  # requiring Autoconf 2.70 or later.
+  case $CONFIG_FILES in #(
+  *\'*) :
+    eval set x "$CONFIG_FILES" ;; #(
+  *) :
+    set x $CONFIG_FILES ;; #(
+  *) :
+     ;;
+esac
+  shift
+  # Used to flag and report bootstrapping failures.
+  am_rc=0
+  for am_mf
+  do
+    # Strip MF so we end up with the name of the file.
+    am_mf=`$as_echo "$am_mf" | sed -e 's/:.*$//'`
+    # Check whether this is an Automake generated Makefile which includes
+    # dependency-tracking related rules and includes.
+    # Grep'ing the whole file directly is not great: AIX grep has a line
+    # limit of 2048, but all sed's we know have understand at least 4000.
+    sed -n 's,^am--depfiles:.*,X,p' "$am_mf" | grep X >/dev/null 2>&1 \
+      || continue
+    am_dirpart=`$as_dirname -- "$am_mf" ||
+$as_expr X"$am_mf" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$am_mf" : 'X\(//\)[^/]' \| \
+	 X"$am_mf" : 'X\(//\)$' \| \
+	 X"$am_mf" : 'X\(/\)' \| . 2>/dev/null ||
+$as_echo X"$am_mf" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+    am_filepart=`$as_basename -- "$am_mf" ||
+$as_expr X/"$am_mf" : '.*/\([^/][^/]*\)/*$' \| \
+	 X"$am_mf" : 'X\(//\)$' \| \
+	 X"$am_mf" : 'X\(/\)' \| . 2>/dev/null ||
+$as_echo X/"$am_mf" |
+    sed '/^.*\/\([^/][^/]*\)\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+    { echo "$as_me:$LINENO: cd "$am_dirpart" \
+      && sed -e '/# am--include-marker/d' "$am_filepart" \
+        | $MAKE -f - am--depfiles" >&5
+   (cd "$am_dirpart" \
+      && sed -e '/# am--include-marker/d' "$am_filepart" \
+        | $MAKE -f - am--depfiles) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); } || am_rc=$?
+  done
+  if test $am_rc -ne 0; then
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "Something went wrong bootstrapping makefile fragments
+    for automatic dependency tracking.  Try re-running configure with the
+    '--disable-dependency-tracking' option to at least be able to build
+    the package (albeit without support for automatic dependency tracking).
+See \`config.log' for more details" "$LINENO" 5; }
+  fi
+  { am_dirpart=; unset am_dirpart;}
+  { am_filepart=; unset am_filepart;}
+  { am_mf=; unset am_mf;}
+  { am_rc=; unset am_rc;}
+  rm -f conftest-deps.mk
+}
+ ;;
+    "libtool":C)
+
+    # See if we are running on zsh, and set the options that allow our
+    # commands through without removal of \ escapes.
+    if test -n "${ZSH_VERSION+set}"; then
+      setopt NO_GLOB_SUBST
+    fi
+
+    cfgfile=${ofile}T
+    trap "$RM \"$cfgfile\"; exit 1" 1 2 15
+    $RM "$cfgfile"
+
+    cat <<_LT_EOF >> "$cfgfile"
+#! $SHELL
+# Generated automatically by $as_me ($PACKAGE) $VERSION
+# Libtool was configured on host `(hostname || uname -n) 2>/dev/null | sed 1q`:
+# NOTE: Changes made to this file will be lost: look at ltmain.sh.
+
+# Provide generalized library-building support services.
+# Written by Gordon Matzigkeit, 1996
+
+# Copyright (C) 2014 Free Software Foundation, Inc.
+# This is free software; see the source for copying conditions.  There is NO
+# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+# GNU Libtool is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of of the License, or
+# (at your option) any later version.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program or library that is built
+# using GNU Libtool, you may include this file under the  same
+# distribution terms that you use for the rest of that program.
+#
+# GNU Libtool is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+# The names of the tagged configurations supported by this script.
+available_tags=''
+
+# Configured defaults for sys_lib_dlsearch_path munging.
+: \${LT_SYS_LIBRARY_PATH="$configure_time_lt_sys_library_path"}
+
+# ### BEGIN LIBTOOL CONFIG
+
+# A sed program that does not truncate output.
+SED=$lt_SED
+
+# Sed that helps us avoid accidentally triggering echo(1) options like -n.
+Xsed="\$SED -e 1s/^X//"
+
+# A grep program that handles long lines.
+GREP=$lt_GREP
+
+# An ERE matcher.
+EGREP=$lt_EGREP
+
+# A literal string matcher.
+FGREP=$lt_FGREP
+
+# Shell to use when invoking shell scripts.
+SHELL=$lt_SHELL
+
+# An echo program that protects backslashes.
+ECHO=$lt_ECHO
+
+# Which release of libtool.m4 was used?
+macro_version=$macro_version
+macro_revision=$macro_revision
+
+# Assembler program.
+AS=$lt_AS
+
+# DLL creation program.
+DLLTOOL=$lt_DLLTOOL
+
+# Object dumper program.
+OBJDUMP=$lt_OBJDUMP
+
+# Whether or not to build shared libraries.
+build_libtool_libs=$enable_shared
+
+# Whether or not to build static libraries.
+build_old_libs=$enable_static
+
+# What type of objects to build.
+pic_mode=$pic_mode
+
+# Whether or not to optimize for fast installation.
+fast_install=$enable_fast_install
+
+# Shared archive member basename,for filename based shared library versioning on AIX.
+shared_archive_member_spec=$shared_archive_member_spec
+
+# The PATH separator for the build system.
+PATH_SEPARATOR=$lt_PATH_SEPARATOR
+
+# The host system.
+host_alias=$host_alias
+host=$host
+host_os=$host_os
+
+# The build system.
+build_alias=$build_alias
+build=$build
+build_os=$build_os
+
+# A BSD- or MS-compatible name lister.
+NM=$lt_NM
+
+# Whether we need soft or hard links.
+LN_S=$lt_LN_S
+
+# What is the maximum length of a command?
+max_cmd_len=$max_cmd_len
+
+# Object file suffix (normally "o").
+objext=$ac_objext
+
+# Executable file suffix (normally "").
+exeext=$exeext
+
+# whether the shell understands "unset".
+lt_unset=$lt_unset
+
+# turn spaces into newlines.
+SP2NL=$lt_lt_SP2NL
+
+# turn newlines into spaces.
+NL2SP=$lt_lt_NL2SP
+
+# convert \$build file names to \$host format.
+to_host_file_cmd=$lt_cv_to_host_file_cmd
+
+# convert \$build files to toolchain format.
+to_tool_file_cmd=$lt_cv_to_tool_file_cmd
+
+# Method to check whether dependent libraries are shared objects.
+deplibs_check_method=$lt_deplibs_check_method
+
+# Command to use when deplibs_check_method = "file_magic".
+file_magic_cmd=$lt_file_magic_cmd
+
+# How to find potential files when deplibs_check_method = "file_magic".
+file_magic_glob=$lt_file_magic_glob
+
+# Find potential files using nocaseglob when deplibs_check_method = "file_magic".
+want_nocaseglob=$lt_want_nocaseglob
+
+# Command to associate shared and link libraries.
+sharedlib_from_linklib_cmd=$lt_sharedlib_from_linklib_cmd
+
+# The archiver.
+AR=$lt_AR
+
+# Flags to create an archive.
+AR_FLAGS=$lt_AR_FLAGS
+
+# How to feed a file listing to the archiver.
+archiver_list_spec=$lt_archiver_list_spec
+
+# A symbol stripping program.
+STRIP=$lt_STRIP
+
+# Commands used to install an old-style archive.
+RANLIB=$lt_RANLIB
+old_postinstall_cmds=$lt_old_postinstall_cmds
+old_postuninstall_cmds=$lt_old_postuninstall_cmds
+
+# Whether to use a lock for old archive extraction.
+lock_old_archive_extraction=$lock_old_archive_extraction
+
+# A C compiler.
+LTCC=$lt_CC
+
+# LTCC compiler flags.
+LTCFLAGS=$lt_CFLAGS
+
+# Take the output of nm and produce a listing of raw symbols and C names.
+global_symbol_pipe=$lt_lt_cv_sys_global_symbol_pipe
+
+# Transform the output of nm in a proper C declaration.
+global_symbol_to_cdecl=$lt_lt_cv_sys_global_symbol_to_cdecl
+
+# Transform the output of nm into a list of symbols to manually relocate.
+global_symbol_to_import=$lt_lt_cv_sys_global_symbol_to_import
+
+# Transform the output of nm in a C name address pair.
+global_symbol_to_c_name_address=$lt_lt_cv_sys_global_symbol_to_c_name_address
+
+# Transform the output of nm in a C name address pair when lib prefix is needed.
+global_symbol_to_c_name_address_lib_prefix=$lt_lt_cv_sys_global_symbol_to_c_name_address_lib_prefix
+
+# The name lister interface.
+nm_interface=$lt_lt_cv_nm_interface
+
+# Specify filename containing input files for \$NM.
+nm_file_list_spec=$lt_nm_file_list_spec
+
+# The root where to search for dependent libraries,and where our libraries should be installed.
+lt_sysroot=$lt_sysroot
+
+# Command to truncate a binary pipe.
+lt_truncate_bin=$lt_lt_cv_truncate_bin
+
+# The name of the directory that contains temporary libtool files.
+objdir=$objdir
+
+# Used to examine libraries when file_magic_cmd begins with "file".
+MAGIC_CMD=$MAGIC_CMD
+
+# Must we lock files when doing compilation?
+need_locks=$lt_need_locks
+
+# Manifest tool.
+MANIFEST_TOOL=$lt_MANIFEST_TOOL
+
+# Tool to manipulate archived DWARF debug symbol files on Mac OS X.
+DSYMUTIL=$lt_DSYMUTIL
+
+# Tool to change global to local symbols on Mac OS X.
+NMEDIT=$lt_NMEDIT
+
+# Tool to manipulate fat objects and archives on Mac OS X.
+LIPO=$lt_LIPO
+
+# ldd/readelf like tool for Mach-O binaries on Mac OS X.
+OTOOL=$lt_OTOOL
+
+# ldd/readelf like tool for 64 bit Mach-O binaries on Mac OS X 10.4.
+OTOOL64=$lt_OTOOL64
+
+# Old archive suffix (normally "a").
+libext=$libext
+
+# Shared library suffix (normally ".so").
+shrext_cmds=$lt_shrext_cmds
+
+# The commands to extract the exported symbol list from a shared archive.
+extract_expsyms_cmds=$lt_extract_expsyms_cmds
+
+# Variables whose values should be saved in libtool wrapper scripts and
+# restored at link time.
+variables_saved_for_relink=$lt_variables_saved_for_relink
+
+# Do we need the "lib" prefix for modules?
+need_lib_prefix=$need_lib_prefix
+
+# Do we need a version for libraries?
+need_version=$need_version
+
+# Library versioning type.
+version_type=$version_type
+
+# Shared library runtime path variable.
+runpath_var=$runpath_var
+
+# Shared library path variable.
+shlibpath_var=$shlibpath_var
+
+# Is shlibpath searched before the hard-coded library search path?
+shlibpath_overrides_runpath=$shlibpath_overrides_runpath
+
+# Format of library name prefix.
+libname_spec=$lt_libname_spec
+
+# List of archive names.  First name is the real one, the rest are links.
+# The last name is the one that the linker finds with -lNAME
+library_names_spec=$lt_library_names_spec
+
+# The coded name of the library, if different from the real name.
+soname_spec=$lt_soname_spec
+
+# Permission mode override for installation of shared libraries.
+install_override_mode=$lt_install_override_mode
+
+# Command to use after installation of a shared archive.
+postinstall_cmds=$lt_postinstall_cmds
+
+# Command to use after uninstallation of a shared archive.
+postuninstall_cmds=$lt_postuninstall_cmds
+
+# Commands used to finish a libtool library installation in a directory.
+finish_cmds=$lt_finish_cmds
+
+# As "finish_cmds", except a single script fragment to be evaled but
+# not shown.
+finish_eval=$lt_finish_eval
+
+# Whether we should hardcode library paths into libraries.
+hardcode_into_libs=$hardcode_into_libs
+
+# Compile-time system search path for libraries.
+sys_lib_search_path_spec=$lt_sys_lib_search_path_spec
+
+# Detected run-time system search path for libraries.
+sys_lib_dlsearch_path_spec=$lt_configure_time_dlsearch_path
+
+# Explicit LT_SYS_LIBRARY_PATH set during ./configure time.
+configure_time_lt_sys_library_path=$lt_configure_time_lt_sys_library_path
+
+# Whether dlopen is supported.
+dlopen_support=$enable_dlopen
+
+# Whether dlopen of programs is supported.
+dlopen_self=$enable_dlopen_self
+
+# Whether dlopen of statically linked programs is supported.
+dlopen_self_static=$enable_dlopen_self_static
+
+# Commands to strip libraries.
+old_striplib=$lt_old_striplib
+striplib=$lt_striplib
+
+
+# The linker used to build libraries.
+LD=$lt_LD
+
+# How to create reloadable object files.
+reload_flag=$lt_reload_flag
+reload_cmds=$lt_reload_cmds
+
+# Commands used to build an old-style archive.
+old_archive_cmds=$lt_old_archive_cmds
+
+# A language specific compiler.
+CC=$lt_compiler
+
+# Is the compiler the GNU compiler?
+with_gcc=$GCC
+
+# Compiler flag to turn off builtin functions.
+no_builtin_flag=$lt_lt_prog_compiler_no_builtin_flag
+
+# Additional compiler flags for building library objects.
+pic_flag=$lt_lt_prog_compiler_pic
+
+# How to pass a linker flag through the compiler.
+wl=$lt_lt_prog_compiler_wl
+
+# Compiler flag to prevent dynamic linking.
+link_static_flag=$lt_lt_prog_compiler_static
+
+# Does compiler simultaneously support -c and -o options?
+compiler_c_o=$lt_lt_cv_prog_compiler_c_o
+
+# Whether or not to add -lc for building shared libraries.
+build_libtool_need_lc=$archive_cmds_need_lc
+
+# Whether or not to disallow shared libs when runtime libs are static.
+allow_libtool_libs_with_static_runtimes=$enable_shared_with_static_runtimes
+
+# Compiler flag to allow reflexive dlopens.
+export_dynamic_flag_spec=$lt_export_dynamic_flag_spec
+
+# Compiler flag to generate shared objects directly from archives.
+whole_archive_flag_spec=$lt_whole_archive_flag_spec
+
+# Whether the compiler copes with passing no objects directly.
+compiler_needs_object=$lt_compiler_needs_object
+
+# Create an old-style archive from a shared archive.
+old_archive_from_new_cmds=$lt_old_archive_from_new_cmds
+
+# Create a temporary old-style archive to link instead of a shared archive.
+old_archive_from_expsyms_cmds=$lt_old_archive_from_expsyms_cmds
+
+# Commands used to build a shared archive.
+archive_cmds=$lt_archive_cmds
+archive_expsym_cmds=$lt_archive_expsym_cmds
+
+# Commands used to build a loadable module if different from building
+# a shared archive.
+module_cmds=$lt_module_cmds
+module_expsym_cmds=$lt_module_expsym_cmds
+
+# Whether we are building with GNU ld or not.
+with_gnu_ld=$lt_with_gnu_ld
+
+# Flag that allows shared libraries with undefined symbols to be built.
+allow_undefined_flag=$lt_allow_undefined_flag
+
+# Flag that enforces no undefined symbols.
+no_undefined_flag=$lt_no_undefined_flag
+
+# Flag to hardcode \$libdir into a binary during linking.
+# This must work even if \$libdir does not exist
+hardcode_libdir_flag_spec=$lt_hardcode_libdir_flag_spec
+
+# Whether we need a single "-rpath" flag with a separated argument.
+hardcode_libdir_separator=$lt_hardcode_libdir_separator
+
+# Set to "yes" if using DIR/libNAME\$shared_ext during linking hardcodes
+# DIR into the resulting binary.
+hardcode_direct=$hardcode_direct
+
+# Set to "yes" if using DIR/libNAME\$shared_ext during linking hardcodes
+# DIR into the resulting binary and the resulting library dependency is
+# "absolute",i.e impossible to change by setting \$shlibpath_var if the
+# library is relocated.
+hardcode_direct_absolute=$hardcode_direct_absolute
+
+# Set to "yes" if using the -LDIR flag during linking hardcodes DIR
+# into the resulting binary.
+hardcode_minus_L=$hardcode_minus_L
+
+# Set to "yes" if using SHLIBPATH_VAR=DIR during linking hardcodes DIR
+# into the resulting binary.
+hardcode_shlibpath_var=$hardcode_shlibpath_var
+
+# Set to "yes" if building a shared library automatically hardcodes DIR
+# into the library and all subsequent libraries and executables linked
+# against it.
+hardcode_automatic=$hardcode_automatic
+
+# Set to yes if linker adds runtime paths of dependent libraries
+# to runtime path list.
+inherit_rpath=$inherit_rpath
+
+# Whether libtool must link a program against all its dependency libraries.
+link_all_deplibs=$link_all_deplibs
+
+# Set to "yes" if exported symbols are required.
+always_export_symbols=$always_export_symbols
+
+# The commands to list exported symbols.
+export_symbols_cmds=$lt_export_symbols_cmds
+
+# Symbols that should not be listed in the preloaded symbols.
+exclude_expsyms=$lt_exclude_expsyms
+
+# Symbols that must always be exported.
+include_expsyms=$lt_include_expsyms
+
+# Commands necessary for linking programs (against libraries) with templates.
+prelink_cmds=$lt_prelink_cmds
+
+# Commands necessary for finishing linking programs.
+postlink_cmds=$lt_postlink_cmds
+
+# Specify filename containing input files.
+file_list_spec=$lt_file_list_spec
+
+# How to hardcode a shared library path into an executable.
+hardcode_action=$hardcode_action
+
+# ### END LIBTOOL CONFIG
+
+_LT_EOF
+
+    cat <<'_LT_EOF' >> "$cfgfile"
+
+# ### BEGIN FUNCTIONS SHARED WITH CONFIGURE
+
+# func_munge_path_list VARIABLE PATH
+# -----------------------------------
+# VARIABLE is name of variable containing _space_ separated list of
+# directories to be munged by the contents of PATH, which is string
+# having a format:
+# "DIR[:DIR]:"
+#       string "DIR[ DIR]" will be prepended to VARIABLE
+# ":DIR[:DIR]"
+#       string "DIR[ DIR]" will be appended to VARIABLE
+# "DIRP[:DIRP]::[DIRA:]DIRA"
+#       string "DIRP[ DIRP]" will be prepended to VARIABLE and string
+#       "DIRA[ DIRA]" will be appended to VARIABLE
+# "DIR[:DIR]"
+#       VARIABLE will be replaced by "DIR[ DIR]"
+func_munge_path_list ()
+{
+    case x$2 in
+    x)
+        ;;
+    *:)
+        eval $1=\"`$ECHO $2 | $SED 's/:/ /g'` \$$1\"
+        ;;
+    x:*)
+        eval $1=\"\$$1 `$ECHO $2 | $SED 's/:/ /g'`\"
+        ;;
+    *::*)
+        eval $1=\"\$$1\ `$ECHO $2 | $SED -e 's/.*:://' -e 's/:/ /g'`\"
+        eval $1=\"`$ECHO $2 | $SED -e 's/::.*//' -e 's/:/ /g'`\ \$$1\"
+        ;;
+    *)
+        eval $1=\"`$ECHO $2 | $SED 's/:/ /g'`\"
+        ;;
+    esac
+}
+
+
+# Calculate cc_basename.  Skip known compiler wrappers and cross-prefix.
+func_cc_basename ()
+{
+    for cc_temp in $*""; do
+      case $cc_temp in
+        compile | *[\\/]compile | ccache | *[\\/]ccache ) ;;
+        distcc | *[\\/]distcc | purify | *[\\/]purify ) ;;
+        \-*) ;;
+        *) break;;
+      esac
+    done
+    func_cc_basename_result=`$ECHO "$cc_temp" | $SED "s%.*/%%; s%^$host_alias-%%"`
+}
+
+
+# ### END FUNCTIONS SHARED WITH CONFIGURE
+
+_LT_EOF
+
+  case $host_os in
+  aix3*)
+    cat <<\_LT_EOF >> "$cfgfile"
+# AIX sometimes has problems with the GCC collect2 program.  For some
+# reason, if we set the COLLECT_NAMES environment variable, the problems
+# vanish in a puff of smoke.
+if test set != "${COLLECT_NAMES+set}"; then
+  COLLECT_NAMES=
+  export COLLECT_NAMES
+fi
+_LT_EOF
+    ;;
+  esac
+
+
+ltmain=$ac_aux_dir/ltmain.sh
+
+
+  # We use sed instead of cat because bash on DJGPP gets confused if
+  # if finds mixed CR/LF and LF-only lines.  Since sed operates in
+  # text mode, it properly converts lines to CR/LF.  This bash problem
+  # is reportedly fixed, but why not run on old versions too?
+  sed '$q' "$ltmain" >> "$cfgfile" \
+     || (rm -f "$cfgfile"; exit 1)
+
+   mv -f "$cfgfile" "$ofile" ||
+    (rm -f "$ofile" && cp "$cfgfile" "$ofile" && rm -f "$cfgfile")
+  chmod +x "$ofile"
+
+ ;;
+    "libpng-config":F) chmod +x libpng-config ;;
+
+  esac
+done # for ac_tag
+
+
+as_fn_exit 0
+_ACEOF
+ac_clean_files=$ac_clean_files_save
+
+test $ac_write_fail = 0 ||
+  as_fn_error $? "write failure creating $CONFIG_STATUS" "$LINENO" 5
+
+
+# configure is writing to config.log, and then calls config.status.
+# config.status does its own redirection, appending to config.log.
+# Unfortunately, on DOS this fails, as config.log is still kept open
+# by configure, so config.status won't be able to write to it; its
+# output is simply discarded.  So we exec the FD to /dev/null,
+# effectively closing config.log, so it can be properly (re)opened and
+# appended to by config.status.  When coming back to configure, we
+# need to make the FD available again.
+if test "$no_create" != yes; then
+  ac_cs_success=:
+  ac_config_status_args=
+  test "$silent" = yes &&
+    ac_config_status_args="$ac_config_status_args --quiet"
+  exec 5>/dev/null
+  $SHELL $CONFIG_STATUS $ac_config_status_args || ac_cs_success=false
+  exec 5>>config.log
+  # Use ||, not &&, to avoid exiting from the if with $? = 1, which
+  # would make configure fail if this is the last instruction.
+  $ac_cs_success || as_fn_exit 1
+fi
+if test -n "$ac_unrecognized_opts" && test "$enable_option_checking" != no; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: unrecognized options: $ac_unrecognized_opts" >&5
+$as_echo "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2;}
+fi
+
diff --git a/extern/libpng/configure.ac b/extern/libpng/configure.ac
new file mode 100644
index 0000000000..52dba94b4b
--- /dev/null
+++ b/extern/libpng/configure.ac
@@ -0,0 +1,532 @@
+# configure.ac
+
+# Copyright (c) 2018 Cosmin Truta
+# Copyright (c) 2004-2016 Glenn Randers-Pehrson
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+dnl Process this file with autoconf to produce a configure script.
+dnl
+dnl Minor upgrades (compatible ABI): increment the package version
+dnl (third field in two places below) and set the PNGLIB_RELEASE
+dnl variable.
+dnl
+dnl Major upgrades (incompatible ABI): increment the package major
+dnl version (second field, or first if desired), set the minor
+dnl to 0, set PNGLIB_MAJOR below *and* follow the instructions in
+dnl Makefile.am to upgrade the package name.
+
+dnl This is here to prevent earlier autoconf from being used, it
+dnl should not be necessary to regenerate configure if the time
+dnl stamps are correct
+AC_PREREQ([2.68])
+
+dnl Version number stuff here:
+
+AC_INIT([libpng],[1.6.37],[png-mng-implement@lists.sourceforge.net])
+AC_CONFIG_MACRO_DIR([scripts])
+
+# libpng does not follow GNU file name conventions (hence 'foreign')
+# color-tests requires automake 1.11 or later
+# silent-rules requires automake 1.11 or later
+# dist-xz requires automake 1.11 or later
+# 1.12.2 fixes a security issue in 1.11.2 and 1.12.1
+# 1.13 is required for parallel tests
+AM_INIT_AUTOMAKE([1.13 foreign dist-xz color-tests silent-rules subdir-objects])
+# The following line causes --disable-maintainer-mode to be the default to
+# configure. This is necessary because libpng distributions cannot rely on the
+# time stamps of the autotools generated files being correct
+AM_MAINTAINER_MODE
+
+dnl configure.ac and Makefile.am expect automake 1.11.2 or a compatible later
+dnl version; aclocal.m4 will generate a failure if you use a prior version of
+dnl automake, so the following is not necessary (and is not defined anyway):
+dnl AM_PREREQ([1.11.2])
+dnl stop configure from automagically running automake
+
+PNGLIB_VERSION=1.6.37
+PNGLIB_MAJOR=1
+PNGLIB_MINOR=6
+PNGLIB_RELEASE=37
+
+dnl End of version number stuff
+
+AC_CONFIG_SRCDIR([pngget.c])
+AC_CONFIG_HEADERS([config.h])
+
+# Checks for programs.
+AC_LANG([C])
+AC_PROG_CC
+AM_PROG_AS
+LT_PATH_LD
+AC_PROG_CPP
+AC_PROG_AWK
+AC_PROG_INSTALL
+AC_PROG_LN_S
+AC_PROG_MAKE_SET
+
+dnl libtool/libtoolize; version 2.4.2 is the tested version. This or any
+dnl compatible later version may be used
+LT_INIT([win32-dll])
+LT_PREREQ([2.4.2])
+
+# Some awks crash when confronted with pnglibconf.dfa, do a test run now
+# to make sure this doesn't happen
+AC_MSG_CHECKING([that AWK works])
+if ${AWK} -f ${srcdir}/scripts/options.awk out="/dev/null" version=search\
+   ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+   ${srcdir}/pngusr.dfa 1>&2
+then
+   AC_MSG_RESULT([ok])
+else
+   AC_MSG_FAILURE([failed], 1)
+fi
+
+# This is a remnant of the old cc -E validation, where it may have been
+# necessary to use a different preprocessor for .dfn files
+DFNCPP="$CPP"
+AC_SUBST(DFNCPP)
+
+# -Werror cannot be passed to GCC in CFLAGS because configure will fail (it
+# checks the compiler with a program that generates a warning), add the
+# following option to deal with this
+AC_ARG_VAR(PNG_COPTS,
+   [additional flags for the C compiler, use this for options that would]
+   [cause configure itself to fail])
+AC_ARG_ENABLE(werror,
+   AS_HELP_STRING([[[--enable-werror[=OPT]]]],
+      [Pass -Werror or the given argument to the compiler if it is supported]),
+   [test "$enable_werror" = "yes" && enable_werror="-Werror"
+    if test "$enable_werror" != "no"; then
+      sav_CFLAGS="$CFLAGS"
+      CFLAGS="$enable_werror $CFLAGS"
+      AC_MSG_CHECKING([if the compiler allows $enable_werror])
+      AC_COMPILE_IFELSE(
+         [AC_LANG_SOURCE([
+            [int main(int argc, char **argv){]
+            [return argv[argc-1][0];]
+            [}]])],
+         AC_MSG_RESULT(yes)
+         PNG_COPTS="$PNG_COPTS $enable_werror",
+         AC_MSG_RESULT(no))
+      CFLAGS="$sav_CFLAGS"
+    fi],)
+
+# For GCC 5 the default mode for C is -std=gnu11 instead of -std=gnu89
+# In pngpriv.h we request just the POSIX 1003.1 and C89 APIs by defining _POSIX_SOURCE to 1
+# This is incompatible with the new default mode, so we test for that and force the 
+# "-std=c89" compiler option:
+AC_MSG_CHECKING([if we need to force back C standard to C89])
+AC_COMPILE_IFELSE(
+   [AC_LANG_PROGRAM([
+      [#define _POSIX_SOURCE 1]
+      [#include <stdio.h>]
+   ])],
+   AC_MSG_RESULT(no),[
+      if test "x$GCC" != "xyes"; then
+         AC_MSG_ERROR(
+            [Forcing back to C89 is required but the flags are only known for GCC])
+      fi
+   AC_MSG_RESULT(yes)
+   CFLAGS="$CFLAGS -std=c89"
+])
+
+# Checks for header files.
+AC_HEADER_STDC
+
+# Checks for typedefs, structures, and compiler characteristics.
+AC_C_CONST
+AC_TYPE_SIZE_T
+AC_STRUCT_TM
+AC_C_RESTRICT
+
+# Checks for library functions.
+AC_FUNC_STRTOD
+AC_CHECK_FUNCS([pow], , AC_CHECK_LIB(m, pow, , AC_MSG_ERROR(cannot find pow)) )
+
+# Some later POSIX 1003.1 functions are required for test programs, failure here
+# is soft (the corresponding test program is not built).
+AC_CHECK_FUNC([clock_gettime],,[AC_MSG_WARN([not building timepng])])
+AM_CONDITIONAL([HAVE_CLOCK_GETTIME], [test "$ac_cv_func_clock_gettime" = "yes"])
+
+AC_ARG_WITH(zlib-prefix,
+   AS_HELP_STRING([[[--with-zlib-prefix]]],
+      [prefix that may have been used in installed zlib]),
+      [ZPREFIX=${withval}],
+      [ZPREFIX='z_'])
+AC_CHECK_LIB(z, zlibVersion, ,
+    AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, , AC_MSG_ERROR(zlib not installed)))
+
+# The following is for pngvalid, to ensure it catches FP errors even on
+# platforms that don't enable FP exceptions, the function appears in the math
+# library (typically), it's not an error if it is not found.
+AC_CHECK_LIB([m], [feenableexcept])
+AC_CHECK_FUNCS([feenableexcept])
+
+AC_MSG_CHECKING([if using Solaris linker])
+SLD=`$LD --version 2>&1 | grep Solaris`
+if test "$SLD"; then
+    have_solaris_ld=yes
+    AC_MSG_RESULT(yes)
+else
+    have_solaris_ld=no
+    AC_MSG_RESULT(no)
+fi
+AM_CONDITIONAL(HAVE_SOLARIS_LD, test "$have_solaris_ld" = "yes")
+
+AC_MSG_CHECKING([if libraries can be versioned])
+# Special case for PE/COFF platforms: ld reports
+# support for version-script, but doesn't actually
+# DO anything with it.
+case $host in
+*cygwin* | *mingw32* | *interix* )
+    have_ld_version_script=no
+    AC_MSG_RESULT(no)
+;;
+* )
+
+if test "$have_solaris_ld" = "yes"; then
+    GLD=`$LD --help < /dev/null 2>&1 | grep 'M mapfile'`
+else
+    GLD=`$LD --help < /dev/null 2>/dev/null | grep version-script`
+fi
+
+if test "$GLD"; then
+    have_ld_version_script=yes
+    AC_MSG_RESULT(yes)
+else
+    have_ld_version_script=no
+    AC_MSG_RESULT(no)
+    AC_MSG_WARN(*** You have not enabled versioned symbols.)
+fi
+;;
+esac
+
+AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
+
+if test "$have_ld_version_script" = "yes"; then
+    AC_MSG_CHECKING([for symbol prefix])
+    SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
+                  | ${CPP-${CC-gcc} -E} - 2>&1 \
+                  | ${EGREP-grep} "^PREFIX=" \
+                  | ${SED-sed} -e "s:^PREFIX=::" -e "s:__USER_LABEL_PREFIX__::"`
+    AC_SUBST(SYMBOL_PREFIX)
+    AC_MSG_RESULT($SYMBOL_PREFIX)
+fi
+
+# Substitutions for .in files
+AC_SUBST(PNGLIB_VERSION)
+AC_SUBST(PNGLIB_MAJOR)
+AC_SUBST(PNGLIB_MINOR)
+AC_SUBST(PNGLIB_RELEASE)
+
+# Additional arguments (and substitutions)
+# Allow the pkg-config directory to be set
+AC_ARG_WITH(pkgconfigdir,
+   AS_HELP_STRING([[[--with-pkgconfigdir]]],
+      [Use the specified pkgconfig dir (default is libdir/pkgconfig)]),
+   [pkgconfigdir=${withval}],
+   [pkgconfigdir='${libdir}/pkgconfig'])
+
+AC_SUBST([pkgconfigdir])
+AC_MSG_NOTICE([[pkgconfig directory is ${pkgconfigdir}]])
+
+# Make the *-config binary config scripts optional
+AC_ARG_WITH(binconfigs,
+   AS_HELP_STRING([[[--with-binconfigs]]],
+      [Generate shell libpng-config scripts as well as pkg-config data]
+      [@<:@default=yes@:>@]),
+   [if test "${withval}" = no; then
+      binconfigs=
+      AC_MSG_NOTICE([[libpng-config scripts will not be built]])
+    else
+      binconfigs='${binconfigs}'
+    fi],
+   [binconfigs='${binconfigs}'])
+AC_SUBST([binconfigs])
+
+# Support for prefixes to the API function names; this will generate defines
+# at the start of the build to rename exported library functions
+AC_ARG_WITH(libpng-prefix,
+   AS_HELP_STRING([[[--with-libpng-prefix]]],
+      [prefix libpng exported function (API) names with the given value]),
+   [if test "${withval:-no}" != "no"; then
+      AC_SUBST([PNG_PREFIX], [${withval}])
+    fi])
+AM_CONDITIONAL([DO_PNG_PREFIX], [test "${with_libpng_prefix:-no}" != "no"])
+
+# Control over what links are made for installed files.  Versioned files are
+# always installed, when the following options are turned on corresponding
+# unversioned links are also created (normally as symbolic links):
+AC_ARG_ENABLE([unversioned-links],
+   AS_HELP_STRING([[[--enable-unversioned-links]]],
+      [Installed libpng header files are placed in a versioned subdirectory]
+      [and installed libpng library (including DLL) files are versioned.]
+      [If this option is enabled unversioned links will be created pointing to]
+      [the corresponding installed files.  If you use libpng.pc or]
+      [libpng-config for all builds you do not need these links, but if you]
+      [compile programs directly they will typically #include <png.h> and]
+      [link with -lpng; in that case you need the links.]
+      [The links can be installed manually using 'make install-header-links']
+      [and 'make install-library-links' and can be removed using the]
+      [corresponding uninstall- targets.  If you do enable this option every]
+      [libpng 'make install' will recreate the links to point to the just]
+      [installed version of libpng.  The default is to create the links;]
+      [use --disable-unversioned-links to change this]))
+
+# The AM_CONDITIONAL test is written so that the default is enabled;
+# --disable-unversioned-links must be given to turn the option off.
+AM_CONDITIONAL([DO_INSTALL_LINKS],[test "$enable_unversioned_links" != "no"])
+
+AC_ARG_ENABLE([unversioned-libpng-pc],
+   AS_HELP_STRING([[[--enable-unversioned-libpng-pc]]],
+      [Install the configuration file 'libpng.pc' as a link to the versioned]
+      [version.  This is done by default - use --disable-unversioned-libpng-pc]
+      [to change this.]))
+AM_CONDITIONAL([DO_INSTALL_LIBPNG_PC],
+   [test "$enable_unversioned_libpng_pc" != "no"])
+
+AC_ARG_ENABLE([unversioned-libpng-config],
+   AS_HELP_STRING([[[--enable-unversioned-libpng-config]]],
+      [Install the configuration file 'libpng-config' as a link to the]
+      [versioned version.  This is done by default - use]
+      [--disable-unversioned-libpng-config to change this.]))
+AM_CONDITIONAL([DO_INSTALL_LIBPNG_CONFIG],
+   [test "$enable_unversioned_libpng_config" != "no"])
+
+# HOST SPECIFIC OPTIONS
+# =====================
+#
+# DEFAULT
+# =======
+#
+AC_ARG_ENABLE([hardware-optimizations],
+   AS_HELP_STRING([[[--enable-hardware-optimizations]]],
+      [Enable hardware optimizations: =no/off, yes/on:]),
+   [case "$enableval" in
+      no|off)
+         # disable hardware optimization on all systems:
+         enable_arm_neon=no
+         AC_DEFINE([PNG_ARM_NEON_OPT], [0],
+           [Disable ARM_NEON optimizations])
+         enable_mips_msa=no
+         AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
+           [Disable MIPS_MSA optimizations])
+         enable_powerpc_vsx=no
+         AC_DEFINE([PNG_POWERPC_VSX_OPT], [0],
+           [Disable POWERPC VSX optimizations])
+         enable_intel_sse=no
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [0],
+           [Disable INTEL_SSE optimizations])
+         ;;
+      *)
+         # allow enabling hardware optimization on any system:
+         case "$host_cpu" in
+            arm*|aarch64*)
+              enable_arm_neon=yes
+              AC_DEFINE([PNG_ARM_NEON_OPT], [0],
+                [Enable ARM_NEON optimizations])
+              ;;
+            mipsel*|mips64el*)
+              enable_mips_msa=yes
+              AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
+                [Enable MIPS_MSA optimizations])
+              ;;
+            i?86|x86_64)
+              enable_intel_sse=yes
+              AC_DEFINE([PNG_INTEL_SSE_OPT], [1],
+                [Enable Intel SSE optimizations])
+              ;;
+            powerpc*|ppc64*)
+              enable_powerpc_vsx=yes
+              AC_DEFINE([PNG_POWERPC_VSX_OPT], [2],
+                [Enable POWERPC VSX optimizations])
+              ;;
+         esac
+         ;;
+   esac])
+
+# ARM
+# ===
+#
+# ARM NEON (SIMD) support.
+
+AC_ARG_ENABLE([arm-neon],
+   AS_HELP_STRING([[[--enable-arm-neon]]],
+      [Enable ARM NEON optimizations: =no/off, check, api, yes/on:]
+      [no/off: disable the optimizations; check: use internal checking code]
+      [(deprecated and poorly supported); api: disable by default, enable by]
+      [a call to png_set_option; yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __ARM_NEON__ systems:
+         AC_DEFINE([PNG_ARM_NEON_OPT], [0],
+                   [Disable ARM Neon optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_arm_neon=no;;
+      check)
+         AC_DEFINE([PNG_ARM_NEON_CHECK_SUPPORTED], [],
+                   [Check for ARM Neon support at run-time]);;
+      api)
+         AC_DEFINE([PNG_ARM_NEON_API_SUPPORTED], [],
+                   [Turn on ARM Neon optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_ARM_NEON_OPT], [2],
+                   [Enable ARM Neon optimizations])
+         AC_MSG_WARN([--enable-arm-neon: please specify 'check' or 'api', if]
+            [you want the optimizations unconditionally pass -mfpu=neon]
+            [to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-arm-neon=${enable_arm_neon}: invalid value])
+   esac])
+
+# Add ARM specific files to all builds where the host_cpu is arm ('arm*') or
+# where ARM optimizations were explicitly requested (this allows a fallback if a
+# future host CPU does not match 'arm*')
+
+AM_CONDITIONAL([PNG_ARM_NEON],
+   [test "$enable_arm_neon" != 'no' &&
+    case "$host_cpu" in
+      arm*|aarch64*) :;;
+      *)    test "$enable_arm_neon" != '';;
+    esac])
+
+# MIPS
+# ===
+#
+# MIPS MSA (SIMD) support.
+
+AC_ARG_ENABLE([mips-msa],
+   AS_HELP_STRING([[[--enable-mips-msa]]],
+      [Enable MIPS MSA optimizations: =no/off, check, api, yes/on:]
+      [no/off: disable the optimizations; check: use internal checking code]
+      [(deprecated and poorly supported); api: disable by default, enable by]
+      [a call to png_set_option; yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __mips_msa systems:
+         AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
+                   [Disable MIPS MSA optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_mips_msa=no;;
+      check)
+         AC_DEFINE([PNG_MIPS_MSA_CHECK_SUPPORTED], [],
+                   [Check for MIPS MSA support at run-time]);;
+      api)
+         AC_DEFINE([PNG_MIPS_MSA_API_SUPPORTED], [],
+                   [Turn on MIPS MSA optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_MIPS_MSA_OPT], [2],
+                   [Enable MIPS MSA optimizations])
+         AC_MSG_WARN([--enable-mips-msa: please specify 'check' or 'api', if]
+            [you want the optimizations unconditionally pass '-mmsa -mfp64']
+            [to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-mips-msa=${enable_mips_msa}: invalid value])
+   esac])
+
+# Add MIPS specific files to all builds where the host_cpu is mips ('mips*') or
+# where MIPS optimizations were explicitly requested (this allows a fallback if a
+# future host CPU does not match 'mips*')
+
+AM_CONDITIONAL([PNG_MIPS_MSA],
+   [test "$enable_mips_msa" != 'no' &&
+    case "$host_cpu" in
+      mipsel*|mips64el*) :;;
+    esac])
+
+# INTEL
+# =====
+#
+# INTEL SSE (SIMD) support.
+
+AC_ARG_ENABLE([intel-sse],
+   AS_HELP_STRING([[[--enable-intel-sse]]],
+      [Enable Intel SSE optimizations: =no/off, yes/on:]
+      [no/off: disable the optimizations;]
+      [yes/on: enable the optimizations.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling:
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [0],
+                   [Disable Intel SSE optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_intel_sse=no;;
+      yes|on)
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [1],
+                   [Enable Intel SSE optimizations]);;
+      *)
+         AC_MSG_ERROR([--enable-intel-sse=${enable_intel_sse}: invalid value])
+   esac])
+
+# Add Intel specific files to all builds where the host_cpu is Intel ('x86*')
+# or where Intel optimizations were explicitly requested (this allows a
+# fallback if a future host CPU does not match 'x86*')
+AM_CONDITIONAL([PNG_INTEL_SSE],
+   [test "$enable_intel_sse" != 'no' &&
+    case "$host_cpu" in
+      i?86|x86_64) :;;
+      *)    test "$enable_intel_sse" != '';;
+    esac])
+
+# PowerPC
+# ===
+#
+# PowerPC VSX (SIMD) support.
+
+AC_ARG_ENABLE([powerpc-vsx],
+AS_HELP_STRING([[[--enable-powerpc-vsx]]],
+      [Enable POWERPC VSX optimizations: =no/off, check, api, yes/on:]
+      [no/off: disable the optimizations; check: use internal checking code]
+      [api: disable by default, enable by a call to png_set_option]
+      [yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __ppc64__ systems:
+         AC_DEFINE([PNG_POWERPC_VSX_OPT], [0],
+                   [Disable POWERPC VSX optimizations])
+         # Prevent inclusion of the platform specific files below:
+         enable_powerpc_vsx=no;;
+      check)
+         AC_DEFINE([PNG_POWERPC_VSX_CHECK_SUPPORTED], [],
+                   [Check for POWERPC VSX support at run-time])
+         AC_MSG_WARN([--enable-powerpc-vsx Please check contrib/powerpc/README file]
+            [for the list of supported OSes.]);;
+      api)
+         AC_DEFINE([PNG_POWERPC_VSX_API_SUPPORTED], [],
+                   [Turn on POWERPC VSX optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_POWERPC_VSX_OPT], [2],
+                   [Enable POWERPC VSX optimizations])
+         AC_MSG_WARN([--enable-powerpc-vsx: please specify 'check' or 'api', if]
+            [you want the optimizations unconditionally pass '-maltivec -mvsx']
+            [or '-mcpu=power8'to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-powerpc-vsx=${enable_powerpc_vsx}: invalid value])
+   esac])
+
+# Add PowerPC specific files to all builds where the host_cpu is powerpc('powerpc*') or
+# where POWERPC optimizations were explicitly requested (this allows a fallback if a
+# future host CPU does not match 'powerpc*')
+
+AM_CONDITIONAL([PNG_POWERPC_VSX],
+   [test "$enable_powerpc_vsx" != 'no' &&
+    case "$host_cpu" in
+      powerpc*|ppc64*) :;;
+    esac])
+
+
+AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])
+
+# Config files, substituting as above
+AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])
+AC_CONFIG_FILES([libpng-config:libpng-config.in],
+   [chmod +x libpng-config])
+
+AC_OUTPUT
diff --git a/extern/libpng/contrib/README.txt b/extern/libpng/contrib/README.txt
new file mode 100644
index 0000000000..97963c6d54
--- /dev/null
+++ b/extern/libpng/contrib/README.txt
@@ -0,0 +1,5 @@
+
+This "contrib" directory contains contributions which are not necessarily under
+the libpng license, although all are open source.  They are not part of
+libpng proper and are not used for building the library, although some are used
+for testing the library via "make check".
diff --git a/extern/libpng/contrib/arm-neon/README b/extern/libpng/contrib/arm-neon/README
new file mode 100644
index 0000000000..b4248cf289
--- /dev/null
+++ b/extern/libpng/contrib/arm-neon/README
@@ -0,0 +1,83 @@
+OPERATING SYSTEM SPECIFIC ARM NEON DETECTION
+--------------------------------------------
+
+Detection of the ability to execute ARM NEON on an ARM processor requires
+operating system support.  (The information is not available in user mode.)
+
+HOW TO USE THIS
+---------------
+
+This directory contains C code fragments that can be included in arm/arm_init.c
+by setting the macro PNG_ARM_NEON_FILE to the file name in "" or <> at build
+time.  This setting is not recorded in pnglibconf.h and can be changed simply by
+rebuilding arm/arm_init.o with the required macro definition.
+
+For any of this code to be used the ARM NEON code must be enabled and run time
+checks must be supported.  I.e.:
+
+#if PNG_ARM_NEON_OPT > 0
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-arm-neon=check
+
+Apart from the basic Linux implementation in contrib/arm-neon/linux.c this code
+is unsupported.  That means that it is not even compiled on a regular basis and
+may be broken in any given minor release.
+
+FILE FORMAT
+-----------
+
+Each file documents its testing status as of the last time it was tested (which
+may have been a long time ago):
+
+STATUS: one of:
+   SUPPORTED: This indicates that the file is included in the regularly
+         performed test builds and bugs are fixed when discovered.
+   COMPILED: This indicates that the code did compile at least once.  See the
+         more detailed description for the extent to which the result was
+         successful.
+   TESTED: This means the code was fully compiled into the libpng test programs
+         and these were run at least once.
+
+BUG REPORTS: an email address to which to send reports of problems
+
+The file is a fragment of C code. It should not define any 'extern' symbols;
+everything should be static.  It must define the function:
+
+static int png_have_neon(png_structp png_ptr);
+
+That function must return 1 if ARM NEON instructions are supported, 0 if not.
+It must not execute png_error unless it detects a bug.  A png_error will prevent
+the reading of the PNG and in the future, writing too.
+
+BUG REPORTS
+-----------
+
+If you mail a bug report for any file that is not SUPPORTED there may only be
+limited response.  Consider fixing it and sending a patch to fix the problem -
+this is more likely to result in action.
+
+CONTRIBUTIONS
+-------------
+
+You may send contributions of new implementations to
+png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+possible.  Obviously OS dependencies are to be expected.  If you submit code you
+must have the authors permission and it must have a license that is acceptable
+to the current maintainer; in particular that license must permit modification
+and redistribution.
+
+Please try to make the contribution a single file and give the file a clear and
+unambiguous name that identifies the target OS.  If multiple files really are
+required put them all in a sub-directory.
+
+You must also be prepared to handle bug reports from users of the code, either
+by joining the png-mng-implement mailing list or by providing an email for the
+"BUG REPORTS" entry or both.  Please make sure that the header of the file
+contains the STATUS and BUG REPORTS fields as above.
+
+Please list the OS requirements as precisely as possible.  Ideally you should
+also list the environment in which the code has been tested and certainly list
+any environments where you suspect it might not work.
diff --git a/extern/libpng/contrib/arm-neon/android-ndk.c b/extern/libpng/contrib/arm-neon/android-ndk.c
new file mode 100644
index 0000000000..fb3a4898de
--- /dev/null
+++ b/extern/libpng/contrib/arm-neon/android-ndk.c
@@ -0,0 +1,39 @@
+/* contrib/arm-neon/android-ndk.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by John Bowler, 2014.
+ * Last changed in libpng 1.6.10 [March 6, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: COMPILED, UNTESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for the Android NDK, see:
+ *
+ * Documentation:
+ *    http://www.kandroid.org/ndk/docs/CPU-ARM-NEON.html
+ *    https://code.google.com/p/android/issues/detail?id=49065
+ *
+ * NOTE: this requires that libpng is built against the Android NDK and linked
+ * with an implementation of the Android ARM 'cpu-features' library.  The code
+ * has been compiled only, not linked: no version of the library has been found,
+ * only the header files exist in the NDK.
+ */
+#include <cpu-features.h>
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   /* This is a whole lot easier than the linux code, however it is probably
+    * implemented as below, therefore it is better to cache the result (these
+    * function calls may be slow!)
+    */
+   PNG_UNUSED(png_ptr)
+   return android_getCpuFamily() == ANDROID_CPU_FAMILY_ARM &&
+      (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) != 0;
+}
diff --git a/extern/libpng/contrib/arm-neon/linux-auxv.c b/extern/libpng/contrib/arm-neon/linux-auxv.c
new file mode 100644
index 0000000000..4d26bd3b35
--- /dev/null
+++ b/extern/libpng/contrib/arm-neon/linux-auxv.c
@@ -0,0 +1,120 @@
+/* contrib/arm-neon/linux-auxv.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ * Last changed in libpng 1.6.10 [March 6, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: COMPILED, TESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for Linux versions which allow access to
+ * /proc/self/auxv.  This is probably faster, cleaner and safer than the code to
+ * read /proc/cpuinfo in contrib/arm-neon/linux, however it is yet another piece
+ * of potentially untested code and has more complex dependencies than the code
+ * to read cpuinfo.
+ *
+ * This generic __linux__ implementation requires reading /proc/self/auxv and
+ * looking at each element for one that records NEON capabilities.
+ */
+#include <unistd.h> /* for POSIX 1003.1 */
+#include <errno.h>  /* for EINTR */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <elf.h>
+#include <asm/hwcap.h>
+
+/* A read call may be interrupted, in which case it returns -1 and sets errno to
+ * EINTR if nothing was done, otherwise (if something was done) a partial read
+ * may result.
+ */
+static size_t
+safe_read(png_structp png_ptr, int fd, void *buffer_in, size_t nbytes)
+{
+   size_t ntotal = 0;
+   char *buffer = png_voidcast(char*, buffer_in);
+
+   while (nbytes > 0)
+   {
+      unsigned int nread;
+      int iread;
+
+      /* Passing nread > INT_MAX to read is implementation defined in POSIX
+       * 1003.1, therefore despite the unsigned argument portable code must
+       * limit the value to INT_MAX!
+       */
+      if (nbytes > INT_MAX)
+         nread = INT_MAX;
+
+      else
+         nread = (unsigned int)/*SAFE*/nbytes;
+
+      iread = read(fd, buffer, nread);
+
+      if (iread == -1)
+      {
+         /* This is the devil in the details, a read can terminate early with 0
+          * bytes read because of EINTR, yet it still returns -1 otherwise end
+          * of file cannot be distinguished.
+          */
+         if (errno != EINTR)
+         {
+            png_warning(png_ptr, "/proc read failed");
+            return 0; /* I.e., a permanent failure */
+         }
+      }
+
+      else if (iread < 0)
+      {
+         /* Not a valid 'read' result: */
+         png_warning(png_ptr, "OS /proc read bug");
+         return 0;
+      }
+
+      else if (iread > 0)
+      {
+         /* Continue reading until a permanent failure, or EOF */
+         buffer += iread;
+         nbytes -= (unsigned int)/*SAFE*/iread;
+         ntotal += (unsigned int)/*SAFE*/iread;
+      }
+
+      else
+         return ntotal;
+   }
+
+   return ntotal; /* nbytes == 0 */
+}
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   int fd = open("/proc/self/auxv", O_RDONLY);
+   Elf32_auxv_t aux;
+
+   /* Failsafe: failure to open means no NEON */
+   if (fd == -1)
+   {
+      png_warning(png_ptr, "/proc/self/auxv open failed");
+      return 0;
+   }
+
+   while (safe_read(png_ptr, fd, &aux, sizeof aux) == sizeof aux)
+   {
+      if (aux.a_type == AT_HWCAP && (aux.a_un.a_val & HWCAP_NEON) != 0)
+      {
+         close(fd);
+         return 1;
+      }
+   }
+
+   close(fd);
+   return 0;
+}
diff --git a/extern/libpng/contrib/arm-neon/linux.c b/extern/libpng/contrib/arm-neon/linux.c
new file mode 100644
index 0000000000..a9bc360dd5
--- /dev/null
+++ b/extern/libpng/contrib/arm-neon/linux.c
@@ -0,0 +1,161 @@
+/* contrib/arm-neon/linux.c
+ *
+ * Last changed in libpng 1.6.31 [July 27, 2017]
+ * Copyright (c) 2014, 2017 Glenn Randers-Pehrson
+ * Written by John Bowler, 2014, 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: SUPPORTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for Linux by reading the widely available
+ * pseudo-file /proc/cpuinfo.
+ *
+ * This code is strict ANSI-C and is probably moderately portable; it does
+ * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ */
+#include <stdio.h>
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   FILE *f = fopen("/proc/cpuinfo", "rb");
+
+   if (f != NULL)
+   {
+      /* This is a simple state machine which reads the input byte-by-byte until
+       * it gets a match on the 'neon' feature or reaches the end of the stream.
+       */
+      static const char ch_feature[] = { 70, 69, 65, 84, 85, 82, 69, 83 };
+      static const char ch_neon[] = { 78, 69, 79, 78 };
+
+      enum
+      {
+         StartLine, Feature, Colon, StartTag, Neon, HaveNeon, SkipTag, SkipLine
+      }  state;
+      int counter;
+
+      for (state=StartLine, counter=0;;)
+      {
+         int ch = fgetc(f);
+
+         if (ch == EOF)
+         {
+            /* EOF means error or end-of-file, return false; neon at EOF is
+             * assumed to be a mistake.
+             */
+            fclose(f);
+            return 0;
+         }
+
+         switch (state)
+         {
+            case StartLine:
+               /* Match spaces at the start of line */
+               if (ch <= 32) /* skip control characters and space */
+                  break;
+
+               counter=0;
+               state = Feature;
+               /* FALLTHROUGH */
+
+            case Feature:
+               /* Match 'FEATURE', ASCII case insensitive. */
+               if ((ch & ~0x20) == ch_feature[counter])
+               {
+                  if (++counter == (sizeof ch_feature))
+                     state = Colon;
+                  break;
+               }
+
+               /* did not match 'feature' */
+               state = SkipLine;
+               /* FALLTHROUGH */
+
+            case SkipLine:
+            skipLine:
+               /* Skip everything until we see linefeed or carriage return */
+               if (ch != 10 && ch != 13)
+                  break;
+
+               state = StartLine;
+               break;
+
+            case Colon:
+               /* Match any number of space or tab followed by ':' */
+               if (ch == 32 || ch == 9)
+                  break;
+
+               if (ch == 58) /* i.e. ':' */
+               {
+                  state = StartTag;
+                  break;
+               }
+
+               /* Either a bad line format or a 'feature' prefix followed by
+                * other characters.
+                */
+               state = SkipLine;
+               goto skipLine;
+
+            case StartTag:
+               /* Skip space characters before a tag */
+               if (ch == 32 || ch == 9)
+                  break;
+
+               state = Neon;
+               counter = 0;
+               /* FALLTHROUGH */
+
+            case Neon:
+               /* Look for 'neon' tag */
+               if ((ch & ~0x20) == ch_neon[counter])
+               {
+                  if (++counter == (sizeof ch_neon))
+                     state = HaveNeon;
+                  break;
+               }
+
+               state = SkipTag;
+               /* FALLTHROUGH */
+
+            case SkipTag:
+               /* Skip non-space characters */
+               if (ch == 10 || ch == 13)
+                  state = StartLine;
+
+               else if (ch == 32 || ch == 9)
+                  state = StartTag;
+               break;
+
+            case HaveNeon:
+               /* Have seen a 'neon' prefix, but there must be a space or new
+                * line character to terminate it.
+                */
+               if (ch == 10 || ch == 13 || ch == 32 || ch == 9)
+               {
+                  fclose(f);
+                  return 1;
+               }
+
+               state = SkipTag;
+               break;
+
+            default:
+               png_error(png_ptr, "png_have_neon: internal error (bug)");
+         }
+      }
+   }
+
+#ifdef PNG_WARNINGS_SUPPORTED
+   else
+      png_warning(png_ptr, "/proc/cpuinfo open failed");
+#endif
+
+   return 0;
+}
diff --git a/extern/libpng/contrib/conftest/README b/extern/libpng/contrib/conftest/README
new file mode 100644
index 0000000000..0f472791f2
--- /dev/null
+++ b/extern/libpng/contrib/conftest/README
@@ -0,0 +1,49 @@
+This directory contains test configuration files, currently always '.dfa' files
+intended to be used in the build by setting the make macro DFA_XTRA to the name
+of the file.
+
+These files are used in release validation of the 'configure' builds of libpng
+by building 'make check', or 'make all-am' for cross-builds, with each .dfa
+file.
+
+The files in this directory may change between minor releases, however
+contributions describing specific builds of libpng are welcomed.  There is no
+guarantee that libpng will continue to build with such configurations; support
+for given configurations can be, and has been, dropped between successive minor
+releases.  However if a .dfa file describing a configuration is not in this
+directory it is very unlikely that it will be tested before a minor release!
+
+You can use these .dfa files as the basis of new configurations.  Files in this
+directory should not have any use restrictions or restrictive licenses.
+
+This directory is not included in the .zip and .7z distributions, which do
+not contain 'configure' scripts.
+
+DOCUMENTATION
+=============
+
+Examples:
+   ${srcdir}/pngusr.dfa
+   ${srcdir}/contrib/pngminim/*/pngusr.dfa
+
+Documentation of the options:
+   ${srcdir}/scripts/pnglibconf.dfa
+
+Documentation of the file format:
+   ${srcdir}/scripts/options.awk
+
+FILE NAMING
+===========
+
+File names in this directory may NOT contain any of the five characters:
+
+   - , + * ?
+
+Neither may they contain any space character.
+
+While other characters may be used it is strongly suggested that file names be
+limited to lower case Latiin alphabetic characters (a-z), digits (0-9) and, if
+necessary the underscore (_) character.  File names should be about 8 characters
+long (excluding the .dfa extension).  Submitted .dfa files should have names
+between 7 and 16 characters long, shorter names (6 characters or less) are
+reserved for standard tests.
diff --git a/extern/libpng/contrib/conftest/pngcp.dfa b/extern/libpng/contrib/conftest/pngcp.dfa
new file mode 100644
index 0000000000..31c411d5f8
--- /dev/null
+++ b/extern/libpng/contrib/conftest/pngcp.dfa
@@ -0,0 +1,57 @@
+# pngcp.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2016
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with support for pngcp.  This means just png_read_png,
+# png_write_png and small number of configuration settings.
+#
+everything = off
+
+# This option is specific to this configuration; it adds a #define to the
+# generated pnglibconf.h which turns on the (not portable) timing option for
+# pngcp.  Note that any option is automatically preceded by PNG_; there is no
+# way round this and this is deliberate.
+option PNGCP_TIMING
+
+# Because of the everything off above the option must also be turned on.  This
+# may not be done in one step because it is safer and avoids mis-spelled options
+# in user .dfa files to error out if an unrecognized option is turned on.
+option PNGCP_TIMING on
+
+# Options to turn on png_read_png and png_write_png:
+option INFO_IMAGE on
+option SEQUENTIAL_READ on
+option EASY_ACCESS on
+option WRITE on
+option WRITE_16BIT on
+option WRITE_FILTER on
+
+# pngcp needs this to preserve unknown chunks, switching all these on means that
+# pngcp can work without explicit known chunk reading support
+option UNKNOWN_CHUNKS on
+option SET_UNKNOWN_CHUNKS on
+option HANDLE_AS_UNKNOWN on
+option SAVE_UNKNOWN_CHUNKS on
+option WRITE_UNKNOWN_CHUNKS on
+
+# pngcp needs this to handle palette files with invalid indices:
+option CHECK_FOR_INVALID_INDEX on
+option GET_PALETTE_MAX on
+
+# Pre-libpng 1.7 pngcp has to stash text chunks manually, post 1.7 without this
+# text chunks should be handled as unknown ok.
+option TEXT on
+
+# this is used to turn off limits:
+option USER_LIMITS on
+option SET_USER_LIMITS on
+
+# these are just required for specific customizations
+option WRITE_CUSTOMIZE_ZTXT_COMPRESSION on
+option WRITE_CUSTOMIZE_COMPRESSION on
diff --git a/extern/libpng/contrib/conftest/read.dfa b/extern/libpng/contrib/conftest/read.dfa
new file mode 100644
index 0000000000..21e88d01a2
--- /dev/null
+++ b/extern/libpng/contrib/conftest/read.dfa
@@ -0,0 +1,58 @@
+# read.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with basic read support.  This enables the lowest level libpng
+# read API - the one where the calling code has to use a loop to read each row.
+# At present this is the API used by most programs.
+#
+# Support is enabled only for those chunks and transformations that are
+# typically required - others can be added easily.
+#
+
+everything = off
+
+# The sequential read code is enabled here; the progressive code can be used
+# instead but there is no point enabling both.
+
+option SEQUENTIAL_READ on
+
+# Likewise it is pointless enabling both fixed and floating point APIs.  Choose
+# one or the other for both the API and the internal math.
+
+#Fixed point:
+#option FIXED_POINT on
+#option FLOATING_ARITHMETIC off
+
+#Floating point:
+option FLOATING_POINT on
+option FLOATING_ARITHMETIC on
+
+# Basic error handling, IO and user memory support.  The latter allows the
+# application program to provide its own implementations of 'malloc' and 'free'.
+option SETJMP on
+option STDIO on
+option USER_MEM on
+
+# To read the full set of PNG images correctly interlace, transparency and
+# 16-bit support is required.  The application can implement interlace itself,
+# but very few do and it's no longer possible to disable it when READ is
+# enabled.
+option READ_tRNS on
+option READ_16BIT on
+
+# Everything else is application dependent.  This file assumes the app handles
+# all the native PNG bit layouts, so it doesn't need any of layout change
+# transforms, but needs libpng to perform gamma correction.  It doesn't do any
+# colorspace stuff and ignores the 'significant bit' information.
+#
+# If your app always expands the image to a limited set of bit layouts you
+# probably want to consider using the simplified API instead of the low level
+# one - see png.h and s_read.dfa.
+option READ_GAMMA on
diff --git a/extern/libpng/contrib/conftest/s_read.dfa b/extern/libpng/contrib/conftest/s_read.dfa
new file mode 100644
index 0000000000..cb1ce0ba65
--- /dev/null
+++ b/extern/libpng/contrib/conftest/s_read.dfa
@@ -0,0 +1,35 @@
+# s_read.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with simplified read support (only).  This builds a minimal
+# libpng able to read all PNG formats and convert them into a small number of
+# well understood memory formats.
+#
+
+everything = off
+
+option SIMPLIFIED_READ on
+
+# It isn't necessary to chose fixed or floating point for the APIs because the
+# simplified API doesn't need fixed or floating point numbers.  It is necessary
+# to chose an internal math implementation.  The default (because of 'everything
+# = off') is fixed point - turn the floating point implementation on if you have
+# hardware floating point or prefer your software floating point implementation.
+option FLOATING_ARITHMETIC on
+
+# This is not strictly necessary, but without it the message strings in the API
+# will not be filled in
+option ERROR_TEXT on
+
+# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
+# need this if you don't use them, they just allow the in-memory layout to be
+# changed to match common hardware formats.
+option SIMPLIFIED_READ_AFIRST on
+option SIMPLIFIED_READ_BGR on
diff --git a/extern/libpng/contrib/conftest/s_write.dfa b/extern/libpng/contrib/conftest/s_write.dfa
new file mode 100644
index 0000000000..e540a46dc8
--- /dev/null
+++ b/extern/libpng/contrib/conftest/s_write.dfa
@@ -0,0 +1,33 @@
+# s_write.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with (just) simplified write support
+#
+
+everything = off
+
+option SIMPLIFIED_WRITE on
+
+# It isn't necessary to chose fixed or floating point for the APIs because the
+# simplified API doesn't need fixed or floating point numbers.  It is necessary
+# to chose an internal math implementation.  The default (because of 'everything
+# = off') is fixed point - turn the floating point implementation on if you have
+# hardware floating point or prefer your software floating point implementation.
+option FLOATING_ARITHMETIC on
+
+# This is not strictly necessary, but without it the message strings in the API
+# will not be filled in
+option ERROR_TEXT on
+
+# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
+# need this if you don't use them, they just allow the in-memory layout to be
+# changed to match common hardware formats.
+option SIMPLIFIED_WRITE_AFIRST on
+option SIMPLIFIED_WRITE_BGR on
diff --git a/extern/libpng/contrib/conftest/simple.dfa b/extern/libpng/contrib/conftest/simple.dfa
new file mode 100644
index 0000000000..0419333445
--- /dev/null
+++ b/extern/libpng/contrib/conftest/simple.dfa
@@ -0,0 +1,36 @@
+# simple.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with just the simplified APIs (read and write).
+#
+
+everything = off
+
+option SIMPLIFIED_WRITE on
+option SIMPLIFIED_READ on
+
+# It isn't necessary to chose fixed or floating point for the APIs because the
+# simplified API doesn't need fixed or floating point numbers.  It is necessary
+# to chose an internal math implementation.  The default (because of 'everything
+# = off') is fixed point - turn the floating point implementation on if you have
+# hardware floating point or prefer your software floating point implementation.
+option FLOATING_ARITHMETIC on
+
+# This is not strictly necessary, but without it the message strings in the API
+# will not be filled in
+option ERROR_TEXT on
+
+# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
+# need this if you don't use them, they just allow the in-memory layout to be
+# changed to match common hardware formats.
+option SIMPLIFIED_READ_AFIRST on
+option SIMPLIFIED_READ_BGR on
+option SIMPLIFIED_WRITE_AFIRST on
+option SIMPLIFIED_WRITE_BGR on
diff --git a/extern/libpng/contrib/conftest/write.dfa b/extern/libpng/contrib/conftest/write.dfa
new file mode 100644
index 0000000000..3319aabeeb
--- /dev/null
+++ b/extern/libpng/contrib/conftest/write.dfa
@@ -0,0 +1,45 @@
+# write.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with no read support and minimal write support.
+#
+
+everything = off
+
+# Switch on the write code - this makes a minimalist encoder
+
+option WRITE on
+
+# Choose fixed or floating point APIs and arithmetic.  The choices are
+# independent but normally they will match.  It is typically better to use the
+# floating point if you have floating point hardware.  If you don't know, or
+# (perhaps) to make libpng smaller used fixed point throughout.
+
+#Fixed point:
+#option FIXED_POINT on
+#option FLOATING_ARITHMETIC off
+
+#Floating point:
+option FLOATING_POINT on
+option FLOATING_ARITHMETIC on
+
+# Basic error handling, IO and user memory support.  The latter allows the
+# application program to provide its own implementations of 'malloc' and 'free'.
+option SETJMP on
+option STDIO on
+option USER_MEM on
+
+# Everything else is optional.  Unlike the read code in libpng the write code
+# does not need to deal with arbitrary formats, so only add support for things
+# you really do write!  For example you might only write sRGB images, sometimes
+# with transparency and never write 16 bit images, so:
+option WRITE_sRGB on
+option WRITE_tRNS on
+#option WRITE_16BIT off (this is the default with 'everything = off')
diff --git a/extern/libpng/contrib/examples/README.txt b/extern/libpng/contrib/examples/README.txt
new file mode 100644
index 0000000000..48dab4f0fd
--- /dev/null
+++ b/extern/libpng/contrib/examples/README.txt
@@ -0,0 +1,24 @@
+
+This directory (contrib/examples) contains examples of libpng usage.
+
+NO COPYRIGHT RIGHTS ARE CLAIMED TO ANY OF THE FILES IN THIS DIRECTORY.
+
+To the extent possible under law, the authors have waived all copyright and
+related or neighboring rights to this work.  This work is published from:
+United States.
+
+The files may be used freely in any way.  The intention is that appropriate
+parts of the files be used in other libpng-using programs without any need for
+the authors of the using code to seek copyright or license from the original
+authors.
+
+The source code and comments in this directory are the original work of the
+people named below.  No other person or organization has made contributions to
+the work in this directory.
+
+ORIGINAL AUTHORS
+    The following people have contributed to the code in this directory.  None
+    of the people below claim any rights with regard to the contents of this
+    directory.
+
+    John Bowler <jbowler at acm.org>
diff --git a/extern/libpng/contrib/examples/iccfrompng.c b/extern/libpng/contrib/examples/iccfrompng.c
new file mode 100644
index 0000000000..00056abfd7
--- /dev/null
+++ b/extern/libpng/contrib/examples/iccfrompng.c
@@ -0,0 +1,185 @@
+/*- iccfrompng
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Extract any icc profiles found in the given PNG files.  This is a simple
+ * example of a program that extracts information from the header of a PNG file
+ * without processing the image.  Notice that some header information may occur
+ * after the image data. Textual data and comments are an example; the approach
+ * in this file won't work reliably for such data because it only looks for the
+ * information in the section of the file that precedes the image data.
+ *
+ * Compile and link against libpng and zlib, plus anything else required on the
+ * system you use.
+ *
+ * To use supply a list of PNG files containing iCCP chunks, the chunks will be
+ * extracted to a similarly named file with the extension replaced by 'icc',
+ * which will be overwritten without warning.
+ */
+#include <stdlib.h>
+#include <setjmp.h>
+#include <string.h>
+#include <stdio.h>
+
+#include <png.h>
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \
+    defined (PNG_iCCP_SUPPORTED)
+
+
+static int verbose = 1;
+static png_byte no_profile[] = "no profile";
+
+static png_bytep
+extract(FILE *fp, png_uint_32 *proflen)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
+   png_infop info_ptr = NULL;
+   png_bytep result = NULL;
+
+   /* Initialize for error or no profile: */
+   *proflen = 0;
+
+   if (png_ptr == NULL)
+   {
+      fprintf(stderr, "iccfrompng: version library mismatch?\n");
+      return 0;
+   }
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      return 0;
+   }
+
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   png_read_info(png_ptr, info_ptr);
+
+   {
+      png_charp name;
+      int compression_type;
+      png_bytep profile;
+
+      if (png_get_iCCP(png_ptr, info_ptr, &name, &compression_type, &profile,
+         proflen) & PNG_INFO_iCCP)
+      {
+         result = malloc(*proflen);
+         if (result != NULL)
+            memcpy(result, profile, *proflen);
+
+         else
+            png_error(png_ptr, "OOM allocating profile buffer");
+      }
+
+      else
+	result = no_profile;
+   }
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   return result;
+}
+
+static int
+extract_one_file(const char *filename)
+{
+   int result = 0;
+   FILE *fp = fopen(filename, "rb");
+
+   if (fp != NULL)
+   {
+      png_uint_32 proflen = 0;
+      png_bytep profile = extract(fp, &proflen);
+
+      if (profile != NULL && profile != no_profile)
+      {
+         size_t len;
+         char *output;
+
+         {
+            const char *ep = strrchr(filename, '.');
+
+            if (ep != NULL)
+               len = ep-filename;
+
+            else
+               len = strlen(filename);
+         }
+
+         output = malloc(len + 5);
+         if (output != NULL)
+         {
+            FILE *of;
+
+            memcpy(output, filename, len);
+            strcpy(output+len, ".icc");
+
+            of = fopen(output, "wb");
+            if (of != NULL)
+            {
+               if (fwrite(profile, proflen, 1, of) == 1 &&
+                  fflush(of) == 0 &&
+                  fclose(of) == 0)
+               {
+                  if (verbose)
+                     printf("%s -> %s\n", filename, output);
+                  /* Success return */
+                  result = 1;
+               }
+
+               else
+               {
+                  fprintf(stderr, "%s: error writing profile\n", output);
+                  if (remove(output))
+                     fprintf(stderr, "%s: could not remove file\n", output);
+               }
+            }
+
+            else
+               fprintf(stderr, "%s: failed to open output file\n", output);
+
+            free(output);
+         }
+
+         else
+            fprintf(stderr, "%s: OOM allocating string!\n", filename);
+
+         free(profile);
+      }
+
+      else if (verbose && profile == no_profile)
+	printf("%s has no profile\n", filename);
+   }
+
+   else
+      fprintf(stderr, "%s: could not open file\n", filename);
+
+   return result;
+}
+
+int
+main(int argc, char **argv)
+{
+   int i;
+   int extracted = 0;
+
+   for (i=1; i<argc; ++i)
+   {
+      if (strcmp(argv[i], "-q") == 0)
+         verbose = 0;
+
+      else if (extract_one_file(argv[i]))
+         extracted = 1;
+   }
+
+   /* Exit code is true if any extract succeeds */
+   return extracted == 0;
+}
+#endif /* READ && STDIO && iCCP */
diff --git a/extern/libpng/contrib/examples/pngpixel.c b/extern/libpng/contrib/examples/pngpixel.c
new file mode 100644
index 0000000000..9185d518fb
--- /dev/null
+++ b/extern/libpng/contrib/examples/pngpixel.c
@@ -0,0 +1,371 @@
+/*- pngpixel
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Read a single pixel value from a PNG file.
+ *
+ * This code illustrates basic 'by-row' reading of a PNG file using libpng.
+ * Rows are read until a particular pixel is found; the value of this pixel is
+ * then printed on stdout.
+ *
+ * The code illustrates how to do this on interlaced as well as non-interlaced
+ * images.  Normally you would call png_set_interlace_handling() to have libpng
+ * deal with the interlace for you, but that obliges you to buffer half of the
+ * image to assemble the interlaced rows.  In this code
+ * png_set_interlace_handling() is not called and, instead, the code handles the
+ * interlace passes directly looking for the required pixel.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <setjmp.h> /* required for error handling */
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation:
+ */
+#include "../../png.h"
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+
+/* Return component 'c' of pixel 'x' from the given row. */
+static unsigned int
+component(png_const_bytep row, png_uint_32 x, unsigned int c,
+   unsigned int bit_depth, unsigned int channels)
+{
+   /* PNG images can be up to 2^31 pixels wide, but this means they can be up to
+    * 2^37 bits wide (for a 64-bit pixel - the largest possible) and hence 2^34
+    * bytes wide.  Since the row fitted into memory, however, the following must
+    * work:
+    */
+   png_uint_32 bit_offset_hi = bit_depth * ((x >> 6) * channels);
+   png_uint_32 bit_offset_lo = bit_depth * ((x & 0x3f) * channels + c);
+
+   row = (png_const_bytep)(((const png_byte (*)[8])row) + bit_offset_hi);
+   row += bit_offset_lo >> 3;
+   bit_offset_lo &= 0x07;
+
+   /* PNG pixels are packed into bytes to put the first pixel in the highest
+    * bits of the byte and into two bytes for 16-bit values with the high 8 bits
+    * first, so:
+    */
+   switch (bit_depth)
+   {
+      case 1: return (row[0] >> (7-bit_offset_lo)) & 0x01;
+      case 2: return (row[0] >> (6-bit_offset_lo)) & 0x03;
+      case 4: return (row[0] >> (4-bit_offset_lo)) & 0x0f;
+      case 8: return row[0];
+      case 16: return (row[0] << 8) + row[1];
+      default:
+         /* This should never happen; it indicates a bug in this program or in
+          * libpng itself:
+          */
+         fprintf(stderr, "pngpixel: invalid bit depth %u\n", bit_depth);
+         exit(1);
+   }
+}
+
+/* Print a pixel from a row returned by libpng; determine the row format, find
+ * the pixel, and print the relevant information to stdout.
+ */
+static void
+print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
+   png_uint_32 x)
+{
+   unsigned int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
+
+   switch (png_get_color_type(png_ptr, info_ptr))
+   {
+      case PNG_COLOR_TYPE_GRAY:
+         printf("GRAY %u\n", component(row, x, 0, bit_depth, 1));
+         return;
+
+      /* The palette case is slightly more difficult - the palette and, if
+       * present, the tRNS ('transparency', though the values are really
+       * opacity) data must be read to give the full picture:
+       */
+      case PNG_COLOR_TYPE_PALETTE:
+         {
+            int index = component(row, x, 0, bit_depth, 1);
+            png_colorp palette = NULL;
+            int num_palette = 0;
+
+            if ((png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) &
+               PNG_INFO_PLTE) && num_palette > 0 && palette != NULL)
+            {
+               png_bytep trans_alpha = NULL;
+               int num_trans = 0;
+               if ((png_get_tRNS(png_ptr, info_ptr, &trans_alpha, &num_trans,
+                  NULL) & PNG_INFO_tRNS) && num_trans > 0 &&
+                  trans_alpha != NULL)
+                  printf("INDEXED %u = %d %d %d %d\n", index,
+                     palette[index].red, palette[index].green,
+                     palette[index].blue,
+                     index < num_trans ? trans_alpha[index] : 255);
+
+               else /* no transparency */
+                  printf("INDEXED %u = %d %d %d\n", index,
+                     palette[index].red, palette[index].green,
+                     palette[index].blue);
+            }
+
+            else
+               printf("INDEXED %u = invalid index\n", index);
+         }
+         return;
+
+      case PNG_COLOR_TYPE_RGB:
+         printf("RGB %u %u %u\n", component(row, x, 0, bit_depth, 3),
+            component(row, x, 1, bit_depth, 3),
+            component(row, x, 2, bit_depth, 3));
+         return;
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         printf("GRAY+ALPHA %u %u\n", component(row, x, 0, bit_depth, 2),
+            component(row, x, 1, bit_depth, 2));
+         return;
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         printf("RGBA %u %u %u %u\n", component(row, x, 0, bit_depth, 4),
+            component(row, x, 1, bit_depth, 4),
+            component(row, x, 2, bit_depth, 4),
+            component(row, x, 3, bit_depth, 4));
+         return;
+
+      default:
+         png_error(png_ptr, "pngpixel: invalid color type");
+   }
+}
+
+int main(int argc, const char **argv)
+{
+   /* This program uses the default, <setjmp.h> based, libpng error handling
+    * mechanism, therefore any local variable that exists before the call to
+    * setjmp and is changed after the call to setjmp returns successfully must
+    * be declared with 'volatile' to ensure that their values don't get
+    * destroyed by longjmp:
+    */
+   volatile int result = 1/*fail*/;
+
+   if (argc == 4)
+   {
+      long x = atol(argv[1]);
+      long y = atol(argv[2]);
+      FILE *f = fopen(argv[3], "rb");
+      volatile png_bytep row = NULL;
+
+      if (f != NULL)
+      {
+         /* libpng requires a callback function for handling errors; this
+          * callback must not return.  The default callback function uses a
+          * stored <setjmp.h> style jmp_buf which is held in a png_struct and
+          * writes error messages to stderr.  Creating the png_struct is a
+          * little tricky; just copy the following code.
+          */
+         png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+            NULL, NULL, NULL);
+
+         if (png_ptr != NULL)
+         {
+            png_infop info_ptr = png_create_info_struct(png_ptr);
+
+            if (info_ptr != NULL)
+            {
+               /* Declare stack variables to hold pointers to locally allocated
+                * data.
+                */
+
+               /* Initialize the error control buffer: */
+               if (setjmp(png_jmpbuf(png_ptr)) == 0)
+               {
+                  png_uint_32 width, height;
+                  int bit_depth, color_type, interlace_method,
+                     compression_method, filter_method;
+                  png_bytep row_tmp;
+
+                  /* Now associate the recently opened (FILE*) with the default
+                   * libpng initialization functions.  Sometimes libpng is
+                   * compiled without stdio support (it can be difficult to do
+                   * in some environments); in that case you will have to write
+                   * your own read callback to read data from the (FILE*).
+                   */
+                  png_init_io(png_ptr, f);
+
+                  /* And read the first part of the PNG file - the header and
+                   * all the information up to the first pixel.
+                   */
+                  png_read_info(png_ptr, info_ptr);
+
+                  /* This fills in enough information to tell us the width of
+                   * each row in bytes, allocate the appropriate amount of
+                   * space.  In this case png_malloc is used - it will not
+                   * return if memory isn't available.
+                   */
+                  row = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
+                     info_ptr));
+
+                  /* To avoid the overhead of using a volatile auto copy row_tmp
+                   * to a local here - just use row for the png_free below.
+                   */
+                  row_tmp = row;
+
+                  /* All the information we need is in the header is returned by
+                   * png_get_IHDR, if this fails we can now use 'png_error' to
+                   * signal the error and return control to the setjmp above.
+                   */
+                  if (png_get_IHDR(png_ptr, info_ptr, &width, &height,
+                     &bit_depth, &color_type, &interlace_method,
+                     &compression_method, &filter_method))
+                  {
+                     int passes, pass;
+
+                     /* png_set_interlace_handling returns the number of
+                      * passes required as well as turning on libpng's
+                      * handling, but since we do it ourselves this is
+                      * necessary:
+                      */
+                     switch (interlace_method)
+                     {
+                        case PNG_INTERLACE_NONE:
+                           passes = 1;
+                           break;
+
+                        case PNG_INTERLACE_ADAM7:
+                           passes = PNG_INTERLACE_ADAM7_PASSES;
+                           break;
+
+                        default:
+                           png_error(png_ptr, "pngpixel: unknown interlace");
+                     }
+
+                     /* Now read the pixels, pass-by-pass, row-by-row: */
+                     png_start_read_image(png_ptr);
+
+                     for (pass=0; pass<passes; ++pass)
+                     {
+                        png_uint_32 ystart, xstart, ystep, xstep;
+                        png_uint_32 py;
+
+                        if (interlace_method == PNG_INTERLACE_ADAM7)
+                        {
+                           /* Sometimes the whole pass is empty because the
+                            * image is too narrow or too short.  libpng
+                            * expects to be called for each row that is
+                            * present in the pass, so it may be necessary to
+                            * skip the loop below (over py) if the image is
+                            * too narrow.
+                            */
+                           if (PNG_PASS_COLS(width, pass) == 0)
+                              continue;
+
+                           /* We need the starting pixel and the offset
+                            * between each pixel in this pass; use the macros
+                            * in png.h:
+                            */
+                           xstart = PNG_PASS_START_COL(pass);
+                           ystart = PNG_PASS_START_ROW(pass);
+                           xstep = PNG_PASS_COL_OFFSET(pass);
+                           ystep = PNG_PASS_ROW_OFFSET(pass);
+                        }
+
+                        else
+                        {
+                           ystart = xstart = 0;
+                           ystep = xstep = 1;
+                        }
+
+                        /* To find the pixel, loop over 'py' for each pass
+                         * reading a row and then checking to see if it
+                         * contains the pixel.
+                         */
+                        for (py = ystart; py < height; py += ystep)
+                        {
+                           png_uint_32 px, ppx;
+
+                           /* png_read_row takes two pointers.  When libpng
+                            * handles the interlace the first is filled in
+                            * pixel-by-pixel, and the second receives the same
+                            * pixels but they are replicated across the
+                            * unwritten pixels so far for each pass.  When we
+                            * do the interlace, however, they just contain
+                            * the pixels from the interlace pass - giving
+                            * both is wasteful and pointless, so we pass a
+                            * NULL pointer.
+                            */
+                           png_read_row(png_ptr, row_tmp, NULL);
+
+                           /* Now find the pixel if it is in this row; there
+                            * are, of course, much better ways of doing this
+                            * than using a for loop:
+                            */
+                           if (y == py) for (px = xstart, ppx = 0;
+                              px < width; px += xstep, ++ppx) if (x == px)
+                           {
+                              /* 'ppx' is the index of the pixel in the row
+                               * buffer.
+                               */
+                              print_pixel(png_ptr, info_ptr, row_tmp, ppx);
+
+                              /* Now terminate the loops early - we have
+                               * found and handled the required data.
+                               */
+                              goto pass_loop_end;
+                           } /* x loop */
+                        } /* y loop */
+                     } /* pass loop */
+
+                     /* Finally free the temporary buffer: */
+                  pass_loop_end:
+                     row = NULL;
+                     png_free(png_ptr, row_tmp);
+                  }
+
+                  else
+                     png_error(png_ptr, "pngpixel: png_get_IHDR failed");
+
+               }
+
+               else
+               {
+                  /* Else libpng has raised an error.  An error message has
+                   * already been output, so it is only necessary to clean up
+                   * locally allocated data:
+                   */
+                  if (row != NULL)
+                  {
+                     /* The default implementation of png_free never errors out
+                      * (it just crashes if something goes wrong), but the safe
+                      * way of using it is still to clear 'row' before calling
+                      * png_free:
+                      */
+                     png_bytep row_tmp = row;
+                     row = NULL;
+                     png_free(png_ptr, row_tmp);
+                  }
+               }
+
+               png_destroy_info_struct(png_ptr, &info_ptr);
+            }
+
+            else
+               fprintf(stderr, "pngpixel: out of memory allocating png_info\n");
+
+            png_destroy_read_struct(&png_ptr, NULL, NULL);
+         }
+
+         else
+            fprintf(stderr, "pngpixel: out of memory allocating png_struct\n");
+      }
+
+      else
+         fprintf(stderr, "pngpixel: %s: could not open file\n", argv[3]);
+   }
+
+   else
+      /* Wrong number of arguments */
+      fprintf(stderr, "pngpixel: usage: pngpixel x y png-file\n");
+
+   return result;
+}
+#endif /* READ && SEQUENTIAL_READ */
diff --git a/extern/libpng/contrib/examples/pngtopng.c b/extern/libpng/contrib/examples/pngtopng.c
new file mode 100644
index 0000000000..904b972382
--- /dev/null
+++ b/extern/libpng/contrib/examples/pngtopng.c
@@ -0,0 +1,98 @@
+/*- pngtopng
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011, 2017.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Last changed in libpng 1.6.29 [March 16, 2017]
+ *
+ * Read a PNG and write it out in a fixed format, using the 'simplified API'
+ * that was introduced in libpng-1.6.0.
+ *
+ * This sample code is just the code from the top of 'example.c' with some error
+ * handling added.  See example.c for more comments.
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation:
+ */
+#include "../../png.h"
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && \
+    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+
+int main(int argc, const char **argv)
+{
+   int result = 1;
+
+   if (argc == 3)
+   {
+      png_image image;
+
+      /* Only the image structure version number needs to be set. */
+      memset(&image, 0, sizeof image);
+      image.version = PNG_IMAGE_VERSION;
+
+      if (png_image_begin_read_from_file(&image, argv[1]))
+      {
+         png_bytep buffer;
+
+         /* Change this to try different formats!  If you set a colormap format
+          * then you must also supply a colormap below.
+          */
+         image.format = PNG_FORMAT_RGBA;
+
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         if (buffer != NULL)
+         {
+            if (png_image_finish_read(&image, NULL/*background*/, buffer,
+               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
+            {
+               if (png_image_write_to_file(&image, argv[2],
+                  0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                  NULL/*colormap*/))
+                  result = 0;
+
+               else
+                  fprintf(stderr, "pngtopng: write %s: %s\n", argv[2],
+                      image.message);
+            }
+
+            else
+               fprintf(stderr, "pngtopng: read %s: %s\n", argv[1],
+                   image.message);
+
+            free(buffer);
+         }
+
+         else
+         {
+            fprintf(stderr, "pngtopng: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+
+            /* This is the only place where a 'free' is required; libpng does
+             * the cleanup on error and success, but in this case we couldn't
+             * complete the read because of running out of memory and so libpng
+             * has not got to the point where it can do cleanup.
+             */
+            png_image_free(&image);
+         }
+      }
+
+      else
+         /* Failed to read the first argument: */
+         fprintf(stderr, "pngtopng: %s: %s\n", argv[1], image.message);
+   }
+
+   else
+      /* Wrong number of arguments */
+      fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n");
+
+   return result;
+}
+#endif /* READ && WRITE */
diff --git a/extern/libpng/contrib/examples/simpleover.c b/extern/libpng/contrib/examples/simpleover.c
new file mode 100644
index 0000000000..59dd313688
--- /dev/null
+++ b/extern/libpng/contrib/examples/simpleover.c
@@ -0,0 +1,648 @@
+/*- simpleover
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2015.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Read several PNG files, which should have an alpha channel or transparency
+ * information, and composite them together to produce one or more 16-bit linear
+ * RGBA intermediates.  This involves doing the correct 'over' composition to
+ * combine the alpha channels and corresponding data.
+ *
+ * Finally read an output (background) PNG using the 24-bit RGB format (the
+ * PNG will be composited on green (#00ff00) by default if it has an alpha
+ * channel), and apply the intermediate image generated above to specified
+ * locations in the image.
+ *
+ * The command line has the general format:
+ *
+ *    simpleover <background.png> [output.png]
+ *        {--sprite=width,height,name {[--at=x,y] {sprite.png}}}
+ *        {--add=name {x,y}}
+ *
+ * The --sprite and --add options may occur multiple times. They are executed
+ * in order.  --add may refer to any sprite already read.
+ *
+ * This code is intended to show how to composite multiple images together
+ * correctly.  Apart from the libpng Simplified API the only work done in here
+ * is to combine multiple input PNG images into a single sprite; this involves
+ * a Porter-Duff 'over' operation and the input PNG images may, as a result,
+ * be regarded as being layered one on top of the other with the first (leftmost
+ * on the command line) being at the bottom and the last on the top.
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation, so long as this
+ * file is linked against a sufficiently recent libpng (1.6+) it is ok to
+ * change this to <png.h>:
+ */
+#include "../../png.h"
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+
+#define sprite_name_chars 15
+struct sprite {
+   FILE         *file;
+   png_uint_16p  buffer;
+   unsigned int  width;
+   unsigned int  height;
+   char          name[sprite_name_chars+1];
+};
+
+#if 0 /* div by 65535 test program */
+#include <math.h>
+#include <stdio.h>
+
+int main(void) {
+   double err = 0;
+   unsigned int xerr = 0;
+   unsigned int r = 32769;
+   {
+      unsigned int x = 0;
+
+      do {
+         unsigned int t = x + (x >> 16) /*+ (x >> 31)*/ + r;
+         double v = x, errtest;
+
+         if (t < x) {
+            fprintf(stderr, "overflow: %u+%u -> %u\n", x, r, t);
+            return 1;
+         }
+
+         v /= 65535;
+         errtest = v;
+         t >>= 16;
+         errtest -= t;
+
+         if (errtest > err) {
+            err = errtest;
+            xerr = x;
+
+            if (errtest >= .5) {
+               fprintf(stderr, "error: %u/65535 = %f, not %u, error %f\n",
+                     x, v, t, errtest);
+               return 0;
+            }
+         }
+      } while (++x <= 65535U*65535U);
+   }
+
+   printf("error %f @ %u\n", err, xerr);
+
+   return 0;
+}
+#endif /* div by 65535 test program */
+
+static void
+sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
+   png_imagep image, const png_uint_16 *buffer)
+{
+   /* This is where the Porter-Duff 'Over' operator is evaluated; change this
+    * code to change the operator (this could be parameterized).  Any other
+    * image processing operation could be used here.
+    */
+
+
+   /* Check for an x or y offset that pushes any part of the image beyond the
+    * right or bottom of the sprite:
+    */
+   if ((y_offset < 0 || (unsigned)/*SAFE*/y_offset < sprite->height) &&
+       (x_offset < 0 || (unsigned)/*SAFE*/x_offset < sprite->width))
+   {
+      unsigned int y = 0;
+
+      if (y_offset < 0)
+         y = -y_offset; /* Skip to first visible row */
+
+      do
+      {
+         unsigned int x = 0;
+
+         if (x_offset < 0)
+            x = -x_offset;
+
+         do
+         {
+            /* In and out are RGBA values, so: */
+            const png_uint_16 *in_pixel = buffer + (y * image->width + x)*4;
+            png_uint_32 in_alpha = in_pixel[3];
+
+            /* This is the optimized Porter-Duff 'Over' operation, when the
+             * input alpha is 0 the output is not changed.
+             */
+            if (in_alpha > 0)
+            {
+               png_uint_16 *out_pixel = sprite->buffer +
+                  ((y+y_offset) * sprite->width + (x+x_offset))*4;
+
+               /* This is the weight to apply to the output: */
+               in_alpha = 65535-in_alpha;
+
+               if (in_alpha > 0)
+               {
+                  /* The input must be composed onto the output. This means
+                   * multiplying the current output pixel value by the inverse
+                   * of the input alpha (1-alpha). A division is required but
+                   * it is by the constant 65535.  Approximate this as:
+                   *
+                   *     (x + (x >> 16) + 32769) >> 16;
+                   *
+                   * This is exact (and does not overflow) for all values of
+                   * x in the range 0..65535*65535.  (Note that the calculation
+                   * produces the closest integer; the maximum error is <0.5).
+                   */
+                  png_uint_32 tmp;
+
+#                 define compose(c)\
+                     tmp = out_pixel[c] * in_alpha;\
+                     tmp = (tmp + (tmp >> 16) + 32769) >> 16;\
+                     out_pixel[c] = tmp + in_pixel[c]
+
+                  /* The following is very vectorizable... */
+                  compose(0);
+                  compose(1);
+                  compose(2);
+                  compose(3);
+               }
+
+               else
+                  out_pixel[0] = in_pixel[0],
+                  out_pixel[1] = in_pixel[1],
+                  out_pixel[2] = in_pixel[2],
+                  out_pixel[3] = in_pixel[3];
+            }
+         }
+         while (++x < image->width);
+      }
+      while (++y < image->height);
+   }
+}
+
+static int
+create_sprite(struct sprite *sprite, int *argc, const char ***argv)
+{
+   /* Read the arguments and create this sprite. The sprite buffer has already
+    * been allocated. This reads the input PNGs one by one in linear format,
+    * composes them onto the sprite buffer (the code in the function above)
+    * then saves the result, converting it on the fly to PNG RGBA 8-bit format.
+    */
+   while (*argc > 0)
+   {
+      char tombstone;
+      int x = 0, y = 0;
+
+      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
+      {
+         /* The only supported option is --at. */
+         if (sscanf((*argv)[0], "--at=%d,%d%c", &x, &y, &tombstone) != 2)
+            break; /* success; caller will parse this option */
+
+         ++*argv, --*argc;
+      }
+
+      else
+      {
+         /* The argument has to be a file name */
+         png_image image;
+
+         image.version = PNG_IMAGE_VERSION;
+         image.opaque = NULL;
+
+         if (png_image_begin_read_from_file(&image, (*argv)[0]))
+         {
+            png_uint_16p buffer;
+
+            image.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+
+            buffer = malloc(PNG_IMAGE_SIZE(image));
+
+            if (buffer != NULL)
+            {
+               if (png_image_finish_read(&image, NULL/*background*/, buffer,
+                  0/*row_stride*/,
+                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+               {
+                  /* This is the place where the Porter-Duff 'Over' operator
+                   * needs to be done by this code.  In fact, any image
+                   * processing required can be done here; the data is in
+                   * the correct format (linear, 16-bit) and source and
+                   * destination are in memory.
+                   */
+                  sprite_op(sprite, x, y, &image, buffer);
+                  free(buffer);
+                  ++*argv, --*argc;
+                  /* And continue to the next argument */
+                  continue;
+               }
+
+               else
+               {
+                  free(buffer);
+                  fprintf(stderr, "simpleover: read %s: %s\n", (*argv)[0],
+                      image.message);
+               }
+            }
+
+            else
+            {
+               fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
+                  (unsigned long)PNG_IMAGE_SIZE(image));
+
+               /* png_image_free must be called if we abort the Simplified API
+                * read because of a problem detected in this code.  If problems
+                * are detected in the Simplified API it cleans up itself.
+                */
+               png_image_free(&image);
+            }
+         }
+
+         else
+         {
+            /* Failed to read the first argument: */
+            fprintf(stderr, "simpleover: %s: %s\n", (*argv)[0], image.message);
+         }
+
+         return 0; /* failure */
+      }
+   }
+
+   /* All the sprite operations have completed successfully. Save the RGBA
+    * buffer as a PNG using the simplified write API.
+    */
+   sprite->file = tmpfile();
+
+   if (sprite->file != NULL)
+   {
+      png_image save;
+
+      memset(&save, 0, sizeof save);
+      save.version = PNG_IMAGE_VERSION;
+      save.opaque = NULL;
+      save.width = sprite->width;
+      save.height = sprite->height;
+      save.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+      save.flags = PNG_IMAGE_FLAG_FAST;
+      save.colormap_entries = 0;
+
+      if (png_image_write_to_stdio(&save, sprite->file, 1/*convert_to_8_bit*/,
+          sprite->buffer, 0/*row_stride*/, NULL/*colormap*/))
+      {
+         /* Success; the buffer is no longer needed: */
+         free(sprite->buffer);
+         sprite->buffer = NULL;
+         return 1; /* ok */
+      }
+
+      else
+         fprintf(stderr, "simpleover: write sprite %s: %s\n", sprite->name,
+            save.message);
+   }
+
+   else
+      fprintf(stderr, "simpleover: sprite %s: could not allocate tmpfile: %s\n",
+         sprite->name, strerror(errno));
+
+   return 0; /* fail */
+}
+
+static int
+add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
+   int *argc, const char ***argv)
+{
+   /* Given a --add argument naming this sprite, perform the operations listed
+    * in the following arguments.  The arguments are expected to have the form
+    * (x,y), which is just an offset at which to add the sprite to the
+    * output.
+    */
+   while (*argc > 0)
+   {
+      char tombstone;
+      int x, y;
+
+      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
+         return 1; /* success */
+
+      if (sscanf((*argv)[0], "%d,%d%c", &x, &y, &tombstone) == 2)
+      {
+         /* Now add the new image into the sprite data, but only if it
+          * will fit.
+          */
+         if (x < 0 || y < 0 ||
+             (unsigned)/*SAFE*/x >= output->width ||
+             (unsigned)/*SAFE*/y >= output->height ||
+             sprite->width > output->width-x ||
+             sprite->height > output->height-y)
+         {
+            fprintf(stderr, "simpleover: sprite %s @ (%d,%d) outside image\n",
+               sprite->name, x, y);
+            /* Could just skip this, but for the moment it is an error */
+            return 0; /* error */
+         }
+
+         else
+         {
+            /* Since we know the sprite fits we can just read it into the
+             * output using the simplified API.
+             */
+            png_image in;
+
+            in.version = PNG_IMAGE_VERSION;
+            rewind(sprite->file);
+
+            if (png_image_begin_read_from_stdio(&in, sprite->file))
+            {
+               in.format = PNG_FORMAT_RGB; /* force compose */
+
+               if (png_image_finish_read(&in, NULL/*background*/,
+                  out_buf + (y*output->width + x)*3/*RGB*/,
+                  output->width*3/*row_stride*/,
+                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+               {
+                  ++*argv, --*argc;
+                  continue;
+               }
+            }
+
+            /* The read failed: */
+            fprintf(stderr, "simpleover: add sprite %s: %s\n", sprite->name,
+                in.message);
+            return 0; /* error */
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "simpleover: --add='%s': invalid position %s\n",
+               sprite->name, (*argv)[0]);
+         return 0; /* error */
+      }
+   }
+
+   return 1; /* ok */
+}
+
+static int
+simpleover_process(png_imagep output, png_bytep out_buf, int argc,
+   const char **argv)
+{
+   int result = 1; /* success */
+#  define csprites 10/*limit*/
+#  define str(a) #a
+   int nsprites = 0;
+   struct sprite sprites[csprites];
+
+   while (argc > 0)
+   {
+      result = 0; /* fail */
+
+      if (strncmp(argv[0], "--sprite=", 9) == 0)
+      {
+         char tombstone;
+
+         if (nsprites < csprites)
+         {
+            int n;
+
+            sprites[nsprites].width = sprites[nsprites].height = 0;
+            sprites[nsprites].name[0] = 0;
+
+            n = sscanf(argv[0], "--sprite=%u,%u,%" str(sprite_name_chars) "s%c",
+                &sprites[nsprites].width, &sprites[nsprites].height,
+                sprites[nsprites].name, &tombstone);
+
+            if ((n == 2 || n == 3) &&
+                sprites[nsprites].width > 0 && sprites[nsprites].height > 0)
+            {
+               size_t buf_size, tmp;
+
+               /* Default a name if not given. */
+               if (sprites[nsprites].name[0] == 0)
+                  sprintf(sprites[nsprites].name, "sprite-%d", nsprites+1);
+
+               /* Allocate a buffer for the sprite and calculate the buffer
+                * size:
+                */
+               buf_size = sizeof (png_uint_16 [4]);
+               buf_size *= sprites[nsprites].width;
+               buf_size *= sprites[nsprites].height;
+
+               /* This can overflow a (size_t); check for this: */
+               tmp = buf_size;
+               tmp /= sprites[nsprites].width;
+               tmp /= sprites[nsprites].height;
+
+               if (tmp == sizeof (png_uint_16 [4]))
+               {
+                  sprites[nsprites].buffer = malloc(buf_size);
+                  /* This buffer must be initialized to transparent: */
+                  memset(sprites[nsprites].buffer, 0, buf_size);
+
+                  if (sprites[nsprites].buffer != NULL)
+                  {
+                     sprites[nsprites].file = NULL;
+                     ++argv, --argc;
+
+                     if (create_sprite(sprites+nsprites++, &argc, &argv))
+                     {
+                        result = 1; /* still ok */
+                        continue;
+                     }
+
+                     break; /* error */
+                  }
+               }
+
+               /* Overflow, or OOM */
+               fprintf(stderr, "simpleover: %s: sprite too large\n", argv[0]);
+               break;
+            }
+
+            else
+            {
+               fprintf(stderr, "simpleover: %s: invalid sprite (%u,%u)\n",
+                  argv[0], sprites[nsprites].width, sprites[nsprites].height);
+               break;
+            }
+         }
+
+         else
+         {
+            fprintf(stderr, "simpleover: %s: too many sprites\n", argv[0]);
+            break;
+         }
+      }
+
+      else if (strncmp(argv[0], "--add=", 6) == 0)
+      {
+         const char *name = argv[0]+6;
+         int isprite = nsprites;
+
+         ++argv, --argc;
+
+         while (--isprite >= 0)
+         {
+            if (strcmp(sprites[isprite].name, name) == 0)
+            {
+               if (!add_sprite(output, out_buf, sprites+isprite, &argc, &argv))
+                  goto out; /* error in add_sprite */
+
+               break;
+            }
+         }
+
+         if (isprite < 0) /* sprite not found */
+         {
+            fprintf(stderr, "simpleover: --add='%s': sprite not found\n", name);
+            break;
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "simpleover: %s: unrecognized operation\n", argv[0]);
+         break;
+      }
+
+      result = 1; /* ok  */
+   }
+
+   /* Clean up the cache of sprites: */
+out:
+   while (--nsprites >= 0)
+   {
+      if (sprites[nsprites].buffer != NULL)
+         free(sprites[nsprites].buffer);
+
+      if (sprites[nsprites].file != NULL)
+         (void)fclose(sprites[nsprites].file);
+   }
+
+   return result;
+}
+
+int main(int argc, const char **argv)
+{
+   int result = 1; /* default to fail */
+
+   if (argc >= 2)
+   {
+      int argi = 2;
+      const char *output = NULL;
+      png_image image;
+
+      if (argc > 2 && argv[2][0] != '-'/*an operation*/)
+      {
+         output = argv[2];
+         argi = 3;
+      }
+
+      image.version = PNG_IMAGE_VERSION;
+      image.opaque = NULL;
+
+      if (png_image_begin_read_from_file(&image, argv[1]))
+      {
+         png_bytep buffer;
+
+         image.format = PNG_FORMAT_RGB; /* 24-bit RGB */
+
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         if (buffer != NULL)
+         {
+            png_color background = {0, 0xff, 0}; /* fully saturated green */
+
+            if (png_image_finish_read(&image, &background, buffer,
+               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
+            {
+               /* At this point png_image_finish_read has cleaned up the
+                * allocated data in png_image, and only the buffer needs to be
+                * freed.
+                *
+                * Perform the remaining operations:
+                */
+               if (simpleover_process(&image, buffer, argc-argi, argv+argi))
+               {
+                  /* Write the output: */
+                  if ((output != NULL &&
+                       png_image_write_to_file(&image, output,
+                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                        NULL/*colormap*/)) ||
+                      (output == NULL &&
+                       png_image_write_to_stdio(&image, stdout,
+                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                        NULL/*colormap*/)))
+                     result = 0;
+
+                  else
+                     fprintf(stderr, "simpleover: write %s: %s\n",
+                        output == NULL ? "stdout" : output, image.message);
+               }
+
+               /* else simpleover_process writes an error message */
+            }
+
+            else
+               fprintf(stderr, "simpleover: read %s: %s\n", argv[1],
+                   image.message);
+
+            free(buffer);
+         }
+
+         else
+         {
+            fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+
+            /* This is the only place where a 'free' is required; libpng does
+             * the cleanup on error and success, but in this case we couldn't
+             * complete the read because of running out of memory.
+             */
+            png_image_free(&image);
+         }
+      }
+
+      else
+      {
+         /* Failed to read the first argument: */
+         fprintf(stderr, "simpleover: %s: %s\n", argv[1], image.message);
+      }
+   }
+
+   else
+   {
+      /* Usage message */
+      fprintf(stderr,
+         "simpleover: usage: simpleover background.png [output.png]\n"
+         "  Output 'background.png' as a 24-bit RGB PNG file in 'output.png'\n"
+         "   or, if not given, stdout.  'background.png' will be composited\n"
+         "   on fully saturated green.\n"
+         "\n"
+         "  Optionally, before output, process additional PNG files:\n"
+         "\n"
+         "   --sprite=width,height,name {[--at=x,y] {sprite.png}}\n"
+         "    Produce a transparent sprite of size (width,height) and with\n"
+         "     name 'name'.\n"
+         "    For each sprite.png composite it using a Porter-Duff 'Over'\n"
+         "     operation at offset (x,y) in the sprite (defaulting to (0,0)).\n"
+         "     Input PNGs will be truncated to the area of the sprite.\n"
+         "\n"
+         "   --add='name' {x,y}\n"
+         "    Optionally, before output, composite a sprite, 'name', which\n"
+         "     must have been previously produced using --sprite, at each\n"
+         "     offset (x,y) in the output image.  Each sprite must fit\n"
+         "     completely within the output image.\n"
+         "\n"
+         "  PNG files are processed in the order they occur on the command\n"
+         "  line and thus the first PNG processed appears as the bottommost\n"
+         "  in the output image.\n");
+   }
+
+   return result;
+}
+#endif /* SIMPLIFIED_READ */
diff --git a/extern/libpng/contrib/gregbook/COPYING b/extern/libpng/contrib/gregbook/COPYING
new file mode 100644
index 0000000000..a3e9774796
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/COPYING
@@ -0,0 +1,340 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                    GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
+    stating that you changed the files and the date of any change.
+
+    b) You must cause any work that you distribute or publish, that in
+    whole or in part contains or is derived from the Program or any
+    part thereof, to be licensed as a whole at no charge to all third
+    parties under the terms of this License.
+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
+    announcement including an appropriate copyright notice and a
+    notice that there is no warranty (or else, saying that you provide
+    a warranty) and that users may redistribute the program under
+    these conditions, and telling the user how to view a copy of this
+    License.  (Exception: if the Program itself is interactive but
+    does not normally print such an announcement, your work based on
+    the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of Sections
+    1 and 2 above on a medium customarily used for software interchange; or,
+
+    b) Accompany it with a written offer, valid for at least three
+    years, to give any third party, for a charge no more than your
+    cost of physically performing source distribution, a complete
+    machine-readable copy of the corresponding source code, to be
+    distributed under the terms of Sections 1 and 2 above on a medium
+    customarily used for software interchange; or,
+
+    c) Accompany it with the information you received as to the offer
+    to distribute corresponding source code.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form with such
+    an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable.  However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+  7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+                            NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) year  name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Library General
+Public License instead of this License.
diff --git a/extern/libpng/contrib/gregbook/LICENSE b/extern/libpng/contrib/gregbook/LICENSE
new file mode 100644
index 0000000000..d9567178cb
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/LICENSE
@@ -0,0 +1,50 @@
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------
diff --git a/extern/libpng/contrib/gregbook/Makefile.mingw32 b/extern/libpng/contrib/gregbook/Makefile.mingw32
new file mode 100644
index 0000000000..3a3ff607e8
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/Makefile.mingw32
@@ -0,0 +1,131 @@
+# Sample makefile for rpng-win / rpng2-win / wpng using mingw32-gcc and make.
+# Greg Roelofs
+# Last modified:  2 June 2007
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
+#	generally for sale anymore, but it's the thought that counts,
+#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
+#
+# Invoke this makefile from a DOS-prompt window via:
+#
+#	make -f Makefile.mingw32
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are in subdirectories at the same level as the current subdirectory
+# (as indicated by the PNGDIR and ZDIR macros below).  It makes no assumptions
+# at all about the mingw32 installation tree (W32DIR).  Edit as appropriate.
+#
+# Note that the names of the dynamic and static libpng and zlib libraries
+# used below may change in later releases of the libraries.  This makefile
+# builds both statically and dynamically linked executables by default.
+# (You need only one set, but for testing it can be handy to have both.)
+
+
+# macros --------------------------------------------------------------------
+
+#PNGDIR = ../..#		for libpng-x.y.z/contrib/gregbook builds
+PNGDIR = ../libpng-win32
+PNGINC = -I$(PNGDIR)
+PNGLIBd = $(PNGDIR)/libpng.dll.a	# dynamically linked
+PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
+
+#ZDIR = ../../../zlib-win32#	for libpng-x.y.z/contrib/gregbook builds
+ZDIR = ../zlib-win32
+ZINC = -I$(ZDIR)
+ZLIBd = $(ZDIR)/libzdll.a
+ZLIBs = $(ZDIR)/libz.a
+
+# change this to be the path where mingw32 installs its stuff:
+W32DIR =
+#W32DIR = /usr/local/cross-tools/i386-mingw32msvc
+W32INC = -I$(W32DIR)/include
+W32LIB = $(W32DIR)/lib/libuser32.a $(W32DIR)/lib/libgdi32.a
+
+CC = gcc
+#CC = i386-mingw32msvc-gcc #	e.g., Linux -> Win32 cross-compilation
+LD = $(CC)
+RM = rm -f
+CPPFLAGS = $(INCS)
+CFLAGS = -O -Wall $(MINGW_CCFLAGS)
+# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
+# [-ansi, -pedantic and -W can also be used]
+LDFLAGS = $(MINGW_LDFLAGS)
+O = .o
+E = .exe
+
+INCS = $(PNGINC) $(ZINC) $(W32INC)
+RLIBSd = $(PNGLIBd) $(ZLIBd) $(W32LIB) -lm
+RLIBSs = $(PNGLIBs) $(ZLIBs) $(W32LIB) -lm
+WLIBSd = $(PNGLIBd) $(ZLIBd)
+WLIBSs = $(PNGLIBs) $(ZLIBs)
+
+RPNG   = rpng-win
+RPNG2  = rpng2-win
+WPNG   = wpng
+
+ROBJSd  = $(RPNG)$(O) readpng.pic$(O)
+ROBJS2d = $(RPNG2)$(O) readpng2.pic$(O)
+WOBJSd  = $(WPNG)$(O) writepng.pic$(O)
+
+RPNGs  = $(RPNG)-static
+RPNG2s = $(RPNG2)-static
+WPNGs  = $(WPNG)-static
+
+ROBJSs  = $(RPNG)$(O) readpng$(O)
+ROBJS2s = $(RPNG2)$(O) readpng2$(O)
+WOBJSs  = $(WPNG)$(O) writepng$(O)
+
+STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
+DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+%.pic$(O): %.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -DPNG_BUILD_DLL -o $@ $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNGs)$(E): $(ROBJSs)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJSs) $(RLIBSs)
+
+$(RPNG)$(E): $(ROBJSd)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJSd) $(RLIBSd)
+
+$(RPNG2s)$(E): $(ROBJS2s)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2s) $(RLIBSs)
+
+$(RPNG2)$(E): $(ROBJS2d)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2d) $(RLIBSd)
+
+$(WPNGs)$(E): $(WOBJSs)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJSs) $(WLIBSs)
+
+$(WPNG)$(E): $(WOBJSd)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJSd) $(WLIBSd)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O) readpng.pic$(O):	readpng.c readpng.h
+readpng2$(O) readpng2.pic$(O):	readpng2.c readpng2.h
+writepng$(O) writepng.pic$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+	$(RM) $(EXES)
+	$(RM) $(ROBJSs) $(ROBJS2s) $(WOBJSs)
+	$(RM) $(ROBJSd) $(ROBJS2d) $(WOBJSd)
diff --git a/extern/libpng/contrib/gregbook/Makefile.sgi b/extern/libpng/contrib/gregbook/Makefile.sgi
new file mode 100644
index 0000000000..94d61b4652
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/Makefile.sgi
@@ -0,0 +1,105 @@
+# Sample makefile for rpng-x / rpng2-x / wpng for SGI using cc and make.
+# Greg Roelofs
+# Last modified:  7 March 2002
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Buy some for friends
+#	and family, too.  (Not that this is a blatant plug or anything.)
+#
+# Invoke this makefile from a shell prompt in the usual way; for example:
+#
+#	make -f Makefile.sgi
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are both installed in /usr/local/{include,lib} (as indicated by the
+# PNG* and Z* macros below).  Edit as appropriate--choose only ONE each of
+# the PNGINC, PNGLIB, ZINC and ZLIB lines.
+#
+# This makefile builds dynamically linked executables (against libpng and zlib,
+# that is), but that can be changed by uncommenting the appropriate PNGLIB and
+# ZLIB lines.
+
+
+# macros --------------------------------------------------------------------
+
+PNGINC = -I/usr/local/include/libpng16
+PNGLIB = -L/usr/local/lib -lpng16	  # dynamically linked against libpng
+#PNGLIB = /usr/local/lib/libpng16.a # statically linked against libpng
+# or:
+#PNGINC = -I../..
+#PNGLIB = -L../.. -lpng
+#PNGLIB = ../../libpng.a
+
+ZINC = -I/usr/local/include
+ZLIB = -L/usr/local/lib -lz		# dynamically linked against zlib
+#ZLIB = /usr/local/lib/libz.a		# statically linked against zlib
+#ZINC = -I../zlib
+#ZLIB = -L../zlib -lz
+#ZLIB = ../../../zlib/libz.a
+
+XINC = -I/usr/include/X11		# old-style, stock X distributions
+XLIB = -L/usr/lib/X11 -lX11
+#XINC = -I/usr/openwin/include    	# Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+#XINC = -I/usr/X11R6/include		# new X distributions (XFree86, etc.)
+#XLIB = -L/usr/X11R6/lib -lX11
+
+INCS = $(PNGINC) $(ZINC) $(XINC)
+RLIBS = $(PNGLIB) $(ZLIB) $(XLIB) -lm
+WLIBS = $(PNGLIB) $(ZLIB)
+
+CC = cc
+LD = cc
+RM = rm -f
+# ABI must be the same as that used to build libpng.
+ABI =
+CPPFLAGS =
+CFLAGS = $(ABI) -O -fullwarn $(INCS)
+LDFLAGS = $(ABI)
+O = .o
+E =
+
+RPNG  = rpng-x
+RPNG2 = rpng2-x
+WPNG  = wpng
+
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+
+EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNG)$(E): $(ROBJS)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBS)
+
+$(RPNG2)$(E): $(ROBJS2)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBS)
+
+$(WPNG)$(E): $(WOBJS)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBS)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O):	readpng.c readpng.h
+readpng2$(O):	readpng2.c readpng2.h
+writepng$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/extern/libpng/contrib/gregbook/Makefile.unx b/extern/libpng/contrib/gregbook/Makefile.unx
new file mode 100644
index 0000000000..1a73e03bff
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/Makefile.unx
@@ -0,0 +1,134 @@
+# Sample makefile for rpng-x / rpng2-x / wpng using gcc and make.
+# Greg Roelofs
+# Last modified:  2 June 2007
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
+#	generally for sale anymore, but it's the thought that counts,
+#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
+#
+# Invoke this makefile from a shell prompt in the usual way; for example:
+#
+#	make -f Makefile.unx
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are installed in /usr/local/{include,lib} or as otherwise indicated by
+# the PNG* and Z* macros below.  Edit as appropriate--choose only ONE each of
+# the PNGINC, PNGLIBd, PNGLIBs, ZINC, ZLIBd and ZLIBs lines.
+#
+# This makefile builds both dynamically and statically linked executables
+# (against libpng and zlib, that is), but that can be changed by modifying
+# the "EXES =" line.  (You need only one set, but for testing it can be handy
+# to have both.)
+
+
+# macros --------------------------------------------------------------------
+
+#PNGDIR = /usr/local/lib
+#PNGINC = -I/usr/local/include/libpng16
+#PNGLIBd = -L$(PNGDIR) -lpng16 # dynamically linked, installed libpng
+#PNGLIBs = $(PNGDIR)/libpng16.a # statically linked, installed libpng
+# or:
+PNGDIR = ../..#	this one is for libpng-x.y.z/contrib/gregbook builds
+#PNGDIR = ../libpng
+PNGINC = -I$(PNGDIR)
+PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng16	# dynamically linked
+PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
+
+ZDIR = /usr/local/lib
+#ZDIR = /usr/lib64
+ZINC = -I/usr/local/include
+ZLIBd = -L$(ZDIR) -lz			# dynamically linked against zlib
+ZLIBs = $(ZDIR)/libz.a			# statically linked against zlib
+# or:
+#ZDIR = ../zlib
+#ZINC = -I$(ZDIR)
+#ZLIBd = -Wl,-rpath,$(ZDIR) -L$(ZDIR) -lz  # -rpath allows in-place testing
+#ZLIBs = $(ZDIR)/libz.a
+
+#XINC = -I/usr/include			# old-style, stock X distributions
+#XLIB = -L/usr/lib/X11 -lX11		#  (including SGI IRIX)
+#XINC = -I/usr/openwin/include		# Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+XINC = -I/usr/X11R6/include		# new X distributions (X.org, etc.)
+XLIB = -L/usr/X11R6/lib -lX11
+#XLIB = -L/usr/X11R6/lib64 -lX11	# e.g., Red Hat on AMD64
+
+INCS = $(PNGINC) $(ZINC) $(XINC)
+RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
+RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
+WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
+WLIBSs = $(PNGLIBs) $(ZLIBs) -lm
+
+CC = gcc
+LD = gcc
+RM = rm -f
+CPPFLAGS = $(INCS) -DFEATURE_LOOP
+CFLAGS = -O -Wall
+#CFLAGS = -O -W -Wall -Wextra -pedantic -ansi
+# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
+# [-ansi, -pedantic, -Wextra, and -W can also be used]
+LDFLAGS =
+O = .o
+E =
+
+RPNG   = rpng-x
+RPNG2  = rpng2-x
+WPNG   = wpng
+
+RPNGs  = $(RPNG)-static
+RPNG2s = $(RPNG2)-static
+WPNGs  = $(WPNG)-static
+
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+
+STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
+DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNGs)$(E): $(ROBJS)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSs)
+
+$(RPNG)$(E): $(ROBJS)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSd)
+
+$(RPNG2s)$(E): $(ROBJS2)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSs)
+
+$(RPNG2)$(E): $(ROBJS2)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSd)
+
+$(WPNGs)$(E): $(WOBJS)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSs)
+
+$(WPNG)$(E): $(WOBJS)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSd)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O):	readpng.c readpng.h
+readpng2$(O):	readpng2.c readpng2.h
+writepng$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/extern/libpng/contrib/gregbook/Makefile.w32 b/extern/libpng/contrib/gregbook/Makefile.w32
new file mode 100644
index 0000000000..ab7dcf7cae
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/Makefile.w32
@@ -0,0 +1,114 @@
+# Sample makefile for rpng-win / rpng2-win / wpng using MSVC and NMAKE.
+# Greg Roelofs
+# Last modified:  2 June 2007
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
+#	generally for sale anymore, but it's the thought that counts,
+#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
+#
+# Invoke this makefile from a DOS prompt window via:
+#
+#	%devstudio%\vc\bin\vcvars32.bat
+#	nmake -nologo -f Makefile.w32
+#
+# where %devstudio% is the installation directory for MSVC / DevStudio.  If
+# you get "environment out of space" errors, create a desktop shortcut with
+# "c:\windows\command.com /e:4096" as the program command line and set the
+# working directory to this directory.  Then double-click to open the new
+# DOS-prompt window with a bigger environment and retry the commands above.
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are in subdirectories at the same level as the current subdirectory
+# (as indicated by the PNGPATH and ZPATH macros below).  Edit as appropriate.
+#
+# Note that the names of the dynamic and static libpng and zlib libraries
+# used below may change in later releases of the libraries.  This makefile
+# builds statically linked executables, but that can be changed by uncom-
+# menting the appropriate PNGLIB and ZLIB lines.
+
+!include <ntwin32.mak>
+
+
+# macros --------------------------------------------------------------------
+
+PNGPATH = ../libpng
+PNGINC = -I$(PNGPATH)
+#PNGLIB = $(PNGPATH)/pngdll.lib
+PNGLIB = $(PNGPATH)/libpng.lib
+
+ZPATH = ../zlib
+ZINC = -I$(ZPATH)
+#ZLIB = $(ZPATH)/zlibdll.lib
+ZLIB = $(ZPATH)/zlibstat.lib
+
+WINLIBS = -defaultlib:user32.lib gdi32.lib
+# ["real" apps may also need comctl32.lib, comdlg32.lib, winmm.lib, etc.]
+
+INCS = $(PNGINC) $(ZINC)
+RLIBS = $(PNGLIB) $(ZLIB) $(WINLIBS)
+WLIBS = $(PNGLIB) $(ZLIB)
+
+CC = cl
+LD = link
+RM = del
+CPPFLAGS = $(INCS)
+CFLAGS = -nologo -O -W3 $(cvars)
+# [note that -W3 is an MSVC-specific compilation flag ("all warnings on")]
+# [see %devstudio%\vc\include\win32.mak for cvars macro definition]
+O = .obj
+E = .exe
+
+RLDFLAGS = -nologo -subsystem:windows
+WLDFLAGS = -nologo
+
+RPNG  = rpng-win
+RPNG2 = rpng2-win
+WPNG  = wpng
+
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+
+EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNG)$(E): $(ROBJS)
+	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS) $(RLIBS)
+
+$(RPNG2)$(E): $(ROBJS2)
+	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS2) $(RLIBS)
+
+$(WPNG)$(E): $(WOBJS)
+	$(LD) $(WLDFLAGS) -out:$@ $(WOBJS) $(WLIBS)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O):	readpng.c readpng.h
+readpng2$(O):	readpng2.c readpng2.h
+writepng$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+#	ideally we could just do this:
+#	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
+#	...but the Windows "DEL" command is none too bright, so:
+	$(RM) r*$(E)
+	$(RM) w*$(E)
+	$(RM) r*$(O)
+	$(RM) w*$(O)
diff --git a/extern/libpng/contrib/gregbook/README b/extern/libpng/contrib/gregbook/README
new file mode 100644
index 0000000000..90e28f7ce5
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/README
@@ -0,0 +1,186 @@
+                     ===========================
+                      PNG: The Definitive Guide
+                     ===========================
+
+                             Source Code
+
+Chapters 13, 14 and 15 of "PNG: The Definitive Guide" discuss three free,
+cross-platform demo programs that show how to use the libpng reference
+library:  rpng, rpng2 and wpng.  rpng and rpng2 are viewers; the first is
+a very simple example that that shows how a standard file-viewer might use
+libpng, while the second is designed to process streaming data and shows
+how a web browser might be written.  wpng is a simple command-line program
+that reads binary PGM and PPM files (the ``raw'' grayscale and RGB subsets
+of PBMPLUS/NetPBM) and converts them to PNG.
+
+The source code for all three demo programs currently compiles under
+Unix, OpenVMS, and 32-bit Windows.  (Special thanks to Martin Zinser,
+zinser at decus.de, for making the necessary changes for OpenVMS and for
+providing an appropriate build script.)  Build instructions can be found
+below.
+
+Files:
+
+   README             this file
+   LICENSE            terms of distribution and reuse (BSD-like or GNU GPL)
+   COPYING            GNU General Public License (GPL)
+
+   Makefile.unx       Unix makefile
+   Makefile.w32       Windows (MSVC) makefile
+   makevms.com        OpenVMS build script
+
+   rpng-win.c         Windows front end for the basic viewer
+   rpng-x.c           X Window System (Unix, OpenVMS) front end
+   readpng.c          generic back end for the basic viewer
+   readpng.h          header file for the basic viewer
+
+   rpng2-win.c        Windows front end for the progressive viewer
+   rpng2-x.c          X front end for the progressive viewer
+   readpng2.c         generic back end for the progressive viewer
+   readpng2.h         header file for the progressive viewer
+
+   wpng.c             generic (text) front end for the converter
+   writepng.c         generic back end for the converter
+   writepng.h         header file for the converter
+
+   toucan.png         transparent PNG for testing (by Stefan Schneider)
+
+Note that, although the programs are designed to be functional, their
+primary purpose is to illustrate how to use libpng to add PNG support to
+other programs.  As such, their user interfaces are crude and definitely
+are not intended for everyday use.
+
+Please see http://www.libpng.org/pub/png/pngbook.html for further infor-
+mation and links to the latest version of the source code, and Chapters
+13-15 of the book for detailed discussion of the three programs.
+
+Greg Roelofs
+https://pobox.com/~newt/greg_contact.html
+16 March 2008
+
+
+BUILD INSTRUCTIONS
+
+ - Prerequisites (in order of compilation):
+
+      - zlib            https://zlib.net/
+      - libpng          http://www.libpng.org/pub/png/libpng.html
+      - pngbook         http://www.libpng.org/pub/png/book/sources.html
+
+     The pngbook demo programs are explicitly designed to demonstrate proper
+     coding techniques for using the libpng reference library.  As a result,
+     you need to download and build both zlib (on which libpng depends) and
+     libpng.  A common build setup is to place the zlib, libpng and pngbook
+     subdirectory trees ("folders") in the same parent directory.  Then the
+     libpng build can refer to files in ../zlib (or ..\zlib or [-.zlib]),
+     and similarly for the pngbook build.
+
+     Note that all three packages are designed to be built from a command
+     line by default; those who wish to use a graphical or other integrated
+     development environments are on their own.
+
+
+ - Unix:
+
+     Unpack the latest pngbook sources (which should correspond to this
+     README file) into a directory and change into that directory.
+
+     Copy Makefile.unx to Makefile and edit the PNG* and Z* variables
+     appropriately (possibly also the X* variables if necessary).
+
+     make
+
+     There is no "install" target, so copy the three executables somewhere
+     in your path or run them from the current directory.  All three will
+     print a basic usage screen when run without any command-line arguments;
+     see the book for more details.
+
+
+ - Windows:
+
+     Unpack the latest pngbook sources (which should correspond to this
+     README file) into a folder, open a "DOS shell" or "command prompt"
+     or equivalent command-line window, and cd into the folder where you
+     unpacked the source code.
+
+     For MSVC, set up the necessary environment variables by invoking
+
+        %devstudio%\vc\bin\vcvars32.bat
+
+     where where %devstudio% is the installation directory for MSVC /
+     DevStudio.  If you get "environment out of space" errors under 95/98,
+     create a desktop shortcut with "c:\windows\command.com /e:4096" as
+     the program command line and set the working directory to the pngbook
+     directory.  Then double-click to open the new DOS-prompt window with
+     a bigger environment and retry the commands above.
+
+     Copy Makefile.w32 to Makefile and edit the PNGPATH and ZPATH variables
+     appropriately (possibly also the "INC" and "LIB" variables if needed).
+     Note that the names of the dynamic and static libpng and zlib libraries
+     used in the makefile may change in later releases of the libraries.
+     Also note that, as of libpng version 1.0.5, MSVC DLL builds do not work.
+     This makefile therefore builds statically linked executables, but if
+     the DLL problems ever get fixed, uncommenting the appropriate PNGLIB
+     and ZLIB lines will build dynamically linked executables instead.
+
+     Do the build by typing
+
+        nmake
+
+     The result should be three executables:  rpng-win.exe, rpng2-win.exe,
+     and wpng.exe.  Copy them somewhere in your PATH or run them from the
+     current folder.  Like the Unix versions, the two windowed programs
+     (rpng and rpng2) now display a usage screen in a console window when
+     invoked without command-line arguments; this is new behavior as of
+     the June 2001 release.  Note that the programs use the Unix-style "-"
+     character to specify options, instead of the more common DOS/Windows
+     "/" character.  (For example:  "rpng2-win -bgpat 4 foo.png", not
+     "rpng2-win /bgpat 4 foo.png")
+
+
+ - OpenVMS:
+
+     Unpack the pngbook sources into a subdirectory and change into that
+     subdirectory.
+
+     Edit makevms.com appropriately, specifically the zpath and pngpath
+     variables.
+
+     @makevms
+
+     To run the programs, they probably first need to be set up as "foreign
+     symbols," with "disk" and "dir" set appropriately:
+
+     $ rpng  == "$disk:[dir]rpng-x.exe"
+     $ rpng2 == "$disk:[dir]rpng2-x.exe"
+     $ wpng  == "$disk:[dir]wpng.exe"
+
+     All three will print a basic usage screen when run without any command-
+     line arguments; see the book for more details.  Note that the options
+     style is Unix-like, i.e., preceded by "-" rather than "/".
+
+
+RUNNING THE PROGRAMS:  (VERY) BRIEF INTRO
+
+     rpng is a simple PNG viewer that can display transparent PNGs with a
+     specified background color; for example,
+
+        rpng -bgcolor \#ff0000 toucan.png
+
+     would display the image with a red background.  rpng2 is a progressive
+     viewer that simulates a web browser in some respects; it can display
+     images against either a background color or a dynamically generated
+     background image.  For example:
+
+        rpng2 -bgpat 16 toucan.png
+
+     wpng is a purely command-line image converter from binary PBMPLUS/NetPBM
+     format (.pgm or .ppm) to PNG; for example,
+
+        wpng -time < toucan-notrans.ppm > toucan-notrans.png
+
+     would convert the specified PPM file (using redirection) to PNG, auto-
+     matically setting the PNG modification-time chunk.
+
+     All options can be abbreviated to the shortest unique value; for example,
+     "-bgc" for -bgcolor (versus "-bgp" for -bgpat), or "-g" for -gamma.
diff --git a/extern/libpng/contrib/gregbook/makevms.com b/extern/libpng/contrib/gregbook/makevms.com
new file mode 100644
index 0000000000..f32bcaba7f
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/makevms.com
@@ -0,0 +1,132 @@
+$!------------------------------------------------------------------------------
+$! make "PNG: The Definitive Guide" demo programs (for X) under OpenVMS
+$!
+$! Script created by Martin Zinser for libpng; modified by Greg Roelofs
+$! for standalone pngbook source distribution.
+$!
+$!
+$!    Set locations where zlib and libpng sources live.
+$!
+$ zpath   = ""
+$ pngpath = ""
+$!
+$ if f$search("[---.zlib]zlib.h").nes."" then zpath = "[---.zlib]"
+$ if f$search("[--]png.h").nes."" then pngpath = "[--]"
+$!
+$ if f$search("[-.zlib]zlib.h").nes."" then zpath = "[-.zlib]"
+$ if f$search("[-.libpng]png.h").nes."" then pngpath = "[-.libpng]"
+$!
+$ if zpath .eqs. ""
+$ then
+$   write sys$output "zlib include not found. Exiting..."
+$   exit 2
+$ endif
+$!
+$ if pngpath .eqs. ""
+$ then
+$   write sys$output "libpng include not found. Exiting..."
+$   exit 2
+$ endif
+$!
+$!    Look for the compiler used.
+$!
+$ ccopt="/include=(''zpath',''pngpath')"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$ open/write lopt lib.opt
+$ write lopt "''pngpath'libpng.olb/lib"
+$ write lopt "''zpath'libz.olb/lib"
+$ close lopt
+$ open/write xopt x11.opt
+$ write xopt "sys$library:decw$xlibshr.exe/share"
+$ close xopt
+$!
+$!    Build 'em.
+$!
+$ write sys$output "Compiling PNG book programs ..."
+$   CALL MAKE readpng.OBJ "cc ''CCOPT' readpng" -
+	readpng.c readpng.h
+$   CALL MAKE readpng2.OBJ "cc ''CCOPT' readpng2" -
+	readpng2.c readpng2.h
+$   CALL MAKE writepng.OBJ "cc ''CCOPT' writepng" -
+	writepng.c writepng.h
+$   write sys$output "Building rpng-x..."
+$   CALL MAKE rpng-x.OBJ "cc ''CCOPT' rpng-x" -
+	rpng-x.c readpng.h
+$   call make rpng-x.exe -
+	"LINK rpng-x,readpng,lib.opt/opt,x11.opt/opt" -
+	rpng-x.obj readpng.obj
+$   write sys$output "Building rpng2-x..."
+$   CALL MAKE rpng2-x.OBJ "cc ''CCOPT' rpng2-x" -
+	rpng2-x.c readpng2.h
+$   call make rpng2-x.exe -
+	"LINK rpng2-x,readpng2,lib.opt/opt,x11.opt/opt" -
+	rpng2-x.obj readpng2.obj
+$   write sys$output "Building wpng..."
+$   CALL MAKE wpng.OBJ "cc ''CCOPT' wpng" -
+	wpng.c writepng.h
+$   call make wpng.exe -
+	"LINK wpng,writepng,lib.opt/opt" -
+	wpng.obj writepng.obj
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE
diff --git a/extern/libpng/contrib/gregbook/readpng.c b/extern/libpng/contrib/gregbook/readpng.c
new file mode 100644
index 0000000000..fad9b536ab
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/readpng.c
@@ -0,0 +1,323 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                              readpng.c
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007,2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <zlib.h>
+
+#include "png.h"        /* libpng header */
+#include "readpng.h"    /* typedefs, common macros, public prototypes */
+
+/* future versions of libpng will provide this macro: */
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr)   ((png_ptr)->jmpbuf)
+#endif
+
+
+static png_structp png_ptr = NULL;
+static png_infop info_ptr = NULL;
+
+png_uint_32  width, height;
+int  bit_depth, color_type;
+uch  *image_data = NULL;
+
+
+void readpng_version_info(void)
+{
+    fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
+      PNG_LIBPNG_VER_STRING, png_libpng_ver);
+    fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
+      ZLIB_VERSION, zlib_version);
+}
+
+
+/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
+
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
+{
+    uch sig[8];
+
+
+    /* first do a quick check that the file really is a PNG image; could
+     * have used slightly more general png_sig_cmp() function instead */
+
+    fread(sig, 1, 8, infile);
+    if (png_sig_cmp(sig, 0, 8))
+        return 1;   /* bad signature */
+
+
+    /* could pass pointers to user-defined error handlers instead of NULLs: */
+
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), NULL, NULL,
+        NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        return 4;   /* out of memory */
+    }
+
+
+    /* we could create a second info struct here (end_info), but it's only
+     * useful if we want to keep pre- and post-IDAT chunk info separated
+     * (mainly for PNG-aware image editors and converters) */
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+
+
+    png_init_io(png_ptr, infile);
+    png_set_sig_bytes(png_ptr, 8);  /* we already read the 8 signature bytes */
+
+    png_read_info(png_ptr, info_ptr);  /* read all PNG info up to image data */
+
+
+    /* alternatively, could make separate calls to png_get_image_width(),
+     * etc., but want bit_depth and color_type for later [don't care about
+     * compression_type and filter_type => NULLs] */
+
+    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+      NULL, NULL, NULL);
+    *pWidth = width;
+    *pHeight = height;
+
+
+    /* OK, that's all we need for now; return happy */
+
+    return 0;
+}
+
+
+
+
+/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
+ * scales values to 8-bit if necessary */
+
+int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
+{
+    png_color_16p pBackground;
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+
+
+    if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
+        return 1;
+
+    /* it is not obvious from the libpng documentation, but this function
+     * takes a pointer to a pointer, and it always returns valid red, green
+     * and blue values, regardless of color_type: */
+
+    png_get_bKGD(png_ptr, info_ptr, &pBackground);
+
+
+    /* however, it always returns the raw bKGD data, regardless of any
+     * bit-depth transformations, so check depth and adjust if necessary */
+
+    if (bit_depth == 16) {
+        *red   = pBackground->red   >> 8;
+        *green = pBackground->green >> 8;
+        *blue  = pBackground->blue  >> 8;
+    } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
+        if (bit_depth == 1)
+            *red = *green = *blue = pBackground->gray? 255 : 0;
+        else if (bit_depth == 2)
+            *red = *green = *blue = (255/3) * pBackground->gray;
+        else /* bit_depth == 4 */
+            *red = *green = *blue = (255/15) * pBackground->gray;
+    } else {
+        *red   = (uch)pBackground->red;
+        *green = (uch)pBackground->green;
+        *blue  = (uch)pBackground->blue;
+    }
+
+    return 0;
+}
+
+
+
+
+/* display_exponent == LUT_exponent * CRT_exponent */
+
+uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
+{
+    double  gamma;
+    png_uint_32  i, rowbytes;
+    png_bytepp  row_pointers = NULL;
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        free(image_data);
+        image_data = NULL;
+        free(row_pointers);
+        row_pointers = NULL;
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return NULL;
+    }
+
+
+    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
+     * transparency chunks to full alpha channel; strip 16-bit-per-sample
+     * images to 8 bits per sample; and convert grayscale to RGB[A] */
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_expand(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+        png_set_expand(png_ptr);
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+        png_set_expand(png_ptr);
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+    if (bit_depth == 16)
+#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+        png_set_scale_16(png_ptr);
+#  else
+        png_set_strip_16(png_ptr);
+#  endif
+#endif
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+        png_set_gray_to_rgb(png_ptr);
+
+
+    /* unlike the example in the libpng documentation, we have *no* idea where
+     * this file may have come from--so if it doesn't have a file gamma, don't
+     * do any correction ("do no harm") */
+
+    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
+        png_set_gamma(png_ptr, display_exponent, gamma);
+
+
+    /* all transformations have been registered; now update info_ptr data,
+     * get rowbytes and channels, and allocate image memory */
+
+    png_read_update_info(png_ptr, info_ptr);
+
+    *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+    *pChannels = (int)png_get_channels(png_ptr, info_ptr);
+
+    /* Guard against integer overflow */
+    if (height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, "readpng:  image_data buffer would be too large\n",
+        return NULL;
+    }
+
+    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return NULL;
+    }
+    if ((row_pointers = (png_bytepp)malloc(height*sizeof(png_bytep))) == NULL) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        free(image_data);
+        image_data = NULL;
+        return NULL;
+    }
+
+    Trace((stderr, "readpng_get_image:  channels = %d, rowbytes = %ld, height = %ld\n",
+        *pChannels, rowbytes, height));
+
+
+    /* set the individual row_pointers to point at the correct offsets */
+
+    for (i = 0;  i < height;  ++i)
+        row_pointers[i] = image_data + i*rowbytes;
+
+
+    /* now we can go ahead and just read the whole image */
+
+    png_read_image(png_ptr, row_pointers);
+
+
+    /* and we're done!  (png_read_end() can be omitted if no processing of
+     * post-IDAT text/time/etc. is desired) */
+
+    free(row_pointers);
+    row_pointers = NULL;
+
+    png_read_end(png_ptr, NULL);
+
+    return image_data;
+}
+
+
+void readpng_cleanup(int free_image_data)
+{
+    if (free_image_data && image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+
+    if (png_ptr && info_ptr) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        png_ptr = NULL;
+        info_ptr = NULL;
+    }
+}
diff --git a/extern/libpng/contrib/gregbook/readpng.h b/extern/libpng/contrib/gregbook/readpng.h
new file mode 100644
index 0000000000..fad9fe3b4c
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/readpng.h
@@ -0,0 +1,88 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                              readpng.h
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+
+
+/* prototypes for public functions in readpng.c */
+
+void readpng_version_info(void);
+
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight);
+
+int readpng_get_bgcolor(uch *bg_red, uch *bg_green, uch *bg_blue);
+
+uch *readpng_get_image(double display_exponent, int *pChannels,
+                       ulg *pRowbytes);
+
+void readpng_cleanup(int free_image_data);
diff --git a/extern/libpng/contrib/gregbook/readpng2.c b/extern/libpng/contrib/gregbook/readpng2.c
new file mode 100644
index 0000000000..610b3cd87e
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/readpng2.c
@@ -0,0 +1,521 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                 readpng2.c
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2015 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+     2015-11-12 - Check return value of png_get_bKGD() (Glenn R-P)
+     2017-04-22 - Guard against integer overflow (Glenn R-P)
+
+  ---------------------------------------------------------------------------*/
+
+
+#include <stdlib.h>     /* for exit() prototype */
+#include <setjmp.h>
+
+#include <zlib.h>
+#include "png.h"        /* libpng header from the local directory */
+#include "readpng2.h"   /* typedefs, common macros, public prototypes */
+
+
+/* local prototypes */
+
+static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr);
+static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
+                                 png_uint_32 row_num, int pass);
+static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr);
+static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg);
+static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg);
+
+
+
+
+void readpng2_version_info(void)
+{
+    fprintf(stderr, "   Compiled with libpng %s; using libpng %s\n",
+      PNG_LIBPNG_VER_STRING, png_libpng_ver);
+
+    fprintf(stderr, "   and with zlib %s; using zlib %s.\n",
+      ZLIB_VERSION, zlib_version);
+}
+
+
+
+
+int readpng2_check_sig(uch *sig, int num)
+{
+    return !png_sig_cmp(sig, 0, num);
+}
+
+
+
+
+/* returns 0 for success, 2 for libpng problem, 4 for out of memory */
+
+int readpng2_init(mainprog_info *mainprog_ptr)
+{
+    png_structp  png_ptr;       /* note:  temporary variables! */
+    png_infop  info_ptr;
+
+
+    /* could also replace libpng warning-handler (final NULL), but no need: */
+
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), mainprog_ptr,
+      readpng2_error_handler, readpng2_warning_handler);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        return 4;   /* out of memory */
+    }
+
+
+    /* we could create a second info struct here (end_info), but it's only
+     * useful if we want to keep pre- and post-IDAT chunk info separated
+     * (mainly for PNG-aware image editors and converters) */
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function, unless an alternate error handler was installed--
+     * but compatible error handlers must either use longjmp() themselves
+     * (as in this program) or exit immediately, so here we are: */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+    /* prepare the reader to ignore all recognized chunks whose data won't be
+     * used, i.e., all chunks recognized by libpng except for IHDR, PLTE, IDAT,
+     * IEND, tRNS, bKGD, gAMA, and sRGB (small performance improvement) */
+    {
+        /* These byte strings were copied from png.h.  If a future version
+         * of readpng2.c recognizes more chunks, add them to this list.
+         */
+        static const png_byte chunks_to_process[] = {
+            98,  75,  71,  68, '\0',  /* bKGD */
+           103,  65,  77,  65, '\0',  /* gAMA */
+           115,  82,  71,  66, '\0',  /* sRGB */
+           };
+
+       /* Ignore all chunks except for IHDR, PLTE, tRNS, IDAT, and IEND */
+       png_set_keep_unknown_chunks(png_ptr, -1 /* PNG_HANDLE_CHUNK_NEVER */,
+          NULL, -1);
+
+       /* But do not ignore chunks in the "chunks_to_process" list */
+       png_set_keep_unknown_chunks(png_ptr,
+          0 /* PNG_HANDLE_CHUNK_AS_DEFAULT */, chunks_to_process,
+          sizeof(chunks_to_process)/5);
+    }
+#endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */
+
+
+    /* instead of doing png_init_io() here, now we set up our callback
+     * functions for progressive decoding */
+
+    png_set_progressive_read_fn(png_ptr, mainprog_ptr,
+      readpng2_info_callback, readpng2_row_callback, readpng2_end_callback);
+
+
+    /* make sure we save our pointers for use in readpng2_decode_data() */
+
+    mainprog_ptr->png_ptr = png_ptr;
+    mainprog_ptr->info_ptr = info_ptr;
+
+
+    /* and that's all there is to initialization */
+
+    return 0;
+}
+
+
+
+
+/* returns 0 for success, 2 for libpng (longjmp) problem */
+
+int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* hand off the next chunk of input data to libpng for decoding */
+
+    png_process_data(png_ptr, info_ptr, rawbuf, length);
+
+    return 0;
+}
+
+
+
+
+static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr)
+{
+    mainprog_info  *mainprog_ptr;
+    int  color_type, bit_depth;
+    png_uint_32 width, height;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+    double  gamma;
+#else
+    png_fixed_point gamma;
+#endif
+
+
+    /* setjmp() doesn't make sense here, because we'd either have to exit(),
+     * longjmp() ourselves, or return control to libpng, which doesn't want
+     * to see us again.  By not doing anything here, libpng will instead jump
+     * to readpng2_decode_data(), which can return an error value to the main
+     * program. */
+
+
+    /* retrieve the pointer to our special-purpose struct, using the png_ptr
+     * that libpng passed back to us (i.e., not a global this time--there's
+     * no real difference for a single image, but for a multithreaded browser
+     * decoding several PNG images at the same time, one needs to avoid mixing
+     * up different images' structs) */
+
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+
+    if (mainprog_ptr == NULL) {         /* we be hosed */
+        fprintf(stderr,
+          "readpng2 error:  main struct not recoverable in info_callback.\n");
+        fflush(stderr);
+        return;
+        /*
+         * Alternatively, we could call our error-handler just like libpng
+         * does, which would effectively terminate the program.  Since this
+         * can only happen if png_ptr gets redirected somewhere odd or the
+         * main PNG struct gets wiped, we're probably toast anyway.  (If
+         * png_ptr itself is NULL, we would not have been called.)
+         */
+    }
+
+
+    /* this is just like in the non-progressive case */
+
+    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+       NULL, NULL, NULL);
+    mainprog_ptr->width = (ulg)width;
+    mainprog_ptr->height = (ulg)height;
+
+
+    /* since we know we've read all of the PNG file's "header" (i.e., up
+     * to IDAT), we can check for a background color here */
+
+    if (mainprog_ptr->need_bgcolor)
+    {
+        png_color_16p pBackground;
+
+        /* it is not obvious from the libpng documentation, but this function
+         * takes a pointer to a pointer, and it always returns valid red,
+         * green and blue values, regardless of color_type: */
+        if (png_get_bKGD(png_ptr, info_ptr, &pBackground))
+        {
+
+           /* however, it always returns the raw bKGD data, regardless of any
+            * bit-depth transformations, so check depth and adjust if necessary
+            */
+           if (bit_depth == 16) {
+               mainprog_ptr->bg_red   = pBackground->red   >> 8;
+               mainprog_ptr->bg_green = pBackground->green >> 8;
+               mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
+           } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
+               if (bit_depth == 1)
+                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                     mainprog_ptr->bg_blue = pBackground->gray? 255 : 0;
+               else if (bit_depth == 2)
+                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                     mainprog_ptr->bg_blue = (255/3) * pBackground->gray;
+               else /* bit_depth == 4 */
+                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                     mainprog_ptr->bg_blue = (255/15) * pBackground->gray;
+           } else {
+               mainprog_ptr->bg_red   = (uch)pBackground->red;
+               mainprog_ptr->bg_green = (uch)pBackground->green;
+               mainprog_ptr->bg_blue  = (uch)pBackground->blue;
+           }
+        }
+    }
+
+
+    /* as before, let libpng expand palette images to RGB, low-bit-depth
+     * grayscale images to 8 bits, transparency chunks to full alpha channel;
+     * strip 16-bit-per-sample images to 8 bits per sample; and convert
+     * grayscale to RGB[A] */
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_expand(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+        png_set_expand(png_ptr);
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+        png_set_expand(png_ptr);
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+    if (bit_depth == 16)
+#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+        png_set_scale_16(png_ptr);
+#  else
+        png_set_strip_16(png_ptr);
+#  endif
+#endif
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+        png_set_gray_to_rgb(png_ptr);
+
+
+    /* Unlike the basic viewer, which was designed to operate on local files,
+     * this program is intended to simulate a web browser--even though we
+     * actually read from a local file, too.  But because we are pretending
+     * that most of the images originate on the Internet, we follow the recom-
+     * mendation of the sRGB proposal and treat unlabelled images (no gAMA
+     * chunk) as existing in the sRGB color space.  That is, we assume that
+     * such images have a file gamma of 0.45455, which corresponds to a PC-like
+     * display system.  This change in assumptions will have no effect on a
+     * PC-like system, but on a Mac, SGI, NeXT or other system with a non-
+     * identity lookup table, it will darken unlabelled images, which effec-
+     * tively favors images from PC-like systems over those originating on
+     * the local platform.  Note that mainprog_ptr->display_exponent is the
+     * "gamma" value for the entire display system, i.e., the product of
+     * LUT_exponent and CRT_exponent. */
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
+        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, gamma);
+    else
+        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, 0.45455);
+#else
+    if (png_get_gAMA_fixed(png_ptr, info_ptr, &gamma))
+        png_set_gamma_fixed(png_ptr,
+            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), gamma);
+    else
+        png_set_gamma_fixed(png_ptr,
+            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), 45455);
+#endif
+
+    /* we'll let libpng expand interlaced images, too */
+
+    mainprog_ptr->passes = png_set_interlace_handling(png_ptr);
+
+
+    /* all transformations have been registered; now update info_ptr data and
+     * then get rowbytes and channels */
+
+    png_read_update_info(png_ptr, info_ptr);
+
+    mainprog_ptr->rowbytes = (int)png_get_rowbytes(png_ptr, info_ptr);
+    mainprog_ptr->channels = png_get_channels(png_ptr, info_ptr);
+
+
+    /* Call the main program to allocate memory for the image buffer and
+     * initialize windows and whatnot.  (The old-style function-pointer
+     * invocation is used for compatibility with a few supposedly ANSI
+     * compilers that nevertheless barf on "fn_ptr()"-style syntax.) */
+
+    (*mainprog_ptr->mainprog_init)();
+
+
+    /* and that takes care of initialization */
+
+    return;
+}
+
+
+
+
+
+static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
+                                  png_uint_32 row_num, int pass)
+{
+    mainprog_info  *mainprog_ptr;
+
+
+    /* first check whether the row differs from the previous pass; if not,
+     * nothing to combine or display */
+
+    if (!new_row)
+        return;
+
+
+    /* retrieve the pointer to our special-purpose struct so we can access
+     * the old rows and image-display callback function */
+
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+
+
+    /* save the pass number for optional use by the front end */
+
+    mainprog_ptr->pass = pass;
+
+
+    /* have libpng either combine the new row data with the existing row data
+     * from previous passes (if interlaced) or else just copy the new row
+     * into the main program's image buffer */
+
+    png_progressive_combine_row(png_ptr, mainprog_ptr->row_pointers[row_num],
+      new_row);
+
+
+    /* finally, call the display routine in the main program with the number
+     * of the row we just updated */
+
+    (*mainprog_ptr->mainprog_display_row)(row_num);
+
+
+    /* and we're ready for more */
+
+    return;
+}
+
+
+
+
+
+static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)
+{
+    mainprog_info  *mainprog_ptr;
+
+
+    /* retrieve the pointer to our special-purpose struct */
+
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+
+
+    /* let the main program know that it should flush any buffered image
+     * data to the display now and set a "done" flag or whatever, but note
+     * that it SHOULD NOT DESTROY THE PNG STRUCTS YET--in other words, do
+     * NOT call readpng2_cleanup() either here or in the finish_display()
+     * routine; wait until control returns to the main program via
+     * readpng2_decode_data() */
+
+    (*mainprog_ptr->mainprog_finish_display)();
+
+
+    /* all done */
+
+    (void)info_ptr; /* Unused */
+
+    return;
+}
+
+
+
+
+
+void readpng2_cleanup(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+    if (png_ptr && info_ptr)
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+    mainprog_ptr->png_ptr = NULL;
+    mainprog_ptr->info_ptr = NULL;
+}
+
+
+static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg)
+{
+    fprintf(stderr, "readpng2 libpng warning: %s\n", msg);
+    fflush(stderr);
+    (void)png_ptr; /* Unused */
+}
+
+
+static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg)
+{
+    mainprog_info  *mainprog_ptr;
+
+    /* This function, aside from the extra step of retrieving the "error
+     * pointer" (below) and the fact that it exists within the application
+     * rather than within libpng, is essentially identical to libpng's
+     * default error handler.  The second point is critical:  since both
+     * setjmp() and longjmp() are called from the same code, they are
+     * guaranteed to have compatible notions of how big a jmp_buf is,
+     * regardless of whether _BSD_SOURCE or anything else has (or has not)
+     * been defined. */
+
+    fprintf(stderr, "readpng2 libpng error: %s\n", msg);
+    fflush(stderr);
+
+    mainprog_ptr = png_get_error_ptr(png_ptr);
+    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
+        fprintf(stderr,
+          "readpng2 severe error:  jmpbuf not recoverable; terminating.\n");
+        fflush(stderr);
+        exit(99);
+    }
+
+    /* Now we have our data structure we can use the information in it
+     * to return control to our own higher level code (all the points
+     * where 'setjmp' is called in this file.)  This will work with other
+     * error handling mechanisms as well - libpng always calls png_error
+     * when it can proceed no further, thus, so long as the error handler
+     * is intercepted, application code can do its own error recovery.
+     */
+    longjmp(mainprog_ptr->jmpbuf, 1);
+}
diff --git a/extern/libpng/contrib/gregbook/readpng2.h b/extern/libpng/contrib/gregbook/readpng2.h
new file mode 100644
index 0000000000..6b3660d7c1
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/readpng2.h
@@ -0,0 +1,116 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                 readpng2.h
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+
+enum rpng2_states {
+    kPreInit = 0,
+    kWindowInit,
+    kDone
+};
+
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+
+typedef struct _mainprog_info {
+    double display_exponent;
+    ulg width;
+    ulg height;
+    void *png_ptr;
+    void *info_ptr;
+    void (*mainprog_init)(void);
+    void (*mainprog_display_row)(ulg row_num);
+    void (*mainprog_finish_display)(void);
+    uch *image_data;
+    uch **row_pointers;
+    jmp_buf jmpbuf;
+    int passes;              /* not used */
+    int pass;
+    int rowbytes;
+    int channels;
+    int need_bgcolor;
+    int state;
+    uch bg_red;
+    uch bg_green;
+    uch bg_blue;
+} mainprog_info;
+
+
+/* prototypes for public functions in readpng2.c */
+
+void readpng2_version_info(void);
+
+int readpng2_check_sig(uch *sig, int num);
+
+int readpng2_init(mainprog_info *mainprog_ptr);
+
+int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length);
+
+void readpng2_cleanup(mainprog_info *mainprog_ptr);
diff --git a/extern/libpng/contrib/gregbook/readppm.c b/extern/libpng/contrib/gregbook/readppm.c
new file mode 100644
index 0000000000..52e7027771
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/readppm.c
@@ -0,0 +1,188 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                              readppm.c
+
+  ---------------------------------------------------------------------------
+
+   This is a special-purpose replacement for readpng.c that allows binary
+   PPM files to be used in place of PNG images.
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007,2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "readpng.h"    /* typedefs, common macros, public prototypes */
+
+
+ulg  width, height;
+int  bit_depth, color_type, channels;
+uch  *image_data = NULL;
+FILE *saved_infile;
+
+
+void readpng_version_info()
+{
+    fprintf(stderr, "   Compiled without libpng, zlib or PBMPLUS/NetPBM.\n");
+}
+
+
+/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
+
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
+{
+    static uch ppmline[256];
+    int maxval;
+
+
+    saved_infile = infile;
+
+    fgets(ppmline, 256, infile);
+    if (ppmline[0] != 'P' || ppmline[1] != '6') {
+        fprintf(stderr, "ERROR:  not a PPM file\n");
+        return 1;
+    }
+    /* possible color types:  P5 = grayscale (0), P6 = RGB (2), P8 = RGBA (6) */
+    if (ppmline[1] == '6') {
+        color_type = 2;
+        channels = 3;
+    } else if (ppmline[1] == '8') {
+        color_type = 6;
+        channels = 4;
+    } else /* if (ppmline[1] == '5') */ {
+        color_type = 0;
+        channels = 1;
+    }
+
+    do {
+        fgets(ppmline, 256, infile);
+    } while (ppmline[0] == '#');
+    sscanf(ppmline, "%lu %lu", &width, &height);
+
+    do {
+        fgets(ppmline, 256, infile);
+    } while (ppmline[0] == '#');
+    sscanf(ppmline, "%d", &maxval);
+    if (maxval != 255) {
+        fprintf(stderr, "ERROR:  maxval = %d\n", maxval);
+        return 2;
+    }
+    bit_depth = 8;
+
+    *pWidth = width;
+    *pHeight = height;
+
+    return 0;
+}
+
+
+
+
+/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
+ * scales values to 8-bit if necessary */
+
+int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
+{
+    return 1;
+}
+
+
+
+
+/* display_exponent == LUT_exponent * CRT_exponent */
+
+uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
+{
+    ulg  rowbytes;
+
+
+    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
+     * transparency chunks to full alpha channel; strip 16-bit-per-sample
+     * images to 8 bits per sample; and convert grayscale to RGB[A] */
+
+    /* GRR WARNING:  grayscale needs to be expanded and channels reset! */
+
+    *pRowbytes = rowbytes = channels*width;
+    *pChannels = channels;
+
+    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
+
+    /* Guard against integer overflow */
+    if (height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n",
+        return NULL;
+    }
+
+    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
+        return NULL;
+    }
+
+    /* now we can go ahead and just read the whole image */
+
+    if (fread(image_data, 1L, rowbytes*height, saved_infile) <
+       rowbytes*height) {
+        free (image_data);
+        image_data = NULL;
+        return NULL;
+    }
+
+    return image_data;
+}
+
+
+void readpng_cleanup(int free_image_data)
+{
+    if (free_image_data && image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+}
diff --git a/extern/libpng/contrib/gregbook/rpng-win.c b/extern/libpng/contrib/gregbook/rpng-win.c
new file mode 100644
index 0000000000..1a6f876154
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/rpng-win.c
@@ -0,0 +1,735 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                             rpng-win.c
+
+   This program decodes and displays PNG images, with gamma correction and
+   optionally with a user-specified background color (in case the image has
+   transparency).  It is very nearly the most basic PNG viewer possible.
+   This version is for 32-bit Windows; it may compile under 16-bit Windows
+   with a little tweaking (or maybe not).
+
+   to do:
+    - handle quoted command-line args (especially filenames with spaces)
+    - have minimum window width:  oh well
+    - use %.1023s to simplify truncation of title-bar string?
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.00:  initial public release
+    - 1.01:  modified to allow abbreviated options; fixed long/ulong mis-
+              match; switched to png_jmpbuf() macro
+    - 1.02:  added extra set of parentheses to png_jmpbuf() macro; fixed
+              command-line parsing bug
+    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed improper display of usage screen on PNG error(s)
+    - 2.02:  check for integer overflow (Glenn R-P)
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng-win"
+#define LONGNAME  "Simple PNG Viewer for Windows"
+#define VERSION   "2.01 of 16 March 2008"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <windows.h>
+#ifdef __CYGWIN__
+/* getch replacement. Turns out, we don't really need this,
+ * but leave it here if we ever enable any of the uses of
+ * _getch in the main code
+ */
+#include <unistd.h>
+#include <termio.h>
+#include <sys/ioctl.h>
+int repl_getch( void )
+{
+  char ch;
+  int fd = fileno(stdin);
+  struct termio old_tty, new_tty;
+
+  ioctl(fd, TCGETA, &old_tty);
+  new_tty = old_tty;
+  new_tty.c_lflag &= ~(ICANON | ECHO | ISIG);
+  ioctl(fd, TCSETA, &new_tty);
+  fread(&ch, 1, sizeof(ch), stdin);
+  ioctl(fd, TCSETA, &old_tty);
+
+  return ch;
+}
+#define _getch repl_getch
+#else
+#include <conio.h>      /* only for _getch() */
+#endif
+
+/* #define DEBUG  :  this enables the Trace() macros */
+
+#include "readpng.h"    /* typedefs, common macros, readpng prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+/* local prototypes */
+static int        rpng_win_create_window(HINSTANCE hInst, int showmode);
+static int        rpng_win_display_image(void);
+static void       rpng_win_cleanup(void);
+LRESULT CALLBACK  rpng_win_wndproc(HWND, UINT, WPARAM, LPARAM);
+
+
+static char titlebar[1024];
+static char *progname = PROGNAME;
+static char *appname = LONGNAME;
+static char *filename;
+static FILE *infile;
+
+static char *bgstr;
+static uch bg_red=0, bg_green=0, bg_blue=0;
+
+static double display_exponent;
+
+static ulg image_width, image_height, image_rowbytes;
+static int image_channels;
+static uch *image_data;
+
+/* Windows-specific variables */
+static ulg wimage_rowbytes;
+static uch *dib;
+static uch *wimage_data;
+static BITMAPINFOHEADER *bmih;
+
+static HWND global_hwnd;
+
+
+
+
+int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
+{
+    char *args[1024];                 /* arbitrary limit, but should suffice */
+    char *p, *q, **argv = args;
+    int argc = 0;
+    int rc, alen, flen;
+    int error = 0;
+    int have_bg = FALSE;
+    double LUT_exponent;              /* just the lookup table */
+    double CRT_exponent = 2.2;        /* just the monitor */
+    double default_display_exponent;  /* whole display system */
+    MSG msg;
+
+
+    filename = (char *)NULL;
+
+#ifndef __CYGWIN__
+    /* First reenable console output, which normally goes to the bit bucket
+     * for windowed apps.  Closing the console window will terminate the
+     * app.  Thanks to David.Geldreich at realviz.com for supplying the magical
+     * incantation. */
+
+    AllocConsole();
+    freopen("CONOUT$", "a", stderr);
+    freopen("CONOUT$", "a", stdout);
+#endif
+
+
+    /* Next set the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities.  And
+     * yes, these ifdefs are completely wasted in a Windows program... */
+
+#if defined(NeXT)
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to get the
+     * "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        display_exponent = atof(p);
+    else
+        display_exponent = default_display_exponent;
+
+
+    /* Windows really hates command lines, so we have to set up our own argv.
+     * Note that we do NOT bother with quoted arguments here, so don't use
+     * filenames with spaces in 'em! */
+
+    argv[argc++] = PROGNAME;
+    p = cmd;
+    for (;;) {
+        if (*p == ' ')
+            while (*++p == ' ')
+                ;
+        /* now p points at the first non-space after some spaces */
+        if (*p == '\0')
+            break;    /* nothing after the spaces:  done */
+        argv[argc++] = q = p;
+        while (*q && *q != ' ')
+            ++q;
+        /* now q points at a space or the end of the string */
+        if (*q == '\0')
+            break;    /* last argv already terminated; quit */
+        *q = '\0';    /* change space to terminator */
+        p = q + 1;
+    }
+    argv[argc] = NULL;   /* terminate the argv array itself */
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                display_exponent = atof(*argv);
+                if (display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else
+                    have_bg = TRUE;
+            }
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename)
+        ++error;
+
+
+    /* print usage screen if any errors up to this point */
+
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+
+        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
+        readpng_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-gamma exp] [-bgcolor bg] file.png\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images\n"
+          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
+#ifndef __CYGWIN__
+          "Press Q or Esc to quit this usage screen.\n"
+#endif
+          "\n", PROGNAME, default_display_exponent);
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(1);
+    }
+
+
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
+            switch (rc) {
+                case 1:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] is not a PNG file: incorrect signature\n",
+                      filename);
+                    break;
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng_init() error\n");
+                    break;
+            }
+            ++error;
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(2);
+    } else {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+#ifndef __CYGWIN__
+        fprintf(stderr,
+          "\n   [console window:  closing this window will terminate %s]\n\n",
+          PROGNAME);
+#endif
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* if the user didn't specify a background color on the command line,
+     * check for one in the PNG file--if not, the initialized values of 0
+     * (black) will be used */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        bg_red   = (uch)r;
+        bg_green = (uch)g;
+        bg_blue  = (uch)b;
+    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
+        readpng_cleanup(TRUE);
+        fprintf(stderr, PROGNAME
+          ":  libpng error while checking for background color\n");
+        exit(2);
+    }
+
+
+    /* do the basic Windows initialization stuff, make the window and fill it
+     * with the background color */
+
+    if (rpng_win_create_window(hInst, showmode))
+        exit(2);
+
+
+    /* decode the image, all at once */
+
+    Trace((stderr, "calling readpng_get_image()\n"))
+    image_data = readpng_get_image(display_exponent, &image_channels,
+      &image_rowbytes);
+    Trace((stderr, "done with readpng_get_image()\n"))
+
+
+    /* done with PNG file, so clean up to minimize memory usage (but do NOT
+     * nuke image_data!) */
+
+    readpng_cleanup(FALSE);
+    fclose(infile);
+
+    if (!image_data) {
+        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
+        exit(3);
+    }
+
+
+    /* display image (composite with background if requested) */
+
+    Trace((stderr, "calling rpng_win_display_image()\n"))
+    if (rpng_win_display_image()) {
+        free(image_data);
+        exit(4);
+    }
+    Trace((stderr, "done with rpng_win_display_image()\n"))
+
+
+    /* wait for the user to tell us when to quit */
+
+    printf(
+#ifndef __CYGWIN__
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n"
+#else
+      "Done.  Press mouse button 1 (within image window) to quit.\n"
+#endif
+    );
+    fflush(stdout);
+
+    while (GetMessage(&msg, NULL, 0, 0)) {
+        TranslateMessage(&msg);
+        DispatchMessage(&msg);
+    }
+
+
+    /* OK, we're done:  clean up all image and Windows resources and go away */
+
+    rpng_win_cleanup();
+
+    return msg.wParam;
+}
+
+
+
+
+
+static int rpng_win_create_window(HINSTANCE hInst, int showmode)
+{
+    uch *dest;
+    int extra_width, extra_height;
+    ulg i, j;
+    WNDCLASSEX wndclass;
+
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the display-specific version of the image (round up
+    to multiple of 4 for Windows DIB).
+  ---------------------------------------------------------------------------*/
+
+    wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;
+
+    /* Guard against integer overflow */
+    if (image_height > ((size_t)(-1))/wimage_rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n");
+        return 4;   /* fail */
+    }
+
+    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
+                              wimage_rowbytes*image_height)))
+    {
+        return 4;   /* fail */
+    }
+
+/*---------------------------------------------------------------------------
+    Initialize the DIB.  Negative height means to use top-down BMP ordering
+    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
+    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
+    directly => wimage_data begins immediately after BMP header.
+  ---------------------------------------------------------------------------*/
+
+    memset(dib, 0, sizeof(BITMAPINFOHEADER));
+    bmih = (BITMAPINFOHEADER *)dib;
+    bmih->biSize = sizeof(BITMAPINFOHEADER);
+    bmih->biWidth = image_width;
+    bmih->biHeight = -((long)image_height);
+    bmih->biPlanes = 1;
+    bmih->biBitCount = 24;
+    bmih->biCompression = 0;
+    wimage_data = dib + sizeof(BITMAPINFOHEADER);
+
+/*---------------------------------------------------------------------------
+    Fill in background color (black by default); data are in BGR order.
+  ---------------------------------------------------------------------------*/
+
+    for (j = 0;  j < image_height;  ++j) {
+        dest = wimage_data + j*wimage_rowbytes;
+        for (i = image_width;  i > 0;  --i) {
+            *dest++ = bg_blue;
+            *dest++ = bg_green;
+            *dest++ = bg_red;
+        }
+    }
+
+/*---------------------------------------------------------------------------
+    Set the window parameters.
+  ---------------------------------------------------------------------------*/
+
+    memset(&wndclass, 0, sizeof(wndclass));
+
+    wndclass.cbSize = sizeof(wndclass);
+    wndclass.style = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc = rpng_win_wndproc;
+    wndclass.hInstance = hInst;
+    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
+    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
+    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
+    wndclass.lpszMenuName = NULL;
+    wndclass.lpszClassName = progname;
+    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
+
+    RegisterClassEx(&wndclass);
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
+                      GetSystemMetrics(SM_CXDLGFRAME));
+    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
+                      GetSystemMetrics(SM_CYDLGFRAME)) +
+                      GetSystemMetrics(SM_CYCAPTION);
+
+    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
+      CW_USEDEFAULT, CW_USEDEFAULT, image_width+extra_width,
+      image_height+extra_height, NULL, NULL, hInst, NULL);
+
+    ShowWindow(global_hwnd, showmode);
+    UpdateWindow(global_hwnd);
+
+    return 0;
+
+} /* end function rpng_win_create_window() */
+
+
+
+
+
+static int rpng_win_display_image()
+{
+    uch *src, *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow;
+    RECT rect;
+
+
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      image_channels))
+    Trace((stderr, "(width = %ld, rowbytes = %ld, wimage_rowbytes = %d)\n",
+      image_width, image_rowbytes, wimage_rowbytes))
+
+
+/*---------------------------------------------------------------------------
+    Blast image data to buffer.  This whole routine takes place before the
+    message loop begins, so there's no real point in any pseudo-progressive
+    display...
+  ---------------------------------------------------------------------------*/
+
+    for (lastrow = row = 0;  row < image_height;  ++row) {
+        src = image_data + row*image_rowbytes;
+        dest = wimage_data + row*wimage_rowbytes;
+        if (image_channels == 3) {
+            for (i = image_width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dest++ = b;
+                *dest++ = g;   /* note reverse order */
+                *dest++ = r;
+            }
+        } else /* if (image_channels == 4) */ {
+            for (i = image_width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (a == 255) {
+                    *dest++ = b;
+                    *dest++ = g;
+                    *dest++ = r;
+                } else if (a == 0) {
+                    *dest++ = bg_blue;
+                    *dest++ = bg_green;
+                    *dest++ = bg_red;
+                } else {
+                    /* this macro (copied from png.h) composites the
+                     * foreground and background values and puts the
+                     * result into the first argument; there are no
+                     * side effects with the first argument */
+                    alpha_composite(*dest++, b, a, bg_blue);
+                    alpha_composite(*dest++, g, a, bg_green);
+                    alpha_composite(*dest++, r, a, bg_red);
+                }
+            }
+        }
+        /* display after every 16 lines */
+        if (((row+1) & 0xf) == 0) {
+            rect.left = 0L;
+            rect.top = (LONG)lastrow;
+            rect.right = (LONG)image_width;      /* possibly off by one? */
+            rect.bottom = (LONG)lastrow + 16L;   /* possibly off by one? */
+            InvalidateRect(global_hwnd, &rect, FALSE);
+            UpdateWindow(global_hwnd);     /* similar to XFlush() */
+            lastrow = row + 1;
+        }
+    }
+
+    Trace((stderr, "calling final image-flush routine\n"))
+    if (lastrow < image_height) {
+        rect.left = 0L;
+        rect.top = (LONG)lastrow;
+        rect.right = (LONG)image_width;      /* possibly off by one? */
+        rect.bottom = (LONG)image_height;    /* possibly off by one? */
+        InvalidateRect(global_hwnd, &rect, FALSE);
+        UpdateWindow(global_hwnd);     /* similar to XFlush() */
+    }
+
+/*
+    last param determines whether or not background is wiped before paint
+    InvalidateRect(global_hwnd, NULL, TRUE);
+    UpdateWindow(global_hwnd);
+ */
+
+    return 0;
+}
+
+
+
+
+
+static void rpng_win_cleanup()
+{
+    if (image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+
+    if (dib) {
+        free(dib);
+        dib = NULL;
+    }
+}
+
+
+
+
+
+LRESULT CALLBACK rpng_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
+{
+    HDC         hdc;
+    PAINTSTRUCT ps;
+    int rc;
+
+    switch (iMsg) {
+        case WM_CREATE:
+            /* one-time processing here, if any */
+            return 0;
+
+        case WM_PAINT:
+            hdc = BeginPaint(hwnd, &ps);
+                    /*                    dest                          */
+            rc = StretchDIBits(hdc, 0, 0, image_width, image_height,
+                    /*                    source                        */
+                                    0, 0, image_width, image_height,
+                                    wimage_data, (BITMAPINFO *)bmih,
+                    /*              iUsage: no clue                     */
+                                    0, SRCCOPY);
+            EndPaint(hwnd, &ps);
+            return 0;
+
+        /* wait for the user to tell us when to quit */
+        case WM_CHAR:
+            switch (wP) {      /* only need one, so ignore repeat count */
+                case 'q':
+                case 'Q':
+                case 0x1B:     /* Esc key */
+                    PostQuitMessage(0);
+            }
+            return 0;
+
+        case WM_LBUTTONDOWN:   /* another way of quitting */
+        case WM_DESTROY:
+            PostQuitMessage(0);
+            return 0;
+    }
+
+    return DefWindowProc(hwnd, iMsg, wP, lP);
+}
diff --git a/extern/libpng/contrib/gregbook/rpng-x.c b/extern/libpng/contrib/gregbook/rpng-x.c
new file mode 100644
index 0000000000..92effaa6d2
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/rpng-x.c
@@ -0,0 +1,911 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                               rpng-x.c
+
+   This program decodes and displays PNG images, with gamma correction and
+   optionally with a user-specified background color (in case the image has
+   transparency).  It is very nearly the most basic PNG viewer possible.
+   This version is for the X Window System (tested by author under Unix and
+   by Martin Zinser under OpenVMS; may work under OS/2 with some tweaking).
+
+   to do:
+    - 8-bit (colormapped) X support
+    - use %.1023s to simplify truncation of title-bar string?
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options; fixed long/ulong mis-
+              match; switched to png_jmpbuf() macro
+    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
+    - 1.11:  added extra set of parentheses to png_jmpbuf() macro; fixed
+              command-line parsing bug
+    - 1.12:  fixed some small X memory leaks (thanks to Fran�ois Petitjean)
+    - 1.13:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
+    - 1.14:  added support for X resources (thanks to Gerhard Niklasch)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed improper display of usage screen on PNG error(s)
+    - 2.02:  Added "void(argc);" statement to quiet pedantic compiler warnings
+             about unused variable (GR-P)
+    - 2.03:  check for integer overflow (Glenn R-P)
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng-x"
+#define LONGNAME  "Simple PNG Viewer for X"
+#define VERSION   "2.02 of 15 June 2014"
+#define RESNAME   "rpng"        /* our X resource application name */
+#define RESCLASS  "Rpng"        /* our X resource class name */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xos.h>
+#include <X11/keysym.h>
+
+/* #define DEBUG  :  this enables the Trace() macros */
+
+#include "readpng.h"   /* typedefs, common macros, readpng prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+/* local prototypes */
+static int  rpng_x_create_window(void);
+static int  rpng_x_display_image(void);
+static void rpng_x_cleanup(void);
+static int  rpng_x_msb(ulg u32val);
+
+
+static char titlebar[1024], *window_name = titlebar;
+static char *appname = LONGNAME;
+static char *icon_name = PROGNAME;
+static char *res_name = RESNAME;
+static char *res_class = RESCLASS;
+static char *filename;
+static FILE *infile;
+
+static char *bgstr;
+static uch bg_red=0, bg_green=0, bg_blue=0;
+
+static double display_exponent;
+
+static ulg image_width, image_height, image_rowbytes;
+static int image_channels;
+static uch *image_data;
+
+/* X-specific variables */
+static char *displayname;
+static XImage *ximage;
+static Display *display;
+static int depth;
+static Visual *visual;
+static XVisualInfo *visual_list;
+static int RShift, GShift, BShift;
+static ulg RMask, GMask, BMask;
+static Window window;
+static GC gc;
+static Colormap colormap;
+
+static int have_nondefault_visual = FALSE;
+static int have_colormap = FALSE;
+static int have_window = FALSE;
+static int have_gc = FALSE;
+/*
+ulg numcolors=0, pixels[256];
+ush reds[256], greens[256], blues[256];
+ */
+
+
+
+
+int main(int argc, char **argv)
+{
+#ifdef sgi
+    char tmpline[80];
+#endif
+    char *p;
+    int rc, alen, flen;
+    int error = 0;
+    int have_bg = FALSE;
+    double LUT_exponent;               /* just the lookup table */
+    double CRT_exponent = 2.2;         /* just the monitor */
+    double default_display_exponent;   /* whole display system */
+    XEvent e;
+    KeySym k;
+
+
+    displayname = (char *)NULL;
+    filename = (char *)NULL;
+
+
+    /* First set the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities. */
+
+#if defined(NeXT)
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to get the
+     * "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        display_exponent = atof(p);
+    else
+        display_exponent = default_display_exponent;
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-display", 2)) {
+            if (!*++argv)
+                ++error;
+            else
+                displayname = *argv;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                display_exponent = atof(*argv);
+                if (display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else
+                    have_bg = TRUE;
+            }
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename)
+        ++error;
+
+
+    /* print usage screen if any errors up to this point */
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+        readpng_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg] file.png\n"
+          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n",
+          PROGNAME, default_display_exponent);
+
+        fprintf(stderr, "\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images\n"
+          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
+          "is displayed) to quit.\n");
+        exit(1);
+    }
+
+
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
+            switch (rc) {
+                case 1:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] is not a PNG file: incorrect signature\n",
+                      filename);
+                    break;
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng_init() error\n");
+                    break;
+            }
+            ++error;
+        } else {
+            display = XOpenDisplay(displayname);
+            if (!display) {
+                readpng_cleanup(TRUE);
+                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
+                  displayname? displayname : "default");
+                ++error;
+            }
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    if (error) {
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+        exit(2);
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* if the user didn't specify a background color on the command line,
+     * check for one in the PNG file--if not, the initialized values of 0
+     * (black) will be used */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        bg_red   = (uch)r;
+        bg_green = (uch)g;
+        bg_blue  = (uch)b;
+    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
+        readpng_cleanup(TRUE);
+        fprintf(stderr, PROGNAME
+          ":  libpng error while checking for background color\n");
+        exit(2);
+    }
+
+
+    /* do the basic X initialization stuff, make the window and fill it
+     * with the background color */
+
+    if (rpng_x_create_window())
+        exit(2);
+
+
+    /* decode the image, all at once */
+
+    Trace((stderr, "calling readpng_get_image()\n"))
+    image_data = readpng_get_image(display_exponent, &image_channels,
+      &image_rowbytes);
+    Trace((stderr, "done with readpng_get_image()\n"))
+
+
+    /* done with PNG file, so clean up to minimize memory usage (but do NOT
+     * nuke image_data!) */
+
+    readpng_cleanup(FALSE);
+    fclose(infile);
+
+    if (!image_data) {
+        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
+        exit(3);
+    }
+
+
+    /* display image (composite with background if requested) */
+
+    Trace((stderr, "calling rpng_x_display_image()\n"))
+    if (rpng_x_display_image()) {
+        free(image_data);
+        exit(4);
+    }
+    Trace((stderr, "done with rpng_x_display_image()\n"))
+
+
+    /* wait for the user to tell us when to quit */
+
+    printf(
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
+    fflush(stdout);
+
+    do
+        XNextEvent(display, &e);
+    while (!(e.type == ButtonPress && e.xbutton.button == Button1) &&
+           !(e.type == KeyPress &&    /*  v--- or 1 for shifted keys */
+             ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape) ));
+
+
+    /* OK, we're done:  clean up all image and X resources and go away */
+
+    rpng_x_cleanup();
+
+    (void)argc; /* Unused */
+
+    return 0;
+}
+
+
+
+
+
+static int rpng_x_create_window(void)
+{
+    uch *xdata;
+    int need_colormap = FALSE;
+    int screen, pad;
+    ulg bg_pixel = 0L;
+    ulg attrmask;
+    Window root;
+    XEvent e;
+    XGCValues gcvalues;
+    XSetWindowAttributes attr;
+    XTextProperty windowName, *pWindowName = &windowName;
+    XTextProperty iconName, *pIconName = &iconName;
+    XVisualInfo visual_info;
+    XSizeHints *size_hints;
+    XWMHints *wm_hints;
+    XClassHint *class_hints;
+
+
+    screen = DefaultScreen(display);
+    depth = DisplayPlanes(display, screen);
+    root = RootWindow(display, screen);
+
+#ifdef DEBUG
+    XSynchronize(display, True);
+#endif
+
+#if 0
+/* GRR:  add 8-bit support */
+    if (/* depth != 8 && */ depth != 16 && depth != 24 && depth != 32) {
+        fprintf(stderr,
+          "screen depth %d not supported (only 16-, 24- or 32-bit TrueColor)\n",
+          depth);
+        return 2;
+    }
+
+    XMatchVisualInfo(display, screen, depth,
+      (depth == 8)? PseudoColor : TrueColor, &visual_info);
+    visual = visual_info.visual;
+#else
+    if (depth != 16 && depth != 24 && depth != 32) {
+        int visuals_matched = 0;
+
+        Trace((stderr, "default depth is %d:  checking other visuals\n",
+          depth))
+
+        /* 24-bit first */
+        visual_info.screen = screen;
+        visual_info.depth = 24;
+        visual_list = XGetVisualInfo(display,
+          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
+        if (visuals_matched == 0) {
+/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
+            fprintf(stderr, "default screen depth %d not supported, and no"
+              " 24-bit visuals found\n", depth);
+            return 2;
+        }
+        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
+          visuals_matched))
+        visual = visual_list[0].visual;
+        depth = visual_list[0].depth;
+/*
+        colormap_size = visual_list[0].colormap_size;
+        visual_class = visual->class;
+        visualID = XVisualIDFromVisual(visual);
+ */
+        have_nondefault_visual = TRUE;
+        need_colormap = TRUE;
+    } else {
+        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
+        visual = visual_info.visual;
+    }
+#endif
+
+    RMask = visual->red_mask;
+    GMask = visual->green_mask;
+    BMask = visual->blue_mask;
+
+/* GRR:  add/check 8-bit support */
+    if (depth == 8 || need_colormap) {
+        colormap = XCreateColormap(display, root, visual, AllocNone);
+        if (!colormap) {
+            fprintf(stderr, "XCreateColormap() failed\n");
+            return 2;
+        }
+        have_colormap = TRUE;
+    }
+    if (depth == 15 || depth == 16) {
+        RShift = 15 - rpng_x_msb(RMask);    /* these are right-shifts */
+        GShift = 15 - rpng_x_msb(GMask);
+        BShift = 15 - rpng_x_msb(BMask);
+    } else if (depth > 16) {
+#define NO_24BIT_MASKS
+#ifdef NO_24BIT_MASKS
+        RShift = rpng_x_msb(RMask) - 7;     /* these are left-shifts */
+        GShift = rpng_x_msb(GMask) - 7;
+        BShift = rpng_x_msb(BMask) - 7;
+#else
+        RShift = 7 - rpng_x_msb(RMask);     /* these are right-shifts, too */
+        GShift = 7 - rpng_x_msb(GMask);
+        BShift = 7 - rpng_x_msb(BMask);
+#endif
+    }
+    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
+        fprintf(stderr, "rpng internal logic error:  negative X shift(s)!\n");
+        return 2;
+    }
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    attr.backing_store = Always;
+    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
+    attrmask = CWBackingStore | CWEventMask;
+    if (have_nondefault_visual) {
+        attr.colormap = colormap;
+        attr.background_pixel = 0;
+        attr.border_pixel = 1;
+        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
+    }
+
+    window = XCreateWindow(display, root, 0, 0, image_width, image_height, 0,
+      depth, InputOutput, visual, attrmask, &attr);
+
+    if (window == None) {
+        fprintf(stderr, "XCreateWindow() failed\n");
+        return 2;
+    } else
+        have_window = TRUE;
+
+    if (depth == 8)
+        XSetWindowColormap(display, window, colormap);
+
+    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
+        pWindowName = NULL;
+    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
+        pIconName = NULL;
+
+    /* OK if any hints allocation fails; XSetWMProperties() allows NULLs */
+
+    if ((size_hints = XAllocSizeHints()) != NULL) {
+        /* window will not be resizable */
+        size_hints->flags = PMinSize | PMaxSize;
+        size_hints->min_width = size_hints->max_width = (int)image_width;
+        size_hints->min_height = size_hints->max_height = (int)image_height;
+    }
+
+    if ((wm_hints = XAllocWMHints()) != NULL) {
+        wm_hints->initial_state = NormalState;
+        wm_hints->input = True;
+     /* wm_hints->icon_pixmap = icon_pixmap; */
+        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
+    }
+
+    if ((class_hints = XAllocClassHint()) != NULL) {
+        class_hints->res_name = res_name;
+        class_hints->res_class = res_class;
+    }
+
+    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
+      size_hints, wm_hints, class_hints);
+
+    /* various properties and hints no longer needed; free memory */
+    if (pWindowName)
+       XFree(pWindowName->value);
+    if (pIconName)
+       XFree(pIconName->value);
+    if (size_hints)
+        XFree(size_hints);
+    if (wm_hints)
+       XFree(wm_hints);
+    if (class_hints)
+       XFree(class_hints);
+
+    XMapWindow(display, window);
+
+    gc = XCreateGC(display, window, 0, &gcvalues);
+    have_gc = TRUE;
+
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        bg_pixel = ((ulg)bg_red   << RShift) |
+                   ((ulg)bg_green << GShift) |
+                   ((ulg)bg_blue  << BShift);
+    } else if (depth == 16) {
+        bg_pixel = ((((ulg)bg_red   << 8) >> RShift) & RMask) |
+                   ((((ulg)bg_green << 8) >> GShift) & GMask) |
+                   ((((ulg)bg_blue  << 8) >> BShift) & BMask);
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    XSetForeground(display, gc, bg_pixel);
+    XFillRectangle(display, window, gc, 0, 0, image_width, image_height);
+
+/*---------------------------------------------------------------------------
+    Wait for first Expose event to do any drawing, then flush.
+  ---------------------------------------------------------------------------*/
+
+    do
+        XNextEvent(display, &e);
+    while (e.type != Expose || e.xexpose.count);
+
+    XFlush(display);
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the X- and display-specific version of the image.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        xdata = (uch *)malloc(4*image_width*image_height);
+        pad = 32;
+    } else if (depth == 16) {
+        xdata = (uch *)malloc(2*image_width*image_height);
+        pad = 16;
+    } else /* depth == 8 */ {
+        xdata = (uch *)malloc(image_width*image_height);
+        pad = 8;
+    }
+
+    if (!xdata) {
+        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
+        return 4;
+    }
+
+    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
+      (char *)xdata, image_width, image_height, pad, 0);
+
+    if (!ximage) {
+        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
+        free(xdata);
+        return 3;
+    }
+
+    /* to avoid testing the byte order every pixel (or doubling the size of
+     * the drawing routine with a giant if-test), we arbitrarily set the byte
+     * order to MSBFirst and let Xlib worry about inverting things on little-
+     * endian machines (like Linux/x86, old VAXen, etc.)--this is not the most
+     * efficient approach (the giant if-test would be better), but in the
+     * interest of clarity, we take the easy way out... */
+
+    ximage->byte_order = MSBFirst;
+
+    return 0;
+
+} /* end function rpng_x_create_window() */
+
+
+
+
+
+static int rpng_x_display_image(void)
+{
+    uch *src;
+    char *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow = 0;
+    ulg pixel;
+    int ximage_rowbytes = ximage->bytes_per_line;
+/*  int bpp = ximage->bits_per_pixel;  */
+
+
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      image_channels))
+    Trace((stderr, "   (width = %ld, rowbytes = %ld, ximage_rowbytes = %d)\n",
+      image_width, image_rowbytes, ximage_rowbytes))
+    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
+    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
+      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+
+        for (lastrow = row = 0;  row < image_height;  ++row) {
+            src = image_data + row*image_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (image_channels == 3) {
+                for (i = image_width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    /* GRR BUG:  this assumes bpp == 32, but may be 24: */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+#endif
+                }
+            } else /* if (image_channels == 4) */ {
+                for (i = image_width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (a == 255) {
+                        red   = r;
+                        green = g;
+                        blue  = b;
+                    } else if (a == 0) {
+                        red   = bg_red;
+                        green = bg_green;
+                        blue  = bg_blue;
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result into the
+                         * first argument */
+                        alpha_composite(red,   r, a, bg_red);
+                        alpha_composite(green, g, a, bg_green);
+                        alpha_composite(blue,  b, a, bg_blue);
+                    }
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, image_width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        for (lastrow = row = 0;  row < image_height;  ++row) {
+            src = image_data + row*image_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (image_channels == 3) {
+                for (i = image_width;  i > 0;  --i) {
+                    red   = ((ush)(*src) << 8);
+                    ++src;
+                    green = ((ush)(*src) << 8);
+                    ++src;
+                    blue  = ((ush)(*src) << 8);
+                    ++src;
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else /* if (image_channels == 4) */ {
+                for (i = image_width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (a == 255) {
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    } else if (a == 0) {
+                        red   = ((ush)bg_red   << 8);
+                        green = ((ush)bg_green << 8);
+                        blue  = ((ush)bg_blue  << 8);
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result back into
+                         * the first argument (== fg byte here:  safe) */
+                        alpha_composite(r, r, a, bg_red);
+                        alpha_composite(g, g, a, bg_green);
+                        alpha_composite(b, b, a, bg_blue);
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    }
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, image_width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    Trace((stderr, "calling final XPutImage()\n"))
+    if (lastrow < image_height) {
+        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+          (int)lastrow, image_width, image_height-lastrow);
+        XFlush(display);
+    }
+
+    return 0;
+}
+
+
+
+
+static void rpng_x_cleanup(void)
+{
+    if (image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+
+    if (ximage) {
+        if (ximage->data) {
+            free(ximage->data);           /* we allocated it, so we free it */
+            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
+        }
+        XDestroyImage(ximage);
+        ximage = NULL;
+    }
+
+    if (have_gc)
+        XFreeGC(display, gc);
+
+    if (have_window)
+        XDestroyWindow(display, window);
+
+    if (have_colormap)
+        XFreeColormap(display, colormap);
+
+    if (have_nondefault_visual)
+        XFree(visual_list);
+}
+
+
+
+
+
+static int rpng_x_msb(ulg u32val)
+{
+    int i;
+
+    for (i = 31;  i >= 0;  --i) {
+        if (u32val & 0x80000000L)
+            break;
+        u32val <<= 1;
+    }
+    return i;
+}
diff --git a/extern/libpng/contrib/gregbook/rpng2-win.c b/extern/libpng/contrib/gregbook/rpng2-win.c
new file mode 100644
index 0000000000..ed6b526ecb
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/rpng2-win.c
@@ -0,0 +1,1261 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                rpng2-win.c
+
+   This program decodes and displays PNG files progressively, as if it were
+   a web browser (though the front end is only set up to read from files).
+   It supports gamma correction, user-specified background colors, and user-
+   specified background patterns (for transparent images).  This version is
+   for 32-bit Windows; it may compile under 16-bit Windows with a little
+   tweaking (or maybe not).  Thanks to Adam Costello and Pieter S. van der
+   Meulen for the "diamond" and "radial waves" patterns, respectively.
+
+   to do (someday, maybe):
+    - handle quoted command-line args (especially filenames with spaces)
+    - finish resizable checkerboard-gradient (sizes 4-128?)
+    - use %.1023s to simplify truncation of title-bar string?
+    - have minimum window width:  oh well
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  fixed cut-and-paste error in usage screen (oops...)
+    - 1.03:  modified to allow abbreviated options
+    - 1.04:  removed bogus extra argument from usage fprintf() [Glenn R-P?];
+              fixed command-line parsing bug
+    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
+    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
+    - 1.21:  made minor tweak to usage screen to fit within 25-line console
+    - 1.22:  added AMD64/EM64T support (__x86_64__)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed 64-bit typo in readpng2.c
+    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
+              unexpected-EOF and file-read-error cases
+    - 2.03:  removed runtime MMX-enabling/disabling and obsolete -mmx* options
+    - 2.04:  check for integer overflow (Glenn R-P)
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng2-win"
+#define LONGNAME  "Progressive PNG Viewer for Windows"
+#define VERSION   "2.02 of 16 March 2008"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <setjmp.h>    /* for jmpbuf declaration in readpng2.h */
+#include <time.h>
+#include <math.h>      /* only for PvdM background code */
+#include <windows.h>
+#ifdef __CYGWIN__
+/* getch replacement. Turns out, we don't really need this,
+ * but leave it here if we ever enable any of the uses of
+ * _getch in the main code
+ */
+#include <unistd.h>
+#include <termio.h>
+#include <sys/ioctl.h>
+int repl_getch( void )
+{
+  char ch;
+  int fd = fileno(stdin);
+  struct termio old_tty, new_tty;
+
+  ioctl(fd, TCGETA, &old_tty);
+  new_tty = old_tty;
+  new_tty.c_lflag &= ~(ICANON | ECHO | ISIG);
+  ioctl(fd, TCSETA, &new_tty);
+  fread(&ch, 1, sizeof(ch), stdin);
+  ioctl(fd, TCSETA, &old_tty);
+
+  return ch;
+}
+#define _getch repl_getch
+#else
+#include <conio.h>     /* only for _getch() */
+#endif
+
+/* all for PvdM background code: */
+#ifndef PI
+#  define PI             3.141592653589793238
+#endif
+#define PI_2             (PI*0.5)
+#define INV_PI_360       (360.0 / PI)
+#define MAX(a,b)         (a>b?a:b)
+#define MIN(a,b)         (a<b?a:b)
+#define CLIP(a,min,max)  MAX(min,MIN((a),max))
+#define ABS(a)           ((a)<0?-(a):(a))
+#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
+#define ROUNDF(f)        ((int)(f + 0.5))
+
+#define rgb1_max   bg_freq
+#define rgb1_min   bg_gray
+#define rgb2_max   bg_bsat
+#define rgb2_min   bg_brot
+
+/* #define DEBUG */     /* this enables the Trace() macros */
+
+#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
+                          *  block size corresponds roughly to a download
+                          *  speed 10% faster than theoretical 33.6K maximum
+                          *  (assuming 8 data bits, 1 stop bit and no other
+                          *  overhead) */
+
+/* local prototypes */
+static void       rpng2_win_init(void);
+static int        rpng2_win_create_window(void);
+static int        rpng2_win_load_bg_image(void);
+static void       rpng2_win_display_row(ulg row);
+static void       rpng2_win_finish_display(void);
+static void       rpng2_win_cleanup(void);
+LRESULT CALLBACK  rpng2_win_wndproc(HWND, UINT, WPARAM, LPARAM);
+
+
+static char titlebar[1024];
+static char *progname = PROGNAME;
+static char *appname = LONGNAME;
+static char *filename;
+static FILE *infile;
+
+static mainprog_info rpng2_info;
+
+static uch inbuf[INBUFSIZE];
+static int incount;
+
+static int pat = 6;         /* must be less than num_bgpat */
+static int bg_image = 0;
+static int bgscale = 16;
+static ulg bg_rowbytes;
+static uch *bg_data;
+
+static struct rgb_color {
+    uch r, g, b;
+} rgb[] = {
+    {  0,   0,   0},    /*  0:  black */
+    {255, 255, 255},    /*  1:  white */
+    {173, 132,  57},    /*  2:  tan */
+    { 64, 132,   0},    /*  3:  medium green */
+    {189, 117,   1},    /*  4:  gold */
+    {253, 249,   1},    /*  5:  yellow */
+    {  0,   0, 255},    /*  6:  blue */
+    {  0,   0, 120},    /*  7:  medium blue */
+    {255,   0, 255},    /*  8:  magenta */
+    { 64,   0,  64},    /*  9:  dark magenta */
+    {255,   0,   0},    /* 10:  red */
+    { 64,   0,   0},    /* 11:  dark red */
+    {255, 127,   0},    /* 12:  orange */
+    {192,  96,   0},    /* 13:  darker orange */
+    { 24,  60,   0},    /* 14:  dark green-yellow */
+    { 85, 125, 200}     /* 15:  ice blue */
+};
+/* not used for now, but should be for error-checking:
+static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
+ */
+
+/*
+    This whole struct is a fairly cheesy way to keep the number of
+    command-line options to a minimum.  The radial-waves background
+    type is a particularly poor fit to the integer elements of the
+    struct...but a few macros and a little fixed-point math will do
+    wonders for ya.
+
+    type bits:
+       F E D C B A 9 8 7 6 5 4 3 2 1 0
+                             | | | | |
+                             | | +-+-+-- 0 = sharp-edged checkerboard
+                             | |         1 = soft diamonds
+                             | |         2 = radial waves
+                             | |       3-7 = undefined
+                             | +-- gradient #2 inverted?
+                             +-- alternating columns inverted?
+ */
+static struct background_pattern {
+    ush type;
+    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
+    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
+} bg[] = {
+    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
+    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
+    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
+    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
+    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
+    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
+    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
+    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
+    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
+    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
+    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
+    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
+    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
+    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
+    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
+    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
+};
+static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
+
+
+/* Windows-specific global variables (could go in struct, but messy...) */
+static ulg wimage_rowbytes;
+static uch *dib;
+static uch *wimage_data;
+static BITMAPINFOHEADER *bmih;
+
+static HWND global_hwnd;
+static HINSTANCE global_hInst;
+static int global_showmode;
+
+
+
+
+int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
+{
+    char *args[1024];                 /* arbitrary limit, but should suffice */
+    char **argv = args;
+    char *p, *q, *bgstr = NULL;
+    int argc = 0;
+    int rc, alen, flen;
+    int error = 0;
+    int timing = FALSE;
+    int have_bg = FALSE;
+    double LUT_exponent;              /* just the lookup table */
+    double CRT_exponent = 2.2;        /* just the monitor */
+    double default_display_exponent;  /* whole display system */
+    MSG msg;
+
+
+    /* First initialize a few things, just to be sure--memset takes care of
+     * default background color (black), booleans (FALSE), pointers (NULL),
+     * etc. */
+
+    global_hInst = hInst;
+    global_showmode = showmode;
+    filename = (char *)NULL;
+    memset(&rpng2_info, 0, sizeof(mainprog_info));
+
+#ifndef __CYGWIN__
+    /* Next reenable console output, which normally goes to the bit bucket
+     * for windowed apps.  Closing the console window will terminate the
+     * app.  Thanks to David.Geldreich at realviz.com for supplying the magical
+     * incantation. */
+
+    AllocConsole();
+    freopen("CONOUT$", "a", stderr);
+    freopen("CONOUT$", "a", stdout);
+#endif
+
+    /* Set the default value for our display-system exponent, i.e., the
+     * product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities.  And
+     * yes, these ifdefs are completely wasted in a Windows program... */
+
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        rpng2_info.display_exponent = atof(p);
+    else
+        rpng2_info.display_exponent = default_display_exponent;
+
+
+    /* Windows really hates command lines, so we have to set up our own argv.
+     * Note that we do NOT bother with quoted arguments here, so don't use
+     * filenames with spaces in 'em! */
+
+    argv[argc++] = PROGNAME;
+    p = cmd;
+    for (;;) {
+        if (*p == ' ')
+            while (*++p == ' ')
+                ;
+        /* now p points at the first non-space after some spaces */
+        if (*p == '\0')
+            break;    /* nothing after the spaces:  done */
+        argv[argc++] = q = p;
+        while (*q && *q != ' ')
+            ++q;
+        /* now q points at a space or the end of the string */
+        if (*q == '\0')
+            break;    /* last argv already terminated; quit */
+        *q = '\0';    /* change space to terminator */
+        p = q + 1;
+    }
+    argv[argc] = NULL;   /* terminate the argv array itself */
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                rpng2_info.display_exponent = atof(*argv);
+                if (rpng2_info.display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    have_bg = TRUE;
+                    bg_image = FALSE;
+                }
+            }
+        } else if (!strncmp(*argv, "-bgpat", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                pat = atoi(*argv) - 1;
+                if (pat < 0 || pat >= num_bgpat)
+                    ++error;
+                else {
+                    bg_image = TRUE;
+                    have_bg = FALSE;
+                }
+            }
+        } else if (!strncmp(*argv, "-timing", 2)) {
+            timing = TRUE;
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename)
+        ++error;
+
+
+    /* print usage screen if any errors up to this point */
+
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+
+        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
+        readpng2_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-gamma exp] [-bgcolor bg | -bgpat pat] [-timing]\n"
+          "        %*s file.png\n\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images; overrides -bgpat option\n"
+          "    pat \tdesired background pattern number (1-%d); used with\n"
+          "\t\t  transparent images; overrides -bgcolor option\n"
+          "    -timing\tenables delay for every block read, to simulate modem\n"
+          "\t\t  download of image (~36 Kbps)\n"
+          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
+#ifndef __CYGWIN__
+          "Press Q or Esc to quit this usage screen. ",
+#else
+          ,
+#endif
+          PROGNAME,
+#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__)) && \
+    !(defined(__CYGWIN__) || defined(__MINGW32__))
+          (int)strlen(PROGNAME), " ",
+#endif
+          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat);
+        fflush(stderr);
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(1);
+    }
+
+
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
+            fprintf(stderr, PROGNAME
+              ":  [%s] is not a PNG file: incorrect signature\n",
+              filename);
+            ++error;
+        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
+            switch (rc) {
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng2_init() error\n");
+                    break;
+            }
+            ++error;
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(2);
+    } else {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+#ifndef __CYGWIN__
+        fprintf(stderr,
+          "\n   [console window:  closing this window will terminate %s]\n\n",
+          PROGNAME);
+#endif
+        fflush(stderr);
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* set some final rpng2_info variables before entering main data loop */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        rpng2_info.bg_red   = (uch)r;
+        rpng2_info.bg_green = (uch)g;
+        rpng2_info.bg_blue  = (uch)b;
+    } else
+        rpng2_info.need_bgcolor = TRUE;
+
+    rpng2_info.state = kPreInit;
+    rpng2_info.mainprog_init = rpng2_win_init;
+    rpng2_info.mainprog_display_row = rpng2_win_display_row;
+    rpng2_info.mainprog_finish_display = rpng2_win_finish_display;
+
+
+    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
+     * the loop to deal with our first buffer of data (read in above to verify
+     * that the file is a PNG image), then loop through the file and continue
+     * calling the same routine to handle each chunk of data.  It in turn
+     * passes the data to libpng, which will invoke one or more of our call-
+     * backs as decoded data become available.  We optionally call Sleep() for
+     * one second per iteration to simulate downloading the image via an analog
+     * modem. */
+
+    for (;;) {
+        Trace((stderr, "about to call readpng2_decode_data()\n"))
+        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
+            ++error;
+        Trace((stderr, "done with readpng2_decode_data()\n"))
+
+        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
+            if (rpng2_info.state == kDone) {
+                Trace((stderr, "done decoding PNG image\n"))
+            } else if (ferror(infile)) {
+                fprintf(stderr, PROGNAME
+                  ":  error while reading PNG image file\n");
+                exit(3);
+            } else if (feof(infile)) {
+                fprintf(stderr, PROGNAME ":  end of file reached "
+                  "(unexpectedly) while reading PNG image file\n");
+                exit(3);
+            } else /* if (error) */ {
+                /* will print error message below */
+            }
+            break;
+        }
+
+        if (timing)
+            Sleep(1000L);
+
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+    }
+
+
+    /* clean up PNG stuff and report any decoding errors */
+
+    fclose(infile);
+    Trace((stderr, "about to call readpng2_cleanup()\n"))
+    readpng2_cleanup(&rpng2_info);
+
+    if (error) {
+        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
+        exit(3);
+    }
+
+
+    /* wait for the user to tell us when to quit */
+
+    while (GetMessage(&msg, NULL, 0, 0)) {
+        TranslateMessage(&msg);
+        DispatchMessage(&msg);
+    }
+
+
+    /* we're done:  clean up all image and Windows resources and go away */
+
+    Trace((stderr, "about to call rpng2_win_cleanup()\n"))
+    rpng2_win_cleanup();
+
+    return msg.wParam;
+}
+
+
+
+
+
+/* this function is called by readpng2_info_callback() in readpng2.c, which
+ * in turn is called by libpng after all of the pre-IDAT chunks have been
+ * read and processed--i.e., we now have enough info to finish initializing */
+
+static void rpng2_win_init()
+{
+    ulg i;
+    ulg rowbytes = rpng2_info.rowbytes;
+
+    Trace((stderr, "beginning rpng2_win_init()\n"))
+    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
+    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
+    Trace((stderr, "  height = %ld\n", rpng2_info.height))
+
+    /* Guard against integer overflow */
+    if (rpng2_info.height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n",
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
+    if (!rpng2_info.image_data) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
+    if (!rpng2_info.row_pointers) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    for (i = 0;  i < rpng2_info.height;  ++i)
+        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
+
+/*---------------------------------------------------------------------------
+    Do the basic Windows initialization stuff, make the window, and fill it
+    with the user-specified, file-specified or default background color.
+  ---------------------------------------------------------------------------*/
+
+    if (rpng2_win_create_window()) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.state = kWindowInit;
+}
+
+
+
+
+
+static int rpng2_win_create_window()
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *dest;
+    int extra_width, extra_height;
+    ulg i, j;
+    WNDCLASSEX wndclass;
+    RECT rect;
+
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the display-specific version of the image (round up
+    to multiple of 4 for Windows DIB).
+  ---------------------------------------------------------------------------*/
+
+    wimage_rowbytes = ((3*rpng2_info.width + 3L) >> 2) << 2;
+
+    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
+                              wimage_rowbytes*rpng2_info.height)))
+    {
+        return 4;   /* fail */
+    }
+
+/*---------------------------------------------------------------------------
+    Initialize the DIB.  Negative height means to use top-down BMP ordering
+    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
+    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
+    directly => wimage_data begins immediately after BMP header.
+  ---------------------------------------------------------------------------*/
+
+    memset(dib, 0, sizeof(BITMAPINFOHEADER));
+    bmih = (BITMAPINFOHEADER *)dib;
+    bmih->biSize = sizeof(BITMAPINFOHEADER);
+    bmih->biWidth = rpng2_info.width;
+    bmih->biHeight = -((long)rpng2_info.height);
+    bmih->biPlanes = 1;
+    bmih->biBitCount = 24;
+    bmih->biCompression = 0;
+    wimage_data = dib + sizeof(BITMAPINFOHEADER);
+
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color (default is black), but
+    defer loading faked "background image" until window is displayed (may be
+    slow to compute).  Data are in BGR order.
+  ---------------------------------------------------------------------------*/
+
+    if (bg_image) {   /* just fill with black for now */
+        memset(wimage_data, 0, wimage_rowbytes*rpng2_info.height);
+    } else {
+        for (j = 0;  j < rpng2_info.height;  ++j) {
+            dest = wimage_data + j*wimage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                *dest++ = bg_blue;
+                *dest++ = bg_green;
+                *dest++ = bg_red;
+            }
+        }
+    }
+
+/*---------------------------------------------------------------------------
+    Set the window parameters.
+  ---------------------------------------------------------------------------*/
+
+    memset(&wndclass, 0, sizeof(wndclass));
+
+    wndclass.cbSize = sizeof(wndclass);
+    wndclass.style = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc = rpng2_win_wndproc;
+    wndclass.hInstance = global_hInst;
+    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
+    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
+    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
+    wndclass.lpszMenuName = NULL;
+    wndclass.lpszClassName = progname;
+    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
+
+    RegisterClassEx(&wndclass);
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
+                      GetSystemMetrics(SM_CXDLGFRAME));
+    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
+                      GetSystemMetrics(SM_CYDLGFRAME)) +
+                      GetSystemMetrics(SM_CYCAPTION);
+
+    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
+      CW_USEDEFAULT, CW_USEDEFAULT, rpng2_info.width+extra_width,
+      rpng2_info.height+extra_height, NULL, NULL, global_hInst, NULL);
+
+    ShowWindow(global_hwnd, global_showmode);
+    UpdateWindow(global_hwnd);
+
+/*---------------------------------------------------------------------------
+    Now compute the background image and display it.  If it fails (memory
+    allocation), revert to a plain background color.
+  ---------------------------------------------------------------------------*/
+
+    if (bg_image) {
+        static const char *msg = "Computing background image...";
+        int x, y, len = strlen(msg);
+        HDC hdc = GetDC(global_hwnd);
+        TEXTMETRIC tm;
+
+        GetTextMetrics(hdc, &tm);
+        x = (rpng2_info.width - len*tm.tmAveCharWidth)/2;
+        y = (rpng2_info.height - tm.tmHeight)/2;
+        SetBkMode(hdc, TRANSPARENT);
+        SetTextColor(hdc, GetSysColor(COLOR_HIGHLIGHTTEXT));
+        /* this can still begin out of bounds even if x is positive (???): */
+        TextOut(hdc, ((x < 0)? 0 : x), ((y < 0)? 0 : y), msg, len);
+        ReleaseDC(global_hwnd, hdc);
+
+        rpng2_win_load_bg_image();   /* resets bg_image if fails */
+    }
+
+    if (!bg_image) {
+        for (j = 0;  j < rpng2_info.height;  ++j) {
+            dest = wimage_data + j*wimage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                *dest++ = bg_blue;
+                *dest++ = bg_green;
+                *dest++ = bg_red;
+            }
+        }
+    }
+
+    rect.left = 0L;
+    rect.top = 0L;
+    rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
+    rect.bottom = (LONG)rpng2_info.height;     /* possibly off by one? */
+    InvalidateRect(global_hwnd, &rect, FALSE);
+    UpdateWindow(global_hwnd);                 /* similar to XFlush() */
+
+    return 0;
+
+} /* end function rpng2_win_create_window() */
+
+
+
+
+
+static int rpng2_win_load_bg_image()
+{
+    uch *src, *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max = (bgscale-1);
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    ulg i, row;
+
+/*---------------------------------------------------------------------------
+    Allocate buffer for fake background image to be used with transparent
+    images; if this fails, revert to plain background color.
+  ---------------------------------------------------------------------------*/
+
+    bg_rowbytes = 3 * rpng2_info.width;
+    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
+    if (!bg_data) {
+        fprintf(stderr, PROGNAME
+          ":  unable to allocate memory for background image\n");
+        bg_image = 0;
+        return 1;
+    }
+
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = row % bgscale;
+            even_odd_vert = (row / bgscale) & 1;
+
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (i / bgscale) & 1;
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {         /* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {                     /* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;        /* not inverted or */
+                        *dest++ = g2;        /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;    /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 1) {
+
+        hmax = (bgscale-1)/2;   /* half the max weight of a color */
+        max = 2*hmax;           /* the max weight of a color */
+
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = row % bgscale;
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = i % bgscale;
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+
+        fprintf(stderr, "%s:  computing radial background...",
+          PROGNAME);
+        fflush(stderr);
+
+        hh = rpng2_info.height / 2;
+        hw = rpng2_info.width / 2;
+
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = row - hh;
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = i - hw;
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+        fprintf(stderr, "done.\n");
+        fflush(stderr);
+    }
+
+/*---------------------------------------------------------------------------
+    Blast background image to display buffer before beginning PNG decode;
+    calling function will handle invalidation and UpdateWindow() call.
+  ---------------------------------------------------------------------------*/
+
+    for (row = 0;  row < rpng2_info.height;  ++row) {
+        src = bg_data + row*bg_rowbytes;
+        dest = wimage_data + row*wimage_rowbytes;
+        for (i = rpng2_info.width;  i > 0;  --i) {
+            r1 = *src++;
+            g1 = *src++;
+            b1 = *src++;
+            *dest++ = b1;
+            *dest++ = g1;   /* note reverse order */
+            *dest++ = r1;
+        }
+    }
+
+    return 0;
+
+} /* end function rpng2_win_load_bg_image() */
+
+
+
+
+
+static void rpng2_win_display_row(ulg row)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL, *dest;
+    uch r, g, b, a;
+    ulg i;
+    static int rows=0;
+    static ulg firstrow;
+
+/*---------------------------------------------------------------------------
+    rows and firstrow simply track how many rows (and which ones) have not
+    yet been displayed; alternatively, we could call InvalidateRect() for
+    every row and not bother with the records-keeping.
+  ---------------------------------------------------------------------------*/
+
+    Trace((stderr, "beginning rpng2_win_display_row()\n"))
+
+    if (rows == 0)
+        firstrow = row;   /* first row not yet displayed */
+
+    ++rows;   /* count of rows received but not yet displayed */
+
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct and the lack of an outer
+    loop (over rows), this routine is identical to rpng_win_display_image()
+    in the non-progressive version of the program.
+  ---------------------------------------------------------------------------*/
+
+    src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+    if (bg_image)
+        src2 = bg_data + row*bg_rowbytes;
+    dest = wimage_data + row*wimage_rowbytes;
+
+    if (rpng2_info.channels == 3) {
+        for (i = rpng2_info.width;  i > 0;  --i) {
+            r = *src++;
+            g = *src++;
+            b = *src++;
+            *dest++ = b;
+            *dest++ = g;   /* note reverse order */
+            *dest++ = r;
+        }
+    } else /* if (rpng2_info.channels == 4) */ {
+        for (i = rpng2_info.width;  i > 0;  --i) {
+            r = *src++;
+            g = *src++;
+            b = *src++;
+            a = *src++;
+            if (bg_image) {
+                bg_red   = *src2++;
+                bg_green = *src2++;
+                bg_blue  = *src2++;
+            }
+            if (a == 255) {
+                *dest++ = b;
+                *dest++ = g;
+                *dest++ = r;
+            } else if (a == 0) {
+                *dest++ = bg_blue;
+                *dest++ = bg_green;
+                *dest++ = bg_red;
+            } else {
+                /* this macro (copied from png.h) composites the
+                 * foreground and background values and puts the
+                 * result into the first argument; there are no
+                 * side effects with the first argument */
+                alpha_composite(*dest++, b, a, bg_blue);
+                alpha_composite(*dest++, g, a, bg_green);
+                alpha_composite(*dest++, r, a, bg_red);
+            }
+        }
+    }
+
+/*---------------------------------------------------------------------------
+    Display after every 16 rows or when on last row.  (Region may include
+    previously displayed lines due to interlacing--i.e., not contiguous.)
+  ---------------------------------------------------------------------------*/
+
+    if ((rows & 0xf) == 0 || row == rpng2_info.height-1) {
+        RECT rect;
+
+        rect.left = 0L;
+        rect.top = (LONG)firstrow;
+        rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
+        rect.bottom = (LONG)row + 1L;              /* possibly off by one? */
+        InvalidateRect(global_hwnd, &rect, FALSE);
+        UpdateWindow(global_hwnd);                 /* similar to XFlush() */
+        rows = 0;
+    }
+
+} /* end function rpng2_win_display_row() */
+
+
+
+
+
+static void rpng2_win_finish_display()
+{
+    Trace((stderr, "beginning rpng2_win_finish_display()\n"))
+
+    /* last row has already been displayed by rpng2_win_display_row(), so
+     * we have nothing to do here except set a flag and let the user know
+     * that the image is done */
+
+    rpng2_info.state = kDone;
+    printf(
+#ifndef __CYGWIN__
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n"
+#else
+      "Done.  Press mouse button 1 (within image window) to quit.\n"
+#endif
+    );
+    fflush(stdout);
+}
+
+
+
+
+
+static void rpng2_win_cleanup()
+{
+    if (bg_image && bg_data) {
+        free(bg_data);
+        bg_data = NULL;
+    }
+
+    if (rpng2_info.image_data) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+    }
+
+    if (rpng2_info.row_pointers) {
+        free(rpng2_info.row_pointers);
+        rpng2_info.row_pointers = NULL;
+    }
+
+    if (dib) {
+        free(dib);
+        dib = NULL;
+    }
+}
+
+
+
+
+
+LRESULT CALLBACK rpng2_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
+{
+    HDC         hdc;
+    PAINTSTRUCT ps;
+    int rc;
+
+    switch (iMsg) {
+        case WM_CREATE:
+            /* one-time processing here, if any */
+            return 0;
+
+        case WM_PAINT:
+            hdc = BeginPaint(hwnd, &ps);
+            rc = StretchDIBits(hdc, 0, 0, rpng2_info.width, rpng2_info.height,
+                                    0, 0, rpng2_info.width, rpng2_info.height,
+                                    wimage_data, (BITMAPINFO *)bmih,
+                                    0, SRCCOPY);
+            EndPaint(hwnd, &ps);
+            return 0;
+
+        /* wait for the user to tell us when to quit */
+        case WM_CHAR:
+            switch (wP) {       /* only need one, so ignore repeat count */
+                case 'q':
+                case 'Q':
+                case 0x1B:      /* Esc key */
+                    PostQuitMessage(0);
+            }
+            return 0;
+
+        case WM_LBUTTONDOWN:    /* another way of quitting */
+        case WM_DESTROY:
+            PostQuitMessage(0);
+            return 0;
+    }
+
+    return DefWindowProc(hwnd, iMsg, wP, lP);
+}
diff --git a/extern/libpng/contrib/gregbook/rpng2-x.c b/extern/libpng/contrib/gregbook/rpng2-x.c
new file mode 100644
index 0000000000..af944c0f2b
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/rpng2-x.c
@@ -0,0 +1,2143 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                  rpng2-x.c
+
+   This program decodes and displays PNG files progressively, as if it were
+   a web browser (though the front end is only set up to read from files).
+   It supports gamma correction, user-specified background colors, and user-
+   specified background patterns (for transparent images).  This version is
+   for the X Window System (tested by the author under Unix and by Martin
+   Zinser under OpenVMS; may work under OS/2 with a little tweaking).
+
+   Thanks to Adam Costello and Pieter S. van der Meulen for the "diamond"
+   and "radial waves" patterns, respectively.
+
+   to do (someday, maybe):
+    - fix expose/redraw code:  don't draw entire row if only part exposed
+    - 8-bit (colormapped) X support
+    - finish resizable checkerboard-gradient (sizes 4-128?)
+    - use %.1023s to simplify truncation of title-bar string?
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options; fixed char/uchar mismatch
+    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
+    - 1.11:  added -usleep option for demos; fixed command-line parsing bug
+    - 1.12:  added -pause option for demos and testing
+    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
+    - 1.21:  fixed some small X memory leaks (thanks to Fran�ois Petitjean)
+    - 1.22:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
+    - 1.23:  added -bgpat 0 mode (std white/gray checkerboard, 8x8 squares)
+    - 1.30:  added -loop option for -bgpat (ifdef FEATURE_LOOP); fixed bpp =
+              24; added support for X resources (thanks to Gerhard Niklasch)
+    - 1.31:  added code to skip unused chunks (thanks to Glenn Randers-Pehrson)
+    - 1.32:  added AMD64/EM64T support (__x86_64__); added basic expose/redraw
+              handling
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed 64-bit typo in readpng2.c; fixed -pause usage description
+    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
+              unexpected-EOF and file-read-error cases; fixed Trace() cut-and-
+              paste bugs
+    - 2.03:  deleted runtime MMX-enabling/disabling and obsolete -mmx* options
+    - 2.04:  Added "void(foo);" statements to quiet pedantic compiler warnings
+             about unused variables (GR-P)
+    - 2.05:  Use nanosleep() instead of usleep(), which is deprecated (GR-P).
+    - 2.06:  check for integer overflow (Glenn R-P)
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2010, 2014-2015, 2017 Greg Roelofs.  All rights
+      reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng2-x"
+#define LONGNAME  "Progressive PNG Viewer for X"
+#define VERSION   "2.04 of 15 June 2014"
+#define RESNAME   "rpng2"       /* our X resource application name */
+#define RESCLASS  "Rpng"       /* our X resource class name */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <setjmp.h>       /* for jmpbuf declaration in readpng2.h */
+#include <time.h>
+#include <math.h>         /* only for PvdM background code */
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xos.h>
+#include <X11/keysym.h>   /* defines XK_* macros */
+
+#if _POSIX_C_SOURCE >= 199309L /* have nanosleep() */
+# undef usleep
+# define usleep(usec) {        \
+   struct timespec ts;         \
+   ts.tv_sec = 0;              \
+   ts.tv_nsec = (usec) * 1000; \
+   nanosleep(&ts, NULL); }
+#  endif
+
+#ifndef usleep /* have neither nanosleep() nor usleep() */
+#  define usleep(x) sleep(((x)+499999)/1000000)
+#endif
+
+#ifdef VMS
+#  include <unistd.h>
+#endif
+
+/* all for PvdM background code: */
+#ifndef PI
+#  define PI             3.141592653589793238
+#endif
+#define PI_2             (PI*0.5)
+#define INV_PI_360       (360.0 / PI)
+#define MAX(a,b)         (a>b?a:b)
+#define MIN(a,b)         (a<b?a:b)
+#define CLIP(a,min,max)  MAX(min,MIN((a),max))
+#define ABS(a)           ((a)<0?-(a):(a))
+#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
+#define ROUNDF(f)        ((int)(f + 0.5))
+
+#define QUIT(e,k) ((e.type == ButtonPress && e.xbutton.button == Button1) ||  \
+                  (e.type == KeyPress &&   /*  v--- or 1 for shifted keys */  \
+                  ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape)))
+
+#define NO_24BIT_MASKS /* undef case not fully written--only for redisplay() */
+
+#define rgb1_max   bg_freq
+#define rgb1_min   bg_gray
+#define rgb2_max   bg_bsat
+#define rgb2_min   bg_brot
+
+/* #define DEBUG */     /* this enables the Trace() macros */
+
+#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
+                          *  block size corresponds roughly to a download
+                          *  speed 10% faster than theoretical 33.6K maximum
+                          *  (assuming 8 data bits, 1 stop bit and no other
+                          *  overhead) */
+
+/* local prototypes */
+static void rpng2_x_init (void);
+static int  rpng2_x_create_window (void);
+static int  rpng2_x_load_bg_image (void);
+static void rpng2_x_display_row (ulg row);
+static void rpng2_x_finish_display (void);
+static void rpng2_x_redisplay_image (ulg startcol, ulg startrow,
+                                     ulg width, ulg height);
+#ifdef FEATURE_LOOP
+static void rpng2_x_reload_bg_image (void);
+static int  is_number (char *p);
+#endif
+static void rpng2_x_cleanup (void);
+static int  rpng2_x_msb (ulg u32val);
+
+
+static char titlebar[1024], *window_name = titlebar;
+static char *appname = LONGNAME;
+static char *icon_name = PROGNAME;
+static char *res_name = RESNAME;
+static char *res_class = RESCLASS;
+static char *filename;
+static FILE *infile;
+
+static mainprog_info rpng2_info;
+
+static uch inbuf[INBUFSIZE];
+static int incount;
+
+static int pat = 6;        /* must be less than num_bgpat */
+static int bg_image = 0;
+static int bgscale, bgscale_default = 16;
+static ulg bg_rowbytes;
+static uch *bg_data;
+
+int pause_after_pass = FALSE;
+int demo_timing = FALSE;
+ulg usleep_duration = 0L;
+
+static struct rgb_color {
+    uch r, g, b;
+} rgb[] = {
+    {  0,   0,   0},    /*  0:  black */
+    {255, 255, 255},    /*  1:  white */
+    {173, 132,  57},    /*  2:  tan */
+    { 64, 132,   0},    /*  3:  medium green */
+    {189, 117,   1},    /*  4:  gold */
+    {253, 249,   1},    /*  5:  yellow */
+    {  0,   0, 255},    /*  6:  blue */
+    {  0,   0, 120},    /*  7:  medium blue */
+    {255,   0, 255},    /*  8:  magenta */
+    { 64,   0,  64},    /*  9:  dark magenta */
+    {255,   0,   0},    /* 10:  red */
+    { 64,   0,   0},    /* 11:  dark red */
+    {255, 127,   0},    /* 12:  orange */
+    {192,  96,   0},    /* 13:  darker orange */
+    { 24,  60,   0},    /* 14:  dark green-yellow */
+    { 85, 125, 200},    /* 15:  ice blue */
+    {192, 192, 192}     /* 16:  Netscape/Mosaic gray */
+};
+/* not used for now, but should be for error-checking:
+static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
+ */
+
+/*
+    This whole struct is a fairly cheesy way to keep the number of
+    command-line options to a minimum.  The radial-waves background
+    type is a particularly poor fit to the integer elements of the
+    struct...but a few macros and a little fixed-point math will do
+    wonders for ya.
+
+    type bits:
+       F E D C B A 9 8 7 6 5 4 3 2 1 0
+                             | | | | |
+                             | | +-+-+-- 0 = sharp-edged checkerboard
+                             | |         1 = soft diamonds
+                             | |         2 = radial waves
+                             | |       3-7 = undefined
+                             | +-- gradient #2 inverted?
+                             +-- alternating columns inverted?
+ */
+static struct background_pattern {
+    ush type;
+    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
+    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
+} bg[] = {
+    {0,     1,1, 16,16},        /* checkered:  white vs. light gray (basic) */
+    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
+    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
+    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
+    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
+    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
+    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
+    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
+    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
+    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
+    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
+    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
+    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
+    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
+    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
+    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
+    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
+};
+static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
+
+
+/* X-specific variables */
+static char *displayname;
+static XImage *ximage;
+static Display *display;
+static int depth;
+static Visual *visual;
+static XVisualInfo *visual_list;
+static int RShift, GShift, BShift;
+static ulg RMask, GMask, BMask;
+static Window window;
+static GC gc;
+static Colormap colormap;
+
+static int have_nondefault_visual = FALSE;
+static int have_colormap = FALSE;
+static int have_window = FALSE;
+static int have_gc = FALSE;
+
+
+
+
+int main(int argc, char **argv)
+{
+#ifdef sgi
+    char tmpline[80];
+#endif
+    char *p, *bgstr = NULL;
+    int rc, alen, flen;
+    int error = 0;
+    int timing = FALSE;
+    int have_bg = FALSE;
+#ifdef FEATURE_LOOP
+    int loop = FALSE;
+    long loop_interval = -1;            /* seconds (100,000 max) */
+#endif
+    double LUT_exponent;                /* just the lookup table */
+    double CRT_exponent = 2.2;          /* just the monitor */
+    double default_display_exponent;    /* whole display system */
+    XEvent e;
+    KeySym k;
+
+
+    /* First initialize a few things, just to be sure--memset takes care of
+     * default background color (black), booleans (FALSE), pointers (NULL),
+     * etc. */
+
+    displayname = (char *)NULL;
+    filename = (char *)NULL;
+    memset(&rpng2_info, 0, sizeof(mainprog_info));
+
+
+    /* Set the default value for our display-system exponent, i.e., the
+     * product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities. */
+
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        rpng2_info.display_exponent = atof(p);
+    else
+        rpng2_info.display_exponent = default_display_exponent;
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-display", 2)) {
+            if (!*++argv)
+                ++error;
+            else
+                displayname = *argv;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                rpng2_info.display_exponent = atof(*argv);
+                if (rpng2_info.display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    have_bg = TRUE;
+                    bg_image = FALSE;
+                }
+            }
+        } else if (!strncmp(*argv, "-bgpat", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                pat = atoi(*argv);
+                if (pat >= 0 && pat < num_bgpat) {
+                    bg_image = TRUE;
+                    have_bg = FALSE;
+                } else
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-usleep", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                usleep_duration = (ulg)atol(*argv);
+                demo_timing = TRUE;
+            }
+        } else if (!strncmp(*argv, "-pause", 2)) {
+            pause_after_pass = TRUE;
+        } else if (!strncmp(*argv, "-timing", 2)) {
+            timing = TRUE;
+#ifdef FEATURE_LOOP
+        } else if (!strncmp(*argv, "-loop", 2)) {
+            loop = TRUE;
+            if (!argv[1] || !is_number(argv[1]))
+                loop_interval = 2;
+            else {
+                ++argv;
+                loop_interval = atol(*argv);
+                if (loop_interval < 0)
+                    loop_interval = 2;
+                else if (loop_interval > 100000)   /* bit more than one day */
+                    loop_interval = 100000;
+            }
+#endif
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename)
+        ++error;
+
+
+    /* print usage screen if any errors up to this point */
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
+        readpng2_version_info();
+        fprintf(stderr, "\n"
+          "Usage:   ");
+        fprintf(stderr,
+          "%s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+          "        %*s [-usleep dur | -timing] [-pause]\n",
+          PROGNAME, (int)strlen(PROGNAME), " ");
+        fprintf(stderr,
+#ifdef FEATURE_LOOP
+          "        [-loop [sec]]"
+#endif
+          " file.png\n\n");
+        fprintf(stderr,
+          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n",
+          default_display_exponent);
+        fprintf(stderr,
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images; overrides -bgpat\n"
+          "    pat \tdesired background pattern number (0-%d); used with\n"
+          "\t\t  transparent images; overrides -bgcolor\n",
+          num_bgpat-1);
+#ifdef FEATURE_LOOP
+        fprintf(stderr,
+          "    -loop\tloops through background images after initial display\n"
+          "\t\t  is complete (depends on -bgpat)\n"
+          "    sec \tseconds to display each background image (default = 2)\n");
+#endif
+        fprintf(stderr,
+          "    dur \tduration in microseconds to wait after displaying each\n"
+          "\t\t  row (for demo purposes)\n"
+          "    -timing\tenables delay for every block read, to simulate modem\n"
+          "\t\t  download of image (~36 Kbps)\n"
+          "    -pause\tpauses after displaying each pass until mouse clicked\n"
+          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
+          "is displayed) to quit.\n");
+        exit(1);
+    }
+
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
+            fprintf(stderr, PROGNAME
+              ":  [%s] is not a PNG file: incorrect signature\n",
+              filename);
+            ++error;
+        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
+            switch (rc) {
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng2_init() error\n");
+                    break;
+            }
+            ++error;
+        } else {
+            Trace((stderr, "about to call XOpenDisplay()\n"))
+            display = XOpenDisplay(displayname);
+            if (!display) {
+                readpng2_cleanup(&rpng2_info);
+                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
+                  displayname? displayname : "default");
+                ++error;
+            }
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    if (error) {
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+        exit(2);
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* set some final rpng2_info variables before entering main data loop */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        rpng2_info.bg_red   = (uch)r;
+        rpng2_info.bg_green = (uch)g;
+        rpng2_info.bg_blue  = (uch)b;
+    } else
+        rpng2_info.need_bgcolor = TRUE;
+
+    rpng2_info.state = kPreInit;
+    rpng2_info.mainprog_init = rpng2_x_init;
+    rpng2_info.mainprog_display_row = rpng2_x_display_row;
+    rpng2_info.mainprog_finish_display = rpng2_x_finish_display;
+
+
+    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
+     * the loop to deal with our first buffer of data (read in above to verify
+     * that the file is a PNG image), then loop through the file and continue
+     * calling the same routine to handle each chunk of data.  It in turn
+     * passes the data to libpng, which will invoke one or more of our call-
+     * backs as decoded data become available.  We optionally call sleep() for
+     * one second per iteration to simulate downloading the image via an analog
+     * modem. */
+
+    for (;;) {
+        Trace((stderr, "about to call readpng2_decode_data()\n"))
+        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
+            ++error;
+        Trace((stderr, "done with readpng2_decode_data()\n"))
+
+        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
+            if (rpng2_info.state == kDone) {
+                Trace((stderr, "done decoding PNG image\n"))
+            } else if (ferror(infile)) {
+                fprintf(stderr, PROGNAME
+                  ":  error while reading PNG image file\n");
+                exit(3);
+            } else if (feof(infile)) {
+                fprintf(stderr, PROGNAME ":  end of file reached "
+                  "(unexpectedly) while reading PNG image file\n");
+                exit(3);
+            } else /* if (error) */ {
+                /* will print error message below */
+            }
+            break;
+        }
+
+        if (timing)
+            sleep(1);
+
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+    }
+
+
+    /* clean up PNG stuff and report any decoding errors */
+
+    fclose(infile);
+    Trace((stderr, "about to call readpng2_cleanup()\n"))
+    readpng2_cleanup(&rpng2_info);
+
+    if (error) {
+        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
+        exit(3);
+    }
+
+
+#ifdef FEATURE_LOOP
+
+    if (loop && bg_image) {
+        Trace((stderr, "entering -loop loop (FEATURE_LOOP)\n"))
+        for (;;) {
+            int i, use_sleep;
+            struct timeval now, then;
+
+            /* get current time and add loop_interval to get target time */
+            if (gettimeofday(&then, NULL) == 0) {
+                then.tv_sec += loop_interval;
+                use_sleep = FALSE;
+            } else
+                use_sleep = TRUE;
+
+            /* do quick check for a quit event but don't wait for it */
+            /* GRR BUG:  should also check for Expose events and redraw... */
+            if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask, &e))
+                if (QUIT(e,k))
+                    break;
+
+            /* generate next background image */
+            if (++pat >= num_bgpat)
+                pat = 0;
+            rpng2_x_reload_bg_image();
+
+            /* wait for timeout, using whatever means are available */
+            if (use_sleep || gettimeofday(&now, NULL) != 0) {
+                for (i = loop_interval;  i > 0;  --i) {
+                    sleep(1);
+                    /* GRR BUG:  also need to check for Expose (and redraw!) */
+                    if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask,
+                        &e) && QUIT(e,k))
+                        break;
+                }
+            } else {
+                /* Y2038 BUG! */
+                if (now.tv_sec < then.tv_sec ||
+                    (now.tv_sec == then.tv_sec && now.tv_usec < then.tv_usec))
+                {
+                    int quit = FALSE;
+                    long seconds_to_go = then.tv_sec - now.tv_sec;
+                    long usleep_usec;
+
+                    /* basically chew up most of remaining loop-interval with
+                     *  calls to sleep(1) interleaved with checks for quit
+                     *  events, but also recalc time-to-go periodically; when
+                     *  done, clean up any remaining time with usleep() call
+                     *  (could also use SIGALRM, but signals are a pain...) */
+                    while (seconds_to_go-- > 1) {
+                        int seconds_done = 0;
+
+                        for (i = seconds_to_go;  i > 0 && !quit;  --i) {
+                            sleep(1);
+                            /* GRR BUG:  need to check for Expose and redraw */
+                            if (XCheckMaskEvent(display, KeyPressMask |
+                                ButtonPressMask, &e) && QUIT(e,k))
+                                quit = TRUE;
+                            if (++seconds_done > 1000)
+                                break;   /* time to redo seconds_to_go meas. */
+                        }
+                        if (quit)
+                            break;
+
+                        /* OK, more than 1000 seconds since last check:
+                         *  correct the time-to-go measurement for drift */
+                        if (gettimeofday(&now, NULL) == 0) {
+                            if (now.tv_sec >= then.tv_sec)
+                                break;
+                            seconds_to_go = then.tv_sec - now.tv_sec;
+                        } else
+                            ++seconds_to_go;  /* restore what we subtracted */
+                    }
+                    if (quit)
+                        break;   /* breaks outer do-loop, skips redisplay */
+
+                    /* since difference between "now" and "then" is already
+                     *  eaten up to within a couple of seconds, don't need to
+                     *  worry about overflow--but might have overshot (neg.) */
+                    if (gettimeofday(&now, NULL) == 0) {
+                        usleep_usec = 1000000L*(then.tv_sec - now.tv_sec) +
+                          then.tv_usec - now.tv_usec;
+                        if (usleep_usec > 0)
+                            usleep((ulg)usleep_usec);
+                    }
+                }
+            }
+
+            /* composite image against new background and display (note that
+             *  we do not take into account the time spent doing this...) */
+            rpng2_x_redisplay_image (0, 0, rpng2_info.width, rpng2_info.height);
+        }
+
+    } else /* FALL THROUGH and do the normal thing */
+
+#endif /* FEATURE_LOOP */
+
+    /* wait for the user to tell us when to quit */
+
+    if (rpng2_info.state >= kWindowInit) {
+        Trace((stderr, "entering final wait-for-quit-event loop\n"))
+        do {
+            XNextEvent(display, &e);
+            if (e.type == Expose) {
+                XExposeEvent *ex = (XExposeEvent *)&e;
+                rpng2_x_redisplay_image (ex->x, ex->y, ex->width, ex->height);
+            }
+        } while (!QUIT(e,k));
+    } else {
+        fprintf(stderr, PROGNAME ":  init callback never called:  probable "
+          "libpng error while decoding PNG metadata\n");
+        exit(4);
+    }
+
+
+    /* we're done:  clean up all image and X resources and go away */
+
+    Trace((stderr, "about to call rpng2_x_cleanup()\n"))
+    rpng2_x_cleanup();
+
+    (void)argc; /* Unused */
+
+    return 0;
+}
+
+
+
+
+
+/* this function is called by readpng2_info_callback() in readpng2.c, which
+ * in turn is called by libpng after all of the pre-IDAT chunks have been
+ * read and processed--i.e., we now have enough info to finish initializing */
+
+static void rpng2_x_init(void)
+{
+    ulg i;
+    ulg rowbytes = rpng2_info.rowbytes;
+
+    Trace((stderr, "beginning rpng2_x_init()\n"))
+    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
+    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
+    Trace((stderr, "  height = %ld\n", rpng2_info.height))
+
+    /* Guard against integer overflow */
+    if (rpng2_info.height > ((size_t)(-1))/rpng2_info.rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n");
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
+    if (!rpng2_info.image_data) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
+    if (!rpng2_info.row_pointers) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    for (i = 0;  i < rpng2_info.height;  ++i)
+        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
+
+
+    /* do the basic X initialization stuff, make the window, and fill it with
+     * the user-specified, file-specified or default background color or
+     * pattern */
+
+    if (rpng2_x_create_window()) {
+
+        /* GRR TEMPORARY HACK:  this is fundamentally no different from cases
+         * above; libpng should call our error handler to longjmp() back to us
+         * when png_ptr goes away.  If we/it segfault instead, seems like a
+         * libpng bug... */
+
+        /* we're here via libpng callback, so if window fails, clean and bail */
+        readpng2_cleanup(&rpng2_info);
+        rpng2_x_cleanup();
+        exit(2);
+    }
+
+    rpng2_info.state = kWindowInit;
+}
+
+
+
+
+
+static int rpng2_x_create_window(void)
+{
+    ulg bg_red   = rpng2_info.bg_red;
+    ulg bg_green = rpng2_info.bg_green;
+    ulg bg_blue  = rpng2_info.bg_blue;
+    ulg bg_pixel = 0L;
+    ulg attrmask;
+    int need_colormap = FALSE;
+    int screen, pad;
+    uch *xdata;
+    Window root;
+    XEvent e;
+    XGCValues gcvalues;
+    XSetWindowAttributes attr;
+    XTextProperty windowName, *pWindowName = &windowName;
+    XTextProperty iconName, *pIconName = &iconName;
+    XVisualInfo visual_info;
+    XSizeHints *size_hints;
+    XWMHints *wm_hints;
+    XClassHint *class_hints;
+
+
+    Trace((stderr, "beginning rpng2_x_create_window()\n"))
+
+    screen = DefaultScreen(display);
+    depth = DisplayPlanes(display, screen);
+    root = RootWindow(display, screen);
+
+#ifdef DEBUG
+    XSynchronize(display, True);
+#endif
+
+    if (depth != 16 && depth != 24 && depth != 32) {
+        int visuals_matched = 0;
+
+        Trace((stderr, "default depth is %d:  checking other visuals\n",
+          depth))
+
+        /* 24-bit first */
+        visual_info.screen = screen;
+        visual_info.depth = 24;
+        visual_list = XGetVisualInfo(display,
+          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
+        if (visuals_matched == 0) {
+/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
+            fprintf(stderr, "default screen depth %d not supported, and no"
+              " 24-bit visuals found\n", depth);
+            return 2;
+        }
+        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
+          visuals_matched))
+        visual = visual_list[0].visual;
+        depth = visual_list[0].depth;
+/*
+        colormap_size = visual_list[0].colormap_size;
+        visual_class = visual->class;
+        visualID = XVisualIDFromVisual(visual);
+ */
+        have_nondefault_visual = TRUE;
+        need_colormap = TRUE;
+    } else {
+        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
+        visual = visual_info.visual;
+    }
+
+    RMask = visual->red_mask;
+    GMask = visual->green_mask;
+    BMask = visual->blue_mask;
+
+/* GRR:  add/check 8-bit support */
+    if (depth == 8 || need_colormap) {
+        colormap = XCreateColormap(display, root, visual, AllocNone);
+        if (!colormap) {
+            fprintf(stderr, "XCreateColormap() failed\n");
+            return 2;
+        }
+        have_colormap = TRUE;
+        if (depth == 8)
+            bg_image = FALSE;   /* gradient just wastes palette entries */
+    }
+    if (depth == 15 || depth == 16) {
+        RShift = 15 - rpng2_x_msb(RMask);    /* these are right-shifts */
+        GShift = 15 - rpng2_x_msb(GMask);
+        BShift = 15 - rpng2_x_msb(BMask);
+    } else if (depth > 16) {
+        RShift = rpng2_x_msb(RMask) - 7;     /* these are left-shifts */
+        GShift = rpng2_x_msb(GMask) - 7;
+        BShift = rpng2_x_msb(BMask) - 7;
+    }
+    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
+        fprintf(stderr, "rpng2 internal logic error:  negative X shift(s)!\n");
+        return 2;
+    }
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    attr.backing_store = Always;
+    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
+    attrmask = CWBackingStore | CWEventMask;
+    if (have_nondefault_visual) {
+        attr.colormap = colormap;
+        attr.background_pixel = 0;
+        attr.border_pixel = 1;
+        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
+    }
+
+    window = XCreateWindow(display, root, 0, 0, rpng2_info.width,
+      rpng2_info.height, 0, depth, InputOutput, visual, attrmask, &attr);
+
+    if (window == None) {
+        fprintf(stderr, "XCreateWindow() failed\n");
+        return 2;
+    } else
+        have_window = TRUE;
+
+    if (depth == 8)
+        XSetWindowColormap(display, window, colormap);
+
+    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
+        pWindowName = NULL;
+    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
+        pIconName = NULL;
+
+    /* OK if either hints allocation fails; XSetWMProperties() allows NULLs */
+
+    if ((size_hints = XAllocSizeHints()) != NULL) {
+        /* window will not be resizable */
+        size_hints->flags = PMinSize | PMaxSize;
+        size_hints->min_width = size_hints->max_width = (int)rpng2_info.width;
+        size_hints->min_height = size_hints->max_height =
+          (int)rpng2_info.height;
+    }
+
+    if ((wm_hints = XAllocWMHints()) != NULL) {
+        wm_hints->initial_state = NormalState;
+        wm_hints->input = True;
+     /* wm_hints->icon_pixmap = icon_pixmap; */
+        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
+    }
+
+    if ((class_hints = XAllocClassHint()) != NULL) {
+        class_hints->res_name = res_name;
+        class_hints->res_class = res_class;
+    }
+
+    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
+      size_hints, wm_hints, class_hints);
+
+    /* various properties and hints no longer needed; free memory */
+    if (pWindowName)
+       XFree(pWindowName->value);
+    if (pIconName)
+       XFree(pIconName->value);
+    if (size_hints)
+        XFree(size_hints);
+    if (wm_hints)
+       XFree(wm_hints);
+    if (class_hints)
+       XFree(class_hints);
+
+    XMapWindow(display, window);
+
+    gc = XCreateGC(display, window, 0, &gcvalues);
+    have_gc = TRUE;
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the X- and display-specific version of the image.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        xdata = (uch *)malloc(4*rpng2_info.width*rpng2_info.height);
+        pad = 32;
+    } else if (depth == 16) {
+        xdata = (uch *)malloc(2*rpng2_info.width*rpng2_info.height);
+        pad = 16;
+    } else /* depth == 8 */ {
+        xdata = (uch *)malloc(rpng2_info.width*rpng2_info.height);
+        pad = 8;
+    }
+
+    if (!xdata) {
+        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
+        return 4;
+    }
+
+    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
+      (char *)xdata, rpng2_info.width, rpng2_info.height, pad, 0);
+
+    if (!ximage) {
+        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
+        free(xdata);
+        return 3;
+    }
+
+    /* to avoid testing the byte order every pixel (or doubling the size of
+     * the drawing routine with a giant if-test), we arbitrarily set the byte
+     * order to MSBFirst and let Xlib worry about inverting things on little-
+     * endian machines (e.g., Linux/x86, old VAXen, etc.)--this is not the
+     * most efficient approach (the giant if-test would be better), but in
+     * the interest of clarity, we'll take the easy way out... */
+
+    ximage->byte_order = MSBFirst;
+
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color (default is black) or
+    faked "background image" (but latter is disabled if 8-bit; gradients
+    just waste palette entries).
+  ---------------------------------------------------------------------------*/
+
+    if (bg_image)
+        rpng2_x_load_bg_image();    /* resets bg_image if fails */
+
+    if (!bg_image) {
+        if (depth == 24 || depth == 32) {
+            bg_pixel = (bg_red   << RShift) |
+                       (bg_green << GShift) |
+                       (bg_blue  << BShift);
+        } else if (depth == 16) {
+            bg_pixel = (((bg_red   << 8) >> RShift) & RMask) |
+                       (((bg_green << 8) >> GShift) & GMask) |
+                       (((bg_blue  << 8) >> BShift) & BMask);
+        } else /* depth == 8 */ {
+
+            /* GRR:  add 8-bit support */
+
+        }
+        XSetForeground(display, gc, bg_pixel);
+        XFillRectangle(display, window, gc, 0, 0, rpng2_info.width,
+          rpng2_info.height);
+    }
+
+/*---------------------------------------------------------------------------
+    Wait for first Expose event to do any drawing, then flush and return.
+  ---------------------------------------------------------------------------*/
+
+    do
+        XNextEvent(display, &e);
+    while (e.type != Expose || e.xexpose.count);
+
+    XFlush(display);
+
+    return 0;
+
+} /* end function rpng2_x_create_window() */
+
+
+
+
+
+static int rpng2_x_load_bg_image(void)
+{
+    uch *src;
+    char *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max;
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    int ximage_rowbytes = ximage->bytes_per_line;
+    ulg i, row;
+    ulg pixel;
+
+/*---------------------------------------------------------------------------
+    Allocate buffer for fake background image to be used with transparent
+    images; if this fails, revert to plain background color.
+  ---------------------------------------------------------------------------*/
+
+    bg_rowbytes = 3 * rpng2_info.width;
+    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
+    if (!bg_data) {
+        fprintf(stderr, PROGNAME
+          ":  unable to allocate memory for background image\n");
+        bg_image = 0;
+        return 1;
+    }
+
+    bgscale = (pat == 0)? 8 : bgscale_default;
+    yidx_max = bgscale - 1;
+
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            even_odd_vert = (int)((row / bgscale) & 1);
+
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (int)((i / bgscale) & 1);
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {        /* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {                    /* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;       /* not inverted or */
+                        *dest++ = g2;       /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;   /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 1) {
+
+        hmax = (bgscale-1)/2;   /* half the max weight of a color */
+        max = 2*hmax;           /* the max weight of a color */
+
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = (int)(i % bgscale);
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+
+        fprintf(stderr, "%s:  computing radial background...",
+          PROGNAME);
+        fflush(stderr);
+
+        hh = (int)(rpng2_info.height / 2);
+        hw = (int)(rpng2_info.width / 2);
+
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = (int)(row - hh);
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = (int)(i - hw);
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+        fprintf(stderr, "done.\n");
+        fflush(stderr);
+    }
+
+/*---------------------------------------------------------------------------
+    Blast background image to display buffer before beginning PNG decode.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        int bpp = ximage->bits_per_pixel;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            src = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (bpp == 32) {    /* slightly optimized version */
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
+                    /*           (probably need to use RShift, RMask, etc.) */
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            src = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = ((ush)(*src) << 8);  ++src;
+                green = ((ush)(*src) << 8);  ++src;
+                blue  = ((ush)(*src) << 8);  ++src;
+                pixel = ((red   >> RShift) & RMask) |
+                        ((green >> GShift) & GMask) |
+                        ((blue  >> BShift) & BMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = (char)((pixel >>  8) & 0xff);
+                *dest++ = (char)( pixel        & 0xff);
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    XPutImage(display, window, gc, ximage, 0, 0, 0, 0, rpng2_info.width,
+      rpng2_info.height);
+
+    return 0;
+
+} /* end function rpng2_x_load_bg_image() */
+
+
+
+
+
+static void rpng2_x_display_row(ulg row)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL;
+    char *dest;
+    uch r, g, b, a;
+    int ximage_rowbytes = ximage->bytes_per_line;
+    ulg i, pixel;
+    static int rows=0, prevpass=(-1);
+    static ulg firstrow;
+
+/*---------------------------------------------------------------------------
+    rows and firstrow simply track how many rows (and which ones) have not
+    yet been displayed; alternatively, we could call XPutImage() for every
+    row and not bother with the records-keeping.
+  ---------------------------------------------------------------------------*/
+
+    Trace((stderr, "beginning rpng2_x_display_row()\n"))
+
+    if (rpng2_info.pass != prevpass) {
+        if (pause_after_pass && rpng2_info.pass > 0) {
+            XEvent e;
+            KeySym k;
+
+            fprintf(stderr,
+              "%s:  end of pass %d of 7; click in image window to continue\n",
+              PROGNAME, prevpass + 1);
+            do
+                XNextEvent(display, &e);
+            while (!QUIT(e,k));
+        }
+        fprintf(stderr, "%s:  pass %d of 7\r", PROGNAME, rpng2_info.pass + 1);
+        fflush(stderr);
+        prevpass = rpng2_info.pass;
+    }
+
+    if (rows == 0)
+        firstrow = row;   /* first row that is not yet displayed */
+
+    ++rows;   /* count of rows received but not yet displayed */
+
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct, the lack of an outer loop
+    (over rows) and moving the XPutImage() call outside the "if (depth)"
+    tests, this routine is identical to rpng_x_display_image() in the non-
+    progressive version of the program.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        int bpp = ximage->bits_per_pixel;
+
+        src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+        if (bg_image)
+            src2 = bg_data + row*bg_rowbytes;
+        dest = ximage->data + row*ximage_rowbytes;
+        if (rpng2_info.channels == 3) {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = *src++;
+                green = *src++;
+                blue  = *src++;
+                pixel = (red   << RShift) |
+                        (green << GShift) |
+                        (blue  << BShift);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                if (bpp == 32) {
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                } else {
+                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
+                    /*           (probably need to use RShift, RMask, etc.) */
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+        } else /* if (rpng2_info.channels == 4) */ {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (bg_image) {
+                    bg_red   = *src2++;
+                    bg_green = *src2++;
+                    bg_blue  = *src2++;
+                }
+                if (a == 255) {
+                    red   = r;
+                    green = g;
+                    blue  = b;
+                } else if (a == 0) {
+                    red   = bg_red;
+                    green = bg_green;
+                    blue  = bg_blue;
+                } else {
+                    /* this macro (from png.h) composites the foreground
+                     * and background values and puts the result into the
+                     * first argument */
+                    alpha_composite(red,   r, a, bg_red);
+                    alpha_composite(green, g, a, bg_green);
+                    alpha_composite(blue,  b, a, bg_blue);
+                }
+                pixel = (red   << RShift) |
+                        (green << GShift) |
+                        (blue  << BShift);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                if (bpp == 32) {
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                } else {
+                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
+                    /*           (probably need to use RShift, RMask, etc.) */
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        src = rpng2_info.row_pointers[row];
+        if (bg_image)
+            src2 = bg_data + row*bg_rowbytes;
+        dest = ximage->data + row*ximage_rowbytes;
+        if (rpng2_info.channels == 3) {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = ((ush)(*src) << 8);
+                ++src;
+                green = ((ush)(*src) << 8);
+                ++src;
+                blue  = ((ush)(*src) << 8);
+                ++src;
+                pixel = ((red   >> RShift) & RMask) |
+                        ((green >> GShift) & GMask) |
+                        ((blue  >> BShift) & BMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = (char)((pixel >>  8) & 0xff);
+                *dest++ = (char)( pixel        & 0xff);
+            }
+        } else /* if (rpng2_info.channels == 4) */ {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (bg_image) {
+                    bg_red   = *src2++;
+                    bg_green = *src2++;
+                    bg_blue  = *src2++;
+                }
+                if (a == 255) {
+                    red   = ((ush)r << 8);
+                    green = ((ush)g << 8);
+                    blue  = ((ush)b << 8);
+                } else if (a == 0) {
+                    red   = ((ush)bg_red   << 8);
+                    green = ((ush)bg_green << 8);
+                    blue  = ((ush)bg_blue  << 8);
+                } else {
+                    /* this macro (from png.h) composites the foreground
+                     * and background values and puts the result back into
+                     * the first argument (== fg byte here:  safe) */
+                    alpha_composite(r, r, a, bg_red);
+                    alpha_composite(g, g, a, bg_green);
+                    alpha_composite(b, b, a, bg_blue);
+                    red   = ((ush)r << 8);
+                    green = ((ush)g << 8);
+                    blue  = ((ush)b << 8);
+                }
+                pixel = ((red   >> RShift) & RMask) |
+                        ((green >> GShift) & GMask) |
+                        ((blue  >> BShift) & BMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = (char)((pixel >>  8) & 0xff);
+                *dest++ = (char)( pixel        & 0xff);
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+
+/*---------------------------------------------------------------------------
+    Display after every 16 rows or when on one of last two rows.  (Region
+    may include previously displayed lines due to interlacing--i.e., not
+    contiguous.  Also, second-to-last row is final one in interlaced images
+    with odd number of rows.)  For demos, flush (and delay) after every 16th
+    row so "sparse" passes don't go twice as fast.
+  ---------------------------------------------------------------------------*/
+
+    if (demo_timing && (row - firstrow >= 16 || row >= rpng2_info.height-2)) {
+        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
+          (int)firstrow, rpng2_info.width, row - firstrow + 1);
+        XFlush(display);
+        rows = 0;
+        usleep(usleep_duration);
+    } else
+    if (!demo_timing && ((rows & 0xf) == 0 || row >= rpng2_info.height-2)) {
+        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
+          (int)firstrow, rpng2_info.width, row - firstrow + 1);
+        XFlush(display);
+        rows = 0;
+    }
+
+}
+
+
+
+
+
+static void rpng2_x_finish_display(void)
+{
+    Trace((stderr, "beginning rpng2_x_finish_display()\n"))
+
+    /* last row has already been displayed by rpng2_x_display_row(), so we
+     * have nothing to do here except set a flag and let the user know that
+     * the image is done */
+
+    rpng2_info.state = kDone;
+    printf(
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
+    fflush(stdout);
+}
+
+
+
+
+
+static void rpng2_x_redisplay_image(ulg startcol, ulg startrow,
+                                    ulg width, ulg height)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL;
+    char *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow = 0;
+    ulg pixel;
+    int ximage_rowbytes = ximage->bytes_per_line;
+
+
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      rpng2_info.channels))
+    Trace((stderr, "   (width = %ld, rowbytes = %d, ximage_rowbytes = %d)\n",
+      rpng2_info.width, rpng2_info.rowbytes, ximage_rowbytes))
+    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
+    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
+      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
+
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct and of src2 (for background
+    image), this routine is identical to rpng_x_display_image() in the non-
+    progressive version of the program--for the simple reason that redisplay
+    of the image against a new background happens after the image is fully
+    decoded and therefore is, by definition, non-progressive.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        int bpp = ximage->bits_per_pixel;
+
+        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
+            src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+            if (bg_image)
+                src2 = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (rpng2_info.channels == 3) {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift, RMask, etc.) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* GRR BUG */
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift/RMask/etc. here, too) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#endif
+                }
+
+            } else /* if (rpng2_info.channels == 4) */ {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (bg_image) {
+                        bg_red   = *src2++;
+                        bg_green = *src2++;
+                        bg_blue  = *src2++;
+                    }
+                    if (a == 255) {
+                        red   = r;
+                        green = g;
+                        blue  = b;
+                    } else if (a == 0) {
+                        red   = bg_red;
+                        green = bg_green;
+                        blue  = bg_blue;
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result into the
+                         * first argument */
+                        alpha_composite(red,   r, a, bg_red);
+                        alpha_composite(green, g, a, bg_green);
+                        alpha_composite(blue,  b, a, bg_blue);
+                    }
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift, RMask, etc.) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* GRR BUG */
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift/RMask/etc. here, too) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#endif
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, rpng2_info.width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
+            src = rpng2_info.row_pointers[row];
+            if (bg_image)
+                src2 = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (rpng2_info.channels == 3) {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = ((ush)(*src) << 8);
+                    ++src;
+                    green = ((ush)(*src) << 8);
+                    ++src;
+                    blue  = ((ush)(*src) << 8);
+                    ++src;
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else /* if (rpng2_info.channels == 4) */ {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (bg_image) {
+                        bg_red   = *src2++;
+                        bg_green = *src2++;
+                        bg_blue  = *src2++;
+                    }
+                    if (a == 255) {
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    } else if (a == 0) {
+                        red   = ((ush)bg_red   << 8);
+                        green = ((ush)bg_green << 8);
+                        blue  = ((ush)bg_blue  << 8);
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result back into
+                         * the first argument (== fg byte here:  safe) */
+                        alpha_composite(r, r, a, bg_red);
+                        alpha_composite(g, g, a, bg_green);
+                        alpha_composite(b, b, a, bg_blue);
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    }
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, rpng2_info.width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    Trace((stderr, "calling final XPutImage()\n"))
+    if (lastrow < startrow+height) {
+        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+          (int)lastrow, rpng2_info.width, rpng2_info.height-lastrow);
+        XFlush(display);
+    }
+
+    (void)startcol;
+    (void)width;
+
+} /* end function rpng2_x_redisplay_image() */
+
+
+
+
+
+#ifdef FEATURE_LOOP
+
+static void rpng2_x_reload_bg_image(void)
+{
+    char *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max;
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    ulg i, row;
+
+
+    bgscale = (pat == 0)? 8 : bgscale_default;
+    yidx_max = bgscale - 1;
+
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            even_odd_vert = (int)((row / bgscale) & 1);
+
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (int)((i / bgscale) & 1);
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {        /* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {                    /* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;       /* not inverted or */
+                        *dest++ = g2;       /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;   /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 1) {
+
+        hmax = (bgscale-1)/2;   /* half the max weight of a color */
+        max = 2*hmax;           /* the max weight of a color */
+
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = (int)(i % bgscale);
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+
+        hh = (int)(rpng2_info.height / 2);
+        hw = (int)(rpng2_info.width / 2);
+
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = (int)(row - hh);
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = (int)(i - hw);
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+    }
+
+} /* end function rpng2_x_reload_bg_image() */
+
+
+
+
+
+static int is_number(char *p)
+{
+    while (*p) {
+        if (!isdigit(*p))
+            return FALSE;
+        ++p;
+    }
+    return TRUE;
+}
+
+#endif /* FEATURE_LOOP */
+
+
+
+
+
+static void rpng2_x_cleanup(void)
+{
+    if (bg_image && bg_data) {
+        free(bg_data);
+        bg_data = NULL;
+    }
+
+    if (rpng2_info.image_data) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+    }
+
+    if (rpng2_info.row_pointers) {
+        free(rpng2_info.row_pointers);
+        rpng2_info.row_pointers = NULL;
+    }
+
+    if (ximage) {
+        if (ximage->data) {
+            free(ximage->data);           /* we allocated it, so we free it */
+            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
+        }
+        XDestroyImage(ximage);
+        ximage = NULL;
+    }
+
+    if (have_gc)
+        XFreeGC(display, gc);
+
+    if (have_window)
+        XDestroyWindow(display, window);
+
+    if (have_colormap)
+        XFreeColormap(display, colormap);
+
+    if (have_nondefault_visual)
+        XFree(visual_list);
+}
+
+
+
+
+
+static int rpng2_x_msb(ulg u32val)
+{
+    int i;
+
+    for (i = 31;  i >= 0;  --i) {
+        if (u32val & 0x80000000L)
+            break;
+        u32val <<= 1;
+    }
+    return i;
+}
diff --git a/extern/libpng/contrib/gregbook/toucan.png b/extern/libpng/contrib/gregbook/toucan.png
new file mode 100644
index 0000000000000000000000000000000000000000..03960d4939938541ca3f8efee4bf13ffdecbb2f5
GIT binary patch
literal 12901
zcma*NWpo@(vMt(@TFlH07Be$5GlRv<%*<@D#mr!V#mp>=(Xz$NEcMklbI#m(>%AXu
zud1#cJ2EmWGkdMBijHVyMJYr$JU9RVfG8s^uKIZ``aIKNAOHX`!oF1CrvbDSQ4j%u
zMHH|cr5gbN5CCO)b%{^?{|#6GI1B*%zje6(GU5NlRXmX=`N0_(A%xV>KIS3t$)QLv
zQPAKaY!jf6!6DFKA+BP;aS(tXOVE|;Uwp<0CBPx<gdhY=ASnbPaj_s&5?~~tAV{$x
z?!SYd{AT5&W8qaq0s{bkCqss(un;4lvcf_(Mj(IQ10fvj(>ek%2QX+9N}6AR78ggv
z7y<(tDDvfVZh(LUC<bE)7P^08xm_SQ82=GfJ%LDw{}4J(IQKEc^f9RWNoW`_fRPIn
z5jg}J7!Vs8ic=lJegKLF4<d~doQ4I$A_3Wm34#C%^4K1nUkmNCH!v^&9z4WDA2<pG
z1OfsCHu67f_=!)~f8*aRKNaMEEeq6t`N{sJ-~qr<0FeLo{&(PiIO6A4{0s2^75gb5
z{Y(Gci~qFz4?zHcA^dODf5cA$|NkZarvc3Wvwsvw@XtAZ9-sL4q@<yMpX9k0{NLuk
z_5bislb8x<Ywpd(hR7EJ0R|4>aDtRFhN+r_B0_*rDFZ%cgL7s9GZxYKaNytiAy8o<
zK4ankJ;1+)_%uHc3<!wNDPhAwzD+@J5PxY|MikG0d@ci5uR|t-hxoY&En<qn?|}B%
zzfcgIBo9JdcnUE&3@Y3|>!1etPoK|Y|FdGB%Ksn01O8|4J{$jgBVYkwFaQWRFz_wD
zcdvi$%1u>K4FFaS4p9LFfgquvVL)(YupoHQKUfBRfZqSbKFR+@Ea>gi5dR<H15^qE
zEtr5n{Gc*~f3&gxae)36bgiB7X}i5D7C7>;(-VdVC4xLbxrnJC%1@d03#v_sPy`DI
z#TlfBgvIoM42mg1!!%U~fzbW3@x?JfxW%NBWH@-~(jYE^qPPz?TWuREkU7XeRz^L5
z)zI>vp=|&8_%|jKPuzGs^^^~C_x@J`fdc-aA1WYukOQ_TO;%<;MIbQ=x!`vn5GPw2
zDEZULr+>x^0FVG=#6{G-*3W$5xfh>5grL|M$^WKI4*jfQiPuZU9gHbtfkr=&WwSL%
zv5i1cx)_WYB{v`4mr;p<qg0P+hN4`MfaXxov7_E{`?2(E?H1%G)v|teaCZFt_El)M
z=NFEV(WSTlcH8Xh`$t!=s%l_JNR86QFVjTX+1>~|&T`^d9t;6jdFSmVAcQM70jBuR
z?DCrr)rN21M1F^DwpOHf(0Mmq*4qpki|KZmt3(dweY4NV@07ejk{o^Dj1K4fcG!3)
zmiU_>G75d9f^4;3ONXdK8*Syu3Oq-&Fs{+WHBQPe)5^eBia)QXHevUq^>0j=YYxq1
zB+txJ=r8k!mYI=D>GaJw4tvu-T~01;PbspQHcxpxJu_VUW+NH;R(d179U8i_FNCbA
zwTha**o3-x!OATw-r&eCuV9z{C@*n8#^%rlbXQfCAf#?XG)O8QO22baFPc2fG>~X|
zd~hg+BxsqcH*37}8-u?KBY`s-bLaVS8kzFrX8E&GN<CbDM-Re~ku}U;rP%!D!~aL;
zq7yTUx01}z@mCnh^GffTWbB-+-Bc9%mDsA${h!E7<DB|DW{V$dVCP1t6yP-+?WJ_O
zmyK~7Eg$EJhmRY}0?^oqQVyOtxF*a~m;0@0>^6>mDhQ10CbQ3L<H`F;(NSX04XkZE
z8#d(Q+}^!@w+y0B)LOE#0W(ORg1p*hxbIce-+Ru7BNMeYO<wUl_~kk29M#^TZIcy)
zD`odX_s5kSlha=uQwFb&e+@3jm8||2`UwkbS>xi=&_;aGYt|XqdtN;~3<tl1Q(fr%
zjeDYTzR`j?Wu_BjYKT2zpQ)LIV%Atz{%{vp(NPvpNj+j;U?-;@_&Ti+FgK~g@aLPL
zWmeo&|H4y9^W-C5eb~?QtV91AMH>6;Z*~)4-@L|zt7WFJnPXDgMrr8A21>xD4=rh$
zx`f?YYcTI(hX3>x!gd7Bzll48xv8_uIG!QIPa7CH@SCu)u$W9qWmWB{dV;-)lU;gy
zrZ~1WzKNTO9kl4yIfN7!cOx6JS>3&o@MfSeR}o<2s$6g5b~aL{=3Thj#yPk%H&T%k
zMei>yxv*|<cGJIO1yYj_Rt<BAT3^hdvU&i;1WaSP!zup)!MBFOfG-+Zk(Kpi$XySh
z-Jx{u=f{w*3pTU36XQ!BrtxOq{hU}8_j?O~az&4$!8_w4gg=EG?H4D@Gg(;^kul@!
zqmbQm-{*-jC#4+56w^U&_dKKUMa3sJs?A1bE8R0fC`A221eeXTfv@F0VH({&nybo%
z6s1Z0N#zufLk3>_41?~8XXWyxJEjpdU9Ytvo!J9{E6bqAMJ|57^@09uM(LNqjWbvT
z=vO{Z`o4IWFz~a-5L!6QqXIU&K;9!WpZ#muwl3C|aK~E3-!<A2<&n>kGZ^AhQkMD-
zNVB@qHx)LBh%*!J=)fRmn(Md1ij+BYU#uIq!iaudTOu^1NOBc$-e6LMS-%EXuu?gO
zOO8z476;7!Q)fx5+da3Z(6O%^&*3B|=+Q5DhO92EIW?TE&H6}N&MUQ|`=)W~N5d8q
zeZo`dV`JR*KInu?DgHw(6|6s=R?OM@9kyZPjJBuxf^aGV4I3B)NA54~PWJ?oeO+TU
z0{6K^)5-3oX|(o{5Umk8vaAb^um_P!DySz0jftfY9h<A#no8T+q&NB4*(sNqn94U8
ze`?aGZnSW4b#444*w(q8`<CU57Wg1B0q!DMEWy6XL4btcsYy>|BQH<!t+&fd%|965
z`Xo1m?F0;GYY5g9B|Kr>Z>4u};|3qQZ&8o^Qu2Et)yj?hmk6_-CjWtv)m5?}1ryI;
z&^H#i94EsMvA(`WXZqyIvH9nNpGf%$l`VZgv`n88sQFF55!H0Cc~3rg(wXkcGw_{_
zt;m$MVBwIOexEax%UEk}WVC6%5bw}av9fyUw9l{+f9MLhh%5Jj&KmEsm);H3icisL
z+BH8OoOg#*(ZqFs^_+<Y#8Mh@9h)2<XV;wl@o;YU7z1L!NJAF#U6^+@R^gAu`C-#M
zYgf@E@D6kfDpFP7-Ydhx!Zx~e7K`FlacXgPlwGQ(_<vDzv)79(XTpo*NEu9#+UrZ0
z!X6XoY10wW6{K7{zppQ{JULG0-`mSvab{)R;C)G71pl$`I2M4kOk3M5z<M|sZ+YfZ
zvF^eu_q}0t>l!;V2TmCV!|!p*b~q6ndvDZ!*IIy8@s%}mJCUoS%mJZR9PUZ3C~-fq
zNGyCRYe}(mtu>VkSwi7p?PUWz@tDaz?rliToGWq!+wLxr-p|QvBv5N2^h&_+2R>4|
zSwNGJj3cu3rVx(~Wp#6DW4pX2&+z+)@SO;q-lLMB9wnKp<y!hz>&kC;6Z%QCvUGyd
zE!hf*uX~bfZv;Btn7@zV%#}1K^HDQ&bktgdP6xNgWpzIc&LS#DXeMRfB|v;|trpze
z+7MrXq_F-Vi#&&2W9OHI_p1hh)qt~e1~(j;kQ<w!XQ37)UrN}?Ua}*U8bbQBbESN!
zvxwT%iDW~x6Q(H@jc@N-Pai>lT)9V(bPqf)j<iF~zM1T6dV5yeo_5;_7v9&F$2>$z
zh+EL~V@);)wPv${r7UT@SP;d1+<~o}_4oHzha%+wy6OGz4$ceX(s@_LQ_XE+*{_tj
zzY;3hmCedgXs;rJ5L%^xZy81b(eV;PqG5~A8<n+@v7&ZLg3~%?2Wm(wbC(<>ND9{+
znpdmTKs1^HJ!GU-vo_A1TKW3%II9ZohSLBC=bn?VYBVL1=&QKCq~EIRCxQ^MOA4-4
zeyrWs#@9`2y+J3eb%aat*UPFrBZ%EW)7V5IHb?0ySbF1~QoQwTcNMxB`MKSZR)@qj
zr>9I7O6k9U`NfuRLGux8qwmyq03Q48TZB$MnE2Pmo`|4J>K|qsf2ADZi*&y>sTtH`
zgcG#o1~}93vpG(tHbJIM7d27<mK=qX6=WC`8Jfpy+B_$MtWa<&>Ss~Y;g1~`RAcQ1
z6(#w-bz8cbg=P#SG<0NSRAf|4L}K-42a-$7B^L25OH5?LeQ$2^$bIi;6>;V7W6HC^
zhxv2z!)0W!V+Y7@533S}kAfHDw_#;9tA4Q6qLcl^RqBN;suUJJMVm-Hx?4NAn+}g{
zK1BV_n@+Yc<PpQ)n2-P*B|*sT)ig2!)nxs&W^iU0BeDaEim19xEjL*5+{EsB{ar^C
zmZ!~GoM!#9O@bD^@;#J_eHl$l!HJ55l~Yl;5ZEaPe<I)zynZxD9AmW@9y{)Vj#qh@
z-Odv~z%Rv$JcmE}w5@IwlhKfEYGo&eZ2aRo8$*FpVvmpWz}{L0vJ$)0|K59EltAZ*
zh=6Jgb>o90byI|G;J4EXf`D85l{mgB{$JR?;=aC&dGU{>4TNic0e#d01+hgdP$wU^
zcY>MpA`HFEkY|R($Fb`U3ko-P6v;l)B&MWU#?}HjYHFt@j1l-jxWj*IYd8E?i@&Li
zuJ`y`*M5O|v*qA;eOV9Xl1eA^%6t5?x|M{D+)6jQq9c{#!+>Qkeoo@)=61w-{#{{o
zDLyWaUqHb3ZG;eF=Et*v9T@mM;TWHXqmS#Z=v!MLs1s?!oU_wi%JzLfUPXmcii$i2
z^RSRY<=lz9%yw)mPf{o=rE|XQ<fNm+L;eb^&H3ks?VFp(rbxk)+Zb-f*|sts^2uae
zh*jKVG1oOVoNkkWl6ud2D#uPgBBaMEn}CpWy_!Ntyn|_oU%XqR8S9J{LFh4@@giK3
zGzFo0Aq)@C@6BuLM<n7v)B{a#Zg)<bzx%{*<+phbvo2cc`ApLEFZ%cowl%Z3`5fHI
z(K|}3t;vGzoUB>V5LtNCI?n}F3ev)`DlT%IL!%hof=Ts7HQBvf?PV^;fC9Pa#k0m4
z0iVD6JFX>pIW9sid^x`xJhs-2!$YYE)mfh|Af?_y#0ONCv@-Yw)gAR%v=I6+)Zxfe
zZ^`l)`sT|+Evh{0%F9P#Nx%uxO&oo_e8;&7f%pLQL*M|?8y~QWU|4E`ATAMhE#-dO
zv1C7O%XKpi8wN|e%3$_I&7MpsirDxL&C$B@qIq{CBz-L%!J=!)?yu0~t|*vMpQlgO
z{1cg~IZ?$9ECKiM=G6f^lViao;%gCOYinJ(*QGB`Z{xkge&b-gQ1gq@N(g%zlkold
zww4RGYv&)!zlj-sCgSsUZ)KxQ#NF@n?mm;Z(CO=S*u_On(5(5ARFO(rioF-u6!R;m
z-aPhEGlI)Wpl2^IHJ;xGynN_tJ3b}X;$CSnMY7kacWUnLdbU;S-xfV2FQU5wd;42C
zPIfQsOI7$bC)9<ADfVyke<~2wdnbKAKEP_!!h{kmt|=S47gtDYYQ~T^R8bM>7hpYG
zlz*F)g1k>t`XksYBS%+CP{Ey4RI}IPda1}Urf)*4ftq2cwHG+%W>VFu7;#qNxYZ%#
znlV8}R^QxJlmadtQ)<$5Sp!yvk&#x+JBwX{>H46_@7-EGXMp<f<rnMmPBzq?bL^(o
zM^Wz)hz>k0t|X6?c_I}m6lCDQh%|_Wq<qi9kD$G9?1%C7YG>E7pZnbDaOSEZ{Qa1(
zpd{GG8=M>bx!l=@<!G4~NT@vfy~h<=bX*z@E(u1QgH@a8p`OpHH>oF~R*YmSO~1S_
zC6>fb%f*}0tdeFNWXn=PyvU3&vtEjXB%Bab+Rd>=w`srb0lNO1)_R<wDCp%OWb|xA
z^EXU7Nr1{J>YzMWFhYs%Zbe=RE7wLoP2KrX)$=J*zBeGHnyS|-{Vs5h2MHbhaC(}d
z=J@WzX`^$x5?gM86-h$OjheicqVrnZXUH&3!jtBABkcDuSR^r{z%;QGjZ#o@KeGGo
z<U(XY6OD9E?W2+-wYolqw1{0zJQPVl!LxUc`)T?Y6aqIlz-kFa$Mmy^J)JV;^zssy
z*1?vRL5YX5Q(?r1PUFXkN?mujI}ZU4!W;Herzkqu7w(@SqPG`~4SSmsuHsH!3bv8U
z0mCeZwGlT`745O&!2=PBUyNbm3JSF9*>1@=wf31jmag{sS=3!?W%c`i35#roAw>4~
zWct=gq_&#udL!parJql4W&NpZmY((^WuJ;bi12}!p7~Oz%OYv4Z{X5!C%P`7Y#7pX
zFEKqH6=7-KPUBn!7t0|XjOZ98{XHA)^p;(+yWnKWdXT(2E4EMy&+{keYd%b{&Dq}A
zxwCBk?o<CeDxQKa6qMS_3*L7?A96_=;O|CUb36kB1Lcp5AD0|?H~HTK()81AN5_R<
zxh{9WqQt~QX|8n;6N=+D^<{gHRo*s^;3I2Ti#S{L>#7~?dh~Qs{XobY82wh~kBrlN
ze84+V1R&<?k$!xG{oth3b)QyI5Mjh}+l3Vrcy8UAD(0h<0s!mWe_3{g%a)Y{JW1iD
z%UzUr5#aR<b<-95h?nzzsTd-?t9i@IM)th+07;0y#i_;hr(nQ9SJTii{nz3mJO@~F
z_LLW%sL29aL3+yB@<9=bUYk}HD&j01Sz*tphp_<sM6&pg(62(3x17cm1$c*bQ#>0b
zr5x<+928i$UIrogsj|q!-?QbBXXWa+odPX26FTu0A(YisRrR^gd{PSbeX5OI!4S4w
zk<|?j*uhK*7P7N#SbrTl_c11YTh`9fX>8-(G0>0^F~p+ckx5EV|H$P>JeTQ2O!f5W
zA!T5=G`uHqjm4HSs^KtW=D?ulv|U*F4G#n#K-$<lw?Qcx)^=mA-q2}GTwkj_BEOOJ
zjqSQ$=C~f3tAZF-P_yU)78dZ+ygGQ9Z5APKi&LC%txwHV+0L-z)ut}<<dFzg3oR}3
zm15%H{9K;W*3KKUEQv5nZ)f8DnyS6ME@vQKgP*%?<a?Cx6$R>r<eNw?MxXPR_`qyP
zNeOkI%L*C!1I$dxbQ7Y$@|wRweR@#kFf$4PLtal0t~OipSXL&pB0V;hw?rvX?3jk(
zqF}t_-#IJP@kF28rBH~WJJc)hAu6_OT{35e#aHH5)B@o9>jECg!}V?X>oS9N>0FQQ
zrQg9OM@6bAg$Jws@^zH$7w*#o9~#c+f|*Seqb7|lRsU_3q#r*<FHOWB8~n72+c#aU
zTw`ePLs^!@WD}~sP;EQQ3l|=R_MDt>t)&MrGP-)KUYvK|RYU60s1i{L<gH9iJ8HYk
z)*QD-vkW^iEIGbV3D+bLLE6Q~$D@Zza*VFoDJVQ-mX?)9*~pX@Nu<kdZ1n0X*X2>9
z?5aBC9OH!hMVLkH7Rd-49Hc)r7NaY>TKqY30*7EWwf(b}ZSWg0L&4gSxLA4hyc!mv
zHMXW};7c7h>z`=z;s$N1U*&^)*$#X&Yja7})v@x-f;JFXXU6t;b4!vYe>pnY36I|x
z!Hi=^ZJWSk2CvqgX~LgrdwCR>Oije)+2Ix5@#HQFk{hRHY$tzqAYly*4Ux!akc*8%
z%<ikMV#uQGcNUO*JR<OulLW;c{?JHUYVr`+L7P`j2RXywnW*Sc%o3qR53y3lYWK`E
zb6$9z6Z%R5pa%PX6S|-IE3BQ7#F);NiDBnJD;ndNhWhg|BGV#$6Ho{+$9HLCeY2jC
z+NSuL<z}iNkl7}mSyrZ9%!wxBDIjU(=vXCn2rqSQ0E8#$6fYrKwI#xwT3&kRmL`dN
zcY+*}Z95*PyLVrUPtAH1I+1ByuRE<fz7FM8wQaz$jPa~3-O-nuII;lb680hf`6!9i
zUPcbTiM+<%4$yn?tPg4=KJD9{%QiquYizub)!vhORY*jxn~vPv`t{5IVzZr%JWsNX
zmv_vJiUgg&mJ&Y{w4dK1O%YhfaDzjkT3Wgjz_;xVc4ndisR?PFajFz1;GRD_9~F0R
zH(1AFa?k9(A-OKK{>E>k&}il|nti(BY+KQ0vm0dtd?(fdo1|2P<~omUo%no*-)ni9
zZ@YG^EwV_|&kAemd9EHYIiI<EO8WdlS;Xr<zQOwbiafJ)Q(K9Q1;bnVb*}-fqx6+b
zf8g5K+HHM!k&sW9Y36Qt)F_I!^0B@q+N+1|u=uWA0Xz1*2gxY3I1ksP1uV0}!|cqy
zI7gp9K!8d(D5Mzp`69a%t?Y<w$IS<2H#krxrhlqi6oBBKTVq{8JEiix>eCQJzErP}
z7+uU-kDry@itDT}Zgz%OoSzgzl3UQ;szU|`tC}`C&!YE>JTFZ{Al?bzNx-G#S=&pZ
z5N_35&;!qr3iq^sXx;q@Jl)d4^sFv%tTu9wy9n_Ho#|&7Ibrxw>Y8Tuyv;_#mVu5=
z?US|P%N`)<cO9gMo#Uao{i^dX*R7RCd3JY1+%Z4{ICB<7l(~>-Ql_+2e=<VWR-#2~
z#HB`BT6(&M+idL^ystB?(;Ison{`=&eaE4s4?_2z{Ja%9Yq||EOI8m$3z$m{vkL=6
z3;r_*Hkv+|#YZWdl&&$c_R3FIZ*mFF21z&*(BfmJnV5{-EM2#QONGS+qZ5Oj9tXks
z6Mw>SS5(A(r!~@AZ_st85|gSvyNRx;M*ChZ&bETRn=_sC_(31*z+ASq<VB?YSDC`P
z8DDuQQwHqsC2EW&{=Q@LkuIzZc6k-bFH+{gEJ#MI3iX|lvK-&}ICcJnS>xYA5j~!7
zz+Z>95r=MK1&J5-92TeZ3%b?cJl9{4GQcLlhi$U4*St8lbI?cqP1(Zd>^6Jx;j`ax
zBeid(n5O%%*FAC|1;2iO^fTLuc*^WV4TlSyGxPZ(oj!W|ckPt&@K2}QUwGE5^rC*m
zQq2rK1HB)5oHLwA^kM_g;DW3Gm>czJ#{JogNO|<f!`C0hG;IYx%8ycBmS0$sABv?k
z-KR%sq4iG#opKSx3co)4y*w)B)Tr7&{tV<qHh!qqSlx~dsJUo9cYd2n7(bR(P?48x
zUb1ubu_)7v>IIo;_W~FJ^Dg6GCJi(BjjNK6YjH~xxza9vOb~g!o4Mv!P`6MP4{>zw
z3QOeamD+0q;b?H)VE;DzCQqhoc7SYb<=ptC;{xq!<+t-%y8qlaE~lhuZhQ%UZuh-0
zH0QKKc+s<wJa!mwqT3WQYNsg?4-1<K8v1!J{li`?Jw;Vt!$SIG|HX7%M|MJ|la_YE
zh1>{xSX^kk73{>Q+^;8*?$j{3r{!Kf%6@+<_%4DTGPBEfj}qitn~L1$3)xchji99_
z2Agl;!G5)&eh9QjmOZ^N;mbxRR(6Zmx>(Y?p2~#0aQJO+;^1InkN(O~Q$$6?u#%gM
zV&lZb+HXAV>Qy%Xup;y3&E4y!ZeTNpVO-<lMj5}2{!KedFT4aAfs(h07TTtD#0;Zk
zt1~C-)jL78$>uR%VA5Snb-E+a$fW{CSP;2BxjA>oze05R;I6jvp6{YVU|d)H1wqYC
zX<St;Xq>jHVoD>iiFPCZyfWMK23~DDkHEtAH2vAH{N$^uK_)o0VnG?l;%lz0VD+A*
zzdB&N3QJ0G2R$pNzU!x({!3dpr1IEkumm2jh`W}`3)^&s(1jsr>G&=7pC@;w7xZ#G
z|3ReXWgvL)j4?`0<ZB419sqyw!{SI=TN^<vbQ~?^4baDWBqK_Za@`w-clO6v0O9IL
zSc<%y)XbF~fpn3SIVB|p2oAO=Z;1e6GVb6;IePHC5RTM9T26t;_*H%>4TF~lK|)G;
zBccI|GD3!Ob=%)dsQH1cn$Ka-*Ee^JVC)JENl4h^he0a=GP7?&yE!1jqK1csx*%S|
z19T9v^E6c;tz+rWggSS9??Wfx6N+wm{%D*FX8=ekgkyQ|n<D|>*QhBe1cjl@)mJ<r
zitJ=5T)q<NTRX6<dgej5LKHK~71&9}2q$)h5SB4k4qm!s%t6lD;Iknp7<-rj<M!(h
zpNV#r`Q2K*oE)WG-lZ;gI=3WrmrYIqdVbf*)Uobi9*`#E!)p&}n5eLnE2q>Ks&qX+
zb7KdGo|}YsX0RA0q~*Jho^0&aQK+}Jj@Gj6$sQawJyy2Vhdc{e*{_TiD{UQyJS^7u
z9<0x6+ZZiO$W2N?6$uKz<tca(n4s&!H2z>((2WGirarxE?mDEAeoV*Tudz_#7qiwB
z761LabLM+@L|Pz~_;9{~O$_3EQ5I3xo!me3(E=qMYw6`398}Qy>BMP;15DgQBA}#1
zIo%R^dNQqg7J}!6{Lkthp7*5^Mb+M<GMJ1U$O~_SprE1U<cI~=AE}7&vgpU6LXaTD
z^m3F|m&N(F@`~w^UsF&ZuTECAKf)rQlx~J~I8Az7?A+L$zX9l-ahjxUB~yf>!U%9k
zqghj=LxtyYi#e+aKRDqr2z{71Ftf2BC+eare&&PBhmR<O2CMDay}Eu_{OPNtYFyL8
zqPxt@splmI3OL@t6ENadhl>@UM4i|G$zWfw;Opz^B*~J0)8@~4+69)@)}G(p#WrYV
zAwQ^Nb_D9!VvwMMGUtBh+OuYop|wP*1<!=QHsVq!%JcYLoZVS^@u+GuVq6^qZEXqd
z3-)^Y`#V$CmKw6JQZ@ZEdm_HfKAu&2VR;wOwq42bwP1q>>(}+8b6MkB;mX$<;8Pn0
zV>2Ee-+J-4q8J)7qEJw>;Ala=5{(#*t!jgRrg%DBz6!gjdLA#Gc11CaE71a)UfcQL
z)tX%XEUFi*K1p<!8VMg>%^+Fhq97tflx1fRef9SzvdmQgC;xr&yC5#C;9z~wtGXg9
zlQ(GYUi}smg#HCelqykcW}Jo1QSRo}653-Q%W}Aqnr19;H<_9{AA&F+7e`pCqYrHs
z{Mp)Rna4+Db??9eDi<&$rL0t5N<meIr0n5gWo706o-8@e?>^tR7eMWC=pVh>jqw<r
z2PXPnX($~bUZl+roy3NE1@@Wax#&k^BJS~qM>K<&0AOHZLK4bkOc~a}cSBRq@suj`
zerx~C24D9&1$^i&l%?nkt~~{%`;x+<6=q$ORhIn#6p!$}G=1=Z&A1DK4Jk0m6>=jM
z{SFt?oNELK!+_O<M!b?nCHX5xc1JLG(1B!lbpL#Je8(b7DGt=!gqJ~00&}jYgiRq=
z8iev1Z+d(xFgzLbPcZ<79c7_Wqipjn@LGQRknn^SO*n6BQ3yo!_)LQq?H<<+42xns
zLj}?gpjzTRugt*8yTtK>>9@D76pR;Sz_iEq&&{n<`Hval4BX_W;s8kc9<LPKL>3X6
zF?ZzbH=W@o@DoIk2sLkM-^{4Ko$yO<BZMdp|0qv3_w}@BXVRRXVMoh;-Ys{OCZFMQ
z>UVuIzJZgSn3#xxyZLVD@9gNvbd^pDX!Mk(Qzoz~Ll&Lk6^sg%k(opS*J6~8ZC~*@
zX`n#qFn|-vf^Mo8P=?urCp^H$E-NwHKO7R-ySS(;>v#&AN|hj+ce<olQ^XVT^yuh1
zwWO)u$G+Iq`M$s1TlHAu1%pQ9l?6WV9nKC8s0vK>ZC6%C`k04xWV1L`+NyPfpY?5M
z|8pE{@Ysf3zBf9J2u&?QUJiG2bJKJS(|VLCX5QE#lS_{+Z9`<${1}g);tZYH)#STd
zSFVJI_aN@muVsB48|g!eiEkwW0k5k|!VC^xrHBCoIdDTkx<%(Zx^;X7J?jx%Q4WR3
z0Fb{dNBo$Mk}_%3w!)i~Ff5$iP+DA*frpAS4{Z_Pr_Yj?lS4+f@76}bsPru-2^0I>
zBEwJNz-k*3LBgIOI_MNaQE=YBIQYsW!QY9j@ZEn`MguN(XrOSupJ!bi{ZKJmt|7Lx
z?Z=O{F?<xfq<n|78yXhmC%4q)Ib}ztRlNxCoFU<ruZ?Rl?jvvc;iAF9FwEP0m?;5G
zg=cc*(8`pNRLK?Fi^le4`y7YHaA{PyfS|nFpYt*<56fmSJw{8mP<F^ecr1X`4Pd;#
zyn+H`ok7FTFV3H}L{I<J0#twgNt&vS<QIW7?#$W3Lm}Yms<DebUGds%(7cvzWmz?r
zQcZIM-*`3@Kj*W~+|rWZBjVFhrtc7BiZ&o=M{;mo5Gg$)8|PF-<8;2L8!BuC{8Ql!
zPAp3fl!-g4SX-<mb@29m2pCsSf+ENkFZSMc_=TZUG-^dgoOnu~UC6sMG!!;I^x|?K
zf|F2jB95dYNAEoa3FB%b3lH~)j{DMr#10Kjg&IuxamjyPg{3y~amC8^u@Z7;F90`6
zxN-&HzVJPm&;z`$=3;|<i`~@;QeU*#nOo=t?@S3KojJ!0(NN~If~J)jJxu3yc|9F(
zJvS+`8&f34rpC5b7wC&x<G|x0_b@qjJwh;qzvA=ecdyCEGz^T-`hGg%Zpapia5K`P
zXlaRh*D%e!1%*ej>$FVR(wLR0G%_-01}O^zq&eDo|2eylkDZ}MbkgRq^+x3tOcgzb
zOLpmqwIeitcYohla(@T#f8-9$6eDEYujBDVdWs`$d&u9(c`;^A@WD}w+ZK9`Mj0z6
z&cl8Qn$sqe<fa{Kgs-oxl(8<SZ_!_mu#6Qis+S;PR+eCNP3B#N1V)#V%`cRinwoAi
z#)gj#u;lt`=LshX1QeB$S>pL1?06hZ;S!v$PcR}t6^~-ZC;1>Cip<+N{8R;|dG`qc
zv}O9apixC}f+C3=zP>iCVJN_b$6Kn6^kq<GfJ?JO&BauZS<Wx8B=0}r<k%06)Dxvn
zo%adu9A4jvr)mpO)FAN*9}NyA<b3V1d2BpAIx0x1t92V{aHeO^hC;#fiAy{kcoyCo
zNxEK}f?dG*7T|fuoB(DZXa`VAT_`&aT`7428h3Q8f?;q*prXu46k54(1lL;CS=28R
z*diPAc_4Ne!`NXbfmc+C@|6q_JFLi4WlMb3&CYaTv6rWXS=?5qT|ydwNm?_>q*6D|
zh=?F+p`PMSqJfi8Y6!MtVj=BMo-wkppKTyMeEAKrn)GyKdd3I`HMqR@>-mo4n`u(e
z?9srF>*9ppD_#%OzUq<FOY=~jEg>mYzD~{;br8wP=AEtOLzT220VMZBtU5jVaA_O^
zA!DgPg=_t`TT;)Y`DWA_CQb3vv%6n<juT6WO@j8$QswYb@=U_Bs8P_f!@n5Z&KUeR
z{FniQHk`tumo5ljPZ2DH!4^0Ly6f|mMiZ@h7mnZN3&dMF_;6_Jn^a?5tMfR-yXu^M
z!DyGe_Qp2-(sukgmq+o1$u{DBe``z5x!UCY9!^~{Y0HzbNQvt>r?+O$?x>?7>Ar+5
zC!}9KHDTUll=4wl7RJt*H0IMqKlAtV`w7^z$_Of|Y}=N*iPP?%8h(+~S{WhUgL+07
zIJspM`uT!<mX8E+Y&Vq7fa+b(RC-B#<>&#KRSMd3^STKZZP^(-Vsr7Gj;fo*!<tNt
zyPr3>{2M#GzP6UNTqNIU<h%Y{ATuNA({bv)l9<>Qt69f>qXxZ^R7~C`#}tLcUlLm@
z<vH}1rlq)8#OXx{@;!yu_Aw&kbz2m@UPVPy6T9agPk+|kEb;vbwBEj+S++pm6(=fJ
zC@eQ3Z-y_*c5eR$mZi{9IgZj*C@QN!V;C0?i-(=mDxB6dtWAy4;TJZgT-6MuQ&tv)
zLm-t<$*y&yOj1W7{UA}Giq(l%5yrv5XU@$PxGarJRYCY6#<@0h3oQ%7|HyMFuyc9d
z$(MZ=r0(hQP)Tz-qa2v;SW;kYcCe|esh82(&i*wrXb;U4hYMXO78R((k2`v>%iWH^
z!5JZ!+tjH37;J@$zqJ5CcLfDJGf82PGo>Wr?eFj;Q%UopnpXtD#=IkRP&D)fR{<w)
ztWhTMT@2pb&ay@mdx49}%t236kR5Mu75z8xe*VSC`K8o`Em0l?EUqr!=}5ZHLUA(K
zBufT_645)U^!1NZzo<U!4*uoO`(-%JJ4`8k#4Qql3Afu>?`@ZrTF5J2u8d<wr#Wn_
zzggF+%<wC<Q`M|7Nuc~|?~W0F2BGieWLt%l2XR<UkECD32kB_7<$l3&SuVT4@o>8$
z7|V=dAM?Pz?r)gxtUuh_<K86jZF0rk^a#YMjlC~KKSsZ1{yLWb>jK-{Ermi*s63YH
zOoPFjCR)xcE6Z9@)$WPnt2rmhN^1$;bxi9c@JQ6_=l$Z=2nqn7vlO=7;lftqEU>b7
zP`y;QAKt~$3fdMRwQyyrbjoWZ*_-lZTib@b_G^8w>6^xC_zs9hXLyZy@4f?i94Vhg
z`!<fL<rfws7P5UgcjNubx}Gxe)A_HG9=jyfeT{aE@9p$2^Y|s@nY}%J4vjAvxPFkB
zu+lflki2<@Mj3R?=MxFo45cSggj-0j#-*|V9N4_LY5%XI+<&_k)f1co^v}|ov^_{N
z&xe_5u)m`O!+YC#yj89aX=|RX{lJYLt*>BZWtEj3qhtgoyA&>jk`(1$%ouJxvqG!0
z;rmd(r(?L^U<Awv-*`p{R#aVvcsSNg2J@R1#63xeLVM=BCA9wxQW=Y;`mQ=hfh=5x
zHsGDb#fSBmw_h2uKgA9#Aq?fF%kc9-rvYeb)Shz9*4LX}QKwotI{(#ARcU@B?6X#O
zrA|k$;I5j<zLAC_264}th?k%u_pQJIvl$=Li)m8otFf-n6!^?Ql0WQs#pBf>AY)oU
zys`^7JnJTs5R};PJSWaN88C?;PdnmaDM=a!1zoNcbpbaG+hGcl94!OhJ%Vrc24f;U
zn_Ar}JZzz$!0y;;Y1zJn{$^u+&i~oNmc|vEiS2g>$XR~m>#$2Zjz>~vW)L}pVN~0O
zkWxHP3etDfsNc>^j;A<NGN|%o_sp~CR;jD=CS_Vx>TZj0=K3X?K7z4btqW^>3qpOp
zTOSwMqH{g(q$a2*3+opi_FD%d5&FH04&iWLu~Dw?Oh>ut`A!!_rZ|$ly<Au?g2E_{
z5^=&VAxV+HAad}|bwtNa3ChInR%UJXN%8T{{dPIRpj{6rF?wS24(z>(JY0I)s2wqK
zs4lnwlPS|!tHWJv_E^z8kB}JPNDm0hMdTqBB*hvX9_C3Egx|)B7T~n+-zWR51WFF~
zykOM&Gvu7d%$jn>t}qXVw-0sCx)1l4)<ELj841Jw`cUZ$vM1uYO@IV?5-#3M4UIi3
zo*tf!hepJExRY}N0XkqnK8m4|<*UbnM=vvp8g%ZEjOR--6Zp&wc*1$<FvRF2#LSw@
zdj1vq(bJAP+~1QOTHLBw^)zV049BVBvYU>Uvd1>q<OyqP<WPD$t$5wpOuB<i5?_;)
zcc$5Sb<Zg?<9e1p+$5@Je!-6lzIS1>y|xNZ2tzL7cugWy?lA5^(SCVm2*j-lF52V@
z+T%x*`0$QnzCi=sQ)sQE))$@5i!5n_%E;WVC-CQKJ}4QyFA?w54K&f~&R7^d6jIU6
zPj`1xfXC^L*Jscf-{V`m$+~`0;&)~W=mb49C_HNA&mUfMHzy)W1G*D==8R-$N%7Zr
zbF6;+e6*#WbR$n3w-0m&PQ^MyQ7YqO`kFbBryEFO%AgS@5>jnOMe3u_t_d?%4X*TH
z{5+BTylYAX%v=|+#TsxTno;spmmLhP@5DYGb;_LLVILP@C>fFS;v)~!tu~=`PTn(w
z@kq2sccr}peszs_a|jf~@0}a(6)VWFA|VbDn}oBIbW&_Bdy?$OI#a2_7$wSqVNMW8
zQ7moec)LT|o}Km&ELgd(qU71jCs@!EQ?R)buGTAc`(&6qv-!Bwc!oQ3r~BS{UR<7w
zzki8DO>^bD?$zuVE?6~FS0Elv9U$D^?!mf^V8)z$rNjVY<Ergxa#z~C8&<4`*1c=F
z)9>%ID;{EdFzTiE1K=;e9Qk<?4tmEtSmd;9{Kew`eW;$OnB(4&+(Y`SD4?Z%S$iX{
zNMifNM>gXl#UrL)nNm{m6wV0io`SMJnp7jViK_}}T?)OW`2<^`_|QGc(qUi8*gRgx
z{-!?xiX#<PMWk}R905W)-@B~$<z=LxMHZvK#=3z<t0n0axs^62t=gT2#}h&5&I9Y-
zFUQT^yuG3CH_o=#4$p@cj@ZDdedtYVaG~q3U$av48WI@iKP;XBjc}s=(pEn!3dMem
zb5ROivfc6J?K5y_Nr+rYuuNP1&?U{U3K`Wt>CoA7{3v@;VAO`^mfBIAxo(5^u@`?-
z)!O(Kd=k9Yde7M2WlPxo!YWbUs9DH}eX_B<*m^qYN+4D&rZb3)BF-KJ&P71fPk}$O
zJEdAJIYUf+tAU{x<D#`);C5(|^X6Xb!(_EdOvOseG_Hm<dAk?0@|lC=h!<tbSg~HQ
zfiN|F!gRN{HJG@nt*KcXR)}YC(!y@vtv%ofYt6>4?>CGnbMGE@jD1gHO+dQh(lR=O
z91<c)iJMrW9HyMkt`%WGTVh}9FzVJlW&Y6LO~Emu>6my<lCe%xwteIEIfsW;!#4^R
z;hpF+o9;ROko<KI4QGz-ioD6iLrPM6A|Z###*cwZtY%=Op#eeM3gYLF=qUBQPZ4bd
zwnQ93Oaaf!S#mmBZf;D_wc}vnQlZ_mFR<KK^WrYY#iQA)Y8`lGWkju;=ZwtGuINlq
z?-g1&@w2G{lW@EiD)3Ant3-Qc6b;wYIBzKReSbAc6wED6dv1L^UJ9nnqGF<=Vq$fO
zVL=9lVKG)YvMv|RyLM;eD#CAVw7bqR5}ECc9`aIv*ztH!;GPlD3qUPENJxJlsj)B5
f6#07~#Se&Sk-?3tS&oo@%Ijq$6vgXAjYIwqf?o_r

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/gregbook/wpng.c b/extern/libpng/contrib/gregbook/wpng.c
new file mode 100644
index 0000000000..a8f367fb84
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/wpng.c
@@ -0,0 +1,865 @@
+/*---------------------------------------------------------------------------
+
+   wpng - simple PNG-writing program                                 wpng.c
+
+   This program converts certain NetPBM binary files (grayscale and RGB,
+   maxval = 255) to PNG.  Non-interlaced PNGs are written progressively;
+   interlaced PNGs are read and written in one memory-intensive blast.
+
+   Thanks to Jean-loup Gailly for providing the necessary trick to read
+   interactive text from the keyboard while stdin is redirected.  Thanks
+   to Cosmin Truta for Cygwin fixes.
+
+   NOTE:  includes provisional support for PNM type "8" (portable alphamap)
+          images, presumed to be a 32-bit interleaved RGBA format; no pro-
+          vision for possible interleaved grayscale+alpha (16-bit) format.
+          THIS IS UNLIKELY TO BECOME AN OFFICIAL NETPBM ALPHA FORMAT!
+
+   to do:
+    - delete output file if quit before calling any writepng routines
+    - process backspace with -text option under DOS/Win? (currently get ^H)
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options
+    - 1.03:  removed extraneous character from usage screen; fixed bug in
+              command-line parsing
+    - 1.04:  fixed DOS/OS2/Win32 detection, including partial Cygwin fix
+              (see http://home.att.net/~perlspinr/diffs/GregBook_cygwin.diff)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  check for integer overflow (Glenn R-P)
+
+        [REPORTED BUG (win32 only):  "contrib/gregbook/wpng.c - cmd line
+         dose not work!  In order to do something useful I needed to redirect
+         both input and output, with cygwin and with bcc32 as well.  Under
+         Linux, the same wpng appears to work fine.  I don't know what is
+         the problem."]
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "wpng"
+#define VERSION   "2.00 of 2 June 2007"
+#define APPNAME   "Simple PGM/PPM/PAM to PNG Converter"
+
+#if defined(__MSDOS__) || defined(__OS2__)
+#  define DOS_OS2_W32
+#elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
+#  ifndef __GNUC__   /* treat Win32 native ports of gcc as Unix environments */
+#    define DOS_OS2_W32
+#  endif
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <setjmp.h>     /* for jmpbuf declaration in writepng.h */
+#include <time.h>
+
+#ifdef DOS_OS2_W32
+#  include <io.h>       /* for isatty(), setmode() prototypes */
+#  include <fcntl.h>    /* O_BINARY for fdopen() without text translation */
+#  ifdef __EMX__
+#    ifndef getch
+#      define getch() _read_kbd(0, 1, 0)    /* need getche() */
+#    endif
+#  else /* !__EMX__ */
+#    ifdef __GO32__
+#      include <pc.h>
+#      define getch() getkey()  /* GRR:  need getche() */
+#    else
+#      include <conio.h>        /* for getche() console input */
+#    endif
+#  endif /* ?__EMX__ */
+#  define FGETS(buf,len,stream)  dos_kbd_gets(buf,len)
+#else
+#  include <unistd.h>           /* for isatty() prototype */
+#  define FGETS fgets
+#endif
+
+/* #define DEBUG  :  this enables the Trace() macros */
+
+/* #define FORBID_LATIN1_CTRL  :  this requires the user to re-enter any
+   text that includes control characters discouraged by the PNG spec; text
+   that includes an escape character (27) must be re-entered regardless */
+
+#include "writepng.h"   /* typedefs, common macros, writepng prototypes */
+
+
+
+/* local prototypes */
+
+static int  wpng_isvalid_latin1(uch *p, int len);
+static void wpng_cleanup(void);
+
+#ifdef DOS_OS2_W32
+   static char *dos_kbd_gets(char *buf, int len);
+#endif
+
+
+
+static mainprog_info wpng_info;   /* lone global */
+
+
+
+int main(int argc, char **argv)
+{
+#ifndef DOS_OS2_W32
+    FILE *keybd;
+#endif
+#ifdef sgi
+    FILE *tmpfile;      /* or we could just use keybd, since no overlap */
+    char tmpline[80];
+#endif
+    char *inname = NULL, outname[256];
+    char *p, pnmchar, pnmline[256];
+    char *bgstr, *textbuf = NULL;
+    ulg rowbytes;
+    int rc, len = 0;
+    int error = 0;
+    int text = FALSE;
+    int maxval;
+    double LUT_exponent;                /* just the lookup table */
+    double CRT_exponent = 2.2;          /* just the monitor */
+    double default_display_exponent;    /* whole display system */
+    double default_gamma = 0.0;
+
+
+    wpng_info.infile = NULL;
+    wpng_info.outfile = NULL;
+    wpng_info.image_data = NULL;
+    wpng_info.row_pointers = NULL;
+    wpng_info.filter = FALSE;
+    wpng_info.interlaced = FALSE;
+    wpng_info.have_bg = FALSE;
+    wpng_info.have_time = FALSE;
+    wpng_info.have_text = 0;
+    wpng_info.gamma = 0.0;
+
+
+    /* First get the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  If the PNM image
+     * looks correct on the user's display system, its file gamma is the
+     * inverse of this value.  (Note that this is not an exhaustive list
+     * of LUT values--e.g., OpenStep has a lot of weird ones--but it should
+     * cover 99% of the current possibilities.  This section must ensure
+     * that default_display_exponent is positive.) */
+
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    tmpfile = fopen("/etc/config/system.glGammaVal", "r");
+    if (tmpfile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, tmpfile);
+        fclose(tmpfile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL) {
+        double exponent = atof(p);
+
+        if (exponent > 0.0)
+            default_gamma = 1.0 / exponent;
+    }
+
+    if (default_gamma == 0.0)
+        default_gamma = 1.0 / default_display_exponent;
+
+
+    /* Now parse the command line for options and the PNM filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-i", 2)) {
+            wpng_info.interlaced = TRUE;
+        } else if (!strncmp(*argv, "-time", 3)) {
+            wpng_info.modtime = time(NULL);
+            wpng_info.have_time = TRUE;
+        } else if (!strncmp(*argv, "-text", 3)) {
+            text = TRUE;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                wpng_info.gamma = atof(*argv);
+                if (wpng_info.gamma <= 0.0)
+                    ++error;
+                else if (wpng_info.gamma > 1.01)
+                    fprintf(stderr, PROGNAME
+                      " warning:  file gammas are usually less than 1.0\n");
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    unsigned r, g, b;  /* this way quiets compiler warnings */
+
+                    sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+                    wpng_info.bg_red   = (uch)r;
+                    wpng_info.bg_green = (uch)g;
+                    wpng_info.bg_blue  = (uch)b;
+                    wpng_info.have_bg = TRUE;
+                }
+            }
+        } else {
+            if (**argv != '-') {
+                inname = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+
+    /* open the input and output files, or register an error and abort */
+
+    if (!inname) {
+        if (isatty(0)) {
+            fprintf(stderr, PROGNAME
+              ":  must give input filename or provide image data via stdin\n");
+            ++error;
+        } else {
+#ifdef DOS_OS2_W32
+            /* some buggy C libraries require BOTH setmode() and fdopen(bin) */
+            setmode(fileno(stdin), O_BINARY);
+            setmode(fileno(stdout), O_BINARY);
+#endif
+            if ((wpng_info.infile = fdopen(fileno(stdin), "rb")) == NULL) {
+                fprintf(stderr, PROGNAME
+                  ":  unable to reopen stdin in binary mode\n");
+                ++error;
+            } else
+            if ((wpng_info.outfile = fdopen(fileno(stdout), "wb")) == NULL) {
+                fprintf(stderr, PROGNAME
+                  ":  unable to reopen stdout in binary mode\n");
+                fclose(wpng_info.infile);
+                ++error;
+            } else
+                wpng_info.filter = TRUE;
+        }
+    } else if ((len = strlen(inname)) > 250) {
+        fprintf(stderr, PROGNAME ":  input filename is too long [%d chars]\n",
+          len);
+        ++error;
+    } else if (!(wpng_info.infile = fopen(inname, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open input file [%s]\n", inname);
+        ++error;
+    }
+
+    if (!error) {
+        fgets(pnmline, 256, wpng_info.infile);
+        if (pnmline[0] != 'P' || ((pnmchar = pnmline[1]) != '5' &&
+            pnmchar != '6' && pnmchar != '8'))
+        {
+            fprintf(stderr, PROGNAME
+              ":  input file [%s] is not a binary PGM, PPM or PAM file\n",
+              inname);
+            ++error;
+        } else {
+            wpng_info.pnmtype = (int)(pnmchar - '0');
+            if (wpng_info.pnmtype != 8)
+                wpng_info.have_bg = FALSE;  /* no need for bg if opaque */
+            do {
+                fgets(pnmline, 256, wpng_info.infile);  /* lose any comments */
+            } while (pnmline[0] == '#');
+            sscanf(pnmline, "%ld %ld", &wpng_info.width, &wpng_info.height);
+            do {
+                fgets(pnmline, 256, wpng_info.infile);  /* more comment lines */
+            } while (pnmline[0] == '#');
+            sscanf(pnmline, "%d", &maxval);
+            if (wpng_info.width <= 0L || wpng_info.height <= 0L ||
+                maxval != 255)
+            {
+                fprintf(stderr, PROGNAME
+                  ":  only positive width/height, maxval == 255 allowed \n");
+                ++error;
+            }
+            wpng_info.sample_depth = 8;  /* <==> maxval 255 */
+
+            if (!wpng_info.filter) {
+                /* make outname from inname */
+                if ((p = strrchr(inname, '.')) == NULL ||
+                    (p - inname) != (len - 4))
+                {
+                    strcpy(outname, inname);
+                    strcpy(outname+len, ".png");
+                } else {
+                    len -= 4;
+                    strncpy(outname, inname, len);
+                    strcpy(outname+len, ".png");
+                }
+                /* check if outname already exists; if not, open */
+                if ((wpng_info.outfile = fopen(outname, "rb")) != NULL) {
+                    fprintf(stderr, PROGNAME ":  output file exists [%s]\n",
+                      outname);
+                    fclose(wpng_info.outfile);
+                    ++error;
+                } else if (!(wpng_info.outfile = fopen(outname, "wb"))) {
+                    fprintf(stderr, PROGNAME ":  can't open output file [%s]\n",
+                      outname);
+                    ++error;
+                }
+            }
+        }
+        if (error) {
+            fclose(wpng_info.infile);
+            wpng_info.infile = NULL;
+            if (wpng_info.filter) {
+                fclose(wpng_info.outfile);
+                wpng_info.outfile = NULL;
+            }
+        }
+    }
+
+
+    /* if we had any errors, print usage and die horrible death...arrr! */
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, APPNAME);
+        writepng_version_info();
+        fprintf(stderr, "\n"
+"Usage:  %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] pnmfile\n"
+"or: ... | %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] | ...\n"
+         "    exp \ttransfer-function exponent (``gamma'') of the image in\n"
+         "\t\t  floating-point format (e.g., ``%.5f''); if image looks\n"
+         "\t\t  correct on given display system, image gamma is equal to\n"
+         "\t\t  inverse of display-system exponent, i.e., 1 / (LUT * CRT)\n"
+         "\t\t  (where LUT = lookup-table exponent and CRT = CRT exponent;\n"
+         "\t\t  first varies, second is usually 2.2, all are positive)\n"
+         "    bg  \tdesired background color for alpha-channel images, in\n"
+         "\t\t  7-character hex RGB format (e.g., ``#ff7700'' for orange:\n"
+         "\t\t  same as HTML colors)\n"
+         "    -text\tprompt interactively for text info (tEXt chunks)\n"
+         "    -time\tinclude a tIME chunk (last modification time)\n"
+         "    -interlace\twrite interlaced PNG image\n"
+         "\n"
+"pnmfile or stdin must be a binary PGM (`P5'), PPM (`P6') or (extremely\n"
+"unofficial and unsupported!) PAM (`P8') file.  Currently it is required\n"
+"to have maxval == 255 (i.e., no scaling).  If pnmfile is specified, it\n"
+"is converted to the corresponding PNG file with the same base name but a\n"
+"``.png'' extension; files read from stdin are converted and sent to stdout.\n"
+"The conversion is progressive (low memory usage) unless interlacing is\n"
+"requested; in that case the whole image will be buffered in memory and\n"
+"written in one call.\n"
+         "\n", PROGNAME, PROGNAME, default_gamma);
+        exit(1);
+    }
+
+
+    /* prepare the text buffers for libpng's use; note that even though
+     * PNG's png_text struct includes a length field, we don't have to fill
+     * it out */
+
+    if (text &&
+#ifndef DOS_OS2_W32
+        (keybd = fdopen(fileno(stderr), "r")) != NULL &&
+#endif
+        (textbuf = (char *)malloc((5 + 9)*75)) != NULL)
+    {
+        int i, valid, result;
+
+        fprintf(stderr,
+          "Enter text info (no more than 72 characters per line);\n");
+        fprintf(stderr, "to skip a field, hit the <Enter> key.\n");
+        /* note:  just <Enter> leaves len == 1 */
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_TITLE_OFFSET;
+            fprintf(stderr, "  Title: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.title = p;
+                wpng_info.have_text |= TEXT_TITLE;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_TITLE;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_TITLE;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_AUTHOR_OFFSET;
+            fprintf(stderr, "  Author: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.author = p;
+                wpng_info.have_text |= TEXT_AUTHOR;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_AUTHOR;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_AUTHOR;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_DESC_OFFSET;
+            fprintf(stderr, "  Description (up to 9 lines):\n");
+            for (i = 1;  i < 10;  ++i) {
+                fprintf(stderr, "    [%d] ", i);
+                fflush(stderr);
+                if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1)
+                    p += len;   /* now points at NULL; char before is newline */
+                else
+                    break;
+            }
+            if ((len = p - (textbuf + TEXT_DESC_OFFSET)) > 1) {
+                if (p[-1] == '\n') {
+                    p[-1] = '\0';
+                    --len;
+                }
+                wpng_info.desc = textbuf + TEXT_DESC_OFFSET;
+                wpng_info.have_text |= TEXT_DESC;
+                p = textbuf + TEXT_DESC_OFFSET;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_DESC;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_DESC;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_COPY_OFFSET;
+            fprintf(stderr, "  Copyright: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.copyright = p;
+                wpng_info.have_text |= TEXT_COPY;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_COPY;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_COPY;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_EMAIL_OFFSET;
+            fprintf(stderr, "  E-mail: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.email = p;
+                wpng_info.have_text |= TEXT_EMAIL;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_EMAIL;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_EMAIL;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_URL_OFFSET;
+            fprintf(stderr, "  URL: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.url = p;
+                wpng_info.have_text |= TEXT_URL;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_URL;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_URL;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+#ifndef DOS_OS2_W32
+        fclose(keybd);
+#endif
+
+    } else if (text) {
+        fprintf(stderr, PROGNAME ":  unable to allocate memory for text\n");
+        text = FALSE;
+        wpng_info.have_text = 0;
+    }
+
+
+    /* allocate libpng stuff, initialize transformations, write pre-IDAT data */
+
+    if ((rc = writepng_init(&wpng_info)) != 0) {
+        switch (rc) {
+            case 2:
+                fprintf(stderr, PROGNAME
+                  ":  libpng initialization problem (longjmp)\n");
+                break;
+            case 4:
+                fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                break;
+            case 11:
+                fprintf(stderr, PROGNAME
+                  ":  internal logic error (unexpected PNM type)\n");
+                break;
+            default:
+                fprintf(stderr, PROGNAME
+                  ":  unknown writepng_init() error\n");
+                break;
+        }
+        exit(rc);
+    }
+
+
+    /* free textbuf, since it's a completely local variable and all text info
+     * has just been written to the PNG file */
+
+    if (text && textbuf) {
+        free(textbuf);
+        textbuf = NULL;
+    }
+
+
+    /* calculate rowbytes on basis of image type; note that this becomes much
+     * more complicated if we choose to support PBM type, ASCII PNM types, or
+     * 16-bit-per-sample binary data [currently not an official NetPBM type] */
+
+    if (wpng_info.pnmtype == 5)
+        rowbytes = wpng_info.width;
+    else if (wpng_info.pnmtype == 6)
+        rowbytes = wpng_info.width * 3;
+    else /* if (wpng_info.pnmtype == 8) */
+        rowbytes = wpng_info.width * 4;
+
+
+    /* read and write the image, either in its entirety (if writing interlaced
+     * PNG) or row by row (if non-interlaced) */
+
+    fprintf(stderr, "Encoding image data...\n");
+    fflush(stderr);
+
+    if (wpng_info.interlaced) {
+        long i;
+        ulg bytes;
+        ulg image_bytes;
+
+        /* Guard against integer overflow */
+        if (wpng_info_height > ((size_t)(-1)/rowbytes ||
+            wpng_info_height > ((ulg)(-1)/rowbytes) {
+            fprintf(stderr, PROGNAME ":  image_data buffer too large\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+
+        image_bytes = rowbytes * wpng_info.height;
+
+        wpng_info.image_data = (uch *)malloc(image_bytes);
+        wpng_info.row_pointers = (uch **)malloc(wpng_info.height*sizeof(uch *));
+        if (wpng_info.image_data == NULL || wpng_info.row_pointers == NULL) {
+            fprintf(stderr, PROGNAME ":  insufficient memory for image data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+        for (i = 0;  i < wpng_info.height;  ++i)
+            wpng_info.row_pointers[i] = wpng_info.image_data + i*rowbytes;
+        bytes = fread(wpng_info.image_data, 1, image_bytes, wpng_info.infile);
+        if (bytes != image_bytes) {
+            fprintf(stderr, PROGNAME ":  expected %lu bytes, got %lu bytes\n",
+              image_bytes, bytes);
+            fprintf(stderr, "  (continuing anyway)\n");
+        }
+        if (writepng_encode_image(&wpng_info) != 0) {
+            fprintf(stderr, PROGNAME
+              ":  libpng problem (longjmp) while writing image data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+
+    } else /* not interlaced:  write progressively (row by row) */ {
+        long j;
+        ulg bytes;
+
+        wpng_info.image_data = (uch *)malloc(rowbytes);
+        if (wpng_info.image_data == NULL) {
+            fprintf(stderr, PROGNAME ":  insufficient memory for row data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+        error = 0;
+        for (j = wpng_info.height;  j > 0L;  --j) {
+            bytes = fread(wpng_info.image_data, 1, rowbytes, wpng_info.infile);
+            if (bytes != rowbytes) {
+                fprintf(stderr, PROGNAME
+                  ":  expected %lu bytes, got %lu bytes (row %ld)\n", rowbytes,
+                  bytes, wpng_info.height-j);
+                ++error;
+                break;
+            }
+            if (writepng_encode_row(&wpng_info) != 0) {
+                fprintf(stderr, PROGNAME
+                  ":  libpng problem (longjmp) while writing row %ld\n",
+                  wpng_info.height-j);
+                ++error;
+                break;
+            }
+        }
+        if (error) {
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+        if (writepng_encode_finish(&wpng_info) != 0) {
+            fprintf(stderr, PROGNAME ":  error on final libpng call\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+    }
+
+
+    /* OK, we're done (successfully):  clean up all resources and quit */
+
+    fprintf(stderr, "Done.\n");
+    fflush(stderr);
+
+    writepng_cleanup(&wpng_info);
+    wpng_cleanup();
+
+    return 0;
+}
+
+
+
+
+
+static int wpng_isvalid_latin1(uch *p, int len)
+{
+    int i, result = -1;
+
+    for (i = 0;  i < len;  ++i) {
+        if (p[i] == 10 || (p[i] > 31 && p[i] < 127) || p[i] > 160)
+            continue;           /* character is completely OK */
+        if (result < 0 || (p[result] != 27 && p[i] == 27))
+            result = i;         /* mark location of first questionable one */
+    }                           /*  or of first escape character (bad) */
+
+    return result;
+}
+
+
+
+
+
+static void wpng_cleanup(void)
+{
+    if (wpng_info.outfile) {
+        fclose(wpng_info.outfile);
+        wpng_info.outfile = NULL;
+    }
+
+    if (wpng_info.infile) {
+        fclose(wpng_info.infile);
+        wpng_info.infile = NULL;
+    }
+
+    if (wpng_info.image_data) {
+        free(wpng_info.image_data);
+        wpng_info.image_data = NULL;
+    }
+
+    if (wpng_info.row_pointers) {
+        free(wpng_info.row_pointers);
+        wpng_info.row_pointers = NULL;
+    }
+}
+
+
+
+
+#ifdef DOS_OS2_W32
+
+static char *dos_kbd_gets(char *buf, int len)
+{
+    int ch, count=0;
+
+    do {
+        buf[count++] = ch = getche();
+    } while (ch != '\r' && count < len-1);
+
+    buf[count--] = '\0';        /* terminate string */
+    if (buf[count] == '\r')     /* Enter key makes CR, so change to newline */
+        buf[count] = '\n';
+
+    fprintf(stderr, "\n");      /* Enter key does *not* cause a newline */
+    fflush(stderr);
+
+    return buf;
+}
+
+#endif /* DOS_OS2_W32 */
diff --git a/extern/libpng/contrib/gregbook/writepng.c b/extern/libpng/contrib/gregbook/writepng.c
new file mode 100644
index 0000000000..055c74374a
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/writepng.c
@@ -0,0 +1,401 @@
+/*---------------------------------------------------------------------------
+
+   wpng - simple PNG-writing program                             writepng.c
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+
+#include <stdlib.h>     /* for exit() prototype */
+#include <zlib.h>
+
+#include "png.h"        /* libpng header, includes setjmp.h */
+#include "writepng.h"   /* typedefs, common macros, public prototypes */
+
+
+/* local prototype */
+
+static void writepng_error_handler(png_structp png_ptr, png_const_charp msg);
+
+
+
+void writepng_version_info(void)
+{
+  fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
+    PNG_LIBPNG_VER_STRING, png_libpng_ver);
+  fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
+    ZLIB_VERSION, zlib_version);
+}
+
+
+
+
+/* returns 0 for success, 2 for libpng problem, 4 for out of memory, 11 for
+ *  unexpected pnmtype; note that outfile might be stdout */
+
+int writepng_init(mainprog_info *mainprog_ptr)
+{
+    png_structp  png_ptr;       /* note:  temporary variables! */
+    png_infop  info_ptr;
+    int color_type, interlace_type;
+
+
+    /* could also replace libpng warning-handler (final NULL), but no need: */
+
+    png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), mainprog_ptr,
+      writepng_error_handler, NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_write_struct(&png_ptr, NULL);
+        return 4;   /* out of memory */
+    }
+
+
+    /* setjmp() must be called in every function that calls a PNG-writing
+     * libpng function, unless an alternate error handler was installed--
+     * but compatible error handlers must either use longjmp() themselves
+     * (as in this program) or some other method to return control to
+     * application code, so here we go: */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return 2;
+    }
+
+
+    /* make sure outfile is (re)opened in BINARY mode */
+
+    png_init_io(png_ptr, mainprog_ptr->outfile);
+
+
+    /* set the compression levels--in general, always want to leave filtering
+     * turned on (except for palette images) and allow all of the filters,
+     * which is the default; want 32K zlib window, unless entire image buffer
+     * is 16K or smaller (unknown here)--also the default; usually want max
+     * compression (NOT the default); and remaining compression flags should
+     * be left alone */
+
+    png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
+/*
+    >> this is default for no filtering; Z_FILTERED is default otherwise:
+    png_set_compression_strategy(png_ptr, Z_DEFAULT_STRATEGY);
+    >> these are all defaults:
+    png_set_compression_mem_level(png_ptr, 8);
+    png_set_compression_window_bits(png_ptr, 15);
+    png_set_compression_method(png_ptr, 8);
+ */
+
+
+    /* set the image parameters appropriately */
+
+    if (mainprog_ptr->pnmtype == 5)
+        color_type = PNG_COLOR_TYPE_GRAY;
+    else if (mainprog_ptr->pnmtype == 6)
+        color_type = PNG_COLOR_TYPE_RGB;
+    else if (mainprog_ptr->pnmtype == 8)
+        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+    else {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return 11;
+    }
+
+    interlace_type = mainprog_ptr->interlaced? PNG_INTERLACE_ADAM7 :
+                                               PNG_INTERLACE_NONE;
+
+    png_set_IHDR(png_ptr, info_ptr, mainprog_ptr->width, mainprog_ptr->height,
+      mainprog_ptr->sample_depth, color_type, interlace_type,
+      PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+    if (mainprog_ptr->gamma > 0.0)
+        png_set_gAMA(png_ptr, info_ptr, mainprog_ptr->gamma);
+
+    if (mainprog_ptr->have_bg) {   /* we know it's RGBA, not gray+alpha */
+        png_color_16  background;
+
+        background.red = mainprog_ptr->bg_red;
+        background.green = mainprog_ptr->bg_green;
+        background.blue = mainprog_ptr->bg_blue;
+        png_set_bKGD(png_ptr, info_ptr, &background);
+    }
+
+    if (mainprog_ptr->have_time) {
+        png_time  modtime;
+
+        png_convert_from_time_t(&modtime, mainprog_ptr->modtime);
+        png_set_tIME(png_ptr, info_ptr, &modtime);
+    }
+
+    if (mainprog_ptr->have_text) {
+        png_text  text[6];
+        int  num_text = 0;
+
+        if (mainprog_ptr->have_text & TEXT_TITLE) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Title";
+            text[num_text].text = mainprog_ptr->title;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_AUTHOR) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Author";
+            text[num_text].text = mainprog_ptr->author;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_DESC) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Description";
+            text[num_text].text = mainprog_ptr->desc;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_COPY) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Copyright";
+            text[num_text].text = mainprog_ptr->copyright;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_EMAIL) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "E-mail";
+            text[num_text].text = mainprog_ptr->email;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_URL) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "URL";
+            text[num_text].text = mainprog_ptr->url;
+            ++num_text;
+        }
+        png_set_text(png_ptr, info_ptr, text, num_text);
+    }
+
+
+    /* write all chunks up to (but not including) first IDAT */
+
+    png_write_info(png_ptr, info_ptr);
+
+
+    /* if we wanted to write any more text info *after* the image data, we
+     * would set up text struct(s) here and call png_set_text() again, with
+     * just the new data; png_set_tIME() could also go here, but it would
+     * have no effect since we already called it above (only one tIME chunk
+     * allowed) */
+
+
+    /* set up the transformations:  for now, just pack low-bit-depth pixels
+     * into bytes (one, two or four pixels per byte) */
+
+    png_set_packing(png_ptr);
+/*  png_set_shift(png_ptr, &sig_bit);  to scale low-bit-depth values */
+
+
+    /* make sure we save our pointers for use in writepng_encode_image() */
+
+    mainprog_ptr->png_ptr = png_ptr;
+    mainprog_ptr->info_ptr = info_ptr;
+
+
+    /* OK, that's all we need to do for now; return happy */
+
+    return 0;
+}
+
+
+
+
+
+/* returns 0 for success, 2 for libpng (longjmp) problem */
+
+int writepng_encode_image(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* and now we just write the whole image; libpng takes care of interlacing
+     * for us */
+
+    png_write_image(png_ptr, mainprog_ptr->row_pointers);
+
+
+    /* since that's it, we also close out the end of the PNG file now--if we
+     * had any text or time info to write after the IDATs, second argument
+     * would be info_ptr, but we optimize slightly by sending NULL pointer: */
+
+    png_write_end(png_ptr, NULL);
+
+    return 0;
+}
+
+
+
+
+
+/* returns 0 if succeeds, 2 if libpng problem */
+
+int writepng_encode_row(mainprog_info *mainprog_ptr)  /* NON-interlaced only! */
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* image_data points at our one row of image data */
+
+    png_write_row(png_ptr, mainprog_ptr->image_data);
+
+    return 0;
+}
+
+
+
+
+
+/* returns 0 if succeeds, 2 if libpng problem */
+
+int writepng_encode_finish(mainprog_info *mainprog_ptr)   /* NON-interlaced! */
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* close out PNG file; if we had any text or time info to write after
+     * the IDATs, second argument would be info_ptr: */
+
+    png_write_end(png_ptr, NULL);
+
+    return 0;
+}
+
+
+
+
+
+void writepng_cleanup(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+    if (png_ptr && info_ptr)
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+}
+
+
+
+
+
+static void writepng_error_handler(png_structp png_ptr, png_const_charp msg)
+{
+    mainprog_info  *mainprog_ptr;
+
+    /* This function, aside from the extra step of retrieving the "error
+     * pointer" (below) and the fact that it exists within the application
+     * rather than within libpng, is essentially identical to libpng's
+     * default error handler.  The second point is critical:  since both
+     * setjmp() and longjmp() are called from the same code, they are
+     * guaranteed to have compatible notions of how big a jmp_buf is,
+     * regardless of whether _BSD_SOURCE or anything else has (or has not)
+     * been defined. */
+
+    fprintf(stderr, "writepng libpng error: %s\n", msg);
+    fflush(stderr);
+
+    mainprog_ptr = png_get_error_ptr(png_ptr);
+    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
+        fprintf(stderr,
+          "writepng severe error:  jmpbuf not recoverable; terminating.\n");
+        fflush(stderr);
+        exit(99);
+    }
+
+    /* Now we have our data structure we can use the information in it
+     * to return control to our own higher level code (all the points
+     * where 'setjmp' is called in this file.)  This will work with other
+     * error handling mechanisms as well - libpng always calls png_error
+     * when it can proceed no further, thus, so long as the error handler
+     * is intercepted, application code can do its own error recovery.
+     */
+    longjmp(mainprog_ptr->jmpbuf, 1);
+}
diff --git a/extern/libpng/contrib/gregbook/writepng.h b/extern/libpng/contrib/gregbook/writepng.h
new file mode 100644
index 0000000000..78b966b587
--- /dev/null
+++ b/extern/libpng/contrib/gregbook/writepng.h
@@ -0,0 +1,133 @@
+/*---------------------------------------------------------------------------
+
+   wpng - simple PNG-writing program                             writepng.h
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+
+#define TEXT_TITLE    0x01
+#define TEXT_AUTHOR   0x02
+#define TEXT_DESC     0x04
+#define TEXT_COPY     0x08
+#define TEXT_EMAIL    0x10
+#define TEXT_URL      0x20
+
+#define TEXT_TITLE_OFFSET        0
+#define TEXT_AUTHOR_OFFSET      72
+#define TEXT_COPY_OFFSET     (2*72)
+#define TEXT_EMAIL_OFFSET    (3*72)
+#define TEXT_URL_OFFSET      (4*72)
+#define TEXT_DESC_OFFSET     (5*72)
+
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+
+typedef struct _mainprog_info {
+    double gamma;
+    long width;
+    long height;
+    time_t modtime;
+    FILE *infile;
+    FILE *outfile;
+    void *png_ptr;
+    void *info_ptr;
+    uch *image_data;
+    uch **row_pointers;
+    char *title;
+    char *author;
+    char *desc;
+    char *copyright;
+    char *email;
+    char *url;
+    int filter;    /* command-line-filter flag, not PNG row filter! */
+    int pnmtype;
+    int sample_depth;
+    int interlaced;
+    int have_bg;
+    int have_time;
+    int have_text;
+    jmp_buf jmpbuf;
+    uch bg_red;
+    uch bg_green;
+    uch bg_blue;
+} mainprog_info;
+
+
+/* prototypes for public functions in writepng.c */
+
+void writepng_version_info(void);
+
+int writepng_init(mainprog_info *mainprog_ptr);
+
+int writepng_encode_image(mainprog_info *mainprog_ptr);
+
+int writepng_encode_row(mainprog_info *mainprog_ptr);
+
+int writepng_encode_finish(mainprog_info *mainprog_ptr);
+
+void writepng_cleanup(mainprog_info *mainprog_ptr);
diff --git a/extern/libpng/contrib/libtests/fakepng.c b/extern/libpng/contrib/libtests/fakepng.c
new file mode 100644
index 0000000000..6512c14010
--- /dev/null
+++ b/extern/libpng/contrib/libtests/fakepng.c
@@ -0,0 +1,65 @@
+/* Fake a PNG - just write it out directly.
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2014.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ */
+
+#include <stdio.h>
+#include <zlib.h> /* for crc32 */
+
+void
+put_uLong(uLong val)
+{
+   putchar(val >> 24);
+   putchar(val >> 16);
+   putchar(val >>  8);
+   putchar(val >>  0);
+}
+
+void
+put_chunk(const unsigned char *chunk, uInt length)
+{
+   uLong crc;
+
+   put_uLong(length-4); /* Exclude the tag */
+
+   fwrite(chunk, length, 1, stdout);
+
+   crc = crc32(0, Z_NULL, 0);
+   put_uLong(crc32(crc, chunk, length));
+}
+
+const unsigned char signature[] =
+{
+   137, 80, 78, 71, 13, 10, 26, 10
+};
+
+const unsigned char IHDR[] =
+{
+   73, 72, 68, 82, /* IHDR */
+   0, 0, 0, 1, /* width */
+   0, 0, 0, 1, /* height */
+   1, /* bit depth */
+   0, /* color type: greyscale */
+   0, /* compression method */
+   0, /* filter method */
+   0  /* interlace method: none */
+};
+
+const unsigned char unknown[] =
+{
+   'u', 'n', 'K', 'n' /* "unKn" - private safe to copy */
+};
+
+int
+main(void)
+{
+   fwrite(signature, sizeof signature, 1, stdout);
+   put_chunk(IHDR, sizeof IHDR);
+
+   for (;;)
+      put_chunk(unknown, sizeof unknown);
+}
diff --git a/extern/libpng/contrib/libtests/gentests.sh b/extern/libpng/contrib/libtests/gentests.sh
new file mode 100755
index 0000000000..f0f8d2395a
--- /dev/null
+++ b/extern/libpng/contrib/libtests/gentests.sh
@@ -0,0 +1,102 @@
+#!/bin/sh
+#
+# Copyright (c) 2013 John Cunningham Bowler
+#
+# Last changed in libpng 1.6.0 [February 14, 2013]
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Generate a set of PNG test images.  The images are generated in a
+# sub-directory called 'tests' by default, however a command line argument will
+# change that name.  The generation requires a built version of makepng in the
+# current directory.
+#
+usage(){
+   exec >&2
+   echo "$0 [<directory>]"
+   echo '  Generate a set of PNG test files in "directory" ("tests" by default)'
+   exit 1
+}
+
+mp="$PWD/makepng"
+test -x "$mp" || {
+   exec >&2
+   echo "$0: the 'makepng' program must exist"
+   echo "  in the directory within which this program:"
+   echo "    $mp"
+   echo "  is executed"
+   usage
+}
+
+# Just one argument: the directory
+testdir="tests"
+test $# -gt 1 && {
+   testdir="$1"
+   shift
+}
+test $# -eq 0 || usage
+
+# Take care not to clobber something
+if test -e "$testdir"
+then
+   test -d "$testdir" || usage
+else
+   # mkdir -p isn't portable, so do the following
+   mkdir "$testdir" 2>/dev/null || mkdir -p "$testdir" || usage
+fi
+
+# This fails in a very satisfactory way if it's not accessible
+cd "$testdir"
+:>"test$$.png" || {
+   exec >&2
+   echo "$testdir: directory not writable"
+   usage
+}
+rm "test$$.png" || {
+   exec >&2
+   echo "$testdir: you have create but not write privileges here."
+   echo "  This is unexpected.  You have a spurion; "'"'"test$$.png"'"'"."
+   echo "  You need to remove this yourself.  Try a different directory."
+   exit 1
+}
+
+# Now call makepng ($mp) to create every file we can think of with a
+# reasonable name
+doit(){
+   for gamma in "" --sRGB --linear --1.8
+   do
+      case "$gamma" in
+         "")
+            gname=;;
+         --sRGB)
+            gname="-srgb";;
+         --linear)
+            gname="-lin";;
+         --1.8)
+            gname="-18";;
+         *)
+            gname="-$gamma";;
+      esac
+      "$mp" $gamma "$1" "$2" "test-$1-$2$gname.png"
+   done
+}
+#
+for ct in gray palette
+do
+   for bd in 1 2 4 8
+   do
+      doit "$ct" "$bd"
+   done
+done
+#
+doit "gray" "16"
+#
+for ct in gray-alpha rgb rgb-alpha
+do
+   for bd in 8 16
+   do
+      doit "$ct" "$bd"
+   done
+done
diff --git a/extern/libpng/contrib/libtests/makepng.c b/extern/libpng/contrib/libtests/makepng.c
new file mode 100644
index 0000000000..312062bda7
--- /dev/null
+++ b/extern/libpng/contrib/libtests/makepng.c
@@ -0,0 +1,1941 @@
+/* makepng.c */
+#define _ISOC99_SOURCE
+/* Copyright: */
+#define COPYRIGHT "\251 2013,2015 John Cunningham Bowler"
+/*
+ * Last changed in libpng 1.6.20 [November 24, 2015]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Make a test PNG image.  The arguments are as follows:
+ *
+ *    makepng [--sRGB|--linear|--1.8] [--tRNS] [--nofilters] \
+ *       color-type bit-depth [file-name]
+ *
+ * The color-type may be numeric (and must match the numbers used by the PNG
+ * specification) or one of the format names listed below.  The bit-depth is the
+ * component bit depth, or the pixel bit-depth for a color-mapped image.
+ *
+ * Without any options no color-space information is written, with the options
+ * an sRGB or the appropriate gAMA chunk is written.  "1.8" refers to the
+ * display system used on older Apple computers to correct for high ambient
+ * light levels in the viewing environment; it applies a transform of
+ * approximately value^(1/1.45) to the color values and so a gAMA chunk of 65909
+ * is written (1.45/2.2).
+ *
+ * The image data is generated internally.  Unless --color is given the images
+ * used are as follows:
+ *
+ * 1 channel: a square image with a diamond, the least luminous colors are on
+ *    the edge of the image, the most luminous in the center.
+ *
+ * 2 channels: the color channel increases in luminosity from top to bottom, the
+ *    alpha channel increases in opacity from left to right.
+ *
+ * 3 channels: linear combinations of, from the top-left corner clockwise,
+ *    black, green, white, red.
+ *
+ * 4 channels: linear combinations of, from the top-left corner clockwise,
+ *    transparent, red, green, blue.
+ *
+ * For color-mapped images a four channel color-map is used and if --tRNS is
+ * given the PNG file has a tRNS chunk, as follows:
+ *
+ * 1-bit: entry 0 is transparent-red, entry 1 is opaque-white
+ * 2-bit: entry 0: transparent-green
+ *        entry 1: 40%-red
+ *        entry 2: 80%-blue
+ *        entry 3: opaque-white
+ * 4-bit: the 16 combinations of the 2-bit case
+ * 8-bit: the 256 combinations of the 4-bit case
+ *
+ * The palette always has 2^bit-depth entries and the tRNS chunk one fewer.  The
+ * image is the 1-channel diamond, but using palette index, not luminosity.
+ *
+ * For formats other than color-mapped ones if --tRNS is specified a tRNS chunk
+ * is generated with all channels equal to the low bits of 0x0101.
+ *
+ * Image size is determined by the final pixel depth in bits, i.e. channels x
+ * bit-depth, as follows:
+ *
+ * 8 bits or less:    64x64
+ * 16 bits:           256x256
+ * More than 16 bits: 1024x1024
+ *
+ * Row filtering is the libpng default but may be turned off (the 'none' filter
+ * is used on every row) with the --nofilters option.
+ *
+ * The images are not interlaced.
+ *
+ * If file-name is given then the PNG is written to that file, else it is
+ * written to stdout.  Notice that stdout is not supported on systems where, by
+ * default, it assumes text output; this program makes no attempt to change the
+ * text mode of stdout!
+ *
+ *    makepng --color=<color> ...
+ *
+ * If --color is given then the whole image has that color, color-mapped images
+ * will have exactly one palette entry and all image files with be 16x16 in
+ * size.  The color value is 1 to 4 decimal numbers as appropriate for the color
+ * type.
+ *
+ *    makepng --small ...
+ *
+ * If --small is given the images are no larger than required to include every
+ * possible pixel value for the format.
+ *
+ * For formats with pixels 8 bits or fewer in size the images consist of a
+ * single row with 2^pixel-depth pixels, one of every possible value.
+ *
+ * For formats with 16-bit pixels a 256x256 image is generated containing every
+ * possible pixel value.
+ *
+ * For larger pixel sizes a 256x256 image is generated where the first row
+ * consists of each pixel that has identical byte values throughout the pixel
+ * followed by rows where the byte values differ within the pixel.
+ *
+ * In all cases the pixel values are arranged in such a way that the SUB and UP
+ * filters give byte sequences for maximal zlib compression.  By default (if
+ * --nofilters is not given) the SUB filter is used on the first row and the UP
+ * filter on all following rows.
+ *
+ * The --small option is meant to provide good test-case coverage, however the
+ * images are not easy to examine visually.  Without the --small option the
+ * images contain identical color values; the pixel values are adjusted
+ * according to the gamma encoding with no gamma encoding being interpreted as
+ * sRGB.
+ *
+ * LICENSING
+ * =========
+ *
+ * This code is copyright of the authors, see the COPYRIGHT define above.  The
+ * code is licensed as above, using the libpng license.  The code generates
+ * images which are solely the product of the code; the options choose which of
+ * the many possibilities to generate.  The images that result (but not the code
+ * which generates them) are licensed as defined here:
+ *
+ * IMPORTANT: the COPYRIGHT #define must contain ISO-Latin-1 characters, the
+ * IMAGE_LICENSING #define must contain UTF-8 characters.  The 'copyright'
+ * symbol 0xA9U (\251) in ISO-Latin-1 encoding and 0xC20xA9 (\302\251) in UTF-8.
+ */
+#define IMAGE_LICENSING "Dedicated to the public domain per Creative Commons "\
+    "license \"CC0 1.0\"; https://creativecommons.org/publicdomain/zero/1.0/"
+
+#include <stddef.h> /* for offsetof */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <math.h>
+#include <errno.h>
+#include <assert.h>
+#include <stdint.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#include <zlib.h>
+
+/* Work round for GCC complaints about casting a (double) function result to
+ * an unsigned:
+ */
+static unsigned int
+flooru(double d)
+{
+   d = floor(d);
+   return (unsigned int)d;
+}
+
+static png_byte
+floorb(double d)
+{
+   d = floor(d);
+   return (png_byte)d;
+}
+
+/* This structure is used for inserting extra chunks (the --insert argument, not
+ * documented above.)
+ */
+typedef struct chunk_insert
+{
+   struct chunk_insert *next;
+   void               (*insert)(png_structp, png_infop, int, png_charpp);
+   int                  nparams;
+   png_charp            parameters[1];
+} chunk_insert;
+
+static unsigned int
+channels_of_type(int color_type)
+{
+   if (color_type & PNG_COLOR_MASK_PALETTE)
+      return 1;
+
+   else
+   {
+      int channels = 1;
+
+      if (color_type & PNG_COLOR_MASK_COLOR)
+         channels = 3;
+
+      if (color_type & PNG_COLOR_MASK_ALPHA)
+         return channels + 1;
+
+      else
+         return channels;
+   }
+}
+
+static unsigned int
+pixel_depth_of_type(int color_type, int bit_depth)
+{
+   return channels_of_type(color_type) * bit_depth;
+}
+
+static unsigned int
+image_size_of_type(int color_type, int bit_depth, unsigned int *colors,
+   int small)
+{
+   if (*colors)
+      return 16;
+
+   else
+   {
+      int pixel_depth = pixel_depth_of_type(color_type, bit_depth);
+
+      if (small)
+      {
+         if (pixel_depth <= 8) /* there will be one row */
+            return 1 << pixel_depth;
+
+         else
+            return 256;
+      }
+
+      else if (pixel_depth < 8)
+         return 64;
+
+      else if (pixel_depth > 16)
+         return 1024;
+
+      else
+         return 256;
+   }
+}
+
+static void
+set_color(png_colorp color, png_bytep trans, unsigned int red,
+   unsigned int green, unsigned int blue, unsigned int alpha,
+   png_const_bytep gamma_table)
+{
+   color->red = gamma_table[red];
+   color->green = gamma_table[green];
+   color->blue = gamma_table[blue];
+   *trans = (png_byte)alpha;
+}
+
+static int
+generate_palette(png_colorp palette, png_bytep trans, int bit_depth,
+   png_const_bytep gamma_table, unsigned int *colors)
+{
+   /*
+    * 1-bit: entry 0 is transparent-red, entry 1 is opaque-white
+    * 2-bit: entry 0: transparent-green
+    *        entry 1: 40%-red
+    *        entry 2: 80%-blue
+    *        entry 3: opaque-white
+    * 4-bit: the 16 combinations of the 2-bit case
+    * 8-bit: the 256 combinations of the 4-bit case
+    */
+   switch (colors[0])
+   {
+      default:
+         fprintf(stderr, "makepng: --colors=...: invalid count %u\n",
+            colors[0]);
+         exit(1);
+
+      case 1:
+         set_color(palette+0, trans+0, colors[1], colors[1], colors[1], 255,
+            gamma_table);
+         return 1;
+
+      case 2:
+         set_color(palette+0, trans+0, colors[1], colors[1], colors[1],
+            colors[2], gamma_table);
+         return 1;
+
+      case 3:
+         set_color(palette+0, trans+0, colors[1], colors[2], colors[3], 255,
+            gamma_table);
+         return 1;
+
+      case 4:
+         set_color(palette+0, trans+0, colors[1], colors[2], colors[3],
+            colors[4], gamma_table);
+         return 1;
+
+      case 0:
+         if (bit_depth == 1)
+         {
+            set_color(palette+0, trans+0, 255, 0, 0, 0, gamma_table);
+            set_color(palette+1, trans+1, 255, 255, 255, 255, gamma_table);
+            return 2;
+         }
+
+         else
+         {
+            unsigned int size = 1U << (bit_depth/2); /* 2, 4 or 16 */
+            unsigned int x, y;
+            volatile unsigned int ip = 0;
+
+            for (x=0; x<size; ++x) for (y=0; y<size; ++y)
+            {
+               ip = x + (size * y);
+
+               /* size is at most 16, so the scaled value below fits in 16 bits
+                */
+#              define interp(pos, c1, c2) ((pos * c1) + ((size-pos) * c2))
+#              define xyinterp(x, y, c1, c2, c3, c4) (((size * size / 2) +\
+                  (interp(x, c1, c2) * y + (size-y) * interp(x, c3, c4))) /\
+                  (size*size))
+
+               set_color(palette+ip, trans+ip,
+                  /* color:    green, red,blue,white */
+                  xyinterp(x, y,   0, 255,   0, 255),
+                  xyinterp(x, y, 255,   0,   0, 255),
+                  xyinterp(x, y,   0,   0, 255, 255),
+                  /* alpha:        0, 102, 204, 255) */
+                  xyinterp(x, y,   0, 102, 204, 255),
+                  gamma_table);
+            }
+
+            return ip+1;
+         }
+   }
+}
+
+static void
+set_value(png_bytep row, size_t rowbytes, png_uint_32 x, unsigned int bit_depth,
+   png_uint_32 value, png_const_bytep gamma_table, double conv)
+{
+   unsigned int mask = (1U << bit_depth)-1;
+
+   x *= bit_depth;  /* Maximum x is 4*1024, maximum bit_depth is 16 */
+
+   if (value <= mask)
+   {
+      png_uint_32 offset = x >> 3;
+
+      if (offset < rowbytes && (bit_depth < 16 || offset+1 < rowbytes))
+      {
+         row += offset;
+
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+               /* Don't gamma correct - values get smashed */
+               {
+                  unsigned int shift = (8 - bit_depth) - (x & 0x7U);
+
+                  mask <<= shift;
+                  value = (value << shift) & mask;
+                  *row = (png_byte)((*row & ~mask) | value);
+               }
+               return;
+
+            default:
+               fprintf(stderr, "makepng: bad bit depth (internal error)\n");
+               exit(1);
+
+            case 16:
+               value = flooru(65535*pow(value/65535.,conv)+.5);
+               *row++ = (png_byte)(value >> 8);
+               *row = (png_byte)value;
+               return;
+
+            case 8:
+               *row = gamma_table[value];
+               return;
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "makepng: row buffer overflow (internal error)\n");
+         exit(1);
+      }
+   }
+
+   else
+   {
+      fprintf(stderr, "makepng: component overflow (internal error)\n");
+      exit(1);
+   }
+}
+
+static int /* filter mask for row */
+generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
+   int bit_depth, png_const_bytep gamma_table, double conv,
+   unsigned int *colors, int small)
+{
+   int filters = 0; /* file *MASK*, 0 means the default, not NONE */
+   png_uint_32 size_max =
+      image_size_of_type(color_type, bit_depth, colors, small)-1;
+   png_uint_32 depth_max = (1U << bit_depth)-1; /* up to 65536 */
+
+   if (colors[0] == 0) if (small)
+   {
+      unsigned int pixel_depth = pixel_depth_of_type(color_type, bit_depth);
+
+      /* For pixel depths less than 16 generate a single row containing all the
+       * possible pixel values.  For 16 generate all 65536 byte pair
+       * combinations in a 256x256 pixel array.
+       */
+      switch (pixel_depth)
+      {
+         case 1:
+            assert(y == 0 && rowbytes == 1 && size_max == 1);
+            row[0] = 0x6CU; /* binary: 01101100, only top 2 bits used */
+            filters = PNG_FILTER_NONE;
+            break;
+
+         case 2:
+            assert(y == 0 && rowbytes == 1 && size_max == 3);
+            row[0] = 0x1BU; /* binary 00011011, all bits used */
+            filters = PNG_FILTER_NONE;
+            break;
+
+         case 4:
+            assert(y == 0 && rowbytes == 8 && size_max == 15);
+            row[0] = 0x01U;
+            row[1] = 0x23U; /* SUB gives 0x22U for all following bytes */
+            row[2] = 0x45U;
+            row[3] = 0x67U;
+            row[4] = 0x89U;
+            row[5] = 0xABU;
+            row[6] = 0xCDU;
+            row[7] = 0xEFU;
+            filters = PNG_FILTER_SUB;
+            break;
+
+         case 8:
+            /* The row will have all the pixel values in order starting with
+             * '1', the SUB filter will change every byte into '1' (including
+             * the last, which generates pixel value '0').  Since the SUB filter
+             * has value 1 this should result in maximum compression.
+             */
+            assert(y == 0 && rowbytes == 256 && size_max == 255);
+            for (;;)
+            {
+               row[size_max] = 0xFFU & (size_max+1);
+               if (size_max == 0)
+                  break;
+               --size_max;
+            }
+            filters = PNG_FILTER_SUB;
+            break;
+
+         case 16:
+            /* Rows are generated such that each row has a constant difference
+             * between the first and second byte of each pixel and so that the
+             * difference increases by 1 at each row.  The rows start with the
+             * first byte value of 0 and the value increases to 255 across the
+             * row.
+             *
+             * The difference starts at 1, so the first row is:
+             *
+             *     0 1 1 2 2 3 3 4 ... 254 255 255 0
+             *
+             * This means that running the SUB filter on the first row produces:
+             *
+             *   [SUB==1] 0 1 0 1 0 1...
+             *
+             * Then the difference is 2 on the next row, giving:
+             *
+             *    0 2 1 3 2 4 3 5 ... 254 0 255 1
+             *
+             * When the UP filter is run on this libpng produces:
+             *
+             *   [UP ==2] 0 1 0 1 0 1...
+             *
+             * And so on for all the remain rows to the final two * rows:
+             *
+             *    row 254: 0 255 1 0 2 1 3 2 4 3 ... 254 253 255 254
+             *    row 255: 0   0 1 1 2 2 3 3 4 4 ... 254 254 255 255
+             */
+            assert(rowbytes == 512 && size_max == 255);
+            for (;;)
+            {
+               row[2*size_max  ] = 0xFFU & size_max;
+               row[2*size_max+1] = 0xFFU & (size_max+y+1);
+               if (size_max == 0)
+                  break;
+               --size_max;
+            }
+            /* The first row must include PNG_FILTER_UP so that libpng knows we
+             * need to keep it for the following row:
+             */
+            filters = (y == 0 ? PNG_FILTER_SUB+PNG_FILTER_UP : PNG_FILTER_UP);
+            break;
+
+         case 24:
+         case 32:
+         case 48:
+         case 64:
+            /* The rows are filled by an alogorithm similar to the above, in the
+             * first row pixel bytes are all equal, increasing from 0 by 1 for
+             * each pixel.  In the second row the bytes within a pixel are
+             * incremented 1,3,5,7,... from the previous row byte.  Using an odd
+             * number ensures all the possible byte values are used.
+             */
+            assert(size_max == 255 && rowbytes == 256*(pixel_depth>>3));
+            pixel_depth >>= 3; /* now in bytes */
+            while (rowbytes > 0)
+            {
+               const size_t pixel_index = --rowbytes/pixel_depth;
+
+               if (y == 0)
+                  row[rowbytes] = 0xFFU & pixel_index;
+
+               else
+               {
+                  const size_t byte_offset =
+                     rowbytes - pixel_index * pixel_depth;
+
+                  row[rowbytes] =
+                     0xFFU & (pixel_index + (byte_offset * 2*y) + 1);
+               }
+            }
+            filters = (y == 0 ? PNG_FILTER_SUB+PNG_FILTER_UP : PNG_FILTER_UP);
+            break;
+
+         default:
+            assert(0/*NOT REACHED*/);
+      }
+   }
+
+   else switch (channels_of_type(color_type))
+   {
+   /* 1 channel: a square image with a diamond, the least luminous colors are on
+    *    the edge of the image, the most luminous in the center.
+    */
+      case 1:
+         {
+            png_uint_32 x;
+            png_uint_32 base = 2*size_max - abs(2*y-size_max);
+
+            for (x=0; x<=size_max; ++x)
+            {
+               png_uint_32 luma = base - abs(2*x-size_max);
+
+               /* 'luma' is now in the range 0..2*size_max, we need
+                * 0..depth_max
+                */
+               luma = (luma*depth_max + size_max) / (2*size_max);
+               set_value(row, rowbytes, x, bit_depth, luma, gamma_table, conv);
+            }
+         }
+         break;
+
+   /* 2 channels: the color channel increases in luminosity from top to bottom,
+    *    the alpha channel increases in opacity from left to right.
+    */
+      case 2:
+         {
+            png_uint_32 alpha = (depth_max * y * 2 + size_max) / (2 * size_max);
+            png_uint_32 x;
+
+            for (x=0; x<=size_max; ++x)
+            {
+               set_value(row, rowbytes, 2*x, bit_depth,
+                  (depth_max * x * 2 + size_max) / (2 * size_max), gamma_table,
+                  conv);
+               set_value(row, rowbytes, 2*x+1, bit_depth, alpha, gamma_table,
+                  conv);
+            }
+         }
+         break;
+
+   /* 3 channels: linear combinations of, from the top-left corner clockwise,
+    *    black, green, white, red.
+    */
+      case 3:
+         {
+            /* x0: the black->red scale (the value of the red component) at the
+             *     start of the row (blue and green are 0).
+             * x1: the green->white scale (the value of the red and blue
+             *     components at the end of the row; green is depth_max).
+             */
+            png_uint_32 Y = (depth_max * y * 2 + size_max) / (2 * size_max);
+            png_uint_32 x;
+
+            /* Interpolate x/depth_max from start to end:
+             *
+             *        start end         difference
+             * red:     Y    Y            0
+             * green:   0   depth_max   depth_max
+             * blue:    0    Y            Y
+             */
+            for (x=0; x<=size_max; ++x)
+            {
+               set_value(row, rowbytes, 3*x+0, bit_depth, /* red */ Y,
+                     gamma_table, conv);
+               set_value(row, rowbytes, 3*x+1, bit_depth, /* green */
+                  (depth_max * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+               set_value(row, rowbytes, 3*x+2, bit_depth, /* blue */
+                  (Y * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+            }
+         }
+         break;
+
+   /* 4 channels: linear combinations of, from the top-left corner clockwise,
+    *    transparent, red, green, blue.
+    */
+      case 4:
+         {
+            /* x0: the transparent->blue scale (the value of the blue and alpha
+             *     components) at the start of the row (red and green are 0).
+             * x1: the red->green scale (the value of the red and green
+             *     components at the end of the row; blue is 0 and alpha is
+             *     depth_max).
+             */
+            png_uint_32 Y = (depth_max * y * 2 + size_max) / (2 * size_max);
+            png_uint_32 x;
+
+            /* Interpolate x/depth_max from start to end:
+             *
+             *        start    end       difference
+             * red:     0   depth_max-Y depth_max-Y
+             * green:   0       Y             Y
+             * blue:    Y       0            -Y
+             * alpha:   Y    depth_max  depth_max-Y
+             */
+            for (x=0; x<=size_max; ++x)
+            {
+               set_value(row, rowbytes, 4*x+0, bit_depth, /* red */
+                  ((depth_max-Y) * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+               set_value(row, rowbytes, 4*x+1, bit_depth, /* green */
+                  (Y * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+               set_value(row, rowbytes, 4*x+2, bit_depth, /* blue */
+                  Y - (Y * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+               set_value(row, rowbytes, 4*x+3, bit_depth, /* alpha */
+                  Y + ((depth_max-Y) * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+            }
+         }
+         break;
+
+      default:
+         fprintf(stderr, "makepng: internal bad channel count\n");
+         exit(2);
+   }
+
+   else if (color_type & PNG_COLOR_MASK_PALETTE)
+   {
+      /* Palette with fixed color: the image rows are all 0 and the image width
+       * is 16.
+       */
+      memset(row, 0, rowbytes);
+   }
+
+   else if (colors[0] == channels_of_type(color_type))
+      switch (channels_of_type(color_type))
+      {
+         case 1:
+            {
+               png_uint_32 luma = colors[1];
+               png_uint_32 x;
+
+               for (x=0; x<=size_max; ++x)
+                  set_value(row, rowbytes, x, bit_depth, luma, gamma_table,
+                     conv);
+            }
+            break;
+
+         case 2:
+            {
+               png_uint_32 luma = colors[1];
+               png_uint_32 alpha = colors[2];
+               png_uint_32 x;
+
+               for (x=0; x<size_max; ++x)
+               {
+                  set_value(row, rowbytes, 2*x, bit_depth, luma, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 2*x+1, bit_depth, alpha, gamma_table,
+                     conv);
+               }
+            }
+            break;
+
+         case 3:
+            {
+               png_uint_32 red = colors[1];
+               png_uint_32 green = colors[2];
+               png_uint_32 blue = colors[3];
+               png_uint_32 x;
+
+               for (x=0; x<=size_max; ++x)
+               {
+                  set_value(row, rowbytes, 3*x+0, bit_depth, red, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 3*x+1, bit_depth, green, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 3*x+2, bit_depth, blue, gamma_table,
+                     conv);
+               }
+            }
+            break;
+
+         case 4:
+            {
+               png_uint_32 red = colors[1];
+               png_uint_32 green = colors[2];
+               png_uint_32 blue = colors[3];
+               png_uint_32 alpha = colors[4];
+               png_uint_32 x;
+
+               for (x=0; x<=size_max; ++x)
+               {
+                  set_value(row, rowbytes, 4*x+0, bit_depth, red, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 4*x+1, bit_depth, green, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 4*x+2, bit_depth, blue, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 4*x+3, bit_depth, alpha, gamma_table,
+                     conv);
+               }
+            }
+         break;
+
+         default:
+            fprintf(stderr, "makepng: internal bad channel count\n");
+            exit(2);
+      }
+
+   else
+   {
+      fprintf(stderr,
+         "makepng: --color: count(%u) does not match channels(%u)\n",
+         colors[0], channels_of_type(color_type));
+      exit(1);
+   }
+
+   return filters;
+}
+
+
+static void PNGCBAPI
+makepng_warning(png_structp png_ptr, png_const_charp message)
+{
+   const char **ep = png_get_error_ptr(png_ptr);
+   const char *name;
+
+   if (ep != NULL && *ep != NULL)
+      name = *ep;
+
+   else
+      name = "makepng";
+
+  fprintf(stderr, "%s: warning: %s\n", name, message);
+}
+
+static void PNGCBAPI
+makepng_error(png_structp png_ptr, png_const_charp message)
+{
+   makepng_warning(png_ptr, message);
+   png_longjmp(png_ptr, 1);
+}
+
+static int /* 0 on success, else an error code */
+write_png(const char **name, FILE *fp, int color_type, int bit_depth,
+   volatile png_fixed_point gamma, chunk_insert * volatile insert,
+   unsigned int filters, unsigned int *colors, int small, int tRNS)
+{
+   png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+      name, makepng_error, makepng_warning);
+   volatile png_infop info_ptr = NULL;
+   volatile png_bytep row = NULL;
+
+   if (png_ptr == NULL)
+   {
+      fprintf(stderr, "makepng: OOM allocating write structure\n");
+      return 1;
+   }
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_structp nv_ptr = png_ptr;
+      png_infop nv_info = info_ptr;
+
+      png_ptr = NULL;
+      info_ptr = NULL;
+      png_destroy_write_struct(&nv_ptr, &nv_info);
+      if (row != NULL) free(row);
+      return 1;
+   }
+
+   /* Allow benign errors so that we can write PNGs with errors */
+   png_set_benign_errors(png_ptr, 1/*allowed*/);
+
+   /* Max out the text compression level in an attempt to make the license
+    * small.   If --small then do the same for the IDAT.
+    */
+   if (small)
+      png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
+
+   png_set_text_compression_level(png_ptr, Z_BEST_COMPRESSION);
+
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   {
+      unsigned int size =
+         image_size_of_type(color_type, bit_depth, colors, small);
+      unsigned int ysize;
+      png_fixed_point real_gamma = 45455; /* For sRGB */
+      png_byte gamma_table[256];
+      double conv;
+
+      /* Normally images are square, but with 'small' we want to simply generate
+       * all the pixel values, or all that we reasonably can:
+       */
+      if (small)
+      {
+         unsigned int pixel_depth =
+            pixel_depth_of_type(color_type, bit_depth);
+
+         if (pixel_depth <= 8U)
+         {
+            assert(size == (1U<<pixel_depth));
+            ysize = 1U;
+         }
+
+         else
+         {
+            assert(size == 256U);
+            ysize = 256U;
+         }
+      }
+
+      else
+         ysize = size;
+
+      /* This function uses the libpng values used on read to carry extra
+       * information about the gamma:
+       */
+      if (gamma == PNG_GAMMA_MAC_18)
+         gamma = 65909;
+
+      else if (gamma > 0 && gamma < 1000)
+         gamma = PNG_FP_1;
+
+      if (gamma > 0)
+         real_gamma = gamma;
+
+      {
+         unsigned int i;
+
+         if (real_gamma == 45455) for (i=0; i<256; ++i)
+         {
+            gamma_table[i] = (png_byte)i;
+            conv = 1.;
+         }
+
+         else
+         {
+            /* Convert 'i' from sRGB (45455) to real_gamma, this makes
+             * the images look the same regardless of the gAMA chunk.
+             */
+            conv = real_gamma;
+            conv /= 45455;
+
+            gamma_table[0] = 0;
+
+            for (i=1; i<255; ++i)
+               gamma_table[i] = floorb(pow(i/255.,conv) * 255 + .5);
+
+            gamma_table[255] = 255;
+         }
+      }
+
+      png_set_IHDR(png_ptr, info_ptr, size, ysize, bit_depth, color_type,
+         PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+      if (color_type & PNG_COLOR_MASK_PALETTE)
+      {
+         int npalette;
+         png_color palette[256];
+         png_byte trans[256];
+
+         npalette = generate_palette(palette, trans, bit_depth, gamma_table,
+            colors);
+         png_set_PLTE(png_ptr, info_ptr, palette, npalette);
+
+         if (tRNS)
+            png_set_tRNS(png_ptr, info_ptr, trans, npalette-1,
+               NULL/*transparent color*/);
+
+         /* Reset gamma_table to prevent the image rows being changed */
+         for (npalette=0; npalette<256; ++npalette)
+            gamma_table[npalette] = (png_byte)npalette;
+      }
+
+      else if (tRNS)
+      {
+         png_color_16 col;
+
+         col.red = col.green = col.blue = col.gray =
+            0x0101U & ((1U<<bit_depth)-1U);
+         col.index = 0U;
+         png_set_tRNS(png_ptr, info_ptr, NULL/*trans*/, 1U, &col);
+      }
+
+      if (gamma == PNG_DEFAULT_sRGB)
+         png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_ABSOLUTE);
+
+      else if (gamma > 0) /* Else don't set color space information */
+      {
+         png_set_gAMA_fixed(png_ptr, info_ptr, real_gamma);
+
+         /* Just use the sRGB values here. */
+         png_set_cHRM_fixed(png_ptr, info_ptr,
+            /* color      x       y */
+            /* white */ 31270, 32900,
+            /* red   */ 64000, 33000,
+            /* green */ 30000, 60000,
+            /* blue  */ 15000,  6000
+         );
+      }
+
+      /* Insert extra information. */
+      while (insert != NULL)
+      {
+         insert->insert(png_ptr, info_ptr, insert->nparams, insert->parameters);
+         insert = insert->next;
+      }
+
+      /* Write the file header. */
+      png_write_info(png_ptr, info_ptr);
+
+      /* Restrict the filters */
+      png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, filters);
+
+      {
+#        ifdef PNG_WRITE_INTERLACING_SUPPORTED
+            int passes = png_set_interlace_handling(png_ptr);
+#        else /* !WRITE_INTERLACING */
+            int passes = 1;
+#        endif /* !WRITE_INTERLACING */
+         int pass;
+         size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+         row = malloc(rowbytes);
+
+         if (row == NULL)
+            png_error(png_ptr, "OOM allocating row buffer");
+
+         for (pass = 0; pass < passes; ++pass)
+         {
+            unsigned int y;
+
+            for (y=0; y<ysize; ++y)
+            {
+               unsigned int row_filters =
+                  generate_row(row, rowbytes, y, color_type, bit_depth,
+                        gamma_table, conv, colors, small);
+
+               if (row_filters != 0 && filters == PNG_ALL_FILTERS)
+                  png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, row_filters);
+
+               png_write_row(png_ptr, row);
+            }
+         }
+      }
+   }
+
+   /* Finish writing the file. */
+   png_write_end(png_ptr, info_ptr);
+
+   {
+      png_structp nv_ptr = png_ptr;
+      png_infop nv_info = info_ptr;
+
+      png_ptr = NULL;
+      info_ptr = NULL;
+      png_destroy_write_struct(&nv_ptr, &nv_info);
+   }
+   free(row);
+   return 0;
+}
+
+
+static size_t
+load_file(png_const_charp name, png_bytepp result)
+{
+   FILE *fp = tmpfile();
+
+   if (fp != NULL)
+   {
+      FILE *ip = fopen(name, "rb");
+
+      if (ip != NULL)
+      {
+         size_t total = 0;
+         int ch;
+
+         for (;;)
+         {
+            ch = getc(ip);
+            if (ch == EOF) break;
+            putc(ch, fp);
+            ++total;
+         }
+
+         if (ferror(ip))
+         {
+            perror(name);
+            fprintf(stderr, "%s: read error\n", name);
+            (void)fclose(ip);
+         }
+
+         else
+         {
+            (void)fclose(ip);
+
+            if (ferror(fp))
+            {
+               perror("temporary file");
+               fprintf(stderr, "temporary file write error\n");
+            }
+
+            else
+            {
+               rewind(fp);
+
+               if (total > 0)
+               {
+                  /* Round up to a multiple of 4 here to allow an iCCP profile
+                   * to be padded to a 4x boundary.
+                   */
+                  png_bytep data = malloc((total+3)&~3);
+
+                  if (data != NULL)
+                  {
+                     size_t new_size = 0;
+
+                     for (;;)
+                     {
+                        ch = getc(fp);
+                        if (ch == EOF) break;
+                        data[new_size++] = (png_byte)ch;
+                     }
+
+                     if (ferror(fp) || new_size != total)
+                     {
+                        perror("temporary file");
+                        fprintf(stderr, "temporary file read error\n");
+                        free(data);
+                     }
+
+                     else
+                     {
+                        (void)fclose(fp);
+                        *result = data;
+                        return total;
+                     }
+                  }
+
+                  else
+                     fprintf(stderr, "%s: out of memory loading file\n", name);
+               }
+
+               else
+                  fprintf(stderr, "%s: empty file\n", name);
+            }
+         }
+      }
+
+      else
+      {
+         perror(name);
+         fprintf(stderr, "%s: open failed\n", name);
+      }
+
+      fclose(fp);
+   }
+
+   else
+      fprintf(stderr, "makepng: %s: could not open temporary file\n", name);
+
+   exit(1);
+   return 0;
+}
+
+static size_t
+load_fake(png_charp param, png_bytepp profile)
+{
+   char *endptr = NULL;
+   uint64_t size = strtoull(param, &endptr, 0/*base*/);
+
+   /* The 'fake' format is <number>*[string] */
+   if (endptr != NULL && *endptr == '*')
+   {
+      size_t len = strlen(++endptr);
+      size_t result = (size_t)size;
+
+      if (len == 0) len = 1; /* capture the terminating '\0' */
+
+      /* Now repeat that string to fill 'size' bytes. */
+      if (result == size && (*profile = malloc(result)) != NULL)
+      {
+         png_bytep out = *profile;
+
+         if (len == 1)
+            memset(out, *endptr, result);
+
+         else
+         {
+            while (size >= len)
+            {
+               memcpy(out, endptr, len);
+               out += len;
+               size -= len;
+            }
+            memcpy(out, endptr, size);
+         }
+
+         return result;
+      }
+
+      else
+      {
+         fprintf(stderr, "%s: size exceeds system limits\n", param);
+         exit(1);
+      }
+   }
+
+   return 0;
+}
+
+static void
+check_param_count(int nparams, int expect)
+{
+   if (nparams != expect)
+   {
+      fprintf(stderr, "bad parameter count (internal error)\n");
+      exit(1);
+   }
+}
+
+static void
+insert_iCCP(png_structp png_ptr, png_infop info_ptr, int nparams,
+   png_charpp params)
+{
+   png_bytep profile = NULL;
+   png_uint_32 proflen = 0;
+   int result;
+
+   check_param_count(nparams, 2);
+
+   switch (params[1][0])
+   {
+      case '<':
+         {
+            size_t filelen = load_file(params[1]+1, &profile);
+            if (filelen > 0xfffffffc) /* Maximum profile length */
+            {
+               fprintf(stderr, "%s: file too long (%lu) for an ICC profile\n",
+                  params[1]+1, (unsigned long)filelen);
+               exit(1);
+            }
+
+            proflen = (png_uint_32)filelen;
+         }
+         break;
+
+      case '0': case '1': case '2': case '3': case '4':
+      case '5': case '6': case '7': case '8': case '9':
+         {
+            size_t fake_len = load_fake(params[1], &profile);
+
+            if (fake_len > 0) /* else a simple parameter */
+            {
+               if (fake_len > 0xffffffff) /* Maximum profile length */
+               {
+                  fprintf(stderr,
+                     "%s: fake data too long (%lu) for an ICC profile\n",
+                     params[1], (unsigned long)fake_len);
+                  exit(1);
+               }
+               proflen = (png_uint_32)(fake_len & ~3U);
+               /* Always fix up the profile length. */
+               png_save_uint_32(profile, proflen);
+               break;
+            }
+         }
+
+      default:
+         fprintf(stderr, "--insert iCCP \"%s\": unrecognized\n", params[1]);
+         fprintf(stderr, "  use '<' to read a file: \"<filename\"\n");
+         exit(1);
+   }
+
+   result = 1;
+
+   if (proflen & 3)
+   {
+      fprintf(stderr,
+         "makepng: --insert iCCP %s: profile length made a multiple of 4\n",
+         params[1]);
+
+      /* load_file allocates extra space for this padding, the ICC spec requires
+       * padding with zero bytes.
+       */
+      while (proflen & 3)
+         profile[proflen++] = 0;
+   }
+
+   if (profile != NULL && proflen > 3)
+   {
+      png_uint_32 prof_header = png_get_uint_32(profile);
+
+      if (prof_header != proflen)
+      {
+         fprintf(stderr, "--insert iCCP %s: profile length field wrong:\n",
+            params[1]);
+         fprintf(stderr, "  actual %lu, recorded value %lu (corrected)\n",
+            (unsigned long)proflen, (unsigned long)prof_header);
+         png_save_uint_32(profile, proflen);
+      }
+   }
+
+   if (result && profile != NULL && proflen >=4)
+      png_set_iCCP(png_ptr, info_ptr, params[0], PNG_COMPRESSION_TYPE_BASE,
+         profile, proflen);
+
+   if (profile)
+      free(profile);
+
+   if (!result)
+      exit(1);
+}
+
+static void
+clear_text(png_text *text, png_charp keyword)
+{
+   text->compression = -1; /* none */
+   text->key = keyword;
+   text->text = NULL;
+   text->text_length = 0; /* libpng calculates this */
+   text->itxt_length = 0; /* libpng calculates this */
+   text->lang = NULL;
+   text->lang_key = NULL;
+}
+
+static void
+set_text(png_structp png_ptr, png_infop info_ptr, png_textp text,
+   png_charp param)
+{
+   switch (param[0])
+   {
+      case '<':
+         {
+            png_bytep file = NULL;
+
+            text->text_length = load_file(param+1, &file);
+            text->text = (png_charp)file;
+         }
+         break;
+
+      case '0': case '1': case '2': case '3': case '4':
+      case '5': case '6': case '7': case '8': case '9':
+         {
+            png_bytep data = NULL;
+            size_t fake_len = load_fake(param, &data);
+
+            if (fake_len > 0) /* else a simple parameter */
+            {
+               text->text_length = fake_len;
+               text->text = (png_charp)data;
+               break;
+            }
+         }
+
+      default:
+         text->text = param;
+         break;
+   }
+
+   png_set_text(png_ptr, info_ptr, text, 1);
+
+   if (text->text != param)
+      free(text->text);
+}
+
+static void
+insert_tEXt(png_structp png_ptr, png_infop info_ptr, int nparams,
+   png_charpp params)
+{
+   png_text text;
+
+   check_param_count(nparams, 2);
+   clear_text(&text, params[0]);
+   set_text(png_ptr, info_ptr, &text, params[1]);
+}
+
+static void
+insert_zTXt(png_structp png_ptr, png_infop info_ptr, int nparams,
+   png_charpp params)
+{
+   png_text text;
+
+   check_param_count(nparams, 2);
+   clear_text(&text, params[0]);
+   text.compression = 0; /* deflate */
+   set_text(png_ptr, info_ptr, &text, params[1]);
+}
+
+static void
+insert_iTXt(png_structp png_ptr, png_infop info_ptr, int nparams,
+   png_charpp params)
+{
+   png_text text;
+
+   check_param_count(nparams, 4);
+   clear_text(&text, params[0]);
+   text.compression = 2; /* iTXt + deflate */
+   text.lang = params[1];/* language tag */
+   text.lang_key = params[2]; /* translated keyword */
+   set_text(png_ptr, info_ptr, &text, params[3]);
+}
+
+static void
+insert_hIST(png_structp png_ptr, png_infop info_ptr, int nparams,
+      png_charpp params)
+{
+   int i;
+   png_uint_16 freq[256];
+
+   /* libpng takes the count from the PLTE count; we don't check it here but we
+    * do set the array to 0 for unspecified entries.
+    */
+   memset(freq, 0, sizeof freq);
+   for (i=0; i<nparams; ++i)
+   {
+      char *endptr = NULL;
+      unsigned long int l = strtoul(params[i], &endptr, 0/*base*/);
+
+      if (params[i][0] && *endptr == 0 && l <= 65535)
+         freq[i] = (png_uint_16)l;
+
+      else
+      {
+         fprintf(stderr, "hIST[%d]: %s: invalid frequency\n", i, params[i]);
+         exit(1);
+      }
+   }
+
+   png_set_hIST(png_ptr, info_ptr, freq);
+}
+
+static png_byte
+bval(png_const_structrp png_ptr, png_charp param, unsigned int maxval)
+{
+   char *endptr = NULL;
+   unsigned long int l = strtoul(param, &endptr, 0/*base*/);
+
+   if (param[0] && *endptr == 0 && l <= maxval)
+      return (png_byte)l;
+
+   else
+      png_error(png_ptr, "sBIT: invalid sBIT value");
+}
+
+static void
+insert_sBIT(png_structp png_ptr, png_infop info_ptr, int nparams,
+      png_charpp params)
+{
+   int ct = png_get_color_type(png_ptr, info_ptr);
+   int c = (ct & PNG_COLOR_MASK_COLOR ? 3 : 1) +
+      (ct & PNG_COLOR_MASK_ALPHA ? 1 : 0);
+   unsigned int maxval =
+      ct & PNG_COLOR_MASK_PALETTE ? 8U : png_get_bit_depth(png_ptr, info_ptr);
+   png_color_8 sBIT;
+
+   if (nparams != c)
+      png_error(png_ptr, "sBIT: incorrect parameter count");
+
+   if (ct & PNG_COLOR_MASK_COLOR)
+   {
+      sBIT.red = bval(png_ptr, params[0], maxval);
+      sBIT.green = bval(png_ptr, params[1], maxval);
+      sBIT.blue = bval(png_ptr, params[2], maxval);
+      sBIT.gray = 42;
+   }
+
+   else
+   {
+      sBIT.red = sBIT.green = sBIT.blue = 42;
+      sBIT.gray = bval(png_ptr, params[0], maxval);
+   }
+
+   if (ct & PNG_COLOR_MASK_ALPHA)
+      sBIT.alpha = bval(png_ptr, params[nparams-1], maxval);
+
+   else
+      sBIT.alpha = 42;
+
+   png_set_sBIT(png_ptr, info_ptr, &sBIT);
+}
+
+#if 0
+static void
+insert_sPLT(png_structp png_ptr, png_infop info_ptr, int nparams, png_charpp params)
+{
+   fprintf(stderr, "insert sPLT: NYI\n");
+}
+#endif
+
+static int
+find_parameters(png_const_charp what, png_charp param, png_charp *list,
+   int nparams)
+{
+   /* Parameters are separated by '\n' or ':' characters, up to nparams are
+    * accepted (more is an error) and the number found is returned.
+    */
+   int i;
+   for (i=0; *param && i<nparams; ++i)
+   {
+      list[i] = param;
+      while (*++param) if (*param == '\n' || *param == ':')
+      {
+         *param++ = 0; /* Terminate last parameter */
+         break;        /* And start a new one. */
+      }
+   }
+
+   if (*param)
+   {
+      fprintf(stderr, "--insert %s: too many parameters (%s)\n", what, param);
+      exit(1);
+   }
+
+   list[i] = NULL; /* terminates list */
+   return i; /* number of parameters filled in */
+}
+
+static void
+bad_parameter_count(png_const_charp what, int nparams)
+{
+   fprintf(stderr, "--insert %s: bad parameter count %d\n", what, nparams);
+   exit(1);
+}
+
+static chunk_insert *
+make_insert(png_const_charp what,
+   void (*insert)(png_structp, png_infop, int, png_charpp),
+   int nparams, png_charpp list)
+{
+   int i;
+   chunk_insert *cip;
+
+   cip = malloc(offsetof(chunk_insert,parameters) +
+      nparams * sizeof (png_charp));
+
+   if (cip == NULL)
+   {
+      fprintf(stderr, "--insert %s: out of memory allocating %d parameters\n",
+         what, nparams);
+      exit(1);
+   }
+
+   cip->next = NULL;
+   cip->insert = insert;
+   cip->nparams = nparams;
+   for (i=0; i<nparams; ++i)
+      cip->parameters[i] = list[i];
+
+   return cip;
+}
+
+static chunk_insert *
+find_insert(png_const_charp what, png_charp param)
+{
+   png_uint_32 chunk = 0;
+   png_charp parameter_list[1024];
+   int i, nparams;
+
+   /* Assemble the chunk name */
+   for (i=0; i<4; ++i)
+   {
+      char ch = what[i];
+
+      if ((ch >= 65 && ch <= 90) || (ch >= 97 && ch <= 122))
+         chunk = (chunk << 8) + what[i];
+
+      else
+         break;
+   }
+
+   if (i < 4 || what[4] != 0)
+   {
+      fprintf(stderr, "makepng --insert \"%s\": invalid chunk name\n", what);
+      exit(1);
+   }
+
+   /* Assemble the parameter list. */
+   nparams = find_parameters(what, param, parameter_list, 1024);
+
+#  define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
+
+   switch (chunk)
+   {
+      case CHUNK(105,67,67,80):  /* iCCP */
+         if (nparams == 2)
+            return make_insert(what, insert_iCCP, nparams, parameter_list);
+         break;
+
+      case CHUNK(116,69,88,116): /* tEXt */
+         if (nparams == 2)
+            return make_insert(what, insert_tEXt, nparams, parameter_list);
+         break;
+
+      case CHUNK(122,84,88,116): /* zTXt */
+         if (nparams == 2)
+            return make_insert(what, insert_zTXt, nparams, parameter_list);
+         break;
+
+      case CHUNK(105,84,88,116): /* iTXt */
+         if (nparams == 4)
+            return make_insert(what, insert_iTXt, nparams, parameter_list);
+         break;
+
+      case CHUNK(104,73,83,84):  /* hIST */
+         if (nparams <= 256)
+            return make_insert(what, insert_hIST, nparams, parameter_list);
+         break;
+
+      case CHUNK(115,66,73,84): /* sBIT */
+         if (nparams <= 4)
+            return make_insert(what, insert_sBIT, nparams, parameter_list);
+         break;
+
+#if 0
+      case CHUNK(115,80,76,84):  /* sPLT */
+         return make_insert(what, insert_sPLT, nparams, parameter_list);
+#endif
+
+      default:
+         fprintf(stderr, "makepng --insert \"%s\": unrecognized chunk name\n",
+            what);
+         exit(1);
+   }
+
+   bad_parameter_count(what, nparams);
+   return NULL;
+}
+
+/* This is necessary because libpng expects writeable strings for things like
+ * text chunks (maybe this should be fixed...)
+ */
+static png_charp
+strstash(png_const_charp foo)
+{
+   /* The program indicates a memory allocation error by crashing, this is by
+    * design.
+    */
+   if (foo != NULL)
+   {
+      png_charp bar = malloc(strlen(foo)+1);
+      return strcpy(bar, foo);
+   }
+
+   return NULL;
+}
+
+static png_charp
+strstash_list(const png_const_charp *text)
+{
+   size_t foo = 0;
+   png_charp result, bar;
+   const png_const_charp *line = text;
+
+   while (*line != NULL)
+      foo += strlen(*line++);
+
+   result = bar = malloc(foo+1);
+
+   line = text;
+   while (*line != NULL)
+   {
+      foo = strlen(*line);
+      memcpy(bar, *line++, foo);
+      bar += foo;
+   }
+
+   *bar = 0;
+   return result;
+}
+
+/* These are used to insert Copyright and Licence fields, they allow the text to
+ * have \n unlike the --insert option.
+ */
+static chunk_insert *
+add_tEXt(const char *key, const png_const_charp *text)
+{
+   static char what[5] = { 116, 69, 88, 116, 0 };
+   png_charp parameter_list[3];
+
+   parameter_list[0] = strstash(key);
+   parameter_list[1] = strstash_list(text);
+   parameter_list[2] = NULL;
+
+   return make_insert(what, insert_tEXt, 2, parameter_list);
+}
+
+static chunk_insert *
+add_iTXt(const char *key, const char *language, const char *language_key,
+      const png_const_charp *text)
+{
+   static char what[5] = { 105, 84, 88, 116, 0 };
+   png_charp parameter_list[5];
+
+   parameter_list[0] = strstash(key);
+   parameter_list[1] = strstash(language);
+   parameter_list[2] = strstash(language_key);
+   parameter_list[3] = strstash_list(text);
+   parameter_list[4] = NULL;
+
+   return make_insert(what, insert_iTXt, 4, parameter_list);
+}
+
+/* This is a not-very-good parser for a sequence of numbers (including 0).  It
+ * doesn't accept some apparently valid things, but it accepts all the sensible
+ * combinations.
+ */
+static void
+parse_color(char *arg, unsigned int *colors)
+{
+   unsigned int ncolors = 0;
+
+   while (*arg && ncolors < 4)
+   {
+      char *ep = arg;
+
+      unsigned long ul = strtoul(arg, &ep, 0);
+
+      if (ul > 65535)
+      {
+         fprintf(stderr, "makepng --color=...'%s': too big\n", arg);
+         exit(1);
+      }
+
+      if (ep == arg)
+      {
+         fprintf(stderr, "makepng --color=...'%s': not a valid color\n", arg);
+         exit(1);
+      }
+
+      if (*ep) ++ep; /* skip a separator */
+      arg = ep;
+
+      colors[++ncolors] = (unsigned int)ul; /* checked above */
+   }
+
+   if (*arg)
+   {
+      fprintf(stderr, "makepng --color=...'%s': too many values\n", arg);
+      exit(1);
+   }
+
+   *colors = ncolors;
+}
+
+int
+main(int argc, char **argv)
+{
+   FILE *fp = stdout;
+   const char *file_name = NULL;
+   int color_type = 8; /* invalid */
+   int bit_depth = 32; /* invalid */
+   int small = 0; /* make full size images */
+   int tRNS = 0; /* don't output a tRNS chunk */
+   unsigned int colors[5];
+   unsigned int filters = PNG_ALL_FILTERS;
+   png_fixed_point gamma = 0; /* not set */
+   chunk_insert *head_insert = NULL;
+   chunk_insert **insert_ptr = &head_insert;
+
+   memset(colors, 0, sizeof colors);
+
+   while (--argc > 0)
+   {
+      char *arg = *++argv;
+
+      if (strcmp(arg, "--small") == 0)
+      {
+         small = 1;
+         continue;
+      }
+
+      if (strcmp(arg, "--tRNS") == 0)
+      {
+         tRNS = 1;
+         continue;
+      }
+
+      if (strcmp(arg, "--sRGB") == 0)
+      {
+         gamma = PNG_DEFAULT_sRGB;
+         continue;
+      }
+
+      if (strcmp(arg, "--linear") == 0)
+      {
+         gamma = PNG_FP_1;
+         continue;
+      }
+
+      if (strcmp(arg, "--1.8") == 0)
+      {
+         gamma = PNG_GAMMA_MAC_18;
+         continue;
+      }
+
+      if (strcmp(arg, "--nofilters") == 0)
+      {
+         filters = PNG_FILTER_NONE;
+         continue;
+      }
+
+      if (strncmp(arg, "--color=", 8) == 0)
+      {
+          parse_color(arg+8, colors);
+          continue;
+      }
+
+      if (argc >= 3 && strcmp(arg, "--insert") == 0)
+      {
+         png_const_charp what = *++argv;
+         png_charp param = *++argv;
+         chunk_insert *new_insert;
+
+         argc -= 2;
+
+         new_insert = find_insert(what, param);
+
+         if (new_insert != NULL)
+         {
+            *insert_ptr = new_insert;
+            insert_ptr = &new_insert->next;
+         }
+
+         continue;
+      }
+
+      if (arg[0] == '-')
+      {
+         fprintf(stderr, "makepng: %s: invalid option\n", arg);
+         exit(1);
+      }
+
+      if (strcmp(arg, "palette") == 0)
+      {
+         color_type = PNG_COLOR_TYPE_PALETTE;
+         continue;
+      }
+
+      if (strncmp(arg, "gray", 4) == 0)
+      {
+         if (arg[4] == 0)
+         {
+            color_type = PNG_COLOR_TYPE_GRAY;
+            continue;
+         }
+
+         else if (strcmp(arg+4, "a") == 0 ||
+            strcmp(arg+4, "alpha") == 0 ||
+            strcmp(arg+4, "-alpha") == 0)
+         {
+            color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+            continue;
+         }
+      }
+
+      if (strncmp(arg, "rgb", 3) == 0)
+      {
+         if (arg[3] == 0)
+         {
+            color_type = PNG_COLOR_TYPE_RGB;
+            continue;
+         }
+
+         else if (strcmp(arg+3, "a") == 0 ||
+            strcmp(arg+3, "alpha") == 0 ||
+            strcmp(arg+3, "-alpha") == 0)
+         {
+            color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+            continue;
+         }
+      }
+
+      if (color_type == 8 && isdigit(arg[0]))
+      {
+         color_type = atoi(arg);
+         if (color_type < 0 || color_type > 6 || color_type == 1 ||
+            color_type == 5)
+         {
+            fprintf(stderr, "makepng: %s: not a valid color type\n", arg);
+            exit(1);
+         }
+
+         continue;
+      }
+
+      if (bit_depth == 32 && isdigit(arg[0]))
+      {
+         bit_depth = atoi(arg);
+         if (bit_depth <= 0 || bit_depth > 16 ||
+            (bit_depth & -bit_depth) != bit_depth)
+         {
+            fprintf(stderr, "makepng: %s: not a valid bit depth\n", arg);
+            exit(1);
+         }
+
+         continue;
+      }
+
+      if (argc == 1) /* It's the file name */
+      {
+         fp = fopen(arg, "wb");
+         if (fp == NULL)
+         {
+            fprintf(stderr, "%s: %s: could not open\n", arg, strerror(errno));
+            exit(1);
+         }
+
+         file_name = arg;
+         continue;
+      }
+
+      fprintf(stderr, "makepng: %s: unknown argument\n", arg);
+      exit(1);
+   } /* argument while loop */
+
+   if (color_type == 8 || bit_depth == 32)
+   {
+      fprintf(stderr, "usage: makepng [--small] [--sRGB|--linear|--1.8] "
+         "[--color=...] color-type bit-depth [file-name]\n"
+         "  Make a test PNG file, by default writes to stdout.\n"
+         "  Other options are available, UTSL.\n");
+      exit(1);
+   }
+
+   /* Check the colors */
+   {
+      unsigned int lim = (color_type == PNG_COLOR_TYPE_PALETTE ? 255U :
+         (1U<<bit_depth)-1);
+      unsigned int i;
+
+      for (i=1; i<=colors[0]; ++i)
+         if (colors[i] > lim)
+         {
+            fprintf(stderr, "makepng: --color=...: %u out of range [0..%u]\n",
+               colors[i], lim);
+            exit(1);
+         }
+   }
+
+   /* small and colors are incomparible (will probably crash if both are used at
+    * the same time!)
+    */
+   if (small && colors[0] != 0)
+   {
+      fprintf(stderr, "makepng: --color --small: only one at a time!\n");
+      exit(1);
+   }
+
+   /* Restrict the filters for more speed to those we know are used for the
+    * generated images.
+    */
+   if (filters == PNG_ALL_FILTERS && !small/*small provides defaults*/)
+   {
+      if ((color_type & PNG_COLOR_MASK_PALETTE) != 0 || bit_depth < 8)
+         filters = PNG_FILTER_NONE;
+
+      else if (color_type & PNG_COLOR_MASK_COLOR) /* rgb */
+      {
+         if (bit_depth == 8)
+            filters &= ~(PNG_FILTER_NONE | PNG_FILTER_AVG);
+
+         else
+            filters = PNG_FILTER_SUB | PNG_FILTER_PAETH;
+      }
+
+      else /* gray 8 or 16-bit */
+         filters &= ~PNG_FILTER_NONE;
+   }
+
+   /* Insert standard copyright and licence text. */
+   {
+      static png_const_charp copyright[] =
+      {
+         COPYRIGHT, /* ISO-Latin-1 */
+         NULL
+      };
+      static png_const_charp licensing[] =
+      {
+         IMAGE_LICENSING, /* UTF-8 */
+         NULL
+      };
+
+      chunk_insert *new_insert;
+
+      new_insert = add_tEXt("Copyright", copyright);
+      if (new_insert != NULL)
+      {
+         *insert_ptr = new_insert;
+         insert_ptr = &new_insert->next;
+      }
+
+      new_insert = add_iTXt("Licensing", "en", NULL, licensing);
+      if (new_insert != NULL)
+      {
+         *insert_ptr = new_insert;
+         insert_ptr = &new_insert->next;
+      }
+   }
+
+   {
+      int ret = write_png(&file_name, fp, color_type, bit_depth, gamma,
+         head_insert, filters, colors, small, tRNS);
+
+      if (ret != 0 && file_name != NULL)
+         remove(file_name);
+
+      return ret;
+   }
+}
diff --git a/extern/libpng/contrib/libtests/pngimage.c b/extern/libpng/contrib/libtests/pngimage.c
new file mode 100644
index 0000000000..f130c043df
--- /dev/null
+++ b/extern/libpng/contrib/libtests/pngimage.c
@@ -0,0 +1,1712 @@
+/* pngimage.c
+ *
+ * Copyright (c) 2015,2016 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.24 [August 4, 2016]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Test the png_read_png and png_write_png interfaces.  Given a PNG file load it
+ * using png_read_png and then write with png_write_png.  Test all possible
+ * transforms.
+ */
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdio.h>
+#include <assert.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#ifndef PNG_SETJMP_SUPPORTED
+#  include <setjmp.h> /* because png.h did *not* include this */
+#endif
+
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+   /* READ_PNG and WRITE_PNG were not defined, so: */
+#  ifdef PNG_INFO_IMAGE_SUPPORTED
+#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#        define PNG_READ_PNG_SUPPORTED
+#     endif /* SEQUENTIAL_READ */
+#     ifdef PNG_WRITE_SUPPORTED
+#        define PNG_WRITE_PNG_SUPPORTED
+#     endif /* WRITE */
+#  endif /* INFO_IMAGE */
+#endif /* pre 1.7.0 */
+
+#ifdef PNG_READ_PNG_SUPPORTED
+/* If a transform is valid on both read and write this implies that if the
+ * transform is applied to read it must also be applied on write to produce
+ * meaningful data.  This is because these transforms when performed on read
+ * produce data with a memory format that does not correspond to a PNG format.
+ *
+ * Most of these transforms are invertible; after applying the transform on
+ * write the result is the original PNG data that would have would have been
+ * read if no transform were applied.
+ *
+ * The exception is _SHIFT, which destroys the low order bits marked as not
+ * significant in a PNG with the sBIT chunk.
+ *
+ * The following table lists, for each transform, the conditions under which it
+ * is expected to do anything.  Conditions are defined as follows:
+ *
+ * 1) Color mask bits required - simply a mask to AND with color_type; one of
+ *    these must be present for the transform to fire, except that 0 means
+ *    'always'.
+ * 2) Color mask bits which must be absent - another mask - none of these must
+ *    be present.
+ * 3) Bit depths - a mask of component bit depths for the transform to fire.
+ * 4) 'read' - the transform works in png_read_png.
+ * 5) 'write' - the transform works in png_write_png.
+ * 6) PNG_INFO_chunk; a mask of the chunks that must be present for the
+ *    transform to fire.  All must be present - the requirement is that
+ *    png_get_valid() & mask == mask, so if mask is 0 there is no requirement.
+ *
+ * The condition refers to the original image state - if multiple transforms are
+ * used together it is possible to cause a transform that wouldn't fire on the
+ * original image to fire.
+ */
+static struct transform_info
+{
+   const char *name;
+   int         transform;
+   png_uint_32 valid_chunks;
+#     define CHUNK_NONE 0
+#     define CHUNK_sBIT PNG_INFO_sBIT
+#     define CHUNK_tRNS PNG_INFO_tRNS
+   png_byte    color_mask_required;
+   png_byte    color_mask_absent;
+#     define COLOR_MASK_X   0
+#     define COLOR_MASK_P   PNG_COLOR_MASK_PALETTE
+#     define COLOR_MASK_C   PNG_COLOR_MASK_COLOR
+#     define COLOR_MASK_A   PNG_COLOR_MASK_ALPHA
+#     define COLOR_MASK_ALL (PALETTE+COLOR+ALPHA)  /* absent = gray, no alpha */
+   png_byte    bit_depths;
+#     define BD_ALL  (1 + 2 + 4 + 8 + 16)
+#     define BD_PAL  (1 + 2 + 4 + 8)
+#     define BD_LOW  (1 + 2 + 4)
+#     define BD_16   16
+#     define BD_TRUE (8+16) /* i.e. true-color depths */
+   png_byte    when;
+#     define TRANSFORM_R  1
+#     define TRANSFORM_W  2
+#     define TRANSFORM_RW 3
+   png_byte    tested; /* the transform was tested somewhere */
+} transform_info[] =
+{
+   /* List ALL the PNG_TRANSFORM_ macros here.  Check for support using the READ
+    * macros; even if the transform is supported on write it cannot be tested
+    * without the read support.
+    */
+#  define T(name,chunk,cm_required,cm_absent,bd,when)\
+   {  #name, PNG_TRANSFORM_ ## name, CHUNK_ ## chunk,\
+      COLOR_MASK_ ## cm_required, COLOR_MASK_ ## cm_absent, BD_ ## bd,\
+      TRANSFORM_ ## when, 0/*!tested*/ }
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+   T(STRIP_16,            NONE, X,   X,   16,  R),
+      /* drops the bottom 8 bits when bit depth is 16 */
+#endif
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   T(STRIP_ALPHA,         NONE, A,   X,  ALL,  R),
+      /* removes the alpha channel if present */
+#endif
+#ifdef PNG_WRITE_PACK_SUPPORTED
+#  define TRANSFORM_RW_PACK TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_PACK TRANSFORM_R
+#endif
+#ifdef PNG_READ_PACK_SUPPORTED
+   T(PACKING,             NONE, X,   X,  LOW, RW_PACK),
+      /* unpacks low-bit-depth components into 1 byte per component on read,
+       * reverses this on write.
+       */
+#endif
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+#  define TRANSFORM_RW_PACKSWAP TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_PACKSWAP TRANSFORM_R
+#endif
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+   T(PACKSWAP,            NONE, X,   X,  LOW, RW_PACKSWAP),
+      /* reverses the order of low-bit-depth components packed into a byte */
+#endif
+#ifdef PNG_READ_EXPAND_SUPPORTED
+   T(EXPAND,              NONE, P,   X,  ALL,  R),
+      /* expands PLTE PNG files to RGB (no tRNS) or RGBA (tRNS) *
+       * Note that the 'EXPAND' transform does lots of different things: */
+   T(EXPAND,              NONE, X,   C,  ALL,  R),
+      /* expands grayscale PNG files to RGB, or RGBA */
+   T(EXPAND,              tRNS, X,   A,  ALL,  R),
+      /* expands the tRNS chunk in files without alpha */
+#endif
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+#  define TRANSFORM_RW_INVERT TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_INVERT TRANSFORM_R
+#endif
+#ifdef PNG_READ_INVERT_SUPPORTED
+   T(INVERT_MONO,         NONE, X,   C,  ALL, RW_INVERT),
+      /* converts gray-scale components to 1..0 from 0..1 */
+#endif
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+#  define TRANSFORM_RW_SHIFT TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_SHIFT TRANSFORM_R
+#endif
+#ifdef PNG_READ_SHIFT_SUPPORTED
+   T(SHIFT,               sBIT, X,   X,  ALL, RW_SHIFT),
+      /* reduces component values to the original range based on the sBIT chunk,
+       * this is only partially reversible - the low bits are lost and cannot be
+       * recovered on write.  In fact write code replicates the bits to generate
+       * new low-order bits.
+       */
+#endif
+#ifdef PNG_WRITE_BGR_SUPPORTED
+#  define TRANSFORM_RW_BGR TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_BGR TRANSFORM_R
+#endif
+#ifdef PNG_READ_BGR_SUPPORTED
+   T(BGR,                 NONE, C,   P, TRUE, RW_BGR),
+      /* reverses the rgb component values of true-color pixels */
+#endif
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+#  define TRANSFORM_RW_SWAP_ALPHA TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_SWAP_ALPHA TRANSFORM_R
+#endif
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+   T(SWAP_ALPHA,          NONE, A,   X, TRUE, RW_SWAP_ALPHA),
+      /* swaps the alpha channel of RGBA or GA pixels to the front - ARGB or
+       * AG, on write reverses the process.
+       */
+#endif
+#ifdef PNG_WRITE_SWAP_SUPPORTED
+#  define TRANSFORM_RW_SWAP TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_SWAP TRANSFORM_R
+#endif
+#ifdef PNG_READ_SWAP_SUPPORTED
+   T(SWAP_ENDIAN,         NONE, X,   P,   16, RW_SWAP),
+      /* byte-swaps 16-bit component values */
+#endif
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+#  define TRANSFORM_RW_INVERT_ALPHA TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_INVERT_ALPHA TRANSFORM_R
+#endif
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+   T(INVERT_ALPHA,        NONE, A,   X, TRUE, RW_INVERT_ALPHA),
+      /* converts an alpha channel from 0..1 to 1..0 */
+#endif
+#ifdef PNG_WRITE_FILLER_SUPPORTED
+   T(STRIP_FILLER_BEFORE, NONE, A,   P, TRUE,  W), /* 'A' for a filler! */
+      /* on write skips a leading filler channel; testing requires data with a
+       * filler channel so this is produced from RGBA or GA images by removing
+       * the 'alpha' flag from the color type in place.
+       */
+   T(STRIP_FILLER_AFTER,  NONE, A,   P, TRUE,  W),
+      /* on write strips a trailing filler channel */
+#endif
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   T(GRAY_TO_RGB,         NONE, X,   C,  ALL,  R),
+      /* expands grayscale images to RGB, also causes the palette part of
+       * 'EXPAND' to happen.  Low bit depth grayscale images are expanded to
+       * 8-bits per component and no attempt is made to convert the image to a
+       * palette image.  While this transform is partially reversible
+       * png_write_png does not currently support this.
+       */
+   T(GRAY_TO_RGB,         NONE, P,   X,  ALL,  R),
+      /* The 'palette' side effect mentioned above; a bit bogus but this is the
+       * way the libpng code works.
+       */
+#endif
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   T(EXPAND_16,           NONE, X,   X,  PAL,  R),
+      /* expands images to 16-bits per component, as a side effect expands
+       * palette images to RGB and expands the tRNS chunk if present, so it can
+       * modify 16-bit per component images as well:
+       */
+   T(EXPAND_16,           tRNS, X,   A,   16,  R),
+      /* side effect of EXPAND_16 - expands the tRNS chunk in an RGB or G 16-bit
+       * image.
+       */
+#endif
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+   T(SCALE_16,            NONE, X,   X,   16,  R),
+      /* scales 16-bit components to 8-bits. */
+#endif
+
+   { NULL /*name*/, 0, 0, 0, 0, 0, 0, 0/*!tested*/ }
+
+#undef T
+};
+
+#define ARRAY_SIZE(a) ((sizeof a)/(sizeof a[0]))
+#define TTABLE_SIZE ARRAY_SIZE(transform_info)
+
+/* Some combinations of options that should be reversible are not; these cases
+ * are bugs.
+ */
+static int known_bad_combos[][2] =
+{
+   /* problem, antidote */
+   { PNG_TRANSFORM_SHIFT | PNG_TRANSFORM_INVERT_ALPHA, 0/*antidote*/ }
+};
+
+static int
+is_combo(int transforms)
+{
+   return transforms & (transforms-1); /* non-zero if more than one set bit */
+}
+
+static int
+first_transform(int transforms)
+{
+   return transforms & -transforms; /* lowest set bit */
+}
+
+static int
+is_bad_combo(int transforms)
+{
+   unsigned int i;
+
+   for (i=0; i<ARRAY_SIZE(known_bad_combos); ++i)
+   {
+      int combo = known_bad_combos[i][0];
+
+      if ((combo & transforms) == combo &&
+         (transforms & known_bad_combos[i][1]) == 0)
+         return 1;
+   }
+
+   return 0; /* combo is ok */
+}
+
+static const char *
+transform_name(int t)
+   /* The name, if 't' has multiple bits set the name of the lowest set bit is
+    * returned.
+    */
+{
+   unsigned int i;
+
+   t &= -t; /* first set bit */
+
+   for (i=0; i<TTABLE_SIZE; ++i) if (transform_info[i].name != NULL)
+   {
+      if ((transform_info[i].transform & t) != 0)
+         return transform_info[i].name;
+   }
+
+   return "invalid transform";
+}
+
+/* Variables calculated by validate_T below and used to record all the supported
+ * transforms.  Need (unsigned int) here because of the places where these
+ * values are used (unsigned compares in the 'exhaustive' iterator.)
+ */
+static unsigned int read_transforms, write_transforms, rw_transforms;
+
+static void
+validate_T(void)
+   /* Validate the above table - this just builds the above values */
+{
+   unsigned int i;
+
+   for (i=0; i<TTABLE_SIZE; ++i) if (transform_info[i].name != NULL)
+   {
+      if (transform_info[i].when & TRANSFORM_R)
+         read_transforms |= transform_info[i].transform;
+
+      if (transform_info[i].when & TRANSFORM_W)
+         write_transforms |= transform_info[i].transform;
+   }
+
+   /* Reversible transforms are those which are supported on both read and
+    * write.
+    */
+   rw_transforms = read_transforms & write_transforms;
+}
+
+/* FILE DATA HANDLING
+ *    The original file is cached in memory.  During write the output file is
+ *    written to memory.
+ *
+ *    In both cases the file data is held in a linked list of buffers - not all
+ *    of these are in use at any time.
+ */
+#define NEW(type) ((type *)malloc(sizeof (type)))
+#define DELETE(ptr) (free(ptr))
+
+struct buffer_list
+{
+   struct buffer_list *next;         /* next buffer in list */
+   png_byte            buffer[1024]; /* the actual buffer */
+};
+
+struct buffer
+{
+   struct buffer_list  *last;       /* last buffer in use */
+   size_t               end_count;  /* bytes in the last buffer */
+   struct buffer_list  *current;    /* current buffer being read */
+   size_t               read_count; /* count of bytes read from current */
+   struct buffer_list   first;      /* the very first buffer */
+};
+
+static void
+buffer_init(struct buffer *buffer)
+   /* Call this only once for a given buffer */
+{
+   buffer->first.next = NULL;
+   buffer->last = NULL;
+   buffer->current = NULL;
+}
+
+static void
+buffer_destroy_list(struct buffer_list *list)
+{
+   if (list != NULL)
+   {
+      struct buffer_list *next = list->next;
+      DELETE(list);
+      buffer_destroy_list(next);
+   }
+}
+
+static void
+buffer_destroy(struct buffer *buffer)
+{
+   struct buffer_list *list = buffer->first.next;
+   buffer_init(buffer);
+   buffer_destroy_list(list);
+}
+
+#ifdef PNG_WRITE_PNG_SUPPORTED
+static void
+buffer_start_write(struct buffer *buffer)
+{
+   buffer->last = &buffer->first;
+   buffer->end_count = 0;
+   buffer->current = NULL;
+}
+#endif
+
+static void
+buffer_start_read(struct buffer *buffer)
+{
+   buffer->current = &buffer->first;
+   buffer->read_count = 0;
+}
+
+#ifdef ENOMEM /* required by POSIX 1003.1 */
+#  define MEMORY ENOMEM
+#else
+#  define MEMORY ERANGE /* required by ANSI-C */
+#endif
+static struct buffer *
+get_buffer(png_structp pp)
+   /* Used from libpng callbacks to get the current buffer */
+{
+   return (struct buffer*)png_get_io_ptr(pp);
+}
+
+static struct buffer_list *
+buffer_extend(struct buffer_list *current)
+{
+   struct buffer_list *add;
+
+   assert(current->next == NULL);
+
+   add = NEW(struct buffer_list);
+   if (add == NULL)
+      return NULL;
+
+   add->next = NULL;
+   current->next = add;
+
+   return add;
+}
+
+/* Load a buffer from a file; does the equivalent of buffer_start_write.  On a
+ * read error returns an errno value, else returns 0.
+ */
+static int
+buffer_from_file(struct buffer *buffer, FILE *fp)
+{
+   struct buffer_list *last = &buffer->first;
+   size_t count = 0;
+
+   for (;;)
+   {
+      size_t r = fread(last->buffer+count, 1/*size*/,
+         (sizeof last->buffer)-count, fp);
+
+      if (r > 0)
+      {
+         count += r;
+
+         if (count >= sizeof last->buffer)
+         {
+            assert(count == sizeof last->buffer);
+            count = 0;
+
+            if (last->next == NULL)
+            {
+               last = buffer_extend(last);
+               if (last == NULL)
+                  return MEMORY;
+            }
+
+            else
+               last = last->next;
+         }
+      }
+
+      else /* fread failed - probably end of file */
+      {
+         if (feof(fp))
+         {
+            buffer->last = last;
+            buffer->end_count = count;
+            return 0; /* no error */
+         }
+
+         /* Some kind of funky error; errno should be non-zero */
+         return errno == 0 ? ERANGE : errno;
+      }
+   }
+}
+
+/* This structure is used to control the test of a single file. */
+typedef enum
+{
+   VERBOSE,        /* switches on all messages */
+   INFORMATION,
+   WARNINGS,       /* switches on warnings */
+   LIBPNG_WARNING,
+   APP_WARNING,
+   ERRORS,         /* just errors */
+   APP_FAIL,       /* continuable error - no need to longjmp */
+   LIBPNG_ERROR,   /* this and higher cause a longjmp */
+   LIBPNG_BUG,     /* erroneous behavior in libpng */
+   APP_ERROR,      /* such as out-of-memory in a callback */
+   QUIET,          /* no normal messages */
+   USER_ERROR,     /* such as file-not-found */
+   INTERNAL_ERROR
+} error_level;
+#define LEVEL_MASK      0xf   /* where the level is in 'options' */
+
+#define EXHAUSTIVE      0x010 /* Test all combinations of active options */
+#define STRICT          0x020 /* Fail on warnings as well as errors */
+#define LOG             0x040 /* Log pass/fail to stdout */
+#define CONTINUE        0x080 /* Continue on APP_FAIL errors */
+#define SKIP_BUGS       0x100 /* Skip over known bugs */
+#define LOG_SKIPPED     0x200 /* Log skipped bugs */
+#define FIND_BAD_COMBOS 0x400 /* Attempt to deduce bad combos */
+#define LIST_COMBOS     0x800 /* List combos by name */
+
+/* Result masks apply to the result bits in the 'results' field below; these
+ * bits are simple 1U<<error_level.  A pass requires either nothing worse than
+ * warnings (--relaxes) or nothing worse than information (--strict)
+ */
+#define RESULT_STRICT(r)   (((r) & ~((1U<<WARNINGS)-1)) == 0)
+#define RESULT_RELAXED(r)  (((r) & ~((1U<<ERRORS)-1)) == 0)
+
+struct display
+{
+   jmp_buf        error_return;      /* Where to go to on error */
+
+   const char    *filename;          /* The name of the original file */
+   const char    *operation;         /* Operation being performed */
+   int            transforms;        /* Transform used in operation */
+   png_uint_32    options;           /* See display_log below */
+   png_uint_32    results;           /* A mask of errors seen */
+
+
+   png_structp    original_pp;       /* used on the original read */
+   png_infop      original_ip;       /* set by the original read */
+
+   size_t         original_rowbytes; /* of the original rows: */
+   png_bytepp     original_rows;     /* from the original read */
+
+   /* Original chunks valid */
+   png_uint_32    chunks;
+
+   /* Original IHDR information */
+   png_uint_32    width;
+   png_uint_32    height;
+   int            bit_depth;
+   int            color_type;
+   int            interlace_method;
+   int            compression_method;
+   int            filter_method;
+
+   /* Derived information for the original image. */
+   int            active_transforms;  /* transforms that do something on read */
+   int            ignored_transforms; /* transforms that should do nothing */
+
+   /* Used on a read, both the original read and when validating a written
+    * image.
+    */
+   png_structp    read_pp;
+   png_infop      read_ip;
+
+#  ifdef PNG_WRITE_PNG_SUPPORTED
+      /* Used to write a new image (the original info_ptr is used) */
+      png_structp   write_pp;
+      struct buffer written_file;   /* where the file gets written */
+#  endif
+
+   struct buffer  original_file;     /* Data read from the original file */
+};
+
+static void
+display_init(struct display *dp)
+   /* Call this only once right at the start to initialize the control
+    * structure, the (struct buffer) lists are maintained across calls - the
+    * memory is not freed.
+    */
+{
+   memset(dp, 0, sizeof *dp);
+   dp->options = WARNINGS; /* default to !verbose, !quiet */
+   dp->filename = NULL;
+   dp->operation = NULL;
+   dp->original_pp = NULL;
+   dp->original_ip = NULL;
+   dp->original_rows = NULL;
+   dp->read_pp = NULL;
+   dp->read_ip = NULL;
+   buffer_init(&dp->original_file);
+
+#  ifdef PNG_WRITE_PNG_SUPPORTED
+      dp->write_pp = NULL;
+      buffer_init(&dp->written_file);
+#  endif
+}
+
+static void
+display_clean_read(struct display *dp)
+{
+   if (dp->read_pp != NULL)
+      png_destroy_read_struct(&dp->read_pp, &dp->read_ip, NULL);
+}
+
+#ifdef PNG_WRITE_PNG_SUPPORTED
+static void
+display_clean_write(struct display *dp)
+{
+      if (dp->write_pp != NULL)
+         png_destroy_write_struct(&dp->write_pp, NULL);
+}
+#endif
+
+static void
+display_clean(struct display *dp)
+{
+#  ifdef PNG_WRITE_PNG_SUPPORTED
+      display_clean_write(dp);
+#  endif
+   display_clean_read(dp);
+
+   dp->original_rowbytes = 0;
+   dp->original_rows = NULL;
+   dp->chunks = 0;
+
+   png_destroy_read_struct(&dp->original_pp, &dp->original_ip, NULL);
+   /* leave the filename for error detection */
+   dp->results = 0; /* reset for next time */
+}
+
+static void
+display_destroy(struct display *dp)
+{
+    /* Release any memory held in the display. */
+#  ifdef PNG_WRITE_PNG_SUPPORTED
+      buffer_destroy(&dp->written_file);
+#  endif
+
+   buffer_destroy(&dp->original_file);
+}
+
+static struct display *
+get_dp(png_structp pp)
+   /* The display pointer is always stored in the png_struct error pointer */
+{
+   struct display *dp = (struct display*)png_get_error_ptr(pp);
+
+   if (dp == NULL)
+   {
+      fprintf(stderr, "pngimage: internal error (no display)\n");
+      exit(99); /* prevents a crash */
+   }
+
+   return dp;
+}
+
+/* error handling */
+#ifdef __GNUC__
+#  define VGATTR __attribute__((__format__ (__printf__,3,4)))
+   /* Required to quiet GNUC warnings when the compiler sees a stdarg function
+    * that calls one of the stdio v APIs.
+    */
+#else
+#  define VGATTR
+#endif
+static void VGATTR
+display_log(struct display *dp, error_level level, const char *fmt, ...)
+   /* 'level' is as above, fmt is a stdio style format string.  This routine
+    * does not return if level is above LIBPNG_WARNING
+    */
+{
+   dp->results |= 1U << level;
+
+   if (level > (error_level)(dp->options & LEVEL_MASK))
+   {
+      const char *lp;
+      va_list ap;
+
+      switch (level)
+      {
+         case INFORMATION:    lp = "information"; break;
+         case LIBPNG_WARNING: lp = "warning(libpng)"; break;
+         case APP_WARNING:    lp = "warning(pngimage)"; break;
+         case APP_FAIL:       lp = "error(continuable)"; break;
+         case LIBPNG_ERROR:   lp = "error(libpng)"; break;
+         case LIBPNG_BUG:     lp = "bug(libpng)"; break;
+         case APP_ERROR:      lp = "error(pngimage)"; break;
+         case USER_ERROR:     lp = "error(user)"; break;
+
+         case INTERNAL_ERROR: /* anything unexpected is an internal error: */
+         case VERBOSE: case WARNINGS: case ERRORS: case QUIET:
+         default:             lp = "bug(pngimage)"; break;
+      }
+
+      fprintf(stderr, "%s: %s: %s",
+         dp->filename != NULL ? dp->filename : "<stdin>", lp, dp->operation);
+
+      if (dp->transforms != 0)
+      {
+         int tr = dp->transforms;
+
+         if (is_combo(tr))
+         {
+            if (dp->options & LIST_COMBOS)
+            {
+               int trx = tr;
+
+               fprintf(stderr, "(");
+               if (trx)
+               {
+                  int start = 0;
+
+                  while (trx)
+                  {
+                     int trz = trx & -trx;
+
+                     if (start) fprintf(stderr, "+");
+                     fprintf(stderr, "%s", transform_name(trz));
+                     start = 1;
+                     trx &= ~trz;
+                  }
+               }
+
+               else
+                  fprintf(stderr, "-");
+               fprintf(stderr, ")");
+            }
+
+            else
+               fprintf(stderr, "(0x%x)", tr);
+         }
+
+         else
+            fprintf(stderr, "(%s)", transform_name(tr));
+      }
+
+      fprintf(stderr, ": ");
+
+      va_start(ap, fmt);
+      vfprintf(stderr, fmt, ap);
+      va_end(ap);
+
+      fputc('\n', stderr);
+   }
+   /* else do not output any message */
+
+   /* Errors cause this routine to exit to the fail code */
+   if (level > APP_FAIL || (level > ERRORS && !(dp->options & CONTINUE)))
+      longjmp(dp->error_return, level);
+}
+
+/* error handler callbacks for libpng */
+static void PNGCBAPI
+display_warning(png_structp pp, png_const_charp warning)
+{
+   display_log(get_dp(pp), LIBPNG_WARNING, "%s", warning);
+}
+
+static void PNGCBAPI
+display_error(png_structp pp, png_const_charp error)
+{
+   struct display *dp = get_dp(pp);
+
+   display_log(dp, LIBPNG_ERROR, "%s", error);
+}
+
+static void
+display_cache_file(struct display *dp, const char *filename)
+   /* Does the initial cache of the file. */
+{
+   FILE *fp;
+   int ret;
+
+   dp->filename = filename;
+
+   if (filename != NULL)
+   {
+      fp = fopen(filename, "rb");
+      if (fp == NULL)
+         display_log(dp, USER_ERROR, "open failed: %s", strerror(errno));
+   }
+
+   else
+      fp = stdin;
+
+   ret = buffer_from_file(&dp->original_file, fp);
+
+   fclose(fp);
+
+   if (ret != 0)
+      display_log(dp, APP_ERROR, "read failed: %s", strerror(ret));
+}
+
+static void
+buffer_read(struct display *dp, struct buffer *bp, png_bytep data,
+   size_t size)
+{
+   struct buffer_list *last = bp->current;
+   size_t read_count = bp->read_count;
+
+   while (size > 0)
+   {
+      size_t avail;
+
+      if (last == NULL ||
+         (last == bp->last && read_count >= bp->end_count))
+      {
+         display_log(dp, USER_ERROR, "file truncated (%lu bytes)",
+            (unsigned long)size);
+         /*NOTREACHED*/
+         break;
+      }
+
+      else if (read_count >= sizeof last->buffer)
+      {
+         /* Move to the next buffer: */
+         last = last->next;
+         read_count = 0;
+         bp->current = last; /* Avoid update outside the loop */
+
+         /* And do a sanity check (the EOF case is caught above) */
+         if (last == NULL)
+         {
+            display_log(dp, INTERNAL_ERROR, "damaged buffer list");
+            /*NOTREACHED*/
+            break;
+         }
+      }
+
+      avail = (sizeof last->buffer) - read_count;
+      if (avail > size)
+         avail = size;
+
+      memcpy(data, last->buffer + read_count, avail);
+      read_count += avail;
+      size -= avail;
+      data += avail;
+   }
+
+   bp->read_count = read_count;
+}
+
+static void PNGCBAPI
+read_function(png_structp pp, png_bytep data, size_t size)
+{
+   buffer_read(get_dp(pp), get_buffer(pp), data, size);
+}
+
+static void
+read_png(struct display *dp, struct buffer *bp, const char *operation,
+   int transforms)
+{
+   png_structp pp;
+   png_infop   ip;
+
+   /* This cleans out any previous read and sets operation and transforms to
+    * empty.
+    */
+   display_clean_read(dp);
+
+   if (operation != NULL) /* else this is a verify and do not overwrite info */
+   {
+      dp->operation = operation;
+      dp->transforms = transforms;
+   }
+
+   dp->read_pp = pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, dp,
+      display_error, display_warning);
+   if (pp == NULL)
+      display_log(dp, LIBPNG_ERROR, "failed to create read struct");
+
+   /* The png_read_png API requires us to make the info struct, but it does the
+    * call to png_read_info.
+    */
+   dp->read_ip = ip = png_create_info_struct(pp);
+   if (ip == NULL)
+      display_log(dp, LIBPNG_ERROR, "failed to create info struct");
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      /* Remove the user limits, if any */
+      png_set_user_limits(pp, 0x7fffffff, 0x7fffffff);
+#  endif
+
+   /* Set the IO handling */
+   buffer_start_read(bp);
+   png_set_read_fn(pp, bp, read_function);
+
+   png_read_png(pp, ip, transforms, NULL/*params*/);
+
+#if 0 /* crazy debugging */
+   {
+      png_bytep pr = png_get_rows(pp, ip)[0];
+      size_t rb = png_get_rowbytes(pp, ip);
+      size_t cb;
+      char c = ' ';
+
+      fprintf(stderr, "%.4x %2d (%3lu bytes):", transforms, png_get_bit_depth(pp,ip), (unsigned long)rb);
+
+      for (cb=0; cb<rb; ++cb)
+         fputc(c, stderr), fprintf(stderr, "%.2x", pr[cb]), c='.';
+
+      fputc('\n', stderr);
+   }
+#endif
+}
+
+static void
+update_display(struct display *dp)
+   /* called once after the first read to update all the info, original_pp and
+    * original_ip must have been filled in.
+    */
+{
+   png_structp pp;
+   png_infop   ip;
+
+   /* Now perform the initial read with a 0 transform. */
+   read_png(dp, &dp->original_file, "original read", 0/*no transform*/);
+
+   /* Move the result to the 'original' fields */
+   dp->original_pp = pp = dp->read_pp, dp->read_pp = NULL;
+   dp->original_ip = ip = dp->read_ip, dp->read_ip = NULL;
+
+   dp->original_rowbytes = png_get_rowbytes(pp, ip);
+   if (dp->original_rowbytes == 0)
+      display_log(dp, LIBPNG_BUG, "png_get_rowbytes returned 0");
+
+   dp->chunks = png_get_valid(pp, ip, 0xffffffff);
+   if ((dp->chunks & PNG_INFO_IDAT) == 0) /* set by png_read_png */
+      display_log(dp, LIBPNG_BUG, "png_read_png did not set IDAT flag");
+
+   dp->original_rows = png_get_rows(pp, ip);
+   if (dp->original_rows == NULL)
+      display_log(dp, LIBPNG_BUG, "png_read_png did not create row buffers");
+
+   if (!png_get_IHDR(pp, ip,
+      &dp->width, &dp->height, &dp->bit_depth, &dp->color_type,
+      &dp->interlace_method, &dp->compression_method, &dp->filter_method))
+      display_log(dp, LIBPNG_BUG, "png_get_IHDR failed");
+
+   /* 'active' transforms are discovered based on the original image format;
+    * running one active transform can activate others.  At present the code
+    * does not attempt to determine the closure.
+    */
+   {
+      png_uint_32 chunks = dp->chunks;
+      int active = 0, inactive = 0;
+      int ct = dp->color_type;
+      int bd = dp->bit_depth;
+      unsigned int i;
+
+      for (i=0; i<TTABLE_SIZE; ++i) if (transform_info[i].name != NULL)
+      {
+         int transform = transform_info[i].transform;
+
+         if ((transform_info[i].valid_chunks == 0 ||
+               (transform_info[i].valid_chunks & chunks) != 0) &&
+            (transform_info[i].color_mask_required & ct) ==
+               transform_info[i].color_mask_required &&
+            (transform_info[i].color_mask_absent & ct) == 0 &&
+            (transform_info[i].bit_depths & bd) != 0 &&
+            (transform_info[i].when & TRANSFORM_R) != 0)
+            active |= transform;
+
+         else if ((transform_info[i].when & TRANSFORM_R) != 0)
+            inactive |= transform;
+      }
+
+      /* Some transforms appear multiple times in the table; the 'active' status
+       * is the logical OR of these and the inactive status must be adjusted to
+       * take this into account.
+       */
+      inactive &= ~active;
+
+      dp->active_transforms = active;
+      dp->ignored_transforms = inactive; /* excluding write-only transforms */
+   }
+}
+
+static int
+compare_read(struct display *dp, int applied_transforms)
+{
+   /* Compare the png_info from read_ip with original_info */
+   size_t rowbytes;
+   png_uint_32 width, height;
+   int bit_depth, color_type;
+   int interlace_method, compression_method, filter_method;
+   const char *e = NULL;
+
+   png_get_IHDR(dp->read_pp, dp->read_ip, &width, &height, &bit_depth,
+      &color_type, &interlace_method, &compression_method, &filter_method);
+
+#  define C(item) if (item != dp->item) \
+      display_log(dp, APP_WARNING, "IHDR " #item "(%lu) changed to %lu",\
+         (unsigned long)dp->item, (unsigned long)item), e = #item
+
+   /* The IHDR should be identical: */
+   C(width);
+   C(height);
+   C(bit_depth);
+   C(color_type);
+   C(interlace_method);
+   C(compression_method);
+   C(filter_method);
+
+   /* 'e' remains set to the name of the last thing changed: */
+   if (e)
+      display_log(dp, APP_ERROR, "IHDR changed (%s)", e);
+
+   /* All the chunks from the original PNG should be preserved in the output PNG
+    * because the PNG format has not been changed.
+    */
+   {
+      unsigned long chunks =
+         png_get_valid(dp->read_pp, dp->read_ip, 0xffffffff);
+
+      if (chunks != dp->chunks)
+         display_log(dp, APP_FAIL, "PNG chunks changed from 0x%lx to 0x%lx",
+            (unsigned long)dp->chunks, chunks);
+   }
+
+   /* rowbytes should be the same */
+   rowbytes = png_get_rowbytes(dp->read_pp, dp->read_ip);
+
+   /* NOTE: on 64-bit systems this may trash the top bits of rowbytes,
+    * which could lead to weird error messages.
+    */
+   if (rowbytes != dp->original_rowbytes)
+      display_log(dp, APP_ERROR, "PNG rowbytes changed from %lu to %lu",
+         (unsigned long)dp->original_rowbytes, (unsigned long)rowbytes);
+
+   /* The rows should be the same too, unless the applied transforms includes
+    * the shift transform, in which case low bits may have been lost.
+    */
+   {
+      png_bytepp rows = png_get_rows(dp->read_pp, dp->read_ip);
+      unsigned int mask;  /* mask (if not zero) for the final byte */
+
+      if (bit_depth < 8)
+      {
+         /* Need the stray bits at the end, this depends only on the low bits
+          * of the image width; overflow does not matter.  If the width is an
+          * exact multiple of 8 bits this gives a mask of 0, not 0xff.
+          */
+         mask = 0xff & (0xff00 >> ((bit_depth * width) & 7));
+      }
+
+      else
+         mask = 0;
+
+      if (rows == NULL)
+         display_log(dp, LIBPNG_BUG, "png_get_rows returned NULL");
+
+      if ((applied_transforms & PNG_TRANSFORM_SHIFT) == 0 ||
+         (dp->active_transforms & PNG_TRANSFORM_SHIFT) == 0 ||
+         color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         unsigned long y;
+
+         for (y=0; y<height; ++y)
+         {
+            png_bytep row = rows[y];
+            png_bytep orig = dp->original_rows[y];
+
+            if (memcmp(row, orig, rowbytes-(mask != 0)) != 0 || (mask != 0 &&
+               ((row[rowbytes-1] & mask) != (orig[rowbytes-1] & mask))))
+            {
+               size_t x;
+
+               /* Find the first error */
+               for (x=0; x<rowbytes-1; ++x) if (row[x] != orig[x])
+                  break;
+
+               display_log(dp, APP_FAIL,
+                  "byte(%lu,%lu) changed 0x%.2x -> 0x%.2x",
+                  (unsigned long)x, (unsigned long)y, orig[x], row[x]);
+               return 0; /* don't keep reporting failed rows on 'continue' */
+            }
+         }
+      }
+
+      else
+#     ifdef PNG_sBIT_SUPPORTED
+      {
+         unsigned long y;
+         int bpp;   /* bits-per-pixel then bytes-per-pixel */
+         /* components are up to 8 bytes in size */
+         png_byte sig_bits[8];
+         png_color_8p sBIT;
+
+         if (png_get_sBIT(dp->read_pp, dp->read_ip, &sBIT) != PNG_INFO_sBIT)
+            display_log(dp, INTERNAL_ERROR,
+               "active shift transform but no sBIT in file");
+
+         switch (color_type)
+         {
+            case PNG_COLOR_TYPE_GRAY:
+               sig_bits[0] = sBIT->gray;
+               bpp = bit_depth;
+               break;
+
+            case PNG_COLOR_TYPE_GA:
+               sig_bits[0] = sBIT->gray;
+               sig_bits[1] = sBIT->alpha;
+               bpp = 2 * bit_depth;
+               break;
+
+            case PNG_COLOR_TYPE_RGB:
+               sig_bits[0] = sBIT->red;
+               sig_bits[1] = sBIT->green;
+               sig_bits[2] = sBIT->blue;
+               bpp = 3 * bit_depth;
+               break;
+
+            case PNG_COLOR_TYPE_RGBA:
+               sig_bits[0] = sBIT->red;
+               sig_bits[1] = sBIT->green;
+               sig_bits[2] = sBIT->blue;
+               sig_bits[3] = sBIT->alpha;
+               bpp = 4 * bit_depth;
+               break;
+
+            default:
+               display_log(dp, LIBPNG_ERROR, "invalid colour type %d",
+                  color_type);
+               /*NOTREACHED*/
+               bpp = 0;
+               break;
+         }
+
+         {
+            int b;
+
+            for (b=0; 8*b<bpp; ++b)
+            {
+               /* libpng should catch this; if not there is a security issue
+                * because an app (like this one) may overflow an array. In fact
+                * libpng doesn't catch this at present.
+                */
+               if (sig_bits[b] == 0 || sig_bits[b] > bit_depth/*!palette*/)
+                  display_log(dp, LIBPNG_BUG,
+                     "invalid sBIT[%u]  value %d returned for PNG bit depth %d",
+                     b, sig_bits[b], bit_depth);
+            }
+         }
+
+         if (bpp < 8 && bpp != bit_depth)
+         {
+            /* sanity check; this is a grayscale PNG; something is wrong in the
+             * code above.
+             */
+            display_log(dp, INTERNAL_ERROR, "invalid bpp %u for bit_depth %u",
+               bpp, bit_depth);
+         }
+
+         switch (bit_depth)
+         {
+            int b;
+
+            case 16: /* Two bytes per component, big-endian */
+               for (b = (bpp >> 4); b > 0; --b)
+               {
+                  unsigned int sig = (unsigned int)(0xffff0000 >> sig_bits[b]);
+
+                  sig_bits[2*b+1] = (png_byte)sig;
+                  sig_bits[2*b+0] = (png_byte)(sig >> 8); /* big-endian */
+               }
+               break;
+
+            case 8: /* One byte per component */
+               for (b=0; b*8 < bpp; ++b)
+                  sig_bits[b] = (png_byte)(0xff00 >> sig_bits[b]);
+               break;
+
+            case 1: /* allowed, but dumb */
+               /* Value is 1 */
+               sig_bits[0] = 0xff;
+               break;
+
+            case 2: /* Replicate 4 times */
+               /* Value is 1 or 2 */
+               b = 0x3 & ((0x3<<2) >> sig_bits[0]);
+               b |= b << 2;
+               b |= b << 4;
+               sig_bits[0] = (png_byte)b;
+               break;
+
+            case 4: /* Relicate twice */
+               /* Value is 1, 2, 3 or 4 */
+               b = 0xf & ((0xf << 4) >> sig_bits[0]);
+               b |= b << 4;
+               sig_bits[0] = (png_byte)b;
+               break;
+
+            default:
+               display_log(dp, LIBPNG_BUG, "invalid bit depth %d", bit_depth);
+               break;
+         }
+
+         /* Convert bpp to bytes; this gives '1' for low-bit depth grayscale,
+          * where there are multiple pixels per byte.
+          */
+         bpp = (bpp+7) >> 3;
+
+         /* The mask can be combined with sig_bits[0] */
+         if (mask != 0)
+         {
+            mask &= sig_bits[0];
+
+            if (bpp != 1 || mask == 0)
+               display_log(dp, INTERNAL_ERROR, "mask calculation error %u, %u",
+                  bpp, mask);
+         }
+
+         for (y=0; y<height; ++y)
+         {
+            png_bytep row = rows[y];
+            png_bytep orig = dp->original_rows[y];
+            unsigned long x;
+
+            for (x=0; x<(width-(mask!=0)); ++x)
+            {
+               int b;
+
+               for (b=0; b<bpp; ++b)
+               {
+                  if ((*row++ & sig_bits[b]) != (*orig++ & sig_bits[b]))
+                  {
+                     display_log(dp, APP_FAIL,
+                        "significant bits at (%lu[%u],%lu) changed %.2x->%.2x",
+                        x, b, y, orig[-1], row[-1]);
+                     return 0;
+                  }
+               }
+            }
+
+            if (mask != 0 && (*row & mask) != (*orig & mask))
+            {
+               display_log(dp, APP_FAIL,
+                  "significant bits at (%lu[end],%lu) changed", x, y);
+               return 0;
+            }
+         } /* for y */
+      }
+#     else /* !sBIT */
+         display_log(dp, INTERNAL_ERROR,
+               "active shift transform but no sBIT support");
+#     endif /* !sBIT */
+   }
+
+   return 1; /* compare succeeded */
+}
+
+#ifdef PNG_WRITE_PNG_SUPPORTED
+static void
+buffer_write(struct display *dp, struct buffer *buffer, png_bytep data,
+   size_t size)
+   /* Generic write function used both from the write callback provided to
+    * libpng and from the generic read code.
+    */
+{
+   /* Write the data into the buffer, adding buffers as required */
+   struct buffer_list *last = buffer->last;
+   size_t end_count = buffer->end_count;
+
+   while (size > 0)
+   {
+      size_t avail;
+
+      if (end_count >= sizeof last->buffer)
+      {
+         if (last->next == NULL)
+         {
+            last = buffer_extend(last);
+
+            if (last == NULL)
+               display_log(dp, APP_ERROR, "out of memory saving file");
+         }
+
+         else
+            last = last->next;
+
+         buffer->last = last; /* avoid the need to rewrite every time */
+         end_count = 0;
+      }
+
+      avail = (sizeof last->buffer) - end_count;
+      if (avail > size)
+         avail = size;
+
+      memcpy(last->buffer + end_count, data, avail);
+      end_count += avail;
+      size -= avail;
+      data += avail;
+   }
+
+   buffer->end_count = end_count;
+}
+
+static void PNGCBAPI
+write_function(png_structp pp, png_bytep data, size_t size)
+{
+   buffer_write(get_dp(pp), get_buffer(pp), data, size);
+}
+
+static void
+write_png(struct display *dp, png_infop ip, int transforms)
+{
+   display_clean_write(dp); /* safety */
+
+   buffer_start_write(&dp->written_file);
+   dp->operation = "write";
+   dp->transforms = transforms;
+
+   dp->write_pp = png_create_write_struct(PNG_LIBPNG_VER_STRING, dp,
+      display_error, display_warning);
+
+   if (dp->write_pp == NULL)
+      display_log(dp, APP_ERROR, "failed to create write png_struct");
+
+   png_set_write_fn(dp->write_pp, &dp->written_file, write_function,
+      NULL/*flush*/);
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      /* Remove the user limits, if any */
+      png_set_user_limits(dp->write_pp, 0x7fffffff, 0x7fffffff);
+#  endif
+
+   /* Certain transforms require the png_info to be zapped to allow the
+    * transform to work correctly.
+    */
+   if (transforms & (PNG_TRANSFORM_PACKING|
+                     PNG_TRANSFORM_STRIP_FILLER|
+                     PNG_TRANSFORM_STRIP_FILLER_BEFORE))
+   {
+      int ct = dp->color_type;
+
+      if (transforms & (PNG_TRANSFORM_STRIP_FILLER|
+                        PNG_TRANSFORM_STRIP_FILLER_BEFORE))
+         ct &= ~PNG_COLOR_MASK_ALPHA;
+
+      png_set_IHDR(dp->write_pp, ip, dp->width, dp->height, dp->bit_depth, ct,
+         dp->interlace_method, dp->compression_method, dp->filter_method);
+   }
+
+   png_write_png(dp->write_pp, ip, transforms, NULL/*params*/);
+
+   /* Clean it on the way out - if control returns to the caller then the
+    * written_file contains the required data.
+    */
+   display_clean_write(dp);
+}
+#endif /* WRITE_PNG */
+
+static int
+skip_transform(struct display *dp, int tr)
+   /* Helper to test for a bad combo and log it if it is skipped */
+{
+   if ((dp->options & SKIP_BUGS) != 0 && is_bad_combo(tr))
+   {
+      /* Log this to stdout if logging is on, otherwise just do an information
+       * display_log.
+       */
+      if ((dp->options & LOG_SKIPPED) != 0)
+      {
+         printf("SKIP: %s transforms ", dp->filename);
+
+         while (tr != 0)
+         {
+            int next = first_transform(tr);
+            tr &= ~next;
+
+            printf("%s", transform_name(next));
+            if (tr != 0)
+               putchar('+');
+         }
+
+         putchar('\n');
+      }
+
+      else
+         display_log(dp, INFORMATION, "%s: skipped known bad combo 0x%x",
+            dp->filename, tr);
+
+      return 1; /* skip */
+   }
+
+   return 0; /* don't skip */
+}
+
+static void
+test_one_file(struct display *dp, const char *filename)
+{
+   /* First cache the file and update the display original file
+    * information for the new file.
+    */
+   dp->operation = "cache file";
+   dp->transforms = 0;
+   display_cache_file(dp, filename);
+   update_display(dp);
+
+   /* First test: if there are options that should be ignored for this file
+    * verify that they really are ignored.
+    */
+   if (dp->ignored_transforms != 0)
+   {
+      read_png(dp, &dp->original_file, "ignored transforms",
+         dp->ignored_transforms);
+
+      /* The result should be identical to the original_rows */
+      if (!compare_read(dp, 0/*transforms applied*/))
+         return; /* no point testing more */
+   }
+
+#ifdef PNG_WRITE_PNG_SUPPORTED
+   /* Second test: write the original PNG data out to a new file (to test the
+    * write side) then read the result back in and make sure that it hasn't
+    * changed.
+    */
+   dp->operation = "write";
+   write_png(dp, dp->original_ip, 0/*transforms*/);
+   read_png(dp, &dp->written_file, NULL, 0/*transforms*/);
+   if (!compare_read(dp, 0/*transforms applied*/))
+      return;
+#endif
+
+   /* Third test: the active options.  Test each in turn, or, with the
+    * EXHAUSTIVE option, test all possible combinations.
+    */
+   {
+      /* Use unsigned int here because the code below to increment through all
+       * the possibilities exhaustively has to use a compare and that must be
+       * unsigned, because some transforms are negative on a 16-bit system.
+       */
+      unsigned int active = dp->active_transforms;
+      int exhaustive = (dp->options & EXHAUSTIVE) != 0;
+      unsigned int current = first_transform(active);
+      unsigned int bad_transforms = 0;
+      unsigned int bad_combo = ~0U;    /* bitwise AND of failing transforms */
+      unsigned int bad_combo_list = 0; /* bitwise OR of failures */
+
+      for (;;)
+      {
+         read_png(dp, &dp->original_file, "active transforms", current);
+
+         /* If this involved any irreversible transformations then if we write
+          * it out with just the reversible transformations and read it in again
+          * with the same transforms we should get the same thing.  At present
+          * this isn't done - it just seems like a waste of time and it would
+          * require two sets of read png_struct/png_info.
+          *
+          * If there were no irreversible transformations then if we write it
+          * out and read it back in again (without the reversible transforms)
+          * we should get back to the place where we started.
+          */
+#ifdef PNG_WRITE_PNG_SUPPORTED
+         if ((current & write_transforms) == current)
+         {
+            /* All transforms reversible: write the PNG with the transformations
+             * reversed, then read it back in with no transformations.  The
+             * result should be the same as the original apart from the loss of
+             * low order bits because of the SHIFT/sBIT transform.
+             */
+            dp->operation = "reversible transforms";
+            write_png(dp, dp->read_ip, current);
+
+            /* And if this is read back in, because all the transformations were
+             * reversible, the result should be the same.
+             */
+            read_png(dp, &dp->written_file, NULL, 0);
+            if (!compare_read(dp, current/*for the SHIFT/sBIT transform*/))
+            {
+               /* This set of transforms failed.  If a single bit is set - if
+                * there is just one transform - don't include this in further
+                * 'exhaustive' tests.  Notice that each transform is tested on
+                * its own before testing combos in the exhaustive case.
+                */
+               if (is_combo(current))
+               {
+                  bad_combo &= current;
+                  bad_combo_list |= current;
+               }
+
+               else
+                  bad_transforms |= current;
+            }
+         }
+#endif
+
+         /* Now move to the next transform */
+         if (exhaustive) /* all combinations */
+         {
+            unsigned int next = current;
+
+            do
+            {
+               if (next == read_transforms) /* Everything tested */
+                  goto combo;
+
+               ++next;
+            }  /* skip known bad combos if the relevant option is set; skip
+                * combos involving known bad single transforms in all cases.
+                */
+            while (  (next & read_transforms) <= current
+                  || (next & active) == 0 /* skip cases that do nothing */
+                  || (next & bad_transforms) != 0
+                  || skip_transform(dp, next));
+
+            assert((next & read_transforms) == next);
+            current = next;
+         }
+
+         else /* one at a time */
+         {
+            active &= ~current;
+
+            if (active == 0)
+               goto combo;
+
+            current = first_transform(active);
+         }
+      }
+
+combo:
+      if (dp->options & FIND_BAD_COMBOS)
+      {
+         /* bad_combos identifies the combos that occur in all failing cases;
+          * bad_combo_list identifies transforms that do not prevent the
+          * failure.
+          */
+         if (bad_combo != ~0U)
+            printf("%s[0x%x]: PROBLEM: 0x%x[0x%x] ANTIDOTE: 0x%x\n",
+               dp->filename, active, bad_combo, bad_combo_list,
+               rw_transforms & ~bad_combo_list);
+
+         else
+            printf("%s: no %sbad combos found\n", dp->filename,
+               (dp->options & SKIP_BUGS) ? "additional " : "");
+      }
+   }
+}
+
+static int
+do_test(struct display *dp, const char *file)
+   /* Exists solely to isolate the setjmp clobbers */
+{
+   int ret = setjmp(dp->error_return);
+
+   if (ret == 0)
+   {
+      test_one_file(dp, file);
+      return 0;
+   }
+
+   else if (ret < ERRORS) /* shouldn't longjmp on warnings */
+      display_log(dp, INTERNAL_ERROR, "unexpected return code %d", ret);
+
+   return ret;
+}
+
+int
+main(int argc, char **argv)
+{
+   /* For each file on the command line test it with a range of transforms */
+   int option_end, ilog = 0;
+   struct display d;
+
+   validate_T();
+   display_init(&d);
+
+   for (option_end=1; option_end<argc; ++option_end)
+   {
+      const char *name = argv[option_end];
+
+      if (strcmp(name, "--verbose") == 0)
+         d.options = (d.options & ~LEVEL_MASK) | VERBOSE;
+
+      else if (strcmp(name, "--warnings") == 0)
+         d.options = (d.options & ~LEVEL_MASK) | WARNINGS;
+
+      else if (strcmp(name, "--errors") == 0)
+         d.options = (d.options & ~LEVEL_MASK) | ERRORS;
+
+      else if (strcmp(name, "--quiet") == 0)
+         d.options = (d.options & ~LEVEL_MASK) | QUIET;
+
+      else if (strcmp(name, "--exhaustive") == 0)
+         d.options |= EXHAUSTIVE;
+
+      else if (strcmp(name, "--fast") == 0)
+         d.options &= ~EXHAUSTIVE;
+
+      else if (strcmp(name, "--strict") == 0)
+         d.options |= STRICT;
+
+      else if (strcmp(name, "--relaxed") == 0)
+         d.options &= ~STRICT;
+
+      else if (strcmp(name, "--log") == 0)
+      {
+         ilog = option_end; /* prevent display */
+         d.options |= LOG;
+      }
+
+      else if (strcmp(name, "--nolog") == 0)
+         d.options &= ~LOG;
+
+      else if (strcmp(name, "--continue") == 0)
+         d.options |= CONTINUE;
+
+      else if (strcmp(name, "--stop") == 0)
+         d.options &= ~CONTINUE;
+
+      else if (strcmp(name, "--skip-bugs") == 0)
+         d.options |= SKIP_BUGS;
+
+      else if (strcmp(name, "--test-all") == 0)
+         d.options &= ~SKIP_BUGS;
+
+      else if (strcmp(name, "--log-skipped") == 0)
+         d.options |= LOG_SKIPPED;
+
+      else if (strcmp(name, "--nolog-skipped") == 0)
+         d.options &= ~LOG_SKIPPED;
+
+      else if (strcmp(name, "--find-bad-combos") == 0)
+         d.options |= FIND_BAD_COMBOS;
+
+      else if (strcmp(name, "--nofind-bad-combos") == 0)
+         d.options &= ~FIND_BAD_COMBOS;
+
+      else if (strcmp(name, "--list-combos") == 0)
+         d.options |= LIST_COMBOS;
+
+      else if (strcmp(name, "--nolist-combos") == 0)
+         d.options &= ~LIST_COMBOS;
+
+      else if (name[0] == '-' && name[1] == '-')
+      {
+         fprintf(stderr, "pngimage: %s: unknown option\n", name);
+         return 99;
+      }
+
+      else
+         break; /* Not an option */
+   }
+
+   {
+      int i;
+      int errors = 0;
+
+      for (i=option_end; i<argc; ++i)
+      {
+         {
+            int ret = do_test(&d, argv[i]);
+
+            if (ret > QUIET) /* abort on user or internal error */
+               return 99;
+         }
+
+         /* Here on any return, including failures, except user/internal issues
+          */
+         {
+            int pass = (d.options & STRICT) ?
+               RESULT_STRICT(d.results) : RESULT_RELAXED(d.results);
+
+            if (!pass)
+               ++errors;
+
+            if (d.options & LOG)
+            {
+               int j;
+
+               printf("%s: pngimage ", pass ? "PASS" : "FAIL");
+
+               for (j=1; j<option_end; ++j) if (j != ilog)
+                  printf("%s ", argv[j]);
+
+               printf("%s\n", d.filename);
+            }
+         }
+
+         display_clean(&d);
+      }
+
+      /* Release allocated memory */
+      display_destroy(&d);
+
+      return errors != 0;
+   }
+}
+#else /* !READ_PNG */
+int
+main(void)
+{
+   fprintf(stderr, "pngimage: no support for png_read/write_image\n");
+   return SKIP;
+}
+#endif
diff --git a/extern/libpng/contrib/libtests/pngstest-errors.h b/extern/libpng/contrib/libtests/pngstest-errors.h
new file mode 100644
index 0000000000..3356f1c46f
--- /dev/null
+++ b/extern/libpng/contrib/libtests/pngstest-errors.h
@@ -0,0 +1,165 @@
+/* contrib/libtests/pngstest-errors.h
+ *
+ * BUILT USING: libpng version 1.6.19beta03 - September 25, 2015
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * THIS IS A MACHINE GENERATED FILE: do not edit it directly!
+ * Instead run:
+ *
+ *    pngstest --accumulate
+ *
+ * on as many PNG files as possible; at least PNGSuite and
+ * contrib/libtests/testpngs.
+ */
+static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =
+{
+ { /* input: sRGB-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: sRGB-gray+alpha */
+  { 0, 19, 0, 0 }, { 0, 0, 0, 0 }, { 0, 20, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: sRGB-rgb */
+  { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 893, 0 }, { 0, 0, 893, 0 }, { 0, 0, 811, 0 }, { 0, 0, 811, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: sRGB-rgb+alpha */
+  { 0, 16, 17, 0 }, { 0, 17, 17, 0 }, { 0, 19, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 850, 875, 0 }, { 0, 850, 875, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-gray */
+  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-gray+alpha */
+  { 0, 74, 9, 0 }, { 0, 20, 9, 0 }, { 0, 74, 9, 0 }, { 0, 20, 9, 0 },
+  { 0, 0, 0, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-rgb */
+  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 4, 0 }, { 0, 0, 4, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-rgb+alpha */
+  { 0, 126, 143, 0 }, { 0, 11, 7, 0 }, { 0, 74, 9, 0 }, { 0, 17, 9, 0 },
+  { 0, 4, 4, 0 }, { 0, 5, 4, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-rgb */
+  { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 673, 0 }, { 0, 0, 673, 0 }, { 0, 0, 674, 0 }, { 0, 0, 674, 0 },
+  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 460, 0 }, { 0, 0, 460, 0 }, { 0, 0, 263, 0 }, { 0, 0, 263, 0 }
+ }, { /* input: color-mapped-sRGB-rgb+alpha */
+  { 0, 6, 8, 0 }, { 0, 7, 8, 0 }, { 0, 75, 9, 0 }, { 0, 9, 9, 0 },
+  { 0, 585, 427, 0 }, { 0, 585, 427, 0 }, { 0, 717, 514, 0 }, { 0, 717, 514, 0 },
+  { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 13323, 460, 0 }, { 0, 427, 460, 0 }, { 0, 16480, 263, 0 }, { 0, 243, 263, 0 }
+ }, { /* input: color-mapped-linear-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 253, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 265, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 243, 265, 0 }
+ }
+};
+static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =
+{
+ { /* input: sRGB-gray */
+  { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }
+ }, { /* input: sRGB-gray+alpha */
+  { 0, 15, 15, 0 }, { 0, 186, 15, 0 }, { 0, 15, 15, 0 }, { 0, 186, 15, 0 }
+ }, { /* input: sRGB-rgb */
+  { 0, 0, 20, 0 }, { 0, 0, 20, 0 }, { 0, 0, 15, 0 }, { 0, 0, 15, 0 }
+ }, { /* input: sRGB-rgb+alpha */
+  { 0, 16, 17, 0 }, { 0, 187, 17, 0 }, { 0, 15, 15, 0 }, { 0, 186, 15, 0 }
+ }, { /* input: linear-gray */
+  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
+ }, { /* input: linear-gray+alpha */
+  { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
+ }, { /* input: linear-rgb */
+  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
+ }, { /* input: linear-rgb+alpha */
+  { 0, 1, 1, 0 }, { 0, 9, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
+ }, { /* input: color-mapped-sRGB-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-rgb */
+  { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 14, 0 }, { 0, 0, 14, 0 }
+ }, { /* input: color-mapped-sRGB-rgb+alpha */
+  { 0, 4, 8, 0 }, { 0, 9, 8, 0 }, { 0, 9, 5, 0 }, { 0, 32, 5, 0 }
+ }, { /* input: color-mapped-linear-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }
+};
+static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =
+{
+ { /* input: sRGB-gray */
+  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }
+ }, { /* input: sRGB-gray+alpha */
+  { 0, 19, 9, 0 }, { 0, 255, 9, 25 }, { 0, 88, 9, 0 }, { 0, 255, 9, 25 },
+  { 0, 1012, 928, 0 }, { 0, 16026, 928, 6425 }, { 0, 1012, 928, 0 }, { 0, 16026, 928, 6425 }
+ }, { /* input: sRGB-rgb */
+  { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 25, 0 }, { 0, 0, 25, 0 },
+  { 0, 0, 962, 0 }, { 0, 0, 962, 0 }, { 0, 0, 13677, 0 }, { 0, 0, 13677, 0 }
+ }, { /* input: sRGB-rgb+alpha */
+  { 0, 63, 77, 0 }, { 0, 255, 19, 25 }, { 0, 225, 25, 0 }, { 0, 255, 25, 67 },
+  { 0, 17534, 18491, 0 }, { 0, 15736, 2824, 6425 }, { 0, 14019, 13677, 0 }, { 0, 50115, 13677, 17219 }
+ }, { /* input: linear-gray */
+  { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 },
+  { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }
+ }, { /* input: linear-gray+alpha */
+  { 0, 74, 74, 0 }, { 0, 255, 74, 25 }, { 0, 99, 74, 0 }, { 0, 255, 74, 25 },
+  { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6553 }, { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6553 }
+ }, { /* input: linear-rgb */
+  { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 98, 0 }, { 0, 0, 98, 0 },
+  { 0, 0, 18664, 0 }, { 0, 0, 18664, 0 }, { 0, 0, 24998, 0 }, { 0, 0, 24998, 0 }
+ }, { /* input: linear-rgb+alpha */
+  { 0, 181, 196, 0 }, { 0, 255, 61, 25 }, { 206, 187, 98, 0 }, { 0, 255, 98, 67 },
+  { 0, 18141, 18137, 0 }, { 0, 17494, 17504, 6553 }, { 0, 24979, 24992, 0 }, { 0, 49172, 24992, 17347 }
+ }
+};
+/* END MACHINE GENERATED */
diff --git a/extern/libpng/contrib/libtests/pngstest.c b/extern/libpng/contrib/libtests/pngstest.c
new file mode 100644
index 0000000000..a368bf0f4d
--- /dev/null
+++ b/extern/libpng/contrib/libtests/pngstest.c
@@ -0,0 +1,3828 @@
+/*-
+ * pngstest.c
+ *
+ * Last changed in libpng 1.6.31 [July 27, 2017]
+ * Copyright (c) 2013-2017 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Test for the PNG 'simplified' APIs.
+ */
+#define _ISOC90_SOURCE 1
+#define MALLOC_CHECK_ 2/*glibc facility: turn on debugging*/
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <ctype.h>
+#include <math.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED /* Else nothing can be done */
+#include "../tools/sRGB.h"
+
+/* KNOWN ISSUES
+ *
+ * These defines switch on alternate algorithms for format conversions to match
+ * the current libpng implementation; they are set to allow pngstest to pass
+ * even though libpng is producing answers that are not as correct as they
+ * should be.
+ */
+#define ALLOW_UNUSED_GPC 0
+   /* If true include unused static GPC functions and declare an external array
+    * of them to hide the fact that they are unused.  This is for development
+    * use while testing the correct function to use to take into account libpng
+    * misbehavior, such as using a simple power law to correct sRGB to linear.
+    */
+
+/* The following is to support direct compilation of this file as C++ */
+#ifdef __cplusplus
+#  define voidcast(type, value) static_cast<type>(value)
+#  define aligncastconst(type, value) \
+      static_cast<type>(static_cast<const void*>(value))
+#else
+#  define voidcast(type, value) (value)
+#  define aligncastconst(type, value) ((const void*)(value))
+#endif /* __cplusplus */
+
+/* During parallel runs of pngstest each temporary file needs a unique name,
+ * this is used to permit uniqueness using a command line argument which can be
+ * up to 22 characters long.
+ */
+static char tmpf[23] = "TMP";
+
+/* Generate random bytes.  This uses a boring repeatable algorithm and it
+ * is implemented here so that it gives the same set of numbers on every
+ * architecture.  It's a linear congruential generator (Knuth or Sedgewick
+ * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
+ * Hill, "The Art of Electronics".
+ */
+static void
+make_random_bytes(png_uint_32* seed, void* pv, size_t size)
+{
+   png_uint_32 u0 = seed[0], u1 = seed[1];
+   png_bytep bytes = voidcast(png_bytep, pv);
+
+   /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
+    * bit-20.  The top 1 bit is in u1, the bottom 32 are in u0.
+    */
+   size_t i;
+   for (i=0; i<size; ++i)
+   {
+      /* First generate 8 new bits then shift them in at the end. */
+      png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
+      u1 <<= 8;
+      u1 |= u0 >> 24;
+      u0 <<= 8;
+      u0 |= u;
+      *bytes++ = (png_byte)u;
+   }
+
+   seed[0] = u0;
+   seed[1] = u1;
+}
+
+static png_uint_32 color_seed[2];
+
+static void
+reseed(void)
+{
+   color_seed[0] = 0x12345678U;
+   color_seed[1] = 0x9abcdefU;
+}
+
+static void
+random_color(png_colorp color)
+{
+   make_random_bytes(color_seed, color, sizeof *color);
+}
+
+/* Math support - neither Cygwin nor Visual Studio have C99 support and we need
+ * a predictable rounding function, so make one here:
+ */
+static double
+closestinteger(double x)
+{
+   return floor(x + .5);
+}
+
+/* Cast support: remove GCC whines. */
+static png_byte
+u8d(double d)
+{
+   d = closestinteger(d);
+   return (png_byte)d;
+}
+
+static png_uint_16
+u16d(double d)
+{
+   d = closestinteger(d);
+   return (png_uint_16)d;
+}
+
+/* sRGB support: use exact calculations rounded to the nearest int, see the
+ * fesetround() call in main().  sRGB_to_d optimizes the 8 to 16-bit conversion.
+ */
+static double sRGB_to_d[256];
+static double g22_to_d[256];
+
+static void
+init_sRGB_to_d(void)
+{
+   int i;
+
+   sRGB_to_d[0] = 0;
+   for (i=1; i<255; ++i)
+      sRGB_to_d[i] = linear_from_sRGB(i/255.);
+   sRGB_to_d[255] = 1;
+
+   g22_to_d[0] = 0;
+   for (i=1; i<255; ++i)
+      g22_to_d[i] = pow(i/255., 1/.45455);
+   g22_to_d[255] = 1;
+}
+
+static png_byte
+sRGB(double linear /*range 0.0 .. 1.0*/)
+{
+   return u8d(255 * sRGB_from_linear(linear));
+}
+
+static png_byte
+isRGB(int fixed_linear)
+{
+   return sRGB(fixed_linear / 65535.);
+}
+
+#if 0 /* not used */
+static png_byte
+unpremultiply(int component, int alpha)
+{
+   if (alpha <= component)
+      return 255; /* Arbitrary, but consistent with the libpng code */
+
+   else if (alpha >= 65535)
+      return isRGB(component);
+
+   else
+      return sRGB((double)component / alpha);
+}
+#endif
+
+static png_uint_16
+ilinear(int fixed_srgb)
+{
+   return u16d(65535 * sRGB_to_d[fixed_srgb]);
+}
+
+static png_uint_16
+ilineara(int fixed_srgb, int alpha)
+{
+   return u16d((257 * alpha) * sRGB_to_d[fixed_srgb]);
+}
+
+static png_uint_16
+ilinear_g22(int fixed_srgb)
+{
+   return u16d(65535 * g22_to_d[fixed_srgb]);
+}
+
+#if ALLOW_UNUSED_GPC
+static png_uint_16
+ilineara_g22(int fixed_srgb, int alpha)
+{
+   return u16d((257 * alpha) * g22_to_d[fixed_srgb]);
+}
+#endif
+
+static double
+YfromRGBint(int ir, int ig, int ib)
+{
+   double r = ir;
+   double g = ig;
+   double b = ib;
+   return YfromRGB(r, g, b);
+}
+
+#if 0 /* unused */
+/* The error that results from using a 2.2 power law in place of the correct
+ * sRGB transform, given an 8-bit value which might be either sRGB or power-law.
+ */
+static int
+power_law_error8(int value)
+{
+   if (value > 0 && value < 255)
+   {
+      double vd = value / 255.;
+      double e = fabs(
+         pow(sRGB_to_d[value], 1/2.2) - sRGB_from_linear(pow(vd, 2.2)));
+
+      /* Always allow an extra 1 here for rounding errors */
+      e = 1+floor(255 * e);
+      return (int)e;
+   }
+
+   return 0;
+}
+
+static int error_in_sRGB_roundtrip = 56; /* by experiment */
+static int
+power_law_error16(int value)
+{
+   if (value > 0 && value < 65535)
+   {
+      /* Round trip the value through an 8-bit representation but using
+       * non-matching to/from conversions.
+       */
+      double vd = value / 65535.;
+      double e = fabs(
+         pow(sRGB_from_linear(vd), 2.2) - linear_from_sRGB(pow(vd, 1/2.2)));
+
+      /* Always allow an extra 1 here for rounding errors */
+      e = error_in_sRGB_roundtrip+floor(65535 * e);
+      return (int)e;
+   }
+
+   return 0;
+}
+
+static int
+compare_8bit(int v1, int v2, int error_limit, int multiple_algorithms)
+{
+   int e = abs(v1-v2);
+   int ev1, ev2;
+
+   if (e <= error_limit)
+      return 1;
+
+   if (!multiple_algorithms)
+      return 0;
+
+   ev1 = power_law_error8(v1);
+   if (e <= ev1)
+      return 1;
+
+   ev2 = power_law_error8(v2);
+   if (e <= ev2)
+      return 1;
+
+   return 0;
+}
+
+static int
+compare_16bit(int v1, int v2, int error_limit, int multiple_algorithms)
+{
+   int e = abs(v1-v2);
+   int ev1, ev2;
+
+   if (e <= error_limit)
+      return 1;
+
+   /* "multiple_algorithms" in this case means that a color-map has been
+    * involved somewhere, so we can deduce that the values were forced to 8-bit
+    * (like the via_linear case for 8-bit.)
+    */
+   if (!multiple_algorithms)
+      return 0;
+
+   ev1 = power_law_error16(v1);
+   if (e <= ev1)
+      return 1;
+
+   ev2 = power_law_error16(v2);
+   if (e <= ev2)
+      return 1;
+
+   return 0;
+}
+#endif /* unused */
+
+#define USE_FILE 1       /* else memory */
+#define USE_STDIO 2      /* else use file name */
+#define STRICT 4         /* fail on warnings too */
+#define VERBOSE 8
+#define KEEP_TMPFILES 16 /* else delete temporary files */
+#define KEEP_GOING 32
+#define ACCUMULATE 64
+#define FAST_WRITE 128
+#define sRGB_16BIT 256
+#define NO_RESEED  512   /* do not reseed on each new file */
+#define GBG_ERROR 1024   /* do not ignore the gamma+background_rgb_to_gray
+                          * libpng warning. */
+
+static void
+print_opts(png_uint_32 opts)
+{
+   if (opts & USE_FILE)
+      printf(" --file");
+   if (opts & USE_STDIO)
+      printf(" --stdio");
+   if (!(opts & STRICT))
+      printf(" --nostrict");
+   if (opts & VERBOSE)
+      printf(" --verbose");
+   if (opts & KEEP_TMPFILES)
+      printf(" --preserve");
+   if (opts & KEEP_GOING)
+      printf(" --keep-going");
+   if (opts & ACCUMULATE)
+      printf(" --accumulate");
+   if (!(opts & FAST_WRITE)) /* --fast is currently the default */
+      printf(" --slow");
+   if (opts & sRGB_16BIT)
+      printf(" --sRGB-16bit");
+   if (opts & NO_RESEED)
+      printf(" --noreseed");
+#if PNG_LIBPNG_VER < 10700 /* else on by default */
+   if (opts & GBG_ERROR)
+      printf(" --fault-gbg-warning");
+#endif
+}
+
+#define FORMAT_NO_CHANGE 0x80000000 /* additional flag */
+
+/* A name table for all the formats - defines the format of the '+' arguments to
+ * pngstest.
+ */
+#define FORMAT_COUNT 64
+#define FORMAT_MASK 0x3f
+static const char * const format_names[FORMAT_COUNT] =
+{
+   "sRGB-gray",
+   "sRGB-gray+alpha",
+   "sRGB-rgb",
+   "sRGB-rgb+alpha",
+   "linear-gray",
+   "linear-gray+alpha",
+   "linear-rgb",
+   "linear-rgb+alpha",
+
+   "color-mapped-sRGB-gray",
+   "color-mapped-sRGB-gray+alpha",
+   "color-mapped-sRGB-rgb",
+   "color-mapped-sRGB-rgb+alpha",
+   "color-mapped-linear-gray",
+   "color-mapped-linear-gray+alpha",
+   "color-mapped-linear-rgb",
+   "color-mapped-linear-rgb+alpha",
+
+   "sRGB-gray",
+   "sRGB-gray+alpha",
+   "sRGB-bgr",
+   "sRGB-bgr+alpha",
+   "linear-gray",
+   "linear-gray+alpha",
+   "linear-bgr",
+   "linear-bgr+alpha",
+
+   "color-mapped-sRGB-gray",
+   "color-mapped-sRGB-gray+alpha",
+   "color-mapped-sRGB-bgr",
+   "color-mapped-sRGB-bgr+alpha",
+   "color-mapped-linear-gray",
+   "color-mapped-linear-gray+alpha",
+   "color-mapped-linear-bgr",
+   "color-mapped-linear-bgr+alpha",
+
+   "sRGB-gray",
+   "alpha+sRGB-gray",
+   "sRGB-rgb",
+   "alpha+sRGB-rgb",
+   "linear-gray",
+   "alpha+linear-gray",
+   "linear-rgb",
+   "alpha+linear-rgb",
+
+   "color-mapped-sRGB-gray",
+   "color-mapped-alpha+sRGB-gray",
+   "color-mapped-sRGB-rgb",
+   "color-mapped-alpha+sRGB-rgb",
+   "color-mapped-linear-gray",
+   "color-mapped-alpha+linear-gray",
+   "color-mapped-linear-rgb",
+   "color-mapped-alpha+linear-rgb",
+
+   "sRGB-gray",
+   "alpha+sRGB-gray",
+   "sRGB-bgr",
+   "alpha+sRGB-bgr",
+   "linear-gray",
+   "alpha+linear-gray",
+   "linear-bgr",
+   "alpha+linear-bgr",
+
+   "color-mapped-sRGB-gray",
+   "color-mapped-alpha+sRGB-gray",
+   "color-mapped-sRGB-bgr",
+   "color-mapped-alpha+sRGB-bgr",
+   "color-mapped-linear-gray",
+   "color-mapped-alpha+linear-gray",
+   "color-mapped-linear-bgr",
+   "color-mapped-alpha+linear-bgr",
+};
+
+/* Decode an argument to a format number. */
+static png_uint_32
+formatof(const char *arg)
+{
+   char *ep;
+   unsigned long format = strtoul(arg, &ep, 0);
+
+   if (ep > arg && *ep == 0 && format < FORMAT_COUNT)
+      return (png_uint_32)format;
+
+   else for (format=0; format < FORMAT_COUNT; ++format)
+   {
+      if (strcmp(format_names[format], arg) == 0)
+         return (png_uint_32)format;
+   }
+
+   fprintf(stderr, "pngstest: format name '%s' invalid\n", arg);
+   return FORMAT_COUNT;
+}
+
+/* Bitset/test functions for formats */
+#define FORMAT_SET_COUNT (FORMAT_COUNT / 32)
+typedef struct
+{
+   png_uint_32 bits[FORMAT_SET_COUNT];
+}
+format_list;
+
+static void format_init(format_list *pf)
+{
+   int i;
+   for (i=0; i<FORMAT_SET_COUNT; ++i)
+      pf->bits[i] = 0; /* All off */
+}
+
+#if 0 /* currently unused */
+static void format_clear(format_list *pf)
+{
+   int i;
+   for (i=0; i<FORMAT_SET_COUNT; ++i)
+      pf->bits[i] = 0;
+}
+#endif
+
+static int format_is_initial(format_list *pf)
+{
+   int i;
+   for (i=0; i<FORMAT_SET_COUNT; ++i)
+      if (pf->bits[i] != 0)
+         return 0;
+
+   return 1;
+}
+
+static int format_set(format_list *pf, png_uint_32 format)
+{
+   if (format < FORMAT_COUNT)
+      return pf->bits[format >> 5] |= ((png_uint_32)1) << (format & 31);
+
+   return 0;
+}
+
+#if 0 /* currently unused */
+static int format_unset(format_list *pf, png_uint_32 format)
+{
+   if (format < FORMAT_COUNT)
+      return pf->bits[format >> 5] &= ~((png_uint_32)1) << (format & 31);
+
+   return 0;
+}
+#endif
+
+static int format_isset(format_list *pf, png_uint_32 format)
+{
+   return format < FORMAT_COUNT &&
+      (pf->bits[format >> 5] & (((png_uint_32)1) << (format & 31))) != 0;
+}
+
+static void format_default(format_list *pf, int redundant)
+{
+   if (redundant)
+   {
+      int i;
+
+      /* set everything, including flags that are pointless */
+      for (i=0; i<FORMAT_SET_COUNT; ++i)
+         pf->bits[i] = ~(png_uint_32)0;
+   }
+
+   else
+   {
+      png_uint_32 f;
+
+      for (f=0; f<FORMAT_COUNT; ++f)
+      {
+         /* Eliminate redundant and unsupported settings. */
+#        ifdef PNG_FORMAT_BGR_SUPPORTED
+            /* BGR is meaningless if no color: */
+            if ((f & PNG_FORMAT_FLAG_COLOR) == 0 &&
+               (f & PNG_FORMAT_FLAG_BGR) != 0)
+#        else
+            if ((f & 0x10U/*HACK: fixed value*/) != 0)
+#        endif
+            continue;
+
+         /* AFIRST is meaningless if no alpha: */
+#        ifdef PNG_FORMAT_AFIRST_SUPPORTED
+            if ((f & PNG_FORMAT_FLAG_ALPHA) == 0 &&
+               (f & PNG_FORMAT_FLAG_AFIRST) != 0)
+#        else
+            if ((f & 0x20U/*HACK: fixed value*/) != 0)
+#        endif
+            continue;
+
+         format_set(pf, f);
+      }
+   }
+}
+
+/* THE Image STRUCTURE */
+/* The super-class of a png_image, contains the decoded image plus the input
+ * data necessary to re-read the file with a different format.
+ */
+typedef struct
+{
+   png_image   image;
+   png_uint_32 opts;
+   const char *file_name;
+   int         stride_extra;
+   FILE       *input_file;
+   png_voidp   input_memory;
+   size_t      input_memory_size;
+   png_bytep   buffer;
+   ptrdiff_t   stride;
+   size_t      bufsize;
+   size_t      allocsize;
+   char        tmpfile_name[32];
+   png_uint_16 colormap[256*4];
+}
+Image;
+
+/* Initializer: also sets the permitted error limit for 16-bit operations. */
+static void
+newimage(Image *image)
+{
+   memset(image, 0, sizeof *image);
+}
+
+/* Reset the image to be read again - only needs to rewind the FILE* at present.
+ */
+static void
+resetimage(Image *image)
+{
+   if (image->input_file != NULL)
+      rewind(image->input_file);
+}
+
+/* Free the image buffer; the buffer is re-used on a re-read, this is just for
+ * cleanup.
+ */
+static void
+freebuffer(Image *image)
+{
+   if (image->buffer) free(image->buffer);
+   image->buffer = NULL;
+   image->bufsize = 0;
+   image->allocsize = 0;
+}
+
+/* Delete function; cleans out all the allocated data and the temporary file in
+ * the image.
+ */
+static void
+freeimage(Image *image)
+{
+   freebuffer(image);
+   png_image_free(&image->image);
+
+   if (image->input_file != NULL)
+   {
+      fclose(image->input_file);
+      image->input_file = NULL;
+   }
+
+   if (image->input_memory != NULL)
+   {
+      free(image->input_memory);
+      image->input_memory = NULL;
+      image->input_memory_size = 0;
+   }
+
+   if (image->tmpfile_name[0] != 0 && (image->opts & KEEP_TMPFILES) == 0)
+   {
+      (void)remove(image->tmpfile_name);
+      image->tmpfile_name[0] = 0;
+   }
+}
+
+/* This is actually a re-initializer; allows an image structure to be re-used by
+ * freeing everything that relates to an old image.
+ */
+static void initimage(Image *image, png_uint_32 opts, const char *file_name,
+   int stride_extra)
+{
+   freeimage(image);
+   memset(&image->image, 0, sizeof image->image);
+   image->opts = opts;
+   image->file_name = file_name;
+   image->stride_extra = stride_extra;
+}
+
+/* Make sure the image buffer is big enough; allows re-use of the buffer if the
+ * image is re-read.
+ */
+#define BUFFER_INIT8 73
+static void
+allocbuffer(Image *image)
+{
+   size_t size = PNG_IMAGE_BUFFER_SIZE(image->image, image->stride);
+
+   if (size+32 > image->bufsize)
+   {
+      freebuffer(image);
+      image->buffer = voidcast(png_bytep, malloc(size+32));
+      if (image->buffer == NULL)
+      {
+         fflush(stdout);
+         fprintf(stderr,
+            "simpletest: out of memory allocating %lu(+32) byte buffer\n",
+            (unsigned long)size);
+         exit(1);
+      }
+      image->bufsize = size+32;
+   }
+
+   memset(image->buffer, 95, image->bufsize);
+   memset(image->buffer+16, BUFFER_INIT8, size);
+   image->allocsize = size;
+}
+
+/* Make sure 16 bytes match the given byte. */
+static int
+check16(png_const_bytep bp, int b)
+{
+   int i = 16;
+
+   do
+      if (*bp != b) return 1;
+   while (--i);
+
+   return 0;
+}
+
+/* Check for overwrite in the image buffer. */
+static void
+checkbuffer(Image *image, const char *arg)
+{
+   if (check16(image->buffer, 95))
+   {
+      fflush(stdout);
+      fprintf(stderr, "%s: overwrite at start of image buffer\n", arg);
+      exit(1);
+   }
+
+   if (check16(image->buffer+16+image->allocsize, 95))
+   {
+      fflush(stdout);
+      fprintf(stderr, "%s: overwrite at end of image buffer\n", arg);
+      exit(1);
+   }
+}
+
+/* ERROR HANDLING */
+/* Log a terminal error, also frees the libpng part of the image if necessary.
+ */
+static int
+logerror(Image *image, const char *a1, const char *a2, const char *a3)
+{
+   fflush(stdout);
+   if (image->image.warning_or_error)
+      fprintf(stderr, "%s%s%s: %s\n", a1, a2, a3, image->image.message);
+
+   else
+      fprintf(stderr, "%s%s%s\n", a1, a2, a3);
+
+   if (image->image.opaque != NULL)
+   {
+      fprintf(stderr, "%s: image opaque pointer non-NULL on error\n",
+         image->file_name);
+      png_image_free(&image->image);
+   }
+
+   return 0;
+}
+
+/* Log an error and close a file (just a utility to do both things in one
+ * function call.)
+ */
+static int
+logclose(Image *image, FILE *f, const char *name, const char *operation)
+{
+   int e = errno;
+
+   fclose(f);
+   return logerror(image, name, operation, strerror(e));
+}
+
+/* Make sure the png_image has been freed - validates that libpng is doing what
+ * the spec says and freeing the image.
+ */
+static int
+checkopaque(Image *image)
+{
+   if (image->image.opaque != NULL)
+   {
+      png_image_free(&image->image);
+      return logerror(image, image->file_name, ": opaque not NULL", "");
+   }
+
+   /* Separate out the gamma+background_rgb_to_gray warning because it may
+    * produce opaque component errors:
+    */
+   else if (image->image.warning_or_error != 0 &&
+            (strcmp(image->image.message,
+               "libpng does not support gamma+background+rgb_to_gray") == 0 ?
+                  (image->opts & GBG_ERROR) != 0 : (image->opts & STRICT) != 0))
+      return logerror(image, image->file_name, (image->opts & GBG_ERROR) != 0 ?
+                      " --fault-gbg-warning" : " --strict", "");
+
+   else
+      return 1;
+}
+
+/* IMAGE COMPARISON/CHECKING */
+/* Compare the pixels of two images, which should be the same but aren't.  The
+ * images must have been checked for a size match.
+ */
+typedef struct
+{
+   /* The components, for grayscale images the gray value is in 'g' and if alpha
+    * is not present 'a' is set to 255 or 65535 according to format.
+    */
+   int         r, g, b, a;
+} Pixel;
+
+typedef struct
+{
+   /* The background as the original sRGB 8-bit value converted to the final
+    * integer format and as a double precision linear value in the range 0..1
+    * for with partially transparent pixels.
+    */
+   int ir, ig, ib;
+   double dr, dg, db; /* linear r,g,b scaled to 0..1 */
+} Background;
+
+/* Basic image formats; control the data but not the layout thereof. */
+#define BASE_FORMATS\
+   (PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_LINEAR)
+
+/* Read a Pixel from a buffer.  The code below stores the correct routine for
+ * the format in a function pointer, these are the routines:
+ */
+static void
+gp_g8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = p->g = p->b = pp[0];
+   p->a = 255;
+}
+
+static void
+gp_ga8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = p->g = p->b = pp[0];
+   p->a = pp[1];
+}
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+static void
+gp_ag8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = p->g = p->b = pp[1];
+   p->a = pp[0];
+}
+#endif
+
+static void
+gp_rgb8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[0];
+   p->g = pp[1];
+   p->b = pp[2];
+   p->a = 255;
+}
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+static void
+gp_bgr8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[2];
+   p->g = pp[1];
+   p->b = pp[0];
+   p->a = 255;
+}
+#endif
+
+static void
+gp_rgba8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[0];
+   p->g = pp[1];
+   p->b = pp[2];
+   p->a = pp[3];
+}
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+static void
+gp_bgra8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[2];
+   p->g = pp[1];
+   p->b = pp[0];
+   p->a = pp[3];
+}
+#endif
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+static void
+gp_argb8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[1];
+   p->g = pp[2];
+   p->b = pp[3];
+   p->a = pp[0];
+}
+#endif
+
+#if defined(PNG_FORMAT_AFIRST_SUPPORTED) && defined(PNG_FORMAT_BGR_SUPPORTED)
+static void
+gp_abgr8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[3];
+   p->g = pp[2];
+   p->b = pp[1];
+   p->a = pp[0];
+}
+#endif
+
+static void
+gp_g16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = p->g = p->b = pp[0];
+   p->a = 65535;
+}
+
+static void
+gp_ga16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = p->g = p->b = pp[0];
+   p->a = pp[1];
+}
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+static void
+gp_ag16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = p->g = p->b = pp[1];
+   p->a = pp[0];
+}
+#endif
+
+static void
+gp_rgb16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[0];
+   p->g = pp[1];
+   p->b = pp[2];
+   p->a = 65535;
+}
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+static void
+gp_bgr16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[2];
+   p->g = pp[1];
+   p->b = pp[0];
+   p->a = 65535;
+}
+#endif
+
+static void
+gp_rgba16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[0];
+   p->g = pp[1];
+   p->b = pp[2];
+   p->a = pp[3];
+}
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+static void
+gp_bgra16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[2];
+   p->g = pp[1];
+   p->b = pp[0];
+   p->a = pp[3];
+}
+#endif
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+static void
+gp_argb16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[1];
+   p->g = pp[2];
+   p->b = pp[3];
+   p->a = pp[0];
+}
+#endif
+
+#if defined(PNG_FORMAT_AFIRST_SUPPORTED) && defined(PNG_FORMAT_BGR_SUPPORTED)
+static void
+gp_abgr16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[3];
+   p->g = pp[2];
+   p->b = pp[1];
+   p->a = pp[0];
+}
+#endif
+
+/* Given a format, return the correct one of the above functions. */
+static void (*
+get_pixel(png_uint_32 format))(Pixel *p, png_const_voidp pb)
+{
+   /* The color-map flag is irrelevant here - the caller of the function
+    * returned must either pass the buffer or, for a color-mapped image, the
+    * correct entry in the color-map.
+    */
+   if (format & PNG_FORMAT_FLAG_LINEAR)
+   {
+      if (format & PNG_FORMAT_FLAG_COLOR)
+      {
+#        ifdef PNG_FORMAT_BGR_SUPPORTED
+            if (format & PNG_FORMAT_FLAG_BGR)
+            {
+               if (format & PNG_FORMAT_FLAG_ALPHA)
+               {
+#                 ifdef PNG_FORMAT_AFIRST_SUPPORTED
+                     if (format & PNG_FORMAT_FLAG_AFIRST)
+                        return gp_abgr16;
+
+                     else
+#                 endif
+                     return gp_bgra16;
+               }
+
+               else
+                  return gp_bgr16;
+            }
+
+            else
+#        endif
+         {
+            if (format & PNG_FORMAT_FLAG_ALPHA)
+            {
+#              ifdef PNG_FORMAT_AFIRST_SUPPORTED
+                  if (format & PNG_FORMAT_FLAG_AFIRST)
+                     return gp_argb16;
+
+                  else
+#              endif
+                  return gp_rgba16;
+            }
+
+            else
+               return gp_rgb16;
+         }
+      }
+
+      else
+      {
+         if (format & PNG_FORMAT_FLAG_ALPHA)
+         {
+#           ifdef PNG_FORMAT_AFIRST_SUPPORTED
+               if (format & PNG_FORMAT_FLAG_AFIRST)
+                  return gp_ag16;
+
+               else
+#           endif
+               return gp_ga16;
+         }
+
+         else
+            return gp_g16;
+      }
+   }
+
+   else
+   {
+      if (format & PNG_FORMAT_FLAG_COLOR)
+      {
+#        ifdef PNG_FORMAT_BGR_SUPPORTED
+            if (format & PNG_FORMAT_FLAG_BGR)
+            {
+               if (format & PNG_FORMAT_FLAG_ALPHA)
+               {
+#                 ifdef PNG_FORMAT_AFIRST_SUPPORTED
+                     if (format & PNG_FORMAT_FLAG_AFIRST)
+                        return gp_abgr8;
+
+                     else
+#                 endif
+                     return gp_bgra8;
+               }
+
+               else
+                  return gp_bgr8;
+            }
+
+            else
+#        endif
+         {
+            if (format & PNG_FORMAT_FLAG_ALPHA)
+            {
+#              ifdef PNG_FORMAT_AFIRST_SUPPORTED
+                  if (format & PNG_FORMAT_FLAG_AFIRST)
+                     return gp_argb8;
+
+                  else
+#              endif
+                  return gp_rgba8;
+            }
+
+            else
+               return gp_rgb8;
+         }
+      }
+
+      else
+      {
+         if (format & PNG_FORMAT_FLAG_ALPHA)
+         {
+#           ifdef PNG_FORMAT_AFIRST_SUPPORTED
+               if (format & PNG_FORMAT_FLAG_AFIRST)
+                  return gp_ag8;
+
+               else
+#           endif
+               return gp_ga8;
+         }
+
+         else
+            return gp_g8;
+      }
+   }
+}
+
+/* Conversion between pixel formats.  The code above effectively eliminates the
+ * component ordering changes leaving three basic changes:
+ *
+ * 1) Remove an alpha channel by pre-multiplication or compositing on a
+ *    background color.  (Adding an alpha channel is a no-op.)
+ *
+ * 2) Remove color by mapping to grayscale.  (Grayscale to color is a no-op.)
+ *
+ * 3) Convert between 8-bit and 16-bit components.  (Both directtions are
+ *    relevant.)
+ *
+ * This gives the following base format conversion matrix:
+ *
+ *   OUT:    ----- 8-bit -----    ----- 16-bit -----
+ *   IN     G    GA   RGB  RGBA  G    GA   RGB  RGBA
+ *  8 G     .    .    .    .     lin  lin  lin  lin
+ *  8 GA    bckg .    bckc .     pre' pre  pre' pre
+ *  8 RGB   g8   g8   .    .     glin glin lin  lin
+ *  8 RGBA  g8b  g8   bckc .     gpr' gpre pre' pre
+ * 16 G     sRGB sRGB sRGB sRGB  .    .    .    .
+ * 16 GA    b16g unpg b16c unpc  A    .    A    .
+ * 16 RGB   sG   sG   sRGB sRGB  g16  g16  .    .
+ * 16 RGBA  gb16 sGp  cb16 sCp   g16  g16' A    .
+ *
+ *  8-bit to 8-bit:
+ * bckg: composite on gray background
+ * bckc: composite on color background
+ * g8:   convert sRGB components to sRGB grayscale
+ * g8b:  convert sRGB components to grayscale and composite on gray background
+ *
+ *  8-bit to 16-bit:
+ * lin:  make sRGB components linear, alpha := 65535
+ * pre:  make sRGB components linear and premultiply by alpha  (scale alpha)
+ * pre': as 'pre' but alpha := 65535
+ * glin: make sRGB components linear, convert to grayscale, alpha := 65535
+ * gpre: make sRGB components grayscale and linear and premultiply by alpha
+ * gpr': as 'gpre' but alpha := 65535
+ *
+ *  16-bit to 8-bit:
+ * sRGB: convert linear components to sRGB, alpha := 255
+ * unpg: unpremultiply gray component and convert to sRGB (scale alpha)
+ * unpc: unpremultiply color components and convert to sRGB (scale alpha)
+ * b16g: composite linear onto gray background and convert the result to sRGB
+ * b16c: composite linear onto color background and convert the result to sRGB
+ * sG:   convert linear RGB to sRGB grayscale
+ * sGp:  unpremultiply RGB then convert to sRGB grayscale
+ * sCp:  unpremultiply RGB then convert to sRGB
+ * gb16: composite linear onto background and convert to sRGB grayscale
+ *       (order doesn't matter, the composite and grayscale operations permute)
+ * cb16: composite linear onto background and convert to sRGB
+ *
+ *  16-bit to 16-bit:
+ * A:    set alpha to 65535
+ * g16:  convert linear RGB to linear grayscale (alpha := 65535)
+ * g16': as 'g16' but alpha is unchanged
+ */
+/* Simple copy: */
+static void
+gpc_noop(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   out->r = in->r;
+   out->g = in->g;
+   out->b = in->b;
+   out->a = in->a;
+}
+
+#if ALLOW_UNUSED_GPC
+static void
+gpc_nop8(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   if (in->a == 0)
+      out->r = out->g = out->b = 255;
+
+   else
+   {
+      out->r = in->r;
+      out->g = in->g;
+      out->b = in->b;
+   }
+
+   out->a = in->a;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+static void
+gpc_nop6(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   if (in->a == 0)
+      out->r = out->g = out->b = 65535;
+
+   else
+   {
+      out->r = in->r;
+      out->g = in->g;
+      out->b = in->b;
+   }
+
+   out->a = in->a;
+}
+#endif
+
+/* 8-bit to 8-bit conversions */
+/* bckg: composite on gray background */
+static void
+gpc_bckg(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+      out->r = out->g = out->b = back->ig;
+
+   else if (in->a >= 255)
+      out->r = out->g = out->b = in->g;
+
+   else
+   {
+      double a = in->a / 255.;
+
+      out->r = out->g = out->b = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a));
+   }
+
+   out->a = 255;
+}
+
+/* bckc: composite on color background */
+static void
+gpc_bckc(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+   {
+      out->r = back->ir;
+      out->g = back->ig;
+      out->b = back->ib;
+   }
+
+   else if (in->a >= 255)
+   {
+      out->r = in->r;
+      out->g = in->g;
+      out->b = in->b;
+   }
+
+   else
+   {
+      double a = in->a / 255.;
+
+      out->r = sRGB(sRGB_to_d[in->r] * a + back->dr * (1-a));
+      out->g = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a));
+      out->b = sRGB(sRGB_to_d[in->b] * a + back->db * (1-a));
+   }
+
+   out->a = 255;
+}
+
+/* g8: convert sRGB components to sRGB grayscale */
+static void
+gpc_g8(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = in->g;
+
+   else
+      out->r = out->g = out->b =
+         sRGB(YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+
+   out->a = in->a;
+}
+
+/* g8b: convert sRGB components to grayscale and composite on gray background */
+static void
+gpc_g8b(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+      out->r = out->g = out->b = back->ig;
+
+   else if (in->a >= 255)
+   {
+      if (in->r == in->g && in->g == in->b)
+         out->r = out->g = out->b = in->g;
+
+      else
+         out->r = out->g = out->b = sRGB(YfromRGB(
+            sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+   }
+
+   else
+   {
+      double a = in->a/255.;
+
+      out->r = out->g = out->b = sRGB(a * YfromRGB(sRGB_to_d[in->r],
+         sRGB_to_d[in->g], sRGB_to_d[in->b]) + back->dg * (1-a));
+   }
+
+   out->a = 255;
+}
+
+/* 8-bit to 16-bit conversions */
+/* lin: make sRGB components linear, alpha := 65535 */
+static void
+gpc_lin(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilinear(in->r);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilinear(in->b);
+   }
+
+   else
+   {
+      out->g = ilinear(in->g);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilinear(in->b);
+   }
+
+   out->a = 65535;
+}
+
+/* pre: make sRGB components linear and premultiply by alpha (scale alpha) */
+static void
+gpc_pre(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilineara(in->r, in->a);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilineara(in->b, in->a);
+   }
+
+   else
+   {
+      out->g = ilineara(in->g, in->a);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilineara(in->b, in->a);
+   }
+
+   out->a = in->a * 257;
+}
+
+/* pre': as 'pre' but alpha := 65535 */
+static void
+gpc_preq(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilineara(in->r, in->a);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilineara(in->b, in->a);
+   }
+
+   else
+   {
+      out->g = ilineara(in->g, in->a);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilineara(in->b, in->a);
+   }
+
+   out->a = 65535;
+}
+
+/* glin: make sRGB components linear, convert to grayscale, alpha := 65535 */
+static void
+gpc_glin(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilinear(in->g);
+
+   else
+      out->r = out->g = out->b = u16d(65535 *
+         YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+
+   out->a = 65535;
+}
+
+/* gpre: make sRGB components grayscale and linear and premultiply by alpha */
+static void
+gpc_gpre(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilineara(in->g, in->a);
+
+   else
+      out->r = out->g = out->b = u16d(in->a * 257 *
+         YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+
+   out->a = 257 * in->a;
+}
+
+/* gpr': as 'gpre' but alpha := 65535 */
+static void
+gpc_gprq(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilineara(in->g, in->a);
+
+   else
+      out->r = out->g = out->b = u16d(in->a * 257 *
+         YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+
+   out->a = 65535;
+}
+
+/* 8-bit to 16-bit conversions for gAMA 45455 encoded values */
+/* Lin: make gAMA 45455 components linear, alpha := 65535 */
+static void
+gpc_Lin(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilinear_g22(in->r);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilinear_g22(in->b);
+   }
+
+   else
+   {
+      out->g = ilinear_g22(in->g);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilinear_g22(in->b);
+   }
+
+   out->a = 65535;
+}
+
+#if ALLOW_UNUSED_GPC
+/* Pre: make gAMA 45455 components linear and premultiply by alpha (scale alpha)
+ */
+static void
+gpc_Pre(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilineara_g22(in->r, in->a);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilineara_g22(in->b, in->a);
+   }
+
+   else
+   {
+      out->g = ilineara_g22(in->g, in->a);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilineara_g22(in->b, in->a);
+   }
+
+   out->a = in->a * 257;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+/* Pre': as 'Pre' but alpha := 65535 */
+static void
+gpc_Preq(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilineara_g22(in->r, in->a);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilineara_g22(in->b, in->a);
+   }
+
+   else
+   {
+      out->g = ilineara_g22(in->g, in->a);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilineara_g22(in->b, in->a);
+   }
+
+   out->a = 65535;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+/* Glin: make gAMA 45455 components linear, convert to grayscale, alpha := 65535
+ */
+static void
+gpc_Glin(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilinear_g22(in->g);
+
+   else
+      out->r = out->g = out->b = u16d(65535 *
+         YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
+
+   out->a = 65535;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+/* Gpre: make gAMA 45455 components grayscale and linear and premultiply by
+ * alpha.
+ */
+static void
+gpc_Gpre(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilineara_g22(in->g, in->a);
+
+   else
+      out->r = out->g = out->b = u16d(in->a * 257 *
+         YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
+
+   out->a = 257 * in->a;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+/* Gpr': as 'Gpre' but alpha := 65535 */
+static void
+gpc_Gprq(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilineara_g22(in->g, in->a);
+
+   else
+      out->r = out->g = out->b = u16d(in->a * 257 *
+         YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
+
+   out->a = 65535;
+}
+#endif
+
+/* 16-bit to 8-bit conversions */
+/* sRGB: convert linear components to sRGB, alpha := 255 */
+static void
+gpc_sRGB(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = isRGB(in->r);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = isRGB(in->b);
+   }
+
+   else
+   {
+      out->g = isRGB(in->g);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = isRGB(in->b);
+   }
+
+   out->a = 255;
+}
+
+/* unpg: unpremultiply gray component and convert to sRGB (scale alpha) */
+static void
+gpc_unpg(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->a <= 128)
+   {
+      out->r = out->g = out->b = 255;
+      out->a = 0;
+   }
+
+   else
+   {
+      out->r = out->g = out->b = sRGB((double)in->g / in->a);
+      out->a = u8d(in->a / 257.);
+   }
+}
+
+/* unpc: unpremultiply color components and convert to sRGB (scale alpha) */
+static void
+gpc_unpc(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->a <= 128)
+   {
+      out->r = out->g = out->b = 255;
+      out->a = 0;
+   }
+
+   else
+   {
+      out->r = sRGB((double)in->r / in->a);
+      out->g = sRGB((double)in->g / in->a);
+      out->b = sRGB((double)in->b / in->a);
+      out->a = u8d(in->a / 257.);
+   }
+}
+
+/* b16g: composite linear onto gray background and convert the result to sRGB */
+static void
+gpc_b16g(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+      out->r = out->g = out->b = back->ig;
+
+   else
+   {
+      double a = in->a/65535.;
+      double a1 = 1-a;
+
+      a /= 65535;
+      out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1);
+   }
+
+   out->a = 255;
+}
+
+/* b16c: composite linear onto color background and convert the result to sRGB*/
+static void
+gpc_b16c(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+   {
+      out->r = back->ir;
+      out->g = back->ig;
+      out->b = back->ib;
+   }
+
+   else
+   {
+      double a = in->a/65535.;
+      double a1 = 1-a;
+
+      a /= 65535;
+      out->r = sRGB(in->r * a + back->dr * a1);
+      out->g = sRGB(in->g * a + back->dg * a1);
+      out->b = sRGB(in->b * a + back->db * a1);
+   }
+
+   out->a = 255;
+}
+
+/* sG: convert linear RGB to sRGB grayscale */
+static void
+gpc_sG(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/65535);
+   out->a = 255;
+}
+
+/* sGp: unpremultiply RGB then convert to sRGB grayscale */
+static void
+gpc_sGp(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->a <= 128)
+   {
+      out->r = out->g = out->b = 255;
+      out->a = 0;
+   }
+
+   else
+   {
+      out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/in->a);
+      out->a = u8d(in->a / 257.);
+   }
+}
+
+/* sCp: unpremultiply RGB then convert to sRGB */
+static void
+gpc_sCp(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->a <= 128)
+   {
+      out->r = out->g = out->b = 255;
+      out->a = 0;
+   }
+
+   else
+   {
+      out->r = sRGB((double)in->r / in->a);
+      out->g = sRGB((double)in->g / in->a);
+      out->b = sRGB((double)in->b / in->a);
+      out->a = u8d(in->a / 257.);
+   }
+}
+
+/* gb16: composite linear onto background and convert to sRGB grayscale */
+/*  (order doesn't matter, the composite and grayscale operations permute) */
+static void
+gpc_gb16(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+      out->r = out->g = out->b = back->ig;
+
+   else if (in->a >= 65535)
+      out->r = out->g = out->b = isRGB(in->g);
+
+   else
+   {
+      double a = in->a / 65535.;
+      double a1 = 1-a;
+
+      a /= 65535;
+      out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1);
+   }
+
+   out->a = 255;
+}
+
+/* cb16: composite linear onto background and convert to sRGB */
+static void
+gpc_cb16(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+   {
+      out->r = back->ir;
+      out->g = back->ig;
+      out->b = back->ib;
+   }
+
+   else if (in->a >= 65535)
+   {
+      out->r = isRGB(in->r);
+      out->g = isRGB(in->g);
+      out->b = isRGB(in->b);
+   }
+
+   else
+   {
+      double a = in->a / 65535.;
+      double a1 = 1-a;
+
+      a /= 65535;
+      out->r = sRGB(in->r * a + back->dr * a1);
+      out->g = sRGB(in->g * a + back->dg * a1);
+      out->b = sRGB(in->b * a + back->db * a1);
+   }
+
+   out->a = 255;
+}
+
+/* 16-bit to 16-bit conversions */
+/* A:    set alpha to 65535 */
+static void
+gpc_A(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   out->r = in->r;
+   out->g = in->g;
+   out->b = in->b;
+   out->a = 65535;
+}
+
+/* g16:  convert linear RGB to linear grayscale (alpha := 65535) */
+static void
+gpc_g16(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b));
+   out->a = 65535;
+}
+
+/* g16': as 'g16' but alpha is unchanged */
+static void
+gpc_g16q(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b));
+   out->a = in->a;
+}
+
+#if ALLOW_UNUSED_GPC
+/* Unused functions (to hide them from GCC unused function warnings) */
+void (* const gpc_unused[])
+   (Pixel *out, const Pixel *in, const Background *back) =
+{
+   gpc_Pre, gpc_Preq, gpc_Glin, gpc_Gpre, gpc_Gprq, gpc_nop8, gpc_nop6
+};
+#endif
+
+/*   OUT:    ----- 8-bit -----    ----- 16-bit -----
+ *   IN     G    GA   RGB  RGBA  G    GA   RGB  RGBA
+ *  8 G     .    .    .    .     lin  lin  lin  lin
+ *  8 GA    bckg .    bckc .     pre' pre  pre' pre
+ *  8 RGB   g8   g8   .    .     glin glin lin  lin
+ *  8 RGBA  g8b  g8   bckc .     gpr' gpre pre' pre
+ * 16 G     sRGB sRGB sRGB sRGB  .    .    .    .
+ * 16 GA    b16g unpg b16c unpc  A    .    A    .
+ * 16 RGB   sG   sG   sRGB sRGB  g16  g16  .    .
+ * 16 RGBA  gb16 sGp  cb16 sCp   g16  g16' A    .
+ *
+ * The matrix is held in an array indexed thus:
+ *
+ *   gpc_fn[out_format & BASE_FORMATS][in_format & BASE_FORMATS];
+ */
+/* This will produce a compile time error if the FORMAT_FLAG values don't
+ * match the above matrix!
+ */
+#if PNG_FORMAT_FLAG_ALPHA == 1 && PNG_FORMAT_FLAG_COLOR == 2 &&\
+   PNG_FORMAT_FLAG_LINEAR == 4
+static void (* const gpc_fn[8/*in*/][8/*out*/])
+   (Pixel *out, const Pixel *in, const Background *back) =
+{
+/*out: G-8     GA-8     RGB-8    RGBA-8    G-16     GA-16   RGB-16  RGBA-16 */
+   {gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_Lin, gpc_Lin, gpc_Lin, gpc_Lin },
+   {gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre },
+   {gpc_g8,  gpc_g8,  gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin },
+   {gpc_g8b, gpc_g8,  gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre },
+   {gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop},
+   {gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A,   gpc_noop,gpc_A,   gpc_noop},
+   {gpc_sG,  gpc_sG,  gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop},
+   {gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp,  gpc_g16, gpc_g16q,gpc_A,   gpc_noop}
+};
+
+/* The array is repeated for the cases where both the input and output are color
+ * mapped because then different algorithms are used.
+ */
+static void (* const gpc_fn_colormapped[8/*in*/][8/*out*/])
+   (Pixel *out, const Pixel *in, const Background *back) =
+{
+/*out: G-8     GA-8     RGB-8    RGBA-8    G-16     GA-16   RGB-16  RGBA-16 */
+   {gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_lin, gpc_lin, gpc_lin, gpc_lin },
+   {gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre },
+   {gpc_g8,  gpc_g8,  gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin },
+   {gpc_g8b, gpc_g8,  gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre },
+   {gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop},
+   {gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A,   gpc_noop,gpc_A,   gpc_noop},
+   {gpc_sG,  gpc_sG,  gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop},
+   {gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp,  gpc_g16, gpc_g16q,gpc_A,   gpc_noop}
+};
+
+/* The error arrays record the error in the same matrix; 64 entries, however
+ * the different algorithms used in libpng for colormap and direct conversions
+ * mean that four separate matrices are used (for each combination of
+ * colormapped and direct.)
+ *
+ * In some cases the conversion between sRGB formats goes via a linear
+ * intermediate; an sRGB to linear conversion (as above) is followed by a simple
+ * linear to sRGB step with no other conversions.  This is done by a separate
+ * error array from an arbitrary 'in' format to one of the four basic outputs
+ * (since final output is always sRGB not colormapped).
+ *
+ * These arrays may be modified if the --accumulate flag is set during the run;
+ * then instead of logging errors they are simply added in.
+ *
+ * The three entries are currently for transparent, partially transparent and
+ * opaque input pixel values.  Notice that alpha should be exact in each case.
+ *
+ * Errors in alpha should only occur when converting from a direct format
+ * to a colormapped format, when alpha is effectively smashed (so large
+ * errors can occur.)  There should be no error in the '0' and 'opaque'
+ * values.  The fourth entry in the array is used for the alpha error (and it
+ * should always be zero for the 'via linear' case since this is never color
+ * mapped.)
+ *
+ * Mapping to a colormap smashes the colors, it is necessary to have separate
+ * values for these cases because they are much larger; it is very much
+ * impossible to obtain a reasonable result, these are held in
+ * gpc_error_to_colormap.
+ */
+#if PNG_FORMAT_FLAG_COLORMAP == 8 /* extra check also required */
+#  include "pngstest-errors.h" /* machine generated */
+#endif /* COLORMAP flag check */
+#endif /* flag checks */
+
+typedef struct
+{
+   /* Basic pixel information: */
+   Image*       in_image;   /* Input image */
+   const Image* out_image;  /* Output image */
+
+   /* 'background' is the value passed to the gpc_ routines, it may be NULL if
+    * it should not be used (*this* program has an error if it crashes as a
+    * result!)
+    */
+   Background        background_color;
+   const Background* background;
+
+   /* Precalculated values: */
+   int          in_opaque;   /* Value of input alpha that is opaque */
+   int          is_palette;  /* Sample values come from the palette */
+   int          accumulate;  /* Accumulate component errors (don't log) */
+   int          output_8bit; /* Output is 8-bit (else 16-bit) */
+
+   void (*in_gp)(Pixel*, png_const_voidp);
+   void (*out_gp)(Pixel*, png_const_voidp);
+
+   void (*transform)(Pixel *out, const Pixel *in, const Background *back);
+      /* A function to perform the required transform */
+
+   void (*from_linear)(Pixel *out, const Pixel *in, const Background *back);
+      /* For 'via_linear' transforms the final, from linear, step, else NULL */
+
+   png_uint_16 error[4];
+      /* Three error values for transparent, partially transparent and opaque
+       * input pixels (in turn).
+       */
+
+   png_uint_16 *error_ptr;
+      /* Where these are stored in the static array (for 'accumulate') */
+}
+Transform;
+
+/* Return a 'transform' as above for the given format conversion. */
+static void
+transform_from_formats(Transform *result, Image *in_image,
+   const Image *out_image, png_const_colorp background, int via_linear)
+{
+   png_uint_32 in_format, out_format;
+   png_uint_32 in_base, out_base;
+
+   memset(result, 0, sizeof *result);
+
+   /* Store the original images for error messages */
+   result->in_image = in_image;
+   result->out_image = out_image;
+
+   in_format = in_image->image.format;
+   out_format = out_image->image.format;
+
+   if (in_format & PNG_FORMAT_FLAG_LINEAR)
+      result->in_opaque = 65535;
+   else
+      result->in_opaque = 255;
+
+   result->output_8bit = (out_format & PNG_FORMAT_FLAG_LINEAR) == 0;
+
+   result->is_palette = 0; /* set by caller if required */
+   result->accumulate = (in_image->opts & ACCUMULATE) != 0;
+
+   /* The loaders (which need the ordering information) */
+   result->in_gp = get_pixel(in_format);
+   result->out_gp = get_pixel(out_format);
+
+   /* Remove the ordering information: */
+   in_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP;
+   in_base = in_format & BASE_FORMATS;
+   out_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP;
+   out_base = out_format & BASE_FORMATS;
+
+   if (via_linear)
+   {
+      /* Check for an error in this program: */
+      if (out_format & (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLORMAP))
+      {
+         fprintf(stderr, "internal transform via linear error 0x%x->0x%x\n",
+            in_format, out_format);
+         exit(1);
+      }
+
+      result->transform = gpc_fn[in_base][out_base | PNG_FORMAT_FLAG_LINEAR];
+      result->from_linear = gpc_fn[out_base | PNG_FORMAT_FLAG_LINEAR][out_base];
+      result->error_ptr = gpc_error_via_linear[in_format][out_format];
+   }
+
+   else if (~in_format & out_format & PNG_FORMAT_FLAG_COLORMAP)
+   {
+      /* The input is not colormapped but the output is, the errors will
+       * typically be large (only the grayscale-no-alpha case permits preserving
+       * even 8-bit values.)
+       */
+      result->transform = gpc_fn[in_base][out_base];
+      result->from_linear = NULL;
+      result->error_ptr = gpc_error_to_colormap[in_base][out_base];
+   }
+
+   else
+   {
+      /* The caller handles the colormap->pixel value conversion, so the
+       * transform function just gets a pixel value, however because libpng
+       * currently contains a different implementation for mapping a colormap if
+       * both input and output are colormapped we need different conversion
+       * functions to deal with errors in the libpng implementation.
+       */
+      if (in_format & out_format & PNG_FORMAT_FLAG_COLORMAP)
+         result->transform = gpc_fn_colormapped[in_base][out_base];
+      else
+         result->transform = gpc_fn[in_base][out_base];
+      result->from_linear = NULL;
+      result->error_ptr = gpc_error[in_format][out_format];
+   }
+
+   /* Follow the libpng simplified API rules to work out what to pass to the gpc
+    * routines as a background value, if one is not required pass NULL so that
+    * this program crashes in the even of a programming error.
+    */
+   result->background = NULL; /* default: not required */
+
+   /* Rule 1: background only need be supplied if alpha is to be removed */
+   if (in_format & ~out_format & PNG_FORMAT_FLAG_ALPHA)
+   {
+      /* The input value is 'NULL' to use the background and (otherwise) an sRGB
+       * background color (to use a solid color).  The code above uses a fixed
+       * byte value, BUFFER_INIT8, for buffer even for 16-bit output.  For
+       * linear (16-bit) output the sRGB background color is ignored; the
+       * composition is always on the background (so BUFFER_INIT8 * 257), except
+       * that for the colormap (i.e. linear colormapped output) black is used.
+       */
+      result->background = &result->background_color;
+
+      if (out_format & PNG_FORMAT_FLAG_LINEAR || via_linear)
+      {
+         if (out_format & PNG_FORMAT_FLAG_COLORMAP)
+         {
+            result->background_color.ir =
+               result->background_color.ig =
+               result->background_color.ib = 0;
+            result->background_color.dr =
+               result->background_color.dg =
+               result->background_color.db = 0;
+         }
+
+         else
+         {
+            result->background_color.ir =
+               result->background_color.ig =
+               result->background_color.ib = BUFFER_INIT8 * 257;
+            result->background_color.dr =
+               result->background_color.dg =
+               result->background_color.db = 0;
+         }
+      }
+
+      else /* sRGB output */
+      {
+         if (background != NULL)
+         {
+            if (out_format & PNG_FORMAT_FLAG_COLOR)
+            {
+               result->background_color.ir = background->red;
+               result->background_color.ig = background->green;
+               result->background_color.ib = background->blue;
+               /* TODO: sometimes libpng uses the power law conversion here, how
+                * to handle this?
+                */
+               result->background_color.dr = sRGB_to_d[background->red];
+               result->background_color.dg = sRGB_to_d[background->green];
+               result->background_color.db = sRGB_to_d[background->blue];
+            }
+
+            else /* grayscale: libpng only looks at 'g' */
+            {
+               result->background_color.ir =
+                  result->background_color.ig =
+                  result->background_color.ib = background->green;
+               /* TODO: sometimes libpng uses the power law conversion here, how
+                * to handle this?
+                */
+               result->background_color.dr =
+                  result->background_color.dg =
+                  result->background_color.db = sRGB_to_d[background->green];
+            }
+         }
+
+         else if ((out_format & PNG_FORMAT_FLAG_COLORMAP) == 0)
+         {
+            result->background_color.ir =
+               result->background_color.ig =
+               result->background_color.ib = BUFFER_INIT8;
+            /* TODO: sometimes libpng uses the power law conversion here, how
+             * to handle this?
+             */
+            result->background_color.dr =
+               result->background_color.dg =
+               result->background_color.db = sRGB_to_d[BUFFER_INIT8];
+         }
+
+         /* Else the output is colormapped and a background color must be
+          * provided; if pngstest crashes then that is a bug in this program
+          * (though libpng should png_error as well.)
+          */
+         else
+            result->background = NULL;
+      }
+   }
+
+   if (result->background == NULL)
+   {
+      result->background_color.ir =
+         result->background_color.ig =
+         result->background_color.ib = -1; /* not used */
+      result->background_color.dr =
+         result->background_color.dg =
+         result->background_color.db = 1E30; /* not used */
+   }
+
+
+   /* Copy the error values into the Transform: */
+   result->error[0] = result->error_ptr[0];
+   result->error[1] = result->error_ptr[1];
+   result->error[2] = result->error_ptr[2];
+   result->error[3] = result->error_ptr[3];
+}
+
+
+/* Compare two pixels.
+ *
+ * OLD error values:
+static int error_to_linear = 811; * by experiment *
+static int error_to_linear_grayscale = 424; * by experiment *
+static int error_to_sRGB = 6; * by experiment *
+static int error_to_sRGB_grayscale = 17; * libpng error by calculation +
+                                            2 by experiment *
+static int error_in_compose = 2; * by experiment *
+static int error_in_premultiply = 1;
+ *
+ * The following is *just* the result of a round trip from 8-bit sRGB to linear
+ * then back to 8-bit sRGB when it is done by libpng.  There are two problems:
+ *
+ * 1) libpng currently uses a 2.2 power law with no linear segment, this results
+ * in instability in the low values and even with 16-bit precision sRGB(1) ends
+ * up mapping to sRGB(0) as a result of rounding in the 16-bit representation.
+ * This gives an error of 1 in the handling of value 1 only.
+ *
+ * 2) libpng currently uses an intermediate 8-bit linear value in gamma
+ * correction of 8-bit values.  This results in many more errors, the worse of
+ * which is mapping sRGB(14) to sRGB(0).
+ *
+ * The general 'error_via_linear' is more complex because of pre-multiplication,
+ * this compounds the 8-bit errors according to the alpha value of the pixel.
+ * As a result 256 values are pre-calculated for error_via_linear.
+ */
+#if 0
+static int error_in_libpng_gamma;
+static int error_via_linear[256]; /* Indexed by 8-bit alpha */
+
+static void
+init_error_via_linear(void)
+{
+   int alpha;
+
+   error_via_linear[0] = 255; /* transparent pixel */
+
+   for (alpha=1; alpha<=255; ++alpha)
+   {
+      /* 16-bit values less than 128.5 get rounded to 8-bit 0 and so the worst
+       * case error arises with 16-bit 128.5, work out what sRGB
+       * (non-associated) value generates 128.5; any value less than this is
+       * going to map to 0, so the worst error is floor(value).
+       *
+       * Note that errors are considerably higher (more than a factor of 2)
+       * because libpng uses a simple power law for sRGB data at present.
+       *
+       * Add .1 for arithmetic errors inside libpng.
+       */
+      double v = floor(255*pow(.5/*(128.5 * 255 / 65535)*/ / alpha, 1/2.2)+.1);
+
+      error_via_linear[alpha] = (int)v;
+   }
+
+   /* This is actually 14.99, but, despite the closeness to 15, 14 seems to work
+    * ok in this case.
+    */
+   error_in_libpng_gamma = 14;
+}
+#endif
+
+static void
+print_pixel(char string[64], const Pixel *pixel, png_uint_32 format)
+{
+   switch (format & (PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR))
+   {
+      case 0:
+         sprintf(string, "%s(%d)", format_names[format], pixel->g);
+         break;
+
+      case PNG_FORMAT_FLAG_ALPHA:
+         sprintf(string, "%s(%d,%d)", format_names[format], pixel->g,
+            pixel->a);
+         break;
+
+      case PNG_FORMAT_FLAG_COLOR:
+         sprintf(string, "%s(%d,%d,%d)", format_names[format],
+            pixel->r, pixel->g, pixel->b);
+         break;
+
+      case PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA:
+         sprintf(string, "%s(%d,%d,%d,%d)", format_names[format],
+            pixel->r, pixel->g, pixel->b, pixel->a);
+         break;
+
+      default:
+         sprintf(string, "invalid-format");
+         break;
+   }
+}
+
+static int
+logpixel(const Transform *transform, png_uint_32 x, png_uint_32 y,
+   const Pixel *in, const Pixel *calc, const Pixel *out, const char *reason)
+{
+   png_uint_32 in_format = transform->in_image->image.format;
+   png_uint_32 out_format = transform->out_image->image.format;
+
+   png_uint_32 back_format = out_format & ~PNG_FORMAT_FLAG_ALPHA;
+   const char *via_linear = "";
+
+   char pixel_in[64], pixel_calc[64], pixel_out[64], pixel_loc[64];
+   char background_info[100];
+
+   print_pixel(pixel_in, in, in_format);
+   print_pixel(pixel_calc, calc, out_format);
+   print_pixel(pixel_out, out, out_format);
+
+   if (transform->is_palette)
+      sprintf(pixel_loc, "palette: %lu", (unsigned long)y);
+   else
+      sprintf(pixel_loc, "%lu,%lu", (unsigned long)x, (unsigned long)y);
+
+   if (transform->from_linear != NULL)
+   {
+      via_linear = " (via linear)";
+      /* And as a result the *read* format which did any background processing
+       * was itself linear, so the background color information is also
+       * linear.
+       */
+      back_format |= PNG_FORMAT_FLAG_LINEAR;
+   }
+
+   if (transform->background != NULL)
+   {
+      Pixel back;
+      char pixel_back[64];
+
+      back.r = transform->background->ir;
+      back.g = transform->background->ig;
+      back.b = transform->background->ib;
+      back.a = -1; /* not used */
+
+      print_pixel(pixel_back, &back, back_format);
+      sprintf(background_info, " on background %s", pixel_back);
+   }
+
+   else
+      background_info[0] = 0;
+
+   if (transform->in_image->file_name != transform->out_image->file_name)
+   {
+      char error_buffer[512];
+      sprintf(error_buffer,
+         "(%s) %s error%s:\n %s%s ->\n       %s\n  not: %s.\n"
+         "Use --preserve and examine: ", pixel_loc, reason, via_linear,
+         pixel_in, background_info, pixel_out, pixel_calc);
+      return logerror(transform->in_image, transform->in_image->file_name,
+         error_buffer, transform->out_image->file_name);
+   }
+
+   else
+   {
+      char error_buffer[512];
+      sprintf(error_buffer,
+         "(%s) %s error%s:\n %s%s ->\n       %s\n  not: %s.\n"
+         " The error happened when reading the original file with this format.",
+         pixel_loc, reason, via_linear, pixel_in, background_info, pixel_out,
+         pixel_calc);
+      return logerror(transform->in_image, transform->in_image->file_name,
+         error_buffer, "");
+   }
+}
+
+static int
+cmppixel(Transform *transform, png_const_voidp in, png_const_voidp out,
+   png_uint_32 x, png_uint_32 y/*or palette index*/)
+{
+   int maxerr;
+   png_const_charp errmsg;
+   Pixel pixel_in, pixel_calc, pixel_out;
+
+   transform->in_gp(&pixel_in, in);
+
+   if (transform->from_linear == NULL)
+      transform->transform(&pixel_calc, &pixel_in, transform->background);
+
+   else
+   {
+      transform->transform(&pixel_out, &pixel_in, transform->background);
+      transform->from_linear(&pixel_calc, &pixel_out, NULL);
+   }
+
+   transform->out_gp(&pixel_out, out);
+
+   /* Eliminate the case where the input and output values match exactly. */
+   if (pixel_calc.a == pixel_out.a && pixel_calc.r == pixel_out.r &&
+      pixel_calc.g == pixel_out.g && pixel_calc.b == pixel_out.b)
+      return 1;
+
+   /* Eliminate the case where the output pixel is transparent and the output
+    * is 8-bit - any component values are valid.  Don't check the input alpha
+    * here to also skip the 16-bit small alpha cases.
+    */
+   if (transform->output_8bit && pixel_calc.a == 0 && pixel_out.a == 0)
+      return 1;
+
+   /* Check for alpha errors first; an alpha error can damage the components too
+    * so avoid spurious checks on components if one is found.
+    */
+   errmsg = NULL;
+   {
+      int err_a = abs(pixel_calc.a-pixel_out.a);
+
+      if (err_a > transform->error[3])
+      {
+         /* If accumulating check the components too */
+         if (transform->accumulate)
+            transform->error[3] = (png_uint_16)err_a;
+
+         else
+            errmsg = "alpha";
+      }
+   }
+
+   /* Now if *either* of the output alphas are 0 but alpha is within tolerance
+    * eliminate the 8-bit component comparison.
+    */
+   if (errmsg == NULL && transform->output_8bit &&
+      (pixel_calc.a == 0 || pixel_out.a == 0))
+      return 1;
+
+   if (errmsg == NULL) /* else just signal an alpha error */
+   {
+      int err_r = abs(pixel_calc.r - pixel_out.r);
+      int err_g = abs(pixel_calc.g - pixel_out.g);
+      int err_b = abs(pixel_calc.b - pixel_out.b);
+      int limit;
+
+      if ((err_r | err_g | err_b) == 0)
+         return 1; /* exact match */
+
+      /* Mismatch on a component, check the input alpha */
+      if (pixel_in.a >= transform->in_opaque)
+      {
+         errmsg = "opaque component";
+         limit = 2; /* opaque */
+      }
+
+      else if (pixel_in.a > 0)
+      {
+         errmsg = "alpha component";
+         limit = 1; /* partially transparent */
+      }
+
+      else
+      {
+         errmsg = "transparent component (background)";
+         limit = 0; /* transparent */
+      }
+
+      maxerr = err_r;
+      if (maxerr < err_g) maxerr = err_g;
+      if (maxerr < err_b) maxerr = err_b;
+
+      if (maxerr <= transform->error[limit])
+         return 1; /* within the error limits */
+
+      /* Handle a component mis-match; log it, just return an error code, or
+       * accumulate it.
+       */
+      if (transform->accumulate)
+      {
+         transform->error[limit] = (png_uint_16)maxerr;
+         return 1; /* to cause the caller to keep going */
+      }
+   }
+
+   /* Failure to match and not accumulating, so the error must be logged. */
+   return logpixel(transform, x, y, &pixel_in, &pixel_calc, &pixel_out, errmsg);
+}
+
+static png_byte
+component_loc(png_byte loc[4], png_uint_32 format)
+{
+   /* Given a format return the number of channels and the location of
+    * each channel.
+    *
+    * The mask 'loc' contains the component offset of the channels in the
+    * following order.  Note that if 'format' is grayscale the entries 1-3 must
+    * all contain the location of the gray channel.
+    *
+    * 0: alpha
+    * 1: red or gray
+    * 2: green or gray
+    * 3: blue or gray
+    */
+   png_byte channels;
+
+   if (format & PNG_FORMAT_FLAG_COLOR)
+   {
+      channels = 3;
+
+      loc[2] = 1;
+
+#     ifdef PNG_FORMAT_BGR_SUPPORTED
+         if (format & PNG_FORMAT_FLAG_BGR)
+         {
+            loc[1] = 2;
+            loc[3] = 0;
+         }
+
+         else
+#     endif
+      {
+         loc[1] = 0;
+         loc[3] = 2;
+      }
+   }
+
+   else
+   {
+      channels = 1;
+      loc[1] = loc[2] = loc[3] = 0;
+   }
+
+   if (format & PNG_FORMAT_FLAG_ALPHA)
+   {
+#     ifdef PNG_FORMAT_AFIRST_SUPPORTED
+         if (format & PNG_FORMAT_FLAG_AFIRST)
+         {
+            loc[0] = 0;
+            ++loc[1];
+            ++loc[2];
+            ++loc[3];
+         }
+
+         else
+#     endif
+         loc[0] = channels;
+
+      ++channels;
+   }
+
+   else
+      loc[0] = 4; /* not present */
+
+   return channels;
+}
+
+/* Compare two images, the original 'a', which was written out then read back in
+ * to * give image 'b'.  The formats may have been changed.
+ */
+static int
+compare_two_images(Image *a, Image *b, int via_linear,
+   png_const_colorp background)
+{
+   ptrdiff_t stridea = a->stride;
+   ptrdiff_t strideb = b->stride;
+   png_const_bytep rowa = a->buffer+16;
+   png_const_bytep rowb = b->buffer+16;
+   png_uint_32 width = a->image.width;
+   png_uint_32 height = a->image.height;
+   png_uint_32 formata = a->image.format;
+   png_uint_32 formatb = b->image.format;
+   unsigned int a_sample = PNG_IMAGE_SAMPLE_SIZE(formata);
+   unsigned int b_sample = PNG_IMAGE_SAMPLE_SIZE(formatb);
+   int alpha_added, alpha_removed;
+   int bchannels;
+   png_uint_32 y;
+   Transform tr;
+   int btoa[4]={0,0,0,0};
+
+   /* This should never happen: */
+   if (width != b->image.width || height != b->image.height)
+      return logerror(a, a->file_name, ": width x height changed: ",
+         b->file_name);
+
+   /* Set up the background and the transform */
+   transform_from_formats(&tr, a, b, background, via_linear);
+
+   /* Find the first row and inter-row space. */
+   if (!(formata & PNG_FORMAT_FLAG_COLORMAP) &&
+      (formata & PNG_FORMAT_FLAG_LINEAR))
+      stridea *= 2;
+
+   if (!(formatb & PNG_FORMAT_FLAG_COLORMAP) &&
+      (formatb & PNG_FORMAT_FLAG_LINEAR))
+      strideb *= 2;
+
+   if (stridea < 0) rowa += (height-1) * (-stridea);
+   if (strideb < 0) rowb += (height-1) * (-strideb);
+
+   /* First shortcut the two colormap case by comparing the image data; if it
+    * matches then we expect the colormaps to match, although this is not
+    * absolutely necessary for an image match.  If the colormaps fail to match
+    * then there is a problem in libpng.
+    */
+   if (formata & formatb & PNG_FORMAT_FLAG_COLORMAP)
+   {
+      /* Only check colormap entries that actually exist; */
+      png_const_bytep ppa, ppb;
+      int match;
+      png_byte in_use[256], amax = 0, bmax = 0;
+
+      memset(in_use, 0, sizeof in_use);
+
+      ppa = rowa;
+      ppb = rowb;
+
+      /* Do this the slow way to accumulate the 'in_use' flags, don't break out
+       * of the loop until the end; this validates the color-mapped data to
+       * ensure all pixels are valid color-map indexes.
+       */
+      for (y=0, match=1; y<height && match; ++y, ppa += stridea, ppb += strideb)
+      {
+         png_uint_32 x;
+
+         for (x=0; x<width; ++x)
+         {
+            png_byte bval = ppb[x];
+            png_byte aval = ppa[x];
+
+            if (bval > bmax)
+               bmax = bval;
+
+            if (bval != aval)
+               match = 0;
+
+            in_use[aval] = 1;
+            if (aval > amax)
+               amax = aval;
+         }
+      }
+
+      /* If the buffers match then the colormaps must too. */
+      if (match)
+      {
+         /* Do the color-maps match, entry by entry?  Only check the 'in_use'
+          * entries.  An error here should be logged as a color-map error.
+          */
+         png_const_bytep a_cmap = (png_const_bytep)a->colormap;
+         png_const_bytep b_cmap = (png_const_bytep)b->colormap;
+         int result = 1; /* match by default */
+
+         /* This is used in logpixel to get the error message correct. */
+         tr.is_palette = 1;
+
+         for (y=0; y<256; ++y, a_cmap += a_sample, b_cmap += b_sample)
+            if (in_use[y])
+         {
+            /* The colormap entries should be valid, but because libpng doesn't
+             * do any checking at present the original image may contain invalid
+             * pixel values.  These cause an error here (at present) unless
+             * accumulating errors in which case the program just ignores them.
+             */
+            if (y >= a->image.colormap_entries)
+            {
+               if ((a->opts & ACCUMULATE) == 0)
+               {
+                  char pindex[9];
+                  sprintf(pindex, "%lu[%lu]", (unsigned long)y,
+                     (unsigned long)a->image.colormap_entries);
+                  logerror(a, a->file_name, ": bad pixel index: ", pindex);
+               }
+               result = 0;
+            }
+
+            else if (y >= b->image.colormap_entries)
+            {
+               if ((b->opts & ACCUMULATE) == 0)
+                  {
+                  char pindex[9];
+                  sprintf(pindex, "%lu[%lu]", (unsigned long)y,
+                     (unsigned long)b->image.colormap_entries);
+                  logerror(b, b->file_name, ": bad pixel index: ", pindex);
+                  }
+               result = 0;
+            }
+
+            /* All the mismatches are logged here; there can only be 256! */
+            else if (!cmppixel(&tr, a_cmap, b_cmap, 0, y))
+               result = 0;
+         }
+
+         /* If requested, copy the error values back from the Transform. */
+         if (a->opts & ACCUMULATE)
+         {
+            tr.error_ptr[0] = tr.error[0];
+            tr.error_ptr[1] = tr.error[1];
+            tr.error_ptr[2] = tr.error[2];
+            tr.error_ptr[3] = tr.error[3];
+            result = 1; /* force a continue */
+         }
+
+         return result;
+      }
+
+      /* else the image buffers don't match pixel-wise so compare sample values
+       * instead, but first validate that the pixel indexes are in range (but
+       * only if not accumulating, when the error is ignored.)
+       */
+      else if ((a->opts & ACCUMULATE) == 0)
+      {
+#        ifdef __GNUC__
+#           define BYTE_CHARS 20 /* 2^32: GCC sprintf warning */
+#        else
+#           define BYTE_CHARS 3 /* 2^8: real maximum value */
+#        endif
+         /* Check the original image first,
+          * TODO: deal with input images with bad pixel values?
+          */
+         if (amax >= a->image.colormap_entries)
+         {
+            char pindex[3+2*BYTE_CHARS];
+            sprintf(pindex, "%d[%u]", amax,
+               (png_byte)/*SAFE*/a->image.colormap_entries);
+            return logerror(a, a->file_name, ": bad pixel index: ", pindex);
+         }
+
+         else if (bmax >= b->image.colormap_entries)
+         {
+            char pindex[3+2*BYTE_CHARS];
+            sprintf(pindex, "%d[%u]", bmax,
+               (png_byte)/*SAFE*/b->image.colormap_entries);
+            return logerror(b, b->file_name, ": bad pixel index: ", pindex);
+         }
+      }
+   }
+
+   /* We can directly compare pixel values without the need to use the read
+    * or transform support (i.e. a memory compare) if:
+    *
+    * 1) The bit depth has not changed.
+    * 2) RGB to grayscale has not been done (the reverse is ok; we just compare
+    *    the three RGB values to the original grayscale.)
+    * 3) An alpha channel has not been removed from an 8-bit format, or the
+    *    8-bit alpha value of the pixel was 255 (opaque).
+    *
+    * If an alpha channel has been *added* then it must have the relevant opaque
+    * value (255 or 65535).
+    *
+    * The fist two the tests (in the order given above) (using the boolean
+    * equivalence !a && !b == !(a || b))
+    */
+   if (!(((formata ^ formatb) & PNG_FORMAT_FLAG_LINEAR) |
+      (formata & (formatb ^ PNG_FORMAT_FLAG_COLOR) & PNG_FORMAT_FLAG_COLOR)))
+   {
+      /* Was an alpha channel changed? */
+      png_uint_32 alpha_changed = (formata ^ formatb) & PNG_FORMAT_FLAG_ALPHA;
+
+      /* Was an alpha channel removed?  (The third test.)  If so the direct
+       * comparison is only possible if the input alpha is opaque.
+       */
+      alpha_removed = (formata & alpha_changed) != 0;
+
+      /* Was an alpha channel added? */
+      alpha_added = (formatb & alpha_changed) != 0;
+
+      /* The channels may have been moved between input and output, this finds
+       * out how, recording the result in the btoa array, which says where in
+       * 'a' to find each channel of 'b'.  If alpha was added then btoa[alpha]
+       * ends up as 4 (and is not used.)
+       */
+      {
+         int i;
+         png_byte aloc[4];
+         png_byte bloc[4];
+
+         /* The following are used only if the formats match, except that
+          * 'bchannels' is a flag for matching formats.  btoa[x] says, for each
+          * channel in b, where to find the corresponding value in a, for the
+          * bchannels.  achannels may be different for a gray to rgb transform
+          * (a will be 1 or 2, b will be 3 or 4 channels.)
+          */
+         (void)component_loc(aloc, formata);
+         bchannels = component_loc(bloc, formatb);
+
+         /* Hence the btoa array. */
+         for (i=0; i<4; ++i) if (bloc[i] < 4)
+            btoa[bloc[i]] = aloc[i]; /* may be '4' for alpha */
+
+         if (alpha_added)
+            alpha_added = bloc[0]; /* location of alpha channel in image b */
+
+         else
+            alpha_added = 4; /* Won't match an image b channel */
+
+         if (alpha_removed)
+            alpha_removed = aloc[0]; /* location of alpha channel in image a */
+
+         else
+            alpha_removed = 4;
+      }
+   }
+
+   else
+   {
+      /* Direct compare is not possible, cancel out all the corresponding local
+       * variables.
+       */
+      bchannels = 0;
+      alpha_removed = alpha_added = 4;
+      btoa[3] = btoa[2] = btoa[1] = btoa[0] = 4; /* 4 == not present */
+   }
+
+   for (y=0; y<height; ++y, rowa += stridea, rowb += strideb)
+   {
+      png_const_bytep ppa, ppb;
+      png_uint_32 x;
+
+      for (x=0, ppa=rowa, ppb=rowb; x<width; ++x)
+      {
+         png_const_bytep psa, psb;
+
+         if (formata & PNG_FORMAT_FLAG_COLORMAP)
+            psa = (png_const_bytep)a->colormap + a_sample * *ppa++;
+         else
+            psa = ppa, ppa += a_sample;
+
+         if (formatb & PNG_FORMAT_FLAG_COLORMAP)
+            psb = (png_const_bytep)b->colormap + b_sample * *ppb++;
+         else
+            psb = ppb, ppb += b_sample;
+
+         /* Do the fast test if possible. */
+         if (bchannels)
+         {
+            /* Check each 'b' channel against either the corresponding 'a'
+             * channel or the opaque alpha value, as appropriate.  If
+             * alpha_removed value is set (not 4) then also do this only if the
+             * 'a' alpha channel (alpha_removed) is opaque; only relevant for
+             * the 8-bit case.
+             */
+            if (formatb & PNG_FORMAT_FLAG_LINEAR) /* 16-bit checks */
+            {
+               png_const_uint_16p pua = aligncastconst(png_const_uint_16p, psa);
+               png_const_uint_16p pub = aligncastconst(png_const_uint_16p, psb);
+
+               switch (bchannels)
+               {
+                  case 4:
+                     if (pua[btoa[3]] != pub[3]) break;
+                     /* FALLTHROUGH */
+                  case 3:
+                     if (pua[btoa[2]] != pub[2]) break;
+                     /* FALLTHROUGH */
+                  case 2:
+                     if (pua[btoa[1]] != pub[1]) break;
+                     /* FALLTHROUGH */
+                  case 1:
+                     if (pua[btoa[0]] != pub[0]) break;
+                     if (alpha_added != 4 && pub[alpha_added] != 65535) break;
+                     continue; /* x loop */
+                  default:
+                     break; /* impossible */
+               }
+            }
+
+            else if (alpha_removed == 4 || psa[alpha_removed] == 255)
+            {
+               switch (bchannels)
+               {
+                  case 4:
+                     if (psa[btoa[3]] != psb[3]) break;
+                     /* FALLTHROUGH */
+                  case 3:
+                     if (psa[btoa[2]] != psb[2]) break;
+                     /* FALLTHROUGH */
+                  case 2:
+                     if (psa[btoa[1]] != psb[1]) break;
+                     /* FALLTHROUGH */
+                  case 1:
+                     if (psa[btoa[0]] != psb[0]) break;
+                     if (alpha_added != 4 && psb[alpha_added] != 255) break;
+                     continue; /* x loop */
+                  default:
+                     break; /* impossible */
+               }
+            }
+         }
+
+         /* If we get to here the fast match failed; do the slow match for this
+          * pixel.
+          */
+         if (!cmppixel(&tr, psa, psb, x, y) && (a->opts & KEEP_GOING) == 0)
+            return 0; /* error case */
+      }
+   }
+
+   /* If requested, copy the error values back from the Transform. */
+   if (a->opts & ACCUMULATE)
+   {
+      tr.error_ptr[0] = tr.error[0];
+      tr.error_ptr[1] = tr.error[1];
+      tr.error_ptr[2] = tr.error[2];
+      tr.error_ptr[3] = tr.error[3];
+   }
+
+   return 1;
+}
+
+/* Read the file; how the read gets done depends on which of input_file and
+ * input_memory have been set.
+ */
+static int
+read_file(Image *image, png_uint_32 format, png_const_colorp background)
+{
+   memset(&image->image, 0, sizeof image->image);
+   image->image.version = PNG_IMAGE_VERSION;
+
+   if (image->input_memory != NULL)
+   {
+      if (!png_image_begin_read_from_memory(&image->image, image->input_memory,
+         image->input_memory_size))
+         return logerror(image, "memory init: ", image->file_name, "");
+   }
+
+#  ifdef PNG_STDIO_SUPPORTED
+      else if (image->input_file != NULL)
+      {
+         if (!png_image_begin_read_from_stdio(&image->image, image->input_file))
+            return logerror(image, "stdio init: ", image->file_name, "");
+      }
+
+      else
+      {
+         if (!png_image_begin_read_from_file(&image->image, image->file_name))
+            return logerror(image, "file init: ", image->file_name, "");
+      }
+#  else
+      else
+      {
+         return logerror(image, "unsupported file/stdio init: ",
+            image->file_name, "");
+      }
+#  endif
+
+   /* This must be set after the begin_read call: */
+   if (image->opts & sRGB_16BIT)
+      image->image.flags |= PNG_IMAGE_FLAG_16BIT_sRGB;
+
+   /* Have an initialized image with all the data we need plus, maybe, an
+    * allocated file (myfile) or buffer (mybuffer) that need to be freed.
+    */
+   {
+      int result;
+      png_uint_32 image_format;
+
+      /* Print both original and output formats. */
+      image_format = image->image.format;
+
+      if (image->opts & VERBOSE)
+      {
+         printf("%s %lu x %lu %s -> %s", image->file_name,
+            (unsigned long)image->image.width,
+            (unsigned long)image->image.height,
+            format_names[image_format & FORMAT_MASK],
+            (format & FORMAT_NO_CHANGE) != 0 || image->image.format == format
+            ? "no change" : format_names[format & FORMAT_MASK]);
+
+         if (background != NULL)
+            printf(" background(%d,%d,%d)\n", background->red,
+               background->green, background->blue);
+         else
+            printf("\n");
+
+         fflush(stdout);
+      }
+
+      /* 'NO_CHANGE' combined with the color-map flag forces the base format
+       * flags to be set on read to ensure that the original representation is
+       * not lost in the pass through a colormap format.
+       */
+      if ((format & FORMAT_NO_CHANGE) != 0)
+      {
+         if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 &&
+            (image_format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+            format = (image_format & ~BASE_FORMATS) | (format & BASE_FORMATS);
+
+         else
+            format = image_format;
+      }
+
+      image->image.format = format;
+
+      image->stride = PNG_IMAGE_ROW_STRIDE(image->image) + image->stride_extra;
+      allocbuffer(image);
+
+      result = png_image_finish_read(&image->image, background,
+         image->buffer+16, (png_int_32)image->stride, image->colormap);
+
+      checkbuffer(image, image->file_name);
+
+      if (result)
+         return checkopaque(image);
+
+      else
+         return logerror(image, image->file_name, ": image read failed", "");
+   }
+}
+
+/* Reads from a filename, which must be in image->file_name, but uses
+ * image->opts to choose the method.  The file is always read in its native
+ * format (the one the simplified API suggests).
+ */
+static int
+read_one_file(Image *image)
+{
+   if (!(image->opts & USE_FILE) || (image->opts & USE_STDIO))
+   {
+      /* memory or stdio. */
+      FILE *f = fopen(image->file_name, "rb");
+
+      if (f != NULL)
+      {
+         if (image->opts & USE_FILE)
+            image->input_file = f;
+
+         else /* memory */
+         {
+            if (fseek(f, 0, SEEK_END) == 0)
+            {
+               long int cb = ftell(f);
+
+               if (cb > 0)
+               {
+#ifndef __COVERITY__
+                  if ((unsigned long int)cb <= (size_t)~(size_t)0)
+#endif
+                  {
+                     png_bytep b = voidcast(png_bytep, malloc((size_t)cb));
+
+                     if (b != NULL)
+                     {
+                        rewind(f);
+
+                        if (fread(b, (size_t)cb, 1, f) == 1)
+                        {
+                           fclose(f);
+                           image->input_memory_size = cb;
+                           image->input_memory = b;
+                        }
+
+                        else
+                        {
+                           free(b);
+                           return logclose(image, f, image->file_name,
+                              ": read failed: ");
+                        }
+                     }
+
+                     else
+                        return logclose(image, f, image->file_name,
+                           ": out of memory: ");
+                  }
+
+                  else
+                     return logclose(image, f, image->file_name,
+                        ": file too big for this architecture: ");
+                     /* cb is the length of the file as a (long) and
+                      * this is greater than the maximum amount of
+                      * memory that can be requested from malloc.
+                      */
+               }
+
+               else if (cb == 0)
+                  return logclose(image, f, image->file_name,
+                     ": zero length: ");
+
+               else
+                  return logclose(image, f, image->file_name,
+                     ": tell failed: ");
+            }
+
+            else
+               return logclose(image, f, image->file_name, ": seek failed: ");
+         }
+      }
+
+      else
+         return logerror(image, image->file_name, ": open failed: ",
+            strerror(errno));
+   }
+
+   return read_file(image, FORMAT_NO_CHANGE, NULL);
+}
+
+#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+static int
+write_one_file(Image *output, Image *image, int convert_to_8bit)
+{
+   if (image->opts & FAST_WRITE)
+      image->image.flags |= PNG_IMAGE_FLAG_FAST;
+
+   if (image->opts & USE_STDIO)
+   {
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+#ifndef __COVERITY__
+      FILE *f = tmpfile();
+#else
+      /* Experimental. Coverity says tmpfile() is insecure because it
+       * generates predictable names.
+       *
+       * It is possible to satisfy Coverity by using mkstemp(); however,
+       * any platform supporting mkstemp() undoubtedly has a secure tmpfile()
+       * implementation as well, and doesn't need the fix.  Note that
+       * the fix won't work on platforms that don't support mkstemp().
+       *
+       * https://www.securecoding.cert.org/confluence/display/c/
+       * FIO21-C.+Do+not+create+temporary+files+in+shared+directories
+       * says that most historic implementations of tmpfile() provide
+       * only a limited number of possible temporary file names
+       * (usually 26) before file names are recycled. That article also
+       * provides a secure solution that unfortunately depends upon mkstemp().
+       */
+      char tmpfile[] = "pngstest-XXXXXX";
+      int filedes;
+      FILE *f;
+      umask(0177);
+      filedes = mkstemp(tmpfile);
+      if (filedes < 0)
+        f = NULL;
+      else
+      {
+        f = fdopen(filedes,"w+");
+        /* Hide the filename immediately and ensure that the file does
+         * not exist after the program ends
+         */
+        (void) unlink(tmpfile);
+      }
+#endif
+
+      if (f != NULL)
+      {
+         if (png_image_write_to_stdio(&image->image, f, convert_to_8bit,
+            image->buffer+16, (png_int_32)image->stride, image->colormap))
+         {
+            if (fflush(f) == 0)
+            {
+               rewind(f);
+               initimage(output, image->opts, "tmpfile", image->stride_extra);
+               output->input_file = f;
+               if (!checkopaque(image))
+                  return 0;
+            }
+
+            else
+               return logclose(image, f, "tmpfile", ": flush: ");
+         }
+
+         else
+         {
+            fclose(f);
+            return logerror(image, "tmpfile", ": write failed", "");
+         }
+      }
+
+      else
+         return logerror(image, "tmpfile", ": open: ", strerror(errno));
+#else /* SIMPLIFIED_WRITE_STDIO */
+      return logerror(image, "tmpfile", ": open: unsupported", "");
+#endif /* SIMPLIFIED_WRITE_STDIO */
+   }
+
+   else if (image->opts & USE_FILE)
+   {
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+      static int counter = 0;
+      char name[32];
+
+      sprintf(name, "%s%d.png", tmpf, ++counter);
+
+      if (png_image_write_to_file(&image->image, name, convert_to_8bit,
+         image->buffer+16, (png_int_32)image->stride, image->colormap))
+      {
+         initimage(output, image->opts, output->tmpfile_name,
+            image->stride_extra);
+         /* Afterwards, or freeimage will delete it! */
+         strcpy(output->tmpfile_name, name);
+
+         if (!checkopaque(image))
+            return 0;
+      }
+
+      else
+         return logerror(image, name, ": write failed", "");
+#else /* SIMPLIFIED_WRITE_STDIO */
+      return logerror(image, "stdio", ": open: unsupported", "");
+#endif /* SIMPLIFIED_WRITE_STDIO */
+   }
+
+   else /* use memory */
+   {
+      png_alloc_size_t size;
+
+      if (png_image_write_get_memory_size(image->image, size, convert_to_8bit,
+               image->buffer+16, (png_int_32)image->stride, image->colormap))
+      {
+         /* This is non-fatal but ignoring it was causing serious problems in
+          * the macro to be ignored:
+          */
+         if (size > PNG_IMAGE_PNG_SIZE_MAX(image->image))
+            return logerror(image, "memory", ": PNG_IMAGE_SIZE_MAX wrong", "");
+
+         initimage(output, image->opts, "memory", image->stride_extra);
+         output->input_memory = malloc(size);
+
+         if (output->input_memory != NULL)
+         {
+            output->input_memory_size = size;
+
+            if (png_image_write_to_memory(&image->image, output->input_memory,
+                  &output->input_memory_size, convert_to_8bit, image->buffer+16,
+                  (png_int_32)image->stride, image->colormap))
+            {
+               /* This is also non-fatal but it safes safer to error out anyway:
+                */
+               if (size != output->input_memory_size)
+                  return logerror(image, "memory", ": memory size wrong", "");
+            }
+
+            else
+               return logerror(image, "memory", ": write failed", "");
+         }
+
+         else
+            return logerror(image, "memory", ": out of memory", "");
+      }
+
+      else
+         return logerror(image, "memory", ": get size:", "");
+   }
+
+   /* 'output' has an initialized temporary image, read this back in and compare
+    * this against the original: there should be no change since the original
+    * format was written unmodified unless 'convert_to_8bit' was specified.
+    * However, if the original image was color-mapped, a simple read will zap
+    * the linear, color and maybe alpha flags, this will cause spurious failures
+    * under some circumstances.
+    */
+   if (read_file(output, image->image.format | FORMAT_NO_CHANGE, NULL))
+   {
+      png_uint_32 original_format = image->image.format;
+
+      if (convert_to_8bit)
+         original_format &= ~PNG_FORMAT_FLAG_LINEAR;
+
+      if ((output->image.format & BASE_FORMATS) !=
+         (original_format & BASE_FORMATS))
+         return logerror(image, image->file_name, ": format changed on read: ",
+            output->file_name);
+
+      return compare_two_images(image, output, 0/*via linear*/, NULL);
+   }
+
+   else
+      return logerror(output, output->tmpfile_name,
+         ": read of new file failed", "");
+}
+#endif
+
+static int
+testimage(Image *image, png_uint_32 opts, format_list *pf)
+{
+   int result;
+   Image copy;
+
+   /* Copy the original data, stealing it from 'image' */
+   checkopaque(image);
+   copy = *image;
+
+   copy.opts = opts;
+   copy.buffer = NULL;
+   copy.bufsize = 0;
+   copy.allocsize = 0;
+
+   image->input_file = NULL;
+   image->input_memory = NULL;
+   image->input_memory_size = 0;
+   image->tmpfile_name[0] = 0;
+
+   {
+      png_uint_32 counter;
+      Image output;
+
+      newimage(&output);
+
+      result = 1;
+
+      /* Use the low bit of 'counter' to indicate whether or not to do alpha
+       * removal with a background color or by composting onto the image; this
+       * step gets skipped if it isn't relevant
+       */
+      for (counter=0; counter<2*FORMAT_COUNT; ++counter)
+         if (format_isset(pf, counter >> 1))
+      {
+         png_uint_32 format = counter >> 1;
+
+         png_color background_color;
+         png_colorp background = NULL;
+
+         /* If there is a format change that removes the alpha channel then
+          * the background is relevant.  If the output is 8-bit color-mapped
+          * then a background color *must* be provided, otherwise there are
+          * two tests to do - one with a color, the other with NULL.  The
+          * NULL test happens second.
+          */
+         if ((counter & 1) == 0)
+         {
+            if ((format & PNG_FORMAT_FLAG_ALPHA) == 0 &&
+               (image->image.format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            {
+               /* Alpha/transparency will be removed, the background is
+                * relevant: make it a color the first time
+                */
+               random_color(&background_color);
+               background = &background_color;
+
+               /* BUT if the output is to a color-mapped 8-bit format then
+                * the background must always be a color, so increment 'counter'
+                * to skip the NULL test.
+                */
+               if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 &&
+                  (format & PNG_FORMAT_FLAG_LINEAR) == 0)
+                  ++counter;
+            }
+
+            /* Otherwise an alpha channel is not being eliminated, just leave
+             * background NULL and skip the (counter & 1) NULL test.
+             */
+            else
+               ++counter;
+         }
+         /* else just use NULL for background */
+
+         resetimage(&copy);
+         copy.opts = opts; /* in case read_file needs to change it */
+
+         result = read_file(&copy, format, background);
+         if (!result)
+            break;
+
+         /* Make sure the file just read matches the original file. */
+         result = compare_two_images(image, &copy, 0/*via linear*/, background);
+         if (!result)
+            break;
+
+#        ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+            /* Write the *copy* just made to a new file to make sure the write
+             * side works ok.  Check the conversion to sRGB if the copy is
+             * linear.
+             */
+            output.opts = opts;
+            result = write_one_file(&output, &copy, 0/*convert to 8bit*/);
+            if (!result)
+               break;
+
+            /* Validate against the original too; the background is needed here
+             * as well so that compare_two_images knows what color was used.
+             */
+            result = compare_two_images(image, &output, 0, background);
+            if (!result)
+               break;
+
+            if ((format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
+               (format & PNG_FORMAT_FLAG_COLORMAP) == 0)
+            {
+               /* 'output' is linear, convert to the corresponding sRGB format.
+                */
+               output.opts = opts;
+               result = write_one_file(&output, &copy, 1/*convert to 8bit*/);
+               if (!result)
+                  break;
+
+               /* This may involve a conversion via linear; in the ideal world
+                * this would round-trip correctly, but libpng 1.5.7 is not the
+                * ideal world so allow a drift (error_via_linear).
+                *
+                * 'image' has an alpha channel but 'output' does not then there
+                * will a strip-alpha-channel operation (because 'output' is
+                * linear), handle this by composing on black when doing the
+                * comparison.
+                */
+               result = compare_two_images(image, &output, 1/*via_linear*/,
+                  background);
+               if (!result)
+                  break;
+            }
+#        endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */
+      }
+
+      freeimage(&output);
+   }
+
+   freeimage(&copy);
+
+   return result;
+}
+
+static int
+test_one_file(const char *file_name, format_list *formats, png_uint_32 opts,
+   int stride_extra, int log_pass)
+{
+   int result;
+   Image image;
+
+   if (!(opts & NO_RESEED))
+      reseed(); /* ensure that the random numbers don't depend on file order */
+   newimage(&image);
+   initimage(&image, opts, file_name, stride_extra);
+   result = read_one_file(&image);
+   if (result)
+      result = testimage(&image, opts, formats);
+   freeimage(&image);
+
+   /* Ensure that stderr is flushed into any log file */
+   fflush(stderr);
+
+   if (log_pass)
+   {
+      if (result)
+         printf("PASS:");
+
+      else
+         printf("FAIL:");
+
+#     ifndef PNG_SIMPLIFIED_WRITE_SUPPORTED
+         printf(" (no write)");
+#     endif
+
+      print_opts(opts);
+      printf(" %s\n", file_name);
+      /* stdout may not be line-buffered if it is piped to a file, so: */
+      fflush(stdout);
+   }
+
+   else if (!result)
+      exit(1);
+
+   return result;
+}
+
+int
+main(int argc, char **argv)
+{
+   png_uint_32 opts = FAST_WRITE | STRICT;
+   format_list formats;
+   const char *touch = NULL;
+   int log_pass = 0;
+   int redundant = 0;
+   int stride_extra = 0;
+   int retval = 0;
+   int c;
+
+#if PNG_LIBPNG_VER >= 10700
+      /* This error should not exist in 1.7 or later: */
+      opts |= GBG_ERROR;
+#endif
+
+   init_sRGB_to_d();
+#if 0
+   init_error_via_linear();
+#endif
+   format_init(&formats);
+   reseed(); /* initialize random number seeds */
+
+   for (c=1; c<argc; ++c)
+   {
+      const char *arg = argv[c];
+
+      if (strcmp(arg, "--log") == 0)
+         log_pass = 1;
+      else if (strcmp(arg, "--fresh") == 0)
+      {
+         memset(gpc_error, 0, sizeof gpc_error);
+         memset(gpc_error_via_linear, 0, sizeof gpc_error_via_linear);
+      }
+      else if (strcmp(arg, "--file") == 0)
+#        ifdef PNG_STDIO_SUPPORTED
+            opts |= USE_FILE;
+#        else
+            return SKIP; /* skipped: no support */
+#        endif
+      else if (strcmp(arg, "--memory") == 0)
+         opts &= ~USE_FILE;
+      else if (strcmp(arg, "--stdio") == 0)
+#        ifdef PNG_STDIO_SUPPORTED
+            opts |= USE_STDIO;
+#        else
+            return SKIP; /* skipped: no support */
+#        endif
+      else if (strcmp(arg, "--name") == 0)
+         opts &= ~USE_STDIO;
+      else if (strcmp(arg, "--verbose") == 0)
+         opts |= VERBOSE;
+      else if (strcmp(arg, "--quiet") == 0)
+         opts &= ~VERBOSE;
+      else if (strcmp(arg, "--preserve") == 0)
+         opts |= KEEP_TMPFILES;
+      else if (strcmp(arg, "--nopreserve") == 0)
+         opts &= ~KEEP_TMPFILES;
+      else if (strcmp(arg, "--keep-going") == 0)
+         opts |= KEEP_GOING;
+      else if (strcmp(arg, "--fast") == 0)
+         opts |= FAST_WRITE;
+      else if (strcmp(arg, "--slow") == 0)
+         opts &= ~FAST_WRITE;
+      else if (strcmp(arg, "--accumulate") == 0)
+         opts |= ACCUMULATE;
+      else if (strcmp(arg, "--redundant") == 0)
+         redundant = 1;
+      else if (strcmp(arg, "--stop") == 0)
+         opts &= ~KEEP_GOING;
+      else if (strcmp(arg, "--strict") == 0)
+         opts |= STRICT;
+      else if (strcmp(arg, "--nostrict") == 0)
+         opts &= ~STRICT;
+      else if (strcmp(arg, "--sRGB-16bit") == 0)
+         opts |= sRGB_16BIT;
+      else if (strcmp(arg, "--linear-16bit") == 0)
+         opts &= ~sRGB_16BIT;
+      else if (strcmp(arg, "--noreseed") == 0)
+         opts |= NO_RESEED;
+      else if (strcmp(arg, "--fault-gbg-warning") == 0)
+         opts |= GBG_ERROR;
+      else if (strcmp(arg, "--tmpfile") == 0)
+      {
+         if (c+1 < argc)
+         {
+            if (strlen(argv[++c]) >= sizeof tmpf)
+            {
+               fflush(stdout);
+               fprintf(stderr, "%s: %s is too long for a temp file prefix\n",
+                  argv[0], argv[c]);
+               exit(99);
+            }
+
+            /* Safe: checked above */
+            strncpy(tmpf, argv[c], sizeof (tmpf)-1);
+         }
+
+         else
+         {
+            fflush(stdout);
+            fprintf(stderr, "%s: %s requires a temporary file prefix\n",
+               argv[0], arg);
+            exit(99);
+         }
+      }
+      else if (strcmp(arg, "--touch") == 0)
+      {
+         if (c+1 < argc)
+            touch = argv[++c];
+
+         else
+         {
+            fflush(stdout);
+            fprintf(stderr, "%s: %s requires a file name argument\n",
+               argv[0], arg);
+            exit(99);
+         }
+      }
+      else if (arg[0] == '+')
+      {
+         png_uint_32 format = formatof(arg+1);
+
+         if (format > FORMAT_COUNT)
+            exit(99);
+
+         format_set(&formats, format);
+      }
+      else if (arg[0] == '-' && arg[1] != 0 && (arg[1] != '0' || arg[2] != 0))
+      {
+         fflush(stdout);
+         fprintf(stderr, "%s: unknown option: %s\n", argv[0], arg);
+         exit(99);
+      }
+      else
+      {
+         if (format_is_initial(&formats))
+            format_default(&formats, redundant);
+
+         if (arg[0] == '-')
+         {
+            int term = (arg[1] == '0' ? 0 : '\n');
+            unsigned int ich = 0;
+
+            /* Loop reading files, use a static buffer to simplify this and just
+             * stop if the name gets to long.
+             */
+            static char buffer[4096];
+
+            do
+            {
+               int ch = getchar();
+
+               /* Don't allow '\0' in file names, and terminate with '\n' or,
+                * for -0, just '\0' (use -print0 to find to make this work!)
+                */
+               if (ch == EOF || ch == term || ch == 0)
+               {
+                  buffer[ich] = 0;
+
+                  if (ich > 0 && !test_one_file(buffer, &formats, opts,
+                     stride_extra, log_pass))
+                     retval = 1;
+
+                  if (ch == EOF)
+                     break;
+
+                  ich = 0;
+                  --ich; /* so that the increment below sets it to 0 again */
+               }
+
+               else
+                  buffer[ich] = (char)ch;
+            } while (++ich < sizeof buffer);
+
+            if (ich)
+            {
+               buffer[32] = 0;
+               buffer[4095] = 0;
+               fprintf(stderr, "%s...%s: file name too long\n", buffer,
+                  buffer+(4096-32));
+               exit(99);
+            }
+         }
+
+         else if (!test_one_file(arg, &formats, opts, stride_extra, log_pass))
+            retval = 1;
+      }
+   }
+
+   if (opts & ACCUMULATE)
+   {
+      unsigned int in;
+
+      printf("/* contrib/libtests/pngstest-errors.h\n");
+      printf(" *\n");
+      printf(" * BUILT USING:" PNG_HEADER_VERSION_STRING);
+      printf(" *\n");
+      printf(" * This code is released under the libpng license.\n");
+      printf(" * For conditions of distribution and use, see the disclaimer\n");
+      printf(" * and license in png.h\n");
+      printf(" *\n");
+      printf(" * THIS IS A MACHINE GENERATED FILE: do not edit it directly!\n");
+      printf(" * Instead run:\n");
+      printf(" *\n");
+      printf(" *    pngstest --accumulate\n");
+      printf(" *\n");
+      printf(" * on as many PNG files as possible; at least PNGSuite and\n");
+      printf(" * contrib/libtests/testpngs.\n");
+      printf(" */\n");
+
+      printf("static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =\n");
+      printf("{\n");
+      for (in=0; in<16; ++in)
+      {
+         unsigned int out;
+         printf(" { /* input: %s */\n ", format_names[in]);
+         for (out=0; out<16; ++out)
+         {
+            unsigned int alpha;
+            printf(" {");
+            for (alpha=0; alpha<4; ++alpha)
+            {
+               printf(" %d", gpc_error[in][out][alpha]);
+               if (alpha < 3) putchar(',');
+            }
+            printf(" }");
+            if (out < 15)
+            {
+               putchar(',');
+               if (out % 4 == 3) printf("\n ");
+            }
+         }
+         printf("\n }");
+
+         if (in < 15)
+            putchar(',');
+         else
+            putchar('\n');
+      }
+      printf("};\n");
+
+      printf("static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =\n");
+      printf("{\n");
+      for (in=0; in<16; ++in)
+      {
+         unsigned int out;
+         printf(" { /* input: %s */\n ", format_names[in]);
+         for (out=0; out<4; ++out)
+         {
+            unsigned int alpha;
+            printf(" {");
+            for (alpha=0; alpha<4; ++alpha)
+            {
+               printf(" %d", gpc_error_via_linear[in][out][alpha]);
+               if (alpha < 3) putchar(',');
+            }
+            printf(" }");
+            if (out < 3)
+               putchar(',');
+         }
+         printf("\n }");
+
+         if (in < 15)
+            putchar(',');
+         else
+            putchar('\n');
+      }
+      printf("};\n");
+
+      printf("static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =\n");
+      printf("{\n");
+      for (in=0; in<8; ++in)
+      {
+         unsigned int out;
+         printf(" { /* input: %s */\n ", format_names[in]);
+         for (out=0; out<8; ++out)
+         {
+            unsigned int alpha;
+            printf(" {");
+            for (alpha=0; alpha<4; ++alpha)
+            {
+               printf(" %d", gpc_error_to_colormap[in][out][alpha]);
+               if (alpha < 3) putchar(',');
+            }
+            printf(" }");
+            if (out < 7)
+            {
+               putchar(',');
+               if (out % 4 == 3) printf("\n ");
+            }
+         }
+         printf("\n }");
+
+         if (in < 7)
+            putchar(',');
+         else
+            putchar('\n');
+      }
+      printf("};\n");
+      printf("/* END MACHINE GENERATED */\n");
+   }
+
+   if (retval == 0 && touch != NULL)
+   {
+      FILE *fsuccess = fopen(touch, "wt");
+
+      if (fsuccess != NULL)
+      {
+         int error = 0;
+         fprintf(fsuccess, "PNG simple API tests succeeded\n");
+         fflush(fsuccess);
+         error = ferror(fsuccess);
+
+         if (fclose(fsuccess) || error)
+         {
+            fflush(stdout);
+            fprintf(stderr, "%s: write failed\n", touch);
+            exit(99);
+         }
+      }
+
+      else
+      {
+         fflush(stdout);
+         fprintf(stderr, "%s: open failed\n", touch);
+         exit(99);
+      }
+   }
+
+   return retval;
+}
+
+#else /* !PNG_SIMPLIFIED_READ_SUPPORTED */
+int main(void)
+{
+   fprintf(stderr, "pngstest: no read support in libpng, test skipped\n");
+   /* So the test is skipped: */
+   return SKIP;
+}
+#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
diff --git a/extern/libpng/contrib/libtests/pngunknown.c b/extern/libpng/contrib/libtests/pngunknown.c
new file mode 100644
index 0000000000..05bdd833db
--- /dev/null
+++ b/extern/libpng/contrib/libtests/pngunknown.c
@@ -0,0 +1,1294 @@
+
+/* pngunknown.c - test the read side unknown chunk handling
+ *
+ * Last changed in libpng 1.6.32 [August 24, 2017]
+ * Copyright (c) 2015,2017 Glenn Randers-Pehrson
+ * Written by John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * NOTES:
+ *   This is a C program that is intended to be linked against libpng.  It
+ *   allows the libpng unknown handling code to be tested by interpreting
+ *   arguments to save or discard combinations of chunks.  The program is
+ *   currently just a minimal validation for the built-in libpng facilities.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <setjmp.h>
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+
+/* Since this program tests the ability to change the unknown chunk handling
+ * these must be defined:
+ */
+#if defined(PNG_SET_UNKNOWN_CHUNKS_SUPPORTED) &&\
+   defined(PNG_STDIO_SUPPORTED) &&\
+   defined(PNG_READ_SUPPORTED)
+
+/* One of these must be defined to allow us to find out what happened.  It is
+ * still useful to set unknown chunk handling without either of these in order
+ * to cause *known* chunks to be discarded.  This can be a significant
+ * efficiency gain, but it can't really be tested here.
+ */
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED) ||\
+   defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+
+#if PNG_LIBPNG_VER < 10500
+/* This deliberately lacks the const. */
+typedef png_byte *png_const_bytep;
+
+/* This is copied from 1.5.1 png.h: */
+#define PNG_INTERLACE_ADAM7_PASSES 7
+#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
+#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
+#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
+#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
+   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
+#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
+   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
+#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
+   (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
+#define PNG_COL_FROM_PASS_COL(xIn, pass) \
+   (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
+#define PNG_PASS_MASK(pass,off) ( \
+   ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
+   ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
+#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
+   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
+#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
+   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
+
+/* These are needed too for the default build: */
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+
+/* This comes from pnglibconf.h after 1.5: */
+#define PNG_FP_1 100000
+#define PNG_GAMMA_THRESHOLD_FIXED\
+   ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
+#endif
+
+#if PNG_LIBPNG_VER < 10600
+   /* 1.6.0 constifies many APIs. The following exists to allow pngvalid to be
+    * compiled against earlier versions.
+    */
+#  define png_const_structp png_structp
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+   /* Copied from libpng 1.7.0 png.h */
+#define PNG_u2(b1, b2) (((unsigned int)(b1) << 8) + (b2))
+
+#define PNG_U16(b1, b2) ((png_uint_16)PNG_u2(b1, b2))
+#define PNG_U32(b1, b2, b3, b4)\
+   (((png_uint_32)PNG_u2(b1, b2) << 16) + PNG_u2(b3, b4))
+
+/* Constants for known chunk types.
+ */
+#define png_IDAT PNG_U32( 73,  68,  65,  84)
+#define png_IEND PNG_U32( 73,  69,  78,  68)
+#define png_IHDR PNG_U32( 73,  72,  68,  82)
+#define png_PLTE PNG_U32( 80,  76,  84,  69)
+#define png_bKGD PNG_U32( 98,  75,  71,  68)
+#define png_cHRM PNG_U32( 99,  72,  82,  77)
+#define png_eXIf PNG_U32(101,  88,  73, 102) /* registered July 2017 */
+#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
+#define png_gAMA PNG_U32(103,  65,  77,  65)
+#define png_gIFg PNG_U32(103,  73,  70, 103)
+#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
+#define png_gIFx PNG_U32(103,  73,  70, 120)
+#define png_hIST PNG_U32(104,  73,  83,  84)
+#define png_iCCP PNG_U32(105,  67,  67,  80)
+#define png_iTXt PNG_U32(105,  84,  88, 116)
+#define png_oFFs PNG_U32(111,  70,  70, 115)
+#define png_pCAL PNG_U32(112,  67,  65,  76)
+#define png_pHYs PNG_U32(112,  72,  89, 115)
+#define png_sBIT PNG_U32(115,  66,  73,  84)
+#define png_sCAL PNG_U32(115,  67,  65,  76)
+#define png_sPLT PNG_U32(115,  80,  76,  84)
+#define png_sRGB PNG_U32(115,  82,  71,  66)
+#define png_sTER PNG_U32(115,  84,  69,  82)
+#define png_tEXt PNG_U32(116,  69,  88, 116)
+#define png_tIME PNG_U32(116,  73,  77,  69)
+#define png_tRNS PNG_U32(116,  82,  78,  83)
+#define png_zTXt PNG_U32(122,  84,  88, 116)
+
+/* Test on flag values as defined in the spec (section 5.4): */
+#define PNG_CHUNK_ANCILLARY(c)    (1 & ((c) >> 29))
+#define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
+#define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
+#define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
+#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
+
+#endif /* PNG_LIBPNG_VER < 10700 */
+
+#ifdef __cplusplus
+#  define this not_the_cpp_this
+#  define new not_the_cpp_new
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+/* Unused formal parameter errors are removed using the following macro which is
+ * expected to have no bad effects on performance.
+ */
+#ifndef UNUSED
+#  if defined(__GNUC__) || defined(_MSC_VER)
+#     define UNUSED(param) (void)param;
+#  else
+#     define UNUSED(param)
+#  endif
+#endif
+
+/* Types of chunks not known to libpng */
+#define png_vpAg PNG_U32(118, 112, 65, 103)
+
+/* Chunk information */
+#define PNG_INFO_tEXt 0x10000000U
+#define PNG_INFO_iTXt 0x20000000U
+#define PNG_INFO_zTXt 0x40000000U
+
+#define PNG_INFO_sTER 0x01000000U
+#define PNG_INFO_vpAg 0x02000000U
+
+#define ABSENT  0
+#define START   1
+#define END     2
+
+static struct
+{
+   char        name[5];
+   png_uint_32 flag;
+   png_uint_32 tag;
+   int         unknown;    /* Chunk not known to libpng */
+   int         all;        /* Chunk set by the '-1' option */
+   int         position;   /* position in pngtest.png */
+   int         keep;       /* unknown handling setting */
+} chunk_info[] = {
+   /* Critical chunks */
+   { "IDAT", PNG_INFO_IDAT, png_IDAT, 0, 0,  START, 0 }, /* must be [0] */
+   { "PLTE", PNG_INFO_PLTE, png_PLTE, 0, 0, ABSENT, 0 },
+
+   /* Non-critical chunks that libpng handles */
+   /* This is a mess but it seems to be the only way to do it - there is no way
+    * to check for a definition outside a #if.
+    */
+   { "bKGD", PNG_INFO_bKGD, png_bKGD,
+#     ifdef PNG_READ_bKGD_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "cHRM", PNG_INFO_cHRM, png_cHRM,
+#     ifdef PNG_READ_cHRM_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "eXIf", PNG_INFO_eXIf, png_eXIf,
+#     ifdef PNG_READ_eXIf_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  END, 0 },
+   { "gAMA", PNG_INFO_gAMA, png_gAMA,
+#     ifdef PNG_READ_gAMA_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "hIST", PNG_INFO_hIST, png_hIST,
+#     ifdef PNG_READ_hIST_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1, ABSENT, 0 },
+   { "iCCP", PNG_INFO_iCCP, png_iCCP,
+#     ifdef PNG_READ_iCCP_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1, ABSENT, 0 },
+   { "iTXt", PNG_INFO_iTXt, png_iTXt,
+#     ifdef PNG_READ_iTXt_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1, ABSENT, 0 },
+   { "oFFs", PNG_INFO_oFFs, png_oFFs,
+#     ifdef PNG_READ_oFFs_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "pCAL", PNG_INFO_pCAL, png_pCAL,
+#     ifdef PNG_READ_pCAL_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "pHYs", PNG_INFO_pHYs, png_pHYs,
+#     ifdef PNG_READ_pHYs_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "sBIT", PNG_INFO_sBIT, png_sBIT,
+#     ifdef PNG_READ_sBIT_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "sCAL", PNG_INFO_sCAL, png_sCAL,
+#     ifdef PNG_READ_sCAL_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "sPLT", PNG_INFO_sPLT, png_sPLT,
+#     ifdef PNG_READ_sPLT_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1, ABSENT, 0 },
+   { "sRGB", PNG_INFO_sRGB, png_sRGB,
+#     ifdef PNG_READ_sRGB_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "tEXt", PNG_INFO_tEXt, png_tEXt,
+#     ifdef PNG_READ_tEXt_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "tIME", PNG_INFO_tIME, png_tIME,
+#     ifdef PNG_READ_tIME_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "tRNS", PNG_INFO_tRNS, png_tRNS,
+#     ifdef PNG_READ_tRNS_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      0, ABSENT, 0 },
+   { "zTXt", PNG_INFO_zTXt, png_zTXt,
+#     ifdef PNG_READ_zTXt_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,    END, 0 },
+
+   /* No libpng handling */
+   { "sTER", PNG_INFO_sTER, png_sTER, 1, 1,  START, 0 },
+   { "vpAg", PNG_INFO_vpAg, png_vpAg, 1, 0,  START, 0 },
+};
+
+#define NINFO ((int)((sizeof chunk_info)/(sizeof chunk_info[0])))
+
+static void
+clear_keep(void)
+{
+   int i = NINFO;
+   while (--i >= 0)
+      chunk_info[i].keep = 0;
+}
+
+static int
+find(const char *name)
+{
+   int i = NINFO;
+   while (--i >= 0)
+   {
+      if (memcmp(chunk_info[i].name, name, 4) == 0)
+         break;
+   }
+
+   return i;
+}
+
+static int
+findb(const png_byte *name)
+{
+   int i = NINFO;
+   while (--i >= 0)
+   {
+      if (memcmp(chunk_info[i].name, name, 4) == 0)
+         break;
+   }
+
+   return i;
+}
+
+static int
+find_by_flag(png_uint_32 flag)
+{
+   int i = NINFO;
+
+   while (--i >= 0) if (chunk_info[i].flag == flag) return i;
+
+   fprintf(stderr, "pngunknown: internal error\n");
+   exit(4);
+}
+
+static int
+ancillary(const char *name)
+{
+   return PNG_CHUNK_ANCILLARY(PNG_U32(name[0], name[1], name[2], name[3]));
+}
+
+#ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+static int
+ancillaryb(const png_byte *name)
+{
+   return PNG_CHUNK_ANCILLARY(PNG_U32(name[0], name[1], name[2], name[3]));
+}
+#endif
+
+/* Type of an error_ptr */
+typedef struct
+{
+   jmp_buf     error_return;
+   png_structp png_ptr;
+   png_infop   info_ptr, end_ptr;
+   png_uint_32 before_IDAT;
+   png_uint_32 after_IDAT;
+   int         error_count;
+   int         warning_count;
+   int         keep; /* the default value */
+   const char *program;
+   const char *file;
+   const char *test;
+} display;
+
+static const char init[] = "initialization";
+static const char cmd[] = "command line";
+
+static void
+init_display(display *d, const char *program)
+{
+   memset(d, 0, sizeof *d);
+   d->png_ptr = NULL;
+   d->info_ptr = d->end_ptr = NULL;
+   d->error_count = d->warning_count = 0;
+   d->program = program;
+   d->file = program;
+   d->test = init;
+}
+
+static void
+clean_display(display *d)
+{
+   png_destroy_read_struct(&d->png_ptr, &d->info_ptr, &d->end_ptr);
+
+   /* This must not happen - it might cause an app crash */
+   if (d->png_ptr != NULL || d->info_ptr != NULL || d->end_ptr != NULL)
+   {
+      fprintf(stderr, "%s(%s): png_destroy_read_struct error\n", d->file,
+         d->test);
+      exit(1);
+   }
+}
+
+PNG_FUNCTION(void, display_exit, (display *d), static PNG_NORETURN)
+{
+   ++(d->error_count);
+
+   if (d->png_ptr != NULL)
+      clean_display(d);
+
+   /* During initialization and if this is a single command line argument set
+    * exit now - there is only one test, otherwise longjmp to do the next test.
+    */
+   if (d->test == init || d->test == cmd)
+      exit(1);
+
+   longjmp(d->error_return, 1);
+}
+
+static int
+display_rc(const display *d, int strict)
+{
+   return d->error_count + (strict ? d->warning_count : 0);
+}
+
+/* libpng error and warning callbacks */
+PNG_FUNCTION(void, (PNGCBAPI error), (png_structp png_ptr, const char *message),
+   static PNG_NORETURN)
+{
+   display *d = (display*)png_get_error_ptr(png_ptr);
+
+   fprintf(stderr, "%s(%s): libpng error: %s\n", d->file, d->test, message);
+   display_exit(d);
+}
+
+static void PNGCBAPI
+warning(png_structp png_ptr, const char *message)
+{
+   display *d = (display*)png_get_error_ptr(png_ptr);
+
+   fprintf(stderr, "%s(%s): libpng warning: %s\n", d->file, d->test, message);
+   ++(d->warning_count);
+}
+
+static png_uint_32
+get_valid(display *d, png_infop info_ptr)
+{
+   png_uint_32 flags = png_get_valid(d->png_ptr, info_ptr, (png_uint_32)~0);
+
+   /* Map the text chunks back into the flags */
+   {
+      png_textp text;
+      png_uint_32 ntext = png_get_text(d->png_ptr, info_ptr, &text, NULL);
+
+      while (ntext > 0) switch (text[--ntext].compression)
+      {
+         case -1:
+            flags |= PNG_INFO_tEXt;
+            break;
+         case 0:
+            flags |= PNG_INFO_zTXt;
+            break;
+         case 1:
+         case 2:
+            flags |= PNG_INFO_iTXt;
+            break;
+         default:
+            fprintf(stderr, "%s(%s): unknown text compression %d\n", d->file,
+               d->test, text[ntext].compression);
+            display_exit(d);
+      }
+   }
+
+   return flags;
+}
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+static int PNGCBAPI
+read_callback(png_structp pp, png_unknown_chunkp pc)
+{
+   /* This function mimics the behavior of png_set_keep_unknown_chunks by
+    * returning '0' to keep the chunk and '1' to discard it.
+    */
+   display *d = voidcast(display*, png_get_user_chunk_ptr(pp));
+   int chunk = findb(pc->name);
+   int keep, discard;
+
+   if (chunk < 0) /* not one in our list, so not a known chunk */
+      keep = d->keep;
+
+   else
+   {
+      keep = chunk_info[chunk].keep;
+      if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+      {
+         /* See the comments in png.h - use the default for unknown chunks,
+          * do not keep known chunks.
+          */
+         if (chunk_info[chunk].unknown)
+            keep = d->keep;
+
+         else
+            keep = PNG_HANDLE_CHUNK_NEVER;
+      }
+   }
+
+   switch (keep)
+   {
+      default:
+         fprintf(stderr, "%s(%s): %d: unrecognized chunk option\n", d->file,
+            d->test, chunk_info[chunk].keep);
+         display_exit(d);
+
+      case PNG_HANDLE_CHUNK_AS_DEFAULT:
+      case PNG_HANDLE_CHUNK_NEVER:
+         discard = 1/*handled; discard*/;
+         break;
+
+      case PNG_HANDLE_CHUNK_IF_SAFE:
+      case PNG_HANDLE_CHUNK_ALWAYS:
+         discard = 0/*not handled; keep*/;
+         break;
+   }
+
+   /* Also store information about this chunk in the display, the relevant flag
+    * is set if the chunk is to be kept ('not handled'.)
+    */
+   if (chunk >= 0) if (!discard) /* stupidity to stop a GCC warning */
+   {
+      png_uint_32 flag = chunk_info[chunk].flag;
+
+      if (pc->location & PNG_AFTER_IDAT)
+         d->after_IDAT |= flag;
+
+      else
+         d->before_IDAT |= flag;
+   }
+
+   /* However if there is no support to store unknown chunks don't ask libpng to
+    * do it; there will be an png_error.
+    */
+#  ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+      return discard;
+#  else
+      return 1; /*handled; discard*/
+#  endif
+}
+#endif /* READ_USER_CHUNKS_SUPPORTED */
+
+#ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+static png_uint_32
+get_unknown(display *d, png_infop info_ptr, int after_IDAT)
+{
+   /* Create corresponding 'unknown' flags */
+   png_uint_32 flags = 0;
+
+   UNUSED(after_IDAT)
+
+   {
+      png_unknown_chunkp unknown;
+      int num_unknown = png_get_unknown_chunks(d->png_ptr, info_ptr, &unknown);
+
+      while (--num_unknown >= 0)
+      {
+         int chunk = findb(unknown[num_unknown].name);
+
+         /* Chunks not known to pngunknown must be validated here; since they
+          * must also be unknown to libpng the 'display->keep' behavior should
+          * have been used.
+          */
+         if (chunk < 0) switch (d->keep)
+         {
+            default: /* impossible */
+            case PNG_HANDLE_CHUNK_AS_DEFAULT:
+            case PNG_HANDLE_CHUNK_NEVER:
+               fprintf(stderr, "%s(%s): %s: %s: unknown chunk saved\n",
+                  d->file, d->test, d->keep ? "discard" : "default",
+                  unknown[num_unknown].name);
+               ++(d->error_count);
+               break;
+
+            case PNG_HANDLE_CHUNK_IF_SAFE:
+               if (!ancillaryb(unknown[num_unknown].name))
+               {
+                  fprintf(stderr,
+                     "%s(%s): if-safe: %s: unknown critical chunk saved\n",
+                     d->file, d->test, unknown[num_unknown].name);
+                  ++(d->error_count);
+                  break;
+               }
+               /* FALLTHROUGH */ /* (safe) */
+            case PNG_HANDLE_CHUNK_ALWAYS:
+               break;
+         }
+
+         else
+            flags |= chunk_info[chunk].flag;
+      }
+   }
+
+   return flags;
+}
+#else /* SAVE_UNKNOWN_CHUNKS */
+static png_uint_32
+get_unknown(display *d, png_infop info_ptr, int after_IDAT)
+   /* Otherwise this will return the cached values set by any user callback */
+{
+   UNUSED(info_ptr);
+
+   if (after_IDAT)
+      return d->after_IDAT;
+
+   else
+      return d->before_IDAT;
+}
+
+#  ifndef PNG_READ_USER_CHUNKS_SUPPORTED
+      /* The #defines above should mean this is never reached, it's just here as
+       * a check to ensure the logic is correct.
+       */
+#     error No store support and no user chunk support, this will not work
+#  endif /* READ_USER_CHUNKS */
+#endif /* SAVE_UNKNOWN_CHUNKS */
+
+static int
+check(FILE *fp, int argc, const char **argv, png_uint_32p flags/*out*/,
+   display *d, int set_callback)
+{
+   int i, npasses, ipass;
+   png_uint_32 height;
+
+   d->keep = PNG_HANDLE_CHUNK_AS_DEFAULT;
+   d->before_IDAT = 0;
+   d->after_IDAT = 0;
+
+   /* Some of these errors are permanently fatal and cause an exit here, others
+    * are per-test and cause an error return.
+    */
+   d->png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, d, error,
+      warning);
+   if (d->png_ptr == NULL)
+   {
+      fprintf(stderr, "%s(%s): could not allocate png struct\n", d->file,
+         d->test);
+      /* Terminate here, this error is not test specific. */
+      exit(1);
+   }
+
+   d->info_ptr = png_create_info_struct(d->png_ptr);
+   d->end_ptr = png_create_info_struct(d->png_ptr);
+   if (d->info_ptr == NULL || d->end_ptr == NULL)
+   {
+      fprintf(stderr, "%s(%s): could not allocate png info\n", d->file,
+         d->test);
+      clean_display(d);
+      exit(1);
+   }
+
+   png_init_io(d->png_ptr, fp);
+
+#  ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+      /* This is only done if requested by the caller; it interferes with the
+       * standard store/save mechanism.
+       */
+      if (set_callback)
+         png_set_read_user_chunk_fn(d->png_ptr, d, read_callback);
+#  else
+      UNUSED(set_callback)
+#  endif
+
+   /* Handle each argument in turn; multiple settings are possible for the same
+    * chunk and multiple calls will occur (the last one should override all
+    * preceding ones).
+    */
+   for (i=0; i<argc; ++i)
+   {
+      const char *equals = strchr(argv[i], '=');
+
+      if (equals != NULL)
+      {
+         int chunk, option;
+
+         if (strcmp(equals+1, "default") == 0)
+            option = PNG_HANDLE_CHUNK_AS_DEFAULT;
+         else if (strcmp(equals+1, "discard") == 0)
+            option = PNG_HANDLE_CHUNK_NEVER;
+         else if (strcmp(equals+1, "if-safe") == 0)
+            option = PNG_HANDLE_CHUNK_IF_SAFE;
+         else if (strcmp(equals+1, "save") == 0)
+            option = PNG_HANDLE_CHUNK_ALWAYS;
+         else
+         {
+            fprintf(stderr, "%s(%s): %s: unrecognized chunk option\n", d->file,
+               d->test, argv[i]);
+            display_exit(d);
+         }
+
+         switch (equals - argv[i])
+         {
+            case 4: /* chunk name */
+               chunk = find(argv[i]);
+
+               if (chunk >= 0)
+               {
+                  /* These #if tests have the effect of skipping the arguments
+                   * if SAVE support is unavailable - we can't do a useful test
+                   * in this case, so we just check the arguments!  This could
+                   * be improved in the future by using the read callback.
+                   */
+#                 if PNG_LIBPNG_VER >= 10700 &&\
+                     !defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+                     if (option < PNG_HANDLE_CHUNK_IF_SAFE)
+#                 endif /* 1.7+ SAVE_UNKNOWN_CHUNKS */
+                  {
+                     png_byte name[5];
+
+                     memcpy(name, chunk_info[chunk].name, 5);
+                     png_set_keep_unknown_chunks(d->png_ptr, option, name, 1);
+                     chunk_info[chunk].keep = option;
+                  }
+                  continue;
+               }
+
+               break;
+
+            case 7: /* default */
+               if (memcmp(argv[i], "default", 7) == 0)
+               {
+#                 if PNG_LIBPNG_VER >= 10700 &&\
+                     !defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+                     if (option < PNG_HANDLE_CHUNK_IF_SAFE)
+#                 endif /* 1.7+ SAVE_UNKNOWN_CHUNKS */
+                     png_set_keep_unknown_chunks(d->png_ptr, option, NULL, 0);
+
+                  d->keep = option;
+                  continue;
+               }
+
+               break;
+
+            case 3: /* all */
+               if (memcmp(argv[i], "all", 3) == 0)
+               {
+#                 if PNG_LIBPNG_VER >= 10700 &&\
+                     !defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+                     if (option < PNG_HANDLE_CHUNK_IF_SAFE)
+#                 endif /* 1.7+ SAVE_UNKNOWN_CHUNKS */
+                     png_set_keep_unknown_chunks(d->png_ptr, option, NULL, -1);
+
+                  d->keep = option;
+
+                  for (chunk = 0; chunk < NINFO; ++chunk)
+                     if (chunk_info[chunk].all)
+                        chunk_info[chunk].keep = option;
+                  continue;
+               }
+
+               break;
+
+            default: /* some misplaced = */
+
+               break;
+         }
+      }
+
+      fprintf(stderr, "%s(%s): %s: unrecognized chunk argument\n", d->file,
+         d->test, argv[i]);
+      display_exit(d);
+   }
+
+   png_read_info(d->png_ptr, d->info_ptr);
+
+   switch (png_get_interlace_type(d->png_ptr, d->info_ptr))
+   {
+      case PNG_INTERLACE_NONE:
+         npasses = 1;
+         break;
+
+      case PNG_INTERLACE_ADAM7:
+         npasses = PNG_INTERLACE_ADAM7_PASSES;
+         break;
+
+      default:
+         /* Hard error because it is not test specific */
+         fprintf(stderr, "%s(%s): invalid interlace type\n", d->file, d->test);
+         clean_display(d);
+         exit(1);
+   }
+
+   /* Skip the image data, if IDAT is not being handled then don't do this
+    * because it will cause a CRC error.
+    */
+   if (chunk_info[0/*IDAT*/].keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+   {
+      png_start_read_image(d->png_ptr);
+      height = png_get_image_height(d->png_ptr, d->info_ptr);
+
+      if (npasses > 1)
+      {
+         png_uint_32 width = png_get_image_width(d->png_ptr, d->info_ptr);
+
+         for (ipass=0; ipass<npasses; ++ipass)
+         {
+            png_uint_32 wPass = PNG_PASS_COLS(width, ipass);
+
+            if (wPass > 0)
+            {
+               png_uint_32 y;
+
+               for (y=0; y<height; ++y) if (PNG_ROW_IN_INTERLACE_PASS(y, ipass))
+                  png_read_row(d->png_ptr, NULL, NULL);
+            }
+         }
+      } /* interlaced */
+
+      else /* not interlaced */
+      {
+         png_uint_32 y;
+
+         for (y=0; y<height; ++y)
+            png_read_row(d->png_ptr, NULL, NULL);
+      }
+   }
+
+   png_read_end(d->png_ptr, d->end_ptr);
+
+   flags[0] = get_valid(d, d->info_ptr);
+   flags[1] = get_unknown(d, d->info_ptr, 0/*before IDAT*/);
+
+   /* Only png_read_png sets PNG_INFO_IDAT! */
+   flags[chunk_info[0/*IDAT*/].keep != PNG_HANDLE_CHUNK_AS_DEFAULT] |=
+      PNG_INFO_IDAT;
+
+   flags[2] = get_valid(d, d->end_ptr);
+   flags[3] = get_unknown(d, d->end_ptr, 1/*after IDAT*/);
+
+   clean_display(d);
+
+   return d->keep;
+}
+
+static void
+check_error(display *d, png_uint_32 flags, const char *message)
+{
+   while (flags)
+   {
+      png_uint_32 flag = flags & -(png_int_32)flags;
+      int i = find_by_flag(flag);
+
+      fprintf(stderr, "%s(%s): chunk %s: %s\n", d->file, d->test,
+         chunk_info[i].name, message);
+      ++(d->error_count);
+
+      flags &= ~flag;
+   }
+}
+
+static void
+check_handling(display *d, int def, png_uint_32 chunks, png_uint_32 known,
+   png_uint_32 unknown, const char *position, int set_callback)
+{
+   while (chunks)
+   {
+      png_uint_32 flag = chunks & -(png_int_32)chunks;
+      int i = find_by_flag(flag);
+      int keep = chunk_info[i].keep;
+      const char *type;
+      const char *errorx = NULL;
+
+      if (chunk_info[i].unknown)
+      {
+         if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+         {
+            type = "UNKNOWN (default)";
+            keep = def;
+         }
+
+         else
+            type = "UNKNOWN (specified)";
+
+         if (flag & known)
+            errorx = "chunk processed";
+
+         else switch (keep)
+         {
+            case PNG_HANDLE_CHUNK_AS_DEFAULT:
+               if (flag & unknown)
+                  errorx = "DEFAULT: unknown chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_NEVER:
+               if (flag & unknown)
+                  errorx = "DISCARD: unknown chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_IF_SAFE:
+               if (ancillary(chunk_info[i].name))
+               {
+                  if (!(flag & unknown))
+                     errorx = "IF-SAFE: unknown ancillary chunk lost";
+               }
+
+               else if (flag & unknown)
+                  errorx = "IF-SAFE: unknown critical chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_ALWAYS:
+               if (!(flag & unknown))
+                  errorx = "SAVE: unknown chunk lost";
+               break;
+
+            default:
+               errorx = "internal error: bad keep";
+               break;
+         }
+      } /* unknown chunk */
+
+      else /* known chunk */
+      {
+         type = "KNOWN";
+
+         if (flag & known)
+         {
+            /* chunk was processed, it won't have been saved because that is
+             * caught below when checking for inconsistent processing.
+             */
+            if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
+               errorx = "!DEFAULT: known chunk processed";
+         }
+
+         else /* not processed */ switch (keep)
+         {
+            case PNG_HANDLE_CHUNK_AS_DEFAULT:
+               errorx = "DEFAULT: known chunk not processed";
+               break;
+
+            case PNG_HANDLE_CHUNK_NEVER:
+               if (flag & unknown)
+                  errorx = "DISCARD: known chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_IF_SAFE:
+               if (ancillary(chunk_info[i].name))
+               {
+                  if (!(flag & unknown))
+                     errorx = "IF-SAFE: known ancillary chunk lost";
+               }
+
+               else if (flag & unknown)
+                  errorx = "IF-SAFE: known critical chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_ALWAYS:
+               if (!(flag & unknown))
+                  errorx = "SAVE: known chunk lost";
+               break;
+
+            default:
+               errorx = "internal error: bad keep (2)";
+               break;
+         }
+      }
+
+      if (errorx != NULL)
+      {
+         ++(d->error_count);
+         fprintf(stderr, "%s(%s%s): %s %s %s: %s\n", d->file, d->test,
+            set_callback ? ",callback" : "",
+            type, chunk_info[i].name, position, errorx);
+      }
+
+      chunks &= ~flag;
+   }
+}
+
+static void
+perform_one_test(FILE *fp, int argc, const char **argv,
+   png_uint_32 *default_flags, display *d, int set_callback)
+{
+   int def;
+   png_uint_32 flags[2][4];
+
+   rewind(fp);
+   clear_keep();
+   memcpy(flags[0], default_flags, sizeof flags[0]);
+
+   def = check(fp, argc, argv, flags[1], d, set_callback);
+
+   /* If IDAT is being handled as unknown the image read is skipped and all the
+    * IDATs after the first end up in the end info struct, so in this case add
+    * IDAT to the list of unknowns.  (Do this after 'check' above sets the
+    * chunk_info 'keep' fields.)
+    *
+    * Note that the flag setting has to be in the 'known' field to avoid
+    * triggering the consistency check below and the flag must only be set if
+    * there are multiple IDATs, so if the check above did find an unknown IDAT
+    * after IDAT.
+    */
+   if (chunk_info[0/*IDAT*/].keep != PNG_HANDLE_CHUNK_AS_DEFAULT &&
+       (flags[1][3] & PNG_INFO_IDAT) != 0)
+      flags[0][2] |= PNG_INFO_IDAT;
+
+   /* Chunks should either be known or unknown, never both and this should apply
+    * whether the chunk is before or after the IDAT (actually, the app can
+    * probably change this by swapping the handling after the image, but this
+    * test does not do that.)
+    */
+   check_error(d, (flags[0][0]|flags[0][2]) & (flags[0][1]|flags[0][3]),
+      "chunk handled inconsistently in count tests");
+   check_error(d, (flags[1][0]|flags[1][2]) & (flags[1][1]|flags[1][3]),
+      "chunk handled inconsistently in option tests");
+
+   /* Now find out what happened to each chunk before and after the IDAT and
+    * determine if the behavior was correct.  First some basic sanity checks,
+    * any known chunk should be known in the original count, any unknown chunk
+    * should be either known or unknown in the original.
+    */
+   {
+      png_uint_32 test;
+
+      test = flags[1][0] & ~flags[0][0];
+      check_error(d, test, "new known chunk before IDAT");
+      test = flags[1][1] & ~(flags[0][0] | flags[0][1]);
+      check_error(d, test, "new unknown chunk before IDAT");
+      test = flags[1][2] & ~flags[0][2];
+      check_error(d, test, "new known chunk after IDAT");
+      test = flags[1][3] & ~(flags[0][2] | flags[0][3]);
+      check_error(d, test, "new unknown chunk after IDAT");
+   }
+
+   /* Now each chunk in the original list should have been handled according to
+    * the options set for that chunk, regardless of whether libpng knows about
+    * it or not.
+    */
+   check_handling(d, def, flags[0][0] | flags[0][1], flags[1][0], flags[1][1],
+      "before IDAT", set_callback);
+   check_handling(d, def, flags[0][2] | flags[0][3], flags[1][2], flags[1][3],
+      "after IDAT", set_callback);
+}
+
+static void
+perform_one_test_safe(FILE *fp, int argc, const char **argv,
+   png_uint_32 *default_flags, display *d, const char *test)
+{
+   if (setjmp(d->error_return) == 0)
+   {
+      d->test = test; /* allow use of d->error_return */
+#     ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+         perform_one_test(fp, argc, argv, default_flags, d, 0);
+#     endif
+#     ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+         perform_one_test(fp, argc, argv, default_flags, d, 1);
+#     endif
+      d->test = init; /* prevent use of d->error_return */
+   }
+}
+
+static const char *standard_tests[] =
+{
+ "discard", "default=discard", 0,
+ "save", "default=save", 0,
+ "if-safe", "default=if-safe", 0,
+ "vpAg", "vpAg=if-safe", 0,
+ "sTER", "sTER=if-safe", 0,
+ "IDAT", "default=discard", "IDAT=save", 0,
+ "sAPI", "bKGD=save", "cHRM=save", "gAMA=save", "all=discard", "iCCP=save",
+   "sBIT=save", "sRGB=save", "eXIf=save", 0,
+ 0/*end*/
+};
+
+static PNG_NORETURN void
+usage(const char *program, const char *reason)
+{
+   fprintf(stderr, "pngunknown: %s: usage:\n %s [--strict] "
+      "--default|{(CHNK|default|all)=(default|discard|if-safe|save)} "
+      "testfile.png\n", reason, program);
+   exit(99);
+}
+
+int
+main(int argc, const char **argv)
+{
+   FILE *fp;
+   png_uint_32 default_flags[4/*valid,unknown{before,after}*/];
+   int strict = 0, default_tests = 0;
+   const char *count_argv = "default=save";
+   const char *touch_file = NULL;
+   display d;
+
+   init_display(&d, argv[0]);
+
+   while (++argv, --argc > 0)
+   {
+      if (strcmp(*argv, "--strict") == 0)
+         strict = 1;
+
+      else if (strcmp(*argv, "--default") == 0)
+         default_tests = 1;
+
+      else if (strcmp(*argv, "--touch") == 0)
+      {
+         if (argc > 1)
+            touch_file = *++argv, --argc;
+
+         else
+            usage(d.program, "--touch: missing file name");
+      }
+
+      else
+         break;
+   }
+
+   /* A file name is required, but there should be no other arguments if
+    * --default was specified.
+    */
+   if (argc <= 0)
+      usage(d.program, "missing test file");
+
+   /* GCC BUG: if (default_tests && argc != 1) triggers some weird GCC argc
+    * optimization which causes warnings with -Wstrict-overflow!
+    */
+   else if (default_tests) if (argc != 1)
+      usage(d.program, "extra arguments");
+
+   /* The name of the test file is the last argument; remove it. */
+   d.file = argv[--argc];
+
+   fp = fopen(d.file, "rb");
+   if (fp == NULL)
+   {
+      perror(d.file);
+      exit(99);
+   }
+
+   /* First find all the chunks, known and unknown, in the test file, a failure
+    * here aborts the whole test.
+    *
+    * If 'save' is supported then the normal saving method should happen,
+    * otherwise if 'read' is supported then the read callback will do the
+    * same thing.  If both are supported the 'read' callback won't be
+    * instantiated by default.  If 'save' is *not* supported then a user
+    * callback is required even though we can call png_get_unknown_chunks.
+    */
+   if (check(fp, 1, &count_argv, default_flags, &d,
+#     ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+         0
+#     else
+         1
+#     endif
+      ) != PNG_HANDLE_CHUNK_ALWAYS)
+   {
+      fprintf(stderr, "%s: %s: internal error\n", d.program, d.file);
+      exit(99);
+   }
+
+   /* Now find what the various supplied options cause to change: */
+   if (!default_tests)
+   {
+      d.test = cmd; /* acts as a flag to say exit, do not longjmp */
+#     ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+         perform_one_test(fp, argc, argv, default_flags, &d, 0);
+#     endif
+#     ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+         perform_one_test(fp, argc, argv, default_flags, &d, 1);
+#     endif
+      d.test = init;
+   }
+
+   else
+   {
+      const char **test = standard_tests;
+
+      /* Set the exit_test pointer here so we can continue after a libpng error.
+       * NOTE: this leaks memory because the png_struct data from the failing
+       * test is never freed.
+       */
+      while (*test)
+      {
+         const char *this_test = *test++;
+         const char **next = test;
+         int count = display_rc(&d, strict), new_count;
+         const char *result;
+         int arg_count = 0;
+
+         while (*next) ++next, ++arg_count;
+
+         perform_one_test_safe(fp, arg_count, test, default_flags, &d,
+            this_test);
+
+         new_count = display_rc(&d, strict);
+
+         if (new_count == count)
+            result = "PASS";
+
+         else
+            result = "FAIL";
+
+         printf("%s: %s %s\n", result, d.program, this_test);
+
+         test = next+1;
+      }
+   }
+
+   fclose(fp);
+
+   if (display_rc(&d, strict) == 0)
+   {
+      /* Success, touch the success file if appropriate */
+      if (touch_file != NULL)
+      {
+         FILE *fsuccess = fopen(touch_file, "wt");
+
+         if (fsuccess != NULL)
+         {
+            int err = 0;
+            fprintf(fsuccess, "PNG unknown tests succeeded\n");
+            fflush(fsuccess);
+            err = ferror(fsuccess);
+
+            if (fclose(fsuccess) || err)
+            {
+               fprintf(stderr, "%s: write failed\n", touch_file);
+               exit(99);
+            }
+         }
+
+         else
+         {
+            fprintf(stderr, "%s: open failed\n", touch_file);
+            exit(99);
+         }
+      }
+
+      return 0;
+   }
+
+   return 1;
+}
+
+#else /* !(READ_USER_CHUNKS || SAVE_UNKNOWN_CHUNKS) */
+int
+main(void)
+{
+   fprintf(stderr,
+      " test ignored: no support to find out about unknown chunks\n");
+   /* So the test is skipped: */
+   return SKIP;
+}
+#endif /* READ_USER_CHUNKS || SAVE_UNKNOWN_CHUNKS */
+
+#else /* !(SET_UNKNOWN_CHUNKS && READ) */
+int
+main(void)
+{
+   fprintf(stderr,
+      " test ignored: no support to modify unknown chunk handling\n");
+   /* So the test is skipped: */
+   return SKIP;
+}
+#endif /* SET_UNKNOWN_CHUNKS && READ*/
diff --git a/extern/libpng/contrib/libtests/pngvalid.c b/extern/libpng/contrib/libtests/pngvalid.c
new file mode 100644
index 0000000000..d800110c7a
--- /dev/null
+++ b/extern/libpng/contrib/libtests/pngvalid.c
@@ -0,0 +1,12230 @@
+
+/* pngvalid.c - validate libpng by constructing then reading png files.
+ *
+ * Last changed in libpng 1.6.31 [July 27, 2017]
+ * Copyright (c) 2014-2017 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * NOTES:
+ *   This is a C program that is intended to be linked against libpng.  It
+ *   generates bitmaps internally, stores them as PNG files (using the
+ *   sequential write code) then reads them back (using the sequential
+ *   read code) and validates that the result has the correct data.
+ *
+ *   The program can be modified and extended to test the correctness of
+ *   transformations performed by libpng.
+ */
+
+#define _POSIX_SOURCE 1
+#define _ISOC99_SOURCE 1 /* For floating point */
+#define _GNU_SOURCE 1 /* For the floating point exception extension */
+#define _BSD_SOURCE 1 /* For the floating point exception extension */
+
+#include <signal.h>
+#include <stdio.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+#ifdef HAVE_FEENABLEEXCEPT /* from config.h, if included */
+#  include <fenv.h>
+#endif
+
+#ifndef FE_DIVBYZERO
+#  define FE_DIVBYZERO 0
+#endif
+#ifndef FE_INVALID
+#  define FE_INVALID 0
+#endif
+#ifndef FE_OVERFLOW
+#  define FE_OVERFLOW 0
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#ifdef PNG_ZLIB_HEADER
+#  include PNG_ZLIB_HEADER
+#else
+#  include <zlib.h>   /* For crc32 */
+#endif
+
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+/* pngvalid requires write support and one of the fixed or floating point APIs.
+ */
+#if defined(PNG_WRITE_SUPPORTED) &&\
+   (defined(PNG_FIXED_POINT_SUPPORTED) || defined(PNG_FLOATING_POINT_SUPPORTED))
+
+#if PNG_LIBPNG_VER < 10500
+/* This deliberately lacks the const. */
+typedef png_byte *png_const_bytep;
+
+/* This is copied from 1.5.1 png.h: */
+#define PNG_INTERLACE_ADAM7_PASSES 7
+#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
+#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
+#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
+#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
+   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
+#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
+   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
+#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
+   (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
+#define PNG_COL_FROM_PASS_COL(xIn, pass) \
+   (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
+#define PNG_PASS_MASK(pass,off) ( \
+   ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
+   ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
+#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
+   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
+#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
+   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
+
+/* These are needed too for the default build: */
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+
+/* This comes from pnglibconf.h after 1.5: */
+#define PNG_FP_1 100000
+#define PNG_GAMMA_THRESHOLD_FIXED\
+   ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
+#endif
+
+#if PNG_LIBPNG_VER < 10600
+   /* 1.6.0 constifies many APIs, the following exists to allow pngvalid to be
+    * compiled against earlier versions.
+    */
+#  define png_const_structp png_structp
+#endif
+
+#ifndef RELEASE_BUILD
+   /* RELEASE_BUILD is true for releases and release candidates: */
+#  define RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
+#endif
+#if RELEASE_BUILD
+#   define debugonly(something)
+#else /* !RELEASE_BUILD */
+#   define debugonly(something) something
+#endif /* !RELEASE_BUILD */
+
+#include <float.h>  /* For floating point constants */
+#include <stdlib.h> /* For malloc */
+#include <string.h> /* For memcpy, memset */
+#include <math.h>   /* For floor */
+
+/* Convenience macros. */
+#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
+#define CHUNK_IHDR CHUNK(73,72,68,82)
+#define CHUNK_PLTE CHUNK(80,76,84,69)
+#define CHUNK_IDAT CHUNK(73,68,65,84)
+#define CHUNK_IEND CHUNK(73,69,78,68)
+#define CHUNK_cHRM CHUNK(99,72,82,77)
+#define CHUNK_gAMA CHUNK(103,65,77,65)
+#define CHUNK_sBIT CHUNK(115,66,73,84)
+#define CHUNK_sRGB CHUNK(115,82,71,66)
+
+/* Unused formal parameter errors are removed using the following macro which is
+ * expected to have no bad effects on performance.
+ */
+#ifndef UNUSED
+#  if defined(__GNUC__) || defined(_MSC_VER)
+#     define UNUSED(param) (void)param;
+#  else
+#     define UNUSED(param)
+#  endif
+#endif
+
+/***************************** EXCEPTION HANDLING *****************************/
+#ifdef PNG_FREESTANDING_TESTS
+#  include <cexcept.h>
+#else
+#  include "../visupng/cexcept.h"
+#endif
+
+#ifdef __cplusplus
+#  define this not_the_cpp_this
+#  define new not_the_cpp_new
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+struct png_store;
+define_exception_type(struct png_store*);
+
+/* The following are macros to reduce typing everywhere where the well known
+ * name 'the_exception_context' must be defined.
+ */
+#define anon_context(ps) struct exception_context *the_exception_context = \
+   &(ps)->exception_context
+#define context(ps,fault) anon_context(ps); png_store *fault
+
+/* This macro returns the number of elements in an array as an (unsigned int),
+ * it is necessary to avoid the inability of certain versions of GCC to use
+ * the value of a compile-time constant when performing range checks.  It must
+ * be passed an array name.
+ */
+#define ARRAY_SIZE(a) ((unsigned int)((sizeof (a))/(sizeof (a)[0])))
+
+/* GCC BUG 66447 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66447) requires
+ * some broken GCC versions to be fixed up to avoid invalid whining about auto
+ * variables that are *not* changed within the scope of a setjmp being changed.
+ *
+ * Feel free to extend the list of broken versions.
+ */
+#define is_gnu(major,minor)\
+   (defined __GNUC__) && __GNUC__ == (major) && __GNUC_MINOR__ == (minor)
+#define is_gnu_patch(major,minor,patch)\
+   is_gnu(major,minor) && __GNUC_PATCHLEVEL__ == 0
+/* For the moment just do it always; all versions of GCC seem to be broken: */
+#ifdef __GNUC__
+   const void * volatile make_volatile_for_gnu;
+#  define gnu_volatile(x) make_volatile_for_gnu = &x;
+#else /* !GNUC broken versions */
+#  define gnu_volatile(x)
+#endif /* !GNUC broken versions */
+
+/******************************* UTILITIES ************************************/
+/* Error handling is particularly problematic in production code - error
+ * handlers often themselves have bugs which lead to programs that detect
+ * minor errors crashing.  The following functions deal with one very
+ * common class of errors in error handlers - attempting to format error or
+ * warning messages into buffers that are too small.
+ */
+static size_t safecat(char *buffer, size_t bufsize, size_t pos,
+   const char *cat)
+{
+   while (pos < bufsize && cat != NULL && *cat != 0)
+      buffer[pos++] = *cat++;
+
+   if (pos >= bufsize)
+      pos = bufsize-1;
+
+   buffer[pos] = 0;
+   return pos;
+}
+
+static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
+{
+   char number[64];
+   sprintf(number, "%d", n);
+   return safecat(buffer, bufsize, pos, number);
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
+    int precision)
+{
+   char number[64];
+   sprintf(number, "%.*f", precision, d);
+   return safecat(buffer, bufsize, pos, number);
+}
+#endif
+
+static const char invalid[] = "invalid";
+static const char sep[] = ": ";
+
+static const char *colour_types[8] =
+{
+   "grayscale", invalid, "truecolour", "indexed-colour",
+   "grayscale with alpha", invalid, "truecolour with alpha", invalid
+};
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Convert a double precision value to fixed point. */
+static png_fixed_point
+fix(double d)
+{
+   d = floor(d * PNG_FP_1 + .5);
+   return (png_fixed_point)d;
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* Generate random bytes.  This uses a boring repeatable algorithm and it
+ * is implemented here so that it gives the same set of numbers on every
+ * architecture.  It's a linear congruential generator (Knuth or Sedgewick
+ * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
+ * Hill, "The Art of Electronics" (Pseudo-Random Bit Sequences and Noise
+ * Generation.)
+ */
+static void
+make_random_bytes(png_uint_32* seed, void* pv, size_t size)
+{
+   png_uint_32 u0 = seed[0], u1 = seed[1];
+   png_bytep bytes = voidcast(png_bytep, pv);
+
+   /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
+    * bit-20.  The top 1 bit is in u1, the bottom 32 are in u0.
+    */
+   size_t i;
+   for (i=0; i<size; ++i)
+   {
+      /* First generate 8 new bits then shift them in at the end. */
+      png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
+      u1 <<= 8;
+      u1 |= u0 >> 24;
+      u0 <<= 8;
+      u0 |= u;
+      *bytes++ = (png_byte)u;
+   }
+
+   seed[0] = u0;
+   seed[1] = u1;
+}
+
+static void
+make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
+{
+   make_random_bytes(seed, bytes, 4);
+}
+
+#if defined PNG_READ_SUPPORTED || defined PNG_WRITE_tRNS_SUPPORTED ||\
+    defined PNG_WRITE_FILTER_SUPPORTED
+static void
+randomize(void *pv, size_t size)
+{
+   static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
+   make_random_bytes(random_seed, pv, size);
+}
+
+#define R8(this) randomize(&(this), sizeof (this))
+
+#ifdef PNG_READ_SUPPORTED
+static png_byte
+random_byte(void)
+{
+   unsigned char b1[1];
+   randomize(b1, sizeof b1);
+   return b1[0];
+}
+#endif /* READ */
+
+static png_uint_16
+random_u16(void)
+{
+   unsigned char b2[2];
+   randomize(b2, sizeof b2);
+   return png_get_uint_16(b2);
+}
+
+#if defined PNG_READ_RGB_TO_GRAY_SUPPORTED ||\
+    defined PNG_READ_FILLER_SUPPORTED
+static png_uint_32
+random_u32(void)
+{
+   unsigned char b4[4];
+   randomize(b4, sizeof b4);
+   return png_get_uint_32(b4);
+}
+#endif /* READ_FILLER || READ_RGB_TO_GRAY */
+
+#endif /* READ || WRITE_tRNS || WRITE_FILTER */
+
+#if defined PNG_READ_TRANSFORMS_SUPPORTED ||\
+    defined PNG_WRITE_FILTER_SUPPORTED
+static unsigned int
+random_mod(unsigned int max)
+{
+   return random_u16() % max; /* 0 .. max-1 */
+}
+#endif /* READ_TRANSFORMS || WRITE_FILTER */
+
+#if (defined PNG_READ_RGB_TO_GRAY_SUPPORTED) ||\
+    (defined PNG_READ_FILLER_SUPPORTED)
+static int
+random_choice(void)
+{
+   return random_byte() & 1;
+}
+#endif /* READ_RGB_TO_GRAY || READ_FILLER */
+
+/* A numeric ID based on PNG file characteristics.  The 'do_interlace' field
+ * simply records whether pngvalid did the interlace itself or whether it
+ * was done by libpng.  Width and height must be less than 256.  'palette' is an
+ * index of the palette to use for formats with a palette otherwise a boolean
+ * indicating if a tRNS chunk was generated.
+ */
+#define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
+   ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
+    (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
+
+#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
+#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
+#define PALETTE_FROM_ID(id) (((id) >> 8) & 0x1f)
+#define INTERLACE_FROM_ID(id) ((png_byte)(((id) >> 13) & 0x3))
+#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
+#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
+#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
+
+/* Utility to construct a standard name for a standard image. */
+static size_t
+standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
+    int bit_depth, unsigned int npalette, int interlace_type,
+    png_uint_32 w, png_uint_32 h, int do_interlace)
+{
+   pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
+   if (colour_type == 3) /* must have a palette */
+   {
+      pos = safecat(buffer, bufsize, pos, "[");
+      pos = safecatn(buffer, bufsize, pos, npalette);
+      pos = safecat(buffer, bufsize, pos, "]");
+   }
+
+   else if (npalette != 0)
+      pos = safecat(buffer, bufsize, pos, "+tRNS");
+
+   pos = safecat(buffer, bufsize, pos, " ");
+   pos = safecatn(buffer, bufsize, pos, bit_depth);
+   pos = safecat(buffer, bufsize, pos, " bit");
+
+   if (interlace_type != PNG_INTERLACE_NONE)
+   {
+      pos = safecat(buffer, bufsize, pos, " interlaced");
+      if (do_interlace)
+         pos = safecat(buffer, bufsize, pos, "(pngvalid)");
+      else
+         pos = safecat(buffer, bufsize, pos, "(libpng)");
+   }
+
+   if (w > 0 || h > 0)
+   {
+      pos = safecat(buffer, bufsize, pos, " ");
+      pos = safecatn(buffer, bufsize, pos, w);
+      pos = safecat(buffer, bufsize, pos, "x");
+      pos = safecatn(buffer, bufsize, pos, h);
+   }
+
+   return pos;
+}
+
+static size_t
+standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
+{
+   return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
+      DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
+      WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
+}
+
+/* Convenience API and defines to list valid formats.  Note that 16 bit read and
+ * write support is required to do 16 bit read tests (we must be able to make a
+ * 16 bit image to test!)
+ */
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+#  define WRITE_BDHI 4
+#  ifdef PNG_READ_16BIT_SUPPORTED
+#     define READ_BDHI 4
+#     define DO_16BIT
+#  endif
+#else
+#  define WRITE_BDHI 3
+#endif
+#ifndef DO_16BIT
+#  define READ_BDHI 3
+#endif
+
+/* The following defines the number of different palettes to generate for
+ * each log bit depth of a colour type 3 standard image.
+ */
+#define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1U : 16U)
+
+static int
+next_format(png_bytep colour_type, png_bytep bit_depth,
+   unsigned int* palette_number, int low_depth_gray, int tRNS)
+{
+   if (*bit_depth == 0)
+   {
+      *colour_type = 0;
+      if (low_depth_gray)
+         *bit_depth = 1;
+      else
+         *bit_depth = 8;
+      *palette_number = 0;
+      return 1;
+   }
+
+   if  (*colour_type < 4/*no alpha channel*/)
+   {
+      /* Add multiple palettes for colour type 3, one image with tRNS
+       * and one without for other non-alpha formats:
+       */
+      unsigned int pn = ++*palette_number;
+      png_byte ct = *colour_type;
+
+      if (((ct == 0/*GRAY*/ || ct/*RGB*/ == 2) && tRNS && pn < 2) ||
+          (ct == 3/*PALETTE*/ && pn < PALETTE_COUNT(*bit_depth)))
+         return 1;
+
+      /* No: next bit depth */
+      *palette_number = 0;
+   }
+
+   *bit_depth = (png_byte)(*bit_depth << 1);
+
+   /* Palette images are restricted to 8 bit depth */
+   if (*bit_depth <= 8
+#ifdef DO_16BIT
+         || (*colour_type != 3 && *bit_depth <= 16)
+#endif
+      )
+      return 1;
+
+   /* Move to the next color type, or return 0 at the end. */
+   switch (*colour_type)
+   {
+      case 0:
+         *colour_type = 2;
+         *bit_depth = 8;
+         return 1;
+
+      case 2:
+         *colour_type = 3;
+         *bit_depth = 1;
+         return 1;
+
+      case 3:
+         *colour_type = 4;
+         *bit_depth = 8;
+         return 1;
+
+      case 4:
+         *colour_type = 6;
+         *bit_depth = 8;
+         return 1;
+
+      default:
+         return 0;
+   }
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static unsigned int
+sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
+    png_uint_32 x, unsigned int sample_index, int swap16, int littleendian)
+{
+   png_uint_32 bit_index, result;
+
+   /* Find a sample index for the desired sample: */
+   x *= bit_depth;
+   bit_index = x;
+
+   if ((colour_type & 1) == 0) /* !palette */
+   {
+      if (colour_type & 2)
+         bit_index *= 3;
+
+      if (colour_type & 4)
+         bit_index += x; /* Alpha channel */
+
+      /* Multiple channels; select one: */
+      if (colour_type & (2+4))
+         bit_index += sample_index * bit_depth;
+   }
+
+   /* Return the sample from the row as an integer. */
+   row += bit_index >> 3;
+   result = *row;
+
+   if (bit_depth == 8)
+      return result;
+
+   else if (bit_depth > 8)
+   {
+      if (swap16)
+         return (*++row << 8) + result;
+      else
+         return (result << 8) + *++row;
+   }
+
+   /* Less than 8 bits per sample.  By default PNG has the big end of
+    * the egg on the left of the screen, but if littleendian is set
+    * then the big end is on the right.
+    */
+   bit_index &= 7;
+
+   if (!littleendian)
+      bit_index = 8-bit_index-bit_depth;
+
+   return (result >> bit_index) & ((1U<<bit_depth)-1);
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+/* Copy a single pixel, of a given size, from one buffer to another -
+ * while this is basically bit addressed there is an implicit assumption
+ * that pixels 8 or more bits in size are byte aligned and that pixels
+ * do not otherwise cross byte boundaries.  (This is, so far as I know,
+ * universally true in bitmap computer graphics.  [JCB 20101212])
+ *
+ * NOTE: The to and from buffers may be the same.
+ */
+static void
+pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
+   png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize,
+   int littleendian)
+{
+   /* Assume we can multiply by 'size' without overflow because we are
+    * just working in a single buffer.
+    */
+   toIndex *= pixelSize;
+   fromIndex *= pixelSize;
+   if (pixelSize < 8) /* Sub-byte */
+   {
+      /* Mask to select the location of the copied pixel: */
+      unsigned int destMask = ((1U<<pixelSize)-1) <<
+         (littleendian ? toIndex&7 : 8-pixelSize-(toIndex&7));
+      /* The following read the entire pixels and clears the extra: */
+      unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
+      unsigned int sourceByte = fromBuffer[fromIndex >> 3];
+
+      /* Don't rely on << or >> supporting '0' here, just in case: */
+      fromIndex &= 7;
+      if (littleendian)
+      {
+         if (fromIndex > 0) sourceByte >>= fromIndex;
+         if ((toIndex & 7) > 0) sourceByte <<= toIndex & 7;
+      }
+
+      else
+      {
+         if (fromIndex > 0) sourceByte <<= fromIndex;
+         if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
+      }
+
+      toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
+   }
+   else /* One or more bytes */
+      memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* Copy a complete row of pixels, taking into account potential partial
+ * bytes at the end.
+ */
+static void
+row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth,
+      int littleendian)
+{
+   memcpy(toBuffer, fromBuffer, bitWidth >> 3);
+
+   if ((bitWidth & 7) != 0)
+   {
+      unsigned int mask;
+
+      toBuffer += bitWidth >> 3;
+      fromBuffer += bitWidth >> 3;
+      if (littleendian)
+         mask = 0xff << (bitWidth & 7);
+      else
+         mask = 0xff >> (bitWidth & 7);
+      *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
+   }
+}
+
+/* Compare pixels - they are assumed to start at the first byte in the
+ * given buffers.
+ */
+static int
+pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
+{
+#if PNG_LIBPNG_VER < 10506
+   if (memcmp(pa, pb, bit_width>>3) == 0)
+   {
+      png_uint_32 p;
+
+      if ((bit_width & 7) == 0) return 0;
+
+      /* Ok, any differences? */
+      p = pa[bit_width >> 3];
+      p ^= pb[bit_width >> 3];
+
+      if (p == 0) return 0;
+
+      /* There are, but they may not be significant, remove the bits
+       * after the end (the low order bits in PNG.)
+       */
+      bit_width &= 7;
+      p >>= 8-bit_width;
+
+      if (p == 0) return 0;
+   }
+#else
+   /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
+    * bits too:
+    */
+   if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
+      return 0;
+#endif
+
+   /* Return the index of the changed byte. */
+   {
+      png_uint_32 where = 0;
+
+      while (pa[where] == pb[where]) ++where;
+      return 1+where;
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/*************************** BASIC PNG FILE WRITING ***************************/
+/* A png_store takes data from the sequential writer or provides data
+ * to the sequential reader.  It can also store the result of a PNG
+ * write for later retrieval.
+ */
+#define STORE_BUFFER_SIZE 500 /* arbitrary */
+typedef struct png_store_buffer
+{
+   struct png_store_buffer*  prev;    /* NOTE: stored in reverse order */
+   png_byte                  buffer[STORE_BUFFER_SIZE];
+} png_store_buffer;
+
+#define FILE_NAME_SIZE 64
+
+typedef struct store_palette_entry /* record of a single palette entry */
+{
+   png_byte red;
+   png_byte green;
+   png_byte blue;
+   png_byte alpha;
+} store_palette_entry, store_palette[256];
+
+typedef struct png_store_file
+{
+   struct png_store_file*  next;      /* as many as you like... */
+   char                    name[FILE_NAME_SIZE];
+   unsigned int            IDAT_bits; /* Number of bits in IDAT size */
+   png_uint_32             IDAT_size; /* Total size of IDAT data */
+   png_uint_32             id;        /* must be correct (see FILEID) */
+   size_t                  datacount; /* In this (the last) buffer */
+   png_store_buffer        data;      /* Last buffer in file */
+   int                     npalette;  /* Number of entries in palette */
+   store_palette_entry*    palette;   /* May be NULL */
+} png_store_file;
+
+/* The following is a pool of memory allocated by a single libpng read or write
+ * operation.
+ */
+typedef struct store_pool
+{
+   struct png_store    *store;   /* Back pointer */
+   struct store_memory *list;    /* List of allocated memory */
+   png_byte             mark[4]; /* Before and after data */
+
+   /* Statistics for this run. */
+   png_alloc_size_t     max;     /* Maximum single allocation */
+   png_alloc_size_t     current; /* Current allocation */
+   png_alloc_size_t     limit;   /* Highest current allocation */
+   png_alloc_size_t     total;   /* Total allocation */
+
+   /* Overall statistics (retained across successive runs). */
+   png_alloc_size_t     max_max;
+   png_alloc_size_t     max_limit;
+   png_alloc_size_t     max_total;
+} store_pool;
+
+typedef struct png_store
+{
+   /* For cexcept.h exception handling - simply store one of these;
+    * the context is a self pointer but it may point to a different
+    * png_store (in fact it never does in this program.)
+    */
+   struct exception_context
+                      exception_context;
+
+   unsigned int       verbose :1;
+   unsigned int       treat_warnings_as_errors :1;
+   unsigned int       expect_error :1;
+   unsigned int       expect_warning :1;
+   unsigned int       saw_warning :1;
+   unsigned int       speed :1;
+   unsigned int       progressive :1; /* use progressive read */
+   unsigned int       validated :1;   /* used as a temporary flag */
+   int                nerrors;
+   int                nwarnings;
+   int                noptions;       /* number of options below: */
+   struct {
+      unsigned char   option;         /* option number, 0..30 */
+      unsigned char   setting;        /* setting (unset,invalid,on,off) */
+   }                  options[16];
+   char               test[128];      /* Name of test */
+   char               error[256];
+
+   /* Share fields */
+   png_uint_32        chunklen; /* Length of chunk+overhead (chunkpos >= 8) */
+   png_uint_32        chunktype;/* Type of chunk (valid if chunkpos >= 4) */
+   png_uint_32        chunkpos; /* Position in chunk */
+   png_uint_32        IDAT_size;/* Accumulated IDAT size in .new */
+   unsigned int       IDAT_bits;/* Cache of the file store value */
+
+   /* Read fields */
+   png_structp        pread;    /* Used to read a saved file */
+   png_infop          piread;
+   png_store_file*    current;  /* Set when reading */
+   png_store_buffer*  next;     /* Set when reading */
+   size_t             readpos;  /* Position in *next */
+   png_byte*          image;    /* Buffer for reading interlaced images */
+   size_t             cb_image; /* Size of this buffer */
+   size_t             cb_row;   /* Row size of the image(s) */
+   uLong              IDAT_crc;
+   png_uint_32        IDAT_len; /* Used when re-chunking IDAT chunks */
+   png_uint_32        IDAT_pos; /* Used when re-chunking IDAT chunks */
+   png_uint_32        image_h;  /* Number of rows in a single image */
+   store_pool         read_memory_pool;
+
+   /* Write fields */
+   png_store_file*    saved;
+   png_structp        pwrite;   /* Used when writing a new file */
+   png_infop          piwrite;
+   size_t             writepos; /* Position in .new */
+   char               wname[FILE_NAME_SIZE];
+   png_store_buffer   new;      /* The end of the new PNG file being written. */
+   store_pool         write_memory_pool;
+   store_palette_entry* palette;
+   int                  npalette;
+} png_store;
+
+/* Initialization and cleanup */
+static void
+store_pool_mark(png_bytep mark)
+{
+   static png_uint_32 store_seed[2] = { 0x12345678, 1};
+
+   make_four_random_bytes(store_seed, mark);
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Use this for random 32 bit values; this function makes sure the result is
+ * non-zero.
+ */
+static png_uint_32
+random_32(void)
+{
+
+   for (;;)
+   {
+      png_byte mark[4];
+      png_uint_32 result;
+
+      store_pool_mark(mark);
+      result = png_get_uint_32(mark);
+
+      if (result != 0)
+         return result;
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+static void
+store_pool_init(png_store *ps, store_pool *pool)
+{
+   memset(pool, 0, sizeof *pool);
+
+   pool->store = ps;
+   pool->list = NULL;
+   pool->max = pool->current = pool->limit = pool->total = 0;
+   pool->max_max = pool->max_limit = pool->max_total = 0;
+   store_pool_mark(pool->mark);
+}
+
+static void
+store_init(png_store* ps)
+{
+   memset(ps, 0, sizeof *ps);
+   init_exception_context(&ps->exception_context);
+   store_pool_init(ps, &ps->read_memory_pool);
+   store_pool_init(ps, &ps->write_memory_pool);
+   ps->verbose = 0;
+   ps->treat_warnings_as_errors = 0;
+   ps->expect_error = 0;
+   ps->expect_warning = 0;
+   ps->saw_warning = 0;
+   ps->speed = 0;
+   ps->progressive = 0;
+   ps->validated = 0;
+   ps->nerrors = ps->nwarnings = 0;
+   ps->pread = NULL;
+   ps->piread = NULL;
+   ps->saved = ps->current = NULL;
+   ps->next = NULL;
+   ps->readpos = 0;
+   ps->image = NULL;
+   ps->cb_image = 0;
+   ps->cb_row = 0;
+   ps->image_h = 0;
+   ps->pwrite = NULL;
+   ps->piwrite = NULL;
+   ps->writepos = 0;
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+   ps->IDAT_bits = 0;
+   ps->new.prev = NULL;
+   ps->palette = NULL;
+   ps->npalette = 0;
+   ps->noptions = 0;
+}
+
+static void
+store_freebuffer(png_store_buffer* psb)
+{
+   if (psb->prev)
+   {
+      store_freebuffer(psb->prev);
+      free(psb->prev);
+      psb->prev = NULL;
+   }
+}
+
+static void
+store_freenew(png_store *ps)
+{
+   store_freebuffer(&ps->new);
+   ps->writepos = 0;
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+   ps->IDAT_bits = 0;
+   if (ps->palette != NULL)
+   {
+      free(ps->palette);
+      ps->palette = NULL;
+      ps->npalette = 0;
+   }
+}
+
+static void
+store_storenew(png_store *ps)
+{
+   png_store_buffer *pb;
+
+   pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
+
+   if (pb == NULL)
+      png_error(ps->pwrite, "store new: OOM");
+
+   *pb = ps->new;
+   ps->new.prev = pb;
+   ps->writepos = 0;
+}
+
+static void
+store_freefile(png_store_file **ppf)
+{
+   if (*ppf != NULL)
+   {
+      store_freefile(&(*ppf)->next);
+
+      store_freebuffer(&(*ppf)->data);
+      (*ppf)->datacount = 0;
+      if ((*ppf)->palette != NULL)
+      {
+         free((*ppf)->palette);
+         (*ppf)->palette = NULL;
+         (*ppf)->npalette = 0;
+      }
+      free(*ppf);
+      *ppf = NULL;
+   }
+}
+
+static unsigned int
+bits_of(png_uint_32 num)
+{
+   /* Return the number of bits in 'num' */
+   unsigned int b = 0;
+
+   if (num & 0xffff0000U)  b += 16U, num >>= 16;
+   if (num & 0xff00U)      b += 8U, num >>= 8;
+   if (num & 0xf0U)        b += 4U, num >>= 4;
+   if (num & 0xcU)         b += 2U, num >>= 2;
+   if (num & 0x2U)         ++b, num >>= 1;
+   if (num)                ++b;
+
+   return b; /* 0..32 */
+}
+
+/* Main interface to file storage, after writing a new PNG file (see the API
+ * below) call store_storefile to store the result with the given name and id.
+ */
+static void
+store_storefile(png_store *ps, png_uint_32 id)
+{
+   png_store_file *pf;
+
+   if (ps->chunkpos != 0U || ps->chunktype != 0U || ps->chunklen != 0U ||
+       ps->IDAT_size == 0)
+      png_error(ps->pwrite, "storefile: incomplete write");
+
+   pf = voidcast(png_store_file*, malloc(sizeof *pf));
+   if (pf == NULL)
+      png_error(ps->pwrite, "storefile: OOM");
+   safecat(pf->name, sizeof pf->name, 0, ps->wname);
+   pf->id = id;
+   pf->data = ps->new;
+   pf->datacount = ps->writepos;
+   pf->IDAT_size = ps->IDAT_size;
+   pf->IDAT_bits = bits_of(ps->IDAT_size);
+   /* Because the IDAT always has zlib header stuff this must be true: */
+   if (pf->IDAT_bits == 0U)
+      png_error(ps->pwrite, "storefile: 0 sized IDAT");
+   ps->new.prev = NULL;
+   ps->writepos = 0;
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+   pf->palette = ps->palette;
+   pf->npalette = ps->npalette;
+   ps->palette = 0;
+   ps->npalette = 0;
+
+   /* And save it. */
+   pf->next = ps->saved;
+   ps->saved = pf;
+}
+
+/* Generate an error message (in the given buffer) */
+static size_t
+store_message(png_store *ps, png_const_structp pp, char *buffer, size_t bufsize,
+   size_t pos, const char *msg)
+{
+   if (pp != NULL && pp == ps->pread)
+   {
+      /* Reading a file */
+      pos = safecat(buffer, bufsize, pos, "read: ");
+
+      if (ps->current != NULL)
+      {
+         pos = safecat(buffer, bufsize, pos, ps->current->name);
+         pos = safecat(buffer, bufsize, pos, sep);
+      }
+   }
+
+   else if (pp != NULL && pp == ps->pwrite)
+   {
+      /* Writing a file */
+      pos = safecat(buffer, bufsize, pos, "write: ");
+      pos = safecat(buffer, bufsize, pos, ps->wname);
+      pos = safecat(buffer, bufsize, pos, sep);
+   }
+
+   else
+   {
+      /* Neither reading nor writing (or a memory error in struct delete) */
+      pos = safecat(buffer, bufsize, pos, "pngvalid: ");
+   }
+
+   if (ps->test[0] != 0)
+   {
+      pos = safecat(buffer, bufsize, pos, ps->test);
+      pos = safecat(buffer, bufsize, pos, sep);
+   }
+   pos = safecat(buffer, bufsize, pos, msg);
+   return pos;
+}
+
+/* Verbose output to the error stream: */
+static void
+store_verbose(png_store *ps, png_const_structp pp, png_const_charp prefix,
+   png_const_charp message)
+{
+   char buffer[512];
+
+   if (prefix)
+      fputs(prefix, stderr);
+
+   (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
+   fputs(buffer, stderr);
+   fputc('\n', stderr);
+}
+
+/* Log an error or warning - the relevant count is always incremented. */
+static void
+store_log(png_store* ps, png_const_structp pp, png_const_charp message,
+   int is_error)
+{
+   /* The warning is copied to the error buffer if there are no errors and it is
+    * the first warning.  The error is copied to the error buffer if it is the
+    * first error (overwriting any prior warnings).
+    */
+   if (is_error ? (ps->nerrors)++ == 0 :
+       (ps->nwarnings)++ == 0 && ps->nerrors == 0)
+      store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
+
+   if (ps->verbose)
+      store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* Internal error function, called with a png_store but no libpng stuff. */
+static void
+internal_error(png_store *ps, png_const_charp message)
+{
+   store_log(ps, NULL, message, 1 /* error */);
+
+   /* And finally throw an exception. */
+   {
+      struct exception_context *the_exception_context = &ps->exception_context;
+      Throw ps;
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* Functions to use as PNG callbacks. */
+static void PNGCBAPI
+store_error(png_structp ppIn, png_const_charp message) /* PNG_NORETURN */
+{
+   png_const_structp pp = ppIn;
+   png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
+
+   if (!ps->expect_error)
+      store_log(ps, pp, message, 1 /* error */);
+
+   /* And finally throw an exception. */
+   {
+      struct exception_context *the_exception_context = &ps->exception_context;
+      Throw ps;
+   }
+}
+
+static void PNGCBAPI
+store_warning(png_structp ppIn, png_const_charp message)
+{
+   png_const_structp pp = ppIn;
+   png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
+
+   if (!ps->expect_warning)
+      store_log(ps, pp, message, 0 /* warning */);
+   else
+      ps->saw_warning = 1;
+}
+
+/* These somewhat odd functions are used when reading an image to ensure that
+ * the buffer is big enough, the png_structp is for errors.
+ */
+/* Return a single row from the correct image. */
+static png_bytep
+store_image_row(const png_store* ps, png_const_structp pp, int nImage,
+   png_uint_32 y)
+{
+   size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
+
+   if (ps->image == NULL)
+      png_error(pp, "no allocated image");
+
+   if (coffset + ps->cb_row + 3 > ps->cb_image)
+      png_error(pp, "image too small");
+
+   return ps->image + coffset;
+}
+
+static void
+store_image_free(png_store *ps, png_const_structp pp)
+{
+   if (ps->image != NULL)
+   {
+      png_bytep image = ps->image;
+
+      if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
+      {
+         if (pp != NULL)
+            png_error(pp, "png_store image overwrite (1)");
+         else
+            store_log(ps, NULL, "png_store image overwrite (2)", 1);
+      }
+
+      ps->image = NULL;
+      ps->cb_image = 0;
+      --image;
+      free(image);
+   }
+}
+
+static void
+store_ensure_image(png_store *ps, png_const_structp pp, int nImages,
+   size_t cbRow, png_uint_32 cRows)
+{
+   size_t cb = nImages * cRows * (cbRow + 5);
+
+   if (ps->cb_image < cb)
+   {
+      png_bytep image;
+
+      store_image_free(ps, pp);
+
+      /* The buffer is deliberately mis-aligned. */
+      image = voidcast(png_bytep, malloc(cb+2));
+      if (image == NULL)
+      {
+         /* Called from the startup - ignore the error for the moment. */
+         if (pp == NULL)
+            return;
+
+         png_error(pp, "OOM allocating image buffer");
+      }
+
+      /* These magic tags are used to detect overwrites above. */
+      ++image;
+      image[-1] = 0xed;
+      image[cb] = 0xfe;
+
+      ps->image = image;
+      ps->cb_image = cb;
+   }
+
+   /* We have an adequate sized image; lay out the rows.  There are 2 bytes at
+    * the start and three at the end of each (this ensures that the row
+    * alignment starts out odd - 2+1 and changes for larger images on each row.)
+    */
+   ps->cb_row = cbRow;
+   ps->image_h = cRows;
+
+   /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
+    * This deliberately doesn't match the bits in the size test image which are
+    * outside the image; these are set to 0xff (all 1).  To make the row
+    * comparison work in the 'size' test case the size rows are pre-initialized
+    * to the same value prior to calling 'standard_row'.
+    */
+   memset(ps->image, 178, cb);
+
+   /* Then put in the marks. */
+   while (--nImages >= 0)
+   {
+      png_uint_32 y;
+
+      for (y=0; y<cRows; ++y)
+      {
+         png_bytep row = store_image_row(ps, pp, nImages, y);
+
+         /* The markers: */
+         row[-2] = 190;
+         row[-1] = 239;
+         row[cbRow] = 222;
+         row[cbRow+1] = 173;
+         row[cbRow+2] = 17;
+      }
+   }
+}
+
+#ifdef PNG_READ_SUPPORTED
+static void
+store_image_check(const png_store* ps, png_const_structp pp, int iImage)
+{
+   png_const_bytep image = ps->image;
+
+   if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
+      png_error(pp, "image overwrite");
+   else
+   {
+      size_t cbRow = ps->cb_row;
+      png_uint_32 rows = ps->image_h;
+
+      image += iImage * (cbRow+5) * ps->image_h;
+
+      image += 2; /* skip image first row markers */
+
+      for (; rows > 0; --rows)
+      {
+         if (image[-2] != 190 || image[-1] != 239)
+            png_error(pp, "row start overwritten");
+
+         if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
+            image[cbRow+2] != 17)
+            png_error(pp, "row end overwritten");
+
+         image += cbRow+5;
+      }
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+static int
+valid_chunktype(png_uint_32 chunktype)
+{
+   /* Each byte in the chunk type must be in one of the ranges 65..90, 97..122
+    * (both inclusive), so:
+    */
+   unsigned int i;
+
+   for (i=0; i<4; ++i)
+   {
+      unsigned int c = chunktype & 0xffU;
+
+      if (!((c >= 65U && c <= 90U) || (c >= 97U && c <= 122U)))
+         return 0;
+
+      chunktype >>= 8;
+   }
+
+   return 1; /* It's valid */
+}
+
+static void PNGCBAPI
+store_write(png_structp ppIn, png_bytep pb, size_t st)
+{
+   png_const_structp pp = ppIn;
+   png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
+   size_t writepos = ps->writepos;
+   png_uint_32 chunkpos = ps->chunkpos;
+   png_uint_32 chunktype = ps->chunktype;
+   png_uint_32 chunklen = ps->chunklen;
+
+   if (ps->pwrite != pp)
+      png_error(pp, "store state damaged");
+
+   /* Technically this is legal, but in practice libpng never writes more than
+    * the maximum chunk size at once so if it happens something weird has
+    * changed inside libpng (probably).
+    */
+   if (st > 0x7fffffffU)
+      png_error(pp, "unexpected write size");
+
+   /* Now process the bytes to be written.  Do this in units of the space in the
+    * output (write) buffer or, at the start 4 bytes for the chunk type and
+    * length limited in any case by the amount of data.
+    */
+   while (st > 0)
+   {
+      if (writepos >= STORE_BUFFER_SIZE)
+         store_storenew(ps), writepos = 0;
+
+      if (chunkpos < 4)
+      {
+         png_byte b = *pb++;
+         --st;
+         chunklen = (chunklen << 8) + b;
+         ps->new.buffer[writepos++] = b;
+         ++chunkpos;
+      }
+
+      else if (chunkpos < 8)
+      {
+         png_byte b = *pb++;
+         --st;
+         chunktype = (chunktype << 8) + b;
+         ps->new.buffer[writepos++] = b;
+
+         if (++chunkpos == 8)
+         {
+            chunklen &= 0xffffffffU;
+            if (chunklen > 0x7fffffffU)
+               png_error(pp, "chunk length too great");
+
+            chunktype &= 0xffffffffU;
+            if (chunktype == CHUNK_IDAT)
+            {
+               if (chunklen > ~ps->IDAT_size)
+                  png_error(pp, "pngvalid internal image too large");
+
+               ps->IDAT_size += chunklen;
+            }
+
+            else if (!valid_chunktype(chunktype))
+               png_error(pp, "invalid chunk type");
+
+            chunklen += 12; /* for header and CRC */
+         }
+      }
+
+      else /* chunkpos >= 8 */
+      {
+         size_t cb = st;
+
+         if (cb > STORE_BUFFER_SIZE - writepos)
+            cb = STORE_BUFFER_SIZE - writepos;
+
+         if (cb  > chunklen - chunkpos/* bytes left in chunk*/)
+            cb = (size_t)/*SAFE*/(chunklen - chunkpos);
+
+         memcpy(ps->new.buffer + writepos, pb, cb);
+         chunkpos += (png_uint_32)/*SAFE*/cb;
+         pb += cb;
+         writepos += cb;
+         st -= cb;
+
+         if (chunkpos >= chunklen) /* must be equal */
+            chunkpos = chunktype = chunklen = 0;
+      }
+   } /* while (st > 0) */
+
+   ps->writepos = writepos;
+   ps->chunkpos = chunkpos;
+   ps->chunktype = chunktype;
+   ps->chunklen = chunklen;
+}
+
+static void PNGCBAPI
+store_flush(png_structp ppIn)
+{
+   UNUSED(ppIn) /*DOES NOTHING*/
+}
+
+#ifdef PNG_READ_SUPPORTED
+static size_t
+store_read_buffer_size(png_store *ps)
+{
+   /* Return the bytes available for read in the current buffer. */
+   if (ps->next != &ps->current->data)
+      return STORE_BUFFER_SIZE;
+
+   return ps->current->datacount;
+}
+
+/* Return total bytes available for read. */
+static size_t
+store_read_buffer_avail(png_store *ps)
+{
+   if (ps->current != NULL && ps->next != NULL)
+   {
+      png_store_buffer *next = &ps->current->data;
+      size_t cbAvail = ps->current->datacount;
+
+      while (next != ps->next && next != NULL)
+      {
+         next = next->prev;
+         cbAvail += STORE_BUFFER_SIZE;
+      }
+
+      if (next != ps->next)
+         png_error(ps->pread, "buffer read error");
+
+      if (cbAvail > ps->readpos)
+         return cbAvail - ps->readpos;
+   }
+
+   return 0;
+}
+
+static int
+store_read_buffer_next(png_store *ps)
+{
+   png_store_buffer *pbOld = ps->next;
+   png_store_buffer *pbNew = &ps->current->data;
+   if (pbOld != pbNew)
+   {
+      while (pbNew != NULL && pbNew->prev != pbOld)
+         pbNew = pbNew->prev;
+
+      if (pbNew != NULL)
+      {
+         ps->next = pbNew;
+         ps->readpos = 0;
+         return 1;
+      }
+
+      png_error(ps->pread, "buffer lost");
+   }
+
+   return 0; /* EOF or error */
+}
+
+/* Need separate implementation and callback to allow use of the same code
+ * during progressive read, where the io_ptr is set internally by libpng.
+ */
+static void
+store_read_imp(png_store *ps, png_bytep pb, size_t st)
+{
+   if (ps->current == NULL || ps->next == NULL)
+      png_error(ps->pread, "store state damaged");
+
+   while (st > 0)
+   {
+      size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
+
+      if (cbAvail > 0)
+      {
+         if (cbAvail > st) cbAvail = st;
+         memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
+         st -= cbAvail;
+         pb += cbAvail;
+         ps->readpos += cbAvail;
+      }
+
+      else if (!store_read_buffer_next(ps))
+         png_error(ps->pread, "read beyond end of file");
+   }
+}
+
+static size_t
+store_read_chunk(png_store *ps, png_bytep pb, size_t max, size_t min)
+{
+   png_uint_32 chunklen = ps->chunklen;
+   png_uint_32 chunktype = ps->chunktype;
+   png_uint_32 chunkpos = ps->chunkpos;
+   size_t st = max;
+
+   if (st > 0) do
+   {
+      if (chunkpos >= chunklen) /* end of last chunk */
+      {
+         png_byte buffer[8];
+
+         /* Read the header of the next chunk: */
+         store_read_imp(ps, buffer, 8U);
+         chunklen = png_get_uint_32(buffer) + 12U;
+         chunktype = png_get_uint_32(buffer+4U);
+         chunkpos = 0U; /* Position read so far */
+      }
+
+      if (chunktype == CHUNK_IDAT)
+      {
+         png_uint_32 IDAT_pos = ps->IDAT_pos;
+         png_uint_32 IDAT_len = ps->IDAT_len;
+         png_uint_32 IDAT_size = ps->IDAT_size;
+
+         /* The IDAT headers are constructed here; skip the input header. */
+         if (chunkpos < 8U)
+            chunkpos = 8U;
+
+         if (IDAT_pos == IDAT_len)
+         {
+            png_byte random = random_byte();
+
+            /* Make a new IDAT chunk, if IDAT_len is 0 this is the first IDAT,
+             * if IDAT_size is 0 this is the end.  At present this is set up
+             * using a random number so that there is a 25% chance before
+             * the start of the first IDAT chunk being 0 length.
+             */
+            if (IDAT_len == 0U) /* First IDAT */
+            {
+               switch (random & 3U)
+               {
+                  case 0U: IDAT_len = 12U; break; /* 0 bytes */
+                  case 1U: IDAT_len = 13U; break; /* 1 byte */
+                  default: IDAT_len = random_u32();
+                           IDAT_len %= IDAT_size;
+                           IDAT_len += 13U; /* 1..IDAT_size bytes */
+                           break;
+               }
+            }
+
+            else if (IDAT_size == 0U) /* all IDAT data read */
+            {
+               /* The last (IDAT) chunk should be positioned at the CRC now: */
+               if (chunkpos != chunklen-4U)
+                  png_error(ps->pread, "internal: IDAT size mismatch");
+
+               /* The only option here is to add a zero length IDAT, this
+                * happens 25% of the time.  Because of the check above
+                * chunklen-4U-chunkpos must be zero, we just need to skip the
+                * CRC now.
+                */
+               if ((random & 3U) == 0U)
+                  IDAT_len = 12U; /* Output another 0 length IDAT */
+
+               else
+               {
+                  /* End of IDATs, skip the CRC to make the code above load the
+                   * next chunk header next time round.
+                   */
+                  png_byte buffer[4];
+
+                  store_read_imp(ps, buffer, 4U);
+                  chunkpos += 4U;
+                  ps->IDAT_pos = IDAT_pos;
+                  ps->IDAT_len = IDAT_len;
+                  ps->IDAT_size = 0U;
+                  continue; /* Read the next chunk */
+               }
+            }
+
+            else
+            {
+               /* Middle of IDATs, use 'random' to determine the number of bits
+                * to use in the IDAT length.
+                */
+               IDAT_len = random_u32();
+               IDAT_len &= (1U << (1U + random % ps->IDAT_bits)) - 1U;
+               if (IDAT_len > IDAT_size)
+                  IDAT_len = IDAT_size;
+               IDAT_len += 12U; /* zero bytes may occur */
+            }
+
+            IDAT_pos = 0U;
+            ps->IDAT_crc = 0x35af061e; /* Ie: crc32(0UL, "IDAT", 4) */
+         } /* IDAT_pos == IDAT_len */
+
+         if (IDAT_pos < 8U) /* Return the header */ do
+         {
+            png_uint_32 b;
+            unsigned int shift;
+
+            if (IDAT_pos < 4U)
+               b = IDAT_len - 12U;
+
+            else
+               b = CHUNK_IDAT;
+
+            shift = 3U & IDAT_pos;
+            ++IDAT_pos;
+
+            if (shift < 3U)
+               b >>= 8U*(3U-shift);
+
+            *pb++ = 0xffU & b;
+         }
+         while (--st > 0 && IDAT_pos < 8);
+
+         else if (IDAT_pos < IDAT_len - 4U) /* I.e not the CRC */
+         {
+            if (chunkpos < chunklen-4U)
+            {
+               uInt avail = (uInt)-1;
+
+               if (avail > (IDAT_len-4U) - IDAT_pos)
+                  avail = (uInt)/*SAFE*/((IDAT_len-4U) - IDAT_pos);
+
+               if (avail > st)
+                  avail = (uInt)/*SAFE*/st;
+
+               if (avail > (chunklen-4U) - chunkpos)
+                  avail = (uInt)/*SAFE*/((chunklen-4U) - chunkpos);
+
+               store_read_imp(ps, pb, avail);
+               ps->IDAT_crc = crc32(ps->IDAT_crc, pb, avail);
+               pb += (size_t)/*SAFE*/avail;
+               st -= (size_t)/*SAFE*/avail;
+               chunkpos += (png_uint_32)/*SAFE*/avail;
+               IDAT_size -= (png_uint_32)/*SAFE*/avail;
+               IDAT_pos += (png_uint_32)/*SAFE*/avail;
+            }
+
+            else /* skip the input CRC */
+            {
+               png_byte buffer[4];
+
+               store_read_imp(ps, buffer, 4U);
+               chunkpos += 4U;
+            }
+         }
+
+         else /* IDAT crc */ do
+         {
+            uLong b = ps->IDAT_crc;
+            unsigned int shift = (IDAT_len - IDAT_pos); /* 4..1 */
+            ++IDAT_pos;
+
+            if (shift > 1U)
+               b >>= 8U*(shift-1U);
+
+            *pb++ = 0xffU & b;
+         }
+         while (--st > 0 && IDAT_pos < IDAT_len);
+
+         ps->IDAT_pos = IDAT_pos;
+         ps->IDAT_len = IDAT_len;
+         ps->IDAT_size = IDAT_size;
+      }
+
+      else /* !IDAT */
+      {
+         /* If there is still some pending IDAT data after the IDAT chunks have
+          * been processed there is a problem:
+          */
+         if (ps->IDAT_len > 0 && ps->IDAT_size > 0)
+            png_error(ps->pread, "internal: missing IDAT data");
+
+         if (chunktype == CHUNK_IEND && ps->IDAT_len == 0U)
+            png_error(ps->pread, "internal: missing IDAT");
+
+         if (chunkpos < 8U) /* Return the header */ do
+         {
+            png_uint_32 b;
+            unsigned int shift;
+
+            if (chunkpos < 4U)
+               b = chunklen - 12U;
+
+            else
+               b = chunktype;
+
+            shift = 3U & chunkpos;
+            ++chunkpos;
+
+            if (shift < 3U)
+               b >>= 8U*(3U-shift);
+
+            *pb++ = 0xffU & b;
+         }
+         while (--st > 0 && chunkpos < 8);
+
+         else /* Return chunk bytes, including the CRC */
+         {
+            size_t avail = st;
+
+            if (avail > chunklen - chunkpos)
+               avail = (size_t)/*SAFE*/(chunklen - chunkpos);
+
+            store_read_imp(ps, pb, avail);
+            pb += avail;
+            st -= avail;
+            chunkpos += (png_uint_32)/*SAFE*/avail;
+
+            /* Check for end of chunk and end-of-file; don't try to read a new
+             * chunk header at this point unless instructed to do so by 'min'.
+             */
+            if (chunkpos >= chunklen && max-st >= min &&
+                     store_read_buffer_avail(ps) == 0)
+               break;
+         }
+      } /* !IDAT */
+   }
+   while (st > 0);
+
+   ps->chunklen = chunklen;
+   ps->chunktype = chunktype;
+   ps->chunkpos = chunkpos;
+
+   return st; /* space left */
+}
+
+static void PNGCBAPI
+store_read(png_structp ppIn, png_bytep pb, size_t st)
+{
+   png_const_structp pp = ppIn;
+   png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
+
+   if (ps == NULL || ps->pread != pp)
+      png_error(pp, "bad store read call");
+
+   store_read_chunk(ps, pb, st, st);
+}
+
+static void
+store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
+{
+   if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
+      png_error(pp, "store state damaged (progressive)");
+
+   /* This is another Horowitz and Hill random noise generator.  In this case
+    * the aim is to stress the progressive reader with truly horrible variable
+    * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
+    * is generated.  We could probably just count from 1 to 32767 and get as
+    * good a result.
+    */
+   while (store_read_buffer_avail(ps) > 0)
+   {
+      static png_uint_32 noise = 2;
+      size_t cb;
+      png_byte buffer[512];
+
+      /* Generate 15 more bits of stuff: */
+      noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
+      cb = noise & 0x1ff;
+      cb -= store_read_chunk(ps, buffer, cb, 1);
+      png_process_data(pp, pi, buffer, cb);
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* The caller must fill this in: */
+static store_palette_entry *
+store_write_palette(png_store *ps, int npalette)
+{
+   if (ps->pwrite == NULL)
+      store_log(ps, NULL, "attempt to write palette without write stream", 1);
+
+   if (ps->palette != NULL)
+      png_error(ps->pwrite, "multiple store_write_palette calls");
+
+   /* This function can only return NULL if called with '0'! */
+   if (npalette > 0)
+   {
+      ps->palette = voidcast(store_palette_entry*, malloc(npalette *
+         sizeof *ps->palette));
+
+      if (ps->palette == NULL)
+         png_error(ps->pwrite, "store new palette: OOM");
+
+      ps->npalette = npalette;
+   }
+
+   return ps->palette;
+}
+
+#ifdef PNG_READ_SUPPORTED
+static store_palette_entry *
+store_current_palette(png_store *ps, int *npalette)
+{
+   /* This is an internal error (the call has been made outside a read
+    * operation.)
+    */
+   if (ps->current == NULL)
+   {
+      store_log(ps, ps->pread, "no current stream for palette", 1);
+      return NULL;
+   }
+
+   /* The result may be null if there is no palette. */
+   *npalette = ps->current->npalette;
+   return ps->current->palette;
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/***************************** MEMORY MANAGEMENT*** ***************************/
+#ifdef PNG_USER_MEM_SUPPORTED
+/* A store_memory is simply the header for an allocated block of memory.  The
+ * pointer returned to libpng is just after the end of the header block, the
+ * allocated memory is followed by a second copy of the 'mark'.
+ */
+typedef struct store_memory
+{
+   store_pool          *pool;    /* Originating pool */
+   struct store_memory *next;    /* Singly linked list */
+   png_alloc_size_t     size;    /* Size of memory allocated */
+   png_byte             mark[4]; /* ID marker */
+} store_memory;
+
+/* Handle a fatal error in memory allocation.  This calls png_error if the
+ * libpng struct is non-NULL, else it outputs a message and returns.  This means
+ * that a memory problem while libpng is running will abort (png_error) the
+ * handling of particular file while one in cleanup (after the destroy of the
+ * struct has returned) will simply keep going and free (or attempt to free)
+ * all the memory.
+ */
+static void
+store_pool_error(png_store *ps, png_const_structp pp, const char *msg)
+{
+   if (pp != NULL)
+      png_error(pp, msg);
+
+   /* Else we have to do it ourselves.  png_error eventually calls store_log,
+    * above.  store_log accepts a NULL png_structp - it just changes what gets
+    * output by store_message.
+    */
+   store_log(ps, pp, msg, 1 /* error */);
+}
+
+static void
+store_memory_free(png_const_structp pp, store_pool *pool, store_memory *memory)
+{
+   /* Note that pp may be NULL (see store_pool_delete below), the caller has
+    * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
+    * pointer (for sure), but the contents may have been trashed.
+    */
+   if (memory->pool != pool)
+      store_pool_error(pool->store, pp, "memory corrupted (pool)");
+
+   else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
+      store_pool_error(pool->store, pp, "memory corrupted (start)");
+
+   /* It should be safe to read the size field now. */
+   else
+   {
+      png_alloc_size_t cb = memory->size;
+
+      if (cb > pool->max)
+         store_pool_error(pool->store, pp, "memory corrupted (size)");
+
+      else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
+         != 0)
+         store_pool_error(pool->store, pp, "memory corrupted (end)");
+
+      /* Finally give the library a chance to find problems too: */
+      else
+         {
+         pool->current -= cb;
+         free(memory);
+         }
+   }
+}
+
+static void
+store_pool_delete(png_store *ps, store_pool *pool)
+{
+   if (pool->list != NULL)
+   {
+      fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
+         pool == &ps->read_memory_pool ? "read" : "write",
+         pool == &ps->read_memory_pool ? (ps->current != NULL ?
+            ps->current->name : "unknown file") : ps->wname);
+      ++ps->nerrors;
+
+      do
+      {
+         store_memory *next = pool->list;
+         pool->list = next->next;
+         next->next = NULL;
+
+         fprintf(stderr, "\t%lu bytes @ %p\n",
+             (unsigned long)next->size, (const void*)(next+1));
+         /* The NULL means this will always return, even if the memory is
+          * corrupted.
+          */
+         store_memory_free(NULL, pool, next);
+      }
+      while (pool->list != NULL);
+   }
+
+   /* And reset the other fields too for the next time. */
+   if (pool->max > pool->max_max) pool->max_max = pool->max;
+   pool->max = 0;
+   if (pool->current != 0) /* unexpected internal error */
+      fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
+         ps->test, pool == &ps->read_memory_pool ? "read" : "write",
+         pool == &ps->read_memory_pool ? (ps->current != NULL ?
+            ps->current->name : "unknown file") : ps->wname);
+   pool->current = 0;
+
+   if (pool->limit > pool->max_limit)
+      pool->max_limit = pool->limit;
+
+   pool->limit = 0;
+
+   if (pool->total > pool->max_total)
+      pool->max_total = pool->total;
+
+   pool->total = 0;
+
+   /* Get a new mark too. */
+   store_pool_mark(pool->mark);
+}
+
+/* The memory callbacks: */
+static png_voidp PNGCBAPI
+store_malloc(png_structp ppIn, png_alloc_size_t cb)
+{
+   png_const_structp pp = ppIn;
+   store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
+   store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
+      (sizeof pool->mark)));
+
+   if (new != NULL)
+   {
+      if (cb > pool->max)
+         pool->max = cb;
+
+      pool->current += cb;
+
+      if (pool->current > pool->limit)
+         pool->limit = pool->current;
+
+      pool->total += cb;
+
+      new->size = cb;
+      memcpy(new->mark, pool->mark, sizeof new->mark);
+      memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
+      new->pool = pool;
+      new->next = pool->list;
+      pool->list = new;
+      ++new;
+   }
+
+   else
+   {
+      /* NOTE: the PNG user malloc function cannot use the png_ptr it is passed
+       * other than to retrieve the allocation pointer!  libpng calls the
+       * store_malloc callback in two basic cases:
+       *
+       * 1) From png_malloc; png_malloc will do a png_error itself if NULL is
+       *    returned.
+       * 2) From png_struct or png_info structure creation; png_malloc is
+       *    to return so cleanup can be performed.
+       *
+       * To handle this store_malloc can log a message, but can't do anything
+       * else.
+       */
+      store_log(pool->store, pp, "out of memory", 1 /* is_error */);
+   }
+
+   return new;
+}
+
+static void PNGCBAPI
+store_free(png_structp ppIn, png_voidp memory)
+{
+   png_const_structp pp = ppIn;
+   store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
+   store_memory *this = voidcast(store_memory*, memory), **test;
+
+   /* Because libpng calls store_free with a dummy png_struct when deleting
+    * png_struct or png_info via png_destroy_struct_2 it is necessary to check
+    * the passed in png_structp to ensure it is valid, and not pass it to
+    * png_error if it is not.
+    */
+   if (pp != pool->store->pread && pp != pool->store->pwrite)
+      pp = NULL;
+
+   /* First check that this 'memory' really is valid memory - it must be in the
+    * pool list.  If it is, use the shared memory_free function to free it.
+    */
+   --this;
+   for (test = &pool->list; *test != this; test = &(*test)->next)
+   {
+      if (*test == NULL)
+      {
+         store_pool_error(pool->store, pp, "bad pointer to free");
+         return;
+      }
+   }
+
+   /* Unlink this entry, *test == this. */
+   *test = this->next;
+   this->next = NULL;
+   store_memory_free(pp, pool, this);
+}
+#endif /* PNG_USER_MEM_SUPPORTED */
+
+/* Setup functions. */
+/* Cleanup when aborting a write or after storing the new file. */
+static void
+store_write_reset(png_store *ps)
+{
+   if (ps->pwrite != NULL)
+   {
+      anon_context(ps);
+
+      Try
+         png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
+
+      Catch_anonymous
+      {
+         /* memory corruption: continue. */
+      }
+
+      ps->pwrite = NULL;
+      ps->piwrite = NULL;
+   }
+
+   /* And make sure that all the memory has been freed - this will output
+    * spurious errors in the case of memory corruption above, but this is safe.
+    */
+#  ifdef PNG_USER_MEM_SUPPORTED
+      store_pool_delete(ps, &ps->write_memory_pool);
+#  endif
+
+   store_freenew(ps);
+}
+
+/* The following is the main write function, it returns a png_struct and,
+ * optionally, a png_info suitable for writiing a new PNG file.  Use
+ * store_storefile above to record this file after it has been written.  The
+ * returned libpng structures as destroyed by store_write_reset above.
+ */
+static png_structp
+set_store_for_write(png_store *ps, png_infopp ppi, const char *name)
+{
+   anon_context(ps);
+
+   Try
+   {
+      if (ps->pwrite != NULL)
+         png_error(ps->pwrite, "write store already in use");
+
+      store_write_reset(ps);
+      safecat(ps->wname, sizeof ps->wname, 0, name);
+
+      /* Don't do the slow memory checks if doing a speed test, also if user
+       * memory is not supported we can't do it anyway.
+       */
+#     ifdef PNG_USER_MEM_SUPPORTED
+         if (!ps->speed)
+            ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
+               ps, store_error, store_warning, &ps->write_memory_pool,
+               store_malloc, store_free);
+
+         else
+#     endif
+         ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+            ps, store_error, store_warning);
+
+      png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
+
+#     ifdef PNG_SET_OPTION_SUPPORTED
+         {
+            int opt;
+            for (opt=0; opt<ps->noptions; ++opt)
+               if (png_set_option(ps->pwrite, ps->options[opt].option,
+                  ps->options[opt].setting) == PNG_OPTION_INVALID)
+                  png_error(ps->pwrite, "png option invalid");
+         }
+#     endif
+
+      if (ppi != NULL)
+         *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
+   }
+
+   Catch_anonymous
+      return NULL;
+
+   return ps->pwrite;
+}
+
+/* Cleanup when finished reading (either due to error or in the success case).
+ * This routine exists even when there is no read support to make the code
+ * tidier (avoid a mass of ifdefs) and so easier to maintain.
+ */
+static void
+store_read_reset(png_store *ps)
+{
+#  ifdef PNG_READ_SUPPORTED
+      if (ps->pread != NULL)
+      {
+         anon_context(ps);
+
+         Try
+            png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
+
+         Catch_anonymous
+         {
+            /* error already output: continue */
+         }
+
+         ps->pread = NULL;
+         ps->piread = NULL;
+      }
+#  endif
+
+#  ifdef PNG_USER_MEM_SUPPORTED
+      /* Always do this to be safe. */
+      store_pool_delete(ps, &ps->read_memory_pool);
+#  endif
+
+   ps->current = NULL;
+   ps->next = NULL;
+   ps->readpos = 0;
+   ps->validated = 0;
+
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+}
+
+#ifdef PNG_READ_SUPPORTED
+static void
+store_read_set(png_store *ps, png_uint_32 id)
+{
+   png_store_file *pf = ps->saved;
+
+   while (pf != NULL)
+   {
+      if (pf->id == id)
+      {
+         ps->current = pf;
+         ps->next = NULL;
+         ps->IDAT_size = pf->IDAT_size;
+         ps->IDAT_bits = pf->IDAT_bits; /* just a cache */
+         ps->IDAT_len = 0;
+         ps->IDAT_pos = 0;
+         ps->IDAT_crc = 0UL;
+         store_read_buffer_next(ps);
+         return;
+      }
+
+      pf = pf->next;
+   }
+
+   {
+      size_t pos;
+      char msg[FILE_NAME_SIZE+64];
+
+      pos = standard_name_from_id(msg, sizeof msg, 0, id);
+      pos = safecat(msg, sizeof msg, pos, ": file not found");
+      png_error(ps->pread, msg);
+   }
+}
+
+/* The main interface for reading a saved file - pass the id number of the file
+ * to retrieve.  Ids must be unique or the earlier file will be hidden.  The API
+ * returns a png_struct and, optionally, a png_info.  Both of these will be
+ * destroyed by store_read_reset above.
+ */
+static png_structp
+set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
+   const char *name)
+{
+   /* Set the name for png_error */
+   safecat(ps->test, sizeof ps->test, 0, name);
+
+   if (ps->pread != NULL)
+      png_error(ps->pread, "read store already in use");
+
+   store_read_reset(ps);
+
+   /* Both the create APIs can return NULL if used in their default mode
+    * (because there is no other way of handling an error because the jmp_buf
+    * by default is stored in png_struct and that has not been allocated!)
+    * However, given that store_error works correctly in these circumstances
+    * we don't ever expect NULL in this program.
+    */
+#  ifdef PNG_USER_MEM_SUPPORTED
+      if (!ps->speed)
+         ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
+             store_error, store_warning, &ps->read_memory_pool, store_malloc,
+             store_free);
+
+      else
+#  endif
+   ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps, store_error,
+      store_warning);
+
+   if (ps->pread == NULL)
+   {
+      struct exception_context *the_exception_context = &ps->exception_context;
+
+      store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
+         1 /*error*/);
+
+      Throw ps;
+   }
+
+#  ifdef PNG_SET_OPTION_SUPPORTED
+      {
+         int opt;
+         for (opt=0; opt<ps->noptions; ++opt)
+            if (png_set_option(ps->pread, ps->options[opt].option,
+               ps->options[opt].setting) == PNG_OPTION_INVALID)
+                  png_error(ps->pread, "png option invalid");
+      }
+#  endif
+
+   store_read_set(ps, id);
+
+   if (ppi != NULL)
+      *ppi = ps->piread = png_create_info_struct(ps->pread);
+
+   return ps->pread;
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* The overall cleanup of a store simply calls the above then removes all the
+ * saved files.  This does not delete the store itself.
+ */
+static void
+store_delete(png_store *ps)
+{
+   store_write_reset(ps);
+   store_read_reset(ps);
+   store_freefile(&ps->saved);
+   store_image_free(ps, NULL);
+}
+
+/*********************** PNG FILE MODIFICATION ON READ ************************/
+/* Files may be modified on read.  The following structure contains a complete
+ * png_store together with extra members to handle modification and a special
+ * read callback for libpng.  To use this the 'modifications' field must be set
+ * to a list of png_modification structures that actually perform the
+ * modification, otherwise a png_modifier is functionally equivalent to a
+ * png_store.  There is a special read function, set_modifier_for_read, which
+ * replaces set_store_for_read.
+ */
+typedef enum modifier_state
+{
+   modifier_start,                        /* Initial value */
+   modifier_signature,                    /* Have a signature */
+   modifier_IHDR                          /* Have an IHDR */
+} modifier_state;
+
+typedef struct CIE_color
+{
+   /* A single CIE tristimulus value, representing the unique response of a
+    * standard observer to a variety of light spectra.  The observer recognizes
+    * all spectra that produce this response as the same color, therefore this
+    * is effectively a description of a color.
+    */
+   double X, Y, Z;
+} CIE_color;
+
+typedef struct color_encoding
+{
+   /* A description of an (R,G,B) encoding of color (as defined above); this
+    * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
+    * (0,0,1) plus an encoding value that is used to encode the linear
+    * components R, G and B to give the actual values R^gamma, G^gamma and
+    * B^gamma that are stored.
+    */
+   double    gamma;            /* Encoding (file) gamma of space */
+   CIE_color red, green, blue; /* End points */
+} color_encoding;
+
+#ifdef PNG_READ_SUPPORTED
+#if defined PNG_READ_TRANSFORMS_SUPPORTED && defined PNG_READ_cHRM_SUPPORTED
+static double
+chromaticity_x(CIE_color c)
+{
+   return c.X / (c.X + c.Y + c.Z);
+}
+
+static double
+chromaticity_y(CIE_color c)
+{
+   return c.Y / (c.X + c.Y + c.Z);
+}
+
+static CIE_color
+white_point(const color_encoding *encoding)
+{
+   CIE_color white;
+
+   white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
+   white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
+   white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
+
+   return white;
+}
+#endif /* READ_TRANSFORMS && READ_cHRM */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+static void
+normalize_color_encoding(color_encoding *encoding)
+{
+   const double whiteY = encoding->red.Y + encoding->green.Y +
+      encoding->blue.Y;
+
+   if (whiteY != 1)
+   {
+      encoding->red.X /= whiteY;
+      encoding->red.Y /= whiteY;
+      encoding->red.Z /= whiteY;
+      encoding->green.X /= whiteY;
+      encoding->green.Y /= whiteY;
+      encoding->green.Z /= whiteY;
+      encoding->blue.X /= whiteY;
+      encoding->blue.Y /= whiteY;
+      encoding->blue.Z /= whiteY;
+   }
+}
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static size_t
+safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
+   const color_encoding *e, double encoding_gamma)
+{
+   if (e != 0)
+   {
+      if (encoding_gamma != 0)
+         pos = safecat(buffer, bufsize, pos, "(");
+      pos = safecat(buffer, bufsize, pos, "R(");
+      pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
+      pos = safecat(buffer, bufsize, pos, "),G(");
+      pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
+      pos = safecat(buffer, bufsize, pos, "),B(");
+      pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
+      pos = safecat(buffer, bufsize, pos, ")");
+      if (encoding_gamma != 0)
+         pos = safecat(buffer, bufsize, pos, ")");
+   }
+
+   if (encoding_gamma != 0)
+   {
+      pos = safecat(buffer, bufsize, pos, "^");
+      pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
+   }
+
+   return pos;
+}
+#endif /* READ_TRANSFORMS */
+#endif /* PNG_READ_SUPPORTED */
+
+typedef struct png_modifier
+{
+   png_store               this;             /* I am a png_store */
+   struct png_modification *modifications;   /* Changes to make */
+
+   modifier_state           state;           /* My state */
+
+   /* Information from IHDR: */
+   png_byte                 bit_depth;       /* From IHDR */
+   png_byte                 colour_type;     /* From IHDR */
+
+   /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
+    * other chunks to be inserted.
+    */
+   png_uint_32              pending_len;
+   png_uint_32              pending_chunk;
+
+   /* Test values */
+   double                   *gammas;
+   unsigned int              ngammas;
+   unsigned int              ngamma_tests;     /* Number of gamma tests to run*/
+   double                    current_gamma;    /* 0 if not set */
+   const color_encoding *encodings;
+   unsigned int              nencodings;
+   const color_encoding *current_encoding; /* If an encoding has been set */
+   unsigned int              encoding_counter; /* For iteration */
+   int                       encoding_ignored; /* Something overwrote it */
+
+   /* Control variables used to iterate through possible encodings, the
+    * following must be set to 0 and tested by the function that uses the
+    * png_modifier because the modifier only sets it to 1 (true.)
+    */
+   unsigned int              repeat :1;   /* Repeat this transform test. */
+   unsigned int              test_uses_encoding :1;
+
+   /* Lowest sbit to test (pre-1.7 libpng fails for sbit < 8) */
+   png_byte                 sbitlow;
+
+   /* Error control - these are the limits on errors accepted by the gamma tests
+    * below.
+    */
+   double                   maxout8;  /* Maximum output value error */
+   double                   maxabs8;  /* Absolute sample error 0..1 */
+   double                   maxcalc8; /* Absolute sample error 0..1 */
+   double                   maxpc8;   /* Percentage sample error 0..100% */
+   double                   maxout16; /* Maximum output value error */
+   double                   maxabs16; /* Absolute sample error 0..1 */
+   double                   maxcalc16;/* Absolute sample error 0..1 */
+   double                   maxcalcG; /* Absolute sample error 0..1 */
+   double                   maxpc16;  /* Percentage sample error 0..100% */
+
+   /* This is set by transforms that need to allow a higher limit, it is an
+    * internal check on pngvalid to ensure that the calculated error limits are
+    * not ridiculous; without this it is too easy to make a mistake in pngvalid
+    * that allows any value through.
+    *
+    * NOTE: this is not checked in release builds.
+    */
+   double                   limit;    /* limit on error values, normally 4E-3 */
+
+   /* Log limits - values above this are logged, but not necessarily
+    * warned.
+    */
+   double                   log8;     /* Absolute error in 8 bits to log */
+   double                   log16;    /* Absolute error in 16 bits to log */
+
+   /* Logged 8 and 16 bit errors ('output' values): */
+   double                   error_gray_2;
+   double                   error_gray_4;
+   double                   error_gray_8;
+   double                   error_gray_16;
+   double                   error_color_8;
+   double                   error_color_16;
+   double                   error_indexed;
+
+   /* Flags: */
+   /* Whether to call png_read_update_info, not png_read_start_image, and how
+    * many times to call it.
+    */
+   int                      use_update_info;
+
+   /* Whether or not to interlace. */
+   int                      interlace_type :9; /* int, but must store '1' */
+
+   /* Run the standard tests? */
+   unsigned int             test_standard :1;
+
+   /* Run the odd-sized image and interlace read/write tests? */
+   unsigned int             test_size :1;
+
+   /* Run tests on reading with a combination of transforms, */
+   unsigned int             test_transform :1;
+   unsigned int             test_tRNS :1; /* Includes tRNS images */
+
+   /* When to use the use_input_precision option, this controls the gamma
+    * validation code checks.  If set any value that is within the transformed
+    * range input-.5 to input+.5 will be accepted, otherwise the value must be
+    * within the normal limits.  It should not be necessary to set this; the
+    * result should always be exact within the permitted error limits.
+    */
+   unsigned int             use_input_precision :1;
+   unsigned int             use_input_precision_sbit :1;
+   unsigned int             use_input_precision_16to8 :1;
+
+   /* If set assume that the calculation bit depth is set by the input
+    * precision, not the output precision.
+    */
+   unsigned int             calculations_use_input_precision :1;
+
+   /* If set assume that the calculations are done in 16 bits even if the sample
+    * depth is 8 bits.
+    */
+   unsigned int             assume_16_bit_calculations :1;
+
+   /* Which gamma tests to run: */
+   unsigned int             test_gamma_threshold :1;
+   unsigned int             test_gamma_transform :1; /* main tests */
+   unsigned int             test_gamma_sbit :1;
+   unsigned int             test_gamma_scale16 :1;
+   unsigned int             test_gamma_background :1;
+   unsigned int             test_gamma_alpha_mode :1;
+   unsigned int             test_gamma_expand16 :1;
+   unsigned int             test_exhaustive :1;
+
+   /* Whether or not to run the low-bit-depth grayscale tests.  This fails on
+    * gamma images in some cases because of gross inaccuracies in the grayscale
+    * gamma handling for low bit depth.
+    */
+   unsigned int             test_lbg :1;
+   unsigned int             test_lbg_gamma_threshold :1;
+   unsigned int             test_lbg_gamma_transform :1;
+   unsigned int             test_lbg_gamma_sbit :1;
+   unsigned int             test_lbg_gamma_composition :1;
+
+   unsigned int             log :1;   /* Log max error */
+
+   /* Buffer information, the buffer size limits the size of the chunks that can
+    * be modified - they must fit (including header and CRC) into the buffer!
+    */
+   size_t                   flush;           /* Count of bytes to flush */
+   size_t                   buffer_count;    /* Bytes in buffer */
+   size_t                   buffer_position; /* Position in buffer */
+   png_byte                 buffer[1024];
+} png_modifier;
+
+/* This returns true if the test should be stopped now because it has already
+ * failed and it is running silently.
+  */
+static int fail(png_modifier *pm)
+{
+   return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
+       (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
+}
+
+static void
+modifier_init(png_modifier *pm)
+{
+   memset(pm, 0, sizeof *pm);
+   store_init(&pm->this);
+   pm->modifications = NULL;
+   pm->state = modifier_start;
+   pm->sbitlow = 1U;
+   pm->ngammas = 0;
+   pm->ngamma_tests = 0;
+   pm->gammas = 0;
+   pm->current_gamma = 0;
+   pm->encodings = 0;
+   pm->nencodings = 0;
+   pm->current_encoding = 0;
+   pm->encoding_counter = 0;
+   pm->encoding_ignored = 0;
+   pm->repeat = 0;
+   pm->test_uses_encoding = 0;
+   pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
+   pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
+   pm->maxcalcG = 0;
+   pm->limit = 4E-3;
+   pm->log8 = pm->log16 = 0; /* Means 'off' */
+   pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
+   pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
+   pm->error_indexed = 0;
+   pm->use_update_info = 0;
+   pm->interlace_type = PNG_INTERLACE_NONE;
+   pm->test_standard = 0;
+   pm->test_size = 0;
+   pm->test_transform = 0;
+#  ifdef PNG_WRITE_tRNS_SUPPORTED
+      pm->test_tRNS = 1;
+#  else
+      pm->test_tRNS = 0;
+#  endif
+   pm->use_input_precision = 0;
+   pm->use_input_precision_sbit = 0;
+   pm->use_input_precision_16to8 = 0;
+   pm->calculations_use_input_precision = 0;
+   pm->assume_16_bit_calculations = 0;
+   pm->test_gamma_threshold = 0;
+   pm->test_gamma_transform = 0;
+   pm->test_gamma_sbit = 0;
+   pm->test_gamma_scale16 = 0;
+   pm->test_gamma_background = 0;
+   pm->test_gamma_alpha_mode = 0;
+   pm->test_gamma_expand16 = 0;
+   pm->test_lbg = 1;
+   pm->test_lbg_gamma_threshold = 1;
+   pm->test_lbg_gamma_transform = 1;
+   pm->test_lbg_gamma_sbit = 1;
+   pm->test_lbg_gamma_composition = 1;
+   pm->test_exhaustive = 0;
+   pm->log = 0;
+
+   /* Rely on the memset for all the other fields - there are no pointers */
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+
+/* This controls use of checks that explicitly know how libpng digitizes the
+ * samples in calculations; setting this circumvents simple error limit checking
+ * in the rgb_to_gray check, replacing it with an exact copy of the libpng 1.5
+ * algorithm.
+ */
+#define DIGITIZE PNG_LIBPNG_VER < 10700
+
+/* If pm->calculations_use_input_precision is set then operations will happen
+ * with the precision of the input, not the precision of the output depth.
+ *
+ * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
+ * bit precision.  This only affects those of the following limits that pertain
+ * to a calculation - not a digitization operation - unless the following API is
+ * called directly.
+ */
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+#if DIGITIZE
+static double digitize(double value, int depth, int do_round)
+{
+   /* 'value' is in the range 0 to 1, the result is the same value rounded to a
+    * multiple of the digitization factor - 8 or 16 bits depending on both the
+    * sample depth and the 'assume' setting.  Digitization is normally by
+    * rounding and 'do_round' should be 1, if it is 0 the digitized value will
+    * be truncated.
+    */
+   unsigned int digitization_factor = (1U << depth) - 1;
+
+   /* Limiting the range is done as a convenience to the caller - it's easier to
+    * do it once here than every time at the call site.
+    */
+   if (value <= 0)
+      value = 0;
+
+   else if (value >= 1)
+      value = 1;
+
+   value *= digitization_factor;
+   if (do_round) value += .5;
+   return floor(value)/digitization_factor;
+}
+#endif
+#endif /* RGB_TO_GRAY */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+static double abserr(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* Absolute error permitted in linear values - affected by the bit depth of
+    * the calculations.
+    */
+   if (pm->assume_16_bit_calculations ||
+      (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+      return pm->maxabs16;
+   else
+      return pm->maxabs8;
+}
+
+static double calcerr(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* Error in the linear composition arithmetic - only relevant when
+    * composition actually happens (0 < alpha < 1).
+    */
+   if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+      return pm->maxcalc16;
+   else if (pm->assume_16_bit_calculations)
+      return pm->maxcalcG;
+   else
+      return pm->maxcalc8;
+}
+
+static double pcerr(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* Percentage error permitted in the linear values.  Note that the specified
+    * value is a percentage but this routine returns a simple number.
+    */
+   if (pm->assume_16_bit_calculations ||
+      (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+      return pm->maxpc16 * .01;
+   else
+      return pm->maxpc8 * .01;
+}
+
+/* Output error - the error in the encoded value.  This is determined by the
+ * digitization of the output so can be +/-0.5 in the actual output value.  In
+ * the expand_16 case with the current code in libpng the expand happens after
+ * all the calculations are done in 8 bit arithmetic, so even though the output
+ * depth is 16 the output error is determined by the 8 bit calculation.
+ *
+ * This limit is not determined by the bit depth of internal calculations.
+ *
+ * The specified parameter does *not* include the base .5 digitization error but
+ * it is added here.
+ */
+static double outerr(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* There is a serious error in the 2 and 4 bit grayscale transform because
+    * the gamma table value (8 bits) is simply shifted, not rounded, so the
+    * error in 4 bit grayscale gamma is up to the value below.  This is a hack
+    * to allow pngvalid to succeed:
+    *
+    * TODO: fix this in libpng
+    */
+   if (out_depth == 2)
+      return .73182-.5;
+
+   if (out_depth == 4)
+      return .90644-.5;
+
+   if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+      return pm->maxout16;
+
+   /* This is the case where the value was calculated at 8-bit precision then
+    * scaled to 16 bits.
+    */
+   else if (out_depth == 16)
+      return pm->maxout8 * 257;
+
+   else
+      return pm->maxout8;
+}
+
+/* This does the same thing as the above however it returns the value to log,
+ * rather than raising a warning.  This is useful for debugging to track down
+ * exactly what set of parameters cause high error values.
+ */
+static double outlog(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
+    * and so must be adjusted for low bit depth grayscale:
+    */
+   if (out_depth <= 8)
+   {
+      if (pm->log8 == 0) /* switched off */
+         return 256;
+
+      if (out_depth < 8)
+         return pm->log8 / 255 * ((1<<out_depth)-1);
+
+      return pm->log8;
+   }
+
+   if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+   {
+      if (pm->log16 == 0)
+         return 65536;
+
+      return pm->log16;
+   }
+
+   /* This is the case where the value was calculated at 8-bit precision then
+    * scaled to 16 bits.
+    */
+   if (pm->log8 == 0)
+      return 65536;
+
+   return pm->log8 * 257;
+}
+
+/* This complements the above by providing the appropriate quantization for the
+ * final value.  Normally this would just be quantization to an integral value,
+ * but in the 8 bit calculation case it's actually quantization to a multiple of
+ * 257!
+ */
+static int output_quantization_factor(const png_modifier *pm, int in_depth,
+   int out_depth)
+{
+   if (out_depth == 16 && in_depth != 16 &&
+      pm->calculations_use_input_precision)
+      return 257;
+   else
+      return 1;
+}
+#endif /* PNG_READ_GAMMA_SUPPORTED */
+
+/* One modification structure must be provided for each chunk to be modified (in
+ * fact more than one can be provided if multiple separate changes are desired
+ * for a single chunk.)  Modifications include adding a new chunk when a
+ * suitable chunk does not exist.
+ *
+ * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
+ * or 'added' as appropriate if the modify_fn returns 1 (true).  If the
+ * modify_fn is NULL the chunk is simply removed.
+ */
+typedef struct png_modification
+{
+   struct png_modification *next;
+   png_uint_32              chunk;
+
+   /* If the following is NULL all matching chunks will be removed: */
+   int                    (*modify_fn)(struct png_modifier *pm,
+                               struct png_modification *me, int add);
+
+   /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
+    * found and modified (and there is a modify_fn) the modify_fn will be called
+    * to add the chunk before the relevant chunk.
+    */
+   png_uint_32              add;
+   unsigned int             modified :1;     /* Chunk was modified */
+   unsigned int             added    :1;     /* Chunk was added */
+   unsigned int             removed  :1;     /* Chunk was removed */
+} png_modification;
+
+static void
+modification_reset(png_modification *pmm)
+{
+   if (pmm != NULL)
+   {
+      pmm->modified = 0;
+      pmm->added = 0;
+      pmm->removed = 0;
+      modification_reset(pmm->next);
+   }
+}
+
+static void
+modification_init(png_modification *pmm)
+{
+   memset(pmm, 0, sizeof *pmm);
+   pmm->next = NULL;
+   pmm->chunk = 0;
+   pmm->modify_fn = NULL;
+   pmm->add = 0;
+   modification_reset(pmm);
+}
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+static void
+modifier_current_encoding(const png_modifier *pm, color_encoding *ce)
+{
+   if (pm->current_encoding != 0)
+      *ce = *pm->current_encoding;
+
+   else
+      memset(ce, 0, sizeof *ce);
+
+   ce->gamma = pm->current_gamma;
+}
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static size_t
+safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
+   const png_modifier *pm)
+{
+   pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
+      pm->current_gamma);
+
+   if (pm->encoding_ignored)
+      pos = safecat(buffer, bufsize, pos, "[overridden]");
+
+   return pos;
+}
+#endif
+
+/* Iterate through the usefully testable color encodings.  An encoding is one
+ * of:
+ *
+ * 1) Nothing (no color space, no gamma).
+ * 2) Just a gamma value from the gamma array (including 1.0)
+ * 3) A color space from the encodings array with the corresponding gamma.
+ * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
+ *
+ * The iterator selects these in turn, the randomizer selects one at random,
+ * which is used depends on the setting of the 'test_exhaustive' flag.  Notice
+ * that this function changes the colour space encoding so it must only be
+ * called on completion of the previous test.  This is what 'modifier_reset'
+ * does, below.
+ *
+ * After the function has been called the 'repeat' flag will still be set; the
+ * caller of modifier_reset must reset it at the start of each run of the test!
+ */
+static unsigned int
+modifier_total_encodings(const png_modifier *pm)
+{
+   return 1 +                 /* (1) nothing */
+      pm->ngammas +           /* (2) gamma values to test */
+      pm->nencodings +        /* (3) total number of encodings */
+      /* The following test only works after the first time through the
+       * png_modifier code because 'bit_depth' is set when the IHDR is read.
+       * modifier_reset, below, preserves the setting until after it has called
+       * the iterate function (also below.)
+       *
+       * For this reason do not rely on this function outside a call to
+       * modifier_reset.
+       */
+      ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
+         pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
+}
+
+static void
+modifier_encoding_iterate(png_modifier *pm)
+{
+   if (!pm->repeat && /* Else something needs the current encoding again. */
+      pm->test_uses_encoding) /* Some transform is encoding dependent */
+   {
+      if (pm->test_exhaustive)
+      {
+         if (++pm->encoding_counter >= modifier_total_encodings(pm))
+            pm->encoding_counter = 0; /* This will stop the repeat */
+      }
+
+      else
+      {
+         /* Not exhaustive - choose an encoding at random; generate a number in
+          * the range 1..(max-1), so the result is always non-zero:
+          */
+         if (pm->encoding_counter == 0)
+            pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
+         else
+            pm->encoding_counter = 0;
+      }
+
+      if (pm->encoding_counter > 0)
+         pm->repeat = 1;
+   }
+
+   else if (!pm->repeat)
+      pm->encoding_counter = 0;
+}
+
+static void
+modifier_reset(png_modifier *pm)
+{
+   store_read_reset(&pm->this);
+   pm->limit = 4E-3;
+   pm->pending_len = pm->pending_chunk = 0;
+   pm->flush = pm->buffer_count = pm->buffer_position = 0;
+   pm->modifications = NULL;
+   pm->state = modifier_start;
+   modifier_encoding_iterate(pm);
+   /* The following must be set in the next run.  In particular
+    * test_uses_encodings must be set in the _ini function of each transform
+    * that looks at the encodings.  (Not the 'add' function!)
+    */
+   pm->test_uses_encoding = 0;
+   pm->current_gamma = 0;
+   pm->current_encoding = 0;
+   pm->encoding_ignored = 0;
+   /* These only become value after IHDR is read: */
+   pm->bit_depth = pm->colour_type = 0;
+}
+
+/* The following must be called before anything else to get the encoding set up
+ * on the modifier.  In particular it must be called before the transform init
+ * functions are called.
+ */
+static void
+modifier_set_encoding(png_modifier *pm)
+{
+   /* Set the encoding to the one specified by the current encoding counter,
+    * first clear out all the settings - this corresponds to an encoding_counter
+    * of 0.
+    */
+   pm->current_gamma = 0;
+   pm->current_encoding = 0;
+   pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
+
+   /* Now, if required, set the gamma and encoding fields. */
+   if (pm->encoding_counter > 0)
+   {
+      /* The gammas[] array is an array of screen gammas, not encoding gammas,
+       * so we need the inverse:
+       */
+      if (pm->encoding_counter <= pm->ngammas)
+         pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
+
+      else
+      {
+         unsigned int i = pm->encoding_counter - pm->ngammas;
+
+         if (i >= pm->nencodings)
+         {
+            i %= pm->nencodings;
+            pm->current_gamma = 1; /* Linear, only in the 16 bit case */
+         }
+
+         else
+            pm->current_gamma = pm->encodings[i].gamma;
+
+         pm->current_encoding = pm->encodings + i;
+      }
+   }
+}
+
+/* Enquiry functions to find out what is set.  Notice that there is an implicit
+ * assumption below that the first encoding in the list is the one for sRGB.
+ */
+static int
+modifier_color_encoding_is_sRGB(const png_modifier *pm)
+{
+   return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
+      pm->current_encoding->gamma == pm->current_gamma;
+}
+
+static int
+modifier_color_encoding_is_set(const png_modifier *pm)
+{
+   return pm->current_gamma != 0;
+}
+
+/* The guts of modification are performed during a read. */
+static void
+modifier_crc(png_bytep buffer)
+{
+   /* Recalculate the chunk CRC - a complete chunk must be in
+    * the buffer, at the start.
+    */
+   uInt datalen = png_get_uint_32(buffer);
+   uLong crc = crc32(0, buffer+4, datalen+4);
+   /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
+    */
+   png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
+}
+
+static void
+modifier_setbuffer(png_modifier *pm)
+{
+   modifier_crc(pm->buffer);
+   pm->buffer_count = png_get_uint_32(pm->buffer)+12;
+   pm->buffer_position = 0;
+}
+
+/* Separate the callback into the actual implementation (which is passed the
+ * png_modifier explicitly) and the callback, which gets the modifier from the
+ * png_struct.
+ */
+static void
+modifier_read_imp(png_modifier *pm, png_bytep pb, size_t st)
+{
+   while (st > 0)
+   {
+      size_t cb;
+      png_uint_32 len, chunk;
+      png_modification *mod;
+
+      if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
+      {
+         static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
+         case modifier_start:
+            store_read_chunk(&pm->this, pm->buffer, 8, 8); /* signature. */
+            pm->buffer_count = 8;
+            pm->buffer_position = 0;
+
+            if (memcmp(pm->buffer, sign, 8) != 0)
+               png_error(pm->this.pread, "invalid PNG file signature");
+            pm->state = modifier_signature;
+            break;
+
+         case modifier_signature:
+            store_read_chunk(&pm->this, pm->buffer, 13+12, 13+12); /* IHDR */
+            pm->buffer_count = 13+12;
+            pm->buffer_position = 0;
+
+            if (png_get_uint_32(pm->buffer) != 13 ||
+                png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
+               png_error(pm->this.pread, "invalid IHDR");
+
+            /* Check the list of modifiers for modifications to the IHDR. */
+            mod = pm->modifications;
+            while (mod != NULL)
+            {
+               if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
+                   (*mod->modify_fn)(pm, mod, 0))
+                  {
+                  mod->modified = 1;
+                  modifier_setbuffer(pm);
+                  }
+
+               /* Ignore removal or add if IHDR! */
+               mod = mod->next;
+            }
+
+            /* Cache information from the IHDR (the modified one.) */
+            pm->bit_depth = pm->buffer[8+8];
+            pm->colour_type = pm->buffer[8+8+1];
+
+            pm->state = modifier_IHDR;
+            pm->flush = 0;
+            break;
+
+         case modifier_IHDR:
+         default:
+            /* Read a new chunk and process it until we see PLTE, IDAT or
+             * IEND.  'flush' indicates that there is still some data to
+             * output from the preceding chunk.
+             */
+            if ((cb = pm->flush) > 0)
+            {
+               if (cb > st) cb = st;
+               pm->flush -= cb;
+               store_read_chunk(&pm->this, pb, cb, cb);
+               pb += cb;
+               st -= cb;
+               if (st == 0) return;
+            }
+
+            /* No more bytes to flush, read a header, or handle a pending
+             * chunk.
+             */
+            if (pm->pending_chunk != 0)
+            {
+               png_save_uint_32(pm->buffer, pm->pending_len);
+               png_save_uint_32(pm->buffer+4, pm->pending_chunk);
+               pm->pending_len = 0;
+               pm->pending_chunk = 0;
+            }
+            else
+               store_read_chunk(&pm->this, pm->buffer, 8, 8);
+
+            pm->buffer_count = 8;
+            pm->buffer_position = 0;
+
+            /* Check for something to modify or a terminator chunk. */
+            len = png_get_uint_32(pm->buffer);
+            chunk = png_get_uint_32(pm->buffer+4);
+
+            /* Terminators first, they may have to be delayed for added
+             * chunks
+             */
+            if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
+                chunk == CHUNK_IEND)
+            {
+               mod = pm->modifications;
+
+               while (mod != NULL)
+               {
+                  if ((mod->add == chunk ||
+                      (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
+                      mod->modify_fn != NULL && !mod->modified && !mod->added)
+                  {
+                     /* Regardless of what the modify function does do not run
+                      * this again.
+                      */
+                     mod->added = 1;
+
+                     if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
+                     {
+                        /* Reset the CRC on a new chunk */
+                        if (pm->buffer_count > 0)
+                           modifier_setbuffer(pm);
+
+                        else
+                           {
+                           pm->buffer_position = 0;
+                           mod->removed = 1;
+                           }
+
+                        /* The buffer has been filled with something (we assume)
+                         * so output this.  Pend the current chunk.
+                         */
+                        pm->pending_len = len;
+                        pm->pending_chunk = chunk;
+                        break; /* out of while */
+                     }
+                  }
+
+                  mod = mod->next;
+               }
+
+               /* Don't do any further processing if the buffer was modified -
+                * otherwise the code will end up modifying a chunk that was
+                * just added.
+                */
+               if (mod != NULL)
+                  break; /* out of switch */
+            }
+
+            /* If we get to here then this chunk may need to be modified.  To
+             * do this it must be less than 1024 bytes in total size, otherwise
+             * it just gets flushed.
+             */
+            if (len+12 <= sizeof pm->buffer)
+            {
+               size_t s = len+12-pm->buffer_count;
+               store_read_chunk(&pm->this, pm->buffer+pm->buffer_count, s, s);
+               pm->buffer_count = len+12;
+
+               /* Check for a modification, else leave it be. */
+               mod = pm->modifications;
+               while (mod != NULL)
+               {
+                  if (mod->chunk == chunk)
+                  {
+                     if (mod->modify_fn == NULL)
+                     {
+                        /* Remove this chunk */
+                        pm->buffer_count = pm->buffer_position = 0;
+                        mod->removed = 1;
+                        break; /* Terminate the while loop */
+                     }
+
+                     else if ((*mod->modify_fn)(pm, mod, 0))
+                     {
+                        mod->modified = 1;
+                        /* The chunk may have been removed: */
+                        if (pm->buffer_count == 0)
+                        {
+                           pm->buffer_position = 0;
+                           break;
+                        }
+                        modifier_setbuffer(pm);
+                     }
+                  }
+
+                  mod = mod->next;
+               }
+            }
+
+            else
+               pm->flush = len+12 - pm->buffer_count; /* data + crc */
+
+            /* Take the data from the buffer (if there is any). */
+            break;
+      }
+
+      /* Here to read from the modifier buffer (not directly from
+       * the store, as in the flush case above.)
+       */
+      cb = pm->buffer_count - pm->buffer_position;
+
+      if (cb > st)
+         cb = st;
+
+      memcpy(pb, pm->buffer + pm->buffer_position, cb);
+      st -= cb;
+      pb += cb;
+      pm->buffer_position += cb;
+   }
+}
+
+/* The callback: */
+static void PNGCBAPI
+modifier_read(png_structp ppIn, png_bytep pb, size_t st)
+{
+   png_const_structp pp = ppIn;
+   png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
+
+   if (pm == NULL || pm->this.pread != pp)
+      png_error(pp, "bad modifier_read call");
+
+   modifier_read_imp(pm, pb, st);
+}
+
+/* Like store_progressive_read but the data is getting changed as we go so we
+ * need a local buffer.
+ */
+static void
+modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
+{
+   if (pm->this.pread != pp || pm->this.current == NULL ||
+       pm->this.next == NULL)
+      png_error(pp, "store state damaged (progressive)");
+
+   /* This is another Horowitz and Hill random noise generator.  In this case
+    * the aim is to stress the progressive reader with truly horrible variable
+    * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
+    * is generated.  We could probably just count from 1 to 32767 and get as
+    * good a result.
+    */
+   for (;;)
+   {
+      static png_uint_32 noise = 1;
+      size_t cb, cbAvail;
+      png_byte buffer[512];
+
+      /* Generate 15 more bits of stuff: */
+      noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
+      cb = noise & 0x1ff;
+
+      /* Check that this number of bytes are available (in the current buffer.)
+       * (This doesn't quite work - the modifier might delete a chunk; unlikely
+       * but possible, it doesn't happen at present because the modifier only
+       * adds chunks to standard images.)
+       */
+      cbAvail = store_read_buffer_avail(&pm->this);
+      if (pm->buffer_count > pm->buffer_position)
+         cbAvail += pm->buffer_count - pm->buffer_position;
+
+      if (cb > cbAvail)
+      {
+         /* Check for EOF: */
+         if (cbAvail == 0)
+            break;
+
+         cb = cbAvail;
+      }
+
+      modifier_read_imp(pm, buffer, cb);
+      png_process_data(pp, pi, buffer, cb);
+   }
+
+   /* Check the invariants at the end (if this fails it's a problem in this
+    * file!)
+    */
+   if (pm->buffer_count > pm->buffer_position ||
+       pm->this.next != &pm->this.current->data ||
+       pm->this.readpos < pm->this.current->datacount)
+      png_error(pp, "progressive read implementation error");
+}
+
+/* Set up a modifier. */
+static png_structp
+set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
+    const char *name)
+{
+   /* Do this first so that the modifier fields are cleared even if an error
+    * happens allocating the png_struct.  No allocation is done here so no
+    * cleanup is required.
+    */
+   pm->state = modifier_start;
+   pm->bit_depth = 0;
+   pm->colour_type = 255;
+
+   pm->pending_len = 0;
+   pm->pending_chunk = 0;
+   pm->flush = 0;
+   pm->buffer_count = 0;
+   pm->buffer_position = 0;
+
+   return set_store_for_read(&pm->this, ppi, id, name);
+}
+
+
+/******************************** MODIFICATIONS *******************************/
+/* Standard modifications to add chunks.  These do not require the _SUPPORTED
+ * macros because the chunks can be there regardless of whether this specific
+ * libpng supports them.
+ */
+typedef struct gama_modification
+{
+   png_modification this;
+   png_fixed_point  gamma;
+} gama_modification;
+
+static int
+gama_modify(png_modifier *pm, png_modification *me, int add)
+{
+   UNUSED(add)
+   /* This simply dumps the given gamma value into the buffer. */
+   png_save_uint_32(pm->buffer, 4);
+   png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
+   png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
+   return 1;
+}
+
+static void
+gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
+{
+   double g;
+
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_gAMA;
+   me->this.modify_fn = gama_modify;
+   me->this.add = CHUNK_PLTE;
+   g = fix(gammad);
+   me->gamma = (png_fixed_point)g;
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+
+typedef struct chrm_modification
+{
+   png_modification          this;
+   const color_encoding *encoding;
+   png_fixed_point           wx, wy, rx, ry, gx, gy, bx, by;
+} chrm_modification;
+
+static int
+chrm_modify(png_modifier *pm, png_modification *me, int add)
+{
+   UNUSED(add)
+   /* As with gAMA this just adds the required cHRM chunk to the buffer. */
+   png_save_uint_32(pm->buffer   , 32);
+   png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
+   png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
+   png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
+   png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
+   png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
+   png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
+   png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
+   png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
+   png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
+   return 1;
+}
+
+static void
+chrm_modification_init(chrm_modification *me, png_modifier *pm,
+   const color_encoding *encoding)
+{
+   CIE_color white = white_point(encoding);
+
+   /* Original end points: */
+   me->encoding = encoding;
+
+   /* Chromaticities (in fixed point): */
+   me->wx = fix(chromaticity_x(white));
+   me->wy = fix(chromaticity_y(white));
+
+   me->rx = fix(chromaticity_x(encoding->red));
+   me->ry = fix(chromaticity_y(encoding->red));
+   me->gx = fix(chromaticity_x(encoding->green));
+   me->gy = fix(chromaticity_y(encoding->green));
+   me->bx = fix(chromaticity_x(encoding->blue));
+   me->by = fix(chromaticity_y(encoding->blue));
+
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_cHRM;
+   me->this.modify_fn = chrm_modify;
+   me->this.add = CHUNK_PLTE;
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+
+typedef struct srgb_modification
+{
+   png_modification this;
+   png_byte         intent;
+} srgb_modification;
+
+static int
+srgb_modify(png_modifier *pm, png_modification *me, int add)
+{
+   UNUSED(add)
+   /* As above, ignore add and just make a new chunk */
+   png_save_uint_32(pm->buffer, 1);
+   png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
+   pm->buffer[8] = ((srgb_modification*)me)->intent;
+   return 1;
+}
+
+static void
+srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
+{
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_sBIT;
+
+   if (intent <= 3) /* if valid, else *delete* sRGB chunks */
+   {
+      me->this.modify_fn = srgb_modify;
+      me->this.add = CHUNK_PLTE;
+      me->intent = intent;
+   }
+
+   else
+   {
+      me->this.modify_fn = 0;
+      me->this.add = 0;
+      me->intent = 0;
+   }
+
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+typedef struct sbit_modification
+{
+   png_modification this;
+   png_byte         sbit;
+} sbit_modification;
+
+static int
+sbit_modify(png_modifier *pm, png_modification *me, int add)
+{
+   png_byte sbit = ((sbit_modification*)me)->sbit;
+   if (pm->bit_depth > sbit)
+   {
+      int cb = 0;
+      switch (pm->colour_type)
+      {
+         case 0:
+            cb = 1;
+            break;
+
+         case 2:
+         case 3:
+            cb = 3;
+            break;
+
+         case 4:
+            cb = 2;
+            break;
+
+         case 6:
+            cb = 4;
+            break;
+
+         default:
+            png_error(pm->this.pread,
+               "unexpected colour type in sBIT modification");
+      }
+
+      png_save_uint_32(pm->buffer, cb);
+      png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
+
+      while (cb > 0)
+         (pm->buffer+8)[--cb] = sbit;
+
+      return 1;
+   }
+   else if (!add)
+   {
+      /* Remove the sBIT chunk */
+      pm->buffer_count = pm->buffer_position = 0;
+      return 1;
+   }
+   else
+      return 0; /* do nothing */
+}
+
+static void
+sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
+{
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_sBIT;
+   me->this.modify_fn = sbit_modify;
+   me->this.add = CHUNK_PLTE;
+   me->sbit = sbit;
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+#endif /* PNG_READ_GAMMA_SUPPORTED */
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+/***************************** STANDARD PNG FILES *****************************/
+/* Standard files - write and save standard files. */
+/* There are two basic forms of standard images.  Those which attempt to have
+ * all the possible pixel values (not possible for 16bpp images, but a range of
+ * values are produced) and those which have a range of image sizes.  The former
+ * are used for testing transforms, in particular gamma correction and bit
+ * reduction and increase.  The latter are reserved for testing the behavior of
+ * libpng with respect to 'odd' image sizes - particularly small images where
+ * rows become 1 byte and interlace passes disappear.
+ *
+ * The first, most useful, set are the 'transform' images, the second set of
+ * small images are the 'size' images.
+ *
+ * The transform files are constructed with rows which fit into a 1024 byte row
+ * buffer.  This makes allocation easier below.  Further regardless of the file
+ * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
+ *
+ * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
+ * and with an ID derived from the colour type, bit depth and interlace type
+ * as above (FILEID).  The width (128) and height (variable) are not stored in
+ * the FILEID - instead the fields are set to 0, indicating a transform file.
+ *
+ * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
+ * a maximum width of 16 pixels (for the 64bpp case.)  They also have a maximum
+ * height of 16 rows.  The width and height are stored in the FILEID and, being
+ * non-zero, indicate a size file.
+ *
+ * Because the PNG filter code is typically the largest CPU consumer within
+ * libpng itself there is a tendency to attempt to optimize it.  This results in
+ * special case code which needs to be validated.  To cause this to happen the
+ * 'size' images are made to use each possible filter, in so far as this is
+ * possible for smaller images.
+ *
+ * For palette image (colour type 3) multiple transform images are stored with
+ * the same bit depth to allow testing of more colour combinations -
+ * particularly important for testing the gamma code because libpng uses a
+ * different code path for palette images.  For size images a single palette is
+ * used.
+ */
+
+/* Make a 'standard' palette.  Because there are only 256 entries in a palette
+ * (maximum) this actually makes a random palette in the hope that enough tests
+ * will catch enough errors.  (Note that the same palette isn't produced every
+ * time for the same test - it depends on what previous tests have been run -
+ * but a given set of arguments to pngvalid will always produce the same palette
+ * at the same test!  This is why pseudo-random number generators are useful for
+ * testing.)
+ *
+ * The store must be open for write when this is called, otherwise an internal
+ * error will occur.  This routine contains its own magic number seed, so the
+ * palettes generated don't change if there are intervening errors (changing the
+ * calls to the store_mark seed.)
+ */
+static store_palette_entry *
+make_standard_palette(png_store* ps, int npalette, int do_tRNS)
+{
+   static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
+
+   int i = 0;
+   png_byte values[256][4];
+
+   /* Always put in black and white plus the six primary and secondary colors.
+    */
+   for (; i<8; ++i)
+   {
+      values[i][1] = (png_byte)((i&1) ? 255U : 0U);
+      values[i][2] = (png_byte)((i&2) ? 255U : 0U);
+      values[i][3] = (png_byte)((i&4) ? 255U : 0U);
+   }
+
+   /* Then add 62 grays (one quarter of the remaining 256 slots). */
+   {
+      int j = 0;
+      png_byte random_bytes[4];
+      png_byte need[256];
+
+      need[0] = 0; /*got black*/
+      memset(need+1, 1, (sizeof need)-2); /*need these*/
+      need[255] = 0; /*but not white*/
+
+      while (i<70)
+      {
+         png_byte b;
+
+         if (j==0)
+         {
+            make_four_random_bytes(palette_seed, random_bytes);
+            j = 4;
+         }
+
+         b = random_bytes[--j];
+         if (need[b])
+         {
+            values[i][1] = b;
+            values[i][2] = b;
+            values[i++][3] = b;
+         }
+      }
+   }
+
+   /* Finally add 192 colors at random - don't worry about matches to things we
+    * already have, chance is less than 1/65536.  Don't worry about grays,
+    * chance is the same, so we get a duplicate or extra gray less than 1 time
+    * in 170.
+    */
+   for (; i<256; ++i)
+      make_four_random_bytes(palette_seed, values[i]);
+
+   /* Fill in the alpha values in the first byte.  Just use all possible values
+    * (0..255) in an apparently random order:
+    */
+   {
+      store_palette_entry *palette;
+      png_byte selector[4];
+
+      make_four_random_bytes(palette_seed, selector);
+
+      if (do_tRNS)
+         for (i=0; i<256; ++i)
+            values[i][0] = (png_byte)(i ^ selector[0]);
+
+      else
+         for (i=0; i<256; ++i)
+            values[i][0] = 255; /* no transparency/tRNS chunk */
+
+      /* 'values' contains 256 ARGB values, but we only need 'npalette'.
+       * 'npalette' will always be a power of 2: 2, 4, 16 or 256.  In the low
+       * bit depth cases select colors at random, else it is difficult to have
+       * a set of low bit depth palette test with any chance of a reasonable
+       * range of colors.  Do this by randomly permuting values into the low
+       * 'npalette' entries using an XOR mask generated here.  This also
+       * permutes the npalette == 256 case in a potentially useful way (there is
+       * no relationship between palette index and the color value therein!)
+       */
+      palette = store_write_palette(ps, npalette);
+
+      for (i=0; i<npalette; ++i)
+      {
+         palette[i].alpha = values[i ^ selector[1]][0];
+         palette[i].red   = values[i ^ selector[1]][1];
+         palette[i].green = values[i ^ selector[1]][2];
+         palette[i].blue  = values[i ^ selector[1]][3];
+      }
+
+      return palette;
+   }
+}
+
+/* Initialize a standard palette on a write stream.  The 'do_tRNS' argument
+ * indicates whether or not to also set the tRNS chunk.
+ */
+/* TODO: the png_structp here can probably be 'const' in the future */
+static void
+init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
+   int do_tRNS)
+{
+   store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
+
+   {
+      int i;
+      png_color palette[256];
+
+      /* Set all entries to detect overread errors. */
+      for (i=0; i<npalette; ++i)
+      {
+         palette[i].red = ppal[i].red;
+         palette[i].green = ppal[i].green;
+         palette[i].blue = ppal[i].blue;
+      }
+
+      /* Just in case fill in the rest with detectable values: */
+      for (; i<256; ++i)
+         palette[i].red = palette[i].green = palette[i].blue = 42;
+
+      png_set_PLTE(pp, pi, palette, npalette);
+   }
+
+   if (do_tRNS)
+   {
+      int i, j;
+      png_byte tRNS[256];
+
+      /* Set all the entries, but skip trailing opaque entries */
+      for (i=j=0; i<npalette; ++i)
+         if ((tRNS[i] = ppal[i].alpha) < 255)
+            j = i+1;
+
+      /* Fill in the remainder with a detectable value: */
+      for (; i<256; ++i)
+         tRNS[i] = 24;
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+      if (j > 0)
+         png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
+#endif
+   }
+}
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+static void
+set_random_tRNS(png_structp pp, png_infop pi, png_byte colour_type,
+   int bit_depth)
+{
+   /* To make this useful the tRNS color needs to match at least one pixel.
+    * Random values are fine for gray, including the 16-bit case where we know
+    * that the test image contains all the gray values.  For RGB we need more
+    * method as only 65536 different RGB values are generated.
+    */
+   png_color_16 tRNS;
+   png_uint_16 mask = (png_uint_16)((1U << bit_depth)-1);
+
+   R8(tRNS); /* makes unset fields random */
+
+   if (colour_type & 2/*RGB*/)
+   {
+      if (bit_depth == 8)
+      {
+         tRNS.red = random_u16();
+         tRNS.green = random_u16();
+         tRNS.blue = tRNS.red ^ tRNS.green;
+         tRNS.red &= mask;
+         tRNS.green &= mask;
+         tRNS.blue &= mask;
+      }
+
+      else /* bit_depth == 16 */
+      {
+         tRNS.red = random_u16();
+         tRNS.green = (png_uint_16)(tRNS.red * 257);
+         tRNS.blue = (png_uint_16)(tRNS.green * 17);
+      }
+   }
+
+   else
+   {
+      tRNS.gray = random_u16();
+      tRNS.gray &= mask;
+   }
+
+   png_set_tRNS(pp, pi, NULL, 0, &tRNS);
+}
+#endif
+
+/* The number of passes is related to the interlace type. There was no libpng
+ * API to determine this prior to 1.5, so we need an inquiry function:
+ */
+static int
+npasses_from_interlace_type(png_const_structp pp, int interlace_type)
+{
+   switch (interlace_type)
+   {
+   default:
+      png_error(pp, "invalid interlace type");
+
+   case PNG_INTERLACE_NONE:
+      return 1;
+
+   case PNG_INTERLACE_ADAM7:
+      return PNG_INTERLACE_ADAM7_PASSES;
+   }
+}
+
+static unsigned int
+bit_size(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+   switch (colour_type)
+   {
+      default: png_error(pp, "invalid color type");
+
+      case 0:  return bit_depth;
+
+      case 2:  return 3*bit_depth;
+
+      case 3:  return bit_depth;
+
+      case 4:  return 2*bit_depth;
+
+      case 6:  return 4*bit_depth;
+   }
+}
+
+#define TRANSFORM_WIDTH  128U
+#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
+#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
+#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
+#define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
+
+static size_t
+transform_rowsize(png_const_structp pp, png_byte colour_type,
+   png_byte bit_depth)
+{
+   return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
+}
+
+/* transform_width(pp, colour_type, bit_depth) current returns the same number
+ * every time, so just use a macro:
+ */
+#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
+
+static png_uint_32
+transform_height(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+   switch (bit_size(pp, colour_type, bit_depth))
+   {
+      case 1:
+      case 2:
+      case 4:
+         return 1;   /* Total of 128 pixels */
+
+      case 8:
+         return 2;   /* Total of 256 pixels/bytes */
+
+      case 16:
+         return 512; /* Total of 65536 pixels */
+
+      case 24:
+      case 32:
+         return 512; /* 65536 pixels */
+
+      case 48:
+      case 64:
+         return 2048;/* 4 x 65536 pixels. */
+#        define TRANSFORM_HEIGHTMAX 2048
+
+      default:
+         return 0;   /* Error, will be caught later */
+   }
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* The following can only be defined here, now we have the definitions
+ * of the transform image sizes.
+ */
+static png_uint_32
+standard_width(png_const_structp pp, png_uint_32 id)
+{
+   png_uint_32 width = WIDTH_FROM_ID(id);
+   UNUSED(pp)
+
+   if (width == 0)
+      width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+
+   return width;
+}
+
+static png_uint_32
+standard_height(png_const_structp pp, png_uint_32 id)
+{
+   png_uint_32 height = HEIGHT_FROM_ID(id);
+
+   if (height == 0)
+      height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+
+   return height;
+}
+
+static png_uint_32
+standard_rowsize(png_const_structp pp, png_uint_32 id)
+{
+   png_uint_32 width = standard_width(pp, id);
+
+   /* This won't overflow: */
+   width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+   return (width + 7) / 8;
+}
+#endif /* PNG_READ_SUPPORTED */
+
+static void
+transform_row(png_const_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
+   png_byte colour_type, png_byte bit_depth, png_uint_32 y)
+{
+   png_uint_32 v = y << 7;
+   png_uint_32 i = 0;
+
+   switch (bit_size(pp, colour_type, bit_depth))
+   {
+      case 1:
+         while (i<128/8) buffer[i] = (png_byte)(v & 0xff), v += 17, ++i;
+         return;
+
+      case 2:
+         while (i<128/4) buffer[i] = (png_byte)(v & 0xff), v += 33, ++i;
+         return;
+
+      case 4:
+         while (i<128/2) buffer[i] = (png_byte)(v & 0xff), v += 65, ++i;
+         return;
+
+      case 8:
+         /* 256 bytes total, 128 bytes in each row set as follows: */
+         while (i<128) buffer[i] = (png_byte)(v & 0xff), ++v, ++i;
+         return;
+
+      case 16:
+         /* Generate all 65536 pixel values in order, which includes the 8 bit
+          * GA case as well as the 16 bit G case.
+          */
+         while (i<128)
+         {
+            buffer[2*i] = (png_byte)((v>>8) & 0xff);
+            buffer[2*i+1] = (png_byte)(v & 0xff);
+            ++v;
+            ++i;
+         }
+
+         return;
+
+      case 24:
+         /* 65535 pixels, but rotate the values. */
+         while (i<128)
+         {
+            /* Three bytes per pixel, r, g, b, make b by r^g */
+            buffer[3*i+0] = (png_byte)((v >> 8) & 0xff);
+            buffer[3*i+1] = (png_byte)(v & 0xff);
+            buffer[3*i+2] = (png_byte)(((v >> 8) ^ v) & 0xff);
+            ++v;
+            ++i;
+         }
+
+         return;
+
+      case 32:
+         /* 65535 pixels, r, g, b, a; just replicate */
+         while (i<128)
+         {
+            buffer[4*i+0] = (png_byte)((v >> 8) & 0xff);
+            buffer[4*i+1] = (png_byte)(v & 0xff);
+            buffer[4*i+2] = (png_byte)((v >> 8) & 0xff);
+            buffer[4*i+3] = (png_byte)(v & 0xff);
+            ++v;
+            ++i;
+         }
+
+         return;
+
+      case 48:
+         /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
+          * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
+          */
+         while (i<128)
+         {
+            png_uint_32 t = v++;
+            buffer[6*i+0] = (png_byte)((t >> 8) & 0xff);
+            buffer[6*i+1] = (png_byte)(t & 0xff);
+            t *= 257;
+            buffer[6*i+2] = (png_byte)((t >> 8) & 0xff);
+            buffer[6*i+3] = (png_byte)(t & 0xff);
+            t *= 17;
+            buffer[6*i+4] = (png_byte)((t >> 8) & 0xff);
+            buffer[6*i+5] = (png_byte)(t & 0xff);
+            ++i;
+         }
+
+         return;
+
+      case 64:
+         /* As above in the 32 bit case. */
+         while (i<128)
+         {
+            png_uint_32 t = v++;
+            buffer[8*i+0] = (png_byte)((t >> 8) & 0xff);
+            buffer[8*i+1] = (png_byte)(t & 0xff);
+            buffer[8*i+4] = (png_byte)((t >> 8) & 0xff);
+            buffer[8*i+5] = (png_byte)(t & 0xff);
+            t *= 257;
+            buffer[8*i+2] = (png_byte)((t >> 8) & 0xff);
+            buffer[8*i+3] = (png_byte)(t & 0xff);
+            buffer[8*i+6] = (png_byte)((t >> 8) & 0xff);
+            buffer[8*i+7] = (png_byte)(t & 0xff);
+            ++i;
+         }
+         return;
+
+      default:
+         break;
+   }
+
+   png_error(pp, "internal error");
+}
+
+/* This is just to do the right cast - could be changed to a function to check
+ * 'bd' but there isn't much point.
+ */
+#define DEPTH(bd) ((png_byte)(1U << (bd)))
+
+/* This is just a helper for compiling on minimal systems with no write
+ * interlacing support.  If there is no write interlacing we can't generate test
+ * cases with interlace:
+ */
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+#  define INTERLACE_LAST PNG_INTERLACE_LAST
+#  define check_interlace_type(type) ((void)(type))
+#  define set_write_interlace_handling(pp,type) png_set_interlace_handling(pp)
+#  define do_own_interlace 0
+#elif PNG_LIBPNG_VER < 10700
+#  define set_write_interlace_handling(pp,type) (1)
+static void
+check_interlace_type(int const interlace_type)
+{
+   /* Prior to 1.7.0 libpng does not support the write of an interlaced image
+    * unless PNG_WRITE_INTERLACING_SUPPORTED, even with do_interlace so the
+    * code here does the pixel interlace itself, so:
+    */
+   if (interlace_type != PNG_INTERLACE_NONE)
+   {
+      /* This is an internal error - --interlace tests should be skipped, not
+       * attempted.
+       */
+      fprintf(stderr, "pngvalid: no interlace support\n");
+      exit(99);
+   }
+}
+#  define INTERLACE_LAST (PNG_INTERLACE_NONE+1)
+#  define do_own_interlace 0
+#else /* libpng 1.7+ */
+#  define set_write_interlace_handling(pp,type)\
+      npasses_from_interlace_type(pp,type)
+#  define check_interlace_type(type) ((void)(type))
+#  define INTERLACE_LAST PNG_INTERLACE_LAST
+#  define do_own_interlace 1
+#endif /* WRITE_INTERLACING tests */
+
+#if PNG_LIBPNG_VER >= 10700 || defined PNG_WRITE_INTERLACING_SUPPORTED
+#   define CAN_WRITE_INTERLACE 1
+#else
+#   define CAN_WRITE_INTERLACE 0
+#endif
+
+/* Do the same thing for read interlacing; this controls whether read tests do
+ * their own de-interlace or use libpng.
+ */
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+#  define do_read_interlace 0
+#else /* no libpng read interlace support */
+#  define do_read_interlace 1
+#endif
+/* The following two routines use the PNG interlace support macros from
+ * png.h to interlace or deinterlace rows.
+ */
+static void
+interlace_row(png_bytep buffer, png_const_bytep imageRow,
+   unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
+{
+   png_uint_32 xin, xout, xstep;
+
+   /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
+    * code is presented this way to make it easier to understand.  In practice
+    * consult the code in the libpng source to see other ways of doing this.
+    *
+    * It is OK for buffer and imageRow to be identical, because 'xin' moves
+    * faster than 'xout' and we copy up.
+    */
+   xin = PNG_PASS_START_COL(pass);
+   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
+
+   for (xout=0; xin<w; xin+=xstep)
+   {
+      pixel_copy(buffer, xout, imageRow, xin, pixel_size, littleendian);
+      ++xout;
+   }
+}
+
+#ifdef PNG_READ_SUPPORTED
+static void
+deinterlace_row(png_bytep buffer, png_const_bytep row,
+   unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
+{
+   /* The inverse of the above, 'row' is part of row 'y' of the output image,
+    * in 'buffer'.  The image is 'w' wide and this is pass 'pass', distribute
+    * the pixels of row into buffer and return the number written (to allow
+    * this to be checked).
+    */
+   png_uint_32 xin, xout, xstep;
+
+   xout = PNG_PASS_START_COL(pass);
+   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
+
+   for (xin=0; xout<w; xout+=xstep)
+   {
+      pixel_copy(buffer, xout, row, xin, pixel_size, littleendian);
+      ++xin;
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* Make a standardized image given an image colour type, bit depth and
+ * interlace type.  The standard images have a very restricted range of
+ * rows and heights and are used for testing transforms rather than image
+ * layout details.  See make_size_images below for a way to make images
+ * that test odd sizes along with the libpng interlace handling.
+ */
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+static void
+choose_random_filter(png_structp pp, int start)
+{
+   /* Choose filters randomly except that on the very first row ensure that
+    * there is at least one previous row filter.
+    */
+   int filters = PNG_ALL_FILTERS & random_mod(256U);
+
+   /* There may be no filters; skip the setting. */
+   if (filters != 0)
+   {
+      if (start && filters < PNG_FILTER_UP)
+         filters |= PNG_FILTER_UP;
+
+      png_set_filter(pp, 0/*method*/, filters);
+   }
+}
+#else /* !WRITE_FILTER */
+#  define choose_random_filter(pp, start) ((void)0)
+#endif /* !WRITE_FILTER */
+
+static void
+make_transform_image(png_store* const ps, png_byte const colour_type,
+    png_byte const bit_depth, unsigned int palette_number,
+    int interlace_type, png_const_charp name)
+{
+   context(ps, fault);
+
+   check_interlace_type(interlace_type);
+
+   Try
+   {
+      png_infop pi;
+      png_structp pp = set_store_for_write(ps, &pi, name);
+      png_uint_32 h, w;
+
+      /* In the event of a problem return control to the Catch statement below
+       * to do the clean up - it is not possible to 'return' directly from a Try
+       * block.
+       */
+      if (pp == NULL)
+         Throw ps;
+
+      w = transform_width(pp, colour_type, bit_depth);
+      h = transform_height(pp, colour_type, bit_depth);
+
+      png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
+         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+#ifdef PNG_TEXT_SUPPORTED
+#  if defined(PNG_READ_zTXt_SUPPORTED) && defined(PNG_WRITE_zTXt_SUPPORTED)
+#     define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_zTXt
+#  else
+#     define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_NONE
+#  endif
+      {
+         static char key[] = "image name"; /* must be writeable */
+         size_t pos;
+         png_text text;
+         char copy[FILE_NAME_SIZE];
+
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = TEXT_COMPRESSION;
+         text.key = key;
+         /* Yuck: the text must be writable! */
+         pos = safecat(copy, sizeof copy, 0, ps->wname);
+         text.text = copy;
+         text.text_length = pos;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+
+      if (colour_type == 3) /* palette */
+         init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
+
+#     ifdef PNG_WRITE_tRNS_SUPPORTED
+         else if (palette_number)
+            set_random_tRNS(pp, pi, colour_type, bit_depth);
+#     endif
+
+      png_write_info(pp, pi);
+
+      if (png_get_rowbytes(pp, pi) !=
+          transform_rowsize(pp, colour_type, bit_depth))
+         png_error(pp, "transform row size incorrect");
+
+      else
+      {
+         /* Somewhat confusingly this must be called *after* png_write_info
+          * because if it is called before, the information in *pp has not been
+          * updated to reflect the interlaced image.
+          */
+         int npasses = set_write_interlace_handling(pp, interlace_type);
+         int pass;
+
+         if (npasses != npasses_from_interlace_type(pp, interlace_type))
+            png_error(pp, "write: png_set_interlace_handling failed");
+
+         for (pass=0; pass<npasses; ++pass)
+         {
+            png_uint_32 y;
+
+            /* do_own_interlace is a pre-defined boolean (a #define) which is
+             * set if we have to work out the interlaced rows here.
+             */
+            for (y=0; y<h; ++y)
+            {
+               png_byte buffer[TRANSFORM_ROWMAX];
+
+               transform_row(pp, buffer, colour_type, bit_depth, y);
+
+#              if do_own_interlace
+                  /* If do_own_interlace *and* the image is interlaced we need a
+                   * reduced interlace row; this may be reduced to empty.
+                   */
+                  if (interlace_type == PNG_INTERLACE_ADAM7)
+                  {
+                     /* The row must not be written if it doesn't exist, notice
+                      * that there are two conditions here, either the row isn't
+                      * ever in the pass or the row would be but isn't wide
+                      * enough to contribute any pixels.  In fact the wPass test
+                      * can be used to skip the whole y loop in this case.
+                      */
+                     if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
+                         PNG_PASS_COLS(w, pass) > 0)
+                        interlace_row(buffer, buffer,
+                              bit_size(pp, colour_type, bit_depth), w, pass,
+                              0/*data always bigendian*/);
+                     else
+                        continue;
+                  }
+#              endif /* do_own_interlace */
+
+               choose_random_filter(pp, pass == 0 && y == 0);
+               png_write_row(pp, buffer);
+            }
+         }
+      }
+
+#ifdef PNG_TEXT_SUPPORTED
+      {
+         static char key[] = "end marker";
+         static char comment[] = "end";
+         png_text text;
+
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = TEXT_COMPRESSION;
+         text.key = key;
+         text.text = comment;
+         text.text_length = (sizeof comment)-1;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+
+      png_write_end(pp, pi);
+
+      /* And store this under the appropriate id, then clean up. */
+      store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
+         interlace_type, 0, 0, 0));
+
+      store_write_reset(ps);
+   }
+
+   Catch(fault)
+   {
+      /* Use the png_store returned by the exception. This may help the compiler
+       * because 'ps' is not used in this branch of the setjmp.  Note that fault
+       * and ps will always be the same value.
+       */
+      store_write_reset(fault);
+   }
+}
+
+static void
+make_transform_images(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   /* This is in case of errors. */
+   safecat(pm->this.test, sizeof pm->this.test, 0, "make standard images");
+
+   /* Use next_format to enumerate all the combinations we test, including
+    * generating multiple low bit depth palette images. Non-A images (palette
+    * and direct) are created with and without tRNS chunks.
+    */
+   while (next_format(&colour_type, &bit_depth, &palette_number, 1, 1))
+   {
+      int interlace_type;
+
+      for (interlace_type = PNG_INTERLACE_NONE;
+           interlace_type < INTERLACE_LAST; ++interlace_type)
+      {
+         char name[FILE_NAME_SIZE];
+
+         standard_name(name, sizeof name, 0, colour_type, bit_depth,
+            palette_number, interlace_type, 0, 0, do_own_interlace);
+         make_transform_image(&pm->this, colour_type, bit_depth, palette_number,
+            interlace_type, name);
+      }
+   }
+}
+
+/* Build a single row for the 'size' test images; this fills in only the
+ * first bit_width bits of the sample row.
+ */
+static void
+size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
+{
+   /* height is in the range 1 to 16, so: */
+   y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
+   /* the following ensures bits are set in small images: */
+   y ^= 0xA5;
+
+   while (bit_width >= 8)
+      *buffer++ = (png_byte)y++, bit_width -= 8;
+
+   /* There may be up to 7 remaining bits, these go in the most significant
+    * bits of the byte.
+    */
+   if (bit_width > 0)
+   {
+      png_uint_32 mask = (1U<<(8-bit_width))-1;
+      *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
+   }
+}
+
+static void
+make_size_image(png_store* const ps, png_byte const colour_type,
+    png_byte const bit_depth, int const interlace_type,
+    png_uint_32 const w, png_uint_32 const h,
+    int const do_interlace)
+{
+   context(ps, fault);
+
+   check_interlace_type(interlace_type);
+
+   Try
+   {
+      png_infop pi;
+      png_structp pp;
+      unsigned int pixel_size;
+
+      /* Make a name and get an appropriate id for the store: */
+      char name[FILE_NAME_SIZE];
+      png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
+         interlace_type, w, h, do_interlace);
+
+      standard_name_from_id(name, sizeof name, 0, id);
+      pp = set_store_for_write(ps, &pi, name);
+
+      /* In the event of a problem return control to the Catch statement below
+       * to do the clean up - it is not possible to 'return' directly from a Try
+       * block.
+       */
+      if (pp == NULL)
+         Throw ps;
+
+      png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
+         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+#ifdef PNG_TEXT_SUPPORTED
+      {
+         static char key[] = "image name"; /* must be writeable */
+         size_t pos;
+         png_text text;
+         char copy[FILE_NAME_SIZE];
+
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = TEXT_COMPRESSION;
+         text.key = key;
+         /* Yuck: the text must be writable! */
+         pos = safecat(copy, sizeof copy, 0, ps->wname);
+         text.text = copy;
+         text.text_length = pos;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+
+      if (colour_type == 3) /* palette */
+         init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
+
+      png_write_info(pp, pi);
+
+      /* Calculate the bit size, divide by 8 to get the byte size - this won't
+       * overflow because we know the w values are all small enough even for
+       * a system where 'unsigned int' is only 16 bits.
+       */
+      pixel_size = bit_size(pp, colour_type, bit_depth);
+      if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
+         png_error(pp, "size row size incorrect");
+
+      else
+      {
+         int npasses = npasses_from_interlace_type(pp, interlace_type);
+         png_uint_32 y;
+         int pass;
+         png_byte image[16][SIZE_ROWMAX];
+
+         /* To help consistent error detection make the parts of this buffer
+          * that aren't set below all '1':
+          */
+         memset(image, 0xff, sizeof image);
+
+         if (!do_interlace &&
+             npasses != set_write_interlace_handling(pp, interlace_type))
+            png_error(pp, "write: png_set_interlace_handling failed");
+
+         /* Prepare the whole image first to avoid making it 7 times: */
+         for (y=0; y<h; ++y)
+            size_row(image[y], w * pixel_size, y);
+
+         for (pass=0; pass<npasses; ++pass)
+         {
+            /* The following two are for checking the macros: */
+            png_uint_32 wPass = PNG_PASS_COLS(w, pass);
+
+            /* If do_interlace is set we don't call png_write_row for every
+             * row because some of them are empty.  In fact, for a 1x1 image,
+             * most of them are empty!
+             */
+            for (y=0; y<h; ++y)
+            {
+               png_const_bytep row = image[y];
+               png_byte tempRow[SIZE_ROWMAX];
+
+               /* If do_interlace *and* the image is interlaced we
+                * need a reduced interlace row; this may be reduced
+                * to empty.
+                */
+               if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
+               {
+                  /* The row must not be written if it doesn't exist, notice
+                   * that there are two conditions here, either the row isn't
+                   * ever in the pass or the row would be but isn't wide
+                   * enough to contribute any pixels.  In fact the wPass test
+                   * can be used to skip the whole y loop in this case.
+                   */
+                  if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
+                  {
+                     /* Set to all 1's for error detection (libpng tends to
+                      * set unset things to 0).
+                      */
+                     memset(tempRow, 0xff, sizeof tempRow);
+                     interlace_row(tempRow, row, pixel_size, w, pass,
+                           0/*data always bigendian*/);
+                     row = tempRow;
+                  }
+                  else
+                     continue;
+               }
+
+#           ifdef PNG_WRITE_FILTER_SUPPORTED
+               /* Only get to here if the row has some pixels in it, set the
+                * filters to 'all' for the very first row and thereafter to a
+                * single filter.  It isn't well documented, but png_set_filter
+                * does accept a filter number (per the spec) as well as a bit
+                * mask.
+                *
+                * The code now uses filters at random, except that on the first
+                * row of an image it ensures that a previous row filter is in
+                * the set so that libpng allocates the row buffer.
+                */
+               {
+                  int filters = 8 << random_mod(PNG_FILTER_VALUE_LAST);
+
+                  if (pass == 0 && y == 0 &&
+                      (filters < PNG_FILTER_UP || w == 1U))
+                     filters |= PNG_FILTER_UP;
+
+                  png_set_filter(pp, 0/*method*/, filters);
+               }
+#           endif
+
+               png_write_row(pp, row);
+            }
+         }
+      }
+
+#ifdef PNG_TEXT_SUPPORTED
+      {
+         static char key[] = "end marker";
+         static char comment[] = "end";
+         png_text text;
+
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = TEXT_COMPRESSION;
+         text.key = key;
+         text.text = comment;
+         text.text_length = (sizeof comment)-1;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+
+      png_write_end(pp, pi);
+
+      /* And store this under the appropriate id, then clean up. */
+      store_storefile(ps, id);
+
+      store_write_reset(ps);
+   }
+
+   Catch(fault)
+   {
+      /* Use the png_store returned by the exception. This may help the compiler
+       * because 'ps' is not used in this branch of the setjmp.  Note that fault
+       * and ps will always be the same value.
+       */
+      store_write_reset(fault);
+   }
+}
+
+static void
+make_size(png_store* const ps, png_byte const colour_type, int bdlo,
+    int const bdhi)
+{
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      png_uint_32 width;
+
+      for (width = 1; width <= 16; ++width)
+      {
+         png_uint_32 height;
+
+         for (height = 1; height <= 16; ++height)
+         {
+            /* The four combinations of DIY interlace and interlace or not -
+             * no interlace + DIY should be identical to no interlace with
+             * libpng doing it.
+             */
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
+               width, height, 0);
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
+               width, height, 1);
+#        ifdef PNG_WRITE_INTERLACING_SUPPORTED
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
+               width, height, 0);
+#        endif
+#        if CAN_WRITE_INTERLACE
+            /* 1.7.0 removes the hack that prevented app write of an interlaced
+             * image if WRITE_INTERLACE was not supported
+             */
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
+               width, height, 1);
+#        endif
+         }
+      }
+   }
+}
+
+static void
+make_size_images(png_store *ps)
+{
+   /* This is in case of errors. */
+   safecat(ps->test, sizeof ps->test, 0, "make size images");
+
+   /* Arguments are colour_type, low bit depth, high bit depth
+    */
+   make_size(ps, 0, 0, WRITE_BDHI);
+   make_size(ps, 2, 3, WRITE_BDHI);
+   make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
+   make_size(ps, 4, 3, WRITE_BDHI);
+   make_size(ps, 6, 3, WRITE_BDHI);
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* Return a row based on image id and 'y' for checking: */
+static void
+standard_row(png_const_structp pp, png_byte std[STANDARD_ROWMAX],
+   png_uint_32 id, png_uint_32 y)
+{
+   if (WIDTH_FROM_ID(id) == 0)
+      transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
+   else
+      size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
+         DEPTH_FROM_ID(id)), y);
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* Tests - individual test cases */
+/* Like 'make_standard' but errors are deliberately introduced into the calls
+ * to ensure that they get detected - it should not be possible to write an
+ * invalid image with libpng!
+ */
+/* TODO: the 'set' functions can probably all be made to take a
+ * png_const_structp rather than a modifiable one.
+ */
+#ifdef PNG_WARNINGS_SUPPORTED
+static void
+sBIT0_error_fn(png_structp pp, png_infop pi)
+{
+   /* 0 is invalid... */
+   png_color_8 bad;
+   bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
+   png_set_sBIT(pp, pi, &bad);
+}
+
+static void
+sBIT_error_fn(png_structp pp, png_infop pi)
+{
+   png_byte bit_depth;
+   png_color_8 bad;
+
+   if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
+      bit_depth = 8;
+
+   else
+      bit_depth = png_get_bit_depth(pp, pi);
+
+   /* Now we know the bit depth we can easily generate an invalid sBIT entry */
+   bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
+      (png_byte)(bit_depth+1);
+   png_set_sBIT(pp, pi, &bad);
+}
+
+static const struct
+{
+   void          (*fn)(png_structp, png_infop);
+   const char *msg;
+   unsigned int    warning :1; /* the error is a warning... */
+} error_test[] =
+    {
+       /* no warnings makes these errors undetectable prior to 1.7.0 */
+       { sBIT0_error_fn, "sBIT(0): failed to detect error",
+         PNG_LIBPNG_VER < 10700 },
+
+       { sBIT_error_fn, "sBIT(too big): failed to detect error",
+         PNG_LIBPNG_VER < 10700 },
+    };
+
+static void
+make_error(png_store* const ps, png_byte const colour_type,
+    png_byte bit_depth, int interlace_type, int test, png_const_charp name)
+{
+   context(ps, fault);
+
+   check_interlace_type(interlace_type);
+
+   Try
+   {
+      png_infop pi;
+      png_structp pp = set_store_for_write(ps, &pi, name);
+      png_uint_32 w, h;
+      gnu_volatile(pp)
+
+      if (pp == NULL)
+         Throw ps;
+
+      w = transform_width(pp, colour_type, bit_depth);
+      gnu_volatile(w)
+      h = transform_height(pp, colour_type, bit_depth);
+      gnu_volatile(h)
+      png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
+            PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+      if (colour_type == 3) /* palette */
+         init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
+
+      /* Time for a few errors; these are in various optional chunks, the
+       * standard tests test the standard chunks pretty well.
+       */
+#     define exception__prev exception_prev_1
+#     define exception__env exception_env_1
+      Try
+      {
+         gnu_volatile(exception__prev)
+
+         /* Expect this to throw: */
+         ps->expect_error = !error_test[test].warning;
+         ps->expect_warning = error_test[test].warning;
+         ps->saw_warning = 0;
+         error_test[test].fn(pp, pi);
+
+         /* Normally the error is only detected here: */
+         png_write_info(pp, pi);
+
+         /* And handle the case where it was only a warning: */
+         if (ps->expect_warning && ps->saw_warning)
+            Throw ps;
+
+         /* If we get here there is a problem, we have success - no error or
+          * no warning - when we shouldn't have success.  Log an error.
+          */
+         store_log(ps, pp, error_test[test].msg, 1 /*error*/);
+      }
+
+      Catch (fault)
+      { /* expected exit */
+      }
+#undef exception__prev
+#undef exception__env
+
+      /* And clear these flags */
+      ps->expect_warning = 0;
+
+      if (ps->expect_error)
+         ps->expect_error = 0;
+
+      else
+      {
+         /* Now write the whole image, just to make sure that the detected, or
+          * undetected, error has not created problems inside libpng.  This
+          * doesn't work if there was a png_error in png_write_info because that
+          * can abort before PLTE was written.
+          */
+         if (png_get_rowbytes(pp, pi) !=
+             transform_rowsize(pp, colour_type, bit_depth))
+            png_error(pp, "row size incorrect");
+
+         else
+         {
+            int npasses = set_write_interlace_handling(pp, interlace_type);
+            int pass;
+
+            if (npasses != npasses_from_interlace_type(pp, interlace_type))
+               png_error(pp, "write: png_set_interlace_handling failed");
+
+            for (pass=0; pass<npasses; ++pass)
+            {
+               png_uint_32 y;
+
+               for (y=0; y<h; ++y)
+               {
+                  png_byte buffer[TRANSFORM_ROWMAX];
+
+                  transform_row(pp, buffer, colour_type, bit_depth, y);
+
+#                 if do_own_interlace
+                     /* If do_own_interlace *and* the image is interlaced we
+                      * need a reduced interlace row; this may be reduced to
+                      * empty.
+                      */
+                     if (interlace_type == PNG_INTERLACE_ADAM7)
+                     {
+                        /* The row must not be written if it doesn't exist,
+                         * notice that there are two conditions here, either the
+                         * row isn't ever in the pass or the row would be but
+                         * isn't wide enough to contribute any pixels.  In fact
+                         * the wPass test can be used to skip the whole y loop
+                         * in this case.
+                         */
+                        if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
+                            PNG_PASS_COLS(w, pass) > 0)
+                           interlace_row(buffer, buffer,
+                                 bit_size(pp, colour_type, bit_depth), w, pass,
+                                 0/*data always bigendian*/);
+                        else
+                           continue;
+                     }
+#                 endif /* do_own_interlace */
+
+                  png_write_row(pp, buffer);
+               }
+            }
+         } /* image writing */
+
+         png_write_end(pp, pi);
+      }
+
+      /* The following deletes the file that was just written. */
+      store_write_reset(ps);
+   }
+
+   Catch(fault)
+   {
+      store_write_reset(fault);
+   }
+}
+
+static int
+make_errors(png_modifier* const pm, png_byte const colour_type,
+    int bdlo, int const bdhi)
+{
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      int interlace_type;
+
+      for (interlace_type = PNG_INTERLACE_NONE;
+           interlace_type < INTERLACE_LAST; ++interlace_type)
+      {
+         unsigned int test;
+         char name[FILE_NAME_SIZE];
+
+         standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
+            interlace_type, 0, 0, do_own_interlace);
+
+         for (test=0; test<ARRAY_SIZE(error_test); ++test)
+         {
+            make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
+               test, name);
+
+            if (fail(pm))
+               return 0;
+         }
+      }
+   }
+
+   return 1; /* keep going */
+}
+#endif /* PNG_WARNINGS_SUPPORTED */
+
+static void
+perform_error_test(png_modifier *pm)
+{
+#ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
+   /* Need to do this here because we just write in this test. */
+   safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
+
+   if (!make_errors(pm, 0, 0, WRITE_BDHI))
+      return;
+
+   if (!make_errors(pm, 2, 3, WRITE_BDHI))
+      return;
+
+   if (!make_errors(pm, 3, 0, 3))
+      return;
+
+   if (!make_errors(pm, 4, 3, WRITE_BDHI))
+      return;
+
+   if (!make_errors(pm, 6, 3, WRITE_BDHI))
+      return;
+#else
+   UNUSED(pm)
+#endif
+}
+
+/* This is just to validate the internal PNG formatting code - if this fails
+ * then the warning messages the library outputs will probably be garbage.
+ */
+static void
+perform_formatting_test(png_store *ps)
+{
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+   /* The handle into the formatting code is the RFC1123 support; this test does
+    * nothing if that is compiled out.
+    */
+   context(ps, fault);
+
+   Try
+   {
+      png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
+      png_const_charp result;
+#     if PNG_LIBPNG_VER >= 10600
+         char timestring[29];
+#     endif
+      png_structp pp;
+      png_time pt;
+
+      pp = set_store_for_write(ps, NULL, "libpng formatting test");
+
+      if (pp == NULL)
+         Throw ps;
+
+
+      /* Arbitrary settings: */
+      pt.year = 2079;
+      pt.month = 8;
+      pt.day = 29;
+      pt.hour = 13;
+      pt.minute = 53;
+      pt.second = 60; /* a leap second */
+
+#     if PNG_LIBPNG_VER < 10600
+         result = png_convert_to_rfc1123(pp, &pt);
+#     else
+         if (png_convert_to_rfc1123_buffer(timestring, &pt))
+            result = timestring;
+
+         else
+            result = NULL;
+#     endif
+
+      if (result == NULL)
+         png_error(pp, "png_convert_to_rfc1123 failed");
+
+      if (strcmp(result, correct) != 0)
+      {
+         size_t pos = 0;
+         char msg[128];
+
+         pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
+         pos = safecat(msg, sizeof msg, pos, correct);
+         pos = safecat(msg, sizeof msg, pos, ") returned: '");
+         pos = safecat(msg, sizeof msg, pos, result);
+         pos = safecat(msg, sizeof msg, pos, "'");
+
+         png_error(pp, msg);
+      }
+
+      store_write_reset(ps);
+   }
+
+   Catch(fault)
+   {
+      store_write_reset(fault);
+   }
+#else
+   UNUSED(ps)
+#endif
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* Because we want to use the same code in both the progressive reader and the
+ * sequential reader it is necessary to deal with the fact that the progressive
+ * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
+ * must contain all the test parameters and all the local variables directly
+ * accessible to the sequential reader implementation.
+ *
+ * The technique adopted is to reinvent part of what Dijkstra termed a
+ * 'display'; an array of pointers to the stack frames of enclosing functions so
+ * that a nested function definition can access the local (C auto) variables of
+ * the functions that contain its definition.  In fact C provides the first
+ * pointer (the local variables - the stack frame pointer) and the last (the
+ * global variables - the BCPL global vector typically implemented as global
+ * addresses), this code requires one more pointer to make the display - the
+ * local variables (and function call parameters) of the function that actually
+ * invokes either the progressive or sequential reader.
+ *
+ * Perhaps confusingly this technique is confounded with classes - the
+ * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
+ * A gamma_display is a standard_display, taking advantage of the ANSI-C
+ * requirement that the pointer to the first member of a structure must be the
+ * same as the pointer to the structure.  This allows us to reuse standard_
+ * functions in the gamma test code; something that could not be done with
+ * nested functions!
+ */
+typedef struct standard_display
+{
+   png_store*  ps;             /* Test parameters (passed to the function) */
+   png_byte    colour_type;
+   png_byte    bit_depth;
+   png_byte    red_sBIT;       /* Input data sBIT values. */
+   png_byte    green_sBIT;
+   png_byte    blue_sBIT;
+   png_byte    alpha_sBIT;
+   png_byte    interlace_type;
+   png_byte    filler;         /* Output has a filler */
+   png_uint_32 id;             /* Calculated file ID */
+   png_uint_32 w;              /* Width of image */
+   png_uint_32 h;              /* Height of image */
+   int         npasses;        /* Number of interlaced passes */
+   png_uint_32 pixel_size;     /* Width of one pixel in bits */
+   png_uint_32 bit_width;      /* Width of output row in bits */
+   size_t      cbRow;          /* Bytes in a row of the output image */
+   int         do_interlace;   /* Do interlacing internally */
+   int         littleendian;   /* App (row) data is little endian */
+   int         is_transparent; /* Transparency information was present. */
+   int         has_tRNS;       /* color type GRAY or RGB with a tRNS chunk. */
+   int         speed;          /* Doing a speed test */
+   int         use_update_info;/* Call update_info, not start_image */
+   struct
+   {
+      png_uint_16 red;
+      png_uint_16 green;
+      png_uint_16 blue;
+   }           transparent;    /* The transparent color, if set. */
+   int         npalette;       /* Number of entries in the palette. */
+   store_palette
+               palette;
+} standard_display;
+
+static void
+standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
+   int do_interlace, int use_update_info)
+{
+   memset(dp, 0, sizeof *dp);
+
+   dp->ps = ps;
+   dp->colour_type = COL_FROM_ID(id);
+   dp->bit_depth = DEPTH_FROM_ID(id);
+   if (dp->bit_depth < 1 || dp->bit_depth > 16)
+      internal_error(ps, "internal: bad bit depth");
+   if (dp->colour_type == 3)
+      dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
+   else
+      dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
+         dp->bit_depth;
+   dp->interlace_type = INTERLACE_FROM_ID(id);
+   check_interlace_type(dp->interlace_type);
+   dp->id = id;
+   /* All the rest are filled in after the read_info: */
+   dp->w = 0;
+   dp->h = 0;
+   dp->npasses = 0;
+   dp->pixel_size = 0;
+   dp->bit_width = 0;
+   dp->cbRow = 0;
+   dp->do_interlace = do_interlace;
+   dp->littleendian = 0;
+   dp->is_transparent = 0;
+   dp->speed = ps->speed;
+   dp->use_update_info = use_update_info;
+   dp->npalette = 0;
+   /* Preset the transparent color to black: */
+   memset(&dp->transparent, 0, sizeof dp->transparent);
+   /* Preset the palette to full intensity/opaque throughout: */
+   memset(dp->palette, 0xff, sizeof dp->palette);
+}
+
+/* Initialize the palette fields - this must be done later because the palette
+ * comes from the particular png_store_file that is selected.
+ */
+static void
+standard_palette_init(standard_display *dp)
+{
+   store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
+
+   /* The remaining entries remain white/opaque. */
+   if (dp->npalette > 0)
+   {
+      int i = dp->npalette;
+      memcpy(dp->palette, palette, i * sizeof *palette);
+
+      /* Check for a non-opaque palette entry: */
+      while (--i >= 0)
+         if (palette[i].alpha < 255)
+            break;
+
+#     ifdef __GNUC__
+         /* GCC can't handle the more obviously optimizable version. */
+         if (i >= 0)
+            dp->is_transparent = 1;
+         else
+            dp->is_transparent = 0;
+#     else
+         dp->is_transparent = (i >= 0);
+#     endif
+   }
+}
+
+/* Utility to read the palette from the PNG file and convert it into
+ * store_palette format.  This returns 1 if there is any transparency in the
+ * palette (it does not check for a transparent colour in the non-palette case.)
+ */
+static int
+read_palette(store_palette palette, int *npalette, png_const_structp pp,
+   png_infop pi)
+{
+   png_colorp pal;
+   png_bytep trans_alpha;
+   int num;
+
+   pal = 0;
+   *npalette = -1;
+
+   if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
+   {
+      int i = *npalette;
+
+      if (i <= 0 || i > 256)
+         png_error(pp, "validate: invalid PLTE count");
+
+      while (--i >= 0)
+      {
+         palette[i].red = pal[i].red;
+         palette[i].green = pal[i].green;
+         palette[i].blue = pal[i].blue;
+      }
+
+      /* Mark the remainder of the entries with a flag value (other than
+       * white/opaque which is the flag value stored above.)
+       */
+      memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
+   }
+
+   else /* !png_get_PLTE */
+   {
+      if (*npalette != (-1))
+         png_error(pp, "validate: invalid PLTE result");
+      /* But there is no palette, so record this: */
+      *npalette = 0;
+      memset(palette, 113, sizeof (store_palette));
+   }
+
+   trans_alpha = 0;
+   num = 2; /* force error below */
+   if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
+      (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
+      /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
+       * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
+       * so in the above call we get a success, we get a pointer (who knows what
+       * to) and we get num_trans == 0:
+       */
+      !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
+   {
+      int i;
+
+      /* Any of these are crash-worthy - given the implementation of
+       * png_get_tRNS up to 1.5 an app won't crash if it just checks the
+       * result above and fails to check that the variables it passed have
+       * actually been filled in!  Note that if the app were to pass the
+       * last, png_color_16p, variable too it couldn't rely on this.
+       */
+      if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
+         png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
+
+      for (i=0; i<num; ++i)
+         palette[i].alpha = trans_alpha[i];
+
+      for (num=*npalette; i<num; ++i)
+         palette[i].alpha = 255;
+
+      for (; i<256; ++i)
+         palette[i].alpha = 33; /* flag value */
+
+      return 1; /* transparency */
+   }
+
+   else
+   {
+      /* No palette transparency - just set the alpha channel to opaque. */
+      int i;
+
+      for (i=0, num=*npalette; i<num; ++i)
+         palette[i].alpha = 255;
+
+      for (; i<256; ++i)
+         palette[i].alpha = 55; /* flag value */
+
+      return 0; /* no transparency */
+   }
+}
+
+/* Utility to validate the palette if it should not have changed (the
+ * non-transform case).
+ */
+static void
+standard_palette_validate(standard_display *dp, png_const_structp pp,
+   png_infop pi)
+{
+   int npalette;
+   store_palette palette;
+
+   if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
+      png_error(pp, "validate: palette transparency changed");
+
+   if (npalette != dp->npalette)
+   {
+      size_t pos = 0;
+      char msg[64];
+
+      pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
+      pos = safecatn(msg, sizeof msg, pos, dp->npalette);
+      pos = safecat(msg, sizeof msg, pos, " -> ");
+      pos = safecatn(msg, sizeof msg, pos, npalette);
+      png_error(pp, msg);
+   }
+
+   {
+      int i = npalette; /* npalette is aliased */
+
+      while (--i >= 0)
+         if (palette[i].red != dp->palette[i].red ||
+            palette[i].green != dp->palette[i].green ||
+            palette[i].blue != dp->palette[i].blue ||
+            palette[i].alpha != dp->palette[i].alpha)
+            png_error(pp, "validate: PLTE or tRNS chunk changed");
+   }
+}
+
+/* By passing a 'standard_display' the progressive callbacks can be used
+ * directly by the sequential code, the functions suffixed "_imp" are the
+ * implementations, the functions without the suffix are the callbacks.
+ *
+ * The code for the info callback is split into two because this callback calls
+ * png_read_update_info or png_start_read_image and what gets called depends on
+ * whether the info needs updating (we want to test both calls in pngvalid.)
+ */
+static void
+standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
+{
+   if (png_get_bit_depth(pp, pi) != dp->bit_depth)
+      png_error(pp, "validate: bit depth changed");
+
+   if (png_get_color_type(pp, pi) != dp->colour_type)
+      png_error(pp, "validate: color type changed");
+
+   if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
+      png_error(pp, "validate: filter type changed");
+
+   if (png_get_interlace_type(pp, pi) != dp->interlace_type)
+      png_error(pp, "validate: interlacing changed");
+
+   if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
+      png_error(pp, "validate: compression type changed");
+
+   dp->w = png_get_image_width(pp, pi);
+
+   if (dp->w != standard_width(pp, dp->id))
+      png_error(pp, "validate: image width changed");
+
+   dp->h = png_get_image_height(pp, pi);
+
+   if (dp->h != standard_height(pp, dp->id))
+      png_error(pp, "validate: image height changed");
+
+   /* Record (but don't check at present) the input sBIT according to the colour
+    * type information.
+    */
+   {
+      png_color_8p sBIT = 0;
+
+      if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
+      {
+         int sBIT_invalid = 0;
+
+         if (sBIT == 0)
+            png_error(pp, "validate: unexpected png_get_sBIT result");
+
+         if (dp->colour_type & PNG_COLOR_MASK_COLOR)
+         {
+            if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->red_sBIT = sBIT->red;
+
+            if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->green_sBIT = sBIT->green;
+
+            if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->blue_sBIT = sBIT->blue;
+         }
+
+         else /* !COLOR */
+         {
+            if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
+         }
+
+         /* All 8 bits in tRNS for a palette image are significant - see the
+          * spec.
+          */
+         if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
+         {
+            if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->alpha_sBIT = sBIT->alpha;
+         }
+
+         if (sBIT_invalid)
+            png_error(pp, "validate: sBIT value out of range");
+      }
+   }
+
+   /* Important: this is validating the value *before* any transforms have been
+    * put in place.  It doesn't matter for the standard tests, where there are
+    * no transforms, but it does for other tests where rowbytes may change after
+    * png_read_update_info.
+    */
+   if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
+      png_error(pp, "validate: row size changed");
+
+   /* Validate the colour type 3 palette (this can be present on other color
+    * types.)
+    */
+   standard_palette_validate(dp, pp, pi);
+
+   /* In any case always check for a transparent color (notice that the
+    * colour type 3 case must not give a successful return on the get_tRNS call
+    * with these arguments!)
+    */
+   {
+      png_color_16p trans_color = 0;
+
+      if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
+      {
+         if (trans_color == 0)
+            png_error(pp, "validate: unexpected png_get_tRNS (color) result");
+
+         switch (dp->colour_type)
+         {
+         case 0:
+            dp->transparent.red = dp->transparent.green = dp->transparent.blue =
+               trans_color->gray;
+            dp->has_tRNS = 1;
+            break;
+
+         case 2:
+            dp->transparent.red = trans_color->red;
+            dp->transparent.green = trans_color->green;
+            dp->transparent.blue = trans_color->blue;
+            dp->has_tRNS = 1;
+            break;
+
+         case 3:
+            /* Not expected because it should result in the array case
+             * above.
+             */
+            png_error(pp, "validate: unexpected png_get_tRNS result");
+            break;
+
+         default:
+            png_error(pp, "validate: invalid tRNS chunk with alpha image");
+         }
+      }
+   }
+
+   /* Read the number of passes - expected to match the value used when
+    * creating the image (interlaced or not).  This has the side effect of
+    * turning on interlace handling (if do_interlace is not set.)
+    */
+   dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
+   if (!dp->do_interlace)
+   {
+#     ifdef PNG_READ_INTERLACING_SUPPORTED
+         if (dp->npasses != png_set_interlace_handling(pp))
+            png_error(pp, "validate: file changed interlace type");
+#     else /* !READ_INTERLACING */
+         /* This should never happen: the relevant tests (!do_interlace) should
+          * not be run.
+          */
+         if (dp->npasses > 1)
+            png_error(pp, "validate: no libpng interlace support");
+#     endif /* !READ_INTERLACING */
+   }
+
+   /* Caller calls png_read_update_info or png_start_read_image now, then calls
+    * part2.
+    */
+}
+
+/* This must be called *after* the png_read_update_info call to get the correct
+ * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
+ * image.
+ */
+static void
+standard_info_part2(standard_display *dp, png_const_structp pp,
+    png_const_infop pi, int nImages)
+{
+   /* Record cbRow now that it can be found. */
+   {
+      png_byte ct = png_get_color_type(pp, pi);
+      png_byte bd = png_get_bit_depth(pp, pi);
+
+      if (bd >= 8 && (ct == PNG_COLOR_TYPE_RGB || ct == PNG_COLOR_TYPE_GRAY) &&
+          dp->filler)
+          ct |= 4; /* handle filler as faked alpha channel */
+
+      dp->pixel_size = bit_size(pp, ct, bd);
+   }
+   dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
+   dp->cbRow = png_get_rowbytes(pp, pi);
+
+   /* Validate the rowbytes here again. */
+   if (dp->cbRow != (dp->bit_width+7)/8)
+      png_error(pp, "bad png_get_rowbytes calculation");
+
+   /* Then ensure there is enough space for the output image(s). */
+   store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
+}
+
+static void
+standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
+    int nImages)
+{
+   /* Note that the validation routine has the side effect of turning on
+    * interlace handling in the subsequent code.
+    */
+   standard_info_part1(dp, pp, pi);
+
+   /* And the info callback has to call this (or png_read_update_info - see
+    * below in the png_modifier code for that variant.
+    */
+   if (dp->use_update_info)
+   {
+      /* For debugging the effect of multiple calls: */
+      int i = dp->use_update_info;
+      while (i-- > 0)
+         png_read_update_info(pp, pi);
+   }
+
+   else
+      png_start_read_image(pp);
+
+   /* Validate the height, width and rowbytes plus ensure that sufficient buffer
+    * exists for decoding the image.
+    */
+   standard_info_part2(dp, pp, pi, nImages);
+}
+
+static void PNGCBAPI
+standard_info(png_structp pp, png_infop pi)
+{
+   standard_display *dp = voidcast(standard_display*,
+      png_get_progressive_ptr(pp));
+
+   /* Call with nImages==1 because the progressive reader can only produce one
+    * image.
+    */
+   standard_info_imp(dp, pp, pi, 1 /*only one image*/);
+}
+
+static void PNGCBAPI
+progressive_row(png_structp ppIn, png_bytep new_row, png_uint_32 y, int pass)
+{
+   png_const_structp pp = ppIn;
+   const standard_display *dp = voidcast(standard_display*,
+      png_get_progressive_ptr(pp));
+
+   /* When handling interlacing some rows will be absent in each pass, the
+    * callback still gets called, but with a NULL pointer.  This is checked
+    * in the 'else' clause below.  We need our own 'cbRow', but we can't call
+    * png_get_rowbytes because we got no info structure.
+    */
+   if (new_row != NULL)
+   {
+      png_bytep row;
+
+      /* In the case where the reader doesn't do the interlace it gives
+       * us the y in the sub-image:
+       */
+      if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
+      {
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+         /* Use this opportunity to validate the png 'current' APIs: */
+         if (y != png_get_current_row_number(pp))
+            png_error(pp, "png_get_current_row_number is broken");
+
+         if (pass != png_get_current_pass_number(pp))
+            png_error(pp, "png_get_current_pass_number is broken");
+#endif /* USER_TRANSFORM_INFO */
+
+         y = PNG_ROW_FROM_PASS_ROW(y, pass);
+      }
+
+      /* Validate this just in case. */
+      if (y >= dp->h)
+         png_error(pp, "invalid y to progressive row callback");
+
+      row = store_image_row(dp->ps, pp, 0, y);
+
+      /* Combine the new row into the old: */
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+      if (dp->do_interlace)
+#endif /* READ_INTERLACING */
+      {
+         if (dp->interlace_type == PNG_INTERLACE_ADAM7)
+            deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass,
+                  dp->littleendian);
+         else
+            row_copy(row, new_row, dp->pixel_size * dp->w, dp->littleendian);
+      }
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+      else
+         png_progressive_combine_row(pp, row, new_row);
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+   }
+
+   else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
+       PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
+       PNG_PASS_COLS(dp->w, pass) > 0)
+      png_error(pp, "missing row in progressive de-interlacing");
+}
+
+static void
+sequential_row(standard_display *dp, png_structp pp, png_infop pi,
+    int iImage, int iDisplay)
+{
+   int npasses = dp->npasses;
+   int do_interlace = dp->do_interlace &&
+      dp->interlace_type == PNG_INTERLACE_ADAM7;
+   png_uint_32 height = standard_height(pp, dp->id);
+   png_uint_32 width = standard_width(pp, dp->id);
+   const png_store* ps = dp->ps;
+   int pass;
+
+   for (pass=0; pass<npasses; ++pass)
+   {
+      png_uint_32 y;
+      png_uint_32 wPass = PNG_PASS_COLS(width, pass);
+
+      for (y=0; y<height; ++y)
+      {
+         if (do_interlace)
+         {
+            /* wPass may be zero or this row may not be in this pass.
+             * png_read_row must not be called in either case.
+             */
+            if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
+            {
+               /* Read the row into a pair of temporary buffers, then do the
+                * merge here into the output rows.
+                */
+               png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
+
+               /* The following aids (to some extent) error detection - we can
+                * see where png_read_row wrote.  Use opposite values in row and
+                * display to make this easier.  Don't use 0xff (which is used in
+                * the image write code to fill unused bits) or 0 (which is a
+                * likely value to overwrite unused bits with).
+                */
+               memset(row, 0xc5, sizeof row);
+               memset(display, 0x5c, sizeof display);
+
+               png_read_row(pp, row, display);
+
+               if (iImage >= 0)
+                  deinterlace_row(store_image_row(ps, pp, iImage, y), row,
+                     dp->pixel_size, dp->w, pass, dp->littleendian);
+
+               if (iDisplay >= 0)
+                  deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
+                     dp->pixel_size, dp->w, pass, dp->littleendian);
+            }
+         }
+         else
+            png_read_row(pp,
+               iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
+               iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
+      }
+   }
+
+   /* And finish the read operation (only really necessary if the caller wants
+    * to find additional data in png_info from chunks after the last IDAT.)
+    */
+   png_read_end(pp, pi);
+}
+
+#ifdef PNG_TEXT_SUPPORTED
+static void
+standard_check_text(png_const_structp pp, png_const_textp tp,
+   png_const_charp keyword, png_const_charp text)
+{
+   char msg[1024];
+   size_t pos = safecat(msg, sizeof msg, 0, "text: ");
+   size_t ok;
+
+   pos = safecat(msg, sizeof msg, pos, keyword);
+   pos = safecat(msg, sizeof msg, pos, ": ");
+   ok = pos;
+
+   if (tp->compression != TEXT_COMPRESSION)
+   {
+      char buf[64];
+
+      sprintf(buf, "compression [%d->%d], ", TEXT_COMPRESSION,
+         tp->compression);
+      pos = safecat(msg, sizeof msg, pos, buf);
+   }
+
+   if (tp->key == NULL || strcmp(tp->key, keyword) != 0)
+   {
+      pos = safecat(msg, sizeof msg, pos, "keyword \"");
+      if (tp->key != NULL)
+      {
+         pos = safecat(msg, sizeof msg, pos, tp->key);
+         pos = safecat(msg, sizeof msg, pos, "\", ");
+      }
+
+      else
+         pos = safecat(msg, sizeof msg, pos, "null, ");
+   }
+
+   if (tp->text == NULL)
+      pos = safecat(msg, sizeof msg, pos, "text lost, ");
+
+   else
+   {
+      if (tp->text_length != strlen(text))
+      {
+         char buf[64];
+         sprintf(buf, "text length changed[%lu->%lu], ",
+            (unsigned long)strlen(text), (unsigned long)tp->text_length);
+         pos = safecat(msg, sizeof msg, pos, buf);
+      }
+
+      if (strcmp(tp->text, text) != 0)
+      {
+         pos = safecat(msg, sizeof msg, pos, "text becomes \"");
+         pos = safecat(msg, sizeof msg, pos, tp->text);
+         pos = safecat(msg, sizeof msg, pos, "\" (was \"");
+         pos = safecat(msg, sizeof msg, pos, text);
+         pos = safecat(msg, sizeof msg, pos, "\"), ");
+      }
+   }
+
+   if (tp->itxt_length != 0)
+      pos = safecat(msg, sizeof msg, pos, "iTXt length set, ");
+
+   if (tp->lang != NULL)
+   {
+      pos = safecat(msg, sizeof msg, pos, "iTXt language \"");
+      pos = safecat(msg, sizeof msg, pos, tp->lang);
+      pos = safecat(msg, sizeof msg, pos, "\", ");
+   }
+
+   if (tp->lang_key != NULL)
+   {
+      pos = safecat(msg, sizeof msg, pos, "iTXt keyword \"");
+      pos = safecat(msg, sizeof msg, pos, tp->lang_key);
+      pos = safecat(msg, sizeof msg, pos, "\", ");
+   }
+
+   if (pos > ok)
+   {
+      msg[pos-2] = '\0'; /* Remove the ", " at the end */
+      png_error(pp, msg);
+   }
+}
+
+static void
+standard_text_validate(standard_display *dp, png_const_structp pp,
+   png_infop pi, int check_end)
+{
+   png_textp tp = NULL;
+   png_uint_32 num_text = png_get_text(pp, pi, &tp, NULL);
+
+   if (num_text == 2 && tp != NULL)
+   {
+      standard_check_text(pp, tp, "image name", dp->ps->current->name);
+
+      /* This exists because prior to 1.5.18 the progressive reader left the
+       * png_struct z_stream unreset at the end of the image, so subsequent
+       * attempts to use it simply returns Z_STREAM_END.
+       */
+      if (check_end)
+         standard_check_text(pp, tp+1, "end marker", "end");
+   }
+
+   else
+   {
+      char msg[64];
+
+      sprintf(msg, "expected two text items, got %lu",
+         (unsigned long)num_text);
+      png_error(pp, msg);
+   }
+}
+#else
+#  define standard_text_validate(dp,pp,pi,check_end) ((void)0)
+#endif
+
+static void
+standard_row_validate(standard_display *dp, png_const_structp pp,
+   int iImage, int iDisplay, png_uint_32 y)
+{
+   int where;
+   png_byte std[STANDARD_ROWMAX];
+
+   /* The row must be pre-initialized to the magic number here for the size
+    * tests to pass:
+    */
+   memset(std, 178, sizeof std);
+   standard_row(pp, std, dp->id, y);
+
+   /* At the end both the 'row' and 'display' arrays should end up identical.
+    * In earlier passes 'row' will be partially filled in, with only the pixels
+    * that have been read so far, but 'display' will have those pixels
+    * replicated to fill the unread pixels while reading an interlaced image.
+    */
+   if (iImage >= 0 &&
+      (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
+            dp->bit_width)) != 0)
+   {
+      char msg[64];
+      sprintf(msg, "PNG image row[%lu][%d] changed from %.2x to %.2x",
+         (unsigned long)y, where-1, std[where-1],
+         store_image_row(dp->ps, pp, iImage, y)[where-1]);
+      png_error(pp, msg);
+   }
+
+   if (iDisplay >= 0 &&
+      (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
+         dp->bit_width)) != 0)
+   {
+      char msg[64];
+      sprintf(msg, "display row[%lu][%d] changed from %.2x to %.2x",
+         (unsigned long)y, where-1, std[where-1],
+         store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
+      png_error(pp, msg);
+   }
+}
+
+static void
+standard_image_validate(standard_display *dp, png_const_structp pp, int iImage,
+    int iDisplay)
+{
+   png_uint_32 y;
+
+   if (iImage >= 0)
+      store_image_check(dp->ps, pp, iImage);
+
+   if (iDisplay >= 0)
+      store_image_check(dp->ps, pp, iDisplay);
+
+   for (y=0; y<dp->h; ++y)
+      standard_row_validate(dp, pp, iImage, iDisplay, y);
+
+   /* This avoids false positives if the validation code is never called! */
+   dp->ps->validated = 1;
+}
+
+static void PNGCBAPI
+standard_end(png_structp ppIn, png_infop pi)
+{
+   png_const_structp pp = ppIn;
+   standard_display *dp = voidcast(standard_display*,
+      png_get_progressive_ptr(pp));
+
+   UNUSED(pi)
+
+   /* Validate the image - progressive reading only produces one variant for
+    * interlaced images.
+    */
+   standard_text_validate(dp, pp, pi,
+      PNG_LIBPNG_VER >= 10518/*check_end: see comments above*/);
+   standard_image_validate(dp, pp, 0, -1);
+}
+
+/* A single test run checking the standard image to ensure it is not damaged. */
+static void
+standard_test(png_store* const psIn, png_uint_32 const id,
+   int do_interlace, int use_update_info)
+{
+   standard_display d;
+   context(psIn, fault);
+
+   /* Set up the display (stack frame) variables from the arguments to the
+    * function and initialize the locals that are filled in later.
+    */
+   standard_display_init(&d, psIn, id, do_interlace, use_update_info);
+
+   /* Everything is protected by a Try/Catch.  The functions called also
+    * typically have local Try/Catch blocks.
+    */
+   Try
+   {
+      png_structp pp;
+      png_infop pi;
+
+      /* Get a png_struct for reading the image. This will throw an error if it
+       * fails, so we don't need to check the result.
+       */
+      pp = set_store_for_read(d.ps, &pi, d.id,
+         d.do_interlace ?  (d.ps->progressive ?
+            "pngvalid progressive deinterlacer" :
+            "pngvalid sequential deinterlacer") : (d.ps->progressive ?
+               "progressive reader" : "sequential reader"));
+
+      /* Initialize the palette correctly from the png_store_file. */
+      standard_palette_init(&d);
+
+      /* Introduce the correct read function. */
+      if (d.ps->progressive)
+      {
+         png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
+            standard_end);
+
+         /* Now feed data into the reader until we reach the end: */
+         store_progressive_read(d.ps, pp, pi);
+      }
+      else
+      {
+         /* Note that this takes the store, not the display. */
+         png_set_read_fn(pp, d.ps, store_read);
+
+         /* Check the header values: */
+         png_read_info(pp, pi);
+
+         /* The code tests both versions of the images that the sequential
+          * reader can produce.
+          */
+         standard_info_imp(&d, pp, pi, 2 /*images*/);
+
+         /* Need the total bytes in the image below; we can't get to this point
+          * unless the PNG file values have been checked against the expected
+          * values.
+          */
+         {
+            sequential_row(&d, pp, pi, 0, 1);
+
+            /* After the last pass loop over the rows again to check that the
+             * image is correct.
+             */
+            if (!d.speed)
+            {
+               standard_text_validate(&d, pp, pi, 1/*check_end*/);
+               standard_image_validate(&d, pp, 0, 1);
+            }
+            else
+               d.ps->validated = 1;
+         }
+      }
+
+      /* Check for validation. */
+      if (!d.ps->validated)
+         png_error(pp, "image read failed silently");
+
+      /* Successful completion. */
+   }
+
+   Catch(fault)
+      d.ps = fault; /* make sure this hasn't been clobbered. */
+
+   /* In either case clean up the store. */
+   store_read_reset(d.ps);
+}
+
+static int
+test_standard(png_modifier* const pm, png_byte const colour_type,
+    int bdlo, int const bdhi)
+{
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      int interlace_type;
+
+      for (interlace_type = PNG_INTERLACE_NONE;
+           interlace_type < INTERLACE_LAST; ++interlace_type)
+      {
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            interlace_type, 0, 0, 0), do_read_interlace, pm->use_update_info);
+
+         if (fail(pm))
+            return 0;
+      }
+   }
+
+   return 1; /* keep going */
+}
+
+static void
+perform_standard_test(png_modifier *pm)
+{
+   /* Test each colour type over the valid range of bit depths (expressed as
+    * log2(bit_depth) in turn, stop as soon as any error is detected.
+    */
+   if (!test_standard(pm, 0, 0, READ_BDHI))
+      return;
+
+   if (!test_standard(pm, 2, 3, READ_BDHI))
+      return;
+
+   if (!test_standard(pm, 3, 0, 3))
+      return;
+
+   if (!test_standard(pm, 4, 3, READ_BDHI))
+      return;
+
+   if (!test_standard(pm, 6, 3, READ_BDHI))
+      return;
+}
+
+
+/********************************** SIZE TESTS ********************************/
+static int
+test_size(png_modifier* const pm, png_byte const colour_type,
+    int bdlo, int const bdhi)
+{
+   /* Run the tests on each combination.
+    *
+    * NOTE: on my 32 bit x86 each of the following blocks takes
+    * a total of 3.5 seconds if done across every combo of bit depth
+    * width and height.  This is a waste of time in practice, hence the
+    * hinc and winc stuff:
+    */
+   static const png_byte hinc[] = {1, 3, 11, 1, 5};
+   static const png_byte winc[] = {1, 9, 5, 7, 1};
+   int save_bdlo = bdlo;
+
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      png_uint_32 h, w;
+
+      for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
+      {
+         /* First test all the 'size' images against the sequential
+          * reader using libpng to deinterlace (where required.)  This
+          * validates the write side of libpng.  There are four possibilities
+          * to validate.
+          */
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
+            pm->use_update_info);
+
+         if (fail(pm))
+            return 0;
+
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
+            pm->use_update_info);
+
+         if (fail(pm))
+            return 0;
+
+         /* Now validate the interlaced read side - do_interlace true,
+          * in the progressive case this does actually make a difference
+          * to the code used in the non-interlaced case too.
+          */
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
+            pm->use_update_info);
+
+         if (fail(pm))
+            return 0;
+
+#     if CAN_WRITE_INTERLACE
+         /* Validate the pngvalid code itself: */
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_ADAM7, w, h, 1), 1/*do_interlace*/,
+            pm->use_update_info);
+
+         if (fail(pm))
+            return 0;
+#     endif
+      }
+   }
+
+   /* Now do the tests of libpng interlace handling, after we have made sure
+    * that the pngvalid version works:
+    */
+   for (bdlo = save_bdlo; bdlo <= bdhi; ++bdlo)
+   {
+      png_uint_32 h, w;
+
+      for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
+      {
+#     ifdef PNG_READ_INTERLACING_SUPPORTED
+         /* Test with pngvalid generated interlaced images first; we have
+          * already verify these are ok (unless pngvalid has self-consistent
+          * read/write errors, which is unlikely), so this detects errors in the
+          * read side first:
+          */
+#     if CAN_WRITE_INTERLACE
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
+            pm->use_update_info);
+
+         if (fail(pm))
+            return 0;
+#     endif
+#     endif /* READ_INTERLACING */
+
+#     ifdef PNG_WRITE_INTERLACING_SUPPORTED
+         /* Test the libpng write side against the pngvalid read side: */
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
+            pm->use_update_info);
+
+         if (fail(pm))
+            return 0;
+#     endif
+
+#     ifdef PNG_READ_INTERLACING_SUPPORTED
+#     ifdef PNG_WRITE_INTERLACING_SUPPORTED
+         /* Test both together: */
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
+            pm->use_update_info);
+
+         if (fail(pm))
+            return 0;
+#     endif
+#     endif /* READ_INTERLACING */
+      }
+   }
+
+   return 1; /* keep going */
+}
+
+static void
+perform_size_test(png_modifier *pm)
+{
+   /* Test each colour type over the valid range of bit depths (expressed as
+    * log2(bit_depth) in turn, stop as soon as any error is detected.
+    */
+   if (!test_size(pm, 0, 0, READ_BDHI))
+      return;
+
+   if (!test_size(pm, 2, 3, READ_BDHI))
+      return;
+
+   /* For the moment don't do the palette test - it's a waste of time when
+    * compared to the grayscale test.
+    */
+#if 0
+   if (!test_size(pm, 3, 0, 3))
+      return;
+#endif
+
+   if (!test_size(pm, 4, 3, READ_BDHI))
+      return;
+
+   if (!test_size(pm, 6, 3, READ_BDHI))
+      return;
+}
+
+
+/******************************* TRANSFORM TESTS ******************************/
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* A set of tests to validate libpng image transforms.  The possibilities here
+ * are legion because the transforms can be combined in a combinatorial
+ * fashion.  To deal with this some measure of restraint is required, otherwise
+ * the tests would take forever.
+ */
+typedef struct image_pixel
+{
+   /* A local (pngvalid) representation of a PNG pixel, in all its
+    * various forms.
+    */
+   unsigned int red, green, blue, alpha; /* For non-palette images. */
+   unsigned int palette_index;           /* For a palette image. */
+   png_byte     colour_type;             /* As in the spec. */
+   png_byte     bit_depth;               /* Defines bit size in row */
+   png_byte     sample_depth;            /* Scale of samples */
+   unsigned int have_tRNS :1;            /* tRNS chunk may need processing */
+   unsigned int swap_rgb :1;             /* RGB swapped to BGR */
+   unsigned int alpha_first :1;          /* Alpha at start, not end */
+   unsigned int alpha_inverted :1;       /* Alpha channel inverted */
+   unsigned int mono_inverted :1;        /* Gray channel inverted */
+   unsigned int swap16 :1;               /* Byte swap 16-bit components */
+   unsigned int littleendian :1;         /* High bits on right */
+   unsigned int sig_bits :1;             /* Pixel shifted (sig bits only) */
+
+   /* For checking the code calculates double precision floating point values
+    * along with an error value, accumulated from the transforms.  Because an
+    * sBIT setting allows larger error bounds (indeed, by the spec, apparently
+    * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
+    * channel is stored.  This sBIT value is folded in to the stored error value
+    * at the end of the application of the transforms to the pixel.
+    *
+    * If sig_bits is set above the red, green, blue and alpha values have been
+    * scaled so they only contain the significant bits of the component values.
+    */
+   double   redf, greenf, bluef, alphaf;
+   double   rede, greene, bluee, alphae;
+   png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
+} image_pixel;
+
+/* Shared utility function, see below. */
+static void
+image_pixel_setf(image_pixel *this, unsigned int rMax, unsigned int gMax,
+        unsigned int bMax, unsigned int aMax)
+{
+   this->redf = this->red / (double)rMax;
+   this->greenf = this->green / (double)gMax;
+   this->bluef = this->blue / (double)bMax;
+   this->alphaf = this->alpha / (double)aMax;
+
+   if (this->red < rMax)
+      this->rede = this->redf * DBL_EPSILON;
+   else
+      this->rede = 0;
+   if (this->green < gMax)
+      this->greene = this->greenf * DBL_EPSILON;
+   else
+      this->greene = 0;
+   if (this->blue < bMax)
+      this->bluee = this->bluef * DBL_EPSILON;
+   else
+      this->bluee = 0;
+   if (this->alpha < aMax)
+      this->alphae = this->alphaf * DBL_EPSILON;
+   else
+      this->alphae = 0;
+}
+
+/* Initialize the structure for the next pixel - call this before doing any
+ * transforms and call it for each pixel since all the fields may need to be
+ * reset.
+ */
+static void
+image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
+    png_byte bit_depth, png_uint_32 x, store_palette palette,
+    const image_pixel *format /*from pngvalid transform of input*/)
+{
+   png_byte sample_depth =
+      (png_byte)(colour_type == PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
+   unsigned int max = (1U<<sample_depth)-1;
+   int swap16 = (format != 0 && format->swap16);
+   int littleendian = (format != 0 && format->littleendian);
+   int sig_bits = (format != 0 && format->sig_bits);
+
+   /* Initially just set everything to the same number and the alpha to opaque.
+    * Note that this currently assumes a simple palette where entry x has colour
+    * rgb(x,x,x)!
+    */
+   this->palette_index = this->red = this->green = this->blue =
+      sample(row, colour_type, bit_depth, x, 0, swap16, littleendian);
+   this->alpha = max;
+   this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
+      sample_depth;
+
+   /* Then override as appropriate: */
+   if (colour_type == 3) /* palette */
+   {
+      /* This permits the caller to default to the sample value. */
+      if (palette != 0)
+      {
+         unsigned int i = this->palette_index;
+
+         this->red = palette[i].red;
+         this->green = palette[i].green;
+         this->blue = palette[i].blue;
+         this->alpha = palette[i].alpha;
+      }
+   }
+
+   else /* not palette */
+   {
+      unsigned int i = 0;
+
+      if ((colour_type & 4) != 0 && format != 0 && format->alpha_first)
+      {
+         this->alpha = this->red;
+         /* This handles the gray case for 'AG' pixels */
+         this->palette_index = this->red = this->green = this->blue =
+            sample(row, colour_type, bit_depth, x, 1, swap16, littleendian);
+         i = 1;
+      }
+
+      if (colour_type & 2)
+      {
+         /* Green is second for both BGR and RGB: */
+         this->green = sample(row, colour_type, bit_depth, x, ++i, swap16,
+                 littleendian);
+
+         if (format != 0 && format->swap_rgb) /* BGR */
+             this->red = sample(row, colour_type, bit_depth, x, ++i, swap16,
+                     littleendian);
+         else
+             this->blue = sample(row, colour_type, bit_depth, x, ++i, swap16,
+                     littleendian);
+      }
+
+      else /* grayscale */ if (format != 0 && format->mono_inverted)
+         this->red = this->green = this->blue = this->red ^ max;
+
+      if ((colour_type & 4) != 0) /* alpha */
+      {
+         if (format == 0 || !format->alpha_first)
+             this->alpha = sample(row, colour_type, bit_depth, x, ++i, swap16,
+                     littleendian);
+
+         if (format != 0 && format->alpha_inverted)
+            this->alpha ^= max;
+      }
+   }
+
+   /* Calculate the scaled values, these are simply the values divided by
+    * 'max' and the error is initialized to the double precision epsilon value
+    * from the header file.
+    */
+   image_pixel_setf(this,
+      sig_bits ? (1U << format->red_sBIT)-1 : max,
+      sig_bits ? (1U << format->green_sBIT)-1 : max,
+      sig_bits ? (1U << format->blue_sBIT)-1 : max,
+      sig_bits ? (1U << format->alpha_sBIT)-1 : max);
+
+   /* Store the input information for use in the transforms - these will
+    * modify the information.
+    */
+   this->colour_type = colour_type;
+   this->bit_depth = bit_depth;
+   this->sample_depth = sample_depth;
+   this->have_tRNS = 0;
+   this->swap_rgb = 0;
+   this->alpha_first = 0;
+   this->alpha_inverted = 0;
+   this->mono_inverted = 0;
+   this->swap16 = 0;
+   this->littleendian = 0;
+   this->sig_bits = 0;
+}
+
+#if defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_GRAY_TO_RGB_SUPPORTED\
+   || defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_EXPAND_16_SUPPORTED\
+   || defined PNG_READ_BACKGROUND_SUPPORTED
+/* Convert a palette image to an rgb image.  This necessarily converts the tRNS
+ * chunk at the same time, because the tRNS will be in palette form.  The way
+ * palette validation works means that the original palette is never updated,
+ * instead the image_pixel value from the row contains the RGB of the
+ * corresponding palette entry and *this* is updated.  Consequently this routine
+ * only needs to change the colour type information.
+ */
+static void
+image_pixel_convert_PLTE(image_pixel *this)
+{
+   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (this->have_tRNS)
+      {
+         this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+         this->have_tRNS = 0;
+      }
+      else
+         this->colour_type = PNG_COLOR_TYPE_RGB;
+
+      /* The bit depth of the row changes at this point too (notice that this is
+       * the row format, not the sample depth, which is separate.)
+       */
+      this->bit_depth = 8;
+   }
+}
+
+/* Add an alpha channel; this will import the tRNS information because tRNS is
+ * not valid in an alpha image.  The bit depth will invariably be set to at
+ * least 8 prior to 1.7.0.  Palette images will be converted to alpha (using
+ * the above API).  With png_set_background the alpha channel is never expanded
+ * but this routine is used by pngvalid to simplify code; 'for_background'
+ * records this.
+ */
+static void
+image_pixel_add_alpha(image_pixel *this, const standard_display *display,
+   int for_background)
+{
+   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(this);
+
+   if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
+   {
+      if (this->colour_type == PNG_COLOR_TYPE_GRAY)
+      {
+#        if PNG_LIBPNG_VER < 10700
+            if (!for_background && this->bit_depth < 8)
+               this->bit_depth = this->sample_depth = 8;
+#        endif
+
+         if (this->have_tRNS)
+         {
+            /* After 1.7 the expansion of bit depth only happens if there is a
+             * tRNS chunk to expand at this point.
+             */
+#           if PNG_LIBPNG_VER >= 10700
+               if (!for_background && this->bit_depth < 8)
+                  this->bit_depth = this->sample_depth = 8;
+#           endif
+
+            this->have_tRNS = 0;
+
+            /* Check the input, original, channel value here against the
+             * original tRNS gray chunk valie.
+             */
+            if (this->red == display->transparent.red)
+               this->alphaf = 0;
+            else
+               this->alphaf = 1;
+         }
+         else
+            this->alphaf = 1;
+
+         this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+      }
+
+      else if (this->colour_type == PNG_COLOR_TYPE_RGB)
+      {
+         if (this->have_tRNS)
+         {
+            this->have_tRNS = 0;
+
+            /* Again, check the exact input values, not the current transformed
+             * value!
+             */
+            if (this->red == display->transparent.red &&
+               this->green == display->transparent.green &&
+               this->blue == display->transparent.blue)
+               this->alphaf = 0;
+            else
+               this->alphaf = 1;
+         }
+         else
+            this->alphaf = 1;
+
+         this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+      }
+
+      /* The error in the alpha is zero and the sBIT value comes from the
+       * original sBIT data (actually it will always be the original bit depth).
+       */
+      this->alphae = 0;
+      this->alpha_sBIT = display->alpha_sBIT;
+   }
+}
+#endif /* transforms that need image_pixel_add_alpha */
+
+struct transform_display;
+typedef struct image_transform
+{
+   /* The name of this transform: a string. */
+   const char *name;
+
+   /* Each transform can be disabled from the command line: */
+   int enable;
+
+   /* The global list of transforms; read only. */
+   struct image_transform *const list;
+
+   /* The global count of the number of times this transform has been set on an
+    * image.
+    */
+   unsigned int global_use;
+
+   /* The local count of the number of times this transform has been set. */
+   unsigned int local_use;
+
+   /* The next transform in the list, each transform must call its own next
+    * transform after it has processed the pixel successfully.
+    */
+   const struct image_transform *next;
+
+   /* A single transform for the image, expressed as a series of function
+    * callbacks and some space for values.
+    *
+    * First a callback to add any required modifications to the png_modifier;
+    * this gets called just before the modifier is set up for read.
+    */
+   void (*ini)(const struct image_transform *this,
+      struct transform_display *that);
+
+   /* And a callback to set the transform on the current png_read_struct:
+    */
+   void (*set)(const struct image_transform *this,
+      struct transform_display *that, png_structp pp, png_infop pi);
+
+   /* Then a transform that takes an input pixel in one PNG format or another
+    * and modifies it by a pngvalid implementation of the transform (thus
+    * duplicating the libpng intent without, we hope, duplicating the bugs
+    * in the libpng implementation!)  The png_structp is solely to allow error
+    * reporting via png_error and png_warning.
+    */
+   void (*mod)(const struct image_transform *this, image_pixel *that,
+      png_const_structp pp, const struct transform_display *display);
+
+   /* Add this transform to the list and return true if the transform is
+    * meaningful for this colour type and bit depth - if false then the
+    * transform should have no effect on the image so there's not a lot of
+    * point running it.
+    */
+   int (*add)(struct image_transform *this,
+      const struct image_transform **that, png_byte colour_type,
+      png_byte bit_depth);
+} image_transform;
+
+typedef struct transform_display
+{
+   standard_display this;
+
+   /* Parameters */
+   png_modifier*              pm;
+   const image_transform* transform_list;
+   unsigned int max_gamma_8;
+
+   /* Local variables */
+   png_byte output_colour_type;
+   png_byte output_bit_depth;
+   png_byte unpacked;
+
+   /* Modifications (not necessarily used.) */
+   gama_modification gama_mod;
+   chrm_modification chrm_mod;
+   srgb_modification srgb_mod;
+} transform_display;
+
+/* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
+static void
+transform_set_encoding(transform_display *this)
+{
+   /* Set up the png_modifier '_current' fields then use these to determine how
+    * to add appropriate chunks.
+    */
+   png_modifier *pm = this->pm;
+
+   modifier_set_encoding(pm);
+
+   if (modifier_color_encoding_is_set(pm))
+   {
+      if (modifier_color_encoding_is_sRGB(pm))
+         srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
+
+      else
+      {
+         /* Set gAMA and cHRM separately. */
+         gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
+
+         if (pm->current_encoding != 0)
+            chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
+      }
+   }
+}
+
+/* Three functions to end the list: */
+static void
+image_transform_ini_end(const image_transform *this,
+   transform_display *that)
+{
+   UNUSED(this)
+   UNUSED(that)
+}
+
+static void
+image_transform_set_end(const image_transform *this,
+   transform_display *that, png_structp pp, png_infop pi)
+{
+   UNUSED(this)
+   UNUSED(that)
+   UNUSED(pp)
+   UNUSED(pi)
+}
+
+/* At the end of the list recalculate the output image pixel value from the
+ * double precision values set up by the preceding 'mod' calls:
+ */
+static unsigned int
+sample_scale(double sample_value, unsigned int scale)
+{
+   sample_value = floor(sample_value * scale + .5);
+
+   /* Return NaN as 0: */
+   if (!(sample_value > 0))
+      sample_value = 0;
+   else if (sample_value > scale)
+      sample_value = scale;
+
+   return (unsigned int)sample_value;
+}
+
+static void
+image_transform_mod_end(const image_transform *this, image_pixel *that,
+    png_const_structp pp, const transform_display *display)
+{
+   unsigned int scale = (1U<<that->sample_depth)-1;
+   int sig_bits = that->sig_bits;
+
+   UNUSED(this)
+   UNUSED(pp)
+   UNUSED(display)
+
+   /* At the end recalculate the digitized red green and blue values according
+    * to the current sample_depth of the pixel.
+    *
+    * The sample value is simply scaled to the maximum, checking for over
+    * and underflow (which can both happen for some image transforms,
+    * including simple size scaling, though libpng doesn't do that at present.
+    */
+   that->red = sample_scale(that->redf, scale);
+
+   /* This is a bit bogus; really the above calculation should use the red_sBIT
+    * value, not sample_depth, but because libpng does png_set_shift by just
+    * shifting the bits we get errors if we don't do it the same way.
+    */
+   if (sig_bits && that->red_sBIT < that->sample_depth)
+      that->red >>= that->sample_depth - that->red_sBIT;
+
+   /* The error value is increased, at the end, according to the lowest sBIT
+    * value seen.  Common sense tells us that the intermediate integer
+    * representations are no more accurate than +/- 0.5 in the integral values,
+    * the sBIT allows the implementation to be worse than this.  In addition the
+    * PNG specification actually permits any error within the range (-1..+1),
+    * but that is ignored here.  Instead the final digitized value is compared,
+    * below to the digitized value of the error limits - this has the net effect
+    * of allowing (almost) +/-1 in the output value.  It's difficult to see how
+    * any algorithm that digitizes intermediate results can be more accurate.
+    */
+   that->rede += 1./(2*((1U<<that->red_sBIT)-1));
+
+   if (that->colour_type & PNG_COLOR_MASK_COLOR)
+   {
+      that->green = sample_scale(that->greenf, scale);
+      if (sig_bits && that->green_sBIT < that->sample_depth)
+         that->green >>= that->sample_depth - that->green_sBIT;
+
+      that->blue = sample_scale(that->bluef, scale);
+      if (sig_bits && that->blue_sBIT < that->sample_depth)
+         that->blue >>= that->sample_depth - that->blue_sBIT;
+
+      that->greene += 1./(2*((1U<<that->green_sBIT)-1));
+      that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
+   }
+   else
+   {
+      that->blue = that->green = that->red;
+      that->bluef = that->greenf = that->redf;
+      that->bluee = that->greene = that->rede;
+   }
+
+   if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
+      that->colour_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      that->alpha = sample_scale(that->alphaf, scale);
+      that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
+   }
+   else
+   {
+      that->alpha = scale; /* opaque */
+      that->alphaf = 1;    /* Override this. */
+      that->alphae = 0;    /* It's exact ;-) */
+   }
+
+   if (sig_bits && that->alpha_sBIT < that->sample_depth)
+      that->alpha >>= that->sample_depth - that->alpha_sBIT;
+}
+
+/* Static 'end' structure: */
+static image_transform image_transform_end =
+{
+   "(end)", /* name */
+   1, /* enable */
+   0, /* list */
+   0, /* global_use */
+   0, /* local_use */
+   0, /* next */
+   image_transform_ini_end,
+   image_transform_set_end,
+   image_transform_mod_end,
+   0 /* never called, I want it to crash if it is! */
+};
+
+/* Reader callbacks and implementations, where they differ from the standard
+ * ones.
+ */
+static void
+transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
+    const image_transform *transform_list)
+{
+   memset(dp, 0, sizeof *dp);
+
+   /* Standard fields */
+   standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
+      pm->use_update_info);
+
+   /* Parameter fields */
+   dp->pm = pm;
+   dp->transform_list = transform_list;
+   dp->max_gamma_8 = 16;
+
+   /* Local variable fields */
+   dp->output_colour_type = 255; /* invalid */
+   dp->output_bit_depth = 255;  /* invalid */
+   dp->unpacked = 0; /* not unpacked */
+}
+
+static void
+transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
+{
+   /* Reuse the standard stuff as appropriate. */
+   standard_info_part1(&dp->this, pp, pi);
+
+   /* Now set the list of transforms. */
+   dp->transform_list->set(dp->transform_list, dp, pp, pi);
+
+   /* Update the info structure for these transforms: */
+   {
+      int i = dp->this.use_update_info;
+      /* Always do one call, even if use_update_info is 0. */
+      do
+         png_read_update_info(pp, pi);
+      while (--i > 0);
+   }
+
+   /* And get the output information into the standard_display */
+   standard_info_part2(&dp->this, pp, pi, 1/*images*/);
+
+   /* Plus the extra stuff we need for the transform tests: */
+   dp->output_colour_type = png_get_color_type(pp, pi);
+   dp->output_bit_depth = png_get_bit_depth(pp, pi);
+
+   /* If png_set_filler is in action then fake the output color type to include
+    * an alpha channel where appropriate.
+    */
+   if (dp->output_bit_depth >= 8 &&
+       (dp->output_colour_type == PNG_COLOR_TYPE_RGB ||
+        dp->output_colour_type == PNG_COLOR_TYPE_GRAY) && dp->this.filler)
+       dp->output_colour_type |= 4;
+
+   /* Validate the combination of colour type and bit depth that we are getting
+    * out of libpng; the semantics of something not in the PNG spec are, at
+    * best, unclear.
+    */
+   switch (dp->output_colour_type)
+   {
+   case PNG_COLOR_TYPE_PALETTE:
+      if (dp->output_bit_depth > 8) goto error;
+      /* FALLTHROUGH */
+   case PNG_COLOR_TYPE_GRAY:
+      if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
+         dp->output_bit_depth == 4)
+         break;
+      /* FALLTHROUGH */
+   default:
+      if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
+         break;
+      /* FALLTHROUGH */
+   error:
+      {
+         char message[128];
+         size_t pos;
+
+         pos = safecat(message, sizeof message, 0,
+            "invalid final bit depth: colour type(");
+         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
+         pos = safecat(message, sizeof message, pos, ") with bit depth: ");
+         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+
+         png_error(pp, message);
+      }
+   }
+
+   /* Use a test pixel to check that the output agrees with what we expect -
+    * this avoids running the whole test if the output is unexpected.  This also
+    * checks for internal errors.
+    */
+   {
+      image_pixel test_pixel;
+
+      memset(&test_pixel, 0, sizeof test_pixel);
+      test_pixel.colour_type = dp->this.colour_type; /* input */
+      test_pixel.bit_depth = dp->this.bit_depth;
+      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
+         test_pixel.sample_depth = 8;
+      else
+         test_pixel.sample_depth = test_pixel.bit_depth;
+      /* Don't need sBIT here, but it must be set to non-zero to avoid
+       * arithmetic overflows.
+       */
+      test_pixel.have_tRNS = dp->this.is_transparent != 0;
+      test_pixel.red_sBIT = test_pixel.green_sBIT = test_pixel.blue_sBIT =
+         test_pixel.alpha_sBIT = test_pixel.sample_depth;
+
+      dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
+
+      if (test_pixel.colour_type != dp->output_colour_type)
+      {
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0, "colour type ");
+
+         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
+
+         png_error(pp, message);
+      }
+
+      if (test_pixel.bit_depth != dp->output_bit_depth)
+      {
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0, "bit depth ");
+
+         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
+
+         png_error(pp, message);
+      }
+
+      /* If both bit depth and colour type are correct check the sample depth.
+       */
+      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE &&
+          test_pixel.sample_depth != 8) /* oops - internal error! */
+         png_error(pp, "pngvalid: internal: palette sample depth not 8");
+      else if (dp->unpacked && test_pixel.bit_depth != 8)
+         png_error(pp, "pngvalid: internal: bad unpacked pixel depth");
+      else if (!dp->unpacked && test_pixel.colour_type != PNG_COLOR_TYPE_PALETTE
+              && test_pixel.bit_depth != test_pixel.sample_depth)
+      {
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0,
+            "internal: sample depth ");
+
+         /* Because unless something has set 'unpacked' or the image is palette
+          * mapped we expect the transform to keep sample depth and bit depth
+          * the same.
+          */
+         pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
+
+         png_error(pp, message);
+      }
+      else if (test_pixel.bit_depth != dp->output_bit_depth)
+      {
+         /* This could be a libpng error too; libpng has not produced what we
+          * expect for the output bit depth.
+          */
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0,
+            "internal: bit depth ");
+
+         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
+
+         png_error(pp, message);
+      }
+   }
+}
+
+static void PNGCBAPI
+transform_info(png_structp pp, png_infop pi)
+{
+   transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
+      pp, pi);
+}
+
+static void
+transform_range_check(png_const_structp pp, unsigned int r, unsigned int g,
+   unsigned int b, unsigned int a, unsigned int in_digitized, double in,
+   unsigned int out, png_byte sample_depth, double err, double limit,
+   const char *name, double digitization_error)
+{
+   /* Compare the scaled, digitzed, values of our local calculation (in+-err)
+    * with the digitized values libpng produced;  'sample_depth' is the actual
+    * digitization depth of the libpng output colors (the bit depth except for
+    * palette images where it is always 8.)  The check on 'err' is to detect
+    * internal errors in pngvalid itself.
+    */
+   unsigned int max = (1U<<sample_depth)-1;
+   double in_min = ceil((in-err)*max - digitization_error);
+   double in_max = floor((in+err)*max + digitization_error);
+   if (debugonly(err > limit ||) !(out >= in_min && out <= in_max))
+   {
+      char message[256];
+      size_t pos;
+
+      pos = safecat(message, sizeof message, 0, name);
+      pos = safecat(message, sizeof message, pos, " output value error: rgba(");
+      pos = safecatn(message, sizeof message, pos, r);
+      pos = safecat(message, sizeof message, pos, ",");
+      pos = safecatn(message, sizeof message, pos, g);
+      pos = safecat(message, sizeof message, pos, ",");
+      pos = safecatn(message, sizeof message, pos, b);
+      pos = safecat(message, sizeof message, pos, ",");
+      pos = safecatn(message, sizeof message, pos, a);
+      pos = safecat(message, sizeof message, pos, "): ");
+      pos = safecatn(message, sizeof message, pos, out);
+      pos = safecat(message, sizeof message, pos, " expected: ");
+      pos = safecatn(message, sizeof message, pos, in_digitized);
+      pos = safecat(message, sizeof message, pos, " (");
+      pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
+      pos = safecat(message, sizeof message, pos, "..");
+      pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
+      pos = safecat(message, sizeof message, pos, ")");
+
+      png_error(pp, message);
+   }
+
+   UNUSED(limit)
+}
+
+static void
+transform_image_validate(transform_display *dp, png_const_structp pp,
+   png_infop pi)
+{
+   /* Constants for the loop below: */
+   const png_store* const ps = dp->this.ps;
+   png_byte in_ct = dp->this.colour_type;
+   png_byte in_bd = dp->this.bit_depth;
+   png_uint_32 w = dp->this.w;
+   png_uint_32 h = dp->this.h;
+   png_byte out_ct = dp->output_colour_type;
+   png_byte out_bd = dp->output_bit_depth;
+   png_byte sample_depth =
+      (png_byte)(out_ct == PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
+   png_byte red_sBIT = dp->this.red_sBIT;
+   png_byte green_sBIT = dp->this.green_sBIT;
+   png_byte blue_sBIT = dp->this.blue_sBIT;
+   png_byte alpha_sBIT = dp->this.alpha_sBIT;
+   int have_tRNS = dp->this.is_transparent;
+   double digitization_error;
+
+   store_palette out_palette;
+   png_uint_32 y;
+
+   UNUSED(pi)
+
+   /* Check for row overwrite errors */
+   store_image_check(dp->this.ps, pp, 0);
+
+   /* Read the palette corresponding to the output if the output colour type
+    * indicates a palette, otherwise set out_palette to garbage.
+    */
+   if (out_ct == PNG_COLOR_TYPE_PALETTE)
+   {
+      /* Validate that the palette count itself has not changed - this is not
+       * expected.
+       */
+      int npalette = (-1);
+
+      (void)read_palette(out_palette, &npalette, pp, pi);
+      if (npalette != dp->this.npalette)
+         png_error(pp, "unexpected change in palette size");
+
+      digitization_error = .5;
+   }
+   else
+   {
+      png_byte in_sample_depth;
+
+      memset(out_palette, 0x5e, sizeof out_palette);
+
+      /* use-input-precision means assume that if the input has 8 bit (or less)
+       * samples and the output has 16 bit samples the calculations will be done
+       * with 8 bit precision, not 16.
+       */
+      if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
+         in_sample_depth = 8;
+      else
+         in_sample_depth = in_bd;
+
+      if (sample_depth != 16 || in_sample_depth > 8 ||
+         !dp->pm->calculations_use_input_precision)
+         digitization_error = .5;
+
+      /* Else calculations are at 8 bit precision, and the output actually
+       * consists of scaled 8-bit values, so scale .5 in 8 bits to the 16 bits:
+       */
+      else
+         digitization_error = .5 * 257;
+   }
+
+   for (y=0; y<h; ++y)
+   {
+      png_const_bytep const pRow = store_image_row(ps, pp, 0, y);
+      png_uint_32 x;
+
+      /* The original, standard, row pre-transforms. */
+      png_byte std[STANDARD_ROWMAX];
+
+      transform_row(pp, std, in_ct, in_bd, y);
+
+      /* Go through each original pixel transforming it and comparing with what
+       * libpng did to the same pixel.
+       */
+      for (x=0; x<w; ++x)
+      {
+         image_pixel in_pixel, out_pixel;
+         unsigned int r, g, b, a;
+
+         /* Find out what we think the pixel should be: */
+         image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette,
+                 NULL);
+
+         in_pixel.red_sBIT = red_sBIT;
+         in_pixel.green_sBIT = green_sBIT;
+         in_pixel.blue_sBIT = blue_sBIT;
+         in_pixel.alpha_sBIT = alpha_sBIT;
+         in_pixel.have_tRNS = have_tRNS != 0;
+
+         /* For error detection, below. */
+         r = in_pixel.red;
+         g = in_pixel.green;
+         b = in_pixel.blue;
+         a = in_pixel.alpha;
+
+         /* This applies the transforms to the input data, including output
+          * format operations which must be used when reading the output
+          * pixel that libpng produces.
+          */
+         dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
+
+         /* Read the output pixel and compare it to what we got, we don't
+          * use the error field here, so no need to update sBIT.  in_pixel
+          * says whether we expect libpng to change the output format.
+          */
+         image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette,
+                 &in_pixel);
+
+         /* We don't expect changes to the index here even if the bit depth is
+          * changed.
+          */
+         if (in_ct == PNG_COLOR_TYPE_PALETTE &&
+            out_ct == PNG_COLOR_TYPE_PALETTE)
+         {
+            if (in_pixel.palette_index != out_pixel.palette_index)
+               png_error(pp, "unexpected transformed palette index");
+         }
+
+         /* Check the colours for palette images too - in fact the palette could
+          * be separately verified itself in most cases.
+          */
+         if (in_pixel.red != out_pixel.red)
+            transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
+               out_pixel.red, sample_depth, in_pixel.rede,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
+               digitization_error);
+
+         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
+            in_pixel.green != out_pixel.green)
+            transform_range_check(pp, r, g, b, a, in_pixel.green,
+               in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
+               digitization_error);
+
+         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
+            in_pixel.blue != out_pixel.blue)
+            transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
+               out_pixel.blue, sample_depth, in_pixel.bluee,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
+               digitization_error);
+
+         if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
+            in_pixel.alpha != out_pixel.alpha)
+            transform_range_check(pp, r, g, b, a, in_pixel.alpha,
+               in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
+               digitization_error);
+      } /* pixel (x) loop */
+   } /* row (y) loop */
+
+   /* Record that something was actually checked to avoid a false positive. */
+   dp->this.ps->validated = 1;
+}
+
+static void PNGCBAPI
+transform_end(png_structp ppIn, png_infop pi)
+{
+   png_const_structp pp = ppIn;
+   transform_display *dp = voidcast(transform_display*,
+      png_get_progressive_ptr(pp));
+
+   if (!dp->this.speed)
+      transform_image_validate(dp, pp, pi);
+   else
+      dp->this.ps->validated = 1;
+}
+
+/* A single test run. */
+static void
+transform_test(png_modifier *pmIn, png_uint_32 idIn,
+    const image_transform* transform_listIn, const char * const name)
+{
+   transform_display d;
+   context(&pmIn->this, fault);
+
+   transform_display_init(&d, pmIn, idIn, transform_listIn);
+
+   Try
+   {
+      size_t pos = 0;
+      png_structp pp;
+      png_infop pi;
+      char full_name[256];
+
+      /* Make sure the encoding fields are correct and enter the required
+       * modifications.
+       */
+      transform_set_encoding(&d);
+
+      /* Add any modifications required by the transform list. */
+      d.transform_list->ini(d.transform_list, &d);
+
+      /* Add the color space information, if any, to the name. */
+      pos = safecat(full_name, sizeof full_name, pos, name);
+      pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
+
+      /* Get a png_struct for reading the image. */
+      pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
+      standard_palette_init(&d.this);
+
+#     if 0
+         /* Logging (debugging only) */
+         {
+            char buffer[256];
+
+            (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
+               "running test");
+
+            fprintf(stderr, "%s\n", buffer);
+         }
+#     endif
+
+      /* Introduce the correct read function. */
+      if (d.pm->this.progressive)
+      {
+         /* Share the row function with the standard implementation. */
+         png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
+            transform_end);
+
+         /* Now feed data into the reader until we reach the end: */
+         modifier_progressive_read(d.pm, pp, pi);
+      }
+      else
+      {
+         /* modifier_read expects a png_modifier* */
+         png_set_read_fn(pp, d.pm, modifier_read);
+
+         /* Check the header values: */
+         png_read_info(pp, pi);
+
+         /* Process the 'info' requirements. Only one image is generated */
+         transform_info_imp(&d, pp, pi);
+
+         sequential_row(&d.this, pp, pi, -1, 0);
+
+         if (!d.this.speed)
+            transform_image_validate(&d, pp, pi);
+         else
+            d.this.ps->validated = 1;
+      }
+
+      modifier_reset(d.pm);
+   }
+
+   Catch(fault)
+   {
+      modifier_reset(voidcast(png_modifier*,(void*)fault));
+   }
+}
+
+/* The transforms: */
+#define ITSTRUCT(name) image_transform_##name
+#define ITDATA(name) image_transform_data_##name
+#define image_transform_ini image_transform_default_ini
+#define IT(name)\
+static image_transform ITSTRUCT(name) =\
+{\
+   #name,\
+   1, /*enable*/\
+   &PT, /*list*/\
+   0, /*global_use*/\
+   0, /*local_use*/\
+   0, /*next*/\
+   image_transform_ini,\
+   image_transform_png_set_##name##_set,\
+   image_transform_png_set_##name##_mod,\
+   image_transform_png_set_##name##_add\
+}
+#define PT ITSTRUCT(end) /* stores the previous transform */
+
+/* To save code: */
+extern void image_transform_default_ini(const image_transform *this,
+   transform_display *that); /* silence GCC warnings */
+
+void /* private, but almost always needed */
+image_transform_default_ini(const image_transform *this,
+    transform_display *that)
+{
+   this->next->ini(this->next, that);
+}
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+static int
+image_transform_default_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return 1;
+}
+#endif
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_palette_to_rgb */
+static void
+image_transform_png_set_palette_to_rgb_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_palette_to_rgb(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_palette_to_rgb_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_palette_to_rgb_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return colour_type == PNG_COLOR_TYPE_PALETTE;
+}
+
+IT(palette_to_rgb);
+#undef PT
+#define PT ITSTRUCT(palette_to_rgb)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_tRNS_to_alpha */
+static void
+image_transform_png_set_tRNS_to_alpha_set(const image_transform *this,
+   transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_tRNS_to_alpha(pp);
+
+   /* If there was a tRNS chunk that would get expanded and add an alpha
+    * channel is_transparent must be updated:
+    */
+   if (that->this.has_tRNS)
+      that->this.is_transparent = 1;
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_tRNS_to_alpha_mod(const image_transform *this,
+   image_pixel *that, png_const_structp pp,
+   const transform_display *display)
+{
+#if PNG_LIBPNG_VER < 10700
+   /* LIBPNG BUG: this always forces palette images to RGB. */
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+#endif
+
+   /* This effectively does an 'expand' only if there is some transparency to
+    * convert to an alpha channel.
+    */
+   if (that->have_tRNS)
+#     if PNG_LIBPNG_VER >= 10700
+         if (that->colour_type != PNG_COLOR_TYPE_PALETTE &&
+             (that->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
+#     endif
+      image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
+
+#if PNG_LIBPNG_VER < 10700
+   /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
+   else
+   {
+      if (that->bit_depth < 8)
+         that->bit_depth =8;
+      if (that->sample_depth < 8)
+         that->sample_depth = 8;
+   }
+#endif
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* We don't know yet whether there will be a tRNS chunk, but we know that
+    * this transformation should do nothing if there already is an alpha
+    * channel.  In addition, after the bug fix in 1.7.0, there is no longer
+    * any action on a palette image.
+    */
+   return
+#  if PNG_LIBPNG_VER >= 10700
+      colour_type != PNG_COLOR_TYPE_PALETTE &&
+#  endif
+   (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
+}
+
+IT(tRNS_to_alpha);
+#undef PT
+#define PT ITSTRUCT(tRNS_to_alpha)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* png_set_gray_to_rgb */
+static void
+image_transform_png_set_gray_to_rgb_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_gray_to_rgb(pp);
+   /* NOTE: this doesn't result in tRNS expansion. */
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_gray_to_rgb_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* NOTE: we can actually pend the tRNS processing at this point because we
+    * can correctly recognize the original pixel value even though we have
+    * mapped the one gray channel to the three RGB ones, but in fact libpng
+    * doesn't do this, so we don't either.
+    */
+   if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
+
+   /* Simply expand the bit depth and alter the colour type as required. */
+   if (that->colour_type == PNG_COLOR_TYPE_GRAY)
+   {
+      /* RGB images have a bit depth at least equal to '8' */
+      if (that->bit_depth < 8)
+         that->sample_depth = that->bit_depth = 8;
+
+      /* And just changing the colour type works here because the green and blue
+       * channels are being maintained in lock-step with the red/gray:
+       */
+      that->colour_type = PNG_COLOR_TYPE_RGB;
+   }
+
+   else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_gray_to_rgb_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
+}
+
+IT(gray_to_rgb);
+#undef PT
+#define PT ITSTRUCT(gray_to_rgb)
+#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_expand */
+static void
+image_transform_png_set_expand_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_expand(pp);
+
+   if (that->this.has_tRNS)
+      that->this.is_transparent = 1;
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* The general expand case depends on what the colour type is: */
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+   else if (that->bit_depth < 8) /* grayscale */
+      that->sample_depth = that->bit_depth = 8;
+
+   if (that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_expand_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
+    * depth is at least 8 already.
+    */
+   return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
+}
+
+IT(expand);
+#undef PT
+#define PT ITSTRUCT(expand)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_expand_gray_1_2_4_to_8
+ * Pre 1.7.0 LIBPNG BUG: this just does an 'expand'
+ */
+static void
+image_transform_png_set_expand_gray_1_2_4_to_8_set(
+    const image_transform *this, transform_display *that, png_structp pp,
+    png_infop pi)
+{
+   png_set_expand_gray_1_2_4_to_8(pp);
+   /* NOTE: don't expect this to expand tRNS */
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_gray_1_2_4_to_8_mod(
+    const image_transform *this, image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+#if PNG_LIBPNG_VER < 10700
+   image_transform_png_set_expand_mod(this, that, pp, display);
+#else
+   /* Only expand grayscale of bit depth less than 8: */
+   if (that->colour_type == PNG_COLOR_TYPE_GRAY &&
+       that->bit_depth < 8)
+      that->sample_depth = that->bit_depth = 8;
+
+   this->next->mod(this->next, that, pp, display);
+#endif /* 1.7 or later */
+}
+
+static int
+image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+#if PNG_LIBPNG_VER < 10700
+   return image_transform_png_set_expand_add(this, that, colour_type,
+      bit_depth);
+#else
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* This should do nothing unless the color type is gray and the bit depth is
+    * less than 8:
+    */
+   return colour_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8;
+#endif /* 1.7 or later */
+}
+
+IT(expand_gray_1_2_4_to_8);
+#undef PT
+#define PT ITSTRUCT(expand_gray_1_2_4_to_8)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* png_set_expand_16 */
+static void
+image_transform_png_set_expand_16_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_expand_16(pp);
+
+   /* NOTE: prior to 1.7 libpng does SET_EXPAND as well, so tRNS is expanded. */
+#  if PNG_LIBPNG_VER < 10700
+      if (that->this.has_tRNS)
+         that->this.is_transparent = 1;
+#  endif
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_16_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* Expect expand_16 to expand everything to 16 bits as a result of also
+    * causing 'expand' to happen.
+    */
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+
+   if (that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
+
+   if (that->bit_depth < 16)
+      that->sample_depth = that->bit_depth = 16;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_expand_16_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   /* expand_16 does something unless the bit depth is already 16. */
+   return bit_depth < 16;
+}
+
+IT(expand_16);
+#undef PT
+#define PT ITSTRUCT(expand_16)
+#endif /* PNG_READ_EXPAND_16_SUPPORTED */
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED  /* API added in 1.5.4 */
+/* png_set_scale_16 */
+static void
+image_transform_png_set_scale_16_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_scale_16(pp);
+#  if PNG_LIBPNG_VER < 10700
+      /* libpng will limit the gamma table size: */
+      that->max_gamma_8 = PNG_MAX_GAMMA_8;
+#  endif
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_scale_16_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth == 16)
+   {
+      that->sample_depth = that->bit_depth = 8;
+      if (that->red_sBIT > 8) that->red_sBIT = 8;
+      if (that->green_sBIT > 8) that->green_sBIT = 8;
+      if (that->blue_sBIT > 8) that->blue_sBIT = 8;
+      if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_scale_16_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   return bit_depth > 8;
+}
+
+IT(scale_16);
+#undef PT
+#define PT ITSTRUCT(scale_16)
+#endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
+
+#ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
+/* png_set_strip_16 */
+static void
+image_transform_png_set_strip_16_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_strip_16(pp);
+#  if PNG_LIBPNG_VER < 10700
+      /* libpng will limit the gamma table size: */
+      that->max_gamma_8 = PNG_MAX_GAMMA_8;
+#  endif
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_strip_16_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth == 16)
+   {
+      that->sample_depth = that->bit_depth = 8;
+      if (that->red_sBIT > 8) that->red_sBIT = 8;
+      if (that->green_sBIT > 8) that->green_sBIT = 8;
+      if (that->blue_sBIT > 8) that->blue_sBIT = 8;
+      if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
+
+      /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
+       * configuration option is set.  From 1.5.4 the flag is never set and the
+       * 'scale' API (above) must be used.
+       */
+#     ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
+#        if PNG_LIBPNG_VER >= 10504
+#           error PNG_READ_ACCURATE_SCALE should not be set
+#        endif
+
+         /* The strip 16 algorithm drops the low 8 bits rather than calculating
+          * 1/257, so we need to adjust the permitted errors appropriately:
+          * Notice that this is only relevant prior to the addition of the
+          * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
+          */
+         {
+            const double d = (255-128.5)/65535;
+            that->rede += d;
+            that->greene += d;
+            that->bluee += d;
+            that->alphae += d;
+         }
+#     endif
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_strip_16_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   return bit_depth > 8;
+}
+
+IT(strip_16);
+#undef PT
+#define PT ITSTRUCT(strip_16)
+#endif /* PNG_READ_16_TO_8_SUPPORTED */
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+/* png_set_strip_alpha */
+static void
+image_transform_png_set_strip_alpha_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_strip_alpha(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_strip_alpha_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_GRAY;
+   else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_RGB;
+
+   that->have_tRNS = 0;
+   that->alphaf = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_strip_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
+}
+
+IT(strip_alpha);
+#undef PT
+#define PT ITSTRUCT(strip_alpha)
+#endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
+ * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
+ *    png_fixed_point green)
+ * png_get_rgb_to_gray_status
+ *
+ * The 'default' test here uses values known to be used inside libpng prior to
+ * 1.7.0:
+ *
+ *   red:    6968
+ *   green: 23434
+ *   blue:   2366
+ *
+ * These values are being retained for compatibility, along with the somewhat
+ * broken truncation calculation in the fast-and-inaccurate code path.  Older
+ * versions of libpng will fail the accuracy tests below because they use the
+ * truncation algorithm everywhere.
+ */
+#define data ITDATA(rgb_to_gray)
+static struct
+{
+   double gamma;      /* File gamma to use in processing */
+
+   /* The following are the parameters for png_set_rgb_to_gray: */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+      double red_to_set;
+      double green_to_set;
+#  else
+      png_fixed_point red_to_set;
+      png_fixed_point green_to_set;
+#  endif
+
+   /* The actual coefficients: */
+   double red_coefficient;
+   double green_coefficient;
+   double blue_coefficient;
+
+   /* Set if the coeefficients have been overridden. */
+   int coefficients_overridden;
+} data;
+
+#undef image_transform_ini
+#define image_transform_ini image_transform_png_set_rgb_to_gray_ini
+static void
+image_transform_png_set_rgb_to_gray_ini(const image_transform *this,
+    transform_display *that)
+{
+   png_modifier *pm = that->pm;
+   const color_encoding *e = pm->current_encoding;
+
+   UNUSED(this)
+
+   /* Since we check the encoding this flag must be set: */
+   pm->test_uses_encoding = 1;
+
+   /* If 'e' is not NULL chromaticity information is present and either a cHRM
+    * or an sRGB chunk will be inserted.
+    */
+   if (e != 0)
+   {
+      /* Coefficients come from the encoding, but may need to be normalized to a
+       * white point Y of 1.0
+       */
+      const double whiteY = e->red.Y + e->green.Y + e->blue.Y;
+
+      data.red_coefficient = e->red.Y;
+      data.green_coefficient = e->green.Y;
+      data.blue_coefficient = e->blue.Y;
+
+      if (whiteY != 1)
+      {
+         data.red_coefficient /= whiteY;
+         data.green_coefficient /= whiteY;
+         data.blue_coefficient /= whiteY;
+      }
+   }
+
+   else
+   {
+      /* The default (built in) coeffcients, as above: */
+#     if PNG_LIBPNG_VER < 10700
+         data.red_coefficient = 6968 / 32768.;
+         data.green_coefficient = 23434 / 32768.;
+         data.blue_coefficient = 2366 / 32768.;
+#     else
+         data.red_coefficient = .2126;
+         data.green_coefficient = .7152;
+         data.blue_coefficient = .0722;
+#     endif
+   }
+
+   data.gamma = pm->current_gamma;
+
+   /* If not set then the calculations assume linear encoding (implicitly): */
+   if (data.gamma == 0)
+      data.gamma = 1;
+
+   /* The arguments to png_set_rgb_to_gray can override the coefficients implied
+    * by the color space encoding.  If doing exhaustive checks do the override
+    * in each case, otherwise do it randomly.
+    */
+   if (pm->test_exhaustive)
+   {
+      /* First time in coefficients_overridden is 0, the following sets it to 1,
+       * so repeat if it is set.  If a test fails this may mean we subsequently
+       * skip a non-override test, ignore that.
+       */
+      data.coefficients_overridden = !data.coefficients_overridden;
+      pm->repeat = data.coefficients_overridden != 0;
+   }
+
+   else
+      data.coefficients_overridden = random_choice();
+
+   if (data.coefficients_overridden)
+   {
+      /* These values override the color encoding defaults, simply use random
+       * numbers.
+       */
+      png_uint_32 ru;
+      double total;
+
+      ru = random_u32();
+      data.green_coefficient = total = (ru & 0xffff) / 65535.;
+      ru >>= 16;
+      data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
+      total += data.red_coefficient;
+      data.blue_coefficient = 1 - total;
+
+#     ifdef PNG_FLOATING_POINT_SUPPORTED
+         data.red_to_set = data.red_coefficient;
+         data.green_to_set = data.green_coefficient;
+#     else
+         data.red_to_set = fix(data.red_coefficient);
+         data.green_to_set = fix(data.green_coefficient);
+#     endif
+
+      /* The following just changes the error messages: */
+      pm->encoding_ignored = 1;
+   }
+
+   else
+   {
+      data.red_to_set = -1;
+      data.green_to_set = -1;
+   }
+
+   /* Adjust the error limit in the png_modifier because of the larger errors
+    * produced in the digitization during the gamma handling.
+    */
+   if (data.gamma != 1) /* Use gamma tables */
+   {
+      if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
+      {
+         /* The computations have the form:
+          *
+          *    r * rc + g * gc + b * bc
+          *
+          *  Each component of which is +/-1/65535 from the gamma_to_1 table
+          *  lookup, resulting in a base error of +/-6.  The gamma_from_1
+          *  conversion adds another +/-2 in the 16-bit case and
+          *  +/-(1<<(15-PNG_MAX_GAMMA_8)) in the 8-bit case.
+          */
+#        if PNG_LIBPNG_VER < 10700
+            if (that->this.bit_depth < 16)
+               that->max_gamma_8 = PNG_MAX_GAMMA_8;
+#        endif
+         that->pm->limit += pow(
+            (that->this.bit_depth == 16 || that->max_gamma_8 > 14 ?
+               8. :
+               6. + (1<<(15-that->max_gamma_8))
+            )/65535, data.gamma);
+      }
+
+      else
+      {
+         /* Rounding to 8 bits in the linear space causes massive errors which
+          * will trigger the error check in transform_range_check.  Fix that
+          * here by taking the gamma encoding into account.
+          *
+          * When DIGITIZE is set because a pre-1.7 version of libpng is being
+          * tested allow a bigger slack.
+          *
+          * NOTE: this number only affects the internal limit check in pngvalid,
+          * it has no effect on the limits applied to the libpng values.
+          */
+#if DIGITIZE
+          that->pm->limit += pow( 2.0/255, data.gamma);
+#else
+          that->pm->limit += pow( 1.0/255, data.gamma);
+#endif
+      }
+   }
+
+   else
+   {
+      /* With no gamma correction a large error comes from the truncation of the
+       * calculation in the 8 bit case, allow for that here.
+       */
+      if (that->this.bit_depth != 16 && !pm->assume_16_bit_calculations)
+         that->pm->limit += 4E-3;
+   }
+}
+
+static void
+image_transform_png_set_rgb_to_gray_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   int error_action = 1; /* no error, no defines in png.h */
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+      png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
+#  else
+      png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
+         data.green_to_set);
+#  endif
+
+#  ifdef PNG_READ_cHRM_SUPPORTED
+      if (that->pm->current_encoding != 0)
+      {
+         /* We have an encoding so a cHRM chunk may have been set; if so then
+          * check that the libpng APIs give the correct (X,Y,Z) values within
+          * some margin of error for the round trip through the chromaticity
+          * form.
+          */
+#        ifdef PNG_FLOATING_POINT_SUPPORTED
+#           define API_function png_get_cHRM_XYZ
+#           define API_form "FP"
+#           define API_type double
+#           define API_cvt(x) (x)
+#        else
+#           define API_function png_get_cHRM_XYZ_fixed
+#           define API_form "fixed"
+#           define API_type png_fixed_point
+#           define API_cvt(x) ((double)(x)/PNG_FP_1)
+#        endif
+
+         API_type rX, gX, bX;
+         API_type rY, gY, bY;
+         API_type rZ, gZ, bZ;
+
+         if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
+               & PNG_INFO_cHRM) != 0)
+         {
+            double maxe;
+            const char *el;
+            color_encoding e, o;
+
+            /* Expect libpng to return a normalized result, but the original
+             * color space encoding may not be normalized.
+             */
+            modifier_current_encoding(that->pm, &o);
+            normalize_color_encoding(&o);
+
+            /* Sanity check the pngvalid code - the coefficients should match
+             * the normalized Y values of the encoding unless they were
+             * overridden.
+             */
+            if (data.red_to_set == -1 && data.green_to_set == -1 &&
+               (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
+               fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
+               fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
+               png_error(pp, "internal pngvalid cHRM coefficient error");
+
+            /* Generate a colour space encoding. */
+            e.gamma = o.gamma; /* not used */
+            e.red.X = API_cvt(rX);
+            e.red.Y = API_cvt(rY);
+            e.red.Z = API_cvt(rZ);
+            e.green.X = API_cvt(gX);
+            e.green.Y = API_cvt(gY);
+            e.green.Z = API_cvt(gZ);
+            e.blue.X = API_cvt(bX);
+            e.blue.Y = API_cvt(bY);
+            e.blue.Z = API_cvt(bZ);
+
+            /* This should match the original one from the png_modifier, within
+             * the range permitted by the libpng fixed point representation.
+             */
+            maxe = 0;
+            el = "-"; /* Set to element name with error */
+
+#           define CHECK(col,x)\
+            {\
+               double err = fabs(o.col.x - e.col.x);\
+               if (err > maxe)\
+               {\
+                  maxe = err;\
+                  el = #col "(" #x ")";\
+               }\
+            }
+
+            CHECK(red,X)
+            CHECK(red,Y)
+            CHECK(red,Z)
+            CHECK(green,X)
+            CHECK(green,Y)
+            CHECK(green,Z)
+            CHECK(blue,X)
+            CHECK(blue,Y)
+            CHECK(blue,Z)
+
+            /* Here in both fixed and floating cases to check the values read
+             * from the cHRm chunk.  PNG uses fixed point in the cHRM chunk, so
+             * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
+             */
+            if (maxe >= 1E-5)
+            {
+               size_t pos = 0;
+               char buffer[256];
+
+               pos = safecat(buffer, sizeof buffer, pos, API_form);
+               pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
+               pos = safecat(buffer, sizeof buffer, pos, el);
+               pos = safecat(buffer, sizeof buffer, pos, " error: ");
+               pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
+               pos = safecat(buffer, sizeof buffer, pos, " ");
+               /* Print the color space without the gamma value: */
+               pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
+               pos = safecat(buffer, sizeof buffer, pos, " -> ");
+               pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
+
+               png_error(pp, buffer);
+            }
+         }
+      }
+#  endif /* READ_cHRM */
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_rgb_to_gray_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      double gray, err;
+
+#     if PNG_LIBPNG_VER < 10700
+         if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+            image_pixel_convert_PLTE(that);
+#     endif
+
+      /* Image now has RGB channels... */
+#  if DIGITIZE
+      {
+         png_modifier *pm = display->pm;
+         unsigned int sample_depth = that->sample_depth;
+         unsigned int calc_depth = (pm->assume_16_bit_calculations ? 16 :
+            sample_depth);
+         unsigned int gamma_depth =
+            (sample_depth == 16 ?
+               display->max_gamma_8 :
+               (pm->assume_16_bit_calculations ?
+                  display->max_gamma_8 :
+                  sample_depth));
+         int isgray;
+         double r, g, b;
+         double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
+
+         /* Do this using interval arithmetic, otherwise it is too difficult to
+          * handle the errors correctly.
+          *
+          * To handle the gamma correction work out the upper and lower bounds
+          * of the digitized value.  Assume rounding here - normally the values
+          * will be identical after this operation if there is only one
+          * transform, feel free to delete the png_error checks on this below in
+          * the future (this is just me trying to ensure it works!)
+          *
+          * Interval arithmetic is exact, but to implement it it must be
+          * possible to control the floating point implementation rounding mode.
+          * This cannot be done in ANSI-C, so instead I reduce the 'lo' values
+          * by DBL_EPSILON and increase the 'hi' values by the same.
+          */
+#        define DD(v,d,r) (digitize(v*(1-DBL_EPSILON), d, r) * (1-DBL_EPSILON))
+#        define DU(v,d,r) (digitize(v*(1+DBL_EPSILON), d, r) * (1+DBL_EPSILON))
+
+         r = rlo = rhi = that->redf;
+         rlo -= that->rede;
+         rlo = DD(rlo, calc_depth, 1/*round*/);
+         rhi += that->rede;
+         rhi = DU(rhi, calc_depth, 1/*round*/);
+
+         g = glo = ghi = that->greenf;
+         glo -= that->greene;
+         glo = DD(glo, calc_depth, 1/*round*/);
+         ghi += that->greene;
+         ghi = DU(ghi, calc_depth, 1/*round*/);
+
+         b = blo = bhi = that->bluef;
+         blo -= that->bluee;
+         blo = DD(blo, calc_depth, 1/*round*/);
+         bhi += that->bluee;
+         bhi = DU(bhi, calc_depth, 1/*round*/);
+
+         isgray = r==g && g==b;
+
+         if (data.gamma != 1)
+         {
+            const double power = 1/data.gamma;
+            const double abse = .5/(sample_depth == 16 ? 65535 : 255);
+
+            /* If a gamma calculation is done it is done using lookup tables of
+             * precision gamma_depth, so the already digitized value above may
+             * need to be further digitized here.
+             */
+            if (gamma_depth != calc_depth)
+            {
+               rlo = DD(rlo, gamma_depth, 0/*truncate*/);
+               rhi = DU(rhi, gamma_depth, 0/*truncate*/);
+               glo = DD(glo, gamma_depth, 0/*truncate*/);
+               ghi = DU(ghi, gamma_depth, 0/*truncate*/);
+               blo = DD(blo, gamma_depth, 0/*truncate*/);
+               bhi = DU(bhi, gamma_depth, 0/*truncate*/);
+            }
+
+            /* 'abse' is the error in the gamma table calculation itself. */
+            r = pow(r, power);
+            rlo = DD(pow(rlo, power)-abse, calc_depth, 1);
+            rhi = DU(pow(rhi, power)+abse, calc_depth, 1);
+
+            g = pow(g, power);
+            glo = DD(pow(glo, power)-abse, calc_depth, 1);
+            ghi = DU(pow(ghi, power)+abse, calc_depth, 1);
+
+            b = pow(b, power);
+            blo = DD(pow(blo, power)-abse, calc_depth, 1);
+            bhi = DU(pow(bhi, power)+abse, calc_depth, 1);
+         }
+
+         /* Now calculate the actual gray values.  Although the error in the
+          * coefficients depends on whether they were specified on the command
+          * line (in which case truncation to 15 bits happened) or not (rounding
+          * was used) the maximum error in an individual coefficient is always
+          * 2/32768, because even in the rounding case the requirement that
+          * coefficients add up to 32768 can cause a larger rounding error.
+          *
+          * The only time when rounding doesn't occur in 1.5.5 and later is when
+          * the non-gamma code path is used for less than 16 bit data.
+          */
+         gray = r * data.red_coefficient + g * data.green_coefficient +
+            b * data.blue_coefficient;
+
+         {
+            int do_round = data.gamma != 1 || calc_depth == 16;
+            const double ce = 2. / 32768;
+
+            graylo = DD(rlo * (data.red_coefficient-ce) +
+               glo * (data.green_coefficient-ce) +
+               blo * (data.blue_coefficient-ce), calc_depth, do_round);
+            if (graylo > gray) /* always accept the right answer */
+               graylo = gray;
+
+            grayhi = DU(rhi * (data.red_coefficient+ce) +
+               ghi * (data.green_coefficient+ce) +
+               bhi * (data.blue_coefficient+ce), calc_depth, do_round);
+            if (grayhi < gray)
+               grayhi = gray;
+         }
+
+         /* And invert the gamma. */
+         if (data.gamma != 1)
+         {
+            const double power = data.gamma;
+
+            /* And this happens yet again, shifting the values once more. */
+            if (gamma_depth != sample_depth)
+            {
+               rlo = DD(rlo, gamma_depth, 0/*truncate*/);
+               rhi = DU(rhi, gamma_depth, 0/*truncate*/);
+               glo = DD(glo, gamma_depth, 0/*truncate*/);
+               ghi = DU(ghi, gamma_depth, 0/*truncate*/);
+               blo = DD(blo, gamma_depth, 0/*truncate*/);
+               bhi = DU(bhi, gamma_depth, 0/*truncate*/);
+            }
+
+            gray = pow(gray, power);
+            graylo = DD(pow(graylo, power), sample_depth, 1);
+            grayhi = DU(pow(grayhi, power), sample_depth, 1);
+         }
+
+#        undef DD
+#        undef DU
+
+         /* Now the error can be calculated.
+          *
+          * If r==g==b because there is no overall gamma correction libpng
+          * currently preserves the original value.
+          */
+         if (isgray)
+            err = (that->rede + that->greene + that->bluee)/3;
+
+         else
+         {
+            err = fabs(grayhi-gray);
+
+            if (fabs(gray - graylo) > err)
+               err = fabs(graylo-gray);
+
+#if !RELEASE_BUILD
+            /* Check that this worked: */
+            if (err > pm->limit)
+            {
+               size_t pos = 0;
+               char buffer[128];
+
+               pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
+               pos = safecatd(buffer, sizeof buffer, pos, err, 6);
+               pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
+               pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
+               png_warning(pp, buffer);
+               pm->limit = err;
+            }
+#endif /* !RELEASE_BUILD */
+         }
+      }
+#  else  /* !DIGITIZE */
+      {
+         double r = that->redf;
+         double re = that->rede;
+         double g = that->greenf;
+         double ge = that->greene;
+         double b = that->bluef;
+         double be = that->bluee;
+
+#        if PNG_LIBPNG_VER < 10700
+            /* The true gray case involves no math in earlier versions (not
+             * true, there was some if gamma correction was happening too.)
+             */
+            if (r == g && r == b)
+            {
+               gray = r;
+               err = re;
+               if (err < ge) err = ge;
+               if (err < be) err = be;
+            }
+
+            else
+#        endif /* before 1.7 */
+         if (data.gamma == 1)
+         {
+            /* There is no need to do the conversions to and from linear space,
+             * so the calculation should be a lot more accurate.  There is a
+             * built in error in the coefficients because they only have 15 bits
+             * and are adjusted to make sure they add up to 32768.  This
+             * involves a integer calculation with truncation of the form:
+             *
+             *     ((int)(coefficient * 100000) * 32768)/100000
+             *
+             * This is done to the red and green coefficients (the ones
+             * provided to the API) then blue is calculated from them so the
+             * result adds up to 32768.  In the worst case this can result in
+             * a -1 error in red and green and a +2 error in blue.  Consequently
+             * the worst case in the calculation below is 2/32768 error.
+             *
+             * TODO: consider fixing this in libpng by rounding the calculation
+             * limiting the error to 1/32768.
+             *
+             * Handling this by adding 2/32768 here avoids needing to increase
+             * the global error limits to take this into account.)
+             */
+            gray = r * data.red_coefficient + g * data.green_coefficient +
+               b * data.blue_coefficient;
+            err = re * data.red_coefficient + ge * data.green_coefficient +
+               be * data.blue_coefficient + 2./32768 + gray * 5 * DBL_EPSILON;
+         }
+
+         else
+         {
+            /* The calculation happens in linear space, and this produces much
+             * wider errors in the encoded space.  These are handled here by
+             * factoring the errors in to the calculation.  There are two table
+             * lookups in the calculation and each introduces a quantization
+             * error defined by the table size.
+             */
+            png_modifier *pm = display->pm;
+            double in_qe = (that->sample_depth > 8 ? .5/65535 : .5/255);
+            double out_qe = (that->sample_depth > 8 ? .5/65535 :
+               (pm->assume_16_bit_calculations ? .5/(1<<display->max_gamma_8) :
+               .5/255));
+            double rhi, ghi, bhi, grayhi;
+            double g1 = 1/data.gamma;
+
+            rhi = r + re + in_qe; if (rhi > 1) rhi = 1;
+            r -= re + in_qe; if (r < 0) r = 0;
+            ghi = g + ge + in_qe; if (ghi > 1) ghi = 1;
+            g -= ge + in_qe; if (g < 0) g = 0;
+            bhi = b + be + in_qe; if (bhi > 1) bhi = 1;
+            b -= be + in_qe; if (b < 0) b = 0;
+
+            r = pow(r, g1)*(1-DBL_EPSILON); rhi = pow(rhi, g1)*(1+DBL_EPSILON);
+            g = pow(g, g1)*(1-DBL_EPSILON); ghi = pow(ghi, g1)*(1+DBL_EPSILON);
+            b = pow(b, g1)*(1-DBL_EPSILON); bhi = pow(bhi, g1)*(1+DBL_EPSILON);
+
+            /* Work out the lower and upper bounds for the gray value in the
+             * encoded space, then work out an average and error.  Remove the
+             * previously added input quantization error at this point.
+             */
+            gray = r * data.red_coefficient + g * data.green_coefficient +
+               b * data.blue_coefficient - 2./32768 - out_qe;
+            if (gray <= 0)
+               gray = 0;
+            else
+            {
+               gray *= (1 - 6 * DBL_EPSILON);
+               gray = pow(gray, data.gamma) * (1-DBL_EPSILON);
+            }
+
+            grayhi = rhi * data.red_coefficient + ghi * data.green_coefficient +
+               bhi * data.blue_coefficient + 2./32768 + out_qe;
+            grayhi *= (1 + 6 * DBL_EPSILON);
+            if (grayhi >= 1)
+               grayhi = 1;
+            else
+               grayhi = pow(grayhi, data.gamma) * (1+DBL_EPSILON);
+
+            err = (grayhi - gray) / 2;
+            gray = (grayhi + gray) / 2;
+
+            if (err <= in_qe)
+               err = gray * DBL_EPSILON;
+
+            else
+               err -= in_qe;
+
+#if !RELEASE_BUILD
+            /* Validate that the error is within limits (this has caused
+             * problems before, it's much easier to detect them here.)
+             */
+            if (err > pm->limit)
+            {
+               size_t pos = 0;
+               char buffer[128];
+
+               pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
+               pos = safecatd(buffer, sizeof buffer, pos, err, 6);
+               pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
+               pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
+               png_warning(pp, buffer);
+               pm->limit = err;
+            }
+#endif /* !RELEASE_BUILD */
+         }
+      }
+#  endif /* !DIGITIZE */
+
+      that->bluef = that->greenf = that->redf = gray;
+      that->bluee = that->greene = that->rede = err;
+
+      /* The sBIT is the minimum of the three colour channel sBITs. */
+      if (that->red_sBIT > that->green_sBIT)
+         that->red_sBIT = that->green_sBIT;
+      if (that->red_sBIT > that->blue_sBIT)
+         that->red_sBIT = that->blue_sBIT;
+      that->blue_sBIT = that->green_sBIT = that->red_sBIT;
+
+      /* And remove the colour bit in the type: */
+      if (that->colour_type == PNG_COLOR_TYPE_RGB)
+         that->colour_type = PNG_COLOR_TYPE_GRAY;
+      else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_rgb_to_gray_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
+}
+
+#undef data
+IT(rgb_to_gray);
+#undef PT
+#define PT ITSTRUCT(rgb_to_gray)
+#undef image_transform_ini
+#define image_transform_ini image_transform_default_ini
+#endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* png_set_background(png_structp, png_const_color_16p background_color,
+ *    int background_gamma_code, int need_expand, double background_gamma)
+ * png_set_background_fixed(png_structp, png_const_color_16p background_color,
+ *    int background_gamma_code, int need_expand,
+ *    png_fixed_point background_gamma)
+ *
+ * This ignores the gamma (at present.)
+*/
+#define data ITDATA(background)
+static image_pixel data;
+
+static void
+image_transform_png_set_background_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_byte colour_type, bit_depth;
+   png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
+   int expand;
+   png_color_16 back;
+
+   /* We need a background colour, because we don't know exactly what transforms
+    * have been set we have to supply the colour in the original file format and
+    * so we need to know what that is!  The background colour is stored in the
+    * transform_display.
+    */
+   R8(random_bytes);
+
+   /* Read the random value, for colour type 3 the background colour is actually
+    * expressed as a 24bit rgb, not an index.
+    */
+   colour_type = that->this.colour_type;
+   if (colour_type == 3)
+   {
+      colour_type = PNG_COLOR_TYPE_RGB;
+      bit_depth = 8;
+      expand = 0; /* passing in an RGB not a pixel index */
+   }
+
+   else
+   {
+      if (that->this.has_tRNS)
+         that->this.is_transparent = 1;
+
+      bit_depth = that->this.bit_depth;
+      expand = 1;
+   }
+
+   image_pixel_init(&data, random_bytes, colour_type,
+      bit_depth, 0/*x*/, 0/*unused: palette*/, NULL/*format*/);
+
+   /* Extract the background colour from this image_pixel, but make sure the
+    * unused fields of 'back' are garbage.
+    */
+   R8(back);
+
+   if (colour_type & PNG_COLOR_MASK_COLOR)
+   {
+      back.red = (png_uint_16)data.red;
+      back.green = (png_uint_16)data.green;
+      back.blue = (png_uint_16)data.blue;
+   }
+
+   else
+      back.gray = (png_uint_16)data.red;
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
+#else
+   png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
+#endif
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_background_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* Check for tRNS first: */
+   if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
+      image_pixel_add_alpha(that, &display->this, 1/*for background*/);
+
+   /* This is only necessary if the alpha value is less than 1. */
+   if (that->alphaf < 1)
+   {
+      /* Now we do the background calculation without any gamma correction. */
+      if (that->alphaf <= 0)
+      {
+         that->redf = data.redf;
+         that->greenf = data.greenf;
+         that->bluef = data.bluef;
+
+         that->rede = data.rede;
+         that->greene = data.greene;
+         that->bluee = data.bluee;
+
+         that->red_sBIT= data.red_sBIT;
+         that->green_sBIT= data.green_sBIT;
+         that->blue_sBIT= data.blue_sBIT;
+      }
+
+      else /* 0 < alpha < 1 */
+      {
+         double alf = 1 - that->alphaf;
+
+         that->redf = that->redf * that->alphaf + data.redf * alf;
+         that->rede = that->rede * that->alphaf + data.rede * alf +
+            DBL_EPSILON;
+         that->greenf = that->greenf * that->alphaf + data.greenf * alf;
+         that->greene = that->greene * that->alphaf + data.greene * alf +
+            DBL_EPSILON;
+         that->bluef = that->bluef * that->alphaf + data.bluef * alf;
+         that->bluee = that->bluee * that->alphaf + data.bluee * alf +
+            DBL_EPSILON;
+      }
+
+      /* Remove the alpha type and set the alpha (not in that order.) */
+      that->alphaf = 1;
+      that->alphae = 0;
+   }
+
+   if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_RGB;
+   else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_GRAY;
+   /* PNG_COLOR_TYPE_PALETTE is not changed */
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+#define image_transform_png_set_background_add image_transform_default_add
+
+#undef data
+IT(background);
+#undef PT
+#define PT ITSTRUCT(background)
+#endif /* PNG_READ_BACKGROUND_SUPPORTED */
+
+/* png_set_quantize(png_structp, png_colorp palette, int num_palette,
+ *    int maximum_colors, png_const_uint_16p histogram, int full_quantize)
+ *
+ * Very difficult to validate this!
+ */
+/*NOTE: TBD NYI */
+
+/* The data layout transforms are handled by swapping our own channel data,
+ * necessarily these need to happen at the end of the transform list because the
+ * semantic of the channels changes after these are executed.  Some of these,
+ * like set_shift and set_packing, can't be done at present because they change
+ * the layout of the data at the sub-sample level so sample() won't get the
+ * right answer.
+ */
+/* png_set_invert_alpha */
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+/* Invert the alpha channel
+ *
+ *  png_set_invert_alpha(png_structrp png_ptr)
+ */
+static void
+image_transform_png_set_invert_alpha_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_invert_alpha(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_invert_alpha_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type & 4)
+      that->alpha_inverted = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_invert_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* Only has an effect on pixels with alpha: */
+   return (colour_type & 4) != 0;
+}
+
+IT(invert_alpha);
+#undef PT
+#define PT ITSTRUCT(invert_alpha)
+
+#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
+
+/* png_set_bgr */
+#ifdef PNG_READ_BGR_SUPPORTED
+/* Swap R,G,B channels to order B,G,R.
+ *
+ *  png_set_bgr(png_structrp png_ptr)
+ *
+ * This only has an effect on RGB and RGBA pixels.
+ */
+static void
+image_transform_png_set_bgr_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_bgr(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_bgr_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_RGB ||
+       that->colour_type == PNG_COLOR_TYPE_RGBA)
+       that->swap_rgb = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_bgr_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return colour_type == PNG_COLOR_TYPE_RGB ||
+       colour_type == PNG_COLOR_TYPE_RGBA;
+}
+
+IT(bgr);
+#undef PT
+#define PT ITSTRUCT(bgr)
+
+#endif /* PNG_READ_BGR_SUPPORTED */
+
+/* png_set_swap_alpha */
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+/* Put the alpha channel first.
+ *
+ *  png_set_swap_alpha(png_structrp png_ptr)
+ *
+ * This only has an effect on GA and RGBA pixels.
+ */
+static void
+image_transform_png_set_swap_alpha_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_swap_alpha(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_swap_alpha_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_GA ||
+       that->colour_type == PNG_COLOR_TYPE_RGBA)
+      that->alpha_first = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_swap_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return colour_type == PNG_COLOR_TYPE_GA ||
+       colour_type == PNG_COLOR_TYPE_RGBA;
+}
+
+IT(swap_alpha);
+#undef PT
+#define PT ITSTRUCT(swap_alpha)
+
+#endif /* PNG_READ_SWAP_ALPHA_SUPPORTED */
+
+/* png_set_swap */
+#ifdef PNG_READ_SWAP_SUPPORTED
+/* Byte swap 16-bit components.
+ *
+ *  png_set_swap(png_structrp png_ptr)
+ */
+static void
+image_transform_png_set_swap_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_swap(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_swap_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth == 16)
+      that->swap16 = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_swap_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   return bit_depth == 16;
+}
+
+IT(swap);
+#undef PT
+#define PT ITSTRUCT(swap)
+
+#endif /* PNG_READ_SWAP_SUPPORTED */
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+/* Add a filler byte to 8-bit Gray or 24-bit RGB images.
+ *
+ *  png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags));
+ *
+ * Flags:
+ *
+ *  PNG_FILLER_BEFORE
+ *  PNG_FILLER_AFTER
+ */
+#define data ITDATA(filler)
+static struct
+{
+   png_uint_32 filler;
+   int         flags;
+} data;
+
+static void
+image_transform_png_set_filler_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   /* Need a random choice for 'before' and 'after' as well as for the
+    * filler.  The 'filler' value has all 32 bits set, but only bit_depth
+    * will be used.  At this point we don't know bit_depth.
+    */
+   data.filler = random_u32();
+   data.flags = random_choice();
+
+   png_set_filler(pp, data.filler, data.flags);
+
+   /* The standard display handling stuff also needs to know that
+    * there is a filler, so set that here.
+    */
+   that->this.filler = 1;
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_filler_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth >= 8 &&
+       (that->colour_type == PNG_COLOR_TYPE_RGB ||
+        that->colour_type == PNG_COLOR_TYPE_GRAY))
+   {
+      unsigned int max = (1U << that->bit_depth)-1;
+      that->alpha = data.filler & max;
+      that->alphaf = ((double)that->alpha) / max;
+      that->alphae = 0;
+
+      /* The filler has been stored in the alpha channel, we must record
+       * that this has been done for the checking later on, the color
+       * type is faked to have an alpha channel, but libpng won't report
+       * this; the app has to know the extra channel is there and this
+       * was recording in standard_display::filler above.
+       */
+      that->colour_type |= 4; /* alpha added */
+      that->alpha_first = data.flags == PNG_FILLER_BEFORE;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_filler_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   this->next = *that;
+   *that = this;
+
+   return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
+           colour_type == PNG_COLOR_TYPE_GRAY);
+}
+
+#undef data
+IT(filler);
+#undef PT
+#define PT ITSTRUCT(filler)
+
+/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
+/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
+#define data ITDATA(add_alpha)
+static struct
+{
+   png_uint_32 filler;
+   int         flags;
+} data;
+
+static void
+image_transform_png_set_add_alpha_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   /* Need a random choice for 'before' and 'after' as well as for the
+    * filler.  The 'filler' value has all 32 bits set, but only bit_depth
+    * will be used.  At this point we don't know bit_depth.
+    */
+   data.filler = random_u32();
+   data.flags = random_choice();
+
+   png_set_add_alpha(pp, data.filler, data.flags);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_add_alpha_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth >= 8 &&
+       (that->colour_type == PNG_COLOR_TYPE_RGB ||
+        that->colour_type == PNG_COLOR_TYPE_GRAY))
+   {
+      unsigned int max = (1U << that->bit_depth)-1;
+      that->alpha = data.filler & max;
+      that->alphaf = ((double)that->alpha) / max;
+      that->alphae = 0;
+
+      that->colour_type |= 4; /* alpha added */
+      that->alpha_first = data.flags == PNG_FILLER_BEFORE;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_add_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   this->next = *that;
+   *that = this;
+
+   return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
+           colour_type == PNG_COLOR_TYPE_GRAY);
+}
+
+#undef data
+IT(add_alpha);
+#undef PT
+#define PT ITSTRUCT(add_alpha)
+
+#endif /* PNG_READ_FILLER_SUPPORTED */
+
+/* png_set_packing */
+#ifdef PNG_READ_PACK_SUPPORTED
+/* Use 1 byte per pixel in 1, 2, or 4-bit depth files.
+ *
+ *  png_set_packing(png_structrp png_ptr)
+ *
+ * This should only affect grayscale and palette images with less than 8 bits
+ * per pixel.
+ */
+static void
+image_transform_png_set_packing_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_packing(pp);
+   that->unpacked = 1;
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_packing_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* The general expand case depends on what the colour type is,
+    * low bit-depth pixel values are unpacked into bytes without
+    * scaling, so sample_depth is not changed.
+    */
+   if (that->bit_depth < 8) /* grayscale or palette */
+      that->bit_depth = 8;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_packing_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   /* Nothing should happen unless the bit depth is less than 8: */
+   return bit_depth < 8;
+}
+
+IT(packing);
+#undef PT
+#define PT ITSTRUCT(packing)
+
+#endif /* PNG_READ_PACK_SUPPORTED */
+
+/* png_set_packswap */
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+/* Swap pixels packed into bytes; reverses the order on screen so that
+ * the high order bits correspond to the rightmost pixels.
+ *
+ *  png_set_packswap(png_structrp png_ptr)
+ */
+static void
+image_transform_png_set_packswap_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_packswap(pp);
+   that->this.littleendian = 1;
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_packswap_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth < 8)
+      that->littleendian = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_packswap_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   return bit_depth < 8;
+}
+
+IT(packswap);
+#undef PT
+#define PT ITSTRUCT(packswap)
+
+#endif /* PNG_READ_PACKSWAP_SUPPORTED */
+
+
+/* png_set_invert_mono */
+#ifdef PNG_READ_INVERT_MONO_SUPPORTED
+/* Invert the gray channel
+ *
+ *  png_set_invert_mono(png_structrp png_ptr)
+ */
+static void
+image_transform_png_set_invert_mono_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_invert_mono(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_invert_mono_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type & 4)
+      that->mono_inverted = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_invert_mono_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* Only has an effect on pixels with no colour: */
+   return (colour_type & 2) == 0;
+}
+
+IT(invert_mono);
+#undef PT
+#define PT ITSTRUCT(invert_mono)
+
+#endif /* PNG_READ_INVERT_MONO_SUPPORTED */
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+/* png_set_shift(png_structp, png_const_color_8p true_bits)
+ *
+ * The output pixels will be shifted by the given true_bits
+ * values.
+ */
+#define data ITDATA(shift)
+static png_color_8 data;
+
+static void
+image_transform_png_set_shift_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   /* Get a random set of shifts.  The shifts need to do something
+    * to test the transform, so they are limited to the bit depth
+    * of the input image.  Notice that in the following the 'gray'
+    * field is randomized independently.  This acts as a check that
+    * libpng does use the correct field.
+    */
+   unsigned int depth = that->this.bit_depth;
+
+   data.red = (png_byte)/*SAFE*/(random_mod(depth)+1);
+   data.green = (png_byte)/*SAFE*/(random_mod(depth)+1);
+   data.blue = (png_byte)/*SAFE*/(random_mod(depth)+1);
+   data.gray = (png_byte)/*SAFE*/(random_mod(depth)+1);
+   data.alpha = (png_byte)/*SAFE*/(random_mod(depth)+1);
+
+   png_set_shift(pp, &data);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_shift_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* Copy the correct values into the sBIT fields, libpng does not do
+    * anything to palette data:
+    */
+   if (that->colour_type != PNG_COLOR_TYPE_PALETTE)
+   {
+       that->sig_bits = 1;
+
+       /* The sBIT fields are reset to the values previously sent to
+        * png_set_shift according to the colour type.
+        * does.
+        */
+       if (that->colour_type & 2) /* RGB channels */
+       {
+          that->red_sBIT = data.red;
+          that->green_sBIT = data.green;
+          that->blue_sBIT = data.blue;
+       }
+
+       else /* One grey channel */
+          that->red_sBIT = that->green_sBIT = that->blue_sBIT = data.gray;
+
+       that->alpha_sBIT = data.alpha;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_shift_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return colour_type != PNG_COLOR_TYPE_PALETTE;
+}
+
+IT(shift);
+#undef PT
+#define PT ITSTRUCT(shift)
+
+#endif /* PNG_READ_SHIFT_SUPPORTED */
+
+#ifdef THIS_IS_THE_PROFORMA
+static void
+image_transform_png_set_@_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_@(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_@_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_@_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   this->next = *that;
+   *that = this;
+
+   return 1;
+}
+
+IT(@);
+#endif
+
+
+/* This may just be 'end' if all the transforms are disabled! */
+static image_transform *const image_transform_first = &PT;
+
+static void
+transform_enable(const char *name)
+{
+   /* Everything starts out enabled, so if we see an 'enable' disabled
+    * everything else the first time round.
+    */
+   static int all_disabled = 0;
+   int found_it = 0;
+   image_transform *list = image_transform_first;
+
+   while (list != &image_transform_end)
+   {
+      if (strcmp(list->name, name) == 0)
+      {
+         list->enable = 1;
+         found_it = 1;
+      }
+      else if (!all_disabled)
+         list->enable = 0;
+
+      list = list->list;
+   }
+
+   all_disabled = 1;
+
+   if (!found_it)
+   {
+      fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
+         name);
+      exit(99);
+   }
+}
+
+static void
+transform_disable(const char *name)
+{
+   image_transform *list = image_transform_first;
+
+   while (list != &image_transform_end)
+   {
+      if (strcmp(list->name, name) == 0)
+      {
+         list->enable = 0;
+         return;
+      }
+
+      list = list->list;
+   }
+
+   fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
+      name);
+   exit(99);
+}
+
+static void
+image_transform_reset_count(void)
+{
+   image_transform *next = image_transform_first;
+   int count = 0;
+
+   while (next != &image_transform_end)
+   {
+      next->local_use = 0;
+      next->next = 0;
+      next = next->list;
+      ++count;
+   }
+
+   /* This can only happen if we every have more than 32 transforms (excluding
+    * the end) in the list.
+    */
+   if (count > 32) abort();
+}
+
+static int
+image_transform_test_counter(png_uint_32 counter, unsigned int max)
+{
+   /* Test the list to see if there is any point contining, given a current
+    * counter and a 'max' value.
+    */
+   image_transform *next = image_transform_first;
+
+   while (next != &image_transform_end)
+   {
+      /* For max 0 or 1 continue until the counter overflows: */
+      counter >>= 1;
+
+      /* Continue if any entry hasn't reacked the max. */
+      if (max > 1 && next->local_use < max)
+         return 1;
+      next = next->list;
+   }
+
+   return max <= 1 && counter == 0;
+}
+
+static png_uint_32
+image_transform_add(const image_transform **this, unsigned int max,
+   png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
+   png_byte colour_type, png_byte bit_depth)
+{
+   for (;;) /* until we manage to add something */
+   {
+      png_uint_32 mask;
+      image_transform *list;
+
+      /* Find the next counter value, if the counter is zero this is the start
+       * of the list.  This routine always returns the current counter (not the
+       * next) so it returns 0 at the end and expects 0 at the beginning.
+       */
+      if (counter == 0) /* first time */
+      {
+         image_transform_reset_count();
+         if (max <= 1)
+            counter = 1;
+         else
+            counter = random_32();
+      }
+      else /* advance the counter */
+      {
+         switch (max)
+         {
+            case 0:  ++counter; break;
+            case 1:  counter <<= 1; break;
+            default: counter = random_32(); break;
+         }
+      }
+
+      /* Now add all these items, if possible */
+      *this = &image_transform_end;
+      list = image_transform_first;
+      mask = 1;
+
+      /* Go through the whole list adding anything that the counter selects: */
+      while (list != &image_transform_end)
+      {
+         if ((counter & mask) != 0 && list->enable &&
+             (max == 0 || list->local_use < max))
+         {
+            /* Candidate to add: */
+            if (list->add(list, this, colour_type, bit_depth) || max == 0)
+            {
+               /* Added, so add to the name too. */
+               *pos = safecat(name, sizeof_name, *pos, " +");
+               *pos = safecat(name, sizeof_name, *pos, list->name);
+            }
+
+            else
+            {
+               /* Not useful and max>0, so remove it from *this: */
+               *this = list->next;
+               list->next = 0;
+
+               /* And, since we know it isn't useful, stop it being added again
+                * in this run:
+                */
+               list->local_use = max;
+            }
+         }
+
+         mask <<= 1;
+         list = list->list;
+      }
+
+      /* Now if anything was added we have something to do. */
+      if (*this != &image_transform_end)
+         return counter;
+
+      /* Nothing added, but was there anything in there to add? */
+      if (!image_transform_test_counter(counter, max))
+         return 0;
+   }
+}
+
+static void
+perform_transform_test(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   while (next_format(&colour_type, &bit_depth, &palette_number, pm->test_lbg,
+            pm->test_tRNS))
+   {
+      png_uint_32 counter = 0;
+      size_t base_pos;
+      char name[64];
+
+      base_pos = safecat(name, sizeof name, 0, "transform:");
+
+      for (;;)
+      {
+         size_t pos = base_pos;
+         const image_transform *list = 0;
+
+         /* 'max' is currently hardwired to '1'; this should be settable on the
+          * command line.
+          */
+         counter = image_transform_add(&list, 1/*max*/, counter,
+            name, sizeof name, &pos, colour_type, bit_depth);
+
+         if (counter == 0)
+            break;
+
+         /* The command line can change this to checking interlaced images. */
+         do
+         {
+            pm->repeat = 0;
+            transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
+               pm->interlace_type, 0, 0, 0), list, name);
+
+            if (fail(pm))
+               return;
+         }
+         while (pm->repeat);
+      }
+   }
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+/********************************* GAMMA TESTS ********************************/
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Reader callbacks and implementations, where they differ from the standard
+ * ones.
+ */
+typedef struct gamma_display
+{
+   standard_display this;
+
+   /* Parameters */
+   png_modifier*    pm;
+   double           file_gamma;
+   double           screen_gamma;
+   double           background_gamma;
+   png_byte         sbit;
+   int              threshold_test;
+   int              use_input_precision;
+   int              scale16;
+   int              expand16;
+   int              do_background;
+   png_color_16     background_color;
+
+   /* Local variables */
+   double       maxerrout;
+   double       maxerrpc;
+   double       maxerrabs;
+} gamma_display;
+
+#define ALPHA_MODE_OFFSET 4
+
+static void
+gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
+    double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
+    int use_input_precision, int scale16, int expand16,
+    int do_background, const png_color_16 *pointer_to_the_background_color,
+    double background_gamma)
+{
+   /* Standard fields */
+   standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
+      pm->use_update_info);
+
+   /* Parameter fields */
+   dp->pm = pm;
+   dp->file_gamma = file_gamma;
+   dp->screen_gamma = screen_gamma;
+   dp->background_gamma = background_gamma;
+   dp->sbit = sbit;
+   dp->threshold_test = threshold_test;
+   dp->use_input_precision = use_input_precision;
+   dp->scale16 = scale16;
+   dp->expand16 = expand16;
+   dp->do_background = do_background;
+   if (do_background && pointer_to_the_background_color != 0)
+      dp->background_color = *pointer_to_the_background_color;
+   else
+      memset(&dp->background_color, 0, sizeof dp->background_color);
+
+   /* Local variable fields */
+   dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
+}
+
+static void
+gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
+{
+   /* Reuse the standard stuff as appropriate. */
+   standard_info_part1(&dp->this, pp, pi);
+
+   /* If requested strip 16 to 8 bits - this is handled automagically below
+    * because the output bit depth is read from the library.  Note that there
+    * are interactions with sBIT but, internally, libpng makes sbit at most
+    * PNG_MAX_GAMMA_8 prior to 1.7 when doing the following.
+    */
+   if (dp->scale16)
+#     ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+         png_set_scale_16(pp);
+#     else
+         /* The following works both in 1.5.4 and earlier versions: */
+#        ifdef PNG_READ_16_TO_8_SUPPORTED
+            png_set_strip_16(pp);
+#        else
+            png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
+#        endif
+#     endif
+
+   if (dp->expand16)
+#     ifdef PNG_READ_EXPAND_16_SUPPORTED
+         png_set_expand_16(pp);
+#     else
+         png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
+#     endif
+
+   if (dp->do_background >= ALPHA_MODE_OFFSET)
+   {
+#     ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      {
+         /* This tests the alpha mode handling, if supported. */
+         int mode = dp->do_background - ALPHA_MODE_OFFSET;
+
+         /* The gamma value is the output gamma, and is in the standard,
+          * non-inverted, representation.  It provides a default for the PNG file
+          * gamma, but since the file has a gAMA chunk this does not matter.
+          */
+         const double sg = dp->screen_gamma;
+#        ifndef PNG_FLOATING_POINT_SUPPORTED
+            png_fixed_point g = fix(sg);
+#        endif
+
+#        ifdef PNG_FLOATING_POINT_SUPPORTED
+            png_set_alpha_mode(pp, mode, sg);
+#        else
+            png_set_alpha_mode_fixed(pp, mode, g);
+#        endif
+
+         /* However, for the standard Porter-Duff algorithm the output defaults
+          * to be linear, so if the test requires non-linear output it must be
+          * corrected here.
+          */
+         if (mode == PNG_ALPHA_STANDARD && sg != 1)
+         {
+#           ifdef PNG_FLOATING_POINT_SUPPORTED
+               png_set_gamma(pp, sg, dp->file_gamma);
+#           else
+               png_fixed_point f = fix(dp->file_gamma);
+               png_set_gamma_fixed(pp, g, f);
+#           endif
+         }
+      }
+#     else
+         png_error(pp, "alpha mode handling not supported");
+#     endif
+   }
+
+   else
+   {
+      /* Set up gamma processing. */
+#     ifdef PNG_FLOATING_POINT_SUPPORTED
+         png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
+#     else
+      {
+         png_fixed_point s = fix(dp->screen_gamma);
+         png_fixed_point f = fix(dp->file_gamma);
+         png_set_gamma_fixed(pp, s, f);
+      }
+#     endif
+
+      if (dp->do_background)
+      {
+#     ifdef PNG_READ_BACKGROUND_SUPPORTED
+         /* NOTE: this assumes the caller provided the correct background gamma!
+          */
+         const double bg = dp->background_gamma;
+#        ifndef PNG_FLOATING_POINT_SUPPORTED
+            png_fixed_point g = fix(bg);
+#        endif
+
+#        ifdef PNG_FLOATING_POINT_SUPPORTED
+            png_set_background(pp, &dp->background_color, dp->do_background,
+               0/*need_expand*/, bg);
+#        else
+            png_set_background_fixed(pp, &dp->background_color,
+               dp->do_background, 0/*need_expand*/, g);
+#        endif
+#     else
+         png_error(pp, "png_set_background not supported");
+#     endif
+      }
+   }
+
+   {
+      int i = dp->this.use_update_info;
+      /* Always do one call, even if use_update_info is 0. */
+      do
+         png_read_update_info(pp, pi);
+      while (--i > 0);
+   }
+
+   /* Now we may get a different cbRow: */
+   standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
+}
+
+static void PNGCBAPI
+gamma_info(png_structp pp, png_infop pi)
+{
+   gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
+      pi);
+}
+
+/* Validate a single component value - the routine gets the input and output
+ * sample values as unscaled PNG component values along with a cache of all the
+ * information required to validate the values.
+ */
+typedef struct validate_info
+{
+   png_const_structp  pp;
+   gamma_display *dp;
+   png_byte sbit;
+   int use_input_precision;
+   int do_background;
+   int scale16;
+   unsigned int sbit_max;
+   unsigned int isbit_shift;
+   unsigned int outmax;
+
+   double gamma_correction; /* Overall correction required. */
+   double file_inverse;     /* Inverse of file gamma. */
+   double screen_gamma;
+   double screen_inverse;   /* Inverse of screen gamma. */
+
+   double background_red;   /* Linear background value, red or gray. */
+   double background_green;
+   double background_blue;
+
+   double maxabs;
+   double maxpc;
+   double maxcalc;
+   double maxout;
+   double maxout_total;     /* Total including quantization error */
+   double outlog;
+   int    outquant;
+}
+validate_info;
+
+static void
+init_validate_info(validate_info *vi, gamma_display *dp, png_const_structp pp,
+    int in_depth, int out_depth)
+{
+   unsigned int outmax = (1U<<out_depth)-1;
+
+   vi->pp = pp;
+   vi->dp = dp;
+
+   if (dp->sbit > 0 && dp->sbit < in_depth)
+   {
+      vi->sbit = dp->sbit;
+      vi->isbit_shift = in_depth - dp->sbit;
+   }
+
+   else
+   {
+      vi->sbit = (png_byte)in_depth;
+      vi->isbit_shift = 0;
+   }
+
+   vi->sbit_max = (1U << vi->sbit)-1;
+
+   /* This mimics the libpng threshold test, '0' is used to prevent gamma
+    * correction in the validation test.
+    */
+   vi->screen_gamma = dp->screen_gamma;
+   if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
+      vi->screen_gamma = vi->screen_inverse = 0;
+   else
+      vi->screen_inverse = 1/vi->screen_gamma;
+
+   vi->use_input_precision = dp->use_input_precision;
+   vi->outmax = outmax;
+   vi->maxabs = abserr(dp->pm, in_depth, out_depth);
+   vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
+   vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
+   vi->maxout = outerr(dp->pm, in_depth, out_depth);
+   vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
+   vi->maxout_total = vi->maxout + vi->outquant * .5;
+   vi->outlog = outlog(dp->pm, in_depth, out_depth);
+
+   if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
+      (dp->this.colour_type == 3 && dp->this.is_transparent) ||
+      ((dp->this.colour_type == 0 || dp->this.colour_type == 2) &&
+       dp->this.has_tRNS))
+   {
+      vi->do_background = dp->do_background;
+
+      if (vi->do_background != 0)
+      {
+         const double bg_inverse = 1/dp->background_gamma;
+         double r, g, b;
+
+         /* Caller must at least put the gray value into the red channel */
+         r = dp->background_color.red; r /= outmax;
+         g = dp->background_color.green; g /= outmax;
+         b = dp->background_color.blue; b /= outmax;
+
+#     if 0
+         /* libpng doesn't do this optimization, if we do pngvalid will fail.
+          */
+         if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
+#     endif
+         {
+            r = pow(r, bg_inverse);
+            g = pow(g, bg_inverse);
+            b = pow(b, bg_inverse);
+         }
+
+         vi->background_red = r;
+         vi->background_green = g;
+         vi->background_blue = b;
+      }
+   }
+   else /* Do not expect any background processing */
+      vi->do_background = 0;
+
+   if (vi->do_background == 0)
+      vi->background_red = vi->background_green = vi->background_blue = 0;
+
+   vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
+   if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
+      vi->gamma_correction = 0;
+
+   vi->file_inverse = 1/dp->file_gamma;
+   if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
+      vi->file_inverse = 0;
+
+   vi->scale16 = dp->scale16;
+}
+
+/* This function handles composition of a single non-alpha component.  The
+ * argument is the input sample value, in the range 0..1, and the alpha value.
+ * The result is the composed, linear, input sample.  If alpha is less than zero
+ * this is the alpha component and the function should not be called!
+ */
+static double
+gamma_component_compose(int do_background, double input_sample, double alpha,
+   double background, int *compose)
+{
+   switch (do_background)
+   {
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+      case PNG_BACKGROUND_GAMMA_SCREEN:
+      case PNG_BACKGROUND_GAMMA_FILE:
+      case PNG_BACKGROUND_GAMMA_UNIQUE:
+         /* Standard PNG background processing. */
+         if (alpha < 1)
+         {
+            if (alpha > 0)
+            {
+               input_sample = input_sample * alpha + background * (1-alpha);
+               if (compose != NULL)
+                  *compose = 1;
+            }
+
+            else
+               input_sample = background;
+         }
+         break;
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+         /* The components are premultiplied in either case and the output is
+          * gamma encoded (to get standard Porter-Duff we expect the output
+          * gamma to be set to 1.0!)
+          */
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+         /* The optimization is that the partial-alpha entries are linear
+          * while the opaque pixels are gamma encoded, but this only affects the
+          * output encoding.
+          */
+         if (alpha < 1)
+         {
+            if (alpha > 0)
+            {
+               input_sample *= alpha;
+               if (compose != NULL)
+                  *compose = 1;
+            }
+
+            else
+               input_sample = 0;
+         }
+         break;
+#endif
+
+      default:
+         /* Standard cases where no compositing is done (so the component
+          * value is already correct.)
+          */
+         UNUSED(alpha)
+         UNUSED(background)
+         UNUSED(compose)
+         break;
+   }
+
+   return input_sample;
+}
+
+/* This API returns the encoded *input* component, in the range 0..1 */
+static double
+gamma_component_validate(const char *name, const validate_info *vi,
+    unsigned int id, unsigned int od,
+    const double alpha /* <0 for the alpha channel itself */,
+    const double background /* component background value */)
+{
+   unsigned int isbit = id >> vi->isbit_shift;
+   unsigned int sbit_max = vi->sbit_max;
+   unsigned int outmax = vi->outmax;
+   int do_background = vi->do_background;
+
+   double i;
+
+   /* First check on the 'perfect' result obtained from the digitized input
+    * value, id, and compare this against the actual digitized result, 'od'.
+    * 'i' is the input result in the range 0..1:
+    */
+   i = isbit; i /= sbit_max;
+
+   /* Check for the fast route: if we don't do any background composition or if
+    * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
+    * just use the gamma_correction field to correct to the final output gamma.
+    */
+   if (alpha == 1 /* opaque pixel component */ || !do_background
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
+#endif
+      || (alpha < 0 /* alpha channel */
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
+#endif
+      ))
+   {
+      /* Then get the gamma corrected version of 'i' and compare to 'od', any
+       * error less than .5 is insignificant - just quantization of the output
+       * value to the nearest digital value (nevertheless the error is still
+       * recorded - it's interesting ;-)
+       */
+      double encoded_sample = i;
+      double encoded_error;
+
+      /* alpha less than 0 indicates the alpha channel, which is always linear
+       */
+      if (alpha >= 0 && vi->gamma_correction > 0)
+         encoded_sample = pow(encoded_sample, vi->gamma_correction);
+      encoded_sample *= outmax;
+
+      encoded_error = fabs(od-encoded_sample);
+
+      if (encoded_error > vi->dp->maxerrout)
+         vi->dp->maxerrout = encoded_error;
+
+      if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
+         return i;
+   }
+
+   /* The slow route - attempt to do linear calculations. */
+   /* There may be an error, or background processing is required, so calculate
+    * the actual sample values - unencoded light intensity values.  Note that in
+    * practice these are not completely unencoded because they include a
+    * 'viewing correction' to decrease or (normally) increase the perceptual
+    * contrast of the image.  There's nothing we can do about this - we don't
+    * know what it is - so assume the unencoded value is perceptually linear.
+    */
+   {
+      double input_sample = i; /* In range 0..1 */
+      double output, error, encoded_sample, encoded_error;
+      double es_lo, es_hi;
+      int compose = 0;           /* Set to one if composition done */
+      int output_is_encoded;     /* Set if encoded to screen gamma */
+      int log_max_error = 1;     /* Check maximum error values */
+      png_const_charp pass = 0;  /* Reason test passes (or 0 for fail) */
+
+      /* Convert to linear light (with the above caveat.)  The alpha channel is
+       * already linear.
+       */
+      if (alpha >= 0)
+      {
+         int tcompose;
+
+         if (vi->file_inverse > 0)
+            input_sample = pow(input_sample, vi->file_inverse);
+
+         /* Handle the compose processing: */
+         tcompose = 0;
+         input_sample = gamma_component_compose(do_background, input_sample,
+            alpha, background, &tcompose);
+
+         if (tcompose)
+            compose = 1;
+      }
+
+      /* And similarly for the output value, but we need to check the background
+       * handling to linearize it correctly.
+       */
+      output = od;
+      output /= outmax;
+
+      output_is_encoded = vi->screen_gamma > 0;
+
+      if (alpha < 0) /* The alpha channel */
+      {
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+         if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
+#endif
+         {
+            /* In all other cases the output alpha channel is linear already,
+             * don't log errors here, they are much larger in linear data.
+             */
+            output_is_encoded = 0;
+            log_max_error = 0;
+         }
+      }
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      else /* A component */
+      {
+         if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
+            alpha < 1) /* the optimized case - linear output */
+         {
+            if (alpha > 0) log_max_error = 0;
+            output_is_encoded = 0;
+         }
+      }
+#endif
+
+      if (output_is_encoded)
+         output = pow(output, vi->screen_gamma);
+
+      /* Calculate (or recalculate) the encoded_sample value and repeat the
+       * check above (unnecessary if we took the fast route, but harmless.)
+       */
+      encoded_sample = input_sample;
+      if (output_is_encoded)
+         encoded_sample = pow(encoded_sample, vi->screen_inverse);
+      encoded_sample *= outmax;
+
+      encoded_error = fabs(od-encoded_sample);
+
+      /* Don't log errors in the alpha channel, or the 'optimized' case,
+       * neither are significant to the overall perception.
+       */
+      if (log_max_error && encoded_error > vi->dp->maxerrout)
+         vi->dp->maxerrout = encoded_error;
+
+      if (encoded_error < vi->maxout_total)
+      {
+         if (encoded_error < vi->outlog)
+            return i;
+
+         /* Test passed but error is bigger than the log limit, record why the
+          * test passed:
+          */
+         pass = "less than maxout:\n";
+      }
+
+      /* i: the original input value in the range 0..1
+       *
+       * pngvalid calculations:
+       *  input_sample: linear result; i linearized and composed, range 0..1
+       *  encoded_sample: encoded result; input_sample scaled to output bit depth
+       *
+       * libpng calculations:
+       *  output: linear result; od scaled to 0..1 and linearized
+       *  od: encoded result from libpng
+       */
+
+      /* Now we have the numbers for real errors, both absolute values as as a
+       * percentage of the correct value (output):
+       */
+      error = fabs(input_sample-output);
+
+      if (log_max_error && error > vi->dp->maxerrabs)
+         vi->dp->maxerrabs = error;
+
+      /* The following is an attempt to ignore the tendency of quantization to
+       * dominate the percentage errors for lower result values:
+       */
+      if (log_max_error && input_sample > .5)
+      {
+         double percentage_error = error/input_sample;
+         if (percentage_error > vi->dp->maxerrpc)
+            vi->dp->maxerrpc = percentage_error;
+      }
+
+      /* Now calculate the digitization limits for 'encoded_sample' using the
+       * 'max' values.  Note that maxout is in the encoded space but maxpc and
+       * maxabs are in linear light space.
+       *
+       * First find the maximum error in linear light space, range 0..1:
+       */
+      {
+         double tmp = input_sample * vi->maxpc;
+         if (tmp < vi->maxabs) tmp = vi->maxabs;
+         /* If 'compose' is true the composition was done in linear space using
+          * integer arithmetic.  This introduces an extra error of +/- 0.5 (at
+          * least) in the integer space used.  'maxcalc' records this, taking
+          * into account the possibility that even for 16 bit output 8 bit space
+          * may have been used.
+          */
+         if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
+
+         /* The 'maxout' value refers to the encoded result, to compare with
+          * this encode input_sample adjusted by the maximum error (tmp) above.
+          */
+         es_lo = encoded_sample - vi->maxout;
+
+         if (es_lo > 0 && input_sample-tmp > 0)
+         {
+            double low_value = input_sample-tmp;
+            if (output_is_encoded)
+               low_value = pow(low_value, vi->screen_inverse);
+            low_value *= outmax;
+            if (low_value < es_lo) es_lo = low_value;
+
+            /* Quantize this appropriately: */
+            es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
+         }
+
+         else
+            es_lo = 0;
+
+         es_hi = encoded_sample + vi->maxout;
+
+         if (es_hi < outmax && input_sample+tmp < 1)
+         {
+            double high_value = input_sample+tmp;
+            if (output_is_encoded)
+               high_value = pow(high_value, vi->screen_inverse);
+            high_value *= outmax;
+            if (high_value > es_hi) es_hi = high_value;
+
+            es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
+         }
+
+         else
+            es_hi = outmax;
+      }
+
+      /* The primary test is that the final encoded value returned by the
+       * library should be between the two limits (inclusive) that were
+       * calculated above.
+       */
+      if (od >= es_lo && od <= es_hi)
+      {
+         /* The value passes, but we may need to log the information anyway. */
+         if (encoded_error < vi->outlog)
+            return i;
+
+         if (pass == 0)
+            pass = "within digitization limits:\n";
+      }
+
+      {
+         /* There has been an error in processing, or we need to log this
+          * value.
+          */
+         double is_lo, is_hi;
+
+         /* pass is set at this point if either of the tests above would have
+          * passed.  Don't do these additional tests here - just log the
+          * original [es_lo..es_hi] values.
+          */
+         if (pass == 0 && vi->use_input_precision && vi->dp->sbit)
+         {
+            /* Ok, something is wrong - this actually happens in current libpng
+             * 16-to-8 processing.  Assume that the input value (id, adjusted
+             * for sbit) can be anywhere between value-.5 and value+.5 - quite a
+             * large range if sbit is low.
+             *
+             * NOTE: at present because the libpng gamma table stuff has been
+             * changed to use a rounding algorithm to correct errors in 8-bit
+             * calculations the precise sbit calculation (a shift) has been
+             * lost.  This can result in up to a +/-1 error in the presence of
+             * an sbit less than the bit depth.
+             */
+#           if PNG_LIBPNG_VER < 10700
+#              define SBIT_ERROR .5
+#           else
+#              define SBIT_ERROR 1.
+#           endif
+            double tmp = (isbit - SBIT_ERROR)/sbit_max;
+
+            if (tmp <= 0)
+               tmp = 0;
+
+            else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
+               tmp = pow(tmp, vi->file_inverse);
+
+            tmp = gamma_component_compose(do_background, tmp, alpha, background,
+               NULL);
+
+            if (output_is_encoded && tmp > 0 && tmp < 1)
+               tmp = pow(tmp, vi->screen_inverse);
+
+            is_lo = ceil(outmax * tmp - vi->maxout_total);
+
+            if (is_lo < 0)
+               is_lo = 0;
+
+            tmp = (isbit + SBIT_ERROR)/sbit_max;
+
+            if (tmp >= 1)
+               tmp = 1;
+
+            else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
+               tmp = pow(tmp, vi->file_inverse);
+
+            tmp = gamma_component_compose(do_background, tmp, alpha, background,
+               NULL);
+
+            if (output_is_encoded && tmp > 0 && tmp < 1)
+               tmp = pow(tmp, vi->screen_inverse);
+
+            is_hi = floor(outmax * tmp + vi->maxout_total);
+
+            if (is_hi > outmax)
+               is_hi = outmax;
+
+            if (!(od < is_lo || od > is_hi))
+            {
+               if (encoded_error < vi->outlog)
+                  return i;
+
+               pass = "within input precision limits:\n";
+            }
+
+            /* One last chance.  If this is an alpha channel and the 16to8
+             * option has been used and 'inaccurate' scaling is used then the
+             * bit reduction is obtained by simply using the top 8 bits of the
+             * value.
+             *
+             * This is only done for older libpng versions when the 'inaccurate'
+             * (chop) method of scaling was used.
+             */
+#           ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+#              if PNG_LIBPNG_VER < 10504
+                  /* This may be required for other components in the future,
+                   * but at present the presence of gamma correction effectively
+                   * prevents the errors in the component scaling (I don't quite
+                   * understand why, but since it's better this way I care not
+                   * to ask, JB 20110419.)
+                   */
+                  if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
+                     vi->sbit + vi->isbit_shift == 16)
+                  {
+                     tmp = ((id >> 8) - .5)/255;
+
+                     if (tmp > 0)
+                     {
+                        is_lo = ceil(outmax * tmp - vi->maxout_total);
+                        if (is_lo < 0) is_lo = 0;
+                     }
+
+                     else
+                        is_lo = 0;
+
+                     tmp = ((id >> 8) + .5)/255;
+
+                     if (tmp < 1)
+                     {
+                        is_hi = floor(outmax * tmp + vi->maxout_total);
+                        if (is_hi > outmax) is_hi = outmax;
+                     }
+
+                     else
+                        is_hi = outmax;
+
+                     if (!(od < is_lo || od > is_hi))
+                     {
+                        if (encoded_error < vi->outlog)
+                           return i;
+
+                        pass = "within 8 bit limits:\n";
+                     }
+                  }
+#              endif
+#           endif
+         }
+         else /* !use_input_precision */
+            is_lo = es_lo, is_hi = es_hi;
+
+         /* Attempt to output a meaningful error/warning message: the message
+          * output depends on the background/composite operation being performed
+          * because this changes what parameters were actually used above.
+          */
+         {
+            size_t pos = 0;
+            /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
+             * places.  Just use outmax to work out which.
+             */
+            int precision = (outmax >= 1000 ? 6 : 3);
+            int use_input=1, use_background=0, do_compose=0;
+            char msg[256];
+
+            if (pass != 0)
+               pos = safecat(msg, sizeof msg, pos, "\n\t");
+
+            /* Set up the various flags, the output_is_encoded flag above
+             * is also used below.  do_compose is just a double check.
+             */
+            switch (do_background)
+            {
+#           ifdef PNG_READ_BACKGROUND_SUPPORTED
+               case PNG_BACKGROUND_GAMMA_SCREEN:
+               case PNG_BACKGROUND_GAMMA_FILE:
+               case PNG_BACKGROUND_GAMMA_UNIQUE:
+                  use_background = (alpha >= 0 && alpha < 1);
+#           endif
+#           ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+               /* FALLTHROUGH */
+               case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+               case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+               case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+#           endif /* ALPHA_MODE_SUPPORTED */
+               do_compose = (alpha > 0 && alpha < 1);
+               use_input = (alpha != 0);
+               break;
+
+            default:
+               break;
+            }
+
+            /* Check the 'compose' flag */
+            if (compose != do_compose)
+               png_error(vi->pp, "internal error (compose)");
+
+            /* 'name' is the component name */
+            pos = safecat(msg, sizeof msg, pos, name);
+            pos = safecat(msg, sizeof msg, pos, "(");
+            pos = safecatn(msg, sizeof msg, pos, id);
+            if (use_input || pass != 0/*logging*/)
+            {
+               if (isbit != id)
+               {
+                  /* sBIT has reduced the precision of the input: */
+                  pos = safecat(msg, sizeof msg, pos, ", sbit(");
+                  pos = safecatn(msg, sizeof msg, pos, vi->sbit);
+                  pos = safecat(msg, sizeof msg, pos, "): ");
+                  pos = safecatn(msg, sizeof msg, pos, isbit);
+               }
+               pos = safecat(msg, sizeof msg, pos, "/");
+               /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
+               pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
+            }
+            pos = safecat(msg, sizeof msg, pos, ")");
+
+            /* A component may have been multiplied (in linear space) by the
+             * alpha value, 'compose' says whether this is relevant.
+             */
+            if (compose || pass != 0)
+            {
+               /* If any form of composition is being done report our
+                * calculated linear value here (the code above doesn't record
+                * the input value before composition is performed, so what
+                * gets reported is the value after composition.)
+                */
+               if (use_input || pass != 0)
+               {
+                  if (vi->file_inverse > 0)
+                  {
+                     pos = safecat(msg, sizeof msg, pos, "^");
+                     pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
+                  }
+
+                  else
+                     pos = safecat(msg, sizeof msg, pos, "[linear]");
+
+                  pos = safecat(msg, sizeof msg, pos, "*(alpha)");
+                  pos = safecatd(msg, sizeof msg, pos, alpha, precision);
+               }
+
+               /* Now record the *linear* background value if it was used
+                * (this function is not passed the original, non-linear,
+                * value but it is contained in the test name.)
+                */
+               if (use_background)
+               {
+                  pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
+                  pos = safecat(msg, sizeof msg, pos, "(background)");
+                  pos = safecatd(msg, sizeof msg, pos, background, precision);
+                  pos = safecat(msg, sizeof msg, pos, "*");
+                  pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
+               }
+            }
+
+            /* Report the calculated value (input_sample) and the linearized
+             * libpng value (output) unless this is just a component gamma
+             * correction.
+             */
+            if (compose || alpha < 0 || pass != 0)
+            {
+               pos = safecat(msg, sizeof msg, pos,
+                  pass != 0 ? " =\n\t" : " = ");
+               pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
+               pos = safecat(msg, sizeof msg, pos, " (libpng: ");
+               pos = safecatd(msg, sizeof msg, pos, output, precision);
+               pos = safecat(msg, sizeof msg, pos, ")");
+
+               /* Finally report the output gamma encoding, if any. */
+               if (output_is_encoded)
+               {
+                  pos = safecat(msg, sizeof msg, pos, " ^");
+                  pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
+                  pos = safecat(msg, sizeof msg, pos, "(to screen) =");
+               }
+
+               else
+                  pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
+            }
+
+            if ((!compose && alpha >= 0) || pass != 0)
+            {
+               if (pass != 0) /* logging */
+                  pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
+
+               /* This is the non-composition case, the internal linear
+                * values are irrelevant (though the log below will reveal
+                * them.)  Output a much shorter warning/error message and report
+                * the overall gamma correction.
+                */
+               if (vi->gamma_correction > 0)
+               {
+                  pos = safecat(msg, sizeof msg, pos, " ^");
+                  pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
+                  pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
+               }
+
+               else
+                  pos = safecat(msg, sizeof msg, pos,
+                     " [no gamma correction] =");
+
+               if (pass != 0)
+                  pos = safecat(msg, sizeof msg, pos, "]");
+            }
+
+            /* This is our calculated encoded_sample which should (but does
+             * not) match od:
+             */
+            pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
+            pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
+            pos = safecat(msg, sizeof msg, pos, " < ");
+            pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
+            pos = safecat(msg, sizeof msg, pos, " (libpng: ");
+            pos = safecatn(msg, sizeof msg, pos, od);
+            pos = safecat(msg, sizeof msg, pos, ")");
+            pos = safecat(msg, sizeof msg, pos, "/");
+            pos = safecatn(msg, sizeof msg, pos, outmax);
+            pos = safecat(msg, sizeof msg, pos, " < ");
+            pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
+
+            if (pass == 0) /* The error condition */
+            {
+#              ifdef PNG_WARNINGS_SUPPORTED
+                  png_warning(vi->pp, msg);
+#              else
+                  store_warning(vi->pp, msg);
+#              endif
+            }
+
+            else /* logging this value */
+               store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
+         }
+      }
+   }
+
+   return i;
+}
+
+static void
+gamma_image_validate(gamma_display *dp, png_const_structp pp,
+   png_infop pi)
+{
+   /* Get some constants derived from the input and output file formats: */
+   const png_store* const ps = dp->this.ps;
+   png_byte in_ct = dp->this.colour_type;
+   png_byte in_bd = dp->this.bit_depth;
+   png_uint_32 w = dp->this.w;
+   png_uint_32 h = dp->this.h;
+   const size_t cbRow = dp->this.cbRow;
+   png_byte out_ct = png_get_color_type(pp, pi);
+   png_byte out_bd = png_get_bit_depth(pp, pi);
+
+   /* There are three sources of error, firstly the quantization in the
+    * file encoding, determined by sbit and/or the file depth, secondly
+    * the output (screen) gamma and thirdly the output file encoding.
+    *
+    * Since this API receives the screen and file gamma in double
+    * precision it is possible to calculate an exact answer given an input
+    * pixel value.  Therefore we assume that the *input* value is exact -
+    * sample/maxsample - calculate the corresponding gamma corrected
+    * output to the limits of double precision arithmetic and compare with
+    * what libpng returns.
+    *
+    * Since the library must quantize the output to 8 or 16 bits there is
+    * a fundamental limit on the accuracy of the output of +/-.5 - this
+    * quantization limit is included in addition to the other limits
+    * specified by the parameters to the API.  (Effectively, add .5
+    * everywhere.)
+    *
+    * The behavior of the 'sbit' parameter is defined by section 12.5
+    * (sample depth scaling) of the PNG spec.  That section forces the
+    * decoder to assume that the PNG values have been scaled if sBIT is
+    * present:
+    *
+    *     png-sample = floor( input-sample * (max-out/max-in) + .5);
+    *
+    * This means that only a subset of the possible PNG values should
+    * appear in the input. However, the spec allows the encoder to use a
+    * variety of approximations to the above and doesn't require any
+    * restriction of the values produced.
+    *
+    * Nevertheless the spec requires that the upper 'sBIT' bits of the
+    * value stored in a PNG file be the original sample bits.
+    * Consequently the code below simply scales the top sbit bits by
+    * (1<<sbit)-1 to obtain an original sample value.
+    *
+    * Because there is limited precision in the input it is arguable that
+    * an acceptable result is any valid result from input-.5 to input+.5.
+    * The basic tests below do not do this, however if 'use_input_precision'
+    * is set a subsequent test is performed above.
+    */
+   unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
+   int processing;
+   png_uint_32 y;
+   const store_palette_entry *in_palette = dp->this.palette;
+   int in_is_transparent = dp->this.is_transparent;
+   int process_tRNS;
+   int out_npalette = -1;
+   int out_is_transparent = 0; /* Just refers to the palette case */
+   store_palette out_palette;
+   validate_info vi;
+
+   /* Check for row overwrite errors */
+   store_image_check(dp->this.ps, pp, 0);
+
+   /* Supply the input and output sample depths here - 8 for an indexed image,
+    * otherwise the bit depth.
+    */
+   init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
+
+   processing = (vi.gamma_correction > 0 && !dp->threshold_test)
+      || in_bd != out_bd || in_ct != out_ct || vi.do_background;
+   process_tRNS = dp->this.has_tRNS && vi.do_background;
+
+   /* TODO: FIX THIS: MAJOR BUG!  If the transformations all happen inside
+    * the palette there is no way of finding out, because libpng fails to
+    * update the palette on png_read_update_info.  Indeed, libpng doesn't
+    * even do the required work until much later, when it doesn't have any
+    * info pointer.  Oops.  For the moment 'processing' is turned off if
+    * out_ct is palette.
+    */
+   if (in_ct == 3 && out_ct == 3)
+      processing = 0;
+
+   if (processing && out_ct == 3)
+      out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
+
+   for (y=0; y<h; ++y)
+   {
+      png_const_bytep pRow = store_image_row(ps, pp, 0, y);
+      png_byte std[STANDARD_ROWMAX];
+
+      transform_row(pp, std, in_ct, in_bd, y);
+
+      if (processing)
+      {
+         unsigned int x;
+
+         for (x=0; x<w; ++x)
+         {
+            double alpha = 1; /* serves as a flag value */
+
+            /* Record the palette index for index images. */
+            unsigned int in_index =
+               in_ct == 3 ? sample(std, 3, in_bd, x, 0, 0, 0) : 256;
+            unsigned int out_index =
+               out_ct == 3 ? sample(std, 3, out_bd, x, 0, 0, 0) : 256;
+
+            /* Handle input alpha - png_set_background will cause the output
+             * alpha to disappear so there is nothing to check.
+             */
+            if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 ||
+                (in_ct == 3 && in_is_transparent))
+            {
+               unsigned int input_alpha = in_ct == 3 ?
+                  dp->this.palette[in_index].alpha :
+                  sample(std, in_ct, in_bd, x, samples_per_pixel, 0, 0);
+
+               unsigned int output_alpha = 65536 /* as a flag value */;
+
+               if (out_ct == 3)
+               {
+                  if (out_is_transparent)
+                     output_alpha = out_palette[out_index].alpha;
+               }
+
+               else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
+                  output_alpha = sample(pRow, out_ct, out_bd, x,
+                     samples_per_pixel, 0, 0);
+
+               if (output_alpha != 65536)
+                  alpha = gamma_component_validate("alpha", &vi, input_alpha,
+                     output_alpha, -1/*alpha*/, 0/*background*/);
+
+               else /* no alpha in output */
+               {
+                  /* This is a copy of the calculation of 'i' above in order to
+                   * have the alpha value to use in the background calculation.
+                   */
+                  alpha = input_alpha >> vi.isbit_shift;
+                  alpha /= vi.sbit_max;
+               }
+            }
+
+            else if (process_tRNS)
+            {
+               /* alpha needs to be set appropriately for this pixel, it is
+                * currently 1 and needs to be 0 for an input pixel which matches
+                * the values in tRNS.
+                */
+               switch (in_ct)
+               {
+                  case 0: /* gray */
+                     if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
+                           dp->this.transparent.red)
+                        alpha = 0;
+                     break;
+
+                  case 2: /* RGB */
+                     if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
+                           dp->this.transparent.red &&
+                         sample(std, in_ct, in_bd, x, 1, 0, 0) ==
+                           dp->this.transparent.green &&
+                         sample(std, in_ct, in_bd, x, 2, 0, 0) ==
+                           dp->this.transparent.blue)
+                        alpha = 0;
+                     break;
+
+                  default:
+                     break;
+               }
+            }
+
+            /* Handle grayscale or RGB components. */
+            if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
+               (void)gamma_component_validate("gray", &vi,
+                  sample(std, in_ct, in_bd, x, 0, 0, 0),
+                  sample(pRow, out_ct, out_bd, x, 0, 0, 0),
+                  alpha/*component*/, vi.background_red);
+            else /* RGB or palette */
+            {
+               (void)gamma_component_validate("red", &vi,
+                  in_ct == 3 ? in_palette[in_index].red :
+                     sample(std, in_ct, in_bd, x, 0, 0, 0),
+                  out_ct == 3 ? out_palette[out_index].red :
+                     sample(pRow, out_ct, out_bd, x, 0, 0, 0),
+                  alpha/*component*/, vi.background_red);
+
+               (void)gamma_component_validate("green", &vi,
+                  in_ct == 3 ? in_palette[in_index].green :
+                     sample(std, in_ct, in_bd, x, 1, 0, 0),
+                  out_ct == 3 ? out_palette[out_index].green :
+                     sample(pRow, out_ct, out_bd, x, 1, 0, 0),
+                  alpha/*component*/, vi.background_green);
+
+               (void)gamma_component_validate("blue", &vi,
+                  in_ct == 3 ? in_palette[in_index].blue :
+                     sample(std, in_ct, in_bd, x, 2, 0, 0),
+                  out_ct == 3 ? out_palette[out_index].blue :
+                     sample(pRow, out_ct, out_bd, x, 2, 0, 0),
+                  alpha/*component*/, vi.background_blue);
+            }
+         }
+      }
+
+      else if (memcmp(std, pRow, cbRow) != 0)
+      {
+         char msg[64];
+
+         /* No transform is expected on the threshold tests. */
+         sprintf(msg, "gamma: below threshold row %lu changed",
+            (unsigned long)y);
+
+         png_error(pp, msg);
+      }
+   } /* row (y) loop */
+
+   dp->this.ps->validated = 1;
+}
+
+static void PNGCBAPI
+gamma_end(png_structp ppIn, png_infop pi)
+{
+   png_const_structp pp = ppIn;
+   gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
+
+   if (!dp->this.speed)
+      gamma_image_validate(dp, pp, pi);
+   else
+      dp->this.ps->validated = 1;
+}
+
+/* A single test run checking a gamma transformation.
+ *
+ * maxabs: maximum absolute error as a fraction
+ * maxout: maximum output error in the output units
+ * maxpc:  maximum percentage error (as a percentage)
+ */
+static void
+gamma_test(png_modifier *pmIn, png_byte colour_typeIn,
+    png_byte bit_depthIn, int palette_numberIn,
+    int interlace_typeIn,
+    const double file_gammaIn, const double screen_gammaIn,
+    png_byte sbitIn, int threshold_testIn,
+    const char *name,
+    int use_input_precisionIn, int scale16In,
+    int expand16In, int do_backgroundIn,
+    const png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
+{
+   gamma_display d;
+   context(&pmIn->this, fault);
+
+   gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
+      palette_numberIn, interlace_typeIn, 0, 0, 0),
+      file_gammaIn, screen_gammaIn, sbitIn,
+      threshold_testIn, use_input_precisionIn, scale16In,
+      expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
+
+   Try
+   {
+      png_structp pp;
+      png_infop pi;
+      gama_modification gama_mod;
+      srgb_modification srgb_mod;
+      sbit_modification sbit_mod;
+
+      /* For the moment don't use the png_modifier support here. */
+      d.pm->encoding_counter = 0;
+      modifier_set_encoding(d.pm); /* Just resets everything */
+      d.pm->current_gamma = d.file_gamma;
+
+      /* Make an appropriate modifier to set the PNG file gamma to the
+       * given gamma value and the sBIT chunk to the given precision.
+       */
+      d.pm->modifications = NULL;
+      gama_modification_init(&gama_mod, d.pm, d.file_gamma);
+      srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
+      if (d.sbit > 0)
+         sbit_modification_init(&sbit_mod, d.pm, d.sbit);
+
+      modification_reset(d.pm->modifications);
+
+      /* Get a png_struct for reading the image. */
+      pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
+      standard_palette_init(&d.this);
+
+      /* Introduce the correct read function. */
+      if (d.pm->this.progressive)
+      {
+         /* Share the row function with the standard implementation. */
+         png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
+            gamma_end);
+
+         /* Now feed data into the reader until we reach the end: */
+         modifier_progressive_read(d.pm, pp, pi);
+      }
+      else
+      {
+         /* modifier_read expects a png_modifier* */
+         png_set_read_fn(pp, d.pm, modifier_read);
+
+         /* Check the header values: */
+         png_read_info(pp, pi);
+
+         /* Process the 'info' requirements. Only one image is generated */
+         gamma_info_imp(&d, pp, pi);
+
+         sequential_row(&d.this, pp, pi, -1, 0);
+
+         if (!d.this.speed)
+            gamma_image_validate(&d, pp, pi);
+         else
+            d.this.ps->validated = 1;
+      }
+
+      modifier_reset(d.pm);
+
+      if (d.pm->log && !d.threshold_test && !d.this.speed)
+         fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
+            d.this.bit_depth, colour_types[d.this.colour_type], name,
+            d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
+
+      /* Log the summary values too. */
+      if (d.this.colour_type == 0 || d.this.colour_type == 4)
+      {
+         switch (d.this.bit_depth)
+         {
+         case 1:
+            break;
+
+         case 2:
+            if (d.maxerrout > d.pm->error_gray_2)
+               d.pm->error_gray_2 = d.maxerrout;
+
+            break;
+
+         case 4:
+            if (d.maxerrout > d.pm->error_gray_4)
+               d.pm->error_gray_4 = d.maxerrout;
+
+            break;
+
+         case 8:
+            if (d.maxerrout > d.pm->error_gray_8)
+               d.pm->error_gray_8 = d.maxerrout;
+
+            break;
+
+         case 16:
+            if (d.maxerrout > d.pm->error_gray_16)
+               d.pm->error_gray_16 = d.maxerrout;
+
+            break;
+
+         default:
+            png_error(pp, "bad bit depth (internal: 1)");
+         }
+      }
+
+      else if (d.this.colour_type == 2 || d.this.colour_type == 6)
+      {
+         switch (d.this.bit_depth)
+         {
+         case 8:
+
+            if (d.maxerrout > d.pm->error_color_8)
+               d.pm->error_color_8 = d.maxerrout;
+
+            break;
+
+         case 16:
+
+            if (d.maxerrout > d.pm->error_color_16)
+               d.pm->error_color_16 = d.maxerrout;
+
+            break;
+
+         default:
+            png_error(pp, "bad bit depth (internal: 2)");
+         }
+      }
+
+      else if (d.this.colour_type == 3)
+      {
+         if (d.maxerrout > d.pm->error_indexed)
+            d.pm->error_indexed = d.maxerrout;
+      }
+   }
+
+   Catch(fault)
+      modifier_reset(voidcast(png_modifier*,(void*)fault));
+}
+
+static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
+    png_byte bit_depth, int interlace_type, double file_gamma,
+    double screen_gamma)
+{
+   size_t pos = 0;
+   char name[64];
+   pos = safecat(name, sizeof name, pos, "threshold ");
+   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+   pos = safecat(name, sizeof name, pos, "/");
+   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+
+   (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
+      file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
+      0 /*no input precision*/,
+      0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
+      0 /*no background gamma*/);
+}
+
+static void
+perform_gamma_threshold_tests(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   /* Don't test more than one instance of each palette - it's pointless, in
+    * fact this test is somewhat excessive since libpng doesn't make this
+    * decision based on colour type or bit depth!
+    *
+    * CHANGED: now test two palettes and, as a side effect, images with and
+    * without tRNS.
+    */
+   while (next_format(&colour_type, &bit_depth, &palette_number,
+                      pm->test_lbg_gamma_threshold, pm->test_tRNS))
+      if (palette_number < 2)
+   {
+      double test_gamma = 1.0;
+      while (test_gamma >= .4)
+      {
+         /* There's little point testing the interlacing vs non-interlacing,
+          * but this can be set from the command line.
+          */
+         gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
+            test_gamma, 1/test_gamma);
+         test_gamma *= .95;
+      }
+
+      /* And a special test for sRGB */
+      gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
+          .45455, 2.2);
+
+      if (fail(pm))
+         return;
+   }
+}
+
+static void gamma_transform_test(png_modifier *pm,
+   png_byte colour_type, png_byte bit_depth,
+   int palette_number,
+   int interlace_type, const double file_gamma,
+   const double screen_gamma, png_byte sbit,
+   int use_input_precision, int scale16)
+{
+   size_t pos = 0;
+   char name[64];
+
+   if (sbit != bit_depth && sbit != 0)
+   {
+      pos = safecat(name, sizeof name, pos, "sbit(");
+      pos = safecatn(name, sizeof name, pos, sbit);
+      pos = safecat(name, sizeof name, pos, ") ");
+   }
+
+   else
+      pos = safecat(name, sizeof name, pos, "gamma ");
+
+   if (scale16)
+      pos = safecat(name, sizeof name, pos, "16to8 ");
+
+   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+   pos = safecat(name, sizeof name, pos, "->");
+   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+
+   gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
+      file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
+      scale16, pm->test_gamma_expand16, 0 , 0, 0);
+}
+
+static void perform_gamma_transform_tests(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   while (next_format(&colour_type, &bit_depth, &palette_number,
+                      pm->test_lbg_gamma_transform, pm->test_tRNS))
+   {
+      unsigned int i, j;
+
+      for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
+         if (i != j)
+         {
+            gamma_transform_test(pm, colour_type, bit_depth, palette_number,
+               pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], 0/*sBIT*/,
+               pm->use_input_precision, 0 /*do not scale16*/);
+
+            if (fail(pm))
+               return;
+         }
+   }
+}
+
+static void perform_gamma_sbit_tests(png_modifier *pm)
+{
+   png_byte sbit;
+
+   /* The only interesting cases are colour and grayscale, alpha is ignored here
+    * for overall speed.  Only bit depths where sbit is less than the bit depth
+    * are tested.
+    */
+   for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
+   {
+      png_byte colour_type = 0, bit_depth = 0;
+      unsigned int npalette = 0;
+
+      while (next_format(&colour_type, &bit_depth, &npalette,
+                         pm->test_lbg_gamma_sbit, pm->test_tRNS))
+         if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
+            ((colour_type == 3 && sbit < 8) ||
+            (colour_type != 3 && sbit < bit_depth)))
+      {
+         unsigned int i;
+
+         for (i=0; i<pm->ngamma_tests; ++i)
+         {
+            unsigned int j;
+
+            for (j=0; j<pm->ngamma_tests; ++j) if (i != j)
+            {
+               gamma_transform_test(pm, colour_type, bit_depth, npalette,
+                  pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
+                  sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
+
+               if (fail(pm))
+                  return;
+            }
+         }
+      }
+   }
+}
+
+/* Note that this requires a 16 bit source image but produces 8 bit output, so
+ * we only need the 16bit write support, but the 16 bit images are only
+ * generated if DO_16BIT is defined.
+ */
+#ifdef DO_16BIT
+static void perform_gamma_scale16_tests(png_modifier *pm)
+{
+#  ifndef PNG_MAX_GAMMA_8
+#     define PNG_MAX_GAMMA_8 11
+#  endif
+#  if defined PNG_MAX_GAMMA_8 || PNG_LIBPNG_VER < 10700
+#     define SBIT_16_TO_8 PNG_MAX_GAMMA_8
+#  else
+#     define SBIT_16_TO_8 16
+#  endif
+   /* Include the alpha cases here. Note that sbit matches the internal value
+    * used by the library - otherwise we will get spurious errors from the
+    * internal sbit style approximation.
+    *
+    * The threshold test is here because otherwise the 16 to 8 conversion will
+    * proceed *without* gamma correction, and the tests above will fail (but not
+    * by much) - this could be fixed, it only appears with the -g option.
+    */
+   unsigned int i, j;
+   for (i=0; i<pm->ngamma_tests; ++i)
+   {
+      for (j=0; j<pm->ngamma_tests; ++j)
+      {
+         if (i != j &&
+             fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
+         {
+            gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+
+            if (fail(pm))
+               return;
+
+            gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+
+            if (fail(pm))
+               return;
+
+            gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+
+            if (fail(pm))
+               return;
+
+            gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+
+            if (fail(pm))
+               return;
+         }
+      }
+   }
+}
+#endif /* 16 to 8 bit conversion */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+static void gamma_composition_test(png_modifier *pm,
+   png_byte colour_type, png_byte bit_depth,
+   int palette_number,
+   int interlace_type, const double file_gamma,
+   const double screen_gamma,
+   int use_input_precision, int do_background,
+   int expand_16)
+{
+   size_t pos = 0;
+   png_const_charp base;
+   double bg;
+   char name[128];
+   png_color_16 background;
+
+   /* Make up a name and get an appropriate background gamma value. */
+   switch (do_background)
+   {
+      default:
+         base = "";
+         bg = 4; /* should not be used */
+         break;
+      case PNG_BACKGROUND_GAMMA_SCREEN:
+         base = " bckg(Screen):";
+         bg = 1/screen_gamma;
+         break;
+      case PNG_BACKGROUND_GAMMA_FILE:
+         base = " bckg(File):";
+         bg = file_gamma;
+         break;
+      case PNG_BACKGROUND_GAMMA_UNIQUE:
+         base = " bckg(Unique):";
+         /* This tests the handling of a unique value, the math is such that the
+          * value tends to be <1, but is neither screen nor file (even if they
+          * match!)
+          */
+         bg = (file_gamma + screen_gamma) / 3;
+         break;
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
+         base = " alpha(PNG)";
+         bg = 4; /* should not be used */
+         break;
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+         base = " alpha(Porter-Duff)";
+         bg = 4; /* should not be used */
+         break;
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+         base = " alpha(Optimized)";
+         bg = 4; /* should not be used */
+         break;
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+         base = " alpha(Broken)";
+         bg = 4; /* should not be used */
+         break;
+#endif
+   }
+
+   /* Use random background values - the background is always presented in the
+    * output space (8 or 16 bit components).
+    */
+   if (expand_16 || bit_depth == 16)
+   {
+      png_uint_32 r = random_32();
+
+      background.red = (png_uint_16)r;
+      background.green = (png_uint_16)(r >> 16);
+      r = random_32();
+      background.blue = (png_uint_16)r;
+      background.gray = (png_uint_16)(r >> 16);
+
+      /* In earlier libpng versions, those where DIGITIZE is set, any background
+       * gamma correction in the expand16 case was done using 8-bit gamma
+       * correction tables, resulting in larger errors.  To cope with those
+       * cases use a 16-bit background value which will handle this gamma
+       * correction.
+       */
+#     if DIGITIZE
+         if (expand_16 && (do_background == PNG_BACKGROUND_GAMMA_UNIQUE ||
+                           do_background == PNG_BACKGROUND_GAMMA_FILE) &&
+            fabs(bg*screen_gamma-1) > PNG_GAMMA_THRESHOLD)
+         {
+            /* The background values will be looked up in an 8-bit table to do
+             * the gamma correction, so only select values which are an exact
+             * match for the 8-bit table entries:
+             */
+            background.red = (png_uint_16)((background.red >> 8) * 257);
+            background.green = (png_uint_16)((background.green >> 8) * 257);
+            background.blue = (png_uint_16)((background.blue >> 8) * 257);
+            background.gray = (png_uint_16)((background.gray >> 8) * 257);
+         }
+#     endif
+   }
+
+   else /* 8 bit colors */
+   {
+      png_uint_32 r = random_32();
+
+      background.red = (png_byte)r;
+      background.green = (png_byte)(r >> 8);
+      background.blue = (png_byte)(r >> 16);
+      background.gray = (png_byte)(r >> 24);
+   }
+
+   background.index = 193; /* rgb(193,193,193) to detect errors */
+
+   if (!(colour_type & PNG_COLOR_MASK_COLOR))
+   {
+      /* Because, currently, png_set_background is always called with
+       * 'need_expand' false in this case and because the gamma test itself
+       * doesn't cause an expand to 8-bit for lower bit depths the colour must
+       * be reduced to the correct range.
+       */
+      if (bit_depth < 8)
+         background.gray &= (png_uint_16)((1U << bit_depth)-1);
+
+      /* Grayscale input, we do not convert to RGB (TBD), so we must set the
+       * background to gray - else libpng seems to fail.
+       */
+      background.red = background.green = background.blue = background.gray;
+   }
+
+   pos = safecat(name, sizeof name, pos, "gamma ");
+   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+   pos = safecat(name, sizeof name, pos, "->");
+   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+
+   pos = safecat(name, sizeof name, pos, base);
+   if (do_background < ALPHA_MODE_OFFSET)
+   {
+      /* Include the background color and gamma in the name: */
+      pos = safecat(name, sizeof name, pos, "(");
+      /* This assumes no expand gray->rgb - the current code won't handle that!
+       */
+      if (colour_type & PNG_COLOR_MASK_COLOR)
+      {
+         pos = safecatn(name, sizeof name, pos, background.red);
+         pos = safecat(name, sizeof name, pos, ",");
+         pos = safecatn(name, sizeof name, pos, background.green);
+         pos = safecat(name, sizeof name, pos, ",");
+         pos = safecatn(name, sizeof name, pos, background.blue);
+      }
+      else
+         pos = safecatn(name, sizeof name, pos, background.gray);
+      pos = safecat(name, sizeof name, pos, ")^");
+      pos = safecatd(name, sizeof name, pos, bg, 3);
+   }
+
+   gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
+      file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
+      0/*strip 16*/, expand_16, do_background, &background, bg);
+}
+
+
+static void
+perform_gamma_composition_tests(png_modifier *pm, int do_background,
+   int expand_16)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   /* Skip the non-alpha cases - there is no setting of a transparency colour at
+    * present.
+    *
+    * TODO: incorrect; the palette case sets tRNS and, now RGB and gray do,
+    * however the palette case fails miserably so is commented out below.
+    */
+   while (next_format(&colour_type, &bit_depth, &palette_number,
+                      pm->test_lbg_gamma_composition, pm->test_tRNS))
+      if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0
+#if 0 /* TODO: FIXME */
+          /*TODO: FIXME: this should work */
+          || colour_type == 3
+#endif
+          || (colour_type != 3 && palette_number != 0))
+   {
+      unsigned int i, j;
+
+      /* Don't skip the i==j case here - it's relevant. */
+      for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
+      {
+         gamma_composition_test(pm, colour_type, bit_depth, palette_number,
+            pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
+            pm->use_input_precision, do_background, expand_16);
+
+         if (fail(pm))
+            return;
+      }
+   }
+}
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
+
+static void
+init_gamma_errors(png_modifier *pm)
+{
+   /* Use -1 to catch tests that were not actually run */
+   pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = -1.;
+   pm->error_color_8 = -1.;
+   pm->error_indexed = -1.;
+   pm->error_gray_16 = pm->error_color_16 = -1.;
+}
+
+static void
+print_one(const char *leader, double err)
+{
+   if (err != -1.)
+      printf(" %s %.5f\n", leader, err);
+}
+
+static void
+summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth,
+   int indexed)
+{
+   fflush(stderr);
+
+   if (who)
+      printf("\nGamma correction with %s:\n", who);
+
+   else
+      printf("\nBasic gamma correction:\n");
+
+   if (low_bit_depth)
+   {
+      print_one(" 2 bit gray: ", pm->error_gray_2);
+      print_one(" 4 bit gray: ", pm->error_gray_4);
+      print_one(" 8 bit gray: ", pm->error_gray_8);
+      print_one(" 8 bit color:", pm->error_color_8);
+      if (indexed)
+         print_one(" indexed:    ", pm->error_indexed);
+   }
+
+   print_one("16 bit gray: ", pm->error_gray_16);
+   print_one("16 bit color:", pm->error_color_16);
+
+   fflush(stdout);
+}
+
+static void
+perform_gamma_test(png_modifier *pm, int summary)
+{
+   /*TODO: remove this*/
+   /* Save certain values for the temporary overrides below. */
+   unsigned int calculations_use_input_precision =
+      pm->calculations_use_input_precision;
+#  ifdef PNG_READ_BACKGROUND_SUPPORTED
+      double maxout8 = pm->maxout8;
+#  endif
+
+   /* First some arbitrary no-transform tests: */
+   if (!pm->this.speed && pm->test_gamma_threshold)
+   {
+      perform_gamma_threshold_tests(pm);
+
+      if (fail(pm))
+         return;
+   }
+
+   /* Now some real transforms. */
+   if (pm->test_gamma_transform)
+   {
+      if (summary)
+      {
+         fflush(stderr);
+         printf("Gamma correction error summary\n\n");
+         printf("The printed value is the maximum error in the pixel values\n");
+         printf("calculated by the libpng gamma correction code.  The error\n");
+         printf("is calculated as the difference between the output pixel\n");
+         printf("value (always an integer) and the ideal value from the\n");
+         printf("libpng specification (typically not an integer).\n\n");
+
+         printf("Expect this value to be less than .5 for 8 bit formats,\n");
+         printf("less than 1 for formats with fewer than 8 bits and a small\n");
+         printf("number (typically less than 5) for the 16 bit formats.\n");
+         printf("For performance reasons the value for 16 bit formats\n");
+         printf("increases when the image file includes an sBIT chunk.\n");
+         fflush(stdout);
+      }
+
+      init_gamma_errors(pm);
+      /*TODO: remove this.  Necessary because the current libpng
+       * implementation works in 8 bits:
+       */
+      if (pm->test_gamma_expand16)
+         pm->calculations_use_input_precision = 1;
+      perform_gamma_transform_tests(pm);
+      if (!calculations_use_input_precision)
+         pm->calculations_use_input_precision = 0;
+
+      if (summary)
+         summarize_gamma_errors(pm, 0/*who*/, 1/*low bit depth*/, 1/*indexed*/);
+
+      if (fail(pm))
+         return;
+   }
+
+   /* The sbit tests produce much larger errors: */
+   if (pm->test_gamma_sbit)
+   {
+      init_gamma_errors(pm);
+      perform_gamma_sbit_tests(pm);
+
+      if (summary)
+         summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U, 1/*indexed*/);
+
+      if (fail(pm))
+         return;
+   }
+
+#ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
+   if (pm->test_gamma_scale16)
+   {
+      /* The 16 to 8 bit strip operations: */
+      init_gamma_errors(pm);
+      perform_gamma_scale16_tests(pm);
+
+      if (summary)
+      {
+         fflush(stderr);
+         printf("\nGamma correction with 16 to 8 bit reduction:\n");
+         printf(" 16 bit gray:  %.5f\n", pm->error_gray_16);
+         printf(" 16 bit color: %.5f\n", pm->error_color_16);
+         fflush(stdout);
+      }
+
+      if (fail(pm))
+         return;
+   }
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+   if (pm->test_gamma_background)
+   {
+      init_gamma_errors(pm);
+
+      /*TODO: remove this.  Necessary because the current libpng
+       * implementation works in 8 bits:
+       */
+      if (pm->test_gamma_expand16)
+      {
+         pm->calculations_use_input_precision = 1;
+         pm->maxout8 = .499; /* because the 16 bit background is smashed */
+      }
+      perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
+         pm->test_gamma_expand16);
+      if (!calculations_use_input_precision)
+         pm->calculations_use_input_precision = 0;
+      pm->maxout8 = maxout8;
+
+      if (summary)
+         summarize_gamma_errors(pm, "background", 1, 0/*indexed*/);
+
+      if (fail(pm))
+         return;
+   }
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+   if (pm->test_gamma_alpha_mode)
+   {
+      int do_background;
+
+      init_gamma_errors(pm);
+
+      /*TODO: remove this.  Necessary because the current libpng
+       * implementation works in 8 bits:
+       */
+      if (pm->test_gamma_expand16)
+         pm->calculations_use_input_precision = 1;
+      for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
+         do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
+         ++do_background)
+         perform_gamma_composition_tests(pm, do_background,
+            pm->test_gamma_expand16);
+      if (!calculations_use_input_precision)
+         pm->calculations_use_input_precision = 0;
+
+      if (summary)
+         summarize_gamma_errors(pm, "alpha mode", 1, 0/*indexed*/);
+
+      if (fail(pm))
+         return;
+   }
+#endif
+}
+#endif /* PNG_READ_GAMMA_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED */
+
+/* INTERLACE MACRO VALIDATION */
+/* This is copied verbatim from the specification, it is simply the pass
+ * number in which each pixel in each 8x8 tile appears.  The array must
+ * be indexed adam7[y][x] and notice that the pass numbers are based at
+ * 1, not 0 - the base libpng uses.
+ */
+static const
+png_byte adam7[8][8] =
+{
+   { 1,6,4,6,2,6,4,6 },
+   { 7,7,7,7,7,7,7,7 },
+   { 5,6,5,6,5,6,5,6 },
+   { 7,7,7,7,7,7,7,7 },
+   { 3,6,4,6,3,6,4,6 },
+   { 7,7,7,7,7,7,7,7 },
+   { 5,6,5,6,5,6,5,6 },
+   { 7,7,7,7,7,7,7,7 }
+};
+
+/* This routine validates all the interlace support macros in png.h for
+ * a variety of valid PNG widths and heights.  It uses a number of similarly
+ * named internal routines that feed off the above array.
+ */
+static png_uint_32
+png_pass_start_row(int pass)
+{
+   int x, y;
+   ++pass;
+   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+      return y;
+   return 0xf;
+}
+
+static png_uint_32
+png_pass_start_col(int pass)
+{
+   int x, y;
+   ++pass;
+   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+      return x;
+   return 0xf;
+}
+
+static int
+png_pass_row_shift(int pass)
+{
+   int x, y, base=(-1), inc=8;
+   ++pass;
+   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+   {
+      if (base == (-1))
+         base = y;
+      else if (base == y)
+         {}
+      else if (inc == y-base)
+         base=y;
+      else if (inc == 8)
+         inc = y-base, base=y;
+      else if (inc != y-base)
+         return 0xff; /* error - more than one 'inc' value! */
+   }
+
+   if (base == (-1)) return 0xfe; /* error - no row in pass! */
+
+   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
+   switch (inc)
+   {
+case 2: return 1;
+case 4: return 2;
+case 8: return 3;
+default: break;
+   }
+
+   /* error - unrecognized 'inc' */
+   return (inc << 8) + 0xfd;
+}
+
+static int
+png_pass_col_shift(int pass)
+{
+   int x, y, base=(-1), inc=8;
+   ++pass;
+   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+   {
+      if (base == (-1))
+         base = x;
+      else if (base == x)
+         {}
+      else if (inc == x-base)
+         base=x;
+      else if (inc == 8)
+         inc = x-base, base=x;
+      else if (inc != x-base)
+         return 0xff; /* error - more than one 'inc' value! */
+   }
+
+   if (base == (-1)) return 0xfe; /* error - no row in pass! */
+
+   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
+   switch (inc)
+   {
+case 1: return 0; /* pass 7 has all the columns */
+case 2: return 1;
+case 4: return 2;
+case 8: return 3;
+default: break;
+   }
+
+   /* error - unrecognized 'inc' */
+   return (inc << 8) + 0xfd;
+}
+
+static png_uint_32
+png_row_from_pass_row(png_uint_32 yIn, int pass)
+{
+   /* By examination of the array: */
+   switch (pass)
+   {
+case 0: return yIn * 8;
+case 1: return yIn * 8;
+case 2: return yIn * 8 + 4;
+case 3: return yIn * 4;
+case 4: return yIn * 4 + 2;
+case 5: return yIn * 2;
+case 6: return yIn * 2 + 1;
+default: break;
+   }
+
+   return 0xff; /* bad pass number */
+}
+
+static png_uint_32
+png_col_from_pass_col(png_uint_32 xIn, int pass)
+{
+   /* By examination of the array: */
+   switch (pass)
+   {
+case 0: return xIn * 8;
+case 1: return xIn * 8 + 4;
+case 2: return xIn * 4;
+case 3: return xIn * 4 + 2;
+case 4: return xIn * 2;
+case 5: return xIn * 2 + 1;
+case 6: return xIn;
+default: break;
+   }
+
+   return 0xff; /* bad pass number */
+}
+
+static int
+png_row_in_interlace_pass(png_uint_32 y, int pass)
+{
+   /* Is row 'y' in pass 'pass'? */
+   int x;
+   y &= 7;
+   ++pass;
+   for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+      return 1;
+
+   return 0;
+}
+
+static int
+png_col_in_interlace_pass(png_uint_32 x, int pass)
+{
+   /* Is column 'x' in pass 'pass'? */
+   int y;
+   x &= 7;
+   ++pass;
+   for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+      return 1;
+
+   return 0;
+}
+
+static png_uint_32
+png_pass_rows(png_uint_32 height, int pass)
+{
+   png_uint_32 tiles = height>>3;
+   png_uint_32 rows = 0;
+   unsigned int x, y;
+
+   height &= 7;
+   ++pass;
+   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+   {
+      rows += tiles;
+      if (y < height) ++rows;
+      break; /* i.e. break the 'x', column, loop. */
+   }
+
+   return rows;
+}
+
+static png_uint_32
+png_pass_cols(png_uint_32 width, int pass)
+{
+   png_uint_32 tiles = width>>3;
+   png_uint_32 cols = 0;
+   unsigned int x, y;
+
+   width &= 7;
+   ++pass;
+   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+   {
+      cols += tiles;
+      if (x < width) ++cols;
+      break; /* i.e. break the 'y', row, loop. */
+   }
+
+   return cols;
+}
+
+static void
+perform_interlace_macro_validation(void)
+{
+   /* The macros to validate, first those that depend only on pass:
+    *
+    * PNG_PASS_START_ROW(pass)
+    * PNG_PASS_START_COL(pass)
+    * PNG_PASS_ROW_SHIFT(pass)
+    * PNG_PASS_COL_SHIFT(pass)
+    */
+   int pass;
+
+   for (pass=0; pass<7; ++pass)
+   {
+      png_uint_32 m, f, v;
+
+      m = PNG_PASS_START_ROW(pass);
+      f = png_pass_start_row(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
+         exit(99);
+      }
+
+      m = PNG_PASS_START_COL(pass);
+      f = png_pass_start_col(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
+         exit(99);
+      }
+
+      m = PNG_PASS_ROW_SHIFT(pass);
+      f = png_pass_row_shift(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
+         exit(99);
+      }
+
+      m = PNG_PASS_COL_SHIFT(pass);
+      f = png_pass_col_shift(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
+         exit(99);
+      }
+
+      /* Macros that depend on the image or sub-image height too:
+       *
+       * PNG_PASS_ROWS(height, pass)
+       * PNG_PASS_COLS(width, pass)
+       * PNG_ROW_FROM_PASS_ROW(yIn, pass)
+       * PNG_COL_FROM_PASS_COL(xIn, pass)
+       * PNG_ROW_IN_INTERLACE_PASS(y, pass)
+       * PNG_COL_IN_INTERLACE_PASS(x, pass)
+       */
+      for (v=0;;)
+      {
+         /* The first two tests overflow if the pass row or column is outside
+          * the possible range for a 32-bit result.  In fact the values should
+          * never be outside the range for a 31-bit result, but checking for 32
+          * bits here ensures that if an app uses a bogus pass row or column
+          * (just so long as it fits in a 32 bit integer) it won't get a
+          * possibly dangerous overflow.
+          */
+         /* First the base 0 stuff: */
+         if (v < png_pass_rows(0xFFFFFFFFU, pass))
+         {
+            m = PNG_ROW_FROM_PASS_ROW(v, pass);
+            f = png_row_from_pass_row(v, pass);
+            if (m != f)
+            {
+               fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
+                  v, pass, m, f);
+               exit(99);
+            }
+         }
+
+         if (v < png_pass_cols(0xFFFFFFFFU, pass))
+         {
+            m = PNG_COL_FROM_PASS_COL(v, pass);
+            f = png_col_from_pass_col(v, pass);
+            if (m != f)
+            {
+               fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
+                  v, pass, m, f);
+               exit(99);
+            }
+         }
+
+         m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
+         f = png_row_in_interlace_pass(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
+         }
+
+         m = PNG_COL_IN_INTERLACE_PASS(v, pass);
+         f = png_col_in_interlace_pass(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
+         }
+
+         /* Then the base 1 stuff: */
+         ++v;
+         m = PNG_PASS_ROWS(v, pass);
+         f = png_pass_rows(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
+         }
+
+         m = PNG_PASS_COLS(v, pass);
+         f = png_pass_cols(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
+         }
+
+         /* Move to the next v - the stepping algorithm starts skipping
+          * values above 1024.
+          */
+         if (v > 1024)
+         {
+            if (v == PNG_UINT_31_MAX)
+               break;
+
+            v = (v << 1) ^ v;
+            if (v >= PNG_UINT_31_MAX)
+               v = PNG_UINT_31_MAX-1;
+         }
+      }
+   }
+}
+
+/* Test color encodings. These values are back-calculated from the published
+ * chromaticities.  The values are accurate to about 14 decimal places; 15 are
+ * given.  These values are much more accurate than the ones given in the spec,
+ * which typically don't exceed 4 decimal places.  This allows testing of the
+ * libpng code to its theoretical accuracy of 4 decimal places.  (If pngvalid
+ * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
+ * more.)
+ *
+ * The png_modifier code assumes that encodings[0] is sRGB and treats it
+ * specially: do not change the first entry in this list!
+ */
+static const color_encoding test_encodings[] =
+{
+/* sRGB: must be first in this list! */
+/*gamma:*/ { 1/2.2,
+/*red:  */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
+/*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
+/*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
+/* Kodak ProPhoto (wide gamut) */
+/*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
+/*red:  */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
+/*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
+/*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
+/* Adobe RGB (1998) */
+/*gamma:*/ { 1/(2+51./256),
+/*red:  */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
+/*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
+/*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
+/* Adobe Wide Gamut RGB */
+/*gamma:*/ { 1/(2+51./256),
+/*red:  */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
+/*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
+/*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
+/* Fake encoding which selects just the green channel */
+/*gamma:*/ { 1.45/2.2, /* the 'Mac' gamma */
+/*red:  */ { 0.716500716779386, 0.000000000000000, 0.000000000000000 },
+/*green:*/ { 0.101020574397477, 1.000000000000000, 0.051211818965388 },
+/*blue: */ { 0.146774385252705, 0.000000000000000, 0.773892783545073} },
+};
+
+/* signal handler
+ *
+ * This attempts to trap signals and escape without crashing.  It needs a
+ * context pointer so that it can throw an exception (call longjmp) to recover
+ * from the condition; this is handled by making the png_modifier used by 'main'
+ * into a global variable.
+ */
+static png_modifier pm;
+
+static void signal_handler(int signum)
+{
+
+   size_t pos = 0;
+   char msg[64];
+
+   pos = safecat(msg, sizeof msg, pos, "caught signal: ");
+
+   switch (signum)
+   {
+      case SIGABRT:
+         pos = safecat(msg, sizeof msg, pos, "abort");
+         break;
+
+      case SIGFPE:
+         pos = safecat(msg, sizeof msg, pos, "floating point exception");
+         break;
+
+      case SIGILL:
+         pos = safecat(msg, sizeof msg, pos, "illegal instruction");
+         break;
+
+      case SIGINT:
+         pos = safecat(msg, sizeof msg, pos, "interrupt");
+         break;
+
+      case SIGSEGV:
+         pos = safecat(msg, sizeof msg, pos, "invalid memory access");
+         break;
+
+      case SIGTERM:
+         pos = safecat(msg, sizeof msg, pos, "termination request");
+         break;
+
+      default:
+         pos = safecat(msg, sizeof msg, pos, "unknown ");
+         pos = safecatn(msg, sizeof msg, pos, signum);
+         break;
+   }
+
+   store_log(&pm.this, NULL/*png_structp*/, msg, 1/*error*/);
+
+   /* And finally throw an exception so we can keep going, unless this is
+    * SIGTERM in which case stop now.
+    */
+   if (signum != SIGTERM)
+   {
+      struct exception_context *the_exception_context =
+         &pm.this.exception_context;
+
+      Throw &pm.this;
+   }
+
+   else
+      exit(1);
+}
+
+/* main program */
+int main(int argc, char **argv)
+{
+   int summary = 1;  /* Print the error summary at the end */
+   int memstats = 0; /* Print memory statistics at the end */
+
+   /* Create the given output file on success: */
+   const char *touch = NULL;
+
+   /* This is an array of standard gamma values (believe it or not I've seen
+    * every one of these mentioned somewhere.)
+    *
+    * In the following list the most useful values are first!
+    */
+   static double
+      gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
+
+   /* This records the command and arguments: */
+   size_t cp = 0;
+   char command[1024];
+
+   anon_context(&pm.this);
+
+   gnu_volatile(summary)
+   gnu_volatile(memstats)
+   gnu_volatile(touch)
+
+   /* Add appropriate signal handlers, just the ANSI specified ones: */
+   signal(SIGABRT, signal_handler);
+   signal(SIGFPE, signal_handler);
+   signal(SIGILL, signal_handler);
+   signal(SIGINT, signal_handler);
+   signal(SIGSEGV, signal_handler);
+   signal(SIGTERM, signal_handler);
+
+#ifdef HAVE_FEENABLEEXCEPT
+   /* Only required to enable FP exceptions on platforms where they start off
+    * disabled; this is not necessary but if it is not done pngvalid will likely
+    * end up ignoring FP conditions that other platforms fault.
+    */
+   feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
+#endif
+
+   modifier_init(&pm);
+
+   /* Preallocate the image buffer, because we know how big it needs to be,
+    * note that, for testing purposes, it is deliberately mis-aligned by tag
+    * bytes either side.  All rows have an additional five bytes of padding for
+    * overwrite checking.
+    */
+   store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
+
+   /* Don't give argv[0], it's normally some horrible libtool string: */
+   cp = safecat(command, sizeof command, cp, "pngvalid");
+
+   /* Default to error on warning: */
+   pm.this.treat_warnings_as_errors = 1;
+
+   /* Default assume_16_bit_calculations appropriately; this tells the checking
+    * code that 16-bit arithmetic is used for 8-bit samples when it would make a
+    * difference.
+    */
+   pm.assume_16_bit_calculations = PNG_LIBPNG_VER >= 10700;
+
+   /* Currently 16 bit expansion happens at the end of the pipeline, so the
+    * calculations are done in the input bit depth not the output.
+    *
+    * TODO: fix this
+    */
+   pm.calculations_use_input_precision = 1U;
+
+   /* Store the test gammas */
+   pm.gammas = gammas;
+   pm.ngammas = ARRAY_SIZE(gammas);
+   pm.ngamma_tests = 0; /* default to off */
+
+   /* Low bit depth gray images don't do well in the gamma tests, until
+    * this is fixed turn them off for some gamma cases:
+    */
+#  ifdef PNG_WRITE_tRNS_SUPPORTED
+      pm.test_tRNS = 1;
+#  endif
+   pm.test_lbg = PNG_LIBPNG_VER >= 10600;
+   pm.test_lbg_gamma_threshold = 1;
+   pm.test_lbg_gamma_transform = PNG_LIBPNG_VER >= 10600;
+   pm.test_lbg_gamma_sbit = 1;
+   pm.test_lbg_gamma_composition = PNG_LIBPNG_VER >= 10700;
+
+   /* And the test encodings */
+   pm.encodings = test_encodings;
+   pm.nencodings = ARRAY_SIZE(test_encodings);
+
+#  if PNG_LIBPNG_VER < 10700
+      pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
+#  else
+      pm.sbitlow = 1U;
+#  endif
+
+   /* The following allows results to pass if they correspond to anything in the
+    * transformed range [input-.5,input+.5]; this is is required because of the
+    * way libpng treates the 16_TO_8 flag when building the gamma tables in
+    * releases up to 1.6.0.
+    *
+    * TODO: review this
+    */
+   pm.use_input_precision_16to8 = 1U;
+   pm.use_input_precision_sbit = 1U; /* because libpng now rounds sBIT */
+
+   /* Some default values (set the behavior for 'make check' here).
+    * These values simply control the maximum error permitted in the gamma
+    * transformations.  The practical limits for human perception are described
+    * below (the setting for maxpc16), however for 8 bit encodings it isn't
+    * possible to meet the accepted capabilities of human vision - i.e. 8 bit
+    * images can never be good enough, regardless of encoding.
+    */
+   pm.maxout8 = .1;     /* Arithmetic error in *encoded* value */
+   pm.maxabs8 = .00005; /* 1/20000 */
+   pm.maxcalc8 = 1./255;  /* +/-1 in 8 bits for compose errors */
+   pm.maxpc8 = .499;    /* I.e., .499% fractional error */
+   pm.maxout16 = .499;  /* Error in *encoded* value */
+   pm.maxabs16 = .00005;/* 1/20000 */
+   pm.maxcalc16 =1./65535;/* +/-1 in 16 bits for compose errors */
+#  if PNG_LIBPNG_VER < 10700
+      pm.maxcalcG = 1./((1<<PNG_MAX_GAMMA_8)-1);
+#  else
+      pm.maxcalcG = 1./((1<<16)-1);
+#  endif
+
+   /* NOTE: this is a reasonable perceptual limit. We assume that humans can
+    * perceive light level differences of 1% over a 100:1 range, so we need to
+    * maintain 1 in 10000 accuracy (in linear light space), which is what the
+    * following guarantees.  It also allows significantly higher errors at
+    * higher 16 bit values, which is important for performance.  The actual
+    * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
+    * this is only allowed for values >38149 by the following:
+    */
+   pm.maxpc16 = .005;   /* I.e., 1/200% - 1/20000 */
+
+   /* Now parse the command line options. */
+   while (--argc >= 1)
+   {
+      int catmore = 0; /* Set if the argument has an argument. */
+
+      /* Record each argument for posterity: */
+      cp = safecat(command, sizeof command, cp, " ");
+      cp = safecat(command, sizeof command, cp, *++argv);
+
+      if (strcmp(*argv, "-v") == 0)
+         pm.this.verbose = 1;
+
+      else if (strcmp(*argv, "-l") == 0)
+         pm.log = 1;
+
+      else if (strcmp(*argv, "-q") == 0)
+         summary = pm.this.verbose = pm.log = 0;
+
+      else if (strcmp(*argv, "-w") == 0 ||
+               strcmp(*argv, "--strict") == 0)
+         pm.this.treat_warnings_as_errors = 1; /* NOTE: this is the default! */
+
+      else if (strcmp(*argv, "--nostrict") == 0)
+         pm.this.treat_warnings_as_errors = 0;
+
+      else if (strcmp(*argv, "--speed") == 0)
+         pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
+            summary = 0;
+
+      else if (strcmp(*argv, "--memory") == 0)
+         memstats = 1;
+
+      else if (strcmp(*argv, "--size") == 0)
+         pm.test_size = 1;
+
+      else if (strcmp(*argv, "--nosize") == 0)
+         pm.test_size = 0;
+
+      else if (strcmp(*argv, "--standard") == 0)
+         pm.test_standard = 1;
+
+      else if (strcmp(*argv, "--nostandard") == 0)
+         pm.test_standard = 0;
+
+      else if (strcmp(*argv, "--transform") == 0)
+         pm.test_transform = 1;
+
+      else if (strcmp(*argv, "--notransform") == 0)
+         pm.test_transform = 0;
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+      else if (strncmp(*argv, "--transform-disable=",
+         sizeof "--transform-disable") == 0)
+         {
+         pm.test_transform = 1;
+         transform_disable(*argv + sizeof "--transform-disable");
+         }
+
+      else if (strncmp(*argv, "--transform-enable=",
+         sizeof "--transform-enable") == 0)
+         {
+         pm.test_transform = 1;
+         transform_enable(*argv + sizeof "--transform-enable");
+         }
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+      else if (strcmp(*argv, "--gamma") == 0)
+         {
+         /* Just do two gamma tests here (2.2 and linear) for speed: */
+         pm.ngamma_tests = 2U;
+         pm.test_gamma_threshold = 1;
+         pm.test_gamma_transform = 1;
+         pm.test_gamma_sbit = 1;
+         pm.test_gamma_scale16 = 1;
+         pm.test_gamma_background = 1; /* composition */
+         pm.test_gamma_alpha_mode = 1;
+         }
+
+      else if (strcmp(*argv, "--nogamma") == 0)
+         pm.ngamma_tests = 0;
+
+      else if (strcmp(*argv, "--gamma-threshold") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
+
+      else if (strcmp(*argv, "--nogamma-threshold") == 0)
+         pm.test_gamma_threshold = 0;
+
+      else if (strcmp(*argv, "--gamma-transform") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
+
+      else if (strcmp(*argv, "--nogamma-transform") == 0)
+         pm.test_gamma_transform = 0;
+
+      else if (strcmp(*argv, "--gamma-sbit") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
+
+      else if (strcmp(*argv, "--nogamma-sbit") == 0)
+         pm.test_gamma_sbit = 0;
+
+      else if (strcmp(*argv, "--gamma-16-to-8") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
+
+      else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
+         pm.test_gamma_scale16 = 0;
+
+      else if (strcmp(*argv, "--gamma-background") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
+
+      else if (strcmp(*argv, "--nogamma-background") == 0)
+         pm.test_gamma_background = 0;
+
+      else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
+
+      else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
+         pm.test_gamma_alpha_mode = 0;
+
+      else if (strcmp(*argv, "--expand16") == 0)
+         pm.test_gamma_expand16 = 1;
+
+      else if (strcmp(*argv, "--noexpand16") == 0)
+         pm.test_gamma_expand16 = 0;
+
+      else if (strcmp(*argv, "--low-depth-gray") == 0)
+         pm.test_lbg = pm.test_lbg_gamma_threshold =
+            pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
+            pm.test_lbg_gamma_composition = 1;
+
+      else if (strcmp(*argv, "--nolow-depth-gray") == 0)
+         pm.test_lbg = pm.test_lbg_gamma_threshold =
+            pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
+            pm.test_lbg_gamma_composition = 0;
+
+#     ifdef PNG_WRITE_tRNS_SUPPORTED
+         else if (strcmp(*argv, "--tRNS") == 0)
+            pm.test_tRNS = 1;
+#     endif
+
+      else if (strcmp(*argv, "--notRNS") == 0)
+         pm.test_tRNS = 0;
+
+      else if (strcmp(*argv, "--more-gammas") == 0)
+         pm.ngamma_tests = 3U;
+
+      else if (strcmp(*argv, "--all-gammas") == 0)
+         pm.ngamma_tests = pm.ngammas;
+
+      else if (strcmp(*argv, "--progressive-read") == 0)
+         pm.this.progressive = 1;
+
+      else if (strcmp(*argv, "--use-update-info") == 0)
+         ++pm.use_update_info; /* Can call multiple times */
+
+      else if (strcmp(*argv, "--interlace") == 0)
+      {
+#        if CAN_WRITE_INTERLACE
+            pm.interlace_type = PNG_INTERLACE_ADAM7;
+#        else /* !CAN_WRITE_INTERLACE */
+            fprintf(stderr, "pngvalid: no write interlace support\n");
+            return SKIP;
+#        endif /* !CAN_WRITE_INTERLACE */
+      }
+
+      else if (strcmp(*argv, "--use-input-precision") == 0)
+         pm.use_input_precision = 1U;
+
+      else if (strcmp(*argv, "--use-calculation-precision") == 0)
+         pm.use_input_precision = 0;
+
+      else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
+         pm.calculations_use_input_precision = 1U;
+
+      else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
+         pm.assume_16_bit_calculations = 1U;
+
+      else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
+         pm.calculations_use_input_precision =
+            pm.assume_16_bit_calculations = 0;
+
+      else if (strcmp(*argv, "--exhaustive") == 0)
+         pm.test_exhaustive = 1;
+
+      else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
+         --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
+
+      else if (argc > 1 && strcmp(*argv, "--touch") == 0)
+         --argc, touch = *++argv, catmore = 1;
+
+      else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
+      {
+         --argc;
+
+         if (strcmp(5+*argv, "abs8") == 0)
+            pm.maxabs8 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "abs16") == 0)
+            pm.maxabs16 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "calc8") == 0)
+            pm.maxcalc8 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "calc16") == 0)
+            pm.maxcalc16 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "out8") == 0)
+            pm.maxout8 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "out16") == 0)
+            pm.maxout16 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "pc8") == 0)
+            pm.maxpc8 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "pc16") == 0)
+            pm.maxpc16 = atof(*++argv);
+
+         else
+         {
+            fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
+            exit(99);
+         }
+
+         catmore = 1;
+      }
+
+      else if (strcmp(*argv, "--log8") == 0)
+         --argc, pm.log8 = atof(*++argv), catmore = 1;
+
+      else if (strcmp(*argv, "--log16") == 0)
+         --argc, pm.log16 = atof(*++argv), catmore = 1;
+
+#ifdef PNG_SET_OPTION_SUPPORTED
+      else if (strncmp(*argv, "--option=", 9) == 0)
+      {
+         /* Syntax of the argument is <option>:{on|off} */
+         const char *arg = 9+*argv;
+         unsigned char option=0, setting=0;
+
+#ifdef PNG_ARM_NEON
+         if (strncmp(arg, "arm-neon:", 9) == 0)
+            option = PNG_ARM_NEON, arg += 9;
+
+         else
+#endif
+#ifdef PNG_EXTENSIONS
+         if (strncmp(arg, "extensions:", 11) == 0)
+            option = PNG_EXTENSIONS, arg += 11;
+
+         else
+#endif
+#ifdef PNG_MAXIMUM_INFLATE_WINDOW
+         if (strncmp(arg, "max-inflate-window:", 19) == 0)
+            option = PNG_MAXIMUM_INFLATE_WINDOW, arg += 19;
+
+         else
+#endif
+         {
+            fprintf(stderr, "pngvalid: %s: %s: unknown option\n", *argv, arg);
+            exit(99);
+         }
+
+         if (strcmp(arg, "off") == 0)
+            setting = PNG_OPTION_OFF;
+
+         else if (strcmp(arg, "on") == 0)
+            setting = PNG_OPTION_ON;
+
+         else
+         {
+            fprintf(stderr,
+               "pngvalid: %s: %s: unknown setting (use 'on' or 'off')\n",
+               *argv, arg);
+            exit(99);
+         }
+
+         pm.this.options[pm.this.noptions].option = option;
+         pm.this.options[pm.this.noptions++].setting = setting;
+      }
+#endif /* PNG_SET_OPTION_SUPPORTED */
+
+      else
+      {
+         fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
+         exit(99);
+      }
+
+      if (catmore) /* consumed an extra *argv */
+      {
+         cp = safecat(command, sizeof command, cp, " ");
+         cp = safecat(command, sizeof command, cp, *argv);
+      }
+   }
+
+   /* If pngvalid is run with no arguments default to a reasonable set of the
+    * tests.
+    */
+   if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
+      pm.ngamma_tests == 0)
+   {
+      /* Make this do all the tests done in the test shell scripts with the same
+       * parameters, where possible.  The limitation is that all the progressive
+       * read and interlace stuff has to be done in separate runs, so only the
+       * basic 'standard' and 'size' tests are done.
+       */
+      pm.test_standard = 1;
+      pm.test_size = 1;
+      pm.test_transform = 1;
+      pm.ngamma_tests = 2U;
+   }
+
+   if (pm.ngamma_tests > 0 &&
+      pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
+      pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
+      pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
+   {
+      pm.test_gamma_threshold = 1;
+      pm.test_gamma_transform = 1;
+      pm.test_gamma_sbit = 1;
+      pm.test_gamma_scale16 = 1;
+      pm.test_gamma_background = 1;
+      pm.test_gamma_alpha_mode = 1;
+   }
+
+   else if (pm.ngamma_tests == 0)
+   {
+      /* Nothing to test so turn everything off: */
+      pm.test_gamma_threshold = 0;
+      pm.test_gamma_transform = 0;
+      pm.test_gamma_sbit = 0;
+      pm.test_gamma_scale16 = 0;
+      pm.test_gamma_background = 0;
+      pm.test_gamma_alpha_mode = 0;
+   }
+
+   Try
+   {
+      /* Make useful base images */
+      make_transform_images(&pm);
+
+      /* Perform the standard and gamma tests. */
+      if (pm.test_standard)
+      {
+         perform_interlace_macro_validation();
+         perform_formatting_test(&pm.this);
+#        ifdef PNG_READ_SUPPORTED
+            perform_standard_test(&pm);
+#        endif
+         perform_error_test(&pm);
+      }
+
+      /* Various oddly sized images: */
+      if (pm.test_size)
+      {
+         make_size_images(&pm.this);
+#        ifdef PNG_READ_SUPPORTED
+            perform_size_test(&pm);
+#        endif
+      }
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+      /* Combinatorial transforms: */
+      if (pm.test_transform)
+         perform_transform_test(&pm);
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+      if (pm.ngamma_tests > 0)
+         perform_gamma_test(&pm, summary);
+#endif
+   }
+
+   Catch_anonymous
+   {
+      fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
+      if (!pm.this.verbose)
+      {
+         if (pm.this.error[0] != 0)
+            fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
+
+         fprintf(stderr, "pngvalid: run with -v to see what happened\n");
+      }
+      exit(1);
+   }
+
+   if (summary)
+   {
+      printf("%s: %s (%s point arithmetic)\n",
+         (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
+            pm.this.nwarnings)) ? "FAIL" : "PASS",
+         command,
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
+         "floating"
+#else
+         "fixed"
+#endif
+         );
+   }
+
+   if (memstats)
+   {
+      printf("Allocated memory statistics (in bytes):\n"
+         "\tread  %lu maximum single, %lu peak, %lu total\n"
+         "\twrite %lu maximum single, %lu peak, %lu total\n",
+         (unsigned long)pm.this.read_memory_pool.max_max,
+         (unsigned long)pm.this.read_memory_pool.max_limit,
+         (unsigned long)pm.this.read_memory_pool.max_total,
+         (unsigned long)pm.this.write_memory_pool.max_max,
+         (unsigned long)pm.this.write_memory_pool.max_limit,
+         (unsigned long)pm.this.write_memory_pool.max_total);
+   }
+
+   /* Do this here to provoke memory corruption errors in memory not directly
+    * allocated by libpng - not a complete test, but better than nothing.
+    */
+   store_delete(&pm.this);
+
+   /* Error exit if there are any errors, and maybe if there are any
+    * warnings.
+    */
+   if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
+       pm.this.nwarnings))
+   {
+      if (!pm.this.verbose)
+         fprintf(stderr, "pngvalid: %s\n", pm.this.error);
+
+      fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
+          pm.this.nwarnings);
+
+      exit(1);
+   }
+
+   /* Success case. */
+   if (touch != NULL)
+   {
+      FILE *fsuccess = fopen(touch, "wt");
+
+      if (fsuccess != NULL)
+      {
+         int error = 0;
+         fprintf(fsuccess, "PNG validation succeeded\n");
+         fflush(fsuccess);
+         error = ferror(fsuccess);
+
+         if (fclose(fsuccess) || error)
+         {
+            fprintf(stderr, "%s: write failed\n", touch);
+            exit(1);
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "%s: open failed\n", touch);
+         exit(1);
+      }
+   }
+
+   /* This is required because some very minimal configurations do not use it:
+    */
+   UNUSED(fail)
+   return 0;
+}
+#else /* write or low level APIs not supported */
+int main(void)
+{
+   fprintf(stderr,
+      "pngvalid: no low level write support in libpng, all tests skipped\n");
+   /* So the test is skipped: */
+   return SKIP;
+}
+#endif
diff --git a/extern/libpng/contrib/libtests/readpng.c b/extern/libpng/contrib/libtests/readpng.c
new file mode 100644
index 0000000000..60a2d46c56
--- /dev/null
+++ b/extern/libpng/contrib/libtests/readpng.c
@@ -0,0 +1,115 @@
+/* readpng.c
+ *
+ * Copyright (c) 2013 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.1 [March 28, 2013]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Load an arbitrary number of PNG files (from the command line, or, if there
+ * are no arguments on the command line, from stdin) then run a time test by
+ * reading each file by row.  The test does nothing with the read result and
+ * does no transforms.  The only output is a time as a floating point number of
+ * seconds with 9 decimal digits.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+static int
+read_png(FILE *fp)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
+   png_infop info_ptr = NULL;
+   png_bytep row = NULL, display = NULL;
+
+   if (png_ptr == NULL)
+      return 0;
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      if (row != NULL) free(row);
+      if (display != NULL) free(display);
+      return 0;
+   }
+
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, NULL, 0);
+
+   png_read_info(png_ptr, info_ptr);
+
+   {
+      size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+      /* Failure to initialize these is harmless */
+      row = malloc(rowbytes);
+      display = malloc(rowbytes);
+
+      if (row == NULL || display == NULL)
+         png_error(png_ptr, "OOM allocating row buffers");
+
+      {
+         png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
+#        ifdef PNG_READ_INTERLACING_SUPPORTED
+            int passes = png_set_interlace_handling(png_ptr);
+#        else /* !READ_INTERLACING */
+            int passes = png_get_interlace_type(png_ptr, info_ptr) ==
+               PNG_INTERLACE_ADAM7 ? PNG_INTERLACE_ADAM7_PASSES : 1;
+#        endif /* !READ_INTERLACING */
+         int pass;
+
+         png_start_read_image(png_ptr);
+
+         for (pass = 0; pass < passes; ++pass)
+         {
+            png_uint_32 y = height;
+
+#           ifndef PNG_READ_INTERLACING_SUPPORTED
+               if (passes == PNG_INTERLACE_ADAM7_PASSES)
+                  y = PNG_PASS_ROWS(y, pass);
+#           endif /* READ_INTERLACING */
+
+            /* NOTE: this trashes the row each time; interlace handling won't
+             * work, but this avoids memory thrashing for speed testing.
+             */
+            while (y-- > 0)
+               png_read_row(png_ptr, row, display);
+         }
+      }
+   }
+
+   /* Make sure to read to the end of the file: */
+   png_read_end(png_ptr, info_ptr);
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   free(row);
+   free(display);
+   return 1;
+}
+
+int
+main(void)
+{
+   /* Exit code 0 on success. */
+   return !read_png(stdin);
+}
diff --git a/extern/libpng/contrib/libtests/tarith.c b/extern/libpng/contrib/libtests/tarith.c
new file mode 100644
index 0000000000..c03f05a80b
--- /dev/null
+++ b/extern/libpng/contrib/libtests/tarith.c
@@ -0,0 +1,999 @@
+
+/* tarith.c
+ *
+ * Copyright (c) 2011-2013 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Test internal arithmetic functions of libpng.
+ *
+ * This code must be linked against a math library (-lm), but does not require
+ * libpng or zlib to work.  Because it includes the complete source of 'png.c'
+ * it tests the code with whatever compiler options are used to build it.
+ * Changing these options can substantially change the errors in the
+ * calculations that the compiler chooses!
+ */
+#define _POSIX_SOURCE 1
+#define _ISOC99_SOURCE 1
+
+/* Obtain a copy of the code to be tested (plus other things), disabling
+ * stuff that is not required.
+ */
+#include <math.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <assert.h>
+
+#include "../../pngpriv.h"
+
+#define png_error png_warning
+
+void png_warning(png_const_structrp png_ptr, png_const_charp msg)
+{
+   fprintf(stderr, "validation: %s\n", msg);
+}
+
+#define png_fixed_error png_fixed_warning
+
+void png_fixed_warning(png_const_structrp png_ptr, png_const_charp msg)
+{
+   fprintf(stderr, "overflow in: %s\n", msg);
+}
+
+#define png_set_error_fn(pp, ep, efp, wfp) ((void)0)
+#define png_malloc(pp, s) malloc(s)
+#define png_malloc_warn(pp, s) malloc(s)
+#define png_malloc_base(pp, s) malloc(s)
+#define png_calloc(pp, s) calloc(1, (s))
+#define png_free(pp, s) free(s)
+
+#define png_safecat(b, sb, pos, str) (pos)
+#define png_format_number(start, end, format, number) (start)
+
+#define crc32(crc, pp, s) (crc)
+#define inflateReset(zs) Z_OK
+
+#define png_create_struct(type) (0)
+#define png_destroy_struct(pp) ((void)0)
+#define png_create_struct_2(type, m, mm) (0)
+#define png_destroy_struct_2(pp, f, mm) ((void)0)
+
+#undef PNG_SIMPLIFIED_READ_SUPPORTED
+#undef PNG_SIMPLIFIED_WRITE_SUPPORTED
+#undef PNG_USER_MEM_SUPPORTED
+
+#include "../../png.c"
+
+/* Validate ASCII to fp routines. */
+static int verbose = 0;
+
+int validation_ascii_to_fp(int count, int argc, char **argv)
+{
+   int    showall = 0;
+   double max_error=2;      /* As a percentage error-in-last-digit/.5 */
+   double max_error_abs=17; /* Used when precision is DBL_DIG */
+   double max = 0;
+   double max_abs = 0;
+   double test = 0; /* Important to test this. */
+   int    precision = 5;
+   int    nonfinite = 0;
+   int    finite = 0;
+   int    ok = 0;
+   int    failcount = 0;
+   int    minorarith = 0;
+
+   while (--argc > 0)
+      if (strcmp(*++argv, "-a") == 0)
+         showall = 1;
+      else if (strcmp(*argv, "-e") == 0 && argc > 0)
+      {
+         --argc;
+         max_error = atof(*++argv);
+      }
+      else if (strcmp(*argv, "-E") == 0 && argc > 0)
+      {
+         --argc;
+         max_error_abs = atof(*++argv);
+      }
+      else
+      {
+         fprintf(stderr, "unknown argument %s\n", *argv);
+         return 1;
+      }
+
+   do
+   {
+      size_t index;
+      int state, failed = 0;
+      char buffer[64];
+
+      if (isfinite(test))
+         ++finite;
+      else
+         ++nonfinite;
+
+      if (verbose)
+         fprintf(stderr, "%.*g %d\n", DBL_DIG, test, precision);
+
+      /* Check for overflow in the buffer by setting a marker. */
+      memset(buffer, 71, sizeof buffer);
+
+      png_ascii_from_fp(0, buffer, precision+10, test, precision);
+
+      /* Allow for a three digit exponent, this stuff will fail if
+       * the exponent is bigger than this!
+       */
+      if (buffer[precision+7] != 71)
+      {
+         fprintf(stderr, "%g[%d] -> '%s'[%lu] buffer overflow\n", test,
+            precision, buffer, (unsigned long)strlen(buffer));
+         failed = 1;
+      }
+
+      /* Following are used for the number parser below and must be
+       * initialized to zero.
+       */
+      state = 0;
+      index = 0;
+      if (!isfinite(test))
+      {
+         /* Expect 'inf' */
+         if (test >= 0 && strcmp(buffer, "inf") ||
+             test <  0 && strcmp(buffer, "-inf"))
+         {
+            fprintf(stderr, "%g[%d] -> '%s' but expected 'inf'\n", test,
+               precision, buffer);
+            failed = 1;
+         }
+      }
+      else if (!png_check_fp_number(buffer, precision+10, &state, &index) ||
+          buffer[index] != 0)
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but has bad format ('%c')\n", test,
+         precision, buffer, buffer[index]);
+         failed = 1;
+      }
+      else if (PNG_FP_IS_NEGATIVE(state) && !(test < 0))
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but negative value not so reported\n",
+            test, precision, buffer);
+         failed = 1;
+         assert(!PNG_FP_IS_ZERO(state));
+         assert(!PNG_FP_IS_POSITIVE(state));
+      }
+      else if (PNG_FP_IS_ZERO(state) && !(test == 0))
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but zero value not so reported\n",
+            test, precision, buffer);
+         failed = 1;
+         assert(!PNG_FP_IS_NEGATIVE(state));
+         assert(!PNG_FP_IS_POSITIVE(state));
+      }
+      else if (PNG_FP_IS_POSITIVE(state) && !(test > 0))
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but positive value not so reported\n",
+            test, precision, buffer);
+         failed = 1;
+         assert(!PNG_FP_IS_NEGATIVE(state));
+         assert(!PNG_FP_IS_ZERO(state));
+      }
+      else
+      {
+         /* Check the result against the original. */
+         double out = atof(buffer);
+         double change = fabs((out - test)/test);
+         double allow = .5/pow(10,
+            (precision >= DBL_DIG) ? DBL_DIG-1 : precision-1);
+
+         /* NOTE: if you hit this error case are you compiling with gcc
+          * and -O0?  Try -O2 - the errors can accumulate if the FP
+          * code above is not optimized and may drift outside the .5 in
+          * DBL_DIG allowed.  In any case a small number of errors may
+          * occur (very small ones - 1 or 2%) because of rounding in the
+          * calculations, either in the conversion API or in atof.
+          */
+         if (change >= allow && (isfinite(out) ||
+             fabs(test/DBL_MAX) <= 1-allow))
+         {
+            double percent = (precision >= DBL_DIG) ? max_error_abs : max_error;
+            double allowp = (change-allow)*100/allow;
+
+            if (precision >= DBL_DIG)
+            {
+               if (max_abs < allowp) max_abs = allowp;
+            }
+
+            else
+            {
+               if (max < allowp) max = allowp;
+            }
+
+            if (showall || allowp >= percent)
+            {
+               fprintf(stderr,
+                  "%.*g[%d] -> '%s' -> %.*g number changed (%g > %g (%d%%))\n",
+                  DBL_DIG, test, precision, buffer, DBL_DIG, out, change, allow,
+                  (int)round(allowp));
+               failed = 1;
+            }
+            else
+               ++minorarith;
+         }
+      }
+
+      if (failed)
+         ++failcount;
+      else
+         ++ok;
+
+skip:
+      /* Generate a new number and precision. */
+      precision = rand();
+      if (precision & 1) test = -test;
+      precision >>= 1;
+
+      /* Generate random numbers. */
+      if (test == 0 || !isfinite(test))
+         test = precision+1;
+      else
+      {
+         /* Derive the exponent from the previous rand() value. */
+         int exponent = precision % (DBL_MAX_EXP - DBL_MIN_EXP) + DBL_MIN_EXP;
+         int tmp;
+         test = frexp(test * rand(), &tmp);
+         test = ldexp(test, exponent);
+         precision >>= 8; /* arbitrary */
+      }
+
+      /* This limits the precision to 32 digits, enough for standard
+       * IEEE implementations which have at most 15 digits.
+       */
+      precision = (precision & 0x1f) + 1;
+   }
+   while (--count);
+
+   printf("Tested %d finite values, %d non-finite, %d OK (%d failed) %d minor "
+      "arithmetic errors\n", finite, nonfinite, ok, failcount, minorarith);
+   printf(" Error with >=%d digit precision %.2f%%\n", DBL_DIG, max_abs);
+   printf(" Error with < %d digit precision %.2f%%\n", DBL_DIG, max);
+
+   return 0;
+}
+
+/* Observe that valid FP numbers have the forms listed in the PNG extensions
+ * specification:
+ *
+ * [+,-]{integer,integer.fraction,.fraction}[{e,E}[+,-]integer]
+ *
+ * Test each of these in turn, including invalid cases.
+ */
+typedef enum checkfp_state
+{
+   start, fraction, exponent, states
+} checkfp_state;
+
+/* The characters (other than digits) that characterize the states: */
+static const char none[] = "";
+static const char hexdigits[16] = "0123456789ABCDEF";
+
+static const struct
+{
+   const char *start; /* Characters valid at the start */
+   const char *end;   /* Valid characters that end the state */
+   const char *tests; /* Characters to test after 2 digits seen */
+}
+state_characters[states] =
+{
+   /* start:    */ { "+-.", ".eE", "+-.e*0369" },
+   /* fraction: */ { none, "eE",  "+-.E#0147" },
+   /* exponent: */ { "+-", none,  "+-.eE^0258" }
+};
+
+typedef struct
+{
+   char number[1024];  /* Buffer for number being tested */
+   int  limit;         /* Command line limit */
+   int  verbose;       /* Shadows global variable */
+   int  ctimes;        /* Number of numbers tested */
+   int  cmillions;     /* Count of millions of numbers */
+   int  cinvalid;      /* Invalid strings checked */
+   int  cnoaccept;     /* Characters not accepted */
+}
+checkfp_command;
+
+typedef struct
+{
+   int           cnumber;          /* Index into number string */
+   checkfp_state check_state;      /* Current number state */
+   int           at_start;         /* At start (first character) of state */
+   int           cdigits_in_state; /* Digits seen in that state */
+   int           limit;            /* Limit on same for checking all chars */
+   int           state;            /* Current parser state */
+   int           is_negative;      /* Number is negative */
+   int           is_zero;          /* Number is (still) zero */
+   int           number_was_valid; /* Previous character validity */
+}
+checkfp_control;
+
+static int check_all_characters(checkfp_command *co, checkfp_control c);
+
+static int check_some_characters(checkfp_command *co, checkfp_control c,
+   const char *tests);
+
+static int check_one_character(checkfp_command *co, checkfp_control c, int ch)
+{
+   /* Test this character (ch) to ensure the parser does the correct thing.
+    */
+   size_t index = 0;
+   const char test = (char)ch;
+   int number_is_valid = png_check_fp_number(&test, 1, &c.state, &index);
+   int character_accepted = (index == 1);
+
+   if (c.check_state != exponent && isdigit(ch) && ch != '0')
+      c.is_zero = 0;
+
+   if (c.check_state == start && c.at_start && ch == '-')
+      c.is_negative = 1;
+
+   if (isprint(ch))
+      co->number[c.cnumber++] = (char)ch;
+   else
+   {
+      co->number[c.cnumber++] = '<';
+      co->number[c.cnumber++] = hexdigits[(ch >> 4) & 0xf];
+      co->number[c.cnumber++] = hexdigits[ch & 0xf];
+      co->number[c.cnumber++] = '>';
+   }
+   co->number[c.cnumber] = 0;
+
+   if (co->verbose > 1)
+      fprintf(stderr, "%s\n", co->number);
+
+   if (++(co->ctimes) == 1000000)
+   {
+      if (co->verbose == 1)
+         fputc('.', stderr);
+      co->ctimes = 0;
+      ++(co->cmillions);
+   }
+
+   if (!number_is_valid)
+      ++(co->cinvalid);
+
+   if (!character_accepted)
+      ++(co->cnoaccept);
+
+   /* This should never fail (it's a serious bug if it does): */
+   if (index != 0 && index != 1)
+   {
+      fprintf(stderr, "%s: read beyond end of string (%lu)\n", co->number,
+         (unsigned long)index);
+      return 0;
+   }
+
+   /* Validate the new state, note that the PNG_FP_IS_ macros all return
+    * false unless the number is valid.
+    */
+   if (PNG_FP_IS_NEGATIVE(c.state) !=
+      (number_is_valid && !c.is_zero && c.is_negative))
+   {
+      fprintf(stderr, "%s: negative when it is not\n", co->number);
+      return 0;
+   }
+
+   if (PNG_FP_IS_ZERO(c.state) != (number_is_valid && c.is_zero))
+   {
+      fprintf(stderr, "%s: zero when it is not\n", co->number);
+      return 0;
+   }
+
+   if (PNG_FP_IS_POSITIVE(c.state) !=
+      (number_is_valid && !c.is_zero && !c.is_negative))
+   {
+      fprintf(stderr, "%s: positive when it is not\n", co->number);
+      return 0;
+   }
+
+   /* Testing a digit */
+   if (isdigit(ch))
+   {
+      if (!character_accepted)
+      {
+         fprintf(stderr, "%s: digit '%c' not accepted\n", co->number, ch);
+         return 0;
+      }
+
+      if (!number_is_valid)
+      {
+         fprintf(stderr, "%s: saw a digit (%c) but number not valid\n",
+            co->number, ch);
+         return 0;
+      }
+
+      ++c.cdigits_in_state;
+      c.at_start = 0;
+      c.number_was_valid = 1;
+
+      /* Continue testing characters in this state.  Either test all of
+       * them or, if we have already seen one digit in this state, just test a
+       * limited set.
+       */
+      if (c.cdigits_in_state < 1)
+         return check_all_characters(co, c);
+
+      else
+         return check_some_characters(co, c,
+            state_characters[c.check_state].tests);
+   }
+
+   /* A non-digit; is it allowed here? */
+   else if (((ch == '+' || ch == '-') && c.check_state != fraction &&
+               c.at_start) ||
+            (ch == '.' && c.check_state == start) ||
+            ((ch == 'e' || ch == 'E') && c.number_was_valid &&
+               c.check_state != exponent))
+   {
+      if (!character_accepted)
+      {
+         fprintf(stderr, "%s: character '%c' not accepted\n", co->number, ch);
+         return 0;
+      }
+
+      /* The number remains valid after start of fraction but nowhere else. */
+      if (number_is_valid && (c.check_state != start || ch != '.'))
+      {
+         fprintf(stderr, "%s: saw a non-digit (%c) but number valid\n",
+            co->number, ch);
+         return 0;
+      }
+
+      c.number_was_valid = number_is_valid;
+
+      /* Check for a state change.  When changing to 'fraction' if the number
+       * is valid at this point set the at_start to false to allow an exponent
+       * 'e' to come next.
+       */
+      if (c.check_state == start && ch == '.')
+      {
+         c.check_state = fraction;
+         c.at_start = !number_is_valid;
+         c.cdigits_in_state = 0;
+         c.limit = co->limit;
+         return check_all_characters(co, c);
+      }
+
+      else if (c.check_state < exponent && (ch == 'e' || ch == 'E'))
+      {
+         c.check_state = exponent;
+         c.at_start = 1;
+         c.cdigits_in_state = 0;
+         c.limit = co->limit;
+         return check_all_characters(co, c);
+      }
+
+      /* Else it was a sign, and the state doesn't change. */
+      else
+      {
+         if (ch != '-' && ch != '+')
+         {
+            fprintf(stderr, "checkfp: internal error (1)\n");
+            return 0;
+         }
+
+         c.at_start = 0;
+         return check_all_characters(co, c);
+      }
+   }
+
+   /* Testing an invalid character */
+   else
+   {
+      if (character_accepted)
+      {
+         fprintf(stderr, "%s: character '%c' [0x%.2x] accepted\n", co->number,
+            ch, ch);
+         return 0;
+      }
+
+      if (number_is_valid != c.number_was_valid)
+      {
+         fprintf(stderr,
+            "%s: character '%c' [0x%.2x] changed number validity\n", co->number,
+            ch, ch);
+         return 0;
+      }
+
+      /* Do nothing - the parser has stuck; return success and keep going with
+       * the next character.
+       */
+   }
+
+   /* Successful return (the caller will try the next character.) */
+   return 1;
+}
+
+static int check_all_characters(checkfp_command *co, checkfp_control c)
+{
+   int ch;
+
+   if (c.cnumber+4 < sizeof co->number) for (ch=0; ch<256; ++ch)
+   {
+      if (!check_one_character(co, c, ch))
+         return 0;
+   }
+
+   return 1;
+}
+
+static int check_some_characters(checkfp_command *co, checkfp_control c,
+   const char *tests)
+{
+   int i;
+
+   --(c.limit);
+
+   if (c.cnumber+4 < sizeof co->number && c.limit >= 0)
+   {
+      if (c.limit > 0) for (i=0; tests[i]; ++i)
+      {
+         if (!check_one_character(co, c, tests[i]))
+               return 0;
+      }
+
+      /* At the end check all the characters. */
+      else
+         return check_all_characters(co, c);
+   }
+
+   return 1;
+}
+
+int validation_checkfp(int count, int argc, char **argv)
+{
+   int result;
+   checkfp_command command;
+   checkfp_control control;
+
+   command.number[0] = 0;
+   command.limit = 3;
+   command.verbose = verbose;
+   command.ctimes = 0;
+   command.cmillions = 0;
+   command.cinvalid = 0;
+   command.cnoaccept = 0;
+
+   while (--argc > 0)
+   {
+      ++argv;
+      if (argc > 1 && strcmp(*argv, "-l") == 0)
+      {
+         --argc;
+         command.limit = atoi(*++argv);
+      }
+
+      else
+      {
+         fprintf(stderr, "unknown argument %s\n", *argv);
+         return 1;
+      }
+   }
+
+   control.cnumber = 0;
+   control.check_state = start;
+   control.at_start = 1;
+   control.cdigits_in_state = 0;
+   control.limit = command.limit;
+   control.state = 0;
+   control.is_negative = 0;
+   control.is_zero = 1;
+   control.number_was_valid = 0;
+
+   result = check_all_characters(&command, control);
+
+   printf("checkfp: %s: checked %d,%.3d,%.3d,%.3d strings (%d invalid)\n",
+      result ? "pass" : "FAIL", command.cmillions / 1000,
+      command.cmillions % 1000, command.ctimes / 1000, command.ctimes % 1000,
+      command.cinvalid);
+
+   return result;
+}
+
+int validation_muldiv(int count, int argc, char **argv)
+{
+   int tested = 0;
+   int overflow = 0;
+   int error = 0;
+   int error64 = 0;
+   int passed = 0;
+   int randbits = 0;
+   png_uint_32 randbuffer;
+   png_fixed_point a;
+   png_int_32 times, div;
+
+   while (--argc > 0)
+      {
+         fprintf(stderr, "unknown argument %s\n", *++argv);
+         return 1;
+      }
+
+   /* Find out about the random number generator. */
+   randbuffer = RAND_MAX;
+   while (randbuffer != 0) ++randbits, randbuffer >>= 1;
+   printf("Using random number generator that makes %d bits\n", randbits);
+   for (div=0; div<32; div += randbits)
+      randbuffer = (randbuffer << randbits) ^ rand();
+
+   a = 0;
+   times = div = 0;
+   do
+   {
+      png_fixed_point result;
+      /* NOTE: your mileage may vary, a type is required below that can
+       * hold 64 bits or more, if floating point is used a 64-bit or
+       * better mantissa is required.
+       */
+      long long int fp, fpround;
+      unsigned long hi, lo;
+      int ok;
+
+      /* Check the values, png_64bit_product can only handle positive
+       * numbers, so correct for that here.
+       */
+      {
+         long u1, u2;
+         int n = 0;
+         if (a < 0) u1 = -a, n = 1; else u1 = a;
+         if (times < 0) u2 = -times, n = !n; else u2 = times;
+         png_64bit_product(u1, u2, &hi, &lo);
+         if (n)
+         {
+            /* -x = ~x+1 */
+            lo = ((~lo) + 1) & 0xffffffff;
+            hi = ~hi;
+            if (lo == 0) ++hi;
+         }
+      }
+
+      fp = a;
+      fp *= times;
+      if ((fp & 0xffffffff) != lo || ((fp >> 32) & 0xffffffff) != hi)
+      {
+         fprintf(stderr, "png_64bit_product %d * %d -> %lx|%.8lx not %llx\n",
+            a, times, hi, lo, fp);
+         ++error64;
+      }
+
+      if (div != 0)
+      {
+         /* Round - this is C round to zero. */
+         if ((fp < 0) != (div < 0))
+           fp -= div/2;
+         else
+           fp += div/2;
+
+         fp /= div;
+         fpround = fp;
+         /* Assume 2's complement here: */
+         ok = fpround <= PNG_UINT_31_MAX &&
+              fpround >= -1-(long long int)PNG_UINT_31_MAX;
+         if (!ok) ++overflow;
+      }
+      else
+        ok = 0, ++overflow, fpround = fp/*misleading*/;
+
+      if (verbose)
+         fprintf(stderr, "TEST %d * %d / %d -> %lld (%s)\n", a, times, div,
+            fp, ok ? "ok" : "overflow");
+
+      ++tested;
+      if (png_muldiv(&result, a, times, div) != ok)
+      {
+         ++error;
+         if (ok)
+             fprintf(stderr, "%d * %d / %d -> overflow (expected %lld)\n", a,
+                times, div, fp);
+         else
+             fprintf(stderr, "%d * %d / %d -> %d (expected overflow %lld)\n", a,
+                times, div, result, fp);
+      }
+      else if (ok && result != fpround)
+      {
+         ++error;
+         fprintf(stderr, "%d * %d / %d -> %d not %lld\n", a, times, div, result,
+            fp);
+      }
+      else
+         ++passed;
+
+      /* Generate three new values, this uses rand() and rand() only returns
+       * up to RAND_MAX.
+       */
+      /* CRUDE */
+      a += times;
+      times += div;
+      div = randbuffer;
+      randbuffer = (randbuffer << randbits) ^ rand();
+   }
+   while (--count > 0);
+
+   printf("%d tests including %d overflows, %d passed, %d failed (%d 64-bit "
+      "errors)\n", tested, overflow, passed, error, error64);
+   return 0;
+}
+
+/* When FP is on this just becomes a speed test - compile without FP to get real
+ * validation.
+ */
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+#define LN2 .000010576586617430806112933839 /* log(2)/65536 */
+#define L2INV 94548.46219969910586572651    /* 65536/log(2) */
+
+/* For speed testing, need the internal functions too: */
+static png_uint_32 png_log8bit(unsigned x)
+{
+   if (x > 0)
+      return (png_uint_32)floor(.5-log(x/255.)*L2INV);
+
+   return 0xffffffff;
+}
+
+static png_uint_32 png_log16bit(png_uint_32 x)
+{
+   if (x > 0)
+      return (png_uint_32)floor(.5-log(x/65535.)*L2INV);
+
+   return 0xffffffff;
+}
+
+static png_uint_32 png_exp(png_uint_32 x)
+{
+   return (png_uint_32)floor(.5 + exp(x * -LN2) * 0xffffffffU);
+}
+
+static png_byte png_exp8bit(png_uint_32 log)
+{
+   return (png_byte)floor(.5 + exp(log * -LN2) * 255);
+}
+
+static png_uint_16 png_exp16bit(png_uint_32 log)
+{
+   return (png_uint_16)floor(.5 + exp(log * -LN2) * 65535);
+}
+#endif /* FLOATING_ARITHMETIC */
+
+int validation_gamma(int argc, char **argv)
+{
+   double gamma[9] = { 2.2, 1.8, 1.52, 1.45, 1., 1/1.45, 1/1.52, 1/1.8, 1/2.2 };
+   double maxerr;
+   int i, silent=0, onlygamma=0;
+
+   /* Silence the output with -s, just test the gamma functions with -g: */
+   while (--argc > 0)
+      if (strcmp(*++argv, "-s") == 0)
+         silent = 1;
+      else if (strcmp(*argv, "-g") == 0)
+         onlygamma = 1;
+      else
+      {
+         fprintf(stderr, "unknown argument %s\n", *argv);
+         return 1;
+      }
+
+   if (!onlygamma)
+   {
+      /* First validate the log functions: */
+      maxerr = 0;
+      for (i=0; i<256; ++i)
+      {
+         double correct = -log(i/255.)/log(2.)*65536;
+         double error = png_log8bit(i) - correct;
+
+         if (i != 0 && fabs(error) > maxerr)
+            maxerr = fabs(error);
+
+         if (i == 0 && png_log8bit(i) != 0xffffffff ||
+             i != 0 && png_log8bit(i) != floor(correct+.5))
+         {
+            fprintf(stderr, "8-bit log error: %d: got %u, expected %f\n",
+               i, png_log8bit(i), correct);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 8-bit log error = %f\n", maxerr);
+
+      maxerr = 0;
+      for (i=0; i<65536; ++i)
+      {
+         double correct = -log(i/65535.)/log(2.)*65536;
+         double error = png_log16bit(i) - correct;
+
+         if (i != 0 && fabs(error) > maxerr)
+            maxerr = fabs(error);
+
+         if (i == 0 && png_log16bit(i) != 0xffffffff ||
+             i != 0 && png_log16bit(i) != floor(correct+.5))
+         {
+            if (error > .68) /* By experiment error is less than .68 */
+            {
+               fprintf(stderr, "16-bit log error: %d: got %u, expected %f"
+                  " error: %f\n", i, png_log16bit(i), correct, error);
+            }
+         }
+      }
+
+      if (!silent)
+         printf("maximum 16-bit log error = %f\n", maxerr);
+
+      /* Now exponentiations. */
+      maxerr = 0;
+      for (i=0; i<=0xfffff; ++i)
+      {
+         double correct = exp(-i/65536. * log(2.)) * (65536. * 65536);
+         double error = png_exp(i) - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > 1883) /* By experiment. */
+         {
+            fprintf(stderr, "32-bit exp error: %d: got %u, expected %f"
+                  " error: %f\n", i, png_exp(i), correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 32-bit exp error = %f\n", maxerr);
+
+      maxerr = 0;
+      for (i=0; i<=0xfffff; ++i)
+      {
+         double correct = exp(-i/65536. * log(2.)) * 255;
+         double error = png_exp8bit(i) - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > .50002) /* By experiment */
+         {
+            fprintf(stderr, "8-bit exp error: %d: got %u, expected %f"
+                  " error: %f\n", i, png_exp8bit(i), correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 8-bit exp error = %f\n", maxerr);
+
+      maxerr = 0;
+      for (i=0; i<=0xfffff; ++i)
+      {
+         double correct = exp(-i/65536. * log(2.)) * 65535;
+         double error = png_exp16bit(i) - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > .524) /* By experiment */
+         {
+            fprintf(stderr, "16-bit exp error: %d: got %u, expected %f"
+                  " error: %f\n", i, png_exp16bit(i), correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 16-bit exp error = %f\n", maxerr);
+   } /* !onlygamma */
+
+   /* Test the overall gamma correction. */
+   for (i=0; i<9; ++i)
+   {
+      unsigned j;
+      double g = gamma[i];
+      png_fixed_point gfp = floor(g * PNG_FP_1 + .5);
+
+      if (!silent)
+         printf("Test gamma %f\n", g);
+
+      maxerr = 0;
+      for (j=0; j<256; ++j)
+      {
+         double correct = pow(j/255., g) * 255;
+         png_byte out = png_gamma_8bit_correct(j, gfp);
+         double error = out - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (out != floor(correct+.5))
+         {
+            fprintf(stderr, "8bit %d ^ %f: got %d expected %f error %f\n",
+               j, g, out, correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("gamma %f: maximum 8-bit error %f\n", g, maxerr);
+
+      maxerr = 0;
+      for (j=0; j<65536; ++j)
+      {
+         double correct = pow(j/65535., g) * 65535;
+         png_uint_16 out = png_gamma_16bit_correct(j, gfp);
+         double error = out - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > 1.62)
+         {
+            fprintf(stderr, "16bit %d ^ %f: got %d expected %f error %f\n",
+               j, g, out, correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("gamma %f: maximum 16-bit error %f\n", g, maxerr);
+   }
+
+   return 0;
+}
+
+/**************************** VALIDATION TESTS ********************************/
+/* Various validation routines are included herein, they require some
+ * definition for png_warning and png_error, seetings of VALIDATION:
+ *
+ * 1: validates the ASCII to floating point conversions
+ * 2: validates png_muldiv
+ * 3: accuracy test of fixed point gamma tables
+ */
+
+/* The following COUNT (10^8) takes about 1 hour on a 1GHz Pentium IV
+ * processor.
+ */
+#define COUNT 1000000000
+
+int main(int argc, char **argv)
+{
+   int count = COUNT;
+
+   while (argc > 1)
+   {
+      if (argc > 2 && strcmp(argv[1], "-c") == 0)
+      {
+         count = atoi(argv[2]);
+         argc -= 2;
+         argv += 2;
+      }
+
+      else if (strcmp(argv[1], "-v") == 0)
+      {
+         ++verbose;
+         --argc;
+         ++argv;
+      }
+
+      else
+         break;
+   }
+
+   if (count > 0 && argc > 1)
+   {
+      if (strcmp(argv[1], "ascii") == 0)
+         return validation_ascii_to_fp(count, argc-1, argv+1);
+      else if (strcmp(argv[1], "checkfp") == 0)
+         return validation_checkfp(count, argc-1, argv+1);
+      else if (strcmp(argv[1], "muldiv") == 0)
+         return validation_muldiv(count, argc-1, argv+1);
+      else if (strcmp(argv[1], "gamma") == 0)
+         return validation_gamma(argc-1, argv+1);
+   }
+
+   /* Bad argument: */
+   fprintf(stderr,
+      "usage: tarith [-v] [-c count] {ascii,muldiv,gamma} [args]\n");
+   fprintf(stderr, " arguments: ascii [-a (all results)] [-e error%%]\n");
+   fprintf(stderr, "            checkfp [-l max-number-chars]\n");
+   fprintf(stderr, "            muldiv\n");
+   fprintf(stderr, "            gamma -s (silent) -g (only gamma; no log)\n");
+   return 1;
+}
diff --git a/extern/libpng/contrib/libtests/timepng.c b/extern/libpng/contrib/libtests/timepng.c
new file mode 100644
index 0000000000..23d8b17b13
--- /dev/null
+++ b/extern/libpng/contrib/libtests/timepng.c
@@ -0,0 +1,608 @@
+/* timepng.c
+ *
+ * Copyright (c) 2013,2016 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.22 [May 26, 2016]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Load an arbitrary number of PNG files (from the command line, or, if there
+ * are no arguments on the command line, from stdin) then run a time test by
+ * reading each file by row or by image (possibly with transforms in the latter
+ * case).  The only output is a time as a floating point number of seconds with
+ * 9 decimal digits.
+ */
+#define _POSIX_C_SOURCE 199309L /* for clock_gettime */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+
+#include <time.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+/* The following is to support direct compilation of this file as C++ */
+#ifdef __cplusplus
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+/* 'CLOCK_PROCESS_CPUTIME_ID' is one of the clock timers for clock_gettime.  It
+ * need not be supported even when clock_gettime is available.  It returns the
+ * 'CPU' time the process has consumed.  'CPU' time is assumed to include time
+ * when the CPU is actually blocked by a pending cache fill but not time
+ * waiting for page faults.  The attempt is to get a measure of the actual time
+ * the implementation takes to read a PNG ignoring the potentially very large IO
+ * overhead.
+ */
+#if defined (CLOCK_PROCESS_CPUTIME_ID) && defined(PNG_STDIO_SUPPORTED) &&\
+    defined(PNG_EASY_ACCESS_SUPPORTED) &&\
+    (PNG_LIBPNG_VER >= 10700 ? defined(PNG_READ_PNG_SUPPORTED) :\
+     defined (PNG_SEQUENTIAL_READ_SUPPORTED) &&\
+     defined(PNG_INFO_IMAGE_SUPPORTED))
+
+typedef struct
+{
+   FILE *input;
+   FILE *output;
+}  io_data;
+
+static PNG_CALLBACK(void, read_and_copy,
+      (png_structp png_ptr, png_bytep buffer, size_t cb))
+{
+   io_data *io = (io_data*)png_get_io_ptr(png_ptr);
+
+   if (fread(buffer, cb, 1, io->input) != 1)
+      png_error(png_ptr, strerror(errno));
+
+   if (fwrite(buffer, cb, 1, io->output) != 1)
+   {
+      perror("temporary file");
+      fprintf(stderr, "temporary file PNG write failed\n");
+      exit(1);
+   }
+}
+
+static void read_by_row(png_structp png_ptr, png_infop info_ptr,
+      FILE *write_ptr, FILE *read_ptr)
+{
+   /* These don't get freed on error, this is fine; the program immediately
+    * exits.
+    */
+   png_bytep row = NULL, display = NULL;
+   io_data io_copy;
+
+   if (write_ptr != NULL)
+   {
+      /* Set up for a copy to the temporary file: */
+      io_copy.input = read_ptr;
+      io_copy.output = write_ptr;
+      png_set_read_fn(png_ptr, &io_copy, read_and_copy);
+   }
+
+   png_read_info(png_ptr, info_ptr);
+
+   {
+      size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+      row = voidcast(png_bytep,malloc(rowbytes));
+      display = voidcast(png_bytep,malloc(rowbytes));
+
+      if (row == NULL || display == NULL)
+         png_error(png_ptr, "OOM allocating row buffers");
+
+      {
+         png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
+         int passes = png_set_interlace_handling(png_ptr);
+         int pass;
+
+         png_start_read_image(png_ptr);
+
+         for (pass = 0; pass < passes; ++pass)
+         {
+            png_uint_32 y = height;
+
+            /* NOTE: this trashes the row each time; interlace handling won't
+             * work, but this avoids memory thrashing for speed testing and is
+             * somewhat representative of an application that works row-by-row.
+             */
+            while (y-- > 0)
+               png_read_row(png_ptr, row, display);
+         }
+      }
+   }
+
+   /* Make sure to read to the end of the file: */
+   png_read_end(png_ptr, info_ptr);
+
+   /* Free this up: */
+   free(row);
+   free(display);
+}
+
+static PNG_CALLBACK(void, no_warnings, (png_structp png_ptr,
+         png_const_charp warning))
+{
+   (void)png_ptr;
+   (void)warning;
+}
+
+static int read_png(FILE *fp, png_int_32 transforms, FILE *write_file)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,
+         no_warnings);
+   png_infop info_ptr = NULL;
+
+   if (png_ptr == NULL)
+      return 0;
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      return 0;
+   }
+
+#  ifdef PNG_BENIGN_ERRORS_SUPPORTED
+      png_set_benign_errors(png_ptr, 1/*allowed*/);
+#  endif
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   if (transforms < 0)
+      read_by_row(png_ptr, info_ptr, write_file, fp);
+
+   else
+      png_read_png(png_ptr, info_ptr, transforms, NULL/*params*/);
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   return 1;
+}
+
+static int mytime(struct timespec *t)
+{
+   /* Do the timing using clock_gettime and the per-process timer. */
+   if (!clock_gettime(CLOCK_PROCESS_CPUTIME_ID, t))
+      return 1;
+
+   perror("CLOCK_PROCESS_CPUTIME_ID");
+   fprintf(stderr, "timepng: could not get the time\n");
+   return 0;
+}
+
+static int perform_one_test(FILE *fp, int nfiles, png_int_32 transforms)
+{
+   int i;
+   struct timespec before, after;
+
+   /* Clear out all errors: */
+   rewind(fp);
+
+   if (mytime(&before))
+   {
+      for (i=0; i<nfiles; ++i)
+      {
+         if (read_png(fp, transforms, NULL/*write*/))
+         {
+            if (ferror(fp))
+            {
+               perror("temporary file");
+               fprintf(stderr, "file %d: error reading PNG data\n", i);
+               return 0;
+            }
+         }
+
+         else
+         {
+            perror("temporary file");
+            fprintf(stderr, "file %d: error from libpng\n", i);
+            return 0;
+         }
+      }
+   }
+
+   else
+      return 0;
+
+   if (mytime(&after))
+   {
+      /* Work out the time difference and print it - this is the only output,
+       * so flush it immediately.
+       */
+      unsigned long s = after.tv_sec - before.tv_sec;
+      long ns = after.tv_nsec - before.tv_nsec;
+
+      if (ns < 0)
+      {
+         --s;
+         ns += 1000000000;
+
+         if (ns < 0)
+         {
+            fprintf(stderr, "timepng: bad clock from kernel\n");
+            return 0;
+         }
+      }
+
+      printf("%lu.%.9ld\n", s, ns);
+      fflush(stdout);
+      if (ferror(stdout))
+      {
+         fprintf(stderr, "timepng: error writing output\n");
+         return 0;
+      }
+
+      /* Successful return */
+      return 1;
+   }
+
+   else
+      return 0;
+}
+
+static int add_one_file(FILE *fp, char *name)
+{
+   FILE *ip = fopen(name, "rb");
+
+   if (ip != NULL)
+   {
+      /* Read the file using libpng; this detects errors and also deals with
+       * files which contain data beyond the end of the file.
+       */
+      int ok = 0;
+      fpos_t pos;
+
+      if (fgetpos(fp, &pos))
+      {
+         /* Fatal error reading the start: */
+         perror("temporary file");
+         fprintf(stderr, "temporary file fgetpos error\n");
+         exit(1);
+      }
+
+      if (read_png(ip, -1/*by row*/, fp/*output*/))
+      {
+         if (ferror(ip))
+         {
+            perror(name);
+            fprintf(stderr, "%s: read error\n", name);
+         }
+
+         else
+            ok = 1; /* read ok */
+      }
+
+      else
+         fprintf(stderr, "%s: file not added\n", name);
+
+      (void)fclose(ip);
+
+      /* An error in the output is fatal; exit immediately: */
+      if (ferror(fp))
+      {
+         perror("temporary file");
+         fprintf(stderr, "temporary file write error\n");
+         exit(1);
+      }
+
+      if (ok)
+         return 1;
+
+      /* Did not read the file successfully, simply rewind the temporary
+       * file.  This must happen after the ferror check above to avoid clearing
+       * the error.
+       */
+      if (fsetpos(fp, &pos))
+      {
+         perror("temporary file");
+         fprintf(stderr, "temporary file fsetpos error\n");
+         exit(1);
+      }
+   }
+
+   else
+   {
+      /* file open error: */
+      perror(name);
+      fprintf(stderr, "%s: open failed\n", name);
+   }
+
+   return 0; /* file not added */
+}
+
+static void
+usage(FILE *fp)
+{
+   if (fp != NULL) fclose(fp);
+
+   fprintf(stderr,
+"Usage:\n"
+" timepng --assemble <assembly> {files}\n"
+"  Read the files into <assembly>, output the count.  Options are ignored.\n"
+" timepng --dissemble <assembly> <count> [options]\n"
+"  Time <count> files from <assembly>, additional files may not be given.\n"
+" Otherwise:\n"
+"  Read the files into a temporary file and time the decode\n"
+"Transforms:\n"
+"  --by-image: read by image with png_read_png\n"
+"  --<transform>: implies by-image, use PNG_TRANSFORM_<transform>\n"
+"  Otherwise: read by row using png_read_row (to a single row buffer)\n"
+   /* ISO C90 string length max 509 */);fprintf(stderr,
+"{files}:\n"
+"  PNG files to copy into the assembly and time.  Invalid files are skipped\n"
+"  with appropriate error messages.  If no files are given the list of files\n"
+"  is read from stdin with each file name terminated by a newline\n"
+"Output:\n"
+"  For --assemble the output is the name of the assembly file followed by the\n"
+"  count of the files it contains; the arguments for --dissemble.  Otherwise\n"
+"  the output is the total decode time in seconds.\n");
+
+   exit(99);
+}
+
+int main(int argc, char **argv)
+{
+   int ok = 0;
+   int err = 0;
+   int nfiles = 0;
+   int transforms = -1; /* by row */
+   const char *assembly = NULL;
+   FILE *fp;
+
+   if (argc > 2 && strcmp(argv[1], "--assemble") == 0)
+   {
+      /* Just build the test file, argv[2] is the file name. */
+      assembly = argv[2];
+      fp = fopen(assembly, "wb");
+      if (fp == NULL)
+      {
+         perror(assembly);
+         fprintf(stderr, "timepng --assemble %s: could not open for write\n",
+               assembly);
+         usage(NULL);
+      }
+
+      argv += 2;
+      argc -= 2;
+   }
+
+   else if (argc > 3 && strcmp(argv[1], "--dissemble") == 0)
+   {
+      fp = fopen(argv[2], "rb");
+
+      if (fp == NULL)
+      {
+         perror(argv[2]);
+         fprintf(stderr, "timepng --dissemble %s: could not open for read\n",
+               argv[2]);
+         usage(NULL);
+      }
+
+      nfiles = atoi(argv[3]);
+      if (nfiles <= 0)
+      {
+         fprintf(stderr,
+               "timepng --dissemble <file> <count>: %s is not a count\n",
+               argv[3]);
+         exit(99);
+      }
+#ifdef __COVERITY__
+      else
+      {
+         nfiles &= PNG_UINT_31_MAX;
+      }
+#endif
+
+      argv += 3;
+      argc -= 3;
+   }
+
+   else /* Else use a temporary file */
+   {
+#ifndef __COVERITY__
+      fp = tmpfile();
+#else
+      /* Experimental. Coverity says tmpfile() is insecure because it
+       * generates predictable names.
+       *
+       * It is possible to satisfy Coverity by using mkstemp(); however,
+       * any platform supporting mkstemp() undoubtedly has a secure tmpfile()
+       * implementation as well, and doesn't need the fix.  Note that
+       * the fix won't work on platforms that don't support mkstemp().
+       *
+       * https://www.securecoding.cert.org/confluence/display/c/
+       * FIO21-C.+Do+not+create+temporary+files+in+shared+directories
+       * says that most historic implementations of tmpfile() provide
+       * only a limited number of possible temporary file names
+       * (usually 26) before file names are recycled. That article also
+       * provides a secure solution that unfortunately depends upon mkstemp().
+       */
+      char tmpfile[] = "timepng-XXXXXX";
+      int filedes;
+      umask(0177);
+      filedes = mkstemp(tmpfile);
+      if (filedes < 0)
+        fp = NULL;
+      else
+      {
+        fp = fdopen(filedes,"w+");
+        /* Hide the filename immediately and ensure that the file does
+         * not exist after the program ends
+         */
+        (void) unlink(tmpfile);
+      }
+#endif
+
+      if (fp == NULL)
+      {
+         perror("tmpfile");
+         fprintf(stderr, "timepng: could not open the temporary file\n");
+         exit(1); /* not a user error */
+      }
+   }
+
+   /* Handle the transforms: */
+   while (argc > 1 && argv[1][0] == '-' && argv[1][1] == '-')
+   {
+      const char *opt = *++argv + 2;
+
+      --argc;
+
+      /* Transforms turn on the by-image processing and maybe set some
+       * transforms:
+       */
+      if (transforms == -1)
+         transforms = PNG_TRANSFORM_IDENTITY;
+
+      if (strcmp(opt, "by-image") == 0)
+      {
+         /* handled above */
+      }
+
+#        define OPT(name) else if (strcmp(opt, #name) == 0)\
+         transforms |= PNG_TRANSFORM_ ## name
+
+      OPT(STRIP_16);
+      OPT(STRIP_ALPHA);
+      OPT(PACKING);
+      OPT(PACKSWAP);
+      OPT(EXPAND);
+      OPT(INVERT_MONO);
+      OPT(SHIFT);
+      OPT(BGR);
+      OPT(SWAP_ALPHA);
+      OPT(SWAP_ENDIAN);
+      OPT(INVERT_ALPHA);
+      OPT(STRIP_FILLER);
+      OPT(STRIP_FILLER_BEFORE);
+      OPT(STRIP_FILLER_AFTER);
+      OPT(GRAY_TO_RGB);
+      OPT(EXPAND_16);
+      OPT(SCALE_16);
+
+      else
+      {
+         fprintf(stderr, "timepng %s: unrecognized transform\n", opt);
+         usage(fp);
+      }
+   }
+
+   /* Handle the files: */
+   if (argc > 1 && nfiles > 0)
+      usage(fp); /* Additional files not valid with --dissemble */
+
+   else if (argc > 1)
+   {
+      int i;
+
+      for (i=1; i<argc; ++i)
+      {
+         if (nfiles == INT_MAX)
+         {
+            fprintf(stderr, "%s: skipped, too many files\n", argv[i]);
+            break;
+         }
+
+         else if (add_one_file(fp, argv[i]))
+            ++nfiles;
+      }
+   }
+
+   else if (nfiles == 0) /* Read from stdin withoout --dissemble */
+   {
+      char filename[FILENAME_MAX+1];
+
+      while (fgets(filename, FILENAME_MAX+1, stdin))
+      {
+         size_t len = strlen(filename);
+
+         if (filename[len-1] == '\n')
+         {
+            filename[len-1] = 0;
+            if (nfiles == INT_MAX)
+            {
+               fprintf(stderr, "%s: skipped, too many files\n", filename);
+               break;
+            }
+
+            else if (add_one_file(fp, filename))
+               ++nfiles;
+         }
+
+         else
+         {
+            fprintf(stderr, "timepng: file name too long: ...%s\n",
+               filename+len-32);
+            err = 1;
+            break;
+         }
+      }
+
+      if (ferror(stdin))
+      {
+         fprintf(stderr, "timepng: stdin: read error\n");
+         err = 1;
+      }
+   }
+
+   /* Perform the test, or produce the --assemble output: */
+   if (!err)
+   {
+      if (nfiles > 0)
+      {
+         if (assembly != NULL)
+         {
+            if (fflush(fp) && !ferror(fp) && fclose(fp))
+            {
+               perror(assembly);
+               fprintf(stderr, "%s: close failed\n", assembly);
+            }
+
+            else
+            {
+               printf("%s %d\n", assembly, nfiles);
+               fflush(stdout);
+               ok = !ferror(stdout);
+            }
+         }
+
+         else
+         {
+            ok = perform_one_test(fp, nfiles, transforms);
+            (void)fclose(fp);
+         }
+      }
+
+      else
+         usage(fp);
+   }
+
+   else
+      (void)fclose(fp);
+
+   /* Exit code 0 on success. */
+   return ok == 0;
+}
+#else /* !sufficient support */
+int main(void) { return 77; }
+#endif /* !sufficient support */
diff --git a/extern/libpng/contrib/mips-msa/README b/extern/libpng/contrib/mips-msa/README
new file mode 100644
index 0000000000..10acc93646
--- /dev/null
+++ b/extern/libpng/contrib/mips-msa/README
@@ -0,0 +1,83 @@
+OPERATING SYSTEM SPECIFIC MIPS MSA DETECTION
+--------------------------------------------
+
+Detection of the ability to execute MIPS MSA on an MIPS processor requires
+operating system support.  (The information is not available in user mode.)
+
+HOW TO USE THIS
+---------------
+
+This directory contains C code fragments that can be included in mips/mips_init.c
+by setting the macro PNG_MIPS_MSA_FILE to the file name in "" or <> at build
+time.  This setting is not recorded in pnglibconf.h and can be changed simply by
+rebuilding mips/msa_init.o with the required macro definition.
+
+For any of this code to be used the MIPS MSA code must be enabled and run time
+checks must be supported.  I.e.:
+
+#if PNG_MIPS_MSA_OPT > 0
+#ifdef PNG_MIPS_MSA_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-mips-msa=check
+
+Apart from the basic Linux implementation in contrib/mips-msa/linux.c this code
+is unsupported.  That means that it is not even compiled on a regular basis and
+may be broken in any given minor release.
+
+FILE FORMAT
+-----------
+
+Each file documents its testing status as of the last time it was tested (which
+may have been a long time ago):
+
+STATUS: one of:
+   SUPPORTED: This indicates that the file is included in the regularly
+         performed test builds and bugs are fixed when discovered.
+   COMPILED: This indicates that the code did compile at least once.  See the
+         more detailed description for the extent to which the result was
+         successful.
+   TESTED: This means the code was fully compiled into the libpng test programs
+         and these were run at least once.
+
+BUG REPORTS: an email address to which to send reports of problems
+
+The file is a fragment of C code. It should not define any 'extern' symbols;
+everything should be static.  It must define the function:
+
+static int png_have_msa(png_structp png_ptr);
+
+That function must return 1 if MIPS MSA instructions are supported, 0 if not.
+It must not execute png_error unless it detects a bug.  A png_error will prevent
+the reading of the PNG and in the future, writing too.
+
+BUG REPORTS
+-----------
+
+If you mail a bug report for any file that is not SUPPORTED there may only be
+limited response.  Consider fixing it and sending a patch to fix the problem -
+this is more likely to result in action.
+
+CONTRIBUTIONS
+-------------
+
+You may send contributions of new implementations to
+png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+possible.  Obviously OS dependencies are to be expected.  If you submit code you
+must have the authors permission and it must have a license that is acceptable
+to the current maintainer; in particular that license must permit modification
+and redistribution.
+
+Please try to make the contribution a single file and give the file a clear and
+unambiguous name that identifies the target OS.  If multiple files really are
+required put them all in a sub-directory.
+
+You must also be prepared to handle bug reports from users of the code, either
+by joining the png-mng-implement mailing list or by providing an email for the
+"BUG REPORTS" entry or both.  Please make sure that the header of the file
+contains the STATUS and BUG REPORTS fields as above.
+
+Please list the OS requirements as precisely as possible.  Ideally you should
+also list the environment in which the code has been tested and certainly list
+any environments where you suspect it might not work.
diff --git a/extern/libpng/contrib/mips-msa/linux.c b/extern/libpng/contrib/mips-msa/linux.c
new file mode 100644
index 0000000000..140215c4ea
--- /dev/null
+++ b/extern/libpng/contrib/mips-msa/linux.c
@@ -0,0 +1,64 @@
+/* contrib/mips-msa/linux.c
+ *
+ * Copyright (c) 2016 Glenn Randers-Pehrson
+ * Written by Mandar Sahastrabuddhe, 2016.
+ * Last changed in libpng 1.6.25beta03 [August 29, 2016]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/mips-msa/README before reporting bugs
+ *
+ * STATUS: SUPPORTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_msa implemented for Linux by reading the widely available
+ * pseudo-file /proc/cpuinfo.
+ *
+ * This code is strict ANSI-C and is probably moderately portable; it does
+ * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+static int
+png_have_msa(png_structp png_ptr)
+{
+   FILE *f = fopen("/proc/cpuinfo", "rb");
+
+   char *string = "msa";
+   char word[10];
+
+   if (f != NULL)
+   {
+      while(!feof(f))
+      {
+         int ch = fgetc(f);
+         static int i = 0;
+
+         while(!(ch <= 32))
+         {
+            word[i++] = ch;
+            ch = fgetc(f);
+         }
+
+         int val = strcmp(string, word);
+
+         if (val == 0)
+            return 1;
+
+         i = 0;
+         memset(word, 0, 10);
+      }
+
+      fclose(f);
+   }
+#ifdef PNG_WARNINGS_SUPPORTED
+   else
+      png_warning(png_ptr, "/proc/cpuinfo open failed");
+#endif
+   return 0;
+}
diff --git a/extern/libpng/contrib/oss-fuzz/Dockerfile b/extern/libpng/contrib/oss-fuzz/Dockerfile
new file mode 100644
index 0000000000..f5bc1a985d
--- /dev/null
+++ b/extern/libpng/contrib/oss-fuzz/Dockerfile
@@ -0,0 +1,25 @@
+# Copyright 2016 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+################################################################################
+
+FROM gcr.io/oss-fuzz-base/base-builder
+MAINTAINER glennrp@gmail.com
+RUN apt-get update && \
+    apt-get install -y make autoconf automake libtool
+
+RUN git clone --depth 1 https://github.com/madler/zlib.git
+RUN git clone --depth 1 https://github.com/glennrp/libpng.git
+RUN cp libpng/contrib/oss-fuzz/build.sh $SRC
+WORKDIR libpng
diff --git a/extern/libpng/contrib/oss-fuzz/README.txt b/extern/libpng/contrib/oss-fuzz/README.txt
new file mode 100644
index 0000000000..3b3656fbb6
--- /dev/null
+++ b/extern/libpng/contrib/oss-fuzz/README.txt
@@ -0,0 +1,37 @@
+Last changed in libpng 1.6.33 [September 28, 2017]
+Copyright (c) 2017 Glenn Randers-Pehrson
+
+This code is released under the libpng license.
+For conditions of distribution and use, see the disclaimer
+and license in png.h
+
+Files in this directory are used by the oss-fuzz project
+(https://github.com/google/oss-fuzz/tree/master/projects/libpng).
+for "fuzzing" libpng.
+
+They were licensed by Google Inc, using the BSD-like Chromium license,
+which may be found at https://cs.chromium.org/chromium/src/LICENSE, or, if
+noted in the source, under the Apache-2.0 license, which may
+be found at http://www.apache.org/licenses/LICENSE-2.0 .
+If they have been modified, the derivatives are copyright Glenn Randers-Pehrson
+and are released under the same licenses as the originals.  Several of
+the original files (libpng_read_fuzzer.options, png.dict, project.yaml)
+had no licensing information; we assumed that these were under the Chromium
+license. Any new files are released under the libpng license (see png.h).
+
+The files are
+                            Original
+ Filename                   or derived   Copyright          License
+ =========================  ==========   ================   ==========
+ Dockerfile*                derived      2017, Glenn R-P    Apache 2.0
+ build.sh                   derived      2017, Glenn R-P    Apache 2.0
+ libpng_read_fuzzer.cc      derived      2017, Glenn R-P    Chromium
+ libpng_read_fuzzer.options original     2015, Chrome Devs  Chromium
+ png.dict                   original     2015, Chrome Devs  Chromium
+ README.txt (this file)     original     2017, Glenn R-P    libpng
+
+ * Dockerfile is a copy of the file used by oss-fuzz. build.sh,
+   png.dict and libpng_read_fuzzer.* are the actual files used by oss-fuzz,
+   which retrieves them from the libpng repository at Github.
+
+To do: exercise the progressive reader and the png encoder.
diff --git a/extern/libpng/contrib/oss-fuzz/build.sh b/extern/libpng/contrib/oss-fuzz/build.sh
new file mode 100755
index 0000000000..f9e1b0776d
--- /dev/null
+++ b/extern/libpng/contrib/oss-fuzz/build.sh
@@ -0,0 +1,51 @@
+#!/bin/bash -eu
+# Copyright 2017-2018 Glenn Randers-Pehrson
+# Copyright 2016 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Last changed in libpng 1.6.35 [July 15, 2018]
+#
+# Revisions by Glenn Randers-Pehrson, 2017:
+# 1. Build only the library, not the tools (changed "make -j$(nproc) all" to
+#     "make -j$(nproc) libpng16.la").
+# 2. Disabled WARNING and WRITE options in pnglibconf.dfa.
+# 3. Build zlib alongside libpng
+################################################################################
+
+# Disable logging via library build configuration control.
+cat scripts/pnglibconf.dfa | \
+  sed -e "s/option STDIO/option STDIO disabled/" \
+      -e "s/option WARNING /option WARNING disabled/" \
+      -e "s/option WRITE enables WRITE_INT_FUNCTIONS/option WRITE disabled/" \
+> scripts/pnglibconf.dfa.temp
+mv scripts/pnglibconf.dfa.temp scripts/pnglibconf.dfa
+
+# build the libpng library.
+autoreconf -f -i
+./configure --with-libpng-prefix=OSS_FUZZ_
+make -j$(nproc) clean
+make -j$(nproc) libpng16.la
+
+# build libpng_read_fuzzer.
+$CXX $CXXFLAGS -std=c++11 -I. \
+     $SRC/libpng/contrib/oss-fuzz/libpng_read_fuzzer.cc \
+     -o $OUT/libpng_read_fuzzer \
+     -lFuzzingEngine .libs/libpng16.a -lz
+
+# add seed corpus.
+find $SRC/libpng -name "*.png" | grep -v crashers | \
+     xargs zip $OUT/libpng_read_fuzzer_seed_corpus.zip
+
+cp $SRC/libpng/contrib/oss-fuzz/*.dict \
+     $SRC/libpng/contrib/oss-fuzz/*.options $OUT/
diff --git a/extern/libpng/contrib/oss-fuzz/libpng_read_fuzzer.cc b/extern/libpng/contrib/oss-fuzz/libpng_read_fuzzer.cc
new file mode 100644
index 0000000000..7b305509cd
--- /dev/null
+++ b/extern/libpng/contrib/oss-fuzz/libpng_read_fuzzer.cc
@@ -0,0 +1,190 @@
+
+// libpng_read_fuzzer.cc
+// Copyright 2017-2018 Glenn Randers-Pehrson
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that may
+// be found in the LICENSE file https://cs.chromium.org/chromium/src/LICENSE
+
+// Last changed in libpng 1.6.35 [July 15, 2018]
+
+// The modifications in 2017 by Glenn Randers-Pehrson include
+// 1. addition of a PNG_CLEANUP macro,
+// 2. setting the option to ignore ADLER32 checksums,
+// 3. adding "#include <string.h>" which is needed on some platforms
+//    to provide memcpy().
+// 4. adding read_end_info() and creating an end_info structure.
+// 5. adding calls to png_set_*() transforms commonly used by browsers.
+
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <vector>
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#define PNG_CLEANUP \
+  if(png_handler.png_ptr) \
+  { \
+    if (png_handler.row_ptr) \
+      png_free(png_handler.png_ptr, png_handler.row_ptr); \
+    if (png_handler.end_info_ptr) \
+      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
+        &png_handler.end_info_ptr); \
+    else if (png_handler.info_ptr) \
+      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
+        nullptr); \
+    else \
+      png_destroy_read_struct(&png_handler.png_ptr, nullptr, nullptr); \
+    png_handler.png_ptr = nullptr; \
+    png_handler.row_ptr = nullptr; \
+    png_handler.info_ptr = nullptr; \
+    png_handler.end_info_ptr = nullptr; \
+  }
+
+struct BufState {
+  const uint8_t* data;
+  size_t bytes_left;
+};
+
+struct PngObjectHandler {
+  png_infop info_ptr = nullptr;
+  png_structp png_ptr = nullptr;
+  png_infop end_info_ptr = nullptr;
+  png_voidp row_ptr = nullptr;
+  BufState* buf_state = nullptr;
+
+  ~PngObjectHandler() {
+    if (row_ptr)
+      png_free(png_ptr, row_ptr);
+    if (end_info_ptr)
+      png_destroy_read_struct(&png_ptr, &info_ptr, &end_info_ptr);
+    else if (info_ptr) 
+      png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
+    else
+      png_destroy_read_struct(&png_ptr, nullptr, nullptr);
+    delete buf_state;
+  }
+};
+
+void user_read_data(png_structp png_ptr, png_bytep data, size_t length) {
+  BufState* buf_state = static_cast<BufState*>(png_get_io_ptr(png_ptr));
+  if (length > buf_state->bytes_left) {
+    png_error(png_ptr, "read error");
+  }
+  memcpy(data, buf_state->data, length);
+  buf_state->bytes_left -= length;
+  buf_state->data += length;
+}
+
+static const int kPngHeaderSize = 8;
+
+// Entry point for LibFuzzer.
+// Roughly follows the libpng book example:
+// http://www.libpng.org/pub/png/book/chapter13.html
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size < kPngHeaderSize) {
+    return 0;
+  }
+
+  std::vector<unsigned char> v(data, data + size);
+  if (png_sig_cmp(v.data(), 0, kPngHeaderSize)) {
+    // not a PNG.
+    return 0;
+  }
+
+  PngObjectHandler png_handler;
+  png_handler.png_ptr = nullptr;
+  png_handler.row_ptr = nullptr;
+  png_handler.info_ptr = nullptr;
+  png_handler.end_info_ptr = nullptr;
+
+  png_handler.png_ptr = png_create_read_struct
+    (PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
+  if (!png_handler.png_ptr) {
+    return 0;
+  }
+
+  png_handler.info_ptr = png_create_info_struct(png_handler.png_ptr);
+  if (!png_handler.info_ptr) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  png_handler.end_info_ptr = png_create_info_struct(png_handler.png_ptr);
+  if (!png_handler.end_info_ptr) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  png_set_crc_action(png_handler.png_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
+#ifdef PNG_IGNORE_ADLER32
+  png_set_option(png_handler.png_ptr, PNG_IGNORE_ADLER32, PNG_OPTION_ON);
+#endif
+
+  // Setting up reading from buffer.
+  png_handler.buf_state = new BufState();
+  png_handler.buf_state->data = data + kPngHeaderSize;
+  png_handler.buf_state->bytes_left = size - kPngHeaderSize;
+  png_set_read_fn(png_handler.png_ptr, png_handler.buf_state, user_read_data);
+  png_set_sig_bytes(png_handler.png_ptr, kPngHeaderSize);
+
+  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // Reading.
+  png_read_info(png_handler.png_ptr, png_handler.info_ptr);
+
+  // reset error handler to put png_deleter into scope.
+  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  png_uint_32 width, height;
+  int bit_depth, color_type, interlace_type, compression_type;
+  int filter_type;
+
+  if (!png_get_IHDR(png_handler.png_ptr, png_handler.info_ptr, &width,
+                    &height, &bit_depth, &color_type, &interlace_type,
+                    &compression_type, &filter_type)) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // This is going to be too slow.
+  if (width && height > 100000000 / width) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // Set several transforms that browsers typically use:
+  png_set_gray_to_rgb(png_handler.png_ptr);
+  png_set_expand(png_handler.png_ptr);
+  png_set_packing(png_handler.png_ptr);
+  png_set_scale_16(png_handler.png_ptr);
+  png_set_tRNS_to_alpha(png_handler.png_ptr);
+
+  int passes = png_set_interlace_handling(png_handler.png_ptr);
+
+  png_read_update_info(png_handler.png_ptr, png_handler.info_ptr);
+
+  png_handler.row_ptr = png_malloc(
+      png_handler.png_ptr, png_get_rowbytes(png_handler.png_ptr,
+                                            png_handler.info_ptr));
+
+  for (int pass = 0; pass < passes; ++pass) {
+    for (png_uint_32 y = 0; y < height; ++y) {
+      png_read_row(png_handler.png_ptr,
+                   static_cast<png_bytep>(png_handler.row_ptr), nullptr);
+    }
+  }
+
+  png_read_end(png_handler.png_ptr, png_handler.end_info_ptr);
+
+  PNG_CLEANUP
+  return 0;
+}
diff --git a/extern/libpng/contrib/oss-fuzz/libpng_read_fuzzer.options b/extern/libpng/contrib/oss-fuzz/libpng_read_fuzzer.options
new file mode 100644
index 0000000000..2005291a0f
--- /dev/null
+++ b/extern/libpng/contrib/oss-fuzz/libpng_read_fuzzer.options
@@ -0,0 +1,2 @@
+[libfuzzer]
+dict = png.dict
diff --git a/extern/libpng/contrib/oss-fuzz/png.dict b/extern/libpng/contrib/oss-fuzz/png.dict
new file mode 100644
index 0000000000..3a8a113830
--- /dev/null
+++ b/extern/libpng/contrib/oss-fuzz/png.dict
@@ -0,0 +1,39 @@
+#
+# AFL dictionary for PNG images
+# -----------------------------
+#
+# Just the basic, standard-originating sections; does not include vendor
+# extensions.
+#
+# Created by Michal Zalewski <lcamtuf@google.com>
+#
+
+header_png="\x89PNG\x0d\x0a\x1a\x0a"
+
+section_IDAT="IDAT"
+section_IEND="IEND"
+section_IHDR="IHDR"
+section_PLTE="PLTE"
+section_bKGD="bKGD"
+section_cHRM="cHRM"
+section_eXIf="eXIf"
+section_fRAc="fRAc"
+section_gAMA="gAMA"
+section_gIFg="gIFg"
+section_gIFt="gIFt"
+section_gIFx="gIFx"
+section_hIST="hIST"
+section_iCCP="iCCP"
+section_iTXt="iTXt"
+section_oFFs="oFFs"
+section_pCAL="pCAL"
+section_pHYs="pHYs"
+section_sBIT="sBIT"
+section_sCAL="sCAL"
+section_sPLT="sPLT"
+section_sRGB="sRGB"
+section_sTER="sTER"
+section_tEXt="tEXt"
+section_tIME="tIME"
+section_tRNS="tRNS"
+section_zTXt="zTXt"
diff --git a/extern/libpng/contrib/pngminim/README b/extern/libpng/contrib/pngminim/README
new file mode 100644
index 0000000000..e17fe35b6a
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/README
@@ -0,0 +1,5 @@
+
+This demonstrates the use of PNG_USER_CONFIG, pngusr.h and pngusr.dfa
+to build minimal decoder, encoder, and progressive reader applications.
+
+See the individual README and pngusr.dfa files for more explanation.
diff --git a/extern/libpng/contrib/pngminim/decoder/README b/extern/libpng/contrib/pngminim/decoder/README
new file mode 100644
index 0000000000..fa979fcb72
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/decoder/README
@@ -0,0 +1,10 @@
+This demonstrates the use of PNG_USER_CONFIG, pngusr.h and pngusr.dfa
+
+The makefile builds a minimal read-only decoder with embedded libpng
+and zlib.
+
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
+
+If you prefer to use the shared libraries, go to contrib/pngminus
+and build the png2pnm application there.
diff --git a/extern/libpng/contrib/pngminim/decoder/makefile b/extern/libpng/contrib/pngminim/decoder/makefile
new file mode 100644
index 0000000000..4acf3c1779
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/decoder/makefile
@@ -0,0 +1,151 @@
+# Makefile for PngMinus (pngm2pnm)
+# Linux / Unix
+
+#CC=cc
+CC=gcc
+LD=$(CC)
+
+# If awk fails try
+# make AWK=nawk
+
+# If cpp fails try
+# make CPP=/lib/cpp
+
+RM=rm -f
+COPY=cp
+
+CPPFLAGS=-I. -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall
+
+C=.c
+O=.o
+L=.a
+E=
+
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/pngminus
+
+# Zlib (minimal inflate requirements - crc32 is used by libpng)
+# zutil can be eliminated if you provide your own zcalloc and zcfree
+ZSRCS  = adler32$(C) crc32$(C) \
+	 inffast$(C) inflate$(C) inftrees$(C) \
+	 zutil$(C)
+
+# Standard headers
+ZH     = zlib.h crc32.h inffast.h inffixed.h \
+	 inflate.h inftrees.h zutil.h
+
+# Machine generated headers
+ZCONF  = zconf.h
+
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+
+ZOBJS  = adler32$(O) crc32$(O) \
+	 inffast$(O) inflate$(O) inftrees$(O) \
+	 zutil$(O)
+
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+	pngread$(C) pngrio$(C) pngrtran$(C) pngrutil$(C) \
+	pngset$(C) pngtrans$(C)
+	
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+
+# Machine generated headers
+PNGCONF=pnglibconf.h
+
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+	pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) \
+	pngset$(O) pngtrans$(O)
+
+PROGSRCS= pngm2pnm$(C)
+PROGHDRS=
+PROGDOCS=
+PROGOBJS= pngm2pnm$(O)
+
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+
+# implicit make rules -------------------------------------------------------
+
+# note: dependencies do not work on implicit rule lines
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+# dependencies
+
+all: pngm2pnm$(E)
+
+pngm2pnm$(E): $(OBJS)
+	$(LD) -o pngm2pnm$(E) $(OBJS)
+
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
+	$(PNGSRC)/scripts/pnglibconf.dfa \
+	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+	$(RM) pnglibconf.h pnglibconf.dfn
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
+	    DFA_XTRA="pngusr.dfa" $@
+
+clean:
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) clean
+	$(RM) pngm2pnm$(O)
+	$(RM) pngm2pnm$(E)
+	$(RM) $(OBJS)
+
+# distclean also removes the copied source and headers
+distclean: clean
+	$(RM) -r scripts # historical reasons
+	$(RM) $(PNGSRCS) $(PNGH)
+	$(RM) $(ZSRCS) $(ZH) $(ZCONF)
+	$(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+	$(RM) $@
+	$(COPY) $(PNGSRC)/$@ $@
+
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+	$(RM) $@
+	$(COPY) $(ZLIBSRC)/$@ $@
+
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+	$(RM) $@
+	@for f in zconf.h.in zconf.in.h zconf.h; do\
+	    test -r $(ZLIBSRC)/$$f &&\
+	    echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+	    $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+	done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+
+pngm2pnm.c: $(PROGSRC)/png2pnm.c
+	$(RM) $@
+	$(COPY) $(PROGSRC)/png2pnm.c $@
+
+# End of makefile for pngm2pnm
diff --git a/extern/libpng/contrib/pngminim/decoder/pngusr.dfa b/extern/libpng/contrib/pngminim/decoder/pngusr.dfa
new file mode 100644
index 0000000000..4f402721ab
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/decoder/pngusr.dfa
@@ -0,0 +1,40 @@
+# pngminim/decoder/pngusr.dfa
+#
+# Copyright (c) 2010-2013 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# First all the build options off:
+
+everything = off
+
+# All that is required is some read code. This example switches
+# on the sequential read code (see ../preader for a progressive
+# read example).
+
+option SEQUENTIAL_READ on
+
+# You must choose fixed or floating point arithmetic:
+# option FLOATING_POINT on
+
+option FIXED_POINT on
+
+# You must chose the internal fixed point implementation or to
+# use the system floating point.  The latter is considerably
+# smaller (by about 1kbyte on an x86 system):
+# option FLOATING_ARITHMETIC on
+
+option FLOATING_ARITHMETIC off
+
+# Your program will probably need other options.  The example
+# program here, pngm2pnm, requires the following.  Take a look
+# at pnglibconf.h to find out the full set of what has to be
+# enabled to make the following work.
+
+option SETJMP on
+option STDIO on
+option READ_EXPAND on
+option READ_STRIP_16_TO_8 on
+option USER_LIMITS on
diff --git a/extern/libpng/contrib/pngminim/decoder/pngusr.h b/extern/libpng/contrib/pngminim/decoder/pngusr.h
new file mode 100644
index 0000000000..cbd7890c7d
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/decoder/pngusr.h
@@ -0,0 +1,23 @@
+/* minrdpngconf.h: headers to make a minimal png-read-only library
+ *
+ * Copyright (c) 2007, 2010-2013 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
+ */
+
+#ifndef MINRDPNGCONF_H
+#define MINRDPNGCONF_H
+
+/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
+
+/* List options to turn off features of the build that do not
+ * affect the API (so are not recorded in pnglibconf.h)
+ */
+
+#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
+
+#endif /* MINRDPNGCONF_H */
diff --git a/extern/libpng/contrib/pngminim/encoder/README b/extern/libpng/contrib/pngminim/encoder/README
new file mode 100644
index 0000000000..d8d9a6466e
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/encoder/README
@@ -0,0 +1,10 @@
+This demonstrates the use of PNG_USER_CONFIG and pngusr.h
+
+The makefile builds a minimal write-only encoder with embedded libpng
+and zlib.
+
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
+
+If you prefer to use the shared libraries, go to contrib/pngminus
+and build the pnm2png application there.
diff --git a/extern/libpng/contrib/pngminim/encoder/makefile b/extern/libpng/contrib/pngminim/encoder/makefile
new file mode 100644
index 0000000000..41b205c284
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/encoder/makefile
@@ -0,0 +1,150 @@
+# Makefile for PngMinus (pnm2pngm)
+# Linux / Unix
+
+#CC=cc
+CC=gcc
+LD=$(CC)
+
+# If awk fails try
+# make AWK=nawk
+
+# If cpp fails try
+# make CPP=/lib/cpp
+
+RM=rm -f
+COPY=cp
+
+CPPFLAGS=-I. -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall
+
+C=.c
+O=.o
+L=.a
+E=
+
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/pngminus
+
+# Zlib
+ZSRCS  = adler32$(C) compress$(C) crc32$(C) deflate$(C) \
+	 trees$(C) zutil$(C)
+
+# Standard headers
+#ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
+ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
+
+# Machine generated headers
+ZCONF  = zconf.h
+
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+
+# compress is not required; it is needed to link the zlib
+# code because deflate defines an unused API function deflateBound
+# which itself calls compressBound from compress.
+ZOBJS  = adler32$(O) compress$(O) crc32$(O) deflate$(O) \
+	 trees$(O) zutil$(O)
+
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+	pngset$(C) pngtrans$(C) pngwio$(C) pngwrite$(C) \
+	pngwtran$(C) pngwutil$(C)
+
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+
+# Machine generated headers
+PNGCONF=pnglibconf.h
+
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+	pngset$(O) pngtrans$(O) pngwio$(O) pngwrite$(O) \
+	pngwtran$(O) pngwutil$(O)
+
+PROGSRCS= pnm2pngm$(C)
+PROGHDRS=
+PROGDOCS=
+PROGOBJS= pnm2pngm$(O)
+
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+# dependencies
+
+all: pnm2pngm$(E)
+
+pnm2pngm$(E): $(OBJS)
+	$(LD) -o pnm2pngm$(E) $(OBJS)
+
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
+	$(PNGSRC)/scripts/pnglibconf.dfa \
+	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+	$(RM) pnglibconf.h pnglibconf.dfn
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
+	    DFA_XTRA="pngusr.dfa" $@
+
+clean:
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) clean
+	$(RM) pnm2pngm$(O)
+	$(RM) pnm2pngm$(E)
+	$(RM) $(OBJS)
+
+# distclean also removes the copied source and headers
+distclean: clean
+	$(RM) -r scripts # historical reasons
+	$(RM) $(PNGSRCS) $(PNGH)
+	$(RM) $(ZSRCS) $(ZH) $(ZCONF)
+	$(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+	$(RM) $@
+	$(COPY) $(PNGSRC)/$@ $@
+
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+	$(RM) $@
+	$(COPY) $(ZLIBSRC)/$@ $@
+
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+	$(RM) $@
+	@for f in zconf.h.in zconf.in.h zconf.h; do\
+	    test -r $(ZLIBSRC)/$$f &&\
+	    echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+	    $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+	done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+
+pnm2pngm.c: $(PROGSRC)/pnm2png.c
+	$(RM) $@
+	$(COPY) $(PROGSRC)/pnm2png.c $@
+
+# End of makefile for pnm2pngm
diff --git a/extern/libpng/contrib/pngminim/encoder/pngusr.dfa b/extern/libpng/contrib/pngminim/encoder/pngusr.dfa
new file mode 100644
index 0000000000..1fc24f3f2a
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/encoder/pngusr.dfa
@@ -0,0 +1,39 @@
+# pngminim/encoder/pngusr.dfa
+#
+# Copyright (c) 2010-2013 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# First all the build options off:
+
+everything = off
+
+# Switch on the write code - this makes a minimalist encoder
+
+option WRITE on
+
+# These 2 options are required if you need to read PBM (P1 or P4) files.
+option WRITE_INVERT on
+option WRITE_PACK on
+
+# You must choose fixed or floating point arithmetic:
+# option FLOATING_POINT on
+
+option FIXED_POINT on
+
+# You must chose the internal fixed point implementation or to
+# use the system floating point.  The latter is considerably
+# smaller (by about 1kbyte on an x86 system):
+# option FLOATING_ARITHMETIC on
+
+option FLOATING_ARITHMETIC off
+
+# Your program will probably need other options.  The example
+# program here, pnm2pngm, requires the following.  Take a look
+# at pnglibconf.h to find out the full set of what has to be
+# enabled to make the following work.
+
+option SETJMP on
+option STDIO on
diff --git a/extern/libpng/contrib/pngminim/encoder/pngusr.h b/extern/libpng/contrib/pngminim/encoder/pngusr.h
new file mode 100644
index 0000000000..997d44fe90
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/encoder/pngusr.h
@@ -0,0 +1,23 @@
+/* minwrpngconf.h: headers to make a minimal png-write-only library
+ *
+ * Copyright (c) 2007, 2010-2013 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
+ */
+
+#ifndef MINWRPNGCONF_H
+#define MINWRPNGCONF_H
+
+/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
+
+/* List options to turn off features of the build that do not
+ * affect the API (so are not recorded in pnglibconf.h)
+ */
+
+#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
+
+#endif /* MINWRPNGCONF_H */
diff --git a/extern/libpng/contrib/pngminim/preader/README b/extern/libpng/contrib/pngminim/preader/README
new file mode 100644
index 0000000000..faa83560a7
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/preader/README
@@ -0,0 +1,15 @@
+This demonstrates the use of PNG_USER_CONFIG and pngusr.h
+
+The makefile builds a minimal read-only progressive decoder with
+embedded libpng, zlib and your system's X library.
+
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
+
+Edit makefile if required, to find your X library and include files,
+then
+
+    make ZLIBSRC=directory
+
+If you prefer to use the shared libraries, go to contrib/gregbook
+and build the rpng2-x application there.
diff --git a/extern/libpng/contrib/pngminim/preader/makefile b/extern/libpng/contrib/pngminim/preader/makefile
new file mode 100644
index 0000000000..b625199114
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/preader/makefile
@@ -0,0 +1,166 @@
+# Makefile for PngMinus (rpng2)
+# Linux / Unix
+
+#CC=cc
+CC=gcc
+LD=$(CC)
+
+# If awk fails try
+# make AWK=nawk
+
+# If cpp fails try
+# make CPP=/lib/cpp
+
+RM=rm -f
+COPY=cp
+
+#XINC = -I/usr/include			# old-style, stock X distributions
+#XLIB = -L/usr/lib/X11 -lX11		#  (including SGI IRIX)
+
+#XINC = -I/usr/openwin/include		# Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+
+XINC = -I/usr/X11R6/include		# new X distributions (X.org, etc.)
+XLIB = -L/usr/X11R6/lib -lX11
+#XLIB = -L/usr/X11R6/lib64 -lX11	# e.g., Red Hat on AMD64
+
+#XINC = -I/usr/local/include   		# FreeBSD
+#XLIB = -L/usr/local/lib -lX11
+
+#LIBS = $(XLIB)
+LIBS = $(XLIB) -lm                      #platforms that need libm
+
+CPPFLAGS=-I. $(XINC) -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall
+
+C=.c
+O=.o
+L=.a
+E=
+
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/gregbook
+
+# Zlib (minimal inflate requirements - crc32 is used by libpng)
+# zutil can be eliminated if you provide your own zcalloc and zcfree
+ZSRCS  = adler32$(C) crc32$(C) \
+	 inffast$(C) inflate$(C) inftrees$(C) \
+	 zutil$(C)
+
+# Standard headers
+ZH     = zlib.h crc32.h inffast.h inffixed.h \
+	 inflate.h inftrees.h zutil.h
+
+# Machine generated headers
+ZCONF  = zconf.h
+
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+
+ZOBJS  = adler32$(O) crc32$(O) \
+	 inffast$(O) inflate$(O) inftrees$(O) \
+	 zutil$(O)
+
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+	pngpread$(C) pngread$(C) pngrio$(C) pngrtran$(C) pngrutil$(C) \
+	pngset$(C) pngtrans$(C)
+
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+
+# Machine generated headers
+PNGCONF=pnglibconf.h
+
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+	pngpread$(O) pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) \
+	pngset$(O) pngtrans$(O)
+
+PROGSRCS= rpng2-x$(C) readpng2$(C)
+PROGHDRS= readpng2.h
+PROGDOCS= COPYING LICENSE
+PROGOBJS= rpng2-x$(O) readpng2$(O)
+
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+# dependencies
+
+all: $(PROGDOCS) rpng2-x$(E)
+
+rpng2-x$(E): $(OBJS)
+	$(LD) -o rpng2-x$(E) $(OBJS) $(LIBS)
+
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
+	$(PNGSRC)/scripts/pnglibconf.dfa \
+	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+	$(RM) pnglibconf.h pnglibconf.dfn
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
+	    DFA_XTRA="pngusr.dfa" $@
+
+clean:
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) clean
+	$(RM) rpng2-x$(O)
+	$(RM) rpng2-x$(E)
+	$(RM) $(OBJS)
+
+# distclean also removes the copied source and headers
+distclean: clean
+	$(RM) -r scripts # historical reasons
+	$(RM) $(PNGSRCS) $(PNGH)
+	$(RM) $(ZSRCS) $(ZH) $(ZCONF)
+	$(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+	$(RM) $@
+	$(COPY) $(PNGSRC)/$@ $@
+
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+	$(RM) $@
+	$(COPY) $(ZLIBSRC)/$@ $@
+
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+	$(RM) $@
+	@for f in zconf.h.in zconf.in.h zconf.h; do\
+	    test -r $(ZLIBSRC)/$$f &&\
+	    echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+	    $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+	done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+
+$(PROGSRCS) $(PROGHDRS) $(PROGDOCS): $(PROGSRC)/$@
+	$(RM) $@
+	$(COPY) $(PROGSRC)/$@ $@
+
+# End of makefile for rpng2-x
diff --git a/extern/libpng/contrib/pngminim/preader/pngusr.dfa b/extern/libpng/contrib/pngminim/preader/pngusr.dfa
new file mode 100644
index 0000000000..ac297f41bd
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/preader/pngusr.dfa
@@ -0,0 +1,40 @@
+# pngminim/preader/pngusr.dfa
+#
+# Copyright (c) 2010-2013 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# First all the build options off:
+
+everything = off
+
+# Just switch on the progressive read code
+
+option PROGRESSIVE_READ on
+
+# You may choose fixed or floating point APIs:
+# option FLOATING_POINT on
+
+option FIXED_POINT on
+
+# You must chose the internal fixed point implementation or to
+# use the system floating point.  The latter is considerably
+# smaller (by about 1kbyte on an x86 system):
+
+option FLOATING_ARITHMETIC on
+# option FLOATING_ARITHMETIC off
+
+# Your program will probably need other options.  The example
+# program here, rpng2-x, requires the following.  Take a look
+# at pnglibconf.h to find out the full set of what has to be
+# enabled to make the following work.
+
+option SETJMP on
+option STDIO on
+option READ_bKGD on
+option READ_GAMMA on
+option READ_EXPAND on
+option READ_STRIP_16_TO_8 on
+option READ_GRAY_TO_RGB on
diff --git a/extern/libpng/contrib/pngminim/preader/pngusr.h b/extern/libpng/contrib/pngminim/preader/pngusr.h
new file mode 100644
index 0000000000..80db3bb171
--- /dev/null
+++ b/extern/libpng/contrib/pngminim/preader/pngusr.h
@@ -0,0 +1,23 @@
+/* minrdpngconf.h: headers to make a minimal png-read-only library
+ *
+ * Copyright (c) 2009, 2010-2013 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
+ */
+
+#ifndef MINPRDPNGCONF_H
+#define MINPRDPNGCONF_H
+
+/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
+
+/* List options to turn off features of the build that do not
+ * affect the API (so are not recorded in pnglibconf.h)
+ */
+
+#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
+
+#endif /* MINPRDPNGCONF_H */
diff --git a/extern/libpng/contrib/pngminus/CHANGES.txt b/extern/libpng/contrib/pngminus/CHANGES.txt
new file mode 100644
index 0000000000..4e64e5ee61
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/CHANGES.txt
@@ -0,0 +1,13 @@
+
+pnm2png / png2pnm --- conversion from PBM/PGM/PPM-file to PNG-file
+copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+
+version 1.0 - 1999.10.15 - First version.
+        1.1 - 2015.07.29 - Fixed leaks (Glenn Randers-Pehrson)
+        1.2 - 2017.04.22 - Add buffer-size check
+        1.3 - 2017.08.24 - Fix potential overflow in buffer-size check
+                           (Glenn Randers-Pehrson)
+        1.4 - 2017.08.28 - Add PNGMINUS_UNUSED (Christian Hesse)
+        1.5 - 2018.08.05 - Fix buffer overflow in tokenizer (Cosmin Truta)
+        1.6 - 2018.08.05 - Improve portability and fix style (Cosmin Truta)
+        1.7 - 2019.01.22 - Change license to MIT (Willem van Schaik)
diff --git a/extern/libpng/contrib/pngminus/CMakeLists.txt b/extern/libpng/contrib/pngminus/CMakeLists.txt
new file mode 100644
index 0000000000..1f815a5825
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/CMakeLists.txt
@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.1)
+cmake_policy(VERSION 3.1)
+
+project(PNGMINUS C)
+
+option(PNGMINUS_USE_STATIC_LIBRARIES "Use the static library builds" ON)
+
+# libpng
+add_subdirectory(../.. libpng)
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/../..)
+include_directories(${CMAKE_CURRENT_BINARY_DIR}/libpng)
+if(PNGMINUS_USE_STATIC_LIBRARIES)
+  set(PNGMINUS_PNG_LIBRARY png_static)
+else()
+  set(PNGMINUS_PNG_LIBRARY png)
+endif()
+
+# png2pnm
+add_executable(png2pnm png2pnm.c)
+target_link_libraries(png2pnm ${PNGMINUS_PNG_LIBRARY})
+
+# pnm2png
+add_executable(pnm2png pnm2png.c)
+target_link_libraries(pnm2png ${PNGMINUS_PNG_LIBRARY})
diff --git a/extern/libpng/contrib/pngminus/LICENSE.txt b/extern/libpng/contrib/pngminus/LICENSE.txt
new file mode 100644
index 0000000000..00878a9a60
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/LICENSE.txt
@@ -0,0 +1,22 @@
+
+pnm2png / png2pnm --- conversion from PBM/PGM/PPM-file to PNG-file
+
+copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+The software is provided "as is", without warranty of any kind, express or
+implied, including but not limited to the warranties of merchantability,
+fitness for a particular purpose and noninfringement. In no event shall the
+authors or copyight holders be liable for any claim, damages or other
+liability, whether in an action of contract, tort or otherwise, arising from,
+out of or in connection with the software or the use or other dealings in the
+software.
diff --git a/extern/libpng/contrib/pngminus/Makefile b/extern/libpng/contrib/pngminus/Makefile
new file mode 100644
index 0000000000..4bba079611
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/Makefile
@@ -0,0 +1,62 @@
+# Makefile for PngMinus (png2pnm and pnm2png)
+# Linux / Unix
+
+#CC = cc
+CC = gcc
+LD = $(CC)
+
+RM = rm -f
+
+PNGINC = -I../..
+PNGLIB_SHARED = -L../.. -lpng
+PNGLIB_STATIC = ../../libpng.a
+
+# Uncomment the following if you have a custom zlib build at ../../../zlib
+#ZINC = -I../../../zlib
+#ZLIB_SHARED = -L../../../zlib -lz
+#ZLIB_STATIC = ../../../zlib/libz.a
+
+# Use the system zlib otherwise
+ZLIB_SHARED = -lz
+ZLIB_STATIC = -lz
+
+CPPFLAGS = $(PNGINC) $(ZINC)
+CFLAGS =
+LDFLAGS =
+LIBS_SHARED = $(PNGLIB_SHARED) $(ZLIB_SHARED)
+LIBS_STATIC = $(PNGLIB_STATIC) $(ZLIB_STATIC)
+
+EXEEXT =
+#EXEEXT = .exe
+
+# dependencies
+
+all: png2pnm$(EXEEXT) pnm2png$(EXEEXT) png2pnm-static$(EXEEXT) pnm2png-static$(EXEEXT)
+
+png2pnm.o: png2pnm.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) png2pnm.c
+
+pnm2png.o: pnm2png.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) pnm2png.c
+
+png2pnm$(EXEEXT): png2pnm.o
+	$(LD) $(LDFLAGS) -o png2pnm$(EXEEXT) png2pnm.o $(LIBS_SHARED) -lm
+
+pnm2png$(EXEEXT): pnm2png.o
+	$(LD) $(LDFLAGS) -o pnm2png$(EXEEXT) pnm2png.o $(LIBS_SHARED) -lm
+
+png2pnm-static$(EXEEXT): png2pnm.o
+	$(LD) $(LDFLAGS) -o png2pnm-static$(EXEEXT) png2pnm.o $(LIBS_STATIC) -lm
+
+pnm2png-static$(EXEEXT): pnm2png.o
+	$(LD) $(LDFLAGS) -o pnm2png-static$(EXEEXT) pnm2png.o $(LIBS_STATIC) -lm
+
+clean:
+	$(RM) png2pnm.o
+	$(RM) pnm2png.o
+	$(RM) png2pnm$(EXEEXT)
+	$(RM) pnm2png$(EXEEXT)
+	$(RM) png2pnm-static$(EXEEXT)
+	$(RM) pnm2png-static$(EXEEXT)
+
+# End of makefile for png2pnm / pnm2png
diff --git a/extern/libpng/contrib/pngminus/README.txt b/extern/libpng/contrib/pngminus/README.txt
new file mode 100644
index 0000000000..f7f6ecb3a5
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/README.txt
@@ -0,0 +1,120 @@
+PngMinus
+--------
+(copyright Willem van Schaik, 1999-2019)
+
+
+
+Some history
+------------
+Soon after the creation of PNG in 1995, the need was felt for a set of
+pnmtopng / pngtopnm utilities. Independently Alexander Lehmann and I
+(Willem van Schaik) started such a project. Luckily we discovered this
+and merged the two, which later became part of NetPBM, available from
+SourceForge.
+
+These two utilities have many, many options and make use of most of the
+features of PNG, like gamma, alpha, sbit, text-chunks, etc. This makes
+the utilities quite complex and by now not anymore very maintainable.
+When we wrote these programs, libpng was still in an early stage.
+Therefore, lots of the functionality that we put in our software can now
+be done using transform-functions in libpng.
+
+Finally, to compile these programs, you need to have installed and
+compiled three libraries: libpng, zlib and netpbm. Especially the latter
+makes the whole setup a bit bulky. But that's unavoidable given the many
+features of pnmtopng.
+
+
+What now (1999)
+---------------
+At this moment libpng is in a very stable state and can do much of the
+work done in pnmtopng. Also, pnmtopng needs to be upgraded to the new
+interface of libpng. Hence, it is time for a rewrite from the ground up
+of pnmtopng and pngtopnm. This will happen in the near future (stay
+tuned). The new package will get a different name to distinguish it from
+the old one: PngPlus.
+
+To experiment a bit with the new interface of libpng, I started off with
+a small prototype that contains only the basic functionality. It doesn't
+have any of the options to read or write special chunks and it will do
+no gamma correction. But this makes it also a simple program that is
+quite easy to understand and can serve well as a template for other
+software developments. By now there are of course a couple of programs,
+like Greg Roelofs' rpng/wpng, that can be used just as good.
+
+
+Can and can not
+---------------
+As this is the small brother of the future PngPlus, I called this fellow
+PngMinus. Because I started this development in good-old Turbo-C, I
+avoided the use the netpbm library, which requires DOS extenders. Again,
+another reason to call it PngMinus (minus netpbm :-). So, part of the
+program are some elementary routines to read / write pgm- and ppm-files.
+It does not handle B&W pbm-files, but instead you could do pgm with bit-
+depth 1.
+
+The downside of this approach is that you can not use them on images
+that require blocks of memory bigger than 64k (the DOS version). For
+larger images you will get an out-of-memory error.
+
+As said before, PngMinus doesn't correct for gamma. When reading
+png-files you can do this just as well by piping the output of png2pnm
+to pnmgamma, one of the standard PbmPlus tools. This same scenario will
+most probably also be followed in the full-blown future PngPlus, with
+the addition of course of the possibility to create gamma-chunks when
+writing png-files.
+
+On the other hand it supports alpha-channels. When reading a png-image
+you can write the alpha-channel into a pgm-file. And when creating an
+RGB+A png-image, you just combine a ppm-file with a corresponding
+pgm-file containing the alpha-channel. When reading, transparency chunks
+are converted into an alpha-channel and from there on treated the same
+way.
+
+Finally you can opt for writing ascii or binary pgm- and ppm-files. When
+the bit-depth is 16, the format will always be ascii.
+
+
+Using it
+--------
+To distinguish them from pnmtopng and PngPlus, the utilities are named
+png2pnm and pnm2png (2 instead of to). The input- and output-files can
+be given as parameters or through redirection. Therefore the programs
+can be part of a pipe.
+
+To list the options type "png2pnm -h" or "pnm2png -h".
+
+
+Just like Scandinavian furniture
+--------------------------------
+You have to put it together yourself. I developed the software on MS-DOS
+with Turbo-C 3.0 and RedHat Linux 4.2 with gcc. In both cases I used
+libpng-1.0.4 and zlib-1.1.3. By now (2019) it is twenty years later and
+more current versions are OK.
+
+The makefile assumes that the libpng libraries can be found in ../.. and
+libz in ../../../zlib. But you can change this to for example ../libpng
+and ../zlib. The makefile creates two versions of each program, one with
+static library support and the other using shared libraries.
+
+If you create a ../pngsuite directory and then store the basn####.png
+files from PngSuite (http://www.schaik.com/pngsuite/) in there, you can
+test the proper functioning of PngMinus by running pngminus.sh.
+
+
+Warranty
+-------
+Please, remember that this was just a small experiment to learn a few
+things. It will have many unforeseen features <vbg> ... who said bugs? Use
+it when you are in need for something simple or when you want a starting
+point for developing your own stuff.
+
+
+The end
+-------
+Willem van Schaik
+mailto:willem at schaik dot com
+http://www.schaik.com/png/
+
+Oct 1999, Jan 2019
+
diff --git a/extern/libpng/contrib/pngminus/makevms.com b/extern/libpng/contrib/pngminus/makevms.com
new file mode 100644
index 0000000000..00561bcd0d
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/makevms.com
@@ -0,0 +1,92 @@
+$!------------------------------------------------------------------------------
+$! make Contrib programs of libpng under OpenVMS
+$!
+$!
+$! Look for the compiler used
+$!
+$ zlibsrc = "[---.zlib]"
+$ ccopt="/include=(''zlibsrc',[--])"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$ open/write lopt lib.opt
+$ write lopt "[--]libpng.olb/lib"
+$ write lopt "''zlibsrc'libz.olb/lib"
+$ close lopt
+$ open/write xopt x11.opt
+$ write xopt "sys$library:decw$xlibshr.exe/share"
+$ close xopt
+$ write sys$output "Compiling PNG contrib programs ..."
+$   write sys$output "Building pnm2png..."
+$   CALL MAKE pnm2png.OBJ "cc ''CCOPT' pnm2png" -
+	pnm2png.c
+$   call make pnm2png.exe -
+	"LINK pnm2png,lib.opt/opt" -
+	pnm2png.obj
+$   write sys$output "Building png2pnm..."
+$   CALL MAKE png2pnm.OBJ "cc ''CCOPT' png2pnm" -
+	png2pnm.c
+$   call make png2pnm.exe -
+	"LINK png2pnm,lib.opt/opt" -
+	png2pnm.obj
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE
diff --git a/extern/libpng/contrib/pngminus/png2pnm.bat b/extern/libpng/contrib/pngminus/png2pnm.bat
new file mode 100755
index 0000000000..a2798c3403
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/png2pnm.bat
@@ -0,0 +1,41 @@
+REM -- grayscale
+png2pnm.exe -noraw ..\pngsuite\basn0g01.png basn0g01.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g02.png basn0g02.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g04.png basn0g04.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g08.png basn0g08.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g16.png basn0g16.pgm
+REM -- full-color
+png2pnm.exe -noraw ..\pngsuite\basn2c08.png basn2c08.ppm
+png2pnm.exe -noraw ..\pngsuite\basn2c16.png basn2c16.ppm
+REM -- paletted
+png2pnm.exe -noraw ..\pngsuite\basn3p01.png basn3p01.ppm
+png2pnm.exe -noraw ..\pngsuite\basn3p02.png basn3p02.ppm
+png2pnm.exe -noraw ..\pngsuite\basn3p04.png basn3p04.ppm
+png2pnm.exe -noraw ..\pngsuite\basn3p08.png basn3p08.ppm
+REM -- gray with alpha-channel
+png2pnm.exe -noraw ..\pngsuite\basn4a08.png basn4a08.pgm
+png2pnm.exe -noraw ..\pngsuite\basn4a16.png basn4a16.pgm
+REM -- color with alpha-channel
+png2pnm.exe -noraw -alpha basn6a08.pgm ..\pngsuite\basn6a08.png basn6a08.ppm
+png2pnm.exe -noraw -alpha basn6a16.pgm ..\pngsuite\basn6a16.png basn6a16.ppm
+REM -- grayscale
+png2pnm.exe -raw ..\pngsuite\basn0g01.png rawn0g01.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g02.png rawn0g02.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g04.png rawn0g04.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g08.png rawn0g08.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g16.png rawn0g16.pgm
+REM -- full-color
+png2pnm.exe -raw ..\pngsuite\basn2c08.png rawn2c08.ppm
+png2pnm.exe -raw ..\pngsuite\basn2c16.png rawn2c16.ppm
+REM -- paletted
+png2pnm.exe -raw ..\pngsuite\basn3p01.png rawn3p01.ppm
+png2pnm.exe -raw ..\pngsuite\basn3p02.png rawn3p02.ppm
+png2pnm.exe -raw ..\pngsuite\basn3p04.png rawn3p04.ppm
+png2pnm.exe -raw ..\pngsuite\basn3p08.png rawn3p08.ppm
+REM -- gray with alpha-channel
+png2pnm.exe -raw ..\pngsuite\basn4a08.png rawn4a08.pgm
+png2pnm.exe -raw ..\pngsuite\basn4a16.png rawn4a16.pgm
+REM -- color with alpha-channel
+png2pnm.exe -noraw -alpha rawn6a08.pgm ..\pngsuite\basn6a08.png rawn6a08.ppm
+png2pnm.exe -noraw -alpha rawn6a16.pgm ..\pngsuite\basn6a16.png rawn6a16.ppm
+
diff --git a/extern/libpng/contrib/pngminus/png2pnm.c b/extern/libpng/contrib/pngminus/png2pnm.c
new file mode 100644
index 0000000000..5fef7ed142
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/png2pnm.c
@@ -0,0 +1,427 @@
+/*
+ *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
+ *  copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+ *
+ *  This software is released under the MIT license. For conditions of
+ *  distribution and use, see the LICENSE file part of this package.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+
+#ifndef BOOL
+#define BOOL unsigned char
+#endif
+#ifndef TRUE
+#define TRUE (BOOL) 1
+#endif
+#ifndef FALSE
+#define FALSE (BOOL) 0
+#endif
+
+/* make png2pnm verbose so we can find problems (needs to be before png.h) */
+#ifndef PNG_DEBUG
+#define PNG_DEBUG 0
+#endif
+
+#include "png.h"
+
+/* function prototypes */
+
+int main (int argc, char *argv[]);
+void usage ();
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
+              BOOL raw, BOOL alpha);
+
+/*
+ *  main
+ */
+
+int main (int argc, char *argv[])
+{
+  FILE *fp_rd = stdin;
+  FILE *fp_wr = stdout;
+  FILE *fp_al = NULL;
+  BOOL raw = TRUE;
+  BOOL alpha = FALSE;
+  int argi;
+
+  for (argi = 1; argi < argc; argi++)
+  {
+    if (argv[argi][0] == '-')
+    {
+      switch (argv[argi][1])
+      {
+        case 'n':
+          raw = FALSE;
+          break;
+        case 'r':
+          raw = TRUE;
+          break;
+        case 'a':
+          alpha = TRUE;
+          argi++;
+          if ((fp_al = fopen (argv[argi], "wb")) == NULL)
+          {
+            fprintf (stderr, "PNM2PNG\n");
+            fprintf (stderr, "Error:  cannot create alpha-channel file %s\n",
+                     argv[argi]);
+            exit (1);
+          }
+          break;
+        case 'h':
+        case '?':
+          usage ();
+          exit (0);
+          break;
+        default:
+          fprintf (stderr, "PNG2PNM\n");
+          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
+          usage ();
+          exit (1);
+          break;
+      } /* end switch */
+    }
+    else if (fp_rd == stdin)
+    {
+      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
+      {
+        fprintf (stderr, "PNG2PNM\n");
+        fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else if (fp_wr == stdout)
+    {
+      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
+      {
+        fprintf (stderr, "PNG2PNM\n");
+        fprintf (stderr, "Error:  cannot create file %s\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else
+    {
+      fprintf (stderr, "PNG2PNM\n");
+      fprintf (stderr, "Error:  too many parameters\n");
+      usage ();
+      exit (1);
+    }
+  } /* end for */
+
+#if defined(O_BINARY) && (O_BINARY != 0)
+  /* set stdin/stdout if required to binary */
+  if (fp_rd == stdin)
+    setmode (fileno (stdin), O_BINARY);
+  if ((raw) && (fp_wr == stdout))
+    setmode (fileno (stdout), O_BINARY);
+#endif
+
+  /* call the conversion program itself */
+  if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE)
+  {
+    fprintf (stderr, "PNG2PNM\n");
+    fprintf (stderr, "Error:  unsuccessful conversion of PNG-image\n");
+    exit (1);
+  }
+
+  /* close input file */
+  fclose (fp_rd);
+  /* close output file */
+  fclose (fp_wr);
+  /* close alpha file */
+  if (alpha)
+    fclose (fp_al);
+
+  return 0;
+}
+
+/*
+ *  usage
+ */
+
+void usage ()
+{
+  fprintf (stderr, "PNG2PNM\n");
+  fprintf (stderr, "   by Willem van Schaik, 1999\n");
+  fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
+  fprintf (stderr, "   or:  ... | png2pnm [options]\n");
+  fprintf (stderr, "Options:\n");
+  fprintf (stderr,
+      "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
+  fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
+  fprintf (stderr,
+      "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
+  fprintf (stderr, "   -h | -?  print this help-information\n");
+}
+
+/*
+ *  png2pnm
+ */
+
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
+              BOOL raw, BOOL alpha)
+{
+  png_struct    *png_ptr = NULL;
+  png_info      *info_ptr = NULL;
+  png_byte      buf[8];
+  png_byte      *png_pixels = NULL;
+  png_byte      **row_pointers = NULL;
+  png_byte      *pix_ptr = NULL;
+  png_uint_32   row_bytes;
+
+  png_uint_32   width;
+  png_uint_32   height;
+  int           bit_depth;
+  int           channels;
+  int           color_type;
+  int           alpha_present;
+  int           row, col;
+  int           ret;
+  int           i;
+  long          dep_16;
+
+  /* read and check signature in PNG file */
+  ret = fread (buf, 1, 8, png_file);
+  if (ret != 8)
+    return FALSE;
+
+  ret = png_sig_cmp (buf, 0, 8);
+  if (ret != 0)
+    return FALSE;
+
+  /* create png and info structures */
+
+  png_ptr = png_create_read_struct (png_get_libpng_ver(NULL),
+                                    NULL, NULL, NULL);
+  if (!png_ptr)
+    return FALSE; /* out of memory */
+
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_read_struct (&png_ptr, NULL, NULL);
+    return FALSE; /* out of memory */
+  }
+
+  if (setjmp (png_jmpbuf (png_ptr)))
+  {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    return FALSE;
+  }
+
+  /* set up the input control for C streams */
+  png_init_io (png_ptr, png_file);
+  png_set_sig_bytes (png_ptr, 8); /* we already read the 8 signature bytes */
+
+  /* read the file information */
+  png_read_info (png_ptr, info_ptr);
+
+  /* get size and bit-depth of the PNG-image */
+  png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+                NULL, NULL, NULL);
+
+  /* set-up the transformations */
+
+  /* transform paletted images into full-color rgb */
+  if (color_type == PNG_COLOR_TYPE_PALETTE)
+    png_set_expand (png_ptr);
+  /* expand images to bit-depth 8 (only applicable for grayscale images) */
+  if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+    png_set_expand (png_ptr);
+  /* transform transparency maps into full alpha-channel */
+  if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
+    png_set_expand (png_ptr);
+
+#ifdef NJET
+  /* downgrade 16-bit images to 8-bit */
+  if (bit_depth == 16)
+    png_set_strip_16 (png_ptr);
+  /* transform grayscale images into full-color */
+  if (color_type == PNG_COLOR_TYPE_GRAY ||
+      color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    png_set_gray_to_rgb (png_ptr);
+  /* only if file has a file gamma, we do a correction */
+  if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))
+    png_set_gamma (png_ptr, (double) 2.2, file_gamma);
+#endif
+
+  /* all transformations have been registered; now update info_ptr data,
+   * get rowbytes and channels, and allocate image memory */
+
+  png_read_update_info (png_ptr, info_ptr);
+
+  /* get the new color-type and bit-depth (after expansion/stripping) */
+  png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+                NULL, NULL, NULL);
+
+  /* check for 16-bit files */
+  if (bit_depth == 16)
+  {
+    raw = FALSE;
+#if defined(O_BINARY) && (O_BINARY != 0)
+    setmode (fileno (pnm_file), O_BINARY);
+#endif
+  }
+
+  /* calculate new number of channels and store alpha-presence */
+  if (color_type == PNG_COLOR_TYPE_GRAY)
+    channels = 1;
+  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    channels = 2;
+  else if (color_type == PNG_COLOR_TYPE_RGB)
+    channels = 3;
+  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+    channels = 4;
+  else
+    channels = 0; /* should never happen */
+  alpha_present = (channels - 1) % 2;
+
+  /* check if alpha is expected to be present in file */
+  if (alpha && !alpha_present)
+  {
+    fprintf (stderr, "PNG2PNM\n");
+    fprintf (stderr, "Error:  PNG-file doesn't contain alpha channel\n");
+    exit (1);
+  }
+
+  /* row_bytes is the width x number of channels x (bit-depth / 8) */
+  row_bytes = png_get_rowbytes (png_ptr, info_ptr);
+
+  if ((row_bytes == 0) ||
+      ((size_t) height > (size_t) (-1) / (size_t) row_bytes))
+  {
+    /* too big */
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    return FALSE;
+  }
+  if ((png_pixels = (png_byte *)
+       malloc ((size_t) row_bytes * (size_t) height)) == NULL)
+  {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    return FALSE;
+  }
+
+  if ((row_pointers = (png_byte **)
+       malloc ((size_t) height * sizeof (png_byte *))) == NULL)
+  {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    free (png_pixels);
+    return FALSE;
+  }
+
+  /* set the individual row_pointers to point at the correct offsets */
+  for (i = 0; i < ((int) height); i++)
+    row_pointers[i] = png_pixels + i * row_bytes;
+
+  /* now we can go ahead and just read the whole image */
+  png_read_image (png_ptr, row_pointers);
+
+  /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
+  png_read_end (png_ptr, info_ptr);
+
+  /* clean up after the read, and free any memory allocated - REQUIRED */
+  png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+
+  /* write header of PNM file */
+
+  if ((color_type == PNG_COLOR_TYPE_GRAY) ||
+      (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+  {
+    fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2");
+    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
+    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+  else if ((color_type == PNG_COLOR_TYPE_RGB) ||
+           (color_type == PNG_COLOR_TYPE_RGB_ALPHA))
+  {
+    fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3");
+    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
+    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+
+  /* write header of PGM file with alpha channel */
+
+  if ((alpha) &&
+      ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||
+       (color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+  {
+    fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2");
+    fprintf (alpha_file, "%d %d\n", (int) width, (int) height);
+    fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+
+  /* write data to PNM file */
+  pix_ptr = png_pixels;
+
+  for (row = 0; row < (int) height; row++)
+  {
+    for (col = 0; col < (int) width; col++)
+    {
+      for (i = 0; i < (channels - alpha_present); i++)
+      {
+        if (raw)
+        {
+          fputc ((int) *pix_ptr++, pnm_file);
+        }
+        else
+        {
+          if (bit_depth == 16)
+          {
+            dep_16 = (long) *pix_ptr++;
+            fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++));
+          }
+          else
+          {
+            fprintf (pnm_file, "%ld ", (long) *pix_ptr++);
+          }
+        }
+      }
+      if (alpha_present)
+      {
+        if (!alpha)
+        {
+          pix_ptr++; /* alpha */
+          if (bit_depth == 16)
+            pix_ptr++;
+        }
+        else /* output alpha-channel as pgm file */
+        {
+          if (raw)
+          {
+            fputc ((int) *pix_ptr++, alpha_file);
+          }
+          else
+          {
+            if (bit_depth == 16)
+            {
+              dep_16 = (long) *pix_ptr++;
+              fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);
+            }
+            else
+            {
+              fprintf (alpha_file, "%ld ", (long) *pix_ptr++);
+            }
+          }
+        }
+      } /* end if alpha_present */
+
+      if (!raw)
+        if (col % 4 == 3)
+          fprintf (pnm_file, "\n");
+    } /* end for col */
+
+    if (!raw)
+      if (col % 4 != 0)
+        fprintf (pnm_file, "\n");
+  } /* end for row */
+
+  if (row_pointers != NULL)
+    free (row_pointers);
+  if (png_pixels != NULL)
+    free (png_pixels);
+
+  return TRUE;
+
+} /* end of source */
diff --git a/extern/libpng/contrib/pngminus/png2pnm.sh b/extern/libpng/contrib/pngminus/png2pnm.sh
new file mode 100755
index 0000000000..756126a53c
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/png2pnm.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+# -- grayscale
+./png2pnm -noraw ../pngsuite/basn0g01.png basn0g01.pgm
+./png2pnm -noraw ../pngsuite/basn0g02.png basn0g02.pgm
+./png2pnm -noraw ../pngsuite/basn0g04.png basn0g04.pgm
+./png2pnm -noraw ../pngsuite/basn0g08.png basn0g08.pgm
+./png2pnm -noraw ../pngsuite/basn0g16.png basn0g16.pgm
+# -- full-color
+./png2pnm -noraw ../pngsuite/basn2c08.png basn2c08.ppm
+./png2pnm -noraw ../pngsuite/basn2c16.png basn2c16.ppm
+# -- paletted
+./png2pnm -noraw ../pngsuite/basn3p01.png basn3p01.ppm
+./png2pnm -noraw ../pngsuite/basn3p02.png basn3p02.ppm
+./png2pnm -noraw ../pngsuite/basn3p04.png basn3p04.ppm
+./png2pnm -noraw ../pngsuite/basn3p08.png basn3p08.ppm
+# -- gray with alpha-channel
+./png2pnm -noraw ../pngsuite/basn4a08.png basn4a08.pgm
+./png2pnm -noraw ../pngsuite/basn4a16.png basn4a16.pgm
+# -- color with alpha-channel
+./png2pnm -noraw -alpha basn6a08.pgm ../pngsuite/basn6a08.png basn6a08.ppm
+./png2pnm -noraw -alpha basn6a16.pgm ../pngsuite/basn6a16.png basn6a16.ppm
+# -- grayscale
+./png2pnm -raw ../pngsuite/basn0g01.png rawn0g01.pgm
+./png2pnm -raw ../pngsuite/basn0g02.png rawn0g02.pgm
+./png2pnm -raw ../pngsuite/basn0g04.png rawn0g04.pgm
+./png2pnm -raw ../pngsuite/basn0g08.png rawn0g08.pgm
+./png2pnm -raw ../pngsuite/basn0g16.png rawn0g16.pgm
+# -- full-color
+./png2pnm -raw ../pngsuite/basn2c08.png rawn2c08.ppm
+./png2pnm -raw ../pngsuite/basn2c16.png rawn2c16.ppm
+# -- paletted
+./png2pnm -raw ../pngsuite/basn3p01.png rawn3p01.ppm
+./png2pnm -raw ../pngsuite/basn3p02.png rawn3p02.ppm
+./png2pnm -raw ../pngsuite/basn3p04.png rawn3p04.ppm
+./png2pnm -raw ../pngsuite/basn3p08.png rawn3p08.ppm
+# -- gray with alpha-channel
+./png2pnm -raw ../pngsuite/basn4a08.png rawn4a08.pgm
+./png2pnm -raw ../pngsuite/basn4a16.png rawn4a16.pgm
+# -- color with alpha-channel
+./png2pnm -noraw -alpha rawn6a08.pgm ../pngsuite/basn6a08.png rawn6a08.ppm
+./png2pnm -noraw -alpha rawn6a16.pgm ../pngsuite/basn6a16.png rawn6a16.ppm
+
diff --git a/extern/libpng/contrib/pngminus/pngminus.bat b/extern/libpng/contrib/pngminus/pngminus.bat
new file mode 100755
index 0000000000..fa60e7de07
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/pngminus.bat
@@ -0,0 +1,4 @@
+make
+call png2pnm.bat
+call pnm2png.bat
+
diff --git a/extern/libpng/contrib/pngminus/pngminus.sh b/extern/libpng/contrib/pngminus/pngminus.sh
new file mode 100755
index 0000000000..cc9b4a56e3
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/pngminus.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+make
+sh png2pnm.sh
+sh pnm2png.sh
+
diff --git a/extern/libpng/contrib/pngminus/pnm2png.bat b/extern/libpng/contrib/pngminus/pnm2png.bat
new file mode 100755
index 0000000000..c02b80becc
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/pnm2png.bat
@@ -0,0 +1,41 @@
+REM -- grayscale
+pnm2png.exe basn0g01.pgm basn0g01.png
+pnm2png.exe basn0g02.pgm basn0g02.png
+pnm2png.exe basn0g04.pgm basn0g04.png
+pnm2png.exe basn0g08.pgm basn0g08.png
+pnm2png.exe basn0g16.pgm basn0g16.png
+REM -- full-color
+pnm2png.exe basn2c08.ppm basn2c08.png
+pnm2png.exe basn2c16.ppm basn2c16.png
+REM -- paletted
+pnm2png.exe basn3p01.ppm basn3p01.png
+pnm2png.exe basn3p02.ppm basn3p02.png
+pnm2png.exe basn3p04.ppm basn3p04.png
+pnm2png.exe basn3p08.ppm basn3p08.png
+REM -- gray with alpha-channel
+pnm2png.exe -alpha basn6a08.pgm basn4a08.pgm basn4a08.png
+pnm2png.exe -alpha basn6a16.pgm basn4a16.pgm basn4a16.png
+REM -- color with alpha-channel
+pnm2png.exe -alpha basn6a08.pgm basn6a08.ppm basn6a08.png
+pnm2png.exe -alpha basn6a16.pgm basn6a16.ppm basn6a16.png
+REM -- grayscale
+pnm2png.exe rawn0g01.pgm rawn0g01.png
+pnm2png.exe rawn0g02.pgm rawn0g02.png
+pnm2png.exe rawn0g04.pgm rawn0g04.png
+pnm2png.exe rawn0g08.pgm rawn0g08.png
+pnm2png.exe rawn0g16.pgm rawn0g16.png
+REM -- full-color
+pnm2png.exe rawn2c08.ppm rawn2c08.png
+pnm2png.exe rawn2c16.ppm rawn2c16.png
+REM -- paletted
+pnm2png.exe rawn3p01.ppm rawn3p01.png
+pnm2png.exe rawn3p02.ppm rawn3p02.png
+pnm2png.exe rawn3p04.ppm rawn3p04.png
+pnm2png.exe rawn3p08.ppm rawn3p08.png
+REM -- gray with alpha-channel
+pnm2png.exe -alpha rawn6a08.pgm rawn4a08.pgm rawn4a08.png
+pnm2png.exe -alpha rawn6a16.pgm rawn4a16.pgm rawn4a16.png
+REM -- color with alpha-channel
+pnm2png.exe -alpha rawn6a08.pgm rawn6a08.ppm rawn6a08.png
+pnm2png.exe -alpha rawn6a16.pgm rawn6a16.ppm rawn6a16.png
+
diff --git a/extern/libpng/contrib/pngminus/pnm2png.c b/extern/libpng/contrib/pngminus/pnm2png.c
new file mode 100644
index 0000000000..a2c2551da9
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/pnm2png.c
@@ -0,0 +1,620 @@
+/*
+ *  pnm2png.c --- conversion from PBM/PGM/PPM-file to PNG-file
+ *  copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+ *
+ *  This software is released under the MIT license. For conditions of
+ *  distribution and use, see the LICENSE file part of this package.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+
+#ifndef BOOL
+#define BOOL unsigned char
+#endif
+#ifndef TRUE
+#define TRUE (BOOL) 1
+#endif
+#ifndef FALSE
+#define FALSE (BOOL) 0
+#endif
+
+/* make pnm2png verbose so we can find problems (needs to be before png.h) */
+#ifndef PNG_DEBUG
+#define PNG_DEBUG 0
+#endif
+
+#include "png.h"
+
+/* function prototypes */
+
+int main (int argc, char *argv[]);
+void usage ();
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file,
+              BOOL interlace, BOOL alpha);
+void get_token (FILE *pnm_file, char *token_buf, size_t token_buf_size);
+png_uint_32 get_data (FILE *pnm_file, int depth);
+png_uint_32 get_value (FILE *pnm_file, int depth);
+
+/*
+ *  main
+ */
+
+int main (int argc, char *argv[])
+{
+  FILE *fp_rd = stdin;
+  FILE *fp_al = NULL;
+  FILE *fp_wr = stdout;
+  BOOL interlace = FALSE;
+  BOOL alpha = FALSE;
+  int argi;
+
+  for (argi = 1; argi < argc; argi++)
+  {
+    if (argv[argi][0] == '-')
+    {
+      switch (argv[argi][1])
+      {
+        case 'i':
+          interlace = TRUE;
+          break;
+        case 'a':
+          alpha = TRUE;
+          argi++;
+          if ((fp_al = fopen (argv[argi], "rb")) == NULL)
+          {
+            fprintf (stderr, "PNM2PNG\n");
+            fprintf (stderr, "Error:  alpha-channel file %s does not exist\n",
+                     argv[argi]);
+            exit (1);
+          }
+          break;
+        case 'h':
+        case '?':
+          usage ();
+          exit (0);
+          break;
+        default:
+          fprintf (stderr, "PNM2PNG\n");
+          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
+          usage ();
+          exit (1);
+          break;
+      } /* end switch */
+    }
+    else if (fp_rd == stdin)
+    {
+      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
+      {
+        fprintf (stderr, "PNM2PNG\n");
+        fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else if (fp_wr == stdout)
+    {
+      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
+      {
+        fprintf (stderr, "PNM2PNG\n");
+        fprintf (stderr, "Error:  cannot create PNG-file %s\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else
+    {
+      fprintf (stderr, "PNM2PNG\n");
+      fprintf (stderr, "Error:  too many parameters\n");
+      usage ();
+      exit (1);
+    }
+  } /* end for */
+
+#if defined(O_BINARY) && (O_BINARY != 0)
+  /* set stdin/stdout to binary,
+   * we're reading the PNM always! in binary format
+   */
+  if (fp_rd == stdin)
+    setmode (fileno (stdin), O_BINARY);
+  if (fp_wr == stdout)
+    setmode (fileno (stdout), O_BINARY);
+#endif
+
+  /* call the conversion program itself */
+  if (pnm2png (fp_rd, fp_wr, fp_al, interlace, alpha) == FALSE)
+  {
+    fprintf (stderr, "PNM2PNG\n");
+    fprintf (stderr, "Error:  unsuccessful converting to PNG-image\n");
+    exit (1);
+  }
+
+  /* close input file */
+  fclose (fp_rd);
+  /* close output file */
+  fclose (fp_wr);
+  /* close alpha file */
+  if (alpha)
+    fclose (fp_al);
+
+  return 0;
+}
+
+/*
+ *  usage
+ */
+
+void usage ()
+{
+  fprintf (stderr, "PNM2PNG\n");
+  fprintf (stderr, "   by Willem van Schaik, 1999\n");
+  fprintf (stderr, "Usage:  pnm2png [options] <file>.<pnm> [<file>.png]\n");
+  fprintf (stderr, "   or:  ... | pnm2png [options]\n");
+  fprintf (stderr, "Options:\n");
+  fprintf (stderr, "   -i[nterlace]   write png-file with interlacing on\n");
+  fprintf (stderr,
+      "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
+  fprintf (stderr, "   -h | -?  print this help-information\n");
+}
+
+/*
+ *  pnm2png
+ */
+
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file,
+              BOOL interlace, BOOL alpha)
+{
+  png_struct    *png_ptr = NULL;
+  png_info      *info_ptr = NULL;
+  png_byte      *png_pixels = NULL;
+  png_byte      **row_pointers = NULL;
+  png_byte      *pix_ptr = NULL;
+  volatile png_uint_32 row_bytes;
+
+  char          type_token[16];
+  char          width_token[16];
+  char          height_token[16];
+  char          maxval_token[16];
+  volatile int  color_type = 1;
+  unsigned long ul_width = 0, ul_alpha_width = 0;
+  unsigned long ul_height = 0, ul_alpha_height = 0;
+  unsigned long ul_maxval = 0;
+  volatile png_uint_32 width = 0, height = 0;
+  volatile png_uint_32 alpha_width = 0, alpha_height = 0;
+  png_uint_32   maxval;
+  volatile int  bit_depth = 0;
+  int           channels = 0;
+  int           alpha_depth = 0;
+  int           alpha_present = 0;
+  int           row, col;
+  BOOL          raw, alpha_raw = FALSE;
+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+  BOOL          packed_bitmap = FALSE;
+#endif
+  png_uint_32   tmp16;
+  int           i;
+
+  /* read header of PNM file */
+
+  get_token (pnm_file, type_token, sizeof (type_token));
+  if (type_token[0] != 'P')
+  {
+    return FALSE;
+  }
+  else if ((type_token[1] == '1') || (type_token[1] == '4'))
+  {
+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+    raw = (type_token[1] == '4');
+    color_type = PNG_COLOR_TYPE_GRAY;
+    get_token (pnm_file, width_token, sizeof (width_token));
+    sscanf (width_token, "%lu", &ul_width);
+    width = (png_uint_32) ul_width;
+    get_token (pnm_file, height_token, sizeof (height_token));
+    sscanf (height_token, "%lu", &ul_height);
+    height = (png_uint_32) ul_height;
+    bit_depth = 1;
+    packed_bitmap = TRUE;
+#else
+    fprintf (stderr, "PNM2PNG built without PNG_WRITE_INVERT_SUPPORTED and\n");
+    fprintf (stderr, "PNG_WRITE_PACK_SUPPORTED can't read PBM (P1,P4) files\n");
+    return FALSE;
+#endif
+  }
+  else if ((type_token[1] == '2') || (type_token[1] == '5'))
+  {
+    raw = (type_token[1] == '5');
+    color_type = PNG_COLOR_TYPE_GRAY;
+    get_token (pnm_file, width_token, sizeof (width_token));
+    sscanf (width_token, "%lu", &ul_width);
+    width = (png_uint_32) ul_width;
+    get_token (pnm_file, height_token, sizeof (height_token));
+    sscanf (height_token, "%lu", &ul_height);
+    height = (png_uint_32) ul_height;
+    get_token (pnm_file, maxval_token, sizeof (maxval_token));
+    sscanf (maxval_token, "%lu", &ul_maxval);
+    maxval = (png_uint_32) ul_maxval;
+
+    if (maxval <= 1)
+      bit_depth = 1;
+    else if (maxval <= 3)
+      bit_depth = 2;
+    else if (maxval <= 15)
+      bit_depth = 4;
+    else if (maxval <= 255)
+      bit_depth = 8;
+    else if (maxval <= 65535U)
+      bit_depth = 16;
+    else /* maxval > 65535U */
+      return FALSE;
+  }
+  else if ((type_token[1] == '3') || (type_token[1] == '6'))
+  {
+    raw = (type_token[1] == '6');
+    color_type = PNG_COLOR_TYPE_RGB;
+    get_token (pnm_file, width_token, sizeof (width_token));
+    sscanf (width_token, "%lu", &ul_width);
+    width = (png_uint_32) ul_width;
+    get_token (pnm_file, height_token, sizeof (height_token));
+    sscanf (height_token, "%lu", &ul_height);
+    height = (png_uint_32) ul_height;
+    get_token (pnm_file, maxval_token, sizeof (maxval_token));
+    sscanf (maxval_token, "%lu", &ul_maxval);
+    maxval = (png_uint_32) ul_maxval;
+    if (maxval <= 1)
+      bit_depth = 1;
+    else if (maxval <= 3)
+      bit_depth = 2;
+    else if (maxval <= 15)
+      bit_depth = 4;
+    else if (maxval <= 255)
+      bit_depth = 8;
+    else if (maxval <= 65535U)
+      bit_depth = 16;
+    else /* maxval > 65535U */
+      return FALSE;
+  }
+  else
+  {
+    return FALSE;
+  }
+
+  /* read header of PGM file with alpha channel */
+
+  if (alpha)
+  {
+    if (color_type == PNG_COLOR_TYPE_GRAY)
+      color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+    if (color_type == PNG_COLOR_TYPE_RGB)
+      color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+
+    get_token (alpha_file, type_token, sizeof (type_token));
+    if (type_token[0] != 'P')
+    {
+      return FALSE;
+    }
+    else if ((type_token[1] == '2') || (type_token[1] == '5'))
+    {
+      alpha_raw = (type_token[1] == '5');
+      get_token (alpha_file, width_token, sizeof (width_token));
+      sscanf (width_token, "%lu", &ul_alpha_width);
+      alpha_width = (png_uint_32) ul_alpha_width;
+      if (alpha_width != width)
+        return FALSE;
+      get_token (alpha_file, height_token, sizeof (height_token));
+      sscanf (height_token, "%lu", &ul_alpha_height);
+      alpha_height = (png_uint_32) ul_alpha_height;
+      if (alpha_height != height)
+        return FALSE;
+      get_token (alpha_file, maxval_token, sizeof (maxval_token));
+      sscanf (maxval_token, "%lu", &ul_maxval);
+      maxval = (png_uint_32) ul_maxval;
+      if (maxval <= 1)
+        alpha_depth = 1;
+      else if (maxval <= 3)
+        alpha_depth = 2;
+      else if (maxval <= 15)
+        alpha_depth = 4;
+      else if (maxval <= 255)
+        alpha_depth = 8;
+      else if (maxval <= 65535U)
+        alpha_depth = 16;
+      else /* maxval > 65535U */
+        return FALSE;
+      if (alpha_depth != bit_depth)
+        return FALSE;
+    }
+    else
+    {
+      return FALSE;
+    }
+  } /* end if alpha */
+
+  /* calculate the number of channels and store alpha-presence */
+  if (color_type == PNG_COLOR_TYPE_GRAY)
+    channels = 1;
+  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    channels = 2;
+  else if (color_type == PNG_COLOR_TYPE_RGB)
+    channels = 3;
+  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+    channels = 4;
+#if 0
+  else
+    channels = 0; /* cannot happen */
+#endif
+
+  alpha_present = (channels - 1) % 2;
+
+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+  if (packed_bitmap)
+  {
+    /* row data is as many bytes as can fit width x channels x bit_depth */
+    row_bytes = (width * channels * bit_depth + 7) / 8;
+  }
+  else
+#endif
+  {
+    /* row_bytes is the width x number of channels x (bit-depth / 8) */
+    row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);
+  }
+
+  if ((row_bytes == 0) ||
+      ((size_t) height > (size_t) (-1) / (size_t) row_bytes))
+  {
+    /* too big */
+    return FALSE;
+  }
+  if ((png_pixels = (png_byte *)
+       malloc ((size_t) row_bytes * (size_t) height)) == NULL)
+  {
+    /* out of memory */
+    return FALSE;
+  }
+
+  /* read data from PNM file */
+  pix_ptr = png_pixels;
+
+  for (row = 0; row < (int) height; row++)
+  {
+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+    if (packed_bitmap)
+    {
+      for (i = 0; i < (int) row_bytes; i++)
+      {
+        /* png supports this format natively so no conversion is needed */
+        *pix_ptr++ = get_data (pnm_file, 8);
+      }
+    }
+    else
+#endif
+    {
+      for (col = 0; col < (int) width; col++)
+      {
+        for (i = 0; i < (channels - alpha_present); i++)
+        {
+          if (raw)
+          {
+            *pix_ptr++ = get_data (pnm_file, bit_depth);
+          }
+          else
+          {
+            if (bit_depth <= 8)
+            {
+              *pix_ptr++ = get_value (pnm_file, bit_depth);
+            }
+            else
+            {
+              tmp16 = get_value (pnm_file, bit_depth);
+              *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
+              pix_ptr++;
+              *pix_ptr = (png_byte) (tmp16 & 0xFF);
+              pix_ptr++;
+            }
+          }
+        }
+
+        if (alpha) /* read alpha-channel from pgm file */
+        {
+          if (alpha_raw)
+          {
+            *pix_ptr++ = get_data (alpha_file, alpha_depth);
+          }
+          else
+          {
+            if (alpha_depth <= 8)
+            {
+              *pix_ptr++ = get_value (alpha_file, bit_depth);
+            }
+            else
+            {
+              tmp16 = get_value (alpha_file, bit_depth);
+              *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
+              *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
+            }
+          }
+        } /* end if alpha */
+      } /* end if packed_bitmap */
+    } /* end for col */
+  } /* end for row */
+
+  /* prepare the standard PNG structures */
+  png_ptr = png_create_write_struct (png_get_libpng_ver(NULL),
+                                     NULL, NULL, NULL);
+  if (!png_ptr)
+  {
+    free (png_pixels);
+    return FALSE;
+  }
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_write_struct (&png_ptr, NULL);
+    free (png_pixels);
+    return FALSE;
+  }
+
+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+  if (packed_bitmap == TRUE)
+  {
+    png_set_packing (png_ptr);
+    png_set_invert_mono (png_ptr);
+  }
+#endif
+
+  if (setjmp (png_jmpbuf (png_ptr)))
+  {
+    png_destroy_write_struct (&png_ptr, &info_ptr);
+    free (png_pixels);
+    return FALSE;
+  }
+
+  /* initialize the png structure */
+  png_init_io (png_ptr, png_file);
+
+  /* we're going to write more or less the same PNG as the input file */
+  png_set_IHDR (png_ptr, info_ptr, width, height, bit_depth, color_type,
+                (!interlace) ? PNG_INTERLACE_NONE : PNG_INTERLACE_ADAM7,
+                PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+  /* write the file header information */
+  png_write_info (png_ptr, info_ptr);
+
+  /* if needed we will allocate memory for an new array of row-pointers */
+  if (row_pointers == NULL)
+  {
+    if ((row_pointers = (png_byte **)
+         malloc (height * sizeof (png_byte *))) == NULL)
+    {
+      png_destroy_write_struct (&png_ptr, &info_ptr);
+      free (png_pixels);
+      return FALSE;
+    }
+  }
+
+  /* set the individual row_pointers to point at the correct offsets */
+  for (i = 0; i < (int) height; i++)
+    row_pointers[i] = png_pixels + i * row_bytes;
+
+  /* write out the entire image data in one call */
+  png_write_image (png_ptr, row_pointers);
+
+  /* write the additional chunks to the PNG file (not really needed) */
+  png_write_end (png_ptr, info_ptr);
+
+  /* clean up after the write, and free any memory allocated */
+  png_destroy_write_struct (&png_ptr, &info_ptr);
+
+  if (row_pointers != NULL)
+    free (row_pointers);
+  if (png_pixels != NULL)
+    free (png_pixels);
+
+  return TRUE;
+} /* end of pnm2png */
+
+/*
+ * get_token - gets the first string after whitespace
+ */
+
+void get_token (FILE *pnm_file, char *token_buf, size_t token_buf_size)
+{
+  size_t i = 0;
+  int ret;
+
+  /* remove white-space and comment lines */
+  do
+  {
+    ret = fgetc (pnm_file);
+    if (ret == '#')
+    {
+      /* the rest of this line is a comment */
+      do
+      {
+        ret = fgetc (pnm_file);
+      }
+      while ((ret != '\n') && (ret != '\r') && (ret != EOF));
+    }
+    if (ret == EOF) break;
+    token_buf[i] = (char) ret;
+  }
+  while ((ret == '\n') || (ret == '\r') || (ret == ' '));
+
+  /* read string */
+  do
+  {
+    ret = fgetc (pnm_file);
+    if (ret == EOF) break;
+    if (++i == token_buf_size - 1) break;
+    token_buf[i] = (char) ret;
+  }
+  while ((ret != '\n') && (ret != '\r') && (ret != ' '));
+
+  token_buf[i] = '\0';
+
+  return;
+}
+
+/*
+ *  get_data - takes first byte and converts into next pixel value,
+ *             taking as much bits as defined by bit-depth and
+ *             using the bit-depth to fill up a byte (0Ah -> AAh)
+ */
+
+png_uint_32 get_data (FILE *pnm_file, int depth)
+{
+  static int bits_left = 0;
+  static int old_value = 0;
+  static int mask = 0;
+  int i;
+  png_uint_32 ret_value;
+
+  if (mask == 0)
+    for (i = 0; i < depth; i++)
+      mask = (mask >> 1) | 0x80;
+
+  if (bits_left <= 0)
+  {
+    old_value = fgetc (pnm_file);
+    bits_left = 8;
+  }
+
+  ret_value = old_value & mask;
+  for (i = 1; i < (8 / depth); i++)
+    ret_value = ret_value || (ret_value >> depth);
+
+  old_value = (old_value << depth) & 0xFF;
+  bits_left -= depth;
+
+  return ret_value;
+}
+
+/*
+ *  get_value - takes first (numeric) string and converts into number,
+ *              using the bit-depth to fill up a byte (0Ah -> AAh)
+ */
+
+png_uint_32 get_value (FILE *pnm_file, int depth)
+{
+  static png_uint_32 mask = 0;
+  char token[16];
+  unsigned long ul_ret_value;
+  png_uint_32 ret_value;
+  int i = 0;
+
+  if (mask == 0)
+    for (i = 0; i < depth; i++)
+      mask = (mask << 1) | 0x01;
+
+  get_token (pnm_file, token, sizeof (token));
+  sscanf (token, "%lu", &ul_ret_value);
+  ret_value = (png_uint_32) ul_ret_value;
+
+  ret_value &= mask;
+
+  if (depth < 8)
+    for (i = 0; i < (8 / depth); i++)
+      ret_value = (ret_value << depth) || ret_value;
+
+  return ret_value;
+}
+
+/* end of source */
diff --git a/extern/libpng/contrib/pngminus/pnm2png.sh b/extern/libpng/contrib/pngminus/pnm2png.sh
new file mode 100755
index 0000000000..2ad17a608c
--- /dev/null
+++ b/extern/libpng/contrib/pngminus/pnm2png.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+# -- grayscale
+./pnm2png basn0g01.pgm basn0g01.png
+./pnm2png basn0g02.pgm basn0g02.png
+./pnm2png basn0g04.pgm basn0g04.png
+./pnm2png basn0g08.pgm basn0g08.png
+./pnm2png basn0g16.pgm basn0g16.png
+# -- full-color
+./pnm2png basn2c08.ppm basn2c08.png
+./pnm2png basn2c16.ppm basn2c16.png
+# -- paletted
+./pnm2png basn3p01.ppm basn3p01.png
+./pnm2png basn3p02.ppm basn3p02.png
+./pnm2png basn3p04.ppm basn3p04.png
+./pnm2png basn3p08.ppm basn3p08.png
+# -- gray with alpha-channel
+./pnm2png -alpha basn6a08.pgm basn4a08.pgm basn4a08.png
+./pnm2png -alpha basn6a16.pgm basn4a16.pgm basn4a16.png
+# -- color with alpha-channel
+./pnm2png -alpha basn6a08.pgm basn6a08.ppm basn6a08.png
+./pnm2png -alpha basn6a16.pgm basn6a16.ppm basn6a16.png
+# -- grayscale
+./pnm2png rawn0g01.pgm rawn0g01.png
+./pnm2png rawn0g02.pgm rawn0g02.png
+./pnm2png rawn0g04.pgm rawn0g04.png
+./pnm2png rawn0g08.pgm rawn0g08.png
+./pnm2png rawn0g16.pgm rawn0g16.png
+# -- full-color
+./pnm2png rawn2c08.ppm rawn2c08.png
+./pnm2png rawn2c16.ppm rawn2c16.png
+# -- paletted
+./pnm2png rawn3p01.ppm rawn3p01.png
+./pnm2png rawn3p02.ppm rawn3p02.png
+./pnm2png rawn3p04.ppm rawn3p04.png
+./pnm2png rawn3p08.ppm rawn3p08.png
+# -- gray with alpha-channel
+./pnm2png -alpha rawn6a08.pgm rawn4a08.pgm rawn4a08.png
+./pnm2png -alpha rawn6a16.pgm rawn4a16.pgm rawn4a16.png
+# -- color with alpha-channel
+./pnm2png -alpha rawn6a08.pgm rawn6a08.ppm rawn6a08.png
+./pnm2png -alpha rawn6a16.pgm rawn6a16.ppm rawn6a16.png
+
diff --git a/extern/libpng/contrib/pngsuite/README b/extern/libpng/contrib/pngsuite/README
new file mode 100644
index 0000000000..d236b02e7c
--- /dev/null
+++ b/extern/libpng/contrib/pngsuite/README
@@ -0,0 +1,107 @@
+
+pngsuite
+--------
+Copyright (c) Willem van Schaik, 1999, 2011, 2012
+Two images (ftbbn0g01.png and ftbbn0g02.png) are by Glenn Randers-Pehrson, 2012
+
+Permission to use, copy, modify, and distribute these images for any
+purpose and without fee is hereby granted.
+
+The 15 "bas*.png" images are part of the much larger PngSuite test-set of
+images, available for developers of PNG supporting software. The
+complete set, available at http:/www.schaik.com/pngsuite/, contains
+a variety of images to test interlacing, gamma settings, ancillary
+chunks, etc.
+
+The "ft*.png" images are "free/libre" replacements for the transparent
+corresponding t*.png images in the PngSuite.
+
+The "i*.png" images are the same images, but interlaced.
+
+The images in this directory represent the basic PNG color-types:
+grayscale (1-16 bit deep), full color (8 or 16 bit), paletted
+(1-8 bit) and grayscale or color images with alpha channel. You
+can use them to test the proper functioning of PNG software.
+
+    filename       depth type
+    ------------ ------ --------------
+    basn0g01.png   1-bit grayscale
+    basn0g02.png   2-bit grayscale
+    basn0g04.png   4-bit grayscale
+    basn0g08.png   8-bit grayscale
+    basn0g16.png  16-bit grayscale
+    basn2c08.png   8-bit truecolor
+    basn2c16.png  16-bit truecolor
+    basn3p01.png   1-bit paletted
+    basn3p02.png   2-bit paletted
+    basn3p04.png   4-bit paletted
+    basn3p08.png   8-bit paletted
+    basn4a08.png   8-bit gray with alpha
+    basn4a16.png  16-bit gray with alpha
+    basn6a08.png   8-bit RGBA
+    basn6a16.png  16-bit RGBA
+
+    ftbbn0g01.png  1-bit grayscale, black bKGD
+    ftbbn0g02.png  2-bit grayscale, black bKGD
+    ftbbn0g04.png  4-bit grayscale, black bKGD
+    ftbbn2c16.png 16-bit truecolor, black bKGD
+    ftbbn3p08.png  8-bit paletted, black bKGD
+    ftbgn2c16.png 16-bit truecolor, gray bKGD
+    ftbgn3p08.png  8-bit paletted, gray bKGD
+    ftbrn2c08.png  8-bit truecolor, red bKGD
+    ftbwn0g16.png 16-bit gray, white bKGD
+    ftbwn3p08.png  8-bit paletted, white bKGD
+    ftbyn3p08.png  8-bit paletted, yellow bKGD
+    ftp0n0g08.png  8-bit grayscale, opaque
+    ftp0n2c08.png  8-bit truecolor, opaque
+    ftp0n3p08.png  8-bit paletted, opaque
+    ftp1n3p08.png  8-bit paletted, no bKGD
+
+Here is the correct result of typing "pngtest -m bas*.png" in
+this directory:
+
+Testing basn0g01.png: PASS (524 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g02.png: PASS (448 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g04.png: PASS (520 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g08.png: PASS (3 zero samples)
+ Filter 1 was used 9 times
+ Filter 4 was used 23 times
+Testing basn0g16.png: PASS (1 zero samples)
+ Filter 1 was used 1 times
+ Filter 2 was used 31 times
+Testing basn2c08.png: PASS (6 zero samples)
+ Filter 1 was used 5 times
+ Filter 4 was used 27 times
+Testing basn2c16.png: PASS (592 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn3p01.png: PASS (512 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p02.png: PASS (448 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p04.png: PASS (544 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p08.png: PASS (4 zero samples)
+ Filter 0 was used 32 times
+Testing basn4a08.png: PASS (32 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn4a16.png: PASS (64 zero samples)
+ Filter 0 was used 1 times
+ Filter 1 was used 2 times
+ Filter 2 was used 1 times
+ Filter 4 was used 28 times
+Testing basn6a08.png: PASS (160 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn6a16.png: PASS (1072 zero samples)
+ Filter 1 was used 4 times
+ Filter 4 was used 28 times
+libpng passes test
+
+Willem van Schaik
+<willem at schaik.com>
+October 1999
diff --git a/extern/libpng/contrib/pngsuite/bad_interlace_conversions.txt b/extern/libpng/contrib/pngsuite/bad_interlace_conversions.txt
new file mode 100644
index 0000000000..8afbde7901
--- /dev/null
+++ b/extern/libpng/contrib/pngsuite/bad_interlace_conversions.txt
@@ -0,0 +1,9 @@
+basn0g01.png
+basn0g02.png
+basn0g04.png
+basn3p01.png
+basn3p02.png
+basn3p04.png
+ftbbn0g01.png
+ftbbn0g02.png
+ftbbn0g04.png
diff --git a/extern/libpng/contrib/pngsuite/basn0g01.png b/extern/libpng/contrib/pngsuite/basn0g01.png
new file mode 100644
index 0000000000000000000000000000000000000000..e31e1c7a635b50e22b6d02ab8ba21f8099b39faa
GIT binary patch
literal 164
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk~Bp9L@-6Me%OS+@4BLidG0>c;6;z7cmE{-7_
zGj-2w<YYGBVZHeJ63Zqp1@0=7{0X8qO$U3q5?$E?KR)QvU-jzJl9rrvD^-Kpo(G$R
z3q2Ctq`2Q(%~sl}SXDKy`_`s;`B|q7GWF(aCg#1&H%R@kUtXZyQ-A4{ifEAap00i_
I>zopr084i?r2qf`

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn0g02.png b/extern/libpng/contrib/pngsuite/basn0g02.png
new file mode 100644
index 0000000000000000000000000000000000000000..68809dd8fc0993ddebce8aa9c7bf9bbecbd36cfc
GIT binary patch
literal 104
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk`Bp75C+I9jdmUKs7M+U~W1%@xC#RK{Bo-U3d
y5>t~CIAXub_k1+y2sp$L+}6)%%qgEdVJADoUeEf*_U-^?kP)7)elF{r5}E*i=NeZ4

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn0g04.png b/extern/libpng/contrib/pngsuite/basn0g04.png
new file mode 100644
index 0000000000000000000000000000000000000000..6fa089cb8a4ba0e8421ea05d33676856f0cac93c
GIT binary patch
literal 145
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk^Bp4<?JfR7sSkfJR9T^zg78t&m77yfmc)B=-
zXiQ8_NDvSS2{JM(E9B($_14x;S8!&Sdi$bdAA?r;GoK=sfSs$uCMq|ay1RF_3}eW<
qnZ{2z78Jd|r|Qly_4hkjNhSt)k#~&ox|xn3yF6X}T-G@yGywpLM=Kuy

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn0g08.png b/extern/libpng/contrib/pngsuite/basn0g08.png
new file mode 100644
index 0000000000000000000000000000000000000000..bf522eef0018ae60539ee1b50e98d97906101f2a
GIT binary patch
literal 138
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk@BpAX3RW*PVOS+@4BLidG0>c;6;(>fePZ!4!
zi{9jv1QiAmjuV@CSXq1cIW&KKm$y%-G>{Q7I3+kCJ!Mg43=bP?PydHg|Nfu<(f+K^
hPy#6PU}|a#3q!!ue}#oBxm7@xc)I$ztaD0e0szfSD4qZS

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn0g16.png b/extern/libpng/contrib/pngsuite/basn0g16.png
new file mode 100644
index 0000000000000000000000000000000000000000..318ebcadf4fd0b64fb9b824e81c0cc8e3dfd2d82
GIT binary patch
literal 167
zcmeAS@N?(olHy`uVBq!ia0vp^3Lq>1BpBEle`W(ImUKs7M+U~W1%@xC#RK_qo-U3d
z9-UV&8FC#k;BgMLjDBB#?9PJ82Q;dUu4=I?zS(bY(Xf0+xUg{Y0;{G3S&o?ucbmRB
zoML$)c8ASL&0+fj+X+UDyI8k3PT;(to58=tC&50S{f++@NsIIK3}QFDZ^ZA8J8=o*
N0#8>zmvv4FO#l#XIHLdn

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn2c08.png b/extern/libpng/contrib/pngsuite/basn2c08.png
new file mode 100644
index 0000000000000000000000000000000000000000..21d2f91a868fc637fdae4fba6c87bfd09b158815
GIT binary patch
literal 145
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnE1SJ1Ryj={WSkfJR9T^zg78t&m77yfmc)B=-
zcyzwKdXSUBfQQMU_07b;+lz#)U9`U}{BiD~_7+|i>jo~7A2JKxKB@JoaA;)W_iC3v
r)WR;J@nJ!Uh4M;=#@z+wiw`h1ZTuN$cYX2<pqUJwu6{1-oD!M<;Mp+-

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn2c16.png b/extern/libpng/contrib/pngsuite/basn2c16.png
new file mode 100644
index 0000000000000000000000000000000000000000..1bd4a4d0e2c2c6dd8a2e63a63b26f166b8ef5353
GIT binary patch
literal 302
zcmV+}0nz@6P)<h;3K|Lk000e1NJLTq001BW001Bm0ssI2tcWq-00004XF*Lt00D-e
zG3b_G0002xNkl<ZScTP=!3u*g5JacoL4V7BxBad5mL3KJl7=Q`lgxS;hDGE()}W6N
zLI6H5;F|Aba&vwdJts3?&f@c0ceeuT&U7enqBEEC?ecJ4(E(udvVmXd?D7J6bf&Pt
zKXj(#87M>NTx<h1=<G5A_2^6ifxGC;sb`=Ko%2Z>us~-YE?|ew94KIo9tHTv?hhRR
zwrA%J^h9UxCeR<fo4_daC}8&;7>myPjW#d?oxNFL9(uFDZ1gBle+D$rIj`J+5;}Xa
zfF63WfGT<v$e#gibj~vy@PN*q2>3xy1iYa$zve>zUQQss#Q*>R07*qoM6N<$g1`fR
ASpWb4

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn3p01.png b/extern/libpng/contrib/pngsuite/basn3p01.png
new file mode 100644
index 0000000000000000000000000000000000000000..a21db5977462c4c0985a0ca1ac2d67ec572d3d17
GIT binary patch
literal 112
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnL3?x0byx0z;SkfJR9T^zg78t&m77ygJ1^9%x
zzWcAFl=eSI>XI5zMAXy8F@$4g@&k4zHj_up0t<whm+&#{mbX7R;pmxWpaKR@S3j3^
HP6<r_p<o@S

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn3p02.png b/extern/libpng/contrib/pngsuite/basn3p02.png
new file mode 100644
index 0000000000000000000000000000000000000000..1d0ab6197cc8c4dd61e4440cbe98b2149eeafafb
GIT binary patch
literal 146
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnH3?%tPCZz)@mUKs7M+U~W1%@xC#RK`w#ZI0f
zjEsymdgV<(E>D0@h%3W?AY}Lt#0>va?X`CSX(dk=#}J9B$v@<GbuqR`elYlO@}R`(
l1v)i6D=z*2A<=xsmSL}FePgcHsoy}=44$rjF6*2UngFeOD%1b~

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn3p04.png b/extern/libpng/contrib/pngsuite/basn3p04.png
new file mode 100644
index 0000000000000000000000000000000000000000..6dc6eac83f3cf984a4d121e27a8e60454117e12c
GIT binary patch
literal 216
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnF3?v&v(vJfvmUKs7M+U~W1%@xC#RK`w#ZI0f
zEG#VLKejFga&-fILR^&?{xkgl-@))-=|2O*%>Vz>816FsF9(VN75txh7sS~8e>Vez
z3y|e<X@loppt!rIi(`n!#N-z*ICyP~)2^=iRFwR<{C(QF6a{C7soEMIeGFRHkG9G%
zhP=DG`w7Q_Ldg??4o|f-Cn`6b^7U4BXPCOX+FX)};lYtt7kN|r4*-p1@O1TaS?83{
F1OO|$P0RoQ

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn3p08.png b/extern/libpng/contrib/pngsuite/basn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..0e07f483c0edad13e60e0d475c33a7ca5b8919ba
GIT binary patch
literal 1286
zcmWku4NMkw7=I2$3}y17=z>5zLEEca@?OO&kPSTILuD+yid<Q#FBz^`v>i?7W^Q<V
zIS@4tAr;W@A_~TqUM#;}3_1KtXTxr_B{JH)rI15Q@9Fox&)&QL{{R2;{63y%S5;J)
z8x<KBNkmckdGhOcCx!kqr{O7gRA0nvdTG|WED|b@rj8%lNHmR#)~?SHWqQbt%Bsce
ziKKLuL=h|Y5EjH;N`Mgo7FdiSn|YXZS!Plck;t-GmPuj7vPg;}zGpkkqinHl%Pb>F
z0=7twg95}IGPB`0p){BIDdQnXEGb?R1lBYr!w>|Li8PIP)G{}a$YQ`p%(`K)LO3UD
z6M@=IHq>+iwp~U6B7p@ho9?k)W)s^cNfJ5alp|5o3vi!RBHkmgX}UWIuw)VII#g=d
z$04w7jssURBxceP_z6C6HW{SZU_uGkHHZpyqy!k&kY2+c1*akQFoehhD3_nQ9ng;b
z0F#8v3ad!gP>4LFqCR|KhXmq>PACHhpyFVSOH8CTvPiZqN$iqqnyfQJ&?bvale$n1
zTv^)Th9oKqsKIPjfKCD1Cd3{VRFz%0i$*94z+D%LEeH_80824wD<EX~FiU(BniO4!
zA7qm0RfsLC57ZCC3DY1WTccuw7}f(2Y%mutuw>Gaq4ThALK_0kH^LL!W!ET%TWXjP
zf+UjIVU&gj2dkjg55o;~Er9W|;Xj52QG;=_Fb4{JL{~@@LhLOJ3noJ*c>^l+tMCGO
zCYz+H<xYr*gusT%U}V4yNF|R*Vi3J`9LR!U1igI$4|yUz#2$~0IY8@K6EHXupWb)l
z12nrQU(Q<ZuZubtK{KaE)7jk4+PuxnGNfm=l)bg3^zYc}Yu`_Ky)S;)6!p!vq2JqU
zD_aki_<E;)`myQ!)V#4b|Ly(qgq@N&D$FR~^Hu-A=iPI+=3QF7_O3U>e>Pl<|Ld_f
zqkm1#%jMM-%}evv+<)~($raC^D<>wy%g2N5PX<@DWeyA$O75|=jlHcE2YqXoq<-r^
zSF~%<yLZB?@6Y}3WUhKEdR^zx^4q^O#rBn^T(7Llyn1z8dvsJuUe}4|7q1+8<Iwiz
zk>HYo3ID?48vDt>55dBr2eB{o9GWV*`fG5Jx3PvhgDLYTpZ#Qi+|CPMFK>V8kJOfm
z#*Z=w{NC;LVI4^y_wGIZ+0l95T|3etXWUAydp~nc!u}QYkLn)pJU@Hlx;E!j?tzqu
zY2yX+->z>?3??Uzz4BVazO+Xz%j8eHAEZy_UHonH-GsLIpF6E1$sG&stX%!v*c@Yf
zL&of5NeNZAyW0FGPYv%K9`*NV3kUPJUh!4N^d%dUzFDUR&e(zJm#a=^UXXnc(yA(I
z-;o2p70nAqE-$V<zA9DQ_0J;VOk=~+k?fZCS*@3>851jZH`@`r<K1ZCKu_pPNBKF0
Ka(DK7U;GbG9AWPO

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn4a08.png b/extern/libpng/contrib/pngsuite/basn4a08.png
new file mode 100644
index 0000000000000000000000000000000000000000..3bb0dd06b510cb42855ce91f1600540f4503ea34
GIT binary patch
literal 126
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnE0wix1Z>k4UEa{HEjtq=#3k+XOiwE*eJzX3_
zJUWyAoIh}Yv2{*{iJ{UQo%@m+%sTdM`xqA|8c4B)7$%qqxF2rNV(Vdhlpzstn1SKG
XmO|}<{e=-g0~kDA{an^LB{Ts5zRx3;

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn4a16.png b/extern/libpng/contrib/pngsuite/basn4a16.png
new file mode 100644
index 0000000000000000000000000000000000000000..6dbee9fbdb93f3535be23326a52fb4d3ac60711e
GIT binary patch
literal 2206
zcmV;P2x0e$P)<h;3K|Lk000e1NJLTq001BW001Bm1ONa4iQ{fO00004XF*Lt00D-e
zG3b_G000P8Nkl<ZScS!xUuawB8ODE>kEEkx>-b1@Qb$y-ohUek5*oTfx-A#6y^c`Q
zE+sS)yU66wLTO83iFXm5i(N>*n3Idp^rFd-7Fe(v0)u8Hg(Rko(t3o_;+1WoY3fR?
z;u%**k?mvsIhJ?vei@;3*EJZKPsh^xKJW8B&+`FbWnox{J*QyQf)~!hu>m;#N5~Gr
z*+0X@UGUyz_~;4v=U?IOURb{_zjyb_*+);vGZ%Ns|73^cGmZ_&XO3F(9mBeOCxB*U
zp=MjTt{LzZp}PWF5dym*a0v7!gx-ecb!ZpC(_mu+I?n=c$cJ>2a^`8!UXW*-DOjHb
z_YkaIf>i_R6{x46R)AUxtZXgQHLOFeVC9@tBpY?%Ar~H6|39xka0c+50pEqb_xeL;
z>a}V>WX7?rbS<M<S?RpXg{om?eJ7zi1OC$x$bfzlLK*1EKr;jF40tD@lYz~QLLdiT
z4%$=D%t0duZVuLRurdYp9Mp2)<e)kQQMYDCQeb95i)00Mp9{W|usjvX`sP3z1OJzx
zUxd&i^o&8ngVu-OoraCWu=$7-uyI(<S|7?Y?o+V#I;`A)d&j`p0@Z`CJPZ9N9XsMe
z-wc>B#R07d+ApMY-yAH>T3O$tpzVWT4D`KV9D#5e8fT$B0UQ0W`4d&ZJhZPsBM<Ap
zgVh4m*P!+<sJ3AFHZ0A;*3p_B&45(}^Ihn@k3e8I_<ts_Yh&Ph6c!7StnUo?KY-v0
z7$pdwfb}{w-vVz1Hm^zn-iVy7`(gD2)Jx#J0Lw>V$%MrM45S^qKLL>pn6E&%2tD%(
zfxsaMlx61rFQs$e8K{_6R*OS$5R5?x4}vuajX`MdfzF^5&@Mrv1ZyRz{~eqXESKOv
zC8(4kR<GGxKZ9rh`gTD0Tj-eq<1Y#Uy$SjrA)J0uVE2CjS{zE{NLJH8*P*u;EDKy0
zS}o{wq<~gS&gyljR$*xgDitV|VKDC457(i80;~#ze+@lpFp3bGRtSXNhR`lyduUN+
z9$b;mH4W~3Wo7;Q!8i)m1Z+75jZx_QMha-;VPzJo1z5~OIS+Sk!1m#q9g9K#3PjRi
z&dD|zUqYw|!TTI&UI*h-d9!Cs2xpW8c3lVmez=v7WP^`EUk$cw19ud>Q&NCC3e`!t
zTZ4s<;Z`0-CLBBdHEi7qkvf<Y(Axt>2J|EZXCOGP5NH>n6_-74c*6GZ37L6suXG-K
z4CW`TtWk#kGCXQS`*SIvW<w<oUwi`dao9awvxlCBfeR3gg1G{{X$buR^k*RW4+s>&
ze;)x)gZ678GOZ6~)z<4mILi{)`)Xj6VJ;rYMiMZbfJQ<JSiA=Rz72D?VQ<;7cRmT*
zEQqGTG@+*sp)}}Y5coOxp9g;tG*2P0F#;RcMB%*CvgggWgzc^?GvBgJI*%ma>TN3<
z-w!`MDg}Ig4z9ir2NE@VR~cfbAbJ<VLtq%7e+R)=!G936<DlJy?iuL5r4Z;m3mrq`
zb>pyzjJG1I)@lji+);sjI05nfaPE90J3cN2oI4LMzvS4Dmtmj`)-)Kipf5lm0R9Eg
z($KwIiQO+n{(bK$1b72BlcMdLkBGu;UX?xXbcF5RDVcdAA)Swp!;446R4=_#v$t=D
zz6+p#1O8K>O@QxD;PZj64qX$_)dyW8(DgUyDgtM~$B+D@)ok(ejv=nLaagq78xe(T
zwPerTQDOVyHJSOj^U^uMi$~z)m*DX-4D18zgc`veH3Ac~yc)q}HG(AgY|tG00TSjE
z39l#;mV|^Wv$E%vxUl`|`!e(G+og+_Uy_0jBw$w@Vv`WfKS07T1Ph9UIYq+fpnH!(
z;D2j4rPeSn#<EsY@>&p)`Qj5<wF8No{dies4$}F71YErhP8@dr>U(Rr4MKU)UxPqX
ztzk;7p<_#oYK2so@RX&V5M!xUMP3&^7LnOocI;h>?fN%Tz`#D~+=;_n9NcNR_n;7s
zK<_CC-2h!vLX-smkV2q&9h#r2B=eN=^OCsQ(voQVt-L7Q&L?Hht!ZI9$joDt(z!bg
z^OMk=0QYNHU4=*(%mVbj1IA4y#YrW_j;#XZ?^TR?UBZO(f>>&$BE~W@;n+h@D`@Wu
z$+QV6z?hYpZ?mNH=7bd79)?B(Toc^9GNU(@8Kod-D+Jaj!40VlcSDlQ@=@{gQdwLr
z{<VTME#%S{WY0m^9v+hS1};eF?P0j{6?h&r!_X{1qXOZavg0I#?r(v62-eCHAnzTM
z7`0?dm>7&Zb}S~Y7L5w23`5q-r&J^mkTcViXI59GbI+3oJQLb^Xa=CM0~+5#BMC-O
zA+UA{R^F8K>THn=w^)!Q^Kf1Hd0kwsr!Ly=Ul4@@*>gQCY&S<_=B_E7dnQy&=%m3*
zDCd0zS}ADFD+E>zs2dWUs|O`O4x}A>>t~W=B5CF4X>qmStD@~)iUV3+_B@mqwwnc+
zd9xs$chb^OXB50E(5^x|39aW80`&^qb0xPgtMuBRkPK&4ggm`H%Fo9{P`Y=EwuAib
zKPY=1x*=>g=Va#1fOOs&mBu<b*!V4YN$_F{fqDv@8M!p{pLFbKM$&8F4wd0DD#<(}
zey$xCSL+&41zZ+|3p8cVjhn*ua8734E=uQ}94t>k$A(S{Hf;FuuV#)d7sbeoV@Fcz
z#`3Pp?K3L97A3<4ijriy)kU_eC<XYEqV4{aC|ocpdu}9!?X8r|+)GO5n={~~U^A;Y
zU}b9=D=l|5GbT5do_Wdbp=n94!Eu%0JV`RX_kc6109zT0C-NE`7m*3svTCh)A)FTz
g*gI+Y@|q3*1t0>)4|}U(UH||907*qoM6N<$f-(OD1poj5

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn6a08.png b/extern/libpng/contrib/pngsuite/basn6a08.png
new file mode 100644
index 0000000000000000000000000000000000000000..61062308548bc3a5255e3e8dbb7f97932f00eb1c
GIT binary patch
literal 184
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnE1|*BCs=fdzmUKs7M+U~W1%@xC#RK{Io-U3d
z5v^~p8FDok@VGrxPs#9K_}xB~rC;&L-J`A*vOzBbH2%o@YTWE%G>EINoAZB{akFeG
zt2^^4wiQ2lBNnjxnaU~EHpDcAJeJ<z#2<4<kD*ebW77Xe3mDB7R6DRwu@PXo$sieE
f=1|Wl{edA!L2Aym{+H=Ms~J39{an^LB{Ts5#DqLo

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/basn6a16.png b/extern/libpng/contrib/pngsuite/basn6a16.png
new file mode 100644
index 0000000000000000000000000000000000000000..a9bf3cb461231de29905eaa02f3a8a66f9fc5477
GIT binary patch
literal 3435
zcmZu!c{tPy7yiwHA^TDknhJAO5;JmTFJcJU8M34%B>R?S{LDp`Fk}h0vV{=c>|`0F
zY}t2XhO#pw*@@4+-}ija_s93gIp?4AJnwVP`=0Zh6Lm*li-YYn8vp<tSZxiX<B0s*
zxS5arg{8cz;{boCuBQ$_A~IzbQf!a&&SN#yO&mihX|^uHBR*{*KjX`EJ@u~4;^K7S
znZ-}x2|!2r#AusQ6tq*1JMtvb@`}-*EUt-U)gGM$wek3M?{Wn*u05Llx2t!WJfnfi
z*&A7X5|P#el2N}!iKN3dU<8r|CRs$6RIMxBPMJPfZc*@iYif##R~J1={rXbTkM2jW
zpAVXUmYnCr)*EyRNatG}eNi2}f3`FDlHQr4b0KIdIQ7?@MDW@Xd2WtcN<E7U8Q@B1
z;46o2QRJ-FF00|Mpjmc3aVc%yx39|V$P<5fkhLdT8c%s|j`z*KbYsP-nhfr*7-1M=
z**hcG4-NP?2^$+yj6jVaB)hdon)Os+Q_M)n*!c!YuPhvKP8%=mDyvp_jdy9xs1ja3
z>unKbAURdar&!F_@9SoS%FU_nL5v4bhxdo;qYV}(%9Z85QFC@Q_IDD58Vx)&SPd#1
z&_z21b`BlfZb@Z16}%Yv2Xg?CHRMe7qkJ)iJY&NQ*3GZeU+ur74iHv1P36E6yN%N5
zpV$8~7z8Rae`?A#-PAcaas4$5zYproUQo8+k=bWG?@3hw>tAT`15|X+#pzBR<JY!n
z@~!3)iYJD6F`s2~fbPC7LAABQBa;bEZSPfF#@)xL!MbbSkHIO=+5*2LT@-F4%BC-h
zkjs~0c=Mp{^gT0<tkslzg{x6EpQ97VPm`-{Sc-IZYI)<5=ZG}Vn4R_6l29D$Y2z_y
zu@G{UX3K2xa$$5B5Bk5>*EFaZTfujS2W+R%rAX5GszY`8KG_1tm1wxz^bYuH^_iu1
z#`8Dkd|UXn0~66IH5Y)%1^wg@FJA3z<g-qfYfZ)1vJ{D1ST3x<9QE-L5F&MF8wPLO
zIub@6gjSVOfP8)*<8))!Yju`hS+5im6`}RB-x-6zb+Y@i6yG6A-Mn<Qo;bXJJzX^X
zyQzp)kGua)ipSxNsO8P|M#QkHeCx87*C!ln3WL7Kp2_o21hngr2H>9$T7YRh1FE(o
z&iHoiEcavc!3({fssSC{c=<<H1_J{E0+6=)8^yO0XoX{i9O^xM-okR=8)j`EZ%T)K
zK`V?Lq0;!V7~^v?MrtM|M%m9q_r3MvMQHKLsuD+U*MlYbGf3edZIEWYDPcALuM<<1
zu=AS`iA<qJ*U1cpS$tWB+^MDAAQi6TYOo@j_1?xFnti6_zJ(Cq1;@6c<)0k&Hb&Ma
z#c_f&L(UCVX2byHRG7tE?~{;pxBFWF{MVrXIMg0z54v}qVTvTs2^`3D_laQ80s11U
zybZZD5*vulpLFppo4XNAnOL5R2vWG7A7*0$Tj+SA(>uH$6|lJ`Cw^#7+?<C$8fV;!
z*@+cdZaXGIsn3hs?nzD2iA>9Oeh5*sk;TrZA_s<KS2~MK_mYQb7}S*lt$g}*5SP0r
zF4*4|lZSNg_<Wn{TEt{fifiuJHU|IlU66X}<qT~0R~!viP0o0v>xq|m5T=dEMGV0i
z^PYDhxn{(1ZN~3SMiq)&y^i<G0J7l`qG{=-$UG$bDa97hNSzFXWE;~}!0OMt!pPl+
z`)(6K;Jf@$NBRGSl$8GmlA$^nf>@u;6U{BWs8VI#ZOVtSIoPu#Uy>G@F^}60slpM%
z4fg4f0@c(&o=lnNB5(wh%7VCL!-EVW2Z|!o{aAn*D%&65S@(Uw9aQtxwD)dfkbS0D
zN4fECZ9%?vJvB6eQZ4WGA92VxeEjiXK}uR*cR55gZ_cQBgwFlZzlpoCI^<hBj<w`<
zy%$QYUb+hC-FdL34$>@-;A(;$?Ag&)@JLm6Q6RE$C5WB$XVqD_cH4>}=w0RmK|UFq
zqT&JFo{xshQhkO07xrmHL<G{dAqdMbW6D>>wC3kOr5B~p#zX7$p_c_}QIK>i^mAbP
z(RxI|(i~*Q0#6E}svt<kWp03&ZAAzZN#C*sSQNKUa{Vv|^s^QPv#jZ9#_r#Gcc#y|
zJR{+%L}CVrKdAL^n@h^*b{)1ZU=V_~zx7%Xg5u8+=DI0$&f*1TKc9fK&xiV8fy9N@
z(B}~CTPq&mM)9VgT6zb2f3zu_rYPIuJ#`wei-xN070L$a3LPf7Rqg^N6BX-dWvEnz
zYk7+Ee@WalYbf})N*@hA2&2?}{m4q{(d9Z)b2noD?ZWT*GY^3kPb27iQQaP>MT(M}
zh+aH!wG#=NVm~3Dv%@S5-kh)W{c#dFYEqq2IfIFM+s<@5JzKFU(kzGaEKDY05{~)y
z&m>r1+fS3X-!8#9ZC}|9nR|zJTO|nFEi^1Tfpt@Ll^mIY?oP}|^w=aDO<B^-y~t3s
z$>Tn=uec<16y1Ij2viXQ-skm0LAjJTsD=F!#DdRhpGW%{rtjIu<QM4&UAdPEhpn=Q
z{w>duzuQ<{wdf>RTZ$_*JNG)(wu0^Ec6<FISH7z7Y3Qi``V0Y7^y@&>FbT<6xqSx?
z_!3zIUUfCS)6fLwA!%9Yvs}RFb1bBZaM#FX`Dt@6LHtQA1;AaBd4qVKP{nI32V#wJ
z&Xh<q3glMv3+*eA)fvL5{|B>LUx0p{l^jo|vK~SZ`ptJ4<ci1df8=h|`_pDZW2Ir3
zc{B_N-u@C<b841jjNHZ!GCJ8mI!tc^ALm<60h675%m6BylEFc9iIWCKvG=M*V4N52
zjsK9T0S$L0Wa`CL(SPISP&AsY6*zxU-=&ni4p;PRHiFcmKB24Y*JGS}l@Yq={`oyi
z)>mne>h=EQ)IBapSiJu{K;#J#&J6T*;znj93+*IlB6?-&YMGi|#xn!fR)W?0*~Y-v
zJb%t6l>}jz9_AsI@@RuRW(OUfTdY%wuhTG}3Ve9pnfH+Qw4C3B8)Pv=6}W4d99_e^
z#9AT03q=Y1K=%(%UJPCeUhitoH`-hON*?knX(%Hos$uAK073oP!1*Xq-mClxyor$@
z<Qr7JCjc<`>}heD;=s0m{le|mRTbo3Wp+E$278tBRf$HlP|fM)?++96CPyL1+wsjf
zVk53I^h-S=*7nAhx<|s)bJ8<VnbTJ&F|j<nRK1cj_D?0_5Kbb`+UIkpS^QWg1#4tJ
z&>w@jBPCFcgym*E9ryTcW-vs2fn~wpR?z?3`C&?_rYej3k<^}V2IPiv-8;{mgi2hH
ztlSGT$s1@-?Cm1cFWbX9F{sRW<Ym(=MXp$(FPu7y9jXvRfk~y@hvb0UghfmDBJSBY
z25ZGi12019mKLYO)|A&8II+^BrUk==a(yST_a@%w!E*-aHedmL4#>v(?cibljVBrb
znh0Bb)h@WE8=d#nxg!?mgZ_jv{v*Mtb>{rWq@mQ%GO4pYbYY3NhtwS%vk@F6@Cv0q
z;32kUm2%K;GCpIm7nY^O2baB-b57D+>*@DbC6}<(k6UKuV_t7>0Ad1l2vQK9%E7Iu
z&(5t^!vq|;yR##&(?y9Bxh>PK;x24md0z_`OZ&EXN0znDnHMLgT<SGV3huKE!!yZh
zBI1Z48uud1lP(gi!oKg@oee98n(-9pkVGMMP%O_Rn}+6EocfOP+9huOb6))ERcA_}
zzC26G0pfmeqzHd^`o`D^;75`%5ZS5E+C&w$1|qi=R2|Vxh1bbu5AJ^Z__j=^#>0vE
z_yTz|TbH$rwir9{GXE3${#InnMxfp1xrN`krccn6rI*N0fJ7fVs@lf)c+k@Bj%@7x
zn2jh^(!=IcnGPq-s=mA+pAQRc3WQ}3(CFdc(eD`%-gjE}`d9j0woiiIO||T#+v6=j
zd(Vm%BvEfmcrs6v+tJ!B*r>Oomj6Yn^vw~qcjX^|m%*OM51be;(%YN8T!+aSl}jzO
z!y8LjI?!s%Jnta+*LWjuuoDMp8d{FnQWAsFx^5}~^aqjGKt--Tz&i+DWSigz|HVB-
z?p9v``EK^JY(aBjc6TFYcV~A?IDo|@Q%5w24{w**chBHLlrK0ny!nC(PsT1>Hqnih
z{Bkl=fi=xu0ZFjuFh^xM2sQ&sXR~!_Q<r2rcF&8=lL>d=m2&L2Axw6>g3OQD`iWxG
zSjeA<d*&T7hR`V#FG+DKwVGd#sCe1=la!hglRhL7`~K;sGLuCbE^R5v#l0)h+oFto
zWXg4wiDNf%@VA@3<z~)t>Ufi`M4@n+JdMglmRaM{EnaIoCk%7r&sK1kSNCR{49-Ta
zj?6y#Lz!(+99uqME>10f)qmtbigTu-hI=Xb4zcPc{eH2<Ss@m4ys2bK^>y_7vv*s(
z*^3PwpUJg-5C=DiVuy>>a!|8$e5K?M)}J02FLf0O{QRMti|gU9y<b_IZm!I`n3S>M
zpsH)mY4<C4uiUSU5^`;8gWq=>IMnhuI<uzwV05L0!*0Un_<I7dn)(_gH|&W20{+#9
AwEzGB

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbbn0g01.png b/extern/libpng/contrib/pngsuite/ftbbn0g01.png
new file mode 100644
index 0000000000000000000000000000000000000000..ba746ffb2f5e834db9e061b213a9c8fb38a80707
GIT binary patch
literal 176
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk~Bp9L@-6Me%Q%R6tFatx`<g*qaUXr)F3j@Qd
zUS%VY5>FS$5RU7~2?v;79du#tuwYQ>a&%Fgu_O4vfdD?GSMM7;DjgQN$$5yJ5Wm9E
z+5bP`$n$a@o=x-l8#oqN8qI&s(D|rVAxZ9n%ri5ALOz#2%tAd1O%M6amNPJH^j176
T`tP7S&>99$S3j3^P6<r_yB0Pc

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbbn0g02.png b/extern/libpng/contrib/pngsuite/ftbbn0g02.png
new file mode 100644
index 0000000000000000000000000000000000000000..3d83bd6900baf4866450babb403ea2b0cbefc02e
GIT binary patch
literal 197
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk`Bp75C+I9jdmUKs7M+SzC{oH>NS%G|}k|4ie
z28Oc9XDvXyByV>Y28LC=%0@t5f~SjPh{WaI^M+gp3^-T=3csiv4Q}hPY)zR|f6C0w
zxJ2XcWoMTCF7}HoGFZJm8u^!HI&jaJ_kuGy=R#8y15dr<o%y=+ZlsGXVw7GI?T}ir
p==VB>w_Xvx6CN;KWxv0ZanUbL``{xlqk(oYc)I$ztaD0e0sz+MK9T?c

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbbn0g04.png b/extern/libpng/contrib/pngsuite/ftbbn0g04.png
new file mode 100644
index 0000000000000000000000000000000000000000..39a7050d27af28f3bcb7bfc6b071cae91f8c091b
GIT binary patch
literal 429
zcmV;e0aE^nP)<h;3K|Lk000e1NJLTq001BW001Ba00000li|oI00004XF*Lt00D-e
zG3b_G00002bW%=J01xIY(5V0b00Lr5M??Sss*NKu0003<Nkl<ZD3Nv1F;Buk6u@yl
zf=5|QT&^T8CMJcdlS^9}9W3QS9GLE%Ca&~ga-tj)lfotX85|wmBrdWtn6R2Suxioj
zU2POdc-#G^ckiG3UYXoFc$qCha!)I_3-A`vl3A>eGf1AoYPn=%bN?oV&q3&xZP#{-
zd#wGeV8okcyH@o)cboHb1rrf^jB^?sG2T2?@G1n)CJc@hyhCf)&E8%^0~1oF;v>7S
z;6sBJiji@r0Yq=mmR;)Ojr>$W46R-Sau7HO7xZFtI1{|4z%-nLbW<Q*PUN+ZZM>=B
z3o0EAC)h$;8WIR1rohQ#w444G0#1m$Dj66xet|L#R>4C36e7xMM0T)(aSAa2XfV)D
zcEU#my$(kCaRx~QL^LgQ_;=)3gHxFOXBZJd{maEJLqY3H<>rDuET^1Yth7z0>+1gi
X<C0d-TPjWW00000NkvXXu0mjfX5*|Z

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbbn2c16.png b/extern/libpng/contrib/pngsuite/ftbbn2c16.png
new file mode 100644
index 0000000000000000000000000000000000000000..dd3168e5c864a81f3284856f2b00fd1e52eb312e
GIT binary patch
literal 2041
zcmV<V2L||wP)<h;3K|Lk000e1NJLTq001BW001Bm0ssI2tcWq-00004XF*Lt00D-e
zG3b_G00006bW%=J|NsC0|Nox7OELfe00v@9M??Ss00960M`fvi000M!Nkl<ZScTQt
z3rrhj902g|lt(c5h;B@c8Wto`5z*MhVpEu6z!sLFwWDPtp>{l69U>r1pj4E?y3$fw
z3LPC~5Eu?Ow>bx*PBc1kWIARHF=os}<8u$TxvBB}f1oy5P`W{kzl6)>j^6kGfA2f-
z`~RHyuLHPP3zER+<N!HM7NQh34+(rt_L4eMKuSs;26c6JfUR58z}T1z96L4zF1}nA
zasnsGD6x?uVlw4{>gr^$apTp%;SiD#R;vJ2Rd{S@z+-2p1bTZD!RV+NOifLIU&uTs
zaE81?yrhgg@q`IfRXqTjnr;GKFNW3KjX}4zVxZ4FgXd*s(ZFE9a5b7MKz26X)$9LG
z&+U!?)zyVy3pqr7Bq1d50~sfsq>_}A+FGpRrY7tX9#13)1Tctg+c1b-yYP7603Ht=
z!sEyY-tFzh#G0G016J#8z+$-u)Ys$P_ICWwmKHpkOd3!^xI`}9Pq-4f{bx<!Ah8hs
z@l!$C+mpa6uVBG1zl=o=4dMBY9azV0ZTAAVI~$CQ#DU4lOTcHJ;r~oe<Nts46&^qN
zWF|?t{_3lEZZ>0*+^SE_VlClnoi%|Y#7Z`h22w+;)<?kbFxKC;Z8rjkV+B~h9t)^C
zPklWGG&p!4n4F9S$B$nHzWD|do|wRK(%*jzsHxF`^Pf;kR+ERxJ~C?p-x3bGo?s$Y
ztCR4M<@R}c!EnnP$s;72WRWk)tO@X-u~-@!ESC8Aj*j^Fu(1CAu(0IhzP{vSyS=T=
zZugKD@*JtTAk{%QbnYZMBsgdl(UX4}#B3vxq&<5i=%w$zi+%OX8JstUhV*(j;Tfre
zw2>xK8=@ykF38Wv&SbTQ0gnee+4}W(MW;&#YW1^ZP6=>`(a|rw5FIVVzI~X$*|S2#
z#!gMe#<mg;niJSWc&^}cJK@e&7sO1se?Lla-pS9$(eTC_SkA$NJgve(dh9VgFDk;B
zORL>Z=9B;j7ZcOd6B9%84Llg;62WOyR`&K*R&qyjI668Uj`Z|E0BdPrAU)mb3<U5G
zZ6-W^I05b?xdb~(Ztk_<{r9niQ>U<mEn9Hr%FoAHNvXu^1_MqPdi^AsQv!Wt=~AC>
z=~5vE2k|lQz4vDV3dQ)iLcy)1R&U>~RtxF%*YPf{2T4htok>Yuq?_=<#C@GZ=iYo5
z=;^^{Ll6SH>ZM@SDqJsaz8SmF;>CE>Y861E`I*cqfgzHR(9)8SfC~}N^;pQUV?snm
zo;VR1X|s8~Hd|WSz(87>ka+ppv`GlL-0PLgx$e0gIE@Ozq2ur@DhdbZ&T-vi=%uA{
zke>b^i2=#U2|%mmwg3D$XH8&?$YhO;GMNy&cVi*2uK^!^h{x}~6Cx|i@6XCoC;|b6
zLP%p{c-`j{LaA(PQ!05pa651syuNY*7#3BC#C5-QYdp~Fal5x-1%_T%hj+WXu_HO1
zSQ$M%AtdlINl7uAQ&Rp+pr!_kf>jutJ}tzOC3gFgB?`sn&6ohpRG^~+6YzMHN?tF6
z)8Gvs_ItfP3Y<KNA)Y#gbB@V$H^|M!&56r}Pl7E9+^wy>9OUJ3g@%v-FJ~DU6%`p7
z)Olt$T~Sd!UsRM3M~+}20|P?D#rb@3aYB0gZM=f}n$%RcJ2lluI1TPj268{JSpMqw
z(#Xj5ATJMVU8TZja7CF+c-LgQ0jykkmV}T1Z)>x&AAcP8jW9H!K(AMb#Kfwq#6%(9
zdJ7BLzaPqwJRVppB))>Rmzmkxnwc3qy>c2ne6jQN_2Kir{~kkZY{cD_MuP+Q&O34b
zF&gnn<>h$S?_Ul|OJ@sx)&y8_ad~-hu@GD!97Re>K|xB&qDB4vixvs-(MMR6-Hvxh
zNAcY06hf_bxzy_5Wv-p@`ik|vcQ5|p=ur%@xHuJLW+o7vbJnfHC+*q8Ezk(u?h8zy
znS_T20^#98!p*WwR#+&LEn8-_E?XwV`1nk}hj4frZEhAqrE)q|DqbZx4c>IDBv*pr
zVf@9&2+ll(g&73fVa*!eeB+b4x^SH6bo<E#Ch!w+xpwVxxnwe{RVFhS)~qoYjK;NV
zjmC(GojW5Ugn02q4rit{ghu0VXf(W9a~iw_)RN1<^Uvciy1H=48jUirdNmGZzaOvf
z-i@uad^x_JzV_NbhyE`K1e+l12*2+pCbqQTczEe0EEe7ifXya^R%^FwwOs3*2JdP)
zfyDr(NC{sqaf&P`z$3h9(pwx3*^-hEz{JE{q6#4acAPX4ovyT0rxRl5PAr`Itk|#t
zTfk<+RzREvufe=Az8$DkI9Pd}fo=ng##=!}#i!tlFXkRk$O$l>qXx;$c0=OV$;L(@
za&nrQa&mYx$7%2ytRYH*og^*}=lHZV906rzC&2V{sF7S?0>KU+o}4^<ST6Vb<#L{6
z&F1=gvzg!KI1TQ2{64jU+(URz$|LP!Vwi{TLeqpdZTyPE-Hg-VHTWUIuPOYWzmkhD
zecryz{YKs-{8r6r@EXi5FihsFM7AKG7LO7a;aQ8ncPvC%3;1#O9O3Vz3s=hj{_FG~
Xn+*9L`l4YP00000NkvXXu0mjf<{8y)

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbbn3p08.png b/extern/libpng/contrib/pngsuite/ftbbn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..0ede3574db0fd51fa9266fb1cb91df3888dc8dbf
GIT binary patch
literal 1499
zcmWlXdpOg39LGN{C5sa2Bt0E^MASS96&*cI%O#g#Op9f6Tda`V#zwgtX^qWXhM`=#
zI1#55hvk;s&XW|W)v?OmN^($fe!kE1{l1^if1mH`{bIW~+p3~=p#VVD-VW=Aq|W-?
zq=3BGn;D%*C{i&_7?4X9nM~yR0LYKIIJ%!+TU)zIAT%^Qs<O5&DJiMd(aF@*EGjC}
z)+QDf76K&a=jU@OIRb%z&*$gl<QN(fxLhtkA&0}s<YyWiS7v2pT?NR@%xnZ;v)L*t
zLyV}Xw6rvUx|EcZTL2P(goK1ESFQjQ$Hm0~bTgUEn3$NOM+tN~Jt`_HA|k@B+U`2C
zlDt2FFM&<izn_KA#IxBPDwP@#5J0*_()gs2s;?i4Mq{~H3WajK=s1>*waT#qxC!3?
zz5<a*^z`)f@bJLn@n$JzuCA_n0zDiKXK9I1Q+r&ubt`lMbimJ_KcNj26$Ky$G#$ON
zvH~p#n+wnkZ(hDsQ)4RMQ(jtH0^~CfK`1O;TwGKsRe=WpwV=jTgF7%kKM&Oal`uCq
zH#0K>0+^bb0-!+_LIFVlkOn3uCR$oXN=hfy)oYZM=LTO5_V)JX0F)aUb#`{Px3~8K
z45Cm8G#cZ?2?d2q03|3C!N$f8gK>%=kzAFOs;a7HXJsOhsJOUTC=>!T78DfJ0p#W7
zO#|fS<`x6+csvb_-PzgMH*VaxejVY*&B(||Pfw37i%v;TNli^nPEKZQ-I|z~7@ruA
z92Sce8ykD3^-OehbYx^?czAeNSXdrFNJvO<Sa57$U~q77GNMZv)*;t{;!pAQ^@RmE
zmUqnC+xy(PbMP4{h-A&MCJ+b!UyOOiwij$oOvo?{Zf<TaE-ugyx_P?Ww_k#1;OOZ1
z>(?(>_pT_EMw{BQ#m>$Sn!qg3OkVyw9#4k*05u5X^#Wxw8I%DBhvS=>0kTjoKsJnz
zkHa;PN~LfWvNvv&lMD4H5CQz1ooNFD1Ml8_0AO}^ckkGN(bYw&Ct|UTmX?<3ckj?>
zcNB^Yu-39J8}w6t>_9>;(#;tUCqEAdt`EKrw%G5dUucga(q-6VG498*{K%rij4wv2
zoEfW%jzHYO{1#TLQQ`9W=k@mzoI;b9QinWz_A0mp3<fU|ii7Uo6?z-~-FmyZIj*fd
ziZtLyt~2>_C3m`>c%tC$KR#Xus#^maPqG>$Ip&r<7PP}+lo3xrqrK0bX_;b9>)$CG
zYiDOPWRFqn6UcGDpA~Oj9{Dz;6-NwxejzAm$n<rQm6vD7CjXi@@e@{OG5xGtjixtw
z<}TuSbWIxWZPFtOcih}-Tl~MvQ-|(HR(Hk<+6?+FPLV7QO!B04L98aczu=_!`K%4b
zRUW;$6jgEB_F{vY@M%w9H@dWmQG5GUuEU97)3&w^mLgPzp8o7x%QPSVa$_8Q;9AEt
zy@@Xwt-sTLwS4z&k@UjU*Lyt`lf}6AUHvZ_BGVpBP#Z`c_(F4vxVv7~$uDx=tIc^Y
zc{SKq_jGxrqd7}5etz@a<P8B0%y7xJE~mfZAI@5gJb4YOVT{3DLuRIXDs;l>^KEA<
zw~yjS7UP676`?(gNA_%Ti&?JTRiQ)ukN>niNvk-4K4Y-(eYokz+n%p00U^e=@{X9+
z)rI4_;#GQ*EM)A{+^B9WciOLZ)vuJAK75`z`)0L0X_*pJxWq7M<jtvuqAm3Wv_u!3
zXzBchC(@B|nb)^(%CfJML!lNQ!X7v7D%Ih2#XTS{@P}D`n0Uk2F9u7tD0W{yRH|1!
zPU~IV*P*!+wb`iA=JI4j-ye&+(e{CTrY%Bu@<IKkm*4%Qc!l!cR3>yp(uq&jr<7|o
zLnIyhWR@l$6GSYpXJsSmv@J23K`FjDRPrN<`4!1UJg1FhP}`#*W-iAZNy`g6qae<l
k4AflusI^ml&j&%5BB<7^af|q)t%#yvf7%&aV@*!{AM<IOUjP6A

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbgn2c16.png b/extern/libpng/contrib/pngsuite/ftbgn2c16.png
new file mode 100644
index 0000000000000000000000000000000000000000..85cec395c01b305335172fe781aad11e485f45e1
GIT binary patch
literal 2041
zcmV<V2L||wP)<h;3K|Lk000e1NJLTq001BW001Bm0ssI2tcWq-00004XF*Lt00D-e
zG3b_G00006bW%=J|NsC0|Nox7OELfe00v@9M??Ss|Nj60ncj(G000M!Nkl<ZScTQt
z3rrhj902g|lt(c5h;B@c8Wto`5z*MhVpEu6z!sLFwWDPtp>{l69U>r1pj4E?y3$fw
z3LPC~5Eu?Ow>bx*PBc1kWIARHF=os}<8u$TxvBB}f1oy5P`W{kzl6)>j^6kGfA2f-
z`~RHyuLHPP3zER+<N!HM7NQh34+(rt_L4eMKuSs;26c6JfUR58z}T1z96L4zF1}nA
zasnsGD6x?uVlw4{>gr^$apTp%;SiD#R;vJ2Rd{S@z+-2p1bTZD!RV+NOifLIU&uTs
zaE81?yrhgg@q`IfRXqTjnr;GKFNW3KjX}4zVxZ4FgXd*s(ZFE9a5b7MKz26X)$9LG
z&+U!?)zyVy3pqr7Bq1d50~sfsq>_}A+FGpRrY7tX9#13)1Tctg+c1b-yYP7603Ht=
z!sEyY-tFzh#G0G016J#8z+$-u)Ys$P_ICWwmKHpkOd3!^xI`}9Pq-4f{bx<!Ah8hs
z@l!$C+mpa6uVBG1zl=o=4dMBY9azV0ZTAAVI~$CQ#DU4lOTcHJ;r~oe<Nts46&^qN
zWF|?t{_3lEZZ>0*+^SE_VlClnoi%|Y#7Z`h22w+;)<?kbFxKC;Z8rjkV+B~h9t)^C
zPklWGG&p!4n4F9S$B$nHzWD|do|wRK(%*jzsHxF`^Pf;kR+ERxJ~C?p-x3bGo?s$Y
ztCR4M<@R}c!EnnP$s;72WRWk)tO@X-u~-@!ESC8Aj*j^Fu(1CAu(0IhzP{vSyS=T=
zZugKD@*JtTAk{%QbnYZMBsgdl(UX4}#B3vxq&<5i=%w$zi+%OX8JstUhV*(j;Tfre
zw2>xK8=@ykF38Wv&SbTQ0gnee+4}W(MW;&#YW1^ZP6=>`(a|rw5FIVVzI~X$*|S2#
z#!gMe#<mg;niJSWc&^}cJK@e&7sO1se?Lla-pS9$(eTC_SkA$NJgve(dh9VgFDk;B
zORL>Z=9B;j7ZcOd6B9%84Llg;62WOyR`&K*R&qyjI668Uj`Z|E0BdPrAU)mb3<U5G
zZ6-W^I05b?xdb~(Ztk_<{r9niQ>U<mEn9Hr%FoAHNvXu^1_MqPdi^AsQv!Wt=~AC>
z=~5vE2k|lQz4vDV3dQ)iLcy)1R&U>~RtxF%*YPf{2T4htok>Yuq?_=<#C@GZ=iYo5
z=;^^{Ll6SH>ZM@SDqJsaz8SmF;>CE>Y861E`I*cqfgzHR(9)8SfC~}N^;pQUV?snm
zo;VR1X|s8~Hd|WSz(87>ka+ppv`GlL-0PLgx$e0gIE@Ozq2ur@DhdbZ&T-vi=%uA{
zke>b^i2=#U2|%mmwg3D$XH8&?$YhO;GMNy&cVi*2uK^!^h{x}~6Cx|i@6XCoC;|b6
zLP%p{c-`j{LaA(PQ!05pa651syuNY*7#3BC#C5-QYdp~Fal5x-1%_T%hj+WXu_HO1
zSQ$M%AtdlINl7uAQ&Rp+pr!_kf>jutJ}tzOC3gFgB?`sn&6ohpRG^~+6YzMHN?tF6
z)8Gvs_ItfP3Y<KNA)Y#gbB@V$H^|M!&56r}Pl7E9+^wy>9OUJ3g@%v-FJ~DU6%`p7
z)Olt$T~Sd!UsRM3M~+}20|P?D#rb@3aYB0gZM=f}n$%RcJ2lluI1TPj268{JSpMqw
z(#Xj5ATJMVU8TZja7CF+c-LgQ0jykkmV}T1Z)>x&AAcP8jW9H!K(AMb#Kfwq#6%(9
zdJ7BLzaPqwJRVppB))>Rmzmkxnwc3qy>c2ne6jQN_2Kir{~kkZY{cD_MuP+Q&O34b
zF&gnn<>h$S?_Ul|OJ@sx)&y8_ad~-hu@GD!97Re>K|xB&qDB4vixvs-(MMR6-Hvxh
zNAcY06hf_bxzy_5Wv-p@`ik|vcQ5|p=ur%@xHuJLW+o7vbJnfHC+*q8Ezk(u?h8zy
znS_T20^#98!p*WwR#+&LEn8-_E?XwV`1nk}hj4frZEhAqrE)q|DqbZx4c>IDBv*pr
zVf@9&2+ll(g&73fVa*!eeB+b4x^SH6bo<E#Ch!w+xpwVxxnwe{RVFhS)~qoYjK;NV
zjmC(GojW5Ugn02q4rit{ghu0VXf(W9a~iw_)RN1<^Uvciy1H=48jUirdNmGZzaOvf
z-i@uad^x_JzV_NbhyE`K1e+l12*2+pCbqQTczEe0EEe7ifXya^R%^FwwOs3*2JdP)
zfyDr(NC{sqaf&P`z$3h9(pwx3*^-hEz{JE{q6#4acAPX4ovyT0rxRl5PAr`Itk|#t
zTfk<+RzREvufe=Az8$DkI9Pd}fo=ng##=!}#i!tlFXkRk$O$l>qXx;$c0=OV$;L(@
za&nrQa&mYx$7%2ytRYH*og^*}=lHZV906rzC&2V{sF7S?0>KU+o}4^<ST6Vb<#L{6
z&F1=gvzg!KI1TQ2{64jU+(URz$|LP!Vwi{TLeqpdZTyPE-Hg-VHTWUIuPOYWzmkhD
zecryz{YKs-{8r6r@EXi5FihsFM7AKG7LO7a;aQ8ncPvC%3;1#O9O3Vz3s=hj{_FG~
Xn+*9L`l4YP00000NkvXXu0mjfDX!K0

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbgn3p08.png b/extern/libpng/contrib/pngsuite/ftbgn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..8cf2e6fb6aabf7c58efda0a953857b318607af30
GIT binary patch
literal 1499
zcmWlXdpOez7{_0ij?5*IPSn$xo>J622^AeZriDs|F)fz44lCrgvCaK9(i)p7!%%LO
z6LCs$SZ>MfJV}wPPOIFlR1QvYe%|MK-}ia{df)f+{c@b0>@`sOC;-qn<$!ZVI(j`f
zDj^kjGph?}%2e!GEGVRlO(*lc0TkamJGz}*TU$#c5*r&IR@vH?l$6w=(b>AXMMXv1
zx04DB3jtEEU%$?+<O+pCfk2R#muF-|<ned_g<LK-TaayHQkj#JlL(NVo!tb$;c(Q|
zhZ)h)85tP>^=WBow*aI7Nl8fw2?+qjY&IL9hsk8d#>O5wLZs8_(b3V7k&zD74p)(r
z6#W5wi5%j-eJnyYfy3casnmdg0P-cW&PSbeL&Go(2FJts`1l+vI)>xmtn;h^Zo*f9
zFF+!ZJUl$y-Q5WUf_a*`i;K%{;ch%0Z)Jtm(t1?CX%ln<bi$7xKcF3ym4zSy3>~ww
zvI4CLn;>X`*DqdZX)#srsxB=p0rJcP5Q$0`7Z=q_)!{xs9cb~i;5IBQEI>6tCCtyy
z&(6+*5T>W60ceneP(Tm>WPquush*y(ii(Z4cCD)F{LssxzP`RZfO2EwuCA_*j*dQn
zArvZ!Mq?a5uB3Dcpag{?+Sxf^v1cR6WET~cs;a8FIk{LYE-o$>i9`TRH*Vah2Ph~g
zm;uPo&o2hx^Z7bDJ92Y#uU)%#^(w-Tmz9;3nVA_=7L%5lmY$xTnwrYkv?)0`IX*ca
z2^NbL7Z-QB?Q~2`OjJ}<L_|b*cz6LoXlQ6ict~7eU`R+vDq@#1+?o6{KK?$wzP|7c
zjussC^71-={ycm_1R~oqY>7l7z-JS_iG7g0sVN0Uz}3~&+1VKez@Wfj%a%*<6dWBL
zfByUl>%J=rqtT`{H60urpc%{q%@q~D69^Qz2T+SJUKda<mqQtF@pyr`IUon+1LVTQ
z!~|RcnM?+Wko(Io3JPKVL=u3%lM`)laBzJ59RRbZr)TR{tbqX{Jqd?nw6?a+jE`e5
zZYUH5V6BzSuBoYE1Xx=jTNI*Pod{s_X(Vuc@I7OX`+oBI_A$hCS*LJVx1%|J6!9U(
zXJZZStaU|aApXGhR#uyF;qrxN4R@2yhNUc}54(HsQgRL$3Rxl+2j9CR@-q6Xt)``g
z-CiC|9`vKsoBpwqKhr=ue&f#H-k$rb+X9<xSdG#=3#(pB+93(bm@lN!-saA>PBUi=
zZ<oFA;AA!CzNa=MQP{tolc+6^ejV0hlfs?_1qTnCy(+Ty^yu8^U;8?K()t{BfOV_M
z>?YsBS+ans&A`7&dFaENu<+a*|IhOD!Fy5FU2($py#tmf$d>!3__F$7Rx`n0Xd`(x
zXNPrB#Hf{`Do)y8Y}67x>Fw{qlr}T!YF_4_IUZux-oC*~jH=jeIQPaX!`r{y1WzBl
z(m6wK7D&e$Zg(V>@2C;Wf~LRR?X8$9#=q?zc-|P5aetE9NbV#QTKGtM8suGqBBx#3
zxo@Q}hx+TEERS}!<VYtjsNG535YWhskZ$fi`)B-vIm^+<uRtT5F{D3iZnm=m9YJ4c
zKUcYBj4-;$7R^?K^)4RXxzROtxmv#hP5oE!q$5SIIEg;H_uKc8=KtRGepv|!HL+K8
z#I~(|J7yqRrKiY4-+!DRGl=8O_|>iYl~OZDE->d_uXdy?`@|M5G4?j`=QYAGR)#`a
zvNJkHwy@!`Y;;2I`Sq)+{L9pEnB}|hM@{;rXnr^QKIxlagyn~gH+uDas6<n_=kmeQ
z-PIGczQsMAy4z4{#!YsYry~1*U)+H?71(dqDsrP7Fl>JD-A_hPD*sh|5-pZZezZNI
zTBjQ-?c5``GX0PwW_dm>8`Y+1#_9&A`Q}k652Y3f(u)LcJ9%$iuabnh9D6vUApEqF
nBzr1Qcj<%PHtn77gx$)ZQM<+~5{$JW7KKwMop80bl;r;b+-;m}

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbrn2c08.png b/extern/libpng/contrib/pngsuite/ftbrn2c08.png
new file mode 100644
index 0000000000000000000000000000000000000000..5cca0d621047cacf1637cf7d77e997d51cc6b15a
GIT binary patch
literal 1633
zcmV-n2A=teP)<h;3K|Lk000e1NJLTq001BW001Be0ssI2{21+{00004XF*Lt00D-e
zG3b_G00006bW%=J0RI600RJ~w8+`x(00v@9M??Vs00000GbeoW000H_Nkl<ZNQups
z3ry2@5XZm&Qfx3q4QQ1H42F>)6_}Akuqmh*5X4X^rIbM;BH-v?$kU01p_ErCl=u4~
zL7fbz&H-~9!(}3aFu`RZW&unzb50QkgK2!RYsr=o3t~2tT^d3tzx&+X@9uj)%)Vj6
z{|IpB&Yj-g-pR?y{}^!Z-o3WAwzRagh=_<-fB!T`$I~7jJzDL9k&%A|7#|<+>gvkP
z&5eqRQiO&cb#=`%Gt&SnAO*+-su`xq!J$j392p#Z_UzeG0aH^`SFc_zD=UkSkAGjG
zNZGY3d;R({hG_tbfDeIqE;r1<L9$|n7?A6E#mkl*jf`w;Y#bOEc>MUWVZftDkNW!h
zs;jG$lamt?5{`w2W;;5Ta5(kAS>OWD3k(34fhLB@x3Eyz+ozkGX8`3uA)t^*Vq;_J
zARVu%si6?50P_I-{r&0b>GXAy-pZYvJ_kMn+JSRiZt1pd#bWVg8=D~(>oza}`~v)>
zM}7e)8HRFA`iDhFM^mix0K>z>DwQfHCnqyAGc`3;6%f#2ZhqFvO5^8uBq=H7FUwFU
zT6XLhvbG*uwdz+cchJo2l$~8_P|)B15EmC05)$I?@88+kIS+9E{(W+tk&&UwQ56&v
z(A`o(AH0rH_Tk~-0RaJGvDnww_wL=h^8j=?>6z)a6}IeCY}aO2b*Z|fq@=L0@WhD|
zsSDdty^(jSiA*M&bM5WzEtks;bWvVj9&?GoHDC(zc6o7eG4)bKMMY_8X?Aw@u?6h#
z;lshf`|a#hY<3Bkd&JHz$kWs3`0?Wg0OXPTF&CY{G^|Igi;9ZKH36!ss;DvOr&_J1
zx~1t&sZ>(M4;(lkk?c1!`x@w{b_L!AqU`OZt*xyF0OXE$lBa8(+d4*aQ!-UaQ=##!
z_w+pDSx{e4UteEaTT3@Y0IErFaIj1kyl&n1z;8e!i?yF&L_nC8m3(Mu$N-?Zxp_n7
z2DAX*=>Wn$A?4)L>VvOzv*1+iR99Em(9l2wMRh0dROro{PXe>RH6x>UEG*vQa@TOV
zQlU`t^yyOrfcExwL7@Om)cL>za2|4U%W^%=c<5%V3NB?X6h0+EjKsu5@-7xf85_?~
z_(n!?E-s$Cckkx$Tm=FtNq~V#ChO_xan5qaMSv9N2jF-3*7yqRh3Ek)Au1KoO;8fV
zprIvzKyXeU{%KoVxrc`zkCz5CFib&h?McIcn>TN|Dcy8{RDkAq5^L3Kg|$LmUsXU<
zBBJ4(W03sGWO5UeaSET!R&3c4%;9JOl9gkorlAz5VF1mVSE84$J}Q`0nqU|>1Di@4
ze5+F&_hR?T%1UBTp~Aw#cJ55qhku#R59RT^^+74<V`&*UJw0t0K$0tdPps3nGB~6-
z;2WSDObMg=MT<Q}d*)h}7<9t|K{N0Nkmckgv9NfX#R>-!fSSE~<7VgEJh?uUa0qm;
z8Ez47t52=QkANEJ0t(=x^_iQy^73*TT0XxG7zGZwyYCSQ1YB+maEUU=$|_zAke{D#
zTyIS3>>TO5U9}y3y6WrNG#}mt-ZU1(ApHmo3|zUggX&{s6zS#V<>Yh_y5_4hF$wDK
z?p_S=<jE851+BBnIqYCqcy#!(^ULswehH`{(MV{vi9tFjl}eW{|A;(tIN{FDA#8RH
zaFNg7+t&8w>`P`~WeyGw#>B+X26iZPz^D41kPE3=O0g4z6qf*N)=*PsGE4-+(Dp2{
zw2Zxeeeh*hh5=+_V`EuaSwV3@IIpj54kWn}jYdNZ8e`JrO`E(~ENUAnPWZ-+iMMY3
zY|zhwfLVQ0wY0S8#Df-Q7G&8n5<6nh7)vA)kx0bn+nAbqczMM?d^oX?lf?jYc4O#<
zON|S4tujMN`;Hh?Jz7|PetuiGZY4pbYg^pItKUTv6B8tGw0Wp##Go<Ww{IWq7W(7!
z=g(hxd`U067cX91xpIY;HZf?7DT9uVj-?!2Dqzk=M@O|<Ep-<?L6&~%^&Y=7Gc)u;
feXS#J{B`{&ejxm6UY$v!00000NkvXXu0mjf$4>?l

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbwn0g16.png b/extern/libpng/contrib/pngsuite/ftbwn0g16.png
new file mode 100644
index 0000000000000000000000000000000000000000..99bdeed2b3b8564302d449e6578c4aca0f6261f5
GIT binary patch
literal 1313
zcmV++1>X9JP)<h;3K|Lk000e1NJLTq001BW001Bm0000027&o&00004XF*Lt00D-e
zG3b_G00002bW%=J|NqFf-^Ty|00Lr5M@0Ys6ss}K000EMNkl<ZNQq<kPa$BSsR554
zpFH{TBUuK#c(HYBU0rHw)J`}3gdYn99|;g`z`J+*_jh)trzcME*<~i86`=l7d8_&y
zy;lLA6TPo&|MLfr0iQk{IWl!>QBlsk;7PU%bhGrgYd5Q9YAv@pu5?I(QEIFDO9PIa
zv;_;!pa1a#&4BOUPo0`ItE{ZJIBk{3V?$2;ETe5E7i<FTWX)R)1FdJfRv1^SZPR7e
zdKuN8msea|RyKR~kt6Tk!3{WbroO(ctP}|R#Ldmkn9b(e#Dv<U$OWi5&Ue1(zTGv@
zG0RTQ{DPWU&b(46$jX{E3vR%jJFTr99W5=@)yW(#p6>FAugap!!JvpW;c(dAAQ8V<
zZ&BY>NjD*)1qCrNK|y=>!VP%!s->l|vE8$;ud}nhz7j7eD@#re2?+@B@p<+PZorQp
zO@$fmNmnXtCft}jxxc@;xf%mh0YPPDR#td8NVBJBWF$%~baiE3DVf#RJVAESq^VP<
zPoFZSy}bqv6c$Ev8{HHsktow$<F==%3B`a(lQP%k`}S|_&z(4N%9QETXU?2Gd*;mU
z?)v&VAgHY^FHcGexukksyjb7_j}Z5Ded#r8Pz;zdCH-R-L#ufI#tHG0Cr>V{lB`di
z{%hX6Idl5@>guwxqN2jr>pYX5E|kJ^f&DqRx(f5PYbXXRS(0v=B3pVK=!U{clUf+^
zwk5aa8O@zLfBu36RaH?@k&$+SvH@a;con5$c|}DEZ2$iLjbgyIZE5`R>8TI9Qu-<<
z%&Jo_i;I%V`!i?Gym|BImy|?C27OhSEj^vT%kqkchm?%||Dqzaq<s8%N?nFcFlY7Z
zeyOTUr5&Y)k<A5_vuDqpJ8xcIUSy<|jBJ3gsJ6Vz5+yDncR{nc`e+8+xRD%@VdIgX
z6W#kJI=v*SWLCtR{7189fs9B`51*tQ1GN9P`FgQqLYjPzV)n<6qZ#n(RpRl~hkn7a
z_Kkf>5gD9C*CIj-6lTnrHEYhC#6(Y5*#J=&#dFf1`ILEld3=?QfBAxDz@I+}XOr8)
z_eUHoTv5Ut_PcOJ$k~z>P;}0k6%}PEBIC}VVH_mAk5_}&Lhw>xFqZ6`_b6dX!jw?c
z%!-;Dfwv2)g69`EgOb#=Y2o48uO(Z#zd9_?))qGsnatzc{v3+|Jw5UA=}QBbWjreT
z8u2D?TToHq>&cU+PVMgx3sZ_0b>T~KcQ<txnlHp7BzN>E76X3$TAY#mJXtlpDYGZ7
zBIi@!?b7Or6DLpZ><kT+F&5$xoMmxVG+rc9{`<DH|NpTV00I{-<mRTPrajKMoUIqI
zu2iYNf8xZ(#?Vkjb$(r*1_1$q)vBH6IsgC1X~6&gZ{D=ErB$W#Wo8D57c2Dk_V-s+
zg@oug@`-TQb0->}crfArf4l~O;$zjSbkp>uelLq>cX#*pmXrhs+uBMi3p@E(ywgBe
zjiXq<a=559;$Z!aj*jl`+}xlbe}8lH^73E5u&KpSFT8)hU_o<pTU$p*dU{}BK)`|p
zfB#}viL++<_wT@g*4DPR#KfSW?b~swB2cy6yEkD%YU-IY_|y=nT)%#O{20Fqifd;8
X;LMiQGdCU+00000NkvXXu0mjf3u}w^

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbwn3p08.png b/extern/libpng/contrib/pngsuite/ftbwn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..eacab7a144cb54be28f7a5952a2fc63fd883766e
GIT binary patch
literal 1496
zcmWlXeK^w#6vvOZ$|54&sN1DSM9q^>(d99%ke6YZ7R$UYR><4NHs#$&Yi#Ca7>ZQf
zh+9gR<t=%;Pf{e)ZIyS6%Ec}2uk$?Toag*?&iQ=5Y&TbXRg?}208||vupUU){h6B-
zkcz#L*@-ko3dRKka%m#d$vj^G`EfVr(<j!~*RK!=jg1d)+1Ztrme%R&W@%{^7Z>l`
zNh~TV0!S$+DBx6a1Ofq{&(F=xH8LV_xm<uE4u_M)&oVKo%FfQd0+5xJ)daw1vsF}v
z=rJ+r>FEIVsi~<q0VDv4iHVmlUj`^)u~-1z3<e`EF7C(?0*ywCiHV7digKuSxQ3i0
z9|+)2U=#N3W8$;$Y&M5Np#%j5kuH)nKWe5K7=)wIST5Gj&+l0AF)SNvoofwn1HJ$(
z0Fg-a^78WZ^u*)w=BeiH?(X^meH;#FWra~!e^jrg23-Ih@csLDXahw>0f+%jL$9u`
zLJPv?JUoFnFJG#wGn8wTmzS3TdFBBKg=I@iODbh5a37!!)Vb<#2No9>p&FnH=I7^U
zXJ<hG)6>%cRLDjsAP4}`!PL}LTibZ!Mq3SyT4m+=!B>O5y}h{r6~@M$ot^FN?Y#hl
zC{!YqO1H65P`C(Cib4@io^-%qT%t%M_l+BG-MTe5CliT8B_$<7p%9>{u&}TmAU{8U
z1|TmluLOX{<7sN{%E`&Oe*OBjYY0DXW@ctaMn-ITY-&boT3T94N(x;~Eh#A}At?a~
zCX*Q-AAhR#RBUW)baZrNWMo7{L_R=RSXgL8Xnb&RXlQ5(VwZBPQ=XGwpr60LKYWFw
z`A2<xe9oRd3!e~yNOp8P0)YVV*@S0ef8O5Ilnle*;o;%t<_7(sm#?>N+eLT=&d$z1
ze*A!+zAFx=Qm40Uad2>eW-t#nmzV#B$CKe6KrO=fr+_k<49bCn!|~0{0XZlSAO|KU
zCg3VarBb*8IU6>}$%O|Jhya1EuGE2nfw8f70F3VL?(N$#dU}ZTL@bux($X?BHikx@
zMxn?6>n$vn+TI5>$O^e=4_7?cei{z`Irux-V<AK7R|mv#nT}Y@>7&^JWYHn|XJb{)
ztaW8aFz!G>3$xX@Xyx4VhMGi|@Z{yRAy3~u3T{Dzq05Alkb8H9K1P4F-hT3g)m9Nh
z8VDfQoBpwyH`740DZKl)ulN4y*5D>vW}_t6!m7uTdPs~i<_W0O@toO~X~vAfo$~kX
z?99fT_mqZ2GV8Z9;>{}~Uxu_<#PH|mLqdkkUKd+?dv$CItbLO(X?+IM&%D`Wc7tc(
zCSF9>rsLiwKlI~HSa@$u_-AGM;JxVT&UitaVZY^ZlI8v>p0qxM*^Cbq*ovReoy54y
zqc@kKDo@y7XjB(I?dj`Amo?MtZokTNvI#Y7Yg4ikp(^za=H6PR`vz8+;AjI^J7#Fj
ze936To%SmgyKal5=cgBHdMc+%aN}M5FB+rM?@v-1Ngeni3qNspgRGNZ?7C+sXI%1X
zu&@5<%1FnPY{|sA&399jf*Ki-lC51Xe<nPbvmAN+8dM|bgE~XzX1gnOBWa6mXR5Z1
z;zyQP!r993o~6UPH+jUZRO?jgQvT&XZBN!NNu<phe*HGw{NLN2h1H-i6MK1QOzYa$
zV|wB>TCyzc{m1!Hy?E|SK;2qE86{)*9AoayT6^+}UtG~L-LQ!_uNscFG7wOc+;n55
zi%O5BBNH<3FJF{p3sXbkmhU1SHR+V;^14{}iC_7{%m7S+(d!q3rCSucFC8q?ub!ax
zF755m+JV|^+;sBNR8-&ZOS{mH!F^^e!qemf2F)+O1xWD<6~CxV>WZY3AMK7S*J*`G
zI`+z}Og|)wnBLFIM>MEg;<Q3i{c|bghZ2j+k_&iF8_BS)M?uV3i94L0A8|@SoHZ4!
iwfsSQhsN%Af-Xf+tzG99^G90|i-O|`S8S~vIq82KKA5Bc

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftbyn3p08.png b/extern/libpng/contrib/pngsuite/ftbyn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..656db0989ad8403c040f91caa6d1a79d11713715
GIT binary patch
literal 1499
zcmWlXdpOez7{_0iP8lN7N%eH-5mECbRCIVu6LJ}*)zWIN!wR`=Y?C{)w8m!2%up^}
zoQPA3!*WZM^CU&GI<0cIayvMc^YcE>`+lGIzxVxozicm0XHC>L6aZ+tx?p_}HCXEn
zD#*m%$mv8xm4flWfKsN!VyxgCfbvH#cVDN~)zxGIp`qbnm7`-xNlC4N0Y^`-xVU)x
zc4ARc5kUI2YuC7yT%k}X5D4<~^G!_&JRT3Ah|A@21RQho%G})CWB?9_(+I$3vo$mZ
z=y7pbSy=#e85tQj0b~FvDJhpOT>=oZSS)~U27{51kZ|Y_fkvan#l^+M#JE(uTtQA!
z4gv@uunBwiF!3Bbo6V(AD8a$Oqzfe7&$^k$#*t_=mWTEC_dim61k1+S<=X+=fH{C~
zKqL}Ro;-Qt#0fkeZ<S%??d@$OG{WI<wze2;?MHQ5TF?d10pGuWhc-}E6@nDdH1x{K
z3bY_>LZKPnzIvst%}~3mwzRYa$TJT>Br088T+}GlfcpTopv}{U+b}yj3)KLXFf%hV
zH8ll7n3$LVph7M}0YLze1r`<-`ub+;*E{Iw)TpV=^uO-!?d{D6C^s|f?CflBZ|?=@
zN1;-vRJy&ripm9m5)_JX?3fD%;}Jt5d9PnzRaG@Tt&m70VzF2x5&<+`zka<Aps=uT
z5}=@<Kn%d=^L2H1<mKgEy?XV^6@(uzCnqO6J3GECJ|jCLGcz+iJ)N$lm71EGl$wMT
zlgUg>Og!FtJU%`?Ha0doIyx#Ust_O|A|gC0JTW9BJUl!diAx#Qt-#Gc$Uh(;0OsLv
z;o&o9&YV7d8onR~ksRrc1Ofrzt2y7?In>$0f((P;<KyGy<pnRmu+VVx<_qu?+}+)O
z{P+QDxhsyOQYSWUba8QkCa?;zQdVBT<H>Ljpax;QW}rf$fHL6XZ~`kUKn^MZ$b-?*
zQMe3pxg3%q@0VYclp=!&M1UYqPikLZ-^j=Z07iFr_m(XfLqo)RA{I+;X=#}p89}3c
zQ7AINY72|Cx(f1<1BfS}6zk)O2Zt|%A!|#3n=^L7>E-reBy>5hSd8!C+(5GA0R5|(
zCU?rNq9X*i?^+A9)vRdw?6dm2DISq&OPK>F&h1k13hobIB8bE8-4UHJ{j2p>b2F>0
zJdV^CNUpQ^W2IoSo@jsl&fn+!_ExusG&(RFWck*%JvP(>Qj{5ANTt5dn`)V0Od8)V
z``FITX~_FXsZSxZemf;qUmltp&}R`NpM{2n4OqS@w(~pLu_37DZPJ+CDa;Gz%|^=`
zd}}Z1EV?EO_b%<BKX269Z&T7g%M<(W#a4GF3foLx*c>I<>>cOJ>%y2#_#mN!^x5<=
zjJGmcy%bg9<b1wCTlA#oc{jSWiC%l_b%C3GxMf@0I$H^<!pL~~oo&{+pmK8@t?zQj
zB&|sx8?L|Io?O1;mP8&p@$GI;#kd&vzU#%yhS;q8W0VF`2foPKU)o)-=oA!t?%K|M
zFMHkpyza^JP)BpFZ1k-9o%D6V4UA~nrY?^^lO9al3_X4Wno;!rZ39-8J1Y#LX|rvo
zDmM?~hZb3)sfx&+#e+LH_#`Y>Z>un%{403Uo~AEOp-q|0FAO&Q_payLN^pd^v$8v;
z_2>K%L+MXinj+%k=b2%{MBZdz?a#ncO7`Gc#`N2t?P<&Y2}MhElSclGW+d9ySV&Fv
zGKiPYu6ryW8ddns&8aEAjSocHe299~xUJNH-^IF5oEHo-12IXaZ(jD7Y*g*OxWCk>
zdX(C`xVuAdD@xt0@z}-jnCHJQ?m)YSJhyBS`I7e;H@#X2l;c&(f7KW>kjTeAJ04Z5
z)r*jI>{i%Xd`gip{hpQ$=}<Q&=!Inj<WtBGW!9Hu=keS&l1Xikij=XOa4@Sd>bQ!O
lGajP1^htlK&dv|QE>+O1S>+WAhFg({f~%7!w#Jd1`acy)otOXs

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftp0n0g08.png b/extern/libpng/contrib/pngsuite/ftp0n0g08.png
new file mode 100644
index 0000000000000000000000000000000000000000..333465fcdc9f10f7f25b2d999b558f5421983ecc
GIT binary patch
literal 719
zcmV;=0x<oFP)<h;3K|Lk000e1NJLTq001BW001Be00000RuLsA00004XF*Lt00D-e
zG3b_G0007pNkl<ZIE`bdCjb~oRPgxZM?4B%Y^_U;a!XwJ5UYZB`#aMUea*BqR5bJh
zCSLi2s^HU+sYN-#c6tUn>e{x-64Dw5ISbDJfGPNXYF1fsnx~<Gv8j!ng`thBvAV8y
zR9<n}>?7~M3eMD*m6rOMo0;2$rUW>-c(^**S*Ycd0zuX+u!1|S9WB+#F78QX<>lo?
ziQz$h-hRnIW<gBQUa*2!EsgDco%NNdpe#8gz~>oQ!H=elq>2fX`<ts_psK1eD?Gr*
zGZN~HuFR6Y{z+4(Pie1#g2HHH5eZ$lCa8i*nfd+w6Q@j{IeTVzeO+B`c~Xd~xF8RY
z{u-!)De0Ll{SzinuBx9tZ%$ubR#dpIv=A=`x5_oBf+guGrTzVrn)8zL=FVSG6%}bG
zE5<9uD`NK>s$g4Md}>$Ugu1e*ygBpcmqZ3DNb_5HNEsBtg8Fz$MsRgsRcUEt!R)#7
z@*=Hdg|%Ijgaqfp6x>M8@W|<nE-8t~pEY}KdbqN*fVsF3pV)Djf>(*DezA>78ATBV
zGiJ?6^pq7<lHudwQT_r`@FyWTJfg5TyfCC>`pj8TmNNXtGQ7M(fr#kNOGpUKtO+a#
zE}lAlTDXoRkAt?j2v0jgK~H>oU`AO)UQprWsr_L}qI~YALPA1E5ej}SPEJnGOv?!@
zojAEOR7Ob9QdC4?8%mP9keiy8ksVOlKd~`Xk)KCEK=mA2ntaoimYx|<+}mFjqR+?8
zZTJ8q(f(PLp6*}V-CGiDD=qBv7F)8vQWR0&(VZLQZ(jZjd%k$Tpt-FhJuqOwUu^jT
z1pXapZA%Q=jx2<p_3lkbJyVZQLH*aq_4pNF008$!%u(56)m;Dp002ovPDHLkV1f>U
BP!RwC

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftp0n2c08.png b/extern/libpng/contrib/pngsuite/ftp0n2c08.png
new file mode 100644
index 0000000000000000000000000000000000000000..fc6e42cb420fd08ecd78340256157fa5f8a22934
GIT binary patch
literal 1594
zcmV-A2F3Y_P)<h;3K|Lk000e1NJLTq001BW001Be0ssI2{21+{00004XF*Lt00D-e
zG3b_G000H?Nkl<ZNQups3rv$&6vzJ`6dKHj8c>u542F>)wJ;-zU<0Ta5X4X^rIbM;
zBH-v?$kU01p_ErCl=u4~L7fbz&H-~9!(}3aFu`RZW&unzb50QkgK2zirzKlPEQpyV
zJ88Z&UwhB*+;h+QpNot)Z1^7mZr{G$*Vi{SHT9YSckkY9Z*NaePmhd@j0*@zcXT}E
z>DjB%+#enNPk@PuiSF+1yu7^V=xBLZ*b!IPd^0mOpafEZETD#AngxPxg<^DQ=;_m^
zO9f0%PhYumrM$d6AtB*?xjc2}&YX4Y${D5+C<Z<R5?D4|AP_HKE&^maUWu{sk*KJq
zrl!Hc!AFlC=?6S~_^`jfzow=pB_$;>G4W_vSdOD(DVN&-oB_@QeZU}a320`R0!vG!
zgF}Y7c_vT+6ajLvI4&-Z7Si(C+FA;c5-<-iFfc$*`Z-x=6;4i{1D^pMz*&|p+q$(x
zB)Vj4J8WQZ3z!6c0e;dUzW@{rLwimBm&L@yP^|L+BO@b9r7|}+H!CYEEiFwM7}#lU
ze#Y8b?eBj$IXU%j%aqGow{IV|u^C^v@>iA}GBZ1AZ=V(%{Ldfa<Ksg^LjwW=y1KgN
z0q)(qN3Jt7GnKi@!oos2TYCAys~GJ*A|fI%Fi<2C`T6<XxpQY8Kzle@8FrO+oRb{a
z7FSi7s<gDUsHo`p@#AR=+Yz0Scgl%WDxGuf<KrWf$@ElFettf4k-=498nO;qNl6LS
zQe|ajSy@?5PR`K<?9ib@AtC$h?Ufu(Da#(Vw-5I6@;!F!m>vLmWItxn1<b%^)TX$&
zm|PQ}y1JSQgPtmtivE_aGlfDy8Q;HuzgWD_%<OAmfXWqk7l?LnkhHb6=>d>CixU>w
z(z&H&q%@~cmeiGMuLdu#(_V!Qg$)f2b#--gLIj|kgoK1hr6FtAeh>TxG#MD|V;DCe
z+}c_;JUpxi(9+VfzG^*Mf$y{cVZV^}<lE+pue813RO3`%U*Fi+NDW1KC-0Q#O`A>t
ze*#wx4d1b}e2ZmQv#dlY6hC?LL=T{&qk~_>M>ADEa39<U+`RHU&(ogT9;=2+xeJ9)
zn;=F~QWAL=iK2~+W+{9_!*~}LuU)%#Sy;I8`4W-<J)KO}+uQ4$?TiZmDb5eT@9?Yj
z6E+CZ3sk|a%#BWhHbD$(S_1I-XLaG9va^$Udiq;fqyvo%Q&?AbLO<ZfjT`O?cP$_d
zpgx|$8r2$Molsj>m2fL{qvo7rko-xdG82;t3ZKJ~Z{8fj<!S(um7}JnVHBu-0QH)8
zlD9TLN|;ocU<5b~+bUapt5qD25|65?Dq>Kg!o$ON?8wlCe~HHnv#{{d1tq7Cl~vHp
z%#3~jNv`NUkyhKvAxIVA8=wbFDWm<O!S3SSb0td*I$=J)1^5HVc5)J1TE1;y5CJ3t
zwR`r&XUw;Ga(yuIAZTF=+#}srom_<<0Ts{<6v9{IJJ)v=6&2L9JYG961|0P8*v;qj
zSvD59NIS^RE?EpvP*7mhU_|Qd9Ob-Cxefi=>}$)k06v92)E2}b{Rj#QTCt*&@?&Ti
z<?Ze5<a7Yq;;T0?3GV6XSq$*_@ng+-jkD4@{6Kg_OoZ_{V|=0;0xF2rV(M*TkPb>D
zl4Z+2B9B~dgtK!fhf@n&;PLjfw||-Og6SEVLqkKcv9UCP1w{gUs+$RUkf<aSJ26Oc
z39x!K6=fE~L^2Fb&tfa9xNFyjUUa1&KsG);o}HZ?93PBxy4>bMoF`VR)x@ASCQaVB
z(Z|4m%7&5?v0+2f&6_{#^|K%#LswL-t*u(|pn;hUX^xb{ju_O&VzJoG&5g&iH8u70
z_D*>4U~(ZRivi~B`tWs^S{JHXMW%x09Wf|-G_d^r{kLq{LV`-iwz!9v--{+ECrRLF
z@=(%<L2bNu?_QcM^zzxWXD?m8q?_II=g%)+zDz@#7}UnJgU-&*r7T=3V9v(I#xxoY
sRoC1V<n;r{W@l&VhWbiN-uUhMFIDPP%w_<`9{>OV07*qoM6N<$f`h#14gdfE

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftp0n3p08.png b/extern/libpng/contrib/pngsuite/ftp0n3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..69a69e5872234d96cab4cbb017a0933fbfedba81
GIT binary patch
literal 1476
zcmWlXc~H^`6vv-Om}J3dn5OOMOgg5aIm=3#R<M+qH<wwuc|s$3EM6p8%6K6u9;kSr
zW`|a0q1&OE)~;HVyY8fRxoAa*<$-H!x*ps9dNc36f8YCjKcb)j@6G7#XaLykL#5D=
zZS$=+8X%K$sc-;Uh8&VV3H0(BU8gEf0O(Hy`7sV{-5Q_8V%@%duZ2u*XlPK_*objB
zxm<2#6<S+c3y@P?T`g&rR8>_~R8*9gm+#ueDlIJqsFg@0;tH{|b8}HqQ5Jw$Ebasl
zi9{wQqx{s={QP`?_T1du%K+m5+1c6W&Yc6O&&<pOPznTs)2B}piLCVW^wiYU<m6=P
zRcbMEl70+86idW%a5zI3(?uc)hr@}DjSY_vH`AEq+1n@L@sv_ZWMt$%`96w>;#KYi
za0xyG{0*U@p&=n5OeT{~rxS7s!NI{ht9Awk26}jqu-LA43<e$p^uyZP8vF)^hE?zg
z@ag!Kl@;hk*qnq1@MdHLixn8(FkW6>2IQH$P*->1%a<=E7fhf7KmpiNEL?|$g$1|@
z&<t~Pb2BqDPz9epeFES@5kdh$0FV!^uCA7rjz&fYO-<X3jpv463=a+tmIGXLbQ~BM
z=<Dkn1Q<r6v$<UU{{039@c<2IH0$tTDv9Ku93CEQWYp5qGCQklY;3Hrudl1C1L&-&
zsc8q0$z;<2m6etC08**c%*?v1tgNJ@q_`O2S6WzDSWr-q)|8f8keip6my?sj$6$m)
z;aTBXq|Tf<laY~e<l&LDw6v6z6dsS4l$0a`NJvPCONz^2v*Y68au8jbD87}xkui}`
zQBm*@?3L{e3ky4T>=;ZU0fm$KWEP7BFz+mN_CD$D>KXyBfJUPQ1qHz$U@Noz`t>V3
z0Y5*#_4Rf5=AAr|%l))v3zbTRZXmD;`udA>dIa18XhRr(3s9%iK@&&<11kswKn|(|
zC<Col3+F+tRznt)p-_5yi7~8DfS7;)?$FSXO7#{%pj0Z&%}KVlNc5o;3ct6vcUq;w
z;~8jl1i;tc%uGrY>Kfuzi4TRu*jp4GWDgcp#{666_U|?<$;@lL6fyrT=v@~MF43;U
zZ$6b_)kkb?TQRlFx@L1DFHuvCdiGRV@qSb5o3SyX=dqWIo~SD}lgtU8-0hinIc|l^
zwZpyIy{+Kp3qku~jyuQS{wOJTffqk}ylg!rGf@@8WYp~qR<LMm=iRWaIs+%Z?EyiL
z$3>TEe@i_6M#f}U2WR@4MfM<b4D-Oq=}GlXLVBLG9p!kmr+;x?B)}4PFLbk=es%FY
zu>)1<JbF~eTkdn`w79VC<h(GqB1wATjH$!XPL+ehk;YhC#-m@R3T~JS>HJRjPCMx~
z7uM(-p3*y>&A)fhi1A3;cS(L+J1;&pqWL&it>CX0-+eBqO{=g-lKzNGvG(`sNqtRF
zeg3%mDzvL|F3Eho_0DyETn8H%dc!?dA!#0>Q=Vr9#{-Ga&|1#6CAW+Q0sfY$`N-&;
z^0c=#@%4)8jy6X3lL6u3JAW=?c#tm>K2a$#(Q?|Uz}T^+pWADD@MB|q8>&Xr948aj
zsY1|Z7&ad@u4wr4W%TE{WS7U&Rh^yI#(OsCtq$vQ3|A*M_uLm%-A~M)I@BiVUy<b2
z+cpViZ*y18Fq8S3`1fl02U-`g`*s1z`K957gEIq~O=*uih9>S#YR$&g!`CNx58tIE
z|3D@=NLJY$Q%;J12ZU?1w#&^2c5EzDN05DZLoa2szJ*SEwwg0|Mem<$Yn1cWcz^cq
z-}lxrB6iz%k1R&3=>`|KS%};k)l(YskH!jI!g#-(&O>3hx)5(GX8X3fe_&q16?&Zr
z)72bEymR&OySDOI3mZ0C3tSEiO=8X3u^BG}uBukDWrMyZ$LQ%Y4sr7@il=hRi%!IK
N0G~qvls0mN@PBi2fm#3n

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ftp1n3p08.png b/extern/libpng/contrib/pngsuite/ftp1n3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..a6c9f35a86271c056e955f637a8769381eb03827
GIT binary patch
literal 1483
zcmWlXdpOez7{_0ijw~Xj6ZLfH5mEEBP|@KrEtkTuS}m>SI;>1?8{6D(v$V!$$}kk^
z;zXQM92O%H=ShmnbXw(ZQ8_r3^Xq+{_x=9)zVGMz<@$KL>7tBL0HEvPj`Ks*<Y%we
zKql^LZYLs|RIC>k)Uu?Q@xn6z>Z3lMM-Q#6tfUZ$jg9xOySS8<mDQP;@C*%0N=i0w
zCKVSK17uvje3@U(7mLLrk*J`cz|xW^5C{N@`FuW4#Iv@p&dbY70pRg?O#oajS4U@%
z85ftGoefZ*nVESFKmm}Nnwp%P3{cA9Z~(elELK87!oGb(27?h77Z(!~<6h%_5jjac
z7$A_yCGOb4Ch!PcE}u%JhJ=KW&ym-ESf6EXPDi700$e~qz=4tjI4;hyz!Bgod<K{U
z5{Y#D`0-=Mju8k1+e}+uUtcq^86J;!aKP&8Kd9H!gDwC$eEaqd+CfuO3^G77(96rq
z(2B4LgBE!8{JFk9OZ&F=;^HD8&)frvq<mpvL8n{??gG?-zCa&t!u<R^)Bse&?Ck9H
z^fZWJa&i)Y26+et1OY%cU@#aXBP%T}X9I&;ZSC2C7X!V$y#)Z3R#u&zogEz=y#NC!
zR4R?ebaK+rI0sOMLJ?hE-LY7&7&6&cOY8de>oYSdsZ?58S}Ku90Gh5`xl#{MR8%wt
zP*_-43Lq2;*RS7_pPzr}(xr<R5q^T)+}xa;ocN0P%$&@utgMWT45pr5T3T9CS`t!h
zHajsf@o?MW`1ttP*x2ak=%}cuB7n%q$cU(j#L&=)h=>d%E)}>Vg+~H{0|EmB;S209
z+JEZQsgoy9!bij)vJ2CNNF)M$vKCsqg}Grc6c_?OKR+KIALs+qBGU~U&cS2w^z{7x
z{X6{3T?w5=n_Ror-Q69U!8X)ZUHvP8K!G~|wFu*%2C7slr~p15FS4}-<e)-;d>9)W
zgA1TkDj@~(fB8jCjUG%S0R(${)B5}SM@HTPu)4duH*Un5nj+Sda5!dbYwOg=2pWA9
zg`xngv~oCl+wa{*R;b1Lc@x0-<4`CPvRn@w_UQh+Ac}Mk^OKb>f7-E19*W;}xs}~!
zRlIciNyF__FM9f7*5I)-+cbPa1|k-TrQvsONlsb*)pnz$h0|UcNA3@z)MNfwE}Uv0
zIbFH+_Zk14HEp3y&g@1-ft^E-J#CK+WhE5TXruYlt&^-N^P3g#I=H!w`R}L=sT9s{
zCuD1uhCdG)aY*zhVd3F}HZMyY{g2C62iLwz8h1Q_?PFhSvbid>^O4P?YqRlh((eZd
z#_aspCH=EBx%*CRO=qIG-J;L_AlZKBgiu)@&Tb|Ii=AapW?Zqp>gYA)sH#J5XB+h;
zk9wYVqsyC_bvIrV9&w7WX>VWUAVpP~na{j&$UYNXX^m&}Uyx5RnnjA&4L3VdD!1H_
zD#Iq{ZueA8l;TIb`kpn$X5SsBHj?FpV!HrYcY~@^RN}pDGk;X^V&G~0qorYaOP*rv
z^qN~4t3n!C(Ta6lUVkRto3S5$_!4xZm;=Uxwl-U<Orja{?I)@?ye14Ua3s@J^qz&i
zTUYxfEY%oSnNa@~J?cm|DotffTYULC)coI@p1I|aNNYEBPi)(dF9%FzKN#t%$af!R
zUz;Whrh@8z1eH^BhEB6)Uj67uUkXSlUSwJ{31@ZbXa{pKEzQRyUOB(&p>lXk<^TD!
zwrXx-kZ%7r>OqrnxrwlgbC>i*G{g?VCRx6GHc+-!v-|w+a<iH-TJOSkx#1?%8mlJP
z^Aj;oe_z;w_6U7y(<(Vi*=64R{A-Yspi%j&&bWzGIsU=rpmv>Mq(Z)3<$!sgDrNgW
zt{66;txYft&kQV}Qtm74k`-qO{C2WMU5|#0wUn?oyC~|ghKx56YPk5`Xp_O#x8g2M
X(5+n&l!#upArS?SL*BSr7fRay;V71Q

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ibasn0g08.png b/extern/libpng/contrib/pngsuite/ibasn0g08.png
new file mode 100644
index 0000000000000000000000000000000000000000..90b5305e651e5ced5480c9883807cb953dd4b631
GIT binary patch
literal 237
zcmV<J022R+P)<h;3K|Lk000e1NJLTq001BW001Be00001Ar=+B0002ANkl<ZILoz=
zT?)c55QLq&$Q(k%d-y}oB|eCFu&Ngk4<SojQ(uyY?n6Q;ou|n+n_*cjNFu5#8j>(o
zg^)y0Rjf!tRTURWiXSsGGZ7{d5<!yyuGv@;&e`M|+_DKdI%U%~L!om(qQ!x59KNH7
z?|Ar*;J#q*0sNP?25|S_=NId000$42<M()a@EyO$&Vwz=l6L9<UbTkUmnGfQ0c<L{
n$ozMB7t_9%F#jFa#T57ho4Nl*2CDy+00000NkvXXu0mjfFB4z4

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ibasn0g16.png b/extern/libpng/contrib/pngsuite/ibasn0g16.png
new file mode 100644
index 0000000000000000000000000000000000000000..c82f230eef51b9fa7c7c2340b83c43fabed1e764
GIT binary patch
literal 274
zcmeAS@N?(olHy`uVBq!ia0vp^3Lq>1Bp3_ZPW}bbH$7b(Lp+XeooL9{<RIYspQ$xW
zE3WZyfkgjv%@sQuMNg{Dy5Qrq@L9A%hxAQDpA-3Nlc#UD-^`~GxX5Lb`}~58PA2s^
zA0^Dh_q9tseqg4dW?6KFC1bv9vum%E-v6SQnK=f%?lq2V-2JZH(-r5RZ48Z2)_Lmd
z;LZA>(AgbGFk3R@N$)&7S#%Q5XTcM@9Nbw2&L*&W0Lcwj7XlewjB6OCC+s#bH_Ldm
zU-opY^%k+OJs$&hKidCZUu201*O6NXG+tzgbgVr%*RAn})C3R#6n^3!7dGQv=g;l8
Ri-4YF@O1TaS?83{1OOm-Y9Rms

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ibasn2c08.png b/extern/libpng/contrib/pngsuite/ibasn2c08.png
new file mode 100644
index 0000000000000000000000000000000000000000..05d4688853e9fccdffdda84797d221bed4af81f8
GIT binary patch
literal 299
zcmV+`0o4A9P)<h;3K|Lk000e1NJLTq001BW001Be0ssI3iyz%J0002;Nkl<ZNXONa
zL8=5H3`DEIdw3H)S<`bfy@}UoXtie14D@GO_*rBzQVTIYE5wA7fa4M+efFTF&mI8)
zj^h%g^TwPv=KRC-erI-|e~a4nbPn#)(>VfOFZBK`N@L-nZ4np?b8U;jSY*X*6&Pdm
zr^RjCo&!<==Kn=08-XIreNfp56v=WQ%vPY3GA)ZaXB%M5Xa=DA0+f;wn6{4##*FL$
zm5jYKjUN$=8QB3QYqy#@Z_XKNt-b(LO4fO3fc$ig!!H|9ip~a2p6_4d{L=<h^eqva
x<oP~=bA|j37@bSR)|xz5sI~sK0b`7=25;X@3NdM=1<(Kh002ovPDHLkV1i^HevkkF

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ibasn2c16.png b/extern/libpng/contrib/pngsuite/ibasn2c16.png
new file mode 100644
index 0000000000000000000000000000000000000000..399f1be5edd952a3eb0f2f6806a3ba7f1f9e2001
GIT binary patch
literal 558
zcmV+}0@3}6P)<h;3K|Lk000e1NJLTq001BW001Bm0ssI3+m8Wu0005?Nkl<ZSi{wp
zA#>v}6okLb7}(5Vp@D&gM_pFfzi>a{U<!TgVByiigM|r9|3P679!#0T_JFHIj_pK>
zrN$M|yxDo$x2v_so=6g`-vQQJFm+;z=1Pmi^c^68BDYQ$2%wlw-YTydi@Vm0#a(NL
zfj(wPZx#IA!O>o|ke#v7F}rPSp4NLyQ&*F<XRZ6_YO;~Zb}6}gfW#DTYqoJdFx%`+
zpF3b$4+ko@){_&uTKCu5Jka0TnsBc5BL``_g!c!4?E{>xmkvGqIxReNb6NEhmX`q2
zGSGk~DL|eAOkJJ}f70UtRcKPH&Kw;0lLF+~$txO0+LJ*z(nejaB>4ADg4bsWHa8MH
z|B>KnA;II51m#?UAHOB|K9k`7QGz0u;O3VE^HhSolmH}1%*zpH<z-^tyYSTYRY!2p
zNHMH~CUsB;UDSab^ivOZaE|)mU>S!RVEWV3fe*E32L9B}8C**3;9wZ_Ne3aQdmMzL
zZaD}|UDp$-TET7&&An<N7vifxJe_!2ME>5ySoN3P?9skwF+~Gpb-fvJ0{x-^(z3=!
zmVldR8y`Ue{-SOCN(l@TZR4MqKseDhe$oHXwM7GDw*cu&gaqP?K29KjfzK6f_YX+m
wdZGs;Fb>h435-v)LjvO#-IKuA5pCoD0i+b(v&J0Mc>n+a07*qoM6N<$g29LcCjbBd

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ibasn3p08.png b/extern/libpng/contrib/pngsuite/ibasn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..6df8370aaf812fad2c960360b5889449d79a8c7c
GIT binary patch
literal 1492
zcmXApdrXsO6o=2pMHIA93RYUVmAC~48?^)H1sAadH5)X;P7HA|GCL8R?bzrtWM;!l
z0V$$USC|?ZZt@KsWq_`f5i^N#MJ#H<+&(q&lFUh6!AORVo}G7Z@;v!HCwc#V>kI|?
z^TJi(05EUu8vQ%8NzB>70D|rtmjNIc3~#N^6X*^CL4Y7u1Xqv)$iqP{hj3N|SFQoj
zM1w{H(X0rrMhBo%fldc1Rs>h42heLkuLlh)f~z+I7}LOLgfvzJ*JuJTEe4Yb7PBI_
zCM$q-8Cb2bj1|GP+5l|1V6#CkD}rlt065lx!vX795nP7|AQpirLJ=#1E4lz&CE#*F
z2`hr@@&I^B!Q+8aRs`200Z8Q_Nl?y;;7UFKUnTf_P|1qm`T_ufY6t|Nniatfpdeta
zfGE_mBDjchIX1{?8dworM2!XyYiJI$BDjb;9k%LdT3HcXM7<u{^)&6Q2ri=0h@D27
zPF4gL(PY9N6HN~*f{SRiqT5R2W<_ujZ8p4Qqq)S2;37I4IP9PqW<_ujMG<d`G&flh
zTtt@(B^Qmvir^x8Jovyv^MDn>MU*5QmuSXW5nM!{51;vHp0Oghh=Bmk1ZZYh5nOC?
z-~SUJsA;W!)%rI)TfKS3u@JR)^wbU^w4$s+xF}PVjKBN8%b|bUcu2)*XWpWUvhm!m
z`*)q6evqTPJCM@WDZZLrB`dh6jEd2umc?ysYj68Dxo^roaxZbg!nBS@j$3UzH*b5t
zV$1fI&VBeK;lz7)Rz}Cg#w*mylSzB?h8CUP`Y=|r?$<PN`(LW8U$XnEreyYlk*t!>
z1Hu=pE+(JKdYsx(_9)J=@m7}g^{n2Wo?dm<cBwc&f5V2t!r`kK>FF8$A3M9d`=0#X
zTe8GriCekrlC3!<zfqO*+3;7+(xEZy9ryH8WqR=i^Jv>p!?E<{vnA(uL_|bHHramr
zx#qI{`0|H0J8pb;?dzr0*;;LC>e6Xx>6I%#?Z%6>`y(qWpH5CbjR=204^9s5>gfFU
zd9NtCp8v7r)WJjD-SzdN*wW&1?c28{v!*6Ec=hU(l+sd#qNqrx8*0za?(3_nnwpZy
z?Dm3!k&*h*O`C2@((RlTD{=<h?tz+JG5!BcPrnEY37Iu3G&F4go;~~0jy4=PP+xDi
z*VQ#PHZ(L9t}#@!9y-+0a`fnl6V1&I$B`q)&lV4Mb)7kL;X-?RPfus3+ufEsk=Scc
ze_~KRGbGOQMqLkidvxyA(V&dc@UzJ~yz_nDgm|y~xHs;4e2!N!;8oXnl`}~*S_sz8
zuGNOD*3MllyRQ`#+Bt`{p+(6zGUIibiXSu8m6^)!7*E&2SGuCV?^2Z~l{;mRor2mq
zr_~wS9ntR$t9C}dus~Sye)EESbIfJ)!k5j_A0;Tw@?++>4d&Rfq%lkI5=+E+OPJLX
zIXSy&BBXF)?zM@a*OGtmt9JV5|Lspm^vfsX-}Ea6{p#I*CHfP`>H<+}h4~=;*|0XR
LKz}ZG^Oyety+*k>

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ibasn4a08.png b/extern/libpng/contrib/pngsuite/ibasn4a08.png
new file mode 100644
index 0000000000000000000000000000000000000000..bda8e3c651733475ea99f7f70f919fec04dcc369
GIT binary patch
literal 198
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnE!oa||uB7QDkkjkw;uzv_{B6G@SBn9UYy1N4
zyQO&-<c`YSS!_|vRQhzA-W0CVHlB_}NlqCa|NsA-$RXO8khLtrTu9dOu*riD-pk~R
zUYu`qnf-&W-~9cYq7x2L8zSN&m*yRHn0$xv!_C^(Bad!>^`7Y$eKEVi{h^gwYD3aF
yqw4=Nr@Ug*y&@gbC~dLhAZLHGvBeE71Ex3rww&tW&n$orWAJqKb6Mw<&;$U)flfyN

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ibasn4a16.png b/extern/libpng/contrib/pngsuite/ibasn4a16.png
new file mode 100644
index 0000000000000000000000000000000000000000..500f9128e6e7e864b3a931849907a290825979bd
GIT binary patch
literal 2839
zcmV+y3+VKTP)<h;3K|Lk000e1NJLTq001BW001Bm1ONa5{^VY&000W!Nkl<ZSi_B%
ze{fXSb;mziJxOnO(dzB45JEB%Pl(@ypcot+ga#Hh(9~uL;~H=V6VaMxrZf(YViNS6
z={Qf+HFii`;;Hc<#zPaZV>g!L)UG2f4l6J=4p4#(2+)EAvXHcTS1ax6t#q~OA5Tm&
zZ9J1dzH`ppKkj_bx#xV(x!C~bO!&>~VAnvFITMT<ralmdB}*)Wkro(;n>viN3hTRv
zvh5o9_Li#WZ{Cau%@5fj4SqfkHXeXW_kl8PG~_?ADWrA$H!S0goyyC9fY0`aG<BY3
z1eU&WLs{Pk56ypLXJ;qk$^ys=X%G=1{}vBy@j~b{98JQ}6kK@AG8A(r^xuY0p9pE|
ze-P5H?uSFWE#uK>L_B#ZB3zaMcUqyN1D1DLhN@e}=^4=334M)_RrMTn4OBh9u@5%(
z!^-c#e@=DqtErHss}R!u2+M$o_#+hMmhS%WC0(uX!iWbF{{dH%(3XVCx6jrq541zu
zHeEfwO;^`G1Dyr%>+i$8*=Os&bQqyL&<;y_pydy`dg>`%ediiHlykOz>5mY_`#`zB
z3#1Fy9)S}=SASGt88e?o<jn?U1eCYuz_lP8I|oMD+4`T4VPD@3wR@nf4wSd&LQ4g#
zI&`*v-d7QxPB`-nH2n+QzYwwlDc!wrk7jP{gN=Poa_;6~?2(wArK=FLb@%Lkm=pj1
z2&SMtIElhP@q;kYY#B;OgPz~P&6jlbHx0VldkaRh!7~OWLr`EtzsHH=;}ZC&6f%!n
z#=?S_UHYkID<KUM?J(el?hoP0HeLN$tF9)BVEQ!hKL_XTI7vwV!ZKEk#O(4PTXs=B
z6f}Vn(m=MuSU#jbg5)zWupKU!>greD)z#MoT#Z_WQ5&;MzG>OMZg4k3ZXYOzL9q-N
z?F2gl!|Pz618#l~B2UAP$1J0w0uH_m-a1&+1k)Bk!C`Q}4|y6W5dmT@^t}T&zYG_?
z205!OBkZzRzZWrcI~@8~XwJa?-B7&(X77RNQz5t&vNj%o?y&Ce*ruzla?PxY!jdRd
zoq(z+6mN&~E8*Oq;Cv0tOUCT7S7Wvk5s=kp8MEHDsN8^<wF_pAL-9WFghAN~+Ic8z
zhOuT)zXe52aQzW@uNks56Lj_SAq<GwpARK#mezPP>^Jk`FeMKDI3)X>#7@LP{w<6I
zArXXl5PE{p6@*wJ=xS`lH7g7*Q!_iZ>FO<8SNndVtAq1()jpxCnMZVWEMHfX-_zBB
z>$=)gtE)F(*VU_qx;nexVW?DY0QUm8TCSOw7x+!zvoP(p^Q4($koJM~5_FfswRX68
z4=ieo+2wI4RzaB+2H$y@5`|9|YUTySZx+=;Wi7~WL9zorYk@02gEOtL>{iUKoCC$H
zA$a$K!c!28g8vEly<0O+&+(hH(=hrm4AjFXcc7&gYS+Z<xwoNYF9hP?Q^8fa0p_Qi
zcdxF7a2t3wYi8tWT^;(hu3j$H)g!&Sy0r*uYvI1z@P$UFQ}w$HWE4iDF!C5Iei)WU
zpk=jYo?GcRzkL8+SQoSB-G)FdcuzxKBjm(EQ9%hDgUpMN$%pYWkdH$7DyY~2OP6Wp
zYp)8UDhm0#Ah!aP_rSFoT)%)U6O?OjLR!GcN*Fu_cdFsy{jh%-e0(NmA3TV0_&7%B
zJ}7U2Kq*XV0JR2kZOC3*uCBSg(67WU`;|{d{YqP{UwLJPU)gm^$iF%%WbP6nk3VJC
z{Qg5bGI~bH<X40oUMFNSDP%Gur0aS!T=F<g($)rVRm1wWn7t?(v)%8<?2=H-u2~ba
z)0ZrxrNvRCiw%yv#car)bxvJ#Bgd~?^7xgHp7tx%D}=n)7IMM8Le6|#Nc)zMi4q}Y
zhmbdJ*fm|>w<DSPLXP=_9PJcRx!w$&o8WQ{EIARgXGftV3IzusI|}Y5C|n8UKL%?h
zoO>MO;!TXyD==(>a=jU@Z+H4zPr>vu@P8fLNpKB8ZaesHL(y9>V>JwW;nH%9_8>;u
zhHUGKx@J~bNL>n9HebklHVIjrE#%ZCLI$@Anf@Cghd&ZBbx6qcppddn$jpmE4m8^}
zR-YZo(o7JB*62S9fn#vj{-r*^z-9;5mcQJ$wt!}e21QpP5e6&lH?MEe%t8}}8(`!D
zq%$yn9wv@}Yd7RHfO--<!m0kuiw*(V2<df@ngK&!gTdVpKLY)Y(DyL(FMz&H&~HM2
zGX#zbV^-KQd@3lq3d3PY#6cus;6cB6*{hkN4u&p)eH_MS!o+isT?ct};9Uiybx!vH
zjLw0PRgh=`>j~&R3_VTIa~wXq1U-Y$<AtJ-Fy<vKLyLni3{z5*1X5v0cEOMegL`3M
z6ndBV&GSCZ9GC$^{{`ubF!4oD`oVJy3d)?;1xEu0*Ft|Mbbk>#pKz9>&NOt^KuJOv
zOX@5mkP8JV$d7|J44z+25=d`=k$;Ai2FXT9EC*{U^sj*KZok=fQZwhyh2aMwvmNsO
z4z%TtZh#Z{op<5JA-LQGSDN6;NvP0;QN6-43U7ly3cl0e{WtK$!TnE=_Yac<#=<b#
z59#S(H^Ru1F#KgmRKvgk^lXD0ANb9;sx`B>3&y%2KjMfMKz9T#u7nRBfzvZ!@jhX!
zZ?lZzS0E5@+Gt7?+|PoVg1mmn4MWb|8W<15_-{cbK|T*-QAlqFyBbm{7&-|9)1mtm
zTwd)r_g~Y@<YSIv0<;`-wuis26vnPomQivI0w*EA7CatMZ$VxZa`uAqT~OkX9fs^H
zlLXiR6PsZo1rv=h@gz*V1DP;nGLZQu$el3u0odzca2s@V_|2uuG!x*pSB0@-hh-GJ
z0_q2lvj~)5g6r?W<pS4>kQIfj0?4`rS#ikP0Q?jbVL)axWIT{*gz<-9`~t|iFxCm9
zqhL2dD&*`4J->yElM%o6sxSZ^-UK@ygGF6Xyb`o}@I*lEfZSZj@qy9=*^43jb#Sen
zoGAt<F&ktvjO~OmFN`*TeE>#sAlU|q1PmO8&jeik3Y^~Lr22(*f~u(V1TU<EcaCEm
zyavl(hS_&u`U(itfzJotQg9c6x)XA%AtwkqM?sO31kx>#J_oi3QVlR%1Bp(sehIz3
z&{geJ_Tpp0*jgl5{6m<x&zX_{^Xeh}Lny3=|2c+nq!;Es05e*ks0jSu0biLj2t8*&
z4MN_VkXJiNV5AvRRgm<+&>j#6p#Oci(*~VgPCM1E5mdB8#V#n%gFurrqQUXYJ79bl
zxZ9y<4RjpGXo*4D44AghnMhhU<bMOaLGUz#+nywlY=)s)NO-|&fc|UHbB`k+%Myap
zAt+5i=@3j$Kp^2P7s`7M0k01N`7kmUGRq(*AEx*qm=Cvo7-xJ?TnB}f;O_%p5b~SB
zdzV1sO&Cmp<$?YNM=}>R3W`33X(1<~qBSrz1pX~BWewzooI(P~YlSKAg1;3;TVWys
zN-MZq9lZ!NLT@X^#lujz2mC=OcoTdjlfOlASZlPl_{~7d`4t66KF9u<Gk~}U;_m-r
z|J>Q69q@qvsAXt%q9I#IP^;|7^ix6>=L<RQAt9%h3ORMVkimIE1|AnuyH7~%DItBe
zLgqg!r1$GWdjDNW_ckH3W(YZYK*+HNg&f~2<oGHfCw?F#UlP*wk3zaCg;X9DGH05Q
pc^ibxa|`J{A>_yx>`2dh@V`j`6FKV(<2(QW002ovPDHLkV1gU3F8Tlf

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ibasn6a08.png b/extern/libpng/contrib/pngsuite/ibasn6a08.png
new file mode 100644
index 0000000000000000000000000000000000000000..258f94050cc0829903c7ebb7224f4f6177559f1c
GIT binary patch
literal 339
zcmV-Z0j&OsP)<h;3K|Lk000e1NJLTq001BW001Be1^@s71bs?k0003RNkl<ZSi{wo
zK}y6x5Jg`@i9Ne<?ZS8sHxuVrZjzt}OVEo9cnSwnZgiN8AtnAmV?ooT^7H%it5Thu
z4Dbl-fxY1)=V4cTOcNtMNhBv%-{1e4qqzpCfcv>+T|4Ex414Bj88CM3A|N?=J9G9)
zlhOF{5wroIBLKW`Tn0Ez1ZV?5xA>mqy9}`XS~tP|BNy5bg$=bx&>|AN@}Ln!Wrzue
zS|rc}ker<PWzFYyW2Y%F)IOjttzgguV7=PPy{h0Xm`Ndli;ZB2bu?EAbOmA~7`;f~
zB0=)I43IC@CU{;8vyuO1HRNfqf`Gyf9IC<&sN--20cE4S1Ml3H6`)RYS%7*Q{C@}h
lP?Z&+UWd8^r3I9B;1hyMQ}iYNCDs4{002ovPDHLkV1jJljxqoM

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/ibasn6a16.png b/extern/libpng/contrib/pngsuite/ibasn6a16.png
new file mode 100644
index 0000000000000000000000000000000000000000..e4de69fef1d63a762c4d8d782ee68e9fd7c33d62
GIT binary patch
literal 4164
zcmV-K5WDY*P)<h;3K|Lk000e1NJLTq001BW001Bm1^@s7RPB}_000mRNkl<ZXx`nK
ze{@vUoxnfyi}{sF<|ROANWh7pcp4~>qYEO?h7x~t1+;=e_qam4wu-PS&<c6yY<rxb
zdr+i;u38C{vq%<Eq1x32lU+cN?HX`}wo)-qAch2zyq8R7<_`1Y?H~7!B<y<JJ>5U{
z>>qPJ=iYbUz29H=`+fJ0!?tZ3pv44$7HcT6?dD!d+lFZ5r$3Pd%PJ~dxyALfpH=)w
z4&C<@)M#^S=hoWx%2xmzS}bgP`Y`~@f}+BeTOR)@Jh^V=7CGz6EsnN?lEL~)8BVN$
z8g2hRxpwu`ybK?HSUq*hGj7-!2l(#X*gH@YZmo5PH%v2i@Rub!UjN(;I}-rEdE2<{
zd$+y*@J%z|`ZZYZAD$2&UJDM}ZcE6;B7UgRPOg=$6ZMk+sjX<dk~kQcY3lCF;s$a6
zRqI9^ftqj?-<=CJ;T5;Yr*D<EZzzA%)ZyQ+`PQix3(Tvvwiav91TmLn$KwF)8(M42
zA2oINba?Co`Q*_J05{Ee|9yZFdoC^jhi#8K0+2Y^d1GMalxO}BgzMt)hX7oc7{n|3
zKMBHw1USsK(hr7Ey8RF74mb4rA>tq1T%3f6&s0WpD`TY;dsP2f)fPraw5<NvDmVPG
z1YqQxF(HWfuG(1^gNX0+emSsjg5)0`l8jrYmydhy*eW=G^c&N#ocRghx1#|nD?eTZ
z5nn|OKu!4gEJ@Qk+&!Zt9EIaEryK-0y=UA4a9^Gv=a4+y1#s*5GYcW&JAI9&z4W4~
zL->I8Z7gsd$j%0EzLC3g$OOFs6)NWeUfb2Rf8kxnR!utxlb%2vt+;ln<_4&o*>(t^
zsIsq3PB2`)*roxTI1$@EvFg~W?rs=99INst(Dt{`QE{sArkQZ|T;Gx@?*WuQ-@a^+
z1ZQtfHjH`q*s6{ol*O@90q`cEpa2F2VC?td%<GT{bZ)&a0p06TwO7vvhi&H_7jA%v
zzt^warWES=Q`=wBpKK6Sz7wYIz8q2oB>=_AqFoU26*F=UM0~-JeCo0#(@wQ<yhB}=
z@C@}thkEaeLN)%$f#U^}O&xk4FMi4p(7&f}fhh(F;8o7_D~p8M0m@<}haloBqp}hr
zKJO|u;cCgxRr|bZpH%Ix?LG5K_L@3$G?djF0{Uha9Wn*PYlHg$#9rTg7$ksG3E*6#
z_EJ>Rqqc;90l=iEhxbFoH;G%vL&Ud8y}kcit*zBlO&!`ktE@Bx#BK_`Zwg2q^4<iH
zndv?RkPWyJ0J*)+p#o%;02#GeFO5^)dQZ}tE@>P9Xl*@xP4!e$*ED$G0r}*C9|24|
zceET}<md|>00qwvJOtpKnK}gE`8+)qz_lm4V2A)h2@t<mvhT1m<_>_KdFJkty{7(2
zBTQIoa;h1wor4uV0M@r*-uv+D8E~rcXvMWZhf|F(?FRs3D$bq-D1NZ_MS#%7*a!gs
z-sDgV#KuaR^#B9M<3_<`Q}1kqQA<raTVPZT*7+9r#&;n8&k+0$xDG&eHk33%&r+y7
z2yL^#e-M&0p>ylmbEB3(=hm~cCLaPAzP7soplEO3U;#vxc-D8q)O+ioxXDBk%RCC&
zH0b>~6#oqj%z%O;klqZQ<=}h+a(9C7#~@yWq65%38?vXtH4fa*LuMHSdm&y7y>;E|
zicf&KxSOl%f#iF#9-N;h`TMsek4%>Q&2GsZ6C^kPy=3$%$(652{$P~kotq_V!je;-
zmW=o$!%<spXi0}{C%*~dhGf)t613=_nqa=JozD|s)rX@-(ha?J0De7u5W-QdEienT
zXu4U2=DR91RokuTXpzjRc7A+P^$+Y;p{)9QTk;F{`im2WfWF?MVsO~@iBDx3E?fo?
z9~3_Y5npUw!4%M<`Aqi36`AcT`>$ws6y_Jc&^)rn5YV@%XqO>i;QoSbM$!%DVmTo7
zqU5DUfY90zQ3yv%&7vaEqVYB*|7ViUe^Z*P{sF}v#SSCCa7U=D-w@Edym%A9fWIIK
zkkA8BaOPbAa&tiER!O;gHLYhJgrns>GL*tmN!Mt}<X*`Ow@9`blF-&x8IiUa-LEV#
zM@B<Q0>IM4Lj|~~1UTQQ1UMu4Nh3gMZTkiYM<cW40^V08y9*^hUY%d~<5iQ^gG|ZN
zDWhWmT`i?GGAv7y0H&@*VUP=)V<cTYD%@_D?E1Yj<y8RVHdVGlI67)qbv0<wcka%c
z`kha29cKvWUOjw0Kyr_NK0vzA(+`kocFzIG1)Q=L=uRm>-U9ab6jh<MH>x;)Q+a!v
z<a;jxEL`;RFCiS|?uB>l`UgvgQA?%sysxJ20dSRNzW{KCaxnl$vpomE;kT0j=nNGg
z`?y-@DixGxRd^|vT&R#d`b&V9UxEkz$`I94U)x=IHG1o@akHk3Lx;#}V?99l2}=j?
z7bg1whP7O(0dSAaoB?p@*`Y2-?T{3z>cvV`Y$yRvH3A$hhiT^w5wC#YIjF3Jw$Gqz
z_URSVBk1kV#^z4C9UaPh+Dib!Rn|#>KyzXafNz=D4B*kz|Mf2TG6>HOUij1&xOS-_
zE{uhdXAF_v2A=y35sE<Ub3=^X4rlH&M9JQ+{qD`C4sC5igK*F;NM7CrgIqA6!pVAA
zZO3zYF~(FF;^MV1;uH)#1O?AS?hSC>0p1v-3LyMvU>$|Bdgy3?OrdFwaiaJ2X9`F6
zqeH62TLVxS=uZFy9!YEj=VccR%>$i{Flvb*dhdne9fpXNLa56Sso#OO$`JN1!10J7
z-18vwmLUQGNF)qV^a1ouH^hi2T+|IwFgf<5<5p82WC8zR3k-I_y1W>}*BZil7{Z$k
z5xWyYZx}*M2j2&VNRI{2=Z3Jo;7A$5)dSfQLwHX@YN8>6`ygIxh@x%KcfTQupMu`U
z4H1|bHyrJzemN0ckq68=&~_T4uMUcuV8Dg~2P8iR|0Efr-g_at7+gESt^-Gt%pSS3
z;OU2SA@~l1m;r$oA@O4<Tnzm?AyWtLCdj>zY$$F*7ZdFd!oQ&2VcYp{KHnS&H;5|P
zN`4K+#Q)y7|7+v(<3Kd~YOH#PZJ(beJG^6MRrXbZ76rc!;b`KZe403<cttz@75(}4
zS3b|b|Gzc=*Q^7{sK4IQL7enenL4D-c*k1xZZLH@U|3oiLe+C$13+Mwe=%s$z^q^;
zgrftusnN$J-P<HxA4xh?e@-!@m{yfFU+5eu$$Z_(pGm$f1M2oFpOxcko`DgHm5M57
z4dkDHlvg<37K~UrBzO83n>vVqF9DFM^ELro@(fFZ8!Tl2&nJo-lp$2Vcci5MUjPcG
z1Uo^C7EB4Pg>ba5PZ>nfrAU`Dg!%$ae^V(`t_(0s8DOI_lzK0vm{6Bj`Et~!43S^&
zOZMj#j;#x=v2=)!3U-=0B(r`OK&ru850HAsyAmM1*s~KLJ;C#dOhQUg_uGm}WRFVA
z!_>E|w_QbssuzK?07XTi5NOe&B29yEv}c}rYraxcF{>yPop&k&sqrb*KkyflmTGrj
z!Jhefg-ufnTROyIp^&LVqA<`8Ah!CJ0Hn&L#FrX|)dQpho&-Rq&fNr%`E&Q%Ln6Sr
zai|a7$^dS48{t;x)L}=IK~$yot5Zk8M*t<i4p)E{Eupj)!qK3LCzsj+sjHOd?pKkq
zP5DoayPyuI?e{4@tMqN`+E+T)(!n|xt}t~Nm@HRJCZz<akT(W!sd3m+fXoajab~}J
zE<ol5_k#f0I#&}w?h)t4AratI1=+D(wUq&!H!2m>hq~)}We}y3M_tQ!)hCQUCK>7l
zD1U7D9iT<a9~-v`!ckAF@}Dw5T+Q01GEZwo-ovMtk9*G2q5I9@cbGcFisg*SkX#}4
z*WQf)>9mv}Q|Rso$ZmBl0mwGH<mc}Z=X8Kvz?lTF7dv(W<Tg2%4~YQO2LWmeIM%85
zW2&tbWR7a9oZ)Z`eeV3NGSmyoP^XoFUIM7D)-=$f)zu3ZK{%R!8(!PB@GeUS)6_Im
zhtz5BIDkxr`y4>_Avt622DyU$regtsZOb|A8yxbO*2q!-yVN1`&<3f2z16Wq>DdHa
z{v6LofIVJOdDK=BVDFO5DPQH(u`{Q(KsGCx*&><#m84K<E}xe#ysUhDOsdP>3-7Y@
zg?GWih49*LShxtFdTMJcz{vg!g#ZPUWrp{y5>Eqo{!*^swlYNkE|-+RIVaZw;M|&9
z0^t0++=Bp)2D=_EpF<pVb`yZ3+HM^Z0XenTv;U~t$^coVXhs#R^b?AzKcxy<QYji!
z=bGLQ$@bkcpkdr|mj3Aq82_9_=T;cC6h^Ip&gbCPkKmmt@ac-yW8=4>pI!mgn*hph
zZ+{D*cy;f3fY4KN1^?vaaR9GZO5iC>_XBv=r&j^En=^9&T%Tsg12~&<bpWp0q=wF1
z&N(CkvT7G*R8q?*1EfbwUQ&fDU#NsKKs+wlr?!C1(_Q<Zbgrd$?Ss-<i>?DuIvcum
z7#@YxJ>Y#+{!;hA@P6nngv@MkAArDmNUVaceeKVd)}nXqZ)ehD03~~6r73!(ZzDi3
zC?)WPL=3>YHMJCA*zcsoo-d>ZZhs~T;I7Lw0k|r&Z9^g;y-zV;xs?G@-&YE&y`8vU
zDXt74E3s)ZUkh8hX@aI%m?fa~fO#`$?}Bv$g#Q(id%!;*vL?7RaFs#!3)z?41K}s6
zM79YI4Ll~Kiy;_+cpI2z&wTAy=%&>}r3O$`D8C7Uh4FrXz}CbP0AEam0KBhD4Lp0(
z^8q|{=_UYAZF-+Pjwu7=k7fDGw2LYUUQl;ioyx=VswuXvuRpZL(mO&>)^CWe9Z-6&
zA$n#)$st2nCm~#Ah=Ju$u-Onv5BM{NNN)kp4-JvK9-JQ<!ucWOt~Z3|hmhW42!95W
z9zzsthJodV2v>o1(hwzwpl7BbO7DfP9fm0DhmMdTLTmc^ozGi3bQG4wq@1IcO1b6n
z@8Y@<Yo%W5HfFK569%2e@)3|)sXVPBK&S|iU(@k62u3VDZa^?%5g!4;ix6K9!A%f9
z48a)?FNa_|Bv#8XP8#5kz@;`ARtXth-u>Gr!BHiD_DR{7(P5YYmm=V=hGZ*b4RA%k
zHoy@9=M2al2KOe&EC=sJNR0r04J4Z(ZVY@BjG)Jj0Y**%2&CozC%%6YHv{<UL=%8l
zPeq4BK>l1TuTPWF#36sZrT6-wIAI8L4`>Sv(YFYSb{V2S1BGrw3~Yyj`wS7k1%mGy
zB58tOGlbX-zGa3;-w2)~hRB=&_gF*Zo&@I_L)a6+al#Oe6JSp?gmVq#o-~AeEM(3Y
z!gB=DHyXmX48&$b_%%qHh6uh3@mma0a32h8H$<Tu`ZI<o+68@!452LmbB`g46VU57
zgugy<$Z^opp*K*RlzJ97U5)@p{<2y$gRcfe%TOj;q;;?C|9|m(4*Ulh3-3uN?&8n@
O0000<MNUMnLSTX;;lBz1

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftbbn2c16.png b/extern/libpng/contrib/pngsuite/iftbbn2c16.png
new file mode 100644
index 0000000000000000000000000000000000000000..64a9cdf2f7fb4015cfededee285d015f96330cc7
GIT binary patch
literal 2624
zcmW;Odpy&79{}+0hMu{k(M};WMJ>4<_rok=GIGCPva%4Wg9urf`~5cIkuc<zP$W+&
zCC6D(%#mv@r?Z^7-{lsb@4R2H{eJ&!-+g|c%RWoAvbb<iKtccjaFAqTWCQP5?hB2C
z*Cz?T{ta&jf@~~o_x2UOF;fMAe~n~hVCU4<=hXT8VaKEA)TAx(=^L4YT|CUh!_2NW
z8Gf1At2`$526on^j})ph<R$p4o|YynIbH3Dpbb8~Vy!QK$lhK)#^@ho#KV6tiR!+n
zn$w}Mz46lN%)-qhxu_-?U*z2Sny#Rq`oJsBx-KWAOD{x)XpJF8?zy(@4S?Nj-uK`9
zwI%QUm>p{H?yeuYu9?5XL7|Vg@G%1<nPJ?M)U>#crW%*_;D~afi81aAE1Og)sZ&`U
zR~u4OQc?!zPC~{MKR>^j_;9AM3s04ue732g5?6`X_RhVx<Cf@6Dxt0yUW(k`wzRa=
z+Q`{<TrCCy;G;pX2A~b4ToEhp`JbDTqiyfx<YZ-^4uL=z8<`D!=?0G~v)Q@9`=W^}
zH-`&7`FUTUGlpng>P#k+2WGT1H8r0PTj4MzK71Itd_F#GHc|+i?<t;RUIrgaG5_w`
zbYFGgZ~33S&IqW0TtN(N+LtcdQBxy$RLRX>J1#yxK760<zUs$ZKZp!?q(JP%zF024
zqHfO0=En&bTY06E!V$`U+uPfTIhSA*-eS*iNkTjVAh3r8fIc07XJVIuWIQ6S-D3?Z
zxuzl})P4fyHtjS$F{Xo8fQCbY4JsRw?<+Qp7q05_ZFEVk?-}Dt`w$e&B`$Ozx^+<)
zX~H~ooIu@JEXJauuy(b>*KMJinq;%&<T6nl&=wY>VV??h8kfey_bGIGH4M!LDJd%}
zYiaNyBSGiKBn3yuXrvX6@dODL@t47pHV*Xmip5<Snk_TSRmzk#?_HfYS;2R&P~pRn
z$>Z(GN0r@QCyebCC#>Ch<6d`~M3*HcmEe;0i^88tDjWX#_3JNklEU#}h2=gvl7ztT
zA2LHnU{7KAm`hrEilPBJ1r`swV6wWp8XFrma?hesyr2FJ(kbYlf^|Jp1dmK%e)ei`
z&e`7D+ESOu@f<S6!*3|r*jk$zs3XHvQwih!TrVnO{#gpeOTP_Z|CxGBE8{w<<Z%)f
zmn3_}6oy4-8Mk{pb5f9g<T^W$F>Z7s(?nJ^@8YSfGxlQd`&ld&?T@Vrp=*sUH4bM<
zfF88{Vu-qZ8_VcBfQ*h#Qq|Vh%&|yM6;D;ap<XfvYpaxNn0?ENksWE+jZ%tA^GJV<
zH8qjSW{n$wKHatq*|rVpk>u_QTw|lar><9S4GoHlYHEs#hK7W37Mh;db4^_$^#fws
z(WGiyhIR!ed2&yZ8Bq1*=g*(i@MhRT!MA<YCCp{HF}E^c*}WPn6G9eN(xNYxaz7k*
z1|xPV_i&8lAsQPrG+1zEXP4OS3rp<mB||Bm%&L6`70MsG=S@y-%DnVa%}Y@@7q<Mp
z<0x6yw&Rh5puoHCbDY562w7p9%M)e=!pwlzZpJ&_TEihJqS|R}ZHwMbyg3gF3G`L@
z(L()we9@T+t>{E7ZWFIhh*&6exw|k{psNth5$>+;!;@XPzJB3~u}Qyeyo`!HUu>1Y
z32U+PZyuemduvfn?>KouAK~QO8X#Fz#8eS-Z~#2GBiy;={|E49n8k_k#vwj%5a8b4
zUGKiR`APp~kw|8`c{ww^;$FQ=MR|F-Kh<}-zs6>&U-5a;EA5Z`Hn(5{RrFp9rcfyC
z)hWfBeu4&MSKBJP$3^!ZS65f(=fT{DZPGoRG;<qVYWh7y3Jz?apt=3^9Lrj@SV%Jh
zR+{dwula>9ok!cr8=#3K(e?rnnSuih9H|87nJY8I@HRm6*4*~=^qg4fMgUcD_=B@G
z-`om?zJ{R>+^q0<@ZxJegh-Rpz5V269(VqJ5JAB$j2sHX$LK`>-e>@Na5NnK5zfLg
z>-%aDoY7b$P2prLPi0?HiNgXB%q_qfDx#hs*(8=5AU3|m!<KePqlm>7S8hV-grs(l
zrMeaunB`*<(_C|-)#9_H%cprh&^wyW(>-aN?%pX*_t|2{-4m>Oh0gkvLTlIip3Vmr
zw|91JE39Vuqp%}4YaFWEpXNcf6|lFSl<|Sfx3WB)f8>&1H8(d)rSYKkMTa}|t9XHa
zFTngFWP{Pi3%?6EBFMaPBiq!~6-+D(2T3|&B<o^!IbCdj6rX{9)~At&a5;E46kFl$
zn<kdv{$v9neF*5wm-S8sl??WBtw{3<#5VD+-T}>e=%-&prdxga7PsX(7REaapP}B>
zC%v!FW{HU3N5I~*OQ>uL!^0hNzq{H_-d;V4t=-bd2N*p7tgfxCudi!qstUEKd_tfY
z^VVdty*>F5mINwAh2pOMby-EC?MkW08|(Y$4G>mng!67`Xoh`ZIb1uj9_h5*ANlTe
z14jikAi7bnE@h-63jjeuLntD6YG}pOr%6kFaLzaQS>-7}ai&qF+m^#}&x!@TyghtY
zq9r4Sd*n$3Cfq266DEC->RxAB_TJMOPNk__6gHu_ShA?|pfD2r;ejFgh$bFBZShb{
zEYuR2t4wa8ZZ5CQXlM-79hY*tq<80e#f6;kJHx{#GGA!YQ;bYR8MX6@2qJ>vLoA*$
zMP?tgqsyMjLI6}eEFFvGrCL*4TPv*_r#d<~IJmL19<ng@W_u#HZQlY397H+RQhy9(
zpVj*P-qzITd<8RWg=988hHc@kG8u$qbp6!i(N^lzC8j(H`~q9c*_8(*7$>)Th%oh}
z(<@3#?Ub^Y!#ZV>CzjY3(xvqtJj92?-JgCg?(Seqiz!2JtkG|v_EIxk9oIEoL)NPu
zM@My8<6in>p4p<@aSPv-WcuSJ>@gGO?YzhWse*!H)+(emz6y)BFuFFL1yt3)xxKl=
z-L@1;TN{O<d5k&a0>bkVQ5l|5gJ$R9GRx@f8yFba+n@voYaBy8B;4J4ZlR^7rnWNI
zqzI*^ZZo52-xb+grR#*ukG#CadDumc2-Z1$YGgi<zp(pi=-4-gPkgD{pJN%rFYRTJ
zl?EqGPg@q^!&WE1bIH<Y3^K90i{9CzamLTL*B8d$MjSVPkRbcOmnTvmi%#IK3ZYF2
zDK5Q;-JhE)oSq26AKT;lKzx`p)mvd%L<nvkz1ei^lJjfWPBX+N#USx>xBmT<r{+x<
zVUJ&A{AKm!I6ido@7CzPeTn-bp|{gBdjiN0thIC8{X>H3f9AByue^ti+)LZ}&)tId
WtY3e({0;sk1SFz`QSJH5QU3=T4Dpo!

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftbbn3p08.png b/extern/libpng/contrib/pngsuite/iftbbn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..47d6eeb3c0f2f0133d6a3e248e9d6103398177da
GIT binary patch
literal 1507
zcmW;KX*d)J7{Kv&W-uA7DMyEPqok;zaV*hTJcA)2!_1D@MNA?`%;6jn!<c2<_mw6|
zB2zl79=94%TW&3t7Ex%CY<TR{hxd6uydT~Vzdz5}(N+Po2Lk{Kb|j*UWUGIhZ72YQ
z!PO>b0OV_D2UqK@t*v+O-igKHrKP2rnVH7M2OJK^&(F`7LgQ*_Ra;rL#KwLYA75Bl
zXlZHT@p$LXoeTH$j4(IntEi*{Bm!IlC;+&sqcb)zu(7ex+1Z(!n;RAu77`ek4NwLU
zp{N*w!<|N>vt(qV==6$;is#RtudS^W6&0~qtnl#gYXBmEUVw)H!NI}B#l^k7y>W4I
zOeQne(D1(Gs;DS%a%xalp8)s(5D*YBKK>>tDJdl-B{4BEIy(9ig%ZJJvf1qTz`%YC
zX6}a{LPJA6JUm=nT;}HH;^X6!Qj*fs(<37zeSCb}+}xa<ogEw;I0+ohd`%F7S*aO6
zm!F-TEf5HzqN1o&Dv3m*(P*iusc;9N8(<miTkW&5vhwrub8>Q$lapg&Vh$gUk&?>C
zVxzUSDK<8wgoFgyTe9#7U<H(>lrl3j3kwVRe12?fESc<u#Wn$m0WtyntE;Q!ugJqR
zuqs)^N+Rh7NpM|IR#sM0QsVCJPNmZ1<p%*i0hA+=o@lfMfRCCQt$(Orqd)_00z3g|
z2DkybIl85#rRC-2y1Lf^ws!B<QBvBA!BC8iDNqSe2k`GV8<PSP27}?~7>GoEMxlaC
zO)XVbExWtB4U-I^0U!<F8Jx^J36Fu0O#l#TXwWPzPnDEhv5K(zruz`EnOMjNS=j|V
z-s?MQGzQ}Z$p9k&lFuCgc~DSL;O*^ABu0E^3|w7Zwe`2fv2oA_&;^hMl2~v!S0vIG
zfd~O84hRhZK0piP<>l?zQHRIlm6d}e)I6RbEiDahgCX6J$RolZK+GgkC=`IwuV24<
z`+Af4WRNt$0}7Aw@#9A>m+Kki3E)d6ljr9bot&H&7Z*>TKE1iQnURs9v~@ueCm<Lu
zj%2Wy9-&LR7ugXlT}_^z^#WA5?oJu5aQcD_clZT%yG-;>V?A!J932YvCK99~q^%EH
zFgOhwXDr+lP#sfagTpl;mahA}Eu=TvE3+(mhF-LHjf+uFbR2NFo7FP<lw`H;pjxDU
zd)*U{mWyh_wT05<LTnJLmP9|M-%+@yXsiU&6lGfCvtP#jrF#5dpGat1^^{eCY&uGN
zw!GkPlgJwP4=X)|cdl6=&#cZX5*QDr-ZxA=j&9?gpoz^F?eSZmAJHC#US4+`Rf`F=
zWSSj7AzBmL-zi~tY*(7eOXxW-Tl4<?tlW{*aDTO>gyw(V_|ATuoSW8tJ2@#vD{qtK
zr-VtFjcXlN6&}1+arl<7v!L%<v&a;!>1=T2nBU8s^DizMG|~GIvbDc9(&w8#lNG8$
zMg|`4)_g;#Uu|vsTx3gMSvbx?UI-ZxZ&HV=x)~RmBKJ;aR9*k?RhhMn`2<r=wW@wX
z^8_E`F?N<8y564QQm^LZ9J4$o*LVNWHfc1awY{hNS(~`4@3MB+QQUzehdQ<E)%B{X
zg|)RuYbtB1>JZsR`a}A7{NS*WfpO#QyCTuOdoTNUW*Z=oYNu`^L(uzv|Alil&b2}X
zyGywjiQjLof!986t!0EGpfJ7!gFB+|u;mJta8PSNWysdX(C}xY`)duOckeZ_87$_P
zl~qfX+m3~1^}!rsN2j#hnWF2s)HBV(v$LX+spFz!RQq6BBlFe9{9B&cP~aX%75`VG
z4Gikg0wJ2(s!S>^iFrRTYjDn~+_Tuda?~_d{BYSo&!hS7uI=*d>4`_|xXE-o#h+|?
zh=dvwmIiy6`}hu3JvpZdv7VDSqxYMQ%DNQ2{Lj$3xhm5rFZ;oj*W+JAE6*y~PwA|E
wu>vDq^P1z$_jax+3s-luV@5gN#{2Q9h_9q2!pxq`A0;V+owXye&dMv{e<~b-F#rGn

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftbgn2c16.png b/extern/libpng/contrib/pngsuite/iftbgn2c16.png
new file mode 100644
index 0000000000000000000000000000000000000000..64a9cdf2f7fb4015cfededee285d015f96330cc7
GIT binary patch
literal 2624
zcmW;Odpy&79{}+0hMu{k(M};WMJ>4<_rok=GIGCPva%4Wg9urf`~5cIkuc<zP$W+&
zCC6D(%#mv@r?Z^7-{lsb@4R2H{eJ&!-+g|c%RWoAvbb<iKtccjaFAqTWCQP5?hB2C
z*Cz?T{ta&jf@~~o_x2UOF;fMAe~n~hVCU4<=hXT8VaKEA)TAx(=^L4YT|CUh!_2NW
z8Gf1At2`$526on^j})ph<R$p4o|YynIbH3Dpbb8~Vy!QK$lhK)#^@ho#KV6tiR!+n
zn$w}Mz46lN%)-qhxu_-?U*z2Sny#Rq`oJsBx-KWAOD{x)XpJF8?zy(@4S?Nj-uK`9
zwI%QUm>p{H?yeuYu9?5XL7|Vg@G%1<nPJ?M)U>#crW%*_;D~afi81aAE1Og)sZ&`U
zR~u4OQc?!zPC~{MKR>^j_;9AM3s04ue732g5?6`X_RhVx<Cf@6Dxt0yUW(k`wzRa=
z+Q`{<TrCCy;G;pX2A~b4ToEhp`JbDTqiyfx<YZ-^4uL=z8<`D!=?0G~v)Q@9`=W^}
zH-`&7`FUTUGlpng>P#k+2WGT1H8r0PTj4MzK71Itd_F#GHc|+i?<t;RUIrgaG5_w`
zbYFGgZ~33S&IqW0TtN(N+LtcdQBxy$RLRX>J1#yxK760<zUs$ZKZp!?q(JP%zF024
zqHfO0=En&bTY06E!V$`U+uPfTIhSA*-eS*iNkTjVAh3r8fIc07XJVIuWIQ6S-D3?Z
zxuzl})P4fyHtjS$F{Xo8fQCbY4JsRw?<+Qp7q05_ZFEVk?-}Dt`w$e&B`$Ozx^+<)
zX~H~ooIu@JEXJauuy(b>*KMJinq;%&<T6nl&=wY>VV??h8kfey_bGIGH4M!LDJd%}
zYiaNyBSGiKBn3yuXrvX6@dODL@t47pHV*Xmip5<Snk_TSRmzk#?_HfYS;2R&P~pRn
z$>Z(GN0r@QCyebCC#>Ch<6d`~M3*HcmEe;0i^88tDjWX#_3JNklEU#}h2=gvl7ztT
zA2LHnU{7KAm`hrEilPBJ1r`swV6wWp8XFrma?hesyr2FJ(kbYlf^|Jp1dmK%e)ei`
z&e`7D+ESOu@f<S6!*3|r*jk$zs3XHvQwih!TrVnO{#gpeOTP_Z|CxGBE8{w<<Z%)f
zmn3_}6oy4-8Mk{pb5f9g<T^W$F>Z7s(?nJ^@8YSfGxlQd`&ld&?T@Vrp=*sUH4bM<
zfF88{Vu-qZ8_VcBfQ*h#Qq|Vh%&|yM6;D;ap<XfvYpaxNn0?ENksWE+jZ%tA^GJV<
zH8qjSW{n$wKHatq*|rVpk>u_QTw|lar><9S4GoHlYHEs#hK7W37Mh;db4^_$^#fws
z(WGiyhIR!ed2&yZ8Bq1*=g*(i@MhRT!MA<YCCp{HF}E^c*}WPn6G9eN(xNYxaz7k*
z1|xPV_i&8lAsQPrG+1zEXP4OS3rp<mB||Bm%&L6`70MsG=S@y-%DnVa%}Y@@7q<Mp
z<0x6yw&Rh5puoHCbDY562w7p9%M)e=!pwlzZpJ&_TEihJqS|R}ZHwMbyg3gF3G`L@
z(L()we9@T+t>{E7ZWFIhh*&6exw|k{psNth5$>+;!;@XPzJB3~u}Qyeyo`!HUu>1Y
z32U+PZyuemduvfn?>KouAK~QO8X#Fz#8eS-Z~#2GBiy;={|E49n8k_k#vwj%5a8b4
zUGKiR`APp~kw|8`c{ww^;$FQ=MR|F-Kh<}-zs6>&U-5a;EA5Z`Hn(5{RrFp9rcfyC
z)hWfBeu4&MSKBJP$3^!ZS65f(=fT{DZPGoRG;<qVYWh7y3Jz?apt=3^9Lrj@SV%Jh
zR+{dwula>9ok!cr8=#3K(e?rnnSuih9H|87nJY8I@HRm6*4*~=^qg4fMgUcD_=B@G
z-`om?zJ{R>+^q0<@ZxJegh-Rpz5V269(VqJ5JAB$j2sHX$LK`>-e>@Na5NnK5zfLg
z>-%aDoY7b$P2prLPi0?HiNgXB%q_qfDx#hs*(8=5AU3|m!<KePqlm>7S8hV-grs(l
zrMeaunB`*<(_C|-)#9_H%cprh&^wyW(>-aN?%pX*_t|2{-4m>Oh0gkvLTlIip3Vmr
zw|91JE39Vuqp%}4YaFWEpXNcf6|lFSl<|Sfx3WB)f8>&1H8(d)rSYKkMTa}|t9XHa
zFTngFWP{Pi3%?6EBFMaPBiq!~6-+D(2T3|&B<o^!IbCdj6rX{9)~At&a5;E46kFl$
zn<kdv{$v9neF*5wm-S8sl??WBtw{3<#5VD+-T}>e=%-&prdxga7PsX(7REaapP}B>
zC%v!FW{HU3N5I~*OQ>uL!^0hNzq{H_-d;V4t=-bd2N*p7tgfxCudi!qstUEKd_tfY
z^VVdty*>F5mINwAh2pOMby-EC?MkW08|(Y$4G>mng!67`Xoh`ZIb1uj9_h5*ANlTe
z14jikAi7bnE@h-63jjeuLntD6YG}pOr%6kFaLzaQS>-7}ai&qF+m^#}&x!@TyghtY
zq9r4Sd*n$3Cfq266DEC->RxAB_TJMOPNk__6gHu_ShA?|pfD2r;ejFgh$bFBZShb{
zEYuR2t4wa8ZZ5CQXlM-79hY*tq<80e#f6;kJHx{#GGA!YQ;bYR8MX6@2qJ>vLoA*$
zMP?tgqsyMjLI6}eEFFvGrCL*4TPv*_r#d<~IJmL19<ng@W_u#HZQlY397H+RQhy9(
zpVj*P-qzITd<8RWg=988hHc@kG8u$qbp6!i(N^lzC8j(H`~q9c*_8(*7$>)Th%oh}
z(<@3#?Ub^Y!#ZV>CzjY3(xvqtJj92?-JgCg?(Seqiz!2JtkG|v_EIxk9oIEoL)NPu
zM@My8<6in>p4p<@aSPv-WcuSJ>@gGO?YzhWse*!H)+(emz6y)BFuFFL1yt3)xxKl=
z-L@1;TN{O<d5k&a0>bkVQ5l|5gJ$R9GRx@f8yFba+n@voYaBy8B;4J4ZlR^7rnWNI
zqzI*^ZZo52-xb+grR#*ukG#CadDumc2-Z1$YGgi<zp(pi=-4-gPkgD{pJN%rFYRTJ
zl?EqGPg@q^!&WE1bIH<Y3^K90i{9CzamLTL*B8d$MjSVPkRbcOmnTvmi%#IK3ZYF2
zDK5Q;-JhE)oSq26AKT;lKzx`p)mvd%L<nvkz1ei^lJjfWPBX+N#USx>xBmT<r{+x<
zVUJ&A{AKm!I6ido@7CzPeTn-bp|{gBdjiN0thIC8{X>H3f9AByue^ti+)LZ}&)tId
WtY3e({0;sk1SFz`QSJH5QU3=T4Dpo!

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftbgn3p08.png b/extern/libpng/contrib/pngsuite/iftbgn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..47d6eeb3c0f2f0133d6a3e248e9d6103398177da
GIT binary patch
literal 1507
zcmW;KX*d)J7{Kv&W-uA7DMyEPqok;zaV*hTJcA)2!_1D@MNA?`%;6jn!<c2<_mw6|
zB2zl79=94%TW&3t7Ex%CY<TR{hxd6uydT~Vzdz5}(N+Po2Lk{Kb|j*UWUGIhZ72YQ
z!PO>b0OV_D2UqK@t*v+O-igKHrKP2rnVH7M2OJK^&(F`7LgQ*_Ra;rL#KwLYA75Bl
zXlZHT@p$LXoeTH$j4(IntEi*{Bm!IlC;+&sqcb)zu(7ex+1Z(!n;RAu77`ek4NwLU
zp{N*w!<|N>vt(qV==6$;is#RtudS^W6&0~qtnl#gYXBmEUVw)H!NI}B#l^k7y>W4I
zOeQne(D1(Gs;DS%a%xalp8)s(5D*YBKK>>tDJdl-B{4BEIy(9ig%ZJJvf1qTz`%YC
zX6}a{LPJA6JUm=nT;}HH;^X6!Qj*fs(<37zeSCb}+}xa<ogEw;I0+ohd`%F7S*aO6
zm!F-TEf5HzqN1o&Dv3m*(P*iusc;9N8(<miTkW&5vhwrub8>Q$lapg&Vh$gUk&?>C
zVxzUSDK<8wgoFgyTe9#7U<H(>lrl3j3kwVRe12?fESc<u#Wn$m0WtyntE;Q!ugJqR
zuqs)^N+Rh7NpM|IR#sM0QsVCJPNmZ1<p%*i0hA+=o@lfMfRCCQt$(Orqd)_00z3g|
z2DkybIl85#rRC-2y1Lf^ws!B<QBvBA!BC8iDNqSe2k`GV8<PSP27}?~7>GoEMxlaC
zO)XVbExWtB4U-I^0U!<F8Jx^J36Fu0O#l#TXwWPzPnDEhv5K(zruz`EnOMjNS=j|V
z-s?MQGzQ}Z$p9k&lFuCgc~DSL;O*^ABu0E^3|w7Zwe`2fv2oA_&;^hMl2~v!S0vIG
zfd~O84hRhZK0piP<>l?zQHRIlm6d}e)I6RbEiDahgCX6J$RolZK+GgkC=`IwuV24<
z`+Af4WRNt$0}7Aw@#9A>m+Kki3E)d6ljr9bot&H&7Z*>TKE1iQnURs9v~@ueCm<Lu
zj%2Wy9-&LR7ugXlT}_^z^#WA5?oJu5aQcD_clZT%yG-;>V?A!J932YvCK99~q^%EH
zFgOhwXDr+lP#sfagTpl;mahA}Eu=TvE3+(mhF-LHjf+uFbR2NFo7FP<lw`H;pjxDU
zd)*U{mWyh_wT05<LTnJLmP9|M-%+@yXsiU&6lGfCvtP#jrF#5dpGat1^^{eCY&uGN
zw!GkPlgJwP4=X)|cdl6=&#cZX5*QDr-ZxA=j&9?gpoz^F?eSZmAJHC#US4+`Rf`F=
zWSSj7AzBmL-zi~tY*(7eOXxW-Tl4<?tlW{*aDTO>gyw(V_|ATuoSW8tJ2@#vD{qtK
zr-VtFjcXlN6&}1+arl<7v!L%<v&a;!>1=T2nBU8s^DizMG|~GIvbDc9(&w8#lNG8$
zMg|`4)_g;#Uu|vsTx3gMSvbx?UI-ZxZ&HV=x)~RmBKJ;aR9*k?RhhMn`2<r=wW@wX
z^8_E`F?N<8y564QQm^LZ9J4$o*LVNWHfc1awY{hNS(~`4@3MB+QQUzehdQ<E)%B{X
zg|)RuYbtB1>JZsR`a}A7{NS*WfpO#QyCTuOdoTNUW*Z=oYNu`^L(uzv|Alil&b2}X
zyGywjiQjLof!986t!0EGpfJ7!gFB+|u;mJta8PSNWysdX(C}xY`)duOckeZ_87$_P
zl~qfX+m3~1^}!rsN2j#hnWF2s)HBV(v$LX+spFz!RQq6BBlFe9{9B&cP~aX%75`VG
z4Gikg0wJ2(s!S>^iFrRTYjDn~+_Tuda?~_d{BYSo&!hS7uI=*d>4`_|xXE-o#h+|?
zh=dvwmIiy6`}hu3JvpZdv7VDSqxYMQ%DNQ2{Lj$3xhm5rFZ;oj*W+JAE6*y~PwA|E
wu>vDq^P1z$_jax+3s-luV@5gN#{2Q9h_9q2!pxq`A0;V+owXye&dMv{e<~b-F#rGn

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftbrn2c08.png b/extern/libpng/contrib/pngsuite/iftbrn2c08.png
new file mode 100644
index 0000000000000000000000000000000000000000..08ebbae2c8cc7ba70c0104a0abefd746475fe44b
GIT binary patch
literal 1624
zcmV-e2B-OnP)<h;3K|Lk000e1NJLTq001BW001Be0ssI2{21+{00006bW%=J0RI60
z0RJ~w8+`x(1`SC>K~zY`wU*CM8)q8Fzcb^pJwL!dFa}aXFkpy@smTvEg-cUu)kIxI
zi<0J;s?v%@s<i1XJ@k-6j{Of%FTM28AJQhNRx4IfrGPgIso6LLHUtNgH56>ezdbXa
z@yxt?m?R{-rjSbgYAz$q`~5u6^FHr84@C&UZz=jWb$>I!=H}+Y!a}7|c_V;r-!C$m
zOgtXHd-v}4_BNN#yOYTy?d`#H=LXK5^Y!)ZyPVo<4~oTNB9T~FSXf_Qx5=_AnRKtN
zGKE4Nr~oa1pQ4<RNcZGq&xH$zBN2vS4g{!Hs}CMLNF)+Zo;)#B)w#Ore*CyKo#qLt
z07al8ip5~C^7N@usc=99XtCROKK^)cVj>!ihQncp!_fp#uh*BBmhRubpG+nV!{D-6
zA(0SQR|QoS00+<o*nupNp{Q(Ur|R)&nGBuJw*xAWyl{be>n)aL8HNdkLg8?DczD?3
z@$3TP@%YV~Hx)&(UW2o<eTjq)(10R}+i$;Z`u#&oOWmoIXqqiR9jF2lkOSr@s`AMv
zcAkG3wIoTSqoY$(Q@fk&cDwC%JI8Ult}BXC428(%ro{7`$B*X*2MJ9B*cuw*Yqjvo
zN+gx?mr5>Om+khP-*1kNIz`d)QC0QXvuCm__xJa|R-#-kH#0M17>3PZ<Lq3c(U4_X
z)3k%PqhT2Ne7;;R>$<M%`pnEsS6A0=2Cc2F4K%*?f1PSgjghhQrSm@Cr|WvHR;$<R
zdzo6n5kku4az39|RaMt@!!X=#x8=SIa5x--T}TF!q>bE(-07X~9Z!zi?RKBfXBbAc
zT9qWJNefbxBuSY}ad9z}OopA#tw3O-r>7DQhnpNUr_(9ag_=?WjXOhk-dTIc3Xo-4
zpU>y@dMlMmtyX&(wWevgT&`R;fBf;ILZKD-XRTI#^vFfi#_;g)OWWP6f~IL+=Ai%u
zY;<gFdA0~4GUV^s@4pqll~}2*t*yJe+wFD($mjFvbXt<?vDjY<h2y|OnqH)+hk#bC
z+L{C0ZnvNakb$28Aa*212)WgMYqn>0mY)4e|B4X8FpSsh)pfm8DiJ~+KR&awa~xP<
zn16J1%nQOJQLOd!XrWN33Bc?1@(PbSumvdissAU1QPhTt7N7*K!I2lzG>s6VD6J14
zeh8Eq=9{sxTr@hs^8<$u<J76cHk+*pz~k|73I`Xk0c=CHt8@0bx>AP;5U_-O6#!su
z?fpiB2maRAmk|VRaq)NA?4MUw#)pTauQtMK0AAq%paA>~n7CKEXSrJsA;dIILWruW
zriu0S_kgm^7He&#=I7tbW_y7rqWG_)M+ch&yk0M-aL@rB+y;jnGJ(vFz5@dwpb2fc
zzv!PqMezW4{r*ZiT~yT^5C@7bmpU>svNxd4K?mFzNDW{M=)rnp9VVbbB%<YRnx?9%
znM?>!fOvbm%rM(Dy#qLb(PPIB34+iZz%WdwqZ19l1y8}_+w{Q&QYSD0^Lc$t)3nZN
zvFHJIfd9DNb+5O<^E_}GxIaGrzrUc@ewhPZ1FXhEgiOhijR<5w1Ps6gF`oleRV9Q-
z5)G^|jOldhHrsfuHU?xlF8}VkCw>WV`SRs2ykDGLJ~?8J^l$asx9sSEwFf-mEr8Xd
zjYb*RwAqY&zI}Q56yQ2^=&#>>_os=8iC+S+Ec@vnKmGC#Uy7VaH|U{_A=sX0K%2A$
zu<kxVSOK;*jgH5U=(-#T-1^~%Yae{@`~SbMnoJeZX!PpUtHEIK=+mPxo@ZdbkX53N
zj(aq{O$Z?*6%ME8<~}=iEQ)4oKDM;AwOzS#<^06?U?yl~U^8v6mdN9&b$0%}r6qOd
zjB9@W^WNS=*h71cEeyk4ym)cw-$T=}X{js?@`DCt0I)LfdcB&aoj!f?+O=ye%VKX)
z`;LyKQtA5j>*;iwVHldGQ>j!on<a!yPEKCBbcv?-8Qt~=03d|izI{6ui%}G{wzgI-
zm#3zt&YnHH@4|xuETvMZ8#it&FE39|PoFq(;()8(002Oi<wBtl2m}tk<jnxTLjMK6
WUtVfYto9oK0000<MNUMnLSTZmiXtBX

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftbwn0g16.png b/extern/libpng/contrib/pngsuite/iftbwn0g16.png
new file mode 100644
index 0000000000000000000000000000000000000000..4b7537e30508560b833f3d2da7dc8c620a34c301
GIT binary patch
literal 1448
zcmV;Z1y}lsP)<h;3K|Lk000e1NJLTq001BW001Bm00001afZqL00002bW%=J|NqFf
z-^Ty|1z|}<K~zY`rBi84lXo2c_3c{<MM_Z-iy}-^VDp+_P+(3ooWpA*%(!e*=bTg*
z6OGPu$=v3xb9gPzdd&lMMp*y_r!&MMLqK$*4I0bUmR3rkFKyqq$NN9_fr@}kKkWJR
zKc3(7yCswY006K6(`OFd6mbP8&51m5Vz`0@aIa|9*YT1r&aPc{`=b-`cUZl^_p3=Y
zTn0)rBZ4<m3Y1dX-oAKWTuWvKrIbo2{p$C4qe5XcnoN1w$4m@>Ea|c38asIKZwJ|`
ztSq3EQc4L~ytwn!<>xsV0D#@Qlf&bW>#hL+Nc8%XC(SDd?R|P&Ri-?glOv&YUqPVR
z<#ISKd}0PyJOgn1<N6MjO0N(2AYc&y0}!%DpXKw_9Dsi7@&P220xSz1wfVG*nQ<=}
zz#qr9ZN<fX#$hrkl}csz7Z$+dIdkU86WuDy4q3Khjx%XsT+<XbF@0NL;M}>XsS--P
z-c=u}_#yK-&g1E{qLkA5dY%snId_f)kjrU1K7cMta-MBZiI7UKUpEy$&S#JM)RsN|
z)O`n@{OE`>1@ZSq5g~hPZKCXL2dA9Rvi>wgad{hilnSj&rWScT2QTs(woLI$V<3Q^
z&<Wk`tz>+8bF;w^AHQ>FR~obzjK-e#m-^8gOwVg&<x7m`QY9rC&Ft%MX2xC}Yu!H!
zp>8g!sxDpPlByO-E-SQR5*y)Z^z9t8Rc(up&&mo5V*qa4P%81lL4(qBQ{z&<A2NK1
zA?AD($FjF>-M<eYp>)gY#wBA}T5PkuaLaLKv)5Zx1i%8Q-U!)9V`Oo|h5?w(lzP2&
zpO&8D|B4OrXVJeu{|}@SqKncUiHSkTV5s<3$dgEw20tM-mW{Ugo=ug1!^|MW<!UMw
z%96LpCVW1ji-2<thn{W6xo{q1r_-3E{G)QSFJOL|pAa4{7J7up@5ou{5{v}_O^mJy
z3Izxb?yBT_kCa^76|{lzAVi3Fhi43qyQuC~>dy}ED#z`3J;_CgQWW^`(B0&WBb|h9
z&04cPB&%Oxd3kelX{k)sN3-^Bn)XZ-0q)#+@!dlK06-8Fik{7U?L52=Y~Rl<E!EW(
z6&4Hsk!@XM#WeLa8fEXB*)0O6v!>?3gStB3Xp76L<SLmt=&opHr}U38i^99im5`*M
z=(L4NDdWZ^B*^7G1gfhG3*Bx?0iK+0iJ^Bv8&INd3^mvSJ2o;CSToTgHNN64uxG!&
zEU32AkmtvbU%J#U(AuiiVjOTsK3x<A!RLEb&KS3~b#x$vkXEZ!`)d#$9uUwlGguwj
zBG(43l}Z@~W2ckndz$jRRa<+{aFiVoo}pHy{jFAaE22U{qJ(UBghEU5BuPYXxgeW8
z<Y)O=LL3f`v)MQf&(kH_N4fX-R)`VKsc!wghdl;i_;5Om*ECj&g(MQoTZ_>2r&ntk
zLKr42Oc3mL&(R8-J>TVwTa~t9z{C-c=dMgh=p}$Nf^^283~suns#-`SX{1JCCIn+b
zoK7<Nfks5G^!Sl=j>;z2NXyiD^LmZqh!J?LI5RZUmTme|eavtQD^Zi|G{%Hr>~tD_
z@V2@hj9709b$=m-O82J@oHVJIfK)oV1RYVCz0K|v#=&%8CCSAagb?C+gj!~KF+~IU
z$X&AavPY8HU$1^q+OB0-v*y>v<!=ow$6L5|l?87gX>2k=2ss>-(mTEuGPI)N>6Zhn
zH*s52O3EvC0pq;9n|olDC4FSUV2)udmWBqawchNBo-CZ^!fIbJ%H6?n`T0hpRLU?7
z4OT0qnVAa~Fic;}S8iiNLqUN~r_m%P{x|1;uk*j3h8*&ox4E1E0000<MNUMnLSTaV
CsI&(F

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftbwn3p08.png b/extern/libpng/contrib/pngsuite/iftbwn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..47d6eeb3c0f2f0133d6a3e248e9d6103398177da
GIT binary patch
literal 1507
zcmW;KX*d)J7{Kv&W-uA7DMyEPqok;zaV*hTJcA)2!_1D@MNA?`%;6jn!<c2<_mw6|
zB2zl79=94%TW&3t7Ex%CY<TR{hxd6uydT~Vzdz5}(N+Po2Lk{Kb|j*UWUGIhZ72YQ
z!PO>b0OV_D2UqK@t*v+O-igKHrKP2rnVH7M2OJK^&(F`7LgQ*_Ra;rL#KwLYA75Bl
zXlZHT@p$LXoeTH$j4(IntEi*{Bm!IlC;+&sqcb)zu(7ex+1Z(!n;RAu77`ek4NwLU
zp{N*w!<|N>vt(qV==6$;is#RtudS^W6&0~qtnl#gYXBmEUVw)H!NI}B#l^k7y>W4I
zOeQne(D1(Gs;DS%a%xalp8)s(5D*YBKK>>tDJdl-B{4BEIy(9ig%ZJJvf1qTz`%YC
zX6}a{LPJA6JUm=nT;}HH;^X6!Qj*fs(<37zeSCb}+}xa<ogEw;I0+ohd`%F7S*aO6
zm!F-TEf5HzqN1o&Dv3m*(P*iusc;9N8(<miTkW&5vhwrub8>Q$lapg&Vh$gUk&?>C
zVxzUSDK<8wgoFgyTe9#7U<H(>lrl3j3kwVRe12?fESc<u#Wn$m0WtyntE;Q!ugJqR
zuqs)^N+Rh7NpM|IR#sM0QsVCJPNmZ1<p%*i0hA+=o@lfMfRCCQt$(Orqd)_00z3g|
z2DkybIl85#rRC-2y1Lf^ws!B<QBvBA!BC8iDNqSe2k`GV8<PSP27}?~7>GoEMxlaC
zO)XVbExWtB4U-I^0U!<F8Jx^J36Fu0O#l#TXwWPzPnDEhv5K(zruz`EnOMjNS=j|V
z-s?MQGzQ}Z$p9k&lFuCgc~DSL;O*^ABu0E^3|w7Zwe`2fv2oA_&;^hMl2~v!S0vIG
zfd~O84hRhZK0piP<>l?zQHRIlm6d}e)I6RbEiDahgCX6J$RolZK+GgkC=`IwuV24<
z`+Af4WRNt$0}7Aw@#9A>m+Kki3E)d6ljr9bot&H&7Z*>TKE1iQnURs9v~@ueCm<Lu
zj%2Wy9-&LR7ugXlT}_^z^#WA5?oJu5aQcD_clZT%yG-;>V?A!J932YvCK99~q^%EH
zFgOhwXDr+lP#sfagTpl;mahA}Eu=TvE3+(mhF-LHjf+uFbR2NFo7FP<lw`H;pjxDU
zd)*U{mWyh_wT05<LTnJLmP9|M-%+@yXsiU&6lGfCvtP#jrF#5dpGat1^^{eCY&uGN
zw!GkPlgJwP4=X)|cdl6=&#cZX5*QDr-ZxA=j&9?gpoz^F?eSZmAJHC#US4+`Rf`F=
zWSSj7AzBmL-zi~tY*(7eOXxW-Tl4<?tlW{*aDTO>gyw(V_|ATuoSW8tJ2@#vD{qtK
zr-VtFjcXlN6&}1+arl<7v!L%<v&a;!>1=T2nBU8s^DizMG|~GIvbDc9(&w8#lNG8$
zMg|`4)_g;#Uu|vsTx3gMSvbx?UI-ZxZ&HV=x)~RmBKJ;aR9*k?RhhMn`2<r=wW@wX
z^8_E`F?N<8y564QQm^LZ9J4$o*LVNWHfc1awY{hNS(~`4@3MB+QQUzehdQ<E)%B{X
zg|)RuYbtB1>JZsR`a}A7{NS*WfpO#QyCTuOdoTNUW*Z=oYNu`^L(uzv|Alil&b2}X
zyGywjiQjLof!986t!0EGpfJ7!gFB+|u;mJta8PSNWysdX(C}xY`)duOckeZ_87$_P
zl~qfX+m3~1^}!rsN2j#hnWF2s)HBV(v$LX+spFz!RQq6BBlFe9{9B&cP~aX%75`VG
z4Gikg0wJ2(s!S>^iFrRTYjDn~+_Tuda?~_d{BYSo&!hS7uI=*d>4`_|xXE-o#h+|?
zh=dvwmIiy6`}hu3JvpZdv7VDSqxYMQ%DNQ2{Lj$3xhm5rFZ;oj*W+JAE6*y~PwA|E
wu>vDq^P1z$_jax+3s-luV@5gN#{2Q9h_9q2!pxq`A0;V+owXye&dMv{e<~b-F#rGn

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftbyn3p08.png b/extern/libpng/contrib/pngsuite/iftbyn3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..47d6eeb3c0f2f0133d6a3e248e9d6103398177da
GIT binary patch
literal 1507
zcmW;KX*d)J7{Kv&W-uA7DMyEPqok;zaV*hTJcA)2!_1D@MNA?`%;6jn!<c2<_mw6|
zB2zl79=94%TW&3t7Ex%CY<TR{hxd6uydT~Vzdz5}(N+Po2Lk{Kb|j*UWUGIhZ72YQ
z!PO>b0OV_D2UqK@t*v+O-igKHrKP2rnVH7M2OJK^&(F`7LgQ*_Ra;rL#KwLYA75Bl
zXlZHT@p$LXoeTH$j4(IntEi*{Bm!IlC;+&sqcb)zu(7ex+1Z(!n;RAu77`ek4NwLU
zp{N*w!<|N>vt(qV==6$;is#RtudS^W6&0~qtnl#gYXBmEUVw)H!NI}B#l^k7y>W4I
zOeQne(D1(Gs;DS%a%xalp8)s(5D*YBKK>>tDJdl-B{4BEIy(9ig%ZJJvf1qTz`%YC
zX6}a{LPJA6JUm=nT;}HH;^X6!Qj*fs(<37zeSCb}+}xa<ogEw;I0+ohd`%F7S*aO6
zm!F-TEf5HzqN1o&Dv3m*(P*iusc;9N8(<miTkW&5vhwrub8>Q$lapg&Vh$gUk&?>C
zVxzUSDK<8wgoFgyTe9#7U<H(>lrl3j3kwVRe12?fESc<u#Wn$m0WtyntE;Q!ugJqR
zuqs)^N+Rh7NpM|IR#sM0QsVCJPNmZ1<p%*i0hA+=o@lfMfRCCQt$(Orqd)_00z3g|
z2DkybIl85#rRC-2y1Lf^ws!B<QBvBA!BC8iDNqSe2k`GV8<PSP27}?~7>GoEMxlaC
zO)XVbExWtB4U-I^0U!<F8Jx^J36Fu0O#l#TXwWPzPnDEhv5K(zruz`EnOMjNS=j|V
z-s?MQGzQ}Z$p9k&lFuCgc~DSL;O*^ABu0E^3|w7Zwe`2fv2oA_&;^hMl2~v!S0vIG
zfd~O84hRhZK0piP<>l?zQHRIlm6d}e)I6RbEiDahgCX6J$RolZK+GgkC=`IwuV24<
z`+Af4WRNt$0}7Aw@#9A>m+Kki3E)d6ljr9bot&H&7Z*>TKE1iQnURs9v~@ueCm<Lu
zj%2Wy9-&LR7ugXlT}_^z^#WA5?oJu5aQcD_clZT%yG-;>V?A!J932YvCK99~q^%EH
zFgOhwXDr+lP#sfagTpl;mahA}Eu=TvE3+(mhF-LHjf+uFbR2NFo7FP<lw`H;pjxDU
zd)*U{mWyh_wT05<LTnJLmP9|M-%+@yXsiU&6lGfCvtP#jrF#5dpGat1^^{eCY&uGN
zw!GkPlgJwP4=X)|cdl6=&#cZX5*QDr-ZxA=j&9?gpoz^F?eSZmAJHC#US4+`Rf`F=
zWSSj7AzBmL-zi~tY*(7eOXxW-Tl4<?tlW{*aDTO>gyw(V_|ATuoSW8tJ2@#vD{qtK
zr-VtFjcXlN6&}1+arl<7v!L%<v&a;!>1=T2nBU8s^DizMG|~GIvbDc9(&w8#lNG8$
zMg|`4)_g;#Uu|vsTx3gMSvbx?UI-ZxZ&HV=x)~RmBKJ;aR9*k?RhhMn`2<r=wW@wX
z^8_E`F?N<8y564QQm^LZ9J4$o*LVNWHfc1awY{hNS(~`4@3MB+QQUzehdQ<E)%B{X
zg|)RuYbtB1>JZsR`a}A7{NS*WfpO#QyCTuOdoTNUW*Z=oYNu`^L(uzv|Alil&b2}X
zyGywjiQjLof!986t!0EGpfJ7!gFB+|u;mJta8PSNWysdX(C}xY`)duOckeZ_87$_P
zl~qfX+m3~1^}!rsN2j#hnWF2s)HBV(v$LX+spFz!RQq6BBlFe9{9B&cP~aX%75`VG
z4Gikg0wJ2(s!S>^iFrRTYjDn~+_Tuda?~_d{BYSo&!hS7uI=*d>4`_|xXE-o#h+|?
zh=dvwmIiy6`}hu3JvpZdv7VDSqxYMQ%DNQ2{Lj$3xhm5rFZ;oj*W+JAE6*y~PwA|E
wu>vDq^P1z$_jax+3s-luV@5gN#{2Q9h_9q2!pxq`A0;V+owXye&dMv{e<~b-F#rGn

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftp0n0g08.png b/extern/libpng/contrib/pngsuite/iftp0n0g08.png
new file mode 100644
index 0000000000000000000000000000000000000000..aa826b8630866f46adc93a224c4599c5f522c896
GIT binary patch
literal 847
zcmV-V1F-ywP)<h;3K|Lk000e1NJLTq001BW001Be00001Ar=+B0009PNkl<ZILm#K
zO=whC7>3__?zx#vCX@MLrkIGaOj3!U#zn1QT%-u4MCvYdV-Q<6rHGW2(uFb$BhnU1
zL0q^BqAub}5K-zPnEvQ!kv7qokeO(1I(H_?{AFhDow@g(pDt!hQbfPi;e0Re`JVTD
zN*n;eA9|f)C^$w?PmU;Y0MuK2<{?RadN0{tD?o|k%;>|ueyD@1Mr?<B^%Q|NcW>KG
zb%r8@%U_NHN*s+MK-=AkVL(ZaXQB%se?Sd|chbO}sY3+6F9wq>8VLMJX9nMaVrRCl
zk~-8uw966Srq8L4pBo2?@2}0zX0*vlM5jkukKLzGo(6|XbpQwCqPe__;-cgX*+c5D
z|ISe-Ge!VszMM8)R(#P?4vc{SSE7cn?feY0BgbFAGCa0Ft@pJ8fI0{Ovk`XMpa8b;
zV3P{~F!aBR!R*tMH*ST`H9U?^=f*Qk>kv==^u$gkDDHRU-|JW0bPYT3AO;HlYTuq5
zXfI^Ru%|!~^h>Q9hO|?^nLPkO*o1ig{C%b;EF}OC^w3<^Lqv7SI;foh2zt1l<=~a&
zz+>lgfZ(!Q?-DAvShp8H0R%YGk!OSn+vYbLlO})QTrkO||4KARztrh%XJU78d=t+9
zv5QYHY^9w%v$sk6Mjm)eJ^=95N77h$sK>t8Drh*2PXCi~GHWHmTpBh^)!%yf!~WeD
zn}W}7*Cggwq@r~Oa%Dm}XHMZ0F936Y8WiZ(NQ)<8IRFsdu;%%7#?D@W5(j)QeO-#G
z5?(QzU2}DAiAFmQbASS96Q<=8ipXf&J)&I7mH2F-=2k1UUnUw9F=;Kig0HcK7lMSW
zqMayI`v$@v9Ghrj#<+J`mrpDq6v0JB{Oy{3smE1gxUsK5FGnD!ZCmbQ8Yi-%+tuE*
z1#RHo>!8l>VL`j5DqL{JOtxanNT;UZTWsv26C6powio57Pp+>TRgoz~ZU<7E0$|Sj
zqrE7qp*EQ>swM^|t@$Q#Qvgh@wVzcSDOalAudgp8HUira0C-dq$5X4{td}0V@mcSv
Z{{Y4hZLe_zAaMWy002ovPDHLkV1jkqg|q+w

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftp0n2c08.png b/extern/libpng/contrib/pngsuite/iftp0n2c08.png
new file mode 100644
index 0000000000000000000000000000000000000000..b12bd0a7fa90aa14e47e62bb4e9bd5bf9e1bab77
GIT binary patch
literal 2020
zcmV<A2OIc_P)<h;3K|Lk000e1NJLTq001BW001Be0ssI3iyz%J000N8Nkl<ZNXNBR
zYfMyU8h+-?nadf*;o6al%yLti)lo<kFQIl4HxVHcN_AH)wRO=L+f~;1Lz~sG7Fkx=
zvNVbtvr)6s#I@0AYV9KEB8ban5oAUxR7RA6ab{qc+d0hbT=oYjVo=*3`}{dM=X~$w
zdA{fUK2d3DDV~D>u=3=|Ma|8Azn=iG{)vPB=%aJzWTMj2QkhIf)3ih)5zUC9D9Z2m
zzklL{(P$(t@t2MzAIlhb=yW<FFOUZpfSmxQVoFL%4wsa~*VZQLbf&^W03?7f7k?R5
z8<nwUjX62__VDo8Bhi;G#S;LE+KS3z%658p#>U2;Ju3y0jYi{i`O?zT;^JbBMl<<3
zqpz1iPCgV0h3MF^;Q08K`}faZxdK3Z=FFL{uCB0q_r}((E9ve1o7L)-NaS+4I5IM_
z>_FN36Tc@(vN<E;)IT>iHs06kl>`8s#@Dj1BO)RO1_q*||1J_OoYD?+ao2G-7z{Qw
z6-lLr@^W(ON9m(dq`~j^M@60F`SpQ-1Aths*8|X7^@1RL{Bc2excyB$cI?=pQmLw{
zs%GbR@ZiDP+S>m9{+Nb_xduZNFm~ifqevvxYS|xtPyvH`_sZq+{QUfeh6WOVNF=J{
zDq}KZwkGWyak)%>|9_w76AB9Kf?#|6m|+;R*}P!E0un$)MFktjwx+cb1Q9+I{yq2o
z8TyP^EUvGwfB0}+clZ3bxNTl<rqg-;=+UE7<a{=t>6yvA+{{1VofFPnAs0YvE7{tr
zRjZHNY|GW^37UTRTtDF2pRO&#vf`>@liCCZfk43FaJ02)WwLL^#|z`*hl-1}v#V72
zo5G@h6nz-^;mF9y(9lqNdb(ULe|f=FOE2)S_o0^5vMjr2&mN1#LXzYwvcA?&uLCjb
z*WBFPpA?|i>#bI6sJ^~s#R~tCBMD!8q38L-hY!EXAulh_U@#D7^Tg+$FK%yNIXtWa
z=(xBssnl0jcfPlmS13|aQnqj3-rn9$0%&MxP^na+$B)%&b@%4YT?C<^=}p(KM|-_D
z)6<n{X#kp<no?3yo|BfKJh{BWSwV)#v9Yn28xRD+<#JgpmOvnom6bKcAzBs9#<Df*
zYa|khMx)VaG$cui#bTCa`}-}YPW|@k)wrimmD8l7qN3oyletfLp5K+a>y+qJQc@Dj
zvO_~dmoJ|ai~p)rUW$z5rvp+`Qy~K$qn@fq7*s(O&+{}*8w?wP3wk|G)5o`O&z~8<
zg8C2jo$@=dAb5h~IIq{++glhP|F2uO76YA|H-9i4P*YO_AC})+4jsTEj1S{DZen5r
z7@R+UT&eT`sI07<v2oSP>Qo_B`bdf(D2`%Tmgjk(kzpcf`d8Pl7reUD&TePrpDPQS
z3K0ZYuq-PG0zq_jcFG0^mvwZs%;MILj*b|4On?Zibgq<$C1$gE&Yb?i!OJI3RKLl5
z>xS2@eQ#|j6atWwlT%(^{&u%EHa3=&l<0K2S>5`x=i%pqc<YMYyLV@0WeI{{u~?i&
zqj2TQ!j_ht$jIMq+xAlmyvktz{{04np{J+EWHNDqfV{sy;>RCVX0t*NJb)AMD3#9S
zWY5#5oX0}}i-9>(sr8dj7OY;qbm>y9R$Ea~F-w6B8#Y|KcFpJW34#D1xxPN7r-uay
zz^7C`Te5^#s}~xLiGzbmo}UBw0WZJ+qre@J$n)u^QibA0QifqNGBQR+M)2Y)(`Ymj
ziG&~sQbtlz%DZ)IYe7LU7<{>xXIky+bWi{s$2lAhx7*FKEX%To4jnpu`t%Hm!otE1
zXb%X{0v2OS%a&CGtHfe4K}^jN!!Wa^W*Ek1b9Qyj9~e-{<s<XvJ<(`9+1V>Oj+<OC
zeab2nig(7}v5V|*;li2=iDQY0?nFP~zoEE+Xyo{EA`rpzyvO5lxm;soV=kAA<IvQ!
z-)c<-t`fv;hB5W^r7?`Cx_aZqix(%;PEU?br@K3RcT_ZrQ6K@G3p=xWv+E-3ZZ5oO
zdTMe9-I?M{f*>f0vREv3yWQtgefw>V#}h6V|8d2Ne=l0Zcs#zOBzb;*!lOrzX0d5X
zN=o#2G{S){;2r{GplYJZ&-lRsJS4n?=Xs9fc%Juqy*!T_H!4D*5J~<aBg5X^om*G;
zYrB2z(2#u7rcEzvI4x0HT3VDd3Vt9Sx<;LmGTK(#>|J(*fB;k?6~}P|K?s82^?DyX
z$n*K+K=q<UR*S_H3Q<4=kgnI$b#-;K4_aASS$0ykgpnWtGN(-6qK5<mDIf%};5mNM
z9t^{<EIT|L4crlnpTx$}YV|Une-HR2Mcq1ha7O!h<*p3|gYUZE{c6=$qlVG&vG9;T
zWdDU70$@cZG82#>2!h+~w%hGyvwvd32DnV7C01+Vym`I1Z|B9tjG9cQHx-yfUtb?Z
zQOA!TSC6PW?VT>l1v_+tE*7zZAUGTjr_)JMy)1hN5cK-+j*h*dP)~n<->g2KrNAVb
zo0~^RN0-t|uWr7owP@uoxgZFFAlPg+nx-j=`s}k^7cTt8WNK?~Z^P^H+5#`o*4E~7
zxp<y0Dk?IWOm@3{-@birx7+1%H8nNiZTP<**Z%{6(Z;bIFwlbl0000<MNUMnLSTYh
Cjq;WN

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftp0n3p08.png b/extern/libpng/contrib/pngsuite/iftp0n3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..37aa0cb0d92dc712c9a39789946fe4f18c355d8f
GIT binary patch
literal 1495
zcmW-gSyU1T6o#*;7=%f=v`=EIjo2Wdl@p~0lQwr@XmY_pDaj=T6mdnt$Xswi6HzmB
zDRast(&LO}E?K6TZPZYn(wtFK+tjff$9lNufA}B%hwr;GHy39^^cpk(7#^TeJr>ja
z+bz)r&>>!Eb^}1Xay#thl#r0{=FOY#?(PpCK8%cvG&bIdkB<)w3}n-p(k)x6935NZ
z;>NVviHV8U)>fHJ#^G=xeSD%Rlr&S*41g4XM1TT-3){CpfAr|<*RSpE?Rj~55fKq#
zTy73PF+jADQ5YWYZeWm&M8*UKm6n$F_4Uop&K4FH3Iu}4$jFNTbpSm8O#q>xp-QE)
zr>BR{=jV|~>cz^)DAU#Tnz{K)fH8pJ;9#wGP$H3>K7BeRB}F6>CDQ59e123^R1%jv
zfJTolTNWN3e(cyW4-b#g(b1%&B*|$>Mn;BEC=3V)@b>n0b8|a<_;9>9epCJ?C<l9$
zeOg{xPEJl{W@b!G41>X-(P&I2^URquP!G@v@DUE)JeZxGou8kdo12@Oni?A$yKP&n
zo?bo{E3&kt@83@oi^ZrbDEI^56BrL0%jNQO=gy_2rNza?d3yR|vCRP80CIriRaI4(
z^B8ywf-(WMj7qDfWmaYu7Z(>56&*c#l)+$PFpmMI07?)D9|MDZ00C>)G6$Xv;0kbX
z8Q=~;3qUnk=US^&s*;itYwJpYh1ILK8yl}fqv>{bbSML;1$h4r%+7+HJRZ-*g^NIZ
z*3}K!z1zXe%%QWhlO!R*HGp)0UO1#U1YNKvXAeL*4##wGI8sz}-Z9$o8`>to%CV3S
zDAWXj;QyVc2#xlKRDfpyi_5nG6i`r5z+$ne)adUFxzp3r&c~hcQFyoo&;gJQi>Bc5
zUI+wRM<)zG85|xAX#lODP$*Wcs3i~xCMF?^sAaOu^z?MN3Zx(sRYrxgK$TPJbUJ`)
zZf=gnW_hN0!lDy0pv&mv<Kt4P)F;FTfbHq&`R?7MtE=ne<fOa1`~3X;!oosURu*Mf
zK4MYz`U6x4ubuaP^9Nm`H3uneudqT&8SdESNP7;$RciXNQukcnt3<tMeW%U)c)oI+
zG9i$xd;4OcH{)`s*ffFClZc*`IBibKO;2vBS6;Bs^3L+`IO?m<u0a#eYTZ!m6kkP?
zVBU=OUiD(c#{Bt7ro6|WEhUmkjk`>FpLshwsF;Rw2Lz6_e0teF?C{F<CQCgY+Tp5M
z4^0{sCrpV!2a@z`C$%dhrrbWtFWk%coM<R)5ywpoTl~ir*@y;_GsO+W=*hFAg8fKD
zB1+P=)qIo1mR`Jm-oOg4{{DfLbd!+>wnO^D?w9>--I|WaN7^)+WTS1^b!&e32L#Q0
ze+=zVL_90_6hT)R$#n9zrIj|fnhReKRl8psu;=t5QC5CUG54SIJuwwmUOl^p+B8U3
z2Q4J=3sWm+#wmhzC&T`h#W9|gQ`KQDr!cRxI=2dcE!nU4^K+rGS;Y>&uD$7)Umk`e
zhkp?duIL-fbdUXb*Z97=3#D&Bzu9)Tv-eha$Ngl>4lDe|AGfw!{%*dbqN=>6#_Cep
zrHWde9CE+|8(Z7{r(`mbpuXDBP*?Y8U}X*wiQpc&ir66v+u#?E-0M|3yaBta9YL_L
zrr-#c%q^SA`1NS^9vhqby2yz0g7PQrPt6`Vr98DG*^<B1G1U#%8>4sv{>&#w)2lAU
zM76*-dOqdfrG?50>$5%$H{!Y<76fYQeqtO9^=%3qYYAbYUOYXq#%1|&ZU3Ka&f8k8
zNO9YQrYhh~4OI_tTvW^)j~b0l$a_sBvDfd$jU~%5>XE;iL}6{yvY8FkJ5-9*-WUpJ
zWX`!>u`xBbS?9~pET_+pY9=&btM(*Z{~+BR<A2b5MyvT!HZ<L)KE&az7p9V}DOH-*
oI^)?@Rnw@bSWPU;&Vq18$B;HP98``|F8&T2aB`v6I{J(M2VkRf6#xJL

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/iftp1n3p08.png b/extern/libpng/contrib/pngsuite/iftp1n3p08.png
new file mode 100644
index 0000000000000000000000000000000000000000..47d6eeb3c0f2f0133d6a3e248e9d6103398177da
GIT binary patch
literal 1507
zcmW;KX*d)J7{Kv&W-uA7DMyEPqok;zaV*hTJcA)2!_1D@MNA?`%;6jn!<c2<_mw6|
zB2zl79=94%TW&3t7Ex%CY<TR{hxd6uydT~Vzdz5}(N+Po2Lk{Kb|j*UWUGIhZ72YQ
z!PO>b0OV_D2UqK@t*v+O-igKHrKP2rnVH7M2OJK^&(F`7LgQ*_Ra;rL#KwLYA75Bl
zXlZHT@p$LXoeTH$j4(IntEi*{Bm!IlC;+&sqcb)zu(7ex+1Z(!n;RAu77`ek4NwLU
zp{N*w!<|N>vt(qV==6$;is#RtudS^W6&0~qtnl#gYXBmEUVw)H!NI}B#l^k7y>W4I
zOeQne(D1(Gs;DS%a%xalp8)s(5D*YBKK>>tDJdl-B{4BEIy(9ig%ZJJvf1qTz`%YC
zX6}a{LPJA6JUm=nT;}HH;^X6!Qj*fs(<37zeSCb}+}xa<ogEw;I0+ohd`%F7S*aO6
zm!F-TEf5HzqN1o&Dv3m*(P*iusc;9N8(<miTkW&5vhwrub8>Q$lapg&Vh$gUk&?>C
zVxzUSDK<8wgoFgyTe9#7U<H(>lrl3j3kwVRe12?fESc<u#Wn$m0WtyntE;Q!ugJqR
zuqs)^N+Rh7NpM|IR#sM0QsVCJPNmZ1<p%*i0hA+=o@lfMfRCCQt$(Orqd)_00z3g|
z2DkybIl85#rRC-2y1Lf^ws!B<QBvBA!BC8iDNqSe2k`GV8<PSP27}?~7>GoEMxlaC
zO)XVbExWtB4U-I^0U!<F8Jx^J36Fu0O#l#TXwWPzPnDEhv5K(zruz`EnOMjNS=j|V
z-s?MQGzQ}Z$p9k&lFuCgc~DSL;O*^ABu0E^3|w7Zwe`2fv2oA_&;^hMl2~v!S0vIG
zfd~O84hRhZK0piP<>l?zQHRIlm6d}e)I6RbEiDahgCX6J$RolZK+GgkC=`IwuV24<
z`+Af4WRNt$0}7Aw@#9A>m+Kki3E)d6ljr9bot&H&7Z*>TKE1iQnURs9v~@ueCm<Lu
zj%2Wy9-&LR7ugXlT}_^z^#WA5?oJu5aQcD_clZT%yG-;>V?A!J932YvCK99~q^%EH
zFgOhwXDr+lP#sfagTpl;mahA}Eu=TvE3+(mhF-LHjf+uFbR2NFo7FP<lw`H;pjxDU
zd)*U{mWyh_wT05<LTnJLmP9|M-%+@yXsiU&6lGfCvtP#jrF#5dpGat1^^{eCY&uGN
zw!GkPlgJwP4=X)|cdl6=&#cZX5*QDr-ZxA=j&9?gpoz^F?eSZmAJHC#US4+`Rf`F=
zWSSj7AzBmL-zi~tY*(7eOXxW-Tl4<?tlW{*aDTO>gyw(V_|ATuoSW8tJ2@#vD{qtK
zr-VtFjcXlN6&}1+arl<7v!L%<v&a;!>1=T2nBU8s^DizMG|~GIvbDc9(&w8#lNG8$
zMg|`4)_g;#Uu|vsTx3gMSvbx?UI-ZxZ&HV=x)~RmBKJ;aR9*k?RhhMn`2<r=wW@wX
z^8_E`F?N<8y564QQm^LZ9J4$o*LVNWHfc1awY{hNS(~`4@3MB+QQUzehdQ<E)%B{X
zg|)RuYbtB1>JZsR`a}A7{NS*WfpO#QyCTuOdoTNUW*Z=oYNu`^L(uzv|Alil&b2}X
zyGywjiQjLof!986t!0EGpfJ7!gFB+|u;mJta8PSNWysdX(C}xY`)duOckeZ_87$_P
zl~qfX+m3~1^}!rsN2j#hnWF2s)HBV(v$LX+spFz!RQq6BBlFe9{9B&cP~aX%75`VG
z4Gikg0wJ2(s!S>^iFrRTYjDn~+_Tuda?~_d{BYSo&!hS7uI=*d>4`_|xXE-o#h+|?
zh=dvwmIiy6`}hu3JvpZdv7VDSqxYMQ%DNQ2{Lj$3xhm5rFZ;oj*W+JAE6*y~PwA|E
wu>vDq^P1z$_jax+3s-luV@5gN#{2Q9h_9q2!pxq`A0;V+owXye&dMv{e<~b-F#rGn

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/interlaced/README b/extern/libpng/contrib/pngsuite/interlaced/README
new file mode 100644
index 0000000000..f171eee01a
--- /dev/null
+++ b/extern/libpng/contrib/pngsuite/interlaced/README
@@ -0,0 +1,2 @@
+
+These images fail the "pngimage-quick" and "pngimage-full" tests.
diff --git a/extern/libpng/contrib/pngsuite/interlaced/ibasn0g01.png b/extern/libpng/contrib/pngsuite/interlaced/ibasn0g01.png
new file mode 100644
index 0000000000000000000000000000000000000000..828fa76036960205f96b4cde8e832c9bd9fbd7ea
GIT binary patch
literal 201
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk~Bp7wr%FhGo37#&FAsp9rdky&x8SuE?Kh|_a
zRHBMuiJoND4!P!y>JNCrEE$B8mp0sp&`CWhU|Qo{v0?xI`~C%DJ(ADY>?~OP>EgYc
znK4iIM<(CDskPo`{!R5)F7r~_??=xudp>ig^nDI(U+*i7{!bXa8CO?{uX{G-Qm;{$
zZgO)~fvcRDM}h9F`Ck^w>Q@D>Qhd6wr~WU)l*fUxy@fG7K({e?y85}Sb4q9e037{I
Aod5s;

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/interlaced/ibasn0g02.png b/extern/libpng/contrib/pngsuite/interlaced/ibasn0g02.png
new file mode 100644
index 0000000000000000000000000000000000000000..7fc17e3a1eec51c568cba7c9c47e82e15cfbd62f
GIT binary patch
literal 138
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk`Bp9=o@yY|~Ku;IP5Q)pl0ZA_s7#<e2?M|38
z`EbD-i78X2u^F1>xukDimmYgw;H%;*X66Y8PcfvpJQQ>GP)HH<@(4OEu<Mn*#9>JZ
lCLRMv7UpGK2Nz7TWSA4w;QQgGRV&bN22WQ%mvv4FO#qqgE8GA8

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/interlaced/ibasn0g04.png b/extern/libpng/contrib/pngsuite/interlaced/ibasn0g04.png
new file mode 100644
index 0000000000000000000000000000000000000000..1beade28f57f1c708311fd7692f5276a8c6d15f5
GIT binary patch
literal 231
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk^Bp9DO`>`KLuk&<q4AD5B+7~Ez$UwkFTt);4
zS!7zQG)e_tDO_<p;CK)S4>(Q~Pzhn4={e)v*}6M#-tL}#`|zei+gwXse;?U(aG!Ir
z`}bp6<u=OKcsIs%d_9^}Y_ZfaM=w)qwtH0PS@pLIHKwlX{kz)vnp`A%%GVQCO4$zA
zGWQ*3|7ql2Al6=Fwcqf6^CAuJrCZizC$C9WSX<1q<ZU(EB|c{6%)RLfZ!L@_n6a>3
d@)K^9S8sg1(s1{YexS=4JYD@<);T3K0RXM9TwMSF

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/interlaced/ibasn3p01.png b/extern/libpng/contrib/pngsuite/interlaced/ibasn3p01.png
new file mode 100644
index 0000000000000000000000000000000000000000..f91e7233e70e8ddd23359a3e14e00a46ef7f3f1a
GIT binary patch
literal 116
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnL%)r2CxA}%5ki!<>6XN>rzmihg{~W1HYCsW9
zPZ!4!j_b(@4Nd$3JGi)<FK*aqczCAq4Ns0{4>NlKhYo%R21N}4W(Lk(PP#Jt;%5Oh
OF?hQAxvX<aXaWF5${vmY

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/interlaced/ibasn3p02.png b/extern/libpng/contrib/pngsuite/interlaced/ibasn3p02.png
new file mode 100644
index 0000000000000000000000000000000000000000..0f9ce76e6b38677f0524a9aebfa5fcb1eed0c496
GIT binary patch
literal 163
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnH%)r1{DZJ<-ki!$;6XMFi@c%y)Gbp6i{sxK%
zdAc};NL)@1NP3aL@UW<DcS6k@31>gPDO0Ag8Jgv}q;FoA9((?S;wxtn<_QN+F{IQS
z&~2OGa6)Oyge857C0FYW+Km4>M{=-*D2W_AaKS~lm|?}Q2H&!nhvq=j89ZJ6T-G@y
GGywpYt2f#J

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/interlaced/ibasn3p04.png b/extern/libpng/contrib/pngsuite/interlaced/ibasn3p04.png
new file mode 100644
index 0000000000000000000000000000000000000000..b2ca720747a6db3c08049b82ae44285fd7f8b075
GIT binary patch
literal 288
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnF%)r3-EjT<7$k7e(332_;!0<nf;s0)iyZ;%=
z|1&6o_%00pXEOZ%&oJ{pgUf#<hW{N5|L=nMyWc%=VghPh=jq}YqH#X8FHrE1fq;v+
zj0h02$h25#lnT63xZ-%g@gNW$aGWTh62d&wbH=%|b$8yp-97vE;Z29Oxt6;AKC<iJ
zKIdZh@5i#rZIrL^Zj9^rdNirnVyR<}UZ&J+_o&XZ>TefnOkLOeceV31xk&buuP3aO
zvK_8v?mNu>)5yI*ti8x;zv2JpMH=2qx2(%fUX!Y@wwPzh+iJE;e9X+5d(#!(S{O|*
gV`01GC)_Bn-uQZ@;qD{-K$kOky85}Sb4q9e08!+0%K!iX

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/interlaced/iftbbn0g01.png b/extern/libpng/contrib/pngsuite/interlaced/iftbbn0g01.png
new file mode 100644
index 0000000000000000000000000000000000000000..6eb27d10e8d587875d1abf309b32591d573b7ea0
GIT binary patch
literal 214
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk~Bp7wr%FhF7rjj7PU<QV=$!9Hqynas?#}JO|
zu|3vYha5y)`31KMZuvG{cSlQO!`7{NNh-aq30me4<5G5&OiScCDdfW0(aLkrbK!%h
zg>vHOsv8mycFdT%?VwTS?8OI)lN`3ceUp%TVw%dl6lUjrI}dZ;WI290Fis=;*St8<
zcEdA2&o2}xQqNf*wpHxg%7n}A0<)ygNO@lVqqDNOhvVa?ztx`@lQdM8DRV!O1Uiku
M)78&qol`;+0Qf*sZU6uP

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/interlaced/iftbbn0g02.png b/extern/libpng/contrib/pngsuite/interlaced/iftbbn0g02.png
new file mode 100644
index 0000000000000000000000000000000000000000..46ba4977792db7242ca14bd6b484424bd133284e
GIT binary patch
literal 211
zcmeAS@N?(olHy`uVBq!ia0vp^3Lwk`Bp9=o@yY{frjj7PU<QV=$!9HqydF;%#}J9j
zwZ4vgEQ%c27QPj&A5$up-n@JyT)@92oNq<(P2X+pQA>0gxFlL!dbcw$T{zIjBs)WP
z{>HX0@k_>q?fVNd4~VM8l(NdkN663XEIFvVY7gtm6|BD9hhnzg<ZFDVa@hXFE1!c^
zEWT6s&f3;GDW9=OeY@_BO|zDLUZo%^_gvz8S<C+CvGx7-6Q1abKYkLz4RjZSr>mdK
II;Vst00?1CAOHXW

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/pngsuite/interlaced/iftbbn0g04.png b/extern/libpng/contrib/pngsuite/interlaced/iftbbn0g04.png
new file mode 100644
index 0000000000000000000000000000000000000000..e9db0ad50d0b43fece4191d0cee877d179727461
GIT binary patch
literal 489
zcmV<F0T%v=P)<h;3K|Lk000e1NJLTq001BW001Ba00001<mULl00002bW%=J01xIY
z(5V0b0isDnK~yNuRgldu13?(Z-#@{&y%01*I7y^-ai-KwQvFyxH6b(GCK8FHJKa+g
z(srGM=*J|)&7Xjq8*%E9o13`xLM^JV*|ntRF!{aD`_4Si3?Rab0nQOPC6HWQ209I|
zVZf&egpM$WphFL3iQ6bQIe~jq2=_+11Wt1&46jxq44sU60GLx{*SYrQzS`bwBdTfR
zMhnnra?X=k33k4=KxB(nGRJ{{gbvH>D%0+%?m8{ukIf_cfIf76xL6xMlh8HQXmr+U
zgHu`IDZOwFPOi$inM8OmiUyAd5k7MDe1U}Iu)(d(&>%vO8rB9Gb=|oYUkFP$XI4Do
zX6~_Ke8jVOD<*u?tE>+_?9bDmOZF~l?DS9Q-I+;sMk8Z$C!TQ23#yh*E-ghTInPVs
z*|xdA%+#v;V}>n6)vXhXb|8g!X74vFQKbno5O|crC(GG9EgGq@;NrY{=@*NYxi0E!
zB%%y^wk*YUUDRfRM9F$Wg&JvHlu0O}w0@G_FsAR9i4ti2M*m>CU04jY``*&DX{P^i
fh!0!%U-(<!+sjtKJt<uL00000NkvXXu0mjfWXs>c

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/powerpc-vsx/README b/extern/libpng/contrib/powerpc-vsx/README
new file mode 100644
index 0000000000..4970a52c69
--- /dev/null
+++ b/extern/libpng/contrib/powerpc-vsx/README
@@ -0,0 +1,81 @@
+OPERATING SYSTEM SPECIFIC POWERPC DETECTION
+--------------------------------------------
+
+Detection of the ability to execute POWERPC on processor requires
+operating system support.  (The information is not available in user mode.)
+
+Currently only this feature is supported only for linux platform.
+
+HOW TO USE THIS
+---------------
+
+This directory contains C code fragments that can be included in powerpc/powerpc_init.c
+by setting the macro PNG_POWERPC_VSX_FILE to the file name in "" or <> at build
+time.  This setting is not recorded in pnglibconf.h and can be changed simply by
+rebuilding arm/arm_init.o with the required macro definition.
+
+For any of this code to be used the POWERPC code must be enabled and run time
+checks must be supported.  I.e.:
+
+#if PNG_POWERPC_VSX_OPT > 0
+#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-powerpc-vsx=check
+
+FILE FORMAT
+-----------
+
+Each file documents its testing status as of the last time it was tested (which
+may have been a long time ago):
+
+STATUS: one of:
+   SUPPORTED: This indicates that the file is included in the regularly
+         performed test builds and bugs are fixed when discovered.
+   COMPILED: This indicates that the code did compile at least once.  See the
+         more detailed description for the extent to which the result was
+         successful.
+   TESTED: This means the code was fully compiled into the libpng test programs
+         and these were run at least once.
+
+BUG REPORTS: an email address to which to send reports of problems
+
+The file is a fragment of C code. It should not define any 'extern' symbols;
+everything should be static.  It must define the function:
+
+static int png_have_vsx(png_structp png_ptr);
+
+That function must return 1 if POWERPC_VSX instructions are supported, 0 if not.
+It must not execute png_error unless it detects a bug.  A png_error will prevent
+the reading of the PNG and in the future, writing too.
+
+BUG REPORTS
+-----------
+
+If you mail a bug report for any file that is not SUPPORTED there may only be
+limited response.  Consider fixing it and sending a patch to fix the problem -
+this is more likely to result in action.
+
+CONTRIBUTIONS
+-------------
+
+You may send contributions of new implementations to
+png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+possible.  Obviously OS dependencies are to be expected.  If you submit code you
+must have the authors permission and it must have a license that is acceptable
+to the current maintainer; in particular that license must permit modification
+and redistribution.
+
+Please try to make the contribution a single file and give the file a clear and
+unambiguous name that identifies the target OS.  If multiple files really are
+required put them all in a sub-directory.
+
+You must also be prepared to handle bug reports from users of the code, either
+by joining the png-mng-implement mailing list or by providing an email for the
+"BUG REPORTS" entry or both.  Please make sure that the header of the file
+contains the STATUS and BUG REPORTS fields as above.
+
+Please list the OS requirements as precisely as possible.  Ideally you should
+also list the environment in which the code has been tested and certainly list
+any environments where you suspect it might not work.
diff --git a/extern/libpng/contrib/powerpc-vsx/linux.c b/extern/libpng/contrib/powerpc-vsx/linux.c
new file mode 100644
index 0000000000..32ed9d7491
--- /dev/null
+++ b/extern/libpng/contrib/powerpc-vsx/linux.c
@@ -0,0 +1,57 @@
+/* contrib/powerpc-vsx/linux.c
+ *
+ * Copyright (c) 2017 Glenn Randers-Pehrson
+ * Written by Vadim Barkov, 2017.
+ * Last changed in libpng 1.6.29 [March 16, 2017]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * STATUS: TESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_vsx implemented for Linux by reading the widely available
+ * pseudo-file /proc/cpuinfo. 
+ *
+ * This code is strict ANSI-C and is probably moderately portable; it does
+ * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "png.h"
+
+#ifndef MAXLINE
+#  define MAXLINE 1024
+#endif
+
+static int
+png_have_vsx(png_structp png_ptr)
+{
+   FILE *f;
+
+   const char *string = "altivec supported";
+   char input[MAXLINE];
+   char *token = NULL;
+
+   PNG_UNUSED(png_ptr)
+
+   f = fopen("/proc/cpuinfo", "r");
+   if (f != NULL)
+   {
+      memset(input,0,MAXLINE);
+      while(fgets(input,MAXLINE,f) != NULL)
+      {
+         token = strstr(input,string);
+         if(token != NULL)
+            return 1;
+      }
+   }
+#ifdef PNG_WARNINGS_SUPPORTED
+   else
+      png_warning(png_ptr, "/proc/cpuinfo open failed");
+#endif
+   return 0;
+}
diff --git a/extern/libpng/contrib/powerpc-vsx/linux_aux.c b/extern/libpng/contrib/powerpc-vsx/linux_aux.c
new file mode 100644
index 0000000000..7828acafb8
--- /dev/null
+++ b/extern/libpng/contrib/powerpc-vsx/linux_aux.c
@@ -0,0 +1,34 @@
+/* contrib/powerpc-vsx/linux_aux.c
+ *
+ * Copyright (c) 2017 Glenn Randers-Pehrson
+ * Written by Vadim Barkov, 2017.
+ * Last changed in libpng 1.6.29 [March 16, 2017]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * STATUS: TESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_vsx implemented for Linux by using the auxiliary vector mechanism.
+ *
+ * This code is strict ANSI-C and is probably moderately portable; it does
+ * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ */
+
+#include "sys/auxv.h"
+#include "png.h"
+
+static int
+png_have_vsx(png_structp png_ptr)
+{
+   unsigned long auxv = getauxval(AT_HWCAP);
+
+   PNG_UNUSED(png_ptr)
+
+   if(auxv & (PPC_FEATURE_HAS_ALTIVEC|PPC_FEATURE_HAS_VSX))
+      return 1;
+   else
+      return 0;
+}
diff --git a/extern/libpng/contrib/testpngs/crashers/bad_iCCP.png b/extern/libpng/contrib/testpngs/crashers/bad_iCCP.png
new file mode 100644
index 0000000000000000000000000000000000000000..0b7b863795ac5c70bb618927bc32813d455667a8
GIT binary patch
literal 321
zcmeAS@N?(olHy`uVBq!ia0y~yP*@FQGjae4hDL$(qd>Murn7T^X0kE^gT!U+goHiE
z7+8F`czBK)PI7(c*f&vdVj$NWacd*ViiUueMoq(=I~o|7B=-K5iM`t#qbwP4V0$)C
zkHV{+>%tpWTQO%ks7u0uB`1_QQ&I{ph{4c;i*UeM2nNhJD}<1ws&T&LR*&M7y`9BD
z?)x?ay~v=z>zP>)<m~984)PxVw@zkBNhx<HNk+dQ$-3eINl69<NdcftIWq$n7Xy-6
P7))7+2+)QI7sn6)wCX|k

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/badadler.png b/extern/libpng/contrib/testpngs/crashers/badadler.png
new file mode 100644
index 0000000000000000000000000000000000000000..2bcbcc926ab7fc7d62a840d19ab0cbb94987d432
GIT binary patch
literal 67
zcmeAS@N?(olHy`uVBq!ia0vp^j35jm7|ip2ssJf2PZ!4!j_b(@3=FH+t~KHln|%W)
O%HZkh=d#Wzp$Pzj0}e3&

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/badcrc.png b/extern/libpng/contrib/testpngs/crashers/badcrc.png
new file mode 100644
index 0000000000000000000000000000000000000000..45d02680454eb3e343a6cb1113fa1d50c18898b7
GIT binary patch
literal 67
zcmeAS@N?(olHy`uVBq!ia0vp^j35jm7|ip2ssJf2PZ!4!j_b(@KsFNt<Lb3%jDRc#
MPgg&ebxsLQ0A+LxyZ`_I

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/empty_ancillary_chunks.png b/extern/libpng/contrib/testpngs/crashers/empty_ancillary_chunks.png
new file mode 100644
index 0000000000000000000000000000000000000000..d76477c6a86f3f60ab785c05cecac3ad6bc31a99
GIT binary patch
literal 730
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn)ga3`ySZE=;=j{(;!Z9znj}_C*$f
z*r^eoX{Rcuvw+y?j=qkY9&VQhu`@h_Lt=S#kAm2l&dvc#J0<PF?2w2O&8y7~Aa+)%
zU-sns9kZcq?-hbGf<f#8XGfoP>+PR`*&dO_)7n#$LF{6n_#UYV9AI{UPYBD7Y%4H3
z$lXam=JGi(JH$1}THx+15WB=RqGX!W(N-|q)7SN<@vZY9b`{VK*_G8FflOwgF|G{^
v4XeK|tpZ66Q*Uy4x;Tb#Tu)8_dXb5N@sZ*lV<2m|`j)}d)z4*}Q$iB}2@uDU

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_IDAT.png b/extern/libpng/contrib/testpngs/crashers/huge_IDAT.png
new file mode 100644
index 0000000000000000000000000000000000000000..efee66cf369959441e1737c5798fd5481b25b830
GIT binary patch
literal 79
zcmeAS@N?(olHy`uVBq!ia0vp^Od!kwBL7~QRc!zN|9?*x#}JO|$$#n}m@qRl3j;9_
ZFvwkF>U&qmrVUic;OXk;vd$@?2>|7F6gmI^

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_bKGD_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_bKGD_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..fd571fd2c93a2e7fe0f510d752a6e50766a6ee14
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|NnoIx4R3I?!A9NAqG!ZKbLh*
G2~7Y_@D6nV

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_cHRM_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_cHRM_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..698e7c46dd7c26f98076301cb533121a4a88600f
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|NnooN09HgeUU{#AqG!ZKbLh*
G2~7Z5hYtGy

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_eXIf_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_eXIf_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..7d4160196686cb0433d965ef67af2aa749895e87
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nnn#glF2R%IPdXAqG!ZKbLh*
G2~7Y}=?;7V

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_gAMA_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_gAMA_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..b089c1859710c5d8a7f72b8bde95320039d10589
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nnowqp#zphuh_WLJXd+elF{r
G5}E*3<_^&S

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_hIST_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_hIST_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..6d6fcb53343aa7a5c356e49a690ef5ad656758d6
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nno6XK+X?ukKNx5QC?ypUXO@
GgeCw;XAR~6

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_iCCP_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_iCCP_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..fbcb7615395e78a2233c05a6d85779fb70abd21a
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nnocvva`GPDwkU5QC?ypUXO@
GgeCw=b`ACb

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_iTXt_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_iTXt_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..098262017efb2dbb89eff3e6542e38f99ef98535
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|NnnxNJNR|)#e7E5QC?ypUXO@
GgeCx0aSpry

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_juNK_unsafe_to_copy.png b/extern/libpng/contrib/testpngs/crashers/huge_juNK_unsafe_to_copy.png
new file mode 100644
index 0000000000000000000000000000000000000000..0cb106f4a2b2cd74bf5277d7c89c19a0a15006ca
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nnnhsh{@>!5P6oAqG!ZKbLh*
G2~7Y`+zw6v

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_juNk_safe_to_copy.png b/extern/libpng/contrib/testpngs/crashers/huge_juNk_safe_to_copy.png
new file mode 100644
index 0000000000000000000000000000000000000000..85252b7dc54b1ccd6e4d2911f6d7f2f6a94635e9
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|NnnhsbBWw`W>@@LJXd+elF{r
G5}E*9h7T_Q

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_pCAL_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_pCAL_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..bc12a8f247357b98c7458131ff00884d1ba19cf1
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nno1v!l<t_4dzzLJXd+elF{r
G5}E*501os3

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_pHYs_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_pHYs_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..343b977e9dfef956480292eaf331852e74c3a95f
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nno1M`ZD|_S9sc5QC?ypUXO@
GgeCw~I}V!w

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_sCAL_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_sCAL_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..61f2f824d1ca584d6c3c702ceb3d23bc2804d391
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nnonv!l-*sR<lFAqG!ZKbLh*
G2~7Y=i4Efb

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_sPLT_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_sPLT_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..75d383a2e47de61ac4f5cdaf4204127fa1d4d16c
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nnn+fKLd^j%+KS5QC?ypUXO@
GgeCw=6b<$O

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_sRGB_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_sRGB_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..bc1db336308fcb8173fad4804b72015b9154c86b
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nnn+kh_zB%;j@HAqG!ZKbLh*
G2~7Y^ehy6l

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_sTER_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_sTER_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..39219fed73f57b1ffbc38eee696a8e6c1fcce944
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nnn+h-;9wz};CuAqG!ZKbLh*
G2~7Y_bPiGg

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_tEXt_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_tEXt_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..947fc373e41b8455f79ecc15d0da4ccc906819cc
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nno9YedO3r=zVvAqG!ZKbLh*
G2~7Z3Kn~de

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_tIME_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_tIME_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..16452fba26e7573a49df0a7e91617804c3de69f8
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|Nno9r?2Zz<6Gx}LJXd+elF{r
G5}E*A-Vas)

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/crashers/huge_zTXt_chunk.png b/extern/libpng/contrib/testpngs/crashers/huge_zTXt_chunk.png
new file mode 100644
index 0000000000000000000000000000000000000000..52f0953089415c495b5790338ae9b490e20c2301
GIT binary patch
literal 57
zcmeAS@N?(olHy`uVBq!ia0vp^j3CU&3?x-=hn=$j|NnngNJL3?W%Wm(5QC?ypUXO@
GgeCx5&JP>_

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-1-1.8-tRNS.png b/extern/libpng/contrib/testpngs/gray-1-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..0fc6cb7dba1b9907a4f4973940cd7e6718c83924
GIT binary patch
literal 325
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y2qYNpL^`PhDVB6cUq_%&>E_A%I)HqIWRD<U
z28Jp%28M<f28Lfip@tU>45bDP46hOx7_4S6Fo+k-*%fF5lwc|e@(Tv)o$_}bkf&4P
z8d2h$Ur<?;nVwO?uu{Ruz|dF+NSG>k<!9t6IG5(-W#*-4B<3nO<(KEA7S)y%{{!kP
z$qb1o@ySe1%_{~<GcYow<}omET-WXK<!e?DXkGv55u?oR-02m9Ez`Y}cp5iy`>*GW
zt+&@s=DH`5$aTB3D$kv(V^*!!ikyPpdzbnPW^JC<*S@(VsVMJYcHA=lvdy>dD?NPQ
zw(#7oeMWuB8sf80T|U8UY^2q6W5!ybFB!NzT^vI=t|y-W21_18Zp4STD}bU5p00i_
I>zopr07Fe_=>Px#

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-1-1.8.png b/extern/libpng/contrib/testpngs/gray-1-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..5db4d7915c600289a83979832b122d4989cf398d
GIT binary patch
literal 311
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y2qYNpL^`PhDVB6cUq_%&>E_A%I)HqIWRD<U
z28Jp%28M<f28Lfip@tU>45bDP46hOx7_4S6Fo+k-*%fF5l+Y=0jVN)>FQ_caOwTA`
zSgBxSU}&rZBuo{&@-y-joJ;faGV{_i5_1)t^2>8li)u@X{{i)tWQIhP_+%!h<`n~_
z85kK-^B5R7uIu*r@--_6w66d3h*4&D?(_=5mg!zfJdGQ<{nvBG*4t|*bKR3j<htEi
zmFLdYF{@T<MNUEQy-WQCvo=rbYu{XwRFroxJ8l_&+2&jKl^(utTX^o)KBK;54e{Bh
wE}!5vHqvUkF=H*zUkqHHE{-7_*ON~G10s(hH{!$F6+lr2Pgg&ebxsLQ00i4+KL7v#

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-1-linear-tRNS.png b/extern/libpng/contrib/testpngs/gray-1-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..5beb9d1df2026d6a63ecbf733dd86ff238e41aea
GIT binary patch
literal 325
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y2qYNpL^`PhDVB6cUq=SUwgrYSro{vK3dtTp
zz6=aiY77hwEes65fI<x~7#K<o7#Ln9FfdrnU|<k0n6oR;1}MQ)666;QG;Ye@bwHj@
ziEBiObACZ(QD%BZ3ByVSBLhQY9Ux(<;FX_|r{G+gmzSBBo{^ZV;FMpUlUh_;Qv467
zuOu@hqQoaNIW?~sD9ymgkebK9z;Ru-$Cs~JL7;X0r$>x3yK|>k2)0c3QsQac$nC$L
zGq&DdJDKaAL?YMi&Z<0ju8vu?S}Sr2dhcE8FPOD?T3`F-lBA-%gV}M*_{%omy07%`
zecQrwxAqzJC2NS!K6Uv7ud$I<(~TKxfxcwm@^o<w;kcfB0vIfL47m{>-mU<OGI+ZB
KxvX<aXaWFxsA?Mk

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-1-linear.png b/extern/libpng/contrib/testpngs/gray-1-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..36a89a5abb65bc26902168e4354f9b7a0a058129
GIT binary patch
literal 311
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y2qYNpL^`PhDVB6cUq=SUwgrYSro{vK3dtTp
zz6=aiY77hwEes65fI<x~7#K<o7#Ln9FfdrnU|<k0n6oR;1}LFZ;u=xnoL^8`l$oAU
z!mv`o$iUE82S}JIc;#p0DL9wr<z?ojXC&q-IOUh;q!!hd6#oP2E6EIrDDlZmPR%O@
zN;5Drq~<X&a9r2z@#Sk)5NKWh=@FyM?%e4Wf-Td%lz199a{I66jIFoVPUgBNk;rws
zvntP>t7BHJ){2~h-g}q&3ubMe*4MtdB&jIxV0PRx{<6)t?khcf-?s4Ft$jv)$r|Fb
xPhCF2Yiy*|bYsR^puZTnJY5_^IIbt300u-JLvF-}w=00644$rjF6*2UngBX_W^n)j

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-1-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/gray-1-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..80cec4b5eda87dbb62339094799b5ee2992cc539
GIT binary patch
literal 278
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y2qYNpL^`R1IK@HkPR!=VeS?7<rjj7PV4(bz
zzw3ZJof6lG66gGa%A(Blj1q>G3PuKo#yUX4RKY7hBTvD(G%qhRFFhkMSHUU2JSVlN
zwxswUP+v)ANJNQGW^!s?F;JR;ks&pYfq~<?ZjUctvw}eD`cID-Wp?LIuMljR?xn=j
zxRKj`J!fpay>>F!J&8oF+nrT;?pz(SYPDA66!hM^)L$@b^R&M9%_T`ic?YxOmhqQu
zzI9*e;rq6Q=WgvY>PyxTpMC1`30`9(t)?3@)~W&R=kj!M4B@z*d;;jtJcite4{uih
PMHxI@{an^LB{Ts56k%Qg

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-1-sRGB.png b/extern/libpng/contrib/testpngs/gray-1-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..484fd18c4f64f1166bc8d27840187c7334471fde
GIT binary patch
literal 264
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y2qYNpL^`R1IK@HkPR!=VeS?7<of6lG66gGa
z%A(Blj1q>G3PuKo#yUX4RKY7hBTvD(G%qhRFFhkMSHUU2JSVlNwxswUP+v)ANJNQG
zW^!s?F;JR;ks&pYfq~<?ZjUctvw}eD`cID-Wp?LIuMljR?xn=jxRKj`J!fpay>>F!
zJ&8oF+nrT;?pz(SYPDA66!hM^)L$@b^R&M9%_T`ic?YxOmhqQuzI9*e;rq6Q=WgvY
z>PyxTpMC1`30`9(t)?3@)~W&R=kj!M4B@z*d;;jRJcite4{uihMHxI@{an^LB{Ts5
De4koZ

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-1-tRNS.png b/extern/libpng/contrib/testpngs/gray-1-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..a988db9686e25a1abbc150bc6cc92c62e5647a50
GIT binary patch
literal 265
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y2qYNpL^`R11WJPZf`LL){;mV^bV^(!N}Tfx
zDvL7HGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$
znaQbn#XxBWMuyZp1_qAnx;?&p%?bjo>pwkWl-Zp-y+W{Mx|b49<3?`(^_;Qw_S(r@
z_aqXzZg*DYxpQ^Qs?}PNQ_y?wQh&j$&C~kYH<u(8<sHn9TgG3u`PO}<hws}Kp1ZZr
zs4rPVeD<l!CwPsGw3=?rSgQuKpUcz5F@)oK@(G~V@)&X>KD=E46lL&q^>bP0l+XkK
DA>~^U

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-1.png b/extern/libpng/contrib/testpngs/gray-1.png
new file mode 100644
index 0000000000000000000000000000000000000000..71e37a336385e6432e94a7d9ff63ee51450e082a
GIT binary patch
literal 251
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y2qYNpL^`PhDV-A6h!W@gg36-I^o$aQl?p}%
zhQ>NT!c@U4KO;}Uxil{?GcP?OF;~GUzdR?ksJ5i|A5dROW=KSdPiAszUNKObfsr9K
zkAZ>Xx^9mzU$cTh>-tZR7-e?nPOlJbneL^;)3}k_e?4bxy}foa*FA|uuG^hedG1^t
zvud?g<P`MYyVPGWYxA_e_RS?pMR^Ca<CgK4ZN7D1>EZjfh39VVGwMs$5TAYO@(EsJ
sBdw+zGuEmB?dS4zaSY+Oo_qr6nLLKvh!1a907V%*UHx3vIVCg!0JB3^X8-^I

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-16-1.8-tRNS.png b/extern/libpng/contrib/testpngs/gray-16-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..06cc0c138e80cf81da4acfe4e1dcfacf5a392c0e
GIT binary patch
literal 744
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583ceNgJ!4pPawsT?&#~tz{ps-dGfvvAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn<#yFFbTLn>~)y<`Xs501kdc>gb|{OBOXoxAG1@2PY)0|vGO
v3=#~?2@E_9j04OW6pnxd!vKc_*b&#6jwCVjmF-a8!2krFu6{1-oD!M<TJNvD

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-16-1.8.png b/extern/libpng/contrib/testpngs/gray-16-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..06cc0c138e80cf81da4acfe4e1dcfacf5a392c0e
GIT binary patch
literal 744
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583ceNgJ!4pPawsT?&#~tz{ps-dGfvvAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn<#yFFbTLn>~)y<`Xs501kdc>gb|{OBOXoxAG1@2PY)0|vGO
v3=#~?2@E_9j04OW6pnxd!vKc_*b&#6jwCVjmF-a8!2krFu6{1-oD!M<TJNvD

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-16-linear-tRNS.png b/extern/libpng/contrib/testpngs/gray-16-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..beb4e96e25f70241098b8427adadfbdbe2c4bdf0
GIT binary patch
literal 744
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583ceNgJ!4pPawsT?&#~tz}U9H@Wr%vAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn<#yFFbTLn>~)y<`Xs501kdc>gb|{OBOXoxAG1@2PY)0|vGO
v3=#~?2@E_9j04OW6pnxd!vKc_*b&#6jwCVjmF-a8!2krFu6{1-oD!M<<sh%`

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-16-linear.png b/extern/libpng/contrib/testpngs/gray-16-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..beb4e96e25f70241098b8427adadfbdbe2c4bdf0
GIT binary patch
literal 744
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583ceNgJ!4pPawsT?&#~tz}U9H@Wr%vAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn<#yFFbTLn>~)y<`Xs501kdc>gb|{OBOXoxAG1@2PY)0|vGO
v3=#~?2@E_9j04OW6pnxd!vKc_*b&#6jwCVjmF-a8!2krFu6{1-oD!M<<sh%`

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-16-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/gray-16-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..315db86a6ad80b29e14ab131535c2839cb919124
GIT binary patch
literal 697
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583ceNgJ!4pPY|y-$lZzA{J3v0kfT%L8d2h$
zUr<?;nVwO?uu{Ruz|dF+NSG>k<!9t6IG5(-W#*-4B<3nO<(KEA7S)y%{{!kP$qb1o
z@ySe1%_{~<18qpnV_@L8uG{0w*Q_AWy8hE6Mw#8Y(<=m9rh6&zG;ZYfU(Xp^Z?B!q
zbx$IZ>vm^Vo;z2^tXi!VIR(A<F7+48+B~hVeRD}tQQpDqxMlohn{VA$dicI=;kjG;
zjQWx_#Alzne1g~5NUQ0_jJ0Y&KkW8&aSW-r_4bk>(1RR@H}L*nRQb_CiaU4JdEZm%
zYz7Q$2N)z6m=hRy8W;zdGbkJZ35Ed<39uusGaX4{<}2Hwyn_J<JYD@<);T3K0RW*z
BqtyTa

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-16-sRGB.png b/extern/libpng/contrib/testpngs/gray-16-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..315db86a6ad80b29e14ab131535c2839cb919124
GIT binary patch
literal 697
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583ceNgJ!4pPY|y-$lZzA{J3v0kfT%L8d2h$
zUr<?;nVwO?uu{Ruz|dF+NSG>k<!9t6IG5(-W#*-4B<3nO<(KEA7S)y%{{!kP$qb1o
z@ySe1%_{~<18qpnV_@L8uG{0w*Q_AWy8hE6Mw#8Y(<=m9rh6&zG;ZYfU(Xp^Z?B!q
zbx$IZ>vm^Vo;z2^tXi!VIR(A<F7+48+B~hVeRD}tQQpDqxMlohn{VA$dicI=;kjG;
zjQWx_#Alzne1g~5NUQ0_jJ0Y&KkW8&aSW-r_4bk>(1RR@H}L*nRQb_CiaU4JdEZm%
zYz7Q$2N)z6m=hRy8W;zdGbkJZ35Ed<39uusGaX4{<}2Hwyn_J<JYD@<);T3K0RW*z
BqtyTa

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-16-tRNS.png b/extern/libpng/contrib/testpngs/gray-16-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..4826d61eb7fab6977de0135762596f6220847a51
GIT binary patch
literal 684
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583ceNgJ!4pPavgJ;u=xnoL^8`l$oAU!mv`o
z$iUE82S}JIc;#p0DL9wr<z?ojXC&q-IOUh;q!!hd6#oP2E6EIrDDlZmPR%O@N&^i|
z&0}ETxUSpd%h#+R(7OK9BSx9sxzj5ITc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On
z$E;ed6*&dH_b&Ap%-TGyuYGe#Qc>Q)?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy
z*hs7C#*DRUKu_%Uba4!+xb^muA<$18hd1#4UsU<gL5e$f)p_4j>1+lJYzG)57?=|n
qcp4Z7m@_CG0SSfy4hgU$t}`7;V&*H`p}d0u2s~Z=T-G@yGywqIAfV*{

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-16.png b/extern/libpng/contrib/testpngs/gray-16.png
new file mode 100644
index 0000000000000000000000000000000000000000..4826d61eb7fab6977de0135762596f6220847a51
GIT binary patch
literal 684
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583ceNgJ!4pPavgJ;u=xnoL^8`l$oAU!mv`o
z$iUE82S}JIc;#p0DL9wr<z?ojXC&q-IOUh;q!!hd6#oP2E6EIrDDlZmPR%O@N&^i|
z&0}ETxUSpd%h#+R(7OK9BSx9sxzj5ITc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On
z$E;ed6*&dH_b&Ap%-TGyuYGe#Qc>Q)?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy
z*hs7C#*DRUKu_%Uba4!+xb^muA<$18hd1#4UsU<gL5e$f)p_4j>1+lJYzG)57?=|n
qcp4Z7m@_CG0SSfy4hgU$t}`7;V&*H`p}d0u2s~Z=T-G@yGywqIAfV*{

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-2-1.8-tRNS.png b/extern/libpng/contrib/testpngs/gray-2-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..a1c6854c96cac7f43c66695fcb529ede2d6d5d34
GIT binary patch
literal 325
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c21SA-yJ@?oE5=eLSb!1><EZsbLUk8w{kn9oU
z%fL{j#=y|f!octgDAe$RfuYoZf#FpG1B2BJ1_tqhIlBUFfD%k4L4LtNy;J_K1M+lA
zTq8=H^9w4AGSf3k7*;A685kPt00~nCul$TW1?SSdyv)4xjKo|8r~LAq)S}vw;(tJW
zC7B@+B|e$Ssd>dfX$D4y)I0_Tj_bNTzI@FJ0<G&mJz|vEojbikuw}ZJ5>MksZvXY1
zvGw-a$z1m&61i@7R^_>Kb<C>OT9H%Gd+$<z!K}^G`r0>_Bo*Zy%#K^eU$*(yeWi!*
z+ZLX?wa=(8SwnpGsmmvLjg7RLZp>H<^d$qAr;B3<$Mxh1Yzz#t3^FQJZ<B$d44$rj
JF6*2UngAcCX#W5J

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-2-1.8.png b/extern/libpng/contrib/testpngs/gray-2-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..4cc811cdf7eacddc22bbae8eca6813c5783418ac
GIT binary patch
literal 311
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c21SA-yJ@?oE5=eLSb!1><EZsbLUk8w{kn9oU
z%fL{j#=y|f!octgDAe$RfuYoZf#FpG1B2BJ1_tqhIlBUFfD$?-t`Q~9`303lnduoN
z3@a6k3=EBRfP|@nSAIsGf^%tJUS?i;Mq;jlQ+|0)YEf-T@jsxxlFX2Z5}(ZE)VyM#
zGy@|;Y90dv$93HvU%qAqf!6h(9x=-7&YfN%*fQNqiKlTRxBq(1*m`^IWUhM>iCnik
ztMc5rI%d^st;i|py?3d<VAkeoeeIh|l8W*UX2&h#FWY?UzS6_@Z41xc+Go_4tRX)8
x)a4Vr#ztCAH)gB_`ip_f)5S4_<9hN0HU<V+1{syAx5+?J22WQ%mvv4FO#sz8WmNzG

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-2-linear-tRNS.png b/extern/libpng/contrib/testpngs/gray-2-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..3c29ec6d97ac694615d5081ad650a348a1ead652
GIT binary patch
literal 325
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c21SA-yJ@?oE5=eLSb!1>{TVVKNT0D@ikn9oU
z%fL{j#=y|f!octgDAe$RfuYoZf#FpG1B2BJ1_tqhIlBUFfD%k4L4LsujEqzMt^@LP
zN?apKobwARi!#$QN*Gou7#SEE>i`K;1+V;!JO$^{yu8f3^o+z@1*iP-oYbP)lHz|r
zeI=P85hXsE$*Fn8Kxqa>hSWR;29E2xJ-&R+3IeU`KRsfU*_}JRLa=4Jml99oMsEN0
zoU!%x+R0q^Boeu9cUI-Ob9KzB)mo8L(0lJvf5EKH)B4&smn0SC9n6kf#$UGi)_tXi
z@7orhyS2}#FIhu;_NmJ!c#Vy;nr_Tk3-l!em#2$k2*>s032Y1uvJ5gRRd17lq70s{
KelF{r5}E*50%<V-

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-2-linear.png b/extern/libpng/contrib/testpngs/gray-2-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..6ca6fb74dd865fdc8272190027938252c613254a
GIT binary patch
literal 311
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c21SA-yJ@?oE5=eLSb!1>{TVVKNT0D@ikn9oU
z%fL{j#=y|f!octgDAe$RfuYoZf#FpG1B2BJ1_tqhIlBUFfD$?-t`Q~9`303lnduoN
z3@a6k3=EBRfP|@nSAIsGf^%tJUS?i;Mq;jlQ+|0)YEf-T@jsxxlFX2Z5}(ZE)VyM#
zGy@|;Y90dv$93HvU%qAqf!6h(9x=-7&YfN%*fQNqiKlTRxBq(1*m`^IWUhM>iCnik
ztMc5rI%d^st;i|py?3d<VAkeoeeIh|l8W*UX2&h#FWY?UzS6_@Z41xc+Go_4tRX)8
x)a4Vr#ztCAH)gB_`ip_f)5S4_<9hN0HU<V+1{syAx5+?J22WQ%mvv4FO#lk$WrqL&

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-2-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/gray-2-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..b418c8fbb600a1991f4e19147c95c5f2856e1310
GIT binary patch
literal 278
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c21SA-yJ@?oE;uHtDJ29Id_YDSem`Z~Df*BYY
zr~F+9<mr^SMwB?`7gQEyre~BetW+>EFf`Ty5~d1X`5Ac%&ZT*InR)3MiMa|+`Q<sO
zMYScx|A6{RGD9Ltd@_?$^NNAe42%q^c?=93*L8b*`I;33TGxMi#3-{ncY1|j%XBX#
zp2m&b{_8no>+Q9Zx$a3Ma^3E%%5&%Hm{qH_BB!AD-lhJ6S(~TzwQnv-D#|;U9k-0X
zZ1b)AN)O++Ej)K?pHW}3hWPALmrw8-8)-G&n6Xw3Xg`;yi(?4K_2da`3=FaiGAdPX
QlYycPp00i_>zopr0LZ3Y7XSbN

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-2-sRGB.png b/extern/libpng/contrib/testpngs/gray-2-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..a6bde60afe4a37ac48cac5461c8e7ffd015c4940
GIT binary patch
literal 264
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c21SA-yJ@?oE;uHtDJ29Id_YDSebV^(!N}Tfx
zDvL7HGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$
znaQbn#XxBWMuyZp1_qAnx;?&p%?bjo>pwkWl-Zp-y+W{Mx|b49<3?`(^_;Qw_S(r@
z_aqXzZg*DYxpQ^Qs?}PNQ_y?wQh&j$&C~kYH<u(8<sHn9TgG3u`PO}<hws}Kp1ZZr
zs4rPVeD<l!CwPsGw3=?rSgQuKpUcz5F@)oK@&q;p23ZCfm8!SNKv4!yS3j3^P6<r_
DB?nn;

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-2-tRNS.png b/extern/libpng/contrib/testpngs/gray-2-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..8e04cb5020cc1ecf62544cb32d5b79c80db9eb55
GIT binary patch
literal 265
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c21SA-yJ@?oEq?k&A{DK)68K?YR2juCLxJHyX
z=ND8KWu|A8FsxKCGB7mO0TQMPUile$3eKf@d6{|X8Hu?HPWk0IsYSIV#s7f%N-{$t
zN_;YtQ}c>}(hQ6Ysd)?x9M^SweEFIc1X|aBdc-KRJ9m18V9RtbC7#BO-2Ur1W9#j;
zlez9mBy!#Etjcre>X=olwIZjW_ui%cf?1oV^|fy<Nh-=am>su_zijiZ`$`Yrw=Fz(
zYoAeHvWEEVQ<qQh8XIXf-I%df4QM}?r;B3<$Mxh1Yzz#t3^FQJZ<B$d44$rjF6*2U
FngGifS|<Pi

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-2.png b/extern/libpng/contrib/testpngs/gray-2.png
new file mode 100644
index 0000000000000000000000000000000000000000..9d85a2ace35065acf576c22c315e50366f4fd264
GIT binary patch
literal 251
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c21SA-yJ@?oEq;yJLBTAg}3o45;(=$pKRw@`7
z7#iyU2~!2H{ER#W=hD2q%)IoB#9RfZ{PLXCqS}(;e?WaDnIRD+KAFj>dBs3!21bU|
zJO&1i>$*L@e9a01t?NHMVwBmPJH0}%WxAIVPvb^z|Mi@)_4eAyT=ygrxo&q><+*cp
z%&OH|kyFrn?^1uktj*K<+BcUZ73Cewj$6iGw)xh5rHAj^7M{Dc&!{h1LwxqB%O`k^
sjkKC>%vh@iw4ck<#W95Adh!G|1_oIM8I`KH$v{yCPgg&ebxsLQ08p7$eE<Le

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-4-1.8-tRNS.png b/extern/libpng/contrib/testpngs/gray-4-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..402d699fbc58d06f5dd278de7237e76ed57d2095
GIT binary patch
literal 327
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j0wfsBAI)h3QY`6?zK#rxjHR0=@9O~a6_P!I
zd>I(3)EF2VS{N990fib~Fff!FFfhDIU|_JC!N4G1FlSew4N!uqB*-rqsCUZWbwHj@
ziEBiObACZ(QD%BZ3ByVSBLhQY9Ux(<;FX_|r{G+gmzSBBo{^ZV;FMpUlUh_;Qv467
zuOu@hqQoaNIW?~sD9ymgkebK9z;Ru-$Cs~JL7;X0r$>x3yK|>k2)0c3QsQac$nC$L
zGq&DdJDKaAL?YMi&Z<0ju8vu?S}Sr2dhcE8FPOD?T3`F-lBA-%gV}M*_{%omy07%`
zecQrwxAqzJC2NS!K6Uv7ud$I<(~TKxfxcwm@pN$v;kcfh5&{el=1UA8Pv&%-2Z}Rz
My85}Sb4q9e0OT}lpa1{>

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-4-1.8.png b/extern/libpng/contrib/testpngs/gray-4-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..bc8da98761cf9ecf3b9e0f1195b58a19f672ae5a
GIT binary patch
literal 313
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j0wfsBAI)h3QY`6?zK#rxjHR0=@9O~a6_P!I
zd>I(3)EF2VS{N990fib~Fff!FFfhDIU|_JC!N4G1FlSew4NyX-#5JPCIlrK?C^J2y
zgkhzEk%6JH4v;Wa@XF7~Q*bWL%gfA5&q&NwaLO;wNiC`^DgFo4SCSbLQR0)CoSIh*
zlxARLNX=tl;JB{a<IC5qAke!0(<4Ti-MP~%1Y4$iDe*LJ<n~|B8C!3!oy>JlB9ZHM
zXH}j%SI4Yctra;1z4tEl7tGo`t*?D^Nm5bX!R)wY{AHVO-B)_}zHQ;TTl<Xqk~PF<
zpSpa4*Vss_>Bfw;Kz}jtc)B=-a9mGL2?2%x^CgClCv!T^1H~CUUHx3vIVCg!0F@$V
A_5c6?

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-4-linear-tRNS.png b/extern/libpng/contrib/testpngs/gray-4-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..45c063d8542ccc7429dc4709fa8487244748d9fb
GIT binary patch
literal 327
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j0wfsBAI)h3QY`6?zK#rxZ3_%vOp6Ed6_P!I
zd>I(3)EF2VS{N990fib~Fff!FFfhDIU|_JC!N4G1FlSew4N!uqB*-tAfst{_-*rHq
zPKj$oiF1BIWl?5&MhU}81tSAPV;vx2s^FEMk*DBXnwOWEm!6TBtKgJho|9TsTT=WF
zsIMe5B%;J8GdVS{7%0ua$dH=Hz`$``x5t;SSwWz6{ijEaGP`r9R|vLD_fq0%+{o>}
zo-?-IUOSoVo<t(o?arz^cdm|EwOT833VQEd>MxkJd0Jol=8~kMyo1?s%lOMS-@32#
z@O|6DbGP;x^(AYF&pvhe1h27?R@03cYk|IG;PG^E4B@z*oDu>I59Uh@A5Z3VoCk_C
Nc)I$ztaD0e0stKXYtjG!

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-4-linear.png b/extern/libpng/contrib/testpngs/gray-4-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..0bd068d73fe1cb710b6f1eeed6c34dae1de8d718
GIT binary patch
literal 313
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j0wfsBAI)h3QY`6?zK#rxZ3_%vOp6Ed6_P!I
zd>I(3)EF2VS{N990fib~Fff!FFfhDIU|_JC!N4G1FlSew4NyX-#5JPCIlrK?C^J2y
zgkhzEk%6JH4v;Wa@XF7~Q*bWL%gfA5&q&NwaLO;wNiC`^DgFo4SCSbLQR0)CoSIh*
zlxARLNX=tl;JB{a<IC5qAke!0(<4Ti-MP~%1Y4$iDe*LJ<n~|B8C!3!oy>JlB9ZHM
zXH}j%SI4Yctra;1z4tEl7tGo`t*?D^Nm5bX!R)wY{AHVO-B)_}zHQ;TTl<Xqk~PF<
zpSpa4*Vss_>Bfw;Kz}jtc)B=-a9mGL2?2%x^CgClCv!T^1H~CUUHx3vIVCg!0Lvw4
AC;$Ke

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-4-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/gray-4-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..be8521049c4bd55335297e587ad8679808c193df
GIT binary patch
literal 280
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j0wfsBAI)h3af*Z7otVv!`vwC!OeH~n!3>Oy
zQ~s_4@^ngEBTAg}3o45;(=$pKRw@`77#iyU2~!2H{ER#W=hD2q%)IoB#9RfZ{PLXC
zqS}(;e?WaDnIRD+KAFj>dBs3!21bU|JO&1i>$*L@e9a01t?NHMVwBmPJH0}%WxAIV
zPvb^z|Mi@)_4eAyT=ygrxo&q><+*cp%&OH|kyFrn?^1uktj*K<+BcUZ73Cewj$6iG
zw)xh5rHAj^7M{Dc&!{h1LwxqB%O`k^jkKC>%vh@iw4cY*#W95AdU8q#(1XmE7(SlN
S={OG*XYh3Ob6Mw<&;$T}LSMK5

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-4-sRGB.png b/extern/libpng/contrib/testpngs/gray-4-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..38a79228d93ba2f043ba3edb84d78cd58ea7a6a3
GIT binary patch
literal 266
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j0wfsBAI)h3af*Z7otVv!`vwC!Iwh_VCC>Q;
zl|`B986^xW6^slFjdg&8se)I2MxKImX<lAtUV27iu7Xp3c}{9kZAtMzpuUpKkcbkW
z%;eO(VxTkwBSUH)0|Uo(-5y`QW(9%P^`9Ow%IwaaULn{r-Ajq5aU-|?dd}E-d+lVd
zdlHFUw>zuy+_^et)oQKCDd@d-slQ;>=4pNHn@f_4@(yOlE#oiSeCxi_!}o0q&)wQ*
z)R(LwKKs<=6THSoT1_`*tW^Wr&*SOh7{YNqIVA+>CFV;EA5Z3VoCk_Cc)I$ztaD0e
F0sz(ETn+#L

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-4-tRNS.png b/extern/libpng/contrib/testpngs/gray-4-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..14c4f1fb3aadad1b986d1ff32b99ae5eb50421e5
GIT binary patch
literal 267
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j0wfsBAI)h3QcNX5e!&ckj8p!u1M+lATq8=H
z^9w4AGSf3k7*;A685kPt00~nCul$TW1?SSdyv)4xjKo|8r~LAq)S}vw;(tJWC7B@+
zB|e$Ssd>dfX$D4y)I0_Tj_bNTzI@FJ0<G&mJz|vEojbikuw}ZJ5>MksZvXY1vGw-a
z$z1m&61i@7R^_>Kb<C>OT9H%Gd+$<z!K}^G`r0>_Bo*Zy%#K^eU$*(yeWi!*+ZLX?
zwa=(8SwnpGsmmvLjg7RLZp>J#2DG2Y)5S4_<9c#R2+&W=ml!^t%;`7}6ld^s^>bP0
Hl+XkKeMDTy

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-4.png b/extern/libpng/contrib/testpngs/gray-4.png
new file mode 100644
index 0000000000000000000000000000000000000000..16bcada820e9317d7b3815e635f35201d0574d92
GIT binary patch
literal 253
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j0wfsBAI)h3QaUBB5hc#~1(ija=@}&qD;10k
z42^YwgsFm8eny^xb7@{)W?p(mVy=QyetAx6QEf@_KcK#n%#er@pUmXcykej<10zFf
z9s>i%b=@9czGel1*7ctrG0N=Don9f>GTlpwr*R{<|9Z~YdVB3;u6q)RT(>)`^4z&P
zX4Pt~$SLT(cd5T%*5+w_?VC%Iit-L-$1US8+kET3(!=*{3(wu!XVjOhAwK)m<rBQd
uMp{ibW~@~M+Rx+Z;uyklJvk)==nLjc3?EPCbeso@GkCiCxvX<aXaWHK0$Cma

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-8-1.8-tRNS.png b/extern/libpng/contrib/testpngs/gray-8-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..2b3892458a430c374e0025e7ef87642065aa5600
GIT binary patch
literal 327
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K57&$<sh>`wkAjOjI=<CS9$XL30^1corUm@8e
z$d`ekN{xY`p@o6r7f`6-1p`B=0RzLU1O^7H84L{K1#@-<+5jb(N`m}?fqJL>T?gdp
zl(<HeIOi8s7G<VqlrXGRFfuSS)&UZx3SRjcc?!;@d3l+6=^2T+3QqauIjKdpCB^@M
z`bsiGB1(KRlT-7Gfzm)Hrsgp)a9r2z@#Sk)5NKWh=@FyM?%e4Wf-Td%lz199a{I66
zjIFoVPUgBNk;rwsvntP>t7BHJ){2~h-g}q&3ubMe*4MtdB&jIxV0PRx{<6)t?khcf
z-?s4Ft$jv)$r|FbPhCF2Yiy*|bYsR^pf4GCJY5_^BrYeX$UJ0VXli0)GOYaq^d$p>
Mr>mdKI;Vst0EUNYpa1{>

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-8-1.8.png b/extern/libpng/contrib/testpngs/gray-8-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..4bba74cfa63e2e81fb6b7bc7ad83282cd9b94f8f
GIT binary patch
literal 313
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K57&$<sh>`wkAjOjI=<CS9$XL30^1corUm@8e
z$d`ekN{xY`p@o6r7f`6-1p`B=0RzLU1O^7H84L{K1#@-<+5jbVN?apKobwARi!#$Q
zN*Gou7#SEE>i`K;1+V;!JO$^{yu8f3^o+z@1*iP-oYbP)lHz|reI=P85hXsE$*Fn8
zKxv?(Qu7!XIIipV`0_O?2(+&M^oUVrckc8G!ItS>N<57lx&7C3#@5?wCv)ACNaVWR
zS(WF`)iJA9Yeh~$@4ZX?1+z9!>ucX!l2nv;FgtD;f7#|+_mv*LZ(Dfo);^=YWDW7z
zr!Jr1H8#>}x-nxd&|eHZo-U3d5|@)xWF9gwG&M0Y8P<LQ`ip_V)78&qol`;+07p?}
A_5c6?

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-8-linear-tRNS.png b/extern/libpng/contrib/testpngs/gray-8-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..a801abdaaa756477768c6fcc56a679b597235a2c
GIT binary patch
literal 327
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K57&$<sh>`wkAjOjI=<CS9*tWp%#k6=JUm@8e
z$d`ekN{xY`p@o6r7f`6-1p`B=0RzLU1O^7H84L{K1#@-<+5jb(N`m}?85kL-{9Om+
z>6ExelsM-XR2F5XXOu9kR4_6yG}ZwUrV3v98F>oMrFnUodFdI6xe8AC<vFQEwI#*>
zfci=@Ln2CiGLuvDih<HVC#L2xFmPPg?eXPnRuE`i|LGB<%<kOj6@o3(y_9$wH*)*0
z=Zvkl*G}fTCy~f?yR$0KovUM3t=5X1g5G<V`U_@lp4QjCxg@D5?_hS^GXAp7x9%%F
zeBZY4+^u~^eaRZ)vrk<<!E0=!)pTRVTA(i(csyMkLnJOIr^q~HU}$P$WHPM%0`w&V
NgQu&X%Q~loCIG)iY0>}y

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-8-linear.png b/extern/libpng/contrib/testpngs/gray-8-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..91be367ee5c1ac540bc68888aa4253292636f31d
GIT binary patch
literal 313
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K57&$<sh>`wkAjOjI=<CS9*tWp%#k6=JUm@8e
z$d`ekN{xY`p@o6r7f`6-1p`B=0RzLU1O^7H84L{K1#@-<+5jbVN?apKobwARi!#$Q
zN*Gou7#SEE>i`K;1+V;!JO$^{yu8f3^o+z@1*iP-oYbP)lHz|reI=P85hXsE$*Fn8
zKxv?(Qu7!XIIipV`0_O?2(+&M^oUVrckc8G!ItS>N<57lx&7C3#@5?wCv)ACNaVWR
zS(WF`)iJA9Yeh~$@4ZX?1+z9!>ucX!l2nv;FgtD;f7#|+_mv*LZ(Dfo);^=YWDW7z
zr!Jr1H8#>}x-nxd&|eHZo-U3d5|@)xWF9gwG&M0Y8P<LQ`ip_V)78&qol`;+0DV+u
AC;$Ke

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-8-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/gray-8-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..f54f23d6bc86096cf0268208b903275a35790707
GIT binary patch
literal 280
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K57&$<sh>`wk5T`iE-HF-!xNk6!!&DOF7tFxO
zIOXp;AWx^nHKN2hzo4=xGd-h(VWonRfuXSukT6y7%FoDCa4yZu%gjs9NX%7m$}i7J
zEvhXk{s+`ok{J?F;**)2npX^z2HKgL$H2gGUAM=VuUSE$b^WJDj551(r&kEJO!rda
zY23)|zn(L;-d;PI>z+g+*X_=#Ja?{+S+!a#ateCyUFt8GwRu`!`{t6QqP&CIam)D2
zHs89h^zeP#!gIIw8TBP=h|fNC`2?@Akyg`<8Ee&m_VakUIEF}EPEL_|$iUFl#K>e=
S`(*}DoWax8&t;ucLK6U0(_Od#

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-8-sRGB.png b/extern/libpng/contrib/testpngs/gray-8-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..2ae6377ff956395a0e6b948f0236e057db3d3a9e
GIT binary patch
literal 266
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K57&$<sh>`wk5T`iE-HF-!xNk6!qf_D<QR19m
zP+63jo>9WEQo+c;&{zjZm@0VXXXGh3m*(YV=A~yO<|;Vlm*=Dw)s__h1L`Zu42dZ5
z$xKeoD+WpfZAr~zVBol}+vCgEtRT?3{?j8ynccb5D+F7ndnxfWZshh~&ly{9ubs?w
zPa=`)c4t+dJ6Ff7TCEj11-<t!^%u<AJgu*Nb4gNB-ofm+W&CBEZ{1gV_`Yr7xm){;
z`jR!oXP>%!g4ftctLes!wQ4~7c|2VlLnJOIr^q~HU}$P$WHPM%G6N{i;OXk;vd$@?
F2>`uKS`GjJ

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-8-tRNS.png b/extern/libpng/contrib/testpngs/gray-8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..842245f1d9f192857edd85f43f2d8d6ca8874c01
GIT binary patch
literal 267
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K57&$<sh>`wkAjMP?<QL4q$T;QiIv`J{#5JPC
zIlrK?C^J2ygkhzEk%6JH4v;Wa@XF7~Q*bWL%gfA5&q&NwaLO;wNiC`^DgFo4SCSbL
zQR0)CoSIh*lm=Rpn#aJvab35^m#<ktpmqJHM~pJNbEj7bwoLa@;%VH-?Z2Kgw%%Sl
znd_cJBG>KCsyuhDj#;%@D{=~Y?_KIIn6-IYU;E~gq@uio*>TJG%QoM-uk`SJ+ro3V
z_8IjhYlzQ2b@>FZv5{8OjTvjzfcEovx;TbNTux4rdC0)f)WpbSSo>uLP@KWj)z4*}
HQ$iB}V~<+M

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-8.png b/extern/libpng/contrib/testpngs/gray-8.png
new file mode 100644
index 0000000000000000000000000000000000000000..23af27e141a5f6a6dbd411dc738418a087997bb2
GIT binary patch
literal 253
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K57&$<sh>`wkAf;2{8d2h$Ur<?;nVwO?uu{Ru
zz|dF+NSG>k<!9t6IG5(-W#*-4B<3nO<(KEA7S)y%{{!kP$qb1o@ySe1%_{~<0}W2i
zV_@L8uG{0w*Q_AWy8hE6Mw#8Y(<=m9rh6&zG;ZYfU(Xp^Z?B!qbx$IZ>vm^Vo;z2^
ztXi!VIR(A<F7+48+B~hVeRD}tQQpDqxMlohn{VA$dicI=;kjG;jQWx_#Alzne1g~5
uNUQ0_jJ0Y&`*}QF977~7C#T3fWMF7&Vq`L`{W1e6&fw|l=d#Wzp$P!=DOVl<

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-alpha-16-1.8.png b/extern/libpng/contrib/testpngs/gray-alpha-16-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..e0d36b7f09cae81f51467da2b57256438c80f5a5
GIT binary patch
literal 919
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583b5>)Uwxm)&VJ&bVpxD21drx&6D?a0Qm~Z
z9znhg3{`3j3=J&|48MRv4KElNN(~qoUL`OvSj}Ky5HFasE6@fgp;O`-QR19mP+63j
zo>9WEQo+c;&{zjZm@0VXXXGh3m*(YV=A~yO<|;Vlm*=Dw)s__h1L`Zu42dZ5$xKeo
zD+Wpf9h92Kz`$``x5t;SSwWz6{ijEaGP`r9R|vLD_fq0%+{o>}o-?-IUOSoVo<t(o
z?arz^cdm|EwOT833VQEd>MxkJd0Jol=8~kMyo1?s%lOMS-@32#@O|6DbGP;x^(AYF
z&pvhe1h27?R@03cYk~e^%JOt^45_&F_R3D)0}edQj$Zqg|L?nd=&2ObWrpUpDw@X9
zJJ;pMCoJ<@&wNIOL4lzGsE2`rY7CABVFyq&urLTPP>UhJpiX61DggcKM`c$!0R1b&
mNX@VWMGn<HPAwxpJYe6a@^9h76YFIdfWXt$&t;ucLK6U^^PtuM

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-alpha-16-linear.png b/extern/libpng/contrib/testpngs/gray-alpha-16-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..26aa32cee157628a4d03895aadbd4d112d52dfd7
GIT binary patch
literal 919
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583b5>)Uwxm)&VJ&bVpxD2FA7phA*bY1NjQc
z9znhg3{`3j3=J&|48MRv4KElNN(~qoUL`OvSj}Ky5HFasE6@fgp;O`-QR19mP+63j
zo>9WEQo+c;&{zjZm@0VXXXGh3m*(YV=A~yO<|;Vlm*=Dw)s__h1L`Zu42dZ5$xKeo
zD+Wpf9h92Kz`$``x5t;SSwWz6{ijEaGP`r9R|vLD_fq0%+{o>}o-?-IUOSoVo<t(o
z?arz^cdm|EwOT833VQEd>MxkJd0Jol=8~kMyo1?s%lOMS-@32#@O|6DbGP;x^(AYF
z&pvhe1h27?R@03cYk~e^%JOt^45_&F_R3D)0}edQj$Zqg|L?nd=&2ObWrpUpDw@X9
zJJ;pMCoJ<@&wNIOL4lzGsE2`rY7CABVFyq&urLTPP>UhJpiX61DggcKM`c$!0R1b&
mNX@VWMGn<HPAwxpJYe6a@^9h76YFIdfWXt$&t;ucLK6T`VW9{B

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-alpha-16-sRGB.png b/extern/libpng/contrib/testpngs/gray-alpha-16-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..f1e811ba342aa8d90406fb1f1014764b2b7b6a71
GIT binary patch
literal 872
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583b5>)Uwxm)`57%LGDh>=Er@5fgGI@*N775
z{DR7&%=C;BhLs9N28PBuK*ChPD?cMo!MQXqFEcMaBQaOODZe}?wWzkF_#aSTNoGhy
ziBD#7YF;r=8fZgm9s>i%b=@9czGel1*7ctrG0N=Don9f>GTlpwr*R{<|9Z~YdVB3;
zu6q)RT(>)`^4z&PX4Pt~$SLT(cd5T%*5+w_?VC%Iit-L-$1US8+kET3(!=*{3(wu!
zXVjOhAwK)m<rBQdMp{ibW~^0XU|`Dfba4!+xb^nRPTm6!Jj{+>`<DOjyL;%V6w_sf
z=CvxC#?m|2<;N#1^IOk+MukCvp#i9efrDxcjs{@|P`I)%2ry8KA;6$cWmhTy{p&|%
sS2_UwE5k_5umnX8)jduvBR@P~->33#;ldN^Wf*|K)78&qol`;+0FSbi?f?J)

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-alpha-16.png b/extern/libpng/contrib/testpngs/gray-alpha-16.png
new file mode 100644
index 0000000000000000000000000000000000000000..689879737fc6df3cb65e3b210067b9ddbac53a38
GIT binary patch
literal 859
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583b5>)Uwxm)&VJ<64!_l=lp`oqRjM+5{8uu
zMh1q)IzYly!7D!_Pr<n~FE2AMJtHw!!70ByC$*@yr1&3DUrA<2M2Syka%x^NP#S1x
zY90dv$93HvU%qAqf!6h(9x=-7&YfN%*fQNqiKlTRxBq(1*m`^IWUhM>iCniktMc5r
zI%d^st;i|py?3d<VAkeoeeIh|l8W*UX2&h#FWY?UzS6_@Z41xc+Go_4tRX)8)a4Vr
z#ztCAH)gC=V_;y)@^o<wskrs_%1+(`4m`|`Ui+5+@4I{GsT9*?hUT>@n#R&Q*X742
zEc08>d`5*qfuRAYhk=7?42}k22T)M5FbFVEiy^?EPGwgr0R8JnWmh@?{VT&r&9DST
h4%IzQEh9fXVBe?mZ{fld>tz^#z|+;wWt~$(69BnNk^TSx

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-alpha-8-1.8.png b/extern/libpng/contrib/testpngs/gray-alpha-8-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..68883a52d5c6828f5389a43634f81e7ad5f158ef
GIT binary patch
literal 744
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K588}#g)VJz{w?K*|-O<;PfswIv^W=RUK)yn<
zN02WALzNl>LqiJ#!!Mvv!wUw6QUeBtR|yOZRx=nF#0%!^3bX-A=#;odlsM-XR2F5X
zXOu9kR4_6yG}ZwUrV3v98F>oMrFnUodFdI6xe8AC<vFQEwI#*>fci=@Ln2CiGLuvD
zih<HV2c_mQFmPPg?eXPnRuE`i|LGB<%<kOj6@o3(y_9$wH*)*0=Zvkl*G}fTCy~f?
zyR$0KovUM3t=5X1g5G<V`U_@lp4QjCxg@D5?_hS^GXAp7x9%%FeBZY4+^u~^eaRZ)
zvrk<<!E0=!)pTRVTA;recYC@xhE&{od&v+O9vp`^@cv&^`O!g&J9pK2-&5&q1`KQm
w7$g{&6Bu|J7zda$C>#L^h5-%<up_QB9Z6#5E8C&Gg8>LUUHx3vIVCg!0N07Ip#T5?

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-alpha-8-linear.png b/extern/libpng/contrib/testpngs/gray-alpha-8-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..cdc07031d7faddef7b738b60f3035a067bf1a3c4
GIT binary patch
literal 744
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K588}#g)VJz{w?K*|-O<;Pfw66Y;frbUK)yn<
zN02WALzNl>LqiJ#!!Mvv!wUw6QUeBtR|yOZRx=nF#0%!^3bX-A=#;odlsM-XR2F5X
zXOu9kR4_6yG}ZwUrV3v98F>oMrFnUodFdI6xe8AC<vFQEwI#*>fci=@Ln2CiGLuvD
zih<HV2c_mQFmPPg?eXPnRuE`i|LGB<%<kOj6@o3(y_9$wH*)*0=Zvkl*G}fTCy~f?
zyR$0KovUM3t=5X1g5G<V`U_@lp4QjCxg@D5?_hS^GXAp7x9%%FeBZY4+^u~^eaRZ)
zvrk<<!E0=!)pTRVTA;recYC@xhE&{od&v+O9vp`^@cv&^`O!g&J9pK2-&5&q1`KQm
w7$g{&6Bu|J7zda$C>#L^h5-%<up_QB9Z6#5E8C&Gg8>LUUHx3vIVCg!0Ab0n(*OVf

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-alpha-8-sRGB.png b/extern/libpng/contrib/testpngs/gray-alpha-8-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..7c37c88836fcb80c0470388e24ff7eae95d7c223
GIT binary patch
literal 697
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K588}#g)VJz{w;*0|kh>GJ`ElQ1AV;UfHKN2h
zzo4=xGd-h(VWonRfuXSukT6y7%FoDCa4yZu%gjs9NX%7m$}i7JEvhXk{s+`ok{J?F
z;**)2npX^z2HKFC$H2gGUAM=VuUSE$b^WJDj551(r&kEJO!rdaY23)|zn(L;-d;PI
z>z+g+*X_=#Ja?{+S+!a#ateCyUFt8GwRu`!`{t6QqP&CIam)D2Hs89h^zeP#!gIIw
z8TBP=h|fNC`2?@Akyg`<8Ee&me%S5l;uunK>+K~&pa(e)Z{YpEsPdzO6nE~b^S-Cj
z*$f!i4lqbCFefnZG%yY@XHYl-5)1<z5@1JMXF8I^%vZKUc?Sa!c)I$ztaD0e0s!;_
Bq`3e9

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/gray-alpha-8.png b/extern/libpng/contrib/testpngs/gray-alpha-8.png
new file mode 100644
index 0000000000000000000000000000000000000000..eb0a92499810b1da4ca73787f7ca610339f40ddc
GIT binary patch
literal 684
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K588}#g)VJz{w?Im##5JPCIlrK?C^J2ygkhzE
zk%6JH4v;Wa@XF7~Q*bWL%gfA5&q&NwaLO;wNiC`^DgFo4SCSbLQR0)CoSIh*lm;4_
zn#aJvab35^m#<ktpmqJHM~pJNbEj7bwoLa@;%VH-?Z2Kgw%%Slnd_cJBG>KCsyuhD
zj#;%@D{=~Y?_KIIn6-IYU;E~gq@uio*>TJG%QoM-uk`SJ+ro3V_8IjhYlzQ2b@>FZ
zv5{8OjTvjzfS%ax>EaktaqI0RL!h5H4sYQ7zo_z~gA{k}s`I|5(%B3c*bXpAFfb=D
q@H8+EFlSIW0ul@Z91>thTxU9x#LQQ=LwN@S5O})!xvX<aXaWEuS)s`Q

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/makepngs.sh b/extern/libpng/contrib/testpngs/makepngs.sh
new file mode 100755
index 0000000000..eb1c15fc95
--- /dev/null
+++ b/extern/libpng/contrib/testpngs/makepngs.sh
@@ -0,0 +1,94 @@
+#!/bin/sh
+#
+# Make a set of test PNG files, MAKEPNG is the name of the makepng executable
+# built from contrib/libtests/makepng.c
+
+# Copyright (c) 2015 John Cunningham Bowler
+
+# Last changed in libpng 1.6.20 [December 3, 2015]
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# The arguments say whether to build all the files or whether just to build the
+# ones that extend the code-coverage of libpng from the existing test files in
+# contrib/pngsuite.
+test -n "$MAKEPNG" || MAKEPNG=./makepng
+opts=
+
+mp(){
+   ${MAKEPNG} $opts $1 "$3" "$4" "$3-$4$2.png"
+}
+
+mpg(){
+   if test "$1" = "none"
+   then
+      mp "" "" "$2" "$3"
+   else
+      mp "--$1" "-$1" "$2" "$3"
+   fi
+}
+
+mptrans(){
+   if test "$1" = "none"
+   then
+      mp "--tRNS" "-tRNS" "$2" "$3"
+   else
+      mp "--tRNS --$1" "-$1-tRNS" "$2" "$3"
+   fi
+}
+
+case "$1" in
+   --small)
+      opts="--small";;&
+
+   --all|--small)
+      for g in none sRGB linear 1.8
+      do
+         for c in gray palette
+         do
+            for b in 1 2 4
+            do
+               mpg "$g" "$c" "$b"
+               mptrans "$g" "$c" "$b"
+            done
+         done
+
+         mpg "$g" palette 8
+         mptrans "$g" palette 8
+
+         for b in 8 16
+         do
+            for c in gray gray-alpha rgb rgb-alpha
+            do
+               mpg "$g" "$c" "$b"
+            done
+            for c in gray rgb
+            do
+               mptrans "$g" "$c" "$b"
+            done
+         done
+      done;;
+
+   --coverage)
+      # Comments below indicate cases known to be required and not duplicated
+      # in other (required) cases; the aim is to get a minimal set that gives
+      # the maximum code coverage.
+      mpg none gray-alpha 8 # required: code coverage, sRGB opaque component
+      mpg none palette 8 # required: basic palette read
+      mpg 1.8 gray 2 # required: tests gamma threshold code
+      mpg 1.8 palette 2 # required: code coverage
+      mpg 1.8 palette 4 # required: code coverage
+      mpg 1.8 palette 8 # error limits only
+      mpg linear palette 8 # error limits only
+      mpg linear rgb-alpha 16 # error limits only
+      mpg sRGB palette 1 # required: code coverage
+      mpg sRGB rgb-alpha 16 # required: code coverage: pngread.c:2422 untested
+      :;;
+
+   *)
+      echo "$0 $1: unknown argument, usage:" >&2
+      echo "  $0 [--all|--coverage|--small]" >&2
+      exit 1
+esac
diff --git a/extern/libpng/contrib/testpngs/palette-1-1.8-tRNS.png b/extern/libpng/contrib/testpngs/palette-1-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..7bf60410d52879bca6b5a3965f040f06e0465630
GIT binary patch
literal 342
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y$P6UUy?J{QNU@|l`Z@xIN;gm5*8$`!Bzpw;
zGB8xBF)%c=FfjZA3N^f7U???UV0e|lz+g3lfkC`r&aOZkpaffhPl)S(28RFt|2xW>
z2m(bIOM?7@862M7NCR?oN?apKobwARi!#$QN*Gou7#SEE>i`K;1+V;!JO$^{yu8f3
z^o+z@1*iP-oYbP)lHz|reI=P85hXsE$*Fn8Kxqa>hSWR;29E2xJ-&R+3IeU`KRsfU
z*_}JRLa=4Jml99oMsEN0oU!%x+R0q^Boeu9cUI-Ob9KzB)mo8L(0lJvf5EKH)B4&s
zmn0SC9n6kf#$UGi)_tXi@7orhyS2}#FIhu;_NmJ!c#Vy;nr_Tk3-mSvm#2$k2*>s0
b6O0TDc?`J`AKtD2iZXb*`njxgN@xNASRHY?

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-1-1.8.png b/extern/libpng/contrib/testpngs/palette-1-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..73965b724e48d70cfff04a965f847929ea97a08e
GIT binary patch
literal 329
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y$P6UUy?J{QNU@|l`Z@xIN;gm5*8$`!Bzpw;
zGB8xBF)%c=FfjZA3N^f7U???UV0e|lz+g3lfkC`r&aOZkpaffhPl)S(28RFt|2xW>
z2m(cPN?apKobwARi!#$QN*Gou7#SEE>i`K;1+V;!JO$^{yu8f3^o+z@1*iP-oYbP)
zlHz|reI=P85hXsE$*Fn8Kxqa>hSWR;29E2xJ-&R+3IeU`KRsfU*_}JRLa=4Jml99o
zMsEN0oU!%x+R0q^Boeu9cUI-Ob9KzB)mo8L(0lJvf5EKH)B4&smn0SC9n6kf#$UGi
z)_tXi@7orhyS2}#FIhu;_NmJ!c#Vy;nr_Tk3-l=im#2$k2*>s06O0TDc?`J`AKtD2
PiZXb*`njxgN@xNAtTk=!

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-1-linear-tRNS.png b/extern/libpng/contrib/testpngs/palette-1-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..9b0133dc9f55261e271d8a4fc5f1dde99b272bc8
GIT binary patch
literal 342
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y$P6UUy?J{QNU@|l`Z_W&wk<GxF)bd*S4j2<
z@?~JCQe$9fXklRZ1r%y{!N5>zz`*b-fq}tl1_Oh5!JJ)zHb4os0G|-o{|pTO|NnQC
zH4y}gFqQ=Q1v5B2yO9Ru=#;odlsM-XR2F5XXOu9kR4_6yG}ZwUrV3v98F>oMrFnUo
zdFdI6xe8AC<vFQEwI#*>fci=@Ln2CiGLuvDih<G$j0~xH3=ACCb$fjIniT|E*MEA%
zD6>0vdWB%ibT1{I#*N(m>p5fV?X{D+?nxwa-R`W)bLZ-qRjaikr=a)VrT&6ho2T`)
zZ!SqH$~%}Hw~W7R^R4?z58t;fJa=oKQD3r#`0P`cPw*NWX*J!Lu@>lU1};w*#}JO|
c$tM^Y81fi$BR;%c0TgBMboFyt=akR{0F%mb>;M1&

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-1-linear.png b/extern/libpng/contrib/testpngs/palette-1-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..bf232fd33cf07bbb08474c875067fb4497539830
GIT binary patch
literal 329
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y$P6UUy?J{QNU@|l`Z_W&wk<GxF)bd*S4j2<
z@?~JCQe$9fXklRZ1r%y{!N5>zz`*b-fq}tl1_Oh5!JJ)zHb4os0G|-o{|pTO|NnQC
zH4y}g=#;odlsM-XR2F5XXOu9kR4_6yG}ZwUrV3v98F>oMrFnUodFdI6xe8AC<vFQE
zwI#*>fci=@Ln2CiGLuvDih<G$j0~xH3=ACCb$fjIniT|E*MEA%D6>0vdWB%ibT1{I
z#*N(m>p5fV?X{D+?nxwa-R`W)bLZ-qRjaikr=a)VrT&6ho2T`)Z!SqH$~%}Hw~W7R
z^R4?z58t;fJa=oKQD3r#`0P`cPw*NWX*J!Lu@>l41};w*#}JO|$tM^Y81fi$BR;%c
Q0TgBMboFyt=akR{0OeS2AOHXW

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-1-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/palette-1-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..1c6f262b336f2e797050c858469769bc7417361d
GIT binary patch
literal 295
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y$P6UUy?J{Q#3>GPcVad_?i&o`um$*pxc+Bg
z`2YXEqpXP_NV+7*FPOpM*^M+HN2kO!qQp7Bpt2}4J)?wSrGk-xp|K8-Fjer%&&X47
zF3ro!%uCNm%vEs8FV9IWsx2x02h>-R84^+AlbM{FR}7S9U}Q+mV_@L8uG{0w*Q_AW
zy8hE6Mw#8Y(<=m9rh6&zG;ZYfU(Xp^Z?B!qbx$IZ>vm^Vo;z2^tXi!VIR(A<F7+48
z+B~hVeRD}tQQpDqxMlohn{VA$dicI=;kjG;jQWx_#Alzne1g~5NUQ0_jJ0Y&`?)+_
g978y+C!b(sV8~<0jrj0(1yGd1)78&qol`;+00^ID(f|Me

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-1-sRGB.png b/extern/libpng/contrib/testpngs/palette-1-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..fbadc097fff199cc4de801210542c2ed3f930c19
GIT binary patch
literal 282
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y$P6UUy?J{Q#3>GPcVad_?i&o`um$*pxc+Bg
z`2YXEqpXP_P(-K1HKN2hzo4=xGd-h(VWonRfuXSukT6y7%FoDCa4yZu%gjs9NX%7m
z$}i7JEvhXk{s+`ok{J?F;**)2npX^zW?*DU&0}ETxUSpd%h#+R(7OK9BSx9sxzj5I
zTc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On$E;ed6*&dH_b&Ap%-TGyuYGe#Qc>Q)
z?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy*hs7C#*DRUK>N8oT^vI=t|y;hWMIf+
V$c^~$b_GzB!PC{xWt~$(69D&rVg>*J

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-1-tRNS.png b/extern/libpng/contrib/testpngs/palette-1-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..8f1642b7b01c30ced4d2aef6cf0823d80e79e8ef
GIT binary patch
literal 282
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y$P6UUy?J{QNU;U@gt-1^VEF(4zoV>)AV|6-
z$S;_|;n|HeAV;UfHKN2hzo4=xGd-h(VWonRfuXSukT6y7%FoDCa4yZu%gjs9NX%7m
z$}i7JEvhXk{s+`ok{J?F;**)2npX^zW?*DU&0}ETxUSpd%h#+R(7OK9BSx9sxzj5I
zTc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On$E;ed6*&dH_b&Ap%-TGyuYGe#Qc>Q)
z?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy*hs7C#*DRUK>N8oT^vI=t|y;hWMIf+
V$c^~$b_GzB!PC{xWt~$(69CLpV&VV*

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-1.png b/extern/libpng/contrib/testpngs/palette-1.png
new file mode 100644
index 0000000000000000000000000000000000000000..a27d1362a2b59c6f76ed0188be16f8eff02e3ca6
GIT binary patch
literal 269
zcmeAS@N?(olHy`uVBq!ia0vp^OhC-Y$P6UUy?J{QNU;U@gt-1^VEF(4zoV>)AW%f7
z#5JPCIlrK?C^J2ygkhzEk%6JH4v;Wa@XF7~Q*bWL%gfA5&q&NwaLO;wNiC`^DgFo4
zSCSbLQR0)CoSIh*lxARLNX=tl;JB{a<IC5qAke!0(<4Ti-MP~%1Y4$iDe*LJ<n~|B
z8C!3!oy>JlB9ZHMXH}j%SI4Yctra;1z4tEl7tGo`t*?D^Nm5bX!R)wY{AHVO-B)_}
zzHQ;TTl<Xqk~PF<pSpa4*Vss_>Bfw;YC!wBJY5_^IIbt3U}Rv(W5|v8@OA}Il)=;0
K&t;ucLK6Vta$gnz

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-2-1.8-tRNS.png b/extern/libpng/contrib/testpngs/palette-2-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..9d2ab16564ab7c7bbdc84d1b8907946bc4912751
GIT binary patch
literal 350
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c2#0(@`f}Y2L1kxRS9T^xIOE*v6*8$`!Bzpw;
zGB8xBF)%c=FfjZA3N^f7U???UV0e|lz+g3lfkC`r&aOZkpaf5VPl)UP|NrCSKo|(b
zs^)P5#hFWj{DS{K+bp-pEg#6$DRGS`an3KOEXqvJC}CKsU}RuutOF!W6}<8@@)Vp)
z^YSwD(lZis6`b<Rb5e_HON##i^_66XM3nesCa2~V1Em=l8B+5Y7&xx$_W1HOD+si%
z|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c-C33A&ebuiR%=C0LGQgw{ROi&
zPwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY*{3d_;59bVYPvCFEztW6T%InD
fAsp9}C$KRv$TG;NRJ~0GiZXb*`njxgN@xNA)(Lca

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-2-1.8.png b/extern/libpng/contrib/testpngs/palette-2-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..cdcf28329b96889057f6c9c10da21423ee4f9203
GIT binary patch
literal 335
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c2#0(@`f}Y2L1kxRS9T^xIOE*v6*8$`!Bzpw;
zGB8xBF)%c=FfjZA3N^f7U???UV0e|lz+g3lfkC`r&aOZkpaf5VPl)UP|NrCSKo|(b
zs^)P5#dS(tBTAg}3o45;(=$pKRw@`77#iyU2~!2H{ER#W=hD2q%)IoB#9RfZ{PLXC
zqS}(;e?WaDnIRD+KAFj>dBs3!21bU|JO&1i>$*L@e9a01t?NHMVwBmPJH0}%WxAIV
zPvb^z|Mi@)_4eAyT=ygrxo&q><+*cp%&OH|kyFrn?^1uktj*K<+BcUZ73Cewj$6iG
zw)xh5rHAj^7M{Dc&!{h1LwxqB%O`k^jkKC>%vcNbF9VmSi(?4K_2da`3=FaiGAdPX
QlYycPp00i_>zopr08LtN0{{R3

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-2-linear-tRNS.png b/extern/libpng/contrib/testpngs/palette-2-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..d346d40071c738076bd4864327c3be3bb087da7b
GIT binary patch
literal 350
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c2#0(@`f}Y2L1kxRS9T^zg78t&m77yerBzpw;
zGB8xBF)%c=FfjZA3N^f7U???UV0e|lz+g3lfkC`r&aOZkpaf5VPl)UP|Nkv4Ko|)A
zOo{pq6lX38@(cd|Y_r@Vw|pR1r^Gd)#5up9vM4h>ql96lf{}rtu?~<hRq)Es$Ww4G
z&CAQoOV3EmRdC8L&q*z+Eh+v7)K`)j5>eulnVgze43uVIWJt|pVBol}+vCgEtRT?3
z{?j8ynccb5D+F7ndnxfWZshh~&ly{9ubs?wPa=`)c4t+dJ6Ff7TCEj11-<t!^%u<A
zJgu*Nb4gNB-ofm+W&CBEZ{1gV_`Yr7xm){;`jR!oXP>%!g4ftctLes!wLtGPaCy2o
fhHzX@p1{VyAj=@5QuQ_&D9YgJ>gTe~DWM4fpjmZH

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-2-linear.png b/extern/libpng/contrib/testpngs/palette-2-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..5c2f6d335dfb5ce156a6541631014175b0e2506f
GIT binary patch
literal 335
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c2#0(@`f}Y2L1kxRS9T^zg78t&m77yerBzpw;
zGB8xBF)%c=FfjZA3N^f7U???UV0e|lz+g3lfkC`r&aOZkpaf5VPl)UP|Nkv4Ko|)A
zOo{pq6xS(njVN)>FQ_caOwTA`SgBxSU}&rZBuo{&@-y-joJ;faGV{_i5_1)t^2>8l
zi)u@X{{i)tWQIhP_+%!h<`n~_85kK-^B5R7uIu*r@--_6w66d3h*4&D?(_=5mg!zf
zJdGQ<{nvBG*4t|*bKR3j<htEimFLdYF{@T<MNUEQy-WQCvo=rbYu{XwRFroxJ8l_&
z+2&jKl^(utTX^o)KBK;54e{BhE}!5vHqvUkF=H*zzYJWSE{-7_*OMo(F)+w7$f#7k
RO$LfGc)I$ztaD0e0ssqKZ`A+*

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-2-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/palette-2-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..e5a491a7139b9db671d71c463f8acacf8c5175dc
GIT binary patch
literal 303
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c2#0(@`f}Y2LIK@HkPR!=VeS?7<o&cW^*Z=?j
zH#C4S5L{T8kOmZIE(!7r{{L*V+#<JpAXlfvHKN2hzo4=xGd-h(VWonRfuXSukT6y7
z%FoDCa4yZu%gjs9NX%7m$}i7JEvhXk{s+`ok{J?F;**)2npX^zW?*DU&0}ETxUSpd
z%h#+R(7OK9BSx9sxzj5ITc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On$E;ed6*&dH
z_b&Ap%-TGyuYGe#Qc>Q)?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy*hs7C#*DRU
lK>N8oT^vI=t|w1mV_=YFkWs06n+z0X@O1TaS?83{1OPHiYJdO$

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-2-sRGB.png b/extern/libpng/contrib/testpngs/palette-2-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..a3bf9a2f3b0e5c39cec1140880877246e0a78fc5
GIT binary patch
literal 288
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c2#0(@`f}Y2LIK@HkPR!=VeS?7<o&cW^*Z=?j
zH#C4S5L{T8kOmajDRGS`an3KOEXqvJC}CKsU}RuutOF!W6}<8@@)Vp)^YSwD(lZis
z6`b<Rb5e_HON##i^_66XM3nesCa2~V1Em=l8B+5Y7&xx$_W1HOD+si%|MZAaW_RxN
z3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6j
zcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY*{3d_;59bVYPvCFts2mNE>9Q75RU7~6WACS
XWEo^ss@^68MHxI@{an^LB{Ts5KSE^*

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-2-tRNS.png b/extern/libpng/contrib/testpngs/palette-2-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..c34a6986d008247f312c147f0f368941cdc4fdc7
GIT binary patch
literal 290
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c2#0(@`f}Y0#DV_kI5ZC|z|2H&%Fc4f=n2-h(
zXD$iy3;zFXv)m%Ld>~h+#5JPCIlrK?C^J2ygkhzEk%6JH4v;Wa@XF7~Q*bWL%gfA5
z&q&NwaLO;wNiC`^DgFo4SCSbLQR0)CoSIh*lxARLNX=tl;JB{a<IC5qAke!0(<4Ti
z-MP~%1Y4$iDe*LJ<n~|B8C!3!oy>JlB9ZHMXH}j%SI4Yctra;1z4tEl7tGo`t*?D^
zNm5bX!R)wY{AHVO-B)_}zHQ;TTl<Xqk~PF<pSpa4*Vss_>Bfw;YC!wBJY5_^IIbs8
aU}IpAWsp&+dYcRsW$<+Mb6Mw<&;$VQsb`P?

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-2.png b/extern/libpng/contrib/testpngs/palette-2.png
new file mode 100644
index 0000000000000000000000000000000000000000..eaf4536e09bed285c717cf5babbee81b156b7d78
GIT binary patch
literal 275
zcmeAS@N?(olHy`uVBq!ia0vp^EI`c2#0(@`f}Y0#DV_kI5ZC|z|2H&%Fc4f=n2-h(
z*C}z0C~?j&s4U7%&nRJ7sbFMaXsiPyOclKHGx8LiOY`zF^U^aCa}}KO%X3nTYD<d$
z0riz+hD4P3WG1KP6$7Oi7#ULY7#KLN>-PBaH7f|TuK)CiQD%4U^a{b2>0U}ajT^cB
z*K@|!+iNFt-IGY<y4_io=g!qJt5$18PC@UzOZ^42Hc#to-&~SZly@*YZW({s=3Dob
z9=>l|c<$CdqrPMf@!6*?pWrn%(rUUfW33v{elAZJ#}JO|$rIQZ7-Sh_RI1)414S7;
MUHx3vIVCg!04Tp=82|tP

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-4-1.8-tRNS.png b/extern/libpng/contrib/testpngs/palette-4-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..20cb465cece78b066cfdb2a5c972b870bdabf3f6
GIT binary patch
literal 400
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j!VDx;!;N!*6id3JuOkB^W9jC}`#OMpg=CK)
zUj~LMH3o);76yi2K%s^g3=E|P3=FRl7#OT(FffQ0%-I!a1C%fb@CkAK|NsAr760Sn
z{wpbgSSuP=#Ko;pvI7YLSwNr!mRn&5q?ME!m6Vbhp8@sqmjw9*|Nr#t=FO8kS8kr)
zQ`u9NFz?wfZlIJ-iEBiObACZ(QD%BZ3ByVSBLhQY9Ux(<;FX_|r{G+gmzSBBo{^ZV
z;FMpUlUh_;Qv467uOu@hqQoaNIW?~sD9ymgkebK9z;Ru-$Cs~JL7;X0r$>x3yK|>k
z2)0c3QsQac$nC$LGq&DdJDKaAL?YMi&Z<0ju8vu?S}Sr2dhcE8FPOD?T3`F-lBA-%
zgV}M*_{%omy07%`ecQrwxAqzJC2NS!K6Uv7ud$I<(~TKxfx*SV<LTlU!f`!0C8UXg
Yf%y`{$CEi7=Yir3p00i_>zopr00W|r^#A|>

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-4-1.8.png b/extern/libpng/contrib/testpngs/palette-4-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..c2318ff82ed838af1bbb7bae3422588947958c9b
GIT binary patch
literal 373
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j!VDx;!;N!*6id3JuOkB^W9jC}`#OMpg=CK)
zUj~LMH3o);76yi2K%s^g3=E|P3=FRl7#OT(FffQ0%-I!a1C%fb@CkAK|NsAr760Sn
z{wpbgSSuP=#Ko;pvI7YLSwNr!mRn&5q?ME!m6Vbhp8@sil(<HeIOi8s7G<VqlrXGR
zFfuSS)&UZx3SRjcc?!;@d3l+6=^2T+3QqauIjKdpCB^@M`bsiGB1(KRlT-7Gfzk|&
z45@hx3>?>Wdwltt6$Dz>e|p3yvpaWsg<#8cFD0JFjokk0Ib-YXwUfE-NhEUJ?ySml
z=jxbMtF<Dhp!eRT{(@PXr}edOE=elNJD44}jK6I2t@}z3-?uG1cWa+fU$Tby>{FLd
x@ERLwHQku878oWBJf1F&Asp9}Q$m^;7?>|Hd_0-caULkn;OXk;vd$@?2>>5Lfr$VB

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-4-linear-tRNS.png b/extern/libpng/contrib/testpngs/palette-4-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..4d96a47241327d17d0c749411ec888d23a267554
GIT binary patch
literal 400
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j!VDx;!;N!*6id3JuOkCv+XBNE)8c`Ag=CK)
zUj~LMH3o);76yi2K%s^g3=E|P3=FRl7#OT(FffQ0%-I!a1C%fb@CkAK|Nnn``+p0I
z|2#Y(R(n*tg+)7$97qVr0s<beT)P~Q=HZFr5lX-D6R4NJB*-uL|EFg+Z=T$_a`XJ2
z%AT@>dCz`v1Eq9ITq8=H^9w4AGSf3k7*;A685kPt00~nCul$TW1?SSdyv)4xjKo|8
zr~LAq)S}vw;(tJWC7B@+B|e$Ssd>dfX$D4y)I0_Tj_bNTzI@FJ0<G&mJz|vEojbik
zuw}ZJ5>MksZvXY1vGw-a$z1m&61i@7R^_>Kb<C>OT9H%Gd+$<z!K}^G`r0>_Bo*Zy
z%#K^eU$*(yeWi!*+ZLX?wa=(8SwnpGsmmvLjg7RLZp>H<3@!#9PZ!4!j_b)OAx#Vn
Y%$FEGp3Lbu4-{wcboFyt=akR{0N?727XSbN

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-4-linear.png b/extern/libpng/contrib/testpngs/palette-4-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..dfc5a868ee2413ffd6e34fa8d2e389db674af3a7
GIT binary patch
literal 373
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j!VDx;!;N!*6id3JuOkCv+XBNE)8c`Ag=CK)
zUj~LMH3o);76yi2K%s^g3=E|P3=FRl7#OT(FffQ0%-I!a1C%fb@CkAK|Nnn``+p0I
z|2#Y(R(n*tg+)7$97qVr0s<beT)P~Q=HZFr5lX-D6R20G#5JPCIlrK?C^J2ygkhzE
zk%6JH4v;Wa@XF7~Q*bWL%gfA5&q&NwaLO;wNiC`^DgFo4SCSbLQR0)CoSIh*lxARL
zNX=tl;JB{a<IC5qAke!0(<4Ti-MP~%1Y4$iDe*LJ<n~|B8C!3!oy>JlB9ZHMXH}j%
zSI4Yctra;1z4tEl7tGo`t*?D^Nm5bX!R)wY{AHVO-B)_}zHQ;TTl<Xqk~PF<pSpa4
w*Vss_>Bfw;z%XIp@pN$v;kcfh64J!Lz<i0}<H?+k^FVP1Pgg&ebxsLQ0AvGws{jB1

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-4-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/palette-4-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..92d23e7ddab4ee1ce549e649de08b5a03fff0976
GIT binary patch
literal 353
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j!VDx;!;N!5oZ=vNCuZ~GzQI6_L4Z$)>;M1%
z_wWDT(D2{E0mRxre}6;6euo5*5Re4~4q&<c2|(JxVZMW$$>cnsUjC9Gzu^C$p5458
za_7p;^Lr|L$`a;1`^62E(kXF`C~?j&s4U7%&nRJ7sbFMaXsiPyOclKHGx8LiOY`zF
z^U^aCa}}KO%X3nTYD<d$0riz+hD4P3WG1KP6$7Oi7#UK57I9qH?eXPnRuE`i|LGB<
z%<kOj6@o3(y_9$wH*)*0=Zvkl*G}fTCy~f?yR$0KovUM3t=5X1g5G<V`U_@lp4QjC
zxg@D5?_hS^GXAp7x9%%FeBZY4+^u~^eaRZ)vrk<<!E0=!)pTRVS~Z~kJf1F&Asp9}
dQ$m^;7?>|Hd_0-caULkn;OXk;vd$@?2>>lMh=c$D

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-4-sRGB.png b/extern/libpng/contrib/testpngs/palette-4-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..26ea9e5ab1490f215d2039b6ba673694ffbcaac2
GIT binary patch
literal 326
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j!VDx;!;N!5oZ=vNCuZ~GzQI6_L4Z$)>;M1%
z_wWDT(D2{E0mRxre}6;6euo5*5Re4~4q&<c2|(JxVZMW$$>cnsUY!!xh!W@gg36-I
z^o$aQl?p}%hQ>NT!c@U4KO;}Uxil{?GcP?OF;~GUzdR?ksJ5i|A5dROW=KSdPiAsz
zUNKObfsr8<Xd1_L-5y`QW(9%P^`9Ow%IwaaULn{r-Ajq5aU-|?dd}E-d+lVddlHFU
zw>zuy+_^et)oQKCDd@d-slQ;>=4pNHn@f_4@(yOlE#oiSeCxi_!}o0q&)wQ*)R(Lw
zKKs<=6THSoT1_`*tW^Wr&*SOh7{YNqIVGftfr0rF!^e|39p{1K44$rjF6*2Ung9{c
BdKdrz

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-4-tRNS.png b/extern/libpng/contrib/testpngs/palette-4-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..429f6b95394f3cefa274d8235a861b8f6b8ece3c
GIT binary patch
literal 340
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j!VDx;!;N!*ltF+`i0l9V|M&0z-_Y>i!2!hD
zKYxEi!+wVZkPwgs1P)-i{Ru$Y!C}6GoXO-opkDrxAiv=MpPt>kd2;8<&GUOId&&~#
zJ^RHCl+r12jVN)>FQ_caOwTA`SgBxSU}&rZBuo{&@-y-joJ;faGV{_i5_1)t^2>8l
zi)u@X{{i)tWQIhP_+%!h<`n~_85kK-ffjLG*X{A;YgQ0wUH|D3qs;Ey=@o)4)4h~<
z8aHzLujh=dx7SYQx+jsyb-S}F&z-AdR;|{GoPyqam--84ZJyTGzPTi+DDPl)+%o>M
z&A09=J$&D`@Z7C^Mt#W|;<Ha(KEZ2jq}6m|##%L?{XCv7jv*Y^lT$*P7#Nr@F?>9k
S({Uas&fw|l=d#Wzp$PzE{e_eO

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-4.png b/extern/libpng/contrib/testpngs/palette-4.png
new file mode 100644
index 0000000000000000000000000000000000000000..82f3489940e4916a1a78a74bc85ccc370b9d33fa
GIT binary patch
literal 313
zcmeAS@N?(olHy`uVBq!ia0vp^0zk~j!VDx;!;N!*ltF+`i0l9V|M&0z-_Y>i!2!hD
zKYxEi!+wVZkPwgs1P)-i{Ru$Y!C}6GoXO-opkAF4*N775{DR7&%=C;BhLs9N28PBu
zK*ChPD?cMo!MQXqFEcMaBQaOODZe}?wWzkF_#aSTNoGhyiBD#7YF;r=nt_oa6=)jA
zb=@9czGel1*7ctrG0N=Don9f>GTlpwr*R{<|9Z~YdVB3;u6q)RT(>)`^4z&PX4Pt~
z$SLT(cd5T%*5+w_?VC%Iit-L-$1US8+kET3(!=*{3(wu!XVjOhAwK)m<rBQdMp{ib
qW~@~M+Rx+Z;uyklJvk+$iGhLn62r%nIUVPL;tZayelF{r5}E*)=XWRo

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-8-1.8-tRNS.png b/extern/libpng/contrib/testpngs/palette-8-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..c10bb56973957489e019a3bd11a4f50318d59c9f
GIT binary patch
literal 1360
zcmW-he{2**6vwCH8Z3-Ik|u+uDa|A_@<Rqnnrfp%DZRi^hI0K8ngUDfdG=b`;cO31
zu&td!Db#`xhJpoaNd2*3ph6WD2V#pNsE7^%0tNz!W)u<<qJL<N>umRr+5PN$`|{rR
zy?tAkE?EH6pG*e;!0^K2G62%-BS;%R&Yll-cZBTi!Mb^D9!N`DJG|@E7R%Yug=GwY
z4LJaGYy#jP`>MkLuyz&zf7Ad_uonQ7*ncAO9023M(!~`a-}jC2wf2?rJ<pfY7sBV<
zcU_+`pHiO?A7dXOA41=80&jE4=uxAFj5lCpuMw?=HyYP9tklpVL-GusYEYJe8OE6q
zgf^pEAJb}3ds53TEmE2{XxG&&qG?Ez0*#4AIT~haCnLzi3@JURRG;#Clx$a`Me(?D
zUB${34J%TpaK1t_70gjiR*<wA@U-+)kLL+braZwt9`jt+W0f9d9tnAvdMMw6#B-(w
z6`EeDyQFHDUP{V@6b+I`rRz#oC22&G5{W|+6-rnjoxDH}(<*dIs21UIAsd8<30^B)
zSFmb9D+P%N%mfMx7!poVpq**tx`C@W_hMW|xv1rQ6?a|ER&ZL)NfpPH9F=nz;ZA8F
zwAIeaVJoyr+dOP&>uoRQy3}=v>tfeMt_xk)8S9EEWjexCIrA!+tYV^?@fFsWu~m%L
zG7@Dt#!#HW2Ie#dEi^?`ho}luk5L(+qLT7z8<?_MN@J8XP|PW6p)f_A)}Y@ekLUuT
z3W*mYvV@2T;Z-&Z!lHyW5RxD`MNm6|UBu}PhQmz7nqZZWJ&I)r3x;{6O&PNorW}(L
z#sZ@r3?+63f=M!2Nar9m6M6Ya79tTwyxi7@SRBz7MA{MVL8uSGLF5btV`nm;&V(ul
zdIZV>C_<1&tQe3rK$?Q23t|b;AcV)DGaAgOnc(OQM`bzQR7d7HqR8Q;Ryl_?I<(ax
zy$&95(2xU19p{qsK<G}f{Ym^}*^+Yq-@pI5fA8+^zumt1%hk*Jf`vQg*IPHPUHR#U
z^XJZ-zB>k&FJAcW?3W`aPaMB}^ZJ!B_(Fa5@zKMFu3q}_{JF12P6lxB-2-o3`1b45
zr%oI{cI1$SH+SziGjj6Nk3Rh1{lS6$-8;8!*`z)h4ov&^?AqSb)zO+7K63D#xA*n!
z?CsvzzCM{)ZK;3vj@LJf)>Ly-JnD{7SI4XCUT%D;cEz%?K5Mg-SRJcbUb(a+)Y~mu
z$EdoZG+a!d-Po40o;3l@fBu==8S7h`>S~u)29!U0`jp9u`sm7Kk&<F+ZBr&cF*kpg
zYo(Zx3{@rPuSu+LuCI$H!NKg@S+nQNut#3@qBU`zJ%26d^}H@#+mv0jCe;{gZcDcO
zXTM9<S5zez*GFT##hUG|ig5tOUwOKhJ+d+Tv96)}x6?8|Z`$+9<D2#@!V|^O38h01
zuY7Ip^l18xNww+Mw{GAI(zo=tP4gNP+ivJL68*z{+q;L8FEsO!)$V(bt{c8~6W_YG
z`M~$rPUUWoK85yubMY*klRK^R=e>vRx&sr##q%mAU5vh%c?*Ef&a?++xBY3?9RT6b
LlHwypHJ$$h>0Uyi

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-8-1.8.png b/extern/libpng/contrib/testpngs/palette-8-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..cc09ee60f1e7c375ded9e848697ac5e746d1afbd
GIT binary patch
literal 1093
zcmW+#O=z4&7@ln%shf^J5SSt%EOQ8^)=rxe0zt-Pn~!$ePSb6&u!K78x-QwQ+sTsM
zxLT5!iCx=<SPu?qsS=QYj0at8ZtYMoC-LB6N>M6Q>S@q}Af7z<IiGWw-*;Y~_j#Y^
z#<{a6Q2OOG008AqPMilI6}BL?Z*Q2Ny|x;K<(b)WJ`Pf;#hp(dTo30=`Q&*Hz?A_2
zR<8o^Pq<q304yE>;P*=ajNS$SH$K0Ye;t6m;M|$%D2`+AW9MRPV`E~iW2Is#V<BSB
zW5!}iV?tt#V}xP|lW70QyIpU)-fVfj;nk9tbuWbHlb&Tg9rk3<<9?5NJ?u$R`(5Ym
zI=k(RcDmzK+sT>}!tuOgk)xxIP=^N`>T|F+!Qs2sZCkr(&AQbqRyD1xS|Kc-vMgum
zm?a|?AGT<~!u|xb-!e`cyKam!x^0v+vSNfVykHnNG%|!4JYo<va4@ORZ)n%ic14@E
z)(x#{T9&mCnin<8YkFFfNaHb$Ml~Ex=<rL*wUuouBbBZxRZ+5}giw4&v4Wy`MYzH_
zg(3yB33t9OT}|4mG!?1KQkA5<D20&xf@Cw279}Z2JS9<H!pVf_z+IptR2V=993gdx
z4ucE9grGtYA+Qig2>5?j{3LgIZl|~@a9!kThRX{fmh+38l{hVPQsKDDQH{fT(n6nQ
zE@C#v3}-seRDsEvkeKljV--egj7Wx?47C|tO8V`GsT-wsjGBn*(^TcDECv*mmno}J
z+MuLO@d`y93O5pQ_(9?*u_MGVq9dX>k%a)6@Csp)&^958;B|sDfm?}^d_Q&r*dE4a
z1nV)Za#&7<`Y^9z*2HuLlXZ+YG1|tko5;@hBG-rP05TNmQKTXy^MMS+YlyWG?I5BN
z-bUyyg1d=EeGhcK(Dp+!2=y>jStut1bCA~|TY_{0k}Zh45bZ+v2=0mgm<T30)QXC&
z<MWO87v^TGE$~%l=*ZDyhr%?RIW=FEnd6I6&dJ$o>2fAJ->z2{mRrq#!@t(tbg^}2
zu3VAL@Ei<UkpS%b>9r01{D+wrJKev2OZDBqeCxfJuHHID_N#AuCcDqQ`N12nmeWrT
zl+wT4xFS!auisfdXzGoRpSVvNcXl>!UfXHCwIIKHM|}ChyE~76B~SnS=!+j8KNz}M
zeg%K_!^7{<v7v)&Ki~d3cpU7{O^i<;cvybB?<oLlYpFd)m;VkP2Ot-no%kkuY3)Br
C;i|6y

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-8-linear-tRNS.png b/extern/libpng/contrib/testpngs/palette-8-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..27f5a3336cffd32e8d290509aa4c6ababd82c32b
GIT binary patch
literal 1360
zcmW-he^6CL6vubnxTCL?XxtejoD0Yp&f*(<NP3O%4L;tiApUp+BeSMJKo3S?37?W8
z1^8pN)MQjNv>!YDLK`)stW0-8%d|2}OH;c#I#Xlij5ALCQB&Raa{t(SKlhw_=A7?2
z_iSD`pN$PX6aWB>EuB+R0RS|Q0FFlHv}AYG-0q7P&npIS<7=VY{WXR&>*rL=17OX=
z0CcYh;BWJ)`!)b8rvmU>EdY=10U)()-?7+Z03fiiyfW%}p6hyAdrEmydO~=ddyILG
z<5B9_wnvDEv1eHxLLP*^w|mmngRbgxWv46RF0XP~)O8$}=DK#4OHy5&;#vV0CAn~v
zAKD$%dZ$)BS_&;{G>>T((T<~OP}|v>q-#vHm8{Vi4U_yl+&-mylxkP9L5XU`%M~kD
zj-zOvvU3#4P&iFl;}l9(FyJTcc1kUzYLJpk5tE!r7M6}9X-L{sl5B}>X{AX-Buw!u
zbmKzT2vsd)Oo%eUBZ3tP#}PDN*g-)i3!E*i41v-GO!eh(tGJGFRn8^jBEor?vqJ7T
zoEC69#7U52%B>uZvN_E1wR59PN0=&RGR#B~<AsdPWRAn=bY>SYlFx96S$PZv8O-&C
zHrg3EOob+ClZOdyyv;=&$95dzIM{J4$3cz*N4nzXQXQl!kIE1g`IHw>Hr@DAI+NOk
zloU}MrdBaU5elPz3*9VRXWJ^rmedwOn}=*xU;^8;(6+-iiP)IgR=JI0Hmvgd?WPi)
zPE-bw*+fhxJV;o+$%4=#Vn+xmBREE^YJzGAjQhjkreIC5O2g8|A{%pxS;(Y}X&BoK
zlNiPvTMZZq3_JZvas!r5w$wOFrdcAx;yD(}Gxb@t*s{wlQf=V|%WAh!j|Kbuv2&A<
z9)naek_3r##Iq3#8Zi)!AUlRg4Z;FhJqYbYaL}JocNEk~Pz9h&fg%<1EXZ<=a*#%$
zT?I)T;!bGwK{N>ANtiNg(ZA*=@e&pDANT(G>(6_4@BI49ts6gGxpd*Yf!}ZceDnI%
z%in){?(FGPcShjS#q(dE`E2;av7@(cT)R91pC14CgChqIT>0U<b7wyvKH<auH`UAM
zzxv{oK6doILkA4Jv}^n6;S(Rd|L!|)zy8X=uD-3C)*t_H$T#iVy<^++8@kta3?174
z#;be#`?kn+&#q3iEi*K*Yx@fud)9Wew=~r+9ia`~ovWT+{#4x)iz@n!%~0F2#@fYI
z3+G0+$ey($#48t+mdu*DuB*d%*7_7Fa`LCFUeOY-TU_PSj8N{RjJD?bC5vKnOJ*6{
zq>Qxij2%mj6jKt>>O@4et!{6QHzmOS%>1dLX;aMcNM@O6YR!zSY;A3BjW^Y`WX={H
z%NyIf5-a{Q-zAzWs}tqT^^L77jM?m}##R7EUk+}Wm%J`BWy9fnx8Q_NT6RD4;QHNV
z6LHUx`xhJ@v*fvOZhheT_`1Ng&1+g&VADVs9bDeF_4<Vu+XjaEx5=TzlkKg;%a*?N
zz^b9EHzwY^yHR~}Rp)Q3pPah)%Zq2mPRpmgKkhkb)*Zm5CB>EFFV;6qxCuaSFB}!>
S`opX{07|3tOAgJh?foBkCGgw;

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-8-linear.png b/extern/libpng/contrib/testpngs/palette-8-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..40d413cd660350acbc6346e5894d196db7ccc59e
GIT binary patch
literal 1093
zcmW+#O=z4&7@o<Pp;;&EN(Z(vWwPml36n1AZey7m<Ffs-OcOS>TM}FbbX$|K3AQ_7
zyY;6bn8ez#pp`&rOZDJfBp$R#ZVChTBpy82gHoAFJrys4coOt;KIbsM@4P(k^FGhD
z)2C#A>X{S(pnvA%^cetP*aEl@g&CX8YFM6VRpu%HUj4NA_+~SlbBia>%mHxuSpYV#
z0PuIX+I$Sar6U0Reine|Zv&8B`{e8T3jiQ+x;9^p<JkMyx!Bs+m{{vrsaVQbh?w)3
zv6#}BkQn0_p%}s>+TZhT*V`R$*1c|dwcusd3*q^gXTzRmJ;`{S@~GFto+P#3b?%0<
zTh3^wn@-i8jGPdT7aYqwI_L;>IPFlMgS`n3zhm8&wH<4gtZrCUv$A4^uzcLI5le?G
z8L)W2MQICD3247=oHlmJ7-e+bC~0Kb2w`~9Fm7nx5N7azLDaxZQlW2Y*VMM5O<n6*
zts*U_v=Ew?G%IL2s!3ksA&mw#%qDdB1?B3>)|8P-M@p5IoK!+6KA~7q(Sjme;Sq)M
z3JxdS`Kol0v=wQ}Qcp=WDdlk~gyhF0n~=05Nm1f)i3$>qB}51A0v(~k06O3ZsY7%a
zTnHuv6@mzXg+M~U|GVPHxGQiw&P|c)5?2#k9t*LYALne6(<x5M99KAsIIJcu^ux^M
znH^z<GhJY+$mB#w%=jc@Wkw@LB*Qg^>I^O<{q|Yv2B{sQCQtP!RRt<b0R`n#ltq-z
zQc|b5K~a;!Rw53cA&wF|Knx=~PZTGz7$6f~CQK4qCqxmvM35$MJyDWRVVA~sKQ;qc
z4`DTe<#?zM^9p7)OdFUiVcfxJ3&Wj6cD@(6K4jC#P^1Tu$|G3_WFQ_PR!6jnh(>q|
zp&JP9CK~lU(Dg!_f+hoX7OG(=#{zSZS0P(~v<1mJ#5)k}LU<2mUVQnVV3Nb#YNH$J
zwYNK~t(7kLJXbnWJbE}x&*f(IN;?-_YPVP0t(9{Zawqhg=a)Mh-HZQ*f8EvjMz^-Q
zxZJ)No`XS`+W_qQsqn#E`rTaSy}N(@1`mF7;nrJEU%54Vh-`iJ<V$z^UU{cHwwQW&
z;9TmLYnR(H_5Pg=zI%S{!-qe9w039j=5@2zeXY~}_Vrgkd+Lq72frSA^v6~E!vj~k
zzBrow`1||c^&c(q?VoRd5j+ma%yeb`!2QLggO32%-iAHJjlY7&0hp<tn*Q>{+3o)T
D7Ij$p

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-8-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/palette-8-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..b8863ec2b8ffe01421c1fd561ddf880de73af07e
GIT binary patch
literal 1313
zcmW-hZEO`q6ozjlF<3#zU!ox}A;B1^$xvdzCc+4}q2;5DrIbbrnSRM_XfNaK+Lqel
zw543?r3_7l3$1lRs@7s)tW~NMSQ{(_6-TLpfMHS+jYg75i2g7!uCv`AlYRD_J^P+_
z&Q2#OST{HG>C8wZGB-ajS{R9BxZ6m^>{)JoILUKEs4HBzX4Z<yO<N+7SrM|aC^rZK
zYXf5ftpnc=lnSH_ga|kf7z-#32njF_5DFj+00^_~v^7&!PgsA{sv#@;tmv|wTb8i2
z(vo6}^DN4-Fw24kVQD*M%%ss{##crS7@0OAWjHs?Gc;yMslmjcsDUdD$O?7X32nx-
z9@hS#R{dJ`Xwj)T*Q{RC8coVIF43q!!>9&1p=dkm8|CXk-<Q5h`%?HK>2vP0MxQdD
z#C%MBRN_P8gS@aqJEY8j(*4R$E7h%JN{J4|xnfO<dWysqjww{GV5tJdp&hnQnzYnC
z(ic*tq)bZDE;*O1S<*&HJc*e^H4?@os0_WcUBaY<?i7Afs1709g=iI=3${<tW<i<+
zZWO3qKu>@~XteXr+2J~LqMZ&`+GV?oaZWiWoMX-r=a6$Svnw{ijK_36^Bb9JVzQZu
zeJ+==Rz}+y>0mg?P$z>a2D-v6w3XDvsIH+tqspVQk&0$ln6h?Cla!<=78LbRn5LjF
z+;3Y<OexXj#E%gbC(<LL$*CZ$gU}Qq-2|rz>L+l3fT3_WY#ufQ>k{l!tYTO)EE=6;
z%#xT2Owt%jj0Q1O7>tIKWOI;-B3*#|5~RwJtU;pQ^@ms|qCJT8BRq)EFoI(UOoU@+
zv!GcCbrkvps!}LpP<YM^$WoA|AsK*JK{N*8Bm`68jM@djWC5K6{5+tFfvf}~;hY1k
z3(!75h5#M~Xac|~0H(p)neqAV#|XT_f-S+n|NQ;H-v8sbd*+v0H?C_3fBydK^xfMx
zfBgR1)ytRe&%li-{q2>n#xI;Zd(YgtIRjsw|KhXZ)2D9z^ux8Q6XO>`7<&I?zy4<O
z(#3OUKRI*C!HJ_sE{|XM{L_y=8XS1H_h@(5!Tsk)N5arM>7K)Hb@1kfkuyW@$-ZOV
zhm!64_Ihl$qu!%OQU_X_8xpm#ik&mm!QZHVt>)FT(rtyuT+9*MT}8KVB^z=NC0m<k
z=#`?)`O#G`w6`?4Od8VK7guIy?X9cbRknR=NGp~tUA&N0SM1pK@`mUt7hAmWsnsib
zb~-DvyxbCR?H;x_QN1hXMTTHDTDCmPEziUCdt!08_VswYI=(AbRtwkcX{f16w0L#@
zx%a&4q7rXobwyRY&V}9KQx%UyX5W17(5A=QA?Q#K?q$p$t4%jPu|K_j(VW)dM>nfS
zcD%WIX+`GUd1aY*I-BC_G7t8)Ecvj8b=|!#SntTO!^sh^JP{w?z4L>|>ql;zMbq}c
z$?tAo%syQ4?2~<8PhFY2JbOvo&&N+c<Gw#9Kl)P9ys3)H`O}d|TU*9M%Ub?A?w&{T
Ma|@zp*3h>90bVtOvj6}9

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-8-sRGB.png b/extern/libpng/contrib/testpngs/palette-8-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..90f8912043164c8a6cc451a6c74183cea0e6498c
GIT binary patch
literal 1046
zcmW+#&uiR86#vG6)V0y^WRXyY9z^O2(-g7f;+Ss8rnGUWA?zW_bhDw~;P#tg^L1U9
zq)xJ~>#}Z#5^+nHFi60-2OUBVIV?DM2oVnsxCf;|hxiW+h-bgf*Eu}q$9r!+@AE#d
zO%~=RGOuKUAeflX=WYkVnBN9t=f=H#w#8@D!^Z8onen$yZ@m`;;{mz3IGZGibBVQy
zF^SfRQi+s_5DDiAV+o}RAqmC_LJ5Qk0I9b-b9Us+iPOhU4V>&d(RG|VR&liC$dbc(
zho&9OI&d*f?MBv~S~Ij-S+#Fv&x(%a+_Kox(2`|~iA6aJuUU{yakvv>hsGQlePGm{
zk-J8;4d;ec4J{i|G`L{Uf`K^$rc==FSX-sdf!0#1o|Zz3mgZcunx;&XP-Ci5K|`WJ
zKCRFVl-*ZmPwAdg50&gF(Nvr(R#!AuBvLq3sHotw0!t|!t}ks*nq8@dR2?Z>QZyvz
zl5I*_lO&dyNmQ0Fl%SMy=eojnglP-i5~?X=Lx^p`xnTDN-4vuQa8019fUy9TlxWYL
zr^8q1L3<oNwfFXmaZWiWoMX-r=a6&oe^*?E*_fFs(>12*Ol~r9-}^GQ&1i#>Cc`a;
z+6;CW=%y`nC2B)z%2YF|Vk&D?Z2H8MH7IRS(xF&Tv`b-+f_~a>w?ynRF-4+7q9P(=
zBI+ImVNF6igghj;N6;RD`veS9akxCT1e*fZ6sr(RhDFUo#;k>@z@&$<#OMG+g~4&E
zBsYz04w(g{3rH1_EF)3%^&!?qbQh65gbxrpL~w|}Nh&*+h4vaWIj9L#%TR_;#GVYu
zI*|4t*@sv`G=%UJf>EkbcM;euFw;Qifm#Bx1VqI%2Ur)-J|F{tj{!OXa0I{^_$m`k
z`oYM?vxWHjI{T!ub~lWJ0h~ftu4cV?6W&-4BY6FzC|Zl|hIj74ne~s$tCg*I<6j>a
zuPqkhn`<kp(T0Ea6So=#!MWex`0~~Z4G5a*@4v<-hxdB5mp<#=xO9H|@cDPubMJrp
z_UkK|rx)&I{%qHyxy%=jw=REIX5FX13HJEt>j$l)xLApP`tXBqU#uQIv6s%==imJL
z<j1K8E3duW|7G;^#MP<GJAXX-{#F0~`T5*Cix);KrOC4(*x4C-=E~MTkNkZwKf93o
IVTSJf2i)iD!2kdN

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-8-tRNS.png b/extern/libpng/contrib/testpngs/palette-8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..9660e67765d96cc9f0f521d480ecff9529a1a1e0
GIT binary patch
literal 1300
zcmW-hZEO`q6o$8w7_6Y<FVPT~kYEhdWGFFU6Jdqh&;phbOKGH#>6hGw_A*}9w$v7<
zE#*=#WoRl~Xsr`cwH5<otx~1H*kJikag-_u7$zmrXe610=noU)I@|p**=Nt$v+sH5
z>~!LyHM6sy%=SEQc40wmqvvJ0TQ6(o47Wa*V)>po!^7)~^TRN-HZ&&GI#eo@G87`@
zJY+1SG$bU%IQ0Dxp%B6lfGFEeSu<(%gjJ(f4q4G>d6#9((xfF-7MEDRz@j`0b1aw_
zm9~?{TrzshC~4$?5gEhNhA~3}L*fRP86O)IGjO>9Igt)Kq0N}q!&(h$*{?;9=AD``
zP3twO)wn|Yr5Y7!7}Fpx5^YD7kxCCLC6vr4!4*#_#uRN-gen|YK2fMtL99SQ)S(@c
zW<ctGsWMV_OOckmLoz05lO%z}3F*frs*tcuf|AG%+b2v$=pLcCkZB=Og0~CC1Z@_i
zQQ$!MRG?Y`;{sGg-q|j0(p-0PmEy94i+0XiIb)pe;iQ@4Chj+KRL^0+K{7JhdFSkK
z9XioYhb!%}-9;HAjA6!n#t>tWF)+O=Hc3rDbv;#$R5nr3O!*#{OKB@5?G$%VKSfa|
zg=q@9qAj#l#KeiNC5jRm5Yb3@vnxz!J0U58)5PZl^$?gLpfB2QTY^m)))iRAu}okQ
zVBX|ZVA_F68sl#4XE5r=Z~%j$XgF+vZ?LaReMNj3_XYKNqm%5@lux*iGrli;H0VR=
zgVAV`Y#uT(q>GR$MX~~kTEy#Je~5M>(t~h6@&^$bMsN&)iD>L>4m8W5jzNW?EQ2Br
zdEm@|G!01x;sNMOh{hni1i@r9qjnxJIY8$DRRClO5LJLDopXS80n!KX5b#F<ngDPT
zfGO~Hc4DskCBk51(aYh#|NMR5-uvUXyXKdh*RN>@fBydK)SX*5e*FIGm5UedO~ds`
z{q5zi#?PHOeb?N+F%4gy{o=FXlP7Ne^uyIF6XWM17<&JBzy9XZh4W`le{$-CgJXve
zT^v96`KKR$G&t~X@8RyQ{d>=jjzpn%GCc?1>R`<cBd3Pm6MaXz52V`n><;J-N4<v+
zrT4WqHze!gmD{GNgS}DzTJ5XlWt%r1aWO}9M>W~939rjPkZNt7rdNtL6vkFO*WS|L
zGD$?MpI@GvvwK(F_VO*8B3ia&@xuAErgH1%m)6BrxY)w^Ppn+lv&~tN6Xcf$t9R1f
z$(rr)z#D?OXvxwXw>%5i?u;kk>emyAn#A^ac^zD}v!S*+*%Ivf&%GDa6qg3;YbvV~
zyIk0vH`NKxn|b4z11~<(4nc>!e>ZFHSY4*^vAvnK3ud(rKfFOcwDrxEiz~D5%qh>l
z-Px2_lfA#UWzmPVwCm0_PJ2g=988S_70JZ-j%^=2T0e5jESR$Uj(>OSeD1-@ryuY8
zdh+t@rMZjRem;8gDfj(Zg|Qck=S)^s&7JbRwzjMXmbCnJ)IIkK^NV7qR*|;<0gfDi
A!vFvP

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/palette-8.png b/extern/libpng/contrib/testpngs/palette-8.png
new file mode 100644
index 0000000000000000000000000000000000000000..2502d305b57df2ce24deb63bae3c39a1d9629fc7
GIT binary patch
literal 1033
zcmW+#!E0Pa7=N)Kb!~J!StOL92a&qMG({-6IBhp{Q)(O}ggr!=ZZ`CVZeND&>vmm|
zI?1}O%eoy(#8<k6K?24-=n!(qVZp&esCaO|J+xHl5dVPz@$7S+bNCo$zWL4X`+dK!
zOXjam=HAK$K`=R2EPNaU6Mh>^oIK&<%N;%&1SbM=ePK3DQ|D4^Q)5!CQ>9WVQz25$
zQ^rzCQ$kXVQ-o3oQvkATckJxgnIoqUof<khaH8)xcdX`U#gRpaiw?~=n0Mez2JOby
zKCxzGwX$m0%EXGE<=nE^($JD6i-|=A3olxb&v>{aV@Jm98@*@Lj*;6&bPeZ*)eWs0
zQZ~3`(7b^K17<SP?oeB$&7Rg$t3*qoMMrb4SwmB%NvJW^sH7p$pqN$YhRW_Lv!isP
z)I%kEO0*T{iZvCD6^RrM6)G#Zq`+b(hZ{(nNV6@qkg6wTM~ar@T(WgZ8<NBlGl{Aa
zh7wdV?Ob2jo-kdZJ3_UEYzeU`I2Y``pzDG(1#Spb7cdr}mI>{(^K$qKJ!#LwL;GyM
z80VC8!a3#~aSk~L|98dJn2njKGu>dS$>cf{_kAv7n~b&?X*1kmsLNoFfqvFPSD`kf
zrb;!VDyFhQ#kvQktVL;uk{-o^qHPKj3I<uf-6F9|#FU8+iHeAfiD-HjgtZCn5%Q4W
zgrFS)cL^9~=5R%92{t9HDOMqt42y=Rj9CX$fk}d~#Apvgg~4IwBsYU>0hxKEOGuTG
ztRhkO^&!?pbQ_T!g!d5IM{tC|QD!@rhxQ^g1*i#BOHhVT#9j=@dXOfN>_V&{8bSC3
zf^p_icLvxzFf%|Gfm#Hz0z}O#2Us7_0U$$w4*@y?a16jP_$C)k`H{%Sv!(dT8vCra
zdNYiJA)H3%FXVlAA6{DvBY5R*6s<-#!yC8Z<+Xd&mD)yp=U@LWUR@}~*H@QUqC5WD
z57|l-1Sg-q_w|RbwIFD#zyF$;8r@DBZ+wwlJ9}z#|J9GwE1!J+!Mn@37pHIJ{_HlR
ztGTZpZ=Cy~%K9(<5bW{6w+}i8ak&=#a_iIYU#}lLw`Y&tm*4&V{O9Qh%kR87_-*{_
w<b~;TThAW-__qK5)Lh}x!s+pHW$HKxwzei-I=}JHBYz&u&CVBox=gqJ107oE(EtDd

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-16-1.8-tRNS.png b/extern/libpng/contrib/testpngs/rgb-16-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..03251b12ef08a06018bc3a411f6f02265ba3e14e
GIT binary patch
literal 1211
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583dSsRCB}QA|S<*?&#~tz{ps-dGfvvAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn=geV#6kAr-gYUfs@kz=4O^(2MW=hX4ES9b9{WiFw0LuSrYJ
zoXNSdYg_VNeb1s<bMKvht?20&%-|8k;4z8GVUh^Lq$La!R9G8SG#OMp85KOa7(B_4
zVk}@GQzth2SP!sL<{WfGso_P0nM@Bjs1<GyL&*qmgljNjkh*aJOcoTS40MMsVX$bT
vIJu!1iV*-PvLr@*5QB^(`T63{OZH%uk898Ey)zeBGB9|$`njxgN@xNAtJFa=

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-16-1.8.png b/extern/libpng/contrib/testpngs/rgb-16-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..03251b12ef08a06018bc3a411f6f02265ba3e14e
GIT binary patch
literal 1211
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583dSsRCB}QA|S<*?&#~tz{ps-dGfvvAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn=geV#6kAr-gYUfs@kz=4O^(2MW=hX4ES9b9{WiFw0LuSrYJ
zoXNSdYg_VNeb1s<bMKvht?20&%-|8k;4z8GVUh^Lq$La!R9G8SG#OMp85KOa7(B_4
zVk}@GQzth2SP!sL<{WfGso_P0nM@Bjs1<GyL&*qmgljNjkh*aJOcoTS40MMsVX$bT
vIJu!1iV*-PvLr@*5QB^(`T63{OZH%uk898Ey)zeBGB9|$`njxgN@xNAtJFa=

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-16-linear-tRNS.png b/extern/libpng/contrib/testpngs/rgb-16-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..3dfa6a6ad044993b59cec8ff49f078d1b9cd1d91
GIT binary patch
literal 1211
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583dSsRCB}QA|S<*?&#~tz}U9H@Wr%vAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn=geV#6kAr-gYUfs@kz=4O^(2MW=hX4ES9b9{WiFw0LuSrYJ
zoXNSdYg_VNeb1s<bMKvht?20&%-|8k;4z8GVUh^Lq$La!R9G8SG#OMp85KOa7(B_4
zVk}@GQzth2SP!sL<{WfGso_P0nM@Bjs1<GyL&*qmgljNjkh*aJOcoTS40MMsVX$bT
vIJu!1iV*-PvLr@*5QB^(`T63{OZH%uk898Ey)zeBGB9|$`njxgN@xNAkxD^j

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-16-linear.png b/extern/libpng/contrib/testpngs/rgb-16-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..3dfa6a6ad044993b59cec8ff49f078d1b9cd1d91
GIT binary patch
literal 1211
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583dSsRCB}QA|S<*?&#~tz}U9H@Wr%vAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn=geV#6kAr-gYUfs@kz=4O^(2MW=hX4ES9b9{WiFw0LuSrYJ
zoXNSdYg_VNeb1s<bMKvht?20&%-|8k;4z8GVUh^Lq$La!R9G8SG#OMp85KOa7(B_4
zVk}@GQzth2SP!sL<{WfGso_P0nM@Bjs1<GyL&*qmgljNjkh*aJOcoTS40MMsVX$bT
vIJu!1iV*-PvLr@*5QB^(`T63{OZH%uk898Ey)zeBGB9|$`njxgN@xNAkxD^j

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-16-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/rgb-16-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..2cf2209e01d6eb8253a77f91f1de55fa8a4900fd
GIT binary patch
literal 1164
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583dSsRCB}QA`q`Q$lZzA{J3v0kfT%L8d2h$
zUr<?;nVwO?uu{Ruz|dF+NSG>k<!9t6IG5(-W#*-4B<3nO<(KEA7S)y%{{!kP$qb1o
z@ySe1%_{~<18qpnV_@L8uG{0w*Q_AWy8hE6Mw#8Y(<=m9rh6&zG;ZYfU(Xp^Z?B!q
zbx$IZ>vm^Vo;z2^tXi!VIR(A<F7+48+B~hVeRD}tQQpDqxMlohn{VA$dicI=;kjG;
zjQWx_#Alzne1g~5NUQ0_jJ0YE49tC=E{-7;x87de&UnCqhuP4J@BN1V`|cfFdw_{~
z!%nYBOU|6hxv^_o@?Cw;qFHnAoqw(9=@-o45yapziOFG-2*ac$3=>pX8&otIR6H3K
zJh>P=$&g|!U?Ec{Hv3o)uu|q6bVI4(MTD754>+h5ZV*Gs2yldJFk+CpaRE#g6r~Jw
zhc02TXref|p%{u004TB~Mtu;2j3fE^;?GO=V3m(+&+WZ47g#bdc)I$ztaD0e0stU;
BHA?^h

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-16-sRGB.png b/extern/libpng/contrib/testpngs/rgb-16-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..2cf2209e01d6eb8253a77f91f1de55fa8a4900fd
GIT binary patch
literal 1164
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583dSsRCB}QA`q`Q$lZzA{J3v0kfT%L8d2h$
zUr<?;nVwO?uu{Ruz|dF+NSG>k<!9t6IG5(-W#*-4B<3nO<(KEA7S)y%{{!kP$qb1o
z@ySe1%_{~<18qpnV_@L8uG{0w*Q_AWy8hE6Mw#8Y(<=m9rh6&zG;ZYfU(Xp^Z?B!q
zbx$IZ>vm^Vo;z2^tXi!VIR(A<F7+48+B~hVeRD}tQQpDqxMlohn{VA$dicI=;kjG;
zjQWx_#Alzne1g~5NUQ0_jJ0YE49tC=E{-7;x87de&UnCqhuP4J@BN1V`|cfFdw_{~
z!%nYBOU|6hxv^_o@?Cw;qFHnAoqw(9=@-o45yapziOFG-2*ac$3=>pX8&otIR6H3K
zJh>P=$&g|!U?Ec{Hv3o)uu|q6bVI4(MTD754>+h5ZV*Gs2yldJFk+CpaRE#g6r~Jw
zhc02TXref|p%{u004TB~Mtu;2j3fE^;?GO=V3m(+&+WZ47g#bdc)I$ztaD0e0stU;
BHA?^h

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-16-tRNS.png b/extern/libpng/contrib/testpngs/rgb-16-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..28643528d6bc2fbfd8c9da72c9fb60eec0d23e48
GIT binary patch
literal 1151
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583dSsRCB}QA|Rzx;u=xnoL^8`l$oAU!mv`o
z$iUE82S}JIc;#p0DL9wr<z?ojXC&q-IOUh;q!!hd6#oP2E6EIrDDlZmPR%O@N&^i|
z&0}ETxUSpd%h#+R(7OK9BSx9sxzj5ITc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On
z$E;ed6*&dH_b&Ap%-TGyuYGe#Qc>Q)?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy
z*hs7C#*DRU3=GVDo-U3d6}R4A-OhNxfrr`9i|_r0|NHJ8Tzi0tdBaYxNlVV0$+@v>
zTk>6f&!Sm#@11|G=;;^C;1R^&F^S1xk_f}3B@7c(SQ}I{8B{zO6+F2ZJjsw^EMOs1
zCpP<753o|^9CSme;YEa*Ob<Ay6>bni$p~<SYcOJvx^V$a78IonbcZfsuxO$<xuF<}
q5dbK%Bu0G@gN!5j`Qpz@_F$EdYtQYyGZ$DgFnGH9xvX<aXaWHEcrsf6

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-16.png b/extern/libpng/contrib/testpngs/rgb-16.png
new file mode 100644
index 0000000000000000000000000000000000000000..28643528d6bc2fbfd8c9da72c9fb60eec0d23e48
GIT binary patch
literal 1151
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583dSsRCB}QA|Rzx;u=xnoL^8`l$oAU!mv`o
z$iUE82S}JIc;#p0DL9wr<z?ojXC&q-IOUh;q!!hd6#oP2E6EIrDDlZmPR%O@N&^i|
z&0}ETxUSpd%h#+R(7OK9BSx9sxzj5ITc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On
z$E;ed6*&dH_b&Ap%-TGyuYGe#Qc>Q)?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy
z*hs7C#*DRU3=GVDo-U3d6}R4A-OhNxfrr`9i|_r0|NHJ8Tzi0tdBaYxNlVV0$+@v>
zTk>6f&!Sm#@11|G=;;^C;1R^&F^S1xk_f}3B@7c(SQ}I{8B{zO6+F2ZJjsw^EMOs1
zCpP<753o|^9CSme;YEa*Ob<Ay6>bni$p~<SYcOJvx^V$a78IonbcZfsuxO$<xuF<}
q5dbK%Bu0G@gN!5j`Qpz@_F$EdYtQYyGZ$DgFnGH9xvX<aXaWHEcrsf6

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-8-1.8-tRNS.png b/extern/libpng/contrib/testpngs/rgb-8-1.8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..afff9df22663f6a555f7c11dbfcbe68c3ed02654
GIT binary patch
literal 837
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K58911L)MWvCLm<VH?&#~tz{ps-dGfvvAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5*h+%@f`R4%p(=Ap
z15iY##5JPCIlrK?C^J2ygkhzEk%6JH4v;Wa@XF7~Q*bWL%gfA5&q&NwaLO;wNiC`^
zDgFo4SCSbLQR0)CoSIh*lm;4@n#aJvab35^m#<ktpmqJHM~pJNbEj7bwoLa@;%VH-
z?Z2Kgw%%Slnd_cJBG>KCsyuhDj#;%@D{=~Y?_KIIn6-IYU;E~gq@uio*>TJG%QoM-
zuk`SJ+ro3V_8IjhYlzQ2b@>FZv5{8OjTvi!K4oI_ba4!+xb^ljBQJvj5A(sihWgVQ
zGn!(Hxn|X<YHnWp+KT_$t1qovSsEA|7!();7&sVM7?>Cssm^72z)Bl~;ZCNd>p_+<
q?w~=iz+DdtaE=4qv<Uu$FO2aInZkd^%IpHBNCr<=KbLh*2~7ah7n$?`

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-8-1.8.png b/extern/libpng/contrib/testpngs/rgb-8-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..d4bb12afa1101bf338bf992d67761ea1a8f0ef66
GIT binary patch
literal 819
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K58911L)MWvCLm<VH?&#~tz{ps-dGfvvAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn;~Y@RNTAr-gYUS{NFP~c%cnAcE$T4P32Y%$lY8dc5BYhPRO
zUwieXbt_8)g9C#Cg8%~u0}BHa10&VBEDu;|V=&ywv~)el62=`g2o|{OK>^NjfSVS<
cpYVk-{vlKN?^u~#z!b^g>FVdQ&MBb@050yAXaE2J

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-8-linear-tRNS.png b/extern/libpng/contrib/testpngs/rgb-8-linear-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..5a2ed9f009af9200ffa7c6485accbfe524a6d056
GIT binary patch
literal 837
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K58911L)MWvCLm<VH?&#~tz}U9H@Wr%vAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5*h+%@f`R4%p(=Ap
z15iY##5JPCIlrK?C^J2ygkhzEk%6JH4v;Wa@XF7~Q*bWL%gfA5&q&NwaLO;wNiC`^
zDgFo4SCSbLQR0)CoSIh*lm;4@n#aJvab35^m#<ktpmqJHM~pJNbEj7bwoLa@;%VH-
z?Z2Kgw%%Slnd_cJBG>KCsyuhDj#;%@D{=~Y?_KIIn6-IYU;E~gq@uio*>TJG%QoM-
zuk`SJ+ro3V_8IjhYlzQ2b@>FZv5{8OjTvi!K4oI_ba4!+xb^ljBQJvj5A(sihWgVQ
zGn!(Hxn|X<YHnWp+KT_$t1qovSsEA|7!();7&sVM7?>Cssm^72z)Bl~;ZCNd>p_+<
q?w~=iz+DdtaE=4qv<Uu$FO2aInZkd^%IpHBNCr<=KbLh*2~7ZSftn@&

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-8-linear.png b/extern/libpng/contrib/testpngs/rgb-8-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..7c42b0840831216f7818e8b71a39e1e30b40db97
GIT binary patch
literal 819
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K58911L)MWvCLm<VH?&#~tz}U9H@Wr%vAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn;~Y@RNTAr-gYUS{NFP~c%cnAcE$T4P32Y%$lY8dc5BYhPRO
zUwieXbt_8)g9C#Cg8%~u0}BHa10&VBEDu;|V=&ywv~)el62=`g2o|{OK>^NjfSVS<
cpYVk-{vlKN?^u~#z!b^g>FVdQ&MBb@0LR6bng9R*

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-8-sRGB-tRNS.png b/extern/libpng/contrib/testpngs/rgb-8-sRGB-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..f8b4ecbdc69d05e45b655031ea6856ebcf5cb672
GIT binary patch
literal 790
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K58911L)MWvCLlCbx$lZzA{J3v0ki%9I<QEK7
z0EDW{B@I9kof6lG66gGa%A(Blj1q>G3PuKo#yUX4RKY7hBTvD(G%qhRFFhkMSHUU2
zJSVlNwxswUP+v)ANJNQGW^!s?F;E(4U}_!%1IKmU9$&s@1%cM}pB^#F?9QEDA=onA
zONpm(Be(y0&e(c;?PRWd5{X>5JFD{CxjJUmYOTmA=)HHTzhKtpX?^XROOlH64ra$K
z<1gEM>%P*%_iYQ$-P&i=m#iT^`_$zVyv9aaO*dw&RbyaaV)Jxy45_&F_A(<cg8~op
z!Muk0(;73HVvD(E)u?K2Ui;dL|JtiBty@_d7#tWB7z7wN7+4sX7#OL}WqH6#8-w9a
wrlspamN4$1L9oDG4+?OO1KhL-{)8`#@ei58f5*z~0;Wg?Pgg&ebxsLQ0N@ag3;+NC

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-8-sRGB.png b/extern/libpng/contrib/testpngs/rgb-8-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..4acae649d387ee0a259428e9e210d2dc3e4f98a4
GIT binary patch
literal 772
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K58911L)MWvCLlCbx$lZzA{J3v0kfT%L8d2h$
zUr<?;nVwO?uu{Ruz|dF+NSG>k<!9t6IG5(-W#*-4B<3nO<(KEA7S)y%{{!kP$qb1o
z@ySe1%_{~<18qpnV_@L8uG{0w*Q_AWy8hE6Mw#8Y(<=m9rh6&zG;ZYfU(Xp^Z?B!q
zbx$IZ>vm^Vo;z2^tXi!VIR(A<F7+48+B~hVeRD}tQQpDqxMlohn{VA$dicI=;kjG;
zjQWx_#Alzne1g~5NUQ0_jJ0YE3`}gEE{-7;x87c6<YiFcVLq7GP=8uuMpJAt*Q^><
z&CP3HTk&6e^`&(yO9O)gg93v90|x^O0}}%y)wwJWSZQN0+{v_bJ;)Nq9W)3Qxa&ay
i&T)X77QvtJg)#miQ~2*#nO(pX$>8bg=d#Wzp$PyHMvH&|

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-8-tRNS.png b/extern/libpng/contrib/testpngs/rgb-8-tRNS.png
new file mode 100644
index 0000000000000000000000000000000000000000..cdb1642ebad2e8e697f0e48a7ff5b2376ad51661
GIT binary patch
literal 777
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K58911L)MWvCLm<Ug666;Q6azw4=8^`Wh)#)X
zM2T~LL1j^9dPWJuN(CbWLt`BvVXEMjpOL5FT$-1cnU|iCn5*EFU!Id%R9jN~52&vs
zGbEzKCo?%UuNWu|G%z)ffq~<?ZjUctvw}eD`cID-Wp?LIuMljR?xn=jxRKj`J!fpa
zy>>F!J&8oF+nrT;?pz(SYPDA66!hM^)L$@b^R&M9%_T`ic?YxOmhqQuzI9*e;rq6Q
z=WgvY>PyxTpMC1`30`9(t)?3@)~YcuFtK^MIEGZ*dV86XmqCGt`Cwi{{b`LEO|ivX
zvuac|H?Mtd#eeP9m)5N;4Gazp3Jd}a91JWBObm=v=dwItrH#RGC)3jPAWIl`&>&dg
lt_KA;#{q6y1b@O8#`uR!;lE>Lb^%i)gQu&X%Q~loCIAqyiyQy|

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-8.png b/extern/libpng/contrib/testpngs/rgb-8.png
new file mode 100644
index 0000000000000000000000000000000000000000..e69c71bfd57998b71aba94b56dee8a0d20265ec7
GIT binary patch
literal 759
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K58911L)MWvCLm;J7;u=xnoL^8`l$oAU!mv`o
z$iUE82S}JIc;#p0DL9wr<z?ojXC&q-IOUh;q!!hd6#oP2E6EIrDDlZmPR%O@N&^i|
z&0}ETxUSpd%h#+R(7OK9BSx9sxzj5ITc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On
z$E;ed6*&dH_b&Ap%-TGyuYGe#Qc>Q)?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy
z*hs7C#*DRU3=B+co-U3d6}R4AX5?j1;9)+P*HC|2V@6YKG1sgbRn5(7Ut95Cd-bJt
zD@y}|1A_vC00RdD3j-4aBh|Sq4_IkqFx<(sbUnxt#vL>W7P#v{0nTxNn-;;J@P#q{
XAyfG8SeaeG6v^P}>gTe~DWM4fcDIO-

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-alpha-16-1.8.png b/extern/libpng/contrib/testpngs/rgb-alpha-16-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..ad65d150e23f08e419facaa791faa5d17c4784d4
GIT binary patch
literal 1437
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583fpX6wjj)RUpNZ?&#~tz{ps-dGfvvAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn;q1)eUBAr-gYUR%j{z<`Iv(fjAz<A2MgCkY)gac`5qm2v;j
znKNfj=_E&Od%TC;bJCjRZF8>gjpqll7BeV#1~E)f@nm$Eq{7PJIZ1>;g<Jtm29HTg
zfaXnNYEbdyVwj{trT_&_K=B3_gZl(>-GJf`)&^w{N&*JWRb&SYs-q~2EV!E}j4ZgD
z7$0y@oPt1(TEbAkLU9s8xQg;*4RI9Z$r|J)>SZ+<M=IsDK9XJa=c0It`CY>uQAKNj
PWgmm5tDnm{r-UW|VN`y;

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-alpha-16-linear.png b/extern/libpng/contrib/testpngs/rgb-alpha-16-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..1f399003173a558a55e7a0312f4a796b39cf99a2
GIT binary patch
literal 1437
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583fpX6wjj)RUpNZ?&#~tz}U9H@Wr%vAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn;q1)eUBAr-gYUR%j{z<`Iv(fjAz<A2MgCkY)gac`5qm2v;j
znKNfj=_E&Od%TC;bJCjRZF8>gjpqll7BeV#1~E)f@nm$Eq{7PJIZ1>;g<Jtm29HTg
zfaXnNYEbdyVwj{trT_&_K=B3_gZl(>-GJf`)&^w{N&*JWRb&SYs-q~2EV!E}j4ZgD
z7$0y@oPt1(TEbAkLU9s8xQg;*4RI9Z$r|J)>SZ+<M=IsDK9XJa=c0It`CY>uQAKNj
PWgmm5tDnm{r-UW|a_)Zc

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-alpha-16-sRGB.png b/extern/libpng/contrib/testpngs/rgb-alpha-16-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..d9cea633a5e781eedf91a5bc4ffdad0e9f16e799
GIT binary patch
literal 1390
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583fpX6wjj)RS>T@$lZzA{J3v0kfT%L8d2h$
zUr<?;nVwO?uu{Ruz|dF+NSG>k<!9t6IG5(-W#*-4B<3nO<(KEA7S)y%{{!kP$qb1o
z@ySe1%_{~<18qpnV_@L8uG{0w*Q_AWy8hE6Mw#8Y(<=m9rh6&zG;ZYfU(Xp^Z?B!q
zbx$IZ>vm^Vo;z2^tXi!VIR(A<F7+48+B~hVeRD}tQQpDqxMlohn{VA$dicI=;kjG;
zjQWx_#Alzne1g~5NUQ0_jJ0YE3@innE{-7;x87b`$#}qkhsDwR=iK9e%cUm?9Wrrm
zlfRX5|InE;XHMxPM{Rq&huw41n&fSBuJ4WK2eKA3D0l`jOi=M;beN>V%HTOkgh7Q|
z0Zj&vNlSp{O=4<L@#JEdq(Y_u1x`Tm1{Z_-1ajSg;t$paWe-XM2F+Du2MnsCD2pt(
zn<$JdxSJRsa8R6rK#p3%P{2ZQ5<<9&@?;Hh6y?bp<R<E6H5o@L<+VPNUG?Xpc!~L4
V!yQpYYk*}RgQu&X%Q~loCIEOTa@GI<

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-alpha-16.png b/extern/libpng/contrib/testpngs/rgb-alpha-16.png
new file mode 100644
index 0000000000000000000000000000000000000000..59262397eb5b4adc3e833e066f0cc19323a53d88
GIT binary patch
literal 1377
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K583fpX6wjj)RUoBP;u=xnoL^8`l$oAU!mv`o
z$iUE82S}JIc;#p0DL9wr<z?ojXC&q-IOUh;q!!hd6#oP2E6EIrDDlZmPR%O@N&^i|
z&0}ETxUSpd%h#+R(7OK9BSx9sxzj5ITc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On
z$E;ed6*&dH_b&Ap%-TGyuYGe#Qc>Q)?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy
z*hs7C#*DRU3=Av<o-U3d6}R4ATgiC9fQQA=`{&%_f6JvO2^}(VZ<D{3asSYnGiOfe
zBu8y~yocR$(wgLLbFS}==LfPDGbnflF-%bLWOSIM!ph(|NrXX#Tmel6k4Z~_=1pR1
zQ1Rqqn506c00mA!@dg)z`vh{`fZ`9<24xRQ0tU@hWCskYqbQ3kxSJ@9EV!E(A8=5d
zf<TU1!cf3MaS}qfit=O)aTMjr8ssMGWi=T`D&@64l3n%ZqIik<UBewwMQea%AA_f>
KpUXO@geCyOk#FVz

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-alpha-8-1.8.png b/extern/libpng/contrib/testpngs/rgb-alpha-8-1.8.png
new file mode 100644
index 0000000000000000000000000000000000000000..f4d08ec04714b59ce33cb9cdf731e898561b42a2
GIT binary patch
literal 919
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K5893O0R7}x|G$6&2?&#~tz{ps-dGfvvAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn;~S)MMAAr-gYUfIcez=4O^(QDuG|9y84J(Xg*%+S16MblV%
z=eqp(gk^r~na`*&C@?et^)PTyjlt0%>;Q@e76t(ZYB2;D)T!)B1)zWZsO(Aypnqi;
msTr1_$f3H&sb%Dc2kiS){w-X1V!aFl5O})!xvX<aXaWGLZlAFL

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-alpha-8-linear.png b/extern/libpng/contrib/testpngs/rgb-alpha-8-linear.png
new file mode 100644
index 0000000000000000000000000000000000000000..b4f8bc8294125cd98722d86e7b950ccfdbfbfe37
GIT binary patch
literal 919
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K5893O0R7}x|G$6&2?&#~tz}U9H@Wr%vAYUQb
zBgmJ5p-PQ`p`nF=;TKS-;RORjsR0ASs{{rHs~HRo;stYd1=;{5bV^(!N}TfxDvL7H
zGfEg%Di|3U8tVWFQw6X5j64PB(!9LPy!4F3Tm`56@|@J7+LGdbKz${dArU1$naQbn
z#XxDGgHrPt7&xx$_W1HOD+si%|MZAaW_RxN3c;4?UP?TT8@c`0bH>)&YbSHvlSt&c
z-C33A&ebuiR%=C0LGQgw{ROi&PwQ*nT#{6jcQ89{8GqU4TlbY7zHeK2?$$n|zGMyY
z*{3d_;59bVYPvCFEzn;~S)MMAAr-gYUfIcez=4O^(QDuG|9y84J(Xg*%+S16MblV%
z=eqp(gk^r~na`*&C@?et^)PTyjlt0%>;Q@e76t(ZYB2;D)T!)B1)zWZsO(Aypnqi;
msTr1_$f3H&sb%Dc2kiS){w-X1V!aFl5O})!xvX<aXaWFM+@IqB

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-alpha-8-sRGB.png b/extern/libpng/contrib/testpngs/rgb-alpha-8-sRGB.png
new file mode 100644
index 0000000000000000000000000000000000000000..f06e7f837cb38310c26d85b53f719fac7533281e
GIT binary patch
literal 872
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K5893O0R7}x|G!U;i$lZzA{J3v0kfT%L8d2h$
zUr<?;nVwO?uu{Ruz|dF+NSG>k<!9t6IG5(-W#*-4B<3nO<(KEA7S)y%{{!kP$qb1o
z@ySe1%_{~<18qpnV_@L8uG{0w*Q_AWy8hE6Mw#8Y(<=m9rh6&zG;ZYfU(Xp^Z?B!q
zbx$IZ>vm^Vo;z2^tXi!VIR(A<F7+48+B~hVeRD}tQQpDqxMlohn{VA$dicI=;kjG;
zjQWx_#Alzne1g~5NUQ0_jJ0YE3`|*`E{-7;x87da$$P+ohuP6<-}3)`cMm<4V!F)G
zyjDfiSbFEW{P=`re(Rafs4yrnGywH5a8QlG(ID&q3Re~e0S0O@1Q^t*>`DcofBmTJ
sN(Z2SWf-X$mY~R?y2q(y<cA0B`&9ldTzF!=3<D5&y85}Sb4q9e0L%E3$p8QV

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/testpngs/rgb-alpha-8.png b/extern/libpng/contrib/testpngs/rgb-alpha-8.png
new file mode 100644
index 0000000000000000000000000000000000000000..e15d4913f2d3df822129e6a771df02f0b31434f3
GIT binary patch
literal 859
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K5893O0R7}x|G$5r@;u=xnoL^8`l$oAU!mv`o
z$iUE82S}JIc;#p0DL9wr<z?ojXC&q-IOUh;q!!hd6#oP2E6EIrDDlZmPR%O@N&^i|
z&0}ETxUSpd%h#+R(7OK9BSx9sxzj5ITc&#{@icDa_FvB#TW_zO%ymy9k?VG6Rh~On
z$E;ed6*&dH_b&Ap%-TGyuYGe#Qc>Q)?6_t8Wt(r^S9<uqZQ;3F`;7XMHN<D1x_pAy
z*hs7C#*DRU3=B+Jo-U3d6}R4A*~xprfrr`AYv1z!eRmH%m14Tg(7aYf(^z`vy8QTr
zWq#|K&!{jcFf;)5FmO<f!O<Y>018SL1_1_YF$5UYsq9Jxpnv_S>`Diqe`Oe{8J3{P
hp}NPZW#oqk?E6&yEnIkFy$k~oc)I$ztaD0e0ssVnkl6qL

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/tools/README.txt b/extern/libpng/contrib/tools/README.txt
new file mode 100644
index 0000000000..f53be6df9b
--- /dev/null
+++ b/extern/libpng/contrib/tools/README.txt
@@ -0,0 +1,27 @@
+This directory (contrib/tools) contains tools used by the authors of libpng.
+
+Code and data placed in this directory is not required to build libpng,
+however the code in this directory has been used to generate data or code in
+the body of the libpng source.  The source code identifies where this has
+been done.  Code in this directory may not compile on all operating systems
+that libpng supports.
+
+NO COPYRIGHT RIGHTS ARE CLAIMED TO ANY OF THE FILES IN THIS DIRECTORY.
+
+To the extent possible under law, the authors have waived all copyright and
+related or neighboring rights to this work.  This work is published from:
+United States.
+
+The files may be used freely in any way.
+
+The source code and comments in this directory are the original work of the
+people named below.  No other person or organization has made contributions to
+the work in this directory.
+
+ORIGINAL AUTHORS
+    The following people have contributed to the code in this directory.  None
+    of the people below claim any rights with regard to the contents of this
+    directory.
+
+    John Bowler <jbowler at acm.org>
+    Glenn Randers-Pehrson <glennrp at users.sourceforge.net>
diff --git a/extern/libpng/contrib/tools/checksum-icc.c b/extern/libpng/contrib/tools/checksum-icc.c
new file mode 100644
index 0000000000..581e7088a6
--- /dev/null
+++ b/extern/libpng/contrib/tools/checksum-icc.c
@@ -0,0 +1,102 @@
+/* checksum-icc.c
+ *
+ * Copyright (c) 2013 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Generate crc32 and adler32 checksums of the given input files, used to
+ * generate check-codes for use when matching ICC profiles within libpng.
+ */
+#include <stdio.h>
+
+#include <zlib.h>
+
+static int
+read_one_file(FILE *ip, const char *name)
+{
+   uLong length = 0;
+   uLong a32 = adler32(0, NULL, 0);
+   uLong c32 = crc32(0, NULL, 0);
+   Byte header[132];
+
+   for (;;)
+   {
+      int ch = getc(ip);
+      Byte b;
+
+      if (ch == EOF) break;
+
+      b = (Byte)ch;
+
+      if (length < sizeof header)
+         header[length] = b;
+
+      ++length;
+      a32 = adler32(a32, &b, 1);
+      c32 = crc32(c32, &b, 1);
+   }
+
+   if (ferror(ip))
+      return 0;
+
+   /* Success */
+   printf("PNG_ICC_CHECKSUM(0x%8.8lx, 0x%8.8lx,\n   PNG_MD5("
+      "0x%2.2x%2.2x%2.2x%2.2x, 0x%2.2x%2.2x%2.2x%2.2x, 0x%2.2x%2.2x%2.2x%2.2x,"
+      " 0x%2.2x%2.2x%2.2x%2.2x), %d,\n"
+      "   \"%4.4d/%2.2d/%2.2d %2.2d:%2.2d:%2.2d\", %lu, \"%s\")\n",
+      (unsigned long)a32, (unsigned long)c32,
+      header[84], header[85], header[86], header[87],
+      header[88], header[89], header[90], header[91],
+      header[92], header[93], header[94], header[95],
+      header[96], header[97], header[98], header[99],
+#     define u16(x) (header[x] * 256 + header[x+1])
+#     define u32(x) (u16(x) * 65536 + u16(x+2))
+      u32(64), u16(24), u16(26), u16(28), u16(30), u16(32), u16(34),
+      (unsigned long)length, name);
+
+   return 1;
+}
+
+int main(int argc, char **argv)
+{
+   int err = 0;
+
+   printf("/* adler32, crc32, MD5[16], intent, date, length, file-name */\n");
+
+   if (argc > 1)
+   {
+      int i;
+
+      for (i=1; i<argc; ++i)
+      {
+         FILE *ip = fopen(argv[i], "rb");
+
+         if (ip == NULL || !read_one_file(ip, argv[i]))
+         {
+            err = 1;
+            perror(argv[i]);
+            fprintf(stderr, "%s: read error\n", argv[i]);
+            printf("/* ERROR: %s */\n", argv[i]);
+         }
+
+         (void)fclose(ip);
+      }
+   }
+
+   else
+   {
+      if (!read_one_file(stdin, "-"))
+      {
+         err = 1;
+         perror("stdin");
+         fprintf(stderr, "stdin: read error\n");
+         printf("/* ERROR: stdin */\n");
+      }
+   }
+
+   return err;
+}
diff --git a/extern/libpng/contrib/tools/chkfmt b/extern/libpng/contrib/tools/chkfmt
new file mode 100755
index 0000000000..95181fde2e
--- /dev/null
+++ b/extern/libpng/contrib/tools/chkfmt
@@ -0,0 +1,144 @@
+#!/bin/sh
+
+# chkfmt
+#
+# COPYRIGHT: Written by John Cunningham Bowler, 2010.
+# To the extent possible under law, the author has waived all copyright and
+# related or neighboring rights to this work.  This work is published from:
+# United States.
+#
+# Check the format of the source files in the current directory - checks for a
+# line length of 80 characters max and no tab characters.
+#
+# Optionally arguments are files or directories to check.
+#
+# -v: output the long lines (makes fixing them easier)
+# -e: spawn an editor for each file that needs a change ($EDITOR must be
+#     defined).  When using -e the script MUST be run from an interactive
+#     command line.
+verbose=
+edit=
+vers=
+test "$1" = "-v" && {
+   shift
+   verbose=yes
+}
+test "$1" = "-e" && {
+   shift
+   if test -n "$EDITOR"
+   then
+      edit=yes
+
+      # Copy the standard streams for the editor
+      exec 3>&0 4>&1 5>&2
+   else
+      echo "chkfmt -e: EDITOR must be defined" >&2
+      exit 1
+   fi
+}
+
+# Function to edit a single file - if the file isn't changed ask the user
+# whether or not to continue.  This stuff only works if the script is run from
+# the command line (otherwise, don't specify -e or you will be sorry).
+doed(){
+   cp "$file" "$file".orig
+   "$EDITOR" "$file" 0>&3 1>&4 2>&5 3>&- 4>&- 5>&- || exit 1
+   if cmp -s "$file".orig "$file"
+   then
+      rm "$file".orig
+      echo -n "$file: file not changed, type anything to continue: " >&5
+      read ans 0>&3
+      test -n "$ans" || return 1
+   fi
+   return 0
+}
+
+# In beta versions the version string which appears in files can be a little
+# long and cause spuriously overlong lines.  To avoid this substitute the version
+# string with a 'standard' version a.b.cc before checking for long lines.
+if test -r png.h
+then
+   vers="`sed -n -e \
+   's/^#define PNG_LIBPNG_VER_STRING .\([0-9]\.[0-9]\.[0-9][0-9a-z]*\).$/\1/p' \
+   png.h`"
+   echo "chkfmt: checking version $vers"
+fi
+if test -z "$vers"
+then
+   echo "chkfmt: png.h not found, ignoring version number" >&2
+fi
+
+test -n "$1" || set -- .
+find "$@" \( -type d \( -name '.git' -o -name '.libs' -o -name 'projects' \) \
+   -prune \) -o \( -type f \
+   ! -name '*.[oa]' ! -name '*.l[oa]' !  -name '*.png' ! -name '*.out' \
+   ! -name '*.jpg' ! -name '*.patch' ! -name '*.obj' ! -name '*.exe' \
+   ! -name '*.com' ! -name '*.tar.*' ! -name '*.zip' ! -name '*.ico' \
+   ! -name '*.res' ! -name '*.rc' ! -name '*.mms' ! -name '*.rej' \
+   ! -name '*.dsp' ! -name '*.orig' ! -name '*.dfn' ! -name '*.swp' \
+   ! -name '~*' ! -name '*.3' \
+   ! -name 'missing' ! -name 'mkinstalldirs' ! -name 'depcomp' \
+   ! -name 'aclocal.m4' ! -name 'install-sh' ! -name 'Makefile.in' \
+   ! -name 'ltmain.sh' ! -name 'config*' -print \) | {
+   st=0
+   while read file
+   do
+      case "$file" in
+      *.mak|*[Mm]akefile.*|*[Mm]akefile)
+         # Makefiles require tabs, dependency lines can be this long.
+         check_tabs=
+         line_length=100;;
+      *.awk)
+         # Includes literal tabs
+         check_tabs=
+         # The following is arbitrary
+         line_length=132;;
+      *contrib/*/*.[ch])
+         check_tabs=yes
+         line_length=96;;
+      *)
+         check_tabs=yes
+         line_length=80;;
+      esac
+
+      # Note that vers can only contain 0-9, . and a-z
+      if test -n "$vers"
+      then
+         sed -e "s/$vers/a.b.cc/g" "$file" >"$file".$$
+      else
+         cp "$file" "$file".$$
+      fi
+      splt="`fold -$line_length "$file".$$ | diff -c "$file".$$ -`"
+      rm "$file".$$
+
+      if test -n "$splt"
+      then
+         echo "$file: lines too long"
+         st=1
+         if test -n "$EDITOR" -a -n "$edit"
+         then
+            doed "$file" || exit 1
+         elif test -n "$verbose"
+         then
+            echo "$splt"
+         fi
+      fi
+      if test -n "$check_tabs"
+      then
+         tab="`tr -c -d '\t' <"$file"`"
+         if test -n "$tab"
+         then
+            echo "$file: file contains tab characters"
+            st=1
+            if test -n "$EDITOR" -a -n "$edit"
+            then
+               doed "$file" || exit 1
+            elif test -n "$verbose"
+            then
+               echo "$splt"
+            fi
+         fi
+      fi
+   done
+   exit $st
+}
diff --git a/extern/libpng/contrib/tools/cvtcolor.c b/extern/libpng/contrib/tools/cvtcolor.c
new file mode 100644
index 0000000000..e6793c7d59
--- /dev/null
+++ b/extern/libpng/contrib/tools/cvtcolor.c
@@ -0,0 +1,188 @@
+/*-
+ * convert.c
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2013.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Convert 8-bit sRGB or 16-bit linear values to another format.
+ */
+#define _ISOC99_SOURCE 1
+
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+
+#include <fenv.h>
+
+#include "sRGB.h"
+
+static void
+usage(const char *prog)
+{
+   fprintf(stderr,
+      "%s: usage: %s [-linear|-sRGB] [-gray|-color] component{1,4}\n",
+      prog, prog);
+   exit(1);
+}
+
+unsigned long
+component(const char *prog, const char *arg, int issRGB)
+{
+   char *ep;
+   unsigned long c = strtoul(arg, &ep, 0);
+
+   if (ep <= arg || *ep || c > 65535 || (issRGB && c > 255))
+   {
+      fprintf(stderr, "%s: %s: invalid component value (%lu)\n", prog, arg, c);
+      usage(prog);
+   }
+
+   return c;
+}
+
+int
+main(int argc, const char **argv)
+{
+   const char *prog = *argv++;
+   int to_linear = 0, to_gray = 0, to_color = 0;
+   int channels = 0;
+   double c[4];
+
+   /* FE_TONEAREST is the IEEE754 round to nearest, preferring even, mode; i.e.
+    * everything rounds to the nearest value except that '.5' rounds to the
+    * nearest even value.
+    */
+   fesetround(FE_TONEAREST);
+
+   c[3] = c[2] = c[1] = c[0] = 0;
+
+   while (--argc > 0 && **argv == '-')
+   {
+      const char *arg = 1+*argv++;
+
+      if (strcmp(arg, "sRGB") == 0)
+         to_linear = 0;
+
+      else if (strcmp(arg, "linear") == 0)
+         to_linear = 1;
+
+      else if (strcmp(arg, "gray") == 0)
+         to_gray = 1, to_color = 0;
+
+      else if (strcmp(arg, "color") == 0)
+         to_gray = 0, to_color = 1;
+
+      else
+         usage(prog);
+   }
+
+   switch (argc)
+   {
+      default:
+         usage(prog);
+         break;
+
+      case 4:
+         c[3] = component(prog, argv[3], to_linear);
+         ++channels;
+      case 3:
+         c[2] = component(prog, argv[2], to_linear);
+         ++channels;
+      case 2:
+         c[1] = component(prog, argv[1], to_linear);
+         ++channels;
+      case 1:
+         c[0] = component(prog, argv[0], to_linear);
+         ++channels;
+         break;
+      }
+
+   if (to_linear)
+   {
+      int i;
+      int components = channels;
+
+      if ((components & 1) == 0)
+         --components;
+
+      for (i=0; i<components; ++i) c[i] = linear_from_sRGB(c[i] / 255);
+      if (components < channels)
+         c[components] = c[components] / 255;
+   }
+
+   else
+   {
+      int i;
+      for (i=0; i<4; ++i) c[i] /= 65535;
+
+      if ((channels & 1) == 0)
+      {
+         double alpha = c[channels-1];
+
+         if (alpha > 0)
+            for (i=0; i<channels-1; ++i) c[i] /= alpha;
+         else
+            for (i=0; i<channels-1; ++i) c[i] = 1;
+      }
+   }
+
+   if (to_gray)
+   {
+      if (channels < 3)
+      {
+         fprintf(stderr, "%s: too few channels (%d) for -gray\n",
+            prog, channels);
+         usage(prog);
+      }
+
+      c[0] = YfromRGB(c[0], c[1], c[2]);
+      channels -= 2;
+   }
+
+   if (to_color)
+   {
+      if (channels > 2)
+      {
+         fprintf(stderr, "%s: too many channels (%d) for -color\n",
+            prog, channels);
+         usage(prog);
+      }
+
+      c[3] = c[1]; /* alpha, if present */
+      c[2] = c[1] = c[0];
+   }
+
+   if (to_linear)
+   {
+      int i;
+      if ((channels & 1) == 0)
+      {
+         double alpha = c[channels-1];
+         for (i=0; i<channels-1; ++i) c[i] *= alpha;
+      }
+
+      for (i=0; i<channels; ++i) c[i] = nearbyint(c[i] * 65535);
+   }
+
+   else /* to sRGB */
+   {
+      int i = (channels+1)&~1;
+      while (--i >= 0)
+         c[i] = sRGB_from_linear(c[i]);
+
+      for (i=0; i<channels; ++i) c[i] = nearbyint(c[i] * 255);
+   }
+
+   {
+      int i;
+      for (i=0; i<channels; ++i) printf(" %g", c[i]);
+   }
+   printf("\n");
+
+   return 0;
+}
diff --git a/extern/libpng/contrib/tools/genpng.c b/extern/libpng/contrib/tools/genpng.c
new file mode 100644
index 0000000000..0b3f981964
--- /dev/null
+++ b/extern/libpng/contrib/tools/genpng.c
@@ -0,0 +1,881 @@
+/*- genpng
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2015.
+ * Revised by Glenn Randers-Pehrson, 2017, to add buffer-size check.
+ * To the extent possible under law, the authors have waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Generate a PNG with an alpha channel, correctly.
+ *
+ * This is a test case generator; the resultant PNG files are only of interest
+ * to those of us who care about whether the edges of circles are green, red,
+ * or yellow.
+ *
+ * The program generates an RGB+Alpha PNG of a given size containing the given
+ * shapes on a transparent background:
+ *
+ *  genpng width height { shape }
+ *    shape ::= color width shape x1 y1 x2 y2
+ *
+ * 'color' is:
+ *
+ *  black white red green yellow blue brown purple pink orange gray cyan
+ *
+ * The point is to have colors that are linguistically meaningful plus that old
+ * bugbear of the department store dress murders, Cyan, the only color we argue
+ * about.
+ *
+ * 'shape' is:
+ *
+ *  circle: an ellipse
+ *  square: a rectangle
+ *  line: a straight line
+ *
+ * Each shape is followed by four numbers, these are two points in the output
+ * coordinate space (as real numbers) which describe the circle, square, or
+ * line.  The shape is filled if it is preceded by 'filled' (not valid for
+ * 'line') or is drawn with a line, in which case the width of the line must
+ * precede the shape.
+ *
+ * The whole set of information can be repeated as many times as desired:
+ *
+ *    shape ::= color width shape x1 y1 x2 y2
+ *
+ *    color ::= black|white|red|green|yellow|blue
+ *    color ::= brown|purple|pink|orange|gray|cyan
+ *    width ::= filled
+ *    width ::= <number>
+ *    shape ::= circle|square|line
+ *    x1    ::= <number>
+ *    x2    ::= <number>
+ *    y1    ::= <number>
+ *    y2    ::= <number>
+ *
+ * The output PNG is generated by down-sampling a 4x supersampled image using
+ * a bi-cubic filter.  The bi-cubic has a 2 (output) pixel width, so an 8x8
+ * array of super-sampled points contribute to each output pixel.  The value of
+ * a super-sampled point is found using an unfiltered, aliased, infinite
+ * precision image: Each shape from the last to the first is checked to see if
+ * the point is in the drawn area and, if it is, the color of the point is the
+ * color of the shape and the alpha is 1, if not the previous shape is checked.
+ *
+ * This is an aliased algorithm because no filtering is done; a point is either
+ * inside or outside each shape and 'close' points do not contribute to the
+ * sample.  The down-sampling is relied on to correct the error of not using
+ * a filter.
+ *
+ * The line end-caps are 'flat'; they go through the points.  The square line
+ * joins are mitres; the outside of the lines are continued to the point of
+ * intersection.
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <math.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation:
+ */
+#include "../../png.h"
+
+#if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
+
+static const struct color
+{
+   const char *name;
+   double      red;
+   double      green;
+   double      blue;
+} colors[] =
+/* color ::= black|white|red|green|yellow|blue
+ * color ::= brown|purple|pink|orange|gray|cyan
+ */
+{
+   { "black",   0,    0,  0 },
+   { "white",   1,    1,  1 },
+   { "red",     1,    0,  0 },
+   { "green",   0,    1,  0 },
+   { "yellow",  1,    1,  0 },
+   { "blue",    0,    0,  1 },
+   { "brown",  .5, .125,  0 },
+   { "purple",  1,    0,  1 },
+   { "pink",    1,   .5, .5 },
+   { "orange",  1,   .5,  0 },
+   { "gray",    0,   .5, .5 },
+   { "cyan",    0,    1,  1 }
+};
+#define color_count ((sizeof colors)/(sizeof colors[0]))
+
+static const struct color *
+color_of(const char *arg)
+{
+   int icolor = color_count;
+
+   while (--icolor >= 0)
+   {
+      if (strcmp(colors[icolor].name, arg) == 0)
+         return colors+icolor;
+   }
+
+   fprintf(stderr, "genpng: invalid color %s\n", arg);
+   exit(1);
+}
+
+static double
+width_of(const char *arg)
+{
+   if (strcmp(arg, "filled") == 0)
+      return 0;
+
+   else
+   {
+      char *ep = NULL;
+      double w = strtod(arg, &ep);
+
+      if (ep != NULL && *ep == 0 && w > 0)
+         return w;
+   }
+
+   fprintf(stderr, "genpng: invalid line width %s\n", arg);
+   exit(1);
+}
+
+static double
+coordinate_of(const char *arg)
+{
+   char *ep = NULL;
+   double w = strtod(arg, &ep);
+
+   if (ep != NULL && *ep == 0)
+      return w;
+
+   fprintf(stderr, "genpng: invalid coordinate value %s\n", arg);
+   exit(1);
+}
+
+struct arg; /* forward declaration */
+
+typedef int (*shape_fn_ptr)(const struct arg *arg, double x, double y);
+   /* A function to determine if (x,y) is inside the shape.
+    *
+    * There are two implementations:
+    *
+    *    inside_fn: returns true if the point is inside
+    *    check_fn:  returns;
+    *       -1: the point is outside the shape by more than the filter width (2)
+    *        0: the point may be inside the shape
+    *       +1: the point is inside the shape by more than the filter width
+    */
+#define OUTSIDE (-1)
+#define INSIDE  (1)
+
+struct arg
+{
+   const struct color *color;
+   shape_fn_ptr        inside_fn;
+   shape_fn_ptr        check_fn;
+   double              width; /* line width, 0 for 'filled' */
+   double              x1, y1, x2, y2;
+};
+
+/* IMPLEMENTATION NOTE:
+ *
+ * We want the contribution of each shape to the sample corresponding to each
+ * pixel.  This could be obtained by super sampling the image to infinite
+ * dimensions, finding each point within the shape and assigning that a value
+ * '1' while leaving every point outside the shape with value '0' then
+ * downsampling to the image size with sinc; computationally very expensive.
+ *
+ * Approximations are as follows:
+ *
+ * 1) If the pixel coordinate is within the shape assume the sample has the
+ *    shape color and is opaque, else assume there is no contribution from
+ *    the shape.
+ *
+ *    This is the equivalent of aliased rendering or resampling an image with
+ *    a block filter.  The maximum error in the calculated alpha (which will
+ *    always be 0 or 1) is 0.5.
+ *
+ * 2) If the shape is within a square of size 1x1 centered on the pixel assume
+ *    that the shape obscures an amount of the pixel equal to its area within
+ *    that square.
+ *
+ *    This is the equivalent of 'pixel coverage' alpha calculation or resampling
+ *    an image with a bi-linear filter.  The maximum error is over 0.2, but the
+ *    results are often acceptable.
+ *
+ *    This can be approximated by applying (1) to a super-sampled image then
+ *    downsampling with a bi-linear filter.  The error in the super-sampled
+ *    image is 0.5 per sample, but the resampling reduces this.
+ *
+ * 3) Use a better filter with a super-sampled image; in the limit this is the
+ *    sinc() approach.
+ *
+ * 4) Do the geometric calculation; a bivariate definite integral across the
+ *    shape, unfortunately this means evaluating Si(x), the integral of sinc(x),
+ *    which is still a lot of math.
+ *
+ * This code uses approach (3) with a bi-cubic filter and 8x super-sampling
+ * and method (1) for the super-samples.  This means that the sample is either
+ * 0 or 1, depending on whether the sub-pixel is within or outside the shape.
+ * The bi-cubic weights are also fixed and the 16 required weights are
+ * pre-computed here (note that the 'scale' setting will need to be changed if
+ * 'super' is increased).
+ *
+ * The code also calculates a sum to the edge of the filter. This is not
+ * currently used by could be used to optimize the calculation.
+ */
+#if 0 /* bc code */
+scale=10
+super=8
+define bicubic(x) {
+   if (x <= 1) return (1.5*x - 2.5)*x*x + 1;
+   if (x <  2) return (((2.5 - 0.5*x)*x - 4)*x + 2);
+   return 0;
+}
+define sum(x) {
+   auto s;
+   s = 0;
+   while (x < 2*super) {
+      s = s + bicubic(x/super);
+      x = x + 1;
+   }
+   return s;
+}
+define results(x) {
+   auto b, s;
+   b = bicubic(x/super);
+   s = sum(x);
+
+   print "   /*", x, "*/ { ", b, ", ", s, " }";
+   return 1;
+}
+x=0
+while (x<2*super) {
+   x = x + results(x)
+   if (x < 2*super) print ","
+   print "\n"
+}
+quit
+#endif
+
+#define BICUBIC1(x) /*     |x| <= 1 */ ((1.5*(x)* - 2.5)*(x)*(x) + 1)
+#define BICUBIC2(x) /* 1 < |x| <  2 */ (((2.5 - 0.5*(x))*(x) - 4)*(x) + 2)
+#define FILTER_WEIGHT 9 /* Twice the first sum below */
+#define FILTER_WIDTH  2 /* Actually half the width; -2..+2 */
+#define FILTER_STEPS  8 /* steps per filter unit */
+static const double
+bicubic[16][2] =
+{
+   /* These numbers are exact; the weight for the filter is 1/9, but this
+    * would make the numbers inexact, so it is not included here.
+    */
+   /*          bicubic      sum        */
+   /* 0*/ { 1.0000000000, 4.5000000000 },
+   /* 1*/ {  .9638671875, 3.5000000000 },
+   /* 2*/ {  .8671875000, 2.5361328125 },
+   /* 3*/ {  .7275390625, 1.6689453125 },
+   /* 4*/ {  .5625000000,  .9414062500 },
+   /* 5*/ {  .3896484375,  .3789062500 },
+   /* 6*/ {  .2265625000, -.0107421875 },
+   /* 7*/ {  .0908203125, -.2373046875 },
+   /* 8*/ {            0, -.3281250000 },
+   /* 9*/ { -.0478515625, -.3281250000 },
+   /*10*/ { -.0703125000, -.2802734375 },
+   /*11*/ { -.0732421875, -.2099609375 },
+   /*12*/ { -.0625000000, -.1367187500 },
+   /*13*/ { -.0439453125, -.0742187500 },
+   /*14*/ { -.0234375000, -.0302734375 },
+   /*15*/ { -.0068359375, -.0068359375 }
+};
+
+static double
+alpha_calc(const struct arg *arg, double x, double y)
+{
+   /* For [x-2..x+2],[y-2,y+2] calculate the weighted bicubic given a function
+    * which tells us whether a point is inside or outside the shape.  First
+    * check if we need to do this at all:
+    */
+   switch (arg->check_fn(arg, x, y))
+   {
+      case OUTSIDE:
+         return 0; /* all samples outside the shape */
+
+      case INSIDE:
+         return 1; /* all samples inside the shape */
+
+      default:
+      {
+         int dy;
+         double alpha = 0;
+
+#        define FILTER_D (FILTER_WIDTH*FILTER_STEPS-1)
+         for (dy=-FILTER_D; dy<=FILTER_D; ++dy)
+         {
+            double wy = bicubic[abs(dy)][0];
+
+            if (wy != 0)
+            {
+               double alphay = 0;
+               int dx;
+
+               for (dx=-FILTER_D; dx<=FILTER_D; ++dx)
+               {
+                  double wx = bicubic[abs(dx)][0];
+
+                  if (wx != 0 && arg->inside_fn(arg, x+dx/16, y+dy/16))
+                     alphay += wx;
+               }
+
+               alpha += wy * alphay;
+            }
+         }
+
+         /* This needs to be weighted for each dimension: */
+         return alpha / (FILTER_WEIGHT*FILTER_WEIGHT);
+      }
+   }
+}
+
+/* These are the shape functions. */
+/* "square",
+ * { inside_square_filled, check_square_filled },
+ * { inside_square, check_square }
+ */
+static int
+square_check(double x, double y, double x1, double y1, double x2, double y2)
+   /* Is x,y inside the square (x1,y1)..(x2,y2)? */
+{
+   /* Do a modified Cohen-Sutherland on one point, bit patterns that indicate
+    * 'outside' are:
+    *
+    *   x<x1 | x<y1 | x<x2 | x<y2
+    *    0      x      0      x     To the right
+    *    1      x      1      x     To the left
+    *    x      0      x      0     Below
+    *    x      1      x      1     Above
+    *
+    * So 'inside' is (x<x1) != (x<x2) && (y<y1) != (y<y2);
+    */
+   return ((x<x1) ^ (x<x2)) & ((y<y1) ^ (y<y2));
+}
+
+static int
+inside_square_filled(const struct arg *arg, double x, double y)
+{
+   return square_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2);
+}
+
+static int
+square_check_line(const struct arg *arg, double x, double y, double w)
+   /* Check for a point being inside the boundaries implied by the given arg
+    * and assuming a width 2*w each side of the boundaries.  This returns the
+    * 'check' INSIDE/OUTSIDE/0 result but note the semantics:
+    *
+    *          +--------------+
+    *          |              |   OUTSIDE
+    *          |   INSIDE     |
+    *          |              |
+    *          +--------------+
+    *
+    * And '0' means within the line boundaries.
+    */
+{
+   double cx = (arg->x1+arg->x2)/2;
+   double wx = fabs(arg->x1-arg->x2)/2;
+   double cy = (arg->y1+arg->y2)/2;
+   double wy = fabs(arg->y1-arg->y2)/2;
+
+   if (square_check(x, y, cx-wx-w, cy-wy-w, cx+wx+w, cy+wy+w))
+   {
+      /* Inside, but maybe too far; check for the redundant case where
+       * the lines overlap:
+       */
+      wx -= w;
+      wy -= w;
+      if (wx > 0 && wy > 0 && square_check(x, y, cx-wx, cy-wy, cx+wx, cy+wy))
+         return INSIDE; /* between (inside) the boundary lines. */
+
+      return 0; /* inside the lines themselves. */
+   }
+
+   return OUTSIDE; /* outside the boundary lines. */
+}
+
+static int
+check_square_filled(const struct arg *arg, double x, double y)
+{
+   /* The filter extends +/-FILTER_WIDTH each side of each output point, so
+    * the check has to expand and contract the square by that amount; '0'
+    * means close enough to the edge of the square that the bicubic filter has
+    * to be run, OUTSIDE means alpha==0, INSIDE means alpha==1.
+    */
+   return square_check_line(arg, x, y, FILTER_WIDTH);
+}
+
+static int
+inside_square(const struct arg *arg, double x, double y)
+{
+   /* Return true if within the drawn lines, else false, no need to distinguish
+    * INSIDE vs OUTSIDE here:
+    */
+   return square_check_line(arg, x, y, arg->width/2) == 0;
+}
+
+static int
+check_square(const struct arg *arg, double x, double y)
+{
+   /* So for this function a result of 'INSIDE' means inside the actual lines.
+    */
+   double w = arg->width/2;
+
+   if (square_check_line(arg, x, y, w+FILTER_WIDTH) == 0)
+   {
+      /* Somewhere close to the boundary lines. If far enough inside one of
+       * them then we can return INSIDE:
+       */
+      w -= FILTER_WIDTH;
+
+      if (w > 0 && square_check_line(arg, x, y, w) == 0)
+         return INSIDE;
+
+      /* Point is somewhere in the filter region: */
+      return 0;
+   }
+
+   else /* Inside or outside the square by more than w+FILTER_WIDTH. */
+      return OUTSIDE;
+}
+
+/* "circle",
+ * { inside_circle_filled, check_circle_filled },
+ * { inside_circle, check_circle }
+ *
+ * The functions here are analoguous to the square ones; however, they check
+ * the corresponding ellipse as opposed to the rectangle.
+ */
+static int
+circle_check(double x, double y, double x1, double y1, double x2, double y2)
+{
+   if (square_check(x, y, x1, y1, x2, y2))
+   {
+      /* Inside the square, so maybe inside the circle too: */
+      const double cx = (x1 + x2)/2;
+      const double cy = (y1 + y2)/2;
+      const double dx = x1 - x2;
+      const double dy = y1 - y2;
+
+      x = (x - cx)/dx;
+      y = (y - cy)/dy;
+
+      /* It is outside if the distance from the center is more than half the
+       * diameter:
+       */
+      return x*x+y*y < .25;
+   }
+
+   return 0; /* outside */
+}
+
+static int
+inside_circle_filled(const struct arg *arg, double x, double y)
+{
+   return circle_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2);
+}
+
+static int
+circle_check_line(const struct arg *arg, double x, double y, double w)
+   /* Check for a point being inside the boundaries implied by the given arg
+    * and assuming a width 2*w each side of the boundaries.  This function has
+    * the same semantic as square_check_line but tests the circle.
+    */
+{
+   double cx = (arg->x1+arg->x2)/2;
+   double wx = fabs(arg->x1-arg->x2)/2;
+   double cy = (arg->y1+arg->y2)/2;
+   double wy = fabs(arg->y1-arg->y2)/2;
+
+   if (circle_check(x, y, cx-wx-w, cy-wy-w, cx+wx+w, cy+wy+w))
+   {
+      /* Inside, but maybe too far; check for the redundant case where
+       * the lines overlap:
+       */
+      wx -= w;
+      wy -= w;
+      if (wx > 0 && wy > 0 && circle_check(x, y, cx-wx, cy-wy, cx+wx, cy+wy))
+         return INSIDE; /* between (inside) the boundary lines. */
+
+      return 0; /* inside the lines themselves. */
+   }
+
+   return OUTSIDE; /* outside the boundary lines. */
+}
+
+static int
+check_circle_filled(const struct arg *arg, double x, double y)
+{
+   return circle_check_line(arg, x, y, FILTER_WIDTH);
+}
+
+static int
+inside_circle(const struct arg *arg, double x, double y)
+{
+   return circle_check_line(arg, x, y, arg->width/2) == 0;
+}
+
+static int
+check_circle(const struct arg *arg, double x, double y)
+{
+   /* Exactly as the 'square' code.  */
+   double w = arg->width/2;
+
+   if (circle_check_line(arg, x, y, w+FILTER_WIDTH) == 0)
+   {
+      w -= FILTER_WIDTH;
+
+      if (w > 0 && circle_check_line(arg, x, y, w) == 0)
+         return INSIDE;
+
+      /* Point is somewhere in the filter region: */
+      return 0;
+   }
+
+   else /* Inside or outside the square by more than w+FILTER_WIDTH. */
+      return OUTSIDE;
+}
+
+/* "line",
+ * { NULL, NULL },  There is no 'filled' line.
+ * { inside_line, check_line }
+ */
+static int
+line_check(double x, double y, double x1, double y1, double x2, double y2,
+   double w, double expand)
+{
+   /* Shift all the points to (arg->x1, arg->y1) */
+   double lx = x2 - x1;
+   double ly = y2 - y1;
+   double len2 = lx*lx + ly*ly;
+   double cross, dot;
+
+   x -= x1;
+   y -= y1;
+
+   /* The dot product is the distance down the line, the cross product is
+    * the distance away from the line:
+    *
+    *    distance = |cross| / sqrt(len2)
+    */
+   cross = x * ly - y * lx;
+
+   /* If 'distance' is more than w the point is definitely outside the line:
+    *
+    *     distance >= w
+    *     |cross|  >= w * sqrt(len2)
+    *     cross^2  >= w^2 * len2:
+    */
+   if (cross*cross >= (w+expand)*(w+expand)*len2)
+      return 0; /* outside */
+
+   /* Now find the distance *along* the line; this comes from the dot product
+    * lx.x+ly.y. The actual distance (in pixels) is:
+    *
+    *   distance = dot / sqrt(len2)
+    */
+   dot = lx * x + ly * y;
+
+   /* The test for 'outside' is:
+    *
+    *    distance < 0 || distance > sqrt(len2)
+    *                 -> dot / sqrt(len2) > sqrt(len2)
+    *                 -> dot > len2
+    *
+    * But 'expand' is used for the filter width and needs to be handled too:
+    */
+   return dot > -expand && dot < len2+expand;
+}
+
+static int
+inside_line(const struct arg *arg, double x, double y)
+{
+   return line_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2, arg->width/2, 0);
+}
+
+static int
+check_line(const struct arg *arg, double x, double y)
+{
+   /* The end caps of the line must be checked too; it's not enough just to
+    * widen the line by FILTER_WIDTH; 'expand' exists for this purpose:
+    */
+   if (line_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2, arg->width/2,
+       FILTER_WIDTH))
+   {
+      /* Inside the line+filter; far enough inside that the filter isn't
+       * required?
+       */
+      if (arg->width > 2*FILTER_WIDTH &&
+          line_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2, arg->width/2,
+             -FILTER_WIDTH))
+         return INSIDE;
+
+      return 0;
+   }
+
+   return OUTSIDE;
+}
+
+static const struct
+{
+   const char    *name;
+   shape_fn_ptr   function[2/*fill,line*/][2];
+#  define         FN_INSIDE 0
+#  define         FN_CHECK 1
+} shape_defs[] =
+{
+   {  "square",
+      {  { inside_square_filled, check_square_filled },
+         { inside_square, check_square } }
+   },
+   {  "circle",
+      {  { inside_circle_filled, check_circle_filled },
+         { inside_circle, check_circle } }
+   },
+   {  "line",
+      {  { NULL, NULL },
+         { inside_line, check_line } }
+   }
+};
+
+#define shape_count ((sizeof shape_defs)/(sizeof shape_defs[0]))
+
+static shape_fn_ptr
+shape_of(const char *arg, double width, int f)
+{
+   unsigned int i;
+
+   for (i=0; i<shape_count; ++i) if (strcmp(shape_defs[i].name, arg) == 0)
+   {
+      shape_fn_ptr fn = shape_defs[i].function[width != 0][f];
+
+      if (fn != NULL)
+         return fn;
+
+      fprintf(stderr, "genpng: %s %s not supported\n",
+         width == 0 ? "filled" : "unfilled", arg);
+      exit(1);
+   }
+
+   fprintf(stderr, "genpng: %s: not a valid shape name\n", arg);
+   exit(1);
+}
+
+static void
+parse_arg(struct arg *arg, const char **argv/*7 arguments*/)
+{
+   /* shape ::= color width shape x1 y1 x2 y2 */
+   arg->color = color_of(argv[0]);
+   arg->width = width_of(argv[1]);
+   arg->inside_fn = shape_of(argv[2], arg->width, FN_INSIDE);
+   arg->check_fn = shape_of(argv[2], arg->width, FN_CHECK);
+   arg->x1 = coordinate_of(argv[3]);
+   arg->y1 = coordinate_of(argv[4]);
+   arg->x2 = coordinate_of(argv[5]);
+   arg->y2 = coordinate_of(argv[6]);
+}
+
+static png_uint_32
+read_wh(const char *name, const char *str)
+   /* read a PNG width or height */
+{
+   char *ep = NULL;
+   unsigned long ul = strtoul(str, &ep, 10);
+
+   if (ep != NULL && *ep == 0 && ul > 0 && ul <= 0x7fffffff)
+      return (png_uint_32)/*SAFE*/ul;
+
+   fprintf(stderr, "genpng: %s: invalid number %s\n", name, str);
+   exit(1);
+}
+
+static void
+pixel(png_uint_16p p, struct arg *args, int nargs, double x, double y)
+{
+   /* Fill in the pixel by checking each shape (args[nargs]) for effects on
+    * the corresponding sample:
+    */
+   double r=0, g=0, b=0, a=0;
+
+   while (--nargs >= 0 && a != 1)
+   {
+      /* NOTE: alpha_calc can return a value outside the range 0..1 with the
+       * bicubic filter.
+       */
+      const double alpha = alpha_calc(args+nargs, x, y) * (1-a);
+
+      r += alpha * args[nargs].color->red;
+      g += alpha * args[nargs].color->green;
+      b += alpha * args[nargs].color->blue;
+      a += alpha;
+   }
+
+   /* 'a' may be negative or greater than 1; if it is, negative clamp the
+    * pixel to 0 if >1 clamp r/g/b:
+    */
+   if (a > 0)
+   {
+      if (a > 1)
+      {
+         if (r > 1) r = 1;
+         if (g > 1) g = 1;
+         if (b > 1) b = 1;
+         a = 1;
+      }
+
+      /* And fill in the pixel: */
+      p[0] = (png_uint_16)/*SAFE*/round(r * 65535);
+      p[1] = (png_uint_16)/*SAFE*/round(g * 65535);
+      p[2] = (png_uint_16)/*SAFE*/round(b * 65535);
+      p[3] = (png_uint_16)/*SAFE*/round(a * 65535);
+   }
+
+   else
+      p[3] = p[2] = p[1] = p[0] = 0;
+}
+
+int
+main(int argc, const char **argv)
+{
+   int convert_to_8bit = 0;
+
+   /* There is one option: --8bit: */
+   if (argc > 1 && strcmp(argv[1], "--8bit") == 0)
+      --argc, ++argv, convert_to_8bit = 1;
+
+   if (argc >= 3)
+   {
+      png_uint_16p buffer;
+      int nshapes;
+      png_image image;
+#     define max_shapes 256
+      struct arg arg_list[max_shapes];
+
+      /* The libpng Simplified API write code requires a fully initialized
+       * structure.
+       */
+      memset(&image, 0, sizeof image);
+      image.version = PNG_IMAGE_VERSION;
+      image.opaque = NULL;
+      image.width = read_wh("width", argv[1]);
+      image.height = read_wh("height", argv[2]);
+      image.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+      image.flags = 0;
+      image.colormap_entries = 0;
+
+      /* Check the remainder of the arguments */
+      for (nshapes=0; 3+7*(nshapes+1) <= argc && nshapes < max_shapes;
+           ++nshapes)
+         parse_arg(arg_list+nshapes, argv+3+7*nshapes);
+
+      if (3+7*nshapes != argc)
+      {
+         fprintf(stderr, "genpng: %s: too many arguments\n", argv[3+7*nshapes]);
+         return 1;
+      }
+
+#if 1
+     /* TO do: determine whether this guard against overflow is necessary.
+      * This comment in png.h indicates that it should be safe: "libpng will
+      * refuse to process an image where such an overflow would occur", but
+      * I don't see where the image gets rejected when the buffer is too
+      * large before the malloc is attempted.
+      */
+      if (image.height > ((size_t)(-1))/(8*image.width)) {
+         fprintf(stderr, "genpng: image buffer would be too big");
+         return 1;
+      }
+#endif
+
+      /* Create the buffer: */
+      buffer = malloc(PNG_IMAGE_SIZE(image));
+
+      if (buffer != NULL)
+      {
+         png_uint_32 y;
+
+         /* Write each row... */
+         for (y=0; y<image.height; ++y)
+         {
+            png_uint_32 x;
+
+            /* Each pixel in each row: */
+            for (x=0; x<image.width; ++x)
+               pixel(buffer + 4*(x + y*image.width), arg_list, nshapes, x, y);
+         }
+
+         /* Write the result (to stdout) */
+         if (png_image_write_to_stdio(&image, stdout, convert_to_8bit,
+             buffer, 0/*row_stride*/, NULL/*colormap*/))
+         {
+            free(buffer);
+            return 0; /* success */
+         }
+
+         else
+            fprintf(stderr, "genpng: write stdout: %s\n", image.message);
+
+         free(buffer);
+      }
+
+      else
+         fprintf(stderr, "genpng: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+   }
+
+   else
+   {
+      /* Wrong number of arguments */
+      fprintf(stderr, "genpng: usage: genpng [--8bit] width height {shape}\n"
+         " Generate a transparent PNG in RGBA (truecolor+alpha) format\n"
+         " containing the given shape or shapes.  Shapes are defined:\n"
+         "\n"
+         "  shape ::= color width shape x1 y1 x2 y2\n"
+         "  color ::= black|white|red|green|yellow|blue\n"
+         "  color ::= brown|purple|pink|orange|gray|cyan\n"
+         "  width ::= filled|<number>\n"
+         "  shape ::= circle|square|line\n"
+         "  x1,x2 ::= <number>\n"
+         "  y1,y2 ::= <number>\n"
+         "\n"
+         " Numbers are floating point numbers describing points relative to\n"
+         " the top left of the output PNG as pixel coordinates.  The 'width'\n"
+         " parameter is either the width of the line (in output pixels) used\n"
+         " to draw the shape or 'filled' to indicate that the shape should\n"
+         " be filled with the color.\n"
+         "\n"
+         " Colors are interpreted loosely to give access to the eight full\n"
+         " intensity RGB values:\n"
+         "\n"
+         "  black, red, green, blue, yellow, cyan, purple, white,\n"
+         "\n"
+         " Cyan is full intensity blue+green; RGB(0,1,1), plus the following\n"
+         " lower intensity values:\n"
+         "\n"
+         "  brown:  red+orange:  RGB(0.5, 0.125, 0) (dark red+orange)\n"
+         "  pink:   red+white:   RGB(1.0, 0.5,   0.5)\n"
+         "  orange: red+yellow:  RGB(1.0, 0.5,   0)\n"
+         "  gray:   black+white: RGB(0.5, 0.5,   0.5)\n"
+         "\n"
+         " The RGB values are selected to make detection of aliasing errors\n"
+         " easy. The names are selected to make the description of errors\n"
+         " easy.\n"
+         "\n"
+         " The PNG is written to stdout, if --8bit is given a 32bpp RGBA sRGB\n"
+         " file is produced, otherwise a 64bpp RGBA linear encoded file is\n"
+         " written.\n");
+   }
+
+   return 1;
+}
+#endif /* SIMPLIFIED_WRITE && STDIO */
diff --git a/extern/libpng/contrib/tools/intgamma.sh b/extern/libpng/contrib/tools/intgamma.sh
new file mode 100755
index 0000000000..41c5d6dd27
--- /dev/null
+++ b/extern/libpng/contrib/tools/intgamma.sh
@@ -0,0 +1,110 @@
+#!/bin/sh
+#
+# intgamma.sh
+#
+# Last changed in libpng 1.6.0 [February 14, 2013]
+#
+# COPYRIGHT: Written by John Cunningham Bowler, 2013.
+# To the extent possible under law, the author has waived all copyright and
+# related or neighboring rights to this work.  This work is published from:
+# United States.
+#
+# Shell script to generate png.c 8-bit and 16-bit log tables (see the code in
+# png.c for details).
+#
+# This script uses the "bc" arbitrary precision calculator to calculate 32-bit
+# fixed point values of logarithms appropriate to finding the log of an 8-bit
+# (0..255) value and a similar table for the exponent calculation.
+#
+# "bc" must be on the path when the script is executed, and the math library
+# (-lm) must be available
+#
+# function to print out a list of numbers as integers; the function truncates
+# the integers which must be one-per-line
+function print(){
+   awk 'BEGIN{
+      str = ""
+   }
+   {
+      sub("\\.[0-9]*$", "")
+      if ($0 == "")
+         $0 = "0"
+
+      if (str == "")
+         t = "   " $0 "U"
+      else
+         t = str ", " $0 "U"
+
+      if (length(t) >= 80) {
+         print str ","
+         str = "   " $0 "U"
+      } else
+         str = t
+   }
+   END{
+      print str
+   }'
+}
+#
+# The logarithm table.
+cat <<END
+/* 8-bit log table: png_8bit_l2[128]
+ * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
+ * 255, so it's the base 2 logarithm of a normalized 8-bit floating point
+ * mantissa.  The numbers are 32-bit fractions.
+ */
+static const png_uint_32
+png_8bit_l2[128] =
+{
+END
+#
+bc -lqws <<END | print
+f=65536*65536/l(2)
+for (i=128;i<256;++i) { .5 - l(i/255)*f; }
+END
+echo '};'
+echo
+#
+# The exponent table.
+cat <<END
+/* The 'exp()' case must invert the above, taking a 20-bit fixed point
+ * logarithmic value and returning a 16 or 8-bit number as appropriate.  In
+ * each case only the low 16 bits are relevant - the fraction - since the
+ * integer bits (the top 4) simply determine a shift.
+ *
+ * The worst case is the 16-bit distinction between 65535 and 65534; this
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
+ * distinguish log2(65535/65534.5) - 10^-5 or 17 bits.  There is little chance
+ * of getting this accuracy in practice.
+ *
+ * To deal with this the following exp() function works out the exponent of the
+ * frational part of the logarithm by using an accurate 32-bit value from the
+ * top four fractional bits then multiplying in the remaining bits.
+ */
+static const png_uint_32
+png_32bit_exp[16] =
+{
+END
+#
+bc -lqws <<END | print
+f=l(2)/16
+for (i=0;i<16;++i) {
+   x = .5 + e(-i*f)*2^32;
+   if (x >= 2^32) x = 2^32-1;
+   x;
+}
+END
+echo '};'
+echo
+#
+# And the table of adjustment values.
+cat <<END
+/* Adjustment table; provided to explain the numbers in the code below. */
+#if 0
+END
+bc -lqws <<END | awk '{ printf "%5d %s\n", 12-NR, $0 }'
+for (i=11;i>=0;--i){
+   (1 - e(-(2^i)/65536*l(2))) * 2^(32-i)
+}
+END
+echo '#endif'
diff --git a/extern/libpng/contrib/tools/makesRGB.c b/extern/libpng/contrib/tools/makesRGB.c
new file mode 100644
index 0000000000..d0c0ca9314
--- /dev/null
+++ b/extern/libpng/contrib/tools/makesRGB.c
@@ -0,0 +1,430 @@
+/* makesRGB.c -- build sRGB-to-linear and linear-to-sRGB conversion tables
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2013.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Make a table to convert 8-bit sRGB encoding values into the closest 16-bit
+ * linear value.
+ *
+ * Make two tables to take a linear value scaled to 255*65535 and return an
+ * approximation to the 8-bit sRGB encoded value.  Calculate the error in these
+ * tables and display it.
+ */
+#define _C99_SOURCE 1
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+
+/* pngpriv.h includes the definition of 'PNG_sRGB_FROM_LINEAR' which is required
+ * to verify the actual code.
+ */
+#include "../../pngpriv.h"
+
+#include "sRGB.h"
+
+/* The tables are declared 'const' in pngpriv.h, so this redefines the tables to
+ * be used.
+ */
+#define png_sRGB_table sRGB_table
+#define png_sRGB_base sRGB_base
+#define png_sRGB_delta sRGB_delta
+
+static png_uint_16 png_sRGB_table[256];
+static png_uint_16 png_sRGB_base[512];
+static png_byte png_sRGB_delta[512];
+
+static const unsigned int max_input = 255*65535;
+
+double
+fsRGB(double l)
+{
+   return sRGB_from_linear(l/max_input);
+}
+
+double
+sRGB(unsigned int i)
+{
+   return fsRGB(i);
+}
+
+double
+finvsRGB(unsigned int i)
+{
+   return 65535 * linear_from_sRGB(i/255.);
+}
+
+png_uint_16
+invsRGB(unsigned int i)
+{
+   unsigned int x = nearbyint(finvsRGB(i));
+
+   if (x > 65535)
+   {
+      fprintf(stderr, "invsRGB(%u) overflows to %u\n", i, x);
+      exit(1);
+   }
+
+   return (png_uint_16)x;
+}
+
+int
+main(int argc, char **argv)
+{
+   unsigned int i, i16, ibase;
+   double min_error = 0;
+   double max_error = 0;
+   double min_error16 = 0;
+   double max_error16 = 0;
+   double adjust;
+   double adjust_lo = 0.4, adjust_hi = 0.6, adjust_mid = 0.5;
+   unsigned int ec_lo = 0, ec_hi = 0, ec_mid = 0;
+   unsigned int error_count = 0;
+   unsigned int error_count16 = 0;
+   int test_only = 0;
+
+   if (argc > 1)
+      test_only = strcmp("--test", argv[1]) == 0;
+
+   /* Initialize the encoding table first. */
+   for (i=0; i<256; ++i)
+   {
+      png_sRGB_table[i] = invsRGB(i);
+   }
+
+   /* Now work out the decoding tables (this is where the error comes in because
+    * there are 512 set points and 512 straight lines between them.)
+    */
+   for (;;)
+   {
+      if (ec_lo == 0)
+         adjust = adjust_lo;
+
+      else if (ec_hi == 0)
+         adjust = adjust_hi;
+
+      else if (ec_mid == 0)
+         adjust = adjust_mid;
+
+      else if (ec_mid < ec_hi)
+         adjust = (adjust_mid + adjust_hi)/2;
+
+      else if (ec_mid < ec_lo)
+         adjust = (adjust_mid + adjust_lo)/2;
+
+      else
+      {
+         fprintf(stderr, "not reached: %u .. %u .. %u\n", ec_lo, ec_mid, ec_hi);
+         exit(1);
+      }
+
+      /* Calculate the table using the current 'adjust' */
+      for (i=0; i<=511; ++i)
+      {
+         double lo = 255 * sRGB(i << 15);
+         double hi = 255 * sRGB((i+1) << 15);
+         unsigned int calc;
+
+         calc = nearbyint((lo+adjust) * 256);
+         if (calc > 65535)
+         {
+            fprintf(stderr, "table[%d][0]: overflow %08x (%d)\n", i, calc,
+               calc);
+            exit(1);
+         }
+         png_sRGB_base[i] = calc;
+
+         calc = nearbyint((hi-lo) * 32);
+         if (calc > 255)
+         {
+            fprintf(stderr, "table[%d][1]: overflow %08x (%d)\n", i, calc,
+               calc);
+            exit(1);
+         }
+         png_sRGB_delta[i] = calc;
+      }
+
+      /* Check the 16-bit linear values alone: */
+      error_count16 = 0;
+      for (i16=0; i16 <= 65535; ++i16)
+      {
+         unsigned int i = 255*i16;
+         unsigned int iexact = nearbyint(255*sRGB(i));
+         unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+         if (icalc != iexact)
+            ++error_count16;
+      }
+
+      /* Now try changing the adjustment. */
+      if (ec_lo == 0)
+         ec_lo = error_count16;
+
+      else if (ec_hi == 0)
+         ec_hi = error_count16;
+
+      else if (ec_mid == 0)
+      {
+         ec_mid = error_count16;
+         printf("/* initial error counts: %u .. %u .. %u */\n", ec_lo, ec_mid,
+            ec_hi);
+      }
+
+      else if (error_count16 < ec_mid)
+      {
+         printf("/* adjust (mid ): %f: %u -> %u */\n", adjust, ec_mid,
+            error_count16);
+         ec_mid = error_count16;
+         adjust_mid = adjust;
+      }
+
+      else if (adjust < adjust_mid && error_count16 < ec_lo)
+      {
+         printf("/* adjust (low ): %f: %u -> %u */\n", adjust, ec_lo,
+            error_count16);
+         ec_lo = error_count16;
+         adjust_lo = adjust;
+      }
+
+      else if (adjust > adjust_mid && error_count16 < ec_hi)
+      {
+         printf("/* adjust (high): %f: %u -> %u */\n", adjust, ec_hi,
+            error_count16);
+         ec_hi = error_count16;
+         adjust_hi = adjust;
+      }
+
+      else
+      {
+         adjust = adjust_mid;
+         printf("/* adjust: %f: %u */\n", adjust, ec_mid);
+         break;
+      }
+   }
+
+   /* For each entry in the table try to adjust it to minimize the error count
+    * in that entry.  Each entry corresponds to 128 input values.
+    */
+   for (ibase=0; ibase<65536; ibase+=128)
+   {
+      png_uint_16 base = png_sRGB_base[ibase >> 7], trybase = base, ob=base;
+      png_byte delta = png_sRGB_delta[ibase >> 7], trydelta = delta, od=delta;
+      unsigned int ecbase = 0, eco;
+
+      for (;;)
+      {
+         png_sRGB_base[ibase >> 7] = trybase;
+         png_sRGB_delta[ibase >> 7] = trydelta;
+
+         /* Check the 16-bit linear values alone: */
+         error_count16 = 0;
+         for (i16=ibase; i16 < ibase+128; ++i16)
+         {
+            unsigned int i = 255*i16;
+            unsigned int iexact = nearbyint(255*sRGB(i));
+            unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+            if (icalc != iexact)
+               ++error_count16;
+         }
+
+         if (error_count16 == 0)
+            break;
+
+         if (ecbase == 0)
+         {
+            eco = ecbase = error_count16;
+            ++trybase; /* First test */
+         }
+
+         else if (error_count16 < ecbase)
+         {
+            if (trybase > base)
+            {
+               base = trybase;
+               ++trybase;
+            }
+            else if (trybase < base)
+            {
+               base = trybase;
+               --trybase;
+            }
+            else if (trydelta > delta)
+            {
+               delta = trydelta;
+               ++trydelta;
+            }
+            else if (trydelta < delta)
+            {
+               delta = trydelta;
+               --trydelta;
+            }
+            else
+            {
+               fprintf(stderr, "makesRGB: impossible\n");
+               exit(1);
+            }
+            ecbase = error_count16;
+         }
+
+         else
+         {
+            if (trybase > base)
+               trybase = base-1;
+            else if (trybase < base)
+            {
+               trybase = base;
+               ++trydelta;
+            }
+            else if (trydelta > delta)
+               trydelta = delta-1;
+            else if (trydelta < delta)
+               break; /* end of tests */
+         }
+      }
+
+      png_sRGB_base[ibase >> 7] = base;
+      png_sRGB_delta[ibase >> 7] = delta;
+      if (base != ob || delta != od)
+      {
+         printf("/* table[%u]={%u,%u} -> {%u,%u} %u -> %u errors */\n",
+            ibase>>7, ob, od, base, delta, eco, ecbase);
+      }
+      else if (0)
+         printf("/* table[%u]={%u,%u} %u errors */\n", ibase>>7, ob, od,
+            ecbase);
+   }
+
+   /* Only do the full (slow) test at the end: */
+   min_error = -.4999;
+   max_error = .4999;
+   error_count = 0;
+
+   for (i=0; i <= max_input; ++i)
+   {
+      unsigned int iexact = nearbyint(255*sRGB(i));
+      unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+      if (icalc != iexact)
+      {
+         double err = 255*sRGB(i) - icalc;
+
+         if (err > (max_error+.001) || err < (min_error-.001))
+         {
+            printf(
+               "/* 0x%08x: exact: %3d, got: %3d [tables: %08x, %08x] (%f) */\n",
+               i, iexact, icalc, png_sRGB_base[i>>15],
+               png_sRGB_delta[i>>15], err);
+         }
+
+         ++error_count;
+         if (err > max_error)
+            max_error = err;
+         else if (err < min_error)
+            min_error = err;
+      }
+   }
+
+   /* Re-check the 16-bit cases too, including the warning if there is an error
+    * bigger than 1.
+    */
+   error_count16 = 0;
+   max_error16 = 0;
+   min_error16 = 0;
+   for (i16=0; i16 <= 65535; ++i16)
+   {
+      unsigned int i = 255*i16;
+      unsigned int iexact = nearbyint(255*sRGB(i));
+      unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+      if (icalc != iexact)
+      {
+         double err = 255*sRGB(i) - icalc;
+
+         ++error_count16;
+         if (err > max_error16)
+            max_error16 = err;
+         else if (err < min_error16)
+            min_error16 = err;
+
+         if (abs(icalc - iexact) > 1)
+            printf(
+               "/* 0x%04x: exact: %3d, got: %3d [tables: %08x, %08x] (%f) */\n",
+               i16, iexact, icalc, png_sRGB_base[i>>15],
+               png_sRGB_delta[i>>15], err);
+      }
+   }
+
+   /* Check the round trip for each 8-bit sRGB value. */
+   for (i16=0; i16 <= 255; ++i16)
+   {
+      unsigned int i = 255 * png_sRGB_table[i16];
+      unsigned int iexact = nearbyint(255*sRGB(i));
+      unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+      if (i16 != iexact)
+      {
+         fprintf(stderr, "8-bit rounding error: %d -> %d\n", i16, iexact);
+         exit(1);
+      }
+
+      if (icalc != i16)
+      {
+         double finv = finvsRGB(i16);
+
+         printf("/* 8-bit roundtrip error: %d -> %f -> %d(%f) */\n",
+            i16, finv, icalc, fsRGB(255*finv));
+      }
+   }
+
+
+   printf("/* error: %g - %g, %u (%g%%) of readings inexact */\n",
+      min_error, max_error, error_count, (100.*error_count)/max_input);
+   printf("/* 16-bit error: %g - %g, %u (%g%%) of readings inexact */\n",
+      min_error16, max_error16, error_count16, (100.*error_count16)/65535);
+
+   if (!test_only)
+   {
+      printf("const png_uint_16 png_sRGB_table[256] =\n{\n   ");
+      for (i=0; i<255; )
+      {
+         do
+         {
+            printf("%d,", png_sRGB_table[i++]);
+         }
+         while ((i & 0x7) != 0 && i<255);
+         if (i<255) printf("\n   ");
+      }
+      printf("%d\n};\n\n", png_sRGB_table[i]);
+
+
+      printf("const png_uint_16 png_sRGB_base[512] =\n{\n   ");
+      for (i=0; i<511; )
+      {
+         do
+         {
+            printf("%d,", png_sRGB_base[i++]);
+         }
+         while ((i & 0x7) != 0 && i<511);
+         if (i<511) printf("\n   ");
+      }
+      printf("%d\n};\n\n", png_sRGB_base[i]);
+
+      printf("const png_byte png_sRGB_delta[512] =\n{\n   ");
+      for (i=0; i<511; )
+      {
+         do
+         {
+            printf("%d,", png_sRGB_delta[i++]);
+         }
+         while ((i & 0xf) != 0 && i<511);
+         if (i<511) printf("\n   ");
+      }
+      printf("%d\n};\n\n", png_sRGB_delta[i]);
+   }
+
+   return 0;
+}
diff --git a/extern/libpng/contrib/tools/png-fix-itxt.c b/extern/libpng/contrib/tools/png-fix-itxt.c
new file mode 100644
index 0000000000..c7654c1136
--- /dev/null
+++ b/extern/libpng/contrib/tools/png-fix-itxt.c
@@ -0,0 +1,164 @@
+
+/* png-fix-itxt version 1.0.0
+ *
+ * Copyright 2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.18 [July 23, 2015]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Usage:
+ *
+ *     png-fix-itxt.exe < bad.png > good.png
+ *
+ * Fixes a PNG file written with libpng-1.6.0 or 1.6.1 that has one or more
+ * uncompressed iTXt chunks.  Assumes that the actual length is greater
+ * than or equal to the value in the length byte, and that the CRC is
+ * correct for the actual length.  This program hunts for the CRC and
+ * adjusts the length byte accordingly.  It is not an error to process a
+ * PNG file that has no iTXt chunks or one that has valid iTXt chunks;
+ * such files will simply be copied.
+ *
+ * Requires zlib (for crc32 and Z_NULL); build with
+ *
+ *     gcc -O -o png-fix-itxt png-fix-itxt.c -lz
+ *
+ * If you need to handle iTXt chunks larger than 500000 kbytes you must
+ * rebuild png-fix-itxt with a larger values of MAX_LENGTH (or a smaller value
+ * if you know you will never encounter such huge iTXt chunks).
+ */
+
+#include <stdio.h>
+#include <zlib.h>
+
+#define MAX_LENGTH 500000
+
+/* Read one character (inchar), also return octet (c), break if EOF */
+#define GETBREAK inchar=getchar(); \
+                 c=(inchar & 0xffU);\
+                 if (inchar != c) break
+int
+main(void)
+{
+   unsigned int i;
+   unsigned char buf[MAX_LENGTH];
+   unsigned long crc;
+   unsigned char c;
+   int inchar;
+
+/* Skip 8-byte signature */
+   for (i=8; i; i--)
+   {
+      GETBREAK;
+      putchar(c);
+   }
+
+if (inchar == c) /* !EOF */
+for (;;)
+ {
+   /* Read the length */
+   unsigned long length; /* must be 32 bits! */
+   GETBREAK; buf[0] = c; length  = c; length <<= 8;
+   GETBREAK; buf[1] = c; length += c; length <<= 8;
+   GETBREAK; buf[2] = c; length += c; length <<= 8;
+   GETBREAK; buf[3] = c; length += c;
+
+   /* Read the chunkname */
+   GETBREAK; buf[4] = c;
+   GETBREAK; buf[5] = c;
+   GETBREAK; buf[6] = c;
+   GETBREAK; buf[7] = c;
+
+
+   /* The iTXt chunk type expressed as integers is (105, 84, 88, 116) */
+   if (buf[4] == 105 && buf[5] == 84 && buf[6] == 88 && buf[7] == 116)
+   {
+      if (length >= MAX_LENGTH-12)
+         break;  /* To do: handle this more gracefully */
+
+      /* Initialize the CRC */
+      crc = crc32(0, Z_NULL, 0);
+
+      /* Copy the data bytes */
+      for (i=8; i < length + 12; i++)
+      {
+         GETBREAK; buf[i] = c;
+      }
+
+      if (inchar != c) /* EOF */
+         break;
+
+      /* Calculate the CRC */
+      crc = crc32(crc, buf+4, (uInt)length+4);
+
+      for (;;)
+      {
+        /* Check the CRC */
+        if (((crc >> 24) & 0xffU) == buf[length+8] &&
+            ((crc >> 16) & 0xffU) == buf[length+9] &&
+            ((crc >>  8) & 0xffU) == buf[length+10] &&
+            ((crc      ) & 0xffU) == buf[length+11])
+           break;
+
+        length++;
+
+        if (length >= MAX_LENGTH-12)
+           break;
+
+        GETBREAK;
+        buf[length+11] = c;
+
+        /* Update the CRC */
+        crc = crc32(crc, buf+7+length, 1);
+      }
+
+      if (inchar != c) /* EOF */
+         break;
+
+      /* Update length bytes */
+      buf[0] = (unsigned char)((length >> 24) & 0xffU);
+      buf[1] = (unsigned char)((length >> 16) & 0xffU);
+      buf[2] = (unsigned char)((length >>  8) & 0xffU);
+      buf[3] = (unsigned char)((length      ) & 0xffU);
+
+      /* Write the fixed iTXt chunk (length, name, data, crc) */
+      for (i=0; i<length+12; i++)
+         putchar(buf[i]);
+   }
+
+   else
+   {
+      if (inchar != c) /* EOF */
+         break;
+
+      /* Copy bytes that were already read (length and chunk name) */
+      for (i=0; i<8; i++)
+         putchar(buf[i]);
+
+      /* Copy data bytes and CRC */
+      for (i=8; i< length+12; i++)
+      {
+         GETBREAK;
+         putchar(c);
+      }
+
+      if (inchar != c) /* EOF */
+      {
+         break;
+      }
+
+   /* The IEND chunk type expressed as integers is (73, 69, 78, 68) */
+      if (buf[4] == 73 && buf[5] == 69 && buf[6] == 78 && buf[7] == 68)
+         break;
+   }
+
+   if (inchar != c) /* EOF */
+      break;
+
+   if (buf[4] == 73 && buf[5] == 69 && buf[6] == 78 && buf[7] == 68)
+     break;
+ }
+
+ return 0;
+}
diff --git a/extern/libpng/contrib/tools/pngcp.c b/extern/libpng/contrib/tools/pngcp.c
new file mode 100644
index 0000000000..16d4e7f4d1
--- /dev/null
+++ b/extern/libpng/contrib/tools/pngcp.c
@@ -0,0 +1,2453 @@
+/* pngcp.c
+ *
+ * Copyright (c) 2016 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.24 [August 4, 2016]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This is an example of copying a PNG without changes using the png_read_png
+ * and png_write_png interfaces.  A considerable number of options are provided
+ * to manipulate the compression of the PNG data and other compressed chunks.
+ *
+ * For a more extensive example that uses the transforms see
+ * contrib/libtests/pngimage.c in the libpng distribution.
+ */
+#include "pnglibconf.h" /* To find how libpng was configured. */
+
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+   /* WARNING:
+    *
+    * This test is here to allow POSIX.1b extensions to be used if enabled in
+    * the compile; specifically the code requires_POSIX_C_SOURCE support of
+    * 199309L or later to enable clock_gettime use.
+    *
+    * IF this causes problems THEN compile with a strict ANSI C compiler and let
+    * this code turn on the POSIX features that it minimally requires.
+    *
+    * IF this does not work there is probably a bug in your ANSI C compiler or
+    * your POSIX implementation.
+    */
+#  define _POSIX_C_SOURCE 199309L
+#else /* No timing support required */
+#  define _POSIX_SOURCE 1
+#endif
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+#include <stdio.h>
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+   /* READ_PNG and WRITE_PNG were not defined, so: */
+#  ifdef PNG_INFO_IMAGE_SUPPORTED
+#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#        define PNG_READ_PNG_SUPPORTED
+#     endif /* SEQUENTIAL_READ */
+#     ifdef PNG_WRITE_SUPPORTED
+#        define PNG_WRITE_PNG_SUPPORTED
+#     endif /* WRITE */
+#  endif /* INFO_IMAGE */
+#endif /* pre 1.7.0 */
+
+#if (defined(PNG_READ_PNG_SUPPORTED)) && (defined(PNG_WRITE_PNG_SUPPORTED))
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+#include <assert.h>
+
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include <zlib.h>
+
+#ifndef PNG_SETJMP_SUPPORTED
+#  include <setjmp.h> /* because png.h did *not* include this */
+#endif
+
+#ifdef __cplusplus
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+#ifdef __GNUC__
+   /* Many versions of GCC erroneously report that local variables unmodified
+    * within the scope of a setjmp may be clobbered.  This hacks round the
+    * problem (sometimes) without harming other compilers.
+    */
+#  define gv volatile
+#else
+#  define gv
+#endif
+
+/* 'CLOCK_PROCESS_CPUTIME_ID' is one of the clock timers for clock_gettime.  It
+ * need not be supported even when clock_gettime is available.  It returns the
+ * 'CPU' time the process has consumed.  'CPU' time is assumed to include time
+ * when the CPU is actually blocked by a pending cache fill but not time
+ * waiting for page faults.  The attempt is to get a measure of the actual time
+ * the implementation takes to read a PNG ignoring the potentially very large IO
+ * overhead.
+ */
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+#  include <time.h>   /* clock_gettime and associated definitions */
+#  ifndef CLOCK_PROCESS_CPUTIME_ID
+      /* Prevent inclusion of the spurious code: */
+#     undef PNG_PNGCP_TIMING_SUPPORTED
+#  endif
+#endif /* PNGCP_TIMING */
+
+/* So if the timing feature has been activated: */
+
+/* This structure is used to control the test of a single file. */
+typedef enum
+{
+   VERBOSE,        /* switches on all messages */
+   INFORMATION,
+   WARNINGS,       /* switches on warnings */
+   LIBPNG_WARNING,
+   APP_WARNING,
+   ERRORS,         /* just errors */
+   APP_FAIL,       /* continuable error - no need to longjmp */
+   LIBPNG_ERROR,   /* this and higher cause a longjmp */
+   LIBPNG_BUG,     /* erroneous behavior in libpng */
+   APP_ERROR,      /* such as out-of-memory in a callback */
+   QUIET,          /* no normal messages */
+   USER_ERROR,     /* such as file-not-found */
+   INTERNAL_ERROR
+} error_level;
+#define LEVEL_MASK      0xf   /* where the level is in 'options' */
+
+#define STRICT          0x010 /* Fail on warnings as well as errors */
+#define LOG             0x020 /* Log pass/fail to stdout */
+#define CONTINUE        0x040 /* Continue on APP_FAIL errors */
+#define SIZES           0x080 /* Report input and output sizes */
+#define SEARCH          0x100 /* Search IDAT compression options */
+#define NOWRITE         0x200 /* Do not write an output file */
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#  define IGNORE_INDEX  0x400 /* Ignore out of range palette indices (BAD!) */
+#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+#     define FIX_INDEX  0x800 /* 'Fix' out of range palette indices (OK) */
+#  endif /* GET_PALETTE_MAX */
+#endif /* CHECK_FOR_INVALID_INDEX */
+#define OPTION     0x80000000 /* Used for handling options */
+#define LIST       0x80000001 /* Used for handling options */
+
+/* Result masks apply to the result bits in the 'results' field below; these
+ * bits are simple 1U<<error_level.  A pass requires either nothing worse than
+ * warnings (--relaxes) or nothing worse than information (--strict)
+ */
+#define RESULT_STRICT(r)   (((r) & ~((1U<<WARNINGS)-1)) == 0)
+#define RESULT_RELAXED(r)  (((r) & ~((1U<<ERRORS)-1)) == 0)
+
+/* OPTION DEFINITIONS */
+static const char range_lo[] = "low";
+static const char range_hi[] = "high";
+static const char all[] = "all";
+#define RANGE(lo,hi) { range_lo, lo }, { range_hi, hi }
+typedef struct value_list
+{
+   const char *name;  /* the command line name of the value */
+   int         value; /* the actual value to use */
+}  value_list;
+
+static const value_list
+#ifdef PNG_SW_COMPRESS_png_level
+vl_compression[] =
+{
+   /* Overall compression control.  The order controls the search order for
+    * 'all'.  Since the search is for the smallest the order used is low memory
+    * then high speed.
+    */
+   { "low-memory",      PNG_COMPRESSION_LOW_MEMORY },
+   { "high-speed",      PNG_COMPRESSION_HIGH_SPEED },
+   { "high-read-speed", PNG_COMPRESSION_HIGH_READ_SPEED },
+   { "low",             PNG_COMPRESSION_LOW },
+   { "medium",          PNG_COMPRESSION_MEDIUM },
+   { "old",             PNG_COMPRESSION_COMPAT },
+   { "high",            PNG_COMPRESSION_HIGH },
+   { all, 0 }
+},
+#endif /* SW_COMPRESS_png_level */
+
+#if defined(PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED) ||\
+    defined(PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED)
+vl_strategy[] =
+{
+   /* This controls the order of search. */
+   { "huffman", Z_HUFFMAN_ONLY },
+   { "RLE", Z_RLE },
+   { "fixed", Z_FIXED }, /* the remainder do window searches */
+   { "filtered", Z_FILTERED },
+   { "default", Z_DEFAULT_STRATEGY },
+   { all, 0 }
+},
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+vl_windowBits_text[] =
+{
+   { "default", MAX_WBITS/*from zlib*/ },
+   { "minimum", 8 },
+   RANGE(8, MAX_WBITS/*from zlib*/),
+   { all, 0 }
+},
+#endif /* text compression */
+vl_level[] =
+{
+   { "default", Z_DEFAULT_COMPRESSION /* this is -1 */ },
+   { "none", Z_NO_COMPRESSION },
+   { "speed", Z_BEST_SPEED },
+   { "best", Z_BEST_COMPRESSION },
+   { "0", Z_NO_COMPRESSION },
+   RANGE(1, 9), /* this deliberately excludes '0' */
+   { all, 0 }
+},
+vl_memLevel[] =
+{
+   { "max", MAX_MEM_LEVEL }, /* zlib maximum */
+   { "1", 1 }, /* zlib minimum */
+   { "default", 8 }, /* zlib default */
+   { "2", 2 },
+   { "3", 3 },
+   { "4", 4 },
+   { "5", 5 }, /* for explicit testing */
+   RANGE(6, MAX_MEM_LEVEL/*zlib*/), /* exclude 5 and below: zlib bugs */
+   { all, 0 }
+},
+#endif /* WRITE_CUSTOMIZE_*COMPRESSION */
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+vl_filter[] =
+{
+   { all,      PNG_ALL_FILTERS   },
+   { "off",    PNG_NO_FILTERS    },
+   { "none",   PNG_FILTER_NONE   },
+   { "sub",    PNG_FILTER_SUB    },
+   { "up",     PNG_FILTER_UP     },
+   { "avg",    PNG_FILTER_AVG    },
+   { "paeth",  PNG_FILTER_PAETH  }
+},
+#endif /* WRITE_FILTER */
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+#  define PNGCP_TIME_READ  1
+#  define PNGCP_TIME_WRITE 2
+vl_time[] =
+{
+   { "both",  PNGCP_TIME_READ+PNGCP_TIME_WRITE },
+   { "off",   0 },
+   { "read",  PNGCP_TIME_READ },
+   { "write", PNGCP_TIME_WRITE }
+},
+#endif /* PNGCP_TIMING */
+vl_IDAT_size[] = /* for png_set_IDAT_size */
+{
+   { "default", 0x7FFFFFFF },
+   { "minimal", 1 },
+   RANGE(1, 0x7FFFFFFF)
+},
+#ifndef PNG_SW_IDAT_size
+   /* Pre 1.7 API: */
+#  define png_set_IDAT_size(p,v) png_set_compression_buffer_size(p, v)
+#endif /* !SW_IDAT_size */
+#define SL 8 /* stack limit in display, below */
+vl_log_depth[] = { { "on", 1 }, { "off", 0 }, RANGE(0, SL) },
+vl_on_off[] = { { "on", 1 }, { "off", 0 } };
+
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+static value_list
+vl_windowBits_IDAT[] =
+{
+   { "default", MAX_WBITS },
+   { "small", 9 },
+   RANGE(8, MAX_WBITS), /* modified by set_windowBits_hi */
+   { all, 0 }
+};
+#endif /* IDAT compression */
+
+typedef struct option
+{
+   const char       *name;         /* name of the option */
+   png_uint_32       opt;          /* an option, or OPTION or LIST */
+   png_byte          search;       /* Search on --search */
+   png_byte          value_count;  /* length of the list of values: */
+   const value_list *values;       /* values for OPTION or LIST */
+}  option;
+
+static const option options[] =
+{
+   /* struct display options, these are set when the command line is read */
+#  define S(n,v) { #n, v, 0, 2, vl_on_off },
+   S(verbose,  VERBOSE)
+   S(warnings, WARNINGS)
+   S(errors,   ERRORS)
+   S(quiet,    QUIET)
+   S(strict,   STRICT)
+   S(log,      LOG)
+   S(continue, CONTINUE)
+   S(sizes,    SIZES)
+   S(search,   SEARCH)
+   S(nowrite,  NOWRITE)
+#  ifdef IGNORE_INDEX
+      S(ignore-palette-index, IGNORE_INDEX)
+#  endif /* IGNORE_INDEX */
+#  ifdef FIX_INDEX
+      S(fix-palette-index, FIX_INDEX)
+#  endif /* FIX_INDEX */
+#  undef S
+
+   /* OPTION settings, these and LIST settings are read on demand */
+#  define VLNAME(name) vl_ ## name
+#  define VLSIZE(name) voidcast(png_byte,\
+                           (sizeof VLNAME(name))/(sizeof VLNAME(name)[0]))
+#  define VL(oname, name, type, search)\
+   { oname, type, search, VLSIZE(name), VLNAME(name) },
+#  define VLO(oname, name, search) VL(oname, name, OPTION, search)
+
+#  ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+#     define VLCIDAT(name) VLO(#name, name, 1/*search*/)
+#     ifdef PNG_SW_COMPRESS_level
+#        define VLCiCCP(name) VLO("ICC-profile-" #name, name, 0/*search*/)
+#     else
+#        define VLCiCCP(name)
+#     endif
+#  else
+#     define VLCIDAT(name)
+#     define VLCiCCP(name)
+#  endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+#  ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#     define VLCzTXt(name) VLO("text-" #name, name, 0/*search*/)
+#  else
+#     define VLCzTXt(name)
+#  endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+
+#  define VLC(name) VLCIDAT(name) VLCiCCP(name) VLCzTXt(name)
+
+#  ifdef PNG_SW_COMPRESS_png_level
+      /* The libpng compression level isn't searched because it justs sets the
+       * other things that are searched!
+       */
+      VLO("compression", compression, 0)
+      VLO("text-compression", compression, 0)
+      VLO("ICC-profile-compression", compression, 0)
+#  endif /* SW_COMPRESS_png_level */
+   VLC(strategy)
+   VLO("windowBits", windowBits_IDAT, 1)
+#  ifdef PNG_SW_COMPRESS_windowBits
+      VLO("ICC-profile-windowBits", windowBits_text/*sic*/, 0)
+#  endif
+   VLO("text-windowBits", windowBits_text, 0)
+   VLC(level)
+   VLC(memLevel)
+   VLO("IDAT-size", IDAT_size, 0)
+   VLO("log-depth", log_depth, 0)
+
+#  undef VLO
+
+   /* LIST settings */
+#  define VLL(name, search) VL(#name, name, LIST, search)
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   VLL(filter, 0)
+#endif /* WRITE_FILTER */
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+   VLL(time, 0)
+#endif /* PNGCP_TIMING */
+#  undef VLL
+#  undef VL
+};
+
+#ifdef __cplusplus
+   static const size_t option_count((sizeof options)/(sizeof options[0]));
+#else /* !__cplusplus */
+#  define option_count ((sizeof options)/(sizeof options[0]))
+#endif /* !__cplusplus */
+
+static const char *
+cts(int ct)
+{
+   switch (ct)
+   {
+      case PNG_COLOR_TYPE_PALETTE:     return "P";
+      case PNG_COLOR_TYPE_GRAY:        return "G";
+      case PNG_COLOR_TYPE_GRAY_ALPHA:  return "GA";
+      case PNG_COLOR_TYPE_RGB:         return "RGB";
+      case PNG_COLOR_TYPE_RGB_ALPHA:   return "RGBA";
+      default:                         return "INVALID";
+   }
+}
+
+struct display
+{
+   jmp_buf          error_return;      /* Where to go to on error */
+   unsigned int     errset;            /* error_return is set */
+
+   const char      *operation;         /* What is happening */
+   const char      *filename;          /* The name of the original file */
+   const char      *output_file;       /* The name of the output file */
+
+   /* Used on both read and write: */
+   FILE            *fp;
+
+   /* Used on a read, both the original read and when validating a written
+    * image.
+    */
+   png_alloc_size_t read_size;
+   png_structp      read_pp;
+   png_infop        ip;
+#  if PNG_LIBPNG_VER < 10700 && defined PNG_TEXT_SUPPORTED
+      png_textp     text_ptr; /* stash of text chunks */
+      int           num_text;
+      int           text_stashed;
+#  endif /* pre 1.7 */
+
+#  ifdef PNG_PNGCP_TIMING_SUPPORTED
+      struct timespec   read_time;
+      struct timespec   read_time_total;
+      struct timespec   write_time;
+      struct timespec   write_time_total;
+#  endif /* PNGCP_TIMING */
+
+   /* Used to write a new image (the original info_ptr is used) */
+#  define MAX_SIZE ((png_alloc_size_t)(-1))
+   png_alloc_size_t write_size;
+   png_alloc_size_t best_size;
+   png_structp      write_pp;
+
+   /* Base file information */
+   png_alloc_size_t size;
+   png_uint_32      w;
+   png_uint_32      h;
+   int              bpp;
+   png_byte         ct;
+   int              no_warnings;       /* Do not output libpng warnings */
+   int              min_windowBits;    /* The windowBits range is 8..8 */
+
+   /* Options handling */
+   png_uint_32      results;             /* A mask of errors seen */
+   png_uint_32      options;             /* See display_log below */
+   png_byte         entry[option_count]; /* The selected entry+1 of an option
+                                          * that appears on the command line, or
+                                          * 0 if it was not given. */
+   int              value[option_count]; /* Corresponding value */
+
+   /* Compression exhaustive testing */
+   /* Temporary variables used only while testing a single collection of
+    * settings:
+    */
+   unsigned int     csp;               /* next stack entry to use */
+   unsigned int     nsp;               /* highest active entry+1 found so far */
+
+   /* Values used while iterating through all the combinations of settings for a
+    * single file:
+    */
+   unsigned int     tsp;               /* nsp from the last run; this is the
+                                        * index+1 of the highest active entry on
+                                        * this run; this entry will be advanced.
+                                        */
+   int              opt_string_start;  /* Position in buffer for the first
+                                        * searched option; non-zero if earlier
+                                        * options were set on the command line.
+                                        */
+   struct stack
+   {
+      png_alloc_size_t best_size;      /* Best so far for this option */
+      png_alloc_size_t lo_size;
+      png_alloc_size_t hi_size;
+      int              lo, hi;         /* For binary chop of a range */
+      int              best_val;       /* Best value found so far */
+      int              opt_string_end; /* End of the option string in 'curr' */
+      png_byte         opt;            /* The option being tested */
+      png_byte         entry;          /* The next value entry to be tested */
+      png_byte         end;            /* This is the last entry */
+   }                stack[SL];         /* Stack of entries being tested */
+   char             curr[32*SL];       /* current options being tested */
+   char             best[32*SL];       /* best options */
+
+   char             namebuf[FILENAME_MAX]; /* output file name */
+};
+
+static void
+display_init(struct display *dp)
+   /* Call this only once right at the start to initialize the control
+    * structure, the (struct buffer) lists are maintained across calls - the
+    * memory is not freed.
+    */
+{
+   memset(dp, 0, sizeof *dp);
+   dp->operation = "internal error";
+   dp->filename = "command line";
+   dp->output_file = "no output file";
+   dp->options = WARNINGS; /* default to !verbose, !quiet */
+   dp->fp = NULL;
+   dp->read_pp = NULL;
+   dp->ip = NULL;
+   dp->write_pp = NULL;
+   dp->min_windowBits = -1; /* this is an OPTIND, so -1 won't match anything */
+#  if PNG_LIBPNG_VER < 10700 && defined PNG_TEXT_SUPPORTED
+      dp->text_ptr = NULL;
+      dp->num_text = 0;
+      dp->text_stashed = 0;
+#  endif /* pre 1.7 */
+}
+
+static void
+display_clean_read(struct display *dp)
+{
+   if (dp->read_pp != NULL)
+      png_destroy_read_struct(&dp->read_pp, NULL, NULL);
+
+   if (dp->fp != NULL)
+   {
+      FILE *fp = dp->fp;
+      dp->fp = NULL;
+      (void)fclose(fp);
+   }
+}
+
+static void
+display_clean_write(struct display *dp)
+{
+   if (dp->fp != NULL)
+   {
+      FILE *fp = dp->fp;
+      dp->fp = NULL;
+      (void)fclose(fp);
+   }
+
+   if (dp->write_pp != NULL)
+      png_destroy_write_struct(&dp->write_pp, dp->tsp > 0 ? NULL : &dp->ip);
+}
+
+static void
+display_clean(struct display *dp)
+{
+   display_clean_read(dp);
+   display_clean_write(dp);
+   dp->output_file = NULL;
+
+#  if PNG_LIBPNG_VER < 10700 && defined PNG_TEXT_SUPPORTED
+      /* This is actually created and used by the write code, but only
+       * once; it has to be retained for subsequent writes of the same file.
+       */
+      if (dp->text_stashed)
+      {
+         dp->text_stashed = 0;
+         dp->num_text = 0;
+         free(dp->text_ptr);
+         dp->text_ptr = NULL;
+      }
+#  endif /* pre 1.7 */
+
+   /* leave the filename for error detection */
+   dp->results = 0; /* reset for next time */
+}
+
+static void
+display_destroy(struct display *dp)
+{
+   /* Release any memory held in the display. */
+   display_clean(dp);
+}
+
+static struct display *
+get_dp(png_structp pp)
+   /* The display pointer is always stored in the png_struct error pointer */
+{
+   struct display *dp = (struct display*)png_get_error_ptr(pp);
+
+   if (dp == NULL)
+   {
+      fprintf(stderr, "pngcp: internal error (no display)\n");
+      exit(99); /* prevents a crash */
+   }
+
+   return dp;
+}
+
+/* error handling */
+#ifdef __GNUC__
+#  define VGATTR __attribute__((__format__ (__printf__,3,4)))
+   /* Required to quiet GNUC warnings when the compiler sees a stdarg function
+    * that calls one of the stdio v APIs.
+    */
+#else
+#  define VGATTR
+#endif
+static void VGATTR
+display_log(struct display *dp, error_level level, const char *fmt, ...)
+   /* 'level' is as above, fmt is a stdio style format string.  This routine
+    * does not return if level is above LIBPNG_WARNING
+    */
+{
+   dp->results |= 1U << level;
+
+   if (level > (error_level)(dp->options & LEVEL_MASK))
+   {
+      const char *lp;
+      va_list ap;
+
+      switch (level)
+      {
+         case INFORMATION:    lp = "information"; break;
+         case LIBPNG_WARNING: lp = "warning(libpng)"; break;
+         case APP_WARNING:    lp = "warning(pngcp)"; break;
+         case APP_FAIL:       lp = "error(continuable)"; break;
+         case LIBPNG_ERROR:   lp = "error(libpng)"; break;
+         case LIBPNG_BUG:     lp = "bug(libpng)"; break;
+         case APP_ERROR:      lp = "error(pngcp)"; break;
+         case USER_ERROR:     lp = "error(user)"; break;
+
+         case INTERNAL_ERROR: /* anything unexpected is an internal error: */
+         case VERBOSE: case WARNINGS: case ERRORS: case QUIET:
+         default:             lp = "bug(pngcp)"; break;
+      }
+
+      fprintf(stderr, "%s: %s: %s",
+         dp->filename != NULL ? dp->filename : "<stdin>", lp, dp->operation);
+
+      fprintf(stderr, ": ");
+
+      va_start(ap, fmt);
+      vfprintf(stderr, fmt, ap);
+      va_end(ap);
+
+      fputc('\n', stderr);
+   }
+   /* else do not output any message */
+
+   /* Errors cause this routine to exit to the fail code */
+   if (level > APP_FAIL || (level > ERRORS && !(dp->options & CONTINUE)))
+   {
+      if (dp->errset)
+         longjmp(dp->error_return, level);
+
+      else
+         exit(99);
+   }
+}
+
+#if PNG_LIBPNG_VER < 10700 && defined PNG_TEXT_SUPPORTED
+static void
+text_stash(struct display *dp)
+{
+   /* libpng 1.6 and earlier fixed a bug whereby text chunks were written
+    * multiple times by png_write_png; the issue was that png_write_png passed
+    * the same png_info to both png_write_info and png_write_end.  Rather than
+    * fixing it by recording the information in the png_struct, or by recording
+    * where to write the chunks, the fix made was to change the 'compression'
+    * field of the chunk to invalid values, rendering the png_info somewhat
+    * useless.
+    *
+    * The only fix for this given that we use the png_info more than once is to
+    * make a copy of the text chunks and png_set_text it each time.  This adds a
+    * text chunks, so they get replicated, but only the new set gets written
+    * each time.  This uses memory like crazy but there is no way to delete the
+    * useless chunks from the png_info.
+    *
+    * To make this slightly more efficient only the top level structure is
+    * copied; since the old strings are actually preserved (in 1.6 and earlier)
+    * this happens to work.
+    */
+   png_textp chunks = NULL;
+
+   dp->num_text = png_get_text(dp->write_pp, dp->ip, &chunks, NULL);
+
+   if (dp->num_text > 0)
+   {
+      dp->text_ptr = voidcast(png_textp, malloc(dp->num_text * sizeof *chunks));
+
+      if (dp->text_ptr == NULL)
+         display_log(dp, APP_ERROR, "text chunks: stash malloc failed");
+
+      else
+         memcpy(dp->text_ptr, chunks, dp->num_text * sizeof *chunks);
+   }
+
+   dp->text_stashed = 1; /* regardless of whether there are chunks or not */
+}
+
+#define text_stash(dp) if (!dp->text_stashed) text_stash(dp)
+
+static void
+text_restore(struct display *dp)
+{
+   /* libpng makes a copy, so this is fine: */
+   if (dp->text_ptr != NULL)
+      png_set_text(dp->write_pp, dp->ip, dp->text_ptr, dp->num_text);
+}
+
+#define text_restore(dp) if (dp->text_stashed) text_restore(dp)
+
+#else
+#define text_stash(dp) ((void)0)
+#define text_restore(dp) ((void)0)
+#endif /* pre 1.7 */
+
+/* OPTIONS:
+ *
+ * The command handles options of the forms:
+ *
+ *    --option
+ *       Turn an option on (Option)
+ *    --no-option
+ *       Turn an option off (Option)
+ *    --option=value
+ *       Set an option to a value (Value)
+ *    --option=val1,val2,val3
+ *       Set an option to a bitmask constructed from the values (List)
+ */
+static png_byte
+option_index(struct display *dp, const char *opt, size_t len)
+   /* Return the index (in options[]) of the given option, outputs an error if
+    * it does not exist.  Takes the name of the option and a length (number of
+    * characters in the name).
+    */
+{
+   png_byte j;
+
+   for (j=0; j<option_count; ++j)
+      if (strncmp(options[j].name, opt, len) == 0 && options[j].name[len] == 0)
+         return j;
+
+   /* If the setjmp buffer is set the code is asking for an option index; this
+    * is bad.  Otherwise this is the command line option parsing.
+    */
+   display_log(dp, dp->errset ? INTERNAL_ERROR : USER_ERROR,
+         "%.*s: unknown option", (int)/*SAFE*/len, opt);
+   abort(); /* NOT REACHED */
+}
+
+/* This works for an option name (no quotes): */
+#define OPTIND(dp, name) option_index(dp, #name, (sizeof #name)-1)
+
+static int
+get_option(struct display *dp, const char *opt, int *value)
+{
+   png_byte i = option_index(dp, opt, strlen(opt));
+
+   if (dp->entry[i]) /* option was set on command line */
+   {
+      *value = dp->value[i];
+      return 1;
+   }
+
+   else
+      return 0;
+}
+
+static int
+set_opt_string_(struct display *dp, unsigned int sp, png_byte opt,
+      const char *entry_name)
+   /* Add the appropriate option string to dp->curr. */
+{
+   int offset, add;
+
+   if (sp > 0)
+      offset = dp->stack[sp-1].opt_string_end;
+
+   else
+      offset = dp->opt_string_start;
+
+   if (entry_name == range_lo)
+      add = sprintf(dp->curr+offset, " --%s=%d", options[opt].name,
+            dp->value[opt]);
+
+   else
+      add = sprintf(dp->curr+offset, " --%s=%s", options[opt].name, entry_name);
+
+   if (add < 0)
+      display_log(dp, INTERNAL_ERROR, "sprintf failed");
+
+   assert(offset+add < (int)/*SAFE*/sizeof dp->curr);
+   return offset+add;
+}
+
+static void
+set_opt_string(struct display *dp, unsigned int sp)
+   /* Add the appropriate option string to dp->curr. */
+{
+   dp->stack[sp].opt_string_end = set_opt_string_(dp, sp, dp->stack[sp].opt, 
+      options[dp->stack[sp].opt].values[dp->stack[sp].entry].name);
+}
+
+static void
+record_opt(struct display *dp, png_byte opt, const char *entry_name)
+   /* Record this option in dp->curr; called for an option not being searched,
+    * the caller passes in the name of the value, or range_lo to use the
+    * numerical value.
+    */
+{
+   unsigned int sp = dp->csp; /* stack entry of next searched option */
+
+   if (sp >= dp->tsp)
+   {
+      /* At top of stack; add the opt string for this entry to the previous
+       * searched entry or the start of the dp->curr buffer if there is nothing
+       * on the stack yet (sp == 0).
+       */
+      int offset = set_opt_string_(dp, sp, opt, entry_name);
+
+      if (sp > 0)
+         dp->stack[sp-1].opt_string_end = offset;
+
+      else
+         dp->opt_string_start = offset;
+   }
+
+   /* else do nothing: option already recorded */
+}
+
+static int
+opt_list_end(struct display *dp, png_byte opt, png_byte entry)
+{
+   if (options[opt].values[entry].name == range_lo)
+      return entry+1U >= options[opt].value_count /* missing range_hi */ ||
+         options[opt].values[entry+1U].name != range_hi /* likewise */ ||
+         options[opt].values[entry+1U].value <= dp->value[opt] /* range end */;
+
+   else
+      return entry+1U >= options[opt].value_count /* missing 'all' */ ||
+         options[opt].values[entry+1U].name == all /* last entry */;
+}
+
+static void
+push_opt(struct display *dp, unsigned int sp, png_byte opt, int search)
+   /* Push a new option onto the stack, initializing the new stack entry
+    * appropriately; this does all the work of next_opt (setting end/nsp) for
+    * the first entry in the list.
+    */
+{
+   png_byte entry;
+   const char *entry_name;
+
+   assert(sp == dp->tsp && sp < SL);
+
+   /* The starting entry is entry 0 unless there is a range in which case it is
+    * the entry corresponding to range_lo:
+    */
+   entry = options[opt].value_count;
+   assert(entry > 0U);
+
+   do
+   {
+      entry_name = options[opt].values[--entry].name;
+      if (entry_name == range_lo)
+         break;
+   }
+   while (entry > 0U);
+
+   dp->tsp = sp+1U;
+   dp->stack[sp].best_size =
+      dp->stack[sp].lo_size =
+      dp->stack[sp].hi_size = MAX_SIZE;
+
+   if (search && entry_name == range_lo) /* search this range */
+   {
+      dp->stack[sp].lo = options[opt].values[entry].value;
+      /* check for a mal-formed RANGE above: */
+      assert(entry+1 < options[opt].value_count &&
+             options[opt].values[entry+1].name == range_hi);
+      dp->stack[sp].hi = options[opt].values[entry+1].value;
+   }
+
+   else
+   {
+      /* next_opt will just iterate over the range. */
+      dp->stack[sp].lo = INT_MAX;
+      dp->stack[sp].hi = INT_MIN; /* Prevent range chop */
+   }
+
+   dp->stack[sp].opt = opt;
+   dp->stack[sp].entry = entry;
+   dp->stack[sp].best_val = dp->value[opt] = options[opt].values[entry].value;
+
+   set_opt_string(dp, sp);
+
+   /* This works for the search case too; if the range has only one entry 'end'
+    * will be marked here.
+    */
+   if (opt_list_end(dp, opt, entry))
+   {
+      dp->stack[sp].end = 1;
+      /* Skip the warning if pngcp did this itself.  See the code in
+       * set_windowBits_hi.
+       */
+      if (opt != dp->min_windowBits)
+         display_log(dp, APP_WARNING, "%s: only testing one value",
+               options[opt].name);
+   }
+
+   else
+   {
+      dp->stack[sp].end = 0;
+      dp->nsp = dp->tsp;
+   }
+
+   /* Do a lazy cache of the text chunks for libpng 1.6 and earlier; this is
+    * because they can only be written once(!) so if we are going to re-use the
+    * png_info we need a copy.
+    */
+   text_stash(dp);
+}
+
+static void
+next_opt(struct display *dp, unsigned int sp)
+   /* Return the next value for this option.  When called 'sp' is expected to be
+    * the topmost stack entry - only the topmost entry changes each time round -
+    * and there must be a valid entry to return.  next_opt will set dp->nsp to
+    * sp+1 if more entries are available, otherwise it will not change it and
+    * set dp->stack[s].end to true.
+    */
+{
+   int search = 0;
+   png_byte entry, opt;
+   const char *entry_name;
+
+   /* dp->stack[sp] must be the top stack entry and it must be active: */
+   assert(sp+1U == dp->tsp && !dp->stack[sp].end);
+
+   opt = dp->stack[sp].opt;
+   entry = dp->stack[sp].entry;
+   assert(entry+1U < options[opt].value_count);
+   entry_name = options[opt].values[entry].name;
+   assert(entry_name != NULL);
+
+   /* For ranges increment the value but don't change the entry, for all other
+    * cases move to the next entry and load its value:
+    */
+   if (entry_name == range_lo) /* a range */
+   {
+      /* A range can be iterated over or searched.  The default iteration option
+       * is indicated by hi < lo on the stack, otherwise the range being search
+       * is [lo..hi] (inclusive).
+       */
+      if (dp->stack[sp].lo > dp->stack[sp].hi)
+         dp->value[opt]++;
+
+      else
+      {
+         /* This is the best size found for this option value: */
+         png_alloc_size_t best_size = dp->stack[sp].best_size;
+         int lo = dp->stack[sp].lo;
+         int hi = dp->stack[sp].hi;
+         int val = dp->value[opt];
+
+         search = 1; /* end is determined here */
+         assert(best_size < MAX_SIZE);
+
+         if (val == lo)
+         {
+            /* Finding the best for the low end of the range: */
+            dp->stack[sp].lo_size = best_size;
+            assert(hi > val);
+
+            if (hi == val+1) /* only 2 entries */
+               dp->stack[sp].end = 1;
+
+            val = hi;
+         }
+
+         else if (val == hi)
+         {
+            dp->stack[sp].hi_size = best_size;
+            assert(val > lo+1); /* else 'end' set above */
+
+            if (val == lo+2) /* only three entries to test */
+               dp->stack[sp].end = 1;
+
+            val = (lo + val)/2;
+         }
+
+         else
+         {
+            png_alloc_size_t lo_size = dp->stack[sp].lo_size;
+            png_alloc_size_t hi_size = dp->stack[sp].hi_size;
+
+            /* lo and hi should have been tested. */
+            assert(lo_size < MAX_SIZE && hi_size < MAX_SIZE);
+
+            /* These cases arise with the 'probe' handling below when there is a
+             * dip or peak in the size curve.
+             */
+            if (val < lo) /* probing a new lo */
+            {
+               /* Swap lo and val: */
+               dp->stack[sp].lo = val;
+               dp->stack[sp].lo_size = best_size;
+               val = lo;
+               best_size = lo_size;
+               lo = dp->stack[sp].lo;
+               lo_size = dp->stack[sp].lo_size;
+            }
+
+            else if (val > hi) /* probing a new hi */
+            {
+               /* Swap hi and val: */
+               dp->stack[sp].hi = val;
+               dp->stack[sp].hi_size = best_size;
+               val = hi;
+               best_size = hi_size;
+               hi = dp->stack[sp].hi;
+               hi_size = dp->stack[sp].hi_size;
+            }
+
+            /* The following should be true or something got messed up above. */
+            assert(lo < val && val < hi);
+
+            /* If there are only four entries (lo, val, hi plus one more) just
+             * test the remaining entry.
+             */
+            if (hi == lo+3)
+            {
+               /* Because of the 'probe' code val can either be lo+1 or hi-1; we
+                * need to test the other.
+                */
+               val = lo + ((val == lo+1) ? 2 : 1);
+               assert(lo < val && val < hi);
+               dp->stack[sp].end = 1;
+            }
+
+            else
+            {
+               /* There are at least 2 entries still untested between lo and hi,
+                * i.e. hi >= lo+4.  'val' is the midpoint +/- 0.5
+                *
+                * Separate out the four easy cases when lo..val..hi are
+                * monotonically decreased or (more weird) increasing:
+                */
+               assert(hi > lo+3);
+
+               if (lo_size <= best_size && best_size <= hi_size)
+               {
+                  /* Select the low range; testing this first favours the low
+                   * range over the high range when everything comes out equal.
+                   * Because of the probing 'val' may be lo+1.  In that case end
+                   * the search and set 'val' to lo+2.
+                   */
+                  if (val == lo+1)
+                  {
+                     ++val;
+                     dp->stack[sp].end = 1;
+                  }
+
+                  else
+                  {
+                     dp->stack[sp].hi = hi = val;
+                     dp->stack[sp].hi_size = best_size;
+                     val = (lo + val) / 2;
+                  }
+               }
+
+               else if (lo_size >= best_size && best_size >= hi_size)
+               {
+                  /* Monotonically decreasing size; this is the expected case.
+                   * Select the high end of the range.  As above, val may be
+                   * hi-1.
+                   */
+                  if (val == hi-1)
+                  {
+                     --val;
+                     dp->stack[sp].end = 1;
+                  }
+
+                  else
+                  {
+                     dp->stack[sp].lo = lo = val;
+                     dp->stack[sp].lo_size = best_size;
+                     val = (val + hi) / 2;
+                  }
+               }
+
+               /* If both those tests failed 'best_size' is either greater than
+                * or less than both lo_size and hi_size.  There is a peak or dip
+                * in the curve of sizes from lo to hi and val is on the peak or
+                * dip.
+                *
+                * Because the ranges being searched as so small (level is 1..9,
+                * windowBits 8..15, memLevel 1..9) there will only be at most
+                * three untested values between lo..val and val..hi, so solve
+                * the problem by probing down from hi or up from lo, whichever
+                * is the higher.
+                *
+                * This is the place where 'val' is set to outside the range
+                * lo..hi, described as 'probing', though maybe 'narrowing' would
+                * be more accurate.
+                */
+               else if (lo_size <= hi_size) /* down from hi */
+               {
+                  dp->stack[sp].hi = val;
+                  dp->stack[sp].hi_size = best_size;
+                  val = --hi;
+               }
+
+               else /* up from low */
+               {
+                  dp->stack[sp].lo = val;
+                  dp->stack[sp].lo_size = best_size;
+                  val = ++lo;
+               }
+
+               /* lo and hi are still the true range limits, check for the end
+                * condition.
+                */
+               assert(hi > lo+1);
+               if (hi <= lo+2)
+                  dp->stack[sp].end = 1;
+            }
+         }
+
+         assert(val != dp->stack[sp].best_val); /* should be a new value */
+         dp->value[opt] = val;
+         dp->stack[sp].best_size = MAX_SIZE;
+      }
+   }
+
+   else
+   {
+      /* Increment 'entry' */
+      dp->value[opt] = options[opt].values[++entry].value;
+      dp->stack[sp].entry = entry;
+   }
+
+   set_opt_string(dp, sp);
+
+   if (!search && opt_list_end(dp, opt, entry)) /* end of list */
+      dp->stack[sp].end = 1;
+
+   else if (!dp->stack[sp].end) /* still active after all these tests */
+      dp->nsp = dp->tsp;
+}
+
+static int
+compare_option(const struct display *dp, unsigned int sp)
+{
+   int opt = dp->stack[sp].opt;
+
+   /* If the best so far is numerically less than the current value the
+    * current set of options is invariably worse.
+    */
+   if (dp->stack[sp].best_val < dp->value[opt])
+      return -1;
+
+   /* Lists of options are searched out of numerical order (currently only
+    * strategy), so only return +1 here when a range is being searched.
+    */
+   else if (dp->stack[sp].best_val > dp->value[opt])
+   {
+      if (dp->stack[sp].lo <= dp->stack[sp].hi /*searching*/)
+         return 1;
+
+      else
+         return -1;
+   }
+
+   else
+      return 0; /* match; current value is the best one */
+}
+
+static int
+advance_opt(struct display *dp, png_byte opt, int search)
+{
+   unsigned int sp = dp->csp++; /* my stack entry */
+
+   assert(sp >= dp->nsp); /* nsp starts off zero */
+
+   /* If the entry was active in the previous run dp->stack[sp] is already
+    * set up and dp->tsp will be greater than sp, otherwise a new entry
+    * needs to be created.
+    *
+    * dp->nsp is handled this way:
+    *
+    * 1) When an option is pushed onto the stack dp->nsp and dp->tsp are
+    *    both set (by push_opt) to the next stack entry *unless* there is
+    *    only one entry in the new list, in which case dp->stack[sp].end
+    *    is set.
+    *
+    * 2) For the top stack entry next_opt is called.  The entry must be
+    *    active (dp->stack[sp].end is not set) and either 'nsp' or 'end'
+    *    will be updated as appropriate.
+    *
+    * 3) For lower stack entries nsp is set unless the stack entry is
+    *    already at the end.  This means that when all the higher entries
+    *    are popped this entry will be too.
+    */
+   if (sp >= dp->tsp)
+   {
+      push_opt(dp, sp, opt, search); /* This sets tsp to sp+1 */
+      return 1; /* initialized */
+   }
+
+   else
+   {
+      int ret = 0; /* unchanged */
+
+      /* An option that is already on the stack; update best_size and best_val
+       * if appropriate.  On the first run there are no previous values and
+       * dp->write_size will be MAX_SIZE, however on the first run dp->tsp
+       * starts off as 0.
+       */
+      assert(dp->write_size > 0U && dp->write_size < MAX_SIZE);
+
+      if (dp->stack[sp].best_size > dp->write_size ||
+          (dp->stack[sp].best_size == dp->write_size &&
+           compare_option(dp, sp) > 0))
+      {
+         dp->stack[sp].best_size = dp->write_size;
+         dp->stack[sp].best_val = dp->value[opt];
+      }
+
+      if (sp+1U >= dp->tsp)
+      {
+         next_opt(dp, sp);
+         ret = 1; /* advanced */
+      }
+
+      else if (!dp->stack[sp].end) /* Active, not at top of stack */
+         dp->nsp = sp+1U;
+
+      return ret; /* advanced || unchanged */
+   }
+}
+
+static int
+getallopts_(struct display *dp, png_byte opt, int *value, int record)
+   /* Like getop but iterate over all the values if the option was set to "all".
+    */
+{
+   if (dp->entry[opt]) /* option was set on command line */
+   {
+      /* Simple, single value, entries don't have a stack frame and have a fixed
+       * value (it doesn't change once set on the command line).  Otherwise the
+       * value (entry) selected from the command line is 'all':
+       */
+      const char *entry_name = options[opt].values[dp->entry[opt]-1].name;
+
+      if (entry_name == all)
+         (void)advance_opt(dp, opt, 0/*do not search; iterate*/);
+
+      else if (record)
+         record_opt(dp, opt, entry_name);
+
+      *value = dp->value[opt];
+      return 1; /* set */
+   }
+
+   else
+      return 0; /* not set */
+}
+
+static int
+getallopts(struct display *dp, const char *opt_str, int *value)
+{
+   return getallopts_(dp, option_index(dp, opt_str, strlen(opt_str)), value, 0);
+}
+
+static int
+getsearchopts(struct display *dp, const char *opt_str, int *value)
+   /* As above except that if the option was not set try a search */
+{
+   png_byte istrat;
+   png_byte opt = option_index(dp, opt_str, strlen(opt_str));
+   int record = options[opt].search;
+   const char *entry_name;
+
+   /* If it was set on the command line honour the setting, including 'all'
+    * which will override the built in search:
+    */
+   if (getallopts_(dp, opt, value, record))
+      return 1;
+
+   else if (!record) /* not a search option */
+      return 0; /* unset and not searched */
+
+   /* Otherwise decide what to do here. */
+   istrat = OPTIND(dp, strategy);
+   entry_name = range_lo; /* record the value, not the name */
+
+   if (opt == istrat) /* search all strategies */
+      (void)advance_opt(dp, opt, 0/*iterate*/), record=0;
+
+   else if (opt == OPTIND(dp, level))
+   {
+      /* Both RLE and HUFFMAN don't benefit from level increases */
+      if (dp->value[istrat] == Z_RLE || dp->value[istrat] == Z_HUFFMAN_ONLY)
+         dp->value[opt] = 1;
+
+      else /* fixed, filtered or default */
+         (void)advance_opt(dp, opt, 1/*search*/), record=0;
+   }
+
+   else if (opt == OPTIND(dp, windowBits))
+   {
+      /* Changing windowBits for strategies that do not search the window is
+       * pointless.  Huffman-only does not search, RLE only searches backwards
+       * one byte, so given that the maximum string length is 258, a windowBits
+       * of 9 is always sufficient.
+       */
+      if (dp->value[istrat] == Z_HUFFMAN_ONLY)
+         dp->value[opt] = 8;
+
+      else if (dp->value[istrat] == Z_RLE)
+         dp->value[opt] = 9;
+
+      else /* fixed, filtered or default */
+         (void)advance_opt(dp, opt, 1/*search*/), record=0;
+   }
+
+   else if (opt == OPTIND(dp, memLevel))
+   {
+#     if 0
+         (void)advance_opt(dp, opt, 0/*all*/), record=0;
+#     else
+         dp->value[opt] = MAX_MEM_LEVEL;
+#     endif
+   }
+
+   else /* something else */
+      assert(0=="reached");
+
+   if (record)
+      record_opt(dp, opt, entry_name);
+
+   /* One of the above searched options: */
+   *value = dp->value[opt];
+   return 1;
+}
+
+static int
+find_val(struct display *dp, png_byte opt, const char *str, size_t len)
+   /* Like option_index but sets (index+i) of the entry in options[opt] that
+    * matches str[0..len-1] into dp->entry[opt] as well as returning the actual
+    * value.
+    */
+{
+   int rlo = INT_MAX, rhi = INT_MIN;
+   png_byte j, irange = 0;
+
+   for (j=1U; j<=options[opt].value_count; ++j)
+   {
+      if (strncmp(options[opt].values[j-1U].name, str, len) == 0 &&
+          options[opt].values[j-1U].name[len] == 0)
+      {
+         dp->entry[opt] = j;
+         return options[opt].values[j-1U].value;
+      }
+      else if (options[opt].values[j-1U].name == range_lo)
+         rlo = options[opt].values[j-1U].value, irange = j;
+      else if (options[opt].values[j-1U].name == range_hi)
+         rhi = options[opt].values[j-1U].value;
+   }
+
+   /* No match on the name, but there may be a range. */
+   if (irange > 0)
+   {
+      char *ep = NULL;
+      long l = strtol(str, &ep, 0);
+
+      if (ep == str+len && l >= rlo && l <= rhi)
+      {
+         dp->entry[opt] = irange; /* range_lo */
+         return (int)/*SAFE*/l;
+      }
+   }
+
+   display_log(dp, dp->errset ? INTERNAL_ERROR : USER_ERROR,
+         "%s: unknown value setting '%.*s'", options[opt].name,
+         (int)/*SAFE*/len, str);
+   abort(); /* NOT REACHED */
+}
+
+static int
+opt_check(struct display *dp, const char *arg)
+{
+   assert(dp->errset == 0);
+
+   if (arg != NULL && arg[0] == '-' && arg[1] == '-')
+   {
+      int i = 0, negate = (strncmp(arg+2, "no-", 3) == 0), val;
+      png_byte j;
+
+      if (negate)
+         arg += 5; /* --no- */
+
+      else
+         arg += 2; /* -- */
+
+      /* Find the length (expect arg\0 or arg=) */
+      while (arg[i] != 0 && arg[i] != '=') ++i;
+
+      /* So arg[0..i-1] is the argument name, this does not return if this isn't
+       * a valid option name.
+       */
+      j = option_index(dp, arg, i);
+
+      /* It matcheth an option; check the remainder. */
+      if (arg[i] == 0) /* no specified value, use the default */
+      {
+         val = options[j].values[negate].value;
+         dp->entry[j] = (png_byte)/*SAFE*/(negate + 1U);
+      }
+
+      else
+      {
+         const char *list = arg + (i+1);
+
+         /* Expect a single value here unless this is a list, in which case
+          * multiple values are combined.
+          */
+         if (options[j].opt != LIST)
+         {
+            /* find_val sets 'dp->entry[j]' to a non-zero value: */
+            val = find_val(dp, j, list, strlen(list));
+
+            if (negate)
+            {
+               if (options[j].opt < OPTION)
+                  val = !val;
+
+               else
+               {
+                  display_log(dp, USER_ERROR,
+                        "%.*s: option=arg cannot be negated", i, arg);
+                  abort(); /* NOT REACHED */
+               }
+            }
+         }
+
+         else /* multiple options separated by ',' characters */
+         {
+            /* --no-option negates list values from the default, which should
+             * therefore be 'all'.  Notice that if the option list is empty in
+             * this case nothing will be removed and therefore --no-option= is
+             * the same as --option.
+             */
+            if (negate)
+               val = options[j].values[0].value;
+
+            else
+               val = 0;
+
+            while (*list != 0) /* allows option= which sets 0 */
+            {
+               /* A value is terminated by the end of the list or a ','
+                * character.
+                */
+               int v, iv;
+
+               iv = 0; /* an index into 'list' */
+               while (list[++iv] != 0 && list[iv] != ',') {}
+
+               v = find_val(dp, j, list, iv);
+
+               if (negate)
+                  val &= ~v;
+
+               else
+                  val |= v;
+
+               list += iv;
+               if (*list != 0)
+                  ++list; /* skip the ',' */
+            }
+         }
+      }
+
+      /* 'val' is the new value, store it for use later and debugging: */
+      dp->value[j] = val;
+
+      if (options[j].opt < LEVEL_MASK)
+      {
+         /* The handling for error levels is to set the level. */
+         if (val) /* Set this level */
+            dp->options = (dp->options & ~LEVEL_MASK) | options[j].opt;
+
+         else
+            display_log(dp, USER_ERROR,
+      "%.*s: messages cannot be turned off individually; set a message level",
+                  i, arg);
+      }
+
+      else if (options[j].opt < OPTION)
+      {
+         if (val)
+            dp->options |= options[j].opt;
+
+         else
+            dp->options &= ~options[j].opt;
+      }
+
+      return 1; /* this is an option */
+   }
+
+   else
+      return 0; /* not an option */
+}
+
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+static void
+set_timer(struct display *dp, struct timespec *timer)
+{
+   /* Do the timing using clock_gettime and the per-process timer. */
+   if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, timer))
+   {
+      display_log(dp, APP_ERROR,
+            "CLOCK_PROCESS_CPUTIME_ID: %s: timing disabled\n", strerror(errno));
+      dp->value[OPTIND(dp,time)] = 0; /* i.e. off */
+   }
+}
+
+static void
+start_timer(struct display *dp, int what)
+{
+   if ((dp->value[OPTIND(dp,time)] & what) != 0)
+      set_timer(dp, what == PNGCP_TIME_READ ? &dp->read_time : &dp->write_time);
+}
+
+static void
+end_timer(struct display *dp, int what)
+{
+   if ((dp->value[OPTIND(dp,time)] & what) != 0)
+   {
+      struct timespec t, tmp;
+
+      set_timer(dp, &t);
+
+      if (what == PNGCP_TIME_READ)
+         tmp = dp->read_time;
+
+      else
+         tmp = dp->write_time;
+
+      t.tv_sec -= tmp.tv_sec;
+      t.tv_nsec -= tmp.tv_nsec;
+
+      if (t.tv_nsec < 0)
+      {
+         --(t.tv_sec);
+         t.tv_nsec += 1000000000L;
+      }
+
+      if (what == PNGCP_TIME_READ)
+         dp->read_time = t, tmp = dp->read_time_total;
+
+      else
+         dp->write_time = t, tmp = dp->write_time_total;
+
+      tmp.tv_sec += t.tv_sec;
+      tmp.tv_nsec += t.tv_nsec;
+
+      if (tmp.tv_nsec >= 1000000000L)
+      {
+         ++(tmp.tv_sec);
+         tmp.tv_nsec -= 1000000000L;
+      }
+
+      if (what == PNGCP_TIME_READ)
+         dp->read_time_total = tmp;
+
+      else
+         dp->write_time_total = tmp;
+   }
+}
+
+static void
+print_time(const char *what, struct timespec t)
+{
+   printf("%s %.2lu.%.9ld", what, (unsigned long)t.tv_sec, t.tv_nsec);
+}
+#else /* !PNGCP_TIMING */
+#define start_timer(dp, what) ((void)0)
+#define end_timer(dp, what) ((void)0)
+#endif /* !PNGCP_TIMING */
+
+/* The following is used in main to verify that the final argument is a
+ * directory:
+ */
+static int
+checkdir(const char *pathname)
+{
+   struct stat buf;
+   return stat(pathname, &buf) == 0 && S_ISDIR(buf.st_mode);
+}
+
+/* Work out whether a path is valid (if not a display_log occurs), a directory
+ * (1 is returned) or a file *or* non-existent (0 is returned).
+ *
+ * Used for a write path.
+ */
+static int
+isdir(struct display *dp, const char *pathname)
+{
+   if (pathname == NULL)
+      return 0; /* stdout */
+
+   else if (pathname[0] == 0)
+      return 1; /* empty string */
+
+   else
+   {
+      struct stat buf;
+      int ret = stat(pathname, &buf);
+
+      if (ret == 0) /* the entry exists */
+      {
+         if (S_ISDIR(buf.st_mode))
+            return 1;
+
+         /* Else expect an object that exists and can be written: */
+         if (access(pathname, W_OK) != 0)
+            display_log(dp, USER_ERROR, "%s: cannot be written (%s)", pathname,
+                  strerror(errno));
+
+         return 0; /* file (exists, can be written) */
+      }
+
+      else /* an error */
+      {
+         /* Non-existence is fine, other errors are not: */
+         if (errno != ENOENT)
+            display_log(dp, USER_ERROR, "%s: invalid output name (%s)",
+                  pathname, strerror(errno));
+
+         return 0; /* file (does not exist) */
+      }
+   }
+}
+
+static void
+makename(struct display *dp, const char *dir, const char *infile)
+{
+   /* Make a name for an output file (and check it). */
+   dp->namebuf[0] = 0;
+
+   if (dir == NULL || infile == NULL)
+      display_log(dp, INTERNAL_ERROR, "NULL name to makename");
+
+   else
+   {
+      size_t dsize = strlen(dir);
+
+      if (dsize <= (sizeof dp->namebuf)-2) /* Allow for name + '/' + '\0' */
+      {
+         size_t isize = strlen(infile);
+         size_t istart = isize-1;
+
+         /* This should fail before here: */
+         if (infile[istart] == '/')
+            display_log(dp, INTERNAL_ERROR, "infile with trailing /");
+
+         memcpy(dp->namebuf, dir, dsize);
+         if (dsize > 0 && dp->namebuf[dsize-1] != '/')
+            dp->namebuf[dsize++] = '/';
+
+         /* Find the rightmost non-/ character: */
+         while (istart > 0 && infile[istart-1] != '/')
+            --istart;
+
+         isize -= istart;
+         infile += istart;
+
+         if (dsize+isize < (sizeof dp->namebuf)) /* dsize + infile + '\0' */
+         {
+            memcpy(dp->namebuf+dsize, infile, isize+1);
+
+            if (isdir(dp, dp->namebuf))
+               display_log(dp, USER_ERROR, "%s: output file is a directory",
+                     dp->namebuf);
+         }
+
+         else
+         {
+            dp->namebuf[dsize] = 0; /* allowed for: -2 at start */
+            display_log(dp, USER_ERROR, "%s%s: output file name too long",
+                  dp->namebuf, infile);
+         }
+      }
+
+      else
+         display_log(dp, USER_ERROR, "%s: output directory name too long", dir);
+   }
+}
+
+/* error handler callbacks for libpng */
+static void PNGCBAPI
+display_warning(png_structp pp, png_const_charp warning)
+{
+   struct display *dp = get_dp(pp);
+
+   /* This is used to prevent repeated warnings while searching */
+   if (!dp->no_warnings)
+      display_log(get_dp(pp), LIBPNG_WARNING, "%s", warning);
+}
+
+static void PNGCBAPI
+display_error(png_structp pp, png_const_charp error)
+{
+   struct display *dp = get_dp(pp);
+
+   display_log(dp, LIBPNG_ERROR, "%s", error);
+}
+
+static void
+display_start_read(struct display *dp, const char *filename)
+{
+   if (filename != NULL)
+   {
+      dp->filename = filename;
+      dp->fp = fopen(filename, "rb");
+   }
+
+   else
+   {
+      dp->filename = "<stdin>";
+      dp->fp = stdin;
+   }
+
+   dp->w = dp->h = 0U;
+   dp->bpp = 0U;
+   dp->size = 0U;
+   dp->read_size = 0U;
+
+   if (dp->fp == NULL)
+      display_log(dp, USER_ERROR, "file open failed (%s)", strerror(errno));
+}
+
+static void PNGCBAPI
+read_function(png_structp pp, png_bytep data, size_t size)
+{
+   struct display *dp = get_dp(pp);
+
+   if (size == 0U || fread(data, size, 1U, dp->fp) == 1U)
+      dp->read_size += size;
+
+   else
+   {
+      if (feof(dp->fp))
+         display_log(dp, LIBPNG_ERROR, "PNG file truncated");
+      else
+         display_log(dp, LIBPNG_ERROR, "PNG file read failed (%s)",
+               strerror(errno));
+   }
+}
+
+static void
+read_png(struct display *dp, const char *filename)
+{
+   display_clean_read(dp); /* safety */
+   display_start_read(dp, filename);
+
+   dp->read_pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, dp,
+      display_error, display_warning);
+   if (dp->read_pp == NULL)
+      display_log(dp, LIBPNG_ERROR, "failed to create read struct");
+
+#  ifdef PNG_BENIGN_ERRORS_SUPPORTED
+      png_set_benign_errors(dp->read_pp, 1/*allowed*/);
+#  endif /* BENIGN_ERRORS */
+
+#  ifdef FIX_INDEX
+      if ((dp->options & FIX_INDEX) != 0)
+         png_set_check_for_invalid_index(dp->read_pp, 1/*on, no warning*/);
+#     ifdef IGNORE_INDEX
+         else
+#     endif /* IGNORE_INDEX */
+#  endif /* FIX_INDEX */
+#  ifdef IGNORE_INDEX
+      if ((dp->options & IGNORE_INDEX) != 0) /* DANGEROUS */
+         png_set_check_for_invalid_index(dp->read_pp, -1/*off completely*/);
+#  endif /* IGNORE_INDEX */
+
+   /* The png_read_png API requires us to make the info struct, but it does the
+    * call to png_read_info.
+    */
+   dp->ip = png_create_info_struct(dp->read_pp);
+   if (dp->ip == NULL)
+      png_error(dp->read_pp, "failed to create info struct");
+
+   /* Set the IO handling */
+   png_set_read_fn(dp->read_pp, dp, read_function);
+
+#  ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      png_set_keep_unknown_chunks(dp->read_pp, PNG_HANDLE_CHUNK_ALWAYS, NULL,
+            0);
+#  endif /* HANDLE_AS_UNKNOWN */
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      /* Remove the user limits, if any */
+      png_set_user_limits(dp->read_pp, 0x7fffffff, 0x7fffffff);
+#  endif /* SET_USER_LIMITS */
+
+   /* Now read the PNG. */
+   start_timer(dp, PNGCP_TIME_READ);
+   png_read_png(dp->read_pp, dp->ip, 0U/*transforms*/, NULL/*params*/);
+   end_timer(dp, PNGCP_TIME_READ);
+   dp->w = png_get_image_width(dp->read_pp, dp->ip);
+   dp->h = png_get_image_height(dp->read_pp, dp->ip);
+   dp->ct = png_get_color_type(dp->read_pp, dp->ip);
+   dp->bpp = png_get_bit_depth(dp->read_pp, dp->ip) *
+             png_get_channels(dp->read_pp, dp->ip);
+   {
+      /* png_get_rowbytes should never return 0 because the value is set by the
+       * first call to png_set_IHDR, which should have happened by now, but just
+       * in case:
+       */
+      png_alloc_size_t rb = png_get_rowbytes(dp->read_pp, dp->ip);
+
+      if (rb == 0)
+         png_error(dp->read_pp, "invalid row byte count from libpng");
+
+      /* The size calc can overflow. */
+      if ((MAX_SIZE-dp->h)/rb < dp->h)
+         png_error(dp->read_pp, "image too large");
+
+      dp->size = rb * dp->h + dp->h/*filter byte*/;
+   }
+
+#ifdef FIX_INDEX
+   if (dp->ct == PNG_COLOR_TYPE_PALETTE && (dp->options & FIX_INDEX) != 0)
+   {
+      int max = png_get_palette_max(dp->read_pp, dp->ip);
+      png_colorp palette = NULL;
+      int num = -1;
+
+      if (png_get_PLTE(dp->read_pp, dp->ip, &palette, &num) != PNG_INFO_PLTE
+          || max < 0 || num <= 0 || palette == NULL)
+         display_log(dp, LIBPNG_ERROR, "invalid png_get_PLTE result");
+
+      if (max >= num)
+      {
+         /* 'Fix' the palette. */
+         int i;
+         png_color newpal[256];
+
+         for (i=0; i<num; ++i)
+            newpal[i] = palette[i];
+
+         /* Fill in any remainder with a warning color: */
+         for (; i<=max; ++i)
+         {
+            newpal[i].red = 0xbe;
+            newpal[i].green = 0xad;
+            newpal[i].blue = 0xed;
+         }
+
+         png_set_PLTE(dp->read_pp, dp->ip, newpal, i);
+      }
+   }
+#endif /* FIX_INDEX */
+
+   display_clean_read(dp);
+   dp->operation = "none";
+}
+
+static void
+display_start_write(struct display *dp, const char *filename)
+{
+   assert(dp->fp == NULL);
+
+   if ((dp->options & NOWRITE) != 0)
+      dp->output_file = "<no write>";
+
+   else
+   {
+      if (filename != NULL)
+      {
+         dp->output_file = filename;
+         dp->fp = fopen(filename, "wb");
+      }
+
+      else
+      {
+         dp->output_file = "<stdout>";
+         dp->fp = stdout;
+      }
+
+      if (dp->fp == NULL)
+         display_log(dp, USER_ERROR, "%s: file open failed (%s)",
+               dp->output_file, strerror(errno));
+   }
+}
+
+static void PNGCBAPI
+write_function(png_structp pp, png_bytep data, size_t size)
+{
+   struct display *dp = get_dp(pp);
+
+   /* The write fail is classed as a USER_ERROR, so --quiet does not turn it
+    * off, this seems more likely to be correct.
+    */
+   if (dp->fp == NULL || fwrite(data, size, 1U, dp->fp) == 1U)
+   {
+      dp->write_size += size;
+      if (dp->write_size < size || dp->write_size == MAX_SIZE)
+         png_error(pp, "IDAT size overflow");
+   }
+
+   else
+      display_log(dp, USER_ERROR, "%s: PNG file write failed (%s)",
+            dp->output_file, strerror(errno));
+}
+
+/* Compression option, 'method' is never set: there is no choice.
+ *
+ * IMPORTANT: the order of the entries in this macro determines the preference
+ * order when two different combos of two of these options produce an IDAT of
+ * the same size.  The logic here is to put the things that affect the decoding
+ * of the PNG image ahead of those that are relevant only to the encoding.
+ */
+#define SET_COMPRESSION\
+   SET(strategy, strategy);\
+   SET(windowBits, window_bits);\
+   SET(level, level);\
+   SET(memLevel, mem_level);
+
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+static void
+search_compression(struct display *dp)
+{
+   /* Like set_compression below but use a more restricted search than 'all' */
+   int val;
+
+#  define SET(name, func) if (getsearchopts(dp, #name, &val))\
+      png_set_compression_ ## func(dp->write_pp, val);
+   SET_COMPRESSION
+#  undef SET
+}
+
+static void
+set_compression(struct display *dp)
+{
+   int val;
+
+#  define SET(name, func) if (getallopts(dp, #name, &val))\
+      png_set_compression_ ## func(dp->write_pp, val);
+   SET_COMPRESSION
+#  undef SET
+}
+
+#ifdef PNG_SW_COMPRESS_level /* 1.7.0+ */
+static void
+set_ICC_profile_compression(struct display *dp)
+{
+   int val;
+
+#  define SET(name, func) if (getallopts(dp, "ICC-profile-" #name, &val))\
+      png_set_ICC_profile_compression_ ## func(dp->write_pp, val);
+   SET_COMPRESSION
+#  undef SET
+}
+#else
+#  define set_ICC_profile_compression(dp) ((void)0)
+#endif
+#else
+#  define search_compression(dp) ((void)0)
+#  define set_compression(dp) ((void)0)
+#  define set_ICC_profile_compression(dp) ((void)0)
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+static void
+set_text_compression(struct display *dp)
+{
+   int val;
+
+#  define SET(name, func) if (getallopts(dp, "text-" #name, &val))\
+      png_set_text_compression_ ## func(dp->write_pp, val);
+   SET_COMPRESSION
+#  undef SET
+}
+#else
+#  define set_text_compression(dp) ((void)0)
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+
+static void
+write_png(struct display *dp, const char *destname)
+{
+   display_clean_write(dp); /* safety */
+   display_start_write(dp, destname);
+
+   dp->write_pp = png_create_write_struct(PNG_LIBPNG_VER_STRING, dp,
+      display_error, display_warning);
+
+   if (dp->write_pp == NULL)
+      display_log(dp, LIBPNG_ERROR, "failed to create write png_struct");
+
+#  ifdef PNG_BENIGN_ERRORS_SUPPORTED
+      png_set_benign_errors(dp->write_pp, 1/*allowed*/);
+#  endif /* BENIGN_ERRORS */
+
+   png_set_write_fn(dp->write_pp, dp, write_function, NULL/*flush*/);
+
+#ifdef IGNORE_INDEX
+   if ((dp->options & IGNORE_INDEX) != 0) /* DANGEROUS */
+      png_set_check_for_invalid_index(dp->write_pp, -1/*off completely*/);
+#endif /* IGNORE_INDEX */
+
+   /* Restore the text chunks when using libpng 1.6 or less; this is a macro
+    * which expands to nothing in 1.7+  In earlier versions it tests
+    * dp->text_stashed, which is only set (below) *after* the first write.
+    */
+   text_restore(dp);
+
+#  ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      png_set_keep_unknown_chunks(dp->write_pp, PNG_HANDLE_CHUNK_ALWAYS, NULL,
+            0);
+#  endif /* HANDLE_AS_UNKNOWN */
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      /* Remove the user limits, if any */
+      png_set_user_limits(dp->write_pp, 0x7fffffff, 0x7fffffff);
+#  endif
+
+   /* OPTION HANDLING */
+   /* compression outputs, IDAT and zTXt/iTXt: */
+   dp->tsp = dp->nsp;
+   dp->nsp = dp->csp = 0;
+#  ifdef PNG_SW_COMPRESS_png_level
+      {
+         int val;
+
+         /* This sets everything, but then the following options just override
+          * the specific settings for ICC profiles and text.
+          */
+         if (getallopts(dp, "compression", &val))
+            png_set_compression(dp->write_pp, val);
+
+         if (getallopts(dp, "ICC-profile-compression", &val))
+            png_set_ICC_profile_compression(dp->write_pp, val);
+
+         if (getallopts(dp, "text-compression", &val))
+            png_set_text_compression(dp->write_pp, val);
+      }
+#  endif /* png_level support */
+   if (dp->options & SEARCH)
+      search_compression(dp);
+   else
+      set_compression(dp);
+   set_ICC_profile_compression(dp);
+   set_text_compression(dp);
+
+   {
+      int val;
+
+      /* The permitted range is 1..0x7FFFFFFF, so the cast is safe */
+      if (get_option(dp, "IDAT-size", &val))
+         png_set_IDAT_size(dp->write_pp, val);
+   }
+
+   /* filter handling */
+#  ifdef PNG_WRITE_FILTER_SUPPORTED
+      {
+         int val;
+
+         if (get_option(dp, "filter", &val))
+            png_set_filter(dp->write_pp, PNG_FILTER_TYPE_BASE, val);
+      }
+#  endif /* WRITE_FILTER */
+
+   /* This just uses the 'read' info_struct directly, it contains the image. */
+   dp->write_size = 0U;
+   start_timer(dp, PNGCP_TIME_WRITE);
+   png_write_png(dp->write_pp, dp->ip, 0U/*transforms*/, NULL/*params*/);
+   end_timer(dp, PNGCP_TIME_WRITE);
+
+   /* Make sure the file was written ok: */
+   if (dp->fp != NULL)
+   {
+      FILE *fp = dp->fp;
+      dp->fp = NULL;
+      if (fclose(fp))
+         display_log(dp, APP_ERROR, "%s: write failed (%s)",
+               destname == NULL ? "stdout" : destname, strerror(errno));
+   }
+
+   /* Clean it on the way out - if control returns to the caller then the
+    * written_file contains the required data.
+    */
+   display_clean_write(dp);
+   dp->operation = "none";
+}
+
+static void
+set_windowBits_hi(struct display *dp)
+{
+   /* windowBits is in the range 8..15 but zlib maps '8' to '9' so it is only
+    * worth using if the data size is 256 byte or less.
+    */
+   int wb = MAX_WBITS; /* for large images */
+   int i = VLSIZE(windowBits_IDAT);
+
+   while (wb > 8 && dp->size <= 1U<<(wb-1)) --wb;
+
+   while (--i >= 0) if (VLNAME(windowBits_IDAT)[i].name == range_hi) break;
+
+   assert(i > 1); /* vl_windowBits_IDAT always has a RANGE() */
+   VLNAME(windowBits_IDAT)[i].value = wb;
+
+   assert(VLNAME(windowBits_IDAT)[--i].name == range_lo);
+   VLNAME(windowBits_IDAT)[i].value = wb > 8 ? 9 : 8;
+
+   /* If wb == 8 then any search has been restricted to just one windowBits
+    * entry.  Record that here to avoid producing a spurious app-level warning
+    * above.
+    */
+   if (wb == 8)
+      dp->min_windowBits = OPTIND(dp, windowBits);
+}
+
+static int
+better_options(const struct display *dp)
+{
+   /* Are these options better than the best found so far?  Normally the
+    * options are tested in preference order, best first, however when doing a
+    * search operation on a range the range values are tested out of order.  In
+    * that case preferable options will get tested later.
+    *
+    * This function looks through the stack from the bottom up looking for an
+    * option that does not match the current best value.  When it finds one it
+    * checks to see if it is more or less desirable and returns true or false
+    * as appropriate.
+    *
+    * Notice that this means that the order options are pushed onto the stack
+    * conveys a priority; lower/earlier options are more important than later
+    * ones.
+    */
+   unsigned int sp;
+
+   for (sp=0; sp<dp->csp; ++sp)
+   {
+      int c = compare_option(dp, sp);
+
+      if (c < 0)
+         return 0; /* worse */
+
+      else if (c > 0)
+         return 1; /* better */
+   }
+
+   assert(0 && "unreached");
+}
+
+static void
+print_search_results(struct display *dp)
+{
+   assert(dp->filename != NULL);
+   printf("%s [%ld x %ld %d bpp %s, %lu bytes] %lu -> %lu with '%s'\n",
+      dp->filename, (unsigned long)dp->w, (unsigned long)dp->h, dp->bpp,
+      cts(dp->ct), (unsigned long)dp->size, (unsigned long)dp->read_size,
+      (unsigned long)dp->best_size, dp->best);
+   fflush(stdout);
+}
+
+static void
+log_search(struct display *dp, unsigned int log_depth)
+{
+   /* Log, and reset, the search so far: */
+   if (dp->nsp/*next entry to change*/ <= log_depth)
+   {
+      print_search_results(dp);
+      /* Start again with this entry: */
+      dp->best_size = MAX_SIZE;
+   }
+}
+
+static void
+cp_one_file(struct display *dp, const char *filename, const char *destname)
+{
+   unsigned int log_depth;
+
+   dp->filename = filename;
+   dp->operation = "read";
+   dp->no_warnings = 0;
+
+   /* Read it then write it: */
+   if (filename != NULL && access(filename, R_OK) != 0)
+      display_log(dp, USER_ERROR, "%s: invalid file name (%s)",
+            filename, strerror(errno));
+
+   read_png(dp, filename);
+
+   /* But 'destname' may be a directory. */
+   dp->operation = "write";
+
+   /* Limit the upper end of the windowBits range for this file */
+   set_windowBits_hi(dp);
+
+   /* For logging, depth to log: */
+   {
+      int val;
+
+      if (get_option(dp, "log-depth", &val) && val >= 0)
+         log_depth = (unsigned int)/*SAFE*/val;
+
+      else
+         log_depth = 0U;
+   }
+
+   if (destname != NULL) /* else stdout */
+   {
+      if (isdir(dp, destname))
+      {
+         makename(dp, destname, filename);
+         destname = dp->namebuf;
+      }
+
+      else if (access(destname, W_OK) != 0 && errno != ENOENT)
+         display_log(dp, USER_ERROR, "%s: invalid output name (%s)", destname,
+               strerror(errno));
+   }
+
+   dp->nsp = 0;
+   dp->curr[0] = 0; /* acts as a flag for the caller */
+   dp->opt_string_start = 0;
+   dp->best[0] = 0; /* safety */
+   dp->best_size = MAX_SIZE;
+   write_png(dp, destname);
+
+   /* Initialize the 'best' fields: */
+   strcpy(dp->best, dp->curr);
+   dp->best_size = dp->write_size;
+
+   if (dp->nsp > 0) /* iterating over lists */
+   {
+      char *tmpname, tmpbuf[(sizeof dp->namebuf) + 4];
+      assert(dp->curr[0] == ' ' && dp->tsp > 0);
+
+      /* Cancel warnings on subsequent writes */
+      log_search(dp, log_depth);
+      dp->no_warnings = 1;
+
+      /* Make a temporary name for the subsequent tests: */
+      if (destname != NULL)
+      {
+         strcpy(tmpbuf, destname);
+         strcat(tmpbuf, ".tmp"); /* space for .tmp allocated above */
+         tmpname = tmpbuf;
+      }
+
+      else
+         tmpname = NULL; /* stdout */
+
+      /* Loop to find the best option. */
+      do
+      {
+         write_png(dp, tmpname);
+
+         /* And compare the sizes (the write function makes sure write_size
+          * doesn't overflow.)
+          */
+         assert(dp->csp > 0);
+
+         if (dp->write_size < dp->best_size ||
+             (dp->write_size == dp->best_size && better_options(dp)))
+         {
+            if (destname != NULL && rename(tmpname, destname) != 0)
+               display_log(dp, APP_ERROR, "rename %s %s failed (%s)", tmpname,
+                     destname, strerror(errno));
+
+            strcpy(dp->best, dp->curr);
+            dp->best_size = dp->write_size;
+         }
+
+         else if (tmpname != NULL && unlink(tmpname) != 0)
+            display_log(dp, APP_WARNING, "unlink %s failed (%s)", tmpname,
+                  strerror(errno));
+
+         log_search(dp, log_depth);
+      }
+      while (dp->nsp > 0);
+
+      /* Do this for the 'sizes' option so that it reports the correct size. */
+      dp->write_size = dp->best_size;
+   }
+}
+
+static int
+cppng(struct display *dp, const char *file, const char *gv dest)
+   /* Exists solely to isolate the setjmp clobbers which some versions of GCC
+    * erroneously generate.
+    */
+{
+   int ret = setjmp(dp->error_return);
+
+   if (ret == 0)
+   {
+      dp->errset = 1;
+      cp_one_file(dp, file, dest);
+      dp->errset = 0;
+      return 0;
+   }
+
+   else
+   {
+      dp->errset = 0;
+
+      if (ret < ERRORS) /* shouldn't longjmp on warnings */
+         display_log(dp, INTERNAL_ERROR, "unexpected return code %d", ret);
+
+      return ret;
+   }
+}
+
+int
+main(int argc, char **argv)
+{
+   /* For each file on the command line test it with a range of transforms */
+   int option_end;
+   struct display d;
+
+   display_init(&d);
+
+   d.operation = "options";
+   for (option_end = 1;
+        option_end < argc && opt_check(&d, argv[option_end]);
+        ++option_end)
+   {
+   }
+
+   /* Do a quick check on the directory target case; when there are more than
+    * two arguments the last one must be a directory.
+    */
+   if (!(d.options & NOWRITE) && option_end+2 < argc && !checkdir(argv[argc-1]))
+   {
+      fprintf(stderr,
+            "pngcp: %s: directory required with more than two arguments\n",
+            argv[argc-1]);
+      return 99;
+   }
+
+   {
+      int errors = 0;
+      int i = option_end;
+
+      /* Do this at least once; if there are no arguments stdin/stdout are used.
+       */
+      d.operation = "files";
+      do
+      {
+         const char *infile = NULL;
+         const char *outfile = NULL;
+         int ret;
+
+         if (i < argc)
+         {
+            infile = argv[i++];
+            if (!(d.options & NOWRITE) && i < argc)
+               outfile = argv[argc-1];
+         }
+
+         ret = cppng(&d, infile, outfile);
+
+         if (ret)
+         {
+            if (ret > QUIET) /* abort on user or internal error */
+               return 99;
+
+            /* An error: the output is meaningless */
+         }
+
+         else if (d.best[0] != 0)
+         {
+            /* This result may already have been output, in which case best_size
+             * has been reset.
+             */
+            if (d.best_size < MAX_SIZE)
+               print_search_results(&d);
+         }
+
+         else if (d.options & SIZES)
+         {
+            printf("%s [%ld x %ld %d bpp %s, %lu bytes] %lu -> %lu [0x%lx]\n",
+                  infile, (unsigned long)d.w, (unsigned long)d.h, d.bpp,
+                  cts(d.ct), (unsigned long)d.size, (unsigned long)d.read_size,
+                  (unsigned long)d.write_size, (unsigned long)d.results);
+            fflush(stdout);
+         }
+
+         /* Here on any return, including failures, except user/internal issues
+          */
+         {
+            int pass = (d.options & STRICT) ?
+               RESULT_STRICT(d.results) : RESULT_RELAXED(d.results);
+
+            if (!pass)
+               ++errors;
+
+            if (d.options & LOG)
+            {
+               int j;
+
+               printf("%s: pngcp", pass ? "PASS" : "FAIL");
+
+               for (j=1; j<option_end; ++j)
+                  printf(" %s", argv[j]);
+
+               if (infile != NULL)
+                  printf(" %s", infile);
+
+#              ifdef PNG_PNGCP_TIMING_SUPPORTED
+                  /* When logging output the files for each file, if enabled. */
+                  if ((d.value[OPTIND(&d,time)] & PNGCP_TIME_READ) != 0)
+                     print_time(" read", d.read_time);
+
+                  if ((d.value[OPTIND(&d,time)] & PNGCP_TIME_WRITE) != 0)
+                     print_time(" write", d.write_time);
+#              endif /* PNGCP_TIMING */
+
+               printf("\n");
+               fflush(stdout);
+            }
+         }
+
+         display_clean(&d);
+      }
+      while (i+!(d.options & NOWRITE) < argc);
+         /* I.e. for write cases after the first time through the loop require
+          * there to be at least two arguments left and for the last one to be a
+          * directory (this was checked above).
+          */
+
+      /* Release allocated memory */
+      display_destroy(&d);
+
+#     ifdef PNG_PNGCP_TIMING_SUPPORTED
+         {
+            int output = 0;
+
+            if ((d.value[OPTIND(&d,time)] & PNGCP_TIME_READ) != 0)
+               print_time("read", d.read_time_total), output = 1;
+
+            if ((d.value[OPTIND(&d,time)] & PNGCP_TIME_WRITE) != 0)
+            {
+               if (output) putchar(' ');
+               print_time("write", d.write_time_total);
+               output = 1;
+            }
+
+            if (output) putchar('\n');
+         }
+#     endif /* PNGCP_TIMING */
+
+      return errors != 0;
+   }
+}
+#else /* !READ_PNG || !WRITE_PNG */
+int
+main(void)
+{
+   fprintf(stderr, "pngcp: no support for png_read/write_image\n");
+   return 77;
+}
+#endif /* !READ_PNG || !WRITE_PNG */
diff --git a/extern/libpng/contrib/tools/pngfix.c b/extern/libpng/contrib/tools/pngfix.c
new file mode 100644
index 0000000000..2fa5d13eaf
--- /dev/null
+++ b/extern/libpng/contrib/tools/pngfix.c
@@ -0,0 +1,4049 @@
+/* pngfix.c
+ *
+ * Last changed in libpng 1.6.31 [July 27, 2017]
+ * Copyright (c) 2014-2017 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Tool to check and fix the zlib inflate 'too far back' problem.
+ * See the usage message for more information.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.h>
+#include <errno.h>
+#include <assert.h>
+
+#define implies(x,y) assert(!(x) || (y))
+
+#ifdef __GNUC__
+   /* This is used to fix the error:
+    *
+    * pngfix.c:
+    * In function 'zlib_advance':
+    * pngfix.c:181:13: error: assuming signed overflow does not
+    *   occur when simplifying conditional to constant [-Werror=strict-overflow]
+    */
+#  define FIX_GCC volatile
+#else
+#  define FIX_GCC
+#endif
+
+#define PROGRAM_NAME "pngfix"
+
+/* Define the following to use this program against your installed libpng,
+ * rather than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#if PNG_LIBPNG_VER < 10603 /* 1.6.3 */
+#  error "pngfix will not work with libpng prior to 1.6.3"
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+#include <setjmp.h>
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_EASY_ACCESS_SUPPORTED) &&\
+   (defined(PNG_READ_DEINTERLACE_SUPPORTED) ||\
+    defined(PNG_READ_INTERLACING_SUPPORTED))
+
+/* zlib.h defines the structure z_stream, an instance of which is included
+ * in this structure and is required for decompressing the LZ compressed
+ * data in PNG files.
+ */
+#ifndef ZLIB_CONST
+   /* We must ensure that zlib uses 'const' in declarations. */
+#  define ZLIB_CONST
+#endif
+#include <zlib.h>
+#ifdef const
+   /* zlib.h sometimes #defines const to nothing, undo this. */
+#  undef const
+#endif
+
+/* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
+ * with older builds.
+ */
+#if ZLIB_VERNUM < 0x1260
+#  define PNGZ_MSG_CAST(s) constcast(char*,s)
+#  define PNGZ_INPUT_CAST(b) constcast(png_bytep,b)
+#else
+#  define PNGZ_MSG_CAST(s) (s)
+#  define PNGZ_INPUT_CAST(b) (b)
+#endif
+
+#ifndef PNG_MAXIMUM_INFLATE_WINDOW
+#  error "pngfix not supported in this libpng version"
+#endif
+
+#if ZLIB_VERNUM >= 0x1240
+
+/* Copied from pngpriv.h */
+#ifdef __cplusplus
+#  define voidcast(type, value) static_cast<type>(value)
+#  define constcast(type, value) const_cast<type>(value)
+#  define aligncast(type, value) \
+   static_cast<type>(static_cast<void*>(value))
+#  define aligncastconst(type, value) \
+   static_cast<type>(static_cast<const void*>(value))
+#else
+#  define voidcast(type, value) (value)
+#  define constcast(type, value) ((type)(value))
+#  define aligncast(type, value) ((void*)(value))
+#  define aligncastconst(type, value) ((const void*)(value))
+#endif /* __cplusplus */
+
+#if PNG_LIBPNG_VER < 10700
+/* Chunk tags (copied from pngpriv.h) */
+#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
+#define PNG_U32(b1,b2,b3,b4) \
+   (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
+
+/* Constants for known chunk types. */
+#define png_IDAT PNG_U32( 73,  68,  65,  84)
+#define png_IEND PNG_U32( 73,  69,  78,  68)
+#define png_IHDR PNG_U32( 73,  72,  68,  82)
+#define png_PLTE PNG_U32( 80,  76,  84,  69)
+#define png_bKGD PNG_U32( 98,  75,  71,  68)
+#define png_cHRM PNG_U32( 99,  72,  82,  77)
+#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
+#define png_gAMA PNG_U32(103,  65,  77,  65)
+#define png_gIFg PNG_U32(103,  73,  70, 103)
+#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
+#define png_gIFx PNG_U32(103,  73,  70, 120)
+#define png_hIST PNG_U32(104,  73,  83,  84)
+#define png_iCCP PNG_U32(105,  67,  67,  80)
+#define png_iTXt PNG_U32(105,  84,  88, 116)
+#define png_oFFs PNG_U32(111,  70,  70, 115)
+#define png_pCAL PNG_U32(112,  67,  65,  76)
+#define png_pHYs PNG_U32(112,  72,  89, 115)
+#define png_sBIT PNG_U32(115,  66,  73,  84)
+#define png_sCAL PNG_U32(115,  67,  65,  76)
+#define png_sPLT PNG_U32(115,  80,  76,  84)
+#define png_sRGB PNG_U32(115,  82,  71,  66)
+#define png_sTER PNG_U32(115,  84,  69,  82)
+#define png_tEXt PNG_U32(116,  69,  88, 116)
+#define png_tIME PNG_U32(116,  73,  77,  69)
+#define png_tRNS PNG_U32(116,  82,  78,  83)
+#define png_zTXt PNG_U32(122,  84,  88, 116)
+#endif
+
+/* The 8-byte signature as a pair of 32-bit quantities */
+#define sig1 PNG_U32(137,  80,  78,  71)
+#define sig2 PNG_U32( 13,  10,  26,  10)
+
+/* Is the chunk critical? */
+#define CRITICAL(chunk) (((chunk) & PNG_U32(32,0,0,0)) == 0)
+
+/* Is it safe to copy? */
+#define SAFE_TO_COPY(chunk) (((chunk) & PNG_U32(0,0,0,32)) != 0)
+
+/* Fix ups for builds with limited read support */
+#ifndef PNG_ERROR_TEXT_SUPPORTED
+#  define png_error(a,b) png_err(a)
+#endif
+
+/********************************* UTILITIES **********************************/
+/* UNREACHED is a value to cause an assert to fail. Because of the way the
+ * assert macro is written the string "UNREACHED" is produced in the error
+ * message.
+ */
+#define UNREACHED 0
+
+/* 80-bit number handling - a PNG image can be up to (2^31-1)x(2^31-1) 8-byte
+ * (16-bit RGBA) pixels in size; that's less than 2^65 bytes or 2^68 bits, so
+ * arithmetic of 80-bit numbers is sufficient.  This representation uses an
+ * arbitrary length array of png_uint_16 digits (0..65535).  The representation
+ * is little endian.
+ *
+ * The arithmetic functions take zero to two uarb values together with the
+ * number of digits in those values and write the result to the given uarb
+ * (always the first argument) returning the number of digits in the result.
+ * If the result is negative the return value is also negative (this would
+ * normally be an error).
+ */
+typedef png_uint_16  udigit; /* A 'unum' is an array of these */
+typedef png_uint_16p uarb;
+typedef png_const_uint_16p uarbc;
+
+#define UDIGITS(unum) ((sizeof unum)/(sizeof (udigit))
+   /* IMPORTANT: only apply this to an array, applied to a pointer the result
+    * will typically be '2', which is not useful.
+    */
+
+static int
+uarb_set(uarb result, png_alloc_size_t val)
+   /* Set (initialize) 'result' to 'val'.  The size required for 'result' must
+    * be determined by the caller from a knowledge of the maximum for 'val'.
+    */
+{
+   int ndigits = 0;
+
+   while (val > 0)
+   {
+      result[ndigits++] = (png_uint_16)(val & 0xffff);
+      val >>= 16;
+   }
+
+   return ndigits;
+}
+
+static int
+uarb_copy(uarb to, uarb from, int idigits)
+   /* Copy a uarb, may reduce the digit count */
+{
+   int d, odigits;
+
+   for (d=odigits=0; d<idigits; ++d)
+      if ((to[d] = from[d]) != 0)
+         odigits = d+1;
+
+   return odigits;
+}
+
+static int
+uarb_inc(uarb num, int in_digits, png_int_32 add)
+   /* This is a signed 32-bit add, except that to avoid overflow the value added
+    * or subtracted must be no more than 2^31-65536.  A negative result
+    * indicates a negative number (which is an error below).  The size of
+    * 'num' should be max(in_digits+1,2) for arbitrary 'add' but can be just
+    * in_digits+1 if add is known to be in the range -65535..65535.
+    */
+{
+   FIX_GCC int out_digits = 0;
+
+   while (out_digits < in_digits)
+   {
+      add += num[out_digits];
+      num[out_digits++] = (png_uint_16)(add & 0xffff);
+      add >>= 16;
+   }
+
+   while (add != 0 && add != (-1))
+   {
+      num[out_digits++] = (png_uint_16)(add & 0xffff);
+      add >>= 16;
+   }
+
+   if (add == 0)
+   {
+      while (out_digits > 0 && num[out_digits-1] == 0)
+         --out_digits;
+      return out_digits; /* may be 0 */
+   }
+
+   else /* negative result */
+   {
+      while (out_digits > 1 && num[out_digits-1] == 0xffff)
+         --out_digits;
+
+      return -out_digits;
+   }
+}
+
+static int
+uarb_add32(uarb num, int in_digits, png_uint_32 add)
+   /* As above but this works with any 32-bit value and only does 'add' */
+{
+   if (in_digits > 0)
+   {
+      in_digits = uarb_inc(num, in_digits, add & 0xffff);
+      return uarb_inc(num+1, in_digits-1, add >> 16)+1;
+   }
+
+   return uarb_set(num, add);
+}
+
+static int
+uarb_mult_digit(uarb acc, int a_digits, uarb num, FIX_GCC int n_digits,
+   png_uint_16 val)
+   /* Primitive one-digit multiply - 'val' must be 0..65535. Note that this
+    * primitive is a multiply and accumulate - the result of *num * val is added
+    * to *acc.
+    *
+    * This is a one-digit multiply, so the product may be up to one digit longer
+    * than 'num', however the add to 'acc' means that the caller must ensure
+    * that 'acc' is at least one digit longer than this *and* at least one digit
+    * longer than the current length of 'acc'.  (Or the caller must otherwise
+    * ensure 'adigits' is adequate from knowledge of the values.)
+    */
+{
+   /* The digits in *acc, *num and val are in the range 0..65535, so the
+    * result below is at most (65535*65535)+2*65635 = 65535*(65535+2), which is
+    * exactly 0xffffffff.
+    */
+   if (val > 0 && n_digits > 0) /* Else the product is 0 */
+   {
+      png_uint_32 carry = 0;
+      int out_digits = 0;
+
+      while (out_digits < n_digits || carry > 0)
+      {
+         if (out_digits < a_digits)
+            carry += acc[out_digits];
+
+         if (out_digits < n_digits)
+            carry += (png_uint_32)num[out_digits] * val;
+
+         acc[out_digits++] = (png_uint_16)(carry & 0xffff);
+         carry >>= 16;
+      }
+
+      /* So carry is 0 and all the input digits have been consumed. This means
+       * that it is possible to skip any remaining digits in acc.
+       */
+      if (out_digits > a_digits)
+         return out_digits;
+   }
+
+   return a_digits;
+}
+
+static int
+uarb_mult32(uarb acc, int a_digits, uarb num, int n_digits, png_uint_32 val)
+   /* calculate acc += num * val, 'val' may be any 32-bit value, 'acc' and 'num'
+    * may be any value, returns the number of digits in 'acc'.
+    */
+{
+   if (n_digits > 0 && val > 0)
+   {
+      a_digits = uarb_mult_digit(acc, a_digits, num, n_digits,
+         (png_uint_16)(val & 0xffff));
+
+      val >>= 16;
+      if (val > 0)
+         a_digits = uarb_mult_digit(acc+1, a_digits-1, num, n_digits,
+            (png_uint_16)val) + 1;
+
+      /* Because n_digits and val are >0 the following must be true: */
+      assert(a_digits > 0);
+   }
+
+   return a_digits;
+}
+
+static int
+uarb_shift(uarb inout, int ndigits, unsigned int right_shift)
+   /* Shift inout right by right_shift bits, right_shift must be in the range
+    * 1..15
+    */
+{
+   FIX_GCC int i = ndigits;
+   png_uint_16 carry = 0;
+
+   assert(right_shift >= 1 && right_shift <= 15);
+
+   while (--i >= 0)
+   {
+      png_uint_16 temp = (png_uint_16)(carry | (inout[i] >> right_shift));
+
+      /* Bottom bits to top bits of carry */
+      carry = (png_uint_16)((inout[i] << (16-right_shift)) & 0xffff);
+
+      inout[i] = temp;
+
+      /* The shift may reduce ndigits */
+      if (i == ndigits-1 && temp == 0)
+         ndigits = i;
+   }
+
+   return ndigits;
+}
+
+static int
+uarb_cmp(uarb a, int adigits, uarb b, int bdigits)
+   /* Return -1/0/+1 according as a<b/a==b/a>b */
+{
+   if (adigits < bdigits)
+      return -1;
+
+   if (adigits > bdigits)
+      return 1;
+
+   while (adigits-- > 0)
+      if (a[adigits] < b[adigits])
+         return -1;
+
+      else if (a[adigits] > b[adigits])
+         return 1;
+
+   return 0;
+}
+
+#if 0 /*UNUSED*/
+static int
+uarb_eq32(uarb num, int digits, png_uint_32 val)
+   /* Return true if the uarb is equal to 'val' */
+{
+   switch (digits)
+   {
+      case 0:  return val == 0;
+      case 1:  return val == num[0];
+      case 2:  return (val & 0xffff) == num[0] && (val >> 16) == num[1];
+      default: return 0;
+   }
+}
+#endif
+
+static void
+uarb_printx(uarb num, int digits, FILE *out)
+   /* Print 'num' as a hexadecimal number (easier than decimal!) */
+{
+   while (digits > 0)
+      if (num[--digits] > 0)
+      {
+         fprintf(out, "0x%x", num[digits]);
+
+         while (digits > 0)
+            fprintf(out, "%.4x", num[--digits]);
+      }
+
+      else if (digits == 0) /* the number is 0 */
+         fputs("0x0", out);
+}
+
+static void
+uarb_print(uarb num, int digits, FILE *out)
+   /* Prints 'num' as a decimal if it will fit in an unsigned long, else as a
+    * hexadecimal number.  Notice that the results vary for images over 4GByte
+    * in a system dependent way, and the hexadecimal form doesn't work very well
+    * in awk script input.
+    *
+    *
+    * TODO: write uarb_div10
+    */
+{
+   if (digits * sizeof (udigit) > sizeof (unsigned long))
+      uarb_printx(num, digits, out);
+
+   else
+   {
+      unsigned long n = 0;
+
+      while (digits > 0)
+         n = (n << 16) + num[--digits];
+
+      fprintf(out, "%lu", n);
+   }
+}
+
+/* Generate random bytes.  This uses a boring repeatable algorithm and it
+ * is implemented here so that it gives the same set of numbers on every
+ * architecture.  It's a linear congruential generator (Knuth or Sedgewick
+ * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
+ * Hill, "The Art of Electronics" (Pseudo-Random Bit Sequences and Noise
+ * Generation.)
+ *
+ * (Copied from contrib/libtests/pngvalid.c)
+ */
+static void
+make_random_bytes(png_uint_32* seed, void* pv, size_t size)
+{
+   png_uint_32 u0 = seed[0], u1 = seed[1];
+   png_bytep bytes = voidcast(png_bytep, pv);
+
+   /* There are thirty-three bits; the next bit in the sequence is bit-33 XOR
+    * bit-20.  The top 1 bit is in u1, the bottom 32 are in u0.
+    */
+   size_t i;
+   for (i=0; i<size; ++i)
+   {
+      /* First generate 8 new bits then shift them in at the end. */
+      png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
+      u1 <<= 8;
+      u1 |= u0 >> 24;
+      u0 <<= 8;
+      u0 |= u;
+      *bytes++ = (png_byte)u;
+   }
+
+   seed[0] = u0;
+   seed[1] = u1;
+}
+
+/* Clear an object to a random value. */
+static void
+clear(void *pv, size_t size)
+{
+   static png_uint_32 clear_seed[2] = { 0x12345678, 0x9abcdef0 };
+   make_random_bytes(clear_seed, pv, size);
+}
+
+#define CLEAR(object) clear(&(object), sizeof (object))
+
+/* Copied from unreleased 1.7 code.
+ *
+ * CRC checking uses a local pre-built implementation of the Ethernet CRC32.
+ * This is to avoid a function call to the zlib DLL and to optimize the
+ * byte-by-byte case.
+ */
+static png_uint_32 crc_table[256] =
+{
+   0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
+   0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
+   0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
+   0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+   0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,
+   0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+   0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,
+   0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+   0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
+   0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,
+   0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
+   0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+   0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,
+   0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,
+   0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
+   0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+   0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,
+   0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+   0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,
+   0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+   0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
+   0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,
+   0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,
+   0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+   0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
+   0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,
+   0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
+   0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+   0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,
+   0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+   0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,
+   0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+   0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
+   0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,
+   0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,
+   0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+   0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,
+   0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,
+   0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
+   0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+   0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,
+   0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+   0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,
+   0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+   0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
+   0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
+   0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,
+   0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+   0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,
+   0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,
+   0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
+   0x2d02ef8d
+};
+
+/* The CRC calculated here *IS* conditioned, the corresponding value used by
+ * zlib and the result value is obtained by XORing with CRC_INIT, which is also
+ * the first value that must be passed in (for the first byte) to crc_one_byte.
+ */
+#define CRC_INIT 0xffffffff
+
+static png_uint_32
+crc_one_byte(png_uint_32 crc, int b)
+{
+   return crc_table[(crc ^ b) & 0xff] ^ (crc >> 8);
+}
+
+static png_uint_32
+crc_init_4(png_uint_32 value)
+{
+   /* This is an alternative to the algorithm used in zlib, which requires four
+    * separate tables to parallelize the four byte operations, it only works for
+    * a CRC of the first four bytes of the stream, but this is what happens in
+    * the parser below where length+chunk-name is read and chunk-name used to
+    * initialize the CRC.  Notice that the calculation here avoids repeated
+    * conditioning (xor with 0xffffffff) by storing the conditioned value.
+    */
+   png_uint_32 crc = crc_table[(~value >> 24)] ^ 0xffffff;
+
+   crc = crc_table[(crc ^ (value >> 16)) & 0xff] ^ (crc >> 8);
+   crc = crc_table[(crc ^ (value >> 8)) & 0xff] ^ (crc >> 8);
+   return crc_table[(crc ^ value) & 0xff] ^ (crc >> 8);
+}
+
+static int
+chunk_type_valid(png_uint_32 c)
+   /* Bit whacking approach to chunk name validation that is intended to avoid
+    * branches.  The cost is that it uses a lot of 32-bit constants, which might
+    * be bad on some architectures.
+    */
+{
+   png_uint_32 t;
+
+   /* Remove bit 5 from all but the reserved byte; this means every
+    * 8-bit unit must be in the range 65-90 to be valid.  So bit 5
+    * must be zero, bit 6 must be set and bit 7 zero.
+    */
+   c &= ~PNG_U32(32,32,0,32);
+   t = (c & ~0x1f1f1f1f) ^ 0x40404040;
+
+   /* Subtract 65 for each 8-bit quantity, this must not overflow
+    * and each byte must then be in the range 0-25.
+    */
+   c -= PNG_U32(65,65,65,65);
+   t |=c ;
+
+   /* Subtract 26, handling the overflow which should set the top
+    * three bits of each byte.
+    */
+   c -= PNG_U32(25,25,25,26);
+   t |= ~c;
+
+   return (t & 0xe0e0e0e0) == 0;
+}
+
+/**************************** CONTROL INFORMATION *****************************/
+
+/* Information about a sequence of IDAT chunks, the chunks have been re-synced
+ * using sync_stream below and the new lengths are recorded here.  Because the
+ * number of chunks is unlimited this is handled using a linked list of these
+ * structures.
+ */
+struct IDAT_list
+{
+   struct IDAT_list *next;     /* Linked list */
+   unsigned int      length;   /* Actual length of the array below */
+   unsigned int      count;    /* Number of entries that are valid */
+#     define IDAT_INIT_LENGTH 16
+   png_uint_32       lengths[IDAT_INIT_LENGTH];
+};
+
+static void
+IDAT_list_init(struct IDAT_list *list)
+{
+   CLEAR(*list);
+
+   list->next = NULL;
+   list->length = IDAT_INIT_LENGTH;
+}
+
+static size_t
+IDAT_list_size(struct IDAT_list *list, unsigned int length)
+   /* Return the size in bytes of an IDAT_list of the given length. */
+{
+   if (list != NULL)
+      length = list->length;
+
+   return sizeof *list - sizeof list->lengths +
+      length * sizeof list->lengths[0];
+}
+
+static void
+IDAT_list_end(struct IDAT_list *IDAT_list)
+{
+   struct IDAT_list *list = IDAT_list->next;
+
+   CLEAR(*IDAT_list);
+
+   while (list != NULL)
+   {
+      struct IDAT_list *next = list->next;
+
+      clear(list, IDAT_list_size(list, 0));
+      free(list);
+      list = next;
+   }
+}
+
+static struct IDAT_list *
+IDAT_list_extend(struct IDAT_list *tail)
+{
+   /* Use the previous cached value if available. */
+   struct IDAT_list *next = tail->next;
+
+   if (next == NULL)
+   {
+      /* Insert a new, malloc'ed, block of IDAT information buffers, this
+       * one twice as large as the previous one:
+       */
+      unsigned int length = 2 * tail->length;
+
+      if (length < tail->length) /* arithmetic overflow */
+         length = tail->length;
+
+      next = voidcast(IDAT_list*, malloc(IDAT_list_size(NULL, length)));
+      CLEAR(*next);
+
+      /* The caller must handle this: */
+      if (next == NULL)
+         return NULL;
+
+      next->next = NULL;
+      next->length = length;
+      tail->next = next;
+   }
+
+   return next;
+}
+
+/* GLOBAL CONTROL STRUCTURE */
+struct global
+{
+   /* PUBLIC GLOBAL VARIABLES: OWNER INITIALIZE */
+   unsigned int   errors        :1; /* print file errors to stderr */
+   unsigned int   warnings      :1; /* print libpng warnings to stderr */
+   unsigned int   optimize_zlib :1; /* Run optimization search */
+   unsigned int   quiet         :2; /* don't output summaries */
+   unsigned int   verbose       :3; /* various internal tracking */
+   unsigned int   skip          :3; /* Non-critical chunks to skip */
+#     define SKIP_NONE      0
+#     define SKIP_BAD_CRC   1    /* Chunks with a bad CRC */
+#     define SKIP_UNSAFE    2    /* Chunks not safe to copy */
+#     define SKIP_UNUSED    3    /* Chunks not used by libpng */
+#     define SKIP_TRANSFORM 4    /* Chunks only used in transforms */
+#     define SKIP_COLOR     5    /* Everything but tRNS, sBIT, gAMA and sRGB */
+#     define SKIP_ALL       6    /* Everything but tRNS and sBIT */
+
+   png_uint_32    idat_max;         /* 0 to perform no re-chunking */
+
+   int            status_code;      /* Accumulated status code */
+#     define TOO_FAR_BACK   0x01 /* found a too-far-back error */
+#     define CRC_ERROR      0x02 /* fixed an invalid CRC */
+#     define STREAM_ERROR   0x04 /* damaged PNG stream (may be fixable) */
+#     define TRUNCATED      0x08 /* truncated but still readable */
+#     define FILE_ERROR     0x10 /* could not read the file */
+#     define WRITE_ERROR    0x20 /* write error (this terminates the read) */
+#     define INTERNAL_ERROR 0x40 /* internal limits/errors encountered */
+
+   /* PUBLIC GLOBAL VARIABLES: USED INTERNALLY BY IDAT READ CODE */
+   struct IDAT_list idat_cache;  /* Cache of file IDAT information buffers */
+      /* The structure is shared across all uses of this global control
+       * structure to avoid reallocation between IDAT streams.
+       */
+};
+
+static int
+global_end(struct global *global)
+{
+
+   int rc;
+
+   IDAT_list_end(&global->idat_cache);
+   rc = global->status_code;
+   CLEAR(*global);
+   return rc;
+}
+
+static void
+global_init(struct global *global)
+   /* Call this once (and only once) to initialize the control */
+{
+   CLEAR(*global);
+
+   /* Globals */
+   global->errors        = 0;
+   global->warnings      = 0;
+   global->quiet         = 0;
+   global->verbose       = 0;
+   global->idat_max      = 0;         /* no re-chunking of IDAT */
+   global->optimize_zlib = 0;
+   global->skip          = SKIP_NONE;
+   global->status_code   = 0;
+
+   IDAT_list_init(&global->idat_cache);
+}
+
+static int
+skip_chunk_type(const struct global *global, png_uint_32 type)
+   /* Return true if this chunk is to be skipped according to the --strip
+    * option.  This code needs to recognize all known ancillary chunks in order
+    * to handle the --strip=unsafe option.
+    */
+{
+   /* Never strip critical chunks: */
+   if (CRITICAL(type))
+      return 0;
+
+   switch (type)
+   {
+      /* Chunks that are treated as, effectively, critical because they affect
+       * correct interpretation of the pixel values:
+       */
+      case png_tRNS: case png_sBIT:
+         return 0;
+
+      /* Chunks that specify gamma encoding which should therefore only be
+       * removed if the user insists:
+       */
+      case png_gAMA: case png_sRGB:
+         if (global->skip >= SKIP_ALL)
+            return 1;
+         return 0;
+
+      /* Chunks that affect color interpretation - not used by libpng and rarely
+       * used by applications, but technically still required for correct
+       * interpretation of the image data:
+       */
+      case png_cHRM: case png_iCCP:
+         if (global->skip >= SKIP_COLOR)
+            return 1;
+         return 0;
+
+      /* Other chunks that are used by libpng in image transformations (as
+       * opposed to known chunks that have get/set APIs but are not otherwise
+       * used.)
+       */
+      case png_bKGD:
+         if (global->skip >= SKIP_TRANSFORM)
+            return 1;
+         return 0;
+
+      /* All other chunks that libpng knows about and affect neither image
+       * interpretation nor libpng transforms - chunks that are effectively
+       * unused by libpng even though libpng might recognize and store them.
+       */
+      case png_fRAc: case png_gIFg: case png_gIFt: case png_gIFx: case png_hIST:
+      case png_iTXt: case png_oFFs: case png_pCAL: case png_pHYs: case png_sCAL:
+      case png_sPLT: case png_sTER: case png_tEXt: case png_tIME: case png_zTXt:
+         if (global->skip >= SKIP_UNUSED)
+            return 1;
+         return 0;
+
+      /* Chunks that libpng does not know about (notice that this depends on the
+       * list above including all known chunks!)  The decision here depends on
+       * whether the safe-to-copy bit is set in the chunk type.
+       */
+      default:
+         if (SAFE_TO_COPY(type))
+         {
+            if (global->skip >= SKIP_UNUSED) /* as above */
+               return 1;
+         }
+
+         else if (global->skip >= SKIP_UNSAFE)
+            return 1;
+
+         return 0;
+   }
+}
+
+/* PER-FILE CONTROL STRUCTURE */
+struct chunk;
+struct IDAT;
+struct file
+{
+   /* ANCESTORS */
+   struct global *global;
+
+   /* PUBLIC PER-FILE VARIABLES: CALLER INITIALIZE */
+   const char *   file_name;
+   const char *   out_name;      /* Name of output file (if required) */
+
+   /* PUBLIC PER-FILE VARIABLES: SET BY PNG READ CODE */
+   /* File specific result codes */
+   int            status_code;   /* Set to a bit mask of the following: */
+   int            read_errno;    /* Records a read error errno */
+   int            write_errno;   /* Records a write error errno */
+
+   /* IHDR information */
+   png_uint_32    width;
+   png_uint_32    height;
+   png_byte       bit_depth;
+   png_byte       color_type;
+   png_byte       compression_method;
+   png_byte       filter_method;
+   png_byte       interlace_method;
+
+   udigit         image_bytes[5];
+   int            image_digits;
+
+   /* PROTECTED PER-FILE VARIABLES: USED BY THE READ CODE */
+   FILE *         file;          /* Original PNG file */
+   FILE *         out;           /* If a new one is being written */
+   jmp_buf        jmpbuf;        /* Set while reading a PNG */
+
+   /* PROTECTED CHUNK SPECIFIC VARIABLES: USED BY CHUNK CODE */
+   /* The following variables are used during reading to record the length, type
+    * and data position of the *next* chunk or, right at the start, the
+    * signature (in length,type).
+    *
+    * When a chunk control structure is instantiated these values are copied
+    * into the structure and can then be overritten with the data for the next
+    * chunk.
+    */
+   fpos_t         data_pos;      /* Position of first byte of chunk data */
+   png_uint_32    length;        /* First word (length or signature start) */
+   png_uint_32    type;          /* Second word (type or signature end) */
+   png_uint_32    crc;           /* Running chunk CRC (used by read_chunk) */
+
+   /* These counts are maintained by the read and write routines below and are
+    * reset by the chunk handling code.  They record the total number of bytes
+    * read or written for the chunk, including the header (length,type) bytes.
+    */
+   png_uint_32    read_count;    /* Count of bytes read (in the chunk) */
+   png_uint_32    write_count;   /* Count of bytes written (in the chunk) */
+   int            state;         /* As defined here: */
+#     define STATE_SIGNATURE  0  /* The signature is being written */
+#     define STATE_CHUNKS     1  /* Non-IDAT chunks are being written */
+#     define STATE_IDAT       2  /* An IDAT stream is being written */
+
+   /* Two pointers used to enable clean-up in the event of fatal errors and to
+    * hold state about the parser process (only one of each at present.)
+    */
+   struct chunk * chunk;
+   struct IDAT *  idat;
+
+   /* Interface to allocate a new chunk or IDAT control structure.  The result
+    * is returned by setting one or other of the above variables.  Note that the
+    * relevant initializer is called by the allocator function.  The alloc_ptr
+    * is used only by the implementation of the allocate function.
+    */
+   void *         alloc_ptr;
+   void         (*alloc)(struct file*,int idat);
+                                  /* idat: allocate IDAT not chunk */
+};
+
+/* Valid longjmp (stop) codes are: */
+#define LIBPNG_WARNING_CODE   1 /* generic png_error */
+#define LIBPNG_ERROR_CODE     2 /* generic png_error */
+#define ZLIB_ERROR_CODE       3 /* generic zlib error */
+#define INVALID_ERROR_CODE    4 /* detected an invalid PNG */
+#define READ_ERROR_CODE       5 /* read failed */
+#define WRITE_ERROR_CODE      6 /* error in write */
+#define UNEXPECTED_ERROR_CODE 7 /* unexpected (internal?) error */
+
+static void
+emit_string(const char *str, FILE *out)
+   /* Print a string with spaces replaced by '_' and non-printing characters by
+    * an octal escape.
+    */
+{
+   for (; *str; ++str)
+      if (isgraph(UCHAR_MAX & *str))
+         putc(*str, out);
+
+      else if (isspace(UCHAR_MAX & *str))
+         putc('_', out);
+
+      else
+         fprintf(out, "\\%.3o", *str);
+}
+
+static const char *
+strcode(int code)
+{
+   switch (code)
+   {
+      case LIBPNG_WARNING_CODE:   return "warning";
+      case LIBPNG_ERROR_CODE:     return "libpng";
+      case ZLIB_ERROR_CODE:       return "zlib";
+      case INVALID_ERROR_CODE:    return "invalid";
+      case READ_ERROR_CODE:       return "read";
+      case WRITE_ERROR_CODE:      return "write";
+      case UNEXPECTED_ERROR_CODE: return "unexpected";
+      default:                    return "INVALID";
+   }
+}
+
+static void
+emit_error(struct file *file, int code, const char *what)
+   /* Generic error message routine, takes a 'stop' code but can be used
+    * elsewhere.  Always outputs a message.
+    */
+{
+   const char *reason;
+   int err = 0;
+
+   switch (code)
+   {
+      case LIBPNG_WARNING_CODE:   reason = "libpng warning:"; break;
+      case LIBPNG_ERROR_CODE:     reason = "libpng error:"; break;
+      case ZLIB_ERROR_CODE:       reason = "zlib error:"; break;
+      case INVALID_ERROR_CODE:    reason = "invalid"; break;
+      case READ_ERROR_CODE:       reason = "read failure:";
+                                  err = file->read_errno;
+                                  break;
+      case WRITE_ERROR_CODE:      reason = "write error";
+                                  err = file->write_errno;
+                                  break;
+      case UNEXPECTED_ERROR_CODE: reason = "unexpected error:";
+                                  err = file->read_errno;
+                                  if (err == 0)
+                                     err = file->write_errno;
+                                  break;
+      default:                    reason = "INVALID (internal error):"; break;
+   }
+
+   if (err != 0)
+      fprintf(stderr, "%s: %s %s [%s]\n", file->file_name, reason, what,
+         strerror(err));
+
+   else
+      fprintf(stderr, "%s: %s %s\n", file->file_name, reason, what);
+}
+
+static void chunk_end(struct chunk **);
+static void IDAT_end(struct IDAT **);
+
+static int
+file_end(struct file *file)
+{
+   int rc;
+
+   /* If either of the chunk pointers are set end them here, the IDAT structure
+    * must be deallocated first as it may deallocate the chunk structure.
+    */
+   if (file->idat != NULL)
+      IDAT_end(&file->idat);
+
+   if (file->chunk != NULL)
+      chunk_end(&file->chunk);
+
+   rc = file->status_code;
+
+   if (file->file != NULL)
+      (void)fclose(file->file);
+
+   if (file->out != NULL)
+   {
+      /* NOTE: this is bitwise |, all the following functions must execute and
+       * must succeed.
+       */
+      if (ferror(file->out) | fflush(file->out) | fclose(file->out))
+      {
+         perror(file->out_name);
+         emit_error(file, READ_ERROR_CODE, "output write error");
+         rc |= WRITE_ERROR;
+      }
+   }
+
+   /* Accumulate the result codes */
+   file->global->status_code |= rc;
+
+   CLEAR(*file);
+
+   return rc; /* status code: non-zero on read or write error */
+}
+
+static int
+file_init(struct file *file, struct global *global, const char *file_name,
+   const char *out_name, void *alloc_ptr, void (*alloc)(struct file*,int))
+   /* Initialize a file control structure.  This will open the given files as
+    * well.  The status code returned is 0 on success, non zero (using the flags
+    * above) on a file open error.
+    */
+{
+   CLEAR(*file);
+   file->global = global;
+
+   file->file_name = file_name;
+   file->out_name = out_name;
+   file->status_code = 0;
+   file->read_errno = 0;
+   file->write_errno = 0;
+
+   file->file = NULL;
+   file->out = NULL;
+   /* jmpbuf is garbage: must be set by read_png */
+
+   file->read_count = 0;
+   file->state = STATE_SIGNATURE;
+
+   file->chunk = NULL;
+   file->idat = NULL;
+
+   file->alloc_ptr = alloc_ptr;
+   file->alloc = alloc;
+
+   /* Open the files: */
+   assert(file_name != NULL);
+   file->file = fopen(file_name, "rb");
+
+   if (file->file == NULL)
+   {
+      file->read_errno = errno;
+      file->status_code |= FILE_ERROR;
+      /* Always output: please give a readable file! */
+      perror(file_name);
+      return FILE_ERROR;
+   }
+
+   if (out_name != NULL)
+   {
+      file->out = fopen(out_name, "wb");
+
+      if (file->out == NULL)
+      {
+         file->write_errno = errno;
+         file->status_code |= WRITE_ERROR;
+         perror(out_name);
+         return WRITE_ERROR;
+      }
+   }
+
+   return 0;
+}
+
+static void
+log_error(struct file *file, int code, const char *what)
+   /* Like emit_error but checks the global 'errors' flag */
+{
+   if (file->global->errors)
+      emit_error(file, code, what);
+}
+
+static char
+type_char(png_uint_32 v)
+{
+   /* In fact because chunk::chunk_type is validated prior to any call to this
+    * function it will always return a-zA-Z, but the extra codes are just there
+    * to help in finding internal (programming) errors.  Note that the code only
+    * ever considers the low 7 bits of the value (so it is not necessary for the
+    * type_name function to mask of the byte.)
+    */
+   if (v & 32)
+      return "!abcdefghijklmnopqrstuvwxyz56789"[(v-96)&31];
+
+   else
+      return "@ABCDEFGHIJKLMNOPQRSTUVWXYZ01234"[(v-64)&31];
+}
+
+static void
+type_name(png_uint_32 type, FILE *out)
+{
+   putc(type_char(type >> 24), out);
+   putc(type_char(type >> 16), out);
+   putc(type_char(type >>  8), out);
+   putc(type_char(type      ), out);
+}
+
+static void
+type_sep(FILE *out)
+{
+   putc(':', out);
+   putc(' ', out);
+}
+
+static png_uint_32 current_type(struct file *file, int code);
+
+PNG_NORETURN static void
+stop(struct file *file, int code, const char *what)
+   /* Return control when a PNG file cannot be read. This outputs an 'ERR'
+    * summary line too.
+    */
+{
+   log_error(file, code, what);
+
+   /* The chunk being read is typically identified by file->chunk or, if this is
+    * NULL, by file->type.  This may be wrong if libpng reads ahead, but this
+    * only happens with IDAT where libpng reads the header then jumps around
+    * finding errors in the previous chunks.  We know that is happening because
+    * we are at the start of the IDAT (i.e. no IDAT data has yet been written.)
+    *
+    * SUMMARY FORMAT (stop):
+    *
+    * IDAT ERR status code read-errno write-errno message file
+    *
+    * 'uncompressed' will be 0 if there was a problem in the IHDR.  The errno
+    * values are emit_string(strerror(errno)).
+    */
+   if (file->global->quiet < 2) /* need two quiets to stop this. */
+   {
+      png_uint_32 type;
+
+      if (file->chunk != NULL)
+         type = current_type(file, code); /* Gropes in struct chunk and IDAT */
+
+      else
+         type = file->type;
+
+      if (type)
+         type_name(type, stdout);
+
+      else /* magic: an IDAT header, produces bogons for too many IDATs */
+         fputs("HEAD", stdout); /* not a registered chunk! */
+
+      printf(" ERR %.2x %s ", file->status_code, strcode(code));
+      /* This only works one strerror at a time, because of the way strerror is
+       * implemented.
+       */
+      emit_string(strerror(file->read_errno), stdout);
+      putc(' ', stdout);
+      emit_string(strerror(file->write_errno), stdout);
+      putc(' ', stdout);
+      emit_string(what, stdout);
+      putc(' ', stdout);
+      fputs(file->file_name, stdout);
+      putc('\n', stdout);
+   }
+
+   file->status_code |= FILE_ERROR;
+   longjmp(file->jmpbuf, code);
+}
+
+PNG_NORETURN static void
+stop_invalid(struct file *file, const char *what)
+{
+   stop(file, INVALID_ERROR_CODE, what);
+}
+
+static void
+type_message(struct file *file, png_uint_32 type, const char *what)
+   /* Error message for a chunk; the chunk name comes from 'type' */
+{
+   if (file->global->errors)
+   {
+      fputs(file->file_name, stderr);
+      type_sep(stderr);
+      type_name(type, stderr);
+      type_sep(stderr);
+      fputs(what, stderr);
+      putc('\n', stderr);
+   }
+}
+
+/* Input file positioning - we jump around in the input file while reading
+ * stuff, these wrappers deal with the error handling.
+ */
+static void
+file_getpos(struct file *file, fpos_t *pos)
+{
+   if (fgetpos(file->file, pos))
+   {
+      /* This is unexpected, so perror it */
+      perror(file->file_name);
+      stop(file, READ_ERROR_CODE, "fgetpos");
+   }
+}
+
+static void
+file_setpos(struct file *file, const fpos_t *pos)
+{
+   if (fsetpos(file->file, pos))
+   {
+      perror(file->file_name);
+      stop(file, READ_ERROR_CODE, "fsetpos");
+   }
+}
+
+static void
+getpos(struct file *file)
+   /* Get the current position and store it in 'data_pos'.  The corresponding
+    * setpos() function is chunk specific because it uses the copy of the
+    * position for the specific chunk.
+    */
+{
+   file_getpos(file, &file->data_pos);
+}
+
+
+/* Read utility - read a single byte, returns a value in the range 0..255 or EOF
+ * on a read error.  In the latter case status_code and read_errno are updated
+ * appropriately.
+ */
+static int
+read_byte(struct file *file)
+{
+   int ch = getc(file->file);
+
+   if (ch >= 0 && ch <= 255)
+   {
+      ++(file->read_count);
+      return ch;
+   }
+
+   else if (ch != EOF)
+   {
+      file->status_code |= INTERNAL_ERROR;
+      file->read_errno = ERANGE; /* out of range character */
+
+      /* This is very unexpected; an error message is always output: */
+      emit_error(file, UNEXPECTED_ERROR_CODE, "file read");
+   }
+
+#  ifdef EINTR
+      else if (errno == EINTR) /* Interrupted, try again */
+      {
+         errno = 0;
+         return read_byte(file);
+      }
+#  endif
+
+   else
+   {
+      /* An error, it doesn't really matter what the error is but it gets
+       * recorded anyway.
+       */
+      if (ferror(file->file))
+         file->read_errno = errno;
+
+      else if (feof(file->file))
+         file->read_errno = 0; /* I.e. a regular EOF, no error */
+
+      else /* unexpected */
+         file->read_errno = EDOM;
+   }
+
+   /* 'TRUNCATED' is used for all cases of failure to read a byte, because of
+    * the way libpng works a byte read is never attempted unless the byte is
+    * expected to be there, so EOF should not occur.
+    */
+   file->status_code |= TRUNCATED;
+   return EOF;
+}
+
+static png_byte
+reread_byte(struct file *file)
+   /* Read a byte when an error is not expected to happen because the byte has
+    * been read before without error.
+    */
+{
+   int ch = getc(file->file);
+
+   if (errno != 0)
+      file->read_errno = errno;
+
+   if (ch < 0 || ch > 255)
+      stop(file, UNEXPECTED_ERROR_CODE, "reread");
+
+   return (png_byte)ch;
+}
+
+static png_uint_32
+reread_4(struct file *file)
+   /* The same but for a four byte quantity */
+{
+   png_uint_32 result = 0;
+   int i = 0;
+
+   while (++i <= 4)
+      result = (result << 8) + reread_byte(file);
+
+   return result;
+}
+
+static void
+skip_12(struct file *file)
+   /* Skip exactly 12 bytes in the input stream - used to skip a CRC and chunk
+    * header that has been read before.
+    */
+{
+   /* Since the chunks were read before this shouldn't fail: */
+   if (fseek(file->file, 12, SEEK_CUR) != 0)
+   {
+      if (errno != 0)
+         file->read_errno = errno;
+
+      stop(file, UNEXPECTED_ERROR_CODE, "reskip");
+   }
+}
+
+static void
+write_byte(struct file *file, int b)
+   /* Write one byte to the output - this causes a fatal error if the write
+    * fails and the read of this PNG file immediately terminates.  Just
+    * increments the write count if there is no output file.
+    */
+{
+   if (file->out != NULL)
+   {
+      if (putc(b, file->out) != b)
+      {
+         file->write_errno = errno;
+         file->status_code |= WRITE_ERROR;
+         stop(file, WRITE_ERROR_CODE, "write byte");
+      }
+   }
+
+   ++(file->write_count);
+}
+
+/* Derivatives of the read/write functions. */
+static unsigned int
+read_4(struct file *file, png_uint_32 *pu)
+   /* Read four bytes, returns the number of bytes read successfully and, if all
+    * four bytes are read, assigns the result to *pu.
+    */
+{
+   unsigned int i = 0;
+   png_uint_32 val = 0;
+
+   do
+   {
+      int ch = read_byte(file);
+
+      if (ch == EOF)
+         return i;
+
+      val = (val << 8) + ch;
+   } while (++i < 4);
+
+   *pu = val;
+   return i;
+}
+
+/* CRC handling - read but calculate the CRC while doing so. */
+static int
+crc_read_many(struct file *file, png_uint_32 length)
+   /* Reads 'length' bytes and updates the CRC, returns true on success, false
+    * if the input is truncated.
+    */
+{
+   if (length > 0)
+   {
+      png_uint_32 crc = file->crc;
+
+      do
+      {
+         int ch = read_byte(file);
+
+         if (ch == EOF)
+            return 0; /* Truncated */
+
+         crc = crc_one_byte(crc, ch);
+      }
+      while (--length > 0);
+
+      file->crc = crc;
+   }
+
+   return 1; /* OK */
+}
+
+static int
+calc_image_size(struct file *file)
+   /* Fill in the image_bytes field given the IHDR information, calls stop on
+    * error.
+    */
+{
+   png_uint_16 pd = file->bit_depth;
+
+   switch (file->color_type)
+   {
+      default:
+         stop_invalid(file, "IHDR: colour type");
+
+      invalid_bit_depth:
+         stop_invalid(file, "IHDR: bit depth");
+
+      case 0: /* g */
+         if (pd != 1 && pd != 2 && pd != 4 && pd != 8 && pd != 16)
+            goto invalid_bit_depth;
+         break;
+
+      case 3:
+         if (pd != 1 && pd != 2 && pd != 4 && pd != 8)
+            goto invalid_bit_depth;
+         break;
+
+      case 2: /* rgb */
+         if (pd != 8 && pd != 16)
+            goto invalid_bit_depth;
+
+         pd = (png_uint_16)(pd * 3);
+         break;
+
+      case 4: /* ga */
+         if (pd != 8 && pd != 16)
+            goto invalid_bit_depth;
+
+         pd = (png_uint_16)(pd * 2);
+         break;
+
+      case 6: /* rgba */
+         if (pd != 8 && pd != 16)
+            goto invalid_bit_depth;
+
+         pd = (png_uint_16)(pd * 4);
+         break;
+   }
+
+   if (file->width < 1 || file->width > 0x7fffffff)
+      stop_invalid(file, "IHDR: width");
+
+   else if (file->height < 1 || file->height > 0x7fffffff)
+      stop_invalid(file, "IHDR: height");
+
+   else if (file->compression_method != 0)
+      stop_invalid(file, "IHDR: compression method");
+
+   else if (file->filter_method != 0)
+      stop_invalid(file, "IHDR: filter method");
+
+   else switch (file->interlace_method)
+   {
+      case PNG_INTERLACE_ADAM7:
+         /* Interlacing makes the image larger because of the replication of
+          * both the filter byte and the padding to a byte boundary.
+          */
+         {
+            int pass;
+            int image_digits = 0;
+            udigit row_width[2], row_bytes[3];
+
+            for (pass=0; pass<=6; ++pass)
+            {
+               png_uint_32 pw = PNG_PASS_COLS(file->width, pass);
+
+               if (pw > 0)
+               {
+                  int  digits;
+
+                  /* calculate 1+((pw*pd+7)>>3) in row_bytes */
+                  digits = uarb_mult_digit(row_bytes, uarb_set(row_bytes, 7),
+                     row_width, uarb_set(row_width, pw), pd);
+                  digits = uarb_shift(row_bytes, digits, 3);
+                  digits = uarb_inc(row_bytes, digits, 1);
+
+                  /* Add row_bytes * pass-height to the file image_bytes field
+                   */
+                  image_digits = uarb_mult32(file->image_bytes, image_digits,
+                     row_bytes, digits,
+                     PNG_PASS_ROWS(file->height, pass));
+               }
+            }
+
+            file->image_digits = image_digits;
+         }
+         break;
+
+      case PNG_INTERLACE_NONE:
+         {
+            int  digits;
+            udigit row_width[2], row_bytes[3];
+
+            /* As above, but use image_width in place of the pass width: */
+            digits = uarb_mult_digit(row_bytes, uarb_set(row_bytes, 7),
+               row_width, uarb_set(row_width, file->width), pd);
+            digits = uarb_shift(row_bytes, digits, 3);
+            digits = uarb_inc(row_bytes, digits, 1);
+
+            /* Set row_bytes * image-height to the file image_bytes field */
+            file->image_digits = uarb_mult32(file->image_bytes, 0,
+               row_bytes, digits, file->height);
+         }
+         break;
+
+      default:
+         stop_invalid(file, "IHDR: interlace method");
+   }
+
+   assert(file->image_digits >= 1 && file->image_digits <= 5);
+   return 1;
+}
+
+/* PER-CHUNK CONTROL STRUCTURE
+ * This structure is instantiated for each chunk, except for the IDAT chunks
+ * where one chunk control structure is used for the whole of a single stream of
+ * IDAT chunks (see the IDAT control structure below).
+ */
+struct chunk
+{
+   /* ANCESTORS */
+   struct file *         file;
+   struct global *       global;
+
+   /* PUBLIC IDAT INFORMATION: SET BY THE ZLIB CODE */
+   udigit         uncompressed_bytes[5];
+   int            uncompressed_digits;
+   udigit         compressed_bytes[5];
+   int            compressed_digits;
+
+   /* PUBLIC PER-CHUNK INFORMATION: USED BY CHUNK READ CODE */
+   /* This information is filled in by chunk_init from the data in the file
+    * control structure, but chunk_length may be changed later.
+    */
+   fpos_t         chunk_data_pos;    /* Position of first byte of chunk data */
+   png_uint_32    chunk_length;      /* From header (or modified below) */
+   png_uint_32    chunk_type;        /* From header */
+
+   /* PUBLIC PER-CHUNK INFORMATION: FOR THE CHUNK WRITE CODE */
+   png_uint_32    write_crc;         /* Output CRC (may differ from read_crc) */
+   png_uint_32    rewrite_offset;    /* Count of bytes before rewrite. */
+   int            rewrite_length;    /* Number of bytes left to change */
+   png_byte       rewrite_buffer[2]; /* Buffer of new byte values */
+};
+
+static void
+chunk_message(struct chunk *chunk, const char *message)
+{
+   type_message(chunk->file, chunk->chunk_type, message);
+}
+
+static void
+chunk_end(struct chunk **chunk_var)
+{
+   struct chunk *chunk = *chunk_var;
+
+   *chunk_var = NULL;
+   CLEAR(*chunk);
+}
+
+static void
+chunk_init(struct chunk * const chunk, struct file * const file)
+   /* When a chunk is initialized the file length/type/pos are copied into the
+    * corresponding chunk fields and the new chunk is registered in the file
+    * structure.  There can only be one chunk at a time.
+    *
+    * NOTE: this routine must onely be called from the file alloc routine!
+    */
+{
+   assert(file->chunk == NULL);
+
+   CLEAR(*chunk);
+
+   chunk->file = file;
+   chunk->global = file->global;
+
+   chunk->chunk_data_pos = file->data_pos;
+   chunk->chunk_length = file->length;
+   chunk->chunk_type = file->type;
+
+   /* Compresssed/uncompressed size information (from the zlib control structure
+    * that is used to check the compressed data in a chunk.)
+    */
+   chunk->uncompressed_digits = 0;
+   chunk->compressed_digits = 0;
+
+   file->chunk = chunk;
+}
+
+static png_uint_32
+current_type(struct file *file, int code)
+   /* Guess the actual chunk type that causes a stop() */
+{
+   /* This may return png_IDAT for errors detected (late) in the header; that
+    * includes any inter-chunk consistency check that libpng performs.  Assume
+    * that if the chunk_type is png_IDAT and the file write count is 8 this is
+    * what is happening.
+    */
+   if (file->chunk != NULL)
+   {
+      png_uint_32 type = file->chunk->chunk_type;
+
+      /* This is probably wrong for the excess IDATs case, because then libpng
+       * whines about too many of them (apparently in some cases erroneously)
+       * when the header is read.
+       */
+      if (code <= LIBPNG_ERROR_CODE && type == png_IDAT &&
+         file->write_count == 8)
+         type = 0; /* magic */
+
+      return type;
+   }
+
+   else
+      return file->type;
+}
+
+static void
+setpos(struct chunk *chunk)
+   /* Reset the position to 'chunk_data_pos' - the start of the data for this
+    * chunk.  As a side effect the read_count in the file is reset to 8, just
+    * after the length/type header.
+    */
+{
+   chunk->file->read_count = 8;
+   file_setpos(chunk->file, &chunk->chunk_data_pos);
+}
+
+/* Specific chunk handling - called for each chunk header, all special chunk
+ * processing is initiated in these functions.
+ */
+/* The next functions handle special processing for those chunks with LZ data,
+ * the data is identified and checked for validity.  If there are problems which
+ * cannot be corrected the routines return false, otherwise true (although
+ * modification to the zlib header may be required.)
+ *
+ * The compressed data is in zlib format (RFC1950) and consequently has a
+ * minimum length of 7 bytes.
+ */
+static int zlib_check(struct file *file, png_uint_32 offset);
+
+static int
+process_zTXt_iCCP(struct file *file)
+   /* zTXt and iCCP have exactly the same form - keyword, null, compression
+    * method then compressed data.
+    */
+{
+   struct chunk *chunk = file->chunk;
+   png_uint_32 length;
+   png_uint_32 index = 0;
+
+   assert(chunk != NULL && file->idat == NULL);
+   length = chunk->chunk_length;
+   setpos(chunk);
+
+   while (length >= 9)
+   {
+      --length;
+      ++index;
+      if (reread_byte(file) == 0) /* keyword null terminator */
+      {
+         --length;
+         ++index;
+         (void)reread_byte(file); /* compression method */
+         return zlib_check(file, index);
+      }
+   }
+
+   chunk_message(chunk, "too short");
+   return 0; /* skip */
+}
+
+static int
+process_iTXt(struct file *file)
+{
+   /* Like zTXt but more fields. */
+   struct chunk *chunk = file->chunk;
+   png_uint_32 length;
+   png_uint_32 index = 0;
+
+   assert(chunk != NULL && file->idat == NULL);
+   length = chunk->chunk_length;
+   setpos(chunk);
+
+   while (length >= 5)
+   {
+      --length;
+      ++index;
+      if (reread_byte(file) == 0) /* keyword null terminator */
+      {
+         --length;
+         ++index;
+         if (reread_byte(file) == 0) /* uncompressed text */
+            return 1; /* nothing to check */
+
+         --length;
+         ++index;
+         (void)reread_byte(file); /* compression method */
+
+         /* Skip the language tag (null terminated). */
+         while (length >= 9)
+         {
+            --length;
+            ++index;
+            if (reread_byte(file) == 0) /* terminator */
+            {
+               /* Skip the translated keyword */
+               while (length >= 8)
+               {
+                  --length;
+                  ++index;
+                  if (reread_byte(file) == 0) /* terminator */
+                     return zlib_check(file, index);
+               }
+            }
+         }
+
+         /* Ran out of bytes in the compressed case. */
+         break;
+      }
+   }
+
+   log_error(file, INVALID_ERROR_CODE, "iTXt chunk length");
+
+   return 0; /* skip */
+}
+
+/* IDAT READ/WRITE CONTROL STRUCTURE */
+struct IDAT
+{
+   /* ANCESTORS */
+   struct file *         file;
+   struct global *       global;
+
+   /* PROTECTED IDAT INFORMATION: SET BY THE IDAT READ CODE */
+   struct IDAT_list *idat_list_head; /* START of the list of IDAT information */
+   struct IDAT_list *idat_list_tail; /* *END* of the list of IDAT information */
+
+   /* PROTECTED IDAT INFORMATION: USED BY THE IDAT WRITE CODE */
+   struct IDAT_list *idat_cur;       /* Current list entry */
+   unsigned int      idat_count;     /* And the *current* index into the list */
+   png_uint_32       idat_index;     /* Index of *next* input byte to write */
+   png_uint_32       idat_length;    /* Cache of current chunk length */
+};
+
+/* NOTE: there is currently no IDAT_reset, so a stream cannot contain more than
+ * one IDAT sequence (i.e. MNG is not supported).
+ */
+
+static void
+IDAT_end(struct IDAT **idat_var)
+{
+   struct IDAT *idat = *idat_var;
+   struct file *file = idat->file;
+
+   *idat_var = NULL;
+
+   CLEAR(*idat);
+
+   assert(file->chunk != NULL);
+   chunk_end(&file->chunk);
+
+   /* Regardless of why the IDAT was killed set the state back to CHUNKS (it may
+    * already be CHUNKS because the state isn't changed until process_IDAT
+    * returns; a stop will cause IDAT_end to be entered in state CHUNKS!)
+    */
+   file->state = STATE_CHUNKS;
+}
+
+static void
+IDAT_init(struct IDAT * const idat, struct file * const file)
+   /* When the chunk is png_IDAT instantiate an IDAT control structure in place
+    * of a chunk control structure.  The IDAT will instantiate a chunk control
+    * structure using the file alloc routine.
+    *
+    * NOTE: this routine must only be called from the file alloc routine!
+    */
+{
+   assert(file->chunk == NULL);
+   assert(file->idat == NULL);
+
+   CLEAR(*idat);
+
+   idat->file = file;
+   idat->global = file->global;
+
+   /* Initialize the tail to the pre-allocated buffer and set the count to 0
+    * (empty.)
+    */
+   idat->global->idat_cache.count = 0;
+   idat->idat_list_head = idat->idat_list_tail = &idat->global->idat_cache;
+
+   /* Now the chunk.  The allocator calls the initializer of the new chunk and
+    * stores the result in file->chunk:
+    */
+   file->alloc(file, 0/*chunk*/);
+   assert(file->chunk != NULL);
+
+   /* And store this for cleanup (and to check for double alloc or failure to
+    * free.)
+    */
+   file->idat = idat;
+}
+
+static png_uint_32
+rechunk_length(struct IDAT *idat, int start)
+   /* Return the length for the next IDAT chunk, taking into account
+    * rechunking.
+    */
+{
+   png_uint_32 len = idat->global->idat_max;
+
+   if (len == 0) /* use original chunk lengths */
+   {
+      const struct IDAT_list *cur;
+      unsigned int count;
+
+      if (start)
+         return idat->idat_length; /* use the cache */
+
+      /* Otherwise rechunk_length is called at the end of a chunk for the length
+       * of the next one.
+       */
+      cur = idat->idat_cur;
+      count = idat->idat_count;
+
+      assert(idat->idat_index == idat->idat_length &&
+         idat->idat_length == cur->lengths[count]);
+
+      /* Return length of the *next* chunk */
+      if (++count < cur->count)
+         return cur->lengths[count];
+
+      /* End of this list */
+      assert(cur != idat->idat_list_tail);
+      cur = cur->next;
+      assert(cur != NULL && cur->count > 0);
+      return cur->lengths[0];
+   }
+
+   else /* rechunking */
+   {
+      /* The chunk size is the lesser of file->idat_max and the number
+       * of remaining bytes.
+       */
+      png_uint_32 have = idat->idat_length - idat->idat_index;
+
+      if (len > have)
+      {
+         struct IDAT_list *cur = idat->idat_cur;
+         unsigned int j = idat->idat_count+1; /* the next IDAT in the list */
+
+         do
+         {
+            /* Add up the remaining bytes.  This can't overflow because the
+             * individual lengths are always <= 0x7fffffff, so when we add two
+             * of them overflow is not possible.
+             */
+            assert(cur != NULL);
+
+            for (;;)
+            {
+               /* NOTE: IDAT_list::count here, not IDAT_list::length */
+               for (; j < cur->count; ++j)
+               {
+                  have += cur->lengths[j];
+                  if (len <= have)
+                     return len;
+               }
+
+               /* If this was the end return the count of the available bytes */
+               if (cur == idat->idat_list_tail)
+                  return have;
+
+               cur = cur->next;
+               j = 0;
+            }
+         }
+         while (len > have);
+      }
+
+      return len;
+   }
+}
+
+static int
+process_IDAT(struct file *file)
+   /* Process the IDAT stream, this is the more complex than the preceding
+    * cases because the compressed data is spread across multiple IDAT chunks
+    * (typically).  Rechunking of the data is not handled here; all this
+    * function does is establish whether the zlib header needs to be modified.
+    *
+    * Initially the function returns false, indicating that the chunk should not
+    * be written.  It does this until the last IDAT chunk is passed in, then it
+    * checks the zlib data and returns true.
+    *
+    * It does not return false on a fatal error; it calls stop instead.
+    *
+    * The caller must have an instantiated (IDAT) control structure and it must
+    * have extent over the whole read of the IDAT stream.  For a PNG this means
+    * the whole PNG read, for MNG it could have lesser extent.
+    */
+{
+   struct IDAT_list *list;
+
+   assert(file->idat != NULL && file->chunk != NULL);
+
+   /* We need to first check the entire sequence of IDAT chunks to ensure the
+    * stream is in sync.  Do this by building a list of all the chunks and
+    * recording the length of each because the length may have been fixed up by
+    * sync_stream below.
+    *
+    * At the end of the list of chunks, where the type of the next chunk is not
+    * png_IDAT, process the whole stream using the list data to check validity
+    * then return control to the start and rewrite everything.
+    */
+   list = file->idat->idat_list_tail;
+
+   if (list->count == list->length)
+   {
+      list = IDAT_list_extend(list);
+
+      if (list == NULL)
+         stop(file, READ_ERROR_CODE, "out of memory");
+
+      /* Move to the next block */
+      list->count = 0;
+      file->idat->idat_list_tail = list;
+   }
+
+   /* And fill in the next IDAT information buffer. */
+   list->lengths[(list->count)++] = file->chunk->chunk_length;
+
+   /* The type of the next chunk was recorded in the file control structure by
+    * the caller, if this is png_IDAT return 'skip' to the caller.
+    */
+   if (file->type == png_IDAT)
+      return 0; /* skip this for the moment */
+
+   /* This is the final IDAT chunk, so run the tests to check for the too far
+    * back error and possibly optimize the window bits.  This means going back
+    * to the start of the first chunk data, which is stored in the original
+    * chunk allocation.
+    */
+   setpos(file->chunk);
+
+   if (zlib_check(file, 0))
+   {
+      struct IDAT *idat;
+      int cmp;
+
+      /* The IDAT stream was successfully uncompressed; see whether it
+       * contained the correct number of bytes of image data.
+       */
+      cmp = uarb_cmp(file->image_bytes, file->image_digits,
+         file->chunk->uncompressed_bytes, file->chunk->uncompressed_digits);
+
+      if (cmp < 0)
+         type_message(file, png_IDAT, "extra uncompressed data");
+
+      else if (cmp > 0)
+         stop(file, LIBPNG_ERROR_CODE, "IDAT: uncompressed data too small");
+
+      /* Return the stream to the start of the first IDAT chunk; the length
+       * is set in the write case below but the input chunk variables must be
+       * set (once) here:
+       */
+      setpos(file->chunk);
+
+      idat = file->idat;
+      idat->idat_cur = idat->idat_list_head;
+      idat->idat_length = idat->idat_cur->lengths[0];
+      idat->idat_count = 0; /* Count of chunks read in current list */
+      idat->idat_index = 0; /* Index into chunk data */
+
+      /* Update the chunk length to the correct value for the IDAT chunk: */
+      file->chunk->chunk_length = rechunk_length(idat, 1/*start*/);
+
+      /* Change the state to writing IDAT chunks */
+      file->state = STATE_IDAT;
+
+      return 1;
+   }
+
+   else /* Failure to decompress the IDAT stream; give up. */
+      stop(file, ZLIB_ERROR_CODE, "could not uncompress IDAT");
+}
+
+/* ZLIB CONTROL STRUCTURE */
+struct zlib
+{
+   /* ANCESTORS */
+   struct IDAT *  idat;          /* NOTE: May be NULL */
+   struct chunk * chunk;
+   struct file *  file;
+   struct global *global;
+
+   /* GLOBAL ZLIB INFORMATION: SET BY THE CALLER */
+   png_uint_32    rewrite_offset;
+
+   /* GLOBAL ZLIB INFORMATION: SET BY THE ZLIB READ CODE */
+   udigit         compressed_bytes[5];
+   int            compressed_digits;
+   udigit         uncompressed_bytes[5];
+   int            uncompressed_digits;
+   int            file_bits;             /* window bits from the file */
+   int            ok_bits;               /* Set <16 on a successful read */
+   int            cksum;                 /* Set on a checksum error */
+
+   /* PROTECTED ZLIB INFORMATION: USED BY THE ZLIB ROUTINES */
+   z_stream       z;
+   png_uint_32    extra_bytes;   /* Count of extra compressed bytes */
+   int            state;
+   int            rc;            /* Last return code */
+   int            window_bits;   /* 0 if no change */
+   png_byte       header[2];
+};
+
+static const char *
+zlib_flevel(struct zlib *zlib)
+{
+   switch (zlib->header[1] >> 6)
+   {
+      case 0:  return "supfast";
+      case 1:  return "stdfast";
+      case 2:  return "default";
+      case 3:  return "maximum";
+      default: assert(UNREACHED);
+   }
+
+   return "COMPILER BUG";
+}
+
+static const char *
+zlib_rc(struct zlib *zlib)
+   /* Return a string for the zlib return code */
+{
+   switch (zlib->rc)
+   {
+      case Z_OK:              return "Z_OK";
+      case Z_STREAM_END:      return "Z_STREAM_END";
+      case Z_NEED_DICT:       return "Z_NEED_DICT";
+      case Z_ERRNO:           return "Z_ERRNO";
+      case Z_STREAM_ERROR:    return "Z_STREAM_ERROR";
+      case Z_DATA_ERROR:      return "Z_DATA_ERROR";
+      case Z_MEM_ERROR:       return "Z_MEM_ERROR";
+      case Z_BUF_ERROR:       return "Z_BUF_ERROR";
+      case Z_VERSION_ERROR:   return "Z_VERSION_ERROR";
+      default:                return "Z_*INVALID_RC*";
+   }
+}
+
+static void
+zlib_message(struct zlib *zlib, int unexpected)
+   /* Output a message given a zlib rc */
+{
+   if (zlib->global->errors)
+   {
+      const char *reason = zlib->z.msg;
+
+      if (reason == NULL)
+         reason = "[no message]";
+
+      fputs(zlib->file->file_name, stderr);
+      type_sep(stderr);
+      type_name(zlib->chunk->chunk_type, stderr);
+      fprintf(stderr, ": %szlib error: %d (%s) (%s)\n",
+         unexpected ? "unexpected " : "", zlib->rc, zlib_rc(zlib), reason);
+   }
+}
+
+static void
+zlib_end(struct zlib *zlib)
+{
+   /* Output the summary line now; this ensures a summary line always gets
+    * output regardless of the manner of exit.
+    */
+   if (!zlib->global->quiet)
+   {
+      if (zlib->ok_bits < 16) /* stream was read ok */
+      {
+         const char *reason;
+
+         if (zlib->cksum)
+            reason = "CHK"; /* checksum error */
+
+         else if (zlib->ok_bits > zlib->file_bits)
+            reason = "TFB"; /* fixing a too-far-back error */
+
+         else if (zlib->ok_bits == zlib->file_bits)
+            reason = "OK ";
+
+         else
+            reason = "OPT"; /* optimizing window bits */
+
+         /* SUMMARY FORMAT (for a successful zlib inflate):
+          *
+          * IDAT reason flevel file-bits ok-bits compressed uncompressed file
+          */
+         type_name(zlib->chunk->chunk_type, stdout);
+         printf(" %s %s %d %d ", reason, zlib_flevel(zlib), zlib->file_bits,
+            zlib->ok_bits);
+         uarb_print(zlib->compressed_bytes, zlib->compressed_digits, stdout);
+         putc(' ', stdout);
+         uarb_print(zlib->uncompressed_bytes, zlib->uncompressed_digits,
+            stdout);
+         putc(' ', stdout);
+         fputs(zlib->file->file_name, stdout);
+         putc('\n', stdout);
+      }
+
+      else
+      {
+         /* This is a zlib read error; the chunk will be skipped.  For an IDAT
+          * stream this will also cause a fatal read error (via stop()).
+          *
+          * SUMMARY FORMAT:
+          *
+          * IDAT SKP flevel file-bits z-rc compressed message file
+          *
+          * z-rc is the zlib failure code; message is the error message with
+          * spaces replaced by '-'.  The compressed byte count indicates where
+          * in the zlib stream the error occurred.
+          */
+         type_name(zlib->chunk->chunk_type, stdout);
+         printf(" SKP %s %d %s ", zlib_flevel(zlib), zlib->file_bits,
+            zlib_rc(zlib));
+         uarb_print(zlib->compressed_bytes, zlib->compressed_digits, stdout);
+         putc(' ', stdout);
+         emit_string(zlib->z.msg ? zlib->z.msg : "[no_message]", stdout);
+         putc(' ', stdout);
+         fputs(zlib->file->file_name, stdout);
+         putc('\n', stdout);
+      }
+   }
+
+   if (zlib->state >= 0)
+   {
+      zlib->rc = inflateEnd(&zlib->z);
+
+      if (zlib->rc != Z_OK)
+         zlib_message(zlib, 1/*unexpected*/);
+   }
+
+   CLEAR(*zlib);
+}
+
+static int
+zlib_reset(struct zlib *zlib, int window_bits)
+   /* Reinitializes a zlib with a different window_bits */
+{
+   assert(zlib->state >= 0); /* initialized by zlib_init */
+
+   zlib->z.next_in = Z_NULL;
+   zlib->z.avail_in = 0;
+   zlib->z.next_out = Z_NULL;
+   zlib->z.avail_out = 0;
+
+   zlib->window_bits = window_bits;
+   zlib->compressed_digits = 0;
+   zlib->uncompressed_digits = 0;
+
+   zlib->state = 0; /* initialized, once */
+   zlib->rc = inflateReset2(&zlib->z, 0);
+   if (zlib->rc != Z_OK)
+   {
+      zlib_message(zlib, 1/*unexpected*/);
+      return 0;
+   }
+
+   return 1;
+}
+
+static int
+zlib_init(struct zlib *zlib, struct IDAT *idat, struct chunk *chunk,
+   int window_bits, png_uint_32 offset)
+   /* Initialize a zlib_control; the result is true/false */
+{
+   CLEAR(*zlib);
+
+   zlib->idat = idat;
+   zlib->chunk = chunk;
+   zlib->file = chunk->file;
+   zlib->global = chunk->global;
+   zlib->rewrite_offset = offset; /* never changed for this zlib */
+
+   /* *_out does not need to be set: */
+   zlib->z.next_in = Z_NULL;
+   zlib->z.avail_in = 0;
+   zlib->z.zalloc = Z_NULL;
+   zlib->z.zfree = Z_NULL;
+   zlib->z.opaque = Z_NULL;
+
+   zlib->state = -1;
+   zlib->window_bits = window_bits;
+
+   zlib->compressed_digits = 0;
+   zlib->uncompressed_digits = 0;
+
+   /* These values are sticky across reset (in addition to the stuff in the
+    * first block, which is actually constant.)
+    */
+   zlib->file_bits = 24;
+   zlib->ok_bits = 16; /* unset */
+   zlib->cksum = 0; /* set when a checksum error is detected */
+
+   /* '0' means use the header; inflateInit2 should always succeed because it
+    * does nothing apart from allocating the internal zstate.
+    */
+   zlib->rc = inflateInit2(&zlib->z, 0);
+   if (zlib->rc != Z_OK)
+   {
+      zlib_message(zlib, 1/*unexpected*/);
+      return 0;
+   }
+
+   else
+   {
+      zlib->state = 0; /* initialized */
+      return 1;
+   }
+}
+
+static int
+max_window_bits(uarbc size, int ndigits)
+   /* Return the zlib stream window bits required for data of the given size. */
+{
+   png_uint_16 cb;
+
+   if (ndigits > 1)
+      return 15;
+
+   cb = size[0];
+
+   if (cb > 16384) return 15;
+   if (cb >  8192) return 14;
+   if (cb >  4096) return 13;
+   if (cb >  2048) return 12;
+   if (cb >  1024) return 11;
+   if (cb >   512) return 10;
+   if (cb >   256) return  9;
+   return 8;
+}
+
+static int
+zlib_advance(struct zlib *zlib, png_uint_32 nbytes)
+   /* Read nbytes compressed bytes; the stream will be initialized if required.
+    * Bytes are always being reread and errors are fatal.  The return code is as
+    * follows:
+    *
+    *    -1: saw the "too far back" error
+    *     0: ok, keep going
+    *     1: saw Z_STREAM_END (zlib->extra_bytes indicates too much data)
+    *     2: a zlib error that cannot be corrected (error message already
+    *        output if required.)
+    */
+#  define ZLIB_TOO_FAR_BACK (-1)
+#  define ZLIB_OK           0
+#  define ZLIB_STREAM_END   1
+#  define ZLIB_FATAL        2
+{
+   int state = zlib->state;
+   int endrc = ZLIB_OK;
+   png_uint_32 in_bytes = 0;
+   struct file *file = zlib->file;
+
+   assert(state >= 0);
+
+   while (in_bytes < nbytes && endrc == ZLIB_OK)
+   {
+      png_uint_32 out_bytes;
+      int flush;
+      png_byte bIn = reread_byte(file);
+      png_byte bOut;
+
+      switch (state)
+      {
+         case 0: /* first header byte */
+            {
+               int file_bits = 8+(bIn >> 4);
+               int new_bits = zlib->window_bits;
+
+               zlib->file_bits = file_bits;
+
+               /* Check against the existing value - it may not need to be
+                * changed.  Note that a bogus file_bits is allowed through once,
+                * to see if it works, but the window_bits value is set to 15,
+                * the maximum.
+                */
+               if (new_bits == 0) /* no change */
+                  zlib->window_bits = ((file_bits > 15) ? 15 : file_bits);
+
+               else if (new_bits != file_bits) /* rewrite required */
+                  bIn = (png_byte)((bIn & 0xf) + ((new_bits-8) << 4));
+            }
+
+            zlib->header[0] = bIn;
+            zlib->state = state = 1;
+            break;
+
+         case 1: /* second header byte */
+            {
+               int b2 = bIn & 0xe0; /* top 3 bits */
+
+               /* The checksum calculation, on the first 11 bits: */
+               b2 += 0x1f - ((zlib->header[0] << 8) + b2) % 0x1f;
+
+               /* Update the checksum byte if required: */
+               if (bIn != b2)
+               {
+                  /* If the first byte wasn't changed this indicates an error in
+                   * the checksum calculation; signal this by setting 'cksum'.
+                   */
+                  if (zlib->file_bits == zlib->window_bits)
+                     zlib->cksum = 1;
+
+                  bIn = (png_byte)b2;
+               }
+            }
+
+            zlib->header[1] = bIn;
+            zlib->state = state = 2;
+            break;
+
+         default: /* After the header bytes */
+            break;
+      }
+
+      /* For some streams, perhaps only those compressed with 'superfast
+       * compression' (which results in a lot of copying) Z_BUF_ERROR can happen
+       * immediately after all output has been flushed on the next input byte.
+       * This is handled below when Z_BUF_ERROR is detected by adding an output
+       * byte.
+       */
+      zlib->z.next_in = &bIn;
+      zlib->z.avail_in = 1;
+      zlib->z.next_out = &bOut;
+      zlib->z.avail_out = 0;     /* Initially */
+
+      /* Initially use Z_NO_FLUSH in an attempt to persuade zlib to look at this
+       * byte without confusing what is going on with output.
+       */
+      flush = Z_NO_FLUSH;
+      out_bytes = 0;
+
+      /* NOTE: expression 3 is only evaluated on 'continue', because of the
+       * 'break' at the end of this loop below.
+       */
+      for (;endrc == ZLIB_OK;
+         flush = Z_SYNC_FLUSH,
+         zlib->z.next_out = &bOut,
+         zlib->z.avail_out = 1,
+         ++out_bytes)
+      {
+         zlib->rc = inflate(&zlib->z, flush);
+         out_bytes -= zlib->z.avail_out;
+
+         switch (zlib->rc)
+         {
+            case Z_BUF_ERROR:
+               if (zlib->z.avail_out == 0)
+                  continue; /* Try another output byte. */
+
+               if (zlib->z.avail_in == 0)
+                  break; /* Try another input byte */
+
+               /* Both avail_out and avail_in are 1 yet zlib returned a code
+                * indicating no progress was possible.  This is unexpected.
+                */
+               zlib_message(zlib, 1/*unexpected*/);
+               endrc = ZLIB_FATAL; /* stop processing */
+               break;
+
+            case Z_OK:
+               /* Zlib is supposed to have made progress: */
+               assert(zlib->z.avail_out == 0 || zlib->z.avail_in == 0);
+               continue;
+
+            case Z_STREAM_END:
+               /* This is the successful end. */
+               zlib->state = 3; /* end of stream */
+               endrc = ZLIB_STREAM_END;
+               break;
+
+            case Z_NEED_DICT:
+               zlib_message(zlib, 0/*stream error*/);
+               endrc = ZLIB_FATAL;
+               break;
+
+            case Z_DATA_ERROR:
+               /* The too far back error can be corrected, others cannot: */
+               if (zlib->z.msg != NULL &&
+                  strcmp(zlib->z.msg, "invalid distance too far back") == 0)
+               {
+                  endrc = ZLIB_TOO_FAR_BACK;
+                  break;
+               }
+               /* FALLTHROUGH */
+
+            default:
+               zlib_message(zlib, 0/*stream error*/);
+               endrc = ZLIB_FATAL;
+               break;
+         } /* switch (inflate rc) */
+
+         /* Control gets here when further output is not possible; endrc may
+          * still be ZLIB_OK if more input is required.
+          */
+         break;
+      } /* for (output bytes) */
+
+      /* Keep a running count of output byte produced: */
+      zlib->uncompressed_digits = uarb_add32(zlib->uncompressed_bytes,
+         zlib->uncompressed_digits, out_bytes);
+
+      /* Keep going, the loop will terminate when endrc is no longer set to
+       * ZLIB_OK or all the input bytes have been consumed; meanwhile keep
+       * adding input bytes.
+       */
+      assert(zlib->z.avail_in == 0 || endrc != ZLIB_OK);
+
+      in_bytes += 1 - zlib->z.avail_in;
+   } /* while (input bytes) */
+
+   assert(in_bytes == nbytes || endrc != ZLIB_OK);
+
+   /* Update the running total of input bytes consumed */
+   zlib->compressed_digits = uarb_add32(zlib->compressed_bytes,
+      zlib->compressed_digits, in_bytes - zlib->z.avail_in);
+
+   /* At the end of the stream update the chunk with the accumulated
+    * information if it is an improvement:
+    */
+   if (endrc == ZLIB_STREAM_END && zlib->window_bits < zlib->ok_bits)
+   {
+      struct chunk *chunk = zlib->chunk;
+
+      chunk->uncompressed_digits = uarb_copy(chunk->uncompressed_bytes,
+         zlib->uncompressed_bytes, zlib->uncompressed_digits);
+      chunk->compressed_digits = uarb_copy(chunk->compressed_bytes,
+         zlib->compressed_bytes, zlib->compressed_digits);
+      chunk->rewrite_buffer[0] = zlib->header[0];
+      chunk->rewrite_buffer[1] = zlib->header[1];
+
+      if (zlib->window_bits != zlib->file_bits || zlib->cksum)
+      {
+         /* A rewrite is required */
+         chunk->rewrite_offset = zlib->rewrite_offset;
+         chunk->rewrite_length = 2;
+      }
+
+      else
+      {
+         chunk->rewrite_offset = 0;
+         chunk->rewrite_length = 0;
+      }
+
+      if (in_bytes < nbytes)
+         chunk_message(chunk, "extra compressed data");
+
+      zlib->extra_bytes = nbytes - in_bytes;
+      zlib->ok_bits = zlib->window_bits;
+   }
+
+   return endrc;
+}
+
+static int
+zlib_run(struct zlib *zlib)
+   /* Like zlib_advance but also handles a stream of IDAT chunks. */
+{
+   /* The 'extra_bytes' field is set by zlib_advance if there is extra
+    * compressed data in the chunk it handles (if it sees Z_STREAM_END before
+    * all the input data has been used.)  This function uses the value to update
+    * the correct chunk length, so the problem should only ever be detected once
+    * for each chunk.  zlib_advance outputs the error message, though see the
+    * IDAT specific check below.
+    */
+   zlib->extra_bytes = 0;
+
+   if (zlib->idat != NULL)
+   {
+      struct IDAT_list *list = zlib->idat->idat_list_head;
+      struct IDAT_list *last = zlib->idat->idat_list_tail;
+      int        skip = 0;
+
+      /* 'rewrite_offset' is the offset of the LZ data within the chunk, for
+       * IDAT it should be 0:
+       */
+      assert(zlib->rewrite_offset == 0);
+
+      /* Process each IDAT_list in turn; the caller has left the stream
+       * positioned at the start of the first IDAT chunk data.
+       */
+      for (;;)
+      {
+         unsigned int count = list->count;
+         unsigned int i;
+
+         for (i = 0; i<count; ++i)
+         {
+            int rc;
+
+            if (skip > 0) /* Skip CRC and next IDAT header */
+               skip_12(zlib->file);
+
+            skip = 12; /* for the next time */
+
+            rc = zlib_advance(zlib, list->lengths[i]);
+
+            switch (rc)
+            {
+               case ZLIB_OK: /* keep going */
+                  break;
+
+               case ZLIB_STREAM_END: /* stop */
+                  /* There may be extra chunks; if there are and one of them is
+                   * not zero length output the 'extra data' message.  Only do
+                   * this check if errors are being output.
+                   */
+                  if (zlib->global->errors && zlib->extra_bytes == 0)
+                  {
+                     struct IDAT_list *check = list;
+                     int j = i+1, jcount = count;
+
+                     for (;;)
+                     {
+                        for (; j<jcount; ++j)
+                           if (check->lengths[j] > 0)
+                           {
+                              chunk_message(zlib->chunk,
+                                 "extra compressed data");
+                              goto end_check;
+                           }
+
+                        if (check == last)
+                           break;
+
+                        check = check->next;
+                        jcount = check->count;
+                        j = 0;
+                     }
+                  }
+
+               end_check:
+                  /* Terminate the list at the current position, reducing the
+                   * length of the last IDAT too if required.
+                   */
+                  list->lengths[i] -= zlib->extra_bytes;
+                  list->count = i+1;
+                  zlib->idat->idat_list_tail = list;
+                  /* FALLTHROUGH */
+
+               default:
+                  return rc;
+            }
+         }
+
+         /* At the end of the compressed data and Z_STREAM_END was not seen. */
+         if (list == last)
+            return ZLIB_OK;
+
+         list = list->next;
+      }
+   }
+
+   else
+   {
+      struct chunk *chunk = zlib->chunk;
+      int rc;
+
+      assert(zlib->rewrite_offset < chunk->chunk_length);
+
+      rc = zlib_advance(zlib, chunk->chunk_length - zlib->rewrite_offset);
+
+      /* The extra bytes in the chunk are handled now by adjusting the chunk
+       * length to exclude them; the zlib data is always stored at the end of
+       * the PNG chunk (although clearly this is not necessary.)  zlib_advance
+       * has already output a warning message.
+       */
+      chunk->chunk_length -= zlib->extra_bytes;
+      return rc;
+   }
+}
+
+static int /* global function; not a member function */
+zlib_check(struct file *file, png_uint_32 offset)
+   /* Check the stream of zlib compressed data in either idat (if given) or (if
+    * not) chunk.  In fact it is zlib_run that handles the difference in reading
+    * a single chunk and a list of IDAT chunks.
+    *
+    * In either case the input file must be positioned at the first byte of zlib
+    * compressed data (the first header byte).
+    *
+    * The return value is true on success, including the case where the zlib
+    * header may need to be rewritten, and false on an unrecoverable error.
+    *
+    * In the case of IDAT chunks 'offset' should be 0.
+    */
+{
+   fpos_t start_pos;
+   struct zlib zlib;
+
+   /* Record the start of the LZ data to allow a re-read. */
+   file_getpos(file, &start_pos);
+
+   /* First test the existing (file) window bits: */
+   if (zlib_init(&zlib, file->idat, file->chunk, 0/*window bits*/, offset))
+   {
+      int min_bits, max_bits, rc;
+
+      /* The first run using the existing window bits. */
+      rc = zlib_run(&zlib);
+
+      switch (rc)
+      {
+         case ZLIB_TOO_FAR_BACK:
+            /* too far back error */
+            file->status_code |= TOO_FAR_BACK;
+            min_bits = zlib.window_bits + 1;
+            max_bits = 15;
+            break;
+
+         case ZLIB_STREAM_END:
+            if (!zlib.global->optimize_zlib &&
+               zlib.window_bits == zlib.file_bits && !zlib.cksum)
+            {
+               /* The trivial case where the stream is ok and optimization was
+                * not requested.
+                */
+               zlib_end(&zlib);
+               return 1;
+            }
+
+            max_bits = max_window_bits(zlib.uncompressed_bytes,
+               zlib.uncompressed_digits);
+            if (zlib.ok_bits < max_bits)
+               max_bits = zlib.ok_bits;
+            min_bits = 8;
+
+            /* cksum is set if there is an error in the zlib header checksum
+             * calculation in the original file (and this may be the only reason
+             * a rewrite is required).  We can't rely on the file window bits in
+             * this case, so do the optimization anyway.
+             */
+            if (zlib.cksum)
+               chunk_message(zlib.chunk, "zlib checksum");
+            break;
+
+
+         case ZLIB_OK:
+            /* Truncated stream; unrecoverable, gets converted to ZLIB_FATAL */
+            zlib.z.msg = PNGZ_MSG_CAST("[truncated]");
+            zlib_message(&zlib, 0/*expected*/);
+            /* FALLTHROUGH */
+
+         default:
+            /* Unrecoverable error; skip the chunk; a zlib_message has already
+             * been output.
+             */
+            zlib_end(&zlib);
+            return 0;
+      }
+
+      /* Optimize window bits or fix a too-far-back error.  min_bits and
+       * max_bits have been set appropriately, ok_bits records the bit value
+       * known to work.
+       */
+      while (min_bits < max_bits || max_bits < zlib.ok_bits/*if 16*/)
+      {
+         int test_bits = (min_bits + max_bits) >> 1;
+
+         if (zlib_reset(&zlib, test_bits))
+         {
+            file_setpos(file, &start_pos);
+            rc = zlib_run(&zlib);
+
+            switch (rc)
+            {
+               case ZLIB_TOO_FAR_BACK:
+                  min_bits = test_bits+1;
+                  if (min_bits > max_bits)
+                  {
+                     /* This happens when the stream really is damaged and it
+                      * contains a distance code that addresses bytes before
+                      * the start of the uncompressed data.
+                      */
+                     assert(test_bits == 15);
+
+                     /* Output the error that wasn't output before: */
+                     if (zlib.z.msg == NULL)
+                        zlib.z.msg = PNGZ_MSG_CAST(
+                           "invalid distance too far back");
+                     zlib_message(&zlib, 0/*stream error*/);
+                     zlib_end(&zlib);
+                     return 0;
+                  }
+                  break;
+
+               case ZLIB_STREAM_END: /* success */
+                  max_bits = test_bits;
+                  break;
+
+               default:
+                  /* A fatal error; this happens if a too-far-back error was
+                   * hiding a more serious error, zlib_advance has already
+                   * output a zlib_message.
+                   */
+                  zlib_end(&zlib);
+                  return 0;
+            }
+         }
+
+         else /* inflateReset2 failed */
+         {
+            zlib_end(&zlib);
+            return 0;
+         }
+      }
+
+      /* The loop guarantees this */
+      assert(zlib.ok_bits == max_bits);
+      zlib_end(&zlib);
+      return 1;
+   }
+
+   else /* zlib initialization failed - skip the chunk */
+   {
+      zlib_end(&zlib);
+      return 0;
+   }
+}
+
+/***************************** LIBPNG CALLBACKS *******************************/
+/* The strategy here is to run a regular libpng PNG file read but examine the
+ * input data (from the file) before passing it to libpng so as to be aware of
+ * the state we expect libpng to be in.  Warning and error callbacks are also
+ * intercepted so that they can be quieted and interpreted.  Interpretation
+ * depends on a somewhat risky string match for known error messages; let us
+ * hope that this can be fixed in the next version of libpng.
+ *
+ * The control structure is pointed to by the libpng error pointer.  It contains
+ * that set of structures which must persist across multiple read callbacks,
+ * which is pretty much everything except the 'zlib' control structure.
+ *
+ * The file structure is instantiated in the caller of the per-file routine, but
+ * the per-file routine contains the chunk and IDAT control structures.
+ */
+/* The three routines read_chunk, process_chunk and sync_stream can only be
+ * called via a call to read_chunk and only exit at a return from process_chunk.
+ * These routines could have been written as one confusing large routine,
+ * instead this code relies on the compiler to do tail call elimination.  The
+ * possible calls are as follows:
+ *
+ * read_chunk
+ *    -> sync_stream
+ *       -> process_chunk
+ *    -> process_chunk
+ *       -> read_chunk
+ *       returns
+ */
+static void read_chunk(struct file *file);
+static void
+process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length,
+   png_uint_32 next_type)
+   /* Called when the chunk data has been read, next_length and next_type
+    * will be set for the next chunk (or 0 if this is IEND).
+    *
+    * When this routine returns, chunk_length and chunk_type will be set for the
+    * next chunk to write because if a chunk is skipped this return calls back
+    * to read_chunk.
+    */
+{
+   png_uint_32 type = file->type;
+
+   if (file->global->verbose > 1)
+   {
+      fputs("  ", stderr);
+      type_name(file->type, stderr);
+      fprintf(stderr, " %lu 0x%.8x 0x%.8x\n", (unsigned long)file->length,
+         file->crc ^ 0xffffffff, file_crc);
+   }
+
+   /* The basic structure seems correct but the CRC may not match, in this
+    * case assume that it is simply a bad CRC, either wrongly calculated or
+    * because of damaged stream data.
+    */
+   if ((file->crc ^ 0xffffffff) != file_crc)
+   {
+      /* The behavior is set by the 'skip' setting; if it is anything other
+       * than SKIP_BAD_CRC ignore the bad CRC and return the chunk, with a
+       * corrected CRC and possibly processed, to libpng.  Otherwise skip the
+       * chunk, which will result in a fatal error if the chunk is critical.
+       */
+      file->status_code |= CRC_ERROR;
+
+      /* Ignore the bad CRC  */
+      if (file->global->skip != SKIP_BAD_CRC)
+         type_message(file, type, "bad CRC");
+
+      /* This will cause an IEND with a bad CRC to stop */
+      else if (CRITICAL(type))
+         stop(file, READ_ERROR_CODE, "bad CRC in critical chunk");
+
+      else
+      {
+         type_message(file, type, "skipped: bad CRC");
+
+         /* NOTE: this cannot be reached for IEND because it is critical. */
+         goto skip_chunk;
+      }
+   }
+
+   /* Check for other 'skip' cases and handle these; these only apply to
+    * ancillary chunks (and not tRNS, which should probably have been a critical
+    * chunk.)
+    */
+   if (skip_chunk_type(file->global, type))
+      goto skip_chunk;
+
+   /* The chunk may still be skipped if problems are detected in the LZ data,
+    * however the LZ data check requires a chunk.  Handle this by instantiating
+    * a chunk unless an IDAT is already instantiated (IDAT control structures
+    * instantiate their own chunk.)
+    */
+   if (type != png_IDAT)
+      file->alloc(file, 0/*chunk*/);
+
+   else if (file->idat == NULL)
+      file->alloc(file, 1/*IDAT*/);
+
+   else
+   {
+      /* The chunk length must be updated for process_IDAT */
+      assert(file->chunk != NULL);
+      assert(file->chunk->chunk_type == png_IDAT);
+      file->chunk->chunk_length = file->length;
+   }
+
+   /* Record the 'next' information too, now that the original values for
+    * this chunk have been copied.  Notice that the IDAT chunks only make a
+    * copy of the position of the first chunk, this is fine - process_IDAT does
+    * not need the position of this chunk.
+    */
+   file->length = next_length;
+   file->type = next_type;
+   getpos(file);
+
+   /* Do per-type processing, note that if this code does not return from the
+    * function the chunk will be skipped.  The rewrite is cancelled here so that
+    * it can be set in the per-chunk processing.
+    */
+   file->chunk->rewrite_length = 0;
+   file->chunk->rewrite_offset = 0;
+   switch (type)
+   {
+      default:
+         return;
+
+      case png_IHDR:
+         /* Read this now and update the control structure with the information
+          * it contains.  The header is validated completely to ensure this is a
+          * PNG.
+          */
+         {
+            struct chunk *chunk = file->chunk;
+
+            if (chunk->chunk_length != 13)
+               stop_invalid(file, "IHDR length");
+
+            /* Read all the IHDR information and validate it. */
+            setpos(chunk);
+            file->width = reread_4(file);
+            file->height = reread_4(file);
+            file->bit_depth = reread_byte(file);
+            file->color_type = reread_byte(file);
+            file->compression_method = reread_byte(file);
+            file->filter_method = reread_byte(file);
+            file->interlace_method = reread_byte(file);
+
+            /* This validates all the fields, and calls stop_invalid if
+             * there is a problem.
+             */
+            calc_image_size(file);
+         }
+         return;
+
+         /* Ancillary chunks that require further processing: */
+      case png_zTXt: case png_iCCP:
+         if (process_zTXt_iCCP(file))
+            return;
+         chunk_end(&file->chunk);
+         file_setpos(file, &file->data_pos);
+         break;
+
+      case png_iTXt:
+         if (process_iTXt(file))
+            return;
+         chunk_end(&file->chunk);
+         file_setpos(file, &file->data_pos);
+         break;
+
+      case png_IDAT:
+         if (process_IDAT(file))
+            return;
+         /* First pass: */
+         assert(next_type == png_IDAT);
+         break;
+   }
+
+   /* Control reaches this point if the chunk must be skipped.  For chunks other
+    * than IDAT this means that the zlib compressed data is fatally damanged and
+    * the chunk will not be passed to libpng.  For IDAT it means that the end of
+    * the IDAT stream has not yet been reached and we must handle the next
+    * (IDAT) chunk.  If the LZ data in an IDAT stream cannot be read 'stop' must
+    * be used to halt parsing of the PNG.
+    */
+   read_chunk(file);
+   return;
+
+   /* This is the generic code to skip the current chunk; simply jump to the
+    * next one.
+    */
+skip_chunk:
+   file->length = next_length;
+   file->type = next_type;
+   getpos(file);
+   read_chunk(file);
+}
+
+static png_uint_32
+get32(png_bytep buffer, int offset)
+   /* Read a 32-bit value from an 8-byte circular buffer (used only below).
+    */
+{
+   return
+      (buffer[ offset    & 7] << 24) +
+      (buffer[(offset+1) & 7] << 16) +
+      (buffer[(offset+2) & 7] <<  8) +
+      (buffer[(offset+3) & 7]      );
+}
+
+static void
+sync_stream(struct file *file)
+   /* The stream seems to be messed up, attempt to resync from the current chunk
+    * header.  Executes stop on a fatal error, otherwise calls process_chunk.
+    */
+{
+   png_uint_32 file_crc;
+
+   file->status_code |= STREAM_ERROR;
+
+   if (file->global->verbose)
+   {
+      fputs(" SYNC ", stderr);
+      type_name(file->type, stderr);
+      putc('\n', stderr);
+   }
+
+   /* Return to the start of the chunk data */
+   file_setpos(file, &file->data_pos);
+   file->read_count = 8;
+
+   if (read_4(file, &file_crc) == 4) /* else completely truncated */
+   {
+      /* Ignore the recorded chunk length, proceed through the data looking for
+       * a leading sequence of bytes that match the CRC in the following four
+       * bytes.  Each time a match is found check the next 8 bytes for a valid
+       * length, chunk-type pair.
+       */
+      png_uint_32 length;
+      png_uint_32 type = file->type;
+      png_uint_32 crc = crc_init_4(type);
+      png_byte buffer[8];
+      unsigned int nread = 0, nused = 0;
+
+      for (length=0; length <= 0x7fffffff; ++length)
+      {
+         int ch;
+
+         if ((crc ^ 0xffffffff) == file_crc)
+         {
+            /* A match on the CRC; for IEND this is sufficient, but for anything
+             * else expect a following chunk header.
+             */
+            if (type == png_IEND)
+            {
+               file->length = length;
+               process_chunk(file, file_crc, 0, 0);
+               return;
+            }
+
+            else
+            {
+               /* Need 8 bytes */
+               while (nread < 8+nused)
+               {
+                  ch = read_byte(file);
+                  if (ch == EOF)
+                     goto truncated;
+                  buffer[(nread++) & 7] = (png_byte)ch;
+               }
+
+               /* Prevent overflow */
+               nread -= nused & ~7;
+               nused -= nused & ~7; /* or, nused &= 7 ;-) */
+
+               /* Examine the 8 bytes for a valid chunk header. */
+               {
+                  png_uint_32 next_length = get32(buffer, nused);
+
+                  if (next_length < 0x7fffffff)
+                  {
+                     png_uint_32 next_type = get32(buffer, nused+4);
+
+                     if (chunk_type_valid(next_type))
+                     {
+                        file->read_count -= 8;
+                        process_chunk(file, file_crc, next_length, next_type);
+                        return;
+                     }
+                  }
+
+                  /* Not valid, keep going. */
+               }
+            }
+         }
+
+         /* This catches up with the circular buffer which gets filled above
+          * while checking a chunk header.  This code is slightly tricky - if
+          * the chunk_type is IEND the buffer will never be used, if it is not
+          * the code will always read ahead exactly 8 bytes and pass this on to
+          * process_chunk.  So the invariant that IEND leaves the file position
+          * after the IEND CRC and other chunk leave it after the *next* chunk
+          * header is not broken.
+          */
+         if (nread <= nused)
+         {
+            ch = read_byte(file);
+
+            if (ch == EOF)
+               goto truncated;
+         }
+
+         else
+            ch = buffer[(++nused) & 7];
+
+         crc = crc_one_byte(crc, file_crc >> 24);
+         file_crc = (file_crc << 8) + ch;
+      }
+
+      /* Control gets to here if when 0x7fffffff bytes (plus 8) have been read,
+       * ok, treat this as a damaged stream too:
+       */
+   }
+
+truncated:
+   stop(file, READ_ERROR_CODE, "damaged PNG stream");
+}
+
+static void
+read_chunk(struct file *file)
+   /* On entry file::data_pos must be set to the position of the first byte
+    * of the chunk data *and* the input file must be at this position.  This
+    * routine (via process_chunk) instantiates a chunk or IDAT control structure
+    * based on file::length and file::type and also resets these fields and
+    * file::data_pos for the chunk after this one.  For an IDAT chunk the whole
+    * stream of IDATs will be read, until something other than an IDAT is
+    * encountered, and the file fields will be set for the chunk after the end
+    * of the stream of IDATs.
+    *
+    * For IEND the file::type field will be set to 0, and nothing beyond the end
+    * of the IEND chunk will have been read.
+    */
+{
+   png_uint_32 length = file->length;
+   png_uint_32 type = file->type;
+
+   /* After IEND file::type is set to 0, if libpng attempts to read
+    * more data at this point this is a bug in libpng.
+    */
+   if (type == 0)
+      stop(file, UNEXPECTED_ERROR_CODE, "read beyond IEND");
+
+   if (file->global->verbose > 2)
+   {
+      fputs("   ", stderr);
+      type_name(type, stderr);
+      fprintf(stderr, " %lu\n", (unsigned long)length);
+   }
+
+   /* Start the read_crc calculation with the chunk type, then read to the end
+    * of the chunk data (without processing it in any way) to check that it is
+    * all there and calculate the CRC.
+    */
+   file->crc = crc_init_4(type);
+   if (crc_read_many(file, length)) /* else it was truncated */
+   {
+      png_uint_32 file_crc; /* CRC read from file */
+      unsigned int nread = read_4(file, &file_crc);
+
+      if (nread == 4)
+      {
+         if (type != png_IEND) /* do not read beyond IEND */
+         {
+            png_uint_32 next_length;
+
+            nread += read_4(file, &next_length);
+            if (nread == 8 && next_length <= 0x7fffffff)
+            {
+               png_uint_32 next_type;
+
+               nread += read_4(file, &next_type);
+
+               if (nread == 12 && chunk_type_valid(next_type))
+               {
+                  /* Adjust the read count back to the correct value for this
+                   * chunk.
+                   */
+                  file->read_count -= 8;
+                  process_chunk(file, file_crc, next_length, next_type);
+                  return;
+               }
+            }
+         }
+
+         else /* IEND */
+         {
+            process_chunk(file, file_crc, 0, 0);
+            return;
+         }
+      }
+   }
+
+   /* Control gets to here if the stream seems invalid or damaged in some
+    * way.  Either there was a problem reading all the expected data (this
+    * chunk's data, its CRC and the length and type of the next chunk) or the
+    * next chunk length/type are invalid.  Notice that the cases that end up
+    * here all correspond to cases that would otherwise terminate the read of
+    * the PNG file.
+    */
+   sync_stream(file);
+}
+
+/* This returns a file* from a png_struct in an implementation specific way. */
+static struct file *get_control(png_const_structrp png_ptr);
+
+static void PNGCBAPI
+error_handler(png_structp png_ptr, png_const_charp message)
+{
+   stop(get_control(png_ptr),  LIBPNG_ERROR_CODE, message);
+}
+
+static void PNGCBAPI
+warning_handler(png_structp png_ptr, png_const_charp message)
+{
+   struct file *file = get_control(png_ptr);
+
+   if (file->global->warnings)
+      emit_error(file, LIBPNG_WARNING_CODE, message);
+}
+
+/* Read callback - this is where the work gets done to check the stream before
+ * passing it to libpng
+ */
+static void PNGCBAPI
+read_callback(png_structp png_ptr, png_bytep buffer, size_t count)
+   /* Return 'count' bytes to libpng in 'buffer' */
+{
+   struct file *file = get_control(png_ptr);
+   png_uint_32 type, length; /* For the chunk be *WRITTEN* */
+   struct chunk *chunk;
+
+   /* libpng should always ask for at least one byte */
+   if (count == 0)
+      stop(file, UNEXPECTED_ERROR_CODE, "read callback for 0 bytes");
+
+   /* The callback always reads ahead by 8 bytes - the signature or chunk header
+    * - these bytes are stored in chunk_length and chunk_type.  This block is
+    * executed once for the signature and once for the first chunk right at the
+    * start.
+    */
+   if (file->read_count < 8)
+   {
+      assert(file->read_count == 0);
+      assert((file->status_code & TRUNCATED) == 0);
+
+      (void)read_4(file, &file->length);
+
+      if (file->read_count == 4)
+         (void)read_4(file, &file->type);
+
+      if (file->read_count < 8)
+      {
+         assert((file->status_code & TRUNCATED) != 0);
+         stop(file, READ_ERROR_CODE, "not a PNG (too short)");
+      }
+
+      if (file->state == STATE_SIGNATURE)
+      {
+         if (file->length != sig1 || file->type != sig2)
+            stop(file, LIBPNG_ERROR_CODE, "not a PNG (signature)");
+
+         /* Else write it (this is the initialization of write_count, prior to
+          * this it contains CLEAR garbage.)
+          */
+         file->write_count = 0;
+      }
+
+      else
+      {
+         assert(file->state == STATE_CHUNKS);
+
+         /* The first chunk must be a well formed IHDR (this could be relaxed to
+          * use the checks in process_chunk, but that seems unnecessary.)
+          */
+         if (file->length != 13 || file->type != png_IHDR)
+            stop(file, LIBPNG_ERROR_CODE, "not a PNG (IHDR)");
+
+         /* The position of the data must be stored too */
+         getpos(file);
+      }
+   }
+
+   /* Retrieve previous state (because the read callbacks are made pretty much
+    * byte-by-byte in the sequential reader prior to 1.7).
+    */
+   chunk = file->chunk;
+
+   if (chunk != NULL)
+   {
+      length = chunk->chunk_length;
+      type = chunk->chunk_type;
+   }
+
+   else
+   {
+      /* This is the signature case; for IDAT and other chunks these values will
+       * be overwritten when read_chunk is called below.
+       */
+      length = file->length;
+      type = file->type;
+   }
+
+   do
+   {
+      png_uint_32 b;
+
+      /* Complete the read of a chunk; as a side effect this also instantiates
+       * a chunk control structure and sets the file length/type/data_pos fields
+       * for the *NEXT* chunk header.
+       *
+       * NOTE: at an IDAT any following IDAT chunks will also be read and the
+       * next_ fields will refer to the chunk after the last IDAT.
+       *
+       * NOTE: read_chunk only returns when it has read a chunk that must now be
+       * written.
+       */
+      if (file->state != STATE_SIGNATURE && chunk == NULL)
+      {
+         assert(file->read_count == 8);
+         assert(file->idat == NULL);
+         read_chunk(file);
+         chunk = file->chunk;
+         assert(chunk != NULL);
+
+         /* Do the initialization that was not done before. */
+         length = chunk->chunk_length;
+         type = chunk->chunk_type;
+
+         /* And start writing the new chunk. */
+         file->write_count = 0;
+      }
+
+      /* The chunk_ fields describe a chunk that must be written, or hold the
+       * signature.  Write the header first.  In the signature case this
+       * rewrites the signature.
+       */
+      switch (file->write_count)
+      {
+         case 0: b = length >> 24; break;
+         case 1: b = length >> 16; break;
+         case 2: b = length >>  8; break;
+         case 3: b = length      ; break;
+
+         case 4: b = type >> 24; break;
+         case 5: b = type >> 16; break;
+         case 6: b = type >>  8; break;
+         case 7: b = type      ; break;
+
+         case 8:
+            /* The header has been written.  If this is really the signature
+             * that's all that is required and we can go to normal chunk
+             * processing.
+             */
+            if (file->state == STATE_SIGNATURE)
+            {
+               /* The signature has been written, the tail call to read_callback
+                * below (it's just a goto to the start with a decent compiler)
+                * will read the IHDR header ahead and validate it.
+                */
+               assert(length == sig1 && type == sig2);
+               file->read_count = 0; /* Forces a header read */
+               file->state = STATE_CHUNKS; /* IHDR: checked above */
+               read_callback(png_ptr, buffer, count);
+               return;
+            }
+
+            else
+            {
+               assert(chunk != NULL);
+
+               /* Set up for write, notice that repositioning the input stream
+                * is only necessary if something is to be read from it.  Also
+                * notice that for the IDAT stream this must only happen once -
+                * on the first IDAT - to get back to the start of the list and
+                * this is done inside process_IDAT:
+                */
+               chunk->write_crc = crc_init_4(type);
+               if (file->state != STATE_IDAT && length > 0)
+                  setpos(chunk);
+            }
+            /* FALLTHROUGH */
+
+         default:
+            assert(chunk != NULL);
+
+            /* NOTE: the arithmetic below overflows and gives a large positive
+             * png_uint_32 value until the whole chunk data has been written.
+             */
+            switch (file->write_count - length)
+            {
+               /* Write the chunk data, normally this just comes from
+                * the file.  The only exception is for that part of a
+                * chunk which is zlib data and which must be rewritten,
+                * and IDAT chunks which can be completely
+                * reconstructed.
+                */
+               default:
+                  if (file->state == STATE_IDAT)
+                  {
+                     struct IDAT *idat = file->idat;
+
+                     assert(idat != NULL);
+
+                     /* Read an IDAT byte from the input stream of IDAT chunks.
+                      * Because the IDAT stream can be re-chunked this stream is
+                      * held in the struct IDAT members.  The chunk members, in
+                      * particular chunk_length (and therefore the length local)
+                      * refer to the output chunk.
+                      */
+                     while (idat->idat_index >= idat->idat_length)
+                     {
+                        /* Advance one chunk */
+                        struct IDAT_list *cur = idat->idat_cur;
+
+                        assert(idat->idat_index == idat->idat_length);
+                        assert(cur != NULL && cur->count > 0);
+
+                        /* NOTE: IDAT_list::count here, not IDAT_list::length */
+                        if (++(idat->idat_count) >= cur->count)
+                        {
+                           assert(idat->idat_count == cur->count);
+
+                           /* Move on to the next IDAT_list: */
+                           cur = cur->next;
+
+                           /* This is an internal error - read beyond the end of
+                            * the pre-calculated stream.
+                            */
+                           if (cur == NULL || cur->count == 0)
+                              stop(file, UNEXPECTED_ERROR_CODE,
+                                 "read beyond end of IDAT");
+
+                           idat->idat_count = 0;
+                           idat->idat_cur = cur;
+                        }
+
+                        idat->idat_index = 0;
+                        /* Zero length IDAT chunks are permitted, so the length
+                         * here may be 0.
+                         */
+                        idat->idat_length = cur->lengths[idat->idat_count];
+
+                        /* And skip 12 bytes to the next chunk data */
+                        skip_12(file);
+                     }
+
+                     /* The index is always that of the next byte, the rest of
+                      * the information is always the current IDAT chunk and the
+                      * current list.
+                      */
+                     ++(idat->idat_index);
+                  }
+
+                  /* Read the byte from the stream. */
+                  b = reread_byte(file);
+
+                  /* If the byte must be rewritten handle that here */
+                  if (chunk->rewrite_length > 0)
+                  {
+                     if (chunk->rewrite_offset > 0)
+                        --(chunk->rewrite_offset);
+
+                     else
+                     {
+                        b = chunk->rewrite_buffer[0];
+                        memmove(chunk->rewrite_buffer, chunk->rewrite_buffer+1,
+                           (sizeof chunk->rewrite_buffer)-
+                              (sizeof chunk->rewrite_buffer[0]));
+
+                        --(chunk->rewrite_length);
+                     }
+                  }
+
+                  chunk->write_crc = crc_one_byte(chunk->write_crc, b);
+                  break;
+
+               /* The CRC is written at:
+                *
+                *    chunk_write == chunk_length+8..chunk_length+11
+                *
+                * so 8 to 11.  The CRC is not (yet) conditioned.
+                */
+               case  8: b = chunk->write_crc >> 24; goto write_crc;
+               case  9: b = chunk->write_crc >> 16; goto write_crc;
+               case 10: b = chunk->write_crc >>  8; goto write_crc;
+               case 11:
+                  /* This must happen before the chunk_end below: */
+                  b = chunk->write_crc;
+
+                  if (file->global->verbose > 2)
+                  {
+                     fputs("   ", stderr);
+                     type_name(type, stderr);
+                     fprintf(stderr, " %lu 0x%.8x\n", (unsigned long)length,
+                        chunk->write_crc ^ 0xffffffff);
+                  }
+
+                  /* The IDAT stream is written without a call to read_chunk
+                   * until the end is reached.  rechunk_length() calculates the
+                   * length of the output chunks.  Control gets to this point at
+                   * the end of an *output* chunk - the length calculated by
+                   * rechunk_length.  If this corresponds to the end of the
+                   * input stream stop writing IDAT chunks, otherwise continue.
+                   */
+                  if (file->state == STATE_IDAT &&
+                     (file->idat->idat_index < file->idat->idat_length ||
+                      1+file->idat->idat_count < file->idat->idat_cur->count ||
+                      file->idat->idat_cur != file->idat->idat_list_tail))
+                  {
+                     /* Write another IDAT chunk.  Call rechunk_length to
+                      * calculate the length required.
+                      */
+                     length = chunk->chunk_length =
+                         rechunk_length(file->idat, 0/*end*/);
+                     assert(type == png_IDAT);
+                     file->write_count = 0; /* for the new chunk */
+                     --(file->write_count); /* fake out the increment below */
+                  }
+
+                  else
+                  {
+                     /* Entered at the end of a non-IDAT chunk and at the end of
+                      * the IDAT stream.  The rewrite should have been cleared.
+                      */
+                     if (chunk->rewrite_length > 0 || chunk->rewrite_offset > 0)
+                        stop(file, UNEXPECTED_ERROR_CODE, "pending rewrite");
+
+                     /* This is the last byte so reset chunk_read for the next
+                      * chunk and move the input file to the position after the
+                      * *next* chunk header if required.
+                      */
+                     file->read_count = 8;
+                     file_setpos(file, &file->data_pos);
+
+                     if (file->idat == NULL)
+                        chunk_end(&file->chunk);
+
+                     else
+                        IDAT_end(&file->idat);
+                  }
+
+               write_crc:
+                  b ^= 0xff; /* conditioning */
+                  break;
+            }
+            break;
+      }
+
+      /* Write one byte */
+      b &= 0xff;
+      *buffer++ = (png_byte)b;
+      --count;
+      write_byte(file, (png_byte)b); /* increments chunk_write */
+   }
+   while (count > 0);
+}
+
+/* Bundle the file and an uninitialized chunk and IDAT control structure
+ * together to allow implementation of the chunk/IDAT allocate routine.
+ */
+struct control
+{
+   struct file  file;
+   struct chunk chunk;
+   struct IDAT  idat;
+};
+
+static int
+control_end(struct control *control)
+{
+   return file_end(&control->file);
+}
+
+static struct file *
+get_control(png_const_structrp png_ptr)
+{
+   /* This just returns the (file*).  The chunk and idat control structures
+    * don't always exist.
+    */
+   struct control *control = voidcast(struct control*,
+      png_get_error_ptr(png_ptr));
+   return &control->file;
+}
+
+static void
+allocate(struct file *file, int allocate_idat)
+{
+   struct control *control = voidcast(struct control*, file->alloc_ptr);
+
+   if (allocate_idat)
+   {
+      assert(file->idat == NULL);
+      IDAT_init(&control->idat, file);
+   }
+
+   else /* chunk */
+   {
+      assert(file->chunk == NULL);
+      chunk_init(&control->chunk, file);
+   }
+}
+
+static int
+control_init(struct control *control, struct global *global,
+   const char *file_name, const char *out_name)
+   /* This wraps file_init(&control::file) and simply returns the result from
+    * file_init.
+    */
+{
+   return file_init(&control->file, global, file_name, out_name, control,
+      allocate);
+}
+
+static int
+read_png(struct control *control)
+   /* Read a PNG, return 0 on success else an error (status) code; a bit mask as
+    * defined for file::status_code as above.
+    */
+{
+   png_structp png_ptr;
+   png_infop info_ptr = NULL;
+   volatile int rc;
+
+   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, control,
+      error_handler, warning_handler);
+
+   if (png_ptr == NULL)
+   {
+      /* This is not really expected. */
+      log_error(&control->file, LIBPNG_ERROR_CODE, "OOM allocating png_struct");
+      control->file.status_code |= INTERNAL_ERROR;
+      return LIBPNG_ERROR_CODE;
+   }
+
+   rc = setjmp(control->file.jmpbuf);
+   if (rc == 0)
+   {
+#     ifdef PNG_SET_USER_LIMITS_SUPPORTED
+         /* Remove any limits on the size of PNG files that can be read,
+          * without this we may reject files based on built-in safety
+          * limits.
+          */
+         png_set_user_limits(png_ptr, 0x7fffffff, 0x7fffffff);
+         png_set_chunk_cache_max(png_ptr, 0);
+         png_set_chunk_malloc_max(png_ptr, 0);
+#     endif
+
+      png_set_read_fn(png_ptr, control, read_callback);
+
+      info_ptr = png_create_info_struct(png_ptr);
+      if (info_ptr == NULL)
+         png_error(png_ptr, "OOM allocating info structure");
+
+      if (control->file.global->verbose)
+         fprintf(stderr, " INFO\n");
+
+      png_read_info(png_ptr, info_ptr);
+
+      {
+        png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
+        int passes = png_set_interlace_handling(png_ptr);
+        int pass;
+
+        png_start_read_image(png_ptr);
+
+        for (pass = 0; pass < passes; ++pass)
+        {
+           png_uint_32 y = height;
+
+           /* NOTE: this skips asking libpng to return either version of
+            * the image row, but libpng still reads the rows.
+            */
+           while (y-- > 0)
+              png_read_row(png_ptr, NULL, NULL);
+        }
+      }
+
+      if (control->file.global->verbose)
+         fprintf(stderr, " END\n");
+
+      /* Make sure to read to the end of the file: */
+      png_read_end(png_ptr, info_ptr);
+   }
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   return rc;
+}
+
+static int
+one_file(struct global *global, const char *file_name, const char *out_name)
+{
+   int rc;
+   struct control control;
+
+   if (global->verbose)
+      fprintf(stderr, "FILE %s -> %s\n", file_name,
+         out_name ? out_name : "<none>");
+
+   /* Although control_init can return a failure code the structure is always
+    * initialized, so control_end can be used to accumulate any status codes.
+    */
+   rc = control_init(&control, global, file_name, out_name);
+
+   if (rc == 0)
+      rc = read_png(&control);
+
+   rc |= control_end(&control);
+
+   return rc;
+}
+
+static void
+usage(const char *prog)
+{
+   /* ANSI C-90 limits strings to 509 characters, so use a string array: */
+   size_t i;
+   static const char *usage_string[] = {
+"  Tests, optimizes and optionally fixes the zlib header in PNG files.",
+"  Optionally, when fixing, strips ancillary chunks from the file.",
+0,
+"OPTIONS",
+"  OPERATION",
+"      By default files are just checked for readability with a summary of the",
+"      of zlib issues founds for each compressed chunk and the IDAT stream in",
+"      the file.",
+"    --optimize (-o):",
+"      Find the smallest deflate window size for the compressed data.",
+"    --strip=[none|crc|unsafe|unused|transform|color|all]:",
+"        none (default):   Retain all chunks.",
+"        crc:    Remove chunks with a bad CRC.",
+"        unsafe: Remove chunks that may be unsafe to retain if the image data",
+"                is modified.  This is set automatically if --max is given but",
+"                may be cancelled by a later --strip=none.",
+"        unused: Remove chunks not used by libpng when decoding an image.",
+"                This retains any chunks that might be used by libpng image",
+"                transformations.",
+"        transform: unused+bKGD.",
+"        color:  transform+iCCP and cHRM.",
+"        all:    color+gAMA and sRGB.",
+"      Only ancillary chunks are ever removed.  In addition the tRNS and sBIT",
+"      chunks are never removed as they affect exact interpretation of the",
+"      image pixel values.  The following known chunks are treated specially",
+"      by the above options:",
+"        gAMA, sRGB [all]: These specify the gamma encoding used for the pixel",
+"            values.",
+"        cHRM, iCCP [color]: These specify how colors are encoded.  iCCP also",
+"            specifies the exact encoding of a pixel value; however, in",
+"            practice most programs will ignore it.",
+"        bKGD [transform]: This is used by libpng transforms."
+"    --max=<number>:",
+"      Use IDAT chunks sized <number>.  If no number is given the IDAT",
+"      chunks will be the maximum size permitted; 2^31-1 bytes.  If the option",
+"      is omitted the original chunk sizes will not be changed.  When the",
+"      option is given --strip=unsafe is set automatically. This may be",
+"      cancelled if you know that all unknown unsafe-to-copy chunks really are",
+"      safe to copy across an IDAT size change.  This is true of all chunks",
+"      that have ever been formally proposed as PNG extensions.",
+"  MESSAGES",
+"      By default the program only outputs summaries for each file.",
+"    --quiet (-q):",
+"      Do not output the summaries except for files that cannot be read. With",
+"      two --quiets these are not output either.",
+"    --errors (-e):",
+"      Output errors from libpng and the program (except too-far-back).",
+"    --warnings (-w):",
+"      Output warnings from libpng.",
+"  OUTPUT",
+"      By default nothing is written.",
+"    --out=<file>:",
+"      Write the optimized/corrected version of the next PNG to <file>.  This",
+"      overrides the following two options",
+"    --suffix=<suffix>:",
+"      Set --out=<name><suffix> for all following files unless overridden on",
+"      a per-file basis by explicit --out.",
+"    --prefix=<prefix>:",
+"      Set --out=<prefix><name> for all the following files unless overridden",
+"      on a per-file basis by explicit --out.",
+"      These two options can be used together to produce a suffix and prefix.",
+"  INTERNAL OPTIONS",
+#if 0 /*NYI*/
+#ifdef PNG_MAXIMUM_INFLATE_WINDOW
+"    --test:",
+"      Test the PNG_MAXIMUM_INFLATE_WINDOW option.  Setting this disables",
+"      output as this would produce a broken file.",
+#endif
+#endif
+0,
+"EXIT CODES",
+"  *** SUBJECT TO CHANGE ***",
+"  The program exit code is value in the range 0..127 holding a bit mask of",
+"  the following codes.  Notice that the results for each file are combined",
+"  together - check one file at a time to get a meaningful error code!",
+"    0x01: The zlib too-far-back error existed in at least one chunk.",
+"    0x02: At least one chunk had a CRC error.",
+"    0x04: A chunk length was incorrect.",
+"    0x08: The file was truncated.",
+"  Errors less than 16 are potentially recoverable, for a single file if the",
+"  exit code is less than 16 the file could be read (with corrections if a",
+"  non-zero code is returned).",
+"    0x10: The file could not be read, even with corrections.",
+"    0x20: The output file could not be written.",
+"    0x40: An unexpected, potentially internal, error occurred.",
+"  If the command line arguments are incorrect the program exits with exit",
+"  255.  Some older operating systems only support 7-bit exit codes, on those",
+"  systems it is suggested that this program is first tested by supplying",
+"  invalid arguments.",
+0,
+"DESCRIPTION",
+"  " PROGRAM_NAME ":",
+"  checks each PNG file on the command line for errors.  By default errors are",
+"  not output and the program just returns an exit code and prints a summary.",
+"  With the --quiet (-q) option the summaries are suppressed too and the",
+"  program only outputs unexpected errors (internal errors and file open",
+"  errors).",
+"  Various known problems in PNG files are fixed while the file is being read",
+"  The exit code says what problems were fixed.  In particular the zlib error:",
+0,
+"        \"invalid distance too far back\"",
+0,
+"  caused by an incorrect optimization of a zlib stream is fixed in any",
+"  compressed chunk in which it is encountered.  An integrity problem of the",
+"  PNG stream caused by a bug in libpng which wrote an incorrect chunk length",
+"  is also fixed.  Chunk CRC errors are automatically fixed up.",
+0,
+"  Setting one of the \"OUTPUT\" options causes the possibly modified file to",
+"  be written to a new file.",
+0,
+"  Notice that some PNG files with the zlib optimization problem can still be",
+"  read by libpng under some circumstances.  This program will still detect",
+"  and, if requested, correct the error.",
+0,
+"  The program will reliably process all files on the command line unless",
+"  either an invalid argument causes the usage message (this message) to be",
+"  produced or the program crashes.",
+0,
+"  The summary lines describe issues encountered with the zlib compressed",
+"  stream of a chunk.  They have the following format, which is SUBJECT TO",
+"  CHANGE in the future:",
+0,
+"     chunk reason comp-level p1 p2 p3 p4 file",
+0,
+"  p1 through p4 vary according to the 'reason'.  There are always 8 space",
+"  separated fields.  Reasons specific formats are:",
+0,
+"     chunk ERR status code read-errno write-errno message file",
+"     chunk SKP comp-level file-bits zlib-rc compressed message file",
+"     chunk ??? comp-level file-bits ok-bits compressed uncompress file",
+0,
+"  The various fields are",
+0,
+"$1 chunk:      The chunk type of a chunk in the file or 'HEAD' if a problem",
+"               is reported by libpng at the start of the IDAT stream.",
+"$2 reason:     One of:",
+"          CHK: A zlib header checksum was detected and fixed.",
+"          TFB: The zlib too far back error was detected and fixed.",
+"          OK : No errors were detected in the zlib stream and optimization",
+"               was not requested, or was not possible.",
+"          OPT: The zlib stream window bits value could be improved (and was).",
+"          SKP: The chunk was skipped because of a zlib issue (zlib-rc) with",
+"               explanation 'message'",
+"          ERR: The read of the file was aborted.  The parameters explain why.",
+"$3 status:     For 'ERR' the accumulated status code from 'EXIT CODES' above.",
+"               This is printed as a 2 digit hexadecimal value",
+"   comp-level: The recorded compression level (FLEVEL) of a zlib stream",
+"               expressed as a string {supfast,stdfast,default,maximum}",
+"$4 code:       The file exit code; where stop was called, as a fairly terse",
+"               string {warning,libpng,zlib,invalid,read,write,unexpected}.",
+"   file-bits:  The zlib window bits recorded in the file.",
+"$5 read-errno: A system errno value from a read translated by strerror(3).",
+"   zlib-rc:    A zlib return code as a string (see zlib.h).",
+"   ok-bits:    The smallest zlib window bits value that works.",
+"$6 write-errno:A system errno value from a write translated by strerror(3).",
+"   compressed: The count of compressed bytes in the zlib stream, when the",
+"               reason is 'SKP'; this is a count of the bytes read from the",
+"               stream when the fatal error was encountered.",
+"$7 message:    An error message (spaces replaced by _, as in all parameters),",
+"   uncompress: The count of bytes from uncompressing the zlib stream; this",
+"               may not be the same as the number of bytes in the image.",
+"$8 file:       The name of the file (this may contain spaces).",
+};
+
+   fprintf(stderr, "Usage: %s {[options] png-file}\n", prog);
+
+   for (i=0; i < (sizeof usage_string)/(sizeof usage_string[0]); ++i)
+   {
+      if (usage_string[i] != 0)
+         fputs(usage_string[i], stderr);
+
+      fputc('\n', stderr);
+   }
+
+   exit(255);
+}
+
+int
+main(int argc, const char **argv)
+{
+   char temp_name[FILENAME_MAX+1];
+   const char *  prog = *argv;
+   const char *  outfile = NULL;
+   const char *  suffix = NULL;
+   const char *  prefix = NULL;
+   int           done = 0; /* if at least one file is processed */
+   struct global global;
+
+   global_init(&global);
+
+   while (--argc > 0)
+   {
+      ++argv;
+
+      if (strcmp(*argv, "--debug") == 0)
+      {
+         /* To help debugging problems: */
+         global.errors = global.warnings = 1;
+         global.quiet = 0;
+         global.verbose = 7;
+      }
+
+      else if (strncmp(*argv, "--max=", 6) == 0)
+      {
+         global.idat_max = (png_uint_32)atol(6+*argv);
+
+         if (global.skip < SKIP_UNSAFE)
+            global.skip = SKIP_UNSAFE;
+      }
+
+      else if (strcmp(*argv, "--max") == 0)
+      {
+         global.idat_max = 0x7fffffff;
+
+         if (global.skip < SKIP_UNSAFE)
+            global.skip = SKIP_UNSAFE;
+      }
+
+      else if (strcmp(*argv, "--optimize") == 0 || strcmp(*argv, "-o") == 0)
+         global.optimize_zlib = 1;
+
+      else if (strncmp(*argv, "--out=", 6) == 0)
+         outfile = 6+*argv;
+
+      else if (strncmp(*argv, "--suffix=", 9) == 0)
+         suffix = 9+*argv;
+
+      else if (strncmp(*argv, "--prefix=", 9) == 0)
+         prefix = 9+*argv;
+
+      else if (strcmp(*argv, "--strip=none") == 0)
+         global.skip = SKIP_NONE;
+
+      else if (strcmp(*argv, "--strip=crc") == 0)
+         global.skip = SKIP_BAD_CRC;
+
+      else if (strcmp(*argv, "--strip=unsafe") == 0)
+         global.skip = SKIP_UNSAFE;
+
+      else if (strcmp(*argv, "--strip=unused") == 0)
+         global.skip = SKIP_UNUSED;
+
+      else if (strcmp(*argv, "--strip=transform") == 0)
+         global.skip = SKIP_TRANSFORM;
+
+      else if (strcmp(*argv, "--strip=color") == 0)
+         global.skip = SKIP_COLOR;
+
+      else if (strcmp(*argv, "--strip=all") == 0)
+         global.skip = SKIP_ALL;
+
+      else if (strcmp(*argv, "--errors") == 0 || strcmp(*argv, "-e") == 0)
+         global.errors = 1;
+
+      else if (strcmp(*argv, "--warnings") == 0 || strcmp(*argv, "-w") == 0)
+         global.warnings = 1;
+
+      else if (strcmp(*argv, "--quiet") == 0 || strcmp(*argv, "-q") == 0)
+      {
+         if (global.quiet)
+            global.quiet = 2;
+
+         else
+            global.quiet = 1;
+      }
+
+      else if (strcmp(*argv, "--verbose") == 0 || strcmp(*argv, "-v") == 0)
+         ++global.verbose;
+
+#if 0
+      /* NYI */
+#     ifdef PNG_MAXIMUM_INFLATE_WINDOW
+         else if (strcmp(*argv, "--test") == 0)
+            ++set_option;
+#     endif
+#endif
+
+      else if ((*argv)[0] == '-')
+         usage(prog);
+
+      else
+      {
+         size_t outlen = strlen(*argv);
+
+         if (outfile == NULL) /* else this takes precedence */
+         {
+            /* Consider the prefix/suffix options */
+            if (prefix != NULL)
+            {
+               size_t prefixlen = strlen(prefix);
+
+               if (prefixlen+outlen > FILENAME_MAX)
+               {
+                  fprintf(stderr, "%s: output file name too long: %s%s%s\n",
+                     prog, prefix, *argv, suffix ? suffix : "");
+                  global.status_code |= WRITE_ERROR;
+                  continue;
+               }
+
+               memcpy(temp_name, prefix, prefixlen);
+               memcpy(temp_name+prefixlen, *argv, outlen);
+               outlen += prefixlen;
+               outfile = temp_name;
+            }
+
+            else if (suffix != NULL)
+               memcpy(temp_name, *argv, outlen);
+
+            temp_name[outlen] = 0;
+
+            if (suffix != NULL)
+            {
+               size_t suffixlen = strlen(suffix);
+
+               if (outlen+suffixlen > FILENAME_MAX)
+               {
+                  fprintf(stderr, "%s: output file name too long: %s%s\n",
+                     prog, *argv, suffix);
+                  global.status_code |= WRITE_ERROR;
+                  continue;
+               }
+
+               memcpy(temp_name+outlen, suffix, suffixlen);
+               outlen += suffixlen;
+               temp_name[outlen] = 0;
+               outfile = temp_name;
+            }
+         }
+
+         (void)one_file(&global, *argv, outfile);
+         ++done;
+         outfile = NULL;
+      }
+   }
+
+   if (!done)
+      usage(prog);
+
+   return global_end(&global);
+}
+
+#else /* ZLIB_VERNUM < 0x1240 */
+int
+main(void)
+{
+   fprintf(stderr,
+      "pngfix needs libpng with a zlib >=1.2.4 (not 0x%x)\n",
+      ZLIB_VERNUM);
+   return 77;
+}
+#endif /* ZLIB_VERNUM */
+
+#else /* No read support */
+
+int
+main(void)
+{
+   fprintf(stderr, "pngfix does not work without read deinterlace support\n");
+   return 77;
+}
+#endif /* PNG_READ_SUPPORTED && PNG_EASY_ACCESS_SUPPORTED */
+#else /* No setjmp support */
+int
+main(void)
+{
+   fprintf(stderr, "pngfix does not work without setjmp support\n");
+   return 77;
+}
+#endif /* PNG_SETJMP_SUPPORTED */
+
diff --git a/extern/libpng/contrib/tools/reindent b/extern/libpng/contrib/tools/reindent
new file mode 100755
index 0000000000..f4df309b66
--- /dev/null
+++ b/extern/libpng/contrib/tools/reindent
@@ -0,0 +1,25 @@
+#!/bin/sh
+
+# reindent a libpng C source
+
+# COPYRIGHT: Written by Glenn Randers-Pehrson, 2016.
+# To the extent possible under law, the author has waived all copyright and
+# related or neighboring rights to this work.  This work is published from:
+# United States.
+
+# Usage:
+# reindent inputtabsize outputtabsize inputcontinuestring outputcontinuestring
+#
+# Assumes that continued lines begin with indentation plus one space, and
+# that continued comments begin with indentation plus " *".
+#
+# eg, to change libpng coding style from 3-space indentation with 4-space
+# continuations to 4-space indentation with 2-space continuations:
+#
+#  reindent 3 4 "\t " "  " < example.c > example.c_4_2
+# and to restore the file back to libpng coding style
+#  reindent 4 3 "  " "    " < example.c_4_2 > example.c_3_4
+
+unexpand --first-only --t $1 | \
+   sed -e "/^	*$3[^\*]/{s/$3/$4/}" | \
+   expand -t $2
diff --git a/extern/libpng/contrib/tools/sRGB.h b/extern/libpng/contrib/tools/sRGB.h
new file mode 100644
index 0000000000..d1ece51291
--- /dev/null
+++ b/extern/libpng/contrib/tools/sRGB.h
@@ -0,0 +1,48 @@
+/*-
+ * sRGB.h
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2013.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Utility file; not actually a header, this contains definitions of sRGB
+ * calculation functions for inclusion in those test programs that need them.
+ *
+ * All routines take and return a floating point value in the range
+ * 0 to 1.0, doing a calculation according to the sRGB specification
+ * (in fact the source of the numbers is the wikipedia article at
+ * https://en.wikipedia.org/wiki/SRGB).
+ */
+static double
+sRGB_from_linear(double l)
+{
+   if (l <= 0.0031308)
+      l *= 12.92;
+
+   else
+      l = 1.055 * pow(l, 1/2.4) - 0.055;
+
+   return l;
+}
+
+static double
+linear_from_sRGB(double s)
+{
+   if (s <= 0.04045)
+      return s / 12.92;
+
+   else
+      return pow((s+0.055)/1.055, 2.4);
+}
+
+static double
+YfromRGB(double r, double g, double b)
+{
+   /* Use the sRGB (rounded) coefficients for Rlinear, Glinear, Blinear to get
+    * the CIE Y value (also linear).
+    */
+   return 0.2126 * r + 0.7152 * g + 0.0722 * b;
+}
diff --git a/extern/libpng/contrib/visupng/PngFile.c b/extern/libpng/contrib/visupng/PngFile.c
new file mode 100644
index 0000000000..cf943f32a6
--- /dev/null
+++ b/extern/libpng/contrib/visupng/PngFile.c
@@ -0,0 +1,454 @@
+/*-------------------------------------
+ *  PNGFILE.C -- Image File Functions
+ *-------------------------------------
+ *
+ * Copyright 2000,2017 Willem van Schaik.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include <windows.h>
+#include <commdlg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <zlib.h>
+
+#include "png.h"
+#include "pngfile.h"
+#include "cexcept.h"
+
+define_exception_type(const char *);
+extern struct exception_context the_exception_context[1];
+struct exception_context the_exception_context[1];
+png_const_charp msg;
+
+static OPENFILENAME ofn;
+
+static png_structp png_ptr = NULL;
+static png_infop info_ptr = NULL;
+
+
+/* cexcept interface */
+
+static void
+png_cexcept_error(png_structp png_ptr, png_const_charp msg)
+{
+   if(png_ptr)
+     ;
+#ifdef PNG_CONSOLE_IO_SUPPORTED
+   fprintf(stderr, "libpng error: %s\n", msg);
+#endif
+   {
+      Throw msg;
+   }
+}
+
+/* Windows open-file functions */
+
+void PngFileInitialize (HWND hwnd)
+{
+    static TCHAR szFilter[] = TEXT ("PNG Files (*.PNG)\0*.png\0")
+        TEXT ("All Files (*.*)\0*.*\0\0");
+
+    ofn.lStructSize       = sizeof (OPENFILENAME);
+    ofn.hwndOwner         = hwnd;
+    ofn.hInstance         = NULL;
+    ofn.lpstrFilter       = szFilter;
+    ofn.lpstrCustomFilter = NULL;
+    ofn.nMaxCustFilter    = 0;
+    ofn.nFilterIndex      = 0;
+    ofn.lpstrFile         = NULL;          /* Set in Open and Close functions */
+    ofn.nMaxFile          = MAX_PATH;
+    ofn.lpstrFileTitle    = NULL;          /* Set in Open and Close functions */
+    ofn.nMaxFileTitle     = MAX_PATH;
+    ofn.lpstrInitialDir   = NULL;
+    ofn.lpstrTitle        = NULL;
+    ofn.Flags             = 0;             /* Set in Open and Close functions */
+    ofn.nFileOffset       = 0;
+    ofn.nFileExtension    = 0;
+    ofn.lpstrDefExt       = TEXT ("png");
+    ofn.lCustData         = 0;
+    ofn.lpfnHook          = NULL;
+    ofn.lpTemplateName    = NULL;
+}
+
+BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName)
+{
+    ofn.hwndOwner         = hwnd;
+    ofn.lpstrFile         = pstrFileName;
+    ofn.lpstrFileTitle    = pstrTitleName;
+    ofn.Flags             = OFN_HIDEREADONLY;
+
+    return GetOpenFileName (&ofn);
+}
+
+BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName)
+{
+    ofn.hwndOwner         = hwnd;
+    ofn.lpstrFile         = pstrFileName;
+    ofn.lpstrFileTitle    = pstrTitleName;
+    ofn.Flags             = OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT;
+
+    return GetSaveFileName (&ofn);
+}
+
+/* PNG image handler functions */
+
+BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
+                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor)
+{
+    static FILE        *pfFile;
+    png_byte            pbSig[8];
+    int                 iBitDepth;
+    int                 iColorType;
+    double              dGamma;
+    png_color_16       *pBackground;
+    png_uint_32         ulChannels;
+    png_uint_32         ulRowBytes;
+    png_byte           *pbImageData = *ppbImageData;
+    static png_byte   **ppbRowPointers = NULL;
+    int                 i;
+
+    /* open the PNG input file */
+
+    if (!pstrFileName)
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    if (!(pfFile = fopen(pstrFileName, "rb")))
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    /* first check the eight byte PNG signature */
+
+    fread(pbSig, 1, 8, pfFile);
+    if (png_sig_cmp(pbSig, 0, 8))
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    /* create the two png(-info) structures */
+
+    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
+      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
+    if (!png_ptr)
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr)
+    {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    Try
+    {
+
+        /* initialize the png structure */
+
+#ifdef PNG_STDIO_SUPPORTED
+        png_init_io(png_ptr, pfFile);
+#else
+        png_set_read_fn(png_ptr, (png_voidp)pfFile, png_read_data);
+#endif
+
+        png_set_sig_bytes(png_ptr, 8);
+
+        /* read all PNG info up to image data */
+
+        png_read_info(png_ptr, info_ptr);
+
+        /* get width, height, bit-depth and color-type */
+
+        png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
+            &iColorType, NULL, NULL, NULL);
+
+        /* expand images of all color-type and bit-depth to 3x8-bit RGB */
+        /* let the library process alpha, transparency, background, etc. */
+
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+    if (iBitDepth == 16)
+#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+        png_set_scale_16(png_ptr);
+#  else
+        png_set_strip_16(png_ptr);
+#  endif
+#endif
+        if (iColorType == PNG_COLOR_TYPE_PALETTE)
+            png_set_expand(png_ptr);
+        if (iBitDepth < 8)
+            png_set_expand(png_ptr);
+        if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+            png_set_expand(png_ptr);
+        if (iColorType == PNG_COLOR_TYPE_GRAY ||
+            iColorType == PNG_COLOR_TYPE_GRAY_ALPHA)
+            png_set_gray_to_rgb(png_ptr);
+
+        /* set the background color to draw transparent and alpha images over */
+        if (png_get_bKGD(png_ptr, info_ptr, &pBackground))
+        {
+            png_set_background(png_ptr, pBackground, PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+            pBkgColor->red   = (byte) pBackground->red;
+            pBkgColor->green = (byte) pBackground->green;
+            pBkgColor->blue  = (byte) pBackground->blue;
+        }
+        else
+        {
+            pBkgColor = NULL;
+        }
+
+        /* if required set gamma conversion */
+        if (png_get_gAMA(png_ptr, info_ptr, &dGamma))
+            png_set_gamma(png_ptr, (double) 2.2, dGamma);
+
+        /* after the transformations are registered, update info_ptr data */
+
+        png_read_update_info(png_ptr, info_ptr);
+
+        /* get again width, height and the new bit-depth and color-type */
+
+        png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
+            &iColorType, NULL, NULL, NULL);
+
+
+        /* row_bytes is the width x number of channels */
+
+        ulRowBytes = png_get_rowbytes(png_ptr, info_ptr);
+        ulChannels = png_get_channels(png_ptr, info_ptr);
+
+        *piChannels = ulChannels;
+
+        /* now we can allocate memory to store the image */
+
+        if (pbImageData)
+        {
+            free (pbImageData);
+            pbImageData = NULL;
+        }
+        if ((*piHeight) > ((size_t)(-1))/ulRowBytes) {
+        {
+            png_error(png_ptr, "Visual PNG: image is too big");
+        }
+        if ((pbImageData = (png_byte *) malloc(ulRowBytes * (*piHeight)
+                            * sizeof(png_byte))) == NULL)
+        {
+            png_error(png_ptr, "Visual PNG: out of memory");
+        }
+        *ppbImageData = pbImageData;
+
+        /* and allocate memory for an array of row-pointers */
+
+        if ((ppbRowPointers = (png_bytepp) malloc((*piHeight)
+                            * sizeof(png_bytep))) == NULL)
+        {
+            png_error(png_ptr, "Visual PNG: out of memory");
+        }
+
+        /* set the individual row-pointers to point at the correct offsets */
+
+        for (i = 0; i < (*piHeight); i++)
+            ppbRowPointers[i] = pbImageData + i * ulRowBytes;
+
+        /* now we can go ahead and just read the whole image */
+
+        png_read_image(png_ptr, ppbRowPointers);
+
+        /* read the additional chunks in the PNG file (not really needed) */
+
+        png_read_end(png_ptr, NULL);
+
+        /* and we're done */
+
+        free (ppbRowPointers);
+        ppbRowPointers = NULL;
+
+        /* yepp, done */
+    }
+
+    Catch (msg)
+    {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+        *ppbImageData = pbImageData = NULL;
+
+        if(ppbRowPointers)
+            free (ppbRowPointers);
+
+        fclose(pfFile);
+
+        return FALSE;
+    }
+
+    fclose (pfFile);
+
+    return TRUE;
+}
+
+
+BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
+                   int iWidth, int iHeight, png_color bkgColor)
+{
+    const int           ciBitDepth = 8;
+    const int           ciChannels = 3;
+
+    static FILE        *pfFile;
+    png_uint_32         ulRowBytes;
+    static png_byte   **ppbRowPointers = NULL;
+    int                 i;
+
+    /* open the PNG output file */
+
+    if (!pstrFileName)
+        return FALSE;
+
+    if (!(pfFile = fopen(pstrFileName, "wb")))
+        return FALSE;
+
+    /* prepare the standard PNG structures */
+
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
+      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
+    if (!png_ptr)
+    {
+        fclose(pfFile);
+        return FALSE;
+    }
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        fclose(pfFile);
+        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+        return FALSE;
+    }
+
+    Try
+    {
+        /* initialize the png structure */
+
+#ifdef PNG_STDIO_SUPPORTED
+        png_init_io(png_ptr, pfFile);
+#else
+        png_set_write_fn(png_ptr, (png_voidp)pfFile, png_write_data, png_flush);
+#endif
+
+        /* we're going to write a very simple 3x8-bit RGB image */
+
+        png_set_IHDR(png_ptr, info_ptr, iWidth, iHeight, ciBitDepth,
+            PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
+            PNG_FILTER_TYPE_BASE);
+
+        /* write the file header information */
+
+        png_write_info(png_ptr, info_ptr);
+
+        /* swap the BGR pixels in the DiData structure to RGB */
+
+        png_set_bgr(png_ptr);
+
+        /* row_bytes is the width x number of channels */
+
+        ulRowBytes = iWidth * ciChannels;
+
+        /* we can allocate memory for an array of row-pointers */
+
+        if ((ppbRowPointers = (png_bytepp) malloc(iHeight * sizeof(png_bytep))) == NULL)
+            Throw "Visualpng: Out of memory";
+
+        /* set the individual row-pointers to point at the correct offsets */
+
+        for (i = 0; i < iHeight; i++)
+            ppbRowPointers[i] = pDiData + i * (((ulRowBytes + 3) >> 2) << 2);
+
+        /* write out the entire image data in one call */
+
+        png_write_image (png_ptr, ppbRowPointers);
+
+        /* write the additional chunks to the PNG file (not really needed) */
+
+        png_write_end(png_ptr, info_ptr);
+
+        /* and we're done */
+
+        free (ppbRowPointers);
+        ppbRowPointers = NULL;
+
+        /* clean up after the write, and free any memory allocated */
+
+        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+
+        /* yepp, done */
+    }
+
+    Catch (msg)
+    {
+        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+
+        if(ppbRowPointers)
+            free (ppbRowPointers);
+
+        fclose(pfFile);
+
+        return FALSE;
+    }
+
+    fclose (pfFile);
+
+    return TRUE;
+}
+
+#ifndef PNG_STDIO_SUPPORTED
+
+static void
+png_read_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check;
+
+   /* fread() returns 0 on error, so it is OK to store this in a size_t
+    * instead of an int, which is what fread() actually returns.
+    */
+   check = fread(data, 1, length, (FILE *)png_ptr->io_ptr);
+
+   if (check != length)
+   {
+      png_error(png_ptr, "Read Error");
+   }
+}
+
+static void
+png_write_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   png_uint_32 check;
+
+   check = fwrite(data, 1, length, (FILE *)(png_ptr->io_ptr));
+   if (check != length)
+   {
+      png_error(png_ptr, "Write Error");
+   }
+}
+
+static void
+png_flush(png_structp png_ptr)
+{
+   FILE *io_ptr;
+   io_ptr = (FILE *)CVT_PTR((png_ptr->io_ptr));
+   if (io_ptr != NULL)
+      fflush(io_ptr);
+}
+
+#endif
+
+/*-----------------
+ *  end of source
+ *-----------------
+ */
diff --git a/extern/libpng/contrib/visupng/PngFile.h b/extern/libpng/contrib/visupng/PngFile.h
new file mode 100644
index 0000000000..1b7b9be3c3
--- /dev/null
+++ b/extern/libpng/contrib/visupng/PngFile.h
@@ -0,0 +1,30 @@
+/*------------------------------------------*/
+/*  PNGFILE.H -- Header File for pngfile.c*/
+/*------------------------------------------*/
+
+/* Copyright 2000, Willem van Schaik.*/
+
+/* This code is released under the libpng license.*/
+/* For conditions of distribution and use, see the disclaimer*/
+/* and license in png.h*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <windows.h>
+
+void PngFileInitialize (HWND hwnd) ;
+BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;
+BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;
+
+BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
+                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor);
+BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
+                   int iWidth, int iHeight, png_color BkgColor);
+
+#ifndef PNG_STDIO_SUPPORTED
+static void png_read_data(png_structp png_ptr, png_bytep data, size_t length);
+static void png_write_data(png_structp png_ptr, png_bytep data, size_t length);
+static void png_flush(png_structp png_ptr);
+#endif
+
diff --git a/extern/libpng/contrib/visupng/README.txt b/extern/libpng/contrib/visupng/README.txt
new file mode 100644
index 0000000000..72c5cba179
--- /dev/null
+++ b/extern/libpng/contrib/visupng/README.txt
@@ -0,0 +1,61 @@
+Microsoft Developer Studio Build File, Format Version 6.00 for VisualPng
+------------------------------------------------------------------------
+
+Copyright 2000, Willem van Schaik.
+
+This code is released under the libpng license.
+For conditions of distribution and use, see the disclaimer
+and license in png.h
+
+As a PNG .dll demo VisualPng is finished. More features would only hinder
+the program's objective. However, further extensions (like support for other
+graphics formats) are in development. To get these, or for pre-compiled
+binaries, go to "http://www.schaik.com/png/visualpng.html".
+
+------------------------------------------------------------------------
+
+Assumes that
+
+   libpng DLLs and LIBs are in ..\..\projects\msvc\win32\libpng
+   zlib DLLs and LIBs are in   ..\..\projects\msvc\win32\zlib
+   libpng header files are in  ..\..\..\libpng
+   zlib header files are in    ..\..\..\zlib
+   the pngsuite images are in  ..\pngsuite
+
+To build:
+
+1) On the main menu Select "Build|Set Active configuration".
+   Choose the configuration that corresponds to the library you want to test.
+   This library must have been built using the libpng MS project located in
+   the "..\..\mscv" subdirectory.
+
+2) Select "Build|Clean"
+
+3) Select "Build|Rebuild All"
+
+4) After compiling and linking VisualPng will be started to view an image
+   from the PngSuite directory.  Press Ctrl-N (and Ctrl-V) for other images.
+
+
+To install:
+
+When distributing VisualPng (or a further development) the following options
+are available:
+
+1) Build the program with the configuration "Win32 LIB" and you only need to
+   include the executable from the ./lib directory in your distribution.
+
+2) Build the program with the configuration "Win32 DLL" and you need to put
+   in your distribution the executable from the ./dll directory and the dll's
+   libpng1.dll, zlib.dll and msvcrt.dll.  These need to be in the user's PATH.
+
+
+Willem van Schaik
+Calgary, June 6th 2000
+
+P.S. VisualPng was written based on preliminary work of:
+
+    - Simon-Pierre Cadieux
+    - Glenn Randers-Pehrson
+    - Greg Roelofs
+
diff --git a/extern/libpng/contrib/visupng/VisualPng.c b/extern/libpng/contrib/visupng/VisualPng.c
new file mode 100644
index 0000000000..6baa3b6630
--- /dev/null
+++ b/extern/libpng/contrib/visupng/VisualPng.c
@@ -0,0 +1,978 @@
+/*------------------------------------
+ *  VisualPng.C -- Shows a PNG image
+ *------------------------------------
+ *
+ * Copyright 2000,2017 Willem van Schaik.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* switches */
+
+/* defines */
+
+#define PROGNAME  "VisualPng"
+#define LONGNAME  "Win32 Viewer for PNG-files"
+#define VERSION   "1.0 of 2000 June 07"
+
+/* constants */
+
+#define MARGIN 8
+
+/* standard includes */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <windows.h>
+#include <zlib.h>
+
+/* application includes */
+
+#include "png.h"
+#include "pngfile.h"
+#include "resource.h"
+
+/* macros */
+
+/* function prototypes */
+
+LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
+BOOL    CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ;
+
+BOOL CenterAbout (HWND hwndChild, HWND hwndParent);
+
+BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
+        int *pFileIndex);
+
+BOOL SearchPngList (TCHAR *pFileList, int FileCount, int *pFileIndex,
+        PTSTR pstrPrevName, PTSTR pstrNextName);
+
+BOOL LoadImageFile(HWND hwnd, PTSTR pstrPathName,
+        png_byte **ppbImage, int *pxImgSize, int *pyImgSize, int *piChannels,
+        png_color *pBkgColor);
+
+BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
+        BYTE **ppDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched);
+
+BOOL InitBitmap (
+        BYTE *pDiData, int cxWinSize, int cyWinSize);
+
+BOOL FillBitmap (
+        BYTE *pDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched);
+
+/* a few global variables */
+
+static char *szProgName = PROGNAME;
+static char *szAppName = LONGNAME;
+static char *szIconName = PROGNAME;
+static char szCmdFileName [MAX_PATH];
+
+/* MAIN routine */
+
+int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
+                    PSTR szCmdLine, int iCmdShow)
+{
+    HACCEL   hAccel;
+    HWND     hwnd;
+    MSG      msg;
+    WNDCLASS wndclass;
+    int ixBorders, iyBorders;
+
+    wndclass.style         = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc   = WndProc;
+    wndclass.cbClsExtra    = 0;
+    wndclass.cbWndExtra    = 0;
+    wndclass.hInstance     = hInstance;
+    wndclass.hIcon         = LoadIcon (hInstance, szIconName) ;
+    wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW);
+    wndclass.hbrBackground = NULL; /* (HBRUSH) GetStockObject (GRAY_BRUSH); */
+    wndclass.lpszMenuName  = szProgName;
+    wndclass.lpszClassName = szProgName;
+
+    if (!RegisterClass (&wndclass))
+    {
+        MessageBox (NULL, TEXT ("Error: this program requires Windows NT!"),
+            szProgName, MB_ICONERROR);
+        return 0;
+    }
+
+    /* if filename given on commandline, store it */
+    if ((szCmdLine != NULL) && (*szCmdLine != '\0'))
+        if (szCmdLine[0] == '"')
+            strncpy (szCmdFileName, szCmdLine + 1, strlen(szCmdLine) - 2);
+        else
+            strcpy (szCmdFileName, szCmdLine);
+    else
+        strcpy (szCmdFileName, "");
+
+    /* calculate size of window-borders */
+    ixBorders = 2 * (GetSystemMetrics (SM_CXBORDER) +
+                     GetSystemMetrics (SM_CXDLGFRAME));
+    iyBorders = 2 * (GetSystemMetrics (SM_CYBORDER) +
+                     GetSystemMetrics (SM_CYDLGFRAME)) +
+                     GetSystemMetrics (SM_CYCAPTION) +
+                     GetSystemMetrics (SM_CYMENUSIZE) +
+                     1; /* WvS: don't ask me why?  */
+
+    hwnd = CreateWindow (szProgName, szAppName,
+        WS_OVERLAPPEDWINDOW,
+        CW_USEDEFAULT, CW_USEDEFAULT,
+        512 + 2 * MARGIN + ixBorders, 384 + 2 * MARGIN + iyBorders,
+/*      CW_USEDEFAULT, CW_USEDEFAULT, */
+        NULL, NULL, hInstance, NULL);
+
+    ShowWindow (hwnd, iCmdShow);
+    UpdateWindow (hwnd);
+
+    hAccel = LoadAccelerators (hInstance, szProgName);
+
+    while (GetMessage (&msg, NULL, 0, 0))
+    {
+        if (!TranslateAccelerator (hwnd, hAccel, &msg))
+        {
+            TranslateMessage (&msg);
+            DispatchMessage (&msg);
+        }
+    }
+    return msg.wParam;
+}
+
+LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,
+        LPARAM lParam)
+{
+    static HINSTANCE          hInstance ;
+    static HDC                hdc;
+    static PAINTSTRUCT        ps;
+    static HMENU              hMenu;
+
+    static BITMAPFILEHEADER  *pbmfh;
+    static BITMAPINFOHEADER  *pbmih;
+    static BYTE              *pbImage;
+    static int                cxWinSize, cyWinSize;
+    static int                cxImgSize, cyImgSize;
+    static int                cImgChannels;
+    static png_color          bkgColor = {127, 127, 127};
+
+    static BOOL               bStretched = TRUE;
+
+    static BYTE              *pDib = NULL;
+    static BYTE              *pDiData = NULL;
+
+    static TCHAR              szImgPathName [MAX_PATH];
+    static TCHAR              szTitleName [MAX_PATH];
+
+    static TCHAR             *pPngFileList = NULL;
+    static int                iPngFileCount;
+    static int                iPngFileIndex;
+
+    BOOL                      bOk;
+
+    switch (message)
+    {
+    case WM_CREATE:
+        hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;
+        PngFileInitialize (hwnd);
+
+        strcpy (szImgPathName, "");
+
+        /* in case we process file given on command-line */
+
+        if (szCmdFileName[0] != '\0')
+        {
+            strcpy (szImgPathName, szCmdFileName);
+
+            /* read the other png-files in the directory for later */
+            /* next/previous commands */
+
+            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
+                          &iPngFileIndex);
+
+            /* load the image from file */
+
+            if (!LoadImageFile (hwnd, szImgPathName,
+                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
+                return 0;
+
+            /* invalidate the client area for later update */
+
+            InvalidateRect (hwnd, NULL, TRUE);
+
+            /* display the PNG into the DIBitmap */
+
+            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+        }
+
+        return 0;
+
+    case WM_SIZE:
+        cxWinSize = LOWORD (lParam);
+        cyWinSize = HIWORD (lParam);
+
+        /* invalidate the client area for later update */
+
+        InvalidateRect (hwnd, NULL, TRUE);
+
+        /* display the PNG into the DIBitmap */
+
+        DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+            pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+
+        return 0;
+
+    case WM_INITMENUPOPUP:
+        hMenu = GetMenu (hwnd);
+
+        if (pbImage)
+            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_ENABLED);
+        else
+            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_GRAYED);
+
+        return 0;
+
+    case WM_COMMAND:
+        hMenu = GetMenu (hwnd);
+
+        switch (LOWORD (wParam))
+        {
+        case IDM_FILE_OPEN:
+
+            /* show the File Open dialog box */
+
+            if (!PngFileOpenDlg (hwnd, szImgPathName, szTitleName))
+                return 0;
+
+            /* read the other png-files in the directory for later */
+            /* next/previous commands */
+
+            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
+                          &iPngFileIndex);
+
+            /* load the image from file */
+
+            if (!LoadImageFile (hwnd, szImgPathName,
+                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
+                return 0;
+
+            /* invalidate the client area for later update */
+
+            InvalidateRect (hwnd, NULL, TRUE);
+
+            /* display the PNG into the DIBitmap */
+
+            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+
+            return 0;
+
+        case IDM_FILE_SAVE:
+
+            /* show the File Save dialog box */
+
+            if (!PngFileSaveDlg (hwnd, szImgPathName, szTitleName))
+                return 0;
+
+            /* save the PNG to a disk file */
+
+            SetCursor (LoadCursor (NULL, IDC_WAIT));
+            ShowCursor (TRUE);
+
+            bOk = PngSaveImage (szImgPathName, pDiData, cxWinSize, cyWinSize,
+                  bkgColor);
+
+            ShowCursor (FALSE);
+            SetCursor (LoadCursor (NULL, IDC_ARROW));
+
+            if (!bOk)
+                MessageBox (hwnd, TEXT ("Error in saving the PNG image"),
+                szProgName, MB_ICONEXCLAMATION | MB_OK);
+            return 0;
+
+        case IDM_FILE_NEXT:
+
+            /* read next entry in the directory */
+
+            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
+                NULL, szImgPathName))
+            {
+                if (strcmp (szImgPathName, "") == 0)
+                    return 0;
+
+                /* load the image from file */
+
+                if (!LoadImageFile (hwnd, szImgPathName, &pbImage,
+                        &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
+                    return 0;
+
+                /* invalidate the client area for later update */
+
+                InvalidateRect (hwnd, NULL, TRUE);
+
+                /* display the PNG into the DIBitmap */
+
+                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+            }
+
+            return 0;
+
+        case IDM_FILE_PREVIOUS:
+
+            /* read previous entry in the directory */
+
+            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
+                szImgPathName, NULL))
+            {
+
+                if (strcmp (szImgPathName, "") == 0)
+                    return 0;
+
+                /* load the image from file */
+
+                if (!LoadImageFile (hwnd, szImgPathName, &pbImage, &cxImgSize,
+                    &cyImgSize, &cImgChannels, &bkgColor))
+                    return 0;
+
+                /* invalidate the client area for later update */
+
+                InvalidateRect (hwnd, NULL, TRUE);
+
+                /* display the PNG into the DIBitmap */
+
+                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+            }
+
+            return 0;
+
+        case IDM_FILE_EXIT:
+
+            /* more cleanup needed... */
+
+            /* free image buffer */
+
+            if (pDib != NULL)
+            {
+                free (pDib);
+                pDib = NULL;
+            }
+
+            /* free file-list */
+
+            if (pPngFileList != NULL)
+            {
+                free (pPngFileList);
+                pPngFileList = NULL;
+            }
+
+            /* let's go ... */
+
+            exit (0);
+
+            return 0;
+
+        case IDM_OPTIONS_STRETCH:
+            bStretched = !bStretched;
+            if (bStretched)
+                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_CHECKED);
+            else
+                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_UNCHECKED);
+
+            /* invalidate the client area for later update */
+
+            InvalidateRect (hwnd, NULL, TRUE);
+
+            /* display the PNG into the DIBitmap */
+
+            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+
+            return 0;
+
+        case IDM_HELP_ABOUT:
+            DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc) ;
+            return 0;
+
+        } /* end switch */
+
+        break;
+
+    case WM_PAINT:
+        hdc = BeginPaint (hwnd, &ps);
+
+        if (pDib)
+            SetDIBitsToDevice (hdc, 0, 0, cxWinSize, cyWinSize, 0, 0,
+                0, cyWinSize, pDiData, (BITMAPINFO *) pDib, DIB_RGB_COLORS);
+
+        EndPaint (hwnd, &ps);
+        return 0;
+
+    case WM_DESTROY:
+        if (pbmfh)
+        {
+            free (pbmfh);
+            pbmfh = NULL;
+        }
+
+        PostQuitMessage (0);
+        return 0;
+    }
+
+    return DefWindowProc (hwnd, message, wParam, lParam);
+}
+
+BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message,
+                            WPARAM wParam, LPARAM lParam)
+{
+     switch (message)
+     {
+     case WM_INITDIALOG :
+          ShowWindow (hDlg, SW_HIDE);
+          CenterAbout (hDlg, GetWindow (hDlg, GW_OWNER));
+          ShowWindow (hDlg, SW_SHOW);
+          return TRUE ;
+
+     case WM_COMMAND :
+          switch (LOWORD (wParam))
+          {
+          case IDOK :
+          case IDCANCEL :
+               EndDialog (hDlg, 0) ;
+               return TRUE ;
+          }
+          break ;
+     }
+     return FALSE ;
+}
+
+/*---------------
+ *  CenterAbout
+ *---------------
+ */
+BOOL CenterAbout (HWND hwndChild, HWND hwndParent)
+{
+   RECT    rChild, rParent, rWorkArea;
+   int     wChild, hChild, wParent, hParent;
+   int     xNew, yNew;
+   BOOL  bResult;
+
+   /* Get the Height and Width of the child window */
+   GetWindowRect (hwndChild, &rChild);
+   wChild = rChild.right - rChild.left;
+   hChild = rChild.bottom - rChild.top;
+
+   /* Get the Height and Width of the parent window */
+   GetWindowRect (hwndParent, &rParent);
+   wParent = rParent.right - rParent.left;
+   hParent = rParent.bottom - rParent.top;
+
+   /* Get the limits of the 'workarea' */
+   bResult = SystemParametersInfo(
+      SPI_GETWORKAREA,  /* system parameter to query or set */
+      sizeof(RECT),
+      &rWorkArea,
+      0);
+   if (!bResult) {
+      rWorkArea.left = rWorkArea.top = 0;
+      rWorkArea.right = GetSystemMetrics(SM_CXSCREEN);
+      rWorkArea.bottom = GetSystemMetrics(SM_CYSCREEN);
+   }
+
+   /* Calculate new X position, then adjust for workarea */
+   xNew = rParent.left + ((wParent - wChild) /2);
+   if (xNew < rWorkArea.left) {
+      xNew = rWorkArea.left;
+   } else if ((xNew+wChild) > rWorkArea.right) {
+      xNew = rWorkArea.right - wChild;
+   }
+
+   /* Calculate new Y position, then adjust for workarea */
+   yNew = rParent.top  + ((hParent - hChild) /2);
+   if (yNew < rWorkArea.top) {
+      yNew = rWorkArea.top;
+   } else if ((yNew+hChild) > rWorkArea.bottom) {
+      yNew = rWorkArea.bottom - hChild;
+   }
+
+   /* Set it, and return */
+   return SetWindowPos (hwndChild, NULL, xNew, yNew, 0, 0, SWP_NOSIZE |
+          SWP_NOZORDER);
+}
+
+/*----------------
+ *  BuildPngList
+ *----------------
+ */
+BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
+     int *pFileIndex)
+{
+    static TCHAR              szImgPathName [MAX_PATH];
+    static TCHAR              szImgFileName [MAX_PATH];
+    static TCHAR              szImgFindName [MAX_PATH];
+
+    WIN32_FIND_DATA           finddata;
+    HANDLE                    hFind;
+
+    static TCHAR              szTmp [MAX_PATH];
+    BOOL                      bOk;
+    int                       i, ii;
+    int                       j, jj;
+
+    /* free previous file-list */
+
+    if (*ppFileList != NULL)
+    {
+        free (*ppFileList);
+        *ppFileList = NULL;
+    }
+
+    /* extract foldername, filename and search-name */
+
+    strcpy (szImgPathName, pstrPathName);
+    strcpy (szImgFileName, strrchr (pstrPathName, '\\') + 1);
+
+    strcpy (szImgFindName, szImgPathName);
+    *(strrchr (szImgFindName, '\\') + 1) = '\0';
+    strcat (szImgFindName, "*.png");
+
+    /* first cycle: count number of files in directory for memory allocation */
+
+    *pFileCount = 0;
+
+    hFind = FindFirstFile(szImgFindName, &finddata);
+    bOk = (hFind != (HANDLE) -1);
+
+    while (bOk)
+    {
+        *pFileCount += 1;
+        bOk = FindNextFile(hFind, &finddata);
+    }
+    FindClose(hFind);
+
+    /* allocation memory for file-list */
+
+    *ppFileList = (TCHAR *) malloc (*pFileCount * MAX_PATH);
+
+    /* second cycle: read directory and store filenames in file-list */
+
+    hFind = FindFirstFile(szImgFindName, &finddata);
+    bOk = (hFind != (HANDLE) -1);
+
+    i = 0;
+    ii = 0;
+    while (bOk)
+    {
+        strcpy (*ppFileList + ii, szImgPathName);
+        strcpy (strrchr(*ppFileList + ii, '\\') + 1, finddata.cFileName);
+
+        if (strcmp(pstrPathName, *ppFileList + ii) == 0)
+            *pFileIndex = i;
+
+        ii += MAX_PATH;
+        i++;
+
+        bOk = FindNextFile(hFind, &finddata);
+    }
+    FindClose(hFind);
+
+    /* finally we must sort the file-list */
+
+    for (i = 0; i < *pFileCount - 1; i++)
+    {
+        ii = i * MAX_PATH;
+        for (j = i+1; j < *pFileCount; j++)
+        {
+            jj = j * MAX_PATH;
+            if (strcmp (*ppFileList + ii, *ppFileList + jj) > 0)
+            {
+                strcpy (szTmp, *ppFileList + jj);
+                strcpy (*ppFileList + jj, *ppFileList + ii);
+                strcpy (*ppFileList + ii, szTmp);
+
+                /* check if this was the current image that we moved */
+
+                if (*pFileIndex == i)
+                    *pFileIndex = j;
+                else
+                    if (*pFileIndex == j)
+                        *pFileIndex = i;
+            }
+        }
+    }
+
+    return TRUE;
+}
+
+/*----------------
+ *  SearchPngList
+ *----------------
+ */
+
+BOOL SearchPngList (
+        TCHAR *pFileList, int FileCount, int *pFileIndex,
+        PTSTR pstrPrevName, PTSTR pstrNextName)
+{
+    if (FileCount > 0)
+    {
+        /* get previous entry */
+
+        if (pstrPrevName != NULL)
+        {
+            if (*pFileIndex > 0)
+                *pFileIndex -= 1;
+            else
+                *pFileIndex = FileCount - 1;
+
+            strcpy (pstrPrevName, pFileList + (*pFileIndex * MAX_PATH));
+        }
+
+        /* get next entry */
+
+        if (pstrNextName != NULL)
+        {
+            if (*pFileIndex < FileCount - 1)
+                *pFileIndex += 1;
+            else
+                *pFileIndex = 0;
+
+            strcpy (pstrNextName, pFileList + (*pFileIndex * MAX_PATH));
+        }
+
+        return TRUE;
+    }
+    else
+    {
+        return FALSE;
+    }
+}
+
+/*-----------------
+ *  LoadImageFile
+ *-----------------
+ */
+
+BOOL LoadImageFile (HWND hwnd, PTSTR pstrPathName,
+                png_byte **ppbImage, int *pxImgSize, int *pyImgSize,
+                int *piChannels, png_color *pBkgColor)
+{
+    static TCHAR szTmp [MAX_PATH];
+
+    /* if there's an existing PNG, free the memory */
+
+    if (*ppbImage)
+    {
+        free (*ppbImage);
+        *ppbImage = NULL;
+    }
+
+    /* Load the entire PNG into memory */
+
+    SetCursor (LoadCursor (NULL, IDC_WAIT));
+    ShowCursor (TRUE);
+
+    PngLoadImage (pstrPathName, ppbImage, pxImgSize, pyImgSize, piChannels,
+                  pBkgColor);
+
+    ShowCursor (FALSE);
+    SetCursor (LoadCursor (NULL, IDC_ARROW));
+
+    if (*ppbImage != NULL)
+    {
+        sprintf (szTmp, "VisualPng - %s", strrchr(pstrPathName, '\\') + 1);
+        SetWindowText (hwnd, szTmp);
+    }
+    else
+    {
+        MessageBox (hwnd, TEXT ("Error in loading the PNG image"),
+            szProgName, MB_ICONEXCLAMATION | MB_OK);
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+/*----------------
+ *  DisplayImage
+ *----------------
+ */
+BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
+        BYTE **ppDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched)
+{
+    BYTE                       *pDib = *ppDib;
+    BYTE                       *pDiData = *ppDiData;
+    /* BITMAPFILEHEADER        *pbmfh; */
+    BITMAPINFOHEADER           *pbmih;
+    WORD                        wDIRowBytes;
+    png_color                   bkgBlack = {0, 0, 0};
+    png_color                   bkgGray  = {127, 127, 127};
+    png_color                   bkgWhite = {255, 255, 255};
+
+    /* allocate memory for the Device Independent bitmap */
+
+    wDIRowBytes = (WORD) ((3 * cxWinSize + 3L) >> 2) << 2;
+
+    if (pDib)
+    {
+        free (pDib);
+        pDib = NULL;
+    }
+
+    if (cyWinSize > ((size_t)(-1))/wDIRowBytes) {
+    {
+        MessageBox (hwnd, TEXT ("Visual PNG: image is too big");
+    }
+    if (!(pDib = (BYTE *) malloc (sizeof(BITMAPINFOHEADER) +
+        wDIRowBytes * cyWinSize)))
+    {
+        MessageBox (hwnd, TEXT ("Error in displaying the PNG image"),
+            szProgName, MB_ICONEXCLAMATION | MB_OK);
+        *ppDib = pDib = NULL;
+        return FALSE;
+    }
+    *ppDib = pDib;
+    memset (pDib, 0, sizeof(BITMAPINFOHEADER));
+
+    /* initialize the dib-structure */
+
+    pbmih = (BITMAPINFOHEADER *) pDib;
+    pbmih->biSize = sizeof(BITMAPINFOHEADER);
+    pbmih->biWidth = cxWinSize;
+    pbmih->biHeight = -((long) cyWinSize);
+    pbmih->biPlanes = 1;
+    pbmih->biBitCount = 24;
+    pbmih->biCompression = 0;
+    pDiData = pDib + sizeof(BITMAPINFOHEADER);
+    *ppDiData = pDiData;
+
+    /* first fill bitmap with gray and image border */
+
+    InitBitmap (pDiData, cxWinSize, cyWinSize);
+
+    /* then fill bitmap with image */
+
+    if (pbImage)
+    {
+        FillBitmap (
+            pDiData, cxWinSize, cyWinSize,
+            pbImage, cxImgSize, cyImgSize, cImgChannels,
+            bStretched);
+    }
+
+    return TRUE;
+}
+
+/*--------------
+ *  InitBitmap
+ *--------------
+ */
+BOOL InitBitmap (BYTE *pDiData, int cxWinSize, int cyWinSize)
+{
+    BYTE *dst;
+    int x, y, col;
+
+    /* initialize the background with gray */
+
+    dst = pDiData;
+    for (y = 0; y < cyWinSize; y++)
+    {
+        col = 0;
+        for (x = 0; x < cxWinSize; x++)
+        {
+            /* fill with GRAY */
+            *dst++ = 127;
+            *dst++ = 127;
+            *dst++ = 127;
+            col += 3;
+        }
+        /* rows start on 4 byte boundaries */
+        while ((col % 4) != 0)
+        {
+            dst++;
+            col++;
+        }
+    }
+
+    return TRUE;
+}
+
+/*--------------
+ *  FillBitmap
+ *--------------
+ */
+BOOL FillBitmap (
+        BYTE *pDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched)
+{
+    BYTE *pStretchedImage;
+    BYTE *pImg;
+    BYTE *src, *dst;
+    BYTE r, g, b, a;
+    const int cDIChannels = 3;
+    WORD wImgRowBytes;
+    WORD wDIRowBytes;
+    int cxNewSize, cyNewSize;
+    int cxImgPos, cyImgPos;
+    int xImg, yImg;
+    int xWin, yWin;
+    int xOld, yOld;
+    int xNew, yNew;
+
+    if (bStretched)
+    {
+        cxNewSize = cxWinSize - 2 * MARGIN;
+        cyNewSize = cyWinSize - 2 * MARGIN;
+
+        /* stretch the image to it's window determined size */
+
+        /* the following two are mathematically the same, but the first
+         * has side-effects because of rounding
+         */
+/*      if ((cyNewSize / cxNewSize) > (cyImgSize / cxImgSize)) */
+        if ((cyNewSize * cxImgSize) > (cyImgSize * cxNewSize))
+        {
+            cyNewSize = cxNewSize * cyImgSize / cxImgSize;
+            cxImgPos = MARGIN;
+            cyImgPos = (cyWinSize - cyNewSize) / 2;
+        }
+        else
+        {
+            cxNewSize = cyNewSize * cxImgSize / cyImgSize;
+            cyImgPos = MARGIN;
+            cxImgPos = (cxWinSize - cxNewSize) / 2;
+        }
+
+        if (cyNewSize > ((size_t)(-1))/(cImgChannels * cxNewSize)) {
+        {
+            MessageBox (hwnd, TEXT ("Visual PNG: stretched image is too big");
+        }
+        pStretchedImage = malloc (cImgChannels * cxNewSize * cyNewSize);
+        pImg = pStretchedImage;
+
+        for (yNew = 0; yNew < cyNewSize; yNew++)
+        {
+            yOld = yNew * cyImgSize / cyNewSize;
+            for (xNew = 0; xNew < cxNewSize; xNew++)
+            {
+                xOld = xNew * cxImgSize / cxNewSize;
+
+                r = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 0);
+                g = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 1);
+                b = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 2);
+                *pImg++ = r;
+                *pImg++ = g;
+                *pImg++ = b;
+                if (cImgChannels == 4)
+                {
+                    a = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld)
+                        + 3);
+                    *pImg++ = a;
+                }
+            }
+        }
+
+        /* calculate row-bytes */
+
+        wImgRowBytes = cImgChannels * cxNewSize;
+        wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
+
+        /* copy image to screen */
+
+        for (yImg = 0, yWin = cyImgPos; yImg < cyNewSize; yImg++, yWin++)
+        {
+            if (yWin >= cyWinSize - cyImgPos)
+                break;
+            src = pStretchedImage + yImg * wImgRowBytes;
+            dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
+
+            for (xImg = 0, xWin = cxImgPos; xImg < cxNewSize; xImg++, xWin++)
+            {
+                if (xWin >= cxWinSize - cxImgPos)
+                    break;
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dst++ = b; /* note the reverse order  */
+                *dst++ = g;
+                *dst++ = r;
+                if (cImgChannels == 4)
+                {
+                    a = *src++;
+                }
+            }
+        }
+
+        /* free memory */
+
+        if (pStretchedImage != NULL)
+        {
+            free (pStretchedImage);
+            pStretchedImage = NULL;
+        }
+
+    }
+
+    /* process the image not-stretched */
+
+    else
+    {
+        /* calculate the central position */
+
+        cxImgPos = (cxWinSize - cxImgSize) / 2;
+        cyImgPos = (cyWinSize - cyImgSize) / 2;
+
+        /* check for image larger than window */
+
+        if (cxImgPos < MARGIN)
+            cxImgPos = MARGIN;
+        if (cyImgPos < MARGIN)
+            cyImgPos = MARGIN;
+
+        /* calculate both row-bytes */
+
+        wImgRowBytes = cImgChannels * cxImgSize;
+        wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
+
+        /* copy image to screen */
+
+        for (yImg = 0, yWin = cyImgPos; yImg < cyImgSize; yImg++, yWin++)
+        {
+            if (yWin >= cyWinSize - MARGIN)
+                break;
+            src = pbImage + yImg * wImgRowBytes;
+            dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
+
+            for (xImg = 0, xWin = cxImgPos; xImg < cxImgSize; xImg++, xWin++)
+            {
+                if (xWin >= cxWinSize - MARGIN)
+                    break;
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dst++ = b; /* note the reverse order  */
+                *dst++ = g;
+                *dst++ = r;
+                if (cImgChannels == 4)
+                {
+                    a = *src++;
+                }
+            }
+        }
+    }
+
+    return TRUE;
+}
+
+/*-----------------
+ *  end of source
+ *-----------------
+ */
diff --git a/extern/libpng/contrib/visupng/VisualPng.dsp b/extern/libpng/contrib/visupng/VisualPng.dsp
new file mode 100644
index 0000000000..741ef6ce76
--- /dev/null
+++ b/extern/libpng/contrib/visupng/VisualPng.dsp
@@ -0,0 +1,147 @@
+# Microsoft Developer Studio Project File - Name="VisualPng" - Package Owner=<4>
+# Microsoft Developer Studio Generated Build File, Format Version 6.00
+# ** DO NOT EDIT **
+
+# TARGTYPE "Win32 (x86) Application" 0x0101
+
+CFG=VisualPng - Win32 Debug
+!MESSAGE This is not a valid makefile. To build this project using NMAKE,
+!MESSAGE use the Export Makefile command and run
+!MESSAGE 
+!MESSAGE NMAKE /f "VisualPng.mak".
+!MESSAGE 
+!MESSAGE You can specify a configuration when running NMAKE
+!MESSAGE by defining the macro CFG on the command line. For example:
+!MESSAGE 
+!MESSAGE NMAKE /f "VisualPng.mak" CFG="VisualPng - Win32 Debug"
+!MESSAGE 
+!MESSAGE Possible choices for configuration are:
+!MESSAGE 
+!MESSAGE "VisualPng - Win32 Release" (based on "Win32 (x86) Application")
+!MESSAGE "VisualPng - Win32 Debug" (based on "Win32 (x86) Application")
+!MESSAGE 
+
+# Begin Project
+# PROP AllowPerConfigDependencies 0
+# PROP Scc_ProjName ""
+# PROP Scc_LocalPath ""
+CPP=cl.exe
+MTL=midl.exe
+RSC=rc.exe
+
+!IF  "$(CFG)" == "VisualPng - Win32 Release"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 0
+# PROP BASE Output_Dir "Release"
+# PROP BASE Intermediate_Dir "Release"
+# PROP BASE Ignore_Export_Lib 0
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 0
+# PROP Output_Dir "Release"
+# PROP Intermediate_Dir "Release"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /W3 /O2 /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "NDEBUG" /D "PNG_NO_STDIO" /FD /c
+# SUBTRACT BASE CPP /YX
+# ADD CPP /nologo /MD /W3 /O2 /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "NDEBUG" /D "PNG_NO_STDIO" /FD /c
+# SUBTRACT CPP /YX
+# ADD BASE MTL /nologo /D "NDEBUG" /mktyplib203 /win32
+# ADD MTL /nologo /D "NDEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x409 /d "NDEBUG"
+# ADD RSC /l 0x409 /d "NDEBUG"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /machine:I386
+# ADD LINK32 ..\..\projects\visualc6\Win32_LIB_Release\libpng.lib ..\..\..\zlib\projects\visualc6\Win32_LIB_Release\zlib.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /machine:I386
+# Begin Special Build Tool
+OutDir=.\Release
+SOURCE="$(InputPath)"
+PostBuild_Cmds=$(outdir)\VisualPng.exe ..\..\contrib\pngsuite\basn6a16.png
+# End Special Build Tool
+
+!ELSEIF  "$(CFG)" == "VisualPng - Win32 Debug"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 1
+# PROP BASE Output_Dir "Debug"
+# PROP BASE Intermediate_Dir "Debug"
+# PROP BASE Ignore_Export_Lib 0
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 1
+# PROP Output_Dir "Debug"
+# PROP Intermediate_Dir "Debug"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /W3 /Gm /ZI /Od /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "_DEBUG" /D "PNG_NO_STDIO" /FD /GZ /c
+# SUBTRACT BASE CPP /YX
+# ADD CPP /nologo /MDd /W3 /Gm /ZI /Od /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "_DEBUG" /D "PNG_NO_STDIO" /FD /GZ /c
+# SUBTRACT CPP /YX
+# ADD BASE MTL /nologo /D "_DEBUG" /mktyplib203 /win32
+# ADD MTL /nologo /D "_DEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x409 /d "_DEBUG"
+# ADD RSC /l 0x409 /d "_DEBUG"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /debug /machine:I386 /pdbtype:sept
+# ADD LINK32 ..\..\projects\visualc6\Win32_LIB_Release\libpng.lib ..\..\..\zlib\projects\visualc6\Win32_LIB_Release\zlib.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /debug /machine:I386 /nodefaultlib:"msvcrt.lib" /pdbtype:sept
+# Begin Special Build Tool
+OutDir=.\Debug
+SOURCE="$(InputPath)"
+PostBuild_Cmds=$(outdir)\VisualPng.exe ..\..\contrib\pngsuite\basn6a16.png
+# End Special Build Tool
+
+!ENDIF 
+
+# Begin Target
+
+# Name "VisualPng - Win32 Release"
+# Name "VisualPng - Win32 Debug"
+# Begin Group "Source Files"
+
+# PROP Default_Filter "cpp;c;cxx;rc;def;r;odl;idl;hpj;bat"
+# Begin Source File
+
+SOURCE=.\PngFile.c
+# End Source File
+# Begin Source File
+
+SOURCE=.\VisualPng.c
+# End Source File
+# End Group
+# Begin Group "Header Files"
+
+# PROP Default_Filter "h;hpp;hxx;hm;inl"
+# Begin Source File
+
+SOURCE=.\cexcept.h
+# End Source File
+# Begin Source File
+
+SOURCE=.\PngFile.h
+# End Source File
+# Begin Source File
+
+SOURCE=.\resource.h
+# End Source File
+# End Group
+# Begin Group "Resource Files"
+
+# PROP Default_Filter "ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe"
+# Begin Source File
+
+SOURCE=.\VisualPng.ico
+# End Source File
+# Begin Source File
+
+SOURCE=.\VisualPng.rc
+# End Source File
+# End Group
+# End Target
+# End Project
diff --git a/extern/libpng/contrib/visupng/VisualPng.dsw b/extern/libpng/contrib/visupng/VisualPng.dsw
new file mode 100644
index 0000000000..a30e1cc1cd
--- /dev/null
+++ b/extern/libpng/contrib/visupng/VisualPng.dsw
@@ -0,0 +1,29 @@
+Microsoft Developer Studio Workspace File, Format Version 6.00
+# WARNING: DO NOT EDIT OR DELETE THIS WORKSPACE FILE!
+
+###############################################################################
+
+Project: "VisualPng"=.\VisualPng.dsp - Package Owner=<4>
+
+Package=<5>
+{{{
+}}}
+
+Package=<4>
+{{{
+}}}
+
+###############################################################################
+
+Global:
+
+Package=<5>
+{{{
+}}}
+
+Package=<3>
+{{{
+}}}
+
+###############################################################################
+
diff --git a/extern/libpng/contrib/visupng/VisualPng.ico b/extern/libpng/contrib/visupng/VisualPng.ico
new file mode 100644
index 0000000000000000000000000000000000000000..68aa3719fb523eccd4c4a706e4198ca1be2b4c62
GIT binary patch
literal 766
zcmb_ayGjE=6ul!BJ4Il&5f%%#i;YeE0sqBX?6q(TQ7j^}<v?10VbiXK*cmJrWrHY0
zA!dpc7D2{ycPG(^jp(^^ALqVy29`)b(o_-Sd4*^VeiNEPcc6k+VFA>Bh9<%xts4i6
zkcy&!=Yp>fdCw6P!YMX?g~S3@L(=jS0+)s|N<R6S5r&)Qb!)g04N`MXQq7T*R)b~W
znk>iKlEgL>VOVf)WTfR)85V$RN>JwSV-vWY^X3AQl6o~-A`A21P`H#(L`ua<kb=M>
zC6p2|SPTx|B;lEdR<4J97z(@|!YJx7#d!1r3hTe|MU4Yo<afY7umtC-4d;3T=aM()
z)~BP%-RxmpUOv5)v&rtgAGNEa$M$f0ygxi$8VsbmKHjRzi|)-;zIT4xZ=DSC*L>P<
Ob-aH+fF44>&V2wPTAUpK

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/visupng/VisualPng.png b/extern/libpng/contrib/visupng/VisualPng.png
new file mode 100644
index 0000000000000000000000000000000000000000..c6aa80a9bfa275137e429498bc785cb2dbcdb382
GIT binary patch
literal 208
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnL3?x0byx0z;SkfJR9T^xl_H+M9WCils0(?ST
zf%J9`j>RRx2|yNONswPKgTu2MX+Tbfr;B5V#O34!2UcDl9v_~y3Xga?K0NvO<H!Nc
z2bxC$Ry>|~WI+Z?ismL3#z>)ClO+n69&&Pt@)((moHOva6OfZ2FlX_Z0}8s!jvZ1^
zUz2uRL2<>QLkbEXTG%~o9y17?WOH!($Y?g1Vbg3Ozf`fCd_X%HJYD@<);T3K0RUGo
BL5BbU

literal 0
HcmV?d00001

diff --git a/extern/libpng/contrib/visupng/VisualPng.rc b/extern/libpng/contrib/visupng/VisualPng.rc
new file mode 100644
index 0000000000..6e0623a73c
--- /dev/null
+++ b/extern/libpng/contrib/visupng/VisualPng.rc
@@ -0,0 +1,152 @@
+//Microsoft Developer Studio generated resource script.
+//
+#include "resource.h"
+
+#define APSTUDIO_READONLY_SYMBOLS
+/////////////////////////////////////////////////////////////////////////////
+//
+// Generated from the TEXTINCLUDE 2 resource.
+//
+#include "afxres.h"
+
+/////////////////////////////////////////////////////////////////////////////
+#undef APSTUDIO_READONLY_SYMBOLS
+
+/////////////////////////////////////////////////////////////////////////////
+// English (U.S.) resources
+
+#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)
+#ifdef _WIN32
+LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
+#pragma code_page(1252)
+#endif //_WIN32
+
+#ifdef APSTUDIO_INVOKED
+/////////////////////////////////////////////////////////////////////////////
+//
+// TEXTINCLUDE
+//
+
+1 TEXTINCLUDE DISCARDABLE 
+BEGIN
+    "resource.h\0"
+END
+
+2 TEXTINCLUDE DISCARDABLE 
+BEGIN
+    "#include ""afxres.h""\r\n"
+    "\0"
+END
+
+3 TEXTINCLUDE DISCARDABLE 
+BEGIN
+    "\r\n"
+    "\0"
+END
+
+#endif    // APSTUDIO_INVOKED
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Menu
+//
+
+VISUALPNG MENU DISCARDABLE 
+BEGIN
+    POPUP "&File"
+    BEGIN
+        MENUITEM "&Open Image...\tCtrl+O",      IDM_FILE_OPEN
+        MENUITEM "Save &As...",                 IDM_FILE_SAVE
+        MENUITEM SEPARATOR
+        MENUITEM "&Next Image\tCtrl+N",         IDM_FILE_NEXT
+        MENUITEM "Pre&vious Image\tCtrl+V",     IDM_FILE_PREVIOUS
+        MENUITEM SEPARATOR
+        MENUITEM "E&xit\tAlt+X",                IDM_FILE_EXIT
+    END
+    POPUP "&Options"
+    BEGIN
+        MENUITEM "&Stretch",                    IDM_OPTIONS_STRETCH, CHECKED
+    END
+    POPUP "&Help"
+    BEGIN
+        MENUITEM "&About",                      IDM_HELP_ABOUT
+    END
+END
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Accelerator
+//
+
+VISUALPNG ACCELERATORS DISCARDABLE 
+BEGIN
+    "N",            IDM_FILE_NEXT,          VIRTKEY, CONTROL, NOINVERT
+    "O",            IDM_FILE_OPEN,          VIRTKEY, CONTROL, NOINVERT
+    "P",            IDM_FILE_PREVIOUS,      VIRTKEY, CONTROL, NOINVERT
+    "V",            IDM_FILE_PREVIOUS,      VIRTKEY, CONTROL, NOINVERT
+    "X",            IDM_FILE_EXIT,          VIRTKEY, ALT, NOINVERT
+END
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Icon
+//
+
+// Icon with lowest ID value placed first to ensure application icon
+// remains consistent on all systems.
+VISUALPNG               ICON    DISCARDABLE     "VisualPng.ico"
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Dialog
+//
+
+ABOUTBOX DIALOG DISCARDABLE  0, 0, 186, 94
+STYLE DS_MODALFRAME | WS_POPUP
+FONT 8, "MS Sans Serif"
+BEGIN
+    DEFPUSHBUTTON   "OK",IDOK,68,67,50,14
+    CTEXT           "VisualPng 1.0  -  June 2000",IDC_STATIC,49,14,88,8
+    LTEXT           "a PNG image viewer",IDC_STATIC,60,30,66,8
+    LTEXT           "(c) Willem van Schaik, 2000",IDC_STATIC,48,52,90,8
+    LTEXT           "to demonstrate the use of libpng in Visual C",
+                    IDC_STATIC,25,38,136,8
+END
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// DESIGNINFO
+//
+
+#ifdef APSTUDIO_INVOKED
+GUIDELINES DESIGNINFO DISCARDABLE 
+BEGIN
+    "ABOUTBOX", DIALOG
+    BEGIN
+        LEFTMARGIN, 7
+        RIGHTMARGIN, 179
+        TOPMARGIN, 7
+        BOTTOMMARGIN, 87
+    END
+END
+#endif    // APSTUDIO_INVOKED
+
+#endif    // English (U.S.) resources
+/////////////////////////////////////////////////////////////////////////////
+
+
+
+#ifndef APSTUDIO_INVOKED
+/////////////////////////////////////////////////////////////////////////////
+//
+// Generated from the TEXTINCLUDE 3 resource.
+//
+
+
+/////////////////////////////////////////////////////////////////////////////
+#endif    // not APSTUDIO_INVOKED
+
diff --git a/extern/libpng/contrib/visupng/cexcept.h b/extern/libpng/contrib/visupng/cexcept.h
new file mode 100644
index 0000000000..5f45d76975
--- /dev/null
+++ b/extern/libpng/contrib/visupng/cexcept.h
@@ -0,0 +1,248 @@
+/*===
+cexcept.h 2.0.1 (2008-Jul-19-Sat)
+http://www.nicemice.net/cexcept/
+Adam M. Costello
+http://www.nicemice.net/amc/
+
+An interface for exception-handling in ANSI C (C89 and subsequent ISO
+standards), developed jointly with Cosmin Truta.
+
+    Copyright (c) 2000-2008 Adam M. Costello and Cosmin Truta.
+    This software may be modified only if its author and version
+    information is updated accurately, and may be redistributed
+    only if accompanied by this unaltered notice.  Subject to those
+    restrictions, permission is granted to anyone to do anything
+    with this software.  The copyright holders make no guarantees
+    regarding this software, and are not responsible for any damage
+    resulting from its use.
+
+The cexcept interface is not compatible with and cannot interact
+with system exceptions (like division by zero or memory segmentation
+violation), compiler-generated exceptions (like C++ exceptions), or
+other exception-handling interfaces.
+
+When using this interface across multiple .c files, do not include
+this header file directly.  Instead, create a wrapper header file that
+includes this header file and then invokes the define_exception_type
+macro (see below).  The .c files should then include that header file.
+
+The interface consists of one type, one well-known name, and six macros.
+
+
+define_exception_type(type_name);
+
+    This macro is used like an external declaration.  It specifies
+    the type of object that gets copied from the exception thrower to
+    the exception catcher.  The type_name can be any type that can be
+    assigned to, that is, a non-constant arithmetic type, struct, union,
+    or pointer.  Examples:
+
+        define_exception_type(int);
+
+        enum exception { out_of_memory, bad_arguments, disk_full };
+        define_exception_type(enum exception);
+
+        struct exception { int code; const char *msg; };
+        define_exception_type(struct exception);
+
+    Because throwing an exception causes the object to be copied (not
+    just once, but twice), programmers may wish to consider size when
+    choosing the exception type.
+
+
+struct exception_context;
+
+    This type may be used after the define_exception_type() macro has
+    been invoked.  A struct exception_context must be known to both
+    the thrower and the catcher.  It is expected that there be one
+    context for each thread that uses exceptions.  It would certainly
+    be dangerous for multiple threads to access the same context.
+    One thread can use multiple contexts, but that is likely to be
+    confusing and not typically useful.  The application can allocate
+    this structure in any way it pleases--automatic, static, or dynamic.
+    The application programmer should pretend not to know the structure
+    members, which are subject to change.
+
+
+struct exception_context *the_exception_context;
+
+    The Try/Catch and Throw statements (described below) implicitly
+    refer to a context, using the name the_exception_context.  It is
+    the application's responsibility to make sure that this name yields
+    the address of a mutable (non-constant) struct exception_context
+    wherever those statements are used.  Subject to that constraint, the
+    application may declare a variable of this name anywhere it likes
+    (inside a function, in a parameter list, or externally), and may
+    use whatever storage class specifiers (static, extern, etc) or type
+    qualifiers (const, volatile, etc) it likes.  Examples:
+
+        static struct exception_context
+          * const the_exception_context = &foo;
+
+        { struct exception_context *the_exception_context = bar; ... }
+
+        int blah(struct exception_context *the_exception_context, ...);
+
+        extern struct exception_context the_exception_context[1];
+
+    The last example illustrates a trick that avoids creating a pointer
+    object separate from the structure object.
+
+    The name could even be a macro, for example:
+
+        struct exception_context ec_array[numthreads];
+        #define the_exception_context (ec_array + thread_id)
+
+    Be aware that the_exception_context is used several times by the
+    Try/Catch/Throw macros, so it shouldn't be expensive or have side
+    effects.  The expansion must be a drop-in replacement for an
+    identifier, so it's safest to put parentheses around it.
+
+
+void init_exception_context(struct exception_context *ec);
+
+    For context structures allocated statically (by an external
+    definition or using the "static" keyword), the implicit
+    initialization to all zeros is sufficient, but contexts allocated
+    by other means must be initialized using this macro before they
+    are used by a Try/Catch statement.  It does no harm to initialize
+    a context more than once (by using this macro on a statically
+    allocated context, or using this macro twice on the same context),
+    but a context must not be re-initialized after it has been used by a
+    Try/Catch statement.
+
+
+Try statement
+Catch (expression) statement
+
+    The Try/Catch/Throw macros are capitalized in order to avoid
+    confusion with the C++ keywords, which have subtly different
+    semantics.
+
+    A Try/Catch statement has a syntax similar to an if/else statement,
+    except that the parenthesized expression goes after the second
+    keyword rather than the first.  As with if/else, there are two
+    clauses, each of which may be a simple statement ending with a
+    semicolon or a brace-enclosed compound statement.  But whereas
+    the else clause is optional, the Catch clause is required.  The
+    expression must be a modifiable lvalue (something capable of being
+    assigned to) of the same type (disregarding type qualifiers) that
+    was passed to define_exception_type().
+
+    If a Throw that uses the same exception context as the Try/Catch is
+    executed within the Try clause (typically within a function called
+    by the Try clause), and the exception is not caught by a nested
+    Try/Catch statement, then a copy of the exception will be assigned
+    to the expression, and control will jump to the Catch clause.  If no
+    such Throw is executed, then the assignment is not performed, and
+    the Catch clause is not executed.
+
+    The expression is not evaluated unless and until the exception is
+    caught, which is significant if it has side effects, for example:
+
+        Try foo();
+        Catch (p[++i].e) { ... }
+
+    IMPORTANT: Jumping into or out of a Try clause (for example via
+    return, break, continue, goto, longjmp) is forbidden--the compiler
+    will not complain, but bad things will happen at run-time.  Jumping
+    into or out of a Catch clause is okay, and so is jumping around
+    inside a Try clause.  In many cases where one is tempted to return
+    from a Try clause, it will suffice to use Throw, and then return
+    from the Catch clause.  Another option is to set a flag variable and
+    use goto to jump to the end of the Try clause, then check the flag
+    after the Try/Catch statement.
+
+    IMPORTANT: The values of any non-volatile automatic variables
+    changed within the Try clause are undefined after an exception is
+    caught.  Therefore, variables modified inside the Try block whose
+    values are needed later outside the Try block must either use static
+    storage or be declared with the "volatile" type qualifier.
+
+
+Throw expression;
+
+    A Throw statement is very much like a return statement, except that
+    the expression is required.  Whereas return jumps back to the place
+    where the current function was called, Throw jumps back to the Catch
+    clause of the innermost enclosing Try clause.  The expression must
+    be compatible with the type passed to define_exception_type().  The
+    exception must be caught, otherwise the program may crash.
+
+    Slight limitation:  If the expression is a comma-expression, it must
+    be enclosed in parentheses.
+
+
+Try statement
+Catch_anonymous statement
+
+    When the value of the exception is not needed, a Try/Catch statement
+    can use Catch_anonymous instead of Catch (expression).
+
+
+Everything below this point is for the benefit of the compiler.  The
+application programmer should pretend not to know any of it, because it
+is subject to change.
+
+===*/
+
+
+#ifndef CEXCEPT_H
+#define CEXCEPT_H
+
+
+#include <setjmp.h>
+
+#define define_exception_type(etype) \
+struct exception_context { \
+  jmp_buf *penv; \
+  int caught; \
+  volatile struct { etype etmp; } v; \
+}
+
+/* etmp must be volatile because the application might use automatic */
+/* storage for the_exception_context, and etmp is modified between   */
+/* the calls to setjmp() and longjmp().  A wrapper struct is used to */
+/* avoid warnings about a duplicate volatile qualifier in case etype */
+/* already includes it.                                              */
+
+#define init_exception_context(ec) ((void)((ec)->penv = 0))
+
+#define Try \
+  { \
+    jmp_buf *exception__prev, exception__env; \
+    exception__prev = the_exception_context->penv; \
+    the_exception_context->penv = &exception__env; \
+    if (setjmp(exception__env) == 0) { \
+      do
+
+#define exception__catch(action) \
+      while (the_exception_context->caught = 0, \
+             the_exception_context->caught); \
+    } \
+    else { \
+      the_exception_context->caught = 1; \
+    } \
+    the_exception_context->penv = exception__prev; \
+  } \
+  if (!the_exception_context->caught || action) { } \
+  else
+
+#define Catch(e) exception__catch(((e) = the_exception_context->v.etmp, 0))
+#define Catch_anonymous exception__catch(0)
+
+/* Try ends with do, and Catch begins with while(0) and ends with     */
+/* else, to ensure that Try/Catch syntax is similar to if/else        */
+/* syntax.                                                            */
+/*                                                                    */
+/* The 0 in while(0) is expressed as x=0,x in order to appease        */
+/* compilers that warn about constant expressions inside while().     */
+/* Most compilers should still recognize that the condition is always */
+/* false and avoid generating code for it.                            */
+
+#define Throw \
+  for (;; longjmp(*the_exception_context->penv, 1)) \
+    the_exception_context->v.etmp =
+
+
+#endif /* CEXCEPT_H */
diff --git a/extern/libpng/contrib/visupng/resource.h b/extern/libpng/contrib/visupng/resource.h
new file mode 100644
index 0000000000..b62176d1dc
--- /dev/null
+++ b/extern/libpng/contrib/visupng/resource.h
@@ -0,0 +1,23 @@
+//{{NO_DEPENDENCIES}}
+// Microsoft Developer Studio generated include file.
+// Used by VisualPng.rc
+//
+#define IDM_FILE_OPEN                   40001
+#define IDM_FILE_SAVE                   40002
+#define IDM_FILE_NEXT                   40003
+#define IDM_FILE_PREVIOUS               40004
+#define IDM_FILE_EXIT                   40005
+#define IDM_OPTIONS_BACKGROUND          40006
+#define IDM_OPTIONS_STRETCH             40007
+#define IDM_HELP_ABOUT                  40008
+
+// Next default values for new objects
+//
+#ifdef APSTUDIO_INVOKED
+#ifndef APSTUDIO_READONLY_SYMBOLS
+#define _APS_NEXT_RESOURCE_VALUE        113
+#define _APS_NEXT_COMMAND_VALUE         40009
+#define _APS_NEXT_CONTROL_VALUE         1001
+#define _APS_NEXT_SYMED_VALUE           101
+#endif
+#endif
diff --git a/extern/libpng/depcomp b/extern/libpng/depcomp
new file mode 100755
index 0000000000..65cbf7093a
--- /dev/null
+++ b/extern/libpng/depcomp
@@ -0,0 +1,791 @@
+#! /bin/sh
+# depcomp - compile a program generating dependencies as side-effects
+
+scriptversion=2018-03-07.03; # UTC
+
+# Copyright (C) 1999-2018 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# Originally written by Alexandre Oliva <oliva@dcc.unicamp.br>.
+
+case $1 in
+  '')
+    echo "$0: No command.  Try '$0 --help' for more information." 1>&2
+    exit 1;
+    ;;
+  -h | --h*)
+    cat <<\EOF
+Usage: depcomp [--help] [--version] PROGRAM [ARGS]
+
+Run PROGRAMS ARGS to compile a file, generating dependencies
+as side-effects.
+
+Environment variables:
+  depmode     Dependency tracking mode.
+  source      Source file read by 'PROGRAMS ARGS'.
+  object      Object file output by 'PROGRAMS ARGS'.
+  DEPDIR      directory where to store dependencies.
+  depfile     Dependency file to output.
+  tmpdepfile  Temporary file to use when outputting dependencies.
+  libtool     Whether libtool is used (yes/no).
+
+Report bugs to <bug-automake@gnu.org>.
+EOF
+    exit $?
+    ;;
+  -v | --v*)
+    echo "depcomp $scriptversion"
+    exit $?
+    ;;
+esac
+
+# Get the directory component of the given path, and save it in the
+# global variables '$dir'.  Note that this directory component will
+# be either empty or ending with a '/' character.  This is deliberate.
+set_dir_from ()
+{
+  case $1 in
+    */*) dir=`echo "$1" | sed -e 's|/[^/]*$|/|'`;;
+      *) dir=;;
+  esac
+}
+
+# Get the suffix-stripped basename of the given path, and save it the
+# global variable '$base'.
+set_base_from ()
+{
+  base=`echo "$1" | sed -e 's|^.*/||' -e 's/\.[^.]*$//'`
+}
+
+# If no dependency file was actually created by the compiler invocation,
+# we still have to create a dummy depfile, to avoid errors with the
+# Makefile "include basename.Plo" scheme.
+make_dummy_depfile ()
+{
+  echo "#dummy" > "$depfile"
+}
+
+# Factor out some common post-processing of the generated depfile.
+# Requires the auxiliary global variable '$tmpdepfile' to be set.
+aix_post_process_depfile ()
+{
+  # If the compiler actually managed to produce a dependency file,
+  # post-process it.
+  if test -f "$tmpdepfile"; then
+    # Each line is of the form 'foo.o: dependency.h'.
+    # Do two passes, one to just change these to
+    #   $object: dependency.h
+    # and one to simply output
+    #   dependency.h:
+    # which is needed to avoid the deleted-header problem.
+    { sed -e "s,^.*\.[$lower]*:,$object:," < "$tmpdepfile"
+      sed -e "s,^.*\.[$lower]*:[$tab ]*,," -e 's,$,:,' < "$tmpdepfile"
+    } > "$depfile"
+    rm -f "$tmpdepfile"
+  else
+    make_dummy_depfile
+  fi
+}
+
+# A tabulation character.
+tab='	'
+# A newline character.
+nl='
+'
+# Character ranges might be problematic outside the C locale.
+# These definitions help.
+upper=ABCDEFGHIJKLMNOPQRSTUVWXYZ
+lower=abcdefghijklmnopqrstuvwxyz
+digits=0123456789
+alpha=${upper}${lower}
+
+if test -z "$depmode" || test -z "$source" || test -z "$object"; then
+  echo "depcomp: Variables source, object and depmode must be set" 1>&2
+  exit 1
+fi
+
+# Dependencies for sub/bar.o or sub/bar.obj go into sub/.deps/bar.Po.
+depfile=${depfile-`echo "$object" |
+  sed 's|[^\\/]*$|'${DEPDIR-.deps}'/&|;s|\.\([^.]*\)$|.P\1|;s|Pobj$|Po|'`}
+tmpdepfile=${tmpdepfile-`echo "$depfile" | sed 's/\.\([^.]*\)$/.T\1/'`}
+
+rm -f "$tmpdepfile"
+
+# Avoid interferences from the environment.
+gccflag= dashmflag=
+
+# Some modes work just like other modes, but use different flags.  We
+# parameterize here, but still list the modes in the big case below,
+# to make depend.m4 easier to write.  Note that we *cannot* use a case
+# here, because this file can only contain one case statement.
+if test "$depmode" = hp; then
+  # HP compiler uses -M and no extra arg.
+  gccflag=-M
+  depmode=gcc
+fi
+
+if test "$depmode" = dashXmstdout; then
+  # This is just like dashmstdout with a different argument.
+  dashmflag=-xM
+  depmode=dashmstdout
+fi
+
+cygpath_u="cygpath -u -f -"
+if test "$depmode" = msvcmsys; then
+  # This is just like msvisualcpp but w/o cygpath translation.
+  # Just convert the backslash-escaped backslashes to single forward
+  # slashes to satisfy depend.m4
+  cygpath_u='sed s,\\\\,/,g'
+  depmode=msvisualcpp
+fi
+
+if test "$depmode" = msvc7msys; then
+  # This is just like msvc7 but w/o cygpath translation.
+  # Just convert the backslash-escaped backslashes to single forward
+  # slashes to satisfy depend.m4
+  cygpath_u='sed s,\\\\,/,g'
+  depmode=msvc7
+fi
+
+if test "$depmode" = xlc; then
+  # IBM C/C++ Compilers xlc/xlC can output gcc-like dependency information.
+  gccflag=-qmakedep=gcc,-MF
+  depmode=gcc
+fi
+
+case "$depmode" in
+gcc3)
+## gcc 3 implements dependency tracking that does exactly what
+## we want.  Yay!  Note: for some reason libtool 1.4 doesn't like
+## it if -MD -MP comes after the -MF stuff.  Hmm.
+## Unfortunately, FreeBSD c89 acceptance of flags depends upon
+## the command line argument order; so add the flags where they
+## appear in depend2.am.  Note that the slowdown incurred here
+## affects only configure: in makefiles, %FASTDEP% shortcuts this.
+  for arg
+  do
+    case $arg in
+    -c) set fnord "$@" -MT "$object" -MD -MP -MF "$tmpdepfile" "$arg" ;;
+    *)  set fnord "$@" "$arg" ;;
+    esac
+    shift # fnord
+    shift # $arg
+  done
+  "$@"
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  mv "$tmpdepfile" "$depfile"
+  ;;
+
+gcc)
+## Note that this doesn't just cater to obsosete pre-3.x GCC compilers.
+## but also to in-use compilers like IMB xlc/xlC and the HP C compiler.
+## (see the conditional assignment to $gccflag above).
+## There are various ways to get dependency output from gcc.  Here's
+## why we pick this rather obscure method:
+## - Don't want to use -MD because we'd like the dependencies to end
+##   up in a subdir.  Having to rename by hand is ugly.
+##   (We might end up doing this anyway to support other compilers.)
+## - The DEPENDENCIES_OUTPUT environment variable makes gcc act like
+##   -MM, not -M (despite what the docs say).  Also, it might not be
+##   supported by the other compilers which use the 'gcc' depmode.
+## - Using -M directly means running the compiler twice (even worse
+##   than renaming).
+  if test -z "$gccflag"; then
+    gccflag=-MD,
+  fi
+  "$@" -Wp,"$gccflag$tmpdepfile"
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+  echo "$object : \\" > "$depfile"
+  # The second -e expression handles DOS-style file names with drive
+  # letters.
+  sed -e 's/^[^:]*: / /' \
+      -e 's/^['$alpha']:\/[^:]*: / /' < "$tmpdepfile" >> "$depfile"
+## This next piece of magic avoids the "deleted header file" problem.
+## The problem is that when a header file which appears in a .P file
+## is deleted, the dependency causes make to die (because there is
+## typically no way to rebuild the header).  We avoid this by adding
+## dummy dependencies for each header file.  Too bad gcc doesn't do
+## this for us directly.
+## Some versions of gcc put a space before the ':'.  On the theory
+## that the space means something, we add a space to the output as
+## well.  hp depmode also adds that space, but also prefixes the VPATH
+## to the object.  Take care to not repeat it in the output.
+## Some versions of the HPUX 10.20 sed can't process this invocation
+## correctly.  Breaking it into two sed invocations is a workaround.
+  tr ' ' "$nl" < "$tmpdepfile" \
+    | sed -e 's/^\\$//' -e '/^$/d' -e "s|.*$object$||" -e '/:$/d' \
+    | sed -e 's/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+hp)
+  # This case exists only to let depend.m4 do its work.  It works by
+  # looking at the text of this script.  This case will never be run,
+  # since it is checked for above.
+  exit 1
+  ;;
+
+sgi)
+  if test "$libtool" = yes; then
+    "$@" "-Wp,-MDupdate,$tmpdepfile"
+  else
+    "$@" -MDupdate "$tmpdepfile"
+  fi
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+
+  if test -f "$tmpdepfile"; then  # yes, the sourcefile depend on other files
+    echo "$object : \\" > "$depfile"
+    # Clip off the initial element (the dependent).  Don't try to be
+    # clever and replace this with sed code, as IRIX sed won't handle
+    # lines with more than a fixed number of characters (4096 in
+    # IRIX 6.2 sed, 8192 in IRIX 6.5).  We also remove comment lines;
+    # the IRIX cc adds comments like '#:fec' to the end of the
+    # dependency line.
+    tr ' ' "$nl" < "$tmpdepfile" \
+      | sed -e 's/^.*\.o://' -e 's/#.*$//' -e '/^$/ d' \
+      | tr "$nl" ' ' >> "$depfile"
+    echo >> "$depfile"
+    # The second pass generates a dummy entry for each header file.
+    tr ' ' "$nl" < "$tmpdepfile" \
+      | sed -e 's/^.*\.o://' -e 's/#.*$//' -e '/^$/ d' -e 's/$/:/' \
+      >> "$depfile"
+  else
+    make_dummy_depfile
+  fi
+  rm -f "$tmpdepfile"
+  ;;
+
+xlc)
+  # This case exists only to let depend.m4 do its work.  It works by
+  # looking at the text of this script.  This case will never be run,
+  # since it is checked for above.
+  exit 1
+  ;;
+
+aix)
+  # The C for AIX Compiler uses -M and outputs the dependencies
+  # in a .u file.  In older versions, this file always lives in the
+  # current directory.  Also, the AIX compiler puts '$object:' at the
+  # start of each line; $object doesn't have directory information.
+  # Version 6 uses the directory in both cases.
+  set_dir_from "$object"
+  set_base_from "$object"
+  if test "$libtool" = yes; then
+    tmpdepfile1=$dir$base.u
+    tmpdepfile2=$base.u
+    tmpdepfile3=$dir.libs/$base.u
+    "$@" -Wc,-M
+  else
+    tmpdepfile1=$dir$base.u
+    tmpdepfile2=$dir$base.u
+    tmpdepfile3=$dir$base.u
+    "$@" -M
+  fi
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
+    exit $stat
+  fi
+
+  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
+  do
+    test -f "$tmpdepfile" && break
+  done
+  aix_post_process_depfile
+  ;;
+
+tcc)
+  # tcc (Tiny C Compiler) understand '-MD -MF file' since version 0.9.26
+  # FIXME: That version still under development at the moment of writing.
+  #        Make that this statement remains true also for stable, released
+  #        versions.
+  # It will wrap lines (doesn't matter whether long or short) with a
+  # trailing '\', as in:
+  #
+  #   foo.o : \
+  #    foo.c \
+  #    foo.h \
+  #
+  # It will put a trailing '\' even on the last line, and will use leading
+  # spaces rather than leading tabs (at least since its commit 0394caf7
+  # "Emit spaces for -MD").
+  "$@" -MD -MF "$tmpdepfile"
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+  # Each non-empty line is of the form 'foo.o : \' or ' dep.h \'.
+  # We have to change lines of the first kind to '$object: \'.
+  sed -e "s|.*:|$object :|" < "$tmpdepfile" > "$depfile"
+  # And for each line of the second kind, we have to emit a 'dep.h:'
+  # dummy dependency, to avoid the deleted-header problem.
+  sed -n -e 's|^  *\(.*\) *\\$|\1:|p' < "$tmpdepfile" >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+## The order of this option in the case statement is important, since the
+## shell code in configure will try each of these formats in the order
+## listed in this file.  A plain '-MD' option would be understood by many
+## compilers, so we must ensure this comes after the gcc and icc options.
+pgcc)
+  # Portland's C compiler understands '-MD'.
+  # Will always output deps to 'file.d' where file is the root name of the
+  # source file under compilation, even if file resides in a subdirectory.
+  # The object file name does not affect the name of the '.d' file.
+  # pgcc 10.2 will output
+  #    foo.o: sub/foo.c sub/foo.h
+  # and will wrap long lines using '\' :
+  #    foo.o: sub/foo.c ... \
+  #     sub/foo.h ... \
+  #     ...
+  set_dir_from "$object"
+  # Use the source, not the object, to determine the base name, since
+  # that's sadly what pgcc will do too.
+  set_base_from "$source"
+  tmpdepfile=$base.d
+
+  # For projects that build the same source file twice into different object
+  # files, the pgcc approach of using the *source* file root name can cause
+  # problems in parallel builds.  Use a locking strategy to avoid stomping on
+  # the same $tmpdepfile.
+  lockdir=$base.d-lock
+  trap "
+    echo '$0: caught signal, cleaning up...' >&2
+    rmdir '$lockdir'
+    exit 1
+  " 1 2 13 15
+  numtries=100
+  i=$numtries
+  while test $i -gt 0; do
+    # mkdir is a portable test-and-set.
+    if mkdir "$lockdir" 2>/dev/null; then
+      # This process acquired the lock.
+      "$@" -MD
+      stat=$?
+      # Release the lock.
+      rmdir "$lockdir"
+      break
+    else
+      # If the lock is being held by a different process, wait
+      # until the winning process is done or we timeout.
+      while test -d "$lockdir" && test $i -gt 0; do
+        sleep 1
+        i=`expr $i - 1`
+      done
+    fi
+    i=`expr $i - 1`
+  done
+  trap - 1 2 13 15
+  if test $i -le 0; then
+    echo "$0: failed to acquire lock after $numtries attempts" >&2
+    echo "$0: check lockdir '$lockdir'" >&2
+    exit 1
+  fi
+
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+  # Each line is of the form `foo.o: dependent.h',
+  # or `foo.o: dep1.h dep2.h \', or ` dep3.h dep4.h \'.
+  # Do two passes, one to just change these to
+  # `$object: dependent.h' and one to simply `dependent.h:'.
+  sed "s,^[^:]*:,$object :," < "$tmpdepfile" > "$depfile"
+  # Some versions of the HPUX 10.20 sed can't process this invocation
+  # correctly.  Breaking it into two sed invocations is a workaround.
+  sed 's,^[^:]*: \(.*\)$,\1,;s/^\\$//;/^$/d;/:$/d' < "$tmpdepfile" \
+    | sed -e 's/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+hp2)
+  # The "hp" stanza above does not work with aCC (C++) and HP's ia64
+  # compilers, which have integrated preprocessors.  The correct option
+  # to use with these is +Maked; it writes dependencies to a file named
+  # 'foo.d', which lands next to the object file, wherever that
+  # happens to be.
+  # Much of this is similar to the tru64 case; see comments there.
+  set_dir_from  "$object"
+  set_base_from "$object"
+  if test "$libtool" = yes; then
+    tmpdepfile1=$dir$base.d
+    tmpdepfile2=$dir.libs/$base.d
+    "$@" -Wc,+Maked
+  else
+    tmpdepfile1=$dir$base.d
+    tmpdepfile2=$dir$base.d
+    "$@" +Maked
+  fi
+  stat=$?
+  if test $stat -ne 0; then
+     rm -f "$tmpdepfile1" "$tmpdepfile2"
+     exit $stat
+  fi
+
+  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2"
+  do
+    test -f "$tmpdepfile" && break
+  done
+  if test -f "$tmpdepfile"; then
+    sed -e "s,^.*\.[$lower]*:,$object:," "$tmpdepfile" > "$depfile"
+    # Add 'dependent.h:' lines.
+    sed -ne '2,${
+               s/^ *//
+               s/ \\*$//
+               s/$/:/
+               p
+             }' "$tmpdepfile" >> "$depfile"
+  else
+    make_dummy_depfile
+  fi
+  rm -f "$tmpdepfile" "$tmpdepfile2"
+  ;;
+
+tru64)
+  # The Tru64 compiler uses -MD to generate dependencies as a side
+  # effect.  'cc -MD -o foo.o ...' puts the dependencies into 'foo.o.d'.
+  # At least on Alpha/Redhat 6.1, Compaq CCC V6.2-504 seems to put
+  # dependencies in 'foo.d' instead, so we check for that too.
+  # Subdirectories are respected.
+  set_dir_from  "$object"
+  set_base_from "$object"
+
+  if test "$libtool" = yes; then
+    # Libtool generates 2 separate objects for the 2 libraries.  These
+    # two compilations output dependencies in $dir.libs/$base.o.d and
+    # in $dir$base.o.d.  We have to check for both files, because
+    # one of the two compilations can be disabled.  We should prefer
+    # $dir$base.o.d over $dir.libs/$base.o.d because the latter is
+    # automatically cleaned when .libs/ is deleted, while ignoring
+    # the former would cause a distcleancheck panic.
+    tmpdepfile1=$dir$base.o.d          # libtool 1.5
+    tmpdepfile2=$dir.libs/$base.o.d    # Likewise.
+    tmpdepfile3=$dir.libs/$base.d      # Compaq CCC V6.2-504
+    "$@" -Wc,-MD
+  else
+    tmpdepfile1=$dir$base.d
+    tmpdepfile2=$dir$base.d
+    tmpdepfile3=$dir$base.d
+    "$@" -MD
+  fi
+
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
+    exit $stat
+  fi
+
+  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
+  do
+    test -f "$tmpdepfile" && break
+  done
+  # Same post-processing that is required for AIX mode.
+  aix_post_process_depfile
+  ;;
+
+msvc7)
+  if test "$libtool" = yes; then
+    showIncludes=-Wc,-showIncludes
+  else
+    showIncludes=-showIncludes
+  fi
+  "$@" $showIncludes > "$tmpdepfile"
+  stat=$?
+  grep -v '^Note: including file: ' "$tmpdepfile"
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+  echo "$object : \\" > "$depfile"
+  # The first sed program below extracts the file names and escapes
+  # backslashes for cygpath.  The second sed program outputs the file
+  # name when reading, but also accumulates all include files in the
+  # hold buffer in order to output them again at the end.  This only
+  # works with sed implementations that can handle large buffers.
+  sed < "$tmpdepfile" -n '
+/^Note: including file:  *\(.*\)/ {
+  s//\1/
+  s/\\/\\\\/g
+  p
+}' | $cygpath_u | sort -u | sed -n '
+s/ /\\ /g
+s/\(.*\)/'"$tab"'\1 \\/p
+s/.\(.*\) \\/\1:/
+H
+$ {
+  s/.*/'"$tab"'/
+  G
+  p
+}' >> "$depfile"
+  echo >> "$depfile" # make sure the fragment doesn't end with a backslash
+  rm -f "$tmpdepfile"
+  ;;
+
+msvc7msys)
+  # This case exists only to let depend.m4 do its work.  It works by
+  # looking at the text of this script.  This case will never be run,
+  # since it is checked for above.
+  exit 1
+  ;;
+
+#nosideeffect)
+  # This comment above is used by automake to tell side-effect
+  # dependency tracking mechanisms from slower ones.
+
+dashmstdout)
+  # Important note: in order to support this mode, a compiler *must*
+  # always write the preprocessed file to stdout, regardless of -o.
+  "$@" || exit $?
+
+  # Remove the call to Libtool.
+  if test "$libtool" = yes; then
+    while test "X$1" != 'X--mode=compile'; do
+      shift
+    done
+    shift
+  fi
+
+  # Remove '-o $object'.
+  IFS=" "
+  for arg
+  do
+    case $arg in
+    -o)
+      shift
+      ;;
+    $object)
+      shift
+      ;;
+    *)
+      set fnord "$@" "$arg"
+      shift # fnord
+      shift # $arg
+      ;;
+    esac
+  done
+
+  test -z "$dashmflag" && dashmflag=-M
+  # Require at least two characters before searching for ':'
+  # in the target name.  This is to cope with DOS-style filenames:
+  # a dependency such as 'c:/foo/bar' could be seen as target 'c' otherwise.
+  "$@" $dashmflag |
+    sed "s|^[$tab ]*[^:$tab ][^:][^:]*:[$tab ]*|$object: |" > "$tmpdepfile"
+  rm -f "$depfile"
+  cat < "$tmpdepfile" > "$depfile"
+  # Some versions of the HPUX 10.20 sed can't process this sed invocation
+  # correctly.  Breaking it into two sed invocations is a workaround.
+  tr ' ' "$nl" < "$tmpdepfile" \
+    | sed -e 's/^\\$//' -e '/^$/d' -e '/:$/d' \
+    | sed -e 's/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+dashXmstdout)
+  # This case only exists to satisfy depend.m4.  It is never actually
+  # run, as this mode is specially recognized in the preamble.
+  exit 1
+  ;;
+
+makedepend)
+  "$@" || exit $?
+  # Remove any Libtool call
+  if test "$libtool" = yes; then
+    while test "X$1" != 'X--mode=compile'; do
+      shift
+    done
+    shift
+  fi
+  # X makedepend
+  shift
+  cleared=no eat=no
+  for arg
+  do
+    case $cleared in
+    no)
+      set ""; shift
+      cleared=yes ;;
+    esac
+    if test $eat = yes; then
+      eat=no
+      continue
+    fi
+    case "$arg" in
+    -D*|-I*)
+      set fnord "$@" "$arg"; shift ;;
+    # Strip any option that makedepend may not understand.  Remove
+    # the object too, otherwise makedepend will parse it as a source file.
+    -arch)
+      eat=yes ;;
+    -*|$object)
+      ;;
+    *)
+      set fnord "$@" "$arg"; shift ;;
+    esac
+  done
+  obj_suffix=`echo "$object" | sed 's/^.*\././'`
+  touch "$tmpdepfile"
+  ${MAKEDEPEND-makedepend} -o"$obj_suffix" -f"$tmpdepfile" "$@"
+  rm -f "$depfile"
+  # makedepend may prepend the VPATH from the source file name to the object.
+  # No need to regex-escape $object, excess matching of '.' is harmless.
+  sed "s|^.*\($object *:\)|\1|" "$tmpdepfile" > "$depfile"
+  # Some versions of the HPUX 10.20 sed can't process the last invocation
+  # correctly.  Breaking it into two sed invocations is a workaround.
+  sed '1,2d' "$tmpdepfile" \
+    | tr ' ' "$nl" \
+    | sed -e 's/^\\$//' -e '/^$/d' -e '/:$/d' \
+    | sed -e 's/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile" "$tmpdepfile".bak
+  ;;
+
+cpp)
+  # Important note: in order to support this mode, a compiler *must*
+  # always write the preprocessed file to stdout.
+  "$@" || exit $?
+
+  # Remove the call to Libtool.
+  if test "$libtool" = yes; then
+    while test "X$1" != 'X--mode=compile'; do
+      shift
+    done
+    shift
+  fi
+
+  # Remove '-o $object'.
+  IFS=" "
+  for arg
+  do
+    case $arg in
+    -o)
+      shift
+      ;;
+    $object)
+      shift
+      ;;
+    *)
+      set fnord "$@" "$arg"
+      shift # fnord
+      shift # $arg
+      ;;
+    esac
+  done
+
+  "$@" -E \
+    | sed -n -e '/^# [0-9][0-9]* "\([^"]*\)".*/ s:: \1 \\:p' \
+             -e '/^#line [0-9][0-9]* "\([^"]*\)".*/ s:: \1 \\:p' \
+    | sed '$ s: \\$::' > "$tmpdepfile"
+  rm -f "$depfile"
+  echo "$object : \\" > "$depfile"
+  cat < "$tmpdepfile" >> "$depfile"
+  sed < "$tmpdepfile" '/^$/d;s/^ //;s/ \\$//;s/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+msvisualcpp)
+  # Important note: in order to support this mode, a compiler *must*
+  # always write the preprocessed file to stdout.
+  "$@" || exit $?
+
+  # Remove the call to Libtool.
+  if test "$libtool" = yes; then
+    while test "X$1" != 'X--mode=compile'; do
+      shift
+    done
+    shift
+  fi
+
+  IFS=" "
+  for arg
+  do
+    case "$arg" in
+    -o)
+      shift
+      ;;
+    $object)
+      shift
+      ;;
+    "-Gm"|"/Gm"|"-Gi"|"/Gi"|"-ZI"|"/ZI")
+        set fnord "$@"
+        shift
+        shift
+        ;;
+    *)
+        set fnord "$@" "$arg"
+        shift
+        shift
+        ;;
+    esac
+  done
+  "$@" -E 2>/dev/null |
+  sed -n '/^#line [0-9][0-9]* "\([^"]*\)"/ s::\1:p' | $cygpath_u | sort -u > "$tmpdepfile"
+  rm -f "$depfile"
+  echo "$object : \\" > "$depfile"
+  sed < "$tmpdepfile" -n -e 's% %\\ %g' -e '/^\(.*\)$/ s::'"$tab"'\1 \\:p' >> "$depfile"
+  echo "$tab" >> "$depfile"
+  sed < "$tmpdepfile" -n -e 's% %\\ %g' -e '/^\(.*\)$/ s::\1\::p' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+msvcmsys)
+  # This case exists only to let depend.m4 do its work.  It works by
+  # looking at the text of this script.  This case will never be run,
+  # since it is checked for above.
+  exit 1
+  ;;
+
+none)
+  exec "$@"
+  ;;
+
+*)
+  echo "Unknown depmode $depmode" 1>&2
+  exit 1
+  ;;
+esac
+
+exit 0
+
+# Local Variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
diff --git a/extern/libpng/example.c b/extern/libpng/example.c
new file mode 100644
index 0000000000..2e2afaafb6
--- /dev/null
+++ b/extern/libpng/example.c
@@ -0,0 +1,1040 @@
+
+#if 0 /* in case someone actually tries to compile this */
+
+/* example.c - an example of using libpng
+ *
+ * Maintained 2018 Cosmin Truta
+ * Maintained 1998-2016 Glenn Randers-Pehrson
+ * Maintained 1996-1997 Andreas Dilger
+ * Written 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * To the extent possible under law, the authors have waived
+ * all copyright and related or neighboring rights to this file.
+ * This work is published from: United States, Canada.
+ */
+
+/* This is an example of how to use libpng to read and write PNG files.
+ * The file libpng-manual.txt is much more verbose then this.  If you have
+ * not read it, do so first.  This was designed to be a starting point of an
+ * implementation.  This is not officially part of libpng, is hereby placed
+ * in the public domain, and therefore does not require a copyright notice.
+ *
+ * This file does not currently compile, because it is missing certain
+ * parts, like allocating memory to hold an image.  You will have to
+ * supply these parts to get it to compile.  For an example of a minimal
+ * working PNG reader/writer, see pngtest.c, included in this distribution;
+ * see also the programs in the contrib directory.
+ */
+
+/* The simple, but restricted approach to reading a PNG file or data stream
+ * requires just two function calls, as in the following complete program.
+ * Writing a file needs just one function call, so long as the data has an
+ * appropriate layout.
+ *
+ * The following code reads PNG image data from a file and writes it, in a
+ * potentially new format, to a new file.  While this code will compile, there
+ * is minimal (insufficient) error checking.  For a more realistic version,
+ * see contrib/examples/pngtopng.c
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <png.h>
+#include <zlib.h>
+
+int main(int argc, const char **argv)
+{
+   if (argc == 3)
+   {
+      png_image image; /* The control structure used by libpng */
+
+      /* Initialize the 'png_image' structure. */
+      memset(&image, 0, (sizeof image));
+      image.version = PNG_IMAGE_VERSION;
+
+      /* The first argument is the file to read: */
+      if (png_image_begin_read_from_file(&image, argv[1]) != 0)
+      {
+         png_bytep buffer;
+
+         /* Set the format in which to read the PNG file; this code chooses a
+          * simple sRGB format with a non-associated alpha channel, adequate to
+          * store most images.
+          */
+         image.format = PNG_FORMAT_RGBA;
+
+         /* Now allocate enough memory to hold the image in this format; the
+          * PNG_IMAGE_SIZE macro uses the information about the image (width,
+          * height and format) stored in 'image'.
+          */
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         /* If enough memory was available, read the image in the desired
+          * format, then write the result out to the new file.  'background' is
+          * not necessary when reading the image, because the alpha channel is
+          * preserved; if it were to be removed, for example if we requested
+          * PNG_FORMAT_RGB, then either a solid background color would have to
+          * be supplied, or the output buffer would have to be initialized to
+          * the actual background of the image.
+          *
+          * The fourth argument to png_image_finish_read is the 'row_stride' -
+          * this is the number of components allocated for the image in each
+          * row.  It has to be at least as big as the value returned by
+          * PNG_IMAGE_ROW_STRIDE, but if you just allocate space for the
+          * default, minimum size, using PNG_IMAGE_SIZE as above, you can pass
+          * zero.
+          *
+          * The final argument is a pointer to a buffer for the colormap;
+          * colormaps have exactly the same format as a row of image pixels
+          * (so you choose what format to make the colormap by setting
+          * image.format).  A colormap is only returned if
+          * PNG_FORMAT_FLAG_COLORMAP is also set in image.format, so in this
+          * case NULL is passed as the final argument.  If you do want to force
+          * all images into an index/color-mapped format, then you can use:
+          *
+          *    PNG_IMAGE_COLORMAP_SIZE(image)
+          *
+          * to find the maximum size of the colormap in bytes.
+          */
+         if (buffer != NULL &&
+            png_image_finish_read(&image, NULL/*background*/, buffer,
+                0/*row_stride*/, NULL/*colormap*/) != 0)
+         {
+            /* Now write the image out to the second argument.  In the write
+             * call 'convert_to_8bit' allows 16-bit data to be squashed down to
+             * 8 bits; this isn't necessary here because the original read was
+             * to the 8-bit format.
+             */
+            if (png_image_write_to_file(&image, argv[2], 0/*convert_to_8bit*/,
+                buffer, 0/*row_stride*/, NULL/*colormap*/) != 0)
+            {
+               /* The image has been written successfully. */
+               exit(0);
+            }
+         }
+         else
+         {
+            /* Calling png_image_free is optional unless the simplified API was
+             * not run to completion.  In this case, if there wasn't enough
+             * memory for 'buffer', we didn't complete the read, so we must
+             * free the image:
+             */
+            if (buffer == NULL)
+               png_image_free(&image);
+            else
+               free(buffer);
+      }
+
+      /* Something went wrong reading or writing the image.  libpng stores a
+       * textual message in the 'png_image' structure:
+       */
+      fprintf(stderr, "pngtopng: error: %s\n", image.message);
+      exit(1);
+   }
+
+   fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n");
+   exit(2);
+}
+
+/* That's it ;-)  Of course you probably want to do more with PNG files than
+ * just converting them all to 32-bit RGBA PNG files; you can do that between
+ * the call to png_image_finish_read and png_image_write_to_file.  You can also
+ * ask for the image data to be presented in a number of different formats.
+ * You do this by simply changing the 'format' parameter set before allocating
+ * the buffer.
+ *
+ * The format parameter consists of five flags that define various aspects of
+ * the image.  You can simply add these together to get the format, or you can
+ * use one of the predefined macros from png.h (as above):
+ *
+ * PNG_FORMAT_FLAG_COLOR: if set, the image will have three color components
+ *    per pixel (red, green and blue); if not set, the image will just have one
+ *    luminance (grayscale) component.
+ *
+ * PNG_FORMAT_FLAG_ALPHA: if set, each pixel in the image will have an
+ *    additional alpha value; a linear value that describes the degree the
+ *    image pixel covers (overwrites) the contents of the existing pixel on the
+ *    display.
+ *
+ * PNG_FORMAT_FLAG_LINEAR: if set, the components of each pixel will be
+ *    returned as a series of 16-bit linear values; if not set, the components
+ *    will be returned as a series of 8-bit values encoded according to the
+ *    sRGB standard.  The 8-bit format is the normal format for images intended
+ *    for direct display, because almost all display devices do the inverse of
+ *    the sRGB transformation to the data they receive.  The 16-bit format is
+ *    more common for scientific data and image data that must be further
+ *    processed; because it is linear, simple math can be done on the component
+ *    values.  Regardless of the setting of this flag, the alpha channel is
+ *    always linear, although it will be 8 bits or 16 bits wide as specified by
+ *    the flag.
+ *
+ * PNG_FORMAT_FLAG_BGR: if set, the components of a color pixel will be
+ *    returned in the order blue, then green, then red.  If not set, the pixel
+ *    components are in the order red, then green, then blue.
+ *
+ * PNG_FORMAT_FLAG_AFIRST: if set, the alpha channel (if present) precedes the
+ *    color or grayscale components.  If not set, the alpha channel follows the
+ *    components.
+ *
+ * You do not have to read directly from a file.  You can read from memory or,
+ * on systems that support it, from a <stdio.h> FILE*.  This is controlled by
+ * the particular png_image_read_from_ function you call at the start.
+ * Likewise, on write, you can write to a FILE* if your system supports it.
+ * Check the macro PNG_STDIO_SUPPORTED to see if stdio support has been
+ * included in your libpng build.
+ *
+ * If you read 16-bit (PNG_FORMAT_FLAG_LINEAR) data, you may need to write it
+ * in the 8-bit format for display.  You do this by setting the convert_to_8bit
+ * flag to 'true'.
+ *
+ * Don't repeatedly convert between the 8-bit and 16-bit forms.  There is
+ * significant data loss when 16-bit data is converted to the 8-bit encoding,
+ * and the current libpng implementation of conversion to 16-bit is also
+ * significantly lossy.  The latter will be fixed in the future, but the former
+ * is unavoidable - the 8-bit format just doesn't have enough resolution.
+ */
+
+/* If your program needs more information from the PNG data it reads, or if you
+ * need to do more complex transformations, or minimize transformations, on the
+ * data you read, then you must use one of the several lower level libpng
+ * interfaces.
+ *
+ * All these interfaces require that you do your own error handling - your
+ * program must be able to arrange for control to return to your own code, any
+ * time libpng encounters a problem.  There are several ways to do this, but
+ * the standard way is to use the <setjmp.h> interface to establish a return
+ * point within your own code.  You must do this if you do not use the
+ * simplified interface (above).
+ *
+ * The first step is to include the header files you need, including the libpng
+ * header file.  Include any standard headers and feature test macros your
+ * program requires before including png.h:
+ */
+#include <png.h>
+
+ /* The png_jmpbuf() macro, used in error handling, became available in
+  * libpng version 1.0.6.  If you want to be able to run your code with older
+  * versions of libpng, you must define the macro yourself (but only if it
+  * is not already defined by libpng!)
+  */
+
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr) ((png_ptr)->png_jmpbuf)
+#endif
+
+/* Check to see if a file is a PNG file using png_sig_cmp().  png_sig_cmp()
+ * returns zero if the image is a PNG, and nonzero otherwise.
+ *
+ * The function check_if_png() shown here, but not used, returns nonzero (true)
+ * if the file can be opened and is a PNG, and 0 (false) otherwise.
+ *
+ * If this call is successful, and you are going to keep the file open,
+ * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
+ * you have created the png_ptr, so that libpng knows your application
+ * has read that many bytes from the start of the file.  Make sure you
+ * don't call png_set_sig_bytes() with more than 8 bytes read or give it
+ * an incorrect number of bytes read, or you will either have read too
+ * many bytes (your fault), or you are telling libpng to read the wrong
+ * number of magic bytes (also your fault).
+ *
+ * Many applications already read the first 2 or 4 bytes from the start
+ * of the image to determine the file type, so it would be easiest just
+ * to pass the bytes to png_sig_cmp(), or even skip that if you know
+ * you have a PNG file, and call png_set_sig_bytes().
+ */
+#define PNG_BYTES_TO_CHECK 4
+int check_if_png(char *file_name, FILE **fp)
+{
+   char buf[PNG_BYTES_TO_CHECK];
+
+   /* Open the prospective PNG file. */
+   if ((*fp = fopen(file_name, "rb")) == NULL)
+      return 0;
+
+   /* Read in some of the signature bytes. */
+   if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK)
+      return 0;
+
+   /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
+    * Return nonzero (true) if they match.
+    */
+   return(!png_sig_cmp(buf, 0, PNG_BYTES_TO_CHECK));
+}
+
+/* Read a PNG file.  You may want to return an error code if the read
+ * fails (depending upon the failure).  There are two "prototypes" given
+ * here - one where we are given the filename, and we need to open the
+ * file, and the other where we are given an open file (possibly with
+ * some or all of the magic bytes read - see comments above).
+ */
+#ifdef open_file /* prototype 1 */
+void read_png(char *file_name) /* We need to open the file */
+{
+   png_structp png_ptr;
+   png_infop info_ptr;
+   int sig_read = 0;
+   png_uint_32 width, height;
+   int bit_depth, color_type, interlace_type;
+   FILE *fp;
+
+   if ((fp = fopen(file_name, "rb")) == NULL)
+      return (ERROR);
+
+#else no_open_file /* prototype 2 */
+void read_png(FILE *fp, int sig_read) /* File is already open */
+{
+   png_structp png_ptr;
+   png_infop info_ptr;
+   png_uint_32 width, height;
+   int bit_depth, color_type, interlace_type;
+#endif no_open_file /* Only use one prototype! */
+
+   /* Create and initialize the png_struct with the desired error handler
+    * functions.  If you want to use the default stderr and longjump method,
+    * you can supply NULL for the last three parameters.  We also supply the
+    * the compiler header file version, so that we know if the application
+    * was compiled with a compatible version of the library.  REQUIRED.
+    */
+   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+       png_voidp user_error_ptr, user_error_fn, user_warning_fn);
+
+   if (png_ptr == NULL)
+   {
+      fclose(fp);
+      return (ERROR);
+   }
+
+   /* Allocate/initialize the memory for image information.  REQUIRED. */
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+   {
+      fclose(fp);
+      png_destroy_read_struct(&png_ptr, NULL, NULL);
+      return (ERROR);
+   }
+
+   /* Set error handling if you are using the setjmp/longjmp method (this is
+    * the normal method of doing things with libpng).  REQUIRED unless you
+    * set up your own error handlers in the png_create_read_struct() earlier.
+    */
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      /* Free all of the memory associated with the png_ptr and info_ptr. */
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      fclose(fp);
+      /* If we get here, we had a problem reading the file. */
+      return (ERROR);
+   }
+
+   /* One of the following I/O initialization methods is REQUIRED. */
+#ifdef streams /* PNG file I/O method 1 */
+   /* Set up the input control if you are using standard C streams. */
+   png_init_io(png_ptr, fp);
+
+#else no_streams /* PNG file I/O method 2 */
+   /* If you are using replacement read functions, instead of calling
+    * png_init_io(), you would call:
+    */
+   png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
+   /* where user_io_ptr is a structure you want available to the callbacks. */
+#endif no_streams /* Use only one I/O method! */
+
+   /* If we have already read some of the signature */
+   png_set_sig_bytes(png_ptr, sig_read);
+
+#ifdef hilevel
+   /* If you have enough memory to read in the entire image at once,
+    * and you need to specify only transforms that can be controlled
+    * with one of the PNG_TRANSFORM_* bits (this presently excludes
+    * quantizing, filling, setting background, and doing gamma
+    * adjustment), then you can read the entire image (including
+    * pixels) into the info structure with this call:
+    */
+   png_read_png(png_ptr, info_ptr, png_transforms, NULL);
+
+#else
+   /* OK, you're doing it the hard way, with the lower-level functions. */
+
+   /* The call to png_read_info() gives us all of the information from the
+    * PNG file before the first IDAT (image data chunk).  REQUIRED.
+    */
+   png_read_info(png_ptr, info_ptr);
+
+   png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+       &interlace_type, NULL, NULL);
+
+   /* Set up the data transformations you want.  Note that these are all
+    * optional.  Only call them if you want/need them.  Many of the
+    * transformations only work on specific types of images, and many
+    * are mutually exclusive.
+    */
+
+   /* Tell libpng to strip 16 bits/color files down to 8 bits/color.
+    * Use accurate scaling if it's available, otherwise just chop off the
+    * low byte.
+    */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+   png_set_scale_16(png_ptr);
+#else
+   png_set_strip_16(png_ptr);
+#endif
+
+   /* Strip alpha bytes from the input data without combining with the
+    * background (not recommended).
+    */
+   png_set_strip_alpha(png_ptr);
+
+   /* Extract multiple pixels with bit depths of 1, 2 or 4 from a single
+    * byte into separate bytes (useful for paletted and grayscale images).
+    */
+   png_set_packing(png_ptr);
+
+   /* Change the order of packed pixels to least significant bit first
+    * (not useful if you are using png_set_packing).
+    */
+   png_set_packswap(png_ptr);
+
+   /* Expand paletted colors into true RGB triplets. */
+   if (color_type == PNG_COLOR_TYPE_PALETTE)
+      png_set_palette_to_rgb(png_ptr);
+
+   /* Expand grayscale images to the full 8 bits from 1, 2 or 4 bits/pixel. */
+   if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+      png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+   /* Expand paletted or RGB images with transparency to full alpha channels
+    * so the data will be available as RGBA quartets.
+    */
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) != 0)
+      png_set_tRNS_to_alpha(png_ptr);
+
+   /* Set the background color to draw transparent and alpha images over.
+    * It is possible to set the red, green and blue components directly
+    * for paletted images, instead of supplying a palette index.  Note that,
+    * even if the PNG file supplies a background, you are not required to
+    * use it - you should use the (solid) application background if it has one.
+    */
+   png_color_16 my_background, *image_background;
+
+   if (png_get_bKGD(png_ptr, info_ptr, &image_background) != 0)
+      png_set_background(png_ptr, image_background,
+          PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+   else
+      png_set_background(png_ptr, &my_background,
+          PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
+
+   /* Some suggestions as to how to get a screen gamma value.
+    *
+    * Note that screen gamma is the display_exponent, which includes
+    * the CRT_exponent and any correction for viewing conditions.
+    */
+   if (/* We have a user-defined screen gamma value */)
+      screen_gamma = user-defined screen_gamma;
+   /* This is one way that applications share the same screen gamma value. */
+   else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL)
+      screen_gamma = atof(gamma_str);
+   /* If we don't have another value */
+   else
+   {
+      screen_gamma = PNG_DEFAULT_sRGB; /* A good guess for a PC monitor
+                                          in a dimly lit room */
+      screen_gamma = PNG_GAMMA_MAC_18 or 1.0; /* Good guesses for Mac
+                                                 systems */
+   }
+
+   /* Tell libpng to handle the gamma conversion for you.  The final call
+    * is a good guess for PC generated images, but it should be configurable
+    * by the user at run time.  Gamma correction support in your application
+    * is strongly recommended.
+    */
+
+   int intent;
+
+   if (png_get_sRGB(png_ptr, info_ptr, &intent) != 0)
+      png_set_gamma(png_ptr, screen_gamma, PNG_DEFAULT_sRGB);
+   else
+   {
+      double image_gamma;
+      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma) != 0)
+         png_set_gamma(png_ptr, screen_gamma, image_gamma);
+      else
+         png_set_gamma(png_ptr, screen_gamma, 0.45455);
+   }
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   /* Quantize RGB files down to 8-bit palette, or reduce palettes
+    * to the number of colors available on your screen.
+    */
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      int num_palette;
+      png_colorp palette;
+
+      /* This reduces the image to the application-supplied palette. */
+      if (/* We have our own palette */)
+      {
+         /* An array of colors to which the image should be quantized. */
+         png_color std_color_cube[MAX_SCREEN_COLORS];
+         png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
+             MAX_SCREEN_COLORS, NULL, 0);
+      }
+      /* This reduces the image to the palette supplied in the file. */
+      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) != 0)
+      {
+         png_uint_16p histogram = NULL;
+         png_get_hIST(png_ptr, info_ptr, &histogram);
+         png_set_quantize(png_ptr, palette, num_palette,
+             max_screen_colors, histogram, 0);
+      }
+   }
+#endif /* READ_QUANTIZE */
+
+   /* Invert monochrome files to have 0 as white and 1 as black. */
+   png_set_invert_mono(png_ptr);
+
+   /* If you want to shift the pixel values from the range [0,255] or
+    * [0,65535] to the original [0,7] or [0,31], or whatever range the
+    * colors were originally in:
+    */
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT) != 0)
+   {
+      png_color_8p sig_bit_p;
+      png_get_sBIT(png_ptr, info_ptr, &sig_bit_p);
+      png_set_shift(png_ptr, sig_bit_p);
+   }
+
+   /* Flip the RGB pixels to BGR (or RGBA to BGRA). */
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+      png_set_bgr(png_ptr);
+
+   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR). */
+   png_set_swap_alpha(png_ptr);
+
+   /* Swap bytes of 16-bit files to least significant byte first. */
+   png_set_swap(png_ptr);
+
+   /* Add filler (or alpha) byte (before/after each RGB triplet). */
+   png_set_filler(png_ptr, 0xffff, PNG_FILLER_AFTER);
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* Turn on interlace handling.  REQUIRED if you are not using
+    * png_read_image().  To see how to handle interlacing passes,
+    * see the png_read_row() method below:
+    */
+   number_passes = png_set_interlace_handling(png_ptr);
+#else /* !READ_INTERLACING */
+   number_passes = 1;
+#endif /* READ_INTERLACING */
+
+   /* Optional call to gamma correct and add the background to the palette
+    * and update info structure.  REQUIRED if you are expecting libpng to
+    * update the palette for you (i.e. you selected such a transform above).
+    */
+   png_read_update_info(png_ptr, info_ptr);
+
+   /* Allocate the memory to hold the image using the fields of info_ptr. */
+   png_bytep row_pointers[height];
+   for (row = 0; row < height; row++)
+      row_pointers[row] = NULL; /* Clear the pointer array */
+   for (row = 0; row < height; row++)
+      row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
+          info_ptr));
+
+   /* Now it's time to read the image.  One of these methods is REQUIRED. */
+#ifdef entire /* Read the entire image in one go */
+   png_read_image(png_ptr, row_pointers);
+
+#else no_entire /* Read the image one or more scanlines at a time */
+   /* The other way to read images - deal with interlacing: */
+   for (pass = 0; pass < number_passes; pass++)
+   {
+#ifdef single /* Read the image a single row at a time */
+      for (y = 0; y < height; y++)
+         png_read_rows(png_ptr, &row_pointers[y], NULL, 1);
+
+#else no_single /* Read the image several rows at a time */
+      for (y = 0; y < height; y += number_of_rows)
+      {
+#ifdef sparkle /* Read the image using the "sparkle" effect. */
+         png_read_rows(png_ptr, &row_pointers[y], NULL,
+             number_of_rows);
+#else no_sparkle /* Read the image using the "rectangle" effect */
+         png_read_rows(png_ptr, NULL, &row_pointers[y],
+             number_of_rows);
+#endif no_sparkle /* Use only one of these two methods */
+      }
+
+      /* If you want to display the image after every pass, do so here. */
+#endif no_single /* Use only one of these two methods */
+   }
+#endif no_entire /* Use only one of these two methods */
+
+   /* Read rest of file, and get additional chunks in info_ptr.  REQUIRED. */
+   png_read_end(png_ptr, info_ptr);
+#endif hilevel
+
+   /* At this point you have read the entire image. */
+
+   /* Clean up after the read, and free any memory allocated.  REQUIRED. */
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+   /* Close the file. */
+   fclose(fp);
+
+   /* That's it! */
+   return (OK);
+}
+
+/* Progressively read a file */
+
+int
+initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
+{
+   /* Create and initialize the png_struct with the desired error handler
+    * functions.  If you want to use the default stderr and longjump method,
+    * you can supply NULL for the last three parameters.  We also check that
+    * the library version is compatible, in case we are using dynamically
+    * linked libraries.
+    */
+   *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+        png_voidp user_error_ptr, user_error_fn, user_warning_fn);
+   if (*png_ptr == NULL)
+   {
+      *info_ptr = NULL;
+      return (ERROR);
+   }
+   *info_ptr = png_create_info_struct(png_ptr);
+   if (*info_ptr == NULL)
+   {
+      png_destroy_read_struct(png_ptr, info_ptr, NULL);
+      return (ERROR);
+   }
+   if (setjmp(png_jmpbuf((*png_ptr))))
+   {
+      png_destroy_read_struct(png_ptr, info_ptr, NULL);
+      return (ERROR);
+   }
+
+   /* You will need to provide all three function callbacks,
+    * even if you aren't using all of them.
+    * If you aren't using all functions, you can specify NULL
+    * parameters.  Even when all three functions are NULL,
+    * you need to call png_set_progressive_read_fn().
+    * These functions shouldn't be dependent on global or
+    * static variables if you are decoding several images
+    * simultaneously.  You should store stream specific data
+    * in a separate struct, given as the second parameter,
+    * and retrieve the pointer from inside the callbacks using
+    * the function png_get_progressive_ptr(png_ptr).
+    */
+   png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
+       info_callback, row_callback, end_callback);
+   return (OK);
+}
+
+int
+process_data(png_structp *png_ptr, png_infop *info_ptr,
+    png_bytep buffer, png_uint_32 length)
+{
+   if (setjmp(png_jmpbuf((*png_ptr))))
+   {
+      /* Free the png_ptr and info_ptr memory on error. */
+      png_destroy_read_struct(png_ptr, info_ptr, NULL);
+      return (ERROR);
+   }
+
+   /* Give chunks of data as they arrive from the data stream
+    * (in order, of course).
+    * On segmented machines, don't give it any more than 64K.
+    * The library seems to run fine with sizes of 4K, although
+    * you can give it much less if necessary. (I assume you can
+    * give it chunks of 1 byte, but I haven't tried with less
+    * than 256 bytes yet.)  When this function returns, you may
+    * want to display any rows that were generated in the row
+    * callback, if you aren't already displaying them there.
+    */
+   png_process_data(*png_ptr, *info_ptr, buffer, length);
+   return (OK);
+}
+
+info_callback(png_structp png_ptr, png_infop info)
+{
+   /* Do any setup here, including setting any of the transformations
+    * mentioned in the Reading PNG files section.  For now, you _must_
+    * call either png_start_read_image() or png_read_update_info()
+    * after all the transformations are set (even if you don't set
+    * any).  You may start getting rows before png_process_data()
+    * returns, so this is your last chance to prepare for that.
+    */
+}
+
+row_callback(png_structp png_ptr, png_bytep new_row,
+    png_uint_32 row_num, int pass)
+{
+   /* This function is called for every row in the image.  If the
+    * image is interlaced, and you turned on the interlace handler,
+    * this function will be called for every row in every pass.
+    *
+    * In this function you will receive a pointer to new row data from
+    * libpng called new_row that is to replace a corresponding row (of
+    * the same data format) in a buffer allocated by your application.
+    *
+    * The new row data pointer "new_row" may be NULL, indicating there is
+    * no new data to be replaced (in cases of interlace loading).
+    *
+    * If new_row is not NULL, then you need to call
+    * png_progressive_combine_row(), to replace the corresponding row as
+    * shown below:
+    */
+
+   /* Get pointer to corresponding row in our PNG read buffer. */
+   png_bytep old_row = ((png_bytep *)our_data)[row_num];
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* If both rows are allocated, then copy the new row
+    * data to the corresponding row data.
+    */
+   if (old_row != NULL && new_row != NULL)
+      png_progressive_combine_row(png_ptr, old_row, new_row);
+
+   /* The rows and passes are called in order, so you don't really
+    * need the row_num and pass, but I'm supplying them because it
+    * may make your life easier.
+    *
+    * For the non-NULL rows of interlaced images, you must call
+    * png_progressive_combine_row() passing in the new row and the
+    * old row, as demonstrated above.  You can call this function for
+    * NULL rows (it will just return) and for non-interlaced images
+    * (it just does the memcpy for you) if it will make the code
+    * easier.  Thus, you can just do this for all cases:
+    */
+   png_progressive_combine_row(png_ptr, old_row, new_row);
+
+   /* where old_row is what was displayed for previous rows.  Note
+    * that the first pass (pass == 0 really) will completely cover
+    * the old row, so the rows do not have to be initialized.  After
+    * the first pass (and only for interlaced images), you will have
+    * to pass the current row as new_row, and the function will combine
+    * the old row and the new row.
+    */
+#endif /* READ_INTERLACING */
+}
+
+end_callback(png_structp png_ptr, png_infop info)
+{
+   /* This function is called when the whole image has been read,
+    * including any chunks after the image (up to and including
+    * the IEND).  You will usually have the same info chunk as you
+    * had in the header, although some data may have been added
+    * to the comments and time fields.
+    *
+    * Most people won't do much here, perhaps setting a flag that
+    * marks the image as finished.
+    */
+}
+
+/* Write a png file */
+void write_png(char *file_name /* , ... other image information ... */)
+{
+   FILE *fp;
+   png_structp png_ptr;
+   png_infop info_ptr;
+   png_colorp palette;
+
+   /* Open the file */
+   fp = fopen(file_name, "wb");
+   if (fp == NULL)
+      return (ERROR);
+
+   /* Create and initialize the png_struct with the desired error handler
+    * functions.  If you want to use the default stderr and longjump method,
+    * you can supply NULL for the last three parameters.  We also check that
+    * the library version is compatible with the one used at compile time,
+    * in case we are using dynamically linked libraries.  REQUIRED.
+    */
+   png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+       png_voidp user_error_ptr, user_error_fn, user_warning_fn);
+   if (png_ptr == NULL)
+   {
+      fclose(fp);
+      return (ERROR);
+   }
+
+   /* Allocate/initialize the image information data.  REQUIRED. */
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+   {
+      fclose(fp);
+      png_destroy_write_struct(&png_ptr,  NULL);
+      return (ERROR);
+   }
+
+   /* Set up error handling.  REQUIRED if you aren't supplying your own
+    * error handling functions in the png_create_write_struct() call.
+    */
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      /* If we get here, we had a problem writing the file. */
+      fclose(fp);
+      png_destroy_write_struct(&png_ptr, &info_ptr);
+      return (ERROR);
+   }
+
+   /* One of the following I/O initialization functions is REQUIRED. */
+
+#ifdef streams /* I/O initialization method 1 */
+   /* Set up the output control if you are using standard C streams. */
+   png_init_io(png_ptr, fp);
+
+#else no_streams /* I/O initialization method 2 */
+   /* If you are using replacement write functions, instead of calling
+    * png_init_io(), you would call:
+    */
+   png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
+       user_IO_flush_function);
+   /* where user_io_ptr is a structure you want available to the callbacks. */
+#endif no_streams /* Only use one initialization method */
+
+#ifdef hilevel
+   /* This is the easy way.  Use it if you already have all the
+    * image info living in the structure.  You could "|" many
+    * PNG_TRANSFORM flags into the png_transforms integer here.
+    */
+   png_write_png(png_ptr, info_ptr, png_transforms, NULL);
+
+#else
+   /* This is the hard way. */
+
+   /* Set the image information here.  Width and height are up to 2^31,
+    * bit_depth is one of 1, 2, 4, 8 or 16, but valid values also depend on
+    * the color_type selected.  color_type is one of PNG_COLOR_TYPE_GRAY,
+    * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB,
+    * or PNG_COLOR_TYPE_RGB_ALPHA.  interlace is either PNG_INTERLACE_NONE or
+    * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST
+    * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE.
+    * REQUIRED.
+    */
+   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
+       PNG_COLOR_TYPE_???, PNG_INTERLACE_????,
+       PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+   /* Set the palette if there is one.  REQUIRED for indexed-color images. */
+   palette = (png_colorp)png_malloc(png_ptr,
+       PNG_MAX_PALETTE_LENGTH * (sizeof (png_color)));
+   /* ... Set palette colors ... */
+   png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH);
+   /* You must not free palette here, because png_set_PLTE only makes a link
+    * to the palette that you allocated.  Wait until you are about to destroy
+    * the png structure.
+    */
+
+   /* Optional significant bit (sBIT) chunk. */
+   png_color_8 sig_bit;
+
+   /* If we are dealing with a grayscale image then */
+   sig_bit.gray = true_bit_depth;
+
+   /* Otherwise, if we are dealing with a color image then */
+   sig_bit.red = true_red_bit_depth;
+   sig_bit.green = true_green_bit_depth;
+   sig_bit.blue = true_blue_bit_depth;
+
+   /* If the image has an alpha channel then */
+   sig_bit.alpha = true_alpha_bit_depth;
+
+   png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+   /* Optional gamma chunk is strongly suggested if you have any guess
+    * as to the correct gamma of the image.
+    */
+   png_set_gAMA(png_ptr, info_ptr, gamma);
+
+   /* Optionally write comments into the image. */
+   {
+      png_text text_ptr[3];
+
+      char key0[] = "Title";
+      char text0[] = "Mona Lisa";
+      text_ptr[0].key = key0;
+      text_ptr[0].text = text0;
+      text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
+      text_ptr[0].itxt_length = 0;
+      text_ptr[0].lang = NULL;
+      text_ptr[0].lang_key = NULL;
+
+      char key1[] = "Author";
+      char text1[] = "Leonardo DaVinci";
+      text_ptr[1].key = key1;
+      text_ptr[1].text = text1;
+      text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
+      text_ptr[1].itxt_length = 0;
+      text_ptr[1].lang = NULL;
+      text_ptr[1].lang_key = NULL;
+
+      char key2[] = "Description";
+      char text2[] = "<long text>";
+      text_ptr[2].key = key2;
+      text_ptr[2].text = text2;
+      text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
+      text_ptr[2].itxt_length = 0;
+      text_ptr[2].lang = NULL;
+      text_ptr[2].lang_key = NULL;
+
+      png_set_text(write_ptr, write_info_ptr, text_ptr, 3);
+   }
+
+   /* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs. */
+
+   /* Note that if sRGB is present, the gAMA and cHRM chunks must be ignored
+    * on read and, if your application chooses to write them, they must
+    * be written in accordance with the sRGB profile.
+    */
+
+   /* Write the file header information.  REQUIRED. */
+   png_write_info(png_ptr, info_ptr);
+
+   /* If you want, you can write the info in two steps, in case you need to
+    * write your private chunk ahead of PLTE:
+    *
+    *   png_write_info_before_PLTE(write_ptr, write_info_ptr);
+    *   write_my_chunk();
+    *   png_write_info(png_ptr, info_ptr);
+    *
+    * However, given the level of known- and unknown-chunk support in 1.2.0
+    * and up, this should no longer be necessary.
+    */
+
+   /* Once we write out the header, the compression type on the text
+    * chunk gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
+    * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
+    * at the end.
+    */
+
+   /* Set up the transformations you want.  Note that these are
+    * all optional.  Only call them if you want them.
+    */
+
+   /* Invert monochrome pixels. */
+   png_set_invert_mono(png_ptr);
+
+   /* Shift the pixels up to a legal bit depth and fill in
+    * as appropriate to correctly scale the image.
+    */
+   png_set_shift(png_ptr, &sig_bit);
+
+   /* Pack pixels into bytes. */
+   png_set_packing(png_ptr);
+
+   /* Swap location of alpha bytes from ARGB to RGBA. */
+   png_set_swap_alpha(png_ptr);
+
+   /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
+    * RGB (4 channels -> 3 channels).  The second parameter is not used.
+    */
+   png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+   /* Flip BGR pixels to RGB. */
+   png_set_bgr(png_ptr);
+
+   /* Swap bytes of 16-bit files to most significant byte first. */
+   png_set_swap(png_ptr);
+
+   /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats. */
+   png_set_packswap(png_ptr);
+
+   /* Turn on interlace handling if you are not using png_write_image(). */
+   if (interlacing != 0)
+      number_passes = png_set_interlace_handling(png_ptr);
+   else
+      number_passes = 1;
+
+   /* The easiest way to write the image (you may have a different memory
+    * layout, however, so choose what fits your needs best).  You need to
+    * use the first method if you aren't handling interlacing yourself.
+    */
+   png_uint_32 k, height, width;
+
+   /* In this example, "image" is a one-dimensional array of bytes. */
+
+   /* Guard against integer overflow. */
+   if (height > PNG_SIZE_MAX / (width * bytes_per_pixel))
+      png_error(png_ptr, "Image data buffer would be too large");
+
+   png_byte image[height * width * bytes_per_pixel];
+   png_bytep row_pointers[height];
+
+   if (height > PNG_UINT_32_MAX / (sizeof (png_bytep)))
+      png_error(png_ptr, "Image is too tall to process in memory");
+
+   /* Set up pointers into your "image" byte array. */
+   for (k = 0; k < height; k++)
+      row_pointers[k] = image + k * width * bytes_per_pixel;
+
+   /* One of the following output methods is REQUIRED. */
+
+#ifdef entire /* Write out the entire image data in one call */
+   png_write_image(png_ptr, row_pointers);
+
+   /* The other way to write the image - deal with interlacing. */
+
+#else no_entire /* Write out the image data by one or more scanlines */
+
+   /* The number of passes is either 1 for non-interlaced images,
+    * or 7 for interlaced images.
+    */
+   for (pass = 0; pass < number_passes; pass++)
+   {
+      /* Write a few rows at a time. */
+      png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows);
+
+      /* If you are only writing one row at a time, this works. */
+      for (y = 0; y < height; y++)
+         png_write_rows(png_ptr, &row_pointers[y], 1);
+   }
+#endif no_entire /* Use only one output method */
+
+   /* You can write optional chunks like tEXt, zTXt, and tIME at the end
+    * as well.  Shouldn't be necessary in 1.2.0 and up, as all the public
+    * chunks are supported, and you can use png_set_unknown_chunks() to
+    * register unknown chunks into the info structure to be written out.
+    */
+
+   /* It is REQUIRED to call this to finish writing the rest of the file. */
+   png_write_end(png_ptr, info_ptr);
+#endif hilevel
+
+   /* If you png_malloced a palette, free it here.
+    * (Don't free info_ptr->palette, as shown in versions 1.0.5m and earlier of
+    * this example; if libpng mallocs info_ptr->palette, libpng will free it).
+    * If you allocated it with malloc() instead of png_malloc(), use free()
+    * instead of png_free().
+    */
+   png_free(png_ptr, palette);
+   palette = NULL;
+
+   /* Similarly, if you png_malloced any data that you passed in with
+    * png_set_something(), such as a hist or trans array, free it here,
+    * when you can be sure that libpng is through with it.
+    */
+   png_free(png_ptr, trans);
+   trans = NULL;
+
+   /* Whenever you use png_free(), it is a good idea to set the pointer to
+    * NULL in case your application inadvertently tries to png_free() it
+    * again.  When png_free() sees a NULL it returns without action, avoiding
+    * the double-free problem.
+    */
+
+   /* Clean up after the write, and free any allocated memory. */
+   png_destroy_write_struct(&png_ptr, &info_ptr);
+
+   /* Close the file. */
+   fclose(fp);
+
+   /* That's it! */
+   return (OK);
+}
+
+#endif /* if 0 */
diff --git a/extern/libpng/install-sh b/extern/libpng/install-sh
new file mode 100755
index 0000000000..8175c640fe
--- /dev/null
+++ b/extern/libpng/install-sh
@@ -0,0 +1,518 @@
+#!/bin/sh
+# install - install a program, script, or datafile
+
+scriptversion=2018-03-11.20; # UTC
+
+# This originates from X11R5 (mit/util/scripts/install.sh), which was
+# later released in X11R6 (xc/config/util/install.sh) with the
+# following copyright and license.
+#
+# Copyright (C) 1994 X Consortium
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to
+# deal in the Software without restriction, including without limitation the
+# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+# sell copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+# X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+# AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNEC-
+# TION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+# Except as contained in this notice, the name of the X Consortium shall not
+# be used in advertising or otherwise to promote the sale, use or other deal-
+# ings in this Software without prior written authorization from the X Consor-
+# tium.
+#
+#
+# FSF changes to this file are in the public domain.
+#
+# Calling this script install-sh is preferred over install.sh, to prevent
+# 'make' implicit rules from creating a file called install from it
+# when there is no Makefile.
+#
+# This script is compatible with the BSD install script, but was written
+# from scratch.
+
+tab='	'
+nl='
+'
+IFS=" $tab$nl"
+
+# Set DOITPROG to "echo" to test this script.
+
+doit=${DOITPROG-}
+doit_exec=${doit:-exec}
+
+# Put in absolute file names if you don't have them in your path;
+# or use environment vars.
+
+chgrpprog=${CHGRPPROG-chgrp}
+chmodprog=${CHMODPROG-chmod}
+chownprog=${CHOWNPROG-chown}
+cmpprog=${CMPPROG-cmp}
+cpprog=${CPPROG-cp}
+mkdirprog=${MKDIRPROG-mkdir}
+mvprog=${MVPROG-mv}
+rmprog=${RMPROG-rm}
+stripprog=${STRIPPROG-strip}
+
+posix_mkdir=
+
+# Desired mode of installed file.
+mode=0755
+
+chgrpcmd=
+chmodcmd=$chmodprog
+chowncmd=
+mvcmd=$mvprog
+rmcmd="$rmprog -f"
+stripcmd=
+
+src=
+dst=
+dir_arg=
+dst_arg=
+
+copy_on_change=false
+is_target_a_directory=possibly
+
+usage="\
+Usage: $0 [OPTION]... [-T] SRCFILE DSTFILE
+   or: $0 [OPTION]... SRCFILES... DIRECTORY
+   or: $0 [OPTION]... -t DIRECTORY SRCFILES...
+   or: $0 [OPTION]... -d DIRECTORIES...
+
+In the 1st form, copy SRCFILE to DSTFILE.
+In the 2nd and 3rd, copy all SRCFILES to DIRECTORY.
+In the 4th, create DIRECTORIES.
+
+Options:
+     --help     display this help and exit.
+     --version  display version info and exit.
+
+  -c            (ignored)
+  -C            install only if different (preserve the last data modification time)
+  -d            create directories instead of installing files.
+  -g GROUP      $chgrpprog installed files to GROUP.
+  -m MODE       $chmodprog installed files to MODE.
+  -o USER       $chownprog installed files to USER.
+  -s            $stripprog installed files.
+  -t DIRECTORY  install into DIRECTORY.
+  -T            report an error if DSTFILE is a directory.
+
+Environment variables override the default commands:
+  CHGRPPROG CHMODPROG CHOWNPROG CMPPROG CPPROG MKDIRPROG MVPROG
+  RMPROG STRIPPROG
+"
+
+while test $# -ne 0; do
+  case $1 in
+    -c) ;;
+
+    -C) copy_on_change=true;;
+
+    -d) dir_arg=true;;
+
+    -g) chgrpcmd="$chgrpprog $2"
+        shift;;
+
+    --help) echo "$usage"; exit $?;;
+
+    -m) mode=$2
+        case $mode in
+          *' '* | *"$tab"* | *"$nl"* | *'*'* | *'?'* | *'['*)
+            echo "$0: invalid mode: $mode" >&2
+            exit 1;;
+        esac
+        shift;;
+
+    -o) chowncmd="$chownprog $2"
+        shift;;
+
+    -s) stripcmd=$stripprog;;
+
+    -t)
+        is_target_a_directory=always
+        dst_arg=$2
+        # Protect names problematic for 'test' and other utilities.
+        case $dst_arg in
+          -* | [=\(\)!]) dst_arg=./$dst_arg;;
+        esac
+        shift;;
+
+    -T) is_target_a_directory=never;;
+
+    --version) echo "$0 $scriptversion"; exit $?;;
+
+    --) shift
+        break;;
+
+    -*) echo "$0: invalid option: $1" >&2
+        exit 1;;
+
+    *)  break;;
+  esac
+  shift
+done
+
+# We allow the use of options -d and -T together, by making -d
+# take the precedence; this is for compatibility with GNU install.
+
+if test -n "$dir_arg"; then
+  if test -n "$dst_arg"; then
+    echo "$0: target directory not allowed when installing a directory." >&2
+    exit 1
+  fi
+fi
+
+if test $# -ne 0 && test -z "$dir_arg$dst_arg"; then
+  # When -d is used, all remaining arguments are directories to create.
+  # When -t is used, the destination is already specified.
+  # Otherwise, the last argument is the destination.  Remove it from $@.
+  for arg
+  do
+    if test -n "$dst_arg"; then
+      # $@ is not empty: it contains at least $arg.
+      set fnord "$@" "$dst_arg"
+      shift # fnord
+    fi
+    shift # arg
+    dst_arg=$arg
+    # Protect names problematic for 'test' and other utilities.
+    case $dst_arg in
+      -* | [=\(\)!]) dst_arg=./$dst_arg;;
+    esac
+  done
+fi
+
+if test $# -eq 0; then
+  if test -z "$dir_arg"; then
+    echo "$0: no input file specified." >&2
+    exit 1
+  fi
+  # It's OK to call 'install-sh -d' without argument.
+  # This can happen when creating conditional directories.
+  exit 0
+fi
+
+if test -z "$dir_arg"; then
+  if test $# -gt 1 || test "$is_target_a_directory" = always; then
+    if test ! -d "$dst_arg"; then
+      echo "$0: $dst_arg: Is not a directory." >&2
+      exit 1
+    fi
+  fi
+fi
+
+if test -z "$dir_arg"; then
+  do_exit='(exit $ret); exit $ret'
+  trap "ret=129; $do_exit" 1
+  trap "ret=130; $do_exit" 2
+  trap "ret=141; $do_exit" 13
+  trap "ret=143; $do_exit" 15
+
+  # Set umask so as not to create temps with too-generous modes.
+  # However, 'strip' requires both read and write access to temps.
+  case $mode in
+    # Optimize common cases.
+    *644) cp_umask=133;;
+    *755) cp_umask=22;;
+
+    *[0-7])
+      if test -z "$stripcmd"; then
+        u_plus_rw=
+      else
+        u_plus_rw='% 200'
+      fi
+      cp_umask=`expr '(' 777 - $mode % 1000 ')' $u_plus_rw`;;
+    *)
+      if test -z "$stripcmd"; then
+        u_plus_rw=
+      else
+        u_plus_rw=,u+rw
+      fi
+      cp_umask=$mode$u_plus_rw;;
+  esac
+fi
+
+for src
+do
+  # Protect names problematic for 'test' and other utilities.
+  case $src in
+    -* | [=\(\)!]) src=./$src;;
+  esac
+
+  if test -n "$dir_arg"; then
+    dst=$src
+    dstdir=$dst
+    test -d "$dstdir"
+    dstdir_status=$?
+  else
+
+    # Waiting for this to be detected by the "$cpprog $src $dsttmp" command
+    # might cause directories to be created, which would be especially bad
+    # if $src (and thus $dsttmp) contains '*'.
+    if test ! -f "$src" && test ! -d "$src"; then
+      echo "$0: $src does not exist." >&2
+      exit 1
+    fi
+
+    if test -z "$dst_arg"; then
+      echo "$0: no destination specified." >&2
+      exit 1
+    fi
+    dst=$dst_arg
+
+    # If destination is a directory, append the input filename.
+    if test -d "$dst"; then
+      if test "$is_target_a_directory" = never; then
+        echo "$0: $dst_arg: Is a directory" >&2
+        exit 1
+      fi
+      dstdir=$dst
+      dstbase=`basename "$src"`
+      case $dst in
+	*/) dst=$dst$dstbase;;
+	*)  dst=$dst/$dstbase;;
+      esac
+      dstdir_status=0
+    else
+      dstdir=`dirname "$dst"`
+      test -d "$dstdir"
+      dstdir_status=$?
+    fi
+  fi
+
+  case $dstdir in
+    */) dstdirslash=$dstdir;;
+    *)  dstdirslash=$dstdir/;;
+  esac
+
+  obsolete_mkdir_used=false
+
+  if test $dstdir_status != 0; then
+    case $posix_mkdir in
+      '')
+        # Create intermediate dirs using mode 755 as modified by the umask.
+        # This is like FreeBSD 'install' as of 1997-10-28.
+        umask=`umask`
+        case $stripcmd.$umask in
+          # Optimize common cases.
+          *[2367][2367]) mkdir_umask=$umask;;
+          .*0[02][02] | .[02][02] | .[02]) mkdir_umask=22;;
+
+          *[0-7])
+            mkdir_umask=`expr $umask + 22 \
+              - $umask % 100 % 40 + $umask % 20 \
+              - $umask % 10 % 4 + $umask % 2
+            `;;
+          *) mkdir_umask=$umask,go-w;;
+        esac
+
+        # With -d, create the new directory with the user-specified mode.
+        # Otherwise, rely on $mkdir_umask.
+        if test -n "$dir_arg"; then
+          mkdir_mode=-m$mode
+        else
+          mkdir_mode=
+        fi
+
+        posix_mkdir=false
+        case $umask in
+          *[123567][0-7][0-7])
+            # POSIX mkdir -p sets u+wx bits regardless of umask, which
+            # is incompatible with FreeBSD 'install' when (umask & 300) != 0.
+            ;;
+          *)
+            # Note that $RANDOM variable is not portable (e.g. dash);  Use it
+            # here however when possible just to lower collision chance.
+            tmpdir=${TMPDIR-/tmp}/ins$RANDOM-$$
+
+            trap 'ret=$?; rmdir "$tmpdir/a/b" "$tmpdir/a" "$tmpdir" 2>/dev/null; exit $ret' 0
+
+            # Because "mkdir -p" follows existing symlinks and we likely work
+            # directly in world-writeable /tmp, make sure that the '$tmpdir'
+            # directory is successfully created first before we actually test
+            # 'mkdir -p' feature.
+            if (umask $mkdir_umask &&
+                $mkdirprog $mkdir_mode "$tmpdir" &&
+                exec $mkdirprog $mkdir_mode -p -- "$tmpdir/a/b") >/dev/null 2>&1
+            then
+              if test -z "$dir_arg" || {
+                   # Check for POSIX incompatibilities with -m.
+                   # HP-UX 11.23 and IRIX 6.5 mkdir -m -p sets group- or
+                   # other-writable bit of parent directory when it shouldn't.
+                   # FreeBSD 6.1 mkdir -m -p sets mode of existing directory.
+                   test_tmpdir="$tmpdir/a"
+                   ls_ld_tmpdir=`ls -ld "$test_tmpdir"`
+                   case $ls_ld_tmpdir in
+                     d????-?r-*) different_mode=700;;
+                     d????-?--*) different_mode=755;;
+                     *) false;;
+                   esac &&
+                   $mkdirprog -m$different_mode -p -- "$test_tmpdir" && {
+                     ls_ld_tmpdir_1=`ls -ld "$test_tmpdir"`
+                     test "$ls_ld_tmpdir" = "$ls_ld_tmpdir_1"
+                   }
+                 }
+              then posix_mkdir=:
+              fi
+              rmdir "$tmpdir/a/b" "$tmpdir/a" "$tmpdir"
+            else
+              # Remove any dirs left behind by ancient mkdir implementations.
+              rmdir ./$mkdir_mode ./-p ./-- "$tmpdir" 2>/dev/null
+            fi
+            trap '' 0;;
+        esac;;
+    esac
+
+    if
+      $posix_mkdir && (
+        umask $mkdir_umask &&
+        $doit_exec $mkdirprog $mkdir_mode -p -- "$dstdir"
+      )
+    then :
+    else
+
+      # The umask is ridiculous, or mkdir does not conform to POSIX,
+      # or it failed possibly due to a race condition.  Create the
+      # directory the slow way, step by step, checking for races as we go.
+
+      case $dstdir in
+        /*) prefix='/';;
+        [-=\(\)!]*) prefix='./';;
+        *)  prefix='';;
+      esac
+
+      oIFS=$IFS
+      IFS=/
+      set -f
+      set fnord $dstdir
+      shift
+      set +f
+      IFS=$oIFS
+
+      prefixes=
+
+      for d
+      do
+        test X"$d" = X && continue
+
+        prefix=$prefix$d
+        if test -d "$prefix"; then
+          prefixes=
+        else
+          if $posix_mkdir; then
+            (umask=$mkdir_umask &&
+             $doit_exec $mkdirprog $mkdir_mode -p -- "$dstdir") && break
+            # Don't fail if two instances are running concurrently.
+            test -d "$prefix" || exit 1
+          else
+            case $prefix in
+              *\'*) qprefix=`echo "$prefix" | sed "s/'/'\\\\\\\\''/g"`;;
+              *) qprefix=$prefix;;
+            esac
+            prefixes="$prefixes '$qprefix'"
+          fi
+        fi
+        prefix=$prefix/
+      done
+
+      if test -n "$prefixes"; then
+        # Don't fail if two instances are running concurrently.
+        (umask $mkdir_umask &&
+         eval "\$doit_exec \$mkdirprog $prefixes") ||
+          test -d "$dstdir" || exit 1
+        obsolete_mkdir_used=true
+      fi
+    fi
+  fi
+
+  if test -n "$dir_arg"; then
+    { test -z "$chowncmd" || $doit $chowncmd "$dst"; } &&
+    { test -z "$chgrpcmd" || $doit $chgrpcmd "$dst"; } &&
+    { test "$obsolete_mkdir_used$chowncmd$chgrpcmd" = false ||
+      test -z "$chmodcmd" || $doit $chmodcmd $mode "$dst"; } || exit 1
+  else
+
+    # Make a couple of temp file names in the proper directory.
+    dsttmp=${dstdirslash}_inst.$$_
+    rmtmp=${dstdirslash}_rm.$$_
+
+    # Trap to clean up those temp files at exit.
+    trap 'ret=$?; rm -f "$dsttmp" "$rmtmp" && exit $ret' 0
+
+    # Copy the file name to the temp name.
+    (umask $cp_umask && $doit_exec $cpprog "$src" "$dsttmp") &&
+
+    # and set any options; do chmod last to preserve setuid bits.
+    #
+    # If any of these fail, we abort the whole thing.  If we want to
+    # ignore errors from any of these, just make sure not to ignore
+    # errors from the above "$doit $cpprog $src $dsttmp" command.
+    #
+    { test -z "$chowncmd" || $doit $chowncmd "$dsttmp"; } &&
+    { test -z "$chgrpcmd" || $doit $chgrpcmd "$dsttmp"; } &&
+    { test -z "$stripcmd" || $doit $stripcmd "$dsttmp"; } &&
+    { test -z "$chmodcmd" || $doit $chmodcmd $mode "$dsttmp"; } &&
+
+    # If -C, don't bother to copy if it wouldn't change the file.
+    if $copy_on_change &&
+       old=`LC_ALL=C ls -dlL "$dst"     2>/dev/null` &&
+       new=`LC_ALL=C ls -dlL "$dsttmp"  2>/dev/null` &&
+       set -f &&
+       set X $old && old=:$2:$4:$5:$6 &&
+       set X $new && new=:$2:$4:$5:$6 &&
+       set +f &&
+       test "$old" = "$new" &&
+       $cmpprog "$dst" "$dsttmp" >/dev/null 2>&1
+    then
+      rm -f "$dsttmp"
+    else
+      # Rename the file to the real destination.
+      $doit $mvcmd -f "$dsttmp" "$dst" 2>/dev/null ||
+
+      # The rename failed, perhaps because mv can't rename something else
+      # to itself, or perhaps because mv is so ancient that it does not
+      # support -f.
+      {
+        # Now remove or move aside any old file at destination location.
+        # We try this two ways since rm can't unlink itself on some
+        # systems and the destination file might be busy for other
+        # reasons.  In this case, the final cleanup might fail but the new
+        # file should still install successfully.
+        {
+          test ! -f "$dst" ||
+          $doit $rmcmd -f "$dst" 2>/dev/null ||
+          { $doit $mvcmd -f "$dst" "$rmtmp" 2>/dev/null &&
+            { $doit $rmcmd -f "$rmtmp" 2>/dev/null; :; }
+          } ||
+          { echo "$0: cannot unlink or rename $dst" >&2
+            (exit 1); exit 1
+          }
+        } &&
+
+        # Now rename the file to the real destination.
+        $doit $mvcmd "$dsttmp" "$dst"
+      }
+    fi || exit 1
+
+    trap '' 0
+  fi
+done
+
+# Local variables:
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
diff --git a/extern/libpng/intel/filter_sse2_intrinsics.c b/extern/libpng/intel/filter_sse2_intrinsics.c
new file mode 100644
index 0000000000..f52aaa800a
--- /dev/null
+++ b/extern/libpng/intel/filter_sse2_intrinsics.c
@@ -0,0 +1,391 @@
+
+/* filter_sse2_intrinsics.c - SSE2 optimized filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2016-2017 Glenn Randers-Pehrson
+ * Written by Mike Klein and Matt Sarett
+ * Derived from arm/filter_neon_intrinsics.c
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_INTEL_SSE_IMPLEMENTATION > 0
+
+#include <immintrin.h>
+
+/* Functions in this file look at most 3 pixels (a,b,c) to predict the 4th (d).
+ * They're positioned like this:
+ *    prev:  c b
+ *    row:   a d
+ * The Sub filter predicts d=a, Avg d=(a+b)/2, and Paeth predicts d to be
+ * whichever of a, b, or c is closest to p=a+b-c.
+ */
+
+static __m128i load4(const void* p) {
+   int tmp;
+   memcpy(&tmp, p, sizeof(tmp));
+   return _mm_cvtsi32_si128(tmp);
+}
+
+static void store4(void* p, __m128i v) {
+   int tmp = _mm_cvtsi128_si32(v);
+   memcpy(p, &tmp, sizeof(int));
+}
+
+static __m128i load3(const void* p) {
+   png_uint_32 tmp = 0;
+   memcpy(&tmp, p, 3);
+   return _mm_cvtsi32_si128(tmp);
+}
+
+static void store3(void* p, __m128i v) {
+   int tmp = _mm_cvtsi128_si32(v);
+   memcpy(p, &tmp, 3);
+}
+
+void png_read_filter_row_sub3_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* The Sub filter predicts each pixel as the previous pixel, a.
+    * There is no pixel to the left of the first pixel.  It's encoded directly.
+    * That works with our main loop if we just say that left pixel was zero.
+    */
+   size_t rb;
+
+   __m128i a, d = _mm_setzero_si128();
+
+   png_debug(1, "in png_read_filter_row_sub3_sse2");
+
+   rb = row_info->rowbytes;
+   while (rb >= 4) {
+      a = d; d = load4(row);
+      d = _mm_add_epi8(d, a);
+      store3(row, d);
+
+      row += 3;
+      rb  -= 3;
+   }
+   if (rb > 0) {
+      a = d; d = load3(row);
+      d = _mm_add_epi8(d, a);
+      store3(row, d);
+
+      row += 3;
+      rb  -= 3;
+   }
+   PNG_UNUSED(prev)
+}
+
+void png_read_filter_row_sub4_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* The Sub filter predicts each pixel as the previous pixel, a.
+    * There is no pixel to the left of the first pixel.  It's encoded directly.
+    * That works with our main loop if we just say that left pixel was zero.
+    */
+   size_t rb;
+
+   __m128i a, d = _mm_setzero_si128();
+
+   png_debug(1, "in png_read_filter_row_sub4_sse2");
+
+   rb = row_info->rowbytes+4;
+   while (rb > 4) {
+      a = d; d = load4(row);
+      d = _mm_add_epi8(d, a);
+      store4(row, d);
+
+      row += 4;
+      rb  -= 4;
+   }
+   PNG_UNUSED(prev)
+}
+
+void png_read_filter_row_avg3_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* The Avg filter predicts each pixel as the (truncated) average of a and b.
+    * There's no pixel to the left of the first pixel.  Luckily, it's
+    * predicted to be half of the pixel above it.  So again, this works
+    * perfectly with our loop if we make sure a starts at zero.
+    */
+
+   size_t rb;
+
+   const __m128i zero = _mm_setzero_si128();
+
+   __m128i    b;
+   __m128i a, d = zero;
+
+   png_debug(1, "in png_read_filter_row_avg3_sse2");
+   rb = row_info->rowbytes;
+   while (rb >= 4) {
+      __m128i avg;
+             b = load4(prev);
+      a = d; d = load4(row );
+
+      /* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
+      avg = _mm_avg_epu8(a,b);
+      /* ...but we can fix it up by subtracting off 1 if it rounded up. */
+      avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
+                                            _mm_set1_epi8(1)));
+      d = _mm_add_epi8(d, avg);
+      store3(row, d);
+
+      prev += 3;
+      row  += 3;
+      rb   -= 3;
+   }
+   if (rb > 0) {
+      __m128i avg;
+             b = load3(prev);
+      a = d; d = load3(row );
+
+      /* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
+      avg = _mm_avg_epu8(a,b);
+      /* ...but we can fix it up by subtracting off 1 if it rounded up. */
+      avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
+                                            _mm_set1_epi8(1)));
+
+      d = _mm_add_epi8(d, avg);
+      store3(row, d);
+
+      prev += 3;
+      row  += 3;
+      rb   -= 3;
+   }
+}
+
+void png_read_filter_row_avg4_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* The Avg filter predicts each pixel as the (truncated) average of a and b.
+    * There's no pixel to the left of the first pixel.  Luckily, it's
+    * predicted to be half of the pixel above it.  So again, this works
+    * perfectly with our loop if we make sure a starts at zero.
+    */
+   size_t rb;
+   const __m128i zero = _mm_setzero_si128();
+   __m128i    b;
+   __m128i a, d = zero;
+
+   png_debug(1, "in png_read_filter_row_avg4_sse2");
+
+   rb = row_info->rowbytes+4;
+   while (rb > 4) {
+      __m128i avg;
+             b = load4(prev);
+      a = d; d = load4(row );
+
+      /* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
+      avg = _mm_avg_epu8(a,b);
+      /* ...but we can fix it up by subtracting off 1 if it rounded up. */
+      avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
+                                            _mm_set1_epi8(1)));
+
+      d = _mm_add_epi8(d, avg);
+      store4(row, d);
+
+      prev += 4;
+      row  += 4;
+      rb   -= 4;
+   }
+}
+
+/* Returns |x| for 16-bit lanes. */
+static __m128i abs_i16(__m128i x) {
+#if PNG_INTEL_SSE_IMPLEMENTATION >= 2
+   return _mm_abs_epi16(x);
+#else
+   /* Read this all as, return x<0 ? -x : x.
+   * To negate two's complement, you flip all the bits then add 1.
+    */
+   __m128i is_negative = _mm_cmplt_epi16(x, _mm_setzero_si128());
+
+   /* Flip negative lanes. */
+   x = _mm_xor_si128(x, is_negative);
+
+   /* +1 to negative lanes, else +0. */
+   x = _mm_sub_epi16(x, is_negative);
+   return x;
+#endif
+}
+
+/* Bytewise c ? t : e. */
+static __m128i if_then_else(__m128i c, __m128i t, __m128i e) {
+#if PNG_INTEL_SSE_IMPLEMENTATION >= 3
+   return _mm_blendv_epi8(e,t,c);
+#else
+   return _mm_or_si128(_mm_and_si128(c, t), _mm_andnot_si128(c, e));
+#endif
+}
+
+void png_read_filter_row_paeth3_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* Paeth tries to predict pixel d using the pixel to the left of it, a,
+    * and two pixels from the previous row, b and c:
+    *   prev: c b
+    *   row:  a d
+    * The Paeth function predicts d to be whichever of a, b, or c is nearest to
+    * p=a+b-c.
+    *
+    * The first pixel has no left context, and so uses an Up filter, p = b.
+    * This works naturally with our main loop's p = a+b-c if we force a and c
+    * to zero.
+    * Here we zero b and d, which become c and a respectively at the start of
+    * the loop.
+    */
+   size_t rb;
+   const __m128i zero = _mm_setzero_si128();
+   __m128i c, b = zero,
+           a, d = zero;
+
+   png_debug(1, "in png_read_filter_row_paeth3_sse2");
+
+   rb = row_info->rowbytes;
+   while (rb >= 4) {
+      /* It's easiest to do this math (particularly, deal with pc) with 16-bit
+       * intermediates.
+       */
+      __m128i pa,pb,pc,smallest,nearest;
+      c = b; b = _mm_unpacklo_epi8(load4(prev), zero);
+      a = d; d = _mm_unpacklo_epi8(load4(row ), zero);
+
+      /* (p-a) == (a+b-c - a) == (b-c) */
+   
+      pa = _mm_sub_epi16(b,c);
+
+      /* (p-b) == (a+b-c - b) == (a-c) */
+      pb = _mm_sub_epi16(a,c);
+
+      /* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
+      pc = _mm_add_epi16(pa,pb);
+
+      pa = abs_i16(pa);  /* |p-a| */
+      pb = abs_i16(pb);  /* |p-b| */
+      pc = abs_i16(pc);  /* |p-c| */
+
+      smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
+
+      /* Paeth breaks ties favoring a over b over c. */
+      nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
+                 if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
+                                                             c));
+
+      /* Note `_epi8`: we need addition to wrap modulo 255. */
+      d = _mm_add_epi8(d, nearest);
+      store3(row, _mm_packus_epi16(d,d));
+
+      prev += 3;
+      row  += 3;
+      rb   -= 3;
+   }
+   if (rb > 0) {
+      /* It's easiest to do this math (particularly, deal with pc) with 16-bit
+       * intermediates.
+       */
+      __m128i pa,pb,pc,smallest,nearest;
+      c = b; b = _mm_unpacklo_epi8(load3(prev), zero);
+      a = d; d = _mm_unpacklo_epi8(load3(row ), zero);
+
+      /* (p-a) == (a+b-c - a) == (b-c) */
+      pa = _mm_sub_epi16(b,c);
+
+      /* (p-b) == (a+b-c - b) == (a-c) */
+      pb = _mm_sub_epi16(a,c);
+
+      /* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
+      pc = _mm_add_epi16(pa,pb);
+
+      pa = abs_i16(pa);  /* |p-a| */
+      pb = abs_i16(pb);  /* |p-b| */
+      pc = abs_i16(pc);  /* |p-c| */
+
+      smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
+
+      /* Paeth breaks ties favoring a over b over c. */
+      nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
+                         if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
+                                                                     c));
+
+      /* Note `_epi8`: we need addition to wrap modulo 255. */
+      d = _mm_add_epi8(d, nearest);
+      store3(row, _mm_packus_epi16(d,d));
+
+      prev += 3;
+      row  += 3;
+      rb   -= 3;
+   }
+}
+
+void png_read_filter_row_paeth4_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* Paeth tries to predict pixel d using the pixel to the left of it, a,
+    * and two pixels from the previous row, b and c:
+    *   prev: c b
+    *   row:  a d
+    * The Paeth function predicts d to be whichever of a, b, or c is nearest to
+    * p=a+b-c.
+    *
+    * The first pixel has no left context, and so uses an Up filter, p = b.
+    * This works naturally with our main loop's p = a+b-c if we force a and c
+    * to zero.
+    * Here we zero b and d, which become c and a respectively at the start of
+    * the loop.
+    */
+   size_t rb;
+   const __m128i zero = _mm_setzero_si128();
+   __m128i pa,pb,pc,smallest,nearest;
+   __m128i c, b = zero,
+           a, d = zero;
+
+   png_debug(1, "in png_read_filter_row_paeth4_sse2");
+
+   rb = row_info->rowbytes+4;
+   while (rb > 4) {
+      /* It's easiest to do this math (particularly, deal with pc) with 16-bit
+       * intermediates.
+       */
+      c = b; b = _mm_unpacklo_epi8(load4(prev), zero);
+      a = d; d = _mm_unpacklo_epi8(load4(row ), zero);
+
+      /* (p-a) == (a+b-c - a) == (b-c) */
+      pa = _mm_sub_epi16(b,c);
+
+      /* (p-b) == (a+b-c - b) == (a-c) */
+      pb = _mm_sub_epi16(a,c);
+
+      /* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
+      pc = _mm_add_epi16(pa,pb);
+
+      pa = abs_i16(pa);  /* |p-a| */
+      pb = abs_i16(pb);  /* |p-b| */
+      pc = abs_i16(pc);  /* |p-c| */
+
+      smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
+
+      /* Paeth breaks ties favoring a over b over c. */
+      nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
+                         if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
+                                                                     c));
+
+      /* Note `_epi8`: we need addition to wrap modulo 255. */
+      d = _mm_add_epi8(d, nearest);
+      store4(row, _mm_packus_epi16(d,d));
+
+      prev += 4;
+      row  += 4;
+      rb   -= 4;
+   }
+}
+
+#endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */
+#endif /* READ */
diff --git a/extern/libpng/intel/intel_init.c b/extern/libpng/intel/intel_init.c
new file mode 100644
index 0000000000..2f8168b7c4
--- /dev/null
+++ b/extern/libpng/intel/intel_init.c
@@ -0,0 +1,52 @@
+
+/* intel_init.c - SSE2 optimized filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2016-2017 Glenn Randers-Pehrson
+ * Written by Mike Klein and Matt Sarett, Google, Inc.
+ * Derived from arm/arm_init.c
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+#if PNG_INTEL_SSE_IMPLEMENTATION > 0
+
+void
+png_init_filter_functions_sse2(png_structp pp, unsigned int bpp)
+{
+   /* The techniques used to implement each of these filters in SSE operate on
+    * one pixel at a time.
+    * So they generally speed up 3bpp images about 3x, 4bpp images about 4x.
+    * They can scale up to 6 and 8 bpp images and down to 2 bpp images,
+    * but they'd not likely have any benefit for 1bpp images.
+    * Most of these can be implemented using only MMX and 64-bit registers,
+    * but they end up a bit slower than using the equally-ubiquitous SSE2.
+   */
+   png_debug(1, "in png_init_filter_functions_sse2");
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth3_sse2;
+   }
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+          png_read_filter_row_paeth4_sse2;
+   }
+
+   /* No need optimize PNG_FILTER_VALUE_UP.  The compiler should
+    * autovectorize.
+    */
+}
+
+#endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */
+#endif /* PNG_READ_SUPPORTED */
diff --git a/extern/libpng/libpng-config.in b/extern/libpng/libpng-config.in
new file mode 100644
index 0000000000..69bf8e33f0
--- /dev/null
+++ b/extern/libpng/libpng-config.in
@@ -0,0 +1,127 @@
+#! /bin/sh
+
+# libpng-config
+# provides configuration info for libpng.
+
+# Copyright (C) 2002, 2004, 2006, 2007 Glenn Randers-Pehrson
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Modeled after libxml-config.
+
+version="@PNGLIB_VERSION@"
+prefix="@prefix@"
+exec_prefix="@exec_prefix@"
+libdir="@libdir@"
+includedir="@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
+libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
+all_libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ @LIBS@"
+I_opts="-I${includedir}"
+L_opts="-L${libdir}"
+R_opts=""
+cppflags=""
+ccopts=""
+ldopts=""
+
+usage()
+{
+    cat <<EOF
+Usage: $0 [OPTION] ...
+
+Known values for OPTION are:
+
+  --prefix        print libpng prefix
+  --libdir        print path to directory containing library
+  --libs          print library linking information
+  --ccopts        print compiler options
+  --cppflags      print pre-processor flags
+  --cflags        print preprocessor flags, I_opts, and compiler options
+  --I_opts        print "-I" include options
+  --L_opts        print linker "-L" flags for dynamic linking
+  --R_opts        print dynamic linker "-R" or "-rpath" flags
+  --ldopts        print linker options
+  --ldflags       print linker flags (ldopts, L_opts, R_opts, and libs)
+  --static        revise subsequent outputs for static linking
+  --help          print this help and exit
+  --version       print version information
+EOF
+
+    exit $1
+}
+
+if test $# -eq 0; then
+    usage 1
+fi
+
+while test $# -gt 0; do
+    case "$1" in
+
+    --prefix)
+        echo ${prefix}
+        ;;
+
+    --version)
+        echo ${version}
+        exit 0
+        ;;
+
+    --help)
+        usage 0
+        ;;
+
+    --ccopts)
+        echo ${ccopts}
+        ;;
+
+    --cppflags)
+        echo ${cppflags}
+        ;;
+
+    --cflags)
+        echo ${I_opts} ${cppflags} ${ccopts}
+        ;;
+
+    --libdir)
+        echo ${libdir}
+        ;;
+
+    --libs)
+        echo ${libs}
+        ;;
+
+    --I_opts)
+        echo ${I_opts}
+        ;;
+
+    --L_opts)
+        echo ${L_opts}
+        ;;
+
+    --R_opts)
+        echo ${R_opts}
+        ;;
+
+    --ldopts)
+        echo ${ldopts}
+        ;;
+
+    --ldflags)
+        echo ${ldopts} ${L_opts} ${R_opts} ${libs}
+        ;;
+
+    --static)
+        R_opts=""
+        libs=${all_libs}
+        ;;
+
+    *)
+        usage
+        exit 1
+        ;;
+    esac
+    shift
+done
+
+exit 0
diff --git a/extern/libpng/libpng-manual.txt b/extern/libpng/libpng-manual.txt
new file mode 100644
index 0000000000..5dad92fbf7
--- /dev/null
+++ b/extern/libpng/libpng-manual.txt
@@ -0,0 +1,5409 @@
+libpng-manual.txt - A description on how to use and modify libpng
+
+ Copyright (c) 2018-2019 Cosmin Truta
+ Copyright (c) 1998-2018 Glenn Randers-Pehrson
+
+ This document is released under the libpng license.
+ For conditions of distribution and use, see the disclaimer
+ and license in png.h
+
+ Based on:
+
+ libpng version 1.6.36, December 2018, through 1.6.37 - April 2019
+ Updated and distributed by Cosmin Truta
+ Copyright (c) 2018-2019 Cosmin Truta
+
+ libpng versions 0.97, January 1998, through 1.6.35 - July 2018
+ Updated and distributed by Glenn Randers-Pehrson
+ Copyright (c) 1998-2018 Glenn Randers-Pehrson
+
+ libpng 1.0 beta 6 - version 0.96 - May 28, 1997
+ Updated and distributed by Andreas Dilger
+ Copyright (c) 1996, 1997 Andreas Dilger
+
+ libpng 1.0 beta 2 - version 0.88 - January 26, 1996
+ For conditions of distribution and use, see copyright
+ notice in png.h. Copyright (c) 1995, 1996 Guy Eric
+ Schalnat, Group 42, Inc.
+
+ Updated/rewritten per request in the libpng FAQ
+ Copyright (c) 1995, 1996 Frank J. T. Wojcik
+ December 18, 1995 & January 20, 1996
+
+ TABLE OF CONTENTS
+
+    I. Introduction
+   II. Structures
+  III. Reading
+   IV. Writing
+    V. Simplified API
+   VI. Modifying/Customizing libpng
+  VII. MNG support
+ VIII. Changes to Libpng from version 0.88
+   IX. Changes to Libpng from version 1.0.x to 1.2.x
+    X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+   XI. Changes to Libpng from version 1.4.x to 1.5.x
+  XII. Changes to Libpng from version 1.5.x to 1.6.x
+ XIII. Detecting libpng
+  XIV. Source code repository
+   XV. Coding style
+
+I. Introduction
+
+This file describes how to use and modify the PNG reference library
+(known as libpng) for your own use.  In addition to this
+file, example.c is a good starting point for using the library, as
+it is heavily commented and should include everything most people
+will need.  We assume that libpng is already installed; see the
+INSTALL file for instructions on how to configure and install libpng.
+
+For examples of libpng usage, see the files "example.c", "pngtest.c",
+and the files in the "contrib" directory, all of which are included in
+the libpng distribution.
+
+Libpng was written as a companion to the PNG specification, as a way
+of reducing the amount of time and effort it takes to support the PNG
+file format in application programs.
+
+The PNG specification (second edition), November 2003, is available as
+a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
+<https://www.w3.org/TR/2003/REC-PNG-20031110/>.
+The W3C and ISO documents have identical technical content.
+
+The PNG-1.2 specification is available at
+<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
+It is technically equivalent
+to the PNG specification (second edition) but has some additional material.
+
+The PNG-1.0 specification is available as RFC 2083 at
+<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
+W3C Recommendation at <https://www.w3.org/TR/REC-png-961001>.
+
+Some additional chunks are described in the special-purpose public chunks
+documents at <http://www.libpng.org/pub/png/spec/register/>
+
+Other information
+about PNG, and the latest version of libpng, can be found at the PNG home
+page, <http://www.libpng.org/pub/png/>.
+
+Most users will not have to modify the library significantly; advanced
+users may want to modify it more.  All attempts were made to make it as
+complete as possible, while keeping the code easy to understand.
+Currently, this library only supports C.  Support for other languages
+is being considered.
+
+Libpng has been designed to handle multiple sessions at one time,
+to be easily modifiable, to be portable to the vast majority of
+machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
+to use.  The ultimate goal of libpng is to promote the acceptance of
+the PNG file format in whatever way possible.  While there is still
+work to be done (see the TODO file), libpng should cover the
+majority of the needs of its users.
+
+Libpng uses zlib for its compression and decompression of PNG files.
+Further information about zlib, and the latest version of zlib, can
+be found at the zlib home page, <https://zlib.net/>.
+The zlib compression utility is a general purpose utility that is
+useful for more than PNG files, and can be used without libpng.
+See the documentation delivered with zlib for more details.
+You can usually find the source files for the zlib utility wherever you
+find the libpng source files.
+
+Libpng is thread safe, provided the threads are using different
+instances of the structures.  Each thread should have its own
+png_struct and png_info instances, and thus its own image.
+Libpng does not protect itself against two threads using the
+same instance of a structure.
+
+II. Structures
+
+There are two main structures that are important to libpng, png_struct
+and png_info.  Both are internal structures that are no longer exposed
+in the libpng interface (as of libpng 1.5.0).
+
+The png_info structure is designed to provide information about the
+PNG file.  At one time, the fields of png_info were intended to be
+directly accessible to the user.  However, this tended to cause problems
+with applications using dynamically loaded libraries, and as a result
+a set of interface functions for png_info (the png_get_*() and png_set_*()
+functions) was developed, and direct access to the png_info fields was
+deprecated..
+
+The png_struct structure is the object used by the library to decode a
+single image.  As of 1.5.0 this structure is also not exposed.
+
+Almost all libpng APIs require a pointer to a png_struct as the first argument.
+Many (in particular the png_set and png_get APIs) also require a pointer
+to png_info as the second argument.  Some application visible macros
+defined in png.h designed for basic data access (reading and writing
+integers in the PNG format) don't take a png_info pointer, but it's almost
+always safe to assume that a (png_struct*) has to be passed to call an API
+function.
+
+You can have more than one png_info structure associated with an image,
+as illustrated in pngtest.c, one for information valid prior to the
+IDAT chunks and another (called "end_info" below) for things after them.
+
+The png.h header file is an invaluable reference for programming with libpng.
+And while I'm on the topic, make sure you include the libpng header file:
+
+#include <png.h>
+
+and also (as of libpng-1.5.0) the zlib header file, if you need it:
+
+#include <zlib.h>
+
+Types
+
+The png.h header file defines a number of integral types used by the
+APIs.  Most of these are fairly obvious; for example types corresponding
+to integers of particular sizes and types for passing color values.
+
+One exception is how non-integral numbers are handled.  For application
+convenience most APIs that take such numbers have C (double) arguments;
+however, internally PNG, and libpng, use 32 bit signed integers and encode
+the value by multiplying by 100,000.  As of libpng 1.5.0 a convenience
+macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
+which is simply (png_int_32).
+
+All APIs that take (double) arguments also have a matching API that
+takes the corresponding fixed point integer arguments.  The fixed point
+API has the same name as the floating point one with "_fixed" appended.
+The actual range of values permitted in the APIs is frequently less than
+the full range of (png_fixed_point) (-21474 to +21474).  When APIs require
+a non-negative argument the type is recorded as png_uint_32 above.  Consult
+the header file and the text below for more information.
+
+Special care must be take with sCAL chunk handling because the chunk itself
+uses non-integral values encoded as strings containing decimal floating point
+numbers.  See the comments in the header file.
+
+Configuration
+
+The main header file function declarations are frequently protected by C
+preprocessing directives of the form:
+
+    #ifdef PNG_feature_SUPPORTED
+    declare-function
+    #endif
+    ...
+    #ifdef PNG_feature_SUPPORTED
+    use-function
+    #endif
+
+The library can be built without support for these APIs, although a
+standard build will have all implemented APIs.  Application programs
+should check the feature macros before using an API for maximum
+portability.  From libpng 1.5.0 the feature macros set during the build
+of libpng are recorded in the header file "pnglibconf.h" and this file
+is always included by png.h.
+
+If you don't need to change the library configuration from the default, skip to
+the next section ("Reading").
+
+Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
+of the build project files in the 'projects' directory simply copy
+scripts/pnglibconf.h.prebuilt to pnglibconf.h.  This means that these build
+systems do not permit easy auto-configuration of the library - they only
+support the default configuration.
+
+The easiest way to make minor changes to the libpng configuration when
+auto-configuration is supported is to add definitions to the command line
+using (typically) CPPFLAGS.  For example:
+
+CPPFLAGS=-DPNG_NO_FLOATING_ARITHMETIC
+
+will change the internal libpng math implementation for gamma correction and
+other arithmetic calculations to fixed point, avoiding the need for fast
+floating point support.  The result can be seen in the generated pnglibconf.h -
+make sure it contains the changed feature macro setting.
+
+If you need to make more extensive configuration changes - more than one or two
+feature macro settings - you can either add -DPNG_USER_CONFIG to the build
+command line and put a list of feature macro settings in pngusr.h or you can set
+DFA_XTRA (a makefile variable) to a file containing the same information in the
+form of 'option' settings.
+
+A. Changing pnglibconf.h
+
+A variety of methods exist to build libpng.  Not all of these support
+reconfiguration of pnglibconf.h.  To reconfigure pnglibconf.h it must either be
+rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
+
+Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to
+pnglibconf.h and changing the lines defining the supported features, paying
+very close attention to the 'option' information in scripts/pnglibconf.dfa
+that describes those features and their requirements.  This is easy to get
+wrong.
+
+B. Configuration using DFA_XTRA
+
+Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
+variant such as 'nawk' or 'gawk', is available.  The configure build will
+automatically find an appropriate awk and build pnglibconf.h.
+The scripts/pnglibconf.mak file contains a set of make rules for doing the
+same thing if configure is not used, and many of the makefiles in the scripts
+directory use this approach.
+
+When rebuilding simply write a new file containing changed options and set
+DFA_XTRA to the name of this file.  This causes the build to append the new file
+to the end of scripts/pnglibconf.dfa.  The pngusr.dfa file should contain lines
+of the following forms:
+
+everything = off
+
+This turns all optional features off.  Include it at the start of pngusr.dfa to
+make it easier to build a minimal configuration.  You will need to turn at least
+some features on afterward to enable either reading or writing code, or both.
+
+option feature on
+option feature off
+
+Enable or disable a single feature.  This will automatically enable other
+features required by a feature that is turned on or disable other features that
+require a feature which is turned off.  Conflicting settings will cause an error
+message to be emitted by awk.
+
+setting feature default value
+
+Changes the default value of setting 'feature' to 'value'.  There are a small
+number of settings listed at the top of pnglibconf.h, they are documented in the
+source code.  Most of these values have performance implications for the library
+but most of them have no visible effect on the API.  Some can also be overridden
+from the API.
+
+This method of building a customized pnglibconf.h is illustrated in
+contrib/pngminim/*.  See the "$(PNGCONF):" target in the makefile and
+pngusr.dfa in these directories.
+
+C. Configuration using PNG_USER_CONFIG
+
+If -DPNG_USER_CONFIG is added to the CPPFLAGS when pnglibconf.h is built,
+the file pngusr.h will automatically be included before the options in
+scripts/pnglibconf.dfa are processed.  Your pngusr.h file should contain only
+macro definitions turning features on or off or setting settings.
+
+Apart from the global setting "everything = off" all the options listed above
+can be set using macros in pngusr.h:
+
+#define PNG_feature_SUPPORTED
+
+is equivalent to:
+
+option feature on
+
+#define PNG_NO_feature
+
+is equivalent to:
+
+option feature off
+
+#define PNG_feature value
+
+is equivalent to:
+
+setting feature default value
+
+Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
+pngusr file you supply override the contents of scripts/pnglibconf.dfa
+
+If confusing or incomprehensible behavior results it is possible to
+examine the intermediate file pnglibconf.dfn to find the full set of
+dependency information for each setting and option.  Simply locate the
+feature in the file and read the C comments that precede it.
+
+This method is also illustrated in the contrib/pngminim/* makefiles and
+pngusr.h.
+
+III. Reading
+
+We'll now walk you through the possible functions to call when reading
+in a PNG file sequentially, briefly explaining the syntax and purpose
+of each one.  See example.c and png.h for more detail.  While
+progressive reading is covered in the next section, you will still
+need some of the functions discussed in this section to read a PNG
+file.
+
+Setup
+
+You will want to do the I/O initialization(*) before you get into libpng,
+so if it doesn't work, you don't have much to undo.  Of course, you
+will also want to insure that you are, in fact, dealing with a PNG
+file.  Libpng provides a simple check to see if a file is a PNG file.
+To use it, pass in the first 1 to 8 bytes of the file to the function
+png_sig_cmp(), and it will return 0 (false) if the bytes match the
+corresponding bytes of the PNG signature, or nonzero (true) otherwise.
+Of course, the more bytes you pass in, the greater the accuracy of the
+prediction.
+
+If you are intending to keep the file pointer open for use in libpng,
+you must ensure you don't read more than 8 bytes from the beginning
+of the file, and you also have to make a call to png_set_sig_bytes()
+with the number of bytes you read from the beginning.  Libpng will
+then only check the bytes (if any) that your program didn't read.
+
+(*): If you are not using the standard I/O functions, you will need
+to replace them with custom functions.  See the discussion under
+Customizing libpng.
+
+    FILE *fp = fopen(file_name, "rb");
+    if (!fp)
+    {
+       return ERROR;
+    }
+
+    if (fread(header, 1, number, fp) != number)
+    {
+       return ERROR;
+    }
+
+    is_png = !png_sig_cmp(header, 0, number);
+    if (!is_png)
+    {
+       return NOT_PNG;
+    }
+
+Next, png_struct and png_info need to be allocated and initialized.  In
+order to ensure that the size of these structures is correct even with a
+dynamically linked libpng, there are functions to initialize and
+allocate the structures.  We also pass the library version, optional
+pointers to error handling functions, and a pointer to a data struct for
+use by the error functions, if necessary (the pointer and functions can
+be NULL if the default error handlers are to be used).  See the section
+on Changes to Libpng below regarding the old initialization functions.
+The structure allocation functions quietly return NULL if they fail to
+create the structure, so your application should check for that.
+
+    png_structp png_ptr = png_create_read_struct
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+       return ERROR;
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+    {
+       png_destroy_read_struct(&png_ptr,
+           (png_infopp)NULL, (png_infopp)NULL);
+       return ERROR;
+    }
+
+If you want to use your own memory allocation routines,
+use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
+png_create_read_struct_2() instead of png_create_read_struct():
+
+    png_structp png_ptr = png_create_read_struct_2
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn, (png_voidp)
+        user_mem_ptr, user_malloc_fn, user_free_fn);
+
+The error handling routines passed to png_create_read_struct()
+and the memory alloc/free routines passed to png_create_struct_2()
+are only necessary if you are not using the libpng supplied error
+handling and memory alloc/free functions.
+
+When libpng encounters an error, it expects to longjmp back
+to your routine.  Therefore, you will need to call setjmp and pass
+your png_jmpbuf(png_ptr).  If you read the file from different
+routines, you will need to update the longjmp buffer every time you enter
+a new routine that will call a png_*() function.
+
+See your documentation of setjmp/longjmp for your compiler for more
+information on setjmp/longjmp.  See the discussion on libpng error
+handling in the Customizing Libpng section below for more information
+on the libpng error handling.  If an error occurs, and libpng longjmp's
+back to your setjmp, you will want to call png_destroy_read_struct() to
+free any memory.
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+           &end_info);
+       fclose(fp);
+       return ERROR;
+    }
+
+Pass (png_infopp)NULL instead of &end_info if you didn't create
+an end_info structure.
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Now you need to set up the input code.  The default for libpng is to
+use the C function fread().  If you use this, you will need to pass a
+valid FILE * in the function png_init_io().  Be sure that the file is
+opened in binary mode.  If you wish to handle reading data in another
+way, you need not call the png_init_io() function, but you must then
+implement the libpng I/O methods discussed in the Customizing Libpng
+section below.
+
+    png_init_io(png_ptr, fp);
+
+If you had previously opened the file and read any of the signature from
+the beginning in order to see if this was a PNG file, you need to let
+libpng know that there are some bytes missing from the start of the file.
+
+    png_set_sig_bytes(png_ptr, number);
+
+You can change the zlib compression buffer size to be used while
+reading compressed data with
+
+    png_set_compression_buffer_size(png_ptr, buffer_size);
+
+where the default size is 8192 bytes.  Note that the buffer size
+is changed immediately and the buffer is reallocated immediately,
+instead of setting a flag to be acted upon later.
+
+If you want CRC errors to be handled in a different manner than
+the default, use
+
+    png_set_crc_action(png_ptr, crit_action, ancil_action);
+
+The values for png_set_crc_action() say how libpng is to handle CRC errors in
+ancillary and critical chunks, and whether to use the data contained
+therein. Starting with libpng-1.6.26, this also governs how an ADLER32 error
+is handled while reading the IDAT chunk. Note that it is impossible to
+"discard" data in a critical chunk.
+
+Choices for (int) crit_action are
+   PNG_CRC_DEFAULT      0  error/quit
+   PNG_CRC_ERROR_QUIT   1  error/quit
+   PNG_CRC_WARN_USE     3  warn/use data
+   PNG_CRC_QUIET_USE    4  quiet/use data
+   PNG_CRC_NO_CHANGE    5  use the current value
+
+Choices for (int) ancil_action are
+   PNG_CRC_DEFAULT      0  error/quit
+   PNG_CRC_ERROR_QUIT   1  error/quit
+   PNG_CRC_WARN_DISCARD 2  warn/discard data
+   PNG_CRC_WARN_USE     3  warn/use data
+   PNG_CRC_QUIET_USE    4  quiet/use data
+   PNG_CRC_NO_CHANGE    5  use the current value
+
+When the setting for crit_action is PNG_CRC_QUIET_USE, the CRC and ADLER32
+checksums are not only ignored, but they are not evaluated.
+
+Setting up callback code
+
+You can set up a callback function to handle any unknown chunks in the
+input stream. You must supply the function
+
+    read_chunk_callback(png_structp png_ptr,
+         png_unknown_chunkp chunk);
+    {
+       /* The unknown chunk structure contains your
+          chunk data, along with similar data for any other
+          unknown chunks: */
+
+           png_byte name[5];
+           png_byte *data;
+           size_t size;
+
+       /* Note that libpng has already taken care of
+          the CRC handling */
+
+       /* put your code here.  Search for your chunk in the
+          unknown chunk structure, process it, and return one
+          of the following: */
+
+       return -n; /* chunk had an error */
+       return 0; /* did not recognize */
+       return n; /* success */
+    }
+
+(You can give your function another name that you like instead of
+"read_chunk_callback")
+
+To inform libpng about your function, use
+
+    png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
+        read_chunk_callback);
+
+This names not only the callback function, but also a user pointer that
+you can retrieve with
+
+    png_get_user_chunk_ptr(png_ptr);
+
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks which the callback does not handle will be saved when read.  You can
+cause them to be discarded by returning '1' ("handled") instead of '0'.  This
+behavior will change in libpng 1.7 and the default handling set by the
+png_set_keep_unknown_chunks() function, described below, will be used when the
+callback returns 0.  If you want the existing behavior you should set the global
+default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
+versions of libpng and with 1.7.  Libpng 1.6 issues a warning if you keep the
+default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.
+
+At this point, you can set up a callback function that will be
+called after each row has been read, which you can use to control
+a progress meter or the like.  It's demonstrated in pngtest.c.
+You must supply a function
+
+    void read_row_callback(png_structp png_ptr,
+       png_uint_32 row, int pass);
+    {
+      /* put your code here */
+    }
+
+(You can give it another name that you like instead of "read_row_callback")
+
+To inform libpng about your function, use
+
+    png_set_read_status_fn(png_ptr, read_row_callback);
+
+When this function is called the row has already been completely processed and
+the 'row' and 'pass' refer to the next row to be handled.  For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0.  For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes.  Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass-1'; if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+Unknown-chunk handling
+
+Now you get to set the way the library processes unknown chunks in the
+input PNG stream. Both known and unknown chunks will be read.  Normal
+behavior is that known chunks will be parsed into information in
+various info_ptr members while unknown chunks will be discarded. This
+behavior can be wasteful if your application will never use some known
+chunk types. To change this, you can call:
+
+    png_set_keep_unknown_chunks(png_ptr, keep,
+        chunk_list, num_chunks);
+
+    keep       - 0: default unknown chunk handling
+                 1: ignore; do not keep
+                 2: keep only if safe-to-copy
+                 3: keep even if unsafe-to-copy
+
+               You can use these definitions:
+                 PNG_HANDLE_CHUNK_AS_DEFAULT   0
+                 PNG_HANDLE_CHUNK_NEVER        1
+                 PNG_HANDLE_CHUNK_IF_SAFE      2
+                 PNG_HANDLE_CHUNK_ALWAYS       3
+
+    chunk_list - list of chunks affected (a byte string,
+                 five bytes per chunk, NULL or '\0' if
+                 num_chunks is positive; ignored if
+                 numchunks <= 0).
+
+    num_chunks - number of chunks affected; if 0, all
+                 unknown chunks are affected.  If positive,
+                 only the chunks in the list are affected,
+                 and if negative all unknown chunks and
+                 all known chunks except for the IHDR,
+                 PLTE, tRNS, IDAT, and IEND chunks are
+                 affected.
+
+Unknown chunks declared in this way will be saved as raw data onto a
+list of png_unknown_chunk structures.  If a chunk that is normally
+known to libpng is named in the list, it will be handled as unknown,
+according to the "keep" directive.  If a chunk is named in successive
+instances of png_set_keep_unknown_chunks(), the final instance will
+take precedence.  The IHDR and IEND chunks should not be named in
+chunk_list; if they are, libpng will process them normally anyway.
+If you know that your application will never make use of some particular
+chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below.
+
+Here is an example of the usage of png_set_keep_unknown_chunks(),
+where the private "vpAg" chunk will later be processed by a user chunk
+callback function:
+
+    png_byte vpAg[5]={118, 112,  65, 103, (png_byte) '\0'};
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      png_byte unused_chunks[]=
+      {
+        104,  73,  83,  84, (png_byte) '\0',   /* hIST */
+        105,  84,  88, 116, (png_byte) '\0',   /* iTXt */
+        112,  67,  65,  76, (png_byte) '\0',   /* pCAL */
+        115,  67,  65,  76, (png_byte) '\0',   /* sCAL */
+        115,  80,  76,  84, (png_byte) '\0',   /* sPLT */
+        116,  73,  77,  69, (png_byte) '\0',   /* tIME */
+      };
+    #endif
+
+    ...
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      /* ignore all unknown chunks
+       * (use global setting "2" for libpng16 and earlier):
+       */
+      png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);
+
+      /* except for vpAg: */
+      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
+
+      /* also ignore unused known chunks: */
+      png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
+         (int)(sizeof unused_chunks)/5);
+    #endif
+
+User limits
+
+The PNG specification allows the width and height of an image to be as
+large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
+For safety, libpng imposes a default limit of 1 million rows and columns.
+Larger images will be rejected immediately with a png_error() call. If
+you wish to change these limits, you can use
+
+   png_set_user_limits(png_ptr, width_max, height_max);
+
+to set your own limits (libpng may reject some very wide images
+anyway because of potential buffer overflow conditions).
+
+You should put this statement after you create the PNG structure and
+before calling png_read_info(), png_read_png(), or png_process_data().
+
+When writing a PNG datastream, put this statement before calling
+png_write_info() or png_write_png().
+
+If you need to retrieve the limits that are being applied, use
+
+   width_max = png_get_user_width_max(png_ptr);
+   height_max = png_get_user_height_max(png_ptr);
+
+The PNG specification sets no limit on the number of ancillary chunks
+allowed in a PNG datastream.  By default, libpng imposes a limit of
+a total of 1000 sPLT, tEXt, iTXt, zTXt, and unknown chunks to be stored.
+If you have set up both info_ptr and end_info_ptr, the limit applies
+separately to each.  You can change the limit on the total number of such
+chunks that will be stored, with
+
+   png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
+
+where 0x7fffffffL means unlimited.  You can retrieve this limit with
+
+   chunk_cache_max = png_get_chunk_cache_max(png_ptr);
+
+Libpng imposes a limit of 8 Megabytes (8,000,000 bytes) on the amount of
+memory that any chunk other than IDAT can occupy, originally or when
+decompressed (prior to libpng-1.6.32 the limit was only applied to compressed
+chunks after decompression). You can change this limit with
+
+   png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
+
+and you can retrieve the limit with
+
+   chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
+
+Any chunks that would cause either of these limits to be exceeded will
+be ignored.
+
+Information about your system
+
+If you intend to display the PNG or to incorporate it in other image data you
+need to tell libpng information about your display or drawing surface so that
+libpng can convert the values in the image to match the display.
+
+From libpng-1.5.4 this information can be set before reading the PNG file
+header.  In earlier versions png_set_gamma() existed but behaved incorrectly if
+called before the PNG file header had been read and png_set_alpha_mode() did not
+exist.
+
+If you need to support versions prior to libpng-1.5.4 test the version number
+as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures
+described in the appropriate manual page.
+
+You give libpng the encoding expected by your system expressed as a 'gamma'
+value.  You can also specify a default encoding for the PNG file in
+case the required information is missing from the file.  By default libpng
+assumes that the PNG data matches your system, to keep this default call:
+
+   png_set_gamma(png_ptr, screen_gamma, output_gamma);
+
+or you can use the fixed point equivalent:
+
+   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma,
+      PNG_FP_1*output_gamma);
+
+If you don't know the gamma for your system it is probably 2.2 - a good
+approximation to the IEC standard for display systems (sRGB).  If images are
+too contrasty or washed out you got the value wrong - check your system
+documentation!
+
+Many systems permit the system gamma to be changed via a lookup table in the
+display driver, a few systems, including older Macs, change the response by
+default.  As of 1.5.4 three special values are available to handle common
+situations:
+
+   PNG_DEFAULT_sRGB: Indicates that the system conforms to the
+                     IEC 61966-2-1 standard.  This matches almost
+                     all systems.
+   PNG_GAMMA_MAC_18: Indicates that the system is an older
+                     (pre Mac OS 10.6) Apple Macintosh system with
+                     the default settings.
+   PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates
+                     that the system expects data with no gamma
+                     encoding.
+
+You would use the linear (unencoded) value if you need to process the pixel
+values further because this avoids the need to decode and re-encode each
+component value whenever arithmetic is performed.  A lot of graphics software
+uses linear values for this reason, often with higher precision component values
+to preserve overall accuracy.
+
+
+The output_gamma value expresses how to decode the output values, not how
+they are encoded.  The values used correspond to the normal numbers used to
+describe the overall gamma of a computer display system; for example 2.2 for
+an sRGB conformant system.  The values are scaled by 100000 in the _fixed
+version of the API (so 220000 for sRGB.)
+
+The inverse of the value is always used to provide a default for the PNG file
+encoding if it has no gAMA chunk and if png_set_gamma() has not been called
+to override the PNG gamma information.
+
+When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
+opaque pixels however pixels with lower alpha values are not encoded,
+regardless of the output gamma setting.
+
+When the standard Porter Duff handling is requested with mode 1 the output
+encoding is set to be linear and the output_gamma value is only relevant
+as a default for input data that has no gamma information.  The linear output
+encoding will be overridden if png_set_gamma() is called - the results may be
+highly unexpected!
+
+The following numbers are derived from the sRGB standard and the research
+behind it.  sRGB is defined to be approximated by a PNG gAMA chunk value of
+0.45455 (1/2.2) for PNG.  The value implicitly includes any viewing
+correction required to take account of any differences in the color
+environment of the original scene and the intended display environment; the
+value expresses how to *decode* the image for display, not how the original
+data was *encoded*.
+
+sRGB provides a peg for the PNG standard by defining a viewing environment.
+sRGB itself, and earlier TV standards, actually use a more complex transform
+(a linear portion then a gamma 2.4 power law) than PNG can express.  (PNG is
+limited to simple power laws.)  By saying that an image for direct display on
+an sRGB conformant system should be stored with a gAMA chunk value of 45455
+(11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
+makes it possible to derive values for other display systems and
+environments.
+
+The Mac value is deduced from the sRGB based on an assumption that the actual
+extra viewing correction used in early Mac display systems was implemented as
+a power 1.45 lookup table.
+
+Any system where a programmable lookup table is used or where the behavior of
+the final display device characteristics can be changed requires system
+specific code to obtain the current characteristic.  However this can be
+difficult and most PNG gamma correction only requires an approximate value.
+
+By default, if png_set_alpha_mode() is not called, libpng assumes that all
+values are unencoded, linear, values and that the output device also has a
+linear characteristic.  This is only very rarely correct - it is invariably
+better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
+default if you don't know what the right answer is!
+
+The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
+10.6) which used a correction table to implement a somewhat lower gamma on an
+otherwise sRGB system.
+
+Both these values are reserved (not simple gamma values) in order to allow
+more precise correction internally in the future.
+
+NOTE: the values can be passed to either the fixed or floating
+point APIs, but the floating point API will also accept floating point
+values.
+
+The second thing you may need to tell libpng about is how your system handles
+alpha channel information.  Some, but not all, PNG files contain an alpha
+channel.  To display these files correctly you need to compose the data onto a
+suitable background, as described in the PNG specification.
+
+Libpng only supports composing onto a single color (using png_set_background;
+see below).  Otherwise you must do the composition yourself and, in this case,
+you may need to call png_set_alpha_mode:
+
+   #if PNG_LIBPNG_VER >= 10504
+      png_set_alpha_mode(png_ptr, mode, screen_gamma);
+   #else
+      png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma);
+   #endif
+
+The screen_gamma value is the same as the argument to png_set_gamma; however,
+how it affects the output depends on the mode.  png_set_alpha_mode() sets the
+file gamma default to 1/screen_gamma, so normally you don't need to call
+png_set_gamma.  If you need different defaults call png_set_gamma() before
+png_set_alpha_mode() - if you call it after it will override the settings made
+by png_set_alpha_mode().
+
+The mode is as follows:
+
+    PNG_ALPHA_PNG: The data is encoded according to the PNG
+specification.  Red, green and blue, or gray, components are
+gamma encoded color values and are not premultiplied by the
+alpha value.  The alpha value is a linear measure of the
+contribution of the pixel to the corresponding final output pixel.
+
+You should normally use this format if you intend to perform
+color correction on the color values; most, maybe all, color
+correction software has no handling for the alpha channel and,
+anyway, the math to handle pre-multiplied component values is
+unnecessarily complex.
+
+Before you do any arithmetic on the component values you need
+to remove the gamma encoding and multiply out the alpha
+channel.  See the PNG specification for more detail.  It is
+important to note that when an image with an alpha channel is
+scaled, linear encoded, pre-multiplied component values must
+be used!
+
+The remaining modes assume you don't need to do any further color correction or
+that if you do, your color correction software knows all about alpha (it
+probably doesn't!).  They 'associate' the alpha with the color information by
+storing color channel values that have been scaled by the alpha.  The
+advantage is that the color channels can be resampled (the image can be
+scaled) in this form.  The disadvantage is that normal practice is to store
+linear, not (gamma) encoded, values and this requires 16-bit channels for
+still images rather than the 8-bit channels that are just about sufficient if
+gamma encoding is used.  In addition all non-transparent pixel values,
+including completely opaque ones, must be gamma encoded to produce the final
+image.  These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+described below (the latter being the two common names for associated alpha
+color channels). Note that PNG files always contain non-associated color
+channels; png_set_alpha_mode() with one of the modes causes the decoder to
+convert the pixels to an associated form before returning them to your
+application. 
+
+Since it is not necessary to perform arithmetic on opaque color values so
+long as they are not to be resampled and are in the final color space it is
+possible to optimize the handling of alpha by storing the opaque pixels in
+the PNG format (adjusted for the output color space) while storing partially
+opaque pixels in the standard, linear, format.  The accuracy required for
+standard alpha composition is relatively low, because the pixels are
+isolated, therefore typically the accuracy loss in storing 8-bit linear
+values is acceptable.  (This is not true if the alpha channel is used to
+simulate transparency over large areas - use 16 bits or the PNG mode in
+this case!)  This is the 'OPTIMIZED' mode.  For this mode a pixel is
+treated as opaque only if the alpha value is equal to the maximum value.
+
+    PNG_ALPHA_STANDARD:  The data libpng produces is encoded in the
+standard way assumed by most correctly written graphics software.
+The gamma encoding will be removed by libpng and the
+linear component values will be pre-multiplied by the
+alpha channel.
+
+With this format the final image must be re-encoded to
+match the display gamma before the image is displayed.
+If your system doesn't do that, yet still seems to
+perform arithmetic on the pixels without decoding them,
+it is broken - check out the modes below.
+
+With PNG_ALPHA_STANDARD libpng always produces linear
+component values, whatever screen_gamma you supply.  The
+screen_gamma value is, however, used as a default for
+the file gamma if the PNG file has no gamma information.
+
+If you call png_set_gamma() after png_set_alpha_mode() you
+will override the linear encoding.  Instead the
+pre-multiplied pixel values will be gamma encoded but
+the alpha channel will still be linear.  This may
+actually match the requirements of some broken software,
+but it is unlikely.
+
+While linear 8-bit data is often used it has
+insufficient precision for any image with a reasonable
+dynamic range.  To avoid problems, and if your software
+supports it, use png_set_expand_16() to force all
+components to 16 bits.
+
+    PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD
+except that completely opaque pixels are gamma encoded according to
+the screen_gamma value.  Pixels with alpha less than 1.0
+will still have linear components.
+
+Use this format if you have control over your
+compositing software and so don't do other arithmetic
+(such as scaling) on the data you get from libpng.  Your
+compositing software can simply copy opaque pixels to
+the output but still has linear values for the
+non-opaque pixels.
+
+In normal compositing, where the alpha channel encodes
+partial pixel coverage (as opposed to broad area
+translucency), the inaccuracies of the 8-bit
+representation of non-opaque pixels are irrelevant.
+
+You can also try this format if your software is broken;
+it might look better.
+
+    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD; however, all component
+values, including the alpha channel are gamma encoded.  This is
+broken because, in practice, no implementation that uses this choice
+correctly undoes the encoding before handling alpha composition.  Use this
+choice only if other serious errors in the software or hardware you use
+mandate it.  In most cases of broken software or hardware the bug in the
+final display manifests as a subtle halo around composited parts of the
+image.  You may not even perceive this as a halo; the composited part of
+the image may simply appear separate from the background, as though it had
+been cut out of paper and pasted on afterward.
+
+If you don't have to deal with bugs in software or hardware, or if you can fix
+them, there are three recommended ways of using png_set_alpha_mode():
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
+       screen_gamma);
+
+You can do color correction on the result (libpng does not currently
+support color correction internally).  When you handle the alpha channel
+you need to undo the gamma encoding and multiply out the alpha.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
+       screen_gamma);
+   png_set_expand_16(png_ptr);
+
+If you are using the high level interface, don't call png_set_expand_16();
+instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
+
+With this mode you can't do color correction, but you can do arithmetic,
+including composition and scaling, on the data without further processing.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
+       screen_gamma);
+
+You can avoid the expansion to 16-bit components with this mode, but you
+lose the ability to scale the image or perform other linear arithmetic.
+All you can do is compose the result onto a matching output.  Since this
+mode is libpng-specific you also need to write your own composition
+software.
+
+The following are examples of calls to png_set_alpha_mode to achieve the
+required overall gamma correction and, where necessary, alpha
+premultiplication.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+
+Choices for the alpha_mode are
+
+    PNG_ALPHA_PNG           0 /* according to the PNG standard */
+    PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
+    PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
+    PNG_ALPHA_PREMULTIPLIED 1 /* as above */
+    PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
+    PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
+
+PNG_ALPHA_PNG is the default libpng handling of the alpha channel. It is not
+pre-multiplied into the color components. In addition the call states
+that the output is for a sRGB system and causes all PNG files without gAMA
+chunks to be assumed to be encoded using sRGB.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+In this case the output is assumed to be something like an sRGB conformant
+display preceded by a power-law lookup table of power 1.45.  This is how
+early Mac systems behaved.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+
+This is the classic Jim Blinn approach and will work in academic
+environments where everything is done by the book.  It has the shortcoming
+of assuming that input PNG data with no gamma information is linear - this
+is unlikely to be correct unless the PNG files were generated locally.
+Most of the time the output precision will be so low as to show
+significant banding in dark areas of the image.
+
+    png_set_expand_16(pp);
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+
+This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
+are assumed to have the sRGB encoding if not marked with a gamma value and
+the output is always 16 bits per component.  This permits accurate scaling
+and processing of the data.  If you know that your input PNG files were
+generated locally you might need to replace PNG_DEFAULT_sRGB with the
+correct value for your system.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+
+If you just need to composite the PNG image onto an existing background
+and if you control the code that does this you can use the optimization
+setting.  In this case you just copy completely opaque pixels to the
+output.  For pixels that are not completely transparent (you just skip
+those) you do the composition math using png_composite or png_composite_16
+below then encode the resultant 8-bit or 16-bit values to match the output
+encoding.
+
+    Other cases
+
+If neither the PNG nor the standard linear encoding work for you because
+of the software or hardware you use then you have a big problem.  The PNG
+case will probably result in halos around the image.  The linear encoding
+will probably result in a washed out, too bright, image (it's actually too
+contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
+substantially reduce the halos.  Alternatively try:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+
+This option will also reduce the halos, but there will be slight dark
+halos round the opaque parts of the image where the background is light.
+In the OPTIMIZED mode the halos will be light halos where the background
+is dark.  Take your pick - the halos are unavoidable unless you can get
+your hardware/software fixed!  (The OPTIMIZED approach is slightly
+faster.)
+
+When the default gamma of PNG files doesn't match the output gamma.
+If you have PNG files with no gamma information png_set_alpha_mode allows
+you to provide a default gamma, but it also sets the output gamma to the
+matching value.  If you know your PNG files have a gamma that doesn't
+match the output you can take advantage of the fact that
+png_set_alpha_mode always sets the output gamma but only sets the PNG
+default if it is not already set:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+The first call sets both the default and the output gamma values, the
+second call overrides the output gamma without changing the default.  This
+is easier than achieving the same effect with png_set_gamma.  You must use
+PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+fire if more than one call to png_set_alpha_mode and png_set_background is
+made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+are ignored.
+
+If you don't need, or can't handle, the alpha channel you can call
+png_set_background() to remove it by compositing against a fixed color.  Don't
+call png_set_strip_alpha() to do this - it will leave spurious pixel values in
+transparent parts of this image.
+
+   png_set_background(png_ptr, &background_color,
+       PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
+
+The background_color is an RGB or grayscale value according to the data format
+libpng will produce for you.  Because you don't yet know the format of the PNG
+file, if you call png_set_background at this point you must arrange for the
+format produced by libpng to always have 8-bit or 16-bit components and then
+store the color as an 8-bit or 16-bit color as appropriate.  The color contains
+separate gray and RGB component values, so you can let libpng produce gray or
+RGB output according to the input format, but low bit depth grayscale images
+must always be converted to at least 8-bit format.  (Even though low bit depth
+grayscale images can't have an alpha channel they can have a transparent
+color!)
+
+You set the transforms you need later, either as flags to the high level
+interface or libpng API calls for the low level interface.  For reference the
+settings and API calls required are:
+
+8-bit values:
+   PNG_TRANSFORM_SCALE_16 | PNG_EXPAND
+   png_set_expand(png_ptr); png_set_scale_16(png_ptr);
+
+   If you must get exactly the same inaccurate results
+   produced by default in versions prior to libpng-1.5.4,
+   use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr)
+   instead.
+
+16-bit values:
+   PNG_TRANSFORM_EXPAND_16
+   png_set_expand_16(png_ptr);
+
+In either case palette image data will be expanded to RGB.  If you just want
+color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
+to the list.
+
+Calling png_set_background before the PNG file header is read will not work
+prior to libpng-1.5.4.  Because the failure may result in unexpected warnings or
+errors it is therefore much safer to call png_set_background after the head has
+been read.  Unfortunately this means that prior to libpng-1.5.4 it cannot be
+used with the high level interface.
+
+The high-level read interface
+
+At this point there are two ways to proceed; through the high-level
+read interface, or through a sequence of low-level read operations.
+You can use the high-level interface if (a) you are willing to read
+the entire image into memory, and (b) the input transformations
+you want to do are limited to the following set:
+
+    PNG_TRANSFORM_IDENTITY      No transformation
+    PNG_TRANSFORM_SCALE_16      Strip 16-bit samples to
+                                8-bit accurately
+    PNG_TRANSFORM_STRIP_16      Chop 16-bit samples to
+                                8-bit less accurately
+    PNG_TRANSFORM_STRIP_ALPHA   Discard the alpha channel
+    PNG_TRANSFORM_PACKING       Expand 1, 2 and 4-bit
+                                samples to bytes
+    PNG_TRANSFORM_PACKSWAP      Change order of packed
+                                pixels to LSB first
+    PNG_TRANSFORM_EXPAND        Perform set_expand()
+    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
+    PNG_TRANSFORM_SHIFT         Normalize pixels to the
+                                sBIT depth
+    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
+                                to BGRA
+    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
+                                to AG
+    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
+                                to transparency
+    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
+    PNG_TRANSFORM_GRAY_TO_RGB   Expand grayscale samples
+                                to RGB (or GA to RGBA)
+    PNG_TRANSFORM_EXPAND_16     Expand samples to 16 bits
+
+(This excludes setting a background color, doing gamma transformation,
+quantizing, and setting filler.)  If this is the case, simply do this:
+
+    png_read_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some
+set of transformation flags.  This call is equivalent to png_read_info(),
+followed the set of transformations indicated by the transform mask,
+then png_read_image(), and finally png_read_end().
+
+(The final parameter of this call is not yet used.  Someday it might point
+to transformation parameters required by some future input transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_read_png().
+
+After you have called png_read_png(), you can retrieve the image data
+with
+
+   row_pointers = png_get_rows(png_ptr, info_ptr);
+
+where row_pointers is an array of pointers to the pixel data for each row:
+
+   png_bytep row_pointers[height];
+
+If you know your image size and pixel size ahead of time, you can allocate
+row_pointers prior to calling png_read_png() with
+
+   if (height > PNG_UINT_32_MAX/(sizeof (png_byte)))
+      png_error (png_ptr,
+          "Image is too tall to process in memory");
+
+   if (width > PNG_UINT_32_MAX/pixel_size)
+      png_error (png_ptr,
+          "Image is too wide to process in memory");
+
+   row_pointers = png_malloc(png_ptr,
+       height*(sizeof (png_bytep)));
+
+   for (int i=0; i<height, i++)
+      row_pointers[i]=NULL;  /* security precaution */
+
+   for (int i=0; i<height, i++)
+      row_pointers[i]=png_malloc(png_ptr,
+          width*pixel_size);
+
+   png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+Alternatively you could allocate your image in one big block and define
+row_pointers[i] to point into the proper places in your block, but first
+be sure that your platform is able to allocate such a large buffer:
+
+   /* Guard against integer overflow */
+   if (height > PNG_SIZE_MAX/(width*pixel_size)) {
+        png_error(png_ptr,"image_data buffer would be too large");
+   }
+
+   png_bytep buffer=png_malloc(png_ptr,height*width*pixel_size);
+
+   for (int i=0; i<height, i++)
+      row_pointers[i]=buffer+i*width*pixel_size;
+
+   png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+If you use png_set_rows(), the application is responsible for freeing
+row_pointers (and row_pointers[i], if they were separately allocated).
+
+If you don't allocate row_pointers ahead of time, png_read_png() will
+do it, and it'll be free'ed by libpng when you call png_destroy_*().
+
+The low-level read interface
+
+If you are going the low-level route, you are now ready to read all
+the file information up to the actual image data.  You do this with a
+call to png_read_info().
+
+    png_read_info(png_ptr, info_ptr);
+
+This will process all chunks up to but not including the image data.
+
+This also copies some of the data from the PNG file into the decode structure
+for use in later transformations.  Important information copied in is:
+
+1) The PNG file gamma from the gAMA chunk.  This overwrites the default value
+provided by an earlier call to png_set_gamma or png_set_alpha_mode.
+
+2) Prior to libpng-1.5.4 the background color from a bKGd chunk.  This
+damages the information provided by an earlier call to png_set_background
+resulting in unexpected behavior.  Libpng-1.5.4 no longer does this.
+
+3) The number of significant bits in each component value.  Libpng uses this to
+optimize gamma handling by reducing the internal lookup table sizes.
+
+4) The transparent color information from a tRNS chunk.  This can be modified by
+a later call to png_set_tRNS.
+
+Querying the info structure
+
+Functions are used to get the information from the info_ptr once it
+has been read.  Note that these fields may not be completely filled
+in until png_read_end() has read the chunk data following the image.
+
+    png_get_IHDR(png_ptr, info_ptr, &width, &height,
+       &bit_depth, &color_type, &interlace_type,
+       &compression_type, &filter_method);
+
+    width          - holds the width of the image
+                     in pixels (up to 2^31).
+
+    height         - holds the height of the image
+                     in pixels (up to 2^31).
+
+    bit_depth      - holds the bit depth of one of the
+                     image channels.  (valid values are
+                     1, 2, 4, 8, 16 and depend also on
+                     the color_type.  See also
+                     significant bits (sBIT) below).
+
+    color_type     - describes which color/alpha channels
+                         are present.
+                     PNG_COLOR_TYPE_GRAY
+                        (bit depths 1, 2, 4, 8, 16)
+                     PNG_COLOR_TYPE_GRAY_ALPHA
+                        (bit depths 8, 16)
+                     PNG_COLOR_TYPE_PALETTE
+                        (bit depths 1, 2, 4, 8)
+                     PNG_COLOR_TYPE_RGB
+                        (bit_depths 8, 16)
+                     PNG_COLOR_TYPE_RGB_ALPHA
+                        (bit_depths 8, 16)
+
+                     PNG_COLOR_MASK_PALETTE
+                     PNG_COLOR_MASK_COLOR
+                     PNG_COLOR_MASK_ALPHA
+
+    interlace_type - (PNG_INTERLACE_NONE or
+                     PNG_INTERLACE_ADAM7)
+
+    compression_type - (must be PNG_COMPRESSION_TYPE_BASE
+                     for PNG 1.0)
+
+    filter_method  - (must be PNG_FILTER_TYPE_BASE
+                     for PNG 1.0, and can also be
+                     PNG_INTRAPIXEL_DIFFERENCING if
+                     the PNG datastream is embedded in
+                     a MNG-1.0 datastream)
+
+    Any of width, height, color_type, bit_depth,
+    interlace_type, compression_type, or filter_method can
+    be NULL if you are not interested in their values.
+
+    Note that png_get_IHDR() returns 32-bit data into
+    the application's width and height variables.
+    This is an unsafe situation if these are not png_uint_32
+    variables.  In such situations, the
+    png_get_image_width() and png_get_image_height()
+    functions described below are safer.
+
+    width            = png_get_image_width(png_ptr,
+                         info_ptr);
+
+    height           = png_get_image_height(png_ptr,
+                         info_ptr);
+
+    bit_depth        = png_get_bit_depth(png_ptr,
+                         info_ptr);
+
+    color_type       = png_get_color_type(png_ptr,
+                         info_ptr);
+
+    interlace_type   = png_get_interlace_type(png_ptr,
+                         info_ptr);
+
+    compression_type = png_get_compression_type(png_ptr,
+                         info_ptr);
+
+    filter_method    = png_get_filter_type(png_ptr,
+                         info_ptr);
+
+    channels = png_get_channels(png_ptr, info_ptr);
+
+    channels       - number of channels of info for the
+                     color type (valid values are 1 (GRAY,
+                     PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
+                     4 (RGB_ALPHA or RGB + filler byte))
+
+    rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+    rowbytes       - number of bytes needed to hold a row
+                     This value, the bit_depth, color_type,
+                     and the number of channels can change
+                     if you use transforms such as
+                     png_set_expand(). See
+                     png_read_update_info(), below.
+
+    signature = png_get_signature(png_ptr, info_ptr);
+
+    signature      - holds the signature read from the
+                     file (if any).  The data is kept in
+                     the same offset it would be if the
+                     whole signature were read (i.e. if an
+                     application had already read in 4
+                     bytes of signature before starting
+                     libpng, the remaining 4 bytes would
+                     be in signature[4] through signature[7]
+                     (see png_set_sig_bytes())).
+
+These are also important, but their validity depends on whether the chunk
+has been read.  The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
+png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
+data has been read, or zero if it is missing.  The parameters to the
+png_get_<chunk> are set directly if they are simple data types, or a
+pointer into the info_ptr is returned for any complex types.
+
+The colorspace data from gAMA, cHRM, sRGB, iCCP, and sBIT chunks
+is simply returned to give the application information about how the
+image was encoded.  Libpng itself only does transformations using the file
+gamma when combining semitransparent pixels with the background color, and,
+since libpng-1.6.0, when converting between 8-bit sRGB and 16-bit linear pixels
+within the simplified API.  Libpng also uses the file gamma when converting
+RGB to gray, beginning with libpng-1.0.5, if the application calls
+png_set_rgb_to_gray()).
+
+    png_get_PLTE(png_ptr, info_ptr, &palette,
+                     &num_palette);
+
+    palette        - the palette for the file
+                     (array of png_color)
+
+    num_palette    - number of entries in the palette
+
+    png_get_gAMA(png_ptr, info_ptr, &file_gamma);
+    png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
+
+    file_gamma     - the gamma at which the file is
+                     written (PNG_INFO_gAMA)
+
+    int_file_gamma - 100,000 times the gamma at which the
+                     file is written
+
+    png_get_cHRM(png_ptr, info_ptr,  &white_x, &white_y, &red_x,
+                     &red_y, &green_x, &green_y, &blue_x, &blue_y)
+    png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z,
+                     &green_X, &green_Y, &green_Z, &blue_X, &blue_Y,
+                     &blue_Z)
+    png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x,
+                     &int_white_y, &int_red_x, &int_red_y,
+                     &int_green_x, &int_green_y, &int_blue_x,
+                     &int_blue_y)
+    png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y,
+                     &int_red_Z, &int_green_X, &int_green_Y,
+                     &int_green_Z, &int_blue_X, &int_blue_Y,
+                     &int_blue_Z)
+
+    {white,red,green,blue}_{x,y}
+                     A color space encoding specified using the
+                     chromaticities of the end points and the
+                     white point. (PNG_INFO_cHRM)
+
+    {red,green,blue}_{X,Y,Z}
+                     A color space encoding specified using the
+                     encoding end points - the CIE tristimulus
+                     specification of the intended color of the red,
+                     green and blue channels in the PNG RGB data.
+                     The white point is simply the sum of the three
+                     end points. (PNG_INFO_cHRM)
+
+    png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
+
+    srgb_intent -    the rendering intent (PNG_INFO_sRGB)
+                     The presence of the sRGB chunk
+                     means that the pixel data is in the
+                     sRGB color space.  This chunk also
+                     implies specific values of gAMA and
+                     cHRM.
+
+    png_get_iCCP(png_ptr, info_ptr, &name,
+       &compression_type, &profile, &proflen);
+
+    name             - The profile name.
+
+    compression_type - The compression type; always
+                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+                       You may give NULL to this argument to
+                       ignore it.
+
+    profile          - International Color Consortium color
+                       profile data. May contain NULs.
+
+    proflen          - length of profile data in bytes.
+
+    png_get_sBIT(png_ptr, info_ptr, &sig_bit);
+
+    sig_bit        - the number of significant bits for
+                     (PNG_INFO_sBIT) each of the gray,
+                     red, green, and blue channels,
+                     whichever are appropriate for the
+                     given color type (png_color_16)
+
+    png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
+                     &num_trans, &trans_color);
+
+    trans_alpha    - array of alpha (transparency)
+                     entries for palette (PNG_INFO_tRNS)
+
+    num_trans      - number of transparent entries
+                     (PNG_INFO_tRNS)
+
+    trans_color    - graylevel or color sample values of
+                     the single transparent color for
+                     non-paletted images (PNG_INFO_tRNS)
+
+    png_get_eXIf_1(png_ptr, info_ptr, &num_exif, &exif);
+                     (PNG_INFO_eXIf)
+
+    exif           - Exif profile (array of png_byte)
+
+    png_get_hIST(png_ptr, info_ptr, &hist);
+                     (PNG_INFO_hIST)
+
+    hist           - histogram of palette (array of
+                     png_uint_16)
+
+    png_get_tIME(png_ptr, info_ptr, &mod_time);
+
+    mod_time       - time image was last modified
+                    (PNG_VALID_tIME)
+
+    png_get_bKGD(png_ptr, info_ptr, &background);
+
+    background     - background color (of type
+                     png_color_16p) (PNG_VALID_bKGD)
+                     valid 16-bit red, green and blue
+                     values, regardless of color_type
+
+    num_comments   = png_get_text(png_ptr, info_ptr,
+                     &text_ptr, &num_text);
+
+    num_comments   - number of comments
+
+    text_ptr       - array of png_text holding image
+                     comments
+
+    text_ptr[i].compression - type of compression used
+                 on "text" PNG_TEXT_COMPRESSION_NONE
+                           PNG_TEXT_COMPRESSION_zTXt
+                           PNG_ITXT_COMPRESSION_NONE
+                           PNG_ITXT_COMPRESSION_zTXt
+
+    text_ptr[i].key   - keyword for comment.  Must contain
+                         1-79 characters.
+
+    text_ptr[i].text  - text comments for current
+                         keyword.  Can be empty.
+
+    text_ptr[i].text_length - length of text string,
+                 after decompression, 0 for iTXt
+
+    text_ptr[i].itxt_length - length of itxt string,
+                 after decompression, 0 for tEXt/zTXt
+
+    text_ptr[i].lang  - language of comment (empty
+                         string for unknown).
+
+    text_ptr[i].lang_key  - keyword in UTF-8
+                         (empty string for unknown).
+
+    Note that the itxt_length, lang, and lang_key
+    members of the text_ptr structure only exist when the
+    library is built with iTXt chunk support.  Prior to
+    libpng-1.4.0 the library was built by default without
+    iTXt support. Also note that when iTXt is supported,
+    they contain NULL pointers when the "compression"
+    field contains PNG_TEXT_COMPRESSION_NONE or
+    PNG_TEXT_COMPRESSION_zTXt.
+
+    num_text       - number of comments (same as
+                     num_comments; you can put NULL here
+                     to avoid the duplication)
+
+    Note while png_set_text() will accept text, language,
+    and translated keywords that can be NULL pointers, the
+    structure returned by png_get_text will always contain
+    regular zero-terminated C strings.  They might be
+    empty strings but they will never be NULL pointers.
+
+    num_spalettes = png_get_sPLT(png_ptr, info_ptr,
+       &palette_ptr);
+
+    num_spalettes  - number of sPLT chunks read.
+
+    palette_ptr    - array of palette structures holding
+                     contents of one or more sPLT chunks
+                     read.
+
+    png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
+       &unit_type);
+
+    offset_x       - positive offset from the left edge
+                     of the screen (can be negative)
+
+    offset_y       - positive offset from the top edge
+                     of the screen (can be negative)
+
+    unit_type      - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+    png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
+       &unit_type);
+
+    res_x          - pixels/unit physical resolution in
+                     x direction
+
+    res_y          - pixels/unit physical resolution in
+                     x direction
+
+    unit_type      - PNG_RESOLUTION_UNKNOWN,
+                     PNG_RESOLUTION_METER
+
+    png_get_sCAL(png_ptr, info_ptr, &unit, &width,
+       &height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+
+    height      - height of a pixel in physical scale units
+                 (width and height are doubles)
+
+    png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
+       &height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+                  (expressed as a string)
+
+    height      - height of a pixel in physical scale units
+                 (width and height are strings like "2.54")
+
+    num_unknown_chunks = png_get_unknown_chunks(png_ptr,
+       info_ptr, &unknowns)
+
+    unknowns          - array of png_unknown_chunk
+                        structures holding unknown chunks
+
+    unknowns[i].name  - name of unknown chunk
+
+    unknowns[i].data  - data of unknown chunk
+
+    unknowns[i].size  - size of unknown chunk's data
+
+    unknowns[i].location - position of chunk in file
+
+    The value of "i" corresponds to the order in which the
+    chunks were read from the PNG file or inserted with the
+    png_set_unknown_chunks() function.
+
+    The value of "location" is a bitwise "or" of
+
+         PNG_HAVE_IHDR  (0x01)
+         PNG_HAVE_PLTE  (0x02)
+         PNG_AFTER_IDAT (0x08)
+
+The data from the pHYs chunk can be retrieved in several convenient
+forms:
+
+    res_x = png_get_x_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_y = png_get_y_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_x_and_y = png_get_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_x = png_get_x_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    res_y = png_get_y_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    res_x_and_y = png_get_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
+       info_ptr)
+
+    Each of these returns 0 [signifying "unknown"] if
+       the data is not present or if res_x is 0;
+       res_x_and_y is 0 if res_x != res_y
+
+    Note that because of the way the resolutions are
+       stored internally, the inch conversions won't
+       come out to exactly even number.  For example,
+       72 dpi is stored as 0.28346 pixels/meter, and
+       when this is retrieved it is 71.9988 dpi, so
+       be sure to round the returned value appropriately
+       if you want to display a reasonable-looking result.
+
+The data from the oFFs chunk can be retrieved in several convenient
+forms:
+
+    x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
+
+    y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
+
+    x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
+
+    y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
+
+    Each of these returns 0 [signifying "unknown" if both
+       x and y are 0] if the data is not present or if the
+       chunk is present but the unit is the pixel.  The
+       remark about inexact inch conversions applies here
+       as well, because a value in inches can't always be
+       converted to microns and back without some loss
+       of precision.
+
+For more information, see the
+PNG specification for chunk contents.  Be careful with trusting
+rowbytes, as some of the transformations could increase the space
+needed to hold a row (expand, filler, gray_to_rgb, etc.).
+See png_read_update_info(), below.
+
+A quick word about text_ptr and num_text.  PNG stores comments in
+keyword/text pairs, one pair per chunk, with no limit on the number
+of text chunks, and a 2^31 byte limit on their size.  While there are
+suggested keywords, there is no requirement to restrict the use to these
+strings.  It is strongly suggested that keywords and text be sensible
+to humans (that's the point), so don't use abbreviations.  Non-printing
+symbols are not allowed.  See the PNG specification for more details.
+There is also no requirement to have text after the keyword.
+
+Keywords should be limited to 79 Latin-1 characters without leading or
+trailing spaces, but non-consecutive spaces are allowed within the
+keyword.  It is possible to have the same keyword any number of times.
+The text_ptr is an array of png_text structures, each holding a
+pointer to a language string, a pointer to a keyword and a pointer to
+a text string.  The text string, language code, and translated
+keyword may be empty or NULL pointers.  The keyword/text
+pairs are put into the array in the order that they are received.
+However, some or all of the text chunks may be after the image, so, to
+make sure you have read all the text chunks, don't mess with these
+until after you read the stuff after the image.  This will be
+mentioned again below in the discussion that goes with png_read_end().
+
+Input transformations
+
+After you've read the header information, you can set up the library
+to handle any special transformations of the image data.  The various
+ways to transform the data will be described in the order that they
+should occur.  This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths.
+
+Transformations you request are ignored if they don't have any meaning for a
+particular input data format.  However some transformations can have an effect
+as a result of a previous transformation.  If you specify a contradictory set of
+transformations, for example both adding and removing the alpha channel, you
+cannot predict the final result.
+
+The color used for the transparency values should be supplied in the same
+format/depth as the current image data.  It is stored in the same format/depth
+as the image data in a tRNS chunk, so this is what libpng expects for this data.
+
+The color used for the background value depends on the need_expand argument as
+described below.
+
+Data will be decoded into the supplied row buffers packed into bytes
+unless the library has been told to transform it into another format.
+For example, 4 bit/pixel paletted or grayscale data will be returned
+2 pixels/byte with the leftmost pixel in the high-order bits of the byte,
+unless png_set_packing() is called.  8-bit RGB data will be stored
+in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
+is called to insert filler bytes, either before or after each RGB triplet.
+
+16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
+byte of the color value first, unless png_set_scale_16() is called to
+transform it to regular RGB RGB triplets, or png_set_filler() or
+png_set_add alpha() is called to insert two filler bytes, either before
+or after each RRGGBB triplet.  Similarly, 8-bit or 16-bit grayscale data can
+be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(),
+or png_set_scale_16().
+
+The following code transforms grayscale images of less than 8 to 8 bits,
+changes paletted images to RGB, and adds a full alpha channel if there is
+transparency information in a tRNS chunk.  This is most useful on
+grayscale images with bit depths of 2 or 4 or if there is a multiple-image
+viewing application that wishes to treat all images in the same way.
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_palette_to_rgb(png_ptr);
+
+    if (png_get_valid(png_ptr, info_ptr,
+        PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
+
+    if (color_type == PNG_COLOR_TYPE_GRAY &&
+        bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+The first two functions are actually aliases for png_set_expand(), added
+in libpng version 1.0.4, with the function names expanded to improve code
+readability.  In some future version they may actually do different
+things.
+
+As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
+added.  It expands the sample depth without changing tRNS to alpha.
+
+As of libpng version 1.5.2, png_set_expand_16() was added.  It behaves as
+png_set_expand(); however, the resultant channels have 16 bits rather than 8.
+Use this when the output color or gray channels are made linear to avoid fairly
+severe accuracy loss.
+
+   if (bit_depth < 16)
+      png_set_expand_16(png_ptr);
+
+PNG can have files with 16 bits per channel.  If you only can handle
+8 bits per channel, this will strip the pixels down to 8-bit.
+
+    if (bit_depth == 16)
+#if PNG_LIBPNG_VER >= 10504
+       png_set_scale_16(png_ptr);
+#else
+       png_set_strip_16(png_ptr);
+#endif
+
+(The more accurate "png_set_scale_16()" API became available in libpng version
+1.5.4).
+
+If you need to process the alpha channel on the image separately from the image
+data (for example if you convert it to a bitmap mask) it is possible to have
+libpng strip the channel leaving just RGB or gray data:
+
+    if (color_type & PNG_COLOR_MASK_ALPHA)
+       png_set_strip_alpha(png_ptr);
+
+If you strip the alpha channel you need to find some other way of dealing with
+the information.  If, instead, you want to convert the image to an opaque
+version with no alpha channel use png_set_background; see below.
+
+As of libpng version 1.5.2, almost all useful expansions are supported, the
+major ommissions are conversion of grayscale to indexed images (which can be
+done trivially in the application) and conversion of indexed to grayscale (which
+can be done by a trivial manipulation of the palette.)
+
+In the following table, the 01 means grayscale with depth<8, 31 means
+indexed with depth<8, other numerals represent the color type, "T" means
+the tRNS chunk is present, A means an alpha channel is present, and O
+means tRNS or alpha is present but all pixels in the image are opaque.
+
+  FROM  01  31   0  0T  0O   2  2T  2O   3  3T  3O  4A  4O  6A  6O
+   TO
+   01    -  [G]  -   -   -   -   -   -   -   -   -   -   -   -   -
+   31   [Q]  Q  [Q] [Q] [Q]  Q   Q   Q   Q   Q   Q  [Q] [Q]  Q   Q
+    0    1   G   +   .   .   G   G   G   G   G   G   B   B  GB  GB
+   0T    lt  Gt  t   +   .   Gt  G   G   Gt  G   G   Bt  Bt GBt GBt
+   0O    lt  Gt  t   .   +   Gt  Gt  G   Gt  Gt  G   Bt  Bt GBt GBt
+    2    C   P   C   C   C   +   .   .   C   -   -  CB  CB   B   B
+   2T    Ct  -   Ct  C   C   t   +   t   -   -   -  CBt CBt  Bt  Bt
+   2O    Ct  -   Ct  C   C   t   t   +   -   -   -  CBt CBt  Bt  Bt
+    3   [Q]  p  [Q] [Q] [Q]  Q   Q   Q   +   .   .  [Q] [Q]  Q   Q
+   3T   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   +   t  [Qt][Qt] Qt  Qt
+   3O   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   t   +  [Qt][Qt] Qt  Qt
+   4A    lA  G   A   T   T   GA  GT  GT  GA  GT  GT  +   BA  G  GBA
+   4O    lA GBA  A   T   T   GA  GT  GT  GA  GT  GT  BA  +  GBA  G
+   6A    CA  PA  CA  C   C   A   T  tT   PA  P   P   C  CBA  +   BA
+   6O    CA PBA  CA  C   C   A  tT   T   PA  P   P  CBA  C   BA  +
+
+Within the matrix,
+     "+" identifies entries where 'from' and 'to' are the same.
+     "-" means the transformation is not supported.
+     "." means nothing is necessary (a tRNS chunk can just be ignored).
+     "t" means the transformation is obtained by png_set_tRNS.
+     "A" means the transformation is obtained by png_set_add_alpha().
+     "X" means the transformation is obtained by png_set_expand().
+     "1" means the transformation is obtained by
+         png_set_expand_gray_1_2_4_to_8() (and by png_set_expand()
+         if there is no transparency in the original or the final
+         format).
+     "C" means the transformation is obtained by png_set_gray_to_rgb().
+     "G" means the transformation is obtained by png_set_rgb_to_gray().
+     "P" means the transformation is obtained by
+         png_set_expand_palette_to_rgb().
+     "p" means the transformation is obtained by png_set_packing().
+     "Q" means the transformation is obtained by png_set_quantize().
+     "T" means the transformation is obtained by
+         png_set_tRNS_to_alpha().
+     "B" means the transformation is obtained by
+         png_set_background(), or png_strip_alpha().
+
+When an entry has multiple transforms listed all are required to cause the
+right overall transformation.  When two transforms are separated by a comma
+either will do the job.  When transforms are enclosed in [] the transform should
+do the job but this is currently unimplemented - a different format will result
+if the suggested transformations are used.
+
+In PNG files, the alpha channel in an image
+is the level of opacity.  If you need the alpha channel in an image to
+be the level of transparency instead of opacity, you can invert the
+alpha channel (or the tRNS chunk data) after it's read, so that 0 is
+fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
+images) is fully transparent, with
+
+    png_set_invert_alpha(png_ptr);
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit
+files.  This code expands to 1 pixel per byte without changing the
+values of the pixels:
+
+    if (bit_depth < 8)
+       png_set_packing(png_ptr);
+
+PNG files have possible bit depths of 1, 2, 4, 8, and 16.  All pixels
+stored in a PNG image have been "scaled" or "shifted" up to the next
+higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
+to 8 bits/sample in the range [0, 255]).  However, it is also possible
+to convert the PNG pixel data back to the original bit depth of the
+image.  This call reduces the pixels back down to the original bit depth:
+
+    png_color_8p sig_bit;
+
+    if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
+       png_set_shift(png_ptr, sig_bit);
+
+PNG files store 3-color pixels in red, green, blue order.  This code
+changes the storage of the pixels to blue, green, red:
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_bgr(png_ptr);
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
+into 4 or 8 bytes for windowing systems that need them in this format:
+
+    if (color_type == PNG_COLOR_TYPE_RGB)
+       png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
+
+where "filler" is the 8-bit or 16-bit number to fill with, and the location
+is either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
+you want the filler before the RGB or after. When filling an 8-bit pixel,
+the least significant 8 bits of the number are used, if a 16-bit number is
+supplied.  This transformation does not affect images that already have full
+alpha channels.  To add an opaque alpha channel, use filler=0xffff and
+PNG_FILLER_AFTER which will generate RGBA pixels.
+
+Note that png_set_filler() does not change the color type.  If you want
+to do that, you can add a true alpha channel with
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+       color_type == PNG_COLOR_TYPE_GRAY)
+       png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
+
+where "filler" contains the alpha value to assign to each pixel.
+The png_set_add_alpha() function was added in libpng-1.2.7.
+
+If you are reading an image with an alpha channel, and you need the
+data as ARGB instead of the normal PNG format RGBA:
+
+    if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_swap_alpha(png_ptr);
+
+For some uses, you may want a grayscale image to be represented as
+RGB.  This code will do that conversion:
+
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+       png_set_gray_to_rgb(png_ptr);
+
+Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
+with alpha.
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_rgb_to_gray(png_ptr, error_action,
+          double red_weight, double green_weight);
+
+    error_action = 1: silently do the conversion
+
+    error_action = 2: issue a warning if the original
+                      image has any pixel where
+                      red != green or red != blue
+
+    error_action = 3: issue an error and abort the
+                      conversion if the original
+                      image has any pixel where
+                      red != green or red != blue
+
+    red_weight:       weight of red component
+
+    green_weight:     weight of green component
+                      If either weight is negative, default
+                      weights are used.
+
+In the corresponding fixed point API the red_weight and green_weight values are
+simply scaled by 100,000:
+
+    png_set_rgb_to_gray(png_ptr, error_action,
+       png_fixed_point red_weight,
+       png_fixed_point green_weight);
+
+If you have set error_action = 1 or 2, you can
+later check whether the image really was gray, after processing
+the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
+It will return a png_byte that is zero if the image was gray or
+1 if there were any non-gray pixels.  Background and sBIT data
+will be silently converted to grayscale, using the green channel
+data for sBIT, regardless of the error_action setting.
+
+The default values come from the PNG file cHRM chunk if present; otherwise, the
+defaults correspond to the ITU-R recommendation 709, and also the sRGB color
+space, as recommended in the Charles Poynton's Colour FAQ,
+Copyright (c) 2006-11-28 Charles Poynton, in section 9:
+
+<http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
+
+    Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
+
+Previous versions of this document, 1998 through 2002, recommended a slightly
+different formula:
+
+    Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+
+Libpng uses an integer approximation:
+
+    Y = (6968 * R + 23434 * G + 2366 * B)/32768
+
+The calculation is done in a linear colorspace, if the image gamma
+can be determined.
+
+The png_set_background() function has been described already; it tells libpng to
+composite images with alpha or simple transparency against the supplied
+background color.  For compatibility with versions of libpng earlier than
+libpng-1.5.4 it is recommended that you call the function after reading the file
+header, even if you don't want to use the color in a bKGD chunk, if one exists.
+
+If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
+you may use this color, or supply another color more suitable for
+the current display (e.g., the background color from a web page).  You
+need to tell libpng how the color is represented, both the format of the
+component values in the color (the number of bits) and the gamma encoding of the
+color.  The function takes two arguments, background_gamma_mode and need_expand
+to convey this information; however, only two combinations are likely to be
+useful:
+
+    png_color_16 my_background;
+    png_color_16p image_background;
+
+    if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+       png_set_background(png_ptr, image_background,
+           PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
+    else
+       png_set_background(png_ptr, &my_background,
+           PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
+
+The second call was described above - my_background is in the format of the
+final, display, output produced by libpng.  Because you now know the format of
+the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
+output and to retain palette images (the palette colors will be modified
+appropriately and the tRNS chunk removed.)  However, if you are doing this,
+take great care not to ask for transformations without checking first that
+they apply!
+
+In the first call the background color has the original bit depth and color type
+of the PNG file.  So, for palette images the color is supplied as a palette
+index and for low bit greyscale images the color is a reduced bit value in
+image_background->gray.
+
+If you didn't call png_set_gamma() before reading the file header, for example
+if you need your code to remain compatible with older versions of libpng prior
+to libpng-1.5.4, this is the place to call it.
+
+Do not call it if you called png_set_alpha_mode(); doing so will damage the
+settings put in place by png_set_alpha_mode().  (If png_set_alpha_mode() is
+supported then you can certainly do png_set_gamma() before reading the PNG
+header.)
+
+This API unconditionally sets the screen and file gamma values, so it will
+override the value in the PNG file unless it is called before the PNG file
+reading starts.  For this reason you must always call it with the PNG file
+value when you call it in this position:
+
+   if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
+      png_set_gamma(png_ptr, screen_gamma, file_gamma);
+
+   else
+      png_set_gamma(png_ptr, screen_gamma, 0.45455);
+
+If you need to reduce an RGB file to a paletted file, or if a paletted
+file has more entries than will fit on your screen, png_set_quantize()
+will do that.  Note that this is a simple match quantization that merely
+finds the closest color available.  This should work fairly well with
+optimized palettes, but fairly badly with linear color cubes.  If you
+pass a palette that is larger than maximum_colors, the file will
+reduce the number of colors in the palette so it will fit into
+maximum_colors.  If there is a histogram, libpng will use it to make
+more intelligent choices when reducing the palette.  If there is no
+histogram, it may not do as good a job.
+
+   if (color_type & PNG_COLOR_MASK_COLOR)
+   {
+      if (png_get_valid(png_ptr, info_ptr,
+          PNG_INFO_PLTE))
+      {
+         png_uint_16p histogram = NULL;
+
+         png_get_hIST(png_ptr, info_ptr,
+             &histogram);
+         png_set_quantize(png_ptr, palette, num_palette,
+            max_screen_colors, histogram, 1);
+      }
+
+      else
+      {
+         png_color std_color_cube[MAX_SCREEN_COLORS] =
+            { ... colors ... };
+
+         png_set_quantize(png_ptr, std_color_cube,
+            MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
+            NULL,0);
+      }
+   }
+
+PNG files describe monochrome as black being zero and white being one.
+The following code will reverse this (make black be one and white be
+zero):
+
+   if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
+      png_set_invert_mono(png_ptr);
+
+This function can also be used to invert grayscale and gray-alpha images:
+
+   if (color_type == PNG_COLOR_TYPE_GRAY ||
+       color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      png_set_invert_mono(png_ptr);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first).  This code changes the storage to the
+other way (little-endian, i.e. least significant bits first, the
+way PCs store them):
+
+    if (bit_depth == 16)
+       png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+    if (bit_depth < 8)
+       png_set_packswap(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs.  This is done by setting a callback
+with
+
+    png_set_read_user_transform_fn(png_ptr,
+        read_transform_fn);
+
+You must supply the function
+
+    void read_transform_fn(png_structp png_ptr, png_row_infop
+        row_info, png_bytep data)
+
+See pngtest.c for a working example.  Your function will be called
+after all of the other transformations have been processed.  Take care with
+interlaced images if you do the interlace yourself - the width of the row is the
+width in 'row_info', not the overall image width.
+
+If supported, libpng provides two information routines that you can use to find
+where you are in processing the image:
+
+   png_get_current_pass_number(png_structp png_ptr);
+   png_get_current_row_number(png_structp png_ptr);
+
+Don't try using these outside a transform callback - firstly they are only
+supported if user transforms are supported, secondly they may well return
+unexpected results unless the row is actually being processed at the moment they
+are called.
+
+With interlaced
+images the value returned is the row in the input sub-image image.  Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function, and you can inform libpng that your transform
+function will change the number of channels or bit depth with the
+function
+
+    png_set_user_transform_info(png_ptr, user_ptr,
+        user_depth, user_channels);
+
+The user's application, not libpng, is responsible for allocating and
+freeing any memory required for the user structure.
+
+You can retrieve the pointer via the function
+png_get_user_transform_ptr().  For example:
+
+    voidp read_user_transform_ptr =
+        png_get_user_transform_ptr(png_ptr);
+
+The last thing to handle is interlacing; this is covered in detail below,
+but you must call the function here if you want libpng to handle expansion
+of the interlaced image.
+
+    number_of_passes = png_set_interlace_handling(png_ptr);
+
+After setting the transformations, libpng can update your png_info
+structure to reflect any transformations you've requested with this
+call.
+
+    png_read_update_info(png_ptr, info_ptr);
+
+This is most useful to update the info structure's rowbytes
+field so you can use it to allocate your image memory.  This function
+will also update your palette with the correct screen_gamma and
+background if these have been given with the calls above.  You may
+only call png_read_update_info() once with a particular info_ptr.
+
+After you call png_read_update_info(), you can allocate any
+memory you need to hold the image.  The row data is simply
+raw byte data for all forms of images.  As the actual allocation
+varies among applications, no example will be given.  If you
+are allocating one large chunk, you will need to build an
+array of pointers to each row, as it will be needed for some
+of the functions below.
+
+Be sure that your platform can allocate the buffer that you'll need.
+libpng internally checks for oversize width, but you'll need to
+do your own check for number_of_rows*width*pixel_size if you are using
+a multiple-row buffer:
+
+   /* Guard against integer overflow */
+   if (number_of_rows > PNG_SIZE_MAX/(width*pixel_size)) {
+        png_error(png_ptr,"image_data buffer would be too large");
+   }
+
+Remember: Before you call png_read_update_info(), the png_get_*()
+functions return the values corresponding to the original PNG image.
+After you call png_read_update_info the values refer to the image
+that libpng will output.  Consequently you must call all the png_set_
+functions before you call png_read_update_info().  This is particularly
+important for png_set_interlace_handling() - if you are going to call
+png_read_update_info() you must call png_set_interlace_handling() before
+it unless you want to receive interlaced output.
+
+Reading image data
+
+After you've allocated memory, you can read the image data.
+The simplest way to do this is in one function call.  If you are
+allocating enough memory to hold the whole image, you can just
+call png_read_image() and libpng will read in all the image data
+and put it in the memory area supplied.  You will need to pass in
+an array of pointers to each row.
+
+This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() (unless you call
+png_read_update_info()) or call this function multiple times, or any
+of that other stuff necessary with png_read_rows().
+
+   png_read_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+   png_bytep row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to read in the whole image at once, you can
+use png_read_rows() instead.  If there is no interlacing (check
+interlace_type == PNG_INTERLACE_NONE), this is simple:
+
+    png_read_rows(png_ptr, row_pointers, NULL,
+        number_of_rows);
+
+where row_pointers is the same as in the png_read_image() call.
+
+If you are doing this just one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+    png_bytep row_pointer = row;
+    png_read_row(png_ptr, row_pointer, NULL);
+
+If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
+get somewhat harder.  The only current (PNG Specification version 1.2)
+interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
+a somewhat complicated 2D interlace scheme, known as Adam7, that
+breaks down an image into seven smaller images of varying size, based
+on an 8x8 grid.  This number is defined (from libpng 1.5) as
+PNG_INTERLACE_ADAM7_PASSES in png.h
+
+libpng can fill out those images or it can give them to you "as is".
+It is almost always better to have libpng handle the interlacing for you.
+If you want the images filled out, there are two ways to do that.  The one
+mentioned in the PNG specification is to expand each pixel to cover
+those pixels that have not been read yet (the "rectangle" method).
+This results in a blocky image for the first pass, which gradually
+smooths out as more pixels are read.  The other method is the "sparkle"
+method, where pixels are drawn only in their final locations, with the
+rest of the image remaining whatever colors they were initialized to
+before the start of the read.  The first method usually looks better,
+but tends to be slower, as there are more pixels to put in the rows.
+
+If, as is likely, you want libpng to expand the images, call this before
+calling png_start_read_image() or png_read_update_info():
+
+    if (interlace_type == PNG_INTERLACE_ADAM7)
+       number_of_passes
+           = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed.  Currently, this is seven,
+but may change if another interlace type is added.  This function can be
+called even if the file is not interlaced, where it will return one pass.
+You then need to read the whole image 'number_of_passes' times.  Each time
+will distribute the pixels from the current pass to the correct place in
+the output image, so you need to supply the same rows to png_read_rows in
+each pass.
+
+If you are not going to display the image after each pass, but are
+going to wait until the entire image is read in, use the sparkle
+effect.  This effect is faster and the end result of either method
+is exactly the same.  If you are planning on displaying the image
+after each pass, the "rectangle" effect is generally considered the
+better looking one.
+
+If you only want the "sparkle" effect, just call png_read_row() or
+png_read_rows() as
+normal, with the third parameter NULL.  Make sure you make pass over
+the image number_of_passes times, and you don't change the data in the
+rows between calls.  You can change the locations of the data, just
+not the data.  Each pass only writes the pixels appropriate for that
+pass, and assumes the data from previous passes is still valid.
+
+    png_read_rows(png_ptr, row_pointers, NULL,
+        number_of_rows);
+    or
+    png_read_row(png_ptr, row_pointers, NULL);
+
+If you only want the first effect (the rectangles), do the same as
+before except pass the row buffer in the third parameter, and leave
+the second parameter NULL.
+
+    png_read_rows(png_ptr, NULL, row_pointers,
+        number_of_rows);
+    or
+    png_read_row(png_ptr, NULL, row_pointers);
+
+If you don't want libpng to handle the interlacing details, just call
+png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
+Each of the images is a valid image by itself; however, you will almost
+certainly need to distribute the pixels from each sub-image to the
+correct place.  This is where everything gets very tricky.
+
+If you want to retrieve the separate images you must pass the correct
+number of rows to each successive call of png_read_rows().  The calculation
+gets pretty complicated for small images, where some sub-images may
+not even exist because either their width or height ends up zero.
+libpng provides two macros to help you in 1.5 and later versions:
+
+   png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
+   png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
+
+Respectively these tell you the width and height of the sub-image
+corresponding to the numbered pass.  'pass' is in in the range 0 to 6 -
+this can be confusing because the specification refers to the same passes
+as 1 to 7!  Be careful, you must check both the width and height before
+calling png_read_rows() and not call it for that pass if either is zero.
+
+You can, of course, read each sub-image row by row.  If you want to
+produce optimal code to make a pixel-by-pixel transformation of an
+interlaced image this is the best approach; read each row of each pass,
+transform it, and write it out to a new interlaced image.
+
+If you want to de-interlace the image yourself libpng provides further
+macros to help that tell you where to place the pixels in the output image.
+Because the interlacing scheme is rectangular - sub-image pixels are always
+arranged on a rectangular grid - all you need to know for each pass is the
+starting column and row in the output image of the first pixel plus the
+spacing between each pixel.  As of libpng 1.5 there are four macros to
+retrieve this information:
+
+   png_uint_32 x = PNG_PASS_START_COL(pass);
+   png_uint_32 y = PNG_PASS_START_ROW(pass);
+   png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
+   png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
+
+These allow you to write the obvious loop:
+
+   png_uint_32 input_y = 0;
+   png_uint_32 output_y = PNG_PASS_START_ROW(pass);
+
+   while (output_y < output_image_height)
+   {
+      png_uint_32 input_x = 0;
+      png_uint_32 output_x = PNG_PASS_START_COL(pass);
+
+      while (output_x < output_image_width)
+      {
+         image[output_y][output_x] =
+             subimage[pass][input_y][input_x++];
+
+         output_x += xStep;
+      }
+
+      ++input_y;
+      output_y += yStep;
+   }
+
+Notice that the steps between successive output rows and columns are
+returned as shifts.  This is possible because the pixels in the subimages
+are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
+image.  In practice you may need to directly calculate the output coordinate
+given an input coordinate.  libpng provides two further macros for this
+purpose:
+
+   png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
+   png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
+
+Finally a pair of macros are provided to tell you if a particular image
+row or column appears in a given pass:
+
+   int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
+   int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
+
+Bear in mind that you will probably also need to check the width and height
+of the pass in addition to the above to be sure the pass even exists!
+
+With any luck you are convinced by now that you don't want to do your own
+interlace handling.  In reality normally the only good reason for doing this
+is if you are processing PNG files on a pixel-by-pixel basis and don't want
+to load the whole file into memory when it is interlaced.
+
+libpng includes a test program, pngvalid, that illustrates reading and
+writing of interlaced images.  If you can't get interlacing to work in your
+code and don't want to leave it to libpng (the recommended approach), see
+how pngvalid.c does it.
+
+Finishing a sequential read
+
+After you are finished reading the image through the
+low-level interface, you can finish reading the file.
+
+If you want to use a different crc action for handling CRC errors in
+chunks after the image data, you can call png_set_crc_action()
+again at this point.
+
+If you are interested in comments or time, which may be stored either
+before or after the image data, you should pass the separate png_info
+struct if you want to keep the comments from before and after the image
+separate.
+
+    png_infop end_info = png_create_info_struct(png_ptr);
+
+    if (!end_info)
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+           (png_infopp)NULL);
+       return ERROR;
+    }
+
+   png_read_end(png_ptr, end_info);
+
+If you are not interested, you should still call png_read_end()
+but you can pass NULL, avoiding the need to create an end_info structure.
+If you do this, libpng will not process any chunks after IDAT other than
+skipping over them and perhaps (depending on whether you have called
+png_set_crc_action) checking their CRCs while looking for the IEND chunk.
+
+   png_read_end(png_ptr, (png_infop)NULL);
+
+If you don't call png_read_end(), then your file pointer will be
+left pointing to the first chunk after the last IDAT, which is probably
+not what you want if you expect to read something beyond the end of
+the PNG datastream.
+
+When you are done, you can free all memory allocated by libpng like this:
+
+   png_destroy_read_struct(&png_ptr, &info_ptr,
+       &end_info);
+
+or, if you didn't create an end_info structure,
+
+   png_destroy_read_struct(&png_ptr, &info_ptr,
+       (png_infopp)NULL);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+    png_free_data(png_ptr, info_ptr, mask, seq)
+
+    mask - identifies data to be freed, a mask
+           containing the bitwise OR of one or
+           more of
+             PNG_FREE_PLTE, PNG_FREE_TRNS,
+             PNG_FREE_HIST, PNG_FREE_ICCP,
+             PNG_FREE_PCAL, PNG_FREE_ROWS,
+             PNG_FREE_SCAL, PNG_FREE_SPLT,
+             PNG_FREE_TEXT, PNG_FREE_UNKN,
+           or simply PNG_FREE_ALL
+
+    seq  - sequence number of item to be freed
+           (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng,  and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed.  If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+The default behavior is only to free data that was allocated internally
+by libpng.  This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+    png_data_freer(png_ptr, info_ptr, freer, mask)
+
+    freer  - one of
+               PNG_DESTROY_WILL_FREE_DATA
+               PNG_SET_WILL_FREE_DATA
+               PNG_USER_WILL_FREE_DATA
+
+    mask   - which data elements are affected
+             same choices as in png_free_data()
+
+This function only affects data that has already been allocated.
+You can call this function after reading the PNG data but before calling
+any png_set_*() functions, to control whether the user or the png_set_*()
+function is responsible for freeing any existing data that might be present,
+and again after the png_set_*() functions to control whether the user
+or png_destroy_*() is supposed to free the data.  When the user assumes
+responsibility for libpng-allocated data, the application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated your row_pointers in a single block, as suggested above in
+the description of the high level read interface, you must not transfer
+responsibility for freeing it to the png_set_rows or png_read_destroy function,
+because they would also try to free the individual row_pointers[i].
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key.  Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+
+The png_free_data() function will turn off the "valid" flag for anything
+it frees.  If you need to turn the flag off for a chunk that was freed by
+your application instead of by libpng, you can use
+
+    png_set_invalid(png_ptr, info_ptr, mask);
+
+    mask - identifies the chunks to be made invalid,
+           containing the bitwise OR of one or
+           more of
+             PNG_INFO_gAMA, PNG_INFO_sBIT,
+             PNG_INFO_cHRM, PNG_INFO_PLTE,
+             PNG_INFO_tRNS, PNG_INFO_bKGD,
+             PNG_INFO_eXIf,
+             PNG_INFO_hIST, PNG_INFO_pHYs,
+             PNG_INFO_oFFs, PNG_INFO_tIME,
+             PNG_INFO_pCAL, PNG_INFO_sRGB,
+             PNG_INFO_iCCP, PNG_INFO_sPLT,
+             PNG_INFO_sCAL, PNG_INFO_IDAT
+
+For a more compact example of reading a PNG image, see the file example.c.
+
+Reading PNG files progressively
+
+The progressive reader is slightly different from the non-progressive
+reader.  Instead of calling png_read_info(), png_read_rows(), and
+png_read_end(), you make one call to png_process_data(), which calls
+callbacks when it has the info, a row, or the end of the image.  You
+set up these callbacks with png_set_progressive_read_fn().  You don't
+have to worry about the input/output functions of libpng, as you are
+giving the library the data directly in png_process_data().  I will
+assume that you have read the section on reading PNG files above,
+so I will only highlight the differences (although I will show
+all of the code).
+
+png_structp png_ptr;
+png_infop info_ptr;
+
+ /*  An example code fragment of how you would
+     initialize the progressive reader in your
+     application. */
+ int
+ initialize_png_reader()
+ {
+    png_ptr = png_create_read_struct
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+         user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+        return ERROR;
+
+    info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+    {
+       png_destroy_read_struct(&png_ptr,
+          (png_infopp)NULL, (png_infopp)NULL);
+       return ERROR;
+    }
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+          (png_infopp)NULL);
+       return ERROR;
+    }
+
+    /* This one's new.  You can provide functions
+       to be called when the header info is valid,
+       when each row is completed, and when the image
+       is finished.  If you aren't using all functions,
+       you can specify NULL parameters.  Even when all
+       three functions are NULL, you need to call
+       png_set_progressive_read_fn().  You can use
+       any struct as the user_ptr (cast to a void pointer
+       for the function call), and retrieve the pointer
+       from inside the callbacks using the function
+
+          png_get_progressive_ptr(png_ptr);
+
+       which will return a void pointer, which you have
+       to cast appropriately.
+     */
+    png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
+        info_callback, row_callback, end_callback);
+
+    return 0;
+ }
+
+ /* A code fragment that you call as you receive blocks
+   of data */
+ int
+ process_data(png_bytep buffer, png_uint_32 length)
+ {
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+           (png_infopp)NULL);
+       return ERROR;
+    }
+
+    /* This one's new also.  Simply give it a chunk
+       of data from the file stream (in order, of
+       course).  On machines with segmented memory
+       models machines, don't give it any more than
+       64K.  The library seems to run fine with sizes
+       of 4K. Although you can give it much less if
+       necessary (I assume you can give it chunks of
+       1 byte, I haven't tried less than 256 bytes
+       yet).  When this function returns, you may
+       want to display any rows that were generated
+       in the row callback if you don't already do
+       so there.
+     */
+    png_process_data(png_ptr, info_ptr, buffer, length);
+
+    /* At this point you can call png_process_data_skip if
+       you want to handle data the library will skip yourself;
+       it simply returns the number of bytes to skip (and stops
+       libpng skipping that number of bytes on the next
+       png_process_data call).
+    return 0;
+ }
+
+ /* This function is called (as set by
+    png_set_progressive_read_fn() above) when enough data
+    has been supplied so all of the header has been
+    read.
+ */
+ void
+ info_callback(png_structp png_ptr, png_infop info)
+ {
+    /* Do any setup here, including setting any of
+       the transformations mentioned in the Reading
+       PNG files section.  For now, you _must_ call
+       either png_start_read_image() or
+       png_read_update_info() after all the
+       transformations are set (even if you don't set
+       any).  You may start getting rows before
+       png_process_data() returns, so this is your
+       last chance to prepare for that.
+
+       This is where you turn on interlace handling,
+       assuming you don't want to do it yourself.
+
+       If you need to you can stop the processing of
+       your original input data at this point by calling
+       png_process_data_pause.  This returns the number
+       of unprocessed bytes from the last png_process_data
+       call - it is up to you to ensure that the next call
+       sees these bytes again.  If you don't want to bother
+       with this you can get libpng to cache the unread
+       bytes by setting the 'save' parameter (see png.h) but
+       then libpng will have to copy the data internally.
+     */
+ }
+
+ /* This function is called when each row of image
+    data is complete */
+ void
+ row_callback(png_structp png_ptr, png_bytep new_row,
+    png_uint_32 row_num, int pass)
+ {
+    /* If the image is interlaced, and you turned
+       on the interlace handler, this function will
+       be called for every row in every pass.  Some
+       of these rows will not be changed from the
+       previous pass.  When the row is not changed,
+       the new_row variable will be NULL.  The rows
+       and passes are called in order, so you don't
+       really need the row_num and pass, but I'm
+       supplying them because it may make your life
+       easier.
+
+       If you did not turn on interlace handling then
+       the callback is called for each row of each
+       sub-image when the image is interlaced.  In this
+       case 'row_num' is the row in the sub-image, not
+       the row in the output image as it is in all other
+       cases.
+
+       For the non-NULL rows of interlaced images when
+       you have switched on libpng interlace handling,
+       you must call png_progressive_combine_row()
+       passing in the row and the old row.  You can
+       call this function for NULL rows (it will just
+       return) and for non-interlaced images (it just
+       does the memcpy for you) if it will make the
+       code easier.  Thus, you can just do this for
+       all cases if you switch on interlace handling;
+     */
+
+        png_progressive_combine_row(png_ptr, old_row,
+          new_row);
+
+    /* where old_row is what was displayed
+       previously for the row.  Note that the first
+       pass (pass == 0, really) will completely cover
+       the old row, so the rows do not have to be
+       initialized.  After the first pass (and only
+       for interlaced images), you will have to pass
+       the current row, and the function will combine
+       the old row and the new row.
+
+       You can also call png_process_data_pause in this
+       callback - see above.
+    */
+ }
+
+ void
+ end_callback(png_structp png_ptr, png_infop info)
+ {
+    /* This function is called after the whole image
+       has been read, including any chunks after the
+       image (up to and including the IEND).  You
+       will usually have the same info chunk as you
+       had in the header, although some data may have
+       been added to the comments and time fields.
+
+       Most people won't do much here, perhaps setting
+       a flag that marks the image as finished.
+     */
+ }
+
+
+
+IV. Writing
+
+Much of this is very similar to reading.  However, everything of
+importance is repeated here, so you won't have to constantly look
+back up in the reading section to understand writing.
+
+Setup
+
+You will want to do the I/O initialization before you get into libpng,
+so if it doesn't work, you don't have anything to undo. If you are not
+using the standard I/O functions, you will need to replace them with
+custom writing functions.  See the discussion under Customizing libpng.
+
+    FILE *fp = fopen(file_name, "wb");
+
+    if (!fp)
+       return ERROR;
+
+Next, png_struct and png_info need to be allocated and initialized.
+As these can be both relatively large, you may not want to store these
+on the stack, unless you have stack space to spare.  Of course, you
+will want to check if they return NULL.  If you are also reading,
+you won't want to name your read structure and your write structure
+both "png_ptr"; you can call them anything you like, such as
+"read_ptr" and "write_ptr".  Look at pngtest.c, for example.
+
+    png_structp png_ptr = png_create_write_struct
+       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+       return ERROR;
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr)
+    {
+       png_destroy_write_struct(&png_ptr,
+           (png_infopp)NULL);
+       return ERROR;
+    }
+
+If you want to use your own memory allocation routines,
+define PNG_USER_MEM_SUPPORTED and use
+png_create_write_struct_2() instead of png_create_write_struct():
+
+    png_structp png_ptr = png_create_write_struct_2
+       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn, (png_voidp)
+        user_mem_ptr, user_malloc_fn, user_free_fn);
+
+After you have these structures, you will need to set up the
+error handling.  When libpng encounters an error, it expects to
+longjmp() back to your routine.  Therefore, you will need to call
+setjmp() and pass the png_jmpbuf(png_ptr).  If you
+write the file from different routines, you will need to update
+the png_jmpbuf(png_ptr) every time you enter a new routine that will
+call a png_*() function.  See your documentation of setjmp/longjmp
+for your compiler for more information on setjmp/longjmp.  See
+the discussion on libpng error handling in the Customizing Libpng
+section below for more information on the libpng error handling.
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+       fclose(fp);
+       return ERROR;
+    }
+    ...
+    return;
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+   png_set_check_for_invalid_index(png_ptr, 0);
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are written as-is by the encoder, resulting in an
+invalid PNG datastream as output.  In this case the application is
+responsible for ensuring that the pixel indexes are in range when it writes
+a PLTE chunk with fewer entries than the bit depth would allow.
+
+Now you need to set up the output code.  The default for libpng is to
+use the C function fwrite().  If you use this, you will need to pass a
+valid FILE * in the function png_init_io().  Be sure that the file is
+opened in binary mode.  Again, if you wish to handle writing data in
+another way, see the discussion on libpng I/O handling in the Customizing
+Libpng section below.
+
+    png_init_io(png_ptr, fp);
+
+If you are embedding your PNG into a datastream such as MNG, and don't
+want libpng to write the 8-byte signature, or if you have already
+written the signature in your application, use
+
+    png_set_sig_bytes(png_ptr, 8);
+
+to inform libpng that it should not write a signature.
+
+Write callbacks
+
+At this point, you can set up a callback function that will be
+called after each row has been written, which you can use to control
+a progress meter or the like.  It's demonstrated in pngtest.c.
+You must supply a function
+
+    void write_row_callback(png_structp png_ptr, png_uint_32 row,
+       int pass);
+    {
+      /* put your code here */
+    }
+
+(You can give it another name that you like instead of "write_row_callback")
+
+To inform libpng about your function, use
+
+    png_set_write_status_fn(png_ptr, write_row_callback);
+
+When this function is called the row has already been completely processed and
+it has also been written out.  The 'row' and 'pass' refer to the next row to be
+handled.  For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0.  For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes.  Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass-1', if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+You now have the option of modifying how the compression library will
+run.  The following functions are mainly for testing, but may be useful
+in some cases, like if you need to write PNG files extremely fast and
+are willing to give up some compression, or if you want to get the
+maximum possible compression at the expense of slower writing.  If you
+have no special needs in this area, let the library do what it wants by
+not calling this function at all, as it has been tuned to deliver a good
+speed/compression ratio. The second parameter to png_set_filter() is
+the filter method, for which the only valid values are 0 (as of the
+July 1999 PNG specification, version 1.2) or 64 (if you are writing
+a PNG datastream that is to be embedded in a MNG datastream).  The third
+parameter is a flag that indicates which filter type(s) are to be tested
+for each scanline.  See the PNG specification for details on the specific
+filter types.
+
+
+    /* turn on or off filtering, and/or choose
+       specific filters.  You can use either a single
+       PNG_FILTER_VALUE_NAME or the bitwise OR of one
+       or more PNG_FILTER_NAME masks.
+     */
+    png_set_filter(png_ptr, 0,
+       PNG_FILTER_NONE  | PNG_FILTER_VALUE_NONE |
+       PNG_FILTER_SUB   | PNG_FILTER_VALUE_SUB  |
+       PNG_FILTER_UP    | PNG_FILTER_VALUE_UP   |
+       PNG_FILTER_AVG   | PNG_FILTER_VALUE_AVG  |
+       PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
+       PNG_ALL_FILTERS  | PNG_FAST_FILTERS);
+
+If an application wants to start and stop using particular filters during
+compression, it should start out with all of the filters (to ensure that
+the previous row of pixels will be stored in case it's needed later),
+and then add and remove them after the start of compression.
+
+If you are writing a PNG datastream that is to be embedded in a MNG
+datastream, the second parameter can be either 0 or 64.
+
+The png_set_compression_*() functions interface to the zlib compression
+library, and should mostly be ignored unless you really know what you are
+doing.  The only generally useful call is png_set_compression_level()
+which changes how much time zlib spends on trying to compress the image
+data.  See the Compression Library (zlib.h and algorithm.txt, distributed
+with zlib) for details on the compression levels.
+
+    #include zlib.h
+
+    /* Set the zlib compression level */
+    png_set_compression_level(png_ptr,
+        Z_BEST_COMPRESSION);
+
+    /* Set other zlib parameters for compressing IDAT */
+    png_set_compression_mem_level(png_ptr, 8);
+    png_set_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_compression_window_bits(png_ptr, 15);
+    png_set_compression_method(png_ptr, 8);
+    png_set_compression_buffer_size(png_ptr, 8192)
+
+    /* Set zlib parameters for text compression
+     * If you don't call these, the parameters
+     * fall back on those defined for IDAT chunks
+     */
+    png_set_text_compression_mem_level(png_ptr, 8);
+    png_set_text_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_text_compression_window_bits(png_ptr, 15);
+    png_set_text_compression_method(png_ptr, 8);
+
+Setting the contents of info for output
+
+You now need to fill in the png_info structure with all the data you
+wish to write before the actual image.  Note that the only thing you
+are allowed to write after the image is the text chunks and the time
+chunk (as of PNG Specification 1.2, anyway).  See png_write_end() and
+the latest PNG specification for more information on that.  If you
+wish to write them before the image, fill them in now, and flag that
+data as being valid.  If you want to wait until after the data, don't
+fill them until png_write_end().  For all the fields in png_info and
+their data types, see png.h.  For explanations of what the fields
+contain, see the PNG specification.
+
+Some of the more important parts of the png_info are:
+
+    png_set_IHDR(png_ptr, info_ptr, width, height,
+       bit_depth, color_type, interlace_type,
+       compression_type, filter_method)
+
+    width          - holds the width of the image
+                     in pixels (up to 2^31).
+
+    height         - holds the height of the image
+                     in pixels (up to 2^31).
+
+    bit_depth      - holds the bit depth of one of the
+                     image channels.
+                     (valid values are 1, 2, 4, 8, 16
+                     and depend also on the
+                     color_type.  See also significant
+                     bits (sBIT) below).
+
+    color_type     - describes which color/alpha
+                     channels are present.
+                     PNG_COLOR_TYPE_GRAY
+                        (bit depths 1, 2, 4, 8, 16)
+                     PNG_COLOR_TYPE_GRAY_ALPHA
+                        (bit depths 8, 16)
+                     PNG_COLOR_TYPE_PALETTE
+                        (bit depths 1, 2, 4, 8)
+                     PNG_COLOR_TYPE_RGB
+                        (bit_depths 8, 16)
+                     PNG_COLOR_TYPE_RGB_ALPHA
+                        (bit_depths 8, 16)
+
+                     PNG_COLOR_MASK_PALETTE
+                     PNG_COLOR_MASK_COLOR
+                     PNG_COLOR_MASK_ALPHA
+
+    interlace_type - PNG_INTERLACE_NONE or
+                     PNG_INTERLACE_ADAM7
+
+    compression_type - (must be
+                     PNG_COMPRESSION_TYPE_DEFAULT)
+
+    filter_method  - (must be PNG_FILTER_TYPE_DEFAULT
+                     or, if you are writing a PNG to
+                     be embedded in a MNG datastream,
+                     can also be
+                     PNG_INTRAPIXEL_DIFFERENCING)
+
+If you call png_set_IHDR(), the call must appear before any of the
+other png_set_*() functions, because they might require access to some of
+the IHDR settings.  The remaining png_set_*() functions can be called
+in any order.
+
+If you wish, you can reset the compression_type, interlace_type, or
+filter_method later by calling png_set_IHDR() again; if you do this, the
+width, height, bit_depth, and color_type must be the same in each call.
+
+    png_set_PLTE(png_ptr, info_ptr, palette,
+       num_palette);
+
+    palette        - the palette for the file
+                     (array of png_color)
+    num_palette    - number of entries in the palette
+
+
+    png_set_gAMA(png_ptr, info_ptr, file_gamma);
+    png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
+
+    file_gamma     - the gamma at which the image was
+                     created (PNG_INFO_gAMA)
+
+    int_file_gamma - 100,000 times the gamma at which
+                     the image was created
+
+    png_set_cHRM(png_ptr, info_ptr,  white_x, white_y, red_x, red_y,
+                     green_x, green_y, blue_x, blue_y)
+    png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X,
+                     green_Y, green_Z, blue_X, blue_Y, blue_Z)
+    png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y,
+                     int_red_x, int_red_y, int_green_x, int_green_y,
+                     int_blue_x, int_blue_y)
+    png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y,
+                     int_red_Z, int_green_X, int_green_Y, int_green_Z,
+                     int_blue_X, int_blue_Y, int_blue_Z)
+
+    {white,red,green,blue}_{x,y}
+                     A color space encoding specified using the chromaticities
+                     of the end points and the white point.
+
+    {red,green,blue}_{X,Y,Z}
+                     A color space encoding specified using the encoding end
+                     points - the CIE tristimulus specification of the intended
+                     color of the red, green and blue channels in the PNG RGB
+                     data.  The white point is simply the sum of the three end
+                     points.
+
+    png_set_sRGB(png_ptr, info_ptr, srgb_intent);
+
+    srgb_intent    - the rendering intent
+                     (PNG_INFO_sRGB) The presence of
+                     the sRGB chunk means that the pixel
+                     data is in the sRGB color space.
+                     This chunk also implies specific
+                     values of gAMA and cHRM.  Rendering
+                     intent is the CSS-1 property that
+                     has been defined by the International
+                     Color Consortium
+                     (http://www.color.org).
+                     It can be one of
+                     PNG_sRGB_INTENT_SATURATION,
+                     PNG_sRGB_INTENT_PERCEPTUAL,
+                     PNG_sRGB_INTENT_ABSOLUTE, or
+                     PNG_sRGB_INTENT_RELATIVE.
+
+
+    png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
+       srgb_intent);
+
+    srgb_intent    - the rendering intent
+                     (PNG_INFO_sRGB) The presence of the
+                     sRGB chunk means that the pixel
+                     data is in the sRGB color space.
+                     This function also causes gAMA and
+                     cHRM chunks with the specific values
+                     that are consistent with sRGB to be
+                     written.
+
+    png_set_iCCP(png_ptr, info_ptr, name, compression_type,
+                       profile, proflen);
+
+    name             - The profile name.
+
+    compression_type - The compression type; always
+                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+                       You may give NULL to this argument to
+                       ignore it.
+
+    profile          - International Color Consortium color
+                       profile data. May contain NULs.
+
+    proflen          - length of profile data in bytes.
+
+    png_set_sBIT(png_ptr, info_ptr, sig_bit);
+
+    sig_bit        - the number of significant bits for
+                     (PNG_INFO_sBIT) each of the gray, red,
+                     green, and blue channels, whichever are
+                     appropriate for the given color type
+                     (png_color_16)
+
+    png_set_tRNS(png_ptr, info_ptr, trans_alpha,
+       num_trans, trans_color);
+
+    trans_alpha    - array of alpha (transparency)
+                     entries for palette (PNG_INFO_tRNS)
+
+    num_trans      - number of transparent entries
+                     (PNG_INFO_tRNS)
+
+    trans_color    - graylevel or color sample values
+                     (in order red, green, blue) of the
+                     single transparent color for
+                     non-paletted images (PNG_INFO_tRNS)
+
+    png_set_eXIf_1(png_ptr, info_ptr, num_exif, exif);
+
+    exif           - Exif profile (array of
+                     png_byte) (PNG_INFO_eXIf)
+
+    png_set_hIST(png_ptr, info_ptr, hist);
+
+    hist           - histogram of palette (array of
+                     png_uint_16) (PNG_INFO_hIST)
+
+    png_set_tIME(png_ptr, info_ptr, mod_time);
+
+    mod_time       - time image was last modified
+                     (PNG_VALID_tIME)
+
+    png_set_bKGD(png_ptr, info_ptr, background);
+
+    background     - background color (of type
+                     png_color_16p) (PNG_VALID_bKGD)
+
+    png_set_text(png_ptr, info_ptr, text_ptr, num_text);
+
+    text_ptr       - array of png_text holding image
+                     comments
+
+    text_ptr[i].compression - type of compression used
+                 on "text" PNG_TEXT_COMPRESSION_NONE
+                           PNG_TEXT_COMPRESSION_zTXt
+                           PNG_ITXT_COMPRESSION_NONE
+                           PNG_ITXT_COMPRESSION_zTXt
+    text_ptr[i].key   - keyword for comment.  Must contain
+                 1-79 characters.
+    text_ptr[i].text  - text comments for current
+                         keyword.  Can be NULL or empty.
+    text_ptr[i].text_length - length of text string,
+                 after decompression, 0 for iTXt
+    text_ptr[i].itxt_length - length of itxt string,
+                 after decompression, 0 for tEXt/zTXt
+    text_ptr[i].lang  - language of comment (NULL or
+                         empty for unknown).
+    text_ptr[i].translated_keyword  - keyword in UTF-8 (NULL
+                         or empty for unknown).
+
+    Note that the itxt_length, lang, and lang_key
+    members of the text_ptr structure only exist when the
+    library is built with iTXt chunk support.  Prior to
+    libpng-1.4.0 the library was built by default without
+    iTXt support. Also note that when iTXt is supported,
+    they contain NULL pointers when the "compression"
+    field contains PNG_TEXT_COMPRESSION_NONE or
+    PNG_TEXT_COMPRESSION_zTXt.
+
+    num_text       - number of comments
+
+    png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
+       num_spalettes);
+
+    palette_ptr    - array of png_sPLT_struct structures
+                     to be added to the list of palettes
+                     in the info structure.
+    num_spalettes  - number of palette structures to be
+                     added.
+
+    png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
+        unit_type);
+
+    offset_x  - positive offset from the left
+                     edge of the screen
+
+    offset_y  - positive offset from the top
+                     edge of the screen
+
+    unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+    png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
+        unit_type);
+
+    res_x       - pixels/unit physical resolution
+                  in x direction
+
+    res_y       - pixels/unit physical resolution
+                  in y direction
+
+    unit_type   - PNG_RESOLUTION_UNKNOWN,
+                  PNG_RESOLUTION_METER
+
+    png_set_sCAL(png_ptr, info_ptr, unit, width, height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+
+    height      - height of a pixel in physical scale units
+                  (width and height are doubles)
+
+    png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+                  expressed as a string
+
+    height      - height of a pixel in physical scale units
+                 (width and height are strings like "2.54")
+
+    png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
+       num_unknowns)
+
+    unknowns          - array of png_unknown_chunk
+                        structures holding unknown chunks
+    unknowns[i].name  - name of unknown chunk
+    unknowns[i].data  - data of unknown chunk
+    unknowns[i].size  - size of unknown chunk's data
+    unknowns[i].location - position to write chunk in file
+                           0: do not write chunk
+                           PNG_HAVE_IHDR: before PLTE
+                           PNG_HAVE_PLTE: before IDAT
+                           PNG_AFTER_IDAT: after IDAT
+
+The "location" member is set automatically according to
+what part of the output file has already been written.
+You can change its value after calling png_set_unknown_chunks()
+as demonstrated in pngtest.c.  Within each of the "locations",
+the chunks are sequenced according to their position in the
+structure (that is, the value of "i", which is the order in which
+the chunk was either read from the input file or defined with
+png_set_unknown_chunks).
+
+A quick word about text and num_text.  text is an array of png_text
+structures.  num_text is the number of valid structures in the array.
+Each png_text structure holds a language code, a keyword, a text value,
+and a compression type.
+
+The compression types have the same valid numbers as the compression
+types of the image data.  Currently, the only valid number is zero.
+However, you can store text either compressed or uncompressed, unlike
+images, which always have to be compressed.  So if you don't want the
+text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
+Because tEXt and zTXt chunks don't have a language field, if you
+specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
+any language code or translated keyword will not be written out.
+
+Until text gets around a few hundred bytes, it is not worth compressing it.
+After the text has been written out to the file, the compression type
+is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
+so that it isn't written out again at the end (in case you are calling
+png_write_end() with the same struct).
+
+The keywords that are given in the PNG Specification are:
+
+    Title            Short (one line) title or
+                     caption for image
+
+    Author           Name of image's creator
+
+    Description      Description of image (possibly long)
+
+    Copyright        Copyright notice
+
+    Creation Time    Time of original image creation
+                     (usually RFC 1123 format, see below)
+
+    Software         Software used to create the image
+
+    Disclaimer       Legal disclaimer
+
+    Warning          Warning of nature of content
+
+    Source           Device used to create the image
+
+    Comment          Miscellaneous comment; conversion
+                     from other image format
+
+The keyword-text pairs work like this.  Keywords should be short
+simple descriptions of what the comment is about.  Some typical
+keywords are found in the PNG specification, as is some recommendations
+on keywords.  You can repeat keywords in a file.  You can even write
+some text before the image and some after.  For example, you may want
+to put a description of the image before the image, but leave the
+disclaimer until after, so viewers working over modem connections
+don't have to wait for the disclaimer to go over the modem before
+they start seeing the image.  Finally, keywords should be full
+words, not abbreviations.  Keywords and text are in the ISO 8859-1
+(Latin-1) character set (a superset of regular ASCII) and can not
+contain NUL characters, and should not contain control or other
+unprintable characters.  To make the comments widely readable, stick
+with basic ASCII, and avoid machine specific character set extensions
+like the IBM-PC character set.  The keyword must be present, but
+you can leave off the text string on non-compressed pairs.
+Compressed pairs must have a text string, as only the text string
+is compressed anyway, so the compression would be meaningless.
+
+PNG supports modification time via the png_time structure.  Two
+conversion routines are provided, png_convert_from_time_t() for
+time_t and png_convert_from_struct_tm() for struct tm.  The
+time_t routine uses gmtime().  You don't have to use either of
+these, but if you wish to fill in the png_time structure directly,
+you should provide the time in universal time (GMT) if possible
+instead of your local time.  Note that the year number is the full
+year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
+that months start with 1.
+
+If you want to store the time of the original image creation, you should
+use a plain tEXt chunk with the "Creation Time" keyword.  This is
+necessary because the "creation time" of a PNG image is somewhat vague,
+depending on whether you mean the PNG file, the time the image was
+created in a non-PNG format, a still photo from which the image was
+scanned, or possibly the subject matter itself.  In order to facilitate
+machine-readable dates, it is recommended that the "Creation Time"
+tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
+although this isn't a requirement.  Unlike the tIME chunk, the
+"Creation Time" tEXt chunk is not expected to be automatically changed
+by the software.  To facilitate the use of RFC 1123 dates, a function
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
+convert from PNG time to an RFC 1123 format string.  The caller must provide
+a writeable buffer of at least 29 bytes.
+
+Writing unknown chunks
+
+You can use the png_set_unknown_chunks function to queue up private chunks
+for writing.  You give it a chunk name, location, raw data, and a size.  You
+also must use png_set_keep_unknown_chunks() to ensure that libpng will
+handle them.  That's all there is to it.  The chunks will be written by the
+next following png_write_info_before_PLTE, png_write_info, or png_write_end
+function, depending upon the specified location.  Any chunks previously
+read into the info structure's unknown-chunk list will also be written out
+in a sequence that satisfies the PNG specification's ordering rules.
+
+Here is an example of writing two private chunks, prVt and miNE:
+
+    #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+    /* Set unknown chunk data */
+    png_unknown_chunk unk_chunk[2];
+    strcpy((char *) unk_chunk[0].name, "prVt";
+    unk_chunk[0].data = (unsigned char *) "PRIVATE DATA";
+    unk_chunk[0].size = strlen(unk_chunk[0].data)+1;
+    unk_chunk[0].location = PNG_HAVE_IHDR;
+    strcpy((char *) unk_chunk[1].name, "miNE";
+    unk_chunk[1].data = (unsigned char *) "MY CHUNK DATA";
+    unk_chunk[1].size = strlen(unk_chunk[0].data)+1;
+    unk_chunk[1].location = PNG_AFTER_IDAT;
+    png_set_unknown_chunks(write_ptr, write_info_ptr,
+        unk_chunk, 2);
+    /* Needed because miNE is not safe-to-copy */
+    png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
+       (png_bytep) "miNE", 1);
+    # if PNG_LIBPNG_VER < 10600
+      /* Deal with unknown chunk location bug in 1.5.x and earlier */
+      png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
+      png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
+    # endif
+    # if PNG_LIBPNG_VER < 10500
+      /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
+       * one before IDAT and another after IDAT, so don't use it; only use
+       * PNG_HAVE_IHDR location.  This call resets the location previously
+       * set by assignment and png_set_unknown_chunk_location() for chunk 1.
+       */
+      png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
+    # endif
+    #endif
+
+The high-level write interface
+
+At this point there are two ways to proceed; through the high-level
+write interface, or through a sequence of low-level write operations.
+You can use the high-level interface if your image data is present
+in the info structure.  All defined output
+transformations are permitted, enabled by the following masks.
+
+    PNG_TRANSFORM_IDENTITY      No transformation
+    PNG_TRANSFORM_PACKING       Pack 1, 2 and 4-bit samples
+    PNG_TRANSFORM_PACKSWAP      Change order of packed
+                                pixels to LSB first
+    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
+    PNG_TRANSFORM_SHIFT         Normalize pixels to the
+                                sBIT depth
+    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
+                                to BGRA
+    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
+                                to AG
+    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
+                                to transparency
+    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
+    PNG_TRANSFORM_STRIP_FILLER        Strip out filler
+                                      bytes (deprecated).
+    PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
+                                      filler bytes
+    PNG_TRANSFORM_STRIP_FILLER_AFTER  Strip out trailing
+                                      filler bytes
+
+If you have valid image data in the info structure (you can use
+png_set_rows() to put image data in the info structure), simply do this:
+
+    png_write_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some set of
+transformation flags.  This call is equivalent to png_write_info(),
+followed the set of transformations indicated by the transform mask,
+then png_write_image(), and finally png_write_end().
+
+(The final parameter of this call is not yet used.  Someday it might point
+to transformation parameters required by some future output transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_write_png().
+
+The low-level write interface
+
+If you are going the low-level route instead, you are now ready to
+write all the file information up to the actual image data.  You do
+this with a call to png_write_info().
+
+    png_write_info(png_ptr, info_ptr);
+
+Note that there is one transformation you may need to do before
+png_write_info().  In PNG files, the alpha channel in an image is the
+level of opacity.  If your data is supplied as a level of transparency,
+you can invert the alpha channel before you write it, so that 0 is
+fully transparent and 255 (in 8-bit or paletted images) or 65535
+(in 16-bit images) is fully opaque, with
+
+    png_set_invert_alpha(png_ptr);
+
+This must appear before png_write_info() instead of later with the
+other transformations because in the case of paletted images the tRNS
+chunk data has to be inverted before the tRNS chunk is written.  If
+your image is not a paletted image, the tRNS data (which in such cases
+represents a single color to be rendered as transparent) won't need to
+be changed, and you can safely do this transformation after your
+png_write_info() call.
+
+If you need to write a private chunk that you want to appear before
+the PLTE chunk when PLTE is present, you can write the PNG info in
+two steps, and insert code to write your own chunk between them:
+
+    png_write_info_before_PLTE(png_ptr, info_ptr);
+    png_set_unknown_chunks(png_ptr, info_ptr, ...);
+    png_write_info(png_ptr, info_ptr);
+
+After you've written the file information, you can set up the library
+to handle any special transformations of the image data.  The various
+ways to transform the data will be described in the order that they
+should occur.  This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths.  Even though each transformation
+checks to see if it has data that it can do something with, you should
+make sure to only enable a transformation if it will be valid for the
+data.  For example, don't swap red and blue on grayscale data.
+
+PNG files store RGB pixels packed into 3 or 6 bytes.  This code tells
+the library to strip input data that has 4 or 8 bytes per pixel down
+to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
+bytes per pixel).
+
+    png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
+PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
+is stored XRGB or RGBX.
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit files.
+If the data is supplied at 1 pixel per byte, use this code, which will
+correctly pack the pixels into a single byte:
+
+    png_set_packing(png_ptr);
+
+PNG files reduce possible bit depths to 1, 2, 4, 8, and 16.  If your
+data is of another bit depth, you can write an sBIT chunk into the
+file so that decoders can recover the original data if desired.
+
+    /* Set the true bit depth of the image data */
+    if (color_type & PNG_COLOR_MASK_COLOR)
+    {
+       sig_bit.red = true_bit_depth;
+       sig_bit.green = true_bit_depth;
+       sig_bit.blue = true_bit_depth;
+    }
+
+    else
+    {
+       sig_bit.gray = true_bit_depth;
+    }
+
+    if (color_type & PNG_COLOR_MASK_ALPHA)
+    {
+       sig_bit.alpha = true_bit_depth;
+    }
+
+    png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+If the data is stored in the row buffer in a bit depth other than
+one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
+this will scale the values to appear to be the correct bit depth as
+is required by PNG.
+
+    png_set_shift(png_ptr, &sig_bit);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first).  This code would be used if they are
+supplied the other way (little-endian, i.e. least significant bits
+first, the way PCs store them):
+
+    if (bit_depth > 8)
+       png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+    if (bit_depth < 8)
+       png_set_packswap(png_ptr);
+
+PNG files store 3 color pixels in red, green, blue order.  This code
+would be used if they are supplied as blue, green, red:
+
+    png_set_bgr(png_ptr);
+
+PNG files describe monochrome as black being zero and white being
+one. This code would be used if the pixels are supplied with this reversed
+(black being one and white being zero):
+
+    png_set_invert_mono(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs.  This is done by setting a callback
+with
+
+    png_set_write_user_transform_fn(png_ptr,
+       write_transform_fn);
+
+You must supply the function
+
+    void write_transform_fn(png_structp png_ptr, png_row_infop
+       row_info, png_bytep data)
+
+See pngtest.c for a working example.  Your function will be called
+before any of the other transformations are processed.  If supported
+libpng also supplies an information routine that may be called from
+your callback:
+
+   png_get_current_row_number(png_ptr);
+   png_get_current_pass_number(png_ptr);
+
+This returns the current row passed to the transform.  With interlaced
+images the value returned is the row in the input sub-image image.  Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function.
+
+    png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
+
+The user_channels and user_depth parameters of this function are ignored
+when writing; you can set them to zero as shown.
+
+You can retrieve the pointer via the function png_get_user_transform_ptr().
+For example:
+
+    voidp write_user_transform_ptr =
+       png_get_user_transform_ptr(png_ptr);
+
+It is possible to have libpng flush any pending output, either manually,
+or automatically after a certain number of lines have been written.  To
+flush the output stream a single time call:
+
+    png_write_flush(png_ptr);
+
+and to have libpng flush the output stream periodically after a certain
+number of scanlines have been written, call:
+
+    png_set_flush(png_ptr, nrows);
+
+Note that the distance between rows is from the last time png_write_flush()
+was called, or the first row of the image if it has never been called.
+So if you write 50 lines, and then png_set_flush 25, it will flush the
+output on the next scanline, and every 25 lines thereafter, unless
+png_write_flush() is called before 25 more lines have been written.
+If nrows is too small (less than about 10 lines for a 640 pixel wide
+RGB image) the image compression may decrease noticeably (although this
+may be acceptable for real-time applications).  Infrequent flushing will
+only degrade the compression performance by a few percent over images
+that do not use flushing.
+
+Writing the image data
+
+That's it for the transformations.  Now you can write the image data.
+The simplest way to do this is in one function call.  If you have the
+whole image in memory, you can just call png_write_image() and libpng
+will write the image.  You will need to pass in an array of pointers to
+each row.  This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() or call this function multiple
+times, or any of that other stuff necessary with png_write_rows().
+
+    png_write_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+    png_byte *row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to write the whole image at once, you can
+use png_write_rows() instead.  If the file is not interlaced,
+this is simple:
+
+    png_write_rows(png_ptr, row_pointers,
+       number_of_rows);
+
+row_pointers is the same as in the png_write_image() call.
+
+If you are just writing one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+    png_bytep row_pointer = row;
+
+    png_write_row(png_ptr, row_pointer);
+
+When the file is interlaced, things can get a good deal more complicated.
+The only currently (as of the PNG Specification version 1.2, dated July
+1999) defined interlacing scheme for PNG files is the "Adam7" interlace
+scheme, that breaks down an image into seven smaller images of varying
+size.  libpng will build these images for you, or you can do them
+yourself.  If you want to build them yourself, see the PNG specification
+for details of which pixels to write when.
+
+If you don't want libpng to handle the interlacing details, just
+use png_set_interlace_handling() and call png_write_rows() the
+correct number of times to write all the sub-images
+(png_set_interlace_handling() returns the number of sub-images.)
+
+If you want libpng to build the sub-images, call this before you start
+writing any rows:
+
+    number_of_passes = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed.  Currently, this is seven,
+but may change if another interlace type is added.
+
+Then write the complete image number_of_passes times.
+
+    png_write_rows(png_ptr, row_pointers, number_of_rows);
+
+Think carefully before you write an interlaced image.  Typically code that
+reads such images reads all the image data into memory, uncompressed, before
+doing any processing.  Only code that can display an image on the fly can
+take advantage of the interlacing and even then the image has to be exactly
+the correct size for the output device, because scaling an image requires
+adjacent pixels and these are not available until all the passes have been
+read.
+
+If you do write an interlaced image you will hardly ever need to handle
+the interlacing yourself.  Call png_set_interlace_handling() and use the
+approach described above.
+
+The only time it is conceivable that you will really need to write an
+interlaced image pass-by-pass is when you have read one pass by pass and
+made some pixel-by-pixel transformation to it, as described in the read
+code above.  In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
+to determine the size of each sub-image in turn and simply write the rows
+you obtained from the read code.
+
+Finishing a sequential write
+
+After you are finished writing the image, you should finish writing
+the file.  If you are interested in writing comments or time, you should
+pass an appropriately filled png_info pointer.  If you are not interested,
+you can pass NULL.
+
+    png_write_end(png_ptr, info_ptr);
+
+When you are done, you can free all memory used by libpng like this:
+
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+    png_free_data(png_ptr, info_ptr, mask, seq)
+
+    mask  - identifies data to be freed, a mask
+            containing the bitwise OR of one or
+            more of
+              PNG_FREE_PLTE, PNG_FREE_TRNS,
+              PNG_FREE_HIST, PNG_FREE_ICCP,
+              PNG_FREE_PCAL, PNG_FREE_ROWS,
+              PNG_FREE_SCAL, PNG_FREE_SPLT,
+              PNG_FREE_TEXT, PNG_FREE_UNKN,
+            or simply PNG_FREE_ALL
+
+    seq   - sequence number of item to be freed
+            (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user  and not by libpng,  and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed.  If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+If you allocated data such as a palette that you passed in to libpng
+with png_set_*, you must not free it until just before the call to
+png_destroy_write_struct().
+
+The default behavior is only to free data that was allocated internally
+by libpng.  This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+    png_data_freer(png_ptr, info_ptr, freer, mask)
+
+    freer  - one of
+               PNG_DESTROY_WILL_FREE_DATA
+               PNG_SET_WILL_FREE_DATA
+               PNG_USER_WILL_FREE_DATA
+
+    mask   - which data elements are affected
+             same choices as in png_free_data()
+
+For example, to transfer responsibility for some data from a read structure
+to a write structure, you could use
+
+    png_data_freer(read_ptr, read_info_ptr,
+       PNG_USER_WILL_FREE_DATA,
+       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+    png_data_freer(write_ptr, write_info_ptr,
+       PNG_DESTROY_WILL_FREE_DATA,
+       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+thereby briefly reassigning responsibility for freeing to the user but
+immediately afterwards reassigning it once more to the write_destroy
+function.  Having done this, it would then be safe to destroy the read
+structure and continue to use the PLTE, tRNS, and hIST data in the write
+structure.
+
+This function only affects data that has already been allocated.
+You can call this function before calling after the png_set_*() functions
+to control whether the user or png_destroy_*() is supposed to free the data.
+When the user assumes responsibility for libpng-allocated data, the
+application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key.  Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+For a more compact example of writing a PNG image, see the file example.c.
+
+V. Simplified API
+
+The simplified API, which became available in libpng-1.6.0, hides the details
+of both libpng and the PNG file format itself.
+It allows PNG files to be read into a very limited number of
+in-memory bitmap formats or to be written from the same formats.  If these
+formats do not accommodate your needs then you can, and should, use the more
+sophisticated APIs above - these support a wide variety of in-memory formats
+and a wide variety of sophisticated transformations to those formats as well
+as a wide variety of APIs to manipulate ancillary information.
+
+To read a PNG file using the simplified API:
+
+  1) Declare a 'png_image' structure (see below) on the stack, set the
+     version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
+     (this is REQUIRED, your program may crash if you don't do it.)
+
+  2) Call the appropriate png_image_begin_read... function.
+
+  3) Set the png_image 'format' member to the required sample format.
+
+  4) Allocate a buffer for the image and, if required, the color-map.
+
+  5) Call png_image_finish_read to read the image and, if required, the
+     color-map into your buffers.
+
+There are no restrictions on the format of the PNG input itself; all valid
+color types, bit depths, and interlace methods are acceptable, and the
+input image is transformed as necessary to the requested in-memory format
+during the png_image_finish_read() step.  The only caveat is that if you
+request a color-mapped image from a PNG that is full-color or makes
+complex use of an alpha channel the transformation is extremely lossy and the
+result may look terrible.
+
+To write a PNG file using the simplified API:
+
+  1) Declare a 'png_image' structure on the stack and memset()
+     it to all zero.
+
+  2) Initialize the members of the structure that describe the
+     image, setting the 'format' member to the format of the
+     image samples.
+
+  3) Call the appropriate png_image_write... function with a
+     pointer to the image and, if necessary, the color-map to write
+     the PNG data.
+
+png_image is a structure that describes the in-memory format of an image
+when it is being read or defines the in-memory format of an image that you
+need to write.  The "png_image" structure contains the following members:
+
+   png_controlp opaque  Initialize to NULL, free with png_image_free
+   png_uint_32  version Set to PNG_IMAGE_VERSION
+   png_uint_32  width   Image width in pixels (columns)
+   png_uint_32  height  Image height in pixels (rows)
+   png_uint_32  format  Image format as defined below
+   png_uint_32  flags   A bit mask containing informational flags
+   png_uint_32  colormap_entries; Number of entries in the color-map
+   png_uint_32  warning_or_error;
+   char         message[64];
+
+In the event of an error or warning the "warning_or_error"
+field will be set to a non-zero value and the 'message' field will contain
+a '\0' terminated string with the libpng error or warning message.  If both
+warnings and an error were encountered, only the error is recorded.  If there
+are multiple warnings, only the first one is recorded.
+
+The upper 30 bits of the "warning_or_error" value are reserved; the low two
+bits contain a two bit code such that a value more than 1 indicates a failure
+in the API just called:
+
+   0 - no warning or error
+   1 - warning
+   2 - error
+   3 - error preceded by warning
+
+The pixels (samples) of the image have one to four channels whose components
+have original values in the range 0 to 1.0:
+
+  1: A single gray or luminance channel (G).
+  2: A gray/luminance channel and an alpha channel (GA).
+  3: Three red, green, blue color channels (RGB).
+  4: Three color channels and an alpha channel (RGBA).
+
+The channels are encoded in one of two ways:
+
+  a) As a small integer, value 0..255, contained in a single byte.  For the
+alpha channel the original value is simply value/255.  For the color or
+luminance channels the value is encoded according to the sRGB specification
+and matches the 8-bit format expected by typical display devices.
+
+The color/gray channels are not scaled (pre-multiplied) by the alpha
+channel and are suitable for passing to color management software.
+
+  b) As a value in the range 0..65535, contained in a 2-byte integer, in
+the native byte order of the platform on which the application is running.
+All channels can be converted to the original value by dividing by 65535; all
+channels are linear.  Color channels use the RGB encoding (RGB end-points) of
+the sRGB specification.  This encoding is identified by the
+PNG_FORMAT_FLAG_LINEAR flag below.
+
+When the simplified API needs to convert between sRGB and linear colorspaces,
+the actual sRGB transfer curve defined in the sRGB specification (see the
+article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+approximation used elsewhere in libpng.
+
+When an alpha channel is present it is expected to denote pixel coverage
+of the color or luminance channels and is returned as an associated alpha
+channel: the color/gray channels are scaled (pre-multiplied) by the alpha
+value.
+
+The samples are either contained directly in the image data, between 1 and 8
+bytes per pixel according to the encoding, or are held in a color-map indexed
+by bytes in the image data.  In the case of a color-map the color-map entries
+are individual samples, encoded as above, and the image data has one byte per
+pixel to select the relevant sample from the color-map.
+
+PNG_FORMAT_*
+
+The #defines to be used in png_image::format.  Each #define identifies a
+particular layout of channel data and, if present, alpha values.  There are
+separate defines for each of the two component encodings.
+
+A format is built up using single bit flag values.  All combinations are
+valid.  Formats can be built up from the flag values or you can use one of
+the predefined values below.  When testing formats always use the FORMAT_FLAG
+macros to test for individual features - future versions of the library may
+add new flags.
+
+When reading or writing color-mapped images the format should be set to the
+format of the entries in the color-map then png_image_{read,write}_colormap
+called to read or write the color-map and set the format correctly for the
+image data.  Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
+
+NOTE: libpng can be built with particular features disabled. If you see
+compiler errors because the definition of one of the following flags has been
+compiled out it is because libpng does not have the required support.  It is
+possible, however, for the libpng configuration to enable the format on just
+read or just write; in that case you may see an error at run time.
+You can guard against this by checking for the definition of the
+appropriate "_SUPPORTED" macro, one of:
+
+   PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
+
+   PNG_FORMAT_FLAG_ALPHA    format with an alpha channel
+   PNG_FORMAT_FLAG_COLOR    color format: otherwise grayscale
+   PNG_FORMAT_FLAG_LINEAR   2-byte channels else 1-byte
+   PNG_FORMAT_FLAG_COLORMAP image data is color-mapped
+   PNG_FORMAT_FLAG_BGR      BGR colors, else order is RGB
+   PNG_FORMAT_FLAG_AFIRST   alpha channel comes first
+
+Supported formats are as follows.  Future versions of libpng may support more
+formats; for compatibility with older versions simply check if the format
+macro is defined using #ifdef.  These defines describe the in-memory layout
+of the components of the pixels of the image.
+
+First the single byte (sRGB) formats:
+
+   PNG_FORMAT_GRAY
+   PNG_FORMAT_GA
+   PNG_FORMAT_AG
+   PNG_FORMAT_RGB
+   PNG_FORMAT_BGR
+   PNG_FORMAT_RGBA
+   PNG_FORMAT_ARGB
+   PNG_FORMAT_BGRA
+   PNG_FORMAT_ABGR
+
+Then the linear 2-byte formats.  When naming these "Y" is used to
+indicate a luminance (gray) channel.  The component order within the pixel
+is always the same - there is no provision for swapping the order of the
+components in the linear format.  The components are 16-bit integers in
+the native byte order for your platform, and there is no provision for
+swapping the bytes to a different endian condition.
+
+   PNG_FORMAT_LINEAR_Y
+   PNG_FORMAT_LINEAR_Y_ALPHA
+   PNG_FORMAT_LINEAR_RGB
+   PNG_FORMAT_LINEAR_RGB_ALPHA
+
+With color-mapped formats the image data is one byte for each pixel. The byte
+is an index into the color-map which is formatted as above.  To obtain a
+color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
+to one of the above definitions, or you can use one of the definitions below.
+
+   PNG_FORMAT_RGB_COLORMAP
+   PNG_FORMAT_BGR_COLORMAP
+   PNG_FORMAT_RGBA_COLORMAP
+   PNG_FORMAT_ARGB_COLORMAP
+   PNG_FORMAT_BGRA_COLORMAP
+   PNG_FORMAT_ABGR_COLORMAP
+
+PNG_IMAGE macros
+
+These are convenience macros to derive information from a png_image
+structure.  The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
+actual image sample values - either the entries in the color-map or the
+pixels in the image.  The PNG_IMAGE_PIXEL_ macros return corresponding values
+for the pixels and will always return 1 for color-mapped formats.  The
+remaining macros return information about the rows in the image and the
+complete image.
+
+NOTE: All the macros that take a png_image::format parameter are compile time
+constants if the format parameter is, itself, a constant.  Therefore these
+macros can be used in array declarations and case labels where required.
+Similarly the macros are also pre-processor constants (sizeof is not used) so
+they can be used in #if tests.
+
+  PNG_IMAGE_SAMPLE_CHANNELS(fmt)
+    Returns the total number of channels in a given format: 1..4
+
+  PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)
+    Returns the size in bytes of a single component of a pixel or color-map
+    entry (as appropriate) in the image: 1 or 2.
+
+  PNG_IMAGE_SAMPLE_SIZE(fmt)
+    This is the size of the sample data for one sample.  If the image is
+    color-mapped it is the size of one color-map entry (and image pixels are
+    one byte in size), otherwise it is the size of one image pixel.
+
+  PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)
+    The maximum size of the color-map required by the format expressed in a
+    count of components.  This can be used to compile-time allocate a
+    color-map:
+
+    png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
+
+    png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
+
+    Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+    information from one of the png_image_begin_read_ APIs and dynamically
+    allocate the required memory.
+
+  PNG_IMAGE_COLORMAP_SIZE(fmt)
+   The size of the color-map required by the format; this is the size of the
+   color-map buffer passed to the png_image_{read,write}_colormap APIs. It is
+   a fixed number determined by the format so can easily be allocated on the
+   stack if necessary.
+
+Corresponding information about the pixels
+
+  PNG_IMAGE_PIXEL_CHANNELS(fmt)
+   The number of separate channels (components) in a pixel; 1 for a
+   color-mapped image.
+
+  PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
+   The size, in bytes, of each component in a pixel; 1 for a color-mapped
+   image.
+
+  PNG_IMAGE_PIXEL_SIZE(fmt)
+   The size, in bytes, of a complete pixel; 1 for a color-mapped image.
+
+Information about the whole row, or whole image
+
+  PNG_IMAGE_ROW_STRIDE(image)
+   Returns the total number of components in a single row of the image; this
+   is the minimum 'row stride', the minimum count of components between each
+   row.  For a color-mapped image this is the minimum number of bytes in a
+   row.
+
+   If you need the stride measured in bytes, row_stride_bytes is
+   PNG_IMAGE_ROW_STRIDE(image) * PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)
+   plus any padding bytes that your application might need, for example
+   to start the next row on a 4-byte boundary.
+
+  PNG_IMAGE_BUFFER_SIZE(image, row_stride)
+   Return the size, in bytes, of an image buffer given a png_image and a row
+   stride - the number of components to leave space for in each row.
+
+  PNG_IMAGE_SIZE(image)
+   Return the size, in bytes, of the image in memory given just a png_image;
+   the row stride is the minimum stride required for the image.
+
+  PNG_IMAGE_COLORMAP_SIZE(image)
+   Return the size, in bytes, of the color-map of this image.  If the image
+   format is not a color-map format this will return a size sufficient for
+   256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
+   you don't want to allocate a color-map in this case.
+
+PNG_IMAGE_FLAG_*
+
+Flags containing additional information about the image are held in
+the 'flags' field of png_image.
+
+  PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01
+    This indicates that the RGB values of the in-memory bitmap do not
+    correspond to the red, green and blue end-points defined by sRGB.
+
+  PNG_IMAGE_FLAG_FAST == 0x02
+   On write emphasise speed over compression; the resultant PNG file will be
+   larger but will be produced significantly faster, particular for large
+   images.  Do not use this option for images which will be distributed, only
+   used it when producing intermediate files that will be read back in
+   repeatedly.  For a typical 24-bit image the option will double the read
+   speed at the cost of increasing the image size by 25%, however for many
+   more compressible images the PNG file can be 10 times larger with only a
+   slight speed gain.
+
+  PNG_IMAGE_FLAG_16BIT_sRGB == 0x04
+    On read if the image is a 16-bit per component image and there is no gAMA
+    or sRGB chunk assume that the components are sRGB encoded.  Notice that
+    images output by the simplified API always have gamma information; setting
+    this flag only affects the interpretation of 16-bit images from an
+    external source.  It is recommended that the application expose this flag
+    to the user; the user can normally easily recognize the difference between
+    linear and sRGB encoding.  This flag has no effect on write - the data
+    passed to the write APIs must have the correct encoding (as defined
+    above.)
+
+    If the flag is not set (the default) input 16-bit per component data is
+    assumed to be linear.
+
+    NOTE: the flag can only be set after the png_image_begin_read_ call,
+    because that call initializes the 'flags' field.
+
+READ APIs
+
+   The png_image passed to the read APIs must have been initialized by setting
+   the png_controlp field 'opaque' to NULL (or, better, memset the whole thing.)
+
+   int png_image_begin_read_from_file( png_imagep image,
+     const char *file_name)
+
+     The named file is opened for read and the image header
+     is filled in from the PNG header in the file.
+
+   int png_image_begin_read_from_stdio (png_imagep image,
+     FILE* file)
+
+      The PNG header is read from the stdio FILE object.
+
+   int png_image_begin_read_from_memory(png_imagep image,
+      png_const_voidp memory, size_t size)
+
+      The PNG header is read from the given memory buffer.
+
+   int png_image_finish_read(png_imagep image,
+      png_colorp background, void *buffer,
+      png_int_32 row_stride, void *colormap));
+
+      Finish reading the image into the supplied buffer and
+      clean up the png_image structure.
+
+      row_stride is the step, in png_byte or png_uint_16 units
+      as appropriate, between adjacent rows.  A positive stride
+      indicates that the top-most row is first in the buffer -
+      the normal top-down arrangement.  A negative stride
+      indicates that the bottom-most row is first in the buffer.
+
+      background need only be supplied if an alpha channel must
+      be removed from a png_byte format and the removal is to be
+      done by compositing on a solid color; otherwise it may be
+      NULL and any composition will be done directly onto the
+      buffer.  The value is an sRGB color to use for the
+      background, for grayscale output the green channel is used.
+
+      For linear output removing the alpha channel is always done
+      by compositing on black.
+
+   void png_image_free(png_imagep image)
+
+      Free any data allocated by libpng in image->opaque,
+      setting the pointer to NULL.  May be called at any time
+      after the structure is initialized.
+
+When the simplified API needs to convert between sRGB and linear colorspaces,
+the actual sRGB transfer curve defined in the sRGB specification (see the
+article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+approximation used elsewhere in libpng.
+
+WRITE APIS
+
+For write you must initialize a png_image structure to describe the image to
+be written:
+
+   version: must be set to PNG_IMAGE_VERSION
+   opaque: must be initialized to NULL
+   width: image width in pixels
+   height: image height in rows
+   format: the format of the data you wish to write
+   flags: set to 0 unless one of the defined flags applies; set
+      PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images
+      where the RGB values do not correspond to the colors in sRGB.
+   colormap_entries: set to the number of entries in the color-map (0 to 256)
+
+   int png_image_write_to_file, (png_imagep image,
+      const char *file, int convert_to_8bit, const void *buffer,
+      png_int_32 row_stride, const void *colormap));
+
+      Write the image to the named file.
+
+   int png_image_write_to_memory (png_imagep image, void *memory,
+      png_alloc_size_t * PNG_RESTRICT memory_bytes,
+      int convert_to_8_bit, const void *buffer, ptrdiff_t row_stride,
+      const void *colormap));
+
+      Write the image to memory.
+
+   int png_image_write_to_stdio(png_imagep image, FILE *file,
+      int convert_to_8_bit, const void *buffer,
+      png_int_32 row_stride, const void *colormap)
+
+      Write the image to the given (FILE*).
+
+With all write APIs if image is in one of the linear formats with
+(png_uint_16) data then setting convert_to_8_bit will cause the output to be
+a (png_byte) PNG gamma encoded according to the sRGB specification, otherwise
+a 16-bit linear encoded PNG file is written.
+
+With all APIs row_stride is handled as in the read APIs - it is the spacing
+from one row to the next in component sized units (float) and if negative
+indicates a bottom-up row layout in the buffer.  If you pass zero, libpng will
+calculate the row_stride for you from the width and number of channels.
+
+Note that the write API does not support interlacing, sub-8-bit pixels,
+indexed (paletted) images, or most ancillary chunks.
+
+VI. Modifying/Customizing libpng
+
+There are two issues here.  The first is changing how libpng does
+standard things like memory allocation, input/output, and error handling.
+The second deals with more complicated things like adding new chunks,
+adding new transformations, and generally changing how libpng works.
+Both of those are compile-time issues; that is, they are generally
+determined at the time the code is written, and there is rarely a need
+to provide the user with a means of changing them.
+
+Memory allocation, input/output, and error handling
+
+All of the memory allocation, input/output, and error handling in libpng
+goes through callbacks that are user-settable.  The default routines are
+in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively.  To change
+these functions, call the appropriate png_set_*_fn() function.
+
+Memory allocation is done through the functions png_malloc(), png_calloc(),
+and png_free().  The png_malloc() and png_free() functions currently just
+call the standard C functions and png_calloc() calls png_malloc() and then
+clears the newly allocated memory to zero; note that png_calloc(png_ptr, size)
+is not the same as the calloc(number, size) function provided by stdlib.h.
+There is limited support for certain systems with segmented memory
+architectures and the types of pointers declared by png.h match this; you
+will have to use appropriate pointers in your application.  If you prefer
+to use a different method of allocating and freeing data, you can use
+png_create_read_struct_2() or png_create_write_struct_2() to register your
+own functions as described above.  These functions also provide a void
+pointer that can be retrieved via
+
+    mem_ptr=png_get_mem_ptr(png_ptr);
+
+Your replacement memory functions must have prototypes as follows:
+
+    png_voidp malloc_fn(png_structp png_ptr,
+       png_alloc_size_t size);
+
+    void free_fn(png_structp png_ptr, png_voidp ptr);
+
+Your malloc_fn() must return NULL in case of failure.  The png_malloc()
+function will normally call png_error() if it receives a NULL from the
+system memory allocator or from your replacement malloc_fn().
+
+Your free_fn() will never be called with a NULL ptr, since libpng's
+png_free() checks for NULL before calling free_fn().
+
+Input/Output in libpng is done through png_read() and png_write(),
+which currently just call fread() and fwrite().  The FILE * is stored in
+png_struct and is initialized via png_init_io().  If you wish to change
+the method of I/O, the library supplies callbacks that you can set
+through the function png_set_read_fn() and png_set_write_fn() at run
+time, instead of calling the png_init_io() function.  These functions
+also provide a void pointer that can be retrieved via the function
+png_get_io_ptr().  For example:
+
+    png_set_read_fn(png_structp read_ptr,
+        voidp read_io_ptr, png_rw_ptr read_data_fn)
+
+    png_set_write_fn(png_structp write_ptr,
+        voidp write_io_ptr, png_rw_ptr write_data_fn,
+        png_flush_ptr output_flush_fn);
+
+    voidp read_io_ptr = png_get_io_ptr(read_ptr);
+    voidp write_io_ptr = png_get_io_ptr(write_ptr);
+
+The replacement I/O functions must have prototypes as follows:
+
+    void user_read_data(png_structp png_ptr,
+        png_bytep data, size_t length);
+
+    void user_write_data(png_structp png_ptr,
+        png_bytep data, size_t length);
+
+    void user_flush_data(png_structp png_ptr);
+
+The user_read_data() function is responsible for detecting and
+handling end-of-data errors.
+
+Supplying NULL for the read, write, or flush functions sets them back
+to using the default C stream functions, which expect the io_ptr to
+point to a standard *FILE structure.  It is probably a mistake
+to use NULL for one of write_data_fn and output_flush_fn but not both
+of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
+It is an error to read from a write stream, and vice versa.
+
+Error handling in libpng is done through png_error() and png_warning().
+Errors handled through png_error() are fatal, meaning that png_error()
+should never return to its caller.  Currently, this is handled via
+setjmp() and longjmp() (unless you have compiled libpng with
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
+but you could change this to do things like exit() if you should wish,
+as long as your function does not return.
+
+On non-fatal errors, png_warning() is called
+to print a warning message, and then control returns to the calling code.
+By default png_error() and png_warning() print a message on stderr via
+fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
+(because you don't want the messages) or PNG_NO_STDIO defined (because
+fprintf() isn't available).  If you wish to change the behavior of the error
+functions, you will need to set up your own message callbacks.  These
+functions are normally supplied at the time that the png_struct is created.
+It is also possible to redirect errors and warnings to your own replacement
+functions after png_create_*_struct() has been called by calling:
+
+    png_set_error_fn(png_structp png_ptr,
+        png_voidp error_ptr, png_error_ptr error_fn,
+        png_error_ptr warning_fn);
+
+If NULL is supplied for either error_fn or warning_fn, then the libpng
+default function will be used, calling fprintf() and/or longjmp() if a
+problem is encountered.  The replacement error functions should have
+parameters as follows:
+
+    void user_error_fn(png_structp png_ptr,
+        png_const_charp error_msg);
+
+    void user_warning_fn(png_structp png_ptr,
+        png_const_charp warning_msg);
+
+Then, within your user_error_fn or user_warning_fn, you can retrieve
+the error_ptr if you need it, by calling
+
+    png_voidp error_ptr = png_get_error_ptr(png_ptr);
+
+The motivation behind using setjmp() and longjmp() is the C++ throw and
+catch exception handling methods.  This makes the code much easier to write,
+as there is no need to check every return code of every function call.
+However, there are some uncertainties about the status of local variables
+after a longjmp, so the user may want to be careful about doing anything
+after setjmp returns non-zero besides returning itself.  Consult your
+compiler documentation for more details.  For an alternative approach, you
+may wish to use the "cexcept" facility (see https://cexcept.sourceforge.io/),
+which is illustrated in pngvalid.c and in contrib/visupng.
+
+Beginning in libpng-1.4.0, the png_set_benign_errors() API became available.
+You can use this to handle certain errors (normally handled as errors)
+as warnings.
+
+    png_set_benign_errors (png_ptr, int allowed);
+
+    allowed: 0: treat png_benign_error() as an error.
+             1: treat png_benign_error() as a warning.
+
+As of libpng-1.6.0, the default condition is to treat benign errors as
+warnings while reading and as errors while writing.
+
+Custom chunks
+
+If you need to read or write custom chunks, you may need to get deeper
+into the libpng code.  The library now has mechanisms for storing
+and writing chunks of unknown type; you can even declare callbacks
+for custom chunks.  However, this may not be good enough if the
+library code itself needs to know about interactions between your
+chunk and existing `intrinsic' chunks.
+
+If you need to write a new intrinsic chunk, first read the PNG
+specification. Acquire a first level of understanding of how it works.
+Pay particular attention to the sections that describe chunk names,
+and look at how other chunks were designed, so you can do things
+similarly.  Second, check out the sections of libpng that read and
+write chunks.  Try to find a chunk that is similar to yours and use
+it as a template.  More details can be found in the comments inside
+the code.  It is best to handle private or unknown chunks in a generic method,
+via callback functions, instead of by modifying libpng functions. This
+is illustrated in pngtest.c, which uses a callback function to handle a
+private "vpAg" chunk and the new "sTER" chunk, which are both unknown to
+libpng.
+
+If you wish to write your own transformation for the data, look through
+the part of the code that does the transformations, and check out some of
+the simpler ones to get an idea of how they work.  Try to find a similar
+transformation to the one you want to add and copy off of it.  More details
+can be found in the comments inside the code itself.
+
+Configuring for gui/windowing platforms:
+
+You will need to write new error and warning functions that use the GUI
+interface, as described previously, and set them to be the error and
+warning functions at the time that png_create_*_struct() is called,
+in order to have them available during the structure initialization.
+They can be changed later via png_set_error_fn().  On some compilers,
+you may also have to change the memory allocators (png_malloc, etc.).
+
+Configuring zlib:
+
+There are special functions to configure the compression.  Perhaps the
+most useful one changes the compression level, which currently uses
+input compression values in the range 0 - 9.  The library normally
+uses the default compression level (Z_DEFAULT_COMPRESSION = 6).  Tests
+have shown that for a large majority of images, compression values in
+the range 3-6 compress nearly as well as higher levels, and do so much
+faster.  For online applications it may be desirable to have maximum speed
+(Z_BEST_SPEED = 1).  With versions of zlib after v0.99, you can also
+specify no compression (Z_NO_COMPRESSION = 0), but this would create
+files larger than just storing the raw bitmap.  You can specify the
+compression level by calling:
+
+    #include zlib.h
+    png_set_compression_level(png_ptr, level);
+
+Another useful one is to reduce the memory level used by the library.
+The memory level defaults to 8, but it can be lowered if you are
+short on memory (running DOS, for example, where you only have 640K).
+Note that the memory level does have an effect on compression; among
+other things, lower levels will result in sections of incompressible
+data being emitted in smaller stored blocks, with a correspondingly
+larger relative overhead of up to 15% in the worst case.
+
+    #include zlib.h
+    png_set_compression_mem_level(png_ptr, level);
+
+The other functions are for configuring zlib.  They are not recommended
+for normal use and may result in writing an invalid PNG file.  See
+zlib.h for more information on what these mean.
+
+    #include zlib.h
+    png_set_compression_strategy(png_ptr,
+        strategy);
+
+    png_set_compression_window_bits(png_ptr,
+        window_bits);
+
+    png_set_compression_method(png_ptr, method);
+
+This controls the size of the IDAT chunks (default 8192):
+
+    png_set_compression_buffer_size(png_ptr, size);
+
+As of libpng version 1.5.4, additional APIs became
+available to set these separately for non-IDAT
+compressed chunks such as zTXt, iTXt, and iCCP:
+
+    #include zlib.h
+    #if PNG_LIBPNG_VER >= 10504
+    png_set_text_compression_level(png_ptr, level);
+
+    png_set_text_compression_mem_level(png_ptr, level);
+
+    png_set_text_compression_strategy(png_ptr,
+        strategy);
+
+    png_set_text_compression_window_bits(png_ptr,
+        window_bits);
+
+    png_set_text_compression_method(png_ptr, method);
+    #endif
+
+Controlling row filtering
+
+If you want to control whether libpng uses filtering or not, which
+filters are used, and how it goes about picking row filters, you
+can call one of these functions.  The selection and configuration
+of row filters can have a significant impact on the size and
+encoding speed and a somewhat lesser impact on the decoding speed
+of an image.  Filtering is enabled by default for RGB and grayscale
+images (with and without alpha), but not for paletted images nor
+for any images with bit depths less than 8 bits/pixel.
+
+The 'method' parameter sets the main filtering method, which is
+currently only '0' in the PNG 1.2 specification.  The 'filters'
+parameter sets which filter(s), if any, should be used for each
+scanline.  Possible values are PNG_ALL_FILTERS, PNG_NO_FILTERS,
+or PNG_FAST_FILTERS to turn filtering on and off, or to turn on
+just the fast-decoding subset of filters, respectively.
+
+Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
+PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
+ORed together with '|' to specify one or more filters to use.
+These filters are described in more detail in the PNG specification.
+If you intend to change the filter type during the course of writing
+the image, you should start with flags set for all of the filters
+you intend to use so that libpng can initialize its internal
+structures appropriately for all of the filter types.  (Note that this
+means the first row must always be adaptively filtered, because libpng
+currently does not allocate the filter buffers until png_write_row()
+is called for the first time.)
+
+    filters = PNG_NO_FILTERS;
+    filters = PNG_ALL_FILTERS;
+    filters = PNG_FAST_FILTERS;
+
+    or
+
+    filters = PNG_FILTER_NONE | PNG_FILTER_SUB |
+              PNG_FILTER_UP | PNG_FILTER_AVG |
+              PNG_FILTER_PAETH;
+
+    png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
+       filters);
+
+              The second parameter can also be
+              PNG_INTRAPIXEL_DIFFERENCING if you are
+              writing a PNG to be embedded in a MNG
+              datastream.  This parameter must be the
+              same as the value of filter_method used
+              in png_set_IHDR().
+
+Requesting debug printout
+
+The macro definition PNG_DEBUG can be used to request debugging
+printout.  Set it to an integer value in the range 0 to 3.  Higher
+numbers result in increasing amounts of debugging information.  The
+information is printed to the "stderr" file, unless another file
+name is specified in the PNG_DEBUG_FILE macro definition.
+
+When PNG_DEBUG > 0, the following functions (macros) become available:
+
+   png_debug(level, message)
+   png_debug1(level, message, p1)
+   png_debug2(level, message, p1, p2)
+
+in which "level" is compared to PNG_DEBUG to decide whether to print
+the message, "message" is the formatted string to be printed,
+and p1 and p2 are parameters that are to be embedded in the string
+according to printf-style formatting directives.  For example,
+
+   png_debug1(2, "foo=%d", foo);
+
+is expanded to
+
+   if (PNG_DEBUG > 2)
+      fprintf(PNG_DEBUG_FILE, "foo=%d\n", foo);
+
+When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
+can still use PNG_DEBUG to control your own debugging:
+
+   #ifdef PNG_DEBUG
+       fprintf(stderr, ...
+   #endif
+
+When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
+having level = 0 will be printed.  There aren't any such statements in
+this version of libpng, but if you insert some they will be printed.
+
+VII. MNG support
+
+The MNG specification (available at http://www.libpng.org/pub/mng) allows
+certain extensions to PNG for PNG images that are embedded in MNG datastreams.
+Libpng can support some of these extensions.  To enable them, use the
+png_permit_mng_features() function:
+
+   feature_set = png_permit_mng_features(png_ptr, mask)
+
+   mask is a png_uint_32 containing the bitwise OR of the
+        features you want to enable.  These include
+        PNG_FLAG_MNG_EMPTY_PLTE
+        PNG_FLAG_MNG_FILTER_64
+        PNG_ALL_MNG_FEATURES
+
+   feature_set is a png_uint_32 that is the bitwise AND of
+      your mask with the set of MNG features that is
+      supported by the version of libpng that you are using.
+
+It is an error to use this function when reading or writing a standalone
+PNG file with the PNG 8-byte signature.  The PNG datastream must be wrapped
+in a MNG datastream.  As a minimum, it must have the MNG 8-byte signature
+and the MHDR and MEND chunks.  Libpng does not provide support for these
+or any other MNG chunks; your application must provide its own support for
+them.  You may wish to consider using libmng (available at
+https://www.libmng.com/) instead.
+
+VIII. Changes to Libpng from version 0.88
+
+It should be noted that versions of libpng later than 0.96 are not
+distributed by the original libpng author, Guy Schalnat, nor by
+Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
+distributed versions 0.89 through 0.96, but rather by another member
+of the original PNG Group, Glenn Randers-Pehrson.  Guy and Andreas are
+still alive and well, but they have moved on to other things.
+
+The old libpng functions png_read_init(), png_write_init(),
+png_info_init(), png_read_destroy(), and png_write_destroy() have been
+moved to PNG_INTERNAL in version 0.95 to discourage their use.  These
+functions will be removed from libpng version 1.4.0.
+
+The preferred method of creating and initializing the libpng structures is
+via the png_create_read_struct(), png_create_write_struct(), and
+png_create_info_struct() because they isolate the size of the structures
+from the application, allow version error checking, and also allow the
+use of custom error handling routines during the initialization, which
+the old functions do not.  The functions png_read_destroy() and
+png_write_destroy() do not actually free the memory that libpng
+allocated for these structs, but just reset the data structures, so they
+can be used instead of png_destroy_read_struct() and
+png_destroy_write_struct() if you feel there is too much system overhead
+allocating and freeing the png_struct for each image read.
+
+Setting the error callbacks via png_set_message_fn() before
+png_read_init() as was suggested in libpng-0.88 is no longer supported
+because this caused applications that do not use custom error functions
+to fail if the png_ptr was not initialized to zero.  It is still possible
+to set the error callbacks AFTER png_read_init(), or to change them with
+png_set_error_fn(), which is essentially the same function, but with a new
+name to force compilation errors with applications that try to use the old
+method.
+
+Support for the sCAL, iCCP, iTXt, and sPLT chunks was added at libpng-1.0.6;
+however, iTXt support was not enabled by default.
+
+Starting with version 1.0.7, you can find out which version of the library
+you are using at run-time:
+
+   png_uint_32 libpng_vn = png_access_version_number();
+
+The number libpng_vn is constructed from the major version, minor
+version with leading zero, and release number with leading zero,
+(e.g., libpng_vn for version 1.0.7 is 10007).
+
+Note that this function does not take a png_ptr, so you can call it
+before you've created one.
+
+You can also check which version of png.h you used when compiling your
+application:
+
+   png_uint_32 application_vn = PNG_LIBPNG_VER;
+
+IX. Changes to Libpng from version 1.0.x to 1.2.x
+
+Support for user memory management was enabled by default.  To
+accomplish this, the functions png_create_read_struct_2(),
+png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
+png_malloc_default(), and png_free_default() were added.
+
+Support for the iTXt chunk has been enabled by default as of
+version 1.2.41.
+
+Support for certain MNG features was enabled.
+
+Support for numbered error messages was added.  However, we never got
+around to actually numbering the error messages.  The function
+png_set_strip_error_numbers() was added (Note: the prototype for this
+function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
+builds of libpng-1.2.15.  It was restored in libpng-1.2.36).
+
+The png_malloc_warn() function was added at libpng-1.2.3.  This issues
+a png_warning and returns NULL instead of aborting when it fails to
+acquire the requested memory allocation.
+
+Support for setting user limits on image width and height was enabled
+by default.  The functions png_set_user_limits(), png_get_user_width_max(),
+and png_get_user_height_max() were added at libpng-1.2.6.
+
+The png_set_add_alpha() function was added at libpng-1.2.7.
+
+The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
+Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
+tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
+deprecated.
+
+A number of macro definitions in support of runtime selection of
+assembler code features (especially Intel MMX code support) were
+added at libpng-1.2.0:
+
+    PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
+    PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+    PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
+    PNG_ASM_FLAG_MMX_READ_INTERLACE
+    PNG_ASM_FLAG_MMX_READ_FILTER_SUB
+    PNG_ASM_FLAG_MMX_READ_FILTER_UP
+    PNG_ASM_FLAG_MMX_READ_FILTER_AVG
+    PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
+    PNG_ASM_FLAGS_INITIALIZED
+    PNG_MMX_READ_FLAGS
+    PNG_MMX_FLAGS
+    PNG_MMX_WRITE_FLAGS
+    PNG_MMX_FLAGS
+
+We added the following functions in support of runtime
+selection of assembler code features:
+
+    png_get_mmx_flagmask()
+    png_set_mmx_thresholds()
+    png_get_asm_flags()
+    png_get_mmx_bitdepth_threshold()
+    png_get_mmx_rowbytes_threshold()
+    png_set_asm_flags()
+
+We replaced all of these functions with simple stubs in libpng-1.2.20,
+when the Intel assembler code was removed due to a licensing issue.
+
+These macros are deprecated:
+
+    PNG_READ_TRANSFORMS_NOT_SUPPORTED
+    PNG_PROGRESSIVE_READ_NOT_SUPPORTED
+    PNG_NO_SEQUENTIAL_READ_SUPPORTED
+    PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
+    PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
+    PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+They have been replaced, respectively, by:
+
+    PNG_NO_READ_TRANSFORMS
+    PNG_NO_PROGRESSIVE_READ
+    PNG_NO_SEQUENTIAL_READ
+    PNG_NO_WRITE_TRANSFORMS
+    PNG_NO_READ_ANCILLARY_CHUNKS
+    PNG_NO_WRITE_ANCILLARY_CHUNKS
+
+PNG_MAX_UINT was replaced with PNG_UINT_31_MAX.  It has been
+deprecated since libpng-1.0.16 and libpng-1.2.6.
+
+The function
+    png_check_sig(sig, num)
+was replaced with
+    !png_sig_cmp(sig, 0, num)
+It has been deprecated since libpng-0.90.
+
+The function
+    png_set_gray_1_2_4_to_8()
+which also expands tRNS to alpha was replaced with
+    png_set_expand_gray_1_2_4_to_8()
+which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
+
+X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+
+Private libpng prototypes and macro definitions were moved from
+png.h and pngconf.h into a new pngpriv.h header file.
+
+Functions png_set_benign_errors(), png_benign_error(), and
+png_chunk_benign_error() were added.
+
+Support for setting the maximum amount of memory that the application
+will allocate for reading chunks was added, as a security measure.
+The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
+were added to the library.
+
+We implemented support for I/O states by adding png_ptr member io_state
+and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+
+We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
+input transforms.
+
+Checking for and reporting of errors in the IHDR chunk is more thorough.
+
+Support for global arrays was removed, to improve thread safety.
+
+Some obsolete/deprecated macros and functions have been removed.
+
+Typecasted NULL definitions such as
+   #define png_voidp_NULL            (png_voidp)NULL
+were eliminated.  If you used these in your application, just use
+NULL instead.
+
+The png_struct and info_struct members "trans" and "trans_values" were
+changed to "trans_alpha" and "trans_color", respectively.
+
+The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
+were removed.
+
+The PNG_1_0_X and PNG_1_2_X macros were eliminated.
+
+The PNG_LEGACY_SUPPORTED macro was eliminated.
+
+Many WIN32_WCE #ifdefs were removed.
+
+The functions png_read_init(info_ptr), png_write_init(info_ptr),
+png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
+have been removed.  They have been deprecated since libpng-0.95.
+
+The png_permit_empty_plte() was removed. It has been deprecated
+since libpng-1.0.9.  Use png_permit_mng_features() instead.
+
+We removed the obsolete stub functions png_get_mmx_flagmask(),
+png_set_mmx_thresholds(), png_get_asm_flags(),
+png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
+png_set_asm_flags(), and png_mmx_supported()
+
+We removed the obsolete png_check_sig(), png_memcpy_check(), and
+png_memset_check() functions.  Instead use !png_sig_cmp(), memcpy(),
+and memset(), respectively.
+
+The function png_set_gray_1_2_4_to_8() was removed. It has been
+deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
+png_set_expand_gray_1_2_4_to_8() because the former function also
+expanded any tRNS chunk to an alpha channel.
+
+Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32
+were added and are used by default instead of the corresponding
+functions. Unfortunately,
+from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+
+We changed the prototype for png_malloc() from
+    png_malloc(png_structp png_ptr, png_uint_32 size)
+to
+    png_malloc(png_structp png_ptr, png_alloc_size_t size)
+
+This also applies to the prototype for the user replacement malloc_fn().
+
+The png_calloc() function was added and is used in place of
+of "png_malloc(); memset();" except in the case in png_read_png()
+where the array consists of pointers; in this case a "for" loop is used
+after the png_malloc() to set the pointers to NULL, to give robust.
+behavior in case the application runs out of memory part-way through
+the process.
+
+We changed the prototypes of png_get_compression_buffer_size() and
+png_set_compression_buffer_size() to work with size_t instead of
+png_uint_32.
+
+Support for numbered error messages was removed by default, since we
+never got around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was removed from the library by default.
+
+The png_zalloc() and png_zfree() functions are no longer exported.
+The png_zalloc() function no longer zeroes out the memory that it
+allocates.  Applications that called png_zalloc(png_ptr, number, size)
+can call png_calloc(png_ptr, number*size) instead, and can call
+png_free() instead of png_zfree().
+
+Support for dithering was disabled by default in libpng-1.4.0, because
+it has not been well tested and doesn't actually "dither".
+The code was not
+removed, however, and could be enabled by building libpng with
+PNG_READ_DITHER_SUPPORTED defined.  In libpng-1.4.2, this support
+was re-enabled, but the function was renamed png_set_quantize() to
+reflect more accurately what it actually does.  At the same time,
+the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
+PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED
+was renamed to PNG_READ_QUANTIZE_SUPPORTED.
+
+We removed the trailing '.' from the warning and error messages.
+
+XI. Changes to Libpng from version 1.4.x to 1.5.x
+
+From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+The incorrect macro was removed from libpng-1.4.5.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+   png_set_check_for_invalid_index(png_ptr, allowed);
+
+      allowed  - one of
+                 0: disable benign error (accept the
+                    invalid data without warning).
+                 1: enable benign error (treat the
+                    invalid data as an error or a
+                    warning).
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are decoded as opaque black by the decoder and written
+as-is by the encoder.
+
+Retrieving the maximum palette index found was added at libpng-1.5.15.
+This statement must appear after png_read_png() or png_read_image() while
+reading, and after png_write_png() or png_write_image() while writing.
+
+   int max_palette = png_get_palette_max(png_ptr, info_ptr);
+
+This will return the maximum palette index found in the image, or "-1" if
+the palette was not checked, or "0" if no palette was found.  Note that this
+does not account for any palette index used by ancillary chunks such as the
+bKGD chunk; you must check those separately to determine the maximum
+palette index actually used.
+
+There are no substantial API changes between the non-deprecated parts of
+the 1.4.5 API and the 1.5.0 API; however, the ability to directly access
+members of the main libpng control structures, png_struct and png_info,
+deprecated in earlier versions of libpng, has been completely removed from
+libpng 1.5, and new private "pngstruct.h", "pnginfo.h", and "pngdebug.h"
+header files were created.
+
+We no longer include zlib.h in png.h.  The include statement has been moved
+to pngstruct.h, where it is not accessible by applications. Applications that
+need access to information in zlib.h will need to add the '#include "zlib.h"'
+directive.  It does not matter whether this is placed prior to or after
+the '"#include png.h"' directive.
+
+The png_sprintf(), png_strcpy(), and png_strncpy() macros are no longer used
+and were removed.
+
+We moved the png_strlen(), png_memcpy(), png_memset(), and png_memcmp()
+macros into a private header file (pngpriv.h) that is not accessible to
+applications.
+
+In png_get_iCCP, the type of "profile" was changed from png_charpp
+to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep.
+
+There are changes of form in png.h, including new and changed macros to
+declare parts of the API.  Some API functions with arguments that are
+pointers to data not modified within the function have been corrected to
+declare these arguments with const.
+
+Much of the internal use of C macros to control the library build has also
+changed and some of this is visible in the exported header files, in
+particular the use of macros to control data and API elements visible
+during application compilation may require significant revision to
+application code.  (It is extremely rare for an application to do this.)
+
+Any program that compiled against libpng 1.4 and did not use deprecated
+features or access internal library structures should compile and work
+against libpng 1.5, except for the change in the prototype for
+png_get_iCCP() and png_set_iCCP() API functions mentioned above.
+
+libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of
+interlaced images.  The macros return the number of rows and columns in
+each pass and information that can be used to de-interlace and (if
+absolutely necessary) interlace an image.
+
+libpng 1.5.0 adds an API png_longjmp(png_ptr, value).  This API calls
+the application-provided png_longjmp_ptr on the internal, but application
+initialized, longjmp buffer.  It is provided as a convenience to avoid
+the need to use the png_jmpbuf macro, which had the unnecessary side
+effect of resetting the internal png_longjmp_ptr value.
+
+libpng 1.5.0 includes a complete fixed point API.  By default this is
+present along with the corresponding floating point API.  In general the
+fixed point API is faster and smaller than the floating point one because
+the PNG file format used fixed point, not floating point.  This applies
+even if the library uses floating point in internal calculations.  A new
+macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library
+uses floating point arithmetic (the default) or fixed point arithmetic
+internally for performance critical calculations such as gamma correction.
+In some cases, the gamma calculations may produce slightly different
+results.  This has changed the results in png_rgb_to_gray and in alpha
+composition (png_set_background for example). This applies even if the
+original image was already linear (gamma == 1.0) and, therefore, it is
+not necessary to linearize the image.  This is because libpng has *not*
+been changed to optimize that case correctly, yet.
+
+Fixed point support for the sCAL chunk comes with an important caveat;
+the sCAL specification uses a decimal encoding of floating point values
+and the accuracy of PNG fixed point values is insufficient for
+representation of these values. Consequently a "string" API
+(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
+arbitrary sCAL chunks in the absence of either the floating point API or
+internal floating point calculations.  Starting with libpng-1.5.0, both
+of these functions are present when PNG_sCAL_SUPPORTED is defined.  Prior
+to libpng-1.5.0, their presence also depended upon PNG_FIXED_POINT_SUPPORTED
+being defined and PNG_FLOATING_POINT_SUPPORTED not being defined.
+
+Applications no longer need to include the optional distribution header
+file pngusr.h or define the corresponding macros during application
+build in order to see the correct variant of the libpng API.  From 1.5.0
+application code can check for the corresponding _SUPPORTED macro:
+
+#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
+   /* code that uses the inch conversion APIs. */
+#endif
+
+This macro will only be defined if the inch conversion functions have been
+compiled into libpng.  The full set of macros, and whether or not support
+has been compiled in, are available in the header file pnglibconf.h.
+This header file is specific to the libpng build.  Notice that prior to
+1.5.0 the _SUPPORTED macros would always have the default definition unless
+reset by pngusr.h or by explicit settings on the compiler command line.
+These settings may produce compiler warnings or errors in 1.5.0 because
+of macro redefinition.
+
+Applications can now choose whether to use these macros or to call the
+corresponding function by defining PNG_USE_READ_MACROS or
+PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
+only supported from 1.5.0; defining PNG_NO_USE_READ_MACROS prior to 1.5.0
+will lead to a link failure.
+
+Prior to libpng-1.5.4, the zlib compressor used the same set of parameters
+when compressing the IDAT data and textual data such as zTXt and iCCP.
+In libpng-1.5.4 we reinitialized the zlib stream for each type of data.
+We added five png_set_text_*() functions for setting the parameters to
+use with textual data.
+
+Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+option was off by default, and slightly inaccurate scaling occurred.
+This option can no longer be turned off, and the choice of accurate
+or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
+API for accurate scaling or the old png_set_strip_16_to_8() API for simple
+chopping.  In libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+macro became PNG_READ_SCALE_16_TO_8_SUPPORTED, and the PNG_READ_16_TO_8
+macro became PNG_READ_STRIP_16_TO_8_SUPPORTED, to enable the two
+png_set_*_16_to_8() functions separately.
+
+Prior to libpng-1.5.4, the png_set_user_limits() function could only be
+used to reduce the width and height limits from the value of
+PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
+that it could be used to override them.  Now this function will reduce or
+increase the limits.
+
+Starting in libpng-1.5.22, default user limits were established. These
+can be overridden by application calls to png_set_user_limits(),
+png_set_user_chunk_cache_max(), and/or png_set_user_malloc_max().
+The limits are now
+                             max possible  default
+   png_user_width_max        0x7fffffff    1,000,000
+   png_user_height_max       0x7fffffff    1,000,000
+   png_user_chunk_cache_max  0 (unlimited) 1000
+   png_user_chunk_malloc_max 0 (unlimited) 8,000,000
+
+The png_set_option() function (and the "options" member of the png struct) was
+added to libpng-1.5.15, with option PNG_ARM_NEON.
+
+The library now supports a complete fixed point implementation and can
+thus be used on systems that have no floating point support or very
+limited or slow support.  Previously gamma correction, an essential part
+of complete PNG support, required reasonably fast floating point.
+
+As part of this the choice of internal implementation has been made
+independent of the choice of fixed versus floating point APIs and all the
+missing fixed point APIs have been implemented.
+
+The exact mechanism used to control attributes of API functions has
+changed, as described in the INSTALL file.
+
+A new test program, pngvalid, is provided in addition to pngtest.
+pngvalid validates the arithmetic accuracy of the gamma correction
+calculations and includes a number of validations of the file format.
+A subset of the full range of tests is run when "make check" is done
+(in the 'configure' build.)  pngvalid also allows total allocated memory
+usage to be evaluated and performs additional memory overwrite validation.
+
+Many changes to individual feature macros have been made. The following
+are the changes most likely to be noticed by library builders who
+configure libpng:
+
+1) All feature macros now have consistent naming:
+
+#define PNG_NO_feature turns the feature off
+#define PNG_feature_SUPPORTED turns the feature on
+
+pnglibconf.h contains one line for each feature macro which is either:
+
+#define PNG_feature_SUPPORTED
+
+if the feature is supported or:
+
+/*#undef PNG_feature_SUPPORTED*/
+
+if it is not.  Library code consistently checks for the 'SUPPORTED' macro.
+It does not, and libpng applications should not, check for the 'NO' macro
+which will not normally be defined even if the feature is not supported.
+The 'NO' macros are only used internally for setting or not setting the
+corresponding 'SUPPORTED' macros.
+
+Compatibility with the old names is provided as follows:
+
+PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED
+
+And the following definitions disable the corresponding feature:
+
+PNG_SETJMP_NOT_SUPPORTED disables SETJMP
+PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS
+PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV
+PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS
+PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS
+PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS
+
+Library builders should remove use of the above, inconsistent, names.
+
+2) Warning and error message formatting was previously conditional on
+the STDIO feature. The library has been changed to use the
+CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled
+the library no longer uses the printf(3) functions, even though the
+default read/write implementations use (FILE) style stdio.h functions.
+
+3) Three feature macros now control the fixed/floating point decisions:
+
+PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs
+
+PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in
+practice these are normally required internally anyway (because the PNG
+file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT
+merely stops the function from being exported.
+
+PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating
+point implementation or the fixed point one.  Typically the fixed point
+implementation is larger and slower than the floating point implementation
+on a system that supports floating point; however, it may be faster on a
+system which lacks floating point hardware and therefore uses a software
+emulation.
+
+4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the
+functions to read and write ints to be disabled independently of
+PNG_USE_READ_MACROS, which allows libpng to be built with the functions
+even though the default is to use the macros - this allows applications
+to choose at app buildtime whether or not to use macros (previously
+impossible because the functions weren't in the default build.)
+
+XII. Changes to Libpng from version 1.5.x to 1.6.x
+
+A "simplified API" has been added (see documentation in png.h and a simple
+example in contrib/examples/pngtopng.c).  The new publicly visible API
+includes the following:
+
+   macros:
+     PNG_FORMAT_*
+     PNG_IMAGE_*
+   structures:
+     png_control
+     png_image
+   read functions
+     png_image_begin_read_from_file()
+     png_image_begin_read_from_stdio()
+     png_image_begin_read_from_memory()
+     png_image_finish_read()
+     png_image_free()
+   write functions
+     png_image_write_to_file()
+     png_image_write_to_memory()
+     png_image_write_to_stdio()
+
+Starting with libpng-1.6.0, you can configure libpng to prefix all exported
+symbols, using the PNG_PREFIX macro.
+
+We no longer include string.h in png.h.  The include statement has been moved
+to pngpriv.h, where it is not accessible by applications.  Applications that
+need access to information in string.h must add an '#include <string.h>'
+directive.  It does not matter whether this is placed prior to or after
+the '#include "png.h"' directive.
+
+The following API are now DEPRECATED:
+   png_info_init_3()
+   png_convert_to_rfc1123() which has been replaced
+     with png_convert_to_rfc1123_buffer()
+   png_malloc_default()
+   png_free_default()
+   png_reset_zstream()
+
+The following have been removed:
+   png_get_io_chunk_name(), which has been replaced
+     with png_get_io_chunk_type().  The new
+     function returns a 32-bit integer instead of
+     a string.
+   The png_sizeof(), png_strlen(), png_memcpy(), png_memcmp(), and
+     png_memset() macros are no longer used in the libpng sources and
+     have been removed.  These had already been made invisible to applications
+     (i.e., defined in the private pngpriv.h header file) since libpng-1.5.0.
+
+The signatures of many exported functions were changed, such that
+   png_structp became png_structrp or png_const_structrp
+   png_infop became png_inforp or png_const_inforp
+where "rp" indicates a "restricted pointer".
+
+Dropped support for 16-bit platforms. The support for FAR/far types has
+been eliminated and the definition of png_alloc_size_t is now controlled
+by a flag so that 'small size_t' systems can select it if necessary.
+
+Error detection in some chunks has improved; in particular the iCCP chunk
+reader now does pretty complete validation of the basic format.  Some bad
+profiles that were previously accepted are now accepted with a warning or
+rejected, depending upon the png_set_benign_errors() setting, in particular
+the very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
+libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
+means of
+
+    #if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && \
+        defined(PNG_SET_OPTION_SUPPORTED)
+       png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE,
+           PNG_OPTION_ON);
+    #endif
+
+It's not a good idea to do this if you are using the "simplified API",
+which needs to be able to recognize sRGB profiles conveyed via the iCCP
+chunk.
+
+The PNG spec requirement that only grayscale profiles may appear in images
+with color type 0 or 4 and that even if the image only contains gray pixels,
+only RGB profiles may appear in images with color type 2, 3, or 6, is now
+enforced.  The sRGB chunk is allowed to appear in images with any color type
+and is interpreted by libpng to convey a one-tracer-curve gray profile or a
+three-tracer-curve RGB profile as appropriate.
+
+Libpng 1.5.x erroneously used /MD for Debug DLL builds; if you used the debug
+builds in your app and you changed your app to use /MD you will need to
+change it back to /MDd for libpng 1.6.x.
+
+Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
+an empty language field or an empty translated keyword.  Both of these
+are allowed by the PNG specification, so these warnings are no longer issued.
+
+The library now issues an error if the application attempts to set a
+transform after it calls png_read_update_info() or if it attempts to call
+both png_read_update_info() and png_start_read_image() or to call either
+of them more than once.
+
+The default condition for benign_errors is now to treat benign errors as
+warnings while reading and as errors while writing.
+
+The library now issues a warning if both background processing and RGB to
+gray are used when gamma correction happens. As with previous versions of
+the library the results are numerically very incorrect in this case.
+
+There are some minor arithmetic changes in some transforms such as
+png_set_background(), that might be detected by certain regression tests.
+
+Unknown chunk handling has been improved internally, without any API change.
+This adds more correct option control of the unknown handling, corrects
+a pre-existing bug where the per-chunk 'keep' setting is ignored, and makes
+it possible to skip IDAT chunks in the sequential reader.
+
+The machine-generated configure files are no longer included in branches
+libpng16 and later of the GIT repository.  They continue to be included
+in the tarball releases, however.
+
+Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT
+stream to set the size of the sliding window for reading instead of using the
+default 32-kbyte sliding window size.  It was discovered that there are
+hundreds of PNG files in the wild that have incorrect CMF bytes that caused
+zlib to issue the "invalid distance too far back" error and reject the file.
+Libpng-1.6.3 and later calculate their own safe CMF from the image dimensions,
+provide a way to revert to the libpng-1.5.x behavior (ignoring the CMF bytes
+and using a 32-kbyte sliding window), by using
+
+    png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW,
+        PNG_OPTION_ON);
+
+and provide a tool (contrib/tools/pngfix) for rewriting a PNG file while
+optimizing the CMF bytes in its IDAT chunk correctly.
+
+Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
+length, which resulted in PNG files that cannot be read beyond the bad iTXt
+chunk.  This error was fixed in libpng-1.6.3, and a tool (called
+contrib/tools/png-fix-itxt) has been added to the libpng distribution.
+
+Starting with libpng-1.6.17, the PNG_SAFE_LIMITS macro was eliminated
+and safe limits are used by default (users who need larger limits
+can still override them at compile time or run time, as described above).
+
+The new limits are
+                                default   spec limit
+   png_user_width_max         1,000,000  2,147,483,647
+   png_user_height_max        1,000,000  2,147,483,647
+   png_user_chunk_cache_max         128  unlimited
+   png_user_chunk_malloc_max  8,000,000  unlimited
+
+Starting with libpng-1.6.18, a PNG_RELEASE_BUILD macro was added, which allows
+library builders to control compilation for an installed system (a release build).
+It can be set for testing debug or beta builds to ensure that they will compile
+when the build type is switched to RC or STABLE. In essence this overrides the
+PNG_LIBPNG_BUILD_BASE_TYPE definition which is not directly user controllable.
+
+Starting with libpng-1.6.19, attempting to set an over-length PLTE chunk
+is an error. Previously this requirement of the PNG specification was not
+enforced, and the palette was always limited to 256 entries. An over-length
+PLTE chunk found in an input PNG is silently truncated.
+
+Starting with libpng-1.6.31, the eXIf chunk is supported. Libpng does not
+attempt to decode the Exif profile; it simply returns a byte array
+containing the profile to the calling application which must do its own
+decoding.
+
+XIII. Detecting libpng
+
+The png_get_io_ptr() function has been present since libpng-0.88, has never
+changed, and is unaffected by conditional compilation macros.  It is the
+best choice for use in configure scripts for detecting the presence of any
+libpng version since 0.88.  In an autoconf "configure.in" you could use
+
+    AC_CHECK_LIB(png, png_get_io_ptr, ...
+
+XV. Source code repository
+
+Since about February 2009, version 1.2.34, libpng has been under "git" source
+control.  The git repository was built from old libpng-x.y.z.tar.gz files
+going back to version 0.70.  You can access the git repository (read only)
+at
+
+    https://github.com/glennrp/libpng or
+    https://git.code.sf.net/p/libpng/code.git
+
+or you can browse it with a web browser at
+
+    https://github.com/glennrp/libpng or
+    https://sourceforge.net/p/libpng/code/ci/libpng16/tree/
+
+Patches can be sent to png-mng-implement at lists.sourceforge.net or
+uploaded to the libpng bug tracker at
+
+    https://libpng.sourceforge.io/
+
+or as a "pull request" to
+
+    https://github.com/glennrp/libpng/pulls
+
+We also accept patches built from the tar or zip distributions, and
+simple verbal descriptions of bug fixes, reported either to the
+SourceForge bug tracker, to the png-mng-implement at lists.sf.net
+mailing list, as github issues.
+
+XV. Coding style
+
+Our coding style is similar to the "Allman" style
+(See https://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
+braces on separate lines:
+
+    if (condition)
+    {
+       action;
+    }
+
+    else if (another condition)
+    {
+       another action;
+    }
+
+The braces can be omitted from simple one-line actions:
+
+    if (condition)
+       return 0;
+
+We use 3-space indentation, except for continued statements which
+are usually indented the same as the first line of the statement
+plus four more spaces.
+
+For macro definitions we use 2-space indentation, always leaving the "#"
+in the first column.
+
+    #ifndef PNG_NO_FEATURE
+    #  ifndef PNG_FEATURE_SUPPORTED
+    #    define PNG_FEATURE_SUPPORTED
+    #  endif
+    #endif
+
+Comments appear with the leading "/*" at the same indentation as
+the statement that follows the comment:
+
+    /* Single-line comment */
+    statement;
+
+    /* This is a multiple-line
+     * comment.
+     */
+    statement;
+
+Very short comments can be placed after the end of the statement
+to which they pertain:
+
+    statement;    /* comment */
+
+We don't use C++ style ("//") comments. We have, however,
+used them in the past in some now-abandoned MMX assembler
+code.
+
+Functions and their curly braces are not indented, and
+exported functions are marked with PNGAPI:
+
+ /* This is a public function that is visible to
+  * application programmers. It does thus-and-so.
+  */
+ void PNGAPI
+ png_exported_function(png_ptr, png_info, foo)
+ {
+    body;
+ }
+
+The return type and decorations are placed on a separate line
+ahead of the function name, as illustrated above.
+
+The prototypes for all exported functions appear in png.h,
+above the comment that says
+
+    /* Maintainer: Put new public prototypes here ... */
+
+We mark all non-exported functions with "/* PRIVATE */"":
+
+ void /* PRIVATE */
+ png_non_exported_function(png_ptr, png_info, foo)
+ {
+    body;
+ }
+
+The prototypes for non-exported functions (except for those in
+pngtest) appear in pngpriv.h above the comment that says
+
+  /* Maintainer: Put new private prototypes here ^ */
+
+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
+We put a space after the "sizeof" operator and we omit the
+optional parentheses around its argument when the argument
+is an expression, not a type name, and we always enclose the
+sizeof operator, with its argument, in parentheses:
+
+  (sizeof (png_uint_32))
+  (sizeof array)
+
+Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
+though it were a function.
+
+Control keywords if, for, while, and switch are always followed by a space
+to distinguish them from function calls, which have no trailing space.
+
+We put a space after each comma and after each semicolon
+in "for" statements, and we put spaces before and after each
+C binary operator and after "for" or "while", and before
+"?".  We don't put a space between a typecast and the expression
+being cast, nor do we put one between a function name and the
+left parenthesis that follows it:
+
+    for (i = 2; i > 0; --i)
+       y[i] = a(x) + (int)b;
+
+We prefer #ifdef and #ifndef to #if defined() and #if !defined()
+when there is only one macro being tested.  We always use parentheses
+with "defined".
+
+We express integer constants that are used as bit masks in hex format,
+with an even number of lower-case hex digits, and to make them unsigned
+(e.g., 0x00U, 0xffU, 0x0100U) and long if they are greater than 0x7fff
+(e.g., 0xffffUL).
+
+We prefer to use underscores rather than camelCase in names, except
+for a few type names that we inherit from zlib.h.
+
+We prefer "if (something != 0)" and "if (something == 0)" over
+"if (something)" and if "(!something)", respectively, and for pointers
+we prefer "if (some_pointer != NULL)" or "if (some_pointer == NULL)".
+
+We do not use the TAB character for indentation in the C sources.
+
+Lines do not exceed 80 characters.
+
+Other rules can be inferred by inspecting the libpng source.
diff --git a/extern/libpng/libpng.3 b/extern/libpng/libpng.3
new file mode 100644
index 0000000000..f37423540d
--- /dev/null
+++ b/extern/libpng/libpng.3
@@ -0,0 +1,6052 @@
+.TH LIBPNG 3 "April 14, 2019"
+.SH NAME
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.37
+
+.SH SYNOPSIS
+\fB#include <png.h>\fP
+
+\fBpng_uint_32 png_access_version_number (void);\fP
+
+\fBvoid png_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fBvoid png_build_grayscale_palette (int \fP\fIbit_depth\fP\fB, png_colorp \fIpalette\fP\fB);\fP
+
+\fBpng_voidp png_calloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fBvoid png_chunk_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fBvoid png_chunk_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fBvoid png_chunk_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
+
+\fBvoid png_convert_from_struct_tm (png_timep \fP\fIptime\fP\fB, struct tm FAR * \fIttime\fP\fB);\fP
+
+\fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP
+
+\fBpng_charp png_convert_to_rfc1123 (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fIptime\fP\fB);\fP
+
+\fBpng_infop png_create_info_struct (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_structp png_create_read_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
+
+\fBpng_structp png_create_read_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fBpng_structp png_create_write_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
+
+\fBpng_structp png_create_write_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fBvoid png_data_freer (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIfreer\fP\fB, png_uint_32 \fImask\fP\fB);\fP
+
+\fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
+
+\fBvoid png_destroy_read_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fP\fIinfo_ptr_ptr\fP\fB, png_infopp \fIend_info_ptr_ptr\fP\fB);\fP
+
+\fBvoid png_destroy_write_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
+
+\fBvoid png_err (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fBvoid png_free (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
+
+\fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_free_default (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
+
+\fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP
+
+\fBpng_byte png_get_bit_depth (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_bKGD (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fI*background\fP\fB);\fP
+
+\fBpng_byte png_get_channels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_cHRM (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*white_x\fP\fB, double \fP\fI*white_y\fP\fB, double \fP\fI*red_x\fP\fB, double \fP\fI*red_y\fP\fB, double \fP\fI*green_x\fP\fB, double \fP\fI*green_y\fP\fB, double \fP\fI*blue_x\fP\fB, double \fI*blue_y\fP\fB);\fP
+
+\fBpng_uint_32 png_get_cHRM_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*white_x\fP\fB, png_uint_32 \fP\fI*white_y\fP\fB, png_uint_32 \fP\fI*red_x\fP\fB, png_uint_32 \fP\fI*red_y\fP\fB, png_uint_32 \fP\fI*green_x\fP\fB, png_uint_32 \fP\fI*green_y\fP\fB, png_uint_32 \fP\fI*blue_x\fP\fB, png_uint_32 \fI*blue_y\fP\fB);\fP
+
+\fBpng_uint_32 png_get_cHRM_XYZ (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*red_X\fP\fB, double \fP\fI*red_Y\fP\fB, double \fP\fI*red_Z\fP\fB, double \fP\fI*green_X\fP\fB, double \fP\fI*green_Y\fP\fB, double \fP\fI*green_Z\fP\fB, double \fP\fI*blue_X\fP\fB, double \fP\fI*blue_Y\fP\fB, double \fI*blue_Z\fP\fB);\fP
+
+\fBpng_uint_32 png_get_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fI*int_red_X\fP\fB, png_fixed_point \fP\fI*int_red_Y\fP\fB, png_fixed_point \fP\fI*int_red_Z\fP\fB, png_fixed_point \fP\fI*int_green_X\fP\fB, png_fixed_point \fP\fI*int_green_Y\fP\fB, png_fixed_point \fP\fI*int_green_Z\fP\fB, png_fixed_point \fP\fI*int_blue_X\fP\fB, png_fixed_point \fP\fI*int_blue_Y\fP\fB, png_fixed_point \fI*int_blue_Z\fP\fB);\fP
+
+\fBpng_uint_32 png_get_chunk_cache_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_alloc_size_t png_get_chunk_malloc_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_color_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_compression_buffer_size (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_compression_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_copyright (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_current_row_number \fI(png_const_structp\fP\fB);\fP
+
+\fBpng_byte png_get_current_pass_number \fI(png_const_structp\fP\fB);\fP
+
+\fBpng_voidp png_get_error_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_filter_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_gAMA (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fI*file_gamma\fP\fB);\fP
+
+\fBpng_uint_32 png_get_gAMA_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fI*int_file_gamma\fP\fB);\fP
+
+\fBpng_byte png_get_header_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_header_version (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_eXIf (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fI*exif\fP\fB);\fP
+
+\fBpng_uint_32 png_get_eXIf_1 (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_unit_32 \fP\fI*num_exif\fP\fB, png_bytep \fI*exif\fP\fB);\fP
+
+\fBpng_uint_32 png_get_hIST (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fI*hist\fP\fB);\fP
+
+\fBpng_uint_32 png_get_iCCP (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_bytepp \fP\fIprofile\fP\fB, png_uint_32 \fI*proflen\fP\fB);\fP
+
+\fBpng_uint_32 png_get_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*width\fP\fB, png_uint_32 \fP\fI*height\fP\fB, int \fP\fI*bit_depth\fP\fB, int \fP\fI*color_type\fP\fB, int \fP\fI*interlace_type\fP\fB, int \fP\fI*compression_type\fP\fB, int \fI*filter_type\fP\fB);\fP
+
+\fBpng_uint_32 png_get_image_height (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_image_width (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_int_32 (png_bytep \fIbuf\fP\fB);\fP
+
+\fBpng_byte png_get_interlace_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_io_chunk_type (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_voidp png_get_io_ptr (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_io_state (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_libpng_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBint png_get_palette_max(png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_voidp png_get_mem_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_oFFs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*offset_x\fP\fB, png_uint_32 \fP\fI*offset_y\fP\fB, int \fI*unit_type\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fI*purpose\fP\fB, png_int_32 \fP\fI*X0\fP\fB, png_int_32 \fP\fI*X1\fP\fB, int \fP\fI*type\fP\fB, int \fP\fI*nparams\fP\fB, png_charp \fP\fI*units\fP\fB, png_charpp \fI*params\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pHYs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
+
+\fBfloat png_get_pixel_aspect_ratio (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pHYs_dpi (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
+
+\fBpng_fixed_point png_get_pixel_aspect_ratio_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_voidp png_get_progressive_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_PLTE (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fI*palette\fP\fB, int \fI*num_palette\fP\fB);\fP
+
+\fBpng_byte png_get_rgb_to_gray_status (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_rowbytes (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_bytepp png_get_rows (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_sBIT (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fI*sig_bit\fP\fB);\fP
+
+\fBvoid png_get_sCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, double* \fP\fIwidth\fP\fB, double* \fIheight\fP\fB);\fP
+
+\fBvoid png_get_sCAL_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_fixed_pointp \fP\fIwidth\fP\fB, png_fixed_pointp \fIheight\fP\fB);\fP
+
+\fBvoid png_get_sCAL_s (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_charpp \fP\fIwidth\fP\fB, png_charpp \fIheight\fP\fB);\fP
+
+\fBpng_bytep png_get_signature (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_sPLT (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fI*splt_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_sRGB (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int \fI*file_srgb_intent\fP\fB);\fP
+
+\fBpng_uint_32 png_get_text (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fI*text_ptr\fP\fB, int \fI*num_text\fP\fB);\fP
+
+\fBpng_uint_32 png_get_tIME (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fI*mod_time\fP\fB);\fP
+
+\fBpng_uint_32 png_get_tRNS (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fI*trans_alpha\fP\fB, int \fP\fI*num_trans\fP\fB, png_color_16p \fI*trans_color\fP\fB);\fP
+
+\fB/* This function is really an inline macro. \fI*/
+
+\fBpng_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP
+
+\fBpng_uint_32 png_get_uint_31 (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIbuf\fP\fB);\fP
+
+\fB/* This function is really an inline macro. \fI*/
+
+\fBpng_uint_32 png_get_uint_32 (png_bytep \fIbuf\fP\fB);\fP
+
+\fBpng_uint_32 png_get_unknown_chunks (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkpp \fIunknowns\fP\fB);\fP
+
+\fBpng_voidp png_get_user_chunk_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_user_height_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_voidp png_get_user_transform_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_user_width_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_valid (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIflag\fP\fB);\fP
+
+\fBfloat png_get_x_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_fixed_point png_get_x_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_x_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_x_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_x_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_x_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBfloat png_get_y_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_fixed_point png_get_y_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_y_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_y_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_y_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_y_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP
+
+\fBint png_image_begin_read_from_file (png_imagep \fP\fIimage\fP\fB, const char \fI*file_name\fP\fB);\fP
+
+\fBint png_image_begin_read_from_stdio (png_imagep \fP\fIimage\fP\fB, FILE* \fIfile\fP\fB);\fP
+
+\fBint, png_image_begin_read_from_memory (png_imagep \fP\fIimage\fP\fB, png_const_voidp \fP\fImemory\fP\fB, size_t \fIsize\fP\fB);\fP
+
+\fBint png_image_finish_read (png_imagep \fP\fIimage\fP\fB, png_colorp \fP\fIbackground\fP\fB, void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP
+
+\fBvoid png_image_free (png_imagep \fIimage\fP\fB);\fP
+
+\fBint png_image_write_to_file (png_imagep \fP\fIimage\fP\fB, const char \fP\fI*file\fP\fB, int \fP\fIconvert_to_8bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP
+
+\fBint png_image_write_to_memory (png_imagep \fP\fIimage\fP\fB, void \fP\fI*memory\fP\fB, png_alloc_size_t * PNG_RESTRICT \fP\fImemory_bytes\fP\fB, int \fP\fIconvert_to_8_bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, const void \fI*colormap\fP\fB);\fP
+
+\fBint png_image_write_to_stdio (png_imagep \fP\fIimage\fP\fB, FILE \fP\fI*file\fP\fB, int \fP\fIconvert_to_8_bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP
+
+\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, size_t \fIpng_info_struct_size\fP\fB);\fP
+
+\fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP
+
+\fBvoid png_longjmp (png_structp \fP\fIpng_ptr\fP\fB, int \fIval\fP\fB);\fP
+
+\fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fBpng_voidp png_malloc_default (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fBpng_voidp png_malloc_warn (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fBpng_uint_32 png_permit_mng_features (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fImng_features_permitted\fP\fB);\fP
+
+\fBvoid png_process_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, size_t \fIbuffer_size\fP\fB);\fP
+
+\fBsize_t png_process_data_pause (png_structp \fP\fIpng_ptr\fP\fB, int \fIsave\fP\fB);\fP
+
+\fBpng_uint_32 png_process_data_skip (png_structp \fP\fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_progressive_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIold_row\fP\fB, png_bytep \fInew_row\fP\fB);\fP
+
+\fBvoid png_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_read_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
+
+\fBvoid png_read_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_read_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
+
+\fBvoid png_read_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fIdisplay_row\fP\fB);\fP
+
+\fBvoid png_read_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_bytepp \fP\fIdisplay_row\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
+
+\fBvoid png_read_update_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBint png_reset_zstream (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP
+
+\fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP
+
+\fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP
+
+\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
+
+\fBvoid png_set_alpha_mode (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, double \fIoutput_gamma\fP\fB);\fP
+
+\fBvoid png_set_alpha_mode_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, png_fixed_point \fIoutput_gamma\fP\fB);\fP
+
+\fBvoid png_set_background (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, double \fIbackground_gamma\fP\fB);\fP
+
+\fBvoid png_set_background_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, png_uint_32 \fIbackground_gamma\fP\fB);\fP
+
+\fBvoid png_set_benign_errors (png_structp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP
+
+\fBvoid png_set_bgr (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fIbackground\fP\fB);\fP
+
+\fBvoid png_set_check_for_invalid_index (png_structrp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP
+
+\fBvoid png_set_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIwhite_x\fP\fB, double \fP\fIwhite_y\fP\fB, double \fP\fIred_x\fP\fB, double \fP\fIred_y\fP\fB, double \fP\fIgreen_x\fP\fB, double \fP\fIgreen_y\fP\fB, double \fP\fIblue_x\fP\fB, double \fIblue_y\fP\fB);\fP
+
+\fBvoid png_set_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwhite_x\fP\fB, png_uint_32 \fP\fIwhite_y\fP\fB, png_uint_32 \fP\fIred_x\fP\fB, png_uint_32 \fP\fIred_y\fP\fB, png_uint_32 \fP\fIgreen_x\fP\fB, png_uint_32 \fP\fIgreen_y\fP\fB, png_uint_32 \fP\fIblue_x\fP\fB, png_uint_32 \fIblue_y\fP\fB);\fP
+
+\fBvoid png_set_cHRM_XYZ (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIred_X\fP\fB, double \fP\fIred_Y\fP\fB, double \fP\fIred_Z\fP\fB, double \fP\fIgreen_X\fP\fB, double \fP\fIgreen_Y\fP\fB, double \fP\fIgreen_Z\fP\fB, double \fP\fIblue_X\fP\fB, double \fP\fIblue_Y\fP\fB, double \fIblue_Z\fP\fB);\fP
+
+\fBvoid png_set_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fIint_red_X\fP\fB, png_fixed_point \fP\fIint_red_Y\fP\fB, png_fixed_point \fP\fIint_red_Z\fP\fB, png_fixed_point \fP\fIint_green_X\fP\fB, png_fixed_point \fP\fIint_green_Y\fP\fB, png_fixed_point \fP\fIint_green_Z\fP\fB, png_fixed_point \fP\fIint_blue_X\fP\fB, png_fixed_point \fP\fIint_blue_Y\fP\fB, png_fixed_point \fIint_blue_Z\fP\fB);\fP
+
+\fBvoid png_set_chunk_cache_max (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIuser_chunk_cache_max\fP\fB);\fP
+
+\fBvoid png_set_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
+
+\fBvoid png_set_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
+
+\fBvoid png_set_compression_method (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod\fP\fB);\fP
+
+\fBvoid png_set_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
+
+\fBvoid png_set_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
+
+\fBvoid png_set_crc_action (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcrit_action\fP\fB, int \fIancil_action\fP\fB);\fP
+
+\fBvoid png_set_error_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarning_fn\fP\fB);\fP
+
+\fBvoid png_set_expand (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_expand_16 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_expand_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_filler (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
+
+\fBvoid png_set_filter (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImethod\fP\fB, int \fIfilters\fP\fB);\fP
+
+\fBvoid png_set_filter_heuristics (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_doublep \fP\fIfilter_weights\fP\fB, png_doublep \fIfilter_costs\fP\fB);\fP
+
+\fBvoid png_set_filter_heuristics_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_fixed_point_p \fP\fIfilter_weights\fP\fB, png_fixed_point_p \fIfilter_costs\fP\fB);\fP
+
+\fBvoid png_set_flush (png_structp \fP\fIpng_ptr\fP\fB, int \fInrows\fP\fB);\fP
+
+\fBvoid png_set_gamma (png_structp \fP\fIpng_ptr\fP\fB, double \fP\fIscreen_gamma\fP\fB, double \fIdefault_file_gamma\fP\fB);\fP
+
+\fBvoid png_set_gamma_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIscreen_gamma\fP\fB, png_uint_32 \fIdefault_file_gamma\fP\fB);\fP
+
+\fBvoid png_set_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fIfile_gamma\fP\fB);\fP
+
+\fBvoid png_set_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIfile_gamma\fP\fB);\fP
+
+\fBvoid png_set_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_gray_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_eXIf (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fIexif\fP\fB);\fP
+
+\fBvoid png_set_eXIf_1 (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fInum_exif\fP\fB, png_bytep \fIexif\fP\fB);\fP
+
+\fBvoid png_set_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fIhist\fP\fB);\fP
+
+\fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_const_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_const_bytep \fP\fIprofile\fP\fB, png_uint_32 \fIproflen\fP\fB);\fP
+
+\fBint png_set_interlace_handling (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_invalid (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fImask\fP\fB);\fP
+
+\fBvoid png_set_invert_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_invert_mono (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwidth\fP\fB, png_uint_32 \fP\fIheight\fP\fB, int \fP\fIbit_depth\fP\fB, int \fP\fIcolor_type\fP\fB, int \fP\fIinterlace_type\fP\fB, int \fP\fIcompression_type\fP\fB, int \fIfilter_type\fP\fB);\fP
+
+\fBvoid png_set_keep_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIkeep\fP\fB, png_bytep \fP\fIchunk_list\fP\fB, int \fInum_chunks\fP\fB);\fP
+
+\fBjmp_buf* png_set_longjmp_fn (png_structp \fP\fIpng_ptr\fP\fB, png_longjmp_ptr \fP\fIlongjmp_fn\fP\fB, size_t \fIjmp_buf_size\fP\fB);\fP
+
+\fBvoid png_set_chunk_malloc_max (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIuser_chunk_cache_max\fP\fB);\fP
+
+\fBvoid png_set_compression_buffer_size (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP
+
+\fBvoid png_set_mem_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fBvoid png_set_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIoffset_x\fP\fB, png_uint_32 \fP\fIoffset_y\fP\fB, int \fIunit_type\fP\fB);\fP
+
+\fBint png_set_option(png_structrp \fP\fIpng_ptr\fP\fB, int \fP\fIoption\fP\fB, int \fIonoff\fP\fB);\fP
+
+\fBvoid png_set_packing (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_packswap (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_palette_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIpurpose\fP\fB, png_int_32 \fP\fIX0\fP\fB, png_int_32 \fP\fIX1\fP\fB, int \fP\fItype\fP\fB, int \fP\fInparams\fP\fB, png_charp \fP\fIunits\fP\fB, png_charpp \fIparams\fP\fB);\fP
+
+\fBvoid png_set_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIres_x\fP\fB, png_uint_32 \fP\fIres_y\fP\fB, int \fIunit_type\fP\fB);\fP
+
+\fBvoid png_set_progressive_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIprogressive_ptr\fP\fB, png_progressive_info_ptr \fP\fIinfo_fn\fP\fB, png_progressive_row_ptr \fP\fIrow_fn\fP\fB, png_progressive_end_ptr \fIend_fn\fP\fB);\fP
+
+\fBvoid png_set_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fInum_palette\fP\fB);\fP
+
+\fBvoid png_set_quantize (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fP\fInum_palette\fP\fB, int \fP\fImaximum_colors\fP\fB, png_uint_16p \fP\fIhistogram\fP\fB, int \fIfull_quantize\fP\fB);\fP
+
+\fBvoid png_set_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fIread_data_fn\fP\fB);\fP
+
+\fBvoid png_set_read_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_read_status_ptr \fIread_row_fn\fP\fB);\fP
+
+\fBvoid png_set_read_user_chunk_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_chunk_ptr\fP\fB, png_user_chunk_ptr \fIread_user_chunk_fn\fP\fB);\fP
+
+\fBvoid png_set_read_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIread_user_transform_fn\fP\fB);\fP
+
+\fBvoid png_set_rgb_to_gray (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIerror_action\fP\fB, double \fP\fIred\fP\fB, double \fIgreen\fP\fB);\fP
+
+\fBvoid png_set_rgb_to_gray_fixed (png_structp \fP\fIpng_ptr\fP\fB, int error_action png_uint_32 \fP\fIred\fP\fB, png_uint_32 \fIgreen\fP\fB);\fP
+
+\fBvoid png_set_rows (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytepp \fIrow_pointers\fP\fB);\fP
+
+\fBvoid png_set_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fIsig_bit\fP\fB);\fP
+
+\fBvoid png_set_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, double \fP\fIwidth\fP\fB, double \fIheight\fP\fB);\fP
+
+\fBvoid png_set_sCAL_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_fixed_point \fP\fIwidth\fP\fB, png_fixed_point \fIheight\fP\fB);\fP
+
+\fBvoid png_set_sCAL_s (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_charp \fP\fIwidth\fP\fB, png_charp \fIheight\fP\fB);\fP
+
+\fBvoid png_set_scale_16 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_shift (png_structp \fP\fIpng_ptr\fP\fB, png_color_8p \fItrue_bits\fP\fB);\fP
+
+\fBvoid png_set_sig_bytes (png_structp \fP\fIpng_ptr\fP\fB, int \fInum_bytes\fP\fB);\fP
+
+\fBvoid png_set_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fP\fIsplt_ptr\fP\fB, int \fInum_spalettes\fP\fB);\fP
+
+\fBvoid png_set_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
+
+\fBvoid png_set_sRGB_gAMA_and_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
+
+\fBvoid png_set_strip_16 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_strip_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_strip_error_numbers (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIstrip_mode\fP\fB);\fP
+
+\fBvoid png_set_swap (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_swap_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_text (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fItext_ptr\fP\fB, int \fInum_text\fP\fB);\fP
+
+\fBvoid png_set_text_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
+
+\fBvoid png_set_text_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
+
+\fBvoid png_set_text_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
+
+\fBvoid png_set_text_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
+
+\fBvoid png_set_text_compression_method (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod\fP\fB);\fP
+
+\fBvoid png_set_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP
+
+\fBvoid png_set_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fItrans_alpha\fP\fB, int \fP\fInum_trans\fP\fB, png_color_16p \fItrans_color\fP\fB);\fP
+
+\fBvoid png_set_tRNS_to_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_set_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkp \fP\fIunknowns\fP\fB, int \fP\fInum\fP\fB, int \fIlocation\fP\fB);\fP
+
+\fBvoid png_set_unknown_chunk_location (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIchunk\fP\fB, int \fIlocation\fP\fB);\fP
+
+\fBvoid png_set_user_limits (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIuser_width_max\fP\fB, png_uint_32 \fIuser_height_max\fP\fB);\fP
+
+\fBvoid png_set_user_transform_info (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_transform_ptr\fP\fB, int \fP\fIuser_transform_depth\fP\fB, int \fIuser_transform_channels\fP\fB);\fP
+
+\fBvoid png_set_write_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fP\fIwrite_data_fn\fP\fB, png_flush_ptr \fIoutput_flush_fn\fP\fB);\fP
+
+\fBvoid png_set_write_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_write_status_ptr \fIwrite_row_fn\fP\fB);\fP
+
+\fBvoid png_set_write_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIwrite_user_transform_fn\fP\fB);\fP
+
+\fBint png_sig_cmp (png_bytep \fP\fIsig\fP\fB, size_t \fP\fIstart\fP\fB, size_t \fInum_to_check\fP\fB);\fP
+
+\fBvoid png_start_read_image (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
+
+\fBvoid png_write_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_bytep \fP\fIdata\fP\fB, size_t \fIlength\fP\fB);\fP
+
+\fBvoid png_write_chunk_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, size_t \fIlength\fP\fB);\fP
+
+\fBvoid png_write_chunk_end (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_write_chunk_start (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fBvoid png_write_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_write_flush (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_write_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
+
+\fBvoid png_write_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_write_info_before_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_write_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
+
+\fBvoid png_write_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fBvoid png_write_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
+
+\fBvoid png_write_sig (png_structp \fIpng_ptr\fP\fB);\fP
+
+.SH DESCRIPTION
+The
+.I libpng
+library supports encoding, decoding, and various manipulations of
+the Portable Network Graphics (PNG) format image files.  It uses the
+.IR zlib(3)
+compression library.
+Following is a copy of the libpng-manual.txt file that accompanies libpng.
+
+.SH LIBPNG.TXT
+libpng-manual.txt - A description on how to use and modify libpng
+
+ Copyright (c) 2018-2019 Cosmin Truta
+ Copyright (c) 1998-2018 Glenn Randers-Pehrson
+
+ This document is released under the libpng license.
+ For conditions of distribution and use, see the disclaimer
+ and license in png.h
+
+ Based on:
+
+ libpng version 1.6.36, December 2018, through 1.6.37 - April 2019
+ Updated and distributed by Cosmin Truta
+ Copyright (c) 2018-2019 Cosmin Truta
+
+ libpng versions 0.97, January 1998, through 1.6.35 - July 2018
+ Updated and distributed by Glenn Randers-Pehrson
+ Copyright (c) 1998-2018 Glenn Randers-Pehrson
+
+ libpng 1.0 beta 6 - version 0.96 - May 28, 1997
+ Updated and distributed by Andreas Dilger
+ Copyright (c) 1996, 1997 Andreas Dilger
+
+ libpng 1.0 beta 2 - version 0.88 - January 26, 1996
+ For conditions of distribution and use, see copyright
+ notice in png.h. Copyright (c) 1995, 1996 Guy Eric
+ Schalnat, Group 42, Inc.
+
+ Updated/rewritten per request in the libpng FAQ
+ Copyright (c) 1995, 1996 Frank J. T. Wojcik
+ December 18, 1995 & January 20, 1996
+
+ TABLE OF CONTENTS
+
+    I. Introduction
+   II. Structures
+  III. Reading
+   IV. Writing
+    V. Simplified API
+   VI. Modifying/Customizing libpng
+  VII. MNG support
+ VIII. Changes to Libpng from version 0.88
+   IX. Changes to Libpng from version 1.0.x to 1.2.x
+    X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+   XI. Changes to Libpng from version 1.4.x to 1.5.x
+  XII. Changes to Libpng from version 1.5.x to 1.6.x
+ XIII. Detecting libpng
+  XIV. Source code repository
+   XV. Coding style
+
+.SH I. Introduction
+
+This file describes how to use and modify the PNG reference library
+(known as libpng) for your own use.  In addition to this
+file, example.c is a good starting point for using the library, as
+it is heavily commented and should include everything most people
+will need.  We assume that libpng is already installed; see the
+INSTALL file for instructions on how to configure and install libpng.
+
+For examples of libpng usage, see the files "example.c", "pngtest.c",
+and the files in the "contrib" directory, all of which are included in
+the libpng distribution.
+
+Libpng was written as a companion to the PNG specification, as a way
+of reducing the amount of time and effort it takes to support the PNG
+file format in application programs.
+
+The PNG specification (second edition), November 2003, is available as
+a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
+<https://www.w3.org/TR/2003/REC-PNG-20031110/>.
+The W3C and ISO documents have identical technical content.
+
+The PNG-1.2 specification is available at
+<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
+It is technically equivalent
+to the PNG specification (second edition) but has some additional material.
+
+The PNG-1.0 specification is available as RFC 2083 at
+<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
+W3C Recommendation at <https://www.w3.org/TR/REC-png-961001>.
+
+Some additional chunks are described in the special-purpose public chunks
+documents at <http://www.libpng.org/pub/png/spec/register/>
+
+Other information
+about PNG, and the latest version of libpng, can be found at the PNG home
+page, <http://www.libpng.org/pub/png/>.
+
+Most users will not have to modify the library significantly; advanced
+users may want to modify it more.  All attempts were made to make it as
+complete as possible, while keeping the code easy to understand.
+Currently, this library only supports C.  Support for other languages
+is being considered.
+
+Libpng has been designed to handle multiple sessions at one time,
+to be easily modifiable, to be portable to the vast majority of
+machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
+to use.  The ultimate goal of libpng is to promote the acceptance of
+the PNG file format in whatever way possible.  While there is still
+work to be done (see the TODO file), libpng should cover the
+majority of the needs of its users.
+
+Libpng uses zlib for its compression and decompression of PNG files.
+Further information about zlib, and the latest version of zlib, can
+be found at the zlib home page, <https://zlib.net/>.
+The zlib compression utility is a general purpose utility that is
+useful for more than PNG files, and can be used without libpng.
+See the documentation delivered with zlib for more details.
+You can usually find the source files for the zlib utility wherever you
+find the libpng source files.
+
+Libpng is thread safe, provided the threads are using different
+instances of the structures.  Each thread should have its own
+png_struct and png_info instances, and thus its own image.
+Libpng does not protect itself against two threads using the
+same instance of a structure.
+
+.SH II. Structures
+
+There are two main structures that are important to libpng, png_struct
+and png_info.  Both are internal structures that are no longer exposed
+in the libpng interface (as of libpng 1.5.0).
+
+The png_info structure is designed to provide information about the
+PNG file.  At one time, the fields of png_info were intended to be
+directly accessible to the user.  However, this tended to cause problems
+with applications using dynamically loaded libraries, and as a result
+a set of interface functions for png_info (the png_get_*() and png_set_*()
+functions) was developed, and direct access to the png_info fields was
+deprecated..
+
+The png_struct structure is the object used by the library to decode a
+single image.  As of 1.5.0 this structure is also not exposed.
+
+Almost all libpng APIs require a pointer to a png_struct as the first argument.
+Many (in particular the png_set and png_get APIs) also require a pointer
+to png_info as the second argument.  Some application visible macros
+defined in png.h designed for basic data access (reading and writing
+integers in the PNG format) don't take a png_info pointer, but it's almost
+always safe to assume that a (png_struct*) has to be passed to call an API
+function.
+
+You can have more than one png_info structure associated with an image,
+as illustrated in pngtest.c, one for information valid prior to the
+IDAT chunks and another (called "end_info" below) for things after them.
+
+The png.h header file is an invaluable reference for programming with libpng.
+And while I'm on the topic, make sure you include the libpng header file:
+
+#include <png.h>
+
+and also (as of libpng-1.5.0) the zlib header file, if you need it:
+
+#include <zlib.h>
+
+.SS Types
+
+The png.h header file defines a number of integral types used by the
+APIs.  Most of these are fairly obvious; for example types corresponding
+to integers of particular sizes and types for passing color values.
+
+One exception is how non-integral numbers are handled.  For application
+convenience most APIs that take such numbers have C (double) arguments;
+however, internally PNG, and libpng, use 32 bit signed integers and encode
+the value by multiplying by 100,000.  As of libpng 1.5.0 a convenience
+macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
+which is simply (png_int_32).
+
+All APIs that take (double) arguments also have a matching API that
+takes the corresponding fixed point integer arguments.  The fixed point
+API has the same name as the floating point one with "_fixed" appended.
+The actual range of values permitted in the APIs is frequently less than
+the full range of (png_fixed_point) (\-21474 to +21474).  When APIs require
+a non-negative argument the type is recorded as png_uint_32 above.  Consult
+the header file and the text below for more information.
+
+Special care must be take with sCAL chunk handling because the chunk itself
+uses non-integral values encoded as strings containing decimal floating point
+numbers.  See the comments in the header file.
+
+.SS Configuration
+
+The main header file function declarations are frequently protected by C
+preprocessing directives of the form:
+
+    #ifdef PNG_feature_SUPPORTED
+    declare-function
+    #endif
+    ...
+    #ifdef PNG_feature_SUPPORTED
+    use-function
+    #endif
+
+The library can be built without support for these APIs, although a
+standard build will have all implemented APIs.  Application programs
+should check the feature macros before using an API for maximum
+portability.  From libpng 1.5.0 the feature macros set during the build
+of libpng are recorded in the header file "pnglibconf.h" and this file
+is always included by png.h.
+
+If you don't need to change the library configuration from the default, skip to
+the next section ("Reading").
+
+Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
+of the build project files in the 'projects' directory simply copy
+scripts/pnglibconf.h.prebuilt to pnglibconf.h.  This means that these build
+systems do not permit easy auto-configuration of the library - they only
+support the default configuration.
+
+The easiest way to make minor changes to the libpng configuration when
+auto-configuration is supported is to add definitions to the command line
+using (typically) CPPFLAGS.  For example:
+
+CPPFLAGS=\-DPNG_NO_FLOATING_ARITHMETIC
+
+will change the internal libpng math implementation for gamma correction and
+other arithmetic calculations to fixed point, avoiding the need for fast
+floating point support.  The result can be seen in the generated pnglibconf.h -
+make sure it contains the changed feature macro setting.
+
+If you need to make more extensive configuration changes - more than one or two
+feature macro settings - you can either add \-DPNG_USER_CONFIG to the build
+command line and put a list of feature macro settings in pngusr.h or you can set
+DFA_XTRA (a makefile variable) to a file containing the same information in the
+form of 'option' settings.
+
+A. Changing pnglibconf.h
+
+A variety of methods exist to build libpng.  Not all of these support
+reconfiguration of pnglibconf.h.  To reconfigure pnglibconf.h it must either be
+rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
+
+Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to
+pnglibconf.h and changing the lines defining the supported features, paying
+very close attention to the 'option' information in scripts/pnglibconf.dfa
+that describes those features and their requirements.  This is easy to get
+wrong.
+
+B. Configuration using DFA_XTRA
+
+Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
+variant such as 'nawk' or 'gawk', is available.  The configure build will
+automatically find an appropriate awk and build pnglibconf.h.
+The scripts/pnglibconf.mak file contains a set of make rules for doing the
+same thing if configure is not used, and many of the makefiles in the scripts
+directory use this approach.
+
+When rebuilding simply write a new file containing changed options and set
+DFA_XTRA to the name of this file.  This causes the build to append the new file
+to the end of scripts/pnglibconf.dfa.  The pngusr.dfa file should contain lines
+of the following forms:
+
+everything = off
+
+This turns all optional features off.  Include it at the start of pngusr.dfa to
+make it easier to build a minimal configuration.  You will need to turn at least
+some features on afterward to enable either reading or writing code, or both.
+
+option feature on
+option feature off
+
+Enable or disable a single feature.  This will automatically enable other
+features required by a feature that is turned on or disable other features that
+require a feature which is turned off.  Conflicting settings will cause an error
+message to be emitted by awk.
+
+setting feature default value
+
+Changes the default value of setting 'feature' to 'value'.  There are a small
+number of settings listed at the top of pnglibconf.h, they are documented in the
+source code.  Most of these values have performance implications for the library
+but most of them have no visible effect on the API.  Some can also be overridden
+from the API.
+
+This method of building a customized pnglibconf.h is illustrated in
+contrib/pngminim/*.  See the "$(PNGCONF):" target in the makefile and
+pngusr.dfa in these directories.
+
+C. Configuration using PNG_USER_CONFIG
+
+If \-DPNG_USER_CONFIG is added to the CPPFLAGS when pnglibconf.h is built,
+the file pngusr.h will automatically be included before the options in
+scripts/pnglibconf.dfa are processed.  Your pngusr.h file should contain only
+macro definitions turning features on or off or setting settings.
+
+Apart from the global setting "everything = off" all the options listed above
+can be set using macros in pngusr.h:
+
+#define PNG_feature_SUPPORTED
+
+is equivalent to:
+
+option feature on
+
+#define PNG_NO_feature
+
+is equivalent to:
+
+option feature off
+
+#define PNG_feature value
+
+is equivalent to:
+
+setting feature default value
+
+Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
+pngusr file you supply override the contents of scripts/pnglibconf.dfa
+
+If confusing or incomprehensible behavior results it is possible to
+examine the intermediate file pnglibconf.dfn to find the full set of
+dependency information for each setting and option.  Simply locate the
+feature in the file and read the C comments that precede it.
+
+This method is also illustrated in the contrib/pngminim/* makefiles and
+pngusr.h.
+
+.SH III. Reading
+
+We'll now walk you through the possible functions to call when reading
+in a PNG file sequentially, briefly explaining the syntax and purpose
+of each one.  See example.c and png.h for more detail.  While
+progressive reading is covered in the next section, you will still
+need some of the functions discussed in this section to read a PNG
+file.
+
+.SS Setup
+
+You will want to do the I/O initialization(*) before you get into libpng,
+so if it doesn't work, you don't have much to undo.  Of course, you
+will also want to insure that you are, in fact, dealing with a PNG
+file.  Libpng provides a simple check to see if a file is a PNG file.
+To use it, pass in the first 1 to 8 bytes of the file to the function
+png_sig_cmp(), and it will return 0 (false) if the bytes match the
+corresponding bytes of the PNG signature, or nonzero (true) otherwise.
+Of course, the more bytes you pass in, the greater the accuracy of the
+prediction.
+
+If you are intending to keep the file pointer open for use in libpng,
+you must ensure you don't read more than 8 bytes from the beginning
+of the file, and you also have to make a call to png_set_sig_bytes()
+with the number of bytes you read from the beginning.  Libpng will
+then only check the bytes (if any) that your program didn't read.
+
+(*): If you are not using the standard I/O functions, you will need
+to replace them with custom functions.  See the discussion under
+Customizing libpng.
+
+    FILE *fp = fopen(file_name, "rb");
+    if (!fp)
+    {
+       return ERROR;
+    }
+
+    if (fread(header, 1, number, fp) != number)
+    {
+       return ERROR;
+    }
+
+    is_png = !png_sig_cmp(header, 0, number);
+    if (!is_png)
+    {
+       return NOT_PNG;
+    }
+
+Next, png_struct and png_info need to be allocated and initialized.  In
+order to ensure that the size of these structures is correct even with a
+dynamically linked libpng, there are functions to initialize and
+allocate the structures.  We also pass the library version, optional
+pointers to error handling functions, and a pointer to a data struct for
+use by the error functions, if necessary (the pointer and functions can
+be NULL if the default error handlers are to be used).  See the section
+on Changes to Libpng below regarding the old initialization functions.
+The structure allocation functions quietly return NULL if they fail to
+create the structure, so your application should check for that.
+
+    png_structp png_ptr = png_create_read_struct
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+       return ERROR;
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+    {
+       png_destroy_read_struct(&png_ptr,
+           (png_infopp)NULL, (png_infopp)NULL);
+       return ERROR;
+    }
+
+If you want to use your own memory allocation routines,
+use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
+png_create_read_struct_2() instead of png_create_read_struct():
+
+    png_structp png_ptr = png_create_read_struct_2
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn, (png_voidp)
+        user_mem_ptr, user_malloc_fn, user_free_fn);
+
+The error handling routines passed to png_create_read_struct()
+and the memory alloc/free routines passed to png_create_struct_2()
+are only necessary if you are not using the libpng supplied error
+handling and memory alloc/free functions.
+
+When libpng encounters an error, it expects to longjmp back
+to your routine.  Therefore, you will need to call setjmp and pass
+your png_jmpbuf(png_ptr).  If you read the file from different
+routines, you will need to update the longjmp buffer every time you enter
+a new routine that will call a png_*() function.
+
+See your documentation of setjmp/longjmp for your compiler for more
+information on setjmp/longjmp.  See the discussion on libpng error
+handling in the Customizing Libpng section below for more information
+on the libpng error handling.  If an error occurs, and libpng longjmp's
+back to your setjmp, you will want to call png_destroy_read_struct() to
+free any memory.
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+           &end_info);
+       fclose(fp);
+       return ERROR;
+    }
+
+Pass (png_infopp)NULL instead of &end_info if you didn't create
+an end_info structure.
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Now you need to set up the input code.  The default for libpng is to
+use the C function fread().  If you use this, you will need to pass a
+valid FILE * in the function png_init_io().  Be sure that the file is
+opened in binary mode.  If you wish to handle reading data in another
+way, you need not call the png_init_io() function, but you must then
+implement the libpng I/O methods discussed in the Customizing Libpng
+section below.
+
+    png_init_io(png_ptr, fp);
+
+If you had previously opened the file and read any of the signature from
+the beginning in order to see if this was a PNG file, you need to let
+libpng know that there are some bytes missing from the start of the file.
+
+    png_set_sig_bytes(png_ptr, number);
+
+You can change the zlib compression buffer size to be used while
+reading compressed data with
+
+    png_set_compression_buffer_size(png_ptr, buffer_size);
+
+where the default size is 8192 bytes.  Note that the buffer size
+is changed immediately and the buffer is reallocated immediately,
+instead of setting a flag to be acted upon later.
+
+If you want CRC errors to be handled in a different manner than
+the default, use
+
+    png_set_crc_action(png_ptr, crit_action, ancil_action);
+
+The values for png_set_crc_action() say how libpng is to handle CRC errors in
+ancillary and critical chunks, and whether to use the data contained
+therein. Starting with libpng-1.6.26, this also governs how an ADLER32 error
+is handled while reading the IDAT chunk. Note that it is impossible to
+"discard" data in a critical chunk.
+
+Choices for (int) crit_action are
+   PNG_CRC_DEFAULT      0  error/quit
+   PNG_CRC_ERROR_QUIT   1  error/quit
+   PNG_CRC_WARN_USE     3  warn/use data
+   PNG_CRC_QUIET_USE    4  quiet/use data
+   PNG_CRC_NO_CHANGE    5  use the current value
+
+Choices for (int) ancil_action are
+   PNG_CRC_DEFAULT      0  error/quit
+   PNG_CRC_ERROR_QUIT   1  error/quit
+   PNG_CRC_WARN_DISCARD 2  warn/discard data
+   PNG_CRC_WARN_USE     3  warn/use data
+   PNG_CRC_QUIET_USE    4  quiet/use data
+   PNG_CRC_NO_CHANGE    5  use the current value
+
+When the setting for crit_action is PNG_CRC_QUIET_USE, the CRC and ADLER32
+checksums are not only ignored, but they are not evaluated.
+
+.SS Setting up callback code
+
+You can set up a callback function to handle any unknown chunks in the
+input stream. You must supply the function
+
+    read_chunk_callback(png_structp png_ptr,
+         png_unknown_chunkp chunk);
+    {
+       /* The unknown chunk structure contains your
+          chunk data, along with similar data for any other
+          unknown chunks: */
+
+           png_byte name[5];
+           png_byte *data;
+           size_t size;
+
+       /* Note that libpng has already taken care of
+          the CRC handling */
+
+       /* put your code here.  Search for your chunk in the
+          unknown chunk structure, process it, and return one
+          of the following: */
+
+       return \-n; /* chunk had an error */
+       return 0; /* did not recognize */
+       return n; /* success */
+    }
+
+(You can give your function another name that you like instead of
+"read_chunk_callback")
+
+To inform libpng about your function, use
+
+    png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
+        read_chunk_callback);
+
+This names not only the callback function, but also a user pointer that
+you can retrieve with
+
+    png_get_user_chunk_ptr(png_ptr);
+
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks which the callback does not handle will be saved when read.  You can
+cause them to be discarded by returning '1' ("handled") instead of '0'.  This
+behavior will change in libpng 1.7 and the default handling set by the
+png_set_keep_unknown_chunks() function, described below, will be used when the
+callback returns 0.  If you want the existing behavior you should set the global
+default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
+versions of libpng and with 1.7.  Libpng 1.6 issues a warning if you keep the
+default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.
+
+At this point, you can set up a callback function that will be
+called after each row has been read, which you can use to control
+a progress meter or the like.  It's demonstrated in pngtest.c.
+You must supply a function
+
+    void read_row_callback(png_structp png_ptr,
+       png_uint_32 row, int pass);
+    {
+      /* put your code here */
+    }
+
+(You can give it another name that you like instead of "read_row_callback")
+
+To inform libpng about your function, use
+
+    png_set_read_status_fn(png_ptr, read_row_callback);
+
+When this function is called the row has already been completely processed and
+the 'row' and 'pass' refer to the next row to be handled.  For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0.  For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes.  Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass\-1'; if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+.SS Unknown-chunk handling
+
+Now you get to set the way the library processes unknown chunks in the
+input PNG stream. Both known and unknown chunks will be read.  Normal
+behavior is that known chunks will be parsed into information in
+various info_ptr members while unknown chunks will be discarded. This
+behavior can be wasteful if your application will never use some known
+chunk types. To change this, you can call:
+
+    png_set_keep_unknown_chunks(png_ptr, keep,
+        chunk_list, num_chunks);
+
+    keep       - 0: default unknown chunk handling
+                 1: ignore; do not keep
+                 2: keep only if safe-to-copy
+                 3: keep even if unsafe-to-copy
+
+               You can use these definitions:
+                 PNG_HANDLE_CHUNK_AS_DEFAULT   0
+                 PNG_HANDLE_CHUNK_NEVER        1
+                 PNG_HANDLE_CHUNK_IF_SAFE      2
+                 PNG_HANDLE_CHUNK_ALWAYS       3
+
+    chunk_list - list of chunks affected (a byte string,
+                 five bytes per chunk, NULL or '\0' if
+                 num_chunks is positive; ignored if
+                 numchunks <= 0).
+
+    num_chunks - number of chunks affected; if 0, all
+                 unknown chunks are affected.  If positive,
+                 only the chunks in the list are affected,
+                 and if negative all unknown chunks and
+                 all known chunks except for the IHDR,
+                 PLTE, tRNS, IDAT, and IEND chunks are
+                 affected.
+
+Unknown chunks declared in this way will be saved as raw data onto a
+list of png_unknown_chunk structures.  If a chunk that is normally
+known to libpng is named in the list, it will be handled as unknown,
+according to the "keep" directive.  If a chunk is named in successive
+instances of png_set_keep_unknown_chunks(), the final instance will
+take precedence.  The IHDR and IEND chunks should not be named in
+chunk_list; if they are, libpng will process them normally anyway.
+If you know that your application will never make use of some particular
+chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below.
+
+Here is an example of the usage of png_set_keep_unknown_chunks(),
+where the private "vpAg" chunk will later be processed by a user chunk
+callback function:
+
+    png_byte vpAg[5]={118, 112,  65, 103, (png_byte) '\0'};
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      png_byte unused_chunks[]=
+      {
+        104,  73,  83,  84, (png_byte) '\0',   /* hIST */
+        105,  84,  88, 116, (png_byte) '\0',   /* iTXt */
+        112,  67,  65,  76, (png_byte) '\0',   /* pCAL */
+        115,  67,  65,  76, (png_byte) '\0',   /* sCAL */
+        115,  80,  76,  84, (png_byte) '\0',   /* sPLT */
+        116,  73,  77,  69, (png_byte) '\0',   /* tIME */
+      };
+    #endif
+
+    ...
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      /* ignore all unknown chunks
+       * (use global setting "2" for libpng16 and earlier):
+       */
+      png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);
+
+      /* except for vpAg: */
+      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
+
+      /* also ignore unused known chunks: */
+      png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
+         (int)(sizeof unused_chunks)/5);
+    #endif
+
+.SS User limits
+
+The PNG specification allows the width and height of an image to be as
+large as 2^(31\-1 (0x7fffffff), or about 2.147 billion rows and columns.
+For safety, libpng imposes a default limit of 1 million rows and columns.
+Larger images will be rejected immediately with a png_error() call. If
+you wish to change these limits, you can use
+
+   png_set_user_limits(png_ptr, width_max, height_max);
+
+to set your own limits (libpng may reject some very wide images
+anyway because of potential buffer overflow conditions).
+
+You should put this statement after you create the PNG structure and
+before calling png_read_info(), png_read_png(), or png_process_data().
+
+When writing a PNG datastream, put this statement before calling
+png_write_info() or png_write_png().
+
+If you need to retrieve the limits that are being applied, use
+
+   width_max = png_get_user_width_max(png_ptr);
+   height_max = png_get_user_height_max(png_ptr);
+
+The PNG specification sets no limit on the number of ancillary chunks
+allowed in a PNG datastream.  By default, libpng imposes a limit of
+a total of 1000 sPLT, tEXt, iTXt, zTXt, and unknown chunks to be stored.
+If you have set up both info_ptr and end_info_ptr, the limit applies
+separately to each.  You can change the limit on the total number of such
+chunks that will be stored, with
+
+   png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
+
+where 0x7fffffffL means unlimited.  You can retrieve this limit with
+
+   chunk_cache_max = png_get_chunk_cache_max(png_ptr);
+
+Libpng imposes a limit of 8 Megabytes (8,000,000 bytes) on the amount of
+memory that any chunk other than IDAT can occupy, originally or when
+decompressed (prior to libpng-1.6.32 the limit was only applied to compressed
+chunks after decompression). You can change this limit with
+
+   png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
+
+and you can retrieve the limit with
+
+   chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
+
+Any chunks that would cause either of these limits to be exceeded will
+be ignored.
+
+.SS Information about your system
+
+If you intend to display the PNG or to incorporate it in other image data you
+need to tell libpng information about your display or drawing surface so that
+libpng can convert the values in the image to match the display.
+
+From libpng-1.5.4 this information can be set before reading the PNG file
+header.  In earlier versions png_set_gamma() existed but behaved incorrectly if
+called before the PNG file header had been read and png_set_alpha_mode() did not
+exist.
+
+If you need to support versions prior to libpng-1.5.4 test the version number
+as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures
+described in the appropriate manual page.
+
+You give libpng the encoding expected by your system expressed as a 'gamma'
+value.  You can also specify a default encoding for the PNG file in
+case the required information is missing from the file.  By default libpng
+assumes that the PNG data matches your system, to keep this default call:
+
+   png_set_gamma(png_ptr, screen_gamma, output_gamma);
+
+or you can use the fixed point equivalent:
+
+   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma,
+      PNG_FP_1*output_gamma);
+
+If you don't know the gamma for your system it is probably 2.2 - a good
+approximation to the IEC standard for display systems (sRGB).  If images are
+too contrasty or washed out you got the value wrong - check your system
+documentation!
+
+Many systems permit the system gamma to be changed via a lookup table in the
+display driver, a few systems, including older Macs, change the response by
+default.  As of 1.5.4 three special values are available to handle common
+situations:
+
+   PNG_DEFAULT_sRGB: Indicates that the system conforms to the
+                     IEC 61966-2-1 standard.  This matches almost
+                     all systems.
+   PNG_GAMMA_MAC_18: Indicates that the system is an older
+                     (pre Mac OS 10.6) Apple Macintosh system with
+                     the default settings.
+   PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates
+                     that the system expects data with no gamma
+                     encoding.
+
+You would use the linear (unencoded) value if you need to process the pixel
+values further because this avoids the need to decode and re-encode each
+component value whenever arithmetic is performed.  A lot of graphics software
+uses linear values for this reason, often with higher precision component values
+to preserve overall accuracy.
+
+
+The output_gamma value expresses how to decode the output values, not how
+they are encoded.  The values used correspond to the normal numbers used to
+describe the overall gamma of a computer display system; for example 2.2 for
+an sRGB conformant system.  The values are scaled by 100000 in the _fixed
+version of the API (so 220000 for sRGB.)
+
+The inverse of the value is always used to provide a default for the PNG file
+encoding if it has no gAMA chunk and if png_set_gamma() has not been called
+to override the PNG gamma information.
+
+When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
+opaque pixels however pixels with lower alpha values are not encoded,
+regardless of the output gamma setting.
+
+When the standard Porter Duff handling is requested with mode 1 the output
+encoding is set to be linear and the output_gamma value is only relevant
+as a default for input data that has no gamma information.  The linear output
+encoding will be overridden if png_set_gamma() is called - the results may be
+highly unexpected!
+
+The following numbers are derived from the sRGB standard and the research
+behind it.  sRGB is defined to be approximated by a PNG gAMA chunk value of
+0.45455 (1/2.2) for PNG.  The value implicitly includes any viewing
+correction required to take account of any differences in the color
+environment of the original scene and the intended display environment; the
+value expresses how to *decode* the image for display, not how the original
+data was *encoded*.
+
+sRGB provides a peg for the PNG standard by defining a viewing environment.
+sRGB itself, and earlier TV standards, actually use a more complex transform
+(a linear portion then a gamma 2.4 power law) than PNG can express.  (PNG is
+limited to simple power laws.)  By saying that an image for direct display on
+an sRGB conformant system should be stored with a gAMA chunk value of 45455
+(11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
+makes it possible to derive values for other display systems and
+environments.
+
+The Mac value is deduced from the sRGB based on an assumption that the actual
+extra viewing correction used in early Mac display systems was implemented as
+a power 1.45 lookup table.
+
+Any system where a programmable lookup table is used or where the behavior of
+the final display device characteristics can be changed requires system
+specific code to obtain the current characteristic.  However this can be
+difficult and most PNG gamma correction only requires an approximate value.
+
+By default, if png_set_alpha_mode() is not called, libpng assumes that all
+values are unencoded, linear, values and that the output device also has a
+linear characteristic.  This is only very rarely correct - it is invariably
+better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
+default if you don't know what the right answer is!
+
+The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
+10.6) which used a correction table to implement a somewhat lower gamma on an
+otherwise sRGB system.
+
+Both these values are reserved (not simple gamma values) in order to allow
+more precise correction internally in the future.
+
+NOTE: the values can be passed to either the fixed or floating
+point APIs, but the floating point API will also accept floating point
+values.
+
+The second thing you may need to tell libpng about is how your system handles
+alpha channel information.  Some, but not all, PNG files contain an alpha
+channel.  To display these files correctly you need to compose the data onto a
+suitable background, as described in the PNG specification.
+
+Libpng only supports composing onto a single color (using png_set_background;
+see below).  Otherwise you must do the composition yourself and, in this case,
+you may need to call png_set_alpha_mode:
+
+   #if PNG_LIBPNG_VER >= 10504
+      png_set_alpha_mode(png_ptr, mode, screen_gamma);
+   #else
+      png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma);
+   #endif
+
+The screen_gamma value is the same as the argument to png_set_gamma; however,
+how it affects the output depends on the mode.  png_set_alpha_mode() sets the
+file gamma default to 1/screen_gamma, so normally you don't need to call
+png_set_gamma.  If you need different defaults call png_set_gamma() before
+png_set_alpha_mode() - if you call it after it will override the settings made
+by png_set_alpha_mode().
+
+The mode is as follows:
+
+    PNG_ALPHA_PNG: The data is encoded according to the PNG
+specification.  Red, green and blue, or gray, components are
+gamma encoded color values and are not premultiplied by the
+alpha value.  The alpha value is a linear measure of the
+contribution of the pixel to the corresponding final output pixel.
+
+You should normally use this format if you intend to perform
+color correction on the color values; most, maybe all, color
+correction software has no handling for the alpha channel and,
+anyway, the math to handle pre-multiplied component values is
+unnecessarily complex.
+
+Before you do any arithmetic on the component values you need
+to remove the gamma encoding and multiply out the alpha
+channel.  See the PNG specification for more detail.  It is
+important to note that when an image with an alpha channel is
+scaled, linear encoded, pre-multiplied component values must
+be used!
+
+The remaining modes assume you don't need to do any further color correction or
+that if you do, your color correction software knows all about alpha (it
+probably doesn't!).  They 'associate' the alpha with the color information by
+storing color channel values that have been scaled by the alpha.  The
+advantage is that the color channels can be resampled (the image can be
+scaled) in this form.  The disadvantage is that normal practice is to store
+linear, not (gamma) encoded, values and this requires 16-bit channels for
+still images rather than the 8-bit channels that are just about sufficient if
+gamma encoding is used.  In addition all non-transparent pixel values,
+including completely opaque ones, must be gamma encoded to produce the final
+image.  These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+described below (the latter being the two common names for associated alpha
+color channels). Note that PNG files always contain non-associated color
+channels; png_set_alpha_mode() with one of the modes causes the decoder to
+convert the pixels to an associated form before returning them to your
+application. 
+
+Since it is not necessary to perform arithmetic on opaque color values so
+long as they are not to be resampled and are in the final color space it is
+possible to optimize the handling of alpha by storing the opaque pixels in
+the PNG format (adjusted for the output color space) while storing partially
+opaque pixels in the standard, linear, format.  The accuracy required for
+standard alpha composition is relatively low, because the pixels are
+isolated, therefore typically the accuracy loss in storing 8-bit linear
+values is acceptable.  (This is not true if the alpha channel is used to
+simulate transparency over large areas - use 16 bits or the PNG mode in
+this case!)  This is the 'OPTIMIZED' mode.  For this mode a pixel is
+treated as opaque only if the alpha value is equal to the maximum value.
+
+    PNG_ALPHA_STANDARD:  The data libpng produces is encoded in the
+standard way assumed by most correctly written graphics software.
+The gamma encoding will be removed by libpng and the
+linear component values will be pre-multiplied by the
+alpha channel.
+
+With this format the final image must be re-encoded to
+match the display gamma before the image is displayed.
+If your system doesn't do that, yet still seems to
+perform arithmetic on the pixels without decoding them,
+it is broken - check out the modes below.
+
+With PNG_ALPHA_STANDARD libpng always produces linear
+component values, whatever screen_gamma you supply.  The
+screen_gamma value is, however, used as a default for
+the file gamma if the PNG file has no gamma information.
+
+If you call png_set_gamma() after png_set_alpha_mode() you
+will override the linear encoding.  Instead the
+pre-multiplied pixel values will be gamma encoded but
+the alpha channel will still be linear.  This may
+actually match the requirements of some broken software,
+but it is unlikely.
+
+While linear 8-bit data is often used it has
+insufficient precision for any image with a reasonable
+dynamic range.  To avoid problems, and if your software
+supports it, use png_set_expand_16() to force all
+components to 16 bits.
+
+    PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD
+except that completely opaque pixels are gamma encoded according to
+the screen_gamma value.  Pixels with alpha less than 1.0
+will still have linear components.
+
+Use this format if you have control over your
+compositing software and so don't do other arithmetic
+(such as scaling) on the data you get from libpng.  Your
+compositing software can simply copy opaque pixels to
+the output but still has linear values for the
+non-opaque pixels.
+
+In normal compositing, where the alpha channel encodes
+partial pixel coverage (as opposed to broad area
+translucency), the inaccuracies of the 8-bit
+representation of non-opaque pixels are irrelevant.
+
+You can also try this format if your software is broken;
+it might look better.
+
+    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD; however, all component
+values, including the alpha channel are gamma encoded.  This is
+broken because, in practice, no implementation that uses this choice
+correctly undoes the encoding before handling alpha composition.  Use this
+choice only if other serious errors in the software or hardware you use
+mandate it.  In most cases of broken software or hardware the bug in the
+final display manifests as a subtle halo around composited parts of the
+image.  You may not even perceive this as a halo; the composited part of
+the image may simply appear separate from the background, as though it had
+been cut out of paper and pasted on afterward.
+
+If you don't have to deal with bugs in software or hardware, or if you can fix
+them, there are three recommended ways of using png_set_alpha_mode():
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
+       screen_gamma);
+
+You can do color correction on the result (libpng does not currently
+support color correction internally).  When you handle the alpha channel
+you need to undo the gamma encoding and multiply out the alpha.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
+       screen_gamma);
+   png_set_expand_16(png_ptr);
+
+If you are using the high level interface, don't call png_set_expand_16();
+instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
+
+With this mode you can't do color correction, but you can do arithmetic,
+including composition and scaling, on the data without further processing.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
+       screen_gamma);
+
+You can avoid the expansion to 16-bit components with this mode, but you
+lose the ability to scale the image or perform other linear arithmetic.
+All you can do is compose the result onto a matching output.  Since this
+mode is libpng-specific you also need to write your own composition
+software.
+
+The following are examples of calls to png_set_alpha_mode to achieve the
+required overall gamma correction and, where necessary, alpha
+premultiplication.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+
+Choices for the alpha_mode are
+
+    PNG_ALPHA_PNG           0 /* according to the PNG standard */
+    PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
+    PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
+    PNG_ALPHA_PREMULTIPLIED 1 /* as above */
+    PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
+    PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
+
+PNG_ALPHA_PNG is the default libpng handling of the alpha channel. It is not
+pre-multiplied into the color components. In addition the call states
+that the output is for a sRGB system and causes all PNG files without gAMA
+chunks to be assumed to be encoded using sRGB.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+In this case the output is assumed to be something like an sRGB conformant
+display preceded by a power-law lookup table of power 1.45.  This is how
+early Mac systems behaved.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+
+This is the classic Jim Blinn approach and will work in academic
+environments where everything is done by the book.  It has the shortcoming
+of assuming that input PNG data with no gamma information is linear - this
+is unlikely to be correct unless the PNG files were generated locally.
+Most of the time the output precision will be so low as to show
+significant banding in dark areas of the image.
+
+    png_set_expand_16(pp);
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+
+This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
+are assumed to have the sRGB encoding if not marked with a gamma value and
+the output is always 16 bits per component.  This permits accurate scaling
+and processing of the data.  If you know that your input PNG files were
+generated locally you might need to replace PNG_DEFAULT_sRGB with the
+correct value for your system.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+
+If you just need to composite the PNG image onto an existing background
+and if you control the code that does this you can use the optimization
+setting.  In this case you just copy completely opaque pixels to the
+output.  For pixels that are not completely transparent (you just skip
+those) you do the composition math using png_composite or png_composite_16
+below then encode the resultant 8-bit or 16-bit values to match the output
+encoding.
+
+    Other cases
+
+If neither the PNG nor the standard linear encoding work for you because
+of the software or hardware you use then you have a big problem.  The PNG
+case will probably result in halos around the image.  The linear encoding
+will probably result in a washed out, too bright, image (it's actually too
+contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
+substantially reduce the halos.  Alternatively try:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+
+This option will also reduce the halos, but there will be slight dark
+halos round the opaque parts of the image where the background is light.
+In the OPTIMIZED mode the halos will be light halos where the background
+is dark.  Take your pick - the halos are unavoidable unless you can get
+your hardware/software fixed!  (The OPTIMIZED approach is slightly
+faster.)
+
+When the default gamma of PNG files doesn't match the output gamma.
+If you have PNG files with no gamma information png_set_alpha_mode allows
+you to provide a default gamma, but it also sets the output gamma to the
+matching value.  If you know your PNG files have a gamma that doesn't
+match the output you can take advantage of the fact that
+png_set_alpha_mode always sets the output gamma but only sets the PNG
+default if it is not already set:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+The first call sets both the default and the output gamma values, the
+second call overrides the output gamma without changing the default.  This
+is easier than achieving the same effect with png_set_gamma.  You must use
+PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+fire if more than one call to png_set_alpha_mode and png_set_background is
+made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+are ignored.
+
+If you don't need, or can't handle, the alpha channel you can call
+png_set_background() to remove it by compositing against a fixed color.  Don't
+call png_set_strip_alpha() to do this - it will leave spurious pixel values in
+transparent parts of this image.
+
+   png_set_background(png_ptr, &background_color,
+       PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
+
+The background_color is an RGB or grayscale value according to the data format
+libpng will produce for you.  Because you don't yet know the format of the PNG
+file, if you call png_set_background at this point you must arrange for the
+format produced by libpng to always have 8-bit or 16-bit components and then
+store the color as an 8-bit or 16-bit color as appropriate.  The color contains
+separate gray and RGB component values, so you can let libpng produce gray or
+RGB output according to the input format, but low bit depth grayscale images
+must always be converted to at least 8-bit format.  (Even though low bit depth
+grayscale images can't have an alpha channel they can have a transparent
+color!)
+
+You set the transforms you need later, either as flags to the high level
+interface or libpng API calls for the low level interface.  For reference the
+settings and API calls required are:
+
+8-bit values:
+   PNG_TRANSFORM_SCALE_16 | PNG_EXPAND
+   png_set_expand(png_ptr); png_set_scale_16(png_ptr);
+
+   If you must get exactly the same inaccurate results
+   produced by default in versions prior to libpng-1.5.4,
+   use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr)
+   instead.
+
+16-bit values:
+   PNG_TRANSFORM_EXPAND_16
+   png_set_expand_16(png_ptr);
+
+In either case palette image data will be expanded to RGB.  If you just want
+color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
+to the list.
+
+Calling png_set_background before the PNG file header is read will not work
+prior to libpng-1.5.4.  Because the failure may result in unexpected warnings or
+errors it is therefore much safer to call png_set_background after the head has
+been read.  Unfortunately this means that prior to libpng-1.5.4 it cannot be
+used with the high level interface.
+
+.SS The high-level read interface
+
+At this point there are two ways to proceed; through the high-level
+read interface, or through a sequence of low-level read operations.
+You can use the high-level interface if (a) you are willing to read
+the entire image into memory, and (b) the input transformations
+you want to do are limited to the following set:
+
+    PNG_TRANSFORM_IDENTITY      No transformation
+    PNG_TRANSFORM_SCALE_16      Strip 16-bit samples to
+                                8-bit accurately
+    PNG_TRANSFORM_STRIP_16      Chop 16-bit samples to
+                                8-bit less accurately
+    PNG_TRANSFORM_STRIP_ALPHA   Discard the alpha channel
+    PNG_TRANSFORM_PACKING       Expand 1, 2 and 4-bit
+                                samples to bytes
+    PNG_TRANSFORM_PACKSWAP      Change order of packed
+                                pixels to LSB first
+    PNG_TRANSFORM_EXPAND        Perform set_expand()
+    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
+    PNG_TRANSFORM_SHIFT         Normalize pixels to the
+                                sBIT depth
+    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
+                                to BGRA
+    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
+                                to AG
+    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
+                                to transparency
+    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
+    PNG_TRANSFORM_GRAY_TO_RGB   Expand grayscale samples
+                                to RGB (or GA to RGBA)
+    PNG_TRANSFORM_EXPAND_16     Expand samples to 16 bits
+
+(This excludes setting a background color, doing gamma transformation,
+quantizing, and setting filler.)  If this is the case, simply do this:
+
+    png_read_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some
+set of transformation flags.  This call is equivalent to png_read_info(),
+followed the set of transformations indicated by the transform mask,
+then png_read_image(), and finally png_read_end().
+
+(The final parameter of this call is not yet used.  Someday it might point
+to transformation parameters required by some future input transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_read_png().
+
+After you have called png_read_png(), you can retrieve the image data
+with
+
+   row_pointers = png_get_rows(png_ptr, info_ptr);
+
+where row_pointers is an array of pointers to the pixel data for each row:
+
+   png_bytep row_pointers[height];
+
+If you know your image size and pixel size ahead of time, you can allocate
+row_pointers prior to calling png_read_png() with
+
+   if (height > PNG_UINT_32_MAX/(sizeof (png_byte)))
+      png_error (png_ptr,
+          "Image is too tall to process in memory");
+
+   if (width > PNG_UINT_32_MAX/pixel_size)
+      png_error (png_ptr,
+          "Image is too wide to process in memory");
+
+   row_pointers = png_malloc(png_ptr,
+       height*(sizeof (png_bytep)));
+
+   for (int i=0; i<height, i++)
+      row_pointers[i]=NULL;  /* security precaution */
+
+   for (int i=0; i<height, i++)
+      row_pointers[i]=png_malloc(png_ptr,
+          width*pixel_size);
+
+   png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+Alternatively you could allocate your image in one big block and define
+row_pointers[i] to point into the proper places in your block, but first
+be sure that your platform is able to allocate such a large buffer:
+
+   /* Guard against integer overflow */
+   if (height > PNG_SIZE_MAX/(width*pixel_size)) {
+        png_error(png_ptr,"image_data buffer would be too large");
+   }
+
+   png_bytep buffer=png_malloc(png_ptr,height*width*pixel_size);
+
+   for (int i=0; i<height, i++)
+      row_pointers[i]=buffer+i*width*pixel_size;
+
+   png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+If you use png_set_rows(), the application is responsible for freeing
+row_pointers (and row_pointers[i], if they were separately allocated).
+
+If you don't allocate row_pointers ahead of time, png_read_png() will
+do it, and it'll be free'ed by libpng when you call png_destroy_*().
+
+.SS The low-level read interface
+
+If you are going the low-level route, you are now ready to read all
+the file information up to the actual image data.  You do this with a
+call to png_read_info().
+
+    png_read_info(png_ptr, info_ptr);
+
+This will process all chunks up to but not including the image data.
+
+This also copies some of the data from the PNG file into the decode structure
+for use in later transformations.  Important information copied in is:
+
+1) The PNG file gamma from the gAMA chunk.  This overwrites the default value
+provided by an earlier call to png_set_gamma or png_set_alpha_mode.
+
+2) Prior to libpng-1.5.4 the background color from a bKGd chunk.  This
+damages the information provided by an earlier call to png_set_background
+resulting in unexpected behavior.  Libpng-1.5.4 no longer does this.
+
+3) The number of significant bits in each component value.  Libpng uses this to
+optimize gamma handling by reducing the internal lookup table sizes.
+
+4) The transparent color information from a tRNS chunk.  This can be modified by
+a later call to png_set_tRNS.
+
+.SS Querying the info structure
+
+Functions are used to get the information from the info_ptr once it
+has been read.  Note that these fields may not be completely filled
+in until png_read_end() has read the chunk data following the image.
+
+    png_get_IHDR(png_ptr, info_ptr, &width, &height,
+       &bit_depth, &color_type, &interlace_type,
+       &compression_type, &filter_method);
+
+    width          - holds the width of the image
+                     in pixels (up to 2^31).
+
+    height         - holds the height of the image
+                     in pixels (up to 2^31).
+
+    bit_depth      - holds the bit depth of one of the
+                     image channels.  (valid values are
+                     1, 2, 4, 8, 16 and depend also on
+                     the color_type.  See also
+                     significant bits (sBIT) below).
+
+    color_type     - describes which color/alpha channels
+                         are present.
+                     PNG_COLOR_TYPE_GRAY
+                        (bit depths 1, 2, 4, 8, 16)
+                     PNG_COLOR_TYPE_GRAY_ALPHA
+                        (bit depths 8, 16)
+                     PNG_COLOR_TYPE_PALETTE
+                        (bit depths 1, 2, 4, 8)
+                     PNG_COLOR_TYPE_RGB
+                        (bit_depths 8, 16)
+                     PNG_COLOR_TYPE_RGB_ALPHA
+                        (bit_depths 8, 16)
+
+                     PNG_COLOR_MASK_PALETTE
+                     PNG_COLOR_MASK_COLOR
+                     PNG_COLOR_MASK_ALPHA
+
+    interlace_type - (PNG_INTERLACE_NONE or
+                     PNG_INTERLACE_ADAM7)
+
+    compression_type - (must be PNG_COMPRESSION_TYPE_BASE
+                     for PNG 1.0)
+
+    filter_method  - (must be PNG_FILTER_TYPE_BASE
+                     for PNG 1.0, and can also be
+                     PNG_INTRAPIXEL_DIFFERENCING if
+                     the PNG datastream is embedded in
+                     a MNG-1.0 datastream)
+
+    Any of width, height, color_type, bit_depth,
+    interlace_type, compression_type, or filter_method can
+    be NULL if you are not interested in their values.
+
+    Note that png_get_IHDR() returns 32-bit data into
+    the application's width and height variables.
+    This is an unsafe situation if these are not png_uint_32
+    variables.  In such situations, the
+    png_get_image_width() and png_get_image_height()
+    functions described below are safer.
+
+    width            = png_get_image_width(png_ptr,
+                         info_ptr);
+
+    height           = png_get_image_height(png_ptr,
+                         info_ptr);
+
+    bit_depth        = png_get_bit_depth(png_ptr,
+                         info_ptr);
+
+    color_type       = png_get_color_type(png_ptr,
+                         info_ptr);
+
+    interlace_type   = png_get_interlace_type(png_ptr,
+                         info_ptr);
+
+    compression_type = png_get_compression_type(png_ptr,
+                         info_ptr);
+
+    filter_method    = png_get_filter_type(png_ptr,
+                         info_ptr);
+
+    channels = png_get_channels(png_ptr, info_ptr);
+
+    channels       - number of channels of info for the
+                     color type (valid values are 1 (GRAY,
+                     PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
+                     4 (RGB_ALPHA or RGB + filler byte))
+
+    rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+    rowbytes       - number of bytes needed to hold a row
+                     This value, the bit_depth, color_type,
+                     and the number of channels can change
+                     if you use transforms such as
+                     png_set_expand(). See
+                     png_read_update_info(), below.
+
+    signature = png_get_signature(png_ptr, info_ptr);
+
+    signature      - holds the signature read from the
+                     file (if any).  The data is kept in
+                     the same offset it would be if the
+                     whole signature were read (i.e. if an
+                     application had already read in 4
+                     bytes of signature before starting
+                     libpng, the remaining 4 bytes would
+                     be in signature[4] through signature[7]
+                     (see png_set_sig_bytes())).
+
+These are also important, but their validity depends on whether the chunk
+has been read.  The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
+png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
+data has been read, or zero if it is missing.  The parameters to the
+png_get_<chunk> are set directly if they are simple data types, or a
+pointer into the info_ptr is returned for any complex types.
+
+The colorspace data from gAMA, cHRM, sRGB, iCCP, and sBIT chunks
+is simply returned to give the application information about how the
+image was encoded.  Libpng itself only does transformations using the file
+gamma when combining semitransparent pixels with the background color, and,
+since libpng-1.6.0, when converting between 8-bit sRGB and 16-bit linear pixels
+within the simplified API.  Libpng also uses the file gamma when converting
+RGB to gray, beginning with libpng-1.0.5, if the application calls
+png_set_rgb_to_gray()).
+
+    png_get_PLTE(png_ptr, info_ptr, &palette,
+                     &num_palette);
+
+    palette        - the palette for the file
+                     (array of png_color)
+
+    num_palette    - number of entries in the palette
+
+    png_get_gAMA(png_ptr, info_ptr, &file_gamma);
+    png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
+
+    file_gamma     - the gamma at which the file is
+                     written (PNG_INFO_gAMA)
+
+    int_file_gamma - 100,000 times the gamma at which the
+                     file is written
+
+    png_get_cHRM(png_ptr, info_ptr,  &white_x, &white_y, &red_x,
+                     &red_y, &green_x, &green_y, &blue_x, &blue_y)
+    png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z,
+                     &green_X, &green_Y, &green_Z, &blue_X, &blue_Y,
+                     &blue_Z)
+    png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x,
+                     &int_white_y, &int_red_x, &int_red_y,
+                     &int_green_x, &int_green_y, &int_blue_x,
+                     &int_blue_y)
+    png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y,
+                     &int_red_Z, &int_green_X, &int_green_Y,
+                     &int_green_Z, &int_blue_X, &int_blue_Y,
+                     &int_blue_Z)
+
+    {white,red,green,blue}_{x,y}
+                     A color space encoding specified using the
+                     chromaticities of the end points and the
+                     white point. (PNG_INFO_cHRM)
+
+    {red,green,blue}_{X,Y,Z}
+                     A color space encoding specified using the
+                     encoding end points - the CIE tristimulus
+                     specification of the intended color of the red,
+                     green and blue channels in the PNG RGB data.
+                     The white point is simply the sum of the three
+                     end points. (PNG_INFO_cHRM)
+
+    png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
+
+    srgb_intent -    the rendering intent (PNG_INFO_sRGB)
+                     The presence of the sRGB chunk
+                     means that the pixel data is in the
+                     sRGB color space.  This chunk also
+                     implies specific values of gAMA and
+                     cHRM.
+
+    png_get_iCCP(png_ptr, info_ptr, &name,
+       &compression_type, &profile, &proflen);
+
+    name             - The profile name.
+
+    compression_type - The compression type; always
+                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+                       You may give NULL to this argument to
+                       ignore it.
+
+    profile          - International Color Consortium color
+                       profile data. May contain NULs.
+
+    proflen          - length of profile data in bytes.
+
+    png_get_sBIT(png_ptr, info_ptr, &sig_bit);
+
+    sig_bit        - the number of significant bits for
+                     (PNG_INFO_sBIT) each of the gray,
+                     red, green, and blue channels,
+                     whichever are appropriate for the
+                     given color type (png_color_16)
+
+    png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
+                     &num_trans, &trans_color);
+
+    trans_alpha    - array of alpha (transparency)
+                     entries for palette (PNG_INFO_tRNS)
+
+    num_trans      - number of transparent entries
+                     (PNG_INFO_tRNS)
+
+    trans_color    - graylevel or color sample values of
+                     the single transparent color for
+                     non-paletted images (PNG_INFO_tRNS)
+
+    png_get_eXIf_1(png_ptr, info_ptr, &num_exif, &exif);
+                     (PNG_INFO_eXIf)
+
+    exif           - Exif profile (array of png_byte)
+
+    png_get_hIST(png_ptr, info_ptr, &hist);
+                     (PNG_INFO_hIST)
+
+    hist           - histogram of palette (array of
+                     png_uint_16)
+
+    png_get_tIME(png_ptr, info_ptr, &mod_time);
+
+    mod_time       - time image was last modified
+                    (PNG_VALID_tIME)
+
+    png_get_bKGD(png_ptr, info_ptr, &background);
+
+    background     - background color (of type
+                     png_color_16p) (PNG_VALID_bKGD)
+                     valid 16-bit red, green and blue
+                     values, regardless of color_type
+
+    num_comments   = png_get_text(png_ptr, info_ptr,
+                     &text_ptr, &num_text);
+
+    num_comments   - number of comments
+
+    text_ptr       - array of png_text holding image
+                     comments
+
+    text_ptr[i].compression - type of compression used
+                 on "text" PNG_TEXT_COMPRESSION_NONE
+                           PNG_TEXT_COMPRESSION_zTXt
+                           PNG_ITXT_COMPRESSION_NONE
+                           PNG_ITXT_COMPRESSION_zTXt
+
+    text_ptr[i].key   - keyword for comment.  Must contain
+                         1-79 characters.
+
+    text_ptr[i].text  - text comments for current
+                         keyword.  Can be empty.
+
+    text_ptr[i].text_length - length of text string,
+                 after decompression, 0 for iTXt
+
+    text_ptr[i].itxt_length - length of itxt string,
+                 after decompression, 0 for tEXt/zTXt
+
+    text_ptr[i].lang  - language of comment (empty
+                         string for unknown).
+
+    text_ptr[i].lang_key  - keyword in UTF-8
+                         (empty string for unknown).
+
+    Note that the itxt_length, lang, and lang_key
+    members of the text_ptr structure only exist when the
+    library is built with iTXt chunk support.  Prior to
+    libpng-1.4.0 the library was built by default without
+    iTXt support. Also note that when iTXt is supported,
+    they contain NULL pointers when the "compression"
+    field contains PNG_TEXT_COMPRESSION_NONE or
+    PNG_TEXT_COMPRESSION_zTXt.
+
+    num_text       - number of comments (same as
+                     num_comments; you can put NULL here
+                     to avoid the duplication)
+
+    Note while png_set_text() will accept text, language,
+    and translated keywords that can be NULL pointers, the
+    structure returned by png_get_text will always contain
+    regular zero-terminated C strings.  They might be
+    empty strings but they will never be NULL pointers.
+
+    num_spalettes = png_get_sPLT(png_ptr, info_ptr,
+       &palette_ptr);
+
+    num_spalettes  - number of sPLT chunks read.
+
+    palette_ptr    - array of palette structures holding
+                     contents of one or more sPLT chunks
+                     read.
+
+    png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
+       &unit_type);
+
+    offset_x       - positive offset from the left edge
+                     of the screen (can be negative)
+
+    offset_y       - positive offset from the top edge
+                     of the screen (can be negative)
+
+    unit_type      - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+    png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
+       &unit_type);
+
+    res_x          - pixels/unit physical resolution in
+                     x direction
+
+    res_y          - pixels/unit physical resolution in
+                     x direction
+
+    unit_type      - PNG_RESOLUTION_UNKNOWN,
+                     PNG_RESOLUTION_METER
+
+    png_get_sCAL(png_ptr, info_ptr, &unit, &width,
+       &height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+
+    height      - height of a pixel in physical scale units
+                 (width and height are doubles)
+
+    png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
+       &height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+                  (expressed as a string)
+
+    height      - height of a pixel in physical scale units
+                 (width and height are strings like "2.54")
+
+    num_unknown_chunks = png_get_unknown_chunks(png_ptr,
+       info_ptr, &unknowns)
+
+    unknowns          - array of png_unknown_chunk
+                        structures holding unknown chunks
+
+    unknowns[i].name  - name of unknown chunk
+
+    unknowns[i].data  - data of unknown chunk
+
+    unknowns[i].size  - size of unknown chunk's data
+
+    unknowns[i].location - position of chunk in file
+
+    The value of "i" corresponds to the order in which the
+    chunks were read from the PNG file or inserted with the
+    png_set_unknown_chunks() function.
+
+    The value of "location" is a bitwise "or" of
+
+         PNG_HAVE_IHDR  (0x01)
+         PNG_HAVE_PLTE  (0x02)
+         PNG_AFTER_IDAT (0x08)
+
+The data from the pHYs chunk can be retrieved in several convenient
+forms:
+
+    res_x = png_get_x_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_y = png_get_y_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_x_and_y = png_get_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_x = png_get_x_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    res_y = png_get_y_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    res_x_and_y = png_get_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
+       info_ptr)
+
+    Each of these returns 0 [signifying "unknown"] if
+       the data is not present or if res_x is 0;
+       res_x_and_y is 0 if res_x != res_y
+
+    Note that because of the way the resolutions are
+       stored internally, the inch conversions won't
+       come out to exactly even number.  For example,
+       72 dpi is stored as 0.28346 pixels/meter, and
+       when this is retrieved it is 71.9988 dpi, so
+       be sure to round the returned value appropriately
+       if you want to display a reasonable-looking result.
+
+The data from the oFFs chunk can be retrieved in several convenient
+forms:
+
+    x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
+
+    y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
+
+    x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
+
+    y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
+
+    Each of these returns 0 [signifying "unknown" if both
+       x and y are 0] if the data is not present or if the
+       chunk is present but the unit is the pixel.  The
+       remark about inexact inch conversions applies here
+       as well, because a value in inches can't always be
+       converted to microns and back without some loss
+       of precision.
+
+For more information, see the
+PNG specification for chunk contents.  Be careful with trusting
+rowbytes, as some of the transformations could increase the space
+needed to hold a row (expand, filler, gray_to_rgb, etc.).
+See png_read_update_info(), below.
+
+A quick word about text_ptr and num_text.  PNG stores comments in
+keyword/text pairs, one pair per chunk, with no limit on the number
+of text chunks, and a 2^31 byte limit on their size.  While there are
+suggested keywords, there is no requirement to restrict the use to these
+strings.  It is strongly suggested that keywords and text be sensible
+to humans (that's the point), so don't use abbreviations.  Non-printing
+symbols are not allowed.  See the PNG specification for more details.
+There is also no requirement to have text after the keyword.
+
+Keywords should be limited to 79 Latin-1 characters without leading or
+trailing spaces, but non-consecutive spaces are allowed within the
+keyword.  It is possible to have the same keyword any number of times.
+The text_ptr is an array of png_text structures, each holding a
+pointer to a language string, a pointer to a keyword and a pointer to
+a text string.  The text string, language code, and translated
+keyword may be empty or NULL pointers.  The keyword/text
+pairs are put into the array in the order that they are received.
+However, some or all of the text chunks may be after the image, so, to
+make sure you have read all the text chunks, don't mess with these
+until after you read the stuff after the image.  This will be
+mentioned again below in the discussion that goes with png_read_end().
+
+.SS Input transformations
+
+After you've read the header information, you can set up the library
+to handle any special transformations of the image data.  The various
+ways to transform the data will be described in the order that they
+should occur.  This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths.
+
+Transformations you request are ignored if they don't have any meaning for a
+particular input data format.  However some transformations can have an effect
+as a result of a previous transformation.  If you specify a contradictory set of
+transformations, for example both adding and removing the alpha channel, you
+cannot predict the final result.
+
+The color used for the transparency values should be supplied in the same
+format/depth as the current image data.  It is stored in the same format/depth
+as the image data in a tRNS chunk, so this is what libpng expects for this data.
+
+The color used for the background value depends on the need_expand argument as
+described below.
+
+Data will be decoded into the supplied row buffers packed into bytes
+unless the library has been told to transform it into another format.
+For example, 4 bit/pixel paletted or grayscale data will be returned
+2 pixels/byte with the leftmost pixel in the high-order bits of the byte,
+unless png_set_packing() is called.  8-bit RGB data will be stored
+in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
+is called to insert filler bytes, either before or after each RGB triplet.
+
+16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
+byte of the color value first, unless png_set_scale_16() is called to
+transform it to regular RGB RGB triplets, or png_set_filler() or
+png_set_add alpha() is called to insert two filler bytes, either before
+or after each RRGGBB triplet.  Similarly, 8-bit or 16-bit grayscale data can
+be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(),
+or png_set_scale_16().
+
+The following code transforms grayscale images of less than 8 to 8 bits,
+changes paletted images to RGB, and adds a full alpha channel if there is
+transparency information in a tRNS chunk.  This is most useful on
+grayscale images with bit depths of 2 or 4 or if there is a multiple-image
+viewing application that wishes to treat all images in the same way.
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_palette_to_rgb(png_ptr);
+
+    if (png_get_valid(png_ptr, info_ptr,
+        PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
+
+    if (color_type == PNG_COLOR_TYPE_GRAY &&
+        bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+The first two functions are actually aliases for png_set_expand(), added
+in libpng version 1.0.4, with the function names expanded to improve code
+readability.  In some future version they may actually do different
+things.
+
+As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
+added.  It expands the sample depth without changing tRNS to alpha.
+
+As of libpng version 1.5.2, png_set_expand_16() was added.  It behaves as
+png_set_expand(); however, the resultant channels have 16 bits rather than 8.
+Use this when the output color or gray channels are made linear to avoid fairly
+severe accuracy loss.
+
+   if (bit_depth < 16)
+      png_set_expand_16(png_ptr);
+
+PNG can have files with 16 bits per channel.  If you only can handle
+8 bits per channel, this will strip the pixels down to 8-bit.
+
+    if (bit_depth == 16)
+#if PNG_LIBPNG_VER >= 10504
+       png_set_scale_16(png_ptr);
+#else
+       png_set_strip_16(png_ptr);
+#endif
+
+(The more accurate "png_set_scale_16()" API became available in libpng version
+1.5.4).
+
+If you need to process the alpha channel on the image separately from the image
+data (for example if you convert it to a bitmap mask) it is possible to have
+libpng strip the channel leaving just RGB or gray data:
+
+    if (color_type & PNG_COLOR_MASK_ALPHA)
+       png_set_strip_alpha(png_ptr);
+
+If you strip the alpha channel you need to find some other way of dealing with
+the information.  If, instead, you want to convert the image to an opaque
+version with no alpha channel use png_set_background; see below.
+
+As of libpng version 1.5.2, almost all useful expansions are supported, the
+major ommissions are conversion of grayscale to indexed images (which can be
+done trivially in the application) and conversion of indexed to grayscale (which
+can be done by a trivial manipulation of the palette.)
+
+In the following table, the 01 means grayscale with depth<8, 31 means
+indexed with depth<8, other numerals represent the color type, "T" means
+the tRNS chunk is present, A means an alpha channel is present, and O
+means tRNS or alpha is present but all pixels in the image are opaque.
+
+  FROM  01  31   0  0T  0O   2  2T  2O   3  3T  3O  4A  4O  6A  6O
+   TO
+   01    -  [G]  -   -   -   -   -   -   -   -   -   -   -   -   -
+   31   [Q]  Q  [Q] [Q] [Q]  Q   Q   Q   Q   Q   Q  [Q] [Q]  Q   Q
+    0    1   G   +   .   .   G   G   G   G   G   G   B   B  GB  GB
+   0T    lt  Gt  t   +   .   Gt  G   G   Gt  G   G   Bt  Bt GBt GBt
+   0O    lt  Gt  t   .   +   Gt  Gt  G   Gt  Gt  G   Bt  Bt GBt GBt
+    2    C   P   C   C   C   +   .   .   C   -   -  CB  CB   B   B
+   2T    Ct  -   Ct  C   C   t   +   t   -   -   -  CBt CBt  Bt  Bt
+   2O    Ct  -   Ct  C   C   t   t   +   -   -   -  CBt CBt  Bt  Bt
+    3   [Q]  p  [Q] [Q] [Q]  Q   Q   Q   +   .   .  [Q] [Q]  Q   Q
+   3T   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   +   t  [Qt][Qt] Qt  Qt
+   3O   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   t   +  [Qt][Qt] Qt  Qt
+   4A    lA  G   A   T   T   GA  GT  GT  GA  GT  GT  +   BA  G  GBA
+   4O    lA GBA  A   T   T   GA  GT  GT  GA  GT  GT  BA  +  GBA  G
+   6A    CA  PA  CA  C   C   A   T  tT   PA  P   P   C  CBA  +   BA
+   6O    CA PBA  CA  C   C   A  tT   T   PA  P   P  CBA  C   BA  +
+
+Within the matrix,
+     "+" identifies entries where 'from' and 'to' are the same.
+     "-" means the transformation is not supported.
+     "." means nothing is necessary (a tRNS chunk can just be ignored).
+     "t" means the transformation is obtained by png_set_tRNS.
+     "A" means the transformation is obtained by png_set_add_alpha().
+     "X" means the transformation is obtained by png_set_expand().
+     "1" means the transformation is obtained by
+         png_set_expand_gray_1_2_4_to_8() (and by png_set_expand()
+         if there is no transparency in the original or the final
+         format).
+     "C" means the transformation is obtained by png_set_gray_to_rgb().
+     "G" means the transformation is obtained by png_set_rgb_to_gray().
+     "P" means the transformation is obtained by
+         png_set_expand_palette_to_rgb().
+     "p" means the transformation is obtained by png_set_packing().
+     "Q" means the transformation is obtained by png_set_quantize().
+     "T" means the transformation is obtained by
+         png_set_tRNS_to_alpha().
+     "B" means the transformation is obtained by
+         png_set_background(), or png_strip_alpha().
+
+When an entry has multiple transforms listed all are required to cause the
+right overall transformation.  When two transforms are separated by a comma
+either will do the job.  When transforms are enclosed in [] the transform should
+do the job but this is currently unimplemented - a different format will result
+if the suggested transformations are used.
+
+In PNG files, the alpha channel in an image
+is the level of opacity.  If you need the alpha channel in an image to
+be the level of transparency instead of opacity, you can invert the
+alpha channel (or the tRNS chunk data) after it's read, so that 0 is
+fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
+images) is fully transparent, with
+
+    png_set_invert_alpha(png_ptr);
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit
+files.  This code expands to 1 pixel per byte without changing the
+values of the pixels:
+
+    if (bit_depth < 8)
+       png_set_packing(png_ptr);
+
+PNG files have possible bit depths of 1, 2, 4, 8, and 16.  All pixels
+stored in a PNG image have been "scaled" or "shifted" up to the next
+higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
+to 8 bits/sample in the range [0, 255]).  However, it is also possible
+to convert the PNG pixel data back to the original bit depth of the
+image.  This call reduces the pixels back down to the original bit depth:
+
+    png_color_8p sig_bit;
+
+    if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
+       png_set_shift(png_ptr, sig_bit);
+
+PNG files store 3-color pixels in red, green, blue order.  This code
+changes the storage of the pixels to blue, green, red:
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_bgr(png_ptr);
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
+into 4 or 8 bytes for windowing systems that need them in this format:
+
+    if (color_type == PNG_COLOR_TYPE_RGB)
+       png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
+
+where "filler" is the 8-bit or 16-bit number to fill with, and the location
+is either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
+you want the filler before the RGB or after. When filling an 8-bit pixel,
+the least significant 8 bits of the number are used, if a 16-bit number is
+supplied.  This transformation does not affect images that already have full
+alpha channels.  To add an opaque alpha channel, use filler=0xffff and
+PNG_FILLER_AFTER which will generate RGBA pixels.
+
+Note that png_set_filler() does not change the color type.  If you want
+to do that, you can add a true alpha channel with
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+       color_type == PNG_COLOR_TYPE_GRAY)
+       png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
+
+where "filler" contains the alpha value to assign to each pixel.
+The png_set_add_alpha() function was added in libpng-1.2.7.
+
+If you are reading an image with an alpha channel, and you need the
+data as ARGB instead of the normal PNG format RGBA:
+
+    if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_swap_alpha(png_ptr);
+
+For some uses, you may want a grayscale image to be represented as
+RGB.  This code will do that conversion:
+
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+       png_set_gray_to_rgb(png_ptr);
+
+Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
+with alpha.
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_rgb_to_gray(png_ptr, error_action,
+          double red_weight, double green_weight);
+
+    error_action = 1: silently do the conversion
+
+    error_action = 2: issue a warning if the original
+                      image has any pixel where
+                      red != green or red != blue
+
+    error_action = 3: issue an error and abort the
+                      conversion if the original
+                      image has any pixel where
+                      red != green or red != blue
+
+    red_weight:       weight of red component
+
+    green_weight:     weight of green component
+                      If either weight is negative, default
+                      weights are used.
+
+In the corresponding fixed point API the red_weight and green_weight values are
+simply scaled by 100,000:
+
+    png_set_rgb_to_gray(png_ptr, error_action,
+       png_fixed_point red_weight,
+       png_fixed_point green_weight);
+
+If you have set error_action = 1 or 2, you can
+later check whether the image really was gray, after processing
+the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
+It will return a png_byte that is zero if the image was gray or
+1 if there were any non-gray pixels.  Background and sBIT data
+will be silently converted to grayscale, using the green channel
+data for sBIT, regardless of the error_action setting.
+
+The default values come from the PNG file cHRM chunk if present; otherwise, the
+defaults correspond to the ITU-R recommendation 709, and also the sRGB color
+space, as recommended in the Charles Poynton's Colour FAQ,
+Copyright (c) 2006-11-28 Charles Poynton, in section 9:
+
+<http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
+
+    Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
+
+Previous versions of this document, 1998 through 2002, recommended a slightly
+different formula:
+
+    Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+
+Libpng uses an integer approximation:
+
+    Y = (6968 * R + 23434 * G + 2366 * B)/32768
+
+The calculation is done in a linear colorspace, if the image gamma
+can be determined.
+
+The png_set_background() function has been described already; it tells libpng to
+composite images with alpha or simple transparency against the supplied
+background color.  For compatibility with versions of libpng earlier than
+libpng-1.5.4 it is recommended that you call the function after reading the file
+header, even if you don't want to use the color in a bKGD chunk, if one exists.
+
+If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
+you may use this color, or supply another color more suitable for
+the current display (e.g., the background color from a web page).  You
+need to tell libpng how the color is represented, both the format of the
+component values in the color (the number of bits) and the gamma encoding of the
+color.  The function takes two arguments, background_gamma_mode and need_expand
+to convey this information; however, only two combinations are likely to be
+useful:
+
+    png_color_16 my_background;
+    png_color_16p image_background;
+
+    if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+       png_set_background(png_ptr, image_background,
+           PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
+    else
+       png_set_background(png_ptr, &my_background,
+           PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
+
+The second call was described above - my_background is in the format of the
+final, display, output produced by libpng.  Because you now know the format of
+the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
+output and to retain palette images (the palette colors will be modified
+appropriately and the tRNS chunk removed.)  However, if you are doing this,
+take great care not to ask for transformations without checking first that
+they apply!
+
+In the first call the background color has the original bit depth and color type
+of the PNG file.  So, for palette images the color is supplied as a palette
+index and for low bit greyscale images the color is a reduced bit value in
+image_background->gray.
+
+If you didn't call png_set_gamma() before reading the file header, for example
+if you need your code to remain compatible with older versions of libpng prior
+to libpng-1.5.4, this is the place to call it.
+
+Do not call it if you called png_set_alpha_mode(); doing so will damage the
+settings put in place by png_set_alpha_mode().  (If png_set_alpha_mode() is
+supported then you can certainly do png_set_gamma() before reading the PNG
+header.)
+
+This API unconditionally sets the screen and file gamma values, so it will
+override the value in the PNG file unless it is called before the PNG file
+reading starts.  For this reason you must always call it with the PNG file
+value when you call it in this position:
+
+   if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
+      png_set_gamma(png_ptr, screen_gamma, file_gamma);
+
+   else
+      png_set_gamma(png_ptr, screen_gamma, 0.45455);
+
+If you need to reduce an RGB file to a paletted file, or if a paletted
+file has more entries than will fit on your screen, png_set_quantize()
+will do that.  Note that this is a simple match quantization that merely
+finds the closest color available.  This should work fairly well with
+optimized palettes, but fairly badly with linear color cubes.  If you
+pass a palette that is larger than maximum_colors, the file will
+reduce the number of colors in the palette so it will fit into
+maximum_colors.  If there is a histogram, libpng will use it to make
+more intelligent choices when reducing the palette.  If there is no
+histogram, it may not do as good a job.
+
+   if (color_type & PNG_COLOR_MASK_COLOR)
+   {
+      if (png_get_valid(png_ptr, info_ptr,
+          PNG_INFO_PLTE))
+      {
+         png_uint_16p histogram = NULL;
+
+         png_get_hIST(png_ptr, info_ptr,
+             &histogram);
+         png_set_quantize(png_ptr, palette, num_palette,
+            max_screen_colors, histogram, 1);
+      }
+
+      else
+      {
+         png_color std_color_cube[MAX_SCREEN_COLORS] =
+            { ... colors ... };
+
+         png_set_quantize(png_ptr, std_color_cube,
+            MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
+            NULL,0);
+      }
+   }
+
+PNG files describe monochrome as black being zero and white being one.
+The following code will reverse this (make black be one and white be
+zero):
+
+   if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
+      png_set_invert_mono(png_ptr);
+
+This function can also be used to invert grayscale and gray-alpha images:
+
+   if (color_type == PNG_COLOR_TYPE_GRAY ||
+       color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      png_set_invert_mono(png_ptr);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first).  This code changes the storage to the
+other way (little-endian, i.e. least significant bits first, the
+way PCs store them):
+
+    if (bit_depth == 16)
+       png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+    if (bit_depth < 8)
+       png_set_packswap(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs.  This is done by setting a callback
+with
+
+    png_set_read_user_transform_fn(png_ptr,
+        read_transform_fn);
+
+You must supply the function
+
+    void read_transform_fn(png_structp png_ptr, png_row_infop
+        row_info, png_bytep data)
+
+See pngtest.c for a working example.  Your function will be called
+after all of the other transformations have been processed.  Take care with
+interlaced images if you do the interlace yourself - the width of the row is the
+width in 'row_info', not the overall image width.
+
+If supported, libpng provides two information routines that you can use to find
+where you are in processing the image:
+
+   png_get_current_pass_number(png_structp png_ptr);
+   png_get_current_row_number(png_structp png_ptr);
+
+Don't try using these outside a transform callback - firstly they are only
+supported if user transforms are supported, secondly they may well return
+unexpected results unless the row is actually being processed at the moment they
+are called.
+
+With interlaced
+images the value returned is the row in the input sub-image image.  Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function, and you can inform libpng that your transform
+function will change the number of channels or bit depth with the
+function
+
+    png_set_user_transform_info(png_ptr, user_ptr,
+        user_depth, user_channels);
+
+The user's application, not libpng, is responsible for allocating and
+freeing any memory required for the user structure.
+
+You can retrieve the pointer via the function
+png_get_user_transform_ptr().  For example:
+
+    voidp read_user_transform_ptr =
+        png_get_user_transform_ptr(png_ptr);
+
+The last thing to handle is interlacing; this is covered in detail below,
+but you must call the function here if you want libpng to handle expansion
+of the interlaced image.
+
+    number_of_passes = png_set_interlace_handling(png_ptr);
+
+After setting the transformations, libpng can update your png_info
+structure to reflect any transformations you've requested with this
+call.
+
+    png_read_update_info(png_ptr, info_ptr);
+
+This is most useful to update the info structure's rowbytes
+field so you can use it to allocate your image memory.  This function
+will also update your palette with the correct screen_gamma and
+background if these have been given with the calls above.  You may
+only call png_read_update_info() once with a particular info_ptr.
+
+After you call png_read_update_info(), you can allocate any
+memory you need to hold the image.  The row data is simply
+raw byte data for all forms of images.  As the actual allocation
+varies among applications, no example will be given.  If you
+are allocating one large chunk, you will need to build an
+array of pointers to each row, as it will be needed for some
+of the functions below.
+
+Be sure that your platform can allocate the buffer that you'll need.
+libpng internally checks for oversize width, but you'll need to
+do your own check for number_of_rows*width*pixel_size if you are using
+a multiple-row buffer:
+
+   /* Guard against integer overflow */
+   if (number_of_rows > PNG_SIZE_MAX/(width*pixel_size)) {
+        png_error(png_ptr,"image_data buffer would be too large");
+   }
+
+Remember: Before you call png_read_update_info(), the png_get_*()
+functions return the values corresponding to the original PNG image.
+After you call png_read_update_info the values refer to the image
+that libpng will output.  Consequently you must call all the png_set_
+functions before you call png_read_update_info().  This is particularly
+important for png_set_interlace_handling() - if you are going to call
+png_read_update_info() you must call png_set_interlace_handling() before
+it unless you want to receive interlaced output.
+
+.SS Reading image data
+
+After you've allocated memory, you can read the image data.
+The simplest way to do this is in one function call.  If you are
+allocating enough memory to hold the whole image, you can just
+call png_read_image() and libpng will read in all the image data
+and put it in the memory area supplied.  You will need to pass in
+an array of pointers to each row.
+
+This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() (unless you call
+png_read_update_info()) or call this function multiple times, or any
+of that other stuff necessary with png_read_rows().
+
+   png_read_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+   png_bytep row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to read in the whole image at once, you can
+use png_read_rows() instead.  If there is no interlacing (check
+interlace_type == PNG_INTERLACE_NONE), this is simple:
+
+    png_read_rows(png_ptr, row_pointers, NULL,
+        number_of_rows);
+
+where row_pointers is the same as in the png_read_image() call.
+
+If you are doing this just one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+    png_bytep row_pointer = row;
+    png_read_row(png_ptr, row_pointer, NULL);
+
+If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
+get somewhat harder.  The only current (PNG Specification version 1.2)
+interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
+a somewhat complicated 2D interlace scheme, known as Adam7, that
+breaks down an image into seven smaller images of varying size, based
+on an 8x8 grid.  This number is defined (from libpng 1.5) as
+PNG_INTERLACE_ADAM7_PASSES in png.h
+
+libpng can fill out those images or it can give them to you "as is".
+It is almost always better to have libpng handle the interlacing for you.
+If you want the images filled out, there are two ways to do that.  The one
+mentioned in the PNG specification is to expand each pixel to cover
+those pixels that have not been read yet (the "rectangle" method).
+This results in a blocky image for the first pass, which gradually
+smooths out as more pixels are read.  The other method is the "sparkle"
+method, where pixels are drawn only in their final locations, with the
+rest of the image remaining whatever colors they were initialized to
+before the start of the read.  The first method usually looks better,
+but tends to be slower, as there are more pixels to put in the rows.
+
+If, as is likely, you want libpng to expand the images, call this before
+calling png_start_read_image() or png_read_update_info():
+
+    if (interlace_type == PNG_INTERLACE_ADAM7)
+       number_of_passes
+           = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed.  Currently, this is seven,
+but may change if another interlace type is added.  This function can be
+called even if the file is not interlaced, where it will return one pass.
+You then need to read the whole image 'number_of_passes' times.  Each time
+will distribute the pixels from the current pass to the correct place in
+the output image, so you need to supply the same rows to png_read_rows in
+each pass.
+
+If you are not going to display the image after each pass, but are
+going to wait until the entire image is read in, use the sparkle
+effect.  This effect is faster and the end result of either method
+is exactly the same.  If you are planning on displaying the image
+after each pass, the "rectangle" effect is generally considered the
+better looking one.
+
+If you only want the "sparkle" effect, just call png_read_row() or
+png_read_rows() as
+normal, with the third parameter NULL.  Make sure you make pass over
+the image number_of_passes times, and you don't change the data in the
+rows between calls.  You can change the locations of the data, just
+not the data.  Each pass only writes the pixels appropriate for that
+pass, and assumes the data from previous passes is still valid.
+
+    png_read_rows(png_ptr, row_pointers, NULL,
+        number_of_rows);
+    or
+    png_read_row(png_ptr, row_pointers, NULL);
+
+If you only want the first effect (the rectangles), do the same as
+before except pass the row buffer in the third parameter, and leave
+the second parameter NULL.
+
+    png_read_rows(png_ptr, NULL, row_pointers,
+        number_of_rows);
+    or
+    png_read_row(png_ptr, NULL, row_pointers);
+
+If you don't want libpng to handle the interlacing details, just call
+png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
+Each of the images is a valid image by itself; however, you will almost
+certainly need to distribute the pixels from each sub-image to the
+correct place.  This is where everything gets very tricky.
+
+If you want to retrieve the separate images you must pass the correct
+number of rows to each successive call of png_read_rows().  The calculation
+gets pretty complicated for small images, where some sub-images may
+not even exist because either their width or height ends up zero.
+libpng provides two macros to help you in 1.5 and later versions:
+
+   png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
+   png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
+
+Respectively these tell you the width and height of the sub-image
+corresponding to the numbered pass.  'pass' is in in the range 0 to 6 -
+this can be confusing because the specification refers to the same passes
+as 1 to 7!  Be careful, you must check both the width and height before
+calling png_read_rows() and not call it for that pass if either is zero.
+
+You can, of course, read each sub-image row by row.  If you want to
+produce optimal code to make a pixel-by-pixel transformation of an
+interlaced image this is the best approach; read each row of each pass,
+transform it, and write it out to a new interlaced image.
+
+If you want to de-interlace the image yourself libpng provides further
+macros to help that tell you where to place the pixels in the output image.
+Because the interlacing scheme is rectangular - sub-image pixels are always
+arranged on a rectangular grid - all you need to know for each pass is the
+starting column and row in the output image of the first pixel plus the
+spacing between each pixel.  As of libpng 1.5 there are four macros to
+retrieve this information:
+
+   png_uint_32 x = PNG_PASS_START_COL(pass);
+   png_uint_32 y = PNG_PASS_START_ROW(pass);
+   png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
+   png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
+
+These allow you to write the obvious loop:
+
+   png_uint_32 input_y = 0;
+   png_uint_32 output_y = PNG_PASS_START_ROW(pass);
+
+   while (output_y < output_image_height)
+   {
+      png_uint_32 input_x = 0;
+      png_uint_32 output_x = PNG_PASS_START_COL(pass);
+
+      while (output_x < output_image_width)
+      {
+         image[output_y][output_x] =
+             subimage[pass][input_y][input_x++];
+
+         output_x += xStep;
+      }
+
+      ++input_y;
+      output_y += yStep;
+   }
+
+Notice that the steps between successive output rows and columns are
+returned as shifts.  This is possible because the pixels in the subimages
+are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
+image.  In practice you may need to directly calculate the output coordinate
+given an input coordinate.  libpng provides two further macros for this
+purpose:
+
+   png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
+   png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
+
+Finally a pair of macros are provided to tell you if a particular image
+row or column appears in a given pass:
+
+   int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
+   int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
+
+Bear in mind that you will probably also need to check the width and height
+of the pass in addition to the above to be sure the pass even exists!
+
+With any luck you are convinced by now that you don't want to do your own
+interlace handling.  In reality normally the only good reason for doing this
+is if you are processing PNG files on a pixel-by-pixel basis and don't want
+to load the whole file into memory when it is interlaced.
+
+libpng includes a test program, pngvalid, that illustrates reading and
+writing of interlaced images.  If you can't get interlacing to work in your
+code and don't want to leave it to libpng (the recommended approach), see
+how pngvalid.c does it.
+
+.SS Finishing a sequential read
+
+After you are finished reading the image through the
+low-level interface, you can finish reading the file.
+
+If you want to use a different crc action for handling CRC errors in
+chunks after the image data, you can call png_set_crc_action()
+again at this point.
+
+If you are interested in comments or time, which may be stored either
+before or after the image data, you should pass the separate png_info
+struct if you want to keep the comments from before and after the image
+separate.
+
+    png_infop end_info = png_create_info_struct(png_ptr);
+
+    if (!end_info)
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+           (png_infopp)NULL);
+       return ERROR;
+    }
+
+   png_read_end(png_ptr, end_info);
+
+If you are not interested, you should still call png_read_end()
+but you can pass NULL, avoiding the need to create an end_info structure.
+If you do this, libpng will not process any chunks after IDAT other than
+skipping over them and perhaps (depending on whether you have called
+png_set_crc_action) checking their CRCs while looking for the IEND chunk.
+
+   png_read_end(png_ptr, (png_infop)NULL);
+
+If you don't call png_read_end(), then your file pointer will be
+left pointing to the first chunk after the last IDAT, which is probably
+not what you want if you expect to read something beyond the end of
+the PNG datastream.
+
+When you are done, you can free all memory allocated by libpng like this:
+
+   png_destroy_read_struct(&png_ptr, &info_ptr,
+       &end_info);
+
+or, if you didn't create an end_info structure,
+
+   png_destroy_read_struct(&png_ptr, &info_ptr,
+       (png_infopp)NULL);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+    png_free_data(png_ptr, info_ptr, mask, seq)
+
+    mask - identifies data to be freed, a mask
+           containing the bitwise OR of one or
+           more of
+             PNG_FREE_PLTE, PNG_FREE_TRNS,
+             PNG_FREE_HIST, PNG_FREE_ICCP,
+             PNG_FREE_PCAL, PNG_FREE_ROWS,
+             PNG_FREE_SCAL, PNG_FREE_SPLT,
+             PNG_FREE_TEXT, PNG_FREE_UNKN,
+           or simply PNG_FREE_ALL
+
+    seq  - sequence number of item to be freed
+           (\-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng,  and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed.  If "seq" is not \-1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+The default behavior is only to free data that was allocated internally
+by libpng.  This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+    png_data_freer(png_ptr, info_ptr, freer, mask)
+
+    freer  - one of
+               PNG_DESTROY_WILL_FREE_DATA
+               PNG_SET_WILL_FREE_DATA
+               PNG_USER_WILL_FREE_DATA
+
+    mask   - which data elements are affected
+             same choices as in png_free_data()
+
+This function only affects data that has already been allocated.
+You can call this function after reading the PNG data but before calling
+any png_set_*() functions, to control whether the user or the png_set_*()
+function is responsible for freeing any existing data that might be present,
+and again after the png_set_*() functions to control whether the user
+or png_destroy_*() is supposed to free the data.  When the user assumes
+responsibility for libpng-allocated data, the application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated your row_pointers in a single block, as suggested above in
+the description of the high level read interface, you must not transfer
+responsibility for freeing it to the png_set_rows or png_read_destroy function,
+because they would also try to free the individual row_pointers[i].
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key.  Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+
+The png_free_data() function will turn off the "valid" flag for anything
+it frees.  If you need to turn the flag off for a chunk that was freed by
+your application instead of by libpng, you can use
+
+    png_set_invalid(png_ptr, info_ptr, mask);
+
+    mask - identifies the chunks to be made invalid,
+           containing the bitwise OR of one or
+           more of
+             PNG_INFO_gAMA, PNG_INFO_sBIT,
+             PNG_INFO_cHRM, PNG_INFO_PLTE,
+             PNG_INFO_tRNS, PNG_INFO_bKGD,
+             PNG_INFO_eXIf,
+             PNG_INFO_hIST, PNG_INFO_pHYs,
+             PNG_INFO_oFFs, PNG_INFO_tIME,
+             PNG_INFO_pCAL, PNG_INFO_sRGB,
+             PNG_INFO_iCCP, PNG_INFO_sPLT,
+             PNG_INFO_sCAL, PNG_INFO_IDAT
+
+For a more compact example of reading a PNG image, see the file example.c.
+
+.SS Reading PNG files progressively
+
+The progressive reader is slightly different from the non-progressive
+reader.  Instead of calling png_read_info(), png_read_rows(), and
+png_read_end(), you make one call to png_process_data(), which calls
+callbacks when it has the info, a row, or the end of the image.  You
+set up these callbacks with png_set_progressive_read_fn().  You don't
+have to worry about the input/output functions of libpng, as you are
+giving the library the data directly in png_process_data().  I will
+assume that you have read the section on reading PNG files above,
+so I will only highlight the differences (although I will show
+all of the code).
+
+png_structp png_ptr;
+png_infop info_ptr;
+
+ /*  An example code fragment of how you would
+     initialize the progressive reader in your
+     application. */
+ int
+ initialize_png_reader()
+ {
+    png_ptr = png_create_read_struct
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+         user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+        return ERROR;
+
+    info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+    {
+       png_destroy_read_struct(&png_ptr,
+          (png_infopp)NULL, (png_infopp)NULL);
+       return ERROR;
+    }
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+          (png_infopp)NULL);
+       return ERROR;
+    }
+
+    /* This one's new.  You can provide functions
+       to be called when the header info is valid,
+       when each row is completed, and when the image
+       is finished.  If you aren't using all functions,
+       you can specify NULL parameters.  Even when all
+       three functions are NULL, you need to call
+       png_set_progressive_read_fn().  You can use
+       any struct as the user_ptr (cast to a void pointer
+       for the function call), and retrieve the pointer
+       from inside the callbacks using the function
+
+          png_get_progressive_ptr(png_ptr);
+
+       which will return a void pointer, which you have
+       to cast appropriately.
+     */
+    png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
+        info_callback, row_callback, end_callback);
+
+    return 0;
+ }
+
+ /* A code fragment that you call as you receive blocks
+   of data */
+ int
+ process_data(png_bytep buffer, png_uint_32 length)
+ {
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+           (png_infopp)NULL);
+       return ERROR;
+    }
+
+    /* This one's new also.  Simply give it a chunk
+       of data from the file stream (in order, of
+       course).  On machines with segmented memory
+       models machines, don't give it any more than
+       64K.  The library seems to run fine with sizes
+       of 4K. Although you can give it much less if
+       necessary (I assume you can give it chunks of
+       1 byte, I haven't tried less than 256 bytes
+       yet).  When this function returns, you may
+       want to display any rows that were generated
+       in the row callback if you don't already do
+       so there.
+     */
+    png_process_data(png_ptr, info_ptr, buffer, length);
+
+    /* At this point you can call png_process_data_skip if
+       you want to handle data the library will skip yourself;
+       it simply returns the number of bytes to skip (and stops
+       libpng skipping that number of bytes on the next
+       png_process_data call).
+    return 0;
+ }
+
+ /* This function is called (as set by
+    png_set_progressive_read_fn() above) when enough data
+    has been supplied so all of the header has been
+    read.
+ */
+ void
+ info_callback(png_structp png_ptr, png_infop info)
+ {
+    /* Do any setup here, including setting any of
+       the transformations mentioned in the Reading
+       PNG files section.  For now, you _must_ call
+       either png_start_read_image() or
+       png_read_update_info() after all the
+       transformations are set (even if you don't set
+       any).  You may start getting rows before
+       png_process_data() returns, so this is your
+       last chance to prepare for that.
+
+       This is where you turn on interlace handling,
+       assuming you don't want to do it yourself.
+
+       If you need to you can stop the processing of
+       your original input data at this point by calling
+       png_process_data_pause.  This returns the number
+       of unprocessed bytes from the last png_process_data
+       call - it is up to you to ensure that the next call
+       sees these bytes again.  If you don't want to bother
+       with this you can get libpng to cache the unread
+       bytes by setting the 'save' parameter (see png.h) but
+       then libpng will have to copy the data internally.
+     */
+ }
+
+ /* This function is called when each row of image
+    data is complete */
+ void
+ row_callback(png_structp png_ptr, png_bytep new_row,
+    png_uint_32 row_num, int pass)
+ {
+    /* If the image is interlaced, and you turned
+       on the interlace handler, this function will
+       be called for every row in every pass.  Some
+       of these rows will not be changed from the
+       previous pass.  When the row is not changed,
+       the new_row variable will be NULL.  The rows
+       and passes are called in order, so you don't
+       really need the row_num and pass, but I'm
+       supplying them because it may make your life
+       easier.
+
+       If you did not turn on interlace handling then
+       the callback is called for each row of each
+       sub-image when the image is interlaced.  In this
+       case 'row_num' is the row in the sub-image, not
+       the row in the output image as it is in all other
+       cases.
+
+       For the non-NULL rows of interlaced images when
+       you have switched on libpng interlace handling,
+       you must call png_progressive_combine_row()
+       passing in the row and the old row.  You can
+       call this function for NULL rows (it will just
+       return) and for non-interlaced images (it just
+       does the memcpy for you) if it will make the
+       code easier.  Thus, you can just do this for
+       all cases if you switch on interlace handling;
+     */
+
+        png_progressive_combine_row(png_ptr, old_row,
+          new_row);
+
+    /* where old_row is what was displayed
+       previously for the row.  Note that the first
+       pass (pass == 0, really) will completely cover
+       the old row, so the rows do not have to be
+       initialized.  After the first pass (and only
+       for interlaced images), you will have to pass
+       the current row, and the function will combine
+       the old row and the new row.
+
+       You can also call png_process_data_pause in this
+       callback - see above.
+    */
+ }
+
+ void
+ end_callback(png_structp png_ptr, png_infop info)
+ {
+    /* This function is called after the whole image
+       has been read, including any chunks after the
+       image (up to and including the IEND).  You
+       will usually have the same info chunk as you
+       had in the header, although some data may have
+       been added to the comments and time fields.
+
+       Most people won't do much here, perhaps setting
+       a flag that marks the image as finished.
+     */
+ }
+
+
+
+.SH IV. Writing
+
+Much of this is very similar to reading.  However, everything of
+importance is repeated here, so you won't have to constantly look
+back up in the reading section to understand writing.
+
+.SS Setup
+
+You will want to do the I/O initialization before you get into libpng,
+so if it doesn't work, you don't have anything to undo. If you are not
+using the standard I/O functions, you will need to replace them with
+custom writing functions.  See the discussion under Customizing libpng.
+
+    FILE *fp = fopen(file_name, "wb");
+
+    if (!fp)
+       return ERROR;
+
+Next, png_struct and png_info need to be allocated and initialized.
+As these can be both relatively large, you may not want to store these
+on the stack, unless you have stack space to spare.  Of course, you
+will want to check if they return NULL.  If you are also reading,
+you won't want to name your read structure and your write structure
+both "png_ptr"; you can call them anything you like, such as
+"read_ptr" and "write_ptr".  Look at pngtest.c, for example.
+
+    png_structp png_ptr = png_create_write_struct
+       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+       return ERROR;
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr)
+    {
+       png_destroy_write_struct(&png_ptr,
+           (png_infopp)NULL);
+       return ERROR;
+    }
+
+If you want to use your own memory allocation routines,
+define PNG_USER_MEM_SUPPORTED and use
+png_create_write_struct_2() instead of png_create_write_struct():
+
+    png_structp png_ptr = png_create_write_struct_2
+       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn, (png_voidp)
+        user_mem_ptr, user_malloc_fn, user_free_fn);
+
+After you have these structures, you will need to set up the
+error handling.  When libpng encounters an error, it expects to
+longjmp() back to your routine.  Therefore, you will need to call
+setjmp() and pass the png_jmpbuf(png_ptr).  If you
+write the file from different routines, you will need to update
+the png_jmpbuf(png_ptr) every time you enter a new routine that will
+call a png_*() function.  See your documentation of setjmp/longjmp
+for your compiler for more information on setjmp/longjmp.  See
+the discussion on libpng error handling in the Customizing Libpng
+section below for more information on the libpng error handling.
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+       fclose(fp);
+       return ERROR;
+    }
+    ...
+    return;
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+   png_set_check_for_invalid_index(png_ptr, 0);
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are written as-is by the encoder, resulting in an
+invalid PNG datastream as output.  In this case the application is
+responsible for ensuring that the pixel indexes are in range when it writes
+a PLTE chunk with fewer entries than the bit depth would allow.
+
+Now you need to set up the output code.  The default for libpng is to
+use the C function fwrite().  If you use this, you will need to pass a
+valid FILE * in the function png_init_io().  Be sure that the file is
+opened in binary mode.  Again, if you wish to handle writing data in
+another way, see the discussion on libpng I/O handling in the Customizing
+Libpng section below.
+
+    png_init_io(png_ptr, fp);
+
+If you are embedding your PNG into a datastream such as MNG, and don't
+want libpng to write the 8-byte signature, or if you have already
+written the signature in your application, use
+
+    png_set_sig_bytes(png_ptr, 8);
+
+to inform libpng that it should not write a signature.
+
+.SS Write callbacks
+
+At this point, you can set up a callback function that will be
+called after each row has been written, which you can use to control
+a progress meter or the like.  It's demonstrated in pngtest.c.
+You must supply a function
+
+    void write_row_callback(png_structp png_ptr, png_uint_32 row,
+       int pass);
+    {
+      /* put your code here */
+    }
+
+(You can give it another name that you like instead of "write_row_callback")
+
+To inform libpng about your function, use
+
+    png_set_write_status_fn(png_ptr, write_row_callback);
+
+When this function is called the row has already been completely processed and
+it has also been written out.  The 'row' and 'pass' refer to the next row to be
+handled.  For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0.  For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes.  Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass\-1', if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+You now have the option of modifying how the compression library will
+run.  The following functions are mainly for testing, but may be useful
+in some cases, like if you need to write PNG files extremely fast and
+are willing to give up some compression, or if you want to get the
+maximum possible compression at the expense of slower writing.  If you
+have no special needs in this area, let the library do what it wants by
+not calling this function at all, as it has been tuned to deliver a good
+speed/compression ratio. The second parameter to png_set_filter() is
+the filter method, for which the only valid values are 0 (as of the
+July 1999 PNG specification, version 1.2) or 64 (if you are writing
+a PNG datastream that is to be embedded in a MNG datastream).  The third
+parameter is a flag that indicates which filter type(s) are to be tested
+for each scanline.  See the PNG specification for details on the specific
+filter types.
+
+
+    /* turn on or off filtering, and/or choose
+       specific filters.  You can use either a single
+       PNG_FILTER_VALUE_NAME or the bitwise OR of one
+       or more PNG_FILTER_NAME masks.
+     */
+    png_set_filter(png_ptr, 0,
+       PNG_FILTER_NONE  | PNG_FILTER_VALUE_NONE |
+       PNG_FILTER_SUB   | PNG_FILTER_VALUE_SUB  |
+       PNG_FILTER_UP    | PNG_FILTER_VALUE_UP   |
+       PNG_FILTER_AVG   | PNG_FILTER_VALUE_AVG  |
+       PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
+       PNG_ALL_FILTERS  | PNG_FAST_FILTERS);
+
+If an application wants to start and stop using particular filters during
+compression, it should start out with all of the filters (to ensure that
+the previous row of pixels will be stored in case it's needed later),
+and then add and remove them after the start of compression.
+
+If you are writing a PNG datastream that is to be embedded in a MNG
+datastream, the second parameter can be either 0 or 64.
+
+The png_set_compression_*() functions interface to the zlib compression
+library, and should mostly be ignored unless you really know what you are
+doing.  The only generally useful call is png_set_compression_level()
+which changes how much time zlib spends on trying to compress the image
+data.  See the Compression Library (zlib.h and algorithm.txt, distributed
+with zlib) for details on the compression levels.
+
+    #include zlib.h
+
+    /* Set the zlib compression level */
+    png_set_compression_level(png_ptr,
+        Z_BEST_COMPRESSION);
+
+    /* Set other zlib parameters for compressing IDAT */
+    png_set_compression_mem_level(png_ptr, 8);
+    png_set_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_compression_window_bits(png_ptr, 15);
+    png_set_compression_method(png_ptr, 8);
+    png_set_compression_buffer_size(png_ptr, 8192)
+
+    /* Set zlib parameters for text compression
+     * If you don't call these, the parameters
+     * fall back on those defined for IDAT chunks
+     */
+    png_set_text_compression_mem_level(png_ptr, 8);
+    png_set_text_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_text_compression_window_bits(png_ptr, 15);
+    png_set_text_compression_method(png_ptr, 8);
+
+.SS Setting the contents of info for output
+
+You now need to fill in the png_info structure with all the data you
+wish to write before the actual image.  Note that the only thing you
+are allowed to write after the image is the text chunks and the time
+chunk (as of PNG Specification 1.2, anyway).  See png_write_end() and
+the latest PNG specification for more information on that.  If you
+wish to write them before the image, fill them in now, and flag that
+data as being valid.  If you want to wait until after the data, don't
+fill them until png_write_end().  For all the fields in png_info and
+their data types, see png.h.  For explanations of what the fields
+contain, see the PNG specification.
+
+Some of the more important parts of the png_info are:
+
+    png_set_IHDR(png_ptr, info_ptr, width, height,
+       bit_depth, color_type, interlace_type,
+       compression_type, filter_method)
+
+    width          - holds the width of the image
+                     in pixels (up to 2^31).
+
+    height         - holds the height of the image
+                     in pixels (up to 2^31).
+
+    bit_depth      - holds the bit depth of one of the
+                     image channels.
+                     (valid values are 1, 2, 4, 8, 16
+                     and depend also on the
+                     color_type.  See also significant
+                     bits (sBIT) below).
+
+    color_type     - describes which color/alpha
+                     channels are present.
+                     PNG_COLOR_TYPE_GRAY
+                        (bit depths 1, 2, 4, 8, 16)
+                     PNG_COLOR_TYPE_GRAY_ALPHA
+                        (bit depths 8, 16)
+                     PNG_COLOR_TYPE_PALETTE
+                        (bit depths 1, 2, 4, 8)
+                     PNG_COLOR_TYPE_RGB
+                        (bit_depths 8, 16)
+                     PNG_COLOR_TYPE_RGB_ALPHA
+                        (bit_depths 8, 16)
+
+                     PNG_COLOR_MASK_PALETTE
+                     PNG_COLOR_MASK_COLOR
+                     PNG_COLOR_MASK_ALPHA
+
+    interlace_type - PNG_INTERLACE_NONE or
+                     PNG_INTERLACE_ADAM7
+
+    compression_type - (must be
+                     PNG_COMPRESSION_TYPE_DEFAULT)
+
+    filter_method  - (must be PNG_FILTER_TYPE_DEFAULT
+                     or, if you are writing a PNG to
+                     be embedded in a MNG datastream,
+                     can also be
+                     PNG_INTRAPIXEL_DIFFERENCING)
+
+If you call png_set_IHDR(), the call must appear before any of the
+other png_set_*() functions, because they might require access to some of
+the IHDR settings.  The remaining png_set_*() functions can be called
+in any order.
+
+If you wish, you can reset the compression_type, interlace_type, or
+filter_method later by calling png_set_IHDR() again; if you do this, the
+width, height, bit_depth, and color_type must be the same in each call.
+
+    png_set_PLTE(png_ptr, info_ptr, palette,
+       num_palette);
+
+    palette        - the palette for the file
+                     (array of png_color)
+    num_palette    - number of entries in the palette
+
+
+    png_set_gAMA(png_ptr, info_ptr, file_gamma);
+    png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
+
+    file_gamma     - the gamma at which the image was
+                     created (PNG_INFO_gAMA)
+
+    int_file_gamma - 100,000 times the gamma at which
+                     the image was created
+
+    png_set_cHRM(png_ptr, info_ptr,  white_x, white_y, red_x, red_y,
+                     green_x, green_y, blue_x, blue_y)
+    png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X,
+                     green_Y, green_Z, blue_X, blue_Y, blue_Z)
+    png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y,
+                     int_red_x, int_red_y, int_green_x, int_green_y,
+                     int_blue_x, int_blue_y)
+    png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y,
+                     int_red_Z, int_green_X, int_green_Y, int_green_Z,
+                     int_blue_X, int_blue_Y, int_blue_Z)
+
+    {white,red,green,blue}_{x,y}
+                     A color space encoding specified using the chromaticities
+                     of the end points and the white point.
+
+    {red,green,blue}_{X,Y,Z}
+                     A color space encoding specified using the encoding end
+                     points - the CIE tristimulus specification of the intended
+                     color of the red, green and blue channels in the PNG RGB
+                     data.  The white point is simply the sum of the three end
+                     points.
+
+    png_set_sRGB(png_ptr, info_ptr, srgb_intent);
+
+    srgb_intent    - the rendering intent
+                     (PNG_INFO_sRGB) The presence of
+                     the sRGB chunk means that the pixel
+                     data is in the sRGB color space.
+                     This chunk also implies specific
+                     values of gAMA and cHRM.  Rendering
+                     intent is the CSS-1 property that
+                     has been defined by the International
+                     Color Consortium
+                     (http://www.color.org).
+                     It can be one of
+                     PNG_sRGB_INTENT_SATURATION,
+                     PNG_sRGB_INTENT_PERCEPTUAL,
+                     PNG_sRGB_INTENT_ABSOLUTE, or
+                     PNG_sRGB_INTENT_RELATIVE.
+
+
+    png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
+       srgb_intent);
+
+    srgb_intent    - the rendering intent
+                     (PNG_INFO_sRGB) The presence of the
+                     sRGB chunk means that the pixel
+                     data is in the sRGB color space.
+                     This function also causes gAMA and
+                     cHRM chunks with the specific values
+                     that are consistent with sRGB to be
+                     written.
+
+    png_set_iCCP(png_ptr, info_ptr, name, compression_type,
+                       profile, proflen);
+
+    name             - The profile name.
+
+    compression_type - The compression type; always
+                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+                       You may give NULL to this argument to
+                       ignore it.
+
+    profile          - International Color Consortium color
+                       profile data. May contain NULs.
+
+    proflen          - length of profile data in bytes.
+
+    png_set_sBIT(png_ptr, info_ptr, sig_bit);
+
+    sig_bit        - the number of significant bits for
+                     (PNG_INFO_sBIT) each of the gray, red,
+                     green, and blue channels, whichever are
+                     appropriate for the given color type
+                     (png_color_16)
+
+    png_set_tRNS(png_ptr, info_ptr, trans_alpha,
+       num_trans, trans_color);
+
+    trans_alpha    - array of alpha (transparency)
+                     entries for palette (PNG_INFO_tRNS)
+
+    num_trans      - number of transparent entries
+                     (PNG_INFO_tRNS)
+
+    trans_color    - graylevel or color sample values
+                     (in order red, green, blue) of the
+                     single transparent color for
+                     non-paletted images (PNG_INFO_tRNS)
+
+    png_set_eXIf_1(png_ptr, info_ptr, num_exif, exif);
+
+    exif           - Exif profile (array of
+                     png_byte) (PNG_INFO_eXIf)
+
+    png_set_hIST(png_ptr, info_ptr, hist);
+
+    hist           - histogram of palette (array of
+                     png_uint_16) (PNG_INFO_hIST)
+
+    png_set_tIME(png_ptr, info_ptr, mod_time);
+
+    mod_time       - time image was last modified
+                     (PNG_VALID_tIME)
+
+    png_set_bKGD(png_ptr, info_ptr, background);
+
+    background     - background color (of type
+                     png_color_16p) (PNG_VALID_bKGD)
+
+    png_set_text(png_ptr, info_ptr, text_ptr, num_text);
+
+    text_ptr       - array of png_text holding image
+                     comments
+
+    text_ptr[i].compression - type of compression used
+                 on "text" PNG_TEXT_COMPRESSION_NONE
+                           PNG_TEXT_COMPRESSION_zTXt
+                           PNG_ITXT_COMPRESSION_NONE
+                           PNG_ITXT_COMPRESSION_zTXt
+    text_ptr[i].key   - keyword for comment.  Must contain
+                 1-79 characters.
+    text_ptr[i].text  - text comments for current
+                         keyword.  Can be NULL or empty.
+    text_ptr[i].text_length - length of text string,
+                 after decompression, 0 for iTXt
+    text_ptr[i].itxt_length - length of itxt string,
+                 after decompression, 0 for tEXt/zTXt
+    text_ptr[i].lang  - language of comment (NULL or
+                         empty for unknown).
+    text_ptr[i].translated_keyword  - keyword in UTF-8 (NULL
+                         or empty for unknown).
+
+    Note that the itxt_length, lang, and lang_key
+    members of the text_ptr structure only exist when the
+    library is built with iTXt chunk support.  Prior to
+    libpng-1.4.0 the library was built by default without
+    iTXt support. Also note that when iTXt is supported,
+    they contain NULL pointers when the "compression"
+    field contains PNG_TEXT_COMPRESSION_NONE or
+    PNG_TEXT_COMPRESSION_zTXt.
+
+    num_text       - number of comments
+
+    png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
+       num_spalettes);
+
+    palette_ptr    - array of png_sPLT_struct structures
+                     to be added to the list of palettes
+                     in the info structure.
+    num_spalettes  - number of palette structures to be
+                     added.
+
+    png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
+        unit_type);
+
+    offset_x  - positive offset from the left
+                     edge of the screen
+
+    offset_y  - positive offset from the top
+                     edge of the screen
+
+    unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+    png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
+        unit_type);
+
+    res_x       - pixels/unit physical resolution
+                  in x direction
+
+    res_y       - pixels/unit physical resolution
+                  in y direction
+
+    unit_type   - PNG_RESOLUTION_UNKNOWN,
+                  PNG_RESOLUTION_METER
+
+    png_set_sCAL(png_ptr, info_ptr, unit, width, height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+
+    height      - height of a pixel in physical scale units
+                  (width and height are doubles)
+
+    png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+                  expressed as a string
+
+    height      - height of a pixel in physical scale units
+                 (width and height are strings like "2.54")
+
+    png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
+       num_unknowns)
+
+    unknowns          - array of png_unknown_chunk
+                        structures holding unknown chunks
+    unknowns[i].name  - name of unknown chunk
+    unknowns[i].data  - data of unknown chunk
+    unknowns[i].size  - size of unknown chunk's data
+    unknowns[i].location - position to write chunk in file
+                           0: do not write chunk
+                           PNG_HAVE_IHDR: before PLTE
+                           PNG_HAVE_PLTE: before IDAT
+                           PNG_AFTER_IDAT: after IDAT
+
+The "location" member is set automatically according to
+what part of the output file has already been written.
+You can change its value after calling png_set_unknown_chunks()
+as demonstrated in pngtest.c.  Within each of the "locations",
+the chunks are sequenced according to their position in the
+structure (that is, the value of "i", which is the order in which
+the chunk was either read from the input file or defined with
+png_set_unknown_chunks).
+
+A quick word about text and num_text.  text is an array of png_text
+structures.  num_text is the number of valid structures in the array.
+Each png_text structure holds a language code, a keyword, a text value,
+and a compression type.
+
+The compression types have the same valid numbers as the compression
+types of the image data.  Currently, the only valid number is zero.
+However, you can store text either compressed or uncompressed, unlike
+images, which always have to be compressed.  So if you don't want the
+text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
+Because tEXt and zTXt chunks don't have a language field, if you
+specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
+any language code or translated keyword will not be written out.
+
+Until text gets around a few hundred bytes, it is not worth compressing it.
+After the text has been written out to the file, the compression type
+is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
+so that it isn't written out again at the end (in case you are calling
+png_write_end() with the same struct).
+
+The keywords that are given in the PNG Specification are:
+
+    Title            Short (one line) title or
+                     caption for image
+
+    Author           Name of image's creator
+
+    Description      Description of image (possibly long)
+
+    Copyright        Copyright notice
+
+    Creation Time    Time of original image creation
+                     (usually RFC 1123 format, see below)
+
+    Software         Software used to create the image
+
+    Disclaimer       Legal disclaimer
+
+    Warning          Warning of nature of content
+
+    Source           Device used to create the image
+
+    Comment          Miscellaneous comment; conversion
+                     from other image format
+
+The keyword-text pairs work like this.  Keywords should be short
+simple descriptions of what the comment is about.  Some typical
+keywords are found in the PNG specification, as is some recommendations
+on keywords.  You can repeat keywords in a file.  You can even write
+some text before the image and some after.  For example, you may want
+to put a description of the image before the image, but leave the
+disclaimer until after, so viewers working over modem connections
+don't have to wait for the disclaimer to go over the modem before
+they start seeing the image.  Finally, keywords should be full
+words, not abbreviations.  Keywords and text are in the ISO 8859-1
+(Latin-1) character set (a superset of regular ASCII) and can not
+contain NUL characters, and should not contain control or other
+unprintable characters.  To make the comments widely readable, stick
+with basic ASCII, and avoid machine specific character set extensions
+like the IBM-PC character set.  The keyword must be present, but
+you can leave off the text string on non-compressed pairs.
+Compressed pairs must have a text string, as only the text string
+is compressed anyway, so the compression would be meaningless.
+
+PNG supports modification time via the png_time structure.  Two
+conversion routines are provided, png_convert_from_time_t() for
+time_t and png_convert_from_struct_tm() for struct tm.  The
+time_t routine uses gmtime().  You don't have to use either of
+these, but if you wish to fill in the png_time structure directly,
+you should provide the time in universal time (GMT) if possible
+instead of your local time.  Note that the year number is the full
+year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
+that months start with 1.
+
+If you want to store the time of the original image creation, you should
+use a plain tEXt chunk with the "Creation Time" keyword.  This is
+necessary because the "creation time" of a PNG image is somewhat vague,
+depending on whether you mean the PNG file, the time the image was
+created in a non-PNG format, a still photo from which the image was
+scanned, or possibly the subject matter itself.  In order to facilitate
+machine-readable dates, it is recommended that the "Creation Time"
+tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
+although this isn't a requirement.  Unlike the tIME chunk, the
+"Creation Time" tEXt chunk is not expected to be automatically changed
+by the software.  To facilitate the use of RFC 1123 dates, a function
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
+convert from PNG time to an RFC 1123 format string.  The caller must provide
+a writeable buffer of at least 29 bytes.
+
+.SS Writing unknown chunks
+
+You can use the png_set_unknown_chunks function to queue up private chunks
+for writing.  You give it a chunk name, location, raw data, and a size.  You
+also must use png_set_keep_unknown_chunks() to ensure that libpng will
+handle them.  That's all there is to it.  The chunks will be written by the
+next following png_write_info_before_PLTE, png_write_info, or png_write_end
+function, depending upon the specified location.  Any chunks previously
+read into the info structure's unknown-chunk list will also be written out
+in a sequence that satisfies the PNG specification's ordering rules.
+
+Here is an example of writing two private chunks, prVt and miNE:
+
+    #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+    /* Set unknown chunk data */
+    png_unknown_chunk unk_chunk[2];
+    strcpy((char *) unk_chunk[0].name, "prVt";
+    unk_chunk[0].data = (unsigned char *) "PRIVATE DATA";
+    unk_chunk[0].size = strlen(unk_chunk[0].data)+1;
+    unk_chunk[0].location = PNG_HAVE_IHDR;
+    strcpy((char *) unk_chunk[1].name, "miNE";
+    unk_chunk[1].data = (unsigned char *) "MY CHUNK DATA";
+    unk_chunk[1].size = strlen(unk_chunk[0].data)+1;
+    unk_chunk[1].location = PNG_AFTER_IDAT;
+    png_set_unknown_chunks(write_ptr, write_info_ptr,
+        unk_chunk, 2);
+    /* Needed because miNE is not safe-to-copy */
+    png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
+       (png_bytep) "miNE", 1);
+    # if PNG_LIBPNG_VER < 10600
+      /* Deal with unknown chunk location bug in 1.5.x and earlier */
+      png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
+      png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
+    # endif
+    # if PNG_LIBPNG_VER < 10500
+      /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
+       * one before IDAT and another after IDAT, so don't use it; only use
+       * PNG_HAVE_IHDR location.  This call resets the location previously
+       * set by assignment and png_set_unknown_chunk_location() for chunk 1.
+       */
+      png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
+    # endif
+    #endif
+
+.SS The high-level write interface
+
+At this point there are two ways to proceed; through the high-level
+write interface, or through a sequence of low-level write operations.
+You can use the high-level interface if your image data is present
+in the info structure.  All defined output
+transformations are permitted, enabled by the following masks.
+
+    PNG_TRANSFORM_IDENTITY      No transformation
+    PNG_TRANSFORM_PACKING       Pack 1, 2 and 4-bit samples
+    PNG_TRANSFORM_PACKSWAP      Change order of packed
+                                pixels to LSB first
+    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
+    PNG_TRANSFORM_SHIFT         Normalize pixels to the
+                                sBIT depth
+    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
+                                to BGRA
+    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
+                                to AG
+    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
+                                to transparency
+    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
+    PNG_TRANSFORM_STRIP_FILLER        Strip out filler
+                                      bytes (deprecated).
+    PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
+                                      filler bytes
+    PNG_TRANSFORM_STRIP_FILLER_AFTER  Strip out trailing
+                                      filler bytes
+
+If you have valid image data in the info structure (you can use
+png_set_rows() to put image data in the info structure), simply do this:
+
+    png_write_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some set of
+transformation flags.  This call is equivalent to png_write_info(),
+followed the set of transformations indicated by the transform mask,
+then png_write_image(), and finally png_write_end().
+
+(The final parameter of this call is not yet used.  Someday it might point
+to transformation parameters required by some future output transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_write_png().
+
+.SS The low-level write interface
+
+If you are going the low-level route instead, you are now ready to
+write all the file information up to the actual image data.  You do
+this with a call to png_write_info().
+
+    png_write_info(png_ptr, info_ptr);
+
+Note that there is one transformation you may need to do before
+png_write_info().  In PNG files, the alpha channel in an image is the
+level of opacity.  If your data is supplied as a level of transparency,
+you can invert the alpha channel before you write it, so that 0 is
+fully transparent and 255 (in 8-bit or paletted images) or 65535
+(in 16-bit images) is fully opaque, with
+
+    png_set_invert_alpha(png_ptr);
+
+This must appear before png_write_info() instead of later with the
+other transformations because in the case of paletted images the tRNS
+chunk data has to be inverted before the tRNS chunk is written.  If
+your image is not a paletted image, the tRNS data (which in such cases
+represents a single color to be rendered as transparent) won't need to
+be changed, and you can safely do this transformation after your
+png_write_info() call.
+
+If you need to write a private chunk that you want to appear before
+the PLTE chunk when PLTE is present, you can write the PNG info in
+two steps, and insert code to write your own chunk between them:
+
+    png_write_info_before_PLTE(png_ptr, info_ptr);
+    png_set_unknown_chunks(png_ptr, info_ptr, ...);
+    png_write_info(png_ptr, info_ptr);
+
+After you've written the file information, you can set up the library
+to handle any special transformations of the image data.  The various
+ways to transform the data will be described in the order that they
+should occur.  This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths.  Even though each transformation
+checks to see if it has data that it can do something with, you should
+make sure to only enable a transformation if it will be valid for the
+data.  For example, don't swap red and blue on grayscale data.
+
+PNG files store RGB pixels packed into 3 or 6 bytes.  This code tells
+the library to strip input data that has 4 or 8 bytes per pixel down
+to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
+bytes per pixel).
+
+    png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
+PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
+is stored XRGB or RGBX.
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit files.
+If the data is supplied at 1 pixel per byte, use this code, which will
+correctly pack the pixels into a single byte:
+
+    png_set_packing(png_ptr);
+
+PNG files reduce possible bit depths to 1, 2, 4, 8, and 16.  If your
+data is of another bit depth, you can write an sBIT chunk into the
+file so that decoders can recover the original data if desired.
+
+    /* Set the true bit depth of the image data */
+    if (color_type & PNG_COLOR_MASK_COLOR)
+    {
+       sig_bit.red = true_bit_depth;
+       sig_bit.green = true_bit_depth;
+       sig_bit.blue = true_bit_depth;
+    }
+
+    else
+    {
+       sig_bit.gray = true_bit_depth;
+    }
+
+    if (color_type & PNG_COLOR_MASK_ALPHA)
+    {
+       sig_bit.alpha = true_bit_depth;
+    }
+
+    png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+If the data is stored in the row buffer in a bit depth other than
+one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
+this will scale the values to appear to be the correct bit depth as
+is required by PNG.
+
+    png_set_shift(png_ptr, &sig_bit);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first).  This code would be used if they are
+supplied the other way (little-endian, i.e. least significant bits
+first, the way PCs store them):
+
+    if (bit_depth > 8)
+       png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+    if (bit_depth < 8)
+       png_set_packswap(png_ptr);
+
+PNG files store 3 color pixels in red, green, blue order.  This code
+would be used if they are supplied as blue, green, red:
+
+    png_set_bgr(png_ptr);
+
+PNG files describe monochrome as black being zero and white being
+one. This code would be used if the pixels are supplied with this reversed
+(black being one and white being zero):
+
+    png_set_invert_mono(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs.  This is done by setting a callback
+with
+
+    png_set_write_user_transform_fn(png_ptr,
+       write_transform_fn);
+
+You must supply the function
+
+    void write_transform_fn(png_structp png_ptr, png_row_infop
+       row_info, png_bytep data)
+
+See pngtest.c for a working example.  Your function will be called
+before any of the other transformations are processed.  If supported
+libpng also supplies an information routine that may be called from
+your callback:
+
+   png_get_current_row_number(png_ptr);
+   png_get_current_pass_number(png_ptr);
+
+This returns the current row passed to the transform.  With interlaced
+images the value returned is the row in the input sub-image image.  Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function.
+
+    png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
+
+The user_channels and user_depth parameters of this function are ignored
+when writing; you can set them to zero as shown.
+
+You can retrieve the pointer via the function png_get_user_transform_ptr().
+For example:
+
+    voidp write_user_transform_ptr =
+       png_get_user_transform_ptr(png_ptr);
+
+It is possible to have libpng flush any pending output, either manually,
+or automatically after a certain number of lines have been written.  To
+flush the output stream a single time call:
+
+    png_write_flush(png_ptr);
+
+and to have libpng flush the output stream periodically after a certain
+number of scanlines have been written, call:
+
+    png_set_flush(png_ptr, nrows);
+
+Note that the distance between rows is from the last time png_write_flush()
+was called, or the first row of the image if it has never been called.
+So if you write 50 lines, and then png_set_flush 25, it will flush the
+output on the next scanline, and every 25 lines thereafter, unless
+png_write_flush() is called before 25 more lines have been written.
+If nrows is too small (less than about 10 lines for a 640 pixel wide
+RGB image) the image compression may decrease noticeably (although this
+may be acceptable for real-time applications).  Infrequent flushing will
+only degrade the compression performance by a few percent over images
+that do not use flushing.
+
+.SS Writing the image data
+
+That's it for the transformations.  Now you can write the image data.
+The simplest way to do this is in one function call.  If you have the
+whole image in memory, you can just call png_write_image() and libpng
+will write the image.  You will need to pass in an array of pointers to
+each row.  This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() or call this function multiple
+times, or any of that other stuff necessary with png_write_rows().
+
+    png_write_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+    png_byte *row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to write the whole image at once, you can
+use png_write_rows() instead.  If the file is not interlaced,
+this is simple:
+
+    png_write_rows(png_ptr, row_pointers,
+       number_of_rows);
+
+row_pointers is the same as in the png_write_image() call.
+
+If you are just writing one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+    png_bytep row_pointer = row;
+
+    png_write_row(png_ptr, row_pointer);
+
+When the file is interlaced, things can get a good deal more complicated.
+The only currently (as of the PNG Specification version 1.2, dated July
+1999) defined interlacing scheme for PNG files is the "Adam7" interlace
+scheme, that breaks down an image into seven smaller images of varying
+size.  libpng will build these images for you, or you can do them
+yourself.  If you want to build them yourself, see the PNG specification
+for details of which pixels to write when.
+
+If you don't want libpng to handle the interlacing details, just
+use png_set_interlace_handling() and call png_write_rows() the
+correct number of times to write all the sub-images
+(png_set_interlace_handling() returns the number of sub-images.)
+
+If you want libpng to build the sub-images, call this before you start
+writing any rows:
+
+    number_of_passes = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed.  Currently, this is seven,
+but may change if another interlace type is added.
+
+Then write the complete image number_of_passes times.
+
+    png_write_rows(png_ptr, row_pointers, number_of_rows);
+
+Think carefully before you write an interlaced image.  Typically code that
+reads such images reads all the image data into memory, uncompressed, before
+doing any processing.  Only code that can display an image on the fly can
+take advantage of the interlacing and even then the image has to be exactly
+the correct size for the output device, because scaling an image requires
+adjacent pixels and these are not available until all the passes have been
+read.
+
+If you do write an interlaced image you will hardly ever need to handle
+the interlacing yourself.  Call png_set_interlace_handling() and use the
+approach described above.
+
+The only time it is conceivable that you will really need to write an
+interlaced image pass-by-pass is when you have read one pass by pass and
+made some pixel-by-pixel transformation to it, as described in the read
+code above.  In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
+to determine the size of each sub-image in turn and simply write the rows
+you obtained from the read code.
+
+.SS Finishing a sequential write
+
+After you are finished writing the image, you should finish writing
+the file.  If you are interested in writing comments or time, you should
+pass an appropriately filled png_info pointer.  If you are not interested,
+you can pass NULL.
+
+    png_write_end(png_ptr, info_ptr);
+
+When you are done, you can free all memory used by libpng like this:
+
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+    png_free_data(png_ptr, info_ptr, mask, seq)
+
+    mask  - identifies data to be freed, a mask
+            containing the bitwise OR of one or
+            more of
+              PNG_FREE_PLTE, PNG_FREE_TRNS,
+              PNG_FREE_HIST, PNG_FREE_ICCP,
+              PNG_FREE_PCAL, PNG_FREE_ROWS,
+              PNG_FREE_SCAL, PNG_FREE_SPLT,
+              PNG_FREE_TEXT, PNG_FREE_UNKN,
+            or simply PNG_FREE_ALL
+
+    seq   - sequence number of item to be freed
+            (\-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user  and not by libpng,  and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed.  If "seq" is not \-1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+If you allocated data such as a palette that you passed in to libpng
+with png_set_*, you must not free it until just before the call to
+png_destroy_write_struct().
+
+The default behavior is only to free data that was allocated internally
+by libpng.  This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+    png_data_freer(png_ptr, info_ptr, freer, mask)
+
+    freer  - one of
+               PNG_DESTROY_WILL_FREE_DATA
+               PNG_SET_WILL_FREE_DATA
+               PNG_USER_WILL_FREE_DATA
+
+    mask   - which data elements are affected
+             same choices as in png_free_data()
+
+For example, to transfer responsibility for some data from a read structure
+to a write structure, you could use
+
+    png_data_freer(read_ptr, read_info_ptr,
+       PNG_USER_WILL_FREE_DATA,
+       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+    png_data_freer(write_ptr, write_info_ptr,
+       PNG_DESTROY_WILL_FREE_DATA,
+       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+thereby briefly reassigning responsibility for freeing to the user but
+immediately afterwards reassigning it once more to the write_destroy
+function.  Having done this, it would then be safe to destroy the read
+structure and continue to use the PLTE, tRNS, and hIST data in the write
+structure.
+
+This function only affects data that has already been allocated.
+You can call this function before calling after the png_set_*() functions
+to control whether the user or png_destroy_*() is supposed to free the data.
+When the user assumes responsibility for libpng-allocated data, the
+application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key.  Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+For a more compact example of writing a PNG image, see the file example.c.
+
+.SH V. Simplified API
+
+The simplified API, which became available in libpng-1.6.0, hides the details
+of both libpng and the PNG file format itself.
+It allows PNG files to be read into a very limited number of
+in-memory bitmap formats or to be written from the same formats.  If these
+formats do not accommodate your needs then you can, and should, use the more
+sophisticated APIs above - these support a wide variety of in-memory formats
+and a wide variety of sophisticated transformations to those formats as well
+as a wide variety of APIs to manipulate ancillary information.
+
+To read a PNG file using the simplified API:
+
+  1) Declare a 'png_image' structure (see below) on the stack, set the
+     version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
+     (this is REQUIRED, your program may crash if you don't do it.)
+
+  2) Call the appropriate png_image_begin_read... function.
+
+  3) Set the png_image 'format' member to the required sample format.
+
+  4) Allocate a buffer for the image and, if required, the color-map.
+
+  5) Call png_image_finish_read to read the image and, if required, the
+     color-map into your buffers.
+
+There are no restrictions on the format of the PNG input itself; all valid
+color types, bit depths, and interlace methods are acceptable, and the
+input image is transformed as necessary to the requested in-memory format
+during the png_image_finish_read() step.  The only caveat is that if you
+request a color-mapped image from a PNG that is full-color or makes
+complex use of an alpha channel the transformation is extremely lossy and the
+result may look terrible.
+
+To write a PNG file using the simplified API:
+
+  1) Declare a 'png_image' structure on the stack and memset()
+     it to all zero.
+
+  2) Initialize the members of the structure that describe the
+     image, setting the 'format' member to the format of the
+     image samples.
+
+  3) Call the appropriate png_image_write... function with a
+     pointer to the image and, if necessary, the color-map to write
+     the PNG data.
+
+png_image is a structure that describes the in-memory format of an image
+when it is being read or defines the in-memory format of an image that you
+need to write.  The "png_image" structure contains the following members:
+
+   png_controlp opaque  Initialize to NULL, free with png_image_free
+   png_uint_32  version Set to PNG_IMAGE_VERSION
+   png_uint_32  width   Image width in pixels (columns)
+   png_uint_32  height  Image height in pixels (rows)
+   png_uint_32  format  Image format as defined below
+   png_uint_32  flags   A bit mask containing informational flags
+   png_uint_32  colormap_entries; Number of entries in the color-map
+   png_uint_32  warning_or_error;
+   char         message[64];
+
+In the event of an error or warning the "warning_or_error"
+field will be set to a non-zero value and the 'message' field will contain
+a '\0' terminated string with the libpng error or warning message.  If both
+warnings and an error were encountered, only the error is recorded.  If there
+are multiple warnings, only the first one is recorded.
+
+The upper 30 bits of the "warning_or_error" value are reserved; the low two
+bits contain a two bit code such that a value more than 1 indicates a failure
+in the API just called:
+
+   0 - no warning or error
+   1 - warning
+   2 - error
+   3 - error preceded by warning
+
+The pixels (samples) of the image have one to four channels whose components
+have original values in the range 0 to 1.0:
+
+  1: A single gray or luminance channel (G).
+  2: A gray/luminance channel and an alpha channel (GA).
+  3: Three red, green, blue color channels (RGB).
+  4: Three color channels and an alpha channel (RGBA).
+
+The channels are encoded in one of two ways:
+
+  a) As a small integer, value 0..255, contained in a single byte.  For the
+alpha channel the original value is simply value/255.  For the color or
+luminance channels the value is encoded according to the sRGB specification
+and matches the 8-bit format expected by typical display devices.
+
+The color/gray channels are not scaled (pre-multiplied) by the alpha
+channel and are suitable for passing to color management software.
+
+  b) As a value in the range 0..65535, contained in a 2-byte integer, in
+the native byte order of the platform on which the application is running.
+All channels can be converted to the original value by dividing by 65535; all
+channels are linear.  Color channels use the RGB encoding (RGB end-points) of
+the sRGB specification.  This encoding is identified by the
+PNG_FORMAT_FLAG_LINEAR flag below.
+
+When the simplified API needs to convert between sRGB and linear colorspaces,
+the actual sRGB transfer curve defined in the sRGB specification (see the
+article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+approximation used elsewhere in libpng.
+
+When an alpha channel is present it is expected to denote pixel coverage
+of the color or luminance channels and is returned as an associated alpha
+channel: the color/gray channels are scaled (pre-multiplied) by the alpha
+value.
+
+The samples are either contained directly in the image data, between 1 and 8
+bytes per pixel according to the encoding, or are held in a color-map indexed
+by bytes in the image data.  In the case of a color-map the color-map entries
+are individual samples, encoded as above, and the image data has one byte per
+pixel to select the relevant sample from the color-map.
+
+PNG_FORMAT_*
+
+The #defines to be used in png_image::format.  Each #define identifies a
+particular layout of channel data and, if present, alpha values.  There are
+separate defines for each of the two component encodings.
+
+A format is built up using single bit flag values.  All combinations are
+valid.  Formats can be built up from the flag values or you can use one of
+the predefined values below.  When testing formats always use the FORMAT_FLAG
+macros to test for individual features - future versions of the library may
+add new flags.
+
+When reading or writing color-mapped images the format should be set to the
+format of the entries in the color-map then png_image_{read,write}_colormap
+called to read or write the color-map and set the format correctly for the
+image data.  Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
+
+NOTE: libpng can be built with particular features disabled. If you see
+compiler errors because the definition of one of the following flags has been
+compiled out it is because libpng does not have the required support.  It is
+possible, however, for the libpng configuration to enable the format on just
+read or just write; in that case you may see an error at run time.
+You can guard against this by checking for the definition of the
+appropriate "_SUPPORTED" macro, one of:
+
+   PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
+
+   PNG_FORMAT_FLAG_ALPHA    format with an alpha channel
+   PNG_FORMAT_FLAG_COLOR    color format: otherwise grayscale
+   PNG_FORMAT_FLAG_LINEAR   2-byte channels else 1-byte
+   PNG_FORMAT_FLAG_COLORMAP image data is color-mapped
+   PNG_FORMAT_FLAG_BGR      BGR colors, else order is RGB
+   PNG_FORMAT_FLAG_AFIRST   alpha channel comes first
+
+Supported formats are as follows.  Future versions of libpng may support more
+formats; for compatibility with older versions simply check if the format
+macro is defined using #ifdef.  These defines describe the in-memory layout
+of the components of the pixels of the image.
+
+First the single byte (sRGB) formats:
+
+   PNG_FORMAT_GRAY
+   PNG_FORMAT_GA
+   PNG_FORMAT_AG
+   PNG_FORMAT_RGB
+   PNG_FORMAT_BGR
+   PNG_FORMAT_RGBA
+   PNG_FORMAT_ARGB
+   PNG_FORMAT_BGRA
+   PNG_FORMAT_ABGR
+
+Then the linear 2-byte formats.  When naming these "Y" is used to
+indicate a luminance (gray) channel.  The component order within the pixel
+is always the same - there is no provision for swapping the order of the
+components in the linear format.  The components are 16-bit integers in
+the native byte order for your platform, and there is no provision for
+swapping the bytes to a different endian condition.
+
+   PNG_FORMAT_LINEAR_Y
+   PNG_FORMAT_LINEAR_Y_ALPHA
+   PNG_FORMAT_LINEAR_RGB
+   PNG_FORMAT_LINEAR_RGB_ALPHA
+
+With color-mapped formats the image data is one byte for each pixel. The byte
+is an index into the color-map which is formatted as above.  To obtain a
+color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
+to one of the above definitions, or you can use one of the definitions below.
+
+   PNG_FORMAT_RGB_COLORMAP
+   PNG_FORMAT_BGR_COLORMAP
+   PNG_FORMAT_RGBA_COLORMAP
+   PNG_FORMAT_ARGB_COLORMAP
+   PNG_FORMAT_BGRA_COLORMAP
+   PNG_FORMAT_ABGR_COLORMAP
+
+PNG_IMAGE macros
+
+These are convenience macros to derive information from a png_image
+structure.  The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
+actual image sample values - either the entries in the color-map or the
+pixels in the image.  The PNG_IMAGE_PIXEL_ macros return corresponding values
+for the pixels and will always return 1 for color-mapped formats.  The
+remaining macros return information about the rows in the image and the
+complete image.
+
+NOTE: All the macros that take a png_image::format parameter are compile time
+constants if the format parameter is, itself, a constant.  Therefore these
+macros can be used in array declarations and case labels where required.
+Similarly the macros are also pre-processor constants (sizeof is not used) so
+they can be used in #if tests.
+
+  PNG_IMAGE_SAMPLE_CHANNELS(fmt)
+    Returns the total number of channels in a given format: 1..4
+
+  PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)
+    Returns the size in bytes of a single component of a pixel or color-map
+    entry (as appropriate) in the image: 1 or 2.
+
+  PNG_IMAGE_SAMPLE_SIZE(fmt)
+    This is the size of the sample data for one sample.  If the image is
+    color-mapped it is the size of one color-map entry (and image pixels are
+    one byte in size), otherwise it is the size of one image pixel.
+
+  PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)
+    The maximum size of the color-map required by the format expressed in a
+    count of components.  This can be used to compile-time allocate a
+    color-map:
+
+    png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
+
+    png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
+
+    Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+    information from one of the png_image_begin_read_ APIs and dynamically
+    allocate the required memory.
+
+  PNG_IMAGE_COLORMAP_SIZE(fmt)
+   The size of the color-map required by the format; this is the size of the
+   color-map buffer passed to the png_image_{read,write}_colormap APIs. It is
+   a fixed number determined by the format so can easily be allocated on the
+   stack if necessary.
+
+Corresponding information about the pixels
+
+  PNG_IMAGE_PIXEL_CHANNELS(fmt)
+   The number of separate channels (components) in a pixel; 1 for a
+   color-mapped image.
+
+  PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
+   The size, in bytes, of each component in a pixel; 1 for a color-mapped
+   image.
+
+  PNG_IMAGE_PIXEL_SIZE(fmt)
+   The size, in bytes, of a complete pixel; 1 for a color-mapped image.
+
+Information about the whole row, or whole image
+
+  PNG_IMAGE_ROW_STRIDE(image)
+   Returns the total number of components in a single row of the image; this
+   is the minimum 'row stride', the minimum count of components between each
+   row.  For a color-mapped image this is the minimum number of bytes in a
+   row.
+
+   If you need the stride measured in bytes, row_stride_bytes is
+   PNG_IMAGE_ROW_STRIDE(image) * PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)
+   plus any padding bytes that your application might need, for example
+   to start the next row on a 4-byte boundary.
+
+  PNG_IMAGE_BUFFER_SIZE(image, row_stride)
+   Return the size, in bytes, of an image buffer given a png_image and a row
+   stride - the number of components to leave space for in each row.
+
+  PNG_IMAGE_SIZE(image)
+   Return the size, in bytes, of the image in memory given just a png_image;
+   the row stride is the minimum stride required for the image.
+
+  PNG_IMAGE_COLORMAP_SIZE(image)
+   Return the size, in bytes, of the color-map of this image.  If the image
+   format is not a color-map format this will return a size sufficient for
+   256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
+   you don't want to allocate a color-map in this case.
+
+PNG_IMAGE_FLAG_*
+
+Flags containing additional information about the image are held in
+the 'flags' field of png_image.
+
+  PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01
+    This indicates that the RGB values of the in-memory bitmap do not
+    correspond to the red, green and blue end-points defined by sRGB.
+
+  PNG_IMAGE_FLAG_FAST == 0x02
+   On write emphasise speed over compression; the resultant PNG file will be
+   larger but will be produced significantly faster, particular for large
+   images.  Do not use this option for images which will be distributed, only
+   used it when producing intermediate files that will be read back in
+   repeatedly.  For a typical 24-bit image the option will double the read
+   speed at the cost of increasing the image size by 25%, however for many
+   more compressible images the PNG file can be 10 times larger with only a
+   slight speed gain.
+
+  PNG_IMAGE_FLAG_16BIT_sRGB == 0x04
+    On read if the image is a 16-bit per component image and there is no gAMA
+    or sRGB chunk assume that the components are sRGB encoded.  Notice that
+    images output by the simplified API always have gamma information; setting
+    this flag only affects the interpretation of 16-bit images from an
+    external source.  It is recommended that the application expose this flag
+    to the user; the user can normally easily recognize the difference between
+    linear and sRGB encoding.  This flag has no effect on write - the data
+    passed to the write APIs must have the correct encoding (as defined
+    above.)
+
+    If the flag is not set (the default) input 16-bit per component data is
+    assumed to be linear.
+
+    NOTE: the flag can only be set after the png_image_begin_read_ call,
+    because that call initializes the 'flags' field.
+
+READ APIs
+
+   The png_image passed to the read APIs must have been initialized by setting
+   the png_controlp field 'opaque' to NULL (or, better, memset the whole thing.)
+
+   int png_image_begin_read_from_file( png_imagep image,
+     const char *file_name)
+
+     The named file is opened for read and the image header
+     is filled in from the PNG header in the file.
+
+   int png_image_begin_read_from_stdio (png_imagep image,
+     FILE* file)
+
+      The PNG header is read from the stdio FILE object.
+
+   int png_image_begin_read_from_memory(png_imagep image,
+      png_const_voidp memory, size_t size)
+
+      The PNG header is read from the given memory buffer.
+
+   int png_image_finish_read(png_imagep image,
+      png_colorp background, void *buffer,
+      png_int_32 row_stride, void *colormap));
+
+      Finish reading the image into the supplied buffer and
+      clean up the png_image structure.
+
+      row_stride is the step, in png_byte or png_uint_16 units
+      as appropriate, between adjacent rows.  A positive stride
+      indicates that the top-most row is first in the buffer -
+      the normal top-down arrangement.  A negative stride
+      indicates that the bottom-most row is first in the buffer.
+
+      background need only be supplied if an alpha channel must
+      be removed from a png_byte format and the removal is to be
+      done by compositing on a solid color; otherwise it may be
+      NULL and any composition will be done directly onto the
+      buffer.  The value is an sRGB color to use for the
+      background, for grayscale output the green channel is used.
+
+      For linear output removing the alpha channel is always done
+      by compositing on black.
+
+   void png_image_free(png_imagep image)
+
+      Free any data allocated by libpng in image->opaque,
+      setting the pointer to NULL.  May be called at any time
+      after the structure is initialized.
+
+When the simplified API needs to convert between sRGB and linear colorspaces,
+the actual sRGB transfer curve defined in the sRGB specification (see the
+article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+approximation used elsewhere in libpng.
+
+WRITE APIS
+
+For write you must initialize a png_image structure to describe the image to
+be written:
+
+   version: must be set to PNG_IMAGE_VERSION
+   opaque: must be initialized to NULL
+   width: image width in pixels
+   height: image height in rows
+   format: the format of the data you wish to write
+   flags: set to 0 unless one of the defined flags applies; set
+      PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images
+      where the RGB values do not correspond to the colors in sRGB.
+   colormap_entries: set to the number of entries in the color-map (0 to 256)
+
+   int png_image_write_to_file, (png_imagep image,
+      const char *file, int convert_to_8bit, const void *buffer,
+      png_int_32 row_stride, const void *colormap));
+
+      Write the image to the named file.
+
+   int png_image_write_to_memory (png_imagep image, void *memory,
+      png_alloc_size_t * PNG_RESTRICT memory_bytes,
+      int convert_to_8_bit, const void *buffer, ptrdiff_t row_stride,
+      const void *colormap));
+
+      Write the image to memory.
+
+   int png_image_write_to_stdio(png_imagep image, FILE *file,
+      int convert_to_8_bit, const void *buffer,
+      png_int_32 row_stride, const void *colormap)
+
+      Write the image to the given (FILE*).
+
+With all write APIs if image is in one of the linear formats with
+(png_uint_16) data then setting convert_to_8_bit will cause the output to be
+a (png_byte) PNG gamma encoded according to the sRGB specification, otherwise
+a 16-bit linear encoded PNG file is written.
+
+With all APIs row_stride is handled as in the read APIs - it is the spacing
+from one row to the next in component sized units (float) and if negative
+indicates a bottom-up row layout in the buffer.  If you pass zero, libpng will
+calculate the row_stride for you from the width and number of channels.
+
+Note that the write API does not support interlacing, sub-8-bit pixels,
+indexed (paletted) images, or most ancillary chunks.
+
+.SH VI. Modifying/Customizing libpng
+
+There are two issues here.  The first is changing how libpng does
+standard things like memory allocation, input/output, and error handling.
+The second deals with more complicated things like adding new chunks,
+adding new transformations, and generally changing how libpng works.
+Both of those are compile-time issues; that is, they are generally
+determined at the time the code is written, and there is rarely a need
+to provide the user with a means of changing them.
+
+Memory allocation, input/output, and error handling
+
+All of the memory allocation, input/output, and error handling in libpng
+goes through callbacks that are user-settable.  The default routines are
+in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively.  To change
+these functions, call the appropriate png_set_*_fn() function.
+
+Memory allocation is done through the functions png_malloc(), png_calloc(),
+and png_free().  The png_malloc() and png_free() functions currently just
+call the standard C functions and png_calloc() calls png_malloc() and then
+clears the newly allocated memory to zero; note that png_calloc(png_ptr, size)
+is not the same as the calloc(number, size) function provided by stdlib.h.
+There is limited support for certain systems with segmented memory
+architectures and the types of pointers declared by png.h match this; you
+will have to use appropriate pointers in your application.  If you prefer
+to use a different method of allocating and freeing data, you can use
+png_create_read_struct_2() or png_create_write_struct_2() to register your
+own functions as described above.  These functions also provide a void
+pointer that can be retrieved via
+
+    mem_ptr=png_get_mem_ptr(png_ptr);
+
+Your replacement memory functions must have prototypes as follows:
+
+    png_voidp malloc_fn(png_structp png_ptr,
+       png_alloc_size_t size);
+
+    void free_fn(png_structp png_ptr, png_voidp ptr);
+
+Your malloc_fn() must return NULL in case of failure.  The png_malloc()
+function will normally call png_error() if it receives a NULL from the
+system memory allocator or from your replacement malloc_fn().
+
+Your free_fn() will never be called with a NULL ptr, since libpng's
+png_free() checks for NULL before calling free_fn().
+
+Input/Output in libpng is done through png_read() and png_write(),
+which currently just call fread() and fwrite().  The FILE * is stored in
+png_struct and is initialized via png_init_io().  If you wish to change
+the method of I/O, the library supplies callbacks that you can set
+through the function png_set_read_fn() and png_set_write_fn() at run
+time, instead of calling the png_init_io() function.  These functions
+also provide a void pointer that can be retrieved via the function
+png_get_io_ptr().  For example:
+
+    png_set_read_fn(png_structp read_ptr,
+        voidp read_io_ptr, png_rw_ptr read_data_fn)
+
+    png_set_write_fn(png_structp write_ptr,
+        voidp write_io_ptr, png_rw_ptr write_data_fn,
+        png_flush_ptr output_flush_fn);
+
+    voidp read_io_ptr = png_get_io_ptr(read_ptr);
+    voidp write_io_ptr = png_get_io_ptr(write_ptr);
+
+The replacement I/O functions must have prototypes as follows:
+
+    void user_read_data(png_structp png_ptr,
+        png_bytep data, size_t length);
+
+    void user_write_data(png_structp png_ptr,
+        png_bytep data, size_t length);
+
+    void user_flush_data(png_structp png_ptr);
+
+The user_read_data() function is responsible for detecting and
+handling end-of-data errors.
+
+Supplying NULL for the read, write, or flush functions sets them back
+to using the default C stream functions, which expect the io_ptr to
+point to a standard *FILE structure.  It is probably a mistake
+to use NULL for one of write_data_fn and output_flush_fn but not both
+of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
+It is an error to read from a write stream, and vice versa.
+
+Error handling in libpng is done through png_error() and png_warning().
+Errors handled through png_error() are fatal, meaning that png_error()
+should never return to its caller.  Currently, this is handled via
+setjmp() and longjmp() (unless you have compiled libpng with
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
+but you could change this to do things like exit() if you should wish,
+as long as your function does not return.
+
+On non-fatal errors, png_warning() is called
+to print a warning message, and then control returns to the calling code.
+By default png_error() and png_warning() print a message on stderr via
+fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
+(because you don't want the messages) or PNG_NO_STDIO defined (because
+fprintf() isn't available).  If you wish to change the behavior of the error
+functions, you will need to set up your own message callbacks.  These
+functions are normally supplied at the time that the png_struct is created.
+It is also possible to redirect errors and warnings to your own replacement
+functions after png_create_*_struct() has been called by calling:
+
+    png_set_error_fn(png_structp png_ptr,
+        png_voidp error_ptr, png_error_ptr error_fn,
+        png_error_ptr warning_fn);
+
+If NULL is supplied for either error_fn or warning_fn, then the libpng
+default function will be used, calling fprintf() and/or longjmp() if a
+problem is encountered.  The replacement error functions should have
+parameters as follows:
+
+    void user_error_fn(png_structp png_ptr,
+        png_const_charp error_msg);
+
+    void user_warning_fn(png_structp png_ptr,
+        png_const_charp warning_msg);
+
+Then, within your user_error_fn or user_warning_fn, you can retrieve
+the error_ptr if you need it, by calling
+
+    png_voidp error_ptr = png_get_error_ptr(png_ptr);
+
+The motivation behind using setjmp() and longjmp() is the C++ throw and
+catch exception handling methods.  This makes the code much easier to write,
+as there is no need to check every return code of every function call.
+However, there are some uncertainties about the status of local variables
+after a longjmp, so the user may want to be careful about doing anything
+after setjmp returns non-zero besides returning itself.  Consult your
+compiler documentation for more details.  For an alternative approach, you
+may wish to use the "cexcept" facility (see https://cexcept.sourceforge.io/),
+which is illustrated in pngvalid.c and in contrib/visupng.
+
+Beginning in libpng-1.4.0, the png_set_benign_errors() API became available.
+You can use this to handle certain errors (normally handled as errors)
+as warnings.
+
+    png_set_benign_errors (png_ptr, int allowed);
+
+    allowed: 0: treat png_benign_error() as an error.
+             1: treat png_benign_error() as a warning.
+
+As of libpng-1.6.0, the default condition is to treat benign errors as
+warnings while reading and as errors while writing.
+
+.SS Custom chunks
+
+If you need to read or write custom chunks, you may need to get deeper
+into the libpng code.  The library now has mechanisms for storing
+and writing chunks of unknown type; you can even declare callbacks
+for custom chunks.  However, this may not be good enough if the
+library code itself needs to know about interactions between your
+chunk and existing `intrinsic' chunks.
+
+If you need to write a new intrinsic chunk, first read the PNG
+specification. Acquire a first level of understanding of how it works.
+Pay particular attention to the sections that describe chunk names,
+and look at how other chunks were designed, so you can do things
+similarly.  Second, check out the sections of libpng that read and
+write chunks.  Try to find a chunk that is similar to yours and use
+it as a template.  More details can be found in the comments inside
+the code.  It is best to handle private or unknown chunks in a generic method,
+via callback functions, instead of by modifying libpng functions. This
+is illustrated in pngtest.c, which uses a callback function to handle a
+private "vpAg" chunk and the new "sTER" chunk, which are both unknown to
+libpng.
+
+If you wish to write your own transformation for the data, look through
+the part of the code that does the transformations, and check out some of
+the simpler ones to get an idea of how they work.  Try to find a similar
+transformation to the one you want to add and copy off of it.  More details
+can be found in the comments inside the code itself.
+
+.SS Configuring for gui/windowing platforms:
+
+You will need to write new error and warning functions that use the GUI
+interface, as described previously, and set them to be the error and
+warning functions at the time that png_create_*_struct() is called,
+in order to have them available during the structure initialization.
+They can be changed later via png_set_error_fn().  On some compilers,
+you may also have to change the memory allocators (png_malloc, etc.).
+
+.SS Configuring zlib:
+
+There are special functions to configure the compression.  Perhaps the
+most useful one changes the compression level, which currently uses
+input compression values in the range 0 - 9.  The library normally
+uses the default compression level (Z_DEFAULT_COMPRESSION = 6).  Tests
+have shown that for a large majority of images, compression values in
+the range 3-6 compress nearly as well as higher levels, and do so much
+faster.  For online applications it may be desirable to have maximum speed
+(Z_BEST_SPEED = 1).  With versions of zlib after v0.99, you can also
+specify no compression (Z_NO_COMPRESSION = 0), but this would create
+files larger than just storing the raw bitmap.  You can specify the
+compression level by calling:
+
+    #include zlib.h
+    png_set_compression_level(png_ptr, level);
+
+Another useful one is to reduce the memory level used by the library.
+The memory level defaults to 8, but it can be lowered if you are
+short on memory (running DOS, for example, where you only have 640K).
+Note that the memory level does have an effect on compression; among
+other things, lower levels will result in sections of incompressible
+data being emitted in smaller stored blocks, with a correspondingly
+larger relative overhead of up to 15% in the worst case.
+
+    #include zlib.h
+    png_set_compression_mem_level(png_ptr, level);
+
+The other functions are for configuring zlib.  They are not recommended
+for normal use and may result in writing an invalid PNG file.  See
+zlib.h for more information on what these mean.
+
+    #include zlib.h
+    png_set_compression_strategy(png_ptr,
+        strategy);
+
+    png_set_compression_window_bits(png_ptr,
+        window_bits);
+
+    png_set_compression_method(png_ptr, method);
+
+This controls the size of the IDAT chunks (default 8192):
+
+    png_set_compression_buffer_size(png_ptr, size);
+
+As of libpng version 1.5.4, additional APIs became
+available to set these separately for non-IDAT
+compressed chunks such as zTXt, iTXt, and iCCP:
+
+    #include zlib.h
+    #if PNG_LIBPNG_VER >= 10504
+    png_set_text_compression_level(png_ptr, level);
+
+    png_set_text_compression_mem_level(png_ptr, level);
+
+    png_set_text_compression_strategy(png_ptr,
+        strategy);
+
+    png_set_text_compression_window_bits(png_ptr,
+        window_bits);
+
+    png_set_text_compression_method(png_ptr, method);
+    #endif
+
+.SS Controlling row filtering
+
+If you want to control whether libpng uses filtering or not, which
+filters are used, and how it goes about picking row filters, you
+can call one of these functions.  The selection and configuration
+of row filters can have a significant impact on the size and
+encoding speed and a somewhat lesser impact on the decoding speed
+of an image.  Filtering is enabled by default for RGB and grayscale
+images (with and without alpha), but not for paletted images nor
+for any images with bit depths less than 8 bits/pixel.
+
+The 'method' parameter sets the main filtering method, which is
+currently only '0' in the PNG 1.2 specification.  The 'filters'
+parameter sets which filter(s), if any, should be used for each
+scanline.  Possible values are PNG_ALL_FILTERS, PNG_NO_FILTERS,
+or PNG_FAST_FILTERS to turn filtering on and off, or to turn on
+just the fast-decoding subset of filters, respectively.
+
+Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
+PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
+ORed together with '|' to specify one or more filters to use.
+These filters are described in more detail in the PNG specification.
+If you intend to change the filter type during the course of writing
+the image, you should start with flags set for all of the filters
+you intend to use so that libpng can initialize its internal
+structures appropriately for all of the filter types.  (Note that this
+means the first row must always be adaptively filtered, because libpng
+currently does not allocate the filter buffers until png_write_row()
+is called for the first time.)
+
+    filters = PNG_NO_FILTERS;
+    filters = PNG_ALL_FILTERS;
+    filters = PNG_FAST_FILTERS;
+
+    or
+
+    filters = PNG_FILTER_NONE | PNG_FILTER_SUB |
+              PNG_FILTER_UP | PNG_FILTER_AVG |
+              PNG_FILTER_PAETH;
+
+    png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
+       filters);
+
+              The second parameter can also be
+              PNG_INTRAPIXEL_DIFFERENCING if you are
+              writing a PNG to be embedded in a MNG
+              datastream.  This parameter must be the
+              same as the value of filter_method used
+              in png_set_IHDR().
+
+.SS Requesting debug printout
+
+The macro definition PNG_DEBUG can be used to request debugging
+printout.  Set it to an integer value in the range 0 to 3.  Higher
+numbers result in increasing amounts of debugging information.  The
+information is printed to the "stderr" file, unless another file
+name is specified in the PNG_DEBUG_FILE macro definition.
+
+When PNG_DEBUG > 0, the following functions (macros) become available:
+
+   png_debug(level, message)
+   png_debug1(level, message, p1)
+   png_debug2(level, message, p1, p2)
+
+in which "level" is compared to PNG_DEBUG to decide whether to print
+the message, "message" is the formatted string to be printed,
+and p1 and p2 are parameters that are to be embedded in the string
+according to printf-style formatting directives.  For example,
+
+   png_debug1(2, "foo=%d", foo);
+
+is expanded to
+
+   if (PNG_DEBUG > 2)
+      fprintf(PNG_DEBUG_FILE, "foo=%d\en", foo);
+
+When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
+can still use PNG_DEBUG to control your own debugging:
+
+   #ifdef PNG_DEBUG
+       fprintf(stderr, ...
+   #endif
+
+When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
+having level = 0 will be printed.  There aren't any such statements in
+this version of libpng, but if you insert some they will be printed.
+
+.SH VII. MNG support
+
+The MNG specification (available at http://www.libpng.org/pub/mng) allows
+certain extensions to PNG for PNG images that are embedded in MNG datastreams.
+Libpng can support some of these extensions.  To enable them, use the
+png_permit_mng_features() function:
+
+   feature_set = png_permit_mng_features(png_ptr, mask)
+
+   mask is a png_uint_32 containing the bitwise OR of the
+        features you want to enable.  These include
+        PNG_FLAG_MNG_EMPTY_PLTE
+        PNG_FLAG_MNG_FILTER_64
+        PNG_ALL_MNG_FEATURES
+
+   feature_set is a png_uint_32 that is the bitwise AND of
+      your mask with the set of MNG features that is
+      supported by the version of libpng that you are using.
+
+It is an error to use this function when reading or writing a standalone
+PNG file with the PNG 8-byte signature.  The PNG datastream must be wrapped
+in a MNG datastream.  As a minimum, it must have the MNG 8-byte signature
+and the MHDR and MEND chunks.  Libpng does not provide support for these
+or any other MNG chunks; your application must provide its own support for
+them.  You may wish to consider using libmng (available at
+https://www.libmng.com/) instead.
+
+.SH VIII. Changes to Libpng from version 0.88
+
+It should be noted that versions of libpng later than 0.96 are not
+distributed by the original libpng author, Guy Schalnat, nor by
+Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
+distributed versions 0.89 through 0.96, but rather by another member
+of the original PNG Group, Glenn Randers-Pehrson.  Guy and Andreas are
+still alive and well, but they have moved on to other things.
+
+The old libpng functions png_read_init(), png_write_init(),
+png_info_init(), png_read_destroy(), and png_write_destroy() have been
+moved to PNG_INTERNAL in version 0.95 to discourage their use.  These
+functions will be removed from libpng version 1.4.0.
+
+The preferred method of creating and initializing the libpng structures is
+via the png_create_read_struct(), png_create_write_struct(), and
+png_create_info_struct() because they isolate the size of the structures
+from the application, allow version error checking, and also allow the
+use of custom error handling routines during the initialization, which
+the old functions do not.  The functions png_read_destroy() and
+png_write_destroy() do not actually free the memory that libpng
+allocated for these structs, but just reset the data structures, so they
+can be used instead of png_destroy_read_struct() and
+png_destroy_write_struct() if you feel there is too much system overhead
+allocating and freeing the png_struct for each image read.
+
+Setting the error callbacks via png_set_message_fn() before
+png_read_init() as was suggested in libpng-0.88 is no longer supported
+because this caused applications that do not use custom error functions
+to fail if the png_ptr was not initialized to zero.  It is still possible
+to set the error callbacks AFTER png_read_init(), or to change them with
+png_set_error_fn(), which is essentially the same function, but with a new
+name to force compilation errors with applications that try to use the old
+method.
+
+Support for the sCAL, iCCP, iTXt, and sPLT chunks was added at libpng-1.0.6;
+however, iTXt support was not enabled by default.
+
+Starting with version 1.0.7, you can find out which version of the library
+you are using at run-time:
+
+   png_uint_32 libpng_vn = png_access_version_number();
+
+The number libpng_vn is constructed from the major version, minor
+version with leading zero, and release number with leading zero,
+(e.g., libpng_vn for version 1.0.7 is 10007).
+
+Note that this function does not take a png_ptr, so you can call it
+before you've created one.
+
+You can also check which version of png.h you used when compiling your
+application:
+
+   png_uint_32 application_vn = PNG_LIBPNG_VER;
+
+.SH IX. Changes to Libpng from version 1.0.x to 1.2.x
+
+Support for user memory management was enabled by default.  To
+accomplish this, the functions png_create_read_struct_2(),
+png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
+png_malloc_default(), and png_free_default() were added.
+
+Support for the iTXt chunk has been enabled by default as of
+version 1.2.41.
+
+Support for certain MNG features was enabled.
+
+Support for numbered error messages was added.  However, we never got
+around to actually numbering the error messages.  The function
+png_set_strip_error_numbers() was added (Note: the prototype for this
+function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
+builds of libpng-1.2.15.  It was restored in libpng-1.2.36).
+
+The png_malloc_warn() function was added at libpng-1.2.3.  This issues
+a png_warning and returns NULL instead of aborting when it fails to
+acquire the requested memory allocation.
+
+Support for setting user limits on image width and height was enabled
+by default.  The functions png_set_user_limits(), png_get_user_width_max(),
+and png_get_user_height_max() were added at libpng-1.2.6.
+
+The png_set_add_alpha() function was added at libpng-1.2.7.
+
+The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
+Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
+tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
+deprecated.
+
+A number of macro definitions in support of runtime selection of
+assembler code features (especially Intel MMX code support) were
+added at libpng-1.2.0:
+
+    PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
+    PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+    PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
+    PNG_ASM_FLAG_MMX_READ_INTERLACE
+    PNG_ASM_FLAG_MMX_READ_FILTER_SUB
+    PNG_ASM_FLAG_MMX_READ_FILTER_UP
+    PNG_ASM_FLAG_MMX_READ_FILTER_AVG
+    PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
+    PNG_ASM_FLAGS_INITIALIZED
+    PNG_MMX_READ_FLAGS
+    PNG_MMX_FLAGS
+    PNG_MMX_WRITE_FLAGS
+    PNG_MMX_FLAGS
+
+We added the following functions in support of runtime
+selection of assembler code features:
+
+    png_get_mmx_flagmask()
+    png_set_mmx_thresholds()
+    png_get_asm_flags()
+    png_get_mmx_bitdepth_threshold()
+    png_get_mmx_rowbytes_threshold()
+    png_set_asm_flags()
+
+We replaced all of these functions with simple stubs in libpng-1.2.20,
+when the Intel assembler code was removed due to a licensing issue.
+
+These macros are deprecated:
+
+    PNG_READ_TRANSFORMS_NOT_SUPPORTED
+    PNG_PROGRESSIVE_READ_NOT_SUPPORTED
+    PNG_NO_SEQUENTIAL_READ_SUPPORTED
+    PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
+    PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
+    PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+They have been replaced, respectively, by:
+
+    PNG_NO_READ_TRANSFORMS
+    PNG_NO_PROGRESSIVE_READ
+    PNG_NO_SEQUENTIAL_READ
+    PNG_NO_WRITE_TRANSFORMS
+    PNG_NO_READ_ANCILLARY_CHUNKS
+    PNG_NO_WRITE_ANCILLARY_CHUNKS
+
+PNG_MAX_UINT was replaced with PNG_UINT_31_MAX.  It has been
+deprecated since libpng-1.0.16 and libpng-1.2.6.
+
+The function
+    png_check_sig(sig, num)
+was replaced with
+    !png_sig_cmp(sig, 0, num)
+It has been deprecated since libpng-0.90.
+
+The function
+    png_set_gray_1_2_4_to_8()
+which also expands tRNS to alpha was replaced with
+    png_set_expand_gray_1_2_4_to_8()
+which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
+
+.SH X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+
+Private libpng prototypes and macro definitions were moved from
+png.h and pngconf.h into a new pngpriv.h header file.
+
+Functions png_set_benign_errors(), png_benign_error(), and
+png_chunk_benign_error() were added.
+
+Support for setting the maximum amount of memory that the application
+will allocate for reading chunks was added, as a security measure.
+The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
+were added to the library.
+
+We implemented support for I/O states by adding png_ptr member io_state
+and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+
+We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
+input transforms.
+
+Checking for and reporting of errors in the IHDR chunk is more thorough.
+
+Support for global arrays was removed, to improve thread safety.
+
+Some obsolete/deprecated macros and functions have been removed.
+
+Typecasted NULL definitions such as
+   #define png_voidp_NULL            (png_voidp)NULL
+were eliminated.  If you used these in your application, just use
+NULL instead.
+
+The png_struct and info_struct members "trans" and "trans_values" were
+changed to "trans_alpha" and "trans_color", respectively.
+
+The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
+were removed.
+
+The PNG_1_0_X and PNG_1_2_X macros were eliminated.
+
+The PNG_LEGACY_SUPPORTED macro was eliminated.
+
+Many WIN32_WCE #ifdefs were removed.
+
+The functions png_read_init(info_ptr), png_write_init(info_ptr),
+png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
+have been removed.  They have been deprecated since libpng-0.95.
+
+The png_permit_empty_plte() was removed. It has been deprecated
+since libpng-1.0.9.  Use png_permit_mng_features() instead.
+
+We removed the obsolete stub functions png_get_mmx_flagmask(),
+png_set_mmx_thresholds(), png_get_asm_flags(),
+png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
+png_set_asm_flags(), and png_mmx_supported()
+
+We removed the obsolete png_check_sig(), png_memcpy_check(), and
+png_memset_check() functions.  Instead use !png_sig_cmp(), memcpy(),
+and memset(), respectively.
+
+The function png_set_gray_1_2_4_to_8() was removed. It has been
+deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
+png_set_expand_gray_1_2_4_to_8() because the former function also
+expanded any tRNS chunk to an alpha channel.
+
+Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32
+were added and are used by default instead of the corresponding
+functions. Unfortunately,
+from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+
+We changed the prototype for png_malloc() from
+    png_malloc(png_structp png_ptr, png_uint_32 size)
+to
+    png_malloc(png_structp png_ptr, png_alloc_size_t size)
+
+This also applies to the prototype for the user replacement malloc_fn().
+
+The png_calloc() function was added and is used in place of
+of "png_malloc(); memset();" except in the case in png_read_png()
+where the array consists of pointers; in this case a "for" loop is used
+after the png_malloc() to set the pointers to NULL, to give robust.
+behavior in case the application runs out of memory part-way through
+the process.
+
+We changed the prototypes of png_get_compression_buffer_size() and
+png_set_compression_buffer_size() to work with size_t instead of
+png_uint_32.
+
+Support for numbered error messages was removed by default, since we
+never got around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was removed from the library by default.
+
+The png_zalloc() and png_zfree() functions are no longer exported.
+The png_zalloc() function no longer zeroes out the memory that it
+allocates.  Applications that called png_zalloc(png_ptr, number, size)
+can call png_calloc(png_ptr, number*size) instead, and can call
+png_free() instead of png_zfree().
+
+Support for dithering was disabled by default in libpng-1.4.0, because
+it has not been well tested and doesn't actually "dither".
+The code was not
+removed, however, and could be enabled by building libpng with
+PNG_READ_DITHER_SUPPORTED defined.  In libpng-1.4.2, this support
+was re-enabled, but the function was renamed png_set_quantize() to
+reflect more accurately what it actually does.  At the same time,
+the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
+PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED
+was renamed to PNG_READ_QUANTIZE_SUPPORTED.
+
+We removed the trailing '.' from the warning and error messages.
+
+.SH XI. Changes to Libpng from version 1.4.x to 1.5.x
+
+From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+The incorrect macro was removed from libpng-1.4.5.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+   png_set_check_for_invalid_index(png_ptr, allowed);
+
+      allowed  - one of
+                 0: disable benign error (accept the
+                    invalid data without warning).
+                 1: enable benign error (treat the
+                    invalid data as an error or a
+                    warning).
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are decoded as opaque black by the decoder and written
+as-is by the encoder.
+
+Retrieving the maximum palette index found was added at libpng-1.5.15.
+This statement must appear after png_read_png() or png_read_image() while
+reading, and after png_write_png() or png_write_image() while writing.
+
+   int max_palette = png_get_palette_max(png_ptr, info_ptr);
+
+This will return the maximum palette index found in the image, or "\-1" if
+the palette was not checked, or "0" if no palette was found.  Note that this
+does not account for any palette index used by ancillary chunks such as the
+bKGD chunk; you must check those separately to determine the maximum
+palette index actually used.
+
+There are no substantial API changes between the non-deprecated parts of
+the 1.4.5 API and the 1.5.0 API; however, the ability to directly access
+members of the main libpng control structures, png_struct and png_info,
+deprecated in earlier versions of libpng, has been completely removed from
+libpng 1.5, and new private "pngstruct.h", "pnginfo.h", and "pngdebug.h"
+header files were created.
+
+We no longer include zlib.h in png.h.  The include statement has been moved
+to pngstruct.h, where it is not accessible by applications. Applications that
+need access to information in zlib.h will need to add the '#include "zlib.h"'
+directive.  It does not matter whether this is placed prior to or after
+the '"#include png.h"' directive.
+
+The png_sprintf(), png_strcpy(), and png_strncpy() macros are no longer used
+and were removed.
+
+We moved the png_strlen(), png_memcpy(), png_memset(), and png_memcmp()
+macros into a private header file (pngpriv.h) that is not accessible to
+applications.
+
+In png_get_iCCP, the type of "profile" was changed from png_charpp
+to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep.
+
+There are changes of form in png.h, including new and changed macros to
+declare parts of the API.  Some API functions with arguments that are
+pointers to data not modified within the function have been corrected to
+declare these arguments with const.
+
+Much of the internal use of C macros to control the library build has also
+changed and some of this is visible in the exported header files, in
+particular the use of macros to control data and API elements visible
+during application compilation may require significant revision to
+application code.  (It is extremely rare for an application to do this.)
+
+Any program that compiled against libpng 1.4 and did not use deprecated
+features or access internal library structures should compile and work
+against libpng 1.5, except for the change in the prototype for
+png_get_iCCP() and png_set_iCCP() API functions mentioned above.
+
+libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of
+interlaced images.  The macros return the number of rows and columns in
+each pass and information that can be used to de-interlace and (if
+absolutely necessary) interlace an image.
+
+libpng 1.5.0 adds an API png_longjmp(png_ptr, value).  This API calls
+the application-provided png_longjmp_ptr on the internal, but application
+initialized, longjmp buffer.  It is provided as a convenience to avoid
+the need to use the png_jmpbuf macro, which had the unnecessary side
+effect of resetting the internal png_longjmp_ptr value.
+
+libpng 1.5.0 includes a complete fixed point API.  By default this is
+present along with the corresponding floating point API.  In general the
+fixed point API is faster and smaller than the floating point one because
+the PNG file format used fixed point, not floating point.  This applies
+even if the library uses floating point in internal calculations.  A new
+macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library
+uses floating point arithmetic (the default) or fixed point arithmetic
+internally for performance critical calculations such as gamma correction.
+In some cases, the gamma calculations may produce slightly different
+results.  This has changed the results in png_rgb_to_gray and in alpha
+composition (png_set_background for example). This applies even if the
+original image was already linear (gamma == 1.0) and, therefore, it is
+not necessary to linearize the image.  This is because libpng has *not*
+been changed to optimize that case correctly, yet.
+
+Fixed point support for the sCAL chunk comes with an important caveat;
+the sCAL specification uses a decimal encoding of floating point values
+and the accuracy of PNG fixed point values is insufficient for
+representation of these values. Consequently a "string" API
+(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
+arbitrary sCAL chunks in the absence of either the floating point API or
+internal floating point calculations.  Starting with libpng-1.5.0, both
+of these functions are present when PNG_sCAL_SUPPORTED is defined.  Prior
+to libpng-1.5.0, their presence also depended upon PNG_FIXED_POINT_SUPPORTED
+being defined and PNG_FLOATING_POINT_SUPPORTED not being defined.
+
+Applications no longer need to include the optional distribution header
+file pngusr.h or define the corresponding macros during application
+build in order to see the correct variant of the libpng API.  From 1.5.0
+application code can check for the corresponding _SUPPORTED macro:
+
+#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
+   /* code that uses the inch conversion APIs. */
+#endif
+
+This macro will only be defined if the inch conversion functions have been
+compiled into libpng.  The full set of macros, and whether or not support
+has been compiled in, are available in the header file pnglibconf.h.
+This header file is specific to the libpng build.  Notice that prior to
+1.5.0 the _SUPPORTED macros would always have the default definition unless
+reset by pngusr.h or by explicit settings on the compiler command line.
+These settings may produce compiler warnings or errors in 1.5.0 because
+of macro redefinition.
+
+Applications can now choose whether to use these macros or to call the
+corresponding function by defining PNG_USE_READ_MACROS or
+PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
+only supported from 1.5.0; defining PNG_NO_USE_READ_MACROS prior to 1.5.0
+will lead to a link failure.
+
+Prior to libpng-1.5.4, the zlib compressor used the same set of parameters
+when compressing the IDAT data and textual data such as zTXt and iCCP.
+In libpng-1.5.4 we reinitialized the zlib stream for each type of data.
+We added five png_set_text_*() functions for setting the parameters to
+use with textual data.
+
+Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+option was off by default, and slightly inaccurate scaling occurred.
+This option can no longer be turned off, and the choice of accurate
+or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
+API for accurate scaling or the old png_set_strip_16_to_8() API for simple
+chopping.  In libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+macro became PNG_READ_SCALE_16_TO_8_SUPPORTED, and the PNG_READ_16_TO_8
+macro became PNG_READ_STRIP_16_TO_8_SUPPORTED, to enable the two
+png_set_*_16_to_8() functions separately.
+
+Prior to libpng-1.5.4, the png_set_user_limits() function could only be
+used to reduce the width and height limits from the value of
+PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
+that it could be used to override them.  Now this function will reduce or
+increase the limits.
+
+Starting in libpng-1.5.22, default user limits were established. These
+can be overridden by application calls to png_set_user_limits(),
+png_set_user_chunk_cache_max(), and/or png_set_user_malloc_max().
+The limits are now
+                             max possible  default
+   png_user_width_max        0x7fffffff    1,000,000
+   png_user_height_max       0x7fffffff    1,000,000
+   png_user_chunk_cache_max  0 (unlimited) 1000
+   png_user_chunk_malloc_max 0 (unlimited) 8,000,000
+
+The png_set_option() function (and the "options" member of the png struct) was
+added to libpng-1.5.15, with option PNG_ARM_NEON.
+
+The library now supports a complete fixed point implementation and can
+thus be used on systems that have no floating point support or very
+limited or slow support.  Previously gamma correction, an essential part
+of complete PNG support, required reasonably fast floating point.
+
+As part of this the choice of internal implementation has been made
+independent of the choice of fixed versus floating point APIs and all the
+missing fixed point APIs have been implemented.
+
+The exact mechanism used to control attributes of API functions has
+changed, as described in the INSTALL file.
+
+A new test program, pngvalid, is provided in addition to pngtest.
+pngvalid validates the arithmetic accuracy of the gamma correction
+calculations and includes a number of validations of the file format.
+A subset of the full range of tests is run when "make check" is done
+(in the 'configure' build.)  pngvalid also allows total allocated memory
+usage to be evaluated and performs additional memory overwrite validation.
+
+Many changes to individual feature macros have been made. The following
+are the changes most likely to be noticed by library builders who
+configure libpng:
+
+1) All feature macros now have consistent naming:
+
+#define PNG_NO_feature turns the feature off
+#define PNG_feature_SUPPORTED turns the feature on
+
+pnglibconf.h contains one line for each feature macro which is either:
+
+#define PNG_feature_SUPPORTED
+
+if the feature is supported or:
+
+/*#undef PNG_feature_SUPPORTED*/
+
+if it is not.  Library code consistently checks for the 'SUPPORTED' macro.
+It does not, and libpng applications should not, check for the 'NO' macro
+which will not normally be defined even if the feature is not supported.
+The 'NO' macros are only used internally for setting or not setting the
+corresponding 'SUPPORTED' macros.
+
+Compatibility with the old names is provided as follows:
+
+PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED
+
+And the following definitions disable the corresponding feature:
+
+PNG_SETJMP_NOT_SUPPORTED disables SETJMP
+PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS
+PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV
+PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS
+PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS
+PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS
+
+Library builders should remove use of the above, inconsistent, names.
+
+2) Warning and error message formatting was previously conditional on
+the STDIO feature. The library has been changed to use the
+CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled
+the library no longer uses the printf(3) functions, even though the
+default read/write implementations use (FILE) style stdio.h functions.
+
+3) Three feature macros now control the fixed/floating point decisions:
+
+PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs
+
+PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in
+practice these are normally required internally anyway (because the PNG
+file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT
+merely stops the function from being exported.
+
+PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating
+point implementation or the fixed point one.  Typically the fixed point
+implementation is larger and slower than the floating point implementation
+on a system that supports floating point; however, it may be faster on a
+system which lacks floating point hardware and therefore uses a software
+emulation.
+
+4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the
+functions to read and write ints to be disabled independently of
+PNG_USE_READ_MACROS, which allows libpng to be built with the functions
+even though the default is to use the macros - this allows applications
+to choose at app buildtime whether or not to use macros (previously
+impossible because the functions weren't in the default build.)
+
+.SH XII. Changes to Libpng from version 1.5.x to 1.6.x
+
+A "simplified API" has been added (see documentation in png.h and a simple
+example in contrib/examples/pngtopng.c).  The new publicly visible API
+includes the following:
+
+   macros:
+     PNG_FORMAT_*
+     PNG_IMAGE_*
+   structures:
+     png_control
+     png_image
+   read functions
+     png_image_begin_read_from_file()
+     png_image_begin_read_from_stdio()
+     png_image_begin_read_from_memory()
+     png_image_finish_read()
+     png_image_free()
+   write functions
+     png_image_write_to_file()
+     png_image_write_to_memory()
+     png_image_write_to_stdio()
+
+Starting with libpng-1.6.0, you can configure libpng to prefix all exported
+symbols, using the PNG_PREFIX macro.
+
+We no longer include string.h in png.h.  The include statement has been moved
+to pngpriv.h, where it is not accessible by applications.  Applications that
+need access to information in string.h must add an '#include <string.h>'
+directive.  It does not matter whether this is placed prior to or after
+the '#include "png.h"' directive.
+
+The following API are now DEPRECATED:
+   png_info_init_3()
+   png_convert_to_rfc1123() which has been replaced
+     with png_convert_to_rfc1123_buffer()
+   png_malloc_default()
+   png_free_default()
+   png_reset_zstream()
+
+The following have been removed:
+   png_get_io_chunk_name(), which has been replaced
+     with png_get_io_chunk_type().  The new
+     function returns a 32-bit integer instead of
+     a string.
+   The png_sizeof(), png_strlen(), png_memcpy(), png_memcmp(), and
+     png_memset() macros are no longer used in the libpng sources and
+     have been removed.  These had already been made invisible to applications
+     (i.e., defined in the private pngpriv.h header file) since libpng-1.5.0.
+
+The signatures of many exported functions were changed, such that
+   png_structp became png_structrp or png_const_structrp
+   png_infop became png_inforp or png_const_inforp
+where "rp" indicates a "restricted pointer".
+
+Dropped support for 16-bit platforms. The support for FAR/far types has
+been eliminated and the definition of png_alloc_size_t is now controlled
+by a flag so that 'small size_t' systems can select it if necessary.
+
+Error detection in some chunks has improved; in particular the iCCP chunk
+reader now does pretty complete validation of the basic format.  Some bad
+profiles that were previously accepted are now accepted with a warning or
+rejected, depending upon the png_set_benign_errors() setting, in particular
+the very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
+libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
+means of
+
+    #if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && \
+        defined(PNG_SET_OPTION_SUPPORTED)
+       png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE,
+           PNG_OPTION_ON);
+    #endif
+
+It's not a good idea to do this if you are using the "simplified API",
+which needs to be able to recognize sRGB profiles conveyed via the iCCP
+chunk.
+
+The PNG spec requirement that only grayscale profiles may appear in images
+with color type 0 or 4 and that even if the image only contains gray pixels,
+only RGB profiles may appear in images with color type 2, 3, or 6, is now
+enforced.  The sRGB chunk is allowed to appear in images with any color type
+and is interpreted by libpng to convey a one-tracer-curve gray profile or a
+three-tracer-curve RGB profile as appropriate.
+
+Libpng 1.5.x erroneously used /MD for Debug DLL builds; if you used the debug
+builds in your app and you changed your app to use /MD you will need to
+change it back to /MDd for libpng 1.6.x.
+
+Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
+an empty language field or an empty translated keyword.  Both of these
+are allowed by the PNG specification, so these warnings are no longer issued.
+
+The library now issues an error if the application attempts to set a
+transform after it calls png_read_update_info() or if it attempts to call
+both png_read_update_info() and png_start_read_image() or to call either
+of them more than once.
+
+The default condition for benign_errors is now to treat benign errors as
+warnings while reading and as errors while writing.
+
+The library now issues a warning if both background processing and RGB to
+gray are used when gamma correction happens. As with previous versions of
+the library the results are numerically very incorrect in this case.
+
+There are some minor arithmetic changes in some transforms such as
+png_set_background(), that might be detected by certain regression tests.
+
+Unknown chunk handling has been improved internally, without any API change.
+This adds more correct option control of the unknown handling, corrects
+a pre-existing bug where the per-chunk 'keep' setting is ignored, and makes
+it possible to skip IDAT chunks in the sequential reader.
+
+The machine-generated configure files are no longer included in branches
+libpng16 and later of the GIT repository.  They continue to be included
+in the tarball releases, however.
+
+Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT
+stream to set the size of the sliding window for reading instead of using the
+default 32-kbyte sliding window size.  It was discovered that there are
+hundreds of PNG files in the wild that have incorrect CMF bytes that caused
+zlib to issue the "invalid distance too far back" error and reject the file.
+Libpng-1.6.3 and later calculate their own safe CMF from the image dimensions,
+provide a way to revert to the libpng-1.5.x behavior (ignoring the CMF bytes
+and using a 32-kbyte sliding window), by using
+
+    png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW,
+        PNG_OPTION_ON);
+
+and provide a tool (contrib/tools/pngfix) for rewriting a PNG file while
+optimizing the CMF bytes in its IDAT chunk correctly.
+
+Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
+length, which resulted in PNG files that cannot be read beyond the bad iTXt
+chunk.  This error was fixed in libpng-1.6.3, and a tool (called
+contrib/tools/png-fix-itxt) has been added to the libpng distribution.
+
+Starting with libpng-1.6.17, the PNG_SAFE_LIMITS macro was eliminated
+and safe limits are used by default (users who need larger limits
+can still override them at compile time or run time, as described above).
+
+The new limits are
+                                default   spec limit
+   png_user_width_max         1,000,000  2,147,483,647
+   png_user_height_max        1,000,000  2,147,483,647
+   png_user_chunk_cache_max         128  unlimited
+   png_user_chunk_malloc_max  8,000,000  unlimited
+
+Starting with libpng-1.6.18, a PNG_RELEASE_BUILD macro was added, which allows
+library builders to control compilation for an installed system (a release build).
+It can be set for testing debug or beta builds to ensure that they will compile
+when the build type is switched to RC or STABLE. In essence this overrides the
+PNG_LIBPNG_BUILD_BASE_TYPE definition which is not directly user controllable.
+
+Starting with libpng-1.6.19, attempting to set an over-length PLTE chunk
+is an error. Previously this requirement of the PNG specification was not
+enforced, and the palette was always limited to 256 entries. An over-length
+PLTE chunk found in an input PNG is silently truncated.
+
+Starting with libpng-1.6.31, the eXIf chunk is supported. Libpng does not
+attempt to decode the Exif profile; it simply returns a byte array
+containing the profile to the calling application which must do its own
+decoding.
+
+.SH XIII. Detecting libpng
+
+The png_get_io_ptr() function has been present since libpng-0.88, has never
+changed, and is unaffected by conditional compilation macros.  It is the
+best choice for use in configure scripts for detecting the presence of any
+libpng version since 0.88.  In an autoconf "configure.in" you could use
+
+    AC_CHECK_LIB(png, png_get_io_ptr, ...
+
+.SH XV. Source code repository
+
+Since about February 2009, version 1.2.34, libpng has been under "git" source
+control.  The git repository was built from old libpng-x.y.z.tar.gz files
+going back to version 0.70.  You can access the git repository (read only)
+at
+
+    https://github.com/glennrp/libpng or
+    https://git.code.sf.net/p/libpng/code.git
+
+or you can browse it with a web browser at
+
+    https://github.com/glennrp/libpng or
+    https://sourceforge.net/p/libpng/code/ci/libpng16/tree/
+
+Patches can be sent to png-mng-implement at lists.sourceforge.net or
+uploaded to the libpng bug tracker at
+
+    https://libpng.sourceforge.io/
+
+or as a "pull request" to
+
+    https://github.com/glennrp/libpng/pulls
+
+We also accept patches built from the tar or zip distributions, and
+simple verbal descriptions of bug fixes, reported either to the
+SourceForge bug tracker, to the png-mng-implement at lists.sf.net
+mailing list, as github issues.
+
+.SH XV. Coding style
+
+Our coding style is similar to the "Allman" style
+(See https://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
+braces on separate lines:
+
+    if (condition)
+    {
+       action;
+    }
+
+    else if (another condition)
+    {
+       another action;
+    }
+
+The braces can be omitted from simple one-line actions:
+
+    if (condition)
+       return 0;
+
+We use 3-space indentation, except for continued statements which
+are usually indented the same as the first line of the statement
+plus four more spaces.
+
+For macro definitions we use 2-space indentation, always leaving the "#"
+in the first column.
+
+    #ifndef PNG_NO_FEATURE
+    #  ifndef PNG_FEATURE_SUPPORTED
+    #    define PNG_FEATURE_SUPPORTED
+    #  endif
+    #endif
+
+Comments appear with the leading "/*" at the same indentation as
+the statement that follows the comment:
+
+    /* Single-line comment */
+    statement;
+
+    /* This is a multiple-line
+     * comment.
+     */
+    statement;
+
+Very short comments can be placed after the end of the statement
+to which they pertain:
+
+    statement;    /* comment */
+
+We don't use C++ style ("//") comments. We have, however,
+used them in the past in some now-abandoned MMX assembler
+code.
+
+Functions and their curly braces are not indented, and
+exported functions are marked with PNGAPI:
+
+ /* This is a public function that is visible to
+  * application programmers. It does thus-and-so.
+  */
+ void PNGAPI
+ png_exported_function(png_ptr, png_info, foo)
+ {
+    body;
+ }
+
+The return type and decorations are placed on a separate line
+ahead of the function name, as illustrated above.
+
+The prototypes for all exported functions appear in png.h,
+above the comment that says
+
+    /* Maintainer: Put new public prototypes here ... */
+
+We mark all non-exported functions with "/* PRIVATE */"":
+
+ void /* PRIVATE */
+ png_non_exported_function(png_ptr, png_info, foo)
+ {
+    body;
+ }
+
+The prototypes for non-exported functions (except for those in
+pngtest) appear in pngpriv.h above the comment that says
+
+  /* Maintainer: Put new private prototypes here ^ */
+
+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
+We put a space after the "sizeof" operator and we omit the
+optional parentheses around its argument when the argument
+is an expression, not a type name, and we always enclose the
+sizeof operator, with its argument, in parentheses:
+
+  (sizeof (png_uint_32))
+  (sizeof array)
+
+Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
+though it were a function.
+
+Control keywords if, for, while, and switch are always followed by a space
+to distinguish them from function calls, which have no trailing space.
+
+We put a space after each comma and after each semicolon
+in "for" statements, and we put spaces before and after each
+C binary operator and after "for" or "while", and before
+"?".  We don't put a space between a typecast and the expression
+being cast, nor do we put one between a function name and the
+left parenthesis that follows it:
+
+    for (i = 2; i > 0; \-\-i)
+       y[i] = a(x) + (int)b;
+
+We prefer #ifdef and #ifndef to #if defined() and #if !defined()
+when there is only one macro being tested.  We always use parentheses
+with "defined".
+
+We express integer constants that are used as bit masks in hex format,
+with an even number of lower-case hex digits, and to make them unsigned
+(e.g., 0x00U, 0xffU, 0x0100U) and long if they are greater than 0x7fff
+(e.g., 0xffffUL).
+
+We prefer to use underscores rather than camelCase in names, except
+for a few type names that we inherit from zlib.h.
+
+We prefer "if (something != 0)" and "if (something == 0)" over
+"if (something)" and if "(!something)", respectively, and for pointers
+we prefer "if (some_pointer != NULL)" or "if (some_pointer == NULL)".
+
+We do not use the TAB character for indentation in the C sources.
+
+Lines do not exceed 80 characters.
+
+Other rules can be inferred by inspecting the libpng source.
+
+.SH NOTE
+
+Note about libpng version numbers:
+
+Due to various miscommunications, unforeseen code incompatibilities
+and occasional factors outside the authors' control, version numbering
+on the library has not always been consistent and straightforward.
+The following table summarizes matters since version 0.89c, which was
+the first widely used release:
+
+ source               png.h    png.h  shared-lib
+ version              string   int    version
+ -------              ------   -----  ----------
+ 0.89c "1.0 beta 3"     0.89      89  1.0.89
+ 0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
+ 0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
+ 0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
+ 0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
+ 0.97c                  0.97      97  2.0.97
+ 0.98                   0.98      98  2.0.98
+ 0.99                   0.99      98  2.0.99
+ 0.99a-m                0.99      99  2.0.99
+ 1.00                   1.00     100  2.1.0 [100 should be 10000]
+ 1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
+ 1.0.1       png.h string is   10001  2.1.0
+ 1.0.1a-e    identical to the  10002  from here on, the shared library
+ 1.0.2       source version)   10002  is 2.V where V is the source code
+ 1.0.2a-b                      10003  version, except as noted.
+ 1.0.3                         10003
+ 1.0.3a-d                      10004
+ 1.0.4                         10004
+ 1.0.4a-f                      10005
+ 1.0.5 (+ 2 patches)           10005
+ 1.0.5a-d                      10006
+ 1.0.5e-r                      10100 (not source compatible)
+ 1.0.5s-v                      10006 (not binary compatible)
+ 1.0.6 (+ 3 patches)           10006 (still binary incompatible)
+ 1.0.6d-f                      10007 (still binary incompatible)
+ 1.0.6g                        10007
+ 1.0.6h                        10007  10.6h (testing xy.z so-numbering)
+ 1.0.6i                        10007  10.6i
+ 1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
+ 1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
+ 1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
+ 1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
+ 1.0.7                    1    10007  (still compatible)
+ ...
+ 1.0.69                  10    10069  10.so.0.69[.0]
+ ...
+ 1.2.59                  13    10259  12.so.0.59[.0]
+ ...
+ 1.4.20                  14    10420  14.so.0.20[.0]
+ ...
+ 1.5.30                  15    10530  15.so.15.30[.0]
+ ...
+ 1.6.35                  16    10635  16.so.16.35[.0]
+
+Henceforth the source version will match the shared-library minor and
+patch numbers; the shared-library major version number will be used for
+changes in backward compatibility, as it is intended.
+The PNG_PNGLIB_VER macro, which is not used within libpng but is
+available for applications, is an unsigned integer of the form XYYZZ
+corresponding to the source version X.Y.Z (leading zeros in Y and Z).
+Beta versions were given the previous public release number plus a
+letter, until version 1.0.6j; from then on they were given the upcoming
+public release number plus "betaNN" or "rcNN".
+
+.SH "SEE ALSO"
+.IR libpngpf(3) ", " png(5)
+.LP
+.IR libpng :
+.IP
+https://libpng.sourceforge.io/ (follow the [DOWNLOAD] link)
+http://www.libpng.org/pub/png
+
+.LP
+.IR zlib :
+.IP
+(generally) at the same location as
+.I libpng
+or at
+.br
+https://zlib.net/
+
+.LP
+.IR PNG specification: RFC 2083
+.IP
+(generally) at the same location as
+.I libpng
+or at
+.br
+https://www.ietf.org/rfc/rfc2083.txt
+.br
+or (as a W3C Recommendation) at
+.br
+https://www.w3.org/TR/REC-png.html
+
+.LP
+In the case of any inconsistency between the PNG specification
+and this library, the specification takes precedence.
+
+.SH AUTHORS
+This man page:
+Initially created by Glenn Randers-Pehrson.
+Maintained by Cosmin Truta.
+
+The contributing authors would like to thank all those who helped
+with testing, bug fixes, and patience.  This wouldn't have been
+possible without all of you.
+
+Thanks to Frank J. T. Wojcik for helping with the documentation.
+
+Libpng:
+Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
+Maintained by Cosmin Truta.
+
+Supported by the PNG development group
+.br
+png-mng-implement at lists.sourceforge.net (subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe).
+
+.\" end of man page
diff --git a/extern/libpng/libpng.pc.in b/extern/libpng/libpng.pc.in
new file mode 100644
index 0000000000..9708e9af2b
--- /dev/null
+++ b/extern/libpng/libpng.pc.in
@@ -0,0 +1,12 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+
+Name: libpng
+Description: Loads and saves PNG files
+Version: @PNGLIB_VERSION@
+Requires: zlib
+Libs: -L${libdir} -lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+Libs.private: @LIBS@
+Cflags: -I${includedir}
diff --git a/extern/libpng/libpngpf.3 b/extern/libpng/libpngpf.3
new file mode 100644
index 0000000000..6909c70a3d
--- /dev/null
+++ b/extern/libpng/libpngpf.3
@@ -0,0 +1,24 @@
+.TH LIBPNGPF 3 "April 14, 2019"
+.SH NAME
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.37
+(private functions)
+
+.SH SYNOPSIS
+\fB#include \fI"pngpriv.h"
+
+\fBAs of libpng version \fP\fI1.5.1\fP\fB, this section is no longer
+\fP\fImaintained\fP\fB, now that the private function prototypes are hidden in
+\fP\fIpngpriv.h\fP\fB and not accessible to applications. Look in
+\fP\fIpngpriv.h\fP\fB for the prototypes and a short description of each
+function.
+
+.SH DESCRIPTION
+The functions previously listed here are used privately by libpng and are not
+available for use by applications.  They are not "exported" to applications
+using shared libraries.
+
+.SH "SEE ALSO"
+.BR "png"(5), " libpng"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
+
+.SH AUTHORS
+Cosmin Truta, Glenn Randers-Pehrson
diff --git a/extern/libpng/ltmain.sh b/extern/libpng/ltmain.sh
new file mode 100755
index 0000000000..0f0a2da3f9
--- /dev/null
+++ b/extern/libpng/ltmain.sh
@@ -0,0 +1,11147 @@
+#! /bin/sh
+## DO NOT EDIT - This file generated from ./build-aux/ltmain.in
+##               by inline-source v2014-01-03.01
+
+# libtool (GNU libtool) 2.4.6
+# Provide generalized library-building support services.
+# Written by Gordon Matzigkeit <gord@gnu.ai.mit.edu>, 1996
+
+# Copyright (C) 1996-2015 Free Software Foundation, Inc.
+# This is free software; see the source for copying conditions.  There is NO
+# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+# GNU Libtool is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# As a special exception to the GNU General Public License,
+# if you distribute this file as part of a program or library that
+# is built using GNU Libtool, you may include this file under the
+# same distribution terms that you use for the rest of that program.
+#
+# GNU Libtool is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+PROGRAM=libtool
+PACKAGE=libtool
+VERSION=2.4.6
+package_revision=2.4.6
+
+
+## ------ ##
+## Usage. ##
+## ------ ##
+
+# Run './libtool --help' for help with using this script from the
+# command line.
+
+
+## ------------------------------- ##
+## User overridable command paths. ##
+## ------------------------------- ##
+
+# After configure completes, it has a better idea of some of the
+# shell tools we need than the defaults used by the functions shared
+# with bootstrap, so set those here where they can still be over-
+# ridden by the user, but otherwise take precedence.
+
+: ${AUTOCONF="autoconf"}
+: ${AUTOMAKE="automake"}
+
+
+## -------------------------- ##
+## Source external libraries. ##
+## -------------------------- ##
+
+# Much of our low-level functionality needs to be sourced from external
+# libraries, which are installed to $pkgauxdir.
+
+# Set a version string for this script.
+scriptversion=2015-01-20.17; # UTC
+
+# General shell script boiler plate, and helper functions.
+# Written by Gary V. Vaughan, 2004
+
+# Copyright (C) 2004-2015 Free Software Foundation, Inc.
+# This is free software; see the source for copying conditions.  There is NO
+# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+
+# As a special exception to the GNU General Public License, if you distribute
+# this file as part of a program or library that is built using GNU Libtool,
+# you may include this file under the same distribution terms that you use
+# for the rest of that program.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNES FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# Please report bugs or propose patches to gary@gnu.org.
+
+
+## ------ ##
+## Usage. ##
+## ------ ##
+
+# Evaluate this file near the top of your script to gain access to
+# the functions and variables defined here:
+#
+#   . `echo "$0" | ${SED-sed} 's|[^/]*$||'`/build-aux/funclib.sh
+#
+# If you need to override any of the default environment variable
+# settings, do that before evaluating this file.
+
+
+## -------------------- ##
+## Shell normalisation. ##
+## -------------------- ##
+
+# Some shells need a little help to be as Bourne compatible as possible.
+# Before doing anything else, make sure all that help has been provided!
+
+DUALCASE=1; export DUALCASE # for MKS sh
+if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else
+  case `(set -o) 2>/dev/null` in *posix*) set -o posix ;; esac
+fi
+
+# NLS nuisances: We save the old values in case they are required later.
+_G_user_locale=
+_G_safe_locale=
+for _G_var in LANG LANGUAGE LC_ALL LC_CTYPE LC_COLLATE LC_MESSAGES
+do
+  eval "if test set = \"\${$_G_var+set}\"; then
+          save_$_G_var=\$$_G_var
+          $_G_var=C
+	  export $_G_var
+	  _G_user_locale=\"$_G_var=\\\$save_\$_G_var; \$_G_user_locale\"
+	  _G_safe_locale=\"$_G_var=C; \$_G_safe_locale\"
+	fi"
+done
+
+# CDPATH.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+# Make sure IFS has a sensible default
+sp=' '
+nl='
+'
+IFS="$sp	$nl"
+
+# There are apparently some retarded systems that use ';' as a PATH separator!
+if test "${PATH_SEPARATOR+set}" != set; then
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
+    (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
+      PATH_SEPARATOR=';'
+  }
+fi
+
+
+
+## ------------------------- ##
+## Locate command utilities. ##
+## ------------------------- ##
+
+
+# func_executable_p FILE
+# ----------------------
+# Check that FILE is an executable regular file.
+func_executable_p ()
+{
+    test -f "$1" && test -x "$1"
+}
+
+
+# func_path_progs PROGS_LIST CHECK_FUNC [PATH]
+# --------------------------------------------
+# Search for either a program that responds to --version with output
+# containing "GNU", or else returned by CHECK_FUNC otherwise, by
+# trying all the directories in PATH with each of the elements of
+# PROGS_LIST.
+#
+# CHECK_FUNC should accept the path to a candidate program, and
+# set $func_check_prog_result if it truncates its output less than
+# $_G_path_prog_max characters.
+func_path_progs ()
+{
+    _G_progs_list=$1
+    _G_check_func=$2
+    _G_PATH=${3-"$PATH"}
+
+    _G_path_prog_max=0
+    _G_path_prog_found=false
+    _G_save_IFS=$IFS; IFS=${PATH_SEPARATOR-:}
+    for _G_dir in $_G_PATH; do
+      IFS=$_G_save_IFS
+      test -z "$_G_dir" && _G_dir=.
+      for _G_prog_name in $_G_progs_list; do
+        for _exeext in '' .EXE; do
+          _G_path_prog=$_G_dir/$_G_prog_name$_exeext
+          func_executable_p "$_G_path_prog" || continue
+          case `"$_G_path_prog" --version 2>&1` in
+            *GNU*) func_path_progs_result=$_G_path_prog _G_path_prog_found=: ;;
+            *)     $_G_check_func $_G_path_prog
+		   func_path_progs_result=$func_check_prog_result
+		   ;;
+          esac
+          $_G_path_prog_found && break 3
+        done
+      done
+    done
+    IFS=$_G_save_IFS
+    test -z "$func_path_progs_result" && {
+      echo "no acceptable sed could be found in \$PATH" >&2
+      exit 1
+    }
+}
+
+
+# We want to be able to use the functions in this file before configure
+# has figured out where the best binaries are kept, which means we have
+# to search for them ourselves - except when the results are already set
+# where we skip the searches.
+
+# Unless the user overrides by setting SED, search the path for either GNU
+# sed, or the sed that truncates its output the least.
+test -z "$SED" && {
+  _G_sed_script=s/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb/
+  for _G_i in 1 2 3 4 5 6 7; do
+    _G_sed_script=$_G_sed_script$nl$_G_sed_script
+  done
+  echo "$_G_sed_script" 2>/dev/null | sed 99q >conftest.sed
+  _G_sed_script=
+
+  func_check_prog_sed ()
+  {
+    _G_path_prog=$1
+
+    _G_count=0
+    printf 0123456789 >conftest.in
+    while :
+    do
+      cat conftest.in conftest.in >conftest.tmp
+      mv conftest.tmp conftest.in
+      cp conftest.in conftest.nl
+      echo '' >> conftest.nl
+      "$_G_path_prog" -f conftest.sed <conftest.nl >conftest.out 2>/dev/null || break
+      diff conftest.out conftest.nl >/dev/null 2>&1 || break
+      _G_count=`expr $_G_count + 1`
+      if test "$_G_count" -gt "$_G_path_prog_max"; then
+        # Best one so far, save it but keep looking for a better one
+        func_check_prog_result=$_G_path_prog
+        _G_path_prog_max=$_G_count
+      fi
+      # 10*(2^10) chars as input seems more than enough
+      test 10 -lt "$_G_count" && break
+    done
+    rm -f conftest.in conftest.tmp conftest.nl conftest.out
+  }
+
+  func_path_progs "sed gsed" func_check_prog_sed $PATH:/usr/xpg4/bin
+  rm -f conftest.sed
+  SED=$func_path_progs_result
+}
+
+
+# Unless the user overrides by setting GREP, search the path for either GNU
+# grep, or the grep that truncates its output the least.
+test -z "$GREP" && {
+  func_check_prog_grep ()
+  {
+    _G_path_prog=$1
+
+    _G_count=0
+    _G_path_prog_max=0
+    printf 0123456789 >conftest.in
+    while :
+    do
+      cat conftest.in conftest.in >conftest.tmp
+      mv conftest.tmp conftest.in
+      cp conftest.in conftest.nl
+      echo 'GREP' >> conftest.nl
+      "$_G_path_prog" -e 'GREP$' -e '-(cannot match)-' <conftest.nl >conftest.out 2>/dev/null || break
+      diff conftest.out conftest.nl >/dev/null 2>&1 || break
+      _G_count=`expr $_G_count + 1`
+      if test "$_G_count" -gt "$_G_path_prog_max"; then
+        # Best one so far, save it but keep looking for a better one
+        func_check_prog_result=$_G_path_prog
+        _G_path_prog_max=$_G_count
+      fi
+      # 10*(2^10) chars as input seems more than enough
+      test 10 -lt "$_G_count" && break
+    done
+    rm -f conftest.in conftest.tmp conftest.nl conftest.out
+  }
+
+  func_path_progs "grep ggrep" func_check_prog_grep $PATH:/usr/xpg4/bin
+  GREP=$func_path_progs_result
+}
+
+
+## ------------------------------- ##
+## User overridable command paths. ##
+## ------------------------------- ##
+
+# All uppercase variable names are used for environment variables.  These
+# variables can be overridden by the user before calling a script that
+# uses them if a suitable command of that name is not already available
+# in the command search PATH.
+
+: ${CP="cp -f"}
+: ${ECHO="printf %s\n"}
+: ${EGREP="$GREP -E"}
+: ${FGREP="$GREP -F"}
+: ${LN_S="ln -s"}
+: ${MAKE="make"}
+: ${MKDIR="mkdir"}
+: ${MV="mv -f"}
+: ${RM="rm -f"}
+: ${SHELL="${CONFIG_SHELL-/bin/sh}"}
+
+
+## -------------------- ##
+## Useful sed snippets. ##
+## -------------------- ##
+
+sed_dirname='s|/[^/]*$||'
+sed_basename='s|^.*/||'
+
+# Sed substitution that helps us do robust quoting.  It backslashifies
+# metacharacters that are still active within double-quoted strings.
+sed_quote_subst='s|\([`"$\\]\)|\\\1|g'
+
+# Same as above, but do not quote variable references.
+sed_double_quote_subst='s/\(["`\\]\)/\\\1/g'
+
+# Sed substitution that turns a string into a regex matching for the
+# string literally.
+sed_make_literal_regex='s|[].[^$\\*\/]|\\&|g'
+
+# Sed substitution that converts a w32 file name or path
+# that contains forward slashes, into one that contains
+# (escaped) backslashes.  A very naive implementation.
+sed_naive_backslashify='s|\\\\*|\\|g;s|/|\\|g;s|\\|\\\\|g'
+
+# Re-'\' parameter expansions in output of sed_double_quote_subst that
+# were '\'-ed in input to the same.  If an odd number of '\' preceded a
+# '$' in input to sed_double_quote_subst, that '$' was protected from
+# expansion.  Since each input '\' is now two '\'s, look for any number
+# of runs of four '\'s followed by two '\'s and then a '$'.  '\' that '$'.
+_G_bs='\\'
+_G_bs2='\\\\'
+_G_bs4='\\\\\\\\'
+_G_dollar='\$'
+sed_double_backslash="\
+  s/$_G_bs4/&\\
+/g
+  s/^$_G_bs2$_G_dollar/$_G_bs&/
+  s/\\([^$_G_bs]\\)$_G_bs2$_G_dollar/\\1$_G_bs2$_G_bs$_G_dollar/g
+  s/\n//g"
+
+
+## ----------------- ##
+## Global variables. ##
+## ----------------- ##
+
+# Except for the global variables explicitly listed below, the following
+# functions in the '^func_' namespace, and the '^require_' namespace
+# variables initialised in the 'Resource management' section, sourcing
+# this file will not pollute your global namespace with anything
+# else. There's no portable way to scope variables in Bourne shell
+# though, so actually running these functions will sometimes place
+# results into a variable named after the function, and often use
+# temporary variables in the '^_G_' namespace. If you are careful to
+# avoid using those namespaces casually in your sourcing script, things
+# should continue to work as you expect. And, of course, you can freely
+# overwrite any of the functions or variables defined here before
+# calling anything to customize them.
+
+EXIT_SUCCESS=0
+EXIT_FAILURE=1
+EXIT_MISMATCH=63  # $? = 63 is used to indicate version mismatch to missing.
+EXIT_SKIP=77	  # $? = 77 is used to indicate a skipped test to automake.
+
+# Allow overriding, eg assuming that you follow the convention of
+# putting '$debug_cmd' at the start of all your functions, you can get
+# bash to show function call trace with:
+#
+#    debug_cmd='eval echo "${FUNCNAME[0]} $*" >&2' bash your-script-name
+debug_cmd=${debug_cmd-":"}
+exit_cmd=:
+
+# By convention, finish your script with:
+#
+#    exit $exit_status
+#
+# so that you can set exit_status to non-zero if you want to indicate
+# something went wrong during execution without actually bailing out at
+# the point of failure.
+exit_status=$EXIT_SUCCESS
+
+# Work around backward compatibility issue on IRIX 6.5. On IRIX 6.4+, sh
+# is ksh but when the shell is invoked as "sh" and the current value of
+# the _XPG environment variable is not equal to 1 (one), the special
+# positional parameter $0, within a function call, is the name of the
+# function.
+progpath=$0
+
+# The name of this program.
+progname=`$ECHO "$progpath" |$SED "$sed_basename"`
+
+# Make sure we have an absolute progpath for reexecution:
+case $progpath in
+  [\\/]*|[A-Za-z]:\\*) ;;
+  *[\\/]*)
+     progdir=`$ECHO "$progpath" |$SED "$sed_dirname"`
+     progdir=`cd "$progdir" && pwd`
+     progpath=$progdir/$progname
+     ;;
+  *)
+     _G_IFS=$IFS
+     IFS=${PATH_SEPARATOR-:}
+     for progdir in $PATH; do
+       IFS=$_G_IFS
+       test -x "$progdir/$progname" && break
+     done
+     IFS=$_G_IFS
+     test -n "$progdir" || progdir=`pwd`
+     progpath=$progdir/$progname
+     ;;
+esac
+
+
+## ----------------- ##
+## Standard options. ##
+## ----------------- ##
+
+# The following options affect the operation of the functions defined
+# below, and should be set appropriately depending on run-time para-
+# meters passed on the command line.
+
+opt_dry_run=false
+opt_quiet=false
+opt_verbose=false
+
+# Categories 'all' and 'none' are always available.  Append any others
+# you will pass as the first argument to func_warning from your own
+# code.
+warning_categories=
+
+# By default, display warnings according to 'opt_warning_types'.  Set
+# 'warning_func'  to ':' to elide all warnings, or func_fatal_error to
+# treat the next displayed warning as a fatal error.
+warning_func=func_warn_and_continue
+
+# Set to 'all' to display all warnings, 'none' to suppress all
+# warnings, or a space delimited list of some subset of
+# 'warning_categories' to display only the listed warnings.
+opt_warning_types=all
+
+
+## -------------------- ##
+## Resource management. ##
+## -------------------- ##
+
+# This section contains definitions for functions that each ensure a
+# particular resource (a file, or a non-empty configuration variable for
+# example) is available, and if appropriate to extract default values
+# from pertinent package files. Call them using their associated
+# 'require_*' variable to ensure that they are executed, at most, once.
+#
+# It's entirely deliberate that calling these functions can set
+# variables that don't obey the namespace limitations obeyed by the rest
+# of this file, in order that that they be as useful as possible to
+# callers.
+
+
+# require_term_colors
+# -------------------
+# Allow display of bold text on terminals that support it.
+require_term_colors=func_require_term_colors
+func_require_term_colors ()
+{
+    $debug_cmd
+
+    test -t 1 && {
+      # COLORTERM and USE_ANSI_COLORS environment variables take
+      # precedence, because most terminfo databases neglect to describe
+      # whether color sequences are supported.
+      test -n "${COLORTERM+set}" && : ${USE_ANSI_COLORS="1"}
+
+      if test 1 = "$USE_ANSI_COLORS"; then
+        # Standard ANSI escape sequences
+        tc_reset=''
+        tc_bold='';   tc_standout=''
+        tc_red='';   tc_green=''
+        tc_blue='';  tc_cyan=''
+      else
+        # Otherwise trust the terminfo database after all.
+        test -n "`tput sgr0 2>/dev/null`" && {
+          tc_reset=`tput sgr0`
+          test -n "`tput bold 2>/dev/null`" && tc_bold=`tput bold`
+          tc_standout=$tc_bold
+          test -n "`tput smso 2>/dev/null`" && tc_standout=`tput smso`
+          test -n "`tput setaf 1 2>/dev/null`" && tc_red=`tput setaf 1`
+          test -n "`tput setaf 2 2>/dev/null`" && tc_green=`tput setaf 2`
+          test -n "`tput setaf 4 2>/dev/null`" && tc_blue=`tput setaf 4`
+          test -n "`tput setaf 5 2>/dev/null`" && tc_cyan=`tput setaf 5`
+        }
+      fi
+    }
+
+    require_term_colors=:
+}
+
+
+## ----------------- ##
+## Function library. ##
+## ----------------- ##
+
+# This section contains a variety of useful functions to call in your
+# scripts. Take note of the portable wrappers for features provided by
+# some modern shells, which will fall back to slower equivalents on
+# less featureful shells.
+
+
+# func_append VAR VALUE
+# ---------------------
+# Append VALUE onto the existing contents of VAR.
+
+  # We should try to minimise forks, especially on Windows where they are
+  # unreasonably slow, so skip the feature probes when bash or zsh are
+  # being used:
+  if test set = "${BASH_VERSION+set}${ZSH_VERSION+set}"; then
+    : ${_G_HAVE_ARITH_OP="yes"}
+    : ${_G_HAVE_XSI_OPS="yes"}
+    # The += operator was introduced in bash 3.1
+    case $BASH_VERSION in
+      [12].* | 3.0 | 3.0*) ;;
+      *)
+        : ${_G_HAVE_PLUSEQ_OP="yes"}
+        ;;
+    esac
+  fi
+
+  # _G_HAVE_PLUSEQ_OP
+  # Can be empty, in which case the shell is probed, "yes" if += is
+  # useable or anything else if it does not work.
+  test -z "$_G_HAVE_PLUSEQ_OP" \
+    && (eval 'x=a; x+=" b"; test "a b" = "$x"') 2>/dev/null \
+    && _G_HAVE_PLUSEQ_OP=yes
+
+if test yes = "$_G_HAVE_PLUSEQ_OP"
+then
+  # This is an XSI compatible shell, allowing a faster implementation...
+  eval 'func_append ()
+  {
+    $debug_cmd
+
+    eval "$1+=\$2"
+  }'
+else
+  # ...otherwise fall back to using expr, which is often a shell builtin.
+  func_append ()
+  {
+    $debug_cmd
+
+    eval "$1=\$$1\$2"
+  }
+fi
+
+
+# func_append_quoted VAR VALUE
+# ----------------------------
+# Quote VALUE and append to the end of shell variable VAR, separated
+# by a space.
+if test yes = "$_G_HAVE_PLUSEQ_OP"; then
+  eval 'func_append_quoted ()
+  {
+    $debug_cmd
+
+    func_quote_for_eval "$2"
+    eval "$1+=\\ \$func_quote_for_eval_result"
+  }'
+else
+  func_append_quoted ()
+  {
+    $debug_cmd
+
+    func_quote_for_eval "$2"
+    eval "$1=\$$1\\ \$func_quote_for_eval_result"
+  }
+fi
+
+
+# func_append_uniq VAR VALUE
+# --------------------------
+# Append unique VALUE onto the existing contents of VAR, assuming
+# entries are delimited by the first character of VALUE.  For example:
+#
+#   func_append_uniq options " --another-option option-argument"
+#
+# will only append to $options if " --another-option option-argument "
+# is not already present somewhere in $options already (note spaces at
+# each end implied by leading space in second argument).
+func_append_uniq ()
+{
+    $debug_cmd
+
+    eval _G_current_value='`$ECHO $'$1'`'
+    _G_delim=`expr "$2" : '\(.\)'`
+
+    case $_G_delim$_G_current_value$_G_delim in
+      *"$2$_G_delim"*) ;;
+      *) func_append "$@" ;;
+    esac
+}
+
+
+# func_arith TERM...
+# ------------------
+# Set func_arith_result to the result of evaluating TERMs.
+  test -z "$_G_HAVE_ARITH_OP" \
+    && (eval 'test 2 = $(( 1 + 1 ))') 2>/dev/null \
+    && _G_HAVE_ARITH_OP=yes
+
+if test yes = "$_G_HAVE_ARITH_OP"; then
+  eval 'func_arith ()
+  {
+    $debug_cmd
+
+    func_arith_result=$(( $* ))
+  }'
+else
+  func_arith ()
+  {
+    $debug_cmd
+
+    func_arith_result=`expr "$@"`
+  }
+fi
+
+
+# func_basename FILE
+# ------------------
+# Set func_basename_result to FILE with everything up to and including
+# the last / stripped.
+if test yes = "$_G_HAVE_XSI_OPS"; then
+  # If this shell supports suffix pattern removal, then use it to avoid
+  # forking. Hide the definitions single quotes in case the shell chokes
+  # on unsupported syntax...
+  _b='func_basename_result=${1##*/}'
+  _d='case $1 in
+        */*) func_dirname_result=${1%/*}$2 ;;
+        *  ) func_dirname_result=$3        ;;
+      esac'
+
+else
+  # ...otherwise fall back to using sed.
+  _b='func_basename_result=`$ECHO "$1" |$SED "$sed_basename"`'
+  _d='func_dirname_result=`$ECHO "$1"  |$SED "$sed_dirname"`
+      if test "X$func_dirname_result" = "X$1"; then
+        func_dirname_result=$3
+      else
+        func_append func_dirname_result "$2"
+      fi'
+fi
+
+eval 'func_basename ()
+{
+    $debug_cmd
+
+    '"$_b"'
+}'
+
+
+# func_dirname FILE APPEND NONDIR_REPLACEMENT
+# -------------------------------------------
+# Compute the dirname of FILE.  If nonempty, add APPEND to the result,
+# otherwise set result to NONDIR_REPLACEMENT.
+eval 'func_dirname ()
+{
+    $debug_cmd
+
+    '"$_d"'
+}'
+
+
+# func_dirname_and_basename FILE APPEND NONDIR_REPLACEMENT
+# --------------------------------------------------------
+# Perform func_basename and func_dirname in a single function
+# call:
+#   dirname:  Compute the dirname of FILE.  If nonempty,
+#             add APPEND to the result, otherwise set result
+#             to NONDIR_REPLACEMENT.
+#             value returned in "$func_dirname_result"
+#   basename: Compute filename of FILE.
+#             value retuned in "$func_basename_result"
+# For efficiency, we do not delegate to the functions above but instead
+# duplicate the functionality here.
+eval 'func_dirname_and_basename ()
+{
+    $debug_cmd
+
+    '"$_b"'
+    '"$_d"'
+}'
+
+
+# func_echo ARG...
+# ----------------
+# Echo program name prefixed message.
+func_echo ()
+{
+    $debug_cmd
+
+    _G_message=$*
+
+    func_echo_IFS=$IFS
+    IFS=$nl
+    for _G_line in $_G_message; do
+      IFS=$func_echo_IFS
+      $ECHO "$progname: $_G_line"
+    done
+    IFS=$func_echo_IFS
+}
+
+
+# func_echo_all ARG...
+# --------------------
+# Invoke $ECHO with all args, space-separated.
+func_echo_all ()
+{
+    $ECHO "$*"
+}
+
+
+# func_echo_infix_1 INFIX ARG...
+# ------------------------------
+# Echo program name, followed by INFIX on the first line, with any
+# additional lines not showing INFIX.
+func_echo_infix_1 ()
+{
+    $debug_cmd
+
+    $require_term_colors
+
+    _G_infix=$1; shift
+    _G_indent=$_G_infix
+    _G_prefix="$progname: $_G_infix: "
+    _G_message=$*
+
+    # Strip color escape sequences before counting printable length
+    for _G_tc in "$tc_reset" "$tc_bold" "$tc_standout" "$tc_red" "$tc_green" "$tc_blue" "$tc_cyan"
+    do
+      test -n "$_G_tc" && {
+        _G_esc_tc=`$ECHO "$_G_tc" | $SED "$sed_make_literal_regex"`
+        _G_indent=`$ECHO "$_G_indent" | $SED "s|$_G_esc_tc||g"`
+      }
+    done
+    _G_indent="$progname: "`echo "$_G_indent" | $SED 's|.| |g'`"  " ## exclude from sc_prohibit_nested_quotes
+
+    func_echo_infix_1_IFS=$IFS
+    IFS=$nl
+    for _G_line in $_G_message; do
+      IFS=$func_echo_infix_1_IFS
+      $ECHO "$_G_prefix$tc_bold$_G_line$tc_reset" >&2
+      _G_prefix=$_G_indent
+    done
+    IFS=$func_echo_infix_1_IFS
+}
+
+
+# func_error ARG...
+# -----------------
+# Echo program name prefixed message to standard error.
+func_error ()
+{
+    $debug_cmd
+
+    $require_term_colors
+
+    func_echo_infix_1 "  $tc_standout${tc_red}error$tc_reset" "$*" >&2
+}
+
+
+# func_fatal_error ARG...
+# -----------------------
+# Echo program name prefixed message to standard error, and exit.
+func_fatal_error ()
+{
+    $debug_cmd
+
+    func_error "$*"
+    exit $EXIT_FAILURE
+}
+
+
+# func_grep EXPRESSION FILENAME
+# -----------------------------
+# Check whether EXPRESSION matches any line of FILENAME, without output.
+func_grep ()
+{
+    $debug_cmd
+
+    $GREP "$1" "$2" >/dev/null 2>&1
+}
+
+
+# func_len STRING
+# ---------------
+# Set func_len_result to the length of STRING. STRING may not
+# start with a hyphen.
+  test -z "$_G_HAVE_XSI_OPS" \
+    && (eval 'x=a/b/c;
+      test 5aa/bb/cc = "${#x}${x%%/*}${x%/*}${x#*/}${x##*/}"') 2>/dev/null \
+    && _G_HAVE_XSI_OPS=yes
+
+if test yes = "$_G_HAVE_XSI_OPS"; then
+  eval 'func_len ()
+  {
+    $debug_cmd
+
+    func_len_result=${#1}
+  }'
+else
+  func_len ()
+  {
+    $debug_cmd
+
+    func_len_result=`expr "$1" : ".*" 2>/dev/null || echo $max_cmd_len`
+  }
+fi
+
+
+# func_mkdir_p DIRECTORY-PATH
+# ---------------------------
+# Make sure the entire path to DIRECTORY-PATH is available.
+func_mkdir_p ()
+{
+    $debug_cmd
+
+    _G_directory_path=$1
+    _G_dir_list=
+
+    if test -n "$_G_directory_path" && test : != "$opt_dry_run"; then
+
+      # Protect directory names starting with '-'
+      case $_G_directory_path in
+        -*) _G_directory_path=./$_G_directory_path ;;
+      esac
+
+      # While some portion of DIR does not yet exist...
+      while test ! -d "$_G_directory_path"; do
+        # ...make a list in topmost first order.  Use a colon delimited
+	# list incase some portion of path contains whitespace.
+        _G_dir_list=$_G_directory_path:$_G_dir_list
+
+        # If the last portion added has no slash in it, the list is done
+        case $_G_directory_path in */*) ;; *) break ;; esac
+
+        # ...otherwise throw away the child directory and loop
+        _G_directory_path=`$ECHO "$_G_directory_path" | $SED -e "$sed_dirname"`
+      done
+      _G_dir_list=`$ECHO "$_G_dir_list" | $SED 's|:*$||'`
+
+      func_mkdir_p_IFS=$IFS; IFS=:
+      for _G_dir in $_G_dir_list; do
+	IFS=$func_mkdir_p_IFS
+        # mkdir can fail with a 'File exist' error if two processes
+        # try to create one of the directories concurrently.  Don't
+        # stop in that case!
+        $MKDIR "$_G_dir" 2>/dev/null || :
+      done
+      IFS=$func_mkdir_p_IFS
+
+      # Bail out if we (or some other process) failed to create a directory.
+      test -d "$_G_directory_path" || \
+        func_fatal_error "Failed to create '$1'"
+    fi
+}
+
+
+# func_mktempdir [BASENAME]
+# -------------------------
+# Make a temporary directory that won't clash with other running
+# libtool processes, and avoids race conditions if possible.  If
+# given, BASENAME is the basename for that directory.
+func_mktempdir ()
+{
+    $debug_cmd
+
+    _G_template=${TMPDIR-/tmp}/${1-$progname}
+
+    if test : = "$opt_dry_run"; then
+      # Return a directory name, but don't create it in dry-run mode
+      _G_tmpdir=$_G_template-$$
+    else
+
+      # If mktemp works, use that first and foremost
+      _G_tmpdir=`mktemp -d "$_G_template-XXXXXXXX" 2>/dev/null`
+
+      if test ! -d "$_G_tmpdir"; then
+        # Failing that, at least try and use $RANDOM to avoid a race
+        _G_tmpdir=$_G_template-${RANDOM-0}$$
+
+        func_mktempdir_umask=`umask`
+        umask 0077
+        $MKDIR "$_G_tmpdir"
+        umask $func_mktempdir_umask
+      fi
+
+      # If we're not in dry-run mode, bomb out on failure
+      test -d "$_G_tmpdir" || \
+        func_fatal_error "cannot create temporary directory '$_G_tmpdir'"
+    fi
+
+    $ECHO "$_G_tmpdir"
+}
+
+
+# func_normal_abspath PATH
+# ------------------------
+# Remove doubled-up and trailing slashes, "." path components,
+# and cancel out any ".." path components in PATH after making
+# it an absolute path.
+func_normal_abspath ()
+{
+    $debug_cmd
+
+    # These SED scripts presuppose an absolute path with a trailing slash.
+    _G_pathcar='s|^/\([^/]*\).*$|\1|'
+    _G_pathcdr='s|^/[^/]*||'
+    _G_removedotparts=':dotsl
+		s|/\./|/|g
+		t dotsl
+		s|/\.$|/|'
+    _G_collapseslashes='s|/\{1,\}|/|g'
+    _G_finalslash='s|/*$|/|'
+
+    # Start from root dir and reassemble the path.
+    func_normal_abspath_result=
+    func_normal_abspath_tpath=$1
+    func_normal_abspath_altnamespace=
+    case $func_normal_abspath_tpath in
+      "")
+        # Empty path, that just means $cwd.
+        func_stripname '' '/' "`pwd`"
+        func_normal_abspath_result=$func_stripname_result
+        return
+        ;;
+      # The next three entries are used to spot a run of precisely
+      # two leading slashes without using negated character classes;
+      # we take advantage of case's first-match behaviour.
+      ///*)
+        # Unusual form of absolute path, do nothing.
+        ;;
+      //*)
+        # Not necessarily an ordinary path; POSIX reserves leading '//'
+        # and for example Cygwin uses it to access remote file shares
+        # over CIFS/SMB, so we conserve a leading double slash if found.
+        func_normal_abspath_altnamespace=/
+        ;;
+      /*)
+        # Absolute path, do nothing.
+        ;;
+      *)
+        # Relative path, prepend $cwd.
+        func_normal_abspath_tpath=`pwd`/$func_normal_abspath_tpath
+        ;;
+    esac
+
+    # Cancel out all the simple stuff to save iterations.  We also want
+    # the path to end with a slash for ease of parsing, so make sure
+    # there is one (and only one) here.
+    func_normal_abspath_tpath=`$ECHO "$func_normal_abspath_tpath" | $SED \
+          -e "$_G_removedotparts" -e "$_G_collapseslashes" -e "$_G_finalslash"`
+    while :; do
+      # Processed it all yet?
+      if test / = "$func_normal_abspath_tpath"; then
+        # If we ascended to the root using ".." the result may be empty now.
+        if test -z "$func_normal_abspath_result"; then
+          func_normal_abspath_result=/
+        fi
+        break
+      fi
+      func_normal_abspath_tcomponent=`$ECHO "$func_normal_abspath_tpath" | $SED \
+          -e "$_G_pathcar"`
+      func_normal_abspath_tpath=`$ECHO "$func_normal_abspath_tpath" | $SED \
+          -e "$_G_pathcdr"`
+      # Figure out what to do with it
+      case $func_normal_abspath_tcomponent in
+        "")
+          # Trailing empty path component, ignore it.
+          ;;
+        ..)
+          # Parent dir; strip last assembled component from result.
+          func_dirname "$func_normal_abspath_result"
+          func_normal_abspath_result=$func_dirname_result
+          ;;
+        *)
+          # Actual path component, append it.
+          func_append func_normal_abspath_result "/$func_normal_abspath_tcomponent"
+          ;;
+      esac
+    done
+    # Restore leading double-slash if one was found on entry.
+    func_normal_abspath_result=$func_normal_abspath_altnamespace$func_normal_abspath_result
+}
+
+
+# func_notquiet ARG...
+# --------------------
+# Echo program name prefixed message only when not in quiet mode.
+func_notquiet ()
+{
+    $debug_cmd
+
+    $opt_quiet || func_echo ${1+"$@"}
+
+    # A bug in bash halts the script if the last line of a function
+    # fails when set -e is in force, so we need another command to
+    # work around that:
+    :
+}
+
+
+# func_relative_path SRCDIR DSTDIR
+# --------------------------------
+# Set func_relative_path_result to the relative path from SRCDIR to DSTDIR.
+func_relative_path ()
+{
+    $debug_cmd
+
+    func_relative_path_result=
+    func_normal_abspath "$1"
+    func_relative_path_tlibdir=$func_normal_abspath_result
+    func_normal_abspath "$2"
+    func_relative_path_tbindir=$func_normal_abspath_result
+
+    # Ascend the tree starting from libdir
+    while :; do
+      # check if we have found a prefix of bindir
+      case $func_relative_path_tbindir in
+        $func_relative_path_tlibdir)
+          # found an exact match
+          func_relative_path_tcancelled=
+          break
+          ;;
+        $func_relative_path_tlibdir*)
+          # found a matching prefix
+          func_stripname "$func_relative_path_tlibdir" '' "$func_relative_path_tbindir"
+          func_relative_path_tcancelled=$func_stripname_result
+          if test -z "$func_relative_path_result"; then
+            func_relative_path_result=.
+          fi
+          break
+          ;;
+        *)
+          func_dirname $func_relative_path_tlibdir
+          func_relative_path_tlibdir=$func_dirname_result
+          if test -z "$func_relative_path_tlibdir"; then
+            # Have to descend all the way to the root!
+            func_relative_path_result=../$func_relative_path_result
+            func_relative_path_tcancelled=$func_relative_path_tbindir
+            break
+          fi
+          func_relative_path_result=../$func_relative_path_result
+          ;;
+      esac
+    done
+
+    # Now calculate path; take care to avoid doubling-up slashes.
+    func_stripname '' '/' "$func_relative_path_result"
+    func_relative_path_result=$func_stripname_result
+    func_stripname '/' '/' "$func_relative_path_tcancelled"
+    if test -n "$func_stripname_result"; then
+      func_append func_relative_path_result "/$func_stripname_result"
+    fi
+
+    # Normalisation. If bindir is libdir, return '.' else relative path.
+    if test -n "$func_relative_path_result"; then
+      func_stripname './' '' "$func_relative_path_result"
+      func_relative_path_result=$func_stripname_result
+    fi
+
+    test -n "$func_relative_path_result" || func_relative_path_result=.
+
+    :
+}
+
+
+# func_quote_for_eval ARG...
+# --------------------------
+# Aesthetically quote ARGs to be evaled later.
+# This function returns two values:
+#   i) func_quote_for_eval_result
+#      double-quoted, suitable for a subsequent eval
+#  ii) func_quote_for_eval_unquoted_result
+#      has all characters that are still active within double
+#      quotes backslashified.
+func_quote_for_eval ()
+{
+    $debug_cmd
+
+    func_quote_for_eval_unquoted_result=
+    func_quote_for_eval_result=
+    while test 0 -lt $#; do
+      case $1 in
+        *[\\\`\"\$]*)
+	  _G_unquoted_arg=`printf '%s\n' "$1" |$SED "$sed_quote_subst"` ;;
+        *)
+          _G_unquoted_arg=$1 ;;
+      esac
+      if test -n "$func_quote_for_eval_unquoted_result"; then
+	func_append func_quote_for_eval_unquoted_result " $_G_unquoted_arg"
+      else
+        func_append func_quote_for_eval_unquoted_result "$_G_unquoted_arg"
+      fi
+
+      case $_G_unquoted_arg in
+        # Double-quote args containing shell metacharacters to delay
+        # word splitting, command substitution and variable expansion
+        # for a subsequent eval.
+        # Many Bourne shells cannot handle close brackets correctly
+        # in scan sets, so we specify it separately.
+        *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
+          _G_quoted_arg=\"$_G_unquoted_arg\"
+          ;;
+        *)
+          _G_quoted_arg=$_G_unquoted_arg
+	  ;;
+      esac
+
+      if test -n "$func_quote_for_eval_result"; then
+	func_append func_quote_for_eval_result " $_G_quoted_arg"
+      else
+        func_append func_quote_for_eval_result "$_G_quoted_arg"
+      fi
+      shift
+    done
+}
+
+
+# func_quote_for_expand ARG
+# -------------------------
+# Aesthetically quote ARG to be evaled later; same as above,
+# but do not quote variable references.
+func_quote_for_expand ()
+{
+    $debug_cmd
+
+    case $1 in
+      *[\\\`\"]*)
+	_G_arg=`$ECHO "$1" | $SED \
+	    -e "$sed_double_quote_subst" -e "$sed_double_backslash"` ;;
+      *)
+        _G_arg=$1 ;;
+    esac
+
+    case $_G_arg in
+      # Double-quote args containing shell metacharacters to delay
+      # word splitting and command substitution for a subsequent eval.
+      # Many Bourne shells cannot handle close brackets correctly
+      # in scan sets, so we specify it separately.
+      *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
+        _G_arg=\"$_G_arg\"
+        ;;
+    esac
+
+    func_quote_for_expand_result=$_G_arg
+}
+
+
+# func_stripname PREFIX SUFFIX NAME
+# ---------------------------------
+# strip PREFIX and SUFFIX from NAME, and store in func_stripname_result.
+# PREFIX and SUFFIX must not contain globbing or regex special
+# characters, hashes, percent signs, but SUFFIX may contain a leading
+# dot (in which case that matches only a dot).
+if test yes = "$_G_HAVE_XSI_OPS"; then
+  eval 'func_stripname ()
+  {
+    $debug_cmd
+
+    # pdksh 5.2.14 does not do ${X%$Y} correctly if both X and Y are
+    # positional parameters, so assign one to ordinary variable first.
+    func_stripname_result=$3
+    func_stripname_result=${func_stripname_result#"$1"}
+    func_stripname_result=${func_stripname_result%"$2"}
+  }'
+else
+  func_stripname ()
+  {
+    $debug_cmd
+
+    case $2 in
+      .*) func_stripname_result=`$ECHO "$3" | $SED -e "s%^$1%%" -e "s%\\\\$2\$%%"`;;
+      *)  func_stripname_result=`$ECHO "$3" | $SED -e "s%^$1%%" -e "s%$2\$%%"`;;
+    esac
+  }
+fi
+
+
+# func_show_eval CMD [FAIL_EXP]
+# -----------------------------
+# Unless opt_quiet is true, then output CMD.  Then, if opt_dryrun is
+# not true, evaluate CMD.  If the evaluation of CMD fails, and FAIL_EXP
+# is given, then evaluate it.
+func_show_eval ()
+{
+    $debug_cmd
+
+    _G_cmd=$1
+    _G_fail_exp=${2-':'}
+
+    func_quote_for_expand "$_G_cmd"
+    eval "func_notquiet $func_quote_for_expand_result"
+
+    $opt_dry_run || {
+      eval "$_G_cmd"
+      _G_status=$?
+      if test 0 -ne "$_G_status"; then
+	eval "(exit $_G_status); $_G_fail_exp"
+      fi
+    }
+}
+
+
+# func_show_eval_locale CMD [FAIL_EXP]
+# ------------------------------------
+# Unless opt_quiet is true, then output CMD.  Then, if opt_dryrun is
+# not true, evaluate CMD.  If the evaluation of CMD fails, and FAIL_EXP
+# is given, then evaluate it.  Use the saved locale for evaluation.
+func_show_eval_locale ()
+{
+    $debug_cmd
+
+    _G_cmd=$1
+    _G_fail_exp=${2-':'}
+
+    $opt_quiet || {
+      func_quote_for_expand "$_G_cmd"
+      eval "func_echo $func_quote_for_expand_result"
+    }
+
+    $opt_dry_run || {
+      eval "$_G_user_locale
+	    $_G_cmd"
+      _G_status=$?
+      eval "$_G_safe_locale"
+      if test 0 -ne "$_G_status"; then
+	eval "(exit $_G_status); $_G_fail_exp"
+      fi
+    }
+}
+
+
+# func_tr_sh
+# ----------
+# Turn $1 into a string suitable for a shell variable name.
+# Result is stored in $func_tr_sh_result.  All characters
+# not in the set a-zA-Z0-9_ are replaced with '_'. Further,
+# if $1 begins with a digit, a '_' is prepended as well.
+func_tr_sh ()
+{
+    $debug_cmd
+
+    case $1 in
+    [0-9]* | *[!a-zA-Z0-9_]*)
+      func_tr_sh_result=`$ECHO "$1" | $SED -e 's/^\([0-9]\)/_\1/' -e 's/[^a-zA-Z0-9_]/_/g'`
+      ;;
+    * )
+      func_tr_sh_result=$1
+      ;;
+    esac
+}
+
+
+# func_verbose ARG...
+# -------------------
+# Echo program name prefixed message in verbose mode only.
+func_verbose ()
+{
+    $debug_cmd
+
+    $opt_verbose && func_echo "$*"
+
+    :
+}
+
+
+# func_warn_and_continue ARG...
+# -----------------------------
+# Echo program name prefixed warning message to standard error.
+func_warn_and_continue ()
+{
+    $debug_cmd
+
+    $require_term_colors
+
+    func_echo_infix_1 "${tc_red}warning$tc_reset" "$*" >&2
+}
+
+
+# func_warning CATEGORY ARG...
+# ----------------------------
+# Echo program name prefixed warning message to standard error. Warning
+# messages can be filtered according to CATEGORY, where this function
+# elides messages where CATEGORY is not listed in the global variable
+# 'opt_warning_types'.
+func_warning ()
+{
+    $debug_cmd
+
+    # CATEGORY must be in the warning_categories list!
+    case " $warning_categories " in
+      *" $1 "*) ;;
+      *) func_internal_error "invalid warning category '$1'" ;;
+    esac
+
+    _G_category=$1
+    shift
+
+    case " $opt_warning_types " in
+      *" $_G_category "*) $warning_func ${1+"$@"} ;;
+    esac
+}
+
+
+# func_sort_ver VER1 VER2
+# -----------------------
+# 'sort -V' is not generally available.
+# Note this deviates from the version comparison in automake
+# in that it treats 1.5 < 1.5.0, and treats 1.4.4a < 1.4-p3a
+# but this should suffice as we won't be specifying old
+# version formats or redundant trailing .0 in bootstrap.conf.
+# If we did want full compatibility then we should probably
+# use m4_version_compare from autoconf.
+func_sort_ver ()
+{
+    $debug_cmd
+
+    printf '%s\n%s\n' "$1" "$2" \
+      | sort -t. -k 1,1n -k 2,2n -k 3,3n -k 4,4n -k 5,5n -k 6,6n -k 7,7n -k 8,8n -k 9,9n
+}
+
+# func_lt_ver PREV CURR
+# ---------------------
+# Return true if PREV and CURR are in the correct order according to
+# func_sort_ver, otherwise false.  Use it like this:
+#
+#  func_lt_ver "$prev_ver" "$proposed_ver" || func_fatal_error "..."
+func_lt_ver ()
+{
+    $debug_cmd
+
+    test "x$1" = x`func_sort_ver "$1" "$2" | $SED 1q`
+}
+
+
+# Local variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-pattern: "10/scriptversion=%:y-%02m-%02d.%02H; # UTC"
+# time-stamp-time-zone: "UTC"
+# End:
+#! /bin/sh
+
+# Set a version string for this script.
+scriptversion=2014-01-07.03; # UTC
+
+# A portable, pluggable option parser for Bourne shell.
+# Written by Gary V. Vaughan, 2010
+
+# Copyright (C) 2010-2015 Free Software Foundation, Inc.
+# This is free software; see the source for copying conditions.  There is NO
+# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Please report bugs or propose patches to gary@gnu.org.
+
+
+## ------ ##
+## Usage. ##
+## ------ ##
+
+# This file is a library for parsing options in your shell scripts along
+# with assorted other useful supporting features that you can make use
+# of too.
+#
+# For the simplest scripts you might need only:
+#
+#   #!/bin/sh
+#   . relative/path/to/funclib.sh
+#   . relative/path/to/options-parser
+#   scriptversion=1.0
+#   func_options ${1+"$@"}
+#   eval set dummy "$func_options_result"; shift
+#   ...rest of your script...
+#
+# In order for the '--version' option to work, you will need to have a
+# suitably formatted comment like the one at the top of this file
+# starting with '# Written by ' and ending with '# warranty; '.
+#
+# For '-h' and '--help' to work, you will also need a one line
+# description of your script's purpose in a comment directly above the
+# '# Written by ' line, like the one at the top of this file.
+#
+# The default options also support '--debug', which will turn on shell
+# execution tracing (see the comment above debug_cmd below for another
+# use), and '--verbose' and the func_verbose function to allow your script
+# to display verbose messages only when your user has specified
+# '--verbose'.
+#
+# After sourcing this file, you can plug processing for additional
+# options by amending the variables from the 'Configuration' section
+# below, and following the instructions in the 'Option parsing'
+# section further down.
+
+## -------------- ##
+## Configuration. ##
+## -------------- ##
+
+# You should override these variables in your script after sourcing this
+# file so that they reflect the customisations you have added to the
+# option parser.
+
+# The usage line for option parsing errors and the start of '-h' and
+# '--help' output messages. You can embed shell variables for delayed
+# expansion at the time the message is displayed, but you will need to
+# quote other shell meta-characters carefully to prevent them being
+# expanded when the contents are evaled.
+usage='$progpath [OPTION]...'
+
+# Short help message in response to '-h' and '--help'.  Add to this or
+# override it after sourcing this library to reflect the full set of
+# options your script accepts.
+usage_message="\
+       --debug        enable verbose shell tracing
+   -W, --warnings=CATEGORY
+                      report the warnings falling in CATEGORY [all]
+   -v, --verbose      verbosely report processing
+       --version      print version information and exit
+   -h, --help         print short or long help message and exit
+"
+
+# Additional text appended to 'usage_message' in response to '--help'.
+long_help_message="
+Warning categories include:
+       'all'          show all warnings
+       'none'         turn off all the warnings
+       'error'        warnings are treated as fatal errors"
+
+# Help message printed before fatal option parsing errors.
+fatal_help="Try '\$progname --help' for more information."
+
+
+
+## ------------------------- ##
+## Hook function management. ##
+## ------------------------- ##
+
+# This section contains functions for adding, removing, and running hooks
+# to the main code.  A hook is just a named list of of function, that can
+# be run in order later on.
+
+# func_hookable FUNC_NAME
+# -----------------------
+# Declare that FUNC_NAME will run hooks added with
+# 'func_add_hook FUNC_NAME ...'.
+func_hookable ()
+{
+    $debug_cmd
+
+    func_append hookable_fns " $1"
+}
+
+
+# func_add_hook FUNC_NAME HOOK_FUNC
+# ---------------------------------
+# Request that FUNC_NAME call HOOK_FUNC before it returns.  FUNC_NAME must
+# first have been declared "hookable" by a call to 'func_hookable'.
+func_add_hook ()
+{
+    $debug_cmd
+
+    case " $hookable_fns " in
+      *" $1 "*) ;;
+      *) func_fatal_error "'$1' does not accept hook functions." ;;
+    esac
+
+    eval func_append ${1}_hooks '" $2"'
+}
+
+
+# func_remove_hook FUNC_NAME HOOK_FUNC
+# ------------------------------------
+# Remove HOOK_FUNC from the list of functions called by FUNC_NAME.
+func_remove_hook ()
+{
+    $debug_cmd
+
+    eval ${1}_hooks='`$ECHO "\$'$1'_hooks" |$SED "s| '$2'||"`'
+}
+
+
+# func_run_hooks FUNC_NAME [ARG]...
+# ---------------------------------
+# Run all hook functions registered to FUNC_NAME.
+# It is assumed that the list of hook functions contains nothing more
+# than a whitespace-delimited list of legal shell function names, and
+# no effort is wasted trying to catch shell meta-characters or preserve
+# whitespace.
+func_run_hooks ()
+{
+    $debug_cmd
+
+    case " $hookable_fns " in
+      *" $1 "*) ;;
+      *) func_fatal_error "'$1' does not support hook funcions.n" ;;
+    esac
+
+    eval _G_hook_fns=\$$1_hooks; shift
+
+    for _G_hook in $_G_hook_fns; do
+      eval $_G_hook '"$@"'
+
+      # store returned options list back into positional
+      # parameters for next 'cmd' execution.
+      eval _G_hook_result=\$${_G_hook}_result
+      eval set dummy "$_G_hook_result"; shift
+    done
+
+    func_quote_for_eval ${1+"$@"}
+    func_run_hooks_result=$func_quote_for_eval_result
+}
+
+
+
+## --------------- ##
+## Option parsing. ##
+## --------------- ##
+
+# In order to add your own option parsing hooks, you must accept the
+# full positional parameter list in your hook function, remove any
+# options that you action, and then pass back the remaining unprocessed
+# options in '<hooked_function_name>_result', escaped suitably for
+# 'eval'.  Like this:
+#
+#    my_options_prep ()
+#    {
+#        $debug_cmd
+#
+#        # Extend the existing usage message.
+#        usage_message=$usage_message'
+#      -s, --silent       don'\''t print informational messages
+#    '
+#
+#        func_quote_for_eval ${1+"$@"}
+#        my_options_prep_result=$func_quote_for_eval_result
+#    }
+#    func_add_hook func_options_prep my_options_prep
+#
+#
+#    my_silent_option ()
+#    {
+#        $debug_cmd
+#
+#        # Note that for efficiency, we parse as many options as we can
+#        # recognise in a loop before passing the remainder back to the
+#        # caller on the first unrecognised argument we encounter.
+#        while test $# -gt 0; do
+#          opt=$1; shift
+#          case $opt in
+#            --silent|-s) opt_silent=: ;;
+#            # Separate non-argument short options:
+#            -s*)         func_split_short_opt "$_G_opt"
+#                         set dummy "$func_split_short_opt_name" \
+#                             "-$func_split_short_opt_arg" ${1+"$@"}
+#                         shift
+#                         ;;
+#            *)            set dummy "$_G_opt" "$*"; shift; break ;;
+#          esac
+#        done
+#
+#        func_quote_for_eval ${1+"$@"}
+#        my_silent_option_result=$func_quote_for_eval_result
+#    }
+#    func_add_hook func_parse_options my_silent_option
+#
+#
+#    my_option_validation ()
+#    {
+#        $debug_cmd
+#
+#        $opt_silent && $opt_verbose && func_fatal_help "\
+#    '--silent' and '--verbose' options are mutually exclusive."
+#
+#        func_quote_for_eval ${1+"$@"}
+#        my_option_validation_result=$func_quote_for_eval_result
+#    }
+#    func_add_hook func_validate_options my_option_validation
+#
+# You'll alse need to manually amend $usage_message to reflect the extra
+# options you parse.  It's preferable to append if you can, so that
+# multiple option parsing hooks can be added safely.
+
+
+# func_options [ARG]...
+# ---------------------
+# All the functions called inside func_options are hookable. See the
+# individual implementations for details.
+func_hookable func_options
+func_options ()
+{
+    $debug_cmd
+
+    func_options_prep ${1+"$@"}
+    eval func_parse_options \
+        ${func_options_prep_result+"$func_options_prep_result"}
+    eval func_validate_options \
+        ${func_parse_options_result+"$func_parse_options_result"}
+
+    eval func_run_hooks func_options \
+        ${func_validate_options_result+"$func_validate_options_result"}
+
+    # save modified positional parameters for caller
+    func_options_result=$func_run_hooks_result
+}
+
+
+# func_options_prep [ARG]...
+# --------------------------
+# All initialisations required before starting the option parse loop.
+# Note that when calling hook functions, we pass through the list of
+# positional parameters.  If a hook function modifies that list, and
+# needs to propogate that back to rest of this script, then the complete
+# modified list must be put in 'func_run_hooks_result' before
+# returning.
+func_hookable func_options_prep
+func_options_prep ()
+{
+    $debug_cmd
+
+    # Option defaults:
+    opt_verbose=false
+    opt_warning_types=
+
+    func_run_hooks func_options_prep ${1+"$@"}
+
+    # save modified positional parameters for caller
+    func_options_prep_result=$func_run_hooks_result
+}
+
+
+# func_parse_options [ARG]...
+# ---------------------------
+# The main option parsing loop.
+func_hookable func_parse_options
+func_parse_options ()
+{
+    $debug_cmd
+
+    func_parse_options_result=
+
+    # this just eases exit handling
+    while test $# -gt 0; do
+      # Defer to hook functions for initial option parsing, so they
+      # get priority in the event of reusing an option name.
+      func_run_hooks func_parse_options ${1+"$@"}
+
+      # Adjust func_parse_options positional parameters to match
+      eval set dummy "$func_run_hooks_result"; shift
+
+      # Break out of the loop if we already parsed every option.
+      test $# -gt 0 || break
+
+      _G_opt=$1
+      shift
+      case $_G_opt in
+        --debug|-x)   debug_cmd='set -x'
+                      func_echo "enabling shell trace mode"
+                      $debug_cmd
+                      ;;
+
+        --no-warnings|--no-warning|--no-warn)
+                      set dummy --warnings none ${1+"$@"}
+                      shift
+		      ;;
+
+        --warnings|--warning|-W)
+                      test $# = 0 && func_missing_arg $_G_opt && break
+                      case " $warning_categories $1" in
+                        *" $1 "*)
+                          # trailing space prevents matching last $1 above
+                          func_append_uniq opt_warning_types " $1"
+                          ;;
+                        *all)
+                          opt_warning_types=$warning_categories
+                          ;;
+                        *none)
+                          opt_warning_types=none
+                          warning_func=:
+                          ;;
+                        *error)
+                          opt_warning_types=$warning_categories
+                          warning_func=func_fatal_error
+                          ;;
+                        *)
+                          func_fatal_error \
+                             "unsupported warning category: '$1'"
+                          ;;
+                      esac
+                      shift
+                      ;;
+
+        --verbose|-v) opt_verbose=: ;;
+        --version)    func_version ;;
+        -\?|-h)       func_usage ;;
+        --help)       func_help ;;
+
+	# Separate optargs to long options (plugins may need this):
+	--*=*)        func_split_equals "$_G_opt"
+	              set dummy "$func_split_equals_lhs" \
+                          "$func_split_equals_rhs" ${1+"$@"}
+                      shift
+                      ;;
+
+       # Separate optargs to short options:
+        -W*)
+                      func_split_short_opt "$_G_opt"
+                      set dummy "$func_split_short_opt_name" \
+                          "$func_split_short_opt_arg" ${1+"$@"}
+                      shift
+                      ;;
+
+        # Separate non-argument short options:
+        -\?*|-h*|-v*|-x*)
+                      func_split_short_opt "$_G_opt"
+                      set dummy "$func_split_short_opt_name" \
+                          "-$func_split_short_opt_arg" ${1+"$@"}
+                      shift
+                      ;;
+
+        --)           break ;;
+        -*)           func_fatal_help "unrecognised option: '$_G_opt'" ;;
+        *)            set dummy "$_G_opt" ${1+"$@"}; shift; break ;;
+      esac
+    done
+
+    # save modified positional parameters for caller
+    func_quote_for_eval ${1+"$@"}
+    func_parse_options_result=$func_quote_for_eval_result
+}
+
+
+# func_validate_options [ARG]...
+# ------------------------------
+# Perform any sanity checks on option settings and/or unconsumed
+# arguments.
+func_hookable func_validate_options
+func_validate_options ()
+{
+    $debug_cmd
+
+    # Display all warnings if -W was not given.
+    test -n "$opt_warning_types" || opt_warning_types=" $warning_categories"
+
+    func_run_hooks func_validate_options ${1+"$@"}
+
+    # Bail if the options were screwed!
+    $exit_cmd $EXIT_FAILURE
+
+    # save modified positional parameters for caller
+    func_validate_options_result=$func_run_hooks_result
+}
+
+
+
+## ----------------- ##
+## Helper functions. ##
+## ----------------- ##
+
+# This section contains the helper functions used by the rest of the
+# hookable option parser framework in ascii-betical order.
+
+
+# func_fatal_help ARG...
+# ----------------------
+# Echo program name prefixed message to standard error, followed by
+# a help hint, and exit.
+func_fatal_help ()
+{
+    $debug_cmd
+
+    eval \$ECHO \""Usage: $usage"\"
+    eval \$ECHO \""$fatal_help"\"
+    func_error ${1+"$@"}
+    exit $EXIT_FAILURE
+}
+
+
+# func_help
+# ---------
+# Echo long help message to standard output and exit.
+func_help ()
+{
+    $debug_cmd
+
+    func_usage_message
+    $ECHO "$long_help_message"
+    exit 0
+}
+
+
+# func_missing_arg ARGNAME
+# ------------------------
+# Echo program name prefixed message to standard error and set global
+# exit_cmd.
+func_missing_arg ()
+{
+    $debug_cmd
+
+    func_error "Missing argument for '$1'."
+    exit_cmd=exit
+}
+
+
+# func_split_equals STRING
+# ------------------------
+# Set func_split_equals_lhs and func_split_equals_rhs shell variables after
+# splitting STRING at the '=' sign.
+test -z "$_G_HAVE_XSI_OPS" \
+    && (eval 'x=a/b/c;
+      test 5aa/bb/cc = "${#x}${x%%/*}${x%/*}${x#*/}${x##*/}"') 2>/dev/null \
+    && _G_HAVE_XSI_OPS=yes
+
+if test yes = "$_G_HAVE_XSI_OPS"
+then
+  # This is an XSI compatible shell, allowing a faster implementation...
+  eval 'func_split_equals ()
+  {
+      $debug_cmd
+
+      func_split_equals_lhs=${1%%=*}
+      func_split_equals_rhs=${1#*=}
+      test "x$func_split_equals_lhs" = "x$1" \
+        && func_split_equals_rhs=
+  }'
+else
+  # ...otherwise fall back to using expr, which is often a shell builtin.
+  func_split_equals ()
+  {
+      $debug_cmd
+
+      func_split_equals_lhs=`expr "x$1" : 'x\([^=]*\)'`
+      func_split_equals_rhs=
+      test "x$func_split_equals_lhs" = "x$1" \
+        || func_split_equals_rhs=`expr "x$1" : 'x[^=]*=\(.*\)$'`
+  }
+fi #func_split_equals
+
+
+# func_split_short_opt SHORTOPT
+# -----------------------------
+# Set func_split_short_opt_name and func_split_short_opt_arg shell
+# variables after splitting SHORTOPT after the 2nd character.
+if test yes = "$_G_HAVE_XSI_OPS"
+then
+  # This is an XSI compatible shell, allowing a faster implementation...
+  eval 'func_split_short_opt ()
+  {
+      $debug_cmd
+
+      func_split_short_opt_arg=${1#??}
+      func_split_short_opt_name=${1%"$func_split_short_opt_arg"}
+  }'
+else
+  # ...otherwise fall back to using expr, which is often a shell builtin.
+  func_split_short_opt ()
+  {
+      $debug_cmd
+
+      func_split_short_opt_name=`expr "x$1" : 'x-\(.\)'`
+      func_split_short_opt_arg=`expr "x$1" : 'x-.\(.*\)$'`
+  }
+fi #func_split_short_opt
+
+
+# func_usage
+# ----------
+# Echo short help message to standard output and exit.
+func_usage ()
+{
+    $debug_cmd
+
+    func_usage_message
+    $ECHO "Run '$progname --help |${PAGER-more}' for full usage"
+    exit 0
+}
+
+
+# func_usage_message
+# ------------------
+# Echo short help message to standard output.
+func_usage_message ()
+{
+    $debug_cmd
+
+    eval \$ECHO \""Usage: $usage"\"
+    echo
+    $SED -n 's|^# ||
+        /^Written by/{
+          x;p;x
+        }
+	h
+	/^Written by/q' < "$progpath"
+    echo
+    eval \$ECHO \""$usage_message"\"
+}
+
+
+# func_version
+# ------------
+# Echo version message to standard output and exit.
+func_version ()
+{
+    $debug_cmd
+
+    printf '%s\n' "$progname $scriptversion"
+    $SED -n '
+        /(C)/!b go
+        :more
+        /\./!{
+          N
+          s|\n# | |
+          b more
+        }
+        :go
+        /^# Written by /,/# warranty; / {
+          s|^# ||
+          s|^# *$||
+          s|\((C)\)[ 0-9,-]*[ ,-]\([1-9][0-9]* \)|\1 \2|
+          p
+        }
+        /^# Written by / {
+          s|^# ||
+          p
+        }
+        /^warranty; /q' < "$progpath"
+
+    exit $?
+}
+
+
+# Local variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-pattern: "10/scriptversion=%:y-%02m-%02d.%02H; # UTC"
+# time-stamp-time-zone: "UTC"
+# End:
+
+# Set a version string.
+scriptversion='(GNU libtool) 2.4.6'
+
+
+# func_echo ARG...
+# ----------------
+# Libtool also displays the current mode in messages, so override
+# funclib.sh func_echo with this custom definition.
+func_echo ()
+{
+    $debug_cmd
+
+    _G_message=$*
+
+    func_echo_IFS=$IFS
+    IFS=$nl
+    for _G_line in $_G_message; do
+      IFS=$func_echo_IFS
+      $ECHO "$progname${opt_mode+: $opt_mode}: $_G_line"
+    done
+    IFS=$func_echo_IFS
+}
+
+
+# func_warning ARG...
+# -------------------
+# Libtool warnings are not categorized, so override funclib.sh
+# func_warning with this simpler definition.
+func_warning ()
+{
+    $debug_cmd
+
+    $warning_func ${1+"$@"}
+}
+
+
+## ---------------- ##
+## Options parsing. ##
+## ---------------- ##
+
+# Hook in the functions to make sure our own options are parsed during
+# the option parsing loop.
+
+usage='$progpath [OPTION]... [MODE-ARG]...'
+
+# Short help message in response to '-h'.
+usage_message="Options:
+       --config             show all configuration variables
+       --debug              enable verbose shell tracing
+   -n, --dry-run            display commands without modifying any files
+       --features           display basic configuration information and exit
+       --mode=MODE          use operation mode MODE
+       --no-warnings        equivalent to '-Wnone'
+       --preserve-dup-deps  don't remove duplicate dependency libraries
+       --quiet, --silent    don't print informational messages
+       --tag=TAG            use configuration variables from tag TAG
+   -v, --verbose            print more informational messages than default
+       --version            print version information
+   -W, --warnings=CATEGORY  report the warnings falling in CATEGORY [all]
+   -h, --help, --help-all   print short, long, or detailed help message
+"
+
+# Additional text appended to 'usage_message' in response to '--help'.
+func_help ()
+{
+    $debug_cmd
+
+    func_usage_message
+    $ECHO "$long_help_message
+
+MODE must be one of the following:
+
+       clean           remove files from the build directory
+       compile         compile a source file into a libtool object
+       execute         automatically set library path, then run a program
+       finish          complete the installation of libtool libraries
+       install         install libraries or executables
+       link            create a library or an executable
+       uninstall       remove libraries from an installed directory
+
+MODE-ARGS vary depending on the MODE.  When passed as first option,
+'--mode=MODE' may be abbreviated as 'MODE' or a unique abbreviation of that.
+Try '$progname --help --mode=MODE' for a more detailed description of MODE.
+
+When reporting a bug, please describe a test case to reproduce it and
+include the following information:
+
+       host-triplet:   $host
+       shell:          $SHELL
+       compiler:       $LTCC
+       compiler flags: $LTCFLAGS
+       linker:         $LD (gnu? $with_gnu_ld)
+       version:        $progname (GNU libtool) 2.4.6
+       automake:       `($AUTOMAKE --version) 2>/dev/null |$SED 1q`
+       autoconf:       `($AUTOCONF --version) 2>/dev/null |$SED 1q`
+
+Report bugs to <bug-libtool@gnu.org>.
+GNU libtool home page: <http://www.gnu.org/software/libtool/>.
+General help using GNU software: <http://www.gnu.org/gethelp/>."
+    exit 0
+}
+
+
+# func_lo2o OBJECT-NAME
+# ---------------------
+# Transform OBJECT-NAME from a '.lo' suffix to the platform specific
+# object suffix.
+
+lo2o=s/\\.lo\$/.$objext/
+o2lo=s/\\.$objext\$/.lo/
+
+if test yes = "$_G_HAVE_XSI_OPS"; then
+  eval 'func_lo2o ()
+  {
+    case $1 in
+      *.lo) func_lo2o_result=${1%.lo}.$objext ;;
+      *   ) func_lo2o_result=$1               ;;
+    esac
+  }'
+
+  # func_xform LIBOBJ-OR-SOURCE
+  # ---------------------------
+  # Transform LIBOBJ-OR-SOURCE from a '.o' or '.c' (or otherwise)
+  # suffix to a '.lo' libtool-object suffix.
+  eval 'func_xform ()
+  {
+    func_xform_result=${1%.*}.lo
+  }'
+else
+  # ...otherwise fall back to using sed.
+  func_lo2o ()
+  {
+    func_lo2o_result=`$ECHO "$1" | $SED "$lo2o"`
+  }
+
+  func_xform ()
+  {
+    func_xform_result=`$ECHO "$1" | $SED 's|\.[^.]*$|.lo|'`
+  }
+fi
+
+
+# func_fatal_configuration ARG...
+# -------------------------------
+# Echo program name prefixed message to standard error, followed by
+# a configuration failure hint, and exit.
+func_fatal_configuration ()
+{
+    func__fatal_error ${1+"$@"} \
+      "See the $PACKAGE documentation for more information." \
+      "Fatal configuration error."
+}
+
+
+# func_config
+# -----------
+# Display the configuration for all the tags in this script.
+func_config ()
+{
+    re_begincf='^# ### BEGIN LIBTOOL'
+    re_endcf='^# ### END LIBTOOL'
+
+    # Default configuration.
+    $SED "1,/$re_begincf CONFIG/d;/$re_endcf CONFIG/,\$d" < "$progpath"
+
+    # Now print the configurations for the tags.
+    for tagname in $taglist; do
+      $SED -n "/$re_begincf TAG CONFIG: $tagname\$/,/$re_endcf TAG CONFIG: $tagname\$/p" < "$progpath"
+    done
+
+    exit $?
+}
+
+
+# func_features
+# -------------
+# Display the features supported by this script.
+func_features ()
+{
+    echo "host: $host"
+    if test yes = "$build_libtool_libs"; then
+      echo "enable shared libraries"
+    else
+      echo "disable shared libraries"
+    fi
+    if test yes = "$build_old_libs"; then
+      echo "enable static libraries"
+    else
+      echo "disable static libraries"
+    fi
+
+    exit $?
+}
+
+
+# func_enable_tag TAGNAME
+# -----------------------
+# Verify that TAGNAME is valid, and either flag an error and exit, or
+# enable the TAGNAME tag.  We also add TAGNAME to the global $taglist
+# variable here.
+func_enable_tag ()
+{
+    # Global variable:
+    tagname=$1
+
+    re_begincf="^# ### BEGIN LIBTOOL TAG CONFIG: $tagname\$"
+    re_endcf="^# ### END LIBTOOL TAG CONFIG: $tagname\$"
+    sed_extractcf=/$re_begincf/,/$re_endcf/p
+
+    # Validate tagname.
+    case $tagname in
+      *[!-_A-Za-z0-9,/]*)
+        func_fatal_error "invalid tag name: $tagname"
+        ;;
+    esac
+
+    # Don't test for the "default" C tag, as we know it's
+    # there but not specially marked.
+    case $tagname in
+        CC) ;;
+    *)
+        if $GREP "$re_begincf" "$progpath" >/dev/null 2>&1; then
+	  taglist="$taglist $tagname"
+
+	  # Evaluate the configuration.  Be careful to quote the path
+	  # and the sed script, to avoid splitting on whitespace, but
+	  # also don't use non-portable quotes within backquotes within
+	  # quotes we have to do it in 2 steps:
+	  extractedcf=`$SED -n -e "$sed_extractcf" < "$progpath"`
+	  eval "$extractedcf"
+        else
+	  func_error "ignoring unknown tag $tagname"
+        fi
+        ;;
+    esac
+}
+
+
+# func_check_version_match
+# ------------------------
+# Ensure that we are using m4 macros, and libtool script from the same
+# release of libtool.
+func_check_version_match ()
+{
+    if test "$package_revision" != "$macro_revision"; then
+      if test "$VERSION" != "$macro_version"; then
+        if test -z "$macro_version"; then
+          cat >&2 <<_LT_EOF
+$progname: Version mismatch error.  This is $PACKAGE $VERSION, but the
+$progname: definition of this LT_INIT comes from an older release.
+$progname: You should recreate aclocal.m4 with macros from $PACKAGE $VERSION
+$progname: and run autoconf again.
+_LT_EOF
+        else
+          cat >&2 <<_LT_EOF
+$progname: Version mismatch error.  This is $PACKAGE $VERSION, but the
+$progname: definition of this LT_INIT comes from $PACKAGE $macro_version.
+$progname: You should recreate aclocal.m4 with macros from $PACKAGE $VERSION
+$progname: and run autoconf again.
+_LT_EOF
+        fi
+      else
+        cat >&2 <<_LT_EOF
+$progname: Version mismatch error.  This is $PACKAGE $VERSION, revision $package_revision,
+$progname: but the definition of this LT_INIT comes from revision $macro_revision.
+$progname: You should recreate aclocal.m4 with macros from revision $package_revision
+$progname: of $PACKAGE $VERSION and run autoconf again.
+_LT_EOF
+      fi
+
+      exit $EXIT_MISMATCH
+    fi
+}
+
+
+# libtool_options_prep [ARG]...
+# -----------------------------
+# Preparation for options parsed by libtool.
+libtool_options_prep ()
+{
+    $debug_mode
+
+    # Option defaults:
+    opt_config=false
+    opt_dlopen=
+    opt_dry_run=false
+    opt_help=false
+    opt_mode=
+    opt_preserve_dup_deps=false
+    opt_quiet=false
+
+    nonopt=
+    preserve_args=
+
+    # Shorthand for --mode=foo, only valid as the first argument
+    case $1 in
+    clean|clea|cle|cl)
+      shift; set dummy --mode clean ${1+"$@"}; shift
+      ;;
+    compile|compil|compi|comp|com|co|c)
+      shift; set dummy --mode compile ${1+"$@"}; shift
+      ;;
+    execute|execut|execu|exec|exe|ex|e)
+      shift; set dummy --mode execute ${1+"$@"}; shift
+      ;;
+    finish|finis|fini|fin|fi|f)
+      shift; set dummy --mode finish ${1+"$@"}; shift
+      ;;
+    install|instal|insta|inst|ins|in|i)
+      shift; set dummy --mode install ${1+"$@"}; shift
+      ;;
+    link|lin|li|l)
+      shift; set dummy --mode link ${1+"$@"}; shift
+      ;;
+    uninstall|uninstal|uninsta|uninst|unins|unin|uni|un|u)
+      shift; set dummy --mode uninstall ${1+"$@"}; shift
+      ;;
+    esac
+
+    # Pass back the list of options.
+    func_quote_for_eval ${1+"$@"}
+    libtool_options_prep_result=$func_quote_for_eval_result
+}
+func_add_hook func_options_prep libtool_options_prep
+
+
+# libtool_parse_options [ARG]...
+# ---------------------------------
+# Provide handling for libtool specific options.
+libtool_parse_options ()
+{
+    $debug_cmd
+
+    # Perform our own loop to consume as many options as possible in
+    # each iteration.
+    while test $# -gt 0; do
+      _G_opt=$1
+      shift
+      case $_G_opt in
+        --dry-run|--dryrun|-n)
+                        opt_dry_run=:
+                        ;;
+
+        --config)       func_config ;;
+
+        --dlopen|-dlopen)
+                        opt_dlopen="${opt_dlopen+$opt_dlopen
+}$1"
+                        shift
+                        ;;
+
+        --preserve-dup-deps)
+                        opt_preserve_dup_deps=: ;;
+
+        --features)     func_features ;;
+
+        --finish)       set dummy --mode finish ${1+"$@"}; shift ;;
+
+        --help)         opt_help=: ;;
+
+        --help-all)     opt_help=': help-all' ;;
+
+        --mode)         test $# = 0 && func_missing_arg $_G_opt && break
+                        opt_mode=$1
+                        case $1 in
+                          # Valid mode arguments:
+                          clean|compile|execute|finish|install|link|relink|uninstall) ;;
+
+                          # Catch anything else as an error
+                          *) func_error "invalid argument for $_G_opt"
+                             exit_cmd=exit
+                             break
+                             ;;
+                        esac
+                        shift
+                        ;;
+
+        --no-silent|--no-quiet)
+                        opt_quiet=false
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+        --no-warnings|--no-warning|--no-warn)
+                        opt_warning=false
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+        --no-verbose)
+                        opt_verbose=false
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+        --silent|--quiet)
+                        opt_quiet=:
+                        opt_verbose=false
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+        --tag)          test $# = 0 && func_missing_arg $_G_opt && break
+                        opt_tag=$1
+                        func_append preserve_args " $_G_opt $1"
+                        func_enable_tag "$1"
+                        shift
+                        ;;
+
+        --verbose|-v)   opt_quiet=false
+                        opt_verbose=:
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+	# An option not handled by this hook function:
+        *)		set dummy "$_G_opt" ${1+"$@"};	shift; break  ;;
+      esac
+    done
+
+
+    # save modified positional parameters for caller
+    func_quote_for_eval ${1+"$@"}
+    libtool_parse_options_result=$func_quote_for_eval_result
+}
+func_add_hook func_parse_options libtool_parse_options
+
+
+
+# libtool_validate_options [ARG]...
+# ---------------------------------
+# Perform any sanity checks on option settings and/or unconsumed
+# arguments.
+libtool_validate_options ()
+{
+    # save first non-option argument
+    if test 0 -lt $#; then
+      nonopt=$1
+      shift
+    fi
+
+    # preserve --debug
+    test : = "$debug_cmd" || func_append preserve_args " --debug"
+
+    case $host in
+      # Solaris2 added to fix http://debbugs.gnu.org/cgi/bugreport.cgi?bug=16452
+      # see also: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59788
+      *cygwin* | *mingw* | *pw32* | *cegcc* | *solaris2* | *os2*)
+        # don't eliminate duplications in $postdeps and $predeps
+        opt_duplicate_compiler_generated_deps=:
+        ;;
+      *)
+        opt_duplicate_compiler_generated_deps=$opt_preserve_dup_deps
+        ;;
+    esac
+
+    $opt_help || {
+      # Sanity checks first:
+      func_check_version_match
+
+      test yes != "$build_libtool_libs" \
+        && test yes != "$build_old_libs" \
+        && func_fatal_configuration "not configured to build any kind of library"
+
+      # Darwin sucks
+      eval std_shrext=\"$shrext_cmds\"
+
+      # Only execute mode is allowed to have -dlopen flags.
+      if test -n "$opt_dlopen" && test execute != "$opt_mode"; then
+        func_error "unrecognized option '-dlopen'"
+        $ECHO "$help" 1>&2
+        exit $EXIT_FAILURE
+      fi
+
+      # Change the help message to a mode-specific one.
+      generic_help=$help
+      help="Try '$progname --help --mode=$opt_mode' for more information."
+    }
+
+    # Pass back the unparsed argument list
+    func_quote_for_eval ${1+"$@"}
+    libtool_validate_options_result=$func_quote_for_eval_result
+}
+func_add_hook func_validate_options libtool_validate_options
+
+
+# Process options as early as possible so that --help and --version
+# can return quickly.
+func_options ${1+"$@"}
+eval set dummy "$func_options_result"; shift
+
+
+
+## ----------- ##
+##    Main.    ##
+## ----------- ##
+
+magic='%%%MAGIC variable%%%'
+magic_exe='%%%MAGIC EXE variable%%%'
+
+# Global variables.
+extracted_archives=
+extracted_serial=0
+
+# If this variable is set in any of the actions, the command in it
+# will be execed at the end.  This prevents here-documents from being
+# left over by shells.
+exec_cmd=
+
+
+# A function that is used when there is no print builtin or printf.
+func_fallback_echo ()
+{
+  eval 'cat <<_LTECHO_EOF
+$1
+_LTECHO_EOF'
+}
+
+# func_generated_by_libtool
+# True iff stdin has been generated by Libtool. This function is only
+# a basic sanity check; it will hardly flush out determined imposters.
+func_generated_by_libtool_p ()
+{
+  $GREP "^# Generated by .*$PACKAGE" > /dev/null 2>&1
+}
+
+# func_lalib_p file
+# True iff FILE is a libtool '.la' library or '.lo' object file.
+# This function is only a basic sanity check; it will hardly flush out
+# determined imposters.
+func_lalib_p ()
+{
+    test -f "$1" &&
+      $SED -e 4q "$1" 2>/dev/null | func_generated_by_libtool_p
+}
+
+# func_lalib_unsafe_p file
+# True iff FILE is a libtool '.la' library or '.lo' object file.
+# This function implements the same check as func_lalib_p without
+# resorting to external programs.  To this end, it redirects stdin and
+# closes it afterwards, without saving the original file descriptor.
+# As a safety measure, use it only where a negative result would be
+# fatal anyway.  Works if 'file' does not exist.
+func_lalib_unsafe_p ()
+{
+    lalib_p=no
+    if test -f "$1" && test -r "$1" && exec 5<&0 <"$1"; then
+	for lalib_p_l in 1 2 3 4
+	do
+	    read lalib_p_line
+	    case $lalib_p_line in
+		\#\ Generated\ by\ *$PACKAGE* ) lalib_p=yes; break;;
+	    esac
+	done
+	exec 0<&5 5<&-
+    fi
+    test yes = "$lalib_p"
+}
+
+# func_ltwrapper_script_p file
+# True iff FILE is a libtool wrapper script
+# This function is only a basic sanity check; it will hardly flush out
+# determined imposters.
+func_ltwrapper_script_p ()
+{
+    test -f "$1" &&
+      $lt_truncate_bin < "$1" 2>/dev/null | func_generated_by_libtool_p
+}
+
+# func_ltwrapper_executable_p file
+# True iff FILE is a libtool wrapper executable
+# This function is only a basic sanity check; it will hardly flush out
+# determined imposters.
+func_ltwrapper_executable_p ()
+{
+    func_ltwrapper_exec_suffix=
+    case $1 in
+    *.exe) ;;
+    *) func_ltwrapper_exec_suffix=.exe ;;
+    esac
+    $GREP "$magic_exe" "$1$func_ltwrapper_exec_suffix" >/dev/null 2>&1
+}
+
+# func_ltwrapper_scriptname file
+# Assumes file is an ltwrapper_executable
+# uses $file to determine the appropriate filename for a
+# temporary ltwrapper_script.
+func_ltwrapper_scriptname ()
+{
+    func_dirname_and_basename "$1" "" "."
+    func_stripname '' '.exe' "$func_basename_result"
+    func_ltwrapper_scriptname_result=$func_dirname_result/$objdir/${func_stripname_result}_ltshwrapper
+}
+
+# func_ltwrapper_p file
+# True iff FILE is a libtool wrapper script or wrapper executable
+# This function is only a basic sanity check; it will hardly flush out
+# determined imposters.
+func_ltwrapper_p ()
+{
+    func_ltwrapper_script_p "$1" || func_ltwrapper_executable_p "$1"
+}
+
+
+# func_execute_cmds commands fail_cmd
+# Execute tilde-delimited COMMANDS.
+# If FAIL_CMD is given, eval that upon failure.
+# FAIL_CMD may read-access the current command in variable CMD!
+func_execute_cmds ()
+{
+    $debug_cmd
+
+    save_ifs=$IFS; IFS='~'
+    for cmd in $1; do
+      IFS=$sp$nl
+      eval cmd=\"$cmd\"
+      IFS=$save_ifs
+      func_show_eval "$cmd" "${2-:}"
+    done
+    IFS=$save_ifs
+}
+
+
+# func_source file
+# Source FILE, adding directory component if necessary.
+# Note that it is not necessary on cygwin/mingw to append a dot to
+# FILE even if both FILE and FILE.exe exist: automatic-append-.exe
+# behavior happens only for exec(3), not for open(2)!  Also, sourcing
+# 'FILE.' does not work on cygwin managed mounts.
+func_source ()
+{
+    $debug_cmd
+
+    case $1 in
+    */* | *\\*)	. "$1" ;;
+    *)		. "./$1" ;;
+    esac
+}
+
+
+# func_resolve_sysroot PATH
+# Replace a leading = in PATH with a sysroot.  Store the result into
+# func_resolve_sysroot_result
+func_resolve_sysroot ()
+{
+  func_resolve_sysroot_result=$1
+  case $func_resolve_sysroot_result in
+  =*)
+    func_stripname '=' '' "$func_resolve_sysroot_result"
+    func_resolve_sysroot_result=$lt_sysroot$func_stripname_result
+    ;;
+  esac
+}
+
+# func_replace_sysroot PATH
+# If PATH begins with the sysroot, replace it with = and
+# store the result into func_replace_sysroot_result.
+func_replace_sysroot ()
+{
+  case $lt_sysroot:$1 in
+  ?*:"$lt_sysroot"*)
+    func_stripname "$lt_sysroot" '' "$1"
+    func_replace_sysroot_result='='$func_stripname_result
+    ;;
+  *)
+    # Including no sysroot.
+    func_replace_sysroot_result=$1
+    ;;
+  esac
+}
+
+# func_infer_tag arg
+# Infer tagged configuration to use if any are available and
+# if one wasn't chosen via the "--tag" command line option.
+# Only attempt this if the compiler in the base compile
+# command doesn't match the default compiler.
+# arg is usually of the form 'gcc ...'
+func_infer_tag ()
+{
+    $debug_cmd
+
+    if test -n "$available_tags" && test -z "$tagname"; then
+      CC_quoted=
+      for arg in $CC; do
+	func_append_quoted CC_quoted "$arg"
+      done
+      CC_expanded=`func_echo_all $CC`
+      CC_quoted_expanded=`func_echo_all $CC_quoted`
+      case $@ in
+      # Blanks in the command may have been stripped by the calling shell,
+      # but not from the CC environment variable when configure was run.
+      " $CC "* | "$CC "* | " $CC_expanded "* | "$CC_expanded "* | \
+      " $CC_quoted"* | "$CC_quoted "* | " $CC_quoted_expanded "* | "$CC_quoted_expanded "*) ;;
+      # Blanks at the start of $base_compile will cause this to fail
+      # if we don't check for them as well.
+      *)
+	for z in $available_tags; do
+	  if $GREP "^# ### BEGIN LIBTOOL TAG CONFIG: $z$" < "$progpath" > /dev/null; then
+	    # Evaluate the configuration.
+	    eval "`$SED -n -e '/^# ### BEGIN LIBTOOL TAG CONFIG: '$z'$/,/^# ### END LIBTOOL TAG CONFIG: '$z'$/p' < $progpath`"
+	    CC_quoted=
+	    for arg in $CC; do
+	      # Double-quote args containing other shell metacharacters.
+	      func_append_quoted CC_quoted "$arg"
+	    done
+	    CC_expanded=`func_echo_all $CC`
+	    CC_quoted_expanded=`func_echo_all $CC_quoted`
+	    case "$@ " in
+	    " $CC "* | "$CC "* | " $CC_expanded "* | "$CC_expanded "* | \
+	    " $CC_quoted"* | "$CC_quoted "* | " $CC_quoted_expanded "* | "$CC_quoted_expanded "*)
+	      # The compiler in the base compile command matches
+	      # the one in the tagged configuration.
+	      # Assume this is the tagged configuration we want.
+	      tagname=$z
+	      break
+	      ;;
+	    esac
+	  fi
+	done
+	# If $tagname still isn't set, then no tagged configuration
+	# was found and let the user know that the "--tag" command
+	# line option must be used.
+	if test -z "$tagname"; then
+	  func_echo "unable to infer tagged configuration"
+	  func_fatal_error "specify a tag with '--tag'"
+#	else
+#	  func_verbose "using $tagname tagged configuration"
+	fi
+	;;
+      esac
+    fi
+}
+
+
+
+# func_write_libtool_object output_name pic_name nonpic_name
+# Create a libtool object file (analogous to a ".la" file),
+# but don't create it if we're doing a dry run.
+func_write_libtool_object ()
+{
+    write_libobj=$1
+    if test yes = "$build_libtool_libs"; then
+      write_lobj=\'$2\'
+    else
+      write_lobj=none
+    fi
+
+    if test yes = "$build_old_libs"; then
+      write_oldobj=\'$3\'
+    else
+      write_oldobj=none
+    fi
+
+    $opt_dry_run || {
+      cat >${write_libobj}T <<EOF
+# $write_libobj - a libtool object file
+# Generated by $PROGRAM (GNU $PACKAGE) $VERSION
+#
+# Please DO NOT delete this file!
+# It is necessary for linking the library.
+
+# Name of the PIC object.
+pic_object=$write_lobj
+
+# Name of the non-PIC object
+non_pic_object=$write_oldobj
+
+EOF
+      $MV "${write_libobj}T" "$write_libobj"
+    }
+}
+
+
+##################################################
+# FILE NAME AND PATH CONVERSION HELPER FUNCTIONS #
+##################################################
+
+# func_convert_core_file_wine_to_w32 ARG
+# Helper function used by file name conversion functions when $build is *nix,
+# and $host is mingw, cygwin, or some other w32 environment. Relies on a
+# correctly configured wine environment available, with the winepath program
+# in $build's $PATH.
+#
+# ARG is the $build file name to be converted to w32 format.
+# Result is available in $func_convert_core_file_wine_to_w32_result, and will
+# be empty on error (or when ARG is empty)
+func_convert_core_file_wine_to_w32 ()
+{
+  $debug_cmd
+
+  func_convert_core_file_wine_to_w32_result=$1
+  if test -n "$1"; then
+    # Unfortunately, winepath does not exit with a non-zero error code, so we
+    # are forced to check the contents of stdout. On the other hand, if the
+    # command is not found, the shell will set an exit code of 127 and print
+    # *an error message* to stdout. So we must check for both error code of
+    # zero AND non-empty stdout, which explains the odd construction:
+    func_convert_core_file_wine_to_w32_tmp=`winepath -w "$1" 2>/dev/null`
+    if test "$?" -eq 0 && test -n "$func_convert_core_file_wine_to_w32_tmp"; then
+      func_convert_core_file_wine_to_w32_result=`$ECHO "$func_convert_core_file_wine_to_w32_tmp" |
+        $SED -e "$sed_naive_backslashify"`
+    else
+      func_convert_core_file_wine_to_w32_result=
+    fi
+  fi
+}
+# end: func_convert_core_file_wine_to_w32
+
+
+# func_convert_core_path_wine_to_w32 ARG
+# Helper function used by path conversion functions when $build is *nix, and
+# $host is mingw, cygwin, or some other w32 environment. Relies on a correctly
+# configured wine environment available, with the winepath program in $build's
+# $PATH. Assumes ARG has no leading or trailing path separator characters.
+#
+# ARG is path to be converted from $build format to win32.
+# Result is available in $func_convert_core_path_wine_to_w32_result.
+# Unconvertible file (directory) names in ARG are skipped; if no directory names
+# are convertible, then the result may be empty.
+func_convert_core_path_wine_to_w32 ()
+{
+  $debug_cmd
+
+  # unfortunately, winepath doesn't convert paths, only file names
+  func_convert_core_path_wine_to_w32_result=
+  if test -n "$1"; then
+    oldIFS=$IFS
+    IFS=:
+    for func_convert_core_path_wine_to_w32_f in $1; do
+      IFS=$oldIFS
+      func_convert_core_file_wine_to_w32 "$func_convert_core_path_wine_to_w32_f"
+      if test -n "$func_convert_core_file_wine_to_w32_result"; then
+        if test -z "$func_convert_core_path_wine_to_w32_result"; then
+          func_convert_core_path_wine_to_w32_result=$func_convert_core_file_wine_to_w32_result
+        else
+          func_append func_convert_core_path_wine_to_w32_result ";$func_convert_core_file_wine_to_w32_result"
+        fi
+      fi
+    done
+    IFS=$oldIFS
+  fi
+}
+# end: func_convert_core_path_wine_to_w32
+
+
+# func_cygpath ARGS...
+# Wrapper around calling the cygpath program via LT_CYGPATH. This is used when
+# when (1) $build is *nix and Cygwin is hosted via a wine environment; or (2)
+# $build is MSYS and $host is Cygwin, or (3) $build is Cygwin. In case (1) or
+# (2), returns the Cygwin file name or path in func_cygpath_result (input
+# file name or path is assumed to be in w32 format, as previously converted
+# from $build's *nix or MSYS format). In case (3), returns the w32 file name
+# or path in func_cygpath_result (input file name or path is assumed to be in
+# Cygwin format). Returns an empty string on error.
+#
+# ARGS are passed to cygpath, with the last one being the file name or path to
+# be converted.
+#
+# Specify the absolute *nix (or w32) name to cygpath in the LT_CYGPATH
+# environment variable; do not put it in $PATH.
+func_cygpath ()
+{
+  $debug_cmd
+
+  if test -n "$LT_CYGPATH" && test -f "$LT_CYGPATH"; then
+    func_cygpath_result=`$LT_CYGPATH "$@" 2>/dev/null`
+    if test "$?" -ne 0; then
+      # on failure, ensure result is empty
+      func_cygpath_result=
+    fi
+  else
+    func_cygpath_result=
+    func_error "LT_CYGPATH is empty or specifies non-existent file: '$LT_CYGPATH'"
+  fi
+}
+#end: func_cygpath
+
+
+# func_convert_core_msys_to_w32 ARG
+# Convert file name or path ARG from MSYS format to w32 format.  Return
+# result in func_convert_core_msys_to_w32_result.
+func_convert_core_msys_to_w32 ()
+{
+  $debug_cmd
+
+  # awkward: cmd appends spaces to result
+  func_convert_core_msys_to_w32_result=`( cmd //c echo "$1" ) 2>/dev/null |
+    $SED -e 's/[ ]*$//' -e "$sed_naive_backslashify"`
+}
+#end: func_convert_core_msys_to_w32
+
+
+# func_convert_file_check ARG1 ARG2
+# Verify that ARG1 (a file name in $build format) was converted to $host
+# format in ARG2. Otherwise, emit an error message, but continue (resetting
+# func_to_host_file_result to ARG1).
+func_convert_file_check ()
+{
+  $debug_cmd
+
+  if test -z "$2" && test -n "$1"; then
+    func_error "Could not determine host file name corresponding to"
+    func_error "  '$1'"
+    func_error "Continuing, but uninstalled executables may not work."
+    # Fallback:
+    func_to_host_file_result=$1
+  fi
+}
+# end func_convert_file_check
+
+
+# func_convert_path_check FROM_PATHSEP TO_PATHSEP FROM_PATH TO_PATH
+# Verify that FROM_PATH (a path in $build format) was converted to $host
+# format in TO_PATH. Otherwise, emit an error message, but continue, resetting
+# func_to_host_file_result to a simplistic fallback value (see below).
+func_convert_path_check ()
+{
+  $debug_cmd
+
+  if test -z "$4" && test -n "$3"; then
+    func_error "Could not determine the host path corresponding to"
+    func_error "  '$3'"
+    func_error "Continuing, but uninstalled executables may not work."
+    # Fallback.  This is a deliberately simplistic "conversion" and
+    # should not be "improved".  See libtool.info.
+    if test "x$1" != "x$2"; then
+      lt_replace_pathsep_chars="s|$1|$2|g"
+      func_to_host_path_result=`echo "$3" |
+        $SED -e "$lt_replace_pathsep_chars"`
+    else
+      func_to_host_path_result=$3
+    fi
+  fi
+}
+# end func_convert_path_check
+
+
+# func_convert_path_front_back_pathsep FRONTPAT BACKPAT REPL ORIG
+# Modifies func_to_host_path_result by prepending REPL if ORIG matches FRONTPAT
+# and appending REPL if ORIG matches BACKPAT.
+func_convert_path_front_back_pathsep ()
+{
+  $debug_cmd
+
+  case $4 in
+  $1 ) func_to_host_path_result=$3$func_to_host_path_result
+    ;;
+  esac
+  case $4 in
+  $2 ) func_append func_to_host_path_result "$3"
+    ;;
+  esac
+}
+# end func_convert_path_front_back_pathsep
+
+
+##################################################
+# $build to $host FILE NAME CONVERSION FUNCTIONS #
+##################################################
+# invoked via '$to_host_file_cmd ARG'
+#
+# In each case, ARG is the path to be converted from $build to $host format.
+# Result will be available in $func_to_host_file_result.
+
+
+# func_to_host_file ARG
+# Converts the file name ARG from $build format to $host format. Return result
+# in func_to_host_file_result.
+func_to_host_file ()
+{
+  $debug_cmd
+
+  $to_host_file_cmd "$1"
+}
+# end func_to_host_file
+
+
+# func_to_tool_file ARG LAZY
+# converts the file name ARG from $build format to toolchain format. Return
+# result in func_to_tool_file_result.  If the conversion in use is listed
+# in (the comma separated) LAZY, no conversion takes place.
+func_to_tool_file ()
+{
+  $debug_cmd
+
+  case ,$2, in
+    *,"$to_tool_file_cmd",*)
+      func_to_tool_file_result=$1
+      ;;
+    *)
+      $to_tool_file_cmd "$1"
+      func_to_tool_file_result=$func_to_host_file_result
+      ;;
+  esac
+}
+# end func_to_tool_file
+
+
+# func_convert_file_noop ARG
+# Copy ARG to func_to_host_file_result.
+func_convert_file_noop ()
+{
+  func_to_host_file_result=$1
+}
+# end func_convert_file_noop
+
+
+# func_convert_file_msys_to_w32 ARG
+# Convert file name ARG from (mingw) MSYS to (mingw) w32 format; automatic
+# conversion to w32 is not available inside the cwrapper.  Returns result in
+# func_to_host_file_result.
+func_convert_file_msys_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    func_convert_core_msys_to_w32 "$1"
+    func_to_host_file_result=$func_convert_core_msys_to_w32_result
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_msys_to_w32
+
+
+# func_convert_file_cygwin_to_w32 ARG
+# Convert file name ARG from Cygwin to w32 format.  Returns result in
+# func_to_host_file_result.
+func_convert_file_cygwin_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    # because $build is cygwin, we call "the" cygpath in $PATH; no need to use
+    # LT_CYGPATH in this case.
+    func_to_host_file_result=`cygpath -m "$1"`
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_cygwin_to_w32
+
+
+# func_convert_file_nix_to_w32 ARG
+# Convert file name ARG from *nix to w32 format.  Requires a wine environment
+# and a working winepath. Returns result in func_to_host_file_result.
+func_convert_file_nix_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    func_convert_core_file_wine_to_w32 "$1"
+    func_to_host_file_result=$func_convert_core_file_wine_to_w32_result
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_nix_to_w32
+
+
+# func_convert_file_msys_to_cygwin ARG
+# Convert file name ARG from MSYS to Cygwin format.  Requires LT_CYGPATH set.
+# Returns result in func_to_host_file_result.
+func_convert_file_msys_to_cygwin ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    func_convert_core_msys_to_w32 "$1"
+    func_cygpath -u "$func_convert_core_msys_to_w32_result"
+    func_to_host_file_result=$func_cygpath_result
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_msys_to_cygwin
+
+
+# func_convert_file_nix_to_cygwin ARG
+# Convert file name ARG from *nix to Cygwin format.  Requires Cygwin installed
+# in a wine environment, working winepath, and LT_CYGPATH set.  Returns result
+# in func_to_host_file_result.
+func_convert_file_nix_to_cygwin ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    # convert from *nix to w32, then use cygpath to convert from w32 to cygwin.
+    func_convert_core_file_wine_to_w32 "$1"
+    func_cygpath -u "$func_convert_core_file_wine_to_w32_result"
+    func_to_host_file_result=$func_cygpath_result
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_nix_to_cygwin
+
+
+#############################################
+# $build to $host PATH CONVERSION FUNCTIONS #
+#############################################
+# invoked via '$to_host_path_cmd ARG'
+#
+# In each case, ARG is the path to be converted from $build to $host format.
+# The result will be available in $func_to_host_path_result.
+#
+# Path separators are also converted from $build format to $host format.  If
+# ARG begins or ends with a path separator character, it is preserved (but
+# converted to $host format) on output.
+#
+# All path conversion functions are named using the following convention:
+#   file name conversion function    : func_convert_file_X_to_Y ()
+#   path conversion function         : func_convert_path_X_to_Y ()
+# where, for any given $build/$host combination the 'X_to_Y' value is the
+# same.  If conversion functions are added for new $build/$host combinations,
+# the two new functions must follow this pattern, or func_init_to_host_path_cmd
+# will break.
+
+
+# func_init_to_host_path_cmd
+# Ensures that function "pointer" variable $to_host_path_cmd is set to the
+# appropriate value, based on the value of $to_host_file_cmd.
+to_host_path_cmd=
+func_init_to_host_path_cmd ()
+{
+  $debug_cmd
+
+  if test -z "$to_host_path_cmd"; then
+    func_stripname 'func_convert_file_' '' "$to_host_file_cmd"
+    to_host_path_cmd=func_convert_path_$func_stripname_result
+  fi
+}
+
+
+# func_to_host_path ARG
+# Converts the path ARG from $build format to $host format. Return result
+# in func_to_host_path_result.
+func_to_host_path ()
+{
+  $debug_cmd
+
+  func_init_to_host_path_cmd
+  $to_host_path_cmd "$1"
+}
+# end func_to_host_path
+
+
+# func_convert_path_noop ARG
+# Copy ARG to func_to_host_path_result.
+func_convert_path_noop ()
+{
+  func_to_host_path_result=$1
+}
+# end func_convert_path_noop
+
+
+# func_convert_path_msys_to_w32 ARG
+# Convert path ARG from (mingw) MSYS to (mingw) w32 format; automatic
+# conversion to w32 is not available inside the cwrapper.  Returns result in
+# func_to_host_path_result.
+func_convert_path_msys_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # Remove leading and trailing path separator characters from ARG.  MSYS
+    # behavior is inconsistent here; cygpath turns them into '.;' and ';.';
+    # and winepath ignores them completely.
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_convert_core_msys_to_w32 "$func_to_host_path_tmp1"
+    func_to_host_path_result=$func_convert_core_msys_to_w32_result
+    func_convert_path_check : ";" \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" ";" "$1"
+  fi
+}
+# end func_convert_path_msys_to_w32
+
+
+# func_convert_path_cygwin_to_w32 ARG
+# Convert path ARG from Cygwin to w32 format.  Returns result in
+# func_to_host_file_result.
+func_convert_path_cygwin_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # See func_convert_path_msys_to_w32:
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_to_host_path_result=`cygpath -m -p "$func_to_host_path_tmp1"`
+    func_convert_path_check : ";" \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" ";" "$1"
+  fi
+}
+# end func_convert_path_cygwin_to_w32
+
+
+# func_convert_path_nix_to_w32 ARG
+# Convert path ARG from *nix to w32 format.  Requires a wine environment and
+# a working winepath.  Returns result in func_to_host_file_result.
+func_convert_path_nix_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # See func_convert_path_msys_to_w32:
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_convert_core_path_wine_to_w32 "$func_to_host_path_tmp1"
+    func_to_host_path_result=$func_convert_core_path_wine_to_w32_result
+    func_convert_path_check : ";" \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" ";" "$1"
+  fi
+}
+# end func_convert_path_nix_to_w32
+
+
+# func_convert_path_msys_to_cygwin ARG
+# Convert path ARG from MSYS to Cygwin format.  Requires LT_CYGPATH set.
+# Returns result in func_to_host_file_result.
+func_convert_path_msys_to_cygwin ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # See func_convert_path_msys_to_w32:
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_convert_core_msys_to_w32 "$func_to_host_path_tmp1"
+    func_cygpath -u -p "$func_convert_core_msys_to_w32_result"
+    func_to_host_path_result=$func_cygpath_result
+    func_convert_path_check : : \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" : "$1"
+  fi
+}
+# end func_convert_path_msys_to_cygwin
+
+
+# func_convert_path_nix_to_cygwin ARG
+# Convert path ARG from *nix to Cygwin format.  Requires Cygwin installed in a
+# a wine environment, working winepath, and LT_CYGPATH set.  Returns result in
+# func_to_host_file_result.
+func_convert_path_nix_to_cygwin ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # Remove leading and trailing path separator characters from
+    # ARG. msys behavior is inconsistent here, cygpath turns them
+    # into '.;' and ';.', and winepath ignores them completely.
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_convert_core_path_wine_to_w32 "$func_to_host_path_tmp1"
+    func_cygpath -u -p "$func_convert_core_path_wine_to_w32_result"
+    func_to_host_path_result=$func_cygpath_result
+    func_convert_path_check : : \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" : "$1"
+  fi
+}
+# end func_convert_path_nix_to_cygwin
+
+
+# func_dll_def_p FILE
+# True iff FILE is a Windows DLL '.def' file.
+# Keep in sync with _LT_DLL_DEF_P in libtool.m4
+func_dll_def_p ()
+{
+  $debug_cmd
+
+  func_dll_def_p_tmp=`$SED -n \
+    -e 's/^[	 ]*//' \
+    -e '/^\(;.*\)*$/d' \
+    -e 's/^\(EXPORTS\|LIBRARY\)\([	 ].*\)*$/DEF/p' \
+    -e q \
+    "$1"`
+  test DEF = "$func_dll_def_p_tmp"
+}
+
+
+# func_mode_compile arg...
+func_mode_compile ()
+{
+    $debug_cmd
+
+    # Get the compilation command and the source file.
+    base_compile=
+    srcfile=$nonopt  #  always keep a non-empty value in "srcfile"
+    suppress_opt=yes
+    suppress_output=
+    arg_mode=normal
+    libobj=
+    later=
+    pie_flag=
+
+    for arg
+    do
+      case $arg_mode in
+      arg  )
+	# do not "continue".  Instead, add this to base_compile
+	lastarg=$arg
+	arg_mode=normal
+	;;
+
+      target )
+	libobj=$arg
+	arg_mode=normal
+	continue
+	;;
+
+      normal )
+	# Accept any command-line options.
+	case $arg in
+	-o)
+	  test -n "$libobj" && \
+	    func_fatal_error "you cannot specify '-o' more than once"
+	  arg_mode=target
+	  continue
+	  ;;
+
+	-pie | -fpie | -fPIE)
+          func_append pie_flag " $arg"
+	  continue
+	  ;;
+
+	-shared | -static | -prefer-pic | -prefer-non-pic)
+	  func_append later " $arg"
+	  continue
+	  ;;
+
+	-no-suppress)
+	  suppress_opt=no
+	  continue
+	  ;;
+
+	-Xcompiler)
+	  arg_mode=arg  #  the next one goes into the "base_compile" arg list
+	  continue      #  The current "srcfile" will either be retained or
+	  ;;            #  replaced later.  I would guess that would be a bug.
+
+	-Wc,*)
+	  func_stripname '-Wc,' '' "$arg"
+	  args=$func_stripname_result
+	  lastarg=
+	  save_ifs=$IFS; IFS=,
+	  for arg in $args; do
+	    IFS=$save_ifs
+	    func_append_quoted lastarg "$arg"
+	  done
+	  IFS=$save_ifs
+	  func_stripname ' ' '' "$lastarg"
+	  lastarg=$func_stripname_result
+
+	  # Add the arguments to base_compile.
+	  func_append base_compile " $lastarg"
+	  continue
+	  ;;
+
+	*)
+	  # Accept the current argument as the source file.
+	  # The previous "srcfile" becomes the current argument.
+	  #
+	  lastarg=$srcfile
+	  srcfile=$arg
+	  ;;
+	esac  #  case $arg
+	;;
+      esac    #  case $arg_mode
+
+      # Aesthetically quote the previous argument.
+      func_append_quoted base_compile "$lastarg"
+    done # for arg
+
+    case $arg_mode in
+    arg)
+      func_fatal_error "you must specify an argument for -Xcompile"
+      ;;
+    target)
+      func_fatal_error "you must specify a target with '-o'"
+      ;;
+    *)
+      # Get the name of the library object.
+      test -z "$libobj" && {
+	func_basename "$srcfile"
+	libobj=$func_basename_result
+      }
+      ;;
+    esac
+
+    # Recognize several different file suffixes.
+    # If the user specifies -o file.o, it is replaced with file.lo
+    case $libobj in
+    *.[cCFSifmso] | \
+    *.ada | *.adb | *.ads | *.asm | \
+    *.c++ | *.cc | *.ii | *.class | *.cpp | *.cxx | \
+    *.[fF][09]? | *.for | *.java | *.go | *.obj | *.sx | *.cu | *.cup)
+      func_xform "$libobj"
+      libobj=$func_xform_result
+      ;;
+    esac
+
+    case $libobj in
+    *.lo) func_lo2o "$libobj"; obj=$func_lo2o_result ;;
+    *)
+      func_fatal_error "cannot determine name of library object from '$libobj'"
+      ;;
+    esac
+
+    func_infer_tag $base_compile
+
+    for arg in $later; do
+      case $arg in
+      -shared)
+	test yes = "$build_libtool_libs" \
+	  || func_fatal_configuration "cannot build a shared library"
+	build_old_libs=no
+	continue
+	;;
+
+      -static)
+	build_libtool_libs=no
+	build_old_libs=yes
+	continue
+	;;
+
+      -prefer-pic)
+	pic_mode=yes
+	continue
+	;;
+
+      -prefer-non-pic)
+	pic_mode=no
+	continue
+	;;
+      esac
+    done
+
+    func_quote_for_eval "$libobj"
+    test "X$libobj" != "X$func_quote_for_eval_result" \
+      && $ECHO "X$libobj" | $GREP '[]~#^*{};<>?"'"'"'	 &()|`$[]' \
+      && func_warning "libobj name '$libobj' may not contain shell special characters."
+    func_dirname_and_basename "$obj" "/" ""
+    objname=$func_basename_result
+    xdir=$func_dirname_result
+    lobj=$xdir$objdir/$objname
+
+    test -z "$base_compile" && \
+      func_fatal_help "you must specify a compilation command"
+
+    # Delete any leftover library objects.
+    if test yes = "$build_old_libs"; then
+      removelist="$obj $lobj $libobj ${libobj}T"
+    else
+      removelist="$lobj $libobj ${libobj}T"
+    fi
+
+    # On Cygwin there's no "real" PIC flag so we must build both object types
+    case $host_os in
+    cygwin* | mingw* | pw32* | os2* | cegcc*)
+      pic_mode=default
+      ;;
+    esac
+    if test no = "$pic_mode" && test pass_all != "$deplibs_check_method"; then
+      # non-PIC code in shared libraries is not supported
+      pic_mode=default
+    fi
+
+    # Calculate the filename of the output object if compiler does
+    # not support -o with -c
+    if test no = "$compiler_c_o"; then
+      output_obj=`$ECHO "$srcfile" | $SED 's%^.*/%%; s%\.[^.]*$%%'`.$objext
+      lockfile=$output_obj.lock
+    else
+      output_obj=
+      need_locks=no
+      lockfile=
+    fi
+
+    # Lock this critical section if it is needed
+    # We use this script file to make the link, it avoids creating a new file
+    if test yes = "$need_locks"; then
+      until $opt_dry_run || ln "$progpath" "$lockfile" 2>/dev/null; do
+	func_echo "Waiting for $lockfile to be removed"
+	sleep 2
+      done
+    elif test warn = "$need_locks"; then
+      if test -f "$lockfile"; then
+	$ECHO "\
+*** ERROR, $lockfile exists and contains:
+`cat $lockfile 2>/dev/null`
+
+This indicates that another process is trying to use the same
+temporary object file, and libtool could not work around it because
+your compiler does not support '-c' and '-o' together.  If you
+repeat this compilation, it may succeed, by chance, but you had better
+avoid parallel builds (make -j) in this platform, or get a better
+compiler."
+
+	$opt_dry_run || $RM $removelist
+	exit $EXIT_FAILURE
+      fi
+      func_append removelist " $output_obj"
+      $ECHO "$srcfile" > "$lockfile"
+    fi
+
+    $opt_dry_run || $RM $removelist
+    func_append removelist " $lockfile"
+    trap '$opt_dry_run || $RM $removelist; exit $EXIT_FAILURE' 1 2 15
+
+    func_to_tool_file "$srcfile" func_convert_file_msys_to_w32
+    srcfile=$func_to_tool_file_result
+    func_quote_for_eval "$srcfile"
+    qsrcfile=$func_quote_for_eval_result
+
+    # Only build a PIC object if we are building libtool libraries.
+    if test yes = "$build_libtool_libs"; then
+      # Without this assignment, base_compile gets emptied.
+      fbsd_hideous_sh_bug=$base_compile
+
+      if test no != "$pic_mode"; then
+	command="$base_compile $qsrcfile $pic_flag"
+      else
+	# Don't build PIC code
+	command="$base_compile $qsrcfile"
+      fi
+
+      func_mkdir_p "$xdir$objdir"
+
+      if test -z "$output_obj"; then
+	# Place PIC objects in $objdir
+	func_append command " -o $lobj"
+      fi
+
+      func_show_eval_locale "$command"	\
+          'test -n "$output_obj" && $RM $removelist; exit $EXIT_FAILURE'
+
+      if test warn = "$need_locks" &&
+	 test "X`cat $lockfile 2>/dev/null`" != "X$srcfile"; then
+	$ECHO "\
+*** ERROR, $lockfile contains:
+`cat $lockfile 2>/dev/null`
+
+but it should contain:
+$srcfile
+
+This indicates that another process is trying to use the same
+temporary object file, and libtool could not work around it because
+your compiler does not support '-c' and '-o' together.  If you
+repeat this compilation, it may succeed, by chance, but you had better
+avoid parallel builds (make -j) in this platform, or get a better
+compiler."
+
+	$opt_dry_run || $RM $removelist
+	exit $EXIT_FAILURE
+      fi
+
+      # Just move the object if needed, then go on to compile the next one
+      if test -n "$output_obj" && test "X$output_obj" != "X$lobj"; then
+	func_show_eval '$MV "$output_obj" "$lobj"' \
+	  'error=$?; $opt_dry_run || $RM $removelist; exit $error'
+      fi
+
+      # Allow error messages only from the first compilation.
+      if test yes = "$suppress_opt"; then
+	suppress_output=' >/dev/null 2>&1'
+      fi
+    fi
+
+    # Only build a position-dependent object if we build old libraries.
+    if test yes = "$build_old_libs"; then
+      if test yes != "$pic_mode"; then
+	# Don't build PIC code
+	command="$base_compile $qsrcfile$pie_flag"
+      else
+	command="$base_compile $qsrcfile $pic_flag"
+      fi
+      if test yes = "$compiler_c_o"; then
+	func_append command " -o $obj"
+      fi
+
+      # Suppress compiler output if we already did a PIC compilation.
+      func_append command "$suppress_output"
+      func_show_eval_locale "$command" \
+        '$opt_dry_run || $RM $removelist; exit $EXIT_FAILURE'
+
+      if test warn = "$need_locks" &&
+	 test "X`cat $lockfile 2>/dev/null`" != "X$srcfile"; then
+	$ECHO "\
+*** ERROR, $lockfile contains:
+`cat $lockfile 2>/dev/null`
+
+but it should contain:
+$srcfile
+
+This indicates that another process is trying to use the same
+temporary object file, and libtool could not work around it because
+your compiler does not support '-c' and '-o' together.  If you
+repeat this compilation, it may succeed, by chance, but you had better
+avoid parallel builds (make -j) in this platform, or get a better
+compiler."
+
+	$opt_dry_run || $RM $removelist
+	exit $EXIT_FAILURE
+      fi
+
+      # Just move the object if needed
+      if test -n "$output_obj" && test "X$output_obj" != "X$obj"; then
+	func_show_eval '$MV "$output_obj" "$obj"' \
+	  'error=$?; $opt_dry_run || $RM $removelist; exit $error'
+      fi
+    fi
+
+    $opt_dry_run || {
+      func_write_libtool_object "$libobj" "$objdir/$objname" "$objname"
+
+      # Unlock the critical section if it was locked
+      if test no != "$need_locks"; then
+	removelist=$lockfile
+        $RM "$lockfile"
+      fi
+    }
+
+    exit $EXIT_SUCCESS
+}
+
+$opt_help || {
+  test compile = "$opt_mode" && func_mode_compile ${1+"$@"}
+}
+
+func_mode_help ()
+{
+    # We need to display help for each of the modes.
+    case $opt_mode in
+      "")
+        # Generic help is extracted from the usage comments
+        # at the start of this file.
+        func_help
+        ;;
+
+      clean)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=clean RM [RM-OPTION]... FILE...
+
+Remove files from the build directory.
+
+RM is the name of the program to use to delete files associated with each FILE
+(typically '/bin/rm').  RM-OPTIONS are options (such as '-f') to be passed
+to RM.
+
+If FILE is a libtool library, object or program, all the files associated
+with it are deleted. Otherwise, only FILE itself is deleted using RM."
+        ;;
+
+      compile)
+      $ECHO \
+"Usage: $progname [OPTION]... --mode=compile COMPILE-COMMAND... SOURCEFILE
+
+Compile a source file into a libtool library object.
+
+This mode accepts the following additional options:
+
+  -o OUTPUT-FILE    set the output file name to OUTPUT-FILE
+  -no-suppress      do not suppress compiler output for multiple passes
+  -prefer-pic       try to build PIC objects only
+  -prefer-non-pic   try to build non-PIC objects only
+  -shared           do not build a '.o' file suitable for static linking
+  -static           only build a '.o' file suitable for static linking
+  -Wc,FLAG          pass FLAG directly to the compiler
+
+COMPILE-COMMAND is a command to be used in creating a 'standard' object file
+from the given SOURCEFILE.
+
+The output file name is determined by removing the directory component from
+SOURCEFILE, then substituting the C source code suffix '.c' with the
+library object suffix, '.lo'."
+        ;;
+
+      execute)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=execute COMMAND [ARGS]...
+
+Automatically set library path, then run a program.
+
+This mode accepts the following additional options:
+
+  -dlopen FILE      add the directory containing FILE to the library path
+
+This mode sets the library path environment variable according to '-dlopen'
+flags.
+
+If any of the ARGS are libtool executable wrappers, then they are translated
+into their corresponding uninstalled binary, and any of their required library
+directories are added to the library path.
+
+Then, COMMAND is executed, with ARGS as arguments."
+        ;;
+
+      finish)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=finish [LIBDIR]...
+
+Complete the installation of libtool libraries.
+
+Each LIBDIR is a directory that contains libtool libraries.
+
+The commands that this mode executes may require superuser privileges.  Use
+the '--dry-run' option if you just want to see what would be executed."
+        ;;
+
+      install)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=install INSTALL-COMMAND...
+
+Install executables or libraries.
+
+INSTALL-COMMAND is the installation command.  The first component should be
+either the 'install' or 'cp' program.
+
+The following components of INSTALL-COMMAND are treated specially:
+
+  -inst-prefix-dir PREFIX-DIR  Use PREFIX-DIR as a staging area for installation
+
+The rest of the components are interpreted as arguments to that command (only
+BSD-compatible install options are recognized)."
+        ;;
+
+      link)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=link LINK-COMMAND...
+
+Link object files or libraries together to form another library, or to
+create an executable program.
+
+LINK-COMMAND is a command using the C compiler that you would use to create
+a program from several object files.
+
+The following components of LINK-COMMAND are treated specially:
+
+  -all-static       do not do any dynamic linking at all
+  -avoid-version    do not add a version suffix if possible
+  -bindir BINDIR    specify path to binaries directory (for systems where
+                    libraries must be found in the PATH setting at runtime)
+  -dlopen FILE      '-dlpreopen' FILE if it cannot be dlopened at runtime
+  -dlpreopen FILE   link in FILE and add its symbols to lt_preloaded_symbols
+  -export-dynamic   allow symbols from OUTPUT-FILE to be resolved with dlsym(3)
+  -export-symbols SYMFILE
+                    try to export only the symbols listed in SYMFILE
+  -export-symbols-regex REGEX
+                    try to export only the symbols matching REGEX
+  -LLIBDIR          search LIBDIR for required installed libraries
+  -lNAME            OUTPUT-FILE requires the installed library libNAME
+  -module           build a library that can dlopened
+  -no-fast-install  disable the fast-install mode
+  -no-install       link a not-installable executable
+  -no-undefined     declare that a library does not refer to external symbols
+  -o OUTPUT-FILE    create OUTPUT-FILE from the specified objects
+  -objectlist FILE  use a list of object files found in FILE to specify objects
+  -os2dllname NAME  force a short DLL name on OS/2 (no effect on other OSes)
+  -precious-files-regex REGEX
+                    don't remove output files matching REGEX
+  -release RELEASE  specify package release information
+  -rpath LIBDIR     the created library will eventually be installed in LIBDIR
+  -R[ ]LIBDIR       add LIBDIR to the runtime path of programs and libraries
+  -shared           only do dynamic linking of libtool libraries
+  -shrext SUFFIX    override the standard shared library file extension
+  -static           do not do any dynamic linking of uninstalled libtool libraries
+  -static-libtool-libs
+                    do not do any dynamic linking of libtool libraries
+  -version-info CURRENT[:REVISION[:AGE]]
+                    specify library version info [each variable defaults to 0]
+  -weak LIBNAME     declare that the target provides the LIBNAME interface
+  -Wc,FLAG
+  -Xcompiler FLAG   pass linker-specific FLAG directly to the compiler
+  -Wl,FLAG
+  -Xlinker FLAG     pass linker-specific FLAG directly to the linker
+  -XCClinker FLAG   pass link-specific FLAG to the compiler driver (CC)
+
+All other options (arguments beginning with '-') are ignored.
+
+Every other argument is treated as a filename.  Files ending in '.la' are
+treated as uninstalled libtool libraries, other files are standard or library
+object files.
+
+If the OUTPUT-FILE ends in '.la', then a libtool library is created,
+only library objects ('.lo' files) may be specified, and '-rpath' is
+required, except when creating a convenience library.
+
+If OUTPUT-FILE ends in '.a' or '.lib', then a standard library is created
+using 'ar' and 'ranlib', or on Windows using 'lib'.
+
+If OUTPUT-FILE ends in '.lo' or '.$objext', then a reloadable object file
+is created, otherwise an executable program is created."
+        ;;
+
+      uninstall)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=uninstall RM [RM-OPTION]... FILE...
+
+Remove libraries from an installation directory.
+
+RM is the name of the program to use to delete files associated with each FILE
+(typically '/bin/rm').  RM-OPTIONS are options (such as '-f') to be passed
+to RM.
+
+If FILE is a libtool library, all the files associated with it are deleted.
+Otherwise, only FILE itself is deleted using RM."
+        ;;
+
+      *)
+        func_fatal_help "invalid operation mode '$opt_mode'"
+        ;;
+    esac
+
+    echo
+    $ECHO "Try '$progname --help' for more information about other modes."
+}
+
+# Now that we've collected a possible --mode arg, show help if necessary
+if $opt_help; then
+  if test : = "$opt_help"; then
+    func_mode_help
+  else
+    {
+      func_help noexit
+      for opt_mode in compile link execute install finish uninstall clean; do
+	func_mode_help
+      done
+    } | $SED -n '1p; 2,$s/^Usage:/  or: /p'
+    {
+      func_help noexit
+      for opt_mode in compile link execute install finish uninstall clean; do
+	echo
+	func_mode_help
+      done
+    } |
+    $SED '1d
+      /^When reporting/,/^Report/{
+	H
+	d
+      }
+      $x
+      /information about other modes/d
+      /more detailed .*MODE/d
+      s/^Usage:.*--mode=\([^ ]*\) .*/Description of \1 mode:/'
+  fi
+  exit $?
+fi
+
+
+# func_mode_execute arg...
+func_mode_execute ()
+{
+    $debug_cmd
+
+    # The first argument is the command name.
+    cmd=$nonopt
+    test -z "$cmd" && \
+      func_fatal_help "you must specify a COMMAND"
+
+    # Handle -dlopen flags immediately.
+    for file in $opt_dlopen; do
+      test -f "$file" \
+	|| func_fatal_help "'$file' is not a file"
+
+      dir=
+      case $file in
+      *.la)
+	func_resolve_sysroot "$file"
+	file=$func_resolve_sysroot_result
+
+	# Check to see that this really is a libtool archive.
+	func_lalib_unsafe_p "$file" \
+	  || func_fatal_help "'$lib' is not a valid libtool archive"
+
+	# Read the libtool library.
+	dlname=
+	library_names=
+	func_source "$file"
+
+	# Skip this library if it cannot be dlopened.
+	if test -z "$dlname"; then
+	  # Warn if it was a shared library.
+	  test -n "$library_names" && \
+	    func_warning "'$file' was not linked with '-export-dynamic'"
+	  continue
+	fi
+
+	func_dirname "$file" "" "."
+	dir=$func_dirname_result
+
+	if test -f "$dir/$objdir/$dlname"; then
+	  func_append dir "/$objdir"
+	else
+	  if test ! -f "$dir/$dlname"; then
+	    func_fatal_error "cannot find '$dlname' in '$dir' or '$dir/$objdir'"
+	  fi
+	fi
+	;;
+
+      *.lo)
+	# Just add the directory containing the .lo file.
+	func_dirname "$file" "" "."
+	dir=$func_dirname_result
+	;;
+
+      *)
+	func_warning "'-dlopen' is ignored for non-libtool libraries and objects"
+	continue
+	;;
+      esac
+
+      # Get the absolute pathname.
+      absdir=`cd "$dir" && pwd`
+      test -n "$absdir" && dir=$absdir
+
+      # Now add the directory to shlibpath_var.
+      if eval "test -z \"\$$shlibpath_var\""; then
+	eval "$shlibpath_var=\"\$dir\""
+      else
+	eval "$shlibpath_var=\"\$dir:\$$shlibpath_var\""
+      fi
+    done
+
+    # This variable tells wrapper scripts just to set shlibpath_var
+    # rather than running their programs.
+    libtool_execute_magic=$magic
+
+    # Check if any of the arguments is a wrapper script.
+    args=
+    for file
+    do
+      case $file in
+      -* | *.la | *.lo ) ;;
+      *)
+	# Do a test to see if this is really a libtool program.
+	if func_ltwrapper_script_p "$file"; then
+	  func_source "$file"
+	  # Transform arg to wrapped name.
+	  file=$progdir/$program
+	elif func_ltwrapper_executable_p "$file"; then
+	  func_ltwrapper_scriptname "$file"
+	  func_source "$func_ltwrapper_scriptname_result"
+	  # Transform arg to wrapped name.
+	  file=$progdir/$program
+	fi
+	;;
+      esac
+      # Quote arguments (to preserve shell metacharacters).
+      func_append_quoted args "$file"
+    done
+
+    if $opt_dry_run; then
+      # Display what would be done.
+      if test -n "$shlibpath_var"; then
+	eval "\$ECHO \"\$shlibpath_var=\$$shlibpath_var\""
+	echo "export $shlibpath_var"
+      fi
+      $ECHO "$cmd$args"
+      exit $EXIT_SUCCESS
+    else
+      if test -n "$shlibpath_var"; then
+	# Export the shlibpath_var.
+	eval "export $shlibpath_var"
+      fi
+
+      # Restore saved environment variables
+      for lt_var in LANG LANGUAGE LC_ALL LC_CTYPE LC_COLLATE LC_MESSAGES
+      do
+	eval "if test \"\${save_$lt_var+set}\" = set; then
+                $lt_var=\$save_$lt_var; export $lt_var
+	      else
+		$lt_unset $lt_var
+	      fi"
+      done
+
+      # Now prepare to actually exec the command.
+      exec_cmd=\$cmd$args
+    fi
+}
+
+test execute = "$opt_mode" && func_mode_execute ${1+"$@"}
+
+
+# func_mode_finish arg...
+func_mode_finish ()
+{
+    $debug_cmd
+
+    libs=
+    libdirs=
+    admincmds=
+
+    for opt in "$nonopt" ${1+"$@"}
+    do
+      if test -d "$opt"; then
+	func_append libdirs " $opt"
+
+      elif test -f "$opt"; then
+	if func_lalib_unsafe_p "$opt"; then
+	  func_append libs " $opt"
+	else
+	  func_warning "'$opt' is not a valid libtool archive"
+	fi
+
+      else
+	func_fatal_error "invalid argument '$opt'"
+      fi
+    done
+
+    if test -n "$libs"; then
+      if test -n "$lt_sysroot"; then
+        sysroot_regex=`$ECHO "$lt_sysroot" | $SED "$sed_make_literal_regex"`
+        sysroot_cmd="s/\([ ']\)$sysroot_regex/\1/g;"
+      else
+        sysroot_cmd=
+      fi
+
+      # Remove sysroot references
+      if $opt_dry_run; then
+        for lib in $libs; do
+          echo "removing references to $lt_sysroot and '=' prefixes from $lib"
+        done
+      else
+        tmpdir=`func_mktempdir`
+        for lib in $libs; do
+	  $SED -e "$sysroot_cmd s/\([ ']-[LR]\)=/\1/g; s/\([ ']\)=/\1/g" $lib \
+	    > $tmpdir/tmp-la
+	  mv -f $tmpdir/tmp-la $lib
+	done
+        ${RM}r "$tmpdir"
+      fi
+    fi
+
+    if test -n "$finish_cmds$finish_eval" && test -n "$libdirs"; then
+      for libdir in $libdirs; do
+	if test -n "$finish_cmds"; then
+	  # Do each command in the finish commands.
+	  func_execute_cmds "$finish_cmds" 'admincmds="$admincmds
+'"$cmd"'"'
+	fi
+	if test -n "$finish_eval"; then
+	  # Do the single finish_eval.
+	  eval cmds=\"$finish_eval\"
+	  $opt_dry_run || eval "$cmds" || func_append admincmds "
+       $cmds"
+	fi
+      done
+    fi
+
+    # Exit here if they wanted silent mode.
+    $opt_quiet && exit $EXIT_SUCCESS
+
+    if test -n "$finish_cmds$finish_eval" && test -n "$libdirs"; then
+      echo "----------------------------------------------------------------------"
+      echo "Libraries have been installed in:"
+      for libdir in $libdirs; do
+	$ECHO "   $libdir"
+      done
+      echo
+      echo "If you ever happen to want to link against installed libraries"
+      echo "in a given directory, LIBDIR, you must either use libtool, and"
+      echo "specify the full pathname of the library, or use the '-LLIBDIR'"
+      echo "flag during linking and do at least one of the following:"
+      if test -n "$shlibpath_var"; then
+	echo "   - add LIBDIR to the '$shlibpath_var' environment variable"
+	echo "     during execution"
+      fi
+      if test -n "$runpath_var"; then
+	echo "   - add LIBDIR to the '$runpath_var' environment variable"
+	echo "     during linking"
+      fi
+      if test -n "$hardcode_libdir_flag_spec"; then
+	libdir=LIBDIR
+	eval flag=\"$hardcode_libdir_flag_spec\"
+
+	$ECHO "   - use the '$flag' linker flag"
+      fi
+      if test -n "$admincmds"; then
+	$ECHO "   - have your system administrator run these commands:$admincmds"
+      fi
+      if test -f /etc/ld.so.conf; then
+	echo "   - have your system administrator add LIBDIR to '/etc/ld.so.conf'"
+      fi
+      echo
+
+      echo "See any operating system documentation about shared libraries for"
+      case $host in
+	solaris2.[6789]|solaris2.1[0-9])
+	  echo "more information, such as the ld(1), crle(1) and ld.so(8) manual"
+	  echo "pages."
+	  ;;
+	*)
+	  echo "more information, such as the ld(1) and ld.so(8) manual pages."
+	  ;;
+      esac
+      echo "----------------------------------------------------------------------"
+    fi
+    exit $EXIT_SUCCESS
+}
+
+test finish = "$opt_mode" && func_mode_finish ${1+"$@"}
+
+
+# func_mode_install arg...
+func_mode_install ()
+{
+    $debug_cmd
+
+    # There may be an optional sh(1) argument at the beginning of
+    # install_prog (especially on Windows NT).
+    if test "$SHELL" = "$nonopt" || test /bin/sh = "$nonopt" ||
+       # Allow the use of GNU shtool's install command.
+       case $nonopt in *shtool*) :;; *) false;; esac
+    then
+      # Aesthetically quote it.
+      func_quote_for_eval "$nonopt"
+      install_prog="$func_quote_for_eval_result "
+      arg=$1
+      shift
+    else
+      install_prog=
+      arg=$nonopt
+    fi
+
+    # The real first argument should be the name of the installation program.
+    # Aesthetically quote it.
+    func_quote_for_eval "$arg"
+    func_append install_prog "$func_quote_for_eval_result"
+    install_shared_prog=$install_prog
+    case " $install_prog " in
+      *[\\\ /]cp\ *) install_cp=: ;;
+      *) install_cp=false ;;
+    esac
+
+    # We need to accept at least all the BSD install flags.
+    dest=
+    files=
+    opts=
+    prev=
+    install_type=
+    isdir=false
+    stripme=
+    no_mode=:
+    for arg
+    do
+      arg2=
+      if test -n "$dest"; then
+	func_append files " $dest"
+	dest=$arg
+	continue
+      fi
+
+      case $arg in
+      -d) isdir=: ;;
+      -f)
+	if $install_cp; then :; else
+	  prev=$arg
+	fi
+	;;
+      -g | -m | -o)
+	prev=$arg
+	;;
+      -s)
+	stripme=" -s"
+	continue
+	;;
+      -*)
+	;;
+      *)
+	# If the previous option needed an argument, then skip it.
+	if test -n "$prev"; then
+	  if test X-m = "X$prev" && test -n "$install_override_mode"; then
+	    arg2=$install_override_mode
+	    no_mode=false
+	  fi
+	  prev=
+	else
+	  dest=$arg
+	  continue
+	fi
+	;;
+      esac
+
+      # Aesthetically quote the argument.
+      func_quote_for_eval "$arg"
+      func_append install_prog " $func_quote_for_eval_result"
+      if test -n "$arg2"; then
+	func_quote_for_eval "$arg2"
+      fi
+      func_append install_shared_prog " $func_quote_for_eval_result"
+    done
+
+    test -z "$install_prog" && \
+      func_fatal_help "you must specify an install program"
+
+    test -n "$prev" && \
+      func_fatal_help "the '$prev' option requires an argument"
+
+    if test -n "$install_override_mode" && $no_mode; then
+      if $install_cp; then :; else
+	func_quote_for_eval "$install_override_mode"
+	func_append install_shared_prog " -m $func_quote_for_eval_result"
+      fi
+    fi
+
+    if test -z "$files"; then
+      if test -z "$dest"; then
+	func_fatal_help "no file or destination specified"
+      else
+	func_fatal_help "you must specify a destination"
+      fi
+    fi
+
+    # Strip any trailing slash from the destination.
+    func_stripname '' '/' "$dest"
+    dest=$func_stripname_result
+
+    # Check to see that the destination is a directory.
+    test -d "$dest" && isdir=:
+    if $isdir; then
+      destdir=$dest
+      destname=
+    else
+      func_dirname_and_basename "$dest" "" "."
+      destdir=$func_dirname_result
+      destname=$func_basename_result
+
+      # Not a directory, so check to see that there is only one file specified.
+      set dummy $files; shift
+      test "$#" -gt 1 && \
+	func_fatal_help "'$dest' is not a directory"
+    fi
+    case $destdir in
+    [\\/]* | [A-Za-z]:[\\/]*) ;;
+    *)
+      for file in $files; do
+	case $file in
+	*.lo) ;;
+	*)
+	  func_fatal_help "'$destdir' must be an absolute directory name"
+	  ;;
+	esac
+      done
+      ;;
+    esac
+
+    # This variable tells wrapper scripts just to set variables rather
+    # than running their programs.
+    libtool_install_magic=$magic
+
+    staticlibs=
+    future_libdirs=
+    current_libdirs=
+    for file in $files; do
+
+      # Do each installation.
+      case $file in
+      *.$libext)
+	# Do the static libraries later.
+	func_append staticlibs " $file"
+	;;
+
+      *.la)
+	func_resolve_sysroot "$file"
+	file=$func_resolve_sysroot_result
+
+	# Check to see that this really is a libtool archive.
+	func_lalib_unsafe_p "$file" \
+	  || func_fatal_help "'$file' is not a valid libtool archive"
+
+	library_names=
+	old_library=
+	relink_command=
+	func_source "$file"
+
+	# Add the libdir to current_libdirs if it is the destination.
+	if test "X$destdir" = "X$libdir"; then
+	  case "$current_libdirs " in
+	  *" $libdir "*) ;;
+	  *) func_append current_libdirs " $libdir" ;;
+	  esac
+	else
+	  # Note the libdir as a future libdir.
+	  case "$future_libdirs " in
+	  *" $libdir "*) ;;
+	  *) func_append future_libdirs " $libdir" ;;
+	  esac
+	fi
+
+	func_dirname "$file" "/" ""
+	dir=$func_dirname_result
+	func_append dir "$objdir"
+
+	if test -n "$relink_command"; then
+	  # Determine the prefix the user has applied to our future dir.
+	  inst_prefix_dir=`$ECHO "$destdir" | $SED -e "s%$libdir\$%%"`
+
+	  # Don't allow the user to place us outside of our expected
+	  # location b/c this prevents finding dependent libraries that
+	  # are installed to the same prefix.
+	  # At present, this check doesn't affect windows .dll's that
+	  # are installed into $libdir/../bin (currently, that works fine)
+	  # but it's something to keep an eye on.
+	  test "$inst_prefix_dir" = "$destdir" && \
+	    func_fatal_error "error: cannot install '$file' to a directory not ending in $libdir"
+
+	  if test -n "$inst_prefix_dir"; then
+	    # Stick the inst_prefix_dir data into the link command.
+	    relink_command=`$ECHO "$relink_command" | $SED "s%@inst_prefix_dir@%-inst-prefix-dir $inst_prefix_dir%"`
+	  else
+	    relink_command=`$ECHO "$relink_command" | $SED "s%@inst_prefix_dir@%%"`
+	  fi
+
+	  func_warning "relinking '$file'"
+	  func_show_eval "$relink_command" \
+	    'func_fatal_error "error: relink '\''$file'\'' with the above command before installing it"'
+	fi
+
+	# See the names of the shared library.
+	set dummy $library_names; shift
+	if test -n "$1"; then
+	  realname=$1
+	  shift
+
+	  srcname=$realname
+	  test -n "$relink_command" && srcname=${realname}T
+
+	  # Install the shared library and build the symlinks.
+	  func_show_eval "$install_shared_prog $dir/$srcname $destdir/$realname" \
+	      'exit $?'
+	  tstripme=$stripme
+	  case $host_os in
+	  cygwin* | mingw* | pw32* | cegcc*)
+	    case $realname in
+	    *.dll.a)
+	      tstripme=
+	      ;;
+	    esac
+	    ;;
+	  os2*)
+	    case $realname in
+	    *_dll.a)
+	      tstripme=
+	      ;;
+	    esac
+	    ;;
+	  esac
+	  if test -n "$tstripme" && test -n "$striplib"; then
+	    func_show_eval "$striplib $destdir/$realname" 'exit $?'
+	  fi
+
+	  if test "$#" -gt 0; then
+	    # Delete the old symlinks, and create new ones.
+	    # Try 'ln -sf' first, because the 'ln' binary might depend on
+	    # the symlink we replace!  Solaris /bin/ln does not understand -f,
+	    # so we also need to try rm && ln -s.
+	    for linkname
+	    do
+	      test "$linkname" != "$realname" \
+		&& func_show_eval "(cd $destdir && { $LN_S -f $realname $linkname || { $RM $linkname && $LN_S $realname $linkname; }; })"
+	    done
+	  fi
+
+	  # Do each command in the postinstall commands.
+	  lib=$destdir/$realname
+	  func_execute_cmds "$postinstall_cmds" 'exit $?'
+	fi
+
+	# Install the pseudo-library for information purposes.
+	func_basename "$file"
+	name=$func_basename_result
+	instname=$dir/${name}i
+	func_show_eval "$install_prog $instname $destdir/$name" 'exit $?'
+
+	# Maybe install the static library, too.
+	test -n "$old_library" && func_append staticlibs " $dir/$old_library"
+	;;
+
+      *.lo)
+	# Install (i.e. copy) a libtool object.
+
+	# Figure out destination file name, if it wasn't already specified.
+	if test -n "$destname"; then
+	  destfile=$destdir/$destname
+	else
+	  func_basename "$file"
+	  destfile=$func_basename_result
+	  destfile=$destdir/$destfile
+	fi
+
+	# Deduce the name of the destination old-style object file.
+	case $destfile in
+	*.lo)
+	  func_lo2o "$destfile"
+	  staticdest=$func_lo2o_result
+	  ;;
+	*.$objext)
+	  staticdest=$destfile
+	  destfile=
+	  ;;
+	*)
+	  func_fatal_help "cannot copy a libtool object to '$destfile'"
+	  ;;
+	esac
+
+	# Install the libtool object if requested.
+	test -n "$destfile" && \
+	  func_show_eval "$install_prog $file $destfile" 'exit $?'
+
+	# Install the old object if enabled.
+	if test yes = "$build_old_libs"; then
+	  # Deduce the name of the old-style object file.
+	  func_lo2o "$file"
+	  staticobj=$func_lo2o_result
+	  func_show_eval "$install_prog \$staticobj \$staticdest" 'exit $?'
+	fi
+	exit $EXIT_SUCCESS
+	;;
+
+      *)
+	# Figure out destination file name, if it wasn't already specified.
+	if test -n "$destname"; then
+	  destfile=$destdir/$destname
+	else
+	  func_basename "$file"
+	  destfile=$func_basename_result
+	  destfile=$destdir/$destfile
+	fi
+
+	# If the file is missing, and there is a .exe on the end, strip it
+	# because it is most likely a libtool script we actually want to
+	# install
+	stripped_ext=
+	case $file in
+	  *.exe)
+	    if test ! -f "$file"; then
+	      func_stripname '' '.exe' "$file"
+	      file=$func_stripname_result
+	      stripped_ext=.exe
+	    fi
+	    ;;
+	esac
+
+	# Do a test to see if this is really a libtool program.
+	case $host in
+	*cygwin* | *mingw*)
+	    if func_ltwrapper_executable_p "$file"; then
+	      func_ltwrapper_scriptname "$file"
+	      wrapper=$func_ltwrapper_scriptname_result
+	    else
+	      func_stripname '' '.exe' "$file"
+	      wrapper=$func_stripname_result
+	    fi
+	    ;;
+	*)
+	    wrapper=$file
+	    ;;
+	esac
+	if func_ltwrapper_script_p "$wrapper"; then
+	  notinst_deplibs=
+	  relink_command=
+
+	  func_source "$wrapper"
+
+	  # Check the variables that should have been set.
+	  test -z "$generated_by_libtool_version" && \
+	    func_fatal_error "invalid libtool wrapper script '$wrapper'"
+
+	  finalize=:
+	  for lib in $notinst_deplibs; do
+	    # Check to see that each library is installed.
+	    libdir=
+	    if test -f "$lib"; then
+	      func_source "$lib"
+	    fi
+	    libfile=$libdir/`$ECHO "$lib" | $SED 's%^.*/%%g'`
+	    if test -n "$libdir" && test ! -f "$libfile"; then
+	      func_warning "'$lib' has not been installed in '$libdir'"
+	      finalize=false
+	    fi
+	  done
+
+	  relink_command=
+	  func_source "$wrapper"
+
+	  outputname=
+	  if test no = "$fast_install" && test -n "$relink_command"; then
+	    $opt_dry_run || {
+	      if $finalize; then
+	        tmpdir=`func_mktempdir`
+		func_basename "$file$stripped_ext"
+		file=$func_basename_result
+	        outputname=$tmpdir/$file
+	        # Replace the output file specification.
+	        relink_command=`$ECHO "$relink_command" | $SED 's%@OUTPUT@%'"$outputname"'%g'`
+
+	        $opt_quiet || {
+	          func_quote_for_expand "$relink_command"
+		  eval "func_echo $func_quote_for_expand_result"
+	        }
+	        if eval "$relink_command"; then :
+	          else
+		  func_error "error: relink '$file' with the above command before installing it"
+		  $opt_dry_run || ${RM}r "$tmpdir"
+		  continue
+	        fi
+	        file=$outputname
+	      else
+	        func_warning "cannot relink '$file'"
+	      fi
+	    }
+	  else
+	    # Install the binary that we compiled earlier.
+	    file=`$ECHO "$file$stripped_ext" | $SED "s%\([^/]*\)$%$objdir/\1%"`
+	  fi
+	fi
+
+	# remove .exe since cygwin /usr/bin/install will append another
+	# one anyway
+	case $install_prog,$host in
+	*/usr/bin/install*,*cygwin*)
+	  case $file:$destfile in
+	  *.exe:*.exe)
+	    # this is ok
+	    ;;
+	  *.exe:*)
+	    destfile=$destfile.exe
+	    ;;
+	  *:*.exe)
+	    func_stripname '' '.exe' "$destfile"
+	    destfile=$func_stripname_result
+	    ;;
+	  esac
+	  ;;
+	esac
+	func_show_eval "$install_prog\$stripme \$file \$destfile" 'exit $?'
+	$opt_dry_run || if test -n "$outputname"; then
+	  ${RM}r "$tmpdir"
+	fi
+	;;
+      esac
+    done
+
+    for file in $staticlibs; do
+      func_basename "$file"
+      name=$func_basename_result
+
+      # Set up the ranlib parameters.
+      oldlib=$destdir/$name
+      func_to_tool_file "$oldlib" func_convert_file_msys_to_w32
+      tool_oldlib=$func_to_tool_file_result
+
+      func_show_eval "$install_prog \$file \$oldlib" 'exit $?'
+
+      if test -n "$stripme" && test -n "$old_striplib"; then
+	func_show_eval "$old_striplib $tool_oldlib" 'exit $?'
+      fi
+
+      # Do each command in the postinstall commands.
+      func_execute_cmds "$old_postinstall_cmds" 'exit $?'
+    done
+
+    test -n "$future_libdirs" && \
+      func_warning "remember to run '$progname --finish$future_libdirs'"
+
+    if test -n "$current_libdirs"; then
+      # Maybe just do a dry run.
+      $opt_dry_run && current_libdirs=" -n$current_libdirs"
+      exec_cmd='$SHELL "$progpath" $preserve_args --finish$current_libdirs'
+    else
+      exit $EXIT_SUCCESS
+    fi
+}
+
+test install = "$opt_mode" && func_mode_install ${1+"$@"}
+
+
+# func_generate_dlsyms outputname originator pic_p
+# Extract symbols from dlprefiles and create ${outputname}S.o with
+# a dlpreopen symbol table.
+func_generate_dlsyms ()
+{
+    $debug_cmd
+
+    my_outputname=$1
+    my_originator=$2
+    my_pic_p=${3-false}
+    my_prefix=`$ECHO "$my_originator" | $SED 's%[^a-zA-Z0-9]%_%g'`
+    my_dlsyms=
+
+    if test -n "$dlfiles$dlprefiles" || test no != "$dlself"; then
+      if test -n "$NM" && test -n "$global_symbol_pipe"; then
+	my_dlsyms=${my_outputname}S.c
+      else
+	func_error "not configured to extract global symbols from dlpreopened files"
+      fi
+    fi
+
+    if test -n "$my_dlsyms"; then
+      case $my_dlsyms in
+      "") ;;
+      *.c)
+	# Discover the nlist of each of the dlfiles.
+	nlist=$output_objdir/$my_outputname.nm
+
+	func_show_eval "$RM $nlist ${nlist}S ${nlist}T"
+
+	# Parse the name list into a source file.
+	func_verbose "creating $output_objdir/$my_dlsyms"
+
+	$opt_dry_run || $ECHO > "$output_objdir/$my_dlsyms" "\
+/* $my_dlsyms - symbol resolution table for '$my_outputname' dlsym emulation. */
+/* Generated by $PROGRAM (GNU $PACKAGE) $VERSION */
+
+#ifdef __cplusplus
+extern \"C\" {
+#endif
+
+#if defined __GNUC__ && (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 4)) || (__GNUC__ > 4))
+#pragma GCC diagnostic ignored \"-Wstrict-prototypes\"
+#endif
+
+/* Keep this code in sync between libtool.m4, ltmain, lt_system.h, and tests.  */
+#if defined _WIN32 || defined __CYGWIN__ || defined _WIN32_WCE
+/* DATA imports from DLLs on WIN32 can't be const, because runtime
+   relocations are performed -- see ld's documentation on pseudo-relocs.  */
+# define LT_DLSYM_CONST
+#elif defined __osf__
+/* This system does not cope well with relocations in const data.  */
+# define LT_DLSYM_CONST
+#else
+# define LT_DLSYM_CONST const
+#endif
+
+#define STREQ(s1, s2) (strcmp ((s1), (s2)) == 0)
+
+/* External symbol declarations for the compiler. */\
+"
+
+	if test yes = "$dlself"; then
+	  func_verbose "generating symbol list for '$output'"
+
+	  $opt_dry_run || echo ': @PROGRAM@ ' > "$nlist"
+
+	  # Add our own program objects to the symbol list.
+	  progfiles=`$ECHO "$objs$old_deplibs" | $SP2NL | $SED "$lo2o" | $NL2SP`
+	  for progfile in $progfiles; do
+	    func_to_tool_file "$progfile" func_convert_file_msys_to_w32
+	    func_verbose "extracting global C symbols from '$func_to_tool_file_result'"
+	    $opt_dry_run || eval "$NM $func_to_tool_file_result | $global_symbol_pipe >> '$nlist'"
+	  done
+
+	  if test -n "$exclude_expsyms"; then
+	    $opt_dry_run || {
+	      eval '$EGREP -v " ($exclude_expsyms)$" "$nlist" > "$nlist"T'
+	      eval '$MV "$nlist"T "$nlist"'
+	    }
+	  fi
+
+	  if test -n "$export_symbols_regex"; then
+	    $opt_dry_run || {
+	      eval '$EGREP -e "$export_symbols_regex" "$nlist" > "$nlist"T'
+	      eval '$MV "$nlist"T "$nlist"'
+	    }
+	  fi
+
+	  # Prepare the list of exported symbols
+	  if test -z "$export_symbols"; then
+	    export_symbols=$output_objdir/$outputname.exp
+	    $opt_dry_run || {
+	      $RM $export_symbols
+	      eval "$SED -n -e '/^: @PROGRAM@ $/d' -e 's/^.* \(.*\)$/\1/p' "'< "$nlist" > "$export_symbols"'
+	      case $host in
+	      *cygwin* | *mingw* | *cegcc* )
+                eval "echo EXPORTS "'> "$output_objdir/$outputname.def"'
+                eval 'cat "$export_symbols" >> "$output_objdir/$outputname.def"'
+	        ;;
+	      esac
+	    }
+	  else
+	    $opt_dry_run || {
+	      eval "$SED -e 's/\([].[*^$]\)/\\\\\1/g' -e 's/^/ /' -e 's/$/$/'"' < "$export_symbols" > "$output_objdir/$outputname.exp"'
+	      eval '$GREP -f "$output_objdir/$outputname.exp" < "$nlist" > "$nlist"T'
+	      eval '$MV "$nlist"T "$nlist"'
+	      case $host in
+	        *cygwin* | *mingw* | *cegcc* )
+	          eval "echo EXPORTS "'> "$output_objdir/$outputname.def"'
+	          eval 'cat "$nlist" >> "$output_objdir/$outputname.def"'
+	          ;;
+	      esac
+	    }
+	  fi
+	fi
+
+	for dlprefile in $dlprefiles; do
+	  func_verbose "extracting global C symbols from '$dlprefile'"
+	  func_basename "$dlprefile"
+	  name=$func_basename_result
+          case $host in
+	    *cygwin* | *mingw* | *cegcc* )
+	      # if an import library, we need to obtain dlname
+	      if func_win32_import_lib_p "$dlprefile"; then
+	        func_tr_sh "$dlprefile"
+	        eval "curr_lafile=\$libfile_$func_tr_sh_result"
+	        dlprefile_dlbasename=
+	        if test -n "$curr_lafile" && func_lalib_p "$curr_lafile"; then
+	          # Use subshell, to avoid clobbering current variable values
+	          dlprefile_dlname=`source "$curr_lafile" && echo "$dlname"`
+	          if test -n "$dlprefile_dlname"; then
+	            func_basename "$dlprefile_dlname"
+	            dlprefile_dlbasename=$func_basename_result
+	          else
+	            # no lafile. user explicitly requested -dlpreopen <import library>.
+	            $sharedlib_from_linklib_cmd "$dlprefile"
+	            dlprefile_dlbasename=$sharedlib_from_linklib_result
+	          fi
+	        fi
+	        $opt_dry_run || {
+	          if test -n "$dlprefile_dlbasename"; then
+	            eval '$ECHO ": $dlprefile_dlbasename" >> "$nlist"'
+	          else
+	            func_warning "Could not compute DLL name from $name"
+	            eval '$ECHO ": $name " >> "$nlist"'
+	          fi
+	          func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
+	          eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe |
+	            $SED -e '/I __imp/d' -e 's/I __nm_/D /;s/_nm__//' >> '$nlist'"
+	        }
+	      else # not an import lib
+	        $opt_dry_run || {
+	          eval '$ECHO ": $name " >> "$nlist"'
+	          func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
+	          eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe >> '$nlist'"
+	        }
+	      fi
+	    ;;
+	    *)
+	      $opt_dry_run || {
+	        eval '$ECHO ": $name " >> "$nlist"'
+	        func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
+	        eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe >> '$nlist'"
+	      }
+	    ;;
+          esac
+	done
+
+	$opt_dry_run || {
+	  # Make sure we have at least an empty file.
+	  test -f "$nlist" || : > "$nlist"
+
+	  if test -n "$exclude_expsyms"; then
+	    $EGREP -v " ($exclude_expsyms)$" "$nlist" > "$nlist"T
+	    $MV "$nlist"T "$nlist"
+	  fi
+
+	  # Try sorting and uniquifying the output.
+	  if $GREP -v "^: " < "$nlist" |
+	      if sort -k 3 </dev/null >/dev/null 2>&1; then
+		sort -k 3
+	      else
+		sort +2
+	      fi |
+	      uniq > "$nlist"S; then
+	    :
+	  else
+	    $GREP -v "^: " < "$nlist" > "$nlist"S
+	  fi
+
+	  if test -f "$nlist"S; then
+	    eval "$global_symbol_to_cdecl"' < "$nlist"S >> "$output_objdir/$my_dlsyms"'
+	  else
+	    echo '/* NONE */' >> "$output_objdir/$my_dlsyms"
+	  fi
+
+	  func_show_eval '$RM "${nlist}I"'
+	  if test -n "$global_symbol_to_import"; then
+	    eval "$global_symbol_to_import"' < "$nlist"S > "$nlist"I'
+	  fi
+
+	  echo >> "$output_objdir/$my_dlsyms" "\
+
+/* The mapping between symbol names and symbols.  */
+typedef struct {
+  const char *name;
+  void *address;
+} lt_dlsymlist;
+extern LT_DLSYM_CONST lt_dlsymlist
+lt_${my_prefix}_LTX_preloaded_symbols[];\
+"
+
+	  if test -s "$nlist"I; then
+	    echo >> "$output_objdir/$my_dlsyms" "\
+static void lt_syminit(void)
+{
+  LT_DLSYM_CONST lt_dlsymlist *symbol = lt_${my_prefix}_LTX_preloaded_symbols;
+  for (; symbol->name; ++symbol)
+    {"
+	    $SED 's/.*/      if (STREQ (symbol->name, \"&\")) symbol->address = (void *) \&&;/' < "$nlist"I >> "$output_objdir/$my_dlsyms"
+	    echo >> "$output_objdir/$my_dlsyms" "\
+    }
+}"
+	  fi
+	  echo >> "$output_objdir/$my_dlsyms" "\
+LT_DLSYM_CONST lt_dlsymlist
+lt_${my_prefix}_LTX_preloaded_symbols[] =
+{ {\"$my_originator\", (void *) 0},"
+
+	  if test -s "$nlist"I; then
+	    echo >> "$output_objdir/$my_dlsyms" "\
+  {\"@INIT@\", (void *) &lt_syminit},"
+	  fi
+
+	  case $need_lib_prefix in
+	  no)
+	    eval "$global_symbol_to_c_name_address" < "$nlist" >> "$output_objdir/$my_dlsyms"
+	    ;;
+	  *)
+	    eval "$global_symbol_to_c_name_address_lib_prefix" < "$nlist" >> "$output_objdir/$my_dlsyms"
+	    ;;
+	  esac
+	  echo >> "$output_objdir/$my_dlsyms" "\
+  {0, (void *) 0}
+};
+
+/* This works around a problem in FreeBSD linker */
+#ifdef FREEBSD_WORKAROUND
+static const void *lt_preloaded_setup() {
+  return lt_${my_prefix}_LTX_preloaded_symbols;
+}
+#endif
+
+#ifdef __cplusplus
+}
+#endif\
+"
+	} # !$opt_dry_run
+
+	pic_flag_for_symtable=
+	case "$compile_command " in
+	*" -static "*) ;;
+	*)
+	  case $host in
+	  # compiling the symbol table file with pic_flag works around
+	  # a FreeBSD bug that causes programs to crash when -lm is
+	  # linked before any other PIC object.  But we must not use
+	  # pic_flag when linking with -static.  The problem exists in
+	  # FreeBSD 2.2.6 and is fixed in FreeBSD 3.1.
+	  *-*-freebsd2.*|*-*-freebsd3.0*|*-*-freebsdelf3.0*)
+	    pic_flag_for_symtable=" $pic_flag -DFREEBSD_WORKAROUND" ;;
+	  *-*-hpux*)
+	    pic_flag_for_symtable=" $pic_flag"  ;;
+	  *)
+	    $my_pic_p && pic_flag_for_symtable=" $pic_flag"
+	    ;;
+	  esac
+	  ;;
+	esac
+	symtab_cflags=
+	for arg in $LTCFLAGS; do
+	  case $arg in
+	  -pie | -fpie | -fPIE) ;;
+	  *) func_append symtab_cflags " $arg" ;;
+	  esac
+	done
+
+	# Now compile the dynamic symbol file.
+	func_show_eval '(cd $output_objdir && $LTCC$symtab_cflags -c$no_builtin_flag$pic_flag_for_symtable "$my_dlsyms")' 'exit $?'
+
+	# Clean up the generated files.
+	func_show_eval '$RM "$output_objdir/$my_dlsyms" "$nlist" "${nlist}S" "${nlist}T" "${nlist}I"'
+
+	# Transform the symbol file into the correct name.
+	symfileobj=$output_objdir/${my_outputname}S.$objext
+	case $host in
+	*cygwin* | *mingw* | *cegcc* )
+	  if test -f "$output_objdir/$my_outputname.def"; then
+	    compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$output_objdir/$my_outputname.def $symfileobj%"`
+	    finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$output_objdir/$my_outputname.def $symfileobj%"`
+	  else
+	    compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$symfileobj%"`
+	    finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$symfileobj%"`
+	  fi
+	  ;;
+	*)
+	  compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$symfileobj%"`
+	  finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$symfileobj%"`
+	  ;;
+	esac
+	;;
+      *)
+	func_fatal_error "unknown suffix for '$my_dlsyms'"
+	;;
+      esac
+    else
+      # We keep going just in case the user didn't refer to
+      # lt_preloaded_symbols.  The linker will fail if global_symbol_pipe
+      # really was required.
+
+      # Nullify the symbol file.
+      compile_command=`$ECHO "$compile_command" | $SED "s% @SYMFILE@%%"`
+      finalize_command=`$ECHO "$finalize_command" | $SED "s% @SYMFILE@%%"`
+    fi
+}
+
+# func_cygming_gnu_implib_p ARG
+# This predicate returns with zero status (TRUE) if
+# ARG is a GNU/binutils-style import library. Returns
+# with nonzero status (FALSE) otherwise.
+func_cygming_gnu_implib_p ()
+{
+  $debug_cmd
+
+  func_to_tool_file "$1" func_convert_file_msys_to_w32
+  func_cygming_gnu_implib_tmp=`$NM "$func_to_tool_file_result" | eval "$global_symbol_pipe" | $EGREP ' (_head_[A-Za-z0-9_]+_[ad]l*|[A-Za-z0-9_]+_[ad]l*_iname)$'`
+  test -n "$func_cygming_gnu_implib_tmp"
+}
+
+# func_cygming_ms_implib_p ARG
+# This predicate returns with zero status (TRUE) if
+# ARG is an MS-style import library. Returns
+# with nonzero status (FALSE) otherwise.
+func_cygming_ms_implib_p ()
+{
+  $debug_cmd
+
+  func_to_tool_file "$1" func_convert_file_msys_to_w32
+  func_cygming_ms_implib_tmp=`$NM "$func_to_tool_file_result" | eval "$global_symbol_pipe" | $GREP '_NULL_IMPORT_DESCRIPTOR'`
+  test -n "$func_cygming_ms_implib_tmp"
+}
+
+# func_win32_libid arg
+# return the library type of file 'arg'
+#
+# Need a lot of goo to handle *both* DLLs and import libs
+# Has to be a shell function in order to 'eat' the argument
+# that is supplied when $file_magic_command is called.
+# Despite the name, also deal with 64 bit binaries.
+func_win32_libid ()
+{
+  $debug_cmd
+
+  win32_libid_type=unknown
+  win32_fileres=`file -L $1 2>/dev/null`
+  case $win32_fileres in
+  *ar\ archive\ import\ library*) # definitely import
+    win32_libid_type="x86 archive import"
+    ;;
+  *ar\ archive*) # could be an import, or static
+    # Keep the egrep pattern in sync with the one in _LT_CHECK_MAGIC_METHOD.
+    if eval $OBJDUMP -f $1 | $SED -e '10q' 2>/dev/null |
+       $EGREP 'file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)' >/dev/null; then
+      case $nm_interface in
+      "MS dumpbin")
+	if func_cygming_ms_implib_p "$1" ||
+	   func_cygming_gnu_implib_p "$1"
+	then
+	  win32_nmres=import
+	else
+	  win32_nmres=
+	fi
+	;;
+      *)
+	func_to_tool_file "$1" func_convert_file_msys_to_w32
+	win32_nmres=`eval $NM -f posix -A \"$func_to_tool_file_result\" |
+	  $SED -n -e '
+	    1,100{
+		/ I /{
+		    s|.*|import|
+		    p
+		    q
+		}
+	    }'`
+	;;
+      esac
+      case $win32_nmres in
+      import*)  win32_libid_type="x86 archive import";;
+      *)        win32_libid_type="x86 archive static";;
+      esac
+    fi
+    ;;
+  *DLL*)
+    win32_libid_type="x86 DLL"
+    ;;
+  *executable*) # but shell scripts are "executable" too...
+    case $win32_fileres in
+    *MS\ Windows\ PE\ Intel*)
+      win32_libid_type="x86 DLL"
+      ;;
+    esac
+    ;;
+  esac
+  $ECHO "$win32_libid_type"
+}
+
+# func_cygming_dll_for_implib ARG
+#
+# Platform-specific function to extract the
+# name of the DLL associated with the specified
+# import library ARG.
+# Invoked by eval'ing the libtool variable
+#    $sharedlib_from_linklib_cmd
+# Result is available in the variable
+#    $sharedlib_from_linklib_result
+func_cygming_dll_for_implib ()
+{
+  $debug_cmd
+
+  sharedlib_from_linklib_result=`$DLLTOOL --identify-strict --identify "$1"`
+}
+
+# func_cygming_dll_for_implib_fallback_core SECTION_NAME LIBNAMEs
+#
+# The is the core of a fallback implementation of a
+# platform-specific function to extract the name of the
+# DLL associated with the specified import library LIBNAME.
+#
+# SECTION_NAME is either .idata$6 or .idata$7, depending
+# on the platform and compiler that created the implib.
+#
+# Echos the name of the DLL associated with the
+# specified import library.
+func_cygming_dll_for_implib_fallback_core ()
+{
+  $debug_cmd
+
+  match_literal=`$ECHO "$1" | $SED "$sed_make_literal_regex"`
+  $OBJDUMP -s --section "$1" "$2" 2>/dev/null |
+    $SED '/^Contents of section '"$match_literal"':/{
+      # Place marker at beginning of archive member dllname section
+      s/.*/====MARK====/
+      p
+      d
+    }
+    # These lines can sometimes be longer than 43 characters, but
+    # are always uninteresting
+    /:[	 ]*file format pe[i]\{,1\}-/d
+    /^In archive [^:]*:/d
+    # Ensure marker is printed
+    /^====MARK====/p
+    # Remove all lines with less than 43 characters
+    /^.\{43\}/!d
+    # From remaining lines, remove first 43 characters
+    s/^.\{43\}//' |
+    $SED -n '
+      # Join marker and all lines until next marker into a single line
+      /^====MARK====/ b para
+      H
+      $ b para
+      b
+      :para
+      x
+      s/\n//g
+      # Remove the marker
+      s/^====MARK====//
+      # Remove trailing dots and whitespace
+      s/[\. \t]*$//
+      # Print
+      /./p' |
+    # we now have a list, one entry per line, of the stringified
+    # contents of the appropriate section of all members of the
+    # archive that possess that section. Heuristic: eliminate
+    # all those that have a first or second character that is
+    # a '.' (that is, objdump's representation of an unprintable
+    # character.) This should work for all archives with less than
+    # 0x302f exports -- but will fail for DLLs whose name actually
+    # begins with a literal '.' or a single character followed by
+    # a '.'.
+    #
+    # Of those that remain, print the first one.
+    $SED -e '/^\./d;/^.\./d;q'
+}
+
+# func_cygming_dll_for_implib_fallback ARG
+# Platform-specific function to extract the
+# name of the DLL associated with the specified
+# import library ARG.
+#
+# This fallback implementation is for use when $DLLTOOL
+# does not support the --identify-strict option.
+# Invoked by eval'ing the libtool variable
+#    $sharedlib_from_linklib_cmd
+# Result is available in the variable
+#    $sharedlib_from_linklib_result
+func_cygming_dll_for_implib_fallback ()
+{
+  $debug_cmd
+
+  if func_cygming_gnu_implib_p "$1"; then
+    # binutils import library
+    sharedlib_from_linklib_result=`func_cygming_dll_for_implib_fallback_core '.idata$7' "$1"`
+  elif func_cygming_ms_implib_p "$1"; then
+    # ms-generated import library
+    sharedlib_from_linklib_result=`func_cygming_dll_for_implib_fallback_core '.idata$6' "$1"`
+  else
+    # unknown
+    sharedlib_from_linklib_result=
+  fi
+}
+
+
+# func_extract_an_archive dir oldlib
+func_extract_an_archive ()
+{
+    $debug_cmd
+
+    f_ex_an_ar_dir=$1; shift
+    f_ex_an_ar_oldlib=$1
+    if test yes = "$lock_old_archive_extraction"; then
+      lockfile=$f_ex_an_ar_oldlib.lock
+      until $opt_dry_run || ln "$progpath" "$lockfile" 2>/dev/null; do
+	func_echo "Waiting for $lockfile to be removed"
+	sleep 2
+      done
+    fi
+    func_show_eval "(cd \$f_ex_an_ar_dir && $AR x \"\$f_ex_an_ar_oldlib\")" \
+		   'stat=$?; rm -f "$lockfile"; exit $stat'
+    if test yes = "$lock_old_archive_extraction"; then
+      $opt_dry_run || rm -f "$lockfile"
+    fi
+    if ($AR t "$f_ex_an_ar_oldlib" | sort | sort -uc >/dev/null 2>&1); then
+     :
+    else
+      func_fatal_error "object name conflicts in archive: $f_ex_an_ar_dir/$f_ex_an_ar_oldlib"
+    fi
+}
+
+
+# func_extract_archives gentop oldlib ...
+func_extract_archives ()
+{
+    $debug_cmd
+
+    my_gentop=$1; shift
+    my_oldlibs=${1+"$@"}
+    my_oldobjs=
+    my_xlib=
+    my_xabs=
+    my_xdir=
+
+    for my_xlib in $my_oldlibs; do
+      # Extract the objects.
+      case $my_xlib in
+	[\\/]* | [A-Za-z]:[\\/]*) my_xabs=$my_xlib ;;
+	*) my_xabs=`pwd`"/$my_xlib" ;;
+      esac
+      func_basename "$my_xlib"
+      my_xlib=$func_basename_result
+      my_xlib_u=$my_xlib
+      while :; do
+        case " $extracted_archives " in
+	*" $my_xlib_u "*)
+	  func_arith $extracted_serial + 1
+	  extracted_serial=$func_arith_result
+	  my_xlib_u=lt$extracted_serial-$my_xlib ;;
+	*) break ;;
+	esac
+      done
+      extracted_archives="$extracted_archives $my_xlib_u"
+      my_xdir=$my_gentop/$my_xlib_u
+
+      func_mkdir_p "$my_xdir"
+
+      case $host in
+      *-darwin*)
+	func_verbose "Extracting $my_xabs"
+	# Do not bother doing anything if just a dry run
+	$opt_dry_run || {
+	  darwin_orig_dir=`pwd`
+	  cd $my_xdir || exit $?
+	  darwin_archive=$my_xabs
+	  darwin_curdir=`pwd`
+	  func_basename "$darwin_archive"
+	  darwin_base_archive=$func_basename_result
+	  darwin_arches=`$LIPO -info "$darwin_archive" 2>/dev/null | $GREP Architectures 2>/dev/null || true`
+	  if test -n "$darwin_arches"; then
+	    darwin_arches=`$ECHO "$darwin_arches" | $SED -e 's/.*are://'`
+	    darwin_arch=
+	    func_verbose "$darwin_base_archive has multiple architectures $darwin_arches"
+	    for darwin_arch in  $darwin_arches; do
+	      func_mkdir_p "unfat-$$/$darwin_base_archive-$darwin_arch"
+	      $LIPO -thin $darwin_arch -output "unfat-$$/$darwin_base_archive-$darwin_arch/$darwin_base_archive" "$darwin_archive"
+	      cd "unfat-$$/$darwin_base_archive-$darwin_arch"
+	      func_extract_an_archive "`pwd`" "$darwin_base_archive"
+	      cd "$darwin_curdir"
+	      $RM "unfat-$$/$darwin_base_archive-$darwin_arch/$darwin_base_archive"
+	    done # $darwin_arches
+            ## Okay now we've a bunch of thin objects, gotta fatten them up :)
+	    darwin_filelist=`find unfat-$$ -type f -name \*.o -print -o -name \*.lo -print | $SED -e "$sed_basename" | sort -u`
+	    darwin_file=
+	    darwin_files=
+	    for darwin_file in $darwin_filelist; do
+	      darwin_files=`find unfat-$$ -name $darwin_file -print | sort | $NL2SP`
+	      $LIPO -create -output "$darwin_file" $darwin_files
+	    done # $darwin_filelist
+	    $RM -rf unfat-$$
+	    cd "$darwin_orig_dir"
+	  else
+	    cd $darwin_orig_dir
+	    func_extract_an_archive "$my_xdir" "$my_xabs"
+	  fi # $darwin_arches
+	} # !$opt_dry_run
+	;;
+      *)
+        func_extract_an_archive "$my_xdir" "$my_xabs"
+	;;
+      esac
+      my_oldobjs="$my_oldobjs "`find $my_xdir -name \*.$objext -print -o -name \*.lo -print | sort | $NL2SP`
+    done
+
+    func_extract_archives_result=$my_oldobjs
+}
+
+
+# func_emit_wrapper [arg=no]
+#
+# Emit a libtool wrapper script on stdout.
+# Don't directly open a file because we may want to
+# incorporate the script contents within a cygwin/mingw
+# wrapper executable.  Must ONLY be called from within
+# func_mode_link because it depends on a number of variables
+# set therein.
+#
+# ARG is the value that the WRAPPER_SCRIPT_BELONGS_IN_OBJDIR
+# variable will take.  If 'yes', then the emitted script
+# will assume that the directory where it is stored is
+# the $objdir directory.  This is a cygwin/mingw-specific
+# behavior.
+func_emit_wrapper ()
+{
+	func_emit_wrapper_arg1=${1-no}
+
+	$ECHO "\
+#! $SHELL
+
+# $output - temporary wrapper script for $objdir/$outputname
+# Generated by $PROGRAM (GNU $PACKAGE) $VERSION
+#
+# The $output program cannot be directly executed until all the libtool
+# libraries that it depends on are installed.
+#
+# This wrapper script should never be moved out of the build directory.
+# If it is, it will not operate correctly.
+
+# Sed substitution that helps us do robust quoting.  It backslashifies
+# metacharacters that are still active within double-quoted strings.
+sed_quote_subst='$sed_quote_subst'
+
+# Be Bourne compatible
+if test -n \"\${ZSH_VERSION+set}\" && (emulate sh) >/dev/null 2>&1; then
+  emulate sh
+  NULLCMD=:
+  # Zsh 3.x and 4.x performs word splitting on \${1+\"\$@\"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '\${1+\"\$@\"}'='\"\$@\"'
+  setopt NO_GLOB_SUBST
+else
+  case \`(set -o) 2>/dev/null\` in *posix*) set -o posix;; esac
+fi
+BIN_SH=xpg4; export BIN_SH # for Tru64
+DUALCASE=1; export DUALCASE # for MKS sh
+
+# The HP-UX ksh and POSIX shell print the target directory to stdout
+# if CDPATH is set.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+relink_command=\"$relink_command\"
+
+# This environment variable determines our operation mode.
+if test \"\$libtool_install_magic\" = \"$magic\"; then
+  # install mode needs the following variables:
+  generated_by_libtool_version='$macro_version'
+  notinst_deplibs='$notinst_deplibs'
+else
+  # When we are sourced in execute mode, \$file and \$ECHO are already set.
+  if test \"\$libtool_execute_magic\" != \"$magic\"; then
+    file=\"\$0\""
+
+    qECHO=`$ECHO "$ECHO" | $SED "$sed_quote_subst"`
+    $ECHO "\
+
+# A function that is used when there is no print builtin or printf.
+func_fallback_echo ()
+{
+  eval 'cat <<_LTECHO_EOF
+\$1
+_LTECHO_EOF'
+}
+    ECHO=\"$qECHO\"
+  fi
+
+# Very basic option parsing. These options are (a) specific to
+# the libtool wrapper, (b) are identical between the wrapper
+# /script/ and the wrapper /executable/ that is used only on
+# windows platforms, and (c) all begin with the string "--lt-"
+# (application programs are unlikely to have options that match
+# this pattern).
+#
+# There are only two supported options: --lt-debug and
+# --lt-dump-script. There is, deliberately, no --lt-help.
+#
+# The first argument to this parsing function should be the
+# script's $0 value, followed by "$@".
+lt_option_debug=
+func_parse_lt_options ()
+{
+  lt_script_arg0=\$0
+  shift
+  for lt_opt
+  do
+    case \"\$lt_opt\" in
+    --lt-debug) lt_option_debug=1 ;;
+    --lt-dump-script)
+        lt_dump_D=\`\$ECHO \"X\$lt_script_arg0\" | $SED -e 's/^X//' -e 's%/[^/]*$%%'\`
+        test \"X\$lt_dump_D\" = \"X\$lt_script_arg0\" && lt_dump_D=.
+        lt_dump_F=\`\$ECHO \"X\$lt_script_arg0\" | $SED -e 's/^X//' -e 's%^.*/%%'\`
+        cat \"\$lt_dump_D/\$lt_dump_F\"
+        exit 0
+      ;;
+    --lt-*)
+        \$ECHO \"Unrecognized --lt- option: '\$lt_opt'\" 1>&2
+        exit 1
+      ;;
+    esac
+  done
+
+  # Print the debug banner immediately:
+  if test -n \"\$lt_option_debug\"; then
+    echo \"$outputname:$output:\$LINENO: libtool wrapper (GNU $PACKAGE) $VERSION\" 1>&2
+  fi
+}
+
+# Used when --lt-debug. Prints its arguments to stdout
+# (redirection is the responsibility of the caller)
+func_lt_dump_args ()
+{
+  lt_dump_args_N=1;
+  for lt_arg
+  do
+    \$ECHO \"$outputname:$output:\$LINENO: newargv[\$lt_dump_args_N]: \$lt_arg\"
+    lt_dump_args_N=\`expr \$lt_dump_args_N + 1\`
+  done
+}
+
+# Core function for launching the target application
+func_exec_program_core ()
+{
+"
+  case $host in
+  # Backslashes separate directories on plain windows
+  *-*-mingw | *-*-os2* | *-cegcc*)
+    $ECHO "\
+      if test -n \"\$lt_option_debug\"; then
+        \$ECHO \"$outputname:$output:\$LINENO: newargv[0]: \$progdir\\\\\$program\" 1>&2
+        func_lt_dump_args \${1+\"\$@\"} 1>&2
+      fi
+      exec \"\$progdir\\\\\$program\" \${1+\"\$@\"}
+"
+    ;;
+
+  *)
+    $ECHO "\
+      if test -n \"\$lt_option_debug\"; then
+        \$ECHO \"$outputname:$output:\$LINENO: newargv[0]: \$progdir/\$program\" 1>&2
+        func_lt_dump_args \${1+\"\$@\"} 1>&2
+      fi
+      exec \"\$progdir/\$program\" \${1+\"\$@\"}
+"
+    ;;
+  esac
+  $ECHO "\
+      \$ECHO \"\$0: cannot exec \$program \$*\" 1>&2
+      exit 1
+}
+
+# A function to encapsulate launching the target application
+# Strips options in the --lt-* namespace from \$@ and
+# launches target application with the remaining arguments.
+func_exec_program ()
+{
+  case \" \$* \" in
+  *\\ --lt-*)
+    for lt_wr_arg
+    do
+      case \$lt_wr_arg in
+      --lt-*) ;;
+      *) set x \"\$@\" \"\$lt_wr_arg\"; shift;;
+      esac
+      shift
+    done ;;
+  esac
+  func_exec_program_core \${1+\"\$@\"}
+}
+
+  # Parse options
+  func_parse_lt_options \"\$0\" \${1+\"\$@\"}
+
+  # Find the directory that this script lives in.
+  thisdir=\`\$ECHO \"\$file\" | $SED 's%/[^/]*$%%'\`
+  test \"x\$thisdir\" = \"x\$file\" && thisdir=.
+
+  # Follow symbolic links until we get to the real thisdir.
+  file=\`ls -ld \"\$file\" | $SED -n 's/.*-> //p'\`
+  while test -n \"\$file\"; do
+    destdir=\`\$ECHO \"\$file\" | $SED 's%/[^/]*\$%%'\`
+
+    # If there was a directory component, then change thisdir.
+    if test \"x\$destdir\" != \"x\$file\"; then
+      case \"\$destdir\" in
+      [\\\\/]* | [A-Za-z]:[\\\\/]*) thisdir=\"\$destdir\" ;;
+      *) thisdir=\"\$thisdir/\$destdir\" ;;
+      esac
+    fi
+
+    file=\`\$ECHO \"\$file\" | $SED 's%^.*/%%'\`
+    file=\`ls -ld \"\$thisdir/\$file\" | $SED -n 's/.*-> //p'\`
+  done
+
+  # Usually 'no', except on cygwin/mingw when embedded into
+  # the cwrapper.
+  WRAPPER_SCRIPT_BELONGS_IN_OBJDIR=$func_emit_wrapper_arg1
+  if test \"\$WRAPPER_SCRIPT_BELONGS_IN_OBJDIR\" = \"yes\"; then
+    # special case for '.'
+    if test \"\$thisdir\" = \".\"; then
+      thisdir=\`pwd\`
+    fi
+    # remove .libs from thisdir
+    case \"\$thisdir\" in
+    *[\\\\/]$objdir ) thisdir=\`\$ECHO \"\$thisdir\" | $SED 's%[\\\\/][^\\\\/]*$%%'\` ;;
+    $objdir )   thisdir=. ;;
+    esac
+  fi
+
+  # Try to get the absolute directory name.
+  absdir=\`cd \"\$thisdir\" && pwd\`
+  test -n \"\$absdir\" && thisdir=\"\$absdir\"
+"
+
+	if test yes = "$fast_install"; then
+	  $ECHO "\
+  program=lt-'$outputname'$exeext
+  progdir=\"\$thisdir/$objdir\"
+
+  if test ! -f \"\$progdir/\$program\" ||
+     { file=\`ls -1dt \"\$progdir/\$program\" \"\$progdir/../\$program\" 2>/dev/null | $SED 1q\`; \\
+       test \"X\$file\" != \"X\$progdir/\$program\"; }; then
+
+    file=\"\$\$-\$program\"
+
+    if test ! -d \"\$progdir\"; then
+      $MKDIR \"\$progdir\"
+    else
+      $RM \"\$progdir/\$file\"
+    fi"
+
+	  $ECHO "\
+
+    # relink executable if necessary
+    if test -n \"\$relink_command\"; then
+      if relink_command_output=\`eval \$relink_command 2>&1\`; then :
+      else
+	\$ECHO \"\$relink_command_output\" >&2
+	$RM \"\$progdir/\$file\"
+	exit 1
+      fi
+    fi
+
+    $MV \"\$progdir/\$file\" \"\$progdir/\$program\" 2>/dev/null ||
+    { $RM \"\$progdir/\$program\";
+      $MV \"\$progdir/\$file\" \"\$progdir/\$program\"; }
+    $RM \"\$progdir/\$file\"
+  fi"
+	else
+	  $ECHO "\
+  program='$outputname'
+  progdir=\"\$thisdir/$objdir\"
+"
+	fi
+
+	$ECHO "\
+
+  if test -f \"\$progdir/\$program\"; then"
+
+	# fixup the dll searchpath if we need to.
+	#
+	# Fix the DLL searchpath if we need to.  Do this before prepending
+	# to shlibpath, because on Windows, both are PATH and uninstalled
+	# libraries must come first.
+	if test -n "$dllsearchpath"; then
+	  $ECHO "\
+    # Add the dll search path components to the executable PATH
+    PATH=$dllsearchpath:\$PATH
+"
+	fi
+
+	# Export our shlibpath_var if we have one.
+	if test yes = "$shlibpath_overrides_runpath" && test -n "$shlibpath_var" && test -n "$temp_rpath"; then
+	  $ECHO "\
+    # Add our own library path to $shlibpath_var
+    $shlibpath_var=\"$temp_rpath\$$shlibpath_var\"
+
+    # Some systems cannot cope with colon-terminated $shlibpath_var
+    # The second colon is a workaround for a bug in BeOS R4 sed
+    $shlibpath_var=\`\$ECHO \"\$$shlibpath_var\" | $SED 's/::*\$//'\`
+
+    export $shlibpath_var
+"
+	fi
+
+	$ECHO "\
+    if test \"\$libtool_execute_magic\" != \"$magic\"; then
+      # Run the actual program with our arguments.
+      func_exec_program \${1+\"\$@\"}
+    fi
+  else
+    # The program doesn't exist.
+    \$ECHO \"\$0: error: '\$progdir/\$program' does not exist\" 1>&2
+    \$ECHO \"This script is just a wrapper for \$program.\" 1>&2
+    \$ECHO \"See the $PACKAGE documentation for more information.\" 1>&2
+    exit 1
+  fi
+fi\
+"
+}
+
+
+# func_emit_cwrapperexe_src
+# emit the source code for a wrapper executable on stdout
+# Must ONLY be called from within func_mode_link because
+# it depends on a number of variable set therein.
+func_emit_cwrapperexe_src ()
+{
+	cat <<EOF
+
+/* $cwrappersource - temporary wrapper executable for $objdir/$outputname
+   Generated by $PROGRAM (GNU $PACKAGE) $VERSION
+
+   The $output program cannot be directly executed until all the libtool
+   libraries that it depends on are installed.
+
+   This wrapper executable should never be moved out of the build directory.
+   If it is, it will not operate correctly.
+*/
+EOF
+	    cat <<"EOF"
+#ifdef _MSC_VER
+# define _CRT_SECURE_NO_DEPRECATE 1
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef _MSC_VER
+# include <direct.h>
+# include <process.h>
+# include <io.h>
+#else
+# include <unistd.h>
+# include <stdint.h>
+# ifdef __CYGWIN__
+#  include <io.h>
+# endif
+#endif
+#include <malloc.h>
+#include <stdarg.h>
+#include <assert.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+
+#define STREQ(s1, s2) (strcmp ((s1), (s2)) == 0)
+
+/* declarations of non-ANSI functions */
+#if defined __MINGW32__
+# ifdef __STRICT_ANSI__
+int _putenv (const char *);
+# endif
+#elif defined __CYGWIN__
+# ifdef __STRICT_ANSI__
+char *realpath (const char *, char *);
+int putenv (char *);
+int setenv (const char *, const char *, int);
+# endif
+/* #elif defined other_platform || defined ... */
+#endif
+
+/* portability defines, excluding path handling macros */
+#if defined _MSC_VER
+# define setmode _setmode
+# define stat    _stat
+# define chmod   _chmod
+# define getcwd  _getcwd
+# define putenv  _putenv
+# define S_IXUSR _S_IEXEC
+#elif defined __MINGW32__
+# define setmode _setmode
+# define stat    _stat
+# define chmod   _chmod
+# define getcwd  _getcwd
+# define putenv  _putenv
+#elif defined __CYGWIN__
+# define HAVE_SETENV
+# define FOPEN_WB "wb"
+/* #elif defined other platforms ... */
+#endif
+
+#if defined PATH_MAX
+# define LT_PATHMAX PATH_MAX
+#elif defined MAXPATHLEN
+# define LT_PATHMAX MAXPATHLEN
+#else
+# define LT_PATHMAX 1024
+#endif
+
+#ifndef S_IXOTH
+# define S_IXOTH 0
+#endif
+#ifndef S_IXGRP
+# define S_IXGRP 0
+#endif
+
+/* path handling portability macros */
+#ifndef DIR_SEPARATOR
+# define DIR_SEPARATOR '/'
+# define PATH_SEPARATOR ':'
+#endif
+
+#if defined _WIN32 || defined __MSDOS__ || defined __DJGPP__ || \
+  defined __OS2__
+# define HAVE_DOS_BASED_FILE_SYSTEM
+# define FOPEN_WB "wb"
+# ifndef DIR_SEPARATOR_2
+#  define DIR_SEPARATOR_2 '\\'
+# endif
+# ifndef PATH_SEPARATOR_2
+#  define PATH_SEPARATOR_2 ';'
+# endif
+#endif
+
+#ifndef DIR_SEPARATOR_2
+# define IS_DIR_SEPARATOR(ch) ((ch) == DIR_SEPARATOR)
+#else /* DIR_SEPARATOR_2 */
+# define IS_DIR_SEPARATOR(ch) \
+	(((ch) == DIR_SEPARATOR) || ((ch) == DIR_SEPARATOR_2))
+#endif /* DIR_SEPARATOR_2 */
+
+#ifndef PATH_SEPARATOR_2
+# define IS_PATH_SEPARATOR(ch) ((ch) == PATH_SEPARATOR)
+#else /* PATH_SEPARATOR_2 */
+# define IS_PATH_SEPARATOR(ch) ((ch) == PATH_SEPARATOR_2)
+#endif /* PATH_SEPARATOR_2 */
+
+#ifndef FOPEN_WB
+# define FOPEN_WB "w"
+#endif
+#ifndef _O_BINARY
+# define _O_BINARY 0
+#endif
+
+#define XMALLOC(type, num)      ((type *) xmalloc ((num) * sizeof(type)))
+#define XFREE(stale) do { \
+  if (stale) { free (stale); stale = 0; } \
+} while (0)
+
+#if defined LT_DEBUGWRAPPER
+static int lt_debug = 1;
+#else
+static int lt_debug = 0;
+#endif
+
+const char *program_name = "libtool-wrapper"; /* in case xstrdup fails */
+
+void *xmalloc (size_t num);
+char *xstrdup (const char *string);
+const char *base_name (const char *name);
+char *find_executable (const char *wrapper);
+char *chase_symlinks (const char *pathspec);
+int make_executable (const char *path);
+int check_executable (const char *path);
+char *strendzap (char *str, const char *pat);
+void lt_debugprintf (const char *file, int line, const char *fmt, ...);
+void lt_fatal (const char *file, int line, const char *message, ...);
+static const char *nonnull (const char *s);
+static const char *nonempty (const char *s);
+void lt_setenv (const char *name, const char *value);
+char *lt_extend_str (const char *orig_value, const char *add, int to_end);
+void lt_update_exe_path (const char *name, const char *value);
+void lt_update_lib_path (const char *name, const char *value);
+char **prepare_spawn (char **argv);
+void lt_dump_script (FILE *f);
+EOF
+
+	    cat <<EOF
+#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 5)
+# define externally_visible volatile
+#else
+# define externally_visible __attribute__((externally_visible)) volatile
+#endif
+externally_visible const char * MAGIC_EXE = "$magic_exe";
+const char * LIB_PATH_VARNAME = "$shlibpath_var";
+EOF
+
+	    if test yes = "$shlibpath_overrides_runpath" && test -n "$shlibpath_var" && test -n "$temp_rpath"; then
+              func_to_host_path "$temp_rpath"
+	      cat <<EOF
+const char * LIB_PATH_VALUE   = "$func_to_host_path_result";
+EOF
+	    else
+	      cat <<"EOF"
+const char * LIB_PATH_VALUE   = "";
+EOF
+	    fi
+
+	    if test -n "$dllsearchpath"; then
+              func_to_host_path "$dllsearchpath:"
+	      cat <<EOF
+const char * EXE_PATH_VARNAME = "PATH";
+const char * EXE_PATH_VALUE   = "$func_to_host_path_result";
+EOF
+	    else
+	      cat <<"EOF"
+const char * EXE_PATH_VARNAME = "";
+const char * EXE_PATH_VALUE   = "";
+EOF
+	    fi
+
+	    if test yes = "$fast_install"; then
+	      cat <<EOF
+const char * TARGET_PROGRAM_NAME = "lt-$outputname"; /* hopefully, no .exe */
+EOF
+	    else
+	      cat <<EOF
+const char * TARGET_PROGRAM_NAME = "$outputname"; /* hopefully, no .exe */
+EOF
+	    fi
+
+
+	    cat <<"EOF"
+
+#define LTWRAPPER_OPTION_PREFIX         "--lt-"
+
+static const char *ltwrapper_option_prefix = LTWRAPPER_OPTION_PREFIX;
+static const char *dumpscript_opt       = LTWRAPPER_OPTION_PREFIX "dump-script";
+static const char *debug_opt            = LTWRAPPER_OPTION_PREFIX "debug";
+
+int
+main (int argc, char *argv[])
+{
+  char **newargz;
+  int  newargc;
+  char *tmp_pathspec;
+  char *actual_cwrapper_path;
+  char *actual_cwrapper_name;
+  char *target_name;
+  char *lt_argv_zero;
+  int rval = 127;
+
+  int i;
+
+  program_name = (char *) xstrdup (base_name (argv[0]));
+  newargz = XMALLOC (char *, (size_t) argc + 1);
+
+  /* very simple arg parsing; don't want to rely on getopt
+   * also, copy all non cwrapper options to newargz, except
+   * argz[0], which is handled differently
+   */
+  newargc=0;
+  for (i = 1; i < argc; i++)
+    {
+      if (STREQ (argv[i], dumpscript_opt))
+	{
+EOF
+	    case $host in
+	      *mingw* | *cygwin* )
+		# make stdout use "unix" line endings
+		echo "          setmode(1,_O_BINARY);"
+		;;
+	      esac
+
+	    cat <<"EOF"
+	  lt_dump_script (stdout);
+	  return 0;
+	}
+      if (STREQ (argv[i], debug_opt))
+	{
+          lt_debug = 1;
+          continue;
+	}
+      if (STREQ (argv[i], ltwrapper_option_prefix))
+        {
+          /* however, if there is an option in the LTWRAPPER_OPTION_PREFIX
+             namespace, but it is not one of the ones we know about and
+             have already dealt with, above (inluding dump-script), then
+             report an error. Otherwise, targets might begin to believe
+             they are allowed to use options in the LTWRAPPER_OPTION_PREFIX
+             namespace. The first time any user complains about this, we'll
+             need to make LTWRAPPER_OPTION_PREFIX a configure-time option
+             or a configure.ac-settable value.
+           */
+          lt_fatal (__FILE__, __LINE__,
+		    "unrecognized %s option: '%s'",
+                    ltwrapper_option_prefix, argv[i]);
+        }
+      /* otherwise ... */
+      newargz[++newargc] = xstrdup (argv[i]);
+    }
+  newargz[++newargc] = NULL;
+
+EOF
+	    cat <<EOF
+  /* The GNU banner must be the first non-error debug message */
+  lt_debugprintf (__FILE__, __LINE__, "libtool wrapper (GNU $PACKAGE) $VERSION\n");
+EOF
+	    cat <<"EOF"
+  lt_debugprintf (__FILE__, __LINE__, "(main) argv[0]: %s\n", argv[0]);
+  lt_debugprintf (__FILE__, __LINE__, "(main) program_name: %s\n", program_name);
+
+  tmp_pathspec = find_executable (argv[0]);
+  if (tmp_pathspec == NULL)
+    lt_fatal (__FILE__, __LINE__, "couldn't find %s", argv[0]);
+  lt_debugprintf (__FILE__, __LINE__,
+                  "(main) found exe (before symlink chase) at: %s\n",
+		  tmp_pathspec);
+
+  actual_cwrapper_path = chase_symlinks (tmp_pathspec);
+  lt_debugprintf (__FILE__, __LINE__,
+                  "(main) found exe (after symlink chase) at: %s\n",
+		  actual_cwrapper_path);
+  XFREE (tmp_pathspec);
+
+  actual_cwrapper_name = xstrdup (base_name (actual_cwrapper_path));
+  strendzap (actual_cwrapper_path, actual_cwrapper_name);
+
+  /* wrapper name transforms */
+  strendzap (actual_cwrapper_name, ".exe");
+  tmp_pathspec = lt_extend_str (actual_cwrapper_name, ".exe", 1);
+  XFREE (actual_cwrapper_name);
+  actual_cwrapper_name = tmp_pathspec;
+  tmp_pathspec = 0;
+
+  /* target_name transforms -- use actual target program name; might have lt- prefix */
+  target_name = xstrdup (base_name (TARGET_PROGRAM_NAME));
+  strendzap (target_name, ".exe");
+  tmp_pathspec = lt_extend_str (target_name, ".exe", 1);
+  XFREE (target_name);
+  target_name = tmp_pathspec;
+  tmp_pathspec = 0;
+
+  lt_debugprintf (__FILE__, __LINE__,
+		  "(main) libtool target name: %s\n",
+		  target_name);
+EOF
+
+	    cat <<EOF
+  newargz[0] =
+    XMALLOC (char, (strlen (actual_cwrapper_path) +
+		    strlen ("$objdir") + 1 + strlen (actual_cwrapper_name) + 1));
+  strcpy (newargz[0], actual_cwrapper_path);
+  strcat (newargz[0], "$objdir");
+  strcat (newargz[0], "/");
+EOF
+
+	    cat <<"EOF"
+  /* stop here, and copy so we don't have to do this twice */
+  tmp_pathspec = xstrdup (newargz[0]);
+
+  /* do NOT want the lt- prefix here, so use actual_cwrapper_name */
+  strcat (newargz[0], actual_cwrapper_name);
+
+  /* DO want the lt- prefix here if it exists, so use target_name */
+  lt_argv_zero = lt_extend_str (tmp_pathspec, target_name, 1);
+  XFREE (tmp_pathspec);
+  tmp_pathspec = NULL;
+EOF
+
+	    case $host_os in
+	      mingw*)
+	    cat <<"EOF"
+  {
+    char* p;
+    while ((p = strchr (newargz[0], '\\')) != NULL)
+      {
+	*p = '/';
+      }
+    while ((p = strchr (lt_argv_zero, '\\')) != NULL)
+      {
+	*p = '/';
+      }
+  }
+EOF
+	    ;;
+	    esac
+
+	    cat <<"EOF"
+  XFREE (target_name);
+  XFREE (actual_cwrapper_path);
+  XFREE (actual_cwrapper_name);
+
+  lt_setenv ("BIN_SH", "xpg4"); /* for Tru64 */
+  lt_setenv ("DUALCASE", "1");  /* for MSK sh */
+  /* Update the DLL searchpath.  EXE_PATH_VALUE ($dllsearchpath) must
+     be prepended before (that is, appear after) LIB_PATH_VALUE ($temp_rpath)
+     because on Windows, both *_VARNAMEs are PATH but uninstalled
+     libraries must come first. */
+  lt_update_exe_path (EXE_PATH_VARNAME, EXE_PATH_VALUE);
+  lt_update_lib_path (LIB_PATH_VARNAME, LIB_PATH_VALUE);
+
+  lt_debugprintf (__FILE__, __LINE__, "(main) lt_argv_zero: %s\n",
+		  nonnull (lt_argv_zero));
+  for (i = 0; i < newargc; i++)
+    {
+      lt_debugprintf (__FILE__, __LINE__, "(main) newargz[%d]: %s\n",
+		      i, nonnull (newargz[i]));
+    }
+
+EOF
+
+	    case $host_os in
+	      mingw*)
+		cat <<"EOF"
+  /* execv doesn't actually work on mingw as expected on unix */
+  newargz = prepare_spawn (newargz);
+  rval = (int) _spawnv (_P_WAIT, lt_argv_zero, (const char * const *) newargz);
+  if (rval == -1)
+    {
+      /* failed to start process */
+      lt_debugprintf (__FILE__, __LINE__,
+		      "(main) failed to launch target \"%s\": %s\n",
+		      lt_argv_zero, nonnull (strerror (errno)));
+      return 127;
+    }
+  return rval;
+EOF
+		;;
+	      *)
+		cat <<"EOF"
+  execv (lt_argv_zero, newargz);
+  return rval; /* =127, but avoids unused variable warning */
+EOF
+		;;
+	    esac
+
+	    cat <<"EOF"
+}
+
+void *
+xmalloc (size_t num)
+{
+  void *p = (void *) malloc (num);
+  if (!p)
+    lt_fatal (__FILE__, __LINE__, "memory exhausted");
+
+  return p;
+}
+
+char *
+xstrdup (const char *string)
+{
+  return string ? strcpy ((char *) xmalloc (strlen (string) + 1),
+			  string) : NULL;
+}
+
+const char *
+base_name (const char *name)
+{
+  const char *base;
+
+#if defined HAVE_DOS_BASED_FILE_SYSTEM
+  /* Skip over the disk name in MSDOS pathnames. */
+  if (isalpha ((unsigned char) name[0]) && name[1] == ':')
+    name += 2;
+#endif
+
+  for (base = name; *name; name++)
+    if (IS_DIR_SEPARATOR (*name))
+      base = name + 1;
+  return base;
+}
+
+int
+check_executable (const char *path)
+{
+  struct stat st;
+
+  lt_debugprintf (__FILE__, __LINE__, "(check_executable): %s\n",
+                  nonempty (path));
+  if ((!path) || (!*path))
+    return 0;
+
+  if ((stat (path, &st) >= 0)
+      && (st.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)))
+    return 1;
+  else
+    return 0;
+}
+
+int
+make_executable (const char *path)
+{
+  int rval = 0;
+  struct stat st;
+
+  lt_debugprintf (__FILE__, __LINE__, "(make_executable): %s\n",
+                  nonempty (path));
+  if ((!path) || (!*path))
+    return 0;
+
+  if (stat (path, &st) >= 0)
+    {
+      rval = chmod (path, st.st_mode | S_IXOTH | S_IXGRP | S_IXUSR);
+    }
+  return rval;
+}
+
+/* Searches for the full path of the wrapper.  Returns
+   newly allocated full path name if found, NULL otherwise
+   Does not chase symlinks, even on platforms that support them.
+*/
+char *
+find_executable (const char *wrapper)
+{
+  int has_slash = 0;
+  const char *p;
+  const char *p_next;
+  /* static buffer for getcwd */
+  char tmp[LT_PATHMAX + 1];
+  size_t tmp_len;
+  char *concat_name;
+
+  lt_debugprintf (__FILE__, __LINE__, "(find_executable): %s\n",
+                  nonempty (wrapper));
+
+  if ((wrapper == NULL) || (*wrapper == '\0'))
+    return NULL;
+
+  /* Absolute path? */
+#if defined HAVE_DOS_BASED_FILE_SYSTEM
+  if (isalpha ((unsigned char) wrapper[0]) && wrapper[1] == ':')
+    {
+      concat_name = xstrdup (wrapper);
+      if (check_executable (concat_name))
+	return concat_name;
+      XFREE (concat_name);
+    }
+  else
+    {
+#endif
+      if (IS_DIR_SEPARATOR (wrapper[0]))
+	{
+	  concat_name = xstrdup (wrapper);
+	  if (check_executable (concat_name))
+	    return concat_name;
+	  XFREE (concat_name);
+	}
+#if defined HAVE_DOS_BASED_FILE_SYSTEM
+    }
+#endif
+
+  for (p = wrapper; *p; p++)
+    if (*p == '/')
+      {
+	has_slash = 1;
+	break;
+      }
+  if (!has_slash)
+    {
+      /* no slashes; search PATH */
+      const char *path = getenv ("PATH");
+      if (path != NULL)
+	{
+	  for (p = path; *p; p = p_next)
+	    {
+	      const char *q;
+	      size_t p_len;
+	      for (q = p; *q; q++)
+		if (IS_PATH_SEPARATOR (*q))
+		  break;
+	      p_len = (size_t) (q - p);
+	      p_next = (*q == '\0' ? q : q + 1);
+	      if (p_len == 0)
+		{
+		  /* empty path: current directory */
+		  if (getcwd (tmp, LT_PATHMAX) == NULL)
+		    lt_fatal (__FILE__, __LINE__, "getcwd failed: %s",
+                              nonnull (strerror (errno)));
+		  tmp_len = strlen (tmp);
+		  concat_name =
+		    XMALLOC (char, tmp_len + 1 + strlen (wrapper) + 1);
+		  memcpy (concat_name, tmp, tmp_len);
+		  concat_name[tmp_len] = '/';
+		  strcpy (concat_name + tmp_len + 1, wrapper);
+		}
+	      else
+		{
+		  concat_name =
+		    XMALLOC (char, p_len + 1 + strlen (wrapper) + 1);
+		  memcpy (concat_name, p, p_len);
+		  concat_name[p_len] = '/';
+		  strcpy (concat_name + p_len + 1, wrapper);
+		}
+	      if (check_executable (concat_name))
+		return concat_name;
+	      XFREE (concat_name);
+	    }
+	}
+      /* not found in PATH; assume curdir */
+    }
+  /* Relative path | not found in path: prepend cwd */
+  if (getcwd (tmp, LT_PATHMAX) == NULL)
+    lt_fatal (__FILE__, __LINE__, "getcwd failed: %s",
+              nonnull (strerror (errno)));
+  tmp_len = strlen (tmp);
+  concat_name = XMALLOC (char, tmp_len + 1 + strlen (wrapper) + 1);
+  memcpy (concat_name, tmp, tmp_len);
+  concat_name[tmp_len] = '/';
+  strcpy (concat_name + tmp_len + 1, wrapper);
+
+  if (check_executable (concat_name))
+    return concat_name;
+  XFREE (concat_name);
+  return NULL;
+}
+
+char *
+chase_symlinks (const char *pathspec)
+{
+#ifndef S_ISLNK
+  return xstrdup (pathspec);
+#else
+  char buf[LT_PATHMAX];
+  struct stat s;
+  char *tmp_pathspec = xstrdup (pathspec);
+  char *p;
+  int has_symlinks = 0;
+  while (strlen (tmp_pathspec) && !has_symlinks)
+    {
+      lt_debugprintf (__FILE__, __LINE__,
+		      "checking path component for symlinks: %s\n",
+		      tmp_pathspec);
+      if (lstat (tmp_pathspec, &s) == 0)
+	{
+	  if (S_ISLNK (s.st_mode) != 0)
+	    {
+	      has_symlinks = 1;
+	      break;
+	    }
+
+	  /* search backwards for last DIR_SEPARATOR */
+	  p = tmp_pathspec + strlen (tmp_pathspec) - 1;
+	  while ((p > tmp_pathspec) && (!IS_DIR_SEPARATOR (*p)))
+	    p--;
+	  if ((p == tmp_pathspec) && (!IS_DIR_SEPARATOR (*p)))
+	    {
+	      /* no more DIR_SEPARATORS left */
+	      break;
+	    }
+	  *p = '\0';
+	}
+      else
+	{
+	  lt_fatal (__FILE__, __LINE__,
+		    "error accessing file \"%s\": %s",
+		    tmp_pathspec, nonnull (strerror (errno)));
+	}
+    }
+  XFREE (tmp_pathspec);
+
+  if (!has_symlinks)
+    {
+      return xstrdup (pathspec);
+    }
+
+  tmp_pathspec = realpath (pathspec, buf);
+  if (tmp_pathspec == 0)
+    {
+      lt_fatal (__FILE__, __LINE__,
+		"could not follow symlinks for %s", pathspec);
+    }
+  return xstrdup (tmp_pathspec);
+#endif
+}
+
+char *
+strendzap (char *str, const char *pat)
+{
+  size_t len, patlen;
+
+  assert (str != NULL);
+  assert (pat != NULL);
+
+  len = strlen (str);
+  patlen = strlen (pat);
+
+  if (patlen <= len)
+    {
+      str += len - patlen;
+      if (STREQ (str, pat))
+	*str = '\0';
+    }
+  return str;
+}
+
+void
+lt_debugprintf (const char *file, int line, const char *fmt, ...)
+{
+  va_list args;
+  if (lt_debug)
+    {
+      (void) fprintf (stderr, "%s:%s:%d: ", program_name, file, line);
+      va_start (args, fmt);
+      (void) vfprintf (stderr, fmt, args);
+      va_end (args);
+    }
+}
+
+static void
+lt_error_core (int exit_status, const char *file,
+	       int line, const char *mode,
+	       const char *message, va_list ap)
+{
+  fprintf (stderr, "%s:%s:%d: %s: ", program_name, file, line, mode);
+  vfprintf (stderr, message, ap);
+  fprintf (stderr, ".\n");
+
+  if (exit_status >= 0)
+    exit (exit_status);
+}
+
+void
+lt_fatal (const char *file, int line, const char *message, ...)
+{
+  va_list ap;
+  va_start (ap, message);
+  lt_error_core (EXIT_FAILURE, file, line, "FATAL", message, ap);
+  va_end (ap);
+}
+
+static const char *
+nonnull (const char *s)
+{
+  return s ? s : "(null)";
+}
+
+static const char *
+nonempty (const char *s)
+{
+  return (s && !*s) ? "(empty)" : nonnull (s);
+}
+
+void
+lt_setenv (const char *name, const char *value)
+{
+  lt_debugprintf (__FILE__, __LINE__,
+		  "(lt_setenv) setting '%s' to '%s'\n",
+                  nonnull (name), nonnull (value));
+  {
+#ifdef HAVE_SETENV
+    /* always make a copy, for consistency with !HAVE_SETENV */
+    char *str = xstrdup (value);
+    setenv (name, str, 1);
+#else
+    size_t len = strlen (name) + 1 + strlen (value) + 1;
+    char *str = XMALLOC (char, len);
+    sprintf (str, "%s=%s", name, value);
+    if (putenv (str) != EXIT_SUCCESS)
+      {
+        XFREE (str);
+      }
+#endif
+  }
+}
+
+char *
+lt_extend_str (const char *orig_value, const char *add, int to_end)
+{
+  char *new_value;
+  if (orig_value && *orig_value)
+    {
+      size_t orig_value_len = strlen (orig_value);
+      size_t add_len = strlen (add);
+      new_value = XMALLOC (char, add_len + orig_value_len + 1);
+      if (to_end)
+        {
+          strcpy (new_value, orig_value);
+          strcpy (new_value + orig_value_len, add);
+        }
+      else
+        {
+          strcpy (new_value, add);
+          strcpy (new_value + add_len, orig_value);
+        }
+    }
+  else
+    {
+      new_value = xstrdup (add);
+    }
+  return new_value;
+}
+
+void
+lt_update_exe_path (const char *name, const char *value)
+{
+  lt_debugprintf (__FILE__, __LINE__,
+		  "(lt_update_exe_path) modifying '%s' by prepending '%s'\n",
+                  nonnull (name), nonnull (value));
+
+  if (name && *name && value && *value)
+    {
+      char *new_value = lt_extend_str (getenv (name), value, 0);
+      /* some systems can't cope with a ':'-terminated path #' */
+      size_t len = strlen (new_value);
+      while ((len > 0) && IS_PATH_SEPARATOR (new_value[len-1]))
+        {
+          new_value[--len] = '\0';
+        }
+      lt_setenv (name, new_value);
+      XFREE (new_value);
+    }
+}
+
+void
+lt_update_lib_path (const char *name, const char *value)
+{
+  lt_debugprintf (__FILE__, __LINE__,
+		  "(lt_update_lib_path) modifying '%s' by prepending '%s'\n",
+                  nonnull (name), nonnull (value));
+
+  if (name && *name && value && *value)
+    {
+      char *new_value = lt_extend_str (getenv (name), value, 0);
+      lt_setenv (name, new_value);
+      XFREE (new_value);
+    }
+}
+
+EOF
+	    case $host_os in
+	      mingw*)
+		cat <<"EOF"
+
+/* Prepares an argument vector before calling spawn().
+   Note that spawn() does not by itself call the command interpreter
+     (getenv ("COMSPEC") != NULL ? getenv ("COMSPEC") :
+      ({ OSVERSIONINFO v; v.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
+         GetVersionEx(&v);
+         v.dwPlatformId == VER_PLATFORM_WIN32_NT;
+      }) ? "cmd.exe" : "command.com").
+   Instead it simply concatenates the arguments, separated by ' ', and calls
+   CreateProcess().  We must quote the arguments since Win32 CreateProcess()
+   interprets characters like ' ', '\t', '\\', '"' (but not '<' and '>') in a
+   special way:
+   - Space and tab are interpreted as delimiters. They are not treated as
+     delimiters if they are surrounded by double quotes: "...".
+   - Unescaped double quotes are removed from the input. Their only effect is
+     that within double quotes, space and tab are treated like normal
+     characters.
+   - Backslashes not followed by double quotes are not special.
+   - But 2*n+1 backslashes followed by a double quote become
+     n backslashes followed by a double quote (n >= 0):
+       \" -> "
+       \\\" -> \"
+       \\\\\" -> \\"
+ */
+#define SHELL_SPECIAL_CHARS "\"\\ \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037"
+#define SHELL_SPACE_CHARS " \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037"
+char **
+prepare_spawn (char **argv)
+{
+  size_t argc;
+  char **new_argv;
+  size_t i;
+
+  /* Count number of arguments.  */
+  for (argc = 0; argv[argc] != NULL; argc++)
+    ;
+
+  /* Allocate new argument vector.  */
+  new_argv = XMALLOC (char *, argc + 1);
+
+  /* Put quoted arguments into the new argument vector.  */
+  for (i = 0; i < argc; i++)
+    {
+      const char *string = argv[i];
+
+      if (string[0] == '\0')
+	new_argv[i] = xstrdup ("\"\"");
+      else if (strpbrk (string, SHELL_SPECIAL_CHARS) != NULL)
+	{
+	  int quote_around = (strpbrk (string, SHELL_SPACE_CHARS) != NULL);
+	  size_t length;
+	  unsigned int backslashes;
+	  const char *s;
+	  char *quoted_string;
+	  char *p;
+
+	  length = 0;
+	  backslashes = 0;
+	  if (quote_around)
+	    length++;
+	  for (s = string; *s != '\0'; s++)
+	    {
+	      char c = *s;
+	      if (c == '"')
+		length += backslashes + 1;
+	      length++;
+	      if (c == '\\')
+		backslashes++;
+	      else
+		backslashes = 0;
+	    }
+	  if (quote_around)
+	    length += backslashes + 1;
+
+	  quoted_string = XMALLOC (char, length + 1);
+
+	  p = quoted_string;
+	  backslashes = 0;
+	  if (quote_around)
+	    *p++ = '"';
+	  for (s = string; *s != '\0'; s++)
+	    {
+	      char c = *s;
+	      if (c == '"')
+		{
+		  unsigned int j;
+		  for (j = backslashes + 1; j > 0; j--)
+		    *p++ = '\\';
+		}
+	      *p++ = c;
+	      if (c == '\\')
+		backslashes++;
+	      else
+		backslashes = 0;
+	    }
+	  if (quote_around)
+	    {
+	      unsigned int j;
+	      for (j = backslashes; j > 0; j--)
+		*p++ = '\\';
+	      *p++ = '"';
+	    }
+	  *p = '\0';
+
+	  new_argv[i] = quoted_string;
+	}
+      else
+	new_argv[i] = (char *) string;
+    }
+  new_argv[argc] = NULL;
+
+  return new_argv;
+}
+EOF
+		;;
+	    esac
+
+            cat <<"EOF"
+void lt_dump_script (FILE* f)
+{
+EOF
+	    func_emit_wrapper yes |
+	      $SED -n -e '
+s/^\(.\{79\}\)\(..*\)/\1\
+\2/
+h
+s/\([\\"]\)/\\\1/g
+s/$/\\n/
+s/\([^\n]*\).*/  fputs ("\1", f);/p
+g
+D'
+            cat <<"EOF"
+}
+EOF
+}
+# end: func_emit_cwrapperexe_src
+
+# func_win32_import_lib_p ARG
+# True if ARG is an import lib, as indicated by $file_magic_cmd
+func_win32_import_lib_p ()
+{
+    $debug_cmd
+
+    case `eval $file_magic_cmd \"\$1\" 2>/dev/null | $SED -e 10q` in
+    *import*) : ;;
+    *) false ;;
+    esac
+}
+
+# func_suncc_cstd_abi
+# !!ONLY CALL THIS FOR SUN CC AFTER $compile_command IS FULLY EXPANDED!!
+# Several compiler flags select an ABI that is incompatible with the
+# Cstd library. Avoid specifying it if any are in CXXFLAGS.
+func_suncc_cstd_abi ()
+{
+    $debug_cmd
+
+    case " $compile_command " in
+    *" -compat=g "*|*\ -std=c++[0-9][0-9]\ *|*" -library=stdcxx4 "*|*" -library=stlport4 "*)
+      suncc_use_cstd_abi=no
+      ;;
+    *)
+      suncc_use_cstd_abi=yes
+      ;;
+    esac
+}
+
+# func_mode_link arg...
+func_mode_link ()
+{
+    $debug_cmd
+
+    case $host in
+    *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
+      # It is impossible to link a dll without this setting, and
+      # we shouldn't force the makefile maintainer to figure out
+      # what system we are compiling for in order to pass an extra
+      # flag for every libtool invocation.
+      # allow_undefined=no
+
+      # FIXME: Unfortunately, there are problems with the above when trying
+      # to make a dll that has undefined symbols, in which case not
+      # even a static library is built.  For now, we need to specify
+      # -no-undefined on the libtool link line when we can be certain
+      # that all symbols are satisfied, otherwise we get a static library.
+      allow_undefined=yes
+      ;;
+    *)
+      allow_undefined=yes
+      ;;
+    esac
+    libtool_args=$nonopt
+    base_compile="$nonopt $@"
+    compile_command=$nonopt
+    finalize_command=$nonopt
+
+    compile_rpath=
+    finalize_rpath=
+    compile_shlibpath=
+    finalize_shlibpath=
+    convenience=
+    old_convenience=
+    deplibs=
+    old_deplibs=
+    compiler_flags=
+    linker_flags=
+    dllsearchpath=
+    lib_search_path=`pwd`
+    inst_prefix_dir=
+    new_inherited_linker_flags=
+
+    avoid_version=no
+    bindir=
+    dlfiles=
+    dlprefiles=
+    dlself=no
+    export_dynamic=no
+    export_symbols=
+    export_symbols_regex=
+    generated=
+    libobjs=
+    ltlibs=
+    module=no
+    no_install=no
+    objs=
+    os2dllname=
+    non_pic_objects=
+    precious_files_regex=
+    prefer_static_libs=no
+    preload=false
+    prev=
+    prevarg=
+    release=
+    rpath=
+    xrpath=
+    perm_rpath=
+    temp_rpath=
+    thread_safe=no
+    vinfo=
+    vinfo_number=no
+    weak_libs=
+    single_module=$wl-single_module
+    func_infer_tag $base_compile
+
+    # We need to know -static, to get the right output filenames.
+    for arg
+    do
+      case $arg in
+      -shared)
+	test yes != "$build_libtool_libs" \
+	  && func_fatal_configuration "cannot build a shared library"
+	build_old_libs=no
+	break
+	;;
+      -all-static | -static | -static-libtool-libs)
+	case $arg in
+	-all-static)
+	  if test yes = "$build_libtool_libs" && test -z "$link_static_flag"; then
+	    func_warning "complete static linking is impossible in this configuration"
+	  fi
+	  if test -n "$link_static_flag"; then
+	    dlopen_self=$dlopen_self_static
+	  fi
+	  prefer_static_libs=yes
+	  ;;
+	-static)
+	  if test -z "$pic_flag" && test -n "$link_static_flag"; then
+	    dlopen_self=$dlopen_self_static
+	  fi
+	  prefer_static_libs=built
+	  ;;
+	-static-libtool-libs)
+	  if test -z "$pic_flag" && test -n "$link_static_flag"; then
+	    dlopen_self=$dlopen_self_static
+	  fi
+	  prefer_static_libs=yes
+	  ;;
+	esac
+	build_libtool_libs=no
+	build_old_libs=yes
+	break
+	;;
+      esac
+    done
+
+    # See if our shared archives depend on static archives.
+    test -n "$old_archive_from_new_cmds" && build_old_libs=yes
+
+    # Go through the arguments, transforming them on the way.
+    while test "$#" -gt 0; do
+      arg=$1
+      shift
+      func_quote_for_eval "$arg"
+      qarg=$func_quote_for_eval_unquoted_result
+      func_append libtool_args " $func_quote_for_eval_result"
+
+      # If the previous option needs an argument, assign it.
+      if test -n "$prev"; then
+	case $prev in
+	output)
+	  func_append compile_command " @OUTPUT@"
+	  func_append finalize_command " @OUTPUT@"
+	  ;;
+	esac
+
+	case $prev in
+	bindir)
+	  bindir=$arg
+	  prev=
+	  continue
+	  ;;
+	dlfiles|dlprefiles)
+	  $preload || {
+	    # Add the symbol object into the linking commands.
+	    func_append compile_command " @SYMFILE@"
+	    func_append finalize_command " @SYMFILE@"
+	    preload=:
+	  }
+	  case $arg in
+	  *.la | *.lo) ;;  # We handle these cases below.
+	  force)
+	    if test no = "$dlself"; then
+	      dlself=needless
+	      export_dynamic=yes
+	    fi
+	    prev=
+	    continue
+	    ;;
+	  self)
+	    if test dlprefiles = "$prev"; then
+	      dlself=yes
+	    elif test dlfiles = "$prev" && test yes != "$dlopen_self"; then
+	      dlself=yes
+	    else
+	      dlself=needless
+	      export_dynamic=yes
+	    fi
+	    prev=
+	    continue
+	    ;;
+	  *)
+	    if test dlfiles = "$prev"; then
+	      func_append dlfiles " $arg"
+	    else
+	      func_append dlprefiles " $arg"
+	    fi
+	    prev=
+	    continue
+	    ;;
+	  esac
+	  ;;
+	expsyms)
+	  export_symbols=$arg
+	  test -f "$arg" \
+	    || func_fatal_error "symbol file '$arg' does not exist"
+	  prev=
+	  continue
+	  ;;
+	expsyms_regex)
+	  export_symbols_regex=$arg
+	  prev=
+	  continue
+	  ;;
+	framework)
+	  case $host in
+	    *-*-darwin*)
+	      case "$deplibs " in
+		*" $qarg.ltframework "*) ;;
+		*) func_append deplibs " $qarg.ltframework" # this is fixed later
+		   ;;
+	      esac
+	      ;;
+	  esac
+	  prev=
+	  continue
+	  ;;
+	inst_prefix)
+	  inst_prefix_dir=$arg
+	  prev=
+	  continue
+	  ;;
+	mllvm)
+	  # Clang does not use LLVM to link, so we can simply discard any
+	  # '-mllvm $arg' options when doing the link step.
+	  prev=
+	  continue
+	  ;;
+	objectlist)
+	  if test -f "$arg"; then
+	    save_arg=$arg
+	    moreargs=
+	    for fil in `cat "$save_arg"`
+	    do
+#	      func_append moreargs " $fil"
+	      arg=$fil
+	      # A libtool-controlled object.
+
+	      # Check to see that this really is a libtool object.
+	      if func_lalib_unsafe_p "$arg"; then
+		pic_object=
+		non_pic_object=
+
+		# Read the .lo file
+		func_source "$arg"
+
+		if test -z "$pic_object" ||
+		   test -z "$non_pic_object" ||
+		   test none = "$pic_object" &&
+		   test none = "$non_pic_object"; then
+		  func_fatal_error "cannot find name of object for '$arg'"
+		fi
+
+		# Extract subdirectory from the argument.
+		func_dirname "$arg" "/" ""
+		xdir=$func_dirname_result
+
+		if test none != "$pic_object"; then
+		  # Prepend the subdirectory the object is found in.
+		  pic_object=$xdir$pic_object
+
+		  if test dlfiles = "$prev"; then
+		    if test yes = "$build_libtool_libs" && test yes = "$dlopen_support"; then
+		      func_append dlfiles " $pic_object"
+		      prev=
+		      continue
+		    else
+		      # If libtool objects are unsupported, then we need to preload.
+		      prev=dlprefiles
+		    fi
+		  fi
+
+		  # CHECK ME:  I think I busted this.  -Ossama
+		  if test dlprefiles = "$prev"; then
+		    # Preload the old-style object.
+		    func_append dlprefiles " $pic_object"
+		    prev=
+		  fi
+
+		  # A PIC object.
+		  func_append libobjs " $pic_object"
+		  arg=$pic_object
+		fi
+
+		# Non-PIC object.
+		if test none != "$non_pic_object"; then
+		  # Prepend the subdirectory the object is found in.
+		  non_pic_object=$xdir$non_pic_object
+
+		  # A standard non-PIC object
+		  func_append non_pic_objects " $non_pic_object"
+		  if test -z "$pic_object" || test none = "$pic_object"; then
+		    arg=$non_pic_object
+		  fi
+		else
+		  # If the PIC object exists, use it instead.
+		  # $xdir was prepended to $pic_object above.
+		  non_pic_object=$pic_object
+		  func_append non_pic_objects " $non_pic_object"
+		fi
+	      else
+		# Only an error if not doing a dry-run.
+		if $opt_dry_run; then
+		  # Extract subdirectory from the argument.
+		  func_dirname "$arg" "/" ""
+		  xdir=$func_dirname_result
+
+		  func_lo2o "$arg"
+		  pic_object=$xdir$objdir/$func_lo2o_result
+		  non_pic_object=$xdir$func_lo2o_result
+		  func_append libobjs " $pic_object"
+		  func_append non_pic_objects " $non_pic_object"
+	        else
+		  func_fatal_error "'$arg' is not a valid libtool object"
+		fi
+	      fi
+	    done
+	  else
+	    func_fatal_error "link input file '$arg' does not exist"
+	  fi
+	  arg=$save_arg
+	  prev=
+	  continue
+	  ;;
+	os2dllname)
+	  os2dllname=$arg
+	  prev=
+	  continue
+	  ;;
+	precious_regex)
+	  precious_files_regex=$arg
+	  prev=
+	  continue
+	  ;;
+	release)
+	  release=-$arg
+	  prev=
+	  continue
+	  ;;
+	rpath | xrpath)
+	  # We need an absolute path.
+	  case $arg in
+	  [\\/]* | [A-Za-z]:[\\/]*) ;;
+	  *)
+	    func_fatal_error "only absolute run-paths are allowed"
+	    ;;
+	  esac
+	  if test rpath = "$prev"; then
+	    case "$rpath " in
+	    *" $arg "*) ;;
+	    *) func_append rpath " $arg" ;;
+	    esac
+	  else
+	    case "$xrpath " in
+	    *" $arg "*) ;;
+	    *) func_append xrpath " $arg" ;;
+	    esac
+	  fi
+	  prev=
+	  continue
+	  ;;
+	shrext)
+	  shrext_cmds=$arg
+	  prev=
+	  continue
+	  ;;
+	weak)
+	  func_append weak_libs " $arg"
+	  prev=
+	  continue
+	  ;;
+	xcclinker)
+	  func_append linker_flags " $qarg"
+	  func_append compiler_flags " $qarg"
+	  prev=
+	  func_append compile_command " $qarg"
+	  func_append finalize_command " $qarg"
+	  continue
+	  ;;
+	xcompiler)
+	  func_append compiler_flags " $qarg"
+	  prev=
+	  func_append compile_command " $qarg"
+	  func_append finalize_command " $qarg"
+	  continue
+	  ;;
+	xlinker)
+	  func_append linker_flags " $qarg"
+	  func_append compiler_flags " $wl$qarg"
+	  prev=
+	  func_append compile_command " $wl$qarg"
+	  func_append finalize_command " $wl$qarg"
+	  continue
+	  ;;
+	*)
+	  eval "$prev=\"\$arg\""
+	  prev=
+	  continue
+	  ;;
+	esac
+      fi # test -n "$prev"
+
+      prevarg=$arg
+
+      case $arg in
+      -all-static)
+	if test -n "$link_static_flag"; then
+	  # See comment for -static flag below, for more details.
+	  func_append compile_command " $link_static_flag"
+	  func_append finalize_command " $link_static_flag"
+	fi
+	continue
+	;;
+
+      -allow-undefined)
+	# FIXME: remove this flag sometime in the future.
+	func_fatal_error "'-allow-undefined' must not be used because it is the default"
+	;;
+
+      -avoid-version)
+	avoid_version=yes
+	continue
+	;;
+
+      -bindir)
+	prev=bindir
+	continue
+	;;
+
+      -dlopen)
+	prev=dlfiles
+	continue
+	;;
+
+      -dlpreopen)
+	prev=dlprefiles
+	continue
+	;;
+
+      -export-dynamic)
+	export_dynamic=yes
+	continue
+	;;
+
+      -export-symbols | -export-symbols-regex)
+	if test -n "$export_symbols" || test -n "$export_symbols_regex"; then
+	  func_fatal_error "more than one -exported-symbols argument is not allowed"
+	fi
+	if test X-export-symbols = "X$arg"; then
+	  prev=expsyms
+	else
+	  prev=expsyms_regex
+	fi
+	continue
+	;;
+
+      -framework)
+	prev=framework
+	continue
+	;;
+
+      -inst-prefix-dir)
+	prev=inst_prefix
+	continue
+	;;
+
+      # The native IRIX linker understands -LANG:*, -LIST:* and -LNO:*
+      # so, if we see these flags be careful not to treat them like -L
+      -L[A-Z][A-Z]*:*)
+	case $with_gcc/$host in
+	no/*-*-irix* | /*-*-irix*)
+	  func_append compile_command " $arg"
+	  func_append finalize_command " $arg"
+	  ;;
+	esac
+	continue
+	;;
+
+      -L*)
+	func_stripname "-L" '' "$arg"
+	if test -z "$func_stripname_result"; then
+	  if test "$#" -gt 0; then
+	    func_fatal_error "require no space between '-L' and '$1'"
+	  else
+	    func_fatal_error "need path for '-L' option"
+	  fi
+	fi
+	func_resolve_sysroot "$func_stripname_result"
+	dir=$func_resolve_sysroot_result
+	# We need an absolute path.
+	case $dir in
+	[\\/]* | [A-Za-z]:[\\/]*) ;;
+	*)
+	  absdir=`cd "$dir" && pwd`
+	  test -z "$absdir" && \
+	    func_fatal_error "cannot determine absolute directory name of '$dir'"
+	  dir=$absdir
+	  ;;
+	esac
+	case "$deplibs " in
+	*" -L$dir "* | *" $arg "*)
+	  # Will only happen for absolute or sysroot arguments
+	  ;;
+	*)
+	  # Preserve sysroot, but never include relative directories
+	  case $dir in
+	    [\\/]* | [A-Za-z]:[\\/]* | =*) func_append deplibs " $arg" ;;
+	    *) func_append deplibs " -L$dir" ;;
+	  esac
+	  func_append lib_search_path " $dir"
+	  ;;
+	esac
+	case $host in
+	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
+	  testbindir=`$ECHO "$dir" | $SED 's*/lib$*/bin*'`
+	  case :$dllsearchpath: in
+	  *":$dir:"*) ;;
+	  ::) dllsearchpath=$dir;;
+	  *) func_append dllsearchpath ":$dir";;
+	  esac
+	  case :$dllsearchpath: in
+	  *":$testbindir:"*) ;;
+	  ::) dllsearchpath=$testbindir;;
+	  *) func_append dllsearchpath ":$testbindir";;
+	  esac
+	  ;;
+	esac
+	continue
+	;;
+
+      -l*)
+	if test X-lc = "X$arg" || test X-lm = "X$arg"; then
+	  case $host in
+	  *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-beos* | *-cegcc* | *-*-haiku*)
+	    # These systems don't actually have a C or math library (as such)
+	    continue
+	    ;;
+	  *-*-os2*)
+	    # These systems don't actually have a C library (as such)
+	    test X-lc = "X$arg" && continue
+	    ;;
+	  *-*-openbsd* | *-*-freebsd* | *-*-dragonfly* | *-*-bitrig*)
+	    # Do not include libc due to us having libc/libc_r.
+	    test X-lc = "X$arg" && continue
+	    ;;
+	  *-*-rhapsody* | *-*-darwin1.[012])
+	    # Rhapsody C and math libraries are in the System framework
+	    func_append deplibs " System.ltframework"
+	    continue
+	    ;;
+	  *-*-sco3.2v5* | *-*-sco5v6*)
+	    # Causes problems with __ctype
+	    test X-lc = "X$arg" && continue
+	    ;;
+	  *-*-sysv4.2uw2* | *-*-sysv5* | *-*-unixware* | *-*-OpenUNIX*)
+	    # Compiler inserts libc in the correct place for threads to work
+	    test X-lc = "X$arg" && continue
+	    ;;
+	  esac
+	elif test X-lc_r = "X$arg"; then
+	 case $host in
+	 *-*-openbsd* | *-*-freebsd* | *-*-dragonfly* | *-*-bitrig*)
+	   # Do not include libc_r directly, use -pthread flag.
+	   continue
+	   ;;
+	 esac
+	fi
+	func_append deplibs " $arg"
+	continue
+	;;
+
+      -mllvm)
+	prev=mllvm
+	continue
+	;;
+
+      -module)
+	module=yes
+	continue
+	;;
+
+      # Tru64 UNIX uses -model [arg] to determine the layout of C++
+      # classes, name mangling, and exception handling.
+      # Darwin uses the -arch flag to determine output architecture.
+      -model|-arch|-isysroot|--sysroot)
+	func_append compiler_flags " $arg"
+	func_append compile_command " $arg"
+	func_append finalize_command " $arg"
+	prev=xcompiler
+	continue
+	;;
+
+      -mt|-mthreads|-kthread|-Kthread|-pthread|-pthreads|--thread-safe \
+      |-threads|-fopenmp|-openmp|-mp|-xopenmp|-omp|-qsmp=*)
+	func_append compiler_flags " $arg"
+	func_append compile_command " $arg"
+	func_append finalize_command " $arg"
+	case "$new_inherited_linker_flags " in
+	    *" $arg "*) ;;
+	    * ) func_append new_inherited_linker_flags " $arg" ;;
+	esac
+	continue
+	;;
+
+      -multi_module)
+	single_module=$wl-multi_module
+	continue
+	;;
+
+      -no-fast-install)
+	fast_install=no
+	continue
+	;;
+
+      -no-install)
+	case $host in
+	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-darwin* | *-cegcc*)
+	  # The PATH hackery in wrapper scripts is required on Windows
+	  # and Darwin in order for the loader to find any dlls it needs.
+	  func_warning "'-no-install' is ignored for $host"
+	  func_warning "assuming '-no-fast-install' instead"
+	  fast_install=no
+	  ;;
+	*) no_install=yes ;;
+	esac
+	continue
+	;;
+
+      -no-undefined)
+	allow_undefined=no
+	continue
+	;;
+
+      -objectlist)
+	prev=objectlist
+	continue
+	;;
+
+      -os2dllname)
+	prev=os2dllname
+	continue
+	;;
+
+      -o) prev=output ;;
+
+      -precious-files-regex)
+	prev=precious_regex
+	continue
+	;;
+
+      -release)
+	prev=release
+	continue
+	;;
+
+      -rpath)
+	prev=rpath
+	continue
+	;;
+
+      -R)
+	prev=xrpath
+	continue
+	;;
+
+      -R*)
+	func_stripname '-R' '' "$arg"
+	dir=$func_stripname_result
+	# We need an absolute path.
+	case $dir in
+	[\\/]* | [A-Za-z]:[\\/]*) ;;
+	=*)
+	  func_stripname '=' '' "$dir"
+	  dir=$lt_sysroot$func_stripname_result
+	  ;;
+	*)
+	  func_fatal_error "only absolute run-paths are allowed"
+	  ;;
+	esac
+	case "$xrpath " in
+	*" $dir "*) ;;
+	*) func_append xrpath " $dir" ;;
+	esac
+	continue
+	;;
+
+      -shared)
+	# The effects of -shared are defined in a previous loop.
+	continue
+	;;
+
+      -shrext)
+	prev=shrext
+	continue
+	;;
+
+      -static | -static-libtool-libs)
+	# The effects of -static are defined in a previous loop.
+	# We used to do the same as -all-static on platforms that
+	# didn't have a PIC flag, but the assumption that the effects
+	# would be equivalent was wrong.  It would break on at least
+	# Digital Unix and AIX.
+	continue
+	;;
+
+      -thread-safe)
+	thread_safe=yes
+	continue
+	;;
+
+      -version-info)
+	prev=vinfo
+	continue
+	;;
+
+      -version-number)
+	prev=vinfo
+	vinfo_number=yes
+	continue
+	;;
+
+      -weak)
+        prev=weak
+	continue
+	;;
+
+      -Wc,*)
+	func_stripname '-Wc,' '' "$arg"
+	args=$func_stripname_result
+	arg=
+	save_ifs=$IFS; IFS=,
+	for flag in $args; do
+	  IFS=$save_ifs
+          func_quote_for_eval "$flag"
+	  func_append arg " $func_quote_for_eval_result"
+	  func_append compiler_flags " $func_quote_for_eval_result"
+	done
+	IFS=$save_ifs
+	func_stripname ' ' '' "$arg"
+	arg=$func_stripname_result
+	;;
+
+      -Wl,*)
+	func_stripname '-Wl,' '' "$arg"
+	args=$func_stripname_result
+	arg=
+	save_ifs=$IFS; IFS=,
+	for flag in $args; do
+	  IFS=$save_ifs
+          func_quote_for_eval "$flag"
+	  func_append arg " $wl$func_quote_for_eval_result"
+	  func_append compiler_flags " $wl$func_quote_for_eval_result"
+	  func_append linker_flags " $func_quote_for_eval_result"
+	done
+	IFS=$save_ifs
+	func_stripname ' ' '' "$arg"
+	arg=$func_stripname_result
+	;;
+
+      -Xcompiler)
+	prev=xcompiler
+	continue
+	;;
+
+      -Xlinker)
+	prev=xlinker
+	continue
+	;;
+
+      -XCClinker)
+	prev=xcclinker
+	continue
+	;;
+
+      # -msg_* for osf cc
+      -msg_*)
+	func_quote_for_eval "$arg"
+	arg=$func_quote_for_eval_result
+	;;
+
+      # Flags to be passed through unchanged, with rationale:
+      # -64, -mips[0-9]      enable 64-bit mode for the SGI compiler
+      # -r[0-9][0-9]*        specify processor for the SGI compiler
+      # -xarch=*, -xtarget=* enable 64-bit mode for the Sun compiler
+      # +DA*, +DD*           enable 64-bit mode for the HP compiler
+      # -q*                  compiler args for the IBM compiler
+      # -m*, -t[45]*, -txscale* architecture-specific flags for GCC
+      # -F/path              path to uninstalled frameworks, gcc on darwin
+      # -p, -pg, --coverage, -fprofile-*  profiling flags for GCC
+      # -fstack-protector*   stack protector flags for GCC
+      # @file                GCC response files
+      # -tp=*                Portland pgcc target processor selection
+      # --sysroot=*          for sysroot support
+      # -O*, -g*, -flto*, -fwhopr*, -fuse-linker-plugin GCC link-time optimization
+      # -stdlib=*            select c++ std lib with clang
+      -64|-mips[0-9]|-r[0-9][0-9]*|-xarch=*|-xtarget=*|+DA*|+DD*|-q*|-m*| \
+      -t[45]*|-txscale*|-p|-pg|--coverage|-fprofile-*|-F*|@*|-tp=*|--sysroot=*| \
+      -O*|-g*|-flto*|-fwhopr*|-fuse-linker-plugin|-fstack-protector*|-stdlib=*)
+        func_quote_for_eval "$arg"
+	arg=$func_quote_for_eval_result
+        func_append compile_command " $arg"
+        func_append finalize_command " $arg"
+        func_append compiler_flags " $arg"
+        continue
+        ;;
+
+      -Z*)
+        if test os2 = "`expr $host : '.*\(os2\)'`"; then
+          # OS/2 uses -Zxxx to specify OS/2-specific options
+	  compiler_flags="$compiler_flags $arg"
+	  func_append compile_command " $arg"
+	  func_append finalize_command " $arg"
+	  case $arg in
+	  -Zlinker | -Zstack)
+	    prev=xcompiler
+	    ;;
+	  esac
+	  continue
+        else
+	  # Otherwise treat like 'Some other compiler flag' below
+	  func_quote_for_eval "$arg"
+	  arg=$func_quote_for_eval_result
+        fi
+	;;
+
+      # Some other compiler flag.
+      -* | +*)
+        func_quote_for_eval "$arg"
+	arg=$func_quote_for_eval_result
+	;;
+
+      *.$objext)
+	# A standard object.
+	func_append objs " $arg"
+	;;
+
+      *.lo)
+	# A libtool-controlled object.
+
+	# Check to see that this really is a libtool object.
+	if func_lalib_unsafe_p "$arg"; then
+	  pic_object=
+	  non_pic_object=
+
+	  # Read the .lo file
+	  func_source "$arg"
+
+	  if test -z "$pic_object" ||
+	     test -z "$non_pic_object" ||
+	     test none = "$pic_object" &&
+	     test none = "$non_pic_object"; then
+	    func_fatal_error "cannot find name of object for '$arg'"
+	  fi
+
+	  # Extract subdirectory from the argument.
+	  func_dirname "$arg" "/" ""
+	  xdir=$func_dirname_result
+
+	  test none = "$pic_object" || {
+	    # Prepend the subdirectory the object is found in.
+	    pic_object=$xdir$pic_object
+
+	    if test dlfiles = "$prev"; then
+	      if test yes = "$build_libtool_libs" && test yes = "$dlopen_support"; then
+		func_append dlfiles " $pic_object"
+		prev=
+		continue
+	      else
+		# If libtool objects are unsupported, then we need to preload.
+		prev=dlprefiles
+	      fi
+	    fi
+
+	    # CHECK ME:  I think I busted this.  -Ossama
+	    if test dlprefiles = "$prev"; then
+	      # Preload the old-style object.
+	      func_append dlprefiles " $pic_object"
+	      prev=
+	    fi
+
+	    # A PIC object.
+	    func_append libobjs " $pic_object"
+	    arg=$pic_object
+	  }
+
+	  # Non-PIC object.
+	  if test none != "$non_pic_object"; then
+	    # Prepend the subdirectory the object is found in.
+	    non_pic_object=$xdir$non_pic_object
+
+	    # A standard non-PIC object
+	    func_append non_pic_objects " $non_pic_object"
+	    if test -z "$pic_object" || test none = "$pic_object"; then
+	      arg=$non_pic_object
+	    fi
+	  else
+	    # If the PIC object exists, use it instead.
+	    # $xdir was prepended to $pic_object above.
+	    non_pic_object=$pic_object
+	    func_append non_pic_objects " $non_pic_object"
+	  fi
+	else
+	  # Only an error if not doing a dry-run.
+	  if $opt_dry_run; then
+	    # Extract subdirectory from the argument.
+	    func_dirname "$arg" "/" ""
+	    xdir=$func_dirname_result
+
+	    func_lo2o "$arg"
+	    pic_object=$xdir$objdir/$func_lo2o_result
+	    non_pic_object=$xdir$func_lo2o_result
+	    func_append libobjs " $pic_object"
+	    func_append non_pic_objects " $non_pic_object"
+	  else
+	    func_fatal_error "'$arg' is not a valid libtool object"
+	  fi
+	fi
+	;;
+
+      *.$libext)
+	# An archive.
+	func_append deplibs " $arg"
+	func_append old_deplibs " $arg"
+	continue
+	;;
+
+      *.la)
+	# A libtool-controlled library.
+
+	func_resolve_sysroot "$arg"
+	if test dlfiles = "$prev"; then
+	  # This library was specified with -dlopen.
+	  func_append dlfiles " $func_resolve_sysroot_result"
+	  prev=
+	elif test dlprefiles = "$prev"; then
+	  # The library was specified with -dlpreopen.
+	  func_append dlprefiles " $func_resolve_sysroot_result"
+	  prev=
+	else
+	  func_append deplibs " $func_resolve_sysroot_result"
+	fi
+	continue
+	;;
+
+      # Some other compiler argument.
+      *)
+	# Unknown arguments in both finalize_command and compile_command need
+	# to be aesthetically quoted because they are evaled later.
+	func_quote_for_eval "$arg"
+	arg=$func_quote_for_eval_result
+	;;
+      esac # arg
+
+      # Now actually substitute the argument into the commands.
+      if test -n "$arg"; then
+	func_append compile_command " $arg"
+	func_append finalize_command " $arg"
+      fi
+    done # argument parsing loop
+
+    test -n "$prev" && \
+      func_fatal_help "the '$prevarg' option requires an argument"
+
+    if test yes = "$export_dynamic" && test -n "$export_dynamic_flag_spec"; then
+      eval arg=\"$export_dynamic_flag_spec\"
+      func_append compile_command " $arg"
+      func_append finalize_command " $arg"
+    fi
+
+    oldlibs=
+    # calculate the name of the file, without its directory
+    func_basename "$output"
+    outputname=$func_basename_result
+    libobjs_save=$libobjs
+
+    if test -n "$shlibpath_var"; then
+      # get the directories listed in $shlibpath_var
+      eval shlib_search_path=\`\$ECHO \"\$$shlibpath_var\" \| \$SED \'s/:/ /g\'\`
+    else
+      shlib_search_path=
+    fi
+    eval sys_lib_search_path=\"$sys_lib_search_path_spec\"
+    eval sys_lib_dlsearch_path=\"$sys_lib_dlsearch_path_spec\"
+
+    # Definition is injected by LT_CONFIG during libtool generation.
+    func_munge_path_list sys_lib_dlsearch_path "$LT_SYS_LIBRARY_PATH"
+
+    func_dirname "$output" "/" ""
+    output_objdir=$func_dirname_result$objdir
+    func_to_tool_file "$output_objdir/"
+    tool_output_objdir=$func_to_tool_file_result
+    # Create the object directory.
+    func_mkdir_p "$output_objdir"
+
+    # Determine the type of output
+    case $output in
+    "")
+      func_fatal_help "you must specify an output file"
+      ;;
+    *.$libext) linkmode=oldlib ;;
+    *.lo | *.$objext) linkmode=obj ;;
+    *.la) linkmode=lib ;;
+    *) linkmode=prog ;; # Anything else should be a program.
+    esac
+
+    specialdeplibs=
+
+    libs=
+    # Find all interdependent deplibs by searching for libraries
+    # that are linked more than once (e.g. -la -lb -la)
+    for deplib in $deplibs; do
+      if $opt_preserve_dup_deps; then
+	case "$libs " in
+	*" $deplib "*) func_append specialdeplibs " $deplib" ;;
+	esac
+      fi
+      func_append libs " $deplib"
+    done
+
+    if test lib = "$linkmode"; then
+      libs="$predeps $libs $compiler_lib_search_path $postdeps"
+
+      # Compute libraries that are listed more than once in $predeps
+      # $postdeps and mark them as special (i.e., whose duplicates are
+      # not to be eliminated).
+      pre_post_deps=
+      if $opt_duplicate_compiler_generated_deps; then
+	for pre_post_dep in $predeps $postdeps; do
+	  case "$pre_post_deps " in
+	  *" $pre_post_dep "*) func_append specialdeplibs " $pre_post_deps" ;;
+	  esac
+	  func_append pre_post_deps " $pre_post_dep"
+	done
+      fi
+      pre_post_deps=
+    fi
+
+    deplibs=
+    newdependency_libs=
+    newlib_search_path=
+    need_relink=no # whether we're linking any uninstalled libtool libraries
+    notinst_deplibs= # not-installed libtool libraries
+    notinst_path= # paths that contain not-installed libtool libraries
+
+    case $linkmode in
+    lib)
+	passes="conv dlpreopen link"
+	for file in $dlfiles $dlprefiles; do
+	  case $file in
+	  *.la) ;;
+	  *)
+	    func_fatal_help "libraries can '-dlopen' only libtool libraries: $file"
+	    ;;
+	  esac
+	done
+	;;
+    prog)
+	compile_deplibs=
+	finalize_deplibs=
+	alldeplibs=false
+	newdlfiles=
+	newdlprefiles=
+	passes="conv scan dlopen dlpreopen link"
+	;;
+    *)  passes="conv"
+	;;
+    esac
+
+    for pass in $passes; do
+      # The preopen pass in lib mode reverses $deplibs; put it back here
+      # so that -L comes before libs that need it for instance...
+      if test lib,link = "$linkmode,$pass"; then
+	## FIXME: Find the place where the list is rebuilt in the wrong
+	##        order, and fix it there properly
+        tmp_deplibs=
+	for deplib in $deplibs; do
+	  tmp_deplibs="$deplib $tmp_deplibs"
+	done
+	deplibs=$tmp_deplibs
+      fi
+
+      if test lib,link = "$linkmode,$pass" ||
+	 test prog,scan = "$linkmode,$pass"; then
+	libs=$deplibs
+	deplibs=
+      fi
+      if test prog = "$linkmode"; then
+	case $pass in
+	dlopen) libs=$dlfiles ;;
+	dlpreopen) libs=$dlprefiles ;;
+	link) libs="$deplibs %DEPLIBS% $dependency_libs" ;;
+	esac
+      fi
+      if test lib,dlpreopen = "$linkmode,$pass"; then
+	# Collect and forward deplibs of preopened libtool libs
+	for lib in $dlprefiles; do
+	  # Ignore non-libtool-libs
+	  dependency_libs=
+	  func_resolve_sysroot "$lib"
+	  case $lib in
+	  *.la)	func_source "$func_resolve_sysroot_result" ;;
+	  esac
+
+	  # Collect preopened libtool deplibs, except any this library
+	  # has declared as weak libs
+	  for deplib in $dependency_libs; do
+	    func_basename "$deplib"
+            deplib_base=$func_basename_result
+	    case " $weak_libs " in
+	    *" $deplib_base "*) ;;
+	    *) func_append deplibs " $deplib" ;;
+	    esac
+	  done
+	done
+	libs=$dlprefiles
+      fi
+      if test dlopen = "$pass"; then
+	# Collect dlpreopened libraries
+	save_deplibs=$deplibs
+	deplibs=
+      fi
+
+      for deplib in $libs; do
+	lib=
+	found=false
+	case $deplib in
+	-mt|-mthreads|-kthread|-Kthread|-pthread|-pthreads|--thread-safe \
+        |-threads|-fopenmp|-openmp|-mp|-xopenmp|-omp|-qsmp=*)
+	  if test prog,link = "$linkmode,$pass"; then
+	    compile_deplibs="$deplib $compile_deplibs"
+	    finalize_deplibs="$deplib $finalize_deplibs"
+	  else
+	    func_append compiler_flags " $deplib"
+	    if test lib = "$linkmode"; then
+		case "$new_inherited_linker_flags " in
+		    *" $deplib "*) ;;
+		    * ) func_append new_inherited_linker_flags " $deplib" ;;
+		esac
+	    fi
+	  fi
+	  continue
+	  ;;
+	-l*)
+	  if test lib != "$linkmode" && test prog != "$linkmode"; then
+	    func_warning "'-l' is ignored for archives/objects"
+	    continue
+	  fi
+	  func_stripname '-l' '' "$deplib"
+	  name=$func_stripname_result
+	  if test lib = "$linkmode"; then
+	    searchdirs="$newlib_search_path $lib_search_path $compiler_lib_search_dirs $sys_lib_search_path $shlib_search_path"
+	  else
+	    searchdirs="$newlib_search_path $lib_search_path $sys_lib_search_path $shlib_search_path"
+	  fi
+	  for searchdir in $searchdirs; do
+	    for search_ext in .la $std_shrext .so .a; do
+	      # Search the libtool library
+	      lib=$searchdir/lib$name$search_ext
+	      if test -f "$lib"; then
+		if test .la = "$search_ext"; then
+		  found=:
+		else
+		  found=false
+		fi
+		break 2
+	      fi
+	    done
+	  done
+	  if $found; then
+	    # deplib is a libtool library
+	    # If $allow_libtool_libs_with_static_runtimes && $deplib is a stdlib,
+	    # We need to do some special things here, and not later.
+	    if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+	      case " $predeps $postdeps " in
+	      *" $deplib "*)
+		if func_lalib_p "$lib"; then
+		  library_names=
+		  old_library=
+		  func_source "$lib"
+		  for l in $old_library $library_names; do
+		    ll=$l
+		  done
+		  if test "X$ll" = "X$old_library"; then # only static version available
+		    found=false
+		    func_dirname "$lib" "" "."
+		    ladir=$func_dirname_result
+		    lib=$ladir/$old_library
+		    if test prog,link = "$linkmode,$pass"; then
+		      compile_deplibs="$deplib $compile_deplibs"
+		      finalize_deplibs="$deplib $finalize_deplibs"
+		    else
+		      deplibs="$deplib $deplibs"
+		      test lib = "$linkmode" && newdependency_libs="$deplib $newdependency_libs"
+		    fi
+		    continue
+		  fi
+		fi
+		;;
+	      *) ;;
+	      esac
+	    fi
+	  else
+	    # deplib doesn't seem to be a libtool library
+	    if test prog,link = "$linkmode,$pass"; then
+	      compile_deplibs="$deplib $compile_deplibs"
+	      finalize_deplibs="$deplib $finalize_deplibs"
+	    else
+	      deplibs="$deplib $deplibs"
+	      test lib = "$linkmode" && newdependency_libs="$deplib $newdependency_libs"
+	    fi
+	    continue
+	  fi
+	  ;; # -l
+	*.ltframework)
+	  if test prog,link = "$linkmode,$pass"; then
+	    compile_deplibs="$deplib $compile_deplibs"
+	    finalize_deplibs="$deplib $finalize_deplibs"
+	  else
+	    deplibs="$deplib $deplibs"
+	    if test lib = "$linkmode"; then
+		case "$new_inherited_linker_flags " in
+		    *" $deplib "*) ;;
+		    * ) func_append new_inherited_linker_flags " $deplib" ;;
+		esac
+	    fi
+	  fi
+	  continue
+	  ;;
+	-L*)
+	  case $linkmode in
+	  lib)
+	    deplibs="$deplib $deplibs"
+	    test conv = "$pass" && continue
+	    newdependency_libs="$deplib $newdependency_libs"
+	    func_stripname '-L' '' "$deplib"
+	    func_resolve_sysroot "$func_stripname_result"
+	    func_append newlib_search_path " $func_resolve_sysroot_result"
+	    ;;
+	  prog)
+	    if test conv = "$pass"; then
+	      deplibs="$deplib $deplibs"
+	      continue
+	    fi
+	    if test scan = "$pass"; then
+	      deplibs="$deplib $deplibs"
+	    else
+	      compile_deplibs="$deplib $compile_deplibs"
+	      finalize_deplibs="$deplib $finalize_deplibs"
+	    fi
+	    func_stripname '-L' '' "$deplib"
+	    func_resolve_sysroot "$func_stripname_result"
+	    func_append newlib_search_path " $func_resolve_sysroot_result"
+	    ;;
+	  *)
+	    func_warning "'-L' is ignored for archives/objects"
+	    ;;
+	  esac # linkmode
+	  continue
+	  ;; # -L
+	-R*)
+	  if test link = "$pass"; then
+	    func_stripname '-R' '' "$deplib"
+	    func_resolve_sysroot "$func_stripname_result"
+	    dir=$func_resolve_sysroot_result
+	    # Make sure the xrpath contains only unique directories.
+	    case "$xrpath " in
+	    *" $dir "*) ;;
+	    *) func_append xrpath " $dir" ;;
+	    esac
+	  fi
+	  deplibs="$deplib $deplibs"
+	  continue
+	  ;;
+	*.la)
+	  func_resolve_sysroot "$deplib"
+	  lib=$func_resolve_sysroot_result
+	  ;;
+	*.$libext)
+	  if test conv = "$pass"; then
+	    deplibs="$deplib $deplibs"
+	    continue
+	  fi
+	  case $linkmode in
+	  lib)
+	    # Linking convenience modules into shared libraries is allowed,
+	    # but linking other static libraries is non-portable.
+	    case " $dlpreconveniencelibs " in
+	    *" $deplib "*) ;;
+	    *)
+	      valid_a_lib=false
+	      case $deplibs_check_method in
+		match_pattern*)
+		  set dummy $deplibs_check_method; shift
+		  match_pattern_regex=`expr "$deplibs_check_method" : "$1 \(.*\)"`
+		  if eval "\$ECHO \"$deplib\"" 2>/dev/null | $SED 10q \
+		    | $EGREP "$match_pattern_regex" > /dev/null; then
+		    valid_a_lib=:
+		  fi
+		;;
+		pass_all)
+		  valid_a_lib=:
+		;;
+	      esac
+	      if $valid_a_lib; then
+		echo
+		$ECHO "*** Warning: Linking the shared library $output against the"
+		$ECHO "*** static library $deplib is not portable!"
+		deplibs="$deplib $deplibs"
+	      else
+		echo
+		$ECHO "*** Warning: Trying to link with static lib archive $deplib."
+		echo "*** I have the capability to make that library automatically link in when"
+		echo "*** you link to this library.  But I can only do this if you have a"
+		echo "*** shared version of the library, which you do not appear to have"
+		echo "*** because the file extensions .$libext of this argument makes me believe"
+		echo "*** that it is just a static archive that I should not use here."
+	      fi
+	      ;;
+	    esac
+	    continue
+	    ;;
+	  prog)
+	    if test link != "$pass"; then
+	      deplibs="$deplib $deplibs"
+	    else
+	      compile_deplibs="$deplib $compile_deplibs"
+	      finalize_deplibs="$deplib $finalize_deplibs"
+	    fi
+	    continue
+	    ;;
+	  esac # linkmode
+	  ;; # *.$libext
+	*.lo | *.$objext)
+	  if test conv = "$pass"; then
+	    deplibs="$deplib $deplibs"
+	  elif test prog = "$linkmode"; then
+	    if test dlpreopen = "$pass" || test yes != "$dlopen_support" || test no = "$build_libtool_libs"; then
+	      # If there is no dlopen support or we're linking statically,
+	      # we need to preload.
+	      func_append newdlprefiles " $deplib"
+	      compile_deplibs="$deplib $compile_deplibs"
+	      finalize_deplibs="$deplib $finalize_deplibs"
+	    else
+	      func_append newdlfiles " $deplib"
+	    fi
+	  fi
+	  continue
+	  ;;
+	%DEPLIBS%)
+	  alldeplibs=:
+	  continue
+	  ;;
+	esac # case $deplib
+
+	$found || test -f "$lib" \
+	  || func_fatal_error "cannot find the library '$lib' or unhandled argument '$deplib'"
+
+	# Check to see that this really is a libtool archive.
+	func_lalib_unsafe_p "$lib" \
+	  || func_fatal_error "'$lib' is not a valid libtool archive"
+
+	func_dirname "$lib" "" "."
+	ladir=$func_dirname_result
+
+	dlname=
+	dlopen=
+	dlpreopen=
+	libdir=
+	library_names=
+	old_library=
+	inherited_linker_flags=
+	# If the library was installed with an old release of libtool,
+	# it will not redefine variables installed, or shouldnotlink
+	installed=yes
+	shouldnotlink=no
+	avoidtemprpath=
+
+
+	# Read the .la file
+	func_source "$lib"
+
+	# Convert "-framework foo" to "foo.ltframework"
+	if test -n "$inherited_linker_flags"; then
+	  tmp_inherited_linker_flags=`$ECHO "$inherited_linker_flags" | $SED 's/-framework \([^ $]*\)/\1.ltframework/g'`
+	  for tmp_inherited_linker_flag in $tmp_inherited_linker_flags; do
+	    case " $new_inherited_linker_flags " in
+	      *" $tmp_inherited_linker_flag "*) ;;
+	      *) func_append new_inherited_linker_flags " $tmp_inherited_linker_flag";;
+	    esac
+	  done
+	fi
+	dependency_libs=`$ECHO " $dependency_libs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	if test lib,link = "$linkmode,$pass" ||
+	   test prog,scan = "$linkmode,$pass" ||
+	   { test prog != "$linkmode" && test lib != "$linkmode"; }; then
+	  test -n "$dlopen" && func_append dlfiles " $dlopen"
+	  test -n "$dlpreopen" && func_append dlprefiles " $dlpreopen"
+	fi
+
+	if test conv = "$pass"; then
+	  # Only check for convenience libraries
+	  deplibs="$lib $deplibs"
+	  if test -z "$libdir"; then
+	    if test -z "$old_library"; then
+	      func_fatal_error "cannot find name of link library for '$lib'"
+	    fi
+	    # It is a libtool convenience library, so add in its objects.
+	    func_append convenience " $ladir/$objdir/$old_library"
+	    func_append old_convenience " $ladir/$objdir/$old_library"
+	  elif test prog != "$linkmode" && test lib != "$linkmode"; then
+	    func_fatal_error "'$lib' is not a convenience library"
+	  fi
+	  tmp_libs=
+	  for deplib in $dependency_libs; do
+	    deplibs="$deplib $deplibs"
+	    if $opt_preserve_dup_deps; then
+	      case "$tmp_libs " in
+	      *" $deplib "*) func_append specialdeplibs " $deplib" ;;
+	      esac
+	    fi
+	    func_append tmp_libs " $deplib"
+	  done
+	  continue
+	fi # $pass = conv
+
+
+	# Get the name of the library we link against.
+	linklib=
+	if test -n "$old_library" &&
+	   { test yes = "$prefer_static_libs" ||
+	     test built,no = "$prefer_static_libs,$installed"; }; then
+	  linklib=$old_library
+	else
+	  for l in $old_library $library_names; do
+	    linklib=$l
+	  done
+	fi
+	if test -z "$linklib"; then
+	  func_fatal_error "cannot find name of link library for '$lib'"
+	fi
+
+	# This library was specified with -dlopen.
+	if test dlopen = "$pass"; then
+	  test -z "$libdir" \
+	    && func_fatal_error "cannot -dlopen a convenience library: '$lib'"
+	  if test -z "$dlname" ||
+	     test yes != "$dlopen_support" ||
+	     test no = "$build_libtool_libs"
+	  then
+	    # If there is no dlname, no dlopen support or we're linking
+	    # statically, we need to preload.  We also need to preload any
+	    # dependent libraries so libltdl's deplib preloader doesn't
+	    # bomb out in the load deplibs phase.
+	    func_append dlprefiles " $lib $dependency_libs"
+	  else
+	    func_append newdlfiles " $lib"
+	  fi
+	  continue
+	fi # $pass = dlopen
+
+	# We need an absolute path.
+	case $ladir in
+	[\\/]* | [A-Za-z]:[\\/]*) abs_ladir=$ladir ;;
+	*)
+	  abs_ladir=`cd "$ladir" && pwd`
+	  if test -z "$abs_ladir"; then
+	    func_warning "cannot determine absolute directory name of '$ladir'"
+	    func_warning "passing it literally to the linker, although it might fail"
+	    abs_ladir=$ladir
+	  fi
+	  ;;
+	esac
+	func_basename "$lib"
+	laname=$func_basename_result
+
+	# Find the relevant object directory and library name.
+	if test yes = "$installed"; then
+	  if test ! -f "$lt_sysroot$libdir/$linklib" && test -f "$abs_ladir/$linklib"; then
+	    func_warning "library '$lib' was moved."
+	    dir=$ladir
+	    absdir=$abs_ladir
+	    libdir=$abs_ladir
+	  else
+	    dir=$lt_sysroot$libdir
+	    absdir=$lt_sysroot$libdir
+	  fi
+	  test yes = "$hardcode_automatic" && avoidtemprpath=yes
+	else
+	  if test ! -f "$ladir/$objdir/$linklib" && test -f "$abs_ladir/$linklib"; then
+	    dir=$ladir
+	    absdir=$abs_ladir
+	    # Remove this search path later
+	    func_append notinst_path " $abs_ladir"
+	  else
+	    dir=$ladir/$objdir
+	    absdir=$abs_ladir/$objdir
+	    # Remove this search path later
+	    func_append notinst_path " $abs_ladir"
+	  fi
+	fi # $installed = yes
+	func_stripname 'lib' '.la' "$laname"
+	name=$func_stripname_result
+
+	# This library was specified with -dlpreopen.
+	if test dlpreopen = "$pass"; then
+	  if test -z "$libdir" && test prog = "$linkmode"; then
+	    func_fatal_error "only libraries may -dlpreopen a convenience library: '$lib'"
+	  fi
+	  case $host in
+	    # special handling for platforms with PE-DLLs.
+	    *cygwin* | *mingw* | *cegcc* )
+	      # Linker will automatically link against shared library if both
+	      # static and shared are present.  Therefore, ensure we extract
+	      # symbols from the import library if a shared library is present
+	      # (otherwise, the dlopen module name will be incorrect).  We do
+	      # this by putting the import library name into $newdlprefiles.
+	      # We recover the dlopen module name by 'saving' the la file
+	      # name in a special purpose variable, and (later) extracting the
+	      # dlname from the la file.
+	      if test -n "$dlname"; then
+	        func_tr_sh "$dir/$linklib"
+	        eval "libfile_$func_tr_sh_result=\$abs_ladir/\$laname"
+	        func_append newdlprefiles " $dir/$linklib"
+	      else
+	        func_append newdlprefiles " $dir/$old_library"
+	        # Keep a list of preopened convenience libraries to check
+	        # that they are being used correctly in the link pass.
+	        test -z "$libdir" && \
+	          func_append dlpreconveniencelibs " $dir/$old_library"
+	      fi
+	    ;;
+	    * )
+	      # Prefer using a static library (so that no silly _DYNAMIC symbols
+	      # are required to link).
+	      if test -n "$old_library"; then
+	        func_append newdlprefiles " $dir/$old_library"
+	        # Keep a list of preopened convenience libraries to check
+	        # that they are being used correctly in the link pass.
+	        test -z "$libdir" && \
+	          func_append dlpreconveniencelibs " $dir/$old_library"
+	      # Otherwise, use the dlname, so that lt_dlopen finds it.
+	      elif test -n "$dlname"; then
+	        func_append newdlprefiles " $dir/$dlname"
+	      else
+	        func_append newdlprefiles " $dir/$linklib"
+	      fi
+	    ;;
+	  esac
+	fi # $pass = dlpreopen
+
+	if test -z "$libdir"; then
+	  # Link the convenience library
+	  if test lib = "$linkmode"; then
+	    deplibs="$dir/$old_library $deplibs"
+	  elif test prog,link = "$linkmode,$pass"; then
+	    compile_deplibs="$dir/$old_library $compile_deplibs"
+	    finalize_deplibs="$dir/$old_library $finalize_deplibs"
+	  else
+	    deplibs="$lib $deplibs" # used for prog,scan pass
+	  fi
+	  continue
+	fi
+
+
+	if test prog = "$linkmode" && test link != "$pass"; then
+	  func_append newlib_search_path " $ladir"
+	  deplibs="$lib $deplibs"
+
+	  linkalldeplibs=false
+	  if test no != "$link_all_deplibs" || test -z "$library_names" ||
+	     test no = "$build_libtool_libs"; then
+	    linkalldeplibs=:
+	  fi
+
+	  tmp_libs=
+	  for deplib in $dependency_libs; do
+	    case $deplib in
+	    -L*) func_stripname '-L' '' "$deplib"
+	         func_resolve_sysroot "$func_stripname_result"
+	         func_append newlib_search_path " $func_resolve_sysroot_result"
+		 ;;
+	    esac
+	    # Need to link against all dependency_libs?
+	    if $linkalldeplibs; then
+	      deplibs="$deplib $deplibs"
+	    else
+	      # Need to hardcode shared library paths
+	      # or/and link against static libraries
+	      newdependency_libs="$deplib $newdependency_libs"
+	    fi
+	    if $opt_preserve_dup_deps; then
+	      case "$tmp_libs " in
+	      *" $deplib "*) func_append specialdeplibs " $deplib" ;;
+	      esac
+	    fi
+	    func_append tmp_libs " $deplib"
+	  done # for deplib
+	  continue
+	fi # $linkmode = prog...
+
+	if test prog,link = "$linkmode,$pass"; then
+	  if test -n "$library_names" &&
+	     { { test no = "$prefer_static_libs" ||
+	         test built,yes = "$prefer_static_libs,$installed"; } ||
+	       test -z "$old_library"; }; then
+	    # We need to hardcode the library path
+	    if test -n "$shlibpath_var" && test -z "$avoidtemprpath"; then
+	      # Make sure the rpath contains only unique directories.
+	      case $temp_rpath: in
+	      *"$absdir:"*) ;;
+	      *) func_append temp_rpath "$absdir:" ;;
+	      esac
+	    fi
+
+	    # Hardcode the library path.
+	    # Skip directories that are in the system default run-time
+	    # search path.
+	    case " $sys_lib_dlsearch_path " in
+	    *" $absdir "*) ;;
+	    *)
+	      case "$compile_rpath " in
+	      *" $absdir "*) ;;
+	      *) func_append compile_rpath " $absdir" ;;
+	      esac
+	      ;;
+	    esac
+	    case " $sys_lib_dlsearch_path " in
+	    *" $libdir "*) ;;
+	    *)
+	      case "$finalize_rpath " in
+	      *" $libdir "*) ;;
+	      *) func_append finalize_rpath " $libdir" ;;
+	      esac
+	      ;;
+	    esac
+	  fi # $linkmode,$pass = prog,link...
+
+	  if $alldeplibs &&
+	     { test pass_all = "$deplibs_check_method" ||
+	       { test yes = "$build_libtool_libs" &&
+		 test -n "$library_names"; }; }; then
+	    # We only need to search for static libraries
+	    continue
+	  fi
+	fi
+
+	link_static=no # Whether the deplib will be linked statically
+	use_static_libs=$prefer_static_libs
+	if test built = "$use_static_libs" && test yes = "$installed"; then
+	  use_static_libs=no
+	fi
+	if test -n "$library_names" &&
+	   { test no = "$use_static_libs" || test -z "$old_library"; }; then
+	  case $host in
+	  *cygwin* | *mingw* | *cegcc* | *os2*)
+	      # No point in relinking DLLs because paths are not encoded
+	      func_append notinst_deplibs " $lib"
+	      need_relink=no
+	    ;;
+	  *)
+	    if test no = "$installed"; then
+	      func_append notinst_deplibs " $lib"
+	      need_relink=yes
+	    fi
+	    ;;
+	  esac
+	  # This is a shared library
+
+	  # Warn about portability, can't link against -module's on some
+	  # systems (darwin).  Don't bleat about dlopened modules though!
+	  dlopenmodule=
+	  for dlpremoduletest in $dlprefiles; do
+	    if test "X$dlpremoduletest" = "X$lib"; then
+	      dlopenmodule=$dlpremoduletest
+	      break
+	    fi
+	  done
+	  if test -z "$dlopenmodule" && test yes = "$shouldnotlink" && test link = "$pass"; then
+	    echo
+	    if test prog = "$linkmode"; then
+	      $ECHO "*** Warning: Linking the executable $output against the loadable module"
+	    else
+	      $ECHO "*** Warning: Linking the shared library $output against the loadable module"
+	    fi
+	    $ECHO "*** $linklib is not portable!"
+	  fi
+	  if test lib = "$linkmode" &&
+	     test yes = "$hardcode_into_libs"; then
+	    # Hardcode the library path.
+	    # Skip directories that are in the system default run-time
+	    # search path.
+	    case " $sys_lib_dlsearch_path " in
+	    *" $absdir "*) ;;
+	    *)
+	      case "$compile_rpath " in
+	      *" $absdir "*) ;;
+	      *) func_append compile_rpath " $absdir" ;;
+	      esac
+	      ;;
+	    esac
+	    case " $sys_lib_dlsearch_path " in
+	    *" $libdir "*) ;;
+	    *)
+	      case "$finalize_rpath " in
+	      *" $libdir "*) ;;
+	      *) func_append finalize_rpath " $libdir" ;;
+	      esac
+	      ;;
+	    esac
+	  fi
+
+	  if test -n "$old_archive_from_expsyms_cmds"; then
+	    # figure out the soname
+	    set dummy $library_names
+	    shift
+	    realname=$1
+	    shift
+	    libname=`eval "\\$ECHO \"$libname_spec\""`
+	    # use dlname if we got it. it's perfectly good, no?
+	    if test -n "$dlname"; then
+	      soname=$dlname
+	    elif test -n "$soname_spec"; then
+	      # bleh windows
+	      case $host in
+	      *cygwin* | mingw* | *cegcc* | *os2*)
+	        func_arith $current - $age
+		major=$func_arith_result
+		versuffix=-$major
+		;;
+	      esac
+	      eval soname=\"$soname_spec\"
+	    else
+	      soname=$realname
+	    fi
+
+	    # Make a new name for the extract_expsyms_cmds to use
+	    soroot=$soname
+	    func_basename "$soroot"
+	    soname=$func_basename_result
+	    func_stripname 'lib' '.dll' "$soname"
+	    newlib=libimp-$func_stripname_result.a
+
+	    # If the library has no export list, then create one now
+	    if test -f "$output_objdir/$soname-def"; then :
+	    else
+	      func_verbose "extracting exported symbol list from '$soname'"
+	      func_execute_cmds "$extract_expsyms_cmds" 'exit $?'
+	    fi
+
+	    # Create $newlib
+	    if test -f "$output_objdir/$newlib"; then :; else
+	      func_verbose "generating import library for '$soname'"
+	      func_execute_cmds "$old_archive_from_expsyms_cmds" 'exit $?'
+	    fi
+	    # make sure the library variables are pointing to the new library
+	    dir=$output_objdir
+	    linklib=$newlib
+	  fi # test -n "$old_archive_from_expsyms_cmds"
+
+	  if test prog = "$linkmode" || test relink != "$opt_mode"; then
+	    add_shlibpath=
+	    add_dir=
+	    add=
+	    lib_linked=yes
+	    case $hardcode_action in
+	    immediate | unsupported)
+	      if test no = "$hardcode_direct"; then
+		add=$dir/$linklib
+		case $host in
+		  *-*-sco3.2v5.0.[024]*) add_dir=-L$dir ;;
+		  *-*-sysv4*uw2*) add_dir=-L$dir ;;
+		  *-*-sysv5OpenUNIX* | *-*-sysv5UnixWare7.[01].[10]* | \
+		    *-*-unixware7*) add_dir=-L$dir ;;
+		  *-*-darwin* )
+		    # if the lib is a (non-dlopened) module then we cannot
+		    # link against it, someone is ignoring the earlier warnings
+		    if /usr/bin/file -L $add 2> /dev/null |
+			 $GREP ": [^:]* bundle" >/dev/null; then
+		      if test "X$dlopenmodule" != "X$lib"; then
+			$ECHO "*** Warning: lib $linklib is a module, not a shared library"
+			if test -z "$old_library"; then
+			  echo
+			  echo "*** And there doesn't seem to be a static archive available"
+			  echo "*** The link will probably fail, sorry"
+			else
+			  add=$dir/$old_library
+			fi
+		      elif test -n "$old_library"; then
+			add=$dir/$old_library
+		      fi
+		    fi
+		esac
+	      elif test no = "$hardcode_minus_L"; then
+		case $host in
+		*-*-sunos*) add_shlibpath=$dir ;;
+		esac
+		add_dir=-L$dir
+		add=-l$name
+	      elif test no = "$hardcode_shlibpath_var"; then
+		add_shlibpath=$dir
+		add=-l$name
+	      else
+		lib_linked=no
+	      fi
+	      ;;
+	    relink)
+	      if test yes = "$hardcode_direct" &&
+	         test no = "$hardcode_direct_absolute"; then
+		add=$dir/$linklib
+	      elif test yes = "$hardcode_minus_L"; then
+		add_dir=-L$absdir
+		# Try looking first in the location we're being installed to.
+		if test -n "$inst_prefix_dir"; then
+		  case $libdir in
+		    [\\/]*)
+		      func_append add_dir " -L$inst_prefix_dir$libdir"
+		      ;;
+		  esac
+		fi
+		add=-l$name
+	      elif test yes = "$hardcode_shlibpath_var"; then
+		add_shlibpath=$dir
+		add=-l$name
+	      else
+		lib_linked=no
+	      fi
+	      ;;
+	    *) lib_linked=no ;;
+	    esac
+
+	    if test yes != "$lib_linked"; then
+	      func_fatal_configuration "unsupported hardcode properties"
+	    fi
+
+	    if test -n "$add_shlibpath"; then
+	      case :$compile_shlibpath: in
+	      *":$add_shlibpath:"*) ;;
+	      *) func_append compile_shlibpath "$add_shlibpath:" ;;
+	      esac
+	    fi
+	    if test prog = "$linkmode"; then
+	      test -n "$add_dir" && compile_deplibs="$add_dir $compile_deplibs"
+	      test -n "$add" && compile_deplibs="$add $compile_deplibs"
+	    else
+	      test -n "$add_dir" && deplibs="$add_dir $deplibs"
+	      test -n "$add" && deplibs="$add $deplibs"
+	      if test yes != "$hardcode_direct" &&
+		 test yes != "$hardcode_minus_L" &&
+		 test yes = "$hardcode_shlibpath_var"; then
+		case :$finalize_shlibpath: in
+		*":$libdir:"*) ;;
+		*) func_append finalize_shlibpath "$libdir:" ;;
+		esac
+	      fi
+	    fi
+	  fi
+
+	  if test prog = "$linkmode" || test relink = "$opt_mode"; then
+	    add_shlibpath=
+	    add_dir=
+	    add=
+	    # Finalize command for both is simple: just hardcode it.
+	    if test yes = "$hardcode_direct" &&
+	       test no = "$hardcode_direct_absolute"; then
+	      add=$libdir/$linklib
+	    elif test yes = "$hardcode_minus_L"; then
+	      add_dir=-L$libdir
+	      add=-l$name
+	    elif test yes = "$hardcode_shlibpath_var"; then
+	      case :$finalize_shlibpath: in
+	      *":$libdir:"*) ;;
+	      *) func_append finalize_shlibpath "$libdir:" ;;
+	      esac
+	      add=-l$name
+	    elif test yes = "$hardcode_automatic"; then
+	      if test -n "$inst_prefix_dir" &&
+		 test -f "$inst_prefix_dir$libdir/$linklib"; then
+		add=$inst_prefix_dir$libdir/$linklib
+	      else
+		add=$libdir/$linklib
+	      fi
+	    else
+	      # We cannot seem to hardcode it, guess we'll fake it.
+	      add_dir=-L$libdir
+	      # Try looking first in the location we're being installed to.
+	      if test -n "$inst_prefix_dir"; then
+		case $libdir in
+		  [\\/]*)
+		    func_append add_dir " -L$inst_prefix_dir$libdir"
+		    ;;
+		esac
+	      fi
+	      add=-l$name
+	    fi
+
+	    if test prog = "$linkmode"; then
+	      test -n "$add_dir" && finalize_deplibs="$add_dir $finalize_deplibs"
+	      test -n "$add" && finalize_deplibs="$add $finalize_deplibs"
+	    else
+	      test -n "$add_dir" && deplibs="$add_dir $deplibs"
+	      test -n "$add" && deplibs="$add $deplibs"
+	    fi
+	  fi
+	elif test prog = "$linkmode"; then
+	  # Here we assume that one of hardcode_direct or hardcode_minus_L
+	  # is not unsupported.  This is valid on all known static and
+	  # shared platforms.
+	  if test unsupported != "$hardcode_direct"; then
+	    test -n "$old_library" && linklib=$old_library
+	    compile_deplibs="$dir/$linklib $compile_deplibs"
+	    finalize_deplibs="$dir/$linklib $finalize_deplibs"
+	  else
+	    compile_deplibs="-l$name -L$dir $compile_deplibs"
+	    finalize_deplibs="-l$name -L$dir $finalize_deplibs"
+	  fi
+	elif test yes = "$build_libtool_libs"; then
+	  # Not a shared library
+	  if test pass_all != "$deplibs_check_method"; then
+	    # We're trying link a shared library against a static one
+	    # but the system doesn't support it.
+
+	    # Just print a warning and add the library to dependency_libs so
+	    # that the program can be linked against the static library.
+	    echo
+	    $ECHO "*** Warning: This system cannot link to static lib archive $lib."
+	    echo "*** I have the capability to make that library automatically link in when"
+	    echo "*** you link to this library.  But I can only do this if you have a"
+	    echo "*** shared version of the library, which you do not appear to have."
+	    if test yes = "$module"; then
+	      echo "*** But as you try to build a module library, libtool will still create "
+	      echo "*** a static module, that should work as long as the dlopening application"
+	      echo "*** is linked with the -dlopen flag to resolve symbols at runtime."
+	      if test -z "$global_symbol_pipe"; then
+		echo
+		echo "*** However, this would only work if libtool was able to extract symbol"
+		echo "*** lists from a program, using 'nm' or equivalent, but libtool could"
+		echo "*** not find such a program.  So, this module is probably useless."
+		echo "*** 'nm' from GNU binutils and a full rebuild may help."
+	      fi
+	      if test no = "$build_old_libs"; then
+		build_libtool_libs=module
+		build_old_libs=yes
+	      else
+		build_libtool_libs=no
+	      fi
+	    fi
+	  else
+	    deplibs="$dir/$old_library $deplibs"
+	    link_static=yes
+	  fi
+	fi # link shared/static library?
+
+	if test lib = "$linkmode"; then
+	  if test -n "$dependency_libs" &&
+	     { test yes != "$hardcode_into_libs" ||
+	       test yes = "$build_old_libs" ||
+	       test yes = "$link_static"; }; then
+	    # Extract -R from dependency_libs
+	    temp_deplibs=
+	    for libdir in $dependency_libs; do
+	      case $libdir in
+	      -R*) func_stripname '-R' '' "$libdir"
+	           temp_xrpath=$func_stripname_result
+		   case " $xrpath " in
+		   *" $temp_xrpath "*) ;;
+		   *) func_append xrpath " $temp_xrpath";;
+		   esac;;
+	      *) func_append temp_deplibs " $libdir";;
+	      esac
+	    done
+	    dependency_libs=$temp_deplibs
+	  fi
+
+	  func_append newlib_search_path " $absdir"
+	  # Link against this library
+	  test no = "$link_static" && newdependency_libs="$abs_ladir/$laname $newdependency_libs"
+	  # ... and its dependency_libs
+	  tmp_libs=
+	  for deplib in $dependency_libs; do
+	    newdependency_libs="$deplib $newdependency_libs"
+	    case $deplib in
+              -L*) func_stripname '-L' '' "$deplib"
+                   func_resolve_sysroot "$func_stripname_result";;
+              *) func_resolve_sysroot "$deplib" ;;
+            esac
+	    if $opt_preserve_dup_deps; then
+	      case "$tmp_libs " in
+	      *" $func_resolve_sysroot_result "*)
+                func_append specialdeplibs " $func_resolve_sysroot_result" ;;
+	      esac
+	    fi
+	    func_append tmp_libs " $func_resolve_sysroot_result"
+	  done
+
+	  if test no != "$link_all_deplibs"; then
+	    # Add the search paths of all dependency libraries
+	    for deplib in $dependency_libs; do
+	      path=
+	      case $deplib in
+	      -L*) path=$deplib ;;
+	      *.la)
+	        func_resolve_sysroot "$deplib"
+	        deplib=$func_resolve_sysroot_result
+	        func_dirname "$deplib" "" "."
+		dir=$func_dirname_result
+		# We need an absolute path.
+		case $dir in
+		[\\/]* | [A-Za-z]:[\\/]*) absdir=$dir ;;
+		*)
+		  absdir=`cd "$dir" && pwd`
+		  if test -z "$absdir"; then
+		    func_warning "cannot determine absolute directory name of '$dir'"
+		    absdir=$dir
+		  fi
+		  ;;
+		esac
+		if $GREP "^installed=no" $deplib > /dev/null; then
+		case $host in
+		*-*-darwin*)
+		  depdepl=
+		  eval deplibrary_names=`$SED -n -e 's/^library_names=\(.*\)$/\1/p' $deplib`
+		  if test -n "$deplibrary_names"; then
+		    for tmp in $deplibrary_names; do
+		      depdepl=$tmp
+		    done
+		    if test -f "$absdir/$objdir/$depdepl"; then
+		      depdepl=$absdir/$objdir/$depdepl
+		      darwin_install_name=`$OTOOL -L $depdepl | awk '{if (NR == 2) {print $1;exit}}'`
+                      if test -z "$darwin_install_name"; then
+                          darwin_install_name=`$OTOOL64 -L $depdepl  | awk '{if (NR == 2) {print $1;exit}}'`
+                      fi
+		      func_append compiler_flags " $wl-dylib_file $wl$darwin_install_name:$depdepl"
+		      func_append linker_flags " -dylib_file $darwin_install_name:$depdepl"
+		      path=
+		    fi
+		  fi
+		  ;;
+		*)
+		  path=-L$absdir/$objdir
+		  ;;
+		esac
+		else
+		  eval libdir=`$SED -n -e 's/^libdir=\(.*\)$/\1/p' $deplib`
+		  test -z "$libdir" && \
+		    func_fatal_error "'$deplib' is not a valid libtool archive"
+		  test "$absdir" != "$libdir" && \
+		    func_warning "'$deplib' seems to be moved"
+
+		  path=-L$absdir
+		fi
+		;;
+	      esac
+	      case " $deplibs " in
+	      *" $path "*) ;;
+	      *) deplibs="$path $deplibs" ;;
+	      esac
+	    done
+	  fi # link_all_deplibs != no
+	fi # linkmode = lib
+      done # for deplib in $libs
+      if test link = "$pass"; then
+	if test prog = "$linkmode"; then
+	  compile_deplibs="$new_inherited_linker_flags $compile_deplibs"
+	  finalize_deplibs="$new_inherited_linker_flags $finalize_deplibs"
+	else
+	  compiler_flags="$compiler_flags "`$ECHO " $new_inherited_linker_flags" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	fi
+      fi
+      dependency_libs=$newdependency_libs
+      if test dlpreopen = "$pass"; then
+	# Link the dlpreopened libraries before other libraries
+	for deplib in $save_deplibs; do
+	  deplibs="$deplib $deplibs"
+	done
+      fi
+      if test dlopen != "$pass"; then
+	test conv = "$pass" || {
+	  # Make sure lib_search_path contains only unique directories.
+	  lib_search_path=
+	  for dir in $newlib_search_path; do
+	    case "$lib_search_path " in
+	    *" $dir "*) ;;
+	    *) func_append lib_search_path " $dir" ;;
+	    esac
+	  done
+	  newlib_search_path=
+	}
+
+	if test prog,link = "$linkmode,$pass"; then
+	  vars="compile_deplibs finalize_deplibs"
+	else
+	  vars=deplibs
+	fi
+	for var in $vars dependency_libs; do
+	  # Add libraries to $var in reverse order
+	  eval tmp_libs=\"\$$var\"
+	  new_libs=
+	  for deplib in $tmp_libs; do
+	    # FIXME: Pedantically, this is the right thing to do, so
+	    #        that some nasty dependency loop isn't accidentally
+	    #        broken:
+	    #new_libs="$deplib $new_libs"
+	    # Pragmatically, this seems to cause very few problems in
+	    # practice:
+	    case $deplib in
+	    -L*) new_libs="$deplib $new_libs" ;;
+	    -R*) ;;
+	    *)
+	      # And here is the reason: when a library appears more
+	      # than once as an explicit dependence of a library, or
+	      # is implicitly linked in more than once by the
+	      # compiler, it is considered special, and multiple
+	      # occurrences thereof are not removed.  Compare this
+	      # with having the same library being listed as a
+	      # dependency of multiple other libraries: in this case,
+	      # we know (pedantically, we assume) the library does not
+	      # need to be listed more than once, so we keep only the
+	      # last copy.  This is not always right, but it is rare
+	      # enough that we require users that really mean to play
+	      # such unportable linking tricks to link the library
+	      # using -Wl,-lname, so that libtool does not consider it
+	      # for duplicate removal.
+	      case " $specialdeplibs " in
+	      *" $deplib "*) new_libs="$deplib $new_libs" ;;
+	      *)
+		case " $new_libs " in
+		*" $deplib "*) ;;
+		*) new_libs="$deplib $new_libs" ;;
+		esac
+		;;
+	      esac
+	      ;;
+	    esac
+	  done
+	  tmp_libs=
+	  for deplib in $new_libs; do
+	    case $deplib in
+	    -L*)
+	      case " $tmp_libs " in
+	      *" $deplib "*) ;;
+	      *) func_append tmp_libs " $deplib" ;;
+	      esac
+	      ;;
+	    *) func_append tmp_libs " $deplib" ;;
+	    esac
+	  done
+	  eval $var=\"$tmp_libs\"
+	done # for var
+      fi
+
+      # Add Sun CC postdeps if required:
+      test CXX = "$tagname" && {
+        case $host_os in
+        linux*)
+          case `$CC -V 2>&1 | sed 5q` in
+          *Sun\ C*) # Sun C++ 5.9
+            func_suncc_cstd_abi
+
+            if test no != "$suncc_use_cstd_abi"; then
+              func_append postdeps ' -library=Cstd -library=Crun'
+            fi
+            ;;
+          esac
+          ;;
+
+        solaris*)
+          func_cc_basename "$CC"
+          case $func_cc_basename_result in
+          CC* | sunCC*)
+            func_suncc_cstd_abi
+
+            if test no != "$suncc_use_cstd_abi"; then
+              func_append postdeps ' -library=Cstd -library=Crun'
+            fi
+            ;;
+          esac
+          ;;
+        esac
+      }
+
+      # Last step: remove runtime libs from dependency_libs
+      # (they stay in deplibs)
+      tmp_libs=
+      for i in $dependency_libs; do
+	case " $predeps $postdeps $compiler_lib_search_path " in
+	*" $i "*)
+	  i=
+	  ;;
+	esac
+	if test -n "$i"; then
+	  func_append tmp_libs " $i"
+	fi
+      done
+      dependency_libs=$tmp_libs
+    done # for pass
+    if test prog = "$linkmode"; then
+      dlfiles=$newdlfiles
+    fi
+    if test prog = "$linkmode" || test lib = "$linkmode"; then
+      dlprefiles=$newdlprefiles
+    fi
+
+    case $linkmode in
+    oldlib)
+      if test -n "$dlfiles$dlprefiles" || test no != "$dlself"; then
+	func_warning "'-dlopen' is ignored for archives"
+      fi
+
+      case " $deplibs" in
+      *\ -l* | *\ -L*)
+	func_warning "'-l' and '-L' are ignored for archives" ;;
+      esac
+
+      test -n "$rpath" && \
+	func_warning "'-rpath' is ignored for archives"
+
+      test -n "$xrpath" && \
+	func_warning "'-R' is ignored for archives"
+
+      test -n "$vinfo" && \
+	func_warning "'-version-info/-version-number' is ignored for archives"
+
+      test -n "$release" && \
+	func_warning "'-release' is ignored for archives"
+
+      test -n "$export_symbols$export_symbols_regex" && \
+	func_warning "'-export-symbols' is ignored for archives"
+
+      # Now set the variables for building old libraries.
+      build_libtool_libs=no
+      oldlibs=$output
+      func_append objs "$old_deplibs"
+      ;;
+
+    lib)
+      # Make sure we only generate libraries of the form 'libNAME.la'.
+      case $outputname in
+      lib*)
+	func_stripname 'lib' '.la' "$outputname"
+	name=$func_stripname_result
+	eval shared_ext=\"$shrext_cmds\"
+	eval libname=\"$libname_spec\"
+	;;
+      *)
+	test no = "$module" \
+	  && func_fatal_help "libtool library '$output' must begin with 'lib'"
+
+	if test no != "$need_lib_prefix"; then
+	  # Add the "lib" prefix for modules if required
+	  func_stripname '' '.la' "$outputname"
+	  name=$func_stripname_result
+	  eval shared_ext=\"$shrext_cmds\"
+	  eval libname=\"$libname_spec\"
+	else
+	  func_stripname '' '.la' "$outputname"
+	  libname=$func_stripname_result
+	fi
+	;;
+      esac
+
+      if test -n "$objs"; then
+	if test pass_all != "$deplibs_check_method"; then
+	  func_fatal_error "cannot build libtool library '$output' from non-libtool objects on this host:$objs"
+	else
+	  echo
+	  $ECHO "*** Warning: Linking the shared library $output against the non-libtool"
+	  $ECHO "*** objects $objs is not portable!"
+	  func_append libobjs " $objs"
+	fi
+      fi
+
+      test no = "$dlself" \
+	|| func_warning "'-dlopen self' is ignored for libtool libraries"
+
+      set dummy $rpath
+      shift
+      test 1 -lt "$#" \
+	&& func_warning "ignoring multiple '-rpath's for a libtool library"
+
+      install_libdir=$1
+
+      oldlibs=
+      if test -z "$rpath"; then
+	if test yes = "$build_libtool_libs"; then
+	  # Building a libtool convenience library.
+	  # Some compilers have problems with a '.al' extension so
+	  # convenience libraries should have the same extension an
+	  # archive normally would.
+	  oldlibs="$output_objdir/$libname.$libext $oldlibs"
+	  build_libtool_libs=convenience
+	  build_old_libs=yes
+	fi
+
+	test -n "$vinfo" && \
+	  func_warning "'-version-info/-version-number' is ignored for convenience libraries"
+
+	test -n "$release" && \
+	  func_warning "'-release' is ignored for convenience libraries"
+      else
+
+	# Parse the version information argument.
+	save_ifs=$IFS; IFS=:
+	set dummy $vinfo 0 0 0
+	shift
+	IFS=$save_ifs
+
+	test -n "$7" && \
+	  func_fatal_help "too many parameters to '-version-info'"
+
+	# convert absolute version numbers to libtool ages
+	# this retains compatibility with .la files and attempts
+	# to make the code below a bit more comprehensible
+
+	case $vinfo_number in
+	yes)
+	  number_major=$1
+	  number_minor=$2
+	  number_revision=$3
+	  #
+	  # There are really only two kinds -- those that
+	  # use the current revision as the major version
+	  # and those that subtract age and use age as
+	  # a minor version.  But, then there is irix
+	  # that has an extra 1 added just for fun
+	  #
+	  case $version_type in
+	  # correct linux to gnu/linux during the next big refactor
+	  darwin|freebsd-elf|linux|osf|windows|none)
+	    func_arith $number_major + $number_minor
+	    current=$func_arith_result
+	    age=$number_minor
+	    revision=$number_revision
+	    ;;
+	  freebsd-aout|qnx|sunos)
+	    current=$number_major
+	    revision=$number_minor
+	    age=0
+	    ;;
+	  irix|nonstopux)
+	    func_arith $number_major + $number_minor
+	    current=$func_arith_result
+	    age=$number_minor
+	    revision=$number_minor
+	    lt_irix_increment=no
+	    ;;
+	  esac
+	  ;;
+	no)
+	  current=$1
+	  revision=$2
+	  age=$3
+	  ;;
+	esac
+
+	# Check that each of the things are valid numbers.
+	case $current in
+	0|[1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9][0-9][0-9]) ;;
+	*)
+	  func_error "CURRENT '$current' must be a nonnegative integer"
+	  func_fatal_error "'$vinfo' is not valid version information"
+	  ;;
+	esac
+
+	case $revision in
+	0|[1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9][0-9][0-9]) ;;
+	*)
+	  func_error "REVISION '$revision' must be a nonnegative integer"
+	  func_fatal_error "'$vinfo' is not valid version information"
+	  ;;
+	esac
+
+	case $age in
+	0|[1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9][0-9][0-9]) ;;
+	*)
+	  func_error "AGE '$age' must be a nonnegative integer"
+	  func_fatal_error "'$vinfo' is not valid version information"
+	  ;;
+	esac
+
+	if test "$age" -gt "$current"; then
+	  func_error "AGE '$age' is greater than the current interface number '$current'"
+	  func_fatal_error "'$vinfo' is not valid version information"
+	fi
+
+	# Calculate the version variables.
+	major=
+	versuffix=
+	verstring=
+	case $version_type in
+	none) ;;
+
+	darwin)
+	  # Like Linux, but with the current version available in
+	  # verstring for coding it into the library header
+	  func_arith $current - $age
+	  major=.$func_arith_result
+	  versuffix=$major.$age.$revision
+	  # Darwin ld doesn't like 0 for these options...
+	  func_arith $current + 1
+	  minor_current=$func_arith_result
+	  xlcverstring="$wl-compatibility_version $wl$minor_current $wl-current_version $wl$minor_current.$revision"
+	  verstring="-compatibility_version $minor_current -current_version $minor_current.$revision"
+          # On Darwin other compilers
+          case $CC in
+              nagfor*)
+                  verstring="$wl-compatibility_version $wl$minor_current $wl-current_version $wl$minor_current.$revision"
+                  ;;
+              *)
+                  verstring="-compatibility_version $minor_current -current_version $minor_current.$revision"
+                  ;;
+          esac
+	  ;;
+
+	freebsd-aout)
+	  major=.$current
+	  versuffix=.$current.$revision
+	  ;;
+
+	freebsd-elf)
+	  func_arith $current - $age
+	  major=.$func_arith_result
+	  versuffix=$major.$age.$revision
+	  ;;
+
+	irix | nonstopux)
+	  if test no = "$lt_irix_increment"; then
+	    func_arith $current - $age
+	  else
+	    func_arith $current - $age + 1
+	  fi
+	  major=$func_arith_result
+
+	  case $version_type in
+	    nonstopux) verstring_prefix=nonstopux ;;
+	    *)         verstring_prefix=sgi ;;
+	  esac
+	  verstring=$verstring_prefix$major.$revision
+
+	  # Add in all the interfaces that we are compatible with.
+	  loop=$revision
+	  while test 0 -ne "$loop"; do
+	    func_arith $revision - $loop
+	    iface=$func_arith_result
+	    func_arith $loop - 1
+	    loop=$func_arith_result
+	    verstring=$verstring_prefix$major.$iface:$verstring
+	  done
+
+	  # Before this point, $major must not contain '.'.
+	  major=.$major
+	  versuffix=$major.$revision
+	  ;;
+
+	linux) # correct to gnu/linux during the next big refactor
+	  func_arith $current - $age
+	  major=.$func_arith_result
+	  versuffix=$major.$age.$revision
+	  ;;
+
+	osf)
+	  func_arith $current - $age
+	  major=.$func_arith_result
+	  versuffix=.$current.$age.$revision
+	  verstring=$current.$age.$revision
+
+	  # Add in all the interfaces that we are compatible with.
+	  loop=$age
+	  while test 0 -ne "$loop"; do
+	    func_arith $current - $loop
+	    iface=$func_arith_result
+	    func_arith $loop - 1
+	    loop=$func_arith_result
+	    verstring=$verstring:$iface.0
+	  done
+
+	  # Make executables depend on our current version.
+	  func_append verstring ":$current.0"
+	  ;;
+
+	qnx)
+	  major=.$current
+	  versuffix=.$current
+	  ;;
+
+	sco)
+	  major=.$current
+	  versuffix=.$current
+	  ;;
+
+	sunos)
+	  major=.$current
+	  versuffix=.$current.$revision
+	  ;;
+
+	windows)
+	  # Use '-' rather than '.', since we only want one
+	  # extension on DOS 8.3 file systems.
+	  func_arith $current - $age
+	  major=$func_arith_result
+	  versuffix=-$major
+	  ;;
+
+	*)
+	  func_fatal_configuration "unknown library version type '$version_type'"
+	  ;;
+	esac
+
+	# Clear the version info if we defaulted, and they specified a release.
+	if test -z "$vinfo" && test -n "$release"; then
+	  major=
+	  case $version_type in
+	  darwin)
+	    # we can't check for "0.0" in archive_cmds due to quoting
+	    # problems, so we reset it completely
+	    verstring=
+	    ;;
+	  *)
+	    verstring=0.0
+	    ;;
+	  esac
+	  if test no = "$need_version"; then
+	    versuffix=
+	  else
+	    versuffix=.0.0
+	  fi
+	fi
+
+	# Remove version info from name if versioning should be avoided
+	if test yes,no = "$avoid_version,$need_version"; then
+	  major=
+	  versuffix=
+	  verstring=
+	fi
+
+	# Check to see if the archive will have undefined symbols.
+	if test yes = "$allow_undefined"; then
+	  if test unsupported = "$allow_undefined_flag"; then
+	    if test yes = "$build_old_libs"; then
+	      func_warning "undefined symbols not allowed in $host shared libraries; building static only"
+	      build_libtool_libs=no
+	    else
+	      func_fatal_error "can't build $host shared library unless -no-undefined is specified"
+	    fi
+	  fi
+	else
+	  # Don't allow undefined symbols.
+	  allow_undefined_flag=$no_undefined_flag
+	fi
+
+      fi
+
+      func_generate_dlsyms "$libname" "$libname" :
+      func_append libobjs " $symfileobj"
+      test " " = "$libobjs" && libobjs=
+
+      if test relink != "$opt_mode"; then
+	# Remove our outputs, but don't remove object files since they
+	# may have been created when compiling PIC objects.
+	removelist=
+	tempremovelist=`$ECHO "$output_objdir/*"`
+	for p in $tempremovelist; do
+	  case $p in
+	    *.$objext | *.gcno)
+	       ;;
+	    $output_objdir/$outputname | $output_objdir/$libname.* | $output_objdir/$libname$release.*)
+	       if test -n "$precious_files_regex"; then
+		 if $ECHO "$p" | $EGREP -e "$precious_files_regex" >/dev/null 2>&1
+		 then
+		   continue
+		 fi
+	       fi
+	       func_append removelist " $p"
+	       ;;
+	    *) ;;
+	  esac
+	done
+	test -n "$removelist" && \
+	  func_show_eval "${RM}r \$removelist"
+      fi
+
+      # Now set the variables for building old libraries.
+      if test yes = "$build_old_libs" && test convenience != "$build_libtool_libs"; then
+	func_append oldlibs " $output_objdir/$libname.$libext"
+
+	# Transform .lo files to .o files.
+	oldobjs="$objs "`$ECHO "$libobjs" | $SP2NL | $SED "/\.$libext$/d; $lo2o" | $NL2SP`
+      fi
+
+      # Eliminate all temporary directories.
+      #for path in $notinst_path; do
+      #	lib_search_path=`$ECHO "$lib_search_path " | $SED "s% $path % %g"`
+      #	deplibs=`$ECHO "$deplibs " | $SED "s% -L$path % %g"`
+      #	dependency_libs=`$ECHO "$dependency_libs " | $SED "s% -L$path % %g"`
+      #done
+
+      if test -n "$xrpath"; then
+	# If the user specified any rpath flags, then add them.
+	temp_xrpath=
+	for libdir in $xrpath; do
+	  func_replace_sysroot "$libdir"
+	  func_append temp_xrpath " -R$func_replace_sysroot_result"
+	  case "$finalize_rpath " in
+	  *" $libdir "*) ;;
+	  *) func_append finalize_rpath " $libdir" ;;
+	  esac
+	done
+	if test yes != "$hardcode_into_libs" || test yes = "$build_old_libs"; then
+	  dependency_libs="$temp_xrpath $dependency_libs"
+	fi
+      fi
+
+      # Make sure dlfiles contains only unique files that won't be dlpreopened
+      old_dlfiles=$dlfiles
+      dlfiles=
+      for lib in $old_dlfiles; do
+	case " $dlprefiles $dlfiles " in
+	*" $lib "*) ;;
+	*) func_append dlfiles " $lib" ;;
+	esac
+      done
+
+      # Make sure dlprefiles contains only unique files
+      old_dlprefiles=$dlprefiles
+      dlprefiles=
+      for lib in $old_dlprefiles; do
+	case "$dlprefiles " in
+	*" $lib "*) ;;
+	*) func_append dlprefiles " $lib" ;;
+	esac
+      done
+
+      if test yes = "$build_libtool_libs"; then
+	if test -n "$rpath"; then
+	  case $host in
+	  *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-beos* | *-cegcc* | *-*-haiku*)
+	    # these systems don't actually have a c library (as such)!
+	    ;;
+	  *-*-rhapsody* | *-*-darwin1.[012])
+	    # Rhapsody C library is in the System framework
+	    func_append deplibs " System.ltframework"
+	    ;;
+	  *-*-netbsd*)
+	    # Don't link with libc until the a.out ld.so is fixed.
+	    ;;
+	  *-*-openbsd* | *-*-freebsd* | *-*-dragonfly*)
+	    # Do not include libc due to us having libc/libc_r.
+	    ;;
+	  *-*-sco3.2v5* | *-*-sco5v6*)
+	    # Causes problems with __ctype
+	    ;;
+	  *-*-sysv4.2uw2* | *-*-sysv5* | *-*-unixware* | *-*-OpenUNIX*)
+	    # Compiler inserts libc in the correct place for threads to work
+	    ;;
+	  *)
+	    # Add libc to deplibs on all other systems if necessary.
+	    if test yes = "$build_libtool_need_lc"; then
+	      func_append deplibs " -lc"
+	    fi
+	    ;;
+	  esac
+	fi
+
+	# Transform deplibs into only deplibs that can be linked in shared.
+	name_save=$name
+	libname_save=$libname
+	release_save=$release
+	versuffix_save=$versuffix
+	major_save=$major
+	# I'm not sure if I'm treating the release correctly.  I think
+	# release should show up in the -l (ie -lgmp5) so we don't want to
+	# add it in twice.  Is that correct?
+	release=
+	versuffix=
+	major=
+	newdeplibs=
+	droppeddeps=no
+	case $deplibs_check_method in
+	pass_all)
+	  # Don't check for shared/static.  Everything works.
+	  # This might be a little naive.  We might want to check
+	  # whether the library exists or not.  But this is on
+	  # osf3 & osf4 and I'm not really sure... Just
+	  # implementing what was already the behavior.
+	  newdeplibs=$deplibs
+	  ;;
+	test_compile)
+	  # This code stresses the "libraries are programs" paradigm to its
+	  # limits. Maybe even breaks it.  We compile a program, linking it
+	  # against the deplibs as a proxy for the library.  Then we can check
+	  # whether they linked in statically or dynamically with ldd.
+	  $opt_dry_run || $RM conftest.c
+	  cat > conftest.c <<EOF
+	  int main() { return 0; }
+EOF
+	  $opt_dry_run || $RM conftest
+	  if $LTCC $LTCFLAGS -o conftest conftest.c $deplibs; then
+	    ldd_output=`ldd conftest`
+	    for i in $deplibs; do
+	      case $i in
+	      -l*)
+		func_stripname -l '' "$i"
+		name=$func_stripname_result
+		if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+		  case " $predeps $postdeps " in
+		  *" $i "*)
+		    func_append newdeplibs " $i"
+		    i=
+		    ;;
+		  esac
+		fi
+		if test -n "$i"; then
+		  libname=`eval "\\$ECHO \"$libname_spec\""`
+		  deplib_matches=`eval "\\$ECHO \"$library_names_spec\""`
+		  set dummy $deplib_matches; shift
+		  deplib_match=$1
+		  if test `expr "$ldd_output" : ".*$deplib_match"` -ne 0; then
+		    func_append newdeplibs " $i"
+		  else
+		    droppeddeps=yes
+		    echo
+		    $ECHO "*** Warning: dynamic linker does not accept needed library $i."
+		    echo "*** I have the capability to make that library automatically link in when"
+		    echo "*** you link to this library.  But I can only do this if you have a"
+		    echo "*** shared version of the library, which I believe you do not have"
+		    echo "*** because a test_compile did reveal that the linker did not use it for"
+		    echo "*** its dynamic dependency list that programs get resolved with at runtime."
+		  fi
+		fi
+		;;
+	      *)
+		func_append newdeplibs " $i"
+		;;
+	      esac
+	    done
+	  else
+	    # Error occurred in the first compile.  Let's try to salvage
+	    # the situation: Compile a separate program for each library.
+	    for i in $deplibs; do
+	      case $i in
+	      -l*)
+		func_stripname -l '' "$i"
+		name=$func_stripname_result
+		$opt_dry_run || $RM conftest
+		if $LTCC $LTCFLAGS -o conftest conftest.c $i; then
+		  ldd_output=`ldd conftest`
+		  if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+		    case " $predeps $postdeps " in
+		    *" $i "*)
+		      func_append newdeplibs " $i"
+		      i=
+		      ;;
+		    esac
+		  fi
+		  if test -n "$i"; then
+		    libname=`eval "\\$ECHO \"$libname_spec\""`
+		    deplib_matches=`eval "\\$ECHO \"$library_names_spec\""`
+		    set dummy $deplib_matches; shift
+		    deplib_match=$1
+		    if test `expr "$ldd_output" : ".*$deplib_match"` -ne 0; then
+		      func_append newdeplibs " $i"
+		    else
+		      droppeddeps=yes
+		      echo
+		      $ECHO "*** Warning: dynamic linker does not accept needed library $i."
+		      echo "*** I have the capability to make that library automatically link in when"
+		      echo "*** you link to this library.  But I can only do this if you have a"
+		      echo "*** shared version of the library, which you do not appear to have"
+		      echo "*** because a test_compile did reveal that the linker did not use this one"
+		      echo "*** as a dynamic dependency that programs can get resolved with at runtime."
+		    fi
+		  fi
+		else
+		  droppeddeps=yes
+		  echo
+		  $ECHO "*** Warning!  Library $i is needed by this library but I was not able to"
+		  echo "*** make it link in!  You will probably need to install it or some"
+		  echo "*** library that it depends on before this library will be fully"
+		  echo "*** functional.  Installing it before continuing would be even better."
+		fi
+		;;
+	      *)
+		func_append newdeplibs " $i"
+		;;
+	      esac
+	    done
+	  fi
+	  ;;
+	file_magic*)
+	  set dummy $deplibs_check_method; shift
+	  file_magic_regex=`expr "$deplibs_check_method" : "$1 \(.*\)"`
+	  for a_deplib in $deplibs; do
+	    case $a_deplib in
+	    -l*)
+	      func_stripname -l '' "$a_deplib"
+	      name=$func_stripname_result
+	      if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+		case " $predeps $postdeps " in
+		*" $a_deplib "*)
+		  func_append newdeplibs " $a_deplib"
+		  a_deplib=
+		  ;;
+		esac
+	      fi
+	      if test -n "$a_deplib"; then
+		libname=`eval "\\$ECHO \"$libname_spec\""`
+		if test -n "$file_magic_glob"; then
+		  libnameglob=`func_echo_all "$libname" | $SED -e $file_magic_glob`
+		else
+		  libnameglob=$libname
+		fi
+		test yes = "$want_nocaseglob" && nocaseglob=`shopt -p nocaseglob`
+		for i in $lib_search_path $sys_lib_search_path $shlib_search_path; do
+		  if test yes = "$want_nocaseglob"; then
+		    shopt -s nocaseglob
+		    potential_libs=`ls $i/$libnameglob[.-]* 2>/dev/null`
+		    $nocaseglob
+		  else
+		    potential_libs=`ls $i/$libnameglob[.-]* 2>/dev/null`
+		  fi
+		  for potent_lib in $potential_libs; do
+		      # Follow soft links.
+		      if ls -lLd "$potent_lib" 2>/dev/null |
+			 $GREP " -> " >/dev/null; then
+			continue
+		      fi
+		      # The statement above tries to avoid entering an
+		      # endless loop below, in case of cyclic links.
+		      # We might still enter an endless loop, since a link
+		      # loop can be closed while we follow links,
+		      # but so what?
+		      potlib=$potent_lib
+		      while test -h "$potlib" 2>/dev/null; do
+			potliblink=`ls -ld $potlib | $SED 's/.* -> //'`
+			case $potliblink in
+			[\\/]* | [A-Za-z]:[\\/]*) potlib=$potliblink;;
+			*) potlib=`$ECHO "$potlib" | $SED 's|[^/]*$||'`"$potliblink";;
+			esac
+		      done
+		      if eval $file_magic_cmd \"\$potlib\" 2>/dev/null |
+			 $SED -e 10q |
+			 $EGREP "$file_magic_regex" > /dev/null; then
+			func_append newdeplibs " $a_deplib"
+			a_deplib=
+			break 2
+		      fi
+		  done
+		done
+	      fi
+	      if test -n "$a_deplib"; then
+		droppeddeps=yes
+		echo
+		$ECHO "*** Warning: linker path does not have real file for library $a_deplib."
+		echo "*** I have the capability to make that library automatically link in when"
+		echo "*** you link to this library.  But I can only do this if you have a"
+		echo "*** shared version of the library, which you do not appear to have"
+		echo "*** because I did check the linker path looking for a file starting"
+		if test -z "$potlib"; then
+		  $ECHO "*** with $libname but no candidates were found. (...for file magic test)"
+		else
+		  $ECHO "*** with $libname and none of the candidates passed a file format test"
+		  $ECHO "*** using a file magic. Last file checked: $potlib"
+		fi
+	      fi
+	      ;;
+	    *)
+	      # Add a -L argument.
+	      func_append newdeplibs " $a_deplib"
+	      ;;
+	    esac
+	  done # Gone through all deplibs.
+	  ;;
+	match_pattern*)
+	  set dummy $deplibs_check_method; shift
+	  match_pattern_regex=`expr "$deplibs_check_method" : "$1 \(.*\)"`
+	  for a_deplib in $deplibs; do
+	    case $a_deplib in
+	    -l*)
+	      func_stripname -l '' "$a_deplib"
+	      name=$func_stripname_result
+	      if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+		case " $predeps $postdeps " in
+		*" $a_deplib "*)
+		  func_append newdeplibs " $a_deplib"
+		  a_deplib=
+		  ;;
+		esac
+	      fi
+	      if test -n "$a_deplib"; then
+		libname=`eval "\\$ECHO \"$libname_spec\""`
+		for i in $lib_search_path $sys_lib_search_path $shlib_search_path; do
+		  potential_libs=`ls $i/$libname[.-]* 2>/dev/null`
+		  for potent_lib in $potential_libs; do
+		    potlib=$potent_lib # see symlink-check above in file_magic test
+		    if eval "\$ECHO \"$potent_lib\"" 2>/dev/null | $SED 10q | \
+		       $EGREP "$match_pattern_regex" > /dev/null; then
+		      func_append newdeplibs " $a_deplib"
+		      a_deplib=
+		      break 2
+		    fi
+		  done
+		done
+	      fi
+	      if test -n "$a_deplib"; then
+		droppeddeps=yes
+		echo
+		$ECHO "*** Warning: linker path does not have real file for library $a_deplib."
+		echo "*** I have the capability to make that library automatically link in when"
+		echo "*** you link to this library.  But I can only do this if you have a"
+		echo "*** shared version of the library, which you do not appear to have"
+		echo "*** because I did check the linker path looking for a file starting"
+		if test -z "$potlib"; then
+		  $ECHO "*** with $libname but no candidates were found. (...for regex pattern test)"
+		else
+		  $ECHO "*** with $libname and none of the candidates passed a file format test"
+		  $ECHO "*** using a regex pattern. Last file checked: $potlib"
+		fi
+	      fi
+	      ;;
+	    *)
+	      # Add a -L argument.
+	      func_append newdeplibs " $a_deplib"
+	      ;;
+	    esac
+	  done # Gone through all deplibs.
+	  ;;
+	none | unknown | *)
+	  newdeplibs=
+	  tmp_deplibs=`$ECHO " $deplibs" | $SED 's/ -lc$//; s/ -[LR][^ ]*//g'`
+	  if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+	    for i in $predeps $postdeps; do
+	      # can't use Xsed below, because $i might contain '/'
+	      tmp_deplibs=`$ECHO " $tmp_deplibs" | $SED "s|$i||"`
+	    done
+	  fi
+	  case $tmp_deplibs in
+	  *[!\	\ ]*)
+	    echo
+	    if test none = "$deplibs_check_method"; then
+	      echo "*** Warning: inter-library dependencies are not supported in this platform."
+	    else
+	      echo "*** Warning: inter-library dependencies are not known to be supported."
+	    fi
+	    echo "*** All declared inter-library dependencies are being dropped."
+	    droppeddeps=yes
+	    ;;
+	  esac
+	  ;;
+	esac
+	versuffix=$versuffix_save
+	major=$major_save
+	release=$release_save
+	libname=$libname_save
+	name=$name_save
+
+	case $host in
+	*-*-rhapsody* | *-*-darwin1.[012])
+	  # On Rhapsody replace the C library with the System framework
+	  newdeplibs=`$ECHO " $newdeplibs" | $SED 's/ -lc / System.ltframework /'`
+	  ;;
+	esac
+
+	if test yes = "$droppeddeps"; then
+	  if test yes = "$module"; then
+	    echo
+	    echo "*** Warning: libtool could not satisfy all declared inter-library"
+	    $ECHO "*** dependencies of module $libname.  Therefore, libtool will create"
+	    echo "*** a static module, that should work as long as the dlopening"
+	    echo "*** application is linked with the -dlopen flag."
+	    if test -z "$global_symbol_pipe"; then
+	      echo
+	      echo "*** However, this would only work if libtool was able to extract symbol"
+	      echo "*** lists from a program, using 'nm' or equivalent, but libtool could"
+	      echo "*** not find such a program.  So, this module is probably useless."
+	      echo "*** 'nm' from GNU binutils and a full rebuild may help."
+	    fi
+	    if test no = "$build_old_libs"; then
+	      oldlibs=$output_objdir/$libname.$libext
+	      build_libtool_libs=module
+	      build_old_libs=yes
+	    else
+	      build_libtool_libs=no
+	    fi
+	  else
+	    echo "*** The inter-library dependencies that have been dropped here will be"
+	    echo "*** automatically added whenever a program is linked with this library"
+	    echo "*** or is declared to -dlopen it."
+
+	    if test no = "$allow_undefined"; then
+	      echo
+	      echo "*** Since this library must not contain undefined symbols,"
+	      echo "*** because either the platform does not support them or"
+	      echo "*** it was explicitly requested with -no-undefined,"
+	      echo "*** libtool will only create a static version of it."
+	      if test no = "$build_old_libs"; then
+		oldlibs=$output_objdir/$libname.$libext
+		build_libtool_libs=module
+		build_old_libs=yes
+	      else
+		build_libtool_libs=no
+	      fi
+	    fi
+	  fi
+	fi
+	# Done checking deplibs!
+	deplibs=$newdeplibs
+      fi
+      # Time to change all our "foo.ltframework" stuff back to "-framework foo"
+      case $host in
+	*-*-darwin*)
+	  newdeplibs=`$ECHO " $newdeplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	  new_inherited_linker_flags=`$ECHO " $new_inherited_linker_flags" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	  deplibs=`$ECHO " $deplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	  ;;
+      esac
+
+      # move library search paths that coincide with paths to not yet
+      # installed libraries to the beginning of the library search list
+      new_libs=
+      for path in $notinst_path; do
+	case " $new_libs " in
+	*" -L$path/$objdir "*) ;;
+	*)
+	  case " $deplibs " in
+	  *" -L$path/$objdir "*)
+	    func_append new_libs " -L$path/$objdir" ;;
+	  esac
+	  ;;
+	esac
+      done
+      for deplib in $deplibs; do
+	case $deplib in
+	-L*)
+	  case " $new_libs " in
+	  *" $deplib "*) ;;
+	  *) func_append new_libs " $deplib" ;;
+	  esac
+	  ;;
+	*) func_append new_libs " $deplib" ;;
+	esac
+      done
+      deplibs=$new_libs
+
+      # All the library-specific variables (install_libdir is set above).
+      library_names=
+      old_library=
+      dlname=
+
+      # Test again, we may have decided not to build it any more
+      if test yes = "$build_libtool_libs"; then
+	# Remove $wl instances when linking with ld.
+	# FIXME: should test the right _cmds variable.
+	case $archive_cmds in
+	  *\$LD\ *) wl= ;;
+        esac
+	if test yes = "$hardcode_into_libs"; then
+	  # Hardcode the library paths
+	  hardcode_libdirs=
+	  dep_rpath=
+	  rpath=$finalize_rpath
+	  test relink = "$opt_mode" || rpath=$compile_rpath$rpath
+	  for libdir in $rpath; do
+	    if test -n "$hardcode_libdir_flag_spec"; then
+	      if test -n "$hardcode_libdir_separator"; then
+		func_replace_sysroot "$libdir"
+		libdir=$func_replace_sysroot_result
+		if test -z "$hardcode_libdirs"; then
+		  hardcode_libdirs=$libdir
+		else
+		  # Just accumulate the unique libdirs.
+		  case $hardcode_libdir_separator$hardcode_libdirs$hardcode_libdir_separator in
+		  *"$hardcode_libdir_separator$libdir$hardcode_libdir_separator"*)
+		    ;;
+		  *)
+		    func_append hardcode_libdirs "$hardcode_libdir_separator$libdir"
+		    ;;
+		  esac
+		fi
+	      else
+		eval flag=\"$hardcode_libdir_flag_spec\"
+		func_append dep_rpath " $flag"
+	      fi
+	    elif test -n "$runpath_var"; then
+	      case "$perm_rpath " in
+	      *" $libdir "*) ;;
+	      *) func_append perm_rpath " $libdir" ;;
+	      esac
+	    fi
+	  done
+	  # Substitute the hardcoded libdirs into the rpath.
+	  if test -n "$hardcode_libdir_separator" &&
+	     test -n "$hardcode_libdirs"; then
+	    libdir=$hardcode_libdirs
+	    eval "dep_rpath=\"$hardcode_libdir_flag_spec\""
+	  fi
+	  if test -n "$runpath_var" && test -n "$perm_rpath"; then
+	    # We should set the runpath_var.
+	    rpath=
+	    for dir in $perm_rpath; do
+	      func_append rpath "$dir:"
+	    done
+	    eval "$runpath_var='$rpath\$$runpath_var'; export $runpath_var"
+	  fi
+	  test -n "$dep_rpath" && deplibs="$dep_rpath $deplibs"
+	fi
+
+	shlibpath=$finalize_shlibpath
+	test relink = "$opt_mode" || shlibpath=$compile_shlibpath$shlibpath
+	if test -n "$shlibpath"; then
+	  eval "$shlibpath_var='$shlibpath\$$shlibpath_var'; export $shlibpath_var"
+	fi
+
+	# Get the real and link names of the library.
+	eval shared_ext=\"$shrext_cmds\"
+	eval library_names=\"$library_names_spec\"
+	set dummy $library_names
+	shift
+	realname=$1
+	shift
+
+	if test -n "$soname_spec"; then
+	  eval soname=\"$soname_spec\"
+	else
+	  soname=$realname
+	fi
+	if test -z "$dlname"; then
+	  dlname=$soname
+	fi
+
+	lib=$output_objdir/$realname
+	linknames=
+	for link
+	do
+	  func_append linknames " $link"
+	done
+
+	# Use standard objects if they are pic
+	test -z "$pic_flag" && libobjs=`$ECHO "$libobjs" | $SP2NL | $SED "$lo2o" | $NL2SP`
+	test "X$libobjs" = "X " && libobjs=
+
+	delfiles=
+	if test -n "$export_symbols" && test -n "$include_expsyms"; then
+	  $opt_dry_run || cp "$export_symbols" "$output_objdir/$libname.uexp"
+	  export_symbols=$output_objdir/$libname.uexp
+	  func_append delfiles " $export_symbols"
+	fi
+
+	orig_export_symbols=
+	case $host_os in
+	cygwin* | mingw* | cegcc*)
+	  if test -n "$export_symbols" && test -z "$export_symbols_regex"; then
+	    # exporting using user supplied symfile
+	    func_dll_def_p "$export_symbols" || {
+	      # and it's NOT already a .def file. Must figure out
+	      # which of the given symbols are data symbols and tag
+	      # them as such. So, trigger use of export_symbols_cmds.
+	      # export_symbols gets reassigned inside the "prepare
+	      # the list of exported symbols" if statement, so the
+	      # include_expsyms logic still works.
+	      orig_export_symbols=$export_symbols
+	      export_symbols=
+	      always_export_symbols=yes
+	    }
+	  fi
+	  ;;
+	esac
+
+	# Prepare the list of exported symbols
+	if test -z "$export_symbols"; then
+	  if test yes = "$always_export_symbols" || test -n "$export_symbols_regex"; then
+	    func_verbose "generating symbol list for '$libname.la'"
+	    export_symbols=$output_objdir/$libname.exp
+	    $opt_dry_run || $RM $export_symbols
+	    cmds=$export_symbols_cmds
+	    save_ifs=$IFS; IFS='~'
+	    for cmd1 in $cmds; do
+	      IFS=$save_ifs
+	      # Take the normal branch if the nm_file_list_spec branch
+	      # doesn't work or if tool conversion is not needed.
+	      case $nm_file_list_spec~$to_tool_file_cmd in
+		*~func_convert_file_noop | *~func_convert_file_msys_to_w32 | ~*)
+		  try_normal_branch=yes
+		  eval cmd=\"$cmd1\"
+		  func_len " $cmd"
+		  len=$func_len_result
+		  ;;
+		*)
+		  try_normal_branch=no
+		  ;;
+	      esac
+	      if test yes = "$try_normal_branch" \
+		 && { test "$len" -lt "$max_cmd_len" \
+		      || test "$max_cmd_len" -le -1; }
+	      then
+		func_show_eval "$cmd" 'exit $?'
+		skipped_export=false
+	      elif test -n "$nm_file_list_spec"; then
+		func_basename "$output"
+		output_la=$func_basename_result
+		save_libobjs=$libobjs
+		save_output=$output
+		output=$output_objdir/$output_la.nm
+		func_to_tool_file "$output"
+		libobjs=$nm_file_list_spec$func_to_tool_file_result
+		func_append delfiles " $output"
+		func_verbose "creating $NM input file list: $output"
+		for obj in $save_libobjs; do
+		  func_to_tool_file "$obj"
+		  $ECHO "$func_to_tool_file_result"
+		done > "$output"
+		eval cmd=\"$cmd1\"
+		func_show_eval "$cmd" 'exit $?'
+		output=$save_output
+		libobjs=$save_libobjs
+		skipped_export=false
+	      else
+		# The command line is too long to execute in one step.
+		func_verbose "using reloadable object file for export list..."
+		skipped_export=:
+		# Break out early, otherwise skipped_export may be
+		# set to false by a later but shorter cmd.
+		break
+	      fi
+	    done
+	    IFS=$save_ifs
+	    if test -n "$export_symbols_regex" && test : != "$skipped_export"; then
+	      func_show_eval '$EGREP -e "$export_symbols_regex" "$export_symbols" > "${export_symbols}T"'
+	      func_show_eval '$MV "${export_symbols}T" "$export_symbols"'
+	    fi
+	  fi
+	fi
+
+	if test -n "$export_symbols" && test -n "$include_expsyms"; then
+	  tmp_export_symbols=$export_symbols
+	  test -n "$orig_export_symbols" && tmp_export_symbols=$orig_export_symbols
+	  $opt_dry_run || eval '$ECHO "$include_expsyms" | $SP2NL >> "$tmp_export_symbols"'
+	fi
+
+	if test : != "$skipped_export" && test -n "$orig_export_symbols"; then
+	  # The given exports_symbols file has to be filtered, so filter it.
+	  func_verbose "filter symbol list for '$libname.la' to tag DATA exports"
+	  # FIXME: $output_objdir/$libname.filter potentially contains lots of
+	  # 's' commands, which not all seds can handle. GNU sed should be fine
+	  # though. Also, the filter scales superlinearly with the number of
+	  # global variables. join(1) would be nice here, but unfortunately
+	  # isn't a blessed tool.
+	  $opt_dry_run || $SED -e '/[ ,]DATA/!d;s,\(.*\)\([ \,].*\),s|^\1$|\1\2|,' < $export_symbols > $output_objdir/$libname.filter
+	  func_append delfiles " $export_symbols $output_objdir/$libname.filter"
+	  export_symbols=$output_objdir/$libname.def
+	  $opt_dry_run || $SED -f $output_objdir/$libname.filter < $orig_export_symbols > $export_symbols
+	fi
+
+	tmp_deplibs=
+	for test_deplib in $deplibs; do
+	  case " $convenience " in
+	  *" $test_deplib "*) ;;
+	  *)
+	    func_append tmp_deplibs " $test_deplib"
+	    ;;
+	  esac
+	done
+	deplibs=$tmp_deplibs
+
+	if test -n "$convenience"; then
+	  if test -n "$whole_archive_flag_spec" &&
+	    test yes = "$compiler_needs_object" &&
+	    test -z "$libobjs"; then
+	    # extract the archives, so we have objects to list.
+	    # TODO: could optimize this to just extract one archive.
+	    whole_archive_flag_spec=
+	  fi
+	  if test -n "$whole_archive_flag_spec"; then
+	    save_libobjs=$libobjs
+	    eval libobjs=\"\$libobjs $whole_archive_flag_spec\"
+	    test "X$libobjs" = "X " && libobjs=
+	  else
+	    gentop=$output_objdir/${outputname}x
+	    func_append generated " $gentop"
+
+	    func_extract_archives $gentop $convenience
+	    func_append libobjs " $func_extract_archives_result"
+	    test "X$libobjs" = "X " && libobjs=
+	  fi
+	fi
+
+	if test yes = "$thread_safe" && test -n "$thread_safe_flag_spec"; then
+	  eval flag=\"$thread_safe_flag_spec\"
+	  func_append linker_flags " $flag"
+	fi
+
+	# Make a backup of the uninstalled library when relinking
+	if test relink = "$opt_mode"; then
+	  $opt_dry_run || eval '(cd $output_objdir && $RM ${realname}U && $MV $realname ${realname}U)' || exit $?
+	fi
+
+	# Do each of the archive commands.
+	if test yes = "$module" && test -n "$module_cmds"; then
+	  if test -n "$export_symbols" && test -n "$module_expsym_cmds"; then
+	    eval test_cmds=\"$module_expsym_cmds\"
+	    cmds=$module_expsym_cmds
+	  else
+	    eval test_cmds=\"$module_cmds\"
+	    cmds=$module_cmds
+	  fi
+	else
+	  if test -n "$export_symbols" && test -n "$archive_expsym_cmds"; then
+	    eval test_cmds=\"$archive_expsym_cmds\"
+	    cmds=$archive_expsym_cmds
+	  else
+	    eval test_cmds=\"$archive_cmds\"
+	    cmds=$archive_cmds
+	  fi
+	fi
+
+	if test : != "$skipped_export" &&
+	   func_len " $test_cmds" &&
+	   len=$func_len_result &&
+	   test "$len" -lt "$max_cmd_len" || test "$max_cmd_len" -le -1; then
+	  :
+	else
+	  # The command line is too long to link in one step, link piecewise
+	  # or, if using GNU ld and skipped_export is not :, use a linker
+	  # script.
+
+	  # Save the value of $output and $libobjs because we want to
+	  # use them later.  If we have whole_archive_flag_spec, we
+	  # want to use save_libobjs as it was before
+	  # whole_archive_flag_spec was expanded, because we can't
+	  # assume the linker understands whole_archive_flag_spec.
+	  # This may have to be revisited, in case too many
+	  # convenience libraries get linked in and end up exceeding
+	  # the spec.
+	  if test -z "$convenience" || test -z "$whole_archive_flag_spec"; then
+	    save_libobjs=$libobjs
+	  fi
+	  save_output=$output
+	  func_basename "$output"
+	  output_la=$func_basename_result
+
+	  # Clear the reloadable object creation command queue and
+	  # initialize k to one.
+	  test_cmds=
+	  concat_cmds=
+	  objlist=
+	  last_robj=
+	  k=1
+
+	  if test -n "$save_libobjs" && test : != "$skipped_export" && test yes = "$with_gnu_ld"; then
+	    output=$output_objdir/$output_la.lnkscript
+	    func_verbose "creating GNU ld script: $output"
+	    echo 'INPUT (' > $output
+	    for obj in $save_libobjs
+	    do
+	      func_to_tool_file "$obj"
+	      $ECHO "$func_to_tool_file_result" >> $output
+	    done
+	    echo ')' >> $output
+	    func_append delfiles " $output"
+	    func_to_tool_file "$output"
+	    output=$func_to_tool_file_result
+	  elif test -n "$save_libobjs" && test : != "$skipped_export" && test -n "$file_list_spec"; then
+	    output=$output_objdir/$output_la.lnk
+	    func_verbose "creating linker input file list: $output"
+	    : > $output
+	    set x $save_libobjs
+	    shift
+	    firstobj=
+	    if test yes = "$compiler_needs_object"; then
+	      firstobj="$1 "
+	      shift
+	    fi
+	    for obj
+	    do
+	      func_to_tool_file "$obj"
+	      $ECHO "$func_to_tool_file_result" >> $output
+	    done
+	    func_append delfiles " $output"
+	    func_to_tool_file "$output"
+	    output=$firstobj\"$file_list_spec$func_to_tool_file_result\"
+	  else
+	    if test -n "$save_libobjs"; then
+	      func_verbose "creating reloadable object files..."
+	      output=$output_objdir/$output_la-$k.$objext
+	      eval test_cmds=\"$reload_cmds\"
+	      func_len " $test_cmds"
+	      len0=$func_len_result
+	      len=$len0
+
+	      # Loop over the list of objects to be linked.
+	      for obj in $save_libobjs
+	      do
+		func_len " $obj"
+		func_arith $len + $func_len_result
+		len=$func_arith_result
+		if test -z "$objlist" ||
+		   test "$len" -lt "$max_cmd_len"; then
+		  func_append objlist " $obj"
+		else
+		  # The command $test_cmds is almost too long, add a
+		  # command to the queue.
+		  if test 1 -eq "$k"; then
+		    # The first file doesn't have a previous command to add.
+		    reload_objs=$objlist
+		    eval concat_cmds=\"$reload_cmds\"
+		  else
+		    # All subsequent reloadable object files will link in
+		    # the last one created.
+		    reload_objs="$objlist $last_robj"
+		    eval concat_cmds=\"\$concat_cmds~$reload_cmds~\$RM $last_robj\"
+		  fi
+		  last_robj=$output_objdir/$output_la-$k.$objext
+		  func_arith $k + 1
+		  k=$func_arith_result
+		  output=$output_objdir/$output_la-$k.$objext
+		  objlist=" $obj"
+		  func_len " $last_robj"
+		  func_arith $len0 + $func_len_result
+		  len=$func_arith_result
+		fi
+	      done
+	      # Handle the remaining objects by creating one last
+	      # reloadable object file.  All subsequent reloadable object
+	      # files will link in the last one created.
+	      test -z "$concat_cmds" || concat_cmds=$concat_cmds~
+	      reload_objs="$objlist $last_robj"
+	      eval concat_cmds=\"\$concat_cmds$reload_cmds\"
+	      if test -n "$last_robj"; then
+	        eval concat_cmds=\"\$concat_cmds~\$RM $last_robj\"
+	      fi
+	      func_append delfiles " $output"
+
+	    else
+	      output=
+	    fi
+
+	    ${skipped_export-false} && {
+	      func_verbose "generating symbol list for '$libname.la'"
+	      export_symbols=$output_objdir/$libname.exp
+	      $opt_dry_run || $RM $export_symbols
+	      libobjs=$output
+	      # Append the command to create the export file.
+	      test -z "$concat_cmds" || concat_cmds=$concat_cmds~
+	      eval concat_cmds=\"\$concat_cmds$export_symbols_cmds\"
+	      if test -n "$last_robj"; then
+		eval concat_cmds=\"\$concat_cmds~\$RM $last_robj\"
+	      fi
+	    }
+
+	    test -n "$save_libobjs" &&
+	      func_verbose "creating a temporary reloadable object file: $output"
+
+	    # Loop through the commands generated above and execute them.
+	    save_ifs=$IFS; IFS='~'
+	    for cmd in $concat_cmds; do
+	      IFS=$save_ifs
+	      $opt_quiet || {
+		  func_quote_for_expand "$cmd"
+		  eval "func_echo $func_quote_for_expand_result"
+	      }
+	      $opt_dry_run || eval "$cmd" || {
+		lt_exit=$?
+
+		# Restore the uninstalled library and exit
+		if test relink = "$opt_mode"; then
+		  ( cd "$output_objdir" && \
+		    $RM "${realname}T" && \
+		    $MV "${realname}U" "$realname" )
+		fi
+
+		exit $lt_exit
+	      }
+	    done
+	    IFS=$save_ifs
+
+	    if test -n "$export_symbols_regex" && ${skipped_export-false}; then
+	      func_show_eval '$EGREP -e "$export_symbols_regex" "$export_symbols" > "${export_symbols}T"'
+	      func_show_eval '$MV "${export_symbols}T" "$export_symbols"'
+	    fi
+	  fi
+
+          ${skipped_export-false} && {
+	    if test -n "$export_symbols" && test -n "$include_expsyms"; then
+	      tmp_export_symbols=$export_symbols
+	      test -n "$orig_export_symbols" && tmp_export_symbols=$orig_export_symbols
+	      $opt_dry_run || eval '$ECHO "$include_expsyms" | $SP2NL >> "$tmp_export_symbols"'
+	    fi
+
+	    if test -n "$orig_export_symbols"; then
+	      # The given exports_symbols file has to be filtered, so filter it.
+	      func_verbose "filter symbol list for '$libname.la' to tag DATA exports"
+	      # FIXME: $output_objdir/$libname.filter potentially contains lots of
+	      # 's' commands, which not all seds can handle. GNU sed should be fine
+	      # though. Also, the filter scales superlinearly with the number of
+	      # global variables. join(1) would be nice here, but unfortunately
+	      # isn't a blessed tool.
+	      $opt_dry_run || $SED -e '/[ ,]DATA/!d;s,\(.*\)\([ \,].*\),s|^\1$|\1\2|,' < $export_symbols > $output_objdir/$libname.filter
+	      func_append delfiles " $export_symbols $output_objdir/$libname.filter"
+	      export_symbols=$output_objdir/$libname.def
+	      $opt_dry_run || $SED -f $output_objdir/$libname.filter < $orig_export_symbols > $export_symbols
+	    fi
+	  }
+
+	  libobjs=$output
+	  # Restore the value of output.
+	  output=$save_output
+
+	  if test -n "$convenience" && test -n "$whole_archive_flag_spec"; then
+	    eval libobjs=\"\$libobjs $whole_archive_flag_spec\"
+	    test "X$libobjs" = "X " && libobjs=
+	  fi
+	  # Expand the library linking commands again to reset the
+	  # value of $libobjs for piecewise linking.
+
+	  # Do each of the archive commands.
+	  if test yes = "$module" && test -n "$module_cmds"; then
+	    if test -n "$export_symbols" && test -n "$module_expsym_cmds"; then
+	      cmds=$module_expsym_cmds
+	    else
+	      cmds=$module_cmds
+	    fi
+	  else
+	    if test -n "$export_symbols" && test -n "$archive_expsym_cmds"; then
+	      cmds=$archive_expsym_cmds
+	    else
+	      cmds=$archive_cmds
+	    fi
+	  fi
+	fi
+
+	if test -n "$delfiles"; then
+	  # Append the command to remove temporary files to $cmds.
+	  eval cmds=\"\$cmds~\$RM $delfiles\"
+	fi
+
+	# Add any objects from preloaded convenience libraries
+	if test -n "$dlprefiles"; then
+	  gentop=$output_objdir/${outputname}x
+	  func_append generated " $gentop"
+
+	  func_extract_archives $gentop $dlprefiles
+	  func_append libobjs " $func_extract_archives_result"
+	  test "X$libobjs" = "X " && libobjs=
+	fi
+
+	save_ifs=$IFS; IFS='~'
+	for cmd in $cmds; do
+	  IFS=$sp$nl
+	  eval cmd=\"$cmd\"
+	  IFS=$save_ifs
+	  $opt_quiet || {
+	    func_quote_for_expand "$cmd"
+	    eval "func_echo $func_quote_for_expand_result"
+	  }
+	  $opt_dry_run || eval "$cmd" || {
+	    lt_exit=$?
+
+	    # Restore the uninstalled library and exit
+	    if test relink = "$opt_mode"; then
+	      ( cd "$output_objdir" && \
+	        $RM "${realname}T" && \
+		$MV "${realname}U" "$realname" )
+	    fi
+
+	    exit $lt_exit
+	  }
+	done
+	IFS=$save_ifs
+
+	# Restore the uninstalled library and exit
+	if test relink = "$opt_mode"; then
+	  $opt_dry_run || eval '(cd $output_objdir && $RM ${realname}T && $MV $realname ${realname}T && $MV ${realname}U $realname)' || exit $?
+
+	  if test -n "$convenience"; then
+	    if test -z "$whole_archive_flag_spec"; then
+	      func_show_eval '${RM}r "$gentop"'
+	    fi
+	  fi
+
+	  exit $EXIT_SUCCESS
+	fi
+
+	# Create links to the real library.
+	for linkname in $linknames; do
+	  if test "$realname" != "$linkname"; then
+	    func_show_eval '(cd "$output_objdir" && $RM "$linkname" && $LN_S "$realname" "$linkname")' 'exit $?'
+	  fi
+	done
+
+	# If -module or -export-dynamic was specified, set the dlname.
+	if test yes = "$module" || test yes = "$export_dynamic"; then
+	  # On all known operating systems, these are identical.
+	  dlname=$soname
+	fi
+      fi
+      ;;
+
+    obj)
+      if test -n "$dlfiles$dlprefiles" || test no != "$dlself"; then
+	func_warning "'-dlopen' is ignored for objects"
+      fi
+
+      case " $deplibs" in
+      *\ -l* | *\ -L*)
+	func_warning "'-l' and '-L' are ignored for objects" ;;
+      esac
+
+      test -n "$rpath" && \
+	func_warning "'-rpath' is ignored for objects"
+
+      test -n "$xrpath" && \
+	func_warning "'-R' is ignored for objects"
+
+      test -n "$vinfo" && \
+	func_warning "'-version-info' is ignored for objects"
+
+      test -n "$release" && \
+	func_warning "'-release' is ignored for objects"
+
+      case $output in
+      *.lo)
+	test -n "$objs$old_deplibs" && \
+	  func_fatal_error "cannot build library object '$output' from non-libtool objects"
+
+	libobj=$output
+	func_lo2o "$libobj"
+	obj=$func_lo2o_result
+	;;
+      *)
+	libobj=
+	obj=$output
+	;;
+      esac
+
+      # Delete the old objects.
+      $opt_dry_run || $RM $obj $libobj
+
+      # Objects from convenience libraries.  This assumes
+      # single-version convenience libraries.  Whenever we create
+      # different ones for PIC/non-PIC, this we'll have to duplicate
+      # the extraction.
+      reload_conv_objs=
+      gentop=
+      # if reload_cmds runs $LD directly, get rid of -Wl from
+      # whole_archive_flag_spec and hope we can get by with turning comma
+      # into space.
+      case $reload_cmds in
+        *\$LD[\ \$]*) wl= ;;
+      esac
+      if test -n "$convenience"; then
+	if test -n "$whole_archive_flag_spec"; then
+	  eval tmp_whole_archive_flags=\"$whole_archive_flag_spec\"
+	  test -n "$wl" || tmp_whole_archive_flags=`$ECHO "$tmp_whole_archive_flags" | $SED 's|,| |g'`
+	  reload_conv_objs=$reload_objs\ $tmp_whole_archive_flags
+	else
+	  gentop=$output_objdir/${obj}x
+	  func_append generated " $gentop"
+
+	  func_extract_archives $gentop $convenience
+	  reload_conv_objs="$reload_objs $func_extract_archives_result"
+	fi
+      fi
+
+      # If we're not building shared, we need to use non_pic_objs
+      test yes = "$build_libtool_libs" || libobjs=$non_pic_objects
+
+      # Create the old-style object.
+      reload_objs=$objs$old_deplibs' '`$ECHO "$libobjs" | $SP2NL | $SED "/\.$libext$/d; /\.lib$/d; $lo2o" | $NL2SP`' '$reload_conv_objs
+
+      output=$obj
+      func_execute_cmds "$reload_cmds" 'exit $?'
+
+      # Exit if we aren't doing a library object file.
+      if test -z "$libobj"; then
+	if test -n "$gentop"; then
+	  func_show_eval '${RM}r "$gentop"'
+	fi
+
+	exit $EXIT_SUCCESS
+      fi
+
+      test yes = "$build_libtool_libs" || {
+	if test -n "$gentop"; then
+	  func_show_eval '${RM}r "$gentop"'
+	fi
+
+	# Create an invalid libtool object if no PIC, so that we don't
+	# accidentally link it into a program.
+	# $show "echo timestamp > $libobj"
+	# $opt_dry_run || eval "echo timestamp > $libobj" || exit $?
+	exit $EXIT_SUCCESS
+      }
+
+      if test -n "$pic_flag" || test default != "$pic_mode"; then
+	# Only do commands if we really have different PIC objects.
+	reload_objs="$libobjs $reload_conv_objs"
+	output=$libobj
+	func_execute_cmds "$reload_cmds" 'exit $?'
+      fi
+
+      if test -n "$gentop"; then
+	func_show_eval '${RM}r "$gentop"'
+      fi
+
+      exit $EXIT_SUCCESS
+      ;;
+
+    prog)
+      case $host in
+	*cygwin*) func_stripname '' '.exe' "$output"
+	          output=$func_stripname_result.exe;;
+      esac
+      test -n "$vinfo" && \
+	func_warning "'-version-info' is ignored for programs"
+
+      test -n "$release" && \
+	func_warning "'-release' is ignored for programs"
+
+      $preload \
+	&& test unknown,unknown,unknown = "$dlopen_support,$dlopen_self,$dlopen_self_static" \
+	&& func_warning "'LT_INIT([dlopen])' not used. Assuming no dlopen support."
+
+      case $host in
+      *-*-rhapsody* | *-*-darwin1.[012])
+	# On Rhapsody replace the C library is the System framework
+	compile_deplibs=`$ECHO " $compile_deplibs" | $SED 's/ -lc / System.ltframework /'`
+	finalize_deplibs=`$ECHO " $finalize_deplibs" | $SED 's/ -lc / System.ltframework /'`
+	;;
+      esac
+
+      case $host in
+      *-*-darwin*)
+	# Don't allow lazy linking, it breaks C++ global constructors
+	# But is supposedly fixed on 10.4 or later (yay!).
+	if test CXX = "$tagname"; then
+	  case ${MACOSX_DEPLOYMENT_TARGET-10.0} in
+	    10.[0123])
+	      func_append compile_command " $wl-bind_at_load"
+	      func_append finalize_command " $wl-bind_at_load"
+	    ;;
+	  esac
+	fi
+	# Time to change all our "foo.ltframework" stuff back to "-framework foo"
+	compile_deplibs=`$ECHO " $compile_deplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	finalize_deplibs=`$ECHO " $finalize_deplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	;;
+      esac
+
+
+      # move library search paths that coincide with paths to not yet
+      # installed libraries to the beginning of the library search list
+      new_libs=
+      for path in $notinst_path; do
+	case " $new_libs " in
+	*" -L$path/$objdir "*) ;;
+	*)
+	  case " $compile_deplibs " in
+	  *" -L$path/$objdir "*)
+	    func_append new_libs " -L$path/$objdir" ;;
+	  esac
+	  ;;
+	esac
+      done
+      for deplib in $compile_deplibs; do
+	case $deplib in
+	-L*)
+	  case " $new_libs " in
+	  *" $deplib "*) ;;
+	  *) func_append new_libs " $deplib" ;;
+	  esac
+	  ;;
+	*) func_append new_libs " $deplib" ;;
+	esac
+      done
+      compile_deplibs=$new_libs
+
+
+      func_append compile_command " $compile_deplibs"
+      func_append finalize_command " $finalize_deplibs"
+
+      if test -n "$rpath$xrpath"; then
+	# If the user specified any rpath flags, then add them.
+	for libdir in $rpath $xrpath; do
+	  # This is the magic to use -rpath.
+	  case "$finalize_rpath " in
+	  *" $libdir "*) ;;
+	  *) func_append finalize_rpath " $libdir" ;;
+	  esac
+	done
+      fi
+
+      # Now hardcode the library paths
+      rpath=
+      hardcode_libdirs=
+      for libdir in $compile_rpath $finalize_rpath; do
+	if test -n "$hardcode_libdir_flag_spec"; then
+	  if test -n "$hardcode_libdir_separator"; then
+	    if test -z "$hardcode_libdirs"; then
+	      hardcode_libdirs=$libdir
+	    else
+	      # Just accumulate the unique libdirs.
+	      case $hardcode_libdir_separator$hardcode_libdirs$hardcode_libdir_separator in
+	      *"$hardcode_libdir_separator$libdir$hardcode_libdir_separator"*)
+		;;
+	      *)
+		func_append hardcode_libdirs "$hardcode_libdir_separator$libdir"
+		;;
+	      esac
+	    fi
+	  else
+	    eval flag=\"$hardcode_libdir_flag_spec\"
+	    func_append rpath " $flag"
+	  fi
+	elif test -n "$runpath_var"; then
+	  case "$perm_rpath " in
+	  *" $libdir "*) ;;
+	  *) func_append perm_rpath " $libdir" ;;
+	  esac
+	fi
+	case $host in
+	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
+	  testbindir=`$ECHO "$libdir" | $SED -e 's*/lib$*/bin*'`
+	  case :$dllsearchpath: in
+	  *":$libdir:"*) ;;
+	  ::) dllsearchpath=$libdir;;
+	  *) func_append dllsearchpath ":$libdir";;
+	  esac
+	  case :$dllsearchpath: in
+	  *":$testbindir:"*) ;;
+	  ::) dllsearchpath=$testbindir;;
+	  *) func_append dllsearchpath ":$testbindir";;
+	  esac
+	  ;;
+	esac
+      done
+      # Substitute the hardcoded libdirs into the rpath.
+      if test -n "$hardcode_libdir_separator" &&
+	 test -n "$hardcode_libdirs"; then
+	libdir=$hardcode_libdirs
+	eval rpath=\" $hardcode_libdir_flag_spec\"
+      fi
+      compile_rpath=$rpath
+
+      rpath=
+      hardcode_libdirs=
+      for libdir in $finalize_rpath; do
+	if test -n "$hardcode_libdir_flag_spec"; then
+	  if test -n "$hardcode_libdir_separator"; then
+	    if test -z "$hardcode_libdirs"; then
+	      hardcode_libdirs=$libdir
+	    else
+	      # Just accumulate the unique libdirs.
+	      case $hardcode_libdir_separator$hardcode_libdirs$hardcode_libdir_separator in
+	      *"$hardcode_libdir_separator$libdir$hardcode_libdir_separator"*)
+		;;
+	      *)
+		func_append hardcode_libdirs "$hardcode_libdir_separator$libdir"
+		;;
+	      esac
+	    fi
+	  else
+	    eval flag=\"$hardcode_libdir_flag_spec\"
+	    func_append rpath " $flag"
+	  fi
+	elif test -n "$runpath_var"; then
+	  case "$finalize_perm_rpath " in
+	  *" $libdir "*) ;;
+	  *) func_append finalize_perm_rpath " $libdir" ;;
+	  esac
+	fi
+      done
+      # Substitute the hardcoded libdirs into the rpath.
+      if test -n "$hardcode_libdir_separator" &&
+	 test -n "$hardcode_libdirs"; then
+	libdir=$hardcode_libdirs
+	eval rpath=\" $hardcode_libdir_flag_spec\"
+      fi
+      finalize_rpath=$rpath
+
+      if test -n "$libobjs" && test yes = "$build_old_libs"; then
+	# Transform all the library objects into standard objects.
+	compile_command=`$ECHO "$compile_command" | $SP2NL | $SED "$lo2o" | $NL2SP`
+	finalize_command=`$ECHO "$finalize_command" | $SP2NL | $SED "$lo2o" | $NL2SP`
+      fi
+
+      func_generate_dlsyms "$outputname" "@PROGRAM@" false
+
+      # template prelinking step
+      if test -n "$prelink_cmds"; then
+	func_execute_cmds "$prelink_cmds" 'exit $?'
+      fi
+
+      wrappers_required=:
+      case $host in
+      *cegcc* | *mingw32ce*)
+        # Disable wrappers for cegcc and mingw32ce hosts, we are cross compiling anyway.
+        wrappers_required=false
+        ;;
+      *cygwin* | *mingw* )
+        test yes = "$build_libtool_libs" || wrappers_required=false
+        ;;
+      *)
+        if test no = "$need_relink" || test yes != "$build_libtool_libs"; then
+          wrappers_required=false
+        fi
+        ;;
+      esac
+      $wrappers_required || {
+	# Replace the output file specification.
+	compile_command=`$ECHO "$compile_command" | $SED 's%@OUTPUT@%'"$output"'%g'`
+	link_command=$compile_command$compile_rpath
+
+	# We have no uninstalled library dependencies, so finalize right now.
+	exit_status=0
+	func_show_eval "$link_command" 'exit_status=$?'
+
+	if test -n "$postlink_cmds"; then
+	  func_to_tool_file "$output"
+	  postlink_cmds=`func_echo_all "$postlink_cmds" | $SED -e 's%@OUTPUT@%'"$output"'%g' -e 's%@TOOL_OUTPUT@%'"$func_to_tool_file_result"'%g'`
+	  func_execute_cmds "$postlink_cmds" 'exit $?'
+	fi
+
+	# Delete the generated files.
+	if test -f "$output_objdir/${outputname}S.$objext"; then
+	  func_show_eval '$RM "$output_objdir/${outputname}S.$objext"'
+	fi
+
+	exit $exit_status
+      }
+
+      if test -n "$compile_shlibpath$finalize_shlibpath"; then
+	compile_command="$shlibpath_var=\"$compile_shlibpath$finalize_shlibpath\$$shlibpath_var\" $compile_command"
+      fi
+      if test -n "$finalize_shlibpath"; then
+	finalize_command="$shlibpath_var=\"$finalize_shlibpath\$$shlibpath_var\" $finalize_command"
+      fi
+
+      compile_var=
+      finalize_var=
+      if test -n "$runpath_var"; then
+	if test -n "$perm_rpath"; then
+	  # We should set the runpath_var.
+	  rpath=
+	  for dir in $perm_rpath; do
+	    func_append rpath "$dir:"
+	  done
+	  compile_var="$runpath_var=\"$rpath\$$runpath_var\" "
+	fi
+	if test -n "$finalize_perm_rpath"; then
+	  # We should set the runpath_var.
+	  rpath=
+	  for dir in $finalize_perm_rpath; do
+	    func_append rpath "$dir:"
+	  done
+	  finalize_var="$runpath_var=\"$rpath\$$runpath_var\" "
+	fi
+      fi
+
+      if test yes = "$no_install"; then
+	# We don't need to create a wrapper script.
+	link_command=$compile_var$compile_command$compile_rpath
+	# Replace the output file specification.
+	link_command=`$ECHO "$link_command" | $SED 's%@OUTPUT@%'"$output"'%g'`
+	# Delete the old output file.
+	$opt_dry_run || $RM $output
+	# Link the executable and exit
+	func_show_eval "$link_command" 'exit $?'
+
+	if test -n "$postlink_cmds"; then
+	  func_to_tool_file "$output"
+	  postlink_cmds=`func_echo_all "$postlink_cmds" | $SED -e 's%@OUTPUT@%'"$output"'%g' -e 's%@TOOL_OUTPUT@%'"$func_to_tool_file_result"'%g'`
+	  func_execute_cmds "$postlink_cmds" 'exit $?'
+	fi
+
+	exit $EXIT_SUCCESS
+      fi
+
+      case $hardcode_action,$fast_install in
+        relink,*)
+	  # Fast installation is not supported
+	  link_command=$compile_var$compile_command$compile_rpath
+	  relink_command=$finalize_var$finalize_command$finalize_rpath
+
+	  func_warning "this platform does not like uninstalled shared libraries"
+	  func_warning "'$output' will be relinked during installation"
+	  ;;
+        *,yes)
+	  link_command=$finalize_var$compile_command$finalize_rpath
+	  relink_command=`$ECHO "$compile_var$compile_command$compile_rpath" | $SED 's%@OUTPUT@%\$progdir/\$file%g'`
+          ;;
+	*,no)
+	  link_command=$compile_var$compile_command$compile_rpath
+	  relink_command=$finalize_var$finalize_command$finalize_rpath
+          ;;
+	*,needless)
+	  link_command=$finalize_var$compile_command$finalize_rpath
+	  relink_command=
+          ;;
+      esac
+
+      # Replace the output file specification.
+      link_command=`$ECHO "$link_command" | $SED 's%@OUTPUT@%'"$output_objdir/$outputname"'%g'`
+
+      # Delete the old output files.
+      $opt_dry_run || $RM $output $output_objdir/$outputname $output_objdir/lt-$outputname
+
+      func_show_eval "$link_command" 'exit $?'
+
+      if test -n "$postlink_cmds"; then
+	func_to_tool_file "$output_objdir/$outputname"
+	postlink_cmds=`func_echo_all "$postlink_cmds" | $SED -e 's%@OUTPUT@%'"$output_objdir/$outputname"'%g' -e 's%@TOOL_OUTPUT@%'"$func_to_tool_file_result"'%g'`
+	func_execute_cmds "$postlink_cmds" 'exit $?'
+      fi
+
+      # Now create the wrapper script.
+      func_verbose "creating $output"
+
+      # Quote the relink command for shipping.
+      if test -n "$relink_command"; then
+	# Preserve any variables that may affect compiler behavior
+	for var in $variables_saved_for_relink; do
+	  if eval test -z \"\${$var+set}\"; then
+	    relink_command="{ test -z \"\${$var+set}\" || $lt_unset $var || { $var=; export $var; }; }; $relink_command"
+	  elif eval var_value=\$$var; test -z "$var_value"; then
+	    relink_command="$var=; export $var; $relink_command"
+	  else
+	    func_quote_for_eval "$var_value"
+	    relink_command="$var=$func_quote_for_eval_result; export $var; $relink_command"
+	  fi
+	done
+	relink_command="(cd `pwd`; $relink_command)"
+	relink_command=`$ECHO "$relink_command" | $SED "$sed_quote_subst"`
+      fi
+
+      # Only actually do things if not in dry run mode.
+      $opt_dry_run || {
+	# win32 will think the script is a binary if it has
+	# a .exe suffix, so we strip it off here.
+	case $output in
+	  *.exe) func_stripname '' '.exe' "$output"
+	         output=$func_stripname_result ;;
+	esac
+	# test for cygwin because mv fails w/o .exe extensions
+	case $host in
+	  *cygwin*)
+	    exeext=.exe
+	    func_stripname '' '.exe' "$outputname"
+	    outputname=$func_stripname_result ;;
+	  *) exeext= ;;
+	esac
+	case $host in
+	  *cygwin* | *mingw* )
+	    func_dirname_and_basename "$output" "" "."
+	    output_name=$func_basename_result
+	    output_path=$func_dirname_result
+	    cwrappersource=$output_path/$objdir/lt-$output_name.c
+	    cwrapper=$output_path/$output_name.exe
+	    $RM $cwrappersource $cwrapper
+	    trap "$RM $cwrappersource $cwrapper; exit $EXIT_FAILURE" 1 2 15
+
+	    func_emit_cwrapperexe_src > $cwrappersource
+
+	    # The wrapper executable is built using the $host compiler,
+	    # because it contains $host paths and files. If cross-
+	    # compiling, it, like the target executable, must be
+	    # executed on the $host or under an emulation environment.
+	    $opt_dry_run || {
+	      $LTCC $LTCFLAGS -o $cwrapper $cwrappersource
+	      $STRIP $cwrapper
+	    }
+
+	    # Now, create the wrapper script for func_source use:
+	    func_ltwrapper_scriptname $cwrapper
+	    $RM $func_ltwrapper_scriptname_result
+	    trap "$RM $func_ltwrapper_scriptname_result; exit $EXIT_FAILURE" 1 2 15
+	    $opt_dry_run || {
+	      # note: this script will not be executed, so do not chmod.
+	      if test "x$build" = "x$host"; then
+		$cwrapper --lt-dump-script > $func_ltwrapper_scriptname_result
+	      else
+		func_emit_wrapper no > $func_ltwrapper_scriptname_result
+	      fi
+	    }
+	  ;;
+	  * )
+	    $RM $output
+	    trap "$RM $output; exit $EXIT_FAILURE" 1 2 15
+
+	    func_emit_wrapper no > $output
+	    chmod +x $output
+	  ;;
+	esac
+      }
+      exit $EXIT_SUCCESS
+      ;;
+    esac
+
+    # See if we need to build an old-fashioned archive.
+    for oldlib in $oldlibs; do
+
+      case $build_libtool_libs in
+        convenience)
+	  oldobjs="$libobjs_save $symfileobj"
+	  addlibs=$convenience
+	  build_libtool_libs=no
+	  ;;
+	module)
+	  oldobjs=$libobjs_save
+	  addlibs=$old_convenience
+	  build_libtool_libs=no
+          ;;
+	*)
+	  oldobjs="$old_deplibs $non_pic_objects"
+	  $preload && test -f "$symfileobj" \
+	    && func_append oldobjs " $symfileobj"
+	  addlibs=$old_convenience
+	  ;;
+      esac
+
+      if test -n "$addlibs"; then
+	gentop=$output_objdir/${outputname}x
+	func_append generated " $gentop"
+
+	func_extract_archives $gentop $addlibs
+	func_append oldobjs " $func_extract_archives_result"
+      fi
+
+      # Do each command in the archive commands.
+      if test -n "$old_archive_from_new_cmds" && test yes = "$build_libtool_libs"; then
+	cmds=$old_archive_from_new_cmds
+      else
+
+	# Add any objects from preloaded convenience libraries
+	if test -n "$dlprefiles"; then
+	  gentop=$output_objdir/${outputname}x
+	  func_append generated " $gentop"
+
+	  func_extract_archives $gentop $dlprefiles
+	  func_append oldobjs " $func_extract_archives_result"
+	fi
+
+	# POSIX demands no paths to be encoded in archives.  We have
+	# to avoid creating archives with duplicate basenames if we
+	# might have to extract them afterwards, e.g., when creating a
+	# static archive out of a convenience library, or when linking
+	# the entirety of a libtool archive into another (currently
+	# not supported by libtool).
+	if (for obj in $oldobjs
+	    do
+	      func_basename "$obj"
+	      $ECHO "$func_basename_result"
+	    done | sort | sort -uc >/dev/null 2>&1); then
+	  :
+	else
+	  echo "copying selected object files to avoid basename conflicts..."
+	  gentop=$output_objdir/${outputname}x
+	  func_append generated " $gentop"
+	  func_mkdir_p "$gentop"
+	  save_oldobjs=$oldobjs
+	  oldobjs=
+	  counter=1
+	  for obj in $save_oldobjs
+	  do
+	    func_basename "$obj"
+	    objbase=$func_basename_result
+	    case " $oldobjs " in
+	    " ") oldobjs=$obj ;;
+	    *[\ /]"$objbase "*)
+	      while :; do
+		# Make sure we don't pick an alternate name that also
+		# overlaps.
+		newobj=lt$counter-$objbase
+		func_arith $counter + 1
+		counter=$func_arith_result
+		case " $oldobjs " in
+		*[\ /]"$newobj "*) ;;
+		*) if test ! -f "$gentop/$newobj"; then break; fi ;;
+		esac
+	      done
+	      func_show_eval "ln $obj $gentop/$newobj || cp $obj $gentop/$newobj"
+	      func_append oldobjs " $gentop/$newobj"
+	      ;;
+	    *) func_append oldobjs " $obj" ;;
+	    esac
+	  done
+	fi
+	func_to_tool_file "$oldlib" func_convert_file_msys_to_w32
+	tool_oldlib=$func_to_tool_file_result
+	eval cmds=\"$old_archive_cmds\"
+
+	func_len " $cmds"
+	len=$func_len_result
+	if test "$len" -lt "$max_cmd_len" || test "$max_cmd_len" -le -1; then
+	  cmds=$old_archive_cmds
+	elif test -n "$archiver_list_spec"; then
+	  func_verbose "using command file archive linking..."
+	  for obj in $oldobjs
+	  do
+	    func_to_tool_file "$obj"
+	    $ECHO "$func_to_tool_file_result"
+	  done > $output_objdir/$libname.libcmd
+	  func_to_tool_file "$output_objdir/$libname.libcmd"
+	  oldobjs=" $archiver_list_spec$func_to_tool_file_result"
+	  cmds=$old_archive_cmds
+	else
+	  # the command line is too long to link in one step, link in parts
+	  func_verbose "using piecewise archive linking..."
+	  save_RANLIB=$RANLIB
+	  RANLIB=:
+	  objlist=
+	  concat_cmds=
+	  save_oldobjs=$oldobjs
+	  oldobjs=
+	  # Is there a better way of finding the last object in the list?
+	  for obj in $save_oldobjs
+	  do
+	    last_oldobj=$obj
+	  done
+	  eval test_cmds=\"$old_archive_cmds\"
+	  func_len " $test_cmds"
+	  len0=$func_len_result
+	  len=$len0
+	  for obj in $save_oldobjs
+	  do
+	    func_len " $obj"
+	    func_arith $len + $func_len_result
+	    len=$func_arith_result
+	    func_append objlist " $obj"
+	    if test "$len" -lt "$max_cmd_len"; then
+	      :
+	    else
+	      # the above command should be used before it gets too long
+	      oldobjs=$objlist
+	      if test "$obj" = "$last_oldobj"; then
+		RANLIB=$save_RANLIB
+	      fi
+	      test -z "$concat_cmds" || concat_cmds=$concat_cmds~
+	      eval concat_cmds=\"\$concat_cmds$old_archive_cmds\"
+	      objlist=
+	      len=$len0
+	    fi
+	  done
+	  RANLIB=$save_RANLIB
+	  oldobjs=$objlist
+	  if test -z "$oldobjs"; then
+	    eval cmds=\"\$concat_cmds\"
+	  else
+	    eval cmds=\"\$concat_cmds~\$old_archive_cmds\"
+	  fi
+	fi
+      fi
+      func_execute_cmds "$cmds" 'exit $?'
+    done
+
+    test -n "$generated" && \
+      func_show_eval "${RM}r$generated"
+
+    # Now create the libtool archive.
+    case $output in
+    *.la)
+      old_library=
+      test yes = "$build_old_libs" && old_library=$libname.$libext
+      func_verbose "creating $output"
+
+      # Preserve any variables that may affect compiler behavior
+      for var in $variables_saved_for_relink; do
+	if eval test -z \"\${$var+set}\"; then
+	  relink_command="{ test -z \"\${$var+set}\" || $lt_unset $var || { $var=; export $var; }; }; $relink_command"
+	elif eval var_value=\$$var; test -z "$var_value"; then
+	  relink_command="$var=; export $var; $relink_command"
+	else
+	  func_quote_for_eval "$var_value"
+	  relink_command="$var=$func_quote_for_eval_result; export $var; $relink_command"
+	fi
+      done
+      # Quote the link command for shipping.
+      relink_command="(cd `pwd`; $SHELL \"$progpath\" $preserve_args --mode=relink $libtool_args @inst_prefix_dir@)"
+      relink_command=`$ECHO "$relink_command" | $SED "$sed_quote_subst"`
+      if test yes = "$hardcode_automatic"; then
+	relink_command=
+      fi
+
+      # Only create the output if not a dry run.
+      $opt_dry_run || {
+	for installed in no yes; do
+	  if test yes = "$installed"; then
+	    if test -z "$install_libdir"; then
+	      break
+	    fi
+	    output=$output_objdir/${outputname}i
+	    # Replace all uninstalled libtool libraries with the installed ones
+	    newdependency_libs=
+	    for deplib in $dependency_libs; do
+	      case $deplib in
+	      *.la)
+		func_basename "$deplib"
+		name=$func_basename_result
+		func_resolve_sysroot "$deplib"
+		eval libdir=`$SED -n -e 's/^libdir=\(.*\)$/\1/p' $func_resolve_sysroot_result`
+		test -z "$libdir" && \
+		  func_fatal_error "'$deplib' is not a valid libtool archive"
+		func_append newdependency_libs " ${lt_sysroot:+=}$libdir/$name"
+		;;
+	      -L*)
+		func_stripname -L '' "$deplib"
+		func_replace_sysroot "$func_stripname_result"
+		func_append newdependency_libs " -L$func_replace_sysroot_result"
+		;;
+	      -R*)
+		func_stripname -R '' "$deplib"
+		func_replace_sysroot "$func_stripname_result"
+		func_append newdependency_libs " -R$func_replace_sysroot_result"
+		;;
+	      *) func_append newdependency_libs " $deplib" ;;
+	      esac
+	    done
+	    dependency_libs=$newdependency_libs
+	    newdlfiles=
+
+	    for lib in $dlfiles; do
+	      case $lib in
+	      *.la)
+	        func_basename "$lib"
+		name=$func_basename_result
+		eval libdir=`$SED -n -e 's/^libdir=\(.*\)$/\1/p' $lib`
+		test -z "$libdir" && \
+		  func_fatal_error "'$lib' is not a valid libtool archive"
+		func_append newdlfiles " ${lt_sysroot:+=}$libdir/$name"
+		;;
+	      *) func_append newdlfiles " $lib" ;;
+	      esac
+	    done
+	    dlfiles=$newdlfiles
+	    newdlprefiles=
+	    for lib in $dlprefiles; do
+	      case $lib in
+	      *.la)
+		# Only pass preopened files to the pseudo-archive (for
+		# eventual linking with the app. that links it) if we
+		# didn't already link the preopened objects directly into
+		# the library:
+		func_basename "$lib"
+		name=$func_basename_result
+		eval libdir=`$SED -n -e 's/^libdir=\(.*\)$/\1/p' $lib`
+		test -z "$libdir" && \
+		  func_fatal_error "'$lib' is not a valid libtool archive"
+		func_append newdlprefiles " ${lt_sysroot:+=}$libdir/$name"
+		;;
+	      esac
+	    done
+	    dlprefiles=$newdlprefiles
+	  else
+	    newdlfiles=
+	    for lib in $dlfiles; do
+	      case $lib in
+		[\\/]* | [A-Za-z]:[\\/]*) abs=$lib ;;
+		*) abs=`pwd`"/$lib" ;;
+	      esac
+	      func_append newdlfiles " $abs"
+	    done
+	    dlfiles=$newdlfiles
+	    newdlprefiles=
+	    for lib in $dlprefiles; do
+	      case $lib in
+		[\\/]* | [A-Za-z]:[\\/]*) abs=$lib ;;
+		*) abs=`pwd`"/$lib" ;;
+	      esac
+	      func_append newdlprefiles " $abs"
+	    done
+	    dlprefiles=$newdlprefiles
+	  fi
+	  $RM $output
+	  # place dlname in correct position for cygwin
+	  # In fact, it would be nice if we could use this code for all target
+	  # systems that can't hard-code library paths into their executables
+	  # and that have no shared library path variable independent of PATH,
+	  # but it turns out we can't easily determine that from inspecting
+	  # libtool variables, so we have to hard-code the OSs to which it
+	  # applies here; at the moment, that means platforms that use the PE
+	  # object format with DLL files.  See the long comment at the top of
+	  # tests/bindir.at for full details.
+	  tdlname=$dlname
+	  case $host,$output,$installed,$module,$dlname in
+	    *cygwin*,*lai,yes,no,*.dll | *mingw*,*lai,yes,no,*.dll | *cegcc*,*lai,yes,no,*.dll)
+	      # If a -bindir argument was supplied, place the dll there.
+	      if test -n "$bindir"; then
+		func_relative_path "$install_libdir" "$bindir"
+		tdlname=$func_relative_path_result/$dlname
+	      else
+		# Otherwise fall back on heuristic.
+		tdlname=../bin/$dlname
+	      fi
+	      ;;
+	  esac
+	  $ECHO > $output "\
+# $outputname - a libtool library file
+# Generated by $PROGRAM (GNU $PACKAGE) $VERSION
+#
+# Please DO NOT delete this file!
+# It is necessary for linking the library.
+
+# The name that we can dlopen(3).
+dlname='$tdlname'
+
+# Names of this library.
+library_names='$library_names'
+
+# The name of the static archive.
+old_library='$old_library'
+
+# Linker flags that cannot go in dependency_libs.
+inherited_linker_flags='$new_inherited_linker_flags'
+
+# Libraries that this one depends upon.
+dependency_libs='$dependency_libs'
+
+# Names of additional weak libraries provided by this library
+weak_library_names='$weak_libs'
+
+# Version information for $libname.
+current=$current
+age=$age
+revision=$revision
+
+# Is this an already installed library?
+installed=$installed
+
+# Should we warn about portability when linking against -modules?
+shouldnotlink=$module
+
+# Files to dlopen/dlpreopen
+dlopen='$dlfiles'
+dlpreopen='$dlprefiles'
+
+# Directory that this library needs to be installed in:
+libdir='$install_libdir'"
+	  if test no,yes = "$installed,$need_relink"; then
+	    $ECHO >> $output "\
+relink_command=\"$relink_command\""
+	  fi
+	done
+      }
+
+      # Do a symbolic link so that the libtool archive can be found in
+      # LD_LIBRARY_PATH before the program is installed.
+      func_show_eval '( cd "$output_objdir" && $RM "$outputname" && $LN_S "../$outputname" "$outputname" )' 'exit $?'
+      ;;
+    esac
+    exit $EXIT_SUCCESS
+}
+
+if test link = "$opt_mode" || test relink = "$opt_mode"; then
+  func_mode_link ${1+"$@"}
+fi
+
+
+# func_mode_uninstall arg...
+func_mode_uninstall ()
+{
+    $debug_cmd
+
+    RM=$nonopt
+    files=
+    rmforce=false
+    exit_status=0
+
+    # This variable tells wrapper scripts just to set variables rather
+    # than running their programs.
+    libtool_install_magic=$magic
+
+    for arg
+    do
+      case $arg in
+      -f) func_append RM " $arg"; rmforce=: ;;
+      -*) func_append RM " $arg" ;;
+      *) func_append files " $arg" ;;
+      esac
+    done
+
+    test -z "$RM" && \
+      func_fatal_help "you must specify an RM program"
+
+    rmdirs=
+
+    for file in $files; do
+      func_dirname "$file" "" "."
+      dir=$func_dirname_result
+      if test . = "$dir"; then
+	odir=$objdir
+      else
+	odir=$dir/$objdir
+      fi
+      func_basename "$file"
+      name=$func_basename_result
+      test uninstall = "$opt_mode" && odir=$dir
+
+      # Remember odir for removal later, being careful to avoid duplicates
+      if test clean = "$opt_mode"; then
+	case " $rmdirs " in
+	  *" $odir "*) ;;
+	  *) func_append rmdirs " $odir" ;;
+	esac
+      fi
+
+      # Don't error if the file doesn't exist and rm -f was used.
+      if { test -L "$file"; } >/dev/null 2>&1 ||
+	 { test -h "$file"; } >/dev/null 2>&1 ||
+	 test -f "$file"; then
+	:
+      elif test -d "$file"; then
+	exit_status=1
+	continue
+      elif $rmforce; then
+	continue
+      fi
+
+      rmfiles=$file
+
+      case $name in
+      *.la)
+	# Possibly a libtool archive, so verify it.
+	if func_lalib_p "$file"; then
+	  func_source $dir/$name
+
+	  # Delete the libtool libraries and symlinks.
+	  for n in $library_names; do
+	    func_append rmfiles " $odir/$n"
+	  done
+	  test -n "$old_library" && func_append rmfiles " $odir/$old_library"
+
+	  case $opt_mode in
+	  clean)
+	    case " $library_names " in
+	    *" $dlname "*) ;;
+	    *) test -n "$dlname" && func_append rmfiles " $odir/$dlname" ;;
+	    esac
+	    test -n "$libdir" && func_append rmfiles " $odir/$name $odir/${name}i"
+	    ;;
+	  uninstall)
+	    if test -n "$library_names"; then
+	      # Do each command in the postuninstall commands.
+	      func_execute_cmds "$postuninstall_cmds" '$rmforce || exit_status=1'
+	    fi
+
+	    if test -n "$old_library"; then
+	      # Do each command in the old_postuninstall commands.
+	      func_execute_cmds "$old_postuninstall_cmds" '$rmforce || exit_status=1'
+	    fi
+	    # FIXME: should reinstall the best remaining shared library.
+	    ;;
+	  esac
+	fi
+	;;
+
+      *.lo)
+	# Possibly a libtool object, so verify it.
+	if func_lalib_p "$file"; then
+
+	  # Read the .lo file
+	  func_source $dir/$name
+
+	  # Add PIC object to the list of files to remove.
+	  if test -n "$pic_object" && test none != "$pic_object"; then
+	    func_append rmfiles " $dir/$pic_object"
+	  fi
+
+	  # Add non-PIC object to the list of files to remove.
+	  if test -n "$non_pic_object" && test none != "$non_pic_object"; then
+	    func_append rmfiles " $dir/$non_pic_object"
+	  fi
+	fi
+	;;
+
+      *)
+	if test clean = "$opt_mode"; then
+	  noexename=$name
+	  case $file in
+	  *.exe)
+	    func_stripname '' '.exe' "$file"
+	    file=$func_stripname_result
+	    func_stripname '' '.exe' "$name"
+	    noexename=$func_stripname_result
+	    # $file with .exe has already been added to rmfiles,
+	    # add $file without .exe
+	    func_append rmfiles " $file"
+	    ;;
+	  esac
+	  # Do a test to see if this is a libtool program.
+	  if func_ltwrapper_p "$file"; then
+	    if func_ltwrapper_executable_p "$file"; then
+	      func_ltwrapper_scriptname "$file"
+	      relink_command=
+	      func_source $func_ltwrapper_scriptname_result
+	      func_append rmfiles " $func_ltwrapper_scriptname_result"
+	    else
+	      relink_command=
+	      func_source $dir/$noexename
+	    fi
+
+	    # note $name still contains .exe if it was in $file originally
+	    # as does the version of $file that was added into $rmfiles
+	    func_append rmfiles " $odir/$name $odir/${name}S.$objext"
+	    if test yes = "$fast_install" && test -n "$relink_command"; then
+	      func_append rmfiles " $odir/lt-$name"
+	    fi
+	    if test "X$noexename" != "X$name"; then
+	      func_append rmfiles " $odir/lt-$noexename.c"
+	    fi
+	  fi
+	fi
+	;;
+      esac
+      func_show_eval "$RM $rmfiles" 'exit_status=1'
+    done
+
+    # Try to remove the $objdir's in the directories where we deleted files
+    for dir in $rmdirs; do
+      if test -d "$dir"; then
+	func_show_eval "rmdir $dir >/dev/null 2>&1"
+      fi
+    done
+
+    exit $exit_status
+}
+
+if test uninstall = "$opt_mode" || test clean = "$opt_mode"; then
+  func_mode_uninstall ${1+"$@"}
+fi
+
+test -z "$opt_mode" && {
+  help=$generic_help
+  func_fatal_help "you must specify a MODE"
+}
+
+test -z "$exec_cmd" && \
+  func_fatal_help "invalid operation mode '$opt_mode'"
+
+if test -n "$exec_cmd"; then
+  eval exec "$exec_cmd"
+  exit $EXIT_FAILURE
+fi
+
+exit $exit_status
+
+
+# The TAGs below are defined such that we never get into a situation
+# where we disable both kinds of libraries.  Given conflicting
+# choices, we go for a static library, that is the most portable,
+# since we can't tell whether shared libraries were disabled because
+# the user asked for that or because the platform doesn't support
+# them.  This is particularly important on AIX, because we don't
+# support having both static and shared libraries enabled at the same
+# time on that platform, so we default to a shared-only configuration.
+# If a disable-shared tag is given, we'll fallback to a static-only
+# configuration.  But we'll never go from static-only to shared-only.
+
+# ### BEGIN LIBTOOL TAG CONFIG: disable-shared
+build_libtool_libs=no
+build_old_libs=yes
+# ### END LIBTOOL TAG CONFIG: disable-shared
+
+# ### BEGIN LIBTOOL TAG CONFIG: disable-static
+build_old_libs=`case $build_libtool_libs in yes) echo no;; *) echo yes;; esac`
+# ### END LIBTOOL TAG CONFIG: disable-static
+
+# Local Variables:
+# mode:shell-script
+# sh-indentation:2
+# End:
diff --git a/extern/libpng/mips/filter_msa_intrinsics.c b/extern/libpng/mips/filter_msa_intrinsics.c
new file mode 100644
index 0000000000..a579179421
--- /dev/null
+++ b/extern/libpng/mips/filter_msa_intrinsics.c
@@ -0,0 +1,808 @@
+
+/* filter_msa_intrinsics.c - MSA optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2016 Glenn Randers-Pehrson
+ * Written by Mandar Sahastrabuddhe, August 2016.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* This code requires -mfpu=msa on the command line: */
+#if PNG_MIPS_MSA_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+#include <msa.h>
+
+/* libpng row pointers are not necessarily aligned to any particular boundary,
+ * however this code will only work with appropriate alignment. mips/mips_init.c
+ * checks for this (and will not compile unless it is done). This code uses
+ * variants of png_aligncast to avoid compiler warnings.
+ */
+#define png_ptr(type,pointer) png_aligncast(type *,pointer)
+#define png_ptrc(type,pointer) png_aligncastconst(const type *,pointer)
+
+/* The following relies on a variable 'temp_pointer' being declared with type
+ * 'type'.  This is written this way just to hide the GCC strict aliasing
+ * warning; note that the code is safe because there never is an alias between
+ * the input and output pointers.
+ */
+#define png_ldr(type,pointer)\
+   (temp_pointer = png_ptr(type,pointer), *temp_pointer)
+
+#if PNG_MIPS_MSA_OPT > 0
+
+#ifdef CLANG_BUILD
+   #define MSA_SRLI_B(a, b)   __msa_srli_b((v16i8) a, b)
+
+   #define LW(psrc)                              \
+   ( {                                           \
+       uint8_t *psrc_lw_m = (uint8_t *) (psrc);  \
+       uint32_t val_m;                           \
+                                                 \
+       asm volatile (                            \
+           "lw  %[val_m],  %[psrc_lw_m]  \n\t"   \
+                                                 \
+           : [val_m] "=r" (val_m)                \
+           : [psrc_lw_m] "m" (*psrc_lw_m)        \
+       );                                        \
+                                                 \
+       val_m;                                    \
+   } )
+
+   #define SH(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sh_m = (uint8_t *) (pdst);  \
+       uint16_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "sh  %[val_m],  %[pdst_sh_m]  \n\t"   \
+                                                 \
+           : [pdst_sh_m] "=m" (*pdst_sh_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #define SW(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sw_m = (uint8_t *) (pdst);  \
+       uint32_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "sw  %[val_m],  %[pdst_sw_m]  \n\t"   \
+                                                 \
+           : [pdst_sw_m] "=m" (*pdst_sw_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+       #if (__mips == 64)
+        #define SD(val, pdst)                         \
+        {                                             \
+            uint8_t *pdst_sd_m = (uint8_t *) (pdst);  \
+            uint64_t val_m = (val);                   \
+                                                      \
+            asm volatile (                            \
+                "sd  %[val_m],  %[pdst_sd_m]  \n\t"   \
+                                                      \
+                : [pdst_sd_m] "=m" (*pdst_sd_m)       \
+                : [val_m] "r" (val_m)                 \
+            );                                        \
+        }
+    #else
+        #define SD(val, pdst)                                          \
+        {                                                              \
+            uint8_t *pdst_sd_m = (uint8_t *) (pdst);                   \
+            uint32_t val0_m, val1_m;                                   \
+                                                                       \
+            val0_m = (uint32_t) ((val) & 0x00000000FFFFFFFF);          \
+            val1_m = (uint32_t) (((val) >> 32) & 0x00000000FFFFFFFF);  \
+                                                                       \
+            SW(val0_m, pdst_sd_m);                                     \
+            SW(val1_m, pdst_sd_m + 4);                                 \
+        }
+    #endif
+#else
+   #define MSA_SRLI_B(a, b)   (a >> b)
+
+#if (__mips_isa_rev >= 6)
+   #define LW(psrc)                              \
+   ( {                                           \
+       uint8_t *psrc_lw_m = (uint8_t *) (psrc);  \
+       uint32_t val_m;                           \
+                                                 \
+       asm volatile (                            \
+           "lw  %[val_m],  %[psrc_lw_m]  \n\t"   \
+                                                 \
+           : [val_m] "=r" (val_m)                \
+           : [psrc_lw_m] "m" (*psrc_lw_m)        \
+       );                                        \
+                                                 \
+       val_m;                                    \
+   } )
+
+   #define SH(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sh_m = (uint8_t *) (pdst);  \
+       uint16_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "sh  %[val_m],  %[pdst_sh_m]  \n\t"   \
+                                                 \
+           : [pdst_sh_m] "=m" (*pdst_sh_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #define SW(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sw_m = (uint8_t *) (pdst);  \
+       uint32_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "sw  %[val_m],  %[pdst_sw_m]  \n\t"   \
+                                                 \
+           : [pdst_sw_m] "=m" (*pdst_sw_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #if (__mips == 64)
+        #define SD(val, pdst)                         \
+        {                                             \
+            uint8_t *pdst_sd_m = (uint8_t *) (pdst);  \
+            uint64_t val_m = (val);                   \
+                                                      \
+            asm volatile (                            \
+                "sd  %[val_m],  %[pdst_sd_m]  \n\t"   \
+                                                      \
+                : [pdst_sd_m] "=m" (*pdst_sd_m)       \
+                : [val_m] "r" (val_m)                 \
+            );                                        \
+        }
+    #else
+        #define SD(val, pdst)                                          \
+        {                                                              \
+            uint8_t *pdst_sd_m = (uint8_t *) (pdst);                   \
+            uint32_t val0_m, val1_m;                                   \
+                                                                       \
+            val0_m = (uint32_t) ((val) & 0x00000000FFFFFFFF);          \
+            val1_m = (uint32_t) (((val) >> 32) & 0x00000000FFFFFFFF);  \
+                                                                       \
+            SW(val0_m, pdst_sd_m);                                     \
+            SW(val1_m, pdst_sd_m + 4);                                 \
+        }
+    #endif
+#else  // !(__mips_isa_rev >= 6)
+   #define LW(psrc)                              \
+   ( {                                           \
+       uint8_t *psrc_lw_m = (uint8_t *) (psrc);  \
+       uint32_t val_m;                           \
+                                                 \
+       asm volatile (                            \
+           "ulw  %[val_m],  %[psrc_lw_m]  \n\t"  \
+                                                 \
+           : [val_m] "=r" (val_m)                \
+           : [psrc_lw_m] "m" (*psrc_lw_m)        \
+       );                                        \
+                                                 \
+       val_m;                                    \
+   } )
+
+   #define SH(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sh_m = (uint8_t *) (pdst);  \
+       uint16_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "ush  %[val_m],  %[pdst_sh_m]  \n\t"  \
+                                                 \
+           : [pdst_sh_m] "=m" (*pdst_sh_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #define SW(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sw_m = (uint8_t *) (pdst);  \
+       uint32_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "usw  %[val_m],  %[pdst_sw_m]  \n\t"  \
+                                                 \
+           : [pdst_sw_m] "=m" (*pdst_sw_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #define SD(val, pdst)                                          \
+    {                                                              \
+        uint8_t *pdst_sd_m = (uint8_t *) (pdst);                   \
+        uint32_t val0_m, val1_m;                                   \
+                                                                   \
+        val0_m = (uint32_t) ((val) & 0x00000000FFFFFFFF);          \
+        val1_m = (uint32_t) (((val) >> 32) & 0x00000000FFFFFFFF);  \
+                                                                   \
+        SW(val0_m, pdst_sd_m);                                     \
+        SW(val1_m, pdst_sd_m + 4);                                 \
+    }
+
+    #define SW_ZERO(pdst)                      \
+    {                                          \
+        uint8_t *pdst_m = (uint8_t *) (pdst);  \
+                                               \
+        asm volatile (                         \
+            "usw  $0,  %[pdst_m]  \n\t"        \
+                                               \
+            : [pdst_m] "=m" (*pdst_m)          \
+            :                                  \
+        );                                     \
+    }
+#endif  // (__mips_isa_rev >= 6)
+#endif
+
+#define LD_B(RTYPE, psrc) *((RTYPE *) (psrc))
+#define LD_UB(...) LD_B(v16u8, __VA_ARGS__)
+#define LD_B2(RTYPE, psrc, stride, out0, out1)  \
+{                                               \
+    out0 = LD_B(RTYPE, (psrc));                 \
+    out1 = LD_B(RTYPE, (psrc) + stride);        \
+}
+#define LD_UB2(...) LD_B2(v16u8, __VA_ARGS__)
+#define LD_B4(RTYPE, psrc, stride, out0, out1, out2, out3)   \
+{                                                            \
+    LD_B2(RTYPE, (psrc), stride, out0, out1);                \
+    LD_B2(RTYPE, (psrc) + 2 * stride , stride, out2, out3);  \
+}
+#define LD_UB4(...) LD_B4(v16u8, __VA_ARGS__)
+
+#define ST_B(RTYPE, in, pdst) *((RTYPE *) (pdst)) = (in)
+#define ST_UB(...) ST_B(v16u8, __VA_ARGS__)
+#define ST_B2(RTYPE, in0, in1, pdst, stride)  \
+{                                             \
+    ST_B(RTYPE, in0, (pdst));                 \
+    ST_B(RTYPE, in1, (pdst) + stride);        \
+}
+#define ST_UB2(...) ST_B2(v16u8, __VA_ARGS__)
+#define ST_B4(RTYPE, in0, in1, in2, in3, pdst, stride)    \
+{                                                         \
+    ST_B2(RTYPE, in0, in1, (pdst), stride);               \
+    ST_B2(RTYPE, in2, in3, (pdst) + 2 * stride, stride);  \
+}
+#define ST_UB4(...) ST_B4(v16u8, __VA_ARGS__)
+
+#define ADD2(in0, in1, in2, in3, out0, out1)  \
+{                                             \
+    out0 = in0 + in1;                         \
+    out1 = in2 + in3;                         \
+}
+#define ADD3(in0, in1, in2, in3, in4, in5,  \
+             out0, out1, out2)              \
+{                                           \
+    ADD2(in0, in1, in2, in3, out0, out1);   \
+    out2 = in4 + in5;                       \
+}
+#define ADD4(in0, in1, in2, in3, in4, in5, in6, in7,  \
+             out0, out1, out2, out3)                  \
+{                                                     \
+    ADD2(in0, in1, in2, in3, out0, out1);             \
+    ADD2(in4, in5, in6, in7, out2, out3);             \
+}
+
+#define ILVR_B2(RTYPE, in0, in1, in2, in3, out0, out1)      \
+{                                                           \
+    out0 = (RTYPE) __msa_ilvr_b((v16i8) in0, (v16i8) in1);  \
+    out1 = (RTYPE) __msa_ilvr_b((v16i8) in2, (v16i8) in3);  \
+}
+#define ILVR_B2_SH(...) ILVR_B2(v8i16, __VA_ARGS__)
+
+#define HSUB_UB2(RTYPE, in0, in1, out0, out1)                 \
+{                                                             \
+    out0 = (RTYPE) __msa_hsub_u_h((v16u8) in0, (v16u8) in0);  \
+    out1 = (RTYPE) __msa_hsub_u_h((v16u8) in1, (v16u8) in1);  \
+}
+#define HSUB_UB2_SH(...) HSUB_UB2(v8i16, __VA_ARGS__)
+
+#define SLDI_B2_0(RTYPE, in0, in1, out0, out1, slide_val)                 \
+{                                                                         \
+    v16i8 zero_m = { 0 };                                                 \
+    out0 = (RTYPE) __msa_sldi_b((v16i8) zero_m, (v16i8) in0, slide_val);  \
+    out1 = (RTYPE) __msa_sldi_b((v16i8) zero_m, (v16i8) in1, slide_val);  \
+}
+#define SLDI_B2_0_UB(...) SLDI_B2_0(v16u8, __VA_ARGS__)
+
+#define SLDI_B3_0(RTYPE, in0, in1, in2, out0, out1, out2,  slide_val)     \
+{                                                                         \
+    v16i8 zero_m = { 0 };                                                 \
+    SLDI_B2_0(RTYPE, in0, in1, out0, out1, slide_val);                    \
+    out2 = (RTYPE) __msa_sldi_b((v16i8) zero_m, (v16i8) in2, slide_val);  \
+}
+#define SLDI_B3_0_UB(...) SLDI_B3_0(v16u8, __VA_ARGS__)
+
+#define ILVEV_W2(RTYPE, in0, in1, in2, in3, out0, out1)      \
+{                                                            \
+    out0 = (RTYPE) __msa_ilvev_w((v4i32) in1, (v4i32) in0);  \
+    out1 = (RTYPE) __msa_ilvev_w((v4i32) in3, (v4i32) in2);  \
+}
+#define ILVEV_W2_UB(...) ILVEV_W2(v16u8, __VA_ARGS__)
+
+#define ADD_ABS_H3(RTYPE, in0, in1, in2, out0, out1, out2)  \
+{                                                           \
+    RTYPE zero = {0};                                       \
+                                                            \
+    out0 = __msa_add_a_h((v8i16) zero, in0);                \
+    out1 = __msa_add_a_h((v8i16) zero, in1);                \
+    out2 = __msa_add_a_h((v8i16) zero, in2);                \
+}
+#define ADD_ABS_H3_SH(...) ADD_ABS_H3(v8i16, __VA_ARGS__)
+
+#define VSHF_B2(RTYPE, in0, in1, in2, in3, mask0, mask1, out0, out1)       \
+{                                                                          \
+    out0 = (RTYPE) __msa_vshf_b((v16i8) mask0, (v16i8) in1, (v16i8) in0);  \
+    out1 = (RTYPE) __msa_vshf_b((v16i8) mask1, (v16i8) in3, (v16i8) in2);  \
+}
+#define VSHF_B2_UB(...) VSHF_B2(v16u8, __VA_ARGS__)
+
+#define CMP_AND_SELECT(inp0, inp1, inp2, inp3, inp4, inp5, out0)              \
+{                                                                             \
+   v8i16 _sel_h0, _sel_h1;                                                    \
+   v16u8 _sel_b0, _sel_b1;                                                    \
+   _sel_h0 = (v8i16) __msa_clt_u_h((v8u16) inp1, (v8u16) inp0);               \
+   _sel_b0 = (v16u8) __msa_pckev_b((v16i8) _sel_h0, (v16i8) _sel_h0);         \
+   inp0 = (v8i16) __msa_bmnz_v((v16u8) inp0, (v16u8) inp1, (v16u8) _sel_h0);  \
+   inp4 = (v16u8) __msa_bmnz_v(inp3, inp4, _sel_b0);                          \
+   _sel_h1 = (v8i16) __msa_clt_u_h((v8u16) inp2, (v8u16) inp0);               \
+   _sel_b1 = (v16u8) __msa_pckev_b((v16i8) _sel_h1, (v16i8) _sel_h1);         \
+   inp4 = (v16u8) __msa_bmnz_v(inp4, inp5, _sel_b1);                          \
+   out0 += inp4;                                                              \
+}
+
+void png_read_filter_row_up_msa(png_row_infop row_info, png_bytep row,
+                                png_const_bytep prev_row)
+{
+   size_t i, cnt, cnt16, cnt32;
+   size_t istop = row_info->rowbytes;
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7;
+
+   for (i = 0; i < (istop >> 6); i++)
+   {
+      LD_UB4(rp, 16, src0, src1, src2, src3);
+      LD_UB4(pp, 16, src4, src5, src6, src7);
+      pp += 64;
+
+	  ADD4(src0, src4, src1, src5, src2, src6, src3, src7,
+	       src0, src1, src2, src3);
+
+      ST_UB4(src0, src1, src2, src3, rp, 16);
+      rp += 64;
+   }
+
+   if (istop & 0x3F)
+   {
+      cnt32 = istop & 0x20;
+      cnt16 = istop & 0x10;
+      cnt = istop & 0xF;
+
+      if(cnt32)
+      {
+         if (cnt16 && cnt)
+         {
+            LD_UB4(rp, 16, src0, src1, src2, src3);
+            LD_UB4(pp, 16, src4, src5, src6, src7);
+
+            ADD4(src0, src4, src1, src5, src2, src6, src3, src7,
+	             src0, src1, src2, src3);
+
+            ST_UB4(src0, src1, src2, src3, rp, 16);
+            rp += 64;
+         }
+         else if (cnt16 || cnt)
+         {
+            LD_UB2(rp, 16, src0, src1);
+            LD_UB2(pp, 16, src4, src5);
+            pp += 32;
+            src2 = LD_UB(rp + 32);
+            src6 = LD_UB(pp);
+
+            ADD3(src0, src4, src1, src5, src2, src6, src0, src1, src2);
+
+            ST_UB2(src0, src1, rp, 16);
+            rp += 32;
+            ST_UB(src2, rp);
+            rp += 16;
+         }
+         else
+         {
+            LD_UB2(rp, 16, src0, src1);
+            LD_UB2(pp, 16, src4, src5);
+
+			ADD2(src0, src4, src1, src5, src0, src1);
+
+            ST_UB2(src0, src1, rp, 16);
+            rp += 32;
+         }
+      }
+      else if (cnt16 && cnt)
+      {
+         LD_UB2(rp, 16, src0, src1);
+         LD_UB2(pp, 16, src4, src5);
+
+         ADD2(src0, src4, src1, src5, src0, src1);
+
+         ST_UB2(src0, src1, rp, 16);
+         rp += 32;
+      }
+      else if (cnt16 || cnt)
+      {
+         src0 = LD_UB(rp);
+         src4 = LD_UB(pp);
+         pp += 16;
+
+         src0 += src4;
+
+         ST_UB(src0, rp);
+         rp += 16;
+      }
+   }
+}
+
+void png_read_filter_row_sub4_msa(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   size_t count;
+   size_t istop = row_info->rowbytes;
+   png_bytep src = row;
+   png_bytep nxt = row + 4;
+   int32_t inp0;
+   v16u8 src0, src1, src2, src3, src4;
+   v16u8 dst0, dst1;
+   v16u8 zero = { 0 };
+
+   istop -= 4;
+
+   inp0 = LW(src);
+   src += 4;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+
+   for (count = 0; count < istop; count += 16)
+   {
+      src1 = LD_UB(src);
+      src += 16;
+
+      src2 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 4);
+      src3 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 8);
+      src4 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 12);
+      src1 += src0;
+      src2 += src1;
+      src3 += src2;
+      src4 += src3;
+      src0 = src4;
+      ILVEV_W2_UB(src1, src2, src3, src4, dst0, dst1);
+      dst0 = (v16u8) __msa_pckev_d((v2i64) dst1, (v2i64) dst0);
+
+      ST_UB(dst0, nxt);
+      nxt += 16;
+   }
+}
+
+void png_read_filter_row_sub3_msa(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   size_t count;
+   size_t istop = row_info->rowbytes;
+   png_bytep src = row;
+   png_bytep nxt = row + 3;
+   int64_t out0;
+   int32_t inp0, out1;
+   v16u8 src0, src1, src2, src3, src4, dst0, dst1;
+   v16u8 zero = { 0 };
+   v16i8 mask0 = { 0, 1, 2, 16, 17, 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+   v16i8 mask1 = { 0, 1, 2, 3, 4, 5, 16, 17, 18, 19, 20, 21, 0, 0, 0, 0 };
+
+   istop -= 3;
+
+   inp0 = LW(src);
+   src += 3;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+
+   for (count = 0; count < istop; count += 12)
+   {
+      src1 = LD_UB(src);
+      src += 12;
+
+      src2 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 3);
+      src3 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 6);
+      src4 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 9);
+      src1 += src0;
+      src2 += src1;
+      src3 += src2;
+      src4 += src3;
+      src0 = src4;
+      VSHF_B2_UB(src1, src2, src3, src4, mask0, mask0, dst0, dst1);
+      dst0 = (v16u8) __msa_vshf_b(mask1, (v16i8) dst1, (v16i8) dst0);
+      out0 = __msa_copy_s_d((v2i64) dst0, 0);
+      out1 = __msa_copy_s_w((v4i32) dst0, 2);
+
+      SD(out0, nxt);
+      nxt += 8;
+      SW(out1, nxt);
+      nxt += 4;
+   }
+}
+
+void png_read_filter_row_avg4_msa(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   size_t i;
+   png_bytep src = row;
+   png_bytep nxt = row;
+   png_const_bytep pp = prev_row;
+   size_t istop = row_info->rowbytes - 4;
+   int32_t inp0, inp1, out0;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7, src8, src9, dst0, dst1;
+   v16u8 zero = { 0 };
+
+   inp0 = LW(pp);
+   pp += 4;
+   inp1 = LW(src);
+   src += 4;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+   src1 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp1);
+   src0 = (v16u8) MSA_SRLI_B(src0, 1);
+   src1 += src0;
+   out0 = __msa_copy_s_w((v4i32) src1, 0);
+   SW(out0, nxt);
+   nxt += 4;
+
+   for (i = 0; i < istop; i += 16)
+   {
+      src2 = LD_UB(pp);
+      pp += 16;
+      src6 = LD_UB(src);
+      src += 16;
+
+      SLDI_B2_0_UB(src2, src6, src3, src7, 4);
+      SLDI_B2_0_UB(src2, src6, src4, src8, 8);
+      SLDI_B2_0_UB(src2, src6, src5, src9, 12);
+      src2 = __msa_ave_u_b(src2, src1);
+      src6 += src2;
+      src3 = __msa_ave_u_b(src3, src6);
+      src7 += src3;
+      src4 = __msa_ave_u_b(src4, src7);
+      src8 += src4;
+      src5 = __msa_ave_u_b(src5, src8);
+      src9 += src5;
+      src1 = src9;
+      ILVEV_W2_UB(src6, src7, src8, src9, dst0, dst1);
+      dst0 = (v16u8) __msa_pckev_d((v2i64) dst1, (v2i64) dst0);
+
+      ST_UB(dst0, nxt);
+      nxt += 16;
+   }
+}
+
+void png_read_filter_row_avg3_msa(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   size_t i;
+   png_bytep src = row;
+   png_bytep nxt = row;
+   png_const_bytep pp = prev_row;
+   size_t istop = row_info->rowbytes - 3;
+   int64_t out0;
+   int32_t inp0, inp1, out1;
+   int16_t out2;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7, src8, src9, dst0, dst1;
+   v16u8 zero = { 0 };
+   v16i8 mask0 = { 0, 1, 2, 16, 17, 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+   v16i8 mask1 = { 0, 1, 2, 3, 4, 5, 16, 17, 18, 19, 20, 21, 0, 0, 0, 0 };
+
+   inp0 = LW(pp);
+   pp += 3;
+   inp1 = LW(src);
+   src += 3;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+   src1 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp1);
+   src0 = (v16u8) MSA_SRLI_B(src0, 1);
+   src1 += src0;
+   out2 = __msa_copy_s_h((v8i16) src1, 0);
+   SH(out2, nxt);
+   nxt += 2;
+   nxt[0] = src1[2];
+   nxt++;
+
+   for (i = 0; i < istop; i += 12)
+   {
+      src2 = LD_UB(pp);
+      pp += 12;
+      src6 = LD_UB(src);
+      src += 12;
+
+      SLDI_B2_0_UB(src2, src6, src3, src7, 3);
+      SLDI_B2_0_UB(src2, src6, src4, src8, 6);
+      SLDI_B2_0_UB(src2, src6, src5, src9, 9);
+      src2 = __msa_ave_u_b(src2, src1);
+      src6 += src2;
+      src3 = __msa_ave_u_b(src3, src6);
+      src7 += src3;
+      src4 = __msa_ave_u_b(src4, src7);
+      src8 += src4;
+      src5 = __msa_ave_u_b(src5, src8);
+      src9 += src5;
+      src1 = src9;
+      VSHF_B2_UB(src6, src7, src8, src9, mask0, mask0, dst0, dst1);
+      dst0 = (v16u8) __msa_vshf_b(mask1, (v16i8) dst1, (v16i8) dst0);
+      out0 = __msa_copy_s_d((v2i64) dst0, 0);
+      out1 = __msa_copy_s_w((v4i32) dst0, 2);
+
+      SD(out0, nxt);
+      nxt += 8;
+      SW(out1, nxt);
+      nxt += 4;
+   }
+}
+
+void png_read_filter_row_paeth4_msa(png_row_infop row_info,
+                                    png_bytep row,
+                                    png_const_bytep prev_row)
+{
+   int32_t count, rp_end;
+   png_bytep nxt;
+   png_const_bytep prev_nxt;
+   int32_t inp0, inp1, res0;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7, src8, src9;
+   v16u8 src10, src11, src12, src13, dst0, dst1;
+   v8i16 vec0, vec1, vec2;
+   v16u8 zero = { 0 };
+
+   nxt = row;
+   prev_nxt = prev_row;
+
+   inp0 = LW(nxt);
+   inp1 = LW(prev_nxt);
+   prev_nxt += 4;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+   src1 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp1);
+
+   src1 += src0;
+   res0 = __msa_copy_s_w((v4i32) src1, 0);
+
+   SW(res0, nxt);
+   nxt += 4;
+
+   /* Remainder */
+   rp_end = row_info->rowbytes - 4;
+
+   for (count = 0; count < rp_end; count += 16)
+   {
+      src2 = LD_UB(prev_nxt);
+      prev_nxt += 16;
+      src6 = LD_UB(prev_row);
+      prev_row += 16;
+      src10 = LD_UB(nxt);
+
+      SLDI_B3_0_UB(src2, src6, src10, src3, src7, src11, 4);
+      SLDI_B3_0_UB(src2, src6, src10, src4, src8, src12, 8);
+      SLDI_B3_0_UB(src2, src6, src10, src5, src9, src13, 12);
+      ILVR_B2_SH(src2, src6, src1, src6, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src1, src2, src6, src10);
+      ILVR_B2_SH(src3, src7, src10, src7, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src10, src3, src7, src11);
+      ILVR_B2_SH(src4, src8, src11, src8, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src11, src4, src8, src12);
+      ILVR_B2_SH(src5, src9, src12, src9, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src12, src5, src9, src13);
+      src1 = src13;
+      ILVEV_W2_UB(src10, src11, src12, src1, dst0, dst1);
+      dst0 = (v16u8) __msa_pckev_d((v2i64) dst1, (v2i64) dst0);
+
+      ST_UB(dst0, nxt);
+      nxt += 16;
+   }
+}
+
+void png_read_filter_row_paeth3_msa(png_row_infop row_info,
+                                    png_bytep row,
+                                    png_const_bytep prev_row)
+{
+   int32_t count, rp_end;
+   png_bytep nxt;
+   png_const_bytep prev_nxt;
+   int64_t out0;
+   int32_t inp0, inp1, out1;
+   int16_t out2;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7, src8, src9, dst0, dst1;
+   v16u8 src10, src11, src12, src13;
+   v8i16 vec0, vec1, vec2;
+   v16u8 zero = { 0 };
+   v16i8 mask0 = { 0, 1, 2, 16, 17, 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+   v16i8 mask1 = { 0, 1, 2, 3, 4, 5, 16, 17, 18, 19, 20, 21, 0, 0, 0, 0 };
+
+   nxt = row;
+   prev_nxt = prev_row;
+
+   inp0 = LW(nxt);
+   inp1 = LW(prev_nxt);
+   prev_nxt += 3;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+   src1 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp1);
+
+   src1 += src0;
+   out2 = __msa_copy_s_h((v8i16) src1, 0);
+
+   SH(out2, nxt);
+   nxt += 2;
+   nxt[0] = src1[2];
+   nxt++;
+
+   /* Remainder */
+   rp_end = row_info->rowbytes - 3;
+
+   for (count = 0; count < rp_end; count += 12)
+   {
+      src2 = LD_UB(prev_nxt);
+      prev_nxt += 12;
+      src6 = LD_UB(prev_row);
+      prev_row += 12;
+      src10 = LD_UB(nxt);
+
+      SLDI_B3_0_UB(src2, src6, src10, src3, src7, src11, 3);
+      SLDI_B3_0_UB(src2, src6, src10, src4, src8, src12, 6);
+      SLDI_B3_0_UB(src2, src6, src10, src5, src9, src13, 9);
+      ILVR_B2_SH(src2, src6, src1, src6, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src1, src2, src6, src10);
+      ILVR_B2_SH(src3, src7, src10, src7, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src10, src3, src7, src11);
+      ILVR_B2_SH(src4, src8, src11, src8, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src11, src4, src8, src12);
+      ILVR_B2_SH(src5, src9, src12, src9, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src12, src5, src9, src13);
+      src1 = src13;
+      VSHF_B2_UB(src10, src11, src12, src13, mask0, mask0, dst0, dst1);
+      dst0 = (v16u8) __msa_vshf_b(mask1, (v16i8) dst1, (v16i8) dst0);
+      out0 = __msa_copy_s_d((v2i64) dst0, 0);
+      out1 = __msa_copy_s_w((v4i32) dst0, 2);
+
+      SD(out0, nxt);
+      nxt += 8;
+      SW(out1, nxt);
+      nxt += 4;
+   }
+}
+
+#endif /* PNG_MIPS_MSA_OPT > 0 */
+#endif /* PNG_MIPS_MSA_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */
diff --git a/extern/libpng/mips/mips_init.c b/extern/libpng/mips/mips_init.c
new file mode 100644
index 0000000000..8dd283deef
--- /dev/null
+++ b/extern/libpng/mips/mips_init.c
@@ -0,0 +1,130 @@
+
+/* mips_init.c - MSA optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2016 Glenn Randers-Pehrson
+ * Written by Mandar Sahastrabuddhe, 2016.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
+ * called.
+ */
+#define _POSIX_SOURCE 1
+
+#include <stdio.h>
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_MIPS_MSA_OPT > 0
+#ifdef PNG_MIPS_MSA_CHECK_SUPPORTED /* Do run-time checks */
+/* WARNING: it is strongly recommended that you do not build libpng with
+ * run-time checks for CPU features if at all possible.  In the case of the MIPS
+ * MSA instructions there is no processor-specific way of detecting the
+ * presence of the required support, therefore run-time detection is extremely
+ * OS specific.
+ *
+ * You may set the macro PNG_MIPS_MSA_FILE to the file name of file containing
+ * a fragment of C source code which defines the png_have_msa function.  There
+ * are a number of implementations in contrib/mips-msa, but the only one that
+ * has partial support is contrib/mips-msa/linux.c - a generic Linux
+ * implementation which reads /proc/cpufino.
+ */
+#ifndef PNG_MIPS_MSA_FILE
+#  ifdef __linux__
+#     define PNG_MIPS_MSA_FILE "contrib/mips-msa/linux.c"
+#  endif
+#endif
+
+#ifdef PNG_MIPS_MSA_FILE
+
+#include <signal.h> /* for sig_atomic_t */
+static int png_have_msa(png_structp png_ptr);
+#include PNG_MIPS_MSA_FILE
+
+#else  /* PNG_MIPS_MSA_FILE */
+#  error "PNG_MIPS_MSA_FILE undefined: no support for run-time MIPS MSA checks"
+#endif /* PNG_MIPS_MSA_FILE */
+#endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
+
+#ifndef PNG_ALIGNED_MEMORY_SUPPORTED
+#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#endif
+
+void
+png_init_filter_functions_msa(png_structp pp, unsigned int bpp)
+{
+   /* The switch statement is compiled in for MIPS_MSA_API, the call to
+    * png_have_msa is compiled in for MIPS_MSA_CHECK. If both are defined
+    * the check is only performed if the API has not set the MSA option on
+    * or off explicitly. In this case the check controls what happens.
+    */
+
+#ifdef PNG_MIPS_MSA_API_SUPPORTED
+   switch ((pp->options >> PNG_MIPS_MSA) & 3)
+   {
+      case PNG_OPTION_UNSET:
+         /* Allow the run-time check to execute if it has been enabled -
+          * thus both API and CHECK can be turned on.  If it isn't supported
+          * this case will fall through to the 'default' below, which just
+          * returns.
+          */
+#endif /* PNG_MIPS_MSA_API_SUPPORTED */
+#ifdef PNG_MIPS_MSA_CHECK_SUPPORTED
+         {
+            static volatile sig_atomic_t no_msa = -1; /* not checked */
+
+            if (no_msa < 0)
+               no_msa = !png_have_msa(pp);
+
+            if (no_msa)
+               return;
+         }
+#ifdef PNG_MIPS_MSA_API_SUPPORTED
+         break;
+#endif
+#endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
+
+#ifdef PNG_MIPS_MSA_API_SUPPORTED
+      default: /* OFF or INVALID */
+         return;
+
+      case PNG_OPTION_ON:
+         /* Option turned on */
+         break;
+   }
+#endif
+
+   /* IMPORTANT: any new external functions used here must be declared using
+    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
+    * 'prefix' option to configure works:
+    *
+    *    ./configure --with-libpng-prefix=foobar_
+    *
+    * Verify you have got this right by running the above command, doing a build
+    * and examining pngprefix.h; it must contain a #define for every external
+    * function you add.  (Notice that this happens automatically for the
+    * initialization function.)
+    */
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_msa;
+
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_msa;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_msa;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_msa;
+   }
+
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_msa;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_msa;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_msa;
+   }
+}
+#endif /* PNG_MIPS_MSA_OPT > 0 */
+#endif /* READ */
diff --git a/extern/libpng/missing b/extern/libpng/missing
new file mode 100755
index 0000000000..625aeb1189
--- /dev/null
+++ b/extern/libpng/missing
@@ -0,0 +1,215 @@
+#! /bin/sh
+# Common wrapper for a few potentially missing GNU programs.
+
+scriptversion=2018-03-07.03; # UTC
+
+# Copyright (C) 1996-2018 Free Software Foundation, Inc.
+# Originally written by Fran,cois Pinard <pinard@iro.umontreal.ca>, 1996.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+if test $# -eq 0; then
+  echo 1>&2 "Try '$0 --help' for more information"
+  exit 1
+fi
+
+case $1 in
+
+  --is-lightweight)
+    # Used by our autoconf macros to check whether the available missing
+    # script is modern enough.
+    exit 0
+    ;;
+
+  --run)
+    # Back-compat with the calling convention used by older automake.
+    shift
+    ;;
+
+  -h|--h|--he|--hel|--help)
+    echo "\
+$0 [OPTION]... PROGRAM [ARGUMENT]...
+
+Run 'PROGRAM [ARGUMENT]...', returning a proper advice when this fails due
+to PROGRAM being missing or too old.
+
+Options:
+  -h, --help      display this help and exit
+  -v, --version   output version information and exit
+
+Supported PROGRAM values:
+  aclocal   autoconf  autoheader   autom4te  automake  makeinfo
+  bison     yacc      flex         lex       help2man
+
+Version suffixes to PROGRAM as well as the prefixes 'gnu-', 'gnu', and
+'g' are ignored when checking the name.
+
+Send bug reports to <bug-automake@gnu.org>."
+    exit $?
+    ;;
+
+  -v|--v|--ve|--ver|--vers|--versi|--versio|--version)
+    echo "missing $scriptversion (GNU Automake)"
+    exit $?
+    ;;
+
+  -*)
+    echo 1>&2 "$0: unknown '$1' option"
+    echo 1>&2 "Try '$0 --help' for more information"
+    exit 1
+    ;;
+
+esac
+
+# Run the given program, remember its exit status.
+"$@"; st=$?
+
+# If it succeeded, we are done.
+test $st -eq 0 && exit 0
+
+# Also exit now if we it failed (or wasn't found), and '--version' was
+# passed; such an option is passed most likely to detect whether the
+# program is present and works.
+case $2 in --version|--help) exit $st;; esac
+
+# Exit code 63 means version mismatch.  This often happens when the user
+# tries to use an ancient version of a tool on a file that requires a
+# minimum version.
+if test $st -eq 63; then
+  msg="probably too old"
+elif test $st -eq 127; then
+  # Program was missing.
+  msg="missing on your system"
+else
+  # Program was found and executed, but failed.  Give up.
+  exit $st
+fi
+
+perl_URL=https://www.perl.org/
+flex_URL=https://github.com/westes/flex
+gnu_software_URL=https://www.gnu.org/software
+
+program_details ()
+{
+  case $1 in
+    aclocal|automake)
+      echo "The '$1' program is part of the GNU Automake package:"
+      echo "<$gnu_software_URL/automake>"
+      echo "It also requires GNU Autoconf, GNU m4 and Perl in order to run:"
+      echo "<$gnu_software_URL/autoconf>"
+      echo "<$gnu_software_URL/m4/>"
+      echo "<$perl_URL>"
+      ;;
+    autoconf|autom4te|autoheader)
+      echo "The '$1' program is part of the GNU Autoconf package:"
+      echo "<$gnu_software_URL/autoconf/>"
+      echo "It also requires GNU m4 and Perl in order to run:"
+      echo "<$gnu_software_URL/m4/>"
+      echo "<$perl_URL>"
+      ;;
+  esac
+}
+
+give_advice ()
+{
+  # Normalize program name to check for.
+  normalized_program=`echo "$1" | sed '
+    s/^gnu-//; t
+    s/^gnu//; t
+    s/^g//; t'`
+
+  printf '%s\n' "'$1' is $msg."
+
+  configure_deps="'configure.ac' or m4 files included by 'configure.ac'"
+  case $normalized_program in
+    autoconf*)
+      echo "You should only need it if you modified 'configure.ac',"
+      echo "or m4 files included by it."
+      program_details 'autoconf'
+      ;;
+    autoheader*)
+      echo "You should only need it if you modified 'acconfig.h' or"
+      echo "$configure_deps."
+      program_details 'autoheader'
+      ;;
+    automake*)
+      echo "You should only need it if you modified 'Makefile.am' or"
+      echo "$configure_deps."
+      program_details 'automake'
+      ;;
+    aclocal*)
+      echo "You should only need it if you modified 'acinclude.m4' or"
+      echo "$configure_deps."
+      program_details 'aclocal'
+      ;;
+   autom4te*)
+      echo "You might have modified some maintainer files that require"
+      echo "the 'autom4te' program to be rebuilt."
+      program_details 'autom4te'
+      ;;
+    bison*|yacc*)
+      echo "You should only need it if you modified a '.y' file."
+      echo "You may want to install the GNU Bison package:"
+      echo "<$gnu_software_URL/bison/>"
+      ;;
+    lex*|flex*)
+      echo "You should only need it if you modified a '.l' file."
+      echo "You may want to install the Fast Lexical Analyzer package:"
+      echo "<$flex_URL>"
+      ;;
+    help2man*)
+      echo "You should only need it if you modified a dependency" \
+           "of a man page."
+      echo "You may want to install the GNU Help2man package:"
+      echo "<$gnu_software_URL/help2man/>"
+    ;;
+    makeinfo*)
+      echo "You should only need it if you modified a '.texi' file, or"
+      echo "any other file indirectly affecting the aspect of the manual."
+      echo "You might want to install the Texinfo package:"
+      echo "<$gnu_software_URL/texinfo/>"
+      echo "The spurious makeinfo call might also be the consequence of"
+      echo "using a buggy 'make' (AIX, DU, IRIX), in which case you might"
+      echo "want to install GNU make:"
+      echo "<$gnu_software_URL/make/>"
+      ;;
+    *)
+      echo "You might have modified some files without having the proper"
+      echo "tools for further handling them.  Check the 'README' file, it"
+      echo "often tells you about the needed prerequisites for installing"
+      echo "this package.  You may also peek at any GNU archive site, in"
+      echo "case some other package contains this missing '$1' program."
+      ;;
+  esac
+}
+
+give_advice "$1" | sed -e '1s/^/WARNING: /' \
+                       -e '2,$s/^/         /' >&2
+
+# Propagate the correct exit status (expected to be 127 for a program
+# not found, 63 for a program that failed due to version mismatch).
+exit $st
+
+# Local variables:
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
diff --git a/extern/libpng/png.5 b/extern/libpng/png.5
new file mode 100644
index 0000000000..c2da95c458
--- /dev/null
+++ b/extern/libpng/png.5
@@ -0,0 +1,84 @@
+.TH PNG 5 "April 14, 2019"
+.SH NAME
+png \- Portable Network Graphics (PNG) format
+
+.SH DESCRIPTION
+PNG (Portable Network Graphics) is an extensible file format for the
+lossless, portable, well-compressed storage of raster images.  PNG
+provides a patent-free replacement for GIF, and can also replace many
+common uses of TIFF. Indexed-color, grayscale, and truecolor images are
+supported, plus an optional alpha channel.  Sample depths range from
+1 to 16 bits.
+.br
+PNG is designed to work well in online viewing applications, such
+as the World Wide Web, so it is fully streamable with a progressive
+display option.  PNG is robust, providing both full file integrity
+checking and fast, simple detection of common transmission errors.
+Also, PNG can store gamma and chromaticity data for improved color
+matching on heterogeneous platforms.
+
+.SH "SEE ALSO"
+.BR "libpng"(3), " libpngpf"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
+.LP
+PNG Specification (Second Edition), November 2003:
+.IP
+.br
+https://www.w3.org/TR/2003/REC-PNG-20031110/
+.LP
+PNG 1.2 Specification, July 1999:
+.IP
+.br
+https://png-mng.sourceforge.io/pub/png/spec/1.2/
+.LP
+PNG 1.0 Specification, October 1996:
+.IP
+.br
+RFC 2083
+.br
+https://www.ietf.org/rfc/rfc2083.txt
+.IP
+.br
+or W3C Recommendation
+.br
+https://www.w3.org/TR/REC-png-961001
+
+.SH AUTHORS
+This man page: Cosmin Truta, Glenn Randers-Pehrson
+.LP
+Portable Network Graphics (PNG) Specification (Second Edition)
+Information technology - Computer graphics and image processing -
+Portable Network Graphics (PNG): Functional specification.
+ISO/IEC 15948:2003 (E) (November 10, 2003): David Duce and others.
+.LP
+Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999):
+Glenn Randers-Pehrson and others (png-list).
+.LP
+Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996):
+Thomas Boutell and others (png-list).
+
+.SH COPYRIGHT
+.LP
+This man page is
+.br
+Copyright (c) 2018-2019 Cosmin Truta.
+.br
+Copyright (c) 1998-2006 Glenn Randers-Pehrson.
+.br
+See png.h for conditions of use and distribution.
+.LP
+The PNG Specification (Second Edition) is
+.br
+Copyright (c) 2003 W3C. (MIT, ERCIM, Keio), All Rights Reserved.
+.LP
+The PNG-1.2 Specification is
+.br
+Copyright (c) 1999 Glenn Randers-Pehrson.
+.br
+See the specification for conditions of use and distribution.
+.LP
+The PNG-1.0 Specification is
+.br
+Copyright (c) 1996 Massachusetts Institute of Technology.
+.br
+See the specification for conditions of use and distribution.
+.\" end of man page
diff --git a/extern/libpng/png.c b/extern/libpng/png.c
new file mode 100644
index 0000000000..757c755f97
--- /dev/null
+++ b/extern/libpng/png.c
@@ -0,0 +1,4607 @@
+
+/* png.c - location for general purpose libpng functions
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+/* Generate a compiler error if there is an old png.h in the search path. */
+typedef png_libpng_version_1_6_37 Your_png_h_is_not_version_1_6_37;
+
+#ifdef __GNUC__
+/* The version tests may need to be added to, but the problem warning has
+ * consistently been fixed in GCC versions which obtain wide-spread release.
+ * The problem is that many versions of GCC rearrange comparison expressions in
+ * the optimizer in such a way that the results of the comparison will change
+ * if signed integer overflow occurs.  Such comparisons are not permitted in
+ * ANSI C90, however GCC isn't clever enough to work out that that do not occur
+ * below in png_ascii_from_fp and png_muldiv, so it produces a warning with
+ * -Wextra.  Unfortunately this is highly dependent on the optimizer and the
+ * machine architecture so the warning comes and goes unpredictably and is
+ * impossible to "fix", even were that a good idea.
+ */
+#if __GNUC__ == 7 && __GNUC_MINOR__ == 1
+#define GCC_STRICT_OVERFLOW 1
+#endif /* GNU 7.1.x */
+#endif /* GNU */
+#ifndef GCC_STRICT_OVERFLOW
+#define GCC_STRICT_OVERFLOW 0
+#endif
+
+/* Tells libpng that we have already handled the first "num_bytes" bytes
+ * of the PNG file signature.  If the PNG data is embedded into another
+ * stream we can set num_bytes = 8 so that libpng will not attempt to read
+ * or write any of the magic bytes before it starts on the IHDR.
+ */
+
+#ifdef PNG_READ_SUPPORTED
+void PNGAPI
+png_set_sig_bytes(png_structrp png_ptr, int num_bytes)
+{
+   unsigned int nb = (unsigned int)num_bytes;
+
+   png_debug(1, "in png_set_sig_bytes");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (num_bytes < 0)
+      nb = 0;
+
+   if (nb > 8)
+      png_error(png_ptr, "Too many bytes for PNG signature");
+
+   png_ptr->sig_bytes = (png_byte)nb;
+}
+
+/* Checks whether the supplied bytes match the PNG signature.  We allow
+ * checking less than the full 8-byte signature so that those apps that
+ * already read the first few bytes of a file to determine the file type
+ * can simply check the remaining bytes for extra assurance.  Returns
+ * an integer less than, equal to, or greater than zero if sig is found,
+ * respectively, to be less than, to match, or be greater than the correct
+ * PNG signature (this is the same behavior as strcmp, memcmp, etc).
+ */
+int PNGAPI
+png_sig_cmp(png_const_bytep sig, size_t start, size_t num_to_check)
+{
+   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+
+   if (num_to_check > 8)
+      num_to_check = 8;
+
+   else if (num_to_check < 1)
+      return (-1);
+
+   if (start > 7)
+      return (-1);
+
+   if (start + num_to_check > 8)
+      num_to_check = 8 - start;
+
+   return ((int)(memcmp(&sig[start], &png_signature[start], num_to_check)));
+}
+
+#endif /* READ */
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Function to allocate memory for zlib */
+PNG_FUNCTION(voidpf /* PRIVATE */,
+png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
+{
+   png_alloc_size_t num_bytes = size;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   if (items >= (~(png_alloc_size_t)0)/size)
+   {
+      png_warning (png_voidcast(png_structrp, png_ptr),
+          "Potential overflow in png_zalloc()");
+      return NULL;
+   }
+
+   num_bytes *= items;
+   return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes);
+}
+
+/* Function to free memory for zlib */
+void /* PRIVATE */
+png_zfree(voidpf png_ptr, voidpf ptr)
+{
+   png_free(png_voidcast(png_const_structrp,png_ptr), ptr);
+}
+
+/* Reset the CRC variable to 32 bits of 1's.  Care must be taken
+ * in case CRC is > 32 bits to leave the top bits 0.
+ */
+void /* PRIVATE */
+png_reset_crc(png_structrp png_ptr)
+{
+   /* The cast is safe because the crc is a 32-bit value. */
+   png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
+}
+
+/* Calculate the CRC over a section of data.  We can only pass as
+ * much data to this routine as the largest single buffer size.  We
+ * also check that this data will actually be used before going to the
+ * trouble of calculating it.
+ */
+void /* PRIVATE */
+png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, size_t length)
+{
+   int need_crc = 1;
+
+   if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
+          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
+         need_crc = 0;
+   }
+
+   else /* critical */
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
+         need_crc = 0;
+   }
+
+   /* 'uLong' is defined in zlib.h as unsigned long; this means that on some
+    * systems it is a 64-bit value.  crc32, however, returns 32 bits so the
+    * following cast is safe.  'uInt' may be no more than 16 bits, so it is
+    * necessary to perform a loop here.
+    */
+   if (need_crc != 0 && length > 0)
+   {
+      uLong crc = png_ptr->crc; /* Should never issue a warning */
+
+      do
+      {
+         uInt safe_length = (uInt)length;
+#ifndef __COVERITY__
+         if (safe_length == 0)
+            safe_length = (uInt)-1; /* evil, but safe */
+#endif
+
+         crc = crc32(crc, ptr, safe_length);
+
+         /* The following should never issue compiler warnings; if they do the
+          * target system has characteristics that will probably violate other
+          * assumptions within the libpng code.
+          */
+         ptr += safe_length;
+         length -= safe_length;
+      }
+      while (length > 0);
+
+      /* And the following is always safe because the crc is only 32 bits. */
+      png_ptr->crc = (png_uint_32)crc;
+   }
+}
+
+/* Check a user supplied version number, called from both read and write
+ * functions that create a png_struct.
+ */
+int
+png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
+{
+   /* Libpng versions 1.0.0 and later are binary compatible if the version
+    * string matches through the second '.'; we must recompile any
+    * applications that use any older library version.
+    */
+
+   if (user_png_ver != NULL)
+   {
+      int i = -1;
+      int found_dots = 0;
+
+      do
+      {
+         i++;
+         if (user_png_ver[i] != PNG_LIBPNG_VER_STRING[i])
+            png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+         if (user_png_ver[i] == '.')
+            found_dots++;
+      } while (found_dots < 2 && user_png_ver[i] != 0 &&
+            PNG_LIBPNG_VER_STRING[i] != 0);
+   }
+
+   else
+      png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+
+   if ((png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) != 0)
+   {
+#ifdef PNG_WARNINGS_SUPPORTED
+      size_t pos = 0;
+      char m[128];
+
+      pos = png_safecat(m, (sizeof m), pos,
+          "Application built with libpng-");
+      pos = png_safecat(m, (sizeof m), pos, user_png_ver);
+      pos = png_safecat(m, (sizeof m), pos, " but running with ");
+      pos = png_safecat(m, (sizeof m), pos, PNG_LIBPNG_VER_STRING);
+      PNG_UNUSED(pos)
+
+      png_warning(png_ptr, m);
+#endif
+
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+      png_ptr->flags = 0;
+#endif
+
+      return 0;
+   }
+
+   /* Success return. */
+   return 1;
+}
+
+/* Generic function to create a png_struct for either read or write - this
+ * contains the common initialization.
+ */
+PNG_FUNCTION(png_structp /* PRIVATE */,
+png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
+{
+   png_struct create_struct;
+#  ifdef PNG_SETJMP_SUPPORTED
+      jmp_buf create_jmp_buf;
+#  endif
+
+   /* This temporary stack-allocated structure is used to provide a place to
+    * build enough context to allow the user provided memory allocator (if any)
+    * to be called.
+    */
+   memset(&create_struct, 0, (sizeof create_struct));
+
+   /* Added at libpng-1.2.6 */
+#  ifdef PNG_USER_LIMITS_SUPPORTED
+      create_struct.user_width_max = PNG_USER_WIDTH_MAX;
+      create_struct.user_height_max = PNG_USER_HEIGHT_MAX;
+
+#     ifdef PNG_USER_CHUNK_CACHE_MAX
+      /* Added at libpng-1.2.43 and 1.4.0 */
+      create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
+#     endif
+
+#     ifdef PNG_USER_CHUNK_MALLOC_MAX
+      /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists
+       * in png_struct regardless.
+       */
+      create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
+#     endif
+#  endif
+
+   /* The following two API calls simply set fields in png_struct, so it is safe
+    * to do them now even though error handling is not yet set up.
+    */
+#  ifdef PNG_USER_MEM_SUPPORTED
+      png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn);
+#  else
+      PNG_UNUSED(mem_ptr)
+      PNG_UNUSED(malloc_fn)
+      PNG_UNUSED(free_fn)
+#  endif
+
+   /* (*error_fn) can return control to the caller after the error_ptr is set,
+    * this will result in a memory leak unless the error_fn does something
+    * extremely sophisticated.  The design lacks merit but is implicit in the
+    * API.
+    */
+   png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn);
+
+#  ifdef PNG_SETJMP_SUPPORTED
+      if (!setjmp(create_jmp_buf))
+#  endif
+      {
+#  ifdef PNG_SETJMP_SUPPORTED
+         /* Temporarily fake out the longjmp information until we have
+          * successfully completed this function.  This only works if we have
+          * setjmp() support compiled in, but it is safe - this stuff should
+          * never happen.
+          */
+         create_struct.jmp_buf_ptr = &create_jmp_buf;
+         create_struct.jmp_buf_size = 0; /*stack allocation*/
+         create_struct.longjmp_fn = longjmp;
+#  endif
+         /* Call the general version checker (shared with read and write code):
+          */
+         if (png_user_version_check(&create_struct, user_png_ver) != 0)
+         {
+            png_structrp png_ptr = png_voidcast(png_structrp,
+                png_malloc_warn(&create_struct, (sizeof *png_ptr)));
+
+            if (png_ptr != NULL)
+            {
+               /* png_ptr->zstream holds a back-pointer to the png_struct, so
+                * this can only be done now:
+                */
+               create_struct.zstream.zalloc = png_zalloc;
+               create_struct.zstream.zfree = png_zfree;
+               create_struct.zstream.opaque = png_ptr;
+
+#              ifdef PNG_SETJMP_SUPPORTED
+               /* Eliminate the local error handling: */
+               create_struct.jmp_buf_ptr = NULL;
+               create_struct.jmp_buf_size = 0;
+               create_struct.longjmp_fn = 0;
+#              endif
+
+               *png_ptr = create_struct;
+
+               /* This is the successful return point */
+               return png_ptr;
+            }
+         }
+      }
+
+   /* A longjmp because of a bug in the application storage allocator or a
+    * simple failure to allocate the png_struct.
+    */
+   return NULL;
+}
+
+/* Allocate the memory for an info_struct for the application. */
+PNG_FUNCTION(png_infop,PNGAPI
+png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED)
+{
+   png_inforp info_ptr;
+
+   png_debug(1, "in png_create_info_struct");
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   /* Use the internal API that does not (or at least should not) error out, so
+    * that this call always returns ok.  The application typically sets up the
+    * error handling *after* creating the info_struct because this is the way it
+    * has always been done in 'example.c'.
+    */
+   info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr,
+       (sizeof *info_ptr)));
+
+   if (info_ptr != NULL)
+      memset(info_ptr, 0, (sizeof *info_ptr));
+
+   return info_ptr;
+}
+
+/* This function frees the memory associated with a single info struct.
+ * Normally, one would use either png_destroy_read_struct() or
+ * png_destroy_write_struct() to free an info struct, but this may be
+ * useful for some applications.  From libpng 1.6.0 this function is also used
+ * internally to implement the png_info release part of the 'struct' destroy
+ * APIs.  This ensures that all possible approaches free the same data (all of
+ * it).
+ */
+void PNGAPI
+png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr)
+{
+   png_inforp info_ptr = NULL;
+
+   png_debug(1, "in png_destroy_info_struct");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (info_ptr_ptr != NULL)
+      info_ptr = *info_ptr_ptr;
+
+   if (info_ptr != NULL)
+   {
+      /* Do this first in case of an error below; if the app implements its own
+       * memory management this can lead to png_free calling png_error, which
+       * will abort this routine and return control to the app error handler.
+       * An infinite loop may result if it then tries to free the same info
+       * ptr.
+       */
+      *info_ptr_ptr = NULL;
+
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
+      memset(info_ptr, 0, (sizeof *info_ptr));
+      png_free(png_ptr, info_ptr);
+   }
+}
+
+/* Initialize the info structure.  This is now an internal function (0.89)
+ * and applications using it are urged to use png_create_info_struct()
+ * instead.  Use deprecated in 1.6.0, internal use removed (used internally it
+ * is just a memset).
+ *
+ * NOTE: it is almost inconceivable that this API is used because it bypasses
+ * the user-memory mechanism and the user error handling/warning mechanisms in
+ * those cases where it does anything other than a memset.
+ */
+PNG_FUNCTION(void,PNGAPI
+png_info_init_3,(png_infopp ptr_ptr, size_t png_info_struct_size),
+    PNG_DEPRECATED)
+{
+   png_inforp info_ptr = *ptr_ptr;
+
+   png_debug(1, "in png_info_init_3");
+
+   if (info_ptr == NULL)
+      return;
+
+   if ((sizeof (png_info)) > png_info_struct_size)
+   {
+      *ptr_ptr = NULL;
+      /* The following line is why this API should not be used: */
+      free(info_ptr);
+      info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL,
+          (sizeof *info_ptr)));
+      if (info_ptr == NULL)
+         return;
+      *ptr_ptr = info_ptr;
+   }
+
+   /* Set everything to 0 */
+   memset(info_ptr, 0, (sizeof *info_ptr));
+}
+
+/* The following API is not called internally */
+void PNGAPI
+png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr,
+    int freer, png_uint_32 mask)
+{
+   png_debug(1, "in png_data_freer");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (freer == PNG_DESTROY_WILL_FREE_DATA)
+      info_ptr->free_me |= mask;
+
+   else if (freer == PNG_USER_WILL_FREE_DATA)
+      info_ptr->free_me &= ~mask;
+
+   else
+      png_error(png_ptr, "Unknown freer parameter in png_data_freer");
+}
+
+void PNGAPI
+png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
+    int num)
+{
+   png_debug(1, "in png_free_data");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+#ifdef PNG_TEXT_SUPPORTED
+   /* Free text item num or (if num == -1) all text items */
+   if (info_ptr->text != NULL &&
+       ((mask & PNG_FREE_TEXT) & info_ptr->free_me) != 0)
+   {
+      if (num != -1)
+      {
+         png_free(png_ptr, info_ptr->text[num].key);
+         info_ptr->text[num].key = NULL;
+      }
+
+      else
+      {
+         int i;
+
+         for (i = 0; i < info_ptr->num_text; i++)
+            png_free(png_ptr, info_ptr->text[i].key);
+
+         png_free(png_ptr, info_ptr->text);
+         info_ptr->text = NULL;
+         info_ptr->num_text = 0;
+         info_ptr->max_text = 0;
+      }
+   }
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+   /* Free any tRNS entry */
+   if (((mask & PNG_FREE_TRNS) & info_ptr->free_me) != 0)
+   {
+      info_ptr->valid &= ~PNG_INFO_tRNS;
+      png_free(png_ptr, info_ptr->trans_alpha);
+      info_ptr->trans_alpha = NULL;
+      info_ptr->num_trans = 0;
+   }
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+   /* Free any sCAL entry */
+   if (((mask & PNG_FREE_SCAL) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->scal_s_width);
+      png_free(png_ptr, info_ptr->scal_s_height);
+      info_ptr->scal_s_width = NULL;
+      info_ptr->scal_s_height = NULL;
+      info_ptr->valid &= ~PNG_INFO_sCAL;
+   }
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+   /* Free any pCAL entry */
+   if (((mask & PNG_FREE_PCAL) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->pcal_purpose);
+      png_free(png_ptr, info_ptr->pcal_units);
+      info_ptr->pcal_purpose = NULL;
+      info_ptr->pcal_units = NULL;
+
+      if (info_ptr->pcal_params != NULL)
+         {
+            int i;
+
+            for (i = 0; i < info_ptr->pcal_nparams; i++)
+               png_free(png_ptr, info_ptr->pcal_params[i]);
+
+            png_free(png_ptr, info_ptr->pcal_params);
+            info_ptr->pcal_params = NULL;
+         }
+      info_ptr->valid &= ~PNG_INFO_pCAL;
+   }
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+   /* Free any profile entry */
+   if (((mask & PNG_FREE_ICCP) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->iccp_name);
+      png_free(png_ptr, info_ptr->iccp_profile);
+      info_ptr->iccp_name = NULL;
+      info_ptr->iccp_profile = NULL;
+      info_ptr->valid &= ~PNG_INFO_iCCP;
+   }
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+   /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
+   if (info_ptr->splt_palettes != NULL &&
+       ((mask & PNG_FREE_SPLT) & info_ptr->free_me) != 0)
+   {
+      if (num != -1)
+      {
+         png_free(png_ptr, info_ptr->splt_palettes[num].name);
+         png_free(png_ptr, info_ptr->splt_palettes[num].entries);
+         info_ptr->splt_palettes[num].name = NULL;
+         info_ptr->splt_palettes[num].entries = NULL;
+      }
+
+      else
+      {
+         int i;
+
+         for (i = 0; i < info_ptr->splt_palettes_num; i++)
+         {
+            png_free(png_ptr, info_ptr->splt_palettes[i].name);
+            png_free(png_ptr, info_ptr->splt_palettes[i].entries);
+         }
+
+         png_free(png_ptr, info_ptr->splt_palettes);
+         info_ptr->splt_palettes = NULL;
+         info_ptr->splt_palettes_num = 0;
+         info_ptr->valid &= ~PNG_INFO_sPLT;
+      }
+   }
+#endif
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+   if (info_ptr->unknown_chunks != NULL &&
+       ((mask & PNG_FREE_UNKN) & info_ptr->free_me) != 0)
+   {
+      if (num != -1)
+      {
+          png_free(png_ptr, info_ptr->unknown_chunks[num].data);
+          info_ptr->unknown_chunks[num].data = NULL;
+      }
+
+      else
+      {
+         int i;
+
+         for (i = 0; i < info_ptr->unknown_chunks_num; i++)
+            png_free(png_ptr, info_ptr->unknown_chunks[i].data);
+
+         png_free(png_ptr, info_ptr->unknown_chunks);
+         info_ptr->unknown_chunks = NULL;
+         info_ptr->unknown_chunks_num = 0;
+      }
+   }
+#endif
+
+#ifdef PNG_eXIf_SUPPORTED
+   /* Free any eXIf entry */
+   if (((mask & PNG_FREE_EXIF) & info_ptr->free_me) != 0)
+   {
+# ifdef PNG_READ_eXIf_SUPPORTED
+      if (info_ptr->eXIf_buf)
+      {
+         png_free(png_ptr, info_ptr->eXIf_buf);
+         info_ptr->eXIf_buf = NULL;
+      }
+# endif
+      if (info_ptr->exif)
+      {
+         png_free(png_ptr, info_ptr->exif);
+         info_ptr->exif = NULL;
+      }
+      info_ptr->valid &= ~PNG_INFO_eXIf;
+   }
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+   /* Free any hIST entry */
+   if (((mask & PNG_FREE_HIST) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->hist);
+      info_ptr->hist = NULL;
+      info_ptr->valid &= ~PNG_INFO_hIST;
+   }
+#endif
+
+   /* Free any PLTE entry that was internally allocated */
+   if (((mask & PNG_FREE_PLTE) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->palette);
+      info_ptr->palette = NULL;
+      info_ptr->valid &= ~PNG_INFO_PLTE;
+      info_ptr->num_palette = 0;
+   }
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+   /* Free any image bits attached to the info structure */
+   if (((mask & PNG_FREE_ROWS) & info_ptr->free_me) != 0)
+   {
+      if (info_ptr->row_pointers != NULL)
+      {
+         png_uint_32 row;
+         for (row = 0; row < info_ptr->height; row++)
+            png_free(png_ptr, info_ptr->row_pointers[row]);
+
+         png_free(png_ptr, info_ptr->row_pointers);
+         info_ptr->row_pointers = NULL;
+      }
+      info_ptr->valid &= ~PNG_INFO_IDAT;
+   }
+#endif
+
+   if (num != -1)
+      mask &= ~PNG_FREE_MUL;
+
+   info_ptr->free_me &= ~mask;
+}
+#endif /* READ || WRITE */
+
+/* This function returns a pointer to the io_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy() or png_read_destroy() are called.
+ */
+png_voidp PNGAPI
+png_get_io_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return (NULL);
+
+   return (png_ptr->io_ptr);
+}
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+#  ifdef PNG_STDIO_SUPPORTED
+/* Initialize the default input/output functions for the PNG file.  If you
+ * use your own read or write routines, you can call either png_set_read_fn()
+ * or png_set_write_fn() instead of png_init_io().  If you have defined
+ * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
+ * function of your own because "FILE *" isn't necessarily available.
+ */
+void PNGAPI
+png_init_io(png_structrp png_ptr, png_FILE_p fp)
+{
+   png_debug(1, "in png_init_io");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->io_ptr = (png_voidp)fp;
+}
+#  endif
+
+#  ifdef PNG_SAVE_INT_32_SUPPORTED
+/* PNG signed integers are saved in 32-bit 2's complement format.  ANSI C-90
+ * defines a cast of a signed integer to an unsigned integer either to preserve
+ * the value, if it is positive, or to calculate:
+ *
+ *     (UNSIGNED_MAX+1) + integer
+ *
+ * Where UNSIGNED_MAX is the appropriate maximum unsigned value, so when the
+ * negative integral value is added the result will be an unsigned value
+ * correspnding to the 2's complement representation.
+ */
+void PNGAPI
+png_save_int_32(png_bytep buf, png_int_32 i)
+{
+   png_save_uint_32(buf, (png_uint_32)i);
+}
+#  endif
+
+#  ifdef PNG_TIME_RFC1123_SUPPORTED
+/* Convert the supplied time into an RFC 1123 string suitable for use in
+ * a "Creation Time" or other text-based time string.
+ */
+int PNGAPI
+png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime)
+{
+   static const char short_months[12][4] =
+        {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
+
+   if (out == NULL)
+      return 0;
+
+   if (ptime->year > 9999 /* RFC1123 limitation */ ||
+       ptime->month == 0    ||  ptime->month > 12  ||
+       ptime->day   == 0    ||  ptime->day   > 31  ||
+       ptime->hour  > 23    ||  ptime->minute > 59 ||
+       ptime->second > 60)
+      return 0;
+
+   {
+      size_t pos = 0;
+      char number_buf[5]; /* enough for a four-digit year */
+
+#     define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string))
+#     define APPEND_NUMBER(format, value)\
+         APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
+#     define APPEND(ch) if (pos < 28) out[pos++] = (ch)
+
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
+      APPEND(' ');
+      APPEND_STRING(short_months[(ptime->month - 1)]);
+      APPEND(' ');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
+      APPEND(' ');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
+      APPEND(':');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
+      APPEND(':');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
+      APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
+      PNG_UNUSED (pos)
+
+#     undef APPEND
+#     undef APPEND_NUMBER
+#     undef APPEND_STRING
+   }
+
+   return 1;
+}
+
+#    if PNG_LIBPNG_VER < 10700
+/* To do: remove the following from libpng-1.7 */
+/* Original API that uses a private buffer in png_struct.
+ * Deprecated because it causes png_struct to carry a spurious temporary
+ * buffer (png_struct::time_buffer), better to have the caller pass this in.
+ */
+png_const_charp PNGAPI
+png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime)
+{
+   if (png_ptr != NULL)
+   {
+      /* The only failure above if png_ptr != NULL is from an invalid ptime */
+      if (png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime) == 0)
+         png_warning(png_ptr, "Ignoring invalid time value");
+
+      else
+         return png_ptr->time_buffer;
+   }
+
+   return NULL;
+}
+#    endif /* LIBPNG_VER < 10700 */
+#  endif /* TIME_RFC1123 */
+
+#endif /* READ || WRITE */
+
+png_const_charp PNGAPI
+png_get_copyright(png_const_structrp png_ptr)
+{
+   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
+#ifdef PNG_STRING_COPYRIGHT
+   return PNG_STRING_COPYRIGHT
+#else
+   return PNG_STRING_NEWLINE \
+      "libpng version 1.6.37" PNG_STRING_NEWLINE \
+      "Copyright (c) 2018-2019 Cosmin Truta" PNG_STRING_NEWLINE \
+      "Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson" \
+      PNG_STRING_NEWLINE \
+      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
+      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
+      PNG_STRING_NEWLINE;
+#endif
+}
+
+/* The following return the library version as a short string in the
+ * format 1.0.0 through 99.99.99zz.  To get the version of *.h files
+ * used with your application, print out PNG_LIBPNG_VER_STRING, which
+ * is defined in png.h.
+ * Note: now there is no difference between png_get_libpng_ver() and
+ * png_get_header_ver().  Due to the version_nn_nn_nn typedef guard,
+ * it is guaranteed that png.c uses the correct version of png.h.
+ */
+png_const_charp PNGAPI
+png_get_libpng_ver(png_const_structrp png_ptr)
+{
+   /* Version of *.c files used when building libpng */
+   return png_get_header_ver(png_ptr);
+}
+
+png_const_charp PNGAPI
+png_get_header_ver(png_const_structrp png_ptr)
+{
+   /* Version of *.h files used when building libpng */
+   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
+   return PNG_LIBPNG_VER_STRING;
+}
+
+png_const_charp PNGAPI
+png_get_header_version(png_const_structrp png_ptr)
+{
+   /* Returns longer string containing both version and date */
+   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
+#ifdef __STDC__
+   return PNG_HEADER_VERSION_STRING
+#  ifndef PNG_READ_SUPPORTED
+      " (NO READ SUPPORT)"
+#  endif
+      PNG_STRING_NEWLINE;
+#else
+   return PNG_HEADER_VERSION_STRING;
+#endif
+}
+
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+/* NOTE: this routine is not used internally! */
+/* Build a grayscale palette.  Palette is assumed to be 1 << bit_depth
+ * large of png_color.  This lets grayscale images be treated as
+ * paletted.  Most useful for gamma correction and simplification
+ * of code.  This API is not used internally.
+ */
+void PNGAPI
+png_build_grayscale_palette(int bit_depth, png_colorp palette)
+{
+   int num_palette;
+   int color_inc;
+   int i;
+   int v;
+
+   png_debug(1, "in png_do_build_grayscale_palette");
+
+   if (palette == NULL)
+      return;
+
+   switch (bit_depth)
+   {
+      case 1:
+         num_palette = 2;
+         color_inc = 0xff;
+         break;
+
+      case 2:
+         num_palette = 4;
+         color_inc = 0x55;
+         break;
+
+      case 4:
+         num_palette = 16;
+         color_inc = 0x11;
+         break;
+
+      case 8:
+         num_palette = 256;
+         color_inc = 1;
+         break;
+
+      default:
+         num_palette = 0;
+         color_inc = 0;
+         break;
+   }
+
+   for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
+   {
+      palette[i].red = (png_byte)(v & 0xff);
+      palette[i].green = (png_byte)(v & 0xff);
+      palette[i].blue = (png_byte)(v & 0xff);
+   }
+}
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+int PNGAPI
+png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)
+{
+   /* Check chunk_name and return "keep" value if it's on the list, else 0 */
+   png_const_bytep p, p_end;
+
+   if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0)
+      return PNG_HANDLE_CHUNK_AS_DEFAULT;
+
+   p_end = png_ptr->chunk_list;
+   p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
+
+   /* The code is the fifth byte after each four byte string.  Historically this
+    * code was always searched from the end of the list, this is no longer
+    * necessary because the 'set' routine handles duplicate entries correctly.
+    */
+   do /* num_chunk_list > 0, so at least one */
+   {
+      p -= 5;
+
+      if (memcmp(chunk_name, p, 4) == 0)
+         return p[4];
+   }
+   while (p > p_end);
+
+   /* This means that known chunks should be processed and unknown chunks should
+    * be handled according to the value of png_ptr->unknown_default; this can be
+    * confusing because, as a result, there are two levels of defaulting for
+    * unknown chunks.
+    */
+   return PNG_HANDLE_CHUNK_AS_DEFAULT;
+}
+
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
+   defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+int /* PRIVATE */
+png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name)
+{
+   png_byte chunk_string[5];
+
+   PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
+   return png_handle_as_unknown(png_ptr, chunk_string);
+}
+#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
+#endif /* SET_UNKNOWN_CHUNKS */
+
+#ifdef PNG_READ_SUPPORTED
+/* This function, added to libpng-1.0.6g, is untested. */
+int PNGAPI
+png_reset_zstream(png_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return Z_STREAM_ERROR;
+
+   /* WARNING: this resets the window bits to the maximum! */
+   return (inflateReset(&png_ptr->zstream));
+}
+#endif /* READ */
+
+/* This function was added to libpng-1.0.7 */
+png_uint_32 PNGAPI
+png_access_version_number(void)
+{
+   /* Version of *.c files used when building libpng */
+   return((png_uint_32)PNG_LIBPNG_VER);
+}
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Ensure that png_ptr->zstream.msg holds some appropriate error message string.
+ * If it doesn't 'ret' is used to set it to something appropriate, even in cases
+ * like Z_OK or Z_STREAM_END where the error code is apparently a success code.
+ */
+void /* PRIVATE */
+png_zstream_error(png_structrp png_ptr, int ret)
+{
+   /* Translate 'ret' into an appropriate error string, priority is given to the
+    * one in zstream if set.  This always returns a string, even in cases like
+    * Z_OK or Z_STREAM_END where the error code is a success code.
+    */
+   if (png_ptr->zstream.msg == NULL) switch (ret)
+   {
+      default:
+      case Z_OK:
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code");
+         break;
+
+      case Z_STREAM_END:
+         /* Normal exit */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream");
+         break;
+
+      case Z_NEED_DICT:
+         /* This means the deflate stream did not have a dictionary; this
+          * indicates a bogus PNG.
+          */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary");
+         break;
+
+      case Z_ERRNO:
+         /* gz APIs only: should not happen */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error");
+         break;
+
+      case Z_STREAM_ERROR:
+         /* internal libpng error */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib");
+         break;
+
+      case Z_DATA_ERROR:
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream");
+         break;
+
+      case Z_MEM_ERROR:
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory");
+         break;
+
+      case Z_BUF_ERROR:
+         /* End of input or output; not a problem if the caller is doing
+          * incremental read or write.
+          */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated");
+         break;
+
+      case Z_VERSION_ERROR:
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version");
+         break;
+
+      case PNG_UNEXPECTED_ZLIB_RETURN:
+         /* Compile errors here mean that zlib now uses the value co-opted in
+          * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above
+          * and change pngpriv.h.  Note that this message is "... return",
+          * whereas the default/Z_OK one is "... return code".
+          */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return");
+         break;
+   }
+}
+
+/* png_convert_size: a PNGAPI but no longer in png.h, so deleted
+ * at libpng 1.5.5!
+ */
+
+/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
+#ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */
+static int
+png_colorspace_check_gamma(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, png_fixed_point gAMA, int from)
+   /* This is called to check a new gamma value against an existing one.  The
+    * routine returns false if the new gamma value should not be written.
+    *
+    * 'from' says where the new gamma value comes from:
+    *
+    *    0: the new gamma value is the libpng estimate for an ICC profile
+    *    1: the new gamma value comes from a gAMA chunk
+    *    2: the new gamma value comes from an sRGB chunk
+    */
+{
+   png_fixed_point gtest;
+
+   if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+       (png_muldiv(&gtest, colorspace->gamma, PNG_FP_1, gAMA) == 0  ||
+      png_gamma_significant(gtest) != 0))
+   {
+      /* Either this is an sRGB image, in which case the calculated gamma
+       * approximation should match, or this is an image with a profile and the
+       * value libpng calculates for the gamma of the profile does not match the
+       * value recorded in the file.  The former, sRGB, case is an error, the
+       * latter is just a warning.
+       */
+      if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2)
+      {
+         png_chunk_report(png_ptr, "gamma value does not match sRGB",
+             PNG_CHUNK_ERROR);
+         /* Do not overwrite an sRGB value */
+         return from == 2;
+      }
+
+      else /* sRGB tag not involved */
+      {
+         png_chunk_report(png_ptr, "gamma value does not match libpng estimate",
+             PNG_CHUNK_WARNING);
+         return from == 1;
+      }
+   }
+
+   return 1;
+}
+
+void /* PRIVATE */
+png_colorspace_set_gamma(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, png_fixed_point gAMA)
+{
+   /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
+    * occur.  Since the fixed point representation is asymmetrical it is
+    * possible for 1/gamma to overflow the limit of 21474 and this means the
+    * gamma value must be at least 5/100000 and hence at most 20000.0.  For
+    * safety the limits here are a little narrower.  The values are 0.00016 to
+    * 6250.0, which are truly ridiculous gamma values (and will produce
+    * displays that are all black or all white.)
+    *
+    * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk
+    * handling code, which only required the value to be >0.
+    */
+   png_const_charp errmsg;
+
+   if (gAMA < 16 || gAMA > 625000000)
+      errmsg = "gamma value out of range";
+
+#  ifdef PNG_READ_gAMA_SUPPORTED
+   /* Allow the application to set the gamma value more than once */
+   else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+      (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0)
+      errmsg = "duplicate";
+#  endif
+
+   /* Do nothing if the colorspace is already invalid */
+   else if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+      return;
+
+   else
+   {
+      if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA,
+          1/*from gAMA*/) != 0)
+      {
+         /* Store this gamma value. */
+         colorspace->gamma = gAMA;
+         colorspace->flags |=
+            (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA);
+      }
+
+      /* At present if the check_gamma test fails the gamma of the colorspace is
+       * not updated however the colorspace is not invalidated.  This
+       * corresponds to the case where the existing gamma comes from an sRGB
+       * chunk or profile.  An error message has already been output.
+       */
+      return;
+   }
+
+   /* Error exit - errmsg has been set. */
+   colorspace->flags |= PNG_COLORSPACE_INVALID;
+   png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR);
+}
+
+void /* PRIVATE */
+png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr)
+{
+   if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+   {
+      /* Everything is invalid */
+      info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB|
+         PNG_INFO_iCCP);
+
+#     ifdef PNG_COLORSPACE_SUPPORTED
+      /* Clean up the iCCP profile now if it won't be used. */
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/);
+#     else
+      PNG_UNUSED(png_ptr)
+#     endif
+   }
+
+   else
+   {
+#     ifdef PNG_COLORSPACE_SUPPORTED
+      /* Leave the INFO_iCCP flag set if the pngset.c code has already set
+       * it; this allows a PNG to contain a profile which matches sRGB and
+       * yet still have that profile retrievable by the application.
+       */
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) != 0)
+         info_ptr->valid |= PNG_INFO_sRGB;
+
+      else
+         info_ptr->valid &= ~PNG_INFO_sRGB;
+
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+         info_ptr->valid |= PNG_INFO_cHRM;
+
+      else
+         info_ptr->valid &= ~PNG_INFO_cHRM;
+#     endif
+
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0)
+         info_ptr->valid |= PNG_INFO_gAMA;
+
+      else
+         info_ptr->valid &= ~PNG_INFO_gAMA;
+   }
+}
+
+#ifdef PNG_READ_SUPPORTED
+void /* PRIVATE */
+png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr)
+{
+   if (info_ptr == NULL) /* reduce code size; check here not in the caller */
+      return;
+
+   info_ptr->colorspace = png_ptr->colorspace;
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+#endif
+#endif /* GAMMA */
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+/* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
+ * cHRM, as opposed to using chromaticities.  These internal APIs return
+ * non-zero on a parameter error.  The X, Y and Z values are required to be
+ * positive and less than 1.0.
+ */
+static int
+png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ)
+{
+   png_int_32 d, dwhite, whiteX, whiteY;
+
+   d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z;
+   if (png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d) == 0)
+      return 1;
+   if (png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d) == 0)
+      return 1;
+   dwhite = d;
+   whiteX = XYZ->red_X;
+   whiteY = XYZ->red_Y;
+
+   d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z;
+   if (png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d) == 0)
+      return 1;
+   if (png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d) == 0)
+      return 1;
+   dwhite += d;
+   whiteX += XYZ->green_X;
+   whiteY += XYZ->green_Y;
+
+   d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z;
+   if (png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d) == 0)
+      return 1;
+   if (png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d) == 0)
+      return 1;
+   dwhite += d;
+   whiteX += XYZ->blue_X;
+   whiteY += XYZ->blue_Y;
+
+   /* The reference white is simply the sum of the end-point (X,Y,Z) vectors,
+    * thus:
+    */
+   if (png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite) == 0)
+      return 1;
+   if (png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite) == 0)
+      return 1;
+
+   return 0;
+}
+
+static int
+png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
+{
+   png_fixed_point red_inverse, green_inverse, blue_scale;
+   png_fixed_point left, right, denominator;
+
+   /* Check xy and, implicitly, z.  Note that wide gamut color spaces typically
+    * have end points with 0 tristimulus values (these are impossible end
+    * points, but they are used to cover the possible colors).  We check
+    * xy->whitey against 5, not 0, to avoid a possible integer overflow.
+    */
+   if (xy->redx   < 0 || xy->redx > PNG_FP_1) return 1;
+   if (xy->redy   < 0 || xy->redy > PNG_FP_1-xy->redx) return 1;
+   if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1;
+   if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1;
+   if (xy->bluex  < 0 || xy->bluex > PNG_FP_1) return 1;
+   if (xy->bluey  < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1;
+   if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1;
+   if (xy->whitey < 5 || xy->whitey > PNG_FP_1-xy->whitex) return 1;
+
+   /* The reverse calculation is more difficult because the original tristimulus
+    * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
+    * derived values were recorded in the cHRM chunk;
+    * (red,green,blue,white)x(x,y).  This loses one degree of freedom and
+    * therefore an arbitrary ninth value has to be introduced to undo the
+    * original transformations.
+    *
+    * Think of the original end-points as points in (X,Y,Z) space.  The
+    * chromaticity values (c) have the property:
+    *
+    *           C
+    *   c = ---------
+    *       X + Y + Z
+    *
+    * For each c (x,y,z) from the corresponding original C (X,Y,Z).  Thus the
+    * three chromaticity values (x,y,z) for each end-point obey the
+    * relationship:
+    *
+    *   x + y + z = 1
+    *
+    * This describes the plane in (X,Y,Z) space that intersects each axis at the
+    * value 1.0; call this the chromaticity plane.  Thus the chromaticity
+    * calculation has scaled each end-point so that it is on the x+y+z=1 plane
+    * and chromaticity is the intersection of the vector from the origin to the
+    * (X,Y,Z) value with the chromaticity plane.
+    *
+    * To fully invert the chromaticity calculation we would need the three
+    * end-point scale factors, (red-scale, green-scale, blue-scale), but these
+    * were not recorded.  Instead we calculated the reference white (X,Y,Z) and
+    * recorded the chromaticity of this.  The reference white (X,Y,Z) would have
+    * given all three of the scale factors since:
+    *
+    *    color-C = color-c * color-scale
+    *    white-C = red-C + green-C + blue-C
+    *            = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+    *
+    * But cHRM records only white-x and white-y, so we have lost the white scale
+    * factor:
+    *
+    *    white-C = white-c*white-scale
+    *
+    * To handle this the inverse transformation makes an arbitrary assumption
+    * about white-scale:
+    *
+    *    Assume: white-Y = 1.0
+    *    Hence:  white-scale = 1/white-y
+    *    Or:     red-Y + green-Y + blue-Y = 1.0
+    *
+    * Notice the last statement of the assumption gives an equation in three of
+    * the nine values we want to calculate.  8 more equations come from the
+    * above routine as summarised at the top above (the chromaticity
+    * calculation):
+    *
+    *    Given: color-x = color-X / (color-X + color-Y + color-Z)
+    *    Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0
+    *
+    * This is 9 simultaneous equations in the 9 variables "color-C" and can be
+    * solved by Cramer's rule.  Cramer's rule requires calculating 10 9x9 matrix
+    * determinants, however this is not as bad as it seems because only 28 of
+    * the total of 90 terms in the various matrices are non-zero.  Nevertheless
+    * Cramer's rule is notoriously numerically unstable because the determinant
+    * calculation involves the difference of large, but similar, numbers.  It is
+    * difficult to be sure that the calculation is stable for real world values
+    * and it is certain that it becomes unstable where the end points are close
+    * together.
+    *
+    * So this code uses the perhaps slightly less optimal but more
+    * understandable and totally obvious approach of calculating color-scale.
+    *
+    * This algorithm depends on the precision in white-scale and that is
+    * (1/white-y), so we can immediately see that as white-y approaches 0 the
+    * accuracy inherent in the cHRM chunk drops off substantially.
+    *
+    * libpng arithmetic: a simple inversion of the above equations
+    * ------------------------------------------------------------
+    *
+    *    white_scale = 1/white-y
+    *    white-X = white-x * white-scale
+    *    white-Y = 1.0
+    *    white-Z = (1 - white-x - white-y) * white_scale
+    *
+    *    white-C = red-C + green-C + blue-C
+    *            = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+    *
+    * This gives us three equations in (red-scale,green-scale,blue-scale) where
+    * all the coefficients are now known:
+    *
+    *    red-x*red-scale + green-x*green-scale + blue-x*blue-scale
+    *       = white-x/white-y
+    *    red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1
+    *    red-z*red-scale + green-z*green-scale + blue-z*blue-scale
+    *       = (1 - white-x - white-y)/white-y
+    *
+    * In the last equation color-z is (1 - color-x - color-y) so we can add all
+    * three equations together to get an alternative third:
+    *
+    *    red-scale + green-scale + blue-scale = 1/white-y = white-scale
+    *
+    * So now we have a Cramer's rule solution where the determinants are just
+    * 3x3 - far more tractible.  Unfortunately 3x3 determinants still involve
+    * multiplication of three coefficients so we can't guarantee to avoid
+    * overflow in the libpng fixed point representation.  Using Cramer's rule in
+    * floating point is probably a good choice here, but it's not an option for
+    * fixed point.  Instead proceed to simplify the first two equations by
+    * eliminating what is likely to be the largest value, blue-scale:
+    *
+    *    blue-scale = white-scale - red-scale - green-scale
+    *
+    * Hence:
+    *
+    *    (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale =
+    *                (white-x - blue-x)*white-scale
+    *
+    *    (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale =
+    *                1 - blue-y*white-scale
+    *
+    * And now we can trivially solve for (red-scale,green-scale):
+    *
+    *    green-scale =
+    *                (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale
+    *                -----------------------------------------------------------
+    *                                  green-x - blue-x
+    *
+    *    red-scale =
+    *                1 - blue-y*white-scale - (green-y - blue-y) * green-scale
+    *                ---------------------------------------------------------
+    *                                  red-y - blue-y
+    *
+    * Hence:
+    *
+    *    red-scale =
+    *          ( (green-x - blue-x) * (white-y - blue-y) -
+    *            (green-y - blue-y) * (white-x - blue-x) ) / white-y
+    * -------------------------------------------------------------------------
+    *  (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+    *
+    *    green-scale =
+    *          ( (red-y - blue-y) * (white-x - blue-x) -
+    *            (red-x - blue-x) * (white-y - blue-y) ) / white-y
+    * -------------------------------------------------------------------------
+    *  (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+    *
+    * Accuracy:
+    * The input values have 5 decimal digits of accuracy.  The values are all in
+    * the range 0 < value < 1, so simple products are in the same range but may
+    * need up to 10 decimal digits to preserve the original precision and avoid
+    * underflow.  Because we are using a 32-bit signed representation we cannot
+    * match this; the best is a little over 9 decimal digits, less than 10.
+    *
+    * The approach used here is to preserve the maximum precision within the
+    * signed representation.  Because the red-scale calculation above uses the
+    * difference between two products of values that must be in the range -1..+1
+    * it is sufficient to divide the product by 7; ceil(100,000/32767*2).  The
+    * factor is irrelevant in the calculation because it is applied to both
+    * numerator and denominator.
+    *
+    * Note that the values of the differences of the products of the
+    * chromaticities in the above equations tend to be small, for example for
+    * the sRGB chromaticities they are:
+    *
+    * red numerator:    -0.04751
+    * green numerator:  -0.08788
+    * denominator:      -0.2241 (without white-y multiplication)
+    *
+    *  The resultant Y coefficients from the chromaticities of some widely used
+    *  color space definitions are (to 15 decimal places):
+    *
+    *  sRGB
+    *    0.212639005871510 0.715168678767756 0.072192315360734
+    *  Kodak ProPhoto
+    *    0.288071128229293 0.711843217810102 0.000085653960605
+    *  Adobe RGB
+    *    0.297344975250536 0.627363566255466 0.075291458493998
+    *  Adobe Wide Gamut RGB
+    *    0.258728243040113 0.724682314948566 0.016589442011321
+    */
+   /* By the argument, above overflow should be impossible here. The return
+    * value of 2 indicates an internal error to the caller.
+    */
+   if (png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7) == 0)
+      return 2;
+   if (png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7) == 0)
+      return 2;
+   denominator = left - right;
+
+   /* Now find the red numerator. */
+   if (png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
+      return 2;
+   if (png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
+      return 2;
+
+   /* Overflow is possible here and it indicates an extreme set of PNG cHRM
+    * chunk values.  This calculation actually returns the reciprocal of the
+    * scale value because this allows us to delay the multiplication of white-y
+    * into the denominator, which tends to produce a small number.
+    */
+   if (png_muldiv(&red_inverse, xy->whitey, denominator, left-right) == 0 ||
+       red_inverse <= xy->whitey /* r+g+b scales = white scale */)
+      return 1;
+
+   /* Similarly for green_inverse: */
+   if (png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
+      return 2;
+   if (png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
+      return 2;
+   if (png_muldiv(&green_inverse, xy->whitey, denominator, left-right) == 0 ||
+       green_inverse <= xy->whitey)
+      return 1;
+
+   /* And the blue scale, the checks above guarantee this can't overflow but it
+    * can still produce 0 for extreme cHRM values.
+    */
+   blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) -
+       png_reciprocal(green_inverse);
+   if (blue_scale <= 0)
+      return 1;
+
+
+   /* And fill in the png_XYZ: */
+   if (png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1,
+       red_inverse) == 0)
+      return 1;
+
+   if (png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1,
+       green_inverse) == 0)
+      return 1;
+
+   if (png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale,
+       PNG_FP_1) == 0)
+      return 1;
+
+   return 0; /*success*/
+}
+
+static int
+png_XYZ_normalize(png_XYZ *XYZ)
+{
+   png_int_32 Y;
+
+   if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 ||
+      XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 ||
+      XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0)
+      return 1;
+
+   /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1.
+    * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore
+    * relying on addition of two positive values producing a negative one is not
+    * safe.
+    */
+   Y = XYZ->red_Y;
+   if (0x7fffffff - Y < XYZ->green_X)
+      return 1;
+   Y += XYZ->green_Y;
+   if (0x7fffffff - Y < XYZ->blue_X)
+      return 1;
+   Y += XYZ->blue_Y;
+
+   if (Y != PNG_FP_1)
+   {
+      if (png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y) == 0)
+         return 1;
+
+      if (png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y) == 0)
+         return 1;
+
+      if (png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y) == 0)
+         return 1;
+   }
+
+   return 0;
+}
+
+static int
+png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta)
+{
+   /* Allow an error of +/-0.01 (absolute value) on each chromaticity */
+   if (PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) ||
+       PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) ||
+       PNG_OUT_OF_RANGE(xy1->redx,   xy2->redx,  delta) ||
+       PNG_OUT_OF_RANGE(xy1->redy,   xy2->redy,  delta) ||
+       PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) ||
+       PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) ||
+       PNG_OUT_OF_RANGE(xy1->bluex,  xy2->bluex, delta) ||
+       PNG_OUT_OF_RANGE(xy1->bluey,  xy2->bluey, delta))
+      return 0;
+   return 1;
+}
+
+/* Added in libpng-1.6.0, a different check for the validity of a set of cHRM
+ * chunk chromaticities.  Earlier checks used to simply look for the overflow
+ * condition (where the determinant of the matrix to solve for XYZ ends up zero
+ * because the chromaticity values are not all distinct.)  Despite this it is
+ * theoretically possible to produce chromaticities that are apparently valid
+ * but that rapidly degrade to invalid, potentially crashing, sets because of
+ * arithmetic inaccuracies when calculations are performed on them.  The new
+ * check is to round-trip xy -> XYZ -> xy and then check that the result is
+ * within a small percentage of the original.
+ */
+static int
+png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy)
+{
+   int result;
+   png_xy xy_test;
+
+   /* As a side-effect this routine also returns the XYZ endpoints. */
+   result = png_XYZ_from_xy(XYZ, xy);
+   if (result != 0)
+      return result;
+
+   result = png_xy_from_XYZ(&xy_test, XYZ);
+   if (result != 0)
+      return result;
+
+   if (png_colorspace_endpoints_match(xy, &xy_test,
+       5/*actually, the math is pretty accurate*/) != 0)
+      return 0;
+
+   /* Too much slip */
+   return 1;
+}
+
+/* This is the check going the other way.  The XYZ is modified to normalize it
+ * (another side-effect) and the xy chromaticities are returned.
+ */
+static int
+png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ)
+{
+   int result;
+   png_XYZ XYZtemp;
+
+   result = png_XYZ_normalize(XYZ);
+   if (result != 0)
+      return result;
+
+   result = png_xy_from_XYZ(xy, XYZ);
+   if (result != 0)
+      return result;
+
+   XYZtemp = *XYZ;
+   return png_colorspace_check_xy(&XYZtemp, xy);
+}
+
+/* Used to check for an endpoint match against sRGB */
+static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */
+{
+   /* color      x       y */
+   /* red   */ 64000, 33000,
+   /* green */ 30000, 60000,
+   /* blue  */ 15000,  6000,
+   /* white */ 31270, 32900
+};
+
+static int
+png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ,
+    int preferred)
+{
+   if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+      return 0;
+
+   /* The consistency check is performed on the chromaticities; this factors out
+    * variations because of the normalization (or not) of the end point Y
+    * values.
+    */
+   if (preferred < 2 &&
+       (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      /* The end points must be reasonably close to any we already have.  The
+       * following allows an error of up to +/-.001
+       */
+      if (png_colorspace_endpoints_match(xy, &colorspace->end_points_xy,
+          100) == 0)
+      {
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_benign_error(png_ptr, "inconsistent chromaticities");
+         return 0; /* failed */
+      }
+
+      /* Only overwrite with preferred values */
+      if (preferred == 0)
+         return 1; /* ok, but no change */
+   }
+
+   colorspace->end_points_xy = *xy;
+   colorspace->end_points_XYZ = *XYZ;
+   colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS;
+
+   /* The end points are normally quoted to two decimal digits, so allow +/-0.01
+    * on this test.
+    */
+   if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000) != 0)
+      colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB;
+
+   else
+      colorspace->flags &= PNG_COLORSPACE_CANCEL(
+         PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
+
+   return 2; /* ok and changed */
+}
+
+int /* PRIVATE */
+png_colorspace_set_chromaticities(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, const png_xy *xy, int preferred)
+{
+   /* We must check the end points to ensure they are reasonable - in the past
+    * color management systems have crashed as a result of getting bogus
+    * colorant values, while this isn't the fault of libpng it is the
+    * responsibility of libpng because PNG carries the bomb and libpng is in a
+    * position to protect against it.
+    */
+   png_XYZ XYZ;
+
+   switch (png_colorspace_check_xy(&XYZ, xy))
+   {
+      case 0: /* success */
+         return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ,
+             preferred);
+
+      case 1:
+         /* We can't invert the chromaticities so we can't produce value XYZ
+          * values.  Likely as not a color management system will fail too.
+          */
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_benign_error(png_ptr, "invalid chromaticities");
+         break;
+
+      default:
+         /* libpng is broken; this should be a warning but if it happens we
+          * want error reports so for the moment it is an error.
+          */
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_error(png_ptr, "internal error checking chromaticities");
+   }
+
+   return 0; /* failed */
+}
+
+int /* PRIVATE */
+png_colorspace_set_endpoints(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred)
+{
+   png_XYZ XYZ = *XYZ_in;
+   png_xy xy;
+
+   switch (png_colorspace_check_XYZ(&xy, &XYZ))
+   {
+      case 0:
+         return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ,
+             preferred);
+
+      case 1:
+         /* End points are invalid. */
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_benign_error(png_ptr, "invalid end points");
+         break;
+
+      default:
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_error(png_ptr, "internal error checking chromaticities");
+   }
+
+   return 0; /* failed */
+}
+
+#if defined(PNG_sRGB_SUPPORTED) || defined(PNG_iCCP_SUPPORTED)
+/* Error message generation */
+static char
+png_icc_tag_char(png_uint_32 byte)
+{
+   byte &= 0xff;
+   if (byte >= 32 && byte <= 126)
+      return (char)byte;
+   else
+      return '?';
+}
+
+static void
+png_icc_tag_name(char *name, png_uint_32 tag)
+{
+   name[0] = '\'';
+   name[1] = png_icc_tag_char(tag >> 24);
+   name[2] = png_icc_tag_char(tag >> 16);
+   name[3] = png_icc_tag_char(tag >>  8);
+   name[4] = png_icc_tag_char(tag      );
+   name[5] = '\'';
+}
+
+static int
+is_ICC_signature_char(png_alloc_size_t it)
+{
+   return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) ||
+      (it >= 97 && it <= 122);
+}
+
+static int
+is_ICC_signature(png_alloc_size_t it)
+{
+   return is_ICC_signature_char(it >> 24) /* checks all the top bits */ &&
+      is_ICC_signature_char((it >> 16) & 0xff) &&
+      is_ICC_signature_char((it >> 8) & 0xff) &&
+      is_ICC_signature_char(it & 0xff);
+}
+
+static int
+png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_alloc_size_t value, png_const_charp reason)
+{
+   size_t pos;
+   char message[196]; /* see below for calculation */
+
+   if (colorspace != NULL)
+      colorspace->flags |= PNG_COLORSPACE_INVALID;
+
+   pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */
+   pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */
+   pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */
+   if (is_ICC_signature(value) != 0)
+   {
+      /* So 'value' is at most 4 bytes and the following cast is safe */
+      png_icc_tag_name(message+pos, (png_uint_32)value);
+      pos += 6; /* total +8; less than the else clause */
+      message[pos++] = ':';
+      message[pos++] = ' ';
+   }
+#  ifdef PNG_WARNINGS_SUPPORTED
+   else
+      {
+         char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114*/
+
+         pos = png_safecat(message, (sizeof message), pos,
+             png_format_number(number, number+(sizeof number),
+             PNG_NUMBER_FORMAT_x, value));
+         pos = png_safecat(message, (sizeof message), pos, "h: "); /*+2 = 116*/
+      }
+#  endif
+   /* The 'reason' is an arbitrary message, allow +79 maximum 195 */
+   pos = png_safecat(message, (sizeof message), pos, reason);
+   PNG_UNUSED(pos)
+
+   /* This is recoverable, but make it unconditionally an app_error on write to
+    * avoid writing invalid ICC profiles into PNG files (i.e., we handle them
+    * on read, with a warning, but on write unless the app turns off
+    * application errors the PNG won't be written.)
+    */
+   png_chunk_report(png_ptr, message,
+       (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR);
+
+   return 0;
+}
+#endif /* sRGB || iCCP */
+
+#ifdef PNG_sRGB_SUPPORTED
+int /* PRIVATE */
+png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    int intent)
+{
+   /* sRGB sets known gamma, end points and (from the chunk) intent. */
+   /* IMPORTANT: these are not necessarily the values found in an ICC profile
+    * because ICC profiles store values adapted to a D50 environment; it is
+    * expected that the ICC profile mediaWhitePointTag will be D50; see the
+    * checks and code elsewhere to understand this better.
+    *
+    * These XYZ values, which are accurate to 5dp, produce rgb to gray
+    * coefficients of (6968,23435,2366), which are reduced (because they add up
+    * to 32769 not 32768) to (6968,23434,2366).  These are the values that
+    * libpng has traditionally used (and are the best values given the 15bit
+    * algorithm used by the rgb to gray code.)
+    */
+   static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */
+   {
+      /* color      X      Y      Z */
+      /* red   */ 41239, 21264,  1933,
+      /* green */ 35758, 71517, 11919,
+      /* blue  */ 18048,  7219, 95053
+   };
+
+   /* Do nothing if the colorspace is already invalidated. */
+   if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+      return 0;
+
+   /* Check the intent, then check for existing settings.  It is valid for the
+    * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must
+    * be consistent with the correct values.  If, however, this function is
+    * called below because an iCCP chunk matches sRGB then it is quite
+    * conceivable that an older app recorded incorrect gAMA and cHRM because of
+    * an incorrect calculation based on the values in the profile - this does
+    * *not* invalidate the profile (though it still produces an error, which can
+    * be ignored.)
+    */
+   if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST)
+      return png_icc_profile_error(png_ptr, colorspace, "sRGB",
+          (png_alloc_size_t)intent, "invalid sRGB rendering intent");
+
+   if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 &&
+       colorspace->rendering_intent != intent)
+      return png_icc_profile_error(png_ptr, colorspace, "sRGB",
+         (png_alloc_size_t)intent, "inconsistent rendering intents");
+
+   if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0)
+   {
+      png_benign_error(png_ptr, "duplicate sRGB information ignored");
+      return 0;
+   }
+
+   /* If the standard sRGB cHRM chunk does not match the one from the PNG file
+    * warn but overwrite the value with the correct one.
+    */
+   if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 &&
+       !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy,
+       100))
+      png_chunk_report(png_ptr, "cHRM chunk does not match sRGB",
+         PNG_CHUNK_ERROR);
+
+   /* This check is just done for the error reporting - the routine always
+    * returns true when the 'from' argument corresponds to sRGB (2).
+    */
+   (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE,
+       2/*from sRGB*/);
+
+   /* intent: bugs in GCC force 'int' to be used as the parameter type. */
+   colorspace->rendering_intent = (png_uint_16)intent;
+   colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT;
+
+   /* endpoints */
+   colorspace->end_points_xy = sRGB_xy;
+   colorspace->end_points_XYZ = sRGB_XYZ;
+   colorspace->flags |=
+      (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
+
+   /* gamma */
+   colorspace->gamma = PNG_GAMMA_sRGB_INVERSE;
+   colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA;
+
+   /* Finally record that we have an sRGB profile */
+   colorspace->flags |=
+      (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB);
+
+   return 1; /* set */
+}
+#endif /* sRGB */
+
+#ifdef PNG_iCCP_SUPPORTED
+/* Encoded value of D50 as an ICC XYZNumber.  From the ICC 2010 spec the value
+ * is XYZ(0.9642,1.0,0.8249), which scales to:
+ *
+ *    (63189.8112, 65536, 54060.6464)
+ */
+static const png_byte D50_nCIEXYZ[12] =
+   { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d };
+
+static int /* bool */
+icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length)
+{
+   if (profile_length < 132)
+      return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+          "too short");
+   return 1;
+}
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+int /* PRIVATE */
+png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length)
+{
+   if (!icc_check_length(png_ptr, colorspace, name, profile_length))
+      return 0;
+
+   /* This needs to be here because the 'normal' check is in
+    * png_decompress_chunk, yet this happens after the attempt to
+    * png_malloc_base the required data.  We only need this on read; on write
+    * the caller supplies the profile buffer so libpng doesn't allocate it.  See
+    * the call to icc_check_length below (the write case).
+    */
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      else if (png_ptr->user_chunk_malloc_max > 0 &&
+               png_ptr->user_chunk_malloc_max < profile_length)
+         return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+             "exceeds application limits");
+#  elif PNG_USER_CHUNK_MALLOC_MAX > 0
+      else if (PNG_USER_CHUNK_MALLOC_MAX < profile_length)
+         return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+             "exceeds libpng limits");
+#  else /* !SET_USER_LIMITS */
+      /* This will get compiled out on all 32-bit and better systems. */
+      else if (PNG_SIZE_MAX < profile_length)
+         return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+             "exceeds system limits");
+#  endif /* !SET_USER_LIMITS */
+
+   return 1;
+}
+#endif /* READ_iCCP */
+
+int /* PRIVATE */
+png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length,
+    png_const_bytep profile/* first 132 bytes only */, int color_type)
+{
+   png_uint_32 temp;
+
+   /* Length check; this cannot be ignored in this code because profile_length
+    * is used later to check the tag table, so even if the profile seems over
+    * long profile_length from the caller must be correct.  The caller can fix
+    * this up on read or write by just passing in the profile header length.
+    */
+   temp = png_get_uint_32(profile);
+   if (temp != profile_length)
+      return png_icc_profile_error(png_ptr, colorspace, name, temp,
+          "length does not match profile");
+
+   temp = (png_uint_32) (*(profile+8));
+   if (temp > 3 && (profile_length & 3))
+      return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+          "invalid length");
+
+   temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */
+   if (temp > 357913930 || /* (2^32-4-132)/12: maximum possible tag count */
+      profile_length < 132+12*temp) /* truncated tag table */
+      return png_icc_profile_error(png_ptr, colorspace, name, temp,
+          "tag count too large");
+
+   /* The 'intent' must be valid or we can't store it, ICC limits the intent to
+    * 16 bits.
+    */
+   temp = png_get_uint_32(profile+64);
+   if (temp >= 0xffff) /* The ICC limit */
+      return png_icc_profile_error(png_ptr, colorspace, name, temp,
+          "invalid rendering intent");
+
+   /* This is just a warning because the profile may be valid in future
+    * versions.
+    */
+   if (temp >= PNG_sRGB_INTENT_LAST)
+      (void)png_icc_profile_error(png_ptr, NULL, name, temp,
+          "intent outside defined range");
+
+   /* At this point the tag table can't be checked because it hasn't necessarily
+    * been loaded; however, various header fields can be checked.  These checks
+    * are for values permitted by the PNG spec in an ICC profile; the PNG spec
+    * restricts the profiles that can be passed in an iCCP chunk (they must be
+    * appropriate to processing PNG data!)
+    */
+
+   /* Data checks (could be skipped).  These checks must be independent of the
+    * version number; however, the version number doesn't accommodate changes in
+    * the header fields (just the known tags and the interpretation of the
+    * data.)
+    */
+   temp = png_get_uint_32(profile+36); /* signature 'ascp' */
+   if (temp != 0x61637370)
+      return png_icc_profile_error(png_ptr, colorspace, name, temp,
+          "invalid signature");
+
+   /* Currently the PCS illuminant/adopted white point (the computational
+    * white point) are required to be D50,
+    * however the profile contains a record of the illuminant so perhaps ICC
+    * expects to be able to change this in the future (despite the rationale in
+    * the introduction for using a fixed PCS adopted white.)  Consequently the
+    * following is just a warning.
+    */
+   if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0)
+      (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/,
+          "PCS illuminant is not D50");
+
+   /* The PNG spec requires this:
+    * "If the iCCP chunk is present, the image samples conform to the colour
+    * space represented by the embedded ICC profile as defined by the
+    * International Color Consortium [ICC]. The colour space of the ICC profile
+    * shall be an RGB colour space for colour images (PNG colour types 2, 3, and
+    * 6), or a greyscale colour space for greyscale images (PNG colour types 0
+    * and 4)."
+    *
+    * This checking code ensures the embedded profile (on either read or write)
+    * conforms to the specification requirements.  Notice that an ICC 'gray'
+    * color-space profile contains the information to transform the monochrome
+    * data to XYZ or L*a*b (according to which PCS the profile uses) and this
+    * should be used in preference to the standard libpng K channel replication
+    * into R, G and B channels.
+    *
+    * Previously it was suggested that an RGB profile on grayscale data could be
+    * handled.  However it it is clear that using an RGB profile in this context
+    * must be an error - there is no specification of what it means.  Thus it is
+    * almost certainly more correct to ignore the profile.
+    */
+   temp = png_get_uint_32(profile+16); /* data colour space field */
+   switch (temp)
+   {
+      case 0x52474220: /* 'RGB ' */
+         if ((color_type & PNG_COLOR_MASK_COLOR) == 0)
+            return png_icc_profile_error(png_ptr, colorspace, name, temp,
+                "RGB color space not permitted on grayscale PNG");
+         break;
+
+      case 0x47524159: /* 'GRAY' */
+         if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+            return png_icc_profile_error(png_ptr, colorspace, name, temp,
+                "Gray color space not permitted on RGB PNG");
+         break;
+
+      default:
+         return png_icc_profile_error(png_ptr, colorspace, name, temp,
+             "invalid ICC profile color space");
+   }
+
+   /* It is up to the application to check that the profile class matches the
+    * application requirements; the spec provides no guidance, but it's pretty
+    * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer
+    * ('prtr') or 'spac' (for generic color spaces).  Issue a warning in these
+    * cases.  Issue an error for device link or abstract profiles - these don't
+    * contain the records necessary to transform the color-space to anything
+    * other than the target device (and not even that for an abstract profile).
+    * Profiles of these classes may not be embedded in images.
+    */
+   temp = png_get_uint_32(profile+12); /* profile/device class */
+   switch (temp)
+   {
+      case 0x73636e72: /* 'scnr' */
+      case 0x6d6e7472: /* 'mntr' */
+      case 0x70727472: /* 'prtr' */
+      case 0x73706163: /* 'spac' */
+         /* All supported */
+         break;
+
+      case 0x61627374: /* 'abst' */
+         /* May not be embedded in an image */
+         return png_icc_profile_error(png_ptr, colorspace, name, temp,
+             "invalid embedded Abstract ICC profile");
+
+      case 0x6c696e6b: /* 'link' */
+         /* DeviceLink profiles cannot be interpreted in a non-device specific
+          * fashion, if an app uses the AToB0Tag in the profile the results are
+          * undefined unless the result is sent to the intended device,
+          * therefore a DeviceLink profile should not be found embedded in a
+          * PNG.
+          */
+         return png_icc_profile_error(png_ptr, colorspace, name, temp,
+             "unexpected DeviceLink ICC profile class");
+
+      case 0x6e6d636c: /* 'nmcl' */
+         /* A NamedColor profile is also device specific, however it doesn't
+          * contain an AToB0 tag that is open to misinterpretation.  Almost
+          * certainly it will fail the tests below.
+          */
+         (void)png_icc_profile_error(png_ptr, NULL, name, temp,
+             "unexpected NamedColor ICC profile class");
+         break;
+
+      default:
+         /* To allow for future enhancements to the profile accept unrecognized
+          * profile classes with a warning, these then hit the test below on the
+          * tag content to ensure they are backward compatible with one of the
+          * understood profiles.
+          */
+         (void)png_icc_profile_error(png_ptr, NULL, name, temp,
+             "unrecognized ICC profile class");
+         break;
+   }
+
+   /* For any profile other than a device link one the PCS must be encoded
+    * either in XYZ or Lab.
+    */
+   temp = png_get_uint_32(profile+20);
+   switch (temp)
+   {
+      case 0x58595a20: /* 'XYZ ' */
+      case 0x4c616220: /* 'Lab ' */
+         break;
+
+      default:
+         return png_icc_profile_error(png_ptr, colorspace, name, temp,
+             "unexpected ICC PCS encoding");
+   }
+
+   return 1;
+}
+
+int /* PRIVATE */
+png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length,
+    png_const_bytep profile /* header plus whole tag table */)
+{
+   png_uint_32 tag_count = png_get_uint_32(profile+128);
+   png_uint_32 itag;
+   png_const_bytep tag = profile+132; /* The first tag */
+
+   /* First scan all the tags in the table and add bits to the icc_info value
+    * (temporarily in 'tags').
+    */
+   for (itag=0; itag < tag_count; ++itag, tag += 12)
+   {
+      png_uint_32 tag_id = png_get_uint_32(tag+0);
+      png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */
+      png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */
+
+      /* The ICC specification does not exclude zero length tags, therefore the
+       * start might actually be anywhere if there is no data, but this would be
+       * a clear abuse of the intent of the standard so the start is checked for
+       * being in range.  All defined tag types have an 8 byte header - a 4 byte
+       * type signature then 0.
+       */
+
+      /* This is a hard error; potentially it can cause read outside the
+       * profile.
+       */
+      if (tag_start > profile_length || tag_length > profile_length - tag_start)
+         return png_icc_profile_error(png_ptr, colorspace, name, tag_id,
+             "ICC profile tag outside profile");
+
+      if ((tag_start & 3) != 0)
+      {
+         /* CNHP730S.icc shipped with Microsoft Windows 64 violates this; it is
+          * only a warning here because libpng does not care about the
+          * alignment.
+          */
+         (void)png_icc_profile_error(png_ptr, NULL, name, tag_id,
+             "ICC profile tag start not a multiple of 4");
+      }
+   }
+
+   return 1; /* success, maybe with warnings */
+}
+
+#ifdef PNG_sRGB_SUPPORTED
+#if PNG_sRGB_PROFILE_CHECKS >= 0
+/* Information about the known ICC sRGB profiles */
+static const struct
+{
+   png_uint_32 adler, crc, length;
+   png_uint_32 md5[4];
+   png_byte    have_md5;
+   png_byte    is_broken;
+   png_uint_16 intent;
+
+#  define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0)
+#  define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\
+      { adler, crc, length, md5, broke, intent },
+
+} png_sRGB_checks[] =
+{
+   /* This data comes from contrib/tools/checksum-icc run on downloads of
+    * all four ICC sRGB profiles from www.color.org.
+    */
+   /* adler32, crc32, MD5[4], intent, date, length, file-name */
+   PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9,
+       PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0,
+       "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc")
+
+   /* ICC sRGB v2 perceptual no black-compensation: */
+   PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21,
+       PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0,
+       "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc")
+
+   PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae,
+       PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0,
+       "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc")
+
+   /* ICC sRGB v4 perceptual */
+   PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812,
+       PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0,
+       "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc")
+
+   /* The following profiles have no known MD5 checksum. If there is a match
+    * on the (empty) MD5 the other fields are used to attempt a match and
+    * a warning is produced.  The first two of these profiles have a 'cprt' tag
+    * which suggests that they were also made by Hewlett Packard.
+    */
+   PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce,
+       PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0,
+       "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc")
+
+   /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not
+    * match the D50 PCS illuminant in the header (it is in fact the D65 values,
+    * so the white point is recorded as the un-adapted value.)  The profiles
+    * below only differ in one byte - the intent - and are basically the same as
+    * the previous profile except for the mediaWhitePointTag error and a missing
+    * chromaticAdaptationTag.
+    */
+   PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552,
+       PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/,
+       "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual")
+
+   PNG_ICC_CHECKSUM(0x0398f3fc, 0xf29e526d,
+       PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/,
+       "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative")
+};
+
+static int
+png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
+    png_const_bytep profile, uLong adler)
+{
+   /* The quick check is to verify just the MD5 signature and trust the
+    * rest of the data.  Because the profile has already been verified for
+    * correctness this is safe.  png_colorspace_set_sRGB will check the 'intent'
+    * field too, so if the profile has been edited with an intent not defined
+    * by sRGB (but maybe defined by a later ICC specification) the read of
+    * the profile will fail at that point.
+    */
+
+   png_uint_32 length = 0;
+   png_uint_32 intent = 0x10000; /* invalid */
+#if PNG_sRGB_PROFILE_CHECKS > 1
+   uLong crc = 0; /* the value for 0 length data */
+#endif
+   unsigned int i;
+
+#ifdef PNG_SET_OPTION_SUPPORTED
+   /* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */
+   if (((png_ptr->options >> PNG_SKIP_sRGB_CHECK_PROFILE) & 3) ==
+               PNG_OPTION_ON)
+      return 0;
+#endif
+
+   for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i)
+   {
+      if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] &&
+         png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] &&
+         png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] &&
+         png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3])
+      {
+         /* This may be one of the old HP profiles without an MD5, in that
+          * case we can only use the length and Adler32 (note that these
+          * are not used by default if there is an MD5!)
+          */
+#        if PNG_sRGB_PROFILE_CHECKS == 0
+            if (png_sRGB_checks[i].have_md5 != 0)
+               return 1+png_sRGB_checks[i].is_broken;
+#        endif
+
+         /* Profile is unsigned or more checks have been configured in. */
+         if (length == 0)
+         {
+            length = png_get_uint_32(profile);
+            intent = png_get_uint_32(profile+64);
+         }
+
+         /* Length *and* intent must match */
+         if (length == (png_uint_32) png_sRGB_checks[i].length &&
+            intent == (png_uint_32) png_sRGB_checks[i].intent)
+         {
+            /* Now calculate the adler32 if not done already. */
+            if (adler == 0)
+            {
+               adler = adler32(0, NULL, 0);
+               adler = adler32(adler, profile, length);
+            }
+
+            if (adler == png_sRGB_checks[i].adler)
+            {
+               /* These basic checks suggest that the data has not been
+                * modified, but if the check level is more than 1 perform
+                * our own crc32 checksum on the data.
+                */
+#              if PNG_sRGB_PROFILE_CHECKS > 1
+                  if (crc == 0)
+                  {
+                     crc = crc32(0, NULL, 0);
+                     crc = crc32(crc, profile, length);
+                  }
+
+                  /* So this check must pass for the 'return' below to happen.
+                   */
+                  if (crc == png_sRGB_checks[i].crc)
+#              endif
+               {
+                  if (png_sRGB_checks[i].is_broken != 0)
+                  {
+                     /* These profiles are known to have bad data that may cause
+                      * problems if they are used, therefore attempt to
+                      * discourage their use, skip the 'have_md5' warning below,
+                      * which is made irrelevant by this error.
+                      */
+                     png_chunk_report(png_ptr, "known incorrect sRGB profile",
+                         PNG_CHUNK_ERROR);
+                  }
+
+                  /* Warn that this being done; this isn't even an error since
+                   * the profile is perfectly valid, but it would be nice if
+                   * people used the up-to-date ones.
+                   */
+                  else if (png_sRGB_checks[i].have_md5 == 0)
+                  {
+                     png_chunk_report(png_ptr,
+                         "out-of-date sRGB profile with no signature",
+                         PNG_CHUNK_WARNING);
+                  }
+
+                  return 1+png_sRGB_checks[i].is_broken;
+               }
+            }
+
+# if PNG_sRGB_PROFILE_CHECKS > 0
+         /* The signature matched, but the profile had been changed in some
+          * way.  This probably indicates a data error or uninformed hacking.
+          * Fall through to "no match".
+          */
+         png_chunk_report(png_ptr,
+             "Not recognizing known sRGB profile that has been edited",
+             PNG_CHUNK_WARNING);
+         break;
+# endif
+         }
+      }
+   }
+
+   return 0; /* no match */
+}
+
+void /* PRIVATE */
+png_icc_set_sRGB(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, png_const_bytep profile, uLong adler)
+{
+   /* Is this profile one of the known ICC sRGB profiles?  If it is, just set
+    * the sRGB information.
+    */
+   if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler) != 0)
+      (void)png_colorspace_set_sRGB(png_ptr, colorspace,
+         (int)/*already checked*/png_get_uint_32(profile+64));
+}
+#endif /* PNG_sRGB_PROFILE_CHECKS >= 0 */
+#endif /* sRGB */
+
+int /* PRIVATE */
+png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length, png_const_bytep profile,
+    int color_type)
+{
+   if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+      return 0;
+
+   if (icc_check_length(png_ptr, colorspace, name, profile_length) != 0 &&
+       png_icc_check_header(png_ptr, colorspace, name, profile_length, profile,
+           color_type) != 0 &&
+       png_icc_check_tag_table(png_ptr, colorspace, name, profile_length,
+           profile) != 0)
+   {
+#     if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
+         /* If no sRGB support, don't try storing sRGB information */
+         png_icc_set_sRGB(png_ptr, colorspace, profile, 0);
+#     endif
+      return 1;
+   }
+
+   /* Failure case */
+   return 0;
+}
+#endif /* iCCP */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+void /* PRIVATE */
+png_colorspace_set_rgb_coefficients(png_structrp png_ptr)
+{
+   /* Set the rgb_to_gray coefficients from the colorspace. */
+   if (png_ptr->rgb_to_gray_coefficients_set == 0 &&
+      (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      /* png_set_background has not been called, get the coefficients from the Y
+       * values of the colorspace colorants.
+       */
+      png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y;
+      png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y;
+      png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y;
+      png_fixed_point total = r+g+b;
+
+      if (total > 0 &&
+         r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 &&
+         g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 &&
+         b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 &&
+         r+g+b <= 32769)
+      {
+         /* We allow 0 coefficients here.  r+g+b may be 32769 if two or
+          * all of the coefficients were rounded up.  Handle this by
+          * reducing the *largest* coefficient by 1; this matches the
+          * approach used for the default coefficients in pngrtran.c
+          */
+         int add = 0;
+
+         if (r+g+b > 32768)
+            add = -1;
+         else if (r+g+b < 32768)
+            add = 1;
+
+         if (add != 0)
+         {
+            if (g >= r && g >= b)
+               g += add;
+            else if (r >= g && r >= b)
+               r += add;
+            else
+               b += add;
+         }
+
+         /* Check for an internal error. */
+         if (r+g+b != 32768)
+            png_error(png_ptr,
+                "internal error handling cHRM coefficients");
+
+         else
+         {
+            png_ptr->rgb_to_gray_red_coeff   = (png_uint_16)r;
+            png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
+         }
+      }
+
+      /* This is a png_error at present even though it could be ignored -
+       * it should never happen, but it is important that if it does, the
+       * bug is fixed.
+       */
+      else
+         png_error(png_ptr, "internal error handling cHRM->XYZ");
+   }
+}
+#endif /* READ_RGB_TO_GRAY */
+
+#endif /* COLORSPACE */
+
+#ifdef __GNUC__
+/* This exists solely to work round a warning from GNU C. */
+static int /* PRIVATE */
+png_gt(size_t a, size_t b)
+{
+   return a > b;
+}
+#else
+#   define png_gt(a,b) ((a) > (b))
+#endif
+
+void /* PRIVATE */
+png_check_IHDR(png_const_structrp png_ptr,
+    png_uint_32 width, png_uint_32 height, int bit_depth,
+    int color_type, int interlace_type, int compression_type,
+    int filter_type)
+{
+   int error = 0;
+
+   /* Check for width and height valid values */
+   if (width == 0)
+   {
+      png_warning(png_ptr, "Image width is zero in IHDR");
+      error = 1;
+   }
+
+   if (width > PNG_UINT_31_MAX)
+   {
+      png_warning(png_ptr, "Invalid image width in IHDR");
+      error = 1;
+   }
+
+   if (png_gt(((width + 7) & (~7U)),
+       ((PNG_SIZE_MAX
+           - 48        /* big_row_buf hack */
+           - 1)        /* filter byte */
+           / 8)        /* 8-byte RGBA pixels */
+           - 1))       /* extra max_pixel_depth pad */
+   {
+      /* The size of the row must be within the limits of this architecture.
+       * Because the read code can perform arbitrary transformations the
+       * maximum size is checked here.  Because the code in png_read_start_row
+       * adds extra space "for safety's sake" in several places a conservative
+       * limit is used here.
+       *
+       * NOTE: it would be far better to check the size that is actually used,
+       * but the effect in the real world is minor and the changes are more
+       * extensive, therefore much more dangerous and much more difficult to
+       * write in a way that avoids compiler warnings.
+       */
+      png_warning(png_ptr, "Image width is too large for this architecture");
+      error = 1;
+   }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (width > png_ptr->user_width_max)
+#else
+   if (width > PNG_USER_WIDTH_MAX)
+#endif
+   {
+      png_warning(png_ptr, "Image width exceeds user limit in IHDR");
+      error = 1;
+   }
+
+   if (height == 0)
+   {
+      png_warning(png_ptr, "Image height is zero in IHDR");
+      error = 1;
+   }
+
+   if (height > PNG_UINT_31_MAX)
+   {
+      png_warning(png_ptr, "Invalid image height in IHDR");
+      error = 1;
+   }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (height > png_ptr->user_height_max)
+#else
+   if (height > PNG_USER_HEIGHT_MAX)
+#endif
+   {
+      png_warning(png_ptr, "Image height exceeds user limit in IHDR");
+      error = 1;
+   }
+
+   /* Check other values */
+   if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
+       bit_depth != 8 && bit_depth != 16)
+   {
+      png_warning(png_ptr, "Invalid bit depth in IHDR");
+      error = 1;
+   }
+
+   if (color_type < 0 || color_type == 1 ||
+       color_type == 5 || color_type > 6)
+   {
+      png_warning(png_ptr, "Invalid color type in IHDR");
+      error = 1;
+   }
+
+   if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
+       ((color_type == PNG_COLOR_TYPE_RGB ||
+         color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
+         color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
+   {
+      png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
+      error = 1;
+   }
+
+   if (interlace_type >= PNG_INTERLACE_LAST)
+   {
+      png_warning(png_ptr, "Unknown interlace method in IHDR");
+      error = 1;
+   }
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Unknown compression method in IHDR");
+      error = 1;
+   }
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   /* Accept filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not read a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 &&
+       png_ptr->mng_features_permitted != 0)
+      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
+
+   if (filter_type != PNG_FILTER_TYPE_BASE)
+   {
+      if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+          (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
+          ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
+          (color_type == PNG_COLOR_TYPE_RGB ||
+          color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+      {
+         png_warning(png_ptr, "Unknown filter method in IHDR");
+         error = 1;
+      }
+
+      if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0)
+      {
+         png_warning(png_ptr, "Invalid filter method in IHDR");
+         error = 1;
+      }
+   }
+
+#else
+   if (filter_type != PNG_FILTER_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Unknown filter method in IHDR");
+      error = 1;
+   }
+#endif
+
+   if (error == 1)
+      png_error(png_ptr, "Invalid IHDR data");
+}
+
+#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
+/* ASCII to fp functions */
+/* Check an ASCII formatted floating point value, see the more detailed
+ * comments in pngpriv.h
+ */
+/* The following is used internally to preserve the sticky flags */
+#define png_fp_add(state, flags) ((state) |= (flags))
+#define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY))
+
+int /* PRIVATE */
+png_check_fp_number(png_const_charp string, size_t size, int *statep,
+    png_size_tp whereami)
+{
+   int state = *statep;
+   size_t i = *whereami;
+
+   while (i < size)
+   {
+      int type;
+      /* First find the type of the next character */
+      switch (string[i])
+      {
+      case 43:  type = PNG_FP_SAW_SIGN;                   break;
+      case 45:  type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break;
+      case 46:  type = PNG_FP_SAW_DOT;                    break;
+      case 48:  type = PNG_FP_SAW_DIGIT;                  break;
+      case 49: case 50: case 51: case 52:
+      case 53: case 54: case 55: case 56:
+      case 57:  type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break;
+      case 69:
+      case 101: type = PNG_FP_SAW_E;                      break;
+      default:  goto PNG_FP_End;
+      }
+
+      /* Now deal with this type according to the current
+       * state, the type is arranged to not overlap the
+       * bits of the PNG_FP_STATE.
+       */
+      switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY))
+      {
+      case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
+         if ((state & PNG_FP_SAW_ANY) != 0)
+            goto PNG_FP_End; /* not a part of the number */
+
+         png_fp_add(state, type);
+         break;
+
+      case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
+         /* Ok as trailer, ok as lead of fraction. */
+         if ((state & PNG_FP_SAW_DOT) != 0) /* two dots */
+            goto PNG_FP_End;
+
+         else if ((state & PNG_FP_SAW_DIGIT) != 0) /* trailing dot? */
+            png_fp_add(state, type);
+
+         else
+            png_fp_set(state, PNG_FP_FRACTION | type);
+
+         break;
+
+      case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
+         if ((state & PNG_FP_SAW_DOT) != 0) /* delayed fraction */
+            png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);
+
+         png_fp_add(state, type | PNG_FP_WAS_VALID);
+
+         break;
+
+      case PNG_FP_INTEGER + PNG_FP_SAW_E:
+         if ((state & PNG_FP_SAW_DIGIT) == 0)
+            goto PNG_FP_End;
+
+         png_fp_set(state, PNG_FP_EXPONENT);
+
+         break;
+
+   /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN:
+         goto PNG_FP_End; ** no sign in fraction */
+
+   /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT:
+         goto PNG_FP_End; ** Because SAW_DOT is always set */
+
+      case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT:
+         png_fp_add(state, type | PNG_FP_WAS_VALID);
+         break;
+
+      case PNG_FP_FRACTION + PNG_FP_SAW_E:
+         /* This is correct because the trailing '.' on an
+          * integer is handled above - so we can only get here
+          * with the sequence ".E" (with no preceding digits).
+          */
+         if ((state & PNG_FP_SAW_DIGIT) == 0)
+            goto PNG_FP_End;
+
+         png_fp_set(state, PNG_FP_EXPONENT);
+
+         break;
+
+      case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
+         if ((state & PNG_FP_SAW_ANY) != 0)
+            goto PNG_FP_End; /* not a part of the number */
+
+         png_fp_add(state, PNG_FP_SAW_SIGN);
+
+         break;
+
+   /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT:
+         goto PNG_FP_End; */
+
+      case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT:
+         png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID);
+
+         break;
+
+   /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E:
+         goto PNG_FP_End; */
+
+      default: goto PNG_FP_End; /* I.e. break 2 */
+      }
+
+      /* The character seems ok, continue. */
+      ++i;
+   }
+
+PNG_FP_End:
+   /* Here at the end, update the state and return the correct
+    * return code.
+    */
+   *statep = state;
+   *whereami = i;
+
+   return (state & PNG_FP_SAW_DIGIT) != 0;
+}
+
+
+/* The same but for a complete string. */
+int
+png_check_fp_string(png_const_charp string, size_t size)
+{
+   int        state=0;
+   size_t char_index=0;
+
+   if (png_check_fp_number(string, size, &state, &char_index) != 0 &&
+      (char_index == size || string[char_index] == 0))
+      return state /* must be non-zero - see above */;
+
+   return 0; /* i.e. fail */
+}
+#endif /* pCAL || sCAL */
+
+#ifdef PNG_sCAL_SUPPORTED
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+/* Utility used below - a simple accurate power of ten from an integral
+ * exponent.
+ */
+static double
+png_pow10(int power)
+{
+   int recip = 0;
+   double d = 1;
+
+   /* Handle negative exponent with a reciprocal at the end because
+    * 10 is exact whereas .1 is inexact in base 2
+    */
+   if (power < 0)
+   {
+      if (power < DBL_MIN_10_EXP) return 0;
+      recip = 1; power = -power;
+   }
+
+   if (power > 0)
+   {
+      /* Decompose power bitwise. */
+      double mult = 10;
+      do
+      {
+         if (power & 1) d *= mult;
+         mult *= mult;
+         power >>= 1;
+      }
+      while (power > 0);
+
+      if (recip != 0) d = 1/d;
+   }
+   /* else power is 0 and d is 1 */
+
+   return d;
+}
+
+/* Function to format a floating point value in ASCII with a given
+ * precision.
+ */
+#if GCC_STRICT_OVERFLOW
+#pragma GCC diagnostic push
+/* The problem arises below with exp_b10, which can never overflow because it
+ * comes, originally, from frexp and is therefore limited to a range which is
+ * typically +/-710 (log2(DBL_MAX)/log2(DBL_MIN)).
+ */
+#pragma GCC diagnostic warning "-Wstrict-overflow=2"
+#endif /* GCC_STRICT_OVERFLOW */
+void /* PRIVATE */
+png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, size_t size,
+    double fp, unsigned int precision)
+{
+   /* We use standard functions from math.h, but not printf because
+    * that would require stdio.  The caller must supply a buffer of
+    * sufficient size or we will png_error.  The tests on size and
+    * the space in ascii[] consumed are indicated below.
+    */
+   if (precision < 1)
+      precision = DBL_DIG;
+
+   /* Enforce the limit of the implementation precision too. */
+   if (precision > DBL_DIG+1)
+      precision = DBL_DIG+1;
+
+   /* Basic sanity checks */
+   if (size >= precision+5) /* See the requirements below. */
+   {
+      if (fp < 0)
+      {
+         fp = -fp;
+         *ascii++ = 45; /* '-'  PLUS 1 TOTAL 1 */
+         --size;
+      }
+
+      if (fp >= DBL_MIN && fp <= DBL_MAX)
+      {
+         int exp_b10;   /* A base 10 exponent */
+         double base;   /* 10^exp_b10 */
+
+         /* First extract a base 10 exponent of the number,
+          * the calculation below rounds down when converting
+          * from base 2 to base 10 (multiply by log10(2) -
+          * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to
+          * be increased.  Note that the arithmetic shift
+          * performs a floor() unlike C arithmetic - using a
+          * C multiply would break the following for negative
+          * exponents.
+          */
+         (void)frexp(fp, &exp_b10); /* exponent to base 2 */
+
+         exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */
+
+         /* Avoid underflow here. */
+         base = png_pow10(exp_b10); /* May underflow */
+
+         while (base < DBL_MIN || base < fp)
+         {
+            /* And this may overflow. */
+            double test = png_pow10(exp_b10+1);
+
+            if (test <= DBL_MAX)
+            {
+               ++exp_b10; base = test;
+            }
+
+            else
+               break;
+         }
+
+         /* Normalize fp and correct exp_b10, after this fp is in the
+          * range [.1,1) and exp_b10 is both the exponent and the digit
+          * *before* which the decimal point should be inserted
+          * (starting with 0 for the first digit).  Note that this
+          * works even if 10^exp_b10 is out of range because of the
+          * test on DBL_MAX above.
+          */
+         fp /= base;
+         while (fp >= 1)
+         {
+            fp /= 10; ++exp_b10;
+         }
+
+         /* Because of the code above fp may, at this point, be
+          * less than .1, this is ok because the code below can
+          * handle the leading zeros this generates, so no attempt
+          * is made to correct that here.
+          */
+
+         {
+            unsigned int czero, clead, cdigits;
+            char exponent[10];
+
+            /* Allow up to two leading zeros - this will not lengthen
+             * the number compared to using E-n.
+             */
+            if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */
+            {
+               czero = 0U-exp_b10; /* PLUS 2 digits: TOTAL 3 */
+               exp_b10 = 0;      /* Dot added below before first output. */
+            }
+            else
+               czero = 0;    /* No zeros to add */
+
+            /* Generate the digit list, stripping trailing zeros and
+             * inserting a '.' before a digit if the exponent is 0.
+             */
+            clead = czero; /* Count of leading zeros */
+            cdigits = 0;   /* Count of digits in list. */
+
+            do
+            {
+               double d;
+
+               fp *= 10;
+               /* Use modf here, not floor and subtract, so that
+                * the separation is done in one step.  At the end
+                * of the loop don't break the number into parts so
+                * that the final digit is rounded.
+                */
+               if (cdigits+czero+1 < precision+clead)
+                  fp = modf(fp, &d);
+
+               else
+               {
+                  d = floor(fp + .5);
+
+                  if (d > 9)
+                  {
+                     /* Rounding up to 10, handle that here. */
+                     if (czero > 0)
+                     {
+                        --czero; d = 1;
+                        if (cdigits == 0) --clead;
+                     }
+                     else
+                     {
+                        while (cdigits > 0 && d > 9)
+                        {
+                           int ch = *--ascii;
+
+                           if (exp_b10 != (-1))
+                              ++exp_b10;
+
+                           else if (ch == 46)
+                           {
+                              ch = *--ascii; ++size;
+                              /* Advance exp_b10 to '1', so that the
+                               * decimal point happens after the
+                               * previous digit.
+                               */
+                              exp_b10 = 1;
+                           }
+
+                           --cdigits;
+                           d = ch - 47;  /* I.e. 1+(ch-48) */
+                        }
+
+                        /* Did we reach the beginning? If so adjust the
+                         * exponent but take into account the leading
+                         * decimal point.
+                         */
+                        if (d > 9)  /* cdigits == 0 */
+                        {
+                           if (exp_b10 == (-1))
+                           {
+                              /* Leading decimal point (plus zeros?), if
+                               * we lose the decimal point here it must
+                               * be reentered below.
+                               */
+                              int ch = *--ascii;
+
+                              if (ch == 46)
+                              {
+                                 ++size; exp_b10 = 1;
+                              }
+
+                              /* Else lost a leading zero, so 'exp_b10' is
+                               * still ok at (-1)
+                               */
+                           }
+                           else
+                              ++exp_b10;
+
+                           /* In all cases we output a '1' */
+                           d = 1;
+                        }
+                     }
+                  }
+                  fp = 0; /* Guarantees termination below. */
+               }
+
+               if (d == 0)
+               {
+                  ++czero;
+                  if (cdigits == 0) ++clead;
+               }
+               else
+               {
+                  /* Included embedded zeros in the digit count. */
+                  cdigits += czero - clead;
+                  clead = 0;
+
+                  while (czero > 0)
+                  {
+                     /* exp_b10 == (-1) means we just output the decimal
+                      * place - after the DP don't adjust 'exp_b10' any
+                      * more!
+                      */
+                     if (exp_b10 != (-1))
+                     {
+                        if (exp_b10 == 0)
+                        {
+                           *ascii++ = 46; --size;
+                        }
+                        /* PLUS 1: TOTAL 4 */
+                        --exp_b10;
+                     }
+                     *ascii++ = 48; --czero;
+                  }
+
+                  if (exp_b10 != (-1))
+                  {
+                     if (exp_b10 == 0)
+                     {
+                        *ascii++ = 46; --size; /* counted above */
+                     }
+
+                     --exp_b10;
+                  }
+                  *ascii++ = (char)(48 + (int)d); ++cdigits;
+               }
+            }
+            while (cdigits+czero < precision+clead && fp > DBL_MIN);
+
+            /* The total output count (max) is now 4+precision */
+
+            /* Check for an exponent, if we don't need one we are
+             * done and just need to terminate the string.  At this
+             * point, exp_b10==(-1) is effectively a flag: it got
+             * to '-1' because of the decrement, after outputting
+             * the decimal point above. (The exponent required is
+             * *not* -1.)
+             */
+            if (exp_b10 >= (-1) && exp_b10 <= 2)
+            {
+               /* The following only happens if we didn't output the
+                * leading zeros above for negative exponent, so this
+                * doesn't add to the digit requirement.  Note that the
+                * two zeros here can only be output if the two leading
+                * zeros were *not* output, so this doesn't increase
+                * the output count.
+                */
+               while (exp_b10-- > 0) *ascii++ = 48;
+
+               *ascii = 0;
+
+               /* Total buffer requirement (including the '\0') is
+                * 5+precision - see check at the start.
+                */
+               return;
+            }
+
+            /* Here if an exponent is required, adjust size for
+             * the digits we output but did not count.  The total
+             * digit output here so far is at most 1+precision - no
+             * decimal point and no leading or trailing zeros have
+             * been output.
+             */
+            size -= cdigits;
+
+            *ascii++ = 69; --size;    /* 'E': PLUS 1 TOTAL 2+precision */
+
+            /* The following use of an unsigned temporary avoids ambiguities in
+             * the signed arithmetic on exp_b10 and permits GCC at least to do
+             * better optimization.
+             */
+            {
+               unsigned int uexp_b10;
+
+               if (exp_b10 < 0)
+               {
+                  *ascii++ = 45; --size; /* '-': PLUS 1 TOTAL 3+precision */
+                  uexp_b10 = 0U-exp_b10;
+               }
+
+               else
+                  uexp_b10 = 0U+exp_b10;
+
+               cdigits = 0;
+
+               while (uexp_b10 > 0)
+               {
+                  exponent[cdigits++] = (char)(48 + uexp_b10 % 10);
+                  uexp_b10 /= 10;
+               }
+            }
+
+            /* Need another size check here for the exponent digits, so
+             * this need not be considered above.
+             */
+            if (size > cdigits)
+            {
+               while (cdigits > 0) *ascii++ = exponent[--cdigits];
+
+               *ascii = 0;
+
+               return;
+            }
+         }
+      }
+      else if (!(fp >= DBL_MIN))
+      {
+         *ascii++ = 48; /* '0' */
+         *ascii = 0;
+         return;
+      }
+      else
+      {
+         *ascii++ = 105; /* 'i' */
+         *ascii++ = 110; /* 'n' */
+         *ascii++ = 102; /* 'f' */
+         *ascii = 0;
+         return;
+      }
+   }
+
+   /* Here on buffer too small. */
+   png_error(png_ptr, "ASCII conversion buffer too small");
+}
+#if GCC_STRICT_OVERFLOW
+#pragma GCC diagnostic pop
+#endif /* GCC_STRICT_OVERFLOW */
+
+#  endif /* FLOATING_POINT */
+
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+/* Function to format a fixed point value in ASCII.
+ */
+void /* PRIVATE */
+png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
+    size_t size, png_fixed_point fp)
+{
+   /* Require space for 10 decimal digits, a decimal point, a minus sign and a
+    * trailing \0, 13 characters:
+    */
+   if (size > 12)
+   {
+      png_uint_32 num;
+
+      /* Avoid overflow here on the minimum integer. */
+      if (fp < 0)
+      {
+         *ascii++ = 45; num = (png_uint_32)(-fp);
+      }
+      else
+         num = (png_uint_32)fp;
+
+      if (num <= 0x80000000) /* else overflowed */
+      {
+         unsigned int ndigits = 0, first = 16 /* flag value */;
+         char digits[10];
+
+         while (num)
+         {
+            /* Split the low digit off num: */
+            unsigned int tmp = num/10;
+            num -= tmp*10;
+            digits[ndigits++] = (char)(48 + num);
+            /* Record the first non-zero digit, note that this is a number
+             * starting at 1, it's not actually the array index.
+             */
+            if (first == 16 && num > 0)
+               first = ndigits;
+            num = tmp;
+         }
+
+         if (ndigits > 0)
+         {
+            while (ndigits > 5) *ascii++ = digits[--ndigits];
+            /* The remaining digits are fractional digits, ndigits is '5' or
+             * smaller at this point.  It is certainly not zero.  Check for a
+             * non-zero fractional digit:
+             */
+            if (first <= 5)
+            {
+               unsigned int i;
+               *ascii++ = 46; /* decimal point */
+               /* ndigits may be <5 for small numbers, output leading zeros
+                * then ndigits digits to first:
+                */
+               i = 5;
+               while (ndigits < i)
+               {
+                  *ascii++ = 48; --i;
+               }
+               while (ndigits >= first) *ascii++ = digits[--ndigits];
+               /* Don't output the trailing zeros! */
+            }
+         }
+         else
+            *ascii++ = 48;
+
+         /* And null terminate the string: */
+         *ascii = 0;
+         return;
+      }
+   }
+
+   /* Here on buffer too small. */
+   png_error(png_ptr, "ASCII conversion buffer too small");
+}
+#   endif /* FIXED_POINT */
+#endif /* SCAL */
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
+   !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
+   (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
+   defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
+   (defined(PNG_sCAL_SUPPORTED) && \
+   defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
+png_fixed_point
+png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text)
+{
+   double r = floor(100000 * fp + .5);
+
+   if (r > 2147483647. || r < -2147483648.)
+      png_fixed_error(png_ptr, text);
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+   PNG_UNUSED(text)
+#  endif
+
+   return (png_fixed_point)r;
+}
+#endif
+
+#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_COLORSPACE_SUPPORTED) ||\
+    defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
+/* muldiv functions */
+/* This API takes signed arguments and rounds the result to the nearest
+ * integer (or, for a fixed point number - the standard argument - to
+ * the nearest .00001).  Overflow and divide by zero are signalled in
+ * the result, a boolean - true on success, false on overflow.
+ */
+#if GCC_STRICT_OVERFLOW /* from above */
+/* It is not obvious which comparison below gets optimized in such a way that
+ * signed overflow would change the result; looking through the code does not
+ * reveal any tests which have the form GCC complains about, so presumably the
+ * optimizer is moving an add or subtract into the 'if' somewhere.
+ */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic warning "-Wstrict-overflow=2"
+#endif /* GCC_STRICT_OVERFLOW */
+int
+png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
+    png_int_32 divisor)
+{
+   /* Return a * times / divisor, rounded. */
+   if (divisor != 0)
+   {
+      if (a == 0 || times == 0)
+      {
+         *res = 0;
+         return 1;
+      }
+      else
+      {
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+         double r = a;
+         r *= times;
+         r /= divisor;
+         r = floor(r+.5);
+
+         /* A png_fixed_point is a 32-bit integer. */
+         if (r <= 2147483647. && r >= -2147483648.)
+         {
+            *res = (png_fixed_point)r;
+            return 1;
+         }
+#else
+         int negative = 0;
+         png_uint_32 A, T, D;
+         png_uint_32 s16, s32, s00;
+
+         if (a < 0)
+            negative = 1, A = -a;
+         else
+            A = a;
+
+         if (times < 0)
+            negative = !negative, T = -times;
+         else
+            T = times;
+
+         if (divisor < 0)
+            negative = !negative, D = -divisor;
+         else
+            D = divisor;
+
+         /* Following can't overflow because the arguments only
+          * have 31 bits each, however the result may be 32 bits.
+          */
+         s16 = (A >> 16) * (T & 0xffff) +
+                           (A & 0xffff) * (T >> 16);
+         /* Can't overflow because the a*times bit is only 30
+          * bits at most.
+          */
+         s32 = (A >> 16) * (T >> 16) + (s16 >> 16);
+         s00 = (A & 0xffff) * (T & 0xffff);
+
+         s16 = (s16 & 0xffff) << 16;
+         s00 += s16;
+
+         if (s00 < s16)
+            ++s32; /* carry */
+
+         if (s32 < D) /* else overflow */
+         {
+            /* s32.s00 is now the 64-bit product, do a standard
+             * division, we know that s32 < D, so the maximum
+             * required shift is 31.
+             */
+            int bitshift = 32;
+            png_fixed_point result = 0; /* NOTE: signed */
+
+            while (--bitshift >= 0)
+            {
+               png_uint_32 d32, d00;
+
+               if (bitshift > 0)
+                  d32 = D >> (32-bitshift), d00 = D << bitshift;
+
+               else
+                  d32 = 0, d00 = D;
+
+               if (s32 > d32)
+               {
+                  if (s00 < d00) --s32; /* carry */
+                  s32 -= d32, s00 -= d00, result += 1<<bitshift;
+               }
+
+               else
+                  if (s32 == d32 && s00 >= d00)
+                     s32 = 0, s00 -= d00, result += 1<<bitshift;
+            }
+
+            /* Handle the rounding. */
+            if (s00 >= (D >> 1))
+               ++result;
+
+            if (negative != 0)
+               result = -result;
+
+            /* Check for overflow. */
+            if ((negative != 0 && result <= 0) ||
+                (negative == 0 && result >= 0))
+            {
+               *res = result;
+               return 1;
+            }
+         }
+#endif
+      }
+   }
+
+   return 0;
+}
+#if GCC_STRICT_OVERFLOW
+#pragma GCC diagnostic pop
+#endif /* GCC_STRICT_OVERFLOW */
+#endif /* READ_GAMMA || INCH_CONVERSIONS */
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+/* The following is for when the caller doesn't much care about the
+ * result.
+ */
+png_fixed_point
+png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times,
+    png_int_32 divisor)
+{
+   png_fixed_point result;
+
+   if (png_muldiv(&result, a, times, divisor) != 0)
+      return result;
+
+   png_warning(png_ptr, "fixed point overflow ignored");
+   return 0;
+}
+#endif
+
+#ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */
+/* Calculate a reciprocal, return 0 on div-by-zero or overflow. */
+png_fixed_point
+png_reciprocal(png_fixed_point a)
+{
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+   double r = floor(1E10/a+.5);
+
+   if (r <= 2147483647. && r >= -2147483648.)
+      return (png_fixed_point)r;
+#else
+   png_fixed_point res;
+
+   if (png_muldiv(&res, 100000, 100000, a) != 0)
+      return res;
+#endif
+
+   return 0; /* error/overflow */
+}
+
+/* This is the shared test on whether a gamma value is 'significant' - whether
+ * it is worth doing gamma correction.
+ */
+int /* PRIVATE */
+png_gamma_significant(png_fixed_point gamma_val)
+{
+   return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED ||
+       gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
+}
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+#ifdef PNG_16BIT_SUPPORTED
+/* A local convenience routine. */
+static png_fixed_point
+png_product2(png_fixed_point a, png_fixed_point b)
+{
+   /* The required result is 1/a * 1/b; the following preserves accuracy. */
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+   double r = a * 1E-5;
+   r *= b;
+   r = floor(r+.5);
+
+   if (r <= 2147483647. && r >= -2147483648.)
+      return (png_fixed_point)r;
+#else
+   png_fixed_point res;
+
+   if (png_muldiv(&res, a, b, 100000) != 0)
+      return res;
+#endif
+
+   return 0; /* overflow */
+}
+#endif /* 16BIT */
+
+/* The inverse of the above. */
+png_fixed_point
+png_reciprocal2(png_fixed_point a, png_fixed_point b)
+{
+   /* The required result is 1/a * 1/b; the following preserves accuracy. */
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+   if (a != 0 && b != 0)
+   {
+      double r = 1E15/a;
+      r /= b;
+      r = floor(r+.5);
+
+      if (r <= 2147483647. && r >= -2147483648.)
+         return (png_fixed_point)r;
+   }
+#else
+   /* This may overflow because the range of png_fixed_point isn't symmetric,
+    * but this API is only used for the product of file and screen gamma so it
+    * doesn't matter that the smallest number it can produce is 1/21474, not
+    * 1/100000
+    */
+   png_fixed_point res = png_product2(a, b);
+
+   if (res != 0)
+      return png_reciprocal(res);
+#endif
+
+   return 0; /* overflow */
+}
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */
+#ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED
+/* Fixed point gamma.
+ *
+ * The code to calculate the tables used below can be found in the shell script
+ * contrib/tools/intgamma.sh
+ *
+ * To calculate gamma this code implements fast log() and exp() calls using only
+ * fixed point arithmetic.  This code has sufficient precision for either 8-bit
+ * or 16-bit sample values.
+ *
+ * The tables used here were calculated using simple 'bc' programs, but C double
+ * precision floating point arithmetic would work fine.
+ *
+ * 8-bit log table
+ *   This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
+ *   255, so it's the base 2 logarithm of a normalized 8-bit floating point
+ *   mantissa.  The numbers are 32-bit fractions.
+ */
+static const png_uint_32
+png_8bit_l2[128] =
+{
+   4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
+   3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
+   3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
+   3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U,
+   3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U,
+   2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U,
+   2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U,
+   2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U,
+   2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U,
+   2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U,
+   1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U,
+   1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U,
+   1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U,
+   1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U,
+   1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U,
+   971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U,
+   803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U,
+   639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U,
+   479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U,
+   324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
+   172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
+   24347096U, 0U
+
+#if 0
+   /* The following are the values for 16-bit tables - these work fine for the
+    * 8-bit conversions but produce very slightly larger errors in the 16-bit
+    * log (about 1.2 as opposed to 0.7 absolute error in the final value).  To
+    * use these all the shifts below must be adjusted appropriately.
+    */
+   65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
+   57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
+   50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068,
+   43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782,
+   37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887,
+   31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339,
+   25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098,
+   20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132,
+   15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415,
+   10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523,
+   6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495,
+   1119, 744, 372
+#endif
+};
+
+static png_int_32
+png_log8bit(unsigned int x)
+{
+   unsigned int lg2 = 0;
+   /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log,
+    * because the log is actually negate that means adding 1.  The final
+    * returned value thus has the range 0 (for 255 input) to 7.994 (for 1
+    * input), return -1 for the overflow (log 0) case, - so the result is
+    * always at most 19 bits.
+    */
+   if ((x &= 0xff) == 0)
+      return -1;
+
+   if ((x & 0xf0) == 0)
+      lg2  = 4, x <<= 4;
+
+   if ((x & 0xc0) == 0)
+      lg2 += 2, x <<= 2;
+
+   if ((x & 0x80) == 0)
+      lg2 += 1, x <<= 1;
+
+   /* result is at most 19 bits, so this cast is safe: */
+   return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16));
+}
+
+/* The above gives exact (to 16 binary places) log2 values for 8-bit images,
+ * for 16-bit images we use the most significant 8 bits of the 16-bit value to
+ * get an approximation then multiply the approximation by a correction factor
+ * determined by the remaining up to 8 bits.  This requires an additional step
+ * in the 16-bit case.
+ *
+ * We want log2(value/65535), we have log2(v'/255), where:
+ *
+ *    value = v' * 256 + v''
+ *          = v' * f
+ *
+ * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
+ * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
+ * than 258.  The final factor also needs to correct for the fact that our 8-bit
+ * value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
+ *
+ * This gives a final formula using a calculated value 'x' which is value/v' and
+ * scaling by 65536 to match the above table:
+ *
+ *   log2(x/257) * 65536
+ *
+ * Since these numbers are so close to '1' we can use simple linear
+ * interpolation between the two end values 256/257 (result -368.61) and 258/257
+ * (result 367.179).  The values used below are scaled by a further 64 to give
+ * 16-bit precision in the interpolation:
+ *
+ * Start (256): -23591
+ * Zero  (257):      0
+ * End   (258):  23499
+ */
+#ifdef PNG_16BIT_SUPPORTED
+static png_int_32
+png_log16bit(png_uint_32 x)
+{
+   unsigned int lg2 = 0;
+
+   /* As above, but now the input has 16 bits. */
+   if ((x &= 0xffff) == 0)
+      return -1;
+
+   if ((x & 0xff00) == 0)
+      lg2  = 8, x <<= 8;
+
+   if ((x & 0xf000) == 0)
+      lg2 += 4, x <<= 4;
+
+   if ((x & 0xc000) == 0)
+      lg2 += 2, x <<= 2;
+
+   if ((x & 0x8000) == 0)
+      lg2 += 1, x <<= 1;
+
+   /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
+    * value.
+    */
+   lg2 <<= 28;
+   lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4;
+
+   /* Now we need to interpolate the factor, this requires a division by the top
+    * 8 bits.  Do this with maximum precision.
+    */
+   x = ((x << 16) + (x >> 9)) / (x >> 8);
+
+   /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24,
+    * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly
+    * 16 bits to interpolate to get the low bits of the result.  Round the
+    * answer.  Note that the end point values are scaled by 64 to retain overall
+    * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust
+    * the overall scaling by 6-12.  Round at every step.
+    */
+   x -= 1U << 24;
+
+   if (x <= 65536U) /* <= '257' */
+      lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12);
+
+   else
+      lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12);
+
+   /* Safe, because the result can't have more than 20 bits: */
+   return (png_int_32)((lg2 + 2048) >> 12);
+}
+#endif /* 16BIT */
+
+/* The 'exp()' case must invert the above, taking a 20-bit fixed point
+ * logarithmic value and returning a 16 or 8-bit number as appropriate.  In
+ * each case only the low 16 bits are relevant - the fraction - since the
+ * integer bits (the top 4) simply determine a shift.
+ *
+ * The worst case is the 16-bit distinction between 65535 and 65534. This
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
+ * distinguish log2(65535/65534.5) - 10^-5 or 17 bits.  There is little chance
+ * of getting this accuracy in practice.
+ *
+ * To deal with this the following exp() function works out the exponent of the
+ * fractional part of the logarithm by using an accurate 32-bit value from the
+ * top four fractional bits then multiplying in the remaining bits.
+ */
+static const png_uint_32
+png_32bit_exp[16] =
+{
+   /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
+   4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
+   3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
+   2553802834U, 2445529972U, 2341847524U, 2242560872U
+};
+
+/* Adjustment table; provided to explain the numbers in the code below. */
+#if 0
+for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
+   11 44937.64284865548751208448
+   10 45180.98734845585101160448
+    9 45303.31936980687359311872
+    8 45364.65110595323018870784
+    7 45395.35850361789624614912
+    6 45410.72259715102037508096
+    5 45418.40724413220722311168
+    4 45422.25021786898173001728
+    3 45424.17186732298419044352
+    2 45425.13273269940811464704
+    1 45425.61317555035558641664
+    0 45425.85339951654943850496
+#endif
+
+static png_uint_32
+png_exp(png_fixed_point x)
+{
+   if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
+   {
+      /* Obtain a 4-bit approximation */
+      png_uint_32 e = png_32bit_exp[(x >> 12) & 0x0f];
+
+      /* Incorporate the low 12 bits - these decrease the returned value by
+       * multiplying by a number less than 1 if the bit is set.  The multiplier
+       * is determined by the above table and the shift. Notice that the values
+       * converge on 45426 and this is used to allow linear interpolation of the
+       * low bits.
+       */
+      if (x & 0x800)
+         e -= (((e >> 16) * 44938U) +  16U) >> 5;
+
+      if (x & 0x400)
+         e -= (((e >> 16) * 45181U) +  32U) >> 6;
+
+      if (x & 0x200)
+         e -= (((e >> 16) * 45303U) +  64U) >> 7;
+
+      if (x & 0x100)
+         e -= (((e >> 16) * 45365U) + 128U) >> 8;
+
+      if (x & 0x080)
+         e -= (((e >> 16) * 45395U) + 256U) >> 9;
+
+      if (x & 0x040)
+         e -= (((e >> 16) * 45410U) + 512U) >> 10;
+
+      /* And handle the low 6 bits in a single block. */
+      e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9;
+
+      /* Handle the upper bits of x. */
+      e >>= x >> 16;
+      return e;
+   }
+
+   /* Check for overflow */
+   if (x <= 0)
+      return png_32bit_exp[0];
+
+   /* Else underflow */
+   return 0;
+}
+
+static png_byte
+png_exp8bit(png_fixed_point lg2)
+{
+   /* Get a 32-bit value: */
+   png_uint_32 x = png_exp(lg2);
+
+   /* Convert the 32-bit value to 0..255 by multiplying by 256-1. Note that the
+    * second, rounding, step can't overflow because of the first, subtraction,
+    * step.
+    */
+   x -= x >> 8;
+   return (png_byte)(((x + 0x7fffffU) >> 24) & 0xff);
+}
+
+#ifdef PNG_16BIT_SUPPORTED
+static png_uint_16
+png_exp16bit(png_fixed_point lg2)
+{
+   /* Get a 32-bit value: */
+   png_uint_32 x = png_exp(lg2);
+
+   /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
+   x -= x >> 16;
+   return (png_uint_16)((x + 32767U) >> 16);
+}
+#endif /* 16BIT */
+#endif /* FLOATING_ARITHMETIC */
+
+png_byte
+png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
+{
+   if (value > 0 && value < 255)
+   {
+#     ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+         /* 'value' is unsigned, ANSI-C90 requires the compiler to correctly
+          * convert this to a floating point value.  This includes values that
+          * would overflow if 'value' were to be converted to 'int'.
+          *
+          * Apparently GCC, however, does an intermediate conversion to (int)
+          * on some (ARM) but not all (x86) platforms, possibly because of
+          * hardware FP limitations.  (E.g. if the hardware conversion always
+          * assumes the integer register contains a signed value.)  This results
+          * in ANSI-C undefined behavior for large values.
+          *
+          * Other implementations on the same machine might actually be ANSI-C90
+          * conformant and therefore compile spurious extra code for the large
+          * values.
+          *
+          * We can be reasonably sure that an unsigned to float conversion
+          * won't be faster than an int to float one.  Therefore this code
+          * assumes responsibility for the undefined behavior, which it knows
+          * can't happen because of the check above.
+          *
+          * Note the argument to this routine is an (unsigned int) because, on
+          * 16-bit platforms, it is assigned a value which might be out of
+          * range for an (int); that would result in undefined behavior in the
+          * caller if the *argument* ('value') were to be declared (int).
+          */
+         double r = floor(255*pow((int)/*SAFE*/value/255.,gamma_val*.00001)+.5);
+         return (png_byte)r;
+#     else
+         png_int_32 lg2 = png_log8bit(value);
+         png_fixed_point res;
+
+         if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
+            return png_exp8bit(res);
+
+         /* Overflow. */
+         value = 0;
+#     endif
+   }
+
+   return (png_byte)(value & 0xff);
+}
+
+#ifdef PNG_16BIT_SUPPORTED
+png_uint_16
+png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val)
+{
+   if (value > 0 && value < 65535)
+   {
+# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+      /* The same (unsigned int)->(double) constraints apply here as above,
+       * however in this case the (unsigned int) to (int) conversion can
+       * overflow on an ANSI-C90 compliant system so the cast needs to ensure
+       * that this is not possible.
+       */
+      double r = floor(65535*pow((png_int_32)value/65535.,
+          gamma_val*.00001)+.5);
+      return (png_uint_16)r;
+# else
+      png_int_32 lg2 = png_log16bit(value);
+      png_fixed_point res;
+
+      if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
+         return png_exp16bit(res);
+
+      /* Overflow. */
+      value = 0;
+# endif
+   }
+
+   return (png_uint_16)value;
+}
+#endif /* 16BIT */
+
+/* This does the right thing based on the bit_depth field of the
+ * png_struct, interpreting values as 8-bit or 16-bit.  While the result
+ * is nominally a 16-bit value if bit depth is 8 then the result is
+ * 8-bit (as are the arguments.)
+ */
+png_uint_16 /* PRIVATE */
+png_gamma_correct(png_structrp png_ptr, unsigned int value,
+    png_fixed_point gamma_val)
+{
+   if (png_ptr->bit_depth == 8)
+      return png_gamma_8bit_correct(value, gamma_val);
+
+#ifdef PNG_16BIT_SUPPORTED
+   else
+      return png_gamma_16bit_correct(value, gamma_val);
+#else
+      /* should not reach this */
+      return 0;
+#endif /* 16BIT */
+}
+
+#ifdef PNG_16BIT_SUPPORTED
+/* Internal function to build a single 16-bit table - the table consists of
+ * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
+ * to shift the input values right (or 16-number_of_signifiant_bits).
+ *
+ * The caller is responsible for ensuring that the table gets cleaned up on
+ * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument
+ * should be somewhere that will be cleaned.
+ */
+static void
+png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable,
+    unsigned int shift, png_fixed_point gamma_val)
+{
+   /* Various values derived from 'shift': */
+   unsigned int num = 1U << (8U - shift);
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+   /* CSE the division and work round wacky GCC warnings (see the comments
+    * in png_gamma_8bit_correct for where these come from.)
+    */
+   double fmax = 1.0 / (((png_int_32)1 << (16U - shift)) - 1);
+#endif
+   unsigned int max = (1U << (16U - shift)) - 1U;
+   unsigned int max_by_2 = 1U << (15U - shift);
+   unsigned int i;
+
+   png_uint_16pp table = *ptable =
+       (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
+
+   for (i = 0; i < num; i++)
+   {
+      png_uint_16p sub_table = table[i] =
+          (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16)));
+
+      /* The 'threshold' test is repeated here because it can arise for one of
+       * the 16-bit tables even if the others don't hit it.
+       */
+      if (png_gamma_significant(gamma_val) != 0)
+      {
+         /* The old code would overflow at the end and this would cause the
+          * 'pow' function to return a result >1, resulting in an
+          * arithmetic error.  This code follows the spec exactly; ig is
+          * the recovered input sample, it always has 8-16 bits.
+          *
+          * We want input * 65535/max, rounded, the arithmetic fits in 32
+          * bits (unsigned) so long as max <= 32767.
+          */
+         unsigned int j;
+         for (j = 0; j < 256; j++)
+         {
+            png_uint_32 ig = (j << (8-shift)) + i;
+#           ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+               /* Inline the 'max' scaling operation: */
+               /* See png_gamma_8bit_correct for why the cast to (int) is
+                * required here.
+                */
+               double d = floor(65535.*pow(ig*fmax, gamma_val*.00001)+.5);
+               sub_table[j] = (png_uint_16)d;
+#           else
+               if (shift != 0)
+                  ig = (ig * 65535U + max_by_2)/max;
+
+               sub_table[j] = png_gamma_16bit_correct(ig, gamma_val);
+#           endif
+         }
+      }
+      else
+      {
+         /* We must still build a table, but do it the fast way. */
+         unsigned int j;
+
+         for (j = 0; j < 256; j++)
+         {
+            png_uint_32 ig = (j << (8-shift)) + i;
+
+            if (shift != 0)
+               ig = (ig * 65535U + max_by_2)/max;
+
+            sub_table[j] = (png_uint_16)ig;
+         }
+      }
+   }
+}
+
+/* NOTE: this function expects the *inverse* of the overall gamma transformation
+ * required.
+ */
+static void
+png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable,
+    unsigned int shift, png_fixed_point gamma_val)
+{
+   unsigned int num = 1U << (8U - shift);
+   unsigned int max = (1U << (16U - shift))-1U;
+   unsigned int i;
+   png_uint_32 last;
+
+   png_uint_16pp table = *ptable =
+       (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
+
+   /* 'num' is the number of tables and also the number of low bits of low
+    * bits of the input 16-bit value used to select a table.  Each table is
+    * itself indexed by the high 8 bits of the value.
+    */
+   for (i = 0; i < num; i++)
+      table[i] = (png_uint_16p)png_malloc(png_ptr,
+          256 * (sizeof (png_uint_16)));
+
+   /* 'gamma_val' is set to the reciprocal of the value calculated above, so
+    * pow(out,g) is an *input* value.  'last' is the last input value set.
+    *
+    * In the loop 'i' is used to find output values.  Since the output is
+    * 8-bit there are only 256 possible values.  The tables are set up to
+    * select the closest possible output value for each input by finding
+    * the input value at the boundary between each pair of output values
+    * and filling the table up to that boundary with the lower output
+    * value.
+    *
+    * The boundary values are 0.5,1.5..253.5,254.5.  Since these are 9-bit
+    * values the code below uses a 16-bit value in i; the values start at
+    * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
+    * entries are filled with 255).  Start i at 128 and fill all 'last'
+    * table entries <= 'max'
+    */
+   last = 0;
+   for (i = 0; i < 255; ++i) /* 8-bit output value */
+   {
+      /* Find the corresponding maximum input value */
+      png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */
+
+      /* Find the boundary value in 16 bits: */
+      png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val);
+
+      /* Adjust (round) to (16-shift) bits: */
+      bound = (bound * max + 32768U)/65535U + 1U;
+
+      while (last < bound)
+      {
+         table[last & (0xffU >> shift)][last >> (8U - shift)] = out;
+         last++;
+      }
+   }
+
+   /* And fill in the final entries. */
+   while (last < (num << 8))
+   {
+      table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U;
+      last++;
+   }
+}
+#endif /* 16BIT */
+
+/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
+ * typically much faster).  Note that libpng currently does no sBIT processing
+ * (apparently contrary to the spec) so a 256-entry table is always generated.
+ */
+static void
+png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,
+    png_fixed_point gamma_val)
+{
+   unsigned int i;
+   png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256);
+
+   if (png_gamma_significant(gamma_val) != 0)
+      for (i=0; i<256; i++)
+         table[i] = png_gamma_8bit_correct(i, gamma_val);
+
+   else
+      for (i=0; i<256; ++i)
+         table[i] = (png_byte)(i & 0xff);
+}
+
+/* Used from png_read_destroy and below to release the memory used by the gamma
+ * tables.
+ */
+void /* PRIVATE */
+png_destroy_gamma_table(png_structrp png_ptr)
+{
+   png_free(png_ptr, png_ptr->gamma_table);
+   png_ptr->gamma_table = NULL;
+
+#ifdef PNG_16BIT_SUPPORTED
+   if (png_ptr->gamma_16_table != NULL)
+   {
+      int i;
+      int istop = (1 << (8 - png_ptr->gamma_shift));
+      for (i = 0; i < istop; i++)
+      {
+         png_free(png_ptr, png_ptr->gamma_16_table[i]);
+      }
+   png_free(png_ptr, png_ptr->gamma_16_table);
+   png_ptr->gamma_16_table = NULL;
+   }
+#endif /* 16BIT */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+   png_free(png_ptr, png_ptr->gamma_from_1);
+   png_ptr->gamma_from_1 = NULL;
+   png_free(png_ptr, png_ptr->gamma_to_1);
+   png_ptr->gamma_to_1 = NULL;
+
+#ifdef PNG_16BIT_SUPPORTED
+   if (png_ptr->gamma_16_from_1 != NULL)
+   {
+      int i;
+      int istop = (1 << (8 - png_ptr->gamma_shift));
+      for (i = 0; i < istop; i++)
+      {
+         png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
+      }
+   png_free(png_ptr, png_ptr->gamma_16_from_1);
+   png_ptr->gamma_16_from_1 = NULL;
+   }
+   if (png_ptr->gamma_16_to_1 != NULL)
+   {
+      int i;
+      int istop = (1 << (8 - png_ptr->gamma_shift));
+      for (i = 0; i < istop; i++)
+      {
+         png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
+      }
+   png_free(png_ptr, png_ptr->gamma_16_to_1);
+   png_ptr->gamma_16_to_1 = NULL;
+   }
+#endif /* 16BIT */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+}
+
+/* We build the 8- or 16-bit gamma tables here.  Note that for 16-bit
+ * tables, we don't make a full table if we are reducing to 8-bit in
+ * the future.  Note also how the gamma_16 tables are segmented so that
+ * we don't need to allocate > 64K chunks for a full 16-bit table.
+ */
+void /* PRIVATE */
+png_build_gamma_table(png_structrp png_ptr, int bit_depth)
+{
+   png_debug(1, "in png_build_gamma_table");
+
+   /* Remove any existing table; this copes with multiple calls to
+    * png_read_update_info. The warning is because building the gamma tables
+    * multiple times is a performance hit - it's harmless but the ability to
+    * call png_read_update_info() multiple times is new in 1.5.6 so it seems
+    * sensible to warn if the app introduces such a hit.
+    */
+   if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL)
+   {
+      png_warning(png_ptr, "gamma table being rebuilt");
+      png_destroy_gamma_table(png_ptr);
+   }
+
+   if (bit_depth <= 8)
+   {
+      png_build_8bit_table(png_ptr, &png_ptr->gamma_table,
+          png_ptr->screen_gamma > 0 ?
+          png_reciprocal2(png_ptr->colorspace.gamma,
+          png_ptr->screen_gamma) : PNG_FP_1);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+      if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
+      {
+         png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
+             png_reciprocal(png_ptr->colorspace.gamma));
+
+         png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1,
+             png_ptr->screen_gamma > 0 ?
+             png_reciprocal(png_ptr->screen_gamma) :
+             png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
+      }
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+   }
+#ifdef PNG_16BIT_SUPPORTED
+   else
+   {
+      png_byte shift, sig_bit;
+
+      if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      {
+         sig_bit = png_ptr->sig_bit.red;
+
+         if (png_ptr->sig_bit.green > sig_bit)
+            sig_bit = png_ptr->sig_bit.green;
+
+         if (png_ptr->sig_bit.blue > sig_bit)
+            sig_bit = png_ptr->sig_bit.blue;
+      }
+      else
+         sig_bit = png_ptr->sig_bit.gray;
+
+      /* 16-bit gamma code uses this equation:
+       *
+       *   ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
+       *
+       * Where 'iv' is the input color value and 'ov' is the output value -
+       * pow(iv, gamma).
+       *
+       * Thus the gamma table consists of up to 256 256-entry tables.  The table
+       * is selected by the (8-gamma_shift) most significant of the low 8 bits
+       * of the color value then indexed by the upper 8 bits:
+       *
+       *   table[low bits][high 8 bits]
+       *
+       * So the table 'n' corresponds to all those 'iv' of:
+       *
+       *   <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
+       *
+       */
+      if (sig_bit > 0 && sig_bit < 16U)
+         /* shift == insignificant bits */
+         shift = (png_byte)((16U - sig_bit) & 0xff);
+
+      else
+         shift = 0; /* keep all 16 bits */
+
+      if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
+      {
+         /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
+          * the significant bits in the *input* when the output will
+          * eventually be 8 bits.  By default it is 11.
+          */
+         if (shift < (16U - PNG_MAX_GAMMA_8))
+            shift = (16U - PNG_MAX_GAMMA_8);
+      }
+
+      if (shift > 8U)
+         shift = 8U; /* Guarantees at least one table! */
+
+      png_ptr->gamma_shift = shift;
+
+      /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now
+       * PNG_COMPOSE).  This effectively smashed the background calculation for
+       * 16-bit output because the 8-bit table assumes the result will be
+       * reduced to 8 bits.
+       */
+      if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
+          png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
+          png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma,
+          png_ptr->screen_gamma) : PNG_FP_1);
+
+      else
+          png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift,
+          png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma,
+          png_ptr->screen_gamma) : PNG_FP_1);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+      if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
+      {
+         png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
+             png_reciprocal(png_ptr->colorspace.gamma));
+
+         /* Notice that the '16 from 1' table should be full precision, however
+          * the lookup on this table still uses gamma_shift, so it can't be.
+          * TODO: fix this.
+          */
+         png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift,
+             png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
+             png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
+      }
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+   }
+#endif /* 16BIT */
+}
+#endif /* READ_GAMMA */
+
+/* HARDWARE OR SOFTWARE OPTION SUPPORT */
+#ifdef PNG_SET_OPTION_SUPPORTED
+int PNGAPI
+png_set_option(png_structrp png_ptr, int option, int onoff)
+{
+   if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
+      (option & 1) == 0)
+   {
+      png_uint_32 mask = 3U << option;
+      png_uint_32 setting = (2U + (onoff != 0)) << option;
+      png_uint_32 current = png_ptr->options;
+
+      png_ptr->options = (png_uint_32)((current & ~mask) | setting);
+
+      return (int)(current & mask) >> option;
+   }
+
+   return PNG_OPTION_INVALID;
+}
+#endif
+
+/* sRGB support */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+/* sRGB conversion tables; these are machine generated with the code in
+ * contrib/tools/makesRGB.c.  The actual sRGB transfer curve defined in the
+ * specification (see the article at https://en.wikipedia.org/wiki/SRGB)
+ * is used, not the gamma=1/2.2 approximation use elsewhere in libpng.
+ * The sRGB to linear table is exact (to the nearest 16-bit linear fraction).
+ * The inverse (linear to sRGB) table has accuracies as follows:
+ *
+ * For all possible (255*65535+1) input values:
+ *
+ *    error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact
+ *
+ * For the input values corresponding to the 65536 16-bit values:
+ *
+ *    error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact
+ *
+ * In all cases the inexact readings are only off by one.
+ */
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+/* The convert-to-sRGB table is only currently required for read. */
+const png_uint_16 png_sRGB_table[256] =
+{
+   0,20,40,60,80,99,119,139,
+   159,179,199,219,241,264,288,313,
+   340,367,396,427,458,491,526,562,
+   599,637,677,718,761,805,851,898,
+   947,997,1048,1101,1156,1212,1270,1330,
+   1391,1453,1517,1583,1651,1720,1790,1863,
+   1937,2013,2090,2170,2250,2333,2418,2504,
+   2592,2681,2773,2866,2961,3058,3157,3258,
+   3360,3464,3570,3678,3788,3900,4014,4129,
+   4247,4366,4488,4611,4736,4864,4993,5124,
+   5257,5392,5530,5669,5810,5953,6099,6246,
+   6395,6547,6700,6856,7014,7174,7335,7500,
+   7666,7834,8004,8177,8352,8528,8708,8889,
+   9072,9258,9445,9635,9828,10022,10219,10417,
+   10619,10822,11028,11235,11446,11658,11873,12090,
+   12309,12530,12754,12980,13209,13440,13673,13909,
+   14146,14387,14629,14874,15122,15371,15623,15878,
+   16135,16394,16656,16920,17187,17456,17727,18001,
+   18277,18556,18837,19121,19407,19696,19987,20281,
+   20577,20876,21177,21481,21787,22096,22407,22721,
+   23038,23357,23678,24002,24329,24658,24990,25325,
+   25662,26001,26344,26688,27036,27386,27739,28094,
+   28452,28813,29176,29542,29911,30282,30656,31033,
+   31412,31794,32179,32567,32957,33350,33745,34143,
+   34544,34948,35355,35764,36176,36591,37008,37429,
+   37852,38278,38706,39138,39572,40009,40449,40891,
+   41337,41785,42236,42690,43147,43606,44069,44534,
+   45002,45473,45947,46423,46903,47385,47871,48359,
+   48850,49344,49841,50341,50844,51349,51858,52369,
+   52884,53401,53921,54445,54971,55500,56032,56567,
+   57105,57646,58190,58737,59287,59840,60396,60955,
+   61517,62082,62650,63221,63795,64372,64952,65535
+};
+#endif /* SIMPLIFIED_READ */
+
+/* The base/delta tables are required for both read and write (but currently
+ * only the simplified versions.)
+ */
+const png_uint_16 png_sRGB_base[512] =
+{
+   128,1782,3383,4644,5675,6564,7357,8074,
+   8732,9346,9921,10463,10977,11466,11935,12384,
+   12816,13233,13634,14024,14402,14769,15125,15473,
+   15812,16142,16466,16781,17090,17393,17690,17981,
+   18266,18546,18822,19093,19359,19621,19879,20133,
+   20383,20630,20873,21113,21349,21583,21813,22041,
+   22265,22487,22707,22923,23138,23350,23559,23767,
+   23972,24175,24376,24575,24772,24967,25160,25352,
+   25542,25730,25916,26101,26284,26465,26645,26823,
+   27000,27176,27350,27523,27695,27865,28034,28201,
+   28368,28533,28697,28860,29021,29182,29341,29500,
+   29657,29813,29969,30123,30276,30429,30580,30730,
+   30880,31028,31176,31323,31469,31614,31758,31902,
+   32045,32186,32327,32468,32607,32746,32884,33021,
+   33158,33294,33429,33564,33697,33831,33963,34095,
+   34226,34357,34486,34616,34744,34873,35000,35127,
+   35253,35379,35504,35629,35753,35876,35999,36122,
+   36244,36365,36486,36606,36726,36845,36964,37083,
+   37201,37318,37435,37551,37668,37783,37898,38013,
+   38127,38241,38354,38467,38580,38692,38803,38915,
+   39026,39136,39246,39356,39465,39574,39682,39790,
+   39898,40005,40112,40219,40325,40431,40537,40642,
+   40747,40851,40955,41059,41163,41266,41369,41471,
+   41573,41675,41777,41878,41979,42079,42179,42279,
+   42379,42478,42577,42676,42775,42873,42971,43068,
+   43165,43262,43359,43456,43552,43648,43743,43839,
+   43934,44028,44123,44217,44311,44405,44499,44592,
+   44685,44778,44870,44962,45054,45146,45238,45329,
+   45420,45511,45601,45692,45782,45872,45961,46051,
+   46140,46229,46318,46406,46494,46583,46670,46758,
+   46846,46933,47020,47107,47193,47280,47366,47452,
+   47538,47623,47709,47794,47879,47964,48048,48133,
+   48217,48301,48385,48468,48552,48635,48718,48801,
+   48884,48966,49048,49131,49213,49294,49376,49458,
+   49539,49620,49701,49782,49862,49943,50023,50103,
+   50183,50263,50342,50422,50501,50580,50659,50738,
+   50816,50895,50973,51051,51129,51207,51285,51362,
+   51439,51517,51594,51671,51747,51824,51900,51977,
+   52053,52129,52205,52280,52356,52432,52507,52582,
+   52657,52732,52807,52881,52956,53030,53104,53178,
+   53252,53326,53400,53473,53546,53620,53693,53766,
+   53839,53911,53984,54056,54129,54201,54273,54345,
+   54417,54489,54560,54632,54703,54774,54845,54916,
+   54987,55058,55129,55199,55269,55340,55410,55480,
+   55550,55620,55689,55759,55828,55898,55967,56036,
+   56105,56174,56243,56311,56380,56448,56517,56585,
+   56653,56721,56789,56857,56924,56992,57059,57127,
+   57194,57261,57328,57395,57462,57529,57595,57662,
+   57728,57795,57861,57927,57993,58059,58125,58191,
+   58256,58322,58387,58453,58518,58583,58648,58713,
+   58778,58843,58908,58972,59037,59101,59165,59230,
+   59294,59358,59422,59486,59549,59613,59677,59740,
+   59804,59867,59930,59993,60056,60119,60182,60245,
+   60308,60370,60433,60495,60558,60620,60682,60744,
+   60806,60868,60930,60992,61054,61115,61177,61238,
+   61300,61361,61422,61483,61544,61605,61666,61727,
+   61788,61848,61909,61969,62030,62090,62150,62211,
+   62271,62331,62391,62450,62510,62570,62630,62689,
+   62749,62808,62867,62927,62986,63045,63104,63163,
+   63222,63281,63340,63398,63457,63515,63574,63632,
+   63691,63749,63807,63865,63923,63981,64039,64097,
+   64155,64212,64270,64328,64385,64443,64500,64557,
+   64614,64672,64729,64786,64843,64900,64956,65013,
+   65070,65126,65183,65239,65296,65352,65409,65465
+};
+
+const png_byte png_sRGB_delta[512] =
+{
+   207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54,
+   52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36,
+   35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28,
+   28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24,
+   23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21,
+   21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19,
+   19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17,
+   17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16,
+   16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15,
+   15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14,
+   14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13,
+   13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12,
+   12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,
+   12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11,
+   11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
+   11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
+   11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+   10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+   10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+   10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+   9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+   9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+   9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+   9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7,
+   7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+   7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+   7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
+};
+#endif /* SIMPLIFIED READ/WRITE sRGB support */
+
+/* SIMPLIFIED READ/WRITE SUPPORT */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+static int
+png_image_free_function(png_voidp argument)
+{
+   png_imagep image = png_voidcast(png_imagep, argument);
+   png_controlp cp = image->opaque;
+   png_control c;
+
+   /* Double check that we have a png_ptr - it should be impossible to get here
+    * without one.
+    */
+   if (cp->png_ptr == NULL)
+      return 0;
+
+   /* First free any data held in the control structure. */
+#  ifdef PNG_STDIO_SUPPORTED
+      if (cp->owned_file != 0)
+      {
+         FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr);
+         cp->owned_file = 0;
+
+         /* Ignore errors here. */
+         if (fp != NULL)
+         {
+            cp->png_ptr->io_ptr = NULL;
+            (void)fclose(fp);
+         }
+      }
+#  endif
+
+   /* Copy the control structure so that the original, allocated, version can be
+    * safely freed.  Notice that a png_error here stops the remainder of the
+    * cleanup, but this is probably fine because that would indicate bad memory
+    * problems anyway.
+    */
+   c = *cp;
+   image->opaque = &c;
+   png_free(c.png_ptr, cp);
+
+   /* Then the structures, calling the correct API. */
+   if (c.for_write != 0)
+   {
+#     ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+         png_destroy_write_struct(&c.png_ptr, &c.info_ptr);
+#     else
+         png_error(c.png_ptr, "simplified write not supported");
+#     endif
+   }
+   else
+   {
+#     ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+         png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL);
+#     else
+         png_error(c.png_ptr, "simplified read not supported");
+#     endif
+   }
+
+   /* Success. */
+   return 1;
+}
+
+void PNGAPI
+png_image_free(png_imagep image)
+{
+   /* Safely call the real function, but only if doing so is safe at this point
+    * (if not inside an error handling context).  Otherwise assume
+    * png_safe_execute will call this API after the return.
+    */
+   if (image != NULL && image->opaque != NULL &&
+      image->opaque->error_buf == NULL)
+   {
+      png_image_free_function(image);
+      image->opaque = NULL;
+   }
+}
+
+int /* PRIVATE */
+png_image_error(png_imagep image, png_const_charp error_message)
+{
+   /* Utility to log an error. */
+   png_safecat(image->message, (sizeof image->message), 0, error_message);
+   image->warning_or_error |= PNG_IMAGE_ERROR;
+   png_image_free(image);
+   return 0;
+}
+
+#endif /* SIMPLIFIED READ/WRITE */
+#endif /* READ || WRITE */
diff --git a/extern/libpng/png.h b/extern/libpng/png.h
new file mode 100644
index 0000000000..139eb0dc0f
--- /dev/null
+++ b/extern/libpng/png.h
@@ -0,0 +1,3247 @@
+
+/* png.h - header file for PNG reference library
+ *
+ * libpng version 1.6.37 - April 14, 2019
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license. (See LICENSE, below.)
+ *
+ * Authors and maintainers:
+ *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
+ *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
+ *   libpng versions 0.97, January 1998, through 1.6.35, July 2018:
+ *     Glenn Randers-Pehrson
+ *   libpng versions 1.6.36, December 2018, through 1.6.37, April 2019:
+ *     Cosmin Truta
+ *   See also "Contributing Authors", below.
+ */
+
+/*
+ * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
+ * =========================================
+ *
+ * PNG Reference Library License version 2
+ * ---------------------------------------
+ *
+ *  * Copyright (c) 1995-2019 The PNG Reference Library Authors.
+ *  * Copyright (c) 2018-2019 Cosmin Truta.
+ *  * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson.
+ *  * Copyright (c) 1996-1997 Andreas Dilger.
+ *  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * The software is supplied "as is", without warranty of any kind,
+ * express or implied, including, without limitation, the warranties
+ * of merchantability, fitness for a particular purpose, title, and
+ * non-infringement.  In no event shall the Copyright owners, or
+ * anyone distributing the software, be liable for any damages or
+ * other liability, whether in contract, tort or otherwise, arising
+ * from, out of, or in connection with the software, or the use or
+ * other dealings in the software, even if advised of the possibility
+ * of such damage.
+ *
+ * Permission is hereby granted to use, copy, modify, and distribute
+ * this software, or portions hereof, for any purpose, without fee,
+ * subject to the following restrictions:
+ *
+ *  1. The origin of this software must not be misrepresented; you
+ *     must not claim that you wrote the original software.  If you
+ *     use this software in a product, an acknowledgment in the product
+ *     documentation would be appreciated, but is not required.
+ *
+ *  2. Altered source versions must be plainly marked as such, and must
+ *     not be misrepresented as being the original software.
+ *
+ *  3. This Copyright notice may not be removed or altered from any
+ *     source or altered source distribution.
+ *
+ *
+ * PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
+ * -----------------------------------------------------------------------
+ *
+ * libpng versions 1.0.7, July 1, 2000, through 1.6.35, July 15, 2018 are
+ * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson, are
+ * derived from libpng-1.0.6, and are distributed according to the same
+ * disclaimer and license as libpng-1.0.6 with the following individuals
+ * added to the list of Contributing Authors:
+ *
+ *     Simon-Pierre Cadieux
+ *     Eric S. Raymond
+ *     Mans Rullgard
+ *     Cosmin Truta
+ *     Gilles Vollant
+ *     James Yu
+ *     Mandar Sahastrabuddhe
+ *     Google Inc.
+ *     Vadim Barkov
+ *
+ * and with the following additions to the disclaimer:
+ *
+ *     There is no warranty against interference with your enjoyment of
+ *     the library or against infringement.  There is no warranty that our
+ *     efforts or the library will fulfill any of your particular purposes
+ *     or needs.  This library is provided with all faults, and the entire
+ *     risk of satisfactory quality, performance, accuracy, and effort is
+ *     with the user.
+ *
+ * Some files in the "contrib" directory and some configure-generated
+ * files that are distributed with libpng have other copyright owners, and
+ * are released under other open source licenses.
+ *
+ * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
+ * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
+ * libpng-0.96, and are distributed according to the same disclaimer and
+ * license as libpng-0.96, with the following individuals added to the
+ * list of Contributing Authors:
+ *
+ *     Tom Lane
+ *     Glenn Randers-Pehrson
+ *     Willem van Schaik
+ *
+ * libpng versions 0.89, June 1996, through 0.96, May 1997, are
+ * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
+ * and are distributed according to the same disclaimer and license as
+ * libpng-0.88, with the following individuals added to the list of
+ * Contributing Authors:
+ *
+ *     John Bowler
+ *     Kevin Bracey
+ *     Sam Bushell
+ *     Magnus Holmgren
+ *     Greg Roelofs
+ *     Tom Tanner
+ *
+ * Some files in the "scripts" directory have other copyright owners,
+ * but are released under this license.
+ *
+ * libpng versions 0.5, May 1995, through 0.88, January 1996, are
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * For the purposes of this copyright and license, "Contributing Authors"
+ * is defined as the following set of individuals:
+ *
+ *     Andreas Dilger
+ *     Dave Martindale
+ *     Guy Eric Schalnat
+ *     Paul Schmidt
+ *     Tim Wegner
+ *
+ * The PNG Reference Library is supplied "AS IS".  The Contributing
+ * Authors and Group 42, Inc. disclaim all warranties, expressed or
+ * implied, including, without limitation, the warranties of
+ * merchantability and of fitness for any purpose.  The Contributing
+ * Authors and Group 42, Inc. assume no liability for direct, indirect,
+ * incidental, special, exemplary, or consequential damages, which may
+ * result from the use of the PNG Reference Library, even if advised of
+ * the possibility of such damage.
+ *
+ * Permission is hereby granted to use, copy, modify, and distribute this
+ * source code, or portions hereof, for any purpose, without fee, subject
+ * to the following restrictions:
+ *
+ *  1. The origin of this source code must not be misrepresented.
+ *
+ *  2. Altered versions must be plainly marked as such and must not
+ *     be misrepresented as being the original source.
+ *
+ *  3. This Copyright notice may not be removed or altered from any
+ *     source or altered source distribution.
+ *
+ * The Contributing Authors and Group 42, Inc. specifically permit,
+ * without fee, and encourage the use of this source code as a component
+ * to supporting the PNG file format in commercial products.  If you use
+ * this source code in a product, acknowledgment is not required but would
+ * be appreciated.
+ *
+ * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
+ *
+ * TRADEMARK
+ * =========
+ *
+ * The name "libpng" has not been registered by the Copyright owners
+ * as a trademark in any jurisdiction.  However, because libpng has
+ * been distributed and maintained world-wide, continually since 1995,
+ * the Copyright owners claim "common-law trademark protection" in any
+ * jurisdiction where common-law trademark is recognized.
+ */
+
+/*
+ * A "png_get_copyright" function is available, for convenient use in "about"
+ * boxes and the like:
+ *
+ *    printf("%s", png_get_copyright(NULL));
+ *
+ * Also, the PNG logo (in PNG format, of course) is supplied in the
+ * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
+ */
+
+/*
+ * The contributing authors would like to thank all those who helped
+ * with testing, bug fixes, and patience.  This wouldn't have been
+ * possible without all of you.
+ *
+ * Thanks to Frank J. T. Wojcik for helping with the documentation.
+ */
+
+/* Note about libpng version numbers:
+ *
+ *    Due to various miscommunications, unforeseen code incompatibilities
+ *    and occasional factors outside the authors' control, version numbering
+ *    on the library has not always been consistent and straightforward.
+ *    The following table summarizes matters since version 0.89c, which was
+ *    the first widely used release:
+ *
+ *    source                 png.h  png.h  shared-lib
+ *    version                string   int  version
+ *    -------                ------ -----  ----------
+ *    0.89c "1.0 beta 3"     0.89      89  1.0.89
+ *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
+ *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
+ *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
+ *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
+ *    0.97c                  0.97      97  2.0.97
+ *    0.98                   0.98      98  2.0.98
+ *    0.99                   0.99      98  2.0.99
+ *    0.99a-m                0.99      99  2.0.99
+ *    1.00                   1.00     100  2.1.0 [100 should be 10000]
+ *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
+ *    1.0.1       png.h string is   10001  2.1.0
+ *    1.0.1a-e    identical to the  10002  from here on, the shared library
+ *    1.0.2       source version)   10002  is 2.V where V is the source code
+ *    1.0.2a-b                      10003  version, except as noted.
+ *    1.0.3                         10003
+ *    1.0.3a-d                      10004
+ *    1.0.4                         10004
+ *    1.0.4a-f                      10005
+ *    1.0.5 (+ 2 patches)           10005
+ *    1.0.5a-d                      10006
+ *    1.0.5e-r                      10100 (not source compatible)
+ *    1.0.5s-v                      10006 (not binary compatible)
+ *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)
+ *    1.0.6d-f                      10007 (still binary incompatible)
+ *    1.0.6g                        10007
+ *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)
+ *    1.0.6i                        10007  10.6i
+ *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
+ *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
+ *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
+ *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
+ *    1.0.7                    1    10007  (still compatible)
+ *    ...
+ *    1.0.69                  10    10069  10.so.0.69[.0]
+ *    ...
+ *    1.2.59                  13    10259  12.so.0.59[.0]
+ *    ...
+ *    1.4.20                  14    10420  14.so.0.20[.0]
+ *    ...
+ *    1.5.30                  15    10530  15.so.15.30[.0]
+ *    ...
+ *    1.6.37                  16    10637  16.so.16.37[.0]
+ *
+ *    Henceforth the source version will match the shared-library major and
+ *    minor numbers; the shared-library major version number will be used for
+ *    changes in backward compatibility, as it is intended.
+ *    The PNG_LIBPNG_VER macro, which is not used within libpng but is
+ *    available for applications, is an unsigned integer of the form XYYZZ
+ *    corresponding to the source version X.Y.Z (leading zeros in Y and Z).
+ *    Beta versions were given the previous public release number plus a
+ *    letter, until version 1.0.6j; from then on they were given the upcoming
+ *    public release number plus "betaNN" or "rcNN".
+ *
+ *    Binary incompatibility exists only when applications make direct access
+ *    to the info_ptr or png_ptr members through png.h, and the compiled
+ *    application is loaded with a different version of the library.
+ *
+ *    DLLNUM will change each time there are forward or backward changes
+ *    in binary compatibility (e.g., when a new feature is added).
+ *
+ * See libpng.txt or libpng.3 for more information.  The PNG specification
+ * is available as a W3C Recommendation and as an ISO/IEC Standard; see
+ * <https://www.w3.org/TR/2003/REC-PNG-20031110/>
+ */
+
+#ifndef PNG_H
+#define PNG_H
+
+/* This is not the place to learn how to use libpng. The file libpng-manual.txt
+ * describes how to use libpng, and the file example.c summarizes it
+ * with some code on which to build.  This file is useful for looking
+ * at the actual function definitions and structure components.  If that
+ * file has been stripped from your copy of libpng, you can find it at
+ * <http://www.libpng.org/pub/png/libpng-manual.txt>
+ *
+ * If you just need to read a PNG file and don't want to read the documentation
+ * skip to the end of this file and read the section entitled 'simplified API'.
+ */
+
+/* Version information for png.h - this should match the version in png.c */
+#define PNG_LIBPNG_VER_STRING "1.6.37"
+#define PNG_HEADER_VERSION_STRING " libpng version 1.6.37 - April 14, 2019\n"
+
+#define PNG_LIBPNG_VER_SONUM   16
+#define PNG_LIBPNG_VER_DLLNUM  16
+
+/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
+#define PNG_LIBPNG_VER_MAJOR   1
+#define PNG_LIBPNG_VER_MINOR   6
+#define PNG_LIBPNG_VER_RELEASE 37
+
+/* This should be zero for a public release, or non-zero for a
+ * development version.  [Deprecated]
+ */
+#define PNG_LIBPNG_VER_BUILD  0
+
+/* Release Status */
+#define PNG_LIBPNG_BUILD_ALPHA    1
+#define PNG_LIBPNG_BUILD_BETA     2
+#define PNG_LIBPNG_BUILD_RC       3
+#define PNG_LIBPNG_BUILD_STABLE   4
+#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
+
+/* Release-Specific Flags */
+#define PNG_LIBPNG_BUILD_PATCH    8 /* Can be OR'ed with
+                                       PNG_LIBPNG_BUILD_STABLE only */
+#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
+                                       PNG_LIBPNG_BUILD_SPECIAL */
+#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
+                                       PNG_LIBPNG_BUILD_PRIVATE */
+
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
+
+/* Careful here.  At one time, Guy wanted to use 082, but that
+ * would be octal.  We must not include leading zeros.
+ * Versions 0.7 through 1.0.0 were in the range 0 to 100 here
+ * (only version 1.0.0 was mis-numbered 100 instead of 10000).
+ * From version 1.0.1 it is:
+ * XXYYZZ, where XX=major, YY=minor, ZZ=release
+ */
+#define PNG_LIBPNG_VER 10637 /* 1.6.37 */
+
+/* Library configuration: these options cannot be changed after
+ * the library has been built.
+ */
+#ifndef PNGLCONF_H
+/* If pnglibconf.h is missing, you can
+ * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
+ */
+#   include "pnglibconf.h"
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+/* Machine specific configuration. */
+#  include "pngconf.h"
+#endif
+
+/*
+ * Added at libpng-1.2.8
+ *
+ * Ref MSDN: Private as priority over Special
+ * VS_FF_PRIVATEBUILD File *was not* built using standard release
+ * procedures. If this value is given, the StringFileInfo block must
+ * contain a PrivateBuild string.
+ *
+ * VS_FF_SPECIALBUILD File *was* built by the original company using
+ * standard release procedures but is a variation of the standard
+ * file of the same version number. If this value is given, the
+ * StringFileInfo block must contain a SpecialBuild string.
+ */
+
+#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
+#  define PNG_LIBPNG_BUILD_TYPE \
+       (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
+#else
+#  ifdef PNG_LIBPNG_SPECIALBUILD
+#    define PNG_LIBPNG_BUILD_TYPE \
+         (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
+#  else
+#    define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
+#  endif
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+
+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* Version information for C files, stored in png.c.  This had better match
+ * the version above.
+ */
+#define png_libpng_ver png_get_header_ver(NULL)
+
+/* This file is arranged in several sections:
+ *
+ * 1. [omitted]
+ * 2. Any configuration options that can be specified by for the application
+ *    code when it is built.  (Build time configuration is in pnglibconf.h)
+ * 3. Type definitions (base types are defined in pngconf.h), structure
+ *    definitions.
+ * 4. Exported library functions.
+ * 5. Simplified API.
+ * 6. Implementation options.
+ *
+ * The library source code has additional files (principally pngpriv.h) that
+ * allow configuration of the library.
+ */
+
+/* Section 1: [omitted] */
+
+/* Section 2: run time configuration
+ * See pnglibconf.h for build time configuration
+ *
+ * Run time configuration allows the application to choose between
+ * implementations of certain arithmetic APIs.  The default is set
+ * at build time and recorded in pnglibconf.h, but it is safe to
+ * override these (and only these) settings.  Note that this won't
+ * change what the library does, only application code, and the
+ * settings can (and probably should) be made on a per-file basis
+ * by setting the #defines before including png.h
+ *
+ * Use macros to read integers from PNG data or use the exported
+ * functions?
+ *   PNG_USE_READ_MACROS: use the macros (see below)  Note that
+ *     the macros evaluate their argument multiple times.
+ *   PNG_NO_USE_READ_MACROS: call the relevant library function.
+ *
+ * Use the alternative algorithm for compositing alpha samples that
+ * does not use division?
+ *   PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
+ *      algorithm.
+ *   PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
+ *
+ * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
+ * false?
+ *   PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
+ *      APIs to png_warning.
+ * Otherwise the calls are mapped to png_error.
+ */
+
+/* Section 3: type definitions, including structures and compile time
+ * constants.
+ * See pngconf.h for base types that vary by machine/system
+ */
+
+/* This triggers a compiler error in png.c, if png.c and png.h
+ * do not agree upon the version number.
+ */
+typedef char* png_libpng_version_1_6_37;
+
+/* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
+ *
+ * png_struct is the cache of information used while reading or writing a single
+ * PNG file.  One of these is always required, although the simplified API
+ * (below) hides the creation and destruction of it.
+ */
+typedef struct png_struct_def png_struct;
+typedef const png_struct * png_const_structp;
+typedef png_struct * png_structp;
+typedef png_struct * * png_structpp;
+
+/* png_info contains information read from or to be written to a PNG file.  One
+ * or more of these must exist while reading or creating a PNG file.  The
+ * information is not used by libpng during read but is used to control what
+ * gets written when a PNG file is created.  "png_get_" function calls read
+ * information during read and "png_set_" functions calls write information
+ * when creating a PNG.
+ * been moved into a separate header file that is not accessible to
+ * applications.  Read libpng-manual.txt or libpng.3 for more info.
+ */
+typedef struct png_info_def png_info;
+typedef png_info * png_infop;
+typedef const png_info * png_const_infop;
+typedef png_info * * png_infopp;
+
+/* Types with names ending 'p' are pointer types.  The corresponding types with
+ * names ending 'rp' are identical pointer types except that the pointer is
+ * marked 'restrict', which means that it is the only pointer to the object
+ * passed to the function.  Applications should not use the 'restrict' types;
+ * it is always valid to pass 'p' to a pointer with a function argument of the
+ * corresponding 'rp' type.  Different compilers have different rules with
+ * regard to type matching in the presence of 'restrict'.  For backward
+ * compatibility libpng callbacks never have 'restrict' in their parameters and,
+ * consequentially, writing portable application code is extremely difficult if
+ * an attempt is made to use 'restrict'.
+ */
+typedef png_struct * PNG_RESTRICT png_structrp;
+typedef const png_struct * PNG_RESTRICT png_const_structrp;
+typedef png_info * PNG_RESTRICT png_inforp;
+typedef const png_info * PNG_RESTRICT png_const_inforp;
+
+/* Three color definitions.  The order of the red, green, and blue, (and the
+ * exact size) is not important, although the size of the fields need to
+ * be png_byte or png_uint_16 (as defined below).
+ */
+typedef struct png_color_struct
+{
+   png_byte red;
+   png_byte green;
+   png_byte blue;
+} png_color;
+typedef png_color * png_colorp;
+typedef const png_color * png_const_colorp;
+typedef png_color * * png_colorpp;
+
+typedef struct png_color_16_struct
+{
+   png_byte index;    /* used for palette files */
+   png_uint_16 red;   /* for use in red green blue files */
+   png_uint_16 green;
+   png_uint_16 blue;
+   png_uint_16 gray;  /* for use in grayscale files */
+} png_color_16;
+typedef png_color_16 * png_color_16p;
+typedef const png_color_16 * png_const_color_16p;
+typedef png_color_16 * * png_color_16pp;
+
+typedef struct png_color_8_struct
+{
+   png_byte red;   /* for use in red green blue files */
+   png_byte green;
+   png_byte blue;
+   png_byte gray;  /* for use in grayscale files */
+   png_byte alpha; /* for alpha channel files */
+} png_color_8;
+typedef png_color_8 * png_color_8p;
+typedef const png_color_8 * png_const_color_8p;
+typedef png_color_8 * * png_color_8pp;
+
+/*
+ * The following two structures are used for the in-core representation
+ * of sPLT chunks.
+ */
+typedef struct png_sPLT_entry_struct
+{
+   png_uint_16 red;
+   png_uint_16 green;
+   png_uint_16 blue;
+   png_uint_16 alpha;
+   png_uint_16 frequency;
+} png_sPLT_entry;
+typedef png_sPLT_entry * png_sPLT_entryp;
+typedef const png_sPLT_entry * png_const_sPLT_entryp;
+typedef png_sPLT_entry * * png_sPLT_entrypp;
+
+/*  When the depth of the sPLT palette is 8 bits, the color and alpha samples
+ *  occupy the LSB of their respective members, and the MSB of each member
+ *  is zero-filled.  The frequency member always occupies the full 16 bits.
+ */
+
+typedef struct png_sPLT_struct
+{
+   png_charp name;           /* palette name */
+   png_byte depth;           /* depth of palette samples */
+   png_sPLT_entryp entries;  /* palette entries */
+   png_int_32 nentries;      /* number of palette entries */
+} png_sPLT_t;
+typedef png_sPLT_t * png_sPLT_tp;
+typedef const png_sPLT_t * png_const_sPLT_tp;
+typedef png_sPLT_t * * png_sPLT_tpp;
+
+#ifdef PNG_TEXT_SUPPORTED
+/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
+ * and whether that contents is compressed or not.  The "key" field
+ * points to a regular zero-terminated C string.  The "text" fields can be a
+ * regular C string, an empty string, or a NULL pointer.
+ * However, the structure returned by png_get_text() will always contain
+ * the "text" field as a regular zero-terminated C string (possibly
+ * empty), never a NULL pointer, so it can be safely used in printf() and
+ * other string-handling functions.  Note that the "itxt_length", "lang", and
+ * "lang_key" members of the structure only exist when the library is built
+ * with iTXt chunk support.  Prior to libpng-1.4.0 the library was built by
+ * default without iTXt support. Also note that when iTXt *is* supported,
+ * the "lang" and "lang_key" fields contain NULL pointers when the
+ * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
+ * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
+ * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
+ * which is always 0 or 1, or its "compression method" which is always 0.
+ */
+typedef struct png_text_struct
+{
+   int  compression;       /* compression value:
+                             -1: tEXt, none
+                              0: zTXt, deflate
+                              1: iTXt, none
+                              2: iTXt, deflate  */
+   png_charp key;          /* keyword, 1-79 character description of "text" */
+   png_charp text;         /* comment, may be an empty string (ie "")
+                              or a NULL pointer */
+   size_t text_length;     /* length of the text string */
+   size_t itxt_length;     /* length of the itxt string */
+   png_charp lang;         /* language code, 0-79 characters
+                              or a NULL pointer */
+   png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
+                              chars or a NULL pointer */
+} png_text;
+typedef png_text * png_textp;
+typedef const png_text * png_const_textp;
+typedef png_text * * png_textpp;
+#endif
+
+/* Supported compression types for text in PNG files (tEXt, and zTXt).
+ * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
+#define PNG_TEXT_COMPRESSION_NONE_WR -3
+#define PNG_TEXT_COMPRESSION_zTXt_WR -2
+#define PNG_TEXT_COMPRESSION_NONE    -1
+#define PNG_TEXT_COMPRESSION_zTXt     0
+#define PNG_ITXT_COMPRESSION_NONE     1
+#define PNG_ITXT_COMPRESSION_zTXt     2
+#define PNG_TEXT_COMPRESSION_LAST     3  /* Not a valid value */
+
+/* png_time is a way to hold the time in an machine independent way.
+ * Two conversions are provided, both from time_t and struct tm.  There
+ * is no portable way to convert to either of these structures, as far
+ * as I know.  If you know of a portable way, send it to me.  As a side
+ * note - PNG has always been Year 2000 compliant!
+ */
+typedef struct png_time_struct
+{
+   png_uint_16 year; /* full year, as in, 1995 */
+   png_byte month;   /* month of year, 1 - 12 */
+   png_byte day;     /* day of month, 1 - 31 */
+   png_byte hour;    /* hour of day, 0 - 23 */
+   png_byte minute;  /* minute of hour, 0 - 59 */
+   png_byte second;  /* second of minute, 0 - 60 (for leap seconds) */
+} png_time;
+typedef png_time * png_timep;
+typedef const png_time * png_const_timep;
+typedef png_time * * png_timepp;
+
+#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
+   defined(PNG_USER_CHUNKS_SUPPORTED)
+/* png_unknown_chunk is a structure to hold queued chunks for which there is
+ * no specific support.  The idea is that we can use this to queue
+ * up private chunks for output even though the library doesn't actually
+ * know about their semantics.
+ *
+ * The data in the structure is set by libpng on read and used on write.
+ */
+typedef struct png_unknown_chunk_t
+{
+   png_byte name[5]; /* Textual chunk name with '\0' terminator */
+   png_byte *data;   /* Data, should not be modified on read! */
+   size_t size;
+
+   /* On write 'location' must be set using the flag values listed below.
+    * Notice that on read it is set by libpng however the values stored have
+    * more bits set than are listed below.  Always treat the value as a
+    * bitmask.  On write set only one bit - setting multiple bits may cause the
+    * chunk to be written in multiple places.
+    */
+   png_byte location; /* mode of operation at read time */
+}
+png_unknown_chunk;
+
+typedef png_unknown_chunk * png_unknown_chunkp;
+typedef const png_unknown_chunk * png_const_unknown_chunkp;
+typedef png_unknown_chunk * * png_unknown_chunkpp;
+#endif
+
+/* Flag values for the unknown chunk location byte. */
+#define PNG_HAVE_IHDR  0x01
+#define PNG_HAVE_PLTE  0x02
+#define PNG_AFTER_IDAT 0x08
+
+/* Maximum positive integer used in PNG is (2^31)-1 */
+#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
+#define PNG_UINT_32_MAX ((png_uint_32)(-1))
+#define PNG_SIZE_MAX ((size_t)(-1))
+
+/* These are constants for fixed point values encoded in the
+ * PNG specification manner (x100000)
+ */
+#define PNG_FP_1    100000
+#define PNG_FP_HALF  50000
+#define PNG_FP_MAX  ((png_fixed_point)0x7fffffffL)
+#define PNG_FP_MIN  (-PNG_FP_MAX)
+
+/* These describe the color_type field in png_info. */
+/* color type masks */
+#define PNG_COLOR_MASK_PALETTE    1
+#define PNG_COLOR_MASK_COLOR      2
+#define PNG_COLOR_MASK_ALPHA      4
+
+/* color types.  Note that not all combinations are legal */
+#define PNG_COLOR_TYPE_GRAY 0
+#define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
+#define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
+#define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
+#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
+/* aliases */
+#define PNG_COLOR_TYPE_RGBA  PNG_COLOR_TYPE_RGB_ALPHA
+#define PNG_COLOR_TYPE_GA  PNG_COLOR_TYPE_GRAY_ALPHA
+
+/* This is for compression type. PNG 1.0-1.2 only define the single type. */
+#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
+#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
+
+/* This is for filter type. PNG 1.0-1.2 only define the single type. */
+#define PNG_FILTER_TYPE_BASE      0 /* Single row per-byte filtering */
+#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
+#define PNG_FILTER_TYPE_DEFAULT   PNG_FILTER_TYPE_BASE
+
+/* These are for the interlacing type.  These values should NOT be changed. */
+#define PNG_INTERLACE_NONE        0 /* Non-interlaced image */
+#define PNG_INTERLACE_ADAM7       1 /* Adam7 interlacing */
+#define PNG_INTERLACE_LAST        2 /* Not a valid value */
+
+/* These are for the oFFs chunk.  These values should NOT be changed. */
+#define PNG_OFFSET_PIXEL          0 /* Offset in pixels */
+#define PNG_OFFSET_MICROMETER     1 /* Offset in micrometers (1/10^6 meter) */
+#define PNG_OFFSET_LAST           2 /* Not a valid value */
+
+/* These are for the pCAL chunk.  These values should NOT be changed. */
+#define PNG_EQUATION_LINEAR       0 /* Linear transformation */
+#define PNG_EQUATION_BASE_E       1 /* Exponential base e transform */
+#define PNG_EQUATION_ARBITRARY    2 /* Arbitrary base exponential transform */
+#define PNG_EQUATION_HYPERBOLIC   3 /* Hyperbolic sine transformation */
+#define PNG_EQUATION_LAST         4 /* Not a valid value */
+
+/* These are for the sCAL chunk.  These values should NOT be changed. */
+#define PNG_SCALE_UNKNOWN         0 /* unknown unit (image scale) */
+#define PNG_SCALE_METER           1 /* meters per pixel */
+#define PNG_SCALE_RADIAN          2 /* radians per pixel */
+#define PNG_SCALE_LAST            3 /* Not a valid value */
+
+/* These are for the pHYs chunk.  These values should NOT be changed. */
+#define PNG_RESOLUTION_UNKNOWN    0 /* pixels/unknown unit (aspect ratio) */
+#define PNG_RESOLUTION_METER      1 /* pixels/meter */
+#define PNG_RESOLUTION_LAST       2 /* Not a valid value */
+
+/* These are for the sRGB chunk.  These values should NOT be changed. */
+#define PNG_sRGB_INTENT_PERCEPTUAL 0
+#define PNG_sRGB_INTENT_RELATIVE   1
+#define PNG_sRGB_INTENT_SATURATION 2
+#define PNG_sRGB_INTENT_ABSOLUTE   3
+#define PNG_sRGB_INTENT_LAST       4 /* Not a valid value */
+
+/* This is for text chunks */
+#define PNG_KEYWORD_MAX_LENGTH     79
+
+/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
+#define PNG_MAX_PALETTE_LENGTH    256
+
+/* These determine if an ancillary chunk's data has been successfully read
+ * from the PNG header, or if the application has filled in the corresponding
+ * data in the info_struct to be written into the output file.  The values
+ * of the PNG_INFO_<chunk> defines should NOT be changed.
+ */
+#define PNG_INFO_gAMA 0x0001U
+#define PNG_INFO_sBIT 0x0002U
+#define PNG_INFO_cHRM 0x0004U
+#define PNG_INFO_PLTE 0x0008U
+#define PNG_INFO_tRNS 0x0010U
+#define PNG_INFO_bKGD 0x0020U
+#define PNG_INFO_hIST 0x0040U
+#define PNG_INFO_pHYs 0x0080U
+#define PNG_INFO_oFFs 0x0100U
+#define PNG_INFO_tIME 0x0200U
+#define PNG_INFO_pCAL 0x0400U
+#define PNG_INFO_sRGB 0x0800U  /* GR-P, 0.96a */
+#define PNG_INFO_iCCP 0x1000U  /* ESR, 1.0.6 */
+#define PNG_INFO_sPLT 0x2000U  /* ESR, 1.0.6 */
+#define PNG_INFO_sCAL 0x4000U  /* ESR, 1.0.6 */
+#define PNG_INFO_IDAT 0x8000U  /* ESR, 1.0.6 */
+#define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */
+
+/* This is used for the transformation routines, as some of them
+ * change these values for the row.  It also should enable using
+ * the routines for other purposes.
+ */
+typedef struct png_row_info_struct
+{
+   png_uint_32 width;    /* width of row */
+   size_t rowbytes;      /* number of bytes in row */
+   png_byte color_type;  /* color type of row */
+   png_byte bit_depth;   /* bit depth of row */
+   png_byte channels;    /* number of channels (1, 2, 3, or 4) */
+   png_byte pixel_depth; /* bits per pixel (depth * channels) */
+} png_row_info;
+
+typedef png_row_info * png_row_infop;
+typedef png_row_info * * png_row_infopp;
+
+/* These are the function types for the I/O functions and for the functions
+ * that allow the user to override the default I/O functions with his or her
+ * own.  The png_error_ptr type should match that of user-supplied warning
+ * and error functions, while the png_rw_ptr type should match that of the
+ * user read/write data functions.  Note that the 'write' function must not
+ * modify the buffer it is passed. The 'read' function, on the other hand, is
+ * expected to return the read data in the buffer.
+ */
+typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
+typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
+typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
+typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
+    int));
+typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
+    int));
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
+typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
+
+/* The following callback receives png_uint_32 row_number, int pass for the
+ * png_bytep data of the row.  When transforming an interlaced image the
+ * row number is the row number within the sub-image of the interlace pass, so
+ * the value will increase to the height of the sub-image (not the full image)
+ * then reset to 0 for the next pass.
+ *
+ * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+ * find the output pixel (x,y) given an interlaced sub-image pixel
+ * (row,col,pass).  (See below for these macros.)
+ */
+typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
+    png_uint_32, int));
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
+    png_bytep));
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
+    png_unknown_chunkp));
+#endif
+#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
+/* not used anywhere */
+/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+/* This must match the function definition in <setjmp.h>, and the application
+ * must include this before png.h to obtain the definition of jmp_buf.  The
+ * function is required to be PNG_NORETURN, but this is not checked.  If the
+ * function does return the application will crash via an abort() or similar
+ * system level call.
+ *
+ * If you get a warning here while building the library you may need to make
+ * changes to ensure that pnglibconf.h records the calling convention used by
+ * your compiler.  This may be very difficult - try using a different compiler
+ * to build the library!
+ */
+PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
+#endif
+
+/* Transform masks for the high-level interface */
+#define PNG_TRANSFORM_IDENTITY       0x0000    /* read and write */
+#define PNG_TRANSFORM_STRIP_16       0x0001    /* read only */
+#define PNG_TRANSFORM_STRIP_ALPHA    0x0002    /* read only */
+#define PNG_TRANSFORM_PACKING        0x0004    /* read and write */
+#define PNG_TRANSFORM_PACKSWAP       0x0008    /* read and write */
+#define PNG_TRANSFORM_EXPAND         0x0010    /* read only */
+#define PNG_TRANSFORM_INVERT_MONO    0x0020    /* read and write */
+#define PNG_TRANSFORM_SHIFT          0x0040    /* read and write */
+#define PNG_TRANSFORM_BGR            0x0080    /* read and write */
+#define PNG_TRANSFORM_SWAP_ALPHA     0x0100    /* read and write */
+#define PNG_TRANSFORM_SWAP_ENDIAN    0x0200    /* read and write */
+#define PNG_TRANSFORM_INVERT_ALPHA   0x0400    /* read and write */
+#define PNG_TRANSFORM_STRIP_FILLER   0x0800    /* write only */
+/* Added to libpng-1.2.34 */
+#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
+#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
+/* Added to libpng-1.4.0 */
+#define PNG_TRANSFORM_GRAY_TO_RGB   0x2000      /* read only */
+/* Added to libpng-1.5.4 */
+#define PNG_TRANSFORM_EXPAND_16     0x4000      /* read only */
+#if INT_MAX >= 0x8000 /* else this might break */
+#define PNG_TRANSFORM_SCALE_16      0x8000      /* read only */
+#endif
+
+/* Flags for MNG supported features */
+#define PNG_FLAG_MNG_EMPTY_PLTE     0x01
+#define PNG_FLAG_MNG_FILTER_64      0x04
+#define PNG_ALL_MNG_FEATURES        0x05
+
+/* NOTE: prior to 1.5 these functions had no 'API' style declaration,
+ * this allowed the zlib default functions to be used on Windows
+ * platforms.  In 1.5 the zlib default malloc (which just calls malloc and
+ * ignores the first argument) should be completely compatible with the
+ * following.
+ */
+typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
+    png_alloc_size_t));
+typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
+
+/* Section 4: exported functions
+ * Here are the function definitions most commonly used.  This is not
+ * the place to find out how to use libpng.  See libpng-manual.txt for the
+ * full explanation, see example.c for the summary.  This just provides
+ * a simple one line description of the use of each function.
+ *
+ * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
+ * pngconf.h and in the *.dfn files in the scripts directory.
+ *
+ *   PNG_EXPORT(ordinal, type, name, (args));
+ *
+ *       ordinal:    ordinal that is used while building
+ *                   *.def files. The ordinal value is only
+ *                   relevant when preprocessing png.h with
+ *                   the *.dfn files for building symbol table
+ *                   entries, and are removed by pngconf.h.
+ *       type:       return type of the function
+ *       name:       function name
+ *       args:       function arguments, with types
+ *
+ * When we wish to append attributes to a function prototype we use
+ * the PNG_EXPORTA() macro instead.
+ *
+ *   PNG_EXPORTA(ordinal, type, name, (args), attributes);
+ *
+ *       ordinal, type, name, and args: same as in PNG_EXPORT().
+ *       attributes: function attributes
+ */
+
+/* Returns the version number of the library */
+PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
+
+/* Tell lib we have already handled the first <num_bytes> magic bytes.
+ * Handling more than 8 bytes from the beginning of the file is an error.
+ */
+PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
+
+/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
+ * PNG file.  Returns zero if the supplied bytes match the 8-byte PNG
+ * signature, and non-zero otherwise.  Having num_to_check == 0 or
+ * start > 7 will always fail (ie return non-zero).
+ */
+PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start,
+    size_t num_to_check));
+
+/* Simple signature checking function.  This is the same as calling
+ * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
+ */
+#define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
+
+/* Allocate and initialize png_ptr struct for reading, and any other memory. */
+PNG_EXPORTA(4, png_structp, png_create_read_struct,
+    (png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn),
+    PNG_ALLOCATED);
+
+/* Allocate and initialize png_ptr struct for writing, and any other memory */
+PNG_EXPORTA(5, png_structp, png_create_write_struct,
+    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+    png_error_ptr warn_fn),
+    PNG_ALLOCATED);
+
+PNG_EXPORT(6, size_t, png_get_compression_buffer_size,
+    (png_const_structrp png_ptr));
+
+PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
+    size_t size));
+
+/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
+ * match up.
+ */
+#ifdef PNG_SETJMP_SUPPORTED
+/* This function returns the jmp_buf built in to *png_ptr.  It must be
+ * supplied with an appropriate 'longjmp' function to use on that jmp_buf
+ * unless the default error function is overridden in which case NULL is
+ * acceptable.  The size of the jmp_buf is checked against the actual size
+ * allocated by the library - the call will return NULL on a mismatch
+ * indicating an ABI mismatch.
+ */
+PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
+    png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
+#  define png_jmpbuf(png_ptr) \
+      (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
+#else
+#  define png_jmpbuf(png_ptr) \
+      (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
+#endif
+/* This function should be used by libpng applications in place of
+ * longjmp(png_ptr->jmpbuf, val).  If longjmp_fn() has been set, it
+ * will use it; otherwise it will call PNG_ABORT().  This function was
+ * added in libpng-1.5.0.
+ */
+PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
+    PNG_NORETURN);
+
+#ifdef PNG_READ_SUPPORTED
+/* Reset the compression stream */
+PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
+#endif
+
+/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
+    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+    png_error_ptr warn_fn,
+    png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
+    PNG_ALLOCATED);
+PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
+    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+    png_error_ptr warn_fn,
+    png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
+    PNG_ALLOCATED);
+#endif
+
+/* Write the PNG file signature. */
+PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
+
+/* Write a PNG chunk - size, type, (optional) data, CRC. */
+PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
+    chunk_name, png_const_bytep data, size_t length));
+
+/* Write the start of a PNG chunk - length and chunk name. */
+PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
+    png_const_bytep chunk_name, png_uint_32 length));
+
+/* Write the data of a PNG chunk started with png_write_chunk_start(). */
+PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
+    png_const_bytep data, size_t length));
+
+/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
+PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
+
+/* Allocate and initialize the info structure */
+PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
+    PNG_ALLOCATED);
+
+/* DEPRECATED: this function allowed init structures to be created using the
+ * default allocation method (typically malloc).  Use is deprecated in 1.6.0 and
+ * the API will be removed in the future.
+ */
+PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
+    size_t png_info_struct_size), PNG_DEPRECATED);
+
+/* Writes all the PNG information before the image. */
+PNG_EXPORT(20, void, png_write_info_before_PLTE,
+    (png_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(21, void, png_write_info,
+    (png_structrp png_ptr, png_const_inforp info_ptr));
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the information before the actual image data. */
+PNG_EXPORT(22, void, png_read_info,
+    (png_structrp png_ptr, png_inforp info_ptr));
+#endif
+
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+   /* Convert to a US string format: there is no localization support in this
+    * routine.  The original implementation used a 29 character buffer in
+    * png_struct, this will be removed in future versions.
+    */
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
+PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
+    png_const_timep ptime),PNG_DEPRECATED);
+#endif
+PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
+    png_const_timep ptime));
+#endif
+
+#ifdef PNG_CONVERT_tIME_SUPPORTED
+/* Convert from a struct tm to png_time */
+PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
+    const struct tm * ttime));
+
+/* Convert from time_t to png_time.  Uses gmtime() */
+PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
+#endif /* CONVERT_tIME */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
+PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
+PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
+PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
+PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
+ * of a tRNS chunk if present.
+ */
+PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Use blue, green, red order for pixels. */
+PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* Expand the grayscale to 24-bit RGB if necessary. */
+PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* Reduce RGB to grayscale. */
+#define PNG_ERROR_ACTION_NONE  1
+#define PNG_ERROR_ACTION_WARN  2
+#define PNG_ERROR_ACTION_ERROR 3
+#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
+
+PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
+    int error_action, double red, double green))
+PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
+    int error_action, png_fixed_point red, png_fixed_point green))
+
+PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
+    png_ptr));
+#endif
+
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
+    png_colorp palette));
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* How the alpha channel is interpreted - this affects how the color channels
+ * of a PNG file are returned to the calling application when an alpha channel,
+ * or a tRNS chunk in a palette file, is present.
+ *
+ * This has no effect on the way pixels are written into a PNG output
+ * datastream. The color samples in a PNG datastream are never premultiplied
+ * with the alpha samples.
+ *
+ * The default is to return data according to the PNG specification: the alpha
+ * channel is a linear measure of the contribution of the pixel to the
+ * corresponding composited pixel, and the color channels are unassociated
+ * (not premultiplied).  The gamma encoded color channels must be scaled
+ * according to the contribution and to do this it is necessary to undo
+ * the encoding, scale the color values, perform the composition and re-encode
+ * the values.  This is the 'PNG' mode.
+ *
+ * The alternative is to 'associate' the alpha with the color information by
+ * storing color channel values that have been scaled by the alpha.
+ * image.  These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+ * (the latter being the two common names for associated alpha color channels).
+ *
+ * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
+ * value is equal to the maximum value.
+ *
+ * The final choice is to gamma encode the alpha channel as well.  This is
+ * broken because, in practice, no implementation that uses this choice
+ * correctly undoes the encoding before handling alpha composition.  Use this
+ * choice only if other serious errors in the software or hardware you use
+ * mandate it; the typical serious error is for dark halos to appear around
+ * opaque areas of the composited PNG image because of arithmetic overflow.
+ *
+ * The API function png_set_alpha_mode specifies which of these choices to use
+ * with an enumerated 'mode' value and the gamma of the required output:
+ */
+#define PNG_ALPHA_PNG           0 /* according to the PNG standard */
+#define PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
+#define PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
+#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
+#define PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
+#define PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
+
+PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
+    double output_gamma))
+PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
+    int mode, png_fixed_point output_gamma))
+#endif
+
+#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+/* The output_gamma value is a screen gamma in libpng terminology: it expresses
+ * how to decode the output values, not how they are encoded.
+ */
+#define PNG_DEFAULT_sRGB -1       /* sRGB gamma and color space */
+#define PNG_GAMMA_MAC_18 -2       /* Old Mac '1.8' gamma and color space */
+#define PNG_GAMMA_sRGB   220000   /* Television standards--matches sRGB gamma */
+#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
+#endif
+
+/* The following are examples of calls to png_set_alpha_mode to achieve the
+ * required overall gamma correction and, where necessary, alpha
+ * premultiplication.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ *    This is the default libpng handling of the alpha channel - it is not
+ *    pre-multiplied into the color components.  In addition the call states
+ *    that the output is for a sRGB system and causes all PNG files without gAMA
+ *    chunks to be assumed to be encoded using sRGB.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ *    In this case the output is assumed to be something like an sRGB conformant
+ *    display preceded by a power-law lookup table of power 1.45.  This is how
+ *    early Mac systems behaved.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+ *    This is the classic Jim Blinn approach and will work in academic
+ *    environments where everything is done by the book.  It has the shortcoming
+ *    of assuming that input PNG data with no gamma information is linear - this
+ *    is unlikely to be correct unless the PNG files where generated locally.
+ *    Most of the time the output precision will be so low as to show
+ *    significant banding in dark areas of the image.
+ *
+ * png_set_expand_16(pp);
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+ *    This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
+ *    are assumed to have the sRGB encoding if not marked with a gamma value and
+ *    the output is always 16 bits per component.  This permits accurate scaling
+ *    and processing of the data.  If you know that your input PNG files were
+ *    generated locally you might need to replace PNG_DEFAULT_sRGB with the
+ *    correct value for your system.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+ *    If you just need to composite the PNG image onto an existing background
+ *    and if you control the code that does this you can use the optimization
+ *    setting.  In this case you just copy completely opaque pixels to the
+ *    output.  For pixels that are not completely transparent (you just skip
+ *    those) you do the composition math using png_composite or png_composite_16
+ *    below then encode the resultant 8-bit or 16-bit values to match the output
+ *    encoding.
+ *
+ * Other cases
+ *    If neither the PNG nor the standard linear encoding work for you because
+ *    of the software or hardware you use then you have a big problem.  The PNG
+ *    case will probably result in halos around the image.  The linear encoding
+ *    will probably result in a washed out, too bright, image (it's actually too
+ *    contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
+ *    substantially reduce the halos.  Alternatively try:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+ *    This option will also reduce the halos, but there will be slight dark
+ *    halos round the opaque parts of the image where the background is light.
+ *    In the OPTIMIZED mode the halos will be light halos where the background
+ *    is dark.  Take your pick - the halos are unavoidable unless you can get
+ *    your hardware/software fixed!  (The OPTIMIZED approach is slightly
+ *    faster.)
+ *
+ * When the default gamma of PNG files doesn't match the output gamma.
+ *    If you have PNG files with no gamma information png_set_alpha_mode allows
+ *    you to provide a default gamma, but it also sets the output gamma to the
+ *    matching value.  If you know your PNG files have a gamma that doesn't
+ *    match the output you can take advantage of the fact that
+ *    png_set_alpha_mode always sets the output gamma but only sets the PNG
+ *    default if it is not already set:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ *    The first call sets both the default and the output gamma values, the
+ *    second call overrides the output gamma without changing the default.  This
+ *    is easier than achieving the same effect with png_set_gamma.  You must use
+ *    PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+ *    fire if more than one call to png_set_alpha_mode and png_set_background is
+ *    made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+ *    are ignored.
+ */
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+/* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
+PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
+    int flags));
+/* The values of the PNG_FILLER_ defines should NOT be changed */
+#  define PNG_FILLER_BEFORE 0
+#  define PNG_FILLER_AFTER 1
+/* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
+PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
+    png_uint_32 filler, int flags));
+#endif /* READ_FILLER || WRITE_FILLER */
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Swap bytes in 16-bit depth files. */
+PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
+PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
+    defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+/* Swap packing order of pixels in bytes. */
+PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+/* Converts files to legal bit depths. */
+PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
+    true_bits));
+#endif
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+    defined(PNG_WRITE_INTERLACING_SUPPORTED)
+/* Have the code handle the interlacing.  Returns the number of passes.
+ * MUST be called before png_read_update_info or png_start_read_image,
+ * otherwise it will not have the desired effect.  Note that it is still
+ * necessary to call png_read_row or png_read_rows png_get_image_height
+ * times for each pass.
+*/
+PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+/* Invert monochrome files */
+PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* Handle alpha and tRNS by replacing with a background color.  Prior to
+ * libpng-1.5.4 this API must not be called before the PNG file header has been
+ * read.  Doing so will result in unexpected behavior and possible warnings or
+ * errors if the PNG file contains a bKGD chunk.
+ */
+PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
+    png_const_color_16p background_color, int background_gamma_code,
+    int need_expand, double background_gamma))
+PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
+    png_const_color_16p background_color, int background_gamma_code,
+    int need_expand, png_fixed_point background_gamma))
+#endif
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+#  define PNG_BACKGROUND_GAMMA_UNKNOWN 0
+#  define PNG_BACKGROUND_GAMMA_SCREEN  1
+#  define PNG_BACKGROUND_GAMMA_FILE    2
+#  define PNG_BACKGROUND_GAMMA_UNIQUE  3
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+/* Scale a 16-bit depth file down to 8-bit, accurately. */
+PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+#define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */
+/* Strip the second byte of information from a 16-bit depth file. */
+PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* Turn on quantizing, and reduce the palette to the number of colors
+ * available.
+ */
+PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
+    png_colorp palette, int num_palette, int maximum_colors,
+    png_const_uint_16p histogram, int full_quantize));
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* The threshold on gamma processing is configurable but hard-wired into the
+ * library.  The following is the floating point variant.
+ */
+#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
+
+/* Handle gamma correction. Screen_gamma=(display_exponent).
+ * NOTE: this API simply sets the screen and file gamma values. It will
+ * therefore override the value for gamma in a PNG file if it is called after
+ * the file header has been read - use with care  - call before reading the PNG
+ * file for best results!
+ *
+ * These routines accept the same gamma values as png_set_alpha_mode (described
+ * above).  The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
+ * API (floating point or fixed.)  Notice, however, that the 'file_gamma' value
+ * is the inverse of a 'screen gamma' value.
+ */
+PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
+    double screen_gamma, double override_file_gamma))
+PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
+    png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
+#endif
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+/* Set how many lines between output flushes - 0 for no flushing */
+PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
+/* Flush the current PNG output buffer */
+PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
+#endif
+
+/* Optional update palette with requested transformations */
+PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
+
+/* Optional call to update the users info structure */
+PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
+    png_inforp info_ptr));
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read one or more rows of image data. */
+PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
+    png_bytepp display_row, png_uint_32 num_rows));
+#endif
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read a row of data. */
+PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
+    png_bytep display_row));
+#endif
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the whole image into memory at once. */
+PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
+#endif
+
+/* Write a row of image data */
+PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
+    png_const_bytep row));
+
+/* Write a few rows of image data: (*row) is not written; however, the type
+ * is declared as writeable to maintain compatibility with previous versions
+ * of libpng and to allow the 'display_row' array from read_rows to be passed
+ * unchanged to write_rows.
+ */
+PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
+    png_uint_32 num_rows));
+
+/* Write the image data */
+PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
+
+/* Write the end of the PNG file. */
+PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
+    png_inforp info_ptr));
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the end of the PNG file. */
+PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
+#endif
+
+/* Free any memory associated with the png_info_struct */
+PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
+    png_infopp info_ptr_ptr));
+
+/* Free any memory associated with the png_struct and the png_info_structs */
+PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
+    png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
+
+/* Free any memory associated with the png_struct and the png_info_structs */
+PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
+    png_infopp info_ptr_ptr));
+
+/* Set the libpng method of handling chunk CRC errors */
+PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
+    int ancil_action));
+
+/* Values for png_set_crc_action() say how to handle CRC errors in
+ * ancillary and critical chunks, and whether to use the data contained
+ * therein.  Note that it is impossible to "discard" data in a critical
+ * chunk.  For versions prior to 0.90, the action was always error/quit,
+ * whereas in version 0.90 and later, the action for CRC errors in ancillary
+ * chunks is warn/discard.  These values should NOT be changed.
+ *
+ *      value                       action:critical     action:ancillary
+ */
+#define PNG_CRC_DEFAULT       0  /* error/quit          warn/discard data */
+#define PNG_CRC_ERROR_QUIT    1  /* error/quit          error/quit        */
+#define PNG_CRC_WARN_DISCARD  2  /* (INVALID)           warn/discard data */
+#define PNG_CRC_WARN_USE      3  /* warn/use data       warn/use data     */
+#define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */
+#define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */
+
+#ifdef PNG_WRITE_SUPPORTED
+/* These functions give the user control over the scan-line filtering in
+ * libpng and the compression methods used by zlib.  These functions are
+ * mainly useful for testing, as the defaults should work with most users.
+ * Those users who are tight on memory or want faster performance at the
+ * expense of compression can modify them.  See the compression library
+ * header file (zlib.h) for an explination of the compression functions.
+ */
+
+/* Set the filtering method(s) used by libpng.  Currently, the only valid
+ * value for "method" is 0.
+ */
+PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
+    int filters));
+#endif /* WRITE */
+
+/* Flags for png_set_filter() to say which filters to use.  The flags
+ * are chosen so that they don't conflict with real filter types
+ * below, in case they are supplied instead of the #defined constants.
+ * These values should NOT be changed.
+ */
+#define PNG_NO_FILTERS     0x00
+#define PNG_FILTER_NONE    0x08
+#define PNG_FILTER_SUB     0x10
+#define PNG_FILTER_UP      0x20
+#define PNG_FILTER_AVG     0x40
+#define PNG_FILTER_PAETH   0x80
+#define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP)
+#define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH)
+
+/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
+ * These defines should NOT be changed.
+ */
+#define PNG_FILTER_VALUE_NONE  0
+#define PNG_FILTER_VALUE_SUB   1
+#define PNG_FILTER_VALUE_UP    2
+#define PNG_FILTER_VALUE_AVG   3
+#define PNG_FILTER_VALUE_PAETH 4
+#define PNG_FILTER_VALUE_LAST  5
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
+PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
+    int heuristic_method, int num_weights, png_const_doublep filter_weights,
+    png_const_doublep filter_costs))
+PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
+    (png_structrp png_ptr, int heuristic_method, int num_weights,
+    png_const_fixed_point_p filter_weights,
+    png_const_fixed_point_p filter_costs))
+#endif /* WRITE_WEIGHTED_FILTER */
+
+/* The following are no longer used and will be removed from libpng-1.7: */
+#define PNG_FILTER_HEURISTIC_DEFAULT    0  /* Currently "UNWEIGHTED" */
+#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1  /* Used by libpng < 0.95 */
+#define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
+#define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */
+
+/* Set the library compression level.  Currently, valid values range from
+ * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
+ * (0 - no compression, 9 - "maximal" compression).  Note that tests have
+ * shown that zlib compression levels 3-6 usually perform as well as level 9
+ * for PNG images, and do considerably fewer caclulations.  In the future,
+ * these values may not correspond directly to the zlib compression levels.
+ */
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
+    int level));
+
+PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
+    int mem_level));
+
+PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
+    int strategy));
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
+    int window_bits));
+
+PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
+    int method));
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+/* Also set zlib parameters for compressing non-IDAT chunks */
+PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
+    int level));
+
+PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
+    int mem_level));
+
+PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
+    int strategy));
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+PNG_EXPORT(225, void, png_set_text_compression_window_bits,
+    (png_structrp png_ptr, int window_bits));
+
+PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
+    int method));
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+#endif /* WRITE */
+
+/* These next functions are called for input/output, memory, and error
+ * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
+ * and call standard C I/O routines such as fread(), fwrite(), and
+ * fprintf().  These functions can be made to use other I/O routines
+ * at run time for those applications that need to handle I/O in a
+ * different manner by calling png_set_???_fn().  See libpng-manual.txt for
+ * more information.
+ */
+
+#ifdef PNG_STDIO_SUPPORTED
+/* Initialize the input/output for the PNG file to the default functions. */
+PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
+#endif
+
+/* Replace the (error and abort), and warning functions with user
+ * supplied functions.  If no messages are to be printed you must still
+ * write and use replacement functions. The replacement error_fn should
+ * still do a longjmp to the last setjmp location if you are using this
+ * method of error handling.  If error_fn or warning_fn is NULL, the
+ * default function will be used.
+ */
+
+PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
+    png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
+
+/* Return the user pointer associated with the error functions */
+PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
+
+/* Replace the default data output functions with a user supplied one(s).
+ * If buffered output is not used, then output_flush_fn can be set to NULL.
+ * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
+ * output_flush_fn will be ignored (and thus can be NULL).
+ * It is probably a mistake to use NULL for output_flush_fn if
+ * write_data_fn is not also NULL unless you have built libpng with
+ * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
+ * default flush function, which uses the standard *FILE structure, will
+ * be used.
+ */
+PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
+    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
+
+/* Replace the default data input function with a user supplied one. */
+PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
+    png_rw_ptr read_data_fn));
+
+/* Return the user pointer associated with the I/O functions */
+PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
+
+PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
+    png_read_status_ptr read_row_fn));
+
+PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
+    png_write_status_ptr write_row_fn));
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* Replace the default memory allocation functions with user supplied one(s). */
+PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
+    png_malloc_ptr malloc_fn, png_free_ptr free_fn));
+/* Return the user pointer associated with the memory functions */
+PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
+    png_user_transform_ptr read_user_transform_fn));
+#endif
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
+    png_user_transform_ptr write_user_transform_fn));
+#endif
+
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
+    png_voidp user_transform_ptr, int user_transform_depth,
+    int user_transform_channels));
+/* Return the user pointer associated with the user transform functions */
+PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
+    (png_const_structrp png_ptr));
+#endif
+
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+/* Return information about the row currently being processed.  Note that these
+ * APIs do not fail but will return unexpected results if called outside a user
+ * transform callback.  Also note that when transforming an interlaced image the
+ * row number is the row number within the sub-image of the interlace pass, so
+ * the value will increase to the height of the sub-image (not the full image)
+ * then reset to 0 for the next pass.
+ *
+ * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+ * find the output pixel (x,y) given an interlaced sub-image pixel
+ * (row,col,pass).  (See below for these macros.)
+ */
+PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
+PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
+#endif
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+/* This callback is called only for *unknown* chunks.  If
+ * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
+ * chunks to be treated as unknown, however in this case the callback must do
+ * any processing required by the chunk (e.g. by calling the appropriate
+ * png_set_ APIs.)
+ *
+ * There is no write support - on write, by default, all the chunks in the
+ * 'unknown' list are written in the specified position.
+ *
+ * The integer return from the callback function is interpreted thus:
+ *
+ * negative: An error occurred; png_chunk_error will be called.
+ *     zero: The chunk was not handled, the chunk will be saved. A critical
+ *           chunk will cause an error at this point unless it is to be saved.
+ * positive: The chunk was handled, libpng will ignore/discard it.
+ *
+ * See "INTERACTION WITH USER CHUNK CALLBACKS" below for important notes about
+ * how this behavior will change in libpng 1.7
+ */
+PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
+    png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
+#endif
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+/* Sets the function callbacks for the push reader, and a pointer to a
+ * user-defined structure available to the callback functions.
+ */
+PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
+    png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
+    png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
+
+/* Returns the user pointer associated with the push read functions */
+PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
+    (png_const_structrp png_ptr));
+
+/* Function to be called when data becomes available */
+PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
+    png_inforp info_ptr, png_bytep buffer, size_t buffer_size));
+
+/* A function which may be called *only* within png_process_data to stop the
+ * processing of any more data.  The function returns the number of bytes
+ * remaining, excluding any that libpng has cached internally.  A subsequent
+ * call to png_process_data must supply these bytes again.  If the argument
+ * 'save' is set to true the routine will first save all the pending data and
+ * will always return 0.
+ */
+PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save));
+
+/* A function which may be called *only* outside (after) a call to
+ * png_process_data.  It returns the number of bytes of data to skip in the
+ * input.  Normally it will return 0, but if it returns a non-zero value the
+ * application must skip than number of bytes of input data and pass the
+ * following data to the next call to png_process_data.
+ */
+PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
+
+/* Function that combines rows.  'new_row' is a flag that should come from
+ * the callback and be non-NULL if anything needs to be done; the library
+ * stores its own version of the new data internally and ignores the passed
+ * in value.
+ */
+PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
+    png_bytep old_row, png_const_bytep new_row));
+#endif /* PROGRESSIVE_READ */
+
+PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED);
+/* Added at libpng version 1.4.0 */
+PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED);
+
+/* Added at libpng version 1.2.4 */
+PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED);
+
+/* Frees a pointer allocated by png_malloc() */
+PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
+
+/* Free data that was allocated internally */
+PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 free_me, int num));
+
+/* Reassign responsibility for freeing existing data, whether allocated
+ * by libpng or by the application; this works on the png_info structure passed
+ * in, it does not change the state for other png_info structures.
+ *
+ * It is unlikely that this function works correctly as of 1.6.0 and using it
+ * may result either in memory leaks or double free of allocated data.
+ */
+PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int freer, png_uint_32 mask));
+
+/* Assignments for png_data_freer */
+#define PNG_DESTROY_WILL_FREE_DATA 1
+#define PNG_SET_WILL_FREE_DATA 1
+#define PNG_USER_WILL_FREE_DATA 2
+/* Flags for png_ptr->free_me and info_ptr->free_me */
+#define PNG_FREE_HIST 0x0008U
+#define PNG_FREE_ICCP 0x0010U
+#define PNG_FREE_SPLT 0x0020U
+#define PNG_FREE_ROWS 0x0040U
+#define PNG_FREE_PCAL 0x0080U
+#define PNG_FREE_SCAL 0x0100U
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#  define PNG_FREE_UNKN 0x0200U
+#endif
+/*      PNG_FREE_LIST 0x0400U   removed in 1.6.0 because it is ignored */
+#define PNG_FREE_PLTE 0x1000U
+#define PNG_FREE_TRNS 0x2000U
+#define PNG_FREE_TEXT 0x4000U
+#define PNG_FREE_EXIF 0x8000U /* Added at libpng-1.6.31 */
+#define PNG_FREE_ALL  0xffffU
+#define PNG_FREE_MUL  0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
+
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
+PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
+    png_voidp ptr), PNG_DEPRECATED);
+#endif
+
+#ifdef PNG_ERROR_TEXT_SUPPORTED
+/* Fatal error in PNG image of libpng - can't continue */
+PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
+    png_const_charp error_message), PNG_NORETURN);
+
+/* The same, but the chunk name is prepended to the error string. */
+PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
+    png_const_charp error_message), PNG_NORETURN);
+
+#else
+/* Fatal error in PNG image of libpng - can't continue */
+PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
+#  define png_error(s1,s2) png_err(s1)
+#  define png_chunk_error(s1,s2) png_err(s1)
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* Non-fatal error in libpng.  Can continue, but may have a problem. */
+PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
+    png_const_charp warning_message));
+
+/* Non-fatal error in libpng, chunk name is prepended to message. */
+PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
+    png_const_charp warning_message));
+#else
+#  define png_warning(s1,s2) ((void)(s1))
+#  define png_chunk_warning(s1,s2) ((void)(s1))
+#endif
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+/* Benign error in libpng.  Can continue, but may have a problem.
+ * User can choose whether to handle as a fatal error or as a warning. */
+PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
+    png_const_charp warning_message));
+
+#ifdef PNG_READ_SUPPORTED
+/* Same, chunk name is prepended to message (only during read) */
+PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
+    png_const_charp warning_message));
+#endif
+
+PNG_EXPORT(109, void, png_set_benign_errors,
+    (png_structrp png_ptr, int allowed));
+#else
+#  ifdef PNG_ALLOW_BENIGN_ERRORS
+#    define png_benign_error png_warning
+#    define png_chunk_benign_error png_chunk_warning
+#  else
+#    define png_benign_error png_error
+#    define png_chunk_benign_error png_chunk_error
+#  endif
+#endif
+
+/* The png_set_<chunk> functions are for storing values in the png_info_struct.
+ * Similarly, the png_get_<chunk> calls are used to read values from the
+ * png_info_struct, either storing the parameters in the passed variables, or
+ * setting pointers into the png_info_struct where the data is stored.  The
+ * png_get_<chunk> functions return a non-zero value if the data was available
+ * in info_ptr, or return zero and do not change any of the parameters if the
+ * data was not available.
+ *
+ * These functions should be used instead of directly accessing png_info
+ * to avoid problems with future changes in the size and internal layout of
+ * png_info_struct.
+ */
+/* Returns "flag" if chunk data is valid in info_ptr. */
+PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 flag));
+
+/* Returns number of bytes needed to hold a transformed row. */
+PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+/* Returns row_pointers, which is an array of pointers to scanlines that was
+ * returned from png_read_png().
+ */
+PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Set row_pointers, which is an array of pointers to scanlines for use
+ * by png_write_png().
+ */
+PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_bytepp row_pointers));
+#endif
+
+/* Returns number of color channels in image. */
+PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+/* Returns image width in pixels. */
+PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image height in pixels. */
+PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image bit_depth. */
+PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image color_type. */
+PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image filter_type. */
+PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image interlace_type. */
+PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image compression_type. */
+PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image resolution in pixels per meter, from pHYs chunk data. */
+PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+/* Returns pixel aspect ratio, computed from pHYs chunk data.  */
+PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+
+/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
+PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+#endif /* EASY_ACCESS */
+
+#ifdef PNG_READ_SUPPORTED
+/* Returns pointer to signature string read from PNG header */
+PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+#endif
+
+#ifdef PNG_bKGD_SUPPORTED
+PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_color_16p *background));
+#endif
+
+#ifdef PNG_bKGD_SUPPORTED
+PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_color_16p background));
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
+    double *red_y, double *green_x, double *green_y, double *blue_x,
+    double *blue_y))
+PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
+    double *green_X, double *green_Y, double *green_Z, double *blue_X,
+    double *blue_Y, double *blue_Z))
+PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *int_white_x, png_fixed_point *int_white_y,
+    png_fixed_point *int_red_x, png_fixed_point *int_red_y,
+    png_fixed_point *int_green_x, png_fixed_point *int_green_y,
+    png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
+PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
+    png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
+    png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
+    png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
+    png_fixed_point *int_blue_Z))
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
+    png_inforp info_ptr,
+    double white_x, double white_y, double red_x, double red_y, double green_x,
+    double green_y, double blue_x, double blue_y))
+PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
+    png_inforp info_ptr, double red_X, double red_Y, double red_Z,
+    double green_X, double green_Y, double green_Z, double blue_X,
+    double blue_Y, double blue_Z))
+PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_fixed_point int_white_x,
+    png_fixed_point int_white_y, png_fixed_point int_red_x,
+    png_fixed_point int_red_y, png_fixed_point int_green_x,
+    png_fixed_point int_green_y, png_fixed_point int_blue_x,
+    png_fixed_point int_blue_y))
+PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
+    png_fixed_point int_red_Z, png_fixed_point int_green_X,
+    png_fixed_point int_green_Y, png_fixed_point int_green_Z,
+    png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
+    png_fixed_point int_blue_Z))
+#endif
+
+#ifdef PNG_eXIf_SUPPORTED
+PNG_EXPORT(246, png_uint_32, png_get_eXIf, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_bytep *exif));
+PNG_EXPORT(247, void, png_set_eXIf, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_bytep exif));
+
+PNG_EXPORT(248, png_uint_32, png_get_eXIf_1, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 *num_exif, png_bytep *exif));
+PNG_EXPORT(249, void, png_set_eXIf_1, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 num_exif, png_bytep exif));
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, double *file_gamma))
+PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *int_file_gamma))
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
+    png_inforp info_ptr, double file_gamma))
+PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_fixed_point int_file_gamma))
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_16p *hist));
+PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_uint_16p hist));
+#endif
+
+PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
+    int *bit_depth, int *color_type, int *interlace_method,
+    int *compression_method, int *filter_method));
+
+PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
+    int color_type, int interlace_method, int compression_method,
+    int filter_method));
+
+#ifdef PNG_oFFs_SUPPORTED
+PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
+   png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
+   int *unit_type));
+#endif
+
+#ifdef PNG_oFFs_SUPPORTED
+PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
+    int unit_type));
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
+    png_int_32 *X1, int *type, int *nparams, png_charp *units,
+    png_charpp *params));
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
+    int type, int nparams, png_const_charp units, png_charpp params));
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
+    int *unit_type));
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
+#endif
+
+PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
+   png_inforp info_ptr, png_colorp *palette, int *num_palette));
+
+PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
+    png_inforp info_ptr, png_const_colorp palette, int num_palette));
+
+#ifdef PNG_sBIT_SUPPORTED
+PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_color_8p *sig_bit));
+#endif
+
+#ifdef PNG_sBIT_SUPPORTED
+PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_color_8p sig_bit));
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, int *file_srgb_intent));
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int srgb_intent));
+PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int srgb_intent));
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_charpp name, int *compression_type,
+    png_bytepp profile, png_uint_32 *proflen));
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_charp name, int compression_type,
+    png_const_bytep profile, png_uint_32 proflen));
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_sPLT_tpp entries));
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+/* png_get_text also returns the number of text chunks in *num_text */
+PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_textp *text_ptr, int *num_text));
+#endif
+
+/* Note while png_set_text() will accept a structure whose text,
+ * language, and  translated keywords are NULL pointers, the structure
+ * returned by png_get_text will always contain regular
+ * zero-terminated C strings.  They might be empty strings but
+ * they will never be NULL pointers.
+ */
+
+#ifdef PNG_TEXT_SUPPORTED
+PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_textp text_ptr, int num_text));
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_timep *mod_time));
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_timep mod_time));
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
+    png_color_16p *trans_color));
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
+    png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
+    png_const_color_16p trans_color));
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, int *unit, double *width, double *height))
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+   defined(PNG_FLOATING_POINT_SUPPORTED)
+/* NOTE: this API is currently implemented using floating point arithmetic,
+ * consequently it can only be used on systems with floating point support.
+ * In any case the range of values supported by png_fixed_point is small and it
+ * is highly recommended that png_get_sCAL_s be used instead.
+ */
+PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
+    png_fixed_point *width, png_fixed_point *height))
+#endif
+PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
+    png_charpp swidth, png_charpp sheight));
+
+PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int unit, double width, double height))
+PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
+   png_inforp info_ptr, int unit, png_fixed_point width,
+   png_fixed_point height))
+PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int unit,
+    png_const_charp swidth, png_const_charp sheight));
+#endif /* sCAL */
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+/* Provide the default handling for all unknown chunks or, optionally, for
+ * specific unknown chunks.
+ *
+ * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
+ * ignored and the default was used, the per-chunk setting only had an effect on
+ * write.  If you wish to have chunk-specific handling on read in code that must
+ * work on earlier versions you must use a user chunk callback to specify the
+ * desired handling (keep or discard.)
+ *
+ * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below.  The
+ * parameter is interpreted as follows:
+ *
+ * READ:
+ *    PNG_HANDLE_CHUNK_AS_DEFAULT:
+ *       Known chunks: do normal libpng processing, do not keep the chunk (but
+ *          see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+ *       Unknown chunks: for a specific chunk use the global default, when used
+ *          as the default discard the chunk data.
+ *    PNG_HANDLE_CHUNK_NEVER:
+ *       Discard the chunk data.
+ *    PNG_HANDLE_CHUNK_IF_SAFE:
+ *       Keep the chunk data if the chunk is not critical else raise a chunk
+ *       error.
+ *    PNG_HANDLE_CHUNK_ALWAYS:
+ *       Keep the chunk data.
+ *
+ * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
+ * below.  Notice that specifying "AS_DEFAULT" as a global default is equivalent
+ * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
+ * it simply resets the behavior to the libpng default.
+ *
+ * INTERACTION WITH USER CHUNK CALLBACKS:
+ * The per-chunk handling is always used when there is a png_user_chunk_ptr
+ * callback and the callback returns 0; the chunk is then always stored *unless*
+ * it is critical and the per-chunk setting is other than ALWAYS.  Notice that
+ * the global default is *not* used in this case.  (In effect the per-chunk
+ * value is incremented to at least IF_SAFE.)
+ *
+ * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
+ * per-chunk defaults will be honored.  If you want to preserve the current
+ * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
+ * as the default - if you don't do this libpng 1.6 will issue a warning.
+ *
+ * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
+ * earlier simply return '1' (handled).
+ *
+ * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
+ *    If this is *not* set known chunks will always be handled by libpng and
+ *    will never be stored in the unknown chunk list.  Known chunks listed to
+ *    png_set_keep_unknown_chunks will have no effect.  If it is set then known
+ *    chunks listed with a keep other than AS_DEFAULT will *never* be processed
+ *    by libpng, in addition critical chunks must either be processed by the
+ *    callback or saved.
+ *
+ *    The IHDR and IEND chunks must not be listed.  Because this turns off the
+ *    default handling for chunks that would otherwise be recognized the
+ *    behavior of libpng transformations may well become incorrect!
+ *
+ * WRITE:
+ *    When writing chunks the options only apply to the chunks specified by
+ *    png_set_unknown_chunks (below), libpng will *always* write known chunks
+ *    required by png_set_ calls and will always write the core critical chunks
+ *    (as required for PLTE).
+ *
+ *    Each chunk in the png_set_unknown_chunks list is looked up in the
+ *    png_set_keep_unknown_chunks list to find the keep setting, this is then
+ *    interpreted as follows:
+ *
+ *    PNG_HANDLE_CHUNK_AS_DEFAULT:
+ *       Write safe-to-copy chunks and write other chunks if the global
+ *       default is set to _ALWAYS, otherwise don't write this chunk.
+ *    PNG_HANDLE_CHUNK_NEVER:
+ *       Do not write the chunk.
+ *    PNG_HANDLE_CHUNK_IF_SAFE:
+ *       Write the chunk if it is safe-to-copy, otherwise do not write it.
+ *    PNG_HANDLE_CHUNK_ALWAYS:
+ *       Write the chunk.
+ *
+ * Note that the default behavior is effectively the opposite of the read case -
+ * in read unknown chunks are not stored by default, in write they are written
+ * by default.  Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
+ * - on write the safe-to-copy bit is checked, on read the critical bit is
+ * checked and on read if the chunk is critical an error will be raised.
+ *
+ * num_chunks:
+ * ===========
+ *    If num_chunks is positive, then the "keep" parameter specifies the manner
+ *    for handling only those chunks appearing in the chunk_list array,
+ *    otherwise the chunk list array is ignored.
+ *
+ *    If num_chunks is 0 the "keep" parameter specifies the default behavior for
+ *    unknown chunks, as described above.
+ *
+ *    If num_chunks is negative, then the "keep" parameter specifies the manner
+ *    for handling all unknown chunks plus all chunks recognized by libpng
+ *    except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
+ *    be processed by libpng.
+ */
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
+    int keep, png_const_bytep chunk_list, int num_chunks));
+#endif /* HANDLE_AS_UNKNOWN */
+
+/* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
+ * the result is therefore true (non-zero) if special handling is required,
+ * false for the default handling.
+ */
+PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
+    png_const_bytep chunk_name));
+#endif /* SET_UNKNOWN_CHUNKS */
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_unknown_chunkp unknowns,
+    int num_unknowns));
+   /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
+    * unknowns to the location currently stored in the png_struct.  This is
+    * invariably the wrong value on write.  To fix this call the following API
+    * for each chunk in the list with the correct location.  If you know your
+    * code won't be compiled on earlier versions you can rely on
+    * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
+    * the correct thing.
+    */
+
+PNG_EXPORT(175, void, png_set_unknown_chunk_location,
+    (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
+
+PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_unknown_chunkpp entries));
+#endif
+
+/* Png_free_data() will turn off the "valid" flag for anything it frees.
+ * If you need to turn it off for a chunk that your application has freed,
+ * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
+ */
+PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int mask));
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+/* The "params" pointer is currently not used and is for future expansion. */
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
+    int transforms, png_voidp params));
+#endif
+#ifdef PNG_WRITE_SUPPORTED
+PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
+    int transforms, png_voidp params));
+#endif
+#endif
+
+PNG_EXPORT(180, png_const_charp, png_get_copyright,
+    (png_const_structrp png_ptr));
+PNG_EXPORT(181, png_const_charp, png_get_header_ver,
+    (png_const_structrp png_ptr));
+PNG_EXPORT(182, png_const_charp, png_get_header_version,
+    (png_const_structrp png_ptr));
+PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
+    (png_const_structrp png_ptr));
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
+    png_uint_32 mng_features_permitted));
+#endif
+
+/* For use in png_set_keep_unknown, added to version 1.2.6 */
+#define PNG_HANDLE_CHUNK_AS_DEFAULT   0
+#define PNG_HANDLE_CHUNK_NEVER        1
+#define PNG_HANDLE_CHUNK_IF_SAFE      2
+#define PNG_HANDLE_CHUNK_ALWAYS       3
+#define PNG_HANDLE_CHUNK_LAST         4
+
+/* Strip the prepended error numbers ("#nnn ") from error and warning
+ * messages before passing them to the error or warning handler.
+ */
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
+    png_uint_32 strip_mode));
+#endif
+
+/* Added in libpng-1.2.6 */
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
+    png_uint_32 user_width_max, png_uint_32 user_height_max));
+PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
+    (png_const_structrp png_ptr));
+PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
+    (png_const_structrp png_ptr));
+/* Added in libpng-1.4.0 */
+PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
+    png_uint_32 user_chunk_cache_max));
+PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
+    (png_const_structrp png_ptr));
+/* Added in libpng-1.4.1 */
+PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
+    png_alloc_size_t user_chunk_cache_max));
+PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
+    (png_const_structrp png_ptr));
+#endif
+
+#if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
+PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+#endif
+
+PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr))
+#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
+PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+#endif
+
+#  ifdef PNG_pHYs_SUPPORTED
+PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
+    int *unit_type));
+#  endif /* pHYs */
+#endif  /* INCH_CONVERSIONS */
+
+/* Added in libpng-1.4.0 */
+#ifdef PNG_IO_STATE_SUPPORTED
+PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
+
+/* Removed from libpng 1.6; use png_get_io_chunk_type. */
+PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
+    PNG_DEPRECATED)
+
+PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
+    (png_const_structrp png_ptr));
+
+/* The flags returned by png_get_io_state() are the following: */
+#  define PNG_IO_NONE        0x0000   /* no I/O at this moment */
+#  define PNG_IO_READING     0x0001   /* currently reading */
+#  define PNG_IO_WRITING     0x0002   /* currently writing */
+#  define PNG_IO_SIGNATURE   0x0010   /* currently at the file signature */
+#  define PNG_IO_CHUNK_HDR   0x0020   /* currently at the chunk header */
+#  define PNG_IO_CHUNK_DATA  0x0040   /* currently at the chunk data */
+#  define PNG_IO_CHUNK_CRC   0x0080   /* currently at the chunk crc */
+#  define PNG_IO_MASK_OP     0x000f   /* current operation: reading/writing */
+#  define PNG_IO_MASK_LOC    0x00f0   /* current location: sig/hdr/data/crc */
+#endif /* IO_STATE */
+
+/* Interlace support.  The following macros are always defined so that if
+ * libpng interlace handling is turned off the macros may be used to handle
+ * interlaced images within the application.
+ */
+#define PNG_INTERLACE_ADAM7_PASSES 7
+
+/* Two macros to return the first row and first column of the original,
+ * full, image which appears in a given pass.  'pass' is in the range 0
+ * to 6 and the result is in the range 0 to 7.
+ */
+#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
+
+/* A macro to return the offset between pixels in the output row for a pair of
+ * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
+ * follows.  Note that ROW_OFFSET is the offset from one row to the next whereas
+ * COL_OFFSET is from one column to the next, within a row.
+ */
+#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
+#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
+
+/* Two macros to help evaluate the number of rows or columns in each
+ * pass.  This is expressed as a shift - effectively log2 of the number or
+ * rows or columns in each 8x8 tile of the original image.
+ */
+#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
+#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
+
+/* Hence two macros to determine the number of rows or columns in a given
+ * pass of an image given its height or width.  In fact these macros may
+ * return non-zero even though the sub-image is empty, because the other
+ * dimension may be empty for a small image.
+ */
+#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
+   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
+#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
+   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
+
+/* For the reader row callbacks (both progressive and sequential) it is
+ * necessary to find the row in the output image given a row in an interlaced
+ * image, so two more macros:
+ */
+#define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
+   (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
+#define PNG_COL_FROM_PASS_COL(x_in, pass) \
+   (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
+
+/* Two macros which return a boolean (0 or 1) saying whether the given row
+ * or column is in a particular pass.  These use a common utility macro that
+ * returns a mask for a given pass - the offset 'off' selects the row or
+ * column version.  The mask has the appropriate bit set for each column in
+ * the tile.
+ */
+#define PNG_PASS_MASK(pass,off) ( \
+   ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
+   ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
+
+#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
+   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
+#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
+   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
+
+#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
+/* With these routines we avoid an integer divide, which will be slower on
+ * most machines.  However, it does take more operations than the corresponding
+ * divide method, so it may be slower on a few RISC systems.  There are two
+ * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
+ *
+ * Note that the rounding factors are NOT supposed to be the same!  128 and
+ * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
+ * standard method.
+ *
+ * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
+ */
+
+ /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
+
+#  define png_composite(composite, fg, alpha, bg)        \
+   {                                                     \
+      png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
+          * (png_uint_16)(alpha)                         \
+          + (png_uint_16)(bg)*(png_uint_16)(255          \
+          - (png_uint_16)(alpha)) + 128);                \
+      (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); \
+   }
+
+#  define png_composite_16(composite, fg, alpha, bg)     \
+   {                                                     \
+      png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
+          * (png_uint_32)(alpha)                         \
+          + (png_uint_32)(bg)*(65535                     \
+          - (png_uint_32)(alpha)) + 32768);              \
+      (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); \
+   }
+
+#else  /* Standard method using integer division */
+
+#  define png_composite(composite, fg, alpha, bg)                      \
+   (composite) =                                                       \
+       (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) +  \
+       (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
+       127) / 255))
+
+#  define png_composite_16(composite, fg, alpha, bg)                       \
+   (composite) =                                                           \
+       (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
+       (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) +     \
+       32767) / 65535))
+#endif /* READ_COMPOSITE_NODIV */
+
+#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
+PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
+PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
+PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
+#endif
+
+PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
+    png_const_bytep buf));
+/* No png_get_int_16 -- may be added if there's a real need for it. */
+
+/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
+#endif
+#ifdef PNG_SAVE_INT_32_SUPPORTED
+PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
+#endif
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
+/* No png_save_int_16 -- may be added if there's a real need for it. */
+#endif
+
+#ifdef PNG_USE_READ_MACROS
+/* Inline macros to do direct reads of bytes from the input buffer.
+ * The png_get_int_32() routine assumes we are using two's complement
+ * format for negative values, which is almost certainly true.
+ */
+#  define PNG_get_uint_32(buf) \
+   (((png_uint_32)(*(buf)) << 24) + \
+    ((png_uint_32)(*((buf) + 1)) << 16) + \
+    ((png_uint_32)(*((buf) + 2)) << 8) + \
+    ((png_uint_32)(*((buf) + 3))))
+
+   /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+    * function) incorrectly returned a value of type png_uint_32.
+    */
+#  define PNG_get_uint_16(buf) \
+   ((png_uint_16) \
+    (((unsigned int)(*(buf)) << 8) + \
+    ((unsigned int)(*((buf) + 1)))))
+
+#  define PNG_get_int_32(buf) \
+   ((png_int_32)((*(buf) & 0x80) \
+    ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
+    : (png_int_32)png_get_uint_32(buf)))
+
+/* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
+ * but defining a macro name prefixed with PNG_PREFIX.
+ */
+#  ifndef PNG_PREFIX
+#    define png_get_uint_32(buf) PNG_get_uint_32(buf)
+#    define png_get_uint_16(buf) PNG_get_uint_16(buf)
+#    define png_get_int_32(buf)  PNG_get_int_32(buf)
+#  endif
+#else
+#  ifdef PNG_PREFIX
+   /* No macros; revert to the (redefined) function */
+#    define PNG_get_uint_32 (png_get_uint_32)
+#    define PNG_get_uint_16 (png_get_uint_16)
+#    define PNG_get_int_32  (png_get_int_32)
+#  endif
+#endif
+
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+PNG_EXPORT(242, void, png_set_check_for_invalid_index,
+    (png_structrp png_ptr, int allowed));
+#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
+    png_const_infop info_ptr));
+#  endif
+#endif /* CHECK_FOR_INVALID_INDEX */
+
+/*******************************************************************************
+ * Section 5: SIMPLIFIED API
+ *******************************************************************************
+ *
+ * Please read the documentation in libpng-manual.txt (TODO: write said
+ * documentation) if you don't understand what follows.
+ *
+ * The simplified API hides the details of both libpng and the PNG file format
+ * itself.  It allows PNG files to be read into a very limited number of
+ * in-memory bitmap formats or to be written from the same formats.  If these
+ * formats do not accommodate your needs then you can, and should, use the more
+ * sophisticated APIs above - these support a wide variety of in-memory formats
+ * and a wide variety of sophisticated transformations to those formats as well
+ * as a wide variety of APIs to manipulate ancillary information.
+ *
+ * To read a PNG file using the simplified API:
+ *
+ * 1) Declare a 'png_image' structure (see below) on the stack, set the
+ *    version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
+ *    (this is REQUIRED, your program may crash if you don't do it.)
+ * 2) Call the appropriate png_image_begin_read... function.
+ * 3) Set the png_image 'format' member to the required sample format.
+ * 4) Allocate a buffer for the image and, if required, the color-map.
+ * 5) Call png_image_finish_read to read the image and, if required, the
+ *    color-map into your buffers.
+ *
+ * There are no restrictions on the format of the PNG input itself; all valid
+ * color types, bit depths, and interlace methods are acceptable, and the
+ * input image is transformed as necessary to the requested in-memory format
+ * during the png_image_finish_read() step.  The only caveat is that if you
+ * request a color-mapped image from a PNG that is full-color or makes
+ * complex use of an alpha channel the transformation is extremely lossy and the
+ * result may look terrible.
+ *
+ * To write a PNG file using the simplified API:
+ *
+ * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
+ * 2) Initialize the members of the structure that describe the image, setting
+ *    the 'format' member to the format of the image samples.
+ * 3) Call the appropriate png_image_write... function with a pointer to the
+ *    image and, if necessary, the color-map to write the PNG data.
+ *
+ * png_image is a structure that describes the in-memory format of an image
+ * when it is being read or defines the in-memory format of an image that you
+ * need to write:
+ */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
+    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+
+#define PNG_IMAGE_VERSION 1
+
+typedef struct png_control *png_controlp;
+typedef struct
+{
+   png_controlp opaque;    /* Initialize to NULL, free with png_image_free */
+   png_uint_32  version;   /* Set to PNG_IMAGE_VERSION */
+   png_uint_32  width;     /* Image width in pixels (columns) */
+   png_uint_32  height;    /* Image height in pixels (rows) */
+   png_uint_32  format;    /* Image format as defined below */
+   png_uint_32  flags;     /* A bit mask containing informational flags */
+   png_uint_32  colormap_entries;
+                           /* Number of entries in the color-map */
+
+   /* In the event of an error or warning the following field will be set to a
+    * non-zero value and the 'message' field will contain a '\0' terminated
+    * string with the libpng error or warning message.  If both warnings and
+    * an error were encountered, only the error is recorded.  If there
+    * are multiple warnings, only the first one is recorded.
+    *
+    * The upper 30 bits of this value are reserved, the low two bits contain
+    * a value as follows:
+    */
+#  define PNG_IMAGE_WARNING 1
+#  define PNG_IMAGE_ERROR 2
+   /*
+    * The result is a two-bit code such that a value more than 1 indicates
+    * a failure in the API just called:
+    *
+    *    0 - no warning or error
+    *    1 - warning
+    *    2 - error
+    *    3 - error preceded by warning
+    */
+#  define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
+
+   png_uint_32  warning_or_error;
+
+   char         message[64];
+} png_image, *png_imagep;
+
+/* The samples of the image have one to four channels whose components have
+ * original values in the range 0 to 1.0:
+ *
+ * 1: A single gray or luminance channel (G).
+ * 2: A gray/luminance channel and an alpha channel (GA).
+ * 3: Three red, green, blue color channels (RGB).
+ * 4: Three color channels and an alpha channel (RGBA).
+ *
+ * The components are encoded in one of two ways:
+ *
+ * a) As a small integer, value 0..255, contained in a single byte.  For the
+ * alpha channel the original value is simply value/255.  For the color or
+ * luminance channels the value is encoded according to the sRGB specification
+ * and matches the 8-bit format expected by typical display devices.
+ *
+ * The color/gray channels are not scaled (pre-multiplied) by the alpha
+ * channel and are suitable for passing to color management software.
+ *
+ * b) As a value in the range 0..65535, contained in a 2-byte integer.  All
+ * channels can be converted to the original value by dividing by 65535; all
+ * channels are linear.  Color channels use the RGB encoding (RGB end-points) of
+ * the sRGB specification.  This encoding is identified by the
+ * PNG_FORMAT_FLAG_LINEAR flag below.
+ *
+ * When the simplified API needs to convert between sRGB and linear colorspaces,
+ * the actual sRGB transfer curve defined in the sRGB specification (see the
+ * article at <https://en.wikipedia.org/wiki/SRGB>) is used, not the gamma=1/2.2
+ * approximation used elsewhere in libpng.
+ *
+ * When an alpha channel is present it is expected to denote pixel coverage
+ * of the color or luminance channels and is returned as an associated alpha
+ * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
+ * value.
+ *
+ * The samples are either contained directly in the image data, between 1 and 8
+ * bytes per pixel according to the encoding, or are held in a color-map indexed
+ * by bytes in the image data.  In the case of a color-map the color-map entries
+ * are individual samples, encoded as above, and the image data has one byte per
+ * pixel to select the relevant sample from the color-map.
+ */
+
+/* PNG_FORMAT_*
+ *
+ * #defines to be used in png_image::format.  Each #define identifies a
+ * particular layout of sample data and, if present, alpha values.  There are
+ * separate defines for each of the two component encodings.
+ *
+ * A format is built up using single bit flag values.  All combinations are
+ * valid.  Formats can be built up from the flag values or you can use one of
+ * the predefined values below.  When testing formats always use the FORMAT_FLAG
+ * macros to test for individual features - future versions of the library may
+ * add new flags.
+ *
+ * When reading or writing color-mapped images the format should be set to the
+ * format of the entries in the color-map then png_image_{read,write}_colormap
+ * called to read or write the color-map and set the format correctly for the
+ * image data.  Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
+ *
+ * NOTE: libpng can be built with particular features disabled. If you see
+ * compiler errors because the definition of one of the following flags has been
+ * compiled out it is because libpng does not have the required support.  It is
+ * possible, however, for the libpng configuration to enable the format on just
+ * read or just write; in that case you may see an error at run time.  You can
+ * guard against this by checking for the definition of the appropriate
+ * "_SUPPORTED" macro, one of:
+ *
+ *    PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
+ */
+#define PNG_FORMAT_FLAG_ALPHA    0x01U /* format with an alpha channel */
+#define PNG_FORMAT_FLAG_COLOR    0x02U /* color format: otherwise grayscale */
+#define PNG_FORMAT_FLAG_LINEAR   0x04U /* 2-byte channels else 1-byte */
+#define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+#  define PNG_FORMAT_FLAG_BGR    0x10U /* BGR colors, else order is RGB */
+#endif
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+#  define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
+#endif
+
+#define PNG_FORMAT_FLAG_ASSOCIATED_ALPHA 0x40U /* alpha channel is associated */
+
+/* Commonly used formats have predefined macros.
+ *
+ * First the single byte (sRGB) formats:
+ */
+#define PNG_FORMAT_GRAY 0
+#define PNG_FORMAT_GA   PNG_FORMAT_FLAG_ALPHA
+#define PNG_FORMAT_AG   (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
+#define PNG_FORMAT_RGB  PNG_FORMAT_FLAG_COLOR
+#define PNG_FORMAT_BGR  (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
+#define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
+#define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
+#define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
+#define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
+
+/* Then the linear 2-byte formats.  When naming these "Y" is used to
+ * indicate a luminance (gray) channel.
+ */
+#define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
+#define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
+#define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
+#define PNG_FORMAT_LINEAR_RGB_ALPHA \
+   (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
+
+/* With color-mapped formats the image data is one byte for each pixel, the byte
+ * is an index into the color-map which is formatted as above.  To obtain a
+ * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
+ * to one of the above definitions, or you can use one of the definitions below.
+ */
+#define PNG_FORMAT_RGB_COLORMAP  (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_BGR_COLORMAP  (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
+
+/* PNG_IMAGE macros
+ *
+ * These are convenience macros to derive information from a png_image
+ * structure.  The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
+ * actual image sample values - either the entries in the color-map or the
+ * pixels in the image.  The PNG_IMAGE_PIXEL_ macros return corresponding values
+ * for the pixels and will always return 1 for color-mapped formats.  The
+ * remaining macros return information about the rows in the image and the
+ * complete image.
+ *
+ * NOTE: All the macros that take a png_image::format parameter are compile time
+ * constants if the format parameter is, itself, a constant.  Therefore these
+ * macros can be used in array declarations and case labels where required.
+ * Similarly the macros are also pre-processor constants (sizeof is not used) so
+ * they can be used in #if tests.
+ *
+ * First the information about the samples.
+ */
+#define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
+   (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
+   /* Return the total number of channels in a given format: 1..4 */
+
+#define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
+   ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
+   /* Return the size in bytes of a single component of a pixel or color-map
+    * entry (as appropriate) in the image: 1 or 2.
+    */
+
+#define PNG_IMAGE_SAMPLE_SIZE(fmt)\
+   (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
+   /* This is the size of the sample data for one sample.  If the image is
+    * color-mapped it is the size of one color-map entry (and image pixels are
+    * one byte in size), otherwise it is the size of one image pixel.
+    */
+
+#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
+   (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
+   /* The maximum size of the color-map required by the format expressed in a
+    * count of components.  This can be used to compile-time allocate a
+    * color-map:
+    *
+    * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
+    *
+    * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
+    *
+    * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+    * information from one of the png_image_begin_read_ APIs and dynamically
+    * allocate the required memory.
+    */
+
+/* Corresponding information about the pixels */
+#define PNG_IMAGE_PIXEL_(test,fmt)\
+   (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
+
+#define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
+   PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
+   /* The number of separate channels (components) in a pixel; 1 for a
+    * color-mapped image.
+    */
+
+#define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
+   PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
+   /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
+    * image.
+    */
+
+#define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
+   /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
+
+/* Information about the whole row, or whole image */
+#define PNG_IMAGE_ROW_STRIDE(image)\
+   (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
+   /* Return the total number of components in a single row of the image; this
+    * is the minimum 'row stride', the minimum count of components between each
+    * row.  For a color-mapped image this is the minimum number of bytes in a
+    * row.
+    *
+    * WARNING: this macro overflows for some images with more than one component
+    * and very large image widths.  libpng will refuse to process an image where
+    * this macro would overflow.
+    */
+
+#define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
+   (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
+   /* Return the size, in bytes, of an image buffer given a png_image and a row
+    * stride - the number of components to leave space for in each row.
+    *
+    * WARNING: this macro overflows a 32-bit integer for some large PNG images,
+    * libpng will refuse to process an image where such an overflow would occur.
+    */
+
+#define PNG_IMAGE_SIZE(image)\
+   PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
+   /* Return the size, in bytes, of the image in memory given just a png_image;
+    * the row stride is the minimum stride required for the image.
+    */
+
+#define PNG_IMAGE_COLORMAP_SIZE(image)\
+   (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
+   /* Return the size, in bytes, of the color-map of this image.  If the image
+    * format is not a color-map format this will return a size sufficient for
+    * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
+    * you don't want to allocate a color-map in this case.
+    */
+
+/* PNG_IMAGE_FLAG_*
+ *
+ * Flags containing additional information about the image are held in the
+ * 'flags' field of png_image.
+ */
+#define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
+   /* This indicates that the RGB values of the in-memory bitmap do not
+    * correspond to the red, green and blue end-points defined by sRGB.
+    */
+
+#define PNG_IMAGE_FLAG_FAST 0x02
+   /* On write emphasise speed over compression; the resultant PNG file will be
+    * larger but will be produced significantly faster, particular for large
+    * images.  Do not use this option for images which will be distributed, only
+    * used it when producing intermediate files that will be read back in
+    * repeatedly.  For a typical 24-bit image the option will double the read
+    * speed at the cost of increasing the image size by 25%, however for many
+    * more compressible images the PNG file can be 10 times larger with only a
+    * slight speed gain.
+    */
+
+#define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
+   /* On read if the image is a 16-bit per component image and there is no gAMA
+    * or sRGB chunk assume that the components are sRGB encoded.  Notice that
+    * images output by the simplified API always have gamma information; setting
+    * this flag only affects the interpretation of 16-bit images from an
+    * external source.  It is recommended that the application expose this flag
+    * to the user; the user can normally easily recognize the difference between
+    * linear and sRGB encoding.  This flag has no effect on write - the data
+    * passed to the write APIs must have the correct encoding (as defined
+    * above.)
+    *
+    * If the flag is not set (the default) input 16-bit per component data is
+    * assumed to be linear.
+    *
+    * NOTE: the flag can only be set after the png_image_begin_read_ call,
+    * because that call initializes the 'flags' field.
+    */
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+/* READ APIs
+ * ---------
+ *
+ * The png_image passed to the read APIs must have been initialized by setting
+ * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
+ */
+#ifdef PNG_STDIO_SUPPORTED
+PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
+   const char *file_name));
+   /* The named file is opened for read and the image header is filled in
+    * from the PNG header in the file.
+    */
+
+PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
+   FILE* file));
+   /* The PNG header is read from the stdio FILE object. */
+#endif /* STDIO */
+
+PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
+   png_const_voidp memory, size_t size));
+   /* The PNG header is read from the given memory buffer. */
+
+PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
+   png_const_colorp background, void *buffer, png_int_32 row_stride,
+   void *colormap));
+   /* Finish reading the image into the supplied buffer and clean up the
+    * png_image structure.
+    *
+    * row_stride is the step, in byte or 2-byte units as appropriate,
+    * between adjacent rows.  A positive stride indicates that the top-most row
+    * is first in the buffer - the normal top-down arrangement.  A negative
+    * stride indicates that the bottom-most row is first in the buffer.
+    *
+    * background need only be supplied if an alpha channel must be removed from
+    * a png_byte format and the removal is to be done by compositing on a solid
+    * color; otherwise it may be NULL and any composition will be done directly
+    * onto the buffer.  The value is an sRGB color to use for the background,
+    * for grayscale output the green channel is used.
+    *
+    * background must be supplied when an alpha channel must be removed from a
+    * single byte color-mapped output format, in other words if:
+    *
+    * 1) The original format from png_image_begin_read_from_* had
+    *    PNG_FORMAT_FLAG_ALPHA set.
+    * 2) The format set by the application does not.
+    * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
+    *    PNG_FORMAT_FLAG_LINEAR *not* set.
+    *
+    * For linear output removing the alpha channel is always done by compositing
+    * on black and background is ignored.
+    *
+    * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set.  It must
+    * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
+    * image->colormap_entries will be updated to the actual number of entries
+    * written to the colormap; this may be less than the original value.
+    */
+
+PNG_EXPORT(238, void, png_image_free, (png_imagep image));
+   /* Free any data allocated by libpng in image->opaque, setting the pointer to
+    * NULL.  May be called at any time after the structure is initialized.
+    */
+#endif /* SIMPLIFIED_READ */
+
+#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+/* WRITE APIS
+ * ----------
+ * For write you must initialize a png_image structure to describe the image to
+ * be written.  To do this use memset to set the whole structure to 0 then
+ * initialize fields describing your image.
+ *
+ * version: must be set to PNG_IMAGE_VERSION
+ * opaque: must be initialized to NULL
+ * width: image width in pixels
+ * height: image height in rows
+ * format: the format of the data (image and color-map) you wish to write
+ * flags: set to 0 unless one of the defined flags applies; set
+ *    PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
+ *    values do not correspond to the colors in sRGB.
+ * colormap_entries: set to the number of entries in the color-map (0 to 256)
+ */
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
+   const char *file, int convert_to_8bit, const void *buffer,
+   png_int_32 row_stride, const void *colormap));
+   /* Write the image to the named file. */
+
+PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
+   int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
+   const void *colormap));
+   /* Write the image to the given (FILE*). */
+#endif /* SIMPLIFIED_WRITE_STDIO */
+
+/* With all write APIs if image is in one of the linear formats with 16-bit
+ * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
+ * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
+ * encoded PNG file is written.
+ *
+ * With color-mapped data formats the colormap parameter point to a color-map
+ * with at least image->colormap_entries encoded in the specified format.  If
+ * the format is linear the written PNG color-map will be converted to sRGB
+ * regardless of the convert_to_8_bit flag.
+ *
+ * With all APIs row_stride is handled as in the read APIs - it is the spacing
+ * from one row to the next in component sized units (1 or 2 bytes) and if
+ * negative indicates a bottom-up row layout in the buffer.  If row_stride is
+ * zero, libpng will calculate it for you from the image width and number of
+ * channels.
+ *
+ * Note that the write API does not support interlacing, sub-8-bit pixels or
+ * most ancillary chunks.  If you need to write text chunks (e.g. for copyright
+ * notices) you need to use one of the other APIs.
+ */
+
+PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
+   png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit,
+   const void *buffer, png_int_32 row_stride, const void *colormap));
+   /* Write the image to the given memory buffer.  The function both writes the
+    * whole PNG data stream to *memory and updates *memory_bytes with the count
+    * of bytes written.
+    *
+    * 'memory' may be NULL.  In this case *memory_bytes is not read however on
+    * success the number of bytes which would have been written will still be
+    * stored in *memory_bytes.  On failure *memory_bytes will contain 0.
+    *
+    * If 'memory' is not NULL it must point to memory[*memory_bytes] of
+    * writeable memory.
+    *
+    * If the function returns success memory[*memory_bytes] (if 'memory' is not
+    * NULL) contains the written PNG data.  *memory_bytes will always be less
+    * than or equal to the original value.
+    *
+    * If the function returns false and *memory_bytes was not changed an error
+    * occurred during write.  If *memory_bytes was changed, or is not 0 if
+    * 'memory' was NULL, the write would have succeeded but for the memory
+    * buffer being too small.  *memory_bytes contains the required number of
+    * bytes and will be bigger that the original value.
+    */
+
+#define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\
+   row_stride, colormap)\
+   png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\
+         row_stride, colormap)
+   /* Return the amount of memory in 'size' required to compress this image.
+    * The png_image structure 'image' must be filled in as in the above
+    * function and must not be changed before the actual write call, the buffer
+    * and all other parameters must also be identical to that in the final
+    * write call.  The 'size' variable need not be initialized.
+    *
+    * NOTE: the macro returns true/false, if false is returned 'size' will be
+    * set to zero and the write failed and probably will fail if tried again.
+    */
+
+/* You can pre-allocate the buffer by making sure it is of sufficient size
+ * regardless of the amount of compression achieved.  The buffer size will
+ * always be bigger than the original image and it will never be filled.  The
+ * following macros are provided to assist in allocating the buffer.
+ */
+#define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height)
+   /* The number of uncompressed bytes in the PNG byte encoding of the image;
+    * uncompressing the PNG IDAT data will give this number of bytes.
+    *
+    * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this
+    * macro can because of the extra bytes used in the PNG byte encoding.  You
+    * need to avoid this macro if your image size approaches 2^30 in width or
+    * height.  The same goes for the remainder of these macros; they all produce
+    * bigger numbers than the actual in-memory image size.
+    */
+#ifndef PNG_ZLIB_MAX_SIZE
+#  define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U)
+   /* An upper bound on the number of compressed bytes given 'b' uncompressed
+    * bytes.  This is based on deflateBounds() in zlib; different
+    * implementations of zlib compression may conceivably produce more data so
+    * if your zlib implementation is not zlib itself redefine this macro
+    * appropriately.
+    */
+#endif
+
+#define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\
+   PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image))
+   /* An upper bound on the size of the data in the PNG IDAT chunks. */
+
+#define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\
+   ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\
+    (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\
+    12U+3U*(image).colormap_entries/*PLTE data*/+\
+    (((image).format&PNG_FORMAT_FLAG_ALPHA)?\
+    12U/*tRNS*/+(image).colormap_entries:0U):0U)+\
+    12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size))
+   /* A helper for the following macro; if your compiler cannot handle the
+    * following macro use this one with the result of
+    * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most
+    * compilers should handle this just fine.)
+    */
+
+#define PNG_IMAGE_PNG_SIZE_MAX(image)\
+   PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image))
+   /* An upper bound on the total length of the PNG data stream for 'image'.
+    * The result is of type png_alloc_size_t, on 32-bit systems this may
+    * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will
+    * run out of buffer space but return a corrected size which should work.
+    */
+#endif /* SIMPLIFIED_WRITE */
+/*******************************************************************************
+ *  END OF SIMPLIFIED API
+ ******************************************************************************/
+#endif /* SIMPLIFIED_{READ|WRITE} */
+
+/*******************************************************************************
+ * Section 6: IMPLEMENTATION OPTIONS
+ *******************************************************************************
+ *
+ * Support for arbitrary implementation-specific optimizations.  The API allows
+ * particular options to be turned on or off.  'Option' is the number of the
+ * option and 'onoff' is 0 (off) or non-0 (on).  The value returned is given
+ * by the PNG_OPTION_ defines below.
+ *
+ * HARDWARE: normally hardware capabilities, such as the Intel SSE instructions,
+ *           are detected at run time, however sometimes it may be impossible
+ *           to do this in user mode, in which case it is necessary to discover
+ *           the capabilities in an OS specific way.  Such capabilities are
+ *           listed here when libpng has support for them and must be turned
+ *           ON by the application if present.
+ *
+ * SOFTWARE: sometimes software optimizations actually result in performance
+ *           decrease on some architectures or systems, or with some sets of
+ *           PNG images.  'Software' options allow such optimizations to be
+ *           selected at run time.
+ */
+#ifdef PNG_SET_OPTION_SUPPORTED
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+#  define PNG_ARM_NEON   0 /* HARDWARE: ARM Neon SIMD instructions supported */
+#endif
+#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
+#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
+#ifdef PNG_MIPS_MSA_API_SUPPORTED
+#  define PNG_MIPS_MSA   6 /* HARDWARE: MIPS Msa SIMD instructions supported */
+#endif
+#define PNG_IGNORE_ADLER32 8
+#ifdef PNG_POWERPC_VSX_API_SUPPORTED
+#  define PNG_POWERPC_VSX   10 /* HARDWARE: PowerPC VSX SIMD instructions supported */
+#endif
+#define PNG_OPTION_NEXT  12 /* Next option - numbers must be even */
+
+/* Return values: NOTE: there are four values and 'off' is *not* zero */
+#define PNG_OPTION_UNSET   0 /* Unset - defaults to off */
+#define PNG_OPTION_INVALID 1 /* Option number out of range */
+#define PNG_OPTION_OFF     2
+#define PNG_OPTION_ON      3
+
+PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
+   int onoff));
+#endif /* SET_OPTION */
+
+/*******************************************************************************
+ *  END OF HARDWARE AND SOFTWARE OPTIONS
+ ******************************************************************************/
+
+/* Maintainer: Put new public prototypes here ^, in libpng.3, in project
+ * defs, and in scripts/symbols.def.
+ */
+
+/* The last ordinal number (this is the *last* one already used; the next
+ * one to use is one more than this.)
+ */
+#ifdef PNG_EXPORT_LAST_ORDINAL
+  PNG_EXPORT_LAST_ORDINAL(249);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PNG_VERSION_INFO_ONLY */
+/* Do not put anything past this line */
+#endif /* PNG_H */
diff --git a/extern/libpng/pngbar.jpg b/extern/libpng/pngbar.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..70ba8d817ce433788c7933dbe3c29c3e384b2b0a
GIT binary patch
literal 2498
zcmb79cR1UN8ve<!Vud7}HYCK}tM;Y{Z5^vrsFE6uJ&GDt6fJ6Y=`oAe-h^XIQ7v*#
zZO1A~(WaF)HOtle+~>LX-}`>=f8Y0x?_}m=8Q`%n#hU_5OiaM90Zxtq1>=CgTfsNH
zyhE`{nwsjeShHXcFRV>~hi`yq2v*YHBRtd~Fu*+^LY^4lCw1}<U<`mkpkF)%<djfW
zC=>#Lva_%-vvRO=aKPAMFitLB9!@Se7YxRO;(_xakVqs4H@^T1A;613B7T`LfloCM
zC>s>YhTw#8BK~ij^a5~J00TIJnM42(oCyqPI(Y@00RRyA^t=CpnFWBbLcymyB_03-
z0x_M|W@3T<`-BN}TAvxt!Yd50@*zZ&*pN77LnCW9lz^y8aNMcnEYqn3{J(Y(W-t^0
zvHZ$XfCC^V5CqH&h5jdw2?Phg5ME(JD6^7?wOdfuSH8H0zP}N;;+36~Ie_ET2?Phj
z0ewJu_XPOzrM!FkVBFSWa?9PHSVQF9@l6YED#^WWRML1J9VDQieoKN{=G;@B(Vmqw
zMZd`y)ni0|7a{dGH#QBu4Xb>^8Ml-38dtbR*{4J6CiE}A`n<^Swi_b~53dp@Oz5&x
zqIb>@R2bY|^Eg5Q^oZrcolUy~e~ev4`E;SpK(~nwOpGHYx7IEN6TgtCZ%ql2@{}O=
zB=jD|t!NkbZ`gujXu2t1GZEV?OI;QB^sVbc{HllYU92vX0u%;zs?5Dy7i5b^Vr}Pn
zO2G4GXu7^$QmgA^)I4+H4Ve#&F8{pR>+ENwX4HwzetiUp&~J{h-wxp)&2&qMG9ULl
z$1sGXW1&H@50#Izy=lZUfjypz`|x(CS!BmIDmt4<-iM+7vJJYh6Ok&Y`9uL<Z7G&l
z=3{Ft5*;tKL?$<)?4vlk;&S(F^p?OABxel=x4PsX`WCZ|W62+S?$a?rPIXSZEfap*
zCA#P4K5cAmskO?sY&lfF8?d~sK}__NwBcG0#y>Dz-dii|{T@&nMOnhYGW-(Yq<%v=
zZ{=JMeWTwA?P4UG8a$$%3#A_D7*<`B{srsRec$8y$6ez;HO0+<=@)~a+C#KD$fFie
zOF5lh(}n6`?kJ=#rB8?(qO_~`d`n%$zP0)o`DHOCeo?6M-Pn1fN6p1D_{#*0&JIPU
zL@9JFTVPL!MG(xN{Pyi$)cs@-UVOt7&mCx*p!Qt+LYRr<MCQctCLjHK$pfn;z1hy?
zhFmm?j52ZVvPpd!#yTf?y@~zp8GfD<V5X=(OGEIkLe9d<@#vRl>oDYFGACZJ{8Pxa
zhc4YRL#jc2?yi*%aQ(San~2E>x<f&P-V^$lGs#wBuczC`M-$FkId!>W1QR0J9uq>9
zE|N+~DEC)g{=F~&W?nheQJ?`Q<2i%Wz?M||p-DL5&AOs`qIe3z=N#%2ExTl7#Mi~t
zZT<r>vmnY2L6R<L?}=!a^}0y&tDneUO^{=jlDX0*0(q0An3ZpRXs~aFWj?wc!@|JS
zoJ}8?kQEZIJ!~X}(Vq=O=WA*G<etkK*1WN3e@z>G=bnbgRr9M+u}{jp7ydMJN^<vU
z8*REm8S<<yCi!ysyt-_fBK15S#&Iq4Oq_vqqaqf#rB}lM37i1)g%&n6z5cj6HKXWp
zr;h82KDrgS%U_=1+gE9qzAg3XQVK|IImkvV0~c{%yDN6Z@(53<9w56F`59!DfVj&f
zA{jKZDuFHuxr|G-E@O6G7LMzx1?E@JDXU&Y$E}*0N^361T4w0bA&iZK_zlU8unP|#
z$;UYVwd$Vq*B^YkFeM97(bDysc!@yvV@4JpY6i}*op6?HwY<|z2_K`pntZ8OR(!AD
zrNx^-_2va7POIEZbah179#k-76p9WDU!vrtxfFcr2UMI&bDD%3^reQ;KMK)x%U^XO
zscl{Psv|9LCyKoutCNAc%qc&Ma^a$s5gU9ie{#6Iz9gH(=i5t{dScHG8Eb9QSa2b@
zo{jo&2E!NKU^_h*F=y_X*}?2({66=|&QF~TYAO0@cj|?)>)W@t){SwRelgUb%&^y1
zM;W@kz|uUoUabJ?0dbrrlPe>APntXLz&pJ5ZWI7}GEh1`;2^(^ytgu48%@k}`m_4R
zx8US1L-x+#p75_R@wMZVM}ykuYvioTTGW)v@utp6&FdCbVm5jv1($E4n`7P(vX8P^
zVZA#7-KlKgbTX}&!a_R%ta^0&^b~I$WKg~SIROeW8CO-de{#3jS6!TXFi85;P@Hrz
zD3>)2F0f1;VrK&%21hW;jd0Cjw4<mw8CV7UVXS`sw)0`|tmkMbu5>?npnIr&aVCT_
zW9a^Bg^fd&pImbNpxTP+{rooTc`NU48`F^mV8?f=97sYHnM7{LO)G6#omwpLj@zjk
z*`m5o3~<=GP<O*VmcrpnAG_a2N{tsh-f|k`i<yyGXGABaCFyG%>;|qAvDunf<-pg&
zIH~t>Us-XJV%rkrKOD99=3flubRj$V{UNE2PCJI@Qi7&wDXM|x@Dll=Tj)D@Y(u1P
z7_yCfQ%}|zKKprCcz*XtvG}TKViW44NE~ZF&3pW4f2!sm`cI`U`Bl!2_PqS3Dvok5
z=2eTiaWh#`Q&nhOeYk8Y2gu}DUKS%W-&K5bD>U`DQo92*Z9Jvl-A7zo%D^O5+z3<A
zbZxr1jz3UJH7r5k@GR}7Xwvu0Va8I?Z1teASZu_c|HVgndKPR!oZo+l5bV~?C&3wM
zcS{g1%h_fUL#vYy-qs4us(E#Y$?z+_>*TS2sjBs^v)SGJg_-$$y+3;FN@u#o{#rqd
z=-;Zemc);1)~-n;ZNYgD*QCx)qTS?(6>`Yxu0|T02j9{jA-iY!XBs6VtKgN(?M>3M
zXitp$#9|Y^aqefnpO5s_bc&VI`Mol8lb36szrH?8J9^Y{Sh=Zut;vy9EAFY*!eBw<
zUh1>Fup<1+##XO=O2huD7w?@yH~akK6(i-EANrw@1tl$;?SdE;AJIJyTU&yrti_SX
zqL2K}JyH4R*vHyPyly4H@@Qky6>b`Z!-~dp<=^<0ql8jCIzJ{n2`02PuA?k^A&hB?
zljJT{WGG{Bb%mft`m0YCNhgQcH?}Ga`o4KT7r9mpTO|G-ajjf)r<b9NJD^U_OV|bd
zIMdC?AJ;m0ml-XtGZF8}Md-?DEBEKdcw6^ppy?MF7!EU&=q;1{qeKi<pjux17~xi1
V^??kj$kLq2r$#fD{2!gn{tGu6WuyQA

literal 0
HcmV?d00001

diff --git a/extern/libpng/pngbar.png b/extern/libpng/pngbar.png
new file mode 100644
index 0000000000000000000000000000000000000000..49798c8ed957b407692306792a73df4312f80cbb
GIT binary patch
literal 2399
zcmV-l3840gP)<h;3K|Lk000e1NJLTq003A30018d0{{R3R2KTu00004XF*Lt006O%
z3;baP00001b5ch_0olnce*gdiyHHG2MF0Q*ud%PGtErit!ESMRrKhFdNl9>Uae~l{
z0Rja6`T3xspr4_iba{e!dVHCinSz3e@1>=%j($2G9;~mjBv2nTG{hSR28W4<;$UEa
zfq+#nVBJJS0RaHmC@AQFfQX5U(+mu00070t%A%vz78nt@y3y1S5N2m)Kc7E!n|s1o
zS3*LZ`|ImCIy_xnT}Vn#B_<}-6cj!`B>eC1D=aTfO-&XS7mt#WfPvpvG$H~507gef
za(0FG_V)er^K^NAv$WC-3=ME`<MOzf3JMF!%gqM}2pkm_0s;d800IC20TmAqQ&m}$
zl-e*cFfT7J>ynZ!EiHe1F4i6%tFFzXq(o3jLNqluBO@b<ijo~29n8+mJUv1g9T{I>
zVbTT$78e$QPf^Cm#xylL6B84MYEWEsVPscG4Gj%}gp7rShJJ*J1_uTQ1qZgcwgm+R
zTU=lS0|Z`PB(t=$0s#U60RaF30IsgC78d%fuB?oX+;MYqIXXKmD<L8^7p1I`Gcq+L
z9~!KzMU#}1>vVH6GZr>DJ8*F|pP|?3h={zu&lnR8iH(zuj*X0tj8%hK4-gJ}V^=2}
z6>oEP2?_mre}vT-7)}5HC?_Km6cv1ad;tIecYA?^h0qZY6Aum%b9;T@R8)kCkwQa5
zadmqS2M0SlJZ)}m(EtEcS6dMa3_n3bUt?)wWMf%cS%!(3`QP6|MM@eP`5+-7d3AOF
z|Nm+%D{E|VNkkrIXlz47LkkNGKtMq3?d<#K=S5UV_RGudo}K{#0%vG&=I7>ARK#Xx
zZ!<JA@vpCkjf^!&IBjluDk>^wXXe#HK_DO?>Sbn6Qdo$IQAs2u8X6iK7#qpU$!=|P
zH#j{eCMlYoeM(75KtVqc5c_+8WeN%km6n;gySbjFueP_g0|EoHwX*;K|7dG)!Bu-G
z000IGNkl<ZNXNC-{a4dg7zgm%Ds#$9aO%_!5vM|gK|v(Ehyz7o$gsR91A7@%tg}GH
zwKWa|Q79-#2MmNMGLQ`^NO|i30hx+!1_g#nR$;(u883gvZUS1+9rXu&&Pkh-_I%FG
zH}|<WpzZxsDro!s_jgt6jnxW3+i&oVwP|2r!0*Bv|5j_PA6ZyHzqU-E=XA1mTI>Ht
z*vcw)0ZfC}7KY%R=*angFf7GDQDX{kit>gDqYzS58b_&yP)Sh~f_vJw^;p^2y#yCM
zISs%G832=BMOOfjy#g<itZ8sjh%qAAW^Bv`*60mTj5P%F2ncxs9uL7=tJa71X0`2K
z0Fy^{M|5Pb+EOU@+MSv0n!aVTywC_UQP^}tC@~Q!V)zipp-xQjU?GoCv#<-!V>7m@
zt+jh(w*X#u^vDspeASlpa4&Rno;k@j!sy{`WCR+Uq@`vIjHM+IP*3zXu&|I&vvBhr
zt5-6<$<K?VzkYb!TlQ6k@NB?sS(^L&C?LcJbxBeV4P!bPxB&n$q*1yoOw7%S($HnS
z*7M-)+qaW{S-Kae)!%Tptav&c{nXvky?Qv11bdAzqy|N}f`*+93>;<(2f0#8w1lUp
z1?ZrY7`SR}R`W7r#`?tgl6cdPoX?M$DvQtWI;4E?_jQN%)H5pc$G$QI+vc!SEpCkx
z#+g9_7fww<Ob59J3^Re~!wel*92>>9<vl%HjU$dOFRnk@>KozuLwWI;j6+9TpA<P9
z^!O+Gv8tR#@ILK62><YWiw3doY0iqB7loixbLERs)q}vZn(CFBj4y*vlf@G*mx4&A
z#KUY9s5`U+a0(5K8Jrmxni<f*xjYVYjl<l5$<$mFw;W52u(PJ~Y?ErS>hcZ3t)y?l
zdFG(xs{LWrE<if(Vc~I42F4{cZ9@aP%LPv6r}8nqK*B}Wq^3BIi41HMZ9dI+=E0g7
z^F_8z^&!U!ZcA%+<m}Ld1loT%61KFZuCA_yf&H}p42&~(3}Bo-MYM#lsVRdE!RT5e
zjyKZJ*eLcdY-zH1X85z8H1de_f&$lwUz(Z{Gt=$uzsZzqW}e2MV_<)+-|UD53=I3#
z1ks;FbKo-yr|>9KT-raI@mim4p&N{FMfnYvkx$&R<(ms07RfJb`ikXw53l+@$=(}P
z?MpK-^c){YFoBt|a4?lG5TfY@J<<>?PQod%2Mgco&28>|0SA}+mYBOllOs`!S5By%
zPP)yMN8hY0FHucYC;n_6!ovRAX#_Va6gmb@(5FOo!%@D@y8%T(VK`nksAFI>hf954
z%;R4p&z*B}R#o1+ANee}?qI;Zm|;~&O?-uKytC6Dx4SG1Pcbm+Lj?nKq_BGl<cL6&
z0l_s1IIa`6GVq<;+E_=c`7M1i?-E&AIXQIfxDaGy0HG{kNLEo9G~3b;`fob$KNDAn
z#=meL|LNn{ylm@ycy*OSUS@~aqoIz7JO_uo2>H;X_Kt|nbMUG0>1pkOx7k6gb9<~7
zEJCZ>+w;OZR<y6^2+x~49dZqygKaNrbM_@`A<7c1j$E{mrQ&LXNj}6do<i42m_idG
zhHdGp(6!btt!~$jfdKNv^%F~Pf@{}6Kp=U2GALj!3cqPvwDEaD+=UP)KtA9=x+|;(
zEonGTVf=o+#6ZV{H8QY|V_Vy;()sXZo3KF}_YliH(H4`BJIT&qnMJ)MUN8#}B%?Gu
zJvX8U6{ChxV-}EBaA;naq7lI&E-X_NrX(pD*wNbVgWLrfSN4qv`{<FrU6J=?Ep_1A
z7U{j=!ag@6tWBQYiPMx=VW9K7(TD}3JoFoa0TVAD46^X@tXDVFAV7k3Bmj58T@o<g
z>w?IW&lmbl5aqEGH3-e+iMsSUx=|fB7lp(Cl}Z05;e)elg=25lhPU3OFC-`X4O~Pp
z(+u8SxX6@Nu-gU$cM%?iDf;}>eg@uPwZ7NbAfwc4%LKv$AESApwMAQTgR)Bj)d}7P
zwCAfKkJo5opoC@6Lg<3Mcwvcs4!^5<=}qW6{9V<j###+PoD95|`VaK6Ze=au@=X8$
z04#JxSad^gaCvfRXJ~W)F*!LmAV+d#XCP8<Wo&O|b08>gWp{KyaBpI7crIgaZ7IUp
RQSJZ$002ovPDHLkV1iCKFfIT9

literal 0
HcmV?d00001

diff --git a/extern/libpng/pngconf.h b/extern/libpng/pngconf.h
new file mode 100644
index 0000000000..927a769dbe
--- /dev/null
+++ b/extern/libpng/pngconf.h
@@ -0,0 +1,623 @@
+
+/* pngconf.h - machine-configurable file for libpng
+ *
+ * libpng version 1.6.37
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Any machine specific code is near the front of this file, so if you
+ * are configuring libpng for a machine, you may want to read the section
+ * starting here down to where it starts to typedef png_color, png_text,
+ * and png_info.
+ */
+
+#ifndef PNGCONF_H
+#define PNGCONF_H
+
+#ifndef PNG_BUILDING_SYMBOL_TABLE /* else includes may cause problems */
+
+/* From libpng 1.6.0 libpng requires an ANSI X3.159-1989 ("ISOC90") compliant C
+ * compiler for correct compilation.  The following header files are required by
+ * the standard.  If your compiler doesn't provide these header files, or they
+ * do not match the standard, you will need to provide/improve them.
+ */
+#include <limits.h>
+#include <stddef.h>
+
+/* Library header files.  These header files are all defined by ISOC90; libpng
+ * expects conformant implementations, however, an ISOC90 conformant system need
+ * not provide these header files if the functionality cannot be implemented.
+ * In this case it will be necessary to disable the relevant parts of libpng in
+ * the build of pnglibconf.h.
+ *
+ * Prior to 1.6.0 string.h was included here; the API changes in 1.6.0 to not
+ * include this unnecessary header file.
+ */
+
+#ifdef PNG_STDIO_SUPPORTED
+   /* Required for the definition of FILE: */
+#  include <stdio.h>
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+   /* Required for the definition of jmp_buf and the declaration of longjmp: */
+#  include <setjmp.h>
+#endif
+
+#ifdef PNG_CONVERT_tIME_SUPPORTED
+   /* Required for struct tm: */
+#  include <time.h>
+#endif
+
+#endif /* PNG_BUILDING_SYMBOL_TABLE */
+
+/* Prior to 1.6.0, it was possible to turn off 'const' in declarations,
+ * using PNG_NO_CONST.  This is no longer supported.
+ */
+#define PNG_CONST const /* backward compatibility only */
+
+/* This controls optimization of the reading of 16-bit and 32-bit
+ * values from PNG files.  It can be set on a per-app-file basis: it
+ * just changes whether a macro is used when the function is called.
+ * The library builder sets the default; if read functions are not
+ * built into the library the macro implementation is forced on.
+ */
+#ifndef PNG_READ_INT_FUNCTIONS_SUPPORTED
+#  define PNG_USE_READ_MACROS
+#endif
+#if !defined(PNG_NO_USE_READ_MACROS) && !defined(PNG_USE_READ_MACROS)
+#  if PNG_DEFAULT_READ_MACROS
+#    define PNG_USE_READ_MACROS
+#  endif
+#endif
+
+/* COMPILER SPECIFIC OPTIONS.
+ *
+ * These options are provided so that a variety of difficult compilers
+ * can be used.  Some are fixed at build time (e.g. PNG_API_RULE
+ * below) but still have compiler specific implementations, others
+ * may be changed on a per-file basis when compiling against libpng.
+ */
+
+/* The PNGARG macro was used in versions of libpng prior to 1.6.0 to protect
+ * against legacy (pre ISOC90) compilers that did not understand function
+ * prototypes.  It is not required for modern C compilers.
+ */
+#ifndef PNGARG
+#  define PNGARG(arglist) arglist
+#endif
+
+/* Function calling conventions.
+ * =============================
+ * Normally it is not necessary to specify to the compiler how to call
+ * a function - it just does it - however on x86 systems derived from
+ * Microsoft and Borland C compilers ('IBM PC', 'DOS', 'Windows' systems
+ * and some others) there are multiple ways to call a function and the
+ * default can be changed on the compiler command line.  For this reason
+ * libpng specifies the calling convention of every exported function and
+ * every function called via a user supplied function pointer.  This is
+ * done in this file by defining the following macros:
+ *
+ * PNGAPI    Calling convention for exported functions.
+ * PNGCBAPI  Calling convention for user provided (callback) functions.
+ * PNGCAPI   Calling convention used by the ANSI-C library (required
+ *           for longjmp callbacks and sometimes used internally to
+ *           specify the calling convention for zlib).
+ *
+ * These macros should never be overridden.  If it is necessary to
+ * change calling convention in a private build this can be done
+ * by setting PNG_API_RULE (which defaults to 0) to one of the values
+ * below to select the correct 'API' variants.
+ *
+ * PNG_API_RULE=0 Use PNGCAPI - the 'C' calling convention - throughout.
+ *                This is correct in every known environment.
+ * PNG_API_RULE=1 Use the operating system convention for PNGAPI and
+ *                the 'C' calling convention (from PNGCAPI) for
+ *                callbacks (PNGCBAPI).  This is no longer required
+ *                in any known environment - if it has to be used
+ *                please post an explanation of the problem to the
+ *                libpng mailing list.
+ *
+ * These cases only differ if the operating system does not use the C
+ * calling convention, at present this just means the above cases
+ * (x86 DOS/Windows systems) and, even then, this does not apply to
+ * Cygwin running on those systems.
+ *
+ * Note that the value must be defined in pnglibconf.h so that what
+ * the application uses to call the library matches the conventions
+ * set when building the library.
+ */
+
+/* Symbol export
+ * =============
+ * When building a shared library it is almost always necessary to tell
+ * the compiler which symbols to export.  The png.h macro 'PNG_EXPORT'
+ * is used to mark the symbols.  On some systems these symbols can be
+ * extracted at link time and need no special processing by the compiler,
+ * on other systems the symbols are flagged by the compiler and just
+ * the declaration requires a special tag applied (unfortunately) in a
+ * compiler dependent way.  Some systems can do either.
+ *
+ * A small number of older systems also require a symbol from a DLL to
+ * be flagged to the program that calls it.  This is a problem because
+ * we do not know in the header file included by application code that
+ * the symbol will come from a shared library, as opposed to a statically
+ * linked one.  For this reason the application must tell us by setting
+ * the magic flag PNG_USE_DLL to turn on the special processing before
+ * it includes png.h.
+ *
+ * Four additional macros are used to make this happen:
+ *
+ * PNG_IMPEXP The magic (if any) to cause a symbol to be exported from
+ *            the build or imported if PNG_USE_DLL is set - compiler
+ *            and system specific.
+ *
+ * PNG_EXPORT_TYPE(type) A macro that pre or appends PNG_IMPEXP to
+ *                       'type', compiler specific.
+ *
+ * PNG_DLL_EXPORT Set to the magic to use during a libpng build to
+ *                make a symbol exported from the DLL.  Not used in the
+ *                public header files; see pngpriv.h for how it is used
+ *                in the libpng build.
+ *
+ * PNG_DLL_IMPORT Set to the magic to force the libpng symbols to come
+ *                from a DLL - used to define PNG_IMPEXP when
+ *                PNG_USE_DLL is set.
+ */
+
+/* System specific discovery.
+ * ==========================
+ * This code is used at build time to find PNG_IMPEXP, the API settings
+ * and PNG_EXPORT_TYPE(), it may also set a macro to indicate the DLL
+ * import processing is possible.  On Windows systems it also sets
+ * compiler-specific macros to the values required to change the calling
+ * conventions of the various functions.
+ */
+#if defined(_Windows) || defined(_WINDOWS) || defined(WIN32) ||\
+    defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__)
+  /* Windows system (DOS doesn't support DLLs).  Includes builds under Cygwin or
+   * MinGW on any architecture currently supported by Windows.  Also includes
+   * Watcom builds but these need special treatment because they are not
+   * compatible with GCC or Visual C because of different calling conventions.
+   */
+#  if PNG_API_RULE == 2
+   /* If this line results in an error, either because __watcall is not
+    * understood or because of a redefine just below you cannot use *this*
+    * build of the library with the compiler you are using.  *This* build was
+    * build using Watcom and applications must also be built using Watcom!
+    */
+#    define PNGCAPI __watcall
+#  endif
+
+#  if defined(__GNUC__) || (defined(_MSC_VER) && (_MSC_VER >= 800))
+#    define PNGCAPI __cdecl
+#    if PNG_API_RULE == 1
+   /* If this line results in an error __stdcall is not understood and
+    * PNG_API_RULE should not have been set to '1'.
+    */
+#      define PNGAPI __stdcall
+#    endif
+#  else
+   /* An older compiler, or one not detected (erroneously) above,
+    * if necessary override on the command line to get the correct
+    * variants for the compiler.
+    */
+#    ifndef PNGCAPI
+#      define PNGCAPI _cdecl
+#    endif
+#    if PNG_API_RULE == 1 && !defined(PNGAPI)
+#      define PNGAPI _stdcall
+#    endif
+#  endif /* compiler/api */
+
+  /* NOTE: PNGCBAPI always defaults to PNGCAPI. */
+
+#  if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
+#     error "PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed"
+#  endif
+
+#  if (defined(_MSC_VER) && _MSC_VER < 800) ||\
+      (defined(__BORLANDC__) && __BORLANDC__ < 0x500)
+   /* older Borland and MSC
+    * compilers used '__export' and required this to be after
+    * the type.
+    */
+#    ifndef PNG_EXPORT_TYPE
+#      define PNG_EXPORT_TYPE(type) type PNG_IMPEXP
+#    endif
+#    define PNG_DLL_EXPORT __export
+#  else /* newer compiler */
+#    define PNG_DLL_EXPORT __declspec(dllexport)
+#    ifndef PNG_DLL_IMPORT
+#      define PNG_DLL_IMPORT __declspec(dllimport)
+#    endif
+#  endif /* compiler */
+
+#else /* !Windows */
+#  if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
+#    define PNGAPI _System
+#  else /* !Windows/x86 && !OS/2 */
+   /* Use the defaults, or define PNG*API on the command line (but
+    * this will have to be done for every compile!)
+    */
+#  endif /* other system, !OS/2 */
+#endif /* !Windows/x86 */
+
+/* Now do all the defaulting . */
+#ifndef PNGCAPI
+#  define PNGCAPI
+#endif
+#ifndef PNGCBAPI
+#  define PNGCBAPI PNGCAPI
+#endif
+#ifndef PNGAPI
+#  define PNGAPI PNGCAPI
+#endif
+
+/* PNG_IMPEXP may be set on the compilation system command line or (if not set)
+ * then in an internal header file when building the library, otherwise (when
+ * using the library) it is set here.
+ */
+#ifndef PNG_IMPEXP
+#  if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT)
+   /* This forces use of a DLL, disallowing static linking */
+#    define PNG_IMPEXP PNG_DLL_IMPORT
+#  endif
+
+#  ifndef PNG_IMPEXP
+#    define PNG_IMPEXP
+#  endif
+#endif
+
+/* In 1.5.2 the definition of PNG_FUNCTION has been changed to always treat
+ * 'attributes' as a storage class - the attributes go at the start of the
+ * function definition, and attributes are always appended regardless of the
+ * compiler.  This considerably simplifies these macros but may cause problems
+ * if any compilers both need function attributes and fail to handle them as
+ * a storage class (this is unlikely.)
+ */
+#ifndef PNG_FUNCTION
+#  define PNG_FUNCTION(type, name, args, attributes) attributes type name args
+#endif
+
+#ifndef PNG_EXPORT_TYPE
+#  define PNG_EXPORT_TYPE(type) PNG_IMPEXP type
+#endif
+
+   /* The ordinal value is only relevant when preprocessing png.h for symbol
+    * table entries, so we discard it here.  See the .dfn files in the
+    * scripts directory.
+    */
+
+#ifndef PNG_EXPORTA
+#  define PNG_EXPORTA(ordinal, type, name, args, attributes) \
+      PNG_FUNCTION(PNG_EXPORT_TYPE(type), (PNGAPI name), PNGARG(args), \
+      PNG_LINKAGE_API attributes)
+#endif
+
+/* ANSI-C (C90) does not permit a macro to be invoked with an empty argument,
+ * so make something non-empty to satisfy the requirement:
+ */
+#define PNG_EMPTY /*empty list*/
+
+#define PNG_EXPORT(ordinal, type, name, args) \
+   PNG_EXPORTA(ordinal, type, name, args, PNG_EMPTY)
+
+/* Use PNG_REMOVED to comment out a removed interface. */
+#ifndef PNG_REMOVED
+#  define PNG_REMOVED(ordinal, type, name, args, attributes)
+#endif
+
+#ifndef PNG_CALLBACK
+#  define PNG_CALLBACK(type, name, args) type (PNGCBAPI name) PNGARG(args)
+#endif
+
+/* Support for compiler specific function attributes.  These are used
+ * so that where compiler support is available incorrect use of API
+ * functions in png.h will generate compiler warnings.
+ *
+ * Added at libpng-1.2.41.
+ */
+
+#ifndef PNG_NO_PEDANTIC_WARNINGS
+#  ifndef PNG_PEDANTIC_WARNINGS_SUPPORTED
+#    define PNG_PEDANTIC_WARNINGS_SUPPORTED
+#  endif
+#endif
+
+#ifdef PNG_PEDANTIC_WARNINGS_SUPPORTED
+  /* Support for compiler specific function attributes.  These are used
+   * so that where compiler support is available, incorrect use of API
+   * functions in png.h will generate compiler warnings.  Added at libpng
+   * version 1.2.41.  Disabling these removes the warnings but may also produce
+   * less efficient code.
+   */
+#  if defined(__clang__) && defined(__has_attribute)
+   /* Clang defines both __clang__ and __GNUC__. Check __clang__ first. */
+#    if !defined(PNG_USE_RESULT) && __has_attribute(__warn_unused_result__)
+#      define PNG_USE_RESULT __attribute__((__warn_unused_result__))
+#    endif
+#    if !defined(PNG_NORETURN) && __has_attribute(__noreturn__)
+#      define PNG_NORETURN __attribute__((__noreturn__))
+#    endif
+#    if !defined(PNG_ALLOCATED) && __has_attribute(__malloc__)
+#      define PNG_ALLOCATED __attribute__((__malloc__))
+#    endif
+#    if !defined(PNG_DEPRECATED) && __has_attribute(__deprecated__)
+#      define PNG_DEPRECATED __attribute__((__deprecated__))
+#    endif
+#    if !defined(PNG_PRIVATE)
+#      ifdef __has_extension
+#        if __has_extension(attribute_unavailable_with_message)
+#          define PNG_PRIVATE __attribute__((__unavailable__(\
+             "This function is not exported by libpng.")))
+#        endif
+#      endif
+#    endif
+#    ifndef PNG_RESTRICT
+#      define PNG_RESTRICT __restrict
+#    endif
+
+#  elif defined(__GNUC__)
+#    ifndef PNG_USE_RESULT
+#      define PNG_USE_RESULT __attribute__((__warn_unused_result__))
+#    endif
+#    ifndef PNG_NORETURN
+#      define PNG_NORETURN   __attribute__((__noreturn__))
+#    endif
+#    if __GNUC__ >= 3
+#      ifndef PNG_ALLOCATED
+#        define PNG_ALLOCATED  __attribute__((__malloc__))
+#      endif
+#      ifndef PNG_DEPRECATED
+#        define PNG_DEPRECATED __attribute__((__deprecated__))
+#      endif
+#      ifndef PNG_PRIVATE
+#        if 0 /* Doesn't work so we use deprecated instead*/
+#          define PNG_PRIVATE \
+            __attribute__((warning("This function is not exported by libpng.")))
+#        else
+#          define PNG_PRIVATE \
+            __attribute__((__deprecated__))
+#        endif
+#      endif
+#      if ((__GNUC__ > 3) || !defined(__GNUC_MINOR__) || (__GNUC_MINOR__ >= 1))
+#        ifndef PNG_RESTRICT
+#          define PNG_RESTRICT __restrict
+#        endif
+#      endif /* __GNUC__.__GNUC_MINOR__ > 3.0 */
+#    endif /* __GNUC__ >= 3 */
+
+#  elif defined(_MSC_VER)  && (_MSC_VER >= 1300)
+#    ifndef PNG_USE_RESULT
+#      define PNG_USE_RESULT /* not supported */
+#    endif
+#    ifndef PNG_NORETURN
+#      define PNG_NORETURN   __declspec(noreturn)
+#    endif
+#    ifndef PNG_ALLOCATED
+#      if (_MSC_VER >= 1400)
+#        define PNG_ALLOCATED __declspec(restrict)
+#      endif
+#    endif
+#    ifndef PNG_DEPRECATED
+#      define PNG_DEPRECATED __declspec(deprecated)
+#    endif
+#    ifndef PNG_PRIVATE
+#      define PNG_PRIVATE __declspec(deprecated)
+#    endif
+#    ifndef PNG_RESTRICT
+#      if (_MSC_VER >= 1400)
+#        define PNG_RESTRICT __restrict
+#      endif
+#    endif
+
+#  elif defined(__WATCOMC__)
+#    ifndef PNG_RESTRICT
+#      define PNG_RESTRICT __restrict
+#    endif
+#  endif
+#endif /* PNG_PEDANTIC_WARNINGS */
+
+#ifndef PNG_DEPRECATED
+#  define PNG_DEPRECATED  /* Use of this function is deprecated */
+#endif
+#ifndef PNG_USE_RESULT
+#  define PNG_USE_RESULT  /* The result of this function must be checked */
+#endif
+#ifndef PNG_NORETURN
+#  define PNG_NORETURN    /* This function does not return */
+#endif
+#ifndef PNG_ALLOCATED
+#  define PNG_ALLOCATED   /* The result of the function is new memory */
+#endif
+#ifndef PNG_PRIVATE
+#  define PNG_PRIVATE     /* This is a private libpng function */
+#endif
+#ifndef PNG_RESTRICT
+#  define PNG_RESTRICT    /* The C99 "restrict" feature */
+#endif
+
+#ifndef PNG_FP_EXPORT     /* A floating point API. */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+#     define PNG_FP_EXPORT(ordinal, type, name, args)\
+         PNG_EXPORT(ordinal, type, name, args);
+#  else                   /* No floating point APIs */
+#     define PNG_FP_EXPORT(ordinal, type, name, args)
+#  endif
+#endif
+#ifndef PNG_FIXED_EXPORT  /* A fixed point API. */
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+#     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
+         PNG_EXPORT(ordinal, type, name, args);
+#  else                   /* No fixed point APIs */
+#     define PNG_FIXED_EXPORT(ordinal, type, name, args)
+#  endif
+#endif
+
+#ifndef PNG_BUILDING_SYMBOL_TABLE
+/* Some typedefs to get us started.  These should be safe on most of the common
+ * platforms.
+ *
+ * png_uint_32 and png_int_32 may, currently, be larger than required to hold a
+ * 32-bit value however this is not normally advisable.
+ *
+ * png_uint_16 and png_int_16 should always be two bytes in size - this is
+ * verified at library build time.
+ *
+ * png_byte must always be one byte in size.
+ *
+ * The checks below use constants from limits.h, as defined by the ISOC90
+ * standard.
+ */
+#if CHAR_BIT == 8 && UCHAR_MAX == 255
+   typedef unsigned char png_byte;
+#else
+#  error "libpng requires 8-bit bytes"
+#endif
+
+#if INT_MIN == -32768 && INT_MAX == 32767
+   typedef int png_int_16;
+#elif SHRT_MIN == -32768 && SHRT_MAX == 32767
+   typedef short png_int_16;
+#else
+#  error "libpng requires a signed 16-bit type"
+#endif
+
+#if UINT_MAX == 65535
+   typedef unsigned int png_uint_16;
+#elif USHRT_MAX == 65535
+   typedef unsigned short png_uint_16;
+#else
+#  error "libpng requires an unsigned 16-bit type"
+#endif
+
+#if INT_MIN < -2147483646 && INT_MAX > 2147483646
+   typedef int png_int_32;
+#elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646
+   typedef long int png_int_32;
+#else
+#  error "libpng requires a signed 32-bit (or more) type"
+#endif
+
+#if UINT_MAX > 4294967294U
+   typedef unsigned int png_uint_32;
+#elif ULONG_MAX > 4294967294U
+   typedef unsigned long int png_uint_32;
+#else
+#  error "libpng requires an unsigned 32-bit (or more) type"
+#endif
+
+/* Prior to 1.6.0, it was possible to disable the use of size_t and ptrdiff_t.
+ * From 1.6.0 onwards, an ISO C90 compiler, as well as a standard-compliant
+ * behavior of sizeof and ptrdiff_t are required.
+ * The legacy typedefs are provided here for backwards compatibility.
+ */
+typedef size_t png_size_t;
+typedef ptrdiff_t png_ptrdiff_t;
+
+/* libpng needs to know the maximum value of 'size_t' and this controls the
+ * definition of png_alloc_size_t, below.  This maximum value of size_t limits
+ * but does not control the maximum allocations the library makes - there is
+ * direct application control of this through png_set_user_limits().
+ */
+#ifndef PNG_SMALL_SIZE_T
+   /* Compiler specific tests for systems where size_t is known to be less than
+    * 32 bits (some of these systems may no longer work because of the lack of
+    * 'far' support; see above.)
+    */
+#  if (defined(__TURBOC__) && !defined(__FLAT__)) ||\
+   (defined(_MSC_VER) && defined(MAXSEG_64K))
+#     define PNG_SMALL_SIZE_T
+#  endif
+#endif
+
+/* png_alloc_size_t is guaranteed to be no smaller than size_t, and no smaller
+ * than png_uint_32.  Casts from size_t or png_uint_32 to png_alloc_size_t are
+ * not necessary; in fact, it is recommended not to use them at all, so that
+ * the compiler can complain when something turns out to be problematic.
+ *
+ * Casts in the other direction (from png_alloc_size_t to size_t or
+ * png_uint_32) should be explicitly applied; however, we do not expect to
+ * encounter practical situations that require such conversions.
+ *
+ * PNG_SMALL_SIZE_T must be defined if the maximum value of size_t is less than
+ * 4294967295 - i.e. less than the maximum value of png_uint_32.
+ */
+#ifdef PNG_SMALL_SIZE_T
+   typedef png_uint_32 png_alloc_size_t;
+#else
+   typedef size_t png_alloc_size_t;
+#endif
+
+/* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler
+ * implementations of Intel CPU specific support of user-mode segmented address
+ * spaces, where 16-bit pointers address more than 65536 bytes of memory using
+ * separate 'segment' registers.  The implementation requires two different
+ * types of pointer (only one of which includes the segment value.)
+ *
+ * If required this support is available in version 1.2 of libpng and may be
+ * available in versions through 1.5, although the correctness of the code has
+ * not been verified recently.
+ */
+
+/* Typedef for floating-point numbers that are converted to fixed-point with a
+ * multiple of 100,000, e.g., gamma
+ */
+typedef png_int_32 png_fixed_point;
+
+/* Add typedefs for pointers */
+typedef void                  * png_voidp;
+typedef const void            * png_const_voidp;
+typedef png_byte              * png_bytep;
+typedef const png_byte        * png_const_bytep;
+typedef png_uint_32           * png_uint_32p;
+typedef const png_uint_32     * png_const_uint_32p;
+typedef png_int_32            * png_int_32p;
+typedef const png_int_32      * png_const_int_32p;
+typedef png_uint_16           * png_uint_16p;
+typedef const png_uint_16     * png_const_uint_16p;
+typedef png_int_16            * png_int_16p;
+typedef const png_int_16      * png_const_int_16p;
+typedef char                  * png_charp;
+typedef const char            * png_const_charp;
+typedef png_fixed_point       * png_fixed_point_p;
+typedef const png_fixed_point * png_const_fixed_point_p;
+typedef size_t                * png_size_tp;
+typedef const size_t          * png_const_size_tp;
+
+#ifdef PNG_STDIO_SUPPORTED
+typedef FILE            * png_FILE_p;
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+typedef double       * png_doublep;
+typedef const double * png_const_doublep;
+#endif
+
+/* Pointers to pointers; i.e. arrays */
+typedef png_byte        * * png_bytepp;
+typedef png_uint_32     * * png_uint_32pp;
+typedef png_int_32      * * png_int_32pp;
+typedef png_uint_16     * * png_uint_16pp;
+typedef png_int_16      * * png_int_16pp;
+typedef const char      * * png_const_charpp;
+typedef char            * * png_charpp;
+typedef png_fixed_point * * png_fixed_point_pp;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+typedef double          * * png_doublepp;
+#endif
+
+/* Pointers to pointers to pointers; i.e., pointer to array */
+typedef char            * * * png_charppp;
+
+#endif /* PNG_BUILDING_SYMBOL_TABLE */
+
+#endif /* PNGCONF_H */
diff --git a/extern/libpng/pngdebug.h b/extern/libpng/pngdebug.h
new file mode 100644
index 0000000000..00d5a4569e
--- /dev/null
+++ b/extern/libpng/pngdebug.h
@@ -0,0 +1,153 @@
+
+/* pngdebug.h - Debugging macros for libpng, also used in pngtest.c
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2013 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Define PNG_DEBUG at compile time for debugging information.  Higher
+ * numbers for PNG_DEBUG mean more debugging information.  This has
+ * only been added since version 0.95 so it is not implemented throughout
+ * libpng yet, but more support will be added as needed.
+ *
+ * png_debug[1-2]?(level, message ,arg{0-2})
+ *   Expands to a statement (either a simple expression or a compound
+ *   do..while(0) statement) that outputs a message with parameter
+ *   substitution if PNG_DEBUG is defined to 2 or more.  If PNG_DEBUG
+ *   is undefined, 0 or 1 every png_debug expands to a simple expression
+ *   (actually ((void)0)).
+ *
+ *   level: level of detail of message, starting at 0.  A level 'n'
+ *          message is preceded by 'n' 3-space indentations (not implemented
+ *          on Microsoft compilers unless PNG_DEBUG_FILE is also
+ *          defined, to allow debug DLL compilation with no standard IO).
+ *   message: a printf(3) style text string.  A trailing '\n' is added
+ *            to the message.
+ *   arg: 0 to 2 arguments for printf(3) style substitution in message.
+ */
+#ifndef PNGDEBUG_H
+#define PNGDEBUG_H
+/* These settings control the formatting of messages in png.c and pngerror.c */
+/* Moved to pngdebug.h at 1.5.0 */
+#  ifndef PNG_LITERAL_SHARP
+#    define PNG_LITERAL_SHARP 0x23
+#  endif
+#  ifndef PNG_LITERAL_LEFT_SQUARE_BRACKET
+#    define PNG_LITERAL_LEFT_SQUARE_BRACKET 0x5b
+#  endif
+#  ifndef PNG_LITERAL_RIGHT_SQUARE_BRACKET
+#    define PNG_LITERAL_RIGHT_SQUARE_BRACKET 0x5d
+#  endif
+#  ifndef PNG_STRING_NEWLINE
+#    define PNG_STRING_NEWLINE "\n"
+#  endif
+
+#ifdef PNG_DEBUG
+#  if (PNG_DEBUG > 0)
+#    if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)
+#      include <crtdbg.h>
+#      if (PNG_DEBUG > 1)
+#        ifndef _DEBUG
+#          define _DEBUG
+#        endif
+#        ifndef png_debug
+#          define png_debug(l,m)  _RPT0(_CRT_WARN,m PNG_STRING_NEWLINE)
+#        endif
+#        ifndef png_debug1
+#          define png_debug1(l,m,p1)  _RPT1(_CRT_WARN,m PNG_STRING_NEWLINE,p1)
+#        endif
+#        ifndef png_debug2
+#          define png_debug2(l,m,p1,p2) \
+             _RPT2(_CRT_WARN,m PNG_STRING_NEWLINE,p1,p2)
+#        endif
+#      endif
+#    else /* PNG_DEBUG_FILE || !_MSC_VER */
+#      ifndef PNG_STDIO_SUPPORTED
+#        include <stdio.h> /* not included yet */
+#      endif
+#      ifndef PNG_DEBUG_FILE
+#        define PNG_DEBUG_FILE stderr
+#      endif /* PNG_DEBUG_FILE */
+
+#      if (PNG_DEBUG > 1)
+#        ifdef __STDC__
+#          ifndef png_debug
+#            define png_debug(l,m) \
+       do { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : "")))); \
+       } while (0)
+#          endif
+#          ifndef png_debug1
+#            define png_debug1(l,m,p1) \
+       do { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : ""))),p1); \
+       } while (0)
+#          endif
+#          ifndef png_debug2
+#            define png_debug2(l,m,p1,p2) \
+       do { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : ""))),p1,p2);\
+       } while (0)
+#          endif
+#        else /* __STDC __ */
+#          ifndef png_debug
+#            define png_debug(l,m) \
+       do { \
+       int num_tabs=l; \
+       char format[256]; \
+       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+         m,PNG_STRING_NEWLINE); \
+       fprintf(PNG_DEBUG_FILE,format); \
+       } while (0)
+#          endif
+#          ifndef png_debug1
+#            define png_debug1(l,m,p1) \
+       do { \
+       int num_tabs=l; \
+       char format[256]; \
+       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+         m,PNG_STRING_NEWLINE); \
+       fprintf(PNG_DEBUG_FILE,format,p1); \
+       } while (0)
+#          endif
+#          ifndef png_debug2
+#            define png_debug2(l,m,p1,p2) \
+       do { \
+       int num_tabs=l; \
+       char format[256]; \
+       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+         m,PNG_STRING_NEWLINE); \
+       fprintf(PNG_DEBUG_FILE,format,p1,p2); \
+       } while (0)
+#          endif
+#        endif /* __STDC __ */
+#      endif /* (PNG_DEBUG > 1) */
+
+#    endif /* _MSC_VER */
+#  endif /* (PNG_DEBUG > 0) */
+#endif /* PNG_DEBUG */
+#ifndef png_debug
+#  define png_debug(l, m) ((void)0)
+#endif
+#ifndef png_debug1
+#  define png_debug1(l, m, p1) ((void)0)
+#endif
+#ifndef png_debug2
+#  define png_debug2(l, m, p1, p2) ((void)0)
+#endif
+#endif /* PNGDEBUG_H */
diff --git a/extern/libpng/pngerror.c b/extern/libpng/pngerror.c
new file mode 100644
index 0000000000..ec3a709b9d
--- /dev/null
+++ b/extern/libpng/pngerror.c
@@ -0,0 +1,963 @@
+
+/* pngerror.c - stub functions for i/o and memory allocation
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all error handling.  Users who
+ * need special error handling are expected to write replacement functions
+ * and use png_set_error_fn() to use those functions.  See the instructions
+ * at each function.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr,
+    png_const_charp error_message)),PNG_NORETURN);
+
+#ifdef PNG_WARNINGS_SUPPORTED
+static void /* PRIVATE */
+png_default_warning PNGARG((png_const_structrp png_ptr,
+    png_const_charp warning_message));
+#endif /* WARNINGS */
+
+/* This function is called whenever there is a fatal error.  This function
+ * should not be changed.  If there is a need to handle errors differently,
+ * you should supply a replacement error function and use png_set_error_fn()
+ * to replace the error function at run-time.
+ */
+#ifdef PNG_ERROR_TEXT_SUPPORTED
+PNG_FUNCTION(void,PNGAPI
+png_error,(png_const_structrp png_ptr, png_const_charp error_message),
+    PNG_NORETURN)
+{
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   char msg[16];
+   if (png_ptr != NULL)
+   {
+      if ((png_ptr->flags &
+         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
+      {
+         if (*error_message == PNG_LITERAL_SHARP)
+         {
+            /* Strip "#nnnn " from beginning of error message. */
+            int offset;
+            for (offset = 1; offset<15; offset++)
+               if (error_message[offset] == ' ')
+                  break;
+
+            if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
+            {
+               int i;
+               for (i = 0; i < offset - 1; i++)
+                  msg[i] = error_message[i + 1];
+               msg[i - 1] = '\0';
+               error_message = msg;
+            }
+
+            else
+               error_message += offset;
+         }
+
+         else
+         {
+            if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
+            {
+               msg[0] = '0';
+               msg[1] = '\0';
+               error_message = msg;
+            }
+         }
+      }
+   }
+#endif
+   if (png_ptr != NULL && png_ptr->error_fn != NULL)
+      (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr),
+          error_message);
+
+   /* If the custom handler doesn't exist, or if it returns,
+      use the default handler, which will not return. */
+   png_default_error(png_ptr, error_message);
+}
+#else
+PNG_FUNCTION(void,PNGAPI
+png_err,(png_const_structrp png_ptr),PNG_NORETURN)
+{
+   /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed
+    * erroneously as '\0', instead of the empty string "".  This was
+    * apparently an error, introduced in libpng-1.2.20, and png_default_error
+    * will crash in this case.
+    */
+   if (png_ptr != NULL && png_ptr->error_fn != NULL)
+      (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), "");
+
+   /* If the custom handler doesn't exist, or if it returns,
+      use the default handler, which will not return. */
+   png_default_error(png_ptr, "");
+}
+#endif /* ERROR_TEXT */
+
+/* Utility to safely appends strings to a buffer.  This never errors out so
+ * error checking is not required in the caller.
+ */
+size_t
+png_safecat(png_charp buffer, size_t bufsize, size_t pos,
+    png_const_charp string)
+{
+   if (buffer != NULL && pos < bufsize)
+   {
+      if (string != NULL)
+         while (*string != '\0' && pos < bufsize-1)
+           buffer[pos++] = *string++;
+
+      buffer[pos] = '\0';
+   }
+
+   return pos;
+}
+
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string.
+ */
+png_charp
+png_format_number(png_const_charp start, png_charp end, int format,
+    png_alloc_size_t number)
+{
+   int count = 0;    /* number of digits output */
+   int mincount = 1; /* minimum number required */
+   int output = 0;   /* digit output (for the fixed point format) */
+
+   *--end = '\0';
+
+   /* This is written so that the loop always runs at least once, even with
+    * number zero.
+    */
+   while (end > start && (number != 0 || count < mincount))
+   {
+
+      static const char digits[] = "0123456789ABCDEF";
+
+      switch (format)
+      {
+         case PNG_NUMBER_FORMAT_fixed:
+            /* Needs five digits (the fraction) */
+            mincount = 5;
+            if (output != 0 || number % 10 != 0)
+            {
+               *--end = digits[number % 10];
+               output = 1;
+            }
+            number /= 10;
+            break;
+
+         case PNG_NUMBER_FORMAT_02u:
+            /* Expects at least 2 digits. */
+            mincount = 2;
+            /* FALLTHROUGH */
+
+         case PNG_NUMBER_FORMAT_u:
+            *--end = digits[number % 10];
+            number /= 10;
+            break;
+
+         case PNG_NUMBER_FORMAT_02x:
+            /* This format expects at least two digits */
+            mincount = 2;
+            /* FALLTHROUGH */
+
+         case PNG_NUMBER_FORMAT_x:
+            *--end = digits[number & 0xf];
+            number >>= 4;
+            break;
+
+         default: /* an error */
+            number = 0;
+            break;
+      }
+
+      /* Keep track of the number of digits added */
+      ++count;
+
+      /* Float a fixed number here: */
+      if ((format == PNG_NUMBER_FORMAT_fixed) && (count == 5) && (end > start))
+      {
+         /* End of the fraction, but maybe nothing was output?  In that case
+          * drop the decimal point.  If the number is a true zero handle that
+          * here.
+          */
+         if (output != 0)
+            *--end = '.';
+         else if (number == 0) /* and !output */
+            *--end = '0';
+      }
+   }
+
+   return end;
+}
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* This function is called whenever there is a non-fatal error.  This function
+ * should not be changed.  If there is a need to handle warnings differently,
+ * you should supply a replacement warning function and use
+ * png_set_error_fn() to replace the warning function at run-time.
+ */
+void PNGAPI
+png_warning(png_const_structrp png_ptr, png_const_charp warning_message)
+{
+   int offset = 0;
+   if (png_ptr != NULL)
+   {
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   if ((png_ptr->flags &
+       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
+#endif
+      {
+         if (*warning_message == PNG_LITERAL_SHARP)
+         {
+            for (offset = 1; offset < 15; offset++)
+               if (warning_message[offset] == ' ')
+                  break;
+         }
+      }
+   }
+   if (png_ptr != NULL && png_ptr->warning_fn != NULL)
+      (*(png_ptr->warning_fn))(png_constcast(png_structrp,png_ptr),
+          warning_message + offset);
+   else
+      png_default_warning(png_ptr, warning_message + offset);
+}
+
+/* These functions support 'formatted' warning messages with up to
+ * PNG_WARNING_PARAMETER_COUNT parameters.  In the format string the parameter
+ * is introduced by @<number>, where 'number' starts at 1.  This follows the
+ * standard established by X/Open for internationalizable error messages.
+ */
+void
+png_warning_parameter(png_warning_parameters p, int number,
+    png_const_charp string)
+{
+   if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT)
+      (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string);
+}
+
+void
+png_warning_parameter_unsigned(png_warning_parameters p, int number, int format,
+    png_alloc_size_t value)
+{
+   char buffer[PNG_NUMBER_BUFFER_SIZE];
+   png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value));
+}
+
+void
+png_warning_parameter_signed(png_warning_parameters p, int number, int format,
+    png_int_32 value)
+{
+   png_alloc_size_t u;
+   png_charp str;
+   char buffer[PNG_NUMBER_BUFFER_SIZE];
+
+   /* Avoid overflow by doing the negate in a png_alloc_size_t: */
+   u = (png_alloc_size_t)value;
+   if (value < 0)
+      u = ~u + 1;
+
+   str = PNG_FORMAT_NUMBER(buffer, format, u);
+
+   if (value < 0 && str > buffer)
+      *--str = '-';
+
+   png_warning_parameter(p, number, str);
+}
+
+void
+png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p,
+    png_const_charp message)
+{
+   /* The internal buffer is just 192 bytes - enough for all our messages,
+    * overflow doesn't happen because this code checks!  If someone figures
+    * out how to send us a message longer than 192 bytes, all that will
+    * happen is that the message will be truncated appropriately.
+    */
+   size_t i = 0; /* Index in the msg[] buffer: */
+   char msg[192];
+
+   /* Each iteration through the following loop writes at most one character
+    * to msg[i++] then returns here to validate that there is still space for
+    * the trailing '\0'.  It may (in the case of a parameter) read more than
+    * one character from message[]; it must check for '\0' and continue to the
+    * test if it finds the end of string.
+    */
+   while (i<(sizeof msg)-1 && *message != '\0')
+   {
+      /* '@' at end of string is now just printed (previously it was skipped);
+       * it is an error in the calling code to terminate the string with @.
+       */
+      if (p != NULL && *message == '@' && message[1] != '\0')
+      {
+         int parameter_char = *++message; /* Consume the '@' */
+         static const char valid_parameters[] = "123456789";
+         int parameter = 0;
+
+         /* Search for the parameter digit, the index in the string is the
+          * parameter to use.
+          */
+         while (valid_parameters[parameter] != parameter_char &&
+            valid_parameters[parameter] != '\0')
+            ++parameter;
+
+         /* If the parameter digit is out of range it will just get printed. */
+         if (parameter < PNG_WARNING_PARAMETER_COUNT)
+         {
+            /* Append this parameter */
+            png_const_charp parm = p[parameter];
+            png_const_charp pend = p[parameter] + (sizeof p[parameter]);
+
+            /* No need to copy the trailing '\0' here, but there is no guarantee
+             * that parm[] has been initialized, so there is no guarantee of a
+             * trailing '\0':
+             */
+            while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend)
+               msg[i++] = *parm++;
+
+            /* Consume the parameter digit too: */
+            ++message;
+            continue;
+         }
+
+         /* else not a parameter and there is a character after the @ sign; just
+          * copy that.  This is known not to be '\0' because of the test above.
+          */
+      }
+
+      /* At this point *message can't be '\0', even in the bad parameter case
+       * above where there is a lone '@' at the end of the message string.
+       */
+      msg[i++] = *message++;
+   }
+
+   /* i is always less than (sizeof msg), so: */
+   msg[i] = '\0';
+
+   /* And this is the formatted message. It may be larger than
+    * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these
+    * are not (currently) formatted.
+    */
+   png_warning(png_ptr, msg);
+}
+#endif /* WARNINGS */
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+void PNGAPI
+png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
+{
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
+   {
+#     ifdef PNG_READ_SUPPORTED
+         if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+            png_ptr->chunk_name != 0)
+            png_chunk_warning(png_ptr, error_message);
+         else
+#     endif
+      png_warning(png_ptr, error_message);
+   }
+
+   else
+   {
+#     ifdef PNG_READ_SUPPORTED
+         if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+            png_ptr->chunk_name != 0)
+            png_chunk_error(png_ptr, error_message);
+         else
+#     endif
+      png_error(png_ptr, error_message);
+   }
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+      PNG_UNUSED(error_message)
+#  endif
+}
+
+void /* PRIVATE */
+png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
+{
+   if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
+      png_warning(png_ptr, error_message);
+   else
+      png_error(png_ptr, error_message);
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+      PNG_UNUSED(error_message)
+#  endif
+}
+
+void /* PRIVATE */
+png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
+{
+   if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
+      png_warning(png_ptr, error_message);
+   else
+      png_error(png_ptr, error_message);
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+      PNG_UNUSED(error_message)
+#  endif
+}
+#endif /* BENIGN_ERRORS */
+
+#define PNG_MAX_ERROR_TEXT 196 /* Currently limited by profile_error in png.c */
+#if defined(PNG_WARNINGS_SUPPORTED) || \
+   (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED))
+/* These utilities are used internally to build an error message that relates
+ * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
+ * which is used to prefix the message.  The message is limited in length
+ * to 63 bytes. The name characters are output as hex digits wrapped in []
+ * if the character is invalid.
+ */
+#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+static const char png_digit[16] = {
+   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+   'A', 'B', 'C', 'D', 'E', 'F'
+};
+
+static void /* PRIVATE */
+png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
+    error_message)
+{
+   png_uint_32 chunk_name = png_ptr->chunk_name;
+   int iout = 0, ishift = 24;
+
+   while (ishift >= 0)
+   {
+      int c = (int)(chunk_name >> ishift) & 0xff;
+
+      ishift -= 8;
+      if (isnonalpha(c) != 0)
+      {
+         buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
+         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
+         buffer[iout++] = png_digit[c & 0x0f];
+         buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET;
+      }
+
+      else
+      {
+         buffer[iout++] = (char)c;
+      }
+   }
+
+   if (error_message == NULL)
+      buffer[iout] = '\0';
+
+   else
+   {
+      int iin = 0;
+
+      buffer[iout++] = ':';
+      buffer[iout++] = ' ';
+
+      while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
+         buffer[iout++] = error_message[iin++];
+
+      /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
+      buffer[iout] = '\0';
+   }
+}
+#endif /* WARNINGS || ERROR_TEXT */
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
+PNG_FUNCTION(void,PNGAPI
+png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message),
+    PNG_NORETURN)
+{
+   char msg[18+PNG_MAX_ERROR_TEXT];
+   if (png_ptr == NULL)
+      png_error(png_ptr, error_message);
+
+   else
+   {
+      png_format_buffer(png_ptr, msg, error_message);
+      png_error(png_ptr, msg);
+   }
+}
+#endif /* READ && ERROR_TEXT */
+
+#ifdef PNG_WARNINGS_SUPPORTED
+void PNGAPI
+png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message)
+{
+   char msg[18+PNG_MAX_ERROR_TEXT];
+   if (png_ptr == NULL)
+      png_warning(png_ptr, warning_message);
+
+   else
+   {
+      png_format_buffer(png_ptr, msg, warning_message);
+      png_warning(png_ptr, msg);
+   }
+}
+#endif /* WARNINGS */
+
+#ifdef PNG_READ_SUPPORTED
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+void PNGAPI
+png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
+    error_message)
+{
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
+      png_chunk_warning(png_ptr, error_message);
+
+   else
+      png_chunk_error(png_ptr, error_message);
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+      PNG_UNUSED(error_message)
+#  endif
+}
+#endif
+#endif /* READ */
+
+void /* PRIVATE */
+png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
+{
+#  ifndef PNG_WARNINGS_SUPPORTED
+      PNG_UNUSED(message)
+#  endif
+
+   /* This is always supported, but for just read or just write it
+    * unconditionally does the right thing.
+    */
+#  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+#  endif
+
+#  ifdef PNG_READ_SUPPORTED
+      {
+         if (error < PNG_CHUNK_ERROR)
+            png_chunk_warning(png_ptr, message);
+
+         else
+            png_chunk_benign_error(png_ptr, message);
+      }
+#  endif
+
+#  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
+      else if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+#  endif
+
+#  ifdef PNG_WRITE_SUPPORTED
+      {
+         if (error < PNG_CHUNK_WRITE_ERROR)
+            png_app_warning(png_ptr, message);
+
+         else
+            png_app_error(png_ptr, message);
+      }
+#  endif
+}
+
+#ifdef PNG_ERROR_TEXT_SUPPORTED
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_FUNCTION(void,
+png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
+{
+#  define fixed_message "fixed point overflow in "
+#  define fixed_message_ln ((sizeof fixed_message)-1)
+   unsigned int  iin;
+   char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
+   memcpy(msg, fixed_message, fixed_message_ln);
+   iin = 0;
+   if (name != NULL)
+      while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
+      {
+         msg[fixed_message_ln + iin] = name[iin];
+         ++iin;
+      }
+   msg[fixed_message_ln + iin] = 0;
+   png_error(png_ptr, msg);
+}
+#endif
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+/* This API only exists if ANSI-C style error handling is used,
+ * otherwise it is necessary for png_default_error to be overridden.
+ */
+jmp_buf* PNGAPI
+png_set_longjmp_fn(png_structrp png_ptr, png_longjmp_ptr longjmp_fn,
+    size_t jmp_buf_size)
+{
+   /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value
+    * and it must not change after that.  Libpng doesn't care how big the
+    * buffer is, just that it doesn't change.
+    *
+    * If the buffer size is no *larger* than the size of jmp_buf when libpng is
+    * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0
+    * semantics that this call will not fail.  If the size is larger, however,
+    * the buffer is allocated and this may fail, causing the function to return
+    * NULL.
+    */
+   if (png_ptr == NULL)
+      return NULL;
+
+   if (png_ptr->jmp_buf_ptr == NULL)
+   {
+      png_ptr->jmp_buf_size = 0; /* not allocated */
+
+      if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local))
+         png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local;
+
+      else
+      {
+         png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *,
+             png_malloc_warn(png_ptr, jmp_buf_size));
+
+         if (png_ptr->jmp_buf_ptr == NULL)
+            return NULL; /* new NULL return on OOM */
+
+         png_ptr->jmp_buf_size = jmp_buf_size;
+      }
+   }
+
+   else /* Already allocated: check the size */
+   {
+      size_t size = png_ptr->jmp_buf_size;
+
+      if (size == 0)
+      {
+         size = (sizeof png_ptr->jmp_buf_local);
+         if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local)
+         {
+            /* This is an internal error in libpng: somehow we have been left
+             * with a stack allocated jmp_buf when the application regained
+             * control.  It's always possible to fix this up, but for the moment
+             * this is a png_error because that makes it easy to detect.
+             */
+            png_error(png_ptr, "Libpng jmp_buf still allocated");
+            /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */
+         }
+      }
+
+      if (size != jmp_buf_size)
+      {
+         png_warning(png_ptr, "Application jmp_buf size changed");
+         return NULL; /* caller will probably crash: no choice here */
+      }
+   }
+
+   /* Finally fill in the function, now we have a satisfactory buffer. It is
+    * valid to change the function on every call.
+    */
+   png_ptr->longjmp_fn = longjmp_fn;
+   return png_ptr->jmp_buf_ptr;
+}
+
+void /* PRIVATE */
+png_free_jmpbuf(png_structrp png_ptr)
+{
+   if (png_ptr != NULL)
+   {
+      jmp_buf *jb = png_ptr->jmp_buf_ptr;
+
+      /* A size of 0 is used to indicate a local, stack, allocation of the
+       * pointer; used here and in png.c
+       */
+      if (jb != NULL && png_ptr->jmp_buf_size > 0)
+      {
+
+         /* This stuff is so that a failure to free the error control structure
+          * does not leave libpng in a state with no valid error handling: the
+          * free always succeeds, if there is an error it gets ignored.
+          */
+         if (jb != &png_ptr->jmp_buf_local)
+         {
+            /* Make an internal, libpng, jmp_buf to return here */
+            jmp_buf free_jmp_buf;
+
+            if (!setjmp(free_jmp_buf))
+            {
+               png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */
+               png_ptr->jmp_buf_size = 0; /* stack allocation */
+               png_ptr->longjmp_fn = longjmp;
+               png_free(png_ptr, jb); /* Return to setjmp on error */
+            }
+         }
+      }
+
+      /* *Always* cancel everything out: */
+      png_ptr->jmp_buf_size = 0;
+      png_ptr->jmp_buf_ptr = NULL;
+      png_ptr->longjmp_fn = 0;
+   }
+}
+#endif
+
+/* This is the default error handling function.  Note that replacements for
+ * this function MUST NOT RETURN, or the program will likely crash.  This
+ * function is used by default, or if the program supplies NULL for the
+ * error function pointer in png_set_error_fn().
+ */
+static PNG_FUNCTION(void /* PRIVATE */,
+png_default_error,(png_const_structrp png_ptr, png_const_charp error_message),
+    PNG_NORETURN)
+{
+#ifdef PNG_CONSOLE_IO_SUPPORTED
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   /* Check on NULL only added in 1.5.4 */
+   if (error_message != NULL && *error_message == PNG_LITERAL_SHARP)
+   {
+      /* Strip "#nnnn " from beginning of error message. */
+      int offset;
+      char error_number[16];
+      for (offset = 0; offset<15; offset++)
+      {
+         error_number[offset] = error_message[offset + 1];
+         if (error_message[offset] == ' ')
+            break;
+      }
+
+      if ((offset > 1) && (offset < 15))
+      {
+         error_number[offset - 1] = '\0';
+         fprintf(stderr, "libpng error no. %s: %s",
+             error_number, error_message + offset + 1);
+         fprintf(stderr, PNG_STRING_NEWLINE);
+      }
+
+      else
+      {
+         fprintf(stderr, "libpng error: %s, offset=%d",
+             error_message, offset);
+         fprintf(stderr, PNG_STRING_NEWLINE);
+      }
+   }
+   else
+#endif
+   {
+      fprintf(stderr, "libpng error: %s", error_message ? error_message :
+         "undefined");
+      fprintf(stderr, PNG_STRING_NEWLINE);
+   }
+#else
+   PNG_UNUSED(error_message) /* Make compiler happy */
+#endif
+   png_longjmp(png_ptr, 1);
+}
+
+PNG_FUNCTION(void,PNGAPI
+png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
+{
+#ifdef PNG_SETJMP_SUPPORTED
+   if (png_ptr != NULL && png_ptr->longjmp_fn != NULL &&
+       png_ptr->jmp_buf_ptr != NULL)
+      png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(val)
+#endif
+
+   /* If control reaches this point, png_longjmp() must not return. The only
+    * choice is to terminate the whole process (or maybe the thread); to do
+    * this the ANSI-C abort() function is used unless a different method is
+    * implemented by overriding the default configuration setting for
+    * PNG_ABORT().
+    */
+   PNG_ABORT();
+}
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* This function is called when there is a warning, but the library thinks
+ * it can continue anyway.  Replacement functions don't have to do anything
+ * here if you don't want them to.  In the default configuration, png_ptr is
+ * not used, but it is passed in case it may be useful.
+ */
+static void /* PRIVATE */
+png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message)
+{
+#ifdef PNG_CONSOLE_IO_SUPPORTED
+#  ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   if (*warning_message == PNG_LITERAL_SHARP)
+   {
+      int offset;
+      char warning_number[16];
+      for (offset = 0; offset < 15; offset++)
+      {
+         warning_number[offset] = warning_message[offset + 1];
+         if (warning_message[offset] == ' ')
+            break;
+      }
+
+      if ((offset > 1) && (offset < 15))
+      {
+         warning_number[offset + 1] = '\0';
+         fprintf(stderr, "libpng warning no. %s: %s",
+             warning_number, warning_message + offset);
+         fprintf(stderr, PNG_STRING_NEWLINE);
+      }
+
+      else
+      {
+         fprintf(stderr, "libpng warning: %s",
+             warning_message);
+         fprintf(stderr, PNG_STRING_NEWLINE);
+      }
+   }
+   else
+#  endif
+
+   {
+      fprintf(stderr, "libpng warning: %s", warning_message);
+      fprintf(stderr, PNG_STRING_NEWLINE);
+   }
+#else
+   PNG_UNUSED(warning_message) /* Make compiler happy */
+#endif
+   PNG_UNUSED(png_ptr) /* Make compiler happy */
+}
+#endif /* WARNINGS */
+
+/* This function is called when the application wants to use another method
+ * of handling errors and warnings.  Note that the error function MUST NOT
+ * return to the calling routine or serious problems will occur.  The return
+ * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1)
+ */
+void PNGAPI
+png_set_error_fn(png_structrp png_ptr, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warning_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->error_ptr = error_ptr;
+   png_ptr->error_fn = error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
+   png_ptr->warning_fn = warning_fn;
+#else
+   PNG_UNUSED(warning_fn)
+#endif
+}
+
+
+/* This function returns a pointer to the error_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_error_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return NULL;
+
+   return ((png_voidp)png_ptr->error_ptr);
+}
+
+
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+void PNGAPI
+png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode)
+{
+   if (png_ptr != NULL)
+   {
+      png_ptr->flags &=
+         ((~(PNG_FLAG_STRIP_ERROR_NUMBERS |
+         PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
+   }
+}
+#endif
+
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+   /* Currently the above both depend on SETJMP_SUPPORTED, however it would be
+    * possible to implement without setjmp support just so long as there is some
+    * way to handle the error return here:
+    */
+PNG_FUNCTION(void /* PRIVATE */, (PNGCBAPI
+png_safe_error),(png_structp png_nonconst_ptr, png_const_charp error_message),
+    PNG_NORETURN)
+{
+   png_const_structrp png_ptr = png_nonconst_ptr;
+   png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
+
+   /* An error is always logged here, overwriting anything (typically a warning)
+    * that is already there:
+    */
+   if (image != NULL)
+   {
+      png_safecat(image->message, (sizeof image->message), 0, error_message);
+      image->warning_or_error |= PNG_IMAGE_ERROR;
+
+      /* Retrieve the jmp_buf from within the png_control, making this work for
+       * C++ compilation too is pretty tricky: C++ wants a pointer to the first
+       * element of a jmp_buf, but C doesn't tell us the type of that.
+       */
+      if (image->opaque != NULL && image->opaque->error_buf != NULL)
+         longjmp(png_control_jmp_buf(image->opaque), 1);
+
+      /* Missing longjmp buffer, the following is to help debugging: */
+      {
+         size_t pos = png_safecat(image->message, (sizeof image->message), 0,
+             "bad longjmp: ");
+         png_safecat(image->message, (sizeof image->message), pos,
+             error_message);
+      }
+   }
+
+   /* Here on an internal programming error. */
+   abort();
+}
+
+#ifdef PNG_WARNINGS_SUPPORTED
+void /* PRIVATE */ PNGCBAPI
+png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message)
+{
+   png_const_structrp png_ptr = png_nonconst_ptr;
+   png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
+
+   /* A warning is only logged if there is no prior warning or error. */
+   if (image->warning_or_error == 0)
+   {
+      png_safecat(image->message, (sizeof image->message), 0, warning_message);
+      image->warning_or_error |= PNG_IMAGE_WARNING;
+   }
+}
+#endif
+
+int /* PRIVATE */
+png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg)
+{
+   volatile png_imagep image = image_in;
+   volatile int result;
+   volatile png_voidp saved_error_buf;
+   jmp_buf safe_jmpbuf;
+
+   /* Safely execute function(arg) with png_error returning to this function. */
+   saved_error_buf = image->opaque->error_buf;
+   result = setjmp(safe_jmpbuf) == 0;
+
+   if (result != 0)
+   {
+
+      image->opaque->error_buf = safe_jmpbuf;
+      result = function(arg);
+   }
+
+   image->opaque->error_buf = saved_error_buf;
+
+   /* And do the cleanup prior to any failure return. */
+   if (result == 0)
+      png_image_free(image);
+
+   return result;
+}
+#endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */
+#endif /* READ || WRITE */
diff --git a/extern/libpng/pngget.c b/extern/libpng/pngget.c
new file mode 100644
index 0000000000..5abf1efd9f
--- /dev/null
+++ b/extern/libpng/pngget.c
@@ -0,0 +1,1249 @@
+
+/* pngget.c - retrieval of values from info struct
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+png_uint_32 PNGAPI
+png_get_valid(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 flag)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->valid & flag);
+
+   return(0);
+}
+
+size_t PNGAPI
+png_get_rowbytes(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->rowbytes);
+
+   return(0);
+}
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+png_bytepp PNGAPI
+png_get_rows(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->row_pointers);
+
+   return(0);
+}
+#endif
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+/* Easy access to info, added in libpng-0.99 */
+png_uint_32 PNGAPI
+png_get_image_width(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->width;
+
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_image_height(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->height;
+
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_bit_depth(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->bit_depth;
+
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_color_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->color_type;
+
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_filter_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->filter_type;
+
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_interlace_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->interlace_type;
+
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_compression_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->compression_type;
+
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
+   info_ptr)
+{
+#ifdef PNG_pHYs_SUPPORTED
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+      {
+         png_debug1(1, "in %s retrieval function",
+             "png_get_x_pixels_per_meter");
+
+         if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
+            return (info_ptr->x_pixels_per_unit);
+      }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
+    info_ptr)
+{
+#ifdef PNG_pHYs_SUPPORTED
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      png_debug1(1, "in %s retrieval function",
+          "png_get_y_pixels_per_meter");
+
+      if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
+         return (info_ptr->y_pixels_per_unit);
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_pHYs_SUPPORTED
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "png_get_pixels_per_meter");
+
+      if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER &&
+          info_ptr->x_pixels_per_unit == info_ptr->y_pixels_per_unit)
+         return (info_ptr->x_pixels_per_unit);
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return (0);
+}
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_pixel_aspect_ratio(png_const_structrp png_ptr, png_const_inforp
+   info_ptr)
+{
+#ifdef PNG_READ_pHYs_SUPPORTED
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio");
+
+      if (info_ptr->x_pixels_per_unit != 0)
+         return ((float)((float)info_ptr->y_pixels_per_unit
+             /(float)info_ptr->x_pixels_per_unit));
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return ((float)0.0);
+}
+#endif
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_fixed_point PNGAPI
+png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr,
+    png_const_inforp info_ptr)
+{
+#ifdef PNG_READ_pHYs_SUPPORTED
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0 &&
+       info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0 &&
+       info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX &&
+       info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
+   {
+      png_fixed_point res;
+
+      png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio_fixed");
+
+      /* The following casts work because a PNG 4 byte integer only has a valid
+       * range of 0..2^31-1; otherwise the cast might overflow.
+       */
+      if (png_muldiv(&res, (png_int_32)info_ptr->y_pixels_per_unit, PNG_FP_1,
+          (png_int_32)info_ptr->x_pixels_per_unit) != 0)
+         return res;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return 0;
+}
+#endif
+
+png_int_32 PNGAPI
+png_get_x_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns");
+
+      if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
+         return (info_ptr->x_offset);
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return (0);
+}
+
+png_int_32 PNGAPI
+png_get_y_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "png_get_y_offset_microns");
+
+      if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
+         return (info_ptr->y_offset);
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return (0);
+}
+
+png_int_32 PNGAPI
+png_get_x_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "png_get_x_offset_pixels");
+
+      if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
+         return (info_ptr->x_offset);
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return (0);
+}
+
+png_int_32 PNGAPI
+png_get_y_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "png_get_y_offset_pixels");
+
+      if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
+         return (info_ptr->y_offset);
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return (0);
+}
+
+#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
+static png_uint_32
+ppi_from_ppm(png_uint_32 ppm)
+{
+#if 0
+   /* The conversion is *(2.54/100), in binary (32 digits):
+    * .00000110100000001001110101001001
+    */
+   png_uint_32 t1001, t1101;
+   ppm >>= 1;                  /* .1 */
+   t1001 = ppm + (ppm >> 3);   /* .1001 */
+   t1101 = t1001 + (ppm >> 1); /* .1101 */
+   ppm >>= 20;                 /* .000000000000000000001 */
+   t1101 += t1101 >> 15;       /* .1101000000000001101 */
+   t1001 >>= 11;               /* .000000000001001 */
+   t1001 += t1001 >> 12;       /* .000000000001001000000001001 */
+   ppm += t1001;               /* .000000000001001000001001001 */
+   ppm += t1101;               /* .110100000001001110101001001 */
+   return (ppm + 16) >> 5;/* .00000110100000001001110101001001 */
+#else
+   /* The argument is a PNG unsigned integer, so it is not permitted
+    * to be bigger than 2^31.
+    */
+   png_fixed_point result;
+   if (ppm <= PNG_UINT_31_MAX && png_muldiv(&result, (png_int_32)ppm, 127,
+       5000) != 0)
+      return (png_uint_32)result;
+
+   /* Overflow. */
+   return 0;
+#endif
+}
+
+png_uint_32 PNGAPI
+png_get_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   return ppi_from_ppm(png_get_pixels_per_meter(png_ptr, info_ptr));
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   return ppi_from_ppm(png_get_x_pixels_per_meter(png_ptr, info_ptr));
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   return ppi_from_ppm(png_get_y_pixels_per_meter(png_ptr, info_ptr));
+}
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+static png_fixed_point
+png_fixed_inches_from_microns(png_const_structrp png_ptr, png_int_32 microns)
+{
+   /* Convert from meters * 1,000,000 to inches * 100,000, meters to
+    * inches is simply *(100/2.54), so we want *(10/2.54) == 500/127.
+    * Notice that this can overflow - a warning is output and 0 is
+    * returned.
+    */
+   return png_muldiv_warn(png_ptr, microns, 500, 127);
+}
+
+png_fixed_point PNGAPI
+png_get_x_offset_inches_fixed(png_const_structrp png_ptr,
+    png_const_inforp info_ptr)
+{
+   return png_fixed_inches_from_microns(png_ptr,
+       png_get_x_offset_microns(png_ptr, info_ptr));
+}
+#endif
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_fixed_point PNGAPI
+png_get_y_offset_inches_fixed(png_const_structrp png_ptr,
+    png_const_inforp info_ptr)
+{
+   return png_fixed_inches_from_microns(png_ptr,
+       png_get_y_offset_microns(png_ptr, info_ptr));
+}
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_x_offset_inches(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   /* To avoid the overflow do the conversion directly in floating
+    * point.
+    */
+   return (float)(png_get_x_offset_microns(png_ptr, info_ptr) * .00003937);
+}
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_y_offset_inches(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   /* To avoid the overflow do the conversion directly in floating
+    * point.
+    */
+   return (float)(png_get_y_offset_microns(png_ptr, info_ptr) * .00003937);
+}
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+png_uint_32 PNGAPI
+png_get_pHYs_dpi(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
+{
+   png_uint_32 retval = 0;
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "pHYs");
+
+      if (res_x != NULL)
+      {
+         *res_x = info_ptr->x_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+
+      if (res_y != NULL)
+      {
+         *res_y = info_ptr->y_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+
+      if (unit_type != NULL)
+      {
+         *unit_type = (int)info_ptr->phys_unit_type;
+         retval |= PNG_INFO_pHYs;
+
+         if (*unit_type == 1)
+         {
+            if (res_x != NULL) *res_x = (png_uint_32)(*res_x * .0254 + .50);
+            if (res_y != NULL) *res_y = (png_uint_32)(*res_y * .0254 + .50);
+         }
+      }
+   }
+
+   return (retval);
+}
+#endif /* pHYs */
+#endif /* INCH_CONVERSIONS */
+
+/* png_get_channels really belongs in here, too, but it's been around longer */
+
+#endif /* EASY_ACCESS */
+
+
+png_byte PNGAPI
+png_get_channels(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->channels);
+
+   return (0);
+}
+
+#ifdef PNG_READ_SUPPORTED
+png_const_bytep PNGAPI
+png_get_signature(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->signature);
+
+   return (NULL);
+}
+#endif
+
+#ifdef PNG_bKGD_SUPPORTED
+png_uint_32 PNGAPI
+png_get_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_color_16p *background)
+{
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_bKGD) != 0 &&
+       background != NULL)
+   {
+      png_debug1(1, "in %s retrieval function", "bKGD");
+
+      *background = &(info_ptr->background);
+      return (PNG_INFO_bKGD);
+   }
+
+   return (0);
+}
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+/* The XYZ APIs were added in 1.5.5 to take advantage of the code added at the
+ * same time to correct the rgb grayscale coefficient defaults obtained from the
+ * cHRM chunk in 1.5.4
+ */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cHRM(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    double *white_x, double *white_y, double *red_x, double *red_y,
+    double *green_x, double *green_y, double *blue_x, double *blue_y)
+{
+   /* Quiet API change: this code used to only return the end points if a cHRM
+    * chunk was present, but the end points can also come from iCCP or sRGB
+    * chunks, so in 1.6.0 the png_get_ APIs return the end points regardless and
+    * the png_set_ APIs merely check that set end points are mutually
+    * consistent.
+    */
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "cHRM");
+
+      if (white_x != NULL)
+         *white_x = png_float(png_ptr,
+             info_ptr->colorspace.end_points_xy.whitex, "cHRM white X");
+      if (white_y != NULL)
+         *white_y = png_float(png_ptr,
+             info_ptr->colorspace.end_points_xy.whitey, "cHRM white Y");
+      if (red_x != NULL)
+         *red_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redx,
+             "cHRM red X");
+      if (red_y != NULL)
+         *red_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redy,
+             "cHRM red Y");
+      if (green_x != NULL)
+         *green_x = png_float(png_ptr,
+             info_ptr->colorspace.end_points_xy.greenx, "cHRM green X");
+      if (green_y != NULL)
+         *green_y = png_float(png_ptr,
+             info_ptr->colorspace.end_points_xy.greeny, "cHRM green Y");
+      if (blue_x != NULL)
+         *blue_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluex,
+             "cHRM blue X");
+      if (blue_y != NULL)
+         *blue_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluey,
+             "cHRM blue Y");
+      return (PNG_INFO_cHRM);
+   }
+
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_cHRM_XYZ(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    double *red_X, double *red_Y, double *red_Z, double *green_X,
+    double *green_Y, double *green_Z, double *blue_X, double *blue_Y,
+    double *blue_Z)
+{
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "cHRM_XYZ(float)");
+
+      if (red_X != NULL)
+         *red_X = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_X,
+             "cHRM red X");
+      if (red_Y != NULL)
+         *red_Y = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Y,
+             "cHRM red Y");
+      if (red_Z != NULL)
+         *red_Z = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Z,
+             "cHRM red Z");
+      if (green_X != NULL)
+         *green_X = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.green_X, "cHRM green X");
+      if (green_Y != NULL)
+         *green_Y = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.green_Y, "cHRM green Y");
+      if (green_Z != NULL)
+         *green_Z = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.green_Z, "cHRM green Z");
+      if (blue_X != NULL)
+         *blue_X = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.blue_X, "cHRM blue X");
+      if (blue_Y != NULL)
+         *blue_Y = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.blue_Y, "cHRM blue Y");
+      if (blue_Z != NULL)
+         *blue_Z = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.blue_Z, "cHRM blue Z");
+      return (PNG_INFO_cHRM);
+   }
+
+   return (0);
+}
+#  endif
+
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
+    png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
+    png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
+    png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
+    png_fixed_point *int_blue_Z)
+{
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "cHRM_XYZ");
+
+      if (int_red_X != NULL)
+         *int_red_X = info_ptr->colorspace.end_points_XYZ.red_X;
+      if (int_red_Y != NULL)
+         *int_red_Y = info_ptr->colorspace.end_points_XYZ.red_Y;
+      if (int_red_Z != NULL)
+         *int_red_Z = info_ptr->colorspace.end_points_XYZ.red_Z;
+      if (int_green_X != NULL)
+         *int_green_X = info_ptr->colorspace.end_points_XYZ.green_X;
+      if (int_green_Y != NULL)
+         *int_green_Y = info_ptr->colorspace.end_points_XYZ.green_Y;
+      if (int_green_Z != NULL)
+         *int_green_Z = info_ptr->colorspace.end_points_XYZ.green_Z;
+      if (int_blue_X != NULL)
+         *int_blue_X = info_ptr->colorspace.end_points_XYZ.blue_X;
+      if (int_blue_Y != NULL)
+         *int_blue_Y = info_ptr->colorspace.end_points_XYZ.blue_Y;
+      if (int_blue_Z != NULL)
+         *int_blue_Z = info_ptr->colorspace.end_points_XYZ.blue_Z;
+      return (PNG_INFO_cHRM);
+   }
+
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_cHRM_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *white_x, png_fixed_point *white_y, png_fixed_point *red_x,
+    png_fixed_point *red_y, png_fixed_point *green_x, png_fixed_point *green_y,
+    png_fixed_point *blue_x, png_fixed_point *blue_y)
+{
+   png_debug1(1, "in %s retrieval function", "cHRM");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      if (white_x != NULL)
+         *white_x = info_ptr->colorspace.end_points_xy.whitex;
+      if (white_y != NULL)
+         *white_y = info_ptr->colorspace.end_points_xy.whitey;
+      if (red_x != NULL)
+         *red_x = info_ptr->colorspace.end_points_xy.redx;
+      if (red_y != NULL)
+         *red_y = info_ptr->colorspace.end_points_xy.redy;
+      if (green_x != NULL)
+         *green_x = info_ptr->colorspace.end_points_xy.greenx;
+      if (green_y != NULL)
+         *green_y = info_ptr->colorspace.end_points_xy.greeny;
+      if (blue_x != NULL)
+         *blue_x = info_ptr->colorspace.end_points_xy.bluex;
+      if (blue_y != NULL)
+         *blue_y = info_ptr->colorspace.end_points_xy.bluey;
+      return (PNG_INFO_cHRM);
+   }
+
+   return (0);
+}
+#  endif
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_gAMA_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *file_gamma)
+{
+   png_debug1(1, "in %s retrieval function", "gAMA");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+       file_gamma != NULL)
+   {
+      *file_gamma = info_ptr->colorspace.gamma;
+      return (PNG_INFO_gAMA);
+   }
+
+   return (0);
+}
+#  endif
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_gAMA(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    double *file_gamma)
+{
+   png_debug1(1, "in %s retrieval function", "gAMA(float)");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+      file_gamma != NULL)
+   {
+      *file_gamma = png_float(png_ptr, info_ptr->colorspace.gamma,
+          "png_get_gAMA");
+      return (PNG_INFO_gAMA);
+   }
+
+   return (0);
+}
+#  endif
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sRGB(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    int *file_srgb_intent)
+{
+   png_debug1(1, "in %s retrieval function", "sRGB");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->valid & PNG_INFO_sRGB) != 0 && file_srgb_intent != NULL)
+   {
+      *file_srgb_intent = info_ptr->colorspace.rendering_intent;
+      return (PNG_INFO_sRGB);
+   }
+
+   return (0);
+}
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+png_uint_32 PNGAPI
+png_get_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_charpp name, int *compression_type,
+    png_bytepp profile, png_uint_32 *proflen)
+{
+   png_debug1(1, "in %s retrieval function", "iCCP");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_iCCP) != 0 &&
+       name != NULL && profile != NULL && proflen != NULL)
+   {
+      *name = info_ptr->iccp_name;
+      *profile = info_ptr->iccp_profile;
+      *proflen = png_get_uint_32(info_ptr->iccp_profile);
+      /* This is somewhat irrelevant since the profile data returned has
+       * actually been uncompressed.
+       */
+      if (compression_type != NULL)
+         *compression_type = PNG_COMPRESSION_TYPE_BASE;
+      return (PNG_INFO_iCCP);
+   }
+
+   return (0);
+
+}
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+int PNGAPI
+png_get_sPLT(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_sPLT_tpp spalettes)
+{
+   if (png_ptr != NULL && info_ptr != NULL && spalettes != NULL)
+   {
+      *spalettes = info_ptr->splt_palettes;
+      return info_ptr->splt_palettes_num;
+   }
+
+   return (0);
+}
+#endif
+
+#ifdef PNG_eXIf_SUPPORTED
+png_uint_32 PNGAPI
+png_get_eXIf(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_bytep *exif)
+{
+  png_warning(png_ptr, "png_get_eXIf does not work; use png_get_eXIf_1");
+  PNG_UNUSED(info_ptr)
+  PNG_UNUSED(exif)
+  return 0;
+}
+
+png_uint_32 PNGAPI
+png_get_eXIf_1(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 *num_exif, png_bytep *exif)
+{
+   png_debug1(1, "in %s retrieval function", "eXIf");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_eXIf) != 0 && exif != NULL)
+   {
+      *num_exif = info_ptr->num_exif;
+      *exif = info_ptr->exif;
+      return (PNG_INFO_eXIf);
+   }
+
+   return (0);
+}
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+png_uint_32 PNGAPI
+png_get_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_uint_16p *hist)
+{
+   png_debug1(1, "in %s retrieval function", "hIST");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_hIST) != 0 && hist != NULL)
+   {
+      *hist = info_ptr->hist;
+      return (PNG_INFO_hIST);
+   }
+
+   return (0);
+}
+#endif
+
+png_uint_32 PNGAPI
+png_get_IHDR(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 *width, png_uint_32 *height, int *bit_depth,
+    int *color_type, int *interlace_type, int *compression_type,
+    int *filter_type)
+{
+   png_debug1(1, "in %s retrieval function", "IHDR");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return (0);
+
+   if (width != NULL)
+       *width = info_ptr->width;
+
+   if (height != NULL)
+       *height = info_ptr->height;
+
+   if (bit_depth != NULL)
+       *bit_depth = info_ptr->bit_depth;
+
+   if (color_type != NULL)
+       *color_type = info_ptr->color_type;
+
+   if (compression_type != NULL)
+      *compression_type = info_ptr->compression_type;
+
+   if (filter_type != NULL)
+      *filter_type = info_ptr->filter_type;
+
+   if (interlace_type != NULL)
+      *interlace_type = info_ptr->interlace_type;
+
+   /* This is redundant if we can be sure that the info_ptr values were all
+    * assigned in png_set_IHDR().  We do the check anyhow in case an
+    * application has ignored our advice not to mess with the members
+    * of info_ptr directly.
+    */
+   png_check_IHDR(png_ptr, info_ptr->width, info_ptr->height,
+       info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
+       info_ptr->compression_type, info_ptr->filter_type);
+
+   return (1);
+}
+
+#ifdef PNG_oFFs_SUPPORTED
+png_uint_32 PNGAPI
+png_get_oFFs(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type)
+{
+   png_debug1(1, "in %s retrieval function", "oFFs");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0 &&
+       offset_x != NULL && offset_y != NULL && unit_type != NULL)
+   {
+      *offset_x = info_ptr->x_offset;
+      *offset_y = info_ptr->y_offset;
+      *unit_type = (int)info_ptr->offset_unit_type;
+      return (PNG_INFO_oFFs);
+   }
+
+   return (0);
+}
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+png_uint_32 PNGAPI
+png_get_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type, int *nparams,
+    png_charp *units, png_charpp *params)
+{
+   png_debug1(1, "in %s retrieval function", "pCAL");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pCAL) != 0 &&
+       purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+       nparams != NULL && units != NULL && params != NULL)
+   {
+      *purpose = info_ptr->pcal_purpose;
+      *X0 = info_ptr->pcal_X0;
+      *X1 = info_ptr->pcal_X1;
+      *type = (int)info_ptr->pcal_type;
+      *nparams = (int)info_ptr->pcal_nparams;
+      *units = info_ptr->pcal_units;
+      *params = info_ptr->pcal_params;
+      return (PNG_INFO_pCAL);
+   }
+
+   return (0);
+}
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+#    if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+         defined(PNG_FLOATING_POINT_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    int *unit, png_fixed_point *width, png_fixed_point *height)
+{
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
+   {
+      *unit = info_ptr->scal_unit;
+      /*TODO: make this work without FP support; the API is currently eliminated
+       * if neither floating point APIs nor internal floating point arithmetic
+       * are enabled.
+       */
+      *width = png_fixed(png_ptr, atof(info_ptr->scal_s_width), "sCAL width");
+      *height = png_fixed(png_ptr, atof(info_ptr->scal_s_height),
+          "sCAL height");
+      return (PNG_INFO_sCAL);
+   }
+
+   return(0);
+}
+#    endif /* FLOATING_ARITHMETIC */
+#  endif /* FIXED_POINT */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    int *unit, double *width, double *height)
+{
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
+   {
+      *unit = info_ptr->scal_unit;
+      *width = atof(info_ptr->scal_s_width);
+      *height = atof(info_ptr->scal_s_height);
+      return (PNG_INFO_sCAL);
+   }
+
+   return(0);
+}
+#  endif /* FLOATING POINT */
+png_uint_32 PNGAPI
+png_get_sCAL_s(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    int *unit, png_charpp width, png_charpp height)
+{
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
+   {
+      *unit = info_ptr->scal_unit;
+      *width = info_ptr->scal_s_width;
+      *height = info_ptr->scal_s_height;
+      return (PNG_INFO_sCAL);
+   }
+
+   return(0);
+}
+#endif /* sCAL */
+
+#ifdef PNG_pHYs_SUPPORTED
+png_uint_32 PNGAPI
+png_get_pHYs(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
+{
+   png_uint_32 retval = 0;
+
+   png_debug1(1, "in %s retrieval function", "pHYs");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      if (res_x != NULL)
+      {
+         *res_x = info_ptr->x_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+
+      if (res_y != NULL)
+      {
+         *res_y = info_ptr->y_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+
+      if (unit_type != NULL)
+      {
+         *unit_type = (int)info_ptr->phys_unit_type;
+         retval |= PNG_INFO_pHYs;
+      }
+   }
+
+   return (retval);
+}
+#endif /* pHYs */
+
+png_uint_32 PNGAPI
+png_get_PLTE(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_colorp *palette, int *num_palette)
+{
+   png_debug1(1, "in %s retrieval function", "PLTE");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_PLTE) != 0 && palette != NULL)
+   {
+      *palette = info_ptr->palette;
+      *num_palette = info_ptr->num_palette;
+      png_debug1(3, "num_palette = %d", *num_palette);
+      return (PNG_INFO_PLTE);
+   }
+
+   return (0);
+}
+
+#ifdef PNG_sBIT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_color_8p *sig_bit)
+{
+   png_debug1(1, "in %s retrieval function", "sBIT");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sBIT) != 0 && sig_bit != NULL)
+   {
+      *sig_bit = &(info_ptr->sig_bit);
+      return (PNG_INFO_sBIT);
+   }
+
+   return (0);
+}
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+int PNGAPI
+png_get_text(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_textp *text_ptr, int *num_text)
+{
+   if (png_ptr != NULL && info_ptr != NULL && info_ptr->num_text > 0)
+   {
+      png_debug1(1, "in 0x%lx retrieval function",
+         (unsigned long)png_ptr->chunk_name);
+
+      if (text_ptr != NULL)
+         *text_ptr = info_ptr->text;
+
+      if (num_text != NULL)
+         *num_text = info_ptr->num_text;
+
+      return info_ptr->num_text;
+   }
+
+   if (num_text != NULL)
+      *num_text = 0;
+
+   return(0);
+}
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+png_uint_32 PNGAPI
+png_get_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_timep *mod_time)
+{
+   png_debug1(1, "in %s retrieval function", "tIME");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tIME) != 0 && mod_time != NULL)
+   {
+      *mod_time = &(info_ptr->mod_time);
+      return (PNG_INFO_tIME);
+   }
+
+   return (0);
+}
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+png_uint_32 PNGAPI
+png_get_tRNS(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color)
+{
+   png_uint_32 retval = 0;
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tRNS) != 0)
+   {
+      png_debug1(1, "in %s retrieval function", "tRNS");
+
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         if (trans_alpha != NULL)
+         {
+            *trans_alpha = info_ptr->trans_alpha;
+            retval |= PNG_INFO_tRNS;
+         }
+
+         if (trans_color != NULL)
+            *trans_color = &(info_ptr->trans_color);
+      }
+
+      else /* if (info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) */
+      {
+         if (trans_color != NULL)
+         {
+            *trans_color = &(info_ptr->trans_color);
+            retval |= PNG_INFO_tRNS;
+         }
+
+         if (trans_alpha != NULL)
+            *trans_alpha = NULL;
+      }
+
+      if (num_trans != NULL)
+      {
+         *num_trans = info_ptr->num_trans;
+         retval |= PNG_INFO_tRNS;
+      }
+   }
+
+   return (retval);
+}
+#endif
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+int PNGAPI
+png_get_unknown_chunks(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_unknown_chunkpp unknowns)
+{
+   if (png_ptr != NULL && info_ptr != NULL && unknowns != NULL)
+   {
+      *unknowns = info_ptr->unknown_chunks;
+      return info_ptr->unknown_chunks_num;
+   }
+
+   return (0);
+}
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+png_byte PNGAPI
+png_get_rgb_to_gray_status (png_const_structrp png_ptr)
+{
+   return (png_byte)(png_ptr ? png_ptr->rgb_to_gray_status : 0);
+}
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+png_voidp PNGAPI
+png_get_user_chunk_ptr(png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_chunk_ptr : NULL);
+}
+#endif
+
+size_t PNGAPI
+png_get_compression_buffer_size(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return 0;
+
+#ifdef PNG_WRITE_SUPPORTED
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+#endif
+   {
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+      return png_ptr->IDAT_read_size;
+#else
+      return PNG_IDAT_READ_SIZE;
+#endif
+   }
+
+#ifdef PNG_WRITE_SUPPORTED
+   else
+      return png_ptr->zbuffer_size;
+#endif
+}
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+/* These functions were added to libpng 1.2.6 and were enabled
+ * by default in libpng-1.4.0 */
+png_uint_32 PNGAPI
+png_get_user_width_max (png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_width_max : 0);
+}
+
+png_uint_32 PNGAPI
+png_get_user_height_max (png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_height_max : 0);
+}
+
+/* This function was added to libpng 1.4.0 */
+png_uint_32 PNGAPI
+png_get_chunk_cache_max (png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_chunk_cache_max : 0);
+}
+
+/* This function was added to libpng 1.4.1 */
+png_alloc_size_t PNGAPI
+png_get_chunk_malloc_max (png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_chunk_malloc_max : 0);
+}
+#endif /* SET_USER_LIMITS */
+
+/* These functions were added to libpng 1.4.0 */
+#ifdef PNG_IO_STATE_SUPPORTED
+png_uint_32 PNGAPI
+png_get_io_state (png_const_structrp png_ptr)
+{
+   return png_ptr->io_state;
+}
+
+png_uint_32 PNGAPI
+png_get_io_chunk_type (png_const_structrp png_ptr)
+{
+   return png_ptr->chunk_name;
+}
+#endif /* IO_STATE */
+
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+int PNGAPI
+png_get_palette_max(png_const_structp png_ptr, png_const_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return png_ptr->num_palette_max;
+
+   return (-1);
+}
+#  endif
+#endif
+
+#endif /* READ || WRITE */
diff --git a/extern/libpng/pnginfo.h b/extern/libpng/pnginfo.h
new file mode 100644
index 0000000000..1f98dedc42
--- /dev/null
+++ b/extern/libpng/pnginfo.h
@@ -0,0 +1,267 @@
+
+/* pnginfo.h - header file for PNG reference library
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2013,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+ /* png_info is a structure that holds the information in a PNG file so
+ * that the application can find out the characteristics of the image.
+ * If you are reading the file, this structure will tell you what is
+ * in the PNG file.  If you are writing the file, fill in the information
+ * you want to put into the PNG file, using png_set_*() functions, then
+ * call png_write_info().
+ *
+ * The names chosen should be very close to the PNG specification, so
+ * consult that document for information about the meaning of each field.
+ *
+ * With libpng < 0.95, it was only possible to directly set and read the
+ * the values in the png_info_struct, which meant that the contents and
+ * order of the values had to remain fixed.  With libpng 0.95 and later,
+ * however, there are now functions that abstract the contents of
+ * png_info_struct from the application, so this makes it easier to use
+ * libpng with dynamic libraries, and even makes it possible to use
+ * libraries that don't have all of the libpng ancillary chunk-handing
+ * functionality.  In libpng-1.5.0 this was moved into a separate private
+ * file that is not visible to applications.
+ *
+ * The following members may have allocated storage attached that should be
+ * cleaned up before the structure is discarded: palette, trans, text,
+ * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
+ * splt_palettes, scal_unit, row_pointers, and unknowns.   By default, these
+ * are automatically freed when the info structure is deallocated, if they were
+ * allocated internally by libpng.  This behavior can be changed by means
+ * of the png_data_freer() function.
+ *
+ * More allocation details: all the chunk-reading functions that
+ * change these members go through the corresponding png_set_*
+ * functions.  A function to clear these members is available: see
+ * png_free_data().  The png_set_* functions do not depend on being
+ * able to point info structure members to any of the storage they are
+ * passed (they make their own copies), EXCEPT that the png_set_text
+ * functions use the same storage passed to them in the text_ptr or
+ * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
+ * functions do not make their own copies.
+ */
+#ifndef PNGINFO_H
+#define PNGINFO_H
+
+struct png_info_def
+{
+   /* The following are necessary for every PNG file */
+   png_uint_32 width;       /* width of image in pixels (from IHDR) */
+   png_uint_32 height;      /* height of image in pixels (from IHDR) */
+   png_uint_32 valid;       /* valid chunk data (see PNG_INFO_ below) */
+   size_t rowbytes;         /* bytes needed to hold an untransformed row */
+   png_colorp palette;      /* array of color values (valid & PNG_INFO_PLTE) */
+   png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
+   png_uint_16 num_trans;   /* number of transparent palette color (tRNS) */
+   png_byte bit_depth;      /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
+   png_byte color_type;     /* see PNG_COLOR_TYPE_ below (from IHDR) */
+   /* The following three should have been named *_method not *_type */
+   png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
+   png_byte filter_type;    /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
+   png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
+
+   /* The following are set by png_set_IHDR, called from the application on
+    * write, but the are never actually used by the write code.
+    */
+   png_byte channels;       /* number of data channels per pixel (1, 2, 3, 4) */
+   png_byte pixel_depth;    /* number of bits per pixel */
+   png_byte spare_byte;     /* to align the data, and for future use */
+
+#ifdef PNG_READ_SUPPORTED
+   /* This is never set during write */
+   png_byte signature[8];   /* magic bytes read by libpng from start of file */
+#endif
+
+   /* The rest of the data is optional.  If you are reading, check the
+    * valid field to see if the information in these are valid.  If you
+    * are writing, set the valid field to those chunks you want written,
+    * and initialize the appropriate fields below.
+    */
+
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+   /* png_colorspace only contains 'flags' if neither GAMMA or COLORSPACE are
+    * defined.  When COLORSPACE is switched on all the colorspace-defining
+    * chunks should be enabled, when GAMMA is switched on all the gamma-defining
+    * chunks should be enabled.  If this is not done it becomes possible to read
+    * inconsistent PNG files and assign a probably incorrect interpretation to
+    * the information.  (In other words, by carefully choosing which chunks to
+    * recognize the system configuration can select an interpretation for PNG
+    * files containing ambiguous data and this will result in inconsistent
+    * behavior between different libpng builds!)
+    */
+   png_colorspace colorspace;
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+   /* iCCP chunk data. */
+   png_charp iccp_name;     /* profile name */
+   png_bytep iccp_profile;  /* International Color Consortium profile data */
+   png_uint_32 iccp_proflen;  /* ICC profile data length */
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+   /* The tEXt, and zTXt chunks contain human-readable textual data in
+    * uncompressed, compressed, and optionally compressed forms, respectively.
+    * The data in "text" is an array of pointers to uncompressed,
+    * null-terminated C strings. Each chunk has a keyword that describes the
+    * textual data contained in that chunk.  Keywords are not required to be
+    * unique, and the text string may be empty.  Any number of text chunks may
+    * be in an image.
+    */
+   int num_text; /* number of comments read or comments to write */
+   int max_text; /* current size of text array */
+   png_textp text; /* array of comments read or comments to write */
+#endif /* TEXT */
+
+#ifdef PNG_tIME_SUPPORTED
+   /* The tIME chunk holds the last time the displayed image data was
+    * modified.  See the png_time struct for the contents of this struct.
+    */
+   png_time mod_time;
+#endif
+
+#ifdef PNG_sBIT_SUPPORTED
+   /* The sBIT chunk specifies the number of significant high-order bits
+    * in the pixel data.  Values are in the range [1, bit_depth], and are
+    * only specified for the channels in the pixel data.  The contents of
+    * the low-order bits is not specified.  Data is valid if
+    * (valid & PNG_INFO_sBIT) is non-zero.
+    */
+   png_color_8 sig_bit; /* significant bits in color channels */
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
+defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* The tRNS chunk supplies transparency data for paletted images and
+    * other image types that don't need a full alpha channel.  There are
+    * "num_trans" transparency values for a paletted image, stored in the
+    * same order as the palette colors, starting from index 0.  Values
+    * for the data are in the range [0, 255], ranging from fully transparent
+    * to fully opaque, respectively.  For non-paletted images, there is a
+    * single color specified that should be treated as fully transparent.
+    * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
+    */
+   png_bytep trans_alpha;    /* alpha values for paletted image */
+   png_color_16 trans_color; /* transparent color for non-palette image */
+#endif
+
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* The bKGD chunk gives the suggested image background color if the
+    * display program does not have its own background color and the image
+    * is needs to composited onto a background before display.  The colors
+    * in "background" are normally in the same color space/depth as the
+    * pixel data.  Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
+    */
+   png_color_16 background;
+#endif
+
+#ifdef PNG_oFFs_SUPPORTED
+   /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
+    * and downwards from the top-left corner of the display, page, or other
+    * application-specific co-ordinate space.  See the PNG_OFFSET_ defines
+    * below for the unit types.  Valid if (valid & PNG_INFO_oFFs) non-zero.
+    */
+   png_int_32 x_offset; /* x offset on page */
+   png_int_32 y_offset; /* y offset on page */
+   png_byte offset_unit_type; /* offset units type */
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+   /* The pHYs chunk gives the physical pixel density of the image for
+    * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
+    * defines below).  Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
+    */
+   png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
+   png_uint_32 y_pixels_per_unit; /* vertical pixel density */
+   png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
+#endif
+
+#ifdef PNG_eXIf_SUPPORTED
+   int num_exif;  /* Added at libpng-1.6.31 */
+   png_bytep exif;
+# ifdef PNG_READ_eXIf_SUPPORTED
+   png_bytep eXIf_buf;  /* Added at libpng-1.6.32 */
+# endif
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+   /* The hIST chunk contains the relative frequency or importance of the
+    * various palette entries, so that a viewer can intelligently select a
+    * reduced-color palette, if required.  Data is an array of "num_palette"
+    * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
+    * is non-zero.
+    */
+   png_uint_16p hist;
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+   /* The pCAL chunk describes a transformation between the stored pixel
+    * values and original physical data values used to create the image.
+    * The integer range [0, 2^bit_depth - 1] maps to the floating-point
+    * range given by [pcal_X0, pcal_X1], and are further transformed by a
+    * (possibly non-linear) transformation function given by "pcal_type"
+    * and "pcal_params" into "pcal_units".  Please see the PNG_EQUATION_
+    * defines below, and the PNG-Group's PNG extensions document for a
+    * complete description of the transformations and how they should be
+    * implemented, and for a description of the ASCII parameter strings.
+    * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
+    */
+   png_charp pcal_purpose;  /* pCAL chunk description string */
+   png_int_32 pcal_X0;      /* minimum value */
+   png_int_32 pcal_X1;      /* maximum value */
+   png_charp pcal_units;    /* Latin-1 string giving physical units */
+   png_charpp pcal_params;  /* ASCII strings containing parameter values */
+   png_byte pcal_type;      /* equation type (see PNG_EQUATION_ below) */
+   png_byte pcal_nparams;   /* number of parameters given in pcal_params */
+#endif
+
+/* New members added in libpng-1.0.6 */
+   png_uint_32 free_me;     /* flags items libpng is responsible for freeing */
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+   /* Storage for unknown chunks that the library doesn't recognize. */
+   png_unknown_chunkp unknown_chunks;
+
+   /* The type of this field is limited by the type of
+    * png_struct::user_chunk_cache_max, else overflow can occur.
+    */
+   int                unknown_chunks_num;
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+   /* Data on sPLT chunks (there may be more than one). */
+   png_sPLT_tp splt_palettes;
+   int         splt_palettes_num; /* Match type returned by png_get API */
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+   /* The sCAL chunk describes the actual physical dimensions of the
+    * subject matter of the graphic.  The chunk contains a unit specification
+    * a byte value, and two ASCII strings representing floating-point
+    * values.  The values are width and height corresponding to one pixel
+    * in the image.  Data values are valid if (valid & PNG_INFO_sCAL) is
+    * non-zero.
+    */
+   png_byte scal_unit;         /* unit of physical scale */
+   png_charp scal_s_width;     /* string containing height */
+   png_charp scal_s_height;    /* string containing width */
+#endif
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+   /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS)
+      non-zero */
+   /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
+   png_bytepp row_pointers;        /* the image bits */
+#endif
+
+};
+#endif /* PNGINFO_H */
diff --git a/extern/libpng/pngmem.c b/extern/libpng/pngmem.c
new file mode 100644
index 0000000000..09ed9c1c99
--- /dev/null
+++ b/extern/libpng/pngmem.c
@@ -0,0 +1,284 @@
+
+/* pngmem.c - stub functions for memory allocation
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2014,2016 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all memory allocation.  Users who
+ * need special memory handling are expected to supply replacement
+ * functions for png_malloc() and png_free(), and to use
+ * png_create_read_struct_2() and png_create_write_struct_2() to
+ * identify the replacement functions.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Free a png_struct */
+void /* PRIVATE */
+png_destroy_png_struct(png_structrp png_ptr)
+{
+   if (png_ptr != NULL)
+   {
+      /* png_free might call png_error and may certainly call
+       * png_get_mem_ptr, so fake a temporary png_struct to support this.
+       */
+      png_struct dummy_struct = *png_ptr;
+      memset(png_ptr, 0, (sizeof *png_ptr));
+      png_free(&dummy_struct, png_ptr);
+
+#     ifdef PNG_SETJMP_SUPPORTED
+         /* We may have a jmp_buf left to deallocate. */
+         png_free_jmpbuf(&dummy_struct);
+#     endif
+   }
+}
+
+/* Allocate memory.  For reasonable files, size should never exceed
+ * 64K.  However, zlib may allocate more than 64K if you don't tell
+ * it not to.  See zconf.h and png.h for more information.  zlib does
+ * need to allocate exactly 64K, so whatever you call here must
+ * have the ability to do that.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_calloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+{
+   png_voidp ret;
+
+   ret = png_malloc(png_ptr, size);
+
+   if (ret != NULL)
+      memset(ret, 0, size);
+
+   return ret;
+}
+
+/* png_malloc_base, an internal function added at libpng 1.6.0, does the work of
+ * allocating memory, taking into account limits and PNG_USER_MEM_SUPPORTED.
+ * Checking and error handling must happen outside this routine; it returns NULL
+ * if the allocation cannot be done (for any reason.)
+ */
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size),
+    PNG_ALLOCATED)
+{
+   /* Moved to png_malloc_base from png_malloc_default in 1.6.0; the DOS
+    * allocators have also been removed in 1.6.0, so any 16-bit system now has
+    * to implement a user memory handler.  This checks to be sure it isn't
+    * called with big numbers.
+    */
+#ifndef PNG_USER_MEM_SUPPORTED
+   PNG_UNUSED(png_ptr)
+#endif
+
+   /* Some compilers complain that this is always true.  However, it
+    * can be false when integer overflow happens.
+    */
+   if (size > 0 && size <= PNG_SIZE_MAX
+#     ifdef PNG_MAX_MALLOC_64K
+         && size <= 65536U
+#     endif
+      )
+   {
+#ifdef PNG_USER_MEM_SUPPORTED
+      if (png_ptr != NULL && png_ptr->malloc_fn != NULL)
+         return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size);
+
+      else
+#endif
+         return malloc((size_t)size); /* checked for truncation above */
+   }
+
+   else
+      return NULL;
+}
+
+#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
+   defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
+/* This is really here only to work round a spurious warning in GCC 4.6 and 4.7
+ * that arises because of the checks in png_realloc_array that are repeated in
+ * png_malloc_array.
+ */
+static png_voidp
+png_malloc_array_checked(png_const_structrp png_ptr, int nelements,
+    size_t element_size)
+{
+   png_alloc_size_t req = (png_alloc_size_t)nelements; /* known to be > 0 */
+
+   if (req <= PNG_SIZE_MAX/element_size)
+      return png_malloc_base(png_ptr, req * element_size);
+
+   /* The failure case when the request is too large */
+   return NULL;
+}
+
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_malloc_array,(png_const_structrp png_ptr, int nelements,
+    size_t element_size),PNG_ALLOCATED)
+{
+   if (nelements <= 0 || element_size == 0)
+      png_error(png_ptr, "internal error: array alloc");
+
+   return png_malloc_array_checked(png_ptr, nelements, element_size);
+}
+
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array,
+    int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED)
+{
+   /* These are internal errors: */
+   if (add_elements <= 0 || element_size == 0 || old_elements < 0 ||
+      (old_array == NULL && old_elements > 0))
+      png_error(png_ptr, "internal error: array realloc");
+
+   /* Check for overflow on the elements count (so the caller does not have to
+    * check.)
+    */
+   if (add_elements <= INT_MAX - old_elements)
+   {
+      png_voidp new_array = png_malloc_array_checked(png_ptr,
+          old_elements+add_elements, element_size);
+
+      if (new_array != NULL)
+      {
+         /* Because png_malloc_array worked the size calculations below cannot
+          * overflow.
+          */
+         if (old_elements > 0)
+            memcpy(new_array, old_array, element_size*(unsigned)old_elements);
+
+         memset((char*)new_array + element_size*(unsigned)old_elements, 0,
+             element_size*(unsigned)add_elements);
+
+         return new_array;
+      }
+   }
+
+   return NULL; /* error */
+}
+#endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */
+
+/* Various functions that have different error handling are derived from this.
+ * png_malloc always exists, but if PNG_USER_MEM_SUPPORTED is defined a separate
+ * function png_malloc_default is also provided.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+{
+   png_voidp ret;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   ret = png_malloc_base(png_ptr, size);
+
+   if (ret == NULL)
+       png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */
+
+   return ret;
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),
+    PNG_ALLOCATED PNG_DEPRECATED)
+{
+   png_voidp ret;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   /* Passing 'NULL' here bypasses the application provided memory handler. */
+   ret = png_malloc_base(NULL/*use malloc*/, size);
+
+   if (ret == NULL)
+      png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */
+
+   return ret;
+}
+#endif /* USER_MEM */
+
+/* This function was added at libpng version 1.2.3.  The png_malloc_warn()
+ * function will issue a png_warning and return NULL instead of issuing a
+ * png_error, if it fails to allocate the requested memory.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_warn,(png_const_structrp png_ptr, png_alloc_size_t size),
+    PNG_ALLOCATED)
+{
+   if (png_ptr != NULL)
+   {
+      png_voidp ret = png_malloc_base(png_ptr, size);
+
+      if (ret != NULL)
+         return ret;
+
+      png_warning(png_ptr, "Out of memory");
+   }
+
+   return NULL;
+}
+
+/* Free a pointer allocated by png_malloc().  If ptr is NULL, return
+ * without taking any action.
+ */
+void PNGAPI
+png_free(png_const_structrp png_ptr, png_voidp ptr)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if (png_ptr->free_fn != NULL)
+      png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr);
+
+   else
+      png_free_default(png_ptr, ptr);
+}
+
+PNG_FUNCTION(void,PNGAPI
+png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+#endif /* USER_MEM */
+
+   free(ptr);
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* This function is called when the application wants to use another method
+ * of allocating and freeing memory.
+ */
+void PNGAPI
+png_set_mem_fn(png_structrp png_ptr, png_voidp mem_ptr, png_malloc_ptr
+  malloc_fn, png_free_ptr free_fn)
+{
+   if (png_ptr != NULL)
+   {
+      png_ptr->mem_ptr = mem_ptr;
+      png_ptr->malloc_fn = malloc_fn;
+      png_ptr->free_fn = free_fn;
+   }
+}
+
+/* This function returns a pointer to the mem_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_mem_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return NULL;
+
+   return png_ptr->mem_ptr;
+}
+#endif /* USER_MEM */
+#endif /* READ || WRITE */
diff --git a/extern/libpng/pngnow.png b/extern/libpng/pngnow.png
new file mode 100644
index 0000000000000000000000000000000000000000..82793ebddb7863266a66ffc6ab2c01ca32100808
GIT binary patch
literal 2069
zcmWkudpuN&7T#y<o7ZOO?uNrAM`M(Bqr(m{w;MC#)h4E)!`WVA8`6x?7}PYRX;947
zYi{S{OgK0lO7ci3y*zsHQ=-nPq!KFhKE-q<-MN3P^{sFHv3}ogt?#$?MT7@gnAw>D
z0ALXk%;6bOV2GtAMuxod+KXid08{<L`~jeOzqvl?9|rzS7B46OXdFad8i-SJFfR-M
z<O~2PPyxVaL#yBg0A#NQfayd4@ckJ8Y%;ayB3S@HNs7SvT>XL`q<{m10|OLLYbYp~
zqD01zCx~<rUrv(wDk5D$q|5jM66ZCL!U?@lJK%v40urR?F^^gO;DEkd3z<P`DT;f*
zbW2DU03*(HI>Qa;aTH3$83tYNL5@^&dW%qu3E?~lv;*N57-E2|bs(K#(iIEOmeFx%
zkcfvMOG`)&LHQ673#pIPl0s5bu0h@0>CO<}7a`Ws2_Xc#K~M$^F+q|Eqco5dLWna2
z#X^t(LKq<CfuKw}ClE(yFyaW(-Bw|~ESLu3p*T$Y7F)*w7lEWeq&if~k4?s73B-|(
z*dauG8XiqR6cA-%WR8LmN>oD8nRJmzN=KPsmsFupvRG!&XgFV8A;Y6t95Zm1LFa^q
z^92erLk2B|aULIYLrE_dC!DV+A~6Qa3B~AUAmL0W(=n6@Y2+%tkPyj9RsagyA*csN
zrps7?xTc~3G=mlSYRm(ZDb=D31>#001TxH*!;$k@LY&S-QNy%At*T6qc|mvuj(MT{
zShXyF6!Ad#Eru11piDK&6sbyVIXSpO33CD<Rv>}%6q-XYOk*K|bUdDgx`AW{hwjYa
zM<-xjEZA^`|H~$2a<yJa!izz~5#h&^EZ_Br9ZCp9Bn@UQwo=%^Fa^ZSKoJdw93i?R
zsHMS*90*wis%Wt02+Z<@dL8LF4eoNLql-X=974??RnY<15)?@bMCpna%>>8bLQKZ}
zLB^Jd#VHvwfGx?~A>ERiCUg3J?OJcAAZbdf6Hk&Nk_fY$mS?2o%GPH}1d{E{WQll1
z=-8g42GdW4aQykf``V&Q6W}O#EGzZC`E*NWZcMk35*qfRc}Z6Nnc{k=W$S9olPI;+
z@nk_TpA-koOx36tuc^5+8y2dJKCX$4z2CENV(>!in*_$fq1N2jW1W6k7j=WW!K2we
zQx6hfTZ3TdyW^y&(Mek}jvhFo%!~{*FP%!sE17a%?j{}9boS=;RS0g0Vl+OX*4!KG
zS9cV3_T@Rcztag#Ba8Akz?VEN{KY|&-cj^8X4hI9rOS7jb^I*rs9{W6y2#E2G^qzi
zdmWmqMl3bFs8=?8X$*f<{;;}lLq<aErk&T0<vw!gcs_PHFT^CBy}c_N_r3dVI6}4g
z^`o@-<+%=%TyDgFDO@$rrLyk}mG#4Uk&aDuZ>--wF|=g=DWXjt<5enf565lt)AmHV
zIxOb73llA}$8Ct~8-~_=j#_ZB`OnsJr4>ai);+T_!|ZPhrkXB?{B)};+#9l2+7C4G
z(7Hc=^#UXHmZ|>h%+um(yvmbWw|yz{+FO@id!cP~py}<7RoWpJ*Fa-`$lS+tJjBR&
z6tlD4Ti8JxCZ<oj)kn9)bof1rv#;FCx_{x_in-y^iXBI|-s0CUv$^L#cmH?@ZR{bd
zZcC*@8`~R~ZqInDE4TUU-c6h0`1Jdq-rru?yt$pazl-MSV%}d`@-e2haCu#{-pB9Z
zFgh~tgcZLid*3@_-=KRCek#Q_C;Q_`peOE&m%00*n`~Ql4DV)LA0b%6K&Z}MO{!H7
zrq0=w9+^+9lf+9J;#VnyYbA3P-ebu9zoVBc_t}QsEu@+o<yi+p$JXpcu9-X=YBycV
zov4eT?b{}JUfuf!UD1Do+vUA5cu|lHMZYe7ZDjoTUmX`d-Cmfhx;k6hY5weN_0<a(
z1%j<BimGtf_@4>9NMtT44qLLkP~+BFVn!|dbm^=AtK$C64)M~7nwq6^V!syIo2Oxw
z>Q`G3RCIQRk}|{IuYEXq#p2PEEha{j+{?DX0X|%93;f$J-{g|;y0D)gO{G>+cUcD`
z4y@ax<21CZK45QAznB)#Ufr}OXGc|jX9Ltdv+b8XbyW6-6`@zUuVY!hSGtpO`!`Qz
z&NQEk%buN|_~W2YVMOhus;$a%yh2m*KG^m|>9yn4nuBHYyEpCJ)0$=<bSQ^;97(x3
zqVa4$=elgzb>kK9Wtr0td+%|?D^-C{{MH<3%xF3Nr{}sKhiFd5L0;yj%{mN`D2E@j
zb9elGv{mRmpa=e4(SIT%(x!E1a$=RXWcVrny?jLXA=RCjub+PYvh*imzV73lzO2;z
z^IhX}vi&XOSKIaiO6bz9{*4VIPX4pcSiyJsOr)&7MIV0tt;fiC&DW%|Q{u`km5!dp
z!Uvmke~-D&46c>G#Z1ofQ!2y69!2#V?{T-pgjb1Z<)$Z0{jJ!Cd*WSVOiYG2O~X$e
zkOZV!x9`)jqV>P+UU{SXLBcfJe~UZ${fApm5?rT^HZwk-)*@r4(symdMMs05ch4L&
zKD%kQ5%->$aqgk4nHpEI84+blJ(2ds3O8Z;4>JTe4@PSyKg=thMLwxcsc|nVEJ)aH
z*B04qWpUia=q@`HDRXoAnzt<~x%EzDW7^4`nuh7CO5MicxId`hJsvyinB5bmk2>6A
rInt*5>ynshr7qiTo&3Aj@9hWbNS~fK{3iQ`;bQ_J+;C1~K%(-0k;znQ

literal 0
HcmV?d00001

diff --git a/extern/libpng/pngpread.c b/extern/libpng/pngpread.c
new file mode 100644
index 0000000000..e283627b77
--- /dev/null
+++ b/extern/libpng/pngpread.c
@@ -0,0 +1,1096 @@
+
+/* pngpread.c - read a png file in push mode
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+
+/* Push model modes */
+#define PNG_READ_SIG_MODE   0
+#define PNG_READ_CHUNK_MODE 1
+#define PNG_READ_IDAT_MODE  2
+#define PNG_READ_tEXt_MODE  4
+#define PNG_READ_zTXt_MODE  5
+#define PNG_READ_DONE_MODE  6
+#define PNG_READ_iTXt_MODE  7
+#define PNG_ERROR_MODE      8
+
+#define PNG_PUSH_SAVE_BUFFER_IF_FULL \
+if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
+   { png_push_save_buffer(png_ptr); return; }
+#define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
+if (png_ptr->buffer_size < N) \
+   { png_push_save_buffer(png_ptr); return; }
+
+void PNGAPI
+png_process_data(png_structrp png_ptr, png_inforp info_ptr,
+    png_bytep buffer, size_t buffer_size)
+{
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_push_restore_buffer(png_ptr, buffer, buffer_size);
+
+   while (png_ptr->buffer_size)
+   {
+      png_process_some_data(png_ptr, info_ptr);
+   }
+}
+
+size_t PNGAPI
+png_process_data_pause(png_structrp png_ptr, int save)
+{
+   if (png_ptr != NULL)
+   {
+      /* It's easiest for the caller if we do the save; then the caller doesn't
+       * have to supply the same data again:
+       */
+      if (save != 0)
+         png_push_save_buffer(png_ptr);
+      else
+      {
+         /* This includes any pending saved bytes: */
+         size_t remaining = png_ptr->buffer_size;
+         png_ptr->buffer_size = 0;
+
+         /* So subtract the saved buffer size, unless all the data
+          * is actually 'saved', in which case we just return 0
+          */
+         if (png_ptr->save_buffer_size < remaining)
+            return remaining - png_ptr->save_buffer_size;
+      }
+   }
+
+   return 0;
+}
+
+png_uint_32 PNGAPI
+png_process_data_skip(png_structrp png_ptr)
+{
+/* TODO: Deprecate and remove this API.
+ * Somewhere the implementation of this seems to have been lost,
+ * or abandoned.  It was only to support some internal back-door access
+ * to png_struct) in libpng-1.4.x.
+ */
+   png_app_warning(png_ptr,
+"png_process_data_skip is not implemented in any current version of libpng");
+   return 0;
+}
+
+/* What we do with the incoming data depends on what we were previously
+ * doing before we ran out of data...
+ */
+void /* PRIVATE */
+png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
+{
+   if (png_ptr == NULL)
+      return;
+
+   switch (png_ptr->process_mode)
+   {
+      case PNG_READ_SIG_MODE:
+      {
+         png_push_read_sig(png_ptr, info_ptr);
+         break;
+      }
+
+      case PNG_READ_CHUNK_MODE:
+      {
+         png_push_read_chunk(png_ptr, info_ptr);
+         break;
+      }
+
+      case PNG_READ_IDAT_MODE:
+      {
+         png_push_read_IDAT(png_ptr);
+         break;
+      }
+
+      default:
+      {
+         png_ptr->buffer_size = 0;
+         break;
+      }
+   }
+}
+
+/* Read any remaining signature bytes from the stream and compare them with
+ * the correct PNG signature.  It is possible that this routine is called
+ * with bytes already read from the signature, either because they have been
+ * checked by the calling application, or because of multiple calls to this
+ * routine.
+ */
+void /* PRIVATE */
+png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
+{
+   size_t num_checked = png_ptr->sig_bytes; /* SAFE, does not exceed 8 */
+   size_t num_to_check = 8 - num_checked;
+
+   if (png_ptr->buffer_size < num_to_check)
+   {
+      num_to_check = png_ptr->buffer_size;
+   }
+
+   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
+       num_to_check);
+   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
+
+   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
+   {
+      if (num_checked < 4 &&
+          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
+         png_error(png_ptr, "Not a PNG file");
+
+      else
+         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+   }
+   else
+   {
+      if (png_ptr->sig_bytes >= 8)
+      {
+         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+      }
+   }
+}
+
+void /* PRIVATE */
+png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
+{
+   png_uint_32 chunk_name;
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   int keep; /* unknown handling method */
+#endif
+
+   /* First we make sure we have enough data for the 4-byte chunk name
+    * and the 4-byte chunk length before proceeding with decoding the
+    * chunk data.  To fully decode each of these chunks, we also make
+    * sure we have enough data in the buffer for the 4-byte CRC at the
+    * end of every chunk (except IDAT, which is handled separately).
+    */
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+   {
+      png_byte chunk_length[4];
+      png_byte chunk_tag[4];
+
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+      png_push_fill_buffer(png_ptr, chunk_length, 4);
+      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
+      png_reset_crc(png_ptr);
+      png_crc_read(png_ptr, chunk_tag, 4);
+      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
+      png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+      png_check_chunk_length(png_ptr, png_ptr->push_length);
+      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+   }
+
+   chunk_name = png_ptr->chunk_name;
+
+   if (chunk_name == png_IDAT)
+   {
+      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+
+      /* If we reach an IDAT chunk, this means we have read all of the
+       * header chunks, and we can start reading the image (or if this
+       * is called after the image has been read - we have an error).
+       */
+      if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+         png_error(png_ptr, "Missing IHDR before IDAT");
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+          (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+         png_error(png_ptr, "Missing PLTE before IDAT");
+
+      png_ptr->process_mode = PNG_READ_IDAT_MODE;
+
+      if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+         if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
+            if (png_ptr->push_length == 0)
+               return;
+
+      png_ptr->mode |= PNG_HAVE_IDAT;
+
+      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+         png_benign_error(png_ptr, "Too many IDATs found");
+   }
+
+   if (chunk_name == png_IHDR)
+   {
+      if (png_ptr->push_length != 13)
+         png_error(png_ptr, "Invalid IHDR length");
+
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+   else if (chunk_name == png_IEND)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
+
+      png_ptr->process_mode = PNG_READ_DONE_MODE;
+      png_push_have_end(png_ptr, info_ptr);
+   }
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
+
+      if (chunk_name == png_PLTE)
+         png_ptr->mode |= PNG_HAVE_PLTE;
+   }
+#endif
+
+   else if (chunk_name == png_PLTE)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+   else if (chunk_name == png_IDAT)
+   {
+      png_ptr->idat_size = png_ptr->push_length;
+      png_ptr->process_mode = PNG_READ_IDAT_MODE;
+      png_push_have_info(png_ptr, info_ptr);
+      png_ptr->zstream.avail_out =
+          (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
+          png_ptr->iwidth) + 1;
+      png_ptr->zstream.next_out = png_ptr->row_buf;
+      return;
+   }
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+   else if (png_ptr->chunk_name == png_gAMA)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_sBIT_SUPPORTED
+   else if (png_ptr->chunk_name == png_sBIT)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_cHRM_SUPPORTED
+   else if (png_ptr->chunk_name == png_cHRM)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_sRGB_SUPPORTED
+   else if (chunk_name == png_sRGB)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_iCCP_SUPPORTED
+   else if (png_ptr->chunk_name == png_iCCP)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_sPLT_SUPPORTED
+   else if (chunk_name == png_sPLT)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_tRNS_SUPPORTED
+   else if (chunk_name == png_tRNS)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_bKGD_SUPPORTED
+   else if (chunk_name == png_bKGD)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_hIST_SUPPORTED
+   else if (chunk_name == png_hIST)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_pHYs_SUPPORTED
+   else if (chunk_name == png_pHYs)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_oFFs_SUPPORTED
+   else if (chunk_name == png_oFFs)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+   else if (chunk_name == png_pCAL)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_sCAL_SUPPORTED
+   else if (chunk_name == png_sCAL)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_tIME_SUPPORTED
+   else if (chunk_name == png_tIME)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_tEXt_SUPPORTED
+   else if (chunk_name == png_tEXt)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_zTXt_SUPPORTED
+   else if (chunk_name == png_zTXt)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_iTXt_SUPPORTED
+   else if (chunk_name == png_iTXt)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+
+   else
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
+          PNG_HANDLE_CHUNK_AS_DEFAULT);
+   }
+
+   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+}
+
+void PNGCBAPI
+png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, size_t length)
+{
+   png_bytep ptr;
+
+   if (png_ptr == NULL)
+      return;
+
+   ptr = buffer;
+   if (png_ptr->save_buffer_size != 0)
+   {
+      size_t save_size;
+
+      if (length < png_ptr->save_buffer_size)
+         save_size = length;
+
+      else
+         save_size = png_ptr->save_buffer_size;
+
+      memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
+      length -= save_size;
+      ptr += save_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->save_buffer_size -= save_size;
+      png_ptr->save_buffer_ptr += save_size;
+   }
+   if (length != 0 && png_ptr->current_buffer_size != 0)
+   {
+      size_t save_size;
+
+      if (length < png_ptr->current_buffer_size)
+         save_size = length;
+
+      else
+         save_size = png_ptr->current_buffer_size;
+
+      memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
+      png_ptr->buffer_size -= save_size;
+      png_ptr->current_buffer_size -= save_size;
+      png_ptr->current_buffer_ptr += save_size;
+   }
+}
+
+void /* PRIVATE */
+png_push_save_buffer(png_structrp png_ptr)
+{
+   if (png_ptr->save_buffer_size != 0)
+   {
+      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
+      {
+         size_t i, istop;
+         png_bytep sp;
+         png_bytep dp;
+
+         istop = png_ptr->save_buffer_size;
+         for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
+             i < istop; i++, sp++, dp++)
+         {
+            *dp = *sp;
+         }
+      }
+   }
+   if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
+       png_ptr->save_buffer_max)
+   {
+      size_t new_max;
+      png_bytep old_buffer;
+
+      if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
+          (png_ptr->current_buffer_size + 256))
+      {
+         png_error(png_ptr, "Potential overflow of save_buffer");
+      }
+
+      new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
+      old_buffer = png_ptr->save_buffer;
+      png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
+          (size_t)new_max);
+
+      if (png_ptr->save_buffer == NULL)
+      {
+         png_free(png_ptr, old_buffer);
+         png_error(png_ptr, "Insufficient memory for save_buffer");
+      }
+
+      if (old_buffer)
+         memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
+      else if (png_ptr->save_buffer_size)
+         png_error(png_ptr, "save_buffer error");
+      png_free(png_ptr, old_buffer);
+      png_ptr->save_buffer_max = new_max;
+   }
+   if (png_ptr->current_buffer_size)
+   {
+      memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
+         png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
+      png_ptr->save_buffer_size += png_ptr->current_buffer_size;
+      png_ptr->current_buffer_size = 0;
+   }
+   png_ptr->save_buffer_ptr = png_ptr->save_buffer;
+   png_ptr->buffer_size = 0;
+}
+
+void /* PRIVATE */
+png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
+    size_t buffer_length)
+{
+   png_ptr->current_buffer = buffer;
+   png_ptr->current_buffer_size = buffer_length;
+   png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
+   png_ptr->current_buffer_ptr = png_ptr->current_buffer;
+}
+
+void /* PRIVATE */
+png_push_read_IDAT(png_structrp png_ptr)
+{
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+   {
+      png_byte chunk_length[4];
+      png_byte chunk_tag[4];
+
+      /* TODO: this code can be commoned up with the same code in push_read */
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+      png_push_fill_buffer(png_ptr, chunk_length, 4);
+      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
+      png_reset_crc(png_ptr);
+      png_crc_read(png_ptr, chunk_tag, 4);
+      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
+      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+
+      if (png_ptr->chunk_name != png_IDAT)
+      {
+         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+
+         if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+            png_error(png_ptr, "Not enough compressed data");
+
+         return;
+      }
+
+      png_ptr->idat_size = png_ptr->push_length;
+   }
+
+   if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
+   {
+      size_t save_size = png_ptr->save_buffer_size;
+      png_uint_32 idat_size = png_ptr->idat_size;
+
+      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+       * are of different types and we don't know which variable has the fewest
+       * bits.  Carefully select the smaller and cast it to the type of the
+       * larger - this cannot overflow.  Do not cast in the following test - it
+       * will break on either 16-bit or 64-bit platforms.
+       */
+      if (idat_size < save_size)
+         save_size = (size_t)idat_size;
+
+      else
+         idat_size = (png_uint_32)save_size;
+
+      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+      png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+      png_ptr->idat_size -= idat_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->save_buffer_size -= save_size;
+      png_ptr->save_buffer_ptr += save_size;
+   }
+
+   if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
+   {
+      size_t save_size = png_ptr->current_buffer_size;
+      png_uint_32 idat_size = png_ptr->idat_size;
+
+      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+       * are of different types and we don't know which variable has the fewest
+       * bits.  Carefully select the smaller and cast it to the type of the
+       * larger - this cannot overflow.
+       */
+      if (idat_size < save_size)
+         save_size = (size_t)idat_size;
+
+      else
+         idat_size = (png_uint_32)save_size;
+
+      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+      png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+      png_ptr->idat_size -= idat_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->current_buffer_size -= save_size;
+      png_ptr->current_buffer_ptr += save_size;
+   }
+
+   if (png_ptr->idat_size == 0)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
+      png_crc_finish(png_ptr, 0);
+      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+      png_ptr->mode |= PNG_AFTER_IDAT;
+      png_ptr->zowner = 0;
+   }
+}
+
+void /* PRIVATE */
+png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
+    size_t buffer_length)
+{
+   /* The caller checks for a non-zero buffer length. */
+   if (!(buffer_length > 0) || buffer == NULL)
+      png_error(png_ptr, "No IDAT data (internal error)");
+
+   /* This routine must process all the data it has been given
+    * before returning, calling the row callback as required to
+    * handle the uncompressed results.
+    */
+   png_ptr->zstream.next_in = buffer;
+   /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
+   png_ptr->zstream.avail_in = (uInt)buffer_length;
+
+   /* Keep going until the decompressed data is all processed
+    * or the stream marked as finished.
+    */
+   while (png_ptr->zstream.avail_in > 0 &&
+      (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+   {
+      int ret;
+
+      /* We have data for zlib, but we must check that zlib
+       * has someplace to put the results.  It doesn't matter
+       * if we don't expect any results -- it may be the input
+       * data is just the LZ end code.
+       */
+      if (!(png_ptr->zstream.avail_out > 0))
+      {
+         /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
+         png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
+             png_ptr->iwidth) + 1);
+
+         png_ptr->zstream.next_out = png_ptr->row_buf;
+      }
+
+      /* Using Z_SYNC_FLUSH here means that an unterminated
+       * LZ stream (a stream with a missing end code) can still
+       * be handled, otherwise (Z_NO_FLUSH) a future zlib
+       * implementation might defer output and therefore
+       * change the current behavior (see comments in inflate.c
+       * for why this doesn't happen at present with zlib 1.2.5).
+       */
+      ret = PNG_INFLATE(png_ptr, Z_SYNC_FLUSH);
+
+      /* Check for any failure before proceeding. */
+      if (ret != Z_OK && ret != Z_STREAM_END)
+      {
+         /* Terminate the decompression. */
+         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+         png_ptr->zowner = 0;
+
+         /* This may be a truncated stream (missing or
+          * damaged end code).  Treat that as a warning.
+          */
+         if (png_ptr->row_number >= png_ptr->num_rows ||
+             png_ptr->pass > 6)
+            png_warning(png_ptr, "Truncated compressed data in IDAT");
+
+         else
+         {
+            if (ret == Z_DATA_ERROR)
+               png_benign_error(png_ptr, "IDAT: ADLER32 checksum mismatch");
+            else
+               png_error(png_ptr, "Decompression error in IDAT");
+         }
+
+         /* Skip the check on unprocessed input */
+         return;
+      }
+
+      /* Did inflate output any data? */
+      if (png_ptr->zstream.next_out != png_ptr->row_buf)
+      {
+         /* Is this unexpected data after the last row?
+          * If it is, artificially terminate the LZ output
+          * here.
+          */
+         if (png_ptr->row_number >= png_ptr->num_rows ||
+             png_ptr->pass > 6)
+         {
+            /* Extra data. */
+            png_warning(png_ptr, "Extra compressed data in IDAT");
+            png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+            png_ptr->zowner = 0;
+
+            /* Do no more processing; skip the unprocessed
+             * input check below.
+             */
+            return;
+         }
+
+         /* Do we have a complete row? */
+         if (png_ptr->zstream.avail_out == 0)
+            png_push_process_row(png_ptr);
+      }
+
+      /* And check for the end of the stream. */
+      if (ret == Z_STREAM_END)
+         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+   }
+
+   /* All the data should have been processed, if anything
+    * is left at this point we have bytes of IDAT data
+    * after the zlib end code.
+    */
+   if (png_ptr->zstream.avail_in > 0)
+      png_warning(png_ptr, "Extra compression data in IDAT");
+}
+
+void /* PRIVATE */
+png_push_process_row(png_structrp png_ptr)
+{
+   /* 1.5.6: row_info moved out of png_struct to a local here. */
+   png_row_info row_info;
+
+   row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
+   row_info.color_type = png_ptr->color_type;
+   row_info.bit_depth = png_ptr->bit_depth;
+   row_info.channels = png_ptr->channels;
+   row_info.pixel_depth = png_ptr->pixel_depth;
+   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+   if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
+   {
+      if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
+         png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
+            png_ptr->prev_row + 1, png_ptr->row_buf[0]);
+      else
+         png_error(png_ptr, "bad adaptive filter value");
+   }
+
+   /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
+    * 1.5.6, while the buffer really is this big in current versions of libpng
+    * it may not be in the future, so this was changed just to copy the
+    * interlaced row count:
+    */
+   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+   if (png_ptr->transformations != 0)
+      png_do_read_transformations(png_ptr, &row_info);
+#endif
+
+   /* The transformed pixel depth should match the depth now in row_info. */
+   if (png_ptr->transformed_pixel_depth == 0)
+   {
+      png_ptr->transformed_pixel_depth = row_info.pixel_depth;
+      if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
+         png_error(png_ptr, "progressive row overflow");
+   }
+
+   else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
+      png_error(png_ptr, "internal progressive row size calculation error");
+
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* Expand interlaced rows to full size */
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      if (png_ptr->pass < 6)
+         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
+             png_ptr->transformations);
+
+      switch (png_ptr->pass)
+      {
+         case 0:
+         {
+            int i;
+            for (i = 0; i < 8 && png_ptr->pass == 0; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
+            }
+
+            if (png_ptr->pass == 2) /* Pass 1 might be empty */
+            {
+               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            if (png_ptr->pass == 4 && png_ptr->height <= 4)
+            {
+               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            if (png_ptr->pass == 6 && png_ptr->height <= 4)
+            {
+                png_push_have_row(png_ptr, NULL);
+                png_read_push_finish_row(png_ptr);
+            }
+
+            break;
+         }
+
+         case 1:
+         {
+            int i;
+            for (i = 0; i < 8 && png_ptr->pass == 1; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 2) /* Skip top 4 generated rows */
+            {
+               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            break;
+         }
+
+         case 2:
+         {
+            int i;
+
+            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+            {
+               png_push_have_row(png_ptr, NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 4) /* Pass 3 might be empty */
+            {
+               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            break;
+         }
+
+         case 3:
+         {
+            int i;
+
+            for (i = 0; i < 4 && png_ptr->pass == 3; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 4) /* Skip top two generated rows */
+            {
+               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            break;
+         }
+
+         case 4:
+         {
+            int i;
+
+            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+            {
+               png_push_have_row(png_ptr, NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 6) /* Pass 5 might be empty */
+            {
+               png_push_have_row(png_ptr, NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            break;
+         }
+
+         case 5:
+         {
+            int i;
+
+            for (i = 0; i < 2 && png_ptr->pass == 5; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 6) /* Skip top generated row */
+            {
+               png_push_have_row(png_ptr, NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            break;
+         }
+
+         default:
+         case 6:
+         {
+            png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+            png_read_push_finish_row(png_ptr);
+
+            if (png_ptr->pass != 6)
+               break;
+
+            png_push_have_row(png_ptr, NULL);
+            png_read_push_finish_row(png_ptr);
+         }
+      }
+   }
+   else
+#endif
+   {
+      png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+      png_read_push_finish_row(png_ptr);
+   }
+}
+
+void /* PRIVATE */
+png_read_push_finish_row(png_structrp png_ptr)
+{
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
+
+   /* Height of interlace block.  This is not currently used - if you need
+    * it, uncomment it here and in png.h
+   static const png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+   */
+#endif
+
+   png_ptr->row_number++;
+   if (png_ptr->row_number < png_ptr->num_rows)
+      return;
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   if (png_ptr->interlaced != 0)
+   {
+      png_ptr->row_number = 0;
+      memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+      do
+      {
+         png_ptr->pass++;
+         if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
+             (png_ptr->pass == 3 && png_ptr->width < 3) ||
+             (png_ptr->pass == 5 && png_ptr->width < 2))
+            png_ptr->pass++;
+
+         if (png_ptr->pass > 7)
+            png_ptr->pass--;
+
+         if (png_ptr->pass >= 7)
+            break;
+
+         png_ptr->iwidth = (png_ptr->width +
+             png_pass_inc[png_ptr->pass] - 1 -
+             png_pass_start[png_ptr->pass]) /
+             png_pass_inc[png_ptr->pass];
+
+         if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+            break;
+
+         png_ptr->num_rows = (png_ptr->height +
+             png_pass_yinc[png_ptr->pass] - 1 -
+             png_pass_ystart[png_ptr->pass]) /
+             png_pass_yinc[png_ptr->pass];
+
+      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
+   }
+#endif /* READ_INTERLACING */
+}
+
+void /* PRIVATE */
+png_push_have_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+   if (png_ptr->info_fn != NULL)
+      (*(png_ptr->info_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+   if (png_ptr->end_fn != NULL)
+      (*(png_ptr->end_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_row(png_structrp png_ptr, png_bytep row)
+{
+   if (png_ptr->row_fn != NULL)
+      (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
+          (int)png_ptr->pass);
+}
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+void PNGAPI
+png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
+    png_const_bytep new_row)
+{
+   if (png_ptr == NULL)
+      return;
+
+   /* new_row is a flag here - if it is NULL then the app callback was called
+    * from an empty row (see the calls to png_struct::row_fn below), otherwise
+    * it must be png_ptr->row_buf+1
+    */
+   if (new_row != NULL)
+      png_combine_row(png_ptr, old_row, 1/*blocky display*/);
+}
+#endif /* READ_INTERLACING */
+
+void PNGAPI
+png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
+    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
+    png_progressive_end_ptr end_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->info_fn = info_fn;
+   png_ptr->row_fn = row_fn;
+   png_ptr->end_fn = end_fn;
+
+   png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
+}
+
+png_voidp PNGAPI
+png_get_progressive_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return (NULL);
+
+   return png_ptr->io_ptr;
+}
+#endif /* PROGRESSIVE_READ */
diff --git a/extern/libpng/pngpriv.h b/extern/libpng/pngpriv.h
new file mode 100644
index 0000000000..583c26f9bd
--- /dev/null
+++ b/extern/libpng/pngpriv.h
@@ -0,0 +1,2152 @@
+
+/* pngpriv.h - private declarations for use inside libpng
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* The symbols declared in this file (including the functions declared
+ * as extern) are PRIVATE.  They are not part of the libpng public
+ * interface, and are not recommended for use by regular applications.
+ * Some of them may become public in the future; others may stay private,
+ * change in an incompatible way, or even disappear.
+ * Although the libpng users are not forbidden to include this header,
+ * they should be well aware of the issues that may arise from doing so.
+ */
+
+#ifndef PNGPRIV_H
+#define PNGPRIV_H
+
+/* Feature Test Macros.  The following are defined here to ensure that correctly
+ * implemented libraries reveal the APIs libpng needs to build and hide those
+ * that are not needed and potentially damaging to the compilation.
+ *
+ * Feature Test Macros must be defined before any system header is included (see
+ * POSIX 1003.1 2.8.2 "POSIX Symbols."
+ *
+ * These macros only have an effect if the operating system supports either
+ * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
+ * Windows/Visual Studio) there is no effect; the OS specific tests below are
+ * still required (as of 2011-05-02.)
+ */
+#ifndef _POSIX_SOURCE
+# define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+/* Standard library headers not required by png.h: */
+#  include <stdlib.h>
+#  include <string.h>
+#endif
+
+#define PNGLIB_BUILD /*libpng is being built, not used*/
+
+/* If HAVE_CONFIG_H is defined during the build then the build system must
+ * provide an appropriate "config.h" file on the include path.  The header file
+ * must provide definitions as required below (search for "HAVE_CONFIG_H");
+ * see configure.ac for more details of the requirements.  The macro
+ * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on
+ * 'configure'; define this macro to prevent the configure build including the
+ * configure generated config.h.  Libpng is expected to compile without *any*
+ * special build system support on a reasonably ANSI-C compliant system.
+ */
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+
+   /* Pick up the definition of 'restrict' from config.h if it was read: */
+#  define PNG_RESTRICT restrict
+#endif
+
+/* To support symbol prefixing it is necessary to know *before* including png.h
+ * whether the fixed point (and maybe other) APIs are exported, because if they
+ * are not internal definitions may be required.  This is handled below just
+ * before png.h is included, but load the configuration now if it is available.
+ */
+#ifndef PNGLCONF_H
+#  include "pnglibconf.h"
+#endif
+
+/* Local renames may change non-exported API functions from png.h */
+#if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
+#  include "pngprefix.h"
+#endif
+
+#ifdef PNG_USER_CONFIG
+#  include "pngusr.h"
+   /* These should have been defined in pngusr.h */
+#  ifndef PNG_USER_PRIVATEBUILD
+#    define PNG_USER_PRIVATEBUILD "Custom libpng build"
+#  endif
+#  ifndef PNG_USER_DLLFNAME_POSTFIX
+#    define PNG_USER_DLLFNAME_POSTFIX "Cb"
+#  endif
+#endif
+
+/* Compile time options.
+ * =====================
+ * In a multi-arch build the compiler may compile the code several times for the
+ * same object module, producing different binaries for different architectures.
+ * When this happens configure-time setting of the target host options cannot be
+ * done and this interferes with the handling of the ARM NEON optimizations, and
+ * possibly other similar optimizations.  Put additional tests here; in general
+ * this is needed when the same option can be changed at both compile time and
+ * run time depending on the target OS (i.e. iOS vs Android.)
+ *
+ * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because
+ * this is not possible with certain compilers (Oracle SUN OS CC), as a result
+ * it is necessary to ensure that all extern functions that *might* be used
+ * regardless of $(CFLAGS) get declared in this file.  The test on __ARM_NEON__
+ * below is one example of this behavior because it is controlled by the
+ * presence or not of -mfpu=neon on the GCC command line, it is possible to do
+ * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely
+ * do this.
+ */
+#ifndef PNG_ARM_NEON_OPT
+   /* ARM NEON optimizations are being controlled by the compiler settings,
+    * typically the target FPU.  If the FPU has been set to NEON (-mfpu=neon
+    * with GCC) then the compiler will define __ARM_NEON__ and we can rely
+    * unconditionally on NEON instructions not crashing, otherwise we must
+    * disable use of NEON instructions.
+    *
+    * NOTE: at present these optimizations depend on 'ALIGNED_MEMORY', so they
+    * can only be turned on automatically if that is supported too.  If
+    * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail
+    * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
+    * off.
+    *
+    * Note that gcc-4.9 defines __ARM_NEON instead of the deprecated
+    * __ARM_NEON__, so we check both variants.
+    *
+    * To disable ARM_NEON optimizations entirely, and skip compiling the
+    * associated assembler code, pass --enable-arm-neon=no to configure
+    * or put -DPNG_ARM_NEON_OPT=0 in CPPFLAGS.
+    */
+#  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
+   defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+#     define PNG_ARM_NEON_OPT 2
+#  else
+#     define PNG_ARM_NEON_OPT 0
+#  endif
+#endif
+
+#if PNG_ARM_NEON_OPT > 0
+   /* NEON optimizations are to be at least considered by libpng, so enable the
+    * callbacks to do this.
+    */
+#  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
+
+   /* By default the 'intrinsics' code in arm/filter_neon_intrinsics.c is used
+    * if possible - if __ARM_NEON__ is set and the compiler version is not known
+    * to be broken.  This is controlled by PNG_ARM_NEON_IMPLEMENTATION which can
+    * be:
+    *
+    *    1  The intrinsics code (the default with __ARM_NEON__)
+    *    2  The hand coded assembler (the default without __ARM_NEON__)
+    *
+    * It is possible to set PNG_ARM_NEON_IMPLEMENTATION in CPPFLAGS, however
+    * this is *NOT* supported and may cease to work even after a minor revision
+    * to libpng.  It *is* valid to do this for testing purposes, e.g. speed
+    * testing or a new compiler, but the results should be communicated to the
+    * libpng implementation list for incorporation in the next minor release.
+    */
+#  ifndef PNG_ARM_NEON_IMPLEMENTATION
+#     if defined(__ARM_NEON__) || defined(__ARM_NEON)
+#        if defined(__clang__)
+            /* At present it is unknown by the libpng developers which versions
+             * of clang support the intrinsics, however some or perhaps all
+             * versions do not work with the assembler so this may be
+             * irrelevant, so just use the default (do nothing here.)
+             */
+#        elif defined(__GNUC__)
+            /* GCC 4.5.4 NEON support is known to be broken.  4.6.3 is known to
+             * work, so if this *is* GCC, or G++, look for a version >4.5
+             */
+#           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
+#              define PNG_ARM_NEON_IMPLEMENTATION 2
+#           endif /* no GNUC support */
+#        endif /* __GNUC__ */
+#     else /* !defined __ARM_NEON__ */
+         /* The 'intrinsics' code simply won't compile without this -mfpu=neon:
+          */
+#        if !defined(__aarch64__)
+            /* The assembler code currently does not work on ARM64 */
+#          define PNG_ARM_NEON_IMPLEMENTATION 2
+#        endif /* __aarch64__ */
+#     endif /* __ARM_NEON__ */
+#  endif /* !PNG_ARM_NEON_IMPLEMENTATION */
+
+#  ifndef PNG_ARM_NEON_IMPLEMENTATION
+      /* Use the intrinsics code by default. */
+#     define PNG_ARM_NEON_IMPLEMENTATION 1
+#  endif
+#endif /* PNG_ARM_NEON_OPT > 0 */
+
+#ifndef PNG_MIPS_MSA_OPT
+#  if defined(__mips_msa) && (__mips_isa_rev >= 5) && defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+#     define PNG_MIPS_MSA_OPT 2
+#  else
+#     define PNG_MIPS_MSA_OPT 0
+#  endif
+#endif
+
+#ifndef PNG_POWERPC_VSX_OPT
+#  if defined(__PPC64__) && defined(__ALTIVEC__) && defined(__VSX__)
+#     define PNG_POWERPC_VSX_OPT 2
+#  else
+#     define PNG_POWERPC_VSX_OPT 0
+#  endif
+#endif
+
+#ifndef PNG_INTEL_SSE_OPT
+#   ifdef PNG_INTEL_SSE
+      /* Only check for SSE if the build configuration has been modified to
+       * enable SSE optimizations.  This means that these optimizations will
+       * be off by default.  See contrib/intel for more details.
+       */
+#     if defined(__SSE4_1__) || defined(__AVX__) || defined(__SSSE3__) || \
+       defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
+       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
+#         define PNG_INTEL_SSE_OPT 1
+#      else
+#         define PNG_INTEL_SSE_OPT 0
+#      endif
+#   else
+#      define PNG_INTEL_SSE_OPT 0
+#   endif
+#endif
+
+#if PNG_INTEL_SSE_OPT > 0
+#   ifndef PNG_INTEL_SSE_IMPLEMENTATION
+#      if defined(__SSE4_1__) || defined(__AVX__)
+          /* We are not actually using AVX, but checking for AVX is the best
+             way we can detect SSE4.1 and SSSE3 on MSVC.
+          */
+#         define PNG_INTEL_SSE_IMPLEMENTATION 3
+#      elif defined(__SSSE3__)
+#         define PNG_INTEL_SSE_IMPLEMENTATION 2
+#      elif defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
+       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
+#         define PNG_INTEL_SSE_IMPLEMENTATION 1
+#      else
+#         define PNG_INTEL_SSE_IMPLEMENTATION 0
+#      endif
+#   endif
+
+#   if PNG_INTEL_SSE_IMPLEMENTATION > 0
+#      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_sse2
+#   endif
+#else
+#   define PNG_INTEL_SSE_IMPLEMENTATION 0
+#endif
+
+#if PNG_MIPS_MSA_OPT > 0
+#  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_msa
+#  ifndef PNG_MIPS_MSA_IMPLEMENTATION
+#     if defined(__mips_msa)
+#        if defined(__clang__)
+#        elif defined(__GNUC__)
+#           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
+#              define PNG_MIPS_MSA_IMPLEMENTATION 2
+#           endif /* no GNUC support */
+#        endif /* __GNUC__ */
+#     else /* !defined __mips_msa */
+#        define PNG_MIPS_MSA_IMPLEMENTATION 2
+#     endif /* __mips_msa */
+#  endif /* !PNG_MIPS_MSA_IMPLEMENTATION */
+
+#  ifndef PNG_MIPS_MSA_IMPLEMENTATION
+#     define PNG_MIPS_MSA_IMPLEMENTATION 1
+#  endif
+#endif /* PNG_MIPS_MSA_OPT > 0 */
+
+#if PNG_POWERPC_VSX_OPT > 0
+#  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_vsx
+#  define PNG_POWERPC_VSX_IMPLEMENTATION 1
+#endif
+
+
+/* Is this a build of a DLL where compilation of the object modules requires
+ * different preprocessor settings to those required for a simple library?  If
+ * so PNG_BUILD_DLL must be set.
+ *
+ * If libpng is used inside a DLL but that DLL does not export the libpng APIs
+ * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
+ * static library of libpng then link the DLL against that.
+ */
+#ifndef PNG_BUILD_DLL
+#  ifdef DLL_EXPORT
+      /* This is set by libtool when files are compiled for a DLL; libtool
+       * always compiles twice, even on systems where it isn't necessary.  Set
+       * PNG_BUILD_DLL in case it is necessary:
+       */
+#     define PNG_BUILD_DLL
+#  else
+#     ifdef _WINDLL
+         /* This is set by the Microsoft Visual Studio IDE in projects that
+          * build a DLL.  It can't easily be removed from those projects (it
+          * isn't visible in the Visual Studio UI) so it is a fairly reliable
+          * indication that PNG_IMPEXP needs to be set to the DLL export
+          * attributes.
+          */
+#        define PNG_BUILD_DLL
+#     else
+#        ifdef __DLL__
+            /* This is set by the Borland C system when compiling for a DLL
+             * (as above.)
+             */
+#           define PNG_BUILD_DLL
+#        else
+            /* Add additional compiler cases here. */
+#        endif
+#     endif
+#  endif
+#endif /* Setting PNG_BUILD_DLL if required */
+
+/* See pngconf.h for more details: the builder of the library may set this on
+ * the command line to the right thing for the specific compilation system or it
+ * may be automagically set above (at present we know of no system where it does
+ * need to be set on the command line.)
+ *
+ * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
+ * setting it to the "import" setting for a DLL build.
+ */
+#ifndef PNG_IMPEXP
+#  ifdef PNG_BUILD_DLL
+#     define PNG_IMPEXP PNG_DLL_EXPORT
+#  else
+      /* Not building a DLL, or the DLL doesn't require specific export
+       * definitions.
+       */
+#     define PNG_IMPEXP
+#  endif
+#endif
+
+/* No warnings for private or deprecated functions in the build: */
+#ifndef PNG_DEPRECATED
+#  define PNG_DEPRECATED
+#endif
+#ifndef PNG_PRIVATE
+#  define PNG_PRIVATE
+#endif
+
+/* Symbol preprocessing support.
+ *
+ * To enable listing global, but internal, symbols the following macros should
+ * always be used to declare an extern data or function object in this file.
+ */
+#ifndef PNG_INTERNAL_DATA
+#  define PNG_INTERNAL_DATA(type, name, array) PNG_LINKAGE_DATA type name array
+#endif
+
+#ifndef PNG_INTERNAL_FUNCTION
+#  define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
+      PNG_LINKAGE_FUNCTION PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
+#endif
+
+#ifndef PNG_INTERNAL_CALLBACK
+#  define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
+      PNG_LINKAGE_CALLBACK PNG_FUNCTION(type, (PNGCBAPI name), args,\
+         PNG_EMPTY attributes)
+#endif
+
+/* If floating or fixed point APIs are disabled they may still be compiled
+ * internally.  To handle this make sure they are declared as the appropriate
+ * internal extern function (otherwise the symbol prefixing stuff won't work and
+ * the functions will be used without definitions.)
+ *
+ * NOTE: although all the API functions are declared here they are not all
+ * actually built!  Because the declarations are still made it is necessary to
+ * fake out types that they depend on.
+ */
+#ifndef PNG_FP_EXPORT
+#  ifndef PNG_FLOATING_POINT_SUPPORTED
+#     define PNG_FP_EXPORT(ordinal, type, name, args)\
+         PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
+#     ifndef PNG_VERSION_INFO_ONLY
+         typedef struct png_incomplete png_double;
+         typedef png_double*           png_doublep;
+         typedef const png_double*     png_const_doublep;
+         typedef png_double**          png_doublepp;
+#     endif
+#  endif
+#endif
+#ifndef PNG_FIXED_EXPORT
+#  ifndef PNG_FIXED_POINT_SUPPORTED
+#     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
+         PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
+#  endif
+#endif
+
+#include "png.h"
+
+/* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
+#ifndef PNG_DLL_EXPORT
+#  define PNG_DLL_EXPORT
+#endif
+
+/* This is a global switch to set the compilation for an installed system
+ * (a release build).  It can be set for testing debug builds to ensure that
+ * they will compile when the build type is switched to RC or STABLE, the
+ * default is just to use PNG_LIBPNG_BUILD_BASE_TYPE.  Set this in CPPFLAGS
+ * with either:
+ *
+ *   -DPNG_RELEASE_BUILD Turns on the release compile path
+ *   -DPNG_RELEASE_BUILD=0 Turns it off
+ * or in your pngusr.h with
+ *   #define PNG_RELEASE_BUILD=1 Turns on the release compile path
+ *   #define PNG_RELEASE_BUILD=0 Turns it off
+ */
+#ifndef PNG_RELEASE_BUILD
+#  define PNG_RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
+#endif
+
+/* SECURITY and SAFETY:
+ *
+ * libpng is built with support for internal limits on image dimensions and
+ * memory usage.  These are documented in scripts/pnglibconf.dfa of the
+ * source and recorded in the machine generated header file pnglibconf.h.
+ */
+
+/* If you are running on a machine where you cannot allocate more
+ * than 64K of memory at once, uncomment this.  While libpng will not
+ * normally need that much memory in a chunk (unless you load up a very
+ * large file), zlib needs to know how big of a chunk it can use, and
+ * libpng thus makes sure to check any memory allocation to verify it
+ * will fit into memory.
+ *
+ * zlib provides 'MAXSEG_64K' which, if defined, indicates the
+ * same limit and pngconf.h (already included) sets the limit
+ * if certain operating systems are detected.
+ */
+#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
+#  define PNG_MAX_MALLOC_64K
+#endif
+
+#ifndef PNG_UNUSED
+/* Unused formal parameter warnings are silenced using the following macro
+ * which is expected to have no bad effects on performance (optimizing
+ * compilers will probably remove it entirely).  Note that if you replace
+ * it with something other than whitespace, you must include the terminating
+ * semicolon.
+ */
+#  define PNG_UNUSED(param) (void)param;
+#endif
+
+/* Just a little check that someone hasn't tried to define something
+ * contradictory.
+ */
+#if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
+#  undef PNG_ZBUF_SIZE
+#  define PNG_ZBUF_SIZE 65536L
+#endif
+
+/* If warnings or errors are turned off the code is disabled or redirected here.
+ * From 1.5.4 functions have been added to allow very limited formatting of
+ * error and warning messages - this code will also be disabled here.
+ */
+#ifdef PNG_WARNINGS_SUPPORTED
+#  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
+#else
+#  define png_warning_parameter(p,number,string) ((void)0)
+#  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
+#  define png_warning_parameter_signed(p,number,format,value) ((void)0)
+#  define png_formatted_warning(pp,p,message) ((void)(pp))
+#  define PNG_WARNING_PARAMETERS(p)
+#endif
+#ifndef PNG_ERROR_TEXT_SUPPORTED
+#  define png_fixed_error(s1,s2) png_err(s1)
+#endif
+
+/* Some fixed point APIs are still required even if not exported because
+ * they get used by the corresponding floating point APIs.  This magic
+ * deals with this:
+ */
+#ifdef PNG_FIXED_POINT_SUPPORTED
+#  define PNGFAPI PNGAPI
+#else
+#  define PNGFAPI /* PRIVATE */
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+/* Other defines specific to compilers can go here.  Try to keep
+ * them inside an appropriate ifdef/endif pair for portability.
+ */
+
+/* C allows up-casts from (void*) to any pointer and (const void*) to any
+ * pointer to a const object.  C++ regards this as a type error and requires an
+ * explicit, static, cast and provides the static_cast<> rune to ensure that
+ * const is not cast away.
+ */
+#ifdef __cplusplus
+#  define png_voidcast(type, value) static_cast<type>(value)
+#  define png_constcast(type, value) const_cast<type>(value)
+#  define png_aligncast(type, value) \
+   static_cast<type>(static_cast<void*>(value))
+#  define png_aligncastconst(type, value) \
+   static_cast<type>(static_cast<const void*>(value))
+#else
+#  define png_voidcast(type, value) (value)
+#  ifdef _WIN64
+#     ifdef __GNUC__
+         typedef unsigned long long png_ptruint;
+#     else
+         typedef unsigned __int64 png_ptruint;
+#     endif
+#  else
+      typedef unsigned long png_ptruint;
+#  endif
+#  define png_constcast(type, value) ((type)(png_ptruint)(const void*)(value))
+#  define png_aligncast(type, value) ((void*)(value))
+#  define png_aligncastconst(type, value) ((const void*)(value))
+#endif /* __cplusplus */
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
+    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+   /* png.c requires the following ANSI-C constants if the conversion of
+    * floating point to ASCII is implemented therein:
+    *
+    *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
+    *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
+    *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
+    */
+#  include <float.h>
+
+#  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
+    defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
+   /* We need to check that <math.h> hasn't already been included earlier
+    * as it seems it doesn't agree with <fp.h>, yet we should really use
+    * <fp.h> if possible.
+    */
+#    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
+#      include <fp.h>
+#    endif
+#  else
+#    include <math.h>
+#  endif
+#  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
+   /* Amiga SAS/C: We must include builtin FPU functions when compiling using
+    * MATH=68881
+    */
+#    include <m68881.h>
+#  endif
+#endif
+
+/* This provides the non-ANSI (far) memory allocation routines. */
+#if defined(__TURBOC__) && defined(__MSDOS__)
+#  include <mem.h>
+#  include <alloc.h>
+#endif
+
+#if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
+    defined(_WIN32) || defined(__WIN32__)
+#  include <windows.h>  /* defines _WINDOWS_ macro */
+#endif
+#endif /* PNG_VERSION_INFO_ONLY */
+
+/* Moved here around 1.5.0beta36 from pngconf.h */
+/* Users may want to use these so they are not private.  Any library
+ * functions that are passed far data must be model-independent.
+ */
+
+/* Memory model/platform independent fns */
+#ifndef PNG_ABORT
+#  ifdef _WINDOWS_
+#    define PNG_ABORT() ExitProcess(0)
+#  else
+#    define PNG_ABORT() abort()
+#  endif
+#endif
+
+/* These macros may need to be architecture dependent. */
+#define PNG_ALIGN_NONE   0 /* do not use data alignment */
+#define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
+#ifdef offsetof
+#  define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
+#else
+#  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
+#endif
+#define PNG_ALIGN_SIZE   3 /* use sizeof to determine alignment */
+
+#ifndef PNG_ALIGN_TYPE
+   /* Default to using aligned access optimizations and requiring alignment to a
+    * multiple of the data type size.  Override in a compiler specific fashion
+    * if necessary by inserting tests here:
+    */
+#  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
+#endif
+
+#if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
+   /* This is used because in some compiler implementations non-aligned
+    * structure members are supported, so the offsetof approach below fails.
+    * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
+    * is good for performance.  Do not do this unless you have tested the result
+    * and understand it.
+    */
+#  define png_alignof(type) (sizeof (type))
+#else
+#  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
+#     define png_alignof(type) offsetof(struct{char c; type t;}, t)
+#  else
+#     if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
+#        define png_alignof(type) (1)
+#     endif
+      /* Else leave png_alignof undefined to prevent use thereof */
+#  endif
+#endif
+
+/* This implicitly assumes alignment is always to a power of 2. */
+#ifdef png_alignof
+#  define png_isaligned(ptr, type)\
+   (((type)((const char*)ptr-(const char*)0) & \
+   (type)(png_alignof(type)-1)) == 0)
+#else
+#  define png_isaligned(ptr, type) 0
+#endif
+
+/* End of memory model/platform independent support */
+/* End of 1.5.0beta36 move from pngconf.h */
+
+/* CONSTANTS and UTILITY MACROS
+ * These are used internally by libpng and not exposed in the API
+ */
+
+/* Various modes of operation.  Note that after an init, mode is set to
+ * zero automatically when the structure is created.  Three of these
+ * are defined in png.h because they need to be visible to applications
+ * that call png_set_unknown_chunk().
+ */
+/* #define PNG_HAVE_IHDR            0x01U (defined in png.h) */
+/* #define PNG_HAVE_PLTE            0x02U (defined in png.h) */
+#define PNG_HAVE_IDAT               0x04U
+/* #define PNG_AFTER_IDAT           0x08U (defined in png.h) */
+#define PNG_HAVE_IEND               0x10U
+                   /*               0x20U (unused) */
+                   /*               0x40U (unused) */
+                   /*               0x80U (unused) */
+#define PNG_HAVE_CHUNK_HEADER      0x100U
+#define PNG_WROTE_tIME             0x200U
+#define PNG_WROTE_INFO_BEFORE_PLTE 0x400U
+#define PNG_BACKGROUND_IS_GRAY     0x800U
+#define PNG_HAVE_PNG_SIGNATURE    0x1000U
+#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000U /* Have another chunk after IDAT */
+                   /*             0x4000U (unused) */
+#define PNG_IS_READ_STRUCT        0x8000U /* Else is a write struct */
+
+/* Flags for the transformations the PNG library does on the image data */
+#define PNG_BGR                 0x0001U
+#define PNG_INTERLACE           0x0002U
+#define PNG_PACK                0x0004U
+#define PNG_SHIFT               0x0008U
+#define PNG_SWAP_BYTES          0x0010U
+#define PNG_INVERT_MONO         0x0020U
+#define PNG_QUANTIZE            0x0040U
+#define PNG_COMPOSE             0x0080U    /* Was PNG_BACKGROUND */
+#define PNG_BACKGROUND_EXPAND   0x0100U
+#define PNG_EXPAND_16           0x0200U    /* Added to libpng 1.5.2 */
+#define PNG_16_TO_8             0x0400U    /* Becomes 'chop' in 1.5.4 */
+#define PNG_RGBA                0x0800U
+#define PNG_EXPAND              0x1000U
+#define PNG_GAMMA               0x2000U
+#define PNG_GRAY_TO_RGB         0x4000U
+#define PNG_FILLER              0x8000U
+#define PNG_PACKSWAP           0x10000U
+#define PNG_SWAP_ALPHA         0x20000U
+#define PNG_STRIP_ALPHA        0x40000U
+#define PNG_INVERT_ALPHA       0x80000U
+#define PNG_USER_TRANSFORM    0x100000U
+#define PNG_RGB_TO_GRAY_ERR   0x200000U
+#define PNG_RGB_TO_GRAY_WARN  0x400000U
+#define PNG_RGB_TO_GRAY       0x600000U /* two bits, RGB_TO_GRAY_ERR|WARN */
+#define PNG_ENCODE_ALPHA      0x800000U /* Added to libpng-1.5.4 */
+#define PNG_ADD_ALPHA        0x1000000U /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS      0x2000000U /* Added to libpng-1.2.9 */
+#define PNG_SCALE_16_TO_8    0x4000000U /* Added to libpng-1.5.4 */
+                       /*    0x8000000U unused */
+                       /*   0x10000000U unused */
+                       /*   0x20000000U unused */
+                       /*   0x40000000U unused */
+/* Flags for png_create_struct */
+#define PNG_STRUCT_PNG   0x0001U
+#define PNG_STRUCT_INFO  0x0002U
+
+/* Flags for the png_ptr->flags rather than declaring a byte for each one */
+#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001U
+#define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002U /* Added to libpng-1.6.0 */
+                                  /*      0x0004U    unused */
+#define PNG_FLAG_ZSTREAM_ENDED            0x0008U /* Added to libpng-1.6.0 */
+                                  /*      0x0010U    unused */
+                                  /*      0x0020U    unused */
+#define PNG_FLAG_ROW_INIT                 0x0040U
+#define PNG_FLAG_FILLER_AFTER             0x0080U
+#define PNG_FLAG_CRC_ANCILLARY_USE        0x0100U
+#define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200U
+#define PNG_FLAG_CRC_CRITICAL_USE         0x0400U
+#define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800U
+#define PNG_FLAG_ASSUME_sRGB              0x1000U /* Added to libpng-1.5.4 */
+#define PNG_FLAG_OPTIMIZE_ALPHA           0x2000U /* Added to libpng-1.5.4 */
+#define PNG_FLAG_DETECT_UNINITIALIZED     0x4000U /* Added to libpng-1.5.4 */
+/* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000U */
+/* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000U */
+#define PNG_FLAG_LIBRARY_MISMATCH        0x20000U
+#define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000U
+#define PNG_FLAG_STRIP_ERROR_TEXT        0x80000U
+#define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000U /* Added to libpng-1.4.0 */
+#define PNG_FLAG_APP_WARNINGS_WARN      0x200000U /* Added to libpng-1.6.0 */
+#define PNG_FLAG_APP_ERRORS_WARN        0x400000U /* Added to libpng-1.6.0 */
+                                  /*    0x800000U    unused */
+                                  /*   0x1000000U    unused */
+                                  /*   0x2000000U    unused */
+                                  /*   0x4000000U    unused */
+                                  /*   0x8000000U    unused */
+                                  /*  0x10000000U    unused */
+                                  /*  0x20000000U    unused */
+                                  /*  0x40000000U    unused */
+
+#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
+                                     PNG_FLAG_CRC_ANCILLARY_NOWARN)
+
+#define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
+                                     PNG_FLAG_CRC_CRITICAL_IGNORE)
+
+#define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
+                                     PNG_FLAG_CRC_CRITICAL_MASK)
+
+/* Save typing and make code easier to understand */
+
+#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
+   abs((int)((c1).green) - (int)((c2).green)) + \
+   abs((int)((c1).blue) - (int)((c2).blue)))
+
+/* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
+ * by dividing by 257 *with rounding*.  This macro is exact for the given range.
+ * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
+ * macro were established by experiment (modifying the added value).  The macro
+ * has a second variant that takes a value already scaled by 255 and divides by
+ * 65535 - this has a maximum error of .502.  Over the range 0..65535*65535 it
+ * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
+ */
+#define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
+#define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
+
+/* Added to libpng-1.2.6 JB */
+#define PNG_ROWBYTES(pixel_bits, width) \
+    ((pixel_bits) >= 8 ? \
+    ((size_t)(width) * (((size_t)(pixel_bits)) >> 3)) : \
+    (( ((size_t)(width) * ((size_t)(pixel_bits))) + 7) >> 3) )
+
+/* This returns the number of trailing bits in the last byte of a row, 0 if the
+ * last byte is completely full of pixels.  It is, in principle, (pixel_bits x
+ * width) % 8, but that would overflow for large 'width'.  The second macro is
+ * the same except that it returns the number of unused bits in the last byte;
+ * (8-TRAILBITS), but 0 when TRAILBITS is 0.
+ *
+ * NOTE: these macros are intended to be self-evidently correct and never
+ * overflow on the assumption that pixel_bits is in the range 0..255.  The
+ * arguments are evaluated only once and they can be signed (e.g. as a result of
+ * the integral promotions).  The result of the expression always has type
+ * (png_uint_32), however the compiler always knows it is in the range 0..7.
+ */
+#define PNG_TRAILBITS(pixel_bits, width) \
+    (((pixel_bits) * ((width) % (png_uint_32)8)) % 8)
+
+#define PNG_PADBITS(pixel_bits, width) \
+    ((8 - PNG_TRAILBITS(pixel_bits, width)) % 8)
+
+/* PNG_OUT_OF_RANGE returns true if value is outside the range
+ * ideal-delta..ideal+delta.  Each argument is evaluated twice.
+ * "ideal" and "delta" should be constants, normally simple
+ * integers, "value" a variable. Added to libpng-1.2.6 JB
+ */
+#define PNG_OUT_OF_RANGE(value, ideal, delta) \
+   ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
+
+/* Conversions between fixed and floating point, only defined if
+ * required (to make sure the code doesn't accidentally use float
+ * when it is supposedly disabled.)
+ */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+/* The floating point conversion can't overflow, though it can and
+ * does lose accuracy relative to the original fixed point value.
+ * In practice this doesn't matter because png_fixed_point only
+ * stores numbers with very low precision.  The png_ptr and s
+ * arguments are unused by default but are there in case error
+ * checking becomes a requirement.
+ */
+#define png_float(png_ptr, fixed, s) (.00001 * (fixed))
+
+/* The fixed point conversion performs range checking and evaluates
+ * its argument multiple times, so must be used with care.  The
+ * range checking uses the PNG specification values for a signed
+ * 32-bit fixed point value except that the values are deliberately
+ * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
+ * (2^31-1) * 100000). 's' is a string that describes the value being
+ * converted.
+ *
+ * NOTE: this macro will raise a png_error if the range check fails,
+ * therefore it is normally only appropriate to use this on values
+ * that come from API calls or other sources where an out of range
+ * error indicates a programming error, not a data error!
+ *
+ * NOTE: by default this is off - the macro is not used - because the
+ * function call saves a lot of code.
+ */
+#ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
+#define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
+    ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
+#endif
+/* else the corresponding function is defined below, inside the scope of the
+ * cplusplus test.
+ */
+#endif
+
+/* Constants for known chunk types.  If you need to add a chunk, define the name
+ * here.  For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case.  Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.
+ *
+ * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
+ * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
+ * to be generated if required.
+ *
+ * PNG_32b correctly produces a value shifted by up to 24 bits, even on
+ * architectures where (int) is only 16 bits.
+ */
+#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
+#define PNG_U32(b1,b2,b3,b4) \
+   (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
+
+/* Constants for known chunk types.
+ *
+ * MAINTAINERS: If you need to add a chunk, define the name here.
+ * For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case.  Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.  Please keep the list sorted.
+ *
+ * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
+ * type.  In fact the specification does not express chunk types this way,
+ * however using a 32-bit value means that the chunk type can be read from the
+ * stream using exactly the same code as used for a 32-bit unsigned value and
+ * can be examined far more efficiently (using one arithmetic compare).
+ *
+ * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
+ * libpng API still uses strings for 'unknown' chunks and a macro,
+ * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
+ * that for portable code numeric values must still be used; the string "IHDR"
+ * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
+ *
+ * In 1.7.0 the definitions will be made public in png.h to avoid having to
+ * duplicate the same definitions in application code.
+ */
+#define png_IDAT PNG_U32( 73,  68,  65,  84)
+#define png_IEND PNG_U32( 73,  69,  78,  68)
+#define png_IHDR PNG_U32( 73,  72,  68,  82)
+#define png_PLTE PNG_U32( 80,  76,  84,  69)
+#define png_bKGD PNG_U32( 98,  75,  71,  68)
+#define png_cHRM PNG_U32( 99,  72,  82,  77)
+#define png_eXIf PNG_U32(101,  88,  73, 102) /* registered July 2017 */
+#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
+#define png_gAMA PNG_U32(103,  65,  77,  65)
+#define png_gIFg PNG_U32(103,  73,  70, 103)
+#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
+#define png_gIFx PNG_U32(103,  73,  70, 120)
+#define png_hIST PNG_U32(104,  73,  83,  84)
+#define png_iCCP PNG_U32(105,  67,  67,  80)
+#define png_iTXt PNG_U32(105,  84,  88, 116)
+#define png_oFFs PNG_U32(111,  70,  70, 115)
+#define png_pCAL PNG_U32(112,  67,  65,  76)
+#define png_pHYs PNG_U32(112,  72,  89, 115)
+#define png_sBIT PNG_U32(115,  66,  73,  84)
+#define png_sCAL PNG_U32(115,  67,  65,  76)
+#define png_sPLT PNG_U32(115,  80,  76,  84)
+#define png_sRGB PNG_U32(115,  82,  71,  66)
+#define png_sTER PNG_U32(115,  84,  69,  82)
+#define png_tEXt PNG_U32(116,  69,  88, 116)
+#define png_tIME PNG_U32(116,  73,  77,  69)
+#define png_tRNS PNG_U32(116,  82,  78,  83)
+#define png_zTXt PNG_U32(122,  84,  88, 116)
+
+/* The following will work on (signed char*) strings, whereas the get_uint_32
+ * macro will fail on top-bit-set values because of the sign extension.
+ */
+#define PNG_CHUNK_FROM_STRING(s)\
+   PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])
+
+/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
+ * signed and the argument is a (char[])  This macro will fail miserably on
+ * systems where (char) is more than 8 bits.
+ */
+#define PNG_STRING_FROM_CHUNK(s,c)\
+   (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
+   ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
+   ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
+   ((char*)(s))[3]=(char)((c & 0xff)))
+
+/* Do the same but terminate with a null character. */
+#define PNG_CSTRING_FROM_CHUNK(s,c)\
+   (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
+
+/* Test on flag values as defined in the spec (section 5.4): */
+#define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
+#define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
+#define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
+#define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
+#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
+
+/* Gamma values (new at libpng-1.5.4): */
+#define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
+#define PNG_GAMMA_MAC_INVERSE 65909
+#define PNG_GAMMA_sRGB_INVERSE 45455
+
+/* Almost everything below is C specific; the #defines above can be used in
+ * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
+ */
+#ifndef PNG_VERSION_INFO_ONLY
+
+#include "pngstruct.h"
+#include "pnginfo.h"
+
+/* Validate the include paths - the include path used to generate pnglibconf.h
+ * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
+ */
+#if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
+#  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
+      "-I (include path) error: see the notes in pngpriv.h"
+   /* This means that when pnglibconf.h was built the copy of zlib.h that it
+    * used is not the same as the one being used here.  Because the build of
+    * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
+    * zlib version number and because this affects handling of certain broken
+    * PNG files the -I directives must match.
+    *
+    * The most likely explanation is that you passed a -I in CFLAGS. This will
+    * not work; all the preprocessor directives and in particular all the -I
+    * directives must be in CPPFLAGS.
+    */
+#endif
+
+/* This is used for 16-bit gamma tables -- only the top level pointers are
+ * const; this could be changed:
+ */
+typedef const png_uint_16p * png_const_uint_16pp;
+
+/* Added to libpng-1.5.7: sRGB conversion tables */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
+   /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
+    * 0..65535.  This table gives the closest 16-bit answers (no errors).
+    */
+#endif
+
+PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
+PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
+
+#define PNG_sRGB_FROM_LINEAR(linear) \
+  ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
+   + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
+   /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
+    * encoded value with maximum error 0.646365.  Note that the input is not a
+    * 16-bit value; it has been multiplied by 255! */
+#endif /* SIMPLIFIED_READ/WRITE */
+
+
+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* Internal functions; these are not exported from a DLL however because they
+ * are used within several of the C source files they have to be C extern.
+ *
+ * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
+ */
+
+/* Zlib support */
+#define PNG_UNEXPECTED_ZLIB_RETURN (-7)
+PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
+   PNG_EMPTY);
+   /* Used by the zlib handling functions to ensure that z_stream::msg is always
+    * set before they return.
+    */
+
+#ifdef PNG_WRITE_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
+   png_compression_bufferp *list),PNG_EMPTY);
+   /* Free the buffer list used by the compressed write code. */
+#endif
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
+   !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
+   (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
+   defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
+   (defined(PNG_sCAL_SUPPORTED) && \
+   defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
+   double fp, png_const_charp text),PNG_EMPTY);
+#endif
+
+/* Check the user version string for compatibility, returns false if the version
+ * numbers aren't compatible.
+ */
+PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
+   png_const_charp user_png_ver),PNG_EMPTY);
+
+/* Internal base allocator - no messages, NULL on failure to allocate.  This
+ * does, however, call the application provided allocator and that could call
+ * png_error (although that would be a bug in the application implementation.)
+ */
+PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
+   png_alloc_size_t size),PNG_ALLOCATED);
+
+#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
+   defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
+/* Internal array allocator, outputs no error or warning messages on failure,
+ * just returns NULL.
+ */
+PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
+   int nelements, size_t element_size),PNG_ALLOCATED);
+
+/* The same but an existing array is extended by add_elements.  This function
+ * also memsets the new elements to 0 and copies the old elements.  The old
+ * array is not freed or altered.
+ */
+PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
+   png_const_voidp array, int old_elements, int add_elements,
+   size_t element_size),PNG_ALLOCATED);
+#endif /* text, sPLT or unknown chunks */
+
+/* Magic to create a struct when there is no struct to call the user supplied
+ * memory allocators.  Because error handling has not been set up the memory
+ * handlers can't safely call png_error, but this is an obscure and undocumented
+ * restriction so libpng has to assume that the 'free' handler, at least, might
+ * call png_error.
+ */
+PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
+   (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+    png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
+    png_free_ptr free_fn),PNG_ALLOCATED);
+
+/* Free memory from internal libpng struct */
+PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
+   PNG_EMPTY);
+
+/* Free an allocated jmp_buf (always succeeds) */
+PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
+
+/* Function to allocate memory for zlib.  PNGAPI is disallowed. */
+PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
+   PNG_ALLOCATED);
+
+/* Function to free memory for zlib.  PNGAPI is disallowed. */
+PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
+
+/* Next four functions are used internally as callbacks.  PNGCBAPI is required
+ * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
+ * PNGCBAPI at 1.5.0
+ */
+
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
+    png_bytep data, size_t length),PNG_EMPTY);
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
+    png_bytep buffer, size_t length),PNG_EMPTY);
+#endif
+
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
+    png_bytep data, size_t length),PNG_EMPTY);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+#  ifdef PNG_STDIO_SUPPORTED
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
+   PNG_EMPTY);
+#  endif
+#endif
+
+/* Reset the CRC variable */
+PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
+
+/* Write the "data" buffer to whatever output you are using */
+PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
+    png_const_bytep data, size_t length),PNG_EMPTY);
+
+/* Read and check the PNG file signature */
+PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
+   png_inforp info_ptr),PNG_EMPTY);
+
+/* Read the chunk header (length + type name) */
+PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
+   PNG_EMPTY);
+
+/* Read data from whatever input you are using into the "data" buffer */
+PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
+    size_t length),PNG_EMPTY);
+
+/* Read bytes into buf, and update png_ptr->crc */
+PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
+    png_uint_32 length),PNG_EMPTY);
+
+/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
+PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
+   png_uint_32 skip),PNG_EMPTY);
+
+/* Read the CRC from the file and compare it to the libpng calculated CRC */
+PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
+
+/* Calculate the CRC over a section of data.  Note that we are only
+ * passing a maximum of 64K on systems that have this as a memory limit,
+ * since this is the maximum buffer size we can specify.
+ */
+PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
+   png_const_bytep ptr, size_t length),PNG_EMPTY);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
+#endif
+
+/* Write various chunks */
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information.
+ */
+PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
+   png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
+   int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
+   png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
+   png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
+   PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
+
+#ifdef PNG_WRITE_gAMA_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
+    png_fixed_point file_gamma),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
+    png_const_color_8p sbit, int color_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_cHRM_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
+    const png_xy *xy), PNG_EMPTY);
+   /* The xy value must have been previously validated */
+#endif
+
+#ifdef PNG_WRITE_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
+    int intent),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_eXIf_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_eXIf,(png_structrp png_ptr,
+    png_bytep exif, int num_exif),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
+   png_const_charp name, png_const_bytep profile), PNG_EMPTY);
+   /* The profile must have been previously validated for correctness, the
+    * length comes from the first four bytes.  Only the base, deflate,
+    * compression is supported.
+    */
+#endif
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
+    png_const_sPLT_tp palette),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
+    png_const_bytep trans, png_const_color_16p values, int number,
+    int color_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
+    png_const_color_16p values, int color_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
+    png_const_uint_16p hist, int num_hist),PNG_EMPTY);
+#endif
+
+/* Chunks that have keywords */
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
+   png_const_charp key, png_const_charp text, size_t text_len),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
+    key, png_const_charp text, int compression),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
+    int compression, png_const_charp key, png_const_charp lang,
+    png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
+PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
+    png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
+    png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
+    png_const_charp units, png_charpp params),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
+    png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
+    int unit_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
+    png_const_timep mod_time),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
+    int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
+#endif
+
+/* Called when finished processing a row of data */
+PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
+    PNG_EMPTY);
+
+/* Internal use only.   Called before first row of data */
+PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
+    PNG_EMPTY);
+
+/* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
+ * array of png_ptr->width pixels.  If the image is not interlaced or this
+ * is the final pass this just does a memcpy, otherwise the "display" flag
+ * is used to determine whether to copy pixels that are not in the current pass.
+ *
+ * Because 'png_do_read_interlace' (below) replicates pixels this allows this
+ * function to achieve the documented 'blocky' appearance during interlaced read
+ * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
+ * are not changed if they are not in the current pass, when display is 0.
+ *
+ * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
+ *
+ * The API always reads from the png_struct row buffer and always assumes that
+ * it is full width (png_do_read_interlace has already been called.)
+ *
+ * This function is only ever used to write to row buffers provided by the
+ * caller of the relevant libpng API and the row must have already been
+ * transformed by the read transformations.
+ *
+ * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
+ * bitmasks for use within the code, otherwise runtime generated masks are used.
+ * The default is compile time masks.
+ */
+#ifndef PNG_USE_COMPILE_TIME_MASKS
+#  define PNG_USE_COMPILE_TIME_MASKS 1
+#endif
+PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
+    png_bytep row, int display),PNG_EMPTY);
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* Expand an interlaced row: the 'row_info' describes the pass data that has
+ * been read in and must correspond to the pixels in 'row', the pixels are
+ * expanded (moved apart) in 'row' to match the final layout, when doing this
+ * the pixels are *replicated* to the intervening space.  This is essential for
+ * the correct operation of png_combine_row, above.
+ */
+PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
+    png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
+#endif
+
+/* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+/* Grab pixels out of a row for an interlaced pass */
+PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
+    png_bytep row, int pass),PNG_EMPTY);
+#endif
+
+/* Unfilter a row: check the filter value before calling this, there is no point
+ * calling it for PNG_FILTER_VALUE_NONE.
+ */
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
+
+#if PNG_ARM_NEON_OPT > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
+    png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+#if PNG_MIPS_MSA_OPT > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_msa,(png_row_infop row_info,
+    png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+#if PNG_POWERPC_VSX_OPT > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_vsx,(png_row_infop row_info,
+    png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+#if PNG_INTEL_SSE_IMPLEMENTATION > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+/* Choose the best filter to use and filter the row data */
+PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
+    png_row_infop row_info),PNG_EMPTY);
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
+   png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
+   /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
+    * is NULL the function checks, instead, for the end of the stream.  In this
+    * case a benign error will be issued if the stream end is not found or if
+    * extra data has to be consumed.
+    */
+PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
+   PNG_EMPTY);
+   /* This cleans up when the IDAT LZ stream does not end when the last image
+    * byte is read; there is still some pending input.
+    */
+
+PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
+   PNG_EMPTY);
+   /* Finish a row while reading, dealing with interlacing passes, etc. */
+#endif /* SEQUENTIAL_READ */
+
+/* Initialize the row buffers, etc. */
+PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
+
+#if ZLIB_VERNUM >= 0x1240
+PNG_INTERNAL_FUNCTION(int,png_zlib_inflate,(png_structrp png_ptr, int flush),
+      PNG_EMPTY);
+#  define PNG_INFLATE(pp, flush) png_zlib_inflate(pp, flush)
+#else /* Zlib < 1.2.4 */
+#  define PNG_INFLATE(pp, flush) inflate(&(pp)->zstream, flush)
+#endif /* Zlib < 1.2.4 */
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Optional call to update the users info structure */
+PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+#endif
+
+/* Shared transform functions, defined in pngtran.c */
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
+    png_bytep row, int at_start),PNG_EMPTY);
+#endif
+
+#ifdef PNG_16BIT_SUPPORTED
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
+    png_bytep row),PNG_EMPTY);
+#endif
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
+    defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
+    png_bytep row),PNG_EMPTY);
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
+    png_bytep row),PNG_EMPTY);
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
+    png_bytep row),PNG_EMPTY);
+#endif
+
+/* The following decodes the appropriate chunks, and does error correction,
+ * then calls the appropriate callback for the chunk if it is valid.
+ */
+
+/* Decode the IHDR chunk */
+PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_eXIf_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_eXIf,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif /* READ_iCCP */
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif /* READ_sPLT */
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_const_structrp png_ptr,
+    png_uint_32 chunk_name),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_check_chunk_length,(png_const_structrp png_ptr,
+    png_uint_32 chunk_length),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
+   /* This is the function that gets called for unknown chunks.  The 'keep'
+    * argument is either non-zero for a known chunk that has been set to be
+    * handled as unknown or zero for an unknown chunk.  By default the function
+    * just skips the chunk or errors out if it is critical.
+    */
+
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
+    defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
+    (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
+   /* Exactly as the API png_handle_as_unknown() except that the argument is a
+    * 32-bit chunk name, not a string.
+    */
+#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
+
+/* Handle the transformations for reading and writing */
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
+   png_row_infop row_info),PNG_EMPTY);
+#endif
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
+   png_row_infop row_info),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
+    PNG_EMPTY);
+#endif
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
+    PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
+    png_bytep buffer, size_t buffer_length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
+    png_bytep buffer, size_t buffer_length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
+    PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
+   png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
+   png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
+   png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
+    png_bytep row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
+    PNG_EMPTY);
+#  ifdef PNG_READ_tEXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+#  endif
+#  ifdef PNG_READ_zTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+#  endif
+#  ifdef PNG_READ_iTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+#  endif
+
+#endif /* PROGRESSIVE_READ */
+
+/* Added at libpng version 1.6.0 */
+#ifdef PNG_GAMMA_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
+   /* Set the colorspace gamma with a value provided by the application or by
+    * the gAMA chunk on read.  The value will override anything set by an ICC
+    * profile.
+    */
+
+PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
+    png_inforp info_ptr), PNG_EMPTY);
+   /* Synchronize the info 'valid' flags with the colorspace */
+
+PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
+    png_inforp info_ptr), PNG_EMPTY);
+   /* Copy the png_struct colorspace to the info_struct and call the above to
+    * synchronize the flags.  Checks for NULL info_ptr and does nothing.
+    */
+#endif
+
+/* Added at libpng version 1.4.0 */
+#ifdef PNG_COLORSPACE_SUPPORTED
+/* These internal functions are for maintaining the colorspace structure within
+ * a png_info or png_struct (or, indeed, both).
+ */
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
+   (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
+    int preferred), PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
+   (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
+    int preferred), PNG_EMPTY);
+
+#ifdef PNG_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, int intent), PNG_EMPTY);
+   /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
+    * flags to write them, if it returns false there was a problem and an error
+    * message has already been output (but the colorspace may still need to be
+    * synced to record the invalid flag).
+    */
+#endif /* sRGB */
+
+#ifdef PNG_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, png_const_charp name,
+   png_uint_32 profile_length, png_const_bytep profile, int color_type),
+   PNG_EMPTY);
+   /* The 'name' is used for information only */
+
+/* Routines for checking parts of an ICC profile. */
+#ifdef PNG_READ_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, png_const_charp name,
+   png_uint_32 profile_length), PNG_EMPTY);
+#endif /* READ_iCCP */
+PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, png_const_charp name,
+   png_uint_32 profile_length,
+   png_const_bytep profile /* first 132 bytes only */, int color_type),
+   PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, png_const_charp name,
+   png_uint_32 profile_length,
+   png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
+#ifdef PNG_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
+   png_const_structrp png_ptr, png_colorspacerp colorspace,
+   png_const_bytep profile, uLong adler), PNG_EMPTY);
+   /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
+    * be zero to indicate that it is not available.  It is used, if provided,
+    * as a fast check on the profile when checking to see if it is sRGB.
+    */
+#endif
+#endif /* iCCP */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
+   (png_structrp png_ptr), PNG_EMPTY);
+   /* Set the rgb_to_gray coefficients from the colorspace Y values */
+#endif /* READ_RGB_TO_GRAY */
+#endif /* COLORSPACE */
+
+/* Added at libpng version 1.4.0 */
+PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
+    png_uint_32 width, png_uint_32 height, int bit_depth,
+    int color_type, int interlace_type, int compression_type,
+    int filter_type),PNG_EMPTY);
+
+/* Added at libpng version 1.5.10 */
+#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
+    defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
+   (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
+#endif
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
+   png_const_charp name),PNG_NORETURN);
+#endif
+
+/* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
+ * the end.  Always leaves the buffer nul terminated.  Never errors out (and
+ * there is no error code.)
+ */
+PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
+   size_t pos, png_const_charp string),PNG_EMPTY);
+
+/* Various internal functions to handle formatted warning messages, currently
+ * only implemented for warnings.
+ */
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string.  This utility only
+ * does unsigned values.
+ */
+PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
+   png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
+
+/* Convenience macro that takes an array: */
+#define PNG_FORMAT_NUMBER(buffer,format,number) \
+   png_format_number(buffer, buffer + (sizeof buffer), format, number)
+
+/* Suggested size for a number buffer (enough for 64 bits and a sign!) */
+#define PNG_NUMBER_BUFFER_SIZE 24
+
+/* These are the integer formats currently supported, the name is formed from
+ * the standard printf(3) format string.
+ */
+#define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
+#define PNG_NUMBER_FORMAT_02u   2
+#define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
+#define PNG_NUMBER_FORMAT_02d   2
+#define PNG_NUMBER_FORMAT_x     3
+#define PNG_NUMBER_FORMAT_02x   4
+#define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* New defines and members adding in libpng-1.5.4 */
+#  define PNG_WARNING_PARAMETER_SIZE 32
+#  define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
+
+/* An l-value of this type has to be passed to the APIs below to cache the
+ * values of the parameters to a formatted warning message.
+ */
+typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
+   PNG_WARNING_PARAMETER_SIZE];
+
+PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
+   int number, png_const_charp string),PNG_EMPTY);
+   /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
+    * including the trailing '\0'.
+    */
+PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
+   (png_warning_parameters p, int number, int format, png_alloc_size_t value),
+   PNG_EMPTY);
+   /* Use png_alloc_size_t because it is an unsigned type as big as any we
+    * need to output.  Use the following for a signed value.
+    */
+PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
+   (png_warning_parameters p, int number, int format, png_int_32 value),
+   PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
+   png_warning_parameters p, png_const_charp message),PNG_EMPTY);
+   /* 'message' follows the X/Open approach of using @1, @2 to insert
+    * parameters previously supplied using the above functions.  Errors in
+    * specifying the parameters will simply result in garbage substitutions.
+    */
+#endif
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+/* Application errors (new in 1.6); use these functions (declared below) for
+ * errors in the parameters or order of API function calls on read.  The
+ * 'warning' should be used for an error that can be handled completely; the
+ * 'error' for one which can be handled safely but which may lose application
+ * information or settings.
+ *
+ * By default these both result in a png_error call prior to release, while in a
+ * released version the 'warning' is just a warning.  However if the application
+ * explicitly disables benign errors (explicitly permitting the code to lose
+ * information) they both turn into warnings.
+ *
+ * If benign errors aren't supported they end up as the corresponding base call
+ * (png_warning or png_error.)
+ */
+PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
+   png_const_charp message),PNG_EMPTY);
+   /* The application provided invalid parameters to an API function or called
+    * an API function at the wrong time, libpng can completely recover.
+    */
+
+PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
+   png_const_charp message),PNG_EMPTY);
+   /* As above but libpng will ignore the call, or attempt some other partial
+    * recovery from the error.
+    */
+#else
+#  define png_app_warning(pp,s) png_warning(pp,s)
+#  define png_app_error(pp,s) png_error(pp,s)
+#endif
+
+PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
+   png_const_charp message, int error),PNG_EMPTY);
+   /* Report a recoverable issue in chunk data.  On read this is used to report
+    * a problem found while reading a particular chunk and the
+    * png_chunk_benign_error or png_chunk_warning function is used as
+    * appropriate.  On write this is used to report an error that comes from
+    * data set via an application call to a png_set_ API and png_app_error or
+    * png_app_warning is used as appropriate.
+    *
+    * The 'error' parameter must have one of the following values:
+    */
+#define PNG_CHUNK_WARNING     0 /* never an error */
+#define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
+#define PNG_CHUNK_ERROR       2 /* always an error */
+
+/* ASCII to FP interfaces, currently only implemented if sCAL
+ * support is required.
+ */
+#if defined(PNG_sCAL_SUPPORTED)
+/* MAX_DIGITS is actually the maximum number of characters in an sCAL
+ * width or height, derived from the precision (number of significant
+ * digits - a build time settable option) and assumptions about the
+ * maximum ridiculous exponent.
+ */
+#define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
+   png_charp ascii, size_t size, double fp, unsigned int precision),
+   PNG_EMPTY);
+#endif /* FLOATING_POINT */
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
+   png_charp ascii, size_t size, png_fixed_point fp),PNG_EMPTY);
+#endif /* FIXED_POINT */
+#endif /* sCAL */
+
+#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
+/* An internal API to validate the format of a floating point number.
+ * The result is the index of the next character.  If the number is
+ * not valid it will be the index of a character in the supposed number.
+ *
+ * The format of a number is defined in the PNG extensions specification
+ * and this API is strictly conformant to that spec, not anyone elses!
+ *
+ * The format as a regular expression is:
+ *
+ * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
+ *
+ * or:
+ *
+ * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
+ *
+ * The complexity is that either integer or fraction must be present and the
+ * fraction is permitted to have no digits only if the integer is present.
+ *
+ * NOTE: The dangling E problem.
+ *   There is a PNG valid floating point number in the following:
+ *
+ *       PNG floating point numbers are not greedy.
+ *
+ *   Working this out requires *TWO* character lookahead (because of the
+ *   sign), the parser does not do this - it will fail at the 'r' - this
+ *   doesn't matter for PNG sCAL chunk values, but it requires more care
+ *   if the value were ever to be embedded in something more complex.  Use
+ *   ANSI-C strtod if you need the lookahead.
+ */
+/* State table for the parser. */
+#define PNG_FP_INTEGER    0  /* before or in integer */
+#define PNG_FP_FRACTION   1  /* before or in fraction */
+#define PNG_FP_EXPONENT   2  /* before or in exponent */
+#define PNG_FP_STATE      3  /* mask for the above */
+#define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
+#define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
+#define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
+#define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
+#define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
+
+/* These three values don't affect the parser.  They are set but not used.
+ */
+#define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
+#define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
+#define PNG_FP_NONZERO  256  /* A non-zero value */
+#define PNG_FP_STICKY   448  /* The above three flags */
+
+/* This is available for the caller to store in 'state' if required.  Do not
+ * call the parser after setting it (the parser sometimes clears it.)
+ */
+#define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
+
+/* Result codes for the parser (boolean - true meants ok, false means
+ * not ok yet.)
+ */
+#define PNG_FP_MAYBE      0  /* The number may be valid in the future */
+#define PNG_FP_OK         1  /* The number is valid */
+
+/* Tests on the sticky non-zero and negative flags.  To pass these checks
+ * the state must also indicate that the whole number is valid - this is
+ * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
+ * is equivalent to PNG_FP_OK above.)
+ */
+#define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
+   /* NZ_MASK: the string is valid and a non-zero negative value */
+#define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
+   /* Z MASK: the string is valid and a non-zero value. */
+   /* PNG_FP_SAW_DIGIT: the string is valid. */
+#define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
+#define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
+#define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
+
+/* The actual parser.  This can be called repeatedly. It updates
+ * the index into the string and the state variable (which must
+ * be initialized to 0).  It returns a result code, as above.  There
+ * is no point calling the parser any more if it fails to advance to
+ * the end of the string - it is stuck on an invalid character (or
+ * terminated by '\0').
+ *
+ * Note that the pointer will consume an E or even an E+ and then leave
+ * a 'maybe' state even though a preceding integer.fraction is valid.
+ * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
+ * a valid number.  It's possible to recover from this by calling
+ * the parser again (from the start, with state 0) but with a string
+ * that omits the last character (i.e. set the size to the index of
+ * the problem character.)  This has not been tested within libpng.
+ */
+PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
+   size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
+
+/* This is the same but it checks a complete string and returns true
+ * only if it just contains a floating point number.  As of 1.5.4 this
+ * function also returns the state at the end of parsing the number if
+ * it was valid (otherwise it returns 0.)  This can be used for testing
+ * for negative or zero values using the sticky flag.
+ */
+PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
+   size_t size),PNG_EMPTY);
+#endif /* pCAL || sCAL */
+
+#if defined(PNG_GAMMA_SUPPORTED) ||\
+    defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
+/* Added at libpng version 1.5.0 */
+/* This is a utility to provide a*times/div (rounded) and indicate
+ * if there is an overflow.  The result is a boolean - false (0)
+ * for overflow, true (1) if no overflow, in which case *res
+ * holds the result.
+ */
+PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
+   png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+/* Same deal, but issue a warning on overflow and return 0. */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
+   (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
+   png_int_32 divided_by),PNG_EMPTY);
+#endif
+
+#ifdef PNG_GAMMA_SUPPORTED
+/* Calculate a reciprocal - used for gamma values.  This returns
+ * 0 if the argument is 0 in order to maintain an undefined value;
+ * there are no warnings.
+ */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
+   PNG_EMPTY);
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* The same but gives a reciprocal of the product of two fixed point
+ * values.  Accuracy is suitable for gamma calculations but this is
+ * not exact - use png_muldiv for that.  Only required at present on read.
+ */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
+   png_fixed_point b),PNG_EMPTY);
+#endif
+
+/* Return true if the gamma value is significantly different from 1.0 */
+PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
+   PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Internal fixed point gamma correction.  These APIs are called as
+ * required to convert single values - they don't need to be fast,
+ * they are not used when processing image pixel values.
+ *
+ * While the input is an 'unsigned' value it must actually be the
+ * correct bit value - 0..255 or 0..65535 as required.
+ */
+PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
+   unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
+   png_fixed_point gamma_value),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
+   png_fixed_point gamma_value),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
+   PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
+   int bit_depth),PNG_EMPTY);
+#endif
+
+/* SIMPLIFIED READ/WRITE SUPPORT */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+/* The internal structure that png_image::opaque points to. */
+typedef struct png_control
+{
+   png_structp png_ptr;
+   png_infop   info_ptr;
+   png_voidp   error_buf;           /* Always a jmp_buf at present. */
+
+   png_const_bytep memory;          /* Memory buffer. */
+   size_t          size;            /* Size of the memory buffer. */
+
+   unsigned int for_write       :1; /* Otherwise it is a read structure */
+   unsigned int owned_file      :1; /* We own the file in io_ptr */
+} png_control;
+
+/* Return the pointer to the jmp_buf from a png_control: necessary because C
+ * does not reveal the type of the elements of jmp_buf.
+ */
+#ifdef __cplusplus
+#  define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
+#else
+#  define png_control_jmp_buf(pc) ((pc)->error_buf)
+#endif
+
+/* Utility to safely execute a piece of libpng code catching and logging any
+ * errors that might occur.  Returns true on success, false on failure (either
+ * of the function or as a result of a png_error.)
+ */
+PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
+   png_const_charp error_message),PNG_NORETURN);
+
+#ifdef PNG_WARNINGS_SUPPORTED
+PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
+   png_const_charp warning_message),PNG_EMPTY);
+#else
+#  define png_safe_warning 0/*dummy argument*/
+#endif
+
+PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
+   int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
+
+/* Utility to log an error; this also cleans up the png_image; the function
+ * always returns 0 (false).
+ */
+PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
+   png_const_charp error_message),PNG_EMPTY);
+
+#ifndef PNG_SIMPLIFIED_READ_SUPPORTED
+/* png_image_free is used by the write code but not exported */
+PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
+#endif /* !SIMPLIFIED_READ */
+
+#endif /* SIMPLIFIED READ/WRITE */
+
+/* These are initialization functions for hardware specific PNG filter
+ * optimizations; list these here then select the appropriate one at compile
+ * time using the macro PNG_FILTER_OPTIMIZATIONS.  If the macro is not defined
+ * the generic code is used.
+ */
+#ifdef PNG_FILTER_OPTIMIZATIONS
+PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
+   unsigned int bpp), PNG_EMPTY);
+   /* Just declare the optimization that will be used */
+#else
+   /* List *all* the possible optimizations here - this branch is required if
+    * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
+    * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
+    */
+#  if PNG_ARM_NEON_OPT > 0
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
+   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#endif
+
+#if PNG_MIPS_MSA_OPT > 0
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_msa,
+   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#endif
+
+#  if PNG_INTEL_SSE_IMPLEMENTATION > 0
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_sse2,
+   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#  endif
+#endif
+
+PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
+   png_const_charp key, png_bytep new_key), PNG_EMPTY);
+
+#if PNG_ARM_NEON_IMPLEMENTATION == 1
+PNG_INTERNAL_FUNCTION(void,
+                      png_riffle_palette_neon,
+                      (png_structrp),
+                      PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(int,
+                      png_do_expand_palette_rgba8_neon,
+                      (png_structrp,
+                       png_row_infop,
+                       png_const_bytep,
+                       const png_bytepp,
+                       const png_bytepp),
+                      PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(int,
+                      png_do_expand_palette_rgb8_neon,
+                      (png_structrp,
+                       png_row_infop,
+                       png_const_bytep,
+                       const png_bytepp,
+                       const png_bytepp),
+                      PNG_EMPTY);
+#endif
+
+/* Maintainer: Put new private prototypes here ^ */
+
+#include "pngdebug.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PNG_VERSION_INFO_ONLY */
+#endif /* PNGPRIV_H */
diff --git a/extern/libpng/pngread.c b/extern/libpng/pngread.c
new file mode 100644
index 0000000000..8fa7d9f162
--- /dev/null
+++ b/extern/libpng/pngread.c
@@ -0,0 +1,4225 @@
+
+/* pngread.c - read a PNG file
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file contains routines that an application calls directly to
+ * read a PNG file or stream.
+ */
+
+#include "pngpriv.h"
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
+#  include <errno.h>
+#endif
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Create a PNG structure for reading, and allocate any memory needed. */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
+{
+#ifndef PNG_USER_MEM_SUPPORTED
+   png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+        error_fn, warn_fn, NULL, NULL, NULL);
+#else
+   return png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
+        warn_fn, NULL, NULL, NULL);
+}
+
+/* Alternate create PNG structure for reading, and allocate any memory
+ * needed.
+ */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
+{
+   png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+       error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
+#endif /* USER_MEM */
+
+   if (png_ptr != NULL)
+   {
+      png_ptr->mode = PNG_IS_READ_STRUCT;
+
+      /* Added in libpng-1.6.0; this can be used to detect a read structure if
+       * required (it will be zero in a write structure.)
+       */
+#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+         png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE;
+#     endif
+
+#     ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED
+         png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
+
+         /* In stable builds only warn if an application error can be completely
+          * handled.
+          */
+#        if PNG_RELEASE_BUILD
+            png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
+#        endif
+#     endif
+
+      /* TODO: delay this, it can be done in png_init_io (if the app doesn't
+       * do it itself) avoiding setting the default function if it is not
+       * required.
+       */
+      png_set_read_fn(png_ptr, NULL, NULL);
+   }
+
+   return png_ptr;
+}
+
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the information before the actual image data.  This has been
+ * changed in v0.90 to allow reading a file that already has the magic
+ * bytes read from the stream.  You can tell libpng how many bytes have
+ * been read from the beginning of the stream (up to the maximum of 8)
+ * via png_set_sig_bytes(), and we will only check the remaining bytes
+ * here.  The application can then have access to the signature bytes we
+ * read if it is determined that this isn't a valid PNG file.
+ */
+void PNGAPI
+png_read_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   int keep;
+#endif
+
+   png_debug(1, "in png_read_info");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* Read and check the PNG file signature. */
+   png_read_sig(png_ptr, info_ptr);
+
+   for (;;)
+   {
+      png_uint_32 length = png_read_chunk_header(png_ptr);
+      png_uint_32 chunk_name = png_ptr->chunk_name;
+
+      /* IDAT logic needs to happen here to simplify getting the two flags
+       * right.
+       */
+      if (chunk_name == png_IDAT)
+      {
+         if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+            png_chunk_error(png_ptr, "Missing IHDR before IDAT");
+
+         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+             (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+            png_chunk_error(png_ptr, "Missing PLTE before IDAT");
+
+         else if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+            png_chunk_benign_error(png_ptr, "Too many IDATs found");
+
+         png_ptr->mode |= PNG_HAVE_IDAT;
+      }
+
+      else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      {
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+         png_ptr->mode |= PNG_AFTER_IDAT;
+      }
+
+      /* This should be a binary subdivision search or a hash for
+       * matching the chunk name rather than a linear search.
+       */
+      if (chunk_name == png_IHDR)
+         png_handle_IHDR(png_ptr, info_ptr, length);
+
+      else if (chunk_name == png_IEND)
+         png_handle_IEND(png_ptr, info_ptr, length);
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+      {
+         png_handle_unknown(png_ptr, info_ptr, length, keep);
+
+         if (chunk_name == png_PLTE)
+            png_ptr->mode |= PNG_HAVE_PLTE;
+
+         else if (chunk_name == png_IDAT)
+         {
+            png_ptr->idat_size = 0; /* It has been consumed */
+            break;
+         }
+      }
+#endif
+      else if (chunk_name == png_PLTE)
+         png_handle_PLTE(png_ptr, info_ptr, length);
+
+      else if (chunk_name == png_IDAT)
+      {
+         png_ptr->idat_size = length;
+         break;
+      }
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+      else if (chunk_name == png_bKGD)
+         png_handle_bKGD(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+      else if (chunk_name == png_cHRM)
+         png_handle_cHRM(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_eXIf_SUPPORTED
+      else if (chunk_name == png_eXIf)
+         png_handle_eXIf(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+      else if (chunk_name == png_gAMA)
+         png_handle_gAMA(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+      else if (chunk_name == png_hIST)
+         png_handle_hIST(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+      else if (chunk_name == png_oFFs)
+         png_handle_oFFs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+      else if (chunk_name == png_pCAL)
+         png_handle_pCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+      else if (chunk_name == png_sCAL)
+         png_handle_sCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+      else if (chunk_name == png_pHYs)
+         png_handle_pHYs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+      else if (chunk_name == png_sBIT)
+         png_handle_sBIT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+      else if (chunk_name == png_sRGB)
+         png_handle_sRGB(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+      else if (chunk_name == png_iCCP)
+         png_handle_iCCP(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+      else if (chunk_name == png_sPLT)
+         png_handle_sPLT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+      else if (chunk_name == png_tEXt)
+         png_handle_tEXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+      else if (chunk_name == png_tIME)
+         png_handle_tIME(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+      else if (chunk_name == png_tRNS)
+         png_handle_tRNS(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+      else if (chunk_name == png_zTXt)
+         png_handle_zTXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+      else if (chunk_name == png_iTXt)
+         png_handle_iTXt(png_ptr, info_ptr, length);
+#endif
+
+      else
+         png_handle_unknown(png_ptr, info_ptr, length,
+             PNG_HANDLE_CHUNK_AS_DEFAULT);
+   }
+}
+#endif /* SEQUENTIAL_READ */
+
+/* Optional call to update the users info_ptr structure */
+void PNGAPI
+png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+   png_debug(1, "in png_read_update_info");
+
+   if (png_ptr != NULL)
+   {
+      if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+      {
+         png_read_start_row(png_ptr);
+
+#        ifdef PNG_READ_TRANSFORMS_SUPPORTED
+            png_read_transform_info(png_ptr, info_ptr);
+#        else
+            PNG_UNUSED(info_ptr)
+#        endif
+      }
+
+      /* New in 1.6.0 this avoids the bug of doing the initializations twice */
+      else
+         png_app_error(png_ptr,
+             "png_read_update_info/png_start_read_image: duplicate call");
+   }
+}
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Initialize palette, background, etc, after transformations
+ * are set, but before any reading takes place.  This allows
+ * the user to obtain a gamma-corrected palette, for example.
+ * If the user doesn't call this, we will do it ourselves.
+ */
+void PNGAPI
+png_start_read_image(png_structrp png_ptr)
+{
+   png_debug(1, "in png_start_read_image");
+
+   if (png_ptr != NULL)
+   {
+      if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+         png_read_start_row(png_ptr);
+
+      /* New in 1.6.0 this avoids the bug of doing the initializations twice */
+      else
+         png_app_error(png_ptr,
+             "png_start_read_image/png_read_update_info: duplicate call");
+   }
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Undoes intrapixel differencing,
+ * NOTE: this is apparently only supported in the 'sequential' reader.
+ */
+static void
+png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_read_intrapixel");
+
+   if (
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      int bytes_per_pixel;
+      png_uint_32 row_width = row_info->width;
+
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 3;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 4;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
+            *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
+         }
+      }
+      else if (row_info->bit_depth == 16)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 6;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 8;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            png_uint_32 s0   = (png_uint_32)(*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 red  = (s0 + s1 + 65536) & 0xffff;
+            png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
+            *(rp    ) = (png_byte)((red >> 8) & 0xff);
+            *(rp + 1) = (png_byte)(red & 0xff);
+            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
+            *(rp + 5) = (png_byte)(blue & 0xff);
+         }
+      }
+   }
+}
+#endif /* MNG_FEATURES */
+
+void PNGAPI
+png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
+{
+   png_row_info row_info;
+
+   if (png_ptr == NULL)
+      return;
+
+   png_debug2(1, "in png_read_row (row %lu, pass %d)",
+       (unsigned long)png_ptr->row_number, png_ptr->pass);
+
+   /* png_read_start_row sets the information (in particular iwidth) for this
+    * interlace pass.
+    */
+   if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+      png_read_start_row(png_ptr);
+
+   /* 1.5.6: row_info moved out of png_struct to a local here. */
+   row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
+   row_info.color_type = png_ptr->color_type;
+   row_info.bit_depth = png_ptr->bit_depth;
+   row_info.channels = png_ptr->channels;
+   row_info.pixel_depth = png_ptr->pixel_depth;
+   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+#ifdef PNG_WARNINGS_SUPPORTED
+   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
+   {
+   /* Check for transforms that have been set but were defined out */
+#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+      png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
+      png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
+    !defined(PNG_READ_PACKSWAP_SUPPORTED)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+      png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
+      png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
+      png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
+      png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+      png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
+#endif
+   }
+#endif /* WARNINGS */
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* If interlaced and we do not need a new row, combine row and return.
+    * Notice that the pixels we have from previous rows have been transformed
+    * already; we can only combine like with like (transformed or
+    * untransformed) and, because of the libpng API for interlaced images, this
+    * means we must transform before de-interlacing.
+    */
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      switch (png_ptr->pass)
+      {
+         case 0:
+            if (png_ptr->row_number & 0x07)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 1:
+            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 2:
+            if ((png_ptr->row_number & 0x07) != 4)
+            {
+               if (dsp_row != NULL && (png_ptr->row_number & 4))
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 3:
+            if ((png_ptr->row_number & 3) || png_ptr->width < 3)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 4:
+            if ((png_ptr->row_number & 3) != 2)
+            {
+               if (dsp_row != NULL && (png_ptr->row_number & 2))
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 5:
+            if ((png_ptr->row_number & 1) || png_ptr->width < 2)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         default:
+         case 6:
+            if ((png_ptr->row_number & 1) == 0)
+            {
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+      png_error(png_ptr, "Invalid attempt to read row data");
+
+   /* Fill the row with IDAT data: */
+   png_ptr->row_buf[0]=255; /* to force error if no data was found */
+   png_read_IDAT_data(png_ptr, png_ptr->row_buf, row_info.rowbytes + 1);
+
+   if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
+   {
+      if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
+         png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
+             png_ptr->prev_row + 1, png_ptr->row_buf[0]);
+      else
+         png_error(png_ptr, "bad adaptive filter value");
+   }
+
+   /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
+    * 1.5.6, while the buffer really is this big in current versions of libpng
+    * it may not be in the future, so this was changed just to copy the
+    * interlaced count:
+    */
+   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
+   {
+      /* Intrapixel differencing */
+      png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
+   }
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+   if (png_ptr->transformations)
+      png_do_read_transformations(png_ptr, &row_info);
+#endif
+
+   /* The transformed pixel depth should match the depth now in row_info. */
+   if (png_ptr->transformed_pixel_depth == 0)
+   {
+      png_ptr->transformed_pixel_depth = row_info.pixel_depth;
+      if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
+         png_error(png_ptr, "sequential row overflow");
+   }
+
+   else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
+      png_error(png_ptr, "internal sequential row size calculation error");
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* Expand interlaced rows to full size */
+   if (png_ptr->interlaced != 0 &&
+      (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      if (png_ptr->pass < 6)
+         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
+             png_ptr->transformations);
+
+      if (dsp_row != NULL)
+         png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+      if (row != NULL)
+         png_combine_row(png_ptr, row, 0/*row*/);
+   }
+
+   else
+#endif
+   {
+      if (row != NULL)
+         png_combine_row(png_ptr, row, -1/*ignored*/);
+
+      if (dsp_row != NULL)
+         png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
+   }
+   png_read_finish_row(png_ptr);
+
+   if (png_ptr->read_row_fn != NULL)
+      (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
+
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read one or more rows of image data.  If the image is interlaced,
+ * and png_set_interlace_handling() has been called, the rows need to
+ * contain the contents of the rows from the previous pass.  If the
+ * image has alpha or transparency, and png_handle_alpha()[*] has been
+ * called, the rows contents must be initialized to the contents of the
+ * screen.
+ *
+ * "row" holds the actual image, and pixels are placed in it
+ * as they arrive.  If the image is displayed after each pass, it will
+ * appear to "sparkle" in.  "display_row" can be used to display a
+ * "chunky" progressive image, with finer detail added as it becomes
+ * available.  If you do not want this "chunky" display, you may pass
+ * NULL for display_row.  If you do not want the sparkle display, and
+ * you have not called png_handle_alpha(), you may pass NULL for rows.
+ * If you have called png_handle_alpha(), and the image has either an
+ * alpha channel or a transparency chunk, you must provide a buffer for
+ * rows.  In this case, you do not have to provide a display_row buffer
+ * also, but you may.  If the image is not interlaced, or if you have
+ * not called png_set_interlace_handling(), the display_row buffer will
+ * be ignored, so pass NULL to it.
+ *
+ * [*] png_handle_alpha() does not exist yet, as of this version of libpng
+ */
+
+void PNGAPI
+png_read_rows(png_structrp png_ptr, png_bytepp row,
+    png_bytepp display_row, png_uint_32 num_rows)
+{
+   png_uint_32 i;
+   png_bytepp rp;
+   png_bytepp dp;
+
+   png_debug(1, "in png_read_rows");
+
+   if (png_ptr == NULL)
+      return;
+
+   rp = row;
+   dp = display_row;
+   if (rp != NULL && dp != NULL)
+      for (i = 0; i < num_rows; i++)
+      {
+         png_bytep rptr = *rp++;
+         png_bytep dptr = *dp++;
+
+         png_read_row(png_ptr, rptr, dptr);
+      }
+
+   else if (rp != NULL)
+      for (i = 0; i < num_rows; i++)
+      {
+         png_bytep rptr = *rp;
+         png_read_row(png_ptr, rptr, NULL);
+         rp++;
+      }
+
+   else if (dp != NULL)
+      for (i = 0; i < num_rows; i++)
+      {
+         png_bytep dptr = *dp;
+         png_read_row(png_ptr, NULL, dptr);
+         dp++;
+      }
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the entire image.  If the image has an alpha channel or a tRNS
+ * chunk, and you have called png_handle_alpha()[*], you will need to
+ * initialize the image to the current image that PNG will be overlaying.
+ * We set the num_rows again here, in case it was incorrectly set in
+ * png_read_start_row() by a call to png_read_update_info() or
+ * png_start_read_image() if png_set_interlace_handling() wasn't called
+ * prior to either of these functions like it should have been.  You can
+ * only call this function once.  If you desire to have an image for
+ * each pass of a interlaced image, use png_read_rows() instead.
+ *
+ * [*] png_handle_alpha() does not exist yet, as of this version of libpng
+ */
+void PNGAPI
+png_read_image(png_structrp png_ptr, png_bytepp image)
+{
+   png_uint_32 i, image_height;
+   int pass, j;
+   png_bytepp rp;
+
+   png_debug(1, "in png_read_image");
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+   {
+      pass = png_set_interlace_handling(png_ptr);
+      /* And make sure transforms are initialized. */
+      png_start_read_image(png_ptr);
+   }
+   else
+   {
+      if (png_ptr->interlaced != 0 &&
+          (png_ptr->transformations & PNG_INTERLACE) == 0)
+      {
+         /* Caller called png_start_read_image or png_read_update_info without
+          * first turning on the PNG_INTERLACE transform.  We can fix this here,
+          * but the caller should do it!
+          */
+         png_warning(png_ptr, "Interlace handling should be turned on when "
+             "using png_read_image");
+         /* Make sure this is set correctly */
+         png_ptr->num_rows = png_ptr->height;
+      }
+
+      /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
+       * the above error case.
+       */
+      pass = png_set_interlace_handling(png_ptr);
+   }
+#else
+   if (png_ptr->interlaced)
+      png_error(png_ptr,
+          "Cannot read interlaced image -- interlace handler disabled");
+
+   pass = 1;
+#endif
+
+   image_height=png_ptr->height;
+
+   for (j = 0; j < pass; j++)
+   {
+      rp = image;
+      for (i = 0; i < image_height; i++)
+      {
+         png_read_row(png_ptr, *rp, NULL);
+         rp++;
+      }
+   }
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the end of the PNG file.  Will not read past the end of the
+ * file, will verify the end is accurate, and will read any comments
+ * or time information at the end of the file, if info is not NULL.
+ */
+void PNGAPI
+png_read_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   int keep;
+#endif
+
+   png_debug(1, "in png_read_end");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* If png_read_end is called in the middle of reading the rows there may
+    * still be pending IDAT data and an owned zstream.  Deal with this here.
+    */
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   if (png_chunk_unknown_handling(png_ptr, png_IDAT) == 0)
+#endif
+      png_read_finish_IDAT(png_ptr);
+
+#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   /* Report invalid palette index; added at libng-1.5.10 */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+       png_ptr->num_palette_max > png_ptr->num_palette)
+      png_benign_error(png_ptr, "Read palette index exceeding num_palette");
+#endif
+
+   do
+   {
+      png_uint_32 length = png_read_chunk_header(png_ptr);
+      png_uint_32 chunk_name = png_ptr->chunk_name;
+
+      if (chunk_name != png_IDAT)
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+
+      if (chunk_name == png_IEND)
+         png_handle_IEND(png_ptr, info_ptr, length);
+
+      else if (chunk_name == png_IHDR)
+         png_handle_IHDR(png_ptr, info_ptr, length);
+
+      else if (info_ptr == NULL)
+         png_crc_finish(png_ptr, length);
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+      {
+         if (chunk_name == png_IDAT)
+         {
+            if ((length > 0 && !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
+                || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
+               png_benign_error(png_ptr, ".Too many IDATs found");
+         }
+         png_handle_unknown(png_ptr, info_ptr, length, keep);
+         if (chunk_name == png_PLTE)
+            png_ptr->mode |= PNG_HAVE_PLTE;
+      }
+#endif
+
+      else if (chunk_name == png_IDAT)
+      {
+         /* Zero length IDATs are legal after the last IDAT has been
+          * read, but not after other chunks have been read.  1.6 does not
+          * always read all the deflate data; specifically it cannot be relied
+          * upon to read the Adler32 at the end.  If it doesn't ignore IDAT
+          * chunks which are longer than zero as well:
+          */
+         if ((length > 0 && !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
+             || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
+            png_benign_error(png_ptr, "..Too many IDATs found");
+
+         png_crc_finish(png_ptr, length);
+      }
+      else if (chunk_name == png_PLTE)
+         png_handle_PLTE(png_ptr, info_ptr, length);
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+      else if (chunk_name == png_bKGD)
+         png_handle_bKGD(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+      else if (chunk_name == png_cHRM)
+         png_handle_cHRM(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_eXIf_SUPPORTED
+      else if (chunk_name == png_eXIf)
+         png_handle_eXIf(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+      else if (chunk_name == png_gAMA)
+         png_handle_gAMA(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+      else if (chunk_name == png_hIST)
+         png_handle_hIST(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+      else if (chunk_name == png_oFFs)
+         png_handle_oFFs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+      else if (chunk_name == png_pCAL)
+         png_handle_pCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+      else if (chunk_name == png_sCAL)
+         png_handle_sCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+      else if (chunk_name == png_pHYs)
+         png_handle_pHYs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+      else if (chunk_name == png_sBIT)
+         png_handle_sBIT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+      else if (chunk_name == png_sRGB)
+         png_handle_sRGB(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+      else if (chunk_name == png_iCCP)
+         png_handle_iCCP(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+      else if (chunk_name == png_sPLT)
+         png_handle_sPLT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+      else if (chunk_name == png_tEXt)
+         png_handle_tEXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+      else if (chunk_name == png_tIME)
+         png_handle_tIME(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+      else if (chunk_name == png_tRNS)
+         png_handle_tRNS(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+      else if (chunk_name == png_zTXt)
+         png_handle_zTXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+      else if (chunk_name == png_iTXt)
+         png_handle_iTXt(png_ptr, info_ptr, length);
+#endif
+
+      else
+         png_handle_unknown(png_ptr, info_ptr, length,
+             PNG_HANDLE_CHUNK_AS_DEFAULT);
+   } while ((png_ptr->mode & PNG_HAVE_IEND) == 0);
+}
+#endif /* SEQUENTIAL_READ */
+
+/* Free all memory used in the read struct */
+static void
+png_read_destroy(png_structrp png_ptr)
+{
+   png_debug(1, "in png_read_destroy");
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   png_destroy_gamma_table(png_ptr);
+#endif
+
+   png_free(png_ptr, png_ptr->big_row_buf);
+   png_ptr->big_row_buf = NULL;
+   png_free(png_ptr, png_ptr->big_prev_row);
+   png_ptr->big_prev_row = NULL;
+   png_free(png_ptr, png_ptr->read_buffer);
+   png_ptr->read_buffer = NULL;
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   png_free(png_ptr, png_ptr->palette_lookup);
+   png_ptr->palette_lookup = NULL;
+   png_free(png_ptr, png_ptr->quantize_index);
+   png_ptr->quantize_index = NULL;
+#endif
+
+   if ((png_ptr->free_me & PNG_FREE_PLTE) != 0)
+   {
+      png_zfree(png_ptr, png_ptr->palette);
+      png_ptr->palette = NULL;
+   }
+   png_ptr->free_me &= ~PNG_FREE_PLTE;
+
+#if defined(PNG_tRNS_SUPPORTED) || \
+    defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if ((png_ptr->free_me & PNG_FREE_TRNS) != 0)
+   {
+      png_free(png_ptr, png_ptr->trans_alpha);
+      png_ptr->trans_alpha = NULL;
+   }
+   png_ptr->free_me &= ~PNG_FREE_TRNS;
+#endif
+
+   inflateEnd(&png_ptr->zstream);
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+   png_free(png_ptr, png_ptr->save_buffer);
+   png_ptr->save_buffer = NULL;
+#endif
+
+#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) && \
+   defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+   png_free(png_ptr, png_ptr->unknown_chunk.data);
+   png_ptr->unknown_chunk.data = NULL;
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   png_free(png_ptr, png_ptr->chunk_list);
+   png_ptr->chunk_list = NULL;
+#endif
+
+#if defined(PNG_READ_EXPAND_SUPPORTED) && \
+    defined(PNG_ARM_NEON_IMPLEMENTATION)
+   png_free(png_ptr, png_ptr->riffled_palette);
+   png_ptr->riffled_palette = NULL;
+#endif
+
+   /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error
+    * callbacks are still set at this point.  They are required to complete the
+    * destruction of the png_struct itself.
+    */
+}
+
+/* Free all memory used by the read */
+void PNGAPI
+png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
+    png_infopp end_info_ptr_ptr)
+{
+   png_structrp png_ptr = NULL;
+
+   png_debug(1, "in png_destroy_read_struct");
+
+   if (png_ptr_ptr != NULL)
+      png_ptr = *png_ptr_ptr;
+
+   if (png_ptr == NULL)
+      return;
+
+   /* libpng 1.6.0: use the API to destroy info structs to ensure consistent
+    * behavior.  Prior to 1.6.0 libpng did extra 'info' destruction in this API.
+    * The extra was, apparently, unnecessary yet this hides memory leak bugs.
+    */
+   png_destroy_info_struct(png_ptr, end_info_ptr_ptr);
+   png_destroy_info_struct(png_ptr, info_ptr_ptr);
+
+   *png_ptr_ptr = NULL;
+   png_read_destroy(png_ptr);
+   png_destroy_png_struct(png_ptr);
+}
+
+void PNGAPI
+png_set_read_status_fn(png_structrp png_ptr, png_read_status_ptr read_row_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->read_row_fn = read_row_fn;
+}
+
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+void PNGAPI
+png_read_png(png_structrp png_ptr, png_inforp info_ptr,
+    int transforms, voidp params)
+{
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* png_read_info() gives us all of the information from the
+    * PNG file before the first IDAT (image data chunk).
+    */
+   png_read_info(png_ptr, info_ptr);
+   if (info_ptr->height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
+      png_error(png_ptr, "Image is too high to process with png_read_png()");
+
+   /* -------------- image transformations start here ------------------- */
+   /* libpng 1.6.10: add code to cause a png_app_error if a selected TRANSFORM
+    * is not implemented.  This will only happen in de-configured (non-default)
+    * libpng builds.  The results can be unexpected - png_read_png may return
+    * short or mal-formed rows because the transform is skipped.
+    */
+
+   /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
+    */
+   if ((transforms & PNG_TRANSFORM_SCALE_16) != 0)
+      /* Added at libpng-1.5.4. "strip_16" produces the same result that it
+       * did in earlier versions, while "scale_16" is now more accurate.
+       */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+      png_set_scale_16(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SCALE_16 not supported");
+#endif
+
+   /* If both SCALE and STRIP are required pngrtran will effectively cancel the
+    * latter by doing SCALE first.  This is ok and allows apps not to check for
+    * which is supported to get the right answer.
+    */
+   if ((transforms & PNG_TRANSFORM_STRIP_16) != 0)
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+      png_set_strip_16(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_16 not supported");
+#endif
+
+   /* Strip alpha bytes from the input data without combining with
+    * the background (not recommended).
+    */
+   if ((transforms & PNG_TRANSFORM_STRIP_ALPHA) != 0)
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+      png_set_strip_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_ALPHA not supported");
+#endif
+
+   /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
+    * byte into separate bytes (useful for paletted and grayscale images).
+    */
+   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
+#ifdef PNG_READ_PACK_SUPPORTED
+      png_set_packing(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
+#endif
+
+   /* Change the order of packed pixels to least significant bit first
+    * (not useful if you are using png_set_packing).
+    */
+   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+      png_set_packswap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
+#endif
+
+   /* Expand paletted colors into true RGB triplets
+    * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
+    * Expand paletted or RGB images with transparency to full alpha
+    * channels so the data will be available as RGBA quartets.
+    */
+   if ((transforms & PNG_TRANSFORM_EXPAND) != 0)
+#ifdef PNG_READ_EXPAND_SUPPORTED
+      png_set_expand(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND not supported");
+#endif
+
+   /* We don't handle background color or gamma transformation or quantizing.
+    */
+
+   /* Invert monochrome files to have 0 as white and 1 as black
+    */
+   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
+#ifdef PNG_READ_INVERT_SUPPORTED
+      png_set_invert_mono(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
+#endif
+
+   /* If you want to shift the pixel values from the range [0,255] or
+    * [0,65535] to the original [0,7] or [0,31], or whatever range the
+    * colors were originally in:
+    */
+   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
+#ifdef PNG_READ_SHIFT_SUPPORTED
+      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+         png_set_shift(png_ptr, &info_ptr->sig_bit);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
+#endif
+
+   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
+   if ((transforms & PNG_TRANSFORM_BGR) != 0)
+#ifdef PNG_READ_BGR_SUPPORTED
+      png_set_bgr(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
+#endif
+
+   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
+   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+      png_set_swap_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
+#endif
+
+   /* Swap bytes of 16-bit files to least significant byte first */
+   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
+#ifdef PNG_READ_SWAP_SUPPORTED
+      png_set_swap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
+#endif
+
+/* Added at libpng-1.2.41 */
+   /* Invert the alpha channel from opacity to transparency */
+   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+      png_set_invert_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
+#endif
+
+/* Added at libpng-1.2.41 */
+   /* Expand grayscale image to RGB */
+   if ((transforms & PNG_TRANSFORM_GRAY_TO_RGB) != 0)
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+      png_set_gray_to_rgb(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_GRAY_TO_RGB not supported");
+#endif
+
+/* Added at libpng-1.5.4 */
+   if ((transforms & PNG_TRANSFORM_EXPAND_16) != 0)
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+      png_set_expand_16(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND_16 not supported");
+#endif
+
+   /* We don't handle adding filler bytes */
+
+   /* We use png_read_image and rely on that for interlace handling, but we also
+    * call png_read_update_info therefore must turn on interlace handling now:
+    */
+   (void)png_set_interlace_handling(png_ptr);
+
+   /* Optional call to gamma correct and add the background to the palette
+    * and update info structure.  REQUIRED if you are expecting libpng to
+    * update the palette for you (i.e., you selected such a transform above).
+    */
+   png_read_update_info(png_ptr, info_ptr);
+
+   /* -------------- image transformations end here ------------------- */
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
+   if (info_ptr->row_pointers == NULL)
+   {
+      png_uint_32 iptr;
+
+      info_ptr->row_pointers = png_voidcast(png_bytepp, png_malloc(png_ptr,
+          info_ptr->height * (sizeof (png_bytep))));
+
+      for (iptr=0; iptr<info_ptr->height; iptr++)
+         info_ptr->row_pointers[iptr] = NULL;
+
+      info_ptr->free_me |= PNG_FREE_ROWS;
+
+      for (iptr = 0; iptr < info_ptr->height; iptr++)
+         info_ptr->row_pointers[iptr] = png_voidcast(png_bytep,
+             png_malloc(png_ptr, info_ptr->rowbytes));
+   }
+
+   png_read_image(png_ptr, info_ptr->row_pointers);
+   info_ptr->valid |= PNG_INFO_IDAT;
+
+   /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
+   png_read_end(png_ptr, info_ptr);
+
+   PNG_UNUSED(params)
+}
+#endif /* INFO_IMAGE */
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+/* SIMPLIFIED READ
+ *
+ * This code currently relies on the sequential reader, though it could easily
+ * be made to work with the progressive one.
+ */
+/* Arguments to png_image_finish_read: */
+
+/* Encoding of PNG data (used by the color-map code) */
+#  define P_NOTSET  0 /* File encoding not yet known */
+#  define P_sRGB    1 /* 8-bit encoded to sRGB gamma */
+#  define P_LINEAR  2 /* 16-bit linear: not encoded, NOT pre-multiplied! */
+#  define P_FILE    3 /* 8-bit encoded to file gamma, not sRGB or linear */
+#  define P_LINEAR8 4 /* 8-bit linear: only from a file value */
+
+/* Color-map processing: after libpng has run on the PNG image further
+ * processing may be needed to convert the data to color-map indices.
+ */
+#define PNG_CMAP_NONE      0
+#define PNG_CMAP_GA        1 /* Process GA data to a color-map with alpha */
+#define PNG_CMAP_TRANS     2 /* Process GA data to a background index */
+#define PNG_CMAP_RGB       3 /* Process RGB data */
+#define PNG_CMAP_RGB_ALPHA 4 /* Process RGBA data */
+
+/* The following document where the background is for each processing case. */
+#define PNG_CMAP_NONE_BACKGROUND      256
+#define PNG_CMAP_GA_BACKGROUND        231
+#define PNG_CMAP_TRANS_BACKGROUND     254
+#define PNG_CMAP_RGB_BACKGROUND       256
+#define PNG_CMAP_RGB_ALPHA_BACKGROUND 216
+
+typedef struct
+{
+   /* Arguments: */
+   png_imagep image;
+   png_voidp  buffer;
+   png_int_32 row_stride;
+   png_voidp  colormap;
+   png_const_colorp background;
+   /* Local variables: */
+   png_voidp       local_row;
+   png_voidp       first_row;
+   ptrdiff_t       row_bytes;           /* step between rows */
+   int             file_encoding;       /* E_ values above */
+   png_fixed_point gamma_to_linear;     /* For P_FILE, reciprocal of gamma */
+   int             colormap_processing; /* PNG_CMAP_ values above */
+} png_image_read_control;
+
+/* Do all the *safe* initialization - 'safe' means that png_error won't be
+ * called, so setting up the jmp_buf is not required.  This means that anything
+ * called from here must *not* call png_malloc - it has to call png_malloc_warn
+ * instead so that control is returned safely back to this routine.
+ */
+static int
+png_image_read_init(png_imagep image)
+{
+   if (image->opaque == NULL)
+   {
+      png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image,
+          png_safe_error, png_safe_warning);
+
+      /* And set the rest of the structure to NULL to ensure that the various
+       * fields are consistent.
+       */
+      memset(image, 0, (sizeof *image));
+      image->version = PNG_IMAGE_VERSION;
+
+      if (png_ptr != NULL)
+      {
+         png_infop info_ptr = png_create_info_struct(png_ptr);
+
+         if (info_ptr != NULL)
+         {
+            png_controlp control = png_voidcast(png_controlp,
+                png_malloc_warn(png_ptr, (sizeof *control)));
+
+            if (control != NULL)
+            {
+               memset(control, 0, (sizeof *control));
+
+               control->png_ptr = png_ptr;
+               control->info_ptr = info_ptr;
+               control->for_write = 0;
+
+               image->opaque = control;
+               return 1;
+            }
+
+            /* Error clean up */
+            png_destroy_info_struct(png_ptr, &info_ptr);
+         }
+
+         png_destroy_read_struct(&png_ptr, NULL, NULL);
+      }
+
+      return png_image_error(image, "png_image_read: out of memory");
+   }
+
+   return png_image_error(image, "png_image_read: opaque pointer not NULL");
+}
+
+/* Utility to find the base format of a PNG file from a png_struct. */
+static png_uint_32
+png_image_format(png_structrp png_ptr)
+{
+   png_uint_32 format = 0;
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      format |= PNG_FORMAT_FLAG_COLOR;
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      format |= PNG_FORMAT_FLAG_ALPHA;
+
+   /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
+    * sets the png_struct fields; that's all we are interested in here.  The
+    * precise interaction with an app call to png_set_tRNS and PNG file reading
+    * is unclear.
+    */
+   else if (png_ptr->num_trans > 0)
+      format |= PNG_FORMAT_FLAG_ALPHA;
+
+   if (png_ptr->bit_depth == 16)
+      format |= PNG_FORMAT_FLAG_LINEAR;
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) != 0)
+      format |= PNG_FORMAT_FLAG_COLORMAP;
+
+   return format;
+}
+
+/* Is the given gamma significantly different from sRGB?  The test is the same
+ * one used in pngrtran.c when deciding whether to do gamma correction.  The
+ * arithmetic optimizes the division by using the fact that the inverse of the
+ * file sRGB gamma is 2.2
+ */
+static int
+png_gamma_not_sRGB(png_fixed_point g)
+{
+   if (g < PNG_FP_1)
+   {
+      /* An uninitialized gamma is assumed to be sRGB for the simplified API. */
+      if (g == 0)
+         return 0;
+
+      return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */);
+   }
+
+   return 1;
+}
+
+/* Do the main body of a 'png_image_begin_read' function; read the PNG file
+ * header and fill in all the information.  This is executed in a safe context,
+ * unlike the init routine above.
+ */
+static int
+png_image_read_header(png_voidp argument)
+{
+   png_imagep image = png_voidcast(png_imagep, argument);
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_inforp info_ptr = image->opaque->info_ptr;
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+   png_set_benign_errors(png_ptr, 1/*warn*/);
+#endif
+   png_read_info(png_ptr, info_ptr);
+
+   /* Do this the fast way; just read directly out of png_struct. */
+   image->width = png_ptr->width;
+   image->height = png_ptr->height;
+
+   {
+      png_uint_32 format = png_image_format(png_ptr);
+
+      image->format = format;
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+      /* Does the colorspace match sRGB?  If there is no color endpoint
+       * (colorant) information assume yes, otherwise require the
+       * 'ENDPOINTS_MATCHP_sRGB' colorspace flag to have been set.  If the
+       * colorspace has been determined to be invalid ignore it.
+       */
+      if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags
+         & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB|
+            PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS))
+         image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB;
+#endif
+   }
+
+   /* We need the maximum number of entries regardless of the format the
+    * application sets here.
+    */
+   {
+      png_uint_32 cmap_entries;
+
+      switch (png_ptr->color_type)
+      {
+         case PNG_COLOR_TYPE_GRAY:
+            cmap_entries = 1U << png_ptr->bit_depth;
+            break;
+
+         case PNG_COLOR_TYPE_PALETTE:
+            cmap_entries = (png_uint_32)png_ptr->num_palette;
+            break;
+
+         default:
+            cmap_entries = 256;
+            break;
+      }
+
+      if (cmap_entries > 256)
+         cmap_entries = 256;
+
+      image->colormap_entries = cmap_entries;
+   }
+
+   return 1;
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+int PNGAPI
+png_image_begin_read_from_stdio(png_imagep image, FILE* file)
+{
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (file != NULL)
+      {
+         if (png_image_read_init(image) != 0)
+         {
+            /* This is slightly evil, but png_init_io doesn't do anything other
+             * than this and we haven't changed the standard IO functions so
+             * this saves a 'safe' function.
+             */
+            image->opaque->png_ptr->io_ptr = file;
+            return png_safe_execute(image, png_image_read_header, image);
+         }
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_begin_read_from_stdio: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_begin_read_from_stdio: incorrect PNG_IMAGE_VERSION");
+
+   return 0;
+}
+
+int PNGAPI
+png_image_begin_read_from_file(png_imagep image, const char *file_name)
+{
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (file_name != NULL)
+      {
+         FILE *fp = fopen(file_name, "rb");
+
+         if (fp != NULL)
+         {
+            if (png_image_read_init(image) != 0)
+            {
+               image->opaque->png_ptr->io_ptr = fp;
+               image->opaque->owned_file = 1;
+               return png_safe_execute(image, png_image_read_header, image);
+            }
+
+            /* Clean up: just the opened file. */
+            (void)fclose(fp);
+         }
+
+         else
+            return png_image_error(image, strerror(errno));
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_begin_read_from_file: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_begin_read_from_file: incorrect PNG_IMAGE_VERSION");
+
+   return 0;
+}
+#endif /* STDIO */
+
+static void PNGCBAPI
+png_image_memory_read(png_structp png_ptr, png_bytep out, size_t need)
+{
+   if (png_ptr != NULL)
+   {
+      png_imagep image = png_voidcast(png_imagep, png_ptr->io_ptr);
+      if (image != NULL)
+      {
+         png_controlp cp = image->opaque;
+         if (cp != NULL)
+         {
+            png_const_bytep memory = cp->memory;
+            size_t size = cp->size;
+
+            if (memory != NULL && size >= need)
+            {
+               memcpy(out, memory, need);
+               cp->memory = memory + need;
+               cp->size = size - need;
+               return;
+            }
+
+            png_error(png_ptr, "read beyond end of data");
+         }
+      }
+
+      png_error(png_ptr, "invalid memory read");
+   }
+}
+
+int PNGAPI png_image_begin_read_from_memory(png_imagep image,
+    png_const_voidp memory, size_t size)
+{
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (memory != NULL && size > 0)
+      {
+         if (png_image_read_init(image) != 0)
+         {
+            /* Now set the IO functions to read from the memory buffer and
+             * store it into io_ptr.  Again do this in-place to avoid calling a
+             * libpng function that requires error handling.
+             */
+            image->opaque->memory = png_voidcast(png_const_bytep, memory);
+            image->opaque->size = size;
+            image->opaque->png_ptr->io_ptr = image;
+            image->opaque->png_ptr->read_data_fn = png_image_memory_read;
+
+            return png_safe_execute(image, png_image_read_header, image);
+         }
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_begin_read_from_memory: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_begin_read_from_memory: incorrect PNG_IMAGE_VERSION");
+
+   return 0;
+}
+
+/* Utility function to skip chunks that are not used by the simplified image
+ * read functions and an appropriate macro to call it.
+ */
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+static void
+png_image_skip_unused_chunks(png_structrp png_ptr)
+{
+   /* Prepare the reader to ignore all recognized chunks whose data will not
+    * be used, i.e., all chunks recognized by libpng except for those
+    * involved in basic image reading:
+    *
+    *    IHDR, PLTE, IDAT, IEND
+    *
+    * Or image data handling:
+    *
+    *    tRNS, bKGD, gAMA, cHRM, sRGB, [iCCP] and sBIT.
+    *
+    * This provides a small performance improvement and eliminates any
+    * potential vulnerability to security problems in the unused chunks.
+    *
+    * At present the iCCP chunk data isn't used, so iCCP chunk can be ignored
+    * too.  This allows the simplified API to be compiled without iCCP support,
+    * however if the support is there the chunk is still checked to detect
+    * errors (which are unfortunately quite common.)
+    */
+   {
+         static const png_byte chunks_to_process[] = {
+            98,  75,  71,  68, '\0',  /* bKGD */
+            99,  72,  82,  77, '\0',  /* cHRM */
+           103,  65,  77,  65, '\0',  /* gAMA */
+#        ifdef PNG_READ_iCCP_SUPPORTED
+           105,  67,  67,  80, '\0',  /* iCCP */
+#        endif
+           115,  66,  73,  84, '\0',  /* sBIT */
+           115,  82,  71,  66, '\0',  /* sRGB */
+           };
+
+       /* Ignore unknown chunks and all other chunks except for the
+        * IHDR, PLTE, tRNS, IDAT, and IEND chunks.
+        */
+       png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER,
+           NULL, -1);
+
+       /* But do not ignore image data handling chunks */
+       png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT,
+           chunks_to_process, (int)/*SAFE*/(sizeof chunks_to_process)/5);
+   }
+}
+
+#  define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p)
+#else
+#  define PNG_SKIP_CHUNKS(p) ((void)0)
+#endif /* HANDLE_AS_UNKNOWN */
+
+/* The following macro gives the exact rounded answer for all values in the
+ * range 0..255 (it actually divides by 51.2, but the rounding still generates
+ * the correct numbers 0..5
+ */
+#define PNG_DIV51(v8) (((v8) * 5 + 130) >> 8)
+
+/* Utility functions to make particular color-maps */
+static void
+set_file_encoding(png_image_read_control *display)
+{
+   png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
+   if (png_gamma_significant(g) != 0)
+   {
+      if (png_gamma_not_sRGB(g) != 0)
+      {
+         display->file_encoding = P_FILE;
+         display->gamma_to_linear = png_reciprocal(g);
+      }
+
+      else
+         display->file_encoding = P_sRGB;
+   }
+
+   else
+      display->file_encoding = P_LINEAR8;
+}
+
+static unsigned int
+decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding)
+{
+   if (encoding == P_FILE) /* double check */
+      encoding = display->file_encoding;
+
+   if (encoding == P_NOTSET) /* must be the file encoding */
+   {
+      set_file_encoding(display);
+      encoding = display->file_encoding;
+   }
+
+   switch (encoding)
+   {
+      case P_FILE:
+         value = png_gamma_16bit_correct(value*257, display->gamma_to_linear);
+         break;
+
+      case P_sRGB:
+         value = png_sRGB_table[value];
+         break;
+
+      case P_LINEAR:
+         break;
+
+      case P_LINEAR8:
+         value *= 257;
+         break;
+
+#ifdef __GNUC__
+      default:
+         png_error(display->image->opaque->png_ptr,
+             "unexpected encoding (internal error)");
+#endif
+   }
+
+   return value;
+}
+
+static png_uint_32
+png_colormap_compose(png_image_read_control *display,
+    png_uint_32 foreground, int foreground_encoding, png_uint_32 alpha,
+    png_uint_32 background, int encoding)
+{
+   /* The file value is composed on the background, the background has the given
+    * encoding and so does the result, the file is encoded with P_FILE and the
+    * file and alpha are 8-bit values.  The (output) encoding will always be
+    * P_LINEAR or P_sRGB.
+    */
+   png_uint_32 f = decode_gamma(display, foreground, foreground_encoding);
+   png_uint_32 b = decode_gamma(display, background, encoding);
+
+   /* The alpha is always an 8-bit value (it comes from the palette), the value
+    * scaled by 255 is what PNG_sRGB_FROM_LINEAR requires.
+    */
+   f = f * alpha + b * (255-alpha);
+
+   if (encoding == P_LINEAR)
+   {
+      /* Scale to 65535; divide by 255, approximately (in fact this is extremely
+       * accurate, it divides by 255.00000005937181414556, with no overflow.)
+       */
+      f *= 257; /* Now scaled by 65535 */
+      f += f >> 16;
+      f = (f+32768) >> 16;
+   }
+
+   else /* P_sRGB */
+      f = PNG_sRGB_FROM_LINEAR(f);
+
+   return f;
+}
+
+/* NOTE: P_LINEAR values to this routine must be 16-bit, but P_FILE values must
+ * be 8-bit.
+ */
+static void
+png_create_colormap_entry(png_image_read_control *display,
+    png_uint_32 ip, png_uint_32 red, png_uint_32 green, png_uint_32 blue,
+    png_uint_32 alpha, int encoding)
+{
+   png_imagep image = display->image;
+   int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
+       P_LINEAR : P_sRGB;
+   int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
+       (red != green || green != blue);
+
+   if (ip > 255)
+      png_error(image->opaque->png_ptr, "color-map index out of range");
+
+   /* Update the cache with whether the file gamma is significantly different
+    * from sRGB.
+    */
+   if (encoding == P_FILE)
+   {
+      if (display->file_encoding == P_NOTSET)
+         set_file_encoding(display);
+
+      /* Note that the cached value may be P_FILE too, but if it is then the
+       * gamma_to_linear member has been set.
+       */
+      encoding = display->file_encoding;
+   }
+
+   if (encoding == P_FILE)
+   {
+      png_fixed_point g = display->gamma_to_linear;
+
+      red = png_gamma_16bit_correct(red*257, g);
+      green = png_gamma_16bit_correct(green*257, g);
+      blue = png_gamma_16bit_correct(blue*257, g);
+
+      if (convert_to_Y != 0 || output_encoding == P_LINEAR)
+      {
+         alpha *= 257;
+         encoding = P_LINEAR;
+      }
+
+      else
+      {
+         red = PNG_sRGB_FROM_LINEAR(red * 255);
+         green = PNG_sRGB_FROM_LINEAR(green * 255);
+         blue = PNG_sRGB_FROM_LINEAR(blue * 255);
+         encoding = P_sRGB;
+      }
+   }
+
+   else if (encoding == P_LINEAR8)
+   {
+      /* This encoding occurs quite frequently in test cases because PngSuite
+       * includes a gAMA 1.0 chunk with most images.
+       */
+      red *= 257;
+      green *= 257;
+      blue *= 257;
+      alpha *= 257;
+      encoding = P_LINEAR;
+   }
+
+   else if (encoding == P_sRGB &&
+       (convert_to_Y  != 0 || output_encoding == P_LINEAR))
+   {
+      /* The values are 8-bit sRGB values, but must be converted to 16-bit
+       * linear.
+       */
+      red = png_sRGB_table[red];
+      green = png_sRGB_table[green];
+      blue = png_sRGB_table[blue];
+      alpha *= 257;
+      encoding = P_LINEAR;
+   }
+
+   /* This is set if the color isn't gray but the output is. */
+   if (encoding == P_LINEAR)
+   {
+      if (convert_to_Y != 0)
+      {
+         /* NOTE: these values are copied from png_do_rgb_to_gray */
+         png_uint_32 y = (png_uint_32)6968 * red  + (png_uint_32)23434 * green +
+            (png_uint_32)2366 * blue;
+
+         if (output_encoding == P_LINEAR)
+            y = (y + 16384) >> 15;
+
+         else
+         {
+            /* y is scaled by 32768, we need it scaled by 255: */
+            y = (y + 128) >> 8;
+            y *= 255;
+            y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
+            alpha = PNG_DIV257(alpha);
+            encoding = P_sRGB;
+         }
+
+         blue = red = green = y;
+      }
+
+      else if (output_encoding == P_sRGB)
+      {
+         red = PNG_sRGB_FROM_LINEAR(red * 255);
+         green = PNG_sRGB_FROM_LINEAR(green * 255);
+         blue = PNG_sRGB_FROM_LINEAR(blue * 255);
+         alpha = PNG_DIV257(alpha);
+         encoding = P_sRGB;
+      }
+   }
+
+   if (encoding != output_encoding)
+      png_error(image->opaque->png_ptr, "bad encoding (internal error)");
+
+   /* Store the value. */
+   {
+#     ifdef PNG_FORMAT_AFIRST_SUPPORTED
+         int afirst = (image->format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
+            (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
+#     else
+#        define afirst 0
+#     endif
+#     ifdef PNG_FORMAT_BGR_SUPPORTED
+         int bgr = (image->format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
+#     else
+#        define bgr 0
+#     endif
+
+      if (output_encoding == P_LINEAR)
+      {
+         png_uint_16p entry = png_voidcast(png_uint_16p, display->colormap);
+
+         entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
+
+         /* The linear 16-bit values must be pre-multiplied by the alpha channel
+          * value, if less than 65535 (this is, effectively, composite on black
+          * if the alpha channel is removed.)
+          */
+         switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
+         {
+            case 4:
+               entry[afirst ? 0 : 3] = (png_uint_16)alpha;
+               /* FALLTHROUGH */
+
+            case 3:
+               if (alpha < 65535)
+               {
+                  if (alpha > 0)
+                  {
+                     blue = (blue * alpha + 32767U)/65535U;
+                     green = (green * alpha + 32767U)/65535U;
+                     red = (red * alpha + 32767U)/65535U;
+                  }
+
+                  else
+                     red = green = blue = 0;
+               }
+               entry[afirst + (2 ^ bgr)] = (png_uint_16)blue;
+               entry[afirst + 1] = (png_uint_16)green;
+               entry[afirst + bgr] = (png_uint_16)red;
+               break;
+
+            case 2:
+               entry[1 ^ afirst] = (png_uint_16)alpha;
+               /* FALLTHROUGH */
+
+            case 1:
+               if (alpha < 65535)
+               {
+                  if (alpha > 0)
+                     green = (green * alpha + 32767U)/65535U;
+
+                  else
+                     green = 0;
+               }
+               entry[afirst] = (png_uint_16)green;
+               break;
+
+            default:
+               break;
+         }
+      }
+
+      else /* output encoding is P_sRGB */
+      {
+         png_bytep entry = png_voidcast(png_bytep, display->colormap);
+
+         entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
+
+         switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
+         {
+            case 4:
+               entry[afirst ? 0 : 3] = (png_byte)alpha;
+               /* FALLTHROUGH */
+            case 3:
+               entry[afirst + (2 ^ bgr)] = (png_byte)blue;
+               entry[afirst + 1] = (png_byte)green;
+               entry[afirst + bgr] = (png_byte)red;
+               break;
+
+            case 2:
+               entry[1 ^ afirst] = (png_byte)alpha;
+               /* FALLTHROUGH */
+            case 1:
+               entry[afirst] = (png_byte)green;
+               break;
+
+            default:
+               break;
+         }
+      }
+
+#     ifdef afirst
+#        undef afirst
+#     endif
+#     ifdef bgr
+#        undef bgr
+#     endif
+   }
+}
+
+static int
+make_gray_file_colormap(png_image_read_control *display)
+{
+   unsigned int i;
+
+   for (i=0; i<256; ++i)
+      png_create_colormap_entry(display, i, i, i, i, 255, P_FILE);
+
+   return (int)i;
+}
+
+static int
+make_gray_colormap(png_image_read_control *display)
+{
+   unsigned int i;
+
+   for (i=0; i<256; ++i)
+      png_create_colormap_entry(display, i, i, i, i, 255, P_sRGB);
+
+   return (int)i;
+}
+#define PNG_GRAY_COLORMAP_ENTRIES 256
+
+static int
+make_ga_colormap(png_image_read_control *display)
+{
+   unsigned int i, a;
+
+   /* Alpha is retained, the output will be a color-map with entries
+    * selected by six levels of alpha.  One transparent entry, 6 gray
+    * levels for all the intermediate alpha values, leaving 230 entries
+    * for the opaque grays.  The color-map entries are the six values
+    * [0..5]*51, the GA processing uses PNG_DIV51(value) to find the
+    * relevant entry.
+    *
+    * if (alpha > 229) // opaque
+    * {
+    *    // The 231 entries are selected to make the math below work:
+    *    base = 0;
+    *    entry = (231 * gray + 128) >> 8;
+    * }
+    * else if (alpha < 26) // transparent
+    * {
+    *    base = 231;
+    *    entry = 0;
+    * }
+    * else // partially opaque
+    * {
+    *    base = 226 + 6 * PNG_DIV51(alpha);
+    *    entry = PNG_DIV51(gray);
+    * }
+    */
+   i = 0;
+   while (i < 231)
+   {
+      unsigned int gray = (i * 256 + 115) / 231;
+      png_create_colormap_entry(display, i++, gray, gray, gray, 255, P_sRGB);
+   }
+
+   /* 255 is used here for the component values for consistency with the code
+    * that undoes premultiplication in pngwrite.c.
+    */
+   png_create_colormap_entry(display, i++, 255, 255, 255, 0, P_sRGB);
+
+   for (a=1; a<5; ++a)
+   {
+      unsigned int g;
+
+      for (g=0; g<6; ++g)
+         png_create_colormap_entry(display, i++, g*51, g*51, g*51, a*51,
+             P_sRGB);
+   }
+
+   return (int)i;
+}
+
+#define PNG_GA_COLORMAP_ENTRIES 256
+
+static int
+make_rgb_colormap(png_image_read_control *display)
+{
+   unsigned int i, r;
+
+   /* Build a 6x6x6 opaque RGB cube */
+   for (i=r=0; r<6; ++r)
+   {
+      unsigned int g;
+
+      for (g=0; g<6; ++g)
+      {
+         unsigned int b;
+
+         for (b=0; b<6; ++b)
+            png_create_colormap_entry(display, i++, r*51, g*51, b*51, 255,
+                P_sRGB);
+      }
+   }
+
+   return (int)i;
+}
+
+#define PNG_RGB_COLORMAP_ENTRIES 216
+
+/* Return a palette index to the above palette given three 8-bit sRGB values. */
+#define PNG_RGB_INDEX(r,g,b) \
+   ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b)))
+
+static int
+png_image_read_colormap(png_voidp argument)
+{
+   png_image_read_control *display =
+      png_voidcast(png_image_read_control*, argument);
+   png_imagep image = display->image;
+
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_uint_32 output_format = image->format;
+   int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
+      P_LINEAR : P_sRGB;
+
+   unsigned int cmap_entries;
+   unsigned int output_processing;        /* Output processing option */
+   unsigned int data_encoding = P_NOTSET; /* Encoding libpng must produce */
+
+   /* Background information; the background color and the index of this color
+    * in the color-map if it exists (else 256).
+    */
+   unsigned int background_index = 256;
+   png_uint_32 back_r, back_g, back_b;
+
+   /* Flags to accumulate things that need to be done to the input. */
+   int expand_tRNS = 0;
+
+   /* Exclude the NYI feature of compositing onto a color-mapped buffer; it is
+    * very difficult to do, the results look awful, and it is difficult to see
+    * what possible use it is because the application can't control the
+    * color-map.
+    */
+   if (((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0 ||
+         png_ptr->num_trans > 0) /* alpha in input */ &&
+      ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) /* no alpha in output */)
+   {
+      if (output_encoding == P_LINEAR) /* compose on black */
+         back_b = back_g = back_r = 0;
+
+      else if (display->background == NULL /* no way to remove it */)
+         png_error(png_ptr,
+             "background color must be supplied to remove alpha/transparency");
+
+      /* Get a copy of the background color (this avoids repeating the checks
+       * below.)  The encoding is 8-bit sRGB or 16-bit linear, depending on the
+       * output format.
+       */
+      else
+      {
+         back_g = display->background->green;
+         if ((output_format & PNG_FORMAT_FLAG_COLOR) != 0)
+         {
+            back_r = display->background->red;
+            back_b = display->background->blue;
+         }
+         else
+            back_b = back_r = back_g;
+      }
+   }
+
+   else if (output_encoding == P_LINEAR)
+      back_b = back_r = back_g = 65535;
+
+   else
+      back_b = back_r = back_g = 255;
+
+   /* Default the input file gamma if required - this is necessary because
+    * libpng assumes that if no gamma information is present the data is in the
+    * output format, but the simplified API deduces the gamma from the input
+    * format.
+    */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0)
+   {
+      /* Do this directly, not using the png_colorspace functions, to ensure
+       * that it happens even if the colorspace is invalid (though probably if
+       * it is the setting will be ignored)  Note that the same thing can be
+       * achieved at the application interface with png_set_gAMA.
+       */
+      if (png_ptr->bit_depth == 16 &&
+         (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+         png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR;
+
+      else
+         png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE;
+
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+   }
+
+   /* Decide what to do based on the PNG color type of the input data.  The
+    * utility function png_create_colormap_entry deals with most aspects of the
+    * output transformations; this code works out how to produce bytes of
+    * color-map entries from the original format.
+    */
+   switch (png_ptr->color_type)
+   {
+      case PNG_COLOR_TYPE_GRAY:
+         if (png_ptr->bit_depth <= 8)
+         {
+            /* There at most 256 colors in the output, regardless of
+             * transparency.
+             */
+            unsigned int step, i, val, trans = 256/*ignore*/, back_alpha = 0;
+
+            cmap_entries = 1U << png_ptr->bit_depth;
+            if (cmap_entries > image->colormap_entries)
+               png_error(png_ptr, "gray[8] color-map: too few entries");
+
+            step = 255 / (cmap_entries - 1);
+            output_processing = PNG_CMAP_NONE;
+
+            /* If there is a tRNS chunk then this either selects a transparent
+             * value or, if the output has no alpha, the background color.
+             */
+            if (png_ptr->num_trans > 0)
+            {
+               trans = png_ptr->trans_color.gray;
+
+               if ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0)
+                  back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
+            }
+
+            /* png_create_colormap_entry just takes an RGBA and writes the
+             * corresponding color-map entry using the format from 'image',
+             * including the required conversion to sRGB or linear as
+             * appropriate.  The input values are always either sRGB (if the
+             * gamma correction flag is 0) or 0..255 scaled file encoded values
+             * (if the function must gamma correct them).
+             */
+            for (i=val=0; i<cmap_entries; ++i, val += step)
+            {
+               /* 'i' is a file value.  While this will result in duplicated
+                * entries for 8-bit non-sRGB encoded files it is necessary to
+                * have non-gamma corrected values to do tRNS handling.
+                */
+               if (i != trans)
+                  png_create_colormap_entry(display, i, val, val, val, 255,
+                      P_FILE/*8-bit with file gamma*/);
+
+               /* Else this entry is transparent.  The colors don't matter if
+                * there is an alpha channel (back_alpha == 0), but it does no
+                * harm to pass them in; the values are not set above so this
+                * passes in white.
+                *
+                * NOTE: this preserves the full precision of the application
+                * supplied background color when it is used.
+                */
+               else
+                  png_create_colormap_entry(display, i, back_r, back_g, back_b,
+                      back_alpha, output_encoding);
+            }
+
+            /* We need libpng to preserve the original encoding. */
+            data_encoding = P_FILE;
+
+            /* The rows from libpng, while technically gray values, are now also
+             * color-map indices; however, they may need to be expanded to 1
+             * byte per pixel.  This is what png_set_packing does (i.e., it
+             * unpacks the bit values into bytes.)
+             */
+            if (png_ptr->bit_depth < 8)
+               png_set_packing(png_ptr);
+         }
+
+         else /* bit depth is 16 */
+         {
+            /* The 16-bit input values can be converted directly to 8-bit gamma
+             * encoded values; however, if a tRNS chunk is present 257 color-map
+             * entries are required.  This means that the extra entry requires
+             * special processing; add an alpha channel, sacrifice gray level
+             * 254 and convert transparent (alpha==0) entries to that.
+             *
+             * Use libpng to chop the data to 8 bits.  Convert it to sRGB at the
+             * same time to minimize quality loss.  If a tRNS chunk is present
+             * this means libpng must handle it too; otherwise it is impossible
+             * to do the exact match on the 16-bit value.
+             *
+             * If the output has no alpha channel *and* the background color is
+             * gray then it is possible to let libpng handle the substitution by
+             * ensuring that the corresponding gray level matches the background
+             * color exactly.
+             */
+            data_encoding = P_sRGB;
+
+            if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
+               png_error(png_ptr, "gray[16] color-map: too few entries");
+
+            cmap_entries = (unsigned int)make_gray_colormap(display);
+
+            if (png_ptr->num_trans > 0)
+            {
+               unsigned int back_alpha;
+
+               if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+                  back_alpha = 0;
+
+               else
+               {
+                  if (back_r == back_g && back_g == back_b)
+                  {
+                     /* Background is gray; no special processing will be
+                      * required.
+                      */
+                     png_color_16 c;
+                     png_uint_32 gray = back_g;
+
+                     if (output_encoding == P_LINEAR)
+                     {
+                        gray = PNG_sRGB_FROM_LINEAR(gray * 255);
+
+                        /* And make sure the corresponding palette entry
+                         * matches.
+                         */
+                        png_create_colormap_entry(display, gray, back_g, back_g,
+                            back_g, 65535, P_LINEAR);
+                     }
+
+                     /* The background passed to libpng, however, must be the
+                      * sRGB value.
+                      */
+                     c.index = 0; /*unused*/
+                     c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
+
+                     /* NOTE: does this work without expanding tRNS to alpha?
+                      * It should be the color->gray case below apparently
+                      * doesn't.
+                      */
+                     png_set_background_fixed(png_ptr, &c,
+                         PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                         0/*gamma: not used*/);
+
+                     output_processing = PNG_CMAP_NONE;
+                     break;
+                  }
+#ifdef __COVERITY__
+                 /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
+                  * here.
+                  */
+                  back_alpha = 255;
+#else
+                  back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
+#endif
+               }
+
+               /* output_processing means that the libpng-processed row will be
+                * 8-bit GA and it has to be processing to single byte color-map
+                * values.  Entry 254 is replaced by either a completely
+                * transparent entry or by the background color at full
+                * precision (and the background color is not a simple gray
+                * level in this case.)
+                */
+               expand_tRNS = 1;
+               output_processing = PNG_CMAP_TRANS;
+               background_index = 254;
+
+               /* And set (overwrite) color-map entry 254 to the actual
+                * background color at full precision.
+                */
+               png_create_colormap_entry(display, 254, back_r, back_g, back_b,
+                   back_alpha, output_encoding);
+            }
+
+            else
+               output_processing = PNG_CMAP_NONE;
+         }
+         break;
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         /* 8-bit or 16-bit PNG with two channels - gray and alpha.  A minimum
+          * of 65536 combinations.  If, however, the alpha channel is to be
+          * removed there are only 256 possibilities if the background is gray.
+          * (Otherwise there is a subset of the 65536 possibilities defined by
+          * the triangle between black, white and the background color.)
+          *
+          * Reduce 16-bit files to 8-bit and sRGB encode the result.  No need to
+          * worry about tRNS matching - tRNS is ignored if there is an alpha
+          * channel.
+          */
+         data_encoding = P_sRGB;
+
+         if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         {
+            if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
+               png_error(png_ptr, "gray+alpha color-map: too few entries");
+
+            cmap_entries = (unsigned int)make_ga_colormap(display);
+
+            background_index = PNG_CMAP_GA_BACKGROUND;
+            output_processing = PNG_CMAP_GA;
+         }
+
+         else /* alpha is removed */
+         {
+            /* Alpha must be removed as the PNG data is processed when the
+             * background is a color because the G and A channels are
+             * independent and the vector addition (non-parallel vectors) is a
+             * 2-D problem.
+             *
+             * This can be reduced to the same algorithm as above by making a
+             * colormap containing gray levels (for the opaque grays), a
+             * background entry (for a transparent pixel) and a set of four six
+             * level color values, one set for each intermediate alpha value.
+             * See the comments in make_ga_colormap for how this works in the
+             * per-pixel processing.
+             *
+             * If the background is gray, however, we only need a 256 entry gray
+             * level color map.  It is sufficient to make the entry generated
+             * for the background color be exactly the color specified.
+             */
+            if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0 ||
+               (back_r == back_g && back_g == back_b))
+            {
+               /* Background is gray; no special processing will be required. */
+               png_color_16 c;
+               png_uint_32 gray = back_g;
+
+               if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "gray-alpha color-map: too few entries");
+
+               cmap_entries = (unsigned int)make_gray_colormap(display);
+
+               if (output_encoding == P_LINEAR)
+               {
+                  gray = PNG_sRGB_FROM_LINEAR(gray * 255);
+
+                  /* And make sure the corresponding palette entry matches. */
+                  png_create_colormap_entry(display, gray, back_g, back_g,
+                      back_g, 65535, P_LINEAR);
+               }
+
+               /* The background passed to libpng, however, must be the sRGB
+                * value.
+                */
+               c.index = 0; /*unused*/
+               c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
+
+               png_set_background_fixed(png_ptr, &c,
+                   PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                   0/*gamma: not used*/);
+
+               output_processing = PNG_CMAP_NONE;
+            }
+
+            else
+            {
+               png_uint_32 i, a;
+
+               /* This is the same as png_make_ga_colormap, above, except that
+                * the entries are all opaque.
+                */
+               if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "ga-alpha color-map: too few entries");
+
+               i = 0;
+               while (i < 231)
+               {
+                  png_uint_32 gray = (i * 256 + 115) / 231;
+                  png_create_colormap_entry(display, i++, gray, gray, gray,
+                      255, P_sRGB);
+               }
+
+               /* NOTE: this preserves the full precision of the application
+                * background color.
+                */
+               background_index = i;
+               png_create_colormap_entry(display, i++, back_r, back_g, back_b,
+#ifdef __COVERITY__
+                   /* Coverity claims that output_encoding
+                    * cannot be 2 (P_LINEAR) here.
+                    */ 255U,
+#else
+                    output_encoding == P_LINEAR ? 65535U : 255U,
+#endif
+                    output_encoding);
+
+               /* For non-opaque input composite on the sRGB background - this
+                * requires inverting the encoding for each component.  The input
+                * is still converted to the sRGB encoding because this is a
+                * reasonable approximate to the logarithmic curve of human
+                * visual sensitivity, at least over the narrow range which PNG
+                * represents.  Consequently 'G' is always sRGB encoded, while
+                * 'A' is linear.  We need the linear background colors.
+                */
+               if (output_encoding == P_sRGB) /* else already linear */
+               {
+                  /* This may produce a value not exactly matching the
+                   * background, but that's ok because these numbers are only
+                   * used when alpha != 0
+                   */
+                  back_r = png_sRGB_table[back_r];
+                  back_g = png_sRGB_table[back_g];
+                  back_b = png_sRGB_table[back_b];
+               }
+
+               for (a=1; a<5; ++a)
+               {
+                  unsigned int g;
+
+                  /* PNG_sRGB_FROM_LINEAR expects a 16-bit linear value scaled
+                   * by an 8-bit alpha value (0..255).
+                   */
+                  png_uint_32 alpha = 51 * a;
+                  png_uint_32 back_rx = (255-alpha) * back_r;
+                  png_uint_32 back_gx = (255-alpha) * back_g;
+                  png_uint_32 back_bx = (255-alpha) * back_b;
+
+                  for (g=0; g<6; ++g)
+                  {
+                     png_uint_32 gray = png_sRGB_table[g*51] * alpha;
+
+                     png_create_colormap_entry(display, i++,
+                         PNG_sRGB_FROM_LINEAR(gray + back_rx),
+                         PNG_sRGB_FROM_LINEAR(gray + back_gx),
+                         PNG_sRGB_FROM_LINEAR(gray + back_bx), 255, P_sRGB);
+                  }
+               }
+
+               cmap_entries = i;
+               output_processing = PNG_CMAP_GA;
+            }
+         }
+         break;
+
+      case PNG_COLOR_TYPE_RGB:
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         /* Exclude the case where the output is gray; we can always handle this
+          * with the cases above.
+          */
+         if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0)
+         {
+            /* The color-map will be grayscale, so we may as well convert the
+             * input RGB values to a simple grayscale and use the grayscale
+             * code above.
+             *
+             * NOTE: calling this apparently damages the recognition of the
+             * transparent color in background color handling; call
+             * png_set_tRNS_to_alpha before png_set_background_fixed.
+             */
+            png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, -1,
+                -1);
+            data_encoding = P_sRGB;
+
+            /* The output will now be one or two 8-bit gray or gray+alpha
+             * channels.  The more complex case arises when the input has alpha.
+             */
+            if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+               png_ptr->num_trans > 0) &&
+               (output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            {
+               /* Both input and output have an alpha channel, so no background
+                * processing is required; just map the GA bytes to the right
+                * color-map entry.
+                */
+               expand_tRNS = 1;
+
+               if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "rgb[ga] color-map: too few entries");
+
+               cmap_entries = (unsigned int)make_ga_colormap(display);
+               background_index = PNG_CMAP_GA_BACKGROUND;
+               output_processing = PNG_CMAP_GA;
+            }
+
+            else
+            {
+               /* Either the input or the output has no alpha channel, so there
+                * will be no non-opaque pixels in the color-map; it will just be
+                * grayscale.
+                */
+               if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "rgb[gray] color-map: too few entries");
+
+               /* Ideally this code would use libpng to do the gamma correction,
+                * but if an input alpha channel is to be removed we will hit the
+                * libpng bug in gamma+compose+rgb-to-gray (the double gamma
+                * correction bug).  Fix this by dropping the gamma correction in
+                * this case and doing it in the palette; this will result in
+                * duplicate palette entries, but that's better than the
+                * alternative of double gamma correction.
+                */
+               if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+                  png_ptr->num_trans > 0) &&
+                  png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
+               {
+                  cmap_entries = (unsigned int)make_gray_file_colormap(display);
+                  data_encoding = P_FILE;
+               }
+
+               else
+                  cmap_entries = (unsigned int)make_gray_colormap(display);
+
+               /* But if the input has alpha or transparency it must be removed
+                */
+               if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+                  png_ptr->num_trans > 0)
+               {
+                  png_color_16 c;
+                  png_uint_32 gray = back_g;
+
+                  /* We need to ensure that the application background exists in
+                   * the colormap and that completely transparent pixels map to
+                   * it.  Achieve this simply by ensuring that the entry
+                   * selected for the background really is the background color.
+                   */
+                  if (data_encoding == P_FILE) /* from the fixup above */
+                  {
+                     /* The app supplied a gray which is in output_encoding, we
+                      * need to convert it to a value of the input (P_FILE)
+                      * encoding then set this palette entry to the required
+                      * output encoding.
+                      */
+                     if (output_encoding == P_sRGB)
+                        gray = png_sRGB_table[gray]; /* now P_LINEAR */
+
+                     gray = PNG_DIV257(png_gamma_16bit_correct(gray,
+                         png_ptr->colorspace.gamma)); /* now P_FILE */
+
+                     /* And make sure the corresponding palette entry contains
+                      * exactly the required sRGB value.
+                      */
+                     png_create_colormap_entry(display, gray, back_g, back_g,
+                         back_g, 0/*unused*/, output_encoding);
+                  }
+
+                  else if (output_encoding == P_LINEAR)
+                  {
+                     gray = PNG_sRGB_FROM_LINEAR(gray * 255);
+
+                     /* And make sure the corresponding palette entry matches.
+                      */
+                     png_create_colormap_entry(display, gray, back_g, back_g,
+                        back_g, 0/*unused*/, P_LINEAR);
+                  }
+
+                  /* The background passed to libpng, however, must be the
+                   * output (normally sRGB) value.
+                   */
+                  c.index = 0; /*unused*/
+                  c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
+
+                  /* NOTE: the following is apparently a bug in libpng. Without
+                   * it the transparent color recognition in
+                   * png_set_background_fixed seems to go wrong.
+                   */
+                  expand_tRNS = 1;
+                  png_set_background_fixed(png_ptr, &c,
+                      PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                      0/*gamma: not used*/);
+               }
+
+               output_processing = PNG_CMAP_NONE;
+            }
+         }
+
+         else /* output is color */
+         {
+            /* We could use png_quantize here so long as there is no transparent
+             * color or alpha; png_quantize ignores alpha.  Easier overall just
+             * to do it once and using PNG_DIV51 on the 6x6x6 reduced RGB cube.
+             * Consequently we always want libpng to produce sRGB data.
+             */
+            data_encoding = P_sRGB;
+
+            /* Is there any transparency or alpha? */
+            if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+               png_ptr->num_trans > 0)
+            {
+               /* Is there alpha in the output too?  If so all four channels are
+                * processed into a special RGB cube with alpha support.
+                */
+               if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+               {
+                  png_uint_32 r;
+
+                  if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
+                     png_error(png_ptr, "rgb+alpha color-map: too few entries");
+
+                  cmap_entries = (unsigned int)make_rgb_colormap(display);
+
+                  /* Add a transparent entry. */
+                  png_create_colormap_entry(display, cmap_entries, 255, 255,
+                      255, 0, P_sRGB);
+
+                  /* This is stored as the background index for the processing
+                   * algorithm.
+                   */
+                  background_index = cmap_entries++;
+
+                  /* Add 27 r,g,b entries each with alpha 0.5. */
+                  for (r=0; r<256; r = (r << 1) | 0x7f)
+                  {
+                     png_uint_32 g;
+
+                     for (g=0; g<256; g = (g << 1) | 0x7f)
+                     {
+                        png_uint_32 b;
+
+                        /* This generates components with the values 0, 127 and
+                         * 255
+                         */
+                        for (b=0; b<256; b = (b << 1) | 0x7f)
+                           png_create_colormap_entry(display, cmap_entries++,
+                               r, g, b, 128, P_sRGB);
+                     }
+                  }
+
+                  expand_tRNS = 1;
+                  output_processing = PNG_CMAP_RGB_ALPHA;
+               }
+
+               else
+               {
+                  /* Alpha/transparency must be removed.  The background must
+                   * exist in the color map (achieved by setting adding it after
+                   * the 666 color-map).  If the standard processing code will
+                   * pick up this entry automatically that's all that is
+                   * required; libpng can be called to do the background
+                   * processing.
+                   */
+                  unsigned int sample_size =
+                     PNG_IMAGE_SAMPLE_SIZE(output_format);
+                  png_uint_32 r, g, b; /* sRGB background */
+
+                  if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
+                     png_error(png_ptr, "rgb-alpha color-map: too few entries");
+
+                  cmap_entries = (unsigned int)make_rgb_colormap(display);
+
+                  png_create_colormap_entry(display, cmap_entries, back_r,
+                      back_g, back_b, 0/*unused*/, output_encoding);
+
+                  if (output_encoding == P_LINEAR)
+                  {
+                     r = PNG_sRGB_FROM_LINEAR(back_r * 255);
+                     g = PNG_sRGB_FROM_LINEAR(back_g * 255);
+                     b = PNG_sRGB_FROM_LINEAR(back_b * 255);
+                  }
+
+                  else
+                  {
+                     r = back_r;
+                     g = back_g;
+                     b = back_g;
+                  }
+
+                  /* Compare the newly-created color-map entry with the one the
+                   * PNG_CMAP_RGB algorithm will use.  If the two entries don't
+                   * match, add the new one and set this as the background
+                   * index.
+                   */
+                  if (memcmp((png_const_bytep)display->colormap +
+                      sample_size * cmap_entries,
+                      (png_const_bytep)display->colormap +
+                          sample_size * PNG_RGB_INDEX(r,g,b),
+                     sample_size) != 0)
+                  {
+                     /* The background color must be added. */
+                     background_index = cmap_entries++;
+
+                     /* Add 27 r,g,b entries each with created by composing with
+                      * the background at alpha 0.5.
+                      */
+                     for (r=0; r<256; r = (r << 1) | 0x7f)
+                     {
+                        for (g=0; g<256; g = (g << 1) | 0x7f)
+                        {
+                           /* This generates components with the values 0, 127
+                            * and 255
+                            */
+                           for (b=0; b<256; b = (b << 1) | 0x7f)
+                              png_create_colormap_entry(display, cmap_entries++,
+                                  png_colormap_compose(display, r, P_sRGB, 128,
+                                      back_r, output_encoding),
+                                  png_colormap_compose(display, g, P_sRGB, 128,
+                                      back_g, output_encoding),
+                                  png_colormap_compose(display, b, P_sRGB, 128,
+                                      back_b, output_encoding),
+                                  0/*unused*/, output_encoding);
+                        }
+                     }
+
+                     expand_tRNS = 1;
+                     output_processing = PNG_CMAP_RGB_ALPHA;
+                  }
+
+                  else /* background color is in the standard color-map */
+                  {
+                     png_color_16 c;
+
+                     c.index = 0; /*unused*/
+                     c.red = (png_uint_16)back_r;
+                     c.gray = c.green = (png_uint_16)back_g;
+                     c.blue = (png_uint_16)back_b;
+
+                     png_set_background_fixed(png_ptr, &c,
+                         PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                         0/*gamma: not used*/);
+
+                     output_processing = PNG_CMAP_RGB;
+                  }
+               }
+            }
+
+            else /* no alpha or transparency in the input */
+            {
+               /* Alpha in the output is irrelevant, simply map the opaque input
+                * pixels to the 6x6x6 color-map.
+                */
+               if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "rgb color-map: too few entries");
+
+               cmap_entries = (unsigned int)make_rgb_colormap(display);
+               output_processing = PNG_CMAP_RGB;
+            }
+         }
+         break;
+
+      case PNG_COLOR_TYPE_PALETTE:
+         /* It's already got a color-map.  It may be necessary to eliminate the
+          * tRNS entries though.
+          */
+         {
+            unsigned int num_trans = png_ptr->num_trans;
+            png_const_bytep trans = num_trans > 0 ? png_ptr->trans_alpha : NULL;
+            png_const_colorp colormap = png_ptr->palette;
+            int do_background = trans != NULL &&
+               (output_format & PNG_FORMAT_FLAG_ALPHA) == 0;
+            unsigned int i;
+
+            /* Just in case: */
+            if (trans == NULL)
+               num_trans = 0;
+
+            output_processing = PNG_CMAP_NONE;
+            data_encoding = P_FILE; /* Don't change from color-map indices */
+            cmap_entries = (unsigned int)png_ptr->num_palette;
+            if (cmap_entries > 256)
+               cmap_entries = 256;
+
+            if (cmap_entries > (unsigned int)image->colormap_entries)
+               png_error(png_ptr, "palette color-map: too few entries");
+
+            for (i=0; i < cmap_entries; ++i)
+            {
+               if (do_background != 0 && i < num_trans && trans[i] < 255)
+               {
+                  if (trans[i] == 0)
+                     png_create_colormap_entry(display, i, back_r, back_g,
+                         back_b, 0, output_encoding);
+
+                  else
+                  {
+                     /* Must compose the PNG file color in the color-map entry
+                      * on the sRGB color in 'back'.
+                      */
+                     png_create_colormap_entry(display, i,
+                         png_colormap_compose(display, colormap[i].red,
+                             P_FILE, trans[i], back_r, output_encoding),
+                         png_colormap_compose(display, colormap[i].green,
+                             P_FILE, trans[i], back_g, output_encoding),
+                         png_colormap_compose(display, colormap[i].blue,
+                             P_FILE, trans[i], back_b, output_encoding),
+                         output_encoding == P_LINEAR ? trans[i] * 257U :
+                             trans[i],
+                         output_encoding);
+                  }
+               }
+
+               else
+                  png_create_colormap_entry(display, i, colormap[i].red,
+                      colormap[i].green, colormap[i].blue,
+                      i < num_trans ? trans[i] : 255U, P_FILE/*8-bit*/);
+            }
+
+            /* The PNG data may have indices packed in fewer than 8 bits, it
+             * must be expanded if so.
+             */
+            if (png_ptr->bit_depth < 8)
+               png_set_packing(png_ptr);
+         }
+         break;
+
+      default:
+         png_error(png_ptr, "invalid PNG color type");
+         /*NOT REACHED*/
+   }
+
+   /* Now deal with the output processing */
+   if (expand_tRNS != 0 && png_ptr->num_trans > 0 &&
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
+      png_set_tRNS_to_alpha(png_ptr);
+
+   switch (data_encoding)
+   {
+      case P_sRGB:
+         /* Change to 8-bit sRGB */
+         png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB);
+         /* FALLTHROUGH */
+
+      case P_FILE:
+         if (png_ptr->bit_depth > 8)
+            png_set_scale_16(png_ptr);
+         break;
+
+#ifdef __GNUC__
+      default:
+         png_error(png_ptr, "bad data option (internal error)");
+#endif
+   }
+
+   if (cmap_entries > 256 || cmap_entries > image->colormap_entries)
+      png_error(png_ptr, "color map overflow (BAD internal error)");
+
+   image->colormap_entries = cmap_entries;
+
+   /* Double check using the recorded background index */
+   switch (output_processing)
+   {
+      case PNG_CMAP_NONE:
+         if (background_index != PNG_CMAP_NONE_BACKGROUND)
+            goto bad_background;
+         break;
+
+      case PNG_CMAP_GA:
+         if (background_index != PNG_CMAP_GA_BACKGROUND)
+            goto bad_background;
+         break;
+
+      case PNG_CMAP_TRANS:
+         if (background_index >= cmap_entries ||
+            background_index != PNG_CMAP_TRANS_BACKGROUND)
+            goto bad_background;
+         break;
+
+      case PNG_CMAP_RGB:
+         if (background_index != PNG_CMAP_RGB_BACKGROUND)
+            goto bad_background;
+         break;
+
+      case PNG_CMAP_RGB_ALPHA:
+         if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND)
+            goto bad_background;
+         break;
+
+      default:
+         png_error(png_ptr, "bad processing option (internal error)");
+
+      bad_background:
+         png_error(png_ptr, "bad background index (internal error)");
+   }
+
+   display->colormap_processing = (int)output_processing;
+
+   return 1/*ok*/;
+}
+
+/* The final part of the color-map read called from png_image_finish_read. */
+static int
+png_image_read_and_map(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   int passes;
+
+   /* Called when the libpng data must be transformed into the color-mapped
+    * form.  There is a local row buffer in display->local and this routine must
+    * do the interlace handling.
+    */
+   switch (png_ptr->interlaced)
+   {
+      case PNG_INTERLACE_NONE:
+         passes = 1;
+         break;
+
+      case PNG_INTERLACE_ADAM7:
+         passes = PNG_INTERLACE_ADAM7_PASSES;
+         break;
+
+      default:
+         png_error(png_ptr, "unknown interlace type");
+   }
+
+   {
+      png_uint_32  height = image->height;
+      png_uint_32  width = image->width;
+      int          proc = display->colormap_processing;
+      png_bytep    first_row = png_voidcast(png_bytep, display->first_row);
+      ptrdiff_t    step_row = display->row_bytes;
+      int pass;
+
+      for (pass = 0; pass < passes; ++pass)
+      {
+         unsigned int     startx, stepx, stepy;
+         png_uint_32      y;
+
+         if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+         {
+            /* The row may be empty for a short image: */
+            if (PNG_PASS_COLS(width, pass) == 0)
+               continue;
+
+            startx = PNG_PASS_START_COL(pass);
+            stepx = PNG_PASS_COL_OFFSET(pass);
+            y = PNG_PASS_START_ROW(pass);
+            stepy = PNG_PASS_ROW_OFFSET(pass);
+         }
+
+         else
+         {
+            y = 0;
+            startx = 0;
+            stepx = stepy = 1;
+         }
+
+         for (; y<height; y += stepy)
+         {
+            png_bytep inrow = png_voidcast(png_bytep, display->local_row);
+            png_bytep outrow = first_row + y * step_row;
+            png_const_bytep end_row = outrow + width;
+
+            /* Read read the libpng data into the temporary buffer. */
+            png_read_row(png_ptr, inrow, NULL);
+
+            /* Now process the row according to the processing option, note
+             * that the caller verifies that the format of the libpng output
+             * data is as required.
+             */
+            outrow += startx;
+            switch (proc)
+            {
+               case PNG_CMAP_GA:
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     /* The data is always in the PNG order */
+                     unsigned int gray = *inrow++;
+                     unsigned int alpha = *inrow++;
+                     unsigned int entry;
+
+                     /* NOTE: this code is copied as a comment in
+                      * make_ga_colormap above.  Please update the
+                      * comment if you change this code!
+                      */
+                     if (alpha > 229) /* opaque */
+                     {
+                        entry = (231 * gray + 128) >> 8;
+                     }
+                     else if (alpha < 26) /* transparent */
+                     {
+                        entry = 231;
+                     }
+                     else /* partially opaque */
+                     {
+                        entry = 226 + 6 * PNG_DIV51(alpha) + PNG_DIV51(gray);
+                     }
+
+                     *outrow = (png_byte)entry;
+                  }
+                  break;
+
+               case PNG_CMAP_TRANS:
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     png_byte gray = *inrow++;
+                     png_byte alpha = *inrow++;
+
+                     if (alpha == 0)
+                        *outrow = PNG_CMAP_TRANS_BACKGROUND;
+
+                     else if (gray != PNG_CMAP_TRANS_BACKGROUND)
+                        *outrow = gray;
+
+                     else
+                        *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1);
+                  }
+                  break;
+
+               case PNG_CMAP_RGB:
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], inrow[2]);
+                     inrow += 3;
+                  }
+                  break;
+
+               case PNG_CMAP_RGB_ALPHA:
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     unsigned int alpha = inrow[3];
+
+                     /* Because the alpha entries only hold alpha==0.5 values
+                      * split the processing at alpha==0.25 (64) and 0.75
+                      * (196).
+                      */
+
+                     if (alpha >= 196)
+                        *outrow = PNG_RGB_INDEX(inrow[0], inrow[1],
+                            inrow[2]);
+
+                     else if (alpha < 64)
+                        *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND;
+
+                     else
+                     {
+                        /* Likewise there are three entries for each of r, g
+                         * and b.  We could select the entry by popcount on
+                         * the top two bits on those architectures that
+                         * support it, this is what the code below does,
+                         * crudely.
+                         */
+                        unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1;
+
+                        /* Here are how the values map:
+                         *
+                         * 0x00 .. 0x3f -> 0
+                         * 0x40 .. 0xbf -> 1
+                         * 0xc0 .. 0xff -> 2
+                         *
+                         * So, as above with the explicit alpha checks, the
+                         * breakpoints are at 64 and 196.
+                         */
+                        if (inrow[0] & 0x80) back_i += 9; /* red */
+                        if (inrow[0] & 0x40) back_i += 9;
+                        if (inrow[0] & 0x80) back_i += 3; /* green */
+                        if (inrow[0] & 0x40) back_i += 3;
+                        if (inrow[0] & 0x80) back_i += 1; /* blue */
+                        if (inrow[0] & 0x40) back_i += 1;
+
+                        *outrow = (png_byte)back_i;
+                     }
+
+                     inrow += 4;
+                  }
+                  break;
+
+               default:
+                  break;
+            }
+         }
+      }
+   }
+
+   return 1;
+}
+
+static int
+png_image_read_colormapped(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_controlp control = image->opaque;
+   png_structrp png_ptr = control->png_ptr;
+   png_inforp info_ptr = control->info_ptr;
+
+   int passes = 0; /* As a flag */
+
+   PNG_SKIP_CHUNKS(png_ptr);
+
+   /* Update the 'info' structure and make sure the result is as required; first
+    * make sure to turn on the interlace handling if it will be required
+    * (because it can't be turned on *after* the call to png_read_update_info!)
+    */
+   if (display->colormap_processing == PNG_CMAP_NONE)
+      passes = png_set_interlace_handling(png_ptr);
+
+   png_read_update_info(png_ptr, info_ptr);
+
+   /* The expected output can be deduced from the colormap_processing option. */
+   switch (display->colormap_processing)
+   {
+      case PNG_CMAP_NONE:
+         /* Output must be one channel and one byte per pixel, the output
+          * encoding can be anything.
+          */
+         if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
+            info_ptr->color_type == PNG_COLOR_TYPE_GRAY) &&
+            info_ptr->bit_depth == 8)
+            break;
+
+         goto bad_output;
+
+      case PNG_CMAP_TRANS:
+      case PNG_CMAP_GA:
+         /* Output must be two channels and the 'G' one must be sRGB, the latter
+          * can be checked with an exact number because it should have been set
+          * to this number above!
+          */
+         if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+            info_ptr->bit_depth == 8 &&
+            png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
+            image->colormap_entries == 256)
+            break;
+
+         goto bad_output;
+
+      case PNG_CMAP_RGB:
+         /* Output must be 8-bit sRGB encoded RGB */
+         if (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+            info_ptr->bit_depth == 8 &&
+            png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
+            image->colormap_entries == 216)
+            break;
+
+         goto bad_output;
+
+      case PNG_CMAP_RGB_ALPHA:
+         /* Output must be 8-bit sRGB encoded RGBA */
+         if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+            info_ptr->bit_depth == 8 &&
+            png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
+            image->colormap_entries == 244 /* 216 + 1 + 27 */)
+            break;
+
+         goto bad_output;
+
+      default:
+      bad_output:
+         png_error(png_ptr, "bad color-map processing (internal error)");
+   }
+
+   /* Now read the rows.  Do this here if it is possible to read directly into
+    * the output buffer, otherwise allocate a local row buffer of the maximum
+    * size libpng requires and call the relevant processing routine safely.
+    */
+   {
+      png_voidp first_row = display->buffer;
+      ptrdiff_t row_bytes = display->row_stride;
+
+      /* The following expression is designed to work correctly whether it gives
+       * a signed or an unsigned result.
+       */
+      if (row_bytes < 0)
+      {
+         char *ptr = png_voidcast(char*, first_row);
+         ptr += (image->height-1) * (-row_bytes);
+         first_row = png_voidcast(png_voidp, ptr);
+      }
+
+      display->first_row = first_row;
+      display->row_bytes = row_bytes;
+   }
+
+   if (passes == 0)
+   {
+      int result;
+      png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
+
+      display->local_row = row;
+      result = png_safe_execute(image, png_image_read_and_map, display);
+      display->local_row = NULL;
+      png_free(png_ptr, row);
+
+      return result;
+   }
+
+   else
+   {
+      png_alloc_size_t row_bytes = (png_alloc_size_t)display->row_bytes;
+
+      while (--passes >= 0)
+      {
+         png_uint_32      y = image->height;
+         png_bytep        row = png_voidcast(png_bytep, display->first_row);
+
+         for (; y > 0; --y)
+         {
+            png_read_row(png_ptr, row, NULL);
+            row += row_bytes;
+         }
+      }
+
+      return 1;
+   }
+}
+
+/* Just the row reading part of png_image_read. */
+static int
+png_image_read_composite(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   int passes;
+
+   switch (png_ptr->interlaced)
+   {
+      case PNG_INTERLACE_NONE:
+         passes = 1;
+         break;
+
+      case PNG_INTERLACE_ADAM7:
+         passes = PNG_INTERLACE_ADAM7_PASSES;
+         break;
+
+      default:
+         png_error(png_ptr, "unknown interlace type");
+   }
+
+   {
+      png_uint_32  height = image->height;
+      png_uint_32  width = image->width;
+      ptrdiff_t    step_row = display->row_bytes;
+      unsigned int channels =
+          (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
+      int pass;
+
+      for (pass = 0; pass < passes; ++pass)
+      {
+         unsigned int     startx, stepx, stepy;
+         png_uint_32      y;
+
+         if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+         {
+            /* The row may be empty for a short image: */
+            if (PNG_PASS_COLS(width, pass) == 0)
+               continue;
+
+            startx = PNG_PASS_START_COL(pass) * channels;
+            stepx = PNG_PASS_COL_OFFSET(pass) * channels;
+            y = PNG_PASS_START_ROW(pass);
+            stepy = PNG_PASS_ROW_OFFSET(pass);
+         }
+
+         else
+         {
+            y = 0;
+            startx = 0;
+            stepx = channels;
+            stepy = 1;
+         }
+
+         for (; y<height; y += stepy)
+         {
+            png_bytep inrow = png_voidcast(png_bytep, display->local_row);
+            png_bytep outrow;
+            png_const_bytep end_row;
+
+            /* Read the row, which is packed: */
+            png_read_row(png_ptr, inrow, NULL);
+
+            outrow = png_voidcast(png_bytep, display->first_row);
+            outrow += y * step_row;
+            end_row = outrow + width * channels;
+
+            /* Now do the composition on each pixel in this row. */
+            outrow += startx;
+            for (; outrow < end_row; outrow += stepx)
+            {
+               png_byte alpha = inrow[channels];
+
+               if (alpha > 0) /* else no change to the output */
+               {
+                  unsigned int c;
+
+                  for (c=0; c<channels; ++c)
+                  {
+                     png_uint_32 component = inrow[c];
+
+                     if (alpha < 255) /* else just use component */
+                     {
+                        /* This is PNG_OPTIMIZED_ALPHA, the component value
+                         * is a linear 8-bit value.  Combine this with the
+                         * current outrow[c] value which is sRGB encoded.
+                         * Arithmetic here is 16-bits to preserve the output
+                         * values correctly.
+                         */
+                        component *= 257*255; /* =65535 */
+                        component += (255-alpha)*png_sRGB_table[outrow[c]];
+
+                        /* So 'component' is scaled by 255*65535 and is
+                         * therefore appropriate for the sRGB to linear
+                         * conversion table.
+                         */
+                        component = PNG_sRGB_FROM_LINEAR(component);
+                     }
+
+                     outrow[c] = (png_byte)component;
+                  }
+               }
+
+               inrow += channels+1; /* components and alpha channel */
+            }
+         }
+      }
+   }
+
+   return 1;
+}
+
+/* The do_local_background case; called when all the following transforms are to
+ * be done:
+ *
+ * PNG_RGB_TO_GRAY
+ * PNG_COMPOSITE
+ * PNG_GAMMA
+ *
+ * This is a work-around for the fact that both the PNG_RGB_TO_GRAY and
+ * PNG_COMPOSITE code performs gamma correction, so we get double gamma
+ * correction.  The fix-up is to prevent the PNG_COMPOSITE operation from
+ * happening inside libpng, so this routine sees an 8 or 16-bit gray+alpha
+ * row and handles the removal or pre-multiplication of the alpha channel.
+ */
+static int
+png_image_read_background(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_inforp info_ptr = image->opaque->info_ptr;
+   png_uint_32 height = image->height;
+   png_uint_32 width = image->width;
+   int pass, passes;
+
+   /* Double check the convoluted logic below.  We expect to get here with
+    * libpng doing rgb to gray and gamma correction but background processing
+    * left to the png_image_read_background function.  The rows libpng produce
+    * might be 8 or 16-bit but should always have two channels; gray plus alpha.
+    */
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+      png_error(png_ptr, "lost rgb to gray");
+
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+      png_error(png_ptr, "unexpected compose");
+
+   if (png_get_channels(png_ptr, info_ptr) != 2)
+      png_error(png_ptr, "lost/gained channels");
+
+   /* Expect the 8-bit case to always remove the alpha channel */
+   if ((image->format & PNG_FORMAT_FLAG_LINEAR) == 0 &&
+      (image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+      png_error(png_ptr, "unexpected 8-bit transformation");
+
+   switch (png_ptr->interlaced)
+   {
+      case PNG_INTERLACE_NONE:
+         passes = 1;
+         break;
+
+      case PNG_INTERLACE_ADAM7:
+         passes = PNG_INTERLACE_ADAM7_PASSES;
+         break;
+
+      default:
+         png_error(png_ptr, "unknown interlace type");
+   }
+
+   /* Use direct access to info_ptr here because otherwise the simplified API
+    * would require PNG_EASY_ACCESS_SUPPORTED (just for this.)  Note this is
+    * checking the value after libpng expansions, not the original value in the
+    * PNG.
+    */
+   switch (info_ptr->bit_depth)
+   {
+      case 8:
+         /* 8-bit sRGB gray values with an alpha channel; the alpha channel is
+          * to be removed by composing on a background: either the row if
+          * display->background is NULL or display->background->green if not.
+          * Unlike the code above ALPHA_OPTIMIZED has *not* been done.
+          */
+         {
+            png_bytep first_row = png_voidcast(png_bytep, display->first_row);
+            ptrdiff_t step_row = display->row_bytes;
+
+            for (pass = 0; pass < passes; ++pass)
+            {
+               png_bytep row = png_voidcast(png_bytep, display->first_row);
+               unsigned int     startx, stepx, stepy;
+               png_uint_32      y;
+
+               if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+               {
+                  /* The row may be empty for a short image: */
+                  if (PNG_PASS_COLS(width, pass) == 0)
+                     continue;
+
+                  startx = PNG_PASS_START_COL(pass);
+                  stepx = PNG_PASS_COL_OFFSET(pass);
+                  y = PNG_PASS_START_ROW(pass);
+                  stepy = PNG_PASS_ROW_OFFSET(pass);
+               }
+
+               else
+               {
+                  y = 0;
+                  startx = 0;
+                  stepx = stepy = 1;
+               }
+
+               if (display->background == NULL)
+               {
+                  for (; y<height; y += stepy)
+                  {
+                     png_bytep inrow = png_voidcast(png_bytep,
+                         display->local_row);
+                     png_bytep outrow = first_row + y * step_row;
+                     png_const_bytep end_row = outrow + width;
+
+                     /* Read the row, which is packed: */
+                     png_read_row(png_ptr, inrow, NULL);
+
+                     /* Now do the composition on each pixel in this row. */
+                     outrow += startx;
+                     for (; outrow < end_row; outrow += stepx)
+                     {
+                        png_byte alpha = inrow[1];
+
+                        if (alpha > 0) /* else no change to the output */
+                        {
+                           png_uint_32 component = inrow[0];
+
+                           if (alpha < 255) /* else just use component */
+                           {
+                              /* Since PNG_OPTIMIZED_ALPHA was not set it is
+                               * necessary to invert the sRGB transfer
+                               * function and multiply the alpha out.
+                               */
+                              component = png_sRGB_table[component] * alpha;
+                              component += png_sRGB_table[outrow[0]] *
+                                 (255-alpha);
+                              component = PNG_sRGB_FROM_LINEAR(component);
+                           }
+
+                           outrow[0] = (png_byte)component;
+                        }
+
+                        inrow += 2; /* gray and alpha channel */
+                     }
+                  }
+               }
+
+               else /* constant background value */
+               {
+                  png_byte background8 = display->background->green;
+                  png_uint_16 background = png_sRGB_table[background8];
+
+                  for (; y<height; y += stepy)
+                  {
+                     png_bytep inrow = png_voidcast(png_bytep,
+                         display->local_row);
+                     png_bytep outrow = first_row + y * step_row;
+                     png_const_bytep end_row = outrow + width;
+
+                     /* Read the row, which is packed: */
+                     png_read_row(png_ptr, inrow, NULL);
+
+                     /* Now do the composition on each pixel in this row. */
+                     outrow += startx;
+                     for (; outrow < end_row; outrow += stepx)
+                     {
+                        png_byte alpha = inrow[1];
+
+                        if (alpha > 0) /* else use background */
+                        {
+                           png_uint_32 component = inrow[0];
+
+                           if (alpha < 255) /* else just use component */
+                           {
+                              component = png_sRGB_table[component] * alpha;
+                              component += background * (255-alpha);
+                              component = PNG_sRGB_FROM_LINEAR(component);
+                           }
+
+                           outrow[0] = (png_byte)component;
+                        }
+
+                        else
+                           outrow[0] = background8;
+
+                        inrow += 2; /* gray and alpha channel */
+                     }
+
+                     row += display->row_bytes;
+                  }
+               }
+            }
+         }
+         break;
+
+      case 16:
+         /* 16-bit linear with pre-multiplied alpha; the pre-multiplication must
+          * still be done and, maybe, the alpha channel removed.  This code also
+          * handles the alpha-first option.
+          */
+         {
+            png_uint_16p first_row = png_voidcast(png_uint_16p,
+                display->first_row);
+            /* The division by two is safe because the caller passed in a
+             * stride which was multiplied by 2 (below) to get row_bytes.
+             */
+            ptrdiff_t    step_row = display->row_bytes / 2;
+            unsigned int preserve_alpha = (image->format &
+                PNG_FORMAT_FLAG_ALPHA) != 0;
+            unsigned int outchannels = 1U+preserve_alpha;
+            int swap_alpha = 0;
+
+#           ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
+               if (preserve_alpha != 0 &&
+                   (image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+                  swap_alpha = 1;
+#           endif
+
+            for (pass = 0; pass < passes; ++pass)
+            {
+               unsigned int     startx, stepx, stepy;
+               png_uint_32      y;
+
+               /* The 'x' start and step are adjusted to output components here.
+                */
+               if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+               {
+                  /* The row may be empty for a short image: */
+                  if (PNG_PASS_COLS(width, pass) == 0)
+                     continue;
+
+                  startx = PNG_PASS_START_COL(pass) * outchannels;
+                  stepx = PNG_PASS_COL_OFFSET(pass) * outchannels;
+                  y = PNG_PASS_START_ROW(pass);
+                  stepy = PNG_PASS_ROW_OFFSET(pass);
+               }
+
+               else
+               {
+                  y = 0;
+                  startx = 0;
+                  stepx = outchannels;
+                  stepy = 1;
+               }
+
+               for (; y<height; y += stepy)
+               {
+                  png_const_uint_16p inrow;
+                  png_uint_16p outrow = first_row + y*step_row;
+                  png_uint_16p end_row = outrow + width * outchannels;
+
+                  /* Read the row, which is packed: */
+                  png_read_row(png_ptr, png_voidcast(png_bytep,
+                      display->local_row), NULL);
+                  inrow = png_voidcast(png_const_uint_16p, display->local_row);
+
+                  /* Now do the pre-multiplication on each pixel in this row.
+                   */
+                  outrow += startx;
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     png_uint_32 component = inrow[0];
+                     png_uint_16 alpha = inrow[1];
+
+                     if (alpha > 0) /* else 0 */
+                     {
+                        if (alpha < 65535) /* else just use component */
+                        {
+                           component *= alpha;
+                           component += 32767;
+                           component /= 65535;
+                        }
+                     }
+
+                     else
+                        component = 0;
+
+                     outrow[swap_alpha] = (png_uint_16)component;
+                     if (preserve_alpha != 0)
+                        outrow[1 ^ swap_alpha] = alpha;
+
+                     inrow += 2; /* components and alpha channel */
+                  }
+               }
+            }
+         }
+         break;
+
+#ifdef __GNUC__
+      default:
+         png_error(png_ptr, "unexpected bit depth");
+#endif
+   }
+
+   return 1;
+}
+
+/* The guts of png_image_finish_read as a png_safe_execute callback. */
+static int
+png_image_read_direct(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_inforp info_ptr = image->opaque->info_ptr;
+
+   png_uint_32 format = image->format;
+   int linear = (format & PNG_FORMAT_FLAG_LINEAR) != 0;
+   int do_local_compose = 0;
+   int do_local_background = 0; /* to avoid double gamma correction bug */
+   int passes = 0;
+
+   /* Add transforms to ensure the correct output format is produced then check
+    * that the required implementation support is there.  Always expand; always
+    * need 8 bits minimum, no palette and expanded tRNS.
+    */
+   png_set_expand(png_ptr);
+
+   /* Now check the format to see if it was modified. */
+   {
+      png_uint_32 base_format = png_image_format(png_ptr) &
+         ~PNG_FORMAT_FLAG_COLORMAP /* removed by png_set_expand */;
+      png_uint_32 change = format ^ base_format;
+      png_fixed_point output_gamma;
+      int mode; /* alpha mode */
+
+      /* Do this first so that we have a record if rgb to gray is happening. */
+      if ((change & PNG_FORMAT_FLAG_COLOR) != 0)
+      {
+         /* gray<->color transformation required. */
+         if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
+            png_set_gray_to_rgb(png_ptr);
+
+         else
+         {
+            /* libpng can't do both rgb to gray and
+             * background/pre-multiplication if there is also significant gamma
+             * correction, because both operations require linear colors and
+             * the code only supports one transform doing the gamma correction.
+             * Handle this by doing the pre-multiplication or background
+             * operation in this code, if necessary.
+             *
+             * TODO: fix this by rewriting pngrtran.c (!)
+             *
+             * For the moment (given that fixing this in pngrtran.c is an
+             * enormous change) 'do_local_background' is used to indicate that
+             * the problem exists.
+             */
+            if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+               do_local_background = 1/*maybe*/;
+
+            png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
+                PNG_RGB_TO_GRAY_DEFAULT, PNG_RGB_TO_GRAY_DEFAULT);
+         }
+
+         change &= ~PNG_FORMAT_FLAG_COLOR;
+      }
+
+      /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise.
+       */
+      {
+         png_fixed_point input_gamma_default;
+
+         if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
+             (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+            input_gamma_default = PNG_GAMMA_LINEAR;
+         else
+            input_gamma_default = PNG_DEFAULT_sRGB;
+
+         /* Call png_set_alpha_mode to set the default for the input gamma; the
+          * output gamma is set by a second call below.
+          */
+         png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, input_gamma_default);
+      }
+
+      if (linear != 0)
+      {
+         /* If there *is* an alpha channel in the input it must be multiplied
+          * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG.
+          */
+         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            mode = PNG_ALPHA_STANDARD; /* associated alpha */
+
+         else
+            mode = PNG_ALPHA_PNG;
+
+         output_gamma = PNG_GAMMA_LINEAR;
+      }
+
+      else
+      {
+         mode = PNG_ALPHA_PNG;
+         output_gamma = PNG_DEFAULT_sRGB;
+      }
+      
+      if ((change & PNG_FORMAT_FLAG_ASSOCIATED_ALPHA) != 0)
+      {
+         mode = PNG_ALPHA_OPTIMIZED;
+         change &= ~PNG_FORMAT_FLAG_ASSOCIATED_ALPHA;
+      }
+      
+      /* If 'do_local_background' is set check for the presence of gamma
+       * correction; this is part of the work-round for the libpng bug
+       * described above.
+       *
+       * TODO: fix libpng and remove this.
+       */
+      if (do_local_background != 0)
+      {
+         png_fixed_point gtest;
+
+         /* This is 'png_gamma_threshold' from pngrtran.c; the test used for
+          * gamma correction, the screen gamma hasn't been set on png_struct
+          * yet; it's set below.  png_struct::gamma, however, is set to the
+          * final value.
+          */
+         if (png_muldiv(&gtest, output_gamma, png_ptr->colorspace.gamma,
+             PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0)
+            do_local_background = 0;
+
+         else if (mode == PNG_ALPHA_STANDARD)
+         {
+            do_local_background = 2/*required*/;
+            mode = PNG_ALPHA_PNG; /* prevent libpng doing it */
+         }
+
+         /* else leave as 1 for the checks below */
+      }
+
+      /* If the bit-depth changes then handle that here. */
+      if ((change & PNG_FORMAT_FLAG_LINEAR) != 0)
+      {
+         if (linear != 0 /*16-bit output*/)
+            png_set_expand_16(png_ptr);
+
+         else /* 8-bit output */
+            png_set_scale_16(png_ptr);
+
+         change &= ~PNG_FORMAT_FLAG_LINEAR;
+      }
+
+      /* Now the background/alpha channel changes. */
+      if ((change & PNG_FORMAT_FLAG_ALPHA) != 0)
+      {
+         /* Removing an alpha channel requires composition for the 8-bit
+          * formats; for the 16-bit it is already done, above, by the
+          * pre-multiplication and the channel just needs to be stripped.
+          */
+         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         {
+            /* If RGB->gray is happening the alpha channel must be left and the
+             * operation completed locally.
+             *
+             * TODO: fix libpng and remove this.
+             */
+            if (do_local_background != 0)
+               do_local_background = 2/*required*/;
+
+            /* 16-bit output: just remove the channel */
+            else if (linear != 0) /* compose on black (well, pre-multiply) */
+               png_set_strip_alpha(png_ptr);
+
+            /* 8-bit output: do an appropriate compose */
+            else if (display->background != NULL)
+            {
+               png_color_16 c;
+
+               c.index = 0; /*unused*/
+               c.red = display->background->red;
+               c.green = display->background->green;
+               c.blue = display->background->blue;
+               c.gray = display->background->green;
+
+               /* This is always an 8-bit sRGB value, using the 'green' channel
+                * for gray is much better than calculating the luminance here;
+                * we can get off-by-one errors in that calculation relative to
+                * the app expectations and that will show up in transparent
+                * pixels.
+                */
+               png_set_background_fixed(png_ptr, &c,
+                   PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                   0/*gamma: not used*/);
+            }
+
+            else /* compose on row: implemented below. */
+            {
+               do_local_compose = 1;
+               /* This leaves the alpha channel in the output, so it has to be
+                * removed by the code below.  Set the encoding to the 'OPTIMIZE'
+                * one so the code only has to hack on the pixels that require
+                * composition.
+                */
+               mode = PNG_ALPHA_OPTIMIZED;
+            }
+         }
+
+         else /* output needs an alpha channel */
+         {
+            /* This is tricky because it happens before the swap operation has
+             * been accomplished; however, the swap does *not* swap the added
+             * alpha channel (weird API), so it must be added in the correct
+             * place.
+             */
+            png_uint_32 filler; /* opaque filler */
+            int where;
+
+            if (linear != 0)
+               filler = 65535;
+
+            else
+               filler = 255;
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+            if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+            {
+               where = PNG_FILLER_BEFORE;
+               change &= ~PNG_FORMAT_FLAG_AFIRST;
+            }
+
+            else
+#endif
+            where = PNG_FILLER_AFTER;
+
+            png_set_add_alpha(png_ptr, filler, where);
+         }
+
+         /* This stops the (irrelevant) call to swap_alpha below. */
+         change &= ~PNG_FORMAT_FLAG_ALPHA;
+      }
+
+      /* Now set the alpha mode correctly; this is always done, even if there is
+       * no alpha channel in either the input or the output because it correctly
+       * sets the output gamma.
+       */
+      png_set_alpha_mode_fixed(png_ptr, mode, output_gamma);
+
+#     ifdef PNG_FORMAT_BGR_SUPPORTED
+         if ((change & PNG_FORMAT_FLAG_BGR) != 0)
+         {
+            /* Check only the output format; PNG is never BGR; don't do this if
+             * the output is gray, but fix up the 'format' value in that case.
+             */
+            if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
+               png_set_bgr(png_ptr);
+
+            else
+               format &= ~PNG_FORMAT_FLAG_BGR;
+
+            change &= ~PNG_FORMAT_FLAG_BGR;
+         }
+#     endif
+
+#     ifdef PNG_FORMAT_AFIRST_SUPPORTED
+         if ((change & PNG_FORMAT_FLAG_AFIRST) != 0)
+         {
+            /* Only relevant if there is an alpha channel - it's particularly
+             * important to handle this correctly because do_local_compose may
+             * be set above and then libpng will keep the alpha channel for this
+             * code to remove.
+             */
+            if ((format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            {
+               /* Disable this if doing a local background,
+                * TODO: remove this when local background is no longer required.
+                */
+               if (do_local_background != 2)
+                  png_set_swap_alpha(png_ptr);
+            }
+
+            else
+               format &= ~PNG_FORMAT_FLAG_AFIRST;
+
+            change &= ~PNG_FORMAT_FLAG_AFIRST;
+         }
+#     endif
+
+      /* If the *output* is 16-bit then we need to check for a byte-swap on this
+       * architecture.
+       */
+      if (linear != 0)
+      {
+         png_uint_16 le = 0x0001;
+
+         if ((*(png_const_bytep) & le) != 0)
+            png_set_swap(png_ptr);
+      }
+
+      /* If change is not now 0 some transformation is missing - error out. */
+      if (change != 0)
+         png_error(png_ptr, "png_read_image: unsupported transformation");
+   }
+
+   PNG_SKIP_CHUNKS(png_ptr);
+
+   /* Update the 'info' structure and make sure the result is as required; first
+    * make sure to turn on the interlace handling if it will be required
+    * (because it can't be turned on *after* the call to png_read_update_info!)
+    *
+    * TODO: remove the do_local_background fixup below.
+    */
+   if (do_local_compose == 0 && do_local_background != 2)
+      passes = png_set_interlace_handling(png_ptr);
+
+   png_read_update_info(png_ptr, info_ptr);
+
+   {
+      png_uint_32 info_format = 0;
+
+      if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+         info_format |= PNG_FORMAT_FLAG_COLOR;
+
+      if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      {
+         /* do_local_compose removes this channel below. */
+         if (do_local_compose == 0)
+         {
+            /* do_local_background does the same if required. */
+            if (do_local_background != 2 ||
+               (format & PNG_FORMAT_FLAG_ALPHA) != 0)
+               info_format |= PNG_FORMAT_FLAG_ALPHA;
+         }
+      }
+
+      else if (do_local_compose != 0) /* internal error */
+         png_error(png_ptr, "png_image_read: alpha channel lost");
+
+      if ((format & PNG_FORMAT_FLAG_ASSOCIATED_ALPHA) != 0) {
+         info_format |= PNG_FORMAT_FLAG_ASSOCIATED_ALPHA;
+      }
+
+      if (info_ptr->bit_depth == 16)
+         info_format |= PNG_FORMAT_FLAG_LINEAR;
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+      if ((png_ptr->transformations & PNG_BGR) != 0)
+         info_format |= PNG_FORMAT_FLAG_BGR;
+#endif
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+         if (do_local_background == 2)
+         {
+            if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+               info_format |= PNG_FORMAT_FLAG_AFIRST;
+         }
+
+         if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0 ||
+            ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 &&
+            (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0))
+         {
+            if (do_local_background == 2)
+               png_error(png_ptr, "unexpected alpha swap transformation");
+
+            info_format |= PNG_FORMAT_FLAG_AFIRST;
+         }
+#     endif
+
+      /* This is actually an internal error. */
+      if (info_format != format)
+         png_error(png_ptr, "png_read_image: invalid transformations");
+   }
+
+   /* Now read the rows.  If do_local_compose is set then it is necessary to use
+    * a local row buffer.  The output will be GA, RGBA or BGRA and must be
+    * converted to G, RGB or BGR as appropriate.  The 'local_row' member of the
+    * display acts as a flag.
+    */
+   {
+      png_voidp first_row = display->buffer;
+      ptrdiff_t row_bytes = display->row_stride;
+
+      if (linear != 0)
+         row_bytes *= 2;
+
+      /* The following expression is designed to work correctly whether it gives
+       * a signed or an unsigned result.
+       */
+      if (row_bytes < 0)
+      {
+         char *ptr = png_voidcast(char*, first_row);
+         ptr += (image->height-1) * (-row_bytes);
+         first_row = png_voidcast(png_voidp, ptr);
+      }
+
+      display->first_row = first_row;
+      display->row_bytes = row_bytes;
+   }
+
+   if (do_local_compose != 0)
+   {
+      int result;
+      png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
+
+      display->local_row = row;
+      result = png_safe_execute(image, png_image_read_composite, display);
+      display->local_row = NULL;
+      png_free(png_ptr, row);
+
+      return result;
+   }
+
+   else if (do_local_background == 2)
+   {
+      int result;
+      png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
+
+      display->local_row = row;
+      result = png_safe_execute(image, png_image_read_background, display);
+      display->local_row = NULL;
+      png_free(png_ptr, row);
+
+      return result;
+   }
+
+   else
+   {
+      png_alloc_size_t row_bytes = (png_alloc_size_t)display->row_bytes;
+
+      while (--passes >= 0)
+      {
+         png_uint_32      y = image->height;
+         png_bytep        row = png_voidcast(png_bytep, display->first_row);
+
+         for (; y > 0; --y)
+         {
+            png_read_row(png_ptr, row, NULL);
+            row += row_bytes;
+         }
+      }
+
+      return 1;
+   }
+}
+
+int PNGAPI
+png_image_finish_read(png_imagep image, png_const_colorp background,
+    void *buffer, png_int_32 row_stride, void *colormap)
+{
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      /* Check for row_stride overflow.  This check is not performed on the
+       * original PNG format because it may not occur in the output PNG format
+       * and libpng deals with the issues of reading the original.
+       */
+      unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
+
+      /* The following checks just the 'row_stride' calculation to ensure it
+       * fits in a signed 32-bit value.  Because channels/components can be
+       * either 1 or 2 bytes in size the length of a row can still overflow 32
+       * bits; this is just to verify that the 'row_stride' argument can be
+       * represented.
+       */
+      if (image->width <= 0x7fffffffU/channels) /* no overflow */
+      {
+         png_uint_32 check;
+         png_uint_32 png_row_stride = image->width * channels;
+
+         if (row_stride == 0)
+            row_stride = (png_int_32)/*SAFE*/png_row_stride;
+
+         if (row_stride < 0)
+            check = (png_uint_32)(-row_stride);
+
+         else
+            check = (png_uint_32)row_stride;
+
+         /* This verifies 'check', the absolute value of the actual stride
+          * passed in and detects overflow in the application calculation (i.e.
+          * if the app did actually pass in a non-zero 'row_stride'.
+          */
+         if (image->opaque != NULL && buffer != NULL && check >= png_row_stride)
+         {
+            /* Now check for overflow of the image buffer calculation; this
+             * limits the whole image size to 32 bits for API compatibility with
+             * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
+             *
+             * The PNG_IMAGE_BUFFER_SIZE macro is:
+             *
+             *    (PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)*height*(row_stride))
+             *
+             * And the component size is always 1 or 2, so make sure that the
+             * number of *bytes* that the application is saying are available
+             * does actually fit into a 32-bit number.
+             *
+             * NOTE: this will be changed in 1.7 because PNG_IMAGE_BUFFER_SIZE
+             * will be changed to use png_alloc_size_t; bigger images can be
+             * accommodated on 64-bit systems.
+             */
+            if (image->height <=
+                0xffffffffU/PNG_IMAGE_PIXEL_COMPONENT_SIZE(image->format)/check)
+            {
+               if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 ||
+                  (image->colormap_entries > 0 && colormap != NULL))
+               {
+                  int result;
+                  png_image_read_control display;
+
+                  memset(&display, 0, (sizeof display));
+                  display.image = image;
+                  display.buffer = buffer;
+                  display.row_stride = row_stride;
+                  display.colormap = colormap;
+                  display.background = background;
+                  display.local_row = NULL;
+
+                  /* Choose the correct 'end' routine; for the color-map case
+                   * all the setup has already been done.
+                   */
+                  if ((image->format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+                     result =
+                         png_safe_execute(image,
+                             png_image_read_colormap, &display) &&
+                             png_safe_execute(image,
+                             png_image_read_colormapped, &display);
+
+                  else
+                     result =
+                        png_safe_execute(image,
+                            png_image_read_direct, &display);
+
+                  png_image_free(image);
+                  return result;
+               }
+
+               else
+                  return png_image_error(image,
+                      "png_image_finish_read[color-map]: no color-map");
+            }
+
+            else
+               return png_image_error(image,
+                   "png_image_finish_read: image too large");
+         }
+
+         else
+            return png_image_error(image,
+                "png_image_finish_read: invalid argument");
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_finish_read: row_stride too large");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_finish_read: damaged PNG_IMAGE_VERSION");
+
+   return 0;
+}
+
+#endif /* SIMPLIFIED_READ */
+#endif /* READ */
diff --git a/extern/libpng/pngrio.c b/extern/libpng/pngrio.c
new file mode 100644
index 0000000000..7946358101
--- /dev/null
+++ b/extern/libpng/pngrio.c
@@ -0,0 +1,120 @@
+
+/* pngrio.c - functions for data input
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all input.  Users who need
+ * special handling are expected to write a function that has the same
+ * arguments as this and performs a similar function, but that possibly
+ * has a different input method.  Note that you shouldn't change this
+ * function, but rather write a replacement function and then make
+ * libpng use it at run time with png_set_read_fn(...).
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Read the data from whatever input you are using.  The default routine
+ * reads from a file pointer.  Note that this routine sometimes gets called
+ * with very small lengths, so you should implement some kind of simple
+ * buffering if you are using unbuffered reads.  This should never be asked
+ * to read more than 64K on a 16-bit machine.
+ */
+void /* PRIVATE */
+png_read_data(png_structrp png_ptr, png_bytep data, size_t length)
+{
+   png_debug1(4, "reading %d bytes", (int)length);
+
+   if (png_ptr->read_data_fn != NULL)
+      (*(png_ptr->read_data_fn))(png_ptr, data, length);
+
+   else
+      png_error(png_ptr, "Call to NULL read function");
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+/* This is the function that does the actual reading of data.  If you are
+ * not reading from a standard C stream, you should create a replacement
+ * read_data function and use it at run time with png_set_read_fn(), rather
+ * than changing the library.
+ */
+void PNGCBAPI
+png_default_read_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check;
+
+   if (png_ptr == NULL)
+      return;
+
+   /* fread() returns 0 on error, so it is OK to store this in a size_t
+    * instead of an int, which is what fread() actually returns.
+    */
+   check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr));
+
+   if (check != length)
+      png_error(png_ptr, "Read Error");
+}
+#endif
+
+/* This function allows the application to supply a new input function
+ * for libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ *
+ * png_ptr      - pointer to a png input data structure
+ *
+ * io_ptr       - pointer to user supplied structure containing info about
+ *                the input functions.  May be NULL.
+ *
+ * read_data_fn - pointer to a new input function that takes as its
+ *                arguments a pointer to a png_struct, a pointer to
+ *                a location where input data can be stored, and a 32-bit
+ *                unsigned int that is the number of bytes to be read.
+ *                To exit and output any fatal error messages the new write
+ *                function should call png_error(png_ptr, "Error msg").
+ *                May be NULL, in which case libpng's default function will
+ *                be used.
+ */
+void PNGAPI
+png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr,
+    png_rw_ptr read_data_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->io_ptr = io_ptr;
+
+#ifdef PNG_STDIO_SUPPORTED
+   if (read_data_fn != NULL)
+      png_ptr->read_data_fn = read_data_fn;
+
+   else
+      png_ptr->read_data_fn = png_default_read_data;
+#else
+   png_ptr->read_data_fn = read_data_fn;
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+   /* It is an error to write to a read device */
+   if (png_ptr->write_data_fn != NULL)
+   {
+      png_ptr->write_data_fn = NULL;
+      png_warning(png_ptr,
+          "Can't set both read_data_fn and write_data_fn in the"
+          " same structure");
+   }
+#endif
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+   png_ptr->output_flush_fn = NULL;
+#endif
+}
+#endif /* READ */
diff --git a/extern/libpng/pngrtran.c b/extern/libpng/pngrtran.c
new file mode 100644
index 0000000000..9a8fad9f4a
--- /dev/null
+++ b/extern/libpng/pngrtran.c
@@ -0,0 +1,5044 @@
+
+/* pngrtran.c - transforms the data in a row for PNG readers
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file contains functions optionally called by an application
+ * in order to tell libpng how to handle data when reading a PNG.
+ * Transformations that are used in both reading and writing are
+ * in pngtrans.c.
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_ARM_NEON_IMPLEMENTATION
+#  if PNG_ARM_NEON_IMPLEMENTATION == 1
+#    define PNG_ARM_NEON_INTRINSICS_AVAILABLE
+#    if defined(_MSC_VER) && defined(_M_ARM64)
+#      include <arm64_neon.h>
+#    else
+#      include <arm_neon.h>
+#    endif
+#  endif
+#endif
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Set the action on getting a CRC error for an ancillary or critical chunk. */
+void PNGAPI
+png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
+{
+   png_debug(1, "in png_set_crc_action");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* Tell libpng how we react to CRC errors in critical chunks */
+   switch (crit_action)
+   {
+      case PNG_CRC_NO_CHANGE:                        /* Leave setting as is */
+         break;
+
+      case PNG_CRC_WARN_USE:                               /* Warn/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
+         break;
+
+      case PNG_CRC_QUIET_USE:                             /* Quiet/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
+                           PNG_FLAG_CRC_CRITICAL_IGNORE;
+         break;
+
+      case PNG_CRC_WARN_DISCARD:    /* Not a valid action for critical data */
+         png_warning(png_ptr,
+             "Can't discard critical data on CRC error");
+         /* FALLTHROUGH */
+      case PNG_CRC_ERROR_QUIT:                                /* Error/quit */
+
+      case PNG_CRC_DEFAULT:
+      default:
+         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+         break;
+   }
+
+   /* Tell libpng how we react to CRC errors in ancillary chunks */
+   switch (ancil_action)
+   {
+      case PNG_CRC_NO_CHANGE:                       /* Leave setting as is */
+         break;
+
+      case PNG_CRC_WARN_USE:                              /* Warn/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
+         break;
+
+      case PNG_CRC_QUIET_USE:                            /* Quiet/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
+                           PNG_FLAG_CRC_ANCILLARY_NOWARN;
+         break;
+
+      case PNG_CRC_ERROR_QUIT:                               /* Error/quit */
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
+         break;
+
+      case PNG_CRC_WARN_DISCARD:                      /* Warn/discard data */
+
+      case PNG_CRC_DEFAULT:
+      default:
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         break;
+   }
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Is it OK to set a transformation now?  Only if png_start_read_image or
+ * png_read_update_info have not been called.  It is not necessary for the IHDR
+ * to have been read in all cases; the need_IHDR parameter allows for this
+ * check too.
+ */
+static int
+png_rtran_ok(png_structrp png_ptr, int need_IHDR)
+{
+   if (png_ptr != NULL)
+   {
+      if ((png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
+         png_app_error(png_ptr,
+             "invalid after png_start_read_image or png_read_update_info");
+
+      else if (need_IHDR && (png_ptr->mode & PNG_HAVE_IHDR) == 0)
+         png_app_error(png_ptr, "invalid before the PNG header has been read");
+
+      else
+      {
+         /* Turn on failure to initialize correctly for all transforms. */
+         png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
+
+         return 1; /* Ok */
+      }
+   }
+
+   return 0; /* no png_error possible! */
+}
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* Handle alpha and tRNS via a background color */
+void PNGFAPI
+png_set_background_fixed(png_structrp png_ptr,
+    png_const_color_16p background_color, int background_gamma_code,
+    int need_expand, png_fixed_point background_gamma)
+{
+   png_debug(1, "in png_set_background_fixed");
+
+   if (png_rtran_ok(png_ptr, 0) == 0 || background_color == NULL)
+      return;
+
+   if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
+   {
+      png_warning(png_ptr, "Application must supply a known background gamma");
+      return;
+   }
+
+   png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA;
+   png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+   png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+   png_ptr->background = *background_color;
+   png_ptr->background_gamma = background_gamma;
+   png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
+   if (need_expand != 0)
+      png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
+   else
+      png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_background(png_structrp png_ptr,
+    png_const_color_16p background_color, int background_gamma_code,
+    int need_expand, double background_gamma)
+{
+   png_set_background_fixed(png_ptr, background_color, background_gamma_code,
+      need_expand, png_fixed(png_ptr, background_gamma, "png_set_background"));
+}
+#  endif /* FLOATING_POINT */
+#endif /* READ_BACKGROUND */
+
+/* Scale 16-bit depth files to 8-bit depth.  If both of these are set then the
+ * one that pngrtran does first (scale) happens.  This is necessary to allow the
+ * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
+ */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+void PNGAPI
+png_set_scale_16(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_scale_16");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_SCALE_16_TO_8;
+}
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+/* Chop 16-bit depth files to 8-bit depth */
+void PNGAPI
+png_set_strip_16(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_strip_16");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_16_TO_8;
+}
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+void PNGAPI
+png_set_strip_alpha(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_strip_alpha");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_STRIP_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
+static png_fixed_point
+translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma,
+    int is_screen)
+{
+   /* Check for flag values.  The main reason for having the old Mac value as a
+    * flag is that it is pretty near impossible to work out what the correct
+    * value is from Apple documentation - a working Mac system is needed to
+    * discover the value!
+    */
+   if (output_gamma == PNG_DEFAULT_sRGB ||
+      output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
+   {
+      /* If there is no sRGB support this just sets the gamma to the standard
+       * sRGB value.  (This is a side effect of using this function!)
+       */
+#     ifdef PNG_READ_sRGB_SUPPORTED
+         png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
+#     else
+         PNG_UNUSED(png_ptr)
+#     endif
+      if (is_screen != 0)
+         output_gamma = PNG_GAMMA_sRGB;
+      else
+         output_gamma = PNG_GAMMA_sRGB_INVERSE;
+   }
+
+   else if (output_gamma == PNG_GAMMA_MAC_18 ||
+      output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
+   {
+      if (is_screen != 0)
+         output_gamma = PNG_GAMMA_MAC_OLD;
+      else
+         output_gamma = PNG_GAMMA_MAC_INVERSE;
+   }
+
+   return output_gamma;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+static png_fixed_point
+convert_gamma_value(png_structrp png_ptr, double output_gamma)
+{
+   /* The following silently ignores cases where fixed point (times 100,000)
+    * gamma values are passed to the floating point API.  This is safe and it
+    * means the fixed point constants work just fine with the floating point
+    * API.  The alternative would just lead to undetected errors and spurious
+    * bug reports.  Negative values fail inside the _fixed API unless they
+    * correspond to the flag values.
+    */
+   if (output_gamma > 0 && output_gamma < 128)
+      output_gamma *= PNG_FP_1;
+
+   /* This preserves -1 and -2 exactly: */
+   output_gamma = floor(output_gamma + .5);
+
+   if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
+      png_fixed_error(png_ptr, "gamma value");
+
+   return (png_fixed_point)output_gamma;
+}
+#  endif
+#endif /* READ_ALPHA_MODE || READ_GAMMA */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+void PNGFAPI
+png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
+    png_fixed_point output_gamma)
+{
+   int compose = 0;
+   png_fixed_point file_gamma;
+
+   png_debug(1, "in png_set_alpha_mode");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
+
+   /* Validate the value to ensure it is in a reasonable range. The value
+    * is expected to be 1 or greater, but this range test allows for some
+    * viewing correction values.  The intent is to weed out users of this API
+    * who use the inverse of the gamma value accidentally!  Since some of these
+    * values are reasonable this may have to be changed:
+    *
+    * 1.6.x: changed from 0.07..3 to 0.01..100 (to accommodate the optimal 16-bit
+    * gamma of 36, and its reciprocal.)
+    */
+   if (output_gamma < 1000 || output_gamma > 10000000)
+      png_error(png_ptr, "output gamma out of expected range");
+
+   /* The default file gamma is the inverse of the output gamma; the output
+    * gamma may be changed below so get the file value first:
+    */
+   file_gamma = png_reciprocal(output_gamma);
+
+   /* There are really 8 possibilities here, composed of any combination
+    * of:
+    *
+    *    premultiply the color channels
+    *    do not encode non-opaque pixels
+    *    encode the alpha as well as the color channels
+    *
+    * The differences disappear if the input/output ('screen') gamma is 1.0,
+    * because then the encoding is a no-op and there is only the choice of
+    * premultiplying the color channels or not.
+    *
+    * png_set_alpha_mode and png_set_background interact because both use
+    * png_compose to do the work.  Calling both is only useful when
+    * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
+    * with a default gamma value.  Otherwise PNG_COMPOSE must not be set.
+    */
+   switch (mode)
+   {
+      case PNG_ALPHA_PNG:        /* default: png standard */
+         /* No compose, but it may be set by png_set_background! */
+         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+         break;
+
+      case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
+         compose = 1;
+         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+         /* The output is linear: */
+         output_gamma = PNG_FP_1;
+         break;
+
+      case PNG_ALPHA_OPTIMIZED:  /* associated, non-opaque pixels linear */
+         compose = 1;
+         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+         png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
+         /* output_gamma records the encoding of opaque pixels! */
+         break;
+
+      case PNG_ALPHA_BROKEN:     /* associated, non-linear, alpha encoded */
+         compose = 1;
+         png_ptr->transformations |= PNG_ENCODE_ALPHA;
+         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+         break;
+
+      default:
+         png_error(png_ptr, "invalid alpha mode");
+   }
+
+   /* Only set the default gamma if the file gamma has not been set (this has
+    * the side effect that the gamma in a second call to png_set_alpha_mode will
+    * be ignored.)
+    */
+   if (png_ptr->colorspace.gamma == 0)
+   {
+      png_ptr->colorspace.gamma = file_gamma;
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+   }
+
+   /* But always set the output gamma: */
+   png_ptr->screen_gamma = output_gamma;
+
+   /* Finally, if pre-multiplying, set the background fields to achieve the
+    * desired result.
+    */
+   if (compose != 0)
+   {
+      /* And obtain alpha pre-multiplication by composing on black: */
+      memset(&png_ptr->background, 0, (sizeof png_ptr->background));
+      png_ptr->background_gamma = png_ptr->colorspace.gamma; /* just in case */
+      png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
+      png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
+
+      if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+         png_error(png_ptr,
+             "conflicting calls to set alpha mode and background");
+
+      png_ptr->transformations |= PNG_COMPOSE;
+   }
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma)
+{
+   png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
+       output_gamma));
+}
+#  endif
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* Dither file to 8-bit.  Supply a palette, the current number
+ * of elements in the palette, the maximum number of elements
+ * allowed, and a histogram if possible.  If the current number
+ * of colors is greater than the maximum number, the palette will be
+ * modified to fit in the maximum number.  "full_quantize" indicates
+ * whether we need a quantizing cube set up for RGB images, or if we
+ * simply are reducing the number of colors in a paletted image.
+ */
+
+typedef struct png_dsort_struct
+{
+   struct png_dsort_struct * next;
+   png_byte left;
+   png_byte right;
+} png_dsort;
+typedef png_dsort *   png_dsortp;
+typedef png_dsort * * png_dsortpp;
+
+void PNGAPI
+png_set_quantize(png_structrp png_ptr, png_colorp palette,
+    int num_palette, int maximum_colors, png_const_uint_16p histogram,
+    int full_quantize)
+{
+   png_debug(1, "in png_set_quantize");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_QUANTIZE;
+
+   if (full_quantize == 0)
+   {
+      int i;
+
+      png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
+          (png_alloc_size_t)((png_uint_32)num_palette * (sizeof (png_byte))));
+      for (i = 0; i < num_palette; i++)
+         png_ptr->quantize_index[i] = (png_byte)i;
+   }
+
+   if (num_palette > maximum_colors)
+   {
+      if (histogram != NULL)
+      {
+         /* This is easy enough, just throw out the least used colors.
+          * Perhaps not the best solution, but good enough.
+          */
+
+         int i;
+
+         /* Initialize an array to sort colors */
+         png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
+             (png_alloc_size_t)((png_uint_32)num_palette * (sizeof (png_byte))));
+
+         /* Initialize the quantize_sort array */
+         for (i = 0; i < num_palette; i++)
+            png_ptr->quantize_sort[i] = (png_byte)i;
+
+         /* Find the least used palette entries by starting a
+          * bubble sort, and running it until we have sorted
+          * out enough colors.  Note that we don't care about
+          * sorting all the colors, just finding which are
+          * least used.
+          */
+
+         for (i = num_palette - 1; i >= maximum_colors; i--)
+         {
+            int done; /* To stop early if the list is pre-sorted */
+            int j;
+
+            done = 1;
+            for (j = 0; j < i; j++)
+            {
+               if (histogram[png_ptr->quantize_sort[j]]
+                   < histogram[png_ptr->quantize_sort[j + 1]])
+               {
+                  png_byte t;
+
+                  t = png_ptr->quantize_sort[j];
+                  png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
+                  png_ptr->quantize_sort[j + 1] = t;
+                  done = 0;
+               }
+            }
+
+            if (done != 0)
+               break;
+         }
+
+         /* Swap the palette around, and set up a table, if necessary */
+         if (full_quantize != 0)
+         {
+            int j = num_palette;
+
+            /* Put all the useful colors within the max, but don't
+             * move the others.
+             */
+            for (i = 0; i < maximum_colors; i++)
+            {
+               if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
+               {
+                  do
+                     j--;
+                  while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
+
+                  palette[i] = palette[j];
+               }
+            }
+         }
+         else
+         {
+            int j = num_palette;
+
+            /* Move all the used colors inside the max limit, and
+             * develop a translation table.
+             */
+            for (i = 0; i < maximum_colors; i++)
+            {
+               /* Only move the colors we need to */
+               if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
+               {
+                  png_color tmp_color;
+
+                  do
+                     j--;
+                  while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
+
+                  tmp_color = palette[j];
+                  palette[j] = palette[i];
+                  palette[i] = tmp_color;
+                  /* Indicate where the color went */
+                  png_ptr->quantize_index[j] = (png_byte)i;
+                  png_ptr->quantize_index[i] = (png_byte)j;
+               }
+            }
+
+            /* Find closest color for those colors we are not using */
+            for (i = 0; i < num_palette; i++)
+            {
+               if ((int)png_ptr->quantize_index[i] >= maximum_colors)
+               {
+                  int min_d, k, min_k, d_index;
+
+                  /* Find the closest color to one we threw out */
+                  d_index = png_ptr->quantize_index[i];
+                  min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
+                  for (k = 1, min_k = 0; k < maximum_colors; k++)
+                  {
+                     int d;
+
+                     d = PNG_COLOR_DIST(palette[d_index], palette[k]);
+
+                     if (d < min_d)
+                     {
+                        min_d = d;
+                        min_k = k;
+                     }
+                  }
+                  /* Point to closest color */
+                  png_ptr->quantize_index[i] = (png_byte)min_k;
+               }
+            }
+         }
+         png_free(png_ptr, png_ptr->quantize_sort);
+         png_ptr->quantize_sort = NULL;
+      }
+      else
+      {
+         /* This is much harder to do simply (and quickly).  Perhaps
+          * we need to go through a median cut routine, but those
+          * don't always behave themselves with only a few colors
+          * as input.  So we will just find the closest two colors,
+          * and throw out one of them (chosen somewhat randomly).
+          * [We don't understand this at all, so if someone wants to
+          *  work on improving it, be our guest - AED, GRP]
+          */
+         int i;
+         int max_d;
+         int num_new_palette;
+         png_dsortp t;
+         png_dsortpp hash;
+
+         t = NULL;
+
+         /* Initialize palette index arrays */
+         png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
+             (png_alloc_size_t)((png_uint_32)num_palette *
+             (sizeof (png_byte))));
+         png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
+             (png_alloc_size_t)((png_uint_32)num_palette *
+             (sizeof (png_byte))));
+
+         /* Initialize the sort array */
+         for (i = 0; i < num_palette; i++)
+         {
+            png_ptr->index_to_palette[i] = (png_byte)i;
+            png_ptr->palette_to_index[i] = (png_byte)i;
+         }
+
+         hash = (png_dsortpp)png_calloc(png_ptr, (png_alloc_size_t)(769 *
+             (sizeof (png_dsortp))));
+
+         num_new_palette = num_palette;
+
+         /* Initial wild guess at how far apart the farthest pixel
+          * pair we will be eliminating will be.  Larger
+          * numbers mean more areas will be allocated, Smaller
+          * numbers run the risk of not saving enough data, and
+          * having to do this all over again.
+          *
+          * I have not done extensive checking on this number.
+          */
+         max_d = 96;
+
+         while (num_new_palette > maximum_colors)
+         {
+            for (i = 0; i < num_new_palette - 1; i++)
+            {
+               int j;
+
+               for (j = i + 1; j < num_new_palette; j++)
+               {
+                  int d;
+
+                  d = PNG_COLOR_DIST(palette[i], palette[j]);
+
+                  if (d <= max_d)
+                  {
+
+                     t = (png_dsortp)png_malloc_warn(png_ptr,
+                         (png_alloc_size_t)(sizeof (png_dsort)));
+
+                     if (t == NULL)
+                         break;
+
+                     t->next = hash[d];
+                     t->left = (png_byte)i;
+                     t->right = (png_byte)j;
+                     hash[d] = t;
+                  }
+               }
+               if (t == NULL)
+                  break;
+            }
+
+            if (t != NULL)
+            for (i = 0; i <= max_d; i++)
+            {
+               if (hash[i] != NULL)
+               {
+                  png_dsortp p;
+
+                  for (p = hash[i]; p; p = p->next)
+                  {
+                     if ((int)png_ptr->index_to_palette[p->left]
+                         < num_new_palette &&
+                         (int)png_ptr->index_to_palette[p->right]
+                         < num_new_palette)
+                     {
+                        int j, next_j;
+
+                        if (num_new_palette & 0x01)
+                        {
+                           j = p->left;
+                           next_j = p->right;
+                        }
+                        else
+                        {
+                           j = p->right;
+                           next_j = p->left;
+                        }
+
+                        num_new_palette--;
+                        palette[png_ptr->index_to_palette[j]]
+                            = palette[num_new_palette];
+                        if (full_quantize == 0)
+                        {
+                           int k;
+
+                           for (k = 0; k < num_palette; k++)
+                           {
+                              if (png_ptr->quantize_index[k] ==
+                                  png_ptr->index_to_palette[j])
+                                 png_ptr->quantize_index[k] =
+                                     png_ptr->index_to_palette[next_j];
+
+                              if ((int)png_ptr->quantize_index[k] ==
+                                  num_new_palette)
+                                 png_ptr->quantize_index[k] =
+                                     png_ptr->index_to_palette[j];
+                           }
+                        }
+
+                        png_ptr->index_to_palette[png_ptr->palette_to_index
+                            [num_new_palette]] = png_ptr->index_to_palette[j];
+
+                        png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
+                            = png_ptr->palette_to_index[num_new_palette];
+
+                        png_ptr->index_to_palette[j] =
+                            (png_byte)num_new_palette;
+
+                        png_ptr->palette_to_index[num_new_palette] =
+                            (png_byte)j;
+                     }
+                     if (num_new_palette <= maximum_colors)
+                        break;
+                  }
+                  if (num_new_palette <= maximum_colors)
+                     break;
+               }
+            }
+
+            for (i = 0; i < 769; i++)
+            {
+               if (hash[i] != NULL)
+               {
+                  png_dsortp p = hash[i];
+                  while (p)
+                  {
+                     t = p->next;
+                     png_free(png_ptr, p);
+                     p = t;
+                  }
+               }
+               hash[i] = 0;
+            }
+            max_d += 96;
+         }
+         png_free(png_ptr, hash);
+         png_free(png_ptr, png_ptr->palette_to_index);
+         png_free(png_ptr, png_ptr->index_to_palette);
+         png_ptr->palette_to_index = NULL;
+         png_ptr->index_to_palette = NULL;
+      }
+      num_palette = maximum_colors;
+   }
+   if (png_ptr->palette == NULL)
+   {
+      png_ptr->palette = palette;
+   }
+   png_ptr->num_palette = (png_uint_16)num_palette;
+
+   if (full_quantize != 0)
+   {
+      int i;
+      png_bytep distance;
+      int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
+          PNG_QUANTIZE_BLUE_BITS;
+      int num_red = (1 << PNG_QUANTIZE_RED_BITS);
+      int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
+      int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);
+      size_t num_entries = ((size_t)1 << total_bits);
+
+      png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr,
+          (png_alloc_size_t)(num_entries * (sizeof (png_byte))));
+
+      distance = (png_bytep)png_malloc(png_ptr, (png_alloc_size_t)(num_entries *
+          (sizeof (png_byte))));
+
+      memset(distance, 0xff, num_entries * (sizeof (png_byte)));
+
+      for (i = 0; i < num_palette; i++)
+      {
+         int ir, ig, ib;
+         int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
+         int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
+         int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS));
+
+         for (ir = 0; ir < num_red; ir++)
+         {
+            /* int dr = abs(ir - r); */
+            int dr = ((ir > r) ? ir - r : r - ir);
+            int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS +
+                PNG_QUANTIZE_GREEN_BITS));
+
+            for (ig = 0; ig < num_green; ig++)
+            {
+               /* int dg = abs(ig - g); */
+               int dg = ((ig > g) ? ig - g : g - ig);
+               int dt = dr + dg;
+               int dm = ((dr > dg) ? dr : dg);
+               int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS);
+
+               for (ib = 0; ib < num_blue; ib++)
+               {
+                  int d_index = index_g | ib;
+                  /* int db = abs(ib - b); */
+                  int db = ((ib > b) ? ib - b : b - ib);
+                  int dmax = ((dm > db) ? dm : db);
+                  int d = dmax + dt + db;
+
+                  if (d < (int)distance[d_index])
+                  {
+                     distance[d_index] = (png_byte)d;
+                     png_ptr->palette_lookup[d_index] = (png_byte)i;
+                  }
+               }
+            }
+         }
+      }
+
+      png_free(png_ptr, distance);
+   }
+}
+#endif /* READ_QUANTIZE */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+void PNGFAPI
+png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
+    png_fixed_point file_gamma)
+{
+   png_debug(1, "in png_set_gamma_fixed");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   /* New in libpng-1.5.4 - reserve particular negative values as flags. */
+   scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
+   file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
+
+   /* Checking the gamma values for being >0 was added in 1.5.4 along with the
+    * premultiplied alpha support; this actually hides an undocumented feature
+    * of the previous implementation which allowed gamma processing to be
+    * disabled in background handling.  There is no evidence (so far) that this
+    * was being used; however, png_set_background itself accepted and must still
+    * accept '0' for the gamma value it takes, because it isn't always used.
+    *
+    * Since this is an API change (albeit a very minor one that removes an
+    * undocumented API feature) the following checks were only enabled in
+    * libpng-1.6.0.
+    */
+   if (file_gamma <= 0)
+      png_error(png_ptr, "invalid file gamma in png_set_gamma");
+
+   if (scrn_gamma <= 0)
+      png_error(png_ptr, "invalid screen gamma in png_set_gamma");
+
+   /* Set the gamma values unconditionally - this overrides the value in the PNG
+    * file if a gAMA chunk was present.  png_set_alpha_mode provides a
+    * different, easier, way to default the file gamma.
+    */
+   png_ptr->colorspace.gamma = file_gamma;
+   png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+   png_ptr->screen_gamma = scrn_gamma;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_gamma(png_structrp png_ptr, double scrn_gamma, double file_gamma)
+{
+   png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
+       convert_gamma_value(png_ptr, file_gamma));
+}
+#  endif /* FLOATING_POINT */
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expand paletted images to RGB, expand grayscale images of
+ * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
+ * to alpha channels.
+ */
+void PNGAPI
+png_set_expand(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_expand");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+
+/* GRR 19990627:  the following three functions currently are identical
+ *  to png_set_expand().  However, it is entirely reasonable that someone
+ *  might wish to expand an indexed image to RGB but *not* expand a single,
+ *  fully transparent palette entry to a full alpha channel--perhaps instead
+ *  convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
+ *  the transparent color with a particular RGB value, or drop tRNS entirely.
+ *  IOW, a future version of the library may make the transformations flag
+ *  a bit more fine-grained, with separate bits for each of these three
+ *  functions.
+ *
+ *  More to the point, these functions make it obvious what libpng will be
+ *  doing, whereas "expand" can (and does) mean any number of things.
+ *
+ *  GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
+ *  to expand only the sample depth but not to expand the tRNS to alpha
+ *  and its name was changed to png_set_expand_gray_1_2_4_to_8().
+ */
+
+/* Expand paletted images to RGB. */
+void PNGAPI
+png_set_palette_to_rgb(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_palette_to_rgb");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+
+/* Expand grayscale images of less than 8-bit depth to 8 bits. */
+void PNGAPI
+png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_EXPAND;
+}
+
+/* Expand tRNS chunks to alpha channels. */
+void PNGAPI
+png_set_tRNS_to_alpha(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_tRNS_to_alpha");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+#endif /* READ_EXPAND */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
+ * it may not work correctly.)
+ */
+void PNGAPI
+png_set_expand_16(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_expand_16");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+void PNGAPI
+png_set_gray_to_rgb(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_gray_to_rgb");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   /* Because rgb must be 8 bits or more: */
+   png_set_expand_gray_1_2_4_to_8(png_ptr);
+   png_ptr->transformations |= PNG_GRAY_TO_RGB;
+}
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+void PNGFAPI
+png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
+    png_fixed_point red, png_fixed_point green)
+{
+   png_debug(1, "in png_set_rgb_to_gray");
+
+   /* Need the IHDR here because of the check on color_type below. */
+   /* TODO: fix this */
+   if (png_rtran_ok(png_ptr, 1) == 0)
+      return;
+
+   switch (error_action)
+   {
+      case PNG_ERROR_ACTION_NONE:
+         png_ptr->transformations |= PNG_RGB_TO_GRAY;
+         break;
+
+      case PNG_ERROR_ACTION_WARN:
+         png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
+         break;
+
+      case PNG_ERROR_ACTION_ERROR:
+         png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
+         break;
+
+      default:
+         png_error(png_ptr, "invalid error action to rgb_to_gray");
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#ifdef PNG_READ_EXPAND_SUPPORTED
+      png_ptr->transformations |= PNG_EXPAND;
+#else
+   {
+      /* Make this an error in 1.6 because otherwise the application may assume
+       * that it just worked and get a memory overwrite.
+       */
+      png_error(png_ptr,
+          "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
+
+      /* png_ptr->transformations &= ~PNG_RGB_TO_GRAY; */
+   }
+#endif
+   {
+      if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
+      {
+         png_uint_16 red_int, green_int;
+
+         /* NOTE: this calculation does not round, but this behavior is retained
+          * for consistency; the inaccuracy is very small.  The code here always
+          * overwrites the coefficients, regardless of whether they have been
+          * defaulted or set already.
+          */
+         red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
+         green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
+
+         png_ptr->rgb_to_gray_red_coeff   = red_int;
+         png_ptr->rgb_to_gray_green_coeff = green_int;
+         png_ptr->rgb_to_gray_coefficients_set = 1;
+      }
+
+      else
+      {
+         if (red >= 0 && green >= 0)
+            png_app_warning(png_ptr,
+                "ignoring out of range rgb_to_gray coefficients");
+
+         /* Use the defaults, from the cHRM chunk if set, else the historical
+          * values which are close to the sRGB/HDTV/ITU-Rec 709 values.  See
+          * png_do_rgb_to_gray for more discussion of the values.  In this case
+          * the coefficients are not marked as 'set' and are not overwritten if
+          * something has already provided a default.
+          */
+         if (png_ptr->rgb_to_gray_red_coeff == 0 &&
+             png_ptr->rgb_to_gray_green_coeff == 0)
+         {
+            png_ptr->rgb_to_gray_red_coeff   = 6968;
+            png_ptr->rgb_to_gray_green_coeff = 23434;
+            /* png_ptr->rgb_to_gray_blue_coeff  = 2366; */
+         }
+      }
+   }
+}
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+/* Convert a RGB image to a grayscale of the same width.  This allows us,
+ * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
+ */
+
+void PNGAPI
+png_set_rgb_to_gray(png_structrp png_ptr, int error_action, double red,
+    double green)
+{
+   png_set_rgb_to_gray_fixed(png_ptr, error_action,
+       png_fixed(png_ptr, red, "rgb to gray red coefficient"),
+      png_fixed(png_ptr, green, "rgb to gray green coefficient"));
+}
+#endif /* FLOATING POINT */
+
+#endif /* RGB_TO_GRAY */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+void PNGAPI
+png_set_read_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
+    read_user_transform_fn)
+{
+   png_debug(1, "in png_set_read_user_transform_fn");
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   png_ptr->transformations |= PNG_USER_TRANSFORM;
+   png_ptr->read_user_transform_fn = read_user_transform_fn;
+#endif
+}
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* In the case of gamma transformations only do transformations on images where
+ * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
+ * slows things down slightly, and also needlessly introduces small errors.
+ */
+static int /* PRIVATE */
+png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
+{
+   /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
+    * correction as a difference of the overall transform from 1.0
+    *
+    * We want to compare the threshold with s*f - 1, if we get
+    * overflow here it is because of wacky gamma values so we
+    * turn on processing anyway.
+    */
+   png_fixed_point gtest;
+   return !png_muldiv(&gtest, screen_gamma, file_gamma, PNG_FP_1) ||
+       png_gamma_significant(gtest);
+}
+#endif
+
+/* Initialize everything needed for the read.  This includes modifying
+ * the palette.
+ */
+
+/* For the moment 'png_init_palette_transformations' and
+ * 'png_init_rgb_transformations' only do some flag canceling optimizations.
+ * The intent is that these two routines should have palette or rgb operations
+ * extracted from 'png_init_read_transformations'.
+ */
+static void /* PRIVATE */
+png_init_palette_transformations(png_structrp png_ptr)
+{
+   /* Called to handle the (input) palette case.  In png_do_read_transformations
+    * the first step is to expand the palette if requested, so this code must
+    * take care to only make changes that are invariant with respect to the
+    * palette expansion, or only do them if there is no expansion.
+    *
+    * STRIP_ALPHA has already been handled in the caller (by setting num_trans
+    * to 0.)
+    */
+   int input_has_alpha = 0;
+   int input_has_transparency = 0;
+
+   if (png_ptr->num_trans > 0)
+   {
+      int i;
+
+      /* Ignore if all the entries are opaque (unlikely!) */
+      for (i=0; i<png_ptr->num_trans; ++i)
+      {
+         if (png_ptr->trans_alpha[i] == 255)
+            continue;
+         else if (png_ptr->trans_alpha[i] == 0)
+            input_has_transparency = 1;
+         else
+         {
+            input_has_transparency = 1;
+            input_has_alpha = 1;
+            break;
+         }
+      }
+   }
+
+   /* If no alpha we can optimize. */
+   if (input_has_alpha == 0)
+   {
+      /* Any alpha means background and associative alpha processing is
+       * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
+       * and ENCODE_ALPHA are irrelevant.
+       */
+      png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+      if (input_has_transparency == 0)
+         png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
+   }
+
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* png_set_background handling - deals with the complexity of whether the
+    * background color is in the file format or the screen format in the case
+    * where an 'expand' will happen.
+    */
+
+   /* The following code cannot be entered in the alpha pre-multiplication case
+    * because PNG_BACKGROUND_EXPAND is cancelled below.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) != 0)
+   {
+      {
+         png_ptr->background.red   =
+             png_ptr->palette[png_ptr->background.index].red;
+         png_ptr->background.green =
+             png_ptr->palette[png_ptr->background.index].green;
+         png_ptr->background.blue  =
+             png_ptr->palette[png_ptr->background.index].blue;
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+         if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+         {
+            if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
+            {
+               /* Invert the alpha channel (in tRNS) unless the pixels are
+                * going to be expanded, in which case leave it for later
+                */
+               int i, istop = png_ptr->num_trans;
+
+               for (i = 0; i < istop; i++)
+                  png_ptr->trans_alpha[i] =
+                      (png_byte)(255 - png_ptr->trans_alpha[i]);
+            }
+         }
+#endif /* READ_INVERT_ALPHA */
+      }
+   } /* background expand and (therefore) no alpha association. */
+#endif /* READ_EXPAND && READ_BACKGROUND */
+}
+
+static void /* PRIVATE */
+png_init_rgb_transformations(png_structrp png_ptr)
+{
+   /* Added to libpng-1.5.4: check the color type to determine whether there
+    * is any alpha or transparency in the image and simply cancel the
+    * background and alpha mode stuff if there isn't.
+    */
+   int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
+   int input_has_transparency = png_ptr->num_trans > 0;
+
+   /* If no alpha we can optimize. */
+   if (input_has_alpha == 0)
+   {
+      /* Any alpha means background and associative alpha processing is
+       * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
+       * and ENCODE_ALPHA are irrelevant.
+       */
+#     ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+#     endif
+
+      if (input_has_transparency == 0)
+         png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
+   }
+
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* png_set_background handling - deals with the complexity of whether the
+    * background color is in the file format or the screen format in the case
+    * where an 'expand' will happen.
+    */
+
+   /* The following code cannot be entered in the alpha pre-multiplication case
+    * because PNG_BACKGROUND_EXPAND is cancelled below.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) != 0 &&
+       (png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+       /* i.e., GRAY or GRAY_ALPHA */
+   {
+      {
+         /* Expand background and tRNS chunks */
+         int gray = png_ptr->background.gray;
+         int trans_gray = png_ptr->trans_color.gray;
+
+         switch (png_ptr->bit_depth)
+         {
+            case 1:
+               gray *= 0xff;
+               trans_gray *= 0xff;
+               break;
+
+            case 2:
+               gray *= 0x55;
+               trans_gray *= 0x55;
+               break;
+
+            case 4:
+               gray *= 0x11;
+               trans_gray *= 0x11;
+               break;
+
+            default:
+
+            case 8:
+               /* FALLTHROUGH */ /*  (Already 8 bits) */
+
+            case 16:
+               /* Already a full 16 bits */
+               break;
+         }
+
+         png_ptr->background.red = png_ptr->background.green =
+            png_ptr->background.blue = (png_uint_16)gray;
+
+         if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
+         {
+            png_ptr->trans_color.red = png_ptr->trans_color.green =
+               png_ptr->trans_color.blue = (png_uint_16)trans_gray;
+         }
+      }
+   } /* background expand and (therefore) no alpha association. */
+#endif /* READ_EXPAND && READ_BACKGROUND */
+}
+
+void /* PRIVATE */
+png_init_read_transformations(png_structrp png_ptr)
+{
+   png_debug(1, "in png_init_read_transformations");
+
+   /* This internal function is called from png_read_start_row in pngrutil.c
+    * and it is called before the 'rowbytes' calculation is done, so the code
+    * in here can change or update the transformations flags.
+    *
+    * First do updates that do not depend on the details of the PNG image data
+    * being processed.
+    */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
+    * png_set_alpha_mode and this is another source for a default file gamma so
+    * the test needs to be performed later - here.  In addition prior to 1.5.4
+    * the tests were repeated for the PALETTE color type here - this is no
+    * longer necessary (and doesn't seem to have been necessary before.)
+    */
+   {
+      /* The following temporary indicates if overall gamma correction is
+       * required.
+       */
+      int gamma_correction = 0;
+
+      if (png_ptr->colorspace.gamma != 0) /* has been set */
+      {
+         if (png_ptr->screen_gamma != 0) /* screen set too */
+            gamma_correction = png_gamma_threshold(png_ptr->colorspace.gamma,
+                png_ptr->screen_gamma);
+
+         else
+            /* Assume the output matches the input; a long time default behavior
+             * of libpng, although the standard has nothing to say about this.
+             */
+            png_ptr->screen_gamma = png_reciprocal(png_ptr->colorspace.gamma);
+      }
+
+      else if (png_ptr->screen_gamma != 0)
+         /* The converse - assume the file matches the screen, note that this
+          * perhaps undesirable default can (from 1.5.4) be changed by calling
+          * png_set_alpha_mode (even if the alpha handling mode isn't required
+          * or isn't changed from the default.)
+          */
+         png_ptr->colorspace.gamma = png_reciprocal(png_ptr->screen_gamma);
+
+      else /* neither are set */
+         /* Just in case the following prevents any processing - file and screen
+          * are both assumed to be linear and there is no way to introduce a
+          * third gamma value other than png_set_background with 'UNIQUE', and,
+          * prior to 1.5.4
+          */
+         png_ptr->screen_gamma = png_ptr->colorspace.gamma = PNG_FP_1;
+
+      /* We have a gamma value now. */
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+
+      /* Now turn the gamma transformation on or off as appropriate.  Notice
+       * that PNG_GAMMA just refers to the file->screen correction.  Alpha
+       * composition may independently cause gamma correction because it needs
+       * linear data (e.g. if the file has a gAMA chunk but the screen gamma
+       * hasn't been specified.)  In any case this flag may get turned off in
+       * the code immediately below if the transform can be handled outside the
+       * row loop.
+       */
+      if (gamma_correction != 0)
+         png_ptr->transformations |= PNG_GAMMA;
+
+      else
+         png_ptr->transformations &= ~PNG_GAMMA;
+   }
+#endif
+
+   /* Certain transformations have the effect of preventing other
+    * transformations that happen afterward in png_do_read_transformations;
+    * resolve the interdependencies here.  From the code of
+    * png_do_read_transformations the order is:
+    *
+    *  1) PNG_EXPAND (including PNG_EXPAND_tRNS)
+    *  2) PNG_STRIP_ALPHA (if no compose)
+    *  3) PNG_RGB_TO_GRAY
+    *  4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
+    *  5) PNG_COMPOSE
+    *  6) PNG_GAMMA
+    *  7) PNG_STRIP_ALPHA (if compose)
+    *  8) PNG_ENCODE_ALPHA
+    *  9) PNG_SCALE_16_TO_8
+    * 10) PNG_16_TO_8
+    * 11) PNG_QUANTIZE (converts to palette)
+    * 12) PNG_EXPAND_16
+    * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
+    * 14) PNG_INVERT_MONO
+    * 15) PNG_INVERT_ALPHA
+    * 16) PNG_SHIFT
+    * 17) PNG_PACK
+    * 18) PNG_BGR
+    * 19) PNG_PACKSWAP
+    * 20) PNG_FILLER (includes PNG_ADD_ALPHA)
+    * 21) PNG_SWAP_ALPHA
+    * 22) PNG_SWAP_BYTES
+    * 23) PNG_USER_TRANSFORM [must be last]
+    */
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) == 0)
+   {
+      /* Stripping the alpha channel happens immediately after the 'expand'
+       * transformations, before all other transformation, so it cancels out
+       * the alpha handling.  It has the side effect negating the effect of
+       * PNG_EXPAND_tRNS too:
+       */
+      png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
+         PNG_EXPAND_tRNS);
+      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+      /* Kill the tRNS chunk itself too.  Prior to 1.5.4 this did not happen
+       * so transparency information would remain just so long as it wasn't
+       * expanded.  This produces unexpected API changes if the set of things
+       * that do PNG_EXPAND_tRNS changes (perfectly possible given the
+       * documentation - which says ask for what you want, accept what you
+       * get.)  This makes the behavior consistent from 1.5.4:
+       */
+      png_ptr->num_trans = 0;
+   }
+#endif /* STRIP_ALPHA supported, no COMPOSE */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+   /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
+    * settings will have no effect.
+    */
+   if (png_gamma_significant(png_ptr->screen_gamma) == 0)
+   {
+      png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+   }
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   /* Make sure the coefficients for the rgb to gray conversion are set
+    * appropriately.
+    */
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+      png_colorspace_set_rgb_coefficients(png_ptr);
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* Detect gray background and attempt to enable optimization for
+    * gray --> RGB case.
+    *
+    * Note:  if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+    * RGB_ALPHA (in which case need_expand is superfluous anyway), the
+    * background color might actually be gray yet not be flagged as such.
+    * This is not a problem for the current code, which uses
+    * PNG_BACKGROUND_IS_GRAY only to decide when to do the
+    * png_do_gray_to_rgb() transformation.
+    *
+    * TODO: this code needs to be revised to avoid the complexity and
+    * interdependencies.  The color type of the background should be recorded in
+    * png_set_background, along with the bit depth, then the code has a record
+    * of exactly what color space the background is currently in.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0)
+   {
+      /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
+       * the file was grayscale the background value is gray.
+       */
+      if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+         png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+   }
+
+   else if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+   {
+      /* PNG_COMPOSE: png_set_background was called with need_expand false,
+       * so the color is in the color space of the output or png_set_alpha_mode
+       * was called and the color is black.  Ignore RGB_TO_GRAY because that
+       * happens before GRAY_TO_RGB.
+       */
+      if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
+      {
+         if (png_ptr->background.red == png_ptr->background.green &&
+             png_ptr->background.red == png_ptr->background.blue)
+         {
+            png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+            png_ptr->background.gray = png_ptr->background.red;
+         }
+      }
+   }
+#endif /* READ_EXPAND && READ_BACKGROUND */
+#endif /* READ_GRAY_TO_RGB */
+
+   /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
+    * can be performed directly on the palette, and some (such as rgb to gray)
+    * can be optimized inside the palette.  This is particularly true of the
+    * composite (background and alpha) stuff, which can be pretty much all done
+    * in the palette even if the result is expanded to RGB or gray afterward.
+    *
+    * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
+    * earlier and the palette stuff is actually handled on the first row.  This
+    * leads to the reported bug that the palette returned by png_get_PLTE is not
+    * updated.
+    */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      png_init_palette_transformations(png_ptr);
+
+   else
+      png_init_rgb_transformations(png_ptr);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+   defined(PNG_READ_EXPAND_16_SUPPORTED)
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+       png_ptr->bit_depth != 16)
+   {
+      /* TODO: fix this.  Because the expand_16 operation is after the compose
+       * handling the background color must be 8, not 16, bits deep, but the
+       * application will supply a 16-bit value so reduce it here.
+       *
+       * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
+       * present, so that case is ok (until do_expand_16 is moved.)
+       *
+       * NOTE: this discards the low 16 bits of the user supplied background
+       * color, but until expand_16 works properly there is no choice!
+       */
+#     define CHOP(x) (x)=((png_uint_16)PNG_DIV257(x))
+      CHOP(png_ptr->background.red);
+      CHOP(png_ptr->background.green);
+      CHOP(png_ptr->background.blue);
+      CHOP(png_ptr->background.gray);
+#     undef CHOP
+   }
+#endif /* READ_BACKGROUND && READ_EXPAND_16 */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+   (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
+   defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
+   if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+       png_ptr->bit_depth == 16)
+   {
+      /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
+       * component this will also happen after PNG_COMPOSE and so the background
+       * color must be pre-expanded here.
+       *
+       * TODO: fix this too.
+       */
+      png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
+      png_ptr->background.green =
+         (png_uint_16)(png_ptr->background.green * 257);
+      png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
+      png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
+   }
+#endif
+
+   /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
+    * background support (see the comments in scripts/pnglibconf.dfa), this
+    * allows pre-multiplication of the alpha channel to be implemented as
+    * compositing on black.  This is probably sub-optimal and has been done in
+    * 1.5.4 betas simply to enable external critique and testing (i.e. to
+    * implement the new API quickly, without lots of internal changes.)
+    */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+#  ifdef PNG_READ_BACKGROUND_SUPPORTED
+      /* Includes ALPHA_MODE */
+      png_ptr->background_1 = png_ptr->background;
+#  endif
+
+   /* This needs to change - in the palette image case a whole set of tables are
+    * built when it would be quicker to just calculate the correct value for
+    * each palette entry directly.  Also, the test is too tricky - why check
+    * PNG_RGB_TO_GRAY if PNG_GAMMA is not set?  The answer seems to be that
+    * PNG_GAMMA is cancelled even if the gamma is known?  The test excludes the
+    * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
+    * the gamma tables will not be built even if composition is required on a
+    * gamma encoded value.
+    *
+    * In 1.5.4 this is addressed below by an additional check on the individual
+    * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
+    * tables.
+    */
+   if ((png_ptr->transformations & PNG_GAMMA) != 0 ||
+       ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 &&
+        (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+         png_gamma_significant(png_ptr->screen_gamma) != 0)) ||
+        ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+         (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+          png_gamma_significant(png_ptr->screen_gamma) != 0
+#  ifdef PNG_READ_BACKGROUND_SUPPORTED
+         || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE &&
+           png_gamma_significant(png_ptr->background_gamma) != 0)
+#  endif
+        )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+       png_gamma_significant(png_ptr->screen_gamma) != 0))
+   {
+      png_build_gamma_table(png_ptr, png_ptr->bit_depth);
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+      if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+      {
+         /* Issue a warning about this combination: because RGB_TO_GRAY is
+          * optimized to do the gamma transform if present yet do_background has
+          * to do the same thing if both options are set a
+          * double-gamma-correction happens.  This is true in all versions of
+          * libpng to date.
+          */
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+            png_warning(png_ptr,
+                "libpng does not support gamma+background+rgb_to_gray");
+
+         if ((png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) != 0)
+         {
+            /* We don't get to here unless there is a tRNS chunk with non-opaque
+             * entries - see the checking code at the start of this function.
+             */
+            png_color back, back_1;
+            png_colorp palette = png_ptr->palette;
+            int num_palette = png_ptr->num_palette;
+            int i;
+            if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
+            {
+
+               back.red = png_ptr->gamma_table[png_ptr->background.red];
+               back.green = png_ptr->gamma_table[png_ptr->background.green];
+               back.blue = png_ptr->gamma_table[png_ptr->background.blue];
+
+               back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
+               back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
+               back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
+            }
+            else
+            {
+               png_fixed_point g, gs;
+
+               switch (png_ptr->background_gamma_type)
+               {
+                  case PNG_BACKGROUND_GAMMA_SCREEN:
+                     g = (png_ptr->screen_gamma);
+                     gs = PNG_FP_1;
+                     break;
+
+                  case PNG_BACKGROUND_GAMMA_FILE:
+                     g = png_reciprocal(png_ptr->colorspace.gamma);
+                     gs = png_reciprocal2(png_ptr->colorspace.gamma,
+                         png_ptr->screen_gamma);
+                     break;
+
+                  case PNG_BACKGROUND_GAMMA_UNIQUE:
+                     g = png_reciprocal(png_ptr->background_gamma);
+                     gs = png_reciprocal2(png_ptr->background_gamma,
+                         png_ptr->screen_gamma);
+                     break;
+                  default:
+                     g = PNG_FP_1;    /* back_1 */
+                     gs = PNG_FP_1;   /* back */
+                     break;
+               }
+
+               if (png_gamma_significant(gs) != 0)
+               {
+                  back.red = png_gamma_8bit_correct(png_ptr->background.red,
+                      gs);
+                  back.green = png_gamma_8bit_correct(png_ptr->background.green,
+                      gs);
+                  back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+                      gs);
+               }
+
+               else
+               {
+                  back.red   = (png_byte)png_ptr->background.red;
+                  back.green = (png_byte)png_ptr->background.green;
+                  back.blue  = (png_byte)png_ptr->background.blue;
+               }
+
+               if (png_gamma_significant(g) != 0)
+               {
+                  back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
+                      g);
+                  back_1.green = png_gamma_8bit_correct(
+                      png_ptr->background.green, g);
+                  back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+                      g);
+               }
+
+               else
+               {
+                  back_1.red   = (png_byte)png_ptr->background.red;
+                  back_1.green = (png_byte)png_ptr->background.green;
+                  back_1.blue  = (png_byte)png_ptr->background.blue;
+               }
+            }
+
+            for (i = 0; i < num_palette; i++)
+            {
+               if (i < (int)png_ptr->num_trans &&
+                   png_ptr->trans_alpha[i] != 0xff)
+               {
+                  if (png_ptr->trans_alpha[i] == 0)
+                  {
+                     palette[i] = back;
+                  }
+                  else /* if (png_ptr->trans_alpha[i] != 0xff) */
+                  {
+                     png_byte v, w;
+
+                     v = png_ptr->gamma_to_1[palette[i].red];
+                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.red);
+                     palette[i].red = png_ptr->gamma_from_1[w];
+
+                     v = png_ptr->gamma_to_1[palette[i].green];
+                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.green);
+                     palette[i].green = png_ptr->gamma_from_1[w];
+
+                     v = png_ptr->gamma_to_1[palette[i].blue];
+                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue);
+                     palette[i].blue = png_ptr->gamma_from_1[w];
+                  }
+               }
+               else
+               {
+                  palette[i].red = png_ptr->gamma_table[palette[i].red];
+                  palette[i].green = png_ptr->gamma_table[palette[i].green];
+                  palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+               }
+            }
+
+            /* Prevent the transformations being done again.
+             *
+             * NOTE: this is highly dubious; it removes the transformations in
+             * place.  This seems inconsistent with the general treatment of the
+             * transformations elsewhere.
+             */
+            png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
+         } /* color_type == PNG_COLOR_TYPE_PALETTE */
+
+         /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
+         else /* color_type != PNG_COLOR_TYPE_PALETTE */
+         {
+            int gs_sig, g_sig;
+            png_fixed_point g = PNG_FP_1;  /* Correction to linear */
+            png_fixed_point gs = PNG_FP_1; /* Correction to screen */
+
+            switch (png_ptr->background_gamma_type)
+            {
+               case PNG_BACKGROUND_GAMMA_SCREEN:
+                  g = png_ptr->screen_gamma;
+                  /* gs = PNG_FP_1; */
+                  break;
+
+               case PNG_BACKGROUND_GAMMA_FILE:
+                  g = png_reciprocal(png_ptr->colorspace.gamma);
+                  gs = png_reciprocal2(png_ptr->colorspace.gamma,
+                      png_ptr->screen_gamma);
+                  break;
+
+               case PNG_BACKGROUND_GAMMA_UNIQUE:
+                  g = png_reciprocal(png_ptr->background_gamma);
+                  gs = png_reciprocal2(png_ptr->background_gamma,
+                      png_ptr->screen_gamma);
+                  break;
+
+               default:
+                  png_error(png_ptr, "invalid background gamma type");
+            }
+
+            g_sig = png_gamma_significant(g);
+            gs_sig = png_gamma_significant(gs);
+
+            if (g_sig != 0)
+               png_ptr->background_1.gray = png_gamma_correct(png_ptr,
+                   png_ptr->background.gray, g);
+
+            if (gs_sig != 0)
+               png_ptr->background.gray = png_gamma_correct(png_ptr,
+                   png_ptr->background.gray, gs);
+
+            if ((png_ptr->background.red != png_ptr->background.green) ||
+                (png_ptr->background.red != png_ptr->background.blue) ||
+                (png_ptr->background.red != png_ptr->background.gray))
+            {
+               /* RGB or RGBA with color background */
+               if (g_sig != 0)
+               {
+                  png_ptr->background_1.red = png_gamma_correct(png_ptr,
+                      png_ptr->background.red, g);
+
+                  png_ptr->background_1.green = png_gamma_correct(png_ptr,
+                      png_ptr->background.green, g);
+
+                  png_ptr->background_1.blue = png_gamma_correct(png_ptr,
+                      png_ptr->background.blue, g);
+               }
+
+               if (gs_sig != 0)
+               {
+                  png_ptr->background.red = png_gamma_correct(png_ptr,
+                      png_ptr->background.red, gs);
+
+                  png_ptr->background.green = png_gamma_correct(png_ptr,
+                      png_ptr->background.green, gs);
+
+                  png_ptr->background.blue = png_gamma_correct(png_ptr,
+                      png_ptr->background.blue, gs);
+               }
+            }
+
+            else
+            {
+               /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
+               png_ptr->background_1.red = png_ptr->background_1.green
+                   = png_ptr->background_1.blue = png_ptr->background_1.gray;
+
+               png_ptr->background.red = png_ptr->background.green
+                   = png_ptr->background.blue = png_ptr->background.gray;
+            }
+
+            /* The background is now in screen gamma: */
+            png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
+         } /* color_type != PNG_COLOR_TYPE_PALETTE */
+      }/* png_ptr->transformations & PNG_BACKGROUND */
+
+      else
+      /* Transformation does not include PNG_BACKGROUND */
+#endif /* READ_BACKGROUND */
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+         /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
+         && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
+         (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+#endif
+         )
+      {
+         png_colorp palette = png_ptr->palette;
+         int num_palette = png_ptr->num_palette;
+         int i;
+
+         /* NOTE: there are other transformations that should probably be in
+          * here too.
+          */
+         for (i = 0; i < num_palette; i++)
+         {
+            palette[i].red = png_ptr->gamma_table[palette[i].red];
+            palette[i].green = png_ptr->gamma_table[palette[i].green];
+            palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+         }
+
+         /* Done the gamma correction. */
+         png_ptr->transformations &= ~PNG_GAMMA;
+      } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
+   }
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+   else
+#endif
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+   /* No GAMMA transformation (see the hanging else 4 lines above) */
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
+   {
+      int i;
+      int istop = (int)png_ptr->num_trans;
+      png_color back;
+      png_colorp palette = png_ptr->palette;
+
+      back.red   = (png_byte)png_ptr->background.red;
+      back.green = (png_byte)png_ptr->background.green;
+      back.blue  = (png_byte)png_ptr->background.blue;
+
+      for (i = 0; i < istop; i++)
+      {
+         if (png_ptr->trans_alpha[i] == 0)
+         {
+            palette[i] = back;
+         }
+
+         else if (png_ptr->trans_alpha[i] != 0xff)
+         {
+            /* The png_composite() macro is defined in png.h */
+            png_composite(palette[i].red, palette[i].red,
+                png_ptr->trans_alpha[i], back.red);
+
+            png_composite(palette[i].green, palette[i].green,
+                png_ptr->trans_alpha[i], back.green);
+
+            png_composite(palette[i].blue, palette[i].blue,
+                png_ptr->trans_alpha[i], back.blue);
+         }
+      }
+
+      png_ptr->transformations &= ~PNG_COMPOSE;
+   }
+#endif /* READ_BACKGROUND */
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SHIFT) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) == 0 &&
+       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
+   {
+      int i;
+      int istop = png_ptr->num_palette;
+      int shift = 8 - png_ptr->sig_bit.red;
+
+      png_ptr->transformations &= ~PNG_SHIFT;
+
+      /* significant bits can be in the range 1 to 7 for a meaningful result, if
+       * the number of significant bits is 0 then no shift is done (this is an
+       * error condition which is silently ignored.)
+       */
+      if (shift > 0 && shift < 8)
+         for (i=0; i<istop; ++i)
+         {
+            int component = png_ptr->palette[i].red;
+
+            component >>= shift;
+            png_ptr->palette[i].red = (png_byte)component;
+         }
+
+      shift = 8 - png_ptr->sig_bit.green;
+      if (shift > 0 && shift < 8)
+         for (i=0; i<istop; ++i)
+         {
+            int component = png_ptr->palette[i].green;
+
+            component >>= shift;
+            png_ptr->palette[i].green = (png_byte)component;
+         }
+
+      shift = 8 - png_ptr->sig_bit.blue;
+      if (shift > 0 && shift < 8)
+         for (i=0; i<istop; ++i)
+         {
+            int component = png_ptr->palette[i].blue;
+
+            component >>= shift;
+            png_ptr->palette[i].blue = (png_byte)component;
+         }
+   }
+#endif /* READ_SHIFT */
+}
+
+/* Modify the info structure to reflect the transformations.  The
+ * info should be updated so a PNG file could be written with it,
+ * assuming the transformations result in valid PNG data.
+ */
+void /* PRIVATE */
+png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+   png_debug(1, "in png_read_transform_info");
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
+   {
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         /* This check must match what actually happens in
+          * png_do_expand_palette; if it ever checks the tRNS chunk to see if
+          * it is all opaque we must do the same (at present it does not.)
+          */
+         if (png_ptr->num_trans > 0)
+            info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+
+         else
+            info_ptr->color_type = PNG_COLOR_TYPE_RGB;
+
+         info_ptr->bit_depth = 8;
+         info_ptr->num_trans = 0;
+
+         if (png_ptr->palette == NULL)
+            png_error (png_ptr, "Palette is NULL in indexed image");
+      }
+      else
+      {
+         if (png_ptr->num_trans != 0)
+         {
+            if ((png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
+               info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+         }
+         if (info_ptr->bit_depth < 8)
+            info_ptr->bit_depth = 8;
+
+         info_ptr->num_trans = 0;
+      }
+   }
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+   /* The following is almost certainly wrong unless the background value is in
+    * the screen space!
+    */
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+      info_ptr->background = png_ptr->background;
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
+    * however it seems that the code in png_init_read_transformations, which has
+    * been called before this from png_read_update_info->png_read_start_row
+    * sometimes does the gamma transform and cancels the flag.
+    *
+    * TODO: this looks wrong; the info_ptr should end up with a gamma equal to
+    * the screen_gamma value.  The following probably results in weirdness if
+    * the info_ptr is used by the app after the rows have been read.
+    */
+   info_ptr->colorspace.gamma = png_ptr->colorspace.gamma;
+#endif
+
+   if (info_ptr->bit_depth == 16)
+   {
+#  ifdef PNG_READ_16BIT_SUPPORTED
+#     ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+         if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
+            info_ptr->bit_depth = 8;
+#     endif
+
+#     ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+         if ((png_ptr->transformations & PNG_16_TO_8) != 0)
+            info_ptr->bit_depth = 8;
+#     endif
+
+#  else
+      /* No 16-bit support: force chopping 16-bit input down to 8, in this case
+       * the app program can chose if both APIs are available by setting the
+       * correct scaling to use.
+       */
+#     ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+         /* For compatibility with previous versions use the strip method by
+          * default.  This code works because if PNG_SCALE_16_TO_8 is already
+          * set the code below will do that in preference to the chop.
+          */
+         png_ptr->transformations |= PNG_16_TO_8;
+         info_ptr->bit_depth = 8;
+#     else
+
+#        ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+            png_ptr->transformations |= PNG_SCALE_16_TO_8;
+            info_ptr->bit_depth = 8;
+#        else
+
+            CONFIGURATION ERROR: you must enable at least one 16 to 8 method
+#        endif
+#    endif
+#endif /* !READ_16BIT */
+   }
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
+      info_ptr->color_type = (png_byte)(info_ptr->color_type |
+         PNG_COLOR_MASK_COLOR);
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+      info_ptr->color_type = (png_byte)(info_ptr->color_type &
+         ~PNG_COLOR_MASK_COLOR);
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
+   {
+      if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
+          (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
+          png_ptr->palette_lookup != 0 && info_ptr->bit_depth == 8)
+      {
+         info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
+      }
+   }
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+       info_ptr->bit_depth == 8 &&
+       info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      info_ptr->bit_depth = 16;
+   }
+#endif
+
+#ifdef PNG_READ_PACK_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACK) != 0 &&
+       (info_ptr->bit_depth < 8))
+      info_ptr->bit_depth = 8;
+#endif
+
+   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      info_ptr->channels = 1;
+
+   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      info_ptr->channels = 3;
+
+   else
+      info_ptr->channels = 1;
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0)
+   {
+      info_ptr->color_type = (png_byte)(info_ptr->color_type &
+         ~PNG_COLOR_MASK_ALPHA);
+      info_ptr->num_trans = 0;
+   }
+#endif
+
+   if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      info_ptr->channels++;
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+   /* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */
+   if ((png_ptr->transformations & PNG_FILLER) != 0 &&
+       (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+       info_ptr->color_type == PNG_COLOR_TYPE_GRAY))
+   {
+      info_ptr->channels++;
+      /* If adding a true alpha channel not just filler */
+      if ((png_ptr->transformations & PNG_ADD_ALPHA) != 0)
+         info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+   }
+#endif
+
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
+defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+   {
+      if (png_ptr->user_transform_depth != 0)
+         info_ptr->bit_depth = png_ptr->user_transform_depth;
+
+      if (png_ptr->user_transform_channels != 0)
+         info_ptr->channels = png_ptr->user_transform_channels;
+   }
+#endif
+
+   info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
+       info_ptr->bit_depth);
+
+   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
+
+   /* Adding in 1.5.4: cache the above value in png_struct so that we can later
+    * check in png_rowbytes that the user buffer won't get overwritten.  Note
+    * that the field is not always set - if png_read_update_info isn't called
+    * the application has to either not do any transforms or get the calculation
+    * right itself.
+    */
+   png_ptr->info_rowbytes = info_ptr->rowbytes;
+
+#ifndef PNG_READ_EXPAND_SUPPORTED
+   if (png_ptr != NULL)
+      return;
+#endif
+}
+
+#ifdef PNG_READ_PACK_SUPPORTED
+/* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
+ * without changing the actual values.  Thus, if you had a row with
+ * a bit depth of 1, you would end up with bytes that only contained
+ * the numbers 0 or 1.  If you would rather they contain 0 and 255, use
+ * png_do_shift() after this.
+ */
+static void
+png_do_unpack(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_unpack");
+
+   if (row_info->bit_depth < 8)
+   {
+      png_uint_32 i;
+      png_uint_32 row_width=row_info->width;
+
+      switch (row_info->bit_depth)
+      {
+         case 1:
+         {
+            png_bytep sp = row + (size_t)((row_width - 1) >> 3);
+            png_bytep dp = row + (size_t)row_width - 1;
+            png_uint_32 shift = 7U - ((row_width + 7U) & 0x07);
+            for (i = 0; i < row_width; i++)
+            {
+               *dp = (png_byte)((*sp >> shift) & 0x01);
+
+               if (shift == 7)
+               {
+                  shift = 0;
+                  sp--;
+               }
+
+               else
+                  shift++;
+
+               dp--;
+            }
+            break;
+         }
+
+         case 2:
+         {
+
+            png_bytep sp = row + (size_t)((row_width - 1) >> 2);
+            png_bytep dp = row + (size_t)row_width - 1;
+            png_uint_32 shift = ((3U - ((row_width + 3U) & 0x03)) << 1);
+            for (i = 0; i < row_width; i++)
+            {
+               *dp = (png_byte)((*sp >> shift) & 0x03);
+
+               if (shift == 6)
+               {
+                  shift = 0;
+                  sp--;
+               }
+
+               else
+                  shift += 2;
+
+               dp--;
+            }
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp = row + (size_t)((row_width - 1) >> 1);
+            png_bytep dp = row + (size_t)row_width - 1;
+            png_uint_32 shift = ((1U - ((row_width + 1U) & 0x01)) << 2);
+            for (i = 0; i < row_width; i++)
+            {
+               *dp = (png_byte)((*sp >> shift) & 0x0f);
+
+               if (shift == 4)
+               {
+                  shift = 0;
+                  sp--;
+               }
+
+               else
+                  shift = 4;
+
+               dp--;
+            }
+            break;
+         }
+
+         default:
+            break;
+      }
+      row_info->bit_depth = 8;
+      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->rowbytes = row_width * row_info->channels;
+   }
+}
+#endif
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+/* Reverse the effects of png_do_shift.  This routine merely shifts the
+ * pixels back to their significant bits values.  Thus, if you have
+ * a row of bit depth 8, but only 5 are significant, this will shift
+ * the values back to 0 through 31.
+ */
+static void
+png_do_unshift(png_row_infop row_info, png_bytep row,
+    png_const_color_8p sig_bits)
+{
+   int color_type;
+
+   png_debug(1, "in png_do_unshift");
+
+   /* The palette case has already been handled in the _init routine. */
+   color_type = row_info->color_type;
+
+   if (color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      int shift[4];
+      int channels = 0;
+      int bit_depth = row_info->bit_depth;
+
+      if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+      {
+         shift[channels++] = bit_depth - sig_bits->red;
+         shift[channels++] = bit_depth - sig_bits->green;
+         shift[channels++] = bit_depth - sig_bits->blue;
+      }
+
+      else
+      {
+         shift[channels++] = bit_depth - sig_bits->gray;
+      }
+
+      if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      {
+         shift[channels++] = bit_depth - sig_bits->alpha;
+      }
+
+      {
+         int c, have_shift;
+
+         for (c = have_shift = 0; c < channels; ++c)
+         {
+            /* A shift of more than the bit depth is an error condition but it
+             * gets ignored here.
+             */
+            if (shift[c] <= 0 || shift[c] >= bit_depth)
+               shift[c] = 0;
+
+            else
+               have_shift = 1;
+         }
+
+         if (have_shift == 0)
+            return;
+      }
+
+      switch (bit_depth)
+      {
+         default:
+         /* Must be 1bpp gray: should not be here! */
+            /* NOTREACHED */
+            break;
+
+         case 2:
+         /* Must be 2bpp gray */
+         /* assert(channels == 1 && shift[0] == 1) */
+         {
+            png_bytep bp = row;
+            png_bytep bp_end = bp + row_info->rowbytes;
+
+            while (bp < bp_end)
+            {
+               int b = (*bp >> 1) & 0x55;
+               *bp++ = (png_byte)b;
+            }
+            break;
+         }
+
+         case 4:
+         /* Must be 4bpp gray */
+         /* assert(channels == 1) */
+         {
+            png_bytep bp = row;
+            png_bytep bp_end = bp + row_info->rowbytes;
+            int gray_shift = shift[0];
+            int mask =  0xf >> gray_shift;
+
+            mask |= mask << 4;
+
+            while (bp < bp_end)
+            {
+               int b = (*bp >> gray_shift) & mask;
+               *bp++ = (png_byte)b;
+            }
+            break;
+         }
+
+         case 8:
+         /* Single byte components, G, GA, RGB, RGBA */
+         {
+            png_bytep bp = row;
+            png_bytep bp_end = bp + row_info->rowbytes;
+            int channel = 0;
+
+            while (bp < bp_end)
+            {
+               int b = *bp >> shift[channel];
+               if (++channel >= channels)
+                  channel = 0;
+               *bp++ = (png_byte)b;
+            }
+            break;
+         }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+         case 16:
+         /* Double byte components, G, GA, RGB, RGBA */
+         {
+            png_bytep bp = row;
+            png_bytep bp_end = bp + row_info->rowbytes;
+            int channel = 0;
+
+            while (bp < bp_end)
+            {
+               int value = (bp[0] << 8) + bp[1];
+
+               value >>= shift[channel];
+               if (++channel >= channels)
+                  channel = 0;
+               *bp++ = (png_byte)(value >> 8);
+               *bp++ = (png_byte)value;
+            }
+            break;
+         }
+#endif
+      }
+   }
+}
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+/* Scale rows of bit depth 16 down to 8 accurately */
+static void
+png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_scale_16_to_8");
+
+   if (row_info->bit_depth == 16)
+   {
+      png_bytep sp = row; /* source */
+      png_bytep dp = row; /* destination */
+      png_bytep ep = sp + row_info->rowbytes; /* end+1 */
+
+      while (sp < ep)
+      {
+         /* The input is an array of 16-bit components, these must be scaled to
+          * 8 bits each.  For a 16-bit value V the required value (from the PNG
+          * specification) is:
+          *
+          *    (V * 255) / 65535
+          *
+          * This reduces to round(V / 257), or floor((V + 128.5)/257)
+          *
+          * Represent V as the two byte value vhi.vlo.  Make a guess that the
+          * result is the top byte of V, vhi, then the correction to this value
+          * is:
+          *
+          *    error = floor(((V-vhi.vhi) + 128.5) / 257)
+          *          = floor(((vlo-vhi) + 128.5) / 257)
+          *
+          * This can be approximated using integer arithmetic (and a signed
+          * shift):
+          *
+          *    error = (vlo-vhi+128) >> 8;
+          *
+          * The approximate differs from the exact answer only when (vlo-vhi) is
+          * 128; it then gives a correction of +1 when the exact correction is
+          * 0.  This gives 128 errors.  The exact answer (correct for all 16-bit
+          * input values) is:
+          *
+          *    error = (vlo-vhi+128)*65535 >> 24;
+          *
+          * An alternative arithmetic calculation which also gives no errors is:
+          *
+          *    (V * 255 + 32895) >> 16
+          */
+
+         png_int_32 tmp = *sp++; /* must be signed! */
+         tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
+         *dp++ = (png_byte)tmp;
+      }
+
+      row_info->bit_depth = 8;
+      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->rowbytes = row_info->width * row_info->channels;
+   }
+}
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+static void
+/* Simply discard the low byte.  This was the default behavior prior
+ * to libpng-1.5.4.
+ */
+png_do_chop(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_chop");
+
+   if (row_info->bit_depth == 16)
+   {
+      png_bytep sp = row; /* source */
+      png_bytep dp = row; /* destination */
+      png_bytep ep = sp + row_info->rowbytes; /* end+1 */
+
+      while (sp < ep)
+      {
+         *dp++ = *sp;
+         sp += 2; /* skip low byte */
+      }
+
+      row_info->bit_depth = 8;
+      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->rowbytes = row_info->width * row_info->channels;
+   }
+}
+#endif
+
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+static void
+png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_uint_32 row_width = row_info->width;
+
+   png_debug(1, "in png_do_read_swap_alpha");
+
+   if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+   {
+      /* This converts from RGBA to ARGB */
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            save = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      /* This converts from RRGGBBAA to AARRGGBB */
+      else
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save[2];
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            save[0] = *(--sp);
+            save[1] = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save[0];
+            *(--dp) = save[1];
+         }
+      }
+#endif
+   }
+
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+   {
+      /* This converts from GA to AG */
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            save = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      /* This converts from GGAA to AAGG */
+      else
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save[2];
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            save[0] = *(--sp);
+            save[1] = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save[0];
+            *(--dp) = save[1];
+         }
+      }
+#endif
+   }
+}
+#endif
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+static void
+png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_uint_32 row_width;
+   png_debug(1, "in png_do_read_invert_alpha");
+
+   row_width = row_info->width;
+   if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         /* This inverts the alpha channel in RGBA */
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            *(--dp) = (png_byte)(255 - *(--sp));
+
+/*          This does nothing:
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            We can replace it with:
+*/
+            sp-=3;
+            dp=sp;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      /* This inverts the alpha channel in RRGGBBAA */
+      else
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = (png_byte)(255 - *(--sp));
+
+/*          This does nothing:
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            We can replace it with:
+*/
+            sp-=6;
+            dp=sp;
+         }
+      }
+#endif
+   }
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         /* This inverts the alpha channel in GA */
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = *(--sp);
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      else
+      {
+         /* This inverts the alpha channel in GGAA */
+         png_bytep sp  = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = (png_byte)(255 - *(--sp));
+/*
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+*/
+            sp-=2;
+            dp=sp;
+         }
+      }
+#endif
+   }
+}
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+/* Add filler channel if we have RGB color */
+static void
+png_do_read_filler(png_row_infop row_info, png_bytep row,
+    png_uint_32 filler, png_uint_32 flags)
+{
+   png_uint_32 i;
+   png_uint_32 row_width = row_info->width;
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+   png_byte hi_filler = (png_byte)(filler>>8);
+#endif
+   png_byte lo_filler = (png_byte)filler;
+
+   png_debug(1, "in png_do_read_filler");
+
+   if (
+       row_info->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+         {
+            /* This changes the data from G to GX */
+            png_bytep sp = row + (size_t)row_width;
+            png_bytep dp =  sp + (size_t)row_width;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            row_info->channels = 2;
+            row_info->pixel_depth = 16;
+            row_info->rowbytes = row_width * 2;
+         }
+
+         else
+         {
+            /* This changes the data from G to XG */
+            png_bytep sp = row + (size_t)row_width;
+            png_bytep dp = sp  + (size_t)row_width;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+            }
+            row_info->channels = 2;
+            row_info->pixel_depth = 16;
+            row_info->rowbytes = row_width * 2;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      else if (row_info->bit_depth == 16)
+      {
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+         {
+            /* This changes the data from GG to GGXX */
+            png_bytep sp = row + (size_t)row_width * 2;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            *(--dp) = hi_filler;
+            row_info->channels = 2;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+
+         else
+         {
+            /* This changes the data from GG to XXGG */
+            png_bytep sp = row + (size_t)row_width * 2;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
+            }
+            row_info->channels = 2;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+      }
+#endif
+   } /* COLOR_TYPE == GRAY */
+   else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+         {
+            /* This changes the data from RGB to RGBX */
+            png_bytep sp = row + (size_t)row_width * 3;
+            png_bytep dp = sp  + (size_t)row_width;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            row_info->channels = 4;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+
+         else
+         {
+            /* This changes the data from RGB to XRGB */
+            png_bytep sp = row + (size_t)row_width * 3;
+            png_bytep dp = sp + (size_t)row_width;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+            }
+            row_info->channels = 4;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      else if (row_info->bit_depth == 16)
+      {
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+         {
+            /* This changes the data from RRGGBB to RRGGBBXX */
+            png_bytep sp = row + (size_t)row_width * 6;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            *(--dp) = hi_filler;
+            row_info->channels = 4;
+            row_info->pixel_depth = 64;
+            row_info->rowbytes = row_width * 8;
+         }
+
+         else
+         {
+            /* This changes the data from RRGGBB to XXRRGGBB */
+            png_bytep sp = row + (size_t)row_width * 6;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
+            }
+
+            row_info->channels = 4;
+            row_info->pixel_depth = 64;
+            row_info->rowbytes = row_width * 8;
+         }
+      }
+#endif
+   } /* COLOR_TYPE == RGB */
+}
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* Expand grayscale files to RGB, with or without alpha */
+static void
+png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
+{
+   png_uint_32 i;
+   png_uint_32 row_width = row_info->width;
+
+   png_debug(1, "in png_do_gray_to_rgb");
+
+   if (row_info->bit_depth >= 8 &&
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) == 0)
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This changes G to RGB */
+            png_bytep sp = row + (size_t)row_width - 1;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *sp;
+               *(dp--) = *sp;
+               *(dp--) = *(sp--);
+            }
+         }
+
+         else
+         {
+            /* This changes GG to RRGGBB */
+            png_bytep sp = row + (size_t)row_width * 2 - 1;
+            png_bytep dp = sp  + (size_t)row_width * 4;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);
+            }
+         }
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This changes GA to RGBA */
+            png_bytep sp = row + (size_t)row_width * 2 - 1;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *(sp--);
+               *(dp--) = *sp;
+               *(dp--) = *sp;
+               *(dp--) = *(sp--);
+            }
+         }
+
+         else
+         {
+            /* This changes GGAA to RRGGBBAA */
+            png_bytep sp = row + (size_t)row_width * 4 - 1;
+            png_bytep dp = sp  + (size_t)row_width * 4;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);
+            }
+         }
+      }
+      row_info->channels = (png_byte)(row_info->channels + 2);
+      row_info->color_type |= PNG_COLOR_MASK_COLOR;
+      row_info->pixel_depth = (png_byte)(row_info->channels *
+          row_info->bit_depth);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+   }
+}
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* Reduce RGB files to grayscale, with or without alpha
+ * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
+ * <http://www.inforamp.net/~poynton/>  (THIS LINK IS DEAD June 2008 but
+ * versions dated 1998 through November 2002 have been archived at
+ * https://web.archive.org/web/20000816232553/www.inforamp.net/
+ * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
+ * Charles Poynton poynton at poynton.com
+ *
+ *     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+ *
+ *  which can be expressed with integers as
+ *
+ *     Y = (6969 * R + 23434 * G + 2365 * B)/32768
+ *
+ * Poynton's current link (as of January 2003 through July 2011):
+ * <http://www.poynton.com/notes/colour_and_gamma/>
+ * has changed the numbers slightly:
+ *
+ *     Y = 0.2126*R + 0.7152*G + 0.0722*B
+ *
+ *  which can be expressed with integers as
+ *
+ *     Y = (6966 * R + 23436 * G + 2366 * B)/32768
+ *
+ *  Historically, however, libpng uses numbers derived from the ITU-R Rec 709
+ *  end point chromaticities and the D65 white point.  Depending on the
+ *  precision used for the D65 white point this produces a variety of different
+ *  numbers, however if the four decimal place value used in ITU-R Rec 709 is
+ *  used (0.3127,0.3290) the Y calculation would be:
+ *
+ *     Y = (6968 * R + 23435 * G + 2366 * B)/32768
+ *
+ *  While this is correct the rounding results in an overflow for white, because
+ *  the sum of the rounded coefficients is 32769, not 32768.  Consequently
+ *  libpng uses, instead, the closest non-overflowing approximation:
+ *
+ *     Y = (6968 * R + 23434 * G + 2366 * B)/32768
+ *
+ *  Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
+ *  (including an sRGB chunk) then the chromaticities are used to calculate the
+ *  coefficients.  See the chunk handling in pngrutil.c for more information.
+ *
+ *  In all cases the calculation is to be done in a linear colorspace.  If no
+ *  gamma information is available to correct the encoding of the original RGB
+ *  values this results in an implicit assumption that the original PNG RGB
+ *  values were linear.
+ *
+ *  Other integer coefficients can be used via png_set_rgb_to_gray().  Because
+ *  the API takes just red and green coefficients the blue coefficient is
+ *  calculated to make the sum 32768.  This will result in different rounding
+ *  to that used above.
+ */
+static int
+png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
+{
+   int rgb_error = 0;
+
+   png_debug(1, "in png_do_rgb_to_gray");
+
+   if ((row_info->color_type & PNG_COLOR_MASK_PALETTE) == 0 &&
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
+      png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
+      png_uint_32 bc = 32768 - rc - gc;
+      png_uint_32 row_width = row_info->width;
+      int have_alpha = (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
+
+      if (row_info->bit_depth == 8)
+      {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+         /* Notice that gamma to/from 1 are not necessarily inverses (if
+          * there is an overall gamma correction).  Prior to 1.5.5 this code
+          * checked the linearized values for equality; this doesn't match
+          * the documentation, the original values must be checked.
+          */
+         if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+         {
+            png_bytep sp = row;
+            png_bytep dp = row;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte red   = *(sp++);
+               png_byte green = *(sp++);
+               png_byte blue  = *(sp++);
+
+               if (red != green || red != blue)
+               {
+                  red = png_ptr->gamma_to_1[red];
+                  green = png_ptr->gamma_to_1[green];
+                  blue = png_ptr->gamma_to_1[blue];
+
+                  rgb_error |= 1;
+                  *(dp++) = png_ptr->gamma_from_1[
+                      (rc*red + gc*green + bc*blue + 16384)>>15];
+               }
+
+               else
+               {
+                  /* If there is no overall correction the table will not be
+                   * set.
+                   */
+                  if (png_ptr->gamma_table != NULL)
+                     red = png_ptr->gamma_table[red];
+
+                  *(dp++) = red;
+               }
+
+               if (have_alpha != 0)
+                  *(dp++) = *(sp++);
+            }
+         }
+         else
+#endif
+         {
+            png_bytep sp = row;
+            png_bytep dp = row;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte red   = *(sp++);
+               png_byte green = *(sp++);
+               png_byte blue  = *(sp++);
+
+               if (red != green || red != blue)
+               {
+                  rgb_error |= 1;
+                  /* NOTE: this is the historical approach which simply
+                   * truncates the results.
+                   */
+                  *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
+               }
+
+               else
+                  *(dp++) = red;
+
+               if (have_alpha != 0)
+                  *(dp++) = *(sp++);
+            }
+         }
+      }
+
+      else /* RGB bit_depth == 16 */
+      {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+         if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
+         {
+            png_bytep sp = row;
+            png_bytep dp = row;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_uint_16 red, green, blue, w;
+               png_byte hi,lo;
+
+               hi=*(sp)++; lo=*(sp)++; red   = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; blue  = (png_uint_16)((hi << 8) | (lo));
+
+               if (red == green && red == blue)
+               {
+                  if (png_ptr->gamma_16_table != NULL)
+                     w = png_ptr->gamma_16_table[(red & 0xff)
+                         >> png_ptr->gamma_shift][red >> 8];
+
+                  else
+                     w = red;
+               }
+
+               else
+               {
+                  png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red & 0xff)
+                      >> png_ptr->gamma_shift][red>>8];
+                  png_uint_16 green_1 =
+                      png_ptr->gamma_16_to_1[(green & 0xff) >>
+                      png_ptr->gamma_shift][green>>8];
+                  png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue & 0xff)
+                      >> png_ptr->gamma_shift][blue>>8];
+                  png_uint_16 gray16  = (png_uint_16)((rc*red_1 + gc*green_1
+                      + bc*blue_1 + 16384)>>15);
+                  w = png_ptr->gamma_16_from_1[(gray16 & 0xff) >>
+                      png_ptr->gamma_shift][gray16 >> 8];
+                  rgb_error |= 1;
+               }
+
+               *(dp++) = (png_byte)((w>>8) & 0xff);
+               *(dp++) = (png_byte)(w & 0xff);
+
+               if (have_alpha != 0)
+               {
+                  *(dp++) = *(sp++);
+                  *(dp++) = *(sp++);
+               }
+            }
+         }
+         else
+#endif
+         {
+            png_bytep sp = row;
+            png_bytep dp = row;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_uint_16 red, green, blue, gray16;
+               png_byte hi,lo;
+
+               hi=*(sp)++; lo=*(sp)++; red   = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; blue  = (png_uint_16)((hi << 8) | (lo));
+
+               if (red != green || red != blue)
+                  rgb_error |= 1;
+
+               /* From 1.5.5 in the 16-bit case do the accurate conversion even
+                * in the 'fast' case - this is because this is where the code
+                * ends up when handling linear 16-bit data.
+                */
+               gray16  = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
+                  15);
+               *(dp++) = (png_byte)((gray16 >> 8) & 0xff);
+               *(dp++) = (png_byte)(gray16 & 0xff);
+
+               if (have_alpha != 0)
+               {
+                  *(dp++) = *(sp++);
+                  *(dp++) = *(sp++);
+               }
+            }
+         }
+      }
+
+      row_info->channels = (png_byte)(row_info->channels - 2);
+      row_info->color_type = (png_byte)(row_info->color_type &
+          ~PNG_COLOR_MASK_COLOR);
+      row_info->pixel_depth = (png_byte)(row_info->channels *
+          row_info->bit_depth);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+   }
+   return rgb_error;
+}
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+/* Replace any alpha or transparency with the supplied background color.
+ * "background" is already in the screen gamma, while "background_1" is
+ * at a gamma of 1.0.  Paletted files have already been taken care of.
+ */
+static void
+png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
+{
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   png_const_bytep gamma_table = png_ptr->gamma_table;
+   png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
+   png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
+   png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
+   png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
+   png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
+   int gamma_shift = png_ptr->gamma_shift;
+   int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
+#endif
+
+   png_bytep sp;
+   png_uint_32 i;
+   png_uint_32 row_width = row_info->width;
+   int shift;
+
+   png_debug(1, "in png_do_compose");
+
+   switch (row_info->color_type)
+   {
+      case PNG_COLOR_TYPE_GRAY:
+      {
+         switch (row_info->bit_depth)
+         {
+            case 1:
+            {
+               sp = row;
+               shift = 7;
+               for (i = 0; i < row_width; i++)
+               {
+                  if ((png_uint_16)((*sp >> shift) & 0x01)
+                     == png_ptr->trans_color.gray)
+                  {
+                     unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
+                     tmp |=
+                         (unsigned int)(png_ptr->background.gray << shift);
+                     *sp = (png_byte)(tmp & 0xff);
+                  }
+
+                  if (shift == 0)
+                  {
+                     shift = 7;
+                     sp++;
+                  }
+
+                  else
+                     shift--;
+               }
+               break;
+            }
+
+            case 2:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_table != NULL)
+               {
+                  sp = row;
+                  shift = 6;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x03)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+                        tmp |=
+                           (unsigned int)png_ptr->background.gray << shift;
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     else
+                     {
+                        unsigned int p = (*sp >> shift) & 0x03;
+                        unsigned int g = (gamma_table [p | (p << 2) |
+                            (p << 4) | (p << 6)] >> 6) & 0x03;
+                        unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+                        tmp |= (unsigned int)(g << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 6;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 2;
+                  }
+               }
+
+               else
+#endif
+               {
+                  sp = row;
+                  shift = 6;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x03)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+                        tmp |=
+                            (unsigned int)png_ptr->background.gray << shift;
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 6;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 2;
+                  }
+               }
+               break;
+            }
+
+            case 4:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_table != NULL)
+               {
+                  sp = row;
+                  shift = 4;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x0f)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
+                        tmp |=
+                           (unsigned int)(png_ptr->background.gray << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     else
+                     {
+                        unsigned int p = (*sp >> shift) & 0x0f;
+                        unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
+                           0x0f;
+                        unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
+                        tmp |= (unsigned int)(g << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 4;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 4;
+                  }
+               }
+
+               else
+#endif
+               {
+                  sp = row;
+                  shift = 4;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x0f)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
+                        tmp |=
+                           (unsigned int)(png_ptr->background.gray << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 4;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 4;
+                  }
+               }
+               break;
+            }
+
+            case 8:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_table != NULL)
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp++)
+                  {
+                     if (*sp == png_ptr->trans_color.gray)
+                        *sp = (png_byte)png_ptr->background.gray;
+
+                     else
+                        *sp = gamma_table[*sp];
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp++)
+                  {
+                     if (*sp == png_ptr->trans_color.gray)
+                        *sp = (png_byte)png_ptr->background.gray;
+                  }
+               }
+               break;
+            }
+
+            case 16:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_16 != NULL)
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp += 2)
+                  {
+                     png_uint_16 v;
+
+                     v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                     if (v == png_ptr->trans_color.gray)
+                     {
+                        /* Background is already in screen gamma */
+                        *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                        *(sp + 1) = (png_byte)(png_ptr->background.gray
+                             & 0xff);
+                     }
+
+                     else
+                     {
+                        v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                        *sp = (png_byte)((v >> 8) & 0xff);
+                        *(sp + 1) = (png_byte)(v & 0xff);
+                     }
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp += 2)
+                  {
+                     png_uint_16 v;
+
+                     v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                     if (v == png_ptr->trans_color.gray)
+                     {
+                        *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                        *(sp + 1) = (png_byte)(png_ptr->background.gray
+                             & 0xff);
+                     }
+                  }
+               }
+               break;
+            }
+
+            default:
+               break;
+         }
+         break;
+      }
+
+      case PNG_COLOR_TYPE_RGB:
+      {
+         if (row_info->bit_depth == 8)
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_table != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 3)
+               {
+                  if (*sp == png_ptr->trans_color.red &&
+                      *(sp + 1) == png_ptr->trans_color.green &&
+                      *(sp + 2) == png_ptr->trans_color.blue)
+                  {
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+
+                  else
+                  {
+                     *sp = gamma_table[*sp];
+                     *(sp + 1) = gamma_table[*(sp + 1)];
+                     *(sp + 2) = gamma_table[*(sp + 2)];
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 3)
+               {
+                  if (*sp == png_ptr->trans_color.red &&
+                      *(sp + 1) == png_ptr->trans_color.green &&
+                      *(sp + 2) == png_ptr->trans_color.blue)
+                  {
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+               }
+            }
+         }
+         else /* if (row_info->bit_depth == 16) */
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_16 != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 6)
+               {
+                  png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                  png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                      + *(sp + 5));
+
+                  if (r == png_ptr->trans_color.red &&
+                      g == png_ptr->trans_color.green &&
+                      b == png_ptr->trans_color.blue)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+
+                  else
+                  {
+                     png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                     *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                     *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(v & 0xff);
+                  }
+               }
+            }
+
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 6)
+               {
+                  png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                  png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                      + *(sp + 5));
+
+                  if (r == png_ptr->trans_color.red &&
+                      g == png_ptr->trans_color.green &&
+                      b == png_ptr->trans_color.blue)
+                  {
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+               }
+            }
+         }
+         break;
+      }
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+      {
+         if (row_info->bit_depth == 8)
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+                gamma_table != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 2)
+               {
+                  png_uint_16 a = *(sp + 1);
+
+                  if (a == 0xff)
+                     *sp = gamma_table[*sp];
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)png_ptr->background.gray;
+                  }
+
+                  else
+                  {
+                     png_byte v, w;
+
+                     v = gamma_to_1[*sp];
+                     png_composite(w, v, a, png_ptr->background_1.gray);
+                     if (optimize == 0)
+                        w = gamma_from_1[w];
+                     *sp = w;
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 2)
+               {
+                  png_byte a = *(sp + 1);
+
+                  if (a == 0)
+                     *sp = (png_byte)png_ptr->background.gray;
+
+                  else if (a < 0xff)
+                     png_composite(*sp, *sp, a, png_ptr->background.gray);
+               }
+            }
+         }
+         else /* if (png_ptr->bit_depth == 16) */
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+                gamma_16_to_1 != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  if (a == (png_uint_16)0xffff)
+                  {
+                     png_uint_16 v;
+
+                     v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+                  }
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+                  }
+
+                  else
+                  {
+                     png_uint_16 g, v, w;
+
+                     g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+                     png_composite_16(v, g, a, png_ptr->background_1.gray);
+                     if (optimize != 0)
+                        w = v;
+                     else
+                        w = gamma_16_from_1[(v & 0xff) >>
+                            gamma_shift][v >> 8];
+                     *sp = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(w & 0xff);
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  if (a == 0)
+                  {
+                     *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+                  }
+
+                  else if (a < 0xffff)
+                  {
+                     png_uint_16 g, v;
+
+                     g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                     png_composite_16(v, g, a, png_ptr->background.gray);
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+                  }
+               }
+            }
+         }
+         break;
+      }
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+      {
+         if (row_info->bit_depth == 8)
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+                gamma_table != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_byte a = *(sp + 3);
+
+                  if (a == 0xff)
+                  {
+                     *sp = gamma_table[*sp];
+                     *(sp + 1) = gamma_table[*(sp + 1)];
+                     *(sp + 2) = gamma_table[*(sp + 2)];
+                  }
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+
+                  else
+                  {
+                     png_byte v, w;
+
+                     v = gamma_to_1[*sp];
+                     png_composite(w, v, a, png_ptr->background_1.red);
+                     if (optimize == 0) w = gamma_from_1[w];
+                     *sp = w;
+
+                     v = gamma_to_1[*(sp + 1)];
+                     png_composite(w, v, a, png_ptr->background_1.green);
+                     if (optimize == 0) w = gamma_from_1[w];
+                     *(sp + 1) = w;
+
+                     v = gamma_to_1[*(sp + 2)];
+                     png_composite(w, v, a, png_ptr->background_1.blue);
+                     if (optimize == 0) w = gamma_from_1[w];
+                     *(sp + 2) = w;
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_byte a = *(sp + 3);
+
+                  if (a == 0)
+                  {
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+
+                  else if (a < 0xff)
+                  {
+                     png_composite(*sp, *sp, a, png_ptr->background.red);
+
+                     png_composite(*(sp + 1), *(sp + 1), a,
+                         png_ptr->background.green);
+
+                     png_composite(*(sp + 2), *(sp + 2), a,
+                         png_ptr->background.blue);
+                  }
+               }
+            }
+         }
+         else /* if (row_info->bit_depth == 16) */
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+                gamma_16_to_1 != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 8)
+               {
+                  png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+                      << 8) + (png_uint_16)(*(sp + 7)));
+
+                  if (a == (png_uint_16)0xffff)
+                  {
+                     png_uint_16 v;
+
+                     v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                     *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                     *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(v & 0xff);
+                  }
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+
+                  else
+                  {
+                     png_uint_16 v, w;
+
+                     v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+                     png_composite_16(w, v, a, png_ptr->background_1.red);
+                     if (optimize == 0)
+                        w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                             8];
+                     *sp = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(w & 0xff);
+
+                     v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                     png_composite_16(w, v, a, png_ptr->background_1.green);
+                     if (optimize == 0)
+                        w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                             8];
+
+                     *(sp + 2) = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(w & 0xff);
+
+                     v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                     png_composite_16(w, v, a, png_ptr->background_1.blue);
+                     if (optimize == 0)
+                        w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                             8];
+
+                     *(sp + 4) = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(w & 0xff);
+                  }
+               }
+            }
+
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 8)
+               {
+                  png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+                      << 8) + (png_uint_16)(*(sp + 7)));
+
+                  if (a == 0)
+                  {
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+
+                  else if (a < 0xffff)
+                  {
+                     png_uint_16 v;
+
+                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                     png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                         + *(sp + 3));
+                     png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                         + *(sp + 5));
+
+                     png_composite_16(v, r, a, png_ptr->background.red);
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+
+                     png_composite_16(v, g, a, png_ptr->background.green);
+                     *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(v & 0xff);
+
+                     png_composite_16(v, b, a, png_ptr->background.blue);
+                     *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(v & 0xff);
+                  }
+               }
+            }
+         }
+         break;
+      }
+
+      default:
+         break;
+   }
+}
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Gamma correct the image, avoiding the alpha channel.  Make sure
+ * you do this after you deal with the transparency issue on grayscale
+ * or RGB images. If your bit depth is 8, use gamma_table, if it
+ * is 16, use gamma_16_table and gamma_shift.  Build these with
+ * build_gamma_table().
+ */
+static void
+png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
+{
+   png_const_bytep gamma_table = png_ptr->gamma_table;
+   png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
+   int gamma_shift = png_ptr->gamma_shift;
+
+   png_bytep sp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_gamma");
+
+   if (((row_info->bit_depth <= 8 && gamma_table != NULL) ||
+       (row_info->bit_depth == 16 && gamma_16_table != NULL)))
+   {
+      switch (row_info->color_type)
+      {
+         case PNG_COLOR_TYPE_RGB:
+         {
+            if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp++;
+                  *sp = gamma_table[*sp];
+                  sp++;
+                  *sp = gamma_table[*sp];
+                  sp++;
+               }
+            }
+
+            else /* if (row_info->bit_depth == 16) */
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+               }
+            }
+            break;
+         }
+
+         case PNG_COLOR_TYPE_RGB_ALPHA:
+         {
+            if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp++;
+
+                  *sp = gamma_table[*sp];
+                  sp++;
+
+                  *sp = gamma_table[*sp];
+                  sp++;
+
+                  sp++;
+               }
+            }
+
+            else /* if (row_info->bit_depth == 16) */
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 4;
+               }
+            }
+            break;
+         }
+
+         case PNG_COLOR_TYPE_GRAY_ALPHA:
+         {
+            if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp += 2;
+               }
+            }
+
+            else /* if (row_info->bit_depth == 16) */
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 4;
+               }
+            }
+            break;
+         }
+
+         case PNG_COLOR_TYPE_GRAY:
+         {
+            if (row_info->bit_depth == 2)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i += 4)
+               {
+                  int a = *sp & 0xc0;
+                  int b = *sp & 0x30;
+                  int c = *sp & 0x0c;
+                  int d = *sp & 0x03;
+
+                  *sp = (png_byte)(
+                      ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])   ) & 0xc0)|
+                      ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
+                      ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
+                      ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
+                  sp++;
+               }
+            }
+
+            if (row_info->bit_depth == 4)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i += 2)
+               {
+                  int msb = *sp & 0xf0;
+                  int lsb = *sp & 0x0f;
+
+                  *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
+                      | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
+                  sp++;
+               }
+            }
+
+            else if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp++;
+               }
+            }
+
+            else if (row_info->bit_depth == 16)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+               }
+            }
+            break;
+         }
+
+         default:
+            break;
+      }
+   }
+}
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* Encode the alpha channel to the output gamma (the input channel is always
+ * linear.)  Called only with color types that have an alpha channel.  Needs the
+ * from_1 tables.
+ */
+static void
+png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
+{
+   png_uint_32 row_width = row_info->width;
+
+   png_debug(1, "in png_do_encode_alpha");
+
+   if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep table = png_ptr->gamma_from_1;
+
+         if (table != NULL)
+         {
+            int step = (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
+
+            /* The alpha channel is the last component: */
+            row += step - 1;
+
+            for (; row_width > 0; --row_width, row += step)
+               *row = table[*row];
+
+            return;
+         }
+      }
+
+      else if (row_info->bit_depth == 16)
+      {
+         png_uint_16pp table = png_ptr->gamma_16_from_1;
+         int gamma_shift = png_ptr->gamma_shift;
+
+         if (table != NULL)
+         {
+            int step = (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
+
+            /* The alpha channel is the last component: */
+            row += step - 2;
+
+            for (; row_width > 0; --row_width, row += step)
+            {
+               png_uint_16 v;
+
+               v = table[*(row + 1) >> gamma_shift][*row];
+               *row = (png_byte)((v >> 8) & 0xff);
+               *(row + 1) = (png_byte)(v & 0xff);
+            }
+
+            return;
+         }
+      }
+   }
+
+   /* Only get to here if called with a weird row_info; no harm has been done,
+    * so just issue a warning.
+    */
+   png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
+}
+#endif
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expands a palette row to an RGB or RGBA row depending
+ * upon whether you supply trans and num_trans.
+ */
+static void
+png_do_expand_palette(png_structrp png_ptr, png_row_infop row_info,
+    png_bytep row, png_const_colorp palette, png_const_bytep trans_alpha,
+    int num_trans)
+{
+   int shift, value;
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_expand_palette");
+
+   if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (row_info->bit_depth < 8)
+      {
+         switch (row_info->bit_depth)
+         {
+            case 1:
+            {
+               sp = row + (size_t)((row_width - 1) >> 3);
+               dp = row + (size_t)row_width - 1;
+               shift = 7 - (int)((row_width + 7) & 0x07);
+               for (i = 0; i < row_width; i++)
+               {
+                  if ((*sp >> shift) & 0x01)
+                     *dp = 1;
+
+                  else
+                     *dp = 0;
+
+                  if (shift == 7)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift++;
+
+                  dp--;
+               }
+               break;
+            }
+
+            case 2:
+            {
+               sp = row + (size_t)((row_width - 1) >> 2);
+               dp = row + (size_t)row_width - 1;
+               shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x03;
+                  *dp = (png_byte)value;
+                  if (shift == 6)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift += 2;
+
+                  dp--;
+               }
+               break;
+            }
+
+            case 4:
+            {
+               sp = row + (size_t)((row_width - 1) >> 1);
+               dp = row + (size_t)row_width - 1;
+               shift = (int)((row_width & 0x01) << 2);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x0f;
+                  *dp = (png_byte)value;
+                  if (shift == 4)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift += 4;
+
+                  dp--;
+               }
+               break;
+            }
+
+            default:
+               break;
+         }
+         row_info->bit_depth = 8;
+         row_info->pixel_depth = 8;
+         row_info->rowbytes = row_width;
+      }
+
+      if (row_info->bit_depth == 8)
+      {
+         {
+            if (num_trans > 0)
+            {
+               sp = row + (size_t)row_width - 1;
+               dp = row + ((size_t)row_width << 2) - 1;
+
+               i = 0;
+#ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
+               if (png_ptr->riffled_palette != NULL)
+               {
+                  /* The RGBA optimization works with png_ptr->bit_depth == 8
+                   * but sometimes row_info->bit_depth has been changed to 8.
+                   * In these cases, the palette hasn't been riffled.
+                   */
+                  i = png_do_expand_palette_rgba8_neon(png_ptr, row_info, row,
+                      &sp, &dp);
+               }
+#else
+               PNG_UNUSED(png_ptr)
+#endif
+
+               for (; i < row_width; i++)
+               {
+                  if ((int)(*sp) >= num_trans)
+                     *dp-- = 0xff;
+                  else
+                     *dp-- = trans_alpha[*sp];
+                  *dp-- = palette[*sp].blue;
+                  *dp-- = palette[*sp].green;
+                  *dp-- = palette[*sp].red;
+                  sp--;
+               }
+               row_info->bit_depth = 8;
+               row_info->pixel_depth = 32;
+               row_info->rowbytes = row_width * 4;
+               row_info->color_type = 6;
+               row_info->channels = 4;
+            }
+
+            else
+            {
+               sp = row + (size_t)row_width - 1;
+               dp = row + (size_t)(row_width * 3) - 1;
+               i = 0;
+#ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
+               i = png_do_expand_palette_rgb8_neon(png_ptr, row_info, row,
+                   &sp, &dp);
+#else
+               PNG_UNUSED(png_ptr)
+#endif
+
+               for (; i < row_width; i++)
+               {
+                  *dp-- = palette[*sp].blue;
+                  *dp-- = palette[*sp].green;
+                  *dp-- = palette[*sp].red;
+                  sp--;
+               }
+
+               row_info->bit_depth = 8;
+               row_info->pixel_depth = 24;
+               row_info->rowbytes = row_width * 3;
+               row_info->color_type = 2;
+               row_info->channels = 3;
+            }
+         }
+      }
+   }
+}
+
+/* If the bit depth < 8, it is expanded to 8.  Also, if the already
+ * expanded transparency value is supplied, an alpha channel is built.
+ */
+static void
+png_do_expand(png_row_infop row_info, png_bytep row,
+    png_const_color_16p trans_color)
+{
+   int shift, value;
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_expand");
+
+   if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      unsigned int gray = trans_color != NULL ? trans_color->gray : 0;
+
+      if (row_info->bit_depth < 8)
+      {
+         switch (row_info->bit_depth)
+         {
+            case 1:
+            {
+               gray = (gray & 0x01) * 0xff;
+               sp = row + (size_t)((row_width - 1) >> 3);
+               dp = row + (size_t)row_width - 1;
+               shift = 7 - (int)((row_width + 7) & 0x07);
+               for (i = 0; i < row_width; i++)
+               {
+                  if ((*sp >> shift) & 0x01)
+                     *dp = 0xff;
+
+                  else
+                     *dp = 0;
+
+                  if (shift == 7)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift++;
+
+                  dp--;
+               }
+               break;
+            }
+
+            case 2:
+            {
+               gray = (gray & 0x03) * 0x55;
+               sp = row + (size_t)((row_width - 1) >> 2);
+               dp = row + (size_t)row_width - 1;
+               shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x03;
+                  *dp = (png_byte)(value | (value << 2) | (value << 4) |
+                     (value << 6));
+                  if (shift == 6)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift += 2;
+
+                  dp--;
+               }
+               break;
+            }
+
+            case 4:
+            {
+               gray = (gray & 0x0f) * 0x11;
+               sp = row + (size_t)((row_width - 1) >> 1);
+               dp = row + (size_t)row_width - 1;
+               shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x0f;
+                  *dp = (png_byte)(value | (value << 4));
+                  if (shift == 4)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift = 4;
+
+                  dp--;
+               }
+               break;
+            }
+
+            default:
+               break;
+         }
+
+         row_info->bit_depth = 8;
+         row_info->pixel_depth = 8;
+         row_info->rowbytes = row_width;
+      }
+
+      if (trans_color != NULL)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            gray = gray & 0xff;
+            sp = row + (size_t)row_width - 1;
+            dp = row + ((size_t)row_width << 1) - 1;
+
+            for (i = 0; i < row_width; i++)
+            {
+               if ((*sp & 0xffU) == gray)
+                  *dp-- = 0;
+
+               else
+                  *dp-- = 0xff;
+
+               *dp-- = *sp--;
+            }
+         }
+
+         else if (row_info->bit_depth == 16)
+         {
+            unsigned int gray_high = (gray >> 8) & 0xff;
+            unsigned int gray_low = gray & 0xff;
+            sp = row + row_info->rowbytes - 1;
+            dp = row + (row_info->rowbytes << 1) - 1;
+            for (i = 0; i < row_width; i++)
+            {
+               if ((*(sp - 1) & 0xffU) == gray_high &&
+                   (*(sp) & 0xffU) == gray_low)
+               {
+                  *dp-- = 0;
+                  *dp-- = 0;
+               }
+
+               else
+               {
+                  *dp-- = 0xff;
+                  *dp-- = 0xff;
+               }
+
+               *dp-- = *sp--;
+               *dp-- = *sp--;
+            }
+         }
+
+         row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+         row_info->channels = 2;
+         row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+             row_width);
+      }
+   }
+   else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
+       trans_color != NULL)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         png_byte red = (png_byte)(trans_color->red & 0xff);
+         png_byte green = (png_byte)(trans_color->green & 0xff);
+         png_byte blue = (png_byte)(trans_color->blue & 0xff);
+         sp = row + (size_t)row_info->rowbytes - 1;
+         dp = row + ((size_t)row_width << 2) - 1;
+         for (i = 0; i < row_width; i++)
+         {
+            if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
+               *dp-- = 0;
+
+            else
+               *dp-- = 0xff;
+
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+         }
+      }
+      else if (row_info->bit_depth == 16)
+      {
+         png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
+         png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
+         png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
+         png_byte red_low = (png_byte)(trans_color->red & 0xff);
+         png_byte green_low = (png_byte)(trans_color->green & 0xff);
+         png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
+         sp = row + row_info->rowbytes - 1;
+         dp = row + ((size_t)row_width << 3) - 1;
+         for (i = 0; i < row_width; i++)
+         {
+            if (*(sp - 5) == red_high &&
+                *(sp - 4) == red_low &&
+                *(sp - 3) == green_high &&
+                *(sp - 2) == green_low &&
+                *(sp - 1) == blue_high &&
+                *(sp    ) == blue_low)
+            {
+               *dp-- = 0;
+               *dp-- = 0;
+            }
+
+            else
+            {
+               *dp-- = 0xff;
+               *dp-- = 0xff;
+            }
+
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+         }
+      }
+      row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+      row_info->channels = 4;
+      row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+   }
+}
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* If the bit depth is 8 and the color type is not a palette type expand the
+ * whole row to 16 bits.  Has no effect otherwise.
+ */
+static void
+png_do_expand_16(png_row_infop row_info, png_bytep row)
+{
+   if (row_info->bit_depth == 8 &&
+      row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      /* The row have a sequence of bytes containing [0..255] and we need
+       * to turn it into another row containing [0..65535], to do this we
+       * calculate:
+       *
+       *  (input / 255) * 65535
+       *
+       *  Which happens to be exactly input * 257 and this can be achieved
+       *  simply by byte replication in place (copying backwards).
+       */
+      png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
+      png_byte *dp = sp + row_info->rowbytes;  /* destination, end + 1 */
+      while (dp > sp)
+      {
+         dp[-2] = dp[-1] = *--sp; dp -= 2;
+      }
+
+      row_info->rowbytes *= 2;
+      row_info->bit_depth = 16;
+      row_info->pixel_depth = (png_byte)(row_info->channels * 16);
+   }
+}
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+static void
+png_do_quantize(png_row_infop row_info, png_bytep row,
+    png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
+{
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_quantize");
+
+   if (row_info->bit_depth == 8)
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup)
+      {
+         int r, g, b, p;
+         sp = row;
+         dp = row;
+         for (i = 0; i < row_width; i++)
+         {
+            r = *sp++;
+            g = *sp++;
+            b = *sp++;
+
+            /* This looks real messy, but the compiler will reduce
+             * it down to a reasonable formula.  For example, with
+             * 5 bits per color, we get:
+             * p = (((r >> 3) & 0x1f) << 10) |
+             *    (((g >> 3) & 0x1f) << 5) |
+             *    ((b >> 3) & 0x1f);
+             */
+            p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
+                ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
+                (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
+                (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
+                ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
+                (PNG_QUANTIZE_BLUE_BITS)) |
+                ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
+                ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
+
+            *dp++ = palette_lookup[p];
+         }
+
+         row_info->color_type = PNG_COLOR_TYPE_PALETTE;
+         row_info->channels = 1;
+         row_info->pixel_depth = row_info->bit_depth;
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+         palette_lookup != NULL)
+      {
+         int r, g, b, p;
+         sp = row;
+         dp = row;
+         for (i = 0; i < row_width; i++)
+         {
+            r = *sp++;
+            g = *sp++;
+            b = *sp++;
+            sp++;
+
+            p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
+                ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
+                (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
+                (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
+                ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
+                (PNG_QUANTIZE_BLUE_BITS)) |
+                ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
+                ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
+
+            *dp++ = palette_lookup[p];
+         }
+
+         row_info->color_type = PNG_COLOR_TYPE_PALETTE;
+         row_info->channels = 1;
+         row_info->pixel_depth = row_info->bit_depth;
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+         quantize_lookup)
+      {
+         sp = row;
+
+         for (i = 0; i < row_width; i++, sp++)
+         {
+            *sp = quantize_lookup[*sp];
+         }
+      }
+   }
+}
+#endif /* READ_QUANTIZE */
+
+/* Transform the row.  The order of transformations is significant,
+ * and is very touchy.  If you add a transformation, take care to
+ * decide how it fits in with the other transformations here.
+ */
+void /* PRIVATE */
+png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
+{
+   png_debug(1, "in png_do_read_transformations");
+
+   if (png_ptr->row_buf == NULL)
+   {
+      /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
+       * error is incredibly rare and incredibly easy to debug without this
+       * information.
+       */
+      png_error(png_ptr, "NULL row buffer");
+   }
+
+   /* The following is debugging; prior to 1.5.4 the code was never compiled in;
+    * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
+    * PNG_WARN_UNINITIALIZED_ROW removed.  In 1.6 the new flag is set only for
+    * all transformations, however in practice the ROW_INIT always gets done on
+    * demand, if necessary.
+    */
+   if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
+       (png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+   {
+      /* Application has failed to call either png_read_start_image() or
+       * png_read_update_info() after setting transforms that expand pixels.
+       * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
+       */
+      png_error(png_ptr, "Uninitialized row");
+   }
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+#ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
+         if ((png_ptr->num_trans > 0) && (png_ptr->bit_depth == 8))
+         {
+            if (png_ptr->riffled_palette == NULL)
+            {
+               /* Initialize the accelerated palette expansion. */
+               png_ptr->riffled_palette =
+                   (png_bytep)png_malloc(png_ptr, 256 * 4);
+               png_riffle_palette_neon(png_ptr);
+            }
+         }
+#endif
+         png_do_expand_palette(png_ptr, row_info, png_ptr->row_buf + 1,
+             png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
+      }
+
+      else
+      {
+         if (png_ptr->num_trans != 0 &&
+             (png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
+            png_do_expand(row_info, png_ptr->row_buf + 1,
+                &(png_ptr->trans_color));
+
+         else
+            png_do_expand(row_info, png_ptr->row_buf + 1, NULL);
+      }
+   }
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) == 0 &&
+       (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+       row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+          0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+   {
+      int rgb_error =
+          png_do_rgb_to_gray(png_ptr, row_info,
+              png_ptr->row_buf + 1);
+
+      if (rgb_error != 0)
+      {
+         png_ptr->rgb_to_gray_status=1;
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_WARN)
+            png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_ERR)
+            png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+      }
+   }
+#endif
+
+/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
+ *
+ *   In most cases, the "simple transparency" should be done prior to doing
+ *   gray-to-RGB, or you will have to test 3x as many bytes to check if a
+ *   pixel is transparent.  You would also need to make sure that the
+ *   transparency information is upgraded to RGB.
+ *
+ *   To summarize, the current flow is:
+ *   - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
+ *                                   with background "in place" if transparent,
+ *                                   convert to RGB if necessary
+ *   - Gray + alpha -> composite with gray background and remove alpha bytes,
+ *                                   convert to RGB if necessary
+ *
+ *   To support RGB backgrounds for gray images we need:
+ *   - Gray + simple transparency -> convert to RGB + simple transparency,
+ *                                   compare 3 or 6 bytes and composite with
+ *                                   background "in place" if transparent
+ *                                   (3x compare/pixel compared to doing
+ *                                   composite with gray bkgrnd)
+ *   - Gray + alpha -> convert to RGB + alpha, composite with background and
+ *                                   remove alpha bytes (3x float
+ *                                   operations/pixel compared with composite
+ *                                   on gray background)
+ *
+ *  Greg's change will do this.  The reason it wasn't done before is for
+ *  performance, as this increases the per-pixel operations.  If we would check
+ *  in advance if the background was gray or RGB, and position the gray-to-RGB
+ *  transform appropriately, then it would save a lot of work/time.
+ */
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   /* If gray -> RGB, do so now only if background is non-gray; else do later
+    * for performance reasons
+    */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) == 0)
+      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+      png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   if ((png_ptr->transformations & PNG_GAMMA) != 0 &&
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+      /* Because RGB_TO_GRAY does the gamma transform. */
+      (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0 &&
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+      /* Because PNG_COMPOSE does the gamma transform if there is something to
+       * do (if there is an alpha channel or transparency.)
+       */
+       !((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       ((png_ptr->num_trans != 0) ||
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) &&
+#endif
+      /* Because png_init_read_transformations transforms the palette, unless
+       * RGB_TO_GRAY will do the transform.
+       */
+       (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
+      png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+       row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+          0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+   if ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+       (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+   if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
+      png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+   /* There is no harm in doing both of these because only one has any effect,
+    * by putting the 'scale' option first if the app asks for scale (either by
+    * calling the API or in a TRANSFORM flag) this is what happens.
+    */
+   if ((png_ptr->transformations & PNG_16_TO_8) != 0)
+      png_do_chop(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
+   {
+      png_do_quantize(row_info, png_ptr->row_buf + 1,
+          png_ptr->palette_lookup, png_ptr->quantize_index);
+
+      if (row_info->rowbytes == 0)
+         png_error(png_ptr, "png_do_quantize returned rowbytes=0");
+   }
+#endif /* READ_QUANTIZE */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   /* Do the expansion now, after all the arithmetic has been done.  Notice
+    * that previous transformations can handle the PNG_EXPAND_16 flag if this
+    * is efficient (particularly true in the case of gamma correction, where
+    * better accuracy results faster!)
+    */
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
+      png_do_expand_16(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   /* NOTE: moved here in 1.5.4 (from much later in this list.) */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) != 0)
+      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_INVERT_SUPPORTED
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+      png_do_invert(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+      png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
+      png_do_unshift(row_info, png_ptr->row_buf + 1,
+          &(png_ptr->shift));
+#endif
+
+#ifdef PNG_READ_PACK_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACK) != 0)
+      png_do_unpack(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   /* Added at libpng-1.5.10 */
+   if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+       png_ptr->num_palette_max >= 0)
+      png_do_check_palette_indexes(png_ptr, row_info);
+#endif
+
+#ifdef PNG_READ_BGR_SUPPORTED
+   if ((png_ptr->transformations & PNG_BGR) != 0)
+      png_do_bgr(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+      png_do_packswap(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
+      png_do_read_filler(row_info, png_ptr->row_buf + 1,
+          (png_uint_32)png_ptr->filler, png_ptr->flags);
+#endif
+
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
+      png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+#ifdef PNG_READ_SWAP_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+      png_do_swap(row_info, png_ptr->row_buf + 1);
+#endif
+#endif
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+   {
+      if (png_ptr->read_user_transform_fn != NULL)
+         (*(png_ptr->read_user_transform_fn)) /* User read transform function */
+             (png_ptr,     /* png_ptr */
+             row_info,     /* row_info: */
+                /*  png_uint_32 width;       width of row */
+                /*  size_t rowbytes;         number of bytes in row */
+                /*  png_byte color_type;     color type of pixels */
+                /*  png_byte bit_depth;      bit depth of samples */
+                /*  png_byte channels;       number of channels (1-4) */
+                /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
+             png_ptr->row_buf + 1);    /* start of pixel data for row */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+      if (png_ptr->user_transform_depth != 0)
+         row_info->bit_depth = png_ptr->user_transform_depth;
+
+      if (png_ptr->user_transform_channels != 0)
+         row_info->channels = png_ptr->user_transform_channels;
+#endif
+      row_info->pixel_depth = (png_byte)(row_info->bit_depth *
+          row_info->channels);
+
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
+   }
+#endif
+}
+
+#endif /* READ_TRANSFORMS */
+#endif /* READ */
diff --git a/extern/libpng/pngrutil.c b/extern/libpng/pngrutil.c
new file mode 100644
index 0000000000..d5fa08c397
--- /dev/null
+++ b/extern/libpng/pngrutil.c
@@ -0,0 +1,4681 @@
+
+/* pngrutil.c - utilities to read a PNG file
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file contains routines that are only called from within
+ * libpng itself during the course of reading an image.
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+png_uint_32 PNGAPI
+png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
+{
+   png_uint_32 uval = png_get_uint_32(buf);
+
+   if (uval > PNG_UINT_31_MAX)
+      png_error(png_ptr, "PNG unsigned integer out of range");
+
+   return (uval);
+}
+
+#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
+/* The following is a variation on the above for use with the fixed
+ * point values used for gAMA and cHRM.  Instead of png_error it
+ * issues a warning and returns (-1) - an invalid value because both
+ * gAMA and cHRM use *unsigned* integers for fixed point values.
+ */
+#define PNG_FIXED_ERROR (-1)
+
+static png_fixed_point /* PRIVATE */
+png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
+{
+   png_uint_32 uval = png_get_uint_32(buf);
+
+   if (uval <= PNG_UINT_31_MAX)
+      return (png_fixed_point)uval; /* known to be in range */
+
+   /* The caller can turn off the warning by passing NULL. */
+   if (png_ptr != NULL)
+      png_warning(png_ptr, "PNG fixed point integer out of range");
+
+   return PNG_FIXED_ERROR;
+}
+#endif
+
+#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
+/* NOTE: the read macros will obscure these definitions, so that if
+ * PNG_USE_READ_MACROS is set the library will not use them internally,
+ * but the APIs will still be available externally.
+ *
+ * The parentheses around "PNGAPI function_name" in the following three
+ * functions are necessary because they allow the macros to co-exist with
+ * these (unused but exported) functions.
+ */
+
+/* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
+png_uint_32 (PNGAPI
+png_get_uint_32)(png_const_bytep buf)
+{
+   png_uint_32 uval =
+       ((png_uint_32)(*(buf    )) << 24) +
+       ((png_uint_32)(*(buf + 1)) << 16) +
+       ((png_uint_32)(*(buf + 2)) <<  8) +
+       ((png_uint_32)(*(buf + 3))      ) ;
+
+   return uval;
+}
+
+/* Grab a signed 32-bit integer from a buffer in big-endian format.  The
+ * data is stored in the PNG file in two's complement format and there
+ * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
+ * the following code does a two's complement to native conversion.
+ */
+png_int_32 (PNGAPI
+png_get_int_32)(png_const_bytep buf)
+{
+   png_uint_32 uval = png_get_uint_32(buf);
+   if ((uval & 0x80000000) == 0) /* non-negative */
+      return (png_int_32)uval;
+
+   uval = (uval ^ 0xffffffff) + 1;  /* 2's complement: -x = ~x+1 */
+   if ((uval & 0x80000000) == 0) /* no overflow */
+      return -(png_int_32)uval;
+   /* The following has to be safe; this function only gets called on PNG data
+    * and if we get here that data is invalid.  0 is the most safe value and
+    * if not then an attacker would surely just generate a PNG with 0 instead.
+    */
+   return 0;
+}
+
+/* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
+png_uint_16 (PNGAPI
+png_get_uint_16)(png_const_bytep buf)
+{
+   /* ANSI-C requires an int value to accommodate at least 16 bits so this
+    * works and allows the compiler not to worry about possible narrowing
+    * on 32-bit systems.  (Pre-ANSI systems did not make integers smaller
+    * than 16 bits either.)
+    */
+   unsigned int val =
+       ((unsigned int)(*buf) << 8) +
+       ((unsigned int)(*(buf + 1)));
+
+   return (png_uint_16)val;
+}
+
+#endif /* READ_INT_FUNCTIONS */
+
+/* Read and check the PNG file signature */
+void /* PRIVATE */
+png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
+{
+   size_t num_checked, num_to_check;
+
+   /* Exit if the user application does not expect a signature. */
+   if (png_ptr->sig_bytes >= 8)
+      return;
+
+   num_checked = png_ptr->sig_bytes;
+   num_to_check = 8 - num_checked;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
+#endif
+
+   /* The signature must be serialized in a single I/O call. */
+   png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
+   png_ptr->sig_bytes = 8;
+
+   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
+   {
+      if (num_checked < 4 &&
+          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
+         png_error(png_ptr, "Not a PNG file");
+      else
+         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+   }
+   if (num_checked < 3)
+      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
+/* Read the chunk header (length + type name).
+ * Put the type name into png_ptr->chunk_name, and return the length.
+ */
+png_uint_32 /* PRIVATE */
+png_read_chunk_header(png_structrp png_ptr)
+{
+   png_byte buf[8];
+   png_uint_32 length;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
+#endif
+
+   /* Read the length and the chunk name.
+    * This must be performed in a single I/O call.
+    */
+   png_read_data(png_ptr, buf, 8);
+   length = png_get_uint_31(png_ptr, buf);
+
+   /* Put the chunk name into png_ptr->chunk_name. */
+   png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
+
+   png_debug2(0, "Reading %lx chunk, length = %lu",
+       (unsigned long)png_ptr->chunk_name, (unsigned long)length);
+
+   /* Reset the crc and run it over the chunk name. */
+   png_reset_crc(png_ptr);
+   png_calculate_crc(png_ptr, buf + 4, 4);
+
+   /* Check to see if chunk name is valid. */
+   png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+
+   /* Check for too-large chunk length */
+   png_check_chunk_length(png_ptr, length);
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
+#endif
+
+   return length;
+}
+
+/* Read data, and (optionally) run it through the CRC. */
+void /* PRIVATE */
+png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_read_data(png_ptr, buf, length);
+   png_calculate_crc(png_ptr, buf, length);
+}
+
+/* Optionally skip data and then check the CRC.  Depending on whether we
+ * are reading an ancillary or critical chunk, and how the program has set
+ * things up, we may calculate the CRC on the data and print a message.
+ * Returns '1' if there was a CRC error, '0' otherwise.
+ */
+int /* PRIVATE */
+png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
+{
+   /* The size of the local buffer for inflate is a good guess as to a
+    * reasonable size to use for buffering reads from the application.
+    */
+   while (skip > 0)
+   {
+      png_uint_32 len;
+      png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
+
+      len = (sizeof tmpbuf);
+      if (len > skip)
+         len = skip;
+      skip -= len;
+
+      png_crc_read(png_ptr, tmpbuf, len);
+   }
+
+   if (png_crc_error(png_ptr) != 0)
+   {
+      if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ?
+          (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 :
+          (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
+      {
+         png_chunk_warning(png_ptr, "CRC error");
+      }
+
+      else
+         png_chunk_error(png_ptr, "CRC error");
+
+      return (1);
+   }
+
+   return (0);
+}
+
+/* Compare the CRC stored in the PNG file with that calculated by libpng from
+ * the data it has read thus far.
+ */
+int /* PRIVATE */
+png_crc_error(png_structrp png_ptr)
+{
+   png_byte crc_bytes[4];
+   png_uint_32 crc;
+   int need_crc = 1;
+
+   if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
+          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
+         need_crc = 0;
+   }
+
+   else /* critical */
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
+         need_crc = 0;
+   }
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
+#endif
+
+   /* The chunk CRC must be serialized in a single I/O call. */
+   png_read_data(png_ptr, crc_bytes, 4);
+
+   if (need_crc != 0)
+   {
+      crc = png_get_uint_32(crc_bytes);
+      return ((int)(crc != png_ptr->crc));
+   }
+
+   else
+      return (0);
+}
+
+#if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
+    defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
+    defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
+    defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+/* Manage the read buffer; this simply reallocates the buffer if it is not small
+ * enough (or if it is not allocated).  The routine returns a pointer to the
+ * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
+ * it will call png_error (via png_malloc) on failure.  (warn == 2 means
+ * 'silent').
+ */
+static png_bytep
+png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
+{
+   png_bytep buffer = png_ptr->read_buffer;
+
+   if (buffer != NULL && new_size > png_ptr->read_buffer_size)
+   {
+      png_ptr->read_buffer = NULL;
+      png_ptr->read_buffer = NULL;
+      png_ptr->read_buffer_size = 0;
+      png_free(png_ptr, buffer);
+      buffer = NULL;
+   }
+
+   if (buffer == NULL)
+   {
+      buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
+
+      if (buffer != NULL)
+      {
+         memset(buffer, 0, new_size); /* just in case */
+         png_ptr->read_buffer = buffer;
+         png_ptr->read_buffer_size = new_size;
+      }
+
+      else if (warn < 2) /* else silent */
+      {
+         if (warn != 0)
+             png_chunk_warning(png_ptr, "insufficient memory to read chunk");
+
+         else
+             png_chunk_error(png_ptr, "insufficient memory to read chunk");
+      }
+   }
+
+   return buffer;
+}
+#endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
+
+/* png_inflate_claim: claim the zstream for some nefarious purpose that involves
+ * decompression.  Returns Z_OK on success, else a zlib error code.  It checks
+ * the owner but, in final release builds, just issues a warning if some other
+ * chunk apparently owns the stream.  Prior to release it does a png_error.
+ */
+static int
+png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
+{
+   if (png_ptr->zowner != 0)
+   {
+      char msg[64];
+
+      PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
+      /* So the message that results is "<chunk> using zstream"; this is an
+       * internal error, but is very useful for debugging.  i18n requirements
+       * are minimal.
+       */
+      (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
+#if PNG_RELEASE_BUILD
+      png_chunk_warning(png_ptr, msg);
+      png_ptr->zowner = 0;
+#else
+      png_chunk_error(png_ptr, msg);
+#endif
+   }
+
+   /* Implementation note: unlike 'png_deflate_claim' this internal function
+    * does not take the size of the data as an argument.  Some efficiency could
+    * be gained by using this when it is known *if* the zlib stream itself does
+    * not record the number; however, this is an illusion: the original writer
+    * of the PNG may have selected a lower window size, and we really must
+    * follow that because, for systems with with limited capabilities, we
+    * would otherwise reject the application's attempts to use a smaller window
+    * size (zlib doesn't have an interface to say "this or lower"!).
+    *
+    * inflateReset2 was added to zlib 1.2.4; before this the window could not be
+    * reset, therefore it is necessary to always allocate the maximum window
+    * size with earlier zlibs just in case later compressed chunks need it.
+    */
+   {
+      int ret; /* zlib return code */
+#if ZLIB_VERNUM >= 0x1240
+      int window_bits = 0;
+
+# if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
+      if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
+          PNG_OPTION_ON)
+      {
+         window_bits = 15;
+         png_ptr->zstream_start = 0; /* fixed window size */
+      }
+
+      else
+      {
+         png_ptr->zstream_start = 1;
+      }
+# endif
+
+#endif /* ZLIB_VERNUM >= 0x1240 */
+
+      /* Set this for safety, just in case the previous owner left pointers to
+       * memory allocations.
+       */
+      png_ptr->zstream.next_in = NULL;
+      png_ptr->zstream.avail_in = 0;
+      png_ptr->zstream.next_out = NULL;
+      png_ptr->zstream.avail_out = 0;
+
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+      {
+#if ZLIB_VERNUM >= 0x1240
+         ret = inflateReset2(&png_ptr->zstream, window_bits);
+#else
+         ret = inflateReset(&png_ptr->zstream);
+#endif
+      }
+
+      else
+      {
+#if ZLIB_VERNUM >= 0x1240
+         ret = inflateInit2(&png_ptr->zstream, window_bits);
+#else
+         ret = inflateInit(&png_ptr->zstream);
+#endif
+
+         if (ret == Z_OK)
+            png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
+      }
+
+#if ZLIB_VERNUM >= 0x1290 && \
+   defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32)
+      if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON)
+         /* Turn off validation of the ADLER32 checksum in IDAT chunks */
+         ret = inflateValidate(&png_ptr->zstream, 0);
+#endif
+
+      if (ret == Z_OK)
+         png_ptr->zowner = owner;
+
+      else
+         png_zstream_error(png_ptr, ret);
+
+      return ret;
+   }
+
+#ifdef window_bits
+# undef window_bits
+#endif
+}
+
+#if ZLIB_VERNUM >= 0x1240
+/* Handle the start of the inflate stream if we called inflateInit2(strm,0);
+ * in this case some zlib versions skip validation of the CINFO field and, in
+ * certain circumstances, libpng may end up displaying an invalid image, in
+ * contrast to implementations that call zlib in the normal way (e.g. libpng
+ * 1.5).
+ */
+int /* PRIVATE */
+png_zlib_inflate(png_structrp png_ptr, int flush)
+{
+   if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0)
+   {
+      if ((*png_ptr->zstream.next_in >> 4) > 7)
+      {
+         png_ptr->zstream.msg = "invalid window size (libpng)";
+         return Z_DATA_ERROR;
+      }
+
+      png_ptr->zstream_start = 0;
+   }
+
+   return inflate(&png_ptr->zstream, flush);
+}
+#endif /* Zlib >= 1.2.4 */
+
+#ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
+#if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
+/* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
+ * allow the caller to do multiple calls if required.  If the 'finish' flag is
+ * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
+ * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
+ * Z_OK or Z_STREAM_END will be returned on success.
+ *
+ * The input and output sizes are updated to the actual amounts of data consumed
+ * or written, not the amount available (as in a z_stream).  The data pointers
+ * are not changed, so the next input is (data+input_size) and the next
+ * available output is (output+output_size).
+ */
+static int
+png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
+    /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
+    /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
+{
+   if (png_ptr->zowner == owner) /* Else not claimed */
+   {
+      int ret;
+      png_alloc_size_t avail_out = *output_size_ptr;
+      png_uint_32 avail_in = *input_size_ptr;
+
+      /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
+       * can't even necessarily handle 65536 bytes) because the type uInt is
+       * "16 bits or more".  Consequently it is necessary to chunk the input to
+       * zlib.  This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
+       * maximum value that can be stored in a uInt.)  It is possible to set
+       * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
+       * a performance advantage, because it reduces the amount of data accessed
+       * at each step and that may give the OS more time to page it in.
+       */
+      png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
+      /* avail_in and avail_out are set below from 'size' */
+      png_ptr->zstream.avail_in = 0;
+      png_ptr->zstream.avail_out = 0;
+
+      /* Read directly into the output if it is available (this is set to
+       * a local buffer below if output is NULL).
+       */
+      if (output != NULL)
+         png_ptr->zstream.next_out = output;
+
+      do
+      {
+         uInt avail;
+         Byte local_buffer[PNG_INFLATE_BUF_SIZE];
+
+         /* zlib INPUT BUFFER */
+         /* The setting of 'avail_in' used to be outside the loop; by setting it
+          * inside it is possible to chunk the input to zlib and simply rely on
+          * zlib to advance the 'next_in' pointer.  This allows arbitrary
+          * amounts of data to be passed through zlib at the unavoidable cost of
+          * requiring a window save (memcpy of up to 32768 output bytes)
+          * every ZLIB_IO_MAX input bytes.
+          */
+         avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
+
+         avail = ZLIB_IO_MAX;
+
+         if (avail_in < avail)
+            avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
+
+         avail_in -= avail;
+         png_ptr->zstream.avail_in = avail;
+
+         /* zlib OUTPUT BUFFER */
+         avail_out += png_ptr->zstream.avail_out; /* not written last time */
+
+         avail = ZLIB_IO_MAX; /* maximum zlib can process */
+
+         if (output == NULL)
+         {
+            /* Reset the output buffer each time round if output is NULL and
+             * make available the full buffer, up to 'remaining_space'
+             */
+            png_ptr->zstream.next_out = local_buffer;
+            if ((sizeof local_buffer) < avail)
+               avail = (sizeof local_buffer);
+         }
+
+         if (avail_out < avail)
+            avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
+
+         png_ptr->zstream.avail_out = avail;
+         avail_out -= avail;
+
+         /* zlib inflate call */
+         /* In fact 'avail_out' may be 0 at this point, that happens at the end
+          * of the read when the final LZ end code was not passed at the end of
+          * the previous chunk of input data.  Tell zlib if we have reached the
+          * end of the output buffer.
+          */
+         ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH :
+             (finish ? Z_FINISH : Z_SYNC_FLUSH));
+      } while (ret == Z_OK);
+
+      /* For safety kill the local buffer pointer now */
+      if (output == NULL)
+         png_ptr->zstream.next_out = NULL;
+
+      /* Claw back the 'size' and 'remaining_space' byte counts. */
+      avail_in += png_ptr->zstream.avail_in;
+      avail_out += png_ptr->zstream.avail_out;
+
+      /* Update the input and output sizes; the updated values are the amount
+       * consumed or written, effectively the inverse of what zlib uses.
+       */
+      if (avail_out > 0)
+         *output_size_ptr -= avail_out;
+
+      if (avail_in > 0)
+         *input_size_ptr -= avail_in;
+
+      /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
+      png_zstream_error(png_ptr, ret);
+      return ret;
+   }
+
+   else
+   {
+      /* This is a bad internal error.  The recovery assigns to the zstream msg
+       * pointer, which is not owned by the caller, but this is safe; it's only
+       * used on errors!
+       */
+      png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
+      return Z_STREAM_ERROR;
+   }
+}
+
+/*
+ * Decompress trailing data in a chunk.  The assumption is that read_buffer
+ * points at an allocated area holding the contents of a chunk with a
+ * trailing compressed part.  What we get back is an allocated area
+ * holding the original prefix part and an uncompressed version of the
+ * trailing part (the malloc area passed in is freed).
+ */
+static int
+png_decompress_chunk(png_structrp png_ptr,
+    png_uint_32 chunklength, png_uint_32 prefix_size,
+    png_alloc_size_t *newlength /* must be initialized to the maximum! */,
+    int terminate /*add a '\0' to the end of the uncompressed data*/)
+{
+   /* TODO: implement different limits for different types of chunk.
+    *
+    * The caller supplies *newlength set to the maximum length of the
+    * uncompressed data, but this routine allocates space for the prefix and
+    * maybe a '\0' terminator too.  We have to assume that 'prefix_size' is
+    * limited only by the maximum chunk size.
+    */
+   png_alloc_size_t limit = PNG_SIZE_MAX;
+
+# ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_malloc_max > 0 &&
+       png_ptr->user_chunk_malloc_max < limit)
+      limit = png_ptr->user_chunk_malloc_max;
+# elif PNG_USER_CHUNK_MALLOC_MAX > 0
+   if (PNG_USER_CHUNK_MALLOC_MAX < limit)
+      limit = PNG_USER_CHUNK_MALLOC_MAX;
+# endif
+
+   if (limit >= prefix_size + (terminate != 0))
+   {
+      int ret;
+
+      limit -= prefix_size + (terminate != 0);
+
+      if (limit < *newlength)
+         *newlength = limit;
+
+      /* Now try to claim the stream. */
+      ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
+
+      if (ret == Z_OK)
+      {
+         png_uint_32 lzsize = chunklength - prefix_size;
+
+         ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
+             /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
+             /* output: */ NULL, newlength);
+
+         if (ret == Z_STREAM_END)
+         {
+            /* Use 'inflateReset' here, not 'inflateReset2' because this
+             * preserves the previously decided window size (otherwise it would
+             * be necessary to store the previous window size.)  In practice
+             * this doesn't matter anyway, because png_inflate will call inflate
+             * with Z_FINISH in almost all cases, so the window will not be
+             * maintained.
+             */
+            if (inflateReset(&png_ptr->zstream) == Z_OK)
+            {
+               /* Because of the limit checks above we know that the new,
+                * expanded, size will fit in a size_t (let alone an
+                * png_alloc_size_t).  Use png_malloc_base here to avoid an
+                * extra OOM message.
+                */
+               png_alloc_size_t new_size = *newlength;
+               png_alloc_size_t buffer_size = prefix_size + new_size +
+                   (terminate != 0);
+               png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
+                   buffer_size));
+
+               if (text != NULL)
+               {
+                  memset(text, 0, buffer_size);
+
+                  ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
+                      png_ptr->read_buffer + prefix_size, &lzsize,
+                      text + prefix_size, newlength);
+
+                  if (ret == Z_STREAM_END)
+                  {
+                     if (new_size == *newlength)
+                     {
+                        if (terminate != 0)
+                           text[prefix_size + *newlength] = 0;
+
+                        if (prefix_size > 0)
+                           memcpy(text, png_ptr->read_buffer, prefix_size);
+
+                        {
+                           png_bytep old_ptr = png_ptr->read_buffer;
+
+                           png_ptr->read_buffer = text;
+                           png_ptr->read_buffer_size = buffer_size;
+                           text = old_ptr; /* freed below */
+                        }
+                     }
+
+                     else
+                     {
+                        /* The size changed on the second read, there can be no
+                         * guarantee that anything is correct at this point.
+                         * The 'msg' pointer has been set to "unexpected end of
+                         * LZ stream", which is fine, but return an error code
+                         * that the caller won't accept.
+                         */
+                        ret = PNG_UNEXPECTED_ZLIB_RETURN;
+                     }
+                  }
+
+                  else if (ret == Z_OK)
+                     ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
+
+                  /* Free the text pointer (this is the old read_buffer on
+                   * success)
+                   */
+                  png_free(png_ptr, text);
+
+                  /* This really is very benign, but it's still an error because
+                   * the extra space may otherwise be used as a Trojan Horse.
+                   */
+                  if (ret == Z_STREAM_END &&
+                      chunklength - prefix_size != lzsize)
+                     png_chunk_benign_error(png_ptr, "extra compressed data");
+               }
+
+               else
+               {
+                  /* Out of memory allocating the buffer */
+                  ret = Z_MEM_ERROR;
+                  png_zstream_error(png_ptr, Z_MEM_ERROR);
+               }
+            }
+
+            else
+            {
+               /* inflateReset failed, store the error message */
+               png_zstream_error(png_ptr, ret);
+               ret = PNG_UNEXPECTED_ZLIB_RETURN;
+            }
+         }
+
+         else if (ret == Z_OK)
+            ret = PNG_UNEXPECTED_ZLIB_RETURN;
+
+         /* Release the claimed stream */
+         png_ptr->zowner = 0;
+      }
+
+      else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
+         ret = PNG_UNEXPECTED_ZLIB_RETURN;
+
+      return ret;
+   }
+
+   else
+   {
+      /* Application/configuration limits exceeded */
+      png_zstream_error(png_ptr, Z_MEM_ERROR);
+      return Z_MEM_ERROR;
+   }
+}
+#endif /* READ_zTXt || READ_iTXt */
+#endif /* READ_COMPRESSED_TEXT */
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+/* Perform a partial read and decompress, producing 'avail_out' bytes and
+ * reading from the current chunk as required.
+ */
+static int
+png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
+    png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
+    int finish)
+{
+   if (png_ptr->zowner == png_ptr->chunk_name)
+   {
+      int ret;
+
+      /* next_in and avail_in must have been initialized by the caller. */
+      png_ptr->zstream.next_out = next_out;
+      png_ptr->zstream.avail_out = 0; /* set in the loop */
+
+      do
+      {
+         if (png_ptr->zstream.avail_in == 0)
+         {
+            if (read_size > *chunk_bytes)
+               read_size = (uInt)*chunk_bytes;
+            *chunk_bytes -= read_size;
+
+            if (read_size > 0)
+               png_crc_read(png_ptr, read_buffer, read_size);
+
+            png_ptr->zstream.next_in = read_buffer;
+            png_ptr->zstream.avail_in = read_size;
+         }
+
+         if (png_ptr->zstream.avail_out == 0)
+         {
+            uInt avail = ZLIB_IO_MAX;
+            if (avail > *out_size)
+               avail = (uInt)*out_size;
+            *out_size -= avail;
+
+            png_ptr->zstream.avail_out = avail;
+         }
+
+         /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
+          * the available output is produced; this allows reading of truncated
+          * streams.
+          */
+         ret = PNG_INFLATE(png_ptr, *chunk_bytes > 0 ?
+             Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
+      }
+      while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
+
+      *out_size += png_ptr->zstream.avail_out;
+      png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
+
+      /* Ensure the error message pointer is always set: */
+      png_zstream_error(png_ptr, ret);
+      return ret;
+   }
+
+   else
+   {
+      png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
+      return Z_STREAM_ERROR;
+   }
+}
+#endif /* READ_iCCP */
+
+/* Read and check the IDHR chunk */
+
+void /* PRIVATE */
+png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[13];
+   png_uint_32 width, height;
+   int bit_depth, color_type, compression_type, filter_type;
+   int interlace_type;
+
+   png_debug(1, "in png_handle_IHDR");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) != 0)
+      png_chunk_error(png_ptr, "out of place");
+
+   /* Check the length */
+   if (length != 13)
+      png_chunk_error(png_ptr, "invalid");
+
+   png_ptr->mode |= PNG_HAVE_IHDR;
+
+   png_crc_read(png_ptr, buf, 13);
+   png_crc_finish(png_ptr, 0);
+
+   width = png_get_uint_31(png_ptr, buf);
+   height = png_get_uint_31(png_ptr, buf + 4);
+   bit_depth = buf[8];
+   color_type = buf[9];
+   compression_type = buf[10];
+   filter_type = buf[11];
+   interlace_type = buf[12];
+
+   /* Set internal variables */
+   png_ptr->width = width;
+   png_ptr->height = height;
+   png_ptr->bit_depth = (png_byte)bit_depth;
+   png_ptr->interlaced = (png_byte)interlace_type;
+   png_ptr->color_type = (png_byte)color_type;
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   png_ptr->filter_type = (png_byte)filter_type;
+#endif
+   png_ptr->compression_type = (png_byte)compression_type;
+
+   /* Find number of channels */
+   switch (png_ptr->color_type)
+   {
+      default: /* invalid, png_set_IHDR calls png_error */
+      case PNG_COLOR_TYPE_GRAY:
+      case PNG_COLOR_TYPE_PALETTE:
+         png_ptr->channels = 1;
+         break;
+
+      case PNG_COLOR_TYPE_RGB:
+         png_ptr->channels = 3;
+         break;
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         png_ptr->channels = 2;
+         break;
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         png_ptr->channels = 4;
+         break;
+   }
+
+   /* Set up other useful info */
+   png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
+   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
+   png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
+   png_debug1(3, "channels = %d", png_ptr->channels);
+   png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
+   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
+       color_type, interlace_type, compression_type, filter_type);
+}
+
+/* Read and check the palette */
+void /* PRIVATE */
+png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_color palette[PNG_MAX_PALETTE_LENGTH];
+   int max_palette_length, num, i;
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+   png_colorp pal_ptr;
+#endif
+
+   png_debug(1, "in png_handle_PLTE");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   /* Moved to before the 'after IDAT' check below because otherwise duplicate
+    * PLTE chunks are potentially ignored (the spec says there shall not be more
+    * than one PLTE, the error is not treated as benign, so this check trumps
+    * the requirement that PLTE appears before IDAT.)
+    */
+   else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0)
+      png_chunk_error(png_ptr, "duplicate");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      /* This is benign because the non-benign error happened before, when an
+       * IDAT was encountered in a color-mapped image with no PLTE.
+       */
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   png_ptr->mode |= PNG_HAVE_PLTE;
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
+      return;
+   }
+
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
+   if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+#endif
+
+   if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
+   {
+      png_crc_finish(png_ptr, length);
+
+      if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+         png_chunk_benign_error(png_ptr, "invalid");
+
+      else
+         png_chunk_error(png_ptr, "invalid");
+
+      return;
+   }
+
+   /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
+   num = (int)length / 3;
+
+   /* If the palette has 256 or fewer entries but is too large for the bit
+    * depth, we don't issue an error, to preserve the behavior of previous
+    * libpng versions. We silently truncate the unused extra palette entries
+    * here.
+    */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      max_palette_length = (1 << png_ptr->bit_depth);
+   else
+      max_palette_length = PNG_MAX_PALETTE_LENGTH;
+
+   if (num > max_palette_length)
+      num = max_palette_length;
+
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+   for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
+   {
+      png_byte buf[3];
+
+      png_crc_read(png_ptr, buf, 3);
+      pal_ptr->red = buf[0];
+      pal_ptr->green = buf[1];
+      pal_ptr->blue = buf[2];
+   }
+#else
+   for (i = 0; i < num; i++)
+   {
+      png_byte buf[3];
+
+      png_crc_read(png_ptr, buf, 3);
+      /* Don't depend upon png_color being any order */
+      palette[i].red = buf[0];
+      palette[i].green = buf[1];
+      palette[i].blue = buf[2];
+   }
+#endif
+
+   /* If we actually need the PLTE chunk (ie for a paletted image), we do
+    * whatever the normal CRC configuration tells us.  However, if we
+    * have an RGB image, the PLTE can be considered ancillary, so
+    * we will act as though it is.
+    */
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#endif
+   {
+      png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3));
+   }
+
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
+   else if (png_crc_error(png_ptr) != 0)  /* Only if we have a CRC error */
+   {
+      /* If we don't want to use the data from an ancillary chunk,
+       * we have two options: an error abort, or a warning and we
+       * ignore the data in this chunk (which should be OK, since
+       * it's considered ancillary for a RGB or RGBA image).
+       *
+       * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
+       * chunk type to determine whether to check the ancillary or the critical
+       * flags.
+       */
+      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0)
+      {
+         if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0)
+            return;
+
+         else
+            png_chunk_error(png_ptr, "CRC error");
+      }
+
+      /* Otherwise, we (optionally) emit a warning and use the chunk. */
+      else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0)
+         png_chunk_warning(png_ptr, "CRC error");
+   }
+#endif
+
+   /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
+    * own copy of the palette.  This has the side effect that when png_start_row
+    * is called (this happens after any call to png_read_update_info) the
+    * info_ptr palette gets changed.  This is extremely unexpected and
+    * confusing.
+    *
+    * Fix this by not sharing the palette in this way.
+    */
+   png_set_PLTE(png_ptr, info_ptr, palette, num);
+
+   /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
+    * IDAT.  Prior to 1.6.0 this was not checked; instead the code merely
+    * checked the apparent validity of a tRNS chunk inserted before PLTE on a
+    * palette PNG.  1.6.0 attempts to rigorously follow the standard and
+    * therefore does a benign error if the erroneous condition is detected *and*
+    * cancels the tRNS if the benign error returns.  The alternative is to
+    * amend the standard since it would be rather hypocritical of the standards
+    * maintainers to ignore it.
+    */
+#ifdef PNG_READ_tRNS_SUPPORTED
+   if (png_ptr->num_trans > 0 ||
+       (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
+   {
+      /* Cancel this because otherwise it would be used if the transforms
+       * require it.  Don't cancel the 'valid' flag because this would prevent
+       * detection of duplicate chunks.
+       */
+      png_ptr->num_trans = 0;
+
+      if (info_ptr != NULL)
+         info_ptr->num_trans = 0;
+
+      png_chunk_benign_error(png_ptr, "tRNS must be after");
+   }
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
+      png_chunk_benign_error(png_ptr, "hIST must be after");
+#endif
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
+      png_chunk_benign_error(png_ptr, "bKGD must be after");
+#endif
+}
+
+void /* PRIVATE */
+png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_debug(1, "in png_handle_IEND");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 ||
+       (png_ptr->mode & PNG_HAVE_IDAT) == 0)
+      png_chunk_error(png_ptr, "out of place");
+
+   png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
+
+   png_crc_finish(png_ptr, length);
+
+   if (length != 0)
+      png_chunk_benign_error(png_ptr, "invalid");
+
+   PNG_UNUSED(info_ptr)
+}
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+void /* PRIVATE */
+png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_fixed_point igamma;
+   png_byte buf[4];
+
+   png_debug(1, "in png_handle_gAMA");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   if (length != 4)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 4);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   igamma = png_get_fixed_point(NULL, buf);
+
+   png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
+   png_colorspace_sync(png_ptr, info_ptr);
+}
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+void /* PRIVATE */
+png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   unsigned int truelen, i;
+   png_byte sample_depth;
+   png_byte buf[4];
+
+   png_debug(1, "in png_handle_sBIT");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      truelen = 3;
+      sample_depth = 8;
+   }
+
+   else
+   {
+      truelen = png_ptr->channels;
+      sample_depth = png_ptr->bit_depth;
+   }
+
+   if (length != truelen || length > 4)
+   {
+      png_chunk_benign_error(png_ptr, "invalid");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
+   png_crc_read(png_ptr, buf, truelen);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   for (i=0; i<truelen; ++i)
+   {
+      if (buf[i] == 0 || buf[i] > sample_depth)
+      {
+         png_chunk_benign_error(png_ptr, "invalid");
+         return;
+      }
+   }
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_ptr->sig_bit.red = buf[0];
+      png_ptr->sig_bit.green = buf[1];
+      png_ptr->sig_bit.blue = buf[2];
+      png_ptr->sig_bit.alpha = buf[3];
+   }
+
+   else
+   {
+      png_ptr->sig_bit.gray = buf[0];
+      png_ptr->sig_bit.red = buf[0];
+      png_ptr->sig_bit.green = buf[0];
+      png_ptr->sig_bit.blue = buf[0];
+      png_ptr->sig_bit.alpha = buf[1];
+   }
+
+   png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
+}
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+void /* PRIVATE */
+png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[32];
+   png_xy xy;
+
+   png_debug(1, "in png_handle_cHRM");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   if (length != 32)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 32);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   xy.whitex = png_get_fixed_point(NULL, buf);
+   xy.whitey = png_get_fixed_point(NULL, buf + 4);
+   xy.redx   = png_get_fixed_point(NULL, buf + 8);
+   xy.redy   = png_get_fixed_point(NULL, buf + 12);
+   xy.greenx = png_get_fixed_point(NULL, buf + 16);
+   xy.greeny = png_get_fixed_point(NULL, buf + 20);
+   xy.bluex  = png_get_fixed_point(NULL, buf + 24);
+   xy.bluey  = png_get_fixed_point(NULL, buf + 28);
+
+   if (xy.whitex == PNG_FIXED_ERROR ||
+       xy.whitey == PNG_FIXED_ERROR ||
+       xy.redx   == PNG_FIXED_ERROR ||
+       xy.redy   == PNG_FIXED_ERROR ||
+       xy.greenx == PNG_FIXED_ERROR ||
+       xy.greeny == PNG_FIXED_ERROR ||
+       xy.bluex  == PNG_FIXED_ERROR ||
+       xy.bluey  == PNG_FIXED_ERROR)
+   {
+      png_chunk_benign_error(png_ptr, "invalid values");
+      return;
+   }
+
+   /* If a colorspace error has already been output skip this chunk */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+      return;
+
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0)
+   {
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
+      png_colorspace_sync(png_ptr, info_ptr);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+   (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
+       1/*prefer cHRM values*/);
+   png_colorspace_sync(png_ptr, info_ptr);
+}
+#endif
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+void /* PRIVATE */
+png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte intent;
+
+   png_debug(1, "in png_handle_sRGB");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   if (length != 1)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, &intent, 1);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* If a colorspace error has already been output skip this chunk */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+      return;
+
+   /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
+    * this.
+    */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0)
+   {
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
+      png_colorspace_sync(png_ptr, info_ptr);
+      png_chunk_benign_error(png_ptr, "too many profiles");
+      return;
+   }
+
+   (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
+   png_colorspace_sync(png_ptr, info_ptr);
+}
+#endif /* READ_sRGB */
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+void /* PRIVATE */
+png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+/* Note: this does not properly handle profiles that are > 64K under DOS */
+{
+   png_const_charp errmsg = NULL; /* error message output, or no error */
+   int finished = 0; /* crc checked */
+
+   png_debug(1, "in png_handle_iCCP");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   /* Consistent with all the above colorspace handling an obviously *invalid*
+    * chunk is just ignored, so does not invalidate the color space.  An
+    * alternative is to set the 'invalid' flags at the start of this routine
+    * and only clear them in they were not set before and all the tests pass.
+    */
+
+   /* The keyword must be at least one character and there is a
+    * terminator (0) byte and the compression method byte, and the
+    * 'zlib' datastream is at least 11 bytes.
+    */
+   if (length < 14)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "too short");
+      return;
+   }
+
+   /* If a colorspace error has already been output skip this chunk */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
+    * this.
+    */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
+   {
+      uInt read_length, keyword_length;
+      char keyword[81];
+
+      /* Find the keyword; the keyword plus separator and compression method
+       * bytes can be at most 81 characters long.
+       */
+      read_length = 81; /* maximum */
+      if (read_length > length)
+         read_length = (uInt)length;
+
+      png_crc_read(png_ptr, (png_bytep)keyword, read_length);
+      length -= read_length;
+
+      /* The minimum 'zlib' stream is assumed to be just the 2 byte header,
+       * 5 bytes minimum 'deflate' stream, and the 4 byte checksum.
+       */
+      if (length < 11)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "too short");
+         return;
+      }
+
+      keyword_length = 0;
+      while (keyword_length < 80 && keyword_length < read_length &&
+         keyword[keyword_length] != 0)
+         ++keyword_length;
+
+      /* TODO: make the keyword checking common */
+      if (keyword_length >= 1 && keyword_length <= 79)
+      {
+         /* We only understand '0' compression - deflate - so if we get a
+          * different value we can't safely decode the chunk.
+          */
+         if (keyword_length+1 < read_length &&
+            keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
+         {
+            read_length -= keyword_length+2;
+
+            if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
+            {
+               Byte profile_header[132]={0};
+               Byte local_buffer[PNG_INFLATE_BUF_SIZE];
+               png_alloc_size_t size = (sizeof profile_header);
+
+               png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
+               png_ptr->zstream.avail_in = read_length;
+               (void)png_inflate_read(png_ptr, local_buffer,
+                   (sizeof local_buffer), &length, profile_header, &size,
+                   0/*finish: don't, because the output is too small*/);
+
+               if (size == 0)
+               {
+                  /* We have the ICC profile header; do the basic header checks.
+                   */
+                  png_uint_32 profile_length = png_get_uint_32(profile_header);
+
+                  if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
+                      keyword, profile_length) != 0)
+                  {
+                     /* The length is apparently ok, so we can check the 132
+                      * byte header.
+                      */
+                     if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
+                         keyword, profile_length, profile_header,
+                         png_ptr->color_type) != 0)
+                     {
+                        /* Now read the tag table; a variable size buffer is
+                         * needed at this point, allocate one for the whole
+                         * profile.  The header check has already validated
+                         * that none of this stuff will overflow.
+                         */
+                        png_uint_32 tag_count =
+                           png_get_uint_32(profile_header + 128);
+                        png_bytep profile = png_read_buffer(png_ptr,
+                            profile_length, 2/*silent*/);
+
+                        if (profile != NULL)
+                        {
+                           memcpy(profile, profile_header,
+                               (sizeof profile_header));
+
+                           size = 12 * tag_count;
+
+                           (void)png_inflate_read(png_ptr, local_buffer,
+                               (sizeof local_buffer), &length,
+                               profile + (sizeof profile_header), &size, 0);
+
+                           /* Still expect a buffer error because we expect
+                            * there to be some tag data!
+                            */
+                           if (size == 0)
+                           {
+                              if (png_icc_check_tag_table(png_ptr,
+                                  &png_ptr->colorspace, keyword, profile_length,
+                                  profile) != 0)
+                              {
+                                 /* The profile has been validated for basic
+                                  * security issues, so read the whole thing in.
+                                  */
+                                 size = profile_length - (sizeof profile_header)
+                                     - 12 * tag_count;
+
+                                 (void)png_inflate_read(png_ptr, local_buffer,
+                                     (sizeof local_buffer), &length,
+                                     profile + (sizeof profile_header) +
+                                     12 * tag_count, &size, 1/*finish*/);
+
+                                 if (length > 0 && !(png_ptr->flags &
+                                     PNG_FLAG_BENIGN_ERRORS_WARN))
+                                    errmsg = "extra compressed data";
+
+                                 /* But otherwise allow extra data: */
+                                 else if (size == 0)
+                                 {
+                                    if (length > 0)
+                                    {
+                                       /* This can be handled completely, so
+                                        * keep going.
+                                        */
+                                       png_chunk_warning(png_ptr,
+                                           "extra compressed data");
+                                    }
+
+                                    png_crc_finish(png_ptr, length);
+                                    finished = 1;
+
+# if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
+                                    /* Check for a match against sRGB */
+                                    png_icc_set_sRGB(png_ptr,
+                                        &png_ptr->colorspace, profile,
+                                        png_ptr->zstream.adler);
+# endif
+
+                                    /* Steal the profile for info_ptr. */
+                                    if (info_ptr != NULL)
+                                    {
+                                       png_free_data(png_ptr, info_ptr,
+                                           PNG_FREE_ICCP, 0);
+
+                                       info_ptr->iccp_name = png_voidcast(char*,
+                                           png_malloc_base(png_ptr,
+                                           keyword_length+1));
+                                       if (info_ptr->iccp_name != NULL)
+                                       {
+                                          memcpy(info_ptr->iccp_name, keyword,
+                                              keyword_length+1);
+                                          info_ptr->iccp_proflen =
+                                              profile_length;
+                                          info_ptr->iccp_profile = profile;
+                                          png_ptr->read_buffer = NULL; /*steal*/
+                                          info_ptr->free_me |= PNG_FREE_ICCP;
+                                          info_ptr->valid |= PNG_INFO_iCCP;
+                                       }
+
+                                       else
+                                       {
+                                          png_ptr->colorspace.flags |=
+                                             PNG_COLORSPACE_INVALID;
+                                          errmsg = "out of memory";
+                                       }
+                                    }
+
+                                    /* else the profile remains in the read
+                                     * buffer which gets reused for subsequent
+                                     * chunks.
+                                     */
+
+                                    if (info_ptr != NULL)
+                                       png_colorspace_sync(png_ptr, info_ptr);
+
+                                    if (errmsg == NULL)
+                                    {
+                                       png_ptr->zowner = 0;
+                                       return;
+                                    }
+                                 }
+                                 if (errmsg == NULL)
+                                    errmsg = png_ptr->zstream.msg;
+                              }
+                              /* else png_icc_check_tag_table output an error */
+                           }
+                           else /* profile truncated */
+                              errmsg = png_ptr->zstream.msg;
+                        }
+
+                        else
+                           errmsg = "out of memory";
+                     }
+
+                     /* else png_icc_check_header output an error */
+                  }
+
+                  /* else png_icc_check_length output an error */
+               }
+
+               else /* profile truncated */
+                  errmsg = png_ptr->zstream.msg;
+
+               /* Release the stream */
+               png_ptr->zowner = 0;
+            }
+
+            else /* png_inflate_claim failed */
+               errmsg = png_ptr->zstream.msg;
+         }
+
+         else
+            errmsg = "bad compression method"; /* or missing */
+      }
+
+      else
+         errmsg = "bad keyword";
+   }
+
+   else
+      errmsg = "too many profiles";
+
+   /* Failure: the reason is in 'errmsg' */
+   if (finished == 0)
+      png_crc_finish(png_ptr, length);
+
+   png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
+   png_colorspace_sync(png_ptr, info_ptr);
+   if (errmsg != NULL) /* else already output */
+      png_chunk_benign_error(png_ptr, errmsg);
+}
+#endif /* READ_iCCP */
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+void /* PRIVATE */
+png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+{
+   png_bytep entry_start, buffer;
+   png_sPLT_t new_palette;
+   png_sPLT_entryp pp;
+   png_uint_32 data_length;
+   int entry_size, i;
+   png_uint_32 skip = 0;
+   png_uint_32 dl;
+   size_t max_dl;
+
+   png_debug(1, "in png_handle_sPLT");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_warning(png_ptr, "No space in chunk cache for sPLT");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (length > 65535U)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "too large to fit in memory");
+      return;
+   }
+#endif
+
+   buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
+   if (buffer == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+
+   /* WARNING: this may break if size_t is less than 32 bits; it is assumed
+    * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
+    * potential breakage point if the types in pngconf.h aren't exactly right.
+    */
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, skip) != 0)
+      return;
+
+   buffer[length] = 0;
+
+   for (entry_start = buffer; *entry_start; entry_start++)
+      /* Empty loop to find end of name */ ;
+
+   ++entry_start;
+
+   /* A sample depth should follow the separator, and we should be on it  */
+   if (length < 2U || entry_start > buffer + (length - 2U))
+   {
+      png_warning(png_ptr, "malformed sPLT chunk");
+      return;
+   }
+
+   new_palette.depth = *entry_start++;
+   entry_size = (new_palette.depth == 8 ? 6 : 10);
+   /* This must fit in a png_uint_32 because it is derived from the original
+    * chunk data length.
+    */
+   data_length = length - (png_uint_32)(entry_start - buffer);
+
+   /* Integrity-check the data length */
+   if ((data_length % (unsigned int)entry_size) != 0)
+   {
+      png_warning(png_ptr, "sPLT chunk has bad length");
+      return;
+   }
+
+   dl = (png_uint_32)(data_length / (unsigned int)entry_size);
+   max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
+
+   if (dl > max_dl)
+   {
+      png_warning(png_ptr, "sPLT chunk too long");
+      return;
+   }
+
+   new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size);
+
+   new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
+       (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry)));
+
+   if (new_palette.entries == NULL)
+   {
+      png_warning(png_ptr, "sPLT chunk requires too much memory");
+      return;
+   }
+
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+   for (i = 0; i < new_palette.nentries; i++)
+   {
+      pp = new_palette.entries + i;
+
+      if (new_palette.depth == 8)
+      {
+         pp->red = *entry_start++;
+         pp->green = *entry_start++;
+         pp->blue = *entry_start++;
+         pp->alpha = *entry_start++;
+      }
+
+      else
+      {
+         pp->red   = png_get_uint_16(entry_start); entry_start += 2;
+         pp->green = png_get_uint_16(entry_start); entry_start += 2;
+         pp->blue  = png_get_uint_16(entry_start); entry_start += 2;
+         pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
+      }
+
+      pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
+   }
+#else
+   pp = new_palette.entries;
+
+   for (i = 0; i < new_palette.nentries; i++)
+   {
+
+      if (new_palette.depth == 8)
+      {
+         pp[i].red   = *entry_start++;
+         pp[i].green = *entry_start++;
+         pp[i].blue  = *entry_start++;
+         pp[i].alpha = *entry_start++;
+      }
+
+      else
+      {
+         pp[i].red   = png_get_uint_16(entry_start); entry_start += 2;
+         pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
+         pp[i].blue  = png_get_uint_16(entry_start); entry_start += 2;
+         pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
+      }
+
+      pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
+   }
+#endif
+
+   /* Discard all chunk data except the name and stash that */
+   new_palette.name = (png_charp)buffer;
+
+   png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
+
+   png_free(png_ptr, new_palette.entries);
+}
+#endif /* READ_sPLT */
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+void /* PRIVATE */
+png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
+
+   png_debug(1, "in png_handle_tRNS");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      png_byte buf[2];
+
+      if (length != 2)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "invalid");
+         return;
+      }
+
+      png_crc_read(png_ptr, buf, 2);
+      png_ptr->num_trans = 1;
+      png_ptr->trans_color.gray = png_get_uint_16(buf);
+   }
+
+   else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+   {
+      png_byte buf[6];
+
+      if (length != 6)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "invalid");
+         return;
+      }
+
+      png_crc_read(png_ptr, buf, length);
+      png_ptr->num_trans = 1;
+      png_ptr->trans_color.red = png_get_uint_16(buf);
+      png_ptr->trans_color.green = png_get_uint_16(buf + 2);
+      png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
+   }
+
+   else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
+      {
+         /* TODO: is this actually an error in the ISO spec? */
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "out of place");
+         return;
+      }
+
+      if (length > (unsigned int) png_ptr->num_palette ||
+         length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
+         length == 0)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "invalid");
+         return;
+      }
+
+      png_crc_read(png_ptr, readbuf, length);
+      png_ptr->num_trans = (png_uint_16)length;
+   }
+
+   else
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid with alpha channel");
+      return;
+   }
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+   {
+      png_ptr->num_trans = 0;
+      return;
+   }
+
+   /* TODO: this is a horrible side effect in the palette case because the
+    * png_struct ends up with a pointer to the tRNS buffer owned by the
+    * png_info.  Fix this.
+    */
+   png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
+       &(png_ptr->trans_color));
+}
+#endif
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+void /* PRIVATE */
+png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   unsigned int truelen;
+   png_byte buf[6];
+   png_color_16 background;
+
+   png_debug(1, "in png_handle_bKGD");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
+       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+       (png_ptr->mode & PNG_HAVE_PLTE) == 0))
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      truelen = 1;
+
+   else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      truelen = 6;
+
+   else
+      truelen = 2;
+
+   if (length != truelen)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, truelen);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* We convert the index value into RGB components so that we can allow
+    * arbitrary RGB values for background when we have transparency, and
+    * so it is easy to determine the RGB values of the background color
+    * from the info_ptr struct.
+    */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      background.index = buf[0];
+
+      if (info_ptr != NULL && info_ptr->num_palette != 0)
+      {
+         if (buf[0] >= info_ptr->num_palette)
+         {
+            png_chunk_benign_error(png_ptr, "invalid index");
+            return;
+         }
+
+         background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
+         background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
+         background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
+      }
+
+      else
+         background.red = background.green = background.blue = 0;
+
+      background.gray = 0;
+   }
+
+   else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
+   {
+      if (png_ptr->bit_depth <= 8)
+      {
+         if (buf[0] != 0 || buf[1] >= (unsigned int)(1 << png_ptr->bit_depth))
+         {
+            png_chunk_benign_error(png_ptr, "invalid gray level");
+            return;
+         }
+      }
+
+      background.index = 0;
+      background.red =
+      background.green =
+      background.blue =
+      background.gray = png_get_uint_16(buf);
+   }
+
+   else
+   {
+      if (png_ptr->bit_depth <= 8)
+      {
+         if (buf[0] != 0 || buf[2] != 0 || buf[4] != 0)
+         {
+            png_chunk_benign_error(png_ptr, "invalid color");
+            return;
+         }
+      }
+
+      background.index = 0;
+      background.red = png_get_uint_16(buf);
+      background.green = png_get_uint_16(buf + 2);
+      background.blue = png_get_uint_16(buf + 4);
+      background.gray = 0;
+   }
+
+   png_set_bKGD(png_ptr, info_ptr, &background);
+}
+#endif
+
+#ifdef PNG_READ_eXIf_SUPPORTED
+void /* PRIVATE */
+png_handle_eXIf(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   unsigned int i;
+
+   png_debug(1, "in png_handle_eXIf");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   if (length < 2)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "too short");
+      return;
+   }
+
+   else if (info_ptr == NULL || (info_ptr->valid & PNG_INFO_eXIf) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   info_ptr->free_me |= PNG_FREE_EXIF;
+
+   info_ptr->eXIf_buf = png_voidcast(png_bytep,
+             png_malloc_warn(png_ptr, length));
+
+   if (info_ptr->eXIf_buf == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   for (i = 0; i < length; i++)
+   {
+      png_byte buf[1];
+      png_crc_read(png_ptr, buf, 1);
+      info_ptr->eXIf_buf[i] = buf[0];
+      if (i == 1 && buf[0] != 'M' && buf[0] != 'I'
+                 && info_ptr->eXIf_buf[0] != buf[0])
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "incorrect byte-order specifier");
+         png_free(png_ptr, info_ptr->eXIf_buf);
+         info_ptr->eXIf_buf = NULL;
+         return;
+      }
+   }
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   png_set_eXIf_1(png_ptr, info_ptr, length, info_ptr->eXIf_buf);
+
+   png_free(png_ptr, info_ptr->eXIf_buf);
+   info_ptr->eXIf_buf = NULL;
+}
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+void /* PRIVATE */
+png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   unsigned int num, i;
+   png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
+
+   png_debug(1, "in png_handle_hIST");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
+       (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   num = length / 2 ;
+
+   if (num != (unsigned int) png_ptr->num_palette ||
+       num > (unsigned int) PNG_MAX_PALETTE_LENGTH)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   for (i = 0; i < num; i++)
+   {
+      png_byte buf[2];
+
+      png_crc_read(png_ptr, buf, 2);
+      readbuf[i] = png_get_uint_16(buf);
+   }
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   png_set_hIST(png_ptr, info_ptr, readbuf);
+}
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+void /* PRIVATE */
+png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[9];
+   png_uint_32 res_x, res_y;
+   int unit_type;
+
+   png_debug(1, "in png_handle_pHYs");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (length != 9)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 9);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   res_x = png_get_uint_32(buf);
+   res_y = png_get_uint_32(buf + 4);
+   unit_type = buf[8];
+   png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
+}
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+void /* PRIVATE */
+png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[9];
+   png_int_32 offset_x, offset_y;
+   int unit_type;
+
+   png_debug(1, "in png_handle_oFFs");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (length != 9)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 9);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   offset_x = png_get_int_32(buf);
+   offset_y = png_get_int_32(buf + 4);
+   unit_type = buf[8];
+   png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
+}
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+/* Read the pCAL chunk (described in the PNG Extensions document) */
+void /* PRIVATE */
+png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_int_32 X0, X1;
+   png_byte type, nparams;
+   png_bytep buffer, buf, units, endptr;
+   png_charpp params;
+   int i;
+
+   png_debug(1, "in png_handle_pCAL");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
+       length + 1);
+
+   buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
+
+   if (buffer == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   buffer[length] = 0; /* Null terminate the last string */
+
+   png_debug(3, "Finding end of pCAL purpose string");
+   for (buf = buffer; *buf; buf++)
+      /* Empty loop */ ;
+
+   endptr = buffer + length;
+
+   /* We need to have at least 12 bytes after the purpose string
+    * in order to get the parameter information.
+    */
+   if (endptr - buf <= 12)
+   {
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
+   X0 = png_get_int_32((png_bytep)buf+1);
+   X1 = png_get_int_32((png_bytep)buf+5);
+   type = buf[9];
+   nparams = buf[10];
+   units = buf + 11;
+
+   png_debug(3, "Checking pCAL equation type and number of parameters");
+   /* Check that we have the right number of parameters for known
+    * equation types.
+    */
+   if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
+       (type == PNG_EQUATION_BASE_E && nparams != 3) ||
+       (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
+       (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
+   {
+      png_chunk_benign_error(png_ptr, "invalid parameter count");
+      return;
+   }
+
+   else if (type >= PNG_EQUATION_LAST)
+   {
+      png_chunk_benign_error(png_ptr, "unrecognized equation type");
+   }
+
+   for (buf = units; *buf; buf++)
+      /* Empty loop to move past the units string. */ ;
+
+   png_debug(3, "Allocating pCAL parameters array");
+
+   params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
+       nparams * (sizeof (png_charp))));
+
+   if (params == NULL)
+   {
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   /* Get pointers to the start of each parameter string. */
+   for (i = 0; i < nparams; i++)
+   {
+      buf++; /* Skip the null string terminator from previous parameter. */
+
+      png_debug1(3, "Reading pCAL parameter %d", i);
+
+      for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
+         /* Empty loop to move past each parameter string */ ;
+
+      /* Make sure we haven't run out of data yet */
+      if (buf > endptr)
+      {
+         png_free(png_ptr, params);
+         png_chunk_benign_error(png_ptr, "invalid data");
+         return;
+      }
+   }
+
+   png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
+       (png_charp)units, params);
+
+   png_free(png_ptr, params);
+}
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+/* Read the sCAL chunk */
+void /* PRIVATE */
+png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_bytep buffer;
+   size_t i;
+   int state;
+
+   png_debug(1, "in png_handle_sCAL");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   /* Need unit type, width, \0, height: minimum 4 bytes */
+   else if (length < 4)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
+       length + 1);
+
+   buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
+
+   if (buffer == NULL)
+   {
+      png_chunk_benign_error(png_ptr, "out of memory");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+   buffer[length] = 0; /* Null terminate the last string */
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* Validate the unit. */
+   if (buffer[0] != 1 && buffer[0] != 2)
+   {
+      png_chunk_benign_error(png_ptr, "invalid unit");
+      return;
+   }
+
+   /* Validate the ASCII numbers, need two ASCII numbers separated by
+    * a '\0' and they need to fit exactly in the chunk data.
+    */
+   i = 1;
+   state = 0;
+
+   if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
+       i >= length || buffer[i++] != 0)
+      png_chunk_benign_error(png_ptr, "bad width format");
+
+   else if (PNG_FP_IS_POSITIVE(state) == 0)
+      png_chunk_benign_error(png_ptr, "non-positive width");
+
+   else
+   {
+      size_t heighti = i;
+
+      state = 0;
+      if (png_check_fp_number((png_const_charp)buffer, length,
+          &state, &i) == 0 || i != length)
+         png_chunk_benign_error(png_ptr, "bad height format");
+
+      else if (PNG_FP_IS_POSITIVE(state) == 0)
+         png_chunk_benign_error(png_ptr, "non-positive height");
+
+      else
+         /* This is the (only) success case. */
+         png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
+             (png_charp)buffer+1, (png_charp)buffer+heighti);
+   }
+}
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+void /* PRIVATE */
+png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[7];
+   png_time mod_time;
+
+   png_debug(1, "in png_handle_tIME");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+   if (length != 7)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 7);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   mod_time.second = buf[6];
+   mod_time.minute = buf[5];
+   mod_time.hour = buf[4];
+   mod_time.day = buf[3];
+   mod_time.month = buf[2];
+   mod_time.year = png_get_uint_16(buf);
+
+   png_set_tIME(png_ptr, info_ptr, &mod_time);
+}
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_text  text_info;
+   png_bytep buffer;
+   png_charp key;
+   png_charp text;
+   png_uint_32 skip = 0;
+
+   png_debug(1, "in png_handle_tEXt");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "no space in chunk cache");
+         return;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (length > 65535U)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "too large to fit in memory");
+      return;
+   }
+#endif
+
+   buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
+
+   if (buffer == NULL)
+   {
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, skip) != 0)
+      return;
+
+   key = (png_charp)buffer;
+   key[length] = 0;
+
+   for (text = key; *text; text++)
+      /* Empty loop to find end of key */ ;
+
+   if (text != key + length)
+      text++;
+
+   text_info.compression = PNG_TEXT_COMPRESSION_NONE;
+   text_info.key = key;
+   text_info.lang = NULL;
+   text_info.lang_key = NULL;
+   text_info.itxt_length = 0;
+   text_info.text = text;
+   text_info.text_length = strlen(text);
+
+   if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
+      png_warning(png_ptr, "Insufficient memory to process text chunk");
+}
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+/* Note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_const_charp errmsg = NULL;
+   png_bytep       buffer;
+   png_uint_32     keyword_length;
+
+   png_debug(1, "in png_handle_zTXt");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "no space in chunk cache");
+         return;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+   /* Note, "length" is sufficient here; we won't be adding
+    * a null terminator later.
+    */
+   buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
+
+   if (buffer == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* TODO: also check that the keyword contents match the spec! */
+   for (keyword_length = 0;
+      keyword_length < length && buffer[keyword_length] != 0;
+      ++keyword_length)
+      /* Empty loop to find end of name */ ;
+
+   if (keyword_length > 79 || keyword_length < 1)
+      errmsg = "bad keyword";
+
+   /* zTXt must have some LZ data after the keyword, although it may expand to
+    * zero bytes; we need a '\0' at the end of the keyword, the compression type
+    * then the LZ data:
+    */
+   else if (keyword_length + 3 > length)
+      errmsg = "truncated";
+
+   else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
+      errmsg = "unknown compression type";
+
+   else
+   {
+      png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
+
+      /* TODO: at present png_decompress_chunk imposes a single application
+       * level memory limit, this should be split to different values for iCCP
+       * and text chunks.
+       */
+      if (png_decompress_chunk(png_ptr, length, keyword_length+2,
+          &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
+      {
+         png_text text;
+
+         if (png_ptr->read_buffer == NULL)
+           errmsg="Read failure in png_handle_zTXt";
+         else
+         {
+            /* It worked; png_ptr->read_buffer now looks like a tEXt chunk
+             * except for the extra compression type byte and the fact that
+             * it isn't necessarily '\0' terminated.
+             */
+            buffer = png_ptr->read_buffer;
+            buffer[uncompressed_length+(keyword_length+2)] = 0;
+
+            text.compression = PNG_TEXT_COMPRESSION_zTXt;
+            text.key = (png_charp)buffer;
+            text.text = (png_charp)(buffer + keyword_length+2);
+            text.text_length = uncompressed_length;
+            text.itxt_length = 0;
+            text.lang = NULL;
+            text.lang_key = NULL;
+
+            if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
+               errmsg = "insufficient memory";
+         }
+      }
+
+      else
+         errmsg = png_ptr->zstream.msg;
+   }
+
+   if (errmsg != NULL)
+      png_chunk_benign_error(png_ptr, errmsg);
+}
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+/* Note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_const_charp errmsg = NULL;
+   png_bytep buffer;
+   png_uint_32 prefix_length;
+
+   png_debug(1, "in png_handle_iTXt");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "no space in chunk cache");
+         return;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+   buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
+
+   if (buffer == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* First the keyword. */
+   for (prefix_length=0;
+      prefix_length < length && buffer[prefix_length] != 0;
+      ++prefix_length)
+      /* Empty loop */ ;
+
+   /* Perform a basic check on the keyword length here. */
+   if (prefix_length > 79 || prefix_length < 1)
+      errmsg = "bad keyword";
+
+   /* Expect keyword, compression flag, compression type, language, translated
+    * keyword (both may be empty but are 0 terminated) then the text, which may
+    * be empty.
+    */
+   else if (prefix_length + 5 > length)
+      errmsg = "truncated";
+
+   else if (buffer[prefix_length+1] == 0 ||
+      (buffer[prefix_length+1] == 1 &&
+      buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
+   {
+      int compressed = buffer[prefix_length+1] != 0;
+      png_uint_32 language_offset, translated_keyword_offset;
+      png_alloc_size_t uncompressed_length = 0;
+
+      /* Now the language tag */
+      prefix_length += 3;
+      language_offset = prefix_length;
+
+      for (; prefix_length < length && buffer[prefix_length] != 0;
+         ++prefix_length)
+         /* Empty loop */ ;
+
+      /* WARNING: the length may be invalid here, this is checked below. */
+      translated_keyword_offset = ++prefix_length;
+
+      for (; prefix_length < length && buffer[prefix_length] != 0;
+         ++prefix_length)
+         /* Empty loop */ ;
+
+      /* prefix_length should now be at the trailing '\0' of the translated
+       * keyword, but it may already be over the end.  None of this arithmetic
+       * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
+       * systems the available allocation may overflow.
+       */
+      ++prefix_length;
+
+      if (compressed == 0 && prefix_length <= length)
+         uncompressed_length = length - prefix_length;
+
+      else if (compressed != 0 && prefix_length < length)
+      {
+         uncompressed_length = PNG_SIZE_MAX;
+
+         /* TODO: at present png_decompress_chunk imposes a single application
+          * level memory limit, this should be split to different values for
+          * iCCP and text chunks.
+          */
+         if (png_decompress_chunk(png_ptr, length, prefix_length,
+             &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
+            buffer = png_ptr->read_buffer;
+
+         else
+            errmsg = png_ptr->zstream.msg;
+      }
+
+      else
+         errmsg = "truncated";
+
+      if (errmsg == NULL)
+      {
+         png_text text;
+
+         buffer[uncompressed_length+prefix_length] = 0;
+
+         if (compressed == 0)
+            text.compression = PNG_ITXT_COMPRESSION_NONE;
+
+         else
+            text.compression = PNG_ITXT_COMPRESSION_zTXt;
+
+         text.key = (png_charp)buffer;
+         text.lang = (png_charp)buffer + language_offset;
+         text.lang_key = (png_charp)buffer + translated_keyword_offset;
+         text.text = (png_charp)buffer + prefix_length;
+         text.text_length = 0;
+         text.itxt_length = uncompressed_length;
+
+         if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
+            errmsg = "insufficient memory";
+      }
+   }
+
+   else
+      errmsg = "bad compression info";
+
+   if (errmsg != NULL)
+      png_chunk_benign_error(png_ptr, errmsg);
+}
+#endif
+
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+/* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
+static int
+png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
+{
+   png_alloc_size_t limit = PNG_SIZE_MAX;
+
+   if (png_ptr->unknown_chunk.data != NULL)
+   {
+      png_free(png_ptr, png_ptr->unknown_chunk.data);
+      png_ptr->unknown_chunk.data = NULL;
+   }
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_malloc_max > 0 &&
+       png_ptr->user_chunk_malloc_max < limit)
+      limit = png_ptr->user_chunk_malloc_max;
+
+#  elif PNG_USER_CHUNK_MALLOC_MAX > 0
+   if (PNG_USER_CHUNK_MALLOC_MAX < limit)
+      limit = PNG_USER_CHUNK_MALLOC_MAX;
+#  endif
+
+   if (length <= limit)
+   {
+      PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
+      /* The following is safe because of the PNG_SIZE_MAX init above */
+      png_ptr->unknown_chunk.size = (size_t)length/*SAFE*/;
+      /* 'mode' is a flag array, only the bottom four bits matter here */
+      png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
+
+      if (length == 0)
+         png_ptr->unknown_chunk.data = NULL;
+
+      else
+      {
+         /* Do a 'warn' here - it is handled below. */
+         png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
+             png_malloc_warn(png_ptr, length));
+      }
+   }
+
+   if (png_ptr->unknown_chunk.data == NULL && length > 0)
+   {
+      /* This is benign because we clean up correctly */
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
+      return 0;
+   }
+
+   else
+   {
+      if (length > 0)
+         png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
+      png_crc_finish(png_ptr, 0);
+      return 1;
+   }
+}
+#endif /* READ_UNKNOWN_CHUNKS */
+
+/* Handle an unknown, or known but disabled, chunk */
+void /* PRIVATE */
+png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
+    png_uint_32 length, int keep)
+{
+   int handled = 0; /* the chunk was handled */
+
+   png_debug(1, "in png_handle_unknown");
+
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+   /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
+    * the bug which meant that setting a non-default behavior for a specific
+    * chunk would be ignored (the default was always used unless a user
+    * callback was installed).
+    *
+    * 'keep' is the value from the png_chunk_unknown_handling, the setting for
+    * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
+    * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
+    * This is just an optimization to avoid multiple calls to the lookup
+    * function.
+    */
+#  ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#     ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
+#     endif
+#  endif
+
+   /* One of the following methods will read the chunk or skip it (at least one
+    * of these is always defined because this is the only way to switch on
+    * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+    */
+#  ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   /* The user callback takes precedence over the chunk keep value, but the
+    * keep value is still required to validate a save of a critical chunk.
+    */
+   if (png_ptr->read_user_chunk_fn != NULL)
+   {
+      if (png_cache_unknown_chunk(png_ptr, length) != 0)
+      {
+         /* Callback to user unknown chunk handler */
+         int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
+             &png_ptr->unknown_chunk);
+
+         /* ret is:
+          * negative: An error occurred; png_chunk_error will be called.
+          *     zero: The chunk was not handled, the chunk will be discarded
+          *           unless png_set_keep_unknown_chunks has been used to set
+          *           a 'keep' behavior for this particular chunk, in which
+          *           case that will be used.  A critical chunk will cause an
+          *           error at this point unless it is to be saved.
+          * positive: The chunk was handled, libpng will ignore/discard it.
+          */
+         if (ret < 0)
+            png_chunk_error(png_ptr, "error in user chunk");
+
+         else if (ret == 0)
+         {
+            /* If the keep value is 'default' or 'never' override it, but
+             * still error out on critical chunks unless the keep value is
+             * 'always'  While this is weird it is the behavior in 1.4.12.
+             * A possible improvement would be to obey the value set for the
+             * chunk, but this would be an API change that would probably
+             * damage some applications.
+             *
+             * The png_app_warning below catches the case that matters, where
+             * the application has not set specific save or ignore for this
+             * chunk or global save or ignore.
+             */
+            if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
+            {
+#              ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+               if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
+               {
+                  png_chunk_warning(png_ptr, "Saving unknown chunk:");
+                  png_app_warning(png_ptr,
+                      "forcing save of an unhandled chunk;"
+                      " please call png_set_keep_unknown_chunks");
+                      /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
+               }
+#              endif
+               keep = PNG_HANDLE_CHUNK_IF_SAFE;
+            }
+         }
+
+         else /* chunk was handled */
+         {
+            handled = 1;
+            /* Critical chunks can be safely discarded at this point. */
+            keep = PNG_HANDLE_CHUNK_NEVER;
+         }
+      }
+
+      else
+         keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
+   }
+
+   else
+   /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
+#  endif /* READ_USER_CHUNKS */
+
+#  ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+   {
+      /* keep is currently just the per-chunk setting, if there was no
+       * setting change it to the global default now (not that this may
+       * still be AS_DEFAULT) then obtain the cache of the chunk if required,
+       * if not simply skip the chunk.
+       */
+      if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+         keep = png_ptr->unknown_default;
+
+      if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
+         (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
+          PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
+      {
+         if (png_cache_unknown_chunk(png_ptr, length) == 0)
+            keep = PNG_HANDLE_CHUNK_NEVER;
+      }
+
+      else
+         png_crc_finish(png_ptr, length);
+   }
+#  else
+#     ifndef PNG_READ_USER_CHUNKS_SUPPORTED
+#        error no method to support READ_UNKNOWN_CHUNKS
+#     endif
+
+   {
+      /* If here there is no read callback pointer set and no support is
+       * compiled in to just save the unknown chunks, so simply skip this
+       * chunk.  If 'keep' is something other than AS_DEFAULT or NEVER then
+       * the app has erroneously asked for unknown chunk saving when there
+       * is no support.
+       */
+      if (keep > PNG_HANDLE_CHUNK_NEVER)
+         png_app_error(png_ptr, "no unknown chunk support available");
+
+      png_crc_finish(png_ptr, length);
+   }
+#  endif
+
+#  ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+   /* Now store the chunk in the chunk list if appropriate, and if the limits
+    * permit it.
+    */
+   if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
+      (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
+       PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
+   {
+#     ifdef PNG_USER_LIMITS_SUPPORTED
+      switch (png_ptr->user_chunk_cache_max)
+      {
+         case 2:
+            png_ptr->user_chunk_cache_max = 1;
+            png_chunk_benign_error(png_ptr, "no space in chunk cache");
+            /* FALLTHROUGH */
+         case 1:
+            /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
+             * chunk being skipped, now there will be a hard error below.
+             */
+            break;
+
+         default: /* not at limit */
+            --(png_ptr->user_chunk_cache_max);
+            /* FALLTHROUGH */
+         case 0: /* no limit */
+#  endif /* USER_LIMITS */
+            /* Here when the limit isn't reached or when limits are compiled
+             * out; store the chunk.
+             */
+            png_set_unknown_chunks(png_ptr, info_ptr,
+                &png_ptr->unknown_chunk, 1);
+            handled = 1;
+#  ifdef PNG_USER_LIMITS_SUPPORTED
+            break;
+      }
+#  endif
+   }
+#  else /* no store support: the chunk must be handled by the user callback */
+   PNG_UNUSED(info_ptr)
+#  endif
+
+   /* Regardless of the error handling below the cached data (if any) can be
+    * freed now.  Notice that the data is not freed if there is a png_error, but
+    * it will be freed by destroy_read_struct.
+    */
+   if (png_ptr->unknown_chunk.data != NULL)
+      png_free(png_ptr, png_ptr->unknown_chunk.data);
+   png_ptr->unknown_chunk.data = NULL;
+
+#else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
+   /* There is no support to read an unknown chunk, so just skip it. */
+   png_crc_finish(png_ptr, length);
+   PNG_UNUSED(info_ptr)
+   PNG_UNUSED(keep)
+#endif /* !READ_UNKNOWN_CHUNKS */
+
+   /* Check for unhandled critical chunks */
+   if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
+      png_chunk_error(png_ptr, "unhandled critical chunk");
+}
+
+/* This function is called to verify that a chunk name is valid.
+ * This function can't have the "critical chunk check" incorporated
+ * into it, since in the future we will need to be able to call user
+ * functions to handle unknown critical chunks after we check that
+ * the chunk name itself is valid.
+ */
+
+/* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
+ *
+ * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+ */
+
+void /* PRIVATE */
+png_check_chunk_name(png_const_structrp png_ptr, png_uint_32 chunk_name)
+{
+   int i;
+   png_uint_32 cn=chunk_name;
+
+   png_debug(1, "in png_check_chunk_name");
+
+   for (i=1; i<=4; ++i)
+   {
+      int c = cn & 0xff;
+
+      if (c < 65 || c > 122 || (c > 90 && c < 97))
+         png_chunk_error(png_ptr, "invalid chunk type");
+
+      cn >>= 8;
+   }
+}
+
+void /* PRIVATE */
+png_check_chunk_length(png_const_structrp png_ptr, png_uint_32 length)
+{
+   png_alloc_size_t limit = PNG_UINT_31_MAX;
+
+# ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_malloc_max > 0 &&
+       png_ptr->user_chunk_malloc_max < limit)
+      limit = png_ptr->user_chunk_malloc_max;
+# elif PNG_USER_CHUNK_MALLOC_MAX > 0
+   if (PNG_USER_CHUNK_MALLOC_MAX < limit)
+      limit = PNG_USER_CHUNK_MALLOC_MAX;
+# endif
+   if (png_ptr->chunk_name == png_IDAT)
+   {
+      png_alloc_size_t idat_limit = PNG_UINT_31_MAX;
+      size_t row_factor =
+         (size_t)png_ptr->width
+         * (size_t)png_ptr->channels
+         * (png_ptr->bit_depth > 8? 2: 1)
+         + 1
+         + (png_ptr->interlaced? 6: 0);
+      if (png_ptr->height > PNG_UINT_32_MAX/row_factor)
+         idat_limit = PNG_UINT_31_MAX;
+      else
+         idat_limit = png_ptr->height * row_factor;
+      row_factor = row_factor > 32566? 32566 : row_factor;
+      idat_limit += 6 + 5*(idat_limit/row_factor+1); /* zlib+deflate overhead */
+      idat_limit=idat_limit < PNG_UINT_31_MAX? idat_limit : PNG_UINT_31_MAX;
+      limit = limit < idat_limit? idat_limit : limit;
+   }
+
+   if (length > limit)
+   {
+      png_debug2(0," length = %lu, limit = %lu",
+         (unsigned long)length,(unsigned long)limit);
+      png_chunk_error(png_ptr, "chunk data is too large");
+   }
+}
+
+/* Combines the row recently read in with the existing pixels in the row.  This
+ * routine takes care of alpha and transparency if requested.  This routine also
+ * handles the two methods of progressive display of interlaced images,
+ * depending on the 'display' value; if 'display' is true then the whole row
+ * (dp) is filled from the start by replicating the available pixels.  If
+ * 'display' is false only those pixels present in the pass are filled in.
+ */
+void /* PRIVATE */
+png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
+{
+   unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
+   png_const_bytep sp = png_ptr->row_buf + 1;
+   png_alloc_size_t row_width = png_ptr->width;
+   unsigned int pass = png_ptr->pass;
+   png_bytep end_ptr = 0;
+   png_byte end_byte = 0;
+   unsigned int end_mask;
+
+   png_debug(1, "in png_combine_row");
+
+   /* Added in 1.5.6: it should not be possible to enter this routine until at
+    * least one row has been read from the PNG data and transformed.
+    */
+   if (pixel_depth == 0)
+      png_error(png_ptr, "internal row logic error");
+
+   /* Added in 1.5.4: the pixel depth should match the information returned by
+    * any call to png_read_update_info at this point.  Do not continue if we got
+    * this wrong.
+    */
+   if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
+          PNG_ROWBYTES(pixel_depth, row_width))
+      png_error(png_ptr, "internal row size calculation error");
+
+   /* Don't expect this to ever happen: */
+   if (row_width == 0)
+      png_error(png_ptr, "internal row width error");
+
+   /* Preserve the last byte in cases where only part of it will be overwritten,
+    * the multiply below may overflow, we don't care because ANSI-C guarantees
+    * we get the low bits.
+    */
+   end_mask = (pixel_depth * row_width) & 7;
+   if (end_mask != 0)
+   {
+      /* end_ptr == NULL is a flag to say do nothing */
+      end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
+      end_byte = *end_ptr;
+#     ifdef PNG_READ_PACKSWAP_SUPPORTED
+      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+         /* little-endian byte */
+         end_mask = (unsigned int)(0xff << end_mask);
+
+      else /* big-endian byte */
+#     endif
+      end_mask = 0xff >> end_mask;
+      /* end_mask is now the bits to *keep* from the destination row */
+   }
+
+   /* For non-interlaced images this reduces to a memcpy(). A memcpy()
+    * will also happen if interlacing isn't supported or if the application
+    * does not call png_set_interlace_handling().  In the latter cases the
+    * caller just gets a sequence of the unexpanded rows from each interlace
+    * pass.
+    */
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0 &&
+       pass < 6 && (display == 0 ||
+       /* The following copies everything for 'display' on passes 0, 2 and 4. */
+       (display == 1 && (pass & 1) != 0)))
+   {
+      /* Narrow images may have no bits in a pass; the caller should handle
+       * this, but this test is cheap:
+       */
+      if (row_width <= PNG_PASS_START_COL(pass))
+         return;
+
+      if (pixel_depth < 8)
+      {
+         /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
+          * into 32 bits, then a single loop over the bytes using the four byte
+          * values in the 32-bit mask can be used.  For the 'display' option the
+          * expanded mask may also not require any masking within a byte.  To
+          * make this work the PACKSWAP option must be taken into account - it
+          * simply requires the pixels to be reversed in each byte.
+          *
+          * The 'regular' case requires a mask for each of the first 6 passes,
+          * the 'display' case does a copy for the even passes in the range
+          * 0..6.  This has already been handled in the test above.
+          *
+          * The masks are arranged as four bytes with the first byte to use in
+          * the lowest bits (little-endian) regardless of the order (PACKSWAP or
+          * not) of the pixels in each byte.
+          *
+          * NOTE: the whole of this logic depends on the caller of this function
+          * only calling it on rows appropriate to the pass.  This function only
+          * understands the 'x' logic; the 'y' logic is handled by the caller.
+          *
+          * The following defines allow generation of compile time constant bit
+          * masks for each pixel depth and each possibility of swapped or not
+          * swapped bytes.  Pass 'p' is in the range 0..6; 'x', a pixel index,
+          * is in the range 0..7; and the result is 1 if the pixel is to be
+          * copied in the pass, 0 if not.  'S' is for the sparkle method, 'B'
+          * for the block method.
+          *
+          * With some compilers a compile time expression of the general form:
+          *
+          *    (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
+          *
+          * Produces warnings with values of 'shift' in the range 33 to 63
+          * because the right hand side of the ?: expression is evaluated by
+          * the compiler even though it isn't used.  Microsoft Visual C (various
+          * versions) and the Intel C compiler are known to do this.  To avoid
+          * this the following macros are used in 1.5.6.  This is a temporary
+          * solution to avoid destabilizing the code during the release process.
+          */
+#        if PNG_USE_COMPILE_TIME_MASKS
+#           define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
+#           define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
+#        else
+#           define PNG_LSR(x,s) ((x)>>(s))
+#           define PNG_LSL(x,s) ((x)<<(s))
+#        endif
+#        define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
+           PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
+#        define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
+           PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
+
+         /* Return a mask for pass 'p' pixel 'x' at depth 'd'.  The mask is
+          * little endian - the first pixel is at bit 0 - however the extra
+          * parameter 's' can be set to cause the mask position to be swapped
+          * within each byte, to match the PNG format.  This is done by XOR of
+          * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
+          */
+#        define PIXEL_MASK(p,x,d,s) \
+            (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
+
+         /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
+          */
+#        define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
+#        define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
+
+         /* Combine 8 of these to get the full mask.  For the 1-bpp and 2-bpp
+          * cases the result needs replicating, for the 4-bpp case the above
+          * generates a full 32 bits.
+          */
+#        define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
+
+#        define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
+            S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
+            S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
+
+#        define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
+            B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
+            B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
+
+#if PNG_USE_COMPILE_TIME_MASKS
+         /* Utility macros to construct all the masks for a depth/swap
+          * combination.  The 's' parameter says whether the format is PNG
+          * (big endian bytes) or not.  Only the three odd-numbered passes are
+          * required for the display/block algorithm.
+          */
+#        define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
+            S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
+
+#        define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
+
+#        define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
+
+         /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
+          * then pass:
+          */
+         static const png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
+         {
+            /* Little-endian byte masks for PACKSWAP */
+            { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
+            /* Normal (big-endian byte) masks - PNG format */
+            { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
+         };
+
+         /* display_mask has only three entries for the odd passes, so index by
+          * pass>>1.
+          */
+         static const png_uint_32 display_mask[2][3][3] =
+         {
+            /* Little-endian byte masks for PACKSWAP */
+            { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
+            /* Normal (big-endian byte) masks - PNG format */
+            { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
+         };
+
+#        define MASK(pass,depth,display,png)\
+            ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
+               row_mask[png][DEPTH_INDEX(depth)][pass])
+
+#else /* !PNG_USE_COMPILE_TIME_MASKS */
+         /* This is the runtime alternative: it seems unlikely that this will
+          * ever be either smaller or faster than the compile time approach.
+          */
+#        define MASK(pass,depth,display,png)\
+            ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
+#endif /* !USE_COMPILE_TIME_MASKS */
+
+         /* Use the appropriate mask to copy the required bits.  In some cases
+          * the byte mask will be 0 or 0xff; optimize these cases.  row_width is
+          * the number of pixels, but the code copies bytes, so it is necessary
+          * to special case the end.
+          */
+         png_uint_32 pixels_per_byte = 8 / pixel_depth;
+         png_uint_32 mask;
+
+#        ifdef PNG_READ_PACKSWAP_SUPPORTED
+         if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+            mask = MASK(pass, pixel_depth, display, 0);
+
+         else
+#        endif
+         mask = MASK(pass, pixel_depth, display, 1);
+
+         for (;;)
+         {
+            png_uint_32 m;
+
+            /* It doesn't matter in the following if png_uint_32 has more than
+             * 32 bits because the high bits always match those in m<<24; it is,
+             * however, essential to use OR here, not +, because of this.
+             */
+            m = mask;
+            mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
+            m &= 0xff;
+
+            if (m != 0) /* something to copy */
+            {
+               if (m != 0xff)
+                  *dp = (png_byte)((*dp & ~m) | (*sp & m));
+               else
+                  *dp = *sp;
+            }
+
+            /* NOTE: this may overwrite the last byte with garbage if the image
+             * is not an exact number of bytes wide; libpng has always done
+             * this.
+             */
+            if (row_width <= pixels_per_byte)
+               break; /* May need to restore part of the last byte */
+
+            row_width -= pixels_per_byte;
+            ++dp;
+            ++sp;
+         }
+      }
+
+      else /* pixel_depth >= 8 */
+      {
+         unsigned int bytes_to_copy, bytes_to_jump;
+
+         /* Validate the depth - it must be a multiple of 8 */
+         if (pixel_depth & 7)
+            png_error(png_ptr, "invalid user transform pixel depth");
+
+         pixel_depth >>= 3; /* now in bytes */
+         row_width *= pixel_depth;
+
+         /* Regardless of pass number the Adam 7 interlace always results in a
+          * fixed number of pixels to copy then to skip.  There may be a
+          * different number of pixels to skip at the start though.
+          */
+         {
+            unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
+
+            row_width -= offset;
+            dp += offset;
+            sp += offset;
+         }
+
+         /* Work out the bytes to copy. */
+         if (display != 0)
+         {
+            /* When doing the 'block' algorithm the pixel in the pass gets
+             * replicated to adjacent pixels.  This is why the even (0,2,4,6)
+             * passes are skipped above - the entire expanded row is copied.
+             */
+            bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
+
+            /* But don't allow this number to exceed the actual row width. */
+            if (bytes_to_copy > row_width)
+               bytes_to_copy = (unsigned int)/*SAFE*/row_width;
+         }
+
+         else /* normal row; Adam7 only ever gives us one pixel to copy. */
+            bytes_to_copy = pixel_depth;
+
+         /* In Adam7 there is a constant offset between where the pixels go. */
+         bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
+
+         /* And simply copy these bytes.  Some optimization is possible here,
+          * depending on the value of 'bytes_to_copy'.  Special case the low
+          * byte counts, which we know to be frequent.
+          *
+          * Notice that these cases all 'return' rather than 'break' - this
+          * avoids an unnecessary test on whether to restore the last byte
+          * below.
+          */
+         switch (bytes_to_copy)
+         {
+            case 1:
+               for (;;)
+               {
+                  *dp = *sp;
+
+                  if (row_width <= bytes_to_jump)
+                     return;
+
+                  dp += bytes_to_jump;
+                  sp += bytes_to_jump;
+                  row_width -= bytes_to_jump;
+               }
+
+            case 2:
+               /* There is a possibility of a partial copy at the end here; this
+                * slows the code down somewhat.
+                */
+               do
+               {
+                  dp[0] = sp[0]; dp[1] = sp[1];
+
+                  if (row_width <= bytes_to_jump)
+                     return;
+
+                  sp += bytes_to_jump;
+                  dp += bytes_to_jump;
+                  row_width -= bytes_to_jump;
+               }
+               while (row_width > 1);
+
+               /* And there can only be one byte left at this point: */
+               *dp = *sp;
+               return;
+
+            case 3:
+               /* This can only be the RGB case, so each copy is exactly one
+                * pixel and it is not necessary to check for a partial copy.
+                */
+               for (;;)
+               {
+                  dp[0] = sp[0]; dp[1] = sp[1]; dp[2] = sp[2];
+
+                  if (row_width <= bytes_to_jump)
+                     return;
+
+                  sp += bytes_to_jump;
+                  dp += bytes_to_jump;
+                  row_width -= bytes_to_jump;
+               }
+
+            default:
+#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
+               /* Check for double byte alignment and, if possible, use a
+                * 16-bit copy.  Don't attempt this for narrow images - ones that
+                * are less than an interlace panel wide.  Don't attempt it for
+                * wide bytes_to_copy either - use the memcpy there.
+                */
+               if (bytes_to_copy < 16 /*else use memcpy*/ &&
+                   png_isaligned(dp, png_uint_16) &&
+                   png_isaligned(sp, png_uint_16) &&
+                   bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
+                   bytes_to_jump % (sizeof (png_uint_16)) == 0)
+               {
+                  /* Everything is aligned for png_uint_16 copies, but try for
+                   * png_uint_32 first.
+                   */
+                  if (png_isaligned(dp, png_uint_32) &&
+                      png_isaligned(sp, png_uint_32) &&
+                      bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
+                      bytes_to_jump % (sizeof (png_uint_32)) == 0)
+                  {
+                     png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
+                     png_const_uint_32p sp32 = png_aligncastconst(
+                         png_const_uint_32p, sp);
+                     size_t skip = (bytes_to_jump-bytes_to_copy) /
+                         (sizeof (png_uint_32));
+
+                     do
+                     {
+                        size_t c = bytes_to_copy;
+                        do
+                        {
+                           *dp32++ = *sp32++;
+                           c -= (sizeof (png_uint_32));
+                        }
+                        while (c > 0);
+
+                        if (row_width <= bytes_to_jump)
+                           return;
+
+                        dp32 += skip;
+                        sp32 += skip;
+                        row_width -= bytes_to_jump;
+                     }
+                     while (bytes_to_copy <= row_width);
+
+                     /* Get to here when the row_width truncates the final copy.
+                      * There will be 1-3 bytes left to copy, so don't try the
+                      * 16-bit loop below.
+                      */
+                     dp = (png_bytep)dp32;
+                     sp = (png_const_bytep)sp32;
+                     do
+                        *dp++ = *sp++;
+                     while (--row_width > 0);
+                     return;
+                  }
+
+                  /* Else do it in 16-bit quantities, but only if the size is
+                   * not too large.
+                   */
+                  else
+                  {
+                     png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
+                     png_const_uint_16p sp16 = png_aligncastconst(
+                        png_const_uint_16p, sp);
+                     size_t skip = (bytes_to_jump-bytes_to_copy) /
+                        (sizeof (png_uint_16));
+
+                     do
+                     {
+                        size_t c = bytes_to_copy;
+                        do
+                        {
+                           *dp16++ = *sp16++;
+                           c -= (sizeof (png_uint_16));
+                        }
+                        while (c > 0);
+
+                        if (row_width <= bytes_to_jump)
+                           return;
+
+                        dp16 += skip;
+                        sp16 += skip;
+                        row_width -= bytes_to_jump;
+                     }
+                     while (bytes_to_copy <= row_width);
+
+                     /* End of row - 1 byte left, bytes_to_copy > row_width: */
+                     dp = (png_bytep)dp16;
+                     sp = (png_const_bytep)sp16;
+                     do
+                        *dp++ = *sp++;
+                     while (--row_width > 0);
+                     return;
+                  }
+               }
+#endif /* ALIGN_TYPE code */
+
+               /* The true default - use a memcpy: */
+               for (;;)
+               {
+                  memcpy(dp, sp, bytes_to_copy);
+
+                  if (row_width <= bytes_to_jump)
+                     return;
+
+                  sp += bytes_to_jump;
+                  dp += bytes_to_jump;
+                  row_width -= bytes_to_jump;
+                  if (bytes_to_copy > row_width)
+                     bytes_to_copy = (unsigned int)/*SAFE*/row_width;
+               }
+         }
+
+         /* NOT REACHED*/
+      } /* pixel_depth >= 8 */
+
+      /* Here if pixel_depth < 8 to check 'end_ptr' below. */
+   }
+   else
+#endif /* READ_INTERLACING */
+
+   /* If here then the switch above wasn't used so just memcpy the whole row
+    * from the temporary row buffer (notice that this overwrites the end of the
+    * destination row if it is a partial byte.)
+    */
+   memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
+
+   /* Restore the overwritten bits from the last byte if necessary. */
+   if (end_ptr != NULL)
+      *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
+}
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+void /* PRIVATE */
+png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
+    png_uint_32 transformations /* Because these may affect the byte layout */)
+{
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Offset to next interlace block */
+   static const unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   png_debug(1, "in png_do_read_interlace");
+   if (row != NULL && row_info != NULL)
+   {
+      png_uint_32 final_width;
+
+      final_width = row_info->width * png_pass_inc[pass];
+
+      switch (row_info->pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp = row + (size_t)((row_info->width - 1) >> 3);
+            png_bytep dp = row + (size_t)((final_width - 1) >> 3);
+            unsigned int sshift, dshift;
+            unsigned int s_start, s_end;
+            int s_inc;
+            int jstop = (int)png_pass_inc[pass];
+            png_byte v;
+            png_uint_32 i;
+            int j;
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+            if ((transformations & PNG_PACKSWAP) != 0)
+            {
+                sshift = ((row_info->width + 7) & 0x07);
+                dshift = ((final_width + 7) & 0x07);
+                s_start = 7;
+                s_end = 0;
+                s_inc = -1;
+            }
+
+            else
+#endif
+            {
+                sshift = 7 - ((row_info->width + 7) & 0x07);
+                dshift = 7 - ((final_width + 7) & 0x07);
+                s_start = 0;
+                s_end = 7;
+                s_inc = 1;
+            }
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               v = (png_byte)((*sp >> sshift) & 0x01);
+               for (j = 0; j < jstop; j++)
+               {
+                  unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
+                  tmp |= (unsigned int)(v << dshift);
+                  *dp = (png_byte)(tmp & 0xff);
+
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+
+                  else
+                     dshift = (unsigned int)((int)dshift + s_inc);
+               }
+
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+
+               else
+                  sshift = (unsigned int)((int)sshift + s_inc);
+            }
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
+            png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
+            unsigned int sshift, dshift;
+            unsigned int s_start, s_end;
+            int s_inc;
+            int jstop = (int)png_pass_inc[pass];
+            png_uint_32 i;
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+            if ((transformations & PNG_PACKSWAP) != 0)
+            {
+               sshift = (((row_info->width + 3) & 0x03) << 1);
+               dshift = (((final_width + 3) & 0x03) << 1);
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+
+            else
+#endif
+            {
+               sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1);
+               dshift = ((3 - ((final_width + 3) & 0x03)) << 1);
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               png_byte v;
+               int j;
+
+               v = (png_byte)((*sp >> sshift) & 0x03);
+               for (j = 0; j < jstop; j++)
+               {
+                  unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
+                  tmp |= (unsigned int)(v << dshift);
+                  *dp = (png_byte)(tmp & 0xff);
+
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+
+                  else
+                     dshift = (unsigned int)((int)dshift + s_inc);
+               }
+
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+
+               else
+                  sshift = (unsigned int)((int)sshift + s_inc);
+            }
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp = row + (size_t)((row_info->width - 1) >> 1);
+            png_bytep dp = row + (size_t)((final_width - 1) >> 1);
+            unsigned int sshift, dshift;
+            unsigned int s_start, s_end;
+            int s_inc;
+            png_uint_32 i;
+            int jstop = (int)png_pass_inc[pass];
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+            if ((transformations & PNG_PACKSWAP) != 0)
+            {
+               sshift = (((row_info->width + 1) & 0x01) << 2);
+               dshift = (((final_width + 1) & 0x01) << 2);
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+
+            else
+#endif
+            {
+               sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2);
+               dshift = ((1 - ((final_width + 1) & 0x01)) << 2);
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
+               int j;
+
+               for (j = 0; j < jstop; j++)
+               {
+                  unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
+                  tmp |= (unsigned int)(v << dshift);
+                  *dp = (png_byte)(tmp & 0xff);
+
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+
+                  else
+                     dshift = (unsigned int)((int)dshift + s_inc);
+               }
+
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+
+               else
+                  sshift = (unsigned int)((int)sshift + s_inc);
+            }
+            break;
+         }
+
+         default:
+         {
+            size_t pixel_bytes = (row_info->pixel_depth >> 3);
+
+            png_bytep sp = row + (size_t)(row_info->width - 1)
+                * pixel_bytes;
+
+            png_bytep dp = row + (size_t)(final_width - 1) * pixel_bytes;
+
+            int jstop = (int)png_pass_inc[pass];
+            png_uint_32 i;
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
+               int j;
+
+               memcpy(v, sp, pixel_bytes);
+
+               for (j = 0; j < jstop; j++)
+               {
+                  memcpy(dp, v, pixel_bytes);
+                  dp -= pixel_bytes;
+               }
+
+               sp -= pixel_bytes;
+            }
+            break;
+         }
+      }
+
+      row_info->width = final_width;
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
+   }
+#ifndef PNG_READ_PACKSWAP_SUPPORTED
+   PNG_UNUSED(transformations)  /* Silence compiler warning */
+#endif
+}
+#endif /* READ_INTERLACING */
+
+static void
+png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t i;
+   size_t istop = row_info->rowbytes;
+   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+   png_bytep rp = row + bpp;
+
+   PNG_UNUSED(prev_row)
+
+   for (i = bpp; i < istop; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+      rp++;
+   }
+}
+
+static void
+png_read_filter_row_up(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t i;
+   size_t istop = row_info->rowbytes;
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+
+   for (i = 0; i < istop; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+      rp++;
+   }
+}
+
+static void
+png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t i;
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+   size_t istop = row_info->rowbytes - bpp;
+
+   for (i = 0; i < bpp; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) +
+         ((int)(*pp++) / 2 )) & 0xff);
+
+      rp++;
+   }
+
+   for (i = 0; i < istop; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) +
+         (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+      rp++;
+   }
+}
+
+static void
+png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   png_bytep rp_end = row + row_info->rowbytes;
+   int a, c;
+
+   /* First pixel/byte */
+   c = *prev_row++;
+   a = *row + c;
+   *row++ = (png_byte)a;
+
+   /* Remainder */
+   while (row < rp_end)
+   {
+      int b, pa, pb, pc, p;
+
+      a &= 0xff; /* From previous iteration or start */
+      b = *prev_row++;
+
+      p = b - c;
+      pc = a - c;
+
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+      /* Find the best predictor, the least of pa, pb, pc favoring the earlier
+       * ones in the case of a tie.
+       */
+      if (pb < pa)
+      {
+         pa = pb; a = b;
+      }
+      if (pc < pa) a = c;
+
+      /* Calculate the current pixel in a, and move the previous row pixel to c
+       * for the next time round the loop
+       */
+      c = b;
+      a += *row;
+      *row++ = (png_byte)a;
+   }
+}
+
+static void
+png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+   png_bytep rp_end = row + bpp;
+
+   /* Process the first pixel in the row completely (this is the same as 'up'
+    * because there is only one candidate predictor for the first row).
+    */
+   while (row < rp_end)
+   {
+      int a = *row + *prev_row++;
+      *row++ = (png_byte)a;
+   }
+
+   /* Remainder */
+   rp_end = rp_end + (row_info->rowbytes - bpp);
+
+   while (row < rp_end)
+   {
+      int a, b, c, pa, pb, pc, p;
+
+      c = *(prev_row - bpp);
+      a = *(row - bpp);
+      b = *prev_row++;
+
+      p = b - c;
+      pc = a - c;
+
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+      if (pb < pa)
+      {
+         pa = pb; a = b;
+      }
+      if (pc < pa) a = c;
+
+      a += *row;
+      *row++ = (png_byte)a;
+   }
+}
+
+static void
+png_init_filter_functions(png_structrp pp)
+   /* This function is called once for every PNG image (except for PNG images
+    * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
+    * implementations required to reverse the filtering of PNG rows.  Reversing
+    * the filter is the first transformation performed on the row data.  It is
+    * performed in place, therefore an implementation can be selected based on
+    * the image pixel format.  If the implementation depends on image width then
+    * take care to ensure that it works correctly if the image is interlaced -
+    * interlacing causes the actual row width to vary.
+    */
+{
+   unsigned int bpp = (pp->pixel_depth + 7) >> 3;
+
+   pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
+   pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
+   if (bpp == 1)
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth_1byte_pixel;
+   else
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth_multibyte_pixel;
+
+#ifdef PNG_FILTER_OPTIMIZATIONS
+   /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
+    * call to install hardware optimizations for the above functions; simply
+    * replace whatever elements of the pp->read_filter[] array with a hardware
+    * specific (or, for that matter, generic) optimization.
+    *
+    * To see an example of this examine what configure.ac does when
+    * --enable-arm-neon is specified on the command line.
+    */
+   PNG_FILTER_OPTIMIZATIONS(pp, bpp);
+#endif
+}
+
+void /* PRIVATE */
+png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row, int filter)
+{
+   /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
+    * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
+    * implementations.  See png_init_filter_functions above.
+    */
+   if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
+   {
+      if (pp->read_filter[0] == NULL)
+         png_init_filter_functions(pp);
+
+      pp->read_filter[filter-1](row_info, row, prev_row);
+   }
+}
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+void /* PRIVATE */
+png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
+    png_alloc_size_t avail_out)
+{
+   /* Loop reading IDATs and decompressing the result into output[avail_out] */
+   png_ptr->zstream.next_out = output;
+   png_ptr->zstream.avail_out = 0; /* safety: set below */
+
+   if (output == NULL)
+      avail_out = 0;
+
+   do
+   {
+      int ret;
+      png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
+
+      if (png_ptr->zstream.avail_in == 0)
+      {
+         uInt avail_in;
+         png_bytep buffer;
+
+         while (png_ptr->idat_size == 0)
+         {
+            png_crc_finish(png_ptr, 0);
+
+            png_ptr->idat_size = png_read_chunk_header(png_ptr);
+            /* This is an error even in the 'check' case because the code just
+             * consumed a non-IDAT header.
+             */
+            if (png_ptr->chunk_name != png_IDAT)
+               png_error(png_ptr, "Not enough image data");
+         }
+
+         avail_in = png_ptr->IDAT_read_size;
+
+         if (avail_in > png_ptr->idat_size)
+            avail_in = (uInt)png_ptr->idat_size;
+
+         /* A PNG with a gradually increasing IDAT size will defeat this attempt
+          * to minimize memory usage by causing lots of re-allocs, but
+          * realistically doing IDAT_read_size re-allocs is not likely to be a
+          * big problem.
+          */
+         buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
+
+         png_crc_read(png_ptr, buffer, avail_in);
+         png_ptr->idat_size -= avail_in;
+
+         png_ptr->zstream.next_in = buffer;
+         png_ptr->zstream.avail_in = avail_in;
+      }
+
+      /* And set up the output side. */
+      if (output != NULL) /* standard read */
+      {
+         uInt out = ZLIB_IO_MAX;
+
+         if (out > avail_out)
+            out = (uInt)avail_out;
+
+         avail_out -= out;
+         png_ptr->zstream.avail_out = out;
+      }
+
+      else /* after last row, checking for end */
+      {
+         png_ptr->zstream.next_out = tmpbuf;
+         png_ptr->zstream.avail_out = (sizeof tmpbuf);
+      }
+
+      /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
+       * process.  If the LZ stream is truncated the sequential reader will
+       * terminally damage the stream, above, by reading the chunk header of the
+       * following chunk (it then exits with png_error).
+       *
+       * TODO: deal more elegantly with truncated IDAT lists.
+       */
+      ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH);
+
+      /* Take the unconsumed output back. */
+      if (output != NULL)
+         avail_out += png_ptr->zstream.avail_out;
+
+      else /* avail_out counts the extra bytes */
+         avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
+
+      png_ptr->zstream.avail_out = 0;
+
+      if (ret == Z_STREAM_END)
+      {
+         /* Do this for safety; we won't read any more into this row. */
+         png_ptr->zstream.next_out = NULL;
+
+         png_ptr->mode |= PNG_AFTER_IDAT;
+         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+
+         if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
+            png_chunk_benign_error(png_ptr, "Extra compressed data");
+         break;
+      }
+
+      if (ret != Z_OK)
+      {
+         png_zstream_error(png_ptr, ret);
+
+         if (output != NULL)
+            png_chunk_error(png_ptr, png_ptr->zstream.msg);
+
+         else /* checking */
+         {
+            png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
+            return;
+         }
+      }
+   } while (avail_out > 0);
+
+   if (avail_out > 0)
+   {
+      /* The stream ended before the image; this is the same as too few IDATs so
+       * should be handled the same way.
+       */
+      if (output != NULL)
+         png_error(png_ptr, "Not enough image data");
+
+      else /* the deflate stream contained extra data */
+         png_chunk_benign_error(png_ptr, "Too much image data");
+   }
+}
+
+void /* PRIVATE */
+png_read_finish_IDAT(png_structrp png_ptr)
+{
+   /* We don't need any more data and the stream should have ended, however the
+    * LZ end code may actually not have been processed.  In this case we must
+    * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
+    * may still remain to be consumed.
+    */
+   if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+   {
+      /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
+       * the compressed stream, but the stream may be damaged too, so even after
+       * this call we may need to terminate the zstream ownership.
+       */
+      png_read_IDAT_data(png_ptr, NULL, 0);
+      png_ptr->zstream.next_out = NULL; /* safety */
+
+      /* Now clear everything out for safety; the following may not have been
+       * done.
+       */
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+      {
+         png_ptr->mode |= PNG_AFTER_IDAT;
+         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+      }
+   }
+
+   /* If the zstream has not been released do it now *and* terminate the reading
+    * of the final IDAT chunk.
+    */
+   if (png_ptr->zowner == png_IDAT)
+   {
+      /* Always do this; the pointers otherwise point into the read buffer. */
+      png_ptr->zstream.next_in = NULL;
+      png_ptr->zstream.avail_in = 0;
+
+      /* Now we no longer own the zstream. */
+      png_ptr->zowner = 0;
+
+      /* The slightly weird semantics of the sequential IDAT reading is that we
+       * are always in or at the end of an IDAT chunk, so we always need to do a
+       * crc_finish here.  If idat_size is non-zero we also need to read the
+       * spurious bytes at the end of the chunk now.
+       */
+      (void)png_crc_finish(png_ptr, png_ptr->idat_size);
+   }
+}
+
+void /* PRIVATE */
+png_read_finish_row(png_structrp png_ptr)
+{
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+
+   png_debug(1, "in png_read_finish_row");
+   png_ptr->row_number++;
+   if (png_ptr->row_number < png_ptr->num_rows)
+      return;
+
+   if (png_ptr->interlaced != 0)
+   {
+      png_ptr->row_number = 0;
+
+      /* TO DO: don't do this if prev_row isn't needed (requires
+       * read-ahead of the next row's filter byte.
+       */
+      memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+      do
+      {
+         png_ptr->pass++;
+
+         if (png_ptr->pass >= 7)
+            break;
+
+         png_ptr->iwidth = (png_ptr->width +
+            png_pass_inc[png_ptr->pass] - 1 -
+            png_pass_start[png_ptr->pass]) /
+            png_pass_inc[png_ptr->pass];
+
+         if ((png_ptr->transformations & PNG_INTERLACE) == 0)
+         {
+            png_ptr->num_rows = (png_ptr->height +
+                png_pass_yinc[png_ptr->pass] - 1 -
+                png_pass_ystart[png_ptr->pass]) /
+                png_pass_yinc[png_ptr->pass];
+         }
+
+         else  /* if (png_ptr->transformations & PNG_INTERLACE) */
+            break; /* libpng deinterlacing sees every row */
+
+      } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
+
+      if (png_ptr->pass < 7)
+         return;
+   }
+
+   /* Here after at the end of the last row of the last pass. */
+   png_read_finish_IDAT(png_ptr);
+}
+#endif /* SEQUENTIAL_READ */
+
+void /* PRIVATE */
+png_read_start_row(png_structrp png_ptr)
+{
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+
+   unsigned int max_pixel_depth;
+   size_t row_bytes;
+
+   png_debug(1, "in png_read_start_row");
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+   png_init_read_transformations(png_ptr);
+#endif
+   if (png_ptr->interlaced != 0)
+   {
+      if ((png_ptr->transformations & PNG_INTERLACE) == 0)
+         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+             png_pass_ystart[0]) / png_pass_yinc[0];
+
+      else
+         png_ptr->num_rows = png_ptr->height;
+
+      png_ptr->iwidth = (png_ptr->width +
+          png_pass_inc[png_ptr->pass] - 1 -
+          png_pass_start[png_ptr->pass]) /
+          png_pass_inc[png_ptr->pass];
+   }
+
+   else
+   {
+      png_ptr->num_rows = png_ptr->height;
+      png_ptr->iwidth = png_ptr->width;
+   }
+
+   max_pixel_depth = (unsigned int)png_ptr->pixel_depth;
+
+   /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
+    * calculations to calculate the final pixel depth, then
+    * png_do_read_transforms actually does the transforms.  This means that the
+    * code which effectively calculates this value is actually repeated in three
+    * separate places.  They must all match.  Innocent changes to the order of
+    * transformations can and will break libpng in a way that causes memory
+    * overwrites.
+    *
+    * TODO: fix this.
+    */
+#ifdef PNG_READ_PACK_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
+      max_pixel_depth = 8;
+#endif
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         if (png_ptr->num_trans != 0)
+            max_pixel_depth = 32;
+
+         else
+            max_pixel_depth = 24;
+      }
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (max_pixel_depth < 8)
+            max_pixel_depth = 8;
+
+         if (png_ptr->num_trans != 0)
+            max_pixel_depth *= 2;
+      }
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+      {
+         if (png_ptr->num_trans != 0)
+         {
+            max_pixel_depth *= 4;
+            max_pixel_depth /= 3;
+         }
+      }
+   }
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
+   {
+#  ifdef PNG_READ_EXPAND_SUPPORTED
+      /* In fact it is an error if it isn't supported, but checking is
+       * the safe way.
+       */
+      if ((png_ptr->transformations & PNG_EXPAND) != 0)
+      {
+         if (png_ptr->bit_depth < 16)
+            max_pixel_depth *= 2;
+      }
+      else
+#  endif
+      png_ptr->transformations &= ~PNG_EXPAND_16;
+   }
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+   if ((png_ptr->transformations & (PNG_FILLER)) != 0)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (max_pixel_depth <= 8)
+            max_pixel_depth = 16;
+
+         else
+            max_pixel_depth = 32;
+      }
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+         png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         if (max_pixel_depth <= 32)
+            max_pixel_depth = 32;
+
+         else
+            max_pixel_depth = 64;
+      }
+   }
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
+   {
+      if (
+#ifdef PNG_READ_EXPAND_SUPPORTED
+          (png_ptr->num_trans != 0 &&
+          (png_ptr->transformations & PNG_EXPAND) != 0) ||
+#endif
+#ifdef PNG_READ_FILLER_SUPPORTED
+          (png_ptr->transformations & (PNG_FILLER)) != 0 ||
+#endif
+          png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (max_pixel_depth <= 16)
+            max_pixel_depth = 32;
+
+         else
+            max_pixel_depth = 64;
+      }
+
+      else
+      {
+         if (max_pixel_depth <= 8)
+         {
+            if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+               max_pixel_depth = 32;
+
+            else
+               max_pixel_depth = 24;
+         }
+
+         else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            max_pixel_depth = 64;
+
+         else
+            max_pixel_depth = 48;
+      }
+   }
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
+defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+   {
+      unsigned int user_pixel_depth = png_ptr->user_transform_depth *
+         png_ptr->user_transform_channels;
+
+      if (user_pixel_depth > max_pixel_depth)
+         max_pixel_depth = user_pixel_depth;
+   }
+#endif
+
+   /* This value is stored in png_struct and double checked in the row read
+    * code.
+    */
+   png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
+   png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
+
+   /* Align the width on the next larger 8 pixels.  Mainly used
+    * for interlacing
+    */
+   row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
+   /* Calculate the maximum bytes needed, adding a byte and a pixel
+    * for safety's sake
+    */
+   row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
+       1 + ((max_pixel_depth + 7) >> 3U);
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (row_bytes > (png_uint_32)65536L)
+      png_error(png_ptr, "This image requires a row greater than 64KB");
+#endif
+
+   if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
+   {
+      png_free(png_ptr, png_ptr->big_row_buf);
+      png_free(png_ptr, png_ptr->big_prev_row);
+
+      if (png_ptr->interlaced != 0)
+         png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
+             row_bytes + 48);
+
+      else
+         png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
+
+      png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
+
+#ifdef PNG_ALIGNED_MEMORY_SUPPORTED
+      /* Use 16-byte aligned memory for row_buf with at least 16 bytes
+       * of padding before and after row_buf; treat prev_row similarly.
+       * NOTE: the alignment is to the start of the pixels, one beyond the start
+       * of the buffer, because of the filter byte.  Prior to libpng 1.5.6 this
+       * was incorrect; the filter byte was aligned, which had the exact
+       * opposite effect of that intended.
+       */
+      {
+         png_bytep temp = png_ptr->big_row_buf + 32;
+         int extra = (int)((temp - (png_bytep)0) & 0x0f);
+         png_ptr->row_buf = temp - extra - 1/*filter byte*/;
+
+         temp = png_ptr->big_prev_row + 32;
+         extra = (int)((temp - (png_bytep)0) & 0x0f);
+         png_ptr->prev_row = temp - extra - 1/*filter byte*/;
+      }
+
+#else
+      /* Use 31 bytes of padding before and 17 bytes after row_buf. */
+      png_ptr->row_buf = png_ptr->big_row_buf + 31;
+      png_ptr->prev_row = png_ptr->big_prev_row + 31;
+#endif
+      png_ptr->old_big_row_buf_size = row_bytes + 48;
+   }
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (png_ptr->rowbytes > 65535)
+      png_error(png_ptr, "This image requires a row greater than 64KB");
+
+#endif
+   if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
+      png_error(png_ptr, "Row has too many bytes to allocate in memory");
+
+   memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+   png_debug1(3, "width = %u,", png_ptr->width);
+   png_debug1(3, "height = %u,", png_ptr->height);
+   png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
+   png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
+   png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
+   png_debug1(3, "irowbytes = %lu",
+       (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
+
+   /* The sequential reader needs a buffer for IDAT, but the progressive reader
+    * does not, so free the read buffer now regardless; the sequential reader
+    * reallocates it on demand.
+    */
+   if (png_ptr->read_buffer != NULL)
+   {
+      png_bytep buffer = png_ptr->read_buffer;
+
+      png_ptr->read_buffer_size = 0;
+      png_ptr->read_buffer = NULL;
+      png_free(png_ptr, buffer);
+   }
+
+   /* Finally claim the zstream for the inflate of the IDAT data, use the bits
+    * value from the stream (note that this will result in a fatal error if the
+    * IDAT stream has a bogus deflate header window_bits value, but this should
+    * not be happening any longer!)
+    */
+   if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
+      png_error(png_ptr, png_ptr->zstream.msg);
+
+   png_ptr->flags |= PNG_FLAG_ROW_INIT;
+}
+#endif /* READ */
diff --git a/extern/libpng/pngset.c b/extern/libpng/pngset.c
new file mode 100644
index 0000000000..ec75dbe369
--- /dev/null
+++ b/extern/libpng/pngset.c
@@ -0,0 +1,1802 @@
+
+/* pngset.c - storage of image information into info struct
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * The functions here are used during reads to store data from the file
+ * into the info struct, and during writes to store application data
+ * into the info struct for writing into the file.  This abstracts the
+ * info struct and allows us to change the structure in the future.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+#ifdef PNG_bKGD_SUPPORTED
+void PNGAPI
+png_set_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_color_16p background)
+{
+   png_debug1(1, "in %s storage function", "bKGD");
+
+   if (png_ptr == NULL || info_ptr == NULL || background == NULL)
+      return;
+
+   info_ptr->background = *background;
+   info_ptr->valid |= PNG_INFO_bKGD;
+}
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+void PNGFAPI
+png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
+    png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
+    png_fixed_point blue_x, png_fixed_point blue_y)
+{
+   png_xy xy;
+
+   png_debug1(1, "in %s storage function", "cHRM fixed");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   xy.redx = red_x;
+   xy.redy = red_y;
+   xy.greenx = green_x;
+   xy.greeny = green_y;
+   xy.bluex = blue_x;
+   xy.bluey = blue_y;
+   xy.whitex = white_x;
+   xy.whitey = white_y;
+
+   if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy,
+       2/* override with app values*/) != 0)
+      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+void PNGFAPI
+png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_fixed_point int_red_X, png_fixed_point int_red_Y,
+    png_fixed_point int_red_Z, png_fixed_point int_green_X,
+    png_fixed_point int_green_Y, png_fixed_point int_green_Z,
+    png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
+    png_fixed_point int_blue_Z)
+{
+   png_XYZ XYZ;
+
+   png_debug1(1, "in %s storage function", "cHRM XYZ fixed");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   XYZ.red_X = int_red_X;
+   XYZ.red_Y = int_red_Y;
+   XYZ.red_Z = int_red_Z;
+   XYZ.green_X = int_green_X;
+   XYZ.green_Y = int_green_Y;
+   XYZ.green_Z = int_green_Z;
+   XYZ.blue_X = int_blue_X;
+   XYZ.blue_Y = int_blue_Y;
+   XYZ.blue_Z = int_blue_Z;
+
+   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
+       &XYZ, 2) != 0)
+      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
+    double white_x, double white_y, double red_x, double red_y,
+    double green_x, double green_y, double blue_x, double blue_y)
+{
+   png_set_cHRM_fixed(png_ptr, info_ptr,
+       png_fixed(png_ptr, white_x, "cHRM White X"),
+       png_fixed(png_ptr, white_y, "cHRM White Y"),
+       png_fixed(png_ptr, red_x, "cHRM Red X"),
+       png_fixed(png_ptr, red_y, "cHRM Red Y"),
+       png_fixed(png_ptr, green_x, "cHRM Green X"),
+       png_fixed(png_ptr, green_y, "cHRM Green Y"),
+       png_fixed(png_ptr, blue_x, "cHRM Blue X"),
+       png_fixed(png_ptr, blue_y, "cHRM Blue Y"));
+}
+
+void PNGAPI
+png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X,
+    double red_Y, double red_Z, double green_X, double green_Y, double green_Z,
+    double blue_X, double blue_Y, double blue_Z)
+{
+   png_set_cHRM_XYZ_fixed(png_ptr, info_ptr,
+       png_fixed(png_ptr, red_X, "cHRM Red X"),
+       png_fixed(png_ptr, red_Y, "cHRM Red Y"),
+       png_fixed(png_ptr, red_Z, "cHRM Red Z"),
+       png_fixed(png_ptr, green_X, "cHRM Green X"),
+       png_fixed(png_ptr, green_Y, "cHRM Green Y"),
+       png_fixed(png_ptr, green_Z, "cHRM Green Z"),
+       png_fixed(png_ptr, blue_X, "cHRM Blue X"),
+       png_fixed(png_ptr, blue_Y, "cHRM Blue Y"),
+       png_fixed(png_ptr, blue_Z, "cHRM Blue Z"));
+}
+#  endif /* FLOATING_POINT */
+
+#endif /* cHRM */
+
+#ifdef PNG_eXIf_SUPPORTED
+void PNGAPI
+png_set_eXIf(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_bytep eXIf_buf)
+{
+  png_warning(png_ptr, "png_set_eXIf does not work; use png_set_eXIf_1");
+  PNG_UNUSED(info_ptr)
+  PNG_UNUSED(eXIf_buf)
+}
+
+void PNGAPI
+png_set_eXIf_1(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_uint_32 num_exif, png_bytep eXIf_buf)
+{
+   int i;
+
+   png_debug1(1, "in %s storage function", "eXIf");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (info_ptr->exif)
+   {
+      png_free(png_ptr, info_ptr->exif);
+      info_ptr->exif = NULL;
+   }
+
+   info_ptr->num_exif = num_exif;
+
+   info_ptr->exif = png_voidcast(png_bytep, png_malloc_warn(png_ptr,
+       info_ptr->num_exif));
+
+   if (info_ptr->exif == NULL)
+   {
+      png_warning(png_ptr, "Insufficient memory for eXIf chunk data");
+      return;
+   }
+
+   info_ptr->free_me |= PNG_FREE_EXIF;
+
+   for (i = 0; i < (int) info_ptr->num_exif; i++)
+      info_ptr->exif[i] = eXIf_buf[i];
+
+   info_ptr->valid |= PNG_INFO_eXIf;
+}
+#endif /* eXIf */
+
+#ifdef PNG_gAMA_SUPPORTED
+void PNGFAPI
+png_set_gAMA_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_fixed_point file_gamma)
+{
+   png_debug1(1, "in %s storage function", "gAMA");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_colorspace_set_gamma(png_ptr, &info_ptr->colorspace, file_gamma);
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_gAMA(png_const_structrp png_ptr, png_inforp info_ptr, double file_gamma)
+{
+   png_set_gAMA_fixed(png_ptr, info_ptr, png_fixed(png_ptr, file_gamma,
+       "png_set_gAMA"));
+}
+#  endif
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+void PNGAPI
+png_set_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_uint_16p hist)
+{
+   int i;
+
+   png_debug1(1, "in %s storage function", "hIST");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (info_ptr->num_palette == 0 || info_ptr->num_palette
+       > PNG_MAX_PALETTE_LENGTH)
+   {
+      png_warning(png_ptr,
+          "Invalid palette size, hIST allocation skipped");
+
+      return;
+   }
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0);
+
+   /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in
+    * version 1.2.1
+    */
+   info_ptr->hist = png_voidcast(png_uint_16p, png_malloc_warn(png_ptr,
+       PNG_MAX_PALETTE_LENGTH * (sizeof (png_uint_16))));
+
+   if (info_ptr->hist == NULL)
+   {
+      png_warning(png_ptr, "Insufficient memory for hIST chunk data");
+
+      return;
+   }
+
+   info_ptr->free_me |= PNG_FREE_HIST;
+
+   for (i = 0; i < info_ptr->num_palette; i++)
+      info_ptr->hist[i] = hist[i];
+
+   info_ptr->valid |= PNG_INFO_hIST;
+}
+#endif
+
+void PNGAPI
+png_set_IHDR(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_uint_32 width, png_uint_32 height, int bit_depth,
+    int color_type, int interlace_type, int compression_type,
+    int filter_type)
+{
+   png_debug1(1, "in %s storage function", "IHDR");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->width = width;
+   info_ptr->height = height;
+   info_ptr->bit_depth = (png_byte)bit_depth;
+   info_ptr->color_type = (png_byte)color_type;
+   info_ptr->compression_type = (png_byte)compression_type;
+   info_ptr->filter_type = (png_byte)filter_type;
+   info_ptr->interlace_type = (png_byte)interlace_type;
+
+   png_check_IHDR (png_ptr, info_ptr->width, info_ptr->height,
+       info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
+       info_ptr->compression_type, info_ptr->filter_type);
+
+   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      info_ptr->channels = 1;
+
+   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      info_ptr->channels = 3;
+
+   else
+      info_ptr->channels = 1;
+
+   if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      info_ptr->channels++;
+
+   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
+
+   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
+}
+
+#ifdef PNG_oFFs_SUPPORTED
+void PNGAPI
+png_set_oFFs(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_int_32 offset_x, png_int_32 offset_y, int unit_type)
+{
+   png_debug1(1, "in %s storage function", "oFFs");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->x_offset = offset_x;
+   info_ptr->y_offset = offset_y;
+   info_ptr->offset_unit_type = (png_byte)unit_type;
+   info_ptr->valid |= PNG_INFO_oFFs;
+}
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+void PNGAPI
+png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type,
+    int nparams, png_const_charp units, png_charpp params)
+{
+   size_t length;
+   int i;
+
+   png_debug1(1, "in %s storage function", "pCAL");
+
+   if (png_ptr == NULL || info_ptr == NULL || purpose == NULL || units == NULL
+       || (nparams > 0 && params == NULL))
+      return;
+
+   length = strlen(purpose) + 1;
+   png_debug1(3, "allocating purpose for info (%lu bytes)",
+       (unsigned long)length);
+
+   /* TODO: validate format of calibration name and unit name */
+
+   /* Check that the type matches the specification. */
+   if (type < 0 || type > 3)
+   {
+      png_chunk_report(png_ptr, "Invalid pCAL equation type",
+            PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   if (nparams < 0 || nparams > 255)
+   {
+      png_chunk_report(png_ptr, "Invalid pCAL parameter count",
+            PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   /* Validate params[nparams] */
+   for (i=0; i<nparams; ++i)
+   {
+      if (params[i] == NULL ||
+          !png_check_fp_string(params[i], strlen(params[i])))
+      {
+         png_chunk_report(png_ptr, "Invalid format for pCAL parameter",
+               PNG_CHUNK_WRITE_ERROR);
+         return;
+      }
+   }
+
+   info_ptr->pcal_purpose = png_voidcast(png_charp,
+       png_malloc_warn(png_ptr, length));
+
+   if (info_ptr->pcal_purpose == NULL)
+   {
+      png_chunk_report(png_ptr, "Insufficient memory for pCAL purpose",
+            PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   memcpy(info_ptr->pcal_purpose, purpose, length);
+
+   png_debug(3, "storing X0, X1, type, and nparams in info");
+   info_ptr->pcal_X0 = X0;
+   info_ptr->pcal_X1 = X1;
+   info_ptr->pcal_type = (png_byte)type;
+   info_ptr->pcal_nparams = (png_byte)nparams;
+
+   length = strlen(units) + 1;
+   png_debug1(3, "allocating units for info (%lu bytes)",
+       (unsigned long)length);
+
+   info_ptr->pcal_units = png_voidcast(png_charp,
+       png_malloc_warn(png_ptr, length));
+
+   if (info_ptr->pcal_units == NULL)
+   {
+      png_warning(png_ptr, "Insufficient memory for pCAL units");
+
+      return;
+   }
+
+   memcpy(info_ptr->pcal_units, units, length);
+
+   info_ptr->pcal_params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
+       (size_t)(((unsigned int)nparams + 1) * (sizeof (png_charp)))));
+
+   if (info_ptr->pcal_params == NULL)
+   {
+      png_warning(png_ptr, "Insufficient memory for pCAL params");
+
+      return;
+   }
+
+   memset(info_ptr->pcal_params, 0, ((unsigned int)nparams + 1) *
+       (sizeof (png_charp)));
+
+   for (i = 0; i < nparams; i++)
+   {
+      length = strlen(params[i]) + 1;
+      png_debug2(3, "allocating parameter %d for info (%lu bytes)", i,
+          (unsigned long)length);
+
+      info_ptr->pcal_params[i] = (png_charp)png_malloc_warn(png_ptr, length);
+
+      if (info_ptr->pcal_params[i] == NULL)
+      {
+         png_warning(png_ptr, "Insufficient memory for pCAL parameter");
+
+         return;
+      }
+
+      memcpy(info_ptr->pcal_params[i], params[i], length);
+   }
+
+   info_ptr->valid |= PNG_INFO_pCAL;
+   info_ptr->free_me |= PNG_FREE_PCAL;
+}
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+void PNGAPI
+png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
+    int unit, png_const_charp swidth, png_const_charp sheight)
+{
+   size_t lengthw = 0, lengthh = 0;
+
+   png_debug1(1, "in %s storage function", "sCAL");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* Double check the unit (should never get here with an invalid
+    * unit unless this is an API call.)
+    */
+   if (unit != 1 && unit != 2)
+      png_error(png_ptr, "Invalid sCAL unit");
+
+   if (swidth == NULL || (lengthw = strlen(swidth)) == 0 ||
+       swidth[0] == 45 /* '-' */ || !png_check_fp_string(swidth, lengthw))
+      png_error(png_ptr, "Invalid sCAL width");
+
+   if (sheight == NULL || (lengthh = strlen(sheight)) == 0 ||
+       sheight[0] == 45 /* '-' */ || !png_check_fp_string(sheight, lengthh))
+      png_error(png_ptr, "Invalid sCAL height");
+
+   info_ptr->scal_unit = (png_byte)unit;
+
+   ++lengthw;
+
+   png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthw);
+
+   info_ptr->scal_s_width = png_voidcast(png_charp,
+       png_malloc_warn(png_ptr, lengthw));
+
+   if (info_ptr->scal_s_width == NULL)
+   {
+      png_warning(png_ptr, "Memory allocation failed while processing sCAL");
+
+      return;
+   }
+
+   memcpy(info_ptr->scal_s_width, swidth, lengthw);
+
+   ++lengthh;
+
+   png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthh);
+
+   info_ptr->scal_s_height = png_voidcast(png_charp,
+       png_malloc_warn(png_ptr, lengthh));
+
+   if (info_ptr->scal_s_height == NULL)
+   {
+      png_free (png_ptr, info_ptr->scal_s_width);
+      info_ptr->scal_s_width = NULL;
+
+      png_warning(png_ptr, "Memory allocation failed while processing sCAL");
+
+      return;
+   }
+
+   memcpy(info_ptr->scal_s_height, sheight, lengthh);
+
+   info_ptr->valid |= PNG_INFO_sCAL;
+   info_ptr->free_me |= PNG_FREE_SCAL;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
+    double width, double height)
+{
+   png_debug1(1, "in %s storage function", "sCAL");
+
+   /* Check the arguments. */
+   if (width <= 0)
+      png_warning(png_ptr, "Invalid sCAL width ignored");
+
+   else if (height <= 0)
+      png_warning(png_ptr, "Invalid sCAL height ignored");
+
+   else
+   {
+      /* Convert 'width' and 'height' to ASCII. */
+      char swidth[PNG_sCAL_MAX_DIGITS+1];
+      char sheight[PNG_sCAL_MAX_DIGITS+1];
+
+      png_ascii_from_fp(png_ptr, swidth, (sizeof swidth), width,
+          PNG_sCAL_PRECISION);
+      png_ascii_from_fp(png_ptr, sheight, (sizeof sheight), height,
+          PNG_sCAL_PRECISION);
+
+      png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
+   }
+}
+#  endif
+
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL_fixed(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
+    png_fixed_point width, png_fixed_point height)
+{
+   png_debug1(1, "in %s storage function", "sCAL");
+
+   /* Check the arguments. */
+   if (width <= 0)
+      png_warning(png_ptr, "Invalid sCAL width ignored");
+
+   else if (height <= 0)
+      png_warning(png_ptr, "Invalid sCAL height ignored");
+
+   else
+   {
+      /* Convert 'width' and 'height' to ASCII. */
+      char swidth[PNG_sCAL_MAX_DIGITS+1];
+      char sheight[PNG_sCAL_MAX_DIGITS+1];
+
+      png_ascii_from_fixed(png_ptr, swidth, (sizeof swidth), width);
+      png_ascii_from_fixed(png_ptr, sheight, (sizeof sheight), height);
+
+      png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
+   }
+}
+#  endif
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+void PNGAPI
+png_set_pHYs(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_uint_32 res_x, png_uint_32 res_y, int unit_type)
+{
+   png_debug1(1, "in %s storage function", "pHYs");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->x_pixels_per_unit = res_x;
+   info_ptr->y_pixels_per_unit = res_y;
+   info_ptr->phys_unit_type = (png_byte)unit_type;
+   info_ptr->valid |= PNG_INFO_pHYs;
+}
+#endif
+
+void PNGAPI
+png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
+    png_const_colorp palette, int num_palette)
+{
+
+   png_uint_32 max_palette_length;
+
+   png_debug1(1, "in %s storage function", "PLTE");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   max_palette_length = (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
+      (1 << info_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
+
+   if (num_palette < 0 || num_palette > (int) max_palette_length)
+   {
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+         png_error(png_ptr, "Invalid palette length");
+
+      else
+      {
+         png_warning(png_ptr, "Invalid palette length");
+
+         return;
+      }
+   }
+
+   if ((num_palette > 0 && palette == NULL) ||
+      (num_palette == 0
+#        ifdef PNG_MNG_FEATURES_SUPPORTED
+            && (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0
+#        endif
+      ))
+   {
+      png_error(png_ptr, "Invalid palette");
+   }
+
+   /* It may not actually be necessary to set png_ptr->palette here;
+    * we do it for backward compatibility with the way the png_handle_tRNS
+    * function used to do the allocation.
+    *
+    * 1.6.0: the above statement appears to be incorrect; something has to set
+    * the palette inside png_struct on read.
+    */
+   png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0);
+
+   /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
+    * of num_palette entries, in case of an invalid PNG file or incorrect
+    * call to png_set_PLTE() with too-large sample values.
+    */
+   png_ptr->palette = png_voidcast(png_colorp, png_calloc(png_ptr,
+       PNG_MAX_PALETTE_LENGTH * (sizeof (png_color))));
+
+   if (num_palette > 0)
+      memcpy(png_ptr->palette, palette, (unsigned int)num_palette *
+          (sizeof (png_color)));
+   info_ptr->palette = png_ptr->palette;
+   info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;
+
+   info_ptr->free_me |= PNG_FREE_PLTE;
+
+   info_ptr->valid |= PNG_INFO_PLTE;
+}
+
+#ifdef PNG_sBIT_SUPPORTED
+void PNGAPI
+png_set_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_color_8p sig_bit)
+{
+   png_debug1(1, "in %s storage function", "sBIT");
+
+   if (png_ptr == NULL || info_ptr == NULL || sig_bit == NULL)
+      return;
+
+   info_ptr->sig_bit = *sig_bit;
+   info_ptr->valid |= PNG_INFO_sBIT;
+}
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+void PNGAPI
+png_set_sRGB(png_const_structrp png_ptr, png_inforp info_ptr, int srgb_intent)
+{
+   png_debug1(1, "in %s storage function", "sRGB");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   (void)png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent);
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+void PNGAPI
+png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
+    int srgb_intent)
+{
+   png_debug1(1, "in %s storage function", "sRGB_gAMA_and_cHRM");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
+       srgb_intent) != 0)
+   {
+      /* This causes the gAMA and cHRM to be written too */
+      info_ptr->colorspace.flags |=
+         PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
+   }
+
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+#endif /* sRGB */
+
+
+#ifdef PNG_iCCP_SUPPORTED
+void PNGAPI
+png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_charp name, int compression_type,
+    png_const_bytep profile, png_uint_32 proflen)
+{
+   png_charp new_iccp_name;
+   png_bytep new_iccp_profile;
+   size_t length;
+
+   png_debug1(1, "in %s storage function", "iCCP");
+
+   if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL)
+      return;
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+      png_app_error(png_ptr, "Invalid iCCP compression method");
+
+   /* Set the colorspace first because this validates the profile; do not
+    * override previously set app cHRM or gAMA here (because likely as not the
+    * application knows better than libpng what the correct values are.)  Pass
+    * the info_ptr color_type field to png_colorspace_set_ICC because in the
+    * write case it has not yet been stored in png_ptr.
+    */
+   {
+      int result = png_colorspace_set_ICC(png_ptr, &info_ptr->colorspace, name,
+          proflen, profile, info_ptr->color_type);
+
+      png_colorspace_sync_info(png_ptr, info_ptr);
+
+      /* Don't do any of the copying if the profile was bad, or inconsistent. */
+      if (result == 0)
+         return;
+
+      /* But do write the gAMA and cHRM chunks from the profile. */
+      info_ptr->colorspace.flags |=
+         PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
+   }
+
+   length = strlen(name)+1;
+   new_iccp_name = png_voidcast(png_charp, png_malloc_warn(png_ptr, length));
+
+   if (new_iccp_name == NULL)
+   {
+      png_benign_error(png_ptr, "Insufficient memory to process iCCP chunk");
+
+      return;
+   }
+
+   memcpy(new_iccp_name, name, length);
+   new_iccp_profile = png_voidcast(png_bytep,
+       png_malloc_warn(png_ptr, proflen));
+
+   if (new_iccp_profile == NULL)
+   {
+      png_free(png_ptr, new_iccp_name);
+      png_benign_error(png_ptr,
+          "Insufficient memory to process iCCP profile");
+
+      return;
+   }
+
+   memcpy(new_iccp_profile, profile, proflen);
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0);
+
+   info_ptr->iccp_proflen = proflen;
+   info_ptr->iccp_name = new_iccp_name;
+   info_ptr->iccp_profile = new_iccp_profile;
+   info_ptr->free_me |= PNG_FREE_ICCP;
+   info_ptr->valid |= PNG_INFO_iCCP;
+}
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+void PNGAPI
+png_set_text(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_textp text_ptr, int num_text)
+{
+   int ret;
+   ret = png_set_text_2(png_ptr, info_ptr, text_ptr, num_text);
+
+   if (ret != 0)
+      png_error(png_ptr, "Insufficient memory to store text");
+}
+
+int /* PRIVATE */
+png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_textp text_ptr, int num_text)
+{
+   int i;
+
+   png_debug1(1, "in %lx storage function", png_ptr == NULL ? 0xabadca11U :
+      (unsigned long)png_ptr->chunk_name);
+
+   if (png_ptr == NULL || info_ptr == NULL || num_text <= 0 || text_ptr == NULL)
+      return(0);
+
+   /* Make sure we have enough space in the "text" array in info_struct
+    * to hold all of the incoming text_ptr objects.  This compare can't overflow
+    * because max_text >= num_text (anyway, subtract of two positive integers
+    * can't overflow in any case.)
+    */
+   if (num_text > info_ptr->max_text - info_ptr->num_text)
+   {
+      int old_num_text = info_ptr->num_text;
+      int max_text;
+      png_textp new_text = NULL;
+
+      /* Calculate an appropriate max_text, checking for overflow. */
+      max_text = old_num_text;
+      if (num_text <= INT_MAX - max_text)
+      {
+         max_text += num_text;
+
+         /* Round up to a multiple of 8 */
+         if (max_text < INT_MAX-8)
+            max_text = (max_text + 8) & ~0x7;
+
+         else
+            max_text = INT_MAX;
+
+         /* Now allocate a new array and copy the old members in; this does all
+          * the overflow checks.
+          */
+         new_text = png_voidcast(png_textp,png_realloc_array(png_ptr,
+             info_ptr->text, old_num_text, max_text-old_num_text,
+             sizeof *new_text));
+      }
+
+      if (new_text == NULL)
+      {
+         png_chunk_report(png_ptr, "too many text chunks",
+             PNG_CHUNK_WRITE_ERROR);
+
+         return 1;
+      }
+
+      png_free(png_ptr, info_ptr->text);
+
+      info_ptr->text = new_text;
+      info_ptr->free_me |= PNG_FREE_TEXT;
+      info_ptr->max_text = max_text;
+      /* num_text is adjusted below as the entries are copied in */
+
+      png_debug1(3, "allocated %d entries for info_ptr->text", max_text);
+   }
+
+   for (i = 0; i < num_text; i++)
+   {
+      size_t text_length, key_len;
+      size_t lang_len, lang_key_len;
+      png_textp textp = &(info_ptr->text[info_ptr->num_text]);
+
+      if (text_ptr[i].key == NULL)
+          continue;
+
+      if (text_ptr[i].compression < PNG_TEXT_COMPRESSION_NONE ||
+          text_ptr[i].compression >= PNG_TEXT_COMPRESSION_LAST)
+      {
+         png_chunk_report(png_ptr, "text compression mode is out of range",
+             PNG_CHUNK_WRITE_ERROR);
+         continue;
+      }
+
+      key_len = strlen(text_ptr[i].key);
+
+      if (text_ptr[i].compression <= 0)
+      {
+         lang_len = 0;
+         lang_key_len = 0;
+      }
+
+      else
+#  ifdef PNG_iTXt_SUPPORTED
+      {
+         /* Set iTXt data */
+
+         if (text_ptr[i].lang != NULL)
+            lang_len = strlen(text_ptr[i].lang);
+
+         else
+            lang_len = 0;
+
+         if (text_ptr[i].lang_key != NULL)
+            lang_key_len = strlen(text_ptr[i].lang_key);
+
+         else
+            lang_key_len = 0;
+      }
+#  else /* iTXt */
+      {
+         png_chunk_report(png_ptr, "iTXt chunk not supported",
+             PNG_CHUNK_WRITE_ERROR);
+         continue;
+      }
+#  endif
+
+      if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0')
+      {
+         text_length = 0;
+#  ifdef PNG_iTXt_SUPPORTED
+         if (text_ptr[i].compression > 0)
+            textp->compression = PNG_ITXT_COMPRESSION_NONE;
+
+         else
+#  endif
+            textp->compression = PNG_TEXT_COMPRESSION_NONE;
+      }
+
+      else
+      {
+         text_length = strlen(text_ptr[i].text);
+         textp->compression = text_ptr[i].compression;
+      }
+
+      textp->key = png_voidcast(png_charp,png_malloc_base(png_ptr,
+          key_len + text_length + lang_len + lang_key_len + 4));
+
+      if (textp->key == NULL)
+      {
+         png_chunk_report(png_ptr, "text chunk: out of memory",
+             PNG_CHUNK_WRITE_ERROR);
+
+         return 1;
+      }
+
+      png_debug2(2, "Allocated %lu bytes at %p in png_set_text",
+          (unsigned long)(png_uint_32)
+          (key_len + lang_len + lang_key_len + text_length + 4),
+          textp->key);
+
+      memcpy(textp->key, text_ptr[i].key, key_len);
+      *(textp->key + key_len) = '\0';
+
+      if (text_ptr[i].compression > 0)
+      {
+         textp->lang = textp->key + key_len + 1;
+         memcpy(textp->lang, text_ptr[i].lang, lang_len);
+         *(textp->lang + lang_len) = '\0';
+         textp->lang_key = textp->lang + lang_len + 1;
+         memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len);
+         *(textp->lang_key + lang_key_len) = '\0';
+         textp->text = textp->lang_key + lang_key_len + 1;
+      }
+
+      else
+      {
+         textp->lang=NULL;
+         textp->lang_key=NULL;
+         textp->text = textp->key + key_len + 1;
+      }
+
+      if (text_length != 0)
+         memcpy(textp->text, text_ptr[i].text, text_length);
+
+      *(textp->text + text_length) = '\0';
+
+#  ifdef PNG_iTXt_SUPPORTED
+      if (textp->compression > 0)
+      {
+         textp->text_length = 0;
+         textp->itxt_length = text_length;
+      }
+
+      else
+#  endif
+      {
+         textp->text_length = text_length;
+         textp->itxt_length = 0;
+      }
+
+      info_ptr->num_text++;
+      png_debug1(3, "transferred text chunk %d", info_ptr->num_text);
+   }
+
+   return(0);
+}
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+void PNGAPI
+png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_timep mod_time)
+{
+   png_debug1(1, "in %s storage function", "tIME");
+
+   if (png_ptr == NULL || info_ptr == NULL || mod_time == NULL ||
+       (png_ptr->mode & PNG_WROTE_tIME) != 0)
+      return;
+
+   if (mod_time->month == 0   || mod_time->month > 12  ||
+       mod_time->day   == 0   || mod_time->day   > 31  ||
+       mod_time->hour  > 23   || mod_time->minute > 59 ||
+       mod_time->second > 60)
+   {
+      png_warning(png_ptr, "Ignoring invalid time value");
+
+      return;
+   }
+
+   info_ptr->mod_time = *mod_time;
+   info_ptr->valid |= PNG_INFO_tIME;
+}
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+void PNGAPI
+png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
+    png_const_bytep trans_alpha, int num_trans, png_const_color_16p trans_color)
+{
+   png_debug1(1, "in %s storage function", "tRNS");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+
+      return;
+
+   if (trans_alpha != NULL)
+   {
+       /* It may not actually be necessary to set png_ptr->trans_alpha here;
+        * we do it for backward compatibility with the way the png_handle_tRNS
+        * function used to do the allocation.
+        *
+        * 1.6.0: The above statement is incorrect; png_handle_tRNS effectively
+        * relies on png_set_tRNS storing the information in png_struct
+        * (otherwise it won't be there for the code in pngrtran.c).
+        */
+
+       png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
+
+       if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
+       {
+         /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
+          info_ptr->trans_alpha = png_voidcast(png_bytep,
+              png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));
+          memcpy(info_ptr->trans_alpha, trans_alpha, (size_t)num_trans);
+       }
+       png_ptr->trans_alpha = info_ptr->trans_alpha;
+   }
+
+   if (trans_color != NULL)
+   {
+#ifdef PNG_WARNINGS_SUPPORTED
+      if (info_ptr->bit_depth < 16)
+      {
+         int sample_max = (1 << info_ptr->bit_depth) - 1;
+
+         if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
+             trans_color->gray > sample_max) ||
+             (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+             (trans_color->red > sample_max ||
+             trans_color->green > sample_max ||
+             trans_color->blue > sample_max)))
+            png_warning(png_ptr,
+                "tRNS chunk has out-of-range samples for bit_depth");
+      }
+#endif
+
+      info_ptr->trans_color = *trans_color;
+
+      if (num_trans == 0)
+         num_trans = 1;
+   }
+
+   info_ptr->num_trans = (png_uint_16)num_trans;
+
+   if (num_trans != 0)
+   {
+      info_ptr->valid |= PNG_INFO_tRNS;
+      info_ptr->free_me |= PNG_FREE_TRNS;
+   }
+}
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+void PNGAPI
+png_set_sPLT(png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)
+/*
+ *  entries        - array of png_sPLT_t structures
+ *                   to be added to the list of palettes
+ *                   in the info structure.
+ *
+ *  nentries       - number of palette structures to be
+ *                   added.
+ */
+{
+   png_sPLT_tp np;
+
+   if (png_ptr == NULL || info_ptr == NULL || nentries <= 0 || entries == NULL)
+      return;
+
+   /* Use the internal realloc function, which checks for all the possible
+    * overflows.  Notice that the parameters are (int) and (size_t)
+    */
+   np = png_voidcast(png_sPLT_tp,png_realloc_array(png_ptr,
+       info_ptr->splt_palettes, info_ptr->splt_palettes_num, nentries,
+       sizeof *np));
+
+   if (np == NULL)
+   {
+      /* Out of memory or too many chunks */
+      png_chunk_report(png_ptr, "too many sPLT chunks", PNG_CHUNK_WRITE_ERROR);
+
+      return;
+   }
+
+   png_free(png_ptr, info_ptr->splt_palettes);
+   info_ptr->splt_palettes = np;
+   info_ptr->free_me |= PNG_FREE_SPLT;
+
+   np += info_ptr->splt_palettes_num;
+
+   do
+   {
+      size_t length;
+
+      /* Skip invalid input entries */
+      if (entries->name == NULL || entries->entries == NULL)
+      {
+         /* png_handle_sPLT doesn't do this, so this is an app error */
+         png_app_error(png_ptr, "png_set_sPLT: invalid sPLT");
+         /* Just skip the invalid entry */
+         continue;
+      }
+
+      np->depth = entries->depth;
+
+      /* In the event of out-of-memory just return - there's no point keeping
+       * on trying to add sPLT chunks.
+       */
+      length = strlen(entries->name) + 1;
+      np->name = png_voidcast(png_charp, png_malloc_base(png_ptr, length));
+
+      if (np->name == NULL)
+         break;
+
+      memcpy(np->name, entries->name, length);
+
+      /* IMPORTANT: we have memory now that won't get freed if something else
+       * goes wrong; this code must free it.  png_malloc_array produces no
+       * warnings; use a png_chunk_report (below) if there is an error.
+       */
+      np->entries = png_voidcast(png_sPLT_entryp, png_malloc_array(png_ptr,
+          entries->nentries, sizeof (png_sPLT_entry)));
+
+      if (np->entries == NULL)
+      {
+         png_free(png_ptr, np->name);
+         np->name = NULL;
+         break;
+      }
+
+      np->nentries = entries->nentries;
+      /* This multiply can't overflow because png_malloc_array has already
+       * checked it when doing the allocation.
+       */
+      memcpy(np->entries, entries->entries,
+          (unsigned int)entries->nentries * sizeof (png_sPLT_entry));
+
+      /* Note that 'continue' skips the advance of the out pointer and out
+       * count, so an invalid entry is not added.
+       */
+      info_ptr->valid |= PNG_INFO_sPLT;
+      ++(info_ptr->splt_palettes_num);
+      ++np;
+      ++entries;
+   }
+   while (--nentries);
+
+   if (nentries > 0)
+      png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
+}
+#endif /* sPLT */
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+static png_byte
+check_location(png_const_structrp png_ptr, int location)
+{
+   location &= (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT);
+
+   /* New in 1.6.0; copy the location and check it.  This is an API
+    * change; previously the app had to use the
+    * png_set_unknown_chunk_location API below for each chunk.
+    */
+   if (location == 0 && (png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+   {
+      /* Write struct, so unknown chunks come from the app */
+      png_app_warning(png_ptr,
+          "png_set_unknown_chunks now expects a valid location");
+      /* Use the old behavior */
+      location = (png_byte)(png_ptr->mode &
+          (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT));
+   }
+
+   /* This need not be an internal error - if the app calls
+    * png_set_unknown_chunks on a read pointer it must get the location right.
+    */
+   if (location == 0)
+      png_error(png_ptr, "invalid location in png_set_unknown_chunks");
+
+   /* Now reduce the location to the top-most set bit by removing each least
+    * significant bit in turn.
+    */
+   while (location != (location & -location))
+      location &= ~(location & -location);
+
+   /* The cast is safe because 'location' is a bit mask and only the low four
+    * bits are significant.
+    */
+   return (png_byte)location;
+}
+
+void PNGAPI
+png_set_unknown_chunks(png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
+{
+   png_unknown_chunkp np;
+
+   if (png_ptr == NULL || info_ptr == NULL || num_unknowns <= 0 ||
+       unknowns == NULL)
+      return;
+
+   /* Check for the failure cases where support has been disabled at compile
+    * time.  This code is hardly ever compiled - it's here because
+    * STORE_UNKNOWN_CHUNKS is set by both read and write code (compiling in this
+    * code) but may be meaningless if the read or write handling of unknown
+    * chunks is not compiled in.
+    */
+#  if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \
+      defined(PNG_READ_SUPPORTED)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+      {
+         png_app_error(png_ptr, "no unknown chunk support on read");
+
+         return;
+      }
+#  endif
+#  if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \
+      defined(PNG_WRITE_SUPPORTED)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+      {
+         png_app_error(png_ptr, "no unknown chunk support on write");
+
+         return;
+      }
+#  endif
+
+   /* Prior to 1.6.0 this code used png_malloc_warn; however, this meant that
+    * unknown critical chunks could be lost with just a warning resulting in
+    * undefined behavior.  Now png_chunk_report is used to provide behavior
+    * appropriate to read or write.
+    */
+   np = png_voidcast(png_unknown_chunkp, png_realloc_array(png_ptr,
+       info_ptr->unknown_chunks, info_ptr->unknown_chunks_num, num_unknowns,
+       sizeof *np));
+
+   if (np == NULL)
+   {
+      png_chunk_report(png_ptr, "too many unknown chunks",
+          PNG_CHUNK_WRITE_ERROR);
+
+      return;
+   }
+
+   png_free(png_ptr, info_ptr->unknown_chunks);
+   info_ptr->unknown_chunks = np; /* safe because it is initialized */
+   info_ptr->free_me |= PNG_FREE_UNKN;
+
+   np += info_ptr->unknown_chunks_num;
+
+   /* Increment unknown_chunks_num each time round the loop to protect the
+    * just-allocated chunk data.
+    */
+   for (; num_unknowns > 0; --num_unknowns, ++unknowns)
+   {
+      memcpy(np->name, unknowns->name, (sizeof np->name));
+      np->name[(sizeof np->name)-1] = '\0';
+      np->location = check_location(png_ptr, unknowns->location);
+
+      if (unknowns->size == 0)
+      {
+         np->data = NULL;
+         np->size = 0;
+      }
+
+      else
+      {
+         np->data = png_voidcast(png_bytep,
+             png_malloc_base(png_ptr, unknowns->size));
+
+         if (np->data == NULL)
+         {
+            png_chunk_report(png_ptr, "unknown chunk: out of memory",
+                PNG_CHUNK_WRITE_ERROR);
+            /* But just skip storing the unknown chunk */
+            continue;
+         }
+
+         memcpy(np->data, unknowns->data, unknowns->size);
+         np->size = unknowns->size;
+      }
+
+      /* These increments are skipped on out-of-memory for the data - the
+       * unknown chunk entry gets overwritten if the png_chunk_report returns.
+       * This is correct in the read case (the chunk is just dropped.)
+       */
+      ++np;
+      ++(info_ptr->unknown_chunks_num);
+   }
+}
+
+void PNGAPI
+png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
+    int chunk, int location)
+{
+   /* This API is pretty pointless in 1.6.0 because the location can be set
+    * before the call to png_set_unknown_chunks.
+    *
+    * TODO: add a png_app_warning in 1.7
+    */
+   if (png_ptr != NULL && info_ptr != NULL && chunk >= 0 &&
+      chunk < info_ptr->unknown_chunks_num)
+   {
+      if ((location & (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT)) == 0)
+      {
+         png_app_error(png_ptr, "invalid unknown chunk location");
+         /* Fake out the pre 1.6.0 behavior: */
+         if (((unsigned int)location & PNG_HAVE_IDAT) != 0) /* undocumented! */
+            location = PNG_AFTER_IDAT;
+
+         else
+            location = PNG_HAVE_IHDR; /* also undocumented */
+      }
+
+      info_ptr->unknown_chunks[chunk].location =
+         check_location(png_ptr, location);
+   }
+}
+#endif /* STORE_UNKNOWN_CHUNKS */
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+png_uint_32 PNGAPI
+png_permit_mng_features (png_structrp png_ptr, png_uint_32 mng_features)
+{
+   png_debug(1, "in png_permit_mng_features");
+
+   if (png_ptr == NULL)
+      return 0;
+
+   png_ptr->mng_features_permitted = mng_features & PNG_ALL_MNG_FEATURES;
+
+   return png_ptr->mng_features_permitted;
+}
+#endif
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+static unsigned int
+add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep)
+{
+   unsigned int i;
+
+   /* Utility function: update the 'keep' state of a chunk if it is already in
+    * the list, otherwise add it to the list.
+    */
+   for (i=0; i<count; ++i, list += 5)
+   {
+      if (memcmp(list, add, 4) == 0)
+      {
+         list[4] = (png_byte)keep;
+
+         return count;
+      }
+   }
+
+   if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
+   {
+      ++count;
+      memcpy(list, add, 4);
+      list[4] = (png_byte)keep;
+   }
+
+   return count;
+}
+
+void PNGAPI
+png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
+    png_const_bytep chunk_list, int num_chunks_in)
+{
+   png_bytep new_list;
+   unsigned int num_chunks, old_num_chunks;
+
+   if (png_ptr == NULL)
+      return;
+
+   if (keep < 0 || keep >= PNG_HANDLE_CHUNK_LAST)
+   {
+      png_app_error(png_ptr, "png_set_keep_unknown_chunks: invalid keep");
+
+      return;
+   }
+
+   if (num_chunks_in <= 0)
+   {
+      png_ptr->unknown_default = keep;
+
+      /* '0' means just set the flags, so stop here */
+      if (num_chunks_in == 0)
+        return;
+   }
+
+   if (num_chunks_in < 0)
+   {
+      /* Ignore all unknown chunks and all chunks recognized by
+       * libpng except for IHDR, PLTE, tRNS, IDAT, and IEND
+       */
+      static const png_byte chunks_to_ignore[] = {
+         98,  75,  71,  68, '\0',  /* bKGD */
+         99,  72,  82,  77, '\0',  /* cHRM */
+        101,  88,  73, 102, '\0',  /* eXIf */
+        103,  65,  77,  65, '\0',  /* gAMA */
+        104,  73,  83,  84, '\0',  /* hIST */
+        105,  67,  67,  80, '\0',  /* iCCP */
+        105,  84,  88, 116, '\0',  /* iTXt */
+        111,  70,  70, 115, '\0',  /* oFFs */
+        112,  67,  65,  76, '\0',  /* pCAL */
+        112,  72,  89, 115, '\0',  /* pHYs */
+        115,  66,  73,  84, '\0',  /* sBIT */
+        115,  67,  65,  76, '\0',  /* sCAL */
+        115,  80,  76,  84, '\0',  /* sPLT */
+        115,  84,  69,  82, '\0',  /* sTER */
+        115,  82,  71,  66, '\0',  /* sRGB */
+        116,  69,  88, 116, '\0',  /* tEXt */
+        116,  73,  77,  69, '\0',  /* tIME */
+        122,  84,  88, 116, '\0'   /* zTXt */
+      };
+
+      chunk_list = chunks_to_ignore;
+      num_chunks = (unsigned int)/*SAFE*/(sizeof chunks_to_ignore)/5U;
+   }
+
+   else /* num_chunks_in > 0 */
+   {
+      if (chunk_list == NULL)
+      {
+         /* Prior to 1.6.0 this was silently ignored, now it is an app_error
+          * which can be switched off.
+          */
+         png_app_error(png_ptr, "png_set_keep_unknown_chunks: no chunk list");
+
+         return;
+      }
+
+      num_chunks = (unsigned int)num_chunks_in;
+   }
+
+   old_num_chunks = png_ptr->num_chunk_list;
+   if (png_ptr->chunk_list == NULL)
+      old_num_chunks = 0;
+
+   /* Since num_chunks is always restricted to UINT_MAX/5 this can't overflow.
+    */
+   if (num_chunks + old_num_chunks > UINT_MAX/5)
+   {
+      png_app_error(png_ptr, "png_set_keep_unknown_chunks: too many chunks");
+
+      return;
+   }
+
+   /* If these chunks are being reset to the default then no more memory is
+    * required because add_one_chunk above doesn't extend the list if the 'keep'
+    * parameter is the default.
+    */
+   if (keep != 0)
+   {
+      new_list = png_voidcast(png_bytep, png_malloc(png_ptr,
+          5 * (num_chunks + old_num_chunks)));
+
+      if (old_num_chunks > 0)
+         memcpy(new_list, png_ptr->chunk_list, 5*old_num_chunks);
+   }
+
+   else if (old_num_chunks > 0)
+      new_list = png_ptr->chunk_list;
+
+   else
+      new_list = NULL;
+
+   /* Add the new chunks together with each one's handling code.  If the chunk
+    * already exists the code is updated, otherwise the chunk is added to the
+    * end.  (In libpng 1.6.0 order no longer matters because this code enforces
+    * the earlier convention that the last setting is the one that is used.)
+    */
+   if (new_list != NULL)
+   {
+      png_const_bytep inlist;
+      png_bytep outlist;
+      unsigned int i;
+
+      for (i=0; i<num_chunks; ++i)
+      {
+         old_num_chunks = add_one_chunk(new_list, old_num_chunks,
+             chunk_list+5*i, keep);
+      }
+
+      /* Now remove any spurious 'default' entries. */
+      num_chunks = 0;
+      for (i=0, inlist=outlist=new_list; i<old_num_chunks; ++i, inlist += 5)
+      {
+         if (inlist[4])
+         {
+            if (outlist != inlist)
+               memcpy(outlist, inlist, 5);
+            outlist += 5;
+            ++num_chunks;
+         }
+      }
+
+      /* This means the application has removed all the specialized handling. */
+      if (num_chunks == 0)
+      {
+         if (png_ptr->chunk_list != new_list)
+            png_free(png_ptr, new_list);
+
+         new_list = NULL;
+      }
+   }
+
+   else
+      num_chunks = 0;
+
+   png_ptr->num_chunk_list = num_chunks;
+
+   if (png_ptr->chunk_list != new_list)
+   {
+      if (png_ptr->chunk_list != NULL)
+         png_free(png_ptr, png_ptr->chunk_list);
+
+      png_ptr->chunk_list = new_list;
+   }
+}
+#endif
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+void PNGAPI
+png_set_read_user_chunk_fn(png_structrp png_ptr, png_voidp user_chunk_ptr,
+    png_user_chunk_ptr read_user_chunk_fn)
+{
+   png_debug(1, "in png_set_read_user_chunk_fn");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->read_user_chunk_fn = read_user_chunk_fn;
+   png_ptr->user_chunk_ptr = user_chunk_ptr;
+}
+#endif
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+void PNGAPI
+png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_bytepp row_pointers)
+{
+   png_debug1(1, "in %s storage function", "rows");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (info_ptr->row_pointers != NULL &&
+       (info_ptr->row_pointers != row_pointers))
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
+
+   info_ptr->row_pointers = row_pointers;
+
+   if (row_pointers != NULL)
+      info_ptr->valid |= PNG_INFO_IDAT;
+}
+#endif
+
+void PNGAPI
+png_set_compression_buffer_size(png_structrp png_ptr, size_t size)
+{
+   if (png_ptr == NULL)
+      return;
+
+   if (size == 0 || size > PNG_UINT_31_MAX)
+      png_error(png_ptr, "invalid compression buffer size");
+
+#  ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+   {
+      png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
+      return;
+   }
+#  endif
+
+#  ifdef PNG_WRITE_SUPPORTED
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+   {
+      if (png_ptr->zowner != 0)
+      {
+         png_warning(png_ptr,
+             "Compression buffer size cannot be changed because it is in use");
+
+         return;
+      }
+
+#ifndef __COVERITY__
+      /* Some compilers complain that this is always false.  However, it
+       * can be true when integer overflow happens.
+       */
+      if (size > ZLIB_IO_MAX)
+      {
+         png_warning(png_ptr,
+             "Compression buffer size limited to system maximum");
+         size = ZLIB_IO_MAX; /* must fit */
+      }
+#endif
+
+      if (size < 6)
+      {
+         /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH
+          * if this is permitted.
+          */
+         png_warning(png_ptr,
+             "Compression buffer size cannot be reduced below 6");
+
+         return;
+      }
+
+      if (png_ptr->zbuffer_size != size)
+      {
+         png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
+         png_ptr->zbuffer_size = (uInt)size;
+      }
+   }
+#  endif
+}
+
+void PNGAPI
+png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      info_ptr->valid &= (unsigned int)(~mask);
+}
+
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+/* This function was added to libpng 1.2.6 */
+void PNGAPI
+png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max,
+    png_uint_32 user_height_max)
+{
+   /* Images with dimensions larger than these limits will be
+    * rejected by png_set_IHDR().  To accept any PNG datastream
+    * regardless of dimensions, set both limits to 0x7fffffff.
+    */
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->user_width_max = user_width_max;
+   png_ptr->user_height_max = user_height_max;
+}
+
+/* This function was added to libpng 1.4.0 */
+void PNGAPI
+png_set_chunk_cache_max (png_structrp png_ptr, png_uint_32 user_chunk_cache_max)
+{
+   if (png_ptr != NULL)
+      png_ptr->user_chunk_cache_max = user_chunk_cache_max;
+}
+
+/* This function was added to libpng 1.4.1 */
+void PNGAPI
+png_set_chunk_malloc_max (png_structrp png_ptr,
+    png_alloc_size_t user_chunk_malloc_max)
+{
+   if (png_ptr != NULL)
+      png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
+}
+#endif /* ?SET_USER_LIMITS */
+
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+void PNGAPI
+png_set_benign_errors(png_structrp png_ptr, int allowed)
+{
+   png_debug(1, "in png_set_benign_errors");
+
+   /* If allowed is 1, png_benign_error() is treated as a warning.
+    *
+    * If allowed is 0, png_benign_error() is treated as an error (which
+    * is the default behavior if png_set_benign_errors() is not called).
+    */
+
+   if (allowed != 0)
+      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN |
+         PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN;
+
+   else
+      png_ptr->flags &= ~(PNG_FLAG_BENIGN_ERRORS_WARN |
+         PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN);
+}
+#endif /* BENIGN_ERRORS */
+
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   /* Whether to report invalid palette index; added at libng-1.5.10.
+    * It is possible for an indexed (color-type==3) PNG file to contain
+    * pixels with invalid (out-of-range) indexes if the PLTE chunk has
+    * fewer entries than the image's bit-depth would allow. We recover
+    * from this gracefully by filling any incomplete palette with zeros
+    * (opaque black).  By default, when this occurs libpng will issue
+    * a benign error.  This API can be used to override that behavior.
+    */
+void PNGAPI
+png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
+{
+   png_debug(1, "in png_set_check_for_invalid_index");
+
+   if (allowed > 0)
+      png_ptr->num_palette_max = 0;
+
+   else
+      png_ptr->num_palette_max = -1;
+}
+#endif
+
+#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_pCAL_SUPPORTED) || \
+    defined(PNG_iCCP_SUPPORTED) || defined(PNG_sPLT_SUPPORTED)
+/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
+ * and if invalid, correct the keyword rather than discarding the entire
+ * chunk.  The PNG 1.0 specification requires keywords 1-79 characters in
+ * length, forbids leading or trailing whitespace, multiple internal spaces,
+ * and the non-break space (0x80) from ISO 8859-1.  Returns keyword length.
+ *
+ * The 'new_key' buffer must be 80 characters in size (for the keyword plus a
+ * trailing '\0').  If this routine returns 0 then there was no keyword, or a
+ * valid one could not be generated, and the caller must png_error.
+ */
+png_uint_32 /* PRIVATE */
+png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
+{
+#ifdef PNG_WARNINGS_SUPPORTED
+   png_const_charp orig_key = key;
+#endif
+   png_uint_32 key_len = 0;
+   int bad_character = 0;
+   int space = 1;
+
+   png_debug(1, "in png_check_keyword");
+
+   if (key == NULL)
+   {
+      *new_key = 0;
+      return 0;
+   }
+
+   while (*key && key_len < 79)
+   {
+      png_byte ch = (png_byte)*key++;
+
+      if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
+      {
+         *new_key++ = ch; ++key_len; space = 0;
+      }
+
+      else if (space == 0)
+      {
+         /* A space or an invalid character when one wasn't seen immediately
+          * before; output just a space.
+          */
+         *new_key++ = 32; ++key_len; space = 1;
+
+         /* If the character was not a space then it is invalid. */
+         if (ch != 32)
+            bad_character = ch;
+      }
+
+      else if (bad_character == 0)
+         bad_character = ch; /* just skip it, record the first error */
+   }
+
+   if (key_len > 0 && space != 0) /* trailing space */
+   {
+      --key_len; --new_key;
+      if (bad_character == 0)
+         bad_character = 32;
+   }
+
+   /* Terminate the keyword */
+   *new_key = 0;
+
+   if (key_len == 0)
+      return 0;
+
+#ifdef PNG_WARNINGS_SUPPORTED
+   /* Try to only output one warning per keyword: */
+   if (*key != 0) /* keyword too long */
+      png_warning(png_ptr, "keyword truncated");
+
+   else if (bad_character != 0)
+   {
+      PNG_WARNING_PARAMETERS(p)
+
+      png_warning_parameter(p, 1, orig_key);
+      png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character);
+
+      png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
+   }
+#else /* !WARNINGS */
+   PNG_UNUSED(png_ptr)
+#endif /* !WARNINGS */
+
+   return key_len;
+}
+#endif /* TEXT || pCAL || iCCP || sPLT */
+#endif /* READ || WRITE */
diff --git a/extern/libpng/pngstruct.h b/extern/libpng/pngstruct.h
new file mode 100644
index 0000000000..8bdc7ce46d
--- /dev/null
+++ b/extern/libpng/pngstruct.h
@@ -0,0 +1,489 @@
+
+/* pngstruct.h - header file for PNG reference library
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* The structure that holds the information to read and write PNG files.
+ * The only people who need to care about what is inside of this are the
+ * people who will be modifying the library for their own special needs.
+ * It should NOT be accessed directly by an application.
+ */
+
+#ifndef PNGSTRUCT_H
+#define PNGSTRUCT_H
+/* zlib.h defines the structure z_stream, an instance of which is included
+ * in this structure and is required for decompressing the LZ compressed
+ * data in PNG files.
+ */
+#ifndef ZLIB_CONST
+   /* We must ensure that zlib uses 'const' in declarations. */
+#  define ZLIB_CONST
+#endif
+#include "zlib.h"
+#ifdef const
+   /* zlib.h sometimes #defines const to nothing, undo this. */
+#  undef const
+#endif
+
+/* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
+ * with older builds.
+ */
+#if ZLIB_VERNUM < 0x1260
+#  define PNGZ_MSG_CAST(s) png_constcast(char*,s)
+#  define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b)
+#else
+#  define PNGZ_MSG_CAST(s) (s)
+#  define PNGZ_INPUT_CAST(b) (b)
+#endif
+
+/* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
+ * can handle at once.  This type need be no larger than 16 bits (so maximum of
+ * 65535), this define allows us to discover how big it is, but limited by the
+ * maximum for size_t.  The value can be overridden in a library build
+ * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
+ * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
+ * and may even improve performance on some systems (and degrade it on others.)
+ */
+#ifndef ZLIB_IO_MAX
+#  define ZLIB_IO_MAX ((uInt)-1)
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+/* The type of a compression buffer list used by the write code. */
+typedef struct png_compression_buffer
+{
+   struct png_compression_buffer *next;
+   png_byte                       output[1]; /* actually zbuf_size */
+} png_compression_buffer, *png_compression_bufferp;
+
+#define PNG_COMPRESSION_BUFFER_SIZE(pp)\
+   (offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)
+#endif
+
+/* Colorspace support; structures used in png_struct, png_info and in internal
+ * functions to hold and communicate information about the color space.
+ *
+ * PNG_COLORSPACE_SUPPORTED is only required if the application will perform
+ * colorspace corrections, otherwise all the colorspace information can be
+ * skipped and the size of libpng can be reduced (significantly) by compiling
+ * out the colorspace support.
+ */
+#ifdef PNG_COLORSPACE_SUPPORTED
+/* The chromaticities of the red, green and blue colorants and the chromaticity
+ * of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)).
+ */
+typedef struct png_xy
+{
+   png_fixed_point redx, redy;
+   png_fixed_point greenx, greeny;
+   png_fixed_point bluex, bluey;
+   png_fixed_point whitex, whitey;
+} png_xy;
+
+/* The same data as above but encoded as CIE XYZ values.  When this data comes
+ * from chromaticities the sum of the Y values is assumed to be 1.0
+ */
+typedef struct png_XYZ
+{
+   png_fixed_point red_X, red_Y, red_Z;
+   png_fixed_point green_X, green_Y, green_Z;
+   png_fixed_point blue_X, blue_Y, blue_Z;
+} png_XYZ;
+#endif /* COLORSPACE */
+
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+/* A colorspace is all the above plus, potentially, profile information;
+ * however at present libpng does not use the profile internally so it is only
+ * stored in the png_info struct (if iCCP is supported.)  The rendering intent
+ * is retained here and is checked.
+ *
+ * The file gamma encoding information is also stored here and gamma correction
+ * is done by libpng, whereas color correction must currently be done by the
+ * application.
+ */
+typedef struct png_colorspace
+{
+#ifdef PNG_GAMMA_SUPPORTED
+   png_fixed_point gamma;        /* File gamma */
+#endif
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+   png_xy      end_points_xy;    /* End points as chromaticities */
+   png_XYZ     end_points_XYZ;   /* End points as CIE XYZ colorant values */
+   png_uint_16 rendering_intent; /* Rendering intent of a profile */
+#endif
+
+   /* Flags are always defined to simplify the code. */
+   png_uint_16 flags;            /* As defined below */
+} png_colorspace, * PNG_RESTRICT png_colorspacerp;
+
+typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
+
+/* General flags for the 'flags' field */
+#define PNG_COLORSPACE_HAVE_GAMMA           0x0001
+#define PNG_COLORSPACE_HAVE_ENDPOINTS       0x0002
+#define PNG_COLORSPACE_HAVE_INTENT          0x0004
+#define PNG_COLORSPACE_FROM_gAMA            0x0008
+#define PNG_COLORSPACE_FROM_cHRM            0x0010
+#define PNG_COLORSPACE_FROM_sRGB            0x0020
+#define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
+#define PNG_COLORSPACE_MATCHES_sRGB         0x0080 /* exact match on profile */
+#define PNG_COLORSPACE_INVALID              0x8000
+#define PNG_COLORSPACE_CANCEL(flags)        (0xffff ^ (flags))
+#endif /* COLORSPACE || GAMMA */
+
+struct png_struct_def
+{
+#ifdef PNG_SETJMP_SUPPORTED
+   jmp_buf jmp_buf_local;     /* New name in 1.6.0 for jmp_buf in png_struct */
+   png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
+   jmp_buf *jmp_buf_ptr;      /* passed to longjmp_fn */
+   size_t jmp_buf_size;       /* size of the above, if allocated */
+#endif
+   png_error_ptr error_fn;    /* function for printing errors and aborting */
+#ifdef PNG_WARNINGS_SUPPORTED
+   png_error_ptr warning_fn;  /* function for printing warnings */
+#endif
+   png_voidp error_ptr;       /* user supplied struct for error functions */
+   png_rw_ptr write_data_fn;  /* function for writing output data */
+   png_rw_ptr read_data_fn;   /* function for reading input data */
+   png_voidp io_ptr;          /* ptr to application struct for I/O functions */
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   png_user_transform_ptr read_user_transform_fn; /* user read transform */
+#endif
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+   png_user_transform_ptr write_user_transform_fn; /* user write transform */
+#endif
+
+/* These were added in libpng-1.0.2 */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+   png_voidp user_transform_ptr; /* user supplied struct for user transform */
+   png_byte user_transform_depth;    /* bit depth of user transformed pixels */
+   png_byte user_transform_channels; /* channels in user transformed pixels */
+#endif
+#endif
+
+   png_uint_32 mode;          /* tells us where we are in the PNG file */
+   png_uint_32 flags;         /* flags indicating various things to libpng */
+   png_uint_32 transformations; /* which transformations to perform */
+
+   png_uint_32 zowner;        /* ID (chunk type) of zstream owner, 0 if none */
+   z_stream    zstream;       /* decompression structure */
+
+#ifdef PNG_WRITE_SUPPORTED
+   png_compression_bufferp zbuffer_list; /* Created on demand during write */
+   uInt                    zbuffer_size; /* size of the actual buffer */
+
+   int zlib_level;            /* holds zlib compression level */
+   int zlib_method;           /* holds zlib compression method */
+   int zlib_window_bits;      /* holds zlib compression window bits */
+   int zlib_mem_level;        /* holds zlib compression memory level */
+   int zlib_strategy;         /* holds zlib compression strategy */
+#endif
+/* Added at libpng 1.5.4 */
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+   int zlib_text_level;            /* holds zlib compression level */
+   int zlib_text_method;           /* holds zlib compression method */
+   int zlib_text_window_bits;      /* holds zlib compression window bits */
+   int zlib_text_mem_level;        /* holds zlib compression memory level */
+   int zlib_text_strategy;         /* holds zlib compression strategy */
+#endif
+/* End of material added at libpng 1.5.4 */
+/* Added at libpng 1.6.0 */
+#ifdef PNG_WRITE_SUPPORTED
+   int zlib_set_level;        /* Actual values set into the zstream on write */
+   int zlib_set_method;
+   int zlib_set_window_bits;
+   int zlib_set_mem_level;
+   int zlib_set_strategy;
+#endif
+
+   png_uint_32 width;         /* width of image in pixels */
+   png_uint_32 height;        /* height of image in pixels */
+   png_uint_32 num_rows;      /* number of rows in current pass */
+   png_uint_32 usr_width;     /* width of row at start of write */
+   size_t rowbytes;           /* size of row in bytes */
+   png_uint_32 iwidth;        /* width of current interlaced row in pixels */
+   png_uint_32 row_number;    /* current row in interlace pass */
+   png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
+   png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
+                               * While reading this is a pointer into
+                               * big_prev_row; while writing it is separately
+                               * allocated if needed.
+                               */
+   png_bytep row_buf;         /* buffer to save current (unfiltered) row.
+                               * While reading, this is a pointer into
+                               * big_row_buf; while writing it is separately
+                               * allocated.
+                               */
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   png_bytep try_row;    /* buffer to save trial row when filtering */
+   png_bytep tst_row;    /* buffer to save best trial row when filtering */
+#endif
+   size_t info_rowbytes;      /* Added in 1.5.4: cache of updated row bytes */
+
+   png_uint_32 idat_size;     /* current IDAT size for read */
+   png_uint_32 crc;           /* current chunk CRC value */
+   png_colorp palette;        /* palette from the input file */
+   png_uint_16 num_palette;   /* number of color entries in palette */
+
+/* Added at libpng-1.5.10 */
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   int num_palette_max;       /* maximum palette index found in IDAT */
+#endif
+
+   png_uint_16 num_trans;     /* number of transparency values */
+   png_byte compression;      /* file compression type (always 0) */
+   png_byte filter;           /* file filter type (always 0) */
+   png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
+   png_byte pass;             /* current interlace pass (0 - 6) */
+   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ in png.h ) */
+   png_byte color_type;       /* color type of file */
+   png_byte bit_depth;        /* bit depth of file */
+   png_byte usr_bit_depth;    /* bit depth of users row: write only */
+   png_byte pixel_depth;      /* number of bits per pixel */
+   png_byte channels;         /* number of channels in file */
+#ifdef PNG_WRITE_SUPPORTED
+   png_byte usr_channels;     /* channels at start of write: write only */
+#endif
+   png_byte sig_bytes;        /* magic bytes read/written from start of file */
+   png_byte maximum_pixel_depth;
+                              /* pixel depth used for the row buffers */
+   png_byte transformed_pixel_depth;
+                              /* pixel depth after read/write transforms */
+#if ZLIB_VERNUM >= 0x1240
+   png_byte zstream_start;    /* at start of an input zlib stream */
+#endif /* Zlib >= 1.2.4 */
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+   png_uint_16 filler;           /* filler bytes for pixel expansion */
+#endif
+
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+   png_byte background_gamma_type;
+   png_fixed_point background_gamma;
+   png_color_16 background;   /* background color in screen gamma space */
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   png_color_16 background_1; /* background normalized to gamma 1.0 */
+#endif
+#endif /* bKGD */
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+   png_flush_ptr output_flush_fn; /* Function for flushing output */
+   png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
+   png_uint_32 flush_rows;    /* number of rows written since last flush */
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
+   png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
+
+   png_bytep gamma_table;     /* gamma table for 8-bit depth files */
+   png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+   png_bytep gamma_from_1;    /* converts from 1.0 to screen */
+   png_bytep gamma_to_1;      /* converts from file to 1.0 */
+   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
+   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
+   png_color_8 sig_bit;       /* significant bits in each available channel */
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+   png_color_8 shift;         /* shift for significant bit transformation */
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
+ || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_bytep trans_alpha;           /* alpha values for paletted files */
+   png_color_16 trans_color;  /* transparent color for non-paletted files */
+#endif
+
+   png_read_status_ptr read_row_fn;   /* called after each row is decoded */
+   png_write_status_ptr write_row_fn; /* called after each row is encoded */
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+   png_progressive_info_ptr info_fn; /* called after header data fully read */
+   png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
+   png_progressive_end_ptr end_fn;   /* called after image is complete */
+   png_bytep save_buffer_ptr;        /* current location in save_buffer */
+   png_bytep save_buffer;            /* buffer for previously read data */
+   png_bytep current_buffer_ptr;     /* current location in current_buffer */
+   png_bytep current_buffer;         /* buffer for recently used data */
+   png_uint_32 push_length;          /* size of current input chunk */
+   png_uint_32 skip_length;          /* bytes to skip in input data */
+   size_t save_buffer_size;          /* amount of data now in save_buffer */
+   size_t save_buffer_max;           /* total size of save_buffer */
+   size_t buffer_size;               /* total amount of available input data */
+   size_t current_buffer_size;       /* amount of data now in current_buffer */
+   int process_mode;                 /* what push library is currently doing */
+   int cur_palette;                  /* current push library palette index */
+
+#endif /* PROGRESSIVE_READ */
+
+#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
+/* For the Borland special 64K segment handler */
+   png_bytepp offset_table_ptr;
+   png_bytep offset_table;
+   png_uint_16 offset_table_number;
+   png_uint_16 offset_table_count;
+   png_uint_16 offset_table_count_free;
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   png_bytep palette_lookup; /* lookup table for quantizing */
+   png_bytep quantize_index; /* index translation for palette files */
+#endif
+
+/* Options */
+#ifdef PNG_SET_OPTION_SUPPORTED
+   png_uint_32 options;           /* On/off state (up to 16 options) */
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng-1.7 */
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+   char time_buffer[29]; /* String to hold RFC 1123 time text */
+#endif
+#endif
+
+/* New members added in libpng-1.0.6 */
+
+   png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+   png_voidp user_chunk_ptr;
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
+#endif
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   int          unknown_default; /* As PNG_HANDLE_* */
+   unsigned int num_chunk_list;  /* Number of entries in the list */
+   png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
+                                  * followed by a PNG_HANDLE_* byte */
+#endif
+
+/* New members added in libpng-1.0.3 */
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   png_byte rgb_to_gray_status;
+   /* Added in libpng 1.5.5 to record setting of coefficients: */
+   png_byte rgb_to_gray_coefficients_set;
+   /* These were changed from png_byte in libpng-1.0.6 */
+   png_uint_16 rgb_to_gray_red_coeff;
+   png_uint_16 rgb_to_gray_green_coeff;
+   /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
+#endif
+
+/* New member added in libpng-1.6.36 */
+#if defined(PNG_READ_EXPAND_SUPPORTED) && \
+    defined(PNG_ARM_NEON_IMPLEMENTATION)
+   png_bytep riffled_palette; /* buffer for accelerated palette expansion */
+#endif
+
+/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+/* Changed from png_byte to png_uint_32 at version 1.2.0 */
+   png_uint_32 mng_features_permitted;
+#endif
+
+/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   png_byte filter_type;
+#endif
+
+/* New members added in libpng-1.2.0 */
+
+/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_voidp mem_ptr;             /* user supplied struct for mem functions */
+   png_malloc_ptr malloc_fn;      /* function for allocating memory */
+   png_free_ptr free_fn;          /* function for freeing memory */
+#endif
+
+/* New member added in libpng-1.0.13 and 1.2.0 */
+   png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* The following three members were added at version 1.0.14 and 1.2.4 */
+   png_bytep quantize_sort;          /* working sort array */
+   png_bytep index_to_palette;       /* where the original index currently is
+                                        in the palette */
+   png_bytep palette_to_index;       /* which original index points to this
+                                         palette color */
+#endif
+
+/* New members added in libpng-1.0.16 and 1.2.6 */
+   png_byte compression_type;
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   png_uint_32 user_width_max;
+   png_uint_32 user_height_max;
+
+   /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
+    * chunks that can be stored (0 means unlimited).
+    */
+   png_uint_32 user_chunk_cache_max;
+
+   /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
+    * can occupy when decompressed.  0 means unlimited.
+    */
+   png_alloc_size_t user_chunk_malloc_max;
+#endif
+
+/* New member added in libpng-1.0.25 and 1.2.17 */
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+   /* Temporary storage for unknown chunk that the library doesn't recognize,
+    * used while reading the chunk.
+    */
+   png_unknown_chunk unknown_chunk;
+#endif
+
+/* New member added in libpng-1.2.26 */
+   size_t old_big_row_buf_size;
+
+#ifdef PNG_READ_SUPPORTED
+/* New member added in libpng-1.2.30 */
+  png_bytep        read_buffer;      /* buffer for reading chunk data */
+  png_alloc_size_t read_buffer_size; /* current size of the buffer */
+#endif
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+  uInt             IDAT_read_size;   /* limit on read buffer size for IDAT */
+#endif
+
+#ifdef PNG_IO_STATE_SUPPORTED
+/* New member added in libpng-1.4.0 */
+   png_uint_32 io_state;
+#endif
+
+/* New member added in libpng-1.5.6 */
+   png_bytep big_prev_row;
+
+/* New member added in libpng-1.5.7 */
+   void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
+      png_bytep row, png_const_bytep prev_row);
+
+#ifdef PNG_READ_SUPPORTED
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+   png_colorspace   colorspace;
+#endif
+#endif
+};
+#endif /* PNGSTRUCT_H */
diff --git a/extern/libpng/pngtest.c b/extern/libpng/pngtest.c
new file mode 100644
index 0000000000..a715ae1123
--- /dev/null
+++ b/extern/libpng/pngtest.c
@@ -0,0 +1,2158 @@
+
+/* pngtest.c - a simple test program to test libpng
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This program reads in a PNG image, writes it out again, and then
+ * compares the two files.  If the files are identical, this shows that
+ * the basic chunk handling, filtering, and (de)compression code is working
+ * properly.  It does not currently test all of the transforms, although
+ * it probably should.
+ *
+ * The program will report "FAIL" in certain legitimate cases:
+ * 1) when the compression level or filter selection method is changed.
+ * 2) when the maximum IDAT size (PNG_ZBUF_SIZE in pngconf.h) is not 8192.
+ * 3) unknown unsafe-to-copy ancillary chunks or unknown critical chunks
+ *    exist in the input file.
+ * 4) others not listed here...
+ * In these cases, it is best to check with another tool such as "pngcheck"
+ * to see what the differences between the two files are.
+ *
+ * If a filename is given on the command-line, then this file is used
+ * for the input, rather than the default "pngtest.png".  This allows
+ * testing a wide variety of files easily.  You can also test a number
+ * of files at once by typing "pngtest -m file1.png file2.png ..."
+ */
+
+#define _POSIX_SOURCE 1
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* Defined so I can write to a file on gui/windowing platforms */
+/*  #define STDERR stderr  */
+#define STDERR stdout   /* For DOS */
+
+#include "png.h"
+
+/* Known chunks that exist in pngtest.png must be supported or pngtest will fail
+ * simply as a result of re-ordering them.  This may be fixed in 1.7
+ *
+ * pngtest allocates a single row buffer for each row and overwrites it,
+ * therefore if the write side doesn't support the writing of interlaced images
+ * nothing can be done for an interlaced image (and the code below will fail
+ * horribly trying to write extra data after writing garbage).
+ */
+#if defined PNG_READ_SUPPORTED && /* else nothing can be done */\
+   defined PNG_READ_bKGD_SUPPORTED &&\
+   defined PNG_READ_cHRM_SUPPORTED &&\
+   defined PNG_READ_gAMA_SUPPORTED &&\
+   defined PNG_READ_oFFs_SUPPORTED &&\
+   defined PNG_READ_pCAL_SUPPORTED &&\
+   defined PNG_READ_pHYs_SUPPORTED &&\
+   defined PNG_READ_sBIT_SUPPORTED &&\
+   defined PNG_READ_sCAL_SUPPORTED &&\
+   defined PNG_READ_sRGB_SUPPORTED &&\
+   defined PNG_READ_sPLT_SUPPORTED &&\
+   defined PNG_READ_tEXt_SUPPORTED &&\
+   defined PNG_READ_tIME_SUPPORTED &&\
+   defined PNG_READ_zTXt_SUPPORTED &&\
+   (defined PNG_WRITE_INTERLACING_SUPPORTED || PNG_LIBPNG_VER >= 10700)
+
+#ifdef PNG_ZLIB_HEADER
+#  include PNG_ZLIB_HEADER /* defined by pnglibconf.h from 1.7 */
+#else
+#  include "zlib.h"
+#endif
+
+/* Copied from pngpriv.h but only used in error messages below. */
+#ifndef PNG_ZBUF_SIZE
+#  define PNG_ZBUF_SIZE 8192
+#endif
+#define FCLOSE(file) fclose(file)
+
+#ifndef PNG_STDIO_SUPPORTED
+typedef FILE                * png_FILE_p;
+#endif
+
+/* Makes pngtest verbose so we can find problems. */
+#ifndef PNG_DEBUG
+#  define PNG_DEBUG 0
+#endif
+
+#if PNG_DEBUG > 1
+#  define pngtest_debug(m)        ((void)fprintf(stderr, m "\n"))
+#  define pngtest_debug1(m,p1)    ((void)fprintf(stderr, m "\n", p1))
+#  define pngtest_debug2(m,p1,p2) ((void)fprintf(stderr, m "\n", p1, p2))
+#else
+#  define pngtest_debug(m)        ((void)0)
+#  define pngtest_debug1(m,p1)    ((void)0)
+#  define pngtest_debug2(m,p1,p2) ((void)0)
+#endif
+
+#if !PNG_DEBUG
+#  define SINGLE_ROWBUF_ALLOC  /* Makes buffer overruns easier to nail */
+#endif
+
+#ifndef PNG_UNUSED
+#  define PNG_UNUSED(param) (void)param;
+#endif
+
+/* Turn on CPU timing
+#define PNGTEST_TIMING
+*/
+
+#ifndef PNG_FLOATING_POINT_SUPPORTED
+#undef PNGTEST_TIMING
+#endif
+
+#ifdef PNGTEST_TIMING
+static float t_start, t_stop, t_decode, t_encode, t_misc;
+#include <time.h>
+#endif
+
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+#define PNG_tIME_STRING_LENGTH 29
+static int tIME_chunk_present = 0;
+static char tIME_string[PNG_tIME_STRING_LENGTH] = "tIME chunk is not present";
+
+#if PNG_LIBPNG_VER < 10619
+#define png_convert_to_rfc1123_buffer(ts, t) tIME_to_str(read_ptr, ts, t)
+
+static int
+tIME_to_str(png_structp png_ptr, png_charp ts, png_const_timep t)
+{
+   png_const_charp str = png_convert_to_rfc1123(png_ptr, t);
+
+   if (str == NULL)
+       return 0;
+
+   strcpy(ts, str);
+   return 1;
+}
+#endif /* older libpng */
+#endif
+
+static int verbose = 0;
+static int strict = 0;
+static int relaxed = 0;
+static int xfail = 0;
+static int unsupported_chunks = 0; /* chunk unsupported by libpng in input */
+static int error_count = 0; /* count calls to png_error */
+static int warning_count = 0; /* count calls to png_warning */
+
+/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr) png_ptr->jmpbuf
+#endif
+
+/* Defines for unknown chunk handling if required. */
+#ifndef PNG_HANDLE_CHUNK_ALWAYS
+#  define PNG_HANDLE_CHUNK_ALWAYS       3
+#endif
+#ifndef PNG_HANDLE_CHUNK_IF_SAFE
+#  define PNG_HANDLE_CHUNK_IF_SAFE      2
+#endif
+
+/* Utility to save typing/errors, the argument must be a name */
+#define MEMZERO(var) ((void)memset(&var, 0, sizeof var))
+
+/* Example of using row callbacks to make a simple progress meter */
+static int status_pass = 1;
+static int status_dots_requested = 0;
+static int status_dots = 1;
+
+static void PNGCBAPI
+read_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
+{
+   if (png_ptr == NULL || row_number > PNG_UINT_31_MAX)
+      return;
+
+   if (status_pass != pass)
+   {
+      fprintf(stdout, "\n Pass %d: ", pass);
+      status_pass = pass;
+      status_dots = 31;
+   }
+
+   status_dots--;
+
+   if (status_dots == 0)
+   {
+      fprintf(stdout, "\n         ");
+      status_dots=30;
+   }
+
+   fprintf(stdout, "r");
+}
+
+#ifdef PNG_WRITE_SUPPORTED
+static void PNGCBAPI
+write_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
+{
+   if (png_ptr == NULL || row_number > PNG_UINT_31_MAX || pass > 7)
+      return;
+
+   fprintf(stdout, "w");
+}
+#endif
+
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+/* Example of using a user transform callback (doesn't do anything at present).
+ */
+static void PNGCBAPI
+read_user_callback(png_structp png_ptr, png_row_infop row_info, png_bytep data)
+{
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(row_info)
+   PNG_UNUSED(data)
+}
+#endif
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+/* Example of using user transform callback (we don't transform anything,
+ * but merely count the zero samples)
+ */
+
+static png_uint_32 zero_samples;
+
+static void PNGCBAPI
+count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
+{
+   png_bytep dp = data;
+   if (png_ptr == NULL)
+      return;
+
+   /* Contents of row_info:
+    *  png_uint_32 width      width of row
+    *  png_uint_32 rowbytes   number of bytes in row
+    *  png_byte color_type    color type of pixels
+    *  png_byte bit_depth     bit depth of samples
+    *  png_byte channels      number of channels (1-4)
+    *  png_byte pixel_depth   bits per pixel (depth*channels)
+    */
+
+   /* Counts the number of zero samples (or zero pixels if color_type is 3 */
+
+   if (row_info->color_type == 0 || row_info->color_type == 3)
+   {
+      int pos = 0;
+      png_uint_32 n, nstop;
+
+      for (n = 0, nstop=row_info->width; n<nstop; n++)
+      {
+         if (row_info->bit_depth == 1)
+         {
+            if (((*dp << pos++ ) & 0x80) == 0)
+               zero_samples++;
+
+            if (pos == 8)
+            {
+               pos = 0;
+               dp++;
+            }
+         }
+
+         if (row_info->bit_depth == 2)
+         {
+            if (((*dp << (pos+=2)) & 0xc0) == 0)
+               zero_samples++;
+
+            if (pos == 8)
+            {
+               pos = 0;
+               dp++;
+            }
+         }
+
+         if (row_info->bit_depth == 4)
+         {
+            if (((*dp << (pos+=4)) & 0xf0) == 0)
+               zero_samples++;
+
+            if (pos == 8)
+            {
+               pos = 0;
+               dp++;
+            }
+         }
+
+         if (row_info->bit_depth == 8)
+            if (*dp++ == 0)
+               zero_samples++;
+
+         if (row_info->bit_depth == 16)
+         {
+            if ((*dp | *(dp+1)) == 0)
+               zero_samples++;
+            dp+=2;
+         }
+      }
+   }
+   else /* Other color types */
+   {
+      png_uint_32 n, nstop;
+      int channel;
+      int color_channels = row_info->channels;
+      if (row_info->color_type > 3)
+         color_channels--;
+
+      for (n = 0, nstop=row_info->width; n<nstop; n++)
+      {
+         for (channel = 0; channel < color_channels; channel++)
+         {
+            if (row_info->bit_depth == 8)
+               if (*dp++ == 0)
+                  zero_samples++;
+
+            if (row_info->bit_depth == 16)
+            {
+               if ((*dp | *(dp+1)) == 0)
+                  zero_samples++;
+
+               dp+=2;
+            }
+         }
+         if (row_info->color_type > 3)
+         {
+            dp++;
+            if (row_info->bit_depth == 16)
+               dp++;
+         }
+      }
+   }
+}
+#endif /* WRITE_USER_TRANSFORM */
+
+#ifndef PNG_STDIO_SUPPORTED
+/* START of code to validate stdio-free compilation */
+/* These copies of the default read/write functions come from pngrio.c and
+ * pngwio.c.  They allow "don't include stdio" testing of the library.
+ * This is the function that does the actual reading of data.  If you are
+ * not reading from a standard C stream, you should create a replacement
+ * read_data function and use it at run time with png_set_read_fn(), rather
+ * than changing the library.
+ */
+
+#ifdef PNG_IO_STATE_SUPPORTED
+void
+pngtest_check_io_state(png_structp png_ptr, size_t data_length,
+    png_uint_32 io_op);
+void
+pngtest_check_io_state(png_structp png_ptr, size_t data_length,
+    png_uint_32 io_op)
+{
+   png_uint_32 io_state = png_get_io_state(png_ptr);
+   int err = 0;
+
+   /* Check if the current operation (reading / writing) is as expected. */
+   if ((io_state & PNG_IO_MASK_OP) != io_op)
+      png_error(png_ptr, "Incorrect operation in I/O state");
+
+   /* Check if the buffer size specific to the current location
+    * (file signature / header / data / crc) is as expected.
+    */
+   switch (io_state & PNG_IO_MASK_LOC)
+   {
+   case PNG_IO_SIGNATURE:
+      if (data_length > 8)
+         err = 1;
+      break;
+   case PNG_IO_CHUNK_HDR:
+      if (data_length != 8)
+         err = 1;
+      break;
+   case PNG_IO_CHUNK_DATA:
+      break;  /* no restrictions here */
+   case PNG_IO_CHUNK_CRC:
+      if (data_length != 4)
+         err = 1;
+      break;
+   default:
+      err = 1;  /* uninitialized */
+   }
+   if (err != 0)
+      png_error(png_ptr, "Bad I/O state or buffer size");
+}
+#endif
+
+static void PNGCBAPI
+pngtest_read_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check = 0;
+   png_voidp io_ptr;
+
+   /* fread() returns 0 on error, so it is OK to store this in a size_t
+    * instead of an int, which is what fread() actually returns.
+    */
+   io_ptr = png_get_io_ptr(png_ptr);
+   if (io_ptr != NULL)
+   {
+      check = fread(data, 1, length, (png_FILE_p)io_ptr);
+   }
+
+   if (check != length)
+   {
+      png_error(png_ptr, "Read Error");
+   }
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   pngtest_check_io_state(png_ptr, length, PNG_IO_READING);
+#endif
+}
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+static void PNGCBAPI
+pngtest_flush(png_structp png_ptr)
+{
+   /* Do nothing; fflush() is said to be just a waste of energy. */
+   PNG_UNUSED(png_ptr)   /* Stifle compiler warning */
+}
+#endif
+
+/* This is the function that does the actual writing of data.  If you are
+ * not writing to a standard C stream, you should create a replacement
+ * write_data function and use it at run time with png_set_write_fn(), rather
+ * than changing the library.
+ */
+static void PNGCBAPI
+pngtest_write_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check;
+
+   check = fwrite(data, 1, length, (png_FILE_p)png_get_io_ptr(png_ptr));
+
+   if (check != length)
+   {
+      png_error(png_ptr, "Write Error");
+   }
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   pngtest_check_io_state(png_ptr, length, PNG_IO_WRITING);
+#endif
+}
+#endif /* !STDIO */
+
+/* This function is called when there is a warning, but the library thinks
+ * it can continue anyway.  Replacement functions don't have to do anything
+ * here if you don't want to.  In the default configuration, png_ptr is
+ * not used, but it is passed in case it may be useful.
+ */
+typedef struct
+{
+   const char *file_name;
+}  pngtest_error_parameters;
+
+static void PNGCBAPI
+pngtest_warning(png_structp png_ptr, png_const_charp message)
+{
+   const char *name = "UNKNOWN (ERROR!)";
+   pngtest_error_parameters *test =
+      (pngtest_error_parameters*)png_get_error_ptr(png_ptr);
+
+   ++warning_count;
+
+   if (test != NULL && test->file_name != NULL)
+      name = test->file_name;
+
+   fprintf(STDERR, "\n%s: libpng warning: %s\n", name, message);
+}
+
+/* This is the default error handling function.  Note that replacements for
+ * this function MUST NOT RETURN, or the program will likely crash.  This
+ * function is used by default, or if the program supplies NULL for the
+ * error function pointer in png_set_error_fn().
+ */
+static void PNGCBAPI
+pngtest_error(png_structp png_ptr, png_const_charp message)
+{
+   ++error_count;
+
+   pngtest_warning(png_ptr, message);
+   /* We can return because png_error calls the default handler, which is
+    * actually OK in this case.
+    */
+}
+
+/* END of code to validate stdio-free compilation */
+
+/* START of code to validate memory allocation and deallocation */
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+
+/* Allocate memory.  For reasonable files, size should never exceed
+ * 64K.  However, zlib may allocate more than 64K if you don't tell
+ * it not to.  See zconf.h and png.h for more information.  zlib does
+ * need to allocate exactly 64K, so whatever you call here must
+ * have the ability to do that.
+ *
+ * This piece of code can be compiled to validate max 64K allocations
+ * by setting MAXSEG_64K in zlib zconf.h *or* PNG_MAX_MALLOC_64K.
+ */
+typedef struct memory_information
+{
+   png_alloc_size_t          size;
+   png_voidp                 pointer;
+   struct memory_information *next;
+} memory_information;
+typedef memory_information *memory_infop;
+
+static memory_infop pinformation = NULL;
+static int current_allocation = 0;
+static int maximum_allocation = 0;
+static int total_allocation = 0;
+static int num_allocations = 0;
+
+png_voidp PNGCBAPI png_debug_malloc PNGARG((png_structp png_ptr,
+    png_alloc_size_t size));
+void PNGCBAPI png_debug_free PNGARG((png_structp png_ptr, png_voidp ptr));
+
+png_voidp
+PNGCBAPI png_debug_malloc(png_structp png_ptr, png_alloc_size_t size)
+{
+
+   /* png_malloc has already tested for NULL; png_create_struct calls
+    * png_debug_malloc directly, with png_ptr == NULL which is OK
+    */
+
+   if (size == 0)
+      return (NULL);
+
+   /* This calls the library allocator twice, once to get the requested
+      buffer and once to get a new free list entry. */
+   {
+      /* Disable malloc_fn and free_fn */
+      memory_infop pinfo;
+      png_set_mem_fn(png_ptr, NULL, NULL, NULL);
+      pinfo = (memory_infop)png_malloc(png_ptr,
+          (sizeof *pinfo));
+      pinfo->size = size;
+      current_allocation += size;
+      total_allocation += size;
+      num_allocations ++;
+
+      if (current_allocation > maximum_allocation)
+         maximum_allocation = current_allocation;
+
+      pinfo->pointer = png_malloc(png_ptr, size);
+      /* Restore malloc_fn and free_fn */
+
+      png_set_mem_fn(png_ptr,
+          NULL, png_debug_malloc, png_debug_free);
+
+      if (size != 0 && pinfo->pointer == NULL)
+      {
+         current_allocation -= size;
+         total_allocation -= size;
+         png_error(png_ptr,
+           "out of memory in pngtest->png_debug_malloc");
+      }
+
+      pinfo->next = pinformation;
+      pinformation = pinfo;
+      /* Make sure the caller isn't assuming zeroed memory. */
+      memset(pinfo->pointer, 0xdd, pinfo->size);
+
+      if (verbose != 0)
+         printf("png_malloc %lu bytes at %p\n", (unsigned long)size,
+             pinfo->pointer);
+
+      return (png_voidp)(pinfo->pointer);
+   }
+}
+
+/* Free a pointer.  It is removed from the list at the same time. */
+void PNGCBAPI
+png_debug_free(png_structp png_ptr, png_voidp ptr)
+{
+   if (png_ptr == NULL)
+      fprintf(STDERR, "NULL pointer to png_debug_free.\n");
+
+   if (ptr == 0)
+   {
+#if 0 /* This happens all the time. */
+      fprintf(STDERR, "WARNING: freeing NULL pointer\n");
+#endif
+      return;
+   }
+
+   /* Unlink the element from the list. */
+   if (pinformation != NULL)
+   {
+      memory_infop *ppinfo = &pinformation;
+
+      for (;;)
+      {
+         memory_infop pinfo = *ppinfo;
+
+         if (pinfo->pointer == ptr)
+         {
+            *ppinfo = pinfo->next;
+            current_allocation -= pinfo->size;
+            if (current_allocation < 0)
+               fprintf(STDERR, "Duplicate free of memory\n");
+            /* We must free the list element too, but first kill
+               the memory that is to be freed. */
+            memset(ptr, 0x55, pinfo->size);
+            free(pinfo);
+            pinfo = NULL;
+            break;
+         }
+
+         if (pinfo->next == NULL)
+         {
+            fprintf(STDERR, "Pointer %p not found\n", ptr);
+            break;
+         }
+
+         ppinfo = &pinfo->next;
+      }
+   }
+
+   /* Finally free the data. */
+   if (verbose != 0)
+      printf("Freeing %p\n", ptr);
+
+   if (ptr != NULL)
+      free(ptr);
+   ptr = NULL;
+}
+#endif /* USER_MEM && DEBUG */
+/* END of code to test memory allocation/deallocation */
+
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+/* Demonstration of user chunk support of the sTER and vpAg chunks */
+
+/* (sTER is a public chunk not yet known by libpng.  vpAg is a private
+chunk used in ImageMagick to store "virtual page" size).  */
+
+static struct user_chunk_data
+{
+   png_const_infop info_ptr;
+   png_uint_32     vpAg_width, vpAg_height;
+   png_byte        vpAg_units;
+   png_byte        sTER_mode;
+   int             location[2];
+}
+user_chunk_data;
+
+/* Used for location and order; zero means nothing. */
+#define have_sTER   0x01
+#define have_vpAg   0x02
+#define before_PLTE 0x10
+#define before_IDAT 0x20
+#define after_IDAT  0x40
+
+static void
+init_callback_info(png_const_infop info_ptr)
+{
+   MEMZERO(user_chunk_data);
+   user_chunk_data.info_ptr = info_ptr;
+}
+
+static int
+set_location(png_structp png_ptr, struct user_chunk_data *data, int what)
+{
+   int location;
+
+   if ((data->location[0] & what) != 0 || (data->location[1] & what) != 0)
+      return 0; /* already have one of these */
+
+   /* Find where we are (the code below zeroes info_ptr to indicate that the
+    * chunks before the first IDAT have been read.)
+    */
+   if (data->info_ptr == NULL) /* after IDAT */
+      location = what | after_IDAT;
+
+   else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE) != 0)
+      location = what | before_IDAT;
+
+   else
+      location = what | before_PLTE;
+
+   if (data->location[0] == 0)
+      data->location[0] = location;
+
+   else
+      data->location[1] = location;
+
+   return 1; /* handled */
+}
+
+static int PNGCBAPI
+read_user_chunk_callback(png_struct *png_ptr, png_unknown_chunkp chunk)
+{
+   struct user_chunk_data *my_user_chunk_data =
+      (struct user_chunk_data*)png_get_user_chunk_ptr(png_ptr);
+
+   if (my_user_chunk_data == NULL)
+      png_error(png_ptr, "lost user chunk pointer");
+
+   /* Return one of the following:
+    *    return (-n);  chunk had an error
+    *    return (0);  did not recognize
+    *    return (n);  success
+    *
+    * The unknown chunk structure contains the chunk data:
+    * png_byte name[5];
+    * png_byte *data;
+    * size_t size;
+    *
+    * Note that libpng has already taken care of the CRC handling.
+    */
+
+   if (chunk->name[0] == 115 && chunk->name[1] ==  84 &&     /* s  T */
+       chunk->name[2] ==  69 && chunk->name[3] ==  82)       /* E  R */
+      {
+         /* Found sTER chunk */
+         if (chunk->size != 1)
+            return (-1); /* Error return */
+
+         if (chunk->data[0] != 0 && chunk->data[0] != 1)
+            return (-1);  /* Invalid mode */
+
+         if (set_location(png_ptr, my_user_chunk_data, have_sTER) != 0)
+         {
+            my_user_chunk_data->sTER_mode=chunk->data[0];
+            return (1);
+         }
+
+         else
+            return (0); /* duplicate sTER - give it to libpng */
+      }
+
+   if (chunk->name[0] != 118 || chunk->name[1] != 112 ||    /* v  p */
+       chunk->name[2] !=  65 || chunk->name[3] != 103)      /* A  g */
+      return (0); /* Did not recognize */
+
+   /* Found ImageMagick vpAg chunk */
+
+   if (chunk->size != 9)
+      return (-1); /* Error return */
+
+   if (set_location(png_ptr, my_user_chunk_data, have_vpAg) == 0)
+      return (0);  /* duplicate vpAg */
+
+   my_user_chunk_data->vpAg_width = png_get_uint_31(png_ptr, chunk->data);
+   my_user_chunk_data->vpAg_height = png_get_uint_31(png_ptr, chunk->data + 4);
+   my_user_chunk_data->vpAg_units = chunk->data[8];
+
+   return (1);
+}
+
+#ifdef PNG_WRITE_SUPPORTED
+static void
+write_sTER_chunk(png_structp write_ptr)
+{
+   png_byte sTER[5] = {115,  84,  69,  82, '\0'};
+
+   if (verbose != 0)
+      fprintf(STDERR, "\n stereo mode = %d\n", user_chunk_data.sTER_mode);
+
+   png_write_chunk(write_ptr, sTER, &user_chunk_data.sTER_mode, 1);
+}
+
+static void
+write_vpAg_chunk(png_structp write_ptr)
+{
+   png_byte vpAg[5] = {118, 112,  65, 103, '\0'};
+
+   png_byte vpag_chunk_data[9];
+
+   if (verbose != 0)
+      fprintf(STDERR, " vpAg = %lu x %lu, units = %d\n",
+          (unsigned long)user_chunk_data.vpAg_width,
+          (unsigned long)user_chunk_data.vpAg_height,
+          user_chunk_data.vpAg_units);
+
+   png_save_uint_32(vpag_chunk_data, user_chunk_data.vpAg_width);
+   png_save_uint_32(vpag_chunk_data + 4, user_chunk_data.vpAg_height);
+   vpag_chunk_data[8] = user_chunk_data.vpAg_units;
+   png_write_chunk(write_ptr, vpAg, vpag_chunk_data, 9);
+}
+
+static void
+write_chunks(png_structp write_ptr, int location)
+{
+   int i;
+
+   /* Notice that this preserves the original chunk order, however chunks
+    * intercepted by the callback will be written *after* chunks passed to
+    * libpng.  This will actually reverse a pair of sTER chunks or a pair of
+    * vpAg chunks, resulting in an error later.  This is not worth worrying
+    * about - the chunks should not be duplicated!
+    */
+   for (i=0; i<2; ++i)
+   {
+      if (user_chunk_data.location[i] == (location | have_sTER))
+         write_sTER_chunk(write_ptr);
+
+      else if (user_chunk_data.location[i] == (location | have_vpAg))
+         write_vpAg_chunk(write_ptr);
+   }
+}
+#endif /* WRITE */
+#else /* !READ_USER_CHUNKS */
+#  define write_chunks(pp,loc) ((void)0)
+#endif
+/* END of code to demonstrate user chunk support */
+
+/* START of code to check that libpng has the required text support; this only
+ * checks for the write support because if read support is missing the chunk
+ * will simply not be reported back to pngtest.
+ */
+#ifdef PNG_TEXT_SUPPORTED
+static void
+pngtest_check_text_support(png_structp png_ptr, png_textp text_ptr,
+    int num_text)
+{
+   while (num_text > 0)
+   {
+      switch (text_ptr[--num_text].compression)
+      {
+         case PNG_TEXT_COMPRESSION_NONE:
+            break;
+
+         case PNG_TEXT_COMPRESSION_zTXt:
+#           ifndef PNG_WRITE_zTXt_SUPPORTED
+               ++unsupported_chunks;
+               /* In libpng 1.7 this now does an app-error, so stop it: */
+               text_ptr[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+#           endif
+            break;
+
+         case PNG_ITXT_COMPRESSION_NONE:
+         case PNG_ITXT_COMPRESSION_zTXt:
+#           ifndef PNG_WRITE_iTXt_SUPPORTED
+               ++unsupported_chunks;
+               text_ptr[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+#           endif
+            break;
+
+         default:
+            /* This is an error */
+            png_error(png_ptr, "invalid text chunk compression field");
+            break;
+      }
+   }
+}
+#endif
+/* END of code to check that libpng has the required text support */
+
+/* Test one file */
+static int
+test_one_file(const char *inname, const char *outname)
+{
+   static png_FILE_p fpin;
+   static png_FILE_p fpout;  /* "static" prevents setjmp corruption */
+   pngtest_error_parameters error_parameters;
+   png_structp read_ptr;
+   png_infop read_info_ptr, end_info_ptr;
+#ifdef PNG_WRITE_SUPPORTED
+   png_structp write_ptr;
+   png_infop write_info_ptr;
+   png_infop write_end_info_ptr;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   int interlace_preserved = 1;
+#endif /* WRITE_FILTER */
+#else /* !WRITE */
+   png_structp write_ptr = NULL;
+   png_infop write_info_ptr = NULL;
+   png_infop write_end_info_ptr = NULL;
+#endif /* !WRITE */
+   png_bytep row_buf;
+   png_uint_32 y;
+   png_uint_32 width, height;
+   volatile int num_passes;
+   int pass;
+   int bit_depth, color_type;
+
+   row_buf = NULL;
+   error_parameters.file_name = inname;
+
+   if ((fpin = fopen(inname, "rb")) == NULL)
+   {
+      fprintf(STDERR, "Could not find input file %s\n", inname);
+      return (1);
+   }
+
+   if ((fpout = fopen(outname, "wb")) == NULL)
+   {
+      fprintf(STDERR, "Could not open output file %s\n", outname);
+      FCLOSE(fpin);
+      return (1);
+   }
+
+   pngtest_debug("Allocating read and write structures");
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+   read_ptr =
+       png_create_read_struct_2(PNG_LIBPNG_VER_STRING, NULL,
+       NULL, NULL, NULL, png_debug_malloc, png_debug_free);
+#else
+   read_ptr =
+       png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+#endif
+   png_set_error_fn(read_ptr, &error_parameters, pngtest_error,
+       pngtest_warning);
+
+#ifdef PNG_WRITE_SUPPORTED
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+   write_ptr =
+       png_create_write_struct_2(PNG_LIBPNG_VER_STRING, NULL,
+       NULL, NULL, NULL, png_debug_malloc, png_debug_free);
+#else
+   write_ptr =
+       png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+#endif
+   png_set_error_fn(write_ptr, &error_parameters, pngtest_error,
+       pngtest_warning);
+#endif
+   pngtest_debug("Allocating read_info, write_info and end_info structures");
+   read_info_ptr = png_create_info_struct(read_ptr);
+   end_info_ptr = png_create_info_struct(read_ptr);
+#ifdef PNG_WRITE_SUPPORTED
+   write_info_ptr = png_create_info_struct(write_ptr);
+   write_end_info_ptr = png_create_info_struct(write_ptr);
+#endif
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   init_callback_info(read_info_ptr);
+   png_set_read_user_chunk_fn(read_ptr, &user_chunk_data,
+       read_user_chunk_callback);
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+   pngtest_debug("Setting jmpbuf for read struct");
+   if (setjmp(png_jmpbuf(read_ptr)))
+   {
+      fprintf(STDERR, "%s -> %s: libpng read error\n", inname, outname);
+      png_free(read_ptr, row_buf);
+      row_buf = NULL;
+      if (verbose != 0)
+        fprintf(STDERR, "   destroy read structs\n");
+      png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
+#ifdef PNG_WRITE_SUPPORTED
+      if (verbose != 0)
+        fprintf(STDERR, "   destroy write structs\n");
+      png_destroy_info_struct(write_ptr, &write_end_info_ptr);
+      png_destroy_write_struct(&write_ptr, &write_info_ptr);
+#endif
+      FCLOSE(fpin);
+      FCLOSE(fpout);
+      return (1);
+   }
+
+#ifdef PNG_WRITE_SUPPORTED
+   pngtest_debug("Setting jmpbuf for write struct");
+
+   if (setjmp(png_jmpbuf(write_ptr)))
+   {
+      fprintf(STDERR, "%s -> %s: libpng write error\n", inname, outname);
+      png_free(read_ptr, row_buf);
+      row_buf = NULL;
+      if (verbose != 0)
+        fprintf(STDERR, "   destroying read structs\n");
+      png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
+      if (verbose != 0)
+        fprintf(STDERR, "   destroying write structs\n");
+      png_destroy_info_struct(write_ptr, &write_end_info_ptr);
+      png_destroy_write_struct(&write_ptr, &write_info_ptr);
+      FCLOSE(fpin);
+      FCLOSE(fpout);
+      return (1);
+   }
+#endif
+#endif
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+   if (strict != 0)
+   {
+      /* Treat png_benign_error() as errors on read */
+      png_set_benign_errors(read_ptr, 0);
+
+# ifdef PNG_WRITE_SUPPORTED
+      /* Treat them as errors on write */
+      png_set_benign_errors(write_ptr, 0);
+# endif
+
+      /* if strict is not set, then app warnings and errors are treated as
+       * warnings in release builds, but not in unstable builds; this can be
+       * changed with '--relaxed'.
+       */
+   }
+
+   else if (relaxed != 0)
+   {
+      /* Allow application (pngtest) errors and warnings to pass */
+      png_set_benign_errors(read_ptr, 1);
+
+      /* Turn off CRC checking while reading */
+      png_set_crc_action(read_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
+
+#ifdef PNG_IGNORE_ADLER32
+      /* Turn off ADLER32 checking while reading */
+      png_set_option(read_ptr, PNG_IGNORE_ADLER32, PNG_OPTION_ON);
+#endif
+
+# ifdef PNG_WRITE_SUPPORTED
+      png_set_benign_errors(write_ptr, 1);
+# endif
+
+   }
+#endif /* BENIGN_ERRORS */
+
+   pngtest_debug("Initializing input and output streams");
+#ifdef PNG_STDIO_SUPPORTED
+   png_init_io(read_ptr, fpin);
+#  ifdef PNG_WRITE_SUPPORTED
+   png_init_io(write_ptr, fpout);
+#  endif
+#else
+   png_set_read_fn(read_ptr, (png_voidp)fpin, pngtest_read_data);
+#  ifdef PNG_WRITE_SUPPORTED
+   png_set_write_fn(write_ptr, (png_voidp)fpout,  pngtest_write_data,
+#    ifdef PNG_WRITE_FLUSH_SUPPORTED
+       pngtest_flush);
+#    else
+       NULL);
+#    endif
+#  endif
+#endif
+
+   if (status_dots_requested == 1)
+   {
+#ifdef PNG_WRITE_SUPPORTED
+      png_set_write_status_fn(write_ptr, write_row_callback);
+#endif
+      png_set_read_status_fn(read_ptr, read_row_callback);
+   }
+
+   else
+   {
+#ifdef PNG_WRITE_SUPPORTED
+      png_set_write_status_fn(write_ptr, NULL);
+#endif
+      png_set_read_status_fn(read_ptr, NULL);
+   }
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   png_set_read_user_transform_fn(read_ptr, read_user_callback);
+#endif
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+   zero_samples = 0;
+   png_set_write_user_transform_fn(write_ptr, count_zero_samples);
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   /* Preserve all the unknown chunks, if possible.  If this is disabled then,
+    * even if the png_{get,set}_unknown_chunks stuff is enabled, we can't use
+    * libpng to *save* the unknown chunks on read (because we can't switch the
+    * save option on!)
+    *
+    * Notice that if SET_UNKNOWN_CHUNKS is *not* supported read will discard all
+    * unknown chunks and write will write them all.
+    */
+#ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+   png_set_keep_unknown_chunks(read_ptr, PNG_HANDLE_CHUNK_ALWAYS,
+       NULL, 0);
+#endif
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+   png_set_keep_unknown_chunks(write_ptr, PNG_HANDLE_CHUNK_ALWAYS,
+       NULL, 0);
+#endif
+#endif
+
+   pngtest_debug("Reading info struct");
+   png_read_info(read_ptr, read_info_ptr);
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   /* This is a bit of a hack; there is no obvious way in the callback function
+    * to determine that the chunks before the first IDAT have been read, so
+    * remove the info_ptr (which is only used to determine position relative to
+    * PLTE) here to indicate that we are after the IDAT.
+    */
+   user_chunk_data.info_ptr = NULL;
+#endif
+
+   pngtest_debug("Transferring info struct");
+   {
+      int interlace_type, compression_type, filter_type;
+
+      if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth,
+          &color_type, &interlace_type, &compression_type, &filter_type) != 0)
+      {
+         png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,
+             color_type, interlace_type, compression_type, filter_type);
+         /* num_passes may not be available below if interlace support is not
+          * provided by libpng for both read and write.
+          */
+         switch (interlace_type)
+         {
+            case PNG_INTERLACE_NONE:
+               num_passes = 1;
+               break;
+
+            case PNG_INTERLACE_ADAM7:
+               num_passes = 7;
+               break;
+
+            default:
+               png_error(read_ptr, "invalid interlace type");
+               /*NOT REACHED*/
+         }
+      }
+
+      else
+         png_error(read_ptr, "png_get_IHDR failed");
+   }
+#ifdef PNG_FIXED_POINT_SUPPORTED
+#ifdef PNG_cHRM_SUPPORTED
+   {
+      png_fixed_point white_x, white_y, red_x, red_y, green_x, green_y, blue_x,
+          blue_y;
+
+      if (png_get_cHRM_fixed(read_ptr, read_info_ptr, &white_x, &white_y,
+          &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
+      {
+         png_set_cHRM_fixed(write_ptr, write_info_ptr, white_x, white_y, red_x,
+             red_y, green_x, green_y, blue_x, blue_y);
+      }
+   }
+#endif
+#ifdef PNG_gAMA_SUPPORTED
+   {
+      png_fixed_point gamma;
+
+      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma) != 0)
+         png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma);
+   }
+#endif
+#else /* Use floating point versions */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+#ifdef PNG_cHRM_SUPPORTED
+   {
+      double white_x, white_y, red_x, red_y, green_x, green_y, blue_x,
+          blue_y;
+
+      if (png_get_cHRM(read_ptr, read_info_ptr, &white_x, &white_y, &red_x,
+          &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
+      {
+         png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x,
+             red_y, green_x, green_y, blue_x, blue_y);
+      }
+   }
+#endif
+#ifdef PNG_gAMA_SUPPORTED
+   {
+      double gamma;
+
+      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma) != 0)
+         png_set_gAMA(write_ptr, write_info_ptr, gamma);
+   }
+#endif
+#endif /* Floating point */
+#endif /* Fixed point */
+#ifdef PNG_iCCP_SUPPORTED
+   {
+      png_charp name;
+      png_bytep profile;
+      png_uint_32 proflen;
+      int compression_type;
+
+      if (png_get_iCCP(read_ptr, read_info_ptr, &name, &compression_type,
+          &profile, &proflen) != 0)
+      {
+         png_set_iCCP(write_ptr, write_info_ptr, name, compression_type,
+             profile, proflen);
+      }
+   }
+#endif
+#ifdef PNG_sRGB_SUPPORTED
+   {
+      int intent;
+
+      if (png_get_sRGB(read_ptr, read_info_ptr, &intent) != 0)
+         png_set_sRGB(write_ptr, write_info_ptr, intent);
+   }
+#endif
+   {
+      png_colorp palette;
+      int num_palette;
+
+      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette) != 0)
+         png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette);
+   }
+#ifdef PNG_bKGD_SUPPORTED
+   {
+      png_color_16p background;
+
+      if (png_get_bKGD(read_ptr, read_info_ptr, &background) != 0)
+      {
+         png_set_bKGD(write_ptr, write_info_ptr, background);
+      }
+   }
+#endif
+#ifdef PNG_READ_eXIf_SUPPORTED
+   {
+      png_bytep exif=NULL;
+      png_uint_32 exif_length;
+
+      if (png_get_eXIf_1(read_ptr, read_info_ptr, &exif_length, &exif) != 0)
+      {
+         if (exif_length > 1)
+            fprintf(STDERR," eXIf type %c%c, %lu bytes\n",exif[0],exif[1],
+               (unsigned long)exif_length);
+# ifdef PNG_WRITE_eXIf_SUPPORTED
+         png_set_eXIf_1(write_ptr, write_info_ptr, exif_length, exif);
+# endif
+      }
+   }
+#endif
+#ifdef PNG_hIST_SUPPORTED
+   {
+      png_uint_16p hist;
+
+      if (png_get_hIST(read_ptr, read_info_ptr, &hist) != 0)
+         png_set_hIST(write_ptr, write_info_ptr, hist);
+   }
+#endif
+#ifdef PNG_oFFs_SUPPORTED
+   {
+      png_int_32 offset_x, offset_y;
+      int unit_type;
+
+      if (png_get_oFFs(read_ptr, read_info_ptr, &offset_x, &offset_y,
+          &unit_type) != 0)
+      {
+         png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);
+      }
+   }
+#endif
+#ifdef PNG_pCAL_SUPPORTED
+   {
+      png_charp purpose, units;
+      png_charpp params;
+      png_int_32 X0, X1;
+      int type, nparams;
+
+      if (png_get_pCAL(read_ptr, read_info_ptr, &purpose, &X0, &X1, &type,
+          &nparams, &units, &params) != 0)
+      {
+         png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type,
+             nparams, units, params);
+      }
+   }
+#endif
+#ifdef PNG_pHYs_SUPPORTED
+   {
+      png_uint_32 res_x, res_y;
+      int unit_type;
+
+      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y,
+          &unit_type) != 0)
+         png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);
+   }
+#endif
+#ifdef PNG_sBIT_SUPPORTED
+   {
+      png_color_8p sig_bit;
+
+      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit) != 0)
+         png_set_sBIT(write_ptr, write_info_ptr, sig_bit);
+   }
+#endif
+#ifdef PNG_sCAL_SUPPORTED
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
+   defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+   {
+      int unit;
+      double scal_width, scal_height;
+
+      if (png_get_sCAL(read_ptr, read_info_ptr, &unit, &scal_width,
+          &scal_height) != 0)
+      {
+         png_set_sCAL(write_ptr, write_info_ptr, unit, scal_width, scal_height);
+      }
+   }
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   {
+      int unit;
+      png_charp scal_width, scal_height;
+
+      if (png_get_sCAL_s(read_ptr, read_info_ptr, &unit, &scal_width,
+           &scal_height) != 0)
+      {
+         png_set_sCAL_s(write_ptr, write_info_ptr, unit, scal_width,
+             scal_height);
+      }
+   }
+#endif
+#endif
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+   {
+       png_sPLT_tp entries;
+
+       int num_entries = (int) png_get_sPLT(read_ptr, read_info_ptr, &entries);
+       if (num_entries)
+       {
+           png_set_sPLT(write_ptr, write_info_ptr, entries, num_entries);
+       }
+   }
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+   {
+      png_textp text_ptr;
+      int num_text;
+
+      if (png_get_text(read_ptr, read_info_ptr, &text_ptr, &num_text) > 0)
+      {
+         pngtest_debug1("Handling %d iTXt/tEXt/zTXt chunks", num_text);
+
+         pngtest_check_text_support(read_ptr, text_ptr, num_text);
+
+         if (verbose != 0)
+         {
+            int i;
+
+            fprintf(STDERR,"\n");
+            for (i=0; i<num_text; i++)
+            {
+               fprintf(STDERR,"   Text compression[%d]=%d\n",
+                   i, text_ptr[i].compression);
+            }
+         }
+
+         png_set_text(write_ptr, write_info_ptr, text_ptr, num_text);
+      }
+   }
+#endif
+#ifdef PNG_tIME_SUPPORTED
+   {
+      png_timep mod_time;
+
+      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time) != 0)
+      {
+         png_set_tIME(write_ptr, write_info_ptr, mod_time);
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
+            tIME_string[(sizeof tIME_string) - 1] = '\0';
+
+         else
+         {
+            strncpy(tIME_string, "*** invalid time ***", (sizeof tIME_string));
+            tIME_string[(sizeof tIME_string) - 1] = '\0';
+         }
+
+         tIME_chunk_present++;
+#endif /* TIME_RFC1123 */
+      }
+   }
+#endif
+#ifdef PNG_tRNS_SUPPORTED
+   {
+      png_bytep trans_alpha;
+      int num_trans;
+      png_color_16p trans_color;
+
+      if (png_get_tRNS(read_ptr, read_info_ptr, &trans_alpha, &num_trans,
+          &trans_color) != 0)
+      {
+         int sample_max = (1 << bit_depth);
+         /* libpng doesn't reject a tRNS chunk with out-of-range samples */
+         if (!((color_type == PNG_COLOR_TYPE_GRAY &&
+             (int)trans_color->gray > sample_max) ||
+             (color_type == PNG_COLOR_TYPE_RGB &&
+             ((int)trans_color->red > sample_max ||
+             (int)trans_color->green > sample_max ||
+             (int)trans_color->blue > sample_max))))
+            png_set_tRNS(write_ptr, write_info_ptr, trans_alpha, num_trans,
+               trans_color);
+      }
+   }
+#endif
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+   {
+      png_unknown_chunkp unknowns;
+      int num_unknowns = png_get_unknown_chunks(read_ptr, read_info_ptr,
+          &unknowns);
+
+      if (num_unknowns != 0)
+      {
+         png_set_unknown_chunks(write_ptr, write_info_ptr, unknowns,
+             num_unknowns);
+#if PNG_LIBPNG_VER < 10600
+         /* Copy the locations from the read_info_ptr.  The automatically
+          * generated locations in write_end_info_ptr are wrong prior to 1.6.0
+          * because they are reset from the write pointer (removed in 1.6.0).
+          */
+         {
+            int i;
+            for (i = 0; i < num_unknowns; i++)
+              png_set_unknown_chunk_location(write_ptr, write_info_ptr, i,
+                  unknowns[i].location);
+         }
+#endif
+      }
+   }
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+   pngtest_debug("Writing info struct");
+
+   /* Write the info in two steps so that if we write the 'unknown' chunks here
+    * they go to the correct place.
+    */
+   png_write_info_before_PLTE(write_ptr, write_info_ptr);
+
+   write_chunks(write_ptr, before_PLTE); /* before PLTE */
+
+   png_write_info(write_ptr, write_info_ptr);
+
+   write_chunks(write_ptr, before_IDAT); /* after PLTE */
+
+   png_write_info(write_ptr, write_end_info_ptr);
+
+   write_chunks(write_ptr, after_IDAT); /* after IDAT */
+
+#ifdef PNG_COMPRESSION_COMPAT
+   /* Test the 'compatibility' setting here, if it is available. */
+   png_set_compression(write_ptr, PNG_COMPRESSION_COMPAT);
+#endif
+#endif
+
+#ifdef SINGLE_ROWBUF_ALLOC
+   pngtest_debug("Allocating row buffer...");
+   row_buf = (png_bytep)png_malloc(read_ptr,
+       png_get_rowbytes(read_ptr, read_info_ptr));
+
+   pngtest_debug1("\t%p", row_buf);
+#endif /* SINGLE_ROWBUF_ALLOC */
+   pngtest_debug("Writing row data");
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) &&\
+   defined(PNG_WRITE_INTERLACING_SUPPORTED)
+   /* Both must be defined for libpng to be able to handle the interlace,
+    * otherwise it gets handled below by simply reading and writing the passes
+    * directly.
+    */
+   if (png_set_interlace_handling(read_ptr) != num_passes)
+      png_error(write_ptr,
+          "png_set_interlace_handling(read): wrong pass count ");
+   if (png_set_interlace_handling(write_ptr) != num_passes)
+      png_error(write_ptr,
+          "png_set_interlace_handling(write): wrong pass count ");
+#else /* png_set_interlace_handling not called on either read or write */
+#  define calc_pass_height
+#endif /* not using libpng interlace handling */
+
+#ifdef PNGTEST_TIMING
+   t_stop = (float)clock();
+   t_misc += (t_stop - t_start);
+   t_start = t_stop;
+#endif
+   for (pass = 0; pass < num_passes; pass++)
+   {
+#     ifdef calc_pass_height
+         png_uint_32 pass_height;
+
+         if (num_passes == 7) /* interlaced */
+         {
+            if (PNG_PASS_COLS(width, pass) > 0)
+               pass_height = PNG_PASS_ROWS(height, pass);
+
+            else
+               pass_height = 0;
+         }
+
+         else /* not interlaced */
+            pass_height = height;
+#     else
+#        define pass_height height
+#     endif
+
+      pngtest_debug1("Writing row data for pass %d", pass);
+      for (y = 0; y < pass_height; y++)
+      {
+#ifndef SINGLE_ROWBUF_ALLOC
+         pngtest_debug2("Allocating row buffer (pass %d, y = %u)...", pass, y);
+
+         row_buf = (png_bytep)png_malloc(read_ptr,
+             png_get_rowbytes(read_ptr, read_info_ptr));
+
+         pngtest_debug2("\t%p (%lu bytes)", row_buf,
+             (unsigned long)png_get_rowbytes(read_ptr, read_info_ptr));
+
+#endif /* !SINGLE_ROWBUF_ALLOC */
+         png_read_rows(read_ptr, (png_bytepp)&row_buf, NULL, 1);
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNGTEST_TIMING
+         t_stop = (float)clock();
+         t_decode += (t_stop - t_start);
+         t_start = t_stop;
+#endif
+         png_write_rows(write_ptr, (png_bytepp)&row_buf, 1);
+#ifdef PNGTEST_TIMING
+         t_stop = (float)clock();
+         t_encode += (t_stop - t_start);
+         t_start = t_stop;
+#endif
+#endif /* WRITE */
+
+#ifndef SINGLE_ROWBUF_ALLOC
+         pngtest_debug2("Freeing row buffer (pass %d, y = %u)", pass, y);
+         png_free(read_ptr, row_buf);
+         row_buf = NULL;
+#endif /* !SINGLE_ROWBUF_ALLOC */
+      }
+   }
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#  ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+      png_free_data(read_ptr, read_info_ptr, PNG_FREE_UNKN, -1);
+#  endif
+#  ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+      png_free_data(write_ptr, write_info_ptr, PNG_FREE_UNKN, -1);
+#  endif
+#endif
+
+   pngtest_debug("Reading and writing end_info data");
+
+   png_read_end(read_ptr, end_info_ptr);
+#ifdef PNG_TEXT_SUPPORTED
+   {
+      png_textp text_ptr;
+      int num_text;
+
+      if (png_get_text(read_ptr, end_info_ptr, &text_ptr, &num_text) > 0)
+      {
+         pngtest_debug1("Handling %d iTXt/tEXt/zTXt chunks", num_text);
+
+         pngtest_check_text_support(read_ptr, text_ptr, num_text);
+
+         if (verbose != 0)
+         {
+            int i;
+
+            fprintf(STDERR,"\n");
+            for (i=0; i<num_text; i++)
+            {
+               fprintf(STDERR,"   Text compression[%d]=%d\n",
+                   i, text_ptr[i].compression);
+            }
+         }
+
+         png_set_text(write_ptr, write_end_info_ptr, text_ptr, num_text);
+      }
+   }
+#endif
+#ifdef PNG_READ_eXIf_SUPPORTED
+   {
+      png_bytep exif=NULL;
+      png_uint_32 exif_length;
+
+      if (png_get_eXIf_1(read_ptr, end_info_ptr, &exif_length, &exif) != 0)
+      {
+         if (exif_length > 1)
+            fprintf(STDERR," eXIf type %c%c, %lu bytes\n",exif[0],exif[1],
+               (unsigned long)exif_length);
+# ifdef PNG_WRITE_eXIf_SUPPORTED
+         png_set_eXIf_1(write_ptr, write_end_info_ptr, exif_length, exif);
+# endif
+      }
+   }
+#endif
+#ifdef PNG_tIME_SUPPORTED
+   {
+      png_timep mod_time;
+
+      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time) != 0)
+      {
+         png_set_tIME(write_ptr, write_end_info_ptr, mod_time);
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
+            tIME_string[(sizeof tIME_string) - 1] = '\0';
+
+         else
+         {
+            strncpy(tIME_string, "*** invalid time ***", sizeof tIME_string);
+            tIME_string[(sizeof tIME_string)-1] = '\0';
+         }
+
+         tIME_chunk_present++;
+#endif /* TIME_RFC1123 */
+      }
+   }
+#endif
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+   {
+      png_unknown_chunkp unknowns;
+      int num_unknowns = png_get_unknown_chunks(read_ptr, end_info_ptr,
+          &unknowns);
+
+      if (num_unknowns != 0)
+      {
+         png_set_unknown_chunks(write_ptr, write_end_info_ptr, unknowns,
+             num_unknowns);
+#if PNG_LIBPNG_VER < 10600
+         /* Copy the locations from the read_info_ptr.  The automatically
+          * generated locations in write_end_info_ptr are wrong prior to 1.6.0
+          * because they are reset from the write pointer (removed in 1.6.0).
+          */
+         {
+            int i;
+            for (i = 0; i < num_unknowns; i++)
+              png_set_unknown_chunk_location(write_ptr, write_end_info_ptr, i,
+                  unknowns[i].location);
+         }
+#endif
+      }
+   }
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+   /* Normally one would use Z_DEFAULT_STRATEGY for text compression.
+    * This is here just to make pngtest replicate the results from libpng
+    * versions prior to 1.5.4, and to test this new API.
+    */
+   png_set_text_compression_strategy(write_ptr, Z_FILTERED);
+#endif
+
+   /* When the unknown vpAg/sTER chunks are written by pngtest the only way to
+    * do it is to write them *before* calling png_write_end.  When unknown
+    * chunks are written by libpng, however, they are written just before IEND.
+    * There seems to be no way round this, however vpAg/sTER are not expected
+    * after IDAT.
+    */
+   write_chunks(write_ptr, after_IDAT);
+
+   png_write_end(write_ptr, write_end_info_ptr);
+#endif
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+   if (verbose != 0)
+   {
+      png_uint_32 iwidth, iheight;
+      iwidth = png_get_image_width(write_ptr, write_info_ptr);
+      iheight = png_get_image_height(write_ptr, write_info_ptr);
+      fprintf(STDERR, "\n Image width = %lu, height = %lu\n",
+          (unsigned long)iwidth, (unsigned long)iheight);
+   }
+#endif
+
+   pngtest_debug("Destroying data structs");
+#ifdef SINGLE_ROWBUF_ALLOC
+   pngtest_debug("destroying row_buf for read_ptr");
+   png_free(read_ptr, row_buf);
+   row_buf = NULL;
+#endif /* SINGLE_ROWBUF_ALLOC */
+   pngtest_debug("destroying read_ptr, read_info_ptr, end_info_ptr");
+   png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
+#ifdef PNG_WRITE_SUPPORTED
+   pngtest_debug("destroying write_end_info_ptr");
+   png_destroy_info_struct(write_ptr, &write_end_info_ptr);
+   pngtest_debug("destroying write_ptr, write_info_ptr");
+   png_destroy_write_struct(&write_ptr, &write_info_ptr);
+#endif
+   pngtest_debug("Destruction complete.");
+
+   FCLOSE(fpin);
+   FCLOSE(fpout);
+
+   /* Summarize any warnings or errors and in 'strict' mode fail the test.
+    * Unsupported chunks can result in warnings, in that case ignore the strict
+    * setting, otherwise fail the test on warnings as well as errors.
+    */
+   if (error_count > 0)
+   {
+      /* We don't really expect to get here because of the setjmp handling
+       * above, but this is safe.
+       */
+      fprintf(STDERR, "\n  %s: %d libpng errors found (%d warnings)",
+          inname, error_count, warning_count);
+
+      if (strict != 0)
+         return (1);
+   }
+
+#  ifdef PNG_WRITE_SUPPORTED
+      /* If there is no write support nothing was written! */
+      else if (unsupported_chunks > 0)
+      {
+         fprintf(STDERR, "\n  %s: unsupported chunks (%d)%s",
+             inname, unsupported_chunks, strict ? ": IGNORED --strict!" : "");
+      }
+#  endif
+
+   else if (warning_count > 0)
+   {
+      fprintf(STDERR, "\n  %s: %d libpng warnings found",
+          inname, warning_count);
+
+      if (strict != 0)
+         return (1);
+   }
+
+   pngtest_debug("Opening files for comparison");
+   if ((fpin = fopen(inname, "rb")) == NULL)
+   {
+      fprintf(STDERR, "Could not find file %s\n", inname);
+      return (1);
+   }
+
+   if ((fpout = fopen(outname, "rb")) == NULL)
+   {
+      fprintf(STDERR, "Could not find file %s\n", outname);
+      FCLOSE(fpin);
+      return (1);
+   }
+
+#if defined (PNG_WRITE_SUPPORTED) /* else nothing was written */ &&\
+    defined (PNG_WRITE_FILTER_SUPPORTED)
+   if (interlace_preserved != 0) /* else the files will be changed */
+   {
+      for (;;)
+      {
+         static int wrote_question = 0;
+         size_t num_in, num_out;
+         char inbuf[256], outbuf[256];
+
+         num_in = fread(inbuf, 1, sizeof inbuf, fpin);
+         num_out = fread(outbuf, 1, sizeof outbuf, fpout);
+
+         if (num_in != num_out)
+         {
+            fprintf(STDERR, "\nFiles %s and %s are of a different size\n",
+                inname, outname);
+
+            if (wrote_question == 0 && unsupported_chunks == 0)
+            {
+               fprintf(STDERR,
+                   "   Was %s written with the same maximum IDAT"
+                   " chunk size (%d bytes),",
+                   inname, PNG_ZBUF_SIZE);
+               fprintf(STDERR,
+                   "\n   filtering heuristic (libpng default), compression");
+               fprintf(STDERR,
+                   " level (zlib default),\n   and zlib version (%s)?\n\n",
+                   ZLIB_VERSION);
+               wrote_question = 1;
+            }
+
+            FCLOSE(fpin);
+            FCLOSE(fpout);
+
+            if (strict != 0 && unsupported_chunks == 0)
+              return (1);
+
+            else
+              return (0);
+         }
+
+         if (num_in == 0)
+            break;
+
+         if (memcmp(inbuf, outbuf, num_in))
+         {
+            fprintf(STDERR, "\nFiles %s and %s are different\n", inname,
+                outname);
+
+            if (wrote_question == 0 && unsupported_chunks == 0)
+            {
+               fprintf(STDERR,
+                   "   Was %s written with the same maximum"
+                   " IDAT chunk size (%d bytes),",
+                    inname, PNG_ZBUF_SIZE);
+               fprintf(STDERR,
+                   "\n   filtering heuristic (libpng default), compression");
+               fprintf(STDERR,
+                   " level (zlib default),\n   and zlib version (%s)?\n\n",
+                 ZLIB_VERSION);
+               wrote_question = 1;
+            }
+
+            FCLOSE(fpin);
+            FCLOSE(fpout);
+
+            /* NOTE: the unsupported_chunks escape is permitted here because
+             * unsupported text chunk compression will result in the compression
+             * mode being changed (to NONE) yet, in the test case, the result
+             * can be exactly the same size!
+             */
+            if (strict != 0 && unsupported_chunks == 0)
+              return (1);
+
+            else
+              return (0);
+         }
+      }
+   }
+#endif /* WRITE && WRITE_FILTER */
+
+   FCLOSE(fpin);
+   FCLOSE(fpout);
+
+   return (0);
+}
+
+/* Input and output filenames */
+#ifdef RISCOS
+static const char *inname = "pngtest/png";
+static const char *outname = "pngout/png";
+#else
+static const char *inname = "pngtest.png";
+static const char *outname = "pngout.png";
+#endif
+
+int
+main(int argc, char *argv[])
+{
+   int multiple = 0;
+   int ierror = 0;
+
+   png_structp dummy_ptr;
+
+   fprintf(STDERR, "\n Testing libpng version %s\n", PNG_LIBPNG_VER_STRING);
+   fprintf(STDERR, "   with zlib   version %s\n", ZLIB_VERSION);
+   fprintf(STDERR, "%s", png_get_copyright(NULL));
+   /* Show the version of libpng used in building the library */
+   fprintf(STDERR, " library (%lu):%s",
+       (unsigned long)png_access_version_number(),
+       png_get_header_version(NULL));
+
+   /* Show the version of libpng used in building the application */
+   fprintf(STDERR, " pngtest (%lu):%s", (unsigned long)PNG_LIBPNG_VER,
+       PNG_HEADER_VERSION_STRING);
+
+   /* Do some consistency checking on the memory allocation settings, I'm
+    * not sure this matters, but it is nice to know, the first of these
+    * tests should be impossible because of the way the macros are set
+    * in pngconf.h
+    */
+#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
+      fprintf(STDERR, " NOTE: Zlib compiled for max 64k, libpng not\n");
+#endif
+   /* I think the following can happen. */
+#if !defined(MAXSEG_64K) && defined(PNG_MAX_MALLOC_64K)
+      fprintf(STDERR, " NOTE: libpng compiled for max 64k, zlib not\n");
+#endif
+
+   if (strcmp(png_libpng_ver, PNG_LIBPNG_VER_STRING))
+   {
+      fprintf(STDERR,
+          "Warning: versions are different between png.h and png.c\n");
+      fprintf(STDERR, "  png.h version: %s\n", PNG_LIBPNG_VER_STRING);
+      fprintf(STDERR, "  png.c version: %s\n\n", png_libpng_ver);
+      ++ierror;
+   }
+
+   if (argc > 1)
+   {
+      if (strcmp(argv[1], "-m") == 0)
+      {
+         multiple = 1;
+         status_dots_requested = 0;
+      }
+
+      else if (strcmp(argv[1], "-mv") == 0 ||
+               strcmp(argv[1], "-vm") == 0 )
+      {
+         multiple = 1;
+         verbose = 1;
+         status_dots_requested = 1;
+      }
+
+      else if (strcmp(argv[1], "-v") == 0)
+      {
+         verbose = 1;
+         status_dots_requested = 1;
+         inname = argv[2];
+      }
+
+      else if (strcmp(argv[1], "--strict") == 0)
+      {
+         status_dots_requested = 0;
+         verbose = 1;
+         inname = argv[2];
+         strict++;
+         relaxed = 0;
+         multiple=1;
+      }
+
+      else if (strcmp(argv[1], "--relaxed") == 0)
+      {
+         status_dots_requested = 0;
+         verbose = 1;
+         inname = argv[2];
+         strict = 0;
+         relaxed++;
+         multiple=1;
+      }
+      else if (strcmp(argv[1], "--xfail") == 0)
+      {
+         status_dots_requested = 0;
+         verbose = 1;
+         inname = argv[2];
+         strict = 0;
+         xfail++;
+         relaxed++;
+         multiple=1;
+      }
+
+      else
+      {
+         inname = argv[1];
+         status_dots_requested = 0;
+      }
+   }
+
+   if (multiple == 0 && argc == 3 + verbose)
+      outname = argv[2 + verbose];
+
+   if ((multiple == 0 && argc > 3 + verbose) ||
+       (multiple != 0 && argc < 2))
+   {
+      fprintf(STDERR,
+          "usage: %s [infile.png] [outfile.png]\n\t%s -m {infile.png}\n",
+          argv[0], argv[0]);
+      fprintf(STDERR,
+          "  reads/writes one PNG file (without -m) or multiple files (-m)\n");
+      fprintf(STDERR,
+          "  with -m %s is used as a temporary file\n", outname);
+      exit(1);
+   }
+
+   if (multiple != 0)
+   {
+      int i;
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+      int allocation_now = current_allocation;
+#endif
+      for (i=2; i<argc; ++i)
+      {
+         int kerror;
+         fprintf(STDERR, "\n Testing %s:", argv[i]);
+#if PNG_DEBUG > 0
+         fprintf(STDERR, "\n");
+#endif
+         kerror = test_one_file(argv[i], outname);
+         if (kerror == 0)
+         {
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+            fprintf(STDERR, "\n PASS (%lu zero samples)\n",
+                (unsigned long)zero_samples);
+#else
+            fprintf(STDERR, " PASS\n");
+#endif
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+            if (tIME_chunk_present != 0)
+               fprintf(STDERR, " tIME = %s\n", tIME_string);
+
+            tIME_chunk_present = 0;
+#endif /* TIME_RFC1123 */
+         }
+
+         else
+         {
+            if (xfail)
+              fprintf(STDERR, " XFAIL\n");
+            else
+            {
+              fprintf(STDERR, " FAIL\n");
+              ierror += kerror;
+            }
+         }
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+         if (allocation_now != current_allocation)
+            fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n",
+                current_allocation - allocation_now);
+
+         if (current_allocation != 0)
+         {
+            memory_infop pinfo = pinformation;
+
+            fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n",
+                current_allocation);
+
+            while (pinfo != NULL)
+            {
+               fprintf(STDERR, " %lu bytes at %p\n",
+                   (unsigned long)pinfo->size,
+                   pinfo->pointer);
+               pinfo = pinfo->next;
+            }
+         }
+#endif
+      }
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+         fprintf(STDERR, " Current memory allocation: %10d bytes\n",
+             current_allocation);
+         fprintf(STDERR, " Maximum memory allocation: %10d bytes\n",
+             maximum_allocation);
+         fprintf(STDERR, " Total   memory allocation: %10d bytes\n",
+             total_allocation);
+         fprintf(STDERR, "     Number of allocations: %10d\n",
+             num_allocations);
+#endif
+   }
+
+   else
+   {
+      int i;
+      for (i = 0; i<3; ++i)
+      {
+         int kerror;
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+         int allocation_now = current_allocation;
+#endif
+         if (i == 1)
+            status_dots_requested = 1;
+
+         else if (verbose == 0)
+            status_dots_requested = 0;
+
+         if (i == 0 || verbose == 1 || ierror != 0)
+         {
+            fprintf(STDERR, "\n Testing %s:", inname);
+#if PNG_DEBUG > 0
+            fprintf(STDERR, "\n");
+#endif
+         }
+
+         kerror = test_one_file(inname, outname);
+
+         if (kerror == 0)
+         {
+            if (verbose == 1 || i == 2)
+            {
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+                fprintf(STDERR, "\n PASS (%lu zero samples)\n",
+                    (unsigned long)zero_samples);
+#else
+                fprintf(STDERR, " PASS\n");
+#endif
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+             if (tIME_chunk_present != 0)
+                fprintf(STDERR, " tIME = %s\n", tIME_string);
+#endif /* TIME_RFC1123 */
+            }
+         }
+
+         else
+         {
+            if (verbose == 0 && i != 2)
+            {
+               fprintf(STDERR, "\n Testing %s:", inname);
+#if PNG_DEBUG > 0
+               fprintf(STDERR, "\n");
+#endif
+            }
+
+            if (xfail)
+              fprintf(STDERR, " XFAIL\n");
+            else
+            {
+              fprintf(STDERR, " FAIL\n");
+              ierror += kerror;
+            }
+         }
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+         if (allocation_now != current_allocation)
+             fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n",
+                 current_allocation - allocation_now);
+
+         if (current_allocation != 0)
+         {
+             memory_infop pinfo = pinformation;
+
+             fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n",
+                 current_allocation);
+
+             while (pinfo != NULL)
+             {
+                fprintf(STDERR, " %lu bytes at %p\n",
+                    (unsigned long)pinfo->size, pinfo->pointer);
+                pinfo = pinfo->next;
+             }
+          }
+#endif
+       }
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+       fprintf(STDERR, " Current memory allocation: %10d bytes\n",
+           current_allocation);
+       fprintf(STDERR, " Maximum memory allocation: %10d bytes\n",
+           maximum_allocation);
+       fprintf(STDERR, " Total   memory allocation: %10d bytes\n",
+           total_allocation);
+       fprintf(STDERR, "     Number of allocations: %10d\n",
+           num_allocations);
+#endif
+   }
+
+#ifdef PNGTEST_TIMING
+   t_stop = (float)clock();
+   t_misc += (t_stop - t_start);
+   t_start = t_stop;
+   fprintf(STDERR, " CPU time used = %.3f seconds",
+       (t_misc+t_decode+t_encode)/(float)CLOCKS_PER_SEC);
+   fprintf(STDERR, " (decoding %.3f,\n",
+       t_decode/(float)CLOCKS_PER_SEC);
+   fprintf(STDERR, "        encoding %.3f ,",
+       t_encode/(float)CLOCKS_PER_SEC);
+   fprintf(STDERR, " other %.3f seconds)\n\n",
+       t_misc/(float)CLOCKS_PER_SEC);
+#endif
+
+   if (ierror == 0)
+      fprintf(STDERR, " libpng passes test\n");
+
+   else
+      fprintf(STDERR, " libpng FAILS test\n");
+
+   dummy_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+   fprintf(STDERR, " Default limits:\n");
+   fprintf(STDERR, "  width_max  = %lu\n",
+       (unsigned long) png_get_user_width_max(dummy_ptr));
+   fprintf(STDERR, "  height_max = %lu\n",
+       (unsigned long) png_get_user_height_max(dummy_ptr));
+   if (png_get_chunk_cache_max(dummy_ptr) == 0)
+      fprintf(STDERR, "  cache_max  = unlimited\n");
+   else
+      fprintf(STDERR, "  cache_max  = %lu\n",
+          (unsigned long) png_get_chunk_cache_max(dummy_ptr));
+   if (png_get_chunk_malloc_max(dummy_ptr) == 0)
+      fprintf(STDERR, "  malloc_max = unlimited\n");
+   else
+      fprintf(STDERR, "  malloc_max = %lu\n",
+          (unsigned long) png_get_chunk_malloc_max(dummy_ptr));
+   png_destroy_read_struct(&dummy_ptr, NULL, NULL);
+
+   return (int)(ierror != 0);
+}
+#else
+int
+main(void)
+{
+   fprintf(STDERR,
+       " test ignored because libpng was not built with read support\n");
+   /* And skip this test */
+   return PNG_LIBPNG_VER < 10600 ? 0 : 77;
+}
+#endif
+
+/* Generate a compiler error if there is an old png.h in the search path. */
+typedef png_libpng_version_1_6_37 Your_png_h_is_not_version_1_6_37;
diff --git a/extern/libpng/pngtest.png b/extern/libpng/pngtest.png
new file mode 100644
index 0000000000000000000000000000000000000000..66df0c4e6f6d13981148bf2fbb85df2b797028a7
GIT binary patch
literal 8759
zcmX9k1ymc)(*cSW3bZ%{no!&+(grJT2~?ms!6{HYxEJ>V#l1m_Yk@#<FYZvRIKdr)
ze);{sy|-`2?)L5N-0a-Uguhc$Bq5?B0ssIc%1Uw{Fryx(%M;)M09YUPi`Oy8BTH$h
zGyqT)`}o!v7lUIte^8Xcn(OEG`;X}?qpX38Y0!M03k?3kROtg00Pti50Q`dhfNKoN
ze;WXB;RgVAi~s;|3IIUukkR;F9K*nJ){y^z^=tiC1_mK?b&$5ijAsAqp{$0R7y!>i
zRZ$M`4|Dk^4)MLfPzdc66r3L(9{!t)0;}0`_d5pQc94~ZnAlsoIKObQvw}NgNdL8m
z2LQH(y*;0au@gXmm*1QpAR^2w{7TsTmDXFY=NN&f&Y1hK1YZe>h|2T45d^#v5E2lP
z7g_fssmE{$9h7u1k9z#<zm5e+%b>v!@!`r)dHg{<d~z^B%mb_Ee{yhnZMcRN{EImN
z^EMZ-JcI!Nrg~*LX$|*`{S5WbX8oC4Qg0HzF5?h_+P+eU2zI?C6>q2efG@lGl@$38
zi*gW%YxDDO`X>K7pN~UDH<dUW={wUdG?kkLV4Clt0n_aR>&C>Xm3S<Wz@^+|5?Rr%
zKu&k8%%hHP&;y`hK^~{3i{|`6mD_EgVm{|9=CwP}>gCqW%{}8S&`f)FY9uy<%fHqA
zeCV7WU!n>7YW;J=pG5vFFrX1Y8q)2tu{&02Nds#v1g&F>Z&Pz2g0^a^alUb(9&p=E
zl|53ppvJ^1>sS4qxo)|PI9(~e`#F|cnqf6V-({k{m$MG!z_So5_kEheE>Sc*>~Xss
zSXZ<BE|dU?lB*;5IMz?e=w5`67xwYRkR%;d34W&u?$OxKdKK89qP@nVuGn(f?XDtX
zs<KZD;OB7~&4#!~=iQ!A11x*-OFYos!&`hX;-rBnZ$-)7g^bfdkBEh%D|Fr~i8s2L
z>b$An?L^#+0cCV0*Sf(iuD8qT>Yr-*DNG-&xh$WZS!=J)fbsct8%~6!ygb2nbPBl!
zIRyb(!d3|zV1xnxMbswz1LKoRVru6Z6m^J_*+IuSL+oD$cVF)#h0F)sw_p68{5wL)
zZ_O8@Gv$MRCzp&#k6fQWxGY};H?1ciRyeU^=b@hPQN1@?@8f}>F8cKIX$}b~No^k|
zA^lA8hNVb0#k;9F5{XP`MWqTB>fJ@O!b|3^5Kg(CS2IZGqoPwtg}C_!8nYui)aXAq
zeei>;GsOGr0Ht685iKqo%2a{`<ST$mJ0fst2R1*lM7L18d$=10pyhW9P=z^*q&mBb
z>kb)Ar4OrKfBLA2#nK_&dZZ#GcO<z`M&%zMOv9tE4=x?kW~NDuGw&FisCpwMdDKHN
zVp%>RL>5k=Fp3>KB%sS)a&-MKcnqRn?LWTMjmq02zH}OYt8tla2oECm$7qA|)!C2J
zn&aOSHF$_uyu6D>wsCg-Y>J&zKkc<*Lz*>5il6xhW=TkSjKZ32PyG<=z=vtreL@mG
zX5Z^=du^IFeB{H|nWC>txD(b8##OpE*_Vvo+UtmHCWg`&-5DH*6NhcpY-0O~x0Fi`
zx3ENYMq;h(=Om&bedxBqH^Z#?Sg$?!^@o}j$#%dWg8Sxby?u_dG!YnO*?~#XmBo;H
zZUNTNQ&F3q)Eqp4W*I*j&mt4ezMckfPRg~-oL`yvhT6WNquSDvbO3YEUhHj;Nmr#M
zP4&^N^uPBj!`t=wC*7*8nQO7ksj`*&U31Ii0BlbAWM-#HxWRtBRR^z}D2xE%yP^t1
z^u4CLP}}5v9x}^cAr6Iz^aamyIJvaMNDjx6e)^~dwI{KwhUe{qSG}X{w3@@?B2{~j
zKRaaHhZq~r)uhodcY<I#2+^t_08Too9Z7kG8<{R)a`_J;avLEPBVBO0q(|*IC&H4%
z<(XAjm>EGo6(PTy@bvb4U{hnNJSZR}YwYtQmj1mE0w&2O{?l>W)t_W^GK>7|@htie
zZ=Xqr{}yzoEVvQbLIh%|v$60_mQESfI>1LynX;kymzO*WMjt+9o~9!B>6Yb6$>DfP
zU7U-p!dK|YOoF48Q$i%c^ygZt;)0?yRu6CLj=`Dp9@Sy}sc>?}Cq!?_$nmBzLS|0(
zA&H6Kj1!l*ArtR1qqZavxUgQ@wzaLAnA39$A4bWhZHTJWM0}OKi_3$;Psf29#Wrgz
zOIGphp&{v!EN1@HrlA=268;u+b0PI9mRn!hT19m&yGoE{f(QP;l^hz>g+{rQ8<>Oi
zkZ!Nc$=AD5x3|4j>pke<jl}!7l9}poDR2L4#{U?cvLqzhW#j?lQ)fh-ciGYQL+8z=
z3-(+R>9LZG`%+CQO*IqB=&MbyY+oT=H0R0QYP>#+-Yz`H%4nI>B&s6%5`W6QJg?P$
z2(GOiMWx1OF3j=qH8Dp$!-3wT6n!v=L?wPdT+RgY#=&@UQ?6n|&*nDA@~$&r$Y;?g
zdb8i%^R-+3e)L#>L2{y^)qv-?iW&TM<rczMIxKFYpG79*DKyNg0{}ufN#+EJciEiQ
zq`EhK-*O4la0w)s6!_5C)-r^#Jjl~48d~+mmF|VqNaWgQZAjwuU94i@sWQrP#Ew>x
zb~3k}uDb;q;XBIrNhj&nlOPVPkOokarNp8uD5vY{+p~@EvMpf;`ibw{;1TTRa2M?D
z<yaP(nt7utQ~mwl6ET4hS@}c(U?Qe0!=?z|xC+642!w1_rU98rV0@Hx+(b<X4fEyl
zx9$sD$;RdSksxlqQhvVOx!$!o+mYW%WJQl=MX#sxCI*y#(m%Oy;`M<>{VVZ*-!T#S
z2K4ol!~NJ8r&hmfD7elY3Vq?>sdO-`Nlp#w1j&CuWEqsfn9lZ8O7?E6OHVpDWx`6?
ze73r<@}e6X9MdYiqf6*t29Cbnz{xfQ^BP2t(@F|usHv3eM~@xt9n1RNue<NaikC1)
zv9TcTu+w+Hcgc?uMd)LZj4ws0JVqj4a1^S&ojTTIYoS_}`vYFxQNsJl-N`<bU$RY|
zByC)YWWBOT*cmbC{&#G}Hq97#n9UG7{P7D_l}ebv({TMpqAi<Zvi`)SE*#L;X;l2h
zVX+;%lf3cdyzqgyM4(v+5#lwwQ;gzG7v69IOSv^cm4ec&oUyP1Jc5x~n*|Z7&Ii^i
z?+9({Y-enVxgtvi`)!wmAS)b!8#A2}fzw9N@ng>puni8Hj6lF-(uEkabhhM!mpw|X
z%CZU7t7}^yhb^>}ShW)&$<tpIjwHuz803v9?>aJYZWmE`&rD0@j2f~{opXsC#ho>K
zHFG~UdQNwRy_Yd2eqp9lZQ;T|PG0)qtgJnBUTr)23488a63b_bah6>vLUHCCB$Kq0
zBtbNmE??9Rs4o_J{a=*X@`{>LBk34OE=T73(7%=``m)8hy{59tX8mJ@KiO2fBBZ=U
zJQVRKUuxv_;pi6fkfrZ7QITgYA6dkbUL2dhD4=YjOi$9J@e|KVNeGpFC}s`_Di`;a
z^y1^Y@98W$KS!z=eUKA;2O3myyE<F-99Qf#*^tdEf9Ad+^Sl*o7^Oit9jCQ?{pqBq
zN!;suWfXY&HIsC_Y$Fo)MZoFsl;ta}W|29myoEQ%3HW!3W`tuIiFUWBe6b=K?~=#&
zHMb8hkn#6^XU|*SU(5S?3vsJ`|F)%~pw4&(Q}u1FDcwq6@BeuypP-oYE)68w8%!?K
zVR=Hf*7N0lL$3!tyuRK(YJd1;<3aE)W3yyg@ZpvP_M7-NaV|GTbzz{wLR0%oW#2Mw
zt`9XiP-=T_Et{!1rc{dVqJT5u_KTBzxu6V$HfFk`FqskSqO2u&{8qZYcMcIq880(V
zwsN+5l4Mz{5)&#hK^;c{4GH_e^LCEvwS`vJQWk9+L(U<SjAS!68m_yF;|+F!{Q0xs
zF7~j!^6$~V(qNKk<VD7A&}?v+NB386F6g}exm07TRCyZfp<bt-7w$yEz45o{;8r4F
zl;?EdyHF)c>sqsP`{2H^pa%GP*`Y5N^oFxxd<Hp1>rB0*i%lXBPYB6e-Wzy7QeLYD
zw43r*3VGT-6URBKkct9zV2)5v=fN4FvY=ascjCJ`uOgtbBXs(dqblxKXB~1sK^p3O
zo0)5YOU0EOThGt;``tI~uwDa&);U?8C~$oYj%XPw409N*32V!P{HoKywIWl_b!14l
zJ}4eD(7CnHk&<96lOdk0!p!JnlQPKQf<uZ=#q^;=80j?S?n*M5!N63S24D@nk!s2e
zV2dsQEO)=oG6ZXBJ9D>%UV2SJ*S~yP)o%{Z_hIPWP3ulKtC2X6VsK-WOoxLomiI@d
zLs;DLLX{<DRY1F8mK4UbG>*&0DSDaP7TU+=R{8AFkwAQ8O2_sZ4Kq+7gY=4w@Elx7
z9GXzQ^V_OJ<)z;!pW45e{gqvc7@`-pX_TgBPAC**8q!906c)><)BJ(<dy7I}rNZ`{
zw~&43ROC1b-n3d7IiAFPcH)z%r1E(%Y5pmWn<7Oj7mAd~`O4wl^BEums@0|{dFIIv
zs-o}1Khrf9igw{qK2d`MX&s+sK0CO4A%*lLmavz0^!6bF+tHq-G^yyuo*Aq%;g%SP
zL9x)-W|T|Uue9gqUnCi*(AJZDpS*e?vPL*uW}+uyGpq)oLaBEW!P6Wc)wsy|pdqKi
zBr`~iL9T|lgR`ERc4m#~`<{HRflmJp2P?dMc2U;;lejEi!231(ZDnPNwDEBCpX+br
zrgFN4a2-z*9Hgfz&*an!aof#z72&cT*)M%|-fGI8>eW#N;X-*YDd~0qcO4g4<=)^0
z-ACz`McOQ1AG=idc9BdyYB&dDm&bh0e7Y^F)(Ah>0GO5wgs(@u%CP4LBZ`?51gltr
z)_?pmgA7D)G4(y-Rbzx=)xLD{CnJCQhE-XC;e&$TGZ)YE2mz$)*0Lb#m#LFWp50%X
z7hg$9BuX4xq|GZWDRhN~XTsh_k*GYb8J8|aW+Z1kXMmKAt*d;zZj>(?|7B>KzH6gi
z{r+@F?llm{$ut#K!#Esj#cCVEP=R7lF#j$YpH93BPe&GVY(ofgb5Dek<B*DC6~X>!
zCD^aM)Xkogx-Bxq)A_aW#SGI9z0YQ*#-O+%CO0dvTrn%FjqzU-*rSl?A3}ozbT%5R
zjlX}qV4;ocTibeuz;(jKxKeWb*e%xVB|(3ZBsDK)-e(Tae(5bhW|=AoJ`ol6vD}Lz
zqyQtgI@lF%sLF7+=v59=y;@iL6M5g!B>Wk2ica@-a`Ye=C7a`O(hvJCNyGDDDtBdd
ze9apgRy11j{hcUkURTxYSrLW76v?&iH1pj%LG!zgckIy5bi;hAtoexWZ>k|5s>8dY
zRKm8?{!P@Q(Sw?6)kGRDopjhW3M8!N=AdJ%EJ8`S-?21hsZFD4jT$0aDl7vspc<@M
z5xHiuKauaWhr07k4Lu|?#k@cBbE>v`LR9C3jH3SfhsZRNmkHt=t)TJ{)!bIOSUlSP
z$j7l;<$^70bz&k#t`#m$-I`$<z;9gb>()5;H#Cd%Y_`twC~F9-K3F{}ygXTmUazcx
zB}$+!2mMRJrDe&zdmLRQ5Kllb{iS1qVCqz7E>#Rx7T{YlX)(XS89kNv^J^s1i%t)6
zG^{*gkYkyU`jk9E9Qm(<9iH^r0R<o`OsF<JF|$p4yC~-!HgT>!!n%?B4KfYwb-cS@
z=qf0(ZcB^uDdBJmo}w$EpmhKv!M}Cty=B7#bx_O_HX^jaQ&y<mBp|S@CK4H7)&frg
z$&^q6m!9}DVtnJO03Vx!mz9#flCMU3YLW`rC=}Rs40R;#+{Jf)M^G=N+Myebjf5rj
zouBXE{Ywk<a6~ay6cI>v)ng;fDJ|lg8N{OFb~N>`p-zPbs!Rn%9mS%C0)ZlS{yL~$
zbIS6MIjrsNE_ZaM?#!|3mYM0torfU%O2)Anfw|sa>lQ<k;gCPp&wi46anR1b0z1-V
z`Z1r~9HTcfxf7NL@>F4B36FPgN9vBg6Nr1^7S`#;P8azZW9){d{k4Er@bY7`TULVh
z8<E(01$Lh{GmK+)!fGcyQv7~`U((z2_<k~NS^6NOcI^5a4dMR5XsUxR>WRIRKVXwL
z3dVEmM}6`)??&GDWIN||40*<7&2he%M<Uj_BAeTo+da2mlGH$bqJIB2=I1gtq#G^j
za}ir`a?;BxqII{@;$a=VQ&`H~x%st3m!PEFQZwwXAfP=<ItVM_q|EeQXHGP)PxE1|
zvwe0(pk5&bJhEQ>bv8#M<TbD^BX*?)MfzA?2e+008Gk$Fv`})Q_&)0<mWpLv{r=`C
zxl`gs%B_`cp3jfo!}a(u=tvkXvbV#qYSItloulfj=7qKBADLAB!{_NM{`D?c{v54`
z-6h4@vVRltwEr;z?`B&3Ifcc``1s;SqeK(qjv_qx_RN~Zk+<vZ4u{(HWWy*kwI~v#
zioe<CQ+M*dYO1us1}uO13)`5nG_J#5Df*FR8o)z;8hJ^c)I$A4WB9B%hc$FCJt?a(
zW>Dqw3L5cA=3yl#B~3q<MOt~-D@rZgOojicE;6Y=`K_T(pek*EvX0|BGvdc$*R-di
z!)PhU9B5r4U8+_kJwP~cVs4|~%YxP-8VYM9qHq5k{YeHM7m1|*9bsRZZ#m@=myQX|
z=p9(U6e7td?Mivqqko1sZGf{Mr&L;z`;Y#zW76ZLs%xuvAO~74@$U0%`jf{KT09h=
zdX+ZlYpK*2iAUI+MQ`TlujLJ&A$7*7ipeT@INWz`Cz>eA<P<tPG9n2=aUxISBoN0y
zCmq(-x^m8nM14^nQE?g0B{O>cE!KD{le{xw37aQ=6@P{k&whoWbR-&D?V0MNGGT9E
z!F_P24Yh;ocFP3xKe*sXsDzjn2<<TPZ8xe>jb^>l@<un@PcZA;aD%ml^Q$%!eQlmh
z>hMd=vma#icHO^0XQ9CiTyf%0s}!)lS{aAV3en$ME#__PrnsUN1cPiILI2`9xJX<8
zGlKf|R)?q_xd&D!D%pJ}_WUHZ@X8wQOjxFN4qyURSvg3$(5`dN;Zm>u>^l#ml4Vd|
zbQg4so&F~mwDV)1rd-BHlI|cHqBl>3MT9tIQ<QzUf}5=BQSj0#sG9g5&f9!)vwM`-
zkJpTv_qNuUhNTA)uiUqEql03SH913i>w3KP+P`e$10+RWZFML|IbL(lp71)c@yu*m
zkJenT81XU5w<(2`&`-y>`>d0F<EDI?&bngL*?}F-Z-5S2Fe^fUG_@_4diCB81hz;p
z?ajp*P(PcOFE;6%E8JK~f18>$G*b3Q0VqO$3M5d(zsXSJ?WIm0J};Fl$mdraH_>H|
zy2kzHKY&N0u9{IHTIK|R<~g~%#<;|uGlzck=$_GvzNybb+`}$)yaNHw=OLk!3$p~8
zN<z0QE%F@gS^=ZJMmwBvRv~B*gdYS^xzvv2-<wMS%Y{g&5|G0bt?4dmEp`lTZI$D>
zX!rF_xto7K8DnI45)SP|brX{VgOt7y3W6%_olhV&mXunO!f<iSp^+#Fk&R;Wj$~+B
z%ITCi9bNxJpwnte=}c`g!duX5!`dVIcdwerG&3JAJW0~B@uSonYC(pD&@9o8)g+vr
zRyoR5uta%0Q!xJ=Z@FB*DaRpg_0trTEb+X+K#?T6Er;L7Cd$uA1hqIgTujzW?JRmg
zjjWJOu-v^S{W?u%V*Nz=L$q)$B(9^Npl1{Bu-SU`I2}Z-6r=gbCfYMYI*V)Q?yk$T
zShlOy>i0KmN6j#Acd*C4MoU8A@888eojziMD$KxDWhk?#o6E!}`|0tTf4dsqb*u=>
zk6X|v2g>+y^F^)+5n>CSb-18qL$dBa@30j8T&I5ZSjGFf?mY)Vw|cu5lVe4Y6BjOL
zkif59%5+y1nc|mbWWZP9v<;RNTD&=ev=m5B?o{I1Zv)XgmuYKBhN9^|ZqT(03;XRY
z-JI>gwdC{b)*m114~XUOGA&F<ElNiu13`0CFdRqne%BywJ=Wd?mRC=cU{%@*uJ!fk
zw$DkKPo^R@lJAEiaY2=xR2HIdO6{oY8Vw8;w0j5!SRO8rmdagw2V~5*ZJ!%6d3=Av
zZqJsQ7c*f)QV$!Rc47vTku-jwOkP;cdZ1Uxei@G;FI7;bk(-$809AE!Fv0CPX&q`D
zs}bH*sm+Z}yGqz_(n;C>l728<=5^?5-?C&v2v4^8Wd65Ipab7Exgjjbv;ROX+3#Kx
zO<J*YoJo^VUOYln!cn?ZdLkV6cqfhIBP;nMAs3}ZC0!-`qJs8NI<2XOQ3suZo(SRK
zi5&{NL`^Vneo3m~^*Xb6v=t%#<xR8c1Bxx3jlVSW;`%&|-Rk=iyqb+lZUAld4CurB
z3+CtM%&V7%Vr^+TPNUD(dq^(90oFp_3thRpJ-ZO&5EDUds%jM?zMFq0373B=+8?a+
zLrRmUNDHu)F1KBVU8Qr1Tn*W%le|}`PMS#Uc^8ir=Ycu`z5~a`g*nIkZMxmrVk(Oe
zKMW-sDODaM=Alj2dU9xUa)Fi=<x|=;MU<wbK#(8I_T$SO$yhixsS>xjtcO-sdRS(B
zTw7w+Ro<ntPR4ZxG<SOjy9qIi&Hsq;y`53)G3zo9<!iA{5gQpuj+561E%H!R0ee_r
zJjr`XA@Q~?6>j`Zw0yf24t&^p472^Nqw}<jcHrqIu@0wH0@uimcs@ggI&ILr9yf@4
zHGW`xL`MJK(@igeIubWmH>ajzuKqFxG@!D5`!a!;CFfjZUPlnu?$jtt$*f<HSBD#P
z8AWDV=yRo>ocSekyj3oIbl=rpzaIi$Nqn%cxM*gn%ybbD)7#?&-iuV5>D(2U`W`R+
zc@lY*Kec>wlMJ+TtFN2=t9zn(r<e3)Y~QXbCs(H<$!yQg{&<bl>Eh68A(F1;plzD!
zUfxU(yl0)OO5HpWY@WRFl*&<Oaeise7peU&wC@wOiGBetmamcPK_*m^K1oxe=>ayV
z-m1$Trs~gf>FVZNU9-4x$_E=w<VoUrW~mkQa6Y%ijUr1f+qbRQ-{;j+9R;sNR<?a{
z(;3e{b;+y2)!YB2-%=jQ9azTl#e61vpw5Usw`oe+{;@H6e>DU)xL8JWm#K5$C4!jw
zyVt1Zuolf>^s>|1xWO`jczIkz-{6&7i?A@Nq0BMVg&@_OW3EqA1^E%;4JCzYh*vpl
zMaO0tq(B}qVHbBRz6=apVg%~fuV2#?F{|&+{_`GM$S;8lucfLEWdrNx>W%&q<k^)Y
zxHBC)Hw#<m=W*@Qe~u=d+1I}KZBes~bkAuL3{#Cbn5Js-j9kp*y_^(rbxUr&Gv1Lt
z;H@7O>yTL7(8~6>&%cf5lYNwQCEsap8oF<Xy<A@xAD+_`wBd9-bLm>|QYVk1?w33u
z;M=9h^fsc<t%K_X!@5`^k1M1edb2eB5^T*c2VIksUF6L5Znp!yUbh-)b*hQ3?JfW5
zeE1mbr_H@8b+?UkDs`}LF+Z^Ub(E#6qDsM8oe;>|U(Gwf+h8rN&pS8N7)CIUJswP!
zTq@cKFd(lkZ9;Cd!fJl~GIP`Wxx?~s<9w;^*uUDGXzS{BaJT<&Ngce%!Uq%jtu5z!
z>eOxt`@Q}Oc3e`u+6_8MEooqHZR4ZjPF8ho)Ppx2;WP)ro4Auyleovk=D$G*#uN8T
zAB)XV@lnT>mGMS`t9d#O4n*d$BbAQZn=@PaS|M@;u*4}VeO@<TGdFxbY7U5ZRTyS<
z22?Kii278&`|eWRE+@jsk&>g@Tfy5k5U(G))9cz-YnHc_;CA%jWD4809>@)*kRnTh
z7bUAw4d61gHEVz4Y3hrqT->j2UX*tW&a_Lmb5nLFN4X}Y>{Ar)Wb#H<B!7oZ)+9$Z
za6npWs_S1x%`M%b29imZ=lic(h8_5*;iwZq-)=2OWlC&dNAtc}Q)`8rcJ)iV_*J*Y
zJu`!|X%R=-xxZfxnxTaWuAM(zj9|49)3jCrRB@G2SH<X!WaBDFaJJS;vibRxrPTe(
zr5_!YYApeb+qzLtwf1kj=E^`dQR{CHCPySDlG^d{()@}ou^)!jeK7n)58JUy?$EAE
zzr$6lZ@Zdj-uv!6-hwbwP4M10?nN+lq|(+d%kn%WUbjRNj1Ohk9s@^j^|wmhpW7SW
zpAIeiZdIpf7W<tz@Eas&VZH?ppPScTA7N9X)8-k&R~l`e*qO51%xfhKE}#98;*Hu|
zseG+-xox)391}#*y90Thy<|W}2J{o$x%pwMbOH_R7c`j|WR%MGVV30mhDqc!Q{~2x
zFAMFVqF7}<)9v(yJj#fBTNl!$$p-;}=93t2Q2F#y*^76x`EETm1_ZByNCfNcNqD=4
z)<jGo`7f>B)c?reSou>B^*yU3k@2$N*IS0-iMlZknFoTWzy_jpZPB>6;KuN&^rJ|c
zk4*Rdf%h7H*O;^-N9LRxvc9iTlTks!OK^51_Tykhcw39Ix@9FRFaf_gNHD1d4{NJq
zuistdnw9vznW#naZuQp4ND=haIlyD%Sklhb!8*2~d}=KIpynbK3)pksI)$E$Hq=}i
zVahKk^*||4Wqi-qW!4|On?RNrs!|vxVlrX02V1>D@3cER3r$a<D((sFKqjh-DmB9R
z#ri*x0c-H(Il4Yqr$sAYLGZZ%%i|sbGd!UA@Gf3JdIYPgB9FP&i}xvFQZ359i%~r5
zxjqYVwU0l}gm2I@Ux9z)?JclSJ6~RnqfcW=@h8YY!9(~pC-V}jK)K@M+s21u^kJWg
zPlet1_{>s0>6`E}i6$)CymE>7ap#0_^EelKD8`!+b>jeQjr(CjLv(@KYkazo3l>+V
z7}Wo`CujhNCB-x0J2YH8hZZU=k3A|f4Q9r461CrcBJ@adoYHsurj7VEJ^Tq6w^2ft
zs^8ez#K?uMJa&1xKUuer>jIIVRfX9Tm1x}$X&lz~hZa6N9m>8wSeF<I`vM8GVF<Cx
z-mU&rZC@fx-afVRsqnBQo(si95^1GyvICe<m71o7l;7$^jV({vUl(#7ZoIH9zs6`#
zVfo@*ek^+?SvwhXOL&S%wBN^+i)@{xH$^BN7pGg%n?gQna^`sd%Zg;eTYOhH+@yiI
zE!bo$&BL|mgD`J0>>g|Dj*Vlvp+?ciOR^H(w@s`iTBE83-71&71UA&aC%NaY7<j-@
zlIA))e=(eh$?NxcYG}jd%$-f0tQ_E0_I3aOK`L}WTBYkP8Sbc$+Ho?`E919Ek5<(f
zR>@{07NwM>KTN?j6`Z{4Tkhz821nyw;%JFblUlQW>0swAaF5uhl?6N4aMZXkr$=%a
zUJnp9MGl7rH}os?viS+jCQ&3<y|8MZ@4boD@z`&&$E0IhdrrSSp+Ly;yvq})aBREO
zEyI-yw1uYP)+sKoO?HD~ls}m$$A}g66_C~$Nz=sN!>aRB-IZi^iaj!HY9MZ7w2Y;9
zOm+lX%s~v2|CLh+nQJRsK%oFm3`_vP#(E0C!9Z95OjSpy72whTU;qG9y73>Bhx`9r
XEN%cGySZ5AKccd{nq0Yz(bxY2;5`P=

literal 0
HcmV?d00001

diff --git a/extern/libpng/pngtrans.c b/extern/libpng/pngtrans.c
new file mode 100644
index 0000000000..1100f46ebe
--- /dev/null
+++ b/extern/libpng/pngtrans.c
@@ -0,0 +1,864 @@
+
+/* pngtrans.c - transforms the data in a row (used by both readers and writers)
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Turn on BGR-to-RGB mapping */
+void PNGAPI
+png_set_bgr(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_bgr");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_BGR;
+}
+#endif
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Turn on 16-bit byte swapping */
+void PNGAPI
+png_set_swap(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_swap");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (png_ptr->bit_depth == 16)
+      png_ptr->transformations |= PNG_SWAP_BYTES;
+}
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+/* Turn on pixel packing */
+void PNGAPI
+png_set_packing(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_packing");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (png_ptr->bit_depth < 8)
+   {
+      png_ptr->transformations |= PNG_PACK;
+#     ifdef PNG_WRITE_SUPPORTED
+         png_ptr->usr_bit_depth = 8;
+#     endif
+   }
+}
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+/* Turn on packed pixel swapping */
+void PNGAPI
+png_set_packswap(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_packswap");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (png_ptr->bit_depth < 8)
+      png_ptr->transformations |= PNG_PACKSWAP;
+}
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+void PNGAPI
+png_set_shift(png_structrp png_ptr, png_const_color_8p true_bits)
+{
+   png_debug(1, "in png_set_shift");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_SHIFT;
+   png_ptr->shift = *true_bits;
+}
+#endif
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+    defined(PNG_WRITE_INTERLACING_SUPPORTED)
+int PNGAPI
+png_set_interlace_handling(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_interlace handling");
+
+   if (png_ptr != 0 && png_ptr->interlaced != 0)
+   {
+      png_ptr->transformations |= PNG_INTERLACE;
+      return (7);
+   }
+
+   return (1);
+}
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+/* Add a filler byte on read, or remove a filler or alpha byte on write.
+ * The filler type has changed in v0.95 to allow future 2-byte fillers
+ * for 48-bit input data, as well as to avoid problems with some compilers
+ * that don't like bytes as parameters.
+ */
+void PNGAPI
+png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
+{
+   png_debug(1, "in png_set_filler");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* In libpng 1.6 it is possible to determine whether this is a read or write
+    * operation and therefore to do more checking here for a valid call.
+    */
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+   {
+#     ifdef PNG_READ_FILLER_SUPPORTED
+         /* On read png_set_filler is always valid, regardless of the base PNG
+          * format, because other transformations can give a format where the
+          * filler code can execute (basically an 8 or 16-bit component RGB or G
+          * format.)
+          *
+          * NOTE: usr_channels is not used by the read code!  (This has led to
+          * confusion in the past.)  The filler is only used in the read code.
+          */
+         png_ptr->filler = (png_uint_16)filler;
+#     else
+         png_app_error(png_ptr, "png_set_filler not supported on read");
+         PNG_UNUSED(filler) /* not used in the write case */
+         return;
+#     endif
+   }
+
+   else /* write */
+   {
+#     ifdef PNG_WRITE_FILLER_SUPPORTED
+         /* On write the usr_channels parameter must be set correctly at the
+          * start to record the number of channels in the app-supplied data.
+          */
+         switch (png_ptr->color_type)
+         {
+            case PNG_COLOR_TYPE_RGB:
+               png_ptr->usr_channels = 4;
+               break;
+
+            case PNG_COLOR_TYPE_GRAY:
+               if (png_ptr->bit_depth >= 8)
+               {
+                  png_ptr->usr_channels = 2;
+                  break;
+               }
+
+               else
+               {
+                  /* There simply isn't any code in libpng to strip out bits
+                   * from bytes when the components are less than a byte in
+                   * size!
+                   */
+                  png_app_error(png_ptr,
+                      "png_set_filler is invalid for"
+                      " low bit depth gray output");
+                  return;
+               }
+
+            default:
+               png_app_error(png_ptr,
+                   "png_set_filler: inappropriate color type");
+               return;
+         }
+#     else
+         png_app_error(png_ptr, "png_set_filler not supported on write");
+         return;
+#     endif
+   }
+
+   /* Here on success - libpng supports the operation, set the transformation
+    * and the flag to say where the filler channel is.
+    */
+   png_ptr->transformations |= PNG_FILLER;
+
+   if (filler_loc == PNG_FILLER_AFTER)
+      png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
+
+   else
+      png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
+}
+
+/* Added to libpng-1.2.7 */
+void PNGAPI
+png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
+{
+   png_debug(1, "in png_set_add_alpha");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_set_filler(png_ptr, filler, filler_loc);
+   /* The above may fail to do anything. */
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
+      png_ptr->transformations |= PNG_ADD_ALPHA;
+}
+
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_swap_alpha(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_swap_alpha");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_SWAP_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_invert_alpha(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_invert_alpha");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_INVERT_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+void PNGAPI
+png_set_invert_mono(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_invert_mono");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_INVERT_MONO;
+}
+
+/* Invert monochrome grayscale data */
+void /* PRIVATE */
+png_do_invert(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_invert");
+
+  /* This test removed from libpng version 1.0.13 and 1.2.0:
+   *   if (row_info->bit_depth == 1 &&
+   */
+   if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      png_bytep rp = row;
+      size_t i;
+      size_t istop = row_info->rowbytes;
+
+      for (i = 0; i < istop; i++)
+      {
+         *rp = (png_byte)(~(*rp));
+         rp++;
+      }
+   }
+
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+      row_info->bit_depth == 8)
+   {
+      png_bytep rp = row;
+      size_t i;
+      size_t istop = row_info->rowbytes;
+
+      for (i = 0; i < istop; i += 2)
+      {
+         *rp = (png_byte)(~(*rp));
+         rp += 2;
+      }
+   }
+
+#ifdef PNG_16BIT_SUPPORTED
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+      row_info->bit_depth == 16)
+   {
+      png_bytep rp = row;
+      size_t i;
+      size_t istop = row_info->rowbytes;
+
+      for (i = 0; i < istop; i += 4)
+      {
+         *rp = (png_byte)(~(*rp));
+         *(rp + 1) = (png_byte)(~(*(rp + 1)));
+         rp += 4;
+      }
+   }
+#endif
+}
+#endif
+
+#ifdef PNG_16BIT_SUPPORTED
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Swaps byte order on 16-bit depth images */
+void /* PRIVATE */
+png_do_swap(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_swap");
+
+   if (row_info->bit_depth == 16)
+   {
+      png_bytep rp = row;
+      png_uint_32 i;
+      png_uint_32 istop= row_info->width * row_info->channels;
+
+      for (i = 0; i < istop; i++, rp += 2)
+      {
+#ifdef PNG_BUILTIN_BSWAP16_SUPPORTED
+         /* Feature added to libpng-1.6.11 for testing purposes, not
+          * enabled by default.
+          */
+         *(png_uint_16*)rp = __builtin_bswap16(*(png_uint_16*)rp);
+#else
+         png_byte t = *rp;
+         *rp = *(rp + 1);
+         *(rp + 1) = t;
+#endif
+      }
+   }
+}
+#endif
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+static const png_byte onebppswaptable[256] = {
+   0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
+   0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
+   0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
+   0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
+   0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
+   0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
+   0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
+   0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
+   0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
+   0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
+   0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
+   0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
+   0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
+   0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
+   0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
+   0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
+   0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
+   0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
+   0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
+   0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
+   0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
+   0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
+   0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
+   0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
+   0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
+   0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
+   0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
+   0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
+   0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
+   0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
+   0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
+   0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
+};
+
+static const png_byte twobppswaptable[256] = {
+   0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
+   0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
+   0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
+   0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
+   0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
+   0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
+   0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
+   0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
+   0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
+   0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
+   0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
+   0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
+   0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
+   0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
+   0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
+   0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
+   0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
+   0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
+   0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
+   0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
+   0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
+   0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
+   0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
+   0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
+   0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
+   0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
+   0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
+   0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
+   0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
+   0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
+   0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
+   0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
+};
+
+static const png_byte fourbppswaptable[256] = {
+   0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
+   0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
+   0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
+   0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
+   0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
+   0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
+   0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
+   0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
+   0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
+   0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
+   0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
+   0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
+   0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
+   0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
+   0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
+   0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
+   0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
+   0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
+   0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
+   0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
+   0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
+   0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
+   0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
+   0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
+   0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
+   0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
+   0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
+   0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
+   0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
+   0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
+   0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
+   0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
+};
+
+/* Swaps pixel packing order within bytes */
+void /* PRIVATE */
+png_do_packswap(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_packswap");
+
+   if (row_info->bit_depth < 8)
+   {
+      png_bytep rp;
+      png_const_bytep end, table;
+
+      end = row + row_info->rowbytes;
+
+      if (row_info->bit_depth == 1)
+         table = onebppswaptable;
+
+      else if (row_info->bit_depth == 2)
+         table = twobppswaptable;
+
+      else if (row_info->bit_depth == 4)
+         table = fourbppswaptable;
+
+      else
+         return;
+
+      for (rp = row; rp < end; rp++)
+         *rp = table[*rp];
+   }
+}
+#endif /* PACKSWAP || WRITE_PACKSWAP */
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+/* Remove a channel - this used to be 'png_do_strip_filler' but it used a
+ * somewhat weird combination of flags to determine what to do.  All the calls
+ * to png_do_strip_filler are changed in 1.5.2 to call this instead with the
+ * correct arguments.
+ *
+ * The routine isn't general - the channel must be the channel at the start or
+ * end (not in the middle) of each pixel.
+ */
+void /* PRIVATE */
+png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
+{
+   png_bytep sp = row; /* source pointer */
+   png_bytep dp = row; /* destination pointer */
+   png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */
+
+   /* At the start sp will point to the first byte to copy and dp to where
+    * it is copied to.  ep always points just beyond the end of the row, so
+    * the loop simply copies (channels-1) channels until sp reaches ep.
+    *
+    * at_start:        0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
+    *            nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
+    */
+
+   /* GA, GX, XG cases */
+   if (row_info->channels == 2)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         if (at_start != 0) /* Skip initial filler */
+            ++sp;
+         else          /* Skip initial channel and, for sp, the filler */
+         {
+            sp += 2; ++dp;
+         }
+
+         /* For a 1 pixel wide image there is nothing to do */
+         while (sp < ep)
+         {
+            *dp++ = *sp; sp += 2;
+         }
+
+         row_info->pixel_depth = 8;
+      }
+
+      else if (row_info->bit_depth == 16)
+      {
+         if (at_start != 0) /* Skip initial filler */
+            sp += 2;
+         else          /* Skip initial channel and, for sp, the filler */
+         {
+            sp += 4; dp += 2;
+         }
+
+         while (sp < ep)
+         {
+            *dp++ = *sp++; *dp++ = *sp; sp += 3;
+         }
+
+         row_info->pixel_depth = 16;
+      }
+
+      else
+         return; /* bad bit depth */
+
+      row_info->channels = 1;
+
+      /* Finally fix the color type if it records an alpha channel */
+      if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+         row_info->color_type = PNG_COLOR_TYPE_GRAY;
+   }
+
+   /* RGBA, RGBX, XRGB cases */
+   else if (row_info->channels == 4)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         if (at_start != 0) /* Skip initial filler */
+            ++sp;
+         else          /* Skip initial channels and, for sp, the filler */
+         {
+            sp += 4; dp += 3;
+         }
+
+         /* Note that the loop adds 3 to dp and 4 to sp each time. */
+         while (sp < ep)
+         {
+            *dp++ = *sp++; *dp++ = *sp++; *dp++ = *sp; sp += 2;
+         }
+
+         row_info->pixel_depth = 24;
+      }
+
+      else if (row_info->bit_depth == 16)
+      {
+         if (at_start != 0) /* Skip initial filler */
+            sp += 2;
+         else          /* Skip initial channels and, for sp, the filler */
+         {
+            sp += 8; dp += 6;
+         }
+
+         while (sp < ep)
+         {
+            /* Copy 6 bytes, skip 2 */
+            *dp++ = *sp++; *dp++ = *sp++;
+            *dp++ = *sp++; *dp++ = *sp++;
+            *dp++ = *sp++; *dp++ = *sp; sp += 3;
+         }
+
+         row_info->pixel_depth = 48;
+      }
+
+      else
+         return; /* bad bit depth */
+
+      row_info->channels = 3;
+
+      /* Finally fix the color type if it records an alpha channel */
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         row_info->color_type = PNG_COLOR_TYPE_RGB;
+   }
+
+   else
+      return; /* The filler channel has gone already */
+
+   /* Fix the rowbytes value. */
+   row_info->rowbytes = (size_t)(dp-row);
+}
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Swaps red and blue bytes within a pixel */
+void /* PRIVATE */
+png_do_bgr(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_bgr");
+
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_uint_32 row_width = row_info->width;
+      if (row_info->bit_depth == 8)
+      {
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 3)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 2);
+               *(rp + 2) = save;
+            }
+         }
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 4)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 2);
+               *(rp + 2) = save;
+            }
+         }
+      }
+
+#ifdef PNG_16BIT_SUPPORTED
+      else if (row_info->bit_depth == 16)
+      {
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 6)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 4);
+               *(rp + 4) = save;
+               save = *(rp + 1);
+               *(rp + 1) = *(rp + 5);
+               *(rp + 5) = save;
+            }
+         }
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 8)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 4);
+               *(rp + 4) = save;
+               save = *(rp + 1);
+               *(rp + 1) = *(rp + 5);
+               *(rp + 5) = save;
+            }
+         }
+      }
+#endif
+   }
+}
+#endif /* READ_BGR || WRITE_BGR */
+
+#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
+    defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
+/* Added at libpng-1.5.10 */
+void /* PRIVATE */
+png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
+{
+   if (png_ptr->num_palette < (1 << row_info->bit_depth) &&
+      png_ptr->num_palette > 0) /* num_palette can be 0 in MNG files */
+   {
+      /* Calculations moved outside switch in an attempt to stop different
+       * compiler warnings.  'padding' is in *bits* within the last byte, it is
+       * an 'int' because pixel_depth becomes an 'int' in the expression below,
+       * and this calculation is used because it avoids warnings that other
+       * forms produced on either GCC or MSVC.
+       */
+      int padding = PNG_PADBITS(row_info->pixel_depth, row_info->width);
+      png_bytep rp = png_ptr->row_buf + row_info->rowbytes - 1;
+
+      switch (row_info->bit_depth)
+      {
+         case 1:
+         {
+            /* in this case, all bytes must be 0 so we don't need
+             * to unpack the pixels except for the rightmost one.
+             */
+            for (; rp > png_ptr->row_buf; rp--)
+            {
+              if ((*rp >> padding) != 0)
+                 png_ptr->num_palette_max = 1;
+              padding = 0;
+            }
+
+            break;
+         }
+
+         case 2:
+         {
+            for (; rp > png_ptr->row_buf; rp--)
+            {
+              int i = ((*rp >> padding) & 0x03);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              i = (((*rp >> padding) >> 2) & 0x03);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              i = (((*rp >> padding) >> 4) & 0x03);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              i = (((*rp >> padding) >> 6) & 0x03);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              padding = 0;
+            }
+
+            break;
+         }
+
+         case 4:
+         {
+            for (; rp > png_ptr->row_buf; rp--)
+            {
+              int i = ((*rp >> padding) & 0x0f);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              i = (((*rp >> padding) >> 4) & 0x0f);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              padding = 0;
+            }
+
+            break;
+         }
+
+         case 8:
+         {
+            for (; rp > png_ptr->row_buf; rp--)
+            {
+               if (*rp > png_ptr->num_palette_max)
+                  png_ptr->num_palette_max = (int) *rp;
+            }
+
+            break;
+         }
+
+         default:
+            break;
+      }
+   }
+}
+#endif /* CHECK_FOR_INVALID_INDEX */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+void PNGAPI
+png_set_user_transform_info(png_structrp png_ptr, png_voidp
+   user_transform_ptr, int user_transform_depth, int user_transform_channels)
+{
+   png_debug(1, "in png_set_user_transform_info");
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+      (png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
+   {
+      png_app_error(png_ptr,
+          "info change after png_start_read_image or png_read_update_info");
+      return;
+   }
+#endif
+
+   png_ptr->user_transform_ptr = user_transform_ptr;
+   png_ptr->user_transform_depth = (png_byte)user_transform_depth;
+   png_ptr->user_transform_channels = (png_byte)user_transform_channels;
+}
+#endif
+
+/* This function returns a pointer to the user_transform_ptr associated with
+ * the user transform functions.  The application should free any memory
+ * associated with this pointer before png_write_destroy and png_read_destroy
+ * are called.
+ */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+png_voidp PNGAPI
+png_get_user_transform_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return (NULL);
+
+   return png_ptr->user_transform_ptr;
+}
+#endif
+
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+png_uint_32 PNGAPI
+png_get_current_row_number(png_const_structrp png_ptr)
+{
+   /* See the comments in png.h - this is the sub-image row when reading an
+    * interlaced image.
+    */
+   if (png_ptr != NULL)
+      return png_ptr->row_number;
+
+   return PNG_UINT_32_MAX; /* help the app not to fail silently */
+}
+
+png_byte PNGAPI
+png_get_current_pass_number(png_const_structrp png_ptr)
+{
+   if (png_ptr != NULL)
+      return png_ptr->pass;
+   return 8; /* invalid */
+}
+#endif /* USER_TRANSFORM_INFO */
+#endif /* READ_USER_TRANSFORM || WRITE_USER_TRANSFORM */
+#endif /* READ || WRITE */
diff --git a/extern/libpng/pngusr.dfa b/extern/libpng/pngusr.dfa
new file mode 100644
index 0000000000..83067c38c0
--- /dev/null
+++ b/extern/libpng/pngusr.dfa
@@ -0,0 +1,14 @@
+# pngusr.dfa
+#
+# Build time configuration of libpng
+#
+# Enter build configuration options in this file
+#
+# Security settings: by default these limits are unset, you can change them
+# here by entering the appropriate values as #defines preceded by '@' (to cause,
+# them to be passed through to the build of pnglibconf.h), for example:
+#
+# @# define PNG_USER_WIDTH_MAX 65535
+# @# define PNG_USER_HEIGHT_MAX 65535
+# @# define PNG_USER_CHUNK_CACHE_MAX 256
+# @# define PNG_USER_CHUNK_MALLOC_MAX 640000
diff --git a/extern/libpng/pngwio.c b/extern/libpng/pngwio.c
new file mode 100644
index 0000000000..10e919dd03
--- /dev/null
+++ b/extern/libpng/pngwio.c
@@ -0,0 +1,168 @@
+
+/* pngwio.c - functions for data output
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2014,2016,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all output.  Users who need
+ * special handling are expected to write functions that have the same
+ * arguments as these and perform similar functions, but that possibly
+ * use different output methods.  Note that you shouldn't change these
+ * functions, but rather write replacement functions and then change
+ * them at run time with png_set_write_fn(...).
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Write the data to whatever output you are using.  The default routine
+ * writes to a file pointer.  Note that this routine sometimes gets called
+ * with very small lengths, so you should implement some kind of simple
+ * buffering if you are using unbuffered writes.  This should never be asked
+ * to write more than 64K on a 16-bit machine.
+ */
+
+void /* PRIVATE */
+png_write_data(png_structrp png_ptr, png_const_bytep data, size_t length)
+{
+   /* NOTE: write_data_fn must not change the buffer! */
+   if (png_ptr->write_data_fn != NULL )
+      (*(png_ptr->write_data_fn))(png_ptr, png_constcast(png_bytep,data),
+          length);
+
+   else
+      png_error(png_ptr, "Call to NULL write function");
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+/* This is the function that does the actual writing of data.  If you are
+ * not writing to a standard C stream, you should create a replacement
+ * write_data function and use it at run time with png_set_write_fn(), rather
+ * than changing the library.
+ */
+void PNGCBAPI
+png_default_write_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check;
+
+   if (png_ptr == NULL)
+      return;
+
+   check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
+
+   if (check != length)
+      png_error(png_ptr, "Write Error");
+}
+#endif
+
+/* This function is called to output any data pending writing (normally
+ * to disk).  After png_flush is called, there should be no data pending
+ * writing in any buffers.
+ */
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+void /* PRIVATE */
+png_flush(png_structrp png_ptr)
+{
+   if (png_ptr->output_flush_fn != NULL)
+      (*(png_ptr->output_flush_fn))(png_ptr);
+}
+
+#  ifdef PNG_STDIO_SUPPORTED
+void PNGCBAPI
+png_default_flush(png_structp png_ptr)
+{
+   png_FILE_p io_ptr;
+
+   if (png_ptr == NULL)
+      return;
+
+   io_ptr = png_voidcast(png_FILE_p, (png_ptr->io_ptr));
+   fflush(io_ptr);
+}
+#  endif
+#endif
+
+/* This function allows the application to supply new output functions for
+ * libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ * png_ptr       - pointer to a png output data structure
+ * io_ptr        - pointer to user supplied structure containing info about
+ *                 the output functions.  May be NULL.
+ * write_data_fn - pointer to a new output function that takes as its
+ *                 arguments a pointer to a png_struct, a pointer to
+ *                 data to be written, and a 32-bit unsigned int that is
+ *                 the number of bytes to be written.  The new write
+ *                 function should call png_error(png_ptr, "Error msg")
+ *                 to exit and output any fatal error messages.  May be
+ *                 NULL, in which case libpng's default function will
+ *                 be used.
+ * flush_data_fn - pointer to a new flush function that takes as its
+ *                 arguments a pointer to a png_struct.  After a call to
+ *                 the flush function, there should be no data in any buffers
+ *                 or pending transmission.  If the output method doesn't do
+ *                 any buffering of output, a function prototype must still be
+ *                 supplied although it doesn't have to do anything.  If
+ *                 PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
+ *                 time, output_flush_fn will be ignored, although it must be
+ *                 supplied for compatibility.  May be NULL, in which case
+ *                 libpng's default function will be used, if
+ *                 PNG_WRITE_FLUSH_SUPPORTED is defined.  This is not
+ *                 a good idea if io_ptr does not point to a standard
+ *                 *FILE structure.
+ */
+void PNGAPI
+png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr,
+    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->io_ptr = io_ptr;
+
+#ifdef PNG_STDIO_SUPPORTED
+   if (write_data_fn != NULL)
+      png_ptr->write_data_fn = write_data_fn;
+
+   else
+      png_ptr->write_data_fn = png_default_write_data;
+#else
+   png_ptr->write_data_fn = write_data_fn;
+#endif
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+#  ifdef PNG_STDIO_SUPPORTED
+
+   if (output_flush_fn != NULL)
+      png_ptr->output_flush_fn = output_flush_fn;
+
+   else
+      png_ptr->output_flush_fn = png_default_flush;
+
+#  else
+   png_ptr->output_flush_fn = output_flush_fn;
+#  endif
+#else
+   PNG_UNUSED(output_flush_fn)
+#endif /* WRITE_FLUSH */
+
+#ifdef PNG_READ_SUPPORTED
+   /* It is an error to read while writing a png file */
+   if (png_ptr->read_data_fn != NULL)
+   {
+      png_ptr->read_data_fn = NULL;
+
+      png_warning(png_ptr,
+          "Can't set both read_data_fn and write_data_fn in the"
+          " same structure");
+   }
+#endif
+}
+#endif /* WRITE */
diff --git a/extern/libpng/pngwrite.c b/extern/libpng/pngwrite.c
new file mode 100644
index 0000000000..59377a4dde
--- /dev/null
+++ b/extern/libpng/pngwrite.c
@@ -0,0 +1,2395 @@
+
+/* pngwrite.c - general routines to write a PNG file
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+#  include <errno.h>
+#endif /* SIMPLIFIED_WRITE_STDIO */
+
+#ifdef PNG_WRITE_SUPPORTED
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+/* Write out all the unknown chunks for the current given location */
+static void
+write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
+    unsigned int where)
+{
+   if (info_ptr->unknown_chunks_num != 0)
+   {
+      png_const_unknown_chunkp up;
+
+      png_debug(5, "writing extra chunks");
+
+      for (up = info_ptr->unknown_chunks;
+           up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
+           ++up)
+         if ((up->location & where) != 0)
+      {
+         /* If per-chunk unknown chunk handling is enabled use it, otherwise
+          * just write the chunks the application has set.
+          */
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+         int keep = png_handle_as_unknown(png_ptr, up->name);
+
+         /* NOTE: this code is radically different from the read side in the
+          * matter of handling an ancillary unknown chunk.  In the read side
+          * the default behavior is to discard it, in the code below the default
+          * behavior is to write it.  Critical chunks are, however, only
+          * written if explicitly listed or if the default is set to write all
+          * unknown chunks.
+          *
+          * The default handling is also slightly weird - it is not possible to
+          * stop the writing of all unsafe-to-copy chunks!
+          *
+          * TODO: REVIEW: this would seem to be a bug.
+          */
+         if (keep != PNG_HANDLE_CHUNK_NEVER &&
+             ((up->name[3] & 0x20) /* safe-to-copy overrides everything */ ||
+              keep == PNG_HANDLE_CHUNK_ALWAYS ||
+              (keep == PNG_HANDLE_CHUNK_AS_DEFAULT &&
+               png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS)))
+#endif
+         {
+            /* TODO: review, what is wrong with a zero length unknown chunk? */
+            if (up->size == 0)
+               png_warning(png_ptr, "Writing zero-length unknown chunk");
+
+            png_write_chunk(png_ptr, up->name, up->data, up->size);
+         }
+      }
+   }
+}
+#endif /* WRITE_UNKNOWN_CHUNKS */
+
+/* Writes all the PNG information.  This is the suggested way to use the
+ * library.  If you have a new chunk to add, make a function to write it,
+ * and put it in the correct location here.  If you want the chunk written
+ * after the image data, put it in png_write_end().  I strongly encourage
+ * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
+ * the chunk, as that will keep the code from breaking if you want to just
+ * write a plain PNG file.  If you have long comments, I suggest writing
+ * them in png_write_end(), and compressing them.
+ */
+void PNGAPI
+png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
+{
+   png_debug(1, "in png_write_info_before_PLTE");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
+   {
+      /* Write PNG signature */
+      png_write_sig(png_ptr);
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+      if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
+          png_ptr->mng_features_permitted != 0)
+      {
+         png_warning(png_ptr,
+             "MNG features are not allowed in a PNG datastream");
+         png_ptr->mng_features_permitted = 0;
+      }
+#endif
+
+      /* Write IHDR information. */
+      png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
+          info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
+          info_ptr->filter_type,
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+          info_ptr->interlace_type
+#else
+          0
+#endif
+         );
+
+      /* The rest of these check to see if the valid field has the appropriate
+       * flag set, and if it does, writes the chunk.
+       *
+       * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
+       * the chunks will be written if the WRITE routine is there and
+       * information * is available in the COLORSPACE. (See
+       * png_colorspace_sync_info in png.c for where the valid flags get set.)
+       *
+       * Under certain circumstances the colorspace can be invalidated without
+       * syncing the info_struct 'valid' flags; this happens if libpng detects
+       * an error and calls png_error while the color space is being set, yet
+       * the application continues writing the PNG.  So check the 'invalid'
+       * flag here too.
+       */
+#ifdef PNG_GAMMA_SUPPORTED
+#  ifdef PNG_WRITE_gAMA_SUPPORTED
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
+          (info_ptr->valid & PNG_INFO_gAMA) != 0)
+         png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
+#  endif
+#endif
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+      /* Write only one of sRGB or an ICC profile.  If a profile was supplied
+       * and it matches one of the known sRGB ones issue a warning.
+       */
+#  ifdef PNG_WRITE_iCCP_SUPPORTED
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+             (info_ptr->valid & PNG_INFO_iCCP) != 0)
+         {
+#    ifdef PNG_WRITE_sRGB_SUPPORTED
+               if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
+                  png_app_warning(png_ptr,
+                      "profile matches sRGB but writing iCCP instead");
+#     endif
+
+            png_write_iCCP(png_ptr, info_ptr->iccp_name,
+                info_ptr->iccp_profile);
+         }
+#     ifdef PNG_WRITE_sRGB_SUPPORTED
+         else
+#     endif
+#  endif
+
+#  ifdef PNG_WRITE_sRGB_SUPPORTED
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+             (info_ptr->valid & PNG_INFO_sRGB) != 0)
+            png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
+#  endif /* WRITE_sRGB */
+#endif /* COLORSPACE */
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+         if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+            png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
+#endif
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+#  ifdef PNG_WRITE_cHRM_SUPPORTED
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+             (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
+             (info_ptr->valid & PNG_INFO_cHRM) != 0)
+            png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
+#  endif
+#endif
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+         write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
+#endif
+
+      png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
+   }
+}
+
+void PNGAPI
+png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
+{
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+   int i;
+#endif
+
+   png_debug(1, "in png_write_info");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_write_info_before_PLTE(png_ptr, info_ptr);
+
+   if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
+      png_write_PLTE(png_ptr, info_ptr->palette,
+          (png_uint_32)info_ptr->num_palette);
+
+   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      png_error(png_ptr, "Valid palette required for paletted images");
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
+   {
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+      /* Invert the alpha channel (in tRNS) */
+      if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
+          info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         int j, jend;
+
+         jend = info_ptr->num_trans;
+         if (jend > PNG_MAX_PALETTE_LENGTH)
+            jend = PNG_MAX_PALETTE_LENGTH;
+
+         for (j = 0; j<jend; ++j)
+            info_ptr->trans_alpha[j] =
+               (png_byte)(255 - info_ptr->trans_alpha[j]);
+      }
+#endif
+      png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
+          info_ptr->num_trans, info_ptr->color_type);
+   }
+#endif
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
+      png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
+#endif
+
+#ifdef PNG_WRITE_eXIf_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
+      png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_hIST) != 0)
+      png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
+      png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
+          info_ptr->offset_unit_type);
+#endif
+
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
+      png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
+          info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
+          info_ptr->pcal_units, info_ptr->pcal_params);
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
+      png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
+          info_ptr->scal_s_width, info_ptr->scal_s_height);
+#endif /* sCAL */
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
+      png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
+          info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
+#endif /* pHYs */
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_tIME) != 0)
+   {
+      png_write_tIME(png_ptr, &(info_ptr->mod_time));
+      png_ptr->mode |= PNG_WROTE_tIME;
+   }
+#endif /* tIME */
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
+      for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
+         png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
+#endif /* sPLT */
+
+#ifdef PNG_WRITE_TEXT_SUPPORTED
+   /* Check to see if we need to write text chunks */
+   for (i = 0; i < info_ptr->num_text; i++)
+   {
+      png_debug2(2, "Writing header text chunk %d, type %d", i,
+          info_ptr->text[i].compression);
+      /* An internationalized chunk? */
+      if (info_ptr->text[i].compression > 0)
+      {
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+         /* Write international chunk */
+         png_write_iTXt(png_ptr,
+             info_ptr->text[i].compression,
+             info_ptr->text[i].key,
+             info_ptr->text[i].lang,
+             info_ptr->text[i].lang_key,
+             info_ptr->text[i].text);
+         /* Mark this chunk as written */
+         if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+         else
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+         png_warning(png_ptr, "Unable to write international text");
+#endif
+      }
+
+      /* If we want a compressed text chunk */
+      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
+      {
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+         /* Write compressed chunk */
+         png_write_zTXt(png_ptr, info_ptr->text[i].key,
+             info_ptr->text[i].text, info_ptr->text[i].compression);
+         /* Mark this chunk as written */
+         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+         png_warning(png_ptr, "Unable to write compressed text");
+#endif
+      }
+
+      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+      {
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+         /* Write uncompressed chunk */
+         png_write_tEXt(png_ptr, info_ptr->text[i].key,
+             info_ptr->text[i].text,
+             0);
+         /* Mark this chunk as written */
+         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+#else
+         /* Can't get here */
+         png_warning(png_ptr, "Unable to write uncompressed text");
+#endif
+      }
+   }
+#endif /* tEXt */
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+   write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
+#endif
+}
+
+/* Writes the end of the PNG file.  If you don't want to write comments or
+ * time information, you can pass NULL for info.  If you already wrote these
+ * in png_write_info(), do not write them again here.  If you have long
+ * comments, I suggest writing them here, and compressing them.
+ */
+void PNGAPI
+png_write_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+   png_debug(1, "in png_write_end");
+
+   if (png_ptr == NULL)
+      return;
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+      png_error(png_ptr, "No IDATs written into file");
+
+#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   if (png_ptr->num_palette_max > png_ptr->num_palette)
+      png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
+#endif
+
+   /* See if user wants us to write information chunks */
+   if (info_ptr != NULL)
+   {
+#ifdef PNG_WRITE_TEXT_SUPPORTED
+      int i; /* local index variable */
+#endif
+#ifdef PNG_WRITE_tIME_SUPPORTED
+      /* Check to see if user has supplied a time chunk */
+      if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
+          (png_ptr->mode & PNG_WROTE_tIME) == 0)
+         png_write_tIME(png_ptr, &(info_ptr->mod_time));
+
+#endif
+#ifdef PNG_WRITE_TEXT_SUPPORTED
+      /* Loop through comment chunks */
+      for (i = 0; i < info_ptr->num_text; i++)
+      {
+         png_debug2(2, "Writing trailer text chunk %d, type %d", i,
+             info_ptr->text[i].compression);
+         /* An internationalized chunk? */
+         if (info_ptr->text[i].compression > 0)
+         {
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+            /* Write international chunk */
+            png_write_iTXt(png_ptr,
+                info_ptr->text[i].compression,
+                info_ptr->text[i].key,
+                info_ptr->text[i].lang,
+                info_ptr->text[i].lang_key,
+                info_ptr->text[i].text);
+            /* Mark this chunk as written */
+            if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+            else
+               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+            png_warning(png_ptr, "Unable to write international text");
+#endif
+         }
+
+         else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
+         {
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+            /* Write compressed chunk */
+            png_write_zTXt(png_ptr, info_ptr->text[i].key,
+                info_ptr->text[i].text, info_ptr->text[i].compression);
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+            png_warning(png_ptr, "Unable to write compressed text");
+#endif
+         }
+
+         else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+         {
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+            /* Write uncompressed chunk */
+            png_write_tEXt(png_ptr, info_ptr->text[i].key,
+                info_ptr->text[i].text, 0);
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+#else
+            png_warning(png_ptr, "Unable to write uncompressed text");
+#endif
+         }
+      }
+#endif
+
+#ifdef PNG_WRITE_eXIf_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
+      png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
+#endif
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+      write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
+#endif
+   }
+
+   png_ptr->mode |= PNG_AFTER_IDAT;
+
+   /* Write end of PNG file */
+   png_write_IEND(png_ptr);
+
+   /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
+    * and restored again in libpng-1.2.30, may cause some applications that
+    * do not set png_ptr->output_flush_fn to crash.  If your application
+    * experiences a problem, please try building libpng with
+    * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
+    * png-mng-implement at lists.sf.net .
+    */
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+#  ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
+   png_flush(png_ptr);
+#  endif
+#endif
+}
+
+#ifdef PNG_CONVERT_tIME_SUPPORTED
+void PNGAPI
+png_convert_from_struct_tm(png_timep ptime, const struct tm * ttime)
+{
+   png_debug(1, "in png_convert_from_struct_tm");
+
+   ptime->year = (png_uint_16)(1900 + ttime->tm_year);
+   ptime->month = (png_byte)(ttime->tm_mon + 1);
+   ptime->day = (png_byte)ttime->tm_mday;
+   ptime->hour = (png_byte)ttime->tm_hour;
+   ptime->minute = (png_byte)ttime->tm_min;
+   ptime->second = (png_byte)ttime->tm_sec;
+}
+
+void PNGAPI
+png_convert_from_time_t(png_timep ptime, time_t ttime)
+{
+   struct tm *tbuf;
+
+   png_debug(1, "in png_convert_from_time_t");
+
+   tbuf = gmtime(&ttime);
+   png_convert_from_struct_tm(ptime, tbuf);
+}
+#endif
+
+/* Initialize png_ptr structure, and allocate any memory needed */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
+{
+#ifndef PNG_USER_MEM_SUPPORTED
+   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+       error_fn, warn_fn, NULL, NULL, NULL);
+#else
+   return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
+       warn_fn, NULL, NULL, NULL);
+}
+
+/* Alternate initialize png_ptr structure, and allocate any memory needed */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
+{
+   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+       error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
+#endif /* USER_MEM */
+   if (png_ptr != NULL)
+   {
+      /* Set the zlib control values to defaults; they can be overridden by the
+       * application after the struct has been created.
+       */
+      png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
+
+      /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
+       * pngwutil.c defaults it according to whether or not filters will be
+       * used, and ignores this setting.
+       */
+      png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
+      png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
+      png_ptr->zlib_mem_level = 8;
+      png_ptr->zlib_window_bits = 15;
+      png_ptr->zlib_method = 8;
+
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+      png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
+      png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
+      png_ptr->zlib_text_mem_level = 8;
+      png_ptr->zlib_text_window_bits = 15;
+      png_ptr->zlib_text_method = 8;
+#endif /* WRITE_COMPRESSED_TEXT */
+
+      /* This is a highly dubious configuration option; by default it is off,
+       * but it may be appropriate for private builds that are testing
+       * extensions not conformant to the current specification, or of
+       * applications that must not fail to write at all costs!
+       */
+#ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
+      /* In stable builds only warn if an application error can be completely
+       * handled.
+       */
+      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
+#endif
+
+      /* App warnings are warnings in release (or release candidate) builds but
+       * are errors during development.
+       */
+#if PNG_RELEASE_BUILD
+      png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
+#endif
+
+      /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
+       * do it itself) avoiding setting the default function if it is not
+       * required.
+       */
+      png_set_write_fn(png_ptr, NULL, NULL, NULL);
+   }
+
+   return png_ptr;
+}
+
+
+/* Write a few rows of image data.  If the image is interlaced,
+ * either you will have to write the 7 sub images, or, if you
+ * have called png_set_interlace_handling(), you will have to
+ * "write" the image seven times.
+ */
+void PNGAPI
+png_write_rows(png_structrp png_ptr, png_bytepp row,
+    png_uint_32 num_rows)
+{
+   png_uint_32 i; /* row counter */
+   png_bytepp rp; /* row pointer */
+
+   png_debug(1, "in png_write_rows");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* Loop through the rows */
+   for (i = 0, rp = row; i < num_rows; i++, rp++)
+   {
+      png_write_row(png_ptr, *rp);
+   }
+}
+
+/* Write the image.  You only need to call this function once, even
+ * if you are writing an interlaced image.
+ */
+void PNGAPI
+png_write_image(png_structrp png_ptr, png_bytepp image)
+{
+   png_uint_32 i; /* row index */
+   int pass, num_pass; /* pass variables */
+   png_bytepp rp; /* points to current row */
+
+   if (png_ptr == NULL)
+      return;
+
+   png_debug(1, "in png_write_image");
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* Initialize interlace handling.  If image is not interlaced,
+    * this will set pass to 1
+    */
+   num_pass = png_set_interlace_handling(png_ptr);
+#else
+   num_pass = 1;
+#endif
+   /* Loop through passes */
+   for (pass = 0; pass < num_pass; pass++)
+   {
+      /* Loop through image */
+      for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
+      {
+         png_write_row(png_ptr, *rp);
+      }
+   }
+}
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Performs intrapixel differencing  */
+static void
+png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_intrapixel");
+
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      int bytes_per_pixel;
+      png_uint_32 row_width = row_info->width;
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 3;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 4;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            *(rp)     = (png_byte)(*rp       - *(rp + 1));
+            *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
+         }
+      }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+      else if (row_info->bit_depth == 16)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 6;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 8;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            png_uint_32 s0   = (png_uint_32)(*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 red  = (png_uint_32)((s0 - s1) & 0xffffL);
+            png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
+            *(rp    ) = (png_byte)(red >> 8);
+            *(rp + 1) = (png_byte)red;
+            *(rp + 4) = (png_byte)(blue >> 8);
+            *(rp + 5) = (png_byte)blue;
+         }
+      }
+#endif /* WRITE_16BIT */
+   }
+}
+#endif /* MNG_FEATURES */
+
+/* Called by user to write a row of image data */
+void PNGAPI
+png_write_row(png_structrp png_ptr, png_const_bytep row)
+{
+   /* 1.5.6: moved from png_struct to be a local structure: */
+   png_row_info row_info;
+
+   if (png_ptr == NULL)
+      return;
+
+   png_debug2(1, "in png_write_row (row %u, pass %d)",
+       png_ptr->row_number, png_ptr->pass);
+
+   /* Initialize transformations and other stuff if first time */
+   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
+   {
+      /* Make sure we wrote the header info */
+      if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
+         png_error(png_ptr,
+             "png_write_info was never called before png_write_row");
+
+      /* Check for transforms that have been set but were defined out */
+#if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
+      if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+         png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
+      if ((png_ptr->transformations & PNG_FILLER) != 0)
+         png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
+#endif
+#if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
+    defined(PNG_READ_PACKSWAP_SUPPORTED)
+      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+         png_warning(png_ptr,
+             "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
+      if ((png_ptr->transformations & PNG_PACK) != 0)
+         png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
+      if ((png_ptr->transformations & PNG_SHIFT) != 0)
+         png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
+      if ((png_ptr->transformations & PNG_BGR) != 0)
+         png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
+      if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+         png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
+#endif
+
+      png_write_start_row(png_ptr);
+   }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* If interlaced and not interested in row, return */
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      switch (png_ptr->pass)
+      {
+         case 0:
+            if ((png_ptr->row_number & 0x07) != 0)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 1:
+            if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 2:
+            if ((png_ptr->row_number & 0x07) != 4)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 3:
+            if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 4:
+            if ((png_ptr->row_number & 0x03) != 2)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 5:
+            if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 6:
+            if ((png_ptr->row_number & 0x01) == 0)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         default: /* error: ignore it */
+            break;
+      }
+   }
+#endif
+
+   /* Set up row info for transformations */
+   row_info.color_type = png_ptr->color_type;
+   row_info.width = png_ptr->usr_width;
+   row_info.channels = png_ptr->usr_channels;
+   row_info.bit_depth = png_ptr->usr_bit_depth;
+   row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
+   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+   png_debug1(3, "row_info->color_type = %d", row_info.color_type);
+   png_debug1(3, "row_info->width = %u", row_info.width);
+   png_debug1(3, "row_info->channels = %d", row_info.channels);
+   png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
+   png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
+   png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
+
+   /* Copy user's row into buffer, leaving room for filter byte. */
+   memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* Handle interlacing */
+   if (png_ptr->interlaced && png_ptr->pass < 6 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
+      /* This should always get caught above, but still ... */
+      if (row_info.width == 0)
+      {
+         png_write_finish_row(png_ptr);
+         return;
+      }
+   }
+#endif
+
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+   /* Handle other transformations */
+   if (png_ptr->transformations != 0)
+      png_do_write_transformations(png_ptr, &row_info);
+#endif
+
+   /* At this point the row_info pixel depth must match the 'transformed' depth,
+    * which is also the output depth.
+    */
+   if (row_info.pixel_depth != png_ptr->pixel_depth ||
+       row_info.pixel_depth != png_ptr->transformed_pixel_depth)
+      png_error(png_ptr, "internal write transform logic error");
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   /* Write filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not write a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
+   {
+      /* Intrapixel differencing */
+      png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
+   }
+#endif
+
+/* Added at libpng-1.5.10 */
+#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   /* Check for out-of-range palette index */
+   if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
+       png_ptr->num_palette_max >= 0)
+      png_do_check_palette_indexes(png_ptr, &row_info);
+#endif
+
+   /* Find a filter if necessary, filter the row and write it out. */
+   png_write_find_filter(png_ptr, &row_info);
+
+   if (png_ptr->write_row_fn != NULL)
+      (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
+}
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+/* Set the automatic flush interval or 0 to turn flushing off */
+void PNGAPI
+png_set_flush(png_structrp png_ptr, int nrows)
+{
+   png_debug(1, "in png_set_flush");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows);
+}
+
+/* Flush the current output buffers now */
+void PNGAPI
+png_write_flush(png_structrp png_ptr)
+{
+   png_debug(1, "in png_write_flush");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* We have already written out all of the data */
+   if (png_ptr->row_number >= png_ptr->num_rows)
+      return;
+
+   png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
+   png_ptr->flush_rows = 0;
+   png_flush(png_ptr);
+}
+#endif /* WRITE_FLUSH */
+
+/* Free any memory used in png_ptr struct without freeing the struct itself. */
+static void
+png_write_destroy(png_structrp png_ptr)
+{
+   png_debug(1, "in png_write_destroy");
+
+   /* Free any memory zlib uses */
+   if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+      deflateEnd(&png_ptr->zstream);
+
+   /* Free our memory.  png_free checks NULL for us. */
+   png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
+   png_free(png_ptr, png_ptr->row_buf);
+   png_ptr->row_buf = NULL;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   png_free(png_ptr, png_ptr->prev_row);
+   png_free(png_ptr, png_ptr->try_row);
+   png_free(png_ptr, png_ptr->tst_row);
+   png_ptr->prev_row = NULL;
+   png_ptr->try_row = NULL;
+   png_ptr->tst_row = NULL;
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   png_free(png_ptr, png_ptr->chunk_list);
+   png_ptr->chunk_list = NULL;
+#endif
+
+   /* The error handling and memory handling information is left intact at this
+    * point: the jmp_buf may still have to be freed.  See png_destroy_png_struct
+    * for how this happens.
+    */
+}
+
+/* Free all memory used by the write.
+ * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
+ * *png_ptr_ptr.  Prior to 1.6.0 it would accept such a value and it would free
+ * the passed in info_structs but it would quietly fail to free any of the data
+ * inside them.  In 1.6.0 it quietly does nothing (it has to be quiet because it
+ * has no png_ptr.)
+ */
+void PNGAPI
+png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
+{
+   png_debug(1, "in png_destroy_write_struct");
+
+   if (png_ptr_ptr != NULL)
+   {
+      png_structrp png_ptr = *png_ptr_ptr;
+
+      if (png_ptr != NULL) /* added in libpng 1.6.0 */
+      {
+         png_destroy_info_struct(png_ptr, info_ptr_ptr);
+
+         *png_ptr_ptr = NULL;
+         png_write_destroy(png_ptr);
+         png_destroy_png_struct(png_ptr);
+      }
+   }
+}
+
+/* Allow the application to select one or more row filters to use. */
+void PNGAPI
+png_set_filter(png_structrp png_ptr, int method, int filters)
+{
+   png_debug(1, "in png_set_filter");
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       (method == PNG_INTRAPIXEL_DIFFERENCING))
+      method = PNG_FILTER_TYPE_BASE;
+
+#endif
+   if (method == PNG_FILTER_TYPE_BASE)
+   {
+      switch (filters & (PNG_ALL_FILTERS | 0x07))
+      {
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         case 5:
+         case 6:
+         case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
+#endif /* WRITE_FILTER */
+            /* FALLTHROUGH */
+         case PNG_FILTER_VALUE_NONE:
+            png_ptr->do_filter = PNG_FILTER_NONE; break;
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         case PNG_FILTER_VALUE_SUB:
+            png_ptr->do_filter = PNG_FILTER_SUB; break;
+
+         case PNG_FILTER_VALUE_UP:
+            png_ptr->do_filter = PNG_FILTER_UP; break;
+
+         case PNG_FILTER_VALUE_AVG:
+            png_ptr->do_filter = PNG_FILTER_AVG; break;
+
+         case PNG_FILTER_VALUE_PAETH:
+            png_ptr->do_filter = PNG_FILTER_PAETH; break;
+
+         default:
+            png_ptr->do_filter = (png_byte)filters; break;
+#else
+         default:
+            png_app_error(png_ptr, "Unknown row filter for method 0");
+#endif /* WRITE_FILTER */
+      }
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+      /* If we have allocated the row_buf, this means we have already started
+       * with the image and we should have allocated all of the filter buffers
+       * that have been selected.  If prev_row isn't already allocated, then
+       * it is too late to start using the filters that need it, since we
+       * will be missing the data in the previous row.  If an application
+       * wants to start and stop using particular filters during compression,
+       * it should start out with all of the filters, and then remove them
+       * or add them back after the start of compression.
+       *
+       * NOTE: this is a nasty constraint on the code, because it means that the
+       * prev_row buffer must be maintained even if there are currently no
+       * 'prev_row' requiring filters active.
+       */
+      if (png_ptr->row_buf != NULL)
+      {
+         int num_filters;
+         png_alloc_size_t buf_size;
+
+         /* Repeat the checks in png_write_start_row; 1 pixel high or wide
+          * images cannot benefit from certain filters.  If this isn't done here
+          * the check below will fire on 1 pixel high images.
+          */
+         if (png_ptr->height == 1)
+            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+         if (png_ptr->width == 1)
+            filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+         if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
+            && png_ptr->prev_row == NULL)
+         {
+            /* This is the error case, however it is benign - the previous row
+             * is not available so the filter can't be used.  Just warn here.
+             */
+            png_app_warning(png_ptr,
+                "png_set_filter: UP/AVG/PAETH cannot be added after start");
+            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+         }
+
+         num_filters = 0;
+
+         if (filters & PNG_FILTER_SUB)
+            num_filters++;
+
+         if (filters & PNG_FILTER_UP)
+            num_filters++;
+
+         if (filters & PNG_FILTER_AVG)
+            num_filters++;
+
+         if (filters & PNG_FILTER_PAETH)
+            num_filters++;
+
+         /* Allocate needed row buffers if they have not already been
+          * allocated.
+          */
+         buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
+             png_ptr->width) + 1;
+
+         if (png_ptr->try_row == NULL)
+            png_ptr->try_row = png_voidcast(png_bytep,
+                png_malloc(png_ptr, buf_size));
+
+         if (num_filters > 1)
+         {
+            if (png_ptr->tst_row == NULL)
+               png_ptr->tst_row = png_voidcast(png_bytep,
+                   png_malloc(png_ptr, buf_size));
+         }
+      }
+      png_ptr->do_filter = (png_byte)filters;
+#endif
+   }
+   else
+      png_error(png_ptr, "Unknown custom filter method");
+}
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
+/* Provide floating and fixed point APIs */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
+    int num_weights, png_const_doublep filter_weights,
+    png_const_doublep filter_costs)
+{
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(heuristic_method)
+   PNG_UNUSED(num_weights)
+   PNG_UNUSED(filter_weights)
+   PNG_UNUSED(filter_costs)
+}
+#endif /* FLOATING_POINT */
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
+    int num_weights, png_const_fixed_point_p filter_weights,
+    png_const_fixed_point_p filter_costs)
+{
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(heuristic_method)
+   PNG_UNUSED(num_weights)
+   PNG_UNUSED(filter_weights)
+   PNG_UNUSED(filter_costs)
+}
+#endif /* FIXED_POINT */
+#endif /* WRITE_WEIGHTED_FILTER */
+
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+void PNGAPI
+png_set_compression_level(png_structrp png_ptr, int level)
+{
+   png_debug(1, "in png_set_compression_level");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_level = level;
+}
+
+void PNGAPI
+png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
+{
+   png_debug(1, "in png_set_compression_mem_level");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_mem_level = mem_level;
+}
+
+void PNGAPI
+png_set_compression_strategy(png_structrp png_ptr, int strategy)
+{
+   png_debug(1, "in png_set_compression_strategy");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* The flag setting here prevents the libpng dynamic selection of strategy.
+    */
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
+   png_ptr->zlib_strategy = strategy;
+}
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+void PNGAPI
+png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
+{
+   if (png_ptr == NULL)
+      return;
+
+   /* Prior to 1.6.0 this would warn but then set the window_bits value. This
+    * meant that negative window bits values could be selected that would cause
+    * libpng to write a non-standard PNG file with raw deflate or gzip
+    * compressed IDAT or ancillary chunks.  Such files can be read and there is
+    * no warning on read, so this seems like a very bad idea.
+    */
+   if (window_bits > 15)
+   {
+      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
+      window_bits = 15;
+   }
+
+   else if (window_bits < 8)
+   {
+      png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
+      window_bits = 8;
+   }
+
+   png_ptr->zlib_window_bits = window_bits;
+}
+
+void PNGAPI
+png_set_compression_method(png_structrp png_ptr, int method)
+{
+   png_debug(1, "in png_set_compression_method");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* This would produce an invalid PNG file if it worked, but it doesn't and
+    * deflate will fault it, so it is harmless to just warn here.
+    */
+   if (method != 8)
+      png_warning(png_ptr, "Only compression method 8 is supported by PNG");
+
+   png_ptr->zlib_method = method;
+}
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+/* The following were added to libpng-1.5.4 */
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+void PNGAPI
+png_set_text_compression_level(png_structrp png_ptr, int level)
+{
+   png_debug(1, "in png_set_text_compression_level");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_text_level = level;
+}
+
+void PNGAPI
+png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
+{
+   png_debug(1, "in png_set_text_compression_mem_level");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_text_mem_level = mem_level;
+}
+
+void PNGAPI
+png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
+{
+   png_debug(1, "in png_set_text_compression_strategy");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_text_strategy = strategy;
+}
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+void PNGAPI
+png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
+{
+   if (png_ptr == NULL)
+      return;
+
+   if (window_bits > 15)
+   {
+      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
+      window_bits = 15;
+   }
+
+   else if (window_bits < 8)
+   {
+      png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
+      window_bits = 8;
+   }
+
+   png_ptr->zlib_text_window_bits = window_bits;
+}
+
+void PNGAPI
+png_set_text_compression_method(png_structrp png_ptr, int method)
+{
+   png_debug(1, "in png_set_text_compression_method");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (method != 8)
+      png_warning(png_ptr, "Only compression method 8 is supported by PNG");
+
+   png_ptr->zlib_text_method = method;
+}
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+/* end of API added to libpng-1.5.4 */
+
+void PNGAPI
+png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->write_row_fn = write_row_fn;
+}
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+void PNGAPI
+png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
+    write_user_transform_fn)
+{
+   png_debug(1, "in png_set_write_user_transform_fn");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_USER_TRANSFORM;
+   png_ptr->write_user_transform_fn = write_user_transform_fn;
+}
+#endif
+
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+void PNGAPI
+png_write_png(png_structrp png_ptr, png_inforp info_ptr,
+    int transforms, voidp params)
+{
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
+   {
+      png_app_error(png_ptr, "no rows for png_write_image to write");
+      return;
+   }
+
+   /* Write the file header information. */
+   png_write_info(png_ptr, info_ptr);
+
+   /* ------ these transformations don't touch the info structure ------- */
+
+   /* Invert monochrome pixels */
+   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+      png_set_invert_mono(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
+#endif
+
+   /* Shift the pixels up to a legal bit depth and fill in
+    * as appropriate to correctly scale the image.
+    */
+   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+         png_set_shift(png_ptr, &info_ptr->sig_bit);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
+#endif
+
+   /* Pack pixels into bytes */
+   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
+#ifdef PNG_WRITE_PACK_SUPPORTED
+      png_set_packing(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
+#endif
+
+   /* Swap location of alpha bytes from ARGB to RGBA */
+   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+      png_set_swap_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
+#endif
+
+   /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
+    * RGB, note that the code expects the input color type to be G or RGB; no
+    * alpha channel.
+    */
+   if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
+       PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
+   {
+#ifdef PNG_WRITE_FILLER_SUPPORTED
+      if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
+      {
+         if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+            png_app_error(png_ptr,
+                "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
+
+         /* Continue if ignored - this is the pre-1.6.10 behavior */
+         png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
+      }
+
+      else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+         png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
+#endif
+   }
+
+   /* Flip BGR pixels to RGB */
+   if ((transforms & PNG_TRANSFORM_BGR) != 0)
+#ifdef PNG_WRITE_BGR_SUPPORTED
+      png_set_bgr(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
+#endif
+
+   /* Swap bytes of 16-bit files to most significant byte first */
+   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
+#ifdef PNG_WRITE_SWAP_SUPPORTED
+      png_set_swap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
+#endif
+
+   /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
+   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+      png_set_packswap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
+#endif
+
+   /* Invert the alpha channel from opacity to transparency */
+   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+      png_set_invert_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
+#endif
+
+   /* ----------------------- end of transformations ------------------- */
+
+   /* Write the bits */
+   png_write_image(png_ptr, info_ptr->row_pointers);
+
+   /* It is REQUIRED to call this to finish writing the rest of the file */
+   png_write_end(png_ptr, info_ptr);
+
+   PNG_UNUSED(params)
+}
+#endif
+
+
+#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+/* Initialize the write structure - general purpose utility. */
+static int
+png_image_write_init(png_imagep image)
+{
+   png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
+       png_safe_error, png_safe_warning);
+
+   if (png_ptr != NULL)
+   {
+      png_infop info_ptr = png_create_info_struct(png_ptr);
+
+      if (info_ptr != NULL)
+      {
+         png_controlp control = png_voidcast(png_controlp,
+             png_malloc_warn(png_ptr, (sizeof *control)));
+
+         if (control != NULL)
+         {
+            memset(control, 0, (sizeof *control));
+
+            control->png_ptr = png_ptr;
+            control->info_ptr = info_ptr;
+            control->for_write = 1;
+
+            image->opaque = control;
+            return 1;
+         }
+
+         /* Error clean up */
+         png_destroy_info_struct(png_ptr, &info_ptr);
+      }
+
+      png_destroy_write_struct(&png_ptr, NULL);
+   }
+
+   return png_image_error(image, "png_image_write_: out of memory");
+}
+
+/* Arguments to png_image_write_main: */
+typedef struct
+{
+   /* Arguments: */
+   png_imagep      image;
+   png_const_voidp buffer;
+   png_int_32      row_stride;
+   png_const_voidp colormap;
+   int             convert_to_8bit;
+   /* Local variables: */
+   png_const_voidp first_row;
+   ptrdiff_t       row_bytes;
+   png_voidp       local_row;
+   /* Byte count for memory writing */
+   png_bytep        memory;
+   png_alloc_size_t memory_bytes; /* not used for STDIO */
+   png_alloc_size_t output_bytes; /* running total */
+} png_image_write_control;
+
+/* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
+ * do any necessary byte swapping.  The component order is defined by the
+ * png_image format value.
+ */
+static int
+png_write_image_16bit(png_voidp argument)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+
+   png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
+       display->first_row);
+   png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
+   png_uint_16p row_end;
+   unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
+       3 : 1;
+   int aindex = 0;
+   png_uint_32 y = image->height;
+
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+   {
+#   ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+      if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+      {
+         aindex = -1;
+         ++input_row; /* To point to the first component */
+         ++output_row;
+      }
+         else
+            aindex = (int)channels;
+#     else
+         aindex = (int)channels;
+#     endif
+   }
+
+   else
+      png_error(png_ptr, "png_write_image: internal call error");
+
+   /* Work out the output row end and count over this, note that the increment
+    * above to 'row' means that row_end can actually be beyond the end of the
+    * row; this is correct.
+    */
+   row_end = output_row + image->width * (channels+1);
+
+   for (; y > 0; --y)
+   {
+      png_const_uint_16p in_ptr = input_row;
+      png_uint_16p out_ptr = output_row;
+
+      while (out_ptr < row_end)
+      {
+         png_uint_16 alpha = in_ptr[aindex];
+         png_uint_32 reciprocal = 0;
+         int c;
+
+         out_ptr[aindex] = alpha;
+
+         /* Calculate a reciprocal.  The correct calculation is simply
+          * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
+          * allows correct rounding by adding .5 before the shift.  'reciprocal'
+          * is only initialized when required.
+          */
+         if (alpha > 0 && alpha < 65535)
+            reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
+
+         c = (int)channels;
+         do /* always at least one channel */
+         {
+            png_uint_16 component = *in_ptr++;
+
+            /* The following gives 65535 for an alpha of 0, which is fine,
+             * otherwise if 0/0 is represented as some other value there is more
+             * likely to be a discontinuity which will probably damage
+             * compression when moving from a fully transparent area to a
+             * nearly transparent one.  (The assumption here is that opaque
+             * areas tend not to be 0 intensity.)
+             */
+            if (component >= alpha)
+               component = 65535;
+
+            /* component<alpha, so component/alpha is less than one and
+             * component*reciprocal is less than 2^31.
+             */
+            else if (component > 0 && alpha < 65535)
+            {
+               png_uint_32 calc = component * reciprocal;
+               calc += 16384; /* round to nearest */
+               component = (png_uint_16)(calc >> 15);
+            }
+
+            *out_ptr++ = component;
+         }
+         while (--c > 0);
+
+         /* Skip to next component (skip the intervening alpha channel) */
+         ++in_ptr;
+         ++out_ptr;
+      }
+
+      png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
+      input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
+   }
+
+   return 1;
+}
+
+/* Given 16-bit input (1 to 4 channels) write 8-bit output.  If an alpha channel
+ * is present it must be removed from the components, the components are then
+ * written in sRGB encoding.  No components are added or removed.
+ *
+ * Calculate an alpha reciprocal to reverse pre-multiplication.  As above the
+ * calculation can be done to 15 bits of accuracy; however, the output needs to
+ * be scaled in the range 0..255*65535, so include that scaling here.
+ */
+#   define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha))
+
+static png_byte
+png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
+    png_uint_32 reciprocal/*from the above macro*/)
+{
+   /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
+    * is represented as some other value there is more likely to be a
+    * discontinuity which will probably damage compression when moving from a
+    * fully transparent area to a nearly transparent one.  (The assumption here
+    * is that opaque areas tend not to be 0 intensity.)
+    *
+    * There is a rounding problem here; if alpha is less than 128 it will end up
+    * as 0 when scaled to 8 bits.  To avoid introducing spurious colors into the
+    * output change for this too.
+    */
+   if (component >= alpha || alpha < 128)
+      return 255;
+
+   /* component<alpha, so component/alpha is less than one and
+    * component*reciprocal is less than 2^31.
+    */
+   else if (component > 0)
+   {
+      /* The test is that alpha/257 (rounded) is less than 255, the first value
+       * that becomes 255 is 65407.
+       * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
+       * be exact!)  [Could also test reciprocal != 0]
+       */
+      if (alpha < 65407)
+      {
+         component *= reciprocal;
+         component += 64; /* round to nearest */
+         component >>= 7;
+      }
+
+      else
+         component *= 255;
+
+      /* Convert the component to sRGB. */
+      return (png_byte)PNG_sRGB_FROM_LINEAR(component);
+   }
+
+   else
+      return 0;
+}
+
+static int
+png_write_image_8bit(png_voidp argument)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+
+   png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
+       display->first_row);
+   png_bytep output_row = png_voidcast(png_bytep, display->local_row);
+   png_uint_32 y = image->height;
+   unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
+       3 : 1;
+
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+   {
+      png_bytep row_end;
+      int aindex;
+
+#   ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+      if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+      {
+         aindex = -1;
+         ++input_row; /* To point to the first component */
+         ++output_row;
+      }
+
+      else
+#   endif
+      aindex = (int)channels;
+
+      /* Use row_end in place of a loop counter: */
+      row_end = output_row + image->width * (channels+1);
+
+      for (; y > 0; --y)
+      {
+         png_const_uint_16p in_ptr = input_row;
+         png_bytep out_ptr = output_row;
+
+         while (out_ptr < row_end)
+         {
+            png_uint_16 alpha = in_ptr[aindex];
+            png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
+            png_uint_32 reciprocal = 0;
+            int c;
+
+            /* Scale and write the alpha channel. */
+            out_ptr[aindex] = alphabyte;
+
+            if (alphabyte > 0 && alphabyte < 255)
+               reciprocal = UNP_RECIPROCAL(alpha);
+
+            c = (int)channels;
+            do /* always at least one channel */
+               *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
+            while (--c > 0);
+
+            /* Skip to next component (skip the intervening alpha channel) */
+            ++in_ptr;
+            ++out_ptr;
+         } /* while out_ptr < row_end */
+
+         png_write_row(png_ptr, png_voidcast(png_const_bytep,
+             display->local_row));
+         input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
+      } /* while y */
+   }
+
+   else
+   {
+      /* No alpha channel, so the row_end really is the end of the row and it
+       * is sufficient to loop over the components one by one.
+       */
+      png_bytep row_end = output_row + image->width * channels;
+
+      for (; y > 0; --y)
+      {
+         png_const_uint_16p in_ptr = input_row;
+         png_bytep out_ptr = output_row;
+
+         while (out_ptr < row_end)
+         {
+            png_uint_32 component = *in_ptr++;
+
+            component *= 255;
+            *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
+         }
+
+         png_write_row(png_ptr, output_row);
+         input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
+      }
+   }
+
+   return 1;
+}
+
+static void
+png_image_set_PLTE(png_image_write_control *display)
+{
+   png_imagep image = display->image;
+   const void *cmap = display->colormap;
+   int entries = image->colormap_entries > 256 ? 256 :
+       (int)image->colormap_entries;
+
+   /* NOTE: the caller must check for cmap != NULL and entries != 0 */
+   png_uint_32 format = image->format;
+   unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
+
+#   if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
+      defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
+      int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
+          (format & PNG_FORMAT_FLAG_ALPHA) != 0;
+#   else
+#     define afirst 0
+#   endif
+
+#   ifdef PNG_FORMAT_BGR_SUPPORTED
+      int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
+#   else
+#     define bgr 0
+#   endif
+
+   int i, num_trans;
+   png_color palette[256];
+   png_byte tRNS[256];
+
+   memset(tRNS, 255, (sizeof tRNS));
+   memset(palette, 0, (sizeof palette));
+
+   for (i=num_trans=0; i<entries; ++i)
+   {
+      /* This gets automatically converted to sRGB with reversal of the
+       * pre-multiplication if the color-map has an alpha channel.
+       */
+      if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
+      {
+         png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
+
+         entry += (unsigned int)i * channels;
+
+         if ((channels & 1) != 0) /* no alpha */
+         {
+            if (channels >= 3) /* RGB */
+            {
+               palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
+                   entry[(2 ^ bgr)]);
+               palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
+                   entry[1]);
+               palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
+                   entry[bgr]);
+            }
+
+            else /* Gray */
+               palette[i].blue = palette[i].red = palette[i].green =
+                  (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
+         }
+
+         else /* alpha */
+         {
+            png_uint_16 alpha = entry[afirst ? 0 : channels-1];
+            png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
+            png_uint_32 reciprocal = 0;
+
+            /* Calculate a reciprocal, as in the png_write_image_8bit code above
+             * this is designed to produce a value scaled to 255*65535 when
+             * divided by 128 (i.e. asr 7).
+             */
+            if (alphabyte > 0 && alphabyte < 255)
+               reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
+
+            tRNS[i] = alphabyte;
+            if (alphabyte < 255)
+               num_trans = i+1;
+
+            if (channels >= 3) /* RGB */
+            {
+               palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
+                   alpha, reciprocal);
+               palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
+                   reciprocal);
+               palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
+                   reciprocal);
+            }
+
+            else /* gray */
+               palette[i].blue = palette[i].red = palette[i].green =
+                   png_unpremultiply(entry[afirst], alpha, reciprocal);
+         }
+      }
+
+      else /* Color-map has sRGB values */
+      {
+         png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
+
+         entry += (unsigned int)i * channels;
+
+         switch (channels)
+         {
+            case 4:
+               tRNS[i] = entry[afirst ? 0 : 3];
+               if (tRNS[i] < 255)
+                  num_trans = i+1;
+               /* FALLTHROUGH */
+            case 3:
+               palette[i].blue = entry[afirst + (2 ^ bgr)];
+               palette[i].green = entry[afirst + 1];
+               palette[i].red = entry[afirst + bgr];
+               break;
+
+            case 2:
+               tRNS[i] = entry[1 ^ afirst];
+               if (tRNS[i] < 255)
+                  num_trans = i+1;
+               /* FALLTHROUGH */
+            case 1:
+               palette[i].blue = palette[i].red = palette[i].green =
+                  entry[afirst];
+               break;
+
+            default:
+               break;
+         }
+      }
+   }
+
+#   ifdef afirst
+#     undef afirst
+#   endif
+#   ifdef bgr
+#     undef bgr
+#   endif
+
+   png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
+       entries);
+
+   if (num_trans > 0)
+      png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
+          num_trans, NULL);
+
+   image->colormap_entries = (png_uint_32)entries;
+}
+
+static int
+png_image_write_main(png_voidp argument)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_inforp info_ptr = image->opaque->info_ptr;
+   png_uint_32 format = image->format;
+
+   /* The following four ints are actually booleans */
+   int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
+   int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
+   int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
+   int write_16bit = linear && (display->convert_to_8bit == 0);
+
+#   ifdef PNG_BENIGN_ERRORS_SUPPORTED
+      /* Make sure we error out on any bad situation */
+      png_set_benign_errors(png_ptr, 0/*error*/);
+#   endif
+
+   /* Default the 'row_stride' parameter if required, also check the row stride
+    * and total image size to ensure that they are within the system limits.
+    */
+   {
+      unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
+
+      if (image->width <= 0x7fffffffU/channels) /* no overflow */
+      {
+         png_uint_32 check;
+         png_uint_32 png_row_stride = image->width * channels;
+
+         if (display->row_stride == 0)
+            display->row_stride = (png_int_32)/*SAFE*/png_row_stride;
+
+         if (display->row_stride < 0)
+            check = (png_uint_32)(-display->row_stride);
+
+         else
+            check = (png_uint_32)display->row_stride;
+
+         if (check >= png_row_stride)
+         {
+            /* Now check for overflow of the image buffer calculation; this
+             * limits the whole image size to 32 bits for API compatibility with
+             * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
+             */
+            if (image->height > 0xffffffffU/png_row_stride)
+               png_error(image->opaque->png_ptr, "memory image too large");
+         }
+
+         else
+            png_error(image->opaque->png_ptr, "supplied row stride too small");
+      }
+
+      else
+         png_error(image->opaque->png_ptr, "image row stride too large");
+   }
+
+   /* Set the required transforms then write the rows in the correct order. */
+   if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+   {
+      if (display->colormap != NULL && image->colormap_entries > 0)
+      {
+         png_uint_32 entries = image->colormap_entries;
+
+         png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
+             entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
+             PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
+             PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+         png_image_set_PLTE(display);
+      }
+
+      else
+         png_error(image->opaque->png_ptr,
+             "no color-map for color-mapped image");
+   }
+
+   else
+      png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
+          write_16bit ? 16 : 8,
+          ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
+          ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
+          PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+   /* Counter-intuitively the data transformations must be called *after*
+    * png_write_info, not before as in the read code, but the 'set' functions
+    * must still be called before.  Just set the color space information, never
+    * write an interlaced image.
+    */
+
+   if (write_16bit != 0)
+   {
+      /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
+      png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
+
+      if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
+         png_set_cHRM_fixed(png_ptr, info_ptr,
+             /* color      x       y */
+             /* white */ 31270, 32900,
+             /* red   */ 64000, 33000,
+             /* green */ 30000, 60000,
+             /* blue  */ 15000,  6000
+         );
+   }
+
+   else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
+      png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
+
+   /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
+    * space must still be gamma encoded.
+    */
+   else
+      png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
+
+   /* Write the file header. */
+   png_write_info(png_ptr, info_ptr);
+
+   /* Now set up the data transformations (*after* the header is written),
+    * remove the handled transformations from the 'format' flags for checking.
+    *
+    * First check for a little endian system if writing 16-bit files.
+    */
+   if (write_16bit != 0)
+   {
+      png_uint_16 le = 0x0001;
+
+      if ((*(png_const_bytep) & le) != 0)
+         png_set_swap(png_ptr);
+   }
+
+#   ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
+      if ((format & PNG_FORMAT_FLAG_BGR) != 0)
+      {
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
+            png_set_bgr(png_ptr);
+         format &= ~PNG_FORMAT_FLAG_BGR;
+      }
+#   endif
+
+#   ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+      if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+      {
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            png_set_swap_alpha(png_ptr);
+         format &= ~PNG_FORMAT_FLAG_AFIRST;
+      }
+#   endif
+
+   /* If there are 16 or fewer color-map entries we wrote a lower bit depth
+    * above, but the application data is still byte packed.
+    */
+   if (colormap != 0 && image->colormap_entries <= 16)
+      png_set_packing(png_ptr);
+
+   /* That should have handled all (both) the transforms. */
+   if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
+         PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
+      png_error(png_ptr, "png_write_image: unsupported transformation");
+
+   {
+      png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
+      ptrdiff_t row_bytes = display->row_stride;
+
+      if (linear != 0)
+         row_bytes *= (sizeof (png_uint_16));
+
+      if (row_bytes < 0)
+         row += (image->height-1) * (-row_bytes);
+
+      display->first_row = row;
+      display->row_bytes = row_bytes;
+   }
+
+   /* Apply 'fast' options if the flag is set. */
+   if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
+   {
+      png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
+      /* NOTE: determined by experiment using pngstest, this reflects some
+       * balance between the time to write the image once and the time to read
+       * it about 50 times.  The speed-up in pngstest was about 10-20% of the
+       * total (user) time on a heavily loaded system.
+       */
+#   ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+      png_set_compression_level(png_ptr, 3);
+#   endif
+   }
+
+   /* Check for the cases that currently require a pre-transform on the row
+    * before it is written.  This only applies when the input is 16-bit and
+    * either there is an alpha channel or it is converted to 8-bit.
+    */
+   if ((linear != 0 && alpha != 0 ) ||
+       (colormap == 0 && display->convert_to_8bit != 0))
+   {
+      png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
+          png_get_rowbytes(png_ptr, info_ptr)));
+      int result;
+
+      display->local_row = row;
+      if (write_16bit != 0)
+         result = png_safe_execute(image, png_write_image_16bit, display);
+      else
+         result = png_safe_execute(image, png_write_image_8bit, display);
+      display->local_row = NULL;
+
+      png_free(png_ptr, row);
+
+      /* Skip the 'write_end' on error: */
+      if (result == 0)
+         return 0;
+   }
+
+   /* Otherwise this is the case where the input is in a format currently
+    * supported by the rest of the libpng write code; call it directly.
+    */
+   else
+   {
+      png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
+      ptrdiff_t row_bytes = display->row_bytes;
+      png_uint_32 y = image->height;
+
+      for (; y > 0; --y)
+      {
+         png_write_row(png_ptr, row);
+         row += row_bytes;
+      }
+   }
+
+   png_write_end(png_ptr, info_ptr);
+   return 1;
+}
+
+
+static void (PNGCBAPI
+image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data, size_t size)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       png_ptr->io_ptr/*backdoor: png_get_io_ptr(png_ptr)*/);
+   png_alloc_size_t ob = display->output_bytes;
+
+   /* Check for overflow; this should never happen: */
+   if (size <= ((png_alloc_size_t)-1) - ob)
+   {
+      /* I don't think libpng ever does this, but just in case: */
+      if (size > 0)
+      {
+         if (display->memory_bytes >= ob+size) /* writing */
+            memcpy(display->memory+ob, data, size);
+
+         /* Always update the size: */
+         display->output_bytes = ob+size;
+      }
+   }
+
+   else
+      png_error(png_ptr, "png_image_write_to_memory: PNG too big");
+}
+
+static void (PNGCBAPI
+image_memory_flush)(png_structp png_ptr)
+{
+   PNG_UNUSED(png_ptr)
+}
+
+static int
+png_image_write_memory(png_voidp argument)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       argument);
+
+   /* The rest of the memory-specific init and write_main in an error protected
+    * environment.  This case needs to use callbacks for the write operations
+    * since libpng has no built in support for writing to memory.
+    */
+   png_set_write_fn(display->image->opaque->png_ptr, display/*io_ptr*/,
+       image_memory_write, image_memory_flush);
+
+   return png_image_write_main(display);
+}
+
+int PNGAPI
+png_image_write_to_memory(png_imagep image, void *memory,
+    png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8bit,
+    const void *buffer, png_int_32 row_stride, const void *colormap)
+{
+   /* Write the image to the given buffer, or count the bytes if it is NULL */
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (memory_bytes != NULL && buffer != NULL)
+      {
+         /* This is to give the caller an easier error detection in the NULL
+          * case and guard against uninitialized variable problems:
+          */
+         if (memory == NULL)
+            *memory_bytes = 0;
+
+         if (png_image_write_init(image) != 0)
+         {
+            png_image_write_control display;
+            int result;
+
+            memset(&display, 0, (sizeof display));
+            display.image = image;
+            display.buffer = buffer;
+            display.row_stride = row_stride;
+            display.colormap = colormap;
+            display.convert_to_8bit = convert_to_8bit;
+            display.memory = png_voidcast(png_bytep, memory);
+            display.memory_bytes = *memory_bytes;
+            display.output_bytes = 0;
+
+            result = png_safe_execute(image, png_image_write_memory, &display);
+            png_image_free(image);
+
+            /* write_memory returns true even if we ran out of buffer. */
+            if (result)
+            {
+               /* On out-of-buffer this function returns '0' but still updates
+                * memory_bytes:
+                */
+               if (memory != NULL && display.output_bytes > *memory_bytes)
+                  result = 0;
+
+               *memory_bytes = display.output_bytes;
+            }
+
+            return result;
+         }
+
+         else
+            return 0;
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_write_to_memory: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
+
+   else
+      return 0;
+}
+
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+int PNGAPI
+png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
+    const void *buffer, png_int_32 row_stride, const void *colormap)
+{
+   /* Write the image to the given (FILE*). */
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (file != NULL && buffer != NULL)
+      {
+         if (png_image_write_init(image) != 0)
+         {
+            png_image_write_control display;
+            int result;
+
+            /* This is slightly evil, but png_init_io doesn't do anything other
+             * than this and we haven't changed the standard IO functions so
+             * this saves a 'safe' function.
+             */
+            image->opaque->png_ptr->io_ptr = file;
+
+            memset(&display, 0, (sizeof display));
+            display.image = image;
+            display.buffer = buffer;
+            display.row_stride = row_stride;
+            display.colormap = colormap;
+            display.convert_to_8bit = convert_to_8bit;
+
+            result = png_safe_execute(image, png_image_write_main, &display);
+            png_image_free(image);
+            return result;
+         }
+
+         else
+            return 0;
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_write_to_stdio: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
+
+   else
+      return 0;
+}
+
+int PNGAPI
+png_image_write_to_file(png_imagep image, const char *file_name,
+    int convert_to_8bit, const void *buffer, png_int_32 row_stride,
+    const void *colormap)
+{
+   /* Write the image to the named file. */
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (file_name != NULL && buffer != NULL)
+      {
+         FILE *fp = fopen(file_name, "wb");
+
+         if (fp != NULL)
+         {
+            if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
+                row_stride, colormap) != 0)
+            {
+               int error; /* from fflush/fclose */
+
+               /* Make sure the file is flushed correctly. */
+               if (fflush(fp) == 0 && ferror(fp) == 0)
+               {
+                  if (fclose(fp) == 0)
+                     return 1;
+
+                  error = errno; /* from fclose */
+               }
+
+               else
+               {
+                  error = errno; /* from fflush or ferror */
+                  (void)fclose(fp);
+               }
+
+               (void)remove(file_name);
+               /* The image has already been cleaned up; this is just used to
+                * set the error (because the original write succeeded).
+                */
+               return png_image_error(image, strerror(error));
+            }
+
+            else
+            {
+               /* Clean up: just the opened file. */
+               (void)fclose(fp);
+               (void)remove(file_name);
+               return 0;
+            }
+         }
+
+         else
+            return png_image_error(image, strerror(errno));
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_write_to_file: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
+
+   else
+      return 0;
+}
+#endif /* SIMPLIFIED_WRITE_STDIO */
+#endif /* SIMPLIFIED_WRITE */
+#endif /* WRITE */
diff --git a/extern/libpng/pngwtran.c b/extern/libpng/pngwtran.c
new file mode 100644
index 0000000000..49a13c1e98
--- /dev/null
+++ b/extern/libpng/pngwtran.c
@@ -0,0 +1,575 @@
+
+/* pngwtran.c - transforms the data in a row for PNG writers
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+
+#ifdef PNG_WRITE_PACK_SUPPORTED
+/* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
+ * row_info bit depth should be 8 (one pixel per byte).  The channels
+ * should be 1 (this only happens on grayscale and paletted images).
+ */
+static void
+png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
+{
+   png_debug(1, "in png_do_pack");
+
+   if (row_info->bit_depth == 8 &&
+      row_info->channels == 1)
+   {
+      switch ((int)bit_depth)
+      {
+         case 1:
+         {
+            png_bytep sp, dp;
+            int mask, v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            mask = 0x80;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               if (*sp != 0)
+                  v |= mask;
+
+               sp++;
+
+               if (mask > 1)
+                  mask >>= 1;
+
+               else
+               {
+                  mask = 0x80;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+            }
+
+            if (mask != 0x80)
+               *dp = (png_byte)v;
+
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp, dp;
+            unsigned int shift;
+            int v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            shift = 6;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte value;
+
+               value = (png_byte)(*sp & 0x03);
+               v |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 6;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+
+               else
+                  shift -= 2;
+
+               sp++;
+            }
+
+            if (shift != 6)
+               *dp = (png_byte)v;
+
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp, dp;
+            unsigned int shift;
+            int v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            shift = 4;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte value;
+
+               value = (png_byte)(*sp & 0x0f);
+               v |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 4;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+
+               else
+                  shift -= 4;
+
+               sp++;
+            }
+
+            if (shift != 4)
+               *dp = (png_byte)v;
+
+            break;
+         }
+
+         default:
+            break;
+      }
+
+      row_info->bit_depth = (png_byte)bit_depth;
+      row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+          row_info->width);
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+/* Shift pixel values to take advantage of whole range.  Pass the
+ * true number of bits in bit_depth.  The row should be packed
+ * according to row_info->bit_depth.  Thus, if you had a row of
+ * bit depth 4, but the pixels only had values from 0 to 7, you
+ * would pass 3 as bit_depth, and this routine would translate the
+ * data to 0 to 15.
+ */
+static void
+png_do_shift(png_row_infop row_info, png_bytep row,
+    png_const_color_8p bit_depth)
+{
+   png_debug(1, "in png_do_shift");
+
+   if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      int shift_start[4], shift_dec[4];
+      unsigned int channels = 0;
+
+      if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->red;
+         shift_dec[channels] = bit_depth->red;
+         channels++;
+
+         shift_start[channels] = row_info->bit_depth - bit_depth->green;
+         shift_dec[channels] = bit_depth->green;
+         channels++;
+
+         shift_start[channels] = row_info->bit_depth - bit_depth->blue;
+         shift_dec[channels] = bit_depth->blue;
+         channels++;
+      }
+
+      else
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->gray;
+         shift_dec[channels] = bit_depth->gray;
+         channels++;
+      }
+
+      if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
+         shift_dec[channels] = bit_depth->alpha;
+         channels++;
+      }
+
+      /* With low row depths, could only be grayscale, so one channel */
+      if (row_info->bit_depth < 8)
+      {
+         png_bytep bp = row;
+         size_t i;
+         unsigned int mask;
+         size_t row_bytes = row_info->rowbytes;
+
+         if (bit_depth->gray == 1 && row_info->bit_depth == 2)
+            mask = 0x55;
+
+         else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
+            mask = 0x11;
+
+         else
+            mask = 0xff;
+
+         for (i = 0; i < row_bytes; i++, bp++)
+         {
+            int j;
+            unsigned int v, out;
+
+            v = *bp;
+            out = 0;
+
+            for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
+            {
+               if (j > 0)
+                  out |= v << j;
+
+               else
+                  out |= (v >> (-j)) & mask;
+            }
+
+            *bp = (png_byte)(out & 0xff);
+         }
+      }
+
+      else if (row_info->bit_depth == 8)
+      {
+         png_bytep bp = row;
+         png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
+
+         for (i = 0; i < istop; i++, bp++)
+         {
+            unsigned int c = i%channels;
+            int j;
+            unsigned int v, out;
+
+            v = *bp;
+            out = 0;
+
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+            {
+               if (j > 0)
+                  out |= v << j;
+
+               else
+                  out |= v >> (-j);
+            }
+
+            *bp = (png_byte)(out & 0xff);
+         }
+      }
+
+      else
+      {
+         png_bytep bp;
+         png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
+
+         for (bp = row, i = 0; i < istop; i++)
+         {
+            unsigned int c = i%channels;
+            int j;
+            unsigned int value, v;
+
+            v = png_get_uint_16(bp);
+            value = 0;
+
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+            {
+               if (j > 0)
+                  value |= v << j;
+
+               else
+                  value |= v >> (-j);
+            }
+            *bp++ = (png_byte)((value >> 8) & 0xff);
+            *bp++ = (png_byte)(value & 0xff);
+         }
+      }
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+static void
+png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_swap_alpha");
+
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This converts from ARGB to RGBA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save;
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This converts from AARRGGBB to RRGGBBAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save[2];
+               save[0] = *(sp++);
+               save[1] = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save[0];
+               *(dp++) = save[1];
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This converts from AG to GA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save;
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This converts from AAGG to GGAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save[2];
+               save[0] = *(sp++);
+               save[1] = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save[0];
+               *(dp++) = save[1];
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+static void
+png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_invert_alpha");
+
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This inverts the alpha channel in RGBA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* Does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=3; dp = sp;
+               *dp = (png_byte)(255 - *(sp++));
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This inverts the alpha channel in RRGGBBAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* Does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=6; dp = sp;
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *dp     = (png_byte)(255 - *(sp++));
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This inverts the alpha channel in GA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               *(dp++) = *(sp++);
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This inverts the alpha channel in GGAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* Does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=2; dp = sp;
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *dp     = (png_byte)(255 - *(sp++));
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+   }
+}
+#endif
+
+/* Transform the data according to the user's wishes.  The order of
+ * transformations is significant.
+ */
+void /* PRIVATE */
+png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
+{
+   png_debug(1, "in png_do_write_transformations");
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+      if (png_ptr->write_user_transform_fn != NULL)
+         (*(png_ptr->write_user_transform_fn)) /* User write transform
+                                                 function */
+             (png_ptr,  /* png_ptr */
+             row_info,  /* row_info: */
+                /*  png_uint_32 width;       width of row */
+                /*  size_t rowbytes;         number of bytes in row */
+                /*  png_byte color_type;     color type of pixels */
+                /*  png_byte bit_depth;      bit depth of samples */
+                /*  png_byte channels;       number of channels (1-4) */
+                /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
+             png_ptr->row_buf + 1);      /* start of pixel data for row */
+#endif
+
+#ifdef PNG_WRITE_FILLER_SUPPORTED
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
+      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+          !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
+#endif
+
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+      png_do_packswap(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_PACK_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACK) != 0)
+      png_do_pack(row_info, png_ptr->row_buf + 1,
+          (png_uint_32)png_ptr->bit_depth);
+#endif
+
+#ifdef PNG_WRITE_SWAP_SUPPORTED
+#  ifdef PNG_16BIT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+      png_do_swap(row_info, png_ptr->row_buf + 1);
+#  endif
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
+      png_do_shift(row_info, png_ptr->row_buf + 1,
+           &(png_ptr->shift));
+#endif
+
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
+      png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_BGR_SUPPORTED
+   if ((png_ptr->transformations & PNG_BGR) != 0)
+      png_do_bgr(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+      png_do_invert(row_info, png_ptr->row_buf + 1);
+#endif
+}
+#endif /* WRITE_TRANSFORMS */
+#endif /* WRITE */
diff --git a/extern/libpng/pngwutil.c b/extern/libpng/pngwutil.c
new file mode 100644
index 0000000000..16345e4c0b
--- /dev/null
+++ b/extern/libpng/pngwutil.c
@@ -0,0 +1,2781 @@
+
+/* pngwutil.c - utilities to write a PNG file
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+/* Place a 32-bit number into a buffer in PNG byte order.  We work
+ * with unsigned numbers for convenience, although one supported
+ * ancillary chunk uses signed (two's complement) numbers.
+ */
+void PNGAPI
+png_save_uint_32(png_bytep buf, png_uint_32 i)
+{
+   buf[0] = (png_byte)((i >> 24) & 0xffU);
+   buf[1] = (png_byte)((i >> 16) & 0xffU);
+   buf[2] = (png_byte)((i >>  8) & 0xffU);
+   buf[3] = (png_byte)( i        & 0xffU);
+}
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+void PNGAPI
+png_save_uint_16(png_bytep buf, unsigned int i)
+{
+   buf[0] = (png_byte)((i >> 8) & 0xffU);
+   buf[1] = (png_byte)( i       & 0xffU);
+}
+#endif
+
+/* Simple function to write the signature.  If we have already written
+ * the magic bytes of the signature, or more likely, the PNG stream is
+ * being embedded into another stream and doesn't need its own signature,
+ * we should call png_set_sig_bytes() to tell libpng how many of the
+ * bytes have already been written.
+ */
+void PNGAPI
+png_write_sig(png_structrp png_ptr)
+{
+   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   /* Inform the I/O callback that the signature is being written */
+   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;
+#endif
+
+   /* Write the rest of the 8 byte signature */
+   png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
+       (size_t)(8 - png_ptr->sig_bytes));
+
+   if (png_ptr->sig_bytes < 3)
+      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
+/* Write the start of a PNG chunk.  The type is the chunk type.
+ * The total_length is the sum of the lengths of all the data you will be
+ * passing in png_write_chunk_data().
+ */
+static void
+png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name,
+    png_uint_32 length)
+{
+   png_byte buf[8];
+
+#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
+   PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
+   png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
+#endif
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   /* Inform the I/O callback that the chunk header is being written.
+    * PNG_IO_CHUNK_HDR requires a single I/O call.
+    */
+   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;
+#endif
+
+   /* Write the length and the chunk name */
+   png_save_uint_32(buf, length);
+   png_save_uint_32(buf + 4, chunk_name);
+   png_write_data(png_ptr, buf, 8);
+
+   /* Put the chunk name into png_ptr->chunk_name */
+   png_ptr->chunk_name = chunk_name;
+
+   /* Reset the crc and run it over the chunk name */
+   png_reset_crc(png_ptr);
+
+   png_calculate_crc(png_ptr, buf + 4, 4);
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   /* Inform the I/O callback that chunk data will (possibly) be written.
+    * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
+    */
+   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
+#endif
+}
+
+void PNGAPI
+png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string,
+    png_uint_32 length)
+{
+   png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
+}
+
+/* Write the data of a PNG chunk started with png_write_chunk_header().
+ * Note that multiple calls to this function are allowed, and that the
+ * sum of the lengths from these calls *must* add up to the total_length
+ * given to png_write_chunk_header().
+ */
+void PNGAPI
+png_write_chunk_data(png_structrp png_ptr, png_const_bytep data, size_t length)
+{
+   /* Write the data, and run the CRC over it */
+   if (png_ptr == NULL)
+      return;
+
+   if (data != NULL && length > 0)
+   {
+      png_write_data(png_ptr, data, length);
+
+      /* Update the CRC after writing the data,
+       * in case the user I/O routine alters it.
+       */
+      png_calculate_crc(png_ptr, data, length);
+   }
+}
+
+/* Finish a chunk started with png_write_chunk_header(). */
+void PNGAPI
+png_write_chunk_end(png_structrp png_ptr)
+{
+   png_byte buf[4];
+
+   if (png_ptr == NULL) return;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   /* Inform the I/O callback that the chunk CRC is being written.
+    * PNG_IO_CHUNK_CRC requires a single I/O function call.
+    */
+   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
+#endif
+
+   /* Write the crc in a single operation */
+   png_save_uint_32(buf, png_ptr->crc);
+
+   png_write_data(png_ptr, buf, 4);
+}
+
+/* Write a PNG chunk all at once.  The type is an array of ASCII characters
+ * representing the chunk name.  The array must be at least 4 bytes in
+ * length, and does not need to be null terminated.  To be safe, pass the
+ * pre-defined chunk names here, and if you need a new one, define it
+ * where the others are defined.  The length is the length of the data.
+ * All the data must be present.  If that is not possible, use the
+ * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
+ * functions instead.
+ */
+static void
+png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
+    png_const_bytep data, size_t length)
+{
+   if (png_ptr == NULL)
+      return;
+
+   /* On 64-bit architectures 'length' may not fit in a png_uint_32. */
+   if (length > PNG_UINT_31_MAX)
+      png_error(png_ptr, "length exceeds PNG maximum");
+
+   png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
+   png_write_chunk_data(png_ptr, data, length);
+   png_write_chunk_end(png_ptr);
+}
+
+/* This is the API that calls the internal function above. */
+void PNGAPI
+png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
+    png_const_bytep data, size_t length)
+{
+   png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
+       length);
+}
+
+/* This is used below to find the size of an image to pass to png_deflate_claim,
+ * so it only needs to be accurate if the size is less than 16384 bytes (the
+ * point at which a lower LZ window size can be used.)
+ */
+static png_alloc_size_t
+png_image_size(png_structrp png_ptr)
+{
+   /* Only return sizes up to the maximum of a png_uint_32; do this by limiting
+    * the width and height used to 15 bits.
+    */
+   png_uint_32 h = png_ptr->height;
+
+   if (png_ptr->rowbytes < 32768 && h < 32768)
+   {
+      if (png_ptr->interlaced != 0)
+      {
+         /* Interlacing makes the image larger because of the replication of
+          * both the filter byte and the padding to a byte boundary.
+          */
+         png_uint_32 w = png_ptr->width;
+         unsigned int pd = png_ptr->pixel_depth;
+         png_alloc_size_t cb_base;
+         int pass;
+
+         for (cb_base=0, pass=0; pass<=6; ++pass)
+         {
+            png_uint_32 pw = PNG_PASS_COLS(w, pass);
+
+            if (pw > 0)
+               cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass);
+         }
+
+         return cb_base;
+      }
+
+      else
+         return (png_ptr->rowbytes+1) * h;
+   }
+
+   else
+      return 0xffffffffU;
+}
+
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+   /* This is the code to hack the first two bytes of the deflate stream (the
+    * deflate header) to correct the windowBits value to match the actual data
+    * size.  Note that the second argument is the *uncompressed* size but the
+    * first argument is the *compressed* data (and it must be deflate
+    * compressed.)
+    */
+static void
+optimize_cmf(png_bytep data, png_alloc_size_t data_size)
+{
+   /* Optimize the CMF field in the zlib stream.  The resultant zlib stream is
+    * still compliant to the stream specification.
+    */
+   if (data_size <= 16384) /* else windowBits must be 15 */
+   {
+      unsigned int z_cmf = data[0];  /* zlib compression method and flags */
+
+      if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
+      {
+         unsigned int z_cinfo;
+         unsigned int half_z_window_size;
+
+         z_cinfo = z_cmf >> 4;
+         half_z_window_size = 1U << (z_cinfo + 7);
+
+         if (data_size <= half_z_window_size) /* else no change */
+         {
+            unsigned int tmp;
+
+            do
+            {
+               half_z_window_size >>= 1;
+               --z_cinfo;
+            }
+            while (z_cinfo > 0 && data_size <= half_z_window_size);
+
+            z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
+
+            data[0] = (png_byte)z_cmf;
+            tmp = data[1] & 0xe0;
+            tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
+            data[1] = (png_byte)tmp;
+         }
+      }
+   }
+}
+#endif /* WRITE_OPTIMIZE_CMF */
+
+/* Initialize the compressor for the appropriate type of compression. */
+static int
+png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
+    png_alloc_size_t data_size)
+{
+   if (png_ptr->zowner != 0)
+   {
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
+      char msg[64];
+
+      PNG_STRING_FROM_CHUNK(msg, owner);
+      msg[4] = ':';
+      msg[5] = ' ';
+      PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner);
+      /* So the message that results is "<chunk> using zstream"; this is an
+       * internal error, but is very useful for debugging.  i18n requirements
+       * are minimal.
+       */
+      (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
+#endif
+#if PNG_RELEASE_BUILD
+         png_warning(png_ptr, msg);
+
+         /* Attempt sane error recovery */
+         if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */
+         {
+            png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT");
+            return Z_STREAM_ERROR;
+         }
+
+         png_ptr->zowner = 0;
+#else
+         png_error(png_ptr, msg);
+#endif
+   }
+
+   {
+      int level = png_ptr->zlib_level;
+      int method = png_ptr->zlib_method;
+      int windowBits = png_ptr->zlib_window_bits;
+      int memLevel = png_ptr->zlib_mem_level;
+      int strategy; /* set below */
+      int ret; /* zlib return code */
+
+      if (owner == png_IDAT)
+      {
+         if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
+            strategy = png_ptr->zlib_strategy;
+
+         else if (png_ptr->do_filter != PNG_FILTER_NONE)
+            strategy = PNG_Z_DEFAULT_STRATEGY;
+
+         else
+            strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY;
+      }
+
+      else
+      {
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+            level = png_ptr->zlib_text_level;
+            method = png_ptr->zlib_text_method;
+            windowBits = png_ptr->zlib_text_window_bits;
+            memLevel = png_ptr->zlib_text_mem_level;
+            strategy = png_ptr->zlib_text_strategy;
+#else
+            /* If customization is not supported the values all come from the
+             * IDAT values except for the strategy, which is fixed to the
+             * default.  (This is the pre-1.6.0 behavior too, although it was
+             * implemented in a very different way.)
+             */
+            strategy = Z_DEFAULT_STRATEGY;
+#endif
+      }
+
+      /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
+       * happening just pass 32768 as the data_size parameter.  Notice that zlib
+       * requires an extra 262 bytes in the window in addition to the data to be
+       * able to see the whole of the data, so if data_size+262 takes us to the
+       * next windowBits size we need to fix up the value later.  (Because even
+       * though deflate needs the extra window, inflate does not!)
+       */
+      if (data_size <= 16384)
+      {
+         /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to
+          * work round a Microsoft Visual C misbehavior which, contrary to C-90,
+          * widens the result of the following shift to 64-bits if (and,
+          * apparently, only if) it is used in a test.
+          */
+         unsigned int half_window_size = 1U << (windowBits-1);
+
+         while (data_size + 262 <= half_window_size)
+         {
+            half_window_size >>= 1;
+            --windowBits;
+         }
+      }
+
+      /* Check against the previous initialized values, if any. */
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
+         (png_ptr->zlib_set_level != level ||
+         png_ptr->zlib_set_method != method ||
+         png_ptr->zlib_set_window_bits != windowBits ||
+         png_ptr->zlib_set_mem_level != memLevel ||
+         png_ptr->zlib_set_strategy != strategy))
+      {
+         if (deflateEnd(&png_ptr->zstream) != Z_OK)
+            png_warning(png_ptr, "deflateEnd failed (ignored)");
+
+         png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED;
+      }
+
+      /* For safety clear out the input and output pointers (currently zlib
+       * doesn't use them on Init, but it might in the future).
+       */
+      png_ptr->zstream.next_in = NULL;
+      png_ptr->zstream.avail_in = 0;
+      png_ptr->zstream.next_out = NULL;
+      png_ptr->zstream.avail_out = 0;
+
+      /* Now initialize if required, setting the new parameters, otherwise just
+       * do a simple reset to the previous parameters.
+       */
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+         ret = deflateReset(&png_ptr->zstream);
+
+      else
+      {
+         ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,
+             memLevel, strategy);
+
+         if (ret == Z_OK)
+            png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
+      }
+
+      /* The return code is from either deflateReset or deflateInit2; they have
+       * pretty much the same set of error codes.
+       */
+      if (ret == Z_OK)
+         png_ptr->zowner = owner;
+
+      else
+         png_zstream_error(png_ptr, ret);
+
+      return ret;
+   }
+}
+
+/* Clean up (or trim) a linked list of compression buffers. */
+void /* PRIVATE */
+png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp)
+{
+   png_compression_bufferp list = *listp;
+
+   if (list != NULL)
+   {
+      *listp = NULL;
+
+      do
+      {
+         png_compression_bufferp next = list->next;
+
+         png_free(png_ptr, list);
+         list = next;
+      }
+      while (list != NULL);
+   }
+}
+
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+/* This pair of functions encapsulates the operation of (a) compressing a
+ * text string, and (b) issuing it later as a series of chunk data writes.
+ * The compression_state structure is shared context for these functions
+ * set up by the caller to allow access to the relevant local variables.
+ *
+ * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size
+ * temporary buffers.  From 1.6.0 it is retained in png_struct so that it will
+ * be correctly freed in the event of a write error (previous implementations
+ * just leaked memory.)
+ */
+typedef struct
+{
+   png_const_bytep      input;        /* The uncompressed input data */
+   png_alloc_size_t     input_len;    /* Its length */
+   png_uint_32          output_len;   /* Final compressed length */
+   png_byte             output[1024]; /* First block of output */
+} compression_state;
+
+static void
+png_text_compress_init(compression_state *comp, png_const_bytep input,
+    png_alloc_size_t input_len)
+{
+   comp->input = input;
+   comp->input_len = input_len;
+   comp->output_len = 0;
+}
+
+/* Compress the data in the compression state input */
+static int
+png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
+    compression_state *comp, png_uint_32 prefix_len)
+{
+   int ret;
+
+   /* To find the length of the output it is necessary to first compress the
+    * input. The result is buffered rather than using the two-pass algorithm
+    * that is used on the inflate side; deflate is assumed to be slower and a
+    * PNG writer is assumed to have more memory available than a PNG reader.
+    *
+    * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an
+    * upper limit on the output size, but it is always bigger than the input
+    * size so it is likely to be more efficient to use this linked-list
+    * approach.
+    */
+   ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len);
+
+   if (ret != Z_OK)
+      return ret;
+
+   /* Set up the compression buffers, we need a loop here to avoid overflowing a
+    * uInt.  Use ZLIB_IO_MAX to limit the input.  The output is always limited
+    * by the output buffer size, so there is no need to check that.  Since this
+    * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits
+    * in size.
+    */
+   {
+      png_compression_bufferp *end = &png_ptr->zbuffer_list;
+      png_alloc_size_t input_len = comp->input_len; /* may be zero! */
+      png_uint_32 output_len;
+
+      /* zlib updates these for us: */
+      png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input);
+      png_ptr->zstream.avail_in = 0; /* Set below */
+      png_ptr->zstream.next_out = comp->output;
+      png_ptr->zstream.avail_out = (sizeof comp->output);
+
+      output_len = png_ptr->zstream.avail_out;
+
+      do
+      {
+         uInt avail_in = ZLIB_IO_MAX;
+
+         if (avail_in > input_len)
+            avail_in = (uInt)input_len;
+
+         input_len -= avail_in;
+
+         png_ptr->zstream.avail_in = avail_in;
+
+         if (png_ptr->zstream.avail_out == 0)
+         {
+            png_compression_buffer *next;
+
+            /* Chunk data is limited to 2^31 bytes in length, so the prefix
+             * length must be counted here.
+             */
+            if (output_len + prefix_len > PNG_UINT_31_MAX)
+            {
+               ret = Z_MEM_ERROR;
+               break;
+            }
+
+            /* Need a new (malloc'ed) buffer, but there may be one present
+             * already.
+             */
+            next = *end;
+            if (next == NULL)
+            {
+               next = png_voidcast(png_compression_bufferp, png_malloc_base
+                  (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
+
+               if (next == NULL)
+               {
+                  ret = Z_MEM_ERROR;
+                  break;
+               }
+
+               /* Link in this buffer (so that it will be freed later) */
+               next->next = NULL;
+               *end = next;
+            }
+
+            png_ptr->zstream.next_out = next->output;
+            png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
+            output_len += png_ptr->zstream.avail_out;
+
+            /* Move 'end' to the next buffer pointer. */
+            end = &next->next;
+         }
+
+         /* Compress the data */
+         ret = deflate(&png_ptr->zstream,
+             input_len > 0 ? Z_NO_FLUSH : Z_FINISH);
+
+         /* Claw back input data that was not consumed (because avail_in is
+          * reset above every time round the loop).
+          */
+         input_len += png_ptr->zstream.avail_in;
+         png_ptr->zstream.avail_in = 0; /* safety */
+      }
+      while (ret == Z_OK);
+
+      /* There may be some space left in the last output buffer. This needs to
+       * be subtracted from output_len.
+       */
+      output_len -= png_ptr->zstream.avail_out;
+      png_ptr->zstream.avail_out = 0; /* safety */
+      comp->output_len = output_len;
+
+      /* Now double check the output length, put in a custom message if it is
+       * too long.  Otherwise ensure the z_stream::msg pointer is set to
+       * something.
+       */
+      if (output_len + prefix_len >= PNG_UINT_31_MAX)
+      {
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long");
+         ret = Z_MEM_ERROR;
+      }
+
+      else
+         png_zstream_error(png_ptr, ret);
+
+      /* Reset zlib for another zTXt/iTXt or image data */
+      png_ptr->zowner = 0;
+
+      /* The only success case is Z_STREAM_END, input_len must be 0; if not this
+       * is an internal error.
+       */
+      if (ret == Z_STREAM_END && input_len == 0)
+      {
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+         /* Fix up the deflate header, if required */
+         optimize_cmf(comp->output, comp->input_len);
+#endif
+         /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
+          * function above to return Z_STREAM_END on an error (though it never
+          * does in the current versions of zlib.)
+          */
+         return Z_OK;
+      }
+
+      else
+         return ret;
+   }
+}
+
+/* Ship the compressed text out via chunk writes */
+static void
+png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
+{
+   png_uint_32 output_len = comp->output_len;
+   png_const_bytep output = comp->output;
+   png_uint_32 avail = (sizeof comp->output);
+   png_compression_buffer *next = png_ptr->zbuffer_list;
+
+   for (;;)
+   {
+      if (avail > output_len)
+         avail = output_len;
+
+      png_write_chunk_data(png_ptr, output, avail);
+
+      output_len -= avail;
+
+      if (output_len == 0 || next == NULL)
+         break;
+
+      avail = png_ptr->zbuffer_size;
+      output = next->output;
+      next = next->next;
+   }
+
+   /* This is an internal error; 'next' must have been NULL! */
+   if (output_len > 0)
+      png_error(png_ptr, "error writing ancillary chunked compressed data");
+}
+#endif /* WRITE_COMPRESSED_TEXT */
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information.  Note that the rest of this code depends upon this
+ * information being correct.
+ */
+void /* PRIVATE */
+png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
+    int bit_depth, int color_type, int compression_type, int filter_type,
+    int interlace_type)
+{
+   png_byte buf[13]; /* Buffer to store the IHDR info */
+   int is_invalid_depth;
+
+   png_debug(1, "in png_write_IHDR");
+
+   /* Check that we have valid input data from the application info */
+   switch (color_type)
+   {
+      case PNG_COLOR_TYPE_GRAY:
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+            case 8:
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+            case 16:
+#endif
+               png_ptr->channels = 1; break;
+
+            default:
+               png_error(png_ptr,
+                   "Invalid bit depth for grayscale image");
+         }
+         break;
+
+      case PNG_COLOR_TYPE_RGB:
+         is_invalid_depth = (bit_depth != 8);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         is_invalid_depth = (is_invalid_depth && bit_depth != 16);
+#endif
+         if (is_invalid_depth)
+            png_error(png_ptr, "Invalid bit depth for RGB image");
+
+         png_ptr->channels = 3;
+         break;
+
+      case PNG_COLOR_TYPE_PALETTE:
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+            case 8:
+               png_ptr->channels = 1;
+               break;
+
+            default:
+               png_error(png_ptr, "Invalid bit depth for paletted image");
+         }
+         break;
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         is_invalid_depth = (bit_depth != 8);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         is_invalid_depth = (is_invalid_depth && bit_depth != 16);
+#endif
+         if (is_invalid_depth)
+            png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
+
+         png_ptr->channels = 2;
+         break;
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         is_invalid_depth = (bit_depth != 8);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         is_invalid_depth = (is_invalid_depth && bit_depth != 16);
+#endif
+         if (is_invalid_depth)
+            png_error(png_ptr, "Invalid bit depth for RGBA image");
+
+         png_ptr->channels = 4;
+         break;
+
+      default:
+         png_error(png_ptr, "Invalid image color type specified");
+   }
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Invalid compression type specified");
+      compression_type = PNG_COMPRESSION_TYPE_BASE;
+   }
+
+   /* Write filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not write a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if (
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
+       (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
+       (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
+#endif
+       filter_type != PNG_FILTER_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Invalid filter type specified");
+      filter_type = PNG_FILTER_TYPE_BASE;
+   }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   if (interlace_type != PNG_INTERLACE_NONE &&
+       interlace_type != PNG_INTERLACE_ADAM7)
+   {
+      png_warning(png_ptr, "Invalid interlace type specified");
+      interlace_type = PNG_INTERLACE_ADAM7;
+   }
+#else
+   interlace_type=PNG_INTERLACE_NONE;
+#endif
+
+   /* Save the relevant information */
+   png_ptr->bit_depth = (png_byte)bit_depth;
+   png_ptr->color_type = (png_byte)color_type;
+   png_ptr->interlaced = (png_byte)interlace_type;
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   png_ptr->filter_type = (png_byte)filter_type;
+#endif
+   png_ptr->compression_type = (png_byte)compression_type;
+   png_ptr->width = width;
+   png_ptr->height = height;
+
+   png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
+   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
+   /* Set the usr info, so any transformations can modify it */
+   png_ptr->usr_width = png_ptr->width;
+   png_ptr->usr_bit_depth = png_ptr->bit_depth;
+   png_ptr->usr_channels = png_ptr->channels;
+
+   /* Pack the header information into the buffer */
+   png_save_uint_32(buf, width);
+   png_save_uint_32(buf + 4, height);
+   buf[8] = (png_byte)bit_depth;
+   buf[9] = (png_byte)color_type;
+   buf[10] = (png_byte)compression_type;
+   buf[11] = (png_byte)filter_type;
+   buf[12] = (png_byte)interlace_type;
+
+   /* Write the chunk */
+   png_write_complete_chunk(png_ptr, png_IHDR, buf, 13);
+
+   if ((png_ptr->do_filter) == PNG_NO_FILTERS)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
+          png_ptr->bit_depth < 8)
+         png_ptr->do_filter = PNG_FILTER_NONE;
+
+      else
+         png_ptr->do_filter = PNG_ALL_FILTERS;
+   }
+
+   png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
+}
+
+/* Write the palette.  We are careful not to trust png_color to be in the
+ * correct order for PNG, so people can redefine it to any convenient
+ * structure.
+ */
+void /* PRIVATE */
+png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
+    png_uint_32 num_pal)
+{
+   png_uint_32 max_palette_length, i;
+   png_const_colorp pal_ptr;
+   png_byte buf[3];
+
+   png_debug(1, "in png_write_PLTE");
+
+   max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
+      (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
+
+   if ((
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+       (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
+#endif
+       num_pal == 0) || num_pal > max_palette_length)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         png_error(png_ptr, "Invalid number of colors in palette");
+      }
+
+      else
+      {
+         png_warning(png_ptr, "Invalid number of colors in palette");
+         return;
+      }
+   }
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+   {
+      png_warning(png_ptr,
+          "Ignoring request to write a PLTE chunk in grayscale PNG");
+
+      return;
+   }
+
+   png_ptr->num_palette = (png_uint_16)num_pal;
+   png_debug1(3, "num_palette = %d", png_ptr->num_palette);
+
+   png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+
+   for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
+   {
+      buf[0] = pal_ptr->red;
+      buf[1] = pal_ptr->green;
+      buf[2] = pal_ptr->blue;
+      png_write_chunk_data(png_ptr, buf, 3);
+   }
+
+#else
+   /* This is a little slower but some buggy compilers need to do this
+    * instead
+    */
+   pal_ptr=palette;
+
+   for (i = 0; i < num_pal; i++)
+   {
+      buf[0] = pal_ptr[i].red;
+      buf[1] = pal_ptr[i].green;
+      buf[2] = pal_ptr[i].blue;
+      png_write_chunk_data(png_ptr, buf, 3);
+   }
+
+#endif
+   png_write_chunk_end(png_ptr);
+   png_ptr->mode |= PNG_HAVE_PLTE;
+}
+
+/* This is similar to png_text_compress, above, except that it does not require
+ * all of the data at once and, instead of buffering the compressed result,
+ * writes it as IDAT chunks.  Unlike png_text_compress it *can* png_error out
+ * because it calls the write interface.  As a result it does its own error
+ * reporting and does not return an error code.  In the event of error it will
+ * just call png_error.  The input data length may exceed 32-bits.  The 'flush'
+ * parameter is exactly the same as that to deflate, with the following
+ * meanings:
+ *
+ * Z_NO_FLUSH: normal incremental output of compressed data
+ * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush
+ * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
+ *
+ * The routine manages the acquire and release of the png_ptr->zstream by
+ * checking and (at the end) clearing png_ptr->zowner; it does some sanity
+ * checks on the 'mode' flags while doing this.
+ */
+void /* PRIVATE */
+png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
+    png_alloc_size_t input_len, int flush)
+{
+   if (png_ptr->zowner != png_IDAT)
+   {
+      /* First time.   Ensure we have a temporary buffer for compression and
+       * trim the buffer list if it has more than one entry to free memory.
+       * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been
+       * created at this point, but the check here is quick and safe.
+       */
+      if (png_ptr->zbuffer_list == NULL)
+      {
+         png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp,
+             png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
+         png_ptr->zbuffer_list->next = NULL;
+      }
+
+      else
+         png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next);
+
+      /* It is a terminal error if we can't claim the zstream. */
+      if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK)
+         png_error(png_ptr, png_ptr->zstream.msg);
+
+      /* The output state is maintained in png_ptr->zstream, so it must be
+       * initialized here after the claim.
+       */
+      png_ptr->zstream.next_out = png_ptr->zbuffer_list->output;
+      png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
+   }
+
+   /* Now loop reading and writing until all the input is consumed or an error
+    * terminates the operation.  The _out values are maintained across calls to
+    * this function, but the input must be reset each time.
+    */
+   png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
+   png_ptr->zstream.avail_in = 0; /* set below */
+   for (;;)
+   {
+      int ret;
+
+      /* INPUT: from the row data */
+      uInt avail = ZLIB_IO_MAX;
+
+      if (avail > input_len)
+         avail = (uInt)input_len; /* safe because of the check */
+
+      png_ptr->zstream.avail_in = avail;
+      input_len -= avail;
+
+      ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush);
+
+      /* Include as-yet unconsumed input */
+      input_len += png_ptr->zstream.avail_in;
+      png_ptr->zstream.avail_in = 0;
+
+      /* OUTPUT: write complete IDAT chunks when avail_out drops to zero. Note
+       * that these two zstream fields are preserved across the calls, therefore
+       * there is no need to set these up on entry to the loop.
+       */
+      if (png_ptr->zstream.avail_out == 0)
+      {
+         png_bytep data = png_ptr->zbuffer_list->output;
+         uInt size = png_ptr->zbuffer_size;
+
+         /* Write an IDAT containing the data then reset the buffer.  The
+          * first IDAT may need deflate header optimization.
+          */
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+            if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+                png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+               optimize_cmf(data, png_image_size(png_ptr));
+#endif
+
+         if (size > 0)
+            png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+         png_ptr->mode |= PNG_HAVE_IDAT;
+
+         png_ptr->zstream.next_out = data;
+         png_ptr->zstream.avail_out = size;
+
+         /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with
+          * the same flush parameter until it has finished output, for NO_FLUSH
+          * it doesn't matter.
+          */
+         if (ret == Z_OK && flush != Z_NO_FLUSH)
+            continue;
+      }
+
+      /* The order of these checks doesn't matter much; it just affects which
+       * possible error might be detected if multiple things go wrong at once.
+       */
+      if (ret == Z_OK) /* most likely return code! */
+      {
+         /* If all the input has been consumed then just return.  If Z_FINISH
+          * was used as the flush parameter something has gone wrong if we get
+          * here.
+          */
+         if (input_len == 0)
+         {
+            if (flush == Z_FINISH)
+               png_error(png_ptr, "Z_OK on Z_FINISH with output space");
+
+            return;
+         }
+      }
+
+      else if (ret == Z_STREAM_END && flush == Z_FINISH)
+      {
+         /* This is the end of the IDAT data; any pending output must be
+          * flushed.  For small PNG files we may still be at the beginning.
+          */
+         png_bytep data = png_ptr->zbuffer_list->output;
+         uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;
+
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+         if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+             png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+            optimize_cmf(data, png_image_size(png_ptr));
+#endif
+
+         if (size > 0)
+            png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+         png_ptr->zstream.avail_out = 0;
+         png_ptr->zstream.next_out = NULL;
+         png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;
+
+         png_ptr->zowner = 0; /* Release the stream */
+         return;
+      }
+
+      else
+      {
+         /* This is an error condition. */
+         png_zstream_error(png_ptr, ret);
+         png_error(png_ptr, png_ptr->zstream.msg);
+      }
+   }
+}
+
+/* Write an IEND chunk */
+void /* PRIVATE */
+png_write_IEND(png_structrp png_ptr)
+{
+   png_debug(1, "in png_write_IEND");
+
+   png_write_complete_chunk(png_ptr, png_IEND, NULL, 0);
+   png_ptr->mode |= PNG_HAVE_IEND;
+}
+
+#ifdef PNG_WRITE_gAMA_SUPPORTED
+/* Write a gAMA chunk */
+void /* PRIVATE */
+png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma)
+{
+   png_byte buf[4];
+
+   png_debug(1, "in png_write_gAMA");
+
+   /* file_gamma is saved in 1/100,000ths */
+   png_save_uint_32(buf, (png_uint_32)file_gamma);
+   png_write_complete_chunk(png_ptr, png_gAMA, buf, 4);
+}
+#endif
+
+#ifdef PNG_WRITE_sRGB_SUPPORTED
+/* Write a sRGB chunk */
+void /* PRIVATE */
+png_write_sRGB(png_structrp png_ptr, int srgb_intent)
+{
+   png_byte buf[1];
+
+   png_debug(1, "in png_write_sRGB");
+
+   if (srgb_intent >= PNG_sRGB_INTENT_LAST)
+      png_warning(png_ptr,
+          "Invalid sRGB rendering intent specified");
+
+   buf[0]=(png_byte)srgb_intent;
+   png_write_complete_chunk(png_ptr, png_sRGB, buf, 1);
+}
+#endif
+
+#ifdef PNG_WRITE_iCCP_SUPPORTED
+/* Write an iCCP chunk */
+void /* PRIVATE */
+png_write_iCCP(png_structrp png_ptr, png_const_charp name,
+    png_const_bytep profile)
+{
+   png_uint_32 name_len;
+   png_uint_32 profile_len;
+   png_byte new_name[81]; /* 1 byte for the compression byte */
+   compression_state comp;
+   png_uint_32 temp;
+
+   png_debug(1, "in png_write_iCCP");
+
+   /* These are all internal problems: the profile should have been checked
+    * before when it was stored.
+    */
+   if (profile == NULL)
+      png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */
+
+   profile_len = png_get_uint_32(profile);
+
+   if (profile_len < 132)
+      png_error(png_ptr, "ICC profile too short");
+
+   temp = (png_uint_32) (*(profile+8));
+   if (temp > 3 && (profile_len & 0x03))
+      png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");
+
+   {
+      png_uint_32 embedded_profile_len = png_get_uint_32(profile);
+
+      if (profile_len != embedded_profile_len)
+         png_error(png_ptr, "Profile length does not match profile");
+   }
+
+   name_len = png_check_keyword(png_ptr, name, new_name);
+
+   if (name_len == 0)
+      png_error(png_ptr, "iCCP: invalid keyword");
+
+   new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE;
+
+   /* Make sure we include the NULL after the name and the compression type */
+   ++name_len;
+
+   png_text_compress_init(&comp, profile, profile_len);
+
+   /* Allow for keyword terminator and compression byte */
+   if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK)
+      png_error(png_ptr, png_ptr->zstream.msg);
+
+   png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len);
+
+   png_write_chunk_data(png_ptr, new_name, name_len);
+
+   png_write_compressed_data_out(png_ptr, &comp);
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+/* Write a sPLT chunk */
+void /* PRIVATE */
+png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
+{
+   png_uint_32 name_len;
+   png_byte new_name[80];
+   png_byte entrybuf[10];
+   size_t entry_size = (spalette->depth == 8 ? 6 : 10);
+   size_t palette_size = entry_size * (size_t)spalette->nentries;
+   png_sPLT_entryp ep;
+#ifndef PNG_POINTER_INDEXING_SUPPORTED
+   int i;
+#endif
+
+   png_debug(1, "in png_write_sPLT");
+
+   name_len = png_check_keyword(png_ptr, spalette->name, new_name);
+
+   if (name_len == 0)
+      png_error(png_ptr, "sPLT: invalid keyword");
+
+   /* Make sure we include the NULL after the name */
+   png_write_chunk_header(png_ptr, png_sPLT,
+       (png_uint_32)(name_len + 2 + palette_size));
+
+   png_write_chunk_data(png_ptr, (png_bytep)new_name, (size_t)(name_len + 1));
+
+   png_write_chunk_data(png_ptr, &spalette->depth, 1);
+
+   /* Loop through each palette entry, writing appropriately */
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+   for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
+   {
+      if (spalette->depth == 8)
+      {
+         entrybuf[0] = (png_byte)ep->red;
+         entrybuf[1] = (png_byte)ep->green;
+         entrybuf[2] = (png_byte)ep->blue;
+         entrybuf[3] = (png_byte)ep->alpha;
+         png_save_uint_16(entrybuf + 4, ep->frequency);
+      }
+
+      else
+      {
+         png_save_uint_16(entrybuf + 0, ep->red);
+         png_save_uint_16(entrybuf + 2, ep->green);
+         png_save_uint_16(entrybuf + 4, ep->blue);
+         png_save_uint_16(entrybuf + 6, ep->alpha);
+         png_save_uint_16(entrybuf + 8, ep->frequency);
+      }
+
+      png_write_chunk_data(png_ptr, entrybuf, entry_size);
+   }
+#else
+   ep=spalette->entries;
+   for (i = 0; i>spalette->nentries; i++)
+   {
+      if (spalette->depth == 8)
+      {
+         entrybuf[0] = (png_byte)ep[i].red;
+         entrybuf[1] = (png_byte)ep[i].green;
+         entrybuf[2] = (png_byte)ep[i].blue;
+         entrybuf[3] = (png_byte)ep[i].alpha;
+         png_save_uint_16(entrybuf + 4, ep[i].frequency);
+      }
+
+      else
+      {
+         png_save_uint_16(entrybuf + 0, ep[i].red);
+         png_save_uint_16(entrybuf + 2, ep[i].green);
+         png_save_uint_16(entrybuf + 4, ep[i].blue);
+         png_save_uint_16(entrybuf + 6, ep[i].alpha);
+         png_save_uint_16(entrybuf + 8, ep[i].frequency);
+      }
+
+      png_write_chunk_data(png_ptr, entrybuf, entry_size);
+   }
+#endif
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+/* Write the sBIT chunk */
+void /* PRIVATE */
+png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
+{
+   png_byte buf[4];
+   size_t size;
+
+   png_debug(1, "in png_write_sBIT");
+
+   /* Make sure we don't depend upon the order of PNG_COLOR_8 */
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_byte maxbits;
+
+      maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
+          png_ptr->usr_bit_depth);
+
+      if (sbit->red == 0 || sbit->red > maxbits ||
+          sbit->green == 0 || sbit->green > maxbits ||
+          sbit->blue == 0 || sbit->blue > maxbits)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
+
+      buf[0] = sbit->red;
+      buf[1] = sbit->green;
+      buf[2] = sbit->blue;
+      size = 3;
+   }
+
+   else
+   {
+      if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
+
+      buf[0] = sbit->gray;
+      size = 1;
+   }
+
+   if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
+   {
+      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
+
+      buf[size++] = sbit->alpha;
+   }
+
+   png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
+}
+#endif
+
+#ifdef PNG_WRITE_cHRM_SUPPORTED
+/* Write the cHRM chunk */
+void /* PRIVATE */
+png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy)
+{
+   png_byte buf[32];
+
+   png_debug(1, "in png_write_cHRM");
+
+   /* Each value is saved in 1/100,000ths */
+   png_save_int_32(buf,      xy->whitex);
+   png_save_int_32(buf +  4, xy->whitey);
+
+   png_save_int_32(buf +  8, xy->redx);
+   png_save_int_32(buf + 12, xy->redy);
+
+   png_save_int_32(buf + 16, xy->greenx);
+   png_save_int_32(buf + 20, xy->greeny);
+
+   png_save_int_32(buf + 24, xy->bluex);
+   png_save_int_32(buf + 28, xy->bluey);
+
+   png_write_complete_chunk(png_ptr, png_cHRM, buf, 32);
+}
+#endif
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+/* Write the tRNS chunk */
+void /* PRIVATE */
+png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
+    png_const_color_16p tran, int num_trans, int color_type)
+{
+   png_byte buf[6];
+
+   png_debug(1, "in png_write_tRNS");
+
+   if (color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
+      {
+         png_app_warning(png_ptr,
+             "Invalid number of transparent colors specified");
+         return;
+      }
+
+      /* Write the chunk out as it is */
+      png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
+          (size_t)num_trans);
+   }
+
+   else if (color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      /* One 16-bit value */
+      if (tran->gray >= (1 << png_ptr->bit_depth))
+      {
+         png_app_warning(png_ptr,
+             "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
+
+         return;
+      }
+
+      png_save_uint_16(buf, tran->gray);
+      png_write_complete_chunk(png_ptr, png_tRNS, buf, 2);
+   }
+
+   else if (color_type == PNG_COLOR_TYPE_RGB)
+   {
+      /* Three 16-bit values */
+      png_save_uint_16(buf, tran->red);
+      png_save_uint_16(buf + 2, tran->green);
+      png_save_uint_16(buf + 4, tran->blue);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
+#else
+      if ((buf[0] | buf[2] | buf[4]) != 0)
+#endif
+      {
+         png_app_warning(png_ptr,
+             "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
+         return;
+      }
+
+      png_write_complete_chunk(png_ptr, png_tRNS, buf, 6);
+   }
+
+   else
+   {
+      png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+/* Write the background chunk */
+void /* PRIVATE */
+png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
+{
+   png_byte buf[6];
+
+   png_debug(1, "in png_write_bKGD");
+
+   if (color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+          (png_ptr->num_palette != 0 ||
+          (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
+#endif
+         back->index >= png_ptr->num_palette)
+      {
+         png_warning(png_ptr, "Invalid background palette index");
+         return;
+      }
+
+      buf[0] = back->index;
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, 1);
+   }
+
+   else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_save_uint_16(buf, back->red);
+      png_save_uint_16(buf + 2, back->green);
+      png_save_uint_16(buf + 4, back->blue);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
+#else
+      if ((buf[0] | buf[2] | buf[4]) != 0)
+#endif
+      {
+         png_warning(png_ptr,
+             "Ignoring attempt to write 16-bit bKGD chunk "
+             "when bit_depth is 8");
+
+         return;
+      }
+
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, 6);
+   }
+
+   else
+   {
+      if (back->gray >= (1 << png_ptr->bit_depth))
+      {
+         png_warning(png_ptr,
+             "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
+
+         return;
+      }
+
+      png_save_uint_16(buf, back->gray);
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, 2);
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_eXIf_SUPPORTED
+/* Write the Exif data */
+void /* PRIVATE */
+png_write_eXIf(png_structrp png_ptr, png_bytep exif, int num_exif)
+{
+   int i;
+   png_byte buf[1];
+
+   png_debug(1, "in png_write_eXIf");
+
+   png_write_chunk_header(png_ptr, png_eXIf, (png_uint_32)(num_exif));
+
+   for (i = 0; i < num_exif; i++)
+   {
+      buf[0] = exif[i];
+      png_write_chunk_data(png_ptr, buf, 1);
+   }
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+/* Write the histogram */
+void /* PRIVATE */
+png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)
+{
+   int i;
+   png_byte buf[3];
+
+   png_debug(1, "in png_write_hIST");
+
+   if (num_hist > (int)png_ptr->num_palette)
+   {
+      png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
+          png_ptr->num_palette);
+
+      png_warning(png_ptr, "Invalid number of histogram entries specified");
+      return;
+   }
+
+   png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
+
+   for (i = 0; i < num_hist; i++)
+   {
+      png_save_uint_16(buf, hist[i]);
+      png_write_chunk_data(png_ptr, buf, 2);
+   }
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+/* Write a tEXt chunk */
+void /* PRIVATE */
+png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
+    size_t text_len)
+{
+   png_uint_32 key_len;
+   png_byte new_key[80];
+
+   png_debug(1, "in png_write_tEXt");
+
+   key_len = png_check_keyword(png_ptr, key, new_key);
+
+   if (key_len == 0)
+      png_error(png_ptr, "tEXt: invalid keyword");
+
+   if (text == NULL || *text == '\0')
+      text_len = 0;
+
+   else
+      text_len = strlen(text);
+
+   if (text_len > PNG_UINT_31_MAX - (key_len+1))
+      png_error(png_ptr, "tEXt: text too long");
+
+   /* Make sure we include the 0 after the key */
+   png_write_chunk_header(png_ptr, png_tEXt,
+       (png_uint_32)/*checked above*/(key_len + text_len + 1));
+   /*
+    * We leave it to the application to meet PNG-1.0 requirements on the
+    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
+    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
+    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+    */
+   png_write_chunk_data(png_ptr, new_key, key_len + 1);
+
+   if (text_len != 0)
+      png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+/* Write a compressed text chunk */
+void /* PRIVATE */
+png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
+    int compression)
+{
+   png_uint_32 key_len;
+   png_byte new_key[81];
+   compression_state comp;
+
+   png_debug(1, "in png_write_zTXt");
+
+   if (compression == PNG_TEXT_COMPRESSION_NONE)
+   {
+      png_write_tEXt(png_ptr, key, text, 0);
+      return;
+   }
+
+   if (compression != PNG_TEXT_COMPRESSION_zTXt)
+      png_error(png_ptr, "zTXt: invalid compression type");
+
+   key_len = png_check_keyword(png_ptr, key, new_key);
+
+   if (key_len == 0)
+      png_error(png_ptr, "zTXt: invalid keyword");
+
+   /* Add the compression method and 1 for the keyword separator. */
+   new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
+   ++key_len;
+
+   /* Compute the compressed data; do it now for the length */
+   png_text_compress_init(&comp, (png_const_bytep)text,
+       text == NULL ? 0 : strlen(text));
+
+   if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK)
+      png_error(png_ptr, png_ptr->zstream.msg);
+
+   /* Write start of chunk */
+   png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len);
+
+   /* Write key */
+   png_write_chunk_data(png_ptr, new_key, key_len);
+
+   /* Write the compressed data */
+   png_write_compressed_data_out(png_ptr, &comp);
+
+   /* Close the chunk */
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+/* Write an iTXt chunk */
+void /* PRIVATE */
+png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
+    png_const_charp lang, png_const_charp lang_key, png_const_charp text)
+{
+   png_uint_32 key_len, prefix_len;
+   size_t lang_len, lang_key_len;
+   png_byte new_key[82];
+   compression_state comp;
+
+   png_debug(1, "in png_write_iTXt");
+
+   key_len = png_check_keyword(png_ptr, key, new_key);
+
+   if (key_len == 0)
+      png_error(png_ptr, "iTXt: invalid keyword");
+
+   /* Set the compression flag */
+   switch (compression)
+   {
+      case PNG_ITXT_COMPRESSION_NONE:
+      case PNG_TEXT_COMPRESSION_NONE:
+         compression = new_key[++key_len] = 0; /* no compression */
+         break;
+
+      case PNG_TEXT_COMPRESSION_zTXt:
+      case PNG_ITXT_COMPRESSION_zTXt:
+         compression = new_key[++key_len] = 1; /* compressed */
+         break;
+
+      default:
+         png_error(png_ptr, "iTXt: invalid compression");
+   }
+
+   new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
+   ++key_len; /* for the keywod separator */
+
+   /* We leave it to the application to meet PNG-1.0 requirements on the
+    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
+    * any non-Latin-1 characters except for NEWLINE.  ISO PNG, however,
+    * specifies that the text is UTF-8 and this really doesn't require any
+    * checking.
+    *
+    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+    *
+    * TODO: validate the language tag correctly (see the spec.)
+    */
+   if (lang == NULL) lang = ""; /* empty language is valid */
+   lang_len = strlen(lang)+1;
+   if (lang_key == NULL) lang_key = ""; /* may be empty */
+   lang_key_len = strlen(lang_key)+1;
+   if (text == NULL) text = ""; /* may be empty */
+
+   prefix_len = key_len;
+   if (lang_len > PNG_UINT_31_MAX-prefix_len)
+      prefix_len = PNG_UINT_31_MAX;
+   else
+      prefix_len = (png_uint_32)(prefix_len + lang_len);
+
+   if (lang_key_len > PNG_UINT_31_MAX-prefix_len)
+      prefix_len = PNG_UINT_31_MAX;
+   else
+      prefix_len = (png_uint_32)(prefix_len + lang_key_len);
+
+   png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));
+
+   if (compression != 0)
+   {
+      if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)
+         png_error(png_ptr, png_ptr->zstream.msg);
+   }
+
+   else
+   {
+      if (comp.input_len > PNG_UINT_31_MAX-prefix_len)
+         png_error(png_ptr, "iTXt: uncompressed text too long");
+
+      /* So the string will fit in a chunk: */
+      comp.output_len = (png_uint_32)/*SAFE*/comp.input_len;
+   }
+
+   png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len);
+
+   png_write_chunk_data(png_ptr, new_key, key_len);
+
+   png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len);
+
+   png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);
+
+   if (compression != 0)
+      png_write_compressed_data_out(png_ptr, &comp);
+
+   else
+      png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.output_len);
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+/* Write the oFFs chunk */
+void /* PRIVATE */
+png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
+    int unit_type)
+{
+   png_byte buf[9];
+
+   png_debug(1, "in png_write_oFFs");
+
+   if (unit_type >= PNG_OFFSET_LAST)
+      png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
+
+   png_save_int_32(buf, x_offset);
+   png_save_int_32(buf + 4, y_offset);
+   buf[8] = (png_byte)unit_type;
+
+   png_write_complete_chunk(png_ptr, png_oFFs, buf, 9);
+}
+#endif
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+/* Write the pCAL chunk (described in the PNG extensions document) */
+void /* PRIVATE */
+png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
+    png_int_32 X1, int type, int nparams, png_const_charp units,
+    png_charpp params)
+{
+   png_uint_32 purpose_len;
+   size_t units_len, total_len;
+   png_size_tp params_len;
+   png_byte buf[10];
+   png_byte new_purpose[80];
+   int i;
+
+   png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
+
+   if (type >= PNG_EQUATION_LAST)
+      png_error(png_ptr, "Unrecognized equation type for pCAL chunk");
+
+   purpose_len = png_check_keyword(png_ptr, purpose, new_purpose);
+
+   if (purpose_len == 0)
+      png_error(png_ptr, "pCAL: invalid keyword");
+
+   ++purpose_len; /* terminator */
+
+   png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
+   units_len = strlen(units) + (nparams == 0 ? 0 : 1);
+   png_debug1(3, "pCAL units length = %d", (int)units_len);
+   total_len = purpose_len + units_len + 10;
+
+   params_len = (png_size_tp)png_malloc(png_ptr,
+       (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (size_t))));
+
+   /* Find the length of each parameter, making sure we don't count the
+    * null terminator for the last parameter.
+    */
+   for (i = 0; i < nparams; i++)
+   {
+      params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
+      png_debug2(3, "pCAL parameter %d length = %lu", i,
+          (unsigned long)params_len[i]);
+      total_len += params_len[i];
+   }
+
+   png_debug1(3, "pCAL total length = %d", (int)total_len);
+   png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
+   png_write_chunk_data(png_ptr, new_purpose, purpose_len);
+   png_save_int_32(buf, X0);
+   png_save_int_32(buf + 4, X1);
+   buf[8] = (png_byte)type;
+   buf[9] = (png_byte)nparams;
+   png_write_chunk_data(png_ptr, buf, 10);
+   png_write_chunk_data(png_ptr, (png_const_bytep)units, (size_t)units_len);
+
+   for (i = 0; i < nparams; i++)
+   {
+      png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
+   }
+
+   png_free(png_ptr, params_len);
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+/* Write the sCAL chunk */
+void /* PRIVATE */
+png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,
+    png_const_charp height)
+{
+   png_byte buf[64];
+   size_t wlen, hlen, total_len;
+
+   png_debug(1, "in png_write_sCAL_s");
+
+   wlen = strlen(width);
+   hlen = strlen(height);
+   total_len = wlen + hlen + 2;
+
+   if (total_len > 64)
+   {
+      png_warning(png_ptr, "Can't write sCAL (buffer too small)");
+      return;
+   }
+
+   buf[0] = (png_byte)unit;
+   memcpy(buf + 1, width, wlen + 1);      /* Append the '\0' here */
+   memcpy(buf + wlen + 2, height, hlen);  /* Do NOT append the '\0' here */
+
+   png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
+   png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
+}
+#endif
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+/* Write the pHYs chunk */
+void /* PRIVATE */
+png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit,
+    png_uint_32 y_pixels_per_unit,
+    int unit_type)
+{
+   png_byte buf[9];
+
+   png_debug(1, "in png_write_pHYs");
+
+   if (unit_type >= PNG_RESOLUTION_LAST)
+      png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
+
+   png_save_uint_32(buf, x_pixels_per_unit);
+   png_save_uint_32(buf + 4, y_pixels_per_unit);
+   buf[8] = (png_byte)unit_type;
+
+   png_write_complete_chunk(png_ptr, png_pHYs, buf, 9);
+}
+#endif
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+/* Write the tIME chunk.  Use either png_convert_from_struct_tm()
+ * or png_convert_from_time_t(), or fill in the structure yourself.
+ */
+void /* PRIVATE */
+png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)
+{
+   png_byte buf[7];
+
+   png_debug(1, "in png_write_tIME");
+
+   if (mod_time->month  > 12 || mod_time->month  < 1 ||
+       mod_time->day    > 31 || mod_time->day    < 1 ||
+       mod_time->hour   > 23 || mod_time->second > 60)
+   {
+      png_warning(png_ptr, "Invalid time specified for tIME chunk");
+      return;
+   }
+
+   png_save_uint_16(buf, mod_time->year);
+   buf[2] = mod_time->month;
+   buf[3] = mod_time->day;
+   buf[4] = mod_time->hour;
+   buf[5] = mod_time->minute;
+   buf[6] = mod_time->second;
+
+   png_write_complete_chunk(png_ptr, png_tIME, buf, 7);
+}
+#endif
+
+/* Initializes the row writing capability of libpng */
+void /* PRIVATE */
+png_write_start_row(png_structrp png_ptr)
+{
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+   png_alloc_size_t buf_size;
+   int usr_pixel_depth;
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   png_byte filters;
+#endif
+
+   png_debug(1, "in png_write_start_row");
+
+   usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
+   buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
+
+   /* 1.5.6: added to allow checking in the row write code. */
+   png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
+   png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
+
+   /* Set up row buffer */
+   png_ptr->row_buf = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
+
+   png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   filters = png_ptr->do_filter;
+
+   if (png_ptr->height == 1)
+      filters &= 0xff & ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+   if (png_ptr->width == 1)
+      filters &= 0xff & ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+   if (filters == 0)
+      filters = PNG_FILTER_NONE;
+
+   png_ptr->do_filter = filters;
+
+   if (((filters & (PNG_FILTER_SUB | PNG_FILTER_UP | PNG_FILTER_AVG |
+       PNG_FILTER_PAETH)) != 0) && png_ptr->try_row == NULL)
+   {
+      int num_filters = 0;
+
+      png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
+
+      if (filters & PNG_FILTER_SUB)
+         num_filters++;
+
+      if (filters & PNG_FILTER_UP)
+         num_filters++;
+
+      if (filters & PNG_FILTER_AVG)
+         num_filters++;
+
+      if (filters & PNG_FILTER_PAETH)
+         num_filters++;
+
+      if (num_filters > 1)
+         png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr,
+             buf_size));
+   }
+
+   /* We only need to keep the previous row if we are using one of the following
+    * filters.
+    */
+   if ((filters & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
+      png_ptr->prev_row = png_voidcast(png_bytep,
+          png_calloc(png_ptr, buf_size));
+#endif /* WRITE_FILTER */
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* If interlaced, we need to set up width and height of pass */
+   if (png_ptr->interlaced != 0)
+   {
+      if ((png_ptr->transformations & PNG_INTERLACE) == 0)
+      {
+         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+             png_pass_ystart[0]) / png_pass_yinc[0];
+
+         png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
+             png_pass_start[0]) / png_pass_inc[0];
+      }
+
+      else
+      {
+         png_ptr->num_rows = png_ptr->height;
+         png_ptr->usr_width = png_ptr->width;
+      }
+   }
+
+   else
+#endif
+   {
+      png_ptr->num_rows = png_ptr->height;
+      png_ptr->usr_width = png_ptr->width;
+   }
+}
+
+/* Internal use only.  Called when finished processing a row of data. */
+void /* PRIVATE */
+png_write_finish_row(png_structrp png_ptr)
+{
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+   png_debug(1, "in png_write_finish_row");
+
+   /* Next row */
+   png_ptr->row_number++;
+
+   /* See if we are done */
+   if (png_ptr->row_number < png_ptr->num_rows)
+      return;
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* If interlaced, go to next pass */
+   if (png_ptr->interlaced != 0)
+   {
+      png_ptr->row_number = 0;
+      if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+      {
+         png_ptr->pass++;
+      }
+
+      else
+      {
+         /* Loop until we find a non-zero width or height pass */
+         do
+         {
+            png_ptr->pass++;
+
+            if (png_ptr->pass >= 7)
+               break;
+
+            png_ptr->usr_width = (png_ptr->width +
+                png_pass_inc[png_ptr->pass] - 1 -
+                png_pass_start[png_ptr->pass]) /
+                png_pass_inc[png_ptr->pass];
+
+            png_ptr->num_rows = (png_ptr->height +
+                png_pass_yinc[png_ptr->pass] - 1 -
+                png_pass_ystart[png_ptr->pass]) /
+                png_pass_yinc[png_ptr->pass];
+
+            if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+               break;
+
+         } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
+
+      }
+
+      /* Reset the row above the image for the next pass */
+      if (png_ptr->pass < 7)
+      {
+         if (png_ptr->prev_row != NULL)
+            memset(png_ptr->prev_row, 0,
+                PNG_ROWBYTES(png_ptr->usr_channels *
+                png_ptr->usr_bit_depth, png_ptr->width) + 1);
+
+         return;
+      }
+   }
+#endif
+
+   /* If we get here, we've just written the last row, so we need
+      to flush the compressor */
+   png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH);
+}
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+/* Pick out the correct pixels for the interlace pass.
+ * The basic idea here is to go through the row with a source
+ * pointer and a destination pointer (sp and dp), and copy the
+ * correct pixels for the pass.  As the row gets compacted,
+ * sp will always be >= dp, so we should never overwrite anything.
+ * See the default: case for the easiest code to understand.
+ */
+void /* PRIVATE */
+png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
+{
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   png_debug(1, "in png_do_write_interlace");
+
+   /* We don't have to do anything on the last pass (6) */
+   if (pass < 6)
+   {
+      /* Each pixel depth is handled separately */
+      switch (row_info->pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            unsigned int shift;
+            int d;
+            int value;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            dp = row;
+            d = 0;
+            shift = 7;
+
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               sp = row + (size_t)(i >> 3);
+               value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
+               d |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 7;
+                  *dp++ = (png_byte)d;
+                  d = 0;
+               }
+
+               else
+                  shift--;
+
+            }
+            if (shift != 7)
+               *dp = (png_byte)d;
+
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            unsigned int shift;
+            int d;
+            int value;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            dp = row;
+            shift = 6;
+            d = 0;
+
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               sp = row + (size_t)(i >> 2);
+               value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
+               d |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 6;
+                  *dp++ = (png_byte)d;
+                  d = 0;
+               }
+
+               else
+                  shift -= 2;
+            }
+            if (shift != 6)
+               *dp = (png_byte)d;
+
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            unsigned int shift;
+            int d;
+            int value;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            dp = row;
+            shift = 4;
+            d = 0;
+            for (i = png_pass_start[pass]; i < row_width;
+                i += png_pass_inc[pass])
+            {
+               sp = row + (size_t)(i >> 1);
+               value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
+               d |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 4;
+                  *dp++ = (png_byte)d;
+                  d = 0;
+               }
+
+               else
+                  shift -= 4;
+            }
+            if (shift != 4)
+               *dp = (png_byte)d;
+
+            break;
+         }
+
+         default:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+            size_t pixel_bytes;
+
+            /* Start at the beginning */
+            dp = row;
+
+            /* Find out how many bytes each pixel takes up */
+            pixel_bytes = (row_info->pixel_depth >> 3);
+
+            /* Loop through the row, only looking at the pixels that matter */
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               /* Find out where the original pixel is */
+               sp = row + (size_t)i * pixel_bytes;
+
+               /* Move the pixel */
+               if (dp != sp)
+                  memcpy(dp, sp, pixel_bytes);
+
+               /* Next pixel */
+               dp += pixel_bytes;
+            }
+            break;
+         }
+      }
+      /* Set new row width */
+      row_info->width = (row_info->width +
+          png_pass_inc[pass] - 1 -
+          png_pass_start[pass]) /
+          png_pass_inc[pass];
+
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+          row_info->width);
+   }
+}
+#endif
+
+
+/* This filters the row, chooses which filter to use, if it has not already
+ * been specified by the application, and then writes the row out with the
+ * chosen filter.
+ */
+static void /* PRIVATE */
+png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
+    size_t row_bytes);
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+static size_t /* PRIVATE */
+png_setup_sub_row(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes, size_t lmins)
+{
+   png_bytep rp, dp, lp;
+   size_t i;
+   size_t sum = 0;
+   unsigned int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
+        i++, rp++, dp++)
+   {
+      v = *dp = *rp;
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes;
+      i++, rp++, lp++, dp++)
+   {
+      v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return (sum);
+}
+
+static void /* PRIVATE */
+png_setup_sub_row_only(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes)
+{
+   png_bytep rp, dp, lp;
+   size_t i;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
+        i++, rp++, dp++)
+   {
+      *dp = *rp;
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes;
+      i++, rp++, lp++, dp++)
+   {
+      *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+   }
+}
+
+static size_t /* PRIVATE */
+png_setup_up_row(png_structrp png_ptr, size_t row_bytes, size_t lmins)
+{
+   png_bytep rp, dp, pp;
+   size_t i;
+   size_t sum = 0;
+   unsigned int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < row_bytes;
+       i++, rp++, pp++, dp++)
+   {
+      v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return (sum);
+}
+static void /* PRIVATE */
+png_setup_up_row_only(png_structrp png_ptr, size_t row_bytes)
+{
+   png_bytep rp, dp, pp;
+   size_t i;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < row_bytes;
+       i++, rp++, pp++, dp++)
+   {
+      *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+   }
+}
+
+static size_t /* PRIVATE */
+png_setup_avg_row(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes, size_t lmins)
+{
+   png_bytep rp, dp, pp, lp;
+   png_uint_32 i;
+   size_t sum = 0;
+   unsigned int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
+   {
+      v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+          & 0xff);
+
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return (sum);
+}
+static void /* PRIVATE */
+png_setup_avg_row_only(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes)
+{
+   png_bytep rp, dp, pp, lp;
+   png_uint_32 i;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
+   {
+      *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+          & 0xff);
+   }
+}
+
+static size_t /* PRIVATE */
+png_setup_paeth_row(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes, size_t lmins)
+{
+   png_bytep rp, dp, pp, cp, lp;
+   size_t i;
+   size_t sum = 0;
+   unsigned int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+   }
+
+   for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
+        i++)
+   {
+      int a, b, c, pa, pb, pc, p;
+
+      b = *pp++;
+      c = *cp++;
+      a = *lp++;
+
+      p = b - c;
+      pc = a - c;
+
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+      p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+      v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return (sum);
+}
+static void /* PRIVATE */
+png_setup_paeth_row_only(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes)
+{
+   png_bytep rp, dp, pp, cp, lp;
+   size_t i;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+   }
+
+   for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
+        i++)
+   {
+      int a, b, c, pa, pb, pc, p;
+
+      b = *pp++;
+      c = *cp++;
+      a = *lp++;
+
+      p = b - c;
+      pc = a - c;
+
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+      p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+      *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+   }
+}
+#endif /* WRITE_FILTER */
+
+void /* PRIVATE */
+png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
+{
+#ifndef PNG_WRITE_FILTER_SUPPORTED
+   png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
+#else
+   unsigned int filter_to_do = png_ptr->do_filter;
+   png_bytep row_buf;
+   png_bytep best_row;
+   png_uint_32 bpp;
+   size_t mins;
+   size_t row_bytes = row_info->rowbytes;
+
+   png_debug(1, "in png_write_find_filter");
+
+   /* Find out how many bytes offset each pixel is */
+   bpp = (row_info->pixel_depth + 7) >> 3;
+
+   row_buf = png_ptr->row_buf;
+   mins = PNG_SIZE_MAX - 256/* so we can detect potential overflow of the
+                               running sum */;
+
+   /* The prediction method we use is to find which method provides the
+    * smallest value when summing the absolute values of the distances
+    * from zero, using anything >= 128 as negative numbers.  This is known
+    * as the "minimum sum of absolute differences" heuristic.  Other
+    * heuristics are the "weighted minimum sum of absolute differences"
+    * (experimental and can in theory improve compression), and the "zlib
+    * predictive" method (not implemented yet), which does test compressions
+    * of lines using different filter methods, and then chooses the
+    * (series of) filter(s) that give minimum compressed data size (VERY
+    * computationally expensive).
+    *
+    * GRR 980525:  consider also
+    *
+    *   (1) minimum sum of absolute differences from running average (i.e.,
+    *       keep running sum of non-absolute differences & count of bytes)
+    *       [track dispersion, too?  restart average if dispersion too large?]
+    *
+    *  (1b) minimum sum of absolute differences from sliding average, probably
+    *       with window size <= deflate window (usually 32K)
+    *
+    *   (2) minimum sum of squared differences from zero or running average
+    *       (i.e., ~ root-mean-square approach)
+    */
+
+
+   /* We don't need to test the 'no filter' case if this is the only filter
+    * that has been chosen, as it doesn't actually do anything to the data.
+    */
+   best_row = png_ptr->row_buf;
+
+   if (PNG_SIZE_MAX/128 <= row_bytes)
+   {
+      /* Overflow can occur in the calculation, just select the lowest set
+       * filter.
+       */
+      filter_to_do &= 0U-filter_to_do;
+   }
+   else if ((filter_to_do & PNG_FILTER_NONE) != 0 &&
+         filter_to_do != PNG_FILTER_NONE)
+   {
+      /* Overflow not possible and multiple filters in the list, including the
+       * 'none' filter.
+       */
+      png_bytep rp;
+      size_t sum = 0;
+      size_t i;
+      unsigned int v;
+
+      {
+         for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
+         {
+            v = *rp;
+#ifdef PNG_USE_ABS
+            sum += 128 - abs((int)v - 128);
+#else
+            sum += (v < 128) ? v : 256 - v;
+#endif
+         }
+      }
+
+      mins = sum;
+   }
+
+   /* Sub filter */
+   if (filter_to_do == PNG_FILTER_SUB)
+   /* It's the only filter so no testing is needed */
+   {
+      png_setup_sub_row_only(png_ptr, bpp, row_bytes);
+      best_row = png_ptr->try_row;
+   }
+
+   else if ((filter_to_do & PNG_FILTER_SUB) != 0)
+   {
+      size_t sum;
+      size_t lmins = mins;
+
+      sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins);
+
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
+      }
+   }
+
+   /* Up filter */
+   if (filter_to_do == PNG_FILTER_UP)
+   {
+      png_setup_up_row_only(png_ptr, row_bytes);
+      best_row = png_ptr->try_row;
+   }
+
+   else if ((filter_to_do & PNG_FILTER_UP) != 0)
+   {
+      size_t sum;
+      size_t lmins = mins;
+
+      sum = png_setup_up_row(png_ptr, row_bytes, lmins);
+
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
+      }
+   }
+
+   /* Avg filter */
+   if (filter_to_do == PNG_FILTER_AVG)
+   {
+      png_setup_avg_row_only(png_ptr, bpp, row_bytes);
+      best_row = png_ptr->try_row;
+   }
+
+   else if ((filter_to_do & PNG_FILTER_AVG) != 0)
+   {
+      size_t sum;
+      size_t lmins = mins;
+
+      sum= png_setup_avg_row(png_ptr, bpp, row_bytes, lmins);
+
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
+      }
+   }
+
+   /* Paeth filter */
+   if (filter_to_do == PNG_FILTER_PAETH)
+   {
+      png_setup_paeth_row_only(png_ptr, bpp, row_bytes);
+      best_row = png_ptr->try_row;
+   }
+
+   else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
+   {
+      size_t sum;
+      size_t lmins = mins;
+
+      sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins);
+
+      if (sum < mins)
+      {
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
+      }
+   }
+
+   /* Do the actual writing of the filtered row data from the chosen filter. */
+   png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
+
+#endif /* WRITE_FILTER */
+}
+
+
+/* Do the actual writing of a previously filtered row. */
+static void
+png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
+    size_t full_row_length/*includes filter byte*/)
+{
+   png_debug(1, "in png_write_filtered_row");
+
+   png_debug1(2, "filter = %d", filtered_row[0]);
+
+   png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   /* Swap the current and previous rows */
+   if (png_ptr->prev_row != NULL)
+   {
+      png_bytep tptr;
+
+      tptr = png_ptr->prev_row;
+      png_ptr->prev_row = png_ptr->row_buf;
+      png_ptr->row_buf = tptr;
+   }
+#endif /* WRITE_FILTER */
+
+   /* Finish row - updates counters and flushes zlib if last row */
+   png_write_finish_row(png_ptr);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+   png_ptr->flush_rows++;
+
+   if (png_ptr->flush_dist > 0 &&
+       png_ptr->flush_rows >= png_ptr->flush_dist)
+   {
+      png_write_flush(png_ptr);
+   }
+#endif /* WRITE_FLUSH */
+}
+#endif /* WRITE */
diff --git a/extern/libpng/powerpc/filter_vsx_intrinsics.c b/extern/libpng/powerpc/filter_vsx_intrinsics.c
new file mode 100644
index 0000000000..01cf8800dc
--- /dev/null
+++ b/extern/libpng/powerpc/filter_vsx_intrinsics.c
@@ -0,0 +1,768 @@
+/* filter_vsx_intrinsics.c - PowerPC optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2017 Glenn Randers-Pehrson
+ * Written by Vadim Barkov, 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* This code requires -maltivec and -mvsx on the command line: */
+#if PNG_POWERPC_VSX_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+#include <altivec.h>
+
+#if PNG_POWERPC_VSX_OPT > 0
+
+#ifndef __VSX__
+#  error "This code requires VSX support (POWER7 and later). Please provide -mvsx compiler flag."
+#endif
+
+#define vec_ld_unaligned(vec,data) vec = vec_vsx_ld(0,data)
+#define vec_st_unaligned(vec,data) vec_vsx_st(vec,0,data)
+
+
+/* Functions in this file look at most 3 pixels (a,b,c) to predict the 4th (d).
+ * They're positioned like this:
+ *    prev:  c b
+ *    row:   a d
+ * The Sub filter predicts d=a, Avg d=(a+b)/2, and Paeth predicts d to be
+ * whichever of a, b, or c is closest to p=a+b-c.
+ * ( this is taken from ../intel/filter_sse2_intrinsics.c )
+ */
+
+#define vsx_declare_common_vars(row_info,row,prev_row,offset) \
+   png_byte i;\
+   png_bytep rp = row + offset;\
+   png_const_bytep pp = prev_row;\
+   size_t unaligned_top = 16 - (((size_t)rp % 16));\
+   size_t istop;\
+   if(unaligned_top == 16)\
+      unaligned_top = 0;\
+   istop = row_info->rowbytes;\
+   if((unaligned_top < istop))\
+      istop -= unaligned_top;\
+   else{\
+      unaligned_top = istop;\
+      istop = 0;\
+   }
+
+void png_read_filter_row_up_vsx(png_row_infop row_info, png_bytep row,
+                                png_const_bytep prev_row)
+{
+   vector unsigned char rp_vec;
+   vector unsigned char pp_vec;
+   vsx_declare_common_vars(row_info,row,prev_row,0)
+
+   /* Altivec operations require 16-byte aligned data
+    * but input can be unaligned. So we calculate
+    * unaligned part as usual.
+    */
+   for (i = 0; i < unaligned_top; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+      rp++;
+   }
+
+   /* Using SIMD while we can */
+   while( istop >= 16 )
+   {
+      rp_vec = vec_ld(0,rp);
+      vec_ld_unaligned(pp_vec,pp);
+
+      rp_vec = vec_add(rp_vec,pp_vec);
+
+      vec_st(rp_vec,0,rp);
+
+      pp += 16;
+      rp += 16;
+      istop -= 16;
+   }
+
+   if(istop > 0)
+   {
+      /* If byte count of row is not divisible by 16
+       * we will process remaining part as usual
+       */
+      for (i = 0; i < istop; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+         rp++;
+      }
+}
+
+}
+
+static const vector unsigned char VSX_LEFTSHIFTED1_4 = {16,16,16,16, 0, 1, 2, 3,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED2_4 = {16,16,16,16,16,16,16,16, 4, 5, 6, 7,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED3_4 = {16,16,16,16,16,16,16,16,16,16,16,16, 8, 9,10,11};
+
+static const vector unsigned char VSX_LEFTSHIFTED1_3 = {16,16,16, 0, 1, 2,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED2_3 = {16,16,16,16,16,16, 3, 4, 5,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED3_3 = {16,16,16,16,16,16,16,16,16, 6, 7, 8,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED4_3 = {16,16,16,16,16,16,16,16,16,16,16,16, 9,10,11,16};
+
+static const vector unsigned char VSX_NOT_SHIFTED1_4 = {16,16,16,16, 4, 5, 6, 7,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED2_4 = {16,16,16,16,16,16,16,16, 8, 9,10,11,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED3_4 = {16,16,16,16,16,16,16,16,16,16,16,16,12,13,14,15};
+
+static const vector unsigned char VSX_NOT_SHIFTED1_3 = {16,16,16, 3, 4, 5,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED2_3 = {16,16,16,16,16,16, 6, 7, 8,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED3_3 = {16,16,16,16,16,16,16,16,16, 9,10,11,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED4_3 = {16,16,16,16,16,16,16,16,16,16,16,16,12,13,14,16};
+
+static const vector unsigned char VSX_CHAR_ZERO = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+#ifdef __LITTLE_ENDIAN__
+
+static const vector unsigned char VSX_CHAR_TO_SHORT1_4 = { 4,16, 5,16, 6,16, 7,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT2_4 = { 8,16, 9,16,10,16,11,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT3_4 = {12,16,13,16,14,16,15,16,16,16,16,16,16,16,16,16};
+
+static const vector unsigned char VSX_SHORT_TO_CHAR1_4 = {16,16,16,16, 0, 2, 4, 6,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR2_4 = {16,16,16,16,16,16,16,16, 0, 2, 4, 6,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR3_4 = {16,16,16,16,16,16,16,16,16,16,16,16, 0, 2, 4, 6};
+
+static const vector unsigned char VSX_CHAR_TO_SHORT1_3 = { 3,16, 4,16, 5,16,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT2_3 = { 6,16, 7,16, 8,16,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT3_3 = { 9,16,10,16,11,16,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT4_3 = {12,16,13,16,14,16,16,16,16,16,16,16,16,16,16,16};
+
+static const vector unsigned char VSX_SHORT_TO_CHAR1_3 = {16,16,16, 0, 2, 4,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR2_3 = {16,16,16,16,16,16, 0, 2, 4,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR3_3 = {16,16,16,16,16,16,16,16,16, 0, 2, 4,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR4_3 = {16,16,16,16,16,16,16,16,16,16,16,16, 0, 2, 4,16};
+
+#elif defined(__BIG_ENDIAN__)
+
+static const vector unsigned char VSX_CHAR_TO_SHORT1_4 = {16, 4,16, 5,16, 6,16, 7,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT2_4 = {16, 8,16, 9,16,10,16,11,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT3_4 = {16,12,16,13,16,14,16,15,16,16,16,16,16,16,16,16};
+
+static const vector unsigned char VSX_SHORT_TO_CHAR1_4 = {16,16,16,16, 1, 3, 5, 7,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR2_4 = {16,16,16,16,16,16,16,16, 1, 3, 5, 7,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR3_4 = {16,16,16,16,16,16,16,16,16,16,16,16, 1, 3, 5, 7};
+
+static const vector unsigned char VSX_CHAR_TO_SHORT1_3 = {16, 3,16, 4,16, 5,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT2_3 = {16, 6,16, 7,16, 8,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT3_3 = {16, 9,16,10,16,11,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT4_3 = {16,12,16,13,16,14,16,16,16,16,16,16,16,16,16,16};
+
+static const vector unsigned char VSX_SHORT_TO_CHAR1_3 = {16,16,16, 1, 3, 5,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR2_3 = {16,16,16,16,16,16, 1, 3, 5,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR3_3 = {16,16,16,16,16,16,16,16,16, 1, 3, 5,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR4_3 = {16,16,16,16,16,16,16,16,16,16,16,16, 1, 3, 5,16};
+
+#endif
+
+#define vsx_char_to_short(vec,offset,bpp) (vector unsigned short)vec_perm((vec),VSX_CHAR_ZERO,VSX_CHAR_TO_SHORT##offset##_##bpp)
+#define vsx_short_to_char(vec,offset,bpp) vec_perm(((vector unsigned char)(vec)),VSX_CHAR_ZERO,VSX_SHORT_TO_CHAR##offset##_##bpp)
+
+#ifdef PNG_USE_ABS
+#  define vsx_abs(number) abs(number)
+#else
+#  define vsx_abs(number) (number > 0) ? (number) : -(number)
+#endif
+
+void png_read_filter_row_sub4_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   png_byte bpp = 4;
+
+   vector unsigned char rp_vec;
+   vector unsigned char part_vec;
+
+   vsx_declare_common_vars(row_info,row,prev_row,bpp)
+
+   PNG_UNUSED(pp)
+
+   /* Altivec operations require 16-byte aligned data
+    * but input can be unaligned. So we calculate
+    * unaligned part as usual.
+    */
+   for (i = 0; i < unaligned_top; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+      rp++;
+   }
+
+   /* Using SIMD while we can */
+   while( istop >= 16 )
+   {
+      for(i=0;i < bpp ; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+         rp++;
+      }
+      rp -= bpp;
+
+      rp_vec = vec_ld(0,rp);
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_4);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_4);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_4);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      vec_st(rp_vec,0,rp);
+
+      rp += 16;
+      istop -= 16;
+   }
+
+   if(istop > 0)
+      for (i = 0; i < istop % 16; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*(rp - bpp))) & 0xff);
+         rp++;
+      }
+
+}
+
+void png_read_filter_row_sub3_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   png_byte bpp = 3;
+
+   vector unsigned char rp_vec;
+   vector unsigned char part_vec;
+
+   vsx_declare_common_vars(row_info,row,prev_row,bpp)
+
+   PNG_UNUSED(pp)
+
+   /* Altivec operations require 16-byte aligned data
+    * but input can be unaligned. So we calculate
+    * unaligned part as usual.
+    */
+   for (i = 0; i < unaligned_top; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+      rp++;
+   }
+
+   /* Using SIMD while we can */
+   while( istop >= 16 )
+   {
+      for(i=0;i < bpp ; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+         rp++;
+      }
+      rp -= bpp;
+
+      rp_vec = vec_ld(0,rp);
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_3);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_3);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_3);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED4_3);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      vec_st(rp_vec,0,rp);
+      rp += 15;
+      istop -= 16;
+
+      /* Since 16 % bpp = 16 % 3 = 1, last element of array must
+       * be proceeded manually
+       */
+      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+      rp++;
+   }
+
+   if(istop > 0)
+      for (i = 0; i < istop % 16; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+         rp++;
+      }
+}
+
+void png_read_filter_row_avg4_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   png_byte bpp = 4;
+
+   vector unsigned char rp_vec;
+   vector unsigned char pp_vec;
+   vector unsigned char pp_part_vec;
+   vector unsigned char rp_part_vec;
+   vector unsigned char avg_vec;
+
+   vsx_declare_common_vars(row_info,row,prev_row,bpp)
+   rp -= bpp;
+   if(istop >= bpp)
+      istop -= bpp;
+
+   for (i = 0; i < bpp; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) +
+         ((int)(*pp++) / 2 )) & 0xff);
+
+      rp++;
+   }
+
+   /* Altivec operations require 16-byte aligned data
+    * but input can be unaligned. So we calculate
+    * unaligned part as usual.
+    */
+   for (i = 0; i < unaligned_top; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) +
+         (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+      rp++;
+   }
+
+   /* Using SIMD while we can */
+   while( istop >= 16 )
+   {
+      for(i=0;i < bpp ; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) +
+            (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+         rp++;
+      }
+      rp -= bpp;
+      pp -= bpp;
+
+      vec_ld_unaligned(pp_vec,pp);
+      rp_vec = vec_ld(0,rp);
+
+      rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_4);
+      pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED1_4);
+      avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+      avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+      rp_vec = vec_add(rp_vec,avg_vec);
+
+      rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_4);
+      pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED2_4);
+      avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+      avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+      rp_vec = vec_add(rp_vec,avg_vec);
+
+      rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_4);
+      pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED3_4);
+      avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+      avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+      rp_vec = vec_add(rp_vec,avg_vec);
+
+      vec_st(rp_vec,0,rp);
+
+      rp += 16;
+      pp += 16;
+      istop -= 16;
+   }
+
+   if(istop  > 0)
+      for (i = 0; i < istop % 16; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) +
+            (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+         rp++;
+      }
+}
+
+void png_read_filter_row_avg3_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+  png_byte bpp = 3;
+
+  vector unsigned char rp_vec;
+  vector unsigned char pp_vec;
+  vector unsigned char pp_part_vec;
+  vector unsigned char rp_part_vec;
+  vector unsigned char avg_vec;
+
+  vsx_declare_common_vars(row_info,row,prev_row,bpp)
+  rp -= bpp;
+  if(istop >= bpp)
+     istop -= bpp;
+
+  for (i = 0; i < bpp; i++)
+  {
+     *rp = (png_byte)(((int)(*rp) +
+        ((int)(*pp++) / 2 )) & 0xff);
+
+     rp++;
+  }
+
+  /* Altivec operations require 16-byte aligned data
+   * but input can be unaligned. So we calculate
+   * unaligned part as usual.
+   */
+  for (i = 0; i < unaligned_top; i++)
+  {
+     *rp = (png_byte)(((int)(*rp) +
+        (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+     rp++;
+  }
+
+  /* Using SIMD while we can */
+  while( istop >= 16 )
+  {
+     for(i=0;i < bpp ; i++)
+     {
+        *rp = (png_byte)(((int)(*rp) +
+           (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+        rp++;
+     }
+     rp -= bpp;
+     pp -= bpp;
+
+     vec_ld_unaligned(pp_vec,pp);
+     rp_vec = vec_ld(0,rp);
+
+     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_3);
+     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED1_3);
+     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+     rp_vec = vec_add(rp_vec,avg_vec);
+
+     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_3);
+     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED2_3);
+     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+     rp_vec = vec_add(rp_vec,avg_vec);
+
+     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_3);
+     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED3_3);
+     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+     rp_vec = vec_add(rp_vec,avg_vec);
+
+     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED4_3);
+     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED4_3);
+     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+     rp_vec = vec_add(rp_vec,avg_vec);
+
+     vec_st(rp_vec,0,rp);
+
+     rp += 15;
+     pp += 15;
+     istop -= 16;
+
+     /* Since 16 % bpp = 16 % 3 = 1, last element of array must
+      * be proceeded manually
+      */
+     *rp = (png_byte)(((int)(*rp) +
+        (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+     rp++;
+  }
+
+  if(istop  > 0)
+     for (i = 0; i < istop % 16; i++)
+     {
+        *rp = (png_byte)(((int)(*rp) +
+           (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+        rp++;
+     }
+}
+
+/* Bytewise c ? t : e. */
+#define if_then_else(c,t,e) vec_sel(e,t,c)
+
+#define vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp) {\
+      c = *(pp - bpp);\
+      a = *(rp - bpp);\
+      b = *pp++;\
+      p = b - c;\
+      pc = a - c;\
+      pa = vsx_abs(p);\
+      pb = vsx_abs(pc);\
+      pc = vsx_abs(p + pc);\
+      if (pb < pa) pa = pb, a = b;\
+      if (pc < pa) a = c;\
+      a += *rp;\
+      *rp++ = (png_byte)a;\
+      }
+
+void png_read_filter_row_paeth4_vsx(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_byte bpp = 4;
+
+   int a, b, c, pa, pb, pc, p;
+   vector unsigned char rp_vec;
+   vector unsigned char pp_vec;
+   vector unsigned short a_vec,b_vec,c_vec,nearest_vec;
+   vector signed short pa_vec,pb_vec,pc_vec,smallest_vec;
+
+   vsx_declare_common_vars(row_info,row,prev_row,bpp)
+   rp -= bpp;
+   if(istop >= bpp)
+      istop -= bpp;
+
+   /* Process the first pixel in the row completely (this is the same as 'up'
+    * because there is only one candidate predictor for the first row).
+    */
+   for(i = 0; i < bpp ; i++)
+   {
+      *rp = (png_byte)( *rp + *pp);
+      rp++;
+      pp++;
+   }
+
+   for(i = 0; i < unaligned_top ; i++)
+   {
+      vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+   }
+
+   while( istop >= 16)
+   {
+      for(i = 0; i < bpp ; i++)
+      {
+         vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+      }
+
+      rp -= bpp;
+      pp -= bpp;
+      rp_vec = vec_ld(0,rp);
+      vec_ld_unaligned(pp_vec,pp);
+
+      a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_4),1,4);
+      b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED1_4),1,4);
+      c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_4),1,4);
+      pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+      pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+      pc_vec = vec_add(pa_vec,pb_vec);
+      pa_vec = vec_abs(pa_vec);
+      pb_vec = vec_abs(pb_vec);
+      pc_vec = vec_abs(pc_vec);
+      smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+      nearest_vec =  if_then_else(
+            vec_cmpeq(pa_vec,smallest_vec),
+            a_vec,
+            if_then_else(
+              vec_cmpeq(pb_vec,smallest_vec),
+              b_vec,
+              c_vec
+              )
+            );
+      rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,1,4)));
+
+      a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_4),2,4);
+      b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED2_4),2,4);
+      c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_4),2,4);
+      pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+      pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+      pc_vec = vec_add(pa_vec,pb_vec);
+      pa_vec = vec_abs(pa_vec);
+      pb_vec = vec_abs(pb_vec);
+      pc_vec = vec_abs(pc_vec);
+      smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+      nearest_vec =  if_then_else(
+            vec_cmpeq(pa_vec,smallest_vec),
+            a_vec,
+            if_then_else(
+              vec_cmpeq(pb_vec,smallest_vec),
+              b_vec,
+              c_vec
+              )
+            );
+      rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,2,4)));
+
+      a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_4),3,4);
+      b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED3_4),3,4);
+      c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_4),3,4);
+      pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+      pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+      pc_vec = vec_add(pa_vec,pb_vec);
+      pa_vec = vec_abs(pa_vec);
+      pb_vec = vec_abs(pb_vec);
+      pc_vec = vec_abs(pc_vec);
+      smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+      nearest_vec =  if_then_else(
+            vec_cmpeq(pa_vec,smallest_vec),
+            a_vec,
+            if_then_else(
+              vec_cmpeq(pb_vec,smallest_vec),
+              b_vec,
+              c_vec
+              )
+            );
+      rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,3,4)));
+
+      vec_st(rp_vec,0,rp);
+
+      rp += 16;
+      pp += 16;
+      istop -= 16;
+   }
+
+   if(istop > 0)
+      for (i = 0; i < istop % 16; i++)
+      {
+         vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+      }
+}
+
+void png_read_filter_row_paeth3_vsx(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+  png_byte bpp = 3;
+
+  int a, b, c, pa, pb, pc, p;
+  vector unsigned char rp_vec;
+  vector unsigned char pp_vec;
+  vector unsigned short a_vec,b_vec,c_vec,nearest_vec;
+  vector signed short pa_vec,pb_vec,pc_vec,smallest_vec;
+
+  vsx_declare_common_vars(row_info,row,prev_row,bpp)
+  rp -= bpp;
+  if(istop >= bpp)
+     istop -= bpp;
+
+  /* Process the first pixel in the row completely (this is the same as 'up'
+   * because there is only one candidate predictor for the first row).
+   */
+  for(i = 0; i < bpp ; i++)
+  {
+     *rp = (png_byte)( *rp + *pp);
+     rp++;
+     pp++;
+  }
+
+  for(i = 0; i < unaligned_top ; i++)
+  {
+     vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+  }
+
+  while( istop >= 16)
+  {
+     for(i = 0; i < bpp ; i++)
+     {
+        vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+     }
+
+     rp -= bpp;
+     pp -= bpp;
+     rp_vec = vec_ld(0,rp);
+     vec_ld_unaligned(pp_vec,pp);
+
+     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_3),1,3);
+     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED1_3),1,3);
+     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_3),1,3);
+     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+     pc_vec = vec_add(pa_vec,pb_vec);
+     pa_vec = vec_abs(pa_vec);
+     pb_vec = vec_abs(pb_vec);
+     pc_vec = vec_abs(pc_vec);
+     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+     nearest_vec =  if_then_else(
+           vec_cmpeq(pa_vec,smallest_vec),
+           a_vec,
+           if_then_else(
+             vec_cmpeq(pb_vec,smallest_vec),
+             b_vec,
+             c_vec
+             )
+           );
+     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,1,3)));
+
+     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_3),2,3);
+     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED2_3),2,3);
+     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_3),2,3);
+     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+     pc_vec = vec_add(pa_vec,pb_vec);
+     pa_vec = vec_abs(pa_vec);
+     pb_vec = vec_abs(pb_vec);
+     pc_vec = vec_abs(pc_vec);
+     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+     nearest_vec =  if_then_else(
+           vec_cmpeq(pa_vec,smallest_vec),
+           a_vec,
+           if_then_else(
+             vec_cmpeq(pb_vec,smallest_vec),
+             b_vec,
+             c_vec
+             )
+           );
+     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,2,3)));
+
+     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_3),3,3);
+     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED3_3),3,3);
+     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_3),3,3);
+     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+     pc_vec = vec_add(pa_vec,pb_vec);
+     pa_vec = vec_abs(pa_vec);
+     pb_vec = vec_abs(pb_vec);
+     pc_vec = vec_abs(pc_vec);
+     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+     nearest_vec =  if_then_else(
+           vec_cmpeq(pa_vec,smallest_vec),
+           a_vec,
+           if_then_else(
+             vec_cmpeq(pb_vec,smallest_vec),
+             b_vec,
+             c_vec
+             )
+           );
+     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,3,3)));
+
+     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED4_3),4,3);
+     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED4_3),4,3);
+     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED4_3),4,3);
+     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+     pc_vec = vec_add(pa_vec,pb_vec);
+     pa_vec = vec_abs(pa_vec);
+     pb_vec = vec_abs(pb_vec);
+     pc_vec = vec_abs(pc_vec);
+     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+     nearest_vec =  if_then_else(
+           vec_cmpeq(pa_vec,smallest_vec),
+           a_vec,
+           if_then_else(
+             vec_cmpeq(pb_vec,smallest_vec),
+             b_vec,
+             c_vec
+             )
+           );
+     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,4,3)));
+
+     vec_st(rp_vec,0,rp);
+
+     rp += 15;
+     pp += 15;
+     istop -= 16;
+
+     /* Since 16 % bpp = 16 % 3 = 1, last element of array must
+      * be proceeded manually
+      */
+     vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+  }
+
+  if(istop > 0)
+     for (i = 0; i < istop % 16; i++)
+     {
+        vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+     }
+}
+
+#endif /* PNG_POWERPC_VSX_OPT > 0 */
+#endif /* PNG_POWERPC_VSX_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */
diff --git a/extern/libpng/powerpc/powerpc_init.c b/extern/libpng/powerpc/powerpc_init.c
new file mode 100644
index 0000000000..54426c558e
--- /dev/null
+++ b/extern/libpng/powerpc/powerpc_init.c
@@ -0,0 +1,126 @@
+
+/* powerpc_init.c - POWERPC optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2017 Glenn Randers-Pehrson
+ * Written by Vadim Barkov, 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
+ * called.
+ */
+#define _POSIX_SOURCE 1
+
+#include <stdio.h>
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_POWERPC_VSX_OPT > 0
+#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED /* Do run-time checks */
+/* WARNING: it is strongly recommended that you do not build libpng with
+ * run-time checks for CPU features if at all possible.  In the case of the PowerPC
+ * VSX instructions there is no processor-specific way of detecting the
+ * presence of the required support, therefore run-time detection is extremely
+ * OS specific.
+ *
+ * You may set the macro PNG_POWERPC_VSX_FILE to the file name of file containing
+ * a fragment of C source code which defines the png_have_vsx function.  There
+ * are a number of implementations in contrib/powerpc-vsx, but the only one that
+ * has partial support is contrib/powerpc-vsx/linux.c - a generic Linux
+ * implementation which reads /proc/cpufino.
+ */
+#ifndef PNG_POWERPC_VSX_FILE
+#  ifdef __linux__
+#     define  PNG_POWERPC_VSX_FILE "contrib/powerpc-vsx/linux_aux.c"
+#  endif
+#endif
+
+#ifdef PNG_POWERPC_VSX_FILE
+
+#include <signal.h> /* for sig_atomic_t */
+static int png_have_vsx(png_structp png_ptr);
+#include PNG_POWERPC_VSX_FILE
+
+#else  /* PNG_POWERPC_VSX_FILE */
+#  error "PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks"
+#endif /* PNG_POWERPC_VSX_FILE */
+#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
+
+void
+png_init_filter_functions_vsx(png_structp pp, unsigned int bpp)
+{
+   /* The switch statement is compiled in for POWERPC_VSX_API, the call to
+    * png_have_vsx is compiled in for POWERPC_VSX_CHECK. If both are defined
+    * the check is only performed if the API has not set the PowerPC option on
+    * or off explicitly. In this case the check controls what happens.
+    */
+
+#ifdef PNG_POWERPC_VSX_API_SUPPORTED
+   switch ((pp->options >> PNG_POWERPC_VSX) & 3)
+   {
+      case PNG_OPTION_UNSET:
+         /* Allow the run-time check to execute if it has been enabled -
+          * thus both API and CHECK can be turned on.  If it isn't supported
+          * this case will fall through to the 'default' below, which just
+          * returns.
+          */
+#endif /* PNG_POWERPC_VSX_API_SUPPORTED */
+#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
+         {
+            static volatile sig_atomic_t no_vsx = -1; /* not checked */
+
+            if (no_vsx < 0)
+               no_vsx = !png_have_vsx(pp);
+
+            if (no_vsx)
+               return;
+         }
+#ifdef PNG_POWERPC_VSX_API_SUPPORTED
+         break;
+#endif
+#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
+
+#ifdef PNG_POWERPC_VSX_API_SUPPORTED
+      default: /* OFF or INVALID */
+         return;
+
+      case PNG_OPTION_ON:
+         /* Option turned on */
+         break;
+   }
+#endif
+
+   /* IMPORTANT: any new internal functions used here must be declared using
+    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
+    * 'prefix' option to configure works:
+    *
+    *    ./configure --with-libpng-prefix=foobar_
+    *
+    * Verify you have got this right by running the above command, doing a build
+    * and examining pngprefix.h; it must contain a #define for every external
+    * function you add.  (Notice that this happens automatically for the
+    * initialization function.)
+    */
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_vsx;
+
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_vsx;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_vsx;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_vsx;
+   }
+
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_vsx;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_vsx;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_vsx;
+   }
+}
+#endif /* PNG_POWERPC_VSX_OPT > 0 */
+#endif /* READ */
diff --git a/extern/libpng/projects/owatcom/libpng.tgt b/extern/libpng/projects/owatcom/libpng.tgt
new file mode 100644
index 0000000000..4a9622e68c
--- /dev/null
+++ b/extern/libpng/projects/owatcom/libpng.tgt
@@ -0,0 +1,383 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+3
+LIB
+3
+WString
+5
+n_2sn
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+0
+6
+MItem
+10
+libpng.lib
+7
+WString
+3
+LIB
+8
+WVList
+0
+9
+WVList
+1
+10
+ActionStates
+11
+WString
+5
+&Make
+12
+WVList
+0
+-1
+1
+1
+0
+13
+WPickList
+16
+14
+MItem
+3
+*.c
+15
+WString
+4
+COBJ
+16
+WVList
+2
+17
+MVState
+18
+WString
+3
+WCC
+19
+WString
+25
+n????Include directories:
+1
+20
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+21
+MVState
+22
+WString
+3
+WCC
+23
+WString
+25
+n????Include directories:
+0
+24
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+25
+WVList
+1
+26
+ActionStates
+27
+WString
+5
+&Make
+28
+WVList
+0
+-1
+1
+1
+0
+29
+MItem
+11
+..\..\png.c
+30
+WString
+4
+COBJ
+31
+WVList
+0
+32
+WVList
+0
+14
+1
+1
+0
+33
+MItem
+16
+..\..\pngerror.c
+34
+WString
+4
+COBJ
+35
+WVList
+0
+36
+WVList
+0
+14
+1
+1
+0
+37
+MItem
+14
+..\..\pngget.c
+38
+WString
+4
+COBJ
+39
+WVList
+0
+40
+WVList
+0
+14
+1
+1
+0
+41
+MItem
+14
+..\..\pngmem.c
+42
+WString
+4
+COBJ
+43
+WVList
+0
+44
+WVList
+0
+14
+1
+1
+0
+45
+MItem
+16
+..\..\pngpread.c
+46
+WString
+4
+COBJ
+47
+WVList
+0
+48
+WVList
+0
+14
+1
+1
+0
+49
+MItem
+15
+..\..\pngread.c
+50
+WString
+4
+COBJ
+51
+WVList
+0
+52
+WVList
+0
+14
+1
+1
+0
+53
+MItem
+14
+..\..\pngrio.c
+54
+WString
+4
+COBJ
+55
+WVList
+0
+56
+WVList
+0
+14
+1
+1
+0
+57
+MItem
+16
+..\..\pngrtran.c
+58
+WString
+4
+COBJ
+59
+WVList
+0
+60
+WVList
+0
+14
+1
+1
+0
+61
+MItem
+16
+..\..\pngrutil.c
+62
+WString
+4
+COBJ
+63
+WVList
+0
+64
+WVList
+0
+14
+1
+1
+0
+65
+MItem
+14
+..\..\pngset.c
+66
+WString
+4
+COBJ
+67
+WVList
+0
+68
+WVList
+0
+14
+1
+1
+0
+69
+MItem
+16
+..\..\pngtrans.c
+70
+WString
+4
+COBJ
+71
+WVList
+0
+72
+WVList
+0
+14
+1
+1
+0
+73
+MItem
+14
+..\..\pngwio.c
+74
+WString
+4
+COBJ
+75
+WVList
+0
+76
+WVList
+0
+14
+1
+1
+0
+77
+MItem
+16
+..\..\pngwrite.c
+78
+WString
+4
+COBJ
+79
+WVList
+0
+80
+WVList
+0
+14
+1
+1
+0
+81
+MItem
+16
+..\..\pngwtran.c
+82
+WString
+4
+COBJ
+83
+WVList
+0
+84
+WVList
+0
+14
+1
+1
+0
+85
+MItem
+16
+..\..\pngwutil.c
+86
+WString
+4
+COBJ
+87
+WVList
+0
+88
+WVList
+0
+14
+1
+1
+0
diff --git a/extern/libpng/projects/owatcom/libpng.wpj b/extern/libpng/projects/owatcom/libpng.wpj
new file mode 100644
index 0000000000..a70d95f96b
--- /dev/null
+++ b/extern/libpng/projects/owatcom/libpng.wpj
@@ -0,0 +1,112 @@
+40
+projectIdent
+0
+VpeMain
+1
+WRect
+256
+0
+8960
+9294
+2
+MProject
+3
+MCommand
+322
+# Locations of zlib and (if required) awk (change as required:)
+set zlib=..\..\..\zlib
+set awk=
+#
+@if not exist pngconfig.dfa $(MAKE) $(__MAKEOPTS__) -f pngconfig.mak defaults
+@if exist config.inf type config.inf
+@echo Checking for the libpng configuration file pnglibconf.h
+$(MAKE) $(__MAKEOPTS__) -f pngconfig.mak
+4
+MCommand
+19
+@type pngconfig.inf
+4
+5
+WFileName
+10
+libpng.tgt
+6
+WFileName
+11
+pngtest.tgt
+7
+WFileName
+12
+pngvalid.tgt
+8
+WFileName
+12
+pngstest.tgt
+9
+WVList
+4
+10
+VComponent
+11
+WRect
+0
+0
+5638
+4174
+0
+0
+12
+WFileName
+10
+libpng.tgt
+0
+0
+13
+VComponent
+14
+WRect
+1280
+1550
+5638
+4174
+0
+0
+15
+WFileName
+11
+pngtest.tgt
+0
+1
+16
+VComponent
+17
+WRect
+524
+497
+5638
+4174
+0
+0
+18
+WFileName
+12
+pngvalid.tgt
+0
+1
+19
+VComponent
+20
+WRect
+2054
+2701
+5674
+4232
+0
+0
+21
+WFileName
+12
+pngstest.tgt
+0
+1
+19
diff --git a/extern/libpng/projects/owatcom/pngconfig.mak b/extern/libpng/projects/owatcom/pngconfig.mak
new file mode 100644
index 0000000000..11f1aa72bc
--- /dev/null
+++ b/extern/libpng/projects/owatcom/pngconfig.mak
@@ -0,0 +1,160 @@
+# This is an OpenWatcom make file which builds pnglibconf.h - the libpng
+# configuration header.  You can ignore this file if you don't need to
+# configure libpng; a default configuration will be built.
+#
+# For more information build libpng.wpj under the IDE and then read the
+# generated files:
+#
+#    config.inf: Basic configuration information for a standard build.
+#    pngconfig.dfa: Advanced configuration for non-standard libpng builds.
+#
+DELETE=rm -f
+ECHO=echo
+COPY=copy
+#
+# If your configuration needs to test compiler flags when building
+# pnglibconf.h you may need to override the following on the wmake command
+# line:
+CFLAGS=
+CC=wcl386
+CPP=$(CC) -pw0
+#
+# Read awk from the environment if set, else it can be set on the command
+# line (the default approach is to set the %awk% environment variable in the
+# IDE libpng.wpj 'before' rule - this setting is local.)
+!ifdef %awk
+AWK=$(%awk)
+!endif
+#
+# pnglibconf.h must exist in the source directory, this is the final rule
+# which copies the local built version (and this is the default target for
+# this makefile.)
+..\..\pnglibconf.h: pnglibconf.h
+ $(COPY) pnglibconf.h $@
+
+!ifdef AWK
+# CPPFLAGS should contain the options to control the result,
+# but DEFS and CFLAGS are also supported here, override
+# as appropriate
+DFNFLAGS = $(DEFS) $(CPPFLAGS) $(CFLAGS)
+
+pnglibconf.h: pnglibconf.dfn
+ $(DELETE) $@ dfn.c dfn1.out dfn2.out
+ $(ECHO) $#include "pnglibconf.dfn" >dfn.c
+ $(CPP) $(DFNFLAGS) dfn.c >dfn1.out
+ $(AWK) -f << dfn1.out >dfn2.out
+/^.*PNG_DEFN_MAGIC-.*-PNG_DEFN_END.*$$/{
+ sub(/^.*PNG_DEFN_MAGIC-/, "")
+ sub(/ *-PNG_DEFN_END.*$$/, "")
+ gsub(/ *@@@ */, "")
+ print
+}
+<<
+ $(COPY) dfn2.out $@
+ @type << >pngconfig.inf
+This is a locally configurable build of libpng.lib; for configuration
+instructions consult and edit projects/openwatcom/pngconfig.dfa
+<<
+ $(DELETE) dfn.c dfn1.out dfn2.out
+
+pnglibconf.dfn: ..\..\scripts\pnglibconf.dfa ..\..\scripts\options.awk pngconfig.dfa ..\..\pngconf.h
+ $(DELETE) $@ dfn1.out dfn2.out
+ $(AWK) -f ..\..\scripts\options.awk out=dfn1.out version=search ..\..\pngconf.h ..\..\scripts\pnglibconf.dfa pngconfig.dfa $(DFA_XTRA) 1>&2
+ $(AWK) -f ..\..\scripts\options.awk out=dfn2.out dfn1.out 1>&2
+ $(COPY) dfn2.out $@
+ $(DELETE) dfn1.out dfn2.out
+
+!else
+# The following lines are used to copy scripts\pnglibconf.h.prebuilt and make
+# the required change to the calling convention.
+#
+# By default libpng is built to use the __cdecl calling convention on
+# Windows.  This gives compatibility with MSVC and GCC.  Unfortunately it
+# does not work with OpenWatcom because OpenWatcom implements longjmp using
+# the __watcall convention (compared with both MSVC and GCC which use __cdecl
+# for library functions.)
+#
+# Thus the default must be changed to build on OpenWatcom and, once changed,
+# the result will not be compatible with applications built using other
+# compilers (in fact attempts to build will fail at compile time.)
+#
+pnglibconf.h: ..\..\scripts\pnglibconf.h.prebuilt .existsonly
+ @$(ECHO) .
+ @$(ECHO) .
+ @$(ECHO) $$(AWK) NOT AVAILABLE: COPYING scripts\pnglibconf.h.prebuilt
+ @$(ECHO) .
+ @$(ECHO) .
+ vi -q -k ":1,$$s/PNG_API_RULE 0$$/PNG_API_RULE 2/\n:w! $@\n:q!\n" ..\..\scripts\pnglibconf.h.prebuilt
+ @$(ECHO) .
+ @$(ECHO) .
+ @$(ECHO) YOU HAVE A DEFAULT CONFIGURATION BECAUSE YOU DO NOT HAVE AWK!
+ @$(ECHO) .
+ @$(ECHO) .
+ @type << >pngconfig.inf
+This is the default configuration of libpng.lib, if you wish to
+change the configuration please consult the instructions in
+projects/owatcom/pngconfig.dfa.
+<<
+
+!endif
+
+# Make the default files
+defaults: .symbolic
+ @$(COPY) << config.inf
+$# The libpng project is incompletely configured.  To complete configuration
+$# please complete the following steps:
+$#
+$#   1) Edit the 'before' rule of libpng.wpj (from the IDE) to define the
+$#      locations of the zlib include file zlib.h and the built zlib library,
+$#      zlib.lib.
+$#
+$#   2) If you want to change libpng to a non-standard configuration also
+$#      change the definition of 'awk' in the before rule to the name of your
+$#      awk command.  For more instructions on configuration read
+$#      pngconfig.dfa.
+$#
+$#   3) Delete this file (config.inf).
+<<
+ @$(COPY) << pngconfig.dfa
+$# pngconfig.dfa: this file contains configuration options for libpng.
+$# If empty the standard configuration will be built.  For this file to be
+$# used a working version of the program 'awk' is required and the program
+$# must be identified in the 'before' rule of the project.
+$#
+$# If you don't already have 'awk', or the version of awk you have seems not
+$# to work, download Brian Kernighan's awk (Brian Kernighan is the author of
+$# awk.)  You can find source code and a built executable (called awk95.exe)
+$# here:
+$#
+$#     https://www.cs.princeton.edu/~bwk/btl.mirror/
+$#
+$# The executable works just fine.
+$#
+$# If build issues errors after a change to pngconfig.dfa you have entered
+$# inconsistent feature requests, or even malformed requests, in
+$# pngconfig.dfa.  The error messages from awk should be comprehensible, but
+$# if not simply go back to the start (nothing but comments in this file) and
+$# enter configuration lines one by one until one produces an error.  (Or, of
+$# course, do the standard binary chop.)
+$#
+$# You need to rebuild everything after a change to pnglibconf.dfa - i.e. you
+$# must do Actions/Mark All Targets for Remake.  This is because the compiler
+$# generated dependency information (as of OpenWatcom 1.9) does not record the
+$# dependency on pnglibconf.h correctly.
+$#
+$# If awk isn't set then this file is bypassed.  If you just want the standard
+$# configuration it is automatically produced from the distributed version
+$# (scripts\pnglibconf.h.prebuilt) by editing PNG_API_RULE to 2 (to force use
+$# of the OpenWatcom library calling convention.)
+$#
+<<
+
+clean:: .symbolic
+ $(DELETE) ..\..\pnglibconf.h pnglibconf.* dfn.c *.out pngconfig.inf
+ $(DELETE) *.obj *.mbr *.sym *.err *.pch libpng.mk
+ $(DELETE) libpng.lib libpng.lbr libpng.lb1 libpng.cbr libpng.mk1
+ $(DELETE) pngtest.exe pngtest.map pngtest.lk1 pngtest.mk1
+ $(DELETE) pngvalid.exe pngvalid.map pngvalid.lk1 pngvalid.mk1
+
+distclean:: clean .symbolic
+ $(DELETE) zlib.inf awk.inf config.inf pngconfig.dfa
diff --git a/extern/libpng/projects/owatcom/pngstest.tgt b/extern/libpng/projects/owatcom/pngstest.tgt
new file mode 100644
index 0000000000..f5d024518f
--- /dev/null
+++ b/extern/libpng/projects/owatcom/pngstest.tgt
@@ -0,0 +1,219 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+4
+NEXE
+3
+WString
+5
+nc2en
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+1118
+pngstest --strict --log ../../contrib/pngsuite/basn0g01.png ../../contrib/pngsuite/basn0g02.png ../../contrib/pngsuite/basn0g04.png ../../contrib/pngsuite/basn0g08.png ../../contrib/pngsuite/basn0g16.png ../../contrib/pngsuite/basn2c08.png ../../contrib/pngsuite/basn2c16.png ../../contrib/pngsuite/basn3p01.png ../../contrib/pngsuite/basn3p02.png ../../contrib/pngsuite/basn3p04.png ../../contrib/pngsuite/basn3p08.png ../../contrib/pngsuite/basn4a08.png ../../contrib/pngsuite/basn4a16.png ../../contrib/pngsuite/basn6a08.png ../../contrib/pngsuite/basn6a16.png ../../contrib/pngsuite/ftbbn0g04.png ../../contrib/pngsuite/ftbbn0g01.png ../../contrib/pngsuite/ftbbn0g02.png ../../contrib/pngsuite/ftbbn2c16.png ../../contrib/pngsuite/ftbbn3p08.png ../../contrib/pngsuite/ftbgn2c16.png ../../contrib/pngsuite/ftbgn3p08.png ../../contrib/pngsuite/ftbrn2c08.png ../../contrib/pngsuite/ftbwn0g16.png ../../contrib/pngsuite/ftbwn3p08.png ../../contrib/pngsuite/ftbyn3p08.png ../../contrib/pngsuite/ftp0n0g08.png ../../contrib/pngsuite/ftp0n2c08.png ../../contrib/pngsuite/ftp0n3p08.png ../../contrib/pngsuite/ftp1n3p08.png
+6
+MItem
+12
+pngstest.exe
+7
+WString
+4
+NEXE
+8
+WVList
+6
+9
+MVState
+10
+WString
+7
+WINLINK
+11
+WString
+11
+?????Stack:
+1
+12
+WString
+4
+768k
+0
+13
+MVState
+14
+WString
+7
+WINLINK
+15
+WString
+28
+?????Library directories(;):
+1
+16
+WString
+8
+$(%zlib)
+0
+17
+MVState
+18
+WString
+7
+WINLINK
+19
+WString
+18
+?????Libraries(,):
+1
+20
+WString
+19
+libpng.lib zlib.lib
+0
+21
+MVState
+22
+WString
+7
+WINLINK
+23
+WString
+11
+?????Stack:
+0
+24
+WString
+4
+768k
+0
+25
+MVState
+26
+WString
+7
+WINLINK
+27
+WString
+28
+?????Library directories(;):
+0
+28
+WString
+8
+$(%zlib)
+0
+29
+MVState
+30
+WString
+7
+WINLINK
+31
+WString
+18
+?????Libraries(,):
+0
+32
+WString
+19
+libpng.lib zlib.lib
+0
+33
+WVList
+1
+34
+ActionStates
+35
+WString
+4
+&Run
+36
+WVList
+0
+-1
+1
+1
+0
+37
+WPickList
+2
+38
+MItem
+3
+*.c
+39
+WString
+4
+COBJ
+40
+WVList
+2
+41
+MVState
+42
+WString
+3
+WCC
+43
+WString
+25
+n????Include directories:
+1
+44
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+45
+MVState
+46
+WString
+3
+WCC
+47
+WString
+25
+n????Include directories:
+0
+48
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+49
+WVList
+0
+-1
+1
+1
+0
+50
+MItem
+33
+..\..\contrib\libtests\pngstest.c
+51
+WString
+4
+COBJ
+52
+WVList
+0
+53
+WVList
+0
+38
+1
+1
+0
diff --git a/extern/libpng/projects/owatcom/pngtest.tgt b/extern/libpng/projects/owatcom/pngtest.tgt
new file mode 100644
index 0000000000..211f1a7488
--- /dev/null
+++ b/extern/libpng/projects/owatcom/pngtest.tgt
@@ -0,0 +1,179 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+4
+NEXE
+3
+WString
+5
+nc2en
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+34
+cd ..\..
+projects\owatcom\pngtest
+6
+MItem
+11
+pngtest.exe
+7
+WString
+4
+NEXE
+8
+WVList
+4
+9
+MVState
+10
+WString
+7
+WINLINK
+11
+WString
+28
+?????Library directories(;):
+1
+12
+WString
+8
+$(%zlib)
+0
+13
+MVState
+14
+WString
+7
+WINLINK
+15
+WString
+18
+?????Libraries(,):
+1
+16
+WString
+19
+libpng.lib zlib.lib
+0
+17
+MVState
+18
+WString
+7
+WINLINK
+19
+WString
+28
+?????Library directories(;):
+0
+20
+WString
+8
+$(%zlib)
+0
+21
+MVState
+22
+WString
+7
+WINLINK
+23
+WString
+18
+?????Libraries(,):
+0
+24
+WString
+19
+libpng.lib zlib.lib
+0
+25
+WVList
+0
+-1
+1
+1
+0
+26
+WPickList
+2
+27
+MItem
+3
+*.c
+28
+WString
+4
+COBJ
+29
+WVList
+2
+30
+MVState
+31
+WString
+3
+WCC
+32
+WString
+25
+n????Include directories:
+1
+33
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+34
+MVState
+35
+WString
+3
+WCC
+36
+WString
+25
+n????Include directories:
+0
+37
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+38
+WVList
+0
+-1
+1
+1
+0
+39
+MItem
+15
+..\..\pngtest.c
+40
+WString
+4
+COBJ
+41
+WVList
+0
+42
+WVList
+0
+27
+1
+1
+0
diff --git a/extern/libpng/projects/owatcom/pngvalid.tgt b/extern/libpng/projects/owatcom/pngvalid.tgt
new file mode 100644
index 0000000000..1e78e75cb6
--- /dev/null
+++ b/extern/libpng/projects/owatcom/pngvalid.tgt
@@ -0,0 +1,210 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+4
+NEXE
+3
+WString
+5
+nc2en
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+8
+pngvalid
+6
+MItem
+12
+pngvalid.exe
+7
+WString
+4
+NEXE
+8
+WVList
+6
+9
+MVState
+10
+WString
+7
+WINLINK
+11
+WString
+11
+?????Stack:
+1
+12
+WString
+4
+768k
+0
+13
+MVState
+14
+WString
+7
+WINLINK
+15
+WString
+28
+?????Library directories(;):
+1
+16
+WString
+8
+$(%zlib)
+0
+17
+MVState
+18
+WString
+7
+WINLINK
+19
+WString
+18
+?????Libraries(,):
+1
+20
+WString
+19
+libpng.lib zlib.lib
+0
+21
+MVState
+22
+WString
+7
+WINLINK
+23
+WString
+11
+?????Stack:
+0
+24
+WString
+4
+768k
+0
+25
+MVState
+26
+WString
+7
+WINLINK
+27
+WString
+28
+?????Library directories(;):
+0
+28
+WString
+8
+$(%zlib)
+0
+29
+MVState
+30
+WString
+7
+WINLINK
+31
+WString
+18
+?????Libraries(,):
+0
+32
+WString
+19
+libpng.lib zlib.lib
+0
+33
+WVList
+0
+-1
+1
+1
+0
+34
+WPickList
+2
+35
+MItem
+3
+*.c
+36
+WString
+4
+COBJ
+37
+WVList
+2
+38
+MVState
+39
+WString
+3
+WCC
+40
+WString
+25
+n????Include directories:
+1
+41
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+42
+MVState
+43
+WString
+3
+WCC
+44
+WString
+25
+n????Include directories:
+0
+45
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+46
+WVList
+0
+-1
+1
+1
+0
+47
+MItem
+33
+..\..\contrib\libtests\pngvalid.c
+48
+WString
+4
+COBJ
+49
+WVList
+0
+50
+WVList
+0
+35
+1
+1
+0
diff --git a/extern/libpng/projects/visualc71/PRJ0041.mak b/extern/libpng/projects/visualc71/PRJ0041.mak
new file mode 100644
index 0000000000..c7a68b503e
--- /dev/null
+++ b/extern/libpng/projects/visualc71/PRJ0041.mak
@@ -0,0 +1,21 @@
+# Prevent "Cannot find missing dependency..." warnings while compiling
+# pngwin.rc (PRJ0041).
+
+all: $(IntDir)\alloc.h \
+	 $(IntDir)\fp.h \
+	 $(IntDir)\m68881.h \
+	 $(IntDir)\mem.h \
+	 $(IntDir)\pngusr.h \
+	 $(IntDir)\strings.h \
+	 $(IntDir)\unistd.h \
+	 $(IntDir)\unixio.h
+
+$(IntDir)\alloc.h \
+$(IntDir)\fp.h \
+$(IntDir)\m68881.h \
+$(IntDir)\mem.h \
+$(IntDir)\pngusr.h \
+$(IntDir)\strings.h \
+$(IntDir)\unistd.h \
+$(IntDir)\unixio.h:
+	@!echo.>$@
diff --git a/extern/libpng/projects/visualc71/README.txt b/extern/libpng/projects/visualc71/README.txt
new file mode 100644
index 0000000000..4e1c8fa1c5
--- /dev/null
+++ b/extern/libpng/projects/visualc71/README.txt
@@ -0,0 +1,58 @@
+Microsoft Developer Studio Project File, Format Version 7.10 for libpng.
+
+Copyright (C) 2004 Simon-Pierre Cadieux.
+
+This code is released under the libpng license.
+For conditions of distribution and use, see copyright notice in png.h
+
+NOTE: This project will be removed from libpng-1.5.0.  It has
+been replaced with the "vstudio" project.
+
+Assumptions:
+* The libpng source files are in ..\..
+* The zlib source files are in ..\..\..\zlib
+* The zlib project file is in . /* Warning: This is until the zlib project
+  files get integrated into the next zlib release. The final zlib project
+  directory will then be ..\..\..\zlib\projects\visualc71. */
+
+To use:
+
+1) On the main menu, select "File | Open Solution".
+   Open "libpng.sln".
+
+2) Display the Solution Explorer view (Ctrl+Alt+L)
+
+3) Set one of the project as the StartUp project. If you just want to build the
+   binaries set "libpng" as the startup project (Select "libpng" tree view
+   item + Project | Set as StartUp project). If you want to build and test the
+   binaries set it to "pngtest" (Select "pngtest" tree view item +
+   Project | Set as StartUp project)
+
+4) Select "Build | Configuration Manager...".
+   Choose the configuration you wish to build.
+
+5) Select "Build | Clean Solution".
+
+6) Select "Build | Build Solution (Ctrl-Shift-B)"
+
+This project builds the libpng binaries as follows:
+
+* Win32_DLL_Release\libpng16.dll      DLL build
+* Win32_DLL_Debug\libpng16d.dll       DLL build (debug version)
+* Win32_DLL_VB\libpng16vb.dll         DLL build for Visual Basic, using stdcall
+* Win32_LIB_Release\libpng.lib        static build
+* Win32_LIB_Debug\libpngd.lib         static build (debug version)
+
+Notes:
+
+If you change anything in the source files, or select different compiler
+settings, please change the DLL name to something different than any of
+the above names. Also, make sure that in your "pngusr.h" you define
+PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX according to the
+instructions provided in "pngconf.h".
+
+All DLLs built by this project use the Microsoft dynamic C runtime library
+MSVCR71.DLL (MSVCR71D.DLL for debug versions).  If you distribute any of the
+above mentioned libraries you may have to include this DLL in your package.
+For a list of files that are redistributable in Visual Studio see
+$(VCINSTALLDIR)\redist.txt.
diff --git a/extern/libpng/projects/visualc71/README_zlib.txt b/extern/libpng/projects/visualc71/README_zlib.txt
new file mode 100644
index 0000000000..81d11cbb57
--- /dev/null
+++ b/extern/libpng/projects/visualc71/README_zlib.txt
@@ -0,0 +1,44 @@
+/* WARNING: This file was put in the LibPNG distribution for convenience only.
+            It is expected to be part of the next zlib release under
+            "projects\visualc71\README.txt." */
+
+Microsoft Developer Studio Project File, Format Version 7.10 for zlib.
+
+Copyright (C) 2004 Simon-Pierre Cadieux.
+Copyright (C) 2004 Cosmin Truta.
+
+This code is released under the libpng license.
+For conditions of distribution and use, see copyright notice in zlib.h.
+
+NOTE: This project will be removed from libpng-1.5.0.  It has
+been replaced with the "vstudio" project.
+
+To use:
+
+1) On the main menu, select "File | Open Solution".
+   Open "zlib.sln".
+
+2) Display the Solution Explorer view (Ctrl+Alt+L)
+
+3) Set one of the project as the StartUp project. If you just want to build the
+   binaries set "zlib" as the startup project (Select "zlib" tree view item +
+   Project | Set as StartUp project). If you want to build and test the
+   binaries set it to "example" (Select "example" tree view item + Project |
+   Set as StartUp project), If you want to build the minigzip utility set it to
+   "minigzip" (Select "minigzip" tree view item + Project | Set as StartUp
+   project
+
+4) Select "Build | Configuration Manager...".
+   Choose the configuration you wish to build.
+
+5) Select "Build | Clean Solution".
+
+6) Select "Build | Build Solution (Ctrl-Shift-B)"
+
+This project builds the zlib binaries as follows:
+
+* Win32_DLL_Release\zlib1.dll       DLL build
+* Win32_DLL_Debug\zlib1d.dll        DLL build (debug version)
+* Win32_LIB_Release\zlib.lib        static build
+* Win32_LIB_Debug\zlibd.lib         static build (debug version)
+
diff --git a/extern/libpng/projects/visualc71/libpng.sln b/extern/libpng/projects/visualc71/libpng.sln
new file mode 100644
index 0000000000..eeb101f2e3
--- /dev/null
+++ b/extern/libpng/projects/visualc71/libpng.sln
@@ -0,0 +1,60 @@
+Microsoft Visual Studio Solution File, Format Version 8.00
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "libpng", "libpng.vcproj", "{0008960E-E0DD-41A6-8265-00B31DDB4C21}"
+	ProjectSection(ProjectDependencies) = postProject
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0} = {2D4F8105-7D21-454C-9932-B47CAB71A5C0}
+	EndProjectSection
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngtest", "pngtest.vcproj", "{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}"
+	ProjectSection(ProjectDependencies) = postProject
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21} = {0008960E-E0DD-41A6-8265-00B31DDB4C21}
+	EndProjectSection
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "zlib", "zlib.vcproj", "{2D4F8105-7D21-454C-9932-B47CAB71A5C0}"
+	ProjectSection(ProjectDependencies) = postProject
+	EndProjectSection
+EndProject
+Global
+	GlobalSection(SolutionConfiguration) = preSolution
+		DLL Debug = DLL Debug
+		DLL Release = DLL Release
+		DLL VB = DLL VB
+		LIB Debug = LIB Debug
+		LIB Release = LIB Release
+	EndGlobalSection
+	GlobalSection(ProjectConfiguration) = postSolution
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Debug.ActiveCfg = DLL Debug|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Debug.Build.0 = DLL Debug|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Release.ActiveCfg = DLL Release|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Release.Build.0 = DLL Release|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL VB.ActiveCfg = DLL VB|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL VB.Build.0 = DLL VB|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Debug.ActiveCfg = LIB Debug|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Debug.Build.0 = LIB Debug|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Release.ActiveCfg = LIB Release|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Release.Build.0 = LIB Release|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Debug.ActiveCfg = DLL Debug|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Debug.Build.0 = DLL Debug|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Release.ActiveCfg = DLL Release|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Release.Build.0 = DLL Release|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL VB.ActiveCfg = DLL VB|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL VB.Build.0 = DLL VB|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Debug.ActiveCfg = LIB Debug|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Debug.Build.0 = LIB Debug|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Release.ActiveCfg = LIB Release|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Release.Build.0 = LIB Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Debug.ActiveCfg = DLL Debug|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Debug.Build.0 = DLL Debug|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Release.ActiveCfg = DLL Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Release.Build.0 = DLL Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL VB.ActiveCfg = DLL Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL VB.Build.0 = DLL Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Debug.ActiveCfg = LIB Debug|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Debug.Build.0 = LIB Debug|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Release.ActiveCfg = LIB Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Release.Build.0 = LIB Release|Win32
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+	EndGlobalSection
+	GlobalSection(ExtensibilityAddIns) = postSolution
+	EndGlobalSection
+EndGlobal
diff --git a/extern/libpng/projects/visualc71/libpng.vcproj b/extern/libpng/projects/visualc71/libpng.vcproj
new file mode 100644
index 0000000000..608ec4e6b4
--- /dev/null
+++ b/extern/libpng/projects/visualc71/libpng.vcproj
@@ -0,0 +1,419 @@
+<?xml version="1.0" encoding="Windows-1252"?>
+<VisualStudioProject
+	ProjectType="Visual C++"
+	Version="7.10"
+	Name="libpng"
+	RootNamespace="libpng">
+	<Platforms>
+		<Platform
+			Name="Win32"/>
+	</Platforms>
+	<Configurations>
+		<Configuration
+			Name="DLL Release|Win32"
+			OutputDirectory=".\Win32_DLL_Release"
+			IntermediateDirectory=".\Win32_DLL_Release"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;PNG_BUILD_DLL;ZLIB_DLL;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/libpng16.dll"
+				LinkIncremental="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="NDEBUG"
+				Culture="1033"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL Debug|Win32"
+			OutputDirectory=".\Win32_DLL_Debug"
+			IntermediateDirectory=".\Win32_DLL_Debug"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;PNG_DEBUG=1;PNG_BUILD_DLL;ZLIB_DLL;_CRT_SECURE_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="3"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/libpng16d.dll"
+				GenerateDebugInformation="TRUE"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="_DEBUG,PNG_DEBUG=1"
+				Culture="1033"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL VB|Win32"
+			OutputDirectory=".\Win32_DLL_VB"
+			IntermediateDirectory=".\Win32_DLL_VB"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;PNG_BUILD_DLL;ZLIB_DLL;PNGAPI=__stdcall;PNG_NO_MODULEDEF;PNG_LIBPNG_SPECIALBUILD;PNG_USER_PRIVATEBUILD;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/libpng16vb.dll"
+				LinkIncremental="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				AdditionalOptions="/d PNG_NO_PEDANTIC_WARNINGS /d PNG_LIBPNG_DLLFNAME_POSTFIX=&quot;&quot;&quot;&quot;VB&quot;&quot;&quot;&quot; /d PNG_LIBPNG_SPECIALBUILD=&quot;&quot;&quot;&quot;__stdcall calling convention used for exported functions&quot;&quot;&quot;&quot;"
+				PreprocessorDefinitions="NDEBUG"
+				Culture="1033"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Release|Win32"
+			OutputDirectory=".\Win32_LIB_Release"
+			IntermediateDirectory=".\Win32_LIB_Release"
+			ConfigurationType="4">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="0"
+				EnableFunctionLevelLinking="TRUE"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLibrarianTool"
+				OutputFile="$(OutDir)/libpng.lib"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Debug|Win32"
+			OutputDirectory=".\Win32_LIB_Debug"
+			IntermediateDirectory=".\Win32_LIB_Debug"
+			ConfigurationType="4">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;PNG_DEBUG=1;_CRT_SECURE_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="1"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLibrarianTool"
+				OutputFile="$(OutDir)/libpngd.lib"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+	</Configurations>
+	<References>
+	</References>
+	<Files>
+		<Filter
+			Name="Source Files"
+			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
+			<File
+				RelativePath="..\..\png.c">
+				<FileConfiguration
+					Name="DLL Release|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL VB|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\pngerror.c">
+				<FileConfiguration
+					Name="DLL Release|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL VB|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\pngget.c">
+			</File>
+			<File
+				RelativePath="..\..\pngmem.c">
+			</File>
+			<File
+				RelativePath="..\..\pngpread.c">
+			</File>
+			<File
+				RelativePath="..\..\pngread.c">
+			</File>
+			<File
+				RelativePath="..\..\pngrio.c">
+			</File>
+			<File
+				RelativePath="..\..\pngrtran.c">
+			</File>
+			<File
+				RelativePath="..\..\pngrutil.c">
+			</File>
+			<File
+				RelativePath="..\..\pngset.c">
+			</File>
+			<File
+				RelativePath="..\..\pngtrans.c">
+			</File>
+			<File
+				RelativePath="..\..\pngwio.c">
+			</File>
+			<File
+				RelativePath="..\..\pngwrite.c">
+			</File>
+			<File
+				RelativePath="..\..\pngwtran.c">
+			</File>
+			<File
+				RelativePath="..\..\pngwutil.c">
+			</File>
+		</Filter>
+		<Filter
+			Name="Header Files"
+			Filter="h;hpp;hxx;hm;inl">
+			<File
+				RelativePath="..\..\png.h">
+			</File>
+			<File
+				RelativePath="..\..\pngconf.h">
+			</File>
+			<File
+				RelativePath="..\..\pngpriv.h">
+			</File>
+		</Filter>
+		<Filter
+			Name="Resource Files"
+			Filter="ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe">
+			<File
+				RelativePath="..\..\scripts\pngwin.rc">
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCResourceCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCResourceCompilerTool"/>
+				</FileConfiguration>
+			</File>
+		</Filter>
+		<File
+			RelativePath=".\PRJ0041.mak">
+			<FileConfiguration
+				Name="DLL Release|Win32">
+				<Tool
+					Name="VCCustomBuildTool"
+					Description="Create dummy include files to prevent &quot;Cannot find missing dependency...&quot; warnings."
+					CommandLine="nmake -f PRJ0041.mak IntDir=$(IntDir)"
+					Outputs="$(IntDir)\alloc.h;$(IntDir)\fp.h;$(IntDir)\m68881.h;$(IntDir)\mem.h;$(IntDir)\pngusr.h;$(IntDir)\strings.h;$(IntDir)\unistd.h;$(IntDir)\unixio.h"/>
+			</FileConfiguration>
+			<FileConfiguration
+				Name="DLL Debug|Win32">
+				<Tool
+					Name="VCCustomBuildTool"
+					Description="Create dummy include files to prevent &quot;Cannot find missing dependency...&quot; warnings."
+					CommandLine="nmake -f PRJ0041.mak IntDir=$(IntDir)"
+					Outputs="$(IntDir)\alloc.h;$(IntDir)\fp.h;$(IntDir)\m68881.h;$(IntDir)\mem.h;$(IntDir)\pngusr.h;$(IntDir)\strings.h;$(IntDir)\unistd.h;$(IntDir)\unixio.h"/>
+			</FileConfiguration>
+			<FileConfiguration
+				Name="DLL VB|Win32">
+				<Tool
+					Name="VCCustomBuildTool"
+					Description="Create dummy include files to prevent &quot;Cannot find missing dependency...&quot; warnings."
+					CommandLine="nmake -f PRJ0041.mak IntDir=$(IntDir)"
+					Outputs="$(IntDir)\alloc.h;$(IntDir)\fp.h;$(IntDir)\m68881.h;$(IntDir)\mem.h;$(IntDir)\pngusr.h;$(IntDir)\strings.h;$(IntDir)\unistd.h;$(IntDir)\unixio.h"/>
+			</FileConfiguration>
+		</File>
+		<File
+			RelativePath="README.txt">
+		</File>
+	</Files>
+	<Globals>
+	</Globals>
+</VisualStudioProject>
diff --git a/extern/libpng/projects/visualc71/pngtest.vcproj b/extern/libpng/projects/visualc71/pngtest.vcproj
new file mode 100644
index 0000000000..3b48f1cf6f
--- /dev/null
+++ b/extern/libpng/projects/visualc71/pngtest.vcproj
@@ -0,0 +1,267 @@
+<?xml version="1.0" encoding="Windows-1252"?>
+<VisualStudioProject
+	ProjectType="Visual C++"
+	Version="7.10"
+	Name="pngtest"
+	RootNamespace="pngtest">
+	<Platforms>
+		<Platform
+			Name="Win32"/>
+	</Platforms>
+	<Configurations>
+		<Configuration
+			Name="DLL Release|Win32"
+			OutputDirectory=".\Win32_DLL_Release\Test"
+			IntermediateDirectory=".\Win32_DLL_Release\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;PNG_DLL;PNG_NO_STDIO;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				LinkIncremental="1"
+				SubSystem="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL Debug|Win32"
+			OutputDirectory=".\Win32_DLL_Debug\Test"
+			IntermediateDirectory=".\Win32_DLL_Debug\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;PNG_DLL;PNG_NO_STDIO;_CRT_SECURE_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="3"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				GenerateDebugInformation="TRUE"
+				SubSystem="1"
+				TargetMachine="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL VB|Win32"
+			OutputDirectory=".\Win32_DLL_VB\Test"
+			IntermediateDirectory=".\Win32_DLL_VB\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;PNG_DLL;PNG_NO_STDIO;PNGAPI=__stdcall;PNG_USER_PRIVATEBUILD;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="2"
+				CallingConvention="2"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\..\Win32_DLL_Release\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				LinkIncremental="1"
+				IgnoreDefaultLibraryNames="$(IntDir)\libpng16b.lib"
+				SubSystem="1"
+				TargetMachine="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Release|Win32"
+			OutputDirectory=".\Win32_LIB_Release\Test"
+			IntermediateDirectory=".\Win32_LIB_Release\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="0"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				LinkIncremental="1"
+				SubSystem="1"
+				TargetMachine="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Debug|Win32"
+			OutputDirectory=".\Win32_LIB_Debug\Test"
+			IntermediateDirectory=".\Win32_LIB_Debug\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="1"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				GenerateDebugInformation="TRUE"
+				SubSystem="1"
+				TargetMachine="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+	</Configurations>
+	<References>
+	</References>
+	<Files>
+		<Filter
+			Name="Source Files"
+			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
+			<File
+				RelativePath="..\..\pngtest.c">
+			</File>
+		</Filter>
+	</Files>
+	<Globals>
+	</Globals>
+</VisualStudioProject>
diff --git a/extern/libpng/projects/visualc71/zlib.vcproj b/extern/libpng/projects/visualc71/zlib.vcproj
new file mode 100644
index 0000000000..eb218488dc
--- /dev/null
+++ b/extern/libpng/projects/visualc71/zlib.vcproj
@@ -0,0 +1,391 @@
+<?xml version="1.0" encoding="Windows-1252"?>
+<VisualStudioProject
+	ProjectType="Visual C++"
+	Version="7.10"
+	Name="zlib">
+	<Platforms>
+		<Platform
+			Name="Win32"/>
+	</Platforms>
+	<Configurations>
+		<Configuration
+			Name="DLL Release|Win32"
+			OutputDirectory=".\Win32_DLL_Release\ZLib"
+			IntermediateDirectory=".\Win32_DLL_Release\ZLib"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="3"
+				CompileAs="1"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)\zlib1.dll"
+				LinkIncremental="1"
+				ModuleDefinitionFile="..\..\..\zlib\win32\zlib.def"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="NDEBUG"
+				Culture="1033"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL Debug|Win32"
+			OutputDirectory=".\Win32_DLL_Debug\ZLib"
+			IntermediateDirectory=".\Win32_DLL_Debug\ZLib"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="3"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="1"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)\zlib1d.dll"
+				ModuleDefinitionFile="..\..\..\zlib\win32\zlib.def"
+				GenerateDebugInformation="TRUE"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="_DEBUG"
+				Culture="1033"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Release|Win32"
+			OutputDirectory=".\Win32_LIB_Release\ZLib"
+			IntermediateDirectory=".\Win32_LIB_Release\ZLib"
+			ConfigurationType="4">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="0"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="3"
+				CompileAs="1"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLibrarianTool"
+				OutputFile="$(OutDir)\zlib.lib"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Debug|Win32"
+			OutputDirectory=".\Win32_LIB_Debug\ZLib"
+			IntermediateDirectory=".\Win32_LIB_Debug\ZLib"
+			ConfigurationType="4">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="1"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="1"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLibrarianTool"
+				OutputFile="$(OutDir)\zlibd.lib"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+	</Configurations>
+	<References>
+	</References>
+	<Files>
+		<Filter
+			Name="Source Files"
+			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
+			<File
+				RelativePath="..\..\..\zlib\adler32.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\compress.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\crc32.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\deflate.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\gzlib.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\gzclose.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\gzread.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\gzwrite.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\infback.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inffast.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inflate.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inftrees.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\trees.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\uncompr.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\win32\zlib.def">
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\zutil.c">
+			</File>
+		</Filter>
+		<Filter
+			Name="Header Files"
+			Filter="h;hpp;hxx;hm;inl">
+			<File
+				RelativePath="..\..\..\zlib\crc32.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\deflate.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inffast.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inffixed.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inflate.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inftrees.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\trees.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\zconf.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\zlib.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\zutil.h">
+			</File>
+		</Filter>
+		<Filter
+			Name="Resource Files"
+			Filter="ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe">
+			<File
+				RelativePath="..\..\..\zlib\win32\zlib1.rc">
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCResourceCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCResourceCompilerTool"/>
+				</FileConfiguration>
+			</File>
+		</Filter>
+		<Filter
+			Name="Assembler Files (Unsupported)"
+			Filter="asm;obj;c;cpp;cxx;h;hpp;hxx">
+			<File
+				RelativePath="..\..\..\zlib\contrib\masmx86\gvmat32.asm">
+				<FileConfiguration
+					Name="DLL Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\contrib\masmx86\gvmat32c.c">
+				<FileConfiguration
+					Name="DLL Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCLCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCLCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCLCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCLCompilerTool"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\contrib\masmx86\inffas32.asm">
+				<FileConfiguration
+					Name="DLL Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+			</File>
+		</Filter>
+		<File
+			RelativePath="README.txt">
+		</File>
+	</Files>
+	<Globals>
+	</Globals>
+</VisualStudioProject>
diff --git a/extern/libpng/projects/vstudio/README.txt b/extern/libpng/projects/vstudio/README.txt
new file mode 100644
index 0000000000..e28ec9549a
--- /dev/null
+++ b/extern/libpng/projects/vstudio/README.txt
@@ -0,0 +1,87 @@
+Instructions for building libpng using Microsoft Visual Studio
+==============================================================
+
+Copyright (c) 2018 Cosmin Truta
+Copyright (c) 2010,2013,2015 Glenn Randers-Pehrson
+
+This code is released under the libpng license.
+For conditions of distribution and use, see the disclaimer and license
+in png.h
+
+This directory contains a solution for building libpng under Microsoft
+Visual Studio 2010.  It may also work under later versions of Visual
+Studio.  You should be familiar with Visual Studio before using this
+solution.
+
+Initial preparations
+--------------------
+You must enter some information in zlib.props before attempting to
+build with this 'solution'.  Please read and edit zlib.props first.
+You will probably not be familiar with the contents of zlib.props -
+do not worry, it is mostly harmless.
+
+This is all you need to do to build the 'release' and 'release library'
+configurations.
+
+Debugging
+---------
+The release configurations default to /Ox optimization.  Full debugging
+information is produced (in the .pdb), but if you encounter a problem
+the optimization may make it difficult to debug.  Simply rebuild with a
+lower optimization level (e.g. /Od.)
+
+Linking your application
+------------------------
+Normally you should link against the 'release' configuration.  This
+builds a DLL for libpng with the default runtime options used by Visual
+Studio.  In particular the runtime library is the "MultiThreaded DLL"
+version.  If you use Visual Studio defaults to build your application,
+you should have no problems.
+
+If you don't use the Visual Studio defaults your application must still
+be built with the default runtime option (/MD).  If, for some reason,
+it is not then your application will crash inside libpng16.dll as soon
+as libpng tries to read from a file handle you pass in.
+
+If you do not want to use the DLL, and prefer static linking instead,
+you may choose the 'release library' configuration.  This is built with
+a non-standard runtime library - the "MultiThreaded" version.  When you
+build your application, it must be compiled with this option (/MT),
+otherwise it will not build (if you are lucky) or it will crash (if you
+are not.) See the WARNING file that is distributed with this README.
+
+Stop reading here
+-----------------
+You have enough information to build a working application.
+
+Debug versions have limited support
+-----------------------------------
+This solution includes limited support for debug versions of libpng.
+You do not need these unless your own solution itself uses debug builds
+(it is far more effective to debug on the release builds, there is no
+point building a special debug build unless you have heap corruption
+problems that you can't track down.)
+
+The debug build of libpng is minimally supported.  Support for debug
+builds of zlib is also minimal.  Please keep this in mind, if you want
+to use it.
+
+WARNING
+-------
+Libpng 1.6.x does not use the default run-time library when building
+static library builds of libpng; instead of the shared DLL runtime, it
+uses a static runtime.  If you need to change this, make sure to change
+the setting on all the relevant projects:
+
+    libpng
+    zlib
+    all the test programs
+
+The runtime library settings for each build are as follows:
+
+               Release        Debug
+    DLL         /MD            /MDd
+    Library     /MT            /MTd
+
+Also, be sure to build libpng, zlib, and your project, all for the same
+platform (e.g., 32-bit or 64-bit).
diff --git a/extern/libpng/projects/vstudio/libpng/libpng.vcxproj b/extern/libpng/projects/vstudio/libpng/libpng.vcxproj
new file mode 100644
index 0000000000..9bfb718a4a
--- /dev/null
+++ b/extern/libpng/projects/vstudio/libpng/libpng.vcxproj
@@ -0,0 +1,234 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug Library|Win32">
+      <Configuration>Debug Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|Win32">
+      <Configuration>Release Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{D6973076-9317-4EF2-A0B8-B7A18AC0713E}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>libpng</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(SolutionDir)\zlib.props" />
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <CharacterSet>MultiByte</CharacterSet>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <CharacterSet>MultiByte</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>MultiByte</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <CharacterSet>MultiByte</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildBeforeTargets>
+    </CustomBuildBeforeTargets>
+    <TargetName>$(ProjectName)16</TargetName>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildBeforeTargets />
+    <TargetName>$(ProjectName)16</TargetName>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildBeforeTargets>
+    </CustomBuildBeforeTargets>
+    <TargetName>$(ProjectName)16</TargetName>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildBeforeTargets />
+    <TargetName>$(ProjectName)16</TargetName>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>Use</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+      <TreatWChar_tAsBuiltInType>false</TreatWChar_tAsBuiltInType>
+      <PrecompiledHeaderFile>pngpriv.h</PrecompiledHeaderFile>
+      <BrowseInformation>true</BrowseInformation>
+      <CompileAs>CompileAsC</CompileAs>
+      <StringPooling>true</StringPooling>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <Optimization>Disabled</Optimization>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Windows</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>zlib.lib</AdditionalDependencies>
+      <Version>16</Version>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>Use</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+      <TreatWChar_tAsBuiltInType>false</TreatWChar_tAsBuiltInType>
+      <PrecompiledHeaderFile>pngpriv.h</PrecompiledHeaderFile>
+      <BrowseInformation>true</BrowseInformation>
+      <CompileAs>CompileAsC</CompileAs>
+      <StringPooling>true</StringPooling>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Windows</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>Use</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;_USRDLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+      <TreatWChar_tAsBuiltInType>false</TreatWChar_tAsBuiltInType>
+      <PrecompiledHeaderFile>pngpriv.h</PrecompiledHeaderFile>
+      <BrowseInformation>true</BrowseInformation>
+      <CompileAs>CompileAsC</CompileAs>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <Optimization>Full</Optimization>
+    </ClCompile>
+    <Link>
+      <SubSystem>Windows</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalDependencies>zlib.lib</AdditionalDependencies>
+      <Version>16</Version>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>Use</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+      <TreatWChar_tAsBuiltInType>false</TreatWChar_tAsBuiltInType>
+      <PrecompiledHeaderFile>pngpriv.h</PrecompiledHeaderFile>
+      <BrowseInformation>true</BrowseInformation>
+      <CompileAs>CompileAsC</CompileAs>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <Optimization>Full</Optimization>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+    </ClCompile>
+    <Link>
+      <SubSystem>Windows</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+    </Link>
+    <Lib>
+      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
+    </Lib>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="..\..\..\png.c">
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">Create</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">Create</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">Create</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">Create</PrecompiledHeader>
+    </ClCompile>
+    <ClCompile Include="..\..\..\pngerror.c" />
+    <ClCompile Include="..\..\..\pngget.c" />
+    <ClCompile Include="..\..\..\pngmem.c" />
+    <ClCompile Include="..\..\..\pngpread.c" />
+    <ClCompile Include="..\..\..\pngread.c" />
+    <ClCompile Include="..\..\..\pngrio.c" />
+    <ClCompile Include="..\..\..\pngrtran.c" />
+    <ClCompile Include="..\..\..\pngrutil.c" />
+    <ClCompile Include="..\..\..\pngset.c" />
+    <ClCompile Include="..\..\..\pngtrans.c" />
+    <ClCompile Include="..\..\..\pngwio.c" />
+    <ClCompile Include="..\..\..\pngwrite.c" />
+    <ClCompile Include="..\..\..\pngwtran.c" />
+    <ClCompile Include="..\..\..\pngwutil.c" />
+  </ItemGroup>
+  <ItemGroup>
+    <ResourceCompile Include="..\..\..\scripts\pngwin.rc">
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">true</ExcludedFromBuild>
+    </ResourceCompile>
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
diff --git a/extern/libpng/projects/vstudio/pnglibconf/pnglibconf.vcxproj b/extern/libpng/projects/vstudio/pnglibconf/pnglibconf.vcxproj
new file mode 100644
index 0000000000..efcc440ba3
--- /dev/null
+++ b/extern/libpng/projects/vstudio/pnglibconf/pnglibconf.vcxproj
@@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{EB33566E-DA7F-4D28-9077-88C0B7C77E35}</ProjectGuid>
+    <RootNamespace>pnglibconf</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>MultiByte</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(SolutionDir)\zlib.props" />
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <CustomBuildBeforeTargets>Build</CustomBuildBeforeTargets>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <Optimization>MaxSpeed</Optimization>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+    </ClCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+    </Link>
+    <CustomBuildStep>
+      <Command>copy ..\..\..\scripts\pnglibconf.h.prebuilt ..\..\..\pnglibconf.h</Command>
+    </CustomBuildStep>
+    <CustomBuildStep>
+      <Message>Generating pnglibconf.h</Message>
+    </CustomBuildStep>
+    <CustomBuildStep>
+      <Outputs>..\..\..\pnglibconf.h</Outputs>
+    </CustomBuildStep>
+    <CustomBuildStep>
+      <Inputs>..\..\..\scripts\pnglibconf.h.prebuilt</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
diff --git a/extern/libpng/projects/vstudio/pngstest/pngstest.vcxproj b/extern/libpng/projects/vstudio/pngstest/pngstest.vcxproj
new file mode 100644
index 0000000000..21810e32ab
--- /dev/null
+++ b/extern/libpng/projects/vstudio/pngstest/pngstest.vcxproj
@@ -0,0 +1,219 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug Library|Win32">
+      <Configuration>Debug Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|Win32">
+      <Configuration>Release Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{277AC57F-313B-4D06-B119-A3CDB672D2FF}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>pngstest</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(SolutionDir)\zlib.props" />
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <StringPooling>true</StringPooling>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <BrowseInformation>true</BrowseInformation>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing libpng simplified API test program</Message>
+      <Command>"$(OutDir)pngstest.exe" --strict --log --touch "$(IntDir)pngstest.out" ../../../contrib/pngsuite/basn0g01.png ../../../contrib/pngsuite/basn0g02.png ../../../contrib/pngsuite/basn0g04.png ../../../contrib/pngsuite/basn0g08.png ../../../contrib/pngsuite/basn0g16.png ../../../contrib/pngsuite/basn2c08.png ../../../contrib/pngsuite/basn2c16.png ../../../contrib/pngsuite/basn3p01.png ../../../contrib/pngsuite/basn3p02.png ../../../contrib/pngsuite/basn3p04.png ../../../contrib/pngsuite/basn3p08.png ../../../contrib/pngsuite/basn4a08.png ../../../contrib/pngsuite/basn4a16.png ../../../contrib/pngsuite/basn6a08.png ../../../contrib/pngsuite/basn6a16.png ../../../contrib/pngsuite/ftbbn0g01.png ../../../contrib/pngsuite/ftbbn0g02.png ../../../contrib/pngsuite/ftbbn0g04.png ../../../contrib/pngsuite/ftbbn2c16.png ../../../contrib/pngsuite/ftbbn3p08.png ../../../contrib/pngsuite/ftbgn2c16.png ../../../contrib/pngsuite/ftbgn3p08.png ../../../contrib/pngsuite/ftbrn2c08.png ../../../contrib/pngsuite/ftbwn0g16.png ../../../contrib/pngsuite/ftbwn3p08.png ../../../contrib/pngsuite/ftbyn3p08.png ../../../contrib/pngsuite/ftp0n0g08.png ../../../contrib/pngsuite/ftp0n2c08.png ../../../contrib/pngsuite/ftp0n3p08.png ../../../contrib/pngsuite/ftp1n3p08.png</Command>
+      <Outputs>$(IntDir)pngstest.out</Outputs>
+      <Inputs>$(OutDir)pngstest.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <StringPooling>true</StringPooling>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <BrowseInformation>true</BrowseInformation>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing libpng simplified API test program</Message>
+      <Command>"$(OutDir)pngstest.exe" --strict --log --touch "$(IntDir)pngstest.out" ../../../contrib/pngsuite/basn0g01.png ../../../contrib/pngsuite/basn0g02.png ../../../contrib/pngsuite/basn0g04.png ../../../contrib/pngsuite/basn0g08.png ../../../contrib/pngsuite/basn0g16.png ../../../contrib/pngsuite/basn2c08.png ../../../contrib/pngsuite/basn2c16.png ../../../contrib/pngsuite/basn3p01.png ../../../contrib/pngsuite/basn3p02.png ../../../contrib/pngsuite/basn3p04.png ../../../contrib/pngsuite/basn3p08.png ../../../contrib/pngsuite/basn4a08.png ../../../contrib/pngsuite/basn4a16.png ../../../contrib/pngsuite/basn6a08.png ../../../contrib/pngsuite/basn6a16.png ../../../contrib/pngsuite/ftbbn0g01.png ../../../contrib/pngsuite/ftbbn0g02.png ../../../contrib/pngsuite/ftbbn0g04.png ../../../contrib/pngsuite/ftbbn2c16.png ../../../contrib/pngsuite/ftbbn3p08.png ../../../contrib/pngsuite/ftbgn2c16.png ../../../contrib/pngsuite/ftbgn3p08.png ../../../contrib/pngsuite/ftbrn2c08.png ../../../contrib/pngsuite/ftbwn0g16.png ../../../contrib/pngsuite/ftbwn3p08.png ../../../contrib/pngsuite/ftbyn3p08.png ../../../contrib/pngsuite/ftp0n0g08.png ../../../contrib/pngsuite/ftp0n2c08.png ../../../contrib/pngsuite/ftp0n3p08.png ../../../contrib/pngsuite/ftp1n3p08.png</Command>
+      <Outputs>$(IntDir)pngstest.out</Outputs>
+      <Inputs>$(OutDir)pngstest.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <BrowseInformation>true</BrowseInformation>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing libpng simplified API test program</Message>
+      <Command>"$(OutDir)pngstest.exe" --strict --log --touch "$(IntDir)pngstest.out" ../../../contrib/pngsuite/basn0g01.png ../../../contrib/pngsuite/basn0g02.png ../../../contrib/pngsuite/basn0g04.png ../../../contrib/pngsuite/basn0g08.png ../../../contrib/pngsuite/basn0g16.png ../../../contrib/pngsuite/basn2c08.png ../../../contrib/pngsuite/basn2c16.png ../../../contrib/pngsuite/basn3p01.png ../../../contrib/pngsuite/basn3p02.png ../../../contrib/pngsuite/basn3p04.png ../../../contrib/pngsuite/basn3p08.png ../../../contrib/pngsuite/basn4a08.png ../../../contrib/pngsuite/basn4a16.png ../../../contrib/pngsuite/basn6a08.png ../../../contrib/pngsuite/basn6a16.png ../../../contrib/pngsuite/ftbbn0g01.png ../../../contrib/pngsuite/ftbbn0g02.png ../../../contrib/pngsuite/ftbbn0g04.png ../../../contrib/pngsuite/ftbbn2c16.png ../../../contrib/pngsuite/ftbbn3p08.png ../../../contrib/pngsuite/ftbgn2c16.png ../../../contrib/pngsuite/ftbgn3p08.png ../../../contrib/pngsuite/ftbrn2c08.png ../../../contrib/pngsuite/ftbwn0g16.png ../../../contrib/pngsuite/ftbwn3p08.png ../../../contrib/pngsuite/ftbyn3p08.png ../../../contrib/pngsuite/ftp0n0g08.png ../../../contrib/pngsuite/ftp0n2c08.png ../../../contrib/pngsuite/ftp0n3p08.png ../../../contrib/pngsuite/ftp1n3p08.png</Command>
+      <Outputs>$(IntDir)pngstest.out</Outputs>
+      <Inputs>$(OutDir)pngstest.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <BrowseInformation>true</BrowseInformation>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing libpng simplified API test program</Message>
+      <Command>"$(OutDir)pngstest.exe" --strict --log --touch "$(IntDir)pngstest.out" ../../../contrib/pngsuite/basn0g01.png ../../../contrib/pngsuite/basn0g02.png ../../../contrib/pngsuite/basn0g04.png ../../../contrib/pngsuite/basn0g08.png ../../../contrib/pngsuite/basn0g16.png ../../../contrib/pngsuite/basn2c08.png ../../../contrib/pngsuite/basn2c16.png ../../../contrib/pngsuite/basn3p01.png ../../../contrib/pngsuite/basn3p02.png ../../../contrib/pngsuite/basn3p04.png ../../../contrib/pngsuite/basn3p08.png ../../../contrib/pngsuite/basn4a08.png ../../../contrib/pngsuite/basn4a16.png ../../../contrib/pngsuite/basn6a08.png ../../../contrib/pngsuite/basn6a16.png ../../../contrib/pngsuite/ftbbn0g01.png ../../../contrib/pngsuite/ftbbn0g02.png ../../../contrib/pngsuite/ftbbn0g04.png ../../../contrib/pngsuite/ftbbn2c16.png ../../../contrib/pngsuite/ftbbn3p08.png ../../../contrib/pngsuite/ftbgn2c16.png ../../../contrib/pngsuite/ftbgn3p08.png ../../../contrib/pngsuite/ftbrn2c08.png ../../../contrib/pngsuite/ftbwn0g16.png ../../../contrib/pngsuite/ftbwn3p08.png ../../../contrib/pngsuite/ftbyn3p08.png ../../../contrib/pngsuite/ftp0n0g08.png ../../../contrib/pngsuite/ftp0n2c08.png ../../../contrib/pngsuite/ftp0n3p08.png ../../../contrib/pngsuite/ftp1n3p08.png</Command>
+      <Outputs>$(IntDir)pngstest.out</Outputs>
+      <Inputs>$(OutDir)pngstest.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="..\..\..\contrib\libtests\pngstest.c" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
diff --git a/extern/libpng/projects/vstudio/pngtest/pngtest.vcxproj b/extern/libpng/projects/vstudio/pngtest/pngtest.vcxproj
new file mode 100644
index 0000000000..f1df07d5c6
--- /dev/null
+++ b/extern/libpng/projects/vstudio/pngtest/pngtest.vcxproj
@@ -0,0 +1,220 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug Library|Win32">
+      <Configuration>Debug Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|Win32">
+      <Configuration>Release Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>pngtest</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(SolutionDir)\zlib.props" />
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <StringPooling>true</StringPooling>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <BrowseInformation>true</BrowseInformation>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG test program</Message>
+      <Command>"$(OutDir)pngtest.exe" ..\..\..\pngtest.png "$(IntDir)pngout.png"</Command>
+      <Outputs>$(IntDir)pngout.png</Outputs>
+      <Inputs>..\..\..\pngtest.png;$(OutDir)pngtest.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <StringPooling>true</StringPooling>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <BrowseInformation>true</BrowseInformation>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG test program</Message>
+      <Command>"$(OutDir)pngtest.exe" ..\..\..\pngtest.png "$(IntDir)pngout.png"</Command>
+      <Outputs>$(IntDir)pngout.png</Outputs>
+      <Inputs>..\..\..\pngtest.png;$(OutDir)pngtest.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <BrowseInformation>true</BrowseInformation>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG test program</Message>
+      <Command>"$(OutDir)pngtest.exe" ..\..\..\pngtest.png "$(IntDir)pngout.png"</Command>
+      <Outputs>$(IntDir)pngout.png</Outputs>
+      <Inputs>..\..\..\pngtest.png;$(OutDir)pngtest.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <BrowseInformation>true</BrowseInformation>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG test program</Message>
+      <Command>$(OutDir)pngtest.exe ..\..\..\pngtest.png $(IntDir)pngout.png</Command>
+      <Command>"$(OutDir)pngtest.exe" ..\..\..\pngtest.png "$(IntDir)pngout.png"</Command>
+      <Outputs>$(IntDir)pngout.png</Outputs>
+      <Inputs>..\..\..\pngtest.png;$(OutDir)pngtest.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="..\..\..\pngtest.c" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
diff --git a/extern/libpng/projects/vstudio/pngunknown/pngunknown.vcxproj b/extern/libpng/projects/vstudio/pngunknown/pngunknown.vcxproj
new file mode 100644
index 0000000000..409d6621d8
--- /dev/null
+++ b/extern/libpng/projects/vstudio/pngunknown/pngunknown.vcxproj
@@ -0,0 +1,219 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug Library|Win32">
+      <Configuration>Debug Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|Win32">
+      <Configuration>Release Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>pngunknown</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(SolutionDir)\zlib.props" />
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <StringPooling>true</StringPooling>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <BrowseInformation>true</BrowseInformation>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG validation program</Message>
+      <Command>"$(OutDir)pngunknown.exe" --strict --default --touch "$(IntDir)pngunknown.out" ../../../pngtest.png</Command>
+      <Outputs>$(IntDir)pngunknown.out</Outputs>
+      <Inputs>$(OutDir)pngunknown.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <StringPooling>true</StringPooling>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <BrowseInformation>true</BrowseInformation>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG validation program</Message>
+      <Command>"$(OutDir)pngunknown.exe" --strict --default --touch "$(IntDir)pngunknown.out" ../../../pngtest.png</Command>
+      <Outputs>$(IntDir)pngunknown.out</Outputs>
+      <Inputs>$(OutDir)pngunknown.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <BrowseInformation>true</BrowseInformation>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG validation program</Message>
+      <Command>"$(OutDir)pngunknown.exe" --strict --default --touch "$(IntDir)pngunknown.out" ../../../pngtest.png</Command>
+      <Outputs>$(IntDir)pngunknown.out</Outputs>
+      <Inputs>$(OutDir)pngunknown.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <BrowseInformation>true</BrowseInformation>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG validation program</Message>
+      <Command>"$(OutDir)pngunknown.exe" --strict --default --touch "$(IntDir)pngunknown.out" ../../../pngtest.png</Command>
+      <Outputs>$(IntDir)pngunknown.out</Outputs>
+      <Inputs>$(OutDir)pngunknown.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="..\..\..\contrib\libtests\pngunknown.c" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
diff --git a/extern/libpng/projects/vstudio/pngvalid/pngvalid.vcxproj b/extern/libpng/projects/vstudio/pngvalid/pngvalid.vcxproj
new file mode 100644
index 0000000000..c117d2910a
--- /dev/null
+++ b/extern/libpng/projects/vstudio/pngvalid/pngvalid.vcxproj
@@ -0,0 +1,219 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug Library|Win32">
+      <Configuration>Debug Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|Win32">
+      <Configuration>Release Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>pngvalid</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(SolutionDir)\zlib.props" />
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <CustomBuildAfterTargets />
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <StringPooling>true</StringPooling>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <BrowseInformation>true</BrowseInformation>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG validation program</Message>
+      <Command>"$(OutDir)pngvalid.exe" --touch "$(IntDir)pngvalid.out"</Command>
+      <Outputs>$(IntDir)pngvalid.out</Outputs>
+      <Inputs>$(OutDir)pngvalid.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <MinimalRebuild>false</MinimalRebuild>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <StringPooling>true</StringPooling>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <BrowseInformation>true</BrowseInformation>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG validation program</Message>
+      <Command>"$(OutDir)pngvalid.exe" --touch "$(IntDir)pngvalid.out"</Command>
+      <Outputs>$(IntDir)pngvalid.out</Outputs>
+      <Inputs>$(OutDir)pngvalid.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <BrowseInformation>true</BrowseInformation>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG validation program</Message>
+      <Command>"$(OutDir)pngvalid.exe" --touch "$(IntDir)pngvalid.out"</Command>
+      <Outputs>$(IntDir)pngvalid.out</Outputs>
+      <Inputs>$(OutDir)pngvalid.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <FunctionLevelLinking>false</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <CompileAsManaged>false</CompileAsManaged>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <StringPooling>true</StringPooling>
+      <MinimalRebuild>false</MinimalRebuild>
+      <BrowseInformation>true</BrowseInformation>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <FloatingPointExceptions>false</FloatingPointExceptions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
+      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+    </Link>
+    <CustomBuildStep>
+      <Message>Executing PNG validation program</Message>
+      <Command>"$(OutDir)pngvalid.exe" --touch "$(IntDir)pngvalid.out"</Command>
+      <Outputs>$(IntDir)pngvalid.out</Outputs>
+      <Inputs>$(OutDir)pngvalid.exe</Inputs>
+    </CustomBuildStep>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="..\..\..\contrib\libtests\pngvalid.c" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
diff --git a/extern/libpng/projects/vstudio/vstudio.sln b/extern/libpng/projects/vstudio/vstudio.sln
new file mode 100644
index 0000000000..af0b1bab59
--- /dev/null
+++ b/extern/libpng/projects/vstudio/vstudio.sln
@@ -0,0 +1,109 @@
+Microsoft Visual Studio Solution File, Format Version 11.00
+# Visual Studio 2010
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "zlib", "zlib\zlib.vcxproj", "{60F89955-91C6-3A36-8000-13C592FEC2DF}"
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pnglibconf", "pnglibconf\pnglibconf.vcxproj", "{EB33566E-DA7F-4D28-9077-88C0B7C77E35}"
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "libpng", "libpng\libpng.vcxproj", "{D6973076-9317-4EF2-A0B8-B7A18AC0713E}"
+	ProjectSection(ProjectDependencies) = postProject
+		{60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
+	EndProjectSection
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngtest", "pngtest\pngtest.vcxproj", "{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}"
+	ProjectSection(ProjectDependencies) = postProject
+		{60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E} = {D6973076-9317-4EF2-A0B8-B7A18AC0713E}
+	EndProjectSection
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngvalid", "pngvalid\pngvalid.vcxproj", "{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}"
+	ProjectSection(ProjectDependencies) = postProject
+		{60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E} = {D6973076-9317-4EF2-A0B8-B7A18AC0713E}
+	EndProjectSection
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngstest", "pngstest\pngstest.vcxproj", "{277AC57F-313B-4D06-B119-A3CDB672D2FF}"
+	ProjectSection(ProjectDependencies) = postProject
+		{60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E} = {D6973076-9317-4EF2-A0B8-B7A18AC0713E}
+	EndProjectSection
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngunknown", "pngunknown\pngunknown.vcxproj", "{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}"
+	ProjectSection(ProjectDependencies) = postProject
+		{60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E} = {D6973076-9317-4EF2-A0B8-B7A18AC0713E}
+	EndProjectSection
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug Library|Win32 = Debug Library|Win32
+		Debug|Win32 = Debug|Win32
+		Release Library|Win32 = Release Library|Win32
+		Release|Win32 = Release|Win32
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Debug Library|Win32.Build.0 = Debug Library|Win32
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Debug|Win32.ActiveCfg = Debug|Win32
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Debug|Win32.Build.0 = Debug|Win32
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Release Library|Win32.ActiveCfg = Release Library|Win32
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Release Library|Win32.Build.0 = Release Library|Win32
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Release|Win32.ActiveCfg = Release|Win32
+		{D6973076-9317-4EF2-A0B8-B7A18AC0713E}.Release|Win32.Build.0 = Release|Win32
+		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
+		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Debug Library|Win32.Build.0 = Debug Library|Win32
+		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Debug|Win32.ActiveCfg = Debug|Win32
+		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Debug|Win32.Build.0 = Debug|Win32
+		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release Library|Win32.ActiveCfg = Release Library|Win32
+		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release Library|Win32.Build.0 = Release Library|Win32
+		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release|Win32.ActiveCfg = Release|Win32
+		{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release|Win32.Build.0 = Release|Win32
+		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
+		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug Library|Win32.Build.0 = Debug Library|Win32
+		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug|Win32.ActiveCfg = Debug|Win32
+		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug|Win32.Build.0 = Debug|Win32
+		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Release Library|Win32.ActiveCfg = Release Library|Win32
+		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Release Library|Win32.Build.0 = Release Library|Win32
+		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Release|Win32.ActiveCfg = Release|Win32
+		{60F89955-91C6-3A36-8000-13C592FEC2DF}.Release|Win32.Build.0 = Release|Win32
+		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
+		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug Library|Win32.Build.0 = Debug Library|Win32
+		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug|Win32.ActiveCfg = Debug|Win32
+		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug|Win32.Build.0 = Debug|Win32
+		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Release Library|Win32.ActiveCfg = Release Library|Win32
+		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Release Library|Win32.Build.0 = Release Library|Win32
+		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Release|Win32.ActiveCfg = Release|Win32
+		{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Release|Win32.Build.0 = Release|Win32
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Debug Library|Win32.ActiveCfg = Release|Win32
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Debug Library|Win32.Build.0 = Release|Win32
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Debug|Win32.ActiveCfg = Release|Win32
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Debug|Win32.Build.0 = Release|Win32
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release Library|Win32.ActiveCfg = Release|Win32
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release Library|Win32.Build.0 = Release|Win32
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release|Win32.ActiveCfg = Release|Win32
+		{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release|Win32.Build.0 = Release|Win32
+		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
+		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug Library|Win32.Build.0 = Debug Library|Win32
+		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug|Win32.ActiveCfg = Debug|Win32
+		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug|Win32.Build.0 = Debug|Win32
+		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release Library|Win32.ActiveCfg = Release Library|Win32
+		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release Library|Win32.Build.0 = Release Library|Win32
+		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release|Win32.ActiveCfg = Release|Win32
+		{277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release|Win32.Build.0 = Release|Win32
+		{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
+		{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}.Debug Library|Win32.Build.0 = Debug Library|Win32
+		{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}.Debug|Win32.ActiveCfg = Debug|Win32
+		{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}.Debug|Win32.Build.0 = Debug|Win32
+		{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}.Release Library|Win32.ActiveCfg = Release Library|Win32
+		{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}.Release Library|Win32.Build.0 = Release Library|Win32
+		{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}.Release|Win32.ActiveCfg = Release|Win32
+		{C5D3156C-8C8C-4936-B35F-2B829BA36FEC}.Release|Win32.Build.0 = Release|Win32
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal
diff --git a/extern/libpng/projects/vstudio/zlib.props b/extern/libpng/projects/vstudio/zlib.props
new file mode 100644
index 0000000000..8786279661
--- /dev/null
+++ b/extern/libpng/projects/vstudio/zlib.props
@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+ * zlib.props - location of zlib source
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+
+ * You may need to edit this file in order to update the location
+ * of the zlib source code.
+ -->
+
+<Project ToolsVersion="4.0"
+   xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup Label="Globals">
+    <!-- Place the name of the directory containing the source of zlib used for
+	 debugging in this property.
+
+         The directory need only contain the '.c' and '.h' files from the
+	 source.
+
+	 If you use a relative directory name (as below) then it must be
+	 relative to the project directories; these are one level deeper than
+	 the directories containing this file.
+
+	 If the version of zlib you use does not match that used when the
+	 distribution was built you will get warnings from pngtest that the zlib
+	 versions do not match.  The zlib version used in this build is recorded
+	 below:
+     -->
+    <ZLibSrcDir>..\..\..\..\zlib</ZLibSrcDir>
+
+    <!-- The following line allows compilation for an ARM target with Visual
+         Studio 2012.  Notice that this is not supported by the Visual Studio
+         2012 IDE and that the programs that result cannot be run unless they
+         signed by Microsoft.  This is therefore untested; only Microsoft can
+         test it:
+     -->
+    <WindowsSDKDesktopARMSupport>true</WindowsSDKDesktopARMSupport>
+
+    <!-- The following lines provide a global (solution level) control of the
+         warnings issued by the compiler, these are used in the individual
+         project files (*/*.vcxproj) with, for zlib, some extra disables.
+
+         Different versions of Visual Studio may require different settings,
+         these settings work with Visual Studio 2013.  Just set
+         TreatWarningAsError to false to check the build without failing on
+         errors.
+     -->
+   <WarningLevel>EnableAllWarnings</WarningLevel>
+   <TreatWarningAsError>true</TreatWarningAsError>
+   <DisableSpecificWarnings>4255;4668;4710;4711;4746;4820;4996</DisableSpecificWarnings>
+  </PropertyGroup>
+</Project>
diff --git a/extern/libpng/projects/vstudio/zlib/zlib.vcxproj b/extern/libpng/projects/vstudio/zlib/zlib.vcxproj
new file mode 100644
index 0000000000..0df16db345
--- /dev/null
+++ b/extern/libpng/projects/vstudio/zlib/zlib.vcxproj
@@ -0,0 +1,175 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug Library|Win32">
+      <Configuration>Debug Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|Win32">
+      <Configuration>Release Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="$(ZLibSrcDir)\adler32.c" />
+    <ClCompile Include="$(ZLibSrcDir)\compress.c" />
+    <ClCompile Include="$(ZLibSrcDir)\crc32.c" />
+    <ClCompile Include="$(ZLibSrcDir)\deflate.c" />
+    <ClCompile Include="$(ZLibSrcDir)\infback.c" />
+    <ClCompile Include="$(ZLibSrcDir)\inffast.c" />
+    <ClCompile Include="$(ZLibSrcDir)\inflate.c" />
+    <ClCompile Include="$(ZLibSrcDir)\inftrees.c" />
+    <ClCompile Include="$(ZLibSrcDir)\trees.c" />
+    <ClCompile Include="$(ZLibSrcDir)\uncompr.c" />
+    <ClCompile Include="$(ZLibSrcDir)\zutil.c" />
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{60F89955-91C6-3A36-8000-13C592FEC2DF}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>zlib</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(SolutionDir)\zlib.props" />
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <ClCompile>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+    </ClCompile>
+    <Link>
+      <TargetMachine>MachineX86</TargetMachine>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <TargetMachine>MachineX86</TargetMachine>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+    </ClCompile>
+    <Link>
+      <TargetMachine>MachineX86</TargetMachine>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+    <Lib>
+      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
+    </Lib>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+    </ClCompile>
+    <Link>
+      <TargetMachine>MachineX86</TargetMachine>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+    </Link>
+    <Lib>
+      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
+    </Lib>
+  </ItemDefinitionGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
diff --git a/extern/libpng/scripts/README.txt b/extern/libpng/scripts/README.txt
new file mode 100644
index 0000000000..3d911ef2f6
--- /dev/null
+++ b/extern/libpng/scripts/README.txt
@@ -0,0 +1,79 @@
+
+Makefiles for libpng
+
+pnglibconf.h.prebuilt  =>  Configuration settings
+ makefile.linux    =>  Linux/ELF makefile
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.linux-opt=>  Linux/ELF makefile with hardware optimizations on
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
+ makefile.acorn    =>  Acorn makefile
+ makefile.aix      =>  AIX/gcc makefile
+ makefile.amiga    =>  Amiga makefile
+ makefile.atari    =>  Atari makefile
+ makefile.bc32     =>  32-bit Borland C++ (all modules compiled in C mode)
+ makefile.beos     =>  BeOS makefile
+ makefile.cegcc    =>  minge32ce for Windows CE makefile
+ makefile.darwin   =>  Darwin makefile, for macOS (formerly Mac OS X)
+ makefile.dec      =>  DEC Alpha UNIX makefile
+ makefile.dj2      =>  DJGPP 2 makefile
+ makefile.freebsd  =>  FreeBSD makefile
+ makefile.gcc      =>  Generic gcc makefile
+ makefile.hpgcc    =>  HPUX makefile using gcc
+ makefile.hpux     =>  HPUX (10.20 and 11.00) makefile
+ makefile.hp64     =>  HPUX (10.20 and 11.00) makefile, 64-bit
+ makefile.ibmc     =>  IBM C/C++ version 3.x for Win32 and OS/2 (static)
+ makefile.intel    =>  Intel C/C++ version 4.0 and later
+ makefile.mips     =>  MIPS makefile
+ makefile.netbsd   =>  NetBSD/cc makefile, makes shared libpng.so
+ makefile.openbsd  =>  OpenBSD makefile
+ makefile.sco      =>  SCO OSr5 ELF and Unixware 7 with Native cc
+ makefile.sggcc    =>  Silicon Graphics makefile
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
+ makefile.solaris  =>  Solaris 2.X makefile
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.so9      =>  Solaris 9 makefile
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
+ makefile.sunos    =>  Sun makefile
+ makefile.32sunu   =>  Sun Ultra 32-bit makefile
+ makefile.64sunu   =>  Sun Ultra 64-bit makefile
+ makefile.vcwin32  =>  makefile for Microsoft Visual C++ 4.0 and later
+ makevms.com       =>  VMS build script
+ smakefile.ppc     =>  AMIGA smakefile for SAS C V6.58/7.00 PPC compiler
+                       (Requires SCOPTIONS, copied from scripts/SCOPTIONS.ppc)
+
+Other supporting scripts:
+ README.txt        =>  This file
+ descrip.mms       =>  VMS makefile for MMS or MMK
+ libpng-config-body.in => used by several makefiles to create libpng-config
+ libpng-config-head.in => used by several makefiles to create libpng-config
+ libpng.pc.in      =>  Used by several makefiles to create libpng.pc
+ pngwin.rc         =>  Used by the visualc71 project
+ pngwin.def        =>  Used by makefile.os2
+ pngwin.dfn        =>  Used to maintain pngwin.def
+ SCOPTIONS.ppc     =>  Used with smakefile.ppc
+
+ checksym.awk      =>  Used for maintaining pnglibconf.h
+ def.dfn           =>  Used for maintaining pnglibconf.h
+ options.awk       =>  Used for maintaining pnglibconf.h
+ pnglibconf.dfa    =>  Used for maintaining pnglibconf.h
+ pnglibconf.mak    =>  Used for maintaining pnglibconf.h
+ sym.dfn           =>  Used for symbol versioning
+ symbols.def       =>  Used for symbol versioning
+ symbols.dfn       =>  Used for symbol versioning
+ vers.dfn          =>  Used for symbol versioning
+
+ libtool.m4        =>  Used by autoconf tools
+ ltoptions.m4      =>  Used by autoconf tools
+ ltsugar.m4        =>  Used by autoconf tools
+ ltversion.m4      =>  Used by autoconf tools
+ lt~obsolete.m4    =>  Used by autoconf tools
+
+ intprefix.dfn     =>  Used by autoconf tools
+ macro.lst         =>  Used by autoconf tools
+ prefix.dfn        =>  Used by autoconf tools
+
+
+Further information can be found in comments in the individual makefiles.
diff --git a/extern/libpng/scripts/SCOPTIONS.ppc b/extern/libpng/scripts/SCOPTIONS.ppc
new file mode 100644
index 0000000000..2c3503e9eb
--- /dev/null
+++ b/extern/libpng/scripts/SCOPTIONS.ppc
@@ -0,0 +1,7 @@
+OPTIMIZE
+OPTPEEP
+OPTTIME
+OPTSCHED
+AUTOREGISTER
+PARMS=REGISTERS
+INCLUDEDIR=hlp:ppc/include
diff --git a/extern/libpng/scripts/checksym.awk b/extern/libpng/scripts/checksym.awk
new file mode 100755
index 0000000000..fe3af55e05
--- /dev/null
+++ b/extern/libpng/scripts/checksym.awk
@@ -0,0 +1,173 @@
+#!/bin/awk -f
+# Check a list of symbols against the master definition
+# (official) list.  Arguments:
+#
+# awk -f checksym.awk official-def list-to-check
+#
+# Output is a file in the current directory called 'symbols.new',
+# the value of the awk variable "of" (which can be changed on the
+# command line if required.)  stdout holds error messages.  Error
+# code indicates success or failure.
+#
+# NOTE: this is a pure, old fashioned, awk script.  It will
+# work with any awk
+
+BEGIN{
+   err=0
+   master=""        # master file
+   official[1] = "" # defined symbols from master file
+   symbol[1] = ""   # defined symbols from png.h
+   removed[1] = ""  # removed symbols from png.h
+   lasto = 0        # last ordinal value from png.h
+   mastero = 0      # highest ordinal in master file
+   symbolo = 0      # highest ordinal in png.h
+   missing = "error"# log an error on missing symbols
+   of="symbols.new" # default to a fixed name
+}
+
+# Read existing definitions from the master file (the first
+# file on the command line.)  This must be a def file and it
+# has definition lines (others are ignored) of the form:
+#
+#   symbol @ordinal
+#
+master == "" {
+   master = FILENAME
+}
+FILENAME==master && NF==2 && $2~/^@/ && $1!~/^;/ {
+   o=0+substr($2,2)
+   if (o > 0) {
+      if (official[o] == "") {
+         official[o] = $1
+         if (o > mastero) mastero = o
+         next
+      } else
+         print master ": duplicated symbol:", official[o] ":", $0
+   } else
+      print master ": bad export line format:", $0
+   err = 1
+}
+FILENAME==master && $1==";missing" && NF==2{
+   # This allows the master file to control how missing symbols
+   # are handled; symbols that aren't in either the master or
+   # the new file.  Valid values are 'ignore', 'warning' and
+   # 'error'
+   missing = $2
+}
+FILENAME==master {
+   next
+}
+
+# Read new definitions, these are free form but the lines must
+# just be symbol definitions.  Lines will be commented out for
+# 'removed' symbols, introduced in png.h using PNG_REMOVED rather
+# than PNG_EXPORT.  Use symbols.dfn or pngwin.dfn to generate the
+# input file.
+#
+#  symbol @ordinal   # two fields, exported symbol
+#  ; symbol @ordinal # three fields, removed symbol
+#  ; @ordinal        # two fields, the last ordinal
+NF==2 && $1 == ";" && $2 ~ /^@[1-9][0-9]*$/ { # last ordinal
+   o=0+substr($2,2)
+   if (lasto == 0 || lasto == o)
+      lasto=o
+   else {
+      print "png.h: duplicated last ordinal:", lasto, o
+      err = 1
+   }
+   next
+}
+NF==3 && $1 == ";" && $3 ~ /^@[1-9][0-9]*$/ { # removed symbol
+   o=0+substr($3,2)
+   if (removed[o] == "" || removed[o] == $2) {
+      removed[o] = $2
+      if (o > symbolo) symbolo = o
+   } else {
+      print "png.h: duplicated removed symbol", o ": '" removed[o] "' != '" $2 "'"
+      err = 1
+   }
+   next
+}
+NF==2 && $2 ~ /^@[1-9][0-9]*$/ { # exported symbol
+   o=0+substr($2,2)
+   if (symbol[o] == "" || symbol[o] == $1) {
+      symbol[o] = $1
+      if (o > symbolo) symbolo = o
+   } else {
+      print "png.h: duplicated symbol", o ": '" symbol[o] "' != '" $1 "'"
+      err = 1
+   }
+}
+{
+   next # skip all other lines
+}
+
+# At the end check for symbols marked as both duplicated and removed
+END{
+   if (symbolo > lasto) {
+      print "highest symbol ordinal in png.h,", symbolo ", exceeds last ordinal from png.h", lasto
+      err = 1
+   }
+   if (mastero > lasto) {
+      print "highest symbol ordinal in", master ",", mastero ", exceeds last ordinal from png.h", lasto
+      err = 1
+   }
+   unexported=0
+   # Add a standard header to symbols.new:
+   print ";Version INSERT-VERSION-HERE" >of
+   print ";--------------------------------------------------------------" >of
+   print "; LIBPNG symbol list as a Win32 DEF file" >of
+   print "; Contains all the symbols that can be exported from libpng" >of
+   print ";--------------------------------------------------------------" >of
+   print "LIBRARY" >of
+   print "" >of
+   print "EXPORTS" >of
+
+   for (o=1; o<=lasto; ++o) {
+      if (symbol[o] == "" && removed[o] == "") {
+         if (unexported == 0) unexported = o
+         if (official[o] == "") {
+            # missing in export list too, so ok
+            if (o < lasto) continue
+         }
+      }
+      if (unexported != 0) {
+         # Symbols in the .def but not in the new file are errors, but
+         # the 'unexported' symbols aren't in either.  By default this
+         # is an error too (see the setting of 'missing' at the start),
+         # but this can be reset on the command line or by stuff in the
+         # file - see the comments above.
+         if (missing != "ignore") {
+            if (o-1 > unexported)
+               print "png.h:", missing ": missing symbols:", unexported "-" o-1
+            else
+               print "png.h:", missing ": missing symbol:", unexported
+            if (missing != "warning")
+               err = 1
+         }
+         unexported = 0
+      }
+      if (symbol[o] != "" && removed[o] != "") {
+         print "png.h: symbol", o, "both exported as '" symbol[o] "' and removed as '" removed[o] "'"
+         err = 1
+      } else if (symbol[o] != official[o]) {
+         # either the symbol is missing somewhere or it changed
+         err = 1
+         if (symbol[o] == "")
+            print "png.h: symbol", o, "is exported as '" official[o] "' in", master
+         else if (official[o] == "")
+            print "png.h: exported symbol", o, "'" symbol[o] "' not present in", master
+         else
+            print "png.h: exported symbol", o, "'" symbol[o] "' exists as '" official[o] "' in", master
+      }
+
+      # Finally generate symbols.new
+      if (symbol[o] != "")
+         print " " symbol[o], "@" o > of
+   }
+
+   if (err != 0) {
+      print "*** A new list is in", of, "***"
+      exit 1
+   }
+}
diff --git a/extern/libpng/scripts/descrip.mms b/extern/libpng/scripts/descrip.mms
new file mode 100644
index 0000000000..a3aefbf4c8
--- /dev/null
+++ b/extern/libpng/scripts/descrip.mms
@@ -0,0 +1,52 @@
+
+cc_defs = /inc=$(ZLIBSRC)
+c_deb =
+
+.ifdef __DECC__
+pref = /prefix=all
+.endif
+
+
+
+OBJS = png.obj, pngset.obj, pngget.obj, pngrutil.obj, pngtrans.obj,\
+	pngwutil.obj, pngread.obj, pngmem.obj, pngwrite.obj, pngrtran.obj,\
+	pngwtran.obj, pngrio.obj, pngwio.obj, pngerror.obj, pngpread.obj
+
+
+CFLAGS= $(C_DEB) $(CC_DEFS) $(PREF)
+
+all : pngtest.exe libpng.olb
+	@ write sys$output " pngtest available"
+
+libpng.olb : libpng.olb($(OBJS))
+	@ write sys$output " libpng available"
+
+
+pngtest.exe : pngtest.obj libpng.olb
+              link pngtest,libpng.olb/lib,$(ZLIBSRC)libz.olb/lib
+
+test : pngtest.exe
+   run pngtest
+
+clean :
+	delete *.obj;*,*.exe;
+
+
+# Other dependencies.
+png.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngpread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngset.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngget.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngerror.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngmem.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngtrans.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwrite.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+
+pngtest.obj : png.h, pngconf.h, pnglibconf.h
diff --git a/extern/libpng/scripts/dfn.awk b/extern/libpng/scripts/dfn.awk
new file mode 100755
index 0000000000..346b9db7d5
--- /dev/null
+++ b/extern/libpng/scripts/dfn.awk
@@ -0,0 +1,203 @@
+#!/bin/awk -f
+# scripts/dfn.awk - process a .dfn file
+#
+# last changed in libpng version 1.5.19 - August 21, 2014
+#
+# Copyright (c) 2013-2014 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# The output of this script is written to the file given by
+# the variable 'out', which should be set on the command line.
+# Error messages are printed to stdout and if any are printed
+# the script will exit with error code 1.
+
+BEGIN{
+   out="/dev/null"       # as a flag
+   out_count=0           # count of output lines
+   err=0                 # set if an error occurred
+   sort=0                # sort the output
+   array[""]=""
+}
+
+# The output file must be specified before any input:
+NR==1 && out == "/dev/null" {
+   print "out=output.file must be given on the command line"
+   # but continue without setting the error code; this allows the
+   # script to be checked easily
+}
+
+# Output can be sorted; two lines are recognized
+$1 == "PNG_DFN_START_SORT"{
+   sort=0+$2
+   next
+}
+
+$1 ~ /^PNG_DFN_END_SORT/{
+   # Do a very simple, slow, sort; notice that blank lines won't be
+   # output by this
+   for (entry in array) {
+      while (array[entry] != "") {
+         key = entry
+         value = array[key]
+         array[key] = ""
+
+         for (alt in array) {
+            if (array[alt] != "" && alt < key) {
+               array[key] = value
+               value = array[alt]
+               key = alt
+               array[alt] = ""
+            }
+         }
+
+         print value >out
+      }
+   }
+   sort=0
+   next
+}
+
+/^[^"]*PNG_DFN *".*"[^"]*$/{
+   # A definition line, apparently correctly formatted; extract the
+   # definition then replace any doubled "" that remain with a single
+   # double quote.  Notice that the original doubled double quotes
+   # may have been split by tokenization
+   #
+   # Sometimes GCC splits the PNG_DFN lines; we know this has happened
+   # if the quotes aren't closed and must read another line.  In this
+   # case it is essential to reject lines that start with '#' because those
+   # are introduced #line directives.
+   orig=$0
+   line=$0
+   lineno=FNR
+   if (lineno == "") lineno=NR
+
+   if (sub(/^[^"]*PNG_DFN *"/,"",line) != 1) {
+	print "line", lineno ": processing failed:"
+	print orig
+	err=1
+       next
+   } else {
+	++out_count
+   }
+
+   # Now examine quotes within the value:
+   #
+   #   @" - delete this and any following spaces
+   #   "@ - delete this and any preceding spaces
+   #   @' - replace this by a double quote
+   #
+   # This allows macro substitution by the C compiler thus:
+   #
+   #   #define first_name John
+   #   #define last_name Smith
+   #
+   #	PNG_DFN"#define name @'@" first_name "@ @" last_name "@@'"
+   #
+   # Might get C preprocessed to:
+   #
+   #   PNG_DFN "#define foo @'@" John "@ @" Smith "@@'"
+   #
+   # Which this script reduces to:
+   #
+   #	#define name "John Smith"
+   #
+   while (1) {
+      # While there is an @" remove it and the next "@
+      if (line ~ /@"/) {
+         if (line ~ /@".*"@/) {
+            # Do this special case first to avoid swallowing extra spaces
+            # before or after the @ stuff:
+            if (!sub(/@" *"@/, "", line)) {
+               # Ok, do it in pieces - there has to be a non-space between the
+               # two.  NOTE: really weird things happen if a leading @" is
+               # lost - the code will error out below (I believe).
+               if (!sub(/@" */, "", line) || !sub(/ *"@/, "", line)) {
+                  print "line", lineno, ": internal error:", orig
+                  exit 1
+               }
+            }
+         }
+
+         # There is no matching "@.  Assume a split line
+         else while (1) {
+            if (getline nextline) {
+               # If the line starts with '#' it is a preprocesor line directive
+               # from cc -E; skip it:
+               if (nextline !~ /^#/) {
+                  line = line " " nextline
+                  break
+               }
+            } else {
+               # This is end-of-input - probably a missing "@ on the first line:
+               print "line", lineno ": unbalanced @\" ... \"@ pair"
+               err=1
+               next
+            }
+         }
+
+         # Keep going until all the @" have gone
+         continue
+      }
+
+      # Attempt to remove a trailing " (not preceded by '@') - if this can
+      # be done, stop now; if not assume a split line again
+      if (sub(/"[^"]*$/, "", line))
+         break
+
+      # Read another line
+      while (1) {
+         if (getline nextline) {
+            if (nextline !~ /^#/) {
+               line = line " " nextline
+               # Go back to stripping @" "@ pairs
+               break
+            }
+         } else {
+            print "line", lineno ": unterminated PNG_DFN string"
+            err=1
+            next
+         }
+      }
+   }
+
+   # Put any needed double quotes in (at the end, because these would otherwise
+   # interfere with the processing above.)
+   gsub(/@'/,"\"", line)
+
+   # Remove any trailing spaces (not really required, but for
+   # editorial consistency
+   sub(/ *$/, "", line)
+
+   # Remove trailing CR
+   sub(/
$/, "", line)
+
+   if (sort) {
+      if (split(line, parts) < sort) {
+         print "line", lineno ": missing sort field:", line
+         err=1
+      } else
+         array[parts[sort]] = line
+   }
+
+   else
+      print line >out
+   next
+}
+
+/PNG_DFN/{
+   print "line", NR, "incorrectly formatted PNG_DFN line:"
+   print $0
+   err = 1
+}
+
+END{
+   if (out_count > 0 || err > 0)
+	exit err
+
+   print "no definition lines found"
+   exit 1
+}
diff --git a/extern/libpng/scripts/genchk.cmake.in b/extern/libpng/scripts/genchk.cmake.in
new file mode 100644
index 0000000000..ab3b9d7469
--- /dev/null
+++ b/extern/libpng/scripts/genchk.cmake.in
@@ -0,0 +1,37 @@
+# genchk.cmake.in
+# Generate .chk from .out with awk (generic), based upon the automake logic.
+
+# Copyright (C) 2016 Glenn Randers-Pehrson
+# Written by Roger Leigh, 2016
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Variables substituted from CMakeLists.txt
+set(SRCDIR "@CMAKE_CURRENT_SOURCE_DIR@")
+
+set(AWK "@AWK@")
+
+get_filename_component(INPUTEXT "${INPUT}" EXT)
+get_filename_component(OUTPUTEXT "${OUTPUT}" EXT)
+get_filename_component(INPUTBASE "${INPUT}" NAME_WE)
+get_filename_component(OUTPUTBASE "${OUTPUT}" NAME_WE)
+get_filename_component(INPUTDIR "${INPUT}" PATH)
+get_filename_component(OUTPUTDIR "${OUTPUT}" PATH)
+
+if("${INPUTEXT}" STREQUAL ".out" AND "${OUTPUTEXT}" STREQUAL ".chk")
+  # Generate .chk from .out with awk (generic)
+  file(REMOVE "${OUTPUT}" "${OUTPUTDIR}/${OUTPUTBASE}.new")
+  execute_process(COMMAND "${AWK}" -f "${SRCDIR}/scripts/checksym.awk"
+                          "${SRCDIR}/scripts/${INPUTBASE}.def"
+                          "of=${OUTPUTDIR}/${OUTPUTBASE}.new"
+                          "${INPUT}"
+                  RESULT_VARIABLE AWK_FAIL)
+  if(AWK_FAIL)
+    message(FATAL_ERROR "Failed to generate ${OUTPUTDIR}/${OUTPUTBASE}.new")
+  endif()
+  file(RENAME "${OUTPUTDIR}/${OUTPUTBASE}.new" "${OUTPUT}")
+else()
+  message(FATAL_ERROR "Unsupported conversion: ${INPUTEXT} to ${OUTPUTEXT}")
+endif()
diff --git a/extern/libpng/scripts/genout.cmake.in b/extern/libpng/scripts/genout.cmake.in
new file mode 100644
index 0000000000..01f12de2fc
--- /dev/null
+++ b/extern/libpng/scripts/genout.cmake.in
@@ -0,0 +1,93 @@
+# genout.cmake.in
+# Generate .out from .c with awk (generic), based upon the automake logic.
+
+# Copyright (C) 2016 Glenn Randers-Pehrson
+# Written by Roger Leigh, 2016
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Variables substituted from CMakeLists.txt
+set(SRCDIR "@CMAKE_CURRENT_SOURCE_DIR@")
+set(BINDIR "@CMAKE_CURRENT_BINARY_DIR@")
+
+set(AWK "@AWK@")
+set(CMAKE_C_COMPILER "@CMAKE_C_COMPILER@")
+set(CMAKE_C_FLAGS @CMAKE_C_FLAGS@)
+set(INCDIR "@CMAKE_CURRENT_BINARY_DIR@")
+set(PNG_PREFIX "@PNG_PREFIX@")
+set(PNGLIB_MAJOR "@PNGLIB_MAJOR@")
+set(PNGLIB_MINOR "@PNGLIB_MINOR@")
+set(PNGLIB_VERSION "@PNGLIB_VERSION@")
+set(ZLIBINCDIR "@ZLIB_INCLUDE_DIR@")
+
+set(PLATFORM_C_FLAGS)
+if(APPLE)
+  set(CMAKE_OSX_ARCHITECTURES "@CMAKE_OSX_ARCHITECTURES@")
+  set(CMAKE_OSX_SYSROOT "@CMAKE_OSX_SYSROOT@")
+  if(CMAKE_OSX_ARCHITECTURES)
+    set(PLATFORM_C_FLAGS ${PLATFORM_C_FLAGS} -arch ${CMAKE_OSX_ARCHITECTURES})
+  endif()
+  if(CMAKE_OSX_SYSROOT)
+    set(PLATFORM_C_FLAGS ${PLATFORM_C_FLAGS} -isysroot ${CMAKE_OSX_SYSROOT})
+  endif()
+endif()
+
+get_filename_component(INPUTEXT "${INPUT}" EXT)
+get_filename_component(OUTPUTEXT "${OUTPUT}" EXT)
+get_filename_component(INPUTBASE "${INPUT}" NAME_WE)
+get_filename_component(OUTPUTBASE "${OUTPUT}" NAME_WE)
+get_filename_component(INPUTDIR "${INPUT}" PATH)
+get_filename_component(OUTPUTDIR "${OUTPUT}" PATH)
+
+if ("${INPUTEXT}" STREQUAL ".c" AND "${OUTPUTEXT}" STREQUAL ".out")
+  get_filename_component(GENDIR "${OUTPUT}" PATH)
+  file(MAKE_DIRECTORY "${GENDIR}")
+
+  file(REMOVE "${OUTPUT}.tf1" "${OUTPUT}.tf2")
+
+  set(INCLUDES "-I${INCDIR}")
+  if(ZLIBINCDIR)
+    foreach(dir ${ZLIBINCDIR})
+      list(APPEND INCLUDES "-I${dir}")
+    endforeach()
+  endif()
+
+  if(PNG_PREFIX)
+    set(PNG_PREFIX_DEF "-DPNG_PREFIX=${PNG_PREFIX}")
+  endif()
+
+  execute_process(COMMAND "${CMAKE_C_COMPILER}" "-E"
+                          ${CMAKE_C_FLAGS}
+                          ${PLATFORM_C_FLAGS}
+                          "-I${SRCDIR}"
+                          "-I${BINDIR}"
+                          ${INCLUDES}
+                          "-DPNGLIB_LIBNAME=PNG${PNGLIB_MAJOR}${PNGLIB_MINOR}_0"
+                          "-DPNGLIB_VERSION=${PNGLIB_VERSION}"
+                          "-DSYMBOL_PREFIX=${SYMBOL_PREFIX}"
+                          "-DPNG_NO_USE_READ_MACROS"
+                          "-DPNG_BUILDING_SYMBOL_TABLE"
+                          ${PNG_PREFIX_DEF}
+                          "${INPUT}"
+                  OUTPUT_FILE "${OUTPUT}.tf1"
+                  WORKING_DIRECTORY "${BINDIR}"
+                  RESULT_VARIABLE CPP_FAIL)
+  if(CPP_FAIL)
+    message(FATAL_ERROR "Failed to generate ${OUTPUT}.tf1")
+  endif()
+
+  execute_process(COMMAND "${AWK}" -f "${SRCDIR}/scripts/dfn.awk"
+                          "out=${OUTPUT}.tf2" "${OUTPUT}.tf1"
+                  WORKING_DIRECTORY "${BINDIR}"
+                  RESULT_VARIABLE AWK_FAIL)
+  if(AWK_FAIL)
+    message(FATAL_ERROR "Failed to generate ${OUTPUT}.tf2")
+  endif()
+
+  file(REMOVE "${OUTPUT}.tf1")
+  file(RENAME "${OUTPUT}.tf2" "${OUTPUT}")
+else()
+  message(FATAL_ERROR "Unsupported conversion: ${INPUTEXT} to ${OUTPUTEXT}")
+endif()
diff --git a/extern/libpng/scripts/gensrc.cmake.in b/extern/libpng/scripts/gensrc.cmake.in
new file mode 100644
index 0000000000..f28a622662
--- /dev/null
+++ b/extern/libpng/scripts/gensrc.cmake.in
@@ -0,0 +1,138 @@
+# gensrc.cmake.in
+# Generate source files with awk, based upon the automake logic.
+
+# Copyright (C) 2016 Glenn Randers-Pehrson
+# Written by Roger Leigh, 2016
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Variables substituted from CMakeLists.txt
+set(SRCDIR "@CMAKE_CURRENT_SOURCE_DIR@")
+set(BINDIR "@CMAKE_CURRENT_BINARY_DIR@")
+
+set(AWK "@AWK@")
+set(DFA_XTRA "@DFA_XTRA@")
+set(PNG_PREFIX "@PNG_PREFIX@")
+set(PNGLIB_VERSION "@PNGLIB_VERSION@")
+
+if("${OUTPUT}" STREQUAL "scripts/pnglibconf.c")
+  # Generate scripts/pnglibconf.c
+
+  file(REMOVE "${BINDIR}/pnglibconf.tf6" "${BINDIR}/pnglibconf.tf7")
+
+  execute_process(COMMAND "${CMAKE_COMMAND}" -E echo "com ${PNGLIB_VERSION} STANDARD API DEFINITION"
+                  COMMAND "${AWK}" -f "${SRCDIR}/scripts/options.awk"
+                          "out=pnglibconf.tf6" "logunsupported=1" "version=search"
+                          "${SRCDIR}/pngconf.h" "-"
+                          "${SRCDIR}/scripts/pnglibconf.dfa"
+                  WORKING_DIRECTORY "${BINDIR}"
+                  RESULT_VARIABLE AWK_FAIL)
+  if(AWK_FAIL)
+    message(FATAL_ERROR "Failed to generate pnglibconf.tf6")
+  endif()
+
+  execute_process(COMMAND "${AWK}" -f "${SRCDIR}/scripts/options.awk"
+                  "out=pnglibconf.tf7" "pnglibconf.tf6"
+                  WORKING_DIRECTORY "${BINDIR}"
+                  RESULT_VARIABLE AWK_FAIL)
+  if(AWK_FAIL)
+    message(FATAL_ERROR "Failed to generate pnglibconf.tf7")
+  endif()
+
+  file(REMOVE "pnglibconf.tf6")
+  file(MAKE_DIRECTORY "${BINDIR}/scripts")
+  file(RENAME "pnglibconf.tf7" "${BINDIR}/scripts/pnglibconf.c")
+
+elseif ("${OUTPUT}" STREQUAL "pnglibconf.c")
+  # Generate pnglibconf.c
+
+  file(REMOVE "${BINDIR}/pnglibconf.tf4" "${BINDIR}/pnglibconf.tf5")
+
+  execute_process(COMMAND "${AWK}" -f "${SRCDIR}/scripts/options.awk"
+                  out=pnglibconf.tf4 version=search
+                  ${SRCDIR}/pngconf.h ${SRCDIR}/scripts/pnglibconf.dfa
+                  ${SRCDIR}/pngusr.dfa ${DFA_XTRA}
+                  WORKING_DIRECTORY "${BINDIR}"
+                  RESULT_VARIABLE AWK_FAIL)
+  if(AWK_FAIL)
+    message(FATAL_ERROR "Failed to generate pnglibconf.tf4")
+  endif()
+
+  execute_process(COMMAND "${AWK}" -f "${SRCDIR}/scripts/options.awk"
+                  out=pnglibconf.tf5 pnglibconf.tf4
+                  WORKING_DIRECTORY "${BINDIR}"
+                  RESULT_VARIABLE AWK_FAIL)
+  if(AWK_FAIL)
+    message(FATAL_ERROR "Failed to generate pnglibconf.tf5")
+  endif()
+
+  file(REMOVE "pnglibconf.tf4")
+  file(MAKE_DIRECTORY "${BINDIR}/scripts")
+  file(RENAME "pnglibconf.tf5" "${BINDIR}/pnglibconf.c")
+
+elseif ("${OUTPUT}" STREQUAL "pnglibconf.h")
+  # Generate pnglibconf.h
+
+  file(REMOVE "${BINDIR}/${OUTPUT}")
+  if(PNG_PREFIX)
+    file(REMOVE "pnglibconf.tf8")
+
+    execute_process(COMMAND "${AWK}" "s==0 && NR>1{print prev}
+                             s==0{prev=\$0}
+                             s==1{print \"#define\", \$1, \"${PNG_PREFIX}\" \$1}
+                             s==2{print \"#define ${PNG_PREFIX}png_\" \$1, \"PNG_\" \$1}
+                             END{print prev}" s=0 pnglibconf.out s=1 "${BINDIR}/scripts/prefix.out"
+                             s=2 "${SRCDIR}/scripts/macro.lst"
+                    OUTPUT_FILE pnglibconf.tf8
+                    RESULT_VARIABLE AWK_FAIL)
+    if(AWK_FAIL)
+      message(FATAL_ERROR "Failed to generate pnglibconf.tf8")
+    endif()
+
+    file(RENAME "pnglibconf.tf8" "${BINDIR}/${OUTPUT}")
+  else()
+    execute_process(COMMAND "${CMAKE_COMMAND}" -E copy "${BINDIR}/pnglibconf.out"
+                                                       "${BINDIR}/${OUTPUT}"
+                    RESULT_VARIABLE COPY_FAIL)
+    if(COPY_FAIL)
+      message(FATAL_ERROR "Failed to create pnglibconf.h")
+    endif()
+  endif()
+
+elseif ("${OUTPUT}" STREQUAL "pngprefix.h")
+  # Generate pngprefix.h
+
+  file(REMOVE "${BINDIR}/${OUTPUT}")
+
+  if(PNG_PREFIX)
+    file(REMOVE "pngprefix.tf1")
+
+    execute_process(COMMAND "${AWK}"
+                            "{print \"#define\", \$1, \"${PNG_PREFIX}\" \$1}"
+                            "${BINDIR}/scripts/intprefix.out"
+                    OUTPUT_FILE "pngprefix.tf1"
+                    RESULT_VARIABLE AWK_FAIL)
+    if(AWK_FAIL)
+      message(FATAL_ERROR "Failed to generate pngprefix.tf1")
+    endif()
+
+    file(RENAME "pngprefix.tf1" "${BINDIR}/${OUTPUT}")
+  else()
+    file(WRITE "${BINDIR}/${OUTPUT}" "/* No libpng symbol prefix configured. */")
+  endif()
+
+elseif("${OUTPUT}" STREQUAL "scripts/pnglibconf.h.prebuilt")
+  # Generate scripts/pnglibconf.h.prebuilt (fails build)
+
+  message(STATUS "Attempting to build scripts/pnglibconf.h.prebuilt")
+  message(STATUS "This is a machine generated file, but if you want to make")
+  message(STATUS "a new one simply build the 'genfiles' target, and copy")
+  message(STATUS "scripts/pnglibconf.out to scripts/pnglibconf.h.prebuilt")
+  message(STATUS "AND set PNG_ZLIB_VERNUM to 0 (you MUST do this)")
+  message(FATAL_ERROR "Stopping build")
+
+else()
+  message(FATAL_ERROR "Unsupported output: ${OUTPUT}")
+endif()
diff --git a/extern/libpng/scripts/intprefix.c b/extern/libpng/scripts/intprefix.c
new file mode 100644
index 0000000000..254f8e94b4
--- /dev/null
+++ b/extern/libpng/scripts/intprefix.c
@@ -0,0 +1,22 @@
+
+/* intprefix.c - generate an unprefixed internal symbol list
+ *
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2013-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_INTERNAL_DATA(type, name, array)\
+        PNG_DFN "@" name "@"
+
+#define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
+        PNG_DFN "@" name "@"
+
+#define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
+        PNG_DFN "@" name "@"
+
+#define PNGPREFIX_H /* self generation */
+#include "../pngpriv.h"
diff --git a/extern/libpng/scripts/libpng-config-body.in b/extern/libpng/scripts/libpng-config-body.in
new file mode 100644
index 0000000000..b466432d54
--- /dev/null
+++ b/extern/libpng/scripts/libpng-config-body.in
@@ -0,0 +1,96 @@
+
+usage()
+{
+    cat <<EOF
+Usage: libpng-config [OPTION] ...
+
+Known values for OPTION are:
+
+  --prefix        print libpng prefix
+  --libdir        print path to directory containing library
+  --libs          print library linking information
+  --ccopts        print compiler options
+  --cppflags      print pre-processor flags
+  --cflags        print preprocessor flags, I_opts, and compiler options
+  --I_opts        print "-I" include options
+  --L_opts        print linker "-L" flags for dynamic linking
+  --R_opts        print dynamic linker "-R" or "-rpath" flags
+  --ldopts        print linker options
+  --ldflags       print linker flags (ldopts, L_opts, R_opts, and libs)
+  --static        revise subsequent outputs for static linking
+  --help          print this help and exit
+  --version       print version information
+EOF
+
+    exit $1
+}
+
+if test $# -eq 0; then
+    usage 1
+fi
+
+while test $# -gt 0; do
+    case "$1" in
+
+    --prefix)
+        echo ${prefix}
+        ;;
+
+    --version)
+        echo ${version}
+        exit 0
+        ;;
+
+    --help)
+        usage 0
+        ;;
+
+    --ccopts)
+        echo ${ccopts}
+        ;;
+
+    --cppflags)
+        echo ${cppflags}
+        ;;
+
+    --cflags)
+        echo ${I_opts} ${cppflags} ${ccopts}
+        ;;
+
+    --libdir)
+        echo ${libdir}
+        ;;
+
+    --libs)
+        echo ${libs}
+        ;;
+
+    --I_opts)
+        echo ${I_opts}
+        ;;
+
+    --L_opts)
+        echo ${L_opts}
+        ;;
+
+    --R_opts)
+        echo ${R_opts}
+        ;;
+
+    --ldflags)
+        echo ${ldflags} ${L_opts} ${R_opts} ${libs}
+        ;;
+
+    --static)
+        R_opts=""
+        ;;
+
+    *)
+        usage
+        exit 1
+        ;;
+    esac
+    shift
+done
+
+exit 0
diff --git a/extern/libpng/scripts/libpng-config-head.in b/extern/libpng/scripts/libpng-config-head.in
new file mode 100644
index 0000000000..2a5afb46a2
--- /dev/null
+++ b/extern/libpng/scripts/libpng-config-head.in
@@ -0,0 +1,24 @@
+#! /bin/sh
+
+# libpng-config
+# provides configuration info for libpng.
+
+# Copyright (C) 2002 Glenn Randers-Pehrson
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Modeled after libxml-config.
+
+version=1.6.37
+prefix=""
+libdir=""
+libs=""
+I_opts=""
+L_opts=""
+R_opts=""
+cppflags=""
+ccopts=""
+ldopts=""
+
diff --git a/extern/libpng/scripts/libpng.pc.in b/extern/libpng/scripts/libpng.pc.in
new file mode 100644
index 0000000000..416fefe86e
--- /dev/null
+++ b/extern/libpng/scripts/libpng.pc.in
@@ -0,0 +1,10 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@/libpng16
+
+Name: libpng
+Description: Loads and saves PNG files
+Version: 1.6.37
+Libs: -L${libdir} -lpng16
+Cflags: -I${includedir}
diff --git a/extern/libpng/scripts/libtool.m4 b/extern/libpng/scripts/libtool.m4
new file mode 100644
index 0000000000..a3bc337b79
--- /dev/null
+++ b/extern/libpng/scripts/libtool.m4
@@ -0,0 +1,8369 @@
+# libtool.m4 - Configure libtool for the host system. -*-Autoconf-*-
+#
+#   Copyright (C) 1996-2001, 2003-2015 Free Software Foundation, Inc.
+#   Written by Gordon Matzigkeit, 1996
+#
+# This file is free software; the Free Software Foundation gives
+# unlimited permission to copy and/or distribute it, with or without
+# modifications, as long as this notice is preserved.
+
+m4_define([_LT_COPYING], [dnl
+# Copyright (C) 2014 Free Software Foundation, Inc.
+# This is free software; see the source for copying conditions.  There is NO
+# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+# GNU Libtool is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of of the License, or
+# (at your option) any later version.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program or library that is built
+# using GNU Libtool, you may include this file under the  same
+# distribution terms that you use for the rest of that program.
+#
+# GNU Libtool is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+])
+
+# serial 58 LT_INIT
+
+
+# LT_PREREQ(VERSION)
+# ------------------
+# Complain and exit if this libtool version is less that VERSION.
+m4_defun([LT_PREREQ],
+[m4_if(m4_version_compare(m4_defn([LT_PACKAGE_VERSION]), [$1]), -1,
+       [m4_default([$3],
+		   [m4_fatal([Libtool version $1 or higher is required],
+		             63)])],
+       [$2])])
+
+
+# _LT_CHECK_BUILDDIR
+# ------------------
+# Complain if the absolute build directory name contains unusual characters
+m4_defun([_LT_CHECK_BUILDDIR],
+[case `pwd` in
+  *\ * | *\	*)
+    AC_MSG_WARN([Libtool does not cope well with whitespace in `pwd`]) ;;
+esac
+])
+
+
+# LT_INIT([OPTIONS])
+# ------------------
+AC_DEFUN([LT_INIT],
+[AC_PREREQ([2.62])dnl We use AC_PATH_PROGS_FEATURE_CHECK
+AC_REQUIRE([AC_CONFIG_AUX_DIR_DEFAULT])dnl
+AC_BEFORE([$0], [LT_LANG])dnl
+AC_BEFORE([$0], [LT_OUTPUT])dnl
+AC_BEFORE([$0], [LTDL_INIT])dnl
+m4_require([_LT_CHECK_BUILDDIR])dnl
+
+dnl Autoconf doesn't catch unexpanded LT_ macros by default:
+m4_pattern_forbid([^_?LT_[A-Z_]+$])dnl
+m4_pattern_allow([^(_LT_EOF|LT_DLGLOBAL|LT_DLLAZY_OR_NOW|LT_MULTI_MODULE)$])dnl
+dnl aclocal doesn't pull ltoptions.m4, ltsugar.m4, or ltversion.m4
+dnl unless we require an AC_DEFUNed macro:
+AC_REQUIRE([LTOPTIONS_VERSION])dnl
+AC_REQUIRE([LTSUGAR_VERSION])dnl
+AC_REQUIRE([LTVERSION_VERSION])dnl
+AC_REQUIRE([LTOBSOLETE_VERSION])dnl
+m4_require([_LT_PROG_LTMAIN])dnl
+
+_LT_SHELL_INIT([SHELL=${CONFIG_SHELL-/bin/sh}])
+
+dnl Parse OPTIONS
+_LT_SET_OPTIONS([$0], [$1])
+
+# This can be used to rebuild libtool when needed
+LIBTOOL_DEPS=$ltmain
+
+# Always use our own libtool.
+LIBTOOL='$(SHELL) $(top_builddir)/libtool'
+AC_SUBST(LIBTOOL)dnl
+
+_LT_SETUP
+
+# Only expand once:
+m4_define([LT_INIT])
+])# LT_INIT
+
+# Old names:
+AU_ALIAS([AC_PROG_LIBTOOL], [LT_INIT])
+AU_ALIAS([AM_PROG_LIBTOOL], [LT_INIT])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_PROG_LIBTOOL], [])
+dnl AC_DEFUN([AM_PROG_LIBTOOL], [])
+
+
+# _LT_PREPARE_CC_BASENAME
+# -----------------------
+m4_defun([_LT_PREPARE_CC_BASENAME], [
+# Calculate cc_basename.  Skip known compiler wrappers and cross-prefix.
+func_cc_basename ()
+{
+    for cc_temp in @S|@*""; do
+      case $cc_temp in
+        compile | *[[\\/]]compile | ccache | *[[\\/]]ccache ) ;;
+        distcc | *[[\\/]]distcc | purify | *[[\\/]]purify ) ;;
+        \-*) ;;
+        *) break;;
+      esac
+    done
+    func_cc_basename_result=`$ECHO "$cc_temp" | $SED "s%.*/%%; s%^$host_alias-%%"`
+}
+])# _LT_PREPARE_CC_BASENAME
+
+
+# _LT_CC_BASENAME(CC)
+# -------------------
+# It would be clearer to call AC_REQUIREs from _LT_PREPARE_CC_BASENAME,
+# but that macro is also expanded into generated libtool script, which
+# arranges for $SED and $ECHO to be set by different means.
+m4_defun([_LT_CC_BASENAME],
+[m4_require([_LT_PREPARE_CC_BASENAME])dnl
+AC_REQUIRE([_LT_DECL_SED])dnl
+AC_REQUIRE([_LT_PROG_ECHO_BACKSLASH])dnl
+func_cc_basename $1
+cc_basename=$func_cc_basename_result
+])
+
+
+# _LT_FILEUTILS_DEFAULTS
+# ----------------------
+# It is okay to use these file commands and assume they have been set
+# sensibly after 'm4_require([_LT_FILEUTILS_DEFAULTS])'.
+m4_defun([_LT_FILEUTILS_DEFAULTS],
+[: ${CP="cp -f"}
+: ${MV="mv -f"}
+: ${RM="rm -f"}
+])# _LT_FILEUTILS_DEFAULTS
+
+
+# _LT_SETUP
+# ---------
+m4_defun([_LT_SETUP],
+[AC_REQUIRE([AC_CANONICAL_HOST])dnl
+AC_REQUIRE([AC_CANONICAL_BUILD])dnl
+AC_REQUIRE([_LT_PREPARE_SED_QUOTE_VARS])dnl
+AC_REQUIRE([_LT_PROG_ECHO_BACKSLASH])dnl
+
+_LT_DECL([], [PATH_SEPARATOR], [1], [The PATH separator for the build system])dnl
+dnl
+_LT_DECL([], [host_alias], [0], [The host system])dnl
+_LT_DECL([], [host], [0])dnl
+_LT_DECL([], [host_os], [0])dnl
+dnl
+_LT_DECL([], [build_alias], [0], [The build system])dnl
+_LT_DECL([], [build], [0])dnl
+_LT_DECL([], [build_os], [0])dnl
+dnl
+AC_REQUIRE([AC_PROG_CC])dnl
+AC_REQUIRE([LT_PATH_LD])dnl
+AC_REQUIRE([LT_PATH_NM])dnl
+dnl
+AC_REQUIRE([AC_PROG_LN_S])dnl
+test -z "$LN_S" && LN_S="ln -s"
+_LT_DECL([], [LN_S], [1], [Whether we need soft or hard links])dnl
+dnl
+AC_REQUIRE([LT_CMD_MAX_LEN])dnl
+_LT_DECL([objext], [ac_objext], [0], [Object file suffix (normally "o")])dnl
+_LT_DECL([], [exeext], [0], [Executable file suffix (normally "")])dnl
+dnl
+m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+m4_require([_LT_CHECK_SHELL_FEATURES])dnl
+m4_require([_LT_PATH_CONVERSION_FUNCTIONS])dnl
+m4_require([_LT_CMD_RELOAD])dnl
+m4_require([_LT_CHECK_MAGIC_METHOD])dnl
+m4_require([_LT_CHECK_SHAREDLIB_FROM_LINKLIB])dnl
+m4_require([_LT_CMD_OLD_ARCHIVE])dnl
+m4_require([_LT_CMD_GLOBAL_SYMBOLS])dnl
+m4_require([_LT_WITH_SYSROOT])dnl
+m4_require([_LT_CMD_TRUNCATE])dnl
+
+_LT_CONFIG_LIBTOOL_INIT([
+# See if we are running on zsh, and set the options that allow our
+# commands through without removal of \ escapes INIT.
+if test -n "\${ZSH_VERSION+set}"; then
+   setopt NO_GLOB_SUBST
+fi
+])
+if test -n "${ZSH_VERSION+set}"; then
+   setopt NO_GLOB_SUBST
+fi
+
+_LT_CHECK_OBJDIR
+
+m4_require([_LT_TAG_COMPILER])dnl
+
+case $host_os in
+aix3*)
+  # AIX sometimes has problems with the GCC collect2 program.  For some
+  # reason, if we set the COLLECT_NAMES environment variable, the problems
+  # vanish in a puff of smoke.
+  if test set != "${COLLECT_NAMES+set}"; then
+    COLLECT_NAMES=
+    export COLLECT_NAMES
+  fi
+  ;;
+esac
+
+# Global variables:
+ofile=libtool
+can_build_shared=yes
+
+# All known linkers require a '.a' archive for static linking (except MSVC,
+# which needs '.lib').
+libext=a
+
+with_gnu_ld=$lt_cv_prog_gnu_ld
+
+old_CC=$CC
+old_CFLAGS=$CFLAGS
+
+# Set sane defaults for various variables
+test -z "$CC" && CC=cc
+test -z "$LTCC" && LTCC=$CC
+test -z "$LTCFLAGS" && LTCFLAGS=$CFLAGS
+test -z "$LD" && LD=ld
+test -z "$ac_objext" && ac_objext=o
+
+_LT_CC_BASENAME([$compiler])
+
+# Only perform the check for file, if the check method requires it
+test -z "$MAGIC_CMD" && MAGIC_CMD=file
+case $deplibs_check_method in
+file_magic*)
+  if test "$file_magic_cmd" = '$MAGIC_CMD'; then
+    _LT_PATH_MAGIC
+  fi
+  ;;
+esac
+
+# Use C for the default configuration in the libtool script
+LT_SUPPORTED_TAG([CC])
+_LT_LANG_C_CONFIG
+_LT_LANG_DEFAULT_CONFIG
+_LT_CONFIG_COMMANDS
+])# _LT_SETUP
+
+
+# _LT_PREPARE_SED_QUOTE_VARS
+# --------------------------
+# Define a few sed substitution that help us do robust quoting.
+m4_defun([_LT_PREPARE_SED_QUOTE_VARS],
+[# Backslashify metacharacters that are still active within
+# double-quoted strings.
+sed_quote_subst='s/\([["`$\\]]\)/\\\1/g'
+
+# Same as above, but do not quote variable references.
+double_quote_subst='s/\([["`\\]]\)/\\\1/g'
+
+# Sed substitution to delay expansion of an escaped shell variable in a
+# double_quote_subst'ed string.
+delay_variable_subst='s/\\\\\\\\\\\$/\\\\\\$/g'
+
+# Sed substitution to delay expansion of an escaped single quote.
+delay_single_quote_subst='s/'\''/'\'\\\\\\\'\''/g'
+
+# Sed substitution to avoid accidental globbing in evaled expressions
+no_glob_subst='s/\*/\\\*/g'
+])
+
+# _LT_PROG_LTMAIN
+# ---------------
+# Note that this code is called both from 'configure', and 'config.status'
+# now that we use AC_CONFIG_COMMANDS to generate libtool.  Notably,
+# 'config.status' has no value for ac_aux_dir unless we are using Automake,
+# so we pass a copy along to make sure it has a sensible value anyway.
+m4_defun([_LT_PROG_LTMAIN],
+[m4_ifdef([AC_REQUIRE_AUX_FILE], [AC_REQUIRE_AUX_FILE([ltmain.sh])])dnl
+_LT_CONFIG_LIBTOOL_INIT([ac_aux_dir='$ac_aux_dir'])
+ltmain=$ac_aux_dir/ltmain.sh
+])# _LT_PROG_LTMAIN
+
+
+## ------------------------------------- ##
+## Accumulate code for creating libtool. ##
+## ------------------------------------- ##
+
+# So that we can recreate a full libtool script including additional
+# tags, we accumulate the chunks of code to send to AC_CONFIG_COMMANDS
+# in macros and then make a single call at the end using the 'libtool'
+# label.
+
+
+# _LT_CONFIG_LIBTOOL_INIT([INIT-COMMANDS])
+# ----------------------------------------
+# Register INIT-COMMANDS to be passed to AC_CONFIG_COMMANDS later.
+m4_define([_LT_CONFIG_LIBTOOL_INIT],
+[m4_ifval([$1],
+          [m4_append([_LT_OUTPUT_LIBTOOL_INIT],
+                     [$1
+])])])
+
+# Initialize.
+m4_define([_LT_OUTPUT_LIBTOOL_INIT])
+
+
+# _LT_CONFIG_LIBTOOL([COMMANDS])
+# ------------------------------
+# Register COMMANDS to be passed to AC_CONFIG_COMMANDS later.
+m4_define([_LT_CONFIG_LIBTOOL],
+[m4_ifval([$1],
+          [m4_append([_LT_OUTPUT_LIBTOOL_COMMANDS],
+                     [$1
+])])])
+
+# Initialize.
+m4_define([_LT_OUTPUT_LIBTOOL_COMMANDS])
+
+
+# _LT_CONFIG_SAVE_COMMANDS([COMMANDS], [INIT_COMMANDS])
+# -----------------------------------------------------
+m4_defun([_LT_CONFIG_SAVE_COMMANDS],
+[_LT_CONFIG_LIBTOOL([$1])
+_LT_CONFIG_LIBTOOL_INIT([$2])
+])
+
+
+# _LT_FORMAT_COMMENT([COMMENT])
+# -----------------------------
+# Add leading comment marks to the start of each line, and a trailing
+# full-stop to the whole comment if one is not present already.
+m4_define([_LT_FORMAT_COMMENT],
+[m4_ifval([$1], [
+m4_bpatsubst([m4_bpatsubst([$1], [^ *], [# ])],
+              [['`$\]], [\\\&])]m4_bmatch([$1], [[!?.]$], [], [.])
+)])
+
+
+
+## ------------------------ ##
+## FIXME: Eliminate VARNAME ##
+## ------------------------ ##
+
+
+# _LT_DECL([CONFIGNAME], VARNAME, VALUE, [DESCRIPTION], [IS-TAGGED?])
+# -------------------------------------------------------------------
+# CONFIGNAME is the name given to the value in the libtool script.
+# VARNAME is the (base) name used in the configure script.
+# VALUE may be 0, 1 or 2 for a computed quote escaped value based on
+# VARNAME.  Any other value will be used directly.
+m4_define([_LT_DECL],
+[lt_if_append_uniq([lt_decl_varnames], [$2], [, ],
+    [lt_dict_add_subkey([lt_decl_dict], [$2], [libtool_name],
+	[m4_ifval([$1], [$1], [$2])])
+    lt_dict_add_subkey([lt_decl_dict], [$2], [value], [$3])
+    m4_ifval([$4],
+	[lt_dict_add_subkey([lt_decl_dict], [$2], [description], [$4])])
+    lt_dict_add_subkey([lt_decl_dict], [$2],
+	[tagged?], [m4_ifval([$5], [yes], [no])])])
+])
+
+
+# _LT_TAGDECL([CONFIGNAME], VARNAME, VALUE, [DESCRIPTION])
+# --------------------------------------------------------
+m4_define([_LT_TAGDECL], [_LT_DECL([$1], [$2], [$3], [$4], [yes])])
+
+
+# lt_decl_tag_varnames([SEPARATOR], [VARNAME1...])
+# ------------------------------------------------
+m4_define([lt_decl_tag_varnames],
+[_lt_decl_filter([tagged?], [yes], $@)])
+
+
+# _lt_decl_filter(SUBKEY, VALUE, [SEPARATOR], [VARNAME1..])
+# ---------------------------------------------------------
+m4_define([_lt_decl_filter],
+[m4_case([$#],
+  [0], [m4_fatal([$0: too few arguments: $#])],
+  [1], [m4_fatal([$0: too few arguments: $#: $1])],
+  [2], [lt_dict_filter([lt_decl_dict], [$1], [$2], [], lt_decl_varnames)],
+  [3], [lt_dict_filter([lt_decl_dict], [$1], [$2], [$3], lt_decl_varnames)],
+  [lt_dict_filter([lt_decl_dict], $@)])[]dnl
+])
+
+
+# lt_decl_quote_varnames([SEPARATOR], [VARNAME1...])
+# --------------------------------------------------
+m4_define([lt_decl_quote_varnames],
+[_lt_decl_filter([value], [1], $@)])
+
+
+# lt_decl_dquote_varnames([SEPARATOR], [VARNAME1...])
+# ---------------------------------------------------
+m4_define([lt_decl_dquote_varnames],
+[_lt_decl_filter([value], [2], $@)])
+
+
+# lt_decl_varnames_tagged([SEPARATOR], [VARNAME1...])
+# ---------------------------------------------------
+m4_define([lt_decl_varnames_tagged],
+[m4_assert([$# <= 2])dnl
+_$0(m4_quote(m4_default([$1], [[, ]])),
+    m4_ifval([$2], [[$2]], [m4_dquote(lt_decl_tag_varnames)]),
+    m4_split(m4_normalize(m4_quote(_LT_TAGS)), [ ]))])
+m4_define([_lt_decl_varnames_tagged],
+[m4_ifval([$3], [lt_combine([$1], [$2], [_], $3)])])
+
+
+# lt_decl_all_varnames([SEPARATOR], [VARNAME1...])
+# ------------------------------------------------
+m4_define([lt_decl_all_varnames],
+[_$0(m4_quote(m4_default([$1], [[, ]])),
+     m4_if([$2], [],
+	   m4_quote(lt_decl_varnames),
+	m4_quote(m4_shift($@))))[]dnl
+])
+m4_define([_lt_decl_all_varnames],
+[lt_join($@, lt_decl_varnames_tagged([$1],
+			lt_decl_tag_varnames([[, ]], m4_shift($@))))dnl
+])
+
+
+# _LT_CONFIG_STATUS_DECLARE([VARNAME])
+# ------------------------------------
+# Quote a variable value, and forward it to 'config.status' so that its
+# declaration there will have the same value as in 'configure'.  VARNAME
+# must have a single quote delimited value for this to work.
+m4_define([_LT_CONFIG_STATUS_DECLARE],
+[$1='`$ECHO "$][$1" | $SED "$delay_single_quote_subst"`'])
+
+
+# _LT_CONFIG_STATUS_DECLARATIONS
+# ------------------------------
+# We delimit libtool config variables with single quotes, so when
+# we write them to config.status, we have to be sure to quote all
+# embedded single quotes properly.  In configure, this macro expands
+# each variable declared with _LT_DECL (and _LT_TAGDECL) into:
+#
+#    <var>='`$ECHO "$<var>" | $SED "$delay_single_quote_subst"`'
+m4_defun([_LT_CONFIG_STATUS_DECLARATIONS],
+[m4_foreach([_lt_var], m4_quote(lt_decl_all_varnames),
+    [m4_n([_LT_CONFIG_STATUS_DECLARE(_lt_var)])])])
+
+
+# _LT_LIBTOOL_TAGS
+# ----------------
+# Output comment and list of tags supported by the script
+m4_defun([_LT_LIBTOOL_TAGS],
+[_LT_FORMAT_COMMENT([The names of the tagged configurations supported by this script])dnl
+available_tags='_LT_TAGS'dnl
+])
+
+
+# _LT_LIBTOOL_DECLARE(VARNAME, [TAG])
+# -----------------------------------
+# Extract the dictionary values for VARNAME (optionally with TAG) and
+# expand to a commented shell variable setting:
+#
+#    # Some comment about what VAR is for.
+#    visible_name=$lt_internal_name
+m4_define([_LT_LIBTOOL_DECLARE],
+[_LT_FORMAT_COMMENT(m4_quote(lt_dict_fetch([lt_decl_dict], [$1],
+					   [description])))[]dnl
+m4_pushdef([_libtool_name],
+    m4_quote(lt_dict_fetch([lt_decl_dict], [$1], [libtool_name])))[]dnl
+m4_case(m4_quote(lt_dict_fetch([lt_decl_dict], [$1], [value])),
+    [0], [_libtool_name=[$]$1],
+    [1], [_libtool_name=$lt_[]$1],
+    [2], [_libtool_name=$lt_[]$1],
+    [_libtool_name=lt_dict_fetch([lt_decl_dict], [$1], [value])])[]dnl
+m4_ifval([$2], [_$2])[]m4_popdef([_libtool_name])[]dnl
+])
+
+
+# _LT_LIBTOOL_CONFIG_VARS
+# -----------------------
+# Produce commented declarations of non-tagged libtool config variables
+# suitable for insertion in the LIBTOOL CONFIG section of the 'libtool'
+# script.  Tagged libtool config variables (even for the LIBTOOL CONFIG
+# section) are produced by _LT_LIBTOOL_TAG_VARS.
+m4_defun([_LT_LIBTOOL_CONFIG_VARS],
+[m4_foreach([_lt_var],
+    m4_quote(_lt_decl_filter([tagged?], [no], [], lt_decl_varnames)),
+    [m4_n([_LT_LIBTOOL_DECLARE(_lt_var)])])])
+
+
+# _LT_LIBTOOL_TAG_VARS(TAG)
+# -------------------------
+m4_define([_LT_LIBTOOL_TAG_VARS],
+[m4_foreach([_lt_var], m4_quote(lt_decl_tag_varnames),
+    [m4_n([_LT_LIBTOOL_DECLARE(_lt_var, [$1])])])])
+
+
+# _LT_TAGVAR(VARNAME, [TAGNAME])
+# ------------------------------
+m4_define([_LT_TAGVAR], [m4_ifval([$2], [$1_$2], [$1])])
+
+
+# _LT_CONFIG_COMMANDS
+# -------------------
+# Send accumulated output to $CONFIG_STATUS.  Thanks to the lists of
+# variables for single and double quote escaping we saved from calls
+# to _LT_DECL, we can put quote escaped variables declarations
+# into 'config.status', and then the shell code to quote escape them in
+# for loops in 'config.status'.  Finally, any additional code accumulated
+# from calls to _LT_CONFIG_LIBTOOL_INIT is expanded.
+m4_defun([_LT_CONFIG_COMMANDS],
+[AC_PROVIDE_IFELSE([LT_OUTPUT],
+	dnl If the libtool generation code has been placed in $CONFIG_LT,
+	dnl instead of duplicating it all over again into config.status,
+	dnl then we will have config.status run $CONFIG_LT later, so it
+	dnl needs to know what name is stored there:
+        [AC_CONFIG_COMMANDS([libtool],
+            [$SHELL $CONFIG_LT || AS_EXIT(1)], [CONFIG_LT='$CONFIG_LT'])],
+    dnl If the libtool generation code is destined for config.status,
+    dnl expand the accumulated commands and init code now:
+    [AC_CONFIG_COMMANDS([libtool],
+        [_LT_OUTPUT_LIBTOOL_COMMANDS], [_LT_OUTPUT_LIBTOOL_COMMANDS_INIT])])
+])#_LT_CONFIG_COMMANDS
+
+
+# Initialize.
+m4_define([_LT_OUTPUT_LIBTOOL_COMMANDS_INIT],
+[
+
+# The HP-UX ksh and POSIX shell print the target directory to stdout
+# if CDPATH is set.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+sed_quote_subst='$sed_quote_subst'
+double_quote_subst='$double_quote_subst'
+delay_variable_subst='$delay_variable_subst'
+_LT_CONFIG_STATUS_DECLARATIONS
+LTCC='$LTCC'
+LTCFLAGS='$LTCFLAGS'
+compiler='$compiler_DEFAULT'
+
+# A function that is used when there is no print builtin or printf.
+func_fallback_echo ()
+{
+  eval 'cat <<_LTECHO_EOF
+\$[]1
+_LTECHO_EOF'
+}
+
+# Quote evaled strings.
+for var in lt_decl_all_varnames([[ \
+]], lt_decl_quote_varnames); do
+    case \`eval \\\\\$ECHO \\\\""\\\\\$\$var"\\\\"\` in
+    *[[\\\\\\\`\\"\\\$]]*)
+      eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"\\\$\$var\\" | \\\$SED \\"\\\$sed_quote_subst\\"\\\`\\\\\\"" ## exclude from sc_prohibit_nested_quotes
+      ;;
+    *)
+      eval "lt_\$var=\\\\\\"\\\$\$var\\\\\\""
+      ;;
+    esac
+done
+
+# Double-quote double-evaled strings.
+for var in lt_decl_all_varnames([[ \
+]], lt_decl_dquote_varnames); do
+    case \`eval \\\\\$ECHO \\\\""\\\\\$\$var"\\\\"\` in
+    *[[\\\\\\\`\\"\\\$]]*)
+      eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"\\\$\$var\\" | \\\$SED -e \\"\\\$double_quote_subst\\" -e \\"\\\$sed_quote_subst\\" -e \\"\\\$delay_variable_subst\\"\\\`\\\\\\"" ## exclude from sc_prohibit_nested_quotes
+      ;;
+    *)
+      eval "lt_\$var=\\\\\\"\\\$\$var\\\\\\""
+      ;;
+    esac
+done
+
+_LT_OUTPUT_LIBTOOL_INIT
+])
+
+# _LT_GENERATED_FILE_INIT(FILE, [COMMENT])
+# ------------------------------------
+# Generate a child script FILE with all initialization necessary to
+# reuse the environment learned by the parent script, and make the
+# file executable.  If COMMENT is supplied, it is inserted after the
+# '#!' sequence but before initialization text begins.  After this
+# macro, additional text can be appended to FILE to form the body of
+# the child script.  The macro ends with non-zero status if the
+# file could not be fully written (such as if the disk is full).
+m4_ifdef([AS_INIT_GENERATED],
+[m4_defun([_LT_GENERATED_FILE_INIT],[AS_INIT_GENERATED($@)])],
+[m4_defun([_LT_GENERATED_FILE_INIT],
+[m4_require([AS_PREPARE])]dnl
+[m4_pushdef([AS_MESSAGE_LOG_FD])]dnl
+[lt_write_fail=0
+cat >$1 <<_ASEOF || lt_write_fail=1
+#! $SHELL
+# Generated by $as_me.
+$2
+SHELL=\${CONFIG_SHELL-$SHELL}
+export SHELL
+_ASEOF
+cat >>$1 <<\_ASEOF || lt_write_fail=1
+AS_SHELL_SANITIZE
+_AS_PREPARE
+exec AS_MESSAGE_FD>&1
+_ASEOF
+test 0 = "$lt_write_fail" && chmod +x $1[]dnl
+m4_popdef([AS_MESSAGE_LOG_FD])])])# _LT_GENERATED_FILE_INIT
+
+# LT_OUTPUT
+# ---------
+# This macro allows early generation of the libtool script (before
+# AC_OUTPUT is called), incase it is used in configure for compilation
+# tests.
+AC_DEFUN([LT_OUTPUT],
+[: ${CONFIG_LT=./config.lt}
+AC_MSG_NOTICE([creating $CONFIG_LT])
+_LT_GENERATED_FILE_INIT(["$CONFIG_LT"],
+[# Run this file to recreate a libtool stub with the current configuration.])
+
+cat >>"$CONFIG_LT" <<\_LTEOF
+lt_cl_silent=false
+exec AS_MESSAGE_LOG_FD>>config.log
+{
+  echo
+  AS_BOX([Running $as_me.])
+} >&AS_MESSAGE_LOG_FD
+
+lt_cl_help="\
+'$as_me' creates a local libtool stub from the current configuration,
+for use in further configure time tests before the real libtool is
+generated.
+
+Usage: $[0] [[OPTIONS]]
+
+  -h, --help      print this help, then exit
+  -V, --version   print version number, then exit
+  -q, --quiet     do not print progress messages
+  -d, --debug     don't remove temporary files
+
+Report bugs to <bug-libtool@gnu.org>."
+
+lt_cl_version="\
+m4_ifset([AC_PACKAGE_NAME], [AC_PACKAGE_NAME ])config.lt[]dnl
+m4_ifset([AC_PACKAGE_VERSION], [ AC_PACKAGE_VERSION])
+configured by $[0], generated by m4_PACKAGE_STRING.
+
+Copyright (C) 2011 Free Software Foundation, Inc.
+This config.lt script is free software; the Free Software Foundation
+gives unlimited permision to copy, distribute and modify it."
+
+while test 0 != $[#]
+do
+  case $[1] in
+    --version | --v* | -V )
+      echo "$lt_cl_version"; exit 0 ;;
+    --help | --h* | -h )
+      echo "$lt_cl_help"; exit 0 ;;
+    --debug | --d* | -d )
+      debug=: ;;
+    --quiet | --q* | --silent | --s* | -q )
+      lt_cl_silent=: ;;
+
+    -*) AC_MSG_ERROR([unrecognized option: $[1]
+Try '$[0] --help' for more information.]) ;;
+
+    *) AC_MSG_ERROR([unrecognized argument: $[1]
+Try '$[0] --help' for more information.]) ;;
+  esac
+  shift
+done
+
+if $lt_cl_silent; then
+  exec AS_MESSAGE_FD>/dev/null
+fi
+_LTEOF
+
+cat >>"$CONFIG_LT" <<_LTEOF
+_LT_OUTPUT_LIBTOOL_COMMANDS_INIT
+_LTEOF
+
+cat >>"$CONFIG_LT" <<\_LTEOF
+AC_MSG_NOTICE([creating $ofile])
+_LT_OUTPUT_LIBTOOL_COMMANDS
+AS_EXIT(0)
+_LTEOF
+chmod +x "$CONFIG_LT"
+
+# configure is writing to config.log, but config.lt does its own redirection,
+# appending to config.log, which fails on DOS, as config.log is still kept
+# open by configure.  Here we exec the FD to /dev/null, effectively closing
+# config.log, so it can be properly (re)opened and appended to by config.lt.
+lt_cl_success=:
+test yes = "$silent" &&
+  lt_config_lt_args="$lt_config_lt_args --quiet"
+exec AS_MESSAGE_LOG_FD>/dev/null
+$SHELL "$CONFIG_LT" $lt_config_lt_args || lt_cl_success=false
+exec AS_MESSAGE_LOG_FD>>config.log
+$lt_cl_success || AS_EXIT(1)
+])# LT_OUTPUT
+
+
+# _LT_CONFIG(TAG)
+# ---------------
+# If TAG is the built-in tag, create an initial libtool script with a
+# default configuration from the untagged config vars.  Otherwise add code
+# to config.status for appending the configuration named by TAG from the
+# matching tagged config vars.
+m4_defun([_LT_CONFIG],
+[m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+_LT_CONFIG_SAVE_COMMANDS([
+  m4_define([_LT_TAG], m4_if([$1], [], [C], [$1]))dnl
+  m4_if(_LT_TAG, [C], [
+    # See if we are running on zsh, and set the options that allow our
+    # commands through without removal of \ escapes.
+    if test -n "${ZSH_VERSION+set}"; then
+      setopt NO_GLOB_SUBST
+    fi
+
+    cfgfile=${ofile}T
+    trap "$RM \"$cfgfile\"; exit 1" 1 2 15
+    $RM "$cfgfile"
+
+    cat <<_LT_EOF >> "$cfgfile"
+#! $SHELL
+# Generated automatically by $as_me ($PACKAGE) $VERSION
+# Libtool was configured on host `(hostname || uname -n) 2>/dev/null | sed 1q`:
+# NOTE: Changes made to this file will be lost: look at ltmain.sh.
+
+# Provide generalized library-building support services.
+# Written by Gordon Matzigkeit, 1996
+
+_LT_COPYING
+_LT_LIBTOOL_TAGS
+
+# Configured defaults for sys_lib_dlsearch_path munging.
+: \${LT_SYS_LIBRARY_PATH="$configure_time_lt_sys_library_path"}
+
+# ### BEGIN LIBTOOL CONFIG
+_LT_LIBTOOL_CONFIG_VARS
+_LT_LIBTOOL_TAG_VARS
+# ### END LIBTOOL CONFIG
+
+_LT_EOF
+
+    cat <<'_LT_EOF' >> "$cfgfile"
+
+# ### BEGIN FUNCTIONS SHARED WITH CONFIGURE
+
+_LT_PREPARE_MUNGE_PATH_LIST
+_LT_PREPARE_CC_BASENAME
+
+# ### END FUNCTIONS SHARED WITH CONFIGURE
+
+_LT_EOF
+
+  case $host_os in
+  aix3*)
+    cat <<\_LT_EOF >> "$cfgfile"
+# AIX sometimes has problems with the GCC collect2 program.  For some
+# reason, if we set the COLLECT_NAMES environment variable, the problems
+# vanish in a puff of smoke.
+if test set != "${COLLECT_NAMES+set}"; then
+  COLLECT_NAMES=
+  export COLLECT_NAMES
+fi
+_LT_EOF
+    ;;
+  esac
+
+  _LT_PROG_LTMAIN
+
+  # We use sed instead of cat because bash on DJGPP gets confused if
+  # if finds mixed CR/LF and LF-only lines.  Since sed operates in
+  # text mode, it properly converts lines to CR/LF.  This bash problem
+  # is reportedly fixed, but why not run on old versions too?
+  sed '$q' "$ltmain" >> "$cfgfile" \
+     || (rm -f "$cfgfile"; exit 1)
+
+   mv -f "$cfgfile" "$ofile" ||
+    (rm -f "$ofile" && cp "$cfgfile" "$ofile" && rm -f "$cfgfile")
+  chmod +x "$ofile"
+],
+[cat <<_LT_EOF >> "$ofile"
+
+dnl Unfortunately we have to use $1 here, since _LT_TAG is not expanded
+dnl in a comment (ie after a #).
+# ### BEGIN LIBTOOL TAG CONFIG: $1
+_LT_LIBTOOL_TAG_VARS(_LT_TAG)
+# ### END LIBTOOL TAG CONFIG: $1
+_LT_EOF
+])dnl /m4_if
+],
+[m4_if([$1], [], [
+    PACKAGE='$PACKAGE'
+    VERSION='$VERSION'
+    RM='$RM'
+    ofile='$ofile'], [])
+])dnl /_LT_CONFIG_SAVE_COMMANDS
+])# _LT_CONFIG
+
+
+# LT_SUPPORTED_TAG(TAG)
+# ---------------------
+# Trace this macro to discover what tags are supported by the libtool
+# --tag option, using:
+#    autoconf --trace 'LT_SUPPORTED_TAG:$1'
+AC_DEFUN([LT_SUPPORTED_TAG], [])
+
+
+# C support is built-in for now
+m4_define([_LT_LANG_C_enabled], [])
+m4_define([_LT_TAGS], [])
+
+
+# LT_LANG(LANG)
+# -------------
+# Enable libtool support for the given language if not already enabled.
+AC_DEFUN([LT_LANG],
+[AC_BEFORE([$0], [LT_OUTPUT])dnl
+m4_case([$1],
+  [C],			[_LT_LANG(C)],
+  [C++],		[_LT_LANG(CXX)],
+  [Go],			[_LT_LANG(GO)],
+  [Java],		[_LT_LANG(GCJ)],
+  [Fortran 77],		[_LT_LANG(F77)],
+  [Fortran],		[_LT_LANG(FC)],
+  [Windows Resource],	[_LT_LANG(RC)],
+  [m4_ifdef([_LT_LANG_]$1[_CONFIG],
+    [_LT_LANG($1)],
+    [m4_fatal([$0: unsupported language: "$1"])])])dnl
+])# LT_LANG
+
+
+# _LT_LANG(LANGNAME)
+# ------------------
+m4_defun([_LT_LANG],
+[m4_ifdef([_LT_LANG_]$1[_enabled], [],
+  [LT_SUPPORTED_TAG([$1])dnl
+  m4_append([_LT_TAGS], [$1 ])dnl
+  m4_define([_LT_LANG_]$1[_enabled], [])dnl
+  _LT_LANG_$1_CONFIG($1)])dnl
+])# _LT_LANG
+
+
+m4_ifndef([AC_PROG_GO], [
+############################################################
+# NOTE: This macro has been submitted for inclusion into   #
+#  GNU Autoconf as AC_PROG_GO.  When it is available in    #
+#  a released version of Autoconf we should remove this    #
+#  macro and use it instead.                               #
+############################################################
+m4_defun([AC_PROG_GO],
+[AC_LANG_PUSH(Go)dnl
+AC_ARG_VAR([GOC],     [Go compiler command])dnl
+AC_ARG_VAR([GOFLAGS], [Go compiler flags])dnl
+_AC_ARG_VAR_LDFLAGS()dnl
+AC_CHECK_TOOL(GOC, gccgo)
+if test -z "$GOC"; then
+  if test -n "$ac_tool_prefix"; then
+    AC_CHECK_PROG(GOC, [${ac_tool_prefix}gccgo], [${ac_tool_prefix}gccgo])
+  fi
+fi
+if test -z "$GOC"; then
+  AC_CHECK_PROG(GOC, gccgo, gccgo, false)
+fi
+])#m4_defun
+])#m4_ifndef
+
+
+# _LT_LANG_DEFAULT_CONFIG
+# -----------------------
+m4_defun([_LT_LANG_DEFAULT_CONFIG],
+[AC_PROVIDE_IFELSE([AC_PROG_CXX],
+  [LT_LANG(CXX)],
+  [m4_define([AC_PROG_CXX], defn([AC_PROG_CXX])[LT_LANG(CXX)])])
+
+AC_PROVIDE_IFELSE([AC_PROG_F77],
+  [LT_LANG(F77)],
+  [m4_define([AC_PROG_F77], defn([AC_PROG_F77])[LT_LANG(F77)])])
+
+AC_PROVIDE_IFELSE([AC_PROG_FC],
+  [LT_LANG(FC)],
+  [m4_define([AC_PROG_FC], defn([AC_PROG_FC])[LT_LANG(FC)])])
+
+dnl The call to [A][M_PROG_GCJ] is quoted like that to stop aclocal
+dnl pulling things in needlessly.
+AC_PROVIDE_IFELSE([AC_PROG_GCJ],
+  [LT_LANG(GCJ)],
+  [AC_PROVIDE_IFELSE([A][M_PROG_GCJ],
+    [LT_LANG(GCJ)],
+    [AC_PROVIDE_IFELSE([LT_PROG_GCJ],
+      [LT_LANG(GCJ)],
+      [m4_ifdef([AC_PROG_GCJ],
+	[m4_define([AC_PROG_GCJ], defn([AC_PROG_GCJ])[LT_LANG(GCJ)])])
+       m4_ifdef([A][M_PROG_GCJ],
+	[m4_define([A][M_PROG_GCJ], defn([A][M_PROG_GCJ])[LT_LANG(GCJ)])])
+       m4_ifdef([LT_PROG_GCJ],
+	[m4_define([LT_PROG_GCJ], defn([LT_PROG_GCJ])[LT_LANG(GCJ)])])])])])
+
+AC_PROVIDE_IFELSE([AC_PROG_GO],
+  [LT_LANG(GO)],
+  [m4_define([AC_PROG_GO], defn([AC_PROG_GO])[LT_LANG(GO)])])
+
+AC_PROVIDE_IFELSE([LT_PROG_RC],
+  [LT_LANG(RC)],
+  [m4_define([LT_PROG_RC], defn([LT_PROG_RC])[LT_LANG(RC)])])
+])# _LT_LANG_DEFAULT_CONFIG
+
+# Obsolete macros:
+AU_DEFUN([AC_LIBTOOL_CXX], [LT_LANG(C++)])
+AU_DEFUN([AC_LIBTOOL_F77], [LT_LANG(Fortran 77)])
+AU_DEFUN([AC_LIBTOOL_FC], [LT_LANG(Fortran)])
+AU_DEFUN([AC_LIBTOOL_GCJ], [LT_LANG(Java)])
+AU_DEFUN([AC_LIBTOOL_RC], [LT_LANG(Windows Resource)])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_LIBTOOL_CXX], [])
+dnl AC_DEFUN([AC_LIBTOOL_F77], [])
+dnl AC_DEFUN([AC_LIBTOOL_FC], [])
+dnl AC_DEFUN([AC_LIBTOOL_GCJ], [])
+dnl AC_DEFUN([AC_LIBTOOL_RC], [])
+
+
+# _LT_TAG_COMPILER
+# ----------------
+m4_defun([_LT_TAG_COMPILER],
+[AC_REQUIRE([AC_PROG_CC])dnl
+
+_LT_DECL([LTCC], [CC], [1], [A C compiler])dnl
+_LT_DECL([LTCFLAGS], [CFLAGS], [1], [LTCC compiler flags])dnl
+_LT_TAGDECL([CC], [compiler], [1], [A language specific compiler])dnl
+_LT_TAGDECL([with_gcc], [GCC], [0], [Is the compiler the GNU compiler?])dnl
+
+# If no C compiler was specified, use CC.
+LTCC=${LTCC-"$CC"}
+
+# If no C compiler flags were specified, use CFLAGS.
+LTCFLAGS=${LTCFLAGS-"$CFLAGS"}
+
+# Allow CC to be a program name with arguments.
+compiler=$CC
+])# _LT_TAG_COMPILER
+
+
+# _LT_COMPILER_BOILERPLATE
+# ------------------------
+# Check for compiler boilerplate output or warnings with
+# the simple compiler test code.
+m4_defun([_LT_COMPILER_BOILERPLATE],
+[m4_require([_LT_DECL_SED])dnl
+ac_outfile=conftest.$ac_objext
+echo "$lt_simple_compile_test_code" >conftest.$ac_ext
+eval "$ac_compile" 2>&1 >/dev/null | $SED '/^$/d; /^ *+/d' >conftest.err
+_lt_compiler_boilerplate=`cat conftest.err`
+$RM conftest*
+])# _LT_COMPILER_BOILERPLATE
+
+
+# _LT_LINKER_BOILERPLATE
+# ----------------------
+# Check for linker boilerplate output or warnings with
+# the simple link test code.
+m4_defun([_LT_LINKER_BOILERPLATE],
+[m4_require([_LT_DECL_SED])dnl
+ac_outfile=conftest.$ac_objext
+echo "$lt_simple_link_test_code" >conftest.$ac_ext
+eval "$ac_link" 2>&1 >/dev/null | $SED '/^$/d; /^ *+/d' >conftest.err
+_lt_linker_boilerplate=`cat conftest.err`
+$RM -r conftest*
+])# _LT_LINKER_BOILERPLATE
+
+# _LT_REQUIRED_DARWIN_CHECKS
+# -------------------------
+m4_defun_once([_LT_REQUIRED_DARWIN_CHECKS],[
+  case $host_os in
+    rhapsody* | darwin*)
+    AC_CHECK_TOOL([DSYMUTIL], [dsymutil], [:])
+    AC_CHECK_TOOL([NMEDIT], [nmedit], [:])
+    AC_CHECK_TOOL([LIPO], [lipo], [:])
+    AC_CHECK_TOOL([OTOOL], [otool], [:])
+    AC_CHECK_TOOL([OTOOL64], [otool64], [:])
+    _LT_DECL([], [DSYMUTIL], [1],
+      [Tool to manipulate archived DWARF debug symbol files on Mac OS X])
+    _LT_DECL([], [NMEDIT], [1],
+      [Tool to change global to local symbols on Mac OS X])
+    _LT_DECL([], [LIPO], [1],
+      [Tool to manipulate fat objects and archives on Mac OS X])
+    _LT_DECL([], [OTOOL], [1],
+      [ldd/readelf like tool for Mach-O binaries on Mac OS X])
+    _LT_DECL([], [OTOOL64], [1],
+      [ldd/readelf like tool for 64 bit Mach-O binaries on Mac OS X 10.4])
+
+    AC_CACHE_CHECK([for -single_module linker flag],[lt_cv_apple_cc_single_mod],
+      [lt_cv_apple_cc_single_mod=no
+      if test -z "$LT_MULTI_MODULE"; then
+	# By default we will add the -single_module flag. You can override
+	# by either setting the environment variable LT_MULTI_MODULE
+	# non-empty at configure time, or by adding -multi_module to the
+	# link flags.
+	rm -rf libconftest.dylib*
+	echo "int foo(void){return 1;}" > conftest.c
+	echo "$LTCC $LTCFLAGS $LDFLAGS -o libconftest.dylib \
+-dynamiclib -Wl,-single_module conftest.c" >&AS_MESSAGE_LOG_FD
+	$LTCC $LTCFLAGS $LDFLAGS -o libconftest.dylib \
+	  -dynamiclib -Wl,-single_module conftest.c 2>conftest.err
+        _lt_result=$?
+	# If there is a non-empty error log, and "single_module"
+	# appears in it, assume the flag caused a linker warning
+        if test -s conftest.err && $GREP single_module conftest.err; then
+	  cat conftest.err >&AS_MESSAGE_LOG_FD
+	# Otherwise, if the output was created with a 0 exit code from
+	# the compiler, it worked.
+	elif test -f libconftest.dylib && test 0 = "$_lt_result"; then
+	  lt_cv_apple_cc_single_mod=yes
+	else
+	  cat conftest.err >&AS_MESSAGE_LOG_FD
+	fi
+	rm -rf libconftest.dylib*
+	rm -f conftest.*
+      fi])
+
+    AC_CACHE_CHECK([for -exported_symbols_list linker flag],
+      [lt_cv_ld_exported_symbols_list],
+      [lt_cv_ld_exported_symbols_list=no
+      save_LDFLAGS=$LDFLAGS
+      echo "_main" > conftest.sym
+      LDFLAGS="$LDFLAGS -Wl,-exported_symbols_list,conftest.sym"
+      AC_LINK_IFELSE([AC_LANG_PROGRAM([],[])],
+	[lt_cv_ld_exported_symbols_list=yes],
+	[lt_cv_ld_exported_symbols_list=no])
+	LDFLAGS=$save_LDFLAGS
+    ])
+
+    AC_CACHE_CHECK([for -force_load linker flag],[lt_cv_ld_force_load],
+      [lt_cv_ld_force_load=no
+      cat > conftest.c << _LT_EOF
+int forced_loaded() { return 2;}
+_LT_EOF
+      echo "$LTCC $LTCFLAGS -c -o conftest.o conftest.c" >&AS_MESSAGE_LOG_FD
+      $LTCC $LTCFLAGS -c -o conftest.o conftest.c 2>&AS_MESSAGE_LOG_FD
+      echo "$AR cru libconftest.a conftest.o" >&AS_MESSAGE_LOG_FD
+      $AR cru libconftest.a conftest.o 2>&AS_MESSAGE_LOG_FD
+      echo "$RANLIB libconftest.a" >&AS_MESSAGE_LOG_FD
+      $RANLIB libconftest.a 2>&AS_MESSAGE_LOG_FD
+      cat > conftest.c << _LT_EOF
+int main() { return 0;}
+_LT_EOF
+      echo "$LTCC $LTCFLAGS $LDFLAGS -o conftest conftest.c -Wl,-force_load,./libconftest.a" >&AS_MESSAGE_LOG_FD
+      $LTCC $LTCFLAGS $LDFLAGS -o conftest conftest.c -Wl,-force_load,./libconftest.a 2>conftest.err
+      _lt_result=$?
+      if test -s conftest.err && $GREP force_load conftest.err; then
+	cat conftest.err >&AS_MESSAGE_LOG_FD
+      elif test -f conftest && test 0 = "$_lt_result" && $GREP forced_load conftest >/dev/null 2>&1; then
+	lt_cv_ld_force_load=yes
+      else
+	cat conftest.err >&AS_MESSAGE_LOG_FD
+      fi
+        rm -f conftest.err libconftest.a conftest conftest.c
+        rm -rf conftest.dSYM
+    ])
+    case $host_os in
+    rhapsody* | darwin1.[[012]])
+      _lt_dar_allow_undefined='$wl-undefined ${wl}suppress' ;;
+    darwin1.*)
+      _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
+    darwin*) # darwin 5.x on
+      # if running on 10.5 or later, the deployment target defaults
+      # to the OS version, if on x86, and 10.4, the deployment
+      # target defaults to 10.4. Don't you love it?
+      case ${MACOSX_DEPLOYMENT_TARGET-10.0},$host in
+	10.0,*86*-darwin8*|10.0,*-darwin[[91]]*)
+	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
+	10.[[012]][[,.]]*)
+	  _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
+	10.*)
+	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
+      esac
+    ;;
+  esac
+    if test yes = "$lt_cv_apple_cc_single_mod"; then
+      _lt_dar_single_mod='$single_module'
+    fi
+    if test yes = "$lt_cv_ld_exported_symbols_list"; then
+      _lt_dar_export_syms=' $wl-exported_symbols_list,$output_objdir/$libname-symbols.expsym'
+    else
+      _lt_dar_export_syms='~$NMEDIT -s $output_objdir/$libname-symbols.expsym $lib'
+    fi
+    if test : != "$DSYMUTIL" && test no = "$lt_cv_ld_force_load"; then
+      _lt_dsymutil='~$DSYMUTIL $lib || :'
+    else
+      _lt_dsymutil=
+    fi
+    ;;
+  esac
+])
+
+
+# _LT_DARWIN_LINKER_FEATURES([TAG])
+# ---------------------------------
+# Checks for linker and compiler features on darwin
+m4_defun([_LT_DARWIN_LINKER_FEATURES],
+[
+  m4_require([_LT_REQUIRED_DARWIN_CHECKS])
+  _LT_TAGVAR(archive_cmds_need_lc, $1)=no
+  _LT_TAGVAR(hardcode_direct, $1)=no
+  _LT_TAGVAR(hardcode_automatic, $1)=yes
+  _LT_TAGVAR(hardcode_shlibpath_var, $1)=unsupported
+  if test yes = "$lt_cv_ld_force_load"; then
+    _LT_TAGVAR(whole_archive_flag_spec, $1)='`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience $wl-force_load,$conv\"; done; func_echo_all \"$new_convenience\"`'
+    m4_case([$1], [F77], [_LT_TAGVAR(compiler_needs_object, $1)=yes],
+                  [FC],  [_LT_TAGVAR(compiler_needs_object, $1)=yes])
+  else
+    _LT_TAGVAR(whole_archive_flag_spec, $1)=''
+  fi
+  _LT_TAGVAR(link_all_deplibs, $1)=yes
+  _LT_TAGVAR(allow_undefined_flag, $1)=$_lt_dar_allow_undefined
+  case $cc_basename in
+     ifort*|nagfor*) _lt_dar_can_shared=yes ;;
+     *) _lt_dar_can_shared=$GCC ;;
+  esac
+  if test yes = "$_lt_dar_can_shared"; then
+    output_verbose_link_cmd=func_echo_all
+    _LT_TAGVAR(archive_cmds, $1)="\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring $_lt_dar_single_mod$_lt_dsymutil"
+    _LT_TAGVAR(module_cmds, $1)="\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags$_lt_dsymutil"
+    _LT_TAGVAR(archive_expsym_cmds, $1)="sed 's|^|_|' < \$export_symbols > \$output_objdir/\$libname-symbols.expsym~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring $_lt_dar_single_mod$_lt_dar_export_syms$_lt_dsymutil"
+    _LT_TAGVAR(module_expsym_cmds, $1)="sed -e 's|^|_|' < \$export_symbols > \$output_objdir/\$libname-symbols.expsym~\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags$_lt_dar_export_syms$_lt_dsymutil"
+    m4_if([$1], [CXX],
+[   if test yes != "$lt_cv_apple_cc_single_mod"; then
+      _LT_TAGVAR(archive_cmds, $1)="\$CC -r -keep_private_externs -nostdlib -o \$lib-master.o \$libobjs~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$lib-master.o \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring$_lt_dsymutil"
+      _LT_TAGVAR(archive_expsym_cmds, $1)="sed 's|^|_|' < \$export_symbols > \$output_objdir/\$libname-symbols.expsym~\$CC -r -keep_private_externs -nostdlib -o \$lib-master.o \$libobjs~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$lib-master.o \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring$_lt_dar_export_syms$_lt_dsymutil"
+    fi
+],[])
+  else
+  _LT_TAGVAR(ld_shlibs, $1)=no
+  fi
+])
+
+# _LT_SYS_MODULE_PATH_AIX([TAGNAME])
+# ----------------------------------
+# Links a minimal program and checks the executable
+# for the system default hardcoded library path. In most cases,
+# this is /usr/lib:/lib, but when the MPI compilers are used
+# the location of the communication and MPI libs are included too.
+# If we don't find anything, use the default library path according
+# to the aix ld manual.
+# Store the results from the different compilers for each TAGNAME.
+# Allow to override them for all tags through lt_cv_aix_libpath.
+m4_defun([_LT_SYS_MODULE_PATH_AIX],
+[m4_require([_LT_DECL_SED])dnl
+if test set = "${lt_cv_aix_libpath+set}"; then
+  aix_libpath=$lt_cv_aix_libpath
+else
+  AC_CACHE_VAL([_LT_TAGVAR([lt_cv_aix_libpath_], [$1])],
+  [AC_LINK_IFELSE([AC_LANG_PROGRAM],[
+  lt_aix_libpath_sed='[
+      /Import File Strings/,/^$/ {
+	  /^0/ {
+	      s/^0  *\([^ ]*\) *$/\1/
+	      p
+	  }
+      }]'
+  _LT_TAGVAR([lt_cv_aix_libpath_], [$1])=`dump -H conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  # Check for a 64-bit object if we didn't find anything.
+  if test -z "$_LT_TAGVAR([lt_cv_aix_libpath_], [$1])"; then
+    _LT_TAGVAR([lt_cv_aix_libpath_], [$1])=`dump -HX64 conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  fi],[])
+  if test -z "$_LT_TAGVAR([lt_cv_aix_libpath_], [$1])"; then
+    _LT_TAGVAR([lt_cv_aix_libpath_], [$1])=/usr/lib:/lib
+  fi
+  ])
+  aix_libpath=$_LT_TAGVAR([lt_cv_aix_libpath_], [$1])
+fi
+])# _LT_SYS_MODULE_PATH_AIX
+
+
+# _LT_SHELL_INIT(ARG)
+# -------------------
+m4_define([_LT_SHELL_INIT],
+[m4_divert_text([M4SH-INIT], [$1
+])])# _LT_SHELL_INIT
+
+
+
+# _LT_PROG_ECHO_BACKSLASH
+# -----------------------
+# Find how we can fake an echo command that does not interpret backslash.
+# In particular, with Autoconf 2.60 or later we add some code to the start
+# of the generated configure script that will find a shell with a builtin
+# printf (that we can use as an echo command).
+m4_defun([_LT_PROG_ECHO_BACKSLASH],
+[ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
+ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO
+ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO$ECHO
+
+AC_MSG_CHECKING([how to print strings])
+# Test print first, because it will be a builtin if present.
+if test "X`( print -r -- -n ) 2>/dev/null`" = X-n && \
+   test "X`print -r -- $ECHO 2>/dev/null`" = "X$ECHO"; then
+  ECHO='print -r --'
+elif test "X`printf %s $ECHO 2>/dev/null`" = "X$ECHO"; then
+  ECHO='printf %s\n'
+else
+  # Use this function as a fallback that always works.
+  func_fallback_echo ()
+  {
+    eval 'cat <<_LTECHO_EOF
+$[]1
+_LTECHO_EOF'
+  }
+  ECHO='func_fallback_echo'
+fi
+
+# func_echo_all arg...
+# Invoke $ECHO with all args, space-separated.
+func_echo_all ()
+{
+    $ECHO "$*"
+}
+
+case $ECHO in
+  printf*) AC_MSG_RESULT([printf]) ;;
+  print*) AC_MSG_RESULT([print -r]) ;;
+  *) AC_MSG_RESULT([cat]) ;;
+esac
+
+m4_ifdef([_AS_DETECT_SUGGESTED],
+[_AS_DETECT_SUGGESTED([
+  test -n "${ZSH_VERSION+set}${BASH_VERSION+set}" || (
+    ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
+    ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO
+    ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO$ECHO
+    PATH=/empty FPATH=/empty; export PATH FPATH
+    test "X`printf %s $ECHO`" = "X$ECHO" \
+      || test "X`print -r -- $ECHO`" = "X$ECHO" )])])
+
+_LT_DECL([], [SHELL], [1], [Shell to use when invoking shell scripts])
+_LT_DECL([], [ECHO], [1], [An echo program that protects backslashes])
+])# _LT_PROG_ECHO_BACKSLASH
+
+
+# _LT_WITH_SYSROOT
+# ----------------
+AC_DEFUN([_LT_WITH_SYSROOT],
+[AC_MSG_CHECKING([for sysroot])
+AC_ARG_WITH([sysroot],
+[AS_HELP_STRING([--with-sysroot@<:@=DIR@:>@],
+  [Search for dependent libraries within DIR (or the compiler's sysroot
+   if not specified).])],
+[], [with_sysroot=no])
+
+dnl lt_sysroot will always be passed unquoted.  We quote it here
+dnl in case the user passed a directory name.
+lt_sysroot=
+case $with_sysroot in #(
+ yes)
+   if test yes = "$GCC"; then
+     lt_sysroot=`$CC --print-sysroot 2>/dev/null`
+   fi
+   ;; #(
+ /*)
+   lt_sysroot=`echo "$with_sysroot" | sed -e "$sed_quote_subst"`
+   ;; #(
+ no|'')
+   ;; #(
+ *)
+   AC_MSG_RESULT([$with_sysroot])
+   AC_MSG_ERROR([The sysroot must be an absolute path.])
+   ;;
+esac
+
+ AC_MSG_RESULT([${lt_sysroot:-no}])
+_LT_DECL([], [lt_sysroot], [0], [The root where to search for ]dnl
+[dependent libraries, and where our libraries should be installed.])])
+
+# _LT_ENABLE_LOCK
+# ---------------
+m4_defun([_LT_ENABLE_LOCK],
+[AC_ARG_ENABLE([libtool-lock],
+  [AS_HELP_STRING([--disable-libtool-lock],
+    [avoid locking (might break parallel builds)])])
+test no = "$enable_libtool_lock" || enable_libtool_lock=yes
+
+# Some flags need to be propagated to the compiler or linker for good
+# libtool support.
+case $host in
+ia64-*-hpux*)
+  # Find out what ABI is being produced by ac_compile, and set mode
+  # options accordingly.
+  echo 'int i;' > conftest.$ac_ext
+  if AC_TRY_EVAL(ac_compile); then
+    case `/usr/bin/file conftest.$ac_objext` in
+      *ELF-32*)
+	HPUX_IA64_MODE=32
+	;;
+      *ELF-64*)
+	HPUX_IA64_MODE=64
+	;;
+    esac
+  fi
+  rm -rf conftest*
+  ;;
+*-*-irix6*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.
+  echo '[#]line '$LINENO' "configure"' > conftest.$ac_ext
+  if AC_TRY_EVAL(ac_compile); then
+    if test yes = "$lt_cv_prog_gnu_ld"; then
+      case `/usr/bin/file conftest.$ac_objext` in
+	*32-bit*)
+	  LD="${LD-ld} -melf32bsmip"
+	  ;;
+	*N32*)
+	  LD="${LD-ld} -melf32bmipn32"
+	  ;;
+	*64-bit*)
+	  LD="${LD-ld} -melf64bmip"
+	;;
+      esac
+    else
+      case `/usr/bin/file conftest.$ac_objext` in
+	*32-bit*)
+	  LD="${LD-ld} -32"
+	  ;;
+	*N32*)
+	  LD="${LD-ld} -n32"
+	  ;;
+	*64-bit*)
+	  LD="${LD-ld} -64"
+	  ;;
+      esac
+    fi
+  fi
+  rm -rf conftest*
+  ;;
+
+mips64*-*linux*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.
+  echo '[#]line '$LINENO' "configure"' > conftest.$ac_ext
+  if AC_TRY_EVAL(ac_compile); then
+    emul=elf
+    case `/usr/bin/file conftest.$ac_objext` in
+      *32-bit*)
+	emul="${emul}32"
+	;;
+      *64-bit*)
+	emul="${emul}64"
+	;;
+    esac
+    case `/usr/bin/file conftest.$ac_objext` in
+      *MSB*)
+	emul="${emul}btsmip"
+	;;
+      *LSB*)
+	emul="${emul}ltsmip"
+	;;
+    esac
+    case `/usr/bin/file conftest.$ac_objext` in
+      *N32*)
+	emul="${emul}n32"
+	;;
+    esac
+    LD="${LD-ld} -m $emul"
+  fi
+  rm -rf conftest*
+  ;;
+
+x86_64-*kfreebsd*-gnu|x86_64-*linux*|powerpc*-*linux*| \
+s390*-*linux*|s390*-*tpf*|sparc*-*linux*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.  Note that the listed cases only cover the
+  # situations where additional linker options are needed (such as when
+  # doing 32-bit compilation for a host where ld defaults to 64-bit, or
+  # vice versa); the common cases where no linker options are needed do
+  # not appear in the list.
+  echo 'int i;' > conftest.$ac_ext
+  if AC_TRY_EVAL(ac_compile); then
+    case `/usr/bin/file conftest.o` in
+      *32-bit*)
+	case $host in
+	  x86_64-*kfreebsd*-gnu)
+	    LD="${LD-ld} -m elf_i386_fbsd"
+	    ;;
+	  x86_64-*linux*)
+	    case `/usr/bin/file conftest.o` in
+	      *x86-64*)
+		LD="${LD-ld} -m elf32_x86_64"
+		;;
+	      *)
+		LD="${LD-ld} -m elf_i386"
+		;;
+	    esac
+	    ;;
+	  powerpc64le-*linux*)
+	    LD="${LD-ld} -m elf32lppclinux"
+	    ;;
+	  powerpc64-*linux*)
+	    LD="${LD-ld} -m elf32ppclinux"
+	    ;;
+	  s390x-*linux*)
+	    LD="${LD-ld} -m elf_s390"
+	    ;;
+	  sparc64-*linux*)
+	    LD="${LD-ld} -m elf32_sparc"
+	    ;;
+	esac
+	;;
+      *64-bit*)
+	case $host in
+	  x86_64-*kfreebsd*-gnu)
+	    LD="${LD-ld} -m elf_x86_64_fbsd"
+	    ;;
+	  x86_64-*linux*)
+	    LD="${LD-ld} -m elf_x86_64"
+	    ;;
+	  powerpcle-*linux*)
+	    LD="${LD-ld} -m elf64lppc"
+	    ;;
+	  powerpc-*linux*)
+	    LD="${LD-ld} -m elf64ppc"
+	    ;;
+	  s390*-*linux*|s390*-*tpf*)
+	    LD="${LD-ld} -m elf64_s390"
+	    ;;
+	  sparc*-*linux*)
+	    LD="${LD-ld} -m elf64_sparc"
+	    ;;
+	esac
+	;;
+    esac
+  fi
+  rm -rf conftest*
+  ;;
+
+*-*-sco3.2v5*)
+  # On SCO OpenServer 5, we need -belf to get full-featured binaries.
+  SAVE_CFLAGS=$CFLAGS
+  CFLAGS="$CFLAGS -belf"
+  AC_CACHE_CHECK([whether the C compiler needs -belf], lt_cv_cc_needs_belf,
+    [AC_LANG_PUSH(C)
+     AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],[[]])],[lt_cv_cc_needs_belf=yes],[lt_cv_cc_needs_belf=no])
+     AC_LANG_POP])
+  if test yes != "$lt_cv_cc_needs_belf"; then
+    # this is probably gcc 2.8.0, egcs 1.0 or newer; no need for -belf
+    CFLAGS=$SAVE_CFLAGS
+  fi
+  ;;
+*-*solaris*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.
+  echo 'int i;' > conftest.$ac_ext
+  if AC_TRY_EVAL(ac_compile); then
+    case `/usr/bin/file conftest.o` in
+    *64-bit*)
+      case $lt_cv_prog_gnu_ld in
+      yes*)
+        case $host in
+        i?86-*-solaris*|x86_64-*-solaris*)
+          LD="${LD-ld} -m elf_x86_64"
+          ;;
+        sparc*-*-solaris*)
+          LD="${LD-ld} -m elf64_sparc"
+          ;;
+        esac
+        # GNU ld 2.21 introduced _sol2 emulations.  Use them if available.
+        if ${LD-ld} -V | grep _sol2 >/dev/null 2>&1; then
+          LD=${LD-ld}_sol2
+        fi
+        ;;
+      *)
+	if ${LD-ld} -64 -r -o conftest2.o conftest.o >/dev/null 2>&1; then
+	  LD="${LD-ld} -64"
+	fi
+	;;
+      esac
+      ;;
+    esac
+  fi
+  rm -rf conftest*
+  ;;
+esac
+
+need_locks=$enable_libtool_lock
+])# _LT_ENABLE_LOCK
+
+
+# _LT_PROG_AR
+# -----------
+m4_defun([_LT_PROG_AR],
+[AC_CHECK_TOOLS(AR, [ar], false)
+: ${AR=ar}
+: ${AR_FLAGS=cru}
+_LT_DECL([], [AR], [1], [The archiver])
+_LT_DECL([], [AR_FLAGS], [1], [Flags to create an archive])
+
+AC_CACHE_CHECK([for archiver @FILE support], [lt_cv_ar_at_file],
+  [lt_cv_ar_at_file=no
+   AC_COMPILE_IFELSE([AC_LANG_PROGRAM],
+     [echo conftest.$ac_objext > conftest.lst
+      lt_ar_try='$AR $AR_FLAGS libconftest.a @conftest.lst >&AS_MESSAGE_LOG_FD'
+      AC_TRY_EVAL([lt_ar_try])
+      if test 0 -eq "$ac_status"; then
+	# Ensure the archiver fails upon bogus file names.
+	rm -f conftest.$ac_objext libconftest.a
+	AC_TRY_EVAL([lt_ar_try])
+	if test 0 -ne "$ac_status"; then
+          lt_cv_ar_at_file=@
+        fi
+      fi
+      rm -f conftest.* libconftest.a
+     ])
+  ])
+
+if test no = "$lt_cv_ar_at_file"; then
+  archiver_list_spec=
+else
+  archiver_list_spec=$lt_cv_ar_at_file
+fi
+_LT_DECL([], [archiver_list_spec], [1],
+  [How to feed a file listing to the archiver])
+])# _LT_PROG_AR
+
+
+# _LT_CMD_OLD_ARCHIVE
+# -------------------
+m4_defun([_LT_CMD_OLD_ARCHIVE],
+[_LT_PROG_AR
+
+AC_CHECK_TOOL(STRIP, strip, :)
+test -z "$STRIP" && STRIP=:
+_LT_DECL([], [STRIP], [1], [A symbol stripping program])
+
+AC_CHECK_TOOL(RANLIB, ranlib, :)
+test -z "$RANLIB" && RANLIB=:
+_LT_DECL([], [RANLIB], [1],
+    [Commands used to install an old-style archive])
+
+# Determine commands to create old-style static archives.
+old_archive_cmds='$AR $AR_FLAGS $oldlib$oldobjs'
+old_postinstall_cmds='chmod 644 $oldlib'
+old_postuninstall_cmds=
+
+if test -n "$RANLIB"; then
+  case $host_os in
+  bitrig* | openbsd*)
+    old_postinstall_cmds="$old_postinstall_cmds~\$RANLIB -t \$tool_oldlib"
+    ;;
+  *)
+    old_postinstall_cmds="$old_postinstall_cmds~\$RANLIB \$tool_oldlib"
+    ;;
+  esac
+  old_archive_cmds="$old_archive_cmds~\$RANLIB \$tool_oldlib"
+fi
+
+case $host_os in
+  darwin*)
+    lock_old_archive_extraction=yes ;;
+  *)
+    lock_old_archive_extraction=no ;;
+esac
+_LT_DECL([], [old_postinstall_cmds], [2])
+_LT_DECL([], [old_postuninstall_cmds], [2])
+_LT_TAGDECL([], [old_archive_cmds], [2],
+    [Commands used to build an old-style archive])
+_LT_DECL([], [lock_old_archive_extraction], [0],
+    [Whether to use a lock for old archive extraction])
+])# _LT_CMD_OLD_ARCHIVE
+
+
+# _LT_COMPILER_OPTION(MESSAGE, VARIABLE-NAME, FLAGS,
+#		[OUTPUT-FILE], [ACTION-SUCCESS], [ACTION-FAILURE])
+# ----------------------------------------------------------------
+# Check whether the given compiler option works
+AC_DEFUN([_LT_COMPILER_OPTION],
+[m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+m4_require([_LT_DECL_SED])dnl
+AC_CACHE_CHECK([$1], [$2],
+  [$2=no
+   m4_if([$4], , [ac_outfile=conftest.$ac_objext], [ac_outfile=$4])
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+   lt_compiler_flag="$3"  ## exclude from sc_useless_quotes_in_assignment
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   # The option is referenced via a variable to avoid confusing sed.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [[^ ]]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&AS_MESSAGE_LOG_FD)
+   (eval "$lt_compile" 2>conftest.err)
+   ac_status=$?
+   cat conftest.err >&AS_MESSAGE_LOG_FD
+   echo "$as_me:$LINENO: \$? = $ac_status" >&AS_MESSAGE_LOG_FD
+   if (exit $ac_status) && test -s "$ac_outfile"; then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings other than the usual output.
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' >conftest.exp
+     $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+     if test ! -s conftest.er2 || diff conftest.exp conftest.er2 >/dev/null; then
+       $2=yes
+     fi
+   fi
+   $RM conftest*
+])
+
+if test yes = "[$]$2"; then
+    m4_if([$5], , :, [$5])
+else
+    m4_if([$6], , :, [$6])
+fi
+])# _LT_COMPILER_OPTION
+
+# Old name:
+AU_ALIAS([AC_LIBTOOL_COMPILER_OPTION], [_LT_COMPILER_OPTION])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_LIBTOOL_COMPILER_OPTION], [])
+
+
+# _LT_LINKER_OPTION(MESSAGE, VARIABLE-NAME, FLAGS,
+#                  [ACTION-SUCCESS], [ACTION-FAILURE])
+# ----------------------------------------------------
+# Check whether the given linker option works
+AC_DEFUN([_LT_LINKER_OPTION],
+[m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+m4_require([_LT_DECL_SED])dnl
+AC_CACHE_CHECK([$1], [$2],
+  [$2=no
+   save_LDFLAGS=$LDFLAGS
+   LDFLAGS="$LDFLAGS $3"
+   echo "$lt_simple_link_test_code" > conftest.$ac_ext
+   if (eval $ac_link 2>conftest.err) && test -s conftest$ac_exeext; then
+     # The linker can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     if test -s conftest.err; then
+       # Append any errors to the config.log.
+       cat conftest.err 1>&AS_MESSAGE_LOG_FD
+       $ECHO "$_lt_linker_boilerplate" | $SED '/^$/d' > conftest.exp
+       $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+       if diff conftest.exp conftest.er2 >/dev/null; then
+         $2=yes
+       fi
+     else
+       $2=yes
+     fi
+   fi
+   $RM -r conftest*
+   LDFLAGS=$save_LDFLAGS
+])
+
+if test yes = "[$]$2"; then
+    m4_if([$4], , :, [$4])
+else
+    m4_if([$5], , :, [$5])
+fi
+])# _LT_LINKER_OPTION
+
+# Old name:
+AU_ALIAS([AC_LIBTOOL_LINKER_OPTION], [_LT_LINKER_OPTION])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_LIBTOOL_LINKER_OPTION], [])
+
+
+# LT_CMD_MAX_LEN
+#---------------
+AC_DEFUN([LT_CMD_MAX_LEN],
+[AC_REQUIRE([AC_CANONICAL_HOST])dnl
+# find the maximum length of command line arguments
+AC_MSG_CHECKING([the maximum length of command line arguments])
+AC_CACHE_VAL([lt_cv_sys_max_cmd_len], [dnl
+  i=0
+  teststring=ABCD
+
+  case $build_os in
+  msdosdjgpp*)
+    # On DJGPP, this test can blow up pretty badly due to problems in libc
+    # (any single argument exceeding 2000 bytes causes a buffer overrun
+    # during glob expansion).  Even if it were fixed, the result of this
+    # check would be larger than it should be.
+    lt_cv_sys_max_cmd_len=12288;    # 12K is about right
+    ;;
+
+  gnu*)
+    # Under GNU Hurd, this test is not required because there is
+    # no limit to the length of command line arguments.
+    # Libtool will interpret -1 as no limit whatsoever
+    lt_cv_sys_max_cmd_len=-1;
+    ;;
+
+  cygwin* | mingw* | cegcc*)
+    # On Win9x/ME, this test blows up -- it succeeds, but takes
+    # about 5 minutes as the teststring grows exponentially.
+    # Worse, since 9x/ME are not pre-emptively multitasking,
+    # you end up with a "frozen" computer, even though with patience
+    # the test eventually succeeds (with a max line length of 256k).
+    # Instead, let's just punt: use the minimum linelength reported by
+    # all of the supported platforms: 8192 (on NT/2K/XP).
+    lt_cv_sys_max_cmd_len=8192;
+    ;;
+
+  mint*)
+    # On MiNT this can take a long time and run out of memory.
+    lt_cv_sys_max_cmd_len=8192;
+    ;;
+
+  amigaos*)
+    # On AmigaOS with pdksh, this test takes hours, literally.
+    # So we just punt and use a minimum line length of 8192.
+    lt_cv_sys_max_cmd_len=8192;
+    ;;
+
+  bitrig* | darwin* | dragonfly* | freebsd* | netbsd* | openbsd*)
+    # This has been around since 386BSD, at least.  Likely further.
+    if test -x /sbin/sysctl; then
+      lt_cv_sys_max_cmd_len=`/sbin/sysctl -n kern.argmax`
+    elif test -x /usr/sbin/sysctl; then
+      lt_cv_sys_max_cmd_len=`/usr/sbin/sysctl -n kern.argmax`
+    else
+      lt_cv_sys_max_cmd_len=65536	# usable default for all BSDs
+    fi
+    # And add a safety zone
+    lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \/ 4`
+    lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \* 3`
+    ;;
+
+  interix*)
+    # We know the value 262144 and hardcode it with a safety zone (like BSD)
+    lt_cv_sys_max_cmd_len=196608
+    ;;
+
+  os2*)
+    # The test takes a long time on OS/2.
+    lt_cv_sys_max_cmd_len=8192
+    ;;
+
+  osf*)
+    # Dr. Hans Ekkehard Plesser reports seeing a kernel panic running configure
+    # due to this test when exec_disable_arg_limit is 1 on Tru64. It is not
+    # nice to cause kernel panics so lets avoid the loop below.
+    # First set a reasonable default.
+    lt_cv_sys_max_cmd_len=16384
+    #
+    if test -x /sbin/sysconfig; then
+      case `/sbin/sysconfig -q proc exec_disable_arg_limit` in
+        *1*) lt_cv_sys_max_cmd_len=-1 ;;
+      esac
+    fi
+    ;;
+  sco3.2v5*)
+    lt_cv_sys_max_cmd_len=102400
+    ;;
+  sysv5* | sco5v6* | sysv4.2uw2*)
+    kargmax=`grep ARG_MAX /etc/conf/cf.d/stune 2>/dev/null`
+    if test -n "$kargmax"; then
+      lt_cv_sys_max_cmd_len=`echo $kargmax | sed 's/.*[[	 ]]//'`
+    else
+      lt_cv_sys_max_cmd_len=32768
+    fi
+    ;;
+  *)
+    lt_cv_sys_max_cmd_len=`(getconf ARG_MAX) 2> /dev/null`
+    if test -n "$lt_cv_sys_max_cmd_len" && \
+       test undefined != "$lt_cv_sys_max_cmd_len"; then
+      lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \/ 4`
+      lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \* 3`
+    else
+      # Make teststring a little bigger before we do anything with it.
+      # a 1K string should be a reasonable start.
+      for i in 1 2 3 4 5 6 7 8; do
+        teststring=$teststring$teststring
+      done
+      SHELL=${SHELL-${CONFIG_SHELL-/bin/sh}}
+      # If test is not a shell built-in, we'll probably end up computing a
+      # maximum length that is only half of the actual maximum length, but
+      # we can't tell.
+      while { test X`env echo "$teststring$teststring" 2>/dev/null` \
+	         = "X$teststring$teststring"; } >/dev/null 2>&1 &&
+	      test 17 != "$i" # 1/2 MB should be enough
+      do
+        i=`expr $i + 1`
+        teststring=$teststring$teststring
+      done
+      # Only check the string length outside the loop.
+      lt_cv_sys_max_cmd_len=`expr "X$teststring" : ".*" 2>&1`
+      teststring=
+      # Add a significant safety factor because C++ compilers can tack on
+      # massive amounts of additional arguments before passing them to the
+      # linker.  It appears as though 1/2 is a usable value.
+      lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \/ 2`
+    fi
+    ;;
+  esac
+])
+if test -n "$lt_cv_sys_max_cmd_len"; then
+  AC_MSG_RESULT($lt_cv_sys_max_cmd_len)
+else
+  AC_MSG_RESULT(none)
+fi
+max_cmd_len=$lt_cv_sys_max_cmd_len
+_LT_DECL([], [max_cmd_len], [0],
+    [What is the maximum length of a command?])
+])# LT_CMD_MAX_LEN
+
+# Old name:
+AU_ALIAS([AC_LIBTOOL_SYS_MAX_CMD_LEN], [LT_CMD_MAX_LEN])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_LIBTOOL_SYS_MAX_CMD_LEN], [])
+
+
+# _LT_HEADER_DLFCN
+# ----------------
+m4_defun([_LT_HEADER_DLFCN],
+[AC_CHECK_HEADERS([dlfcn.h], [], [], [AC_INCLUDES_DEFAULT])dnl
+])# _LT_HEADER_DLFCN
+
+
+# _LT_TRY_DLOPEN_SELF (ACTION-IF-TRUE, ACTION-IF-TRUE-W-USCORE,
+#                      ACTION-IF-FALSE, ACTION-IF-CROSS-COMPILING)
+# ----------------------------------------------------------------
+m4_defun([_LT_TRY_DLOPEN_SELF],
+[m4_require([_LT_HEADER_DLFCN])dnl
+if test yes = "$cross_compiling"; then :
+  [$4]
+else
+  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
+  lt_status=$lt_dlunknown
+  cat > conftest.$ac_ext <<_LT_EOF
+[#line $LINENO "configure"
+#include "confdefs.h"
+
+#if HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif
+
+#include <stdio.h>
+
+#ifdef RTLD_GLOBAL
+#  define LT_DLGLOBAL		RTLD_GLOBAL
+#else
+#  ifdef DL_GLOBAL
+#    define LT_DLGLOBAL		DL_GLOBAL
+#  else
+#    define LT_DLGLOBAL		0
+#  endif
+#endif
+
+/* We may have to define LT_DLLAZY_OR_NOW in the command line if we
+   find out it does not work in some platform. */
+#ifndef LT_DLLAZY_OR_NOW
+#  ifdef RTLD_LAZY
+#    define LT_DLLAZY_OR_NOW		RTLD_LAZY
+#  else
+#    ifdef DL_LAZY
+#      define LT_DLLAZY_OR_NOW		DL_LAZY
+#    else
+#      ifdef RTLD_NOW
+#        define LT_DLLAZY_OR_NOW	RTLD_NOW
+#      else
+#        ifdef DL_NOW
+#          define LT_DLLAZY_OR_NOW	DL_NOW
+#        else
+#          define LT_DLLAZY_OR_NOW	0
+#        endif
+#      endif
+#    endif
+#  endif
+#endif
+
+/* When -fvisibility=hidden is used, assume the code has been annotated
+   correspondingly for the symbols needed.  */
+#if defined __GNUC__ && (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 3))
+int fnord () __attribute__((visibility("default")));
+#endif
+
+int fnord () { return 42; }
+int main ()
+{
+  void *self = dlopen (0, LT_DLGLOBAL|LT_DLLAZY_OR_NOW);
+  int status = $lt_dlunknown;
+
+  if (self)
+    {
+      if (dlsym (self,"fnord"))       status = $lt_dlno_uscore;
+      else
+        {
+	  if (dlsym( self,"_fnord"))  status = $lt_dlneed_uscore;
+          else puts (dlerror ());
+	}
+      /* dlclose (self); */
+    }
+  else
+    puts (dlerror ());
+
+  return status;
+}]
+_LT_EOF
+  if AC_TRY_EVAL(ac_link) && test -s "conftest$ac_exeext" 2>/dev/null; then
+    (./conftest; exit; ) >&AS_MESSAGE_LOG_FD 2>/dev/null
+    lt_status=$?
+    case x$lt_status in
+      x$lt_dlno_uscore) $1 ;;
+      x$lt_dlneed_uscore) $2 ;;
+      x$lt_dlunknown|x*) $3 ;;
+    esac
+  else :
+    # compilation failed
+    $3
+  fi
+fi
+rm -fr conftest*
+])# _LT_TRY_DLOPEN_SELF
+
+
+# LT_SYS_DLOPEN_SELF
+# ------------------
+AC_DEFUN([LT_SYS_DLOPEN_SELF],
+[m4_require([_LT_HEADER_DLFCN])dnl
+if test yes != "$enable_dlopen"; then
+  enable_dlopen=unknown
+  enable_dlopen_self=unknown
+  enable_dlopen_self_static=unknown
+else
+  lt_cv_dlopen=no
+  lt_cv_dlopen_libs=
+
+  case $host_os in
+  beos*)
+    lt_cv_dlopen=load_add_on
+    lt_cv_dlopen_libs=
+    lt_cv_dlopen_self=yes
+    ;;
+
+  mingw* | pw32* | cegcc*)
+    lt_cv_dlopen=LoadLibrary
+    lt_cv_dlopen_libs=
+    ;;
+
+  cygwin*)
+    lt_cv_dlopen=dlopen
+    lt_cv_dlopen_libs=
+    ;;
+
+  darwin*)
+    # if libdl is installed we need to link against it
+    AC_CHECK_LIB([dl], [dlopen],
+		[lt_cv_dlopen=dlopen lt_cv_dlopen_libs=-ldl],[
+    lt_cv_dlopen=dyld
+    lt_cv_dlopen_libs=
+    lt_cv_dlopen_self=yes
+    ])
+    ;;
+
+  tpf*)
+    # Don't try to run any link tests for TPF.  We know it's impossible
+    # because TPF is a cross-compiler, and we know how we open DSOs.
+    lt_cv_dlopen=dlopen
+    lt_cv_dlopen_libs=
+    lt_cv_dlopen_self=no
+    ;;
+
+  *)
+    AC_CHECK_FUNC([shl_load],
+	  [lt_cv_dlopen=shl_load],
+      [AC_CHECK_LIB([dld], [shl_load],
+	    [lt_cv_dlopen=shl_load lt_cv_dlopen_libs=-ldld],
+	[AC_CHECK_FUNC([dlopen],
+	      [lt_cv_dlopen=dlopen],
+	  [AC_CHECK_LIB([dl], [dlopen],
+		[lt_cv_dlopen=dlopen lt_cv_dlopen_libs=-ldl],
+	    [AC_CHECK_LIB([svld], [dlopen],
+		  [lt_cv_dlopen=dlopen lt_cv_dlopen_libs=-lsvld],
+	      [AC_CHECK_LIB([dld], [dld_link],
+		    [lt_cv_dlopen=dld_link lt_cv_dlopen_libs=-ldld])
+	      ])
+	    ])
+	  ])
+	])
+      ])
+    ;;
+  esac
+
+  if test no = "$lt_cv_dlopen"; then
+    enable_dlopen=no
+  else
+    enable_dlopen=yes
+  fi
+
+  case $lt_cv_dlopen in
+  dlopen)
+    save_CPPFLAGS=$CPPFLAGS
+    test yes = "$ac_cv_header_dlfcn_h" && CPPFLAGS="$CPPFLAGS -DHAVE_DLFCN_H"
+
+    save_LDFLAGS=$LDFLAGS
+    wl=$lt_prog_compiler_wl eval LDFLAGS=\"\$LDFLAGS $export_dynamic_flag_spec\"
+
+    save_LIBS=$LIBS
+    LIBS="$lt_cv_dlopen_libs $LIBS"
+
+    AC_CACHE_CHECK([whether a program can dlopen itself],
+	  lt_cv_dlopen_self, [dnl
+	  _LT_TRY_DLOPEN_SELF(
+	    lt_cv_dlopen_self=yes, lt_cv_dlopen_self=yes,
+	    lt_cv_dlopen_self=no, lt_cv_dlopen_self=cross)
+    ])
+
+    if test yes = "$lt_cv_dlopen_self"; then
+      wl=$lt_prog_compiler_wl eval LDFLAGS=\"\$LDFLAGS $lt_prog_compiler_static\"
+      AC_CACHE_CHECK([whether a statically linked program can dlopen itself],
+	  lt_cv_dlopen_self_static, [dnl
+	  _LT_TRY_DLOPEN_SELF(
+	    lt_cv_dlopen_self_static=yes, lt_cv_dlopen_self_static=yes,
+	    lt_cv_dlopen_self_static=no,  lt_cv_dlopen_self_static=cross)
+      ])
+    fi
+
+    CPPFLAGS=$save_CPPFLAGS
+    LDFLAGS=$save_LDFLAGS
+    LIBS=$save_LIBS
+    ;;
+  esac
+
+  case $lt_cv_dlopen_self in
+  yes|no) enable_dlopen_self=$lt_cv_dlopen_self ;;
+  *) enable_dlopen_self=unknown ;;
+  esac
+
+  case $lt_cv_dlopen_self_static in
+  yes|no) enable_dlopen_self_static=$lt_cv_dlopen_self_static ;;
+  *) enable_dlopen_self_static=unknown ;;
+  esac
+fi
+_LT_DECL([dlopen_support], [enable_dlopen], [0],
+	 [Whether dlopen is supported])
+_LT_DECL([dlopen_self], [enable_dlopen_self], [0],
+	 [Whether dlopen of programs is supported])
+_LT_DECL([dlopen_self_static], [enable_dlopen_self_static], [0],
+	 [Whether dlopen of statically linked programs is supported])
+])# LT_SYS_DLOPEN_SELF
+
+# Old name:
+AU_ALIAS([AC_LIBTOOL_DLOPEN_SELF], [LT_SYS_DLOPEN_SELF])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_LIBTOOL_DLOPEN_SELF], [])
+
+
+# _LT_COMPILER_C_O([TAGNAME])
+# ---------------------------
+# Check to see if options -c and -o are simultaneously supported by compiler.
+# This macro does not hard code the compiler like AC_PROG_CC_C_O.
+m4_defun([_LT_COMPILER_C_O],
+[m4_require([_LT_DECL_SED])dnl
+m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+m4_require([_LT_TAG_COMPILER])dnl
+AC_CACHE_CHECK([if $compiler supports -c -o file.$ac_objext],
+  [_LT_TAGVAR(lt_cv_prog_compiler_c_o, $1)],
+  [_LT_TAGVAR(lt_cv_prog_compiler_c_o, $1)=no
+   $RM -r conftest 2>/dev/null
+   mkdir conftest
+   cd conftest
+   mkdir out
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+
+   lt_compiler_flag="-o out/conftest2.$ac_objext"
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [[^ ]]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&AS_MESSAGE_LOG_FD)
+   (eval "$lt_compile" 2>out/conftest.err)
+   ac_status=$?
+   cat out/conftest.err >&AS_MESSAGE_LOG_FD
+   echo "$as_me:$LINENO: \$? = $ac_status" >&AS_MESSAGE_LOG_FD
+   if (exit $ac_status) && test -s out/conftest2.$ac_objext
+   then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' > out/conftest.exp
+     $SED '/^$/d; /^ *+/d' out/conftest.err >out/conftest.er2
+     if test ! -s out/conftest.er2 || diff out/conftest.exp out/conftest.er2 >/dev/null; then
+       _LT_TAGVAR(lt_cv_prog_compiler_c_o, $1)=yes
+     fi
+   fi
+   chmod u+w . 2>&AS_MESSAGE_LOG_FD
+   $RM conftest*
+   # SGI C++ compiler will create directory out/ii_files/ for
+   # template instantiation
+   test -d out/ii_files && $RM out/ii_files/* && rmdir out/ii_files
+   $RM out/* && rmdir out
+   cd ..
+   $RM -r conftest
+   $RM conftest*
+])
+_LT_TAGDECL([compiler_c_o], [lt_cv_prog_compiler_c_o], [1],
+	[Does compiler simultaneously support -c and -o options?])
+])# _LT_COMPILER_C_O
+
+
+# _LT_COMPILER_FILE_LOCKS([TAGNAME])
+# ----------------------------------
+# Check to see if we can do hard links to lock some files if needed
+m4_defun([_LT_COMPILER_FILE_LOCKS],
+[m4_require([_LT_ENABLE_LOCK])dnl
+m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+_LT_COMPILER_C_O([$1])
+
+hard_links=nottested
+if test no = "$_LT_TAGVAR(lt_cv_prog_compiler_c_o, $1)" && test no != "$need_locks"; then
+  # do not overwrite the value of need_locks provided by the user
+  AC_MSG_CHECKING([if we can lock with hard links])
+  hard_links=yes
+  $RM conftest*
+  ln conftest.a conftest.b 2>/dev/null && hard_links=no
+  touch conftest.a
+  ln conftest.a conftest.b 2>&5 || hard_links=no
+  ln conftest.a conftest.b 2>/dev/null && hard_links=no
+  AC_MSG_RESULT([$hard_links])
+  if test no = "$hard_links"; then
+    AC_MSG_WARN(['$CC' does not support '-c -o', so 'make -j' may be unsafe])
+    need_locks=warn
+  fi
+else
+  need_locks=no
+fi
+_LT_DECL([], [need_locks], [1], [Must we lock files when doing compilation?])
+])# _LT_COMPILER_FILE_LOCKS
+
+
+# _LT_CHECK_OBJDIR
+# ----------------
+m4_defun([_LT_CHECK_OBJDIR],
+[AC_CACHE_CHECK([for objdir], [lt_cv_objdir],
+[rm -f .libs 2>/dev/null
+mkdir .libs 2>/dev/null
+if test -d .libs; then
+  lt_cv_objdir=.libs
+else
+  # MS-DOS does not allow filenames that begin with a dot.
+  lt_cv_objdir=_libs
+fi
+rmdir .libs 2>/dev/null])
+objdir=$lt_cv_objdir
+_LT_DECL([], [objdir], [0],
+         [The name of the directory that contains temporary libtool files])dnl
+m4_pattern_allow([LT_OBJDIR])dnl
+AC_DEFINE_UNQUOTED([LT_OBJDIR], "$lt_cv_objdir/",
+  [Define to the sub-directory where libtool stores uninstalled libraries.])
+])# _LT_CHECK_OBJDIR
+
+
+# _LT_LINKER_HARDCODE_LIBPATH([TAGNAME])
+# --------------------------------------
+# Check hardcoding attributes.
+m4_defun([_LT_LINKER_HARDCODE_LIBPATH],
+[AC_MSG_CHECKING([how to hardcode library paths into programs])
+_LT_TAGVAR(hardcode_action, $1)=
+if test -n "$_LT_TAGVAR(hardcode_libdir_flag_spec, $1)" ||
+   test -n "$_LT_TAGVAR(runpath_var, $1)" ||
+   test yes = "$_LT_TAGVAR(hardcode_automatic, $1)"; then
+
+  # We can hardcode non-existent directories.
+  if test no != "$_LT_TAGVAR(hardcode_direct, $1)" &&
+     # If the only mechanism to avoid hardcoding is shlibpath_var, we
+     # have to relink, otherwise we might link with an installed library
+     # when we should be linking with a yet-to-be-installed one
+     ## test no != "$_LT_TAGVAR(hardcode_shlibpath_var, $1)" &&
+     test no != "$_LT_TAGVAR(hardcode_minus_L, $1)"; then
+    # Linking always hardcodes the temporary library directory.
+    _LT_TAGVAR(hardcode_action, $1)=relink
+  else
+    # We can link without hardcoding, and we can hardcode nonexisting dirs.
+    _LT_TAGVAR(hardcode_action, $1)=immediate
+  fi
+else
+  # We cannot hardcode anything, or else we can only hardcode existing
+  # directories.
+  _LT_TAGVAR(hardcode_action, $1)=unsupported
+fi
+AC_MSG_RESULT([$_LT_TAGVAR(hardcode_action, $1)])
+
+if test relink = "$_LT_TAGVAR(hardcode_action, $1)" ||
+   test yes = "$_LT_TAGVAR(inherit_rpath, $1)"; then
+  # Fast installation is not supported
+  enable_fast_install=no
+elif test yes = "$shlibpath_overrides_runpath" ||
+     test no = "$enable_shared"; then
+  # Fast installation is not necessary
+  enable_fast_install=needless
+fi
+_LT_TAGDECL([], [hardcode_action], [0],
+    [How to hardcode a shared library path into an executable])
+])# _LT_LINKER_HARDCODE_LIBPATH
+
+
+# _LT_CMD_STRIPLIB
+# ----------------
+m4_defun([_LT_CMD_STRIPLIB],
+[m4_require([_LT_DECL_EGREP])
+striplib=
+old_striplib=
+AC_MSG_CHECKING([whether stripping libraries is possible])
+if test -n "$STRIP" && $STRIP -V 2>&1 | $GREP "GNU strip" >/dev/null; then
+  test -z "$old_striplib" && old_striplib="$STRIP --strip-debug"
+  test -z "$striplib" && striplib="$STRIP --strip-unneeded"
+  AC_MSG_RESULT([yes])
+else
+# FIXME - insert some real tests, host_os isn't really good enough
+  case $host_os in
+  darwin*)
+    if test -n "$STRIP"; then
+      striplib="$STRIP -x"
+      old_striplib="$STRIP -S"
+      AC_MSG_RESULT([yes])
+    else
+      AC_MSG_RESULT([no])
+    fi
+    ;;
+  *)
+    AC_MSG_RESULT([no])
+    ;;
+  esac
+fi
+_LT_DECL([], [old_striplib], [1], [Commands to strip libraries])
+_LT_DECL([], [striplib], [1])
+])# _LT_CMD_STRIPLIB
+
+
+# _LT_PREPARE_MUNGE_PATH_LIST
+# ---------------------------
+# Make sure func_munge_path_list() is defined correctly.
+m4_defun([_LT_PREPARE_MUNGE_PATH_LIST],
+[[# func_munge_path_list VARIABLE PATH
+# -----------------------------------
+# VARIABLE is name of variable containing _space_ separated list of
+# directories to be munged by the contents of PATH, which is string
+# having a format:
+# "DIR[:DIR]:"
+#       string "DIR[ DIR]" will be prepended to VARIABLE
+# ":DIR[:DIR]"
+#       string "DIR[ DIR]" will be appended to VARIABLE
+# "DIRP[:DIRP]::[DIRA:]DIRA"
+#       string "DIRP[ DIRP]" will be prepended to VARIABLE and string
+#       "DIRA[ DIRA]" will be appended to VARIABLE
+# "DIR[:DIR]"
+#       VARIABLE will be replaced by "DIR[ DIR]"
+func_munge_path_list ()
+{
+    case x@S|@2 in
+    x)
+        ;;
+    *:)
+        eval @S|@1=\"`$ECHO @S|@2 | $SED 's/:/ /g'` \@S|@@S|@1\"
+        ;;
+    x:*)
+        eval @S|@1=\"\@S|@@S|@1 `$ECHO @S|@2 | $SED 's/:/ /g'`\"
+        ;;
+    *::*)
+        eval @S|@1=\"\@S|@@S|@1\ `$ECHO @S|@2 | $SED -e 's/.*:://' -e 's/:/ /g'`\"
+        eval @S|@1=\"`$ECHO @S|@2 | $SED -e 's/::.*//' -e 's/:/ /g'`\ \@S|@@S|@1\"
+        ;;
+    *)
+        eval @S|@1=\"`$ECHO @S|@2 | $SED 's/:/ /g'`\"
+        ;;
+    esac
+}
+]])# _LT_PREPARE_PATH_LIST
+
+
+# _LT_SYS_DYNAMIC_LINKER([TAG])
+# -----------------------------
+# PORTME Fill in your ld.so characteristics
+m4_defun([_LT_SYS_DYNAMIC_LINKER],
+[AC_REQUIRE([AC_CANONICAL_HOST])dnl
+m4_require([_LT_DECL_EGREP])dnl
+m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+m4_require([_LT_DECL_OBJDUMP])dnl
+m4_require([_LT_DECL_SED])dnl
+m4_require([_LT_CHECK_SHELL_FEATURES])dnl
+m4_require([_LT_PREPARE_MUNGE_PATH_LIST])dnl
+AC_MSG_CHECKING([dynamic linker characteristics])
+m4_if([$1],
+	[], [
+if test yes = "$GCC"; then
+  case $host_os in
+    darwin*) lt_awk_arg='/^libraries:/,/LR/' ;;
+    *) lt_awk_arg='/^libraries:/' ;;
+  esac
+  case $host_os in
+    mingw* | cegcc*) lt_sed_strip_eq='s|=\([[A-Za-z]]:\)|\1|g' ;;
+    *) lt_sed_strip_eq='s|=/|/|g' ;;
+  esac
+  lt_search_path_spec=`$CC -print-search-dirs | awk $lt_awk_arg | $SED -e "s/^libraries://" -e $lt_sed_strip_eq`
+  case $lt_search_path_spec in
+  *\;*)
+    # if the path contains ";" then we assume it to be the separator
+    # otherwise default to the standard path separator (i.e. ":") - it is
+    # assumed that no part of a normal pathname contains ";" but that should
+    # okay in the real world where ";" in dirpaths is itself problematic.
+    lt_search_path_spec=`$ECHO "$lt_search_path_spec" | $SED 's/;/ /g'`
+    ;;
+  *)
+    lt_search_path_spec=`$ECHO "$lt_search_path_spec" | $SED "s/$PATH_SEPARATOR/ /g"`
+    ;;
+  esac
+  # Ok, now we have the path, separated by spaces, we can step through it
+  # and add multilib dir if necessary...
+  lt_tmp_lt_search_path_spec=
+  lt_multi_os_dir=/`$CC $CPPFLAGS $CFLAGS $LDFLAGS -print-multi-os-directory 2>/dev/null`
+  # ...but if some path component already ends with the multilib dir we assume
+  # that all is fine and trust -print-search-dirs as is (GCC 4.2? or newer).
+  case "$lt_multi_os_dir; $lt_search_path_spec " in
+  "/; "* | "/.; "* | "/./; "* | *"$lt_multi_os_dir "* | *"$lt_multi_os_dir/ "*)
+    lt_multi_os_dir=
+    ;;
+  esac
+  for lt_sys_path in $lt_search_path_spec; do
+    if test -d "$lt_sys_path$lt_multi_os_dir"; then
+      lt_tmp_lt_search_path_spec="$lt_tmp_lt_search_path_spec $lt_sys_path$lt_multi_os_dir"
+    elif test -n "$lt_multi_os_dir"; then
+      test -d "$lt_sys_path" && \
+	lt_tmp_lt_search_path_spec="$lt_tmp_lt_search_path_spec $lt_sys_path"
+    fi
+  done
+  lt_search_path_spec=`$ECHO "$lt_tmp_lt_search_path_spec" | awk '
+BEGIN {RS = " "; FS = "/|\n";} {
+  lt_foo = "";
+  lt_count = 0;
+  for (lt_i = NF; lt_i > 0; lt_i--) {
+    if ($lt_i != "" && $lt_i != ".") {
+      if ($lt_i == "..") {
+        lt_count++;
+      } else {
+        if (lt_count == 0) {
+          lt_foo = "/" $lt_i lt_foo;
+        } else {
+          lt_count--;
+        }
+      }
+    }
+  }
+  if (lt_foo != "") { lt_freq[[lt_foo]]++; }
+  if (lt_freq[[lt_foo]] == 1) { print lt_foo; }
+}'`
+  # AWK program above erroneously prepends '/' to C:/dos/paths
+  # for these hosts.
+  case $host_os in
+    mingw* | cegcc*) lt_search_path_spec=`$ECHO "$lt_search_path_spec" |\
+      $SED 's|/\([[A-Za-z]]:\)|\1|g'` ;;
+  esac
+  sys_lib_search_path_spec=`$ECHO "$lt_search_path_spec" | $lt_NL2SP`
+else
+  sys_lib_search_path_spec="/lib /usr/lib /usr/local/lib"
+fi])
+library_names_spec=
+libname_spec='lib$name'
+soname_spec=
+shrext_cmds=.so
+postinstall_cmds=
+postuninstall_cmds=
+finish_cmds=
+finish_eval=
+shlibpath_var=
+shlibpath_overrides_runpath=unknown
+version_type=none
+dynamic_linker="$host_os ld.so"
+sys_lib_dlsearch_path_spec="/lib /usr/lib"
+need_lib_prefix=unknown
+hardcode_into_libs=no
+
+# when you set need_version to no, make sure it does not cause -set_version
+# flags to be left without arguments
+need_version=unknown
+
+AC_ARG_VAR([LT_SYS_LIBRARY_PATH],
+[User-defined run-time library search path.])
+
+case $host_os in
+aix3*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname.a'
+  shlibpath_var=LIBPATH
+
+  # AIX 3 has no versioning support, so we append a major version to the name.
+  soname_spec='$libname$release$shared_ext$major'
+  ;;
+
+aix[[4-9]]*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  hardcode_into_libs=yes
+  if test ia64 = "$host_cpu"; then
+    # AIX 5 supports IA64
+    library_names_spec='$libname$release$shared_ext$major $libname$release$shared_ext$versuffix $libname$shared_ext'
+    shlibpath_var=LD_LIBRARY_PATH
+  else
+    # With GCC up to 2.95.x, collect2 would create an import file
+    # for dependence libraries.  The import file would start with
+    # the line '#! .'.  This would cause the generated library to
+    # depend on '.', always an invalid library.  This was fixed in
+    # development snapshots of GCC prior to 3.0.
+    case $host_os in
+      aix4 | aix4.[[01]] | aix4.[[01]].*)
+      if { echo '#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 97)'
+	   echo ' yes '
+	   echo '#endif'; } | $CC -E - | $GREP yes > /dev/null; then
+	:
+      else
+	can_build_shared=no
+      fi
+      ;;
+    esac
+    # Using Import Files as archive members, it is possible to support
+    # filename-based versioning of shared library archives on AIX. While
+    # this would work for both with and without runtime linking, it will
+    # prevent static linking of such archives. So we do filename-based
+    # shared library versioning with .so extension only, which is used
+    # when both runtime linking and shared linking is enabled.
+    # Unfortunately, runtime linking may impact performance, so we do
+    # not want this to be the default eventually. Also, we use the
+    # versioned .so libs for executables only if there is the -brtl
+    # linker flag in LDFLAGS as well, or --with-aix-soname=svr4 only.
+    # To allow for filename-based versioning support, we need to create
+    # libNAME.so.V as an archive file, containing:
+    # *) an Import File, referring to the versioned filename of the
+    #    archive as well as the shared archive member, telling the
+    #    bitwidth (32 or 64) of that shared object, and providing the
+    #    list of exported symbols of that shared object, eventually
+    #    decorated with the 'weak' keyword
+    # *) the shared object with the F_LOADONLY flag set, to really avoid
+    #    it being seen by the linker.
+    # At run time we better use the real file rather than another symlink,
+    # but for link time we create the symlink libNAME.so -> libNAME.so.V
+
+    case $with_aix_soname,$aix_use_runtimelinking in
+    # AIX (on Power*) has no versioning support, so currently we cannot hardcode correct
+    # soname into executable. Probably we can add versioning support to
+    # collect2, so additional links can be useful in future.
+    aix,yes) # traditional libtool
+      dynamic_linker='AIX unversionable lib.so'
+      # If using run time linking (on AIX 4.2 or later) use lib<name>.so
+      # instead of lib<name>.a to let people know that these are not
+      # typical AIX shared libraries.
+      library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+      ;;
+    aix,no) # traditional AIX only
+      dynamic_linker='AIX lib.a[(]lib.so.V[)]'
+      # We preserve .a as extension for shared libraries through AIX4.2
+      # and later when we are not doing run time linking.
+      library_names_spec='$libname$release.a $libname.a'
+      soname_spec='$libname$release$shared_ext$major'
+      ;;
+    svr4,*) # full svr4 only
+      dynamic_linker="AIX lib.so.V[(]$shared_archive_member_spec.o[)]"
+      library_names_spec='$libname$release$shared_ext$major $libname$shared_ext'
+      # We do not specify a path in Import Files, so LIBPATH fires.
+      shlibpath_overrides_runpath=yes
+      ;;
+    *,yes) # both, prefer svr4
+      dynamic_linker="AIX lib.so.V[(]$shared_archive_member_spec.o[)], lib.a[(]lib.so.V[)]"
+      library_names_spec='$libname$release$shared_ext$major $libname$shared_ext'
+      # unpreferred sharedlib libNAME.a needs extra handling
+      postinstall_cmds='test -n "$linkname" || linkname="$realname"~func_stripname "" ".so" "$linkname"~$install_shared_prog "$dir/$func_stripname_result.$libext" "$destdir/$func_stripname_result.$libext"~test -z "$tstripme" || test -z "$striplib" || $striplib "$destdir/$func_stripname_result.$libext"'
+      postuninstall_cmds='for n in $library_names $old_library; do :; done~func_stripname "" ".so" "$n"~test "$func_stripname_result" = "$n" || func_append rmfiles " $odir/$func_stripname_result.$libext"'
+      # We do not specify a path in Import Files, so LIBPATH fires.
+      shlibpath_overrides_runpath=yes
+      ;;
+    *,no) # both, prefer aix
+      dynamic_linker="AIX lib.a[(]lib.so.V[)], lib.so.V[(]$shared_archive_member_spec.o[)]"
+      library_names_spec='$libname$release.a $libname.a'
+      soname_spec='$libname$release$shared_ext$major'
+      # unpreferred sharedlib libNAME.so.V and symlink libNAME.so need extra handling
+      postinstall_cmds='test -z "$dlname" || $install_shared_prog $dir/$dlname $destdir/$dlname~test -z "$tstripme" || test -z "$striplib" || $striplib $destdir/$dlname~test -n "$linkname" || linkname=$realname~func_stripname "" ".a" "$linkname"~(cd "$destdir" && $LN_S -f $dlname $func_stripname_result.so)'
+      postuninstall_cmds='test -z "$dlname" || func_append rmfiles " $odir/$dlname"~for n in $old_library $library_names; do :; done~func_stripname "" ".a" "$n"~func_append rmfiles " $odir/$func_stripname_result.so"'
+      ;;
+    esac
+    shlibpath_var=LIBPATH
+  fi
+  ;;
+
+amigaos*)
+  case $host_cpu in
+  powerpc)
+    # Since July 2007 AmigaOS4 officially supports .so libraries.
+    # When compiling the executable, add -use-dynld -Lsobjs: to the compileline.
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    ;;
+  m68k)
+    library_names_spec='$libname.ixlibrary $libname.a'
+    # Create ${libname}_ixlibrary.a entries in /sys/libs.
+    finish_eval='for lib in `ls $libdir/*.ixlibrary 2>/dev/null`; do libname=`func_echo_all "$lib" | $SED '\''s%^.*/\([[^/]]*\)\.ixlibrary$%\1%'\''`; $RM /sys/libs/${libname}_ixlibrary.a; $show "cd /sys/libs && $LN_S $lib ${libname}_ixlibrary.a"; cd /sys/libs && $LN_S $lib ${libname}_ixlibrary.a || exit 1; done'
+    ;;
+  esac
+  ;;
+
+beos*)
+  library_names_spec='$libname$shared_ext'
+  dynamic_linker="$host_os ld.so"
+  shlibpath_var=LIBRARY_PATH
+  ;;
+
+bsdi[[45]]*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  finish_cmds='PATH="\$PATH:/sbin" ldconfig $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  sys_lib_search_path_spec="/shlib /usr/lib /usr/X11/lib /usr/contrib/lib /lib /usr/local/lib"
+  sys_lib_dlsearch_path_spec="/shlib /usr/lib /usr/local/lib"
+  # the default ld.so.conf also contains /usr/contrib/lib and
+  # /usr/X11R6/lib (/usr/X11 is a link to /usr/X11R6), but let us allow
+  # libtool to hard-code these into programs
+  ;;
+
+cygwin* | mingw* | pw32* | cegcc*)
+  version_type=windows
+  shrext_cmds=.dll
+  need_version=no
+  need_lib_prefix=no
+
+  case $GCC,$cc_basename in
+  yes,*)
+    # gcc
+    library_names_spec='$libname.dll.a'
+    # DLL is installed to $(libdir)/../bin by postinstall_cmds
+    postinstall_cmds='base_file=`basename \$file`~
+      dlpath=`$SHELL 2>&1 -c '\''. $dir/'\''\$base_file'\''i; echo \$dlname'\''`~
+      dldir=$destdir/`dirname \$dlpath`~
+      test -d \$dldir || mkdir -p \$dldir~
+      $install_prog $dir/$dlname \$dldir/$dlname~
+      chmod a+x \$dldir/$dlname~
+      if test -n '\''$stripme'\'' && test -n '\''$striplib'\''; then
+        eval '\''$striplib \$dldir/$dlname'\'' || exit \$?;
+      fi'
+    postuninstall_cmds='dldll=`$SHELL 2>&1 -c '\''. $file; echo \$dlname'\''`~
+      dlpath=$dir/\$dldll~
+       $RM \$dlpath'
+    shlibpath_overrides_runpath=yes
+
+    case $host_os in
+    cygwin*)
+      # Cygwin DLLs use 'cyg' prefix rather than 'lib'
+      soname_spec='`echo $libname | sed -e 's/^lib/cyg/'``echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
+m4_if([$1], [],[
+      sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/lib/w32api"])
+      ;;
+    mingw* | cegcc*)
+      # MinGW DLLs use traditional 'lib' prefix
+      soname_spec='$libname`echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
+      ;;
+    pw32*)
+      # pw32 DLLs use 'pw' prefix rather than 'lib'
+      library_names_spec='`echo $libname | sed -e 's/^lib/pw/'``echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
+      ;;
+    esac
+    dynamic_linker='Win32 ld.exe'
+    ;;
+
+  *,cl*)
+    # Native MSVC
+    libname_spec='$name'
+    soname_spec='$libname`echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
+    library_names_spec='$libname.dll.lib'
+
+    case $build_os in
+    mingw*)
+      sys_lib_search_path_spec=
+      lt_save_ifs=$IFS
+      IFS=';'
+      for lt_path in $LIB
+      do
+        IFS=$lt_save_ifs
+        # Let DOS variable expansion print the short 8.3 style file name.
+        lt_path=`cd "$lt_path" 2>/dev/null && cmd //C "for %i in (".") do @echo %~si"`
+        sys_lib_search_path_spec="$sys_lib_search_path_spec $lt_path"
+      done
+      IFS=$lt_save_ifs
+      # Convert to MSYS style.
+      sys_lib_search_path_spec=`$ECHO "$sys_lib_search_path_spec" | sed -e 's|\\\\|/|g' -e 's| \\([[a-zA-Z]]\\):| /\\1|g' -e 's|^ ||'`
+      ;;
+    cygwin*)
+      # Convert to unix form, then to dos form, then back to unix form
+      # but this time dos style (no spaces!) so that the unix form looks
+      # like /cygdrive/c/PROGRA~1:/cygdr...
+      sys_lib_search_path_spec=`cygpath --path --unix "$LIB"`
+      sys_lib_search_path_spec=`cygpath --path --dos "$sys_lib_search_path_spec" 2>/dev/null`
+      sys_lib_search_path_spec=`cygpath --path --unix "$sys_lib_search_path_spec" | $SED -e "s/$PATH_SEPARATOR/ /g"`
+      ;;
+    *)
+      sys_lib_search_path_spec=$LIB
+      if $ECHO "$sys_lib_search_path_spec" | [$GREP ';[c-zC-Z]:/' >/dev/null]; then
+        # It is most probably a Windows format PATH.
+        sys_lib_search_path_spec=`$ECHO "$sys_lib_search_path_spec" | $SED -e 's/;/ /g'`
+      else
+        sys_lib_search_path_spec=`$ECHO "$sys_lib_search_path_spec" | $SED -e "s/$PATH_SEPARATOR/ /g"`
+      fi
+      # FIXME: find the short name or the path components, as spaces are
+      # common. (e.g. "Program Files" -> "PROGRA~1")
+      ;;
+    esac
+
+    # DLL is installed to $(libdir)/../bin by postinstall_cmds
+    postinstall_cmds='base_file=`basename \$file`~
+      dlpath=`$SHELL 2>&1 -c '\''. $dir/'\''\$base_file'\''i; echo \$dlname'\''`~
+      dldir=$destdir/`dirname \$dlpath`~
+      test -d \$dldir || mkdir -p \$dldir~
+      $install_prog $dir/$dlname \$dldir/$dlname'
+    postuninstall_cmds='dldll=`$SHELL 2>&1 -c '\''. $file; echo \$dlname'\''`~
+      dlpath=$dir/\$dldll~
+       $RM \$dlpath'
+    shlibpath_overrides_runpath=yes
+    dynamic_linker='Win32 link.exe'
+    ;;
+
+  *)
+    # Assume MSVC wrapper
+    library_names_spec='$libname`echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext $libname.lib'
+    dynamic_linker='Win32 ld.exe'
+    ;;
+  esac
+  # FIXME: first we should search . and the directory the executable is in
+  shlibpath_var=PATH
+  ;;
+
+darwin* | rhapsody*)
+  dynamic_linker="$host_os dyld"
+  version_type=darwin
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$major$shared_ext $libname$shared_ext'
+  soname_spec='$libname$release$major$shared_ext'
+  shlibpath_overrides_runpath=yes
+  shlibpath_var=DYLD_LIBRARY_PATH
+  shrext_cmds='`test .$module = .yes && echo .so || echo .dylib`'
+m4_if([$1], [],[
+  sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/local/lib"])
+  sys_lib_dlsearch_path_spec='/usr/local/lib /lib /usr/lib'
+  ;;
+
+dgux*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  ;;
+
+freebsd* | dragonfly*)
+  # DragonFly does not have aout.  When/if they implement a new
+  # versioning mechanism, adjust this.
+  if test -x /usr/bin/objformat; then
+    objformat=`/usr/bin/objformat`
+  else
+    case $host_os in
+    freebsd[[23]].*) objformat=aout ;;
+    *) objformat=elf ;;
+    esac
+  fi
+  version_type=freebsd-$objformat
+  case $version_type in
+    freebsd-elf*)
+      library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+      soname_spec='$libname$release$shared_ext$major'
+      need_version=no
+      need_lib_prefix=no
+      ;;
+    freebsd-*)
+      library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+      need_version=yes
+      ;;
+  esac
+  shlibpath_var=LD_LIBRARY_PATH
+  case $host_os in
+  freebsd2.*)
+    shlibpath_overrides_runpath=yes
+    ;;
+  freebsd3.[[01]]* | freebsdelf3.[[01]]*)
+    shlibpath_overrides_runpath=yes
+    hardcode_into_libs=yes
+    ;;
+  freebsd3.[[2-9]]* | freebsdelf3.[[2-9]]* | \
+  freebsd4.[[0-5]] | freebsdelf4.[[0-5]] | freebsd4.1.1 | freebsdelf4.1.1)
+    shlibpath_overrides_runpath=no
+    hardcode_into_libs=yes
+    ;;
+  *) # from 4.6 on, and DragonFly
+    shlibpath_overrides_runpath=yes
+    hardcode_into_libs=yes
+    ;;
+  esac
+  ;;
+
+haiku*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  dynamic_linker="$host_os runtime_loader"
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  sys_lib_dlsearch_path_spec='/boot/home/config/lib /boot/common/lib /boot/system/lib'
+  hardcode_into_libs=yes
+  ;;
+
+hpux9* | hpux10* | hpux11*)
+  # Give a soname corresponding to the major version so that dld.sl refuses to
+  # link against other versions.
+  version_type=sunos
+  need_lib_prefix=no
+  need_version=no
+  case $host_cpu in
+  ia64*)
+    shrext_cmds='.so'
+    hardcode_into_libs=yes
+    dynamic_linker="$host_os dld.so"
+    shlibpath_var=LD_LIBRARY_PATH
+    shlibpath_overrides_runpath=yes # Unless +noenvvar is specified.
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    if test 32 = "$HPUX_IA64_MODE"; then
+      sys_lib_search_path_spec="/usr/lib/hpux32 /usr/local/lib/hpux32 /usr/local/lib"
+      sys_lib_dlsearch_path_spec=/usr/lib/hpux32
+    else
+      sys_lib_search_path_spec="/usr/lib/hpux64 /usr/local/lib/hpux64"
+      sys_lib_dlsearch_path_spec=/usr/lib/hpux64
+    fi
+    ;;
+  hppa*64*)
+    shrext_cmds='.sl'
+    hardcode_into_libs=yes
+    dynamic_linker="$host_os dld.sl"
+    shlibpath_var=LD_LIBRARY_PATH # How should we handle SHLIB_PATH
+    shlibpath_overrides_runpath=yes # Unless +noenvvar is specified.
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    sys_lib_search_path_spec="/usr/lib/pa20_64 /usr/ccs/lib/pa20_64"
+    sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
+    ;;
+  *)
+    shrext_cmds='.sl'
+    dynamic_linker="$host_os dld.sl"
+    shlibpath_var=SHLIB_PATH
+    shlibpath_overrides_runpath=no # +s is required to enable SHLIB_PATH
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    ;;
+  esac
+  # HP-UX runs *really* slowly unless shared libraries are mode 555, ...
+  postinstall_cmds='chmod 555 $lib'
+  # or fails outright, so override atomically:
+  install_override_mode=555
+  ;;
+
+interix[[3-9]]*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  dynamic_linker='Interix 3.x ld.so.1 (PE, like ELF)'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  ;;
+
+irix5* | irix6* | nonstopux*)
+  case $host_os in
+    nonstopux*) version_type=nonstopux ;;
+    *)
+	if test yes = "$lt_cv_prog_gnu_ld"; then
+		version_type=linux # correct to gnu/linux during the next big refactor
+	else
+		version_type=irix
+	fi ;;
+  esac
+  need_lib_prefix=no
+  need_version=no
+  soname_spec='$libname$release$shared_ext$major'
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$release$shared_ext $libname$shared_ext'
+  case $host_os in
+  irix5* | nonstopux*)
+    libsuff= shlibsuff=
+    ;;
+  *)
+    case $LD in # libtool.m4 will add one of these switches to LD
+    *-32|*"-32 "|*-melf32bsmip|*"-melf32bsmip ")
+      libsuff= shlibsuff= libmagic=32-bit;;
+    *-n32|*"-n32 "|*-melf32bmipn32|*"-melf32bmipn32 ")
+      libsuff=32 shlibsuff=N32 libmagic=N32;;
+    *-64|*"-64 "|*-melf64bmip|*"-melf64bmip ")
+      libsuff=64 shlibsuff=64 libmagic=64-bit;;
+    *) libsuff= shlibsuff= libmagic=never-match;;
+    esac
+    ;;
+  esac
+  shlibpath_var=LD_LIBRARY${shlibsuff}_PATH
+  shlibpath_overrides_runpath=no
+  sys_lib_search_path_spec="/usr/lib$libsuff /lib$libsuff /usr/local/lib$libsuff"
+  sys_lib_dlsearch_path_spec="/usr/lib$libsuff /lib$libsuff"
+  hardcode_into_libs=yes
+  ;;
+
+# No shared lib support for Linux oldld, aout, or coff.
+linux*oldld* | linux*aout* | linux*coff*)
+  dynamic_linker=no
+  ;;
+
+linux*android*)
+  version_type=none # Android doesn't support versioned libraries.
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext'
+  soname_spec='$libname$release$shared_ext'
+  finish_cmds=
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+
+  # This implies no fast_install, which is unacceptable.
+  # Some rework will be needed to allow for fast_install
+  # before this can be enabled.
+  hardcode_into_libs=yes
+
+  dynamic_linker='Android linker'
+  # Don't embed -rpath directories since the linker doesn't support them.
+  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+  ;;
+
+# This must be glibc/ELF.
+linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  finish_cmds='PATH="\$PATH:/sbin" ldconfig -n $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+
+  # Some binutils ld are patched to set DT_RUNPATH
+  AC_CACHE_VAL([lt_cv_shlibpath_overrides_runpath],
+    [lt_cv_shlibpath_overrides_runpath=no
+    save_LDFLAGS=$LDFLAGS
+    save_libdir=$libdir
+    eval "libdir=/foo; wl=\"$_LT_TAGVAR(lt_prog_compiler_wl, $1)\"; \
+	 LDFLAGS=\"\$LDFLAGS $_LT_TAGVAR(hardcode_libdir_flag_spec, $1)\""
+    AC_LINK_IFELSE([AC_LANG_PROGRAM([],[])],
+      [AS_IF([ ($OBJDUMP -p conftest$ac_exeext) 2>/dev/null | grep "RUNPATH.*$libdir" >/dev/null],
+	 [lt_cv_shlibpath_overrides_runpath=yes])])
+    LDFLAGS=$save_LDFLAGS
+    libdir=$save_libdir
+    ])
+  shlibpath_overrides_runpath=$lt_cv_shlibpath_overrides_runpath
+
+  # This implies no fast_install, which is unacceptable.
+  # Some rework will be needed to allow for fast_install
+  # before this can be enabled.
+  hardcode_into_libs=yes
+
+  # Ideally, we could use ldconfig to report *all* directores which are
+  # searched for libraries, however this is still not possible.  Aside from not
+  # being certain /sbin/ldconfig is available, command
+  # 'ldconfig -N -X -v | grep ^/' on 64bit Fedora does not report /usr/lib64,
+  # even though it is searched at run-time.  Try to do the best guess by
+  # appending ld.so.conf contents (and includes) to the search path.
+  if test -f /etc/ld.so.conf; then
+    lt_ld_extra=`awk '/^include / { system(sprintf("cd /etc; cat %s 2>/dev/null", \[$]2)); skip = 1; } { if (!skip) print \[$]0; skip = 0; }' < /etc/ld.so.conf | $SED -e 's/#.*//;/^[	 ]*hwcap[	 ]/d;s/[:,	]/ /g;s/=[^=]*$//;s/=[^= ]* / /g;s/"//g;/^$/d' | tr '\n' ' '`
+    sys_lib_dlsearch_path_spec="/lib /usr/lib $lt_ld_extra"
+  fi
+
+  # We used to test for /lib/ld.so.1 and disable shared libraries on
+  # powerpc, because MkLinux only supported shared libraries with the
+  # GNU dynamic linker.  Since this was broken with cross compilers,
+  # most powerpc-linux boxes support dynamic linking these days and
+  # people can always --disable-shared, the test was removed, and we
+  # assume the GNU/Linux dynamic linker is in use.
+  dynamic_linker='GNU/Linux ld.so'
+  ;;
+
+netbsd*)
+  version_type=sunos
+  need_lib_prefix=no
+  need_version=no
+  if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+    finish_cmds='PATH="\$PATH:/sbin" ldconfig -m $libdir'
+    dynamic_linker='NetBSD (a.out) ld.so'
+  else
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    dynamic_linker='NetBSD ld.elf_so'
+  fi
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  hardcode_into_libs=yes
+  ;;
+
+newsos6)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  ;;
+
+*nto* | *qnx*)
+  version_type=qnx
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  dynamic_linker='ldqnx.so'
+  ;;
+
+openbsd* | bitrig*)
+  version_type=sunos
+  sys_lib_dlsearch_path_spec=/usr/lib
+  need_lib_prefix=no
+  if test -z "`echo __ELF__ | $CC -E - | $GREP __ELF__`"; then
+    need_version=no
+  else
+    need_version=yes
+  fi
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+  finish_cmds='PATH="\$PATH:/sbin" ldconfig -m $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  ;;
+
+os2*)
+  libname_spec='$name'
+  version_type=windows
+  shrext_cmds=.dll
+  need_version=no
+  need_lib_prefix=no
+  # OS/2 can only load a DLL with a base name of 8 characters or less.
+  soname_spec='`test -n "$os2dllname" && libname="$os2dllname";
+    v=$($ECHO $release$versuffix | tr -d .-);
+    n=$($ECHO $libname | cut -b -$((8 - ${#v})) | tr . _);
+    $ECHO $n$v`$shared_ext'
+  library_names_spec='${libname}_dll.$libext'
+  dynamic_linker='OS/2 ld.exe'
+  shlibpath_var=BEGINLIBPATH
+  sys_lib_search_path_spec="/lib /usr/lib /usr/local/lib"
+  sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
+  postinstall_cmds='base_file=`basename \$file`~
+    dlpath=`$SHELL 2>&1 -c '\''. $dir/'\''\$base_file'\''i; $ECHO \$dlname'\''`~
+    dldir=$destdir/`dirname \$dlpath`~
+    test -d \$dldir || mkdir -p \$dldir~
+    $install_prog $dir/$dlname \$dldir/$dlname~
+    chmod a+x \$dldir/$dlname~
+    if test -n '\''$stripme'\'' && test -n '\''$striplib'\''; then
+      eval '\''$striplib \$dldir/$dlname'\'' || exit \$?;
+    fi'
+  postuninstall_cmds='dldll=`$SHELL 2>&1 -c '\''. $file; $ECHO \$dlname'\''`~
+    dlpath=$dir/\$dldll~
+    $RM \$dlpath'
+  ;;
+
+osf3* | osf4* | osf5*)
+  version_type=osf
+  need_lib_prefix=no
+  need_version=no
+  soname_spec='$libname$release$shared_ext$major'
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  shlibpath_var=LD_LIBRARY_PATH
+  sys_lib_search_path_spec="/usr/shlib /usr/ccs/lib /usr/lib/cmplrs/cc /usr/lib /usr/local/lib /var/shlib"
+  sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
+  ;;
+
+rdos*)
+  dynamic_linker=no
+  ;;
+
+solaris*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  hardcode_into_libs=yes
+  # ldd complains unless libraries are executable
+  postinstall_cmds='chmod +x $lib'
+  ;;
+
+sunos4*)
+  version_type=sunos
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+  finish_cmds='PATH="\$PATH:/usr/etc" ldconfig $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  if test yes = "$with_gnu_ld"; then
+    need_lib_prefix=no
+  fi
+  need_version=yes
+  ;;
+
+sysv4 | sysv4.3*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  case $host_vendor in
+    sni)
+      shlibpath_overrides_runpath=no
+      need_lib_prefix=no
+      runpath_var=LD_RUN_PATH
+      ;;
+    siemens)
+      need_lib_prefix=no
+      ;;
+    motorola)
+      need_lib_prefix=no
+      need_version=no
+      shlibpath_overrides_runpath=no
+      sys_lib_search_path_spec='/lib /usr/lib /usr/ccs/lib'
+      ;;
+  esac
+  ;;
+
+sysv4*MP*)
+  if test -d /usr/nec; then
+    version_type=linux # correct to gnu/linux during the next big refactor
+    library_names_spec='$libname$shared_ext.$versuffix $libname$shared_ext.$major $libname$shared_ext'
+    soname_spec='$libname$shared_ext.$major'
+    shlibpath_var=LD_LIBRARY_PATH
+  fi
+  ;;
+
+sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX* | sysv4*uw2*)
+  version_type=sco
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  hardcode_into_libs=yes
+  if test yes = "$with_gnu_ld"; then
+    sys_lib_search_path_spec='/usr/local/lib /usr/gnu/lib /usr/ccs/lib /usr/lib /lib'
+  else
+    sys_lib_search_path_spec='/usr/ccs/lib /usr/lib'
+    case $host_os in
+      sco3.2v5*)
+        sys_lib_search_path_spec="$sys_lib_search_path_spec /lib"
+	;;
+    esac
+  fi
+  sys_lib_dlsearch_path_spec='/usr/lib'
+  ;;
+
+tpf*)
+  # TPF is a cross-target only.  Preferred cross-host = GNU/Linux.
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  ;;
+
+uts4*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  ;;
+
+*)
+  dynamic_linker=no
+  ;;
+esac
+AC_MSG_RESULT([$dynamic_linker])
+test no = "$dynamic_linker" && can_build_shared=no
+
+variables_saved_for_relink="PATH $shlibpath_var $runpath_var"
+if test yes = "$GCC"; then
+  variables_saved_for_relink="$variables_saved_for_relink GCC_EXEC_PREFIX COMPILER_PATH LIBRARY_PATH"
+fi
+
+if test set = "${lt_cv_sys_lib_search_path_spec+set}"; then
+  sys_lib_search_path_spec=$lt_cv_sys_lib_search_path_spec
+fi
+
+if test set = "${lt_cv_sys_lib_dlsearch_path_spec+set}"; then
+  sys_lib_dlsearch_path_spec=$lt_cv_sys_lib_dlsearch_path_spec
+fi
+
+# remember unaugmented sys_lib_dlsearch_path content for libtool script decls...
+configure_time_dlsearch_path=$sys_lib_dlsearch_path_spec
+
+# ... but it needs LT_SYS_LIBRARY_PATH munging for other configure-time code
+func_munge_path_list sys_lib_dlsearch_path_spec "$LT_SYS_LIBRARY_PATH"
+
+# to be used as default LT_SYS_LIBRARY_PATH value in generated libtool
+configure_time_lt_sys_library_path=$LT_SYS_LIBRARY_PATH
+
+_LT_DECL([], [variables_saved_for_relink], [1],
+    [Variables whose values should be saved in libtool wrapper scripts and
+    restored at link time])
+_LT_DECL([], [need_lib_prefix], [0],
+    [Do we need the "lib" prefix for modules?])
+_LT_DECL([], [need_version], [0], [Do we need a version for libraries?])
+_LT_DECL([], [version_type], [0], [Library versioning type])
+_LT_DECL([], [runpath_var], [0],  [Shared library runtime path variable])
+_LT_DECL([], [shlibpath_var], [0],[Shared library path variable])
+_LT_DECL([], [shlibpath_overrides_runpath], [0],
+    [Is shlibpath searched before the hard-coded library search path?])
+_LT_DECL([], [libname_spec], [1], [Format of library name prefix])
+_LT_DECL([], [library_names_spec], [1],
+    [[List of archive names.  First name is the real one, the rest are links.
+    The last name is the one that the linker finds with -lNAME]])
+_LT_DECL([], [soname_spec], [1],
+    [[The coded name of the library, if different from the real name]])
+_LT_DECL([], [install_override_mode], [1],
+    [Permission mode override for installation of shared libraries])
+_LT_DECL([], [postinstall_cmds], [2],
+    [Command to use after installation of a shared archive])
+_LT_DECL([], [postuninstall_cmds], [2],
+    [Command to use after uninstallation of a shared archive])
+_LT_DECL([], [finish_cmds], [2],
+    [Commands used to finish a libtool library installation in a directory])
+_LT_DECL([], [finish_eval], [1],
+    [[As "finish_cmds", except a single script fragment to be evaled but
+    not shown]])
+_LT_DECL([], [hardcode_into_libs], [0],
+    [Whether we should hardcode library paths into libraries])
+_LT_DECL([], [sys_lib_search_path_spec], [2],
+    [Compile-time system search path for libraries])
+_LT_DECL([sys_lib_dlsearch_path_spec], [configure_time_dlsearch_path], [2],
+    [Detected run-time system search path for libraries])
+_LT_DECL([], [configure_time_lt_sys_library_path], [2],
+    [Explicit LT_SYS_LIBRARY_PATH set during ./configure time])
+])# _LT_SYS_DYNAMIC_LINKER
+
+
+# _LT_PATH_TOOL_PREFIX(TOOL)
+# --------------------------
+# find a file program that can recognize shared library
+AC_DEFUN([_LT_PATH_TOOL_PREFIX],
+[m4_require([_LT_DECL_EGREP])dnl
+AC_MSG_CHECKING([for $1])
+AC_CACHE_VAL(lt_cv_path_MAGIC_CMD,
+[case $MAGIC_CMD in
+[[\\/*] |  ?:[\\/]*])
+  lt_cv_path_MAGIC_CMD=$MAGIC_CMD # Let the user override the test with a path.
+  ;;
+*)
+  lt_save_MAGIC_CMD=$MAGIC_CMD
+  lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+dnl $ac_dummy forces splitting on constant user-supplied paths.
+dnl POSIX.2 word splitting is done only on the output of word expansions,
+dnl not every word.  This closes a longstanding sh security hole.
+  ac_dummy="m4_if([$2], , $PATH, [$2])"
+  for ac_dir in $ac_dummy; do
+    IFS=$lt_save_ifs
+    test -z "$ac_dir" && ac_dir=.
+    if test -f "$ac_dir/$1"; then
+      lt_cv_path_MAGIC_CMD=$ac_dir/"$1"
+      if test -n "$file_magic_test_file"; then
+	case $deplibs_check_method in
+	"file_magic "*)
+	  file_magic_regex=`expr "$deplibs_check_method" : "file_magic \(.*\)"`
+	  MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+	  if eval $file_magic_cmd \$file_magic_test_file 2> /dev/null |
+	    $EGREP "$file_magic_regex" > /dev/null; then
+	    :
+	  else
+	    cat <<_LT_EOF 1>&2
+
+*** Warning: the command libtool uses to detect shared libraries,
+*** $file_magic_cmd, produces output that libtool cannot recognize.
+*** The result is that libtool may fail to recognize shared libraries
+*** as such.  This will affect the creation of libtool libraries that
+*** depend on shared libraries, but programs linked with such libtool
+*** libraries will work regardless of this problem.  Nevertheless, you
+*** may want to report the problem to your system manager and/or to
+*** bug-libtool@gnu.org
+
+_LT_EOF
+	  fi ;;
+	esac
+      fi
+      break
+    fi
+  done
+  IFS=$lt_save_ifs
+  MAGIC_CMD=$lt_save_MAGIC_CMD
+  ;;
+esac])
+MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+if test -n "$MAGIC_CMD"; then
+  AC_MSG_RESULT($MAGIC_CMD)
+else
+  AC_MSG_RESULT(no)
+fi
+_LT_DECL([], [MAGIC_CMD], [0],
+	 [Used to examine libraries when file_magic_cmd begins with "file"])dnl
+])# _LT_PATH_TOOL_PREFIX
+
+# Old name:
+AU_ALIAS([AC_PATH_TOOL_PREFIX], [_LT_PATH_TOOL_PREFIX])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_PATH_TOOL_PREFIX], [])
+
+
+# _LT_PATH_MAGIC
+# --------------
+# find a file program that can recognize a shared library
+m4_defun([_LT_PATH_MAGIC],
+[_LT_PATH_TOOL_PREFIX(${ac_tool_prefix}file, /usr/bin$PATH_SEPARATOR$PATH)
+if test -z "$lt_cv_path_MAGIC_CMD"; then
+  if test -n "$ac_tool_prefix"; then
+    _LT_PATH_TOOL_PREFIX(file, /usr/bin$PATH_SEPARATOR$PATH)
+  else
+    MAGIC_CMD=:
+  fi
+fi
+])# _LT_PATH_MAGIC
+
+
+# LT_PATH_LD
+# ----------
+# find the pathname to the GNU or non-GNU linker
+AC_DEFUN([LT_PATH_LD],
+[AC_REQUIRE([AC_PROG_CC])dnl
+AC_REQUIRE([AC_CANONICAL_HOST])dnl
+AC_REQUIRE([AC_CANONICAL_BUILD])dnl
+m4_require([_LT_DECL_SED])dnl
+m4_require([_LT_DECL_EGREP])dnl
+m4_require([_LT_PROG_ECHO_BACKSLASH])dnl
+
+AC_ARG_WITH([gnu-ld],
+    [AS_HELP_STRING([--with-gnu-ld],
+	[assume the C compiler uses GNU ld @<:@default=no@:>@])],
+    [test no = "$withval" || with_gnu_ld=yes],
+    [with_gnu_ld=no])dnl
+
+ac_prog=ld
+if test yes = "$GCC"; then
+  # Check if gcc -print-prog-name=ld gives a path.
+  AC_MSG_CHECKING([for ld used by $CC])
+  case $host in
+  *-*-mingw*)
+    # gcc leaves a trailing carriage return, which upsets mingw
+    ac_prog=`($CC -print-prog-name=ld) 2>&5 | tr -d '\015'` ;;
+  *)
+    ac_prog=`($CC -print-prog-name=ld) 2>&5` ;;
+  esac
+  case $ac_prog in
+    # Accept absolute paths.
+    [[\\/]]* | ?:[[\\/]]*)
+      re_direlt='/[[^/]][[^/]]*/\.\./'
+      # Canonicalize the pathname of ld
+      ac_prog=`$ECHO "$ac_prog"| $SED 's%\\\\%/%g'`
+      while $ECHO "$ac_prog" | $GREP "$re_direlt" > /dev/null 2>&1; do
+	ac_prog=`$ECHO $ac_prog| $SED "s%$re_direlt%/%"`
+      done
+      test -z "$LD" && LD=$ac_prog
+      ;;
+  "")
+    # If it fails, then pretend we aren't using GCC.
+    ac_prog=ld
+    ;;
+  *)
+    # If it is relative, then search for the first ld in PATH.
+    with_gnu_ld=unknown
+    ;;
+  esac
+elif test yes = "$with_gnu_ld"; then
+  AC_MSG_CHECKING([for GNU ld])
+else
+  AC_MSG_CHECKING([for non-GNU ld])
+fi
+AC_CACHE_VAL(lt_cv_path_LD,
+[if test -z "$LD"; then
+  lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+  for ac_dir in $PATH; do
+    IFS=$lt_save_ifs
+    test -z "$ac_dir" && ac_dir=.
+    if test -f "$ac_dir/$ac_prog" || test -f "$ac_dir/$ac_prog$ac_exeext"; then
+      lt_cv_path_LD=$ac_dir/$ac_prog
+      # Check to see if the program is GNU ld.  I'd rather use --version,
+      # but apparently some variants of GNU ld only accept -v.
+      # Break only if it was the GNU/non-GNU ld that we prefer.
+      case `"$lt_cv_path_LD" -v 2>&1 </dev/null` in
+      *GNU* | *'with BFD'*)
+	test no != "$with_gnu_ld" && break
+	;;
+      *)
+	test yes != "$with_gnu_ld" && break
+	;;
+      esac
+    fi
+  done
+  IFS=$lt_save_ifs
+else
+  lt_cv_path_LD=$LD # Let the user override the test with a path.
+fi])
+LD=$lt_cv_path_LD
+if test -n "$LD"; then
+  AC_MSG_RESULT($LD)
+else
+  AC_MSG_RESULT(no)
+fi
+test -z "$LD" && AC_MSG_ERROR([no acceptable ld found in \$PATH])
+_LT_PATH_LD_GNU
+AC_SUBST([LD])
+
+_LT_TAGDECL([], [LD], [1], [The linker used to build libraries])
+])# LT_PATH_LD
+
+# Old names:
+AU_ALIAS([AM_PROG_LD], [LT_PATH_LD])
+AU_ALIAS([AC_PROG_LD], [LT_PATH_LD])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AM_PROG_LD], [])
+dnl AC_DEFUN([AC_PROG_LD], [])
+
+
+# _LT_PATH_LD_GNU
+#- --------------
+m4_defun([_LT_PATH_LD_GNU],
+[AC_CACHE_CHECK([if the linker ($LD) is GNU ld], lt_cv_prog_gnu_ld,
+[# I'd rather use --version here, but apparently some GNU lds only accept -v.
+case `$LD -v 2>&1 </dev/null` in
+*GNU* | *'with BFD'*)
+  lt_cv_prog_gnu_ld=yes
+  ;;
+*)
+  lt_cv_prog_gnu_ld=no
+  ;;
+esac])
+with_gnu_ld=$lt_cv_prog_gnu_ld
+])# _LT_PATH_LD_GNU
+
+
+# _LT_CMD_RELOAD
+# --------------
+# find reload flag for linker
+#   -- PORTME Some linkers may need a different reload flag.
+m4_defun([_LT_CMD_RELOAD],
+[AC_CACHE_CHECK([for $LD option to reload object files],
+  lt_cv_ld_reload_flag,
+  [lt_cv_ld_reload_flag='-r'])
+reload_flag=$lt_cv_ld_reload_flag
+case $reload_flag in
+"" | " "*) ;;
+*) reload_flag=" $reload_flag" ;;
+esac
+reload_cmds='$LD$reload_flag -o $output$reload_objs'
+case $host_os in
+  cygwin* | mingw* | pw32* | cegcc*)
+    if test yes != "$GCC"; then
+      reload_cmds=false
+    fi
+    ;;
+  darwin*)
+    if test yes = "$GCC"; then
+      reload_cmds='$LTCC $LTCFLAGS -nostdlib $wl-r -o $output$reload_objs'
+    else
+      reload_cmds='$LD$reload_flag -o $output$reload_objs'
+    fi
+    ;;
+esac
+_LT_TAGDECL([], [reload_flag], [1], [How to create reloadable object files])dnl
+_LT_TAGDECL([], [reload_cmds], [2])dnl
+])# _LT_CMD_RELOAD
+
+
+# _LT_PATH_DD
+# -----------
+# find a working dd
+m4_defun([_LT_PATH_DD],
+[AC_CACHE_CHECK([for a working dd], [ac_cv_path_lt_DD],
+[printf 0123456789abcdef0123456789abcdef >conftest.i
+cat conftest.i conftest.i >conftest2.i
+: ${lt_DD:=$DD}
+AC_PATH_PROGS_FEATURE_CHECK([lt_DD], [dd],
+[if "$ac_path_lt_DD" bs=32 count=1 <conftest2.i >conftest.out 2>/dev/null; then
+  cmp -s conftest.i conftest.out \
+  && ac_cv_path_lt_DD="$ac_path_lt_DD" ac_path_lt_DD_found=:
+fi])
+rm -f conftest.i conftest2.i conftest.out])
+])# _LT_PATH_DD
+
+
+# _LT_CMD_TRUNCATE
+# ----------------
+# find command to truncate a binary pipe
+m4_defun([_LT_CMD_TRUNCATE],
+[m4_require([_LT_PATH_DD])
+AC_CACHE_CHECK([how to truncate binary pipes], [lt_cv_truncate_bin],
+[printf 0123456789abcdef0123456789abcdef >conftest.i
+cat conftest.i conftest.i >conftest2.i
+lt_cv_truncate_bin=
+if "$ac_cv_path_lt_DD" bs=32 count=1 <conftest2.i >conftest.out 2>/dev/null; then
+  cmp -s conftest.i conftest.out \
+  && lt_cv_truncate_bin="$ac_cv_path_lt_DD bs=4096 count=1"
+fi
+rm -f conftest.i conftest2.i conftest.out
+test -z "$lt_cv_truncate_bin" && lt_cv_truncate_bin="$SED -e 4q"])
+_LT_DECL([lt_truncate_bin], [lt_cv_truncate_bin], [1],
+  [Command to truncate a binary pipe])
+])# _LT_CMD_TRUNCATE
+
+
+# _LT_CHECK_MAGIC_METHOD
+# ----------------------
+# how to check for library dependencies
+#  -- PORTME fill in with the dynamic library characteristics
+m4_defun([_LT_CHECK_MAGIC_METHOD],
+[m4_require([_LT_DECL_EGREP])
+m4_require([_LT_DECL_OBJDUMP])
+AC_CACHE_CHECK([how to recognize dependent libraries],
+lt_cv_deplibs_check_method,
+[lt_cv_file_magic_cmd='$MAGIC_CMD'
+lt_cv_file_magic_test_file=
+lt_cv_deplibs_check_method='unknown'
+# Need to set the preceding variable on all platforms that support
+# interlibrary dependencies.
+# 'none' -- dependencies not supported.
+# 'unknown' -- same as none, but documents that we really don't know.
+# 'pass_all' -- all dependencies passed with no checks.
+# 'test_compile' -- check by making test program.
+# 'file_magic [[regex]]' -- check by looking for files in library path
+# that responds to the $file_magic_cmd with a given extended regex.
+# If you have 'file' or equivalent on your system and you're not sure
+# whether 'pass_all' will *always* work, you probably want this one.
+
+case $host_os in
+aix[[4-9]]*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+beos*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+bsdi[[45]]*)
+  lt_cv_deplibs_check_method='file_magic ELF [[0-9]][[0-9]]*-bit [[ML]]SB (shared object|dynamic lib)'
+  lt_cv_file_magic_cmd='/usr/bin/file -L'
+  lt_cv_file_magic_test_file=/shlib/libc.so
+  ;;
+
+cygwin*)
+  # func_win32_libid is a shell function defined in ltmain.sh
+  lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
+  lt_cv_file_magic_cmd='func_win32_libid'
+  ;;
+
+mingw* | pw32*)
+  # Base MSYS/MinGW do not provide the 'file' command needed by
+  # func_win32_libid shell function, so use a weaker test based on 'objdump',
+  # unless we find 'file', for example because we are cross-compiling.
+  if ( file / ) >/dev/null 2>&1; then
+    lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
+    lt_cv_file_magic_cmd='func_win32_libid'
+  else
+    # Keep this pattern in sync with the one in func_win32_libid.
+    lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)'
+    lt_cv_file_magic_cmd='$OBJDUMP -f'
+  fi
+  ;;
+
+cegcc*)
+  # use the weaker test based on 'objdump'. See mingw*.
+  lt_cv_deplibs_check_method='file_magic file format pe-arm-.*little(.*architecture: arm)?'
+  lt_cv_file_magic_cmd='$OBJDUMP -f'
+  ;;
+
+darwin* | rhapsody*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+freebsd* | dragonfly*)
+  if echo __ELF__ | $CC -E - | $GREP __ELF__ > /dev/null; then
+    case $host_cpu in
+    i*86 )
+      # Not sure whether the presence of OpenBSD here was a mistake.
+      # Let's accept both of them until this is cleared up.
+      lt_cv_deplibs_check_method='file_magic (FreeBSD|OpenBSD|DragonFly)/i[[3-9]]86 (compact )?demand paged shared library'
+      lt_cv_file_magic_cmd=/usr/bin/file
+      lt_cv_file_magic_test_file=`echo /usr/lib/libc.so.*`
+      ;;
+    esac
+  else
+    lt_cv_deplibs_check_method=pass_all
+  fi
+  ;;
+
+haiku*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+hpux10.20* | hpux11*)
+  lt_cv_file_magic_cmd=/usr/bin/file
+  case $host_cpu in
+  ia64*)
+    lt_cv_deplibs_check_method='file_magic (s[[0-9]][[0-9]][[0-9]]|ELF-[[0-9]][[0-9]]) shared object file - IA64'
+    lt_cv_file_magic_test_file=/usr/lib/hpux32/libc.so
+    ;;
+  hppa*64*)
+    [lt_cv_deplibs_check_method='file_magic (s[0-9][0-9][0-9]|ELF[ -][0-9][0-9])(-bit)?( [LM]SB)? shared object( file)?[, -]* PA-RISC [0-9]\.[0-9]']
+    lt_cv_file_magic_test_file=/usr/lib/pa20_64/libc.sl
+    ;;
+  *)
+    lt_cv_deplibs_check_method='file_magic (s[[0-9]][[0-9]][[0-9]]|PA-RISC[[0-9]]\.[[0-9]]) shared library'
+    lt_cv_file_magic_test_file=/usr/lib/libc.sl
+    ;;
+  esac
+  ;;
+
+interix[[3-9]]*)
+  # PIC code is broken on Interix 3.x, that's why |\.a not |_pic\.a here
+  lt_cv_deplibs_check_method='match_pattern /lib[[^/]]+(\.so|\.a)$'
+  ;;
+
+irix5* | irix6* | nonstopux*)
+  case $LD in
+  *-32|*"-32 ") libmagic=32-bit;;
+  *-n32|*"-n32 ") libmagic=N32;;
+  *-64|*"-64 ") libmagic=64-bit;;
+  *) libmagic=never-match;;
+  esac
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+# This must be glibc/ELF.
+linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+netbsd*)
+  if echo __ELF__ | $CC -E - | $GREP __ELF__ > /dev/null; then
+    lt_cv_deplibs_check_method='match_pattern /lib[[^/]]+(\.so\.[[0-9]]+\.[[0-9]]+|_pic\.a)$'
+  else
+    lt_cv_deplibs_check_method='match_pattern /lib[[^/]]+(\.so|_pic\.a)$'
+  fi
+  ;;
+
+newos6*)
+  lt_cv_deplibs_check_method='file_magic ELF [[0-9]][[0-9]]*-bit [[ML]]SB (executable|dynamic lib)'
+  lt_cv_file_magic_cmd=/usr/bin/file
+  lt_cv_file_magic_test_file=/usr/lib/libnls.so
+  ;;
+
+*nto* | *qnx*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+openbsd* | bitrig*)
+  if test -z "`echo __ELF__ | $CC -E - | $GREP __ELF__`"; then
+    lt_cv_deplibs_check_method='match_pattern /lib[[^/]]+(\.so\.[[0-9]]+\.[[0-9]]+|\.so|_pic\.a)$'
+  else
+    lt_cv_deplibs_check_method='match_pattern /lib[[^/]]+(\.so\.[[0-9]]+\.[[0-9]]+|_pic\.a)$'
+  fi
+  ;;
+
+osf3* | osf4* | osf5*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+rdos*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+solaris*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX* | sysv4*uw2*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+sysv4 | sysv4.3*)
+  case $host_vendor in
+  motorola)
+    lt_cv_deplibs_check_method='file_magic ELF [[0-9]][[0-9]]*-bit [[ML]]SB (shared object|dynamic lib) M[[0-9]][[0-9]]* Version [[0-9]]'
+    lt_cv_file_magic_test_file=`echo /usr/lib/libc.so*`
+    ;;
+  ncr)
+    lt_cv_deplibs_check_method=pass_all
+    ;;
+  sequent)
+    lt_cv_file_magic_cmd='/bin/file'
+    lt_cv_deplibs_check_method='file_magic ELF [[0-9]][[0-9]]*-bit [[LM]]SB (shared object|dynamic lib )'
+    ;;
+  sni)
+    lt_cv_file_magic_cmd='/bin/file'
+    lt_cv_deplibs_check_method="file_magic ELF [[0-9]][[0-9]]*-bit [[LM]]SB dynamic lib"
+    lt_cv_file_magic_test_file=/lib/libc.so
+    ;;
+  siemens)
+    lt_cv_deplibs_check_method=pass_all
+    ;;
+  pc)
+    lt_cv_deplibs_check_method=pass_all
+    ;;
+  esac
+  ;;
+
+tpf*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+os2*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+esac
+])
+
+file_magic_glob=
+want_nocaseglob=no
+if test "$build" = "$host"; then
+  case $host_os in
+  mingw* | pw32*)
+    if ( shopt | grep nocaseglob ) >/dev/null 2>&1; then
+      want_nocaseglob=yes
+    else
+      file_magic_glob=`echo aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ | $SED -e "s/\(..\)/s\/[[\1]]\/[[\1]]\/g;/g"`
+    fi
+    ;;
+  esac
+fi
+
+file_magic_cmd=$lt_cv_file_magic_cmd
+deplibs_check_method=$lt_cv_deplibs_check_method
+test -z "$deplibs_check_method" && deplibs_check_method=unknown
+
+_LT_DECL([], [deplibs_check_method], [1],
+    [Method to check whether dependent libraries are shared objects])
+_LT_DECL([], [file_magic_cmd], [1],
+    [Command to use when deplibs_check_method = "file_magic"])
+_LT_DECL([], [file_magic_glob], [1],
+    [How to find potential files when deplibs_check_method = "file_magic"])
+_LT_DECL([], [want_nocaseglob], [1],
+    [Find potential files using nocaseglob when deplibs_check_method = "file_magic"])
+])# _LT_CHECK_MAGIC_METHOD
+
+
+# LT_PATH_NM
+# ----------
+# find the pathname to a BSD- or MS-compatible name lister
+AC_DEFUN([LT_PATH_NM],
+[AC_REQUIRE([AC_PROG_CC])dnl
+AC_CACHE_CHECK([for BSD- or MS-compatible name lister (nm)], lt_cv_path_NM,
+[if test -n "$NM"; then
+  # Let the user override the test.
+  lt_cv_path_NM=$NM
+else
+  lt_nm_to_check=${ac_tool_prefix}nm
+  if test -n "$ac_tool_prefix" && test "$build" = "$host"; then
+    lt_nm_to_check="$lt_nm_to_check nm"
+  fi
+  for lt_tmp_nm in $lt_nm_to_check; do
+    lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+    for ac_dir in $PATH /usr/ccs/bin/elf /usr/ccs/bin /usr/ucb /bin; do
+      IFS=$lt_save_ifs
+      test -z "$ac_dir" && ac_dir=.
+      tmp_nm=$ac_dir/$lt_tmp_nm
+      if test -f "$tmp_nm" || test -f "$tmp_nm$ac_exeext"; then
+	# Check to see if the nm accepts a BSD-compat flag.
+	# Adding the 'sed 1q' prevents false positives on HP-UX, which says:
+	#   nm: unknown option "B" ignored
+	# Tru64's nm complains that /dev/null is an invalid object file
+	# MSYS converts /dev/null to NUL, MinGW nm treats NUL as empty
+	case $build_os in
+	mingw*) lt_bad_file=conftest.nm/nofile ;;
+	*) lt_bad_file=/dev/null ;;
+	esac
+	case `"$tmp_nm" -B $lt_bad_file 2>&1 | sed '1q'` in
+	*$lt_bad_file* | *'Invalid file or object type'*)
+	  lt_cv_path_NM="$tmp_nm -B"
+	  break 2
+	  ;;
+	*)
+	  case `"$tmp_nm" -p /dev/null 2>&1 | sed '1q'` in
+	  */dev/null*)
+	    lt_cv_path_NM="$tmp_nm -p"
+	    break 2
+	    ;;
+	  *)
+	    lt_cv_path_NM=${lt_cv_path_NM="$tmp_nm"} # keep the first match, but
+	    continue # so that we can try to find one that supports BSD flags
+	    ;;
+	  esac
+	  ;;
+	esac
+      fi
+    done
+    IFS=$lt_save_ifs
+  done
+  : ${lt_cv_path_NM=no}
+fi])
+if test no != "$lt_cv_path_NM"; then
+  NM=$lt_cv_path_NM
+else
+  # Didn't find any BSD compatible name lister, look for dumpbin.
+  if test -n "$DUMPBIN"; then :
+    # Let the user override the test.
+  else
+    AC_CHECK_TOOLS(DUMPBIN, [dumpbin "link -dump"], :)
+    case `$DUMPBIN -symbols -headers /dev/null 2>&1 | sed '1q'` in
+    *COFF*)
+      DUMPBIN="$DUMPBIN -symbols -headers"
+      ;;
+    *)
+      DUMPBIN=:
+      ;;
+    esac
+  fi
+  AC_SUBST([DUMPBIN])
+  if test : != "$DUMPBIN"; then
+    NM=$DUMPBIN
+  fi
+fi
+test -z "$NM" && NM=nm
+AC_SUBST([NM])
+_LT_DECL([], [NM], [1], [A BSD- or MS-compatible name lister])dnl
+
+AC_CACHE_CHECK([the name lister ($NM) interface], [lt_cv_nm_interface],
+  [lt_cv_nm_interface="BSD nm"
+  echo "int some_variable = 0;" > conftest.$ac_ext
+  (eval echo "\"\$as_me:$LINENO: $ac_compile\"" >&AS_MESSAGE_LOG_FD)
+  (eval "$ac_compile" 2>conftest.err)
+  cat conftest.err >&AS_MESSAGE_LOG_FD
+  (eval echo "\"\$as_me:$LINENO: $NM \\\"conftest.$ac_objext\\\"\"" >&AS_MESSAGE_LOG_FD)
+  (eval "$NM \"conftest.$ac_objext\"" 2>conftest.err > conftest.out)
+  cat conftest.err >&AS_MESSAGE_LOG_FD
+  (eval echo "\"\$as_me:$LINENO: output\"" >&AS_MESSAGE_LOG_FD)
+  cat conftest.out >&AS_MESSAGE_LOG_FD
+  if $GREP 'External.*some_variable' conftest.out > /dev/null; then
+    lt_cv_nm_interface="MS dumpbin"
+  fi
+  rm -f conftest*])
+])# LT_PATH_NM
+
+# Old names:
+AU_ALIAS([AM_PROG_NM], [LT_PATH_NM])
+AU_ALIAS([AC_PROG_NM], [LT_PATH_NM])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AM_PROG_NM], [])
+dnl AC_DEFUN([AC_PROG_NM], [])
+
+# _LT_CHECK_SHAREDLIB_FROM_LINKLIB
+# --------------------------------
+# how to determine the name of the shared library
+# associated with a specific link library.
+#  -- PORTME fill in with the dynamic library characteristics
+m4_defun([_LT_CHECK_SHAREDLIB_FROM_LINKLIB],
+[m4_require([_LT_DECL_EGREP])
+m4_require([_LT_DECL_OBJDUMP])
+m4_require([_LT_DECL_DLLTOOL])
+AC_CACHE_CHECK([how to associate runtime and link libraries],
+lt_cv_sharedlib_from_linklib_cmd,
+[lt_cv_sharedlib_from_linklib_cmd='unknown'
+
+case $host_os in
+cygwin* | mingw* | pw32* | cegcc*)
+  # two different shell functions defined in ltmain.sh;
+  # decide which one to use based on capabilities of $DLLTOOL
+  case `$DLLTOOL --help 2>&1` in
+  *--identify-strict*)
+    lt_cv_sharedlib_from_linklib_cmd=func_cygming_dll_for_implib
+    ;;
+  *)
+    lt_cv_sharedlib_from_linklib_cmd=func_cygming_dll_for_implib_fallback
+    ;;
+  esac
+  ;;
+*)
+  # fallback: assume linklib IS sharedlib
+  lt_cv_sharedlib_from_linklib_cmd=$ECHO
+  ;;
+esac
+])
+sharedlib_from_linklib_cmd=$lt_cv_sharedlib_from_linklib_cmd
+test -z "$sharedlib_from_linklib_cmd" && sharedlib_from_linklib_cmd=$ECHO
+
+_LT_DECL([], [sharedlib_from_linklib_cmd], [1],
+    [Command to associate shared and link libraries])
+])# _LT_CHECK_SHAREDLIB_FROM_LINKLIB
+
+
+# _LT_PATH_MANIFEST_TOOL
+# ----------------------
+# locate the manifest tool
+m4_defun([_LT_PATH_MANIFEST_TOOL],
+[AC_CHECK_TOOL(MANIFEST_TOOL, mt, :)
+test -z "$MANIFEST_TOOL" && MANIFEST_TOOL=mt
+AC_CACHE_CHECK([if $MANIFEST_TOOL is a manifest tool], [lt_cv_path_mainfest_tool],
+  [lt_cv_path_mainfest_tool=no
+  echo "$as_me:$LINENO: $MANIFEST_TOOL '-?'" >&AS_MESSAGE_LOG_FD
+  $MANIFEST_TOOL '-?' 2>conftest.err > conftest.out
+  cat conftest.err >&AS_MESSAGE_LOG_FD
+  if $GREP 'Manifest Tool' conftest.out > /dev/null; then
+    lt_cv_path_mainfest_tool=yes
+  fi
+  rm -f conftest*])
+if test yes != "$lt_cv_path_mainfest_tool"; then
+  MANIFEST_TOOL=:
+fi
+_LT_DECL([], [MANIFEST_TOOL], [1], [Manifest tool])dnl
+])# _LT_PATH_MANIFEST_TOOL
+
+
+# _LT_DLL_DEF_P([FILE])
+# ---------------------
+# True iff FILE is a Windows DLL '.def' file.
+# Keep in sync with func_dll_def_p in the libtool script
+AC_DEFUN([_LT_DLL_DEF_P],
+[dnl
+  test DEF = "`$SED -n dnl
+    -e '\''s/^[[	 ]]*//'\'' dnl Strip leading whitespace
+    -e '\''/^\(;.*\)*$/d'\'' dnl      Delete empty lines and comments
+    -e '\''s/^\(EXPORTS\|LIBRARY\)\([[	 ]].*\)*$/DEF/p'\'' dnl
+    -e q dnl                          Only consider the first "real" line
+    $1`" dnl
+])# _LT_DLL_DEF_P
+
+
+# LT_LIB_M
+# --------
+# check for math library
+AC_DEFUN([LT_LIB_M],
+[AC_REQUIRE([AC_CANONICAL_HOST])dnl
+LIBM=
+case $host in
+*-*-beos* | *-*-cegcc* | *-*-cygwin* | *-*-haiku* | *-*-pw32* | *-*-darwin*)
+  # These system don't have libm, or don't need it
+  ;;
+*-ncr-sysv4.3*)
+  AC_CHECK_LIB(mw, _mwvalidcheckl, LIBM=-lmw)
+  AC_CHECK_LIB(m, cos, LIBM="$LIBM -lm")
+  ;;
+*)
+  AC_CHECK_LIB(m, cos, LIBM=-lm)
+  ;;
+esac
+AC_SUBST([LIBM])
+])# LT_LIB_M
+
+# Old name:
+AU_ALIAS([AC_CHECK_LIBM], [LT_LIB_M])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_CHECK_LIBM], [])
+
+
+# _LT_COMPILER_NO_RTTI([TAGNAME])
+# -------------------------------
+m4_defun([_LT_COMPILER_NO_RTTI],
+[m4_require([_LT_TAG_COMPILER])dnl
+
+_LT_TAGVAR(lt_prog_compiler_no_builtin_flag, $1)=
+
+if test yes = "$GCC"; then
+  case $cc_basename in
+  nvcc*)
+    _LT_TAGVAR(lt_prog_compiler_no_builtin_flag, $1)=' -Xcompiler -fno-builtin' ;;
+  *)
+    _LT_TAGVAR(lt_prog_compiler_no_builtin_flag, $1)=' -fno-builtin' ;;
+  esac
+
+  _LT_COMPILER_OPTION([if $compiler supports -fno-rtti -fno-exceptions],
+    lt_cv_prog_compiler_rtti_exceptions,
+    [-fno-rtti -fno-exceptions], [],
+    [_LT_TAGVAR(lt_prog_compiler_no_builtin_flag, $1)="$_LT_TAGVAR(lt_prog_compiler_no_builtin_flag, $1) -fno-rtti -fno-exceptions"])
+fi
+_LT_TAGDECL([no_builtin_flag], [lt_prog_compiler_no_builtin_flag], [1],
+	[Compiler flag to turn off builtin functions])
+])# _LT_COMPILER_NO_RTTI
+
+
+# _LT_CMD_GLOBAL_SYMBOLS
+# ----------------------
+m4_defun([_LT_CMD_GLOBAL_SYMBOLS],
+[AC_REQUIRE([AC_CANONICAL_HOST])dnl
+AC_REQUIRE([AC_PROG_CC])dnl
+AC_REQUIRE([AC_PROG_AWK])dnl
+AC_REQUIRE([LT_PATH_NM])dnl
+AC_REQUIRE([LT_PATH_LD])dnl
+m4_require([_LT_DECL_SED])dnl
+m4_require([_LT_DECL_EGREP])dnl
+m4_require([_LT_TAG_COMPILER])dnl
+
+# Check for command to grab the raw symbol name followed by C symbol from nm.
+AC_MSG_CHECKING([command to parse $NM output from $compiler object])
+AC_CACHE_VAL([lt_cv_sys_global_symbol_pipe],
+[
+# These are sane defaults that work on at least a few old systems.
+# [They come from Ultrix.  What could be older than Ultrix?!! ;)]
+
+# Character class describing NM global symbol codes.
+symcode='[[BCDEGRST]]'
+
+# Regexp to match symbols that can be accessed directly from C.
+sympat='\([[_A-Za-z]][[_A-Za-z0-9]]*\)'
+
+# Define system-specific variables.
+case $host_os in
+aix*)
+  symcode='[[BCDT]]'
+  ;;
+cygwin* | mingw* | pw32* | cegcc*)
+  symcode='[[ABCDGISTW]]'
+  ;;
+hpux*)
+  if test ia64 = "$host_cpu"; then
+    symcode='[[ABCDEGRST]]'
+  fi
+  ;;
+irix* | nonstopux*)
+  symcode='[[BCDEGRST]]'
+  ;;
+osf*)
+  symcode='[[BCDEGQRST]]'
+  ;;
+solaris*)
+  symcode='[[BDRT]]'
+  ;;
+sco3.2v5*)
+  symcode='[[DT]]'
+  ;;
+sysv4.2uw2*)
+  symcode='[[DT]]'
+  ;;
+sysv5* | sco5v6* | unixware* | OpenUNIX*)
+  symcode='[[ABDT]]'
+  ;;
+sysv4)
+  symcode='[[DFNSTU]]'
+  ;;
+esac
+
+# If we're using GNU nm, then use its standard symbol codes.
+case `$NM -V 2>&1` in
+*GNU* | *'with BFD'*)
+  symcode='[[ABCDGIRSTW]]' ;;
+esac
+
+if test "$lt_cv_nm_interface" = "MS dumpbin"; then
+  # Gets list of data symbols to import.
+  lt_cv_sys_global_symbol_to_import="sed -n -e 's/^I .* \(.*\)$/\1/p'"
+  # Adjust the below global symbol transforms to fixup imported variables.
+  lt_cdecl_hook=" -e 's/^I .* \(.*\)$/extern __declspec(dllimport) char \1;/p'"
+  lt_c_name_hook=" -e 's/^I .* \(.*\)$/  {\"\1\", (void *) 0},/p'"
+  lt_c_name_lib_hook="\
+  -e 's/^I .* \(lib.*\)$/  {\"\1\", (void *) 0},/p'\
+  -e 's/^I .* \(.*\)$/  {\"lib\1\", (void *) 0},/p'"
+else
+  # Disable hooks by default.
+  lt_cv_sys_global_symbol_to_import=
+  lt_cdecl_hook=
+  lt_c_name_hook=
+  lt_c_name_lib_hook=
+fi
+
+# Transform an extracted symbol line into a proper C declaration.
+# Some systems (esp. on ia64) link data and code symbols differently,
+# so use this general approach.
+lt_cv_sys_global_symbol_to_cdecl="sed -n"\
+$lt_cdecl_hook\
+" -e 's/^T .* \(.*\)$/extern int \1();/p'"\
+" -e 's/^$symcode$symcode* .* \(.*\)$/extern char \1;/p'"
+
+# Transform an extracted symbol line into symbol name and symbol address
+lt_cv_sys_global_symbol_to_c_name_address="sed -n"\
+$lt_c_name_hook\
+" -e 's/^: \(.*\) .*$/  {\"\1\", (void *) 0},/p'"\
+" -e 's/^$symcode$symcode* .* \(.*\)$/  {\"\1\", (void *) \&\1},/p'"
+
+# Transform an extracted symbol line into symbol name with lib prefix and
+# symbol address.
+lt_cv_sys_global_symbol_to_c_name_address_lib_prefix="sed -n"\
+$lt_c_name_lib_hook\
+" -e 's/^: \(.*\) .*$/  {\"\1\", (void *) 0},/p'"\
+" -e 's/^$symcode$symcode* .* \(lib.*\)$/  {\"\1\", (void *) \&\1},/p'"\
+" -e 's/^$symcode$symcode* .* \(.*\)$/  {\"lib\1\", (void *) \&\1},/p'"
+
+# Handle CRLF in mingw tool chain
+opt_cr=
+case $build_os in
+mingw*)
+  opt_cr=`$ECHO 'x\{0,1\}' | tr x '\015'` # option cr in regexp
+  ;;
+esac
+
+# Try without a prefix underscore, then with it.
+for ac_symprfx in "" "_"; do
+
+  # Transform symcode, sympat, and symprfx into a raw symbol and a C symbol.
+  symxfrm="\\1 $ac_symprfx\\2 \\2"
+
+  # Write the raw and C identifiers.
+  if test "$lt_cv_nm_interface" = "MS dumpbin"; then
+    # Fake it for dumpbin and say T for any non-static function,
+    # D for any global variable and I for any imported variable.
+    # Also find C++ and __fastcall symbols from MSVC++,
+    # which start with @ or ?.
+    lt_cv_sys_global_symbol_pipe="$AWK ['"\
+"     {last_section=section; section=\$ 3};"\
+"     /^COFF SYMBOL TABLE/{for(i in hide) delete hide[i]};"\
+"     /Section length .*#relocs.*(pick any)/{hide[last_section]=1};"\
+"     /^ *Symbol name *: /{split(\$ 0,sn,\":\"); si=substr(sn[2],2)};"\
+"     /^ *Type *: code/{print \"T\",si,substr(si,length(prfx))};"\
+"     /^ *Type *: data/{print \"I\",si,substr(si,length(prfx))};"\
+"     \$ 0!~/External *\|/{next};"\
+"     / 0+ UNDEF /{next}; / UNDEF \([^|]\)*()/{next};"\
+"     {if(hide[section]) next};"\
+"     {f=\"D\"}; \$ 0~/\(\).*\|/{f=\"T\"};"\
+"     {split(\$ 0,a,/\||\r/); split(a[2],s)};"\
+"     s[1]~/^[@?]/{print f,s[1],s[1]; next};"\
+"     s[1]~prfx {split(s[1],t,\"@\"); print f,t[1],substr(t[1],length(prfx))}"\
+"     ' prfx=^$ac_symprfx]"
+  else
+    lt_cv_sys_global_symbol_pipe="sed -n -e 's/^.*[[	 ]]\($symcode$symcode*\)[[	 ]][[	 ]]*$ac_symprfx$sympat$opt_cr$/$symxfrm/p'"
+  fi
+  lt_cv_sys_global_symbol_pipe="$lt_cv_sys_global_symbol_pipe | sed '/ __gnu_lto/d'"
+
+  # Check to see that the pipe works correctly.
+  pipe_works=no
+
+  rm -f conftest*
+  cat > conftest.$ac_ext <<_LT_EOF
+#ifdef __cplusplus
+extern "C" {
+#endif
+char nm_test_var;
+void nm_test_func(void);
+void nm_test_func(void){}
+#ifdef __cplusplus
+}
+#endif
+int main(){nm_test_var='a';nm_test_func();return(0);}
+_LT_EOF
+
+  if AC_TRY_EVAL(ac_compile); then
+    # Now try to grab the symbols.
+    nlist=conftest.nm
+    if AC_TRY_EVAL(NM conftest.$ac_objext \| "$lt_cv_sys_global_symbol_pipe" \> $nlist) && test -s "$nlist"; then
+      # Try sorting and uniquifying the output.
+      if sort "$nlist" | uniq > "$nlist"T; then
+	mv -f "$nlist"T "$nlist"
+      else
+	rm -f "$nlist"T
+      fi
+
+      # Make sure that we snagged all the symbols we need.
+      if $GREP ' nm_test_var$' "$nlist" >/dev/null; then
+	if $GREP ' nm_test_func$' "$nlist" >/dev/null; then
+	  cat <<_LT_EOF > conftest.$ac_ext
+/* Keep this code in sync between libtool.m4, ltmain, lt_system.h, and tests.  */
+#if defined _WIN32 || defined __CYGWIN__ || defined _WIN32_WCE
+/* DATA imports from DLLs on WIN32 can't be const, because runtime
+   relocations are performed -- see ld's documentation on pseudo-relocs.  */
+# define LT@&t@_DLSYM_CONST
+#elif defined __osf__
+/* This system does not cope well with relocations in const data.  */
+# define LT@&t@_DLSYM_CONST
+#else
+# define LT@&t@_DLSYM_CONST const
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+_LT_EOF
+	  # Now generate the symbol file.
+	  eval "$lt_cv_sys_global_symbol_to_cdecl"' < "$nlist" | $GREP -v main >> conftest.$ac_ext'
+
+	  cat <<_LT_EOF >> conftest.$ac_ext
+
+/* The mapping between symbol names and symbols.  */
+LT@&t@_DLSYM_CONST struct {
+  const char *name;
+  void       *address;
+}
+lt__PROGRAM__LTX_preloaded_symbols[[]] =
+{
+  { "@PROGRAM@", (void *) 0 },
+_LT_EOF
+	  $SED "s/^$symcode$symcode* .* \(.*\)$/  {\"\1\", (void *) \&\1},/" < "$nlist" | $GREP -v main >> conftest.$ac_ext
+	  cat <<\_LT_EOF >> conftest.$ac_ext
+  {0, (void *) 0}
+};
+
+/* This works around a problem in FreeBSD linker */
+#ifdef FREEBSD_WORKAROUND
+static const void *lt_preloaded_setup() {
+  return lt__PROGRAM__LTX_preloaded_symbols;
+}
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+_LT_EOF
+	  # Now try linking the two files.
+	  mv conftest.$ac_objext conftstm.$ac_objext
+	  lt_globsym_save_LIBS=$LIBS
+	  lt_globsym_save_CFLAGS=$CFLAGS
+	  LIBS=conftstm.$ac_objext
+	  CFLAGS="$CFLAGS$_LT_TAGVAR(lt_prog_compiler_no_builtin_flag, $1)"
+	  if AC_TRY_EVAL(ac_link) && test -s conftest$ac_exeext; then
+	    pipe_works=yes
+	  fi
+	  LIBS=$lt_globsym_save_LIBS
+	  CFLAGS=$lt_globsym_save_CFLAGS
+	else
+	  echo "cannot find nm_test_func in $nlist" >&AS_MESSAGE_LOG_FD
+	fi
+      else
+	echo "cannot find nm_test_var in $nlist" >&AS_MESSAGE_LOG_FD
+      fi
+    else
+      echo "cannot run $lt_cv_sys_global_symbol_pipe" >&AS_MESSAGE_LOG_FD
+    fi
+  else
+    echo "$progname: failed program was:" >&AS_MESSAGE_LOG_FD
+    cat conftest.$ac_ext >&5
+  fi
+  rm -rf conftest* conftst*
+
+  # Do not use the global_symbol_pipe unless it works.
+  if test yes = "$pipe_works"; then
+    break
+  else
+    lt_cv_sys_global_symbol_pipe=
+  fi
+done
+])
+if test -z "$lt_cv_sys_global_symbol_pipe"; then
+  lt_cv_sys_global_symbol_to_cdecl=
+fi
+if test -z "$lt_cv_sys_global_symbol_pipe$lt_cv_sys_global_symbol_to_cdecl"; then
+  AC_MSG_RESULT(failed)
+else
+  AC_MSG_RESULT(ok)
+fi
+
+# Response file support.
+if test "$lt_cv_nm_interface" = "MS dumpbin"; then
+  nm_file_list_spec='@'
+elif $NM --help 2>/dev/null | grep '[[@]]FILE' >/dev/null; then
+  nm_file_list_spec='@'
+fi
+
+_LT_DECL([global_symbol_pipe], [lt_cv_sys_global_symbol_pipe], [1],
+    [Take the output of nm and produce a listing of raw symbols and C names])
+_LT_DECL([global_symbol_to_cdecl], [lt_cv_sys_global_symbol_to_cdecl], [1],
+    [Transform the output of nm in a proper C declaration])
+_LT_DECL([global_symbol_to_import], [lt_cv_sys_global_symbol_to_import], [1],
+    [Transform the output of nm into a list of symbols to manually relocate])
+_LT_DECL([global_symbol_to_c_name_address],
+    [lt_cv_sys_global_symbol_to_c_name_address], [1],
+    [Transform the output of nm in a C name address pair])
+_LT_DECL([global_symbol_to_c_name_address_lib_prefix],
+    [lt_cv_sys_global_symbol_to_c_name_address_lib_prefix], [1],
+    [Transform the output of nm in a C name address pair when lib prefix is needed])
+_LT_DECL([nm_interface], [lt_cv_nm_interface], [1],
+    [The name lister interface])
+_LT_DECL([], [nm_file_list_spec], [1],
+    [Specify filename containing input files for $NM])
+]) # _LT_CMD_GLOBAL_SYMBOLS
+
+
+# _LT_COMPILER_PIC([TAGNAME])
+# ---------------------------
+m4_defun([_LT_COMPILER_PIC],
+[m4_require([_LT_TAG_COMPILER])dnl
+_LT_TAGVAR(lt_prog_compiler_wl, $1)=
+_LT_TAGVAR(lt_prog_compiler_pic, $1)=
+_LT_TAGVAR(lt_prog_compiler_static, $1)=
+
+m4_if([$1], [CXX], [
+  # C++ specific cases for pic, static, wl, etc.
+  if test yes = "$GXX"; then
+    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+    _LT_TAGVAR(lt_prog_compiler_static, $1)='-static'
+
+    case $host_os in
+    aix*)
+      # All AIX code is PIC.
+      if test ia64 = "$host_cpu"; then
+	# AIX 5 now supports IA64 processor
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      fi
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+        ;;
+      m68k)
+            # FIXME: we need at least 68020 code to build shared libraries, but
+            # adding the '-m68020' flag to GCC prevents building anything better,
+            # like '-m68040'.
+            _LT_TAGVAR(lt_prog_compiler_pic, $1)='-m68020 -resident32 -malways-restore-a4'
+        ;;
+      esac
+      ;;
+
+    beos* | irix5* | irix6* | nonstopux* | osf3* | osf4* | osf5*)
+      # PIC is the default for these OSes.
+      ;;
+    mingw* | cygwin* | os2* | pw32* | cegcc*)
+      # This hack is so that the source file can tell whether it is being
+      # built for inclusion in a dll (and should export symbols for example).
+      # Although the cygwin gcc ignores -fPIC, still need this for old-style
+      # (--disable-auto-import) libraries
+      m4_if([$1], [GCJ], [],
+	[_LT_TAGVAR(lt_prog_compiler_pic, $1)='-DDLL_EXPORT'])
+      case $host_os in
+      os2*)
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='$wl-static'
+	;;
+      esac
+      ;;
+    darwin* | rhapsody*)
+      # PIC is the default on this platform
+      # Common symbols not allowed in MH_DYLIB files
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fno-common'
+      ;;
+    *djgpp*)
+      # DJGPP does not support shared libraries at all
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)=
+      ;;
+    haiku*)
+      # PIC is the default for Haiku.
+      # The "-static" flag exists, but is broken.
+      _LT_TAGVAR(lt_prog_compiler_static, $1)=
+      ;;
+    interix[[3-9]]*)
+      # Interix 3.x gcc -fpic/-fPIC options generate broken code.
+      # Instead, we relocate shared libraries at runtime.
+      ;;
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)=-Kconform_pic
+      fi
+      ;;
+    hpux*)
+      # PIC is the default for 64-bit PA HP-UX, but not for 32-bit
+      # PA HP-UX.  On IA64 HP-UX, PIC is the default but the pic flag
+      # sets the default TLS model and affects inlining.
+      case $host_cpu in
+      hppa*64*)
+	;;
+      *)
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+	;;
+      esac
+      ;;
+    *qnx* | *nto*)
+      # QNX uses GNU C++, but need to define -shared option too, otherwise
+      # it will coredump.
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC -shared'
+      ;;
+    *)
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+      ;;
+    esac
+  else
+    case $host_os in
+      aix[[4-9]]*)
+	# All AIX code is PIC.
+	if test ia64 = "$host_cpu"; then
+	  # AIX 5 now supports IA64 processor
+	  _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	else
+	  _LT_TAGVAR(lt_prog_compiler_static, $1)='-bnso -bI:/lib/syscalls.exp'
+	fi
+	;;
+      chorus*)
+	case $cc_basename in
+	cxch68*)
+	  # Green Hills C++ Compiler
+	  # _LT_TAGVAR(lt_prog_compiler_static, $1)="--no_auto_instantiation -u __main -u __premain -u _abort -r $COOL_DIR/lib/libOrb.a $MVME_DIR/lib/CC/libC.a $MVME_DIR/lib/classix/libcx.s.a"
+	  ;;
+	esac
+	;;
+      mingw* | cygwin* | os2* | pw32* | cegcc*)
+	# This hack is so that the source file can tell whether it is being
+	# built for inclusion in a dll (and should export symbols for example).
+	m4_if([$1], [GCJ], [],
+	  [_LT_TAGVAR(lt_prog_compiler_pic, $1)='-DDLL_EXPORT'])
+	;;
+      dgux*)
+	case $cc_basename in
+	  ec++*)
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	    ;;
+	  ghcx*)
+	    # Green Hills C++ Compiler
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-pic'
+	    ;;
+	  *)
+	    ;;
+	esac
+	;;
+      freebsd* | dragonfly*)
+	# FreeBSD uses GNU C++
+	;;
+      hpux9* | hpux10* | hpux11*)
+	case $cc_basename in
+	  CC*)
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='$wl-a ${wl}archive'
+	    if test ia64 != "$host_cpu"; then
+	      _LT_TAGVAR(lt_prog_compiler_pic, $1)='+Z'
+	    fi
+	    ;;
+	  aCC*)
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='$wl-a ${wl}archive'
+	    case $host_cpu in
+	    hppa*64*|ia64*)
+	      # +Z the default
+	      ;;
+	    *)
+	      _LT_TAGVAR(lt_prog_compiler_pic, $1)='+Z'
+	      ;;
+	    esac
+	    ;;
+	  *)
+	    ;;
+	esac
+	;;
+      interix*)
+	# This is c89, which is MS Visual C++ (no shared libs)
+	# Anyone wants to do a port?
+	;;
+      irix5* | irix6* | nonstopux*)
+	case $cc_basename in
+	  CC*)
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-non_shared'
+	    # CC pic flag -KPIC is the default.
+	    ;;
+	  *)
+	    ;;
+	esac
+	;;
+      linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+	case $cc_basename in
+	  KCC*)
+	    # KAI C++ Compiler
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='--backend -Wl,'
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+	    ;;
+	  ecpc* )
+	    # old Intel C++ for x86_64, which still supported -KPIC.
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-static'
+	    ;;
+	  icpc* )
+	    # Intel C++, used to be incompatible with GCC.
+	    # ICC 10 doesn't accept -KPIC any more.
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-static'
+	    ;;
+	  pgCC* | pgcpp*)
+	    # Portland Group C++ compiler
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fpic'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	    ;;
+	  cxx*)
+	    # Compaq C++
+	    # Make sure the PIC flag is empty.  It appears that all Alpha
+	    # Linux and Compaq Tru64 Unix objects are PIC.
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)=
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-non_shared'
+	    ;;
+	  xlc* | xlC* | bgxl[[cC]]* | mpixl[[cC]]*)
+	    # IBM XL 8.0, 9.0 on PPC and BlueGene
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-qpic'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-qstaticlink'
+	    ;;
+	  *)
+	    case `$CC -V 2>&1 | sed 5q` in
+	    *Sun\ C*)
+	      # Sun C++ 5.9
+	      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	      _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Qoption ld '
+	      ;;
+	    esac
+	    ;;
+	esac
+	;;
+      lynxos*)
+	;;
+      m88k*)
+	;;
+      mvs*)
+	case $cc_basename in
+	  cxx*)
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-W c,exportall'
+	    ;;
+	  *)
+	    ;;
+	esac
+	;;
+      netbsd*)
+	;;
+      *qnx* | *nto*)
+        # QNX uses GNU C++, but need to define -shared option too, otherwise
+        # it will coredump.
+        _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC -shared'
+        ;;
+      osf3* | osf4* | osf5*)
+	case $cc_basename in
+	  KCC*)
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='--backend -Wl,'
+	    ;;
+	  RCC*)
+	    # Rational C++ 2.4.1
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-pic'
+	    ;;
+	  cxx*)
+	    # Digital/Compaq C++
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	    # Make sure the PIC flag is empty.  It appears that all Alpha
+	    # Linux and Compaq Tru64 Unix objects are PIC.
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)=
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-non_shared'
+	    ;;
+	  *)
+	    ;;
+	esac
+	;;
+      psos*)
+	;;
+      solaris*)
+	case $cc_basename in
+	  CC* | sunCC*)
+	    # Sun C++ 4.2, 5.x and Centerline C++
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Qoption ld '
+	    ;;
+	  gcx*)
+	    # Green Hills C++ Compiler
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-PIC'
+	    ;;
+	  *)
+	    ;;
+	esac
+	;;
+      sunos4*)
+	case $cc_basename in
+	  CC*)
+	    # Sun C++ 4.x
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-pic'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	    ;;
+	  lcc*)
+	    # Lucid
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-pic'
+	    ;;
+	  *)
+	    ;;
+	esac
+	;;
+      sysv5* | unixware* | sco3.2v5* | sco5v6* | OpenUNIX*)
+	case $cc_basename in
+	  CC*)
+	    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	    _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	    ;;
+	esac
+	;;
+      tandem*)
+	case $cc_basename in
+	  NCC*)
+	    # NonStop-UX NCC 3.20
+	    _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	    ;;
+	  *)
+	    ;;
+	esac
+	;;
+      vxworks*)
+	;;
+      *)
+	_LT_TAGVAR(lt_prog_compiler_can_build_shared, $1)=no
+	;;
+    esac
+  fi
+],
+[
+  if test yes = "$GCC"; then
+    _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+    _LT_TAGVAR(lt_prog_compiler_static, $1)='-static'
+
+    case $host_os in
+      aix*)
+      # All AIX code is PIC.
+      if test ia64 = "$host_cpu"; then
+	# AIX 5 now supports IA64 processor
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      fi
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+        ;;
+      m68k)
+            # FIXME: we need at least 68020 code to build shared libraries, but
+            # adding the '-m68020' flag to GCC prevents building anything better,
+            # like '-m68040'.
+            _LT_TAGVAR(lt_prog_compiler_pic, $1)='-m68020 -resident32 -malways-restore-a4'
+        ;;
+      esac
+      ;;
+
+    beos* | irix5* | irix6* | nonstopux* | osf3* | osf4* | osf5*)
+      # PIC is the default for these OSes.
+      ;;
+
+    mingw* | cygwin* | pw32* | os2* | cegcc*)
+      # This hack is so that the source file can tell whether it is being
+      # built for inclusion in a dll (and should export symbols for example).
+      # Although the cygwin gcc ignores -fPIC, still need this for old-style
+      # (--disable-auto-import) libraries
+      m4_if([$1], [GCJ], [],
+	[_LT_TAGVAR(lt_prog_compiler_pic, $1)='-DDLL_EXPORT'])
+      case $host_os in
+      os2*)
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='$wl-static'
+	;;
+      esac
+      ;;
+
+    darwin* | rhapsody*)
+      # PIC is the default on this platform
+      # Common symbols not allowed in MH_DYLIB files
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fno-common'
+      ;;
+
+    haiku*)
+      # PIC is the default for Haiku.
+      # The "-static" flag exists, but is broken.
+      _LT_TAGVAR(lt_prog_compiler_static, $1)=
+      ;;
+
+    hpux*)
+      # PIC is the default for 64-bit PA HP-UX, but not for 32-bit
+      # PA HP-UX.  On IA64 HP-UX, PIC is the default but the pic flag
+      # sets the default TLS model and affects inlining.
+      case $host_cpu in
+      hppa*64*)
+	# +Z the default
+	;;
+      *)
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+	;;
+      esac
+      ;;
+
+    interix[[3-9]]*)
+      # Interix 3.x gcc -fpic/-fPIC options generate broken code.
+      # Instead, we relocate shared libraries at runtime.
+      ;;
+
+    msdosdjgpp*)
+      # Just because we use GCC doesn't mean we suddenly get shared libraries
+      # on systems that don't support them.
+      _LT_TAGVAR(lt_prog_compiler_can_build_shared, $1)=no
+      enable_shared=no
+      ;;
+
+    *nto* | *qnx*)
+      # QNX uses GNU C++, but need to define -shared option too, otherwise
+      # it will coredump.
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC -shared'
+      ;;
+
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)=-Kconform_pic
+      fi
+      ;;
+
+    *)
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+      ;;
+    esac
+
+    case $cc_basename in
+    nvcc*) # Cuda Compiler Driver 2.2
+      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Xlinker '
+      if test -n "$_LT_TAGVAR(lt_prog_compiler_pic, $1)"; then
+        _LT_TAGVAR(lt_prog_compiler_pic, $1)="-Xcompiler $_LT_TAGVAR(lt_prog_compiler_pic, $1)"
+      fi
+      ;;
+    esac
+  else
+    # PORTME Check for flag to pass linker flags through the system compiler.
+    case $host_os in
+    aix*)
+      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+      if test ia64 = "$host_cpu"; then
+	# AIX 5 now supports IA64 processor
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      else
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-bnso -bI:/lib/syscalls.exp'
+      fi
+      ;;
+
+    darwin* | rhapsody*)
+      # PIC is the default on this platform
+      # Common symbols not allowed in MH_DYLIB files
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fno-common'
+      case $cc_basename in
+      nagfor*)
+        # NAG Fortran compiler
+        _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,-Wl,,'
+        _LT_TAGVAR(lt_prog_compiler_pic, $1)='-PIC'
+        _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+        ;;
+      esac
+      ;;
+
+    mingw* | cygwin* | pw32* | os2* | cegcc*)
+      # This hack is so that the source file can tell whether it is being
+      # built for inclusion in a dll (and should export symbols for example).
+      m4_if([$1], [GCJ], [],
+	[_LT_TAGVAR(lt_prog_compiler_pic, $1)='-DDLL_EXPORT'])
+      case $host_os in
+      os2*)
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='$wl-static'
+	;;
+      esac
+      ;;
+
+    hpux9* | hpux10* | hpux11*)
+      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+      # PIC is the default for IA64 HP-UX and 64-bit HP-UX, but
+      # not for PA HP-UX.
+      case $host_cpu in
+      hppa*64*|ia64*)
+	# +Z the default
+	;;
+      *)
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='+Z'
+	;;
+      esac
+      # Is there a better lt_prog_compiler_static that works with the bundled CC?
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='$wl-a ${wl}archive'
+      ;;
+
+    irix5* | irix6* | nonstopux*)
+      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+      # PIC (with -KPIC) is the default.
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='-non_shared'
+      ;;
+
+    linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+      case $cc_basename in
+      # old Intel for x86_64, which still supported -KPIC.
+      ecc*)
+	_LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-static'
+        ;;
+      # icc used to be incompatible with GCC.
+      # ICC 10 doesn't accept -KPIC any more.
+      icc* | ifort*)
+	_LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-static'
+        ;;
+      # Lahey Fortran 8.1.
+      lf95*)
+	_LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='--shared'
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='--static'
+	;;
+      nagfor*)
+	# NAG Fortran compiler
+	_LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,-Wl,,'
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='-PIC'
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	;;
+      tcc*)
+	# Fabrice Bellard et al's Tiny C Compiler
+	_LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-static'
+	;;
+      pgcc* | pgf77* | pgf90* | pgf95* | pgfortran*)
+        # Portland Group compilers (*not* the Pentium gcc compiler,
+	# which looks to be a dead project)
+	_LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='-fpic'
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+        ;;
+      ccc*)
+        _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+        # All Alpha code is PIC.
+        _LT_TAGVAR(lt_prog_compiler_static, $1)='-non_shared'
+        ;;
+      xl* | bgxl* | bgf* | mpixl*)
+	# IBM XL C 8.0/Fortran 10.1, 11.1 on PPC and BlueGene
+	_LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='-qpic'
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-qstaticlink'
+	;;
+      *)
+	case `$CC -V 2>&1 | sed 5q` in
+	*Sun\ Ceres\ Fortran* | *Sun*Fortran*\ [[1-7]].* | *Sun*Fortran*\ 8.[[0-3]]*)
+	  # Sun Fortran 8.3 passes all unrecognized flags to the linker
+	  _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	  _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	  _LT_TAGVAR(lt_prog_compiler_wl, $1)=''
+	  ;;
+	*Sun\ F* | *Sun*Fortran*)
+	  _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	  _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	  _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Qoption ld '
+	  ;;
+	*Sun\ C*)
+	  # Sun C 5.9
+	  _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+	  _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	  _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	  ;;
+        *Intel*\ [[CF]]*Compiler*)
+	  _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	  _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+	  _LT_TAGVAR(lt_prog_compiler_static, $1)='-static'
+	  ;;
+	*Portland\ Group*)
+	  _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+	  _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fpic'
+	  _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+	  ;;
+	esac
+	;;
+      esac
+      ;;
+
+    newsos6)
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      ;;
+
+    *nto* | *qnx*)
+      # QNX uses GNU C++, but need to define -shared option too, otherwise
+      # it will coredump.
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC -shared'
+      ;;
+
+    osf3* | osf4* | osf5*)
+      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+      # All OSF/1 code is PIC.
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='-non_shared'
+      ;;
+
+    rdos*)
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='-non_shared'
+      ;;
+
+    solaris*)
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      case $cc_basename in
+      f77* | f90* | f95* | sunf77* | sunf90* | sunf95*)
+	_LT_TAGVAR(lt_prog_compiler_wl, $1)='-Qoption ld ';;
+      *)
+	_LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,';;
+      esac
+      ;;
+
+    sunos4*)
+      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Qoption ld '
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-PIC'
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      ;;
+
+    sysv4 | sysv4.2uw2* | sysv4.3*)
+      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      ;;
+
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	_LT_TAGVAR(lt_prog_compiler_pic, $1)='-Kconform_pic'
+	_LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      fi
+      ;;
+
+    sysv5* | unixware* | sco3.2v5* | sco5v6* | OpenUNIX*)
+      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-KPIC'
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      ;;
+
+    unicos*)
+      _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+      _LT_TAGVAR(lt_prog_compiler_can_build_shared, $1)=no
+      ;;
+
+    uts4*)
+      _LT_TAGVAR(lt_prog_compiler_pic, $1)='-pic'
+      _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
+      ;;
+
+    *)
+      _LT_TAGVAR(lt_prog_compiler_can_build_shared, $1)=no
+      ;;
+    esac
+  fi
+])
+case $host_os in
+  # For platforms that do not support PIC, -DPIC is meaningless:
+  *djgpp*)
+    _LT_TAGVAR(lt_prog_compiler_pic, $1)=
+    ;;
+  *)
+    _LT_TAGVAR(lt_prog_compiler_pic, $1)="$_LT_TAGVAR(lt_prog_compiler_pic, $1)@&t@m4_if([$1],[],[ -DPIC],[m4_if([$1],[CXX],[ -DPIC],[])])"
+    ;;
+esac
+
+AC_CACHE_CHECK([for $compiler option to produce PIC],
+  [_LT_TAGVAR(lt_cv_prog_compiler_pic, $1)],
+  [_LT_TAGVAR(lt_cv_prog_compiler_pic, $1)=$_LT_TAGVAR(lt_prog_compiler_pic, $1)])
+_LT_TAGVAR(lt_prog_compiler_pic, $1)=$_LT_TAGVAR(lt_cv_prog_compiler_pic, $1)
+
+#
+# Check to make sure the PIC flag actually works.
+#
+if test -n "$_LT_TAGVAR(lt_prog_compiler_pic, $1)"; then
+  _LT_COMPILER_OPTION([if $compiler PIC flag $_LT_TAGVAR(lt_prog_compiler_pic, $1) works],
+    [_LT_TAGVAR(lt_cv_prog_compiler_pic_works, $1)],
+    [$_LT_TAGVAR(lt_prog_compiler_pic, $1)@&t@m4_if([$1],[],[ -DPIC],[m4_if([$1],[CXX],[ -DPIC],[])])], [],
+    [case $_LT_TAGVAR(lt_prog_compiler_pic, $1) in
+     "" | " "*) ;;
+     *) _LT_TAGVAR(lt_prog_compiler_pic, $1)=" $_LT_TAGVAR(lt_prog_compiler_pic, $1)" ;;
+     esac],
+    [_LT_TAGVAR(lt_prog_compiler_pic, $1)=
+     _LT_TAGVAR(lt_prog_compiler_can_build_shared, $1)=no])
+fi
+_LT_TAGDECL([pic_flag], [lt_prog_compiler_pic], [1],
+	[Additional compiler flags for building library objects])
+
+_LT_TAGDECL([wl], [lt_prog_compiler_wl], [1],
+	[How to pass a linker flag through the compiler])
+#
+# Check to make sure the static flag actually works.
+#
+wl=$_LT_TAGVAR(lt_prog_compiler_wl, $1) eval lt_tmp_static_flag=\"$_LT_TAGVAR(lt_prog_compiler_static, $1)\"
+_LT_LINKER_OPTION([if $compiler static flag $lt_tmp_static_flag works],
+  _LT_TAGVAR(lt_cv_prog_compiler_static_works, $1),
+  $lt_tmp_static_flag,
+  [],
+  [_LT_TAGVAR(lt_prog_compiler_static, $1)=])
+_LT_TAGDECL([link_static_flag], [lt_prog_compiler_static], [1],
+	[Compiler flag to prevent dynamic linking])
+])# _LT_COMPILER_PIC
+
+
+# _LT_LINKER_SHLIBS([TAGNAME])
+# ----------------------------
+# See if the linker supports building shared libraries.
+m4_defun([_LT_LINKER_SHLIBS],
+[AC_REQUIRE([LT_PATH_LD])dnl
+AC_REQUIRE([LT_PATH_NM])dnl
+m4_require([_LT_PATH_MANIFEST_TOOL])dnl
+m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+m4_require([_LT_DECL_EGREP])dnl
+m4_require([_LT_DECL_SED])dnl
+m4_require([_LT_CMD_GLOBAL_SYMBOLS])dnl
+m4_require([_LT_TAG_COMPILER])dnl
+AC_MSG_CHECKING([whether the $compiler linker ($LD) supports shared libraries])
+m4_if([$1], [CXX], [
+  _LT_TAGVAR(export_symbols_cmds, $1)='$NM $libobjs $convenience | $global_symbol_pipe | $SED '\''s/.* //'\'' | sort | uniq > $export_symbols'
+  _LT_TAGVAR(exclude_expsyms, $1)=['_GLOBAL_OFFSET_TABLE_|_GLOBAL__F[ID]_.*']
+  case $host_os in
+  aix[[4-9]]*)
+    # If we're using GNU nm, then we don't want the "-C" option.
+    # -C means demangle to GNU nm, but means don't demangle to AIX nm.
+    # Without the "-l" option, or with the "-B" option, AIX nm treats
+    # weak defined symbols like other global defined symbols, whereas
+    # GNU nm marks them as "W".
+    # While the 'weak' keyword is ignored in the Export File, we need
+    # it in the Import File for the 'aix-soname' feature, so we have
+    # to replace the "-B" option with "-P" for AIX nm.
+    if $NM -V 2>&1 | $GREP 'GNU' > /dev/null; then
+      _LT_TAGVAR(export_symbols_cmds, $1)='$NM -Bpg $libobjs $convenience | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "W")) && ([substr](\$ 3,1,1) != ".")) { if (\$ 2 == "W") { print \$ 3 " weak" } else { print \$ 3 } } }'\'' | sort -u > $export_symbols'
+    else
+      _LT_TAGVAR(export_symbols_cmds, $1)='`func_echo_all $NM | $SED -e '\''s/B\([[^B]]*\)$/P\1/'\''` -PCpgl $libobjs $convenience | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) && ([substr](\$ 1,1,1) != ".")) { if ((\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) { print \$ 1 " weak" } else { print \$ 1 } } }'\'' | sort -u > $export_symbols'
+    fi
+    ;;
+  pw32*)
+    _LT_TAGVAR(export_symbols_cmds, $1)=$ltdll_cmds
+    ;;
+  cygwin* | mingw* | cegcc*)
+    case $cc_basename in
+    cl*)
+      _LT_TAGVAR(exclude_expsyms, $1)='_NULL_IMPORT_DESCRIPTOR|_IMPORT_DESCRIPTOR_.*'
+      ;;
+    *)
+      _LT_TAGVAR(export_symbols_cmds, $1)='$NM $libobjs $convenience | $global_symbol_pipe | $SED -e '\''/^[[BCDGRS]][[ ]]/s/.*[[ ]]\([[^ ]]*\)/\1 DATA/;s/^.*[[ ]]__nm__\([[^ ]]*\)[[ ]][[^ ]]*/\1 DATA/;/^I[[ ]]/d;/^[[AITW]][[ ]]/s/.* //'\'' | sort | uniq > $export_symbols'
+      _LT_TAGVAR(exclude_expsyms, $1)=['[_]+GLOBAL_OFFSET_TABLE_|[_]+GLOBAL__[FID]_.*|[_]+head_[A-Za-z0-9_]+_dll|[A-Za-z0-9_]+_dll_iname']
+      ;;
+    esac
+    ;;
+  *)
+    _LT_TAGVAR(export_symbols_cmds, $1)='$NM $libobjs $convenience | $global_symbol_pipe | $SED '\''s/.* //'\'' | sort | uniq > $export_symbols'
+    ;;
+  esac
+], [
+  runpath_var=
+  _LT_TAGVAR(allow_undefined_flag, $1)=
+  _LT_TAGVAR(always_export_symbols, $1)=no
+  _LT_TAGVAR(archive_cmds, $1)=
+  _LT_TAGVAR(archive_expsym_cmds, $1)=
+  _LT_TAGVAR(compiler_needs_object, $1)=no
+  _LT_TAGVAR(enable_shared_with_static_runtimes, $1)=no
+  _LT_TAGVAR(export_dynamic_flag_spec, $1)=
+  _LT_TAGVAR(export_symbols_cmds, $1)='$NM $libobjs $convenience | $global_symbol_pipe | $SED '\''s/.* //'\'' | sort | uniq > $export_symbols'
+  _LT_TAGVAR(hardcode_automatic, $1)=no
+  _LT_TAGVAR(hardcode_direct, $1)=no
+  _LT_TAGVAR(hardcode_direct_absolute, $1)=no
+  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)=
+  _LT_TAGVAR(hardcode_libdir_separator, $1)=
+  _LT_TAGVAR(hardcode_minus_L, $1)=no
+  _LT_TAGVAR(hardcode_shlibpath_var, $1)=unsupported
+  _LT_TAGVAR(inherit_rpath, $1)=no
+  _LT_TAGVAR(link_all_deplibs, $1)=unknown
+  _LT_TAGVAR(module_cmds, $1)=
+  _LT_TAGVAR(module_expsym_cmds, $1)=
+  _LT_TAGVAR(old_archive_from_new_cmds, $1)=
+  _LT_TAGVAR(old_archive_from_expsyms_cmds, $1)=
+  _LT_TAGVAR(thread_safe_flag_spec, $1)=
+  _LT_TAGVAR(whole_archive_flag_spec, $1)=
+  # include_expsyms should be a list of space-separated symbols to be *always*
+  # included in the symbol list
+  _LT_TAGVAR(include_expsyms, $1)=
+  # exclude_expsyms can be an extended regexp of symbols to exclude
+  # it will be wrapped by ' (' and ')$', so one must not match beginning or
+  # end of line.  Example: 'a|bc|.*d.*' will exclude the symbols 'a' and 'bc',
+  # as well as any symbol that contains 'd'.
+  _LT_TAGVAR(exclude_expsyms, $1)=['_GLOBAL_OFFSET_TABLE_|_GLOBAL__F[ID]_.*']
+  # Although _GLOBAL_OFFSET_TABLE_ is a valid symbol C name, most a.out
+  # platforms (ab)use it in PIC code, but their linkers get confused if
+  # the symbol is explicitly referenced.  Since portable code cannot
+  # rely on this symbol name, it's probably fine to never include it in
+  # preloaded symbol tables.
+  # Exclude shared library initialization/finalization symbols.
+dnl Note also adjust exclude_expsyms for C++ above.
+  extract_expsyms_cmds=
+
+  case $host_os in
+  cygwin* | mingw* | pw32* | cegcc*)
+    # FIXME: the MSVC++ port hasn't been tested in a loooong time
+    # When not using gcc, we currently assume that we are using
+    # Microsoft Visual C++.
+    if test yes != "$GCC"; then
+      with_gnu_ld=no
+    fi
+    ;;
+  interix*)
+    # we just hope/assume this is gcc and not c89 (= MSVC++)
+    with_gnu_ld=yes
+    ;;
+  openbsd* | bitrig*)
+    with_gnu_ld=no
+    ;;
+  esac
+
+  _LT_TAGVAR(ld_shlibs, $1)=yes
+
+  # On some targets, GNU ld is compatible enough with the native linker
+  # that we're better off using the native interface for both.
+  lt_use_gnu_ld_interface=no
+  if test yes = "$with_gnu_ld"; then
+    case $host_os in
+      aix*)
+	# The AIX port of GNU ld has always aspired to compatibility
+	# with the native linker.  However, as the warning in the GNU ld
+	# block says, versions before 2.19.5* couldn't really create working
+	# shared libraries, regardless of the interface used.
+	case `$LD -v 2>&1` in
+	  *\ \(GNU\ Binutils\)\ 2.19.5*) ;;
+	  *\ \(GNU\ Binutils\)\ 2.[[2-9]]*) ;;
+	  *\ \(GNU\ Binutils\)\ [[3-9]]*) ;;
+	  *)
+	    lt_use_gnu_ld_interface=yes
+	    ;;
+	esac
+	;;
+      *)
+	lt_use_gnu_ld_interface=yes
+	;;
+    esac
+  fi
+
+  if test yes = "$lt_use_gnu_ld_interface"; then
+    # If archive_cmds runs LD, not CC, wlarc should be empty
+    wlarc='$wl'
+
+    # Set some defaults for GNU ld with shared library support. These
+    # are reset later if shared libraries are not supported. Putting them
+    # here allows them to be overridden if necessary.
+    runpath_var=LD_RUN_PATH
+    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+    _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl--export-dynamic'
+    # ancient GNU ld didn't support --whole-archive et. al.
+    if $LD --help 2>&1 | $GREP 'no-whole-archive' > /dev/null; then
+      _LT_TAGVAR(whole_archive_flag_spec, $1)=$wlarc'--whole-archive$convenience '$wlarc'--no-whole-archive'
+    else
+      _LT_TAGVAR(whole_archive_flag_spec, $1)=
+    fi
+    supports_anon_versioning=no
+    case `$LD -v | $SED -e 's/([^)]\+)\s\+//' 2>&1` in
+      *GNU\ gold*) supports_anon_versioning=yes ;;
+      *\ [[01]].* | *\ 2.[[0-9]].* | *\ 2.10.*) ;; # catch versions < 2.11
+      *\ 2.11.93.0.2\ *) supports_anon_versioning=yes ;; # RH7.3 ...
+      *\ 2.11.92.0.12\ *) supports_anon_versioning=yes ;; # Mandrake 8.2 ...
+      *\ 2.11.*) ;; # other 2.11 versions
+      *) supports_anon_versioning=yes ;;
+    esac
+
+    # See if GNU ld supports shared libraries.
+    case $host_os in
+    aix[[3-9]]*)
+      # On AIX/PPC, the GNU linker is very broken
+      if test ia64 != "$host_cpu"; then
+	_LT_TAGVAR(ld_shlibs, $1)=no
+	cat <<_LT_EOF 1>&2
+
+*** Warning: the GNU linker, at least up to release 2.19, is reported
+*** to be unable to reliably create shared libraries on AIX.
+*** Therefore, libtool is disabling shared libraries support.  If you
+*** really care for shared libraries, you may want to install binutils
+*** 2.20 or above, or modify your PATH so that a non-GNU linker is found.
+*** You will then need to restart the configuration process.
+
+_LT_EOF
+      fi
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            _LT_TAGVAR(archive_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+            _LT_TAGVAR(archive_expsym_cmds, $1)=''
+        ;;
+      m68k)
+            _LT_TAGVAR(archive_cmds, $1)='$RM $output_objdir/a2ixlibrary.data~$ECHO "#define NAME $libname" > $output_objdir/a2ixlibrary.data~$ECHO "#define LIBRARY_ID 1" >> $output_objdir/a2ixlibrary.data~$ECHO "#define VERSION $major" >> $output_objdir/a2ixlibrary.data~$ECHO "#define REVISION $revision" >> $output_objdir/a2ixlibrary.data~$AR $AR_FLAGS $lib $libobjs~$RANLIB $lib~(cd $output_objdir && a2ixlibrary -32)'
+            _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+            _LT_TAGVAR(hardcode_minus_L, $1)=yes
+        ;;
+      esac
+      ;;
+
+    beos*)
+      if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	_LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+	# Joseph Beckenbach <jrb3@best.com> says some releases of gcc
+	# support --undefined.  This deserves some investigation.  FIXME
+	_LT_TAGVAR(archive_cmds, $1)='$CC -nostart $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+      else
+	_LT_TAGVAR(ld_shlibs, $1)=no
+      fi
+      ;;
+
+    cygwin* | mingw* | pw32* | cegcc*)
+      # _LT_TAGVAR(hardcode_libdir_flag_spec, $1) is actually meaningless,
+      # as there is no search path for DLLs.
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+      _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl--export-all-symbols'
+      _LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+      _LT_TAGVAR(always_export_symbols, $1)=no
+      _LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+      _LT_TAGVAR(export_symbols_cmds, $1)='$NM $libobjs $convenience | $global_symbol_pipe | $SED -e '\''/^[[BCDGRS]][[ ]]/s/.*[[ ]]\([[^ ]]*\)/\1 DATA/;s/^.*[[ ]]__nm__\([[^ ]]*\)[[ ]][[^ ]]*/\1 DATA/;/^I[[ ]]/d;/^[[AITW]][[ ]]/s/.* //'\'' | sort | uniq > $export_symbols'
+      _LT_TAGVAR(exclude_expsyms, $1)=['[_]+GLOBAL_OFFSET_TABLE_|[_]+GLOBAL__[FID]_.*|[_]+head_[A-Za-z0-9_]+_dll|[A-Za-z0-9_]+_dll_iname']
+
+      if $LD --help 2>&1 | $GREP 'auto-import' > /dev/null; then
+        _LT_TAGVAR(archive_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
+	# If the export-symbols file already is a .def file, use it as
+	# is; otherwise, prepend EXPORTS...
+	_LT_TAGVAR(archive_expsym_cmds, $1)='if _LT_DLL_DEF_P([$export_symbols]); then
+          cp $export_symbols $output_objdir/$soname.def;
+        else
+          echo EXPORTS > $output_objdir/$soname.def;
+          cat $export_symbols >> $output_objdir/$soname.def;
+        fi~
+        $CC -shared $output_objdir/$soname.def $libobjs $deplibs $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
+      else
+	_LT_TAGVAR(ld_shlibs, $1)=no
+      fi
+      ;;
+
+    haiku*)
+      _LT_TAGVAR(archive_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+      _LT_TAGVAR(link_all_deplibs, $1)=yes
+      ;;
+
+    os2*)
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+      _LT_TAGVAR(hardcode_minus_L, $1)=yes
+      _LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+      shrext_cmds=.dll
+      _LT_TAGVAR(archive_cmds, $1)='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	emxexp $libobjs | $SED /"_DLL_InitTerm"/d >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      _LT_TAGVAR(archive_expsym_cmds, $1)='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	prefix_cmds="$SED"~
+	if test EXPORTS = "`$SED 1q $export_symbols`"; then
+	  prefix_cmds="$prefix_cmds -e 1d";
+	fi~
+	prefix_cmds="$prefix_cmds -e \"s/^\(.*\)$/_\1/g\""~
+	cat $export_symbols | $prefix_cmds >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      _LT_TAGVAR(old_archive_From_new_cmds, $1)='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
+      _LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+      ;;
+
+    interix[[3-9]]*)
+      _LT_TAGVAR(hardcode_direct, $1)=no
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath,$libdir'
+      _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-E'
+      # Hack: On Interix 3.x, we cannot compile PIC because of a broken gcc.
+      # Instead, shared libraries are loaded at an image base (0x10000000 by
+      # default) and relocated if they conflict, which is a slow very memory
+      # consuming and fragmenting process.  To avoid this, we pick a random,
+      # 256 KiB-aligned image base between 0x50000000 and 0x6FFC0000 at link
+      # time.  Moving up from 0x10000000 also allows more sbrk(2) space.
+      _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-h,$soname $wl--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
+      _LT_TAGVAR(archive_expsym_cmds, $1)='sed "s|^|_|" $export_symbols >$output_objdir/$soname.expsym~$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-h,$soname $wl--retain-symbols-file,$output_objdir/$soname.expsym $wl--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
+      ;;
+
+    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu)
+      tmp_diet=no
+      if test linux-dietlibc = "$host_os"; then
+	case $cc_basename in
+	  diet\ *) tmp_diet=yes;;	# linux-dietlibc with static linking (!diet-dyn)
+	esac
+      fi
+      if $LD --help 2>&1 | $EGREP ': supported targets:.* elf' > /dev/null \
+	 && test no = "$tmp_diet"
+      then
+	tmp_addflag=' $pic_flag'
+	tmp_sharedflag='-shared'
+	case $cc_basename,$host_cpu in
+        pgcc*)				# Portland Group C compiler
+	  _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  tmp_addflag=' $pic_flag'
+	  ;;
+	pgf77* | pgf90* | pgf95* | pgfortran*)
+					# Portland Group f77 and f90 compilers
+	  _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  tmp_addflag=' $pic_flag -Mnomain' ;;
+	ecc*,ia64* | icc*,ia64*)	# Intel C compiler on ia64
+	  tmp_addflag=' -i_dynamic' ;;
+	efc*,ia64* | ifort*,ia64*)	# Intel Fortran compiler on ia64
+	  tmp_addflag=' -i_dynamic -nofor_main' ;;
+	ifc* | ifort*)			# Intel Fortran compiler
+	  tmp_addflag=' -nofor_main' ;;
+	lf95*)				# Lahey Fortran 8.1
+	  _LT_TAGVAR(whole_archive_flag_spec, $1)=
+	  tmp_sharedflag='--shared' ;;
+        nagfor*)                        # NAGFOR 5.3
+          tmp_sharedflag='-Wl,-shared' ;;
+	xl[[cC]]* | bgxl[[cC]]* | mpixl[[cC]]*) # IBM XL C 8.0 on PPC (deal with xlf below)
+	  tmp_sharedflag='-qmkshrobj'
+	  tmp_addflag= ;;
+	nvcc*)	# Cuda Compiler Driver 2.2
+	  _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  _LT_TAGVAR(compiler_needs_object, $1)=yes
+	  ;;
+	esac
+	case `$CC -V 2>&1 | sed 5q` in
+	*Sun\ C*)			# Sun C 5.9
+	  _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl--whole-archive`new_convenience=; for conv in $convenience\"\"; do test -z \"$conv\" || new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  _LT_TAGVAR(compiler_needs_object, $1)=yes
+	  tmp_sharedflag='-G' ;;
+	*Sun\ F*)			# Sun Fortran 8.3
+	  tmp_sharedflag='-G' ;;
+	esac
+	_LT_TAGVAR(archive_cmds, $1)='$CC '"$tmp_sharedflag""$tmp_addflag"' $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+
+        if test yes = "$supports_anon_versioning"; then
+          _LT_TAGVAR(archive_expsym_cmds, $1)='echo "{ global:" > $output_objdir/$libname.ver~
+            cat $export_symbols | sed -e "s/\(.*\)/\1;/" >> $output_objdir/$libname.ver~
+            echo "local: *; };" >> $output_objdir/$libname.ver~
+            $CC '"$tmp_sharedflag""$tmp_addflag"' $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-version-script $wl$output_objdir/$libname.ver -o $lib'
+        fi
+
+	case $cc_basename in
+	tcc*)
+	  _LT_TAGVAR(export_dynamic_flag_spec, $1)='-rdynamic'
+	  ;;
+	xlf* | bgf* | bgxlf* | mpixlf*)
+	  # IBM XL Fortran 10.1 on PPC cannot create shared libs itself
+	  _LT_TAGVAR(whole_archive_flag_spec, $1)='--whole-archive$convenience --no-whole-archive'
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+	  _LT_TAGVAR(archive_cmds, $1)='$LD -shared $libobjs $deplibs $linker_flags -soname $soname -o $lib'
+	  if test yes = "$supports_anon_versioning"; then
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='echo "{ global:" > $output_objdir/$libname.ver~
+              cat $export_symbols | sed -e "s/\(.*\)/\1;/" >> $output_objdir/$libname.ver~
+              echo "local: *; };" >> $output_objdir/$libname.ver~
+              $LD -shared $libobjs $deplibs $linker_flags -soname $soname -version-script $output_objdir/$libname.ver -o $lib'
+	  fi
+	  ;;
+	esac
+      else
+        _LT_TAGVAR(ld_shlibs, $1)=no
+      fi
+      ;;
+
+    netbsd*)
+      if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+	_LT_TAGVAR(archive_cmds, $1)='$LD -Bshareable $libobjs $deplibs $linker_flags -o $lib'
+	wlarc=
+      else
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+      fi
+      ;;
+
+    solaris*)
+      if $LD -v 2>&1 | $GREP 'BFD 2\.8' > /dev/null; then
+	_LT_TAGVAR(ld_shlibs, $1)=no
+	cat <<_LT_EOF 1>&2
+
+*** Warning: The releases 2.8.* of the GNU linker cannot reliably
+*** create shared libraries on Solaris systems.  Therefore, libtool
+*** is disabling shared libraries support.  We urge you to upgrade GNU
+*** binutils to release 2.9.1 or newer.  Another option is to modify
+*** your PATH or compiler configuration so that the native linker is
+*** used, and then restart.
+
+_LT_EOF
+      elif $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+      else
+	_LT_TAGVAR(ld_shlibs, $1)=no
+      fi
+      ;;
+
+    sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX*)
+      case `$LD -v 2>&1` in
+        *\ [[01]].* | *\ 2.[[0-9]].* | *\ 2.1[[0-5]].*)
+	_LT_TAGVAR(ld_shlibs, $1)=no
+	cat <<_LT_EOF 1>&2
+
+*** Warning: Releases of the GNU linker prior to 2.16.91.0.3 cannot
+*** reliably create shared libraries on SCO systems.  Therefore, libtool
+*** is disabling shared libraries support.  We urge you to upgrade GNU
+*** binutils to release 2.16.91.0.3 or newer.  Another option is to modify
+*** your PATH or compiler configuration so that the native linker is
+*** used, and then restart.
+
+_LT_EOF
+	;;
+	*)
+	  # For security reasons, it is highly recommended that you always
+	  # use absolute paths for naming shared libraries, and exclude the
+	  # DT_RUNPATH tag from executables and libraries.  But doing so
+	  # requires that you compile everything twice, which is a pain.
+	  if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+	    _LT_TAGVAR(archive_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+	  else
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	  fi
+	;;
+      esac
+      ;;
+
+    sunos4*)
+      _LT_TAGVAR(archive_cmds, $1)='$LD -assert pure-text -Bshareable -o $lib $libobjs $deplibs $linker_flags'
+      wlarc=
+      _LT_TAGVAR(hardcode_direct, $1)=yes
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    *)
+      if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+      else
+	_LT_TAGVAR(ld_shlibs, $1)=no
+      fi
+      ;;
+    esac
+
+    if test no = "$_LT_TAGVAR(ld_shlibs, $1)"; then
+      runpath_var=
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)=
+      _LT_TAGVAR(export_dynamic_flag_spec, $1)=
+      _LT_TAGVAR(whole_archive_flag_spec, $1)=
+    fi
+  else
+    # PORTME fill in a description of your system's linker (not GNU ld)
+    case $host_os in
+    aix3*)
+      _LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+      _LT_TAGVAR(always_export_symbols, $1)=yes
+      _LT_TAGVAR(archive_expsym_cmds, $1)='$LD -o $output_objdir/$soname $libobjs $deplibs $linker_flags -bE:$export_symbols -T512 -H512 -bM:SRE~$AR $AR_FLAGS $lib $output_objdir/$soname'
+      # Note: this linker hardcodes the directories in LIBPATH if there
+      # are no directories specified by -L.
+      _LT_TAGVAR(hardcode_minus_L, $1)=yes
+      if test yes = "$GCC" && test -z "$lt_prog_compiler_static"; then
+	# Neither direct hardcoding nor static linking is supported with a
+	# broken collect2.
+	_LT_TAGVAR(hardcode_direct, $1)=unsupported
+      fi
+      ;;
+
+    aix[[4-9]]*)
+      if test ia64 = "$host_cpu"; then
+	# On IA64, the linker does run time linking by default, so we don't
+	# have to do anything special.
+	aix_use_runtimelinking=no
+	exp_sym_flag='-Bexport'
+	no_entry_flag=
+      else
+	# If we're using GNU nm, then we don't want the "-C" option.
+	# -C means demangle to GNU nm, but means don't demangle to AIX nm.
+	# Without the "-l" option, or with the "-B" option, AIX nm treats
+	# weak defined symbols like other global defined symbols, whereas
+	# GNU nm marks them as "W".
+	# While the 'weak' keyword is ignored in the Export File, we need
+	# it in the Import File for the 'aix-soname' feature, so we have
+	# to replace the "-B" option with "-P" for AIX nm.
+	if $NM -V 2>&1 | $GREP 'GNU' > /dev/null; then
+	  _LT_TAGVAR(export_symbols_cmds, $1)='$NM -Bpg $libobjs $convenience | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "W")) && ([substr](\$ 3,1,1) != ".")) { if (\$ 2 == "W") { print \$ 3 " weak" } else { print \$ 3 } } }'\'' | sort -u > $export_symbols'
+	else
+	  _LT_TAGVAR(export_symbols_cmds, $1)='`func_echo_all $NM | $SED -e '\''s/B\([[^B]]*\)$/P\1/'\''` -PCpgl $libobjs $convenience | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) && ([substr](\$ 1,1,1) != ".")) { if ((\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) { print \$ 1 " weak" } else { print \$ 1 } } }'\'' | sort -u > $export_symbols'
+	fi
+	aix_use_runtimelinking=no
+
+	# Test if we are trying to use run time linking or normal
+	# AIX style linking. If -brtl is somewhere in LDFLAGS, we
+	# have runtime linking enabled, and use it for executables.
+	# For shared libraries, we enable/disable runtime linking
+	# depending on the kind of the shared library created -
+	# when "with_aix_soname,aix_use_runtimelinking" is:
+	# "aix,no"   lib.a(lib.so.V) shared, rtl:no,  for executables
+	# "aix,yes"  lib.so          shared, rtl:yes, for executables
+	#            lib.a           static archive
+	# "both,no"  lib.so.V(shr.o) shared, rtl:yes
+	#            lib.a(lib.so.V) shared, rtl:no,  for executables
+	# "both,yes" lib.so.V(shr.o) shared, rtl:yes, for executables
+	#            lib.a(lib.so.V) shared, rtl:no
+	# "svr4,*"   lib.so.V(shr.o) shared, rtl:yes, for executables
+	#            lib.a           static archive
+	case $host_os in aix4.[[23]]|aix4.[[23]].*|aix[[5-9]]*)
+	  for ld_flag in $LDFLAGS; do
+	  if (test x-brtl = "x$ld_flag" || test x-Wl,-brtl = "x$ld_flag"); then
+	    aix_use_runtimelinking=yes
+	    break
+	  fi
+	  done
+	  if test svr4,no = "$with_aix_soname,$aix_use_runtimelinking"; then
+	    # With aix-soname=svr4, we create the lib.so.V shared archives only,
+	    # so we don't have lib.a shared libs to link our executables.
+	    # We have to force runtime linking in this case.
+	    aix_use_runtimelinking=yes
+	    LDFLAGS="$LDFLAGS -Wl,-brtl"
+	  fi
+	  ;;
+	esac
+
+	exp_sym_flag='-bexport'
+	no_entry_flag='-bnoentry'
+      fi
+
+      # When large executables or shared objects are built, AIX ld can
+      # have problems creating the table of contents.  If linking a library
+      # or program results in "error TOC overflow" add -mminimal-toc to
+      # CXXFLAGS/CFLAGS for g++/gcc.  In the cases where that is not
+      # enough to fix the problem, add -Wl,-bbigtoc to LDFLAGS.
+
+      _LT_TAGVAR(archive_cmds, $1)=''
+      _LT_TAGVAR(hardcode_direct, $1)=yes
+      _LT_TAGVAR(hardcode_direct_absolute, $1)=yes
+      _LT_TAGVAR(hardcode_libdir_separator, $1)=':'
+      _LT_TAGVAR(link_all_deplibs, $1)=yes
+      _LT_TAGVAR(file_list_spec, $1)='$wl-f,'
+      case $with_aix_soname,$aix_use_runtimelinking in
+      aix,*) ;; # traditional, no import file
+      svr4,* | *,yes) # use import file
+	# The Import File defines what to hardcode.
+	_LT_TAGVAR(hardcode_direct, $1)=no
+	_LT_TAGVAR(hardcode_direct_absolute, $1)=no
+	;;
+      esac
+
+      if test yes = "$GCC"; then
+	case $host_os in aix4.[[012]]|aix4.[[012]].*)
+	# We only want to do this on AIX 4.2 and lower, the check
+	# below for broken collect2 doesn't work under 4.3+
+	  collect2name=`$CC -print-prog-name=collect2`
+	  if test -f "$collect2name" &&
+	   strings "$collect2name" | $GREP resolve_lib_name >/dev/null
+	  then
+	  # We have reworked collect2
+	  :
+	  else
+	  # We have old collect2
+	  _LT_TAGVAR(hardcode_direct, $1)=unsupported
+	  # It fails to find uninstalled libraries when the uninstalled
+	  # path is not listed in the libpath.  Setting hardcode_minus_L
+	  # to unsupported forces relinking
+	  _LT_TAGVAR(hardcode_minus_L, $1)=yes
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+	  _LT_TAGVAR(hardcode_libdir_separator, $1)=
+	  fi
+	  ;;
+	esac
+	shared_flag='-shared'
+	if test yes = "$aix_use_runtimelinking"; then
+	  shared_flag="$shared_flag "'$wl-G'
+	fi
+	# Need to ensure runtime linking is disabled for the traditional
+	# shared library, or the linker may eventually find shared libraries
+	# /with/ Import File - we do not want to mix them.
+	shared_flag_aix='-shared'
+	shared_flag_svr4='-shared $wl-G'
+      else
+	# not using gcc
+	if test ia64 = "$host_cpu"; then
+	# VisualAge C++, Version 5.5 for AIX 5L for IA-64, Beta 3 Release
+	# chokes on -Wl,-G. The following line is correct:
+	  shared_flag='-G'
+	else
+	  if test yes = "$aix_use_runtimelinking"; then
+	    shared_flag='$wl-G'
+	  else
+	    shared_flag='$wl-bM:SRE'
+	  fi
+	  shared_flag_aix='$wl-bM:SRE'
+	  shared_flag_svr4='$wl-G'
+	fi
+      fi
+
+      _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-bexpall'
+      # It seems that -bexpall does not export symbols beginning with
+      # underscore (_), so it is better to generate a list of symbols to export.
+      _LT_TAGVAR(always_export_symbols, $1)=yes
+      if test aix,yes = "$with_aix_soname,$aix_use_runtimelinking"; then
+	# Warning - without using the other runtime loading flags (-brtl),
+	# -berok will link without error, but may produce a broken library.
+	_LT_TAGVAR(allow_undefined_flag, $1)='-berok'
+        # Determine the default libpath from the value encoded in an
+        # empty executable.
+        _LT_SYS_MODULE_PATH_AIX([$1])
+        _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-blibpath:$libdir:'"$aix_libpath"
+        _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -o $output_objdir/$soname $libobjs $deplibs $wl'$no_entry_flag' $compiler_flags `if test -n "$allow_undefined_flag"; then func_echo_all "$wl$allow_undefined_flag"; else :; fi` $wl'$exp_sym_flag:\$export_symbols' '$shared_flag
+      else
+	if test ia64 = "$host_cpu"; then
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-R $libdir:/usr/lib:/lib'
+	  _LT_TAGVAR(allow_undefined_flag, $1)="-z nodefs"
+	  _LT_TAGVAR(archive_expsym_cmds, $1)="\$CC $shared_flag"' -o $output_objdir/$soname $libobjs $deplibs '"\$wl$no_entry_flag"' $compiler_flags $wl$allow_undefined_flag '"\$wl$exp_sym_flag:\$export_symbols"
+	else
+	 # Determine the default libpath from the value encoded in an
+	 # empty executable.
+	 _LT_SYS_MODULE_PATH_AIX([$1])
+	 _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-blibpath:$libdir:'"$aix_libpath"
+	  # Warning - without using the other run time loading flags,
+	  # -berok will link without error, but may produce a broken library.
+	  _LT_TAGVAR(no_undefined_flag, $1)=' $wl-bernotok'
+	  _LT_TAGVAR(allow_undefined_flag, $1)=' $wl-berok'
+	  if test yes = "$with_gnu_ld"; then
+	    # We only use this code for GNU lds that support --whole-archive.
+	    _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl--whole-archive$convenience $wl--no-whole-archive'
+	  else
+	    # Exported symbols can be pulled into shared objects from archives
+	    _LT_TAGVAR(whole_archive_flag_spec, $1)='$convenience'
+	  fi
+	  _LT_TAGVAR(archive_cmds_need_lc, $1)=yes
+	  _LT_TAGVAR(archive_expsym_cmds, $1)='$RM -r $output_objdir/$realname.d~$MKDIR $output_objdir/$realname.d'
+	  # -brtl affects multiple linker settings, -berok does not and is overridden later
+	  compiler_flags_filtered='`func_echo_all "$compiler_flags " | $SED -e "s%-brtl\\([[, ]]\\)%-berok\\1%g"`'
+	  if test svr4 != "$with_aix_soname"; then
+	    # This is similar to how AIX traditionally builds its shared libraries.
+	    _LT_TAGVAR(archive_expsym_cmds, $1)="$_LT_TAGVAR(archive_expsym_cmds, $1)"'~$CC '$shared_flag_aix' -o $output_objdir/$realname.d/$soname $libobjs $deplibs $wl-bnoentry '$compiler_flags_filtered'$wl-bE:$export_symbols$allow_undefined_flag~$AR $AR_FLAGS $output_objdir/$libname$release.a $output_objdir/$realname.d/$soname'
+	  fi
+	  if test aix != "$with_aix_soname"; then
+	    _LT_TAGVAR(archive_expsym_cmds, $1)="$_LT_TAGVAR(archive_expsym_cmds, $1)"'~$CC '$shared_flag_svr4' -o $output_objdir/$realname.d/$shared_archive_member_spec.o $libobjs $deplibs $wl-bnoentry '$compiler_flags_filtered'$wl-bE:$export_symbols$allow_undefined_flag~$STRIP -e $output_objdir/$realname.d/$shared_archive_member_spec.o~( func_echo_all "#! $soname($shared_archive_member_spec.o)"; if test shr_64 = "$shared_archive_member_spec"; then func_echo_all "# 64"; else func_echo_all "# 32"; fi; cat $export_symbols ) > $output_objdir/$realname.d/$shared_archive_member_spec.imp~$AR $AR_FLAGS $output_objdir/$soname $output_objdir/$realname.d/$shared_archive_member_spec.o $output_objdir/$realname.d/$shared_archive_member_spec.imp'
+	  else
+	    # used by -dlpreopen to get the symbols
+	    _LT_TAGVAR(archive_expsym_cmds, $1)="$_LT_TAGVAR(archive_expsym_cmds, $1)"'~$MV  $output_objdir/$realname.d/$soname $output_objdir'
+	  fi
+	  _LT_TAGVAR(archive_expsym_cmds, $1)="$_LT_TAGVAR(archive_expsym_cmds, $1)"'~$RM -r $output_objdir/$realname.d'
+	fi
+      fi
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            _LT_TAGVAR(archive_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+            _LT_TAGVAR(archive_expsym_cmds, $1)=''
+        ;;
+      m68k)
+            _LT_TAGVAR(archive_cmds, $1)='$RM $output_objdir/a2ixlibrary.data~$ECHO "#define NAME $libname" > $output_objdir/a2ixlibrary.data~$ECHO "#define LIBRARY_ID 1" >> $output_objdir/a2ixlibrary.data~$ECHO "#define VERSION $major" >> $output_objdir/a2ixlibrary.data~$ECHO "#define REVISION $revision" >> $output_objdir/a2ixlibrary.data~$AR $AR_FLAGS $lib $libobjs~$RANLIB $lib~(cd $output_objdir && a2ixlibrary -32)'
+            _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+            _LT_TAGVAR(hardcode_minus_L, $1)=yes
+        ;;
+      esac
+      ;;
+
+    bsdi[[45]]*)
+      _LT_TAGVAR(export_dynamic_flag_spec, $1)=-rdynamic
+      ;;
+
+    cygwin* | mingw* | pw32* | cegcc*)
+      # When not using gcc, we currently assume that we are using
+      # Microsoft Visual C++.
+      # hardcode_libdir_flag_spec is actually meaningless, as there is
+      # no search path for DLLs.
+      case $cc_basename in
+      cl*)
+	# Native MSVC
+	_LT_TAGVAR(hardcode_libdir_flag_spec, $1)=' '
+	_LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+	_LT_TAGVAR(always_export_symbols, $1)=yes
+	_LT_TAGVAR(file_list_spec, $1)='@'
+	# Tell ltmain to make .lib files, not .a files.
+	libext=lib
+	# Tell ltmain to make .dll files, not .so files.
+	shrext_cmds=.dll
+	# FIXME: Setting linknames here is a bad hack.
+	_LT_TAGVAR(archive_cmds, $1)='$CC -o $output_objdir/$soname $libobjs $compiler_flags $deplibs -Wl,-DLL,-IMPLIB:"$tool_output_objdir$libname.dll.lib"~linknames='
+	_LT_TAGVAR(archive_expsym_cmds, $1)='if _LT_DLL_DEF_P([$export_symbols]); then
+            cp "$export_symbols" "$output_objdir/$soname.def";
+            echo "$tool_output_objdir$soname.def" > "$output_objdir/$soname.exp";
+          else
+            $SED -e '\''s/^/-link -EXPORT:/'\'' < $export_symbols > $output_objdir/$soname.exp;
+          fi~
+          $CC -o $tool_output_objdir$soname $libobjs $compiler_flags $deplibs "@$tool_output_objdir$soname.exp" -Wl,-DLL,-IMPLIB:"$tool_output_objdir$libname.dll.lib"~
+          linknames='
+	# The linker will not automatically build a static lib if we build a DLL.
+	# _LT_TAGVAR(old_archive_from_new_cmds, $1)='true'
+	_LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+	_LT_TAGVAR(exclude_expsyms, $1)='_NULL_IMPORT_DESCRIPTOR|_IMPORT_DESCRIPTOR_.*'
+	_LT_TAGVAR(export_symbols_cmds, $1)='$NM $libobjs $convenience | $global_symbol_pipe | $SED -e '\''/^[[BCDGRS]][[ ]]/s/.*[[ ]]\([[^ ]]*\)/\1,DATA/'\'' | $SED -e '\''/^[[AITW]][[ ]]/s/.*[[ ]]//'\'' | sort | uniq > $export_symbols'
+	# Don't use ranlib
+	_LT_TAGVAR(old_postinstall_cmds, $1)='chmod 644 $oldlib'
+	_LT_TAGVAR(postlink_cmds, $1)='lt_outputfile="@OUTPUT@"~
+          lt_tool_outputfile="@TOOL_OUTPUT@"~
+          case $lt_outputfile in
+            *.exe|*.EXE) ;;
+            *)
+              lt_outputfile=$lt_outputfile.exe
+              lt_tool_outputfile=$lt_tool_outputfile.exe
+              ;;
+          esac~
+          if test : != "$MANIFEST_TOOL" && test -f "$lt_outputfile.manifest"; then
+            $MANIFEST_TOOL -manifest "$lt_tool_outputfile.manifest" -outputresource:"$lt_tool_outputfile" || exit 1;
+            $RM "$lt_outputfile.manifest";
+          fi'
+	;;
+      *)
+	# Assume MSVC wrapper
+	_LT_TAGVAR(hardcode_libdir_flag_spec, $1)=' '
+	_LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+	# Tell ltmain to make .lib files, not .a files.
+	libext=lib
+	# Tell ltmain to make .dll files, not .so files.
+	shrext_cmds=.dll
+	# FIXME: Setting linknames here is a bad hack.
+	_LT_TAGVAR(archive_cmds, $1)='$CC -o $lib $libobjs $compiler_flags `func_echo_all "$deplibs" | $SED '\''s/ -lc$//'\''` -link -dll~linknames='
+	# The linker will automatically build a .lib file if we build a DLL.
+	_LT_TAGVAR(old_archive_from_new_cmds, $1)='true'
+	# FIXME: Should let the user specify the lib program.
+	_LT_TAGVAR(old_archive_cmds, $1)='lib -OUT:$oldlib$oldobjs$old_deplibs'
+	_LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+	;;
+      esac
+      ;;
+
+    darwin* | rhapsody*)
+      _LT_DARWIN_LINKER_FEATURES($1)
+      ;;
+
+    dgux*)
+      _LT_TAGVAR(archive_cmds, $1)='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    # FreeBSD 2.2.[012] allows us to include c++rt0.o to get C++ constructor
+    # support.  Future versions do this automatically, but an explicit c++rt0.o
+    # does not break anything, and helps significantly (at the cost of a little
+    # extra space).
+    freebsd2.2*)
+      _LT_TAGVAR(archive_cmds, $1)='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags /usr/lib/c++rt0.o'
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-R$libdir'
+      _LT_TAGVAR(hardcode_direct, $1)=yes
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    # Unfortunately, older versions of FreeBSD 2 do not have this feature.
+    freebsd2.*)
+      _LT_TAGVAR(archive_cmds, $1)='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags'
+      _LT_TAGVAR(hardcode_direct, $1)=yes
+      _LT_TAGVAR(hardcode_minus_L, $1)=yes
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    # FreeBSD 3 and greater uses gcc -shared to do shared libraries.
+    freebsd* | dragonfly*)
+      _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-R$libdir'
+      _LT_TAGVAR(hardcode_direct, $1)=yes
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    hpux9*)
+      if test yes = "$GCC"; then
+	_LT_TAGVAR(archive_cmds, $1)='$RM $output_objdir/$soname~$CC -shared $pic_flag $wl+b $wl$install_libdir -o $output_objdir/$soname $libobjs $deplibs $compiler_flags~test "x$output_objdir/$soname" = "x$lib" || mv $output_objdir/$soname $lib'
+      else
+	_LT_TAGVAR(archive_cmds, $1)='$RM $output_objdir/$soname~$LD -b +b $install_libdir -o $output_objdir/$soname $libobjs $deplibs $linker_flags~test "x$output_objdir/$soname" = "x$lib" || mv $output_objdir/$soname $lib'
+      fi
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl+b $wl$libdir'
+      _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+      _LT_TAGVAR(hardcode_direct, $1)=yes
+
+      # hardcode_minus_L: Not really in the search PATH,
+      # but as the default location of the library.
+      _LT_TAGVAR(hardcode_minus_L, $1)=yes
+      _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-E'
+      ;;
+
+    hpux10*)
+      if test yes,no = "$GCC,$with_gnu_ld"; then
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	_LT_TAGVAR(archive_cmds, $1)='$LD -b +h $soname +b $install_libdir -o $lib $libobjs $deplibs $linker_flags'
+      fi
+      if test no = "$with_gnu_ld"; then
+	_LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl+b $wl$libdir'
+	_LT_TAGVAR(hardcode_libdir_separator, $1)=:
+	_LT_TAGVAR(hardcode_direct, $1)=yes
+	_LT_TAGVAR(hardcode_direct_absolute, $1)=yes
+	_LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-E'
+	# hardcode_minus_L: Not really in the search PATH,
+	# but as the default location of the library.
+	_LT_TAGVAR(hardcode_minus_L, $1)=yes
+      fi
+      ;;
+
+    hpux11*)
+      if test yes,no = "$GCC,$with_gnu_ld"; then
+	case $host_cpu in
+	hppa*64*)
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -shared $wl+h $wl$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	ia64*)
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $wl+h $wl$soname $wl+nodefaultrpath -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	*)
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	esac
+      else
+	case $host_cpu in
+	hppa*64*)
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -b $wl+h $wl$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	ia64*)
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -b $wl+h $wl$soname $wl+nodefaultrpath -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	*)
+	m4_if($1, [], [
+	  # Older versions of the 11.00 compiler do not understand -b yet
+	  # (HP92453-01 A.11.01.20 doesn't, HP92453-01 B.11.X.35175-35176.GP does)
+	  _LT_LINKER_OPTION([if $CC understands -b],
+	    _LT_TAGVAR(lt_cv_prog_compiler__b, $1), [-b],
+	    [_LT_TAGVAR(archive_cmds, $1)='$CC -b $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'],
+	    [_LT_TAGVAR(archive_cmds, $1)='$LD -b +h $soname +b $install_libdir -o $lib $libobjs $deplibs $linker_flags'])],
+	  [_LT_TAGVAR(archive_cmds, $1)='$CC -b $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'])
+	  ;;
+	esac
+      fi
+      if test no = "$with_gnu_ld"; then
+	_LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl+b $wl$libdir'
+	_LT_TAGVAR(hardcode_libdir_separator, $1)=:
+
+	case $host_cpu in
+	hppa*64*|ia64*)
+	  _LT_TAGVAR(hardcode_direct, $1)=no
+	  _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+	  ;;
+	*)
+	  _LT_TAGVAR(hardcode_direct, $1)=yes
+	  _LT_TAGVAR(hardcode_direct_absolute, $1)=yes
+	  _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-E'
+
+	  # hardcode_minus_L: Not really in the search PATH,
+	  # but as the default location of the library.
+	  _LT_TAGVAR(hardcode_minus_L, $1)=yes
+	  ;;
+	esac
+      fi
+      ;;
+
+    irix5* | irix6* | nonstopux*)
+      if test yes = "$GCC"; then
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+	# Try to use the -exported_symbol ld option, if it does not
+	# work, assume that -exports_file does not work either and
+	# implicitly export all symbols.
+	# This should be the same for all languages, so no per-tag cache variable.
+	AC_CACHE_CHECK([whether the $host_os linker accepts -exported_symbol],
+	  [lt_cv_irix_exported_symbol],
+	  [save_LDFLAGS=$LDFLAGS
+	   LDFLAGS="$LDFLAGS -shared $wl-exported_symbol ${wl}foo $wl-update_registry $wl/dev/null"
+	   AC_LINK_IFELSE(
+	     [AC_LANG_SOURCE(
+	        [AC_LANG_CASE([C], [[int foo (void) { return 0; }]],
+			      [C++], [[int foo (void) { return 0; }]],
+			      [Fortran 77], [[
+      subroutine foo
+      end]],
+			      [Fortran], [[
+      subroutine foo
+      end]])])],
+	      [lt_cv_irix_exported_symbol=yes],
+	      [lt_cv_irix_exported_symbol=no])
+           LDFLAGS=$save_LDFLAGS])
+	if test yes = "$lt_cv_irix_exported_symbol"; then
+          _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations $wl-exports_file $wl$export_symbols -o $lib'
+	fi
+      else
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -exports_file $export_symbols -o $lib'
+      fi
+      _LT_TAGVAR(archive_cmds_need_lc, $1)='no'
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+      _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+      _LT_TAGVAR(inherit_rpath, $1)=yes
+      _LT_TAGVAR(link_all_deplibs, $1)=yes
+      ;;
+
+    linux*)
+      case $cc_basename in
+      tcc*)
+	# Fabrice Bellard et al's Tiny C Compiler
+	_LT_TAGVAR(ld_shlibs, $1)=yes
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+	;;
+      esac
+      ;;
+
+    netbsd*)
+      if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+	_LT_TAGVAR(archive_cmds, $1)='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags'  # a.out
+      else
+	_LT_TAGVAR(archive_cmds, $1)='$LD -shared -o $lib $libobjs $deplibs $linker_flags'      # ELF
+      fi
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-R$libdir'
+      _LT_TAGVAR(hardcode_direct, $1)=yes
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    newsos6)
+      _LT_TAGVAR(archive_cmds, $1)='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      _LT_TAGVAR(hardcode_direct, $1)=yes
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+      _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    *nto* | *qnx*)
+      ;;
+
+    openbsd* | bitrig*)
+      if test -f /usr/libexec/ld.so; then
+	_LT_TAGVAR(hardcode_direct, $1)=yes
+	_LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+	_LT_TAGVAR(hardcode_direct_absolute, $1)=yes
+	if test -z "`echo __ELF__ | $CC -E - | $GREP __ELF__`"; then
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+	  _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags $wl-retain-symbols-file,$export_symbols'
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath,$libdir'
+	  _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-E'
+	else
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath,$libdir'
+	fi
+      else
+	_LT_TAGVAR(ld_shlibs, $1)=no
+      fi
+      ;;
+
+    os2*)
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+      _LT_TAGVAR(hardcode_minus_L, $1)=yes
+      _LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+      shrext_cmds=.dll
+      _LT_TAGVAR(archive_cmds, $1)='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	emxexp $libobjs | $SED /"_DLL_InitTerm"/d >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      _LT_TAGVAR(archive_expsym_cmds, $1)='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	prefix_cmds="$SED"~
+	if test EXPORTS = "`$SED 1q $export_symbols`"; then
+	  prefix_cmds="$prefix_cmds -e 1d";
+	fi~
+	prefix_cmds="$prefix_cmds -e \"s/^\(.*\)$/_\1/g\""~
+	cat $export_symbols | $prefix_cmds >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      _LT_TAGVAR(old_archive_From_new_cmds, $1)='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
+      _LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+      ;;
+
+    osf3*)
+      if test yes = "$GCC"; then
+	_LT_TAGVAR(allow_undefined_flag, $1)=' $wl-expect_unresolved $wl\*'
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared$allow_undefined_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+      else
+	_LT_TAGVAR(allow_undefined_flag, $1)=' -expect_unresolved \*'
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared$allow_undefined_flag $libobjs $deplibs $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+      fi
+      _LT_TAGVAR(archive_cmds_need_lc, $1)='no'
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+      _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+      ;;
+
+    osf4* | osf5*)	# as osf3* with the addition of -msym flag
+      if test yes = "$GCC"; then
+	_LT_TAGVAR(allow_undefined_flag, $1)=' $wl-expect_unresolved $wl\*'
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared$allow_undefined_flag $pic_flag $libobjs $deplibs $compiler_flags $wl-msym $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+	_LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+      else
+	_LT_TAGVAR(allow_undefined_flag, $1)=' -expect_unresolved \*'
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared$allow_undefined_flag $libobjs $deplibs $compiler_flags -msym -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='for i in `cat $export_symbols`; do printf "%s %s\\n" -exported_symbol "\$i" >> $lib.exp; done; printf "%s\\n" "-hidden">> $lib.exp~
+          $CC -shared$allow_undefined_flag $wl-input $wl$lib.exp $compiler_flags $libobjs $deplibs -soname $soname `test -n "$verstring" && $ECHO "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib~$RM $lib.exp'
+
+	# Both c and cxx compiler support -rpath directly
+	_LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-rpath $libdir'
+      fi
+      _LT_TAGVAR(archive_cmds_need_lc, $1)='no'
+      _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+      ;;
+
+    solaris*)
+      _LT_TAGVAR(no_undefined_flag, $1)=' -z defs'
+      if test yes = "$GCC"; then
+	wlarc='$wl'
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $wl-z ${wl}text $wl-h $wl$soname -o $lib $libobjs $deplibs $compiler_flags'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+          $CC -shared $pic_flag $wl-z ${wl}text $wl-M $wl$lib.exp $wl-h $wl$soname -o $lib $libobjs $deplibs $compiler_flags~$RM $lib.exp'
+      else
+	case `$CC -V 2>&1` in
+	*"Compilers 5.0"*)
+	  wlarc=''
+	  _LT_TAGVAR(archive_cmds, $1)='$LD -G$allow_undefined_flag -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	  _LT_TAGVAR(archive_expsym_cmds, $1)='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+            $LD -G$allow_undefined_flag -M $lib.exp -h $soname -o $lib $libobjs $deplibs $linker_flags~$RM $lib.exp'
+	  ;;
+	*)
+	  wlarc='$wl'
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -G$allow_undefined_flag -h $soname -o $lib $libobjs $deplibs $compiler_flags'
+	  _LT_TAGVAR(archive_expsym_cmds, $1)='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+            $CC -G$allow_undefined_flag -M $lib.exp -h $soname -o $lib $libobjs $deplibs $compiler_flags~$RM $lib.exp'
+	  ;;
+	esac
+      fi
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-R$libdir'
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      case $host_os in
+      solaris2.[[0-5]] | solaris2.[[0-5]].*) ;;
+      *)
+	# The compiler driver will combine and reorder linker options,
+	# but understands '-z linker_flag'.  GCC discards it without '$wl',
+	# but is careful enough not to reorder.
+	# Supported since Solaris 2.6 (maybe 2.5.1?)
+	if test yes = "$GCC"; then
+	  _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl-z ${wl}allextract$convenience $wl-z ${wl}defaultextract'
+	else
+	  _LT_TAGVAR(whole_archive_flag_spec, $1)='-z allextract$convenience -z defaultextract'
+	fi
+	;;
+      esac
+      _LT_TAGVAR(link_all_deplibs, $1)=yes
+      ;;
+
+    sunos4*)
+      if test sequent = "$host_vendor"; then
+	# Use $CC to link under sequent, because it throws in some extra .o
+	# files that make .init and .fini sections work.
+	_LT_TAGVAR(archive_cmds, $1)='$CC -G $wl-h $soname -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	_LT_TAGVAR(archive_cmds, $1)='$LD -assert pure-text -Bstatic -o $lib $libobjs $deplibs $linker_flags'
+      fi
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+      _LT_TAGVAR(hardcode_direct, $1)=yes
+      _LT_TAGVAR(hardcode_minus_L, $1)=yes
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    sysv4)
+      case $host_vendor in
+	sni)
+	  _LT_TAGVAR(archive_cmds, $1)='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	  _LT_TAGVAR(hardcode_direct, $1)=yes # is this really true???
+	;;
+	siemens)
+	  ## LD is ld it makes a PLAMLIB
+	  ## CC just makes a GrossModule.
+	  _LT_TAGVAR(archive_cmds, $1)='$LD -G -o $lib $libobjs $deplibs $linker_flags'
+	  _LT_TAGVAR(reload_cmds, $1)='$CC -r -o $output$reload_objs'
+	  _LT_TAGVAR(hardcode_direct, $1)=no
+        ;;
+	motorola)
+	  _LT_TAGVAR(archive_cmds, $1)='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	  _LT_TAGVAR(hardcode_direct, $1)=no #Motorola manual says yes, but my tests say they lie
+	;;
+      esac
+      runpath_var='LD_RUN_PATH'
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    sysv4.3*)
+      _LT_TAGVAR(archive_cmds, $1)='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      _LT_TAGVAR(export_dynamic_flag_spec, $1)='-Bexport'
+      ;;
+
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	_LT_TAGVAR(archive_cmds, $1)='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	_LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+	runpath_var=LD_RUN_PATH
+	hardcode_runpath_var=yes
+	_LT_TAGVAR(ld_shlibs, $1)=yes
+      fi
+      ;;
+
+    sysv4*uw2* | sysv5OpenUNIX* | sysv5UnixWare7.[[01]].[[10]]* | unixware7* | sco3.2v5.0.[[024]]*)
+      _LT_TAGVAR(no_undefined_flag, $1)='$wl-z,text'
+      _LT_TAGVAR(archive_cmds_need_lc, $1)=no
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      runpath_var='LD_RUN_PATH'
+
+      if test yes = "$GCC"; then
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	_LT_TAGVAR(archive_cmds, $1)='$CC -G $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -G $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      fi
+      ;;
+
+    sysv5* | sco3.2v5* | sco5v6*)
+      # Note: We CANNOT use -z defs as we might desire, because we do not
+      # link with -lc, and that would cause any symbols used from libc to
+      # always be unresolved, which means just about no library would
+      # ever link correctly.  If we're not using GNU ld we use -z text
+      # though, which does catch some bad symbols but isn't as heavy-handed
+      # as -z defs.
+      _LT_TAGVAR(no_undefined_flag, $1)='$wl-z,text'
+      _LT_TAGVAR(allow_undefined_flag, $1)='$wl-z,nodefs'
+      _LT_TAGVAR(archive_cmds_need_lc, $1)=no
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-R,$libdir'
+      _LT_TAGVAR(hardcode_libdir_separator, $1)=':'
+      _LT_TAGVAR(link_all_deplibs, $1)=yes
+      _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-Bexport'
+      runpath_var='LD_RUN_PATH'
+
+      if test yes = "$GCC"; then
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	_LT_TAGVAR(archive_cmds, $1)='$CC -G $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -G $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      fi
+      ;;
+
+    uts4*)
+      _LT_TAGVAR(archive_cmds, $1)='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      ;;
+
+    *)
+      _LT_TAGVAR(ld_shlibs, $1)=no
+      ;;
+    esac
+
+    if test sni = "$host_vendor"; then
+      case $host in
+      sysv4 | sysv4.2uw2* | sysv4.3* | sysv5*)
+	_LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-Blargedynsym'
+	;;
+      esac
+    fi
+  fi
+])
+AC_MSG_RESULT([$_LT_TAGVAR(ld_shlibs, $1)])
+test no = "$_LT_TAGVAR(ld_shlibs, $1)" && can_build_shared=no
+
+_LT_TAGVAR(with_gnu_ld, $1)=$with_gnu_ld
+
+_LT_DECL([], [libext], [0], [Old archive suffix (normally "a")])dnl
+_LT_DECL([], [shrext_cmds], [1], [Shared library suffix (normally ".so")])dnl
+_LT_DECL([], [extract_expsyms_cmds], [2],
+    [The commands to extract the exported symbol list from a shared archive])
+
+#
+# Do we need to explicitly link libc?
+#
+case "x$_LT_TAGVAR(archive_cmds_need_lc, $1)" in
+x|xyes)
+  # Assume -lc should be added
+  _LT_TAGVAR(archive_cmds_need_lc, $1)=yes
+
+  if test yes,yes = "$GCC,$enable_shared"; then
+    case $_LT_TAGVAR(archive_cmds, $1) in
+    *'~'*)
+      # FIXME: we may have to deal with multi-command sequences.
+      ;;
+    '$CC '*)
+      # Test whether the compiler implicitly links with -lc since on some
+      # systems, -lgcc has to come before -lc. If gcc already passes -lc
+      # to ld, don't add -lc before -lgcc.
+      AC_CACHE_CHECK([whether -lc should be explicitly linked in],
+	[lt_cv_]_LT_TAGVAR(archive_cmds_need_lc, $1),
+	[$RM conftest*
+	echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+
+	if AC_TRY_EVAL(ac_compile) 2>conftest.err; then
+	  soname=conftest
+	  lib=conftest
+	  libobjs=conftest.$ac_objext
+	  deplibs=
+	  wl=$_LT_TAGVAR(lt_prog_compiler_wl, $1)
+	  pic_flag=$_LT_TAGVAR(lt_prog_compiler_pic, $1)
+	  compiler_flags=-v
+	  linker_flags=-v
+	  verstring=
+	  output_objdir=.
+	  libname=conftest
+	  lt_save_allow_undefined_flag=$_LT_TAGVAR(allow_undefined_flag, $1)
+	  _LT_TAGVAR(allow_undefined_flag, $1)=
+	  if AC_TRY_EVAL(_LT_TAGVAR(archive_cmds, $1) 2\>\&1 \| $GREP \" -lc \" \>/dev/null 2\>\&1)
+	  then
+	    lt_cv_[]_LT_TAGVAR(archive_cmds_need_lc, $1)=no
+	  else
+	    lt_cv_[]_LT_TAGVAR(archive_cmds_need_lc, $1)=yes
+	  fi
+	  _LT_TAGVAR(allow_undefined_flag, $1)=$lt_save_allow_undefined_flag
+	else
+	  cat conftest.err 1>&5
+	fi
+	$RM conftest*
+	])
+      _LT_TAGVAR(archive_cmds_need_lc, $1)=$lt_cv_[]_LT_TAGVAR(archive_cmds_need_lc, $1)
+      ;;
+    esac
+  fi
+  ;;
+esac
+
+_LT_TAGDECL([build_libtool_need_lc], [archive_cmds_need_lc], [0],
+    [Whether or not to add -lc for building shared libraries])
+_LT_TAGDECL([allow_libtool_libs_with_static_runtimes],
+    [enable_shared_with_static_runtimes], [0],
+    [Whether or not to disallow shared libs when runtime libs are static])
+_LT_TAGDECL([], [export_dynamic_flag_spec], [1],
+    [Compiler flag to allow reflexive dlopens])
+_LT_TAGDECL([], [whole_archive_flag_spec], [1],
+    [Compiler flag to generate shared objects directly from archives])
+_LT_TAGDECL([], [compiler_needs_object], [1],
+    [Whether the compiler copes with passing no objects directly])
+_LT_TAGDECL([], [old_archive_from_new_cmds], [2],
+    [Create an old-style archive from a shared archive])
+_LT_TAGDECL([], [old_archive_from_expsyms_cmds], [2],
+    [Create a temporary old-style archive to link instead of a shared archive])
+_LT_TAGDECL([], [archive_cmds], [2], [Commands used to build a shared archive])
+_LT_TAGDECL([], [archive_expsym_cmds], [2])
+_LT_TAGDECL([], [module_cmds], [2],
+    [Commands used to build a loadable module if different from building
+    a shared archive.])
+_LT_TAGDECL([], [module_expsym_cmds], [2])
+_LT_TAGDECL([], [with_gnu_ld], [1],
+    [Whether we are building with GNU ld or not])
+_LT_TAGDECL([], [allow_undefined_flag], [1],
+    [Flag that allows shared libraries with undefined symbols to be built])
+_LT_TAGDECL([], [no_undefined_flag], [1],
+    [Flag that enforces no undefined symbols])
+_LT_TAGDECL([], [hardcode_libdir_flag_spec], [1],
+    [Flag to hardcode $libdir into a binary during linking.
+    This must work even if $libdir does not exist])
+_LT_TAGDECL([], [hardcode_libdir_separator], [1],
+    [Whether we need a single "-rpath" flag with a separated argument])
+_LT_TAGDECL([], [hardcode_direct], [0],
+    [Set to "yes" if using DIR/libNAME$shared_ext during linking hardcodes
+    DIR into the resulting binary])
+_LT_TAGDECL([], [hardcode_direct_absolute], [0],
+    [Set to "yes" if using DIR/libNAME$shared_ext during linking hardcodes
+    DIR into the resulting binary and the resulting library dependency is
+    "absolute", i.e impossible to change by setting $shlibpath_var if the
+    library is relocated])
+_LT_TAGDECL([], [hardcode_minus_L], [0],
+    [Set to "yes" if using the -LDIR flag during linking hardcodes DIR
+    into the resulting binary])
+_LT_TAGDECL([], [hardcode_shlibpath_var], [0],
+    [Set to "yes" if using SHLIBPATH_VAR=DIR during linking hardcodes DIR
+    into the resulting binary])
+_LT_TAGDECL([], [hardcode_automatic], [0],
+    [Set to "yes" if building a shared library automatically hardcodes DIR
+    into the library and all subsequent libraries and executables linked
+    against it])
+_LT_TAGDECL([], [inherit_rpath], [0],
+    [Set to yes if linker adds runtime paths of dependent libraries
+    to runtime path list])
+_LT_TAGDECL([], [link_all_deplibs], [0],
+    [Whether libtool must link a program against all its dependency libraries])
+_LT_TAGDECL([], [always_export_symbols], [0],
+    [Set to "yes" if exported symbols are required])
+_LT_TAGDECL([], [export_symbols_cmds], [2],
+    [The commands to list exported symbols])
+_LT_TAGDECL([], [exclude_expsyms], [1],
+    [Symbols that should not be listed in the preloaded symbols])
+_LT_TAGDECL([], [include_expsyms], [1],
+    [Symbols that must always be exported])
+_LT_TAGDECL([], [prelink_cmds], [2],
+    [Commands necessary for linking programs (against libraries) with templates])
+_LT_TAGDECL([], [postlink_cmds], [2],
+    [Commands necessary for finishing linking programs])
+_LT_TAGDECL([], [file_list_spec], [1],
+    [Specify filename containing input files])
+dnl FIXME: Not yet implemented
+dnl _LT_TAGDECL([], [thread_safe_flag_spec], [1],
+dnl    [Compiler flag to generate thread safe objects])
+])# _LT_LINKER_SHLIBS
+
+
+# _LT_LANG_C_CONFIG([TAG])
+# ------------------------
+# Ensure that the configuration variables for a C compiler are suitably
+# defined.  These variables are subsequently used by _LT_CONFIG to write
+# the compiler configuration to 'libtool'.
+m4_defun([_LT_LANG_C_CONFIG],
+[m4_require([_LT_DECL_EGREP])dnl
+lt_save_CC=$CC
+AC_LANG_PUSH(C)
+
+# Source file extension for C test sources.
+ac_ext=c
+
+# Object file extension for compiled C test sources.
+objext=o
+_LT_TAGVAR(objext, $1)=$objext
+
+# Code to be used in simple compile tests
+lt_simple_compile_test_code="int some_variable = 0;"
+
+# Code to be used in simple link tests
+lt_simple_link_test_code='int main(){return(0);}'
+
+_LT_TAG_COMPILER
+# Save the default compiler, since it gets overwritten when the other
+# tags are being tested, and _LT_TAGVAR(compiler, []) is a NOP.
+compiler_DEFAULT=$CC
+
+# save warnings/boilerplate of simple test code
+_LT_COMPILER_BOILERPLATE
+_LT_LINKER_BOILERPLATE
+
+## CAVEAT EMPTOR:
+## There is no encapsulation within the following macros, do not change
+## the running order or otherwise move them around unless you know exactly
+## what you are doing...
+if test -n "$compiler"; then
+  _LT_COMPILER_NO_RTTI($1)
+  _LT_COMPILER_PIC($1)
+  _LT_COMPILER_C_O($1)
+  _LT_COMPILER_FILE_LOCKS($1)
+  _LT_LINKER_SHLIBS($1)
+  _LT_SYS_DYNAMIC_LINKER($1)
+  _LT_LINKER_HARDCODE_LIBPATH($1)
+  LT_SYS_DLOPEN_SELF
+  _LT_CMD_STRIPLIB
+
+  # Report what library types will actually be built
+  AC_MSG_CHECKING([if libtool supports shared libraries])
+  AC_MSG_RESULT([$can_build_shared])
+
+  AC_MSG_CHECKING([whether to build shared libraries])
+  test no = "$can_build_shared" && enable_shared=no
+
+  # On AIX, shared libraries and static libraries use the same namespace, and
+  # are all built from PIC.
+  case $host_os in
+  aix3*)
+    test yes = "$enable_shared" && enable_static=no
+    if test -n "$RANLIB"; then
+      archive_cmds="$archive_cmds~\$RANLIB \$lib"
+      postinstall_cmds='$RANLIB $lib'
+    fi
+    ;;
+
+  aix[[4-9]]*)
+    if test ia64 != "$host_cpu"; then
+      case $enable_shared,$with_aix_soname,$aix_use_runtimelinking in
+      yes,aix,yes) ;;			# shared object as lib.so file only
+      yes,svr4,*) ;;			# shared object as lib.so archive member only
+      yes,*) enable_static=no ;;	# shared object in lib.a archive as well
+      esac
+    fi
+    ;;
+  esac
+  AC_MSG_RESULT([$enable_shared])
+
+  AC_MSG_CHECKING([whether to build static libraries])
+  # Make sure either enable_shared or enable_static is yes.
+  test yes = "$enable_shared" || enable_static=yes
+  AC_MSG_RESULT([$enable_static])
+
+  _LT_CONFIG($1)
+fi
+AC_LANG_POP
+CC=$lt_save_CC
+])# _LT_LANG_C_CONFIG
+
+
+# _LT_LANG_CXX_CONFIG([TAG])
+# --------------------------
+# Ensure that the configuration variables for a C++ compiler are suitably
+# defined.  These variables are subsequently used by _LT_CONFIG to write
+# the compiler configuration to 'libtool'.
+m4_defun([_LT_LANG_CXX_CONFIG],
+[m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+m4_require([_LT_DECL_EGREP])dnl
+m4_require([_LT_PATH_MANIFEST_TOOL])dnl
+if test -n "$CXX" && ( test no != "$CXX" &&
+    ( (test g++ = "$CXX" && `g++ -v >/dev/null 2>&1` ) ||
+    (test g++ != "$CXX"))); then
+  AC_PROG_CXXCPP
+else
+  _lt_caught_CXX_error=yes
+fi
+
+AC_LANG_PUSH(C++)
+_LT_TAGVAR(archive_cmds_need_lc, $1)=no
+_LT_TAGVAR(allow_undefined_flag, $1)=
+_LT_TAGVAR(always_export_symbols, $1)=no
+_LT_TAGVAR(archive_expsym_cmds, $1)=
+_LT_TAGVAR(compiler_needs_object, $1)=no
+_LT_TAGVAR(export_dynamic_flag_spec, $1)=
+_LT_TAGVAR(hardcode_direct, $1)=no
+_LT_TAGVAR(hardcode_direct_absolute, $1)=no
+_LT_TAGVAR(hardcode_libdir_flag_spec, $1)=
+_LT_TAGVAR(hardcode_libdir_separator, $1)=
+_LT_TAGVAR(hardcode_minus_L, $1)=no
+_LT_TAGVAR(hardcode_shlibpath_var, $1)=unsupported
+_LT_TAGVAR(hardcode_automatic, $1)=no
+_LT_TAGVAR(inherit_rpath, $1)=no
+_LT_TAGVAR(module_cmds, $1)=
+_LT_TAGVAR(module_expsym_cmds, $1)=
+_LT_TAGVAR(link_all_deplibs, $1)=unknown
+_LT_TAGVAR(old_archive_cmds, $1)=$old_archive_cmds
+_LT_TAGVAR(reload_flag, $1)=$reload_flag
+_LT_TAGVAR(reload_cmds, $1)=$reload_cmds
+_LT_TAGVAR(no_undefined_flag, $1)=
+_LT_TAGVAR(whole_archive_flag_spec, $1)=
+_LT_TAGVAR(enable_shared_with_static_runtimes, $1)=no
+
+# Source file extension for C++ test sources.
+ac_ext=cpp
+
+# Object file extension for compiled C++ test sources.
+objext=o
+_LT_TAGVAR(objext, $1)=$objext
+
+# No sense in running all these tests if we already determined that
+# the CXX compiler isn't working.  Some variables (like enable_shared)
+# are currently assumed to apply to all compilers on this platform,
+# and will be corrupted by setting them based on a non-working compiler.
+if test yes != "$_lt_caught_CXX_error"; then
+  # Code to be used in simple compile tests
+  lt_simple_compile_test_code="int some_variable = 0;"
+
+  # Code to be used in simple link tests
+  lt_simple_link_test_code='int main(int, char *[[]]) { return(0); }'
+
+  # ltmain only uses $CC for tagged configurations so make sure $CC is set.
+  _LT_TAG_COMPILER
+
+  # save warnings/boilerplate of simple test code
+  _LT_COMPILER_BOILERPLATE
+  _LT_LINKER_BOILERPLATE
+
+  # Allow CC to be a program name with arguments.
+  lt_save_CC=$CC
+  lt_save_CFLAGS=$CFLAGS
+  lt_save_LD=$LD
+  lt_save_GCC=$GCC
+  GCC=$GXX
+  lt_save_with_gnu_ld=$with_gnu_ld
+  lt_save_path_LD=$lt_cv_path_LD
+  if test -n "${lt_cv_prog_gnu_ldcxx+set}"; then
+    lt_cv_prog_gnu_ld=$lt_cv_prog_gnu_ldcxx
+  else
+    $as_unset lt_cv_prog_gnu_ld
+  fi
+  if test -n "${lt_cv_path_LDCXX+set}"; then
+    lt_cv_path_LD=$lt_cv_path_LDCXX
+  else
+    $as_unset lt_cv_path_LD
+  fi
+  test -z "${LDCXX+set}" || LD=$LDCXX
+  CC=${CXX-"c++"}
+  CFLAGS=$CXXFLAGS
+  compiler=$CC
+  _LT_TAGVAR(compiler, $1)=$CC
+  _LT_CC_BASENAME([$compiler])
+
+  if test -n "$compiler"; then
+    # We don't want -fno-exception when compiling C++ code, so set the
+    # no_builtin_flag separately
+    if test yes = "$GXX"; then
+      _LT_TAGVAR(lt_prog_compiler_no_builtin_flag, $1)=' -fno-builtin'
+    else
+      _LT_TAGVAR(lt_prog_compiler_no_builtin_flag, $1)=
+    fi
+
+    if test yes = "$GXX"; then
+      # Set up default GNU C++ configuration
+
+      LT_PATH_LD
+
+      # Check if GNU C++ uses GNU ld as the underlying linker, since the
+      # archiving commands below assume that GNU ld is being used.
+      if test yes = "$with_gnu_ld"; then
+        _LT_TAGVAR(archive_cmds, $1)='$CC $pic_flag -shared -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname -o $lib'
+        _LT_TAGVAR(archive_expsym_cmds, $1)='$CC $pic_flag -shared -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+
+        _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+        _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl--export-dynamic'
+
+        # If archive_cmds runs LD, not CC, wlarc should be empty
+        # XXX I think wlarc can be eliminated in ltcf-cxx, but I need to
+        #     investigate it a little bit more. (MM)
+        wlarc='$wl'
+
+        # ancient GNU ld didn't support --whole-archive et. al.
+        if eval "`$CC -print-prog-name=ld` --help 2>&1" |
+	  $GREP 'no-whole-archive' > /dev/null; then
+          _LT_TAGVAR(whole_archive_flag_spec, $1)=$wlarc'--whole-archive$convenience '$wlarc'--no-whole-archive'
+        else
+          _LT_TAGVAR(whole_archive_flag_spec, $1)=
+        fi
+      else
+        with_gnu_ld=no
+        wlarc=
+
+        # A generic and very simple default shared library creation
+        # command for GNU C++ for the case where it uses the native
+        # linker, instead of GNU ld.  If possible, this setting should
+        # overridden to take advantage of the native linker features on
+        # the platform it is being used on.
+        _LT_TAGVAR(archive_cmds, $1)='$CC -shared -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags -o $lib'
+      fi
+
+      # Commands to make compiler produce verbose output that lists
+      # what "hidden" libraries, object files and flags are used when
+      # linking a shared library.
+      output_verbose_link_cmd='$CC -shared $CFLAGS -v conftest.$objext 2>&1 | $GREP -v "^Configured with:" | $GREP "\-L"'
+
+    else
+      GXX=no
+      with_gnu_ld=no
+      wlarc=
+    fi
+
+    # PORTME: fill in a description of your system's C++ link characteristics
+    AC_MSG_CHECKING([whether the $compiler linker ($LD) supports shared libraries])
+    _LT_TAGVAR(ld_shlibs, $1)=yes
+    case $host_os in
+      aix3*)
+        # FIXME: insert proper C++ library support
+        _LT_TAGVAR(ld_shlibs, $1)=no
+        ;;
+      aix[[4-9]]*)
+        if test ia64 = "$host_cpu"; then
+          # On IA64, the linker does run time linking by default, so we don't
+          # have to do anything special.
+          aix_use_runtimelinking=no
+          exp_sym_flag='-Bexport'
+          no_entry_flag=
+        else
+          aix_use_runtimelinking=no
+
+          # Test if we are trying to use run time linking or normal
+          # AIX style linking. If -brtl is somewhere in LDFLAGS, we
+          # have runtime linking enabled, and use it for executables.
+          # For shared libraries, we enable/disable runtime linking
+          # depending on the kind of the shared library created -
+          # when "with_aix_soname,aix_use_runtimelinking" is:
+          # "aix,no"   lib.a(lib.so.V) shared, rtl:no,  for executables
+          # "aix,yes"  lib.so          shared, rtl:yes, for executables
+          #            lib.a           static archive
+          # "both,no"  lib.so.V(shr.o) shared, rtl:yes
+          #            lib.a(lib.so.V) shared, rtl:no,  for executables
+          # "both,yes" lib.so.V(shr.o) shared, rtl:yes, for executables
+          #            lib.a(lib.so.V) shared, rtl:no
+          # "svr4,*"   lib.so.V(shr.o) shared, rtl:yes, for executables
+          #            lib.a           static archive
+          case $host_os in aix4.[[23]]|aix4.[[23]].*|aix[[5-9]]*)
+	    for ld_flag in $LDFLAGS; do
+	      case $ld_flag in
+	      *-brtl*)
+	        aix_use_runtimelinking=yes
+	        break
+	        ;;
+	      esac
+	    done
+	    if test svr4,no = "$with_aix_soname,$aix_use_runtimelinking"; then
+	      # With aix-soname=svr4, we create the lib.so.V shared archives only,
+	      # so we don't have lib.a shared libs to link our executables.
+	      # We have to force runtime linking in this case.
+	      aix_use_runtimelinking=yes
+	      LDFLAGS="$LDFLAGS -Wl,-brtl"
+	    fi
+	    ;;
+          esac
+
+          exp_sym_flag='-bexport'
+          no_entry_flag='-bnoentry'
+        fi
+
+        # When large executables or shared objects are built, AIX ld can
+        # have problems creating the table of contents.  If linking a library
+        # or program results in "error TOC overflow" add -mminimal-toc to
+        # CXXFLAGS/CFLAGS for g++/gcc.  In the cases where that is not
+        # enough to fix the problem, add -Wl,-bbigtoc to LDFLAGS.
+
+        _LT_TAGVAR(archive_cmds, $1)=''
+        _LT_TAGVAR(hardcode_direct, $1)=yes
+        _LT_TAGVAR(hardcode_direct_absolute, $1)=yes
+        _LT_TAGVAR(hardcode_libdir_separator, $1)=':'
+        _LT_TAGVAR(link_all_deplibs, $1)=yes
+        _LT_TAGVAR(file_list_spec, $1)='$wl-f,'
+        case $with_aix_soname,$aix_use_runtimelinking in
+        aix,*) ;;	# no import file
+        svr4,* | *,yes) # use import file
+          # The Import File defines what to hardcode.
+          _LT_TAGVAR(hardcode_direct, $1)=no
+          _LT_TAGVAR(hardcode_direct_absolute, $1)=no
+          ;;
+        esac
+
+        if test yes = "$GXX"; then
+          case $host_os in aix4.[[012]]|aix4.[[012]].*)
+          # We only want to do this on AIX 4.2 and lower, the check
+          # below for broken collect2 doesn't work under 4.3+
+	  collect2name=`$CC -print-prog-name=collect2`
+	  if test -f "$collect2name" &&
+	     strings "$collect2name" | $GREP resolve_lib_name >/dev/null
+	  then
+	    # We have reworked collect2
+	    :
+	  else
+	    # We have old collect2
+	    _LT_TAGVAR(hardcode_direct, $1)=unsupported
+	    # It fails to find uninstalled libraries when the uninstalled
+	    # path is not listed in the libpath.  Setting hardcode_minus_L
+	    # to unsupported forces relinking
+	    _LT_TAGVAR(hardcode_minus_L, $1)=yes
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+	    _LT_TAGVAR(hardcode_libdir_separator, $1)=
+	  fi
+          esac
+          shared_flag='-shared'
+	  if test yes = "$aix_use_runtimelinking"; then
+	    shared_flag=$shared_flag' $wl-G'
+	  fi
+	  # Need to ensure runtime linking is disabled for the traditional
+	  # shared library, or the linker may eventually find shared libraries
+	  # /with/ Import File - we do not want to mix them.
+	  shared_flag_aix='-shared'
+	  shared_flag_svr4='-shared $wl-G'
+        else
+          # not using gcc
+          if test ia64 = "$host_cpu"; then
+	  # VisualAge C++, Version 5.5 for AIX 5L for IA-64, Beta 3 Release
+	  # chokes on -Wl,-G. The following line is correct:
+	  shared_flag='-G'
+          else
+	    if test yes = "$aix_use_runtimelinking"; then
+	      shared_flag='$wl-G'
+	    else
+	      shared_flag='$wl-bM:SRE'
+	    fi
+	    shared_flag_aix='$wl-bM:SRE'
+	    shared_flag_svr4='$wl-G'
+          fi
+        fi
+
+        _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-bexpall'
+        # It seems that -bexpall does not export symbols beginning with
+        # underscore (_), so it is better to generate a list of symbols to
+	# export.
+        _LT_TAGVAR(always_export_symbols, $1)=yes
+	if test aix,yes = "$with_aix_soname,$aix_use_runtimelinking"; then
+          # Warning - without using the other runtime loading flags (-brtl),
+          # -berok will link without error, but may produce a broken library.
+          # The "-G" linker flag allows undefined symbols.
+          _LT_TAGVAR(no_undefined_flag, $1)='-bernotok'
+          # Determine the default libpath from the value encoded in an empty
+          # executable.
+          _LT_SYS_MODULE_PATH_AIX([$1])
+          _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-blibpath:$libdir:'"$aix_libpath"
+
+          _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -o $output_objdir/$soname $libobjs $deplibs $wl'$no_entry_flag' $compiler_flags `if test -n "$allow_undefined_flag"; then func_echo_all "$wl$allow_undefined_flag"; else :; fi` $wl'$exp_sym_flag:\$export_symbols' '$shared_flag
+        else
+          if test ia64 = "$host_cpu"; then
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-R $libdir:/usr/lib:/lib'
+	    _LT_TAGVAR(allow_undefined_flag, $1)="-z nodefs"
+	    _LT_TAGVAR(archive_expsym_cmds, $1)="\$CC $shared_flag"' -o $output_objdir/$soname $libobjs $deplibs '"\$wl$no_entry_flag"' $compiler_flags $wl$allow_undefined_flag '"\$wl$exp_sym_flag:\$export_symbols"
+          else
+	    # Determine the default libpath from the value encoded in an
+	    # empty executable.
+	    _LT_SYS_MODULE_PATH_AIX([$1])
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-blibpath:$libdir:'"$aix_libpath"
+	    # Warning - without using the other run time loading flags,
+	    # -berok will link without error, but may produce a broken library.
+	    _LT_TAGVAR(no_undefined_flag, $1)=' $wl-bernotok'
+	    _LT_TAGVAR(allow_undefined_flag, $1)=' $wl-berok'
+	    if test yes = "$with_gnu_ld"; then
+	      # We only use this code for GNU lds that support --whole-archive.
+	      _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl--whole-archive$convenience $wl--no-whole-archive'
+	    else
+	      # Exported symbols can be pulled into shared objects from archives
+	      _LT_TAGVAR(whole_archive_flag_spec, $1)='$convenience'
+	    fi
+	    _LT_TAGVAR(archive_cmds_need_lc, $1)=yes
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='$RM -r $output_objdir/$realname.d~$MKDIR $output_objdir/$realname.d'
+	    # -brtl affects multiple linker settings, -berok does not and is overridden later
+	    compiler_flags_filtered='`func_echo_all "$compiler_flags " | $SED -e "s%-brtl\\([[, ]]\\)%-berok\\1%g"`'
+	    if test svr4 != "$with_aix_soname"; then
+	      # This is similar to how AIX traditionally builds its shared
+	      # libraries. Need -bnortl late, we may have -brtl in LDFLAGS.
+	      _LT_TAGVAR(archive_expsym_cmds, $1)="$_LT_TAGVAR(archive_expsym_cmds, $1)"'~$CC '$shared_flag_aix' -o $output_objdir/$realname.d/$soname $libobjs $deplibs $wl-bnoentry '$compiler_flags_filtered'$wl-bE:$export_symbols$allow_undefined_flag~$AR $AR_FLAGS $output_objdir/$libname$release.a $output_objdir/$realname.d/$soname'
+	    fi
+	    if test aix != "$with_aix_soname"; then
+	      _LT_TAGVAR(archive_expsym_cmds, $1)="$_LT_TAGVAR(archive_expsym_cmds, $1)"'~$CC '$shared_flag_svr4' -o $output_objdir/$realname.d/$shared_archive_member_spec.o $libobjs $deplibs $wl-bnoentry '$compiler_flags_filtered'$wl-bE:$export_symbols$allow_undefined_flag~$STRIP -e $output_objdir/$realname.d/$shared_archive_member_spec.o~( func_echo_all "#! $soname($shared_archive_member_spec.o)"; if test shr_64 = "$shared_archive_member_spec"; then func_echo_all "# 64"; else func_echo_all "# 32"; fi; cat $export_symbols ) > $output_objdir/$realname.d/$shared_archive_member_spec.imp~$AR $AR_FLAGS $output_objdir/$soname $output_objdir/$realname.d/$shared_archive_member_spec.o $output_objdir/$realname.d/$shared_archive_member_spec.imp'
+	    else
+	      # used by -dlpreopen to get the symbols
+	      _LT_TAGVAR(archive_expsym_cmds, $1)="$_LT_TAGVAR(archive_expsym_cmds, $1)"'~$MV  $output_objdir/$realname.d/$soname $output_objdir'
+	    fi
+	    _LT_TAGVAR(archive_expsym_cmds, $1)="$_LT_TAGVAR(archive_expsym_cmds, $1)"'~$RM -r $output_objdir/$realname.d'
+          fi
+        fi
+        ;;
+
+      beos*)
+	if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	  _LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+	  # Joseph Beckenbach <jrb3@best.com> says some releases of gcc
+	  # support --undefined.  This deserves some investigation.  FIXME
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -nostart $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	else
+	  _LT_TAGVAR(ld_shlibs, $1)=no
+	fi
+	;;
+
+      chorus*)
+        case $cc_basename in
+          *)
+	  # FIXME: insert proper C++ library support
+	  _LT_TAGVAR(ld_shlibs, $1)=no
+	  ;;
+        esac
+        ;;
+
+      cygwin* | mingw* | pw32* | cegcc*)
+	case $GXX,$cc_basename in
+	,cl* | no,cl*)
+	  # Native MSVC
+	  # hardcode_libdir_flag_spec is actually meaningless, as there is
+	  # no search path for DLLs.
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)=' '
+	  _LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+	  _LT_TAGVAR(always_export_symbols, $1)=yes
+	  _LT_TAGVAR(file_list_spec, $1)='@'
+	  # Tell ltmain to make .lib files, not .a files.
+	  libext=lib
+	  # Tell ltmain to make .dll files, not .so files.
+	  shrext_cmds=.dll
+	  # FIXME: Setting linknames here is a bad hack.
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -o $output_objdir/$soname $libobjs $compiler_flags $deplibs -Wl,-DLL,-IMPLIB:"$tool_output_objdir$libname.dll.lib"~linknames='
+	  _LT_TAGVAR(archive_expsym_cmds, $1)='if _LT_DLL_DEF_P([$export_symbols]); then
+              cp "$export_symbols" "$output_objdir/$soname.def";
+              echo "$tool_output_objdir$soname.def" > "$output_objdir/$soname.exp";
+            else
+              $SED -e '\''s/^/-link -EXPORT:/'\'' < $export_symbols > $output_objdir/$soname.exp;
+            fi~
+            $CC -o $tool_output_objdir$soname $libobjs $compiler_flags $deplibs "@$tool_output_objdir$soname.exp" -Wl,-DLL,-IMPLIB:"$tool_output_objdir$libname.dll.lib"~
+            linknames='
+	  # The linker will not automatically build a static lib if we build a DLL.
+	  # _LT_TAGVAR(old_archive_from_new_cmds, $1)='true'
+	  _LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+	  # Don't use ranlib
+	  _LT_TAGVAR(old_postinstall_cmds, $1)='chmod 644 $oldlib'
+	  _LT_TAGVAR(postlink_cmds, $1)='lt_outputfile="@OUTPUT@"~
+            lt_tool_outputfile="@TOOL_OUTPUT@"~
+            case $lt_outputfile in
+              *.exe|*.EXE) ;;
+              *)
+                lt_outputfile=$lt_outputfile.exe
+                lt_tool_outputfile=$lt_tool_outputfile.exe
+                ;;
+            esac~
+            func_to_tool_file "$lt_outputfile"~
+            if test : != "$MANIFEST_TOOL" && test -f "$lt_outputfile.manifest"; then
+              $MANIFEST_TOOL -manifest "$lt_tool_outputfile.manifest" -outputresource:"$lt_tool_outputfile" || exit 1;
+              $RM "$lt_outputfile.manifest";
+            fi'
+	  ;;
+	*)
+	  # g++
+	  # _LT_TAGVAR(hardcode_libdir_flag_spec, $1) is actually meaningless,
+	  # as there is no search path for DLLs.
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+	  _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl--export-all-symbols'
+	  _LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+	  _LT_TAGVAR(always_export_symbols, $1)=no
+	  _LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+
+	  if $LD --help 2>&1 | $GREP 'auto-import' > /dev/null; then
+	    _LT_TAGVAR(archive_cmds, $1)='$CC -shared -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
+	    # If the export-symbols file already is a .def file, use it as
+	    # is; otherwise, prepend EXPORTS...
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='if _LT_DLL_DEF_P([$export_symbols]); then
+              cp $export_symbols $output_objdir/$soname.def;
+            else
+              echo EXPORTS > $output_objdir/$soname.def;
+              cat $export_symbols >> $output_objdir/$soname.def;
+            fi~
+            $CC -shared -nostdlib $output_objdir/$soname.def $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
+	  else
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	  fi
+	  ;;
+	esac
+	;;
+      darwin* | rhapsody*)
+        _LT_DARWIN_LINKER_FEATURES($1)
+	;;
+
+      os2*)
+	_LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
+	_LT_TAGVAR(hardcode_minus_L, $1)=yes
+	_LT_TAGVAR(allow_undefined_flag, $1)=unsupported
+	shrext_cmds=.dll
+	_LT_TAGVAR(archive_cmds, $1)='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	  $ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	  $ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	  $ECHO EXPORTS >> $output_objdir/$libname.def~
+	  emxexp $libobjs | $SED /"_DLL_InitTerm"/d >> $output_objdir/$libname.def~
+	  $CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	  emximp -o $lib $output_objdir/$libname.def'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	  $ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	  $ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	  $ECHO EXPORTS >> $output_objdir/$libname.def~
+	  prefix_cmds="$SED"~
+	  if test EXPORTS = "`$SED 1q $export_symbols`"; then
+	    prefix_cmds="$prefix_cmds -e 1d";
+	  fi~
+	  prefix_cmds="$prefix_cmds -e \"s/^\(.*\)$/_\1/g\""~
+	  cat $export_symbols | $prefix_cmds >> $output_objdir/$libname.def~
+	  $CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	  emximp -o $lib $output_objdir/$libname.def'
+	_LT_TAGVAR(old_archive_From_new_cmds, $1)='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
+	_LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+	;;
+
+      dgux*)
+        case $cc_basename in
+          ec++*)
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+          ghcx*)
+	    # Green Hills C++ Compiler
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+          *)
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+        esac
+        ;;
+
+      freebsd2.*)
+        # C++ shared libraries reported to be fairly broken before
+	# switch to ELF
+        _LT_TAGVAR(ld_shlibs, $1)=no
+        ;;
+
+      freebsd-elf*)
+        _LT_TAGVAR(archive_cmds_need_lc, $1)=no
+        ;;
+
+      freebsd* | dragonfly*)
+        # FreeBSD 3 and later use GNU C++ and GNU ld with standard ELF
+        # conventions
+        _LT_TAGVAR(ld_shlibs, $1)=yes
+        ;;
+
+      haiku*)
+        _LT_TAGVAR(archive_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+        _LT_TAGVAR(link_all_deplibs, $1)=yes
+        ;;
+
+      hpux9*)
+        _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl+b $wl$libdir'
+        _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+        _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-E'
+        _LT_TAGVAR(hardcode_direct, $1)=yes
+        _LT_TAGVAR(hardcode_minus_L, $1)=yes # Not in the search PATH,
+				             # but as the default
+				             # location of the library.
+
+        case $cc_basename in
+          CC*)
+            # FIXME: insert proper C++ library support
+            _LT_TAGVAR(ld_shlibs, $1)=no
+            ;;
+          aCC*)
+            _LT_TAGVAR(archive_cmds, $1)='$RM $output_objdir/$soname~$CC -b $wl+b $wl$install_libdir -o $output_objdir/$soname $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags~test "x$output_objdir/$soname" = "x$lib" || mv $output_objdir/$soname $lib'
+            # Commands to make compiler produce verbose output that lists
+            # what "hidden" libraries, object files and flags are used when
+            # linking a shared library.
+            #
+            # There doesn't appear to be a way to prevent this compiler from
+            # explicitly linking system object files so we need to strip them
+            # from the output so that they don't get included in the library
+            # dependencies.
+            output_verbose_link_cmd='templist=`($CC -b $CFLAGS -v conftest.$objext 2>&1) | $EGREP "\-L"`; list= ; for z in $templist; do case $z in conftest.$objext) list="$list $z";; *.$objext);; *) list="$list $z";;esac; done; func_echo_all "$list"'
+            ;;
+          *)
+            if test yes = "$GXX"; then
+              _LT_TAGVAR(archive_cmds, $1)='$RM $output_objdir/$soname~$CC -shared -nostdlib $pic_flag $wl+b $wl$install_libdir -o $output_objdir/$soname $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags~test "x$output_objdir/$soname" = "x$lib" || mv $output_objdir/$soname $lib'
+            else
+              # FIXME: insert proper C++ library support
+              _LT_TAGVAR(ld_shlibs, $1)=no
+            fi
+            ;;
+        esac
+        ;;
+
+      hpux10*|hpux11*)
+        if test no = "$with_gnu_ld"; then
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl+b $wl$libdir'
+	  _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+
+          case $host_cpu in
+            hppa*64*|ia64*)
+              ;;
+            *)
+	      _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-E'
+              ;;
+          esac
+        fi
+        case $host_cpu in
+          hppa*64*|ia64*)
+            _LT_TAGVAR(hardcode_direct, $1)=no
+            _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+            ;;
+          *)
+            _LT_TAGVAR(hardcode_direct, $1)=yes
+            _LT_TAGVAR(hardcode_direct_absolute, $1)=yes
+            _LT_TAGVAR(hardcode_minus_L, $1)=yes # Not in the search PATH,
+					         # but as the default
+					         # location of the library.
+            ;;
+        esac
+
+        case $cc_basename in
+          CC*)
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+          aCC*)
+	    case $host_cpu in
+	      hppa*64*)
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -b $wl+h $wl$soname -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags'
+	        ;;
+	      ia64*)
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -b $wl+h $wl$soname $wl+nodefaultrpath -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags'
+	        ;;
+	      *)
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -b $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags'
+	        ;;
+	    esac
+	    # Commands to make compiler produce verbose output that lists
+	    # what "hidden" libraries, object files and flags are used when
+	    # linking a shared library.
+	    #
+	    # There doesn't appear to be a way to prevent this compiler from
+	    # explicitly linking system object files so we need to strip them
+	    # from the output so that they don't get included in the library
+	    # dependencies.
+	    output_verbose_link_cmd='templist=`($CC -b $CFLAGS -v conftest.$objext 2>&1) | $GREP "\-L"`; list= ; for z in $templist; do case $z in conftest.$objext) list="$list $z";; *.$objext);; *) list="$list $z";;esac; done; func_echo_all "$list"'
+	    ;;
+          *)
+	    if test yes = "$GXX"; then
+	      if test no = "$with_gnu_ld"; then
+	        case $host_cpu in
+	          hppa*64*)
+	            _LT_TAGVAR(archive_cmds, $1)='$CC -shared -nostdlib -fPIC $wl+h $wl$soname -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags'
+	            ;;
+	          ia64*)
+	            _LT_TAGVAR(archive_cmds, $1)='$CC -shared -nostdlib $pic_flag $wl+h $wl$soname $wl+nodefaultrpath -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags'
+	            ;;
+	          *)
+	            _LT_TAGVAR(archive_cmds, $1)='$CC -shared -nostdlib $pic_flag $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags'
+	            ;;
+	        esac
+	      fi
+	    else
+	      # FIXME: insert proper C++ library support
+	      _LT_TAGVAR(ld_shlibs, $1)=no
+	    fi
+	    ;;
+        esac
+        ;;
+
+      interix[[3-9]]*)
+	_LT_TAGVAR(hardcode_direct, $1)=no
+	_LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+	_LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath,$libdir'
+	_LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-E'
+	# Hack: On Interix 3.x, we cannot compile PIC because of a broken gcc.
+	# Instead, shared libraries are loaded at an image base (0x10000000 by
+	# default) and relocated if they conflict, which is a slow very memory
+	# consuming and fragmenting process.  To avoid this, we pick a random,
+	# 256 KiB-aligned image base between 0x50000000 and 0x6FFC0000 at link
+	# time.  Moving up from 0x10000000 also allows more sbrk(2) space.
+	_LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-h,$soname $wl--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
+	_LT_TAGVAR(archive_expsym_cmds, $1)='sed "s|^|_|" $export_symbols >$output_objdir/$soname.expsym~$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-h,$soname $wl--retain-symbols-file,$output_objdir/$soname.expsym $wl--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
+	;;
+      irix5* | irix6*)
+        case $cc_basename in
+          CC*)
+	    # SGI C++
+	    _LT_TAGVAR(archive_cmds, $1)='$CC -shared -all -multigot $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+
+	    # Archives containing C++ object files must be created using
+	    # "CC -ar", where "CC" is the IRIX C++ compiler.  This is
+	    # necessary to make sure instantiated templates are included
+	    # in the archive.
+	    _LT_TAGVAR(old_archive_cmds, $1)='$CC -ar -WR,-u -o $oldlib $oldobjs'
+	    ;;
+          *)
+	    if test yes = "$GXX"; then
+	      if test no = "$with_gnu_ld"; then
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+	      else
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` -o $lib'
+	      fi
+	    fi
+	    _LT_TAGVAR(link_all_deplibs, $1)=yes
+	    ;;
+        esac
+        _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+        _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+        _LT_TAGVAR(inherit_rpath, $1)=yes
+        ;;
+
+      linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+        case $cc_basename in
+          KCC*)
+	    # Kuck and Associates, Inc. (KAI) C++ Compiler
+
+	    # KCC will only create a shared library if the output file
+	    # ends with ".so" (or ".sl" for HP-UX), so rename the library
+	    # to its proper name (with version) after linking.
+	    _LT_TAGVAR(archive_cmds, $1)='tempext=`echo $shared_ext | $SED -e '\''s/\([[^()0-9A-Za-z{}]]\)/\\\\\1/g'\''`; templib=`echo $lib | $SED -e "s/\$tempext\..*/.so/"`; $CC $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags --soname $soname -o \$templib; mv \$templib $lib'
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='tempext=`echo $shared_ext | $SED -e '\''s/\([[^()0-9A-Za-z{}]]\)/\\\\\1/g'\''`; templib=`echo $lib | $SED -e "s/\$tempext\..*/.so/"`; $CC $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags --soname $soname -o \$templib $wl-retain-symbols-file,$export_symbols; mv \$templib $lib'
+	    # Commands to make compiler produce verbose output that lists
+	    # what "hidden" libraries, object files and flags are used when
+	    # linking a shared library.
+	    #
+	    # There doesn't appear to be a way to prevent this compiler from
+	    # explicitly linking system object files so we need to strip them
+	    # from the output so that they don't get included in the library
+	    # dependencies.
+	    output_verbose_link_cmd='templist=`$CC $CFLAGS -v conftest.$objext -o libconftest$shared_ext 2>&1 | $GREP "ld"`; rm -f libconftest$shared_ext; list= ; for z in $templist; do case $z in conftest.$objext) list="$list $z";; *.$objext);; *) list="$list $z";;esac; done; func_echo_all "$list"'
+
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath,$libdir'
+	    _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl--export-dynamic'
+
+	    # Archives containing C++ object files must be created using
+	    # "CC -Bstatic", where "CC" is the KAI C++ compiler.
+	    _LT_TAGVAR(old_archive_cmds, $1)='$CC -Bstatic -o $oldlib $oldobjs'
+	    ;;
+	  icpc* | ecpc* )
+	    # Intel C++
+	    with_gnu_ld=yes
+	    # version 8.0 and above of icpc choke on multiply defined symbols
+	    # if we add $predep_objects and $postdep_objects, however 7.1 and
+	    # earlier do not add the objects themselves.
+	    case `$CC -V 2>&1` in
+	      *"Version 7."*)
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -shared $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname -o $lib'
+		_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+		;;
+	      *)  # Version 8.0 or newer
+	        tmp_idyn=
+	        case $host_cpu in
+		  ia64*) tmp_idyn=' -i_dynamic';;
+		esac
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -shared'"$tmp_idyn"' $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+		_LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared'"$tmp_idyn"' $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+		;;
+	    esac
+	    _LT_TAGVAR(archive_cmds_need_lc, $1)=no
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath,$libdir'
+	    _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl--export-dynamic'
+	    _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl--whole-archive$convenience $wl--no-whole-archive'
+	    ;;
+          pgCC* | pgcpp*)
+            # Portland Group C++ compiler
+	    case `$CC -V` in
+	    *pgCC\ [[1-5]].* | *pgcpp\ [[1-5]].*)
+	      _LT_TAGVAR(prelink_cmds, $1)='tpldir=Template.dir~
+               rm -rf $tpldir~
+               $CC --prelink_objects --instantiation_dir $tpldir $objs $libobjs $compile_deplibs~
+               compile_command="$compile_command `find $tpldir -name \*.o | sort | $NL2SP`"'
+	      _LT_TAGVAR(old_archive_cmds, $1)='tpldir=Template.dir~
+                rm -rf $tpldir~
+                $CC --prelink_objects --instantiation_dir $tpldir $oldobjs$old_deplibs~
+                $AR $AR_FLAGS $oldlib$oldobjs$old_deplibs `find $tpldir -name \*.o | sort | $NL2SP`~
+                $RANLIB $oldlib'
+	      _LT_TAGVAR(archive_cmds, $1)='tpldir=Template.dir~
+                rm -rf $tpldir~
+                $CC --prelink_objects --instantiation_dir $tpldir $predep_objects $libobjs $deplibs $convenience $postdep_objects~
+                $CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | sort | $NL2SP` $postdep_objects $compiler_flags $wl-soname $wl$soname -o $lib'
+	      _LT_TAGVAR(archive_expsym_cmds, $1)='tpldir=Template.dir~
+                rm -rf $tpldir~
+                $CC --prelink_objects --instantiation_dir $tpldir $predep_objects $libobjs $deplibs $convenience $postdep_objects~
+                $CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | sort | $NL2SP` $postdep_objects $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+	      ;;
+	    *) # Version 6 and above use weak symbols
+	      _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname -o $lib'
+	      _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $pic_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+	      ;;
+	    esac
+
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl--rpath $wl$libdir'
+	    _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl--export-dynamic'
+	    _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+            ;;
+	  cxx*)
+	    # Compaq C++
+	    _LT_TAGVAR(archive_cmds, $1)='$CC -shared $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname -o $lib'
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname  -o $lib $wl-retain-symbols-file $wl$export_symbols'
+
+	    runpath_var=LD_RUN_PATH
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-rpath $libdir'
+	    _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+
+	    # Commands to make compiler produce verbose output that lists
+	    # what "hidden" libraries, object files and flags are used when
+	    # linking a shared library.
+	    #
+	    # There doesn't appear to be a way to prevent this compiler from
+	    # explicitly linking system object files so we need to strip them
+	    # from the output so that they don't get included in the library
+	    # dependencies.
+	    output_verbose_link_cmd='templist=`$CC -shared $CFLAGS -v conftest.$objext 2>&1 | $GREP "ld"`; templist=`func_echo_all "$templist" | $SED "s/\(^.*ld.*\)\( .*ld .*$\)/\1/"`; list= ; for z in $templist; do case $z in conftest.$objext) list="$list $z";; *.$objext);; *) list="$list $z";;esac; done; func_echo_all "X$list" | $Xsed'
+	    ;;
+	  xl* | mpixl* | bgxl*)
+	    # IBM XL 8.0 on PPC, with GNU ld
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+	    _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl--export-dynamic'
+	    _LT_TAGVAR(archive_cmds, $1)='$CC -qmkshrobj $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	    if test yes = "$supports_anon_versioning"; then
+	      _LT_TAGVAR(archive_expsym_cmds, $1)='echo "{ global:" > $output_objdir/$libname.ver~
+                cat $export_symbols | sed -e "s/\(.*\)/\1;/" >> $output_objdir/$libname.ver~
+                echo "local: *; };" >> $output_objdir/$libname.ver~
+                $CC -qmkshrobj $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-version-script $wl$output_objdir/$libname.ver -o $lib'
+	    fi
+	    ;;
+	  *)
+	    case `$CC -V 2>&1 | sed 5q` in
+	    *Sun\ C*)
+	      # Sun C++ 5.9
+	      _LT_TAGVAR(no_undefined_flag, $1)=' -zdefs'
+	      _LT_TAGVAR(archive_cmds, $1)='$CC -G$allow_undefined_flag -h$soname -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags'
+	      _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -G$allow_undefined_flag -h$soname -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-retain-symbols-file $wl$export_symbols'
+	      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-R$libdir'
+	      _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl--whole-archive`new_convenience=; for conv in $convenience\"\"; do test -z \"$conv\" || new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	      _LT_TAGVAR(compiler_needs_object, $1)=yes
+
+	      # Not sure whether something based on
+	      # $CC $CFLAGS -v conftest.$objext -o libconftest$shared_ext 2>&1
+	      # would be better.
+	      output_verbose_link_cmd='func_echo_all'
+
+	      # Archives containing C++ object files must be created using
+	      # "CC -xar", where "CC" is the Sun C++ compiler.  This is
+	      # necessary to make sure instantiated templates are included
+	      # in the archive.
+	      _LT_TAGVAR(old_archive_cmds, $1)='$CC -xar -o $oldlib $oldobjs'
+	      ;;
+	    esac
+	    ;;
+	esac
+	;;
+
+      lynxos*)
+        # FIXME: insert proper C++ library support
+	_LT_TAGVAR(ld_shlibs, $1)=no
+	;;
+
+      m88k*)
+        # FIXME: insert proper C++ library support
+        _LT_TAGVAR(ld_shlibs, $1)=no
+	;;
+
+      mvs*)
+        case $cc_basename in
+          cxx*)
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+	  *)
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+	esac
+	;;
+
+      netbsd*)
+        if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+	  _LT_TAGVAR(archive_cmds, $1)='$LD -Bshareable  -o $lib $predep_objects $libobjs $deplibs $postdep_objects $linker_flags'
+	  wlarc=
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-R$libdir'
+	  _LT_TAGVAR(hardcode_direct, $1)=yes
+	  _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+	fi
+	# Workaround some broken pre-1.5 toolchains
+	output_verbose_link_cmd='$CC -shared $CFLAGS -v conftest.$objext 2>&1 | $GREP conftest.$objext | $SED -e "s:-lgcc -lc -lgcc::"'
+	;;
+
+      *nto* | *qnx*)
+        _LT_TAGVAR(ld_shlibs, $1)=yes
+	;;
+
+      openbsd* | bitrig*)
+	if test -f /usr/libexec/ld.so; then
+	  _LT_TAGVAR(hardcode_direct, $1)=yes
+	  _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+	  _LT_TAGVAR(hardcode_direct_absolute, $1)=yes
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags -o $lib'
+	  _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath,$libdir'
+	  if test -z "`echo __ELF__ | $CC -E - | grep __ELF__`"; then
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $pic_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-retain-symbols-file,$export_symbols -o $lib'
+	    _LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-E'
+	    _LT_TAGVAR(whole_archive_flag_spec, $1)=$wlarc'--whole-archive$convenience '$wlarc'--no-whole-archive'
+	  fi
+	  output_verbose_link_cmd=func_echo_all
+	else
+	  _LT_TAGVAR(ld_shlibs, $1)=no
+	fi
+	;;
+
+      osf3* | osf4* | osf5*)
+        case $cc_basename in
+          KCC*)
+	    # Kuck and Associates, Inc. (KAI) C++ Compiler
+
+	    # KCC will only create a shared library if the output file
+	    # ends with ".so" (or ".sl" for HP-UX), so rename the library
+	    # to its proper name (with version) after linking.
+	    _LT_TAGVAR(archive_cmds, $1)='tempext=`echo $shared_ext | $SED -e '\''s/\([[^()0-9A-Za-z{}]]\)/\\\\\1/g'\''`; templib=`echo "$lib" | $SED -e "s/\$tempext\..*/.so/"`; $CC $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags --soname $soname -o \$templib; mv \$templib $lib'
+
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath,$libdir'
+	    _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+
+	    # Archives containing C++ object files must be created using
+	    # the KAI C++ compiler.
+	    case $host in
+	      osf3*) _LT_TAGVAR(old_archive_cmds, $1)='$CC -Bstatic -o $oldlib $oldobjs' ;;
+	      *) _LT_TAGVAR(old_archive_cmds, $1)='$CC -o $oldlib $oldobjs' ;;
+	    esac
+	    ;;
+          RCC*)
+	    # Rational C++ 2.4.1
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+          cxx*)
+	    case $host in
+	      osf3*)
+	        _LT_TAGVAR(allow_undefined_flag, $1)=' $wl-expect_unresolved $wl\*'
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -shared$allow_undefined_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $soname `test -n "$verstring" && func_echo_all "$wl-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+	        _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+		;;
+	      *)
+	        _LT_TAGVAR(allow_undefined_flag, $1)=' -expect_unresolved \*'
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -shared$allow_undefined_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags -msym -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+	        _LT_TAGVAR(archive_expsym_cmds, $1)='for i in `cat $export_symbols`; do printf "%s %s\\n" -exported_symbol "\$i" >> $lib.exp; done~
+                  echo "-hidden">> $lib.exp~
+                  $CC -shared$allow_undefined_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags -msym -soname $soname $wl-input $wl$lib.exp  `test -n "$verstring" && $ECHO "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib~
+                  $RM $lib.exp'
+	        _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-rpath $libdir'
+		;;
+	    esac
+
+	    _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+
+	    # Commands to make compiler produce verbose output that lists
+	    # what "hidden" libraries, object files and flags are used when
+	    # linking a shared library.
+	    #
+	    # There doesn't appear to be a way to prevent this compiler from
+	    # explicitly linking system object files so we need to strip them
+	    # from the output so that they don't get included in the library
+	    # dependencies.
+	    output_verbose_link_cmd='templist=`$CC -shared $CFLAGS -v conftest.$objext 2>&1 | $GREP "ld" | $GREP -v "ld:"`; templist=`func_echo_all "$templist" | $SED "s/\(^.*ld.*\)\( .*ld.*$\)/\1/"`; list= ; for z in $templist; do case $z in conftest.$objext) list="$list $z";; *.$objext);; *) list="$list $z";;esac; done; func_echo_all "$list"'
+	    ;;
+	  *)
+	    if test yes,no = "$GXX,$with_gnu_ld"; then
+	      _LT_TAGVAR(allow_undefined_flag, $1)=' $wl-expect_unresolved $wl\*'
+	      case $host in
+	        osf3*)
+	          _LT_TAGVAR(archive_cmds, $1)='$CC -shared -nostdlib $allow_undefined_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+		  ;;
+	        *)
+	          _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag -nostdlib $allow_undefined_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-msym $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+		  ;;
+	      esac
+
+	      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
+	      _LT_TAGVAR(hardcode_libdir_separator, $1)=:
+
+	      # Commands to make compiler produce verbose output that lists
+	      # what "hidden" libraries, object files and flags are used when
+	      # linking a shared library.
+	      output_verbose_link_cmd='$CC -shared $CFLAGS -v conftest.$objext 2>&1 | $GREP -v "^Configured with:" | $GREP "\-L"'
+
+	    else
+	      # FIXME: insert proper C++ library support
+	      _LT_TAGVAR(ld_shlibs, $1)=no
+	    fi
+	    ;;
+        esac
+        ;;
+
+      psos*)
+        # FIXME: insert proper C++ library support
+        _LT_TAGVAR(ld_shlibs, $1)=no
+        ;;
+
+      sunos4*)
+        case $cc_basename in
+          CC*)
+	    # Sun C++ 4.x
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+          lcc*)
+	    # Lucid
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+          *)
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+        esac
+        ;;
+
+      solaris*)
+        case $cc_basename in
+          CC* | sunCC*)
+	    # Sun C++ 4.2, 5.x and Centerline C++
+            _LT_TAGVAR(archive_cmds_need_lc,$1)=yes
+	    _LT_TAGVAR(no_undefined_flag, $1)=' -zdefs'
+	    _LT_TAGVAR(archive_cmds, $1)='$CC -G$allow_undefined_flag -h$soname -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags'
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+              $CC -G$allow_undefined_flag $wl-M $wl$lib.exp -h$soname -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags~$RM $lib.exp'
+
+	    _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-R$libdir'
+	    _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+	    case $host_os in
+	      solaris2.[[0-5]] | solaris2.[[0-5]].*) ;;
+	      *)
+		# The compiler driver will combine and reorder linker options,
+		# but understands '-z linker_flag'.
+	        # Supported since Solaris 2.6 (maybe 2.5.1?)
+		_LT_TAGVAR(whole_archive_flag_spec, $1)='-z allextract$convenience -z defaultextract'
+	        ;;
+	    esac
+	    _LT_TAGVAR(link_all_deplibs, $1)=yes
+
+	    output_verbose_link_cmd='func_echo_all'
+
+	    # Archives containing C++ object files must be created using
+	    # "CC -xar", where "CC" is the Sun C++ compiler.  This is
+	    # necessary to make sure instantiated templates are included
+	    # in the archive.
+	    _LT_TAGVAR(old_archive_cmds, $1)='$CC -xar -o $oldlib $oldobjs'
+	    ;;
+          gcx*)
+	    # Green Hills C++ Compiler
+	    _LT_TAGVAR(archive_cmds, $1)='$CC -shared $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-h $wl$soname -o $lib'
+
+	    # The C++ compiler must be used to create the archive.
+	    _LT_TAGVAR(old_archive_cmds, $1)='$CC $LDFLAGS -archive -o $oldlib $oldobjs'
+	    ;;
+          *)
+	    # GNU C++ compiler with Solaris linker
+	    if test yes,no = "$GXX,$with_gnu_ld"; then
+	      _LT_TAGVAR(no_undefined_flag, $1)=' $wl-z ${wl}defs'
+	      if $CC --version | $GREP -v '^2\.7' > /dev/null; then
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-h $wl$soname -o $lib'
+	        _LT_TAGVAR(archive_expsym_cmds, $1)='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+                  $CC -shared $pic_flag -nostdlib $wl-M $wl$lib.exp $wl-h $wl$soname -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags~$RM $lib.exp'
+
+	        # Commands to make compiler produce verbose output that lists
+	        # what "hidden" libraries, object files and flags are used when
+	        # linking a shared library.
+	        output_verbose_link_cmd='$CC -shared $CFLAGS -v conftest.$objext 2>&1 | $GREP -v "^Configured with:" | $GREP "\-L"'
+	      else
+	        # g++ 2.7 appears to require '-G' NOT '-shared' on this
+	        # platform.
+	        _LT_TAGVAR(archive_cmds, $1)='$CC -G -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-h $wl$soname -o $lib'
+	        _LT_TAGVAR(archive_expsym_cmds, $1)='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+                  $CC -G -nostdlib $wl-M $wl$lib.exp $wl-h $wl$soname -o $lib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags~$RM $lib.exp'
+
+	        # Commands to make compiler produce verbose output that lists
+	        # what "hidden" libraries, object files and flags are used when
+	        # linking a shared library.
+	        output_verbose_link_cmd='$CC -G $CFLAGS -v conftest.$objext 2>&1 | $GREP -v "^Configured with:" | $GREP "\-L"'
+	      fi
+
+	      _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-R $wl$libdir'
+	      case $host_os in
+		solaris2.[[0-5]] | solaris2.[[0-5]].*) ;;
+		*)
+		  _LT_TAGVAR(whole_archive_flag_spec, $1)='$wl-z ${wl}allextract$convenience $wl-z ${wl}defaultextract'
+		  ;;
+	      esac
+	    fi
+	    ;;
+        esac
+        ;;
+
+    sysv4*uw2* | sysv5OpenUNIX* | sysv5UnixWare7.[[01]].[[10]]* | unixware7* | sco3.2v5.0.[[024]]*)
+      _LT_TAGVAR(no_undefined_flag, $1)='$wl-z,text'
+      _LT_TAGVAR(archive_cmds_need_lc, $1)=no
+      _LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+      runpath_var='LD_RUN_PATH'
+
+      case $cc_basename in
+        CC*)
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -G $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -G $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	*)
+	  _LT_TAGVAR(archive_cmds, $1)='$CC -shared $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+      esac
+      ;;
+
+      sysv5* | sco3.2v5* | sco5v6*)
+	# Note: We CANNOT use -z defs as we might desire, because we do not
+	# link with -lc, and that would cause any symbols used from libc to
+	# always be unresolved, which means just about no library would
+	# ever link correctly.  If we're not using GNU ld we use -z text
+	# though, which does catch some bad symbols but isn't as heavy-handed
+	# as -z defs.
+	_LT_TAGVAR(no_undefined_flag, $1)='$wl-z,text'
+	_LT_TAGVAR(allow_undefined_flag, $1)='$wl-z,nodefs'
+	_LT_TAGVAR(archive_cmds_need_lc, $1)=no
+	_LT_TAGVAR(hardcode_shlibpath_var, $1)=no
+	_LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-R,$libdir'
+	_LT_TAGVAR(hardcode_libdir_separator, $1)=':'
+	_LT_TAGVAR(link_all_deplibs, $1)=yes
+	_LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl-Bexport'
+	runpath_var='LD_RUN_PATH'
+
+	case $cc_basename in
+          CC*)
+	    _LT_TAGVAR(archive_cmds, $1)='$CC -G $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -G $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	    _LT_TAGVAR(old_archive_cmds, $1)='$CC -Tprelink_objects $oldobjs~
+              '"$_LT_TAGVAR(old_archive_cmds, $1)"
+	    _LT_TAGVAR(reload_cmds, $1)='$CC -Tprelink_objects $reload_objs~
+              '"$_LT_TAGVAR(reload_cmds, $1)"
+	    ;;
+	  *)
+	    _LT_TAGVAR(archive_cmds, $1)='$CC -shared $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	    _LT_TAGVAR(archive_expsym_cmds, $1)='$CC -shared $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	    ;;
+	esac
+      ;;
+
+      tandem*)
+        case $cc_basename in
+          NCC*)
+	    # NonStop-UX NCC 3.20
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+          *)
+	    # FIXME: insert proper C++ library support
+	    _LT_TAGVAR(ld_shlibs, $1)=no
+	    ;;
+        esac
+        ;;
+
+      vxworks*)
+        # FIXME: insert proper C++ library support
+        _LT_TAGVAR(ld_shlibs, $1)=no
+        ;;
+
+      *)
+        # FIXME: insert proper C++ library support
+        _LT_TAGVAR(ld_shlibs, $1)=no
+        ;;
+    esac
+
+    AC_MSG_RESULT([$_LT_TAGVAR(ld_shlibs, $1)])
+    test no = "$_LT_TAGVAR(ld_shlibs, $1)" && can_build_shared=no
+
+    _LT_TAGVAR(GCC, $1)=$GXX
+    _LT_TAGVAR(LD, $1)=$LD
+
+    ## CAVEAT EMPTOR:
+    ## There is no encapsulation within the following macros, do not change
+    ## the running order or otherwise move them around unless you know exactly
+    ## what you are doing...
+    _LT_SYS_HIDDEN_LIBDEPS($1)
+    _LT_COMPILER_PIC($1)
+    _LT_COMPILER_C_O($1)
+    _LT_COMPILER_FILE_LOCKS($1)
+    _LT_LINKER_SHLIBS($1)
+    _LT_SYS_DYNAMIC_LINKER($1)
+    _LT_LINKER_HARDCODE_LIBPATH($1)
+
+    _LT_CONFIG($1)
+  fi # test -n "$compiler"
+
+  CC=$lt_save_CC
+  CFLAGS=$lt_save_CFLAGS
+  LDCXX=$LD
+  LD=$lt_save_LD
+  GCC=$lt_save_GCC
+  with_gnu_ld=$lt_save_with_gnu_ld
+  lt_cv_path_LDCXX=$lt_cv_path_LD
+  lt_cv_path_LD=$lt_save_path_LD
+  lt_cv_prog_gnu_ldcxx=$lt_cv_prog_gnu_ld
+  lt_cv_prog_gnu_ld=$lt_save_with_gnu_ld
+fi # test yes != "$_lt_caught_CXX_error"
+
+AC_LANG_POP
+])# _LT_LANG_CXX_CONFIG
+
+
+# _LT_FUNC_STRIPNAME_CNF
+# ----------------------
+# func_stripname_cnf prefix suffix name
+# strip PREFIX and SUFFIX off of NAME.
+# PREFIX and SUFFIX must not contain globbing or regex special
+# characters, hashes, percent signs, but SUFFIX may contain a leading
+# dot (in which case that matches only a dot).
+#
+# This function is identical to the (non-XSI) version of func_stripname,
+# except this one can be used by m4 code that may be executed by configure,
+# rather than the libtool script.
+m4_defun([_LT_FUNC_STRIPNAME_CNF],[dnl
+AC_REQUIRE([_LT_DECL_SED])
+AC_REQUIRE([_LT_PROG_ECHO_BACKSLASH])
+func_stripname_cnf ()
+{
+  case @S|@2 in
+  .*) func_stripname_result=`$ECHO "@S|@3" | $SED "s%^@S|@1%%; s%\\\\@S|@2\$%%"`;;
+  *)  func_stripname_result=`$ECHO "@S|@3" | $SED "s%^@S|@1%%; s%@S|@2\$%%"`;;
+  esac
+} # func_stripname_cnf
+])# _LT_FUNC_STRIPNAME_CNF
+
+
+# _LT_SYS_HIDDEN_LIBDEPS([TAGNAME])
+# ---------------------------------
+# Figure out "hidden" library dependencies from verbose
+# compiler output when linking a shared library.
+# Parse the compiler output and extract the necessary
+# objects, libraries and library flags.
+m4_defun([_LT_SYS_HIDDEN_LIBDEPS],
+[m4_require([_LT_FILEUTILS_DEFAULTS])dnl
+AC_REQUIRE([_LT_FUNC_STRIPNAME_CNF])dnl
+# Dependencies to place before and after the object being linked:
+_LT_TAGVAR(predep_objects, $1)=
+_LT_TAGVAR(postdep_objects, $1)=
+_LT_TAGVAR(predeps, $1)=
+_LT_TAGVAR(postdeps, $1)=
+_LT_TAGVAR(compiler_lib_search_path, $1)=
+
+dnl we can't use the lt_simple_compile_test_code here,
+dnl because it contains code intended for an executable,
+dnl not a library.  It's possible we should let each
+dnl tag define a new lt_????_link_test_code variable,
+dnl but it's only used here...
+m4_if([$1], [], [cat > conftest.$ac_ext <<_LT_EOF
+int a;
+void foo (void) { a = 0; }
+_LT_EOF
+], [$1], [CXX], [cat > conftest.$ac_ext <<_LT_EOF
+class Foo
+{
+public:
+  Foo (void) { a = 0; }
+private:
+  int a;
+};
+_LT_EOF
+], [$1], [F77], [cat > conftest.$ac_ext <<_LT_EOF
+      subroutine foo
+      implicit none
+      integer*4 a
+      a=0
+      return
+      end
+_LT_EOF
+], [$1], [FC], [cat > conftest.$ac_ext <<_LT_EOF
+      subroutine foo
+      implicit none
+      integer a
+      a=0
+      return
+      end
+_LT_EOF
+], [$1], [GCJ], [cat > conftest.$ac_ext <<_LT_EOF
+public class foo {
+  private int a;
+  public void bar (void) {
+    a = 0;
+  }
+};
+_LT_EOF
+], [$1], [GO], [cat > conftest.$ac_ext <<_LT_EOF
+package foo
+func foo() {
+}
+_LT_EOF
+])
+
+_lt_libdeps_save_CFLAGS=$CFLAGS
+case "$CC $CFLAGS " in #(
+*\ -flto*\ *) CFLAGS="$CFLAGS -fno-lto" ;;
+*\ -fwhopr*\ *) CFLAGS="$CFLAGS -fno-whopr" ;;
+*\ -fuse-linker-plugin*\ *) CFLAGS="$CFLAGS -fno-use-linker-plugin" ;;
+esac
+
+dnl Parse the compiler output and extract the necessary
+dnl objects, libraries and library flags.
+if AC_TRY_EVAL(ac_compile); then
+  # Parse the compiler output and extract the necessary
+  # objects, libraries and library flags.
+
+  # Sentinel used to keep track of whether or not we are before
+  # the conftest object file.
+  pre_test_object_deps_done=no
+
+  for p in `eval "$output_verbose_link_cmd"`; do
+    case $prev$p in
+
+    -L* | -R* | -l*)
+       # Some compilers place space between "-{L,R}" and the path.
+       # Remove the space.
+       if test x-L = "$p" ||
+          test x-R = "$p"; then
+	 prev=$p
+	 continue
+       fi
+
+       # Expand the sysroot to ease extracting the directories later.
+       if test -z "$prev"; then
+         case $p in
+         -L*) func_stripname_cnf '-L' '' "$p"; prev=-L; p=$func_stripname_result ;;
+         -R*) func_stripname_cnf '-R' '' "$p"; prev=-R; p=$func_stripname_result ;;
+         -l*) func_stripname_cnf '-l' '' "$p"; prev=-l; p=$func_stripname_result ;;
+         esac
+       fi
+       case $p in
+       =*) func_stripname_cnf '=' '' "$p"; p=$lt_sysroot$func_stripname_result ;;
+       esac
+       if test no = "$pre_test_object_deps_done"; then
+	 case $prev in
+	 -L | -R)
+	   # Internal compiler library paths should come after those
+	   # provided the user.  The postdeps already come after the
+	   # user supplied libs so there is no need to process them.
+	   if test -z "$_LT_TAGVAR(compiler_lib_search_path, $1)"; then
+	     _LT_TAGVAR(compiler_lib_search_path, $1)=$prev$p
+	   else
+	     _LT_TAGVAR(compiler_lib_search_path, $1)="${_LT_TAGVAR(compiler_lib_search_path, $1)} $prev$p"
+	   fi
+	   ;;
+	 # The "-l" case would never come before the object being
+	 # linked, so don't bother handling this case.
+	 esac
+       else
+	 if test -z "$_LT_TAGVAR(postdeps, $1)"; then
+	   _LT_TAGVAR(postdeps, $1)=$prev$p
+	 else
+	   _LT_TAGVAR(postdeps, $1)="${_LT_TAGVAR(postdeps, $1)} $prev$p"
+	 fi
+       fi
+       prev=
+       ;;
+
+    *.lto.$objext) ;; # Ignore GCC LTO objects
+    *.$objext)
+       # This assumes that the test object file only shows up
+       # once in the compiler output.
+       if test "$p" = "conftest.$objext"; then
+	 pre_test_object_deps_done=yes
+	 continue
+       fi
+
+       if test no = "$pre_test_object_deps_done"; then
+	 if test -z "$_LT_TAGVAR(predep_objects, $1)"; then
+	   _LT_TAGVAR(predep_objects, $1)=$p
+	 else
+	   _LT_TAGVAR(predep_objects, $1)="$_LT_TAGVAR(predep_objects, $1) $p"
+	 fi
+       else
+	 if test -z "$_LT_TAGVAR(postdep_objects, $1)"; then
+	   _LT_TAGVAR(postdep_objects, $1)=$p
+	 else
+	   _LT_TAGVAR(postdep_objects, $1)="$_LT_TAGVAR(postdep_objects, $1) $p"
+	 fi
+       fi
+       ;;
+
+    *) ;; # Ignore the rest.
+
+    esac
+  done
+
+  # Clean up.
+  rm -f a.out a.exe
+else
+  echo "libtool.m4: error: problem compiling $1 test program"
+fi
+
+$RM -f confest.$objext
+CFLAGS=$_lt_libdeps_save_CFLAGS
+
+# PORTME: override above test on systems where it is broken
+m4_if([$1], [CXX],
+[case $host_os in
+interix[[3-9]]*)
+  # Interix 3.5 installs completely hosed .la files for C++, so rather than
+  # hack all around it, let's just trust "g++" to DTRT.
+  _LT_TAGVAR(predep_objects,$1)=
+  _LT_TAGVAR(postdep_objects,$1)=
+  _LT_TAGVAR(postdeps,$1)=
+  ;;
+esac
+])
+
+case " $_LT_TAGVAR(postdeps, $1) " in
+*" -lc "*) _LT_TAGVAR(archive_cmds_need_lc, $1)=no ;;
+esac
+ _LT_TAGVAR(compiler_lib_search_dirs, $1)=
+if test -n "${_LT_TAGVAR(compiler_lib_search_path, $1)}"; then
+ _LT_TAGVAR(compiler_lib_search_dirs, $1)=`echo " ${_LT_TAGVAR(compiler_lib_search_path, $1)}" | $SED -e 's! -L! !g' -e 's!^ !!'`
+fi
+_LT_TAGDECL([], [compiler_lib_search_dirs], [1],
+    [The directories searched by this compiler when creating a shared library])
+_LT_TAGDECL([], [predep_objects], [1],
+    [Dependencies to place before and after the objects being linked to
+    create a shared library])
+_LT_TAGDECL([], [postdep_objects], [1])
+_LT_TAGDECL([], [predeps], [1])
+_LT_TAGDECL([], [postdeps], [1])
+_LT_TAGDECL([], [compiler_lib_search_path], [1],
+    [The library search path used internally by the compiler when linking
+    a shared library])
+])# _LT_SYS_HIDDEN_LIBDEPS
+
+
+# _LT_LANG_F77_CONFIG([TAG])
+# --------------------------
+# Ensure that the configuration variables for a Fortran 77 compiler are
+# suitably defined.  These variables are subsequently used by _LT_CONFIG
+# to write the compiler configuration to 'libtool'.
+m4_defun([_LT_LANG_F77_CONFIG],
+[AC_LANG_PUSH(Fortran 77)
+if test -z "$F77" || test no = "$F77"; then
+  _lt_disable_F77=yes
+fi
+
+_LT_TAGVAR(archive_cmds_need_lc, $1)=no
+_LT_TAGVAR(allow_undefined_flag, $1)=
+_LT_TAGVAR(always_export_symbols, $1)=no
+_LT_TAGVAR(archive_expsym_cmds, $1)=
+_LT_TAGVAR(export_dynamic_flag_spec, $1)=
+_LT_TAGVAR(hardcode_direct, $1)=no
+_LT_TAGVAR(hardcode_direct_absolute, $1)=no
+_LT_TAGVAR(hardcode_libdir_flag_spec, $1)=
+_LT_TAGVAR(hardcode_libdir_separator, $1)=
+_LT_TAGVAR(hardcode_minus_L, $1)=no
+_LT_TAGVAR(hardcode_automatic, $1)=no
+_LT_TAGVAR(inherit_rpath, $1)=no
+_LT_TAGVAR(module_cmds, $1)=
+_LT_TAGVAR(module_expsym_cmds, $1)=
+_LT_TAGVAR(link_all_deplibs, $1)=unknown
+_LT_TAGVAR(old_archive_cmds, $1)=$old_archive_cmds
+_LT_TAGVAR(reload_flag, $1)=$reload_flag
+_LT_TAGVAR(reload_cmds, $1)=$reload_cmds
+_LT_TAGVAR(no_undefined_flag, $1)=
+_LT_TAGVAR(whole_archive_flag_spec, $1)=
+_LT_TAGVAR(enable_shared_with_static_runtimes, $1)=no
+
+# Source file extension for f77 test sources.
+ac_ext=f
+
+# Object file extension for compiled f77 test sources.
+objext=o
+_LT_TAGVAR(objext, $1)=$objext
+
+# No sense in running all these tests if we already determined that
+# the F77 compiler isn't working.  Some variables (like enable_shared)
+# are currently assumed to apply to all compilers on this platform,
+# and will be corrupted by setting them based on a non-working compiler.
+if test yes != "$_lt_disable_F77"; then
+  # Code to be used in simple compile tests
+  lt_simple_compile_test_code="\
+      subroutine t
+      return
+      end
+"
+
+  # Code to be used in simple link tests
+  lt_simple_link_test_code="\
+      program t
+      end
+"
+
+  # ltmain only uses $CC for tagged configurations so make sure $CC is set.
+  _LT_TAG_COMPILER
+
+  # save warnings/boilerplate of simple test code
+  _LT_COMPILER_BOILERPLATE
+  _LT_LINKER_BOILERPLATE
+
+  # Allow CC to be a program name with arguments.
+  lt_save_CC=$CC
+  lt_save_GCC=$GCC
+  lt_save_CFLAGS=$CFLAGS
+  CC=${F77-"f77"}
+  CFLAGS=$FFLAGS
+  compiler=$CC
+  _LT_TAGVAR(compiler, $1)=$CC
+  _LT_CC_BASENAME([$compiler])
+  GCC=$G77
+  if test -n "$compiler"; then
+    AC_MSG_CHECKING([if libtool supports shared libraries])
+    AC_MSG_RESULT([$can_build_shared])
+
+    AC_MSG_CHECKING([whether to build shared libraries])
+    test no = "$can_build_shared" && enable_shared=no
+
+    # On AIX, shared libraries and static libraries use the same namespace, and
+    # are all built from PIC.
+    case $host_os in
+      aix3*)
+        test yes = "$enable_shared" && enable_static=no
+        if test -n "$RANLIB"; then
+          archive_cmds="$archive_cmds~\$RANLIB \$lib"
+          postinstall_cmds='$RANLIB $lib'
+        fi
+        ;;
+      aix[[4-9]]*)
+	if test ia64 != "$host_cpu"; then
+	  case $enable_shared,$with_aix_soname,$aix_use_runtimelinking in
+	  yes,aix,yes) ;;		# shared object as lib.so file only
+	  yes,svr4,*) ;;		# shared object as lib.so archive member only
+	  yes,*) enable_static=no ;;	# shared object in lib.a archive as well
+	  esac
+	fi
+        ;;
+    esac
+    AC_MSG_RESULT([$enable_shared])
+
+    AC_MSG_CHECKING([whether to build static libraries])
+    # Make sure either enable_shared or enable_static is yes.
+    test yes = "$enable_shared" || enable_static=yes
+    AC_MSG_RESULT([$enable_static])
+
+    _LT_TAGVAR(GCC, $1)=$G77
+    _LT_TAGVAR(LD, $1)=$LD
+
+    ## CAVEAT EMPTOR:
+    ## There is no encapsulation within the following macros, do not change
+    ## the running order or otherwise move them around unless you know exactly
+    ## what you are doing...
+    _LT_COMPILER_PIC($1)
+    _LT_COMPILER_C_O($1)
+    _LT_COMPILER_FILE_LOCKS($1)
+    _LT_LINKER_SHLIBS($1)
+    _LT_SYS_DYNAMIC_LINKER($1)
+    _LT_LINKER_HARDCODE_LIBPATH($1)
+
+    _LT_CONFIG($1)
+  fi # test -n "$compiler"
+
+  GCC=$lt_save_GCC
+  CC=$lt_save_CC
+  CFLAGS=$lt_save_CFLAGS
+fi # test yes != "$_lt_disable_F77"
+
+AC_LANG_POP
+])# _LT_LANG_F77_CONFIG
+
+
+# _LT_LANG_FC_CONFIG([TAG])
+# -------------------------
+# Ensure that the configuration variables for a Fortran compiler are
+# suitably defined.  These variables are subsequently used by _LT_CONFIG
+# to write the compiler configuration to 'libtool'.
+m4_defun([_LT_LANG_FC_CONFIG],
+[AC_LANG_PUSH(Fortran)
+
+if test -z "$FC" || test no = "$FC"; then
+  _lt_disable_FC=yes
+fi
+
+_LT_TAGVAR(archive_cmds_need_lc, $1)=no
+_LT_TAGVAR(allow_undefined_flag, $1)=
+_LT_TAGVAR(always_export_symbols, $1)=no
+_LT_TAGVAR(archive_expsym_cmds, $1)=
+_LT_TAGVAR(export_dynamic_flag_spec, $1)=
+_LT_TAGVAR(hardcode_direct, $1)=no
+_LT_TAGVAR(hardcode_direct_absolute, $1)=no
+_LT_TAGVAR(hardcode_libdir_flag_spec, $1)=
+_LT_TAGVAR(hardcode_libdir_separator, $1)=
+_LT_TAGVAR(hardcode_minus_L, $1)=no
+_LT_TAGVAR(hardcode_automatic, $1)=no
+_LT_TAGVAR(inherit_rpath, $1)=no
+_LT_TAGVAR(module_cmds, $1)=
+_LT_TAGVAR(module_expsym_cmds, $1)=
+_LT_TAGVAR(link_all_deplibs, $1)=unknown
+_LT_TAGVAR(old_archive_cmds, $1)=$old_archive_cmds
+_LT_TAGVAR(reload_flag, $1)=$reload_flag
+_LT_TAGVAR(reload_cmds, $1)=$reload_cmds
+_LT_TAGVAR(no_undefined_flag, $1)=
+_LT_TAGVAR(whole_archive_flag_spec, $1)=
+_LT_TAGVAR(enable_shared_with_static_runtimes, $1)=no
+
+# Source file extension for fc test sources.
+ac_ext=${ac_fc_srcext-f}
+
+# Object file extension for compiled fc test sources.
+objext=o
+_LT_TAGVAR(objext, $1)=$objext
+
+# No sense in running all these tests if we already determined that
+# the FC compiler isn't working.  Some variables (like enable_shared)
+# are currently assumed to apply to all compilers on this platform,
+# and will be corrupted by setting them based on a non-working compiler.
+if test yes != "$_lt_disable_FC"; then
+  # Code to be used in simple compile tests
+  lt_simple_compile_test_code="\
+      subroutine t
+      return
+      end
+"
+
+  # Code to be used in simple link tests
+  lt_simple_link_test_code="\
+      program t
+      end
+"
+
+  # ltmain only uses $CC for tagged configurations so make sure $CC is set.
+  _LT_TAG_COMPILER
+
+  # save warnings/boilerplate of simple test code
+  _LT_COMPILER_BOILERPLATE
+  _LT_LINKER_BOILERPLATE
+
+  # Allow CC to be a program name with arguments.
+  lt_save_CC=$CC
+  lt_save_GCC=$GCC
+  lt_save_CFLAGS=$CFLAGS
+  CC=${FC-"f95"}
+  CFLAGS=$FCFLAGS
+  compiler=$CC
+  GCC=$ac_cv_fc_compiler_gnu
+
+  _LT_TAGVAR(compiler, $1)=$CC
+  _LT_CC_BASENAME([$compiler])
+
+  if test -n "$compiler"; then
+    AC_MSG_CHECKING([if libtool supports shared libraries])
+    AC_MSG_RESULT([$can_build_shared])
+
+    AC_MSG_CHECKING([whether to build shared libraries])
+    test no = "$can_build_shared" && enable_shared=no
+
+    # On AIX, shared libraries and static libraries use the same namespace, and
+    # are all built from PIC.
+    case $host_os in
+      aix3*)
+        test yes = "$enable_shared" && enable_static=no
+        if test -n "$RANLIB"; then
+          archive_cmds="$archive_cmds~\$RANLIB \$lib"
+          postinstall_cmds='$RANLIB $lib'
+        fi
+        ;;
+      aix[[4-9]]*)
+	if test ia64 != "$host_cpu"; then
+	  case $enable_shared,$with_aix_soname,$aix_use_runtimelinking in
+	  yes,aix,yes) ;;		# shared object as lib.so file only
+	  yes,svr4,*) ;;		# shared object as lib.so archive member only
+	  yes,*) enable_static=no ;;	# shared object in lib.a archive as well
+	  esac
+	fi
+        ;;
+    esac
+    AC_MSG_RESULT([$enable_shared])
+
+    AC_MSG_CHECKING([whether to build static libraries])
+    # Make sure either enable_shared or enable_static is yes.
+    test yes = "$enable_shared" || enable_static=yes
+    AC_MSG_RESULT([$enable_static])
+
+    _LT_TAGVAR(GCC, $1)=$ac_cv_fc_compiler_gnu
+    _LT_TAGVAR(LD, $1)=$LD
+
+    ## CAVEAT EMPTOR:
+    ## There is no encapsulation within the following macros, do not change
+    ## the running order or otherwise move them around unless you know exactly
+    ## what you are doing...
+    _LT_SYS_HIDDEN_LIBDEPS($1)
+    _LT_COMPILER_PIC($1)
+    _LT_COMPILER_C_O($1)
+    _LT_COMPILER_FILE_LOCKS($1)
+    _LT_LINKER_SHLIBS($1)
+    _LT_SYS_DYNAMIC_LINKER($1)
+    _LT_LINKER_HARDCODE_LIBPATH($1)
+
+    _LT_CONFIG($1)
+  fi # test -n "$compiler"
+
+  GCC=$lt_save_GCC
+  CC=$lt_save_CC
+  CFLAGS=$lt_save_CFLAGS
+fi # test yes != "$_lt_disable_FC"
+
+AC_LANG_POP
+])# _LT_LANG_FC_CONFIG
+
+
+# _LT_LANG_GCJ_CONFIG([TAG])
+# --------------------------
+# Ensure that the configuration variables for the GNU Java Compiler compiler
+# are suitably defined.  These variables are subsequently used by _LT_CONFIG
+# to write the compiler configuration to 'libtool'.
+m4_defun([_LT_LANG_GCJ_CONFIG],
+[AC_REQUIRE([LT_PROG_GCJ])dnl
+AC_LANG_SAVE
+
+# Source file extension for Java test sources.
+ac_ext=java
+
+# Object file extension for compiled Java test sources.
+objext=o
+_LT_TAGVAR(objext, $1)=$objext
+
+# Code to be used in simple compile tests
+lt_simple_compile_test_code="class foo {}"
+
+# Code to be used in simple link tests
+lt_simple_link_test_code='public class conftest { public static void main(String[[]] argv) {}; }'
+
+# ltmain only uses $CC for tagged configurations so make sure $CC is set.
+_LT_TAG_COMPILER
+
+# save warnings/boilerplate of simple test code
+_LT_COMPILER_BOILERPLATE
+_LT_LINKER_BOILERPLATE
+
+# Allow CC to be a program name with arguments.
+lt_save_CC=$CC
+lt_save_CFLAGS=$CFLAGS
+lt_save_GCC=$GCC
+GCC=yes
+CC=${GCJ-"gcj"}
+CFLAGS=$GCJFLAGS
+compiler=$CC
+_LT_TAGVAR(compiler, $1)=$CC
+_LT_TAGVAR(LD, $1)=$LD
+_LT_CC_BASENAME([$compiler])
+
+# GCJ did not exist at the time GCC didn't implicitly link libc in.
+_LT_TAGVAR(archive_cmds_need_lc, $1)=no
+
+_LT_TAGVAR(old_archive_cmds, $1)=$old_archive_cmds
+_LT_TAGVAR(reload_flag, $1)=$reload_flag
+_LT_TAGVAR(reload_cmds, $1)=$reload_cmds
+
+## CAVEAT EMPTOR:
+## There is no encapsulation within the following macros, do not change
+## the running order or otherwise move them around unless you know exactly
+## what you are doing...
+if test -n "$compiler"; then
+  _LT_COMPILER_NO_RTTI($1)
+  _LT_COMPILER_PIC($1)
+  _LT_COMPILER_C_O($1)
+  _LT_COMPILER_FILE_LOCKS($1)
+  _LT_LINKER_SHLIBS($1)
+  _LT_LINKER_HARDCODE_LIBPATH($1)
+
+  _LT_CONFIG($1)
+fi
+
+AC_LANG_RESTORE
+
+GCC=$lt_save_GCC
+CC=$lt_save_CC
+CFLAGS=$lt_save_CFLAGS
+])# _LT_LANG_GCJ_CONFIG
+
+
+# _LT_LANG_GO_CONFIG([TAG])
+# --------------------------
+# Ensure that the configuration variables for the GNU Go compiler
+# are suitably defined.  These variables are subsequently used by _LT_CONFIG
+# to write the compiler configuration to 'libtool'.
+m4_defun([_LT_LANG_GO_CONFIG],
+[AC_REQUIRE([LT_PROG_GO])dnl
+AC_LANG_SAVE
+
+# Source file extension for Go test sources.
+ac_ext=go
+
+# Object file extension for compiled Go test sources.
+objext=o
+_LT_TAGVAR(objext, $1)=$objext
+
+# Code to be used in simple compile tests
+lt_simple_compile_test_code="package main; func main() { }"
+
+# Code to be used in simple link tests
+lt_simple_link_test_code='package main; func main() { }'
+
+# ltmain only uses $CC for tagged configurations so make sure $CC is set.
+_LT_TAG_COMPILER
+
+# save warnings/boilerplate of simple test code
+_LT_COMPILER_BOILERPLATE
+_LT_LINKER_BOILERPLATE
+
+# Allow CC to be a program name with arguments.
+lt_save_CC=$CC
+lt_save_CFLAGS=$CFLAGS
+lt_save_GCC=$GCC
+GCC=yes
+CC=${GOC-"gccgo"}
+CFLAGS=$GOFLAGS
+compiler=$CC
+_LT_TAGVAR(compiler, $1)=$CC
+_LT_TAGVAR(LD, $1)=$LD
+_LT_CC_BASENAME([$compiler])
+
+# Go did not exist at the time GCC didn't implicitly link libc in.
+_LT_TAGVAR(archive_cmds_need_lc, $1)=no
+
+_LT_TAGVAR(old_archive_cmds, $1)=$old_archive_cmds
+_LT_TAGVAR(reload_flag, $1)=$reload_flag
+_LT_TAGVAR(reload_cmds, $1)=$reload_cmds
+
+## CAVEAT EMPTOR:
+## There is no encapsulation within the following macros, do not change
+## the running order or otherwise move them around unless you know exactly
+## what you are doing...
+if test -n "$compiler"; then
+  _LT_COMPILER_NO_RTTI($1)
+  _LT_COMPILER_PIC($1)
+  _LT_COMPILER_C_O($1)
+  _LT_COMPILER_FILE_LOCKS($1)
+  _LT_LINKER_SHLIBS($1)
+  _LT_LINKER_HARDCODE_LIBPATH($1)
+
+  _LT_CONFIG($1)
+fi
+
+AC_LANG_RESTORE
+
+GCC=$lt_save_GCC
+CC=$lt_save_CC
+CFLAGS=$lt_save_CFLAGS
+])# _LT_LANG_GO_CONFIG
+
+
+# _LT_LANG_RC_CONFIG([TAG])
+# -------------------------
+# Ensure that the configuration variables for the Windows resource compiler
+# are suitably defined.  These variables are subsequently used by _LT_CONFIG
+# to write the compiler configuration to 'libtool'.
+m4_defun([_LT_LANG_RC_CONFIG],
+[AC_REQUIRE([LT_PROG_RC])dnl
+AC_LANG_SAVE
+
+# Source file extension for RC test sources.
+ac_ext=rc
+
+# Object file extension for compiled RC test sources.
+objext=o
+_LT_TAGVAR(objext, $1)=$objext
+
+# Code to be used in simple compile tests
+lt_simple_compile_test_code='sample MENU { MENUITEM "&Soup", 100, CHECKED }'
+
+# Code to be used in simple link tests
+lt_simple_link_test_code=$lt_simple_compile_test_code
+
+# ltmain only uses $CC for tagged configurations so make sure $CC is set.
+_LT_TAG_COMPILER
+
+# save warnings/boilerplate of simple test code
+_LT_COMPILER_BOILERPLATE
+_LT_LINKER_BOILERPLATE
+
+# Allow CC to be a program name with arguments.
+lt_save_CC=$CC
+lt_save_CFLAGS=$CFLAGS
+lt_save_GCC=$GCC
+GCC=
+CC=${RC-"windres"}
+CFLAGS=
+compiler=$CC
+_LT_TAGVAR(compiler, $1)=$CC
+_LT_CC_BASENAME([$compiler])
+_LT_TAGVAR(lt_cv_prog_compiler_c_o, $1)=yes
+
+if test -n "$compiler"; then
+  :
+  _LT_CONFIG($1)
+fi
+
+GCC=$lt_save_GCC
+AC_LANG_RESTORE
+CC=$lt_save_CC
+CFLAGS=$lt_save_CFLAGS
+])# _LT_LANG_RC_CONFIG
+
+
+# LT_PROG_GCJ
+# -----------
+AC_DEFUN([LT_PROG_GCJ],
+[m4_ifdef([AC_PROG_GCJ], [AC_PROG_GCJ],
+  [m4_ifdef([A][M_PROG_GCJ], [A][M_PROG_GCJ],
+    [AC_CHECK_TOOL(GCJ, gcj,)
+      test set = "${GCJFLAGS+set}" || GCJFLAGS="-g -O2"
+      AC_SUBST(GCJFLAGS)])])[]dnl
+])
+
+# Old name:
+AU_ALIAS([LT_AC_PROG_GCJ], [LT_PROG_GCJ])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([LT_AC_PROG_GCJ], [])
+
+
+# LT_PROG_GO
+# ----------
+AC_DEFUN([LT_PROG_GO],
+[AC_CHECK_TOOL(GOC, gccgo,)
+])
+
+
+# LT_PROG_RC
+# ----------
+AC_DEFUN([LT_PROG_RC],
+[AC_CHECK_TOOL(RC, windres,)
+])
+
+# Old name:
+AU_ALIAS([LT_AC_PROG_RC], [LT_PROG_RC])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([LT_AC_PROG_RC], [])
+
+
+# _LT_DECL_EGREP
+# --------------
+# If we don't have a new enough Autoconf to choose the best grep
+# available, choose the one first in the user's PATH.
+m4_defun([_LT_DECL_EGREP],
+[AC_REQUIRE([AC_PROG_EGREP])dnl
+AC_REQUIRE([AC_PROG_FGREP])dnl
+test -z "$GREP" && GREP=grep
+_LT_DECL([], [GREP], [1], [A grep program that handles long lines])
+_LT_DECL([], [EGREP], [1], [An ERE matcher])
+_LT_DECL([], [FGREP], [1], [A literal string matcher])
+dnl Non-bleeding-edge autoconf doesn't subst GREP, so do it here too
+AC_SUBST([GREP])
+])
+
+
+# _LT_DECL_OBJDUMP
+# --------------
+# If we don't have a new enough Autoconf to choose the best objdump
+# available, choose the one first in the user's PATH.
+m4_defun([_LT_DECL_OBJDUMP],
+[AC_CHECK_TOOL(OBJDUMP, objdump, false)
+test -z "$OBJDUMP" && OBJDUMP=objdump
+_LT_DECL([], [OBJDUMP], [1], [An object symbol dumper])
+AC_SUBST([OBJDUMP])
+])
+
+# _LT_DECL_DLLTOOL
+# ----------------
+# Ensure DLLTOOL variable is set.
+m4_defun([_LT_DECL_DLLTOOL],
+[AC_CHECK_TOOL(DLLTOOL, dlltool, false)
+test -z "$DLLTOOL" && DLLTOOL=dlltool
+_LT_DECL([], [DLLTOOL], [1], [DLL creation program])
+AC_SUBST([DLLTOOL])
+])
+
+# _LT_DECL_SED
+# ------------
+# Check for a fully-functional sed program, that truncates
+# as few characters as possible.  Prefer GNU sed if found.
+m4_defun([_LT_DECL_SED],
+[AC_PROG_SED
+test -z "$SED" && SED=sed
+Xsed="$SED -e 1s/^X//"
+_LT_DECL([], [SED], [1], [A sed program that does not truncate output])
+_LT_DECL([], [Xsed], ["\$SED -e 1s/^X//"],
+    [Sed that helps us avoid accidentally triggering echo(1) options like -n])
+])# _LT_DECL_SED
+
+m4_ifndef([AC_PROG_SED], [
+############################################################
+# NOTE: This macro has been submitted for inclusion into   #
+#  GNU Autoconf as AC_PROG_SED.  When it is available in   #
+#  a released version of Autoconf we should remove this    #
+#  macro and use it instead.                               #
+############################################################
+
+m4_defun([AC_PROG_SED],
+[AC_MSG_CHECKING([for a sed that does not truncate output])
+AC_CACHE_VAL(lt_cv_path_SED,
+[# Loop through the user's path and test for sed and gsed.
+# Then use that list of sed's as ones to test for truncation.
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+  for lt_ac_prog in sed gsed; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      if $as_executable_p "$as_dir/$lt_ac_prog$ac_exec_ext"; then
+        lt_ac_sed_list="$lt_ac_sed_list $as_dir/$lt_ac_prog$ac_exec_ext"
+      fi
+    done
+  done
+done
+IFS=$as_save_IFS
+lt_ac_max=0
+lt_ac_count=0
+# Add /usr/xpg4/bin/sed as it is typically found on Solaris
+# along with /bin/sed that truncates output.
+for lt_ac_sed in $lt_ac_sed_list /usr/xpg4/bin/sed; do
+  test ! -f "$lt_ac_sed" && continue
+  cat /dev/null > conftest.in
+  lt_ac_count=0
+  echo $ECHO_N "0123456789$ECHO_C" >conftest.in
+  # Check for GNU sed and select it if it is found.
+  if "$lt_ac_sed" --version 2>&1 < /dev/null | grep 'GNU' > /dev/null; then
+    lt_cv_path_SED=$lt_ac_sed
+    break
+  fi
+  while true; do
+    cat conftest.in conftest.in >conftest.tmp
+    mv conftest.tmp conftest.in
+    cp conftest.in conftest.nl
+    echo >>conftest.nl
+    $lt_ac_sed -e 's/a$//' < conftest.nl >conftest.out || break
+    cmp -s conftest.out conftest.nl || break
+    # 10000 chars as input seems more than enough
+    test 10 -lt "$lt_ac_count" && break
+    lt_ac_count=`expr $lt_ac_count + 1`
+    if test "$lt_ac_count" -gt "$lt_ac_max"; then
+      lt_ac_max=$lt_ac_count
+      lt_cv_path_SED=$lt_ac_sed
+    fi
+  done
+done
+])
+SED=$lt_cv_path_SED
+AC_SUBST([SED])
+AC_MSG_RESULT([$SED])
+])#AC_PROG_SED
+])#m4_ifndef
+
+# Old name:
+AU_ALIAS([LT_AC_PROG_SED], [AC_PROG_SED])
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([LT_AC_PROG_SED], [])
+
+
+# _LT_CHECK_SHELL_FEATURES
+# ------------------------
+# Find out whether the shell is Bourne or XSI compatible,
+# or has some other useful features.
+m4_defun([_LT_CHECK_SHELL_FEATURES],
+[if ( (MAIL=60; unset MAIL) || exit) >/dev/null 2>&1; then
+  lt_unset=unset
+else
+  lt_unset=false
+fi
+_LT_DECL([], [lt_unset], [0], [whether the shell understands "unset"])dnl
+
+# test EBCDIC or ASCII
+case `echo X|tr X '\101'` in
+ A) # ASCII based system
+    # \n is not interpreted correctly by Solaris 8 /usr/ucb/tr
+  lt_SP2NL='tr \040 \012'
+  lt_NL2SP='tr \015\012 \040\040'
+  ;;
+ *) # EBCDIC based system
+  lt_SP2NL='tr \100 \n'
+  lt_NL2SP='tr \r\n \100\100'
+  ;;
+esac
+_LT_DECL([SP2NL], [lt_SP2NL], [1], [turn spaces into newlines])dnl
+_LT_DECL([NL2SP], [lt_NL2SP], [1], [turn newlines into spaces])dnl
+])# _LT_CHECK_SHELL_FEATURES
+
+
+# _LT_PATH_CONVERSION_FUNCTIONS
+# -----------------------------
+# Determine what file name conversion functions should be used by
+# func_to_host_file (and, implicitly, by func_to_host_path).  These are needed
+# for certain cross-compile configurations and native mingw.
+m4_defun([_LT_PATH_CONVERSION_FUNCTIONS],
+[AC_REQUIRE([AC_CANONICAL_HOST])dnl
+AC_REQUIRE([AC_CANONICAL_BUILD])dnl
+AC_MSG_CHECKING([how to convert $build file names to $host format])
+AC_CACHE_VAL(lt_cv_to_host_file_cmd,
+[case $host in
+  *-*-mingw* )
+    case $build in
+      *-*-mingw* ) # actually msys
+        lt_cv_to_host_file_cmd=func_convert_file_msys_to_w32
+        ;;
+      *-*-cygwin* )
+        lt_cv_to_host_file_cmd=func_convert_file_cygwin_to_w32
+        ;;
+      * ) # otherwise, assume *nix
+        lt_cv_to_host_file_cmd=func_convert_file_nix_to_w32
+        ;;
+    esac
+    ;;
+  *-*-cygwin* )
+    case $build in
+      *-*-mingw* ) # actually msys
+        lt_cv_to_host_file_cmd=func_convert_file_msys_to_cygwin
+        ;;
+      *-*-cygwin* )
+        lt_cv_to_host_file_cmd=func_convert_file_noop
+        ;;
+      * ) # otherwise, assume *nix
+        lt_cv_to_host_file_cmd=func_convert_file_nix_to_cygwin
+        ;;
+    esac
+    ;;
+  * ) # unhandled hosts (and "normal" native builds)
+    lt_cv_to_host_file_cmd=func_convert_file_noop
+    ;;
+esac
+])
+to_host_file_cmd=$lt_cv_to_host_file_cmd
+AC_MSG_RESULT([$lt_cv_to_host_file_cmd])
+_LT_DECL([to_host_file_cmd], [lt_cv_to_host_file_cmd],
+         [0], [convert $build file names to $host format])dnl
+
+AC_MSG_CHECKING([how to convert $build file names to toolchain format])
+AC_CACHE_VAL(lt_cv_to_tool_file_cmd,
+[#assume ordinary cross tools, or native build.
+lt_cv_to_tool_file_cmd=func_convert_file_noop
+case $host in
+  *-*-mingw* )
+    case $build in
+      *-*-mingw* ) # actually msys
+        lt_cv_to_tool_file_cmd=func_convert_file_msys_to_w32
+        ;;
+    esac
+    ;;
+esac
+])
+to_tool_file_cmd=$lt_cv_to_tool_file_cmd
+AC_MSG_RESULT([$lt_cv_to_tool_file_cmd])
+_LT_DECL([to_tool_file_cmd], [lt_cv_to_tool_file_cmd],
+         [0], [convert $build files to toolchain format])dnl
+])# _LT_PATH_CONVERSION_FUNCTIONS
diff --git a/extern/libpng/scripts/ltoptions.m4 b/extern/libpng/scripts/ltoptions.m4
new file mode 100644
index 0000000000..94b0829766
--- /dev/null
+++ b/extern/libpng/scripts/ltoptions.m4
@@ -0,0 +1,437 @@
+# Helper functions for option handling.                    -*- Autoconf -*-
+#
+#   Copyright (C) 2004-2005, 2007-2009, 2011-2015 Free Software
+#   Foundation, Inc.
+#   Written by Gary V. Vaughan, 2004
+#
+# This file is free software; the Free Software Foundation gives
+# unlimited permission to copy and/or distribute it, with or without
+# modifications, as long as this notice is preserved.
+
+# serial 8 ltoptions.m4
+
+# This is to help aclocal find these macros, as it can't see m4_define.
+AC_DEFUN([LTOPTIONS_VERSION], [m4_if([1])])
+
+
+# _LT_MANGLE_OPTION(MACRO-NAME, OPTION-NAME)
+# ------------------------------------------
+m4_define([_LT_MANGLE_OPTION],
+[[_LT_OPTION_]m4_bpatsubst($1__$2, [[^a-zA-Z0-9_]], [_])])
+
+
+# _LT_SET_OPTION(MACRO-NAME, OPTION-NAME)
+# ---------------------------------------
+# Set option OPTION-NAME for macro MACRO-NAME, and if there is a
+# matching handler defined, dispatch to it.  Other OPTION-NAMEs are
+# saved as a flag.
+m4_define([_LT_SET_OPTION],
+[m4_define(_LT_MANGLE_OPTION([$1], [$2]))dnl
+m4_ifdef(_LT_MANGLE_DEFUN([$1], [$2]),
+        _LT_MANGLE_DEFUN([$1], [$2]),
+    [m4_warning([Unknown $1 option '$2'])])[]dnl
+])
+
+
+# _LT_IF_OPTION(MACRO-NAME, OPTION-NAME, IF-SET, [IF-NOT-SET])
+# ------------------------------------------------------------
+# Execute IF-SET if OPTION is set, IF-NOT-SET otherwise.
+m4_define([_LT_IF_OPTION],
+[m4_ifdef(_LT_MANGLE_OPTION([$1], [$2]), [$3], [$4])])
+
+
+# _LT_UNLESS_OPTIONS(MACRO-NAME, OPTION-LIST, IF-NOT-SET)
+# -------------------------------------------------------
+# Execute IF-NOT-SET unless all options in OPTION-LIST for MACRO-NAME
+# are set.
+m4_define([_LT_UNLESS_OPTIONS],
+[m4_foreach([_LT_Option], m4_split(m4_normalize([$2])),
+	    [m4_ifdef(_LT_MANGLE_OPTION([$1], _LT_Option),
+		      [m4_define([$0_found])])])[]dnl
+m4_ifdef([$0_found], [m4_undefine([$0_found])], [$3
+])[]dnl
+])
+
+
+# _LT_SET_OPTIONS(MACRO-NAME, OPTION-LIST)
+# ----------------------------------------
+# OPTION-LIST is a space-separated list of Libtool options associated
+# with MACRO-NAME.  If any OPTION has a matching handler declared with
+# LT_OPTION_DEFINE, dispatch to that macro; otherwise complain about
+# the unknown option and exit.
+m4_defun([_LT_SET_OPTIONS],
+[# Set options
+m4_foreach([_LT_Option], m4_split(m4_normalize([$2])),
+    [_LT_SET_OPTION([$1], _LT_Option)])
+
+m4_if([$1],[LT_INIT],[
+  dnl
+  dnl Simply set some default values (i.e off) if boolean options were not
+  dnl specified:
+  _LT_UNLESS_OPTIONS([LT_INIT], [dlopen], [enable_dlopen=no
+  ])
+  _LT_UNLESS_OPTIONS([LT_INIT], [win32-dll], [enable_win32_dll=no
+  ])
+  dnl
+  dnl If no reference was made to various pairs of opposing options, then
+  dnl we run the default mode handler for the pair.  For example, if neither
+  dnl 'shared' nor 'disable-shared' was passed, we enable building of shared
+  dnl archives by default:
+  _LT_UNLESS_OPTIONS([LT_INIT], [shared disable-shared], [_LT_ENABLE_SHARED])
+  _LT_UNLESS_OPTIONS([LT_INIT], [static disable-static], [_LT_ENABLE_STATIC])
+  _LT_UNLESS_OPTIONS([LT_INIT], [pic-only no-pic], [_LT_WITH_PIC])
+  _LT_UNLESS_OPTIONS([LT_INIT], [fast-install disable-fast-install],
+		   [_LT_ENABLE_FAST_INSTALL])
+  _LT_UNLESS_OPTIONS([LT_INIT], [aix-soname=aix aix-soname=both aix-soname=svr4],
+		   [_LT_WITH_AIX_SONAME([aix])])
+  ])
+])# _LT_SET_OPTIONS
+
+
+## --------------------------------- ##
+## Macros to handle LT_INIT options. ##
+## --------------------------------- ##
+
+# _LT_MANGLE_DEFUN(MACRO-NAME, OPTION-NAME)
+# -----------------------------------------
+m4_define([_LT_MANGLE_DEFUN],
+[[_LT_OPTION_DEFUN_]m4_bpatsubst(m4_toupper([$1__$2]), [[^A-Z0-9_]], [_])])
+
+
+# LT_OPTION_DEFINE(MACRO-NAME, OPTION-NAME, CODE)
+# -----------------------------------------------
+m4_define([LT_OPTION_DEFINE],
+[m4_define(_LT_MANGLE_DEFUN([$1], [$2]), [$3])[]dnl
+])# LT_OPTION_DEFINE
+
+
+# dlopen
+# ------
+LT_OPTION_DEFINE([LT_INIT], [dlopen], [enable_dlopen=yes
+])
+
+AU_DEFUN([AC_LIBTOOL_DLOPEN],
+[_LT_SET_OPTION([LT_INIT], [dlopen])
+AC_DIAGNOSE([obsolete],
+[$0: Remove this warning and the call to _LT_SET_OPTION when you
+put the 'dlopen' option into LT_INIT's first parameter.])
+])
+
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_LIBTOOL_DLOPEN], [])
+
+
+# win32-dll
+# ---------
+# Declare package support for building win32 dll's.
+LT_OPTION_DEFINE([LT_INIT], [win32-dll],
+[enable_win32_dll=yes
+
+case $host in
+*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-cegcc*)
+  AC_CHECK_TOOL(AS, as, false)
+  AC_CHECK_TOOL(DLLTOOL, dlltool, false)
+  AC_CHECK_TOOL(OBJDUMP, objdump, false)
+  ;;
+esac
+
+test -z "$AS" && AS=as
+_LT_DECL([], [AS],      [1], [Assembler program])dnl
+
+test -z "$DLLTOOL" && DLLTOOL=dlltool
+_LT_DECL([], [DLLTOOL], [1], [DLL creation program])dnl
+
+test -z "$OBJDUMP" && OBJDUMP=objdump
+_LT_DECL([], [OBJDUMP], [1], [Object dumper program])dnl
+])# win32-dll
+
+AU_DEFUN([AC_LIBTOOL_WIN32_DLL],
+[AC_REQUIRE([AC_CANONICAL_HOST])dnl
+_LT_SET_OPTION([LT_INIT], [win32-dll])
+AC_DIAGNOSE([obsolete],
+[$0: Remove this warning and the call to _LT_SET_OPTION when you
+put the 'win32-dll' option into LT_INIT's first parameter.])
+])
+
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_LIBTOOL_WIN32_DLL], [])
+
+
+# _LT_ENABLE_SHARED([DEFAULT])
+# ----------------------------
+# implement the --enable-shared flag, and supports the 'shared' and
+# 'disable-shared' LT_INIT options.
+# DEFAULT is either 'yes' or 'no'.  If omitted, it defaults to 'yes'.
+m4_define([_LT_ENABLE_SHARED],
+[m4_define([_LT_ENABLE_SHARED_DEFAULT], [m4_if($1, no, no, yes)])dnl
+AC_ARG_ENABLE([shared],
+    [AS_HELP_STRING([--enable-shared@<:@=PKGS@:>@],
+	[build shared libraries @<:@default=]_LT_ENABLE_SHARED_DEFAULT[@:>@])],
+    [p=${PACKAGE-default}
+    case $enableval in
+    yes) enable_shared=yes ;;
+    no) enable_shared=no ;;
+    *)
+      enable_shared=no
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for pkg in $enableval; do
+	IFS=$lt_save_ifs
+	if test "X$pkg" = "X$p"; then
+	  enable_shared=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac],
+    [enable_shared=]_LT_ENABLE_SHARED_DEFAULT)
+
+    _LT_DECL([build_libtool_libs], [enable_shared], [0],
+	[Whether or not to build shared libraries])
+])# _LT_ENABLE_SHARED
+
+LT_OPTION_DEFINE([LT_INIT], [shared], [_LT_ENABLE_SHARED([yes])])
+LT_OPTION_DEFINE([LT_INIT], [disable-shared], [_LT_ENABLE_SHARED([no])])
+
+# Old names:
+AC_DEFUN([AC_ENABLE_SHARED],
+[_LT_SET_OPTION([LT_INIT], m4_if([$1], [no], [disable-])[shared])
+])
+
+AC_DEFUN([AC_DISABLE_SHARED],
+[_LT_SET_OPTION([LT_INIT], [disable-shared])
+])
+
+AU_DEFUN([AM_ENABLE_SHARED], [AC_ENABLE_SHARED($@)])
+AU_DEFUN([AM_DISABLE_SHARED], [AC_DISABLE_SHARED($@)])
+
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AM_ENABLE_SHARED], [])
+dnl AC_DEFUN([AM_DISABLE_SHARED], [])
+
+
+
+# _LT_ENABLE_STATIC([DEFAULT])
+# ----------------------------
+# implement the --enable-static flag, and support the 'static' and
+# 'disable-static' LT_INIT options.
+# DEFAULT is either 'yes' or 'no'.  If omitted, it defaults to 'yes'.
+m4_define([_LT_ENABLE_STATIC],
+[m4_define([_LT_ENABLE_STATIC_DEFAULT], [m4_if($1, no, no, yes)])dnl
+AC_ARG_ENABLE([static],
+    [AS_HELP_STRING([--enable-static@<:@=PKGS@:>@],
+	[build static libraries @<:@default=]_LT_ENABLE_STATIC_DEFAULT[@:>@])],
+    [p=${PACKAGE-default}
+    case $enableval in
+    yes) enable_static=yes ;;
+    no) enable_static=no ;;
+    *)
+     enable_static=no
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for pkg in $enableval; do
+	IFS=$lt_save_ifs
+	if test "X$pkg" = "X$p"; then
+	  enable_static=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac],
+    [enable_static=]_LT_ENABLE_STATIC_DEFAULT)
+
+    _LT_DECL([build_old_libs], [enable_static], [0],
+	[Whether or not to build static libraries])
+])# _LT_ENABLE_STATIC
+
+LT_OPTION_DEFINE([LT_INIT], [static], [_LT_ENABLE_STATIC([yes])])
+LT_OPTION_DEFINE([LT_INIT], [disable-static], [_LT_ENABLE_STATIC([no])])
+
+# Old names:
+AC_DEFUN([AC_ENABLE_STATIC],
+[_LT_SET_OPTION([LT_INIT], m4_if([$1], [no], [disable-])[static])
+])
+
+AC_DEFUN([AC_DISABLE_STATIC],
+[_LT_SET_OPTION([LT_INIT], [disable-static])
+])
+
+AU_DEFUN([AM_ENABLE_STATIC], [AC_ENABLE_STATIC($@)])
+AU_DEFUN([AM_DISABLE_STATIC], [AC_DISABLE_STATIC($@)])
+
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AM_ENABLE_STATIC], [])
+dnl AC_DEFUN([AM_DISABLE_STATIC], [])
+
+
+
+# _LT_ENABLE_FAST_INSTALL([DEFAULT])
+# ----------------------------------
+# implement the --enable-fast-install flag, and support the 'fast-install'
+# and 'disable-fast-install' LT_INIT options.
+# DEFAULT is either 'yes' or 'no'.  If omitted, it defaults to 'yes'.
+m4_define([_LT_ENABLE_FAST_INSTALL],
+[m4_define([_LT_ENABLE_FAST_INSTALL_DEFAULT], [m4_if($1, no, no, yes)])dnl
+AC_ARG_ENABLE([fast-install],
+    [AS_HELP_STRING([--enable-fast-install@<:@=PKGS@:>@],
+    [optimize for fast installation @<:@default=]_LT_ENABLE_FAST_INSTALL_DEFAULT[@:>@])],
+    [p=${PACKAGE-default}
+    case $enableval in
+    yes) enable_fast_install=yes ;;
+    no) enable_fast_install=no ;;
+    *)
+      enable_fast_install=no
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for pkg in $enableval; do
+	IFS=$lt_save_ifs
+	if test "X$pkg" = "X$p"; then
+	  enable_fast_install=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac],
+    [enable_fast_install=]_LT_ENABLE_FAST_INSTALL_DEFAULT)
+
+_LT_DECL([fast_install], [enable_fast_install], [0],
+	 [Whether or not to optimize for fast installation])dnl
+])# _LT_ENABLE_FAST_INSTALL
+
+LT_OPTION_DEFINE([LT_INIT], [fast-install], [_LT_ENABLE_FAST_INSTALL([yes])])
+LT_OPTION_DEFINE([LT_INIT], [disable-fast-install], [_LT_ENABLE_FAST_INSTALL([no])])
+
+# Old names:
+AU_DEFUN([AC_ENABLE_FAST_INSTALL],
+[_LT_SET_OPTION([LT_INIT], m4_if([$1], [no], [disable-])[fast-install])
+AC_DIAGNOSE([obsolete],
+[$0: Remove this warning and the call to _LT_SET_OPTION when you put
+the 'fast-install' option into LT_INIT's first parameter.])
+])
+
+AU_DEFUN([AC_DISABLE_FAST_INSTALL],
+[_LT_SET_OPTION([LT_INIT], [disable-fast-install])
+AC_DIAGNOSE([obsolete],
+[$0: Remove this warning and the call to _LT_SET_OPTION when you put
+the 'disable-fast-install' option into LT_INIT's first parameter.])
+])
+
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_ENABLE_FAST_INSTALL], [])
+dnl AC_DEFUN([AM_DISABLE_FAST_INSTALL], [])
+
+
+# _LT_WITH_AIX_SONAME([DEFAULT])
+# ----------------------------------
+# implement the --with-aix-soname flag, and support the `aix-soname=aix'
+# and `aix-soname=both' and `aix-soname=svr4' LT_INIT options. DEFAULT
+# is either `aix', `both' or `svr4'.  If omitted, it defaults to `aix'.
+m4_define([_LT_WITH_AIX_SONAME],
+[m4_define([_LT_WITH_AIX_SONAME_DEFAULT], [m4_if($1, svr4, svr4, m4_if($1, both, both, aix))])dnl
+shared_archive_member_spec=
+case $host,$enable_shared in
+power*-*-aix[[5-9]]*,yes)
+  AC_MSG_CHECKING([which variant of shared library versioning to provide])
+  AC_ARG_WITH([aix-soname],
+    [AS_HELP_STRING([--with-aix-soname=aix|svr4|both],
+      [shared library versioning (aka "SONAME") variant to provide on AIX, @<:@default=]_LT_WITH_AIX_SONAME_DEFAULT[@:>@.])],
+    [case $withval in
+    aix|svr4|both)
+      ;;
+    *)
+      AC_MSG_ERROR([Unknown argument to --with-aix-soname])
+      ;;
+    esac
+    lt_cv_with_aix_soname=$with_aix_soname],
+    [AC_CACHE_VAL([lt_cv_with_aix_soname],
+      [lt_cv_with_aix_soname=]_LT_WITH_AIX_SONAME_DEFAULT)
+    with_aix_soname=$lt_cv_with_aix_soname])
+  AC_MSG_RESULT([$with_aix_soname])
+  if test aix != "$with_aix_soname"; then
+    # For the AIX way of multilib, we name the shared archive member
+    # based on the bitwidth used, traditionally 'shr.o' or 'shr_64.o',
+    # and 'shr.imp' or 'shr_64.imp', respectively, for the Import File.
+    # Even when GNU compilers ignore OBJECT_MODE but need '-maix64' flag,
+    # the AIX toolchain works better with OBJECT_MODE set (default 32).
+    if test 64 = "${OBJECT_MODE-32}"; then
+      shared_archive_member_spec=shr_64
+    else
+      shared_archive_member_spec=shr
+    fi
+  fi
+  ;;
+*)
+  with_aix_soname=aix
+  ;;
+esac
+
+_LT_DECL([], [shared_archive_member_spec], [0],
+    [Shared archive member basename, for filename based shared library versioning on AIX])dnl
+])# _LT_WITH_AIX_SONAME
+
+LT_OPTION_DEFINE([LT_INIT], [aix-soname=aix], [_LT_WITH_AIX_SONAME([aix])])
+LT_OPTION_DEFINE([LT_INIT], [aix-soname=both], [_LT_WITH_AIX_SONAME([both])])
+LT_OPTION_DEFINE([LT_INIT], [aix-soname=svr4], [_LT_WITH_AIX_SONAME([svr4])])
+
+
+# _LT_WITH_PIC([MODE])
+# --------------------
+# implement the --with-pic flag, and support the 'pic-only' and 'no-pic'
+# LT_INIT options.
+# MODE is either 'yes' or 'no'.  If omitted, it defaults to 'both'.
+m4_define([_LT_WITH_PIC],
+[AC_ARG_WITH([pic],
+    [AS_HELP_STRING([--with-pic@<:@=PKGS@:>@],
+	[try to use only PIC/non-PIC objects @<:@default=use both@:>@])],
+    [lt_p=${PACKAGE-default}
+    case $withval in
+    yes|no) pic_mode=$withval ;;
+    *)
+      pic_mode=default
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for lt_pkg in $withval; do
+	IFS=$lt_save_ifs
+	if test "X$lt_pkg" = "X$lt_p"; then
+	  pic_mode=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac],
+    [pic_mode=m4_default([$1], [default])])
+
+_LT_DECL([], [pic_mode], [0], [What type of objects to build])dnl
+])# _LT_WITH_PIC
+
+LT_OPTION_DEFINE([LT_INIT], [pic-only], [_LT_WITH_PIC([yes])])
+LT_OPTION_DEFINE([LT_INIT], [no-pic], [_LT_WITH_PIC([no])])
+
+# Old name:
+AU_DEFUN([AC_LIBTOOL_PICMODE],
+[_LT_SET_OPTION([LT_INIT], [pic-only])
+AC_DIAGNOSE([obsolete],
+[$0: Remove this warning and the call to _LT_SET_OPTION when you
+put the 'pic-only' option into LT_INIT's first parameter.])
+])
+
+dnl aclocal-1.4 backwards compatibility:
+dnl AC_DEFUN([AC_LIBTOOL_PICMODE], [])
+
+## ----------------- ##
+## LTDL_INIT Options ##
+## ----------------- ##
+
+m4_define([_LTDL_MODE], [])
+LT_OPTION_DEFINE([LTDL_INIT], [nonrecursive],
+		 [m4_define([_LTDL_MODE], [nonrecursive])])
+LT_OPTION_DEFINE([LTDL_INIT], [recursive],
+		 [m4_define([_LTDL_MODE], [recursive])])
+LT_OPTION_DEFINE([LTDL_INIT], [subproject],
+		 [m4_define([_LTDL_MODE], [subproject])])
+
+m4_define([_LTDL_TYPE], [])
+LT_OPTION_DEFINE([LTDL_INIT], [installable],
+		 [m4_define([_LTDL_TYPE], [installable])])
+LT_OPTION_DEFINE([LTDL_INIT], [convenience],
+		 [m4_define([_LTDL_TYPE], [convenience])])
diff --git a/extern/libpng/scripts/ltsugar.m4 b/extern/libpng/scripts/ltsugar.m4
new file mode 100644
index 0000000000..48bc9344a4
--- /dev/null
+++ b/extern/libpng/scripts/ltsugar.m4
@@ -0,0 +1,124 @@
+# ltsugar.m4 -- libtool m4 base layer.                         -*-Autoconf-*-
+#
+# Copyright (C) 2004-2005, 2007-2008, 2011-2015 Free Software
+# Foundation, Inc.
+# Written by Gary V. Vaughan, 2004
+#
+# This file is free software; the Free Software Foundation gives
+# unlimited permission to copy and/or distribute it, with or without
+# modifications, as long as this notice is preserved.
+
+# serial 6 ltsugar.m4
+
+# This is to help aclocal find these macros, as it can't see m4_define.
+AC_DEFUN([LTSUGAR_VERSION], [m4_if([0.1])])
+
+
+# lt_join(SEP, ARG1, [ARG2...])
+# -----------------------------
+# Produce ARG1SEPARG2...SEPARGn, omitting [] arguments and their
+# associated separator.
+# Needed until we can rely on m4_join from Autoconf 2.62, since all earlier
+# versions in m4sugar had bugs.
+m4_define([lt_join],
+[m4_if([$#], [1], [],
+       [$#], [2], [[$2]],
+       [m4_if([$2], [], [], [[$2]_])$0([$1], m4_shift(m4_shift($@)))])])
+m4_define([_lt_join],
+[m4_if([$#$2], [2], [],
+       [m4_if([$2], [], [], [[$1$2]])$0([$1], m4_shift(m4_shift($@)))])])
+
+
+# lt_car(LIST)
+# lt_cdr(LIST)
+# ------------
+# Manipulate m4 lists.
+# These macros are necessary as long as will still need to support
+# Autoconf-2.59, which quotes differently.
+m4_define([lt_car], [[$1]])
+m4_define([lt_cdr],
+[m4_if([$#], 0, [m4_fatal([$0: cannot be called without arguments])],
+       [$#], 1, [],
+       [m4_dquote(m4_shift($@))])])
+m4_define([lt_unquote], $1)
+
+
+# lt_append(MACRO-NAME, STRING, [SEPARATOR])
+# ------------------------------------------
+# Redefine MACRO-NAME to hold its former content plus 'SEPARATOR''STRING'.
+# Note that neither SEPARATOR nor STRING are expanded; they are appended
+# to MACRO-NAME as is (leaving the expansion for when MACRO-NAME is invoked).
+# No SEPARATOR is output if MACRO-NAME was previously undefined (different
+# than defined and empty).
+#
+# This macro is needed until we can rely on Autoconf 2.62, since earlier
+# versions of m4sugar mistakenly expanded SEPARATOR but not STRING.
+m4_define([lt_append],
+[m4_define([$1],
+	   m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
+
+
+
+# lt_combine(SEP, PREFIX-LIST, INFIX, SUFFIX1, [SUFFIX2...])
+# ----------------------------------------------------------
+# Produce a SEP delimited list of all paired combinations of elements of
+# PREFIX-LIST with SUFFIX1 through SUFFIXn.  Each element of the list
+# has the form PREFIXmINFIXSUFFIXn.
+# Needed until we can rely on m4_combine added in Autoconf 2.62.
+m4_define([lt_combine],
+[m4_if(m4_eval([$# > 3]), [1],
+       [m4_pushdef([_Lt_sep], [m4_define([_Lt_sep], m4_defn([lt_car]))])]]dnl
+[[m4_foreach([_Lt_prefix], [$2],
+	     [m4_foreach([_Lt_suffix],
+		]m4_dquote(m4_dquote(m4_shift(m4_shift(m4_shift($@)))))[,
+	[_Lt_sep([$1])[]m4_defn([_Lt_prefix])[$3]m4_defn([_Lt_suffix])])])])])
+
+
+# lt_if_append_uniq(MACRO-NAME, VARNAME, [SEPARATOR], [UNIQ], [NOT-UNIQ])
+# -----------------------------------------------------------------------
+# Iff MACRO-NAME does not yet contain VARNAME, then append it (delimited
+# by SEPARATOR if supplied) and expand UNIQ, else NOT-UNIQ.
+m4_define([lt_if_append_uniq],
+[m4_ifdef([$1],
+	  [m4_if(m4_index([$3]m4_defn([$1])[$3], [$3$2$3]), [-1],
+		 [lt_append([$1], [$2], [$3])$4],
+		 [$5])],
+	  [lt_append([$1], [$2], [$3])$4])])
+
+
+# lt_dict_add(DICT, KEY, VALUE)
+# -----------------------------
+m4_define([lt_dict_add],
+[m4_define([$1($2)], [$3])])
+
+
+# lt_dict_add_subkey(DICT, KEY, SUBKEY, VALUE)
+# --------------------------------------------
+m4_define([lt_dict_add_subkey],
+[m4_define([$1($2:$3)], [$4])])
+
+
+# lt_dict_fetch(DICT, KEY, [SUBKEY])
+# ----------------------------------
+m4_define([lt_dict_fetch],
+[m4_ifval([$3],
+	m4_ifdef([$1($2:$3)], [m4_defn([$1($2:$3)])]),
+    m4_ifdef([$1($2)], [m4_defn([$1($2)])]))])
+
+
+# lt_if_dict_fetch(DICT, KEY, [SUBKEY], VALUE, IF-TRUE, [IF-FALSE])
+# -----------------------------------------------------------------
+m4_define([lt_if_dict_fetch],
+[m4_if(lt_dict_fetch([$1], [$2], [$3]), [$4],
+	[$5],
+    [$6])])
+
+
+# lt_dict_filter(DICT, [SUBKEY], VALUE, [SEPARATOR], KEY, [...])
+# --------------------------------------------------------------
+m4_define([lt_dict_filter],
+[m4_if([$5], [], [],
+  [lt_join(m4_quote(m4_default([$4], [[, ]])),
+           lt_unquote(m4_split(m4_normalize(m4_foreach(_Lt_key, lt_car([m4_shiftn(4, $@)]),
+		      [lt_if_dict_fetch([$1], _Lt_key, [$2], [$3], [_Lt_key ])])))))])[]dnl
+])
diff --git a/extern/libpng/scripts/ltversion.m4 b/extern/libpng/scripts/ltversion.m4
new file mode 100644
index 0000000000..fa04b52a3b
--- /dev/null
+++ b/extern/libpng/scripts/ltversion.m4
@@ -0,0 +1,23 @@
+# ltversion.m4 -- version numbers			-*- Autoconf -*-
+#
+#   Copyright (C) 2004, 2011-2015 Free Software Foundation, Inc.
+#   Written by Scott James Remnant, 2004
+#
+# This file is free software; the Free Software Foundation gives
+# unlimited permission to copy and/or distribute it, with or without
+# modifications, as long as this notice is preserved.
+
+# @configure_input@
+
+# serial 4179 ltversion.m4
+# This file is part of GNU Libtool
+
+m4_define([LT_PACKAGE_VERSION], [2.4.6])
+m4_define([LT_PACKAGE_REVISION], [2.4.6])
+
+AC_DEFUN([LTVERSION_VERSION],
+[macro_version='2.4.6'
+macro_revision='2.4.6'
+_LT_DECL(, macro_version, 0, [Which release of libtool.m4 was used?])
+_LT_DECL(, macro_revision, 0)
+])
diff --git a/extern/libpng/scripts/lt~obsolete.m4 b/extern/libpng/scripts/lt~obsolete.m4
new file mode 100644
index 0000000000..c6b26f88f6
--- /dev/null
+++ b/extern/libpng/scripts/lt~obsolete.m4
@@ -0,0 +1,99 @@
+# lt~obsolete.m4 -- aclocal satisfying obsolete definitions.    -*-Autoconf-*-
+#
+#   Copyright (C) 2004-2005, 2007, 2009, 2011-2015 Free Software
+#   Foundation, Inc.
+#   Written by Scott James Remnant, 2004.
+#
+# This file is free software; the Free Software Foundation gives
+# unlimited permission to copy and/or distribute it, with or without
+# modifications, as long as this notice is preserved.
+
+# serial 5 lt~obsolete.m4
+
+# These exist entirely to fool aclocal when bootstrapping libtool.
+#
+# In the past libtool.m4 has provided macros via AC_DEFUN (or AU_DEFUN),
+# which have later been changed to m4_define as they aren't part of the
+# exported API, or moved to Autoconf or Automake where they belong.
+#
+# The trouble is, aclocal is a bit thick.  It'll see the old AC_DEFUN
+# in /usr/share/aclocal/libtool.m4 and remember it, then when it sees us
+# using a macro with the same name in our local m4/libtool.m4 it'll
+# pull the old libtool.m4 in (it doesn't see our shiny new m4_define
+# and doesn't know about Autoconf macros at all.)
+#
+# So we provide this file, which has a silly filename so it's always
+# included after everything else.  This provides aclocal with the
+# AC_DEFUNs it wants, but when m4 processes it, it doesn't do anything
+# because those macros already exist, or will be overwritten later.
+# We use AC_DEFUN over AU_DEFUN for compatibility with aclocal-1.6.
+#
+# Anytime we withdraw an AC_DEFUN or AU_DEFUN, remember to add it here.
+# Yes, that means every name once taken will need to remain here until
+# we give up compatibility with versions before 1.7, at which point
+# we need to keep only those names which we still refer to.
+
+# This is to help aclocal find these macros, as it can't see m4_define.
+AC_DEFUN([LTOBSOLETE_VERSION], [m4_if([1])])
+
+m4_ifndef([AC_LIBTOOL_LINKER_OPTION],	[AC_DEFUN([AC_LIBTOOL_LINKER_OPTION])])
+m4_ifndef([AC_PROG_EGREP],		[AC_DEFUN([AC_PROG_EGREP])])
+m4_ifndef([_LT_AC_PROG_ECHO_BACKSLASH],	[AC_DEFUN([_LT_AC_PROG_ECHO_BACKSLASH])])
+m4_ifndef([_LT_AC_SHELL_INIT],		[AC_DEFUN([_LT_AC_SHELL_INIT])])
+m4_ifndef([_LT_AC_SYS_LIBPATH_AIX],	[AC_DEFUN([_LT_AC_SYS_LIBPATH_AIX])])
+m4_ifndef([_LT_PROG_LTMAIN],		[AC_DEFUN([_LT_PROG_LTMAIN])])
+m4_ifndef([_LT_AC_TAGVAR],		[AC_DEFUN([_LT_AC_TAGVAR])])
+m4_ifndef([AC_LTDL_ENABLE_INSTALL],	[AC_DEFUN([AC_LTDL_ENABLE_INSTALL])])
+m4_ifndef([AC_LTDL_PREOPEN],		[AC_DEFUN([AC_LTDL_PREOPEN])])
+m4_ifndef([_LT_AC_SYS_COMPILER],	[AC_DEFUN([_LT_AC_SYS_COMPILER])])
+m4_ifndef([_LT_AC_LOCK],		[AC_DEFUN([_LT_AC_LOCK])])
+m4_ifndef([AC_LIBTOOL_SYS_OLD_ARCHIVE],	[AC_DEFUN([AC_LIBTOOL_SYS_OLD_ARCHIVE])])
+m4_ifndef([_LT_AC_TRY_DLOPEN_SELF],	[AC_DEFUN([_LT_AC_TRY_DLOPEN_SELF])])
+m4_ifndef([AC_LIBTOOL_PROG_CC_C_O],	[AC_DEFUN([AC_LIBTOOL_PROG_CC_C_O])])
+m4_ifndef([AC_LIBTOOL_SYS_HARD_LINK_LOCKS], [AC_DEFUN([AC_LIBTOOL_SYS_HARD_LINK_LOCKS])])
+m4_ifndef([AC_LIBTOOL_OBJDIR],		[AC_DEFUN([AC_LIBTOOL_OBJDIR])])
+m4_ifndef([AC_LTDL_OBJDIR],		[AC_DEFUN([AC_LTDL_OBJDIR])])
+m4_ifndef([AC_LIBTOOL_PROG_LD_HARDCODE_LIBPATH], [AC_DEFUN([AC_LIBTOOL_PROG_LD_HARDCODE_LIBPATH])])
+m4_ifndef([AC_LIBTOOL_SYS_LIB_STRIP],	[AC_DEFUN([AC_LIBTOOL_SYS_LIB_STRIP])])
+m4_ifndef([AC_PATH_MAGIC],		[AC_DEFUN([AC_PATH_MAGIC])])
+m4_ifndef([AC_PROG_LD_GNU],		[AC_DEFUN([AC_PROG_LD_GNU])])
+m4_ifndef([AC_PROG_LD_RELOAD_FLAG],	[AC_DEFUN([AC_PROG_LD_RELOAD_FLAG])])
+m4_ifndef([AC_DEPLIBS_CHECK_METHOD],	[AC_DEFUN([AC_DEPLIBS_CHECK_METHOD])])
+m4_ifndef([AC_LIBTOOL_PROG_COMPILER_NO_RTTI], [AC_DEFUN([AC_LIBTOOL_PROG_COMPILER_NO_RTTI])])
+m4_ifndef([AC_LIBTOOL_SYS_GLOBAL_SYMBOL_PIPE], [AC_DEFUN([AC_LIBTOOL_SYS_GLOBAL_SYMBOL_PIPE])])
+m4_ifndef([AC_LIBTOOL_PROG_COMPILER_PIC], [AC_DEFUN([AC_LIBTOOL_PROG_COMPILER_PIC])])
+m4_ifndef([AC_LIBTOOL_PROG_LD_SHLIBS],	[AC_DEFUN([AC_LIBTOOL_PROG_LD_SHLIBS])])
+m4_ifndef([AC_LIBTOOL_POSTDEP_PREDEP],	[AC_DEFUN([AC_LIBTOOL_POSTDEP_PREDEP])])
+m4_ifndef([LT_AC_PROG_EGREP],		[AC_DEFUN([LT_AC_PROG_EGREP])])
+m4_ifndef([LT_AC_PROG_SED],		[AC_DEFUN([LT_AC_PROG_SED])])
+m4_ifndef([_LT_CC_BASENAME],		[AC_DEFUN([_LT_CC_BASENAME])])
+m4_ifndef([_LT_COMPILER_BOILERPLATE],	[AC_DEFUN([_LT_COMPILER_BOILERPLATE])])
+m4_ifndef([_LT_LINKER_BOILERPLATE],	[AC_DEFUN([_LT_LINKER_BOILERPLATE])])
+m4_ifndef([_AC_PROG_LIBTOOL],		[AC_DEFUN([_AC_PROG_LIBTOOL])])
+m4_ifndef([AC_LIBTOOL_SETUP],		[AC_DEFUN([AC_LIBTOOL_SETUP])])
+m4_ifndef([_LT_AC_CHECK_DLFCN],		[AC_DEFUN([_LT_AC_CHECK_DLFCN])])
+m4_ifndef([AC_LIBTOOL_SYS_DYNAMIC_LINKER],	[AC_DEFUN([AC_LIBTOOL_SYS_DYNAMIC_LINKER])])
+m4_ifndef([_LT_AC_TAGCONFIG],		[AC_DEFUN([_LT_AC_TAGCONFIG])])
+m4_ifndef([AC_DISABLE_FAST_INSTALL],	[AC_DEFUN([AC_DISABLE_FAST_INSTALL])])
+m4_ifndef([_LT_AC_LANG_CXX],		[AC_DEFUN([_LT_AC_LANG_CXX])])
+m4_ifndef([_LT_AC_LANG_F77],		[AC_DEFUN([_LT_AC_LANG_F77])])
+m4_ifndef([_LT_AC_LANG_GCJ],		[AC_DEFUN([_LT_AC_LANG_GCJ])])
+m4_ifndef([AC_LIBTOOL_LANG_C_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_C_CONFIG])])
+m4_ifndef([_LT_AC_LANG_C_CONFIG],	[AC_DEFUN([_LT_AC_LANG_C_CONFIG])])
+m4_ifndef([AC_LIBTOOL_LANG_CXX_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_CXX_CONFIG])])
+m4_ifndef([_LT_AC_LANG_CXX_CONFIG],	[AC_DEFUN([_LT_AC_LANG_CXX_CONFIG])])
+m4_ifndef([AC_LIBTOOL_LANG_F77_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_F77_CONFIG])])
+m4_ifndef([_LT_AC_LANG_F77_CONFIG],	[AC_DEFUN([_LT_AC_LANG_F77_CONFIG])])
+m4_ifndef([AC_LIBTOOL_LANG_GCJ_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_GCJ_CONFIG])])
+m4_ifndef([_LT_AC_LANG_GCJ_CONFIG],	[AC_DEFUN([_LT_AC_LANG_GCJ_CONFIG])])
+m4_ifndef([AC_LIBTOOL_LANG_RC_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_RC_CONFIG])])
+m4_ifndef([_LT_AC_LANG_RC_CONFIG],	[AC_DEFUN([_LT_AC_LANG_RC_CONFIG])])
+m4_ifndef([AC_LIBTOOL_CONFIG],		[AC_DEFUN([AC_LIBTOOL_CONFIG])])
+m4_ifndef([_LT_AC_FILE_LTDLL_C],	[AC_DEFUN([_LT_AC_FILE_LTDLL_C])])
+m4_ifndef([_LT_REQUIRED_DARWIN_CHECKS],	[AC_DEFUN([_LT_REQUIRED_DARWIN_CHECKS])])
+m4_ifndef([_LT_AC_PROG_CXXCPP],		[AC_DEFUN([_LT_AC_PROG_CXXCPP])])
+m4_ifndef([_LT_PREPARE_SED_QUOTE_VARS],	[AC_DEFUN([_LT_PREPARE_SED_QUOTE_VARS])])
+m4_ifndef([_LT_PROG_ECHO_BACKSLASH],	[AC_DEFUN([_LT_PROG_ECHO_BACKSLASH])])
+m4_ifndef([_LT_PROG_F77],		[AC_DEFUN([_LT_PROG_F77])])
+m4_ifndef([_LT_PROG_FC],		[AC_DEFUN([_LT_PROG_FC])])
+m4_ifndef([_LT_PROG_CXX],		[AC_DEFUN([_LT_PROG_CXX])])
diff --git a/extern/libpng/scripts/macro.lst b/extern/libpng/scripts/macro.lst
new file mode 100644
index 0000000000..57124b76a0
--- /dev/null
+++ b/extern/libpng/scripts/macro.lst
@@ -0,0 +1,3 @@
+get_uint_32(buf)
+get_uint_16(buf)
+get_int_32(buf)
diff --git a/extern/libpng/scripts/makefile.32sunu b/extern/libpng/scripts/makefile.32sunu
new file mode 100644
index 0000000000..c849ecd277
--- /dev/null
+++ b/extern/libpng/scripts/makefile.32sunu
@@ -0,0 +1,244 @@
+# makefile for libpng on Solaris 2.x with cc
+# Contributed by William L. Sebok, based on makefile.linux
+# Copyright (C) 2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1998 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+CC=cc
+AR_RC=ar rc
+MKDIR_P=mkdir -p
+LN_SF=ln -f -s
+RANLIB=echo
+RM_F=/bin/rm -f
+
+SUN_CC_FLAGS=-fast -xtarget=ultra
+SUN_LD_FLAGS=-fast -xtarget=ultra
+
+# where make install puts libpng.a, libpng16.so and libpng16/png.h
+prefix=/a
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located
+# Changing these to ../zlib poses a security risk.  If you want
+# to have zlib in an adjacent directory, specify the full path instead of "..".
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+
+ZLIBLIB=/usr/lib
+ZLIBINC=/usr/include
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=$(SUN_CC_FLAGS) # $(WARNMORE) -g
+LDFLAGS=$(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) libpng.a -lz -lm
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+include scripts/pnglibconf.mak
+DELETE = $(RM_F)
+DFNFLAGS = $(DEFS) $(CPPFLAGS)
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo libdir=\"$(LIBPATH)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo R_opts=\"-R$(LIBPATH)\"; \
+	echo ccopts=\"-fast -xtarget=ultra\"; \
+	echo ldopts=\"-fast -xtarget=ultra\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	@case "`type ld`" in *ucb*) \
+	echo; \
+	echo '## WARNING:'; \
+	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
+	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
+	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
+	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
+	echo '## at all.  If it is, things are likely to break because of'; \
+	echo '## the libucb dependency that is created.'; \
+	echo; \
+	;; \
+	esac
+	$(LD) -G -L$(ZLIBLIB) -R$(ZLIBLIB) -h $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) $(SUN_CC_FLAGS) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -o pngtestd -L$(DL) -R$(DL) `$(BINPATH)/$(LIBNAME)-config --ldflags` \
+	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) $(SUN_CC_FLAGS) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
+	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
+	libpng-config $(LIBSO) $(LIBSOMAJ)* \
+	libpng.pc
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.64sunu b/extern/libpng/scripts/makefile.64sunu
new file mode 100644
index 0000000000..8880fa9b92
--- /dev/null
+++ b/extern/libpng/scripts/makefile.64sunu
@@ -0,0 +1,244 @@
+# makefile for libpng on Solaris 2.x with cc
+# Contributed by William L. Sebok, based on makefile.linux
+# Copyright (C) 2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1998 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+CC=cc
+AR_RC=ar rc
+MKDIR_P=mkdir -p
+LN_SF=ln -f -s
+RANLIB=echo
+RM_F=/bin/rm -f
+
+SUN_CC_FLAGS=-fast -xtarget=ultra -xarch=v9
+SUN_LD_FLAGS=-fast -xtarget=ultra -xarch=v9
+
+# where make install puts libpng.a, libpng16.so and libpng16/png.h
+prefix=/a
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located
+# Changing these to ../zlib poses a security risk.  If you want
+# to have zlib in an adjacent directory, specify the full path instead of "..".
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+
+ZLIBLIB=/usr/lib
+ZLIBINC=/usr/include
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS= $(SUN_CC_FLAGS) # $(WARNMORE) -g
+LDFLAGS=-L. -R. $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+include scripts/pnglibconf.mak
+DELETE = $(RM_F)
+DFNFLAGS = $(DEFS) $(CPPFLAGS)
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo libdir=\"$(LIBPATH)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo R_opts=\"-R$(LIBPATH)\"; \
+	echo ccopts=\"-fast -xtarget=ultra -xarch=v9\"; \
+	echo ldopts=\"-fast -xtarget=ultra -xarch=v9\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	@case "`type ld`" in *ucb*) \
+	echo; \
+	echo '## WARNING:'; \
+	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
+	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
+	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
+	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
+	echo '## at all.  If it is, things are likely to break because of'; \
+	echo '## the libucb dependency that is created.'; \
+	echo; \
+	;; \
+	esac
+	$(LD) -G -L$(ZLIBLIB) -R$(ZLIBLIB) -h $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) $(SUN_CC_FLAGS) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -o pngtestd -L$(DL) -R$(DL) `$(BINPATH)/$(LIBNAME)-config --ldflags` \
+	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) $(SUN_CC_FLAGS) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
+	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
+	libpng-config $(LIBSO) $(LIBSOMAJ)* \
+	libpng.pc
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.acorn b/extern/libpng/scripts/makefile.acorn
new file mode 100644
index 0000000000..00b8fb5b35
--- /dev/null
+++ b/extern/libpng/scripts/makefile.acorn
@@ -0,0 +1,57 @@
+# Project:   libpng
+
+
+# Toolflags:
+CCflags = -c -depend !Depend -IC:,Zlib: -g -throwback  -DRISCOS  -fnah
+C++flags = -c -depend !Depend -IC: -throwback
+Linkflags = -aif -c++ -o $@
+ObjAsmflags = -throwback -NoCache -depend !Depend
+CMHGflags =
+LibFileflags = -c -l -o $@
+Squeezeflags = -o $@
+
+# Final targets:
+@.libpng-lib:   @.o.png @.o.pngerror @.o.pngrio @.o.pngwio @.o.pngmem \
+	@.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngrtran \
+	@.o.pngrutil @.o.pngtrans @.o.pngwrite @.o.pngwtran @.o.pngwutil
+	LibFile $(LibFileflags) @.o.png @.o.pngerror @.o.pngrio @.o.pngrtran \
+	@.o.pngmem @.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngwio \
+	@.o.pngrutil @.o.pngtrans  @.o.pngwrite @.o.pngwtran @.o.pngwutil
+@.mm-libpng-lib:   @.mm.png @.mm.pngerror @.mm.pngrio @.mm.pngwio @.mm.pngmem \
+	@.mm.pngpread @.mm.pngset @.mm.pngget @.mm.pngread @.mm.pngrtran \
+	@.mm.pngrutil @.mm.pngtrans @.mm.pngwrite @.mm.pngwtran @.mm.pngwutil
+	LibFile $(LibFileflags) @.mm.png @.mm.pngerror @.mm.pngrio \
+	@.mm.pngwio @.mm.pngmem @.mm.pngpread @.mm.pngset @.mm.pngget \
+	@.mm.pngread @.mm.pngrtran @.mm.pngrutil @.mm.pngtrans @.mm.pngwrite \
+	@.mm.pngwtran @.mm.pngwutil
+
+
+# User-editable dependencies:
+# (C) Copyright 1997 Tom Tanner
+Test: @.pngtest
+	<Prefix$Dir>.pngtest
+	@remove <Prefix$Dir>.pngtest
+
+#It would be nice if you could stop "make" listing from here on!
+@.pngtest:   @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib
+	Link $(Linkflags) @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib
+
+.SUFFIXES: .o .mm .c
+
+.c.mm:
+	MemCheck.CC cc $(ccflags) -o $@ LibPng:$<
+.c.o:
+	cc $(ccflags) -o $@ $<
+
+# See scripts.mak.libpngconf for how to generate this:
+@.h.libpngconf: @.scripts.h.libpngconf
+	copy @.scripts.h.libpngconf $@
+
+# Static dependencies:
+@.o.png @.o.pngerror @.o.pngrio @.o.pngwio @.o.pngmem \
+@.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngrtran \
+@.o.pngrutil @.o.pngtrans @.o.pngwrite @.o.pngwtran @.o.pngwutil \
+@.o.pngtest: @.h.libpngconf
+
+
+# Dynamic dependencies:
diff --git a/extern/libpng/scripts/makefile.aix b/extern/libpng/scripts/makefile.aix
new file mode 100644
index 0000000000..5f62d50afb
--- /dev/null
+++ b/extern/libpng/scripts/makefile.aix
@@ -0,0 +1,116 @@
+# makefile for libpng using gcc (generic, static library)
+# Copyright (C) 2002, 2006-2009, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000 Cosmin Truta
+# Copyright (C) 2000 Marc O. Gloor (AIX support added, from makefile.gcc)
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = gcc
+LD = $(CC)
+AR_RC = ar rcs
+MKDIR_P = mkdir -p
+RANLIB = ranlib
+RM_F = rm -f
+LN_SF = ln -f -s
+
+LIBNAME = libpng16
+PNGMAJ = 16
+
+prefix=/usr/local
+INCPATH=$(prefix)/include
+LIBPATH=$(prefix)/lib
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+
+WARNMORE =
+CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS = -W -Wall -O2 # $(WARNMORE) -g
+LDFLAGS = -L. -L$(ZLIBLIB) -lpng16 -lz -lm
+
+# Variables
+OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
+	pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+	pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: $(LIBNAME).a pngtest$(E)
+
+include scripts/pnglibconf.mak
+REMOVE = $(RM_F)
+DFNFLAGS = $(DEFS) $(CPPFLAGS)
+
+$(LIBNAME).a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+test: pngtest$(E)
+	./pngtest$(E)
+
+pngtest$(E): pngtest.o $(LIBNAME).a
+	$(LD) -o $@ pngtest.o $(LDFLAGS)
+
+install: $(LIBNAME).a
+	-@if [ ! -d $(DI)  ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME)  ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DI)/$(LIBNAME)/png.h
+	-@$(RM_F) $(DI)/$(LIBNAME)/pngconf.h
+	-@$(RM_F) $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h
+	-@$(RM_F) $(DI)/pngconf.h
+	-@$(RM_F) $(DI)/pnglibconf.h
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h \
+	$(DI)/$(LIBNAME)/pngconf.h \
+	$(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) -r $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+	-@$(RM_F) $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	cp $(LIBNAME).a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+	(cd $(DI); $(LN_SF) libpng/* .;)
+
+clean:
+	$(RM_F) *.o $(LIBNAME).a pngtest pngout.png pnglibconf.h
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.amiga b/extern/libpng/scripts/makefile.amiga
new file mode 100644
index 0000000000..16a4bd5d33
--- /dev/null
+++ b/extern/libpng/scripts/makefile.amiga
@@ -0,0 +1,58 @@
+# Commodore Amiga Makefile
+# makefile for libpng and SAS C V6.5x compiler
+# Copyright (C) 1995-2000 Wolf Faust
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Location/path of zlib include files
+ZLIB=/zlib
+#compiler
+CC=sc
+#compiler flags
+# WARNING: a bug in V6.51 causes bad code with OPTGO
+#          So use V6.55 or set NOOPTGO!!!!!!!!!
+CFLAGS= NOSTKCHK PARMS=REG OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL\
+	OPTLOOP OPTRDEP=4 OPTDEP=4 OPTCOMP=4 INCLUDEDIR=$(ZLIB) \
+	DEFINE=PNG_INTERNAL
+#linker flags
+LDFLAGS= SD ND BATCH
+#link libs
+LDLIBS= libpng.lib libgz.lib LIB:scm.lib LIB:sc.lib Lib:amiga.lib
+# linker
+LN= slink
+# file deletion command
+RM= delete quiet
+# library (.lib) file creation command
+AR= oml
+# make directory command
+MKDIR= makedir
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+all: libpng.lib pngtest
+
+libpng.lib: $(OBJS)
+-$(RM) libpng.lib
+$(AR) libpng.lib r $(OBJS)
+
+$(OBJS): pngpriv.h png.h pngconf.h pnglibconf.h pnginfo.h pngstruct.h pngdebug.h
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+COPY $(PNGLIBCONF_H_PREBUILT) TO pnglibconf.h
+
+pngtest: pngtest.o libpng.lib
+$(LN) <WITH <
+$(LDFLAGS)
+TO pngtest
+FROM LIB:c.o pngtest.o
+LIB $(LDLIBS)
+<
+
diff --git a/extern/libpng/scripts/makefile.atari b/extern/libpng/scripts/makefile.atari
new file mode 100644
index 0000000000..b5dbd4934a
--- /dev/null
+++ b/extern/libpng/scripts/makefile.atari
@@ -0,0 +1,71 @@
+# makefile for libpng
+# Copyright (C) 2002, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Modified for LC56/ATARI assumes libz.lib is in same dir and uses default
+# rules for library management
+#
+CPPFLAGS = -I..\zlib
+CFLAGS = -O
+LBR = png.lib
+LDFLAGS = -L. -L..\zlib -lpng -lz -lm
+
+# where make install puts libpng.a and png.h
+prefix=/usr/local
+INCPATH=$(prefix)/include
+LIBPATH=$(prefix)/lib
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = $(LBR)(png.o) $(LBR)(pngset.o) $(LBR)(pngget.o) $(LBR)(pngrutil.o)\
+	$(LBR)(pngtrans.o) $(LBR)(pngwutil.o)\
+	$(LBR)(pngread.o) $(LBR)(pngerror.o) $(LBR)(pngwrite.o)\
+	$(LBR)(pngrtran.o) $(LBR)(pngwtran.o)\
+	$(LBR)(pngmem.o) $(LBR)(pngrio.o) $(LBR)(pngwio.o) $(LBR)(pngpread.o)
+
+all: $(LBR) pngtest.ttp
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+$(LBR): $(OBJS)
+
+$(OBJS): pngpriv.h png.h pngconf.h pnglibconf.h pnginfo.h pngstruct.h pngdebug.h
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	cp $(PNGLIBCONF_H_PREBUILT) $@
+
+pngtest.ttp: pngtest.o $(LBR)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o$@ pngtest.o
+
+install: libpng.a
+	-@mkdir $(DESTDIR)$(INCPATH)
+	-@mkdir $(DESTDIR)$(INCPATH)/libpng
+	-@mkdir $(DESTDIR)$(LIBPATH)
+	-@rm -f $(DESTDIR)$(INCPATH)/png.h
+	-@rm -f $(DESTDIR)$(INCPATH)/pngconf.h
+	-@rm -f $(DESTDIR)$(INCPATH)/pnglibconf.h
+	cp png.h $(DESTDIR)$(INCPATH)/libpng
+	cp pngconf.h $(DESTDIR)$(INCPATH)/libpng
+	cp pnglibconf.h $(DESTDIR)$(INCPATH)/libpng
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/png.h
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pngconf.h
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pnglibconf.h
+	(cd $(DESTDIR)$(INCPATH); ln -f -s $(LIBNAME) libpng; \
+	ln -f -s $(LIBNAME)/* .)
diff --git a/extern/libpng/scripts/makefile.bc32 b/extern/libpng/scripts/makefile.bc32
new file mode 100644
index 0000000000..bdbc4cb2f9
--- /dev/null
+++ b/extern/libpng/scripts/makefile.bc32
@@ -0,0 +1,158 @@
+# Makefile for libpng
+# 32-bit Borland C++ (Note: All modules are compiled in C mode)
+# To build the library, do:
+#       "make -fmakefile.bc32"
+#
+# -------------------- 32-bit Borland C++ --------------------
+
+### Absolutely necessary for this makefile to work
+.AUTODEPEND
+
+## Where zlib.h, zconf.h and zlib.lib are
+ZLIB_DIR=..\zlib
+
+## Compiler, linker, librarian and other tools
+CC=bcc32
+LD=bcc32
+LIB=tlib
+CP=copy
+
+# -3 = 386, -4 = 486, -5 = Pentium etc.
+!ifndef TARGET_CPU
+#TARGET_CPU=-6
+!endif
+
+# Use this if you don't want Borland's fancy exception handling
+# (Caution: doesn't work with CBuilderX)
+#NOEHLIB=noeh32.lib
+
+!ifdef DEBUG
+CDEBUG=-v
+LDEBUG=-v
+!else
+CDEBUG=
+LDEBUG=
+!endif
+
+# STACKOFLOW=1
+!ifdef STACKOFLOW
+CDEBUG=$(CDEBUG) -N
+LDEBUG=$(LDEBUG) -N
+!endif
+
+# -O2 optimize for speed
+# -d  merge duplicate strings
+# -k- turn off standard stack frame
+# -w  display all warnings
+CPPFLAGS=-I$(ZLIB_DIR)
+CFLAGS=-O2 -d -k- -w $(TARGET_CPU) $(CDEBUG)
+
+# -M  generate map file
+LDFLAGS=-L$(ZLIB_DIR) -M $(LDEBUG)
+
+# Pre-built configuration
+# See scripts\pnglibconf.mak for more options
+!ifndef PNGLIBCONF_H_PREBUILT
+PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
+!endif
+
+## Variables
+OBJS = \
+	png.obj \
+	pngerror.obj \
+	pngget.obj \
+	pngmem.obj \
+	pngpread.obj \
+	pngread.obj \
+	pngrio.obj \
+	pngrtran.obj \
+	pngrutil.obj \
+	pngset.obj \
+	pngtrans.obj \
+	pngwio.obj \
+	pngwrite.obj \
+	pngwtran.obj \
+	pngwutil.obj
+
+LIBOBJS = \
+	+png.obj \
+	+pngerror.obj \
+	+pngget.obj \
+	+pngmem.obj \
+	+pngpread.obj \
+	+pngread.obj \
+	+pngrio.obj \
+	+pngrtran.obj \
+	+pngrutil.obj \
+	+pngset.obj \
+	+pngtrans.obj \
+	+pngwio.obj \
+	+pngwrite.obj \
+	+pngwtran.obj \
+	+pngwutil.obj
+
+LIBNAME=libpng.lib
+
+## Implicit rules
+# Braces let make "batch" calls to the compiler,
+# 2 calls instead of 12; space is important.
+.c.obj:
+	$(CC) $(CPPFLAGS) $(CFLAGS) -c {$*.c }
+
+.c.exe:
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $*.c \
+	  $(LIBNAME) zlib.lib $(NOEHLIB)
+
+.obj.exe:
+	$(LD) $(LDFLAGS) $*.obj $(LIBNAME) zlib.lib $(NOEHLIB)
+
+## Major targets
+all: libpng pngtest
+
+libpng: $(LIBNAME)
+
+pngtest: pngtest.exe
+
+test: pngtest.exe
+	pngtest
+
+## Minor Targets
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+png.obj: png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.obj: pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.obj: pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.obj: pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.obj: pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.obj: pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.obj: pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.obj: pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.obj: pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.obj: pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.obj: pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.obj: pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.obj: pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.obj: pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.obj: pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtest.obj: pngtest.c png.h pngconf.h pnglibconf.h
+
+$(LIBNAME): $(OBJS)
+	-del $(LIBNAME)
+	$(LIB) $(LIBNAME) @&&|
+$(LIBOBJS), libpng
+|
+
+# Cleanup
+clean:
+	-del pnglibconf.h
+	-del *.obj
+	-del $(LIBNAME)
+	-del pngtest.exe
+	-del *.lst
+	-del *.map
+	-del *.tds
+	-del pngout.png
+
+# End of makefile for libpng
diff --git a/extern/libpng/scripts/makefile.beos b/extern/libpng/scripts/makefile.beos
new file mode 100644
index 0000000000..01346f190a
--- /dev/null
+++ b/extern/libpng/scripts/makefile.beos
@@ -0,0 +1,222 @@
+# makefile for libpng on BeOS x86 ELF with gcc
+# modified from makefile.linux by Sander Stoks
+# Copyright (C) 2002, 2006, 2008, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1999 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+CC=gcc
+AR_RC=ar rc
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+RANLIB=ranlib
+CP=cp
+RM_F=/bin/rm -f
+
+# Where the zlib library and include files are located
+ZLIBLIB=/usr/local/lib
+ZLIBINC=/usr/local/include
+
+ALIGN=
+# For i386:
+# ALIGN=-malign-loops=2 -malign-functions=2
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
+
+# On BeOS, -O1 is actually better than -O3.  This is a known bug but it's
+# still here in R4.5
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-W -Wall -O1 -funroll-loops $(ALIGN) # $(WARNMORE) -g
+# LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng -lz
+LDFLAGS=-L. -Wl,-soname=$(LIBSOMAJ) -L$(ZLIBLIB) -lz
+
+# where make install puts libpng.a, libpng16.so*, and png.h
+prefix=/usr/local
+exec_prefix=$(prefix)
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS)
+
+.SUFFIXES:      .c .o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo libs=\"-lpng16 -lz \"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+	cp $(LIBSO)* /boot/home/config/lib
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(CC) -nostart -Wl,-soname,$(LIBSOMAJ) -o \
+	$(LIBSOMAJ) $(OBJSDLL) $(LDFLAGS)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -L$(ZLIBLIB) -L. -lz -lpng16 -o pngtest pngtest.o
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) $(CFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) -Wl,-rpath $(ZLIBLIB):$(DL) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	$(CC) $(CPPFLAGS) $(CFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png libpng-config \
+	$(LIBSO) $(LIBSOMAJ)* pngtesti \
+	pnglibconf.h libpng.pc
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.cegcc b/extern/libpng/scripts/makefile.cegcc
new file mode 100644
index 0000000000..6f915c2bf5
--- /dev/null
+++ b/extern/libpng/scripts/makefile.cegcc
@@ -0,0 +1,116 @@
+# Makefile for creating Windows CE release archives, with the
+# mingw32ce compiler.
+
+# Last updated: 22-Jul-2008
+
+# Copyright (C) 2008 Vincent Torri
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# To get some help, type
+#
+# make help
+#
+# To create the archives
+#
+# make
+#
+# To remove everything, type:
+#
+# make clean
+
+VERMAJ = 1
+VERMIN = 6
+VERMIC = 37
+VER = $(VERMAJ).$(VERMIN).$(VERMIC)
+NAME = libpng
+PACKAGE = $(NAME)-$(VER)
+
+BIN = libpng16-0.dll
+LIB = libpng16.a libpng16.dll.a libpng.a libpng.dll.a
+INCLUDE = png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+PC = libpng16.pc libpng.pc
+
+MANIFESTVERBIN = "Libpng-$(VER): Binary files"
+MANIFESTVERDEV = "Libpng-$(VER): Developer files"
+MANIFESTVERDESC = "Libpng: the official PNG reference library"
+
+all: $(NAME)
+
+$(NAME): remove-old copy-src compilation copy manifest archive
+	@echo " * Removal of the directories"
+	@rm -rf $(PACKAGE)/ $(PACKAGE)-bin/ $(PACKAGE)-dev/
+
+remove-old:
+	@echo " * Removal of the old files"
+	@rm -rf $(PACKAGE)-bin*
+	@rm -rf $(PACKAGE)-dev*
+
+copy-src:
+	@echo " * Copy of source files"
+	@cp -R ../src/$(PACKAGE) .
+	@echo " * Creation of directories and files"
+	@mkdir -p $(PACKAGE)-bin/bin
+	@mkdir -p $(PACKAGE)-bin/manifest
+	@mkdir -p $(PACKAGE)-dev/lib/pkgconfig
+	@mkdir -p $(PACKAGE)-dev/include/$(NAME)$(VERMAJ)$(VERMIN)
+	@mkdir -p $(PACKAGE)-dev/manifest
+	@touch $(PACKAGE)-bin/manifest/$(PACKAGE)-bin.mft
+	@touch $(PACKAGE)-bin/manifest/$(PACKAGE)-bin.ver
+	@touch $(PACKAGE)-dev/manifest/$(PACKAGE)-dev.mft
+	@touch $(PACKAGE)-dev/manifest/$(PACKAGE)-dev.ver
+
+compilation:
+	@echo " * Compilation of $(PACKAGE)"
+	cd $(PACKAGE) && CPPFLAGS="$(CPPFLAGS) -DPNG_CONSOLE_IO_SUPPORTED -D_WIN32_WCE=0x0420" \
+		CFLAGS="$(CFLAGS) -mms-bitfields -O3 -pipe -fomit-frame-pointer" \
+		LDFLAGS="$(LDFLAGS) -Wl,--enable-auto-import -Wl,-s" \
+		./configure --prefix=/opt/wince --host=arm-mingw32ce && make
+
+copy:
+	@echo " * Copy of binary and development files"
+	@for i in $(BIN); do \
+	  cp $(PACKAGE)/.libs/$$i $(PACKAGE)-bin/bin; \
+	done
+	@for i in $(LIB); do \
+	  cp $(PACKAGE)/.libs/$$i $(PACKAGE)-dev/lib; \
+	done
+	@for i in $(INCLUDE); do \
+	  cp $(PACKAGE)/$$i $(PACKAGE)-dev/include/$(NAME)$(VERMAJ)$(VERMIN); \
+	done
+	@for i in $(PC); do \
+	  cp $(PACKAGE)/$$i $(PACKAGE)-dev/lib/pkgconfig; \
+	done
+
+manifest:
+	@echo " * Creation of the manifest"
+	@cd $(PACKAGE)-bin && find * >> manifest/$(PACKAGE)-bin.mft
+	@cd $(PACKAGE)-bin && \
+	  echo $(MANIFESTVERBIN) >> manifest/$(PACKAGE)-bin.ver && \
+	  echo $(MANIFESTVERDESC) >> manifest/$(PACKAGE)-bin.ver
+	@cd $(PACKAGE)-dev && find * >> manifest/$(PACKAGE)-dev.mft
+	@cd $(PACKAGE)-dev && \
+	  echo $(MANIFESTVERDEV) >> manifest/$(PACKAGE)-dev.ver && \
+	  echo $(MANIFESTVERDESC) >> manifest/$(PACKAGE)-dev.ver
+
+archive:
+	@echo " * Creation of the archives"
+	@tar cf $(PACKAGE)-bin.tar $(PACKAGE)-bin
+	@bzip2 -9 $(PACKAGE)-bin.tar
+	@tar cf $(PACKAGE)-dev.tar $(PACKAGE)-dev
+	@bzip2 -9 $(PACKAGE)-dev.tar
+
+clean:
+	@echo " * Cleaning"
+	@rm -rf $(PACKAGE)*
+
+help:
+	@echo
+	@echo "To create the archives, type:"
+	@echo " make"
+	@echo
+	@echo "To remove everything, type:"
+	@echo " make clean"
+	@echo
diff --git a/extern/libpng/scripts/makefile.clang b/extern/libpng/scripts/makefile.clang
new file mode 100644
index 0000000000..fcaefae9b5
--- /dev/null
+++ b/extern/libpng/scripts/makefile.clang
@@ -0,0 +1,87 @@
+# makefile for libpng using clang (generic, static library)
+# Copyright (C) 2008, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000, 2014, 2019 Cosmin Truta
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = clang
+LD = $(CC)
+AR_RC = ar rcs
+RANLIB = ranlib
+CP = cp
+RM_F = rm -f
+
+WARNMORE = -Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS = -W -Wall -O2 # $(WARNMORE) -g
+LDFLAGS = -L$(ZLIBLIB)
+LIBS = -lz -lm
+
+# File extensions
+EXEEXT =
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# Variables
+OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
+	pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+	pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+all: static
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+static: libpng.a pngtest$(EXEEXT)
+
+shared:
+	@echo This is a generic makefile that cannot create shared libraries.
+	@echo Please use a configuration that is specific to your platform.
+	@false
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+test: pngtest$(EXEEXT)
+	./pngtest$(EXEEXT)
+
+pngtest$(EXEEXT): pngtest.o libpng.a
+	$(LD) $(LDFLAGS) -o $@ pngtest.o libpng.a $(LIBS)
+
+clean:
+	$(RM_F) *.o libpng.a pngtest$(EXEEXT) pngout.png pnglibconf.h
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.clang-asan b/extern/libpng/scripts/makefile.clang-asan
new file mode 100644
index 0000000000..0cab52fd09
--- /dev/null
+++ b/extern/libpng/scripts/makefile.clang-asan
@@ -0,0 +1,87 @@
+# makefile for libpng using clang + address sanitizer (generic, static library)
+# Copyright (C) 2008, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000, 2014, 2019 Cosmin Truta
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = clang
+LD = $(CC)
+AR_RC = ar rcs
+RANLIB = ranlib
+CP = cp
+RM_F = rm -f
+
+WARNMORE = -Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS = -W -Wall -O0 -g -fsanitize=address
+LDFLAGS = -L$(ZLIBLIB) -g -fsanitize=address
+LIBS = -lz -lm
+
+# File extensions
+EXEEXT =
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# Variables
+OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
+	pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+	pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+all: static
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+static: libpng.a pngtest$(EXEEXT)
+
+shared:
+	@echo This is a generic makefile that cannot create shared libraries.
+	@echo Please use a configuration that is specific to your platform.
+	@false
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+test: pngtest$(EXEEXT)
+	./pngtest$(EXEEXT)
+
+pngtest$(EXEEXT): pngtest.o libpng.a
+	$(LD) $(LDFLAGS) -o $@ pngtest.o libpng.a $(LIBS)
+
+clean:
+	$(RM_F) *.o libpng.a pngtest$(EXEEXT) pngout.png pnglibconf.h
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.darwin b/extern/libpng/scripts/makefile.darwin
new file mode 100644
index 0000000000..33c27cc1f0
--- /dev/null
+++ b/extern/libpng/scripts/makefile.darwin
@@ -0,0 +1,225 @@
+# makefile for libpng on Darwin / Mac OS X
+# Copyright (C) 2002, 2004, 2006, 2008, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 2001 Christoph Pfisterer
+# derived from makefile.linux:
+#  Copyright (C) 1998, 1999 Greg Roelofs
+#  Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# where "make install" puts libpng.a, libpng16.dylib, png.h, pngconf.h,
+# and pnglibconf.h
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located
+ZLIBLIB=/usr/lib
+ZLIBINC=/usr/include
+
+# Library name:
+LIBNAME = libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).dylib
+LIBSOMAJ=$(LIBNAME).$(PNGMAJ).dylib
+LIBSOREL=$(LIBNAME).$(PNGMAJ).$(RELEASE).dylib
+OLDSO=libpng.dylib
+
+# Utilities:
+CC=cc
+AR_RC=ar rc
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+RANLIB=ranlib
+CP=cp
+RM_F=/bin/rm -f
+
+CPPFLAGS=-I$(ZLIBINC)
+# CFLAGS=-W -Wall -O3 -funroll-loops
+CFLAGS=-W -Wall -O -funroll-loops
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fno-common -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(CC) -dynamiclib \
+	 -install_name $(LIBPATH)/$(LIBSOMAJ) \
+	 -current_version 16 -compatibility_version 16 \
+	 -o $(LIBSOMAJ) \
+	 $(OBJSDLL) -L$(ZLIBLIB) -lz
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	$(RANLIB) $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOMAJ)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)
+	chmod 755 $(DL)/$(LIBSOMAJ)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	$(CC) $(CPPFLAGS) $(CFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png libpng-config \
+	libpng.pc $(LIBNAME).*dylib pngtesti pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.dec b/extern/libpng/scripts/makefile.dec
new file mode 100644
index 0000000000..8566a0297b
--- /dev/null
+++ b/extern/libpng/scripts/makefile.dec
@@ -0,0 +1,210 @@
+# makefile for libpng on DEC Alpha Unix
+# Copyright (C) 2000-2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+PNGMAJ = 16
+LIBNAME = libpng16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+AR_RC=ar rc
+CC=cc
+MKDIR_P=mkdir
+LN_SF=ln -f -s
+RANLIB=ranlib
+CP=cp
+RM_F=/bin/rm -f
+
+# where make install puts libpng.a and png.h
+prefix=/usr/local
+exec_prefix=$(prefix)
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-std -w1 -O # -g
+LDFLAGS=-L$(ZLIBLIB) -rpath $(ZLIBLIB) libpng.a -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: $(LIBSO) libpng.a pngtest libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@  $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo ccopts=\"-std\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJS)
+	$(CC) -shared -o $@ $(OBJS) -L$(ZLIBLIB) \
+	-soname $(LIBSOMAJ)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@/bin/rm -f $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@/bin/rm -f $(DI)/libpng
+	(cd $(DI); $(LN_SF)(LIBNAME) libpng; $(LN_SF)(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@/bin/rm -f $(DL)/libpng.a
+	(cd $(DL); $(LN_SF)(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@/bin/rm -f $(DM)/man3/libpng.3
+	-@/bin/rm -f $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@/bin/rm -f $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@/bin/rm -f $(DB)/libpng-config
+	-@/bin/rm -f $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF)(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -w1 -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB)  -R$(ZLIBLIB) -R$(DL) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) -w1 $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) -R$(ZLIBLIB) \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
+	libpng-config $(LIBSO) $(LIBSOMAJ)* \
+	libpng.pc pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.dj2 b/extern/libpng/scripts/makefile.dj2
new file mode 100644
index 0000000000..e59c432b44
--- /dev/null
+++ b/extern/libpng/scripts/makefile.dj2
@@ -0,0 +1,72 @@
+# DJGPP (DOS gcc) makefile for libpng
+# Copyright (C) 2002, 2006, 2009-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# where make install will put libpng.a and png.h
+#prefix=/usr/local
+prefix=.
+INCPATH=$(prefix)/include
+LIBPATH=$(prefix)/lib
+
+CC=gcc
+CPPFLAGS=-I../zlib -DPNG_NO_SNPRINTF
+CFLAGS=-O
+LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
+
+RANLIB=ranlib
+
+CP=cp
+RM_F=rm -f
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o pngwtran.o \
+	pngmem.o pngerror.o pngpread.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	ar rc $@  $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+	coff2exe pngtest
+
+test: pngtest
+	./pngtest
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.freebsd b/extern/libpng/scripts/makefile.freebsd
new file mode 100644
index 0000000000..5fec61e351
--- /dev/null
+++ b/extern/libpng/scripts/makefile.freebsd
@@ -0,0 +1,69 @@
+# makefile for libpng under FreeBSD
+# Copyright (C) 2014 Glenn Randers-Pehrson and Andrey A. Chernov
+# Copyright (C) 2002, 2007, 2009 Glenn Randers-Pehrson and Andrey A. Chernov
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+PREFIX?=        /usr/local
+SHLIB_VER?=     16
+
+LIB=		png
+SHLIB_MAJOR=	${SHLIB_VER}
+SHLIB_MINOR=	0
+NO_PROFILE=	YES
+NO_OBJ=		YES
+
+# where make install puts libpng.a and png.h
+DESTDIR=	${PREFIX}
+LIBDIR=		/lib
+INCS=		png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+INCSDIR=	/include/libpng
+INCDIR=		${INCSDIR}		# for 4.x bsd.lib.mk
+MAN=		libpng.3 libpngpf.3 png.5
+MANDIR=		/man/man
+SYMLINKS=       libpng/png.h ${INCSDIR}/../png.h \
+		libpng/pngconf.h ${INCSDIR}/../pngconf.h \
+		libpng/pnglibconf.h ${INCSDIR}/../pnglibconf.h
+
+# where make install finds libz.a and zlib.h
+ZLIBLIB=	/usr/lib
+ZLIBINC=	/usr/include
+
+LDADD+=		-lm -lz
+#LDADD+=	-lm -lz -lssp_nonshared   # for OSVERSION < 800000 ?
+
+DPADD+=		${LIBM} ${LIBZ}
+
+CPPFLAGS+=	-I. -I${ZLIBINC}
+CFLAGS+=	-W -Wall
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt
+
+SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
+	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
+	pngwtran.c pngmem.c pngerror.c pngpread.c
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+pngtest: pngtest.o libpng.a
+	${CC} ${CFLAGS} -L. -static -o pngtest pngtest.o -L${ZLIBLIB} \
+	-lpng ${LDADD}
+
+CLEANFILES= pngtest pngtest.o pngout.png
+
+test: pngtest
+	./pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	cp $(PNGLIBCONF_H_PREBUILT) $@
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+.include <bsd.lib.mk>
diff --git a/extern/libpng/scripts/makefile.gcc b/extern/libpng/scripts/makefile.gcc
new file mode 100644
index 0000000000..a97731367e
--- /dev/null
+++ b/extern/libpng/scripts/makefile.gcc
@@ -0,0 +1,87 @@
+# makefile for libpng using gcc (generic, static library)
+# Copyright (C) 2008, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000, 2014, 2019 Cosmin Truta
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = gcc
+LD = $(CC)
+AR_RC = ar rcs
+RANLIB = ranlib
+CP = cp
+RM_F = rm -f
+
+WARNMORE = -Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS = -W -Wall -O2 # $(WARNMORE) -g
+LDFLAGS = -L$(ZLIBLIB)
+LIBS = -lz -lm
+
+# File extensions
+EXEEXT =
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# Variables
+OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
+	pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+	pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+all: static
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+static: libpng.a pngtest$(EXEEXT)
+
+shared:
+	@echo This is a generic makefile that cannot create shared libraries.
+	@echo Please use a configuration that is specific to your platform.
+	@false
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+test: pngtest$(EXEEXT)
+	./pngtest$(EXEEXT)
+
+pngtest$(EXEEXT): pngtest.o libpng.a
+	$(LD) $(LDFLAGS) -o $@ pngtest.o libpng.a $(LIBS)
+
+clean:
+	$(RM_F) *.o libpng.a pngtest$(EXEEXT) pngout.png pnglibconf.h
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.gcc-asan b/extern/libpng/scripts/makefile.gcc-asan
new file mode 100644
index 0000000000..aae55d6380
--- /dev/null
+++ b/extern/libpng/scripts/makefile.gcc-asan
@@ -0,0 +1,87 @@
+# makefile for libpng using gcc + address sanitizer (generic, static library)
+# Copyright (C) 2008, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000, 2014, 2019 Cosmin Truta
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = gcc
+LD = $(CC)
+AR_RC = ar rcs
+RANLIB = ranlib
+CP = cp
+RM_F = rm -f
+
+WARNMORE = -Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS = -W -Wall -O0 -g -fsanitize=address
+LDFLAGS = -L$(ZLIBLIB) -g -fsanitize=address
+LIBS = -lz -lm
+
+# File extensions
+EXEEXT =
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# Variables
+OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
+	pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+	pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+all: static
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+static: libpng.a pngtest$(EXEEXT)
+
+shared:
+	@echo This is a generic makefile that cannot create shared libraries.
+	@echo Please use a configuration that is specific to your platform.
+	@false
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+test: pngtest$(EXEEXT)
+	./pngtest$(EXEEXT)
+
+pngtest$(EXEEXT): pngtest.o libpng.a
+	$(LD) $(LDFLAGS) -o $@ pngtest.o libpng.a $(LIBS)
+
+clean:
+	$(RM_F) *.o libpng.a pngtest$(EXEEXT) pngout.png pnglibconf.h
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.hp64 b/extern/libpng/scripts/makefile.hp64
new file mode 100644
index 0000000000..4421e787d4
--- /dev/null
+++ b/extern/libpng/scripts/makefile.hp64
@@ -0,0 +1,231 @@
+# makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
+# Copyright (C) 1999-2002, 2006, 2009, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42
+# Contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Where the zlib library and include files are located
+ZLIBLIB=/opt/zlib/lib
+ZLIBINC=/opt/zlib/include
+
+# Note that if you plan to build a libpng shared library, zlib must also
+# be a shared library, which zlib's configure does not do.  After running
+# zlib's configure, edit the appropriate lines of makefile to read:
+#   CFLAGS=-O1 -DHAVE_UNISTD -DUSE_MAP -fPIC \
+#   LDSHARED=ld -b
+#   SHAREDLIB=libz.sl
+
+# Library name:
+LIBNAME = libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).sl
+LIBSOMAJ=$(LIBNAME).sl.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.sl
+
+# Utilities:
+AR_RC=ar rc
+CC=cc
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+RANLIB=ranlib
+CP=cp
+RM_F=/bin/rm -f
+
+CPPFLAGS=-I$(ZLIBINC) \
+        -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -DHAVE_UNISTD_H -DUSE_MMAP
+CFLAGS=-O -Ae -Wl,+vnocompatwarnings +DD64 +Z
+# Caution: be sure you have built zlib with the same CFLAGS.
+CCFLAGS=-O -Ae -Wl,+vnocompatwarnings +DD64 +Z
+
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
+
+# where make install puts libpng.a, libpng16.sl, and png.h
+prefix=/opt/libpng
+exec_prefix=$(prefix)
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:	.c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) +z -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo ccopts=\"-O -Ae -Wl,+vnocompatwarnings +DD64 +Z\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(LD) -b +s \
+	+h $(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) $(CCFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) $(CPPFLAGS) $(CCFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
+	libpng-config $(LIBSO) $(LIBSOMAJ)* \
+	libpng.pc pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.hpgcc b/extern/libpng/scripts/makefile.hpgcc
new file mode 100644
index 0000000000..efef1f3fbb
--- /dev/null
+++ b/extern/libpng/scripts/makefile.hpgcc
@@ -0,0 +1,234 @@
+# makefile for libpng on HP-UX using GCC with the HP ANSI/C linker.
+# Copyright (C) 2002, 2006-2008, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 2001, Laurent faillie
+# Copyright (C) 1998, 1999 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME = libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).sl
+LIBSOMAJ=$(LIBNAME).sl.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.sl
+
+# Utilities:
+CC=gcc
+LD=ld
+AR_RC=ar rc
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+RANLIB=ranlib
+CP=cp
+RM_F=/bin/rm -f
+
+# where "make install" puts libpng.a, $(OLDSO)*, png.h, pngconf.h
+# and pnglibconf.h
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located
+ZLIBLIB=/opt/zlib/lib
+ZLIBINC=/opt/zlib/include
+
+# Note that if you plan to build a libpng shared library, zlib must also
+# be a shared library, which zlib's configure does not do.  After running
+# zlib's configure, edit the appropriate lines of makefile to read:
+#   CFLAGS=-O1 -DHAVE_UNISTD -DUSE_MAP -fPIC \
+#   LDSHARED=ld -b
+#   SHAREDLIB=libz.sl
+
+ALIGN=
+# for i386:
+#ALIGN=-malign-loops=2 -malign-functions=2
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
+
+# for pgcc version 2.95.1, -O3 is buggy; don't use it.
+
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-W -Wall -O3 -funroll-loops $(ALIGN) # $(WARNMORE) -g
+#LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng16 -lz -lm
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz -lm
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(LD) -b +s \
+	+h $(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) -Wl,-rpath,$(DL) -Wl,-rpath,$(ZLIBLIB) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
+	libpng-config $(LIBSO) $(LIBSOMAJ)* \
+	libpng.pc pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.hpux b/extern/libpng/scripts/makefile.hpux
new file mode 100644
index 0000000000..27b312a383
--- /dev/null
+++ b/extern/libpng/scripts/makefile.hpux
@@ -0,0 +1,229 @@
+# makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
+# Copyright (C) 1999-2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42
+# Contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Where the zlib library and include files are located
+ZLIBLIB=/opt/zlib/lib
+ZLIBINC=/opt/zlib/include
+
+# Note that if you plan to build a libpng shared library, zlib must also
+# be a shared library, which zlib's configure does not do.  After running
+# zlib's configure, edit the appropriate lines of makefile to read:
+#   CPPFLAGS=-DHAVE_UNISTD -DUSE_MAP
+#   CFLAGS=-O1 -fPIC
+#   LDSHARED=ld -b
+#   SHAREDLIB=libz.sl
+
+# Library name:
+LIBNAME = libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).sl
+LIBSOMAJ=$(LIBNAME).sl.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.sl
+
+# Utilities:
+AR_RC=ar rc
+CC=cc
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+RANLIB=ranlib
+RM_F=/bin/rm -f
+
+# where make install puts libpng.a, libpng16.sl, and png.h
+prefix=/opt/libpng
+exec_prefix=$(prefix)
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+CPPFLAGS=-I$(ZLIBINC)
+CFLAGS=-O -Ae +DA1.1 +DS2.0
+# Caution: be sure you have built zlib with the same CFLAGS.
+CCFLAGS=-O -Ae +DA1.1 +DS2.0
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:	.c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) +z -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo ccopts=\"-O -Ae +DA1.1 +DS2.0\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(LD) -b +s \
+	+h $(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) $(CCFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) $(CPPFLAGS) $(CCFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
+	libpng-config $(LIBSO) $(LIBSOMAJ)* \
+	libpng.pc pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.ibmc b/extern/libpng/scripts/makefile.ibmc
new file mode 100644
index 0000000000..89b11966b0
--- /dev/null
+++ b/extern/libpng/scripts/makefile.ibmc
@@ -0,0 +1,90 @@
+# Makefile for libpng (static)
+# IBM C version 3.x for Win32 and OS/2
+# Copyright (C) 2006, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000 Cosmin Truta
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Notes:
+#   Derived from makefile.std
+#   All modules are compiled in C mode
+#   Tested under Win32, expected to work under OS/2
+#   Can be easily adapted for IBM VisualAge/C++ for AIX
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = icc
+LD = ilink
+AR = ilib
+CP = copy
+RM = del
+
+CPPFLAGS = -I$(ZLIBINC)
+CFLAGS = -Mc -O2 -W3
+LDFLAGS =
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# File extensions
+O=.obj
+A=.lib
+E=.exe
+
+# Variables
+OBJS = png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O) \
+	pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O) \
+	pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
+
+LIBS = libpng$(A) $(ZLIBLIB)/zlib$(A)
+
+# Targets
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+all: libpng$(A) pngtest$(E)
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng$(A): $(OBJS)
+	$(AR) -out:$@ $(OBJS)
+
+test: pngtest$(E)
+	pngtest$(E)
+
+pngtest: pngtest$(E)
+
+pngtest$(E): pngtest$(O) libpng$(A)
+	$(LD) $(LDFLAGS) pngtest$(O) $(LIBS)
+
+clean:
+	$(RM) *$(O)
+	$(RM) libpng$(A)
+	$(RM) pnglibconf.h
+	$(RM) pngtest$(E)
+	$(RM) pngout.png
+
+png$(O):      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread$(O):  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest$(O):  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.intel b/extern/libpng/scripts/makefile.intel
new file mode 100644
index 0000000000..418726159d
--- /dev/null
+++ b/extern/libpng/scripts/makefile.intel
@@ -0,0 +1,115 @@
+# Makefile for libpng
+# Microsoft Visual C++ with Intel C/C++ Compiler 4.0 and later
+
+# Copyright (C) 2006, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000, Pawel Mrochen, based on makefile.msc which is
+# copyright 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# To use, do "nmake /f scripts\makefile.intel"
+#
+# ------------------- Intel C/C++ Compiler 4.0 and later -------------------
+
+# Where the zlib library and include files are located
+ZLIBLIB=..\zlib
+ZLIBINC=..\zlib
+
+# Target CPU
+CPU=6		# Pentium II
+#CPU=5		# Pentium
+
+# Calling convention
+CALLING=r	# __fastcall
+#CALLING=z	# __stdcall
+#CALLING=d	# __cdecl
+
+# Uncomment next to put error messages in a file
+#ERRFILE=>>pngerrs
+
+# --------------------------------------------------------------------------
+
+CC=icl -c
+CPPFLAGS=-I$(ZLIBINC)
+CFLAGS=-O2 -G$(CPU)$(CALLING) -Qip -Qunroll4 -nologo
+LD=link
+LDFLAGS=/SUBSYSTEM:CONSOLE /NOLOGO
+CP=cp
+
+# Pre-built configuration
+# See scripts\pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
+
+O=.obj
+
+OBJS=png$(O) pngset$(O) pngget$(O) pngrutil$(O) pngtrans$(O) pngwutil$(O) \
+pngmem$(O) pngpread$(O) pngread$(O) pngerror$(O) pngwrite$(O) \
+pngrtran$(O) pngwtran$(O) pngrio$(O) pngwio$(O)
+
+all: test
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngget$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngmem$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+libpng.lib: $(OBJS)
+	if exist libpng.lib del libpng.lib
+	lib /NOLOGO /OUT:libpng.lib $(OBJS)
+
+pngtest.exe: pngtest.obj libpng.lib
+	$(LD) $(LDFLAGS) /OUT:pngtest.exe pngtest.obj libpng.lib $(ZLIBLIB)\zlib.lib
+
+pngtest$(O): png.h pngconf.h pnglibconf.h
+	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+test: pngtest.exe
+	pngtest.exe
+
+
+# End of makefile for libpng
diff --git a/extern/libpng/scripts/makefile.linux b/extern/libpng/scripts/makefile.linux
new file mode 100644
index 0000000000..f2d8beae2a
--- /dev/null
+++ b/extern/libpng/scripts/makefile.linux
@@ -0,0 +1,246 @@
+# makefile for libpng.a and libpng16.so on Linux ELF with gcc
+# Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2014 Greg Roelofs and
+# Glenn Randers-Pehrson
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME = libpng16
+PNGMAJ = 16
+RELEASE = 37
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+AR_RC=ar rc
+CC=gcc
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+RANLIB=ranlib
+CP=cp
+RM_F=/bin/rm -f
+
+# where "make install" puts libpng16.a, libpng16.so*,
+# libpng16/png.h, libpng16/pngconf.h, and libpng16/pnglibconf.h
+# Prefix must be a full pathname.
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located.
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+ALIGN=
+# for i386:
+#ALIGN=-malign-loops=2 -malign-functions=2
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
+
+# for pgcc version 2.95.1, -O3 is buggy; don't use it.
+
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-W -Wall -O3 -funroll-loops $(ALIGN) # $(WARNMORE) -g
+
+LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng16 -lz -lm
+LDFLAGS_A=-L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) libpng.a -lz -lm
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS =  png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest pngtest-static libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo R_opts=\"-Wl,-rpath,$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+pngtest-static: pngtest.o libpng.a
+	$(CC) -o pngtest-static $(CFLAGS) pngtest.o $(LDFLAGS_A)
+
+test: pngtest pngtest-static
+	@echo ""
+	@echo "   Running pngtest dynamically linked with $(LIBSO):"
+	@echo ""
+	./pngtest
+	@echo ""
+	@echo "   Running pngtest statically linked with libpng.a:"
+	@echo ""
+	./pngtest-static
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) -Wl, -rpath,$(DL) -Wl,-rpath,$(ZLIBLIB) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	$(CC) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png libpng-config \
+	$(LIBSO) $(LIBSOMAJ)* pngtest-static pngtesti \
+	libpng.pc pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.linux-opt b/extern/libpng/scripts/makefile.linux-opt
new file mode 100644
index 0000000000..327151f0e3
--- /dev/null
+++ b/extern/libpng/scripts/makefile.linux-opt
@@ -0,0 +1,265 @@
+# makefile for libpng.a and libpng16.so on Linux ELF with gcc
+# Copyright (C) 1998,1999,2002,2006,2008,2010-2014,2017 Greg Roelofs and
+# Glenn Randers-Pehrson
+# Copyright (C) 1996,1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME = libpng16
+PNGMAJ = 16
+RELEASE = 37
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+AR_RC=ar rc
+CC=gcc
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+RANLIB=ranlib
+CP=cp
+RM_F=/bin/rm -f
+
+# where "make install" puts libpng16.a, libpng16.so*,
+# libpng16/png.h, libpng16/pngconf.h, and libpng16/pnglibconf.h
+# Prefix must be a full pathname.
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located.
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+ALIGN=
+# for i386:
+#ALIGN=-malign-loops=2 -malign-functions=2
+
+#WARNMORE=-Wwrite-strings -Wpointer-arith \
+#	-Wmissing-declarations -Wtraditional -Wcast-align \
+#	-Wstrict-prototypes -Wmissing-prototypes
+
+# for pgcc version 2.95.1, -O3 is buggy; don't use it.
+
+CPPFLAGS=-I$(ZLIBINC)
+CPPFLAGS += -DPNG_ARM_NEON
+CPPFLAGS += -DPNG_MIPS_MSA
+CPPFLAGS += -DPNG_INTEL_SSE
+CPPFLAGS += -DPNG_POWERPC_VSX
+CPPFLAGS+=-ansi -pedantic -Wextra -Wall -Wshadow -Wno-sign-conversion
+CPPFLAGS+=-W -Wall -Wconversion $(ALIGN)
+# CPPFLAGS+=$(WARNMORE)
+CFLAGS= -O3 -funroll-loops
+
+LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng16 -lz -lm
+LDFLAGS_A=-L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) libpng.a -lz -lm
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS =  png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o \
+	arm/arm_init.o arm/filter_neon_intrinsics.o \
+	mips/mips_init.o mips/filter_msa_intrinsics.o \
+	intel/intel_init.o intel/filter_sse2_intrinsics.o\
+	powerpc/powerpc_init.o powerpc/filter_vsx_intrinsics.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest pngtest-static libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo R_opts=\"-Wl,-rpath,$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+pngtest-static: pngtest.o libpng.a
+	$(CC) -o pngtest-static $(CFLAGS) pngtest.o $(LDFLAGS_A)
+
+test: pngtest pngtest-static
+	@echo ""
+	@echo "   Running pngtest dynamically linked with $(LIBSO):"
+	@echo ""
+	./pngtest
+	@echo ""
+	@echo "   Running pngtest statically linked with libpng.a:"
+	@echo ""
+	./pngtest-static
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) -Wl, -rpath,$(DL) -Wl,-rpath,$(ZLIBLIB) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	$(CC) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png libpng-config \
+	$(LIBSO) $(LIBSOMAJ)* pngtest-static pngtesti \
+	libpng.pc pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+arm/arm_init.o arm/arm_init.o: pngpriv.h
+arm/filter_neon_intrinsics.o arm/filter_neon_intrinsics.pic.o: pngpriv.h
+mips/mips_init.o mips/mips_init.pic.o: pngpriv.h
+mips/filter_msa_intrinsics.o mips/filter_msa_intrinsics.pic.:  pngpriv.h
+intel/intel_init.o intel/intel_init.pic.:  pngpriv.h
+intel/filter_sse2_intrinsics.o intel/filter_sse2_intrinsics.pic.:  pngpriv.h
+powerpc/powerpc_init.o powerpc/powerpc_init.pic.:  pngpriv.h
+powerpc/filter_vsx_intrinsics.o powerpc/filter_vsx_intrinsics.pic.:  pngpriv.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.mips b/extern/libpng/scripts/makefile.mips
new file mode 100644
index 0000000000..0357ae81c1
--- /dev/null
+++ b/extern/libpng/scripts/makefile.mips
@@ -0,0 +1,103 @@
+# makefile for libpng
+# Copyright (C) 1998-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# where make install puts libpng.a and png.h
+prefix=/usr/local
+INCPATH=$(prefix)/include
+LIBPATH=$(prefix)/lib
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+CC=cc
+CPPFLAGS=-I../zlib -DSYSV -Dmips
+CFLAGS=-O -systype sysv -w
+#CFLAGS=-O
+LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
+
+#RANLIB=ranlib
+RANLIB=echo
+
+CP=cp
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	ar rc $@  $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install: libpng.a
+	-@mkdir $(DESTDIR)$(INCPATH)
+	-@mkdir $(DESTDIR)$(INCPATH)/libpng
+	-@mkdir $(DESTDIR)$(LIBPATH)
+	-@rm -f $(DESTDIR)$(INCPATH)/png.h
+	-@rm -f $(DESTDIR)$(INCPATH)/pngconf.h
+	-@rm -f $(DESTDIR)$(INCPATH)/pnglibconf.h
+	cp png.h $(DESTDIR)$(INCPATH)/libpng
+	cp pngconf.h $(DESTDIR)$(INCPATH)/libpng
+	cp pnglibconf.h $(DESTDIR)$(INCPATH)/libpng
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/png.h
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pngconf.h
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pnglibconf.h
+	(cd $(DESTDIR)$(INCPATH); ln -f -s libpng/* .)
+	cp libpng.a $(DESTDIR)$(LIBPATH)
+	chmod 644 $(DESTDIR)$(LIBPATH)/libpng.a
+
+clean:
+	rm -f *.o libpng.a pngtest pngout.png pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.msys b/extern/libpng/scripts/makefile.msys
new file mode 100644
index 0000000000..6b9daf836b
--- /dev/null
+++ b/extern/libpng/scripts/makefile.msys
@@ -0,0 +1,202 @@
+# makefile for libpng using MSYS/gcc (shared, static library)
+# Copyright (C) 2019 Cosmin Truta
+# Copyright (C) 2012 Glenn Randers-Pehrson and Christopher M. Wheeler
+#
+# Portions taken from makefile.linux and makefile.gcc:
+# Copyright (C) 2000 Cosmin Truta
+# Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2014 Greg Roelofs and
+# Glenn Randers-Pehrson
+# Copyright (C) 1996, 1997 Andreas Dilger
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+# # # # # # # # # # # # # # # # #
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Library name:
+LIBNAME = libpng16
+PNGMAJ = 16
+RELEASE = 37
+
+# Shared library names:
+LIBSO=$(LIBNAME).dll
+LIBSOMAJ=$(LIBNAME).dll.$(PNGMAJ)
+LIBSOREL=$(PNGMAJ).$(RELEASE)
+OLDSO=libpng.dll
+
+# Where the zlib library and include files are located.
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+ZLIBLIB=/usr/local/lib
+ZLIBINC=/usr/local/include
+
+# Compiler, linker, lib and other tools
+CC = gcc
+LD = $(CC)
+AR_RC = ar rcs
+RANLIB = ranlib
+CP = cp
+RM_F = rm -rf
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+
+#ARCH = -march=pentium3
+#ARCH = -march=i686
+ARCH =
+CPPFLAGS = # -DPNG_DEBUG=5
+CFLAGS = -W -Wall -O2 $(ARCH) # -g
+LDFLAGS =
+LIBS = -lz -lm
+
+# File extensions
+EXEEXT=.exe
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# Variables
+OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
+	pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+	pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+all: static shared
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+static: libpng.a pngtest$(EXEEXT)
+
+shared: $(LIBSOMAJ)
+	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) -o $(LIBSO)
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ):
+	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) -o $(LIBSOMAJ)
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo R_opts=\"-Wl,-rpath,$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSO) $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+test: pngtest$(EXEEXT)
+	./pngtest$(EXEEXT)
+
+pngtest$(EXEEXT): pngtest.o libpng.a
+	$(LD) $(LDFLAGS) -o $@ pngtest.o libpng.a $(LIBS)
+
+clean:
+	$(RM_F) *.o libpng.a pngtest$(EXEEXT) pngout.png pnglibconf.h $(LIBSO) \
+	$(LIBSOMAJ) libpng-config
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.netbsd b/extern/libpng/scripts/makefile.netbsd
new file mode 100644
index 0000000000..9a6b04629a
--- /dev/null
+++ b/extern/libpng/scripts/makefile.netbsd
@@ -0,0 +1,55 @@
+# makefile for libpng for NetBSD for the standard
+# make obj && make depend && make && make test
+# make includes && make install
+# Copyright (C) 2002 Patrick R.L. Welche
+# Copyright (C) 2007-2009, 2014 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+LOCALBASE?=/usr/local
+LIBDIR=	${LOCALBASE}/lib
+MANDIR= ${LOCALBASE}/man
+INCSDIR=${LOCALBASE}/include
+
+SHLIB_MAJOR=	16
+SHLIB_MINOR=	1.6.37
+
+LIB=	png
+SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
+	pngread.c pngrio.c pngrtran.c pngrutil.c pngset.c pngtrans.c \
+	pngwio.c pngwrite.c pngwtran.c pngwutil.c
+INCS=	png.h pngconf.h pnglibconf.h
+MAN=	libpng.3 libpngpf.3 png.5
+
+CPPFLAGS+=-I${.CURDIR}
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt
+
+# We should be able to do something like this instead of the manual
+# uncommenting, but it core dumps for me at the moment:
+# .if ${MACHINE_ARCH} == "i386"
+#   MKLINT= no
+# .endif
+
+CLEANFILES+=pngtest.o pngtest pnglibconf.h
+
+.c.o:
+	${CC} -c ${CPPFLAGS} ${CFLAGS} -o $@ $<
+
+pnglibconf.h: ${PNGLIBCONF_H_PREBUILT}
+	cp ${PNGLIBCONF_H_PREBUILT} $@
+
+pngtest.o:	pngtest.c
+	${CC} -c ${CPPFLAGS} ${CFLAGS} ${.ALLSRC} -o ${.TARGET}
+
+pngtest:	pngtest.o libpng.a
+	${CC} ${LDFLAGS} ${.ALLSRC} -o ${.TARGET} -lz -lm
+
+test:	pngtest
+	cd ${.CURDIR} && ${.OBJDIR}/pngtest
+
+.include <bsd.lib.mk>
diff --git a/extern/libpng/scripts/makefile.openbsd b/extern/libpng/scripts/makefile.openbsd
new file mode 100644
index 0000000000..ad5ffb3a3e
--- /dev/null
+++ b/extern/libpng/scripts/makefile.openbsd
@@ -0,0 +1,86 @@
+# makefile for libpng
+# Copyright (C) 2007-2009, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+PREFIX?= /usr/local
+LIBDIR=	${PREFIX}/lib
+MANDIR= ${PREFIX}/man/cat
+
+SHLIB_MAJOR=	16
+SHLIB_MINOR=	1.6.37
+
+LIB=	png
+SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
+	pngread.c pngrio.c pngrtran.c pngrutil.c pngset.c pngtrans.c \
+	pngwio.c pngwrite.c pngwtran.c pngwutil.c
+HDRS=	png.h pngconf.h pnglibconf.h
+MAN=	libpng.3 libpngpf.3 png.5
+DOCS=	ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO \
+	libpng-manual.txt
+
+CFLAGS+= -W -Wall
+CPPFLAGS+= -I${.CURDIR}
+
+NOPROFILE= Yes
+
+CLEANFILES+= pngtest.o pngtest pnglibconf.h
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt
+
+.c.o:
+	${CC} -c ${CPPFLAGS} ${CFLAGS} -o $@ $<
+
+pnglibconf.h: ${PNGLIBCONF_H_PREBUILT}
+	cp ${PNGLIBCONF_H_PREBUILT} $@
+
+pngtest.o:	pngtest.c
+	${CC} -c ${CPPFLAGS} ${CFLAGS} ${.ALLSRC} -o ${.TARGET}
+
+pngtest:	pngtest.o
+	${CC} ${LDFLAGS} ${.ALLSRC} -o ${.TARGET} -L${.OBJDIR} -lpng -lz -lm
+
+test:	pngtest
+	cd ${.OBJDIR} && env \
+		LD_LIBRARY_PATH="${.OBJDIR}" ${.OBJDIR}/pngtest
+
+beforeinstall:
+	if [ ! -d ${DESTDIR}${PREFIX}/include/libpng ]; then \
+	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${PREFIX}/include; \
+	fi
+	if [ ! -d ${DESTDIR}${LIBDIR} ]; then \
+	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${LIBDIR}; \
+	fi
+	if [ ! -d ${DESTDIR}${LIBDIR}/debug ]; then \
+	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${LIBDIR}/debug; \
+	fi
+	if [ ! -d ${DESTDIR}${MANDIR}3 ]; then \
+	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${MANDIR}3; \
+	fi
+	if [ ! -d ${DESTDIR}${MANDIR}5 ]; then \
+	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${MANDIR}5; \
+	fi
+	if [ ! -d ${DESTDIR}${PREFIX}/share/doc/png ]; then \
+	  ${INSTALL} -d -o root -g wheel ${DESTDIR}${PREFIX}/share/doc/png; \
+	fi
+
+afterinstall:
+	@rm -f ${DESTDIR}${LIBDIR}/libpng_pic.a
+	@rm -f ${DESTDIR}${LIBDIR}/debug/libpng.a
+	@rm -f ${DESTDIR}${PREFIX}/include/png.h
+	@rm -f ${DESTDIR}${PREFIX}/include/pngconf.h
+	@rm -f ${DESTDIR}${PREFIX}/include/pnglibconf.h
+	@rmdir ${DESTDIR}${LIBDIR}/debug 2>/dev/null || true
+	${INSTALL} ${INSTALL_COPY} -o ${SHAREOWN} -g ${SHAREGRP} \
+		-m ${NONBINMODE} ${HDRS} ${DESTDIR}${PREFIX}/include
+	${INSTALL} ${INSTALL_COPY} -o ${SHAREOWN} -g ${SHAREGRP} \
+		-m ${NONBINMODE} ${HDRS} ${DESTDIR}${PREFIX}/include
+	${INSTALL} ${INSTALL_COPY} -o ${SHAREOWN} -g ${SHAREGRP} \
+		-m ${NONBINMODE} ${DOCS} ${DESTDIR}${PREFIX}/share/doc/png
+
+.include <bsd.lib.mk>
diff --git a/extern/libpng/scripts/makefile.sco b/extern/libpng/scripts/makefile.sco
new file mode 100644
index 0000000000..01d7eaaaaf
--- /dev/null
+++ b/extern/libpng/scripts/makefile.sco
@@ -0,0 +1,226 @@
+# makefile for SCO OSr5  ELF and Unixware 7 with Native cc
+# Contributed by Mike Hopkirk (hops at sco.com) modified from Makefile.lnx
+#   force ELF build dynamic linking, SONAME setting in lib and RPATH in app
+# Copyright (C) 2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1998 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME = libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+CC=cc
+AR_RC=ar rc
+MKDIR_P=mkdir
+LN_SF=ln -f -s
+RANLIB=echo
+CP=cp
+RM_F=/bin/rm -f
+
+# where make install puts libpng.a, $(OLDSO)*, and png.h
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+CPPFLAGS=-I$(ZLIBINC)
+CFLAGS= -dy -belf -O3
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz -lm
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo ccopts=\"-belf\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(CC) -G  -Wl,-h,$(LIBSOMAJ) -o $(LIBSOMAJ) \
+	 $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	LD_RUN_PATH=.:$(ZLIBLIB) $(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	-@$(RM_F) $(DI)/png.h
+	-@$(RM_F) $(DI)/pngconf.h
+	-@$(RM_F) $(DI)/pnglibconf.h
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	$(CC) $(CPPFLAGS) $(CFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png libpng-config \
+	$(LIBSO) $(LIBSOMAJ)* pngtest-static pngtesti \
+	pnglibconf.h libpng.pc
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.sggcc b/extern/libpng/scripts/makefile.sggcc
new file mode 100644
index 0000000000..82efe7a220
--- /dev/null
+++ b/extern/libpng/scripts/makefile.sggcc
@@ -0,0 +1,236 @@
+# makefile for libpng.a and libpng16.so, SGI IRIX with 'cc'
+# Copyright (C) 2001-2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+AR_RC=ar rc
+CC=gcc
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+RANLIB=echo
+CP=cp
+RM_F=/bin/rm -f
+
+# Where make install puts libpng.a, libpng16.so, and libpng16/png.h
+# Prefix must be a full pathname.
+
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib32
+#ZLIBINC=/usr/local/include
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+# ABI can be blank to use default for your system, -32, -o32, -n32, or -64
+# See "man abi".  zlib must be built with the same ABI.
+ABI=
+
+WARNMORE=
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=$(ABI) -O $(WARNMORE) -fPIC -mabi=n32 # -g
+LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm
+LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
+	-set_version sgi$(PNGMAJ).0
+# See "man dso" for info about shared objects
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+#LIBPATH=$(exec_prefix)/lib32
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS =  png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest shared libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+shared: $(LIBSOMAJ)
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo ccopts=\"$(ABI)\"; \
+	echo cppflags=\"\"; \
+	echo ldopts=\"$(ABI)\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo libdir=\"$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJS)
+	$(LDSHARED) -o $@ $(OBJS)
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	echo
+	echo Testing local static library.
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) \
+	   -rpath $(ZLIBLIB):$(DL) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) \
+	   -rpath $(ZLIBLIB):`$(BINPATH)/$(LIBNAME)-config --libdir` \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) libpng.a pngtest pngtesti pngout.png libpng.pc \
+	so_locations libpng-config $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.sgi b/extern/libpng/scripts/makefile.sgi
new file mode 100644
index 0000000000..5d9c23fa90
--- /dev/null
+++ b/extern/libpng/scripts/makefile.sgi
@@ -0,0 +1,237 @@
+# makefile for libpng.a and libpng16.so, SGI IRIX with 'cc'
+# Copyright (C) 2001-2002, 2006, 2007, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+AR_RC=ar rc
+CC=cc
+MKDIR_P=mkdir -p
+LN_SF=ln -sf
+RANLIB=echo
+CP=cp
+RM_F=/bin/rm -f
+
+# Where make install puts libpng.a, libpng16.so, and libpng16/png.h
+# Prefix must be a full pathname.
+
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib32
+#ZLIBINC=/usr/local/include
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+# ABI can be blank to use default for your system, -32, -o32, -n32, or -64
+# See "man abi".  zlib must be built with the same ABI.
+ABI=
+
+WARNMORE=-fullwarn
+# Note: -KPIC is the default anyhow
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+#CFLAGS= $(ABI) -O $(WARNMORE) -KPIC # -g
+CFLAGS=$(ABI) -O $(WARNMORE)
+LDFLAGS_A=$(ABI) -L. -L$(ZLIBLIB) -lpng16 -lz -lm
+LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm
+LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
+	-set_version sgi$(PNGMAJ).0
+# See "man dso" for info about shared objects
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+#LIBPATH=$(exec_prefix)/lib32
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS =  png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest shared libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo ccopts=\"$(ABI)\"; \
+	echo ldopts=\"$(ABI)\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo libdir=\"$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJS)
+	$(LDSHARED) -o $@ $(OBJS)
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	echo
+	echo Testing local static library.
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(DL) -L$(ZLIBLIB) \
+	   -rpath $(ZLIBLIB):$(DL) \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -L$(ZLIBLIB) \
+	   -rpath $(ZLIBLIB):`$(BINPATH)/$(LIBNAME)-config --libdir` \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png libpng.pc libpng-config \
+	$(LIBSO) $(LIBSOMAJ)* \
+	so_locations pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.so9 b/extern/libpng/scripts/makefile.so9
new file mode 100644
index 0000000000..93166f30e8
--- /dev/null
+++ b/extern/libpng/scripts/makefile.so9
@@ -0,0 +1,247 @@
+# makefile for libpng on Solaris 9 (beta) with Forte cc
+# Updated by Chad Schrock for Solaris 9
+# Contributed by William L. Sebok, based on makefile.linux
+# Copyright (C) 2002, 2006, 2008, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1998-2001 Greg Roelofs
+# Copyright (C) 1996-1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+PNGMAJ = 16
+LIBNAME = libpng16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+# gcc 2.95 doesn't work.
+CC=cc
+AR_RC=ar rc
+MKDIR_P=mkdir -p
+LN_SF=ln -f -s
+RANLIB=echo
+CP=cp
+RM_F=/bin/rm -f
+
+# Where make install puts libpng.a, $(OLDSO)*, and png.h
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located
+# Changing these to ../zlib poses a security risk.  If you want
+# to have zlib in an adjacent directory, specify the full path instead of "..".
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+#Use the preinstalled zlib that comes with Solaris 9:
+ZLIBLIB=/usr/lib
+ZLIBINC=/usr/include
+
+#WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+#CFLAGS=-W -Wall -O3 $(WARNMORE) -g
+CFLAGS=-O3
+LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo R_opts=\"-R$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	@case "`type ld`" in *ucb*) \
+	echo; \
+	echo '## WARNING:'; \
+	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
+	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
+	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
+	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
+	echo '## at all.  If it is, things are likely to break because of'; \
+	echo '## the libucb dependency that is created.'; \
+	echo; \
+	;; \
+	esac
+	$(LD) -G -h $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags` \
+	   -L$(DL) -L$(ZLIBLIB)  -R$(ZLIBLIB) -R$(DL)
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
+	   -L$(ZLIBLIB) -R$(ZLIBLIB)
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
+	libpng-config $(LIBSO) $(LIBSOMAJ)* \
+	libpng.pc pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.solaris b/extern/libpng/scripts/makefile.solaris
new file mode 100644
index 0000000000..f6d7b5860e
--- /dev/null
+++ b/extern/libpng/scripts/makefile.solaris
@@ -0,0 +1,243 @@
+# makefile for libpng on Solaris 2.x with gcc
+# Copyright (C) 2004, 2006-2008, 2010-2014 Glenn Randers-Pehrson
+# Contributed by William L. Sebok, based on makefile.linux
+# Copyright (C) 1998 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME = libpng16
+PNGMAJ = 16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+LIBSOREL=$(LIBSOMAJ).$(RELEASE)
+OLDSO=libpng.so
+
+# Utilities:
+AR_RC=ar rc
+CC=gcc
+MKDIR_P=mkdir -p
+LN_SF=ln -f -s
+RANLIB=echo
+CP=cp
+RM_F=/bin/rm -f
+
+# Where make install puts libpng.a, libpng16.so*, and png.h
+prefix=/usr/local
+exec_prefix=$(prefix)
+
+# Where the zlib library and include files are located
+# Changing these to ../zlib poses a security risk.  If you want
+# to have zlib in an adjacent directory, specify the full path instead of "..".
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+
+ZLIBLIB=/usr/local/lib
+ZLIBINC=/usr/local/include
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-W -Wall -O # $(WARNMORE) -g
+LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm
+
+INCPATH=$(prefix)/include
+LIBPATH=$(exec_prefix)/lib
+MANPATH=$(prefix)/man
+BINPATH=$(exec_prefix)/bin
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+DB=$(DESTDIR)$(BINPATH)
+DI=$(DESTDIR)$(INCPATH)
+DL=$(DESTDIR)$(LIBPATH)
+DM=$(DESTDIR)$(MANPATH)
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.pc:
+	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
+	-e s!@exec_prefix@!$(exec_prefix)! \
+	-e s!@libdir@!$(LIBPATH)! \
+	-e s!@includedir@!$(INCPATH)! \
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
+
+libpng-config:
+	( cat scripts/libpng-config-head.in; \
+	echo prefix=\"$(prefix)\"; \
+	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
+	echo cppflags=\"\"; \
+	echo L_opts=\"-L$(LIBPATH)\"; \
+	echo R_opts=\"-R$(LIBPATH)\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
+	cat scripts/libpng-config-body.in ) > libpng-config
+	chmod +x libpng-config
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	@case "`type ld`" in *ucb*) \
+	echo; \
+	echo '## WARNING:'; \
+	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
+	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
+	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
+	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
+	echo '## at all.  If it is, things are likely to break because of'; \
+	echo '## the libucb dependency that is created.'; \
+	echo; \
+	;; \
+	esac
+	$(LD) -G -h $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install-headers: png.h pngconf.h pnglibconf.h
+	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
+	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
+	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
+	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
+	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
+	-@$(RM_F) $(DI)/libpng
+	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
+
+install-static: install-headers libpng.a
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	cp libpng.a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
+
+install-shared: install-headers $(LIBSOMAJ) libpng.pc
+	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
+	-@$(RM_F) $(DL)/$(LIBSO)
+	-@$(RM_F) $(DL)/$(LIBSOREL)
+	-@$(RM_F) $(DL)/$(OLDSO)
+	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
+	chmod 755 $(DL)/$(LIBSOREL)
+	(cd $(DL); \
+	$(LN_SF) $(LIBSOREL) $(LIBSO); \
+	$(LN_SF) $(LIBSO) $(OLDSO))
+	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
+	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
+	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
+	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
+	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
+	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
+
+install-man: libpng.3 libpngpf.3 png.5
+	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
+	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
+	-@$(RM_F) $(DM)/man3/libpng.3
+	-@$(RM_F) $(DM)/man3/libpngpf.3
+	cp libpng.3 $(DM)/man3
+	cp libpngpf.3 $(DM)/man3
+	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
+	-@$(RM_F) $(DM)/man5/png.5
+	cp png.5 $(DM)/man5
+
+install-config: libpng-config
+	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
+	-@$(RM_F) $(DB)/libpng-config
+	-@$(RM_F) $(DB)/$(LIBNAME)-config
+	cp libpng-config $(DB)/$(LIBNAME)-config
+	chmod 755 $(DB)/$(LIBNAME)-config
+	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
+
+install: install-static install-shared install-man install-config
+
+# If you installed in $(DESTDIR), test-installed won't work until you
+# move the library to its final location.  Use test-dd to test it
+# before then.
+
+test-dd:
+	echo
+	echo Testing installed dynamic shared library in $(DL).
+	$(CC) -I$(DI) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags` \
+	   -L$(DL) -L$(ZLIBLIB) -R$(ZLIBLIB) -R$(DL)
+	./pngtestd pngtest.png
+
+test-installed:
+	echo
+	echo Testing installed dynamic shared library.
+	$(CC) $(CPPFLAGS) \
+	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
+	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
+	   -L$(ZLIBLIB) -R$(ZLIBLIB)
+	./pngtesti pngtest.png
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
+	libpng-config $(LIBSO) $(LIBSOMAJ)* \
+	libpng.pc pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.std b/extern/libpng/scripts/makefile.std
new file mode 100644
index 0000000000..2f4871df90
--- /dev/null
+++ b/extern/libpng/scripts/makefile.std
@@ -0,0 +1,134 @@
+# makefile for libpng
+# Copyright (C) 2002, 2006, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# where make install puts libpng.a and png.h
+prefix=/usr/local
+INCPATH=$(prefix)/include
+LIBPATH=$(prefix)/lib
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+CC = cc
+AR_RC = ar rc
+MKDIR_P = mkdir
+LN_SF = ln -sf
+RANLIB = ranlib
+CP = cp
+RM_F = rm -f
+AWK = awk
+SED = sed
+CPP = $(CC) -E
+ECHO = echo
+
+DFNFLAGS = # DFNFLAGS contains -D options to use in the libpng build
+DFA_EXTRA = # extra files that can be used to control configuration
+CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS = -O # -g
+LDFLAGS = -L. -L$(ZLIBLIB) -lpng -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest
+
+# The standard pnglibconf.h exists as scripts/pnglibconf.h.prebuilt,
+# copy this if the following doesn't work.
+pnglibconf.h: pnglibconf.dfn
+	$(RM_F) $@ pnglibconf.c pnglibconf.out pnglibconf.tmp
+	$(ECHO) '#include "pnglibconf.dfn"' >pnglibconf.c
+	$(ECHO) "If '$(CC) -E' crashes try /lib/cpp (e.g. CPP='/lib/cpp')" >&2
+	$(CPP) $(DFNFLAGS) pnglibconf.c >pnglibconf.out
+	$(AWK) -f "scripts/dfn.awk" out="pnglibconf.tmp" pnglibconf.out 1>&2
+	mv pnglibconf.tmp $@
+
+pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+	$(RM_F) $@ pnglibconf.pre pnglibconf.tmp
+	$(ECHO) "Calling $(AWK) from scripts/pnglibconf.mak" >&2
+	$(ECHO) "If 'awk' crashes try a better awk (e.g. AWK='nawk')" >&2
+	$(AWK) -f scripts/options.awk out="pnglibconf.pre"\
+	    version=search pngconf.h scripts/pnglibconf.dfa\
+	    pngusr.dfa $(DFA_XTRA) 1>&2
+	$(AWK) -f scripts/options.awk out="pnglibconf.tmp" pnglibconf.pre 1>&2
+	mv pnglibconf.tmp $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@  $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install: libpng.a pnglibconf.h
+	-@$(MKDIR_P) $(DESTDIR)$(INCPATH)
+	-@$(MKDIR_P) $(DESTDIR)$(INCPATH)/libpng
+	-@$(MKDIR_P) $(DESTDIR)$(LIBPATH)
+	-@$(RM_F) $(DESTDIR)$(INCPATH)/png.h
+	-@$(RM_F) $(DESTDIR)$(INCPATH)/pngconf.h
+	-@$(RM_F) $(DESTDIR)$(INCPATH)/pnglibconf.h
+	cp png.h $(DESTDIR)$(INCPATH)/libpng
+	cp pngconf.h $(DESTDIR)$(INCPATH)/libpng
+	cp pnglibconf.h $(DESTDIR)$(INCPATH)/libpng
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/png.h
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pngconf.h
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pnglibconf.h
+	(cd $(DESTDIR)$(INCPATH); ln -f -s libpng/* .)
+	cp libpng.a $(DESTDIR)$(LIBPATH)
+	chmod 644 $(DESTDIR)$(LIBPATH)/libpng.a
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.h pnglibconf.c \
+	pnglibconf.out
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.sunos b/extern/libpng/scripts/makefile.sunos
new file mode 100644
index 0000000000..9a0e28e722
--- /dev/null
+++ b/extern/libpng/scripts/makefile.sunos
@@ -0,0 +1,115 @@
+# makefile for libpng
+# Copyright (C) 2002, 2006, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# where make install puts libpng.a and png.h
+prefix=/usr/local
+INCPATH=$(prefix)/include
+LIBPATH=$(prefix)/lib
+
+# override DESTDIR= on the make install command line to easily support
+# installing into a temporary location.  Example:
+#
+#    make install DESTDIR=/tmp/build/libpng
+#
+# If you're going to install into a temporary location
+# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
+# you execute make install.
+DESTDIR=
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow -Wconversion \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes
+
+CC=gcc
+AR_RC=ar rc
+MKDIR_P=mkdir -p
+LN_SF=ln -f -s
+RANLIB=ranlib
+CP=cp
+RM_F=/bin/rm -f
+
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-O # $(WARNMORE)
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR_RC) $@  $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install: libpng.a
+	-@$(MKDIR_P) $(DESTDIR)$(INCPATH)
+	-@$(MKDIR_P) $(DESTDIR)$(INCPATH)/libpng
+	-@$(MKDIR_P) $(DESTDIR)$(LIBPATH)
+	-@$(RM_F) $(DESTDIR)$(INCPATH)/png.h
+	-@$(RM_F) $(DESTDIR)$(INCPATH)/pngconf.h
+	-@$(RM_F) $(DESTDIR)$(INCPATH)/pnglibconf.h
+	cp png.h $(DESTDIR)$(INCPATH)/libpng
+	cp pngconf.h $(DESTDIR)$(INCPATH)/libpng
+	cp pnglibconf.h $(DESTDIR)$(INCPATH)/libpng
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/png.h
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pngconf.h
+	chmod 644 $(DESTDIR)$(INCPATH)/libpng/pnglibconf.h
+	(cd $(DESTDIR)$(INCPATH); $(LN_SF) libpng/* .)
+	cp libpng.a $(DESTDIR)$(LIBPATH)
+	chmod 644 $(DESTDIR)$(LIBPATH)/libpng.a
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.h
+
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/extern/libpng/scripts/makefile.vcwin32 b/extern/libpng/scripts/makefile.vcwin32
new file mode 100644
index 0000000000..2bd143cc0a
--- /dev/null
+++ b/extern/libpng/scripts/makefile.vcwin32
@@ -0,0 +1,113 @@
+# makefile for libpng
+# Copyright (C) 1998 Tim Wegner
+# Copyright (C) 2006,2009,2011,2014 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Assumes that zlib.lib, zconf.h, and zlib.h have been copied to ..\zlib
+# To use, do "nmake /f scripts\makefile.vcwin32"
+
+# -------- Microsoft Visual C++ 2.0 and later --------
+
+# Compiler, linker, librarian and other tools
+CC = cl
+LD = link
+AR = lib
+CPPFLAGS = -I..\zlib
+CFLAGS  = -nologo -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -MD -O2 -W3
+LDFLAGS = -nologo
+ARFLAGS = -nologo
+CP = copy
+RM = del
+
+# Pre-built configuration
+# See scripts\pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
+
+# File extensions
+O=.obj
+
+#uncomment next to put error messages in a file
+#ERRFILE= >> pngerrs.log
+
+# Variables
+OBJS1 = png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O)
+OBJS2 = pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O)
+OBJS3 = pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
+OBJS  = $(OBJS1) $(OBJS2) $(OBJS3)
+
+# Targets
+all: libpng.lib
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngget$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngmem$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+libpng.lib: $(OBJS)
+	-$(RM) $@
+	$(AR) $(ARFLAGS) -out:$@ $(OBJS) $(ERRFILE)
+
+pngtest$(O): png.h pngconf.h pnglibconf.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngtest.exe: pngtest$(O) libpng.lib
+	$(LD) $(LDFLAGS) -out:$@ pngtest$(O) libpng.lib ..\zlib\zlib.lib $(ERRFILE)
+
+test: pngtest.exe
+	pngtest
+
+clean:
+	-$(RM) *$(O)
+	-$(RM) libpng.lib
+	-$(RM) pnglibconf.h
+	-$(RM) pngtest.exe
+	-$(RM) pngout.png
+
+# End of makefile for libpng
+
diff --git a/extern/libpng/scripts/makevms.com b/extern/libpng/scripts/makevms.com
new file mode 100644
index 0000000000..f6c326103c
--- /dev/null
+++ b/extern/libpng/scripts/makevms.com
@@ -0,0 +1,142 @@
+$! make libpng under VMS
+$!
+$!
+$! Check for MMK/MMS
+$!
+$! This procedure accepts one parameter (contrib), which causes it to build
+$! the programs from the contrib directory instead of libpng.
+$!
+$ p1 = f$edit(p1,"UPCASE")
+$ if p1 .eqs. "CONTRIB"
+$ then
+$   set def [.contrib.gregbook]
+$   @makevms
+$   set def [-.pngminus]
+$   @makevms
+$   set def [--]
+$   exit
+$ endif
+$ Make = ""
+$ If F$Search ("Sys$System:MMS.EXE") .nes. "" Then Make = "MMS"
+$ If F$Type (MMK) .eqs. "STRING" Then Make = "MMK"
+$!
+$! Look for the compiler used
+$!
+$ zlibsrc = "[-.zlib]"
+$ ccopt="/include=''zlibsrc'"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$!
+$! Build the thing plain or with mms/mmk
+$!
+$ write sys$output "Compiling Libpng sources ..."
+$ if make.eqs.""
+$  then
+$   dele pngtest.obj;*
+$   CALL MAKE png.OBJ "cc ''CCOPT' png" -
+	png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngset.OBJ "cc ''CCOPT' pngset" -
+	pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngget.OBJ "cc ''CCOPT' pngget" -
+	pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngread.OBJ "cc ''CCOPT' pngread" -
+	pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngpread.OBJ "cc ''CCOPT' pngpread" -
+	pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngrtran.OBJ "cc ''CCOPT' pngrtran" -
+	pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngrutil.OBJ "cc ''CCOPT' pngrutil" -
+	pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngerror.OBJ "cc ''CCOPT' pngerror" -
+	pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngmem.OBJ "cc ''CCOPT' pngmem" -
+	pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngrio.OBJ "cc ''CCOPT' pngrio" -
+	pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngwio.OBJ "cc ''CCOPT' pngwio" -
+	pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngtrans.OBJ "cc ''CCOPT' pngtrans" -
+	pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngwrite.OBJ "cc ''CCOPT' pngwrite" -
+	pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngwtran.OBJ "cc ''CCOPT' pngwtran" -
+	pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngwutil.OBJ "cc ''CCOPT' pngwutil" -
+	pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   write sys$output "Building Libpng ..."
+$   CALL MAKE libpng.OLB "lib/crea libpng.olb *.obj" *.OBJ
+$   write sys$output "Building pngtest..."
+$   CALL MAKE pngtest.OBJ "cc ''CCOPT' pngtest" -
+	pngtest.c png.h pngconf.h pnglibconf.h
+$   call make pngtest.exe -
+	"LINK pngtest,libpng.olb/lib,''zlibsrc'libz.olb/lib" -
+	pngtest.obj libpng.olb
+$   write sys$output "Testing Libpng..."
+$   run pngtest
+$  else
+$   if f$search("DESCRIP.MMS") .eqs. "" then copy/nolog [.SCRIPTS]DESCRIP.MMS []
+$   'make'/macro=('comp',zlibsrc='zlibsrc')
+$  endif
+$ write sys$output "Libpng build completed"
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE
diff --git a/extern/libpng/scripts/options.awk b/extern/libpng/scripts/options.awk
new file mode 100755
index 0000000000..fef5dfd78b
--- /dev/null
+++ b/extern/libpng/scripts/options.awk
@@ -0,0 +1,898 @@
+#!/bin/awk -f
+# scripts/options.awk - library build configuration control
+#
+# last changed in libpng version 1.6.11 - June 5, 2014
+#
+# Copyright (c) 1998-2014 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# The output of this script is written to the file given by
+# the variable 'out'.  The script is run twice, once with
+# an intermediate output file, 'options.tmp' then again on
+# that file to produce the final output:
+#
+#  awk -f scripts/options.awk out=options.tmp scripts/options.dfa 1>&2
+#  awk -f scripts/options.awk out=options.dfn options.tmp 1>&2
+#
+# Some options may be specified on the command line:
+#
+#  deb=1            Causes debugging to be output
+#  logunsupported=1 Causes all options to be recorded in the output
+#  everything=off   Causes all options to be disabled by default
+#  everything=on    Causes all options to be enabled by default
+#
+# If awk fails on your platform, try nawk instead.
+#
+# These options may also be specified in the original input file (and
+# are copied to the preprocessed file).
+
+BEGIN{
+   out=""                       # intermediate, preprocessed, file
+   pre=-1                       # preprocess (first line)
+   version="libpng version unknown" # version information
+   version_file=""              # where to find the version
+   err=0                        # in-line exit sets this
+   # The following definitions prevent the C preprocessor noticing the lines
+   # that will be in the final output file.  Some C preprocessors tokenise
+   # the lines, for example by inserting spaces around operators, and all
+   # C preprocessors notice lines that start with '#', most remove comments.
+   # The technique adopted here is to make the final output lines into
+   # C strings (enclosed in double quotes), preceded by PNG_DFN.  As a
+   # consequence the output cannot contain a 'raw' double quote - instead put
+   # @' in, this will be replaced by a single " afterward.  See the parser
+   # script dfn.awk for more capabilities (not required here).  Note that if
+   # you need a " in a 'setting' in pnglibconf.dfa it must also be @'!
+   dq="@'"                      # For a single double quote
+   start=" PNG_DFN \""          # Start stuff to output (can't contain a "!)
+   end="\" "                    # End stuff to output
+   subs="@\" "                  # Substitute start (substitute a C macro)
+   sube=" \"@"                  # Substitute end
+   comment=start "/*"           # Comment start
+   cend="*/" end                # Comment end
+   def=start "#define PNG_"     # Arbitrary define
+   sup="_SUPPORTED" end         # end supported option
+   und=comment "#undef PNG_"    # Unsupported option
+   une="_SUPPORTED" cend        # end unsupported option
+   error=start "ERROR:"         # error message, terminate with 'end'
+
+   # Variables
+   deb=0                        # debug - set on command line
+   everything=""                # do not override defaults
+   logunsupported=0             # write unsupported options too
+
+   # Precreate arrays
+   # for each option:
+   option[""] = ""    # list of all options: default enabled/disabled
+   done[""] = 1       # marks option as having been output
+   requires[""] = ""  # requires by option
+   iffs[""] = ""      # if by option
+   enabledby[""] = "" # options that enable it by option
+   sets[""] = ""      # settings set by each option
+   setval[""] = ""    # value to set (indexed: 'option sets[option]')
+   # for each setting:
+   setting[""] = ""   # requires by setting
+   defaults[""] = ""  # used for a defaulted value
+   doneset[""] = 1    # marks setting as having been output
+   r[""] = ""         # Temporary array
+
+   # For decorating the output file
+   protect = ""
+}
+
+# The output file must be specified before any input:
+out == "" {
+   print "out=output.file must be given on the command line"
+   err = 1
+   exit 1
+}
+
+# The very first line indicates whether we are reading pre-processed
+# input or not, this must come *first* because 'PREPROCESSED' needs
+# to be the very first line in the temporary file.
+pre == -1{
+   if ($0 == "PREPROCESSED") {
+      pre = 0
+      next
+   } else {
+      pre = 1
+      print "PREPROCESSED" >out
+      # And fall through to continue processing
+   }
+}
+
+# While pre-processing if version is set to "search" look for a version string
+# in the following file.
+pre && version == "search" && version_file == ""{
+   version_file = FILENAME
+}
+
+pre && version == "search" && version_file != FILENAME{
+   print "version string not found in", version_file
+   err = 1
+   exit 1
+}
+
+pre && version == "search" && $0 ~ /^ \* libpng version/{
+   version = substr($0, 4)
+   print "version =", version >out
+   next
+}
+
+pre && FILENAME == version_file{
+   next
+}
+
+# variable=value
+#   Sets the given variable to the given value (the syntax is fairly
+#   free form, except for deb (you are expected to understand how to
+#   set the debug variable...)
+#
+#   This happens before the check on 'pre' below skips most of the
+#   rest of the actions, so the variable settings happen during
+#   preprocessing but are recorded in the END action too.  This
+#   allows them to be set on the command line too.
+$0 ~ /^[ 	]*version[ 	]*=/{
+   sub(/^[  ]*version[  ]*=[  ]*/, "")
+   version = $0
+   next
+}
+$0 ~ /^[ 	]*everything[ 	=]*off[ 	]*$/{
+   everything = "off"
+   next
+}
+$0 ~ /^[ 	]*everything[ 	=]*on[ 	]*$/{
+   everything = "on"
+   next
+}
+$0 ~ /^[ 	]*logunsupported[ 	=]*0[ 	]*$/{
+   logunsupported = 0
+   next
+}
+$0 ~ /^[ 	]*logunsupported[ 	=]*1[ 	]*$/{
+   logunsupported = 1
+   next
+}
+$1 == "deb" && $2 == "=" && NF == 3{
+   deb = $3
+   next
+}
+
+# Preprocessing - this just copies the input file with lines
+# that need preprocessing (just chunk at present) expanded
+# The bare "pre" instead of "pre != 0" crashes under Sunos awk
+pre && $1 != "chunk"{
+   print >out
+   next
+}
+
+# The first characters of the line determine how it is processed,
+# leading spaces are ignored.  In general tokens that are not
+# keywords are the names of options.  An option 'name' is
+# controlled by the definition of the corresponding macros:
+#
+#   PNG_name_SUPPORTED    The option is turned on
+#   PNG_NO_name
+#   PNG_NO_name_SUPPORTED If the first macro is not defined
+#                         either of these will turn the option off
+#
+# If none of these macros are defined the option is turned on, unless
+# the keyword 'off' is given in a line relating to the option.  The
+# keyword 'on' can also be given, but it will be ignored (since it is
+# the default.)
+#
+# In the syntax below a 'name' is indicated by "NAME", other macro
+# values are indicated by "MACRO", as with "NAME" the leading "PNG_"
+# is omitted, but in this case the "NO_" prefix and the "_SUPPORTED"
+# suffix are never used.
+#
+# Each line is introduced by a keyword - the first non-space characters
+# on the line.  A line starting with a '#' is a comment - it is totally
+# ignored.  Keywords are as follows, a NAME, is simply a macro name
+# without the leading PNG_, PNG_NO_ or the trailing _SUPPORTED.
+
+$1 ~ /^#/ || $0 ~ /^[ 	]*$/{
+   next
+}
+
+# com <comment>
+#   The whole line is placed in the output file as a comment with
+#   the preceding 'com' removed
+$1 == "com"{
+   if (NF > 1) {
+      # sub(/^[ 	]*com[ 	]*/, "")
+      $1 = ""
+      print comment $0, cend >out
+   } else
+      print start end >out
+   next
+}
+
+# version
+#   Inserts a version comment
+$1 == "version" && NF == 1{
+   if (version == "") {
+      print "ERROR: no version string set"
+      err = 1 # prevent END{} running
+      exit 1
+   }
+
+   print comment, version, cend >out
+   next
+}
+
+# file output input protect
+#   Informational: the official name of the input file (without
+#   make generated local directories), the official name of the
+#   output file and, if required, a name to use in a protection
+#   macro for the contents.
+$1 == "file" && NF >= 2{
+   print comment, $2, cend >out
+   print comment, "Machine generated file: DO NOT EDIT", cend >out
+   if (NF >= 3)
+      print comment, "Derived from:", $3, cend >out
+   protect = $4
+   if (protect != "") {
+      print start "#ifndef", protect end >out
+      print start "#define", protect end >out
+   }
+   next
+}
+
+# option NAME ( (requires|enables|if) NAME* | on | off | disabled |
+#                sets SETTING VALUE+ )*
+#     
+#   Declares an option 'NAME' and describes its default setting (disabled)
+#   and its relationship to other options.  The option is disabled
+#   unless *all* the options listed after 'requires' are set and at
+#   least one of the options listed after 'if' is set.  If the
+#   option is set then it turns on all the options listed after 'enables'.
+#
+#   Note that "enables" takes priority over the required/if/disabled/off
+#   setting of the target option.
+#
+#   The definition file may list an option as 'disabled': off by default,
+#   otherwise the option is enabled: on by default.  A later (and it must
+#   be later) entry may turn an option on or off explicitly.
+
+$1 == "option" && NF >= 2{
+   opt = $2
+   sub(/,$/,"",opt)
+   onoff = option[opt]  # records current (and the default is "", enabled)
+   key = ""
+   istart = 3
+   do {
+      if (istart == 1) {     # continuation line
+         val = getline
+
+         if (val != 1) { # error reading it
+            if (val == 0)
+               print "option", opt ": ERROR: missing continuation line"
+            else
+               print "option", opt ": ERROR: error reading continuation line"
+
+            # This is a hard error
+            err = 1 # prevent END{} running
+            exit 1
+         }
+      }
+
+      for (i=istart; i<=NF; ++i) {
+         val=$(i)
+         sub(/,$/,"",val)
+         if (val == "on" || val == "off" || val == "disabled" || val =="enabled") {
+            key = ""
+            if (onoff != val) {
+               # on or off can zap disabled or enabled:
+               if (onoff == "" || (onoff == "disabled" || onoff == "enabled") &&
+                   (val == "on" || val == "off")) {
+                  # It's easy to mis-spell the option when turning it
+                  # on or off, so warn about it here:
+                  if (onoff == "" && (val == "on" || val == "off")) {
+                     print "option", opt ": ERROR: turning unrecognized option", val
+                     # For the moment error out - it is safer
+                     err = 1 # prevent END{} running
+                     exit 1
+                  }
+                  onoff = val
+               } else {
+                  # Print a message, otherwise the error
+                  # below is incomprehensible
+                  print "option", opt ": currently", onoff ": attempt to turn", val
+                  break
+               }
+            }
+         } else if (val == "requires" || val == "if" || val == "enables" || val =="sets") {
+            key = val
+         } else if (key == "requires") {
+            requires[opt] = requires[opt] " " val
+         } else if (key == "if") {
+            iffs[opt] = iffs[opt] " " val
+         } else if (key == "enables") {
+            enabledby[val] = enabledby[val] " " opt
+         } else if (key == "sets") {
+            sets[opt] = sets[opt] " " val
+            key = "setval"
+            set = val
+         } else if (key == "setval") {
+            setval[opt " " set] = setval[opt " " set] " " val
+         } else
+            break # bad line format
+      }
+
+      istart = 1
+   } while (i > NF && $0 ~ /,$/)
+
+   if (i > NF) {
+      # Set the option, defaulting to 'enabled'
+      if (onoff == "") onoff = "enabled"
+      option[opt] = onoff
+      next
+   }
+   # Else fall through to the error handler
+}
+
+# chunk NAME [requires OPT] [enables LIST] [on|off|disabled]
+#   Expands to the 'option' settings appropriate to the reading and
+#   writing of an ancillary PNG chunk 'NAME':
+#
+#   option READ_NAME requires READ_ANCILLARY_CHUNKS [READ_OPT]
+#   option READ_NAME enables NAME LIST
+#   [option READ_NAME off]
+#   option WRITE_NAME requires WRITE_ANCILLARY_CHUNKS [WRITE_OPT]
+#   option WRITE_NAME enables NAME LIST
+#   [option WRITE_NAME off]
+
+pre != 0 && $1 == "chunk" && NF >= 2{
+   # 'chunk' is handled on the first pass by writing appropriate
+   # 'option' lines into the intermediate file.
+   opt = $2
+   sub(/,$/,"",opt)
+   onoff = ""
+   reqread = ""
+   reqwrite = ""
+   enables = ""
+   req = 0
+   istart = 3
+   do {
+      if (istart == 1) {     # continuation line
+         val = getline
+
+         if (val != 1) { # error reading it
+            if (val == 0)
+               print "chunk", opt ": ERROR: missing continuation line"
+            else
+               print "chunk", opt ": ERROR: error reading continuation line"
+
+            # This is a hard error
+            err = 1 # prevent END{} running
+            exit 1
+         }
+      }
+
+      # read the keywords/additional OPTS
+      for (i=istart; i<=NF; ++i) {
+         val = $(i)
+         sub(/,$/,"",val)
+         if (val == "on" || val == "off" || val == "disabled") {
+            if (onoff != val) {
+               if (onoff == "")
+                  onoff = val
+               else
+                  break # on/off conflict
+            }
+            req = 0
+         } else if (val == "requires")
+            req = 1
+         else if (val == "enables")
+            req = 2
+         else if (req == 1){
+            reqread = reqread " READ_" val
+            reqwrite = reqwrite " WRITE_" val
+         } else if (req == 2)
+            enables = enables " " val
+         else
+            break # bad line: handled below
+      }
+
+      istart = 1
+   } while (i > NF && $0 ~ /,$/)
+
+   if (i > NF) {
+      # Output new 'option' lines to the intermediate file (out)
+      print "option READ_" opt, "requires READ_ANCILLARY_CHUNKS" reqread, "enables", opt enables , onoff >out
+      print "option WRITE_" opt, "requires WRITE_ANCILLARY_CHUNKS" reqwrite, "enables", opt enables, onoff >out
+      next
+   }
+   # Else hit the error handler below - bad line format!
+}
+
+# setting MACRO ( requires MACRO* )* [ default VALUE ]
+#   Behaves in a similar way to 'option' without looking for NO_ or
+#   _SUPPORTED; the macro is enabled if it is defined so long as all
+#   the 'requires' macros are also defined.  The definitions may be
+#   empty, an error will be issued if the 'requires' macros are
+#   *not* defined.  If given the 'default' value is used if the
+#   macro is not defined.  The default value will be re-tokenised.
+#   (BTW: this is somewhat restrictive, it mainly exists for the
+#   support of non-standard configurations and numeric parameters,
+#   see the uses in scripts/options.dat
+
+$1 == "setting" && (NF == 2 || NF >= 3 && ($3 == "requires" || $3 == "default")){
+   reqs = ""
+   deflt = ""
+   isdef = 0
+   key = ""
+   for (i=3; i<=NF; ++i)
+      if ($(i) == "requires" || $(i) == "default") {
+         key = $(i)
+         if (key == "default") isdef = 1
+      } else if (key == "requires")
+         reqs = reqs " " $(i)
+      else if (key == "default")
+         deflt = deflt " " $(i)
+      else
+         break # Format error, handled below
+
+   setting[$2] = reqs
+   # NOTE: this overwrites a previous value silently
+   if (isdef && deflt == "")
+      deflt = " " # as a flag to force output
+   defaults[$2] = deflt
+   next
+}
+
+# The order of the dependency lines (option, chunk, setting) is irrelevant
+# - the 'enables', 'requires' and 'if' settings will be used to determine
+# the correct order in the output and the final values in pnglibconf.h are
+# not order dependent.  'requires' and 'if' entries take precedence over
+# 'enables' from other options; if an option requires another option it
+# won't be set regardless of any options that enable it unless the other
+# option is also enabled.
+#
+# Similarly 'enables' trumps a NO_ definition in CFLAGS or pngusr.h
+#
+# For simplicity cycles in the definitions are regarded as errors,
+# even if they are not ambiguous.
+# A given NAME can be specified in as many 'option' lines as required, the
+# definitions are additive.
+
+# For backwards compatibility equivalent macros may be listed thus:
+#
+# = [NO_]NAME MACRO
+#   Makes -DMACRO equivalent to -DPNG_NO_NAME or -DPNG_NAME_SUPPORTED
+#   as appropriate.
+#
+# The definition is injected into the C compiler input when encountered
+# in the second pass (so all these definitions appear *after* the @
+# lines!)
+#
+# 'NAME' is as above, but 'MACRO' is the full text of the equivalent
+# old, deprecated, macro.
+
+$1 == "=" && NF == 3{
+   print "#ifdef PNG_" $3 >out
+   if ($2 ~ /^NO_/)
+      print "#   define PNG_" $2 >out
+   else
+      print "#   define PNG_" $2 "_SUPPORTED" >out
+   print "#endif" >out
+   next
+}
+
+# Lines may be injected into the C compiler input by preceding them
+# with an "@" character.  The line is copied with just the leading
+# @ removed.
+
+$1 ~ /^@/{
+   # sub(/^[ 	]*@/, "")
+   $1 = substr($1, 2)
+   print >out
+   next
+}
+
+# Check for unrecognized lines, because of the preprocessing chunk
+# format errors will be detected on the first pass independent of
+# any other format errors.
+{
+   print "options.awk: bad line (" NR "):", $0
+   err = 1 # prevent END{} running
+   exit 1
+}
+
+# For checking purposes names that start with "ok_" or "fail_" are
+# not output to pnglibconf.h and must be either enabled or disabled
+# respectively for the build to succeed.  This allows interdependencies
+# between options of the form "at least one of" or "at most one of"
+# to be checked.  For example:
+#
+# option FLOATING_POINT enables ok_math
+# option FIXED_POINT enables ok_math
+#   This ensures that at least one of FLOATING_POINT and FIXED_POINT
+#   must be set for the build to succeed.
+#
+# option fail_math requires FLOATING_POINT FIXED_POINT
+#   This means the build will fail if *both* FLOATING_POINT and
+#   FIXED_POINT are set (this is an example; in fact both are allowed.)
+#
+# If all these options were given the build would require exactly one
+# of the names to be enabled.
+
+END{
+   # END{} gets run on an exit (a traditional awk feature)
+   if (err) exit 1
+
+   if (pre) {
+      # Record the final value of the variables
+      print "deb =", deb >out
+      if (everything != "") {
+         print "everything =", everything >out
+      }
+      print "logunsupported =", logunsupported >out
+      exit 0
+   }
+
+   # Do the options first (allowing options to set settings).  The dependency
+   # tree is thus:
+   #
+   #   name     >     name
+   #   name requires  name
+   #   name if        name
+   #   name enabledby name
+   #
+   # First build a list 'tree' by option of all the things on which
+   # it depends.
+   print "" >out
+   print "/* OPTIONS */" >out
+   print comment, "options", cend >out
+   for (opt in enabledby) tree[opt] = 1  # may not be explicit options
+   for (opt in option) if (opt != "") {
+      o = option[opt]
+      # option should always be one of the following values
+      if (o != "on" && o != "off" && o != "disabled" && o != "enabled") {
+         print "internal option error (" o ")"
+         exit 1
+      }
+      tree[opt] = ""   # so unlisted options marked
+   }
+   for (opt in tree) if (opt != "") {
+      if (tree[opt] == 1) {
+         tree[opt] = ""
+         if (option[opt] != "") {
+            print "internal error (1)"
+            exit 1
+         }
+         # Macros only listed in 'enables' remain off unless
+         # one of the enabling macros is on.
+         option[opt] = "disabled"
+      }
+
+      split("", list) # clear 'list'
+      # Now add every requires, iffs or enabledby entry to 'list'
+      # so that we can add a unique list of requirements to tree[i]
+      split(requires[opt] iffs[opt] enabledby[opt], r)
+      for (i in r) list[r[i]] = 1
+      for (i in list) tree[opt] = tree[opt] " " i
+   }
+
+   # print the tree for extreme debugging
+   if (deb > 2) for (i in tree) if (i != "") print i, "depends-on" tree[i]
+
+   # Ok, now check all options marked explicitly 'on' or 'off':
+   #
+   # If an option[opt] is 'on' then turn on all requires[opt]
+   # If an option[opt] is 'off' then turn off all enabledby[opt]
+   #
+   # Error out if we have to turn 'on' to an 'off' option or vice versa.
+   npending = 0
+   for (opt in option) if (opt != "") {
+      if (option[opt] == "on" || option[opt] == "off") {
+         pending[++npending] = opt
+      }
+   }
+
+   err = 0 # set on error
+   while (npending > 0) {
+      opt = pending[npending--]
+      if (option[opt] == "on") {
+         nreqs = split(requires[opt], r)
+         for (j=1; j<=nreqs; ++j) {
+            if (option[r[j]] == "off") {
+               print "option", opt, "turned on, but requirement", r[j], "is turned off"
+               err = 1
+            } else if (option[r[j]] != "on") {
+               option[r[j]] = "on"
+               pending[++npending] = r[j]
+            }
+         }
+      } else {
+         if (option[opt] != "off") {
+            print "internal error (2)"
+            exit 1
+         }
+         nreqs = split(enabledby[opt], r)
+         for (j=1; j<=nreqs; ++j) {
+            if (option[r[j]] == "on") {
+               print "option", opt, "turned off, but enabled by", r[j], "which is turned on"
+               err = 1
+            } else if (option[r[j]] != "off") {
+               option[r[j]] = "off"
+               pending[++npending] = r[j]
+            }
+         }
+      }
+   }
+   if (err) exit 1
+
+   # Sort options:
+   print "PNG_DFN_START_SORT 2" >out
+
+   # option[i] is now the complete list of all the tokens we may
+   # need to output, go through it as above, depth first.
+   finished = 0
+   while (!finished) {
+      finished = 1
+      movement = 0 # done nothing
+      for (i in option) if (!done[i]) {
+         nreqs = split(tree[i], r)
+         if (nreqs > 0) {
+            for (j=1; j<=nreqs; ++j) if (!done[r[j]]) {
+               break
+            }
+            if (j<=nreqs) {
+               finished = 0
+               continue  # next option
+            }
+         }
+
+         # All the requirements have been processed, output
+         # this option.  An option is _SUPPORTED if:
+         #
+         # all 'requires' are _SUPPORTED AND
+         # at least one of the 'if' options are _SUPPORTED AND
+         # EITHER:
+         #   The name is _SUPPORTED (on the command line)
+         # OR:
+         #   an 'enabledby' is _SUPPORTED
+         # OR:
+         #   NO_name is not defined AND
+         #   the option is not disabled; an option is disabled if:
+         #    option == off
+         #    option == disabled && everything != on
+         #    option == "" && everything == off
+         if (deb) print "option", i
+         print "" >out
+         print "/* option:", i, option[i] >out
+         print " *   requires:  " requires[i] >out
+         print " *   if:        " iffs[i] >out
+         print " *   enabled-by:" enabledby[i] >out
+         print " *   sets:      " sets[i], "*/" >out
+         print "#undef PNG_on" >out
+         print "#define PNG_on 1" >out
+
+         # requires
+         nreqs = split(requires[i], r)
+         for (j=1; j<=nreqs; ++j) {
+            print "#ifndef PNG_" r[j] "_SUPPORTED" >out
+            print "#   undef PNG_on /*!" r[j] "*/" >out
+            # This error appears in the final output if something
+            # was switched 'on' but the processing above to force
+            # the requires did not work
+            if (option[i] == "on") {
+               print error, i, "requires", r[j] end >out
+            }
+            print "#endif" >out
+         }
+
+         # if
+         have_ifs = 0
+         nreqs = split(iffs[i], r)
+         print "#undef PNG_no_if" >out
+         if (nreqs > 0) {
+            have_ifs = 1
+            print "/* if" iffs[i], "*/" >out
+            print "#define PNG_no_if 1" >out
+            for (j=1; j<=nreqs; ++j) {
+               print "#ifdef PNG_" r[j] "_SUPPORTED" >out
+               print "#   undef PNG_no_if /*" r[j] "*/" >out
+               print "#endif" >out
+            }
+            print "#ifdef PNG_no_if /*missing if*/" >out
+            print "#   undef PNG_on" >out
+            # There is no checking above for this, because we
+            # don't know which 'if' to choose, so whine about
+            # it here:
+            if (option[i] == "on") {
+               print error, i, "needs one of:", iffs[i] end >out
+            }
+            print "#endif" >out
+         }
+
+         print "#ifdef PNG_on /*requires, if*/" >out
+         # enables
+         print "#   undef PNG_not_enabled" >out
+         print "#   define PNG_not_enabled 1" >out
+         print "   /* enabled by" enabledby[i], "*/" >out
+         nreqs = split(enabledby[i], r)
+         for (j=1; j<=nreqs; ++j) {
+            print "#ifdef PNG_" r[j] "_SUPPORTED" >out
+            print "#   undef PNG_not_enabled /*" r[j] "*/" >out
+            # Oops, probably not intended (should be factored
+            # out by the checks above).
+            if (option[i] == "off") {
+               print error, i, "enabled by:", r[j] end >out
+            }
+            print "#endif" >out
+         }
+
+         print "#   ifndef PNG_" i "_SUPPORTED /*!command line*/" >out
+         print "#    ifdef PNG_not_enabled /*!enabled*/" >out
+         # 'have_ifs' here means that everything = "off" still allows an 'if' on
+         # an otherwise enabled option to turn it on; otherwise the 'if'
+         # handling is effectively disabled by 'everything = off'
+         if (option[i] == "off" || option[i] == "disabled" && everything != "on" || option[i] == "enabled" && everything == "off" && !have_ifs) {
+            print "#      undef PNG_on /*default off*/" >out
+         } else {
+            print "#      ifdef PNG_NO_" i >out
+            print "#       undef PNG_on /*turned off*/" >out
+            print "#      endif" >out
+            print "#      ifdef PNG_NO_" i "_SUPPORTED" >out
+            print "#       undef PNG_on /*turned off*/" >out
+            print "#      endif" >out
+         }
+         print "#    endif /*!enabled*/" >out
+         print "#    ifdef PNG_on" >out
+         # The _SUPPORTED macro must be defined so that dependent
+         # options output later work.
+         print "#      define PNG_" i "_SUPPORTED" >out
+         print "#    endif" >out
+         print "#   endif /*!command line*/" >out
+         # If PNG_on is still set the option should be defined in
+         # pnglibconf.h
+         print "#   ifdef PNG_on" >out
+         if (i ~ /^fail_/) {
+            print error, i, "is on: enabled by:" iffs[i] enabledby[i] ", requires" requires[i] end >out
+         } else if (i !~ /^ok_/) {
+            print def i sup >out
+            # Supported option, set required settings
+            nreqs = split(sets[i], r)
+            for (j=1; j<=nreqs; ++j) {
+               print "#    ifdef PNG_set_" r[j] >out
+               # Some other option has already set a value:
+               print error, i, "sets", r[j] ": duplicate setting" end >out
+               print error, "   previous value: " end "PNG_set_" r[j] >out
+               print "#    else" >out
+               # Else set the default: note that this won't accept arbitrary
+               # values, the setval string must be acceptable to all the C
+               # compilers we use.  That means it must be VERY simple; a number,
+               # a name or a string.
+               print "#     define PNG_set_" r[j], setval[i " " r[j]] >out
+               print "#    endif" >out
+            }
+         }
+         print "#   endif /* definition */" >out
+         print "#endif /*requires, if*/" >out
+         if (logunsupported || i ~ /^ok_/) {
+            print "#ifndef  PNG_on" >out
+            if (logunsupported) {
+               print und i une >out
+            }
+            if (i ~ /^ok_/) {
+               print error, i, "not enabled: requires:" requires[i] ", enabled by:" iffs[i] enabledby[i] end >out
+            }
+            print "#endif" >out
+         }
+
+         done[i] = 1
+         ++movement
+      }
+
+      if (!finished && !movement) {
+         print "option: loop or missing option in dependency tree, cannot process:"
+         for (i in option) if (!done[i]) {
+            print "  option", i, "depends on" tree[i], "needs:"
+            nreqs = split(tree[i], r)
+            if (nreqs > 0) for (j=1; j<=nreqs; ++j) if (!done[r[j]]) {
+               print "   " r[j]
+            }
+         }
+         exit 1
+      }
+   }
+   print "PNG_DFN_END_SORT" >out
+   print comment, "end of options", cend >out
+
+   # Do the 'setting' values second, the algorithm the standard
+   # tree walk (O(1)) done in an O(2) while/for loop; iterations
+   # settings x depth, outputting the deepest required macros
+   # first.
+   print "" >out
+   print "/* SETTINGS */" >out
+   print comment, "settings", cend >out
+   # Sort (in dfn.awk) on field 2, the setting name
+   print "PNG_DFN_START_SORT 2" >out
+   finished = 0
+   while (!finished) {
+      finished = 1
+      movement = 0 # done nothing
+      for (i in setting) if (!doneset[i]) {
+         nreqs = split(setting[i], r)
+         if (nreqs > 0) {
+            # By default assume the requires values are options, but if there
+            # is no option with that name check for a setting
+            for (j=1; j<=nreqs; ++j) if (option[r[j]] == "" && !doneset[r[j]]) {
+               break
+            }
+            if (j<=nreqs) {
+               finished = 0
+               continue # try a different setting
+            }
+         }
+
+         # All the requirements have been processed, output
+         # this setting.
+         if (deb) print "setting", i
+         deflt = defaults[i]
+         # Remove any spurious trailing spaces
+         sub(/ *$/,"",deflt)
+         # A leading @ means leave it unquoted so the preprocessor
+         # can substitute the build time value
+         if (deflt ~ /^ @/)
+            deflt = " " subs substr(deflt, 3) sube
+         print "" >out
+         print "/* setting: ", i >out
+         print " *   requires:" setting[i] >out
+         print " *   default: ", defaults[i] deflt, "*/" >out
+         for (j=1; j<=nreqs; ++j) {
+            if (option[r[j]] != "")
+               print "#ifndef PNG_" r[j] "_SUPPORTED" >out
+            else
+               print "#ifndef PNG_" r[j] >out
+            print error, i, "requires", r[j] end >out
+            print "# endif" >out
+         }
+         # The precedence is:
+         #
+         #  1) External definition; trumps:
+         #  2) Option 'sets' value; trumps:
+         #  3) Setting 'default'
+         #
+         print "#ifdef PNG_" i >out
+         # PNG_<i> is defined, so substitute the value:
+         print def i, subs "PNG_" i sube end >out
+         print "#else /* use default */" >out
+         print "# ifdef PNG_set_" i >out
+         # Value from an option 'sets' argument
+         print def i, subs "PNG_set_" i sube end >out
+         # This is so that subsequent tests on the setting work:
+         print "#  define PNG_" i, "1" >out
+         if (defaults[i] != "") {
+            print "# else /*default*/" >out
+            print def i deflt end >out
+            print "#  define PNG_" i, "1" >out
+         }
+         print "# endif /* defaults */" >out
+         print "#endif /* setting", i, "*/" >out
+
+         doneset[i] = 1
+         ++movement
+      }
+
+      if (!finished && !movement) {
+         print "setting: loop or missing setting in 'requires', cannot process:"
+         for (i in setting) if (!doneset[i]) {
+            print "  setting", i, "requires" setting[i]
+         }
+         exit 1
+      }
+   }
+   print "PNG_DFN_END_SORT" >out
+   print comment, "end of settings", cend >out
+
+   # Regular end - everything looks ok
+   if (protect != "") {
+      print start "#endif", "/*", protect, "*/" end >out
+   }
+}
diff --git a/extern/libpng/scripts/pnglibconf.dfa b/extern/libpng/scripts/pnglibconf.dfa
new file mode 100644
index 0000000000..4dcaf7c86a
--- /dev/null
+++ b/extern/libpng/scripts/pnglibconf.dfa
@@ -0,0 +1,920 @@
+# scripts/pnglibconf.dfa - library build configuration control
+#
+@/*- pnglibconf.dfn intermediate file
+@ *  generated from scripts/pnglibconf.dfa
+@ */
+#
+com pnglibconf.h - library build configuration
+com
+version
+com
+com Copyright (c) 2018-2019 Cosmin Truta
+com Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+com
+com This code is released under the libpng license.
+com For conditions of distribution and use, see the disclaimer
+com and license in png.h
+com
+
+file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H
+
+# This file is preprocessed by scripts/options.awk and the
+# C compiler to generate 'pnglibconf.h' - a list of all the
+# configuration options.  The file lists the various options
+# that can *only* be specified during the libpng build;
+# pnglibconf.h freezes the definitions selected for the specific
+# build.
+#
+# The syntax is detailed in scripts/options.awk; this is a summary
+# only:
+#
+# setting <name> [requires ...] [default]
+#    #define PNG_<name> <value>  /* value comes from current setting */
+# option <name> [requires ...] [if ...] [enables ...] [disabled]
+#    #define PNG_<name>_SUPPORTED if the requirements are met and
+#    enable the other options listed
+# chunk <name> [requires ...] [enables ...] [disabled]
+#    Enable chunk processing for the given ancillary chunk; any
+#    'requires something' expands to READ_something for read and
+#    WRITE_something for write, but the enables list members are
+#    used as given (e.g. enables GAMMA just expands to that on the
+#    correspond READ_name and WRITE_name lines.)
+#
+# "," may be used to separate options on an 'option' line and is ignored; it
+# doesn't change the meaning of the line.  (NOT setting, where "," becomes
+# part of the setting!)  A comma at the end of an option line causes a
+# continuation (the next line is included in the option too.)
+#
+# Note that the 'on' and 'off' keywords, while valid on both option
+# and chunk, should not be used in this file because they force the
+# relevant options on or off.
+
+#----------------------------------------------------------------------
+
+# The following setting, option and chunk values can all be changed
+# while building libpng:
+#
+# setting: change 'setting' lines to fine tune library performance;
+#   changes to the settings don't affect the libpng API functionally
+#
+# option: change 'option' lines to remove or add capabilities from
+#   or to the library; options change the library API
+#
+# chunk: change 'chunk' lines to remove capabilities to process
+#   optional ('ancillary') chunks.  This does not prevent PNG
+#   decoding but does change the libpng API because some chunks
+#   will be ignored.
+#
+# There are three ways of disabling features, in no particular order:
+#
+# 1) Create 'pngusr.h', enter the required private build information
+# detailed below and #define PNG_NO_<option> for each option you
+# don't want in that file in that file.  You can also turn on options
+# using PNG_<option>_SUPPORTED.  When you have finished rerun
+# configure and rebuild pnglibconf.h file with -DPNG_USER_CONFIG:
+#
+#  make clean
+#  CPPFLAGS='-DPNG_USER_CONFIG' ./configure
+#  make pnglibconf.h
+#
+# pngusr.h is only used during the creation of pnglibconf.h, but it
+# is safer to ensure that -DPNG_USER_CONFIG is specified throughout
+# the build by changing the CPPFLAGS passed to the initial ./configure
+#
+# 2) Add definitions of the settings you want to change to
+# CPPFLAGS; for example:
+#
+#   -DPNG_DEFAULT_READ_MACROS=0
+#
+# (This would change the default to *not* use read macros.)  Be
+# very careful to change only settings that don't alter the API
+# because this approach bypasses the private build checking.  You
+# can also change settings from pngpriv.h (read pngpriv.h) safely
+# without API changes.  Do that in the same way.
+#
+# 3) Write a new '.dfa' file (say 'pngusr.dfa') and in this file
+# provide override values for setting entries and turn option or
+# chunk values explicitly 'on' or 'off':
+#
+#    setting FOO default VALUE
+#    option BAR [on|off]
+#
+# Then add this file to the options.awk command line (the *first*
+# one) after this file.  The make macro DFA_XTRA is provided to make
+# this easier (set it like CPPFLAGS prior to running ./configure).
+# Look at the builds below contrib/pngminim for some extreme examples
+# of how this can be used.
+#
+# Don't edit this file unless you are contributing a patch to
+# libpng and need new or modified options/settings.
+#----------------------------------------------------------------------
+
+# The following causes commented out #undef lines to be written to
+# pnglibconf.h; this can be stopped by logunsupported=0 in a later
+# file or on the command line (after pnglibconf.dfa)
+
+logunsupported = 1
+
+# The following allows the output from configure to modify the contents of
+# pnglibconf.h
+
+@#ifdef HAVE_CONFIG_H
+@#  include "config.h"
+@#endif
+
+# PNG_USER_CONFIG has to be defined on the compiler command line
+# to cause pngusr.h to be read while constructing pnglibconf.h
+#
+# If you create a private DLL you need to define the following
+# macros in the file 'pngusr.h' and set -DPNG_USER_CONFIG for
+# compilation (i.e. in CPPFLAGS.)
+# #define PNG_USER_PRIVATEBUILD \
+#     <Describes by whom and why this version of the DLL was built>
+#  e.g. #define PNG_USER_PRIVATEBUILD "Build by MyCompany for xyz reasons."
+# #define PNG_USER_DLLFNAME_POSTFIX <two-letter postfix that serve to
+#        distinguish your DLL from those of the official release. These
+#        correspond to the trailing letters that come after the version
+#        number and must match your private DLL name>
+#  e.g. // private DLL "libpng13gx.dll"
+#       #define PNG_USER_DLLFNAME_POSTFIX "gx"
+#
+# The following macros are also at your disposal if you want to complete the
+# DLL VERSIONINFO structure.
+# - PNG_USER_VERSIONINFO_COMMENTS
+# - PNG_USER_VERSIONINFO_COMPANYNAME
+# - PNG_USER_VERSIONINFO_LEGALTRADEMARKS
+
+# It is necessary to include configures definitions here so that AC_DEFINE
+# in configure.ac works in a comprehensible way
+@#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+@#  include "config.h"
+@#endif
+
+@#ifdef PNG_USER_CONFIG
+@#  include "pngusr.h"
+@#endif
+
+# This is a special fixup for the Watcom C compiler on Windows, which has
+# multiple procedure call standards.  Unless PNG_API_RULE is set explicitly
+# (i.e. if it is not defined at this point) it will be forced to '2' here when
+# using Watcom.  This indicates to the other header files that Watcom behaviour
+# is required where appropriate.
+
+@#ifdef __WATCOMC__
+@#  ifndef PNG_API_RULE
+@#     define PNG_API_RULE 2 /* Use Watcom calling conventions */
+@#  endif
+@#endif
+
+# IN DEVELOPMENT
+# These are currently experimental features; define them if you want (NOTE:
+# experimental options must be disabled before they are defined in this file!)
+
+# NONE
+
+# Note that PNG_USER_CONFIG only has an effect when building
+# pnglibconf.h
+
+setting USER_CONFIG
+setting USER_PRIVATEBUILD
+setting USER_DLLFNAME_POSTFIX
+setting USER_VERSIONINFO_COMMENTS
+setting USER_VERSIONINFO_COMPANYNAME
+setting USER_VERSIONINFO_LEGALTRADEMARKS
+
+# Record the 'API rule' used to select calling conventions on
+# those systems that support such things (see all the comments in
+# pngconf.h)
+# Changing this setting has a fundamental affect on the PNG ABI,
+# do not release shared libraries with this changed.
+
+setting API_RULE default 0
+
+# This allows a prefix to be added to the front of every API function name (and
+# therefore every symbol) by redefining all the function names with the prefix
+# at the end of pnglibconf.h.  It also turns on similar internal symbol renaming
+# by causing a similar build-time only file, pngprefix.h, to be generated.
+
+setting PREFIX
+
+# Implementation specific control of the optimizations, enabled by those
+# hardware or software options that need it (typically when run-time choices
+# must be made by the user)
+option SET_OPTION disabled
+
+# These options are specific to the ARM NEON hardware optimizations.  At present
+# these optimizations depend on GCC specific pre-processing of an assembler (.S)
+# file so they probably won't work with other compilers.
+#
+# ARM_NEON_OPT: unset: check at compile time (__ARM_NEON__ must be defined by
+#                      the compiler, typically as a result of specifying
+#                      CC="gcc -mfpu=neon".)
+#                   0: disable (even if the CPU has a NEON FPU.)
+#                   1: check at run time (via ARM_NEON_{API,CHECK})
+#                   2: switch on unconditionally (inadvisable - instead pass
+#                      -mfpu=neon to GCC in CC)
+#           When building libpng avoid using any setting other than '0'; '1' is
+#           set automatically when either 'API' or 'CHECK' are configured in,
+#           '2' should not be necessary as -mfpu=neon will achieve the same
+#           effect as well as applying NEON optimizations to the rest of the
+#           libpng code.
+#           NOTE: any setting other than '0' requires ALIGNED_MEMORY
+# ARM_NEON_API:   (PNG_ARM_NEON == 1) allow the optimization to be switched on
+#                 with png_set_option
+# ARM_NEON_CHECK: (PNG_ARM_NEON == 1) compile a run-time check to see if Neon
+#                 extensions are supported. This is poorly supported and
+#                 deprecated - use the png_set_option API.
+setting ARM_NEON_OPT
+option ARM_NEON_API disabled requires ALIGNED_MEMORY enables SET_OPTION,
+   sets ARM_NEON_OPT 1
+option ARM_NEON_CHECK disabled requires ALIGNED_MEMORY,
+   sets ARM_NEON_OPT 1
+
+# These options are specific to the PowerPC VSX hardware optimizations.
+#
+# POWERPC_VSX_OPT: unset: check at compile time (__PPC64__,__ALTIVEC__,__VSX__
+#                      must be defined by the compiler, typically as a result
+#                      of specifying
+#                      "-mvsx -maltivec" compiler flags)
+#                   0: disable (even if the CPU supports VSX.)
+#                   1: check at run time (via POWERPC_VSX_{API,CHECK})
+#                   2: switch on unconditionally (inadvisable - instead pass
+#                      -mvsx -maltivec to compiler options)
+#           When building libpng avoid using any setting other than '0'; '1' is
+#           set automatically when either 'API' or 'CHECK' are configured in,
+#           '2' should not be necessary as "-mvsx -maltivec" will achieve the same
+#           effect as well as applying VSX optimizations to the rest of the
+#           libpng code.
+# POWERPC_VSX_API:   (PNG_POWERPC_VSX == 1) allow the optimization to be switched on
+#                 with png_set_option
+# POWERPC_VSX_CHECK: (PNG_POWERPC_VSX == 1) compile a run-time check to see if VSX
+#                 extensions are supported. This is supported not for all OSes
+#                 (see contrib/powerpc/README)
+setting POWERPC_VSX_OPT
+option POWERPC_VSX_API disabled enables SET_OPTION,
+  sets POWERPC_VSX_OPT 1
+option POWERPC_VSX_CHECK disabled,
+  sets POWERPC_VSX_OPT 1
+
+
+# These settings configure the default compression level (0-9) and 'strategy';
+# strategy is as defined by the implementors of zlib. It describes the input
+# data and modifies the zlib parameters in an attempt to optimize the balance
+# between search and huffman encoding in the zlib algorithms.  The defaults are
+# the zlib.h defaults - the apparently recursive definition does not arise
+# because the name of the setting is prefixed by PNG_
+#
+# The TEXT values are the defaults when writing compressed text (all forms)
+
+# Include the zlib header so that the defaults below are known
+@#  include <zlib.h>
+
+# The '@' here means to substitute the value when pnglibconf.h is built
+setting Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
+# TODO: why aren't these Z_RLE; zlib.h says that Z_RLE, specifically, is
+# appropriate for PNG images, maybe it doesn't exist in all versions?
+setting Z_DEFAULT_STRATEGY default @Z_FILTERED
+setting Z_DEFAULT_NOFILTER_STRATEGY default @Z_DEFAULT_STRATEGY
+setting ZLIB_VERNUM default @ZLIB_VERNUM
+
+# Linkage of:
+#
+#  API:      libpng API functions
+#  CALLBACK: internal non-file-local callbacks
+#  FUNCTION: internal non-file-local functions
+#  DATA:     internal non-file-local (const) data
+setting LINKAGE_API default extern
+setting LINKAGE_CALLBACK default extern
+setting LINKAGE_FUNCTION default extern
+setting LINKAGE_DATA default extern
+
+setting TEXT_Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
+setting TEXT_Z_DEFAULT_STRATEGY default @Z_DEFAULT_STRATEGY
+
+# Default to using the read macros
+
+setting DEFAULT_READ_MACROS default 1
+
+# The alternative is to call functions to read PNG values, if
+# the functions are turned *off* the read macros must always
+# be enabled, so turning this off will actually force the
+# USE_READ_MACROS option on (see pngconf.h)
+
+option READ_INT_FUNCTIONS requires READ
+
+# The same for write  but these can only be switched off if no writing
+# is required at all - hence the use of a 'disabled', not a 'requires'.
+# If these are needed, they are enabled in the 'WRITE options' section
+# below.
+
+option WRITE_INT_FUNCTIONS disabled
+
+# Error controls
+#
+# WARNINGS: normally on, if off no warnings are generated
+# ERROR_TEXT: normally on, if off errors happen but there is no message
+# ERROR_NUMBERS: unimplemented feature, therefore disabled
+# BENIGN_ERRORS: support for just issuing warnings for recoverable errors
+#
+# BENIGN_READ_ERRORS:
+#     By default recoverable errors on read should just generate warnings,
+#     generally safe but PNG files that don't conform to the specification will
+#     be accepted if a meaningful result can be produced.
+#
+# BENIGN_WRITE_ERRORS:
+#     By default recoverable errors on write should just generate warnings,
+#     not generally safe because this allows the application to write invalid
+#     PNG files.  Applications should enable this themselves; it's useful
+#     because it means that a failure to write an ancillary chunk can often be
+#     ignored.
+
+option WARNINGS
+option ERROR_TEXT
+option ERROR_NUMBERS disabled
+
+option BENIGN_ERRORS
+option BENIGN_WRITE_ERRORS requires BENIGN_ERRORS disabled
+option BENIGN_READ_ERRORS requires BENIGN_ERRORS
+
+
+# Generic options - affect both read and write.
+
+option MNG_FEATURES
+
+# Arithmetic options, the first is the big switch that chooses between internal
+# floating and fixed point arithmetic implementations - it does not affect any
+# APIs.  The second two (the _POINT settings) switch off individual APIs.
+#
+# Prior to libpng 1.6.8 one of the API (_POINT) variants had to be selected.  At
+# 1.6.8 this restriction has been removed; the simplified API can be used
+# without enabling any of the low level fixed/floating APIs.
+
+option FLOATING_ARITHMETIC
+option FLOATING_POINT
+option FIXED_POINT
+
+# This protects us against compilers that run on a windowing system
+# and thus don't have or would rather us not use the stdio types:
+# stdin, stdout, and stderr.  The only one currently used is stderr
+# in png_error() and png_warning().  #defining PNG_NO_CONSOLE_IO will
+# prevent these from being compiled and used. #defining PNG_NO_STDIO
+# will also prevent these, plus will prevent the entire set of stdio
+# macros and functions (FILE *, printf, etc.) from being compiled and used,
+# unless (PNG_DEBUG > 0) has been #defined.
+
+option STDIO
+option CONSOLE_IO requires STDIO
+
+# Note: prior to 1.5.0 this option could not be disabled if STDIO
+# was enabled.  Prior to 1.5.3 this option required STDIO
+
+option TIME_RFC1123
+
+# PNG_SETJMP_NOT_SUPPORTED is an old equivalent for NO_SETJMP
+
+option SETJMP
+= NO_SETJMP SETJMP_NOT_SUPPORTED
+
+# If this is disabled it is not possible for apps to get the
+# values from the 'info' structure, this effectively removes
+# quite a lot of the READ API.
+
+option EASY_ACCESS
+
+# Added at libpng-1.2.0
+
+option USER_MEM
+
+# Added at libpng-1.4.0
+
+option IO_STATE
+
+# Libpng limits: limit the size of images and data on read.
+#
+# If this option is disabled all the limit checking code will be disabled:
+
+option USER_LIMITS requires READ
+
+# The default settings given below for the limits mean that libpng will
+# limit the size of images or the size of data in ancillary chunks to less
+# than the specification or implementation limits. Settings have the
+# following interpretations:
+#
+# USER_WIDTH_MAX: maximum width of an image that will be read
+# USER_HEIGHT_MAX: maximum height
+# USER_CHUNK_MALLOC_MAX: maximum in-memory (decompressed) size of a single chunk
+# USER_CHUNK_CACHE_MAX: maximum number of chunks to be cached
+#
+# Only chunks that are variable in number are counted towards the
+
+# Use 0x7fffffff for unlimited
+setting USER_WIDTH_MAX default        1000000
+setting USER_HEIGHT_MAX default       1000000
+
+# Use 0 for unlimited
+setting USER_CHUNK_CACHE_MAX default     1000
+setting USER_CHUNK_MALLOC_MAX default 8000000
+
+# If this option is enabled APIs to set the above limits at run time are added;
+# without this the hardwired (compile time) limits will be used.
+option SET_USER_LIMITS requires USER_LIMITS
+
+# All of the following options relate to code capabilities for
+# processing image data before creating a PNG or after reading one.
+# You can remove these capabilities safely and still be PNG
+# conformant, however the library that results is still non-standard.
+# See the comments above about how to change options and settings.
+
+# READ options
+#
+# WARNING: in libpng 1.5 maintained configuration compatibility with earlier
+# versions.  In some cases turning off an option turned off other options, in
+# others it was ineffective unless dependent options were also turned off.
+# Libpng 1.6 changes this: in general if you turn off an option that affects
+# APIs it stays off and simply disables APIs that depend on it.
+#
+# As a result if you simply port the libpng 1.5 configuration to libpng 1.6 you
+# will probably see build failures due to missing APIs.  Fixing these failures
+# requires some, perhaps considerable, knowledge of what your libpng using
+# applications are doing, fortunately there is no great reason for you to move
+# to libpng 1.6; the new interfaces in 1.6 will take several years to become
+# popular.
+
+option READ enables READ_INTERLACING SET_OPTION
+
+# Disabling READ_16BIT does not disable reading 16-bit PNG files, but it
+# forces them to be chopped down to 8-bit, and disables any 16-bit
+# processing after that has happened.  You need to be sure to enable
+# READ_SCALE_16_TO_8 or READ_STRIP_16_TO_8 when you disable READ_16BIT for
+# this to work properly.  You should disable the other option if you need to
+# ensure a particular conversion (otherwise the app can chose.)
+
+option READ_16BIT requires READ enables 16BIT
+
+option READ_QUANTIZE requires READ
+
+option READ_TRANSFORMS requires READ
+= NO_READ_TRANSFORMS READ_TRANSFORMS_NOT_SUPPORTED
+
+# Read gamma handling.  Gamma processing is a core part of libpng and many of
+# the capabilities are dependent on libpng performing gamma correction.
+#
+# In libpng 1.6 disabling gamma processing (setting PNG_NO_READ_GAMMA)
+# consistently disables those parts of the API that depend on it.  Prior to
+# 1.6.0 this was not true; the results were unpredictable and varied between
+# releases.
+#
+# If you disable gamma processing and your program no longer compiles you need
+# to ask whether you really need the APIs that are missing.  If you do then you
+# almost certainly need the gamma processing.
+#
+# If you handle gamma issues outside libpng then you do not need the libpng
+# gamma processing; and it is an enormous waste of space.  You just need to
+# remove the use of libpng APIs that depend on it.
+option READ_GAMMA requires READ_TRANSFORMS, READ_gAMA, READ_sRGB
+
+option READ_ALPHA_MODE requires READ_TRANSFORMS, READ_GAMMA
+option READ_BACKGROUND requires READ_TRANSFORMS, READ_STRIP_ALPHA, READ_GAMMA
+option READ_BGR requires READ_TRANSFORMS
+option READ_EXPAND_16 requires READ_TRANSFORMS, READ_16BIT, READ_EXPAND
+option READ_EXPAND requires READ_TRANSFORMS
+option READ_FILLER requires READ_TRANSFORMS
+option READ_GRAY_TO_RGB requires READ_TRANSFORMS
+option READ_INVERT_ALPHA requires READ_TRANSFORMS
+option READ_INVERT requires READ_TRANSFORMS
+option READ_PACK requires READ_TRANSFORMS
+option READ_PACKSWAP requires READ_TRANSFORMS
+option READ_RGB_TO_GRAY requires READ_TRANSFORMS, READ_GAMMA enables COLORSPACE
+option READ_SCALE_16_TO_8 requires READ_TRANSFORMS
+option READ_SHIFT requires READ_TRANSFORMS
+option READ_STRIP_16_TO_8 requires READ_TRANSFORMS
+option READ_STRIP_ALPHA requires READ_TRANSFORMS
+option READ_SWAP_ALPHA requires READ_TRANSFORMS
+option READ_SWAP requires READ_TRANSFORMS, READ_16BIT
+option READ_USER_TRANSFORM requires READ_TRANSFORMS
+
+option PROGRESSIVE_READ requires READ
+option SEQUENTIAL_READ requires READ
+
+# You can define PNG_NO_PROGRESSIVE_READ if you don't do progressive reading.
+# This is not talking about interlacing capability!  You'll still have
+# interlacing unless you turn off the following which is required
+# for PNG-compliant decoders.  (In other words, do not do this - in
+# fact it can't be disabled from the command line!)
+#option READ_INTERLACING requires READ
+
+option READ_COMPOSITE_NODIV requires READ
+= NO_READ_COMPOSITE_NODIV NO_READ_COMPOSITED_NODIV
+
+# Inch conversions
+
+option INCH_CONVERSIONS
+= INCH_CONVERSIONS INCH_CONVERSIONS
+
+# API to build a grayscale palette
+# NOTE: this is not used internally by libpng at present.
+
+option BUILD_GRAYSCALE_PALETTE
+
+# WRITE options
+
+option WRITE enables WRITE_INT_FUNCTIONS
+
+# Disabling WRITE_16BIT prevents 16-bit PNG files from being
+# generated.
+option WRITE_16BIT requires WRITE enables 16BIT
+
+option WRITE_TRANSFORMS requires WRITE
+= NO_WRITE_TRANSFORMS WRITE_TRANSFORMS_NOT_SUPPORTED
+
+option WRITE_SHIFT requires WRITE_TRANSFORMS
+option WRITE_PACK requires WRITE_TRANSFORMS
+option WRITE_BGR requires WRITE_TRANSFORMS
+option WRITE_SWAP requires WRITE_TRANSFORMS, WRITE_16BIT
+option WRITE_PACKSWAP requires WRITE_TRANSFORMS
+option WRITE_INVERT requires WRITE_TRANSFORMS
+option WRITE_FILLER requires WRITE_TRANSFORMS
+option WRITE_SWAP_ALPHA requires WRITE_TRANSFORMS
+option WRITE_INVERT_ALPHA requires WRITE_TRANSFORMS
+option WRITE_USER_TRANSFORM requires WRITE_TRANSFORMS
+
+# This is not required for PNG-compliant encoders, but can cause
+# trouble if left undefined
+
+option WRITE_INTERLACING requires WRITE
+
+# Deprecated, will be removed.
+option WRITE_WEIGHTED_FILTER requires WRITE
+
+option WRITE_FLUSH requires WRITE
+
+# Note: these can be turned off explicitly if not required by the
+# apps implementing the user transforms
+option USER_TRANSFORM_PTR if READ_USER_TRANSFORM, WRITE_USER_TRANSFORM
+option USER_TRANSFORM_INFO if READ_USER_TRANSFORM, WRITE_USER_TRANSFORM
+
+# This enables API to set compression parameters for compressing
+# non-IDAT chunks (zTXt, iTXt, iCCP, and unknown chunks).  This feature
+# was added at libpng-1.5.3.
+option WRITE_CUSTOMIZE_ZTXT_COMPRESSION requires WRITE
+option WRITE_CUSTOMIZE_COMPRESSION requires WRITE
+
+# Any chunks you are not interested in, you can undef here.  The
+# ones that allocate memory may be especially important (hIST,
+# tEXt, zTXt, tRNS, pCAL).  Others will just save time and make png_info
+# a bit smaller.
+
+# The size of the png_text structure changed in libpng-1.0.6 when
+# iTXt support was added.  iTXt support was turned off by default through
+# libpng-1.2.x, to support old apps that malloc the png_text structure
+# instead of calling png_set_text() and letting libpng malloc it.  It
+# was turned on by default in libpng-1.4.0.
+
+option READ_ANCILLARY_CHUNKS requires READ
+# PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED is deprecated.
+= NO_READ_ANCILLARY_CHUNKS READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+option WRITE_ANCILLARY_CHUNKS requires WRITE
+# PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED is deprecated.
+= NO_WRITE_ANCILLARY_CHUNKS WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+# These options disable *all* the text chunks if turned off
+
+option TEXT disabled
+option READ_TEXT requires READ_ANCILLARY_CHUNKS enables TEXT
+option WRITE_TEXT requires WRITE_ANCILLARY_CHUNKS enables TEXT
+
+# Moved to pnglibconf.h at libpng-1.5.0
+# Feature support: in 1.4 this was in pngconf.h, but the following
+# features have no affect on the libpng API.  Add library
+# only features to the end of this list.  Add features that
+# affect the API above.  (Note: the list of chunks follows
+# the library-only settings.)
+#
+# BUILD TIME ONLY OPTIONS
+#   These options do not affect the API but rather alter how the
+#   API is implemented, they get recorded in pnglibconf.h, but
+#   can't be changed by the application.
+
+# Colorspace support (enabled as required); just the support for colorant
+# information.  Gamma support, likewise, is just support for the gamma
+# information, READ_GAMMA is required for gamma transformations (so it
+# is possible to read PNG gamma without enabling all the libpng transform
+# code - do this for applications that do their own gamma processing)
+#
+# As of 1.6.0 COLORSPACE is only useful if the application processes the
+# information; this is because the library does not do any colorspace
+# processing, it just validates the data in the PNG file.
+
+option GAMMA disabled
+option COLORSPACE enables GAMMA disabled
+
+# When an ICC profile is read, or png_set, it will be checked for a match
+# against known sRGB profiles if the sRGB handling is enabled.  The
+# PNG_sRGB_PROFILE_CHECKS setting controls how much work is done during the
+# check:
+#
+# -1: Don't do any sRGB profile checking.
+#
+#  0: Just validate the profile MD5 signature if present, otherwise use
+#     the checks in option 1.
+#
+#  1: Additionally check the length, intent and adler32 checksum of the
+#     actual data.   If enabled this will reject known profiles that have
+#     had the rendering intent in the header changed as well as other edits
+#     done without updating the checksum.  See the discussion below.
+#
+#  2: Additionally checksum all the data using the ethernet CRC32 algorithm.
+#     This makes it more difficult to fake profiles and makes it less likely
+#     to get a false positive on profiles with no signature, but is probably
+#     just a waste of time since all currently approved ICC sRGB profiles have
+#     a secure MD5 signature.
+#
+# The rendering intent.  An ICC profile stores an intended rendering intent,
+# but does not include the value in the signature.  The intent is documented
+# as the intent that should be used when combining two profiles.  The sRGB
+# profile is intended, however, to be used with any of the four defined intents.
+# For this reason the sRGB chunk includes an 'intent' to be used when displaying
+# the image (intent is really a property of the image not the profile.)
+#
+# Unfortunately the iCCP chunk does not.  It may therefore be that some
+# applications modify the intent in profiles (including sRGB profiles) to work
+# round this problem.  Selecting an option other than option '0' will cause such
+# modified profiles to be rejected.
+#
+# Security.  The use of Adler32 and CRC32 checksums does not help significantly
+# with any security issues.  It is relatively easy to produce arbitrary profiles
+# with the required checksums on current computer systems.  Nevertheless
+# security does not seem to be an issue because the only consequence of a false
+# positive is a false assertion that the profile is an sRGB profile.  This might
+# be used to hide data from libpng using applications, but it doesn't seem
+# possible to damage them.
+
+setting sRGB_PROFILE_CHECKS default 2
+
+# Artificially align memory - the code typically aligns to 8 byte
+# boundaries if this is switched on, it's a small waste of space
+# but can help (in theory) on some architectures.  Only affects
+# internal structures.  Added at libpng 1.4.0
+
+option ALIGNED_MEMORY
+
+# Buggy compilers (e.g., gcc 2.7.2.2) need PNG_NO_POINTER_INDEXING
+# See png[wr]util.c, normally this should always be *on*
+
+option POINTER_INDEXING
+
+# Other defines for things like memory and the like can go here.
+
+# BUILD TIME SETTINGS
+# Like build time options these do not affect the API, but they
+# may be useful to applications because they record details of
+# how the API will behave particularly with regard to overall
+# accuracy.
+
+# This controls how fine the quantizing gets.  As this allocates
+# a largish chunk of memory (32K), those who are not as concerned
+# with quantizing quality can decrease some or all of these.
+
+setting QUANTIZE_RED_BITS default 5
+setting QUANTIZE_GREEN_BITS default 5
+setting QUANTIZE_BLUE_BITS default 5
+
+# This controls how fine the gamma correction becomes when you
+# are only interested in 8 bits anyway.  Increasing this value
+# results in more memory being used, and more pow() functions
+# being called to fill in the gamma tables.  Don't set this value
+# less than 8, and even that may not work (I haven't tested it).
+
+setting MAX_GAMMA_8 default 11
+
+# This controls how much a difference in gamma we can tolerate before
+# we actually start doing gamma conversion, it's a fixed point value,
+# so the default below is 0.05, meaning libpng ignores corrections in
+# the range 0.95 to 1.05
+
+setting GAMMA_THRESHOLD_FIXED default 5000
+
+# Precision to use when converting a floating point value to a PNG
+# extension format string in an sCAL chunk (only relevant if the
+# floating point API is enabled)
+
+setting sCAL_PRECISION default 5
+
+# This is the size of the compression buffer, and thus the size of
+# an IDAT chunk.  Make this whatever size you feel is best for your
+# machine.  One of these will be allocated per png_struct.  When this
+# is full, it writes the data to the disk, and does some other
+# calculations.  Making this an extremely small size may slow
+# the library down, but you may want to experiment to determine
+# where it becomes significant, if you are concerned with memory
+# usage.  Note that zlib allocates at least 32Kb also.  For readers,
+# this describes the size of the buffer available to read the data in.
+# Unless this gets smaller than the size of a row (compressed),
+# it should not make much difference how big this is.
+
+setting ZBUF_SIZE default 8192
+
+# This is the size of the decompression buffer used when counting or checking
+# the decompressed size of an LZ stream from a compressed ancillary chunk; the
+# decompressed data is never used so a different size may be optimal.  This size
+# was determined using contrib/libtests/timepng.c with compressed zTXt data
+# around 11MByte in size.  Slight speed improvements (up to about 14% in
+# timepng) can be achieved by very large increases (to 32kbyte) on regular data,
+# but highly compressible data shows only around 2% improvement.   The size is
+# chosen to minimize the effects of DoS attacks based on using very large
+# amounts of highly compressible data.
+
+setting INFLATE_BUF_SIZE default 1024
+
+# This is the maximum amount of IDAT data that the sequential reader will
+# process at one time.  The setting does not affect the size of IDAT chunks
+# read, just the amount read at once.  Neither does it affect the progressive
+# reader, which processes just the amount of data the application gives it.
+# The sequential reader is currently unable to process more than one IDAT at
+# once - it has to read and process each one in turn.  There is no point setting
+# this to a value larger than the IDAT chunks typically encountered (it would
+# just waste memory) but there may be some point in reducing it below the value
+# of ZBUF_SIZE (the size of IDAT chunks written by libpng.)
+
+setting IDAT_READ_SIZE default PNG_ZBUF_SIZE
+
+# Ancillary chunks
+chunk bKGD
+chunk cHRM enables COLORSPACE
+chunk eXIf
+chunk gAMA enables GAMMA
+chunk hIST
+chunk iCCP enables COLORSPACE, GAMMA
+chunk iTXt enables TEXT
+chunk oFFs
+chunk pCAL
+chunk pHYs
+chunk sBIT
+chunk sCAL
+chunk sPLT
+chunk sRGB enables COLORSPACE, GAMMA, SET_OPTION
+chunk tEXt requires TEXT
+chunk tIME
+chunk tRNS
+chunk zTXt enables TEXT
+
+# This only affects support of the optional PLTE chunk in RGB and RGBA
+# images.  Notice that READ_ANCILLARY_CHUNKS therefore disables part
+# of the regular chunk reading too.
+
+option READ_OPT_PLTE requires READ_ANCILLARY_CHUNKS
+
+# Unknown chunk handling
+#
+# 'UNKNOWN_CHUNKS' is a global option to disable all unknown chunk handling on
+# read or write; everything else below requires it (directly or indirectly).
+option UNKNOWN_CHUNKS
+
+# There are three main options to control the ability to read and write unknown
+# chunks.  If either read option is turned on then unknown chunks will be read,
+# otherwise they are skipped.  If the write option is turned on unknown chunks
+# set by png_set_unknown_chunks will be written otherwise it is an error to call
+# that API on a write struct.
+option WRITE_UNKNOWN_CHUNKS requires WRITE requires UNKNOWN_CHUNKS
+option WRITE_UNKNOWN_CHUNKS enables STORE_UNKNOWN_CHUNKS
+
+# The first way to read user chunks is to have libpng save them for a later call
+# to png_get_unknown_chunks, the application must call
+# png_set_keep_unknown_chunks to cause this to actually happen (see png.h)
+option SAVE_UNKNOWN_CHUNKS requires READ requires SET_UNKNOWN_CHUNKS
+option SAVE_UNKNOWN_CHUNKS enables READ_UNKNOWN_CHUNKS, STORE_UNKNOWN_CHUNKS
+
+# The second approach is to use an application provided callback to process the
+# chunks, the callback can either handle the chunk entirely itself or request
+# that libpng store the chunk for later retrieval via png_get_unknown_chunks.
+#
+# NOTE: If STORE_UNKNOWN_CHUNKS is not enabled (which is the default if
+# both SAVE_UNKNOWN_CHUNKS and WRITE_UNKNOWN_CHUNKS are disabled) then a
+# 0 result from the callback will be ignored because no support for saving
+# unknown chunks has been compiled in.  The normal symptom is that your app
+# fails to compile because png_get_unknown_chunks is no longer defined in png.h.
+# If you encounter this issue simply enable STORE_UNKNOWN_CHUNKS in your build.
+#
+# Note that there is no 'WRITE_USER_CHUNKS' so the USER_CHUNKS option is always
+# the same as READ_USER_CHUNKS at present
+option READ_USER_CHUNKS requires READ, UNKNOWN_CHUNKS
+option READ_USER_CHUNKS enables READ_UNKNOWN_CHUNKS, USER_CHUNKS
+
+# Two further options are provided to allow detailed control of the handling.
+# The first enables png_set_keep_unknown_chunks; this allows the default to be
+# changed from discarding unknown chunks and allows per-chunk control.  This is
+# required to use the SAVE_UNKNOWN_CHUNKS option.  If enabled this option also
+# applies to write (see png.h), otherwise the write API simply writes all the
+# chunks it is given.
+#
+# The second option extends the unknown handling to allow known chunks to be
+# handled as though they were unknown.  This option doesn't change any APIs, it
+# merely turns on the code to check known as well as unknown chunks.
+#
+# This option no longer affects the write code.  It can be safely disabled and
+# will prevent applications stopping libpng reading known chunks.
+option SET_UNKNOWN_CHUNKS requires UNKNOWN_CHUNKS
+option HANDLE_AS_UNKNOWN requires SET_UNKNOWN_CHUNKS
+
+# The following options are derived from the above and should not be turned on
+# explicitly.
+option READ_UNKNOWN_CHUNKS requires UNKNOWN_CHUNKS disabled
+option STORE_UNKNOWN_CHUNKS requires UNKNOWN_CHUNKS disabled
+
+option CONVERT_tIME requires WRITE_ANCILLARY_CHUNKS
+# The "tm" structure is not supported on WindowsCE
+
+@#ifdef _WIN32_WCE
+@#   define PNG_NO_CONVERT_tIME
+@#endif
+
+option WRITE_FILTER requires WRITE
+
+option SAVE_INT_32 disabled
+# png_save_int_32 is required internally for writing the ancillary chunks oFFs
+# and pCAL and for both reading and writing iCCP (for the generation/checking of
+# the corresponding cHRM/gAMA chunks) if full ICC is supported.
+
+# added at libpng-1.5.4
+
+option WRITE_OPTIMIZE_CMF requires WRITE
+
+option READ_COMPRESSED_TEXT disabled
+option READ_iCCP enables READ_COMPRESSED_TEXT
+option READ_iTXt enables READ_COMPRESSED_TEXT
+option READ_zTXt enables READ_COMPRESSED_TEXT
+
+option WRITE_oFFs enables SAVE_INT_32
+option WRITE_pCAL enables SAVE_INT_32
+option WRITE_cHRM enables SAVE_INT_32
+
+option WRITE_COMPRESSED_TEXT disabled
+option WRITE_iCCP enables WRITE_COMPRESSED_TEXT
+option WRITE_iTXt enables WRITE_COMPRESSED_TEXT
+option WRITE_zTXt enables WRITE_COMPRESSED_TEXT
+
+# Turn this off to disable png_read_png() and png_write_png() and
+# leave the row_pointers member out of the info structure.
+
+option INFO_IMAGE
+
+# added at libpng-1.5.10
+# Turn this off to disable warning about invalid palette index and
+# leave the num_palette_max member out of the png structure.
+
+option CHECK_FOR_INVALID_INDEX enables READ_CHECK_FOR_INVALID_INDEX
+option CHECK_FOR_INVALID_INDEX enables WRITE_CHECK_FOR_INVALID_INDEX
+option READ_CHECK_FOR_INVALID_INDEX requires READ, CHECK_FOR_INVALID_INDEX
+option WRITE_CHECK_FOR_INVALID_INDEX requires WRITE, CHECK_FOR_INVALID_INDEX
+
+# added at libpng-1.5.15
+option GET_PALETTE_MAX enables READ_GET_PALETTE_MAX WRITE_GET_PALETTE_MAX
+option READ_GET_PALETTE_MAX requires READ_CHECK_FOR_INVALID_INDEX disabled
+option WRITE_GET_PALETTE_MAX requires WRITE_CHECK_FOR_INVALID_INDEX disabled
+
+# Simplified API options (added at libpng-1.6.0)
+#  In libpng 1.6.8 the handling of these options was changed to used 'requires'
+#  throughout, so that disabling some of the low level support always disables
+#  the base simplified read/write API.  This much simplifies the handling and
+#  makes 'everything = off' work in a more intuitive way.  It eliminates a
+#  previously reported feature that APIs previously enabled by the simplified
+#  API couldn't be turned off without explicitly turning off the simplified
+#  APIs.
+#
+# Read:
+option SIMPLIFIED_READ,
+   requires SEQUENTIAL_READ, READ_TRANSFORMS, SETJMP, BENIGN_ERRORS,
+      READ_EXPAND, READ_16BIT, READ_EXPAND_16, READ_SCALE_16_TO_8,
+      READ_RGB_TO_GRAY, READ_ALPHA_MODE, READ_BACKGROUND, READ_STRIP_ALPHA,
+      READ_FILLER, READ_SWAP, READ_PACK, READ_GRAY_TO_RGB, READ_GAMMA,
+      READ_tRNS, READ_bKGD, READ_gAMA, READ_cHRM, READ_sRGB, READ_sBIT
+
+# AFIRST and BGR read options:
+#  Prior to libpng 1.6.8 these were disabled but switched on if the low level
+#  libpng routines that do the swaps were enabled.  This worked but was
+#  confusing.  In libpng 1.6.8 the options were changed to simple 'requires'
+#  and are enabled by default.  This should work the same way in practice.
+option SIMPLIFIED_READ_AFIRST enables FORMAT_AFIRST,
+   requires SIMPLIFIED_READ READ_SWAP_ALPHA
+
+option SIMPLIFIED_READ_BGR enables FORMAT_BGR,
+   requires SIMPLIFIED_READ READ_BGR
+
+# Write:
+option SIMPLIFIED_WRITE,
+   requires WRITE, SETJMP, WRITE_SWAP, WRITE_PACK,
+      WRITE_tRNS, WRITE_gAMA, WRITE_sRGB, WRITE_cHRM
+
+# 1.6.22: allow simplified write without stdio support:
+option SIMPLIFIED_WRITE_STDIO requires SIMPLIFIED_WRITE STDIO
+
+option SIMPLIFIED_WRITE_AFIRST enables FORMAT_AFIRST,
+   requires SIMPLIFIED_WRITE WRITE_SWAP_ALPHA
+
+option SIMPLIFIED_WRITE_BGR enables FORMAT_BGR,
+   requires SIMPLIFIED_WRITE WRITE_BGR
+
+# Formats:
+option FORMAT_AFIRST disabled
+option FORMAT_BGR disabled
diff --git a/extern/libpng/scripts/pnglibconf.h.prebuilt b/extern/libpng/scripts/pnglibconf.h.prebuilt
new file mode 100644
index 0000000000..e1e27e957e
--- /dev/null
+++ b/extern/libpng/scripts/pnglibconf.h.prebuilt
@@ -0,0 +1,219 @@
+/* pnglibconf.h - library build configuration */
+
+/* libpng version 1.6.37 */
+
+/* Copyright (c) 2018-2019 Cosmin Truta */
+/* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson */
+
+/* This code is released under the libpng license. */
+/* For conditions of distribution and use, see the disclaimer */
+/* and license in png.h */
+
+/* pnglibconf.h */
+/* Machine generated file: DO NOT EDIT */
+/* Derived from: scripts/pnglibconf.dfa */
+#ifndef PNGLCONF_H
+#define PNGLCONF_H
+/* options */
+#define PNG_16BIT_SUPPORTED
+#define PNG_ALIGNED_MEMORY_SUPPORTED
+/*#undef PNG_ARM_NEON_API_SUPPORTED*/
+/*#undef PNG_ARM_NEON_CHECK_SUPPORTED*/
+#define PNG_BENIGN_ERRORS_SUPPORTED
+#define PNG_BENIGN_READ_ERRORS_SUPPORTED
+/*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/
+#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+#define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_COLORSPACE_SUPPORTED
+#define PNG_CONSOLE_IO_SUPPORTED
+#define PNG_CONVERT_tIME_SUPPORTED
+#define PNG_EASY_ACCESS_SUPPORTED
+/*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
+#define PNG_ERROR_TEXT_SUPPORTED
+#define PNG_FIXED_POINT_SUPPORTED
+#define PNG_FLOATING_ARITHMETIC_SUPPORTED
+#define PNG_FLOATING_POINT_SUPPORTED
+#define PNG_FORMAT_AFIRST_SUPPORTED
+#define PNG_FORMAT_BGR_SUPPORTED
+#define PNG_GAMMA_SUPPORTED
+#define PNG_GET_PALETTE_MAX_SUPPORTED
+#define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#define PNG_INCH_CONVERSIONS_SUPPORTED
+#define PNG_INFO_IMAGE_SUPPORTED
+#define PNG_IO_STATE_SUPPORTED
+#define PNG_MNG_FEATURES_SUPPORTED
+#define PNG_POINTER_INDEXING_SUPPORTED
+/*#undef PNG_POWERPC_VSX_API_SUPPORTED*/
+/*#undef PNG_POWERPC_VSX_CHECK_SUPPORTED*/
+#define PNG_PROGRESSIVE_READ_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+#define PNG_READ_ALPHA_MODE_SUPPORTED
+#define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
+#define PNG_READ_BACKGROUND_SUPPORTED
+#define PNG_READ_BGR_SUPPORTED
+#define PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_READ_COMPOSITE_NODIV_SUPPORTED
+#define PNG_READ_COMPRESSED_TEXT_SUPPORTED
+#define PNG_READ_EXPAND_16_SUPPORTED
+#define PNG_READ_EXPAND_SUPPORTED
+#define PNG_READ_FILLER_SUPPORTED
+#define PNG_READ_GAMMA_SUPPORTED
+#define PNG_READ_GET_PALETTE_MAX_SUPPORTED
+#define PNG_READ_GRAY_TO_RGB_SUPPORTED
+#define PNG_READ_INTERLACING_SUPPORTED
+#define PNG_READ_INT_FUNCTIONS_SUPPORTED
+#define PNG_READ_INVERT_ALPHA_SUPPORTED
+#define PNG_READ_INVERT_SUPPORTED
+#define PNG_READ_OPT_PLTE_SUPPORTED
+#define PNG_READ_PACKSWAP_SUPPORTED
+#define PNG_READ_PACK_SUPPORTED
+#define PNG_READ_QUANTIZE_SUPPORTED
+#define PNG_READ_RGB_TO_GRAY_SUPPORTED
+#define PNG_READ_SCALE_16_TO_8_SUPPORTED
+#define PNG_READ_SHIFT_SUPPORTED
+#define PNG_READ_STRIP_16_TO_8_SUPPORTED
+#define PNG_READ_STRIP_ALPHA_SUPPORTED
+#define PNG_READ_SUPPORTED
+#define PNG_READ_SWAP_ALPHA_SUPPORTED
+#define PNG_READ_SWAP_SUPPORTED
+#define PNG_READ_TEXT_SUPPORTED
+#define PNG_READ_TRANSFORMS_SUPPORTED
+#define PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_READ_USER_CHUNKS_SUPPORTED
+#define PNG_READ_USER_TRANSFORM_SUPPORTED
+#define PNG_READ_bKGD_SUPPORTED
+#define PNG_READ_cHRM_SUPPORTED
+#define PNG_READ_eXIf_SUPPORTED
+#define PNG_READ_gAMA_SUPPORTED
+#define PNG_READ_hIST_SUPPORTED
+#define PNG_READ_iCCP_SUPPORTED
+#define PNG_READ_iTXt_SUPPORTED
+#define PNG_READ_oFFs_SUPPORTED
+#define PNG_READ_pCAL_SUPPORTED
+#define PNG_READ_pHYs_SUPPORTED
+#define PNG_READ_sBIT_SUPPORTED
+#define PNG_READ_sCAL_SUPPORTED
+#define PNG_READ_sPLT_SUPPORTED
+#define PNG_READ_sRGB_SUPPORTED
+#define PNG_READ_tEXt_SUPPORTED
+#define PNG_READ_tIME_SUPPORTED
+#define PNG_READ_tRNS_SUPPORTED
+#define PNG_READ_zTXt_SUPPORTED
+#define PNG_SAVE_INT_32_SUPPORTED
+#define PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_SEQUENTIAL_READ_SUPPORTED
+#define PNG_SETJMP_SUPPORTED
+#define PNG_SET_OPTION_SUPPORTED
+#define PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_SET_USER_LIMITS_SUPPORTED
+#define PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
+#define PNG_SIMPLIFIED_READ_BGR_SUPPORTED
+#define PNG_SIMPLIFIED_READ_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_SUPPORTED
+#define PNG_STDIO_SUPPORTED
+#define PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_TEXT_SUPPORTED
+#define PNG_TIME_RFC1123_SUPPORTED
+#define PNG_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_USER_CHUNKS_SUPPORTED
+#define PNG_USER_LIMITS_SUPPORTED
+#define PNG_USER_MEM_SUPPORTED
+#define PNG_USER_TRANSFORM_INFO_SUPPORTED
+#define PNG_USER_TRANSFORM_PTR_SUPPORTED
+#define PNG_WARNINGS_SUPPORTED
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED
+#define PNG_WRITE_BGR_SUPPORTED
+#define PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#define PNG_WRITE_FILLER_SUPPORTED
+#define PNG_WRITE_FILTER_SUPPORTED
+#define PNG_WRITE_FLUSH_SUPPORTED
+#define PNG_WRITE_GET_PALETTE_MAX_SUPPORTED
+#define PNG_WRITE_INTERLACING_SUPPORTED
+#define PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+#define PNG_WRITE_INVERT_ALPHA_SUPPORTED
+#define PNG_WRITE_INVERT_SUPPORTED
+#define PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+#define PNG_WRITE_PACKSWAP_SUPPORTED
+#define PNG_WRITE_PACK_SUPPORTED
+#define PNG_WRITE_SHIFT_SUPPORTED
+#define PNG_WRITE_SUPPORTED
+#define PNG_WRITE_SWAP_ALPHA_SUPPORTED
+#define PNG_WRITE_SWAP_SUPPORTED
+#define PNG_WRITE_TEXT_SUPPORTED
+#define PNG_WRITE_TRANSFORMS_SUPPORTED
+#define PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_WRITE_USER_TRANSFORM_SUPPORTED
+#define PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+#define PNG_WRITE_bKGD_SUPPORTED
+#define PNG_WRITE_cHRM_SUPPORTED
+#define PNG_WRITE_eXIf_SUPPORTED
+#define PNG_WRITE_gAMA_SUPPORTED
+#define PNG_WRITE_hIST_SUPPORTED
+#define PNG_WRITE_iCCP_SUPPORTED
+#define PNG_WRITE_iTXt_SUPPORTED
+#define PNG_WRITE_oFFs_SUPPORTED
+#define PNG_WRITE_pCAL_SUPPORTED
+#define PNG_WRITE_pHYs_SUPPORTED
+#define PNG_WRITE_sBIT_SUPPORTED
+#define PNG_WRITE_sCAL_SUPPORTED
+#define PNG_WRITE_sPLT_SUPPORTED
+#define PNG_WRITE_sRGB_SUPPORTED
+#define PNG_WRITE_tEXt_SUPPORTED
+#define PNG_WRITE_tIME_SUPPORTED
+#define PNG_WRITE_tRNS_SUPPORTED
+#define PNG_WRITE_zTXt_SUPPORTED
+#define PNG_bKGD_SUPPORTED
+#define PNG_cHRM_SUPPORTED
+#define PNG_eXIf_SUPPORTED
+#define PNG_gAMA_SUPPORTED
+#define PNG_hIST_SUPPORTED
+#define PNG_iCCP_SUPPORTED
+#define PNG_iTXt_SUPPORTED
+#define PNG_oFFs_SUPPORTED
+#define PNG_pCAL_SUPPORTED
+#define PNG_pHYs_SUPPORTED
+#define PNG_sBIT_SUPPORTED
+#define PNG_sCAL_SUPPORTED
+#define PNG_sPLT_SUPPORTED
+#define PNG_sRGB_SUPPORTED
+#define PNG_tEXt_SUPPORTED
+#define PNG_tIME_SUPPORTED
+#define PNG_tRNS_SUPPORTED
+#define PNG_zTXt_SUPPORTED
+/* end of options */
+/* settings */
+#define PNG_API_RULE 0
+#define PNG_DEFAULT_READ_MACROS 1
+#define PNG_GAMMA_THRESHOLD_FIXED 5000
+#define PNG_IDAT_READ_SIZE PNG_ZBUF_SIZE
+#define PNG_INFLATE_BUF_SIZE 1024
+#define PNG_LINKAGE_API extern
+#define PNG_LINKAGE_CALLBACK extern
+#define PNG_LINKAGE_DATA extern
+#define PNG_LINKAGE_FUNCTION extern
+#define PNG_MAX_GAMMA_8 11
+#define PNG_QUANTIZE_BLUE_BITS 5
+#define PNG_QUANTIZE_GREEN_BITS 5
+#define PNG_QUANTIZE_RED_BITS 5
+#define PNG_TEXT_Z_DEFAULT_COMPRESSION (-1)
+#define PNG_TEXT_Z_DEFAULT_STRATEGY 0
+#define PNG_USER_CHUNK_CACHE_MAX 1000
+#define PNG_USER_CHUNK_MALLOC_MAX 8000000
+#define PNG_USER_HEIGHT_MAX 1000000
+#define PNG_USER_WIDTH_MAX 1000000
+#define PNG_ZBUF_SIZE 8192
+#define PNG_ZLIB_VERNUM 0 /* unknown */
+#define PNG_Z_DEFAULT_COMPRESSION (-1)
+#define PNG_Z_DEFAULT_NOFILTER_STRATEGY 0
+#define PNG_Z_DEFAULT_STRATEGY 1
+#define PNG_sCAL_PRECISION 5
+#define PNG_sRGB_PROFILE_CHECKS 2
+/* end of settings */
+#endif /* PNGLCONF_H */
diff --git a/extern/libpng/scripts/pnglibconf.mak b/extern/libpng/scripts/pnglibconf.mak
new file mode 100755
index 0000000000..c125ca2c97
--- /dev/null
+++ b/extern/libpng/scripts/pnglibconf.mak
@@ -0,0 +1,55 @@
+#!/usr/bin/make -f
+# pnglibconf.mak - standard make lines for pnglibconf.h
+#
+# These lines are copied from Makefile.am, they illustrate
+# how to automate the build of pnglibconf.h from scripts/pnglibconf.dfa
+# given just 'awk', a C preprocessor and standard command line utilities
+
+# Override as appropriate, these definitions can be overridden on
+# the make command line (AWK='nawk' for example).
+AWK = gawk
+AWK = mawk
+AWK = nawk
+AWK = one-true-awk
+AWK = awk  # Crashes on SunOS 5.10 - use 'nawk'
+CPP = $(CC) -E # On SUN OS 5.10 if this causes problems use /lib/cpp
+
+MOVE = mv
+DELETE = rm -f
+ECHO = echo
+DFA_XTRA = # Put your configuration file here, see scripts/pnglibconf.dfa.  Eg:
+# DFA_XTRA = pngusr.dfa
+
+# CPPFLAGS should contain the options to control the result,
+# but DEFS and CFLAGS are also supported here, override
+# as appropriate
+DFNFLAGS = $(DEFS) $(CPPFLAGS) $(CFLAGS)
+
+# srcdir is a defacto standard for the location of the source
+srcdir = .
+
+# The standard pnglibconf.h exists as scripts/pnglibconf.h.prebuilt,
+# copy this if the following doesn't work.
+pnglibconf.h: pnglibconf.dfn
+	$(DELETE) $@ pnglibconf.c pnglibconf.out pnglibconf.tmp
+	$(ECHO) '#include "pnglibconf.dfn"' >pnglibconf.c
+	$(ECHO) "If '$(CC) -E' crashes try /lib/cpp (e.g. CPP='/lib/cpp')" >&2
+	$(CPP) $(DFNFLAGS) pnglibconf.c >pnglibconf.out
+	$(AWK) -f "$(srcdir)/scripts/dfn.awk" out="pnglibconf.tmp" pnglibconf.out 1>&2
+	$(MOVE) pnglibconf.tmp $@
+
+pnglibconf.dfn: $(srcdir)/scripts/pnglibconf.dfa $(srcdir)/scripts/options.awk $(srcdir)/pngconf.h $(srcdir)/pngusr.dfa $(DFA_XTRA)
+	$(DELETE) $@ pnglibconf.pre pnglibconf.tmp
+	$(ECHO) "Calling $(AWK) from scripts/pnglibconf.mak" >&2
+	$(ECHO) "If 'awk' crashes try a better awk (e.g. AWK='nawk')" >&2
+	$(AWK) -f $(srcdir)/scripts/options.awk out="pnglibconf.pre"\
+	    version=search $(srcdir)/pngconf.h $(srcdir)/scripts/pnglibconf.dfa\
+	    $(srcdir)/pngusr.dfa $(DFA_XTRA) 1>&2
+	$(AWK) -f $(srcdir)/scripts/options.awk out="pnglibconf.tmp" pnglibconf.pre 1>&2
+	$(MOVE) pnglibconf.tmp $@
+
+clean-pnglibconf:
+	$(DELETE) pnglibconf.h pnglibconf.c pnglibconf.out pnglibconf.pre \
+	pnglibconf.dfn
+
+clean: clean-pnglibconf
diff --git a/extern/libpng/scripts/pngwin.rc b/extern/libpng/scripts/pngwin.rc
new file mode 100644
index 0000000000..9335cbbe03
--- /dev/null
+++ b/extern/libpng/scripts/pngwin.rc
@@ -0,0 +1,112 @@
+#define PNG_VERSION_INFO_ONLY
+
+#include <windows.h>
+#include "../png.h"
+
+#define _QUOTE(x) # x
+#define QUOTE(x) _QUOTE(x)
+
+#define PNG_LIBPNG_DLLFNAME "LIBPNG"
+
+/* Support deprecated PRIVATEBUILD macro */
+#if defined(PRIVATEBUILD) && !defined(PNG_USER_PRIVATEBUILD)
+#  define PNG_USER_PRIVATEBUILD PRIVATEBUILD
+#endif
+
+#if defined(PNG_USER_DLLFNAME_POSTFIX) && !defined(PNG_USER_PRIVATEBUILD)
+#  error "PNG_USER_PRIVATEBUILD must be defined as a string describing the\
+ custom changes made to the library."
+#endif
+
+/* Prioritize PNG_USER_x over PNG_LIBPNG_x */
+#ifdef PNG_USER_DLLFNAME_POSTFIX
+#  undef PNG_LIBPNG_DLLFNAME_POSTFIX
+#  define PNG_LIBPNG_DLLFNAME_POSTFIX PNG_USER_DLLFNAME_POSTFIX
+#endif
+
+#ifdef PNG_USER_VERSIONINFO_COMMENTS
+#  undef PNG_LIBPNG_VERSIONINFO_COMMENTS
+#  define PNG_LIBPNG_VERSIONINFO_COMMENTS PNG_USER_VERSIONINFO_COMMENTS
+#endif
+
+#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
+#  define VS_DEBUG VS_FF_DEBUG
+#  ifndef PNG_LIBPNG_DLLFNAME_POSTFIX
+#    define PNG_LIBPNG_DLLFNAME_POSTFIX "D"
+#  endif /* PNG_LIBPNG_DLLFNAME_POSTFIX */
+#  ifndef PNG_LIBPNG_VERSIONINFO_COMMENTS
+#    define PNG_LIBPNG_VERSIONINFO_COMMENTS "PNG_DEBUG=" QUOTE(PNG_DEBUG)
+#  endif /* PNG_LIBPNG_VERSIONINFO_COMMENTS */
+#else
+#  define VS_DEBUG 0
+#  ifndef PNG_LIBPNG_DLLFNAME_POSTFIX
+#     define PNG_LIBPNG_DLLFNAME_POSTFIX
+#  endif /* PNG_LIBPNG_DLLFNAME_POSTFIX */
+#endif /* defined(DEBUG)... */
+
+#ifdef PNG_USER_PRIVATEBUILD
+#  define VS_PRIVATEBUILD VS_FF_PRIVATEBUILD
+#else
+#  define VS_PRIVATEBUILD 0
+#endif /* PNG_USER_PRIVATEBUILD */
+
+#ifdef PNG_LIBPNG_SPECIALBUILD
+#  define VS_SPECIALBUILD VS_FF_SPECIALBUILD
+#else
+#  define VS_SPECIALBUILD 0
+#endif /* PNG_LIBPNG_BUILD_SPECIAL */
+
+#if ((PNG_LIBPNG_BUILD_BASE_TYPE & PNG_LIBPNG_RELEASE_STATUS_MASK) !=\
+      PNG_LIBPNG_BUILD_STABLE)
+#  define VS_PRERELEASE VS_FF_PRERELEASE
+#  define VS_PATCHED 0
+#else
+#  define VS_PRERELEASE 0
+#  if (PNG_LIBPNG_BUILD_BASE_TYPE & PNG_LIBPNG_BUILD_PATCHED)
+#    define VS_PATCHED VS_FF_PATCHED
+#  else
+#    define VS_PATCHED 0
+#  endif
+#endif
+
+VS_VERSION_INFO VERSIONINFO
+FILEVERSION PNG_LIBPNG_VER_MAJOR, PNG_LIBPNG_VER_MINOR, PNG_LIBPNG_VER_RELEASE, PNG_LIBPNG_VER_BUILD
+PRODUCTVERSION PNG_LIBPNG_VER_MAJOR, PNG_LIBPNG_VER_MINOR, PNG_LIBPNG_VER_RELEASE, PNG_LIBPNG_VER_BUILD
+FILEFLAGSMASK VS_FFI_FILEFLAGSMASK
+FILEFLAGS VS_DEBUG | VS_PRIVATEBUILD | VS_SPECIALBUILD | VS_PRERELEASE | VS_PATCHED
+FILEOS VOS__WINDOWS32
+FILETYPE VFT_DLL
+FILESUBTYPE VFT2_UNKNOWN
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN BLOCK "040904E4" /* Language type = U.S English(0x0409) and Character Set = Windows, Multilingual(0x04E4) */
+    BEGIN
+#ifdef PNG_LIBPNG_VERSIONINFO_COMMENTS
+      VALUE "Comments", PNG_LIBPNG_VERSIONINFO_COMMENTS "\000"
+#endif /* PNG_LIBPNG_VERSIONINFO_COMMENTS */
+#ifdef PNG_USER_VERSIONINFO_COMPANYNAME
+      VALUE "CompanyName", PNG_USER_VERSIONINFO_COMPANYNAME "\000"
+#endif /* PNG_USER_VERSIONINFO_COMPANYNAME */
+      VALUE "FileDescription", "PNG image compression library\000"
+      VALUE "FileVersion", PNG_LIBPNG_VER_STRING "\000"
+      VALUE "InternalName", PNG_LIBPNG_DLLFNAME QUOTE(PNG_LIBPNG_VER_DLLNUM) PNG_LIBPNG_DLLFNAME_POSTFIX " (Windows 32 bit)\000"
+      VALUE "LegalCopyright", "\251 1998-2009 Glenn Randers-Pehrson et al.\000"
+#ifdef PNG_USER_VERSIONINFO_LEGALTRADEMARKS
+      VALUE "LegalTrademarks", PNG_USER_VERSIONINFO_LEGALTRADEMARKS "\000"
+#endif /* PNG_USER_VERSIONINFO_LEGALTRADEMARKS */
+      VALUE "OriginalFilename", PNG_LIBPNG_DLLFNAME QUOTE(PNG_LIBPNG_VER_DLLNUM) PNG_LIBPNG_DLLFNAME_POSTFIX ".DLL\000"
+#ifdef PNG_USER_PRIVATEBUILD
+      VALUE "PrivateBuild", PNG_USER_PRIVATEBUILD "\000"
+#endif /* PNG_USER_PRIVATEBUILD */
+      VALUE "ProductName", "LibPNG\000"
+      VALUE "ProductVersion", "1\000"
+#ifdef PNG_LIBPNG_SPECIALBUILD
+      VALUE "SpecialBuild", PNG_LIBPNG_SPECIALBUILD "\000"
+#endif /* PNG_LIBPNG_SPECIALBUILD */
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x0409, 0x04E4
+  END
+END
diff --git a/extern/libpng/scripts/prefix.c b/extern/libpng/scripts/prefix.c
new file mode 100644
index 0000000000..8b604a0919
--- /dev/null
+++ b/extern/libpng/scripts/prefix.c
@@ -0,0 +1,24 @@
+
+/* prefix.c - generate an unprefixed symbol list
+ *
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2013-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+        PNG_DFN "@" name "@"
+
+/* The configuration information *before* the additional of symbol renames,
+ * the list is the C name list; no symbol prefix.
+ */
+#include "pnglibconf.out"
+
+PNG_DFN_START_SORT 1
+
+#include "../png.h"
+
+PNG_DFN_END_SORT
diff --git a/extern/libpng/scripts/smakefile.ppc b/extern/libpng/scripts/smakefile.ppc
new file mode 100644
index 0000000000..2e7380b1f9
--- /dev/null
+++ b/extern/libpng/scripts/smakefile.ppc
@@ -0,0 +1,34 @@
+# Amiga powerUP (TM) Makefile
+# makefile for libpng and SAS C V6.58/7.00 PPC compiler
+# Copyright (C) 1998 by Andreas R. Kleinert
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+CC       = scppc
+CFLAGS   = NOSTKCHK NOSINT OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL IDIR /zlib \
+           OPTLOOP OPTRDEP=8 OPTDEP=8 OPTCOMP=8
+LIBNAME  = libpng.a
+AR       = ppc-amigaos-ar
+AR_FLAGS = cr
+RANLIB   = ppc-amigaos-ranlib
+LDFLAGS  = -r -o
+LDLIBS   =  ../zlib/libzip.a LIB:scppc.a
+LN       = ppc-amigaos-ld
+RM       = delete quiet
+MKDIR    = makedir
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o pngread.o \
+       pngerror.o pngpread.o pngwrite.o pngrtran.o pngwtran.o pngrio.o \
+       pngwio.o pngmem.o
+
+all: $(LIBNAME) pngtest
+
+$(LIBNAME): $(OBJS)
+            $(AR) $(AR_FLAGS) $@ $(OBJS)
+            $(RANLIB) $@
+
+pngtest: pngtest.o $(LIBNAME)
+        $(LN) $(LDFLAGS) pngtest LIB:c_ppc.o pngtest.o $(LIBNAME) $(LDLIBS) \
+LIB:end.o
diff --git a/extern/libpng/scripts/sym.c b/extern/libpng/scripts/sym.c
new file mode 100644
index 0000000000..ea9e4c5070
--- /dev/null
+++ b/extern/libpng/scripts/sym.c
@@ -0,0 +1,15 @@
+
+/* sym.c - define format of libpng.sym
+ *
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2011-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+        PNG_DFN "@" SYMBOL_PREFIX "@@" name "@"
+
+#include "../png.h"
diff --git a/extern/libpng/scripts/symbols.c b/extern/libpng/scripts/symbols.c
new file mode 100644
index 0000000000..28b841d8b6
--- /dev/null
+++ b/extern/libpng/scripts/symbols.c
@@ -0,0 +1,58 @@
+
+/* symbols.c - find all exported symbols
+ *
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2011-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* NOTE: making 'symbols.chk' checks both that the exported
+ * symbols in the library don't change and (implicitly) that
+ * scripts/pnglibconf.h.prebuilt is as expected.
+ * If scripts/pnglibconf.h.prebuilt is remade using
+ * scripts/pnglibconf.dfa then this checks the .dfa file too.
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+        PNG_DFN "@" name "@ @@" ordinal "@"
+#define PNG_REMOVED(ordinal, type, name, args, attributes)\
+        PNG_DFN "; @" name "@ @@" ordinal "@"
+#define PNG_EXPORT_LAST_ORDINAL(ordinal)\
+        PNG_DFN "; @@" ordinal "@"
+
+/* Read the defaults, but use scripts/pnglibconf.h.prebuilt; the 'standard'
+ * header file.
+ */
+#include "pnglibconf.h.prebuilt"
+#include "../png.h"
+
+/* Some things are turned off by default.  Turn these things
+ * on here (by hand) to get the APIs they expose and validate
+ * that no harm is done.  This list is the set of options
+ * defaulted to 'off' in scripts/pnglibconf.dfa
+ *
+ * Maintenance: if scripts/pnglibconf.dfa options are changed
+ * from, or to, 'disabled' this needs updating!
+ */
+#define PNG_BENIGN_ERRORS_SUPPORTED
+#define PNG_ERROR_NUMBERS_SUPPORTED
+#define PNG_READ_BIG_ENDIAN_SUPPORTED  /* should do nothing! */
+#define PNG_INCH_CONVERSIONS_SUPPORTED
+#define PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+#define PNG_SET_OPTION_SUPPORTED
+
+#undef PNG_H
+#include "../png.h"
+
+/* Finally there are a couple of places where option support
+ * actually changes the APIs revealed using a #if/#else/#endif
+ * test in png.h, test these here.
+ */
+#undef  PNG_FLOATING_POINT_SUPPORTED /* Exposes 'fixed' APIs */
+#undef  PNG_ERROR_TEXT_SUPPORTED     /* Exposes unsupported APIs */
+
+#undef PNG_H
+#include "../png.h"
diff --git a/extern/libpng/scripts/symbols.def b/extern/libpng/scripts/symbols.def
new file mode 100644
index 0000000000..82494bbf94
--- /dev/null
+++ b/extern/libpng/scripts/symbols.def
@@ -0,0 +1,255 @@
+;--------------------------------------------------------------
+; LIBPNG symbol list as a Win32 DEF file
+; Contains all the symbols that can be exported from libpng
+;--------------------------------------------------------------
+LIBRARY
+
+EXPORTS
+ png_access_version_number @1
+ png_set_sig_bytes @2
+ png_sig_cmp @3
+ png_create_read_struct @4
+ png_create_write_struct @5
+ png_get_compression_buffer_size @6
+ png_set_compression_buffer_size @7
+ png_set_longjmp_fn @8
+ png_longjmp @9
+ png_reset_zstream @10
+ png_create_read_struct_2 @11
+ png_create_write_struct_2 @12
+ png_write_sig @13
+ png_write_chunk @14
+ png_write_chunk_start @15
+ png_write_chunk_data @16
+ png_write_chunk_end @17
+ png_create_info_struct @18
+ png_info_init_3 @19
+ png_write_info_before_PLTE @20
+ png_write_info @21
+ png_read_info @22
+ png_convert_to_rfc1123 @23
+ png_convert_from_struct_tm @24
+ png_convert_from_time_t @25
+ png_set_expand @26
+ png_set_expand_gray_1_2_4_to_8 @27
+ png_set_palette_to_rgb @28
+ png_set_tRNS_to_alpha @29
+ png_set_bgr @30
+ png_set_gray_to_rgb @31
+ png_set_rgb_to_gray @32
+ png_set_rgb_to_gray_fixed @33
+ png_get_rgb_to_gray_status @34
+ png_build_grayscale_palette @35
+ png_set_strip_alpha @36
+ png_set_swap_alpha @37
+ png_set_invert_alpha @38
+ png_set_filler @39
+ png_set_add_alpha @40
+ png_set_swap @41
+ png_set_packing @42
+ png_set_packswap @43
+ png_set_shift @44
+ png_set_interlace_handling @45
+ png_set_invert_mono @46
+ png_set_background @47
+ png_set_strip_16 @48
+ png_set_quantize @49
+ png_set_gamma @50
+ png_set_flush @51
+ png_write_flush @52
+ png_start_read_image @53
+ png_read_update_info @54
+ png_read_rows @55
+ png_read_row @56
+ png_read_image @57
+ png_write_row @58
+ png_write_rows @59
+ png_write_image @60
+ png_write_end @61
+ png_read_end @62
+ png_destroy_info_struct @63
+ png_destroy_read_struct @64
+ png_destroy_write_struct @65
+ png_set_crc_action @66
+ png_set_filter @67
+ png_set_filter_heuristics @68
+ png_set_compression_level @69
+ png_set_compression_mem_level @70
+ png_set_compression_strategy @71
+ png_set_compression_window_bits @72
+ png_set_compression_method @73
+ png_init_io @74
+ png_set_error_fn @75
+ png_get_error_ptr @76
+ png_set_write_fn @77
+ png_set_read_fn @78
+ png_get_io_ptr @79
+ png_set_read_status_fn @80
+ png_set_write_status_fn @81
+ png_set_mem_fn @82
+ png_get_mem_ptr @83
+ png_set_read_user_transform_fn @84
+ png_set_write_user_transform_fn @85
+ png_set_user_transform_info @86
+ png_get_user_transform_ptr @87
+ png_set_read_user_chunk_fn @88
+ png_get_user_chunk_ptr @89
+ png_set_progressive_read_fn @90
+ png_get_progressive_ptr @91
+ png_process_data @92
+ png_progressive_combine_row @93
+ png_malloc @94
+ png_calloc @95
+ png_malloc_warn @96
+ png_free @97
+ png_free_data @98
+ png_data_freer @99
+ png_malloc_default @100
+ png_free_default @101
+ png_error @102
+ png_chunk_error @103
+ png_err @104
+ png_warning @105
+ png_chunk_warning @106
+ png_benign_error @107
+ png_chunk_benign_error @108
+ png_set_benign_errors @109
+ png_get_valid @110
+ png_get_rowbytes @111
+ png_get_rows @112
+ png_set_rows @113
+ png_get_channels @114
+ png_get_image_width @115
+ png_get_image_height @116
+ png_get_bit_depth @117
+ png_get_color_type @118
+ png_get_filter_type @119
+ png_get_interlace_type @120
+ png_get_compression_type @121
+ png_get_pixels_per_meter @122
+ png_get_x_pixels_per_meter @123
+ png_get_y_pixels_per_meter @124
+ png_get_pixel_aspect_ratio @125
+ png_get_x_offset_pixels @126
+ png_get_y_offset_pixels @127
+ png_get_x_offset_microns @128
+ png_get_y_offset_microns @129
+ png_get_signature @130
+ png_get_bKGD @131
+ png_set_bKGD @132
+ png_get_cHRM @133
+ png_get_cHRM_fixed @134
+ png_set_cHRM @135
+ png_set_cHRM_fixed @136
+ png_get_gAMA @137
+ png_get_gAMA_fixed @138
+ png_set_gAMA @139
+ png_set_gAMA_fixed @140
+ png_get_hIST @141
+ png_set_hIST @142
+ png_get_IHDR @143
+ png_set_IHDR @144
+ png_get_oFFs @145
+ png_set_oFFs @146
+ png_get_pCAL @147
+ png_set_pCAL @148
+ png_get_pHYs @149
+ png_set_pHYs @150
+ png_get_PLTE @151
+ png_set_PLTE @152
+ png_get_sBIT @153
+ png_set_sBIT @154
+ png_get_sRGB @155
+ png_set_sRGB @156
+ png_set_sRGB_gAMA_and_cHRM @157
+ png_get_iCCP @158
+ png_set_iCCP @159
+ png_get_sPLT @160
+ png_set_sPLT @161
+ png_get_text @162
+ png_set_text @163
+ png_get_tIME @164
+ png_set_tIME @165
+ png_get_tRNS @166
+ png_set_tRNS @167
+ png_get_sCAL @168
+ png_get_sCAL_s @169
+ png_set_sCAL @170
+ png_set_sCAL_s @171
+ png_set_keep_unknown_chunks @172
+ png_handle_as_unknown @173
+ png_set_unknown_chunks @174
+ png_set_unknown_chunk_location @175
+ png_get_unknown_chunks @176
+ png_set_invalid @177
+ png_read_png @178
+ png_write_png @179
+ png_get_copyright @180
+ png_get_header_ver @181
+ png_get_header_version @182
+ png_get_libpng_ver @183
+ png_permit_mng_features @184
+ png_set_strip_error_numbers @185
+ png_set_user_limits @186
+ png_get_user_width_max @187
+ png_get_user_height_max @188
+ png_set_chunk_cache_max @189
+ png_get_chunk_cache_max @190
+ png_set_chunk_malloc_max @191
+ png_get_chunk_malloc_max @192
+ png_get_pixels_per_inch @193
+ png_get_x_pixels_per_inch @194
+ png_get_y_pixels_per_inch @195
+ png_get_x_offset_inches @196
+ png_get_y_offset_inches @197
+ png_get_pHYs_dpi @198
+ png_get_io_state @199
+ png_get_uint_32 @201
+ png_get_uint_16 @202
+ png_get_int_32 @203
+ png_get_uint_31 @204
+ png_save_uint_32 @205
+ png_save_int_32 @206
+ png_save_uint_16 @207
+ png_set_gamma_fixed @208
+ png_set_filter_heuristics_fixed @209
+ png_get_pixel_aspect_ratio_fixed @210
+ png_get_x_offset_inches_fixed @211
+ png_get_y_offset_inches_fixed @212
+ png_set_sCAL_fixed @213
+ png_get_sCAL_fixed @214
+ png_set_background_fixed @215
+ png_get_io_chunk_type @216
+ png_get_current_row_number @217
+ png_get_current_pass_number @218
+ png_process_data_pause @219
+ png_process_data_skip @220
+ png_set_expand_16 @221
+ png_set_text_compression_level @222
+ png_set_text_compression_mem_level @223
+ png_set_text_compression_strategy @224
+ png_set_text_compression_window_bits @225
+ png_set_text_compression_method @226
+ png_set_alpha_mode @227
+ png_set_alpha_mode_fixed @228
+ png_set_scale_16 @229
+ png_get_cHRM_XYZ @230
+ png_get_cHRM_XYZ_fixed @231
+ png_set_cHRM_XYZ @232
+ png_set_cHRM_XYZ_fixed @233
+ png_image_begin_read_from_file @234
+ png_image_begin_read_from_stdio @235
+ png_image_begin_read_from_memory @236
+ png_image_finish_read @237
+ png_image_free @238
+ png_image_write_to_file @239
+ png_image_write_to_stdio @240
+ png_convert_to_rfc1123_buffer @241
+ png_set_check_for_invalid_index @242
+ png_get_palette_max @243
+ png_set_option @244
+ png_image_write_to_memory @245
+ png_get_eXIf @246
+ png_set_eXIf @247
+ png_get_eXIf_1 @248
+ png_set_eXIf_1 @249
diff --git a/extern/libpng/scripts/test.cmake.in b/extern/libpng/scripts/test.cmake.in
new file mode 100644
index 0000000000..fa6a889bba
--- /dev/null
+++ b/extern/libpng/scripts/test.cmake.in
@@ -0,0 +1,31 @@
+# test.cmake.in
+
+# Copyright (C) 2016 Glenn Randers-Pehrson
+# Written by Roger Leigh, 2016
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+set(TEST_OPTIONS "@TEST_OPTIONS@")
+set(TEST_FILES "@TEST_FILES@")
+
+foreach(file ${TEST_FILES})
+  file(TO_NATIVE_PATH "${file}" native_file)
+  list(APPEND NATIVE_TEST_FILES "${native_file}")
+endforeach()
+
+# Add the directory containing libpng to the PATH (Windows only)
+if(WIN32)
+  get_filename_component(LIBPNG_DIR "${LIBPNG}" PATH)
+  file(TO_NATIVE_PATH "${LIBPNG_DIR}" LIBPNG_DIR)
+  set(ENV{PATH} "${LIBPNG_DIR};$ENV{PATH}")
+endif()
+
+execute_process(COMMAND "${CMAKE_COMMAND}" -E echo "Running ${TEST_COMMAND}" ${TEST_OPTIONS} ${NATIVE_TEST_FILES})
+
+execute_process(COMMAND "${TEST_COMMAND}" ${TEST_OPTIONS} ${NATIVE_TEST_FILES}
+                RESULT_VARIABLE TEST_STATUS)
+if(TEST_STATUS)
+  message(FATAL_ERROR "Returned failed status ${TEST_STATUS}!")
+endif()
diff --git a/extern/libpng/scripts/vers.c b/extern/libpng/scripts/vers.c
new file mode 100644
index 0000000000..de7319716f
--- /dev/null
+++ b/extern/libpng/scripts/vers.c
@@ -0,0 +1,19 @@
+
+/* vers.c - define format of libpng.vers
+ *
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2011-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+        PNG_DFN " @" SYMBOL_PREFIX "@@" name "@;"
+
+PNG_DFN "@" PNGLIB_LIBNAME "@ {global:"
+
+#include "../png.h"
+
+PNG_DFN "local: *; };"
diff --git a/extern/libpng/test-driver b/extern/libpng/test-driver
new file mode 100755
index 0000000000..b8521a482e
--- /dev/null
+++ b/extern/libpng/test-driver
@@ -0,0 +1,148 @@
+#! /bin/sh
+# test-driver - basic testsuite driver script.
+
+scriptversion=2018-03-07.03; # UTC
+
+# Copyright (C) 2011-2018 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# This file is maintained in Automake, please report
+# bugs to <bug-automake@gnu.org> or send patches to
+# <automake-patches@gnu.org>.
+
+# Make unconditional expansion of undefined variables an error.  This
+# helps a lot in preventing typo-related bugs.
+set -u
+
+usage_error ()
+{
+  echo "$0: $*" >&2
+  print_usage >&2
+  exit 2
+}
+
+print_usage ()
+{
+  cat <<END
+Usage:
+  test-driver --test-name=NAME --log-file=PATH --trs-file=PATH
+              [--expect-failure={yes|no}] [--color-tests={yes|no}]
+              [--enable-hard-errors={yes|no}] [--]
+              TEST-SCRIPT [TEST-SCRIPT-ARGUMENTS]
+The '--test-name', '--log-file' and '--trs-file' options are mandatory.
+END
+}
+
+test_name= # Used for reporting.
+log_file=  # Where to save the output of the test script.
+trs_file=  # Where to save the metadata of the test run.
+expect_failure=no
+color_tests=no
+enable_hard_errors=yes
+while test $# -gt 0; do
+  case $1 in
+  --help) print_usage; exit $?;;
+  --version) echo "test-driver $scriptversion"; exit $?;;
+  --test-name) test_name=$2; shift;;
+  --log-file) log_file=$2; shift;;
+  --trs-file) trs_file=$2; shift;;
+  --color-tests) color_tests=$2; shift;;
+  --expect-failure) expect_failure=$2; shift;;
+  --enable-hard-errors) enable_hard_errors=$2; shift;;
+  --) shift; break;;
+  -*) usage_error "invalid option: '$1'";;
+   *) break;;
+  esac
+  shift
+done
+
+missing_opts=
+test x"$test_name" = x && missing_opts="$missing_opts --test-name"
+test x"$log_file"  = x && missing_opts="$missing_opts --log-file"
+test x"$trs_file"  = x && missing_opts="$missing_opts --trs-file"
+if test x"$missing_opts" != x; then
+  usage_error "the following mandatory options are missing:$missing_opts"
+fi
+
+if test $# -eq 0; then
+  usage_error "missing argument"
+fi
+
+if test $color_tests = yes; then
+  # Keep this in sync with 'lib/am/check.am:$(am__tty_colors)'.
+  red='' # Red.
+  grn='' # Green.
+  lgn='' # Light green.
+  blu='' # Blue.
+  mgn='' # Magenta.
+  std=''     # No color.
+else
+  red= grn= lgn= blu= mgn= std=
+fi
+
+do_exit='rm -f $log_file $trs_file; (exit $st); exit $st'
+trap "st=129; $do_exit" 1
+trap "st=130; $do_exit" 2
+trap "st=141; $do_exit" 13
+trap "st=143; $do_exit" 15
+
+# Test script is run here.
+"$@" >$log_file 2>&1
+estatus=$?
+
+if test $enable_hard_errors = no && test $estatus -eq 99; then
+  tweaked_estatus=1
+else
+  tweaked_estatus=$estatus
+fi
+
+case $tweaked_estatus:$expect_failure in
+  0:yes) col=$red res=XPASS recheck=yes gcopy=yes;;
+  0:*)   col=$grn res=PASS  recheck=no  gcopy=no;;
+  77:*)  col=$blu res=SKIP  recheck=no  gcopy=yes;;
+  99:*)  col=$mgn res=ERROR recheck=yes gcopy=yes;;
+  *:yes) col=$lgn res=XFAIL recheck=no  gcopy=yes;;
+  *:*)   col=$red res=FAIL  recheck=yes gcopy=yes;;
+esac
+
+# Report the test outcome and exit status in the logs, so that one can
+# know whether the test passed or failed simply by looking at the '.log'
+# file, without the need of also peaking into the corresponding '.trs'
+# file (automake bug#11814).
+echo "$res $test_name (exit status: $estatus)" >>$log_file
+
+# Report outcome to console.
+echo "${col}${res}${std}: $test_name"
+
+# Register the test result, and other relevant metadata.
+echo ":test-result: $res" > $trs_file
+echo ":global-test-result: $res" >> $trs_file
+echo ":recheck: $recheck" >> $trs_file
+echo ":copy-in-global-log: $gcopy" >> $trs_file
+
+# Local Variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
diff --git a/extern/libpng/tests/pngimage-full b/extern/libpng/tests/pngimage-full
new file mode 100755
index 0000000000..1198ed05c0
--- /dev/null
+++ b/extern/libpng/tests/pngimage-full
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngimage --exhaustive --list-combos --log "${srcdir}/contrib/pngsuite/"*.png
diff --git a/extern/libpng/tests/pngimage-quick b/extern/libpng/tests/pngimage-quick
new file mode 100755
index 0000000000..328dc27b5d
--- /dev/null
+++ b/extern/libpng/tests/pngimage-quick
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngimage --list-combos --log "${srcdir}/contrib/pngsuite/"*.png
diff --git a/extern/libpng/tests/pngstest b/extern/libpng/tests/pngstest
new file mode 100755
index 0000000000..9d1b7764e5
--- /dev/null
+++ b/extern/libpng/tests/pngstest
@@ -0,0 +1,54 @@
+#!/bin/sh
+#
+# Usage:
+#
+#  tests/pngstest gamma alpha
+#
+# Run ./pngstest on the PNG files in $srcdir/contrib/testpngs which have the
+# given gamma and opacity:
+#
+#  gamma: one of; linear, 1.8, sRGB, none.
+#  alpha: one of; opaque, tRNS, alpha, none.  'none' is equivalent to !alpha
+#
+# NOTE: the temporary files pngstest generates have the base name gamma-alpha to
+# avoid issues with make -j
+#
+gamma="$1"
+shift
+alpha="$1"
+shift
+args=
+LC_ALL="C" # fix glob sort order to ASCII:
+for f in "${srcdir}/contrib/testpngs/"*.png
+do
+   g=
+   case "$f" in
+      *-linear[.-]*)
+         test "$gamma" = "linear" && g="$f";;
+
+      *-sRGB[.-]*)
+         test "$gamma" = "sRGB" && g="$f";;
+
+      *-1.8[.-]*)
+         test "$gamma" = "1.8" && g="$f";;
+
+      *)
+         test "$gamma" = "none" && g="$f";;
+   esac
+
+   case "$g" in
+      "")
+         :;;
+
+      *-alpha[-.]*)
+         test "$alpha" = "alpha" && args="$args $g";;
+
+      *-tRNS[-.]*)
+         test "$alpha" = "tRNS" -o "$alpha" = "none" && args="$args $g";;
+
+      *)
+         test "$alpha" = "opaque" -o "$alpha" = "none" && args="$args $g";;
+   esac
+done
+# This only works if the arguments don't contain spaces; they don't.
+exec ./pngstest --tmpfile "${gamma}-${alpha}-" --log ${1+"$@"} $args
diff --git a/extern/libpng/tests/pngstest-1.8 b/extern/libpng/tests/pngstest-1.8
new file mode 100755
index 0000000000..b2ec21bf64
--- /dev/null
+++ b/extern/libpng/tests/pngstest-1.8
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" 1.8 none
diff --git a/extern/libpng/tests/pngstest-1.8-alpha b/extern/libpng/tests/pngstest-1.8-alpha
new file mode 100755
index 0000000000..d00596d558
--- /dev/null
+++ b/extern/libpng/tests/pngstest-1.8-alpha
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" 1.8 alpha
diff --git a/extern/libpng/tests/pngstest-linear b/extern/libpng/tests/pngstest-linear
new file mode 100755
index 0000000000..4a5b3fe8c3
--- /dev/null
+++ b/extern/libpng/tests/pngstest-linear
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" linear none
diff --git a/extern/libpng/tests/pngstest-linear-alpha b/extern/libpng/tests/pngstest-linear-alpha
new file mode 100755
index 0000000000..4114210363
--- /dev/null
+++ b/extern/libpng/tests/pngstest-linear-alpha
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" linear alpha
diff --git a/extern/libpng/tests/pngstest-none b/extern/libpng/tests/pngstest-none
new file mode 100755
index 0000000000..09ad740b58
--- /dev/null
+++ b/extern/libpng/tests/pngstest-none
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" none none
diff --git a/extern/libpng/tests/pngstest-none-alpha b/extern/libpng/tests/pngstest-none-alpha
new file mode 100755
index 0000000000..af6083ff83
--- /dev/null
+++ b/extern/libpng/tests/pngstest-none-alpha
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" none alpha
diff --git a/extern/libpng/tests/pngstest-sRGB b/extern/libpng/tests/pngstest-sRGB
new file mode 100755
index 0000000000..d8460812c2
--- /dev/null
+++ b/extern/libpng/tests/pngstest-sRGB
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" sRGB none
diff --git a/extern/libpng/tests/pngstest-sRGB-alpha b/extern/libpng/tests/pngstest-sRGB-alpha
new file mode 100755
index 0000000000..f1e57d339c
--- /dev/null
+++ b/extern/libpng/tests/pngstest-sRGB-alpha
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" sRGB alpha
diff --git a/extern/libpng/tests/pngtest b/extern/libpng/tests/pngtest
new file mode 100755
index 0000000000..813973b23e
--- /dev/null
+++ b/extern/libpng/tests/pngtest
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngtest --strict ${srcdir}/pngtest.png
diff --git a/extern/libpng/tests/pngtest-badpngs b/extern/libpng/tests/pngtest-badpngs
new file mode 100755
index 0000000000..77775232b2
--- /dev/null
+++ b/extern/libpng/tests/pngtest-badpngs
@@ -0,0 +1,13 @@
+#!/bin/sh
+
+# various crashers
+# using --relaxed because some come from fuzzers that don't maintain CRC's
+
+./pngtest --relaxed ${srcdir}/contrib/testpngs/crashers/badcrc.png
+./pngtest --relaxed ${srcdir}/contrib/testpngs/crashers/badadler.png
+./pngtest --xfail ${srcdir}/contrib/testpngs/crashers/bad_iCCP.png
+./pngtest --xfail ${srcdir}/contrib/testpngs/crashers/empty_ancillary_chunks.png
+./pngtest --xfail ${srcdir}/contrib/testpngs/crashers/huge_*_chunk.png \
+    ${srcdir}/contrib/testpngs/crashers/huge_*safe_to_copy.png
+
+exec ./pngtest --xfail ${srcdir}/contrib/testpngs/crashers/huge_IDAT.png
diff --git a/extern/libpng/tests/pngunknown-IDAT b/extern/libpng/tests/pngunknown-IDAT
new file mode 100755
index 0000000000..8e7281aa84
--- /dev/null
+++ b/extern/libpng/tests/pngunknown-IDAT
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict default=discard IDAT=save "${srcdir}/pngtest.png"
diff --git a/extern/libpng/tests/pngunknown-discard b/extern/libpng/tests/pngunknown-discard
new file mode 100755
index 0000000000..c96dab370c
--- /dev/null
+++ b/extern/libpng/tests/pngunknown-discard
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict default=discard "${srcdir}/pngtest.png"
diff --git a/extern/libpng/tests/pngunknown-if-safe b/extern/libpng/tests/pngunknown-if-safe
new file mode 100755
index 0000000000..31a4954fbb
--- /dev/null
+++ b/extern/libpng/tests/pngunknown-if-safe
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict default=if-safe "${srcdir}/pngtest.png"
diff --git a/extern/libpng/tests/pngunknown-sAPI b/extern/libpng/tests/pngunknown-sAPI
new file mode 100755
index 0000000000..88a1f6be2d
--- /dev/null
+++ b/extern/libpng/tests/pngunknown-sAPI
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict bKGD=save cHRM=save gAMA=save all=discard iCCP=save sBIT=save sRGB=save eXIf=save "${srcdir}/pngtest.png"
diff --git a/extern/libpng/tests/pngunknown-sTER b/extern/libpng/tests/pngunknown-sTER
new file mode 100755
index 0000000000..59c5ecd54f
--- /dev/null
+++ b/extern/libpng/tests/pngunknown-sTER
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict sTER=if-safe "${srcdir}/pngtest.png"
diff --git a/extern/libpng/tests/pngunknown-save b/extern/libpng/tests/pngunknown-save
new file mode 100755
index 0000000000..21412c42a6
--- /dev/null
+++ b/extern/libpng/tests/pngunknown-save
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict default=save "${srcdir}/pngtest.png"
diff --git a/extern/libpng/tests/pngunknown-vpAg b/extern/libpng/tests/pngunknown-vpAg
new file mode 100755
index 0000000000..04f07b69a3
--- /dev/null
+++ b/extern/libpng/tests/pngunknown-vpAg
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict vpAg=if-safe "${srcdir}/pngtest.png"
diff --git a/extern/libpng/tests/pngvalid-gamma-16-to-8 b/extern/libpng/tests/pngvalid-gamma-16-to-8
new file mode 100755
index 0000000000..074945d310
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-gamma-16-to-8
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-16-to-8
diff --git a/extern/libpng/tests/pngvalid-gamma-alpha-mode b/extern/libpng/tests/pngvalid-gamma-alpha-mode
new file mode 100755
index 0000000000..b16e8abc4e
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-gamma-alpha-mode
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-alpha-mode
diff --git a/extern/libpng/tests/pngvalid-gamma-background b/extern/libpng/tests/pngvalid-gamma-background
new file mode 100755
index 0000000000..3dbf58d8a0
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-gamma-background
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-background
diff --git a/extern/libpng/tests/pngvalid-gamma-expand16-alpha-mode b/extern/libpng/tests/pngvalid-gamma-expand16-alpha-mode
new file mode 100755
index 0000000000..4fa10bde27
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-gamma-expand16-alpha-mode
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-alpha-mode --expand16
diff --git a/extern/libpng/tests/pngvalid-gamma-expand16-background b/extern/libpng/tests/pngvalid-gamma-expand16-background
new file mode 100755
index 0000000000..ad9a91762b
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-gamma-expand16-background
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-background --expand16
diff --git a/extern/libpng/tests/pngvalid-gamma-expand16-transform b/extern/libpng/tests/pngvalid-gamma-expand16-transform
new file mode 100755
index 0000000000..5fd1f280ba
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-gamma-expand16-transform
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-transform --expand16
diff --git a/extern/libpng/tests/pngvalid-gamma-sbit b/extern/libpng/tests/pngvalid-gamma-sbit
new file mode 100755
index 0000000000..6ca08e9e34
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-gamma-sbit
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-sbit
diff --git a/extern/libpng/tests/pngvalid-gamma-threshold b/extern/libpng/tests/pngvalid-gamma-threshold
new file mode 100755
index 0000000000..3fe4edf77a
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-gamma-threshold
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-threshold
diff --git a/extern/libpng/tests/pngvalid-gamma-transform b/extern/libpng/tests/pngvalid-gamma-transform
new file mode 100755
index 0000000000..3fa62c688a
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-gamma-transform
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-transform
diff --git a/extern/libpng/tests/pngvalid-progressive-interlace-standard b/extern/libpng/tests/pngvalid-progressive-interlace-standard
new file mode 100755
index 0000000000..a8cdf9e1a3
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-progressive-interlace-standard
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --standard --progressive-read --interlace
diff --git a/extern/libpng/tests/pngvalid-progressive-size b/extern/libpng/tests/pngvalid-progressive-size
new file mode 100755
index 0000000000..868d6dcc32
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-progressive-size
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --size --progressive-read
diff --git a/extern/libpng/tests/pngvalid-progressive-standard b/extern/libpng/tests/pngvalid-progressive-standard
new file mode 100755
index 0000000000..bf7e5c1c2c
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-progressive-standard
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --standard --progressive-read
diff --git a/extern/libpng/tests/pngvalid-standard b/extern/libpng/tests/pngvalid-standard
new file mode 100755
index 0000000000..a89b884245
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-standard
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --standard
diff --git a/extern/libpng/tests/pngvalid-transform b/extern/libpng/tests/pngvalid-transform
new file mode 100755
index 0000000000..c7536aeb89
--- /dev/null
+++ b/extern/libpng/tests/pngvalid-transform
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --transform

From 6c48eb3d5c9cab2eaf9e242dc56b6a5db1c67174 Mon Sep 17 00:00:00 2001
From: Colby Klein <shakesoda@gmail.com>
Date: Tue, 23 Jun 2020 16:58:00 -0700
Subject: [PATCH 55/65] Fix compile on raspberry pi 4/A72

Game runs pretty close to fine, needed to use system libpng and haven't
attempted to use ffmpeg, however.

I'm seeing in the 50fps range in gameplay with no performance tweaks
but having set -mtune=cortex-a72. There's a lot of perf opportunities,
so consistent 60 is certainly within reason without too much pain.
---
 src/CMakeData-arch.cmake                |  6 ++----
 src/CMakeLists.txt                      | 22 +++++++++++++++++-----
 src/archutils/Common/PthreadHelpers.cpp |  3 +++
 src/archutils/Unix/Backtrace.cpp        | 11 +++++++++++
 4 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/src/CMakeData-arch.cmake b/src/CMakeData-arch.cmake
index 896506fb50..b8bd4682d6 100644
--- a/src/CMakeData-arch.cmake
+++ b/src/CMakeData-arch.cmake
@@ -231,14 +231,12 @@ if(NOT APPLE)
                   "arch/Lights/LightsDriver_Linux_PIUIO.cpp"
                   "arch/Lights/LightsDriver_Linux_PIUIO_Leds.cpp"
                   "arch/Lights/LightsDriver_Linux_ITGIO.cpp"
-                  "arch/Lights/LightsDriver_LinuxWeedTech.cpp"
-                  "arch/Lights/LightsDriver_LinuxParallel.cpp")
+                  "arch/Lights/LightsDriver_LinuxWeedTech.cpp")
       list(APPEND SMDATA_ARCH_LIGHTS_HPP
                   "arch/Lights/LightsDriver_Linux_PIUIO.h"
                   "arch/Lights/LightsDriver_Linux_PIUIO_Leds.h"
                   "arch/Lights/LightsDriver_Linux_ITGIO.h"
-                  "arch/Lights/LightsDriver_LinuxWeedTech.h"
-                  "arch/Lights/LightsDriver_LinuxParallel.h")
+                  "arch/Lights/LightsDriver_LinuxWeedTech.h")
       if(WITH_PARALLEL_PORT)
         list(APPEND SMDATA_ARCH_LIGHTS_SRC
                     "arch/Lights/LightsDriver_LinuxParallel.cpp")
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 398e3e78b1..97ed7617b4 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -142,8 +142,12 @@ if(WITH_SSE2)
     if(SM_WIN32_ARCH MATCHES "x86")
       set(SM_COMPILE_FLAGS "${SM_COMPILE_FLAGS} /arch:SSE2")
     endif()
-  else()
+  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "x86")
     set(SM_COMPILE_FLAGS "${SM_COMPILE_FLAGS} -msse2")
+  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64")
+    set(SM_COMPILE_FLAGS "${SM_COMPILE_FLAGS} -mtune=cortex-a72")
+  else()
+    message("Unrecognized host processor type")
   endif()
 endif()
 
@@ -332,9 +336,14 @@ else() # Linux
     sm_add_compile_definition("${SM_EXE_NAME}" CRASH_HANDLER)
     if(LINUX)
       # used only in the ArchHooks_Unix.cpp file
-      sm_add_compile_definition("${SM_EXE_NAME}" BACKTRACE_METHOD_X86_LINUX)
-      sm_add_compile_definition("${SM_EXE_NAME}"
+      if(CMAKE_SYSTEM_PROCESSOR MATCHES "x86" OR CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64")
+        sm_add_compile_definition("${SM_EXE_NAME}" BACKTRACE_METHOD_X86_LINUX)
+        sm_add_compile_definition("${SM_EXE_NAME}"
                                 BACKTRACE_METHOD_TEXT="x86 custom backtrace")
+      else()
+        sm_add_compile_definition("${SM_EXE_NAME}"
+                                BACKTRACE_METHOD_TEXT="no backtrace")
+      endif()
       sm_add_compile_definition(
         "${SM_EXE_NAME}" BACKTRACE_LOOKUP_METHOD_TEXT="backtrace_symbols")
       if(${DL_FOUND})
@@ -351,12 +360,15 @@ else() # Linux
 
     message("Host processor is ${CMAKE_SYSTEM_PROCESSOR}")
     if(CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64")
-      message("Host processor is 64bit")
+      message("Host processor is 64bit X86")
       sm_add_compile_definition("${SM_EXE_NAME}" CPU_X86_64)
     elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "x86"
            OR CMAKE_SYSTEM_PROCESSOR MATCHES "i686")
-      message("Host processor is 32bit")
+      message("Host processor is 32bit X86")
       sm_add_compile_definition("${SM_EXE_NAME}" CPU_X86)
+    elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64")
+      message("Host processor is 64bit ARM")
+      sm_add_compile_definition("${SM_EXE_NAME}" CPU_AARCH64)
     else()
       message("Unrecognized host processor type")
     endif()
diff --git a/src/archutils/Common/PthreadHelpers.cpp b/src/archutils/Common/PthreadHelpers.cpp
index 543f70c55a..05eec07045 100644
--- a/src/archutils/Common/PthreadHelpers.cpp
+++ b/src/archutils/Common/PthreadHelpers.cpp
@@ -244,6 +244,9 @@ bool GetThreadBacktraceContext( uint64_t ThreadID, BacktraceContext *ctx )
 	ctx->PC = (void *)ptrace( PTRACE_PEEKUSER, pid_t(ThreadID), (void *)(PT_NIP<<2), 0 );
 	if( errno )
 		return false;
+#elif defined(CPU_AARCH64)
+	// NYI
+	return false;
 #else
 #error GetThreadBacktraceContext: which arch?
 #endif
diff --git a/src/archutils/Unix/Backtrace.cpp b/src/archutils/Unix/Backtrace.cpp
index fbf9a1c4d3..b650e3b415 100644
--- a/src/archutils/Unix/Backtrace.cpp
+++ b/src/archutils/Unix/Backtrace.cpp
@@ -398,6 +398,12 @@ void GetSignalBacktraceContext( BacktraceContext *ctx, const ucontext_t *uc )
 	ctx->sp = (void *) uc->uc_mcontext.gregs[REG_RSP];
 	ctx->pid = GetCurrentThreadId();
 }
+#elif defined(CPU_AARCH64)
+void GetSignalBacktraceContext( BacktraceContext *ctx, const ucontext_t *uc )
+{
+	// NYI
+}
+
 #else
 #error
 #endif
@@ -740,6 +746,11 @@ void GetBacktrace( const void **buf, size_t size, const BacktraceContext *ctx )
 #warning Undefined BACKTRACE_METHOD_*
 void InitializeBacktrace() { }
 
+void GetSignalBacktraceContext( BacktraceContext *ctx, const ucontext_t *uc )
+{
+	// NYI
+}
+
 void GetBacktrace( const void **buf, size_t size, const BacktraceContext *ctx )
 {
     buf[0] = BACKTRACE_METHOD_NOT_AVAILABLE;

From c57279f6b8e1c321cc8ceb83f9a91c4ab987a06c Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Thu, 25 Jun 2020 03:58:57 -0400
Subject: [PATCH 56/65] allow <pre> HTML elements in Luadoc via Lua.xsd

MDN's web docs describe the "HTML <pre> elements represents preformatted
text which is to be presented exactly as written in the HTML file."

It's handy for formatting multiline code examples in
LuaDocumentation.xml.
---
 Docs/Luadoc/Lua.xsd |  1 +
 Docs/Luadoc/Lua.xsl | 18 +++++++++++++-----
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/Docs/Luadoc/Lua.xsd b/Docs/Luadoc/Lua.xsd
index 3edd27c34f..7b5954af5b 100644
--- a/Docs/Luadoc/Lua.xsd
+++ b/Docs/Luadoc/Lua.xsd
@@ -89,6 +89,7 @@
 			<xs:element name="Link" type="Link" />
 			<!-- HTML elements we want to let through. -->
 			<xs:element name="code" />
+			<xs:element name="pre" />
 			<xs:element name="br" />
 			<xs:element name="del" />
 		</xs:choice>
diff --git a/Docs/Luadoc/Lua.xsl b/Docs/Luadoc/Lua.xsl
index 64986a12d7..b655c3a95e 100644
--- a/Docs/Luadoc/Lua.xsl
+++ b/Docs/Luadoc/Lua.xsl
@@ -106,7 +106,7 @@
 				font-family: monospace;
 			}
 			.descriptionText {
-				text-indent: 2em;
+				padding-left: 2em;
 				margin-top: 0;
 				margin-bottom: 0;
 			}
@@ -169,7 +169,7 @@
 				var listid = 'list_' + id;
 				var img = document.getElementById( imgid );
 				var list = document.getElementById( listid );
-			
+
 				img.setAttribute( 'src', 'open.gif' );
 				list.style.display = 'block';
 			}
@@ -184,7 +184,7 @@
 				var listid = 'list_' + id;
 				var img = document.getElementById( imgid );
 				var list = document.getElementById( listid );
-				
+
 				if( img.getAttribute('src') == 'closed.gif' )
 				{
 					img.setAttribute( 'src', 'open.gif' );
@@ -200,7 +200,7 @@
 		<link rel="icon" type="image/vnd.microsoft.icon" href="./favicon.ico"/>
 		</head>
 		<body>
-			<xsl:apply-templates />
+			<xsl:apply-templates />\
 		</body>
 	</html>
 </xsl:template>
@@ -648,7 +648,7 @@
 				<xsl:sort select="@name" />
 				<tr class="code">
 					<td>
-					
+
 					<xsl:value-of select="@name" />
 					</td>
 					<td><xsl:value-of select="@value" /></td>
@@ -670,6 +670,14 @@
 		</xsl:apply-templates>
 	</code>
 </xsl:template>
+<xsl:template match="sm:pre">
+	<xsl:param name="curclass" />
+	<pre>
+		<xsl:apply-templates>
+			<xsl:with-param name="curclass" select="$curclass" />
+		</xsl:apply-templates>
+	</pre>
+</xsl:template>
 <xsl:template match="sm:br"><br /></xsl:template>
 <xsl:template match="sm:del">
 	<del>

From 7804efb1030ea4e56008ef2fc96d140c9112785d Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Thu, 25 Jun 2020 04:24:24 -0400
Subject: [PATCH 57/65] update GlobalFunctions prose in LuaDocumentation

Expand and clarify the prose for many gloabl Lua functions described in
in LuaDocumentation.xml.

Get Lua.xml's GlobalFunctions listing current with 5_1-new.  Remove old
global functions (those moved to 5.1's "legacy" theme) from Lua.xml.
---
 Docs/Luadoc/Lua.xml              |  53 ++++--
 Docs/Luadoc/LuaDocumentation.xml | 311 ++++++++++++++++++++-----------
 2 files changed, 247 insertions(+), 117 deletions(-)

diff --git a/Docs/Luadoc/Lua.xml b/Docs/Luadoc/Lua.xml
index bec2e01f46..cbcd85d52b 100644
--- a/Docs/Luadoc/Lua.xml
+++ b/Docs/Luadoc/Lua.xml
@@ -9,6 +9,8 @@
 		<Function name='AreStagePlayerModsForced'/>
 		<Function name='AreStageSongModsForced'/>
 		<Function name='ArgsIfPlayerJoinedOrNil'/>
+		<Function name='BGFitChoiceExample'/>
+		<Function name='BGFitInputActor'/>
 		<Function name='Basename'/>
 		<Function name='BoostColor'/>
 		<Function name='Brightness'/>
@@ -24,6 +26,11 @@
 		<Function name='ComboPerRow'/>
 		<Function name='ComboTransformCommand'/>
 		<Function name='ComboUnderField'/>
+		<Function name='ConfAspectRatio'/>
+		<Function name='ConfDisplayMode'/>
+		<Function name='ConfDisplayResolution'/>
+		<Function name='ConfFullscreenType'/>
+		<Function name='ConfRefreshRate'/>
 		<Function name='ConnectToServer'/>
 		<Function name='CourseDifficultyToLocalizedString'/>
 		<Function name='CourseTypeToLocalizedString'/>
@@ -42,11 +49,13 @@
 		<Function name='FormatNumberAndSuffix'/>
 		<Function name='FormatPercentScore'/>
 		<Function name='GameCompatibleModes'/>
-		<Function name='GamePrefDefaultFail'/>
+		<Function name='GameOverOrContinue'/>
+		<Function name='GameplayMargins'/>
 		<Function name='GetCodeForGame'/>
 		<Function name='GetCoursesToShowRanking'/>
 		<Function name='GetCustomDifficulty'/>
 		<Function name='GetDefaultOptionLines'/>
+		<Function name='GetDisplayRatesForResolution'/>
 		<Function name='GetEditModeSubScreens'/>
 		<Function name='GetExtraColorThreshold'/>
 		<Function name='GetGamePref'/>
@@ -55,6 +64,7 @@
 		<Function name='GetGamePrefN'/>
 		<Function name='GetGradeFromPercent'/>
 		<Function name='GetLifeDifficulty'/>
+		<Function name='GetOptionsListMapping'/>
 		<Function name='GetPlayerOrMachineProfile'/>
 		<Function name='GetProTiming'/>
 		<Function name='GetRandomSongBackground'/>
@@ -63,6 +73,7 @@
 		<Function name='GetScreenAspectRatio'/>
 		<Function name='GetServerName'/>
 		<Function name='GetSongBackground'/>
+		<Function name='GetSpeedModeAndValueFromPoptions'/>
 		<Function name='GetTapPosition'/>
 		<Function name='GetThemeAspectRatio'/>
 		<Function name='GetThemePref'/>
@@ -87,6 +98,7 @@
 		<Function name='InitGamePrefs'/>
 		<Function name='InitUserPrefs'/>
 		<Function name='IsArcade'/>
+		<Function name='IsCourse'/>
 		<Function name='IsFreePlay'/>
 		<Function name='IsGame'/>
 		<Function name='IsHome'/>
@@ -118,12 +130,14 @@
 		<Function name='OldStyleStringToDifficulty'/>
 		<Function name='OptionRowProTiming'/>
 		<Function name='OptionRowScreenFilter'/>
+		<Function name='OptionsNavigationMode'/>
 		<Function name='OptionsRandomJukebox'/>
 		<Function name='OptionsRowTest'/>
 		<Function name='OptionsWeight'/>
 		<Function name='PeakComboAwardToLocalizedString'/>
 		<Function name='PlayModeToLocalizedString'/>
 		<Function name='PlayerColor'/>
+		<Function name='PlayerDarkColor'/>
 		<Function name='PlayerNumberToLocalizedString'/>
 		<Function name='PlayerNumberToString'/>
 		<Function name='PlayerScoreColor'/>
@@ -137,7 +151,6 @@
 		<Function name='ReadGamePrefFromFile'/>
 		<Function name='ReadPrefFromFile'/>
 		<Function name='ReportStyle'/>
-		<Function name='ResetDefaultFail'/>
 		<Function name='ResolveRelativePath'/>
 		<Function name='RoutineSkinP1'/>
 		<Function name='RoutineSkinP2'/>
@@ -146,7 +159,10 @@
 		<Function name='SaveProfileCustom'/>
 		<Function name='SaveScreenshot'/>
 		<Function name='ScoreKeeperClass'/>
+		<Function name='ScreenColor'/>
 		<Function name='ScreenMetric'/>
+		<Function name='ScreenSelectStyleChoices'/>
+		<Function name='ScreenSelectStylePositions'/>
 		<Function name='ScreenString'/>
 		<Function name='Second'/>
 		<Function name='SecondsToHHMMSS'/>
@@ -158,18 +174,13 @@
 		<Function name='SelectMusicOrCourse'/>
 		<Function name='SelectProfileKeys'/>
 		<Function name='Serialize'/>
-		<Function name='SetFail'/>
 		<Function name='SetGamePref'/>
 		<Function name='SetThemePref'/>
 		<Function name='SetUserPref'/>
 		<Function name='ShowHoldJudgments'/>
 		<Function name='ShowStandardDecoration'/>
-		<Function name='SongMeterDisplayCommand'/>
-		<Function name='SongMeterDisplayX'/>
-		<Function name='SongMeterDisplayY'/>
-		<Function name='SongPrefFail'/>
 		<Function name='SortOrderToLocalizedString'/>
-		<Function name='SpeedModIncMultiple'/>
+		<Function name='SpeedModIncLarge'/>
 		<Function name='SpeedModIncSize'/>
 		<Function name='SpeedMods'/>
 		<Function name='StageAwardToLocalizedString'/>
@@ -190,9 +201,9 @@
 		<Function name='ToEnumShortString'/>
 		<Function name='Trace'/>
 		<Function name='TrailToCustomDifficulty'/>
+		<Function name='TwoPartSelection'/>
 		<Function name='URLEncode'/>
 		<Function name='UnlockRewardTypeToLocalizedString'/>
-		<Function name='update_centering'/>
 		<Function name='Var'/>
 		<Function name='VersionDate'/>
 		<Function name='VersionTime'/>
@@ -203,25 +214,33 @@
 		<Function name='WriteGamePrefToFile'/>
 		<Function name='WritePrefToFile'/>
 		<Function name='Year'/>
+		<Function name='alias_one'/>
+		<Function name='alias_set'/>
 		<Function name='approach'/>
 		<Function name='assert'/>
+		<Function name='check_stop_course_early'/>
 		<Function name='clamp'/>
 		<Function name='class'/>
 		<Function name='collectgarbage'/>
 		<Function name='color'/>
 		<Function name='commify'/>
+		<Function name='convert_text_to_indented_lines'/>
 		<Function name='convert_xml_bgs'/>
+		<Function name='create_bezier'/>
+		<Function name='create_spline'/>
 		<Function name='dofile'/>
 		<Function name='error'/>
 		<Function name='fapproach'/>
 		<Function name='find_missing_strings_in_theme_translations'/>
+		<Function name='force_to_range'/>
+		<Function name='foreach_by_sorted_keys'/>
 		<Function name='foreach_ordered'/>
 		<Function name='gcinfo'/>
+		<Function name='get_music_file_length'/>
+		<Function name='get_sound_driver_list'/>
 		<Function name='getenv'/>
 		<Function name='getfenv'/>
 		<Function name='getmetatable'/>
-		<Function name='get_music_file_length'/>
-		<Function name='get_sound_driver_list'/>
 		<Function name='ipairs'/>
 		<Function name='ivalues'/>
 		<Function name='join'/>
@@ -230,23 +249,29 @@
 		<Function name='load'/>
 		<Function name='loadfile'/>
 		<Function name='loadstring'/>
+		<Function name='make_camel_aliases'/>
 		<Function name='mbstrlen'/>
 		<Function name='module'/>
 		<Function name='multiapproach'/>
+		<Function name='new_numpad_entry'/>
 		<Function name='newproxy'/>
 		<Function name='next'/>
+		<Function name='oitg_zoom_mode_actor'/>
 		<Function name='pairs'/>
+		<Function name='pause_controller_actor'/>
 		<Function name='pcall'/>
 		<Function name='pname'/>
 		<Function name='print'/>
 		<Function name='rawequal'/>
 		<Function name='rawget'/>
 		<Function name='rawset'/>
+		<Function name='rec_count_children'/>
 		<Function name='rec_print_children'/>
 		<Function name='rec_print_table'/>
 		<Function name='require'/>
 		<Function name='round'/>
 		<Function name='scale'/>
+		<Function name='scale_to_fit'/>
 		<Function name='select'/>
 		<Function name='setenv'/>
 		<Function name='setfenv'/>
@@ -254,12 +279,18 @@
 		<Function name='split'/>
 		<Function name='tableshuffle'/>
 		<Function name='tableslice'/>
+		<Function name='thified_curstage_index'/>
 		<Function name='tobool'/>
 		<Function name='tonumber'/>
 		<Function name='tostring'/>
 		<Function name='type'/>
 		<Function name='unpack'/>
+		<Function name='update_centering'/>
+		<Function name='width_clip_limit_text'/>
+		<Function name='width_clip_text'/>
+		<Function name='width_limit_text'/>
 		<Function name='wrap'/>
+		<Function name='wrapped_index'/>
 		<Function name='xpcall'/>
 	</GlobalFunctions>
 	<Classes>
diff --git a/Docs/Luadoc/LuaDocumentation.xml b/Docs/Luadoc/LuaDocumentation.xml
index 765ecc3aaa..d063c59940 100644
--- a/Docs/Luadoc/LuaDocumentation.xml
+++ b/Docs/Luadoc/LuaDocumentation.xml
@@ -28,30 +28,54 @@ save yourself some time, copy this for undocumented things:
 <Documentation xmlns='http://www.stepmania.com' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://www.stepmania.com Lua.xsd'>
 <!-- Global functions -->
 <GlobalFunctions>
+	<Description>
+		Many global functions are available when scripting with Lua for StepMania.<br />
+		Some, like <Link class='GLOBAL' function='collectgarbage' />, are core functions of Lua 5.1's <a href="https://www.lua.org/manual/5.1/manual.html#5.1" target="_blank" rel="noopener noreferrer">basic Library</a>.<br />
+		Others, like <Link class='GLOBAL' function='Basename' />, are defined in the StepMania engine's C++ but made available to Lua.<br />
+	  And others, like <Link class='GLOBAL' function='DeepCopy' />, are defined in the _fallback theme's Lua files.<br />
+		When scripting with StepMania, keep in mind that if you do not scope your functions (and variables) using the <code>local</code> keyword, they will be global.
+	</Description>
+	<Function name='AllowOptionsMenu' theme='_fallback' return='bool' arguments=''>
+		[03 Gameplay.lua] Returns <code>false</code> if the player should be disallowed from entering the options menu from ScreenSelectMusic (i.e. during <Link class='GameState' function='IsAnExtraStage'>an ExtraStage</Link> or when the <Link class='ENUM' function='PlayMode' /> is Oni).  Returns <code>true</code> otherwise.
+	</Function>
 	<Function name='Alpha' theme='_fallback' return='color' arguments='color c, float percent'>
-		[02 Colors.lua] Returns a <code>color</code> with the specified alpha.
+		[02 Colors.lua] Returns a <code>color</code> with HSV values matching <code>c</code> and alpha set to <code>percent</code>, where <code>percent</code> is in the range <code>0</code>..<code>1</code>.
 	</Function>
 	<Function name='approach' return='float' arguments='float current, float goal, float speed'>
 		Use this to make a current value approach a goal value at the given speed.  Speed must not be negative.  The value will not overshoot the goal.<br />
 		Note:  When you see the error "approach: speed 1 is negative." it means that the speed value passed was negative.  The 1 is there because approach and multiapproach use the same internal function and can be ignored when using approach.
 	</Function>
 	<Function name='ArbitrarySpeedMods' theme='_fallback' return='LuaOptionRow' arguments=''>
-		[03 CustomSpeedMods.lua]
+		[03 CustomSpeedMods.lua] Returns an <Link class='OptionRow' /> of speed mod choices generated from the comma-delimited list in <em>SpeedMods.txt</em> in the root of the current Profile directory (player if available, machine otherwise).
 	</Function>
 	<Function name='AreStagePlayerModsForced' theme='_fallback' return='bool' arguments=''>
-		[02 StageMods.lua]
+		[02 StageMods.lua] Returns <code>true</code> if player modifiers should be forced.  This is effectively the negation of <Link class='GLOBAL' function='AllowOptionsMenu' />.
 	</Function>
 	<Function name='AreStageSongModsForced' theme='_fallback' return='bool' arguments=''>
-		[02 StageMods.lua]
+		[02 StageMods.lua] Returns <code>true</code> if song modifiers should be forced (i.e. during <Link class='GameState' function='IsAnExtraStage'>an ExtraStage</Link>, or when the <Link class='ENUM' function='PlayMode' /> is Oni, Battle, or Rave).
 	</Function>
 	<Function name='assert' return='various' arguments='LuaReference v, string sAssertMessage'>
-		Issues an error when <code>v</code> is <code>false</code> (or <code>nil</code>). Returns all arguments otherwise. <code>sAssertMessage</code> is an optional error message (the default is "assertion failed!").
+		Issues an error when <code>v</code> is <code>false</code> (or <code>nil</code>). Returns all arguments otherwise. <code>sAssertMessage</code> is an optional error message (the default is "assertion failed!").<br />
+		<code>assert</code> is a core function of Lua's basic library; see the Lua manual for more details.
+	</Function>
+	<Function name='ArgsIfPlayerJoinedOrNil' theme='_fallback' return='various, various' arguments='various arg1, various arg2'>
+		[02 Utilities.lua] Returns two results.<br />
+		If P1 <Link class='GameState' function='IsSideJoined'>is joined</Link>, the first return value will be <code>arg1</code>, and <code>nil</code> otherwise.<br />
+		If P2 is joined, the second return value will be <code>arg2</code>, and <code>nil</code> otherwise.
+	</Function>
+	<Function name='BGFitChoiceExample' theme='_fallback' return='ActorFrame' arguments='table params'>
+		[04 SetBGFitHelpers.lua] Returns an ActorFrame containing examples of how a given background image (with set aspect ratio) will appear in a particular <Link class='ENUM' function='BackgroundFitMode' />.<br />
+		The _fallback theme uses this to visually represent choices for ScreenSetBGFit, intended to help players choose a BackgroundFitMode preference.
+	</Function>
+	<Function name='BGFitInputActor' theme='_fallback' return='ActorFrame' arguments='table choices, function LoseFocus, function GainFocus'>
+		[04 SetBGFitHelpers.lua] Returns an ActorFrame with an <Link class='Screen' Function='AddInputCallback'>InputCallback</Link> attached.<br />
+		The _fallback theme uses this to manage input on ScreenSetBGFit, intended to help players choose a <Link class='ENUM' function='BackgroundFitMode' /> preference.
 	</Function>
 	<Function name='Basename' return='string' arguments='string path'>
-		Returns the base name of file path.
+		Returns the last named component of <code>path</code>.  For example, passing in <code>"/path/to/file.txt"</code> will return <code>"file.txt"</code>, while <code>"/path/to/some/directory/"</code> will return <code>"directory"</code>.
 	</Function>
 	<Function name='BoostColor' theme='_fallback' return='color' arguments='color c, float fBoost'>
-		[02 Colors.lua] Boosts the specified color by multiplying its values by <code>fBoost</code>.
+		[02 Colors.lua] Returns the color that results from multiplying <code>c</code>'s R, G, and B values by <code>fBoost</code>.
 	</Function>
 	<Function name='Brightness' theme='_fallback' return='color' arguments='color c, float percent'>
 		[02 Colors.lua] Modifies the brightness of the specified color.
@@ -71,7 +95,8 @@ save yourself some time, copy this for undocumented things:
 		Closes any connection to an online server.
 	</Function>
 	<Function name='collectgarbage' return='void' arguments='string opt, float arg'>
-		A generic interface to Lua's garbage collector. Performs different functions based on the value of <code>opt</code>.
+		A generic interface to Lua's garbage collector. Performs different functions based on the value of <code>opt</code>.<br />
+		<code>collectgarbage</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='color' return='color' arguments='string color'>
 		Returns a color from a string. <code>color</code> can be in hex (<code>"#FFFFFFFF"</code>) or 0..1 values (<code>"1.0,1.0,1.0,1.0"</code>), in RGBA order.
@@ -86,10 +111,10 @@ save yourself some time, copy this for undocumented things:
 		[02 Colors.lua] Returns a midtone of the color. (Specifically <code>c[1]/1.5, c[2]/1.5, c[3]/1.5, c[4]</code>)
 	</Function>
 	<Function name='ColorToHex' theme='_fallback' return='string' arguments='color c'>
-		[02 Colors.lua] Returns a hex representation for the specified color.
+		[02 Colors.lua] Accepts a color and returns the hex representation.  For example, passing in <code>{1, 0, 0.4, 1}</code> will return <code>"FF0066FF"</code>.
 	</Function>
 	<Function name='ColorToHSV' theme='_fallback' return='table' arguments='color c'>
-		[02 Colors.lua] Takes in a color and returns a table with the HSV values.
+		[02 Colors.lua]  Accepts a color and returns a table with the HSV values, indexed by <code>Hue</code>, <code>Sat</code>, <code>Value</code>, and <code>Alpha</code>.
 	</Function>
 	<Function name='ComboContinue' theme='_fallback' return='TapNoteScore' arguments=''>
 		[03 Gameplay.lua] Determines what TapNoteScore allows for continuing the combo.
@@ -101,10 +126,8 @@ save yourself some time, copy this for undocumented things:
 		[03 Gameplay.lua] Determines if combo should be per row (Jump = 1) or per column (Jump = 2).
 	</Function>
 	<Function name='ComboTransformCommand' theme='_fallback' return='void' arguments='Actor self, params p'>
-		[02 Other.lua] The combo trasform command.
-	</Function>
-	<Function name='ComboUnderField' theme='_fallback' return='bool' arguments=''>
-		[03 Gameplay.lua] Returns the <code>UserPrefComboUnderField</code> user preference value.
+		[02 Other.lua] Defines the transform function used to position player combo during gameplay.  <code>params</code> will contain two boolean values indexed by <code>bReverse</code> and <code>bCentered</code>.<br />
+		Not intended to be called directly by themes.
 	</Function>
 	<Function name='commify' return='string' arguments='string number, string comma, string dot'>
 		This will take the number and insert a comma every three digits, as normal in English for writing large numbers.<br />
@@ -118,10 +141,18 @@ save yourself some time, copy this for undocumented things:
 	<Function name='ConnectToServer' return='bool' arguments='string sAddress'>
 		Tries to connect to the server at <code>sAddress</code>.
 	</Function>
+	<Function name='CourseDifficultyToLocalizedString' return='string' arguments='Difficulty d'>
+		Returns <Link class='ENUM' function='Difficulty' /> <code>d</code> localized for the current language using strings defined under <code>[CourseDifficulty]</code>.
+	</Function>
+	<Function name='CourseTypeToLocalizedString' return='string' arguments='CourseType ct'>
+		Returns <Link class='ENUM' function='CourseType' /> <code>ct</code> localized for the current language using strings defined under <code>[CourseType]</code>.
+	</Function>
+	<Function name='convert_text_to_indented_lines' theme='_fallback' return='table' arguments='BitmapText text, int indent, float width, float text_zoom'>
+		[02 Utilities.lua] Utillity function used to format log output for presenting on-screen.  <code>indent</code> is the number of pixels to indent lines.  <code>width</code> is the width in pixels that lines should be constrained to.
+	</Function>
 	<Function name='convert_xml_bgs' return='' arguments='string dir'>
-		Recursively searches <code>dir</code> for xml files of actors and
-		converts them to equivalent lua files.  See Docs/Themerdocs/XmlToLua.txt
-		for details.
+		Recursively searches <code>dir</code> for xml files of actors and converts them to equivalent lua files.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/XmlToLua.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/XmlToLua.txt</a>.
 	</Function>
 	<Function name='create_bezier' return='RageBezier2D' arguments=''>
 		Creates a RageBezier2D for you to use.  Make sure you destroy the RageBezier2D when you're done with it, or you will have a memory leak.
@@ -138,17 +169,21 @@ save yourself some time, copy this for undocumented things:
 	<Function name='CustomDifficultyToLightColor' theme='_fallback' return='color' arguments='string cd'>
 		[02 Colors.lua]
 	</Function>
+	<Function name='CustomDifficultyToLocalizedString' return='string' arguments='string cd'>
+		Returns <code>cd</code> localized for the current language using strings defined under <code>[CustomDifficulty]</code>.
+	</Function>
 	<Function name='DayOfMonth' return='int' arguments=''>
-		Returns the current day of the month.
+		Returns the current day of the month in the range <code>1</code>-<code>31</code>.
 	</Function>
 	<Function name='DayOfYear' return='int' arguments=''>
-		Returns the current day of the year.
+		Returns the current day of the year in the range <code>0</code>-<code>365</code>.
 	</Function>
 	<Function name='DeepCopy' theme='_fallback' return='table' arguments='table from, table to, table already_copied'>
 		[02 Serialize] Recursively deep-copy a table.
 	</Function>
 	<Function name='dofile' theme='_fallback' return='chunk' arguments='string sFilePath'>
-		[01 base.lua] "Override Lua's dofile to use our <Link function="loadfile">loadfile</Link>."
+		<code>dofile</code> is normally a core function of Lua's basic library.  StepMania overrides this in
+		[01 base.lua] to use <Link function="loadfile">loadfile</Link>, which itself has been overridden.
 	</Function>
 	<Function name='EvalUsesCheckpointsWithJudgments' theme='_fallback' return='bool' arguments=''>
 		[03 Gameplay.lua]
@@ -162,8 +197,8 @@ save yourself some time, copy this for undocumented things:
 	<Function name='find_missing_strings_in_theme_translations' return='' arguments='string theme_name, string master_lang_name'>
 		This function creates files in the theme's Languages folder listing all the strings that have no translation and all the strings that are unused.<br />
 		Strings that do not have an entry in the master language are considered unused.<br />
-		master_lang_name is the name of the ini file that contains the language with all strings used by the theme.<br />
-		Example:  find_missing_strings_in_theme_translations("my_best_theme", "en.ini")
+		<code>master_lang_name</code> is the name of the ini file that contains the language with all strings used by the theme.<br />
+		Example:  find_missing_strings_in_theme_translations( "my_best_theme", "en.ini" )
 	</Function>
 	<Function name='FindSelection' theme='_fallback' return='int' arguments='table list'>
 		[02 Utilities.lua] Return the index of a true value in <code>list</code>.
@@ -172,12 +207,16 @@ save yourself some time, copy this for undocumented things:
 		[02 Utilities.lua] Find a key in <code>tab</code> with the given <code>value</code>.
 	</Function>
 	<Function name='foreach_ordered' theme='_fallback' return='void' arguments='table t, function f'>
-		<code>func</code> takes a key and a value.
+		<code>f</code> takes a key and a value.
+	</Function>
+	<Function name='force_to_range' theme='default' return='float' args='float min, float number, float max'>
 	</Function>
 	<Function name='FormatNumberAndSuffix' return='string' arguments='int num'>
 		Returns the number passed to the function followed by its suffix (&quot;th&quot;, &quot;nd&quot;, and so on).
 	</Function>
-	<!-- FormatNumSongsPlayed -->
+	<Function name='FormatNumSongsPlayed' return='string' arguments='int num'>
+		[02 Other.lua] Concatenates <code>num</code> with " songs played" and returns the resulting string.
+	</Function>
 	<Function name='FormatPercentScore' return='string' arguments='float fPercentDancePoints'>
 		Returns <code>fPercentDancePoints</code> formatted as a percentage.
 	</Function>
@@ -187,6 +226,10 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetCodeForGame' theme='_fallback' return='string' arguments=''>
 		[03 Gameplay.lua]
 	</Function>
+	<Function name='GetCoursesToShowRanking' theme='_fallback' return='string' arguments=''>
+		[02 Other.lua] Returns the value of the <code>CoursesToShowRanking</code> preference if it is not an empty string.<br />
+		Otherwise, returns a comma-delimited set of paths to the .crs files included with StepMania as a string.  This string is hardcoded and does not accurately reflect whether those crs files exist in the filesystem.
+	</Function>
 	<Function name='GetCustomDifficulty' return='string' arguments='StepsType st, Difficulty d, CourseType ct'>
 		Returns the corresponding CustomDifficulty string for a StepsType/Difficulty (/optional CourseType) combination.
 	</Function>
@@ -206,23 +249,20 @@ save yourself some time, copy this for undocumented things:
 		Returns a corresponding <Link class='ENUM' function='Grade' /> for the given percentage.
 	</Function>
 	<Function name='GetLifeDifficulty' return='int' arguments=''>
-		Returns the current Life Difficulty.
+		Returns the current Life difficulty in the range of <code>1</code>-<code>7</code>
 	</Function>
 	<Function name='get_music_file_length' return='float' arguments='string path'>
-		Returns the length of the music file found at path.<br />
-		If you are loading the sound into an ActorSound, ActorSound:get to get its RageSound then use RageSound's get_length function instead to avoid loading the file twice.
+		Returns the length of the music file found at <code>path</code> in seconds.<br />
+		If the file has already been loaded into an ActorSound, use <Link class='ActorSound' function='get' /> to get its <code>RageSound</code>, and then use <Link class='RageSound' function='get_length' /> to avoid loading the file twice.
 	</Function>
 	<Function name='get_sound_driver_list' return='table' arguments=''>
-		Returns a table of the names of the sound drivers available.  If the SoundDriver preference is set to something that is not in this list, StepMania WILL NOT START UP.  Changes to the SoundDriver preference do not take effect until the next time StepMania starts up.
-	</Function>
-	<Function name='GetOSName' return='string' arguments=''>
-		Returns a string representing the name of the operating system being used. (e.g. "Windows", "Linux", "Mac, "Unknown")
+		Returns a table of the names of the sound drivers available.  If the SoundDriver preference is set to something that is not in this list, StepMania will not start up.  Changes to the SoundDriver preference do not take effect until the next time StepMania starts up.
 	</Function>
 	<Function name='GetPlayerOrMachineProfile' theme='_fallback' return='Profile' arguments='PlayerNumber pn'>
 		[02 Utilities.lua] "This returns a profile, preferably a player one. If there isn't one, [it falls] back on the machine profile."
 	</Function>
 	<Function name='GetProTiming' theme='default' return='bool' arguments='PlayerNumber pn'>
-		[03 ThemePrefs.lua] Returns <code>true</code> if player <code>pn</code> is using ProTiming.
+		[03 ThemePrefs.lua] Returns <code>true</code> if player <code>pn</code> is using the <em>ProTiming</em> <Link class='GLOBAL' function='GetUserPref'>UserPref</Link>.
 	</Function>
 	<Function name='GetRandomSongBackground' theme='_fallback' return='string' arguments=''>
 		[02 Utilities.lua] Returns a path to a random song background.
@@ -234,7 +274,7 @@ save yourself some time, copy this for undocumented things:
 		[02 Actor.lua]
 	</Function>
 	<Function name='GetScreenAspectRatio' return='float' arguments=''>
-		Returns the display aspect ratio.
+		Returns the screen display aspect ratio (i.e. the <code>DisplayAspectRatio</code> preference).
 	</Function>
 	<Function name='GetServerName' return='string' arguments=''>
 		Returns the name of the currently connected server.
@@ -242,17 +282,21 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetSongBackground' theme='_fallback' return='string' arguments=''>
 		[02 Utilities.lua] Returns a path to the current songs background.
 	</Function>
-	<Function name='GetTapPosition' theme='_fallback' return='float' arguments=''>
+	<Function name='GetSpeedModeAndValueFromPoptions' theme='_fallback' return='float' arguments=''>
 		[03 Gameplay.lua]
 	</Function>
+	<Function name='GetTapPosition' theme='_fallback' return='int, string' arguments='PlayerNumber pn'>
+		[03 CustomSpeedMods.lua]
+	</Function>
 	<Function name='GetThemeAspectRatio' return='float' arguments=''>
-		Returns the theme's aspect ratio.
+		Returns the theme's aspect ratio.<br />
+		Specifically, this is the result of dividing <code>ScreenWidth</code> by <code>ScreenHeight</code> as each is defined under the theme's <code>[Common]</code> metric.
 	</Function>
 	<Function name='GetThemePref' theme='_fallback' return='various' arguments='string pref'>
-		[03 ThemePrefs.lua] (Alias for <Link class='ThemePrefs' function='Get' />.)
+		[03 ThemePrefs.lua] Alias for <Link class='ThemePrefs' function='Get' />.
 	</Function>
 	<Function name='GetTimingDifficulty' return='int' arguments=''>
-		Returns the current Timing difficulty.
+		Returns the current Timing difficulty in the range of <code>1</code>-<code>9</code>.
 	</Function>
 	<Function name='GetTimeSinceStart' return='float' arguments=''>
 		Returns the current time since the program was started.  Includes time that was spent loading songs.
@@ -288,24 +332,28 @@ save yourself some time, copy this for undocumented things:
 		[03 Gameplay.lua] Returns <code>true</code> if you need to step on hold heads to activate them.
 	</Function>
 	<Function name='HoldTiming' theme='_fallback' return='float' arguments=''>
-		[03 Gameplay.lua] Returns 0 in <code>pump</code> mode, <code>TimingWindowSecondsHold</code> preference value in any other game mode.
+		[03 Gameplay.lua] Returns 0 when the current <Link class='Game' /> is pump.  Returns the <code>TimingWindowSecondsHold</code> preference value in other games.
 	</Function>
 	<Function name='Hour' return='int' arguments=''>
 		Returns the current hour.
 	</Function>
-	<Function name='HSV' theme='_fallback' return='color' arguments='float h, float s, float v'>
-		[02 Colors.lua] Converts a color from HSV values to something StepMania can understand.
-		hue is from <code>0-360</code>, saturation and value are <code>0..1</code>
+	<Function name='HSV' theme='_fallback' return='color' arguments='float hue, float saturation, float value'>
+		[02 Colors.lua] Converts a color from HSV values to something StepMania can understand.<br />
+		<code>hue</code> is from <code>0</code>-<code>360</code><br />
+		<code>saturation</code> and <code>value</code> are <code>0</code>..<code>1</code>
 	</Function>
-	<Function name='HSVA' theme='_fallback' return='color' arguments='float h, float s, float v, float a'>
-		[02 Colors.lua] Converts a color from HSV values with alpha to something StepMania can understand.
-		hue is from <code>0-360</code>, saturation, value, and alpha are <code>0..1</code>
+	<Function name='HSVA' theme='_fallback' return='color' arguments='float hue, float saturation, float value, float alpha'>
+		[02 Colors.lua] Converts a color from HSV values with alpha to something StepMania can understand.<br />
+		hue is from <code>0</code>-<code>360</code><br />
+		<code>saturation</code>, <code>value</code>, and <code>alpha</code> are <code>0</code>..<code>1</code>
 	</Function>
 	<Function name='HSVToColor' theme='_fallback' return='color' arguments='table hsv'>
-		[02 Colors.lua] "Converts a set of HSV values to a color."
+		[02 Colors.lua] Converts a table of HSV values to a color.<br />
+		The <code>hsv</code> table should use indexes <code>Hue</code>, <code>Sat</code>, <code>Value</code>, <code>Alpha</code>.
 	</Function>
 	<Function name='HSVToHex' theme='_fallback' return='string' arguments='table hsv'>
-		[02 Colors.lua] "Takes in a normal color and returns the hex representation. (Adapted from code in LuaBit)"
+		[02 Colors.lua] Accepts a table of HSV values and returns the hex representation.
+		The <code>hsv</code> table should use indexes <code>Hue</code>, <code>Sat</code>, <code>Value</code>, <code>Alpha</code>.
 	</Function>
 	<Function name='Hue' theme='_fallback' return='color' arguments='color c, int newHue'>
 		[02 Colors.lua] Changes the hue of the input color.
@@ -313,17 +361,21 @@ save yourself some time, copy this for undocumented things:
 	<Function name='InitUserPrefs' theme='default' return='void' arguments=''>
 		[03 ThemePrefs.lua] Initializes various user preferences.
 	</Function>
-	<Function name='ipairs' theme='_fallback' return='function' arguments='table t'>
-		[01 base.lua] "Like ipairs(), but returns only values."
+	<Function name='ipairs' theme='_fallback' return='function, table, int' arguments='table t'>
+		Returns three values: an iterator function, the table <code>t</code>, and <code>0</code>,
+		so that the construction <code>for i,v in ipairs(t) do body end</code>
+		will iterate over the pairs (1,t[1]), (2,t[2]), ···, up to the first integer key absent from the table.<br />
+		<code>ipairs</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='IsArcade' theme="_fallback" return='bool' arguments=''>
 		[02 Utilities.lua] Returns <code>true</code> if the coin mode is not set to <Link class='ENUM' function='CoinMode'>CoinMode_Home</Link>.
 	</Function>
-	<Function name='IsEventMode' return='bool' arguments=''>
-		Returns <code>true</code> if Event Mode is turned on.
+	<Function name='IsCourse' theme="_fallback" return='bool' arguments=''>
+		Returns <code>true</code> if the current <Link class='ENUM' function='PlayMode' /> is Nonstop, Oni, or Endless.<br />
+		This is effectively the same as <Link class='GameState' function='IsCourseMode' />.
 	</Function>
 	<Function name='IsFreePlay' theme="_fallback" return='bool' arguments=''>
-		[02 Utilities.lua] Returns <code>true</code> <Link function='IsArcade'>if Arcade</Link> and the coin mode is <Link class='ENUM' function='CoinMode'>CoinMode_Free</Link>.
+		[02 Utilities.lua] Returns <code>true</code> if <Link function='IsArcade'>IsArcade()</Link> and the coin mode is <Link class='ENUM' function='CoinMode'>CoinMode_Free</Link>.
 	</Function>
 	<Function name='IsGame' theme='_fallback' return='bool' arguments='string sGame'>
 		[03 Gameplay.lua] Returns <code>true</code> if the current game is <code>sGame</code>.
@@ -358,6 +410,9 @@ save yourself some time, copy this for undocumented things:
 	<Function name='JudgmentLineToColor' theme='_fallback' return='color' arguments='JudgmentLine jl'>
 		[02 Colors.lua]
 	</Function>
+	<Function name='JudgmentLineToLocalizedString' return='string' arguments='JudgmentLine jl'>
+		Returns <Link class='ENUM' function='JudgmentLine' /> <code>jl</code> localized for the current language using strings defined under <code>[JudgmentLine]</code>.
+	</Function>
 	<Function name='JudgmentLineToStrokeColor' theme='_fallback' return='color' arguments='JudgmentLine jl'>
 		[02 Colors.lua]
 	</Function>
@@ -365,7 +420,7 @@ save yourself some time, copy this for undocumented things:
 		Returns a number linearly interpolated between start and end by percent.
 	</Function>
 	<Function name='lerp_color' return='color' arguments='float percent, color start, color end'>
-		Same as lerp, but for colors.  All channels will reach the end of the interpolation at the same time.
+		Same as <Link class='GLOBAL' function='lerp' />, but for colors.  All channels will reach the end of the interpolation at the same time.
 	</Function>
 	<Function name='LoadActor' return='ActorDef' arguments='string sPath, ...'>
 		Returns an Actor definition for the actor at <code>sPath</code>. If <code>sPath</code> points to a Lua file, any additional arguments will be passed to that script.
@@ -377,7 +432,8 @@ save yourself some time, copy this for undocumented things:
 		[02 ActorDef.lua] Loads an actor with params.
 	</Function>
 	<Function name='loadfile' theme='_fallback' return='chunk' arguments='string sFilePath'>
-		[01 base.lua] "Override Lua's loadfile to use <Link class="lua" function="ReadFile">lua.ReadFile</Link>."
+		<code>loadfile</code> is normally a core function of Lua's basic library.  StepMania overrides this in
+		[01 base.lua] to use <Link class="lua" function="ReadFile">lua.ReadFile</Link>.
 	</Function>
 	<Function name='LoadFallbackB' theme='_fallback' return='ActorDef' arguments=''>
 		[02 ActorDef.lua] Load the fallback BGA for the element that is currently being loaded.
@@ -388,6 +444,9 @@ save yourself some time, copy this for undocumented things:
 	<Function name='LoadSongBackground' theme='_fallback' return='Sprite' arguments=''>
 		[02 Sprite.lua] Returns a Sprite with the current song's background.
 	</Function>
+	<Function name='make_camel_aliases' theme='_fallback' return='' arguments='Actor class'>
+		Iterates over all functions exposed to Lua in <code>class</code>, creating CamelCase aliases for each function.  Not intended to be used by themers.
+	</Function>
 	<Function name='mbstrlen' return='int' arguments='string sString'>
 		Returns the length of the multi-byte character string <code>sString</code>.
 	</Function>
@@ -398,16 +457,17 @@ save yourself some time, copy this for undocumented things:
 		[03 Gameplay.lua] Returns the value to start showing the miss combo at.
 	</Function>
 	<Function name='module' return='void' arguments='string name, ...'>
-		Creates a module. See the Lua manual for more details.
+		Creates a module.<br />
+		<code>module</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='MonthOfYear' return='int' arguments=''>
-		Returns the current month of the year (<code>0</code>-<code>11</code>).
+		Returns the current month of the year in the range <code>0</code>-<code>11</code>.
 	</Function>
 	<Function name='MonthToLocalizedString' return='string' arguments='Month m'>
-		Returns Month <code>m</code> as a localized string.
+		Returns <Link class='ENUM' function='Month' /> <code>m</code> localized for the current language using strings defined under <code>[Month]</code>.
 	</Function>
 	<Function name='MonthToString' return='string' arguments='Month m'>
-		Returns Month <code>m</code> as a string.
+		Returns <Link class='ENUM' function='Month' /> <code>m</code> as a non-localized string.
 	</Function>
 	<Function name='multiapproach' return='table' arguments='table currents, table goals, table speeds, float multiplier'>
 		Similar to approach, but operates on tables of values instead of single values.  This will modify the contents of <code>currents</code> in place, as well as returning <code>currents</code>.<br />
@@ -416,10 +476,10 @@ save yourself some time, copy this for undocumented things:
 		Note:  When you see the error "approach: speed 1 is negative." it means that a speed value passed was negative.  The 1 tells you which entry in the table was invalid.
 	</Function>
 	<Function name='next' return='void' arguments='table t, int index'>
-		"Allows a program to traverse all fields of a table. Its first argument is a
+		Allows a program to traverse all fields of a table. Its first argument is a
 		table and its second argument is an index in this table.
-		<code>next</code> returns the next index of the table and its associated value."
-		See the Lua manual for more details.
+		<code>next</code> returns the next index of the table and its associated value.<br />
+		<code>next</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='OldStyleStringToDifficulty' return='Difficulty' arguments='string dc'>
 		Converts a string such as 'oni' or 'expert' or 'trick' to the appropriate difficulty.
@@ -427,10 +487,12 @@ save yourself some time, copy this for undocumented things:
 	<Function name='OptionRowProTiming' theme='default' return='LuaOptionRow' arguments=''>
 		[03 ThemePrefs.lua] Returns a Lua option row for ProTiming.
 	</Function>
+	<Function name='OptionRowScreenFilter' return='OptionRow' arguments=''></Function>
 	<Function name='pairs' return='function' arguments='table t'>
-		"Returns three values: the <Link class='GLOBAL' function='next' /> function, the table <code>t</code>, and <code>nil</code>,
+		Returns three values: the <Link class='GLOBAL' function='next' /> function, the table <code>t</code>, and <code>nil</code>,
 		so that the construction <code>for k,v in pairs(t) do body end</code>
-		will iterate over all key–value pairs of table <code>t</code>."
+		will iterate over all key–value pairs of table <code>t</code>.<br />
+		<code>pairs</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='PlayerColor' theme='_fallback' return='color' arguments='PlayerNumber pn'>
 		[02 Colors.lua]
@@ -438,6 +500,15 @@ save yourself some time, copy this for undocumented things:
 	<Function name='PlayerScoreColor' theme='_fallback' return='color' arguments='PlayerNumber pn'>
 		[02 Colors.lua]
 	</Function>
+	<Function name='PeakComboAwardToLocalizedString' return='string' arguments='PeakComboAward pma'>
+		Returns <Link class='ENUM' function='PeakComboAward' /> <code>pma</code> localized for the current language using strings defined under <code>[PeakComboAward]</code>.
+	</Function>
+	<Function name='PlayModeToLocalizedString' return='string' arguments='PlayMode pm'>
+		Returns <Link class='ENUM' function='PlayMode' /> <code>pm</code> localized for the current language using strings defined under <code>[PlayMode]</code>.
+	</Function>
+	<Function name='PlayerNumberToLocalizedString' return='string' arguments='PlayerNumber pn'>
+		Returns <Link class='ENUM' function='PlayerNumber' /> <code>pn</code> localized for the current language using strings defined under <code>[PlayerNumber]</code>.
+	</Function>
 	<Function name='pname' theme='_fallback' return='string' arguments='PlayerNumber pn'>
 		[02 Utilities.lua] Converts a PlayerNumber into a short string (e.g. "P1", "P2").
 	</Function>
@@ -448,10 +519,10 @@ save yourself some time, copy this for undocumented things:
 		Returns a formatted percent with the specified <code>num</code>erator and <code>den</code>ominator.
 	</Function>
 	<Function name='print' theme='_fallback' return='void' arguments='string s'>
-		[00 init.lua]
+		[00 init.lua] Alias for <Link class='GLOBAL' function='Trace' />.
 	</Function>
 	<Function name='PrintTable' theme='_fallback' return='void' arguments='table t'>
-		[03 ThemePrefs.lua] Prints a table's contents to the log.
+		[03 ThemePrefs.lua] Prints a table's contents to log.txt using <Link class='GLOBAL' function='Trace'/>.
 	</Function>
 	<Function name='ProductFamily' return='string' arguments=''>
 		Returns the product family. (e.g. "StepMania")
@@ -460,17 +531,23 @@ save yourself some time, copy this for undocumented things:
 		Returns the product ID. (e.g. "StepMania 5")
 	</Function>
 	<Function name='ProductVersion' return='string' arguments=''>
-		Returns the product version.
+		Returns the product version. (e.g. "5.0.11" or "5.1.0" or "5.2-git-96f9771")
+	</Function>
+	<Function name='RadarCategoryToLocalizedString' return='string' arguments='RadarCategory cat'>
+		Returns <Link class='ENUM' function='RadarCategory' /> <code>cat</code> localized for the current language using strings defined under <code>[RadarCategory]</code>.
 	</Function>
 	<Function name='rawequal' return='bool' arguments='various v1, various v2'>
-		"Checks whether <code>v1</code> is equal to <code>v2</code>, without invoking any metamethod."
+		Checks whether <code>v1</code> is equal to <code>v2</code>, without invoking any metamethod.<br />
+		<code>rawequal</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='rawget' return='various' arguments='table t, various index'>
-		"Gets the real value of <code>t[index]</code>, without invoking any metamethod."
+		Gets the real value of <code>t[index]</code>, without invoking any metamethod.<br />
+		<code>rawget</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='rawset' return='table' arguments='table t, int index, various value'>
-		"Sets the real value of <code>t[index]</code> to <code>value</code>, without invoking any metamethod."
-		The modified <code>t</code> is then returned.
+		Sets the real value of <code>t[index]</code> to <code>value</code>, without invoking any metamethod.
+		The modified <code>t</code> is then returned.<br />
+		<code>rawset</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='ResolveRelativePath' theme='_fallback' return='string' arguments='string path, int level, bool optional'>
 		[02 ActorDef.lua] Used internally by LoadActor to resolve a path.  If <code>optional</code> is true, then a nil path is returned instead of emitting an error if no file is found.
@@ -482,18 +559,19 @@ save yourself some time, copy this for undocumented things:
 		[03 UserPreferences2.lua] (internal) Reads the specified user preference from its config file.
 	</Function>
 	<Function name='rec_print_children' theme='_fallback' return='' arguments='ActorFrame a, string indent'>
-		Recursively prints all the children of the actor frame to the log file.  This can be useful for finding out what actors are on a screen or just seeing what the structure of the actor tree looks like.<br />
+		[02 Utilities.lua] Recursively prints all the children of the actor frame to the log file.  This can be useful for finding out what actors are on a screen or just seeing what the structure of the actor tree looks like.<br />
 		<code>indent</code> is an optional argument that will be prepended to every line.
 	</Function>
 	<Function name='rec_print_table' theme='_fallback' return='' arguments='table t, string indent'>
-		Recursively prints all values in the table to the log file in the form "(key_type) key: (value_type) value" so that you know the type of the key and the value.  Useful if you're not sure exactly what is in a table passed as a parameter.<br />
+		[02 Utilities.lua] Recursively prints all values in the table to the log file in the form "(key_type) key: (value_type) value" so that you know the type of the key and the value.  Useful if you're not sure exactly what is in a table passed as a parameter.<br />
 		<code>indent</code> is an optional argument that will be prepended to every line.
 	</Function>
 	<Function name='ReportStyle' return='void' arguments=''>
 		Sends the current style to the server.
 	</Function>
 	<Function name='require' return='void' arguments='string modname'>
-		Loads the specified module. See the Lua manual for more information.
+		Loads the specified module.<br />
+		<code>require</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='round' theme='_fallback' return='int' arguments='float val, int decimal'>
 		[02 Utilities.lua] Round a number.
@@ -508,20 +586,27 @@ save yourself some time, copy this for undocumented things:
 		[02 Colors.lua] Modifies the saturation of the specified color
 	</Function>
 	<Function name='SaveScreenshot' return='bool, string' arguments='PlayerNumber pn, bool compress, bool sign, string prefix, string suffix'>
-		Saves a screenshot.  If pn is nil, saves to the machine's Screenshots dir, otherwise saves to the profile's Screenshots dir.  Saves as jpg if compress is true, or png if compress is false.  The screenshot is signed if sign is true.  prefix and suffix are optional strings to add to the beginning and end of the filename.<br/>
+		Saves a screenshot.  If pn is nil, saves to the machine's Screenshots dir, otherwise saves to the profile's Screenshots dir.  Saves as jpg if compress is true, or png if compress is false.  The screenshot is signed if sign is true.  prefix and suffix are optional strings to add to the beginning and end of the filename.<br />
 		Returns success and full path of the resulting screenshot.
 	</Function>
 	<Function name='scale' return='float' arguments='float x, float low1, float high1, float low2, float high2'>
 		Scales <code>x</code>, originally within <code>low1</code> and <code>high1</code>, to fall between <code>low2</code> and <code>high2</code>.
 	</Function>
+	<Function name='scale_to_fit' theme='default' return='' arguments='Actor a, float width, float height'>
+	</Function>
 	<Function name='ScoreKeeperClass' theme='_fallback' return='string' arguments=''>
 		[03 Gameplay.lua] Returns the primary ScoreKeeper class to use.
 	</Function>
+	<Function name='ScreenColor' theme='default' return='string' arguments='string screen'>
+		[02 Colors.lua]
+	</Function>
 	<Function name='ScreenMetric' theme='_fallback' return='string' arguments='string s'>
-		[00 alias.lua, 02 Other.lua] alias for <Link class='Screen' function='Metric' />.
+		[02 Other.lua] alias for <Link class='Screen' function='Metric' />.
+	</Function>
+	<Function name='ScreenSelectStylePositions' arguments='int count' return='{{float, float}}'>
 	</Function>
 	<Function name='ScreenString' theme='_fallback' return='string' arguments='string s'>
-		[00 alias.lua, 02 Other.lua] alias for <Link class='Screen' function='String' />.
+		[02 Other.lua] alias for <Link class='Screen' function='String' />.
 	</Function>
 	<Function name='Second' return='int' arguments=''>
 		Returns the current second.
@@ -570,15 +655,24 @@ save yourself some time, copy this for undocumented things:
 	<Function name='ShowStandardDecoration' theme='_fallback' return='bool' arguments='string sMetricsName'>
 		[02 ActorDef.lua] Returns <code>true</code> if a decoration should be shown on the current screen or not.
 	</Function>
+	<Function name='SortOrderToLocalizedString' return='string' arguments='SortOrder so'>
+		Returns <Link class='ENUM' function='SortOrder' /> <code>so</code> localized for the current language using strings defined under <code>[SortOrder]</code>.
+	</Function>
 	<Function name='SpeedMods' theme='_fallback' return='LuaOptionRow' arguments=''>
 		[03 CustomSpeedMods.lua] Returns a Lua option row with the custom speed mods defined in SpeedMods.txt.
 	</Function>
 	<Function name='split' theme='_fallback' return='table' arguments='string delimiter, string text'>
 		[02 Utilities.lua] Splits a string at every occurence of <code>delimiter</code>, returning a table of the results.
 	</Function>
+	<Function name='StageAwardToLocalizedString' return='string' arguments='StageAward sa'>
+		Returns <Link class='ENUM' function='StageAward' /> <code>sa</code> localized for the current language using strings defined under <code>[StageAward]</code>.
+	</Function>
 	<Function name='StageToColor' theme='_fallback' return='color' arguments='Stage s'>
 		[02 Colors.lua]
 	</Function>
+	<Function name='StageToLocalizedString' return='string' arguments='Stage i'>
+		Returns <Link class='ENUM' function='Stage' /> <code>i</code> localized for the current language using strings defined under <code>[Stage]</code>.
+	</Function>
 	<Function name='StageToStrokeColor' theme='_fallback' return='color' arguments='Stage s'>
 		[02 Colors.lua]
 	</Function>
@@ -600,58 +694,82 @@ save yourself some time, copy this for undocumented things:
 	<Function name='TableStringLookup' theme='_fallback' return='table' arguments='table t, string group'>
 		[02 Utilities.lua] Look up each value in a table, returning a table with the resulting strings.
 	</Function>
+	<Function name='TapNoteScoreToLocalizedString' return='string' arguments='TapNoteScore tns'>
+		Returns <Link class='ENUM' function='TapNoteScore' /> <code>tns</code> localized for the current language using strings defined under <code>[TapNoteScore]</code>.
+	</Function>
 	<Function name='TextBannerAfterSet' theme='default' return='void' arguments=''>
-		[02 TextBanner.lua] This function defines how the TextBanner is laid out.
+		[02 TextBanner.lua] Defines how the <Link class='TextBanner' /> is laid out.
+	</Function>
+	<Function name='thified_curstage_index' theme='default' return='string' arguments='bool OnEval'>
+		[04 Other.lua]
 	</Function>
 	<Function name='tobool' theme='_fallback' return='bool' arguments='various v'>
 		[02 Utilities.lua] Converts a string or number to a bool.
 	</Function>
 	<Function name='tonumber' return='float' arguments='various e, int base'>
-		Tries to convert <code>e</code> to a number. Returns <code>nil</code> if
-		it can't convert the input to a number. (<code>base</code> is optional.)
+		Tries to convert <code>e</code> to a number. Returns <code>nil</code> if it can't convert the input to a number. (<code>base</code> is optional.) <br />
+		<code>tonumber</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='tostring' return='string' arguments='various e'>
-		Converts <code>e</code> to a string.
+		Converts <code>e</code> to a string.<br />
+		<code>tostring</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='ToEnumShortString' theme='_fallback' return='string' arguments='enum e'>
-		[02 Enum.lua] Returns a string representing an enum starting from '_'. For example, passing <Link class='ENUM' function='PlayerNumber'>PlayerNumber_P1</Link> to this function will return <code>P1</code>.
+		[02 Enum.lua] Returns a string representing an enum starting from '_'. For example, passing <Link class='ENUM' function='PlayerNumber'>PlayerNumber_P1</Link> to this function will return "P1".
 	</Function>
 	<Function name='Trace' theme='_fallback' return='void' arguments='string sString'>
 		[00 init.lua] Alias for <Link class='lua' function='Trace' />.
 	</Function>
 	<Function name='type' return='string' arguments='various v'>
-		Returns the type of the object as a string. See the Lua manual for valid return values.
+		Returns the type of the object as a string.  There are eight basic types in Lua:
+		<em>nil</em>, <em>boolean</em>, <em>number</em>, <em>string</em>, <em>function</em>, <em>userdata</em>, <em>thread</em>, and <em>table</em>. <br />
+		See the Lua manual for more details.
+	</Function>
+	<Function name='UnlockRewardTypeToLocalizedString' return='string' arguments='UnlockRewardType i'>
+		Returns <Link class='ENUM' function='UnlockRewardType' /> <code>i</code> localized for the current language using strings defined under <code>[UnlockRewardType]</code>.
 	</Function>
 	<Function name='unpack' return='various' arguments='table list, int i, int j'>
-		"Returns the elements from the given table.
-		This function is equivalent to <code>return list[i], list[i+1], ···, list[j]</code>"
-		(<code>i</code> and <code>j</code> are optional; "by default, i is 1 and j is the length of the list.")
+		Returns the elements from table <code>list</code>.	This function is equivalent to <code>return list[i], list[i+1], ···, list[j]</code>.<br />
+		<code>i</code> and <code>j</code> are optional; by default, <code>i</code> is <code>1</code> and <code>j</code> is the length of the list.<br />
+		<code>unpack</code> is a core function of Lua's basic library; see the Lua manual for more details.
 	</Function>
 	<Function name='URLEncode' return='string' arguments='string sInput'>
 		Returns a string with characters escaped for URLs. (e.g. a space becomes '%20')
 	</Function>
 	<Function name='update_centering' return='' arguments=''>
-		This tells Stepmania to update the screen position for any changes to these preferences: CenterImageAddWidth, CenterImageAddHeight, CenterImageTranslateX, CenterImageTranslateY.<br />
+		This tells StepMania to update the screen position for any changes to these preferences: CenterImageAddWidth, CenterImageAddHeight, CenterImageTranslateX, CenterImageTranslateY.<br />
 		This way, a theme can implement a custom interactive screen for adjusting those preferences.
 	</Function>
 	<Function name='Var' theme='_fallback' return='ThreadVariable' arguments=''>
 		[01 base.lua] Alias for <Link class="lua" function="GetThreadVariable">lua.GetThreadVariable</Link>.
 	</Function>
 	<Function name='VersionDate' return='string' arguments=''>
-		Returns the current version's build date.
+		Returns the current version's build date, formatted as YYYYMMDD.
 	</Function>
 	<Function name='VersionTime' return='string' arguments=''>
-		Returns the current version's build time.
+		Returns the current version's build time, formatted as HH:MM:SS.
 	</Function>
 	<Function name='Warn' theme='_fallback' return='void' arguments='string sString'>
 		[00 init.lua] Alias for <Link class='lua' function='Warn' />.
 	</Function>
+	<Function name='Weekday' return='int' arguments=''>
+		Returns the current weekday in the range of <code>0</code>-<code>6</code>, where Sunday is <code>0</code>.
+	</Function>
 	<Function name='WideScale' theme='_fallback' return='float' arguments='float ar43, float ar169'>
 		[04 WidescreenHelpers.lua] Depending on the screen width, scales between <code>ar43</code> (4:3; 640px) and <code>ar169</code> (16:9; 854px).
 	</Function>
 	<Function name='wrap' theme='_fallback' return='float' arguments='float val, float n'>
 		[02 Utilities.lua]
 	</Function>
+	<Function name='width_limit_text' theme='_fallback' return='' arguments='BitmapText text, float limit, float natural_zoom'>
+		[02 Utilities.lua]
+	</Function>
+	<Function name='width_clip_text' theme='_fallback' return='' arguments='BitmapText text, float limit'>
+		[02 Utilities.lua]
+	</Function>
+	<Function name='width_clip_limit_text' theme='_fallback' return='' arguments='BitmapText text, float limit, float natural_zoom'>
+		[02 Utilities.lua]
+	</Function>
 	<Function name='WrapInActorFrame' theme='_fallback' return='ActorFrame' arguments='table children'>
 		[02 ActorDef.lua] Wraps the children in an ActorFrame.
 	</Function>
@@ -667,25 +785,6 @@ save yourself some time, copy this for undocumented things:
 	<Function name='Year' return='int' arguments=''>
 		Returns the current year.
 	</Function>
-
-	<Function name='UserPrefAutoSetStyle' theme='default' return='LuaOptionRow' arguments=''>
-		[03 ThemePrefs.lua] Returns a Lua option row for toggling AutoSetStyle.
-	</Function>
-	<Function name='UserPrefGameplayShowScore' theme='default' return='LuaOptionRow' arguments=''>
-		[03 ThemePrefs.lua] Returns a Lua option row for displaying the score on ScreenGameplay.
-	</Function>
-	<Function name='UserPrefGameplayShowStepsDisplay' theme='default' return='LuaOptionRow' arguments=''>
-		[03 ThemePrefs.lua] Returns a Lua option row for displaying the StepsDisplay on ScreenGameplay.
-	</Function>
-	<Function name='UserPrefGameplayLongFail' theme='default' return='LuaOptionRow' arguments=''>
-		[03 ThemePrefs.lua] Returns a Lua option row for determining the fail length.
-	</Function>
-	<Function name='UserPrefNotePosition' theme='default' return='LuaOptionRow' arguments=''>
-		[03 ThemePrefs.lua] Returns a Lua option row for determining the receptor arrow position.
-	</Function>
-	<Function name='UserPrefShowLotsaOptions' theme='default' return='LuaOptionRow' arguments=''>
-		[03 ThemePrefs.lua] Returns a Lua option row determining how deep the player options menu should go.
-	</Function>
 </GlobalFunctions>
 
 <!-- Namespaces -->

From d62797973fce4a7cf1142593e5ba4034fc9459d4 Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Thu, 25 Jun 2020 04:49:09 -0400
Subject: [PATCH 58/65] update LuaDocs for Singletons, Enums for 5.1-new

---
 Docs/Luadoc/Lua.xml              | 12 +++++
 Docs/Luadoc/LuaDocumentation.xml | 93 ++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)

diff --git a/Docs/Luadoc/Lua.xml b/Docs/Luadoc/Lua.xml
index cbcd85d52b..ff7beb128f 100644
--- a/Docs/Luadoc/Lua.xml
+++ b/Docs/Luadoc/Lua.xml
@@ -2361,6 +2361,18 @@
 			<EnumValue name='&apos;EditState_RecordPaused&apos;' value='2'/>
 			<EnumValue name='&apos;EditState_Playing&apos;' value='3'/>
 		</Enum>
+		<Enum name='EffectMode'>
+			<EnumValue name='&apos;EffectMode_Normal&apos;' value='0'/>
+			<EnumValue name='&apos;EffectMode_Unpremultiply&apos;' value='1'/>
+			<EnumValue name='&apos;EffectMode_ColorBurn&apos;' value='2'/>
+			<EnumValue name='&apos;EffectMode_ColorDodge&apos;' value='3'/>
+			<EnumValue name='&apos;EffectMode_VividLight&apos;' value='4'/>
+			<EnumValue name='&apos;EffectMode_HardMix&apos;' value='5'/>
+			<EnumValue name='&apos;EffectMode_Overlay&apos;' value='6'/>
+			<EnumValue name='&apos;EffectMode_Screen&apos;' value='7'/>
+			<EnumValue name='&apos;EffectMode_YUYV422&apos;' value='8'/>
+			<EnumValue name='&apos;EffectMode_DistanceField&apos;' value='9'/>
+		</Enum>
 		<Enum name='FailType'>
 			<EnumValue name='&apos;FailType_Immediate&apos;' value='0'/>
 			<EnumValue name='&apos;FailType_ImmediateContinue&apos;' value='1'/>
diff --git a/Docs/Luadoc/LuaDocumentation.xml b/Docs/Luadoc/LuaDocumentation.xml
index d063c59940..1f668554e9 100644
--- a/Docs/Luadoc/LuaDocumentation.xml
+++ b/Docs/Luadoc/LuaDocumentation.xml
@@ -1978,6 +1978,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='AnnouncerManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>ANNOUNCER</code>.
+	</Description>
 	<Function name='DoesAnnouncerExist' return='bool' arguments='string sAnnonucer'>
 		Returns true if Announcer <code>sAnnouncer</code> exists.
 	</Function>
@@ -1992,6 +1995,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='ArchHooks'>
+	<Description>
+		This singleton is accessible to Lua via <code>HOOKS</code>.
+	</Description>
 	<Function name='AppHasFocus' return='bool' arguments=''>
 		Returns <code>true</code> if the application presently has focus.
 	</Function>
@@ -2183,6 +2189,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='CharacterManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>CHARMAN</code>.
+	</Description>
 	<Function name='GetAllCharacters' return='{Character}' arguments=''>
 		Returns a table of all characters installed.
 	</Function>
@@ -2331,6 +2340,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='CryptManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>CRYPTMAN</code>.
+	</Description>
 	<Function name='GenerateRandomUUID' return='string' arguments=''>
 		Generates a random UUID (version 4).
 	</Function>
@@ -2633,6 +2645,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='GameManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>GAMEMAN</code>.
+	</Description>
 	<Function name='GetFirstStepsTypeForGame' return='StepsType' arguments='Game game'>
 		Return the first <Link class='StepsType' /> for the specified <code>game</code>.
 	</Function>
@@ -2656,6 +2671,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='GameSoundManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>SOUND</code>.
+	</Description>
 	<Function name='DimMusic' return='void' arguments='float fVolume, float fDuration'>
 		Set the music volume to <code>fVolume</code> for <code>fDuration</code> seconds.
 	</Function>
@@ -2686,6 +2704,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='GameState'>
+	<Description>
+		This singleton is accessible to Lua via <code>GAMESTATE</code>.
+	</Description>
 	<Function name='AddStageToPlayer' return='void' arguments='PlayerNumber pn'>
 		Adds another stage to the specifed player.
 	</Function>
@@ -3195,6 +3216,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='InputFilter'>
+	<Description>
+		This singleton is accessible to Lua via <code>INPUTFILTER</code>.
+	</Description>
 	<Function name='GetMouseWheel' return='float' arguments=''>
 		Returns the mouse wheel value.
 	</Function>
@@ -3231,6 +3255,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='MemoryCardManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>MEMCARDMAN</code>.
+	</Description>
 	<Function name='GetCardLocked' return='bool' arguments='PlayerNumber pn'>
 		Returns <code>true</code> if player <code>pn</code>'s card is locked.
 	</Function>
@@ -3275,6 +3302,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='MessageManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>MESSAGEMAN</code>.
+	</Description>
 	<Function name='Broadcast' return='void' arguments='string sMessage, table paramTable'>
 		Broadcast the message to all listeners subscribed to <code>sMessage</code>. The
 		second argument is an optional table of parameters. It may be omitted or explicitly
@@ -3339,6 +3369,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='NoteSkinManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>NOTESKIN</code>.
+	</Description>
 	<Function name='GetMetric' return='string' arguments='string sElement, string sValue'>
 		Returns a string from the specified element and value.
 	</Function>
@@ -4117,6 +4150,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='PrefsManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>PREFSMAN</code>.
+	</Description>
 	<Function name='GetPreference' return='various' arguments='string sPreference'>
 		Return the value of the preference <code>sPreference</code>.
 	</Function>
@@ -4339,6 +4375,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='ProfileManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>PROFILEMAN</code>.
+	</Description>
 	<Function name='GetLocalProfile' return='Profile' arguments='string sProfileID'>
 		Returns the Profile for the specified profile ID.
 	</Function>
@@ -4438,6 +4477,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='RageDisplay'>
+	<Description>
+		This singleton is accessible to Lua via <code>DISPLAY</code>.
+	</Description>
 	<Function name='GetDisplayHeight' return='int' arguments=''>
 		Return the height of the display.
 	</Function>
@@ -4517,6 +4559,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='RageFileManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>FILEMAN</code>.
+	</Description>
 	<Function name='DoesFileExist' return='bool' arguments='string sPath'>
 		Returns <code>true</code> if a file exists at <code>sPath</code>.
 	</Function>
@@ -4531,6 +4576,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='RageInput'>
+	<Description>
+		This singleton is accessible to Lua via <code>INPUTMAN</code>.
+	</Description>
 	<Function name='GetDescriptions' return='{string}' arguments=''>
 		Return an array of connected input device descriptions.
 	</Function>
@@ -4759,6 +4807,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='ScreenManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>SCREENMAN</code>.
+	</Description>
 	<Function name='AddNewScreenToTop' return='void' arguments='string sScreenName, string sMessage'>
 		Adds a screen at the top of the screen stack. (<code>sMessage</code> is an optional ScreenMessage posted once the new screen is finished.)
 	</Function>
@@ -5140,6 +5191,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='SongManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>SONGMAN</code>.
+	</Description>
 	<Function name='DoesCourseGroupExist' return='bool' arguments='string sGroup'>
 		Returns <code>true</code> if the specified course group exists.
 	</Function>
@@ -5469,6 +5523,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='StatsManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>STATSMAN</code>.
+	</Description>
 	<Function name='GetAccumPlayedStageStats' return='StageStats' arguments=''>
 		Returns the accumulated played StageStats.
 	</Function>
@@ -5699,6 +5756,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='ThemeManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>THEME</code>.
+	</Description>
 	<Function name='DoesLanguageExist' return='bool' arguments='string langName'>
 		Returns <code>true</code> if the specified language exists in the current theme.
 	</Function>
@@ -5988,6 +6048,9 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='UnlockManager'>
+	<Description>
+		This singleton is accessible to Lua via <code>UNLOCKMAN</code>.
+	</Description>
 	<Function name='AnyUnlocksToCelebrate' return='bool' arguments=''>
 		Returns <code>true</code> if there are any unlocks to celebrate.
 	</Function>
@@ -6087,6 +6150,20 @@ save yourself some time, copy this for undocumented things:
 </Classes>
 <!-- Enums -->
 <Enums>
+<Description>
+	StepMania's enums are exposed to Lua as global tables.  Note that although the enum values start at 0, these global Lua tables are indexed starting at 1.<br />
+	Functions that require enums as arguments will accept either the string constant or number value.<br />
+	For example, <Link class='GameState' function='SetPreferredDifficulty' /> accepts a <code>PlayerNumber</code> and <code>Difficulty</code> as arguments.
+	Each of these is valid way to set P1's preferred difficulty to hard:<br />
+<pre><code>
+-- using strings
+GAMESTATE:SetPreferredDifficulty( "PlayerNumber_P1", "Difficulty_Hard" )
+-- using values
+GAMESTATE:SetPreferredDifficulty( 0, 3 )
+-- using global Lua tables
+GAMESTATE:SetPreferredDifficulty( PlayerNumber[1], Difficulty[4] )
+</code></pre>
+</Description>
 <Enum name='BlendMode'>
 	<Description>
 		Blending modes. See <Link class='Actor' function='blend' />.
@@ -6103,4 +6180,20 @@ save yourself some time, copy this for undocumented things:
 	</Description>
 </Enum>
 </Enums>
+
+<!-- Singletons -->
+<Singletons>
+<Description>
+	The StepMania engine uses singletons internally when it needs only one instance of a class.<br />
+	Each singleton has a class name (e.g. RageDisplay, NoteSkinManager, etc.) from the C++ engine, and a similar (but different) userdata name available to Lua (e.g. <code>DISPLAY</code>, <code>NOTESKIN</code>, etc.).<br />
+Simple examples:
+<pre><code>
+-- use GameState's singleton to get the current song
+local song = GAMESTATE:GetCurrentSong()
+
+-- use ScreenManager's singleton to briefly show text on-screen
+SCREENMAN:SystemMessage("hello from Lua!")
+</code></pre>
+</Description>
+</Singletons>
 </Documentation>

From 91bf61a178195f87101b6ed4754e6f1f283fe569 Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Thu, 25 Jun 2020 04:55:13 -0400
Subject: [PATCH 59/65] update LuaDocs for Classes

Fix, clarify, and expand prose in LuaDocumentation.xml for classes made
available to Lua.

Add elements for DeviceList, InputList, Quad, and SongMeterDisplay to
Lua.xml.
---
 Docs/Luadoc/Lua.xml              |   8 +
 Docs/Luadoc/LuaDocumentation.xml | 680 ++++++++++++++++++++++++-------
 2 files changed, 538 insertions(+), 150 deletions(-)

diff --git a/Docs/Luadoc/Lua.xml b/Docs/Luadoc/Lua.xml
index ff7beb128f..3da459c121 100644
--- a/Docs/Luadoc/Lua.xml
+++ b/Docs/Luadoc/Lua.xml
@@ -783,6 +783,8 @@
 			<Function name='get_dirty'/>
 			<Function name='destroy'/>
 		</Class>
+		<Class base='BitmapText' name='DeviceList'>
+		</Class>
 		<Class name='DisplayMode'>
 			<Function name='GetWidth'/>
 			<Function name='GetHeight'/>
@@ -1044,6 +1046,8 @@
 			<Function name='GetMouseX'/>
 			<Function name='GetMouseY'/>
 		</Class>
+		<Class base='BitmapText' name='InputList'>
+		</Class>
 		<Class base='ActorFrame' name='LifeMeter'>
 			<Function name='GetLife'/>
 			<Function name='IsFailing'/>
@@ -1534,6 +1538,8 @@
 			<Function name='SaveProfile'/>
 			<Function name='SetStatsPrefix'/>
 		</Class>
+		<Class base='Sprite' name='Quad'>
+		</Class>
 		<Class name='RadarValues'>
 			<Function name='GetValue'/>
 		</Class>
@@ -1870,6 +1876,8 @@
 			<Function name='WasLoadedFromAdditionalCourses'/>
 			<Function name='WasLoadedFromAdditionalSongs'/>
 		</Class>
+		<Class base='MeterDisplay' name='SongMeterDisplay'>
+		</Class>
 		<Class name='SongOptions'>
 			<Function name='AssistClap'/>
 			<Function name='AssistMetronome'/>
diff --git a/Docs/Luadoc/LuaDocumentation.xml b/Docs/Luadoc/LuaDocumentation.xml
index 1f668554e9..8de4ee0a4a 100644
--- a/Docs/Luadoc/LuaDocumentation.xml
+++ b/Docs/Luadoc/LuaDocumentation.xml
@@ -974,6 +974,11 @@ save yourself some time, copy this for undocumented things:
 <!-- Classes -->
 <Classes>
 <Class name='Actor'>
+	<Description>
+		<em>Actor</em> is the base class containing common methods that all specialized actor classes inherit.
+		For example, <Link class='Actor' function='GetX'>GetX</Link> is a method belonging to <em>Actor</em>,
+		but <Link class='Sprite' />s, <Link class='BitmapText' />s, <Link class='Quad' />s, and so on can use <code>GetX()</code>.
+	</Description>
 	<Function name='AddWrapperState' return='ActorFrame' arguments=''>
 		This adds a wrapper state around the Actor, which is like wrapping the Actor in an ActorFrame, except that you can use it on any actor, and add or remove wrapper states in response to things that happen while the screen is being used. (wrapping an Actor in an ActorFrame normally requires setting it up before the screen starts)<br />
 		The ActorFrame that is returned is the wrapper state, for convenience.<br />
@@ -1034,19 +1039,20 @@ save yourself some time, copy this for undocumented things:
 		Sets Texture Filtering for an Actor to <code>b</code>.
 	</Function>
 	<Function name='accelerate' return='void' arguments='float fRate'>
-		Plays the commands that follow at an accelerated rate (<code>fRate</code> * <code>fRate</code>), where <code>fRate</code> is in seconds.
+		Plays the commands that follow at an accelerated rate (fRate²), where <code>fRate</code> is in seconds.<br />
+		<code>accelerate</code> is a basic tween command, along with <Link function='linear' />, <Link function='decelerate' />, <Link function='spring' />, and <Link function='tween' />.
 	</Function>
 	<Function name='addcommand' return='void' arguments='string sName, ActorCommand cmd'>
 		Adds a command to the Actor.
 	</Function>
 	<Function name='addrotationx' return='void' arguments='float rot'>
-		Adds <code>rot</code> to the Actor's current x rotation.
+		Adds <code>rot</code> degrees to the Actor's current X rotation.
 	</Function>
 	<Function name='addrotationy' return='void' arguments='float rot'>
-		Adds <code>rot</code> to the Actor's current y rotation.
+		Adds <code>rot</code> degrees to the Actor's current Y rotation.
 	</Function>
 	<Function name='addrotationz' return='void' arguments='float rot'>
-		Adds <code>rot</code> to the Actor's current z rotation.
+		Adds <code>rot</code> degrees to the Actor's current Z rotation.
 	</Function>
 	<Function name='addx' return='void' arguments='float xPos'>
 		Adds <code>xPos</code> to the Actor's current x position.
@@ -1073,13 +1079,13 @@ save yourself some time, copy this for undocumented things:
 		Sets the Actor's base alpha to <code>fAlpha</code>, where <code>fAlpha</code> is in the range 0..1.
 	</Function>
 	<Function name='baserotationx' return='void' arguments='float rot'>
-		Sets the Actor's base X rotation to <code>rot</code>.
+		Sets the Actor's base X rotation to <code>rot</code> degrees.
 	</Function>
 	<Function name='baserotationy' return='void' arguments='float rot'>
-		Sets the Actor's base Y rotation to <code>rot</code>.
+		Sets the Actor's base Y rotation to <code>rot</code> degrees.
 	</Function>
 	<Function name='baserotationz' return='void' arguments='float rot'>
-		Sets the Actor's base Z rotation to <code>rot</code>.
+		Sets the Actor's base Z rotation to <code>rot</code> degrees.
 	</Function>
 	<Function name='basezoom' return='void' arguments='float zoom'>
 		Sets the Actor's base zoom to <code>zoom</code>.
@@ -1109,13 +1115,16 @@ save yourself some time, copy this for undocumented things:
 		[02 Actor.lua]
 	</Function>
 	<Function name='Center' theme='_fallback' return='void' arguments=''>
-		[02 Actor.lua] Centers an Actor on the screen. (equivalent to <code>x,SCREEN_CENTER_X;y,SCREEN_CENTER_Y</code>)
+		[02 Actor.lua] Centers an Actor on the screen.<br />
+		<code>self:Center()</code> is equivalent to <code>self:x(SCREEN_CENTER_X):y(SCREEN_CENTER_Y)</code>
 	</Function>
 	<Function name='CenterX' theme='_fallback' return='void' arguments=''>
-		[02 Actor.lua] Centers an Actor on the X axis. (equivalent to <code>x,SCREEN_CENTER_X</code>)
+		[02 Actor.lua] Centers an Actor on the X axis.<br />
+		<code>self:CenterX()</code> is equivalent to <code>self:x(SCREEN_CENTER_X)</code>
 	</Function>
 	<Function name='CenterY' theme='_fallback' return='void' arguments=''>
-		[02 Actor.lua] Centers an Actor on the y axis. (equivalent to <code>y,SCREEN_CENTER_Y</code>)
+		[02 Actor.lua] Centers an Actor on the y axis.<br />
+		<code>self:CenterY()</code> is equivalent to <code>self:y(SCREEN_CENTER_Y)</code>
 	</Function>
 	<Function name='clearzbuffer' return='void' arguments='bool bClear'>
 		Determines if the z-buffer should be cleared or not.
@@ -1138,10 +1147,11 @@ save yourself some time, copy this for undocumented things:
 		Crops <code>percent</code> of the Actor from the top, where <code>percent</code> is in the range 0..1.
 	</Function>
 	<Function name='cullmode' return='void' arguments='CullMode mode'>
-		Sets the Actor's cull mode to <code>mode</code>.
+		Sets the Actor's <Link class='ENUM' function='CullMode' /> to <code>mode</code>.
 	</Function>
 	<Function name='decelerate' return='void' arguments='float fRate'>
-		Plays the commands that follow at an decelerated rate (1 - (1-<code>fRate</code>) * (1-<code>fRate</code>)), where <code>fRate</code> is in seconds.
+		Plays the commands that follow at an decelerated rate (<code>1 - (1-fRate) * (1-fRate)</code>), where <code>fRate</code> is in seconds.<br />
+		<code>decelerate</code> is a basic tween command, along with <Link function='linear' />, <Link function='accelerate' />, <Link function='spring' />, and <Link function='tween' />.
 	</Function>
 	<Function name='diffuse' return='void' arguments='color c'>
 		Set the Actor's diffuse color to <code>c</code>.
@@ -1150,7 +1160,9 @@ save yourself some time, copy this for undocumented things:
 		Sets the Actor's alpha level to <code>fAlpha</code>, where <code>fAlpha</code> is in the range 0..1.
 	</Function>
 	<Function name='diffuseblink' return='void' arguments=''>
-		Makes the Actor switch between two colors immediately.  See Themerdocs/effect_colors.txt for an example.
+		Makes the Actor switch between two colors immediately.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/effect_colors.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/effect_colors.txt</a>
+		for an example.
 	</Function>
 	<Function name='diffusebottomedge' return='void' arguments=''>
 		Sets the Actor's bottom edge color to <code>c</code>.
@@ -1168,13 +1180,17 @@ save yourself some time, copy this for undocumented things:
 		Sets the Actor's lower right corner color to <code>c</code>.
 	</Function>
 	<Function name='diffuseramp' return='void' arguments=''>
-		Makes the Actor switch between two colors, jumping back to the first after reaching the second.  See Themerdocs/effect_colors.txt for an example.
+		Makes the Actor switch between two colors, jumping back to the first after reaching the second.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/effect_colors.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/effect_colors.txt</a>
+		for an example.
 	</Function>
 	<Function name='diffuserightedge' return='void' arguments='color c'>
 		Sets the Actor's right edge color to <code>c</code>.
 	</Function>
 	<Function name='diffuseshift' return='void' arguments=''>
-		Makes the Actor shift between two colors smoothly.  See Themerdocs/effect_colors.txt for an example.
+		Makes the Actor shift between two colors smoothly.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/effect_colors.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/effect_colors.txt</a>
+		for an example.
 	</Function>
 	<Function name='diffusetopedge' return='void' arguments='color c'>
 		Sets the Actor's top edge color to <code>c</code>.
@@ -1277,8 +1293,8 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetEffectDelta' return='float' arguments=''>
 		Returns the Actor's current effect delta.
 	</Function>
-	<Function name='geteffectmagnitude' return='float' arguments=''>
-		Returns the Actor's current effect magnitude as three floats (not one; I hate Lua.xsd).
+	<Function name='geteffectmagnitude' return='float, float, float' arguments=''>
+		Returns the Actor's current effect magnitude as three floats.
 	</Function>
 	<Function name='GetGlow' return='color' arguments=''>
 		Returns the Actor's current glow color.
@@ -1295,15 +1311,17 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetHeight' return='float' arguments=''>
 		Returns the Actor's current height.
 	</Function>
-	<!-- todo: GetRotation() returns three numbers, the x, y, and z -->
+	<Function name='getrotation' return='float, float, float' arguments=''>
+		Returns the Actor's current X, Y, and Z rotation in degrees as three separate floats.
+	</Function>
 	<Function name='GetRotationX' return='float' arguments=''>
-		Returns the Actor's current X rotation.
+		Returns the Actor's current X rotation in degrees.
 	</Function>
 	<Function name='GetRotationY' return='float' arguments=''>
-		Returns the Actor's current Y rotation.
+		Returns the Actor's current Y rotation in degrees.
 	</Function>
 	<Function name='GetRotationZ' return='float' arguments=''>
-		Returns the Actor's current Z rotation.
+		Returns the Actor's current Z rotation in degrees.
 	</Function>
 	<Function name='GetSecsIntoEffect' return='float' arguments=''>
 		Returns the number of seconds into the currently running effect (e.g. diffuseshift, bob).
@@ -1330,13 +1348,19 @@ save yourself some time, copy this for undocumented things:
 		Sets the Actor's glow color.
 	</Function>
 	<Function name='glowblink' return='void' arguments=''>
-		Makes the Actor glow between two colors immediately.  See Themerdocs/effect_colors.txt for an example.
+		Makes the Actor glow between two colors immediately.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/effect_colors.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/effect_colors.txt</a>
+		for an example.
 	</Function>
 	<Function name='glowramp' return='void' arguments=''>
-		Makes the Actor glow between two colors smoothly, jumping back to the first at the end.  See Themerdocs/effect_colors.txt for an example.
+		Makes the Actor glow between two colors smoothly, jumping back to the first at the end.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/effect_colors.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/effect_colors.txt</a>
+		for an example.
 	</Function>
 	<Function name='glowshift' return='void' arguments=''>
-		Makes the Actor glow between two colors smoothly.  See Themerdocs/effect_colors.txt for an example.
+		Makes the Actor glow between two colors smoothly.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/effect_colors.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/effect_colors.txt</a>
+		for an example.
 	</Function>
 	<Function name='halign' return='void' arguments='float fAlign'>
 		Set the fractional horizontal alignment of the Actor according to <code>fAlign</code> which should be a float in the range 0..1. An alignment of 0 is left aligned while an alignment of 1 is right aligned. See <Link function='horizalign' /> for the common case.
@@ -1360,7 +1384,8 @@ save yourself some time, copy this for undocumented things:
 		Hurries up an Actor's tweening by <code>factor</code>.
 	</Function>
 	<Function name='linear' return='void' arguments='float fRate'>
-		Plays the commands that follow at a normal rate, where <code>fRate</code> is in seconds.
+		Plays the commands that follow at a normal (linear) rate, where <code>fRate</code> is in seconds.<br />
+		<code>linear</code> is a basic tween command, along with <Link function='accelerate' />, <Link function='decelerate' />, <Link function='spring' />, and <Link function='tween' />.
 	</Function>
 	<Function name='LyricCommand' theme='_fallback' return='void' arguments='string side'>
 		[02 Lyrics.lua] Plays the lyric command for the specified <code>side</code> (<code>"Back"</code> or <code>"Front"</code>).
@@ -1399,13 +1424,13 @@ save yourself some time, copy this for undocumented things:
 		Sets the roll of this Actor to <code>fRoll</code>.
 	</Function>
 	<Function name='rotationx' return='void' arguments='float fRotation'>
-		Set the Actor's rotation on the X axis to <code>fAlign</code>.
+		Set the Actor's rotation on the X axis to <code>fRotation</code> degrees.
 	</Function>
 	<Function name='rotationy' return='void' arguments='float fRotation'>
-		Set the Actor's rotation on the Y axis to <code>fAlign</code>.
+		Set the Actor's rotation on the Y axis to <code>fRotation</code> degrees.
 	</Function>
 	<Function name='rotationz' return='void' arguments='float fRotation'>
-		Set the Actor's rotation on the Z axis to <code>fAlign</code>.
+		Set the Actor's rotation on the Z axis to <code>fRotation</code> degrees.
 	</Function>
 	<!-- RunCommandsRecursively -->
 	<Function name='scale_or_crop_alternative' theme="_fallback" return='void' arguments=''>
@@ -1465,7 +1490,9 @@ save yourself some time, copy this for undocumented things:
 	<Function name='spin' return='void' arguments=''>
 		Tells the Actor to spin. Can use <Link function='effectmagnitude' /> to define different spinning behavior.
 	</Function>
-	<!-- spring -->
+	<Function name='spring' return='' arguments=''>
+		<code>spring</code> is a basic tween command, along with <Link function='linear' />, <Link function='accelerate' />, <Link function='decelerate' />, and <Link function='tween' />.
+	</Function>
 	<Function name='stopeffect' return='void' arguments=''>
 		Stops any effect the Actor has.
 	</Function>
@@ -1482,8 +1509,11 @@ save yourself some time, copy this for undocumented things:
 		Determines if the Actor should use texture wrapping or not.
 	</Function>
 	<Function name='tween' return= '' arguments='float time, TweenType type, table params'>
-		Uses type to determine the tween to use.  The type must be one of the TweenType enum values.  If the type is note TweenType_Bezier, the params table is ignored.  If the type is TweenType_Bezier, then the params table must have 4 or 8 numbers.  4 numbers in the params creates a 1 dimensional bezier curve, 8 numbers creates a 2 dimensional bezier curve.<br />
-		It's usually more convenient to use Actor:linear, Actor:accelerate, and so on, rather than using Actor:tween directly.
+		Generic method for tweening an actor.<br />
+		<code>time</code> is in seconds.  <code>type</code> is a <Link class='ENUM' function='TweenType' /><br />
+		If the type is <code>TweenType_Bezier</code>, then the <code>params</code> table must have 4 or 8 numbers.  4 numbers creates a 1 dimensional bezier curve, 8 numbers creates a 2 dimensional bezier curve.<br />
+		If the type is not <code>TweenType_Bezier</code>, the <code>params</code> table is ignored.<br />
+		It's usually more convenient to use <Link function='linear' />, <Link function='accelerate' />, <Link function='decelerate' />, or <Link function='spring' /> rather than using Actor:tween() directly.
 	</Function>
 	<Function name='valign' return='void' arguments='float fAlign'>
 		Set the fractional vertical alignment of the Actor according to <code>fAlign</code> which should be a float in the range 0..1. An alignment of 0 is top aligned while an alignment of 1 is bottom aligned. See <Link function="vertalign" /> for the common case.
@@ -1575,6 +1605,66 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='ActorFrame'>
+	<Description>
+		ActorFrames are containers that allow multiple children actors to be grouped and scripted together.<br />
+		In theming, the StepMania engine expects a screen layer (underlay, overlay, decorations, in, out, cancel)
+		file to return one actor, and it is common to return one ActorFrame that contains many actors of various
+		specialization.<br />
+		A common convention is to add children at the next index (current size of the table plus <code>1</code>).<br />
+		Basic example:
+<pre><code>
+-- in the context of a lua file as a screen layer
+-- this ActorFrame is a table
+local af = Def.ActorFrame{}
+
+-- add a Sprite at the next index
+af[#af+1] = Def.Sprite{
+	Texture="smilingsun.png"
+}
+
+-- add a BitmapText at the next index
+af[#af+1] = Def.BitmapText{
+	Font="Common normal",
+	Text="Yo!"
+}
+
+-- have the file return the ActorFrame
+-- for the StepMania engine to interpret
+return af
+</code></pre>
+	When actor commands like <Link class='Actor' function='xy' /> and <Link class='Actor' function='zoom' />
+	are used position and scale an ActorFrame, its children will position relative to the parent ActorFrame
+	and scale proportionally.<br />
+	For example, if you want to animate 50 actors moving 100px to the right in unison, it is easier to move the
+	parent ActorFrame than each actor individually.<br />
+	Basic example:
+<pre><code>
+local af = Def.ActorFrame{}
+
+-- move the ActorFrame +100px
+-- over a 2 second duration
+-- its children will move with it
+af.OnCommand=function(self)
+	self:linear(2):addx(100)
+end
+
+-- add various children actors
+-- to the parent ActorFrame
+af[#af+1] = Def.Sprite{
+	Texture="taro.png"
+}
+
+af[#af+1] = Def.Sprite{
+	Texture="laer.png"
+}
+
+-- etc.
+
+return af
+</code></pre>
+	ActorFrames can contain ActorFrames, and doing so is good design for sufficiently complex screens.
+	</Description>
+
 	<Function name='AddChildFromPath' return='bool' arguments='string sPath'>
 		Adds a child to the ActorFrame from the specified path.
 	</Function>
@@ -1582,14 +1672,14 @@ save yourself some time, copy this for undocumented things:
 		Sets the field of view for the ActorFrame.
 	</Function>
 	<Function name='GetChild' return='Actor' arguments='string sName'>
-		Returns the child with a name of <code>sName</code>.<br/>
-		If there are multiple children with that name, returns an array of those children.<br/>
+		Returns the child with a name of <code>sName</code>.<br />
+		If there are multiple children with that name, returns an array of those children.<br />
 		The table also acts as a pass through layer, function calls pass through to the last child of that name.
 	</Function>
 	<Function name='GetChildren' return='{Actor}' arguments=''>
-		Returns a table of all the children in the ActorFrame.<br/>
-		The table is indexed by the names of the children.<br/>
-		If there are multiple children with the same name, the entry for that name is an array of those children.<br/>
+		Returns a table of all the children in the ActorFrame.<br />
+		The table is indexed by the names of the children.<br />
+		If there are multiple children with the same name, the entry for that name is an array of those children.<br />
 		The table also acts as a pass through layer, function calls pass through to the last child of that name.
 	</Function>
 	<Function name='GetDrawFunction' return='LuaReference' arguments=''>
@@ -1800,17 +1890,19 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 	<Function name='SetDrawState' return='void' arguments='table { Mode= mode, First= first, Num= num }'>
 		Sets the draw state variables to the values in the table.<br />
-		Mode must be a <Link class='ENUM' function='DrawMode'>DrawMode</Link>.<br />
-		First is the index of the first vertex to draw.<br />
-		Num is the number of vertices to draw.  -1 for Num means draw all verts after First.<br />
+		<code>Mode</code> must be a <Link class='ENUM' function='DrawMode'/>.<br />
+		<code>First</code> is the index of the first vertex to draw.<br />
+		<code>Num</code> is the number of vertices to draw.  -1 for <code>Num</code> means draw all verts after <code>First</code>.<br />
 		Any value not in the table defaults to the already set value.<br />
-		Examples:<br />
-		-- Sets all three parts of the draw state.<br />
-		self:SetDrawState{Mode="DrawMode_Quads", First= 1, Num= -1}<br />
-		-- Set only the draw mode.  First and Num remain unchanged from previous.<br />
-		self:SetDrawState{Mode="DrawMode_Quads"}<br />
-		-- Set the first and number to draw.  Draw mode remains unchanged.<br />
-		self:SetDrawState{First= 3, Num= 4}<br />
+		Examples:
+<pre><code>
+-- Sets all three parts of the draw state.
+self:SetDrawState{Mode="DrawMode_Quads", First= 1, Num= -1}
+-- Set only the draw mode.  First and Num remain unchanged from previous.
+self:SetDrawState{Mode="DrawMode_Quads"}
+-- Set the first and number to draw.  Draw mode remains unchanged.
+self:SetDrawState{First= 3, Num= 4}
+</code></pre>
 	</Function>
 	<Function name='GetDestDrawMode' return='DrawMode' arguments='void'>
 		Get the <Link class='ENUM' function='DrawMode'>DrawMode</Link> of the destination tween state.
@@ -1946,11 +2038,30 @@ save yourself some time, copy this for undocumented things:
 </Class>
 <Class name='ActorSound'>
 	<Description>
-		This Actor represents a playable sound.  Though the C++ class is ActorSound, it is accessible to Lua via <code>Def.Sound</code>.<br/>
-		There are three attributes that can be set as booleans on load:<br />
+		This actor represents a playable sound.  Though the C++ class is ActorSound, it is accessible to Lua via <code>Def.Sound</code>.<br />
+		You must provide <em>ActorSound</em>s with a filepath to the asset using their <code>File</code> attribute.
+<pre><code>
+Def.Sound{
+	File="./path/to/soundeffect.ogg",
+	OnCommand=function(self)
+		-- play this sound effect at the parent screen's OnCommand
+		self:play()
+	end
+}
+</code></pre>
+		 <em>ActorSound</em>s have three additional boolean attributes:<br />
 		• <code>SupportPan</code> - Let the sound pan from side to side.<br />
 		• <code>SupportRateChanging</code> - Let the sound change rate and pitch.<br />
-		• <code>IsAction</code> - If true, the sound is an action sound, and will be muted if the MuteActions preference is turned on.
+		• <code>IsAction</code> - If true, the sound is an action sound, and will be muted if the MuteActions preference is turned on.<br />
+		Basic example:
+<pre><code>
+Def.Sound{
+	File="./path/to/soundeffect.ogg",
+	SupportPan=true,
+	SupportRateChanging=true,
+	IsAction=false,
+}
+</code></pre>
 	</Description>
 	<Function name='get' return='RageSound' arguments=''>
 		Returns the <Link class='RageSound' /> that can be played by this Actor.
@@ -2012,10 +2123,10 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetPercentScrolling' return='float' arguments=''>
 		<!-- todo -->
 	</Function>
-	<Function name='LoadBackgroundFromUnlockEntry' return='void' arguments='UnlockEntry pUE'>
+	<Function name='LoadBackgroundFromUnlockEntry' return='void' arguments='UnlockEntry ue'>
 		Loads the background from an UnlockEntry.
 	</Function>
-	<Function name='LoadBannerFromUnlockEntry' return='void' arguments='UnlockEntry pUE'>
+	<Function name='LoadBannerFromUnlockEntry' return='void' arguments='UnlockEntry ue'>
 		Loads the banner from an UnlockEntry.
 	</Function>
 	<Function name='LoadCardFromCharacter' return='void' arguments='Character pCharacter'>
@@ -2050,6 +2161,40 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='BitmapText'>
+	<Description>
+		<em>BitmapText</em> actors are used to display text on-screen.<br />
+		The font can be specified using the <code>Font</code> attribute. It takes a font name a string,
+		pathed relative to the current theme's <code>./Fonts/</code> directory.<br />
+		StepMania expects fonts to be formatted as spritesheets with accompanying ini files.
+		These can be generated from ttf files using <em>Texture Font Generator.exe</em> in the
+		<code>./Program/</code> directory of packaged StepMania releases.<br />
+		The text displayed can be initially set using the <code>Text</code> attribute, and changed
+		later using <Link class='BitmapText' function='settext'>settext()</Link>.<br />
+		Basic usage example:
+<pre><code>
+Def.BitmapText{
+	Font="Common normal",
+	Text="Hello!",
+	OnCommand=function(self)
+		self:sleep(2):settext("Hey!")
+	end
+}
+</code></pre>
+<br />
+	The font can alternatively be specified with the <code>File</code> attribute,
+	which takes the path to the ini file as a string, relative to the root of StepMania.<br />
+	Basic example:
+<pre><code>
+-- use a custom font from a simfile
+local song_dir = GAMESTATE:GetCurrentSong():GetSongDir()
+local ini_path = "Fonts/courier/_courier 20px.ini"
+
+Def.BitmapText{
+	File=song_dir .. ini_path,
+	Text="Hello, World!"
+}
+</code></pre>
+	</Description>
 	<Function name='AddAttribute' return='void' arguments='int iPos, Attribute attr'>
 		Add the attribute <code>attr</code> to the string at position
 		<code>iPos</code>.<br />
@@ -2445,6 +2590,12 @@ save yourself some time, copy this for undocumented things:
 		Destroys the spline, freeing the memory allocated for it.  This can only be called on splines created with create_spline().
 	</Function>
 </Class>
+<Class name='DeviceList'>
+	<Description>
+		A newline-delimited list of available input devices.<br />
+		The list shown will the same as that returned by <Link class='RageInput' function='GetDescriptions'>INPUTMAN:GetDescriptions()</Link>, but with "MonkeyKeyboard" removed.
+	</Description>
+</Class>
 <Class name='DifficultyIcon'>
 	<Function name='SetFromDifficulty' return='void' arguments='Difficulty dc'>
 		Sets the DifficultyIcon's state from the difficulty passed in.
@@ -2657,7 +2808,7 @@ save yourself some time, copy this for undocumented things:
 	<Function name='StepsTypeToLocalizedString' return='string' arguments='StepsType st'>
 		Return the localized string representation of <code>st</code>.
 	</Function>
-	<Function name='GetEnabledGames' return='{string}'>
+	<Function name='GetEnabledGames' return='{string}' arguments=''>
 		Returns a table of all selectable games.
 	</Function>
 	<Function name='GetStylesForGame' return='{style}' arguments='string game'>
@@ -2726,15 +2877,17 @@ save yourself some time, copy this for undocumented things:
 		The second argument is optional. Apply the GameCommand represented by <code>sCommand</code>
 		for <code>pn</code>, if given. See <Link class='GameCommand' />.
 	</Function>
-	<Function name='CanSafelyEnterGameplay' return='bool,string' arguments=''>
-		Checks various things to determine whether the game will crash when gameplay starts.  Returns false and a string if gameplay cannot be entered safely.<br />
+	<Function name='CanSafelyEnterGameplay' return='bool, string' arguments=''>
+		Checks various things to determine whether the game will crash when gameplay starts.  Returns <code>false</code> and an error string if gameplay cannot be entered safely.<br />
 		Might not work in all cases, but will catch things like a player not having
 		steps set or no current song or style.  Mainly exists for people with a custom ScreenSelectMusic replacement.<br />
-		Example:<br />
-		local can, reason= GAMESTATE:CanSafelyEnterGameplay()<br />
-		if not can then<br />
-		lua.ReportScriptError("Cannot safely enter gameplay: " .. tostring(reason))<br />
-		end<br />
+		Example:
+<pre><code>
+local can, reason = GAMESTATE:CanSafelyEnterGameplay()
+if not can then
+	lua.ReportScriptError("Cannot safely enter gameplay: " .. tostring(reason))
+end
+</code></pre>
 	</Function>
 	<Function name='ClearStageModifiersIllegalForCourse' return='void' arguments=''>
 		Removes any stage modifiers that are illegal for course play.
@@ -2754,7 +2907,7 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetCharacter' return='Character' arguments='PlayerNumber pn'>
 		Returns the current <Link class='Character' /> for the specified <Link class='ENUM' function='PlayerNumber' />.
 	</Function>
-	<Function name='GetCoinMode' return='CoinMode'>
+	<Function name='GetCoinMode' return='CoinMode' arguments=''>
 		Returns the current <Link class='ENUM' function='CoinMode' />.
 	</Function>
 	<Function name='GetCoins' return='int' arguments=''>
@@ -3229,6 +3382,11 @@ save yourself some time, copy this for undocumented things:
 		Returns the Y position of the mouse.
 	</Function>
 </Class>
+<Class name='InputList'>
+	<Description>
+		A newline-delimited list of inputs that are currently being pressed.  It will update as inputs are held and released.  Handy for custom TestInput screens.
+	</Description>
+</Class>
 <Class name='LifeMeter'>
 	<Function name='GetLife' return='float' arguments=''>
 		Returns the amount of life left in the LifeMeter as a float in the range 0..1.
@@ -3297,7 +3455,7 @@ save yourself some time, copy this for undocumented things:
 		Sets the MenuTimer's stealth setting to <code>bStealth</code>. If
 		<code>true</code>, the timer will be invisible and silent.
 	</Function>
-	<Function name='stop' return='void'>
+	<Function name='stop' return='void' arguments=''>
 		Stops the MenuTimer by setting it to 0 and pausing.
 	</Function>
 </Class>
@@ -3589,12 +3747,12 @@ save yourself some time, copy this for undocumented things:
 </Class>
 <Class name='PlayerOptions'>
 	<Description>
-		All these functions have an optional last argument:  If the last argument is the boolean value true, then instead of returning the previous settings as normal, they will instead return the PlayerOptions object.<br />
+		All these functions have an optional last argument:  If the last argument is the boolean value <code>true</code>, then instead of returning the previous settings as normal, they will instead return the PlayerOptions object.<br />
 		This allows you to chain them like this:<br />
-		player_options:Twirl(5, 1, true):Roll(5, true):Dizzy(true):Twirl()<br />
+		<code>player_options:Twirl(5, 1, true):Roll(5, true):Dizzy(true):Twirl()</code><br />
 		<br />
-		Special note:  Functions that take a bool as their arg must have true as the second arg to be used with chaining.<br />
-		"player_options:Backwards(true, true):Beat(5)" will chain, "player_options:Backwards(true):Beat(5)" will not chain.<br />
+		Functions that take a bool as their arg must have <code>true</code> as the second arg to be used with chaining.<br />
+		<code>player_options:Backwards(true, true):Beat(5)</code> will chain.  <code>player_options:Backwards(true):Beat(5)</code> will not chain.<br />
 		<br />
 		Most options fall into one of four types:  float, int, bool, or enum.<br />
 		Float type options have this interface:<br />
@@ -3603,15 +3761,25 @@ save yourself some time, copy this for undocumented things:
 		If approach_speed is a float, sets the speed of the transition to approach_speed.  Returns the previous values of both.<br />
 		approach_speed is in units of n per second.  value will be approached at the rate of approach_speed per second.<br />
 		Note that the value and the approach speed arguments are both independently optional.<br />
-		Example:<br />
-		a,b= options:Boost() -- Sets a to the current value and b to the current approach_speed.<br />
-		a,b= options:Boost(5, .5) -- Stores the previous values in a and b, NOT to 5 and .5.  Sets the value to 5 and the approach speed to .5.<br />
-		a,b= options:Boost(5) -- Sets a and b to the previous values, NOT to 5 and .5.  Sets the value to 5 and leaves the approach speed at whatever it was.<br />
+		Example:
+<pre><code>
+-- Sets a to the current value and b to the current approach_speed
+a,b = options:Boost()
+
+-- Stores the previous values in a and b, NOT to 5 and .5
+-- Sets the value to 5 and the approach speed to .5
+a,b = options:Boost(5, .5)
+
+-- Sets a and b to the previous values, NOT to 5 and .5
+-- Sets the value to 5 and leaves the approach speed at whatever it was
+a,b = options:Boost(5)
+</code></pre>
 		<br />
 		Setting the approach speed only matters when modifying the PlayerOptions from ModsLevel_Song.<br />
 		Int type options are similar to float in that they return and take a number, but they do not have an approach speed.<br />
 		Bool type options have an almost identical interface, the difference is that they can not have an approach speed.<br />
 		Enum type options are almost identical to bool type.  They take and return an enum value.<br />
+		<!-- FIXME: These should really all have explanations. -->
 		For brevity, the functions are only given a description if the option requires careful handling or does not follow the float or bool interfaces.<br />
 	</Description>
 	<Function name='Alternate' return='float, float' arguments='float value, float approach_speed'> </Function>
@@ -3766,7 +3934,7 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 	<Function name='Flip' return='float, float' arguments='float value, float approach_speed'> </Function>
 	<Function name='Floored' return='bool' arguments='bool value'> </Function>
-	<Function name='GetStepAttacks' return='bool' argument=''>
+	<Function name='GetStepAttacks' return='bool' arguments=''>
 		Returns true if step attacks or random attacks are enabled.
 	</Function>
 	<Function name='IsEasierForCourseAndTrail' return='bool' arguments='Course c, Trail t'>
@@ -3840,11 +4008,18 @@ save yourself some time, copy this for undocumented things:
 	<Function name='NoMines' return='bool' arguments='bool value'> </Function>
 	<Function name='NoRolls' return='bool' arguments='bool value'> </Function>
 	<Function name='NoteSkin' return='string, bool' arguments='string name'>
-		Sets the NoteSkin to the named noteskin, unless name is nil or the noteskin does not exist.  Returns the name of the previous noteskin and whether the set attempt succeeded.<br />
-		Changing the noteskin during a song is not supported.<br />
-		Example:<br />
-		note_name= options:NoteSkin() -- Sets note_name to the player's current noteskin.<br />
-		prev_note_name, succeeded= options:NoteSkin("cel") -- Sets prev_note_name to the noteskin the player had set, changes the current noteskin to "cel", sets succeeded to true if the "cel" noteskin exists.<br />
+		Sets the NoteSkin to the named noteskin, unless name is <code>nil</code> or the NoteSkin does not exist.  Returns the name of the previous NoteSkin and whether the set attempt succeeded.<br />
+		Changing the NoteSkin during gameplay is not supported.<br />
+		Example:
+<pre><code>
+-- Sets note_name to the player's current noteskin
+note_name = options:NoteSkin()
+
+-- Sets prev_note_name to the noteskin the player had set
+-- changes the current noteskin to "cel"
+-- sets succeeded to true if the "cel" noteskin exists.
+prev_note_name, succeeded = options:NoteSkin("cel")
+</code></pre>
 	</Function>
 	<Function name='Overhead' return='bool' arguments='bool'>
 		If the player is using Overhead (0 tilt, 0 skew), returns true.<br />
@@ -4107,9 +4282,13 @@ save yourself some time, copy this for undocumented things:
 	<Function name='IsDisqualified' return='bool' arguments=''>
 		Returns <code>true</code> if the player was disqualified from ranking.
 	</Function>
+	<Function name='SetCurMaxScore' return='void' arguments='int maxscore'>
+	</Function>
 	<Function name='SetDancePointLimits' return='void' arguments='int actual, int possible'>
 		Sets the Dance Point limits of the stage.
 	</Function>
+	<Function name='SetScore' return='void' arguments='int score'>
+	</Function>
 </Class>
 <Class name='PlayerState'>
 	<Function name='ApplyPreferredOptionsToOtherLevels' return='void' arguments=''>
@@ -4445,6 +4624,11 @@ save yourself some time, copy this for undocumented things:
 		Sets the current stats prefix.  The stats prefix is prepended to the Stats.xml file when loading or saving a profile.  SetStatsPrefix will reload all profiles from the Stats.xml that has the given prefix.  In general, score entries are the only thing not preserved when changing the stats prefix.  Profile::HandleStatsPrefixChange in Profile.cpp lists the fields that are preserved.
 	</Function>
 </Class>
+<Class name='Quad'>
+	<Description>
+	 Quads are rectangular actors that players can see.  A Quad can have color, size, position, etc.
+	</Description>
+</Class>
 <Class name='RadarValues'>
 	<Function name='GetValue' return='int' arguments='RadarCategory rc'>
 		Returns the value of <code>rc</code> from <Link class='Steps' function='GetRadarValues' />.
@@ -4580,7 +4764,7 @@ save yourself some time, copy this for undocumented things:
 		This singleton is accessible to Lua via <code>INPUTMAN</code>.
 	</Description>
 	<Function name='GetDescriptions' return='{string}' arguments=''>
-		Return an array of connected input device descriptions.
+		Returns an array of connected input device descriptions.
 	</Function>
 </Class>
 <Class name='RageQuadratic'>
@@ -4683,29 +4867,101 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='Screen'>
+	<Description>
+		<em>Screen</em> is the base screen class containing common methods that all specialized screens inherit.<br />
+		By itself, <em>Screen</em> does not have the layers (underlay, overlay, decorations, in, out, cancel) commonly
+		used in theming, so themers designing custom screens typically use <Link class='ScreenWithMenuElements' /> as
+		the screen class for such endeavors.
+	</Description>
 	<Function name='AddInputCallback' return='void' arguments='function callback'>
-		This adds the lua function "callback" to the list of functions the screen will pass input to.  Whenever an input event occurs, callback will be passed a table with the details of the event.  callback must return a bool to indicate whether the event was handled.  If callback returns true, the event will not be passed any further.<br/>
-		This should not be used to provide text input because that would not handle localization or different keyboard layouts.<br/>
-		The screen and the callbacks will both be passed input events, so be aware of what input the current screen responds to and consider the effects.<br/>
-		Details of the table containing the event data:<br/>
-		{<br/>
-		DeviceInput= { -- The raw details of the event.<br/>
-		device= string, -- The type of device.  The first half of the string will be "Device_", the second half will be from InputDeviceNames in RageInputDevice.cpp.<br/>
-		button= string, -- The button that was pressed.  the first half of the string will be "DeviceButton_", the second half will be from InitNames in RageInputDevice.cpp.<br/>
-		level= float, -- A floating point value for analog input.<br/>
-		z= float, -- Mousewheel input.<br/>
-		down= bool, -- Whether the button is down.  This is level with a threshold and debouncing applied.<br/>
-		ago= float, -- How long ago this input occurred, in seconds.<br/>
-		is_joystick= bool, -- True if the device is a joystick.<br/>
-		is_mouse= bool -- True if the device is a mouse.<br/>
-		}, -- This ends the list of things inside the DeviceInput part of the table.<br/>
-		controller= string, -- The game controller this event was mapped to.  "GameController_1" or "GameController_2", or nil if the event wasn't mapped to either controller.<br/>
-		button= string, -- The semi-raw button that was pressed.  This is what the button was mapped to by the keymap settings, but without the conversions that occur when OnlyDedicatedMenuButtons is true.  Will be empty if the button was not mapped.<br/>
-		type= string, -- The type of event.  "InputEventType_FirstPress", "InputEventType_Repeat", or "InputEventType_Release".<br/>
-		GameButton= string, -- The cooked button that was pressed.  This is button with mapping that occurs when OnlyDedicatedMenuButtons is true applied.  This is nil for unmapped buttons.<br/>
-		PlayerNumber= PlayerNumber, -- The player that the controller is mapped to, or nil.<br/>
-		MultiPlayer= string, -- Unknown purpose.<br/>
-		}
+		This adds the Lua function <code>callback</code> to the list of functions the screen will pass input to, giving Lua access to player input as it occurs.<br />
+		When an input event occurs, <code>callback</code> will be passed a table with the details of the event.  <code>callback</code> must return a bool to indicate whether the event was handled.  If <code>callback</code> returns <code>true</code>, the event will not be passed any further.<br />
+		This method does not handle localization or different keyboard layouts, so <Link class='ScreenTextEntry' /> is better suited to getting text input from players.<br />
+		Be aware that both the screen (as handled by the StepMania engine) and your Lua callbacks will be passed input events, and this can result in undesirable side effects.<br />
+		Basic usage example:
+<pre><code>
+local InputHandler = function( event )
+	-- do something cool with the event table in here :)
+	-- the details of the event table are documented below
+
+	-- example:
+	-- show the GameButton that was most recently pressed/held
+	if event.type ~= "InputEventType_Release" then
+		SCREENMAN:SystemMessage( event.GameButton )
+	end
+
+	return false
+end
+
+Def.ActorFrame{
+	OnCommand=function(self)
+		SCREENMAN:GetTopScreen():AddInputCallback( InputHandler )
+	end
+}
+</code></pre>
+
+Details of the <code>event</code> table:
+<pre><code>
+{
+	-- The "semi-raw" button that was pressed. This is what
+	-- the button was mapped to by the keymap settings, without
+	-- the conversions that occur when OnlyDedicatedMenuButtons
+	--  is true. Will be empty if the button was not mapped.
+	button = string,
+
+	-- "InputEventType_FirstPress", "InputEventType_Repeat",
+	-- or "InputEventType_Release".
+	type = string,
+
+	-- The "cooked" button that was pressed.  This is button with
+	-- mapping that occurs when OnlyDedicatedMenuButtons is true
+	-- applied.  This is nil for unmapped buttons.
+	GameButton = string,
+
+	-- The player that the controller is mapped to, or nil.
+	PlayerNumber = PlayerNumber,
+
+	-- The game controller this event was mapped to.
+	-- "GameController_1" or "GameController_2", or nil if the event
+	-- wasn't mapped to either controller.
+	controller = string,
+
+	-- The details of the event.
+	DeviceInput = {
+		-- The type of device.  The first half of the string will
+		-- be "Device_", the second half will be from InputDeviceNames
+		-- in RageInputDevice.cpp.
+		device = string,
+
+		-- The button that was pressed. The first half of the string
+		-- will be "DeviceButton_", the second half will be from InitNames
+		-- in RageInputDevice.cpp.
+		button = string,
+
+		-- A floating point value for analog input.
+		level = float,
+
+		-- Mousewheel input.
+		z = float,
+
+		-- Whether the button is down.  This is level with a threshold
+		-- and debouncing applied.
+		down = bool,
+
+		-- How long ago this input occurred, in seconds.
+		ago = float,
+
+		-- True if the device is a joystick.
+		is_joystick = bool,
+
+		-- True if the device is a mouse.
+		is_mouse = bool
+	},
+
+	-- Unknown purpose. SMOnline?
+	MultiPlayer = string
+}
+</code></pre>
 	</Function>
 	<Function name='GetNextScreenName' return='string' arguments=''>
 		Returns the name of the next Screen.
@@ -4738,6 +4994,8 @@ save yourself some time, copy this for undocumented things:
 		[02 Other.lua] Gets a string from the current Screen in the current language.
 	</Function>
 </Class>
+<Class name='ScreenAttract'>
+</Class>
 <Class name='ScreenEdit'>
 	<Function name='GetEditState' return='EditState' arguments=''>
 		Returns the current <Link class='ENUM' function='EditState' />.
@@ -4777,19 +5035,19 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 	<Function name='HasteAddAmounts' return='{float}' arguments='{float}'>
 		This is part of the system for controlling how haste behaves. <br />
-		Read Docs/Themerdocs/haste.txt.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/haste.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/haste.txt</a>.
 	</Function>
 	<Function name='HasteLifeSwitchPoint' return='float' arguments='float'>
 		This is part of the system for controlling how haste behaves. <br />
-		Read Docs/Themerdocs/haste.txt.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/haste.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/haste.txt</a>.
 	</Function>
 	<Function name='HasteTimeBetweenUpdates' return='float' arguments='float'>
 		This is part of the system for controlling how haste behaves. <br />
-		Read Docs/Themerdocs/haste.txt.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/haste.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/haste.txt</a>.
 	</Function>
 	<Function name='HasteTurningPoints' return='{float}' arguments='{float}'>
 		This is part of the system for controlling how haste behaves. <br />
-		Read Docs/Themerdocs/haste.txt.
+		See <a href="https://github.com/stepmania/stepmania/blob/HEAD/Docs/Themerdocs/haste.txt" target="_blank" rel="noopener noreferrer">Docs/Themerdocs/haste.txt</a>.
 	</Function>
 	<Function name='SetNewScreen' return='void' arguments='string s'>
 		Sets the next Screen to be loaded.
@@ -4817,7 +5075,7 @@ save yourself some time, copy this for undocumented things:
 		Gets the screen at the top of the screen stack.
 	</Function>
 	<Function name='get_input_redirected' return='bool' arguments='PlayerNumber pn'>
-		Returns whether the input for the player has been redirected away from the normal screen input function.  Input that has been redirected is only sent to lua input callbacks.
+		Returns whether the input for the player has been redirected away from the normal screen input function.  Input that has been redirected is only sent to Lua input callbacks.
 	</Function>
 	<Function name='PlayInvalidSound' return='' arguments=''>
 		Plays the invalid sound.
@@ -4847,8 +5105,8 @@ save yourself some time, copy this for undocumented things:
 		Sets the next screen to <code>s</code>.
 	</Function>
 	<Function name='set_input_redirected' return='bool' arguments='PlayerNumber pn, bool redir'>
-		Sets whether the input for the player has been redirected away from the normal screen input function.  Input that has been redirected is only sent to lua input callbacks.<br />
-		This can be useful when putting a custom menu on a screen, and you want to disable the built in actors while the menu is open.  Then you handle input through an input callback until the player closes the menu.
+		Sets whether the input for the player has been redirected away from the normal screen input function.  Input that has been redirected is only sent to Lua input callbacks.<br />
+		This can be useful when putting a custom menu on a screen, and you want to disable the built in actors while the menu is open.  You can handle input through an <Link class='Screen' function='AddInputCallback'>input callback</Link> until the player closes the menu.
 	</Function>
 	<Function name='SystemMessage' return='void' arguments='string s'>
 		Broadcasts a system message.
@@ -4887,6 +5145,12 @@ save yourself some time, copy this for undocumented things:
 		Returns the number of active players.
 	</Function>
 </Class>
+<Class name='ScreenNetRoom'>
+</Class>
+<Class name='ScreenNetSelectBase'>
+</Class>
+<Class name='ScreenNetSelectMusic'>
+</Class>
 <Class name='ScreenOptions'>
 	<Function name='AllAreOnLastRow' return='bool'  arguments=''>
 		Returns <code>true</code> if all active players are on the last options row.
@@ -4962,18 +5226,76 @@ save yourself some time, copy this for undocumented things:
 		Returns the profile index of the specified Player.
 	</Function>
 	<Function name='SetProfileIndex' return='bool' arguments='PlayerNumber pn, int iProfileIndex'>
-		Sets the profile index of Player <code>pn</code> to <code>iProfileIndex</code>.<br/>
-		The following values of <code>iProfileIndex</code> have special, hardcoded behavior:<br/>
-		• <code>-1</code>: join the player and play the theme's start sound effect<br/>
+		Sets the profile index of Player <code>pn</code> to <code>iProfileIndex</code>.<br />
+		The following values of <code>iProfileIndex</code> have special, hardcoded behavior:<br />
+		• <code>-1</code>: join the player and play the theme's start sound effect<br />
 		• <code>-2</code>: unjoin the player, unlock their MemoryCard, and unmount their MemoryCard
 	</Function>
 </Class>
 <Class name='ScreenTextEntry'>
 	<Description>
-		TextEntrySettings is implemented similar to the Attributes in BitmapText. Formatting issues prevent the sample from being properly shown here.<br />Please see docs/Themerdocs/ScreenTextEntry.txt for the TextEntrySettings format.
+		Using ScreenTextEntry is the preferred way to get text input from players.<br />
+		For theming, ScreenTextEntry is unique because it is typically added temporarily to the engine's
+		screen stack to be popped off the stack when the player is done entering text.<br />
+		As such, it is commonly styled to appear to players as an overlay or modal.<br />
+		Basic usage example:
+<pre><code>
+local args = {
+	Question="Do you like Waffles?",
+	InitialAnswer="Yeah, we like waffles!",
+	MaxInputLength=300,
+	OnOK=function(answer)
+		-- answer is what the player typed
+		local msg = "Your response was: " .. answer
+		SCREENMAN:SystemMessage(msg)
+	end
+}
+
+SCREENMAN:AddNewScreenToTop("ScreenTextEntry")
+SCREENMAN:GetTopScreen():Load( args )
+</code></pre>
 	</Description>
 	<Function name='Load' return='void' arguments='TextEntrySettings args'>
-		Sets up a ScreenTextEntry's values.
+		Sets up a ScreenTextEntry's values using <code>args</code>.<br />
+		TextEntrySettings is special struct for ScreenTextEntry, and
+		as a Lua table, it should contain specific attributes:
+<pre><code>
+local args = {
+	-- ScreenMessage to send on pop
+	-- optional, "SM_None" if omitted
+	SendOnPop = "",
+
+	-- the question text to display
+	Question = "",
+
+	-- initial answer text
+	InitialAnswer = "",
+
+	-- Maximum amount of characters
+	MaxInputLength = 0,
+
+	-- mask character input (optional)
+	Password = false,
+
+	-- validation function
+	-- must return boolean and string
+	Validate = function(answer, errorStr) end,
+
+	-- function called on ok
+	OnOK = function(answer) end,
+
+	-- function called on cancel
+	OnCancel = function() end,
+
+	-- Validate appending a character <!-- what does this mean? -quietly -->
+	-- must return boolean
+	ValidateAppend = function(answer, append) end,
+
+	-- Format answer for display
+	-- must return string
+	FormatAnswerForDisplay = function(answer) end
+}
+</code></pre>
 	</Function>
 </Class>
 <Class name='ScreenWithMenuElements'>
@@ -4990,26 +5312,32 @@ save yourself some time, copy this for undocumented things:
 		Sets whether the screen allows late joining.  This only works for screens that are just ScreenWithMenuElements, as most derived screens have their own hard coded function for whether late joining is allowed.
 	</Function>
 </Class>
+<Class name='ScreenWithMenuElementsSimple'>
+</Class>
 <Class name='Song'>
 	<Function name='GetAllSteps' return='{Steps}' arguments=''>
 		Returns an array of all the available <Link class='Steps' /> objects for a <Link class='Song' />.
 	</Function>
 	<Function name='GetBackgroundPath' return='string' arguments=''>
-		Returns the path to the song's background image.
+		Returns the path to the song's background image.<br />
+		If the stepartist did not provide a path for a background, this returns <code>nil</code>.
 	</Function>
 	<Function name='GetBannerPath' return='string' arguments=''>
-		Returns the path to the song's banner.
+		Returns the path to the song's banner.<br />
+		If the stepartist did not provide a path for a banner, this returns <code>nil</code>.
 	</Function>
 	<Function name='GetBGChanges' return='table' arguments=''>
 		Returns a table with all the data for the song's BGCHANGES line.<br />
 		Each element of the table is one change like this:<br />
-		{start_beat= 1.0, rate= 1.0, transition= "example", effect= "example", file1= "example", file2= "example", color1= "#FFFFFFFF", color2= "#FFFFFFFF"}
+		<code>{start_beat=1.0, rate=1.0, transition="example", effect="example", file1="example", file2="example", color1="#FFFFFFFF", color2="#FFFFFFFF"}</code>
 	</Function>
 	<Function name='GetCDImagePath' return='string' arguments=''>
-		Returns the path to the song's CD image.
+		Returns the path to the song's CD image.<br />
+		If the stepartist did not provide a path for a CDImage, this returns <code>nil</code>.
 	</Function>
 	<Function name='GetCDTitlePath' return='string' arguments=''>
-		Gets the path to the CDTitle.
+		Gets the path to the CDTitle.<br />
+		If the stepartist did not provide a path for a CDTitle, this returns <code>nil</code>.
 	</Function>
 	<Function name='GetDiscPath' return='string' arguments=''>
 		Returns the path to the song's disc image (different from CD, think Pump).
@@ -5021,13 +5349,17 @@ save yourself some time, copy this for undocumented things:
 		Returns a table of 2 floats containing the display BPMs.
 	</Function>
 	<Function name='GetDisplayFullTitle' return='string' arguments=''>
-		Returns the displayed full title of the song, including subtitle.
+		Returns the displayed full title of the song.<br />
+		The full title is, at minimum, the main title.
+		If the <Link class='Song' function='GetDisplaySubTitle'>subtitle</Link> is not an empty string,
+		the full title is main title + " " + subtitle.
 	</Function>
 	<Function name='GetDisplayMainTitle' return='string' arguments=''>
 		Returns the displayed main title of the song.
 	</Function>
 	<Function name='GetDisplaySubTitle' return='string' arguments=''>
-		Returns the displayed subtitle of the song.
+		Returns the displayed subtitle of the song.<br />
+		If the stepartist did not provide a subtitle, this returns an empty string.
 	</Function>
 	<Function name='GetFirstBeat' return='float' arguments=''>
 		Returns the first beat of the song.
@@ -5224,8 +5556,8 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetCoursesInGroup' return='{Course}' arguments='string sGroup, bool bIncludeAutogen'>
 		Returns a table with all of the courses in the specified group.
 	</Function>
-	<Function name='GetExtraStageInfo' return='various' arguments='bool bExtra2, Style s'>
-		Returns the extra stage info (Song, Steps) for the specified Style <code>s</code>. (If <code>bExtra2</code> is true, it will use the second Extra Stage data instead of the first. Again, Lua.xsd sucks)
+	<Function name='GetExtraStageInfo' return='various' arguments='bool b2ndExtra, Style s'>
+		Returns the extra stage info (Song, Steps) for the specified Style <code>s</code>. If <code>b2ndExtra</code> is true, it will use the second Extra Stage data instead of the first.
 	</Function>
 	<Function name='GetNumAdditionalCourses' return='int' arguments=''>
 		Returns the number of courses loaded via Additional folders.
@@ -5370,6 +5702,25 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='Sprite'>
+	<Description>
+		<em>Sprite</em> actors can be used to display images and video.  If you want to load a png as part of your UI,
+		or animate a visual effect from a sprite sheet, or play a video file, <em>Sprite</em> is what you're looking for.<br />
+		<br />
+		You can initialize <em>Sprite</em>s with a filepath to the graphic asset using their <code>Texture</code> attribute.
+<pre><code>
+local spr = Def.Sprite{
+	Texture="path/to/mycoolimage.png"
+}
+</code></pre>
+	Frame-based animated sprites can be initialized with the <code>Frames</code> attribute.
+<pre><code>
+local spr = Def.Sprite{
+	Texture="path/to/Spikes 6x3.png",
+	Frames=Sprite.LinearFrames(18, 1)
+}
+</code></pre>
+
+	</Description>
 	<Function name='GetAnimationLengthSeconds' return='float' arguments=''>
 		Returns the length of the animation in seconds.
 	</Function>
@@ -5386,7 +5737,8 @@ save yourself some time, copy this for undocumented things:
 		Returns the Sprite's texture.
 	</Function>
 	<Function name='LinearFrames' theme='_fallback' return='table' arguments='int iNumFrames, float fSeconds'>
-		[02 Sprite.lua] Returns a <code>Frames</code> table consisting of <code>iNumFrames</code> frames lasting for a total of <code>fSeconds</code> seconds. This function is not a member function and should be used as <code>Frames = Sprite.LinearFrames( 5, 2.6 )</code>.
+		[02 Sprite.lua] Returns a <code>Frames</code> table consisting of <code>iNumFrames</code> frames lasting for a total of <code>fSeconds</code> seconds.<br />
+		This function is not a member function and should be used as <code>Frames = Sprite.LinearFrames( 5, 2.6 )</code>.
 	</Function>
 	<Function name='Load' return='void' arguments='string sPath'>
 		If <code>sPath</code> is <code>nil</code>, then unload the texture. Otherwise, load the texture at path <code>sPath</code>.
@@ -5429,19 +5781,29 @@ save yourself some time, copy this for undocumented things:
 	<Function name='SetSecondsIntoAnimation' return='void' arguments='float fSeconds'>
 		Sets the number of seconds into the animation to <code>fSeconds</code>.
 	</Function>
-	<Function name='SetStateProperties' return= '' arguments='table properties'>
+	<Function name='SetStateProperties' return= 'void' arguments='table properties'>
 		Sets the properties of the states of the sprite.  The properties table is identical to the "Frames" table that can be put in the sprite when calling Def.Sprite.<br />
-		Example:<br />
-		{{Frame= 0, Delay= .016, {0, 0}, {.25, .25}},<br />
-		{Frame= 1, Delay= .016, {0, 0}, {.25, .25}},<br />
-		{Frame= 2, Delay= .016, {0, 0}, {.25, .25}},<br />
-		{Frame= 3, Delay= .016, {0, 0}, {.25, .25}},<br />
-		}<br />
-		Frame is optional, defaulting to 0.<br />
-		Delay is optional, defaulting to 0.<br />
+		Example:
+<pre><code>
+{
+	{ Frame=0, Delay=0.333, {0, 0}, {.25, .25} },
+	{ Frame=1, Delay=0.333, {0, 0}, {.25, .25} },
+	{ Frame=2, Delay=0.333, {0, 0}, {.25, .25} },
+	{ Frame=3, Delay=0.333, {0, 0}, {.25, .25} },
+}
+</code></pre>
+		<code>Frame</code> is optional, defaulting to 0.<br />
+		<code>Delay</code> is optional, defaulting to 0.<br />
 		The two tables are optional upper left and lower right corners of the fraction of the frame to use.  The example makes the sprite only use the upper left corner of each frame.<br />
-		Simpler example:<br />
-		{{Frame= 0, Delay= .016}, {Frame= 1, Delay= .016}, {Frame= 2, Delay= .016}, {Frame= 3, Delay= .016}}<br />
+		Simpler example:
+<pre><code>
+{
+	{Frame=0, Delay=0.333},
+	{Frame=1, Delay=0.333},
+	{Frame=2, Delay=0.333},
+	{Frame=3, Delay=0.333}
+}
+</code></pre>
 		This example makes the sprite use the whole of each frame.
 	</Function>
 	<Function name='SetTexture' return='void' arguments='RageTexture texture'>
@@ -5656,11 +6018,11 @@ save yourself some time, copy this for undocumented things:
 		Returns the StyleType for this Style.
 	</Function>
 	<Function name='GetColumnInfo' return='{int, int, string}' arguments='PlayerNumber pn, int column'>
-		Returns a table containing the <code>Track</code>, <code>XOffset</code>, and <code>Name</code> of the column.<br/>
+		Returns a table containing the <code>Track</code>, <code>XOffset</code>, and <code>Name</code> of the column.<br />
 		For example, calling <code>GAMESTATE:GetCurrentStyle():GetColumnInfo('PlayerNumber_P1', 2)</code> when the current
-		game is dance will return <code>{Track=2, XOffset=-32, Name="Down"}</code>.<br/>
+		game is dance will return <code>{Track=2, XOffset=-32, Name="Down"}</code>.<br />
 		Calling <code>GAMESTATE:GetCurrentStyle():GetColumnInfo('PlayerNumber_P1', 1)</code> when the current
-		game is pump will return <code>{Track=1, XOffset=-96, Name="DownLeft"}</code>.<br/>
+		game is pump will return <code>{Track=1, XOffset=-96, Name="DownLeft"}</code>.<br />
 	</Function>
 	<Function name='GetColumnDrawOrder' return='int' arguments='int column'>
 		Returns the draw order of the column.
@@ -5719,7 +6081,7 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 <Class name='HoldNoteResult'>
-	<Function name='GetHoldNoteScore'>
+	<Function name='GetHoldNoteScore' return='HoldNoteScore' arguments=''>
 		Returns the <Link class='HoldNoteScore' /> of the Hold Note.
 	</Function>
 	<Function name='GetLife' return='float' arguments=''>
@@ -5795,8 +6157,10 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetPathG' return='string' arguments='string ClassName, string Element'>
 		Returns the path of an element in the Graphics folder.
 	</Function>
-	<Function name='GetPathInfoB' return='string' arguments='string ClassName, string Element'>
-		returns three strings: BGAnimation ResolvedPath, MatchingMetricsGroup, MatchingElement. Used in <Link class='GLOBAL' function='LoadFallbackB'>LoadFallbackB</Link> in themes/_fallback/02 Other.lua. (Lua.xsd sucks)
+	<Function name='GetPathInfoB' return='string, string, string' arguments='string ClassName, string Element'>
+		Returns three strings: BGAnimation ResolvedPath, MatchingMetricsGroup, MatchingElement.<br />
+		Used in <Link class='GLOBAL' function='LoadFallbackB'>LoadFallbackB</Link> in themes/_fallback/02 Other.lua<br />
+		Example: <code>local path, metrics_group, element = THEME:GetPathInfoB("ScreenTitleJoin", "decorations")</code>
 	</Function>
 	<Function name='GetPathO' return='string' arguments='string ClassName, string Element'>
 		Returns the path of an element in the Other folder.
@@ -5819,6 +6183,16 @@ save yourself some time, copy this for undocumented things:
 	<Function name='GetThemeDisplayName' return='string' arguments=''>
 		Returns the display name of the current theme.
 	</Function>
+	<Function name='get_theme_fallback_list' return='{ string }' arguments=''>
+		Returns a table of strings showing what themes the current theme falls back on.<br />
+		For example, if the current theme is in a folder named "Home", and the "Home" theme falls back on the "default" theme, which itself falls back on the "_fallback" theme, the table would be:
+<pre><code>
+{
+	[1]="Home",
+	[2]="default",
+	[3]="_fallback"
+}</code></pre>
+	</Function>
 	<Function name='HasMetric' return='bool' arguments='string section, string value'>
 		Returns <code>true</code> if the theme has the specified metric.
 	</Function>
@@ -5843,19 +6217,24 @@ save yourself some time, copy this for undocumented things:
 <Class name='TimingData'>
 	<Description>
 		GetBPMsAndTimes, GetStops, GetDelays, GetLabels, GetWarps, GetCombos, GetTimeSignatures, GetTickcounts, GetFakes, GetScrolls, and GetSpeeds all have two different modes.<br />
-		If false (or nothing) is the argument to these functions, they return tables of strings.  The strings are numbers separated by '='.<br />
-		If the argument is true, they return tables of tables, and the inner tables contain numbers as described for each function.<br />
-		The first form is kept around and is the default for compatibility with older themes.  The advantage of the second form is that you no longer need to have a bit of code in your theme to transform the string into a table of numbers before you can use it.<br />
-		Example:<br />
-		local bpmsand= timing_data:GetBPMsAndTimes()<br />
-		for i, s in ipairs(bpmsand) do<br />
-		local sand= split("=", s)<br />
-		bpmsand[i]= {tonumber(sand[1]), tonumber(sand[2])}<br />
-		end<br />
-		-- do something that looks at all the bpms and times. <br />
-		Becomes:<br />
-		local bpmsand= timing_data:GetBPMsAndTimes(true)<br />
-		-- do something that looks at all the bpms and times. <br />
+		If <code>false</code> (or nothing) is the argument to these functions, they return tables of strings.  The strings are numbers separated by '='.<br />
+		If the argument is <code>true</code>, they return tables of tables, and the inner tables contain numbers as described for each function.<br />
+		The first form is kept as the default to maintain compatibility with older themes.  The second form can be convenient because there is no need to transform the string into a table of numbers before using it.<br />
+		Example of first form:
+<pre><code>
+local bpms_and_times = timing_data:GetBPMsAndTimes()
+for i, s in ipairs(bpms_and_times) do
+	local bpm_and_time = split("=", s)
+	bpms_and_times[i] = {tonumber(bpm_and_time[1]), tonumber(bpm_and_time[2])}
+end
+-- do something with the bpms and times now that they are numbers.
+</code></pre>
+		<br />
+		Example of second form:
+<pre><code>
+local bpms_and_times = timing_data:GetBPMsAndTimes(true)
+-- do something with the bpms and times because they are already numbers.
+</code></pre>
 	</Description>
 	<Function name='GetActualBPM' return='{float}' arguments=''>
 		Returns the minimum and maximum BPM of the song in a table (in that order).
@@ -6148,6 +6527,7 @@ save yourself some time, copy this for undocumented things:
 	</Function>
 </Class>
 </Classes>
+
 <!-- Enums -->
 <Enums>
 <Description>

From 5574113d632dca6eee309411b73706b4b8db0bde Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Thu, 25 Jun 2020 05:06:16 -0400
Subject: [PATCH 60/65] tidy preformatted code examples in LuaDoc

---
 Docs/Luadoc/LuaDocumentation.xml | 39 +++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 16 deletions(-)

diff --git a/Docs/Luadoc/LuaDocumentation.xml b/Docs/Luadoc/LuaDocumentation.xml
index 8de4ee0a4a..3532861279 100644
--- a/Docs/Luadoc/LuaDocumentation.xml
+++ b/Docs/Luadoc/LuaDocumentation.xml
@@ -789,6 +789,14 @@ save yourself some time, copy this for undocumented things:
 
 <!-- Namespaces -->
 <Namespaces>
+<Description>
+	The StepMania engine makes some of its namespaces available to Lua.  These can be thought of as collections of utility functions.<br />
+	Example using <code>SongUtil</code> to get playable <Link class='Steps' /> from a song given the current <Link class='Game' />:
+<pre><code>
+local song = GAMESTATE:GetCurrentSong()
+local playable_steps = SongUtil.GetPlayableSteps(song)
+</code></pre>
+</Description>
 <Namespace name='ActorUtil'>
 	<Function name='GetFileType' return='FileType' arguments='string sPath'>
 		Returns the <Link class='ENUM' function='FileType' /> for the file at <code>sPath</code>.
@@ -864,20 +872,17 @@ save yourself some time, copy this for undocumented things:
 	<Description>
 		Enumerated types are lookup tables associating a string to each numerical
 		value for each <Link class='Enums'>Enum</Link>. For example,
-		<code><Link class='ENUM' function='PlayerNumber' />[1]</code> would be the
+		<code>PlayerNumber[1]</code> would be the
 		string <code>'PlayerNumber_P1'</code>.<br />
-		The functions defined in the <code>Enum</code> namespace are valid member
+		The functions in this <code>Enum</code> namespace are valid member
 		functions of every <Link class='Enums'>Enum</Link> where the first argument is
-		omitted and the name of the <Link class='Enums'>Enum</Link> is used in place
-		of <code>Enum</code>. Instead of
-		<code><Link function='GetName'>Enum.GetName</Link>(
-		<Link class='ENUM' function='PlayerNumber' /> )</code> or
-		<code><Link function='Reverse'>Enum.Reverse</Link>(
-		<Link class='ENUM' function='PlayerNumber' /> )</code>, one can use
-		<code><Link class='ENUM' function='PlayerNumber' />:<!--
-		--><Link function='GetName'>GetName</Link>()</code> or
-		<code><Link class='ENUM' function='PlayerNumber' />:<!--
-		--><Link function='Reverse'>Reverse</Link>()</code>, respectively.
+		omitted and the name of the Enum is used in place
+		of <code>Enum</code>.<br />
+		For example:<br />
+		<code>Enum.GetName(PlayerNumber)</code> and
+		<code>Enum.Reverse(PlayerNumber)</code> can be used like<br />
+		<code>PlayerNumber:GetName()</code> and
+		<code>PlayerNumber:Reverse()</code>, respectively.
 	</Description>
 	<Function name='Compare' return='int' arguments='Enum e, string x, string y'>
 		Both <code>x</code> and <code>y</code> need to be elements of the enumerated
@@ -893,10 +898,12 @@ save yourself some time, copy this for undocumented things:
 		will return the string <code>'PlayerNumber'</code>.
 	</Function>
 	<Function name='Reverse' return='{int}' arguments='Enum e'>
-		Returns a reverse lookup table for the enumerated type <code>e</code>.  For
-		example: <br /><code>local r =
-		Enum.Reverse( <Link class='ENUM' function='PlayerNumber'/> );<br />
-		local n = r['PlayerNumber_P2'];</code><br />
+		Returns a reverse lookup table for the enumerated type <code>e</code>. For
+		example:
+<pre><code>
+local r = PlayerNumber:Reverse()
+local n = r['PlayerNumber_P2']
+</code></pre>
 		The value of <code>n</code> in this case would be <code>1</code> corresponding
 		to the 0-based indexing using in C++ and not <code>2</code> as might be
 		expected for the 1-based indexing used in Lua.

From 4635973799511de2008897e9afecb4f214f4aedd Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Thu, 25 Jun 2020 05:10:25 -0400
Subject: [PATCH 61/65] add grouping attr to Class elements in LuaDoc

These "grouping"s aren't part of the spec in Docs/Luadoc/Lua.xsd, so
they won't appear when Lua.xml is viewed in a web browser, but can still
be used by external API doc applications until ExportLuaInformation is
improved.
---
 Docs/Luadoc/LuaDocumentation.xml | 167 ++++++++++++++++++++-----------
 1 file changed, 111 insertions(+), 56 deletions(-)

diff --git a/Docs/Luadoc/LuaDocumentation.xml b/Docs/Luadoc/LuaDocumentation.xml
index 3532861279..46e085c629 100644
--- a/Docs/Luadoc/LuaDocumentation.xml
+++ b/Docs/Luadoc/LuaDocumentation.xml
@@ -980,7 +980,7 @@ local n = r['PlayerNumber_P2']
 
 <!-- Classes -->
 <Classes>
-<Class name='Actor'>
+<Class name='Actor' grouping='Actor'>
 	<Description>
 		<em>Actor</em> is the base class containing common methods that all specialized actor classes inherit.
 		For example, <Link class='Actor' function='GetX'>GetX</Link> is a method belonging to <em>Actor</em>,
@@ -1611,7 +1611,7 @@ local n = r['PlayerNumber_P2']
 		Sets the x and y location of the Actor in one command.
 	</Function>
 </Class>
-<Class name='ActorFrame'>
+<Class name='ActorFrame' grouping='Actor'>
 	<Description>
 		ActorFrames are containers that allow multiple children actors to be grouped and scripted together.<br />
 		In theming, the StepMania engine expects a screen layer (underlay, overlay, decorations, in, out, cancel)
@@ -1756,7 +1756,7 @@ return af
 		Sets the vanishing point for the ActorFrame.
 	</Function>
 </Class>
-<Class name='ActorFrameTexture'>
+<Class name='ActorFrameTexture' grouping='Actor'>
 	<Function name='Create' return='void' arguments=''>
 		Creates the ActorFrameTexture.
 	</Function>
@@ -1779,7 +1779,7 @@ return af
 		Sets the Texture's name to <code>sName</code>.
 	</Function>
 </Class>
-<Class name='ActorMultiTexture'>
+<Class name='ActorMultiTexture' grouping='Actor'>
 	<Function name='AddTexture' return='int' arguments='RageTexture tex'>
 		Adds a texture to the ActorMultiTexture. Returns the number of texture units.
 	</Function>
@@ -1799,7 +1799,7 @@ return af
 		Sets a TextureMode on the specified index.
 	</Function>
 </Class>
-<Class name='ActorMultiVertex'>
+<Class name='ActorMultiVertex' grouping='Actor'>
 	<Function name='AddQuadState' return='' arguments='int offset'>
 		The list of quad states is used to determine which animation state is used for each quad.  The offset is added to the AMV's current state, and the resulting state is used.
 	</Function>
@@ -1948,7 +1948,7 @@ self:SetDrawState{First= 3, Num= 4}
 		Sets the texture at from the file path <code>path</code>.
 	</Function>
 </Class>
-<Class name='ActorProxy'>
+<Class name='ActorProxy' grouping='Actor'>
 	<Function name='GetTarget' return='Actor' arguments=''>
 		Returns the target of the ActorProxy.
 	</Function>
@@ -1956,7 +1956,7 @@ self:SetDrawState{First= 3, Num= 4}
 		Sets the ActorProxy target to <code>a</code>.
 	</Function>
 </Class>
-<Class name='ActorScroller'>
+<Class name='ActorScroller' grouping='Actor'>
 	<Function name='GetCurrentItem' return='float' arguments=''>
 		Returns the scroller's current item.
 	</Function>
@@ -2043,7 +2043,7 @@ self:SetDrawState{First= 3, Num= 4}
 		Sets the scroller's transform function from <code>fItemWidth</code>.
 	</Function>
 </Class>
-<Class name='ActorSound'>
+<Class name='ActorSound' grouping='Actor'>
 	<Description>
 		This actor represents a playable sound.  Though the C++ class is ActorSound, it is accessible to Lua via <code>Def.Sound</code>.<br />
 		You must provide <em>ActorSound</em>s with a filepath to the asset using their <code>File</code> attribute.
@@ -2123,7 +2123,7 @@ Def.Sound{
 		Returns the name of the architecture in use.
 	</Function>
 </Class>
-<Class name='Banner'>
+<Class name='Banner' grouping='Actor'>
 	<Function name='GetScrolling' return='bool' arguments=''>
 		Returns <code>true</code> if the Banner is currently scrolling.
 	</Function>
@@ -2167,7 +2167,7 @@ Def.Sound{
 		<!-- todo -->
 	</Function>
 </Class>
-<Class name='BitmapText'>
+<Class name='BitmapText' grouping='Actor'>
 	<Description>
 		<em>BitmapText</em> actors are used to display text on-screen.<br />
 		The font can be specified using the <code>Font</code> attribute. It takes a font name a string,
@@ -2288,7 +2288,7 @@ Def.BitmapText{
 		Wrap the unzoomed text at <code>iWidth</code> pixels. If you <Link class='Actor' function='zoom' /> or <Link class='Actor' function='zoomx' /> by <code>x</code> and you want the text wrapped at <code>width</code>, then you should use <code>wrapwidthpixels(width/x)</code>.
 	</Function>
 </Class>
-<Class name='BPMDisplay'>
+<Class name='BPMDisplay' grouping='Actor'>
 	<Function name='GetText' return='string' arguments=''>
 		Returns the text that is currently set at the exact moment you call it. This is likely only going to be useful in an Update command.
 	</Function>
@@ -2357,7 +2357,7 @@ Def.BitmapText{
 		Returns the number of characters available.
 	</Function>
 </Class>
-<Class name='ComboGraph'>
+<Class name='ComboGraph' grouping='Actor'>
 	<Function name='Load' return='void' arguments='string sMetricsGroup'>
 		Loads the ComboGraph commands from the Metrics in group <code>sMetricsGroup</code>.
 	</Function>
@@ -2365,7 +2365,7 @@ Def.BitmapText{
 		Sets the values of the ComboGraph using the specified StageStats and PlayerStageStats.
 	</Function>
 </Class>
-<Class name='ControllerStateDisplay'>
+<Class name='ControllerStateDisplay' grouping='Actor'>
 	<Function name='LoadGameController' return='void' arguments='string sType, GameController gc'>
 		Loads the ControllerStateDisplay from the specified GameController.
 	</Function>
@@ -2459,7 +2459,7 @@ Def.BitmapText{
 		Returns <code>true</code> if the Course is a ranking course.
 	</Function>
 </Class>
-<Class name='CourseContentsList'>
+<Class name='CourseContentsList' grouping='Actor'>
 	<Function name='SetFromGameState' return='void' arguments=''>
 		Sets the CourseContentsList from the GameState.
 	</Function>
@@ -2597,13 +2597,13 @@ Def.BitmapText{
 		Destroys the spline, freeing the memory allocated for it.  This can only be called on splines created with create_spline().
 	</Function>
 </Class>
-<Class name='DeviceList'>
+<Class name='DeviceList' grouping='Actor'>
 	<Description>
 		A newline-delimited list of available input devices.<br />
 		The list shown will the same as that returned by <Link class='RageInput' function='GetDescriptions'>INPUTMAN:GetDescriptions()</Link>, but with "MonkeyKeyboard" removed.
 	</Description>
 </Class>
-<Class name='DifficultyIcon'>
+<Class name='DifficultyIcon' grouping='Actor'>
 	<Function name='SetFromDifficulty' return='void' arguments='Difficulty dc'>
 		Sets the DifficultyIcon's state from the difficulty passed in.
 	</Function>
@@ -2677,7 +2677,7 @@ Def.BitmapText{
 	<Function name='__tostring' return='string' arguments=''>
 	</Function>
 </Class>
-<Class name='FadingBanner'>
+<Class name='FadingBanner' grouping='Actor'>
 	<Function name='GetLatestIndex' return='int' arguments=''>
 		Returns the index of the last banner loaded.
 	</Function>
@@ -2718,7 +2718,7 @@ Def.BitmapText{
 		See <Link class='Sprite' function='scaletoclipped' />.
 	</Function>
 </Class>
-<Class name='StepsDisplayList'>
+<Class name='StepsDisplayList' grouping='Actor'>
 	<Function name='setfromgamestate' return='void' arguments=''>
 		Sets the StepsDisplayList from the GameState.
 	</Function>
@@ -3268,7 +3268,7 @@ end
 		Unjoins player <code>pn</code>.
 	</Function>
 </Class>
-<Class name='GradeDisplay'>
+<Class name='GradeDisplay' grouping='Actor'>
 	<Function name='Load' return='void' arguments='string sMetricsGroup'>
 		Loads the GradeDisplay commands from the Metrics in group <code>sMetricsGroup</code>.
 	</Function>
@@ -3276,7 +3276,7 @@ end
 		Sets the GradeDisplay to show Grade <code>g</code>.
 	</Function>
 </Class>
-<Class name='GraphDisplay'>
+<Class name='GraphDisplay' grouping='Actor'>
 	<Function name='Load' return='void' arguments='string sMetricsGroup'>
 		Loads the GraphDisplay commands from the Metrics in group <code>sMetricsGroup</code>.
 	</Function>
@@ -3284,7 +3284,7 @@ end
 		Sets the values of the GraphDisplay using the specified StageStats and PlayerStageStats.
 	</Function>
 </Class>
-<Class name='GrooveRadar'>
+<Class name='GrooveRadar' grouping='Actor'>
 	<Function name='SetEmpty' return='void' arguments='PlayerNumber pn'>
 		Sets the GrooveRadar values for Player <code>pn</code> to empty.
 	</Function>
@@ -3295,7 +3295,7 @@ end
 		Sets the GrooveRadar values for Player <code>pn</code> to the specified (floating point) values in the table.
 	</Function>
 </Class>
-<Class name='HelpDisplay'>
+<Class name='HelpDisplay' grouping='Actor'>
 	<Function name='gettips' return='{string}' arguments=''>
 		Returns two tables representing the tips and alternate tips in the HelpDisplay.
 	</Function>
@@ -3370,7 +3370,7 @@ end
 		Returns the rank of the highest score for name in the list.  Returns 0 if there is no score for name in the list.  (returns 1 if name has the top score, 2 if name has the second place score, and so on)
 	</Function>
 </Class>
-<Class name='HoldJudgment'>
+<Class name='HoldJudgment' grouping='Actor'>
 	<Function name='LoadFromMultiPlayer' return='void' arguments='MultiPlayer mp'>
 		Loads the HoldJudgment for the specified MultiPlayer.
 	</Function>
@@ -3389,7 +3389,7 @@ end
 		Returns the Y position of the mouse.
 	</Function>
 </Class>
-<Class name='InputList'>
+<Class name='InputList' grouping='Actor'>
 	<Description>
 		A newline-delimited list of inputs that are currently being pressed.  It will update as inputs are held and released.  Handy for custom TestInput screens.
 	</Description>
@@ -3479,12 +3479,12 @@ end
 		Sets whether logging of messages is enabled.  If log is true, all messages that pass through Broadcast (from the engine for from the theme or from anywhere else), will be logged with Trace.
 	</Function>
 </Class>
-<Class name='MeterDisplay'>
+<Class name='MeterDisplay' grouping='Actor'>
 	<Function name='SetStreamWidth' return='void' arguments='float fWidth'>
 		Sets the width of the MeterDisplay to <code>fWidth</code>.
 	</Function>
 </Class>
-<Class name='Model'>
+<Class name='Model' grouping='Actor'>
 	<Function name='GetDefaultAnimation' return='string' arguments=''>
 		Returns the model's default animation.
 	</Function>
@@ -3508,7 +3508,7 @@ end
 		Returns the number of states the Model has.
 	</Function>
 </Class>
-<Class name='ModIconRow'>
+<Class name='ModIconRow' grouping='Actor'>
 	<Function name='Load' return='void' arguments='string sMetricsGroup, PlayerNumber pn'>
 		Loads the ModIconRow of Player <code>pn</code> from the Metrics in group <code>sMetricsGroup</code>.
 	</Function>
@@ -3716,12 +3716,12 @@ end
 		Returns <code>true</code> if this row forces one choice on all players.
 	</Function>
 </Class>
-<Class name='PaneDisplay'>
+<Class name='PaneDisplay' grouping='Actor'>
 	<Function name='SetFromGameState' return='void' arguments=''>
 		Sets the PaneDisplay from the GameState.
 	</Function>
 </Class>
-<Class name='PercentageDisplay'>
+<Class name='PercentageDisplay' grouping='Actor'>
 	<Function name='LoadFromStats' return='void' arguments='PlayerState pPlayerState, PlayerStageStats pPlayerStageStats'>
 		Sets the PercentageDisplay from the specified PlayerState and PlayerStageStats.
 	</Function>
@@ -4631,7 +4631,7 @@ prev_note_name, succeeded = options:NoteSkin("cel")
 		Sets the current stats prefix.  The stats prefix is prepended to the Stats.xml file when loading or saving a profile.  SetStatsPrefix will reload all profiles from the Stats.xml that has the given prefix.  In general, score entries are the only thing not preserved when changing the stats prefix.  Profile::HandleStatsPrefixChange in Profile.cpp lists the fields that are preserved.
 	</Function>
 </Class>
-<Class name='Quad'>
+<Class name='Quad' grouping='Actor'>
 	<Description>
 	 Quads are rectangular actors that players can see.  A Quad can have color, size, position, etc.
 	</Description>
@@ -4865,7 +4865,7 @@ prev_note_name, succeeded = options:NoteSkin("cel")
 		Reloads the texture.
 	</Function>
 </Class>
-<Class name='RollingNumbers'>
+<Class name='RollingNumbers' grouping='Actor'>
 	<Function name='Load' return='void' arguments='string sGroupName'>
 		Loads the metrics for this RollingNumbers from <code>sGroupName</code>.
 	</Function>
@@ -4873,7 +4873,7 @@ prev_note_name, succeeded = options:NoteSkin("cel")
 		Sets the target number to <code>f</code>.
 	</Function>
 </Class>
-<Class name='Screen'>
+<Class name='Screen' grouping='Screen'>
 	<Description>
 		<em>Screen</em> is the base screen class containing common methods that all specialized screens inherit.<br />
 		By itself, <em>Screen</em> does not have the layers (underlay, overlay, decorations, in, out, cancel) commonly
@@ -5001,19 +5001,19 @@ Details of the <code>event</code> table:
 		[02 Other.lua] Gets a string from the current Screen in the current language.
 	</Function>
 </Class>
-<Class name='ScreenAttract'>
+<Class name='ScreenAttract' grouping='Screen'>
 </Class>
-<Class name='ScreenEdit'>
+<Class name='ScreenEdit' grouping='Screen'>
 	<Function name='GetEditState' return='EditState' arguments=''>
 		Returns the current <Link class='ENUM' function='EditState' />.
 	</Function>
 </Class>
-<Class name='ScreenEvaluation'>
+<Class name='ScreenEvaluation' grouping='Screen'>
 	<Function name='GetStageStats' return='StageStats' arguments=''>
 		Returns the current StageStats.
 	</Function>
 </Class>
-<Class name='ScreenGameplay'>
+<Class name='ScreenGameplay' grouping='Screen'>
 	<Function name='begin_backing_out' return='' arguments=''>
 		This should behave identically to the normal back button behavior.  This function is for the pause menu to use when the player forfeits or restarts, so that a score isn't saved.
 	</Function>
@@ -5066,7 +5066,7 @@ Details of the <code>event</code> table:
 		Pauses or unpauses the game, depending on the value of <code>bPause</code>.
 	</Function>
 </Class>
-<Class name='ScreenHowToPlay'>
+<Class name='ScreenHowToPlay' grouping='Screen'>
 	<Function name='GetLifeMeter' return='LifeMeter' arguments=''>
 		Returns the LifeMeter.
 	</Function>
@@ -5119,7 +5119,7 @@ Details of the <code>event</code> table:
 		Broadcasts a system message.
 	</Function>
 </Class>
-<Class name='ScreenNameEntryTraditional'>
+<Class name='ScreenNameEntryTraditional' grouping='Screen'>
 	<Function name='Backspace' return='bool' arguments='PlayerNumber pn'>
 		Returns <code>true</code> if Player <code>pn</code> backspaced successfully.
 	</Function>
@@ -5147,18 +5147,18 @@ Details of the <code>event</code> table:
 		Gets the currently selected letter of Player <code>pn</code>.
 	</Function>
 </Class>
-<Class name='ScreenNetEvaluation'>
+<Class name='ScreenNetEvaluation' grouping='Screen'>
 	<Function name='GetNumActivePlayers' return='int' arguments=''>
 		Returns the number of active players.
 	</Function>
 </Class>
-<Class name='ScreenNetRoom'>
+<Class name='ScreenNetRoom' grouping='Screen'>
 </Class>
-<Class name='ScreenNetSelectBase'>
+<Class name='ScreenNetSelectBase' grouping='Screen'>
 </Class>
-<Class name='ScreenNetSelectMusic'>
+<Class name='ScreenNetSelectMusic' grouping='Screen'>
 </Class>
-<Class name='ScreenOptions'>
+<Class name='ScreenOptions' grouping='Screen'>
 	<Function name='AllAreOnLastRow' return='bool'  arguments=''>
 		Returns <code>true</code> if all active players are on the last options row.
 	</Function>
@@ -5175,12 +5175,12 @@ Details of the <code>event</code> table:
 		Returns the specified OptionRow.
 	</Function>
 </Class>
-<Class name='ScreenPlayerOptions'>
+<Class name='ScreenPlayerOptions' grouping='Screen'>
 	<Function name='GetGoToOptions' return='bool' arguments=''>
 		Returns <code>true</code> if we are going to PlayerOptions.
 	</Function>
 </Class>
-<Class name='ScreenProfileLoad'>
+<Class name='ScreenProfileLoad' grouping='Screen'>
 	<Function name='Continue' return='void' arguments=''>
 		Continues to the next screen.
 	</Function>
@@ -5188,7 +5188,7 @@ Details of the <code>event</code> table:
 		Returns <code>true</code> if there is a profile that can be loaded.
 	</Function>
 </Class>
-<Class name='ScreenProfileSave'>
+<Class name='ScreenProfileSave' grouping='Screen'>
 	<Function name='Continue' return='void' arguments=''>
 		Continues to the next screen.
 	</Function>
@@ -5196,12 +5196,12 @@ Details of the <code>event</code> table:
 		Returns <code>true</code> if there is a profile that can be saved.
 	</Function>
 </Class>
-<Class name='ScreenSelectMaster'>
+<Class name='ScreenSelectMaster' grouping='Screen'>
 	<Function name='GetSelectionIndex' return='int' arguments='PlayerNumber pn'>
 		Returns player <code>pn</code>'s current selected item as an integer.
 	</Function>
 </Class>
-<Class name='ScreenSelectMusic'>
+<Class name='ScreenSelectMusic' grouping='Screen'>
 	<Function name='CanOpenOptionsList' return='bool' arguments=''>
 		Returns false if the options list is already open or the UseOptionsList metric is false.
 	</Function>
@@ -5221,7 +5221,7 @@ Details of the <code>event</code> table:
 		[02 StageMods.lua] Sets up modifiers for non-course modes.
 	</Function>
 </Class>
-<Class name='ScreenSelectProfile'>
+<Class name='ScreenSelectProfile' grouping='Screen'>
 	<Function name='Cancel' return='void' arguments=''>
 		Tells the screen to go to the previous screen.
 	</Function>
@@ -5239,7 +5239,7 @@ Details of the <code>event</code> table:
 		• <code>-2</code>: unjoin the player, unlock their MemoryCard, and unmount their MemoryCard
 	</Function>
 </Class>
-<Class name='ScreenTextEntry'>
+<Class name='ScreenTextEntry' grouping='Screen'>
 	<Description>
 		Using ScreenTextEntry is the preferred way to get text input from players.<br />
 		For theming, ScreenTextEntry is unique because it is typically added temporarily to the engine's
@@ -5305,7 +5305,7 @@ local args = {
 </code></pre>
 	</Function>
 </Class>
-<Class name='ScreenWithMenuElements'>
+<Class name='ScreenWithMenuElements' grouping='Screen'>
 	<Function name='Cancel' return='void' arguments=''>
 		Tells the screen to go to the previous screen.
 	</Function>
@@ -5319,7 +5319,7 @@ local args = {
 		Sets whether the screen allows late joining.  This only works for screens that are just ScreenWithMenuElements, as most derived screens have their own hard coded function for whether late joining is allowed.
 	</Function>
 </Class>
-<Class name='ScreenWithMenuElementsSimple'>
+<Class name='ScreenWithMenuElementsSimple' grouping='Screen'>
 </Class>
 <Class name='Song'>
 	<Function name='GetAllSteps' return='{Steps}' arguments=''>
@@ -5708,7 +5708,7 @@ local args = {
 		Returns the warp destination length.
 	</Function>
 </Class>
-<Class name='Sprite'>
+<Class name='Sprite' grouping='Actor'>
 	<Description>
 		<em>Sprite</em> actors can be used to display images and video.  If you want to load a png as part of your UI,
 		or animate a visual effect from a sprite sheet, or play a video file, <em>Sprite</em> is what you're looking for.<br />
@@ -5994,7 +5994,7 @@ local spr = Def.Sprite{
 		Returns <code>true</code> if the Steps use different <code>TimingData</code> from the Song.
 	</Function>
 </Class>
-<Class name='StepsDisplay'>
+<Class name='StepsDisplay' grouping='Actor'>
 	<Function name='Load' return='void' arguments='string sMetricsGroup'>
 		Loads the StepsDisplay commands from the Metrics in group <code>sMetricsGroup</code>.
 	</Function>
@@ -6113,7 +6113,7 @@ local spr = Def.Sprite{
 		Returns true if the note was initiated.
 	</Function>
 </Class>
-<Class name='TextBanner'>
+<Class name='TextBanner' grouping='Actor'>
 	<Function name='Load' return='void' arguments='string sMetricsGroup'>
 		Loads the TextBanner from the specified metrics group.
 	</Function>
@@ -6525,7 +6525,7 @@ local bpms_and_times = timing_data:GetBPMsAndTimes(true)
 		A specific case where this is known to happen is commands that trigger on CurrentSongChanged because the music wheel clears the current song before it finishes loading if the current song is longer than the number of stages remaining.
 	</Function>
 </Class>
-<Class name='WorkoutGraph'>
+<Class name='WorkoutGraph' grouping='Actor'>
 	<Function name='SetFromCurrentWorkout' return='void' arguments=''>
 		Sets the WorkoutGraph from the current Workout.
 	</Function>
@@ -6583,4 +6583,59 @@ SCREENMAN:SystemMessage("hello from Lua!")
 </code></pre>
 </Description>
 </Singletons>
+
+<!--
+	put descriptions for "grouping"s down here
+	these aren't part of the spec in Lua.xsd, so they won't appear
+	when Lua.xml is viewed in a web browser, but can still be used
+	by external API doc applications until ExportLuaInformation
+	is fixed/expanded.
+ -->
+
+<!-- Actors -->
+<Actors>
+	<Description>
+		Actors are the basic building blocks used to script content for StepMania.  When the player
+		sees and interacts with something on-screen, like a menu system or a 3D model of a dancing
+		character, that <em>something</em> is an actor.<br />
+		<br />
+		Each of these actors is available to Lua as a function within the global <code>Def</code> table.<br />
+		<br />
+		As functions, each actor accepts a table as an argument, and that table contains attributes
+		and commands that define how the actor will behave when rendered by the StepMania engine.<br />
+		<br />
+		Basic examples:
+<pre><code>
+-- Sprite, Sound, and Quad are each Actors with unique specializations
+local spr = Def.Sprite{ Texture="./path/to/image.png" }
+local snd = Def.Sound{ File="./path/to/soundeffect.ogg" }
+local sqr = Def.Quad{ InitCommand=function(self) self:xy(80, 100) end }
+
+-- common convention is to not use () with actor
+-- functions, but syntax like this is also valid
+local args = { Texture="./path/to/image.png" }
+local spr  = Def.Sprite(args)
+</code></pre>
+	</Description>
+</Actors>
+
+<Screens>
+	<Description>
+		For players, screens are individual units of a game cycle that they interact with. Most players
+		understand there is a place where gameplay occurs (ScreenGameplay) that is different than the
+		place used to choose the next song (ScreenSelectMusic).<br />
+		<br />
+		For scripters, screens are collections of distinct actors wrapped up in a single
+		ActorFrame.  That ActorFrame is the "screen" that players interact with.<br />
+		<br />
+		To be available in a theme, screens must be defined in that theme's metrics.ini file with the
+		desired name between square brackets like <code>[ScreenTitleJoin]</code> or
+		<code>[ScreenPlayerOptions]</code>.<br />
+		<br />
+		The StepMania engine defines many, many classes of screens, each with unique specialization
+		not directly available to Lua. For now, the screens documented here are only those with methods
+		available to Lua.
+	</Description>
+</Screens>
+
 </Documentation>

From df07b4c649aa5c250b9a05def4ec9ad1b678b542 Mon Sep 17 00:00:00 2001
From: quietly-turning <quietly.turning@gmail.com>
Date: Thu, 25 Jun 2020 05:14:11 -0400
Subject: [PATCH 62/65] update Version, Date in Lua.xml

These elements are normally automatically updated when a new Lua.xml is
generated using the --ExportLuaInformation command line argument, but
I've manually updated them here.  It works for now.

Running --ExportLuaInformation will generate a new Lua.xml file with
everything available to Lua, including some repetitively-named functions
ported from notitg that were manually condensed down within Lua.xml.

We want to keep these condensed parts, so ExportLuaInformation should
probably be fixed/replaced in the future.
---
 Docs/Luadoc/Lua.xml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Docs/Luadoc/Lua.xml b/Docs/Luadoc/Lua.xml
index 3da459c121..3e3415f4ef 100644
--- a/Docs/Luadoc/Lua.xml
+++ b/Docs/Luadoc/Lua.xml
@@ -2981,6 +2981,6 @@
 		<Constant name='right' value='&apos;HorizAlign_Right&apos;'/>
 		<Constant name='top' value='&apos;VertAlign_Top&apos;'/>
 	</Constants>
-	<Version>StepMania5.1-git-d03ec2658f</Version>
-	<Date>2020-05-11</Date>
+	<Version>StepMania5.1-git-89229ed915</Version>
+	<Date>2020-06-25</Date>
 </Lua>

From 39d516f6ded77317a1920cd7ba11804bf1bf4cd4 Mon Sep 17 00:00:00 2001
From: Colby Klein <shakesoda@gmail.com>
Date: Sat, 27 Jun 2020 09:52:52 -0700
Subject: [PATCH 63/65] simplified FTOC for aarch64

this isn't actually a good solution, really RageVColor shouldn't be
doing this conversion at all and should be refactored/removed.

this gets gameplay running a bit smoother, much closer to holding 60fps
---
 src/RageTypes.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/RageTypes.h b/src/RageTypes.h
index c66f635d86..6a2ea018cc 100644
--- a/src/RageTypes.h
+++ b/src/RageTypes.h
@@ -264,6 +264,13 @@ public:
  *
  * should output the same value (+-1) 256 times.  If this function is
  * incorrect, the first and/or last values may be biased. */
+#ifdef CPU_AARCH64
+inline unsigned char FTOC(float a)
+{
+	const float v = a < 0.0f ? 0.0f : (a > 1.0f ? 1.0f : a);
+	return static_cast<unsigned char>(v * 255.0f);
+}
+#else
 inline unsigned char FTOC(float a)
 {
 	//This value is 2^52 * 1.5.
@@ -292,6 +299,7 @@ inline unsigned char FTOC(float a)
 
 	return static_cast<unsigned char>(ret);
 }
+#endif
 
 /* Color type used only in vertex lists.  OpenGL expects colors in
  * r, g, b, a order, independent of endianness, so storing them this

From 4300e37dffce1824100eff11193e4f30f78d2fc3 Mon Sep 17 00:00:00 2001
From: RhythmLunatic <kirbyrulez@att.net>
Date: Sat, 4 Jul 2020 13:24:19 -0500
Subject: [PATCH 64/65] Add example courses and fix typo in Jupiter

---
 Courses/Default/Jupiter.crs                              | 4 ++--
 Docs/Userdocs/Course_Examples/Doubles.crs                | 6 ++++++
 Docs/Userdocs/Course_Examples/Endless Course.crs         | 9 +++++++++
 .../Course_Examples/Forced Modifiers (Advanced).crs      | 8 ++++++++
 .../Course_Examples/Forced Modifiers (Basic).crs         | 5 +++++
 Docs/Userdocs/Course_Examples/Forced Noteskins.crs       | 5 +++++
 Docs/Userdocs/Course_Examples/Pick by meter range.crs    | 7 +++++++
 Docs/Userdocs/Course_Examples/Pick by meter.crs          | 7 +++++++
 Docs/Userdocs/Course_Examples/readme.txt                 | 5 +++++
 9 files changed, 54 insertions(+), 2 deletions(-)
 create mode 100644 Docs/Userdocs/Course_Examples/Doubles.crs
 create mode 100644 Docs/Userdocs/Course_Examples/Endless Course.crs
 create mode 100644 Docs/Userdocs/Course_Examples/Forced Modifiers (Advanced).crs
 create mode 100644 Docs/Userdocs/Course_Examples/Forced Modifiers (Basic).crs
 create mode 100644 Docs/Userdocs/Course_Examples/Forced Noteskins.crs
 create mode 100644 Docs/Userdocs/Course_Examples/Pick by meter range.crs
 create mode 100644 Docs/Userdocs/Course_Examples/Pick by meter.crs
 create mode 100644 Docs/Userdocs/Course_Examples/readme.txt

diff --git a/Courses/Default/Jupiter.crs b/Courses/Default/Jupiter.crs
index c33647c7f9..097e0dad6b 100644
--- a/Courses/Default/Jupiter.crs
+++ b/Courses/Default/Jupiter.crs
@@ -3,7 +3,7 @@
 #METER:Medium:5;
 
 #GAINSECONDS:120;
-#SONG:StepMania 5\Springtime:Medium;nodifficult;
+#SONG:StepMania 5\Springtime:Medium:nodifficult;
 
 #GAINSECONDS:25;
-#SONG:StepMania 5\MechaTribe Assault:Easy;nodifficult;
\ No newline at end of file
+#SONG:StepMania 5\MechaTribe Assault:Easy:nodifficult;
diff --git a/Docs/Userdocs/Course_Examples/Doubles.crs b/Docs/Userdocs/Course_Examples/Doubles.crs
new file mode 100644
index 0000000000..64d78370c3
--- /dev/null
+++ b/Docs/Userdocs/Course_Examples/Doubles.crs
@@ -0,0 +1,6 @@
+#COURSE:Doubles Example;
+#STYLE:DOUBLE;
+#SCRIPTER:Rhythm Lunatic;
+#DESCRIPTION:This course uses the STYLE tag. When AutoSetStyle is enabled the music wheel will pick the Trail generated for doubles charts.;
+#SONG:*:1..20:nodifficult;
+#SONG:*:1..20:nodifficult;
diff --git a/Docs/Userdocs/Course_Examples/Endless Course.crs b/Docs/Userdocs/Course_Examples/Endless Course.crs
new file mode 100644
index 0000000000..76f0f211fc
--- /dev/null
+++ b/Docs/Userdocs/Course_Examples/Endless Course.crs	
@@ -0,0 +1,9 @@
+#COURSE:Endless Course Example;
+#SCRIPTER:Rhythm Lunatic and quietly-turning;
+#DESCRIPTION:This is an example of an endless course using the REPEAT tag.;
+#METER:Challenge:10;
+#SONG:*:Hard;
+#SONG:*:Hard;
+#SONG:*:Hard;
+#SONG:*:Hard;
+#REPEAT:YES;
diff --git a/Docs/Userdocs/Course_Examples/Forced Modifiers (Advanced).crs b/Docs/Userdocs/Course_Examples/Forced Modifiers (Advanced).crs
new file mode 100644
index 0000000000..16103e69ea
--- /dev/null
+++ b/Docs/Userdocs/Course_Examples/Forced Modifiers (Advanced).crs	
@@ -0,0 +1,8 @@
+#COURSE:Forced Modifiers 2;
+#SCRIPTER:Rhythm Lunatic;
+#DESCRIPTION:This course uses the MODS tag for modifiers that can start and stop at different times. It is equivalent to ATTACKS in a simfile.;
+#MODS:TIME=0.00:LEN=60:MODS=Sudden;
+#MODS:TIME=60.00:LEN=60:MODS=Hidden;
+#SONG:StepMania 5\Springtime:Medium:nodifficult;
+#MODS:TIME=0.00:LEN=999:MODS=Dark;
+#SONG:StepMania 5\MechaTribe Assault:Easy:nodifficult;
diff --git a/Docs/Userdocs/Course_Examples/Forced Modifiers (Basic).crs b/Docs/Userdocs/Course_Examples/Forced Modifiers (Basic).crs
new file mode 100644
index 0000000000..bdb191078e
--- /dev/null
+++ b/Docs/Userdocs/Course_Examples/Forced Modifiers (Basic).crs	
@@ -0,0 +1,5 @@
+#COURSE:Forced Modifiers 1;
+#SCRIPTER:Rhythm Lunatic;
+#DESCRIPTION:This course forces modifiers that persist for a song. Forced noteskins do not work currently.;
+#SONG:StepMania 5\Springtime:Medium:nodifficult,flip;
+#SONG:StepMania 5\MechaTribe Assault:Easy:nodifficult,invert;
diff --git a/Docs/Userdocs/Course_Examples/Forced Noteskins.crs b/Docs/Userdocs/Course_Examples/Forced Noteskins.crs
new file mode 100644
index 0000000000..8ecb6be750
--- /dev/null
+++ b/Docs/Userdocs/Course_Examples/Forced Noteskins.crs	
@@ -0,0 +1,5 @@
+#COURSE:Forced Noteskin;
+#SCRIPTER:Rhythm Lunatic;
+#DESCRIPTION:This course has a forced noteskin. You can see it in both pump and dance.;
+#SONG:StepMania 5\Springtime:Medium:nodifficult,delta;
+#SONG:StepMania 5\MechaTribe Assault:Easy:nodifficult,delta,flip;
diff --git a/Docs/Userdocs/Course_Examples/Pick by meter range.crs b/Docs/Userdocs/Course_Examples/Pick by meter range.crs
new file mode 100644
index 0000000000..689b7770f1
--- /dev/null
+++ b/Docs/Userdocs/Course_Examples/Pick by meter range.crs	
@@ -0,0 +1,7 @@
+#COURSE:Pick by meter range;
+#SCRIPTER:Rhythm Lunatic;
+#DESCRIPTION:This course picks a random song and steps in the meter range of 5-10.;
+#SONG:*:5..10:;
+#SONG:*:5..10:;
+#SONG:*:5..10:;
+#SONG:*:5..10:;
diff --git a/Docs/Userdocs/Course_Examples/Pick by meter.crs b/Docs/Userdocs/Course_Examples/Pick by meter.crs
new file mode 100644
index 0000000000..13db71cd88
--- /dev/null
+++ b/Docs/Userdocs/Course_Examples/Pick by meter.crs	
@@ -0,0 +1,7 @@
+#COURSE:Pick by meter;
+#SCRIPTER:Rhythm Lunatic;
+#DESCRIPTION:This course demonstrates picking steps by meter. This limits you to one gamemode and style, unless there are multiple steps with the specified level.;
+
+#SONG:StepMania 5\Springtime:21:nodifficult;
+
+#SONG:StepMania 5\MechaTribe Assault:19:nodifficult;
diff --git a/Docs/Userdocs/Course_Examples/readme.txt b/Docs/Userdocs/Course_Examples/readme.txt
new file mode 100644
index 0000000000..02944ba910
--- /dev/null
+++ b/Docs/Userdocs/Course_Examples/readme.txt
@@ -0,0 +1,5 @@
+These courses demonstrate various features that the engine supports. Drop them in your Courses folder to see.
+Read the #DESCRIPTION tag of the crs files to see what they demonstrate.
+The endless course example will crash the game if you don't have enough songs. If your game is suddenly crashing, remove it.
+
+For more information on courses, check out Docs/CourseFormat.txt or visit https://github.com/stepmania/stepmania/wiki/Courses

From a942ed628bd94fb4254a2720d3be03b1878a001e Mon Sep 17 00:00:00 2001
From: RhythmLunatic <kirbyrulez@att.net>
Date: Sat, 4 Jul 2020 13:27:22 -0500
Subject: [PATCH 65/65] remove forced noteskins course, it doesn't work

---
 Docs/Userdocs/Course_Examples/Forced Noteskins.crs | 5 -----
 1 file changed, 5 deletions(-)
 delete mode 100644 Docs/Userdocs/Course_Examples/Forced Noteskins.crs

diff --git a/Docs/Userdocs/Course_Examples/Forced Noteskins.crs b/Docs/Userdocs/Course_Examples/Forced Noteskins.crs
deleted file mode 100644
index 8ecb6be750..0000000000
--- a/Docs/Userdocs/Course_Examples/Forced Noteskins.crs	
+++ /dev/null
@@ -1,5 +0,0 @@
-#COURSE:Forced Noteskin;
-#SCRIPTER:Rhythm Lunatic;
-#DESCRIPTION:This course has a forced noteskin. You can see it in both pump and dance.;
-#SONG:StepMania 5\Springtime:Medium:nodifficult,delta;
-#SONG:StepMania 5\MechaTribe Assault:Easy:nodifficult,delta,flip;